Isaac I Wirgin

Characterization and expression of cytochrome P4501A in Atlantic sturgeon and shortnose sturgeon experimentally exposed to coplanar PCB 126 and TCDD
Roy NK; Walker N; Chambers RC; Wirgin I
2011 Mar 30;104(1-2):23-31, Aquatic toxicology
The AHR pathway activates transcription of CYP1A and mediates most toxic responses from exposure to halogenated aromatic hydrocarbon contaminants such as PCBs and PCDD/Fs. Therefore, expression of CYP1A is predictive of most higher level toxic responses from these chemicals. To date, no study had developed an assay to quantify CYP1A expression in any sturgeon species. We addressed this deficiency by partially characterizing CYP1A in Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) and shortnose sturgeon (Acipenser brevirostrum) and then used derived sturgeon sequences to develop reverse transcriptase (RT)-PCR assays to quantify CYP1A mRNA expression in TCDD and PCB126 treated early life-stages of both species. Phylogenetic analysis of CYP1A, CYP1B, CYP1C and CYP3A deduced amino acid sequences from other fishes and sturgeons revealed that our putative Atlantic sturgeon and shortnose sturgeon CYP1A sequences most closely clustered with previously derived CYP1A sequences. We then used semi-quantitative and real-time RT-PCR to measure CYP1A mRNA levels in newly hatched Atlantic sturgeon and shortnose sturgeon larvae that were exposed to graded doses of waterborne PCB126 (0.01-1000 parts per billion (ppb)) and TCDD (0.001-10ppb). We initially observed significant induction of CYP1A mRNA compared to vehicle control at the lowest doses of PCB126 and TCDD used, 0.01ppb and 0.001ppb, respectively. Significant induction was observed at all doses of both chemicals although lower expression was seen at the highest doses. We also compared CYP1A expression among tissues of i.p. injected shortnose sturgeon and found significant inducibility in heart, intestine, and liver, but not in blood, gill, or pectoral fin clips. For the first time, our results indicate that young life-stages of sturgeons are sensitive to AHR ligands at environmentally relevant concentrations, however, it is yet to be determined if induction of CYP1A can be used as a biomarker in environmental biomonitoring
— id: 132243, year: 2011, vol: 104, page: 23, stat: Journal Article,

Mechanistic basis of resistance to PCBs in Atlantic tomcod from the Hudson River
Wirgin, Isaac; Roy, Nirmal K; Loftus, Matthew; Chambers, R Christopher; Franks, Diana G; Hahn, Mark E
2011 Mar 11;331(6022):1322-1325, Science
The mechanistic basis of resistance of vertebrate populations to contaminants, including Atlantic tomcod from the Hudson River (HR) to polychlorinated biphenyls (PCBs), is unknown. HR tomcod exhibited variants in the aryl hydrocarbon receptor 2 (AHR2) that were nearly absent elsewhere. In ligand-binding assays, AHR2-1 protein (common in the HR) was impaired as compared to widespread AHR2-2 in binding TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and in driving expression in reporter gene assays in AHR-deficient cells treated with TCDD or PCB126. We identified a six-base deletion in AHR2 as the basis of resistance and suggest that the HR population has undergone rapid evolution, probably due to contaminant exposure. This mechanistic basis of resistance in a vertebrate population provides evidence of evolutionary change due to selective pressure at a single locus
— id: 127231, year: 2011, vol: 331, page: 1322, stat: Journal Article,

DNA methylation in pre-diagnostic serum samples of breast cancer cases: Results of a nested case-control study
Brooks, Jennifer D; Cairns, Paul; Shore, Roy E; Klein, Catherine B; Wirgin, Isaac; Afanasyeva, Yelena; Zeleniuch-Jacquotte, Anne
2010 Dec;34(6):717-723, Cancer Epidemiology
Background: Promoter methylation of tumor suppressor genes is a frequent and early event in breast carcinogenesis. Paired tumor tissue and serum samples from women with breast cancer show that promoter methylation is detectable in both sample types, with good concordance. This suggests the potential for these serum markers to be used for breast cancer detection. Methods: The current study was a case-control study nested within the prospective New York University Women's Health Study cohort aimed to assess the ability of promoter methylation in serum to detect pre-clinical disease. Cases were women with blood samples collected within the 6 months preceding breast cancer diagnosis (n=50). Each case was matched to 2 healthy cancer-free controls and 1 cancer-free control with a history of benign breast disease (BBD). Results: Promoter methylation analysis of four cancer-related genes: -RASSF1A, GSTP1, APC and RARbeta2, - was conducted using quantitative methylation-specific PCR. Results showed that the frequency of methylation was lower than expected among cases and higher than expected among controls. Methylation was detected in the promoter region of: RASSF1A in 22.0%, 22.9% and 17.2% of cases, BBD controls and healthy controls respectively; GSTP1 in 4%, 10.4% and 7.1% respectively; APC in 2.0%, 4.4% and 4.2% respectively and RARbeta2 in 6.7%, 2.3% and 1.1% respectively. Conclusion: Methylation status of the four genes included in this study was unable to distinguish between cases and either control group. This study highlights some methodological issues to be addressed in planning prospective studies to evaluate methylation markers as diagnostic biomarkers
— id: 114817, year: 2010, vol: 34, page: 717, stat: Journal Article,

Fine-scale spatial and temporal genetic structure of Atlantic cod off the Atlantic coast of the USA
Kovach, AI; Breton, TS; Berlinsky, DL; Maceda, L; Wirgin, I
2010 MAY ;410(9):177-U195, Marine ecology progress series
Atlantic cod Gadus morhua in US waters are currently managed as 2 stocks: (1) a Gulf of Maine stock and (2) a Georges Bank and south stock. This designation is decades old and warrants re-evaluation in light of concerns that fisheries management units may not reflect biologically meaningful population units. In this study, we used 10 microsatellite loci, the PanI locus, and 5 single nucleotide polymorphism markers to characterize the population genetic structure of cod in US waters. We found significant differentiation among temporally and spatially divergent populations of cod (global F-ST = 0.0044), primarily stemming from 2 potentially non-neutral loci, and evidence for a population structure that strongly contradicts the current 2-stock management model. This genetic structure was stable over a 5 yr period. Our results indicate that cod in US waters are broadly structured into 3 groups: (1) a northern spring-spawning coastal complex in the Gulf of Maine (GOM), (2) a southern complex consisting of winter-spawning inshore GOM, offshore GOM and sites south of Cape Cod, Massachusetts, and (3) a Georges Bank population. The strongest differentiation occurs between populations in the northern and southern complex (mean F-ST = 0.0085), some of which spawn in the same bays in different seasons. By means of mixture analysis, young-of-the-year fish sampled on juvenile nurseries were assigned to the spawning complex of their origin. Our findings contribute to a growing body of knowledge that Atlantic cod and other marine fish populations are structured on a finer scale than previously thought and that this structure supports biocomplexity and locally adapted populations. As such, it may be warranted to re-evaluate current management units and tailor management plans toward this finer scale
— id: 111899, year: 2010, vol: 410, page: 177, stat: Journal Article,

Delineation of discrete population segments of shortnose sturgeon Acipenser brevirostrum based on mitochondrial DNA control region sequence analysis
Wirgin, I; Grunwald, C; Stabile, J; Waldman, JR
2010 JUN ;11(3):689-708, Conservation genetics
Shortnose sturgeon Acipenser brevirostrum is federally listed as ''an endangered species threatened with extinction'' in the U.S. but its listing status is currently under review. As part of this process, the U.S. National Marine Fisheries Service will determine if shortnose sturgeon are divided into Distinct Population Segments (DPS) across its distribution. In this regard, we sought to determine if shortnose sturgeon occur in genetically 'discrete population segments,' and if so, the boundaries of each. We used mitochondrial DNA (mtDNA) control region sequence analysis to assess the genetic discreteness of 14 of 19 river populations that were recommended as DPS in the 1998 Final Recovery Plan for Shortnose Sturgeon. Nine of the 14 proposed DPS proved significantly discrete (P < 0.05 after Bonferoni correction) from both of their bracketing populations, the exceptions being those in the Penobscot River, Chesapeake Bay, Cooper River, and Ogeechee River (our sample from the Cape Fear River was insufficient to statistically analyze). Haplotype frequencies in the newly 'rediscovered' Penobscot River collection were almost identical to those in the proximal Kennebec River system. Genetic data in combination with tagging results suggest that shortnose sturgeon in the Penobscot River are probably migrants from the Kennebec. Likewise, shortnose sturgeon found today within the Chesapeake Bay appear to be migrants from the Delaware River. While haplotype frequencies in the remnant Santee River population in Lake Marion differed significantly from those in nearby Winyah Bay, they did not differ significantly from those in the Cooper River. This suggests that the Cooper River harbors descendants of the Santee River population that are unable to access their historical spawning locales. The Ogeechee River collection was not genetically distinct from that in the nearby Savannah River, suggesting that it may host descendants of hatchery-reared individuals of Savannah River ancestry. Our genetic results indicate that most, but not all, rivers with shortnose sturgeon host genetically discrete populations, constituting important information in the consideration of DPS designations. However, shortnose sturgeon migrations through coastal waters to proximal rivers and release of hatchery-reared fish may confound results from genetic studies such as ours and lead to the possible misidentification of discrete population segments
— id: 109967, year: 2010, vol: 11, page: 689, stat: Journal Article,

Microarray analysis of polychlorinated biphenyl mixture-induced changes in gene expression among Atlantic tomcod populations displaying differential sensitivity to halogenated aromatic hydrocarbons
Carlson, Erik A; Roy, Nirmal K; Wirgin, Isaac I
2009 Apr;28(4):759-771, Environmental toxicology & chemistry
Several populations of fishes inhabiting contaminated Atlantic Coast estuaries exhibit resistance to early life-stage (ELS) toxicities induced by halogenated aromatic hydrocarbons such as coplanar polychlorinated biphenyls (PCBs). These toxicities include mortality, circulatory failure, edema, and craniofacial malformations. The mechanisms behind resistance to halogenated aromatic hydrocarbon toxicity in these populations are unknown. First and second generation Atlantic tomcod Microgadus tomcod embryos derived from the Hudson River ([HR]; New York, USA) population are highly resistant to PCB-induced cytochrome P4501A (CYP1A) expression and ELS toxicity when compared to embryos of Miramichi River ([MR]; New Brunswick, Canada) and Shinnecock Bay ([SB]; New York, USA) origin. The present study sought to identify novel genes involved in population differences in response to PCB exposure using custom microarrays. Microarray probes consisted of unsequenced inserts of randomly picked clones from a tomcod cardiac cDNA library. Tomcod embryos from three populations (HR, MR, and SB) were exposed to two doses of an environmentally relevant mixture of coplanar PCBs and screened for dose- and population-specific patterns of gene expression. Clones displaying significant differences between populations exposed to the high dose of PCBs were identified by DNA sequencing. Of the 28 identified nonribosomal protein clones, none displayed expression patterns highly similar to CYP1A (altered in MR and SB, but not in HR). However, several transcripts representing biomarkers of cardiomyopathy in mammals (cardiac troponin T2, cathepsin L, and atrial natriuretic peptide) were differentially altered among the three tomcod populations by PCBs. Although the present study did not identify any novel genes associated with PCB resistance in tomcod, several potential molecular biomarkers of PCB exposure were revealed
— id: 120712, year: 2009, vol: 28, page: 759, stat: Journal Article,

Development and Use of Real-Time Reverse Transcription-Polymerase Chain Reaction Assay to Quantify Cytochrome P4501A1 Expression in American Mink
Roy, Nirmal K; Bursian, Steve; Mayack, David T; Wirgin, Isaac
2009 Oct;57(3):608-615, Archives of environmental contamination & toxicology
The distribution of natural populations of American mink is restricted to locales that are in proximity to aquatic ecosystems. Because of the lipophilicity and persistence of polychlorinated biphenyls (PCBs) and reliance of mink on aquatic-based diets, mink at contaminated locales often bioacccumulate high levels of PCBs. In addition, in controlled laboratory studies, mink are highly sensitive at reproductive and developmental end points to the toxic effects of environmental PCB mixtures. It is believed that most, if not all, toxic effects of PCBs occur through activation of the aryl hydrocarbon receptor (AHR) pathway. Transcription of cytochrome P4501A1 (CYP1A1) by PCBs is also mediated through activation of AHR. Thus, levels of CYP1A1 mRNA provide a quantitative assay of exposure to and early biologic effect of PCBs on mink and may be predictive of toxicity at higher levels of biologic organization. We developed polymerase chain reaction (PCR) primers to amplify CYP1A1 as well as identified a housekeeping gene from mink cDNA. We used real-time reverse transcription-PCR to quantify and compare levels of hepatic CYP1A mRNA among groups of ranched mink kits and juveniles, which were fed diets or exposed in utero to fish that were low in PCBs (Atlantic herring) or to diets that were contaminated with three different levels of PCBs (carp) from Saginaw Bay, Lake Michigan. We found significant differences in CYP1A1 mRNA expression between mink fed the control diet and those fed a PCB-contaminated carp diet at all three treatment levels and exposure times. CYP1A1 mRNA was significantly induced 5.3- to 6.6-fold and 3.7- to 4.7-fold at 6 and 27 weeks, respectively. In previous studies, dietary exposures to PCB-contaminated carp were shown to cause mild to moderate lesions in the mandible and maxilla of these animals. This study demonstrates that hepatic CYP1A1 mRNA may be a sensitive biomarker of exposure of mink to environmentally relevant levels of PCBs and may be predictive of their effects in natural populations
— id: 94578, year: 2009, vol: 57, page: 608, stat: Journal Article,

Mitochondrial DNA Analysis Indicates Sea Lampreys Are Indigenous to Lake Ontario: Response to Comment
Waldman, J; Daniels, R; Hickerson, M; Wirgin, I
2009 SEP ;138(5):1190-1197, Transactions of the American Fisheries Society
— id: 105455, year: 2009, vol: 138, page: 1190, stat: Journal Article,

Polymorphisms in RAD51, XRCC2, and XRCC3 are not related to breast cancer risk
Brooks, Jennifer; Shore, Roy E; Zeleniuch-Jacquotte, Anne; Currie, Diane; Afanasyeva, Yelena; Koenig, Karen L; Arslan, Alan A; Toniolo, Paolo; Wirgin, Isaac
2008 Apr;17(4):1016-1019, Cancer epidemiology biomarkers & prevention
— id: 80287, year: 2008, vol: 17, page: 1016, stat: Journal Article,

Vitamin D receptor polymorphisms and risk of epithelial ovarian cancer
Clendenen, Tess V; Arslan, Alan A; Koenig, Karen L; Enquist, Kerstin; Wirgin, Isaac; Agren, Asa; Lukanova, Annekatrin; Sjodin, Hubert; Zeleniuch-Jacquotte, Anne; Shore, Roy E; Hallmans, Goran; Toniolo, Paolo; Lundin, Eva
2008 Feb 18;260(1-2):209-215, Cancer letters
The vitamin D receptor (VDR) is a critical mediator of the cellular effects of vitamin D. The associations between four common VDR polymorphisms (BSMI, APAI, TAQI, and FOKI) and risk of epithelial ovarian cancer (EOC) were assessed in a case-control study nested within two prospective cohorts. One hundred seventy incident cases of EOC and 323 individually matched controls were genotyped. Overall, no associations were observed in genotype analyses. Haplotypes combining three SNPs in high linkage disequilibrium (BSMI, APAI, and TAQI) were also not associated with risk. These observations do not support a role for BSMI, APAI, TAQI, and FOKI polymorphisms in epithelial ovarian cancer in a predominantly Caucasian population
— id: 76858, year: 2008, vol: 260, page: 209, stat: Journal Article,

Conservation of Atlantic sturgeon Acipenser oxyrinchus oxyrinchus: delineation of stock structure and distinct population segments
Grunwald, C; Maceda, L; Waldman, J; Stabile, J; Wirgin, I
2008 JUL-AUG ;9(5):1111-1124, Conservation genetics
The anadromous Atlantic sturgeon Acipenser oxyrinchus oxyrinchus, a wide-ranging species along the Atlantic Coast of North America, is being considered for federal listing under the U.S. Endangered Species Act. Identification of distinct population segments (DPS) is necessary but problematic for highly vagile species such as Atlantic sturgeon which may spend a high proportion of their lives outside of their natal estuaries. Characterization of genetic differentiation and estimates of gene flow provide a quantitative measure of the number of DPS into which species could be divided over their distribution and the reproductive independence of each unit. We sequenced a portion of the mitochondrial DNA control region to characterize population structure and gene flow across all naturally reproducing populations from which specimens could be obtained. We then considered these genetic data along with ancillary information on life history characteristics, historical fisheries data, and trajectories of abundance to determine the number of DPS into which this species should be divided. Our results suggest that philopatry is high for Atlantic sturgeon and that each U.S. estuary analyzed hosts genetically distinct populations of Atlantic sturgeon. We conclude that at least nine DPS of Atlantic sturgeon exist along the Atlantic Coast of the U.S. In contrast, the Atlantic Sturgeon Status Review Team has proposed a five DPS scheme for this subspecies based largely on results from nuclear DNA microsatellites, but with fewer populations represented and lower samples sizes. These different conclusions illustrate the somewhat arbitrary nature of the DPS concept, at least as applied to Atlantic sturgeon
— id: 86667, year: 2008, vol: 9, page: 1111, stat: Journal Article,

