Rapid identification of Actinomycetaceae and related bacteria.
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Identification of new isolates belonging to the family Actinomycetaceae requires extensive numbers of biochemical tests, supplemented with gas-liquid chromatography determination of fermentation end products and, often, analysis of cell wall composition. This paper describes the results of the testing of 162 strains of Actinomycetaceae and related taxa for 20 different enzymatic activities including phosphatases, esterases, aminopeptidases, and glycosidases. The results of all tests were read after 4 h of incubation. The results obtained in the study provide significant new information on the biochemical properties of these groups of bacteria. An identification scheme based upon 13 selected tests, which allow the identification of these groups of bacteria within 4 h, is proposed. (+info)
Effects of antibiotics on metabolism of peptidoglycan, protein, and lipids in Bifidobacterium bifidum subsp. pennsylvanicus.
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The formation of cell envelope components of Bifidobacterium bifidum subsp. pennsylvanicus was studied by measuring the incorporation of [(3)H]glycine, (14)C-labeled fatty acids, and N-benzoyl-[(14)C]glucosamine into the membrane protein, membrane lipids, and cell wall peptidoglycan, respectively. Inhibition of peptidoglycan synthesis by antibiotics (penicillin G, vancomycin, d-cycloserine, and bacitracin) and by the omission of glucosamine-containing growth factors caused a marked decrease in glycine incorporation into cellular as well as membrane protein, which was accompanied by a considerable enhancement of fatty acid incorporation. The uncoupling of protein and lipid synthesis led to the release of marked amounts of lipids from the cell under these conditions. Arrestment of protein synthesis by antibiotics (chloramphenicol, tetracycline, and actinomycin D) decreased peptidoglycan and lipid synthesis only partially, but did not lead to lipid release. Mg(2+) deficiency of the medium caused about 60% inhibition of growth and lipid synthesis, but protein synthesis and especially peptidoglycan synthesis were much less inhibited. Staphylococcin 1580 arrested the growth and also the synthesis of protein and peptidoglycan. However, the synthesis and turnover of lipids were considerably increased and a release of large amounts of lipids was observed. Peptidoglycan and cellular protein did not show any turnover either during normal growth or after the inhibition of cell wall and protein synthesis. (+info)
Characterization and cloning of celR, a transcriptional regulator of cellulase genes from Thermomonospora fusca.
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CelR, a protein that regulates transcription of cellulase genes in Thermomonospora fusca (Actinomycetaceae) was purified to homogeneity. A 6-kilobase NotI-SacI fragment of T. fusca DNA containing the celR gene was cloned into Esherichia coli and sequenced. The celR gene encodes a 340-residue polypeptide that is highly homologous to members of the GalR-LacI family of bacterial transcriptional regulators. CelR specifically binds to a 14-base pair inverted repeat, which has sequence similarity to the binding sites of other family members. This site is present in regions upstream of all six cellulase genes in T. fusca. The binding of CelR to the celE promoter is inhibited specifically by low concentrations of cellobiose (0.2-0.5 mM), the major end product of cellulases. The other sugars tested did not affect binding at equivalent or 50-fold higher concentrations. The results suggest that CelR may act as a repressor, and that the mechanism of induction involves a direct interaction of CelR with cellobiose. (+info)
Denitrobacterium detoxificans gen. nov., sp. nov., a ruminal bacterium that respires on nitrocompounds.
