Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Geobacillus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed2006

Expression of the ubiE gene of Geobacillus stearothermophilus V in Escherichia coli K-12 mediates the evolution of selenium compounds into the headspace of selenite- and selenate-amended cultures.

The ubiE gene of Geobacillus stearothermophilus V, with its own promoter, was cloned and introduced into Escherichia coli. The cloned gene complemented the ubiE gene deficiency of E. coli AN70. In addition, the expression of this gene in E. coli JM109 resulted in the evolution of volatile selenium compounds when these cells were grown in selenite- or selenate-amended media. These compounds were dimethyl selenide and dimethyl diselenide.

Bacillaceae↗
PubMed2006

Characteristic features in the structure and collagen-binding ability of a thermophilic collagenolytic protease from the thermophile Geobacillus collagenovorans MO-1.

A collagen-degrading thermophile, Geobacillus collagenovorans MO-1, extracellularly produces a collagenolytic protease with a large molecular mass. Complete nucleotide sequencing of this gene after gene cloning revealed that the collagenolytic protease is a member of the subtilisin family of serine proteases and consists of a signal sequence for secretion, a prosequence for maturation, a catalytic region, 14 direct repeats of 20 amino acids at the C terminus, and a region with unknown function intervening between the catalytic region and the numerous repeats. Since the unusual repeats are most likely to be cleaved in the secreted form of the enzyme, the intervening region was investigated to determine whether it participates in collagen binding to facilitate collagen degradation. It was found that the mature collagenolytic protease containing the intervening region at the C terminus bound collagen but not the other insoluble proteins, elastin and keratin. Furthermore, the intervening region fused with glutathione S-transferase showed a collagen-binding ability comparable to that of the mature collagenolytic protease. The collagen-binding ability was finally attributed to two-thirds of the intervening region which is rich in beta-strands and is approximately 35 kDa in molecular mass. In the collagenolytic protease from strain MO-1, hydrogen bonds most likely predominate over the hydrophobic interaction for collagen binding, since a higher concentration of NaCl released collagen from the enzyme surface but a nonionic detergent could not. To the best of our knowledge, this is the first report of a thermophilic collagenolytic protease containing the collagen-binding segment.

Amino Acid Sequence↗
PubMed2006

New insights into the glycosylation of the surface layer protein SgsE from Geobacillus stearothermophilus NRS 2004/3a.

The surface of Geobacillus stearothermophilus NRS 2004/3a cells is covered by an oblique surface layer (S-layer) composed of glycoprotein subunits. To this S-layer glycoprotein, elongated glycan chains are attached that are composed of [-->2)-alpha-l-Rhap-(1-->3)-beta-l-Rhap-(1-->2)-alpha-L-Rhap-(1-->] repeating units, with a 2-O-methyl modification of the terminal trisaccharide at the nonreducing end of the glycan chain and a core saccharide as linker to the S-layer protein. On sodium dodecyl sulfate-polyacrylamide gels, four bands appear, of which three represent glycosylated S-layer proteins. In the present study, nanoelectrospray ionization time-of-flight mass spectrometry (MS) and infrared matrix-assisted laser desorption/ionization orthogonal time-of-flight mass spectrometry were adapted for analysis of this high-molecular-mass and water-insoluble S-layer glycoprotein to refine insights into its glycosylation pattern. This is a prerequisite for artificial fine-tuning of S-layer glycans for nanobiotechnological applications. Optimized MS techniques allowed (i) determination of the average masses of three glycoprotein species to be 101.66 kDa, 108.68 kDa, and 115.73 kDa, (ii) assignment of nanoheterogeneity to the S-layer glycans, with the most prevalent variation between 12 and 18 trisaccharide repeating units, and the possibility of extension of the already-known -->3)-alpha-l-Rhap-(1-->3)-alpha-l-Rhap-(1--> core by one additional rhamnose residue, and (iii) identification of a third glycosylation site on the S-layer protein, at position threonine-590, in addition to the known sites threonine-620 and serine-794. The current interpretation of the S-layer glycoprotein banding pattern is that in the 101.66-kDa glycoprotein species only one glycosylation site is occupied, in the 108.68-kDa glycoprotein species two glycosylation sites are occupied, and in the 115.73-kDa glycoprotein species three glycosylation sites are occupied, while the 94.46-kDa band represents nonglycosylated S-layer protein.