Annual run size and genetic characteristics of Atlantic sturgeon in the Altamaha River, Georgia
Peterson, DL; Schueller, P; DeVries, R; Fleming, J; Grunwald, C; Wirgin, I
2008 MAR ;137(2):393-401, Transactions of the American Fisheries Society
Although the Altamaha River, Georgia, once supported one of the largest fisheries for Atlantic sturgeon Acipenser oxyrinchus in U.S. waters, the fishery was closed in 1997 because of severe overfishing. Since then, no studies have been conducted and population trends have remained unknown. The objective of this study was to estimate annual run size and age structure of the spring spawning migration and to determine genetic relatedness between this population and other Georgia populations. In spring of 2004 and 2005, we sampled the annual spawning run of Atlantic sturgeon in the lower 30 km of the Altamaha River using large-mesh gill nets. Captured fish were marked with passive integrated transponder tags and released to facilitate a run estimate using a simple Schnabel mark-recapture estimator. Over the 2 years of the study, we captured 213 individuals, yielding mark-recapture run estimates of 324 (95% confidence interval [CI] = 143-667) in 2004 and 386 (95% CI = 216-787) in 2005. Catch curve analysis yielded annual mortality rates of 17.3% in 2004 and 21.3% in 2005. Genetic analysis showed that the Altamaha River population is distinct from neighboring populations in the Ogeechee and Savannah rivers. The results of this study suggest that after 10 years of federal protection, the Altamaha River population of Atlantic sturgeon appears to be in the early stages of recovery; however, the genetic diversity of the population is surprisingly low. Future Studies are needed to monitor population dynamics and genetic structure of the stock to ensure complete recovery
— id: 78717, year: 2008, vol: 137, page: 393, stat: Journal Article,

Polymorphisms in XPC and ERCC2 genes, smoking and breast cancer risk
Shore, Roy E; Zeleniuch-Jacquotte, Anne; Currie, Diane; Mohrenweiser, Harvey; Afanasyeva, Yelena; Koenig, Karen L; Arslan, Alan A; Toniolo, Paolo; Wirgin, Isaac
2008 May 1;122(9):2101-2105, International journal of cancer
To evaluate the associations of breast cancer risk with polymorphisms in the XPC and XPD/ERCC2 DNA nucleotide excision repair genes, a case-control study nested within a prospective cohort of 14,274 women was conducted. Genotypes were characterized for 612 incident, invasive breast cancer cases and their 1:1 matched controls. The homozygous variant of a poly(AT) insertion/deletion polymorphism in intron 9 of the XPC gene (XPC-PAT+/+), was associated with breast cancer risk [odds ratio (OR) = 1.45, 95% confidence interval: 1.07-1.97], after adjustment for other breast cancer risk factors. The breast cancer risk associated with XPC-PAT+/+ did not differ by age at diagnosis. There was an indication of an interaction (p = 0.08) between the XPC-PAT+/+ genotype and cigarette smoking. Ever smokers with the XPC-PAT+/+ genotype were at elevated risk of breast cancer (OR = 1.56, CI: 0.95-2.58), but no differences were observed among never smokers. Analyses of the ERCC2 Lys751Gln polymorphism did not show an association with breast cancer risk, either overall or at younger ages. The results suggest that breast cancer risk is related to the XPC haplotype tagged by the XPC-PAT+/+ insertion-deletion polymorphism in intron 9. Further study of the XPC haplotypes and their interactions with smoking in relation to breast cancer risk is needed
— id: 76390, year: 2008, vol: 122, page: 2101, stat: Journal Article,

Sea lamprey Petromyzon marinus: an exception to the rule of homing in anadromous fishes
Waldman, John; Grunwald, Cheryl; Wirgin, Isaac
2008 Dec 23;4(6):659-662, Biology Letters
Anadromous fishes are believed to make regular circuits of migration in the sea before homing to their natal rivers. Sea lamprey Petromyzon marinus is an anadromous fish that is an exception to this life-history pattern. It also differs from other anadromous fishes in that its adult phase is parasitic, a feeding strategy that should make homing problematic for lamprey cohorts that become widely dispersed through transport by the diverse hosts they parasitize. We sequenced a portion of the mitochondrial DNA control region from sea lampreys collected from 11 North American east coast rivers to test for genetic evidence of homing. There were no significant differences (chi2=235.1, p=0.401) in haplotype frequencies among them, with almost 99 per cent of haplotypic diversity occurring within populations. These findings, together with concordant genetic results from other geographical regions and ancillary information on pheromonal communication, suggest that sea lamprey does not home but rather exhibits regional panmixia while using a novel 'suitable river' strategy to complete its life cycle
— id: 120710, year: 2008, vol: 4, page: 659, stat: Journal Article,

Molecular analysis as a conservation tool for monitoring the trade of North American sturgeons and paddlefish
Waldman, JR; Doukakis, P; Wirgin, I
2008 JUN ;24(1):20-28, Journal of applied ichthyology
There are nine acipenseriform species in North America: two on the Pacific Coast, two on the Atlantic Coast, and five purely freshwater forms. Six of these species are subject to commercial harvest and three to aquaculture. The North American sturgeon and paddlefish meat and caviar marketplace is comprised of legally and illegally acquired products from wild and captive populations of indigenous species as well as non-indigenous species from import and/or culture. Overall, at least 11 species can legally occur in the market. Future aquaculture development will most certainly increase this number. Some indigenous species subject to commercial harvest or culture are under partial or complete range protection, adding another layer of monitoring complexity at the population specific level. We identify four primary levels of confusion in the identification of caviar from North American acipenseriforms in North America: among North American species, among populations within a North American species, between wild and farmed specimens of a North American species, and between North American and imported non-North American species. This complexity reveals the need for additional research into forensic tools, species boundaries and population structure if effective enforcement of harvest and market restrictions is to ensue. For species not subject to commercial harvest and trade, research is needed to identify illegal products from the species
— id: 78392, year: 2008, vol: 24, page: 20, stat: Journal Article,

Genetic evidence for relict Atlantic sturgeon stocks along the mid-Atlantic coast of the USA
Wirgin, I; Grunwald, C; Stabile, J; Waldman, J
2007 NOV ;27(4):1214-1229, North American journal of fisheries management
The Atlantic sturgeon Acipenser oxyrinchus oxyrinchus is a highly migratory anadromous acipenserid that is distributed along the Atlantic coast of North America. The abundance of Atlantic sturgeon has not increased appreciably in recent years despite the imposition of a moratorium on its harvest in U.S. waters in 1998. Two measures being considered to restore depleted or extirpated populations are designation of Atlantic sturgeon as federally endangered under the U.S. Endangered Species Act and the use of hatchery-reared fish to supplement natural reproduction. Implementation of these approaches requires detailed knowledge of this species' population structure. Previous genetic stock identification studies failed to address the discreteness of Atlantic sturgeon populations along the U.S. mid-Atlantic coast that historically supported two of the largest fisheries for the species. We used mitochondrial DNA (mtDNA) control region sequence data to elucidate the population structure of Atlantic sturgeon in the Delaware River and two tributaries of Chesapeake Bay, the James and York rivers. Haplotypes of individuals from these rivers were compared with those from 14 other estuaries. Levels of mtDNA diversity were moderately high; 45 haplotypes were observed among the 860 specimens analyzed. We found significant temporal instability of haplotypes among collections of subadults made in different years from the Delaware River, including haplotypes not seen elsewhere and others that were common in the adjoining Hudson River and Albemarle Sound. Ibis finding suggests that natural reproduction of a genetically distinct population still occurs in the Delaware River, but that it also hosts migrant subadults from elsewhere. In contrast, temporal instability of haplotype frequencies was absent among collections from different years in the Hudson River. Although private haplotypes were absent from the James and York River samples, significant frequency differences between these collections and those from elsewhere suggest that some tributaries of Chesapeake Bay still host genetically unique populations of Atlantic sturgeon
— id: 75692, year: 2007, vol: 27, page: 1214, stat: Journal Article,

Bioaccumulation and toxicities of aromatic hydrocarbon contaminants at different trophic levels of the Hudson River ecosystem
Wirgin, Isaac I.
Environmental and occupational medicine Philadelphia : Wolters Kluwer/Lippincott Williams & Wilkins, 2007,
— id: 5378, year: 2007, vol: , page: ?, stat: Chapter,

Characterization of the aryl hydrocarbon receptor repressor and a comparison of its expression in Atlantic tomcod from resistant and sensitive populations
Roy, Nirmal K; Courtenay, Simon C; Chambers, R Christopher; Wirgin, Isaac I
2006 Feb;25(2):560-571, Environmental toxicology & chemistry
Atlantic tomcod from the Hudson River, USA, are resistant to cytochrome P4501A1 (CYP1A1) mRNA induction and early life stage toxicities induced by coplanar polychlorinated biphenyls (PCBs) or tetrachlorodibenzo-p-dioxins but not polycyclic aromatic hydrocarbons. We sought to determine if basal expression or inducibility of aryl hydrocarbon receptor repressor (AHRR) mRNA is higher in tomcod from the resistant Hudson River population than in those from sensitive populations. Tomcod AHRR cDNA was characterized and its expression quantified in different tissues and life stages of tomcod from the Hudson River, Miramichi River, Canada (sensitive), and among environmentally exposed tomcod from these two sources and the St. Lawrence River, Canada. Phylogenetic analysis revealed that tomcod AHRR falls within the clade of other vertebrate aryl hydrocarbon receptors (AHRs) but is most closely related to the four previously identified AHRR genes. Induction of AHRR mRNA was observed in all tissues of PCB77-treated juvenile tomcod of Miramichi River descent, and expression differed among tissues and was significantly related to levels of CYPIAI mRNA expression. Aryl hydrocarbon receptor repressor mRNA was similarly inducible in F2 embryos of Miramichi and Hudson River descent by benzo[a]pyrene but less by PCB77 in Hudson River offspring. A significant, positive correlation was observed between CYP1A1 mRNA and AHRR mRNA concentrations in environmentally exposed tomcod from the three rivers. We conclude that differences in basal expression or inducibility of AHRR mRNA are not the mechanistic basis of resistance but that levels of AHRR often mirror those of CYP1A1, suggesting that a common AHR pathway-related mechanism may modulate expression of both genes
— id: 64648, year: 2006, vol: 25, page: 560, stat: Journal Article,

Evaluation of the native status of sea lampreys in Lake Champlain based on mitochondrial DNA sequencing analysis
Waldman, JR; Grunwald, C; Wirgin, I
2006 JUL ;135(4):1076-1085, Transactions of the American Fisheries Society
Adult sea lampreys Petromyzon marinus parasitize a variety of recreationally, commercially, and ecologically important fishes in the north temperate Atlantic Ocean and some inland waters of North America, including the Great Lakes and Lake Champlain. This has resulted in the development of international, provincial, and state programs to suppress their abundance in some of these waters. This effort, in part, emanates from the normative status afforded sea lampreys in these lakes by management agencies. However, whether the sea lamprey is native to Lake Champlain has long been debated, and the outcome of this debate may impact the intensity of efforts to suppress their abundance there. We addressed this issue by using sequence analysis of the mitochondrial DNA control region. Resultant haplotype frequencies of sea lampreys from the Lake Champlain watershed were compared among sea lamprey collections made in multiple drainages within the Lake Ontario and Lake Superior watersheds and Atlantic coast rivers. We found no evidence of population structuring among tributaries within any of these four systems, but we did find highly significant genetic differentiation between systems. Haplotype diversity was low in the collections from the two Great Lakes and even more so in those from Lake Champlain compared with that in Atlantic coast rivers. Our genetic results are most consistent with the hypothesis that sea lampreys are native to Lake Champlain, having colonized the lake postglacially by one of several zoogeographic corridors
— id: 68667, year: 2006, vol: 135, page: 1076, stat: Journal Article,

Evidence of spatially extensive resistance to PCBs in an anadromous fish of the Hudson River
Yuan, Zhanpeng; Courtenay, Simon; Chambers, R Christopher; Wirgin, Isaac
2006 Jan;114(1):77-84, Environmental health perspectives
Populations of organisms that are chronically exposed to high levels of chemical contaminants may not suffer the same sublethal or lethal effects as naive populations, a phenomenon called resistance. Atlantic tomcod (Microgadus tomcod) from the Hudson River, New York, are exposed to high concentrations of polycyclic aromatic hydrocarbons (PAHs) and bioaccumulate polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). They have developed resistance to PCBs and PCDDs but not to PAHs. Resistance is largely heritable and manifests at early-life-stage toxic end points and in inducibility of cytochrome P4501A (CYP1A) mRNA expression. Because CYP1A induction is activated by the aryl hydrocarbon receptor (AHR) pathway, as are most toxic responses to these compounds, we sought to determine the geographic extent of resistance to CYP1A mRNA induction by PCBs in the Hudson River tomcod population. Samples of young-of-the-year tomcod were collected from seven locales in the Hudson River, extending from the Battery at river mile 1 (RM 1) to RM 90, and from the Miramichi River, New Brunswick, Canada. Laboratory-reared offspring of tomcod adults from Newark Bay, in the western portion of the Hudson River estuary, were also used in this study. Fish were partially depurated in clean water and intraperitoneally injected with 10 ppm coplanar PCB-77, 10 ppm benzo[a]pyrene (BaP), or corn oil vehicle, and levels of CYP1A mRNA were determined. CYP1A was significantly inducible by treatment with BaP in tomcod from the Miramichi River, from laboratory-spawned offspring of Newark Bay origin, and from all Hudson River sites spanning 90 miles of river. In contrast, only tomcod from the Miramichi River displayed significantly induced CYP1A mRNA expression when treated with PCB-77. Our results suggest that the population of tomcod from throughout the Hudson River estuary has developed resistance to CYP1A inducibility and probably other toxicities mediated by the AHR pathway. Tomcod from the Hudson River may represent the most geographically expansive population of vertebrates with resistance to chemical pollutants that has been characterized
— id: 62747, year: 2006, vol: 114, page: 77, stat: Journal Article,

Comparison of hepatic and extra hepatic induction of cytochrome P4501A by graded doses of aryl hydrocarbon receptor agonists in Atlantic tomcod from two populations
Yuan, Zhanpeng; Courtenay, Simon; Wirgin, Isaac
2006 Mar 10;76(3-4):306-320, Aquatic toxicology
Atlantic tomcod Microgadus tomcod from the Hudson River, New York, are exposed to high levels of polycyclic aromatic hydrocarbons (PAHs) and bioaccumulate mixtures of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and polychlorinatedfurans (PCDD/Fs). Previous studies demonstrated that hepatic cytochrome P4501A (CYP1A) mRNA was not inducible in tomcod from the Hudson River treated with single doses of PCB77 or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), but was inducible with PAHs. In this study, we sought to determine if CYP1A mRNA was inducible with higher doses of these and other halogenated aromatic hydrocarbons (HAHs) in Hudson River tomcod and if decreased sensitivity to gene inducibility occurs across all tissues. Tomcod from the Hudson River and the cleaner Miramichi River, New Brunswick, were treated individually with graded doses of TCDD and coplanar PCBs (PCB77, PCB81, PCB126, PCB169) and profiles of hepatic CYP1A mRNA expression were compared between the two populations. CYP1A mRNA inducibility was also compared in multiple tissues of tomcod from the two rivers that were treated with PCB77. Additionally, hepatic CYP1A mRNA was characterized in Miramichi River tomcod treated with pairs of PCB congeners that included aryl hydrocarbon receptor (AHR) agonists and antagonists. Hepatic CYP1A mRNA was significantly inducible by all agonists in tomcod from the Miramichi River and TCDD and two of four PCBs in tomcod from the Hudson River. CYP1A mRNA was also significantly inducible in four of five tissues of tomcod from the Miramichi River but only in liver of Hudson River tomcod. In summary, CYP1A mRNA inducibility was approximately two orders of magnitude less sensitive in tomcod from the Hudson River than in those from the Miramichi River. But when achieved, maximum levels of CYP1A expression were similar in tomcod from the two populations. Co-administration of PCB126 and PCB77 did not produce significantly greater CYP1A mRNA induction than administration of PCB126 alone and co-administration of mono-ortho-substituted PCB105 significantly decreased CYP1A mRNA inducibility by PCB77. These results indicate that CYP1A mRNA expression is significantly inducible by HAHs in tomcod from the Hudson River and suggest that all components of the AHR pathway are present and functional, but that the pathway is less sensitive to activation than in tomcod from the Miramichi River. Our results also indicate that CYP1A mRNA levels in environmentally exposed fish may not reflect additive tissue burdens of PCB congeners
— id: 71578, year: 2006, vol: 76, page: 306, stat: Journal Article,

