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PubMed1995

Localization of the enzymes involved in H2 and formate metabolism in Syntrophospora bryantii.

Cell-free extracts of crotonate-grown cells of the syntrophic butyrate-oxidizing bacterium Syntrophospora bryantii contained high hydrogenase activities (8.5-75.8 mumol.min-1mg-1 protein) and relatively low formate dehydrogenase activities (0.04-0.07 mumol.min-1 mg-1 protein). The KM value and threshold value of the hydrogenase for H2 were 0.21 mM and 18 microM, respectively, whereas the KM value and threshold value of the formate dehydrogenase for formate were 0.22 mM and 10 microM, respectively. Hydrogenase, butyryl-CoA dehydrogenase and 3-OH-butyryl-CoA dehydrogenase were detected in the cytoplasmic fraction. Formate dehydrogenase and CO2 reductase were membrane-bound, likely located at the outer aspect of the cytoplasmic membrane. Results suggest that during syntrophic butyrate oxidation H2 is formed intracellularly while formate is formed at the outside of the cell.

Aldehyde Oxidoreductases↗
PubMed1995

Isolation and characterization of a thermophilic sulfate-reducing bacterium, Desulfotomaculum thermosapovorans sp. nov.

Strain MLFT (T = type strain), a new thermophilic, spore-forming sulfate-reducing bacterium, was characterized and was found to be phenotypically, genotypically, and phylogenetically related to the genus Desulfotomaculum. This organism was isolated from a butyrate enrichment culture that had been inoculated with a mixed compost containing rice hulls and peanut shells. The optimum temperature for growth was 50 degrees C. The G+C content of the DNA was 51.2 mol%. Strain MLFT incompletely oxidized pyruvate, butyrate, and butanol to acetate and presumably CO2. It used long-chain fatty acids and propanediols. We observed phenotypic and phylogenetic differences between strain MLFT and other thermophilic Desulfotomaculum species that also oxidize long-chain fatty acids. On the basis of our results, we propose that strain MLFT is a member of a new species, Desulfotomaculum thermosapovorans.

DNA, Bacterial↗
PubMed1996

Sulfobacillus disulfidooxidans sp. nov., a new acidophilic, disulfide-oxidizing, gram-positive, spore-forming bacterium.

An acidophilic, disulfide-oxidizing, mesophilic, aerobic bacterium was isolated from wastewater sludge. The new organism is a gram-positive sporulated rod. It can use elemental sulfur and pyrite as sole energy sources and grows on organic substrates such as glutamate and glucose. It also grows on the following organic sulfur substrates: oxidized and reduced glutathione, cysteine, cystine, and dithio(bis)benzothiazole and clearly shows a preference for disulfide bond-containing substrates. The optimal pH of growth is between 1.5 and 2.5, depending on the substrate used, and the growth temperature range varies from 4 to 40 degrees C, with an optimal value at 35 degrees C. The G + C chromosomal DNA content was measured at 53 +/- 1 mol%. Phylogenetic analysis of 16S genes coding for rRNA sequences places the new isolate in the genus Sulfobacillus. In addition, unique phenotypic and physiologic characteristics and DNA homology values assign the isolate to a new species in the genus. Therefore, this new isolate has been named Sulfobacillus disulfidooxidans and has been assigned ATCC number 51911.

Base Composition↗
PubMed1991

Characterisation of potential adhesins of the bacterium Pasteuria penetrans, and of putative receptors on the cuticle of Meloidogyne incognita, a nematode host.

