Effects of Monoclonal Antibodies, Cationized Ferritin, and Other Organic Molecules on Adhesion of Pasteuria penetrans Endospores to Meloidogyne incognita

Abstract

The incidence of adhesion of Pasteuria penetrans endospores to Meloidogyne incognita second-stage juveniles (J2) was studied after pretreatment of the latter with monoclonal antibodies (MAb), cationized ferritin, and other organic molecules in replicated trials. Monoclonal antibodies developed to a cuticular epitope of M. incognita second-stage juveniles gave significant reductions in attachment of P. penetrans endospores to treated nematodes. MAb bound to the entire length of J2 except for the area of the lateral field, where binding was restricted to the incisures. Since reductions in attachment with MAb treatment were modest, it is uncertain if these results implicated a specific surface protein as a factor that interacted in binding of the endospore to the nematode cuticle. Endospore attachment was decreased following treatment of the nematode with the detergents sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB). Endospore attachment to live nematodes was significantly greater than attachment to dead nematodes. Attachment rates of three P. penetrans isolates to M. incognita race 3 varied between isolates. The effects of neuraminidase, pronase, pepsin, trypsin, lipase, and Na periodate on endospore attachment were inconsistent. The cationic dye alcian blue, which binds sulfate and carboxyl groups on acidic glycans, had no consistent effect on endospore attachment. The incidence of endospore attachment was significantly lower but modest, at best, for nematodes that were treated with cationized ferritin alone or cationized ferritin following monoclonal antibody. The lack of consistency or extreme reduction in most experiments suggests that attachment of P. penetrans spores to M. incognita is not specified by only one physico-chemical factor, but may involve a combination of at least two physico-chemical factors (including surface charge and movement of the J2). This points to a need for analysis of combined or factorial treatment effects. Key words: adhesion, bacterium, binding site, biological control, cationized ferritin, cuticle, Meloidogyne incognita, monoclonal antibody, nematode, Pasteuria penetrans, root-knot nematode, surface charge, surface coat.