Biomarkers of benzene: Urinary metabolites in relation to individual genotype and personal exposure
Qu, Qingshan; Shore, Roy; Li, Guilan; Su, Lin; Jin, Ximei; Melikian, Asseih A; Roy, Nirmal; Chen, Lung Chi; Wirgin, Isaac; Cohen, Beverly; Yin, Songnian; Li, Yuying; Mu, Ruidong
2005 May 30;153-154:85-95, Chemico-biological interactions
This report is part of an extensive biomarker study conducted in a Chinese occupational population with benzene exposures ranging from 0.06 to 122ppm (median exposure of 3.2ppm). All urinary benzene metabolites measured in this study were significantly elevated after exposure to benzene at or above 5ppm. Among these metabolites, however, only S-phenylmercapturic acid (S-PMA) and trans,trans-muconic acid (t,t-MA) showed a significant exposure-response trend over the exposure range from 0 to 1ppm (for S-PMA, p<0.0001 and for t,t-MA, p=0.006). For benzene exposure monitoring, both S-PMA and t,t-MA were judged to be good and sensitive markers, which detected benzene exposure at around 0.1 and 1ppm, respectively. Polymorphisms of the metabolic genes, including CYP2E1, quinone oxidoreductase (NQO1), GSTT1, and myeloperoxidase (MPO), were identified and did not show significant effects on the formation of metabolites, except GSTT1 on S-PMA. The production rate of S-PMA from benzene in exposed workers with GSTT1 null alleles (24.72+/-32.48mug/g creatinine/ppm benzene) was significantly lower than that in subjects with the wild type of GSTT1 (59.84+/-47.66mug/g creatinine/ppm benzene, p<0.0001). Further regression analysis of S-PMA production rate on GSTT1 genotype with adjustment of sex, age, benzene exposure, and cotinine levels indicated that the genotype of GSTT1 plays a critical role in determining the inter-individual variations of S-PMA formation from benzene exposure. Therefore, the individual genotype of GSTT1 needs to be identified and considered while using S-PMA as a marker to estimate the personal exposure levels of benzene in future population studies
— id: 56002, year: 2005, vol: 153-154, page: 85, stat: Journal Article,

Co-exposure to metals modulates CYP1A mRNA inducibility in Atlantic tomcod Microgadus tomcod from two populations
Sorrentino, C; Roy, N K; Courtenay, S C; Wirgin, I
2005 Nov 10;75(3):238-252, Aquatic toxicology
Populations from urbanized and industrialized sites are often exposed to mixtures of chemical contaminants including aromatic hydrocarbons (AHs) and heavy metals. The effects of mixtures of these contaminants on these populations are largely unknown. The Hudson River Estuary is highly contaminated with a variety of AHs including, PCBs and PAHs, and metals, and its population of Atlantic tomcod Microgadus tomcod bioaccumulates those which are persistent. The Hudson River's tomcod population exhibits resistance to persistent AHs as exemplified by significantly decreased inducibility of hepatic cytochrome P4501A (CYP1A) mRNA. We used hepatic CYP1A mRNA inducibility in tomcod from the Hudson River and a sensitive population to investigate the effects of acute co-exposure to metals on aryl hydrocarbon receptor (AHR)-mediated gene expression. Adult tomcod from the Hudson River and the cleaner Miramichi River were i.p. injected with one dose of benzo[a]pyrene (B[a]P) or coplanar PCB77 and graded doses of four metals, As, Cd, Cr, and Ni, and levels of hepatic CYP1A mRNA and protein were assayed. We observed no effects of metals treatment on basal levels of hepatic CYP1A mRNA expression, but all four metals significantly reduced CYP1A mRNA inducibility in tomcod from one or both populations. The magnitude of the inhibition of CYP1A mRNA inducibility differed among the metals and fish from the two populations. Also, the profile of the metals modulation of induced CYP1A mRNA showed differences that depended on the time after treatment of sacrifice. Our results demonstrate that co-exposure to several metals can impact inducible, but not basal levels of CYP1A expression and perhaps other toxicities mediated by the AHR
— id: 64452, year: 2005, vol: 75, page: 238, stat: Journal Article,

Introgression of nuclear DNA (nDNA) alleles of stocked Atlantic coast striped bass with the last remaining native gulf of Mexico population
Wirgin, I; Currie, D; Roy, N; Maceda, L; Waldman, JR
2005 MAY ;25(2):464-474, North American journal of fisheries management
Since the 1960s, only the Apalachicola-Chattahoochee-Flint (ACF) river system has continually supported a naturally reproducing population of striped bass Morone saxatilis of Gulf of Mexico (Gulf) lineage. Striped bass fry and fingerlings of Atlantic ancestry (from the Santee-Cooper system) were introduced into the ACF from the late 1960s to 1977. Genotypes were previously identified that were unique to fish from the ACF and that confirmed the continued natural reproduction of striped bass of Gulf ancestry within that population. Also, no significant difference in haplotype frequencies between 'pure' archived ACF and extant ACF samples was found at an Xba I mitochondrial DNA (mtDNA) restriction site that is diagnostic in distinguishing extant ACF from extant Atlantic specimens. This suggested that significant maternally mediated introgression of Atlantic mtDNA genomes has not occurred. However, because mtDNA is maternally inherited, the introgression of paternally derived nuclear DNA alleles into the ACF gene pool was not evaluated. In this study, five microsatellite loci were identified that were diagnostic in distinguishing between extant Atlantic and ACF fish. The frequencies of diagnostic alleles at three of these loci were determined in archived scale samples of Gulf striped bass from the ACF and Atlantic fish from the St. Johns River along the Atlantic coast of Florida. Fixed differences in allelic identity were found between the archived collections at two loci and significant frequency differences at the third. Significant allelic frequency differences at all three loci were found between extant ACF samples collected over 8 years and the archived ACF collection. These were used to estimate that the degree of introgression of alleles of Santee-Cooper origin with the extant ACF population is 0.515. Despite the introgression of Atlantic alleles, management efforts to restore the ACF population are warranted because of continued successful natural reproduction and the substantial frequencies of unique Gulf alleles in its population
— id: 56196, year: 2005, vol: 25, page: 464, stat: Journal Article,

Range-wide population structure of shortnose sturgeon Acipenser brevirostrum based on sequence analysis of the mitochondrial DNA control region
Wirgin, I; Grunwald, C; Carlson, E; Stabile, J; Peterson, DL; Waldman, J
2005 JUN ;28(3):406-421, Estuaries
Riverine populations of shortnose sturgeon (Acipenser brevirostrum) once occurred in rivers and estuaries along the east coast of North America from the St. John River, New Brunswick, to the St. Johns River, Florida. Within this range, 19 population segments were identified by the U.S. Federal Shortnose Sturgeon Recovery Team; empirical data supporting this structure is limited. We obtained samples from 11 (12 including a small sample from the Cape Fear River, North Carolina) of these population segments and used PCR and direct sequence analysis of 440 base pairs of the mitochondrial DNA (mtDNA) control region to define the coast-wide genetic population structure of shortnose sturgeon. Collections from most population segments exhibited significant differences in haplotype frequencies with their nearest neighbors, including from the Ogeechee and Savannah Rivers, Georgia (despite the known movement of hatchery reared offspring from the Savannah into the Ogeechee River). Collections from the Chesapeake Bay and Delaware River exhibited similar haplotype frequencies, suggesting that specimens collected in the Chesapeake Bay had dispersed from the Delaware River. Collections from the Kennebec River and Androscoggin River within a hypothesized single population segment did not exhibit significant differentiation of mtDNA haplotype frequencies. Haplotype frequencies were almost identical between collections from above and below the Holyoke Dam on the Connecticut River, indicating that these aggregations should be managed as a single unit. Our results support the population segment status afforded to shortnose sturgeon in at least the following 9 systems; St. John River, Kennebec-Androscoggin Rivers, upper-lower Connecticut River, Hudson River, Delaware River-Chesapeake Bay, Pee Dee River, Cooper River, Savannah River, and Ogeechee-Altamaha Rivers
— id: 57650, year: 2005, vol: 28, page: 406, stat: Journal Article,

Reduction of cytochrome P4501A with age in Atlantic tomcod from the St. Lawrence Estuary, Canada: relationship with emaciation and possible effect of contamination
Couillard, C M; Wirgin, I I; Lebeuf, M; Legare, B
2004 Jun 24;68(3):233-247, Aquatic toxicology
This study reports a reduction of ethoxyresorufin-O-deethylase (EROD) activity in large-sized, older Atlantic tomcod (Microgadus tomcod) collected in the St. Lawrence Estuary (Quebec, Canada) and investigates its relationship over a 4-year period to sex, gonadosomatic index (GSI), condition factor (CF) and cytochrome P4501A (CYP1A) mRNA levels. In addition, the concentrations of polychlorinated biphenyls (PCBs) were measured in a subsample of fish. The reduction of EROD activity with age was observed each year in both sexes and was not related to the GSI. A high proportion of large-sized fish, with a body length greater or equal to 225 mm, were emaciated (CF < or = 0.55). A 6-16-fold reduction of EROD activity and a 2-4-fold reduction of CYP1A mRNA levels were observed in large-sized emaciated females compared to small-sized non-emaciated females. Concentrations of PCBs in liver increased from 1000 to 4000 ng/g lipid weight as the hepatic lipid content and the CF decreased. The inter-annual variation of EROD activity was associated with the variation in CF with lowest EROD activity and CF in 1999. When emaciated fish were excluded from the analyses, EROD activity was still lower (2-5-fold) in large compared to small fish and was no longer related to CF. For similar levels of CYP1A mRNA, EROD activity was lower in large compared to small fish. Thus, there was post-transcriptional inhibition of CYP1A activity in large-sized tomcod, indicative of cellular dysfunction. This response may be related to aging, chronic exposure to toxic contaminants or to selective pressures favoring less responsive individuals. This study demonstrates that fish age, size, and CF are important variables to consider in studies using EROD activity as an indicator of environmental contamination. The main finding was that a large part of the reduction of CYP1A with age in St. Lawrence Estuary tomcod was associated with severe emaciation of a large proportion of large-sized fish. Hepatic concentrations of contaminants covaried with the CF and the effects of these two variables on CYP1A could not be discriminated
— id: 44848, year: 2004, vol: 68, page: 233, stat: Journal Article,

Spatial variation in hepatic levels and patterns of PCBs and PCDD/Fs among young-of-the-year and adult Atlantic tomcod (Microgadus tomcod) in the Hudson River estuary
Fernandez, Marc P; Ikonomou, Michael G; Courtenay, Simon C; Wirgin, Isaac I
2004 Feb 15;38(4):976-983, Environmental science & technology
Full congener-specific polychorinated biphenyl (PCB) and partial-congener-specific polychorinated dibenzo-p-dioxin/furan (PCDD/F) analyses were performed on livers from young-of-the-year (YOY) and adult Atlantic tomcod from the Hudson River estuary including multiple sites along the main-stem Hudson River and Newark Bay/Hackensack River, NJ, and from a reference river, the Miramichi River, NB. Highest hepatic burdens of PCBs were found in fish collected in the main-stem Hudson River between river miles (RM) 37 and 50 and in Newark Bay/Hackensack River. By far, the highest concentrations of PCDD/Fs were seen in fish from Newark Bay/Hackensack River. The di- to tetrachlorinated biphenyls dominated the PCB composition in YOY tomcod, whereas the penta- to nonachlorinated biphenyls predominated in adults with particular prevalence of the 2,4,5-substituted diortho congeners. Overall, using a direct mixing model an aroclor composition of approximate 1:1:1, A1242:A1254:A1260, was calculated from the hepatic PCB profiles in YOY tomcod. A linear increase in A1242 characteristics with river mile was seen in YOY collected between RM 0 and RM 80, which was likely due to the well-characterized A1242 source from the former capacitor manufacturing plants located upriver. However, tomcod caught upstream of RM 80 exhibited a PCB pattern with decreasing A1242 characteristics, and it was hypothesized that this was due to the increased depuration or decreased uptake of low chlorinated (log K(OW) < 6) congeners upon entry of the fish into freshwater from brackish water. The most abundant tetra-octa PCDD/F chlorohomologue in tomcod collected from the main stem of the Hudson River was TCDF, whereas 2,3,7,8-TCDD was the major congener detected in tomcod from Newark Bay/Hackensack River, which showed elevated total PCDD/F levels compared to tomcod from the main-stem Hudson River
— id: 44849, year: 2004, vol: 38, page: 976, stat: Journal Article,

Origin and movements of young-of-the-year striped bass in the southern Gulf of St. lawrence, New Brunswick
Robinson, M; Courtenay, S; Benfey, T; Maceda, L; Wirgin, I
2004 MAR ;133(2):412-426, Transactions of the American Fisheries Society
Young-of-the-year (age-0) striped bass Morone saxatilis have been observed during late summer and fall in southern Gulf of St. Lawrence estuaries that may not support striped bass spawning. In this study, we tested the hypothesis that age-0 striped bass in the Richibucto and Kouchibouguac rivers disperse there from the Miramichi River, which is located approximately 35 km north of the Kouchibouguac River and 55 km north of the Richibucto River. Beach seining of the coastline between these three rivers during summer in 1997 and 1998 confirmed the presence of age-0 striped bass in the latter half of August but not before. Age-0 fish distributions over time were consistent with movement from the Miramichi River to the Kouchibouguac and Richibucto estuaries. Microsatellite nuclear DNA and mitochondrial DNA analyses were performed to determine the genetic relatedness among striped bass from these estuaries. Age-0 striped bass from the Shubenacadie River population in the Bay of Fundy, which is known to be genetically distinct from Gulf of St. Lawrence populations, and the Hudson River, New York, were used as out-groups in the analyses. In all comparisons, significant haplotype and allelic differences were found between Gulf of St. Lawrence samples and the Shubenacadie River and Hudson River populations. However, significant haplotype or allelic differentiation was rarely observed in comparisons among samples from rivers within the Gulf of St. Lawrence. These results suggest that some of the age-0 striped bass spawned in the Miramichi River leave their natal estuary in late summer and disperse through shallow coastal waters to other estuaries in the southern Gulf of St. Lawrence
— id: 42443, year: 2004, vol: 133, page: 412, stat: Journal Article,

Absence of shared mitochondrial DNA haplotypes between sea lamprey from North American and Spanish rivers
Rodriguez-Munoz, R; Waldman, JR; Grunwald, C; Roy, NK; Wirgin, I
2004 MAR ;64(3):783-787, Journal of fish biology
Sea lamprey Petromyzon marinus from the River Mino and Sella, Spain, showed an almost identical frequency for three observed haplotypes. None of these haplotypes were found among three North American populations. These results indicate an absence of exchange among sea lamprey populations spawning in the west and south-east Atlantic coasts. The similarity between the collections from the two Spanish rivers suggests that homing does not occur in anadromous sea lamprey. (C) 2004 The Fisheries Society of the British Isles
— id: 42469, year: 2004, vol: 64, page: 783, stat: Journal Article,

B[a]P-DNA binding in early life-stages of Atlantic tomcod: population differences and chromium modulation
Sorrentino, C; Roy, N K; Chambers, R C; Courtenay, S C; Wirgin, I
2004 Aug-Dec;58(2-5):383-388, Marine environmental research
Atlantic tomcod (Microgadus tomcod) from the Hudson River (HR) are resistant at the molecular and organismic levels to the effects of exposure to dioxin-like aromatic hydrocarbon (AH) compounds, but much less so to benzo[a]pyrene (B[a]P). The aims of this study were to determine in early life-stages of tomcod exposed to B[a]P: (1) if DNA binding levels differed between fish from the HR and Miramichi River (MR), and (2) if co-exposure to chromium could modulate this genotoxic effect. After exposure to [(3)H]B[a]P alone, DNA-bound radioactivity was 5-10-fold higher in embryos and larvae of MR than HR descent. Co-exposure to chromium modulated DNA binding levels in offspring of both populations. In MR embryos, co-exposure to chromium inhibited B[a]P uptake. These results demonstrated resistance to the genotoxic effects of B[a]P in early life stages of HR tomcod at an ecologically important endpoint and suggest the ability of chromium to modulate AH-induced genotoxicity
— id: 44847, year: 2004, vol: 58, page: 383, stat: Journal Article,

Mitochondrial DNA analysis indicates sea lampreys are indigenous to Lake Ontario
Waldman, JR; Grunwald, C; Roy, NK; Wirgin, II
2004 JUL ;133(4):950-960, Transactions of the American Fisheries Society
The parasitic sea lamprey Petromyzon marinus occurs throughout North America's Great Lakes, where it has an immense economic impact on commercially and recreationally important fishes. Sea lampreys indisputably invaded Lake Erie and the upper Great Lakes from Lake Ontario in the mid-1900s, but their official status as a normative species in Lake Ontario is based on circumstantial evidence and has long been subject to controversy. Presently, sea lampreys are considered by U.S. and Canadian government agencies to be an invasive species within the entire Great Lakes watershed, and millions of dollars are spent annually to suppress them. We sequenced 330 base pairs of the mitochondrial DNA control region of 224 sea lampreys collected from 10 locations (3 within the Lake Ontario drainage, 2 within the Lake Superior drainage, and 5 rivers between Quebec and New York that are tributary to the Atlantic Ocean). Eighteen haplotypes were revealed, of which 17 occurred in specimens from Atlantic coast rivers, 6 in specimens from Lake Ontario, and 2 in specimens from Lake Superior tributaries. Haplotype frequencies were not significantly different (P > 0.05) within regions, indicating low or no homing fidelity. But when haplotype frequencies were grouped within regions and compared along the hypothesized colonization pathway, significant differences were seen. Pronounced differences in haplotype frequency patterns between Atlantic coast and Lake Ontario drainage collections, together with arguments against the viability of canal passage, strongly support the idea of post-Pleistocene natural colonization by one of at least three hypothesized zoogeographic pathways. If sea lampreys are indigenous to Lake Ontario, management policies aimed toward intense suppression might need reevaluation
— id: 46569, year: 2004, vol: 133, page: 950, stat: Journal Article,

