The polypeptide components of the parasporal fibres of Pasteuria penetrans

A variety of treatments were tested for their ability to solubilize the parasporal fibres from Pasteuria penetrans, a parasite of some plant-parasitic nematodes. Selective solubilization of the parasporal fibres resulted from some of the extraction procedures tested. Subsequent acrylamide gel electrophoresis and Western blotting of the resolved polypeptides, using polyclonal sera against the spores. disclosed up to 15 distinct bands, ranging in size from 12 to 195 kDa. An N-terminal amino acid sequence was obtained from a 50 kDa polypeptide and an oligonucleotide primer deduced from it. A whole cell, fluorescent, primed in situ labelling (PRINS) technique was adapted to be applicable to spores of P. penetrans and P. ramosa, a parasite of water fleas. Positive responses were obtained using the parasporal fibre primer on spores of the former but not of the latter organism, implying that this 50 kDa polypeptide is produced by P. penetrans but not by P. ramosa.