blog of sinaling pathways t at ecdysis and peaked in early pre moult. This expression profile was also observed for transcripts associated with mitochon drial energy metabolism such as ATP synthase, cytochrome oxidase and NADH dehydrogenase. Metal lothionein is a ubiquitous Inhibitors,Modulators,Libraries heavy metal binding protein, involved in copper homeostasis and detoxification. Studies in C. sapidus have demonstrated the presence of metallothionein in pre moult crabs, suggesting that metallothionein is required for the regulation of biologi cally available copper ions necessary for the oxygen bind ing properties of hemocyanin. Crustacean metallothionein has Inhibitors,Modulators,Libraries also been implicated in the regula tion of energy metabolism by affecting mitochondrial respiration. Investigations on H.

americanus demon strated that metallothionein is present in the intermem brane space of hepatopancreatic mitochondria and is able to regulate the oxygen consumption of mitochondria in a zinc dependant manner. The synchronous expres sion profile of metallothionein and several genes involved in mitochondrial respiration, observed here in Cluster A, support the hypothesis of a regulatory Inhibitors,Modulators,Libraries role for metal lothionein in energy production. Metallothionein was also found to exert a protective effect against the highly reactive oxygen species generated by oxygen metabolism in the presence of zinc. Free zinc in quantities equivalent to those tested when bound by metallothio nein increased the levels of reactive oxygen species by four fold.

Crustaceans have been found to store consider able levels of metals such as calcium, copper and zinc in the hepatopancreas during the pre moult stage of the moult cycle, moreover induction of metallothionein levels in the hepatopancreas occurs at high zinc concen trations. The accumulation of zinc in the hepatopan creas during pre moult, together Inhibitors,Modulators,Libraries with the role of zinc in inducing oxidative stress, accentuates the requirement for protective measures against free radical formation in this moult cycle stage. The peak of metallothionein expression in pre moult lends further support to the implied role of metallothionein in metal Drug_discovery detoxification and energy metabolism. Phenoloxidase activity PO activators such as the serine proteases trypsin, chy motrypsin, and trypsinogen, in addition to antimicrobial and clotting proteins, made up 5% of the total distribu tion of sequenced cDNAs.

Trypsin and chy motrypsin both displayed moult cycle related differential expression in that they were highly up regulated in intermoult and pre moult when compared to selleck chemical ecdysis and post moult. Trypsin is one of the major digestive proteases secreted by the hepatopan creas, chymotrypsin also, is a serine protease recently identified in the digestive systems of crusta ceans. Studies on Penaeus vannamei revealed that mRNA expression of trypsin is at a maximum during early premoult, then declines sharply in late premoult. The specific activity of trypsin also followed this pattern, suggesting the regulation of trypsin biosynthesis is,