Development and use of a simple DNA test to distinguish larval redhorse species in the Oconee River, Georgia
Wirgin, I; Currie, DD; Stabile, J; Jennings, CA
2004 FEB ;24(1):293-298, North American journal of fisheries management
The robust redhorse Moxostoma robustum is a rare catostomid species that was recently 'rediscovered' in three Atlantic slope drainages in the southeastern United States, including the Oconee River, Georgia. Adult population size in the Oconee River is declining, and the population may be senescent due to recruitment failure. Evaluation of the environmental factors affecting the success of young life stages requires the ability to distinguish robust redhorse larvae from those of other redhorse species in the Oconee River. The use of morphological approaches, including size at collection date, have proven to be problematic in distinguishing larval robust redhorse from notchlip redhorse M. collapsum from the Oconee River. We developed a mitochondrial DNA (mtDNA) assay to distinguish between reference adults of these two redhorse species from the Oconee, Savannah, and Pee Dee rivers. This mtDNA assay was then applied to unknown larval redhorse collections from the Oconee River. In one collection, discordance was revealed in 40% of the individual larvae identified by both size at collection date and mtDNA. Of these, 75% of the fish thought to be notchlip redhorses based on size at date of collection exhibited robust redhorse mtDNA haplotypes. These results illustrate the utility of DNA techniques in characterizing the young life stages of fish and suggest that earlier surveys underestimated the abundance of larval robust redhorses in the Oconee River
— id: 42465, year: 2004, vol: 24, page: 293, stat: Journal Article,

Resistance to contaminants in North American fish populations
Wirgin, Isaac; Waldman, John R
2004 Aug 18;552(1-2):73-100, Mutation research
Fish from urban and industrialized estuaries are exposed among the highest levels of contaminants of any vertebrate populations. As a result, they serve as especially relevant models for determining the toxic effects and mechanisms through which environmental toxicants work. In controlled laboratory experiments, fish from highly contaminated locales sometimes exhibit resistance to contaminant-induced toxicity. Resistance may be due to genetic adaptation or physiological acclimations. Distinguishing between these possibilities is important in predicting the persistence of resistance and its potential costs to affected populations and communities. Along the Atlantic coast of North America, populations of two estuarine species, Atlantic killifish (mummichog) Fundulus heteroclitus and Atlantic tomcod Microgadus tomcod, exhibit phenotypes that are resistant to aromatic hydrocarbon (AH) contaminants, including polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polycyclic aromatic hydrocarbons (PAHs). Populations of these species exhibit resistance to AH-induced lethality, early life-stage toxicities, and expression of cytochrome P4501A (CYP1A). However, some differences among populations in the occurrence and type (genetic or physiological) of AH-resistant phenotypes have been observed. In some instances, resistance was obviously genetic and resulted in its transmission to at least the F2 generation, in others, resistance had a physiological or yet to be identified epigenetic basis. In some cases, resistance was observed for all AH compounds tested, in others, it was seen only for halogenated AHs. As toxic responses to AHs are believed to be mediated by the aryl hydrocarbon receptor pathway (AHR), several studies compared the structure and expression of AHR pathway molecules between resistant and sensitive fish populations. However, no obvious differences in these molecular parameters were observed between resistant and sensitive populations at the transcriptional level. Further studies at the protein level are recommended to further evaluate the role of the AHR pathway in conferring resistance. Open-ended microarray and proteomic approaches may provide additional resolution in determining the molecular mechanisms of resistance. Also, studies that evaluate the prevalence and ecosystem cost of resistance are needed
— id: 44846, year: 2004, vol: 552, page: 73, stat: Journal Article,

Population genetics of shortnose sturgeon Acipenser brevirostrum based on mitochondrial DNA control region sequences
Grunwald, C; Stabile, J; Waldman, J R; Gross, R; Wirgin, I
2002 Oct;11(10):1885-1898, Molecular ecology
Shortnose sturgeon is an anadromous North American acipenserid that since 1973 has been designated as federally endangered in US waters. Historically, shortnose sturgeon occurred in as many as 19 rivers from the St. John River, NB, to the St. Johns River, FL, and these populations ranged in census size from 10(1) to 10(4), but little is known of their population structure or levels of gene flow. We used the polymerase chain reaction (PCR) and direct sequence analysis of a 440 bp portion of the mitochondrial DNA (mtDNA) control region to address these issues and to compare haplotype diversity with population size. Twenty-nine mtDNA nucleotide-substitution haplotypes were revealed among 275 specimens from 11 rivers and estuaries. Additionally, mtDNA length variation (6 haplotypes) and heteroplasmy (2-5 haplotypes for some individuals) were found. Significant genetic differentiation (P < 0.05) of mtDNA nucleotide-substitution haplotypes and length-variant haplotypes was observed among populations from all rivers and estuaries surveyed with the exception of the Delaware River and Chesapeake Bay collections. Significant haplotype differentiation was even observed between samples from two rivers (Kennebec and Androscoggin) within the Kennebec River drainage. The absence of haplotype frequency differences between samples from the Delaware River and Chesapeake Bay reflects a probable current absence of spawning within the Chesapeake Bay system and immigration of fish from the adjoining Delaware River. Haplotypic diversity indices ranged between 0.817 and 0.641; no relationship (P > 0.05) was found between haplotype diversity and census size. Gene flow estimates among populations were often low (< 2.0), but were generally higher at the latitudinal extremes of their distribution. A moderate level of haplotype diversity and a high percentage (37.9%) of haplotypes unique to the northern, once-glaciated region suggests that northern populations survived the Pleistocene in a northern refugium. Analysis of molecular variance best supported a five-region hierarchical grouping of populations, but our results indicate that in almost all cases populations of shortnose sturgeon should be managed as separate units
— id: 39587, year: 2002, vol: 11, page: 1885, stat: Journal Article,

When the American sea sturgeon swam east
Ludwig, Arne; Debus, Lutz; Lieckfeldt, Dietmar; Wirgin, Isaac; Benecke, Norbert; Jenneckens, Ingo; Williot, Patrick; Waldman, John R; Pitra, Christian
2002 Oct 3;419(6906):447-448, Nature
The two species of Atlantic sea sturgeon on either shore of the North Atlantic, Acipenser sturio in Europe and A. oxyrinchus in North America, probably diverged with the closure of the Tethys Sea and the onset of the North Atlantic Gyre 15-20 million years ago, and contact between them was then presumably precluded by geographic distance. Here we present genetic, morphological and archaeological evidence indicating that the North American sturgeon colonized the Baltic during the Middle Ages and replaced the native sturgeon there, before recently becoming extinct itself in Europe as a result of human activities. In addition to representing a unique transatlantic colonization event by a fish that swims upriver to spawn, our findings have important implications for projects aimed at restocking Baltic waters with the European sturgeon
— id: 44850, year: 2002, vol: 419, page: 447, stat: Journal Article,

Cytochrome P4501A1 is induced by PCB 77 and benzo[a]pyrene treatment but not by exposure to the Hudson River environment in Atlantic tomcod (Microgadus tomcod) post-yolk sac larvae
Roy, Nirmal K; Courtenay, Simon; Maxwell, Grace; Yuan, Zhanpeng; Chambers, R Christopher; Wirgin, Isaac
2002 Mar-Apr;7(2):162-173, Biomarkers
In fish, the embryos and larvae are the life-stages most sensitive to damage from environmentally borne dioxin-like compounds and polycyclic aromatic hydrocarbons (PAHs). Methods are not routinely available to measure the body burdens of contaminants in embryos and larvae, thus precluding the investigation of links between exposure and biological effects. Quantification of expression of cytochrome P4501A1 (CYP1A1) provides an index of relative exposure of natural populations to bioavailable aromatic hydrocarbons (AH) and an initial evaluation of their biological effects. We developed a quantitative approach to standardize total RNA loading and then used competitive reverse transcriptase-polymerase chain reaction (RT-PCR) to quantify the CYP1A1 mRNA expression in environmentally exposed Atlantic tomcod (Microgadus tomcod) post yolk-sac larvae (postlarvae) from the Hudson River, New York, and in chemically treated postlarval offspring of controlled laboratory crosses of Hudson River parents. Significant induction of CYP1A1 expression was observed in tomcod postlarvae exposed to waterborne 3,3',4,4'-tetrachlorobiphenyl (PCB 77) (four-fold) and benzo[a]-pyrene (eight-fold) compared with vehicle-exposed controls. In contrast, CYP1A1 was not induced in Hudson River-exposed postlarvae compared with vehicle-exposed controls. This study demonstrates the feasibility of using competitive RT-PCR for the measurement of gene expression in environmentally exposed larvae of sentinel species, and is consistent with the hypothesis that postlarvae exposed to the Hudson River environment have not bioaccumulated sufficient levels of AHs to induce CYP1A1 expression. The high levels of hepatic CYP1A1 mRNA expression previously reported in 5-8 month old juvenile tomcod from the Hudson River coincides with their descent to the benthic habitat and the onset of independent feeding on AH-contaminated benthic prey
— id: 39620, year: 2002, vol: 7, page: 162, stat: Journal Article,

Impacts of life history and biogeography on the genetic stock structure of Atlantic sturgeon Acipenser oxyrinchus oxyrinchus, Gulf sturgeon A-oxyrinchus desotoi, and shortnose sturgeon A- brevirostrum
Waldman, JR; Grunwald, C; Stabile, J; Wirgin, I
2002 DEC ;18(4-6):509-518, Journal of applied ichthyology
Non-genetic data indicate that Atlantic sturgeon ( Acipenser oxyrinchus oxyrinchus) are substantially dispersive in marine waters, possibly remaining out of their natal rivers for many years at a time. Gulf sturgeon (A. o. desotoi) only appear to use marine waters during cooler months, summering in rivers. Shortnose sturgeon (A. brevirostrum) are highly residential in rivers, but do sometimes go to sea and move between rivers. We used the polymerase chain reaction (PCR) and direct sequence analysis of a portion of the mitochondrial DNA ( mtDNA) control region to examine stock structure, haplotypic diversity, and gene flow (N-fm) among these taxa, hypothesizing that gene flow would be highest in Atlantic sturgeon. Stock structuring was strong within all three taxa most river populations supported genetically distinct stocks of sturgeons. Estimates of gene flow among regions were low to moderate in comparison with other anadromous fishes, suggesting that homing fidelity within all three taxa is high. However, average gene flow in Atlantic sturgeon was almost three times higher than in shortnose sturgeon, which somewhat exceeded gene flow values for Gulf sturgeon. Levels and patterns of haplotype diversity differed dramatically between the largely-sympatric Atlantic and shortnose sturgeon. Atlantic sturgeon exhibited a cline in haplotype diversity with monomorphism or very low diversity observed in northern, previously glaciated populations and moderate to high levels of diversity in southern, non-glaciated populations. In contrast, no difference in haplotype diversity and little sharing of haplotypes was observed between northern and southern populations of shortnose sturgeon. We hypothesize that the greater mtDNA diversity in northern populations of shortnose sturgeon resulted from their use of a glacial refugium that was not occupied by Atlantic sturgeon. Gulf sturgeon show much lower gene flow than Atlantic sturgeon. This may be due to their more temporally and geographically constrained marine migrations, which may reduce the opportunities for straying, and a need to return to assured summer thermal refugia. A new finding is the probable existence of a native, genetically-distinct Atlantic sturgeon stock in the James River, which has rami cations for restoration strategies for the species in Chesapeake Bay
— id: 33274, year: 2002, vol: 18, page: 509, stat: Journal Article,

Comparison of mitochondrial DNA control region sequence and microsatellite DNA analyses in estimating population structure and gene flow rates in Atlantic sturgeon Acipenser oxyrinchus
Wirgin, I; Waldman, J; Stabile, J; Lubinski, B; King, T
2002 DEC ;18(4-6):313-319, Journal of applied ichthyology
Atlantic sturgeon Acipenser oxyrinchus is large, long-lived, and anadromous with subspecies distributed along the Atlantic ( A. oxyrinchus oxyrinchus) and Gulf of Mexico (A. o. desotoi) coasts of North America. Although it is not certain if extirpation of some population units has occurred, because of anthropogenic influences abundances of all populations are low compared with historical levels. Informed management of A. oxyrinchus demands detailed knowledge of its population structure, levels of genetic diversity, and likelihood to home to natal rivers. We compared the use of mitochondrial DNA ( mtDNA) control region sequence and microsatellite nuclear DNA (nDNA) analyses in identifying the stock structure and homing fidelity of Atlantic and Gulf coast populations of A. oxyrinchus. The approaches were concordant in that they revealed moderate to high levels of genetic diversity and suggested that populations of Atlantic sturgeon are highly structured. At least six genetically distinct management units were detected using the two approaches among the rivers surveyed. Mitochondrial DNA sequences revealed significant cline in haplotype diversity along the Atlantic coast with monomorphism observed in Canadian populations. High levels of nDNA diversity were also observed among populations along the Atlantic coast, including the two Canadian populations, probably resulting from the more rapid rate of mutational and evolutionary change at microsatellite loci. Estimates of gene flow among populations were similar between both approaches with the exception that because of mtDNA monomorphism in Canadian populations, gene flow estimates between them were unobtainable. Analyses of both genomes provided high resolution and confidence in characterizing the population structure of Atlantic sturgeon. Microsatellite analysis was particularly informative in delineating population structure in rivers that were recently glaciated and may prove diagnostic in rivers that are geographically proximal along the south Atlantic coast of the US
— id: 33273, year: 2002, vol: 18, page: 313, stat: Journal Article,

An evaluation of the etiology of reduced CYP1A1 messenger RNA expression in the Atlantic tomcod from the Hudson River, New York, USA, using reverse transcriptase polymerase chain reaction analysis
Roy NK; Courtenay S; Yuan Z; Ikonomou M; Wirgin I
2001 May;20(5):1022-1030, Environmental toxicology & chemistry
Adult Atlantic tomcod, Microgadus tomcod, from the Hudson River, New York State, USA, exhibit reduced inducibility of hepatic cytochrome P4501A1 (CYP1A1) mRNA compared with adult tomcod from the cleaner Miramichi River, New Brunswick, Canada, when treated with coplanar polychlorinated biphenyl (PCB) congeners or 2,3,7,8-tetrachlorodibenzo-p-dioxin. In contrast, little difference in CYP1A1 inducibility is observed between tomcod from these two rivers when treated with polycyclic aromatic hydrocarbons (PAHs). We sought to determine if impaired hepatic CYP1A1 inducibility in Hudson River tomcod results from a multigenerational, genetic adaptation or a single generational, physiological acclimation. Embryos and larvae from controlled experimental crosses of Hudson River and Miramichi River parents were exposed for 24 h to water-borne PCB congener 77 (10 ppm), benzo[a]pyrene (BaP; 10 ppm), or dimethysulfoxide, and CYP1A1 expression was assessed in individual larva using competitive reverse transcriptase polymerase chain reaction (RT-PCR) analysis. The CYP1A1 mRNA was significantly induced in larvae from both populations by BaP (47- and 52-fold) and PCB 77 (9- and 22-fold), although levels of expression were higher in offspring of Miramichi matings. Most important, CYP1A1 mRNA was significantly induced by PCB 77 in larvae from Hudson River parents. Concentrations of dioxin, furan, and PCB congeners were measured in livers and eggs of female tomcod from these two locales to quantify the extent of maternal transfer of contaminants. For both rivers, wet-weight contaminant concentrations were significantly higher (4-7 times) in livers than in eggs of the same females, suggesting that a threshold level of contaminants may have to be reached before CYP1A1 transcription is impaired. We conclude that reduced inducibility of hepatic CYP1A1 mRNA in adult tomcod from the Hudson River is most consistent with single-generational acclimation
— id: 20685, year: 2001, vol: 20, page: 1022, stat: Journal Article,

