Phosphoprotein Patterns in Onchocerca Volvulus Developmental Stages

Abstract

Living females and microfilariae of Onchocerca volvulus incubated in culture medium containing [³²P]orthophosphate were observed to phosphorylate their proteins rapidly. Patterns of phosphoproteins in extracts from these labelled parasites were compared after two dimensional electrophoresis and autoradiography. Protein extracts from eggs, microfilariae and adult females of O. volvulus were phosphorylated in the presence of [γ - ³²P]ATP, magnesium acetate, and added cyclic AMP - dependent protein kinase or the endogenous protein kinase present in the extracts. Patterns of phosphoproteins were compared after separation by single and two - dimensional gel electrophoresis followed by autoradiography. Common phosphopeptide bands were observed when phosphorylated extracts from adult females, microfilariae and eggs were compared. However, extracts from eggs displayed unique phosphorylated polypeptides of M_r 30 000 and 34 000 that were absent from the extracts from microfilariae. Furthermore, two phosphorylated polypeptides of M_r 47 000 and 76 000 were detected in extracts from microfilariae but not from eggs. These results indicate that O. volvulus parasites may phosphorylate different proteins at different stages of their development.