Application of temperature-gradient gel electrophoresis in taxonomy of coryneform bacteria.
(1/1707)
Strains belonging to the Gram-positive coryneform soil bacteria were screened genotypically by temperature-gradient gel electrophoresis (TGGE). This method allows the sequence-specific separation of amplified fragments of 16S rRNA genes. A total of 115 reference strains representing the majority of the species of the genera Aeromicrobium, Agromyces, Arthrobacter, Aureobacterium, Cellulomonas, Curtobacterium, Nocardioides and Terrabacter were characterized. Depending on the genus investigated, the resolution limit of the technique appeared to be at the species or genus level or intermediate between the two. Aberrant TGGE profiles of strains within particular taxa revealed genomic heterogeneity and generic misclassification of nine strains studied. Beyond that, indications of 16S rRNA gene heterogeneity were found within the genomes of three Curtobacterium strains. The misclassifications revealed by TGGE were confirmed using whole-cell fatty acid methyl ester analysis and subsequent comparison with a database. TGGE has been demonstrated to be a useful tool in bacterial taxonomy. (+info)
New genus-specific primers for the PCR identification of members of the genera Pseudonocardia and Saccharopolyspora.
(2/1707)
Members of the family Pseudonocardiaceae are difficult to identify on the basis of their micromorphology only. The biochemical characterization of each new isolate is a painstaking and time-consuming task which cannot always be undertaken when handling large numbers of strains as is the case in natural product screening programmes. In this study, two sets of genus-specific oligonucleotides were designed which allow rapid detection of members of the genera Pseudonocardia and Saccharopolyspora by means of PCR-specific amplification. The genus specificity of these primers was validated on a wide range of collection strains and the primers were subsequently used to study a group of 106 wild-type isolates that possessed morphological characteristics of the family. Out of this group, 51 strains could be identified as members of the genus Pseudonocardia and only nine isolates could be assigned to the genus Saccharopolyspora. The diversity indicated by whole-cell fatty acid profiles of both wild-type and reference strains was compared with that identified using the oligonucleotide primers. The partial 16S rDNA sequencing of representative wild-type strains was used to validate their genus assignment by PCR-specific amplification. This study shows the industrial usefulness of the application of these direct identification tools as well as the complementary use of two sources of data, PCR-specific amplification results and fatty acid composition, to assess the diversity of a microbial population. (+info)
Reclassification of Brevibacterium oxydans (Chatelain and Second 1966) as Microbacterium oxydans comb. nov.
(3/1707)
Phylogenetic and chemotaxonomic analyses indicate that Brevibacterium oxydans is closely related to species of the genus Microbacterium, namely Microbacterium liquefaciens, Microbacterium luteolum and Microbacterium saperdae. DNA-DNA reassociation values of less than 60% between Brevibacterium oxydans and these three Microbacterium species support the distinctness of this misclassified Brevibacterium species, which is reclassified as Microbacterium oxydans comb. nov. (+info)
Structure of actinotetraose hexatiglate, a unique glucotetraose from an actinomycete bacterium.
(4/1707)
An Actinomycete strain A499 belonging to the genera Amycolatopsis or Amycolata isolated from a Western Australian soil sample produced the cyclic decapeptide antibiotic quinaldopeptin (1), together with the actinotetraose hexatiglate (2), the hexa-ester of a novel non-reducing glucotetraose. (+info)
IC202A, a new siderophore with immunosuppressive activity produced by Streptoalloteichus sp. 1454-19. I. Taxonomy, fermentation, isolation and biological activity.
(5/1707)
IC202A, a new immunosuppressive compound, was isolated from the culture filtrate of Streptoalloteichus sp. 1454-19. It showed a suppressive effect on mixed lymphocyte culture reaction with an IC50 value of 3.6 microg/ml and mitogen induced lymphocyte blastogenesis in vitro. (+info)
IC202A, a new siderophore with immunosuppressive activity produced by Streptoalloteichus sp. 1454-19. II. Physico-chemical properties and structure elucidation.
(6/1707)
IC202A (1) was isolated from the culture filtrate of Streptoalloteichus sp. 1454-19. The structure of 1 was determined by spectral analysis including a variety of two-dimentional NMR and FAB-MS experiments. IC202A is a ferrioxamine-related compound containing a butylidene N-oxide function. (+info)
Growth and production kinetics of a teicoplanin producing strain of Actinoplanes teichomyceticus.
(7/1707)
The growth and production kinetics of a teicoplanin producing strain of Actinoplanes teichomyceticus (ATCC 31121) was investigated during batch cultivations on defined media. The growth was characterised by two exponential growth phases (EGPs), with a higher specific growth rate in the first than in the second phase. Also the specific rate of formation of teicoplanin was significantly lower in the second phase than in the first phase. This two-phased growth pattern was suggested to be caused by inhibition of growth by teicoplanin accumulated. Furthermore high concentrations of ammonia or phosphate reduced both the specific growth rate in the first EGP and the total production of teicoplanin. (+info)
Formation of hydride-Meisenheimer complexes of picric acid (2,4, 6-trinitrophenol) and 2,4-dinitrophenol during mineralization of picric acid by Nocardioides sp. strain CB 22-2.
(8/1707)
There are only a few examples of microbial conversion of picric acid (2,4,6-trinitrophenol). None of the organisms that have been described previously is able to use this compound as a sole source of carbon, nitrogen, and energy at high rates. In this study we isolated and characterized a strain, strain CB 22-2, that was able to use picric acid as a sole source of carbon and energy at concentrations up to 40 mM and at rates of 1.6 mmol. h(-1). g (dry weight) of cells(-1) in continuous cultures and 920 micromol. h(-1). g (dry weight) of cells(-1) in flasks. In addition, this strain was able to use picric acid as a sole source of nitrogen at comparable rates in a nitrogen-free medium. Biochemical characterization and 16S ribosomal DNA analysis revealed that strain CB 22-2 is a Nocardioides sp. strain. High-pressure liquid chromatography and UV-visible light data, the low residual chemical oxygen demand, and the stoichiometric release of 2.9 +/- 0.1 mol of nitrite per mol of picric acid provided strong evidence that complete mineralization of picric acid occurred. During transformation, the metabolites detected in the culture supernatant were the [H-]-Meisenheimer complexes of picric acid and 2,4-dinitrophenol (H--DNP), as well as 2,4-dinitrophenol. Experiments performed with crude extracts revealed that H--DNP formation indeed is a physiologically relevant step in picric acid metabolism. (+info)