Morphological and genetic variation among shortnose sturgeon Acipenser brevirostrum from adjacent and distant rivers
Walsh, MG; Bain, MB; Squiers, T; Waldman, JR; Wirgin, I
2001 FEB ;24(1):41-48, Estuaries
Shortnose sturgeon, Acipenser brevirostrum, is a small, endangered species which occurs in 19 estuary systems along the east coast of North America. These populations are considered as separate entities by the U.S. National Marine Fisheries Service although evidence of morphologic or genetic differentiation among populations has not been documented. The purpose of this study was to compare morphological and genetic attributes among shortnose sturgeon collected From the Kennebec and Androscoggin Rivers, Maine, and the Hudson River, New York. Six morphometric and five meristic characteristics were quantified. Multivariate and univariate analyses of covariance and variance were used to assess differences among populations. Our analyses provided evidence for distinct populations in the Androscoggin and Kennebec Rivers, but character differentiation was greater between fish from these two locations and the Hudson River. Analysis of morphometric characters indicated significant differences in fish shape among the three rivers, with Hudson River sturgeon differing from the Maine rivers for the characters of head length, snout length, and mouth width. Significant differences were observed for meristic characters, but pairwise comparisons did not reflect a clear pattern of variability. Sequencing of a portion of the mitochondrial DNA control region revealed 15 haplotypes among 73 total specimens from the three rivers. Shortnose sturgeon from the Kennebec and Androscoggin Rivers were different from each other (p = 0.0260); both differed significantly (p < 0.0001) from the Hudson River collection. Gene flow was estimated at approximately 7 female migrants per generation between the two Maine populations and about 1 per generation between each of the Maine populations and the Hudson River population. Such strong stock structuring among presumably recently established post-Pleistocene (< 10,000 yr) populations suggests that this species occurs in highly discrete units, Morphological and genetic variation observed in this study combined with current knowledge of life history attributes of shortnose sturgeon indicate that conservative management decisions are necessary until the patterns and extent of differentiation among populations species-wide can be investigated further
— id: 55109, year: 2001, vol: 24, page: 41, stat: Journal Article,

Genetic divergence of robust redhorse Moxostoma robustum (Cypriniformes Catostomidae) from the Oconee River and the Savannah River based on mitochondrial DNA control region sequences
Wirgin, I; Oppermann, T; Stabile, J
2001 MAY 1 ;15(2):526-530, Copeia
A Memorandum of Understanding, which formed the Robust Redhorse Conservation Committee (RRCC), was developed and adopted by concerned stakeholders in Georgia, South Carolina, and North Carolina to attempt recovery of the recently 'rediscovered,' and rare, robust redhorse Moxostoma robustum, As part of the con servation program, genetic analyses of robust redhorse populations were needed to facilitate responsible hatchery programs that could be used to supplement natural reproduction in declining populations and to reestablish populations in rivers in which it may have historically been present. We analyzed mtDNA control region sequences in robust redhorse from the Oconee and Ocmulgee Rivers in the Altamaha River drainage and the Savannah River to determine the genetic relatedness of these populations to guide restoration efforts. Fixed differences in mtDNA haplotypes were found between robust redhorse from the two drainages that strongly argues for the designation of these populations as Evolutionarily Significant Units and against the interstock transfer of fish. Further studies will be needed to evaluate the full significance of these differences and associated management implications
— id: 55080, year: 2001, vol: 15, page: 526, stat: Journal Article,

Is hepatic cytochrome P4501A1 expression predictive of hepatic burdens of dioxins, furans, and PCBs in Atlantic tomcod from the Hudson River estuary?
Yuan Z; Wirgin M; Courtenay S; Ikonomou M; Wirgin I
2001 Oct;54(3-4):217-230, Aquatic toxicology
Hepatic cytochrome P4501A1 (CYP1A1) expression in fishes is frequently used to evaluate bioavailable aromatic hydrocarbon contamination of aquatic ecosystems. In controlled laboratory experiments, CYP1A1 expression in naive fishes is usually dose-responsive to aromatic hydrocarbons and in field studies levels of gene expression in natural populations often correspond with known levels of sediment-borne contaminants. We quantified CYP1A1 mRNA levels in juvenile Atlantic tomcod Microgadus tomcod from 42 sites in the Hudson River estuary to evaluate the correspondence between hepatic CYP1A1 expression and hepatic concentrations of persistent halogenated aromatic hydrocarbons and to determine the utility of CYP1A1 expression as a biomarker in evaluating the microgeographic distribution of bioavailable contaminants within a large aquatic ecosystem. We found significant spatial heterogeneity in CYP1A1 mRNA levels among collection sites with levels of gene expression differing in some cases by 23-34 folds. CYP1A1 mRNA expression was highest in tomcod from the Newark Bay complex and lowest in tomcod from the most upriver collection sites in the main stem of the Hudson River. Although levels of PCDDs, PCDFs, and PCBs expressed as TCDD TEQs and CYP1A1 mRNA were highest in tomcod from the Newark Bay complex, there was no relationship between hepatic halogenated aromatic hydrocarbon levels and hepatic CYP1A1 mRNA in tomcod from sites in the main stem of the Hudson River. These results suggest that levels of CYP1A1 expression in fish from sites highly polluted with mixtures of halogenated aromatic hydrocarbons and other xenobiotics may not always be reflective of levels of bioavailable aromatic hydrocarbon contaminants. Based on these results and earlier controlled laboratory experiments, we hypothesize that elevated levels of CYP1A1 expression in tomcod from the Hudson River may be due primarily to PAHs or other contaminants not measured in this study
— id: 26711, year: 2001, vol: 54, page: 217, stat: Journal Article,

Isolation of microsatellites in striped bass Morone saxatilis (Teleostei) and their preliminary use in population identification
Roy NK; MacEda L; Wirgin I
2000 Jun;9(6):827-829, Molecular ecology
— id: 11661, year: 2000, vol: 9, page: 827, stat: Journal Article,

Genetic structure of Atlantic sturgeon populations based on mitochondrial DNA control region sequences
Wirgin, I; Waldman, JR; Rosko, J; Gross, R; Collins, MR; Rogers, SG; Stabile, J
2000 MAR ;129(2):476-486, Transactions of the American Fisheries Society
The Atlantic sturgeon Acipenser oxyrinchus oxyrinchus has a latitudinally broad distribution along the east coast of North America, with extant populations occurring from the Saint Lawrence River to rivers in southern Georgia. This species once supported intensive caviar-based fisheries that resulted in overharvest and sharply reduced population abundances; presently, directed commercial fishing for Atlantic sturgeon is banned in U.S. waters. We sequenced a 203-base-pair section of the mitochondrial DNA (mtDNA) control region of 322 Atlantic sturgeon specimens from 11 river systems across their range to elucidate their stock structure. We found a pronounced latitudinal dine in the number of composite mtDNA haplotypes and in haplotypic diversity, which increased from north to south, from previously glaciated and subsequently recolonized systems to the portion of their range unglaciated during the Pleistocene. The observed number of haplotypes per population ranged from 1 haplotype in each of the two northernmost population samples to 17 in the sample from the Savannah River. Haplotypic diversity ranged from 0.0 to 0.90. The greater genetic diversity within and among southern populations is likely a product of the persistence of these populations through the Pleistocene and to the faster mutation rates associated with their shorter generation times. Of 39 composite mtDNA haplotypes found, 64% were unique to particular populations. Monomorphism of the two Canadian populations suggested a strong founder effect. Three haplotypes unique to northern populations were probably the result of base substitutions that occurred within the past 10,000 years. In contrast with an earlier study, we found stock structure among southern populations and evidence of at least seven generic stocks across this subspecies' range
— id: 54551, year: 2000, vol: 129, page: 476, stat: Journal Article,

A comparison of the dose and time response of CYP1A1 mRNA induction in chemically treated Atlantic tomcod from two populations
Courtenay, SC; Grunwald, CM; Kreamer, GL; Fairchild, WL; Arsenault, JT; Ikonomou, M; Wirgin, II
1999 OCT ;47(1):43-69, Aquatic toxicology
Quantification of cytochrome P4501A1 (CYP1A1) mRNA levels in environmentally exposed Atlantic tomcod (Microgadus tomcod) has revealed significantly induced gene expression in fish from contaminated locales including the Hudson River, New York, and the Miramichi River, New Brunswick. In order to calibrate this response, determine its sensitivity and dose-responsiveness, levels of hepatic CYP1A1 mRNA were quantified in depurated Atlantic tomcod intraperitoneally (i.p.) injected with various concentrations of: beta-naphthoflavone (beta-NF), the PAH benzo[a]pyrene (B[a]P), the non-ortho coplanar PCB congener-3,3',4,4'- tetrachlorobiphenyl (IUP
— id: 53918, year: 1999, vol: 47, page: 43, stat: Journal Article,

High frequency of K-ras mutations in pink salmon embryos experimentally exposed to Exxon Valdez oil
Roy, NK; Stabile, J; Seeb, JE; Habicht, C; Wirgin, I
1999 JUL ;18(7):1521-1528, Environmental toxicology & chemistry
Previous studies demonstrated reduced survivorship of pink salmon embryos from populations in Prince William Sound, Alaska, USA, that were exposed to Exxon Valdez-released oil compared with populations from matched nonoiled streams. Survivorship was also significantly decreased in embyros from lineages that were oiled in Prince William Sound and reared in clean water under controlled hatchery conditions compared with the descendants of nonoiled lineages. This suggests that the effect of oiling on pink salmon populations was persistent and could be transmitted intergenerationally. However, the ability of environmentally released oil to cause DNA sequence alterations in natural populations has vet to be demonstrated. We used polymerase chain reaction analysis to screen for alterations in the K-ras oncogene in DNA from pink salmon embryos that were exposed under controlled laboratory conditions to weathered Prudhoe Bay crude oil. Polymerase chain reaction and direct DNA sequence analyses were used to identify mutational hotspots within exons 1 and 2 of K-ras. and 3' primer mismatch analysis was used to determine the frequency of mutations in the 30 offspring of two families of pink salmon that were experimentally exposed to oiled or clean gravel. Mutations were only observed at codons 12, 13, and 61 of K-ras, sites that are frequently mutated in animal and human tumors. All mutations resulted in deduced amino acid substitutions. As expected, in all individuals exhibiting mutations, the copy number of the normal allele exceeded that of the mutated allele. The frequencies of mutations in oiled embryos at K-ras exons 1 and 2 were 68 and 41%, respectively. K-ras mutations were not observed in siblings that were exposed to clean gravel or in the parents of the two experimental matings. These results indicate that exposure of pink salmon embryos to weathered Prudhoe Bay crude oil under controlled laboratory conditions can elicit somatic cell mutations in high frequency at mutational hotspots in genes such as K-ras. However the frequency of these events in oiled natural populations of pink salmon and other vulnerable species in Prince William Sound and the heritability of these mutations within oiled lineages have yet to be evaluated
— id: 54023, year: 1999, vol: 18, page: 1521, stat: Journal Article,

Range-wide stock structure of Atlantic sturgeon Acipenser oxyrinchus oxyrinchus based on sequence analysis of mitochondrial DNA
Wirgin, Isaac I
[Tuxedo NY : Nelson Institute of Environmental Medicine], 1999,
— id: 1222, year: 1999, vol: , page: , stat: ,

Multiple population bottlenecks and DNA diversity in populations of wild striped bass, Morone saxatilis
Waldman, JR; Bender, RE; Wirgin, II
1998 JUL ;96(3):614-620, Fishery bulletin
Striped bass, Morone saxatilis, in the Coos River, Oregon, are derived from natural colonists from San Francisco Bay, which in turn were intentionally transplanted from the Hudson River. Because of founder effects, this unusually well-documented colonization sequence should have resulted in diminished genetic variability in the penultimate and ultimate populations, which may have been further compounded in the Coos River population by subsequent drastic reductions in its abundance. To test whether these sequential bottlenecks reduced genetic diversity we surveyed both nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) variation in the Coos River population and in both populations along the historical pathway that led to its founding. There was no evidence of reduced nDNA diversity among these populations at the three loci examined. However, the number of mtDNA haplotypes revealed decreased from 8 in the original Hudson River population, to 5 in the San Francisco Bay population, to only 1 in the Coos River population. This pattern of conserved nDNA diversity and reduced mtDNA diversity is consistent with a recent population bottleneck. Coos River striped bass have shown increasing levels of pathological hermaphroditism. We speculate that the reduced genetic diversity of the Coos River striped bass population may have led to a depensatory cascade involving hermaphroditism that inhibited reproduction and recruitment, followed by in creased levels of inbreeding as the population declined
— id: 53402, year: 1998, vol: 96, page: 614, stat: Journal Article,

Status and restoration options for Atlantic sturgeon in North America
Waldman, JR; Wirgin, II
1998 JUN ;12(3):631-638, Conservation biology
There is considerable interest in restoring stocks of Atlantic sturgeon (Acipenser oxyrinchus), one of only two dozen extant sturgeons worldwide. Populations of its two subspecies are found in large rivers along the North American coasts of the Atlantic (A. o. oxyrinchus) and the Gulf of Mexico (A. o. desotoi). Although these populations were severely reduced because of overfishing and, in some instances, blockage of spawning runs, their present statuses, vary from those that still support limited fisheries (St. John River, new Brunswick), to a large but apparently declining population (Hudson River), to relict-sized (Delaware River, Mobile River), to apparently extirpated (Maryland tributaries of Chesapeake Bay; St. Johns, river, Florida). There are two primary alternatives for restoring these populations: (1) eliminating harvest and allowing natural recolonization and increase and (2) hatchery-based stocking (reintroduction or supplementation). We performed genetic analyses aimed at guiding restoration efforts. Mitochondrial DNA analysis revealed strong stock structure along both coasts at eh regional and, in some instances, population levels. Estimates of gene flow rates were low and suggested slow natural recolonization rates. Thus, the first alternative avoids the genetic risks of interstock transfer and inbreeding depression that may result from hatchery-based programs, but given the low intrinsic rates of increases and recolonization of Atlantic sturgeon, recovery may take decades to centuries, if it occurs at all. Therefore,it is imperative that the restoration approach be tailored to the particular circumstances and demographics of each population; however, the characteristics of this species and poor funding prospects make this information difficult to obtain. It appears likely that initial Atlantic sturgeon stocking efforts will target systems where they are extinct, as recently occurred in the Nanticoke River of Chesapeake Bay
— id: 53435, year: 1998, vol: 12, page: 631, stat: Journal Article,

Altered gene expression and genetic damage in North American fish populations
Wirgin I; Waldman JR
1998 Mar 20;399(2):193-219, Mutation research
Populations of marine, estuarine, and freshwater fish from highly urban and industrialized sites in North America often exhibit elevated prevalences of neoplastic, preneoplastic, and nonneoplastic hepatic lesions, and sometimes epidermal neoplasms compared to conspecifics from more pristine reference locales. Positive statistical associations with environmental concentrations of PAHs and other xenobiotics and experimental laboratory studies suggest a chemical etiology to these epizootics. Studies have investigated the expression of carcinogenically relevant genes, the extent of overall DNA damage, somatic cell mutations, germ line polymorphisms, and overall levels of genetic diversity in fish from these populations and other polluted sites. In general, elevated levels of cytochrome P4501A expression have been found in fish from contaminated locales; however, inhibition of gene induction has been seen in hepatic lesions and in normal tissue in fish from the most contaminated sites, perhaps due to genetic adaptation or physiological acclimation. Levels of bulky hepatic DNA adducts, as detected by 32P-postlabeling, are almost always elevated in fish from populations that are exposed to highly contaminated environments. However, levels of DNA adducts were not always predictive of the vulnerability to neoplasia of populations and species from polluted sites. Elevated levels of oxygen radical-induced DNA damage have been observed in hepatic tumors, preneoplastic lesions, and normal livers in a single species of flatfish from contaminated sites; however, the prevalences of these alterations in other species and at other polluted sites has yet to be evaluated. Frequent alterations in the K-ras oncogene have been reported in hepatic neoplasms in several species from highly contaminated sites and also in embryos that were experimentally exposed to oil-contaminated sediments. Studies also suggest that heritable germ line polymorphisms, altered allelic frequencies, and reductions in overall genetic diversity may have occurred in some highly impacted populations; however, the origin and functional significance of altered allelic frequencies have largely yet to be evaluated. In summary, feral fish appear particularly sensitive to DNA alterations from xenobiotics, perhaps due to their unusually high levels of exposure, relatively inefficient DNA repair, and the high frequency of polyploidy in some taxa and provide excellent models to explore the relationships between xenobiotic exposure and altered gene structure and expression
— id: 57284, year: 1998, vol: 399, page: 193, stat: Journal Article,

