Attachment of Pastezlria penetrans spores cuticles of root-bot nematodes to the

Several experiments were carried out to elucidate the nature of the process of attachment of Pasteuria penetrans spores to second-stage juveniles of Meloidogyne javanica. Sonication of spores for 5-30 mn disrupted the sporangial Wall and significantly increased the rate at which spores attached to nematodes. Spores attached equally well to living and dead nematodes. Some spores attached to nematodes after either spores or nematodes were heated at 100 ” for 30 mn, but spores heated at 100 ’ for 15, 30 or 60 mn attached in significantly fewer numbers than unheated spores. Spores also adheredto free living and parasitic second-stage juveniles but not to males and females, suggesting that recognition sites for spore adhesion were altered during moulting. The sites of spore adhesion were randomly distributed on the surface of the cuticle. Preliminary studies failed to implicate lectins in the adhesion process because a range of sugars, lectins and other compounds did not affect attachment. Sialic acid reduced the number of spores attached to nematodes in two experiments but other evidence suggested it was unlikely to be involved in the mechanism of attachment. Observation at high resolution under the TEM of sections cut through the spore on the surface of the cuticle showed that the glycocalyx broke down and the parasporal fibres from the lower half of the spore became inserted and entwined within the epicuticle. RESUME La fixation des spores de Pasteuria penetrans sur la cuticule du neinutode des racines noueuses Plusieurs expériences ont été effectuées pour élucider le procédé de fixation des spores de Pasteuria penetrans sur les juvéniles de secon