Assessment of pollution in sewage ponds using biomarker responses in wild African sharptooth catfish (Clarias gariepinus) in Tanzania.

The interactive effects of mixed pollutants in sewage wastewater on biomarker responses were investigated using wild male African sharptooth catfish (Clarias gariepinus) in Morogoro, Tanzania. A total of 58 fish were used, of which 21 were from Mindu dam (reference site) and 22, 9 and 10 from Mafisa, Mazimbu and Mzumbe sewage ponds, respectively. Liver somatic index (LSI) and gonadosomatic index (GSI) were significantly greater (two- to threefold) and (five- to sixfold), respectively, in fish from all sewage ponds.

Vitellogenin in African sharptooth catfish (Clarias gariepinus): purification, characterization, and ELISA development.

Vitellogenin (Vtg) induction in African sharptooth catfish (Clarias gariepinus) was assessed in order to develop a method for monitoring estrogenic pollution in African freshwater systems. Clarias gariepinus Vtg (Cg-Vtg) was purified from serum obtained from 17alpha-ethynylestradiol (EE2)-exposed fish and polyclonal antibodies against Cg-Vtg were raised. An enzyme-linked immunosorbent assay (ELISA) was developed and the induction and kinetics of Vtg were assessed in male fish in three different exposure trials using both natural estrogen (17alpha-estradiol [E2]) and synthetic EE2.

Estrogenic effects of selected hydroxy polychlorinated biphenyl congeners in primary culture of Atlantic Salmon (Salmo salar) hepatocytes.

Many persistent organic pollutants are known to have endocrine-disrupting effects in several aquatic and terrestrial species. In this regard, hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) represent serious health and environmental concern because they are shown to act agonistic or antagonistic at hormone receptors (HRs) or to cause hormone-receptor-mediated responses. In the present study, salmon primary hepatocytes were used to study alterations in an estrogen signaling pathway resulting from exposure to four hydroxylated (4OH-CB 107, 4OH-CB146, 4OH-CB187, and 3OH-CB138) metabolites of PCB at different concentrations using quantitative real-time polymerase chain reaction.

Effects of hydroxy-polychlorinated biphenyl (OH-PCB) congeners on the xenobiotic biotransformation gene expression patterns in primary culture of Atlantic salmon (Salmo salar) hepatocytes.

Hydroxylated metabolites of PCBs [OH-PCBs] represent new health and environmental concern because they have been shown to have agonist or antagonist interactions with hormone receptors (HRs) or hormone-receptor mediated responses. The present study was designed to investigate the estrogenic potency based on anti-AhR signalling effect of three 4-OH substituted PCB congeners (#107, #146 and #187), one 3-OH substituted congener (#138), and the pharmaceutical synthetic estrogen, ethynylestradiol (EE2) in fish in vitro system using primary culture of Atlantic salmon hepatocytes. The effects were studied by quantifying changes in transcripts with gene-sequence primer pairs for a suite of gene responses (AhRalpha, ARNT, CYP1A1, CYP3A, UGT and GST) belonging to the xenobiotic biotransformation system.

Influence of 17alpha-ethynylestradiol on CYP1A, GST and biliary FACs responses in male African sharptooth catfish (Clarias gariepinus) exposed to waterborne Benzo[a]Pyrene.

Dose dependent effects of Benzo[a]pyrene (BaP) on cytochrome P4501A (CYP1A), glutathione-S-transferase (GST) and fluorescent aromatic compounds (FACs) metabolites biomarker responses were studied in African sharptooth catfish (Clarias gariepinus) following 24 h of waterborne exposures. Based on biomass of C. gariepinus in different tanks, BaP concentrations of 1.

Evaluation of the gill filament-based EROD assay in African sharptooth catfish (Clarias gariepinus) as a monitoring tool for waterborne PAH-type contaminants.

The ability of African sharptooth catfish (Clarias gariepinus) in inducing cytochrome P-450 class 1A (CYP1A) and glutathione S-transferase (GST) biomarkers was determined in liver and gill filaments after 4 days of waterborne exposure to the polycyclic aromatic hydrocarbon, benzo[a]pyrene (B[a]P). Male (n=6) and female (n=6) fish were exposed to B[a]P added to the water (30 microg/l) corresponding to 5 mg/kg total body weight. Five female and six male fish, exposed to acetone alone added to the water served as controls.

Thyroid hormone status in gray seal (Halichoerus grypus) pups from the Baltic Sea and the Atlantic Ocean in relation to organochlorine pollutants.

Marine apex predators, such as the gray seal (Halichoerus grypus), are exposed to high concentrations of organochlorine (OC) compounds via biomagnification in the food web. These lipophilic pollutants are transferred from the female to her offspring during lactation, and there is particular concern for endocrine disruption in the offspring. Herein we examined associations between the blubber concentrations of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and metabolites, chlordanes, hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB), and plasma concentrations of thyroid hormones (thyroxine [T4] and tri-iodothyronine [T3]) in free-ranging, newly weaned gray seal pups from the Baltic Sea and the Norwegian waters of the Atlantic Ocean.

Relationships between PCBs and thyroid hormones and retinol in female and male polar bears.

We studied the relationships between polychlorinated biphenyls (PCBs) and thyroid hormones (THs) and retinol within two groups of female polar bears (Ursus maritimus), females with cubs of the year (FWCOY) and females without cubs of the year (FWOCOY), and within a group of males. Concentrations of five of the six quantified PCB congeners, i.e.