Pasteuria penetrans spores were fragmented by glass bead vortexing, producing exosporial membranes and spore fragments, which consisted of fibre bundles. Both exosporia and spore fragments are capable of host-specific attachment to the cuticle of Meloidogyne incognita, a root-knot nematode host. Putative M. incognita receptors appear to be soluble in beta-mercaptoethanol (BME) but not SDS, and are also sensitive to tryptic digestion and deglycosylation by endoglycosidase F. Polyclonal antibodies against intact spores and spore fragments of antispore antibodies produced 100% inhibition. The antibodies, however, did not show preferential staining of particular spore structures in thin section immunolabelling studies. Exposure of Pasteuria penetrans spores to HCl or urea-SDS-dithiothreitol renders them incapable of attachment to their host juveniles and extensively disrupts fibres that surround the spore core. Protein extracts from spore fragments or from exosporial membranes are identical, and urea-BME extracts from either structure, but not SDS extracts, can inhibit the attachment of spores to juveniles by 60-80%. An inhibitory BME extract from spore fragments was analysed by anion-exchange chromatography and adsorption onto host cuticle followed by immunoblotting. It appeared to contain six potential spore adhesins of approximate Mr 24-29, 38-47, 59, 89, 126, and 190 (x10(3)). Lectin affinity blotting with wheat germ agglutinin and concanavalin A showed that all of these proteins bear terminal N-acetylglucosamine residues and the 38-47 kDa band also bears terminal Glc/Man residues.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[Numerical taxonomy of a thermophilic "Bacillus" species isolated from West African rice soils (author's transl)].

Fifty-seven strains of endospore-forming thermophilic bacteria, 37 of which were capable of denitrification, were isolated from rice soils of West Africa. They were compared with 17 strains of similar bacteria from culture collections, utilizing a total of 123 morphological, physiological and biochemical characteristics. A numerical analysis was performed using the complete linkage-clustering method and the Khi2 test. Seventy-five percent (55 strains) could be included in 12 groups at a taxonomic distance of 0.015. Wild strains of denitrifiers issued in phenons 8 to 12 and strains of phenon 4 (not denitrifying) were related to the named strains of phenons 1 and 7 (Bacillus stearothermophilus). Twenty-two wild strains, and 5 strains from culture collections, were only thermotolerating without growth at 65 degrees C. The strains of phenon 3 were related to the 3 named strains of B. coagulans. Phenons 5 and 6 were composed of strains related to B. circulans. The strains of phenon 2 denitrified and showed a swollen central endospore; they were closely related to B. brevis. The denitrifying thermophilic strains isolated from rice soils (phenons 8 to 12) were related to the first group (B. kaustophilus) of Walker and Wolf but their base compositions of DNA were significantly different from those found for the reference strains.

Africa, Western↗
PubMedDate not supplied

[Distribution of heterotrophic aerobic microflora and specially denitrifying and free-living nitrogen-fixing bacteria in the rhizosphere of rice (author's transl)].

The distribution of heterotrophic aerobic bacteria, actinomycetes and fungi was estimated in three samples (rhizospherical soil (SR), rhizoplane (R) and endorhizosphere (ER)) obtained from one rice seedling which had grown in pot during four mounths in a Casamance grey soil. The number of microbial populations were about the same from one sample to another: 1.1 to 2 X 10(8) bacteria, 3.3 to 8.6 X 10(6) actinomycetes and 0.2 to 8.9 X 10(4) fungi per gram of dry soil (SR) or dry roots (R and ER). The denitrifying and free-living nitrogen fixing bacteria were numerous (10(7) bacteria/g) but lower for ER where the number of actinomycetes remained high. Thirty-six bacterial strains have been isolated from every sample with the use of a grid of isolation. The Gram-negative bacteria were dominant in SR and R where they represented respectively 70 and 94% of total count. The major groups were non-sporulated Gram-variable rods (SR) and Alcaligenes-like bacteria (ER). The pseudomonads represented quite 15% of total count in the three samples. On the other hand, the frequency of endospore-forming Gram-positive bacteria was high only in R where the Bacillus group was estimated to 45% of total count. Only 5 free-living nitrogen-fixing bacterial strains had shown a denitrifying ability.

Aerobiosis↗
PubMed1983

Effective surface sterilization of gutta-percha points.

A bacteriologic investigation was conducted to determine the sterilizing effectiveness of various germicidal endodontic irrigants on gutta-percha points. It was found that most effective in surface sterilization was a 5-minute treatment using sodium hypochlorite, Zephiran, and hydrogen peroxide in concentrations of 4.50 percent, 0.53 percent, and 3.00 percent, respectively. These agents were potent against gram-positive and gram-negative bacteria as well as endospore-forming microorganisms. Fungal spores were killed only by the first two but not by the latter germicidal agents. On the other hand, ethanol, chloroform, eugenol, betadine, and Gram's iodine solution were found not to be effective for surface sterilization.

