Characterisation of aerobic gram-negative bacteria from subgingival sites of dogs--potential bite wound pathogens.
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Ninety-eight aerobic, gram-negative bacterial isolates from subgingival samples from family-owned dogs with naturally occurring periodontitis were characterised phenotypically by conventional biochemical testing, by cellular fatty acid profiling and by the use of commercial identification systems. The majority (48, 81%) of the fermentative isolates but only 18% of the non-fermenters were identified by conventional biochemical testing alone. With additional cellular fatty acid profiling, another 7 (12%) fermentative and 23 (59%) non-fermentative isolates were identified to genus or group level. Cellular fatty acid analysis was essential for the identification of most non-fermenters, many of which are difficult to identify due to a paucity of positive reactions in routine biochemical tests. Commercial identification systems were less useful and did not contribute to further identification of these problematic isolates. This study underlines the difficulties encountered in the identification of canine oral bacteria--a group of potential bite wound pathogens--and presents schemes for microbiology laboratories to characterise such isolates. (+info)
Polyphasic identification of Bacillus and Brevibacillus strains from clinical, dairy and industrial specimens and proposal of Brevibacillus invocatus sp. nov..
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Thirty-three clinical, dairy and industrial isolates of aerobic endospore-forming bacteria which were unreactive in routine identification tests were characterized genotypically by using amplified rDNA restriction analysis (ARDRA), 16S rDNA sequencing and DNA-DNA reassociation, and phenotypically by using fatty acid methyl ester (FAME) analysis, SDS-PAGE of whole-cell proteins, API Biotype 100 assimilation tests and 16 other routine phenotypic tests. Three isolates were identified as strains of Bacillus badius, 12 as Brevibacillus agri, including 3 strains associated with an outbreak of waterborne illness, 4 as Brevibacillus centrosporus and 2 as Brevibacillus parabrevis; 12 strains contaminating an antibiotic production plant were recognized as members of a new species, for which the name Brevibacillus invocatus is proposed, with the type strain LMG 18962T (= B2156T = CIP 106911T = NCIMB 13772T). (+info)
Endometriosis is associated with an altered profile of intestinal microflora in female rhesus monkeys.
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BACKGROUND: The intestinal microflora provide a strong defence against intestinal pathogens, and may be altered in inflammatory conditions that impact the gut, such as endometriosis. Therefore, intestinal bacteria shed from rhesus monkeys with endometriosis were compared with age-matched healthy controls. A second study assessed the prevalence of intestinal inflammation in female monkeys to determine whether endometriosis is associated with an increased likelihood of intestinal inflammation. METHODS: Differential and selective agars were used to enumerate total and Gram-negative aerobic and facultatively anaerobic bacteria, as well as Lactobacilli, from female monkeys with or without endometriosis. In addition, the prevalence of intestinal inflammation in monkeys with or without endometriosis was determined in a retrospective analysis of necropsy reports. RESULTS: Monkeys with endometriosis had a significantly different profile of shed microflora. Endometriosis was associated with lower Lactobacilli concentrations and higher Gram-negative bacteria concentrations. Moreover, there was a higher prevalence of intestinal inflammation in monkeys with endometriosis in comparison to healthy controls. CONCLUSIONS: Endometriosis is associated with an altered profile of intestinal microflora in rhesus monkeys. Although the exact mechanisms linking endometriosis and the microflora are unknown, it is possible that the microflora were affected by endometriosis-associated intestinal inflammation. (+info)
Gelidibacter mesophilus sp. nov., a novel marine bacterium in the family Flavobacteriaceae.
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Two Gram-negative, aerobic, heterotrophic, marine bacteria, isolated from Mediterranean sea water off the coast near Valencia (Spain), were the object of this study. These non-motile, yellow-pigmented, rod-shaped strains have been studied by means of DNA-DNA hybridization, 16S rRNA sequencing and cultural and physiological features. Phylogenetic analysis showed that both strains belong to the phylum Cytophaga-Flavobacterium-Bacteroides, and their closest neighbour is the psychrophilic bacterium Gelidibacter algens. The two strains differ from G. algens in their mesophilic behaviour, hydrolytic pattern and use of different carbon sources. There is 31% DNA-DNA hybridization between the proposed type strain and G. algens, and both isolates show 97.5% 16S rDNA similarity to G. algens. They represent a novel species of the genus Gelidibacter, for which the name Gelidibacter mesophilus sp. nov. is proposed, with strain 2SM29T (= CECT 5103T = DSM 14095T) as the type strain. (+info)
Structural analysis of the extracellular polysaccharide produced by Sphaerotilus natans.
