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

Towards royal jelly proteome

The recent availability of the honey-bee Apis mellifera genome and trascriptome of both the female castes, has stimulated new efforts in investigating the protein composition of royal jelly (RJ), its role in caste differentiation and its quality and typicality by a proteomic approach. This study is aimed both to separate and identify proteins of royal jelly and to detect some of them in honey-bee pollen-bread by using two-dimensional gel electrophoresis, mass spectrometry and by de novo sequencing. All the identified proteins belonged to the Apis mellifera genome. Apalbumin 1 was also confirmed to be present in honey-bee pollen-bread where the presence of apalbumin 2 was also found. In addition several fragments of apalbumin 1 and apalbumin 3 were also found in RJ. These could be the result of protease activity other than that of serine-protease. This study is a contribution to the description of royal jelly proteome