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Environmental Research Jan 2024Chinook salmon (Oncorhynchus tshawytscha) along the west coast of North America have experienced significant declines in abundance and body size over recent decades due...
Polychlorinated biphenyl and polybrominated diphenyl ether profiles vary with feeding ecology and marine rearing distribution among 10 Chinook salmon (Oncorhynchus tshawytscha) stocks in the North Pacific Ocean.
Chinook salmon (Oncorhynchus tshawytscha) along the west coast of North America have experienced significant declines in abundance and body size over recent decades due to several anthropogenic stressors. Understanding the reasons underlying the relatively high levels of persistent organic pollutants (POPs) in Chinook stocks is an important need, as it informs recovery planning for this foundation species, as well for the Chinook-dependent Resident killer whales (Orcinus orca, RKW) of British Columbia (Canada) and Washington State (USA). We evaluated the influence of stock-related differences in feeding ecology, using stable isotopes, and marine rearing ground on the concentrations and patterns of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in Chinook salmon. A principal components analysis (PCA) revealed a clear divergence of PCB and PBDE congener patterns between Chinook with a nearshore rearing distribution ('shelf resident') versus a more offshore distribution. Shelf resident Chinook had 12-fold higher PCB concentrations and 46-fold higher PBDE concentrations relative to offshore stocks. Shelf resident Chinook had PCB and PBDE profiles that were heavier and dominated by more bioaccumulative congeners, respectively. The higher δC and δN in shelf resident Chinook compared to the offshore rearing stocks, and their different marine distributions explain the large divergence in contaminant levels and profiles, with shelf resident stocks being heavily influenced by land-based sources of industrial contamination. Results provide compelling new insight into the drivers of contaminant accumulation in Chinook salmon, raise important questions about the consequences for their health, and explain a major pathway to the heavily POP-contaminated Resident killer whales that consume them.
Topics: Animals; Polychlorinated Biphenyls; Salmon; Halogenated Diphenyl Ethers; Pacific Ocean; Whale, Killer; British Columbia
PubMed: 37879388
DOI: 10.1016/j.envres.2023.117476 -
Environmental Health Perspectives Apr 2024Environmental pollutants, including polychlorinated biphenyls (PCBs) have been implicated in the pathogenesis of liver disease. Our group recently demonstrated that...
BACKGROUND
Environmental pollutants, including polychlorinated biphenyls (PCBs) have been implicated in the pathogenesis of liver disease. Our group recently demonstrated that PCB126 promoted steatosis, hepatomegaly, and modulated intermediary metabolism in a rodent model of alcohol-associated liver disease (ALD).
OBJECTIVE
To better understand how PCB126 promoted ALD in our previous model, the current study adopts multiple omics approaches to elucidate potential mechanistic hypotheses.
METHODS
Briefly, male C57BL/6J mice were exposed to polychlorinated biphenyl (PCB) 126 or corn oil vehicle prior to ethanol (EtOH) or control diet feeding in the chronic-binge alcohol feeding model. Liver tissues were collected and prepared for mRNA sequencing, phosphoproteomics, and inductively coupled plasma mass spectrometry for metals quantification.
RESULTS
Principal component analysis showed that PCB126 uniquely modified the transcriptome in EtOH-fed mice. EtOH feeding alone resulted in differentially expressed genes (DEGs), and PCB126 exposure resulted in more DEGs in the EtOH-fed group (907 DEGs) in comparison with the pair-fed group (503 DEGs). Top 20 significant gene ontology (GO) biological processes included "peptidyl tyrosine modifications," whereas top 25 significantly decreasing GO molecular functions included "metal/ion/zinc binding." Quantitative, label-free phosphoproteomics and western blot analysis revealed no major significant PCB126 effects on total phosphorylated tyrosine residues in EtOH-fed mice. Quantified hepatic essential metal levels were primarily significantly lower in EtOH-fed mice. PCB126-exposed mice had significantly lower magnesium, cobalt, and zinc levels in EtOH-fed mice.
DISCUSSION
Previous work has demonstrated that PCB126 is a modifying factor in metabolic dysfunction-associated steatotic liver disease (MASLD), and our current work suggests that pollutants also modify ALD. PCB126 may, in part, be contributing to the malnutrition aspect of ALD, where metal deficiency is known to contribute and worsen prognosis. https://doi.org/10.1289/EHP14132.
