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Isolation and characterization of glacier VMY22, a novel lytic cold-active bacteriophage of Bacillus cereus 被引量:6
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作者 Xiuling Ji Chunjing Zhang +4 位作者 Yuan Fang Qi Zhang Lianbing Lin Bing Tang Yunlin Wei 《Virologica Sinica》 SCIE CAS CSCD 2015年第1期52-58,共7页
As a unique ecological system with low temperature and low nutrient levels, glaciers are considered a "living fossil" for the research of evolution. In this work, a lytic cold-active bacteriophage designated... As a unique ecological system with low temperature and low nutrient levels, glaciers are considered a "living fossil" for the research of evolution. In this work, a lytic cold-active bacteriophage designated VMY22 against Bacillus cereus MYB41-22 was isolated from Mingyong Glacier in China, and its characteristics were studied. Electron microscopy revealed that VMY22 has an icosahedral head(59.2 nm in length, 31.9 nm in width) and a tail(43.2 nm in length). Bacteriophage VMY22 was classified as a Podoviridae with an approximate genome size of 18 to 20 kb. A one-step growth curve revealed that the latent and the burst periods were 70 and 70 min, respectively, with an average burst size of 78 bacteriophage particles per infected cell. The pH and thermal stability of bacteriophage VMY22 were also investigated. The maximum stability of the bacteriophage was observed to be at pH 8.0 and it was comparatively stable at p H 5.0–9.0. As VMY22 is a cold-active bacteriophage with low production temperature, its characterization and the relationship between MYB41-22 and Bacillus cereus bacteriophage deserve further study. 展开更多
关键词 Bacillus CEREUS characterization cold-active PHAGE LYTIC Podoviridae
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Cloning and heterologous expression of pro-2127,a gene encoding cold-active protease from Pseudoalteromonas sp.QI-1 被引量:1
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作者 XU GuoYing CUI ShuoShuo LIN XueZheng 《Advances in Polar Science》 2011年第2期124-130,共7页
The psychrotropic bacterium, Pseudoalteromonas sp. QI-I, which produces extracellular cold-active protease, was isolated from Antarctic seawater. The genomic DNA of this bacterium was used to construct a plasmid genom... The psychrotropic bacterium, Pseudoalteromonas sp. QI-I, which produces extracellular cold-active protease, was isolated from Antarctic seawater. The genomic DNA of this bacterium was used to construct a plasmid genomic library with the goal of screening cold-active protease genes. Gene pro-2127 with an open reading frame of 2127 bp encoding protease PRO-2127 was cloned and sequenced. Alignment of amino acid sequences suggested that the precursor of PRO-2127 was a member of subfamily S8A, and that it might contain four domains: a signal peptide, an N-terminal prosequence, a catalytic domain and a C-terminal extension. Amino acids Asp185, His244 and Ser425 might form a catalytic triad. PRO-2127 showed some structural features common to psychrophilic enzymes, such as a decrease in Arg residues and the Arg/(Arg+Lys) ratio. Heterologous expression of pro-2127 in Escherichia coli BL21 (DE3) by pColdlII was also successfully observed in this study. 展开更多
关键词 ANTARCTIC PSEUDOALTEROMONAS cold-active protease gene cloning and expression
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Purification and characterization of cold-active endo-1,4-β-glucanase produced by Pseudoalteromonas sp. AN545 from Antarctica
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作者 沈继红 阚光锋 +3 位作者 史翠娟 雷振环 解秋菊 钱文佳 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2011年第5期1086-1092,共7页
A bacterium hydrolyzing carboxymethylcellulose, isolated from Antarctic sea ice, was identified as Pseudoalteromonas sp. based on 16S rDNA gene sequences and named as Pseudoalteromonas sp. AN545. The extracellular end... A bacterium hydrolyzing carboxymethylcellulose, isolated from Antarctic sea ice, was identified as Pseudoalteromonas sp. based on 16S rDNA gene sequences and named as Pseudoalteromonas sp. AN545. The extracellular endo-1,4-β-glucanase AN-1 was purified successively by ammonium sulfate precipitation, DEAE-Sepharose ion exchange chromatography and Sephadex G-75 gel filtration chromatography. The molecular mass of AN-1 was estimated to be 47.5 kDa utilizing SDS-PAGE and gel chromatography analysis. AN-1 could hydrolyze caboxymethylcellulose, avicel and β-glucan, but not cellobiose, xylan and p-Nitrophenyl-β-D-glucopyranoside. The optimal temperature and pH for the β-glucanase activity of AN-1 were determined to be at 30℃ and pH 6.0, respectively. AN-1 was stable at acidic solutions of pH 5.0-6.5 and temperatures below 30℃ for 1 h. Moreover, the specific activity was enhanced by Ca2+ and Mg2., and inhibited by Cu2+. The kinetic parameters Michaelis constant (Km) and maximum velocity (Vmax) of AN-1 were 3.96 mg/mL and 6.06×10-2 mg/(min.mL), respectively. 展开更多
关键词 PSEUDOALTEROMONAS endo-l 4-β-glucanase cold-active enzyme Antarctic sea ice stability
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Purification and Characterization of Cold-active α-Amylase Excreted by A Strain of Marine Cold-adaptive Penicillia
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作者 WANGTian-hong ZHANGGang HOUYun-hua 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2004年第1期60-64,共5页