Bacteria↗
PubMed1990

L-lysine production at 50 degrees C by mutants of a newly isolated and characterized methylotrophic Bacillus sp.

The amino acid L-lysine was produced from homoserine auxotrophic and S-(2-aminoethyl)-L-cysteine-resistant mutants of a newly isolated gram-positive methylotrophic bacterium, capable of growth on methanol at 60 degrees C. The temperature optimum for growth was between 50 and 53 degrees C. These aerobic, gram-positive, endospore-forming, rod-shaped bacteria required biotin and vitamin B12 for growth. Extracts of the bacteria grown on methanol lacked hydroxypyruvate reductase and contained hexulose 6-phosphate synthase activity. Therefore, these bacteria were considered to be type I methylotrophic bacteria of the genus Bacillus. Fed-batch fermentations resulted in cell densities of 50 g of cell dry weight per liter. Biomass yields on carbon, nitrogen, phosphate, and sulfate were determined. Generation of homoserine auxotrophic and amino acid analog-resistant mutants resulted in L-lysine concentrations of nearly 20 g/liter in fed-batch fermentations.

Bacillus↗
PubMed1992

Isolation and characterization of an anaerobic chlorophenol-transforming bacterium.

An obligately anaerobic bacterium which transforms several chlorinated phenols was isolated. Dechlorination of the substituents ortho to the phenolic OH group was preferred, while removal of a meta-substituted chlorine was observed only with 3,5-dichlorophenol. The bacterium was a gram-positive, endospore-forming, motile, slightly curved rod. Sulfate was not reduced. Nitrate was reduced via nitrite to ammonium. The bacterium is related to the genus Clostridium. The highest growth rate was obtained in a medium containing pyruvate and yeast extract. Pyruvate supported growth as the sole source of carbon, and the fermentation of pyruvate produced almost equimolar amounts of acetate.

Bacteria, Anaerobic↗
PubMedDate not supplied

[Isolation of a large aerobic sporulated sheathed bacteria from soil by elective culture].

Eleven endospore-forming strains of a probably unknown species of Bacillus were isolated from samples of pasteurized soil by aerobic enrichment culture at 32 degrees C in a minimal medium containing benzoate, p-hydroxybenzoate or cyclohexane carboxylate, as source of carbon and energy. They grew in the form of unbranched, flexible filaments 1.8 micrograms in diameter and sometimes more than 1,000 micrograms in length. The organism was not coenocytic because transverse partitions were visible. The endospores were oval (1.8 x 2.2 micrograms) and did not deform the filaments. A thin, translucid sheath was present. The 11 strains were prototrophic, used benzoate and acetate as sources of carbon and energy but did not grow in common peptone media. Only the isolation technique has been described here.

Bacillus↗
PubMed1985

Further studies on thymidine kinase: distribution pattern of the enzyme in bacteria.

Various micro-organisms (131 strains of 73 species) were studied for their ability to produce thymidine kinase (TK; EC 2.7.1.21). Taking the specific TK activity of Escherichia coli K12 [specific activity of sonicated cell extracts 95-194 pmol min-1 (mg protein)-1] as 100%, the test organisms had the following relative specific TK activities. In the Gram-positive cocci, Staphylococcus aureus (21-84%) showed higher activity than Staph. epidermidis (1-20%) and Streptococcus (1-7%) except for one strain of Strep. pyogenes (29%). Neisseria sicca, a Gram-negative coccus, lacked TK. Gram-positive endospore-forming rods showed significant activity (Bacillus, 13-51%; Clostridium perfringens, 9-18%) except for one strain of B. megaterium (2%) and C. difficile (1-3%). Among the Gram-positive asporogenous rods, Listeria monocytogenes and six species of Lactobacillus (especially L. brevis, L. buchneri and L. casei) had moderate to high activity (23-348%) but L. acidophilus, L. bulgaricus, L. lactis and L. cellobiosus had low activity (0-8%). Of the species of Pseudomonas studied, most lacked TK but Ps. fluorescens and Ps. maltophilia had significant TK activity (15-53%). Of the Gram-negative facultative anaerobes, Vibrio lacked TK, while Enterobacteriaceae, including Salmonella (148-1120%), Escherichia (59-141%), Klebsiella (78-299%) and Serratia (61-110%), had a high activity. Proteus had a somewhat lower activity (0-34%) except for 'Pr. rettgerella' (307%). Propionibacterium and Bifidobacterium and related organisms other than Streptomyces, Nocardia, Rhodococcus, Corynebacterium and Mycobacterium lacked TK. The seven species of Candida tested, and Cryptococcus neoformans, essentially lacked TK.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinomycetales↗
PubMed1993

