ABSTRACT
Xanthomonas maltophilia (later synonym of Pseudomonas maltophilia), an ubiquitous species, is known to show proteolytic and lipolytic activities. A cell-bound esterase which hydrolyzes beta-naphthyl acetate during growth has been extracted from a strain isolated from soil. Because of its strongly hydrophobic character, the enzyme could be efficiently solubilized only by Triton X-100. This nonionic detergent must be added in polyacrylamide gels to permit migration. Polyclonal rabbit antibodies raised against the Triton-soluble esterase complex were used to localize the enzyme at the ultrastructural level. Electron microscopy of cell sections of this organism and immunogold labeling demonstrated that the enzyme was located on the outer membrane. Such an envelope-bound esterase may produce assimilable substrates for X. maltophilia which can grow in various environments.
Subject(s)
Esterases/analysis , Soil Microbiology , Xanthomonas/enzymology , Animals , Antibody Specificity , Cell Membrane/enzymology , Cell Membrane/ultrastructure , Electrophoresis, Polyacrylamide Gel , Esterases/immunology , Hydrogen-Ion Concentration , Immunodiffusion , Immunoelectrophoresis , Immunohistochemistry , Male , Microscopy, Electron , Rabbits , Xanthomonas/ultrastructureABSTRACT
Pseudomonas maltophilia has been identified in the rhizosphere of several cultured plants: cabbage, rape, mustard, corn, beet. In comparison with nonrhizospheric soil, all the rhizospheric samples analysed contain more of this Pseudomonas and the most important stimulation is supplied by cruciferous plants. The possible relation with greater amounts of sulphur-containing amino acids in root secretion is suggested.
Subject(s)
Plants/microbiology , Pseudomonas/growth & development , Soil Microbiology , Amino Acids/physiology , Plant Physiological Phenomena , SeasonsABSTRACT
The taxonomic position of some telluric non-fermenting Gram-negative bacteria collected into a phenon representing about a quarter of the soil isolates by an earlier numerical analysis is specified. The Shapiro--Chargaff coefficient determined by thermal-transition curves of the DNA and their hybridization by nitrocellulose filters method show a close affinity with Pseudomonas maltophilia.
Subject(s)
Bacteria/classification , Pseudomonas/classification , Soil Microbiology , Bacteria/analysis , DNA, Bacterial/analysis , France , Hot Temperature , Nucleic Acid Denaturation , Nucleic Acid Hybridization , Pseudomonas/analysisABSTRACT
A numerical analysis was carried out from a set of 165 telluric Gram-negative bacterial strains. The results allowed to join up 130 of them divided into eight phenons. Two of these phenons represent on their own 70% of the classified strains. The first of these phenons (52 strains) can be assimilated to the genus Pseudomonas in the fluorescent group; the second one (41 strains) offers some analogies with the Acinetobacter. A representative strain type of the latter phenon was retained for later taxonomic comparisons.