Methylobacterium radiodurans sp. nov., a novel radiation-resistant Methylobacterium.

A Gram-negative, aerobic, flagellated, rod-shaped, and pink-pigmented bacterium, strain 17Sr1-43 T, was isolated from a soil sample collected in Nowongu, Seoul, Korea. The isolate could grow at 18-37 °C (optimum, 28-30 °C), pH 6.0-8.0 (optimum, pH 7.0) and in the presence of 0-1.0% (w/v) NaCl (optimum, 0%) with aeration. The major cellular fatty acids were summed feature 8 (C18:1 ω7c and/or C18:1 ω6c) and summed feature 2 (iso-C16:1 I and/or C14:0 3-OH). The predominant respiratory quinone was Q-10 and the major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phospholipid, and diphosphatidylglycerol. The G + C content of genomic DNA was 69.1 mol%. Strain 17Sr1-43 T was closely related to Methylobacterium gregans KACC 14808 T (98.4% 16S rRNA gene sequence similarity), Methylobacterium hispanicum KACC 11432 T (97.9%), and Methylobacterium phyllosphaerae CBMB27T (96.1%). The complete genome of strain 17Sr1-43 T contains essential genes related to DNA repair processes including bacterial RecBCD dependent pathway and UmuCD system. Based on the phenotypic, genotypic, and chemotaxonomic characteristics, strain 17Sr1-43 T represents a novel species in the genus Methylobacterium, for which the name Methylobacterium radiodurans sp. nov. is proposed. The type strain is strain 17Sr1-43 T (= KCTC 52906 T = NBRC 112875 T).

Methylobacterium terricola sp. nov., a gamma radiation-resistant bacterium isolated from gamma ray-irradiated soil.

A gamma radiation-resistant and pink-pigmented bacterial strain, designated as 17Sr1-39T, was isolated from a gamma ray-irradiated soil sample collected in the Republic of Korea. Cells were Gram-stain-negative, strictly aerobic, flagellated, asporogenous, rod-shaped and methylotrophic. Results of 16S rRNA gene sequence analysis showed that strain 17Sr1-39T was phylogenetically related to Methylobacterium currus PR1016AT (97.3 %), Methylobacterium aquaticum DSM 16371T (97.2 %), Methylobacterium platani PMB02T (97.0 %), Methylobacterium frigidaeris IER25-16T (96.6 %), Methylobacterium terrae 17Sr1-28T (96.6 %) and Methylobacterium organophilum JCM 2833T (93.4 %). The G+C content calculated based on the genome sequence was 70.4 mol%. The average nucleotide identity and in silico DNA-DNA hybridization values between strain 17Sr1-39T and M. currus, M. aquaticum, M. platani, M. frigidaeris, M. terrae and M. organophilum were 77.3-89.9 and 22-38.2 %, respectively. The predominant fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The predominant quinone was ubiquinone 10 and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Based on the data from phenotypic tests and genotypic differences between strain 17Sr1-39T and its close phylogenetic relatives, strain 17Sr1-39T represented a new species belonging to the genus Methylobacterium, for which the name Methylobacterium terricola sp. nov. (=KACC 52905T=NBRC 112874T) is proposed.

Methylobacterium durans sp. nov., a radiation-resistant bacterium isolated from gamma ray-irradiated soil.

A gamma radiation-resistant, Gram-stain negative, oxidase and catalase positive, aerobic, flagellated, rod-shaped, methylotrophic and pink-pigmented bacterial strain designated 17SD2-17 T was isolated from gamma-ray-irradiated soil collected in Korea. The 16S rRNA gene sequence analysis showed that strain 17SD2-17 T is phylogenetically related to Methylobacterium organophilum DSM 760 T (97.6%), Methylobacterium oxalidis 35aT (97.4%) and Methylobacterium soli YIM 48816 T (97.0%). The G+C content calculated based on the draft genome sequence is 68.7 mol%. The DNA-DNA hybridisation between 17SD2-17 T and its close relatives was found to be less than 40%. The predominant fatty acid was identified as summed feature 8 (C18:1ω7c and/or C18:1ω6c) and the major respiratory quinone as Q-10. The major polar lipids were found to be diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. On the basis of the data from phenotypic tests and genotypic differences between strain 17SD2-17 T and its close phylogenetic relatives, strain 17SD2-17 T is concluded to represent a new species belonging to the genus Methylobacterium, for which the name Methylobacterium durans sp. nov. (= KCTC 52908 T = NBRC 112876 T) is proposed.

Methylobacterium terrae sp. nov., a radiation-resistant bacterium isolated from gamma ray-irradiated soil.

