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.
ABSTRACT
A new bacterial strain, strain CR-43T (T = type strain), which was isolated from tropical soil and was previously shown to have antinematodal and antibiotic properties, is described. The name Streptomyces costaricanus is proposed for this organism. The generic placement of strain CR-43T was based on its typical morphology, its production of LL-diaminopimelic acid, and its fatty acid composition. To clarify the taxonomic position of strain CR-43T, it was compared with the type strains of similar Streptomyces species. The results of a number of biochemical tests and a profile analysis of the hydrolyzable fatty acids indicated that CR-43T differs from previously described species. Strain CR-43 (= ATCC 55274 = NRRL B-16897) is the type strain of S. costaricanus sp. nov.
Subject(s)
Nematoda/physiology , Soil Microbiology , Streptomyces/classification , Animals , Pigmentation , Streptomyces/physiologyABSTRACT
Ten cultivars of watermelon were evaluated for their response to a Puerto Rican population of Meloidogyne incognita under greenhouse conditions in a 2-year study (1989 and 1990). Ten-day-old seedlings were planted in steam-sterilized soil in 15-cm-d plastic pots. The nematode inoculum consisted of 10,000 eggs and (or) second-stage juveniles (J2)/plant. The cultivars were Sugar Baby, Charleston Gray, Seedless, Prince Charles, Charleston 76, Jubilee, Florida Giant, Royal Charleston, Royal Sweet, and Royal Jubilee, with tomato cv. Rutgers included as a susceptible check. A completely randomized design with 10 replications was used. Fifty-five days after soil infestation, root-gall indices, numbers of nematode eggs per root system, and J2 per 250 cm(3) of soil were recorded. All cultivars were susceptible. Sugar Baby had the lowest root-gall index, egg and J2 numbers, and a reproductive factor (Rf) of 2.89. Rf differed (P