Topics: Male; Mice; Animals; Multiomics; Mice, Inbred C57BL; Ethanol; Liver; Polychlorinated Biphenyls; Fatty Liver; Liver Diseases, Alcoholic; Environmental Pollutants; Zinc; Tyrosine
PubMed: 38619879
DOI: 10.1289/EHP14132 -
Ecotoxicology and Environmental Safety Oct 2021Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were investigated in muscle samples from common...
Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were investigated in muscle samples from common kestrels (Falco tinnunculus), eagle owls (Bubo bubo), and little owls (Athene noctua) collected in Beijing, China. The concentrations of PCDD/Fs were in the ranges of 22.7-5280, 67.5-1610, and 68.4-3180 pg/g lipid weight (lw), while levels of dioxin-like PCBs ranged from 4.91 to 1560, 8.08-294, and 28.2-3540 ng/g lw, in common kestrel, eagle owl, and little owl, respectively. The main PCDD/Fs congener was 2,3,4,7,8-PeCDF, and CB-153 dominated the seven indicator PCBs. PCB levels have shown a decreasing trend in the last decade for the common kestrel, but not for little owl in Beijing, which exhibited higher levels of pollutants and toxic equivalency (TEQ) values than the other two species. Concentrations of PCDD/Fs, dioxin-like PCBs, and indicator PCBs differed between fledgling and adult raptors for certain species. Raptors in this study generally had a higher TEQ than the no-observed-effect level in the literature, indicating significant exposure risks to PCDD/Fs and dioxin-like PCBs in raptors, especially in adult little owls.
Topics: Animals; China; Dibenzofurans; Dibenzofurans, Polychlorinated; Dioxins; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Raptors
PubMed: 34352580
DOI: 10.1016/j.ecoenv.2021.112541 -
Toxicological Sciences : An Official... Jun 2022Exposure to environmental toxicants during preconception has been shown to affect offspring health and epigenetic mechanisms such as DNA methylation are hypothesized to...
Exposure to environmental toxicants during preconception has been shown to affect offspring health and epigenetic mechanisms such as DNA methylation are hypothesized to be involved in adverse outcomes. However, studies addressing the effects of exposure to environmental toxicants during preconception on epigenetic changes in gametes are limited. The objective of this study is to determine the effect of preconceptional exposure to a dioxin-like polychlorinated biphenyl (3,3',4,4',5-pentachlorobiphenyl [PCB126]) on DNA methylation and gene expression in testis. Adult zebrafish were exposed to 3 and 10 nM PCB126 for 24 h and testis tissue was sampled at 7 days postexposure for histology, DNA methylation, and gene expression profiling. Reduced representation bisulfite sequencing revealed 37 and 92 differentially methylated regions (DMRs) in response to 3 and 10 nM PCB126 exposures, respectively. Among them, 19 DMRs were found to be common between both PCB126 treatment groups. Gene ontology (GO) analysis of DMRs revealed that enrichment of terms such as RNA processing, iron-sulfur cluster assembly, and gluconeogenesis. Gene expression profiling showed differential expression of 40 and 1621 genes in response to 3 and 10 nM PCB126 exposures, respectively. GO analysis of differentially expressed genes revealed enrichment of terms related to xenobiotic metabolism, oxidative stress, and immune function. There is no overlap in the GO terms or individual genes between DNA methylation and RNA sequencing results, but functionally many of the altered pathways have been shown to cause spermatogenic defects.
Topics: Animals; DNA; DNA Methylation; Male; Polychlorinated Biphenyls; Testis; Zebrafish
PubMed: 35477799
DOI: 10.1093/toxsci/kfac044 -
Toxicology Apr 2017Exposure to environmental toxicants namely polychlorinated biphenyls (PCBs) is correlated with multiple health disorders including liver and cardiovascular diseases. The...
