Meeting Abstract
Vitellogenin (Vg) is a protein synthesized and secreted from the hepatopancreas of crustaceans during ovarian maturation. Vg is taken up by ovaries during maturation and is modified to vitellin (Vn); it is the yolk-protein that will nourish the developing embryos. We purified Vg and Vn from the Northern spot shrimp (Pandalus platyceros) in order to develop a homologous ELISA with which to study the reproductive physiology of this species. P. platyceros is a commercially important protandric shrimp species and as such transforms from a functional male to a much larger adult female. Polyclonal antibodies were generated by a commercial vender against vitellogenin/vitellin that was previously purified from homogenates of ovaries obtained from mature adult female shrimp. Western blot analysis demonstrated that the immune serum specifically recocnized the Vn from P. platyceros ovarian homogenate and Vg from female but not male P. platyceros hemolymph. The standard curve was linear over a range of 75 to 1,800 ng/ml. The Vg ELISA will be used to assess the reproductive physiology of P. platyceros as they transform from males to females through a transitional phase. We hypothesize that the hormone that regulates male morphology and physiology (insulin-like androgenic hormone (IAG)) is no longer expressed in P. platyceros undergoing the male to female transition. The ELISA will be used in experiments in which the IAG gene is silenced by injection of males with double stranded RNA specific to IAG. Vg will be quantified in hemolymph samples from IAG silenced male and controls.
