IN SITU STUDIES ON THE SEASONAL VARIATION OF GUT CYANOPHYTA CONTENTS AND LIVER GST EXPRESSION OF SILVER CARP (HYPOPHTHALMICHTHYS MOLITRIX) AND GRASS CARP (CTENOPHARYNGODONIDELLA)

摘要

The information on the relationship of fish gut Cyano-phyta contents and liver glutathione S-transferase (GST) expression is important to understand the detoxification of microcystins (MCs) in liver via conjugation to glutathione (GSH) by GST. In this study, the water and gut contents of phytoplanktivorous sliver carp (Hypophthalmichthys mo-litrix) and herbivorous grass carp (Ctenopharyngodon idella) were studied in tropical Xiangang Reservoir between Oct. 2007 and Jul. 2008. Meanwhile, the varified mRNA abundance of 5 liver GST genes was determined by quantitative real-time PCR (Q-PCR). The results showed that the relative liver GST mRNA abundance had a positive correlation with the Cyanophyta quantity in the gut contents of sliver carp as well as in the water contents which grass carp might contact with. In the present study, we also found that the expression of GSTM and GSTA dramatically decreased in the blooms-occurring month which suggested that GSTM and GSTA could be developed as the biomarkers of silver carp and grass carp, respectively, for monitoring cyanobacterial blooms in reservoirs, especially those for providing drinking water.