Title

Responses of crustacea to hormones and shell disease

Date of Completion

January 2006

Keywords

Biology, Cell

Degree

Ph.D.

Abstract

The American lobster, Homarus americanus, is one of the most valuable species in commercial fisheries in the northeastern United States. In recent years, shell disease (SD) has been abundant in lobster populations in waters of southern New England, mainly eastern Long Island Sound, southern Massachusetts, and Rhode Island. ^ Molting, the process by which the exoskeleton is shed, is crucial for growth, regeneration and metamorphosis. Molting is induced by increased molting hormone, ecdysone, followed by a decrease prior to molting. ^ Shell-diseased lobsters tend to have a higher hemolymph ecdysone concentration than unaffected, healthy lobsters. Molting appears to be a lobsters defense to SD, even ovigerous (egg-bearing) female lobsters, which do not normally molt while carrying embryos, are found to molt more frequently to reduce injurious effects of SD. Molting can be induced experimentally by damaging the cuticle, suggesting that hemolymph ecdysone concentrations are elevated in wounded and SD animals. ^ We looked at the role of neuropeptide hormones from the eyestalks and methyl farnesoate (MF), a crustacean morphogenetic and reproduction hormone to characterize their role in controlling morphogenesis, metamorphosis and reproduction. Results showed that morphotypes in adult crayfish, Procambarus clarkii are controlled by MF. ^ The function of pure recombinant crustacean hyperglycemic hormone-B (CHH-B), originating from the eyestalk, was assessed. Our results showed that CHH-B is a multifunctional member of the CHH family with a minimum of five specific different endocrinological functions. ^