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101.
Patompon Wongtrakoongate Apiratana Kum‐arth Pisanu Buphamalai Sumalee Tungpradabkul 《Microbiology and immunology》2013,57(9):605-615
Burkholderia pseudomallei, a pathogenic gram‐negative bacterium, causes the severe human disease melioidosis. This organism can survive in eukaryotic host cells by escaping reactive oxygen species via the regulation of stress responsive sigma factors, including RpoS. In B. pseudomallei, RpoS has been reported to play a role in the oxidative stress response through enhanced activity of OxyR and catalase. In this study, the RpoS dependent oxidative stress responsive system was further characterized using comparative proteomic analysis. The proteomic profiles of wild‐type B. pseudomallei following exposure to H2O2 and between wild‐type and the rpoS mutant strains were analyzed. Using stringent criteria, 13 oxidative responsive proteins, eight of which are regulated by RpoS, were identified with high confidence. It was observed that ScoA, a subunit of the SCOT enzyme not previously shown to be involved directly in the oxidative stress response, is significantly down‐regulated after hydrogen peroxide treatment. ScoA and ScoB have been predicted to be organized in a single operon using computational methods: in this study it was confirmed by RT‐PCR that these genes are indeed co‐transcribed as a single mRNA. The present study is the first to report a role for RpoS in the down‐regulation of SCOT expression in response to oxidative stress in B. pseudomallei. 相似文献
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103.
Richard DJ Savage K Bolderson E Cubeddu L So S Ghita M Chen DJ White MF Richard K Prise KM Schettino G Khanna KK 《Nucleic acids research》2011,39(5):1692-1702
hSSB1 is a newly discovered single-stranded DNA (ssDNA)-binding protein that is essential for efficient DNA double-strand break signalling through ATM. However, the mechanism by which hSSB1 functions to allow efficient signalling is unknown. Here, we show that hSSB1 is recruited rapidly to sites of double-strand DNA breaks (DSBs) in all interphase cells (G1, S and G2) independently of, CtIP, MDC1 and the MRN complex (Rad50, Mre11, NBS1). However expansion of hSSB1 from the DSB site requires the function of MRN. Strikingly, silencing of hSSB1 prevents foci formation as well as recruitment of MRN to sites of DSBs and leads to a subsequent defect in resection of DSBs as evident by defective RPA and ssDNA generation. Our data suggests that hSSB1 functions upstream of MRN to promote its recruitment at DSBs and is required for efficient resection of DSBs. These findings, together with previous work establish essential roles of hSSB1 in controlling ATM activation and activity, and subsequent DSB resection and homologous recombination (HR). 相似文献
104.
A Gram-negative, non-motile, catalase- and oxidase- positive, strictly aerobic, and short rod-shaped bacterium that was designated
strain KOPRI 25157T was isolated from coastal seawater sample in Antarctica. The temperature and pH ranges for growth on R2A agar were 10–20°C,
and 5.0–10.0, respectively. Phylogenetic analyses of the 16S rRNA gene sequence of strain KOPRI 25157T showed it to belong to the family Oxalobacteraceae of the class Betaproteobacteria, and it formed a distinct clade from other recognized members of the family. DNA G + C content was 65.9 mol%. Major ubiquinone
was Q-8. Predominant cellular fatty acids were C16:1
ω7c/15 iso 2OH (56.4%) and C16:1 (30.5%). Major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, and unknown lipid. On the basis of these
data, it is proposed that strain KOPRI 25157T is the representative of a novel genus, for which the name Actimicrobium gen. nov. is proposed in the family Oxalobacteraceae. The type strain for Actimicrobium antarcticum sp. nov. is KOPRI 25157T (=JCM 16673T=KCTC 23040T). 相似文献
105.
Yung Mi Lee GoHeung Kim You-Jung Jung Cheng-Dae Choe Joung Han Yim Hong Kum Lee Soon Gyu Hong 《Polar Biology》2012,35(9):1433-1438
Microorganisms in polar areas may have important ecological roles in biogeochemical cycles and the food chain. They are adapted to polar environments by means of special physiological adaptation mechanisms that include cold-adapted enzymes and cryoprotectants such as exopolysaccharides. Culture collections for polar microorganisms can provide research resources for ecological and physiological studies. The Polar and Alpine Microbial Collection (PAMC) is a specialized culture collection for maintenance and distribution of polar and alpine microorganisms. A database system was developed to share important data fields with DarwinCore2 and Ocean Biogeographic Information System database schemas. Approximately 1,500 out of 5,500 strains maintained in PAMC have been identified and belonged primarily to the phyla Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. Many of the microbial strains can grow at low temperature and produce proteases, lipases, and/or exopolysaccharides. PAMC provides search tools based on keywords such as taxonomy, geographical origin, habitat, and physiological characteristics. Biological materials and information provided by PAMC will be important resources for ecological and physiological studies on polar and alpine microorganisms. 相似文献
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108.
Arsenic is one of the most important water pollutants because of its carcinogenicity. The association between arsenical poisoning and the development of internal malignancies and skin cancer is well known. The U.S. Environmental Protection Agency (USEPA) sets maximum contaminant level goals at zero for carcinogens. In this study are presented groundwater arsenic concentrations in the area of naturally rich boron sources of Turkey. Water samples were collected from the Hisarcik, Turkey, area, which has a large boron mine. An inductively coupled plasma/mass spectrometry method was used to analyze arsenic concentrations in water samples. The arsenic levels in water ranged from no detectable amounts to 3.00 mg As/L (mean: 0.46 ± 0.07SD). This mean As level exceeds by a factor of 10 the USEPA's current Maximum Contaminant Level of 0.05 mgAs/L. Some possible health problems associated with consumption of arsenic-contaminated water are discussed and public health interventions proposed. 相似文献
109.
Seo C Choi YH Sohn JH Ahn JS Yim JH Lee HK Oh H 《Bioorganic & medicinal chemistry letters》2008,18(2):772-775
Ohioensins F and G (1 and 2), two new benzonaphthoxanthenones, have been isolated from the MeOH extract of Antarctic moss Polytrichastrum alpinum by various chromatographic methods. The structures of these compounds were determined mainly by analysis of NMR spectroscopic data. The known compounds ohioensins A and C (3 and 4) were also obtained. Compounds 1-4 showed potent inhibitory activity against therapeutically targeted protein tyrosine phosphatase 1B (PTP1B). Kinetic analysis of PTP1B inhibition by ohioensin F (1) suggested that benzonaphthoxanthenones inhibited PTP1B activity in a non-competitive manner. 相似文献
110.