Exposure to environmental toxicants namely polychlorinated biphenyls (PCBs) is correlated with multiple health disorders including liver and cardiovascular diseases. The liver is important for both xenobiotic and endobiotic metabolism. However, the responses of an injured liver to subsequent environmental insults has not been investigated. The current study aims to evaluate the role of a compromised liver in PCB-induced toxicity and define the implications on overall body homeostasis. Male C57Bl/6 mice were fed either an amino acid control diet (CD) or a methionine-choline deficient diet (MCD) during the 12-week study. Mice were subsequently exposed to either PCB126 (4.9mg/kg) or the PCB mixture, Arcolor1260 (20mg/kg) and analyzed for inflammatory, calorimetry and metabolic parameters. Consistent with the literature, MCD diet-fed mice demonstrated steatosis, indicative of a compromised liver. Mice fed the MCD-diet and subsequently exposed to PCB126 showed observable wasting syndrome leading to mortality. PCB126 and Aroclor1260 exposure worsened hepatic fibrosis exhibited by the MCD groups. Interestingly, PCB126 but not Aroclor1260 induced steatosis and inflammation in CD-fed mice. Mice with liver injury and subsequently exposed to PCBs also manifested metabolic disturbances due to alterations in hepatic gene expression. Furthermore, PCB exposure in MCD-fed mice led to extra-hepatic toxicity such as upregulated circulating inflammatory biomarkers, implicating endothelial cell dysfunction. Taken together, these results indicate that environmental pollution can exacerbate toxicity caused by diet-induced liver injury which may be partially due to dysfunctional energy homeostasis. This is relevant to PCB-exposed human cohorts who suffer from alcohol or diet-induced fatty liver diseases.
Topics: Adipokines; Animals; Aroclors; Biomarkers; Blood Glucose; Cardiovascular Diseases; Choline; Diet; Disease Models, Animal; Energy Metabolism; Fatty Liver; Gene Expression; Homeostasis; Inflammation; Liver; Liver Cirrhosis; Male; Methionine; Mice, Inbred C57BL; Polychlorinated Biphenyls
PubMed: 28163111
DOI: 10.1016/j.tox.2017.02.001 -
PloS One 2022Iron and steel industries are the major contributors to persistent organic pollutants (POPs). The microbial community present at such sites has the potential to...
Metagenomic analysis for taxonomic and functional potential of Polyaromatic hydrocarbons (PAHs) and Polychlorinated biphenyl (PCB) degrading bacterial communities in steel industrial soil.
Iron and steel industries are the major contributors to persistent organic pollutants (POPs). The microbial community present at such sites has the potential to remediate these contaminants. The present study highlights the metabolic potential of the resident bacterial community of PAHs and PCB contaminated soil nearby Bhilai steel plant, Chhattisgarh (India). The GC-MS/MS analysis of soil samples MGB-2 (sludge) and MGB-3 (dry soil) resulted in identification of different classes of POPs including PAHs {benzo[a]anthracene (nd; 17.69%), fluorene (15.89%, nd), pyrene (nd; 18.7%), benzo(b)fluoranthene (3.03%, nd), benzo(k)fluoranthene (11.29%; nd), perylene (5.23%; nd)} and PCBs (PCB-15, PCB-95, and PCB-136). Whole-genome metagenomic analysis by Oxford Nanopore GridION Technology revealed predominance of domain bacteria (97.4%; 97.5%) followed by eukaryote (1.4%; 1.5%), archaea (1.2%; 0.9%) and virus (0.02%; 0.04%) in MGB-2 and MGB-3 respectively. Proteobacteria (44.3%; 50.0%) to be the prominent phylum followed by Actinobacteria (22.1%; 19.5%) in MBG-2 and MBG-3, respectively. However, Eukaryota microbial communities showed a predominance of phylum Ascomycota (20.5%; 23.6%), Streptophyta (18.5%, 17.0%) and unclassified (derived from Eukaryota) (12.1%; 12.2%) in MGB-2 and MGB-3. The sample MGB-3 was richer in macronutrients (C, N, P), supporting high microbial diversity than MGB-2. The presence of reads for biphenyl degradation, dioxin degradation, PAH degradation pathways can be further correlated with the presence of PCB and PAH as detected in the MGB-2 and MGB-3 samples. Further, taxonomic vis-à-vis functional analysis identified Burkholderia, Bradyrhizobium, Mycobacterium, and Rhodopseudomonas as the keystone degrader of PAH and PCB. Overall, our results revealed the importance of metagenomic and physicochemical analysis of the contaminated site, which improves the understanding of metabolic potential and adaptation of bacteria growing under POP contaminated environments.
