Oocyte development and polypeptide dynamics during ovarian maturation in the red-claw crayfish Cherax quadricarinatus

Ovarian development in the red claw crayfish Cherax quadricarinatus is divided into two major phases, namely primary- and secondary-vitellogenesis. Two anatomically distinctive types of primary-vitellogenic ovary are present: one contains uniform milky white oocytes (in the chromatin, chromatin-nucleolus, early-perinuclear and late-perinuclear stages), while the other contains two diversely colored oocyte populations, the smallest oocytes being uniform milky white and the largest being yellow to orange (i.e., at the lipid stage). Secondary-vitellogenic ovaries are characterized by the presence of a synchronously growing large oocyte group together with oocytes of all the first four, primary-vitellogenic stages. The synchronous group develops from the yolk stage via the prematuration stage into the maturation stage. Polypeptides of relatively low molecular masses (65–95 kDa) are abundant in the primary-vitellogenic ovary containing chromatin to lipid-stage oocytes. Polypeptides of relatively higher molecular masses (<100kDa) were detected both in the secondary-vitellogenic ovary (composed mainly of yolk-stage oocytes) and in newly laid eggs. During secondary vitellogenesis, the high-density lipoprotein (HDL) fraction of the hemolymph contains four secondary vitellogenic-specific polypeptides (208, 196, 177 and 80 kDa) that are not present in the hemolymph of the primary vitellogenic female. In this study we have elucidated the relationship between the progress of gonad maturation, oocyte development and the sequence of appearance of specific polypeptides in the ovary and the hemolymph of C. quadricarinatus.