Meeting Abstract

92.1  Wednesday, Jan. 7  Competition of tyrosine with alkylphenols during shell hardening in new cuticle of lobsters CHEN, Ming*; JOCOBS, Molly/W; LAUFER, Hans; Univ. of Connecticut laufer@uconn.edu

Alkylphenols, anthroprogenic estrogenic endocrine distrutors, were found in naturally occurring lobsters (Homarus americanus) with or without epizootic shell disease. We hypothesize that alkylphenols interfere in shell hardening during molting, weakening cuticular structure, and making the cuticle susceptible to microbial invasion. Tyrosine, an alkylphenolic amino acid, is a starting component of normal sclerotization crosslinking proteins. In this study, we used an in vitro cuticle bioassay to investigate the effects of one of these compounds, 2,4-bis-(dimethylbenzyl) phenol, on tyrosine incorporation during hardening of new cuticle during lobster molting. We measured incorporation of ¹⁴C-tyrosine during shell hardening in the presence and absence of the alkylphenol, and found that it inhibited tyrosine incorporation by 59.43.7%. This process was phenoloxidase dependent, since it was inhibited with phenylthiourea by 79.29.4%. The cold tyrosine inhibited ¹⁴C-tyrosine incorporation by 56.37.4%. We also found that alkylphenols inhibited hypodermal cells from transporting tyrosine by 25.68.5% during the shell hardening process. We tested shell hardening following molting in vivo by measuring the force required to indent the shells. When lobsters were injected with alkylphenol, their new shell required a 5 lb. force by an average of 12 days. Control lobsters new shells could resist a 5 lb. force by 5 – 8 days. Our results suggest that alkylphenols appear to delay shell hardening during the molting process. The weakened shell may be a possible contributor to lobster shell disease.