Topics: Bacteria; Polychlorinated Biphenyls; Soil; Soil Pollutants; Steel; Tandem Mass Spectrometry
PubMed: 35486615
DOI: 10.1371/journal.pone.0266808 -
The Science of the Total Environment Dec 2022We report individual polychlorinated biphenyl congeners and the sum of all congeners (ΣPCB) in residential soils of East Chicago, Indiana. ΣPCB in soils ranged from 20...
We report individual polychlorinated biphenyl congeners and the sum of all congeners (ΣPCB) in residential soils of East Chicago, Indiana. ΣPCB in soils ranged from 20 to 1700 ng/g dry weight (DW), with a geometric mean of 120 ng/g DW. These values are significantly higher than other locations, but similar or lower to locations nearby well-known PCB contamination sites. No PCB spatial distribution pattern was observed. PCB concentrations increase with total organic carbon in the soils and proximity to Indiana Harbor and Ship Canal (IHSC), where sediments are contaminated with PCBs. Most samples are similar in their PCB distribution and Aroclor 1254 yielded the highest similarity to all the samples. A fifth of the samples highly resemble other PCB profiles such as EPA background and Cedar Rapids Iowa soils, and volatilization from Lake Michigan, whereas volatilization from IHSC could not explain the PCBs found in soils. IHSC was expected to be the main source of PCBs in the nearby soils. It is possible that soils are impacted by variety of known and unknown sources, including volatilization from Lake Michigan, resulting in a regional PCB signal. Although PCB concentrations are higher than other locations, samples were below the current US EPA non-cancer residential soil level remediation goal for dioxin TEQ.
Topics: Carbon; Chicago; Chlorodiphenyl (54% Chlorine); Dioxins; Environmental Monitoring; Lakes; Michigan; Polychlorinated Biphenyls; Soil
PubMed: 35931157
DOI: 10.1016/j.scitotenv.2022.157705 -
The disposition of polychlorinated biphenyls (PCBs) differs between germ-free and conventional mice.Environmental Toxicology and... May 2022The disposition of toxicants, such as polychlorinated biphenyls (PCBs), in germ-free (GF) vs. conventional (CV) mice has received little attention to date. Here, we...
The disposition of toxicants, such as polychlorinated biphenyls (PCBs), in germ-free (GF) vs. conventional (CV) mice has received little attention to date. Here, we investigate PCB levels in three-month-old female CV and GF mice exposed orally daily for 3 days to 0, 6, or 30 mg/kg body weight of the Fox River Mixture (FRM), an environmental PCB mixture. We euthanized animals 24 h after the final dose. PCB profiles in tissues differed from the FRM profile but were similar in tissues across all 4 PCB exposure groups. PCB levels in CV but not GF mice followed the difference in PCB dose. Importantly, PCB levels were higher in CV than GF mice exposed to the same dose. Hepatic cytochrome P450 enzyme or lipid levels did not explain these trends in PCB tissue levels. Thus, toxicity studies with CV and GF animals need to assess the toxicokinetics of the toxicant investigated. CAPSULE: PCB levels are typically higher in conventional than germ-free mice exposed to the same dose of PCBs.
Topics: Animals; Female; Liver; Mice; Polychlorinated Biphenyls
PubMed: 35331926
DOI: 10.1016/j.etap.2022.103854 -
Microbiology Spectrum Dec 2021Polychlorinated biphenyls (PCBs) are recalcitrant organohalide pollutants, consisting of 209 congeners. PCB cleanup in natural landscapes is expected to be achieved by...