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A new group of anaerobic, Gram-positive, high G + C (56-60 mol%) bacteria was isolated from the bovine rumen. Of four strains characterized, all were non-motile and none produced spores. The isolates did not produce indole or H2S and did not hydrolyse gelatin. Cells of each strain exhibited similar rod-shaped morphology (0.5-1.0 x 1.0-1.5 microns) although bulbous ends were sometimes present. None of the four strains were able to grow via oxidation of a variety of potentially fermentable substrates but rather obtained energy for growth via anaerobic respiration processes, oxidizing hydrogen, formate or lactate for reduction of various oxidized nitrogen compounds. Trimethylamine oxide and DMSO were also used as electron acceptor. All four strains shared greater than 99% 16S rRNA gene sequence identity. The closest match found between the 16S rRNA gene sequence of all four strains, NPOH1T, NPOH2, NPOH3 and MAJ1, to sequences available in GenBank was that of Coriobacterium glomerans (86% sequence similarity), a phenotypically dissimilar anaerobe within the class Actinobacteria. To accommodate these bacteria the creation of a new genus and species, Denitrobacterium detoxificans, for placement within the family Coriobacteriaceae is proposed. The type strain, NPOH1T (ATCC 700546T), grew equally well over a narrow range of incubation temperatures tested (32-39 degrees C). (+info)
A novel actinomycete from sugar-cane bagasse: Saccharopolyspora hirsuta gen. et. sp. nov.
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A new species of nocardioform actinomycete isolated from spontaneously heated sugar-cane bagasse is described as Saccharopolyspora hirsuta gen. et sp. nov. It has affinities with species of both Nocardia and Actinomadura but can be distinguished from both genera by its morphology, sporulation, wall and lipid analyses, antibiotic resistance, degradation and carbon utilzation tests. (+info)
Arcanobacterium pluranimalium sp. nov., isolated from porpoise and deer.
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Two strains of a previously undescribed Arcanobacterium-like bacterium were isolated from a dead harbour porpoise and a dead sallow deer. Biochemical testing and PAGE analysis of whole-cell proteins indicated that the strains were phenotypically closely related to each other and distinct from previously described Actinomyces and Arcanobacterium species. Comparative 16S rRNA gene sequencing studies showed the bacterium to be a hitherto unknown subline within the genus Arcanobacterium. Based on phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium be classified as Arcanobacterium pluranimalium sp. nov. The type strain of Arcanobacterium pluranimalium is CCUG 42575T (= CIP 106442T). (+info)
Cloning, expression, and characterization of a neuraminidase gene from Arcanobacterium pyogenes.
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Arcanobacterium pyogenes is an opportunistic pathogen, associated with suppurative infections in domestic animals. In addition to pyolysin, a pore-forming, cholesterol-binding toxin, A. pyogenes expresses a number of putative virulence factors, including several proteases and neuraminidase activity. A 3,009-bp gene, nanH, was cloned and sequenced and conferred neuraminidase activity on an Escherichia coli host strain. The predicted 107-kDa NanH protein displayed similarity to a number of bacterial neuraminidases and contained the RIP/RLP motif and five copies of the Asp box motif found in all bacterial neuraminidases. Recombinant His-tagged NanH was found to have pH and temperature optima of 5.5 to 6.0 and 55 degrees C, respectively. Insertional deletion of the nanH gene resulted in the reduction, but not absence, of neuraminidase activity, indicating the presence of a second neuraminidase gene in A. pyogenes. NanH was localized to the A. pyogenes cell wall. A. pyogenes adhered to HeLa, CHO, and MDBK cells in a washing-resistant manner. However, the nanH mutant was not defective for adherence to epithelial cells. The role of NanH in host epithelial cell adherence may be masked by the presence of a second neuraminidase in A. pyogenes. (+info)
Structure of the major glycolipid from Rothia dentocariosa.
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Structural studies of the major glycolipid isolated from Rothia dentocariosa were carried out by specific chemical degradation and nuclear magnetic resonance spectroscopy. The glycolipid was found to be a dimannosylacylmonoglyceride in which the carbohydrate part was the glycerol-linked dimannoside alpha-D-Manp-(1-->3)-alpha-D-Manp-(1-->3)-sn-Gro, and the internal mannose was esterified at C-6 by fatty acid residue. The other fatty acyl chain substituted the primary methylene position of glycerol. The occurrence of this glycolipid is limited to the related microorganisms. The structural characteristics can facilitate the differentiation of some genera. (+info)