Characterization of the aromatic hydrocarbon receptor gene and its expression in Atlantic tomcod
Roy NK; Wirgin I
1997 Aug 15;344(2):373-386, Archives of biochemistry & biophysics. ABB
Cytochrome P4501A1 (CYP1A1) mRNA is not inducible in Atlantic tomcod from the Hudson River that are treated with halogenated aromatic hydrocarbons (HAHs). In contrast, CYP1A1 mRNA is inducible in Hudson River tomcod that are treated with polycyclic aromatic hydrocarbons (PAHs) and in tomcod that are collected from cleaner rivers and treated with HAHs or PAHs. We hypothesize that CYP1A1 transcription is inhibited in Hudson River tomcod because of down-regulation of the aromatic hydrocarbon receptor (AhR) pathway and that separate molecular pathways modulate CYP1A1 transcription in fish treated with HAHs and PAHs. We initially evaluated levels of hepatic nuclear protein binding at enhancer elements (DREs) in the regulatory region of tomcod CYP1A1. No difference in levels of protein binding was observed between tomcod from the Hudson and Miramichi (cleaner) rivers that were untreated or were treated with benzo[a]pyrene. In contrast, levels of protein binding were lower in tomcod from the Hudson River that were treated with TCB than in similarly treated fish from the Miramichi River, suggesting differences between the populations in the structure or expression of AhR pathway molecules. To address this possibility, AhR DNA sequences were characterized from tomcod cDNA and genomic DNA libraries. In tomcod and mammals, AhR is represented by 11 exons, overall peptide sizes are similar, and amino acid sequences at basic, helix-loop-helix, PAAS A, and PAAS B domains are highly conserved. In contrast, little similarity was observed between tomcod and mammals in the sizes or sequences of AhR exons 10 and 11, including the absence in tomcod of glutamine-rich domains. No differences in levels of hepatic AhR mRNA were observed between the two populations or treatment groups when tomcod were untreated or were treated with aromatic hydrocarbons. In contrast, variation in levels of AhR mRNA expression was observed among tomcod tissues; however, no relationship was observed between levels of AhR mRNAs and CYP1A1 mRNAs in tissues from chemically or vehicle control-treated fish. RFLP analysis revealed extensive variation in exons 10 and 11 of AhR cDNA among tomcod from different rivers. Our results suggest that variation between tomcod populations in CYP1A1 mRNA inducibility is reflected by differences in levels of inducible hepatic protein binding to DREs. However, levels of hepatic AhR mRNA are not down-regulated in the Hudson River population, are not affected by AH treatments, and levels of AhR mRNA expression are not responsible for the differential inducibility of CYP1A1 transcription
— id: 56984, year: 1997, vol: 344, page: 373, stat: Journal Article,

Effects of the antibiotic Baytril (enrofloxacin) on PCB-initiated induction of cytochrome P4501A mRNA in sexually mature Atlantic tomcod (Microgadus tomcod)
Williams, J; Courtenay, SC; Wirgin, II
1997 FEB ;16(2):241-244, Environmental toxicology & chemistry
We used a factorial experimental design to determine whether the antimicrobial Baytril (enrofloxacin) had an effect on induction of cytochrome P4501A (CYP1A) mRNA in Atlantic tomcod. Fish were injected with corn oil, Baytril and corn oil, Baytril and 3,3',4,4'-tetrachlorobiphenyl (PCB) dissolved in corn oil, or just PCB in corn oil. Analysis of gene induction in both sexes considered together showed significant induction by PCB treatment and a significant effect of sex (males higher than females). Because the experiment was carried out just before spawning, our results provide additional evidence for pretranslational suppression of CYP1A induction in spawning females. Separate analysis of the sexes showed that in both males and females, PCB had a significant effect on induction. However, in analyzing the males we also observed significant induction by Baytril alone. In addition, the BaytrilPCB combination resulted in the highest induction in any group. These findings demonstrate the potential for confounding results due to exposure of sampled fish to antibiotics, either in a laboratory or field situation
— id: 53268, year: 1997, vol: 16, page: 241, stat: Journal Article,

An evaluation of introgression of Atlantic coast striped bass mitochondrial DNA in a Gulf of Mexico population using formalin-preserved museum collections
Wirgin I; Maceda L; Stabile J; Mesing C
1997 Oct;6(10):907-916, Molecular ecology
Striped bass Morone saxatilis populations in drainages along the Gulf of Mexico coast (Gulf) were depleted in the 1950s and 1960s, probably because of anthropogenic influences. It is believed that only the Apalachicola-Chattahoochee-Flint (A-C-F) river system continually supported a naturally reproducing population of Gulf lineage. Striped bass juveniles of Atlantic coast (Atlantic) ancestry were introduced to restore population abundances in the A-C-F from the late 1960s to the mid 1970s and in many other Gulf rivers from the 1960s to the present. We previously identified mtDNA polymorphisms that were unique to approximately 60% of striped bass from the A-C-F and which confirmed the continued successful natural reproduction of striped bass of Gulf maternal ancestry within the system. However, the genetic relatedness of the extant A-C-F population to 'pure' Gulf striped bass was not addressed. In this study, we determined the frequency of a diagnostic mtDNA XbaI polymorphism in samples of 'pure' Gulf striped bass that were collected from the A-C-F prior to the introduction of Atlantic fish, that were obtained from museum collections, and that were originally preserved in formalin. PCR primers were developed that allowed for amplification of a 191-bp mtDNA fragment that contained the diagnostic XbaI restriction site. Using RFLP and direct sequence analyses of the PCR amplicons, we found no significant differences in mtDNA XbaI genotype frequencies between the archived samples and extant A-C-F samples collected over a 15-year period. This indicates that significant maternally mediated introgression of Atlantic mtDNA genomes into the A-C-F gene pool has not occurred. Additionally, we found no evidence of the unique Gulf mtDNA genotype in striped bass from extant populations in Texas, Louisiana and the Mississippi River. These results highlight the importance of the A-C-F as a repository of striped bass to restore extirpated Gulf populations and the potential use of museum collections in retrospective population studies
— id: 57351, year: 1997, vol: 6, page: 907, stat: Journal Article,

Mixed-stock analysis of Atlantic coast striped bass (Morone saxatilis) using nuclear DNA and mitochondrial DNA markers
Wirgin, II; Waldman, JR; Maceda, L; Stabile, J; Vecchio, VJ
1997 DEC ;54(12):2814-2826, Canadian journal of fisheries & aquatic sciences
Striped bass (Morone saxatilis) stocks comingle along the northeastern United States and Canadian coasts and support mixed-stock fisheries in which stock compositions fluctuate widely. Many approaches to stock analysis of these populations have been tried. The recent use of mitochondrial DNA (mtDNA) haplotype frequency data showed promising results, despite low levels of mtDNA variation; to improve resolution, we used a single-copy nuclear DNA (nDNA) probe with mio mtDNA markers (major length variants and Tag I variants), alone or in combination. Striped bass reference collections were from the Hudson River and Chesapeake Bay, and mixed-stock collections (1989 and 1991) were from eastern Long Island, New York. The combination of the nDNA and mtDNA major length variant data provided lower but still quite high resolution potential (D-st = 0.417) in mixed-stock analysis (1991 collection) than the combination of all three markers (D-st = 0.552). However, unlike the Hudson River stock, the Chesapeake Bay stock is composed of multiple substocks that vary significantly in the frequencies of Taq I variants; this among-substock variation destabilizes the Chesapeake Bay reference data set and the resultant mixed-stock estimates. Thus, we recommend an approach based on composite nDNA and mtDNA major length variant markers
— id: 53542, year: 1997, vol: 54, page: 2814, stat: Journal Article,

Molecular analysis in the conservation of sturgeons and paddlefish
Wirgin, Isaac I.; Stabile, Joseph E.; Waldman, John R.
1997 ;48(1-4):385-398, Environmental Biology of Fishes
Sturgeon and paddlefish populations worldwide have declined because of anthropogenic influences. The structure and magnitude of genetic diversity of natural populations serves to buffer these fishes against environmental variation and should be maintained. Modern molecular biological techniques provide the ability to sensitively characterize and quantify the extent of genetic variation in natural populations. We provide a summary of those problems in sturgeon population biology that are amenable to investigation with DNA approaches, and their applications to date. These have included genetic identification and discrimination of taxa, identification of hybrids, stock identification, mixed-stock analysis, and estimation of gene flow and homing fidelity. To date, almost all studies have been restricted to North American fauna. Improvements to these technologies, including nondestructive sampling, should permit more widespread application of molecular approaches to problems of acipenseriform conservation. We suggest that the use of more sensitive molecular tools such as analyses of hypervariable repetitive and non-coding single copy nuclear DNA may assist management even in those taxa which exhibit overall low levels of genetic diversity
— id: 98800, year: 1997, vol: 48, page: 385, stat: Journal Article,

Genetic divergence between Acipenser oxyrinchus oxyrinchus and A-o-desotoi as assessed by mitochondrial DNA sequencing analysis
Ong, TL; Stabile, J; Wirgin, I; Waldman, JR
1996 MAY 16 ;32(2):464-469, Copeia
— id: 52895, year: 1996, vol: 32, page: 464, stat: Journal Article,

Characterization of CYP1A1 gene regulatory elements in cancer-prone Atlantic tomcod
Roy NK; Konkle B; Wirgin I
1996 Jun;6(3):273-277, Pharmacogenetics
— id: 56890, year: 1996, vol: 6, page: 273, stat: Journal Article,

Stock structure and homing fidelity in Gulf of Mexico sturgeon (Acipenser oxyrinchus desotoi) based on restriction fragment length polymorphism and sequence analyses of mitochondrial DNA
Stabile J; Waldman JR; Parauka F; Wirgin I
1996 Oct;144(2):767-775, Genetics
Efforts have been proposed worldwide to restore sturgeon populations through the use of hatcheries to supplement natural reproduction and to reintroduce sturgeon where they have become extinct. We examined the population structure and inferred the extent of homing in the anadromous Gulf of Mexico (Gulf) sturgeon (Acipenser oxyrinchus desotoi). Restriction fragment length polymorphism and control region sequence analyses of mitochondrial DNA (mtDNA) were used to identify haplotypes of Gulf sturgeon specimens obtained from eight drainages spanning the subspecies' entire distribution from Louisiana to Florida. Significant differences in haplotype frequencies indicated substantial geographic structuring of populations. A minimum of four regional or river-specific populations were identified (from west to east): (1) Pearl River, LA and Pascagoula River, MS, (2) Escambia and Yellow rivers, FI, (3) Choctawbatchee River, FL and (4) Apalachicola Ochlockonee, and Suwannee rivers, FL. Estimates of maternally mediated gene flow between any pair of the four regional or river-specific stocks ranged between 0.15 to 1.2. Tandem repeats in the mtDNA control region of Gulf sturgeon were not perfectly conserved. This result, together with an absence of heteroplasmy and length variation in Gulf sturgeon mtDNA, indicates that the molecular mechanisms of mtDNA control region sequence evolution differ among acipenserids
— id: 12528, year: 1996, vol: 144, page: 767, stat: Journal Article,

Stock composition of the New York Bight Atlantic sturgeon fishery based on analysis of mitochondrial DNA
Waldman, JR; Hart, JT; Wirgin, II
1996 MAY ;125(3):364-371, Transactions of the American Fisheries Society
One of the few remaining fisheries for Atlantic sturgeon Acipenser oxyrinchus takes place during spring and fall in the New York Eight, but no information on the stock composition of this fishery is available. We used data from mitochondrial DNA (mtDNA) restriction fragment length polymorphism analysis to estimate the relative contributions of source stocks of Atlantic sturgeon to a New York Eight fishery sample (N = 112) collected in 1993 and 1994. Composite mtDNA haplotype frequencies of source populations were first characterized with five informative restriction enzymes: Bgl I, Msp I, EcoR V, HinfI, and Hinc II. All St. Lawrence River, Quebec, and St. John River, New Brunswick, specimens had an identical haplotype (genotypic diversity = 0.0); for the purposes of mixed-stock analysis, both populations were pooled as the ''Canadian stock.'' Genotypic diversity ranged between 0.483 and 0.750 among samples from the Hudson River in New York, the Edisto River in South Carolina, and the Ogeechee, Altamaha, and Satilla rivers in Georgia. Chi-square analyses indicated that the Edisto, Savannah (Georgia), Ogeechee, Altamaha, and Satilla River samples should be grouped as the ''southeastern stock,'' and that haplotype frequencies of the three source stocks (Canadian, Hudson River, southeastern) were highly heterogeneous (P = 0.0000). Mixed-stock analysis with a constrained least-squares approach under the conditional method indicated a 97.2% Hudson River contribution, a 2.8% contribution by the southeastern stock, and a 0.0% contribution by the Canadian stock; the unconditional method provided estimates of 99.1%, 0.9%, and 0.0%, respectively. Frequencies of mtDNA haplotypes of subadults (N = 30) from a seasonal aggregation of Atlantic sturgeon from the lower Delaware River were intermediate between those of the Hudson River and southeastern stocks. This finding, together with ancillary information, suggests that the Delaware River aggregation is primarily either a mixture of both the Hudson River and southeastern stocks or of the Hudson River stock and a relict Delaware River stock
— id: 52922, year: 1996, vol: 125, page: 364, stat: Journal Article,

Genetic differentiation of three key anadromous fish populations of the Hudson River
Waldman, JR; Nolan, K; Hart, J; Wirgin, II
1996 DEC ;19(4):759-768, Estuaries
Large, recreationally or commercially important populations of Atlantic sturgeon (Acipenser oxyrinchus), American shad (Alosa sapidissima), and striped bass (Morons saxatilis) occur in the Hudson River. Members of the Hudson River populations of these fishes also occur over a broad range along the Atlantic coast where they mix with conspecifics from other anadromous populations. For management purposes, it is imperative to be able to discriminate among individual stocks so that weak stocks may be protected and harvest may be allocated equitably. Because of their sensitivity and resistance to environmentally-induced temporal variation, molecular approaches have been increasingly employed in stock identification studies. However, post-Pleistocene recolonization of the Hudson River must have occurred less than 10,000 years ago-a relatively brief period for genetic divergence among populations. We tested whether various measures of DNA variation between Hudson River populations and adjacent populations of Atlantic sturgeon, American shad, and striped bass were sufficient to discriminate among their conspecific populations. American shad populations surveyed for mtDNA variation were highly diverse genotypically, but genotypic frequencies among the populations of the Connecticut, Hudson, and Delaware rivers were statistically homogeneous (p > 0.05). In contrast, Atlantic sturgeon (surveyed for mtDNA variation) and striped bass (surveyed for mtDNA and nuclear DNA variation) populations of the Hudson River were not genotypically diverse, but they were differentiated from northern and southern populations. Our results suggest higher gene flow (and lesser homing fidelity) among American shad populations in comparison with the two other species
— id: 53286, year: 1996, vol: 19, page: 759, stat: Journal Article,

A comparison of cytochrome P4501A (CYP1A) mRNA inducibility in four species of Atlantic coast anadromous fishes
Wirgin, I; Konkle, B; Pedersen, M; Grunwald, C; Williams, J; Courtenay, SC
1996 DEC ;19(4):913-922, Estuaries
Quantification of levels of cytochrome P4501A (CYP1A) gene expression in sentinel species of fishes has been proposed as a management tool to evaluate contamination of aquatic systems. Based on preliminary studies, we hypothesized that differences in CYP1A mRNA inducibility among individuals, populations, or species might lead to spurious conclusions when using this approach in environmental monitoring programs. To address this possibility, we quantitated and compared CYP1A mRNA induction levels in four species of common Atlantic Coast estuarine fish: smooth flounder, hogchoker, striped bass, and Atlantic tomcod, which were treated with model chemicals (beta naphthoflavone (beta-NF), or benzo[a]pyrene at 10 ppm) known to induce CYP1A mRNA, or were exposed to contaminated environments. Species-specific CYP1A DNA probes were generated from PCR (polymerase chain reaction) amplification of genomic DNA using conserved oligonucleotide primers, and, along with cloned rainbow trout and Atlantic tomcod CYP1A cDNA probes were used to quantify CYP1A mRNA levels in northern blot analyses. Successful PCR amplification of CYP1A hybridizable DNA fragments was observed for all four species. Results from northern blot analyses showed large differences in CYP1A mRNA induction among species; only Atlantic tomcod exhibited significant induction of CYP1A mRNA for both chemically treated (97-fold) and environmentally exposed fish (34-fold). Significant, although lower, levels of induction were observed in beta-NF treated (14-fold) smooth flounder, but not in environmentally exposed smooth flounder. Only low levels (not significant) of CYP1A gene induction were detected in hogchokers and striped bass. We conclude that CYP1A mRNA inducibility differed significantly among fish taxa perhaps due to differences in regulation of gene expression, suggesting that careful selection of sentinel species should be exercised prior to the use of CYP1A mRNA induction in environmental monitoring programs. However, the significance of differences in CYP1A mRNA inducibility in relation to higher level biological endpoints has yet to be determined
— id: 53287, year: 1996, vol: 19, page: 913, stat: Journal Article,

A COMPARISON OF RT-PCR AND NORTHERN BLOT ANALYSIS IN QUANTIFYING METALLOTHIONEIN MESSENGER-RNA LEVELS IN KILLIFISH EXPOSED TO WATERBORNE CADMIUM
KAPLAN, LAE; VANCLEEF, K; WIRGIN, I; CRIVELLO, JF
1995 APR ;39(1-4):137-141, Marine environmental research
Reverse transcriptase PCR (RT-PCR) was evaluated as an alternative to Northern blot analysis in quantifying levels of metallothionein (MT) mRNA. Killifish were exposed to water-borne cadmium (Cd) at concentrations ranging from 0 ppb to 46 ppb and their levels of hepatic MT mRNA were quantitated by both Northern blot analysis and RT-PCR. Both methods provided comparable results in that low constitutive levels of MT mRNA were observed in fish exposed to clean water, dose-responsiveness was seen in fish exposed to increasing concentrations of Cd, and sensitivities of both techniques were similar in detecting induced levels of MT mRNA in Cd exposed fish. These results suggest that RT-PCR may provide a sensitive and quantitative method to evaluate gene expression in fish from small, non-invasively sampled tissues
— id: 87374, year: 1995, vol: 39, page: 137, stat: Journal Article,