Polychlorinated biphenyls (PCBs) are recalcitrant organohalide pollutants, consisting of 209 congeners. PCB cleanup in natural landscapes is expected to be achieved by the metabolic activity of microorganisms, but aerobic PCB-degrading bacteria that inhabit sites polluted by PCBs cannot degrade all PCB congeners due to the specificity of their enzymes. In this study, we investigated the degradability of PCBs when a genetically modified PCB-degrading bacterium was compounded with wild-type PCB-degrading bacteria. We used two bacterial strains, Comamonas testosteroni YAZ2 isolated from a PCB-uncontaminated natural landscape and Escherichia coli BL21(DE3) transformed with a biphenyl dioxygenase (BphA) gene from a well-known PCB degrader, Burkholderia xenovorans LB400. The enzymatic specificities of BphA were 2,3-dioxygenation in the YAZ2 and 2,3- and 3,4-dioxygenations in the recombinant E. coli. For the PCB-degrading experiment, a dedicated bioreactor capable of generating oxygen microbubbles was prototyped and used. The combined cells of the recombinant and the wild-type strains with an appropriate composite ratio degraded 40 mg/L of Kaneclor KC-300 to 0.3 ± 0.1 mg/L within 24 h. All of the health-toxic coplanar PCB congeners in KC-300 were degraded. This study suggested that the augmentation of an engineered bacterial strain could improve the cleanup of PCB water pollution. It also revealed the importance of the ratio of the strains with different PCB-degrading profiles to efficient degradation and that the application of oxygen microbubbles could rapidly accelerate the cleanup. PCB cleanup technique in a natural environment relies on the use of enzymes from microorganisms, primarily biphenyl dioxygenase and dehalogenase. Herein, we focused on biphenyl dioxygenase and created a recombinant PCB-degrading E. coli strain. Despite the development of environments for the field use of transgenic microbial strains around the world, verification of the applicability of transgenic microbial strains for PCB cleanup in the field has not yet been reported. We tentatively verified the extent to which degradability could be obtained by an augmentation model of a transgenic strain, the enzyme expression of which is easily regulated in rivers and lakes with PCB pollution. Our experiments used a dedicated bioreactor to model the natural landscape and produced results superior to those of bioremediation or biostimulation methods. The application of micro-nano bubbles, which has recently been discussed, to the cleanup of environmental pollution was also found to be useful in this study.
Topics: Biodegradation, Environmental; Escherichia coli; Metabolic Engineering; Polychlorinated Biphenyls; Water Pollutants, Chemical; Water Pollution
PubMed: 34937186
DOI: 10.1128/spectrum.01926-21 -
Toxicology and Applied Pharmacology Jan 2019The endocrine disrupting chemicals, polychlorinated biphenyls (PCBs), have been associated with nonalcoholic steatohepatitis (NASH) and diabetes. However, an integrative...
The endocrine disrupting chemicals, polychlorinated biphenyls (PCBs), have been associated with nonalcoholic steatohepatitis (NASH) and diabetes. However, an integrative analysis of the effects of PCBs on the liver and pancreas has never been performed for the two major PCB subtypes, dioxin-like (DL) and nondioxin-like (NDL), and a mixture of NDL/DL PCBs. Therefore, male C57BL/6 J mice fed a control synthetic diet were treated with either a NDL PCB mixture, Aroclor 1260 (20 mg/kg); a single DL PCB congener, PCB 126 (20 μg/kg); a NDL/DL mixture, Aroclor 1260 plus PCB 126; or vehicle control for 2 weeks. PCB126 had the greatest impact on hepatic lipid metabolism. It caused steatosis due to increased hepatic lipid import with associated hypolipidemia. However, all PCB exposures impacted expression of hepatic lipid metabolism genes in different manners. The 'NASH gene', Pnpla3, was elevated by Aroclor 1260, but decreased by all other exposures. The expression of hepatokines implicated in metabolic syndrome (Fgf21, Igf1, and betatrophin) were differentially regulated. The NDL/DL PCB mixture had the greatest effects on pancreatic histology, including acinar cell atrophy, mild steatosis, and fibrosis without ductal changes or immune cell infiltration. It decreased expression of insulin and altered the expression of genes regulating islet identity. None of these exposures was associated with altered HOMA-IR or HOMA-B. In summary, PCB exposures differentially regulated liver and pancreas structure and function. Novel mechanisms for PCB-induced endocrine/metabolic disruption included altered hepatokines and Pnpla3 as well as 'PCB pancreatopathy' that was associated with altered expression of pancreatic islet identity factors. More research is required to understand fully these findings in the context of human NASH and diabetes.
Topics: Animals; Aroclors; Diabetes Mellitus; Disease Models, Animal; Endocrine Disruptors; Fibrosis; Humans; Lipid Metabolism; Liver; Male; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Pancreas; Phospholipases A2, Calcium-Independent; Polychlorinated Biphenyls
PubMed: 30312631
DOI: 10.1016/j.taap.2018.10.011