HAEMOLYMPH PROTEINS AND YOLK FORMATION IN COCKROACH, LEUCOPHAEA MADERAE

The soluble proteins of the ovary of Leucophaea were separated with disk electrophoresis on acrylamide gels at different times during vitellogenesis, and the concentrations of different fractions were compared to the corresponding fractions of haemolymph proteins. Most of the haemolymph proteins can also be detected in the ovaries. This together with structural evidence derived from electron microscope studies makes it highly probable that haemolymph proteins are taken up as whole molecules into the oöcytes during yolk formation. However, this uptake is a selective process: not all proteins are absorbed and those which are absorbed are taken up at different rates which do not correspond to their concentrations in the haemolymph. Furthermore there are more soluble proteins in the ovaries than in the haemolymph and their number increases during oöcyte maturation from 15 to 21. Therefore some proteins are synthesized in the oöcytes or in the follicle cells or the proteins which are taken up are modified in different ways. Also there is evidence for some proteins becoming insoluble in the course of yolk formation. A typical 'female protein' which is present only in the haemolymph of females during oöcyte maturation seems to be incorporated at highest rates into the oöcytes, where at one time it makes up the highest proportion of all soluble proteins. © 1969.