Rawle I. Hollingsworth

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A mutant strain (39E H8) of Thermoanaerobacter ethanolicus that displayed high (8% [vol/vol]) ethanol tolerance for growth was developed and characterized in comparison to the wild-type strain (39E), which lacks alcohol tolerance (<1.5% [vol/vol]). The mutant strain, unlike the wild type, lacked primary alcohol dehydrogenase and was able to increase the(More)
Lipopolysaccharides (LPSs) isolated from several strains of Rhizobium, Bradyrhizobium, Agrobacterium, and Azorhizobium were screened for the presence of 27-hydroxyoctacosanoic acid. The LPSs from all strains, with the exception of Azorhizobium caulinodans, contained various amounts of this long-chain hydroxy fatty acid in the lipid A fractions. Analysis of(More)
Proton nuclear magnetic resonance (1H NMR) and fast atom bombardment mass spectrometric analyses were performed on enzymatically derived oligosaccharides from the acidic excreted polysaccharides (EPS) from representative bacterial strains of the pea-nodulating symbiont, Rhizobium leguminosarum (128C53, 128C63, and 300) and the clover-nodulating symbiont,(More)
exo mutants of Rhizobium meliloti SU47, which fail to secrete acidic extracellular polysaccharide (EPS), induce Fix- nodules on alfalfa. However, mutants of R. meliloti Rm41 carrying the same exo lesions induce normal Fix+ nodules. We show that such induction is due to a gene from strain Rm41, which we call lpsZ+, that is missing in strain SU47. lpsZ+ does(More)
The general view on Rhizobium chitolipooligosaccharides (CLOS) is that they are made in very low levels as diffusible molecules and are primarily secreted by the bacteria into the extracellular milieu where they interact with the host. However, the structural and predicted physicochemical properties of these amphiphilic molecules led us to postulate that(More)
Rhizobium chitolipooligosaccharides (CLOSs) are heterogeneous fatty acylated N-acetyl glucosamine oligomers with variations in both the polar (hydrophilic) oligosaccharide head group and the non-polar (hydrophobic) fatty acyl chain. They trigger root hair deformation and cortical cell divisions in legume roots during development of the nitrogen-fixing(More)
A polysaccharide depolymerase isolated from the phage lysate of Rhizobium trifolii 4S was used to fragment capsular polysaccharides (CPS) and extracellular polysaccharides (EPS) of R. trifolii 0403 into oligosaccharides. These products were analyzed for clover lectin (trifoliin A)-binding ability, effect on infection of white clover root hairs, and changes(More)
Acidic heteropolysaccharide lyases from lysates of phages 4S and BY15 grown on Rhizobium trifolii 4S and R. trifolii 0403, respectively, were used to analyze the capsular and excreted extracellular acidic polysaccharides of R. trifolii 0403. The activities of the enzymes as measured by viscometry were enhanced by the addition of calcium. The oligosaccharide(More)
The interaction between Rhizobium lipopolysaccharide (LPS) and white clover roots was examined. The Limulus lysate assay indicated that Rhizobium leguminosarum bv. trifolii (hereafter called R. trifolii) released LPS into the external root environment of slide cultures. Immunofluorescence and immunoelectron microscopy showed that purified LPS from R.(More)
Axenic seedling bioassays were performed on white clover, vetch, and alfalfa to assess the variety and dose responses of biological activities exhibited by membrane chitolipooligosaccharides (CLOSs) from wild type Rhizobium leguminosarum bv. trifolii ANU843. Subnanomolar concentrations of CLOSs induced deformation of root hairs (Had) and increased the(More)