Bacillaceae↗
PubMed2002

Isolation of glucocardiolipins from Geobacillus stearothermophilus NRS 2004/3a.

Glucose-substituted cardiolipins account for about 4 mol% of total phospholipid extracted from exponentially grown cells of Geobacillus stearothermophilus NRS 2004/3a. Individual glucocardiolipin species exhibited differences in fatty acid substitution, with iso-C(15:0) and anteiso-C(17:0) prevailing. The compounds were purified to homogeneity by a novel protocol and precharacterized by matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

Bacillaceae↗
PubMed2004

Effect of dimer dissociation on activity and thermostability of the alpha-glucuronidase from Geobacillus stearothermophilus: dissecting the different oligomeric forms of family 67 glycoside hydrolases.

The oligomeric organization of enzymes plays an important role in many biological processes, such as allosteric regulation, conformational stability and thermal stability. alpha-Glucuronidases are family 67 glycosidases that cleave the alpha-1,2-glycosidic bond between 4-O-methyl-D-glucuronic acid and xylose units as part of an array of hemicellulose-hydrolyzing enzymes. Currently, two crystal structures of alpha-glucuronidases are available, those from Geobacillus stearothermophilus (AguA) and from Cellvibrio japonicus (GlcA67A). Both enzymes are homodimeric, but surprisingly their dimeric organization is different, raising questions regarding the significance of dimerization for the enzymes' activity and stability. Structural comparison of the two enzymes suggests several elements that are responsible for the different dimerization organization. Phylogenetic analysis shows that the alpha-glucuronidases AguA and GlcA67A can be classified into two distinct subfamilies of bacterial alpha-glucuronidases, where the dimer-forming residues of each enzyme are conserved only within its own subfamily. It seems that the different dimeric forms of AguA and GlcA67A represent the two alternative dimeric organizations of these subfamilies. To study the biological significance of the dimerization in alpha-glucuronidases, we have constructed a monomeric form of AguA by mutating three of its interface residues (W328E, R329T, and R665N). The activity of the monomer was significantly lower than the activity of the wild-type dimeric AguA, and the optimal temperature for activity of the monomer was around 35 degrees C, compared to 65 degrees C of the wild-type enzyme. Nevertheless, the melting temperature of the monomeric protein, 72.9 degrees C, was almost identical to that of the wild-type, 73.4 degrees C. It appears that the dimerization of AguA is essential for efficient catalysis and that the dissociation into monomers results in subtle conformational changes in the structure which indirectly influence the active site region and reduce the activity. Structural and mechanistic explanations for these effects are discussed.

Amino Acid Sequence↗
PubMed2005

Two thimet oligopeptidase-like Pz peptidases produced by a collagen-degrading thermophile, Geobacillus collagenovorans MO-1.

A collagen-degrading thermophile, Geobacillus collagenovorans MO-1, was found to produce two metallopeptidases that hydrolyze the synthetic substrate 4-phenylazobenzyloxycarbonyl-Pro-Leu-Gly-Pro-D-Arg (Pz-PLGPR), containing the collagen-specific sequence -Gly-Pro-X-. The peptidases, named Pz peptidases A and B, were purified to homogeneity and confirmed to hydrolyze collagen-derived oligopeptides but not collagen itself, indicating that Pz peptidases A and B contribute to collagen degradation in collaboration with a collagenolytic protease in G. collagenovorans MO-1. There were many similarities between Pz peptidases A and B in their catalytic properties; however, they had different molecular masses and shared no antigenic groups against the respective antibodies. Their primary structures clarified from the cloned genes showed lower identity (22%). From homology analysis for proteolytic enzymes in the database, the two Pz peptidases belong to the M3B family. In addition, Pz peptidases A and B shared high identities of over 70% with unassigned peptidases and oligopeptidase F-like peptidases of the M3B family, respectively. Those homologue proteins are putative in the genome database but form two distinct segments, including Pz peptidases A and B, in the phylogenic tree. Mammalian thimet oligopeptidases, which were previously thought to participate in collagen degradation and share catalytic identities with Pz peptidases, were found to have lower identities in the overall primary sequence with Pz peptidases A and B but a significant resemblance in the vicinity of the catalytic site.

Amino Acid Sequence↗
PubMed2005

Isolation, characterization, and identification of Geobacillus thermodenitrificans HRO10, an alpha-amylase and alpha-glucosidase producing thermophile.

