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R. N. Binitha ¹, S. R. Soorya ¹, C. Aruna Devi ¹, Francis Sunny ¹

Affiliations
1 Department of Zoology, University College, Palayam, Trivandrum-695034, Kerala, IN

Abstract

This study investigated the impact of sewage effluents of the polluted river, Parvathyputhenar in Trivandrum city, Kerala, India, on the activities of osmoregulatory enzymes such as Na⁺/K⁺ and Ca²⁺ ATPases, the concentration of sodium and potassium ion content in the gill and on the chloride cells (CCs) and pavement cells (PCs) that regulate ions transport in the gill epithelium of a freshwater fish. The results indicate a significant (P<0.05) decrease in the activity of branchial Na⁺/K⁺ ATPase and Ca²⁺ ATPase in the fish exposed to sewage effluents for 7, 14 and 28 days and the fish caught from the polluted river. When the fish caught from the polluted river were kept in normal pond water in the laboratory for 30, 60 and 90 days, the enzyme's activities were gradually increased and almost restored to the control level. Scanning electron microscopic analysis of gill epithelium showed noticeable changes in the surface area morphology of CCs and PCs in the fish exposed to sewage effluents. Exposure to the sewage effluents drastically altered the size and characteristic "finger print" pattern of PCs and also reduced number of CCs in the gill epithelium. As the ATPases play an important role in maintenance of functional integrity of gill epithelium it is suggested that measurement of the activities of ATPases may be used as a biomarker of exposure to sewage effluents. This work is highly pertinent in the context of increased level and effect of endocrine disrupting chemicals present in the aquatic systems, which are increasing day by day.

Keywords

Sewage Effluents, Na⁺/K⁺ ATPase, Ca²⁺ ATPase, Chloride Cells, Pavement Cells.

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C. Aruna Devi ¹, R. N. Binitha ¹, S. R. Soorya ¹, B. V. Amrutha ¹, Francis Sunny ¹

Affiliations
1 Department of Zoology, University College, Thiruvananthapuram-695034, Kerala, IN

Abstract

Bisphenol-A (BPA), an industrial chemical used to manufacture polycarbonate plastic, is considered as a potent estrogenic endocrine disruptor. A majority of xenobiotics exert their toxic effect by causing generation of reactive oxygen species, leading to oxidative stress. Reports regarding oxidative stress responses to BPA in fish are scanty. From this viewpoint, in the present study, a freshwater fish, Anabas testudineus, was exposed to sub-lethal concentrations of BPA (2.5, 5.0,&7.5 mg/l), for different time periods (7, 15&30 days). Four major enzymes of the fish's antioxidant defense system viz., catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (Se-GPx), and glutathione-S-transferase (GST), and the non-enzymatic antioxidant glutathione (GSH) were chosen as biomarkers to examine the effects of BPA. The activities of SOD, GPx and GSH were elevated to significant levels, while CAT and GST activities were decreased significantly suggesting oxidative stress in BPAexposed fish. Reactive oxygen species are known to cause DNA fragmentation. Hence, DNA fragmentation assay was also done. The severity of DNA fragmentation in fish exposed to 7.5 mg/L BPA (30days) was remarkably increased (p<0.05 vs control) and this was revealed in gel electrophoresis analysis also. The results clearly show that BPA is a pollutant with oxidative potential, also with a potential for DNA fragmentation. The potential risks of this compound to nature and human populations are significant since the production of BPA related compounds is increasing dramatically each year.

Keywords

Endocrine Disruptor, Oxidative Stress, DNA Fragmentation, BPA, Antioxidants.

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Oommen V. Oommen ¹, Francis Sunny ²

Affiliations
1 Department of Zoology, University of Kerala, Kariavattom, Trivandrum 695 581, IN
2 Department of Zoology, University College, Trivandrum 695005, IN

Abstract

Steroid honnones regulate diverse biological functions by binding to intracellular receptors, which in turn alter the expression of genes. According to the common theory of steroid action, steroids modulate gene transcription by interacting with intracellular receptors, which act as ligand dependent transcription factors. Steroids regulate various genes either by positive or negative expression (1,2). Most of the steroid receptors are located in side the cell and hence the steroids need to get into the ceils and alter gene expression. The receptors for glucocorticoid, mineralocorticoid, progesterone and androgen are cytoplasmic and that of estrogen is nuclear (3). These receptors exist in inactive state in the cytoplasm or nucleus. The inactive state is maintained by their interaction with a group of receptor associated proteins called the chaperones and cochaperones (4,5). The mode of action of steroids requires intracellular localization of the steroid receptor and typically takes at least 30 to 60 min for the response. These cellular responses of steroids are known as the classical genomic action of steroids, which are characterized by a specific delay and sensitivity towards inhibitors of transcription and translation. The detailed description of steroid actions was the result of intensive long term research on steroid hormones.

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George Paul ¹, R. N. Binitha ², Francis Sunny ³

Affiliations
1 School of Ocean Sciences and Technology, Kerala University of Fisheries and Ocean Sciences, Kochi 682 506, IN
2 Department of Zoology, Mar Athanasius College, Kothamangalam 686 666, IN
3 Department of Zoology, University College, Thiruvananthapuram 695 034, IN

Abstract

Fish short-term reproductive assay (FSTRA) is a tier one assay for screening the endocrine disrupting property of a compound. This study analysed the end points like variations in Gonado-Somatic index (GSI), sperm quality and count, serum hormone levels (FSH, LH, estrogen and testosterone) to study the endocrine disrupting properties of butylated hydroxyanisole (BHA). A fresh water teleost, Anabas testudineus was used as animal model in this study. LC50 value of BHA was 250 mg/kg body weight in fish. Effects of four different doses of BHA were studied - 2, 5, 50 and 75 mg/kg body weight. BHA is found toxic at high doses of 250 mg/kg body weight and above. All the four doses of BHA caused significant impact on GSI, sperm count and quality. Serum hormone assay by ELISA showed significant variations in treated groups compared to control group.

Keywords

Anabas testudineus, Anisole, Endocrine Disruption.

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Subin Balachandran ¹, R. N. Binitha ², Francis Sunny ³

Affiliations
1 Department of Zoology, Sacred Heart College (Autonomous), Thevara - 682013, Kochi, Kerala, IN
2 Department of Zoology, Mar Athanasius College (Autonomous), Kothamangalam - 686666, Kerala, IN
3 Department of Zoology, Marian College of Arts and Science, Kazhakuttom, Trivandrum - 695582, Kerala, IN

Abstract

Scientists routinely use in-vivo animal experiments to study the reproductive and endocrine effects of various chemicals in humans. Rats are being used as the most suitable animal model for such investigations. Use of animal models to envisage the mode of action of a particular chemical in humans is questionable unless we can explain the binding similarities. In this study, an in-silico docking was employed to visualise if androgens and their agonists bind with androgen receptors of humans and rats in a similar pattern using BIOVIA Discovery Studio 2018. Amino acid residues involved in bond formation, nature of bonding, LibDock score and bond distances were calculated to compare the binding affinities. It was found that ASN 705, GLN 711, ARG 752 and THR 877 were the major amino acid residues in hydrogen bonding of selected ligands with both human and rat androgen receptors. Thus, the present study answers numerous questions that may arise while selecting rats as laboratory animal models to validate the androgenic effects of chemicals in humans.

Keywords

Androgen Agonist, Androgen Receptors, Biovia Discovery Studio, In-Silico Docking, Laboratory Animal Models

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