The filamentous fungi from the Huanghai sea sludge were screened according to their ability to produce cold-active α-amylase. The strain with the highest amylase activity was identified as Penicillium species. The ... The filamentous fungi from the Huanghai sea sludge were screened according to their ability to produce cold-active α-amylase. The strain with the highest amylase activity was identified as Penicillium species. The α-amylase purified by ammonium sulphate precipitation and column chromatography on DEAE-sepharose and sephadex G-100 shows a molecular weight of about 55000 and a pI of 4.38. The enzyme is stable in a pH range of 5.5—8.0 and has a maximum activity at pH 6.0. Compared with the α-amylase from mesophiles and thermophiles, the cold-active enzyme shows a high enzyme activity at lower temperatures and a high sensitivity at temperatures higher than 50 ℃. The optimal temperature is 40 ℃ and the activity decreases dramatically at temperatures above 50 ℃. Ca 2+ shows a significant effect on maintaining the structure and the activity of the enzyme. EDTA and Cu 2+ are its inhibitors. The products from the hydrolysis of soluble starch with the cold-active enzyme are maltose and other oligosaccharides. 展开更多
关键词 cold-active α-amylase Marine Penicillium PURIFICATION Characterization
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Molecular Cloning and Characterization of a New Cold-active Extradiol Dioxygenase from a Metagenomic Library Derived from Polychlorinated Biphenyl-contaminated Soil
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作者 REN He-jun LU Yang +3 位作者 ZHOU Rui DAI Chun-yan WANG Yah ZHANG Lan-ying 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2012年第4期666-671,共6页
To find new extradiol dioxygenases(EDOs,EC 1.13.11.2),a metagenomics library was constructed from polychlorinated biphenyl-contaminated soil and was screened for some dioxygenase with aromatic ring cleavage activity... To find new extradiol dioxygenases(EDOs,EC 1.13.11.2),a metagenomics library was constructed from polychlorinated biphenyl-contaminated soil and was screened for some dioxygenase with aromatic ring cleavage activity.A novel EDO,designated as BphC_A,was identified and heterologously expressed in Escherichia coli.The deduced amino acid sequence of BphC_A exhibited a homology of less than 60% with other known EDOs.Phylogenetic analysis of BphC_A suggests that the protein is a novel member of the EDO family.The enzyme exhibits higher substrate affinity and catalytic efficiency toward 3-methylcatechol than toward 2,3-dihydroxybiphenyl or catechol,the preferred substrate of other known EDOs.The optimum activity of purified BphC_A occurred at pH=8.5 and 35 °C,and BphC_A showed more than 40% of its initial activity at 5 °C.The activity of purified BphC_A was significantly induced by Mn^2+ and slightly reduced by Al^3+,Cu^2+ and Zn^2+. 展开更多
关键词 Extradiol dioxygenase METAGENOME cold-active enzyme Gene cloning Functional characterization
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Characterizing proteases in an Antarctic Janthinobacterium sp. isolate: Evidence of a protease horizontal gene transfer event
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作者 Cecilia Martinez-Rosales Juan José Marizcurrena +3 位作者 Andrés Iriarte Natalia Fullana Héctor Musto Susana Castro-Sowinski 《Advances in Polar Science》 2015年第1期88-95,共8页
We report the isolation of a cold-adapted bacterium belonging to the genus Janthinobacterium (named AU 11), from a water sample collected in Lake Uruguay (King George Island, South Shetlands). AUI 1 (growth betwe... We report the isolation of a cold-adapted bacterium belonging to the genus Janthinobacterium (named AU 11), from a water sample collected in Lake Uruguay (King George Island, South Shetlands). AUI 1 (growth between 4℃ and 30℃) produces a single cold-active extracellular protease (ExPAU11), differentially expressed at low temperature. ExPAU11 was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS) as an alkaline metallo-protease (70% coverage with an extracellular protease of Janthinobacterium sp. PI12), and by protease-inhibitor screening identified as a serine-protease. To the best of our knowledge this is the first experimental evidence of a cold-active extracellular protease produced by Janthinobacterium. Furthermore, we identified a serine-protease gene (named JSP8A) showing 60% identity (98% query coverage) to subtilisin peptidases belonging to the $8 family (S8A subfamily) of many cyanobacteria. A phylogenetic analysis of the JSP8A protease, along with related bacterial protein sequences, confirms that JSP8A clusters with S8A subtilisin sequences from different cyanobacteria, and is clearly separated from SSA bacterial sequences of other phyla (including its own). An analysis of the genomic organization around JSP8A suggests that this protease gene was acquired in an event that duplicated a racemase gene involved in transforming L- to D-amino acids. Our results suggest that AU11 probably acquired this subtilisin-like protease gene by horizontal gene transfer (HGT) from a cyanobacterittrn. We discuss the relevance of a bacterial protease-HGT in the Antarctic environment in light of this hypothesis. 展开更多
关键词 ANTARCTIC cold-active protease horizontal gene transfer Janthinobacterium SUBTILISIN
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