• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.177-183
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• 2007

Using complementation of RpoH deficient E. coli strain A7448, the rpoH gene encoding heat shock sigma factor 32 (${\sigma}^{32}$) from Methylovorus sp. strain SS1 DSM11726 was cloned and sequenced. Sequence analysis of a stretch of 1,796-bp revealed existence of an open reading frame encoding a polypeptide of 284 amino acid (32,006 dalton). Deduced amino acid sequence of the Methylovorus sp. strain SS1 RpoH showed that 59.6%, 39.1% and 51.4% identities with those of Nitrosomonas europaea (${\beta}$-proteobacteria), Agrobacterium tumefaciens ($\alpha$-proteobacteria) and E. coli (${\gamma}$-proteobacteria). The expression level of the functional ortholog of RpoH of Methylovorus sp. strain SS1 was increased transiently after heat induction, further indicating that it functions as a heat shock sigma factor.

• Molecules and Cells
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• v.20 no.3
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• pp.392-400
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• 2005

The genes encoding the DNA gyrase A (GyrA) and B subunits (GyrB) of Methylovorus sp. strain SS1 were cloned and sequenced. gyrA and gyrB coded for proteins of 846 and 799 amino acids with calculated molecular weights of 94,328 and 88,714, respectively, and complemented Escherichia coli gyrA and gyrB temperature sensitive (ts) mutants. To analyze the role of type II topoisomerases in the intrinsic quinolone resistance of methylotrophic bacteria, the sequences of the quinolone resistance-determining regions (QRDRs) in the A subunit of DNA gyrase and the C subunit (ParC) of topoisomerase IV (Topo IV) of Methylovorus sp. strain SS1, Methylobacterium extorquens AM1 NCIB 9133, Methylobacillus sp, strain SK1 DSM 8269, and Methylophilus methylotrophus NCIB 10515 were determined. The deduced amino acid sequences of the QRDRs of the ParCs in the four methylotrophic bacteria were identical to that of E. coli ParC. The sequences of the QRDR in GyrA were also identical to those in E. coli GyrA except for the amino acids at positions 83, 87, or 95. The $Ser^{83}$ to Thr substitution in Methylovorus sp. strain SS1, and the $Ser^{83}$ to Leu and $Asp^{87}$ to Asn substitutions in the three other methylotrophs, agreed well with the minimal inhibitory concentrations of quinolones in the four bacteria, suggesting that these residues play a role in the intrinsic susceptibility of methylotrophic bacteria to quinolones.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.179-183
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• 1993

A restricted facultatively methanol-oxidizing bacterium, Methylovorus sp. strain SS1, was isolate dfrom soil samples from Kuala Lumpur, Malaysia, through methanol-enrichment culture technique. The isolate was nonmotile Gram-negative rod and did not have complex internal membrane system. The colonies were small, pale-yellow, and raised convex with entire margin. The cell did not produce any spores and capsular materials. The cell was obligately aerobic and exhibited catalase, but no oxidase, activity. Plasmid, carotenoid pigment, and poly-.betha.-hydroxybutyric acid were not found. The guanine plus cytosine content of the DNA was 55%. The isolate was found to grow only on methanol methylamine, or glucose. Growth factors were not required. Cells growing on methanol was found to produce extracellular polysaccharides containing glucose, lactose, and fructose. Growth was optimal (t$_{d}$= 1.7) with 0.5%(v/v) methanol at 40.deg.C and pH 6.5. No Growth was observed at over 60.deg.C. Cell-free extracts of the methanol grown cells exhibited the phenazine methosulfate-linked methanol dehydrogenase activity Methanol was found to be assimilate dthrough the ribulose monophosphate pathway.y.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.207-211
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• 1998

Melhylovorus sp. strain SS1 grown on methanol was found to show activities of key enzymes of the linear route, $NAD^+$-linked formaldehyde and formate dehydrogenases, and the cyclic route, hexulose-6-phosphate synthase, glucose-6-phosphate isomerase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase, for formaldehyde oxidation. The activities of the cyclic route enzymes were higher than those of the linear route enzymes. The bacterium also exhibited activities of the key enzymes of the ribulose monophosphate and Entner-Doudoroff pathways and transaldolase involved in the formaldehyde assimilation and the enzymes involved in the biosynthesis of extracellular polysaccharide. Cells grown in the presence of 2.3 mM ammonium sulfate were higher in the productivity of extracellular polysaccharide, but lower in the growth yield, than those grown in the presence 7.6 mM ammonium sulfate. The activities of 6-phosphogluconate dehydrogenase, phosphoglucomutase, and UDP-pyrophosphorylase in cells grown under nitrogen-limited condition were higher, but that of 6-phosphogluconate dehydratase/2-keto-3-deoxy-6-phosphogluconate aldolase was lower, than those in cells grown in the presence of sufficient amount of nitrogen source.

