Detection of Biological Effects of Environmental Pollutants of the Kafue River on the Kafue Lechwe (KOBUS LECHE KAFUENESIS)by Characterization of Selected Biomarkers

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M’kandawire, Ethel
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A lot of research in ecotoxicology is currently focused on identifying and developing suitable biomarkers for use in assessing environmental pollution. Thus this study was aimed at assessing the potential of Cytochrome P450 1A1 (CYP 1A1), Cytochrome P450 3A (CYP 3A) and Metallothionein1 (MT 1) as biomarkers in the Kafue lechwe in response to pollutants in the Kafue river. Kafue lechwe liver samples from Lochnivar GMA (n=23) and Blue Lagoon GMA (n=15) were analyzed for the following biomarkers: CYP 1A1, CYP 3A and MT I. Complementary deoxyribonucleic acid (cDNA) was cloned and CYP lAl, CYP 3A and MT 1 partial nucleotide sequences were isolated from liver of Kafue lechwe. The deduced partial nucleotide sequence of lechwe CYP 1A1 revealed higher identities with that of sheep (98%) and cattle (97%). Lechwe CYP 3A revealed higher identities with that of CYP 3A24 of sheep (97%) and CYP 3A4 of cattle (95%). Lechwe MT 1 was closely related to MT of sheep (97%) and MT 1E of cattle (97%). In the phylogenetic analysis, the lechwe CYP 1A1 isoform was located beside sheep and cattle CYP 1A1. The lechwe CYP 3A isoform was located beside sheep CYP 3A24 and cattle CYP 3A4 and lechwe MT 1 isoform was clustered in the same group as that of sheep MT and cattle MT 1E. We then determined the mRNA expression levels of CYP 1A1, CYP 3A and MT 1 as biomarkers of pollution in liver of Kafue lechwe by relative quantitative real time reverse transcription polymerase chain reaction. The study showed that hepatic CYP 1A1, CYP 3A and MT 1 mRNA levels were expressed in all the lechwe samples from both Lochnivar and Blue Lagoon GMAs. However, there was a wide inter-individual variation in the gene expression of all the 3 genes in Kafue lechwe from both sites. Therefore a comparison of the gene expression levels between the two GMAs was determined by normalizing the relative quantities data for Blue Lagoon to one. Single factor ANOVA was employed for the statistical analysis. There was a 6 fold increase in CYP 1A1 mRNA expression in lechwe from Lochnivar GMA compared to lechwe from Blue Lagoon GMA and the difference was significant (P<0.05). There was no significant difference in CYP 3A and MT 1 mRNA expression levels between lechwe from Lochnivar GMA and lechwe from Blue Lagoon GMA (P>0.05). The study therefore demonstrates that hepatic CYP 1A1, CYP 3A and MT 1 mRNA expression levels in Kafue lechwe has the potential to be used as biomarkers of exposure and effect to pollution in the Kafue river.
Pollution--Enviromental aspects--Zambia , Pollution--Measurement--Zambia , Water Pollution--Zambia