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 divi ded into two major phases, namely primary- and secondary-vitellogenesis. Tw o anatomically distinctive types of primary-vitellogenic ovary are present: one contains uniform milky white oocytes (in the chromatin, chromatin-nucl eolus, early-perinuclear and late-perinuclear stages), while the other cont ains two diversely colored oocyte populations, the smallest oocytes being u niform milky white and the largest being yellow to orange (i.e., at the lip id 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 develop s 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 oocyt es. Polypeptides of relatively higher molecular masses (>100 kDa) were dete cted both in the secondary-vitellogenic ovary (composed mainly of yolk-stag e oocytes) and in newly laid eggs. During secondary vitellogenesis, the hig h-density lipoprotein (HDL) fraction of the hemolymph contains four seconda ry vitellogenic-specific polypeptides (208, 196, 177 and 80 kDa) that are n ot present in the hemolymph of the primary vitellogenic female. In this stu dy we have elucidated the relationship between the progress of gonad matura tion, oocyte development and the sequence of appearance of specific polypep tides in the ovary and the hemolymph of C. quadricarinatus.