• BMB Reports
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• v.38 no.6
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• pp.695-702
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• 2005

The groESL bicistronic operon of a restricted facultative methylotrophic bacterium Methylovorus sp. strain SS1 DSM 11726 was cloned and characterized. It was found to consist of two ORFs encoding proteins with molecular masses of 11,395 and 57,396 daltons, which showed a high degree of homology to other bacterial GroES and GroEL proteins. The genes were clustered in the transcription order groES-groEL. Northern blot analyses suggested that the groESL operon is transcribed as a bicistronic 2.2-kb mRNA, the steady-state level of which was markedly increased by temperature elevation. Primer extension analysis demonstrated one potential transcription start site preceding the groESL operon, which is located 100bp upstream of the groES start codon. The transcription start site was preceded by a putative promoter region highly homologous to the consensus sequences of Escherichia coli ${\sigma}^{32}$-type heat shock promoter, which functioned under both normal and heat shock conditions in E. coli. Heat shock mRNA was maximally produced by Methylovorus sp. strain SS1 approximately 10min after increasing the temperature from 30 to $42^{\circ}C$. The groESL operon was also induced by hydrogen peroxide or salt shock.

• Journal of Microbiology
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• v.39 no.3
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• pp.162-167
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• 2001

Methylovorus sp. strain SS1 DSM 11726 was found to grow continuously when it was transferred from 30$\^{C}$ to 40$\^{C}$ and 43$\^{C}$. A shift in growth temperature from 30$\^{C}$ to 45$\^{C}$, 47$\^{C}$ and 50$\^{C}$ reduced the viability of the cell population by more than 10$^2$, 10$^3$and 10$\^$5/ folds, respectively, after 1h cultivation. Cells transferred to 47$\^{C}$ and 50$\^{C}$ after preincubation for 15 min at 43$\^{C}$, however, exhibited 10-fold increase in viability. It was found that incubation for 15 min at 40$\^{C}$ of Methylovorus sp. strain SSl grown at 30$\^{C}$ was sufficient to accelerate the synthesis of a specific subset of proteins. The major heat shock proteins had apparent molecular masses of 90, 70, 66, 60, and 58 kDA. The 60 and 58 kDa proteins were found to cross-react with the antiserum raised against GroEL protein. The heat shock response persisted for over 1h. The shock proteins were stable for 90 min in the cell. Exposure of the cells to methanol induced proteins identical to the heat shock proteins. Addition of ethanol induced a unique protein with a molecular mass of about 40 kDa in addition to the heat-induced proteins. The proteins induced in paraquat-treated cells were different from the heat shock proteins, except the 70 and 60 kDa proteins.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.308.2-308
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• 1998

• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.224.2-224
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• 1994

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.252.2-252
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• 1997

• Korean Journal of Microbiology
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• v.33 no.2
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• pp.142-148
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• 1997

Mrthylov~orits sp. starin SSl, a restricted facultative methylotrophic bacterium. growing on methanol was found to produce small amount of extracellular polysaccharide (EPS) under the optimal growth conditions, while it produced large amount of the polysaccharide under nitrogen limihtion. The optimal ratio of carbon to nitrogen for EPS production were found to be 5.2. The optimal temperature and pH for EPS production were 30^{\circ}C.$ and 6.5, spectively. The EPS consisted of carbohydrate, protein and small amount pyruvic acid. The reducing sugars in the EPS consisted mainly of glucose and a small amount of mannose. The EP!; treated with ethanol (EPSae) was found to have several properties different from those of the EPS which was not treated with ethanol (EPSbe); the EPSae contained no pyruvic acid. It also contained less protein and showed much lower viscosity than the EPSbe. The viscosity of EPSbe was very sensitive to NaCl and decreased t;harply upon exposure of the polysaccharide to even 0.5% (wiv) NaCl solution. The viscosity, however, was increased irreversibly upon exposure of the saccharide to high temperature. The molecular weight of EPS was estimiited to be $2.5{\times}$10^6$ - $3.5{\times}*$10^6$ using Sepharose hB column chromatography. Scanning electron microscopy revealed that the lyophilized EPSbe and EPSae have a structure of thread-like fibers and a mesh-like structure resembling bee-hive, respectively.