Toxic effects of microcystins in the hepatopancreas of the estuarine crab Chasmagnathus granulatus (Decapoda, Grapsidae)

A study on the effects of food quantity and quality on glutathione S-transferase (GST) activity and growth rate parameters of Daphnia carinata varying in age

“…Daphnids usually have a slow growth rate and a low reproductive capacity as a defence mechanism if food conditions deteriorate (Threlkeld 1979;Lampert 1986;Lynch 1989;DeMott 1999;Reinikainen et al 1999;Repka et al 1999). The induction of GST activity on exposure to CDNB, PNNB, EA, and Trans in D. carinata is considered to be an effective defence mechanism (Wiegand et al 1999;Best et al 2002;Pinho et al 2003;Gustafsson Pflugmacher et al 2005), especially in treatment involving low food quantity (such as 1000 cells/ml S. obliquus concentration in the present study); GST towards several substrates in adults is much higher than juveniles. From the work of Vijverberg (1976), it seems that if daphnids are fed enough edible food, large numbers of small offspring are produced and these offspring have a lower tolerance to adverse effects of insufficient food and toxins.…”

“…Microcystin concentrations in animal tissue decreased because of its high GST activity, therefore, its high capacity to biotransform MCs (Pflugmacher et al 1998(Pflugmacher et al , 2005. Previous studies reported increase in GST activity in many animals exposed to microcystins for a short time (Wiegand et al 1999;Best et al 2002;Pinho et al 2003), suggesting their substantial roles in the toxicity reduction of some toxins, as indicated by increase of LD 50 s and decline of mortality in various insects (Hayaoka and Dauterman 1982;Vontas et al 2001). Chen et al (2005) reported that GST activity (to CDNB) of Daphnia magna decreased when it was exposed to microcystins for several weeks.…”

Sequential ultrastructural and biochemical changes induced in vivo by the hepatotoxic microcystins in liver of the phytoplanktivorous silver carp Hypophthalmichthys molitrix

“…The formation of microcystin-GSH conjugate mediated by GST has been confirmed as the first step in the detoxification of MCs in aquatic plants, crustaceans mollusks and fish (Pflugmacher et al, 1998). Pinho et al (2003) found a higher GST activity in the hepatopancreas of C. granulatus 7 days after MCs exposure, which suggests a higher conjugation rate of MCs with GSH. In our experiment, the significant increase of GST activity in the liver of silver carp was observed at 24 and 48 h post-injection, respectively.…”

“…The GST is a ubiquitous Phase II enzyme responsible for the detoxification of xenobiotics, toxins and endogenous substrates including the toxic products of tissue damage (Storey, 1996). An increase in GST activity was found in the hepatopancreas of Chasmagnathus granulatus after MCs exposure representing a greater detoxification capacity through conjugation of MCs with glutathione (GSH) (Pinho et al, 2003). The depletion of the hepatic GSH after exposure to MC-LR was observed in the studies with goldfish (Xu et al, 1998) and common carp (Li et al, 2003).…”

Antioxidant enzyme activities of Microcystis aeruginosa in response to nonylphenols and degradation of nonylphenols by M. aeruginosa

“…One of its more important functions is to exclude ROS before these reactive molecules can initiate their chain reaction-damaging effects on macromolecules (Pinho et al, 2003). It also plays an important role in the detoxification and clearance of toxins (Pflugmacher et al, 1998).…”