Dichloromethane as the sole carbon source for an acetogenic mixed culture and isolation of a fermentative, dichloromethane-degrading bacterium.

Dichloromethane (DCM) is utilized by the strictly anaerobic, acetogenic mixed culture DM as a sole source of carbon and energy for growth. Growth with DCM was linear, and cell suspensions of the culture degraded DCM with a specific activity of 0.47 mkat/kg of protein. A mass balance of 2 mol of chloride and 0.42 mol of acetate per mol of DCM was observed. The dehalogenation reaction showed similar specific activities under both anaerobic and aerobic conditions. Radioactivity from [14C]DCM in cell suspensions was recovered largely as 14CO2 (58%), [14C]acetate (23%), and [14C]formate (11%), which subsequently disappeared. This suggested that formate is a major intermediate in the pathway from DCM to acetate. Efforts to isolate from culture DM a pure culture capable of anaerobic growth with DCM were unsuccessful, although overall acetogenesis and the partial reactions are thermodynamically favorable. We then isolated bacterial strains DMA, a strictly anaerobic, gram-positive, endospore-forming rod, and DMB, a strictly anaerobic, gram-negative, endospore-forming homoacetogen, from culture DM. Both strain DMB and Methanospirillum hungatei utilized formate as a source of carbon and energy. Coculture of strain DMA with either M. hungatei or strain DMB in solid medium with DCM as the sole added source of carbon and energy was observed. These data support a tentative scheme for the acetogenic fermentation of DCM involving interspecies formate transfer from strain DMA to the acetogenic bacterium DMB or to the methanogen M. hungatei.

Bacteria, Anaerobic↗
PubMed1994

Mineralization of monofluorobenzoate by a diculture under sulfate-reducing conditions.

A mesophilic, dehalogenating, sulfate-reducing diculture was isolated from an anaerobic lake sediment. One strain of the diculture is proposed to be an endospore-forming Desulfotomaculum species, the second strain was a vibrioid, motile and non-sporeforming species which is tentatively assigned to the genus Desulfovibrio. The diculture was able to mineralize 4- and 2-fluorobenzoate both isomers being incompletely oxidized with the release of acetate, which was subsequently used by both sulfate-reducing strains. Other electron donors used for growth included benzoate, 3- and 4-hydroxybenzoate, protocatechuate, catechol, phenol, 2,5-dimethoxyphenol, fatty acids up to C8, malate and pyruvate. The culture obtained from a freshwater habitat grew optimally at NaCl concentrations of 0.3-0.5 g l-1, 33-37 degrees C, and pH 7.4. Our experiments showed that certain fluorinated aromatic hydrocarbons could serve as sole sources of carbon and energy for sulfate-reducing bacteria.

Benzoates↗
PubMed1991

Acetonema longum gen. nov. sp. nov., an H2/CO2 acetogenic bacterium from the termite, Pterotermes occidentis.

