TOSTE, A.M.*; BAUER, D.K.; TSUKIMURA, B.: Reproductive properties of the Chinese mitten crab Eriocheir sinensis
The Chinese mitten crab, Eriocheir sinensis , invaded Central California’s waterways and expanded into the San Joaquin water system. Our focus is to study their reproductive capacity. We first investigated a portion of their reproductive cycle and found ovarian weights doubled from September (6.0 � 0.4g) to October (11.3 � 0.42g), then remained constant from October through February. The gonadosomatic index (GSI) doubled from 4 � 0.27% to 8 � 0.25% during the same time. We isolated and characterized the yolk protein, vitellin (Vn). Using FPLC, the molecular mass (MM) of Vn was 618 kDa. SDS-PAGE revealed Vn is composed of four subunits 129 � 1.8 kDa, 115 � 2.5 kDa, 105 � 1.5 kDa, and 95 � 1.7 kDa in MM. Digestion with PNGase-F reduced these subunits into three subunits, 119�3.6, 102�2.5, and 95�3.0 kDa indicating N-linked glycosylation of the two larger Vn subunits. NANase II and O-Glycosidase DS showed no quantifiable effect. Anti-Vn antisera was developed against native Vn. Western blots were used to demonstrate antisera specificity. ELISA’s, using a 1:14000 antisera dilution and having an effective range of 1- 300 ng, were developed to measure hemolymph concentrations of yolk proteins and to compare hemolymph concentrations with the GSI.