A Gram-stain-negative, asporogenous, aerobic rods, motile by means of a single polar flagellum, catalase- and oxidase-positive, methylotrophic bacterium, designated 17Sr1-28T, was isolated from gamma ray-irradiated soil. The 16S rRNA gene sequence analysis showed that strain 17Sr1-28T was phylogenetically related to Methylobacterium currus PR1016AT (96.8%), Methylobacterium platani PMB02T (96.2%), Methylobacterium aquaticum DSM 16371T (96.3%), Methylobacterium tarhaniae N4211T (96.4%), Methylobacterium frigidaeris IER25-16T (95.8%), and Methylobacterium organophilum JCM 2833T (92.7%). The G+C content calculated based on genome sequence was 71.6%. The average nucleotide identity and in silico DNA-DNA hybridization values between strain 17Sr1- 28T and M. currus, M. platani, M. aquaticum, M. tarhaniae, M. frigidaeris, and M. organophilum were 77.7-90.4% and 22-39.6%, respectively. The major fatty acids of strain 17Sr1-28T were summed feature 8 (C18:1ω7c and/or C18:1ω6c), and summed feature 3 (C16:1ω7c and/or C16:1ω6c). The predominant quinone was ubiquinone 10 and the major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, and phosphatidylglycerol. On the basis of the data from phenotypic tests and genotypic differences between strain 17Sr1-28T and its close phylogenetic relatives, strain 17Sr1-28T represents a new species belonging to the genus Methylobacterium, for which the name Methylobacterium terrae sp. nov. (= KCTC 52904T = NBRC 112873T) is proposed.

Evaluation of Methylobacterium radiotolerance and Sphyngomonas yanoikoaie in Sentinel Lymph Nodes of Breast Cancer Cases.

It has been established that different kinds of bacteria agents are involved in various cancers. Although the mechanism of tumorigenesis is not clearly understood, there is evidence for the presence of bacteria within tumors, with at least a progression effect for some bacteria that prepare suitable microenvironments for tumor cell growth. The aim of current study was to evaluate bacterial dysbiosis in sentinel lymph nodes of breast cancer patients. One hundred and twenty three fresh-frozen sentinel lymph nodes and a corresponding number of normal adjacent breast tissue specimens and five normal mastectomy samples were investigated employing RT-PCR. In addition using genus-specific primers were applied. There was a significant differences as presence of Methylobacterium radiotolerance DNA recorded between patients and normal control group (p= 0.0). Based on our research work, further studies into the role of microbes in breast cancer would be of great interest.

[Effect of DNA-damaging agents on the aerobic methylobacteria capable and incapable of utilizing dichloromethane].

Methylobacterium dichloromethanicum DM4, a degrader of dichloromethane (DCM), was more tolerant to the effect of H2O2 and UV irradiation than Methylobacterium extorquens AM1, which does not consume DCM. Addition of CH2Cl2 to methylobacteria with active serine, ribulose monophosphate, and ribulose bisphosphate pathways of C1 metabolism, grown on methanol, resulted in a 1.1- to 2.5-fold increase in the incorporation of [alpha-32P]dATP into DNA Klenow fragment (exo-). As DCM dehalogenase was not induced in this process, the increase in total lengths of DNA gaps resulted from the action of DCM rather than S-chloromethylglutathione (intermediate of primary dehalogenation). The degree of DNA damage in the presence of CH2Cl2 was lower in DCM degraders than methylobacteria incapable of degrading this pollutant. This suggests that DCM degraders possess a more efficient mechanism of DNA repair.

[The effect of gamma-radiation and desiccation on the viability of the soil bacteria isolated from the alienated zone around the Chernobyl Nuclear Power Plant]. / Vliianie gamma-izlucheniia i degidratatsii na vyzhivaemost' bakterii, izolirovannykh iz zony otchuzhdeniia Chernobyl'skoi AES.

Methylobacterium extorquens, M. mesophilicum, and Bacillus subtilis strains were found to be resistant to gamma-radiation, irrespective of whether they were isolated from the alienated zone around the Chernobyl Nuclear Power Plant or outside this zone. The LD90 of Methylobacterium and B. subtilis strains with respect to gamma-radiation was 2.0-3.4 and 3.7-4.4 kGy, respectively, whereas their LD99.99 values were 4.5-6.9 and more than 10 kGy, respectively. The high threshold levels of gamma-radiation for Methylobacterium and B. subtilis imply the efficient functioning of DNA repair systems in these bacteria. Unlike Bacillus polymyxa cells, the cells of M. extorquens, M. mesophilicum, and B. subtilis were also resistant to desiccation. Pseudomonas sp., Nocardia sp., and nocardioform actinomycetes were sensitive to both gamma-radiation and desiccation. Similar results were obtained when the bacteria studied were exposed to hydrogen peroxide and ultraviolet radiation. The results obtained indicate that the bacteria that are resistant to gamma-radiation are also resistant to desiccation, UV radiation, and hydrogen peroxide. The possibility of using simple laboratory tests (such as the determination of bacterial resistance to UV light and desiccation) for the evaluation of bacterial resistance to gamma-radiation is discussed.