Primary roots of soybean (Glycine max (L.), Merrill, cv. Harosoy 63) seedlings were inoculated with zoospores from either race 1 (incompatible, host resistant) or race 3 (compatible, host susceptible) of Phytophthora megasperma f.sp. glycinea and total callose was determined at various times after inoculation. From 4 h onward, total callose was significantly higher in roots showing the resistant rather than the susceptible response. Local callose deposition in relation to location of fungal hyphae was determined in microtome sections by its specific fluorescence with sirofluor and was quantified on paper prints with an image-analysis system. Callose deposition, which occurs adjacent to hyphae, was found soon after inoculation (2, 3 and 4 h post inoculation) only in roots displaying the resistant response, and was also higher at 5 and 6 h after inoculation in these resistant roots than in susceptible roots. Early callose deposition in the incompatible root-fungus reaction could be a factor in resistance of soybean against P. megasperma.
The compositions of lipopolysaccharides from the photoheterotrophic budding Rhodomicrobium vannielii strains DSM 162, Rm5, E3 and 2/1 are reported. Common constituents of these lipopolysaccharides are glucose, mannose, glucosamine, glucuronic and galacturonic acids, 2-keto-3-deoxyoctonate (KDO) and the fatty acids 3-OH-C16:0, 3-OH-C14:0, C14:0, Δ14-C22:1, aside from strain specific differences. Two different, medium-dependent growth forms of strain DSM 162 are described. The vitamin/ yeast extract-concentration in the medium and/or the growth temperature were found as factors triggering the different growth forms. Lipopolysaccharides of the two growth forms had only quantitative differences in composition. Lipopolysaccharide from swarmer cells of strain Rm5 showed a chemical composition comparable to that of chain cells and from simple cycle cells of the same strain.
The rigid layer and peptidoglycan fractions from two strains (ATCC 17100 and Rm 5) of the budding phototrophic Rhodomicrobium vannielii were isolated. Rigid layers of both strains contain protein in addition to peptidoglycan. They were free of polysaccharides and fatty acids. The respective peptidoglycan fractions contain glucosamine, muramic acid, ʟ-and ᴅ-alanine, ᴅ-glutamic and meso-diaminopimelic acid in approximately equimolar ratios except for a signifi cant lower relative ᴅ-alanine content. Analysis of partial acid hydrolysates revealed A 1 γ-type structure of Rhodomicrobium vannielii peptidoglycan (shown with strain ATCC 17100). An about 10-30% lack of N-acetylation of glucosamine was indicated. The degree of cross-linkage was found to be about 60% .
No differences in peptidoglycan composition and degree of cross-linkage were found between swarmer-and chain-cells as examined with strain Rm 5.
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