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An extracellular polysaccharide (EPS) was recovered and purified from the culture fluid of a sheathed bacterium, Sphaerotilus natans. Glucose, rhamnose, and aldobiouronic acid were detected in the acid hydrolysate of EPS by thin-layer chromatography (TLC). The aldobiouronic acid was found to be composed of glucuronic acid and rhamnose by TLC and gas-liquid chromatography analyses of the corresponding neutral disaccharide. The structure of EPS was identified by methylation linkage analysis and nuclear magnetic resonance. Additionally, partial acid hydrolysates of EPS were prepared and put through fast atom bombardment-mass spectrometry to determine the sugar sequence of EPS. The resulting data showed that EPS produced by S. natans is a new gellan-like polysaccharide constructed from a tetrasaccharide repeating unit, as shown below. -->4)-alpha-D-Glcp-(1-->2)-beta-D-GlcA p-(1-->2)-alpha-L-Rha p-(1-->3)-beta-L-Rha p-(1-->. (+info)
Iron transport and signaling in Escherichia coli.
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Bacteria solve the iron supply problem caused by the insolubility of Fe(3+) by synthesizing iron-complexing compounds, called siderophores, and by using iron sources of their hosts, such as heme and iron bound to transferrin and lactoferrin. Escherichia coli, as an example of Gram-negative bacteria, forms sophisticated Fe(3+)-siderophore and heme transport systems across the outer membrane. The crystal structures of three outer membrane transport proteins now allow insights into energy-coupled transport mechanisms. These involve large long-range structural transitions in the transport proteins in response to substrate binding, including substrate gating. Energy is provided by the proton motive force of the cytoplasmic membrane through the activity of a protein complex that is inserted in the cytoplasmic membrane and that contacts the outer membrane transporters. Certain transport proteins also function in siderophore-mediated signaling cascades that start at the cell surface and flow to the cytoplasm to initiate transcription of genes encoding proteins for transport and siderophore biosynthesis. (+info)
Paenibacillus koleovorans sp. nov., able to grow on the sheath of Sphaerotilus natans.
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Two bacterial strains that are able to grow specifically on the sheath of a sheathed filamentous bacterium, Sphaerotilus natans, were isolated from soil samples. The sheath-degrading organisms, designated strains TB(T) and TK, are facultatively anaerobic and form endospores. The Gram reaction was negative at all stages of cultivation. The optimum growth temperature and pH were 30 degrees C and pH 7. The DNA G+C content was 54.0-55.8 mol%. MK-7 was the predominant menaquinone and anteiso-C15:0 was the major fatty acid. Phylogenetic analysis based on the 16S rDNA sequences revealed that the isolates were closely related to Paenibacillus chondroitinus, Paenibacillus alginolyticus, Paenibacillus koreensis, Paenibacillus validus, Paenibacillus larvae subsp. larvae and P. larvae subsp. pulvifaciens. The sequences were found to contain consensus sequences characteristic of all Paenibacillus species. The isolates were able to lyse and utilize the purified sheath of S. natans as the sole carbon and energy source. Acid was not produced from common carbon sources, allowing easy distinction from other members of Paenibacillus. It is concluded that the two strains represent a novel Paenibacillus species, for which the name Paenibacillus koleovorans sp. nov. is proposed. The type strain is strain TB(T) (= JCM 11186T = IAM 14926T = KCTC 13912T). (+info)
Thermostable polynucleotide phosphorylases from Bacillus stearothermophilus and Thermus aquaticus.
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Polynucleotide phosphorylase from Bacillus stearothermophilus has been purified to homogeneity. Polyacrylamide gel electrophoresis run under denaturing conditions indicates that the enzyme is a tetramer with subunits of apparent molecular weight 51,000 daltons. A partial purification of polynucleotide phosphorylase from Thermus aquaticus has also been effected. The two enzymes show similar catalytic properties, which differ little from those of mesophilic polynucleotide phosphorylases. The use of thermostable polynucleotide phosphorylases for in vitro nucleic acid synthesis is discussed. (+info)