| dc.description.abstract |
After serving as a neurotransmitter, acetylcholine is hydrolyzed by acetylcholinesterase (AChE). Inhibition of AChE is considered
to be a specific biomarker for exposure to organophosphate and carbamate insecticides. In this study, the AChE gene was isolated from
hybrid catfish brain by RT-PCR methods using degenerate primers. The amplified fragment of 966 nucleotides generated by PCR was
cloned, and sequence analysis showed 82% nucleotide identity with AChE of the Electrophorus electricus. Specific primers of the hybrid
catfish AChE gene were then synthesized and used in the examination of AChE gene expression in brain tissue of hybrid catfish exposed
to sublethal concentrations of chlorpyrifos (0.43, 4.3 and 43 µM) and carbaryl (1.19, 11.9 and 119 µM) for 24 hr. Real-time PCR was used
to compare with the amplified 28S rRNA gene. AChE gene expression was significantly elevated 12.4 times in catfish exposed to 43 µM
chlorpyrifos in comparison to the control group (p<0.05). Carbaryl did not produce any significant change. These results indicate that AChE
is more sensitive to administration of chlorpyrifos than carbaryl. The induction of the AChE gene indicates the possibility of using this gene
as biomarker for detecting effects of organophosphate insecticides in hybrid catfish. |
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