Applied Biology and Biochemistry Conference Papers

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Browsing Applied Biology and Biochemistry Conference Papers by Subject "Antioxidant Enzymes"

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    Metal Levels and Antioxidant Enzyme Activities in Freshwater Snails Exposed to Sediments From Polluted and Pristine Dams in Zimbabwe
    (2013-03-12) Naik, Yogeshkumar S.; Nyathi, C.B.; Siwela, Andrew H.
    The aim of this study was to determine the metal and antioxidant enzyme activities (AGE's) in the freshwater snail Lymnaea natalensis, exposed to sediments form a polluted (Umguza) and pristine (Wright) dams around Bulawayo City, Zimbabwe with a view to developing a biomarker of freshwater pollution. Adult lab reared snails (10-15 mm) were exposed for 4 weeks to water and sediment cofiected from 4 different sites of Umguza Dam (a sink of domestic and industrial effluent) and Wright Dam (privately owned -and considered to be relatively pristine). Antioxidant. enzymes, heavy metals and malondia1dehyde (MDA) analyses were performed using the S-9 fraction of whole snail soft tissue. Catalase and glutathione peroxidase activities were significantly elevated in snails exposed to Umguza Dam water and sediment (Student t-test, p < 0.01 and p < 0.001) when compared to snails exposed to Wright Dam. DT- diaphorase activity was significantly reduced in snails exposed to Umguza Dam water and sediment (p < 0.001) when compared to snails exposed to Wright Dam water and sediment. Snails exposed to Umguza Dam water and sediment bad a higher total metal load compared to those exposed to Wright Dam elements and the MDA levels were correspondingly elevated in snails exposed to polluted water and sediment (p < 0.01). The higher MDA levels and altered AGE activities suggest that the snails exposed to Umguza Dam elements are under higher oxidative stress.
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    Species and Sex Related Differences in Antioxidant Enzymes in Fish Collected From Umguza and Auchmacoy Wright Dams, Bulawayo, Zimbabwe.
    (2013-03-12) Nyathi, C.B.; Siwela, Andrew H.; Naik, Yogeshkumar S.
    Agricultural and industrial activity results in the pollution of our environment by pesticides and metals usually causing deleterious effects on both humans and other animals in the environment. We are interested in the effects of pesticides and metals on non-human targets, such as fish, in the environment. Literature reports suggest that there are species and sex differences amongst fish in the metabolism of foreign compounds (xenobiotics) on the detoxifying enzymes of aquatic organisms. The aim of this study was to assess whether there are any species and sex differences in antioxidant enzyme activities of local fish. Catfish (Clarius gariepinus) and bream (Oreochromis mossambicus) collected from two dams, one polluted (Umguza) and one pristine (Auchmacoy Wright) in the Bulawayo area. Gills, liver and kidneys from captured (gill netted) fish were excised, homogenized and centrifuged to obtain S-9 fractions. The S-9 fraction was used to assay for activities of the antioxidant enzymes, catalase, glutathione peroxidase and DT- diaphorase. Significant sex-related differences in the activity of catalase in liver and gill but not in kidney of catfish collected from Umguza Dam were noted (Student t test, P< 0.05). No sex-related differences in catalase activity were observed in bream tissues collected from Umguza Dam. Catalase activity in female bream collected from Umguza Dam was/significantly higher when compared to female catfish catalase from the same dam. Glutathione peroxidase activity in catfish collected from Umguza Dam were Seen to be sex dependent in gill and liver but not in kidney (Student t test, P < 0.05) whilst species differences were noted only in liver, with higher activities in catfish. Umguza bream showed significant sex differences in glutathione peroxidase activity onfy in the gills. DT- diaphorase activity in catfish collected from Umguza Dam was shown to be sex dependent in gill and kidney but not in liver. In Umguza bream, DT-diaphorase activity was seen to be sex dependent only in gills. Species differences in DT-diaphorase activity were only seen when male catfish and male bream were compared. DT-diaphorase activity was shown to be significantly higher in male catfish compared to male bream but there were no differences in activity when female catfish were compared to female bream in all the tissues. For fish collected from Auchmacoy Wright Dam, significant differences in bream catalase activity was seen in all the three tissues studied. Species difference in catalase activity were noted in liver and gill but not in kidney. Significant sex differences in the activity of glutathione peroxidase were noted only in the kidneys of the bream. Species differences in glutathione peroxidase activity were noted only in the gills of female fish. No significant diffe.rences in DT-diaphorase activity either by sex or species were noted in all the tissues of fish collected from Auchmacoy Wright Dam. Our data indicates that enzyme activity is species, sex and tissue dependent in fish and that enzyme activity is also affected by the presence of pollutants.