Thermophilic and amylolytic aerobic bacteria were isolated from soil through a selective enrichment procedure at 60 degrees C with starch as the carbon source. One of the isolates designated as HRO10 produced glucose aside from limit dextrin as the only hydrolysis product from starch and was characterized in detail. The starch-degrading enzymes produced by strain HRO10 were determined to be alpha-amylase and alpha-glucosidase. Whereas the alpha-amylase activity was detected exclusively in the culture supernatant, alpha-glucosidase occurred intracellular, extracellular, or on the surface of the bacteria depending on the growth phase. The optimum temperature and pH required for the growth of strain HRO10 were about 50 degrees C and pH 6.5 to 7.5. The strain used different carbohydrates as the carbon source, but the maximum production of alpha-amylase occurred when 1.0% (w/v) starch or dextrin was used. The use of organic vs. inorganic nitrogen favored the production of alpha-amylase in strain HRO10. The metal ions Li+, Mg2+, and Mn2+ stimulated the production of both enzymes. Identification of strain HRO10 by physiological and molecular methods including sequencing of the 16S rDNA showed that this strain belongs to the species Geobacillus thermodenitrificans. Biochemically, strain HRO10 differs from the type strain DSM 465 only in its ability to hydrolyze starch.

Bacillaceae↗
PubMed2004

High level expression of thermostable lipase from Geobacillus sp. strain T1.

A thermostable extracellular lipase of Geobacillus sp. strain T1 was cloned in a prokaryotic system. Sequence analysis revealed an open reading frame of 1,251 bp in length which codes for a polypeptide of 416 amino acid residues. The polypeptide was composed of a signal peptide (28 amino acids) and a mature protein of 388 amino acids. Instead of Gly, Ala was substituted as the first residue of the conserved pentapeptide Gly-X-Ser-X-Gly. Successful gene expression was obtained with pBAD, pRSET, pET, and pGEX as under the control of araBAD, T7, T7 lac, and tac promoters, respectively. Among them, pGEX had a specific activity of 30.19 Umg(-1) which corresponds to 2927.15 Ug(-1) of wet cells after optimization. The recombinant lipase had an optimum temperature and pH of 65 degrees C and pH 9, respectively. It was stable up to 65 degrees C at pH 7 and active over a wide pH range (pH 6-11). This study presents a rapid cloning and overexpression, aimed at improving the enzyme yield for successful industrial application.

Amino Acid Sequence↗
PubMedDate not supplied

[Thermophilic bacterium Geobacillus uralicus growth is a function of temperature and pH: a synthetic chemostat model-based kinetic analysis ].

The synthetic chemostat model (SCM), originally developed to describe nonstationary growth under widely varying concentrations of the limiting substrate, was modified to account for the effects of nontrophic factors such as temperature and pH. The bacterium Geobacillus uralicus, isolated from an ultradeep well, was grown at temperatures ranging from 40 to 75 degrees C and at pH varying from 5 to 9. The biomass kinetics was reasonably well described by the SCM, including the phase of growth deceleration observed in the first hours after a change in the cultivation temperature. In an early stage of batch growth in a neutral or alkalescent medium, bacterial cells showed reversible attachment to the glass surface of the fermentation vessel. The temperature dependence of the maximum specific growth rate (micron) was fitted using the equation micron = Aexp(lambda T)/[1 + expB[1-C/(T + 273)]], where A, lambda, B, and C are constants. The maximum specific growth rate of 2.7 h-1 (generation time, 15.4 min) was attained on a complex nutrient medium (peptone and yeast extract) at 66.5 degrees C and pH 7.5. On a synthetic mineral medium with glucose, the specific growth rate declined to 1.2 h-1 and the optimal temperature for growth decreased to 62.3 degrees C.

Bacillus↗
PubMed2006

Green polymers from Geobacillus thermodenitrificans DSM465--candidates for molecularly imprinted materials.

Novel molecular recognition materials were prepared from water soluble proteins from thermophile G. thermodenitrificans DSM465 by an alternative molecular imprinting method. Water soluble proteins from G. thermodenitrificans DSM465 were converted into the molecularly imprinted materials by adopting 9-EA as a print molecule. The molecularly imprinted protein membranes recognized As in preference to Gs. The adsorption isotherms led to the conclusion that molecular recognition sites toward As were constructed by the presence of 9-EA during the membrane preparation process. The affinity constant between As and the molecular recognition site thus constructed was determined to be 1.75 x 10(5) mol(-1) dm(3). The results obtained in the present study suggest that water soluble proteins from G. thermodenitrificans DSM465 is one of environmentally-friendly 'green' polymers to be converted into molecular recognition materials by applying an alternative molecular imprinting method.