Characterization and prevalence of a polymorphism in the 3' untranslated region of cytochrome P4501A1 in cancer-prone Atlantic tomcod
Roy NK; Kreamer GL; Konkle B; Grunwald C; Wirgin I
1995 Sep 10;322(1):204-213, Archives of biochemistry & biophysics. ABB
Atlantic tomcod (Microgadus tomcod) from the cancer-prone Hudson River population exhibit a genetic polymorphism in the cytochrome P4501A (CYP1A) gene which is evidenced in Northern blot analyses by a truncated transcript and in Southern blot analyses by a deletion in the variant allele. To initially evaluate the functional significance of this polymorphism, we sought to characterize the molecular basis for this polymorphism and to determine its frequency in tomcod from other populations in which the prevalence of neoplasia is low. The common CYP1A allelic sequence was determined from beta-naphthoflavone-induced tomcod cDNA and from tomcod genomic DNA. A sequence of the variant CYP1A allele was obtained by direct sequence analysis of the amplicons of variant tomcod cDNA and genomic DNA. CYP1A exon and intron structure is highly conserved between tomcod and all other teleost and mammalian species compared. Similarity of the deduced tomcod, rainbow trout, and plaice amino acid sequences was 72%, whereas similarity between tomcod and mammalian sequences was approximately 50%. The variant tomcod CYP1A allele results from a 606-bp deletion in the 7th exon of the 3' untranslated region (UTR) of the cDNA. Polymerase chain reaction and Northern blot analyses revealed an absence of this CYP1A polymorphism in tomcod from other rivers. Studies in humans suggest that variation in CYP1A1 cDNA may impact on genetic susceptibility to environmentally induced neoplasia. Furthermore, studies in in vitro mammalian models indicate the importance of 3' UTRs on gene expression by impacting on the stability of transcript. These results suggest that the 3' UTR CYP1A polymorphism in tomcod may have consequences for the genetic susceptibility of Hudson River fish to hepatic neoplasia
— id: 56842, year: 1995, vol: 322, page: 204, stat: Journal Article,

MITOCHONDRIAL-DNA STABILITY AND STRIPED BASS STOCK IDENTIFICATION - COMMENT
WALDMAN, JR; WIRGIN, II
1995 NOV ;124(6):954-956, Transactions of the American Fisheries Society
— id: 52667, year: 1995, vol: 124, page: 954, stat: Journal Article,

MIXED-STOCK ANALYSIS OF STRIPED BASS IN 2 RIVERS OF THE BAY OF FUNDY AS REVEALED BY MITOCHONDRIAL-DNA
WIRGIN, I; JESSOP, B; COURTENAY, S; PEDERSEN, M; MACEDA, S; WALDMAN, JR
1995 MAY ;52(5):961-970, Canadian journal of fisheries & aquatic sciences
Mark-recapture studies have shown that striped bass from the Hudson River and Chesapeake Bay migrate to the Bay of Fundy and its tributaries during spring and summer. The objective of this study was to determine the relative contributions of U.S. stocks and the endemic Shubenacadie River population to the adult striped bass aggregations that occurred during 1992 and 1993 in two rivers of the Bay of Fundy: the Saint John River, New Brunswick (where striped bass spawning may not presently occur), and the Shubenacadie River, Nova Scotia (where striped bass spawning occurs). Mitochondrial DNA genotype frequency data were used in a mixture model. Up to 97% of adults from the Saint John River were determined to be of U.S. origin, whereas less than 10% of adult striped bass collected in the Shubenacadie River were migrants from U.S. stocks. Consequently, we suggest that efforts to maintain or restore the Saint John River population with native broodstock may be unsuccessful owing to possible extinction of the native stock; however, protection of the Shubenacadie River spawning stock should be enhanced
— id: 86731, year: 1995, vol: 52, page: 961, stat: Journal Article,

Genetic and molecular ecotoxicology: a research framework
Anderson, S; Sadinski, W; Shugart, L; Brussard, P; Depledge, M; Ford, T; Hose, J; Stegeman, J; Suk, W; Wirgin, I
1994 Dec;102 Suppl 12:3-8, Environmental health perspectives
Participants at the Napa Conference on Genetic and Molecular Ecotoxicology assessed the status of this field in light of heightened concerns about the genetic effects of exposure to hazardous substances and recent advancements in our capabilities to measure those effects. We present here a synthesis of the ideas discussed throughout the conference, including definitions of important concepts in the field and critical research needs and opportunities. While there were many opinions expressed on these topics, there was general agreement that there are substantive new opportunities to improve the impact of genetic and molecular ecotoxicology on prediction of sublethal effects of exposure to hazardous substances. Future studies should emphasize integration of genetic ecotoxicology, ecological genetics, and molecular biology and should be directed toward improving our understanding of the ecological implications of genotoxic responses. Ecological implications may be assessed at either the population or ecosystem level; however, a population-level focus may be most pragmatic. Recent technical advancements in measuring genetic and molecular responses to toxicant exposure will spur rapid progress. These new techniques have considerable promise for increasing our understanding of both mechanisms of toxicity on genes or gene products and the relevance of detrimental effects to individual fitness
— id: 132244, year: 1994, vol: 102 Suppl 12, page: 3, stat: Journal Article,

Assessment of within-group variation in CYP1A mRNA inducibility in environmentally exposed and chemically treated Atlantic tomcod
Courtenay S; Williams PJ; Grunwald C; Konkle B; Ong TL; Wirgin II
1994 Dec;102 Suppl 12:85-90, Environmental health perspectives
CYP1A gene expression has been implicated in the processing of environmental procarcinogens and levels of variation in CYP1A mRNA expression are high in both environmentally exposed and chemically treated Atlantic tomcod. The objective of this study was to evaluate the effects of physical and biological parameters such as temperature, sex, and reproductive state on within-group variation in CYP1A mRNA induction. Levels of variation in CYP1A mRNA expression were directly correlated with mean levels of gene induction. Our results indicate that sex and reproductive state, but not temperature, had significant effects on CYP1A mRNA inducibility in tomcod; however, these parameters did not account for all interindividual variation in CYP1A inducibility. Other intrinsic biological factors, such as genetic polymorphisms in molecular pathways leading to CYP1A induction, may contribute to the high levels of interindividual variation in CYP1A inducibility in Atlantic tomcod
— id: 6597, year: 1994, vol: 102 Suppl 12, page: 85, stat: Journal Article,

Use of DNA analysis in the management of natural fish populations
Waldman, John R; Wirgin, Isaac
Molecular environmental biology Boca Raton FL : Lewis Publishers, 1994,
— id: 4285, year: 1994, vol: , page: ?, stat: Chapter,

ORIGIN OF THE PRESENT DELAWARE RIVER STRIPED BASS POPULATION AS SHOWN BY ANALYSIS OF MITOCHONDRIAL-DNA
WALDMAN, JR; WIRGIN, II
1994 JAN ;123(1):15-21, Transactions of the American Fisheries Society
Management options for the Delaware River population of striped bass Morone saxatilis depend on whether or not the population forms a discrete stock. The recent increase in striped bass in the Delaware River follows decades of scarcity and concern about the possible extinction of the original population. The increase may have resulted from one or more of the following: expansion of a remnant population, repopulation by migrants from the Chesapeake Bay, or repopulation by migrants from the Hudson River. To determine the origin of the present Delaware River striped bass population, we analyzed mitochondrial DNA (mtDNA) from 191 striped bass collected in the Delaware River between 1990 and 1992. Our results indicate the Delaware River striped bass population is genetically intermediate between the Chesapeake Bay and Hudson River populations; mtDNA major-length genotype frequencies of the Delaware River sample were significantly different (P < 0.05) from those of the Hudson River stock, whereas mtDNA minor-length genotype frequencies of the Delaware River sample differed significantly from those of the Chesapeake Bay stock (P < 0.005). This intermediacy, together with information from historical surveys that suggest the original population did not become extinct, favors the hypothesis that the present Delaware River striped bass stock represents expansion from the original Delaware River stock
— id: 52598, year: 1994, vol: 123, page: 15, stat: Journal Article,

A biomarker approach to assessing xenobiotic exposure in Atlantic tomcod from the North American Atlantic coast
Wirgin II; Grunwald C; Courtenay S; Kreamer GL; Reichert WL; Stein JE
1994 Sep;102(9):764-770, Environmental health perspectives
We determined levels of hepatic cytochrome P4501A (CYP1A) mRNA, hepatic DNA adducts, and fluorescent aromatic compounds (FACs) in bile, a measure of exposure to polyaromatic hydrocarbons, in Atlantic tomcod from six river systems ranging from highly polluted to relatively pristine on the northeast North American coast (the Hudson River, New York; the St. Lawrence River, Quebec; the Miramichi River, New Brunswick; the Saco and Royal rivers, Maine; and the Margaree River, Nova Scotia). Hudson River tomcod showed the greatest response for all parameters, and tomcod from the Margaree River exhibited the least response. Tomcod from the Miramichi River exhibited marked induction of CYP1A mRNA but low levels of hepatic DNA adducts and biliary FACs, whereas fish from the St. Lawrence River showed no induction of CYP1A mRNA and moderately elevated levels of DNA adducts and biliary FACs. In tomcod from the Hudson and Miramichi rivers, the levels of CYP1A mRNA were 28 times and 14 times, respectively, as great as the levels in fish from the St. Lawrence, Saco/Royal, and Margaree rivers. Mean levels of DNA adducts varied from 120 nmol adducts/mol bases in Hudson River tomcod to < 3 nmol adducts/mol bases in fish from the Miramichi and Margaree rivers. Concentrations of FACs in the bile of tomcod from the Hudson and St. Lawrence rivers were 8 and 1.8 times, respectively, as great as the concentrations in tomcod from the Miramichi River and Margaree River. In tomcod from the Hudson River, all three biomarkers were markedly elevated; in the St. Lawrence River two biomarkers were elevated, in the Miramichi River one was elevated, but no biomarker was substantially elevated in fish from the Saco/Royal and Margaree rivers. Elevated levels of hepatic DNA adducts and biliary FACs in tomcod from the Hudson River suggest increased exposure to PAHs, consistent with previous studies
— id: 8419, year: 1994, vol: 102, page: 764, stat: Journal Article,

WHAT DNA CAN DO FOR YOU
WIRGIN, II; WALDMAN, JR
1994 JUL ;19(7):16-27, Fisheries
Many problems in fisheries science require markers to discriminate among individuals, populations, or species and to monitor representatives of these groupings through time. The nucleotide sequences of DNA typically offer more than 3 billion potentially informative markers-many orders of magnitude more than alternative approaches. Molecular techniques, once tedious, have advanced so that rapidly analyzing the numerous samples typically required to resolve fisheries problems is now possible. To date, most molecular analyses in fisheries science have focused on analysis of mitochondrial DNA (mtDNA), but newer approaches involving nuclear DNA (nDNA) show great promise. In particular, noncoding single copy nDNA may be more informative than mtDNA analyses for anadromous and marine species, in which low genetic diversity is frequently encountered. In this paper, we outline 12 categories of fisheries problems amenable to molecular approaches and provide a review of the structure and analysis of DNA, the nature of DNA variation in fishes, and the modes of analysis most suitable for particular questions. The future should witness the routine implementation of these techniques; such efforts would be enhanced by increased communication between managers and researchers, centralization of facilities, and standardization of nomenclature
— id: 52421, year: 1994, vol: 19, page: 16, stat: Journal Article,

Assessment of environmental degradation by molecular analysis of a sentienel species : Atlantic tomcod
Wirgin, Isaac I; Garte, Seymour J
Molecular environmental biology Boca Raton FL : Lewis Publishers, 1994,
— id: 4286, year: 1994, vol: , page: ?, stat: Chapter,

Racial differences in restriction fragment length polymorphisms and messenger RNA inducibility of the human CYP1A1 gene
Cosma G; Crofts F; Currie D; Wirgin I; Toniolo P; Garte SJ
1993 Jan-Feb;2(1):53-57, Cancer epidemiology biomarkers & prevention
Recent studies have examined the relationship between genetic polymorphisms of the human cytochrome P-4501A1 (CYP1A1) gene and lung cancer susceptibility. We have quantified genotypic frequencies and measured gene expression in the CYP1A1 gene within racially diverse groups in order to determine the relationship between genotype and transcriptional regulation of the CYP1A1 gene. Lymphocytes were obtained from 68 individuals of European-American, African-American, and Asian descent, and CYP1A1 gene inducibility was measured in mitogen-stimulated cells. CYP1A1 gene inducibility was significantly lower in African-Americans than in European-Americans or Asians, while several other population parameters were found to have no effect on gene expression levels. Restriction fragment length polymorphism analysis of lymphocyte DNA following MspI restriction enzyme digestion revealed a significant difference in the frequencies of CYP1A1 genotypes between European-Americans and Asians. The only homozygous variants detected were of Asian descent. The frequencies of CYP1A1 genotypes in all races conformed to Hardy-Weinberg genotypic equilibrium. When CYP1A1 gene inducibility was compared to CYP1A1 genotype, no significant correlations were found. These studies, along with our previous survey of CYP1A1 gene expression in creosote-exposed workers, add further support to the use of CYP1A1 gene inducibility as a potential marker of polycyclic aromatic hydrocarbon exposure in human populations
— id: 10391, year: 1993, vol: 2, page: 53, stat: Journal Article,

INDUCTION AND CLEARANCE OF CYTOCHROME P4501A MESSENGER-RNA IN ATLANTIC TOMCOD CAGED IN BLEACHED KRAFT MILL EFFLUENT IN THE MIRAMICHI RIVER
COURTENAY, S; GRUNWALD, C; KREAMER, GL; ALEXANDER, R; WIRGIN, I
1993 DEC ;27(3-4):225-243, Aquatic toxicology
Levels of cytochrome P4501A mRNA were measured in Atlantic tomcod caged in the effluents of a bleached kraft pulp and paper mill on the Miramichi River, NB, Canada and two sites downstream, and compared to levels in fish caged upstream of the mill and in unexposed laboratory-maintained tomcod. Additionally, the rate of clearance of CYP1A mRNA in tomcod exposed at the mill and transferred to clean water was compared to that observed in tomcod treated in the laboratory with a single dose of 2, 3, 7, 8-TCDD (0.5 mu g/kg). Levels of CYP1A mRNA in tomcod caged upriver of the mill were low and comparable to those observed in untreated laboratory control fish. Levels of CYP1A mRNA were elevated up to 11-fold in tomcod caged at the mill site and a gradient in levels of gene expression was seen at the two downstream sites. Tomcod i.p. injected with a single dose of 2, 3, 7, 8-TCDD exhibited a profile of prolonged CYP1A mRNA induction of at least 25 days. Levels of CYP1A mRNA in tomcod caged at the mill site and transferred to clean water remained significantly induced for at least 3 days post-transfer. In combination, these results suggest that CYP1A mRNA was induced in caged tomcod by constituents of the mill's effluents and that the rates of clearance of CYP1A mRNA may provide additional information concerning the identity of environmental inducers
— id: 52592, year: 1993, vol: 27, page: 225, stat: Journal Article,

Glial fibrillary acidic protein (GFAP) indicates in vivo exposure to environmental contaminants: PCBs in the Atlantic tomcod
Evans HL; Little AR; Gong ZL; Duffy JS; Wirgin I; el-Fawal HA
1993 May 28;679:402-406, Annals of the New York Academy of Sciences
— id: 13157, year: 1993, vol: 679, page: 402, stat: Journal Article,

USE OF MITOCHONDRIAL-DNA POLYMORPHISMS TO ESTIMATE THE RELATIVE CONTRIBUTIONS OF THE HUDSON RIVER AND CHESAPEAKE BAY STRIPED BASS STOCKS TO THE MIXED FISHERY ON THE ATLANTIC COAST
WIRGIN, I; MACEDA, L; WALDMAN, JR; CRITTENDEN, RN
1993 SEP ;122(5):669-684, Transactions of the American Fisheries Society
Restriction fragment length polymorphism (RFLP) analysis of mitochondrial DNA (mtDNA) was used to characterize stocks of striped bass Morone saxatilis and to estimate their relative contributions during the fall of 1989 to the mixed coastal fishery at eastern Long Island, New York. Mitochondrial DNA was obtained from reference samples of striped bass collected during the spring of 1989 from the Hudson River, New York, and four spawning areas of the Chesapeake Bay (Choptank, Rappahannock, and Potomac rivers and the upper Chesapeake Bay). Five mtDNA major length genotypes were detected in these fish, and significant differences in their frequencies were observed between the Hudson River and Chesapeake Bay samples. An mtDNA minor length genotype found in some fish (13%) from the Chesapeake Bay and absent from all Hudson River samples provided a second discriminatory character. By using a constrained generalized least squares approach, we estimated that the Hudson River and Chesapeake Bay stocks contributed 73% (95% confidence interval 50-87%) and 27% (95% confidence interval 13-51%) respectively, of the mixed fishery sample. The probability of the Hudson River contribution exceeding the Chesapeake Bay contribution in this sample was more than 95%. These results suggest that the Hudson River contribution to the mixed coastal fishery was greater in 1989 than reported in earlier studies. We also found no differences in mtDNA major length genotype frequencies among as many as 11 year-classes within the Hudson River, Chesapeake Bay, or Roanoke River spawning systems. These results indicate that mtDNA RFLP genotypes in these striped bass stocks are temporally stable within a fisheries context. An advantage to mtDNA analysis over phenotypic approaches is that, because mtDNA genotype frequencies are not subject to environmentally induced variation, efforts subsequent to an initial survey can focus on characterizing the mixed coastal fishery
— id: 52153, year: 1993, vol: 122, page: 669, stat: Journal Article,

