Differentiation of lectin binding patterns in developing oocytes of the giant freshwater prawn, Macrobrachium rosenbergii

Abstract

Five different peroxidase-labeled lectins, Helix pomatia agglutinin (HPA), Concanavalin A agglutinin (Con A), Ricinus communis agglutinin (RCA-I), Wheat germ agglutinin (WGA) and Ulex europaeus agglutinin (UEA-I), were used to investigate alterations of the lectin binding patterns during oocyte development of the giant freshwater prawn, Macrobrachium rosenbergii. HPA, Con A and RCA-I binding sites were detected in the cytoplasm of developing oocytes; whereas HPA, WGA and UEA-I binding sites were localized on the oocyte surfaces. Although, HPA binding to the cytoplasm of developing oocytes could be detected at all stages of development, significant differentiation of the binding occurred at vitellogenic stage. Con A or RCA-I binding to the cytoplasm was first detected at early vitellogenic stage but the patterns of binding were altered at later stage. Moreover, HPA, Con A or RCA-I was reactive to different regions of the cytoplasm and produced different types of the reaction products. Formation of new surface components at vitellogenic stage was also implicated. The oocyte surfaces began to be reactive to HPA at early vitellogenic stage and were intensely reactive to HPA, WGA and UEA-I at late vitellogenic stage. Furthermore, affinity of HPA or RCA-I to the nucleolus was also detected at late vitellogenic stage.