Adsorption↗
PubMed2006

Characterization of a recombinant thermostable xylanase from deep-sea thermophilic Geobacillus sp. MT-1 in East Pacific.

A novel xylanase-producing thermophilic strain MT-1 was isolated from a deep-sea hydrothermal field in east Pacific. A xylanase gene encoding 331 amino-acid peptide from this isolate was cloned and expressed in Escherichia coli. The recombinant xylanase exhibited maximum activity at 70 degrees C and had an optimum pH of 7.0. It was active up to 90 degrees C and showed activity over a wide pH ranging from 5.5 to 10.0. The crude xylanase presented similar properties in temperature and pH to those of the recombinant xylanase. The recombinant xylanase was stable in 1 mM of enzyme inhibitors (PMSF, EDTA, 2-ME or DTT) and in 0.1% detergents (Tween 20, Chaps or Triton X-100), whereas, it was strongly inhibited by sodium dodecyl sulfate (SDS) (1 mM). In addition, its catalytic function was stable in the presence of Li(+), Na(+) or K(+). However, it was strongly inhibited by Ni(2+), Mn(2+), Co(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Al(3+) (1 or 0.1 mM). The K (m) and V (max) of the recombinant xylanase for oat spelt xylan were calculated to be 1.579 mg/ml and 289 micromol/(min x mg), respectively. Our study, therefore, presented a rapid overexpression and purification of xylanase from deep-sea thermophile aimed at improving the enzyme yield for industrial applications and scientific research.

Bacillaceae↗
PubMed2006

Isolation and characterization of a Geobacillus thermoleovorans strain from an ultra-deep South African gold mine.

A thermophilic facultative bacterial isolate was recovered from 3.2km depth in a gold mine in South Africa. This isolate, designated GE-7, was cultivated from pH 8.0, 50 degrees C water from a dripping fracture near the top of an exploration tunnel. GE-7 grows optimally at 65 degrees C and pH 6.5 on a wide range of carbon substrates including cellobiose, hydrocarbons and lactate. In addition to O(2), GE-7 also utilizes nitrate as an electron acceptor. GE-7 is a long rod-shaped bacterium (4-6microm longx0.5microm wide) with terminal endospores and flagella. Phylogenetic analysis of GE-7 16S rDNA sequence revealed high sequence similarity with G. thermoleovorans DSM 5366(T) (99.6%), however, certain phenotypic characteristics of GE-7 were distinct from this and other previously described strains of G. thermoleovorans.

Bacillaceae↗
PubMed2004

Distribution and molecular investigation of highly thermophilic bacteria associated with cool soil environments.

In this study, both molecular and culture-based methods were used to characterize thermophilic bacteria associated with the subsurface soil environment in Northern Ireland. A total of 53 thermophilic, aerobic, sporulating and non-sporulating bacteria were isolated from subsurface soil samples obtained from two sites. They were screened by amplified ribosomal DNA restriction analysis prior to 16 S rRNA gene sequencing. The majority of the sequences were associated with Geobacillus thermoleovorans (50%) and Geobacillus caldoxylosilyticus (34.6%). Isolates F10, F20 and Tf exhibited only 93% similarity with Geobacillus toebii strain F70. Hence they may represent a new species of the genus Geobacillus.

Bacillus↗
PubMed2001

A polyphasic taxonomic study of thermophilic bacilli from shallow, marine vents.

Eighty-seven thermophilic, aerobic, spore-forming bacteria were isolated from shallow, marine, thermal vents of the Eolian Islands (Italy) and tested for a broad spectrum of phenotypic characteristics. A numerical taxonomy study was performed on these isolates and 8 thermophilic Bacillus and Geobacillus reference strains by 89 selected features. Results from cluster analysis showed the formation of nine clusters. Most of the isolates (83%) fell into several phenetically well distinguished clusters, loosely related to Geobacillus thermodenitrificans. The remaining isolates grouped together with different reference strains. Eighteen isolates, representative of the different clusters, were selected for subsequent genotypic characterisation, including partial 16S rDNA sequence analysis of 18 strains and almost complete 16S rDNA sequences of 9 strains. Subsequent DNA/DNA reassociation studies and determination of the base composition of DNA identified seven isolates as Geobacillus thermodenitrificans, two isolates as G. thermoleovorans and one isolate as Bacillus pallidus. Four isolates represented two novel species of Bacillus. The remaining four represented novel Geobacillus species, one of which has recently been described as Bacillus vulcani DSMZ 13174 T.

