Expression profile of water-soluble proteinases during ontogenesis of Megachile rotundata: an electrophoretic investigation

Variations in proteinase activity pattern in larva, pupa and imago of the solitary bee Megachile rotundata are described. Extraction of insect homogenates under mild conditions was followed by the electrophoretic separation of the protein extract in polyacrylamide gels, precast with either gelatine or pollen protein extracts. In these conditions, twelve distinct proteinases were detectable in the pooled I-IV instar larvae, six in the pollen-eating V instar, two in the mature V instar, none in the diapausing V instar, none in the pupa, and two in the imago. Some of the detected proteinases were able to digest the protein mixture extracted from the pollen provisions. Some proteinases were insect specific since they were not detectable in pollen provisions extract. The enzymologic properties of the major proteolytic band suggest its serine-proteinase nature