A previously undescribed, H2-oxidizing CO2-reducing acetogenic bacterium was isolated from gut contents of the wood-feeding termite, Pterotermes occidentis. Cells of representative strain APO-1 were strictly anaerobic. Gram-negative, endospore-forming motile rods which measured 0.30-0.40 x 6-60 microm. Cells were catalase positive, oxidase negative, and had 51.5 mol percent G + C in their DNA. Optimum conditions for growth on H2 + CO2 were at 30-33 degrees C and pH (initial) 7.8, and under these conditions cells formed acetate according to the equation: 4 H2 + 2 CO2----CH3COOH + 2 H2O. Other energy sources supporting good growth of strain APO-1 included glucose, ribose, and various organic acids. Acetate and butyrate were major fermentation products from most organic compounds tested, however propionate, succinate, and 1,2-propanediol were also formed from some substrates. Based on comparative analysis of 16S rRNA nucleotide sequences, strain APO-1 was related, to but distinct from, members of the genus Sporomusa. Moreover, physiological and morphological differences between strain APO-1 and the six known species of Sporomusa were significant. Consequently, it is proposed herewith that a new genus, Acetonema, be established with strain APO-1 as the type strain of the new species, Acetonema longum. A. longum may contribute to the nutrition of P. occidentis by forming acetate, propionate and butyrate, compounds which are important carbon and energy sources for termites.

Acetates↗
PubMed1993

Characterization of two Metabacterium sp. from the gut of rodents. 1. Morphology and histochemical examination of a new Metabacterium sp. from the gut of the European hamster (Cricetus cricetus)

A new giant Gram-negative non-cultivatable symbiotic endospore-forming bacterium was found in the gut of the European hamster. This "Metabacterium" sp., provisionally named "Metabacterium criceti", sp. n., has a length of approximately 20 microns and thickness of 4 microns. It forms 1 to 2 cylindrical endospores, approximately 9 microns long and 1.4 microns thick. TEM-micrographs show a cell wall structure characteristic of Gram-negative bacteria. Vegetative cells are filled with granules 0.3 micron in diameter which resemble starch granules. The reproduction occurs with binary fission and by formation of two endospores. Of thirteen biochemical components sought, four, i.e. glycogen, triacylglycerols, peroxidase and alkaline phosphatase, were not found. Starch, acid mucosubstances, DNA, RNA, lipids, proteins, adenosine triphosphatase and acid phosphatase were found in different patterns, depending on the developmental stage of the bacterium. In the vegetative cell stage all these components, with the exception of starch, were found. In the endospore-bearing cell stage, only the starch-like cell component granules could be detected. In free endospores only DNA, RNA and acid phosphatase were found. Some of the components, i.e. DNA, lipids, starch-like granules, were linked to certain cell substructures, the distribution of others, viz. polysaccharides, RNA, adenosine triphosphatase and proteins was diffuse. The lipids, found only in vegetative cells, were associated with the cell wall.

Animals↗
PubMed1991

Pasteuria nishizawae sp. nov., a mycelial and endospore-forming bacterium parasitic on cyst nematodes of genera Heterodera and Globodera.

This study describes Pasteuria nishizawae sp. nov., a fourth species of the genus Pasteuria. This mycelial and endospore-forming bacterium parasitizes the adult females of cyst-forming nematodes in the genera Heterodera and Globodera. The distinct ultrastructural features and unique host range found for this bacterium separate it from two closely related species, Pasteuria penetrans, which parasitizes several species of root-knot nematodes of the genus Meloidogyne, and Pasteuria thornei, which appears to parasitize only one species of the root-lesion nematode, Pratylenchus brachyurus. Because these obligate bacterial parasites of nematodes have not been cultured axenically, the taxonomic relationships described here for each species are based mainly on developmental morphology, fine structure of the respective sporangia and endospores, and their pathogenicity on nematode species.

Animals↗
PubMed1996

Phylogenetic characterization of a novel salt-tolerant Bacillus species: description of Bacillus dipsosauri sp. nov.

The taxonomic position of a novel halophilic endospore-forming bacterium previously isolated from a desert iguana was investigated by 16S rRNA gene sequencing. Comparative sequence analyses showed the unidentified bacterium to be phylogenetically loosely associated with some other spore-forming (Bacillus pantothenticus, Sporosarcina halophila) and non-spore-forming (Marinococcus albus) halotolerant bacteria. Based on the phenotypic and phylogenetic distinctiveness of the unidentified bacterium, it is proposed that it is classified in the genus Bacillus as a new species, Bacillus dipsosauri.

Animals↗