MITOCHONDRIAL-DNA VARIATION IN STRIPED BASS (MORONE-SAXATILIS) FROM CANADIAN RIVERS
WIRGIN, II; ONG, TL; MACEDA, L; WALDMAN, JR; MOORE, D; COURTENAY, S
1993 JAN ;50(1):80-87, Canadian journal of fisheries & aquatic sciences
Mitochondrial DNA (mtDNA) was analyzed to determine the genetic relatedness of striped bass (Morone saxatilis) populations in tributaries to the Gulf of St. Lawrence and the Bay of Funday. Mitochondrial DNA genotype frequencies were determined for striped bass from the Shubenacadie River (Bay of Fundy) and the Miramichi and Tabusintac rivers (Gulf of St. Lawrence). These mtDNA genotype frequencies were compared with those of striped bass representative of the Atlantic coastal migratory stock originating in the Hudson River and Chesapeake Bay. Differences in the frequencies of mtDNA length variants permitted discrimination of the Shubenacadie River from the Miramichi River and Tabusintac River populations and all three Canadian populations from the U.S. spawned coastal migratory stock. No difference in the frequency of mtDNA length variants was observed between Tabusintac River and Miramichi River striped bass. Heteroplasmy for mtDNA length variants was observed in 35% of Gulf of St. Lawrence fish, the highest frequency observed in any striped bass population. These results highlight the genetic heterogeneity of these Canadian striped bass populations and their distinctiveness from U.S. stocks. Future efforts to restore these depleted Canadian striped bass populations should consider the impact of stock transfer on endemic striped bass gene pools
— id: 52274, year: 1993, vol: 50, page: 80, stat: Journal Article,

Use of cellular oncogene probes to identify Morone hybrids
Wirgin II; Maceda L; Mesing C
1992 Sep-Oct;83(5):375-382, Journal of heredity
We tested the ability of cellular oncogene (c-onc) probes to identify F1 hybrids and the lineage of known backcrosses within the fish genus Morone. Total DNA was isolated from five to 14 individuals per North American Morone species (striped bass, white bass, white perch, and yellow bass). The DNA was digested with two restriction enzymes, Eco RI and Hin dIII, Southern blotted, and hybridized to six different c-onc probes including v-abl, v-erb B, c-myc, c-H-ras, c-K-ras, and v-src. We found fixed genotypic differences among the four species for all six probes in single restriction enzyme digests. The heritability of these nuclear DNA genotypes was evaluated in hatchery-produced F1 Morone hybrids (striped bass x white bass and striped bass x white perch) tested with the six informative single probe/restriction enzyme combinations. All F1 individuals exhibited heterozygosity in all diagnostic nuclear DNA fragments, confirming the Mendelian inheritance of these genotypes in these fish. Furthermore, analysis of these nuclear DNA genotypes in hatchery-produced backcrosses of F1 hybrids striped bass x (white bass x striped bass) detected both recombinant and parental genotypes at all six polymorphic c-onc sequences. The lineage of suspected Morone hybrids of unknown descent collected from Lewis Smith Lake, Alabama, and from the Occoquan River, Virginia, was determined using the c-onc probes. Our results suggest that c-onc probes are suitable markers to unequivocally identify F1 hybrids and backcrosses and to quantify introgression in natural populations of fishes. The addition of RFLP analysis of mtDNA provided a complete ancestral history of individual fish
— id: 13463, year: 1992, vol: 83, page: 375, stat: Journal Article,

EFFECTS OF PRIOR EXPOSURE HISTORY ON CYTOCHROME-P4501A MESSENGER-RNA INDUCTION BY PCB CONGENER-77 IN ATLANTIC TOMCOD
WIRGIN, II; KREAMER, GL; GRUNWALD, C; SQUIBB, K; GARTE, SJ; COURTENAY, S
1992 DEC ;34(1-4):103-108, Marine environmental research
Levels of P4501A mRNA in tomcod collected from the Miramichi River, Canda and the Hudson River, New York were measured by slot blot analyses after the fish had been depurated and ip. injected with Aroclor 1254, PCB congener 77, or PCB congener 105. Elevated expression of P4501A mRNA was observed in congener 77-treated Miramichi tomcod, whereas no induction was seen in the Hudson River fish. Tom cod from both rivers were induced by injection with beta-naphthoflavone. These results suggest that the prior exposure history of the Hudson River tomcod may have affected their non-inducibility by treatment with PCB congener 77
— id: 51812, year: 1992, vol: 34, page: 103, stat: Journal Article,

Cytochrome P450IA mRNA expression in feral Hudson River tomcod
Kreamer GL; Squibb K; Gioeli D; Garte SJ; Wirgin I
1991 Jun;55(1):64-78, Environmental research
We sought to determine if levels of cytochrome P450IA gene expression are environmentally induced in feral populations of Hudson River tomcod, a cancer prone fish, and whether laboratory exposure of tomcod to artificially spiked and naturally contaminated Hudson sediments can elicit a significant response. Using Northern blot analysis, we found levels of P450IA mRNA in tomcod collected from two Hudson River sites higher than those in tomcod from a river in Maine. Depuration of environmentally induced Hudson tomcod P450IA mRNA was rapid, with an initial detectable decline in P450 gene expression by 8 hr and basal levels reached by 5 days. Intraperitoneal injection of beta-napthoflavone in depurated Hudson tomcod resulted in a 15-fold induction of P450 gene expression within 26 hr. Exposure of depurated Hudson tomcod to natural sediment spiked with two PAHs resulted in a 7-fold induction of P450 gene expression. Exposure of depurated tomcod to sediment from a contaminated Hudson site also resulted in a 7- to 15-fold induction of P450IA mRNA expression. Northern blot analysis revealed a second polymorphic cytochrome P450IA mRNA band in some tomcod which was also detected by Southern blot analysis. Induction of cytochrome P450IA mRNA in Atlantic tomcod may provide a sensitive biomarker of environmentally relevant concentrations of some pollutants in the Hudson and other northeastern tidal rivers
— id: 14008, year: 1991, vol: 55, page: 64, stat: Journal Article,

DISCRIMINATION AMONG ATLANTIC COAST POPULATIONS OF AMERICAN SHAD (ALOSA-SAPIDISSIMA) USING MITOCHONDRIAL-DNA
Nolan, K; Grossfield, J; Wirgin, I
1991 Sep;48(9):1724-1734, Canadian journal of fisheries & aquatic sciences
We used restriction endonuclease analysis of mitochondrial DNA (mtDNA) to differentiate among spawning stocks of American shad (Alosa sapidissima). Highly purified mtDNA was isolated from shad from four major spawning rivers: the St. John's (Florida), the Delaware, and the Hudson in the United States and the Miramichi in New Brunswick, Canada. Primarily four- and-five-base-cutting restriction enzymes were used to prepare both individual enzyme profiles and composite genotypes. Three separate spawning stocks, St. John's, Delaware-Hudson, and Miramichi, could be distinguished based on frequency differences in mtDNA genotypes generated by single restriction enzyme digests. We could not distinguish Delaware from Hudson River shad. Only a single definitive restriction site polymorphism was observed among all samples, but polyacrylamide gel electrophoretic mobility variants were common. Eco RI, Dde I, and Rsa I revealed stock-specific mtDNA genotypes. The frequencies of some genotypes occurred in latitudinal clines. Fifty-seven of 81 fish showed individual-specific composite genotypes. Geographic partitioning of genotypes suggests that mtDNA analysis may be useful for the identification of some American shad stocks and their relative contributions to mixed coastal fisheries
— id: 32149, year: 1991, vol: 48, page: 1724, stat: Journal Article,

GENETIC-POLYMORPHISM OF CYTOCHROME P-450IA IN CANCER-PRONE HUDSON RIVER TOMCOD
Wirgin, I; Kreamer, GL; Garte, SJ
1991 Jun;19(3):205-214, Aquatic toxicology
Messenger RNA and genomic DNA from Atlantic tomcod (Microgadus tomcod) from the cancer prone Hudson River population and two rivers in Maine were screened for size polymorphisms in cytochrome P-450IA. In northern blot analysis, we found that approximately 10% (16 of 176) of Hudson tomcod exhibited a polymorphism in P-450IA hybridizable mRNA not seen in any tomcod from Maine. All tomcod displayed a 3.0 kb P-450IA mRNA while variant individuals exhibited an additional 2.2 kb P- 450IA mRNA band. Southern blot analysis on these same fish confirmed the genetic basis of this polymorphism. All individuals exhibited a single P-450IA hybridizable DNA fragment while tomcod with the variant genotype also displayed a second smaller (< 1 kb) DNA fragment. The results of multiple restriction enzyme digests on these DNA's suggest that this polymorphism represents a second smaller P-450IA allele in these fish. This is the first demonstration of multiple forms of the cytochrome P-450IA gene in any species of fish
— id: 32169, year: 1991, vol: 19, page: 205, stat: Journal Article,

USE OF DNA FINGERPRINTING IN THE IDENTIFICATION AND MANAGEMENT OF A STRIPED BASS POPULATION IN THE SOUTHEASTERN UNITED-STATES
Wirgin, II; Grunwald, C; Garte, SJ; Mesing, C
1991 May;120(3):273-282, Transactions of the American Fisheries Society
Historically, striped bass Morone saxatilis were indigenous to many major drainages of the Gulf of Mexico (Gulf). It is believed that almost all natural populations were depleted by the 1950s and 1960s with the exception of fish in the Apalachicola-Chattahoochee-Flint (A-C-F) river system in northwestern Florida, Georgia, and Alabama. Striped bass of Atlantic ancestry were introduced into the A-C-F system during the 1960s and 1970s to enhance population size. We compared DNA fingerprints of striped bass collected from four Atlantic river systems with those of fish from the A-C-F system to determine if genetic differences still exist. Moderate levels of polymorphism were observed with two probes, the bacteriophage M-13 genome and mouse sequences related to the Drosophila Per gene. Striped bass DNA digested with single restriction enzymes and hybridized to these two probes generated single DNA fragments shared by 71 out of 75 A-C-F fish but not seen in any of 51 Atlantic fish. Heritability of DNA fingerprints was demonstrated from hatchery-raised fish of known parents. We believe that descendants of a genetically distinct ancestral Gulf population of striped bass still exist in the A-C-F and that efforts to maintain the genetic integrity of this population are warranted. Screening of potential A-C-F hatchery brood stock may be used to both maintain the genetic integrity of the Gulf strain and maximize its genetic diversity
— id: 32163, year: 1991, vol: 120, page: 273, stat: Journal Article,

DEVELOPMENT AND USE OF STRIPED BASS-SPECIFIC RFLP PROBES
WIRGIN, II; MACEDA, L
1991 DEC ;39(1):159-167, Journal of fish biology
— id: 52121, year: 1991, vol: 39, page: 159, stat: Journal Article,

Ha-ras oncogene mutations in cell lines derived from rat tracheal implants exposed in vivo to 7,12-dimethylbenz[a]anthracene
Cosma, G N; Wirgin, I I; Marchok, A C; Garte, S J
1990 ;3(5):258-263, Molecular carcinogenesis
The frequency of Ha-ras mutations was determined as a function of neoplastic progression in cell lines derived from rat tracheal implants exposed in vivo to 7,12-dimethylbenz[a]anthracene. Restriction fragment-length polymorphism (RFLP) analysis revealed an A----T transversion in the second base of codon 61 in 2 of 11 cell lines. One of the positive cell lines was tumorigenic, but the other was neither tumorigenic nor anchorage independent, thus indicating a lack of correlation between neoplastic stage and ras mutation. Densitometry analysis of the RFLP bands indicated that approximately 50% of the cells within these two heterogeneous populations contained the mutation. Direct sequence analysis of polymerase chain reaction-amplified DNA confirmed these results and did not reveal any other mutations in this region of the Ha-ras gene
— id: 132246, year: 1990, vol: 3, page: 258, stat: Journal Article,

Genetic diversity at an oncogene locus and in mitochondrial DNA between populations of cancer-prone Atlantic tomcod
Wirgin, I I; D'Amore, M; Grunwald, C; Goldman, A; Garte, S J
1990 Oct;28(9-10):459-475, Biochemical genetics
It has been reported that Atlantic tomcod (Microgadus tomcod) from the Hudson River exhibit an extremely high incidence of liver tumors. More than 90% of spawning 2-year-old fish display hepatocellular carcinomas. In contrast, representatives of this species from a relatively pristine environment show a much lower incidence of tumors. Genomic DNA and mitochondrial DNA (mtDNA) were isolated from tomcod from the Hudson River, New York, and the Saco River and Royal River, Maine. We found a statistically significant difference in the frequency of PstI-generated restriction fragment length polymorphisms in the abl cellular oncogene between Hudson and Maine tomcod. Allelic variation was observed at two of the three abl domains scored. A single composite genotype seen in approximately 40% of Hudson River fish was seen in only one Maine fish. This polymorphism enabled us to differentiate a Hudson River population from that encountered in the Maine rivers. This is the first demonstration of a population-specific polymorphism at a cellular oncogene locus in any species. In contrast, no restriction site polymorphisms were seen in mtDNA between the populations. The lack of mtDNA diversity in these fish is consistent with the geological history of the area. In combination, these results suggest that the genetic diversity observed at the c-abl oncogene locus must have been a fairly recent event and that oncogene loci may be particularly sensitive to mutational change
— id: 132245, year: 1990, vol: 28, page: 459, stat: Journal Article,

Activation of the K-ras oncogene in liver tumors of Hudson River tomcod
Wirgin I; Currie D; Garte SJ
1989 Dec;10(12):2311-2315, Carcinogenesis
Adult Atlantic tomcod collected from the Hudson River slightly north of New York City have an extremely high incidence (55-90%) of histologically defined hepatocellular carcinomas, whereas tomcod from control sites in Maine or Rhode Island exhibit little evidence of this condition. Genomic DNA was isolated from Hudson tomcod tumors and from normal Hudson and Saco River, Maine tomcod livers and tested for transforming activity in the NIH3T3 transfection assay. Six out of nine tumors (66%) tested proved positive. Southern blot analysis of all primary (6/6) transfectant and nude mouse tumor DNAs revealed evidence of an exogenous tomcod K-ras gene, while no activation of the H-ras gene was observed. These studies demonstrate that an outbred population of fishes and inbred mammals suffer genetic alternations at the same oncogene loci and suggest that similar pathways to neoplasia may be operative in both systems. Oncogene activation in naturally exposed feral populations may prove a particularly sensitive marker of environmental degradation in aquatic systems
— id: 10404, year: 1989, vol: 10, page: 2311, stat: Journal Article,

Detection of novel non-ras oncogenes in rat nasal squamous cell carcinomas
Hochwalt AE; Wirgin I; Felber M; Currie DD; Garte SJ
1988 ;1(1):4-6, Molecular carcinogenesis
Rat nasal squamous cell carcinomas induced by inhalation of three direct-acting alkylating agents yielded DNA containing activated oncogenes with no homology to any member of the ras family. The novel NIH 3T3 transforming oncogenes from tumors induced by beta-propiolactone and methylmethane sulfonate are distinct from each other based on restriction analysis. The gene isolated from beta-propiolactone-induced tumors is between 6 and 9 kb in size. None of the tumors induced by dimethylcarbamyl chloride contained positive DNA in the NIH 3T3 focus assay or in the nude mouse cotransfection assay. The rat nasal tumor model is apparently ideally suited for analysis of the roles of carcinogen and tissue specificity in oncogene activation, especially related to novel (non-ras) transforming oncogenes
— id: 11280, year: 1988, vol: 1, page: 4, stat: Journal Article,

ACTIVATION OF NOVEL ONCOGENES IN RAT NASAL CARCINOMAS INDUCED BY ALKYLATING-AGENTS
Hochwalt, AE; Wirgin, I; Garte, SJ
1988 Mar;29(5):137-137, Proceedings (American Association for Cancer Research)
— id: 31482, year: 1988, vol: 29, page: 137, stat: Journal Article,

Molecular evolution in the fish genus Morone
Wirgin, Isaac I
[S.l. : s.n.], 1987,
Thesis (Ph.D.) -- City University of New York, 1987
— id: 1221, year: 1987, vol: , page: , stat: ,