Bacillus↗
PubMed2006

Two novel bacteriophages of thermophilic bacteria isolated from deep-sea hydrothermal fields.

Bacteriophages of thermophiles are of great interest due to their important roles in many biogeochemical and ecological processes. However, no virion has been isolated from deep-sea thermophilic bacteria to date. In this investigation, two lytic bacteriophages (termed Bacillus virus W1 and Geobacillus virus E1) of thermophilic bacteria were purified from deep-sea hydrothermal fields in the Pacific for the first time. Bacillus virus W1 (BVW1) obtained from Bacillus sp. w13, had a long tail (300nm in length and 15 nm in width) and a hexagonal head (70 nm in diameter). Another virus, Geobacillus virus E1 (GVE1) from Geobacillus sp. E26323, was a typical Siphoviridae phage with a hexagonal head (130 nm in diameter) and a tail (180 nm in length and 30 nm in width). The two phages contained double-stranded genomic DNAs. The genomic DNA sizes of BVW1 and GVE1 were estimated to be about 18 and 41 kb, respectively. Based on SDS-PAGE of purified virions, six major proteins were revealed for each of the two phages. The findings in our study will be very helpful to realize the effect of virus on thermophiles as well as the communities in deep-sea hydrothermal fields.

Bacillaceae↗
PubMed2002

Characterization of Symbiobacterium toebii, an obligate commensal thermophile isolated from compost.

A symbiotic thermophilic bacterium, strain SC-1, was isolated from hay compost (toebi) in Korea. The new isolate exhibited an obligate commensal interaction with a thermophilic Geobacillus strain and required crude extracts and/or culture supernatant from Geobacillus sp. SK-1 for axenic growth. The growth factors from Geobacillus sp. SK-1 were irreversibly inactivated by phenol or protease treatment, suggesting that they might be proteins. The cells of strain SC-1 were non-spore forming, nonmotile rods that were stained Gram-negatively. The isolate was a microaerophilic heterotroph. Growth was observed between 45 degrees and 70 degrees C (optimum: 60 degrees C; 2.4-h doubling time) and pH 6.0 and 9.0 (optimum: pH 7.5). The G+C content of the genomic DNA was 65 mol%, and the major quinones were MK-6 and MK-7. A phylogenetic analysis of its 16S rDNA sequence indicated that strain SC-1 is closely related to Symbiobacterium thermophilum and so was named Symbiobacterium toebii on the basis of its physiological and molecular properties.

Actinobacteria↗
PubMedDate not supplied

[The phylogenetic diversity of aerobic organotrophic bacteria from the Dagan high-temperature oil field].

The distribution and species diversity of aerobic organotrophic bacteria in the Dagan high-temperature oil field (China), which is exploited via flooding, have been studied. Twenty-two strains of the most characteristic thermophilic and mesophilic aerobic organotrophic bacteria have been isolated from the oil stratum. It has been found that, in a laboratory, the mesophilic and thermophilic isolates grow in the temperature, pH, and salinity ranges characteristic of the injection well near-bottom zones or of the oil stratum, respectively, and assimilate a wide range of hydrocarbons, fatty acids, lower alcohols, and crude oil, thus exhibiting adaptation to the environment. Using comparative phylogenetic 16S rRNA analysis, the taxonomic affiliation of the isolates has been established. The aerobic microbial community includes gram-positive bacteria with a high and low G+C content of DNA, and gamma and beta subclasses of Proteobacteria. The thermophilic bacteria belong to the genera Geobacillus and Thermoactinomyces, and the mesophilic strains belong to the genera Bacillus, Micrococcus, Cellulomonas, Pseudomonas, and Acinetobacter. The microbial community of the oil stratum is dominated by known species of the genus Geobacillus (G. subterraneus, G. stearothermophilus, and G. thermoglucosidasius) and a novel species "Geobacillus jurassicus." A number of novel thermophilic oil-oxidizing bacilli have been isolated.

Bacteria, Aerobic↗