微体古生物学报最新文献

Medium optimization for nitrogen fixer Paenibacillus sp. 1-49. 固氮剂Paenibacillus sp. 1-49培养基优化。

微体古生物学报 Pub Date : 2016-09-01 DOI: 10.13343/J.CNKI.WSXB.20150538

Zhiping Deng, Hao Chen, San-feng Chen

引用次数: 0

Comparative genomic and protein sequence analyses of the chemotaxis system of Azorhizobium caulinodans. 氮根根瘤菌趋化系统的比较基因组和蛋白质序列分析。

微体古生物学报 Pub Date : 2016-08-04 DOI: 10.13343/J.CNKI.WSXB.20150500

Nanping Jiang, Wei Liu, Yan Li, Zhihong Xie

{"title":"Comparative genomic and protein sequence analyses of the chemotaxis system of Azorhizobium caulinodans.","authors":"Nanping Jiang, Wei Liu, Yan Li, Zhihong Xie","doi":"10.13343/J.CNKI.WSXB.20150500","DOIUrl":"https://doi.org/10.13343/J.CNKI.WSXB.20150500","url":null,"abstract":"Objective\u0000Azorhizobium caulinodans ORS571 can fix nitrogen not only as a free-living organism and an associative-symbiotic bacterium by colonizing the root surface of non-leguminous plants, but also as a symbiotic bacterium by interacting with leguminous plant Sesbania rostrata. Due to its ability to grow and fix nitrogen under three conditions, A. caulinodans uses sophisticated chemotaxis signal transduction systems to transform environmental cues into corresponding behavioral responses. Chemotaxis appears crucial for the growth of A. caulinodansin complicated environment and the construction of associative relationship with the plant. However, little is known about the chemotactic pathway of A. caulinodans. Thus, our study aimed to compare the chemotaxis-like genes of A. caulinodans with those of well-studied species.\u0000\u0000\u0000Methods\u0000NCBI protein BLAST was used for searching sequence similarity with default parameter values against the genomes of A. caulinodans. HMMER3, based on Pfam database, was used for comparative analyses of methyl-accepting chemotaxis protein (MCP).\u0000\u0000\u0000Results\u0000There was a major chemotaxis cluster in A. caulinodans and the CheR methylated MCPs independently of pentapeptide motif. There were 43 MCP homologs containing diverse signal-sensing architectures in A. caulinodans. In addition, cytoplasmic domains of these MCPs were all composed of 38 heptad repeats.\u0000\u0000\u0000Conclusion\u0000Despite the extremely high homology presented between the chemotactic system of A. caulinodans and those of well-studied species, A. caulinodans shows its own unique characteristics. The classification of these chemotactic pathways by comparative genomics enables us to better understand how A. caulinodansresponds to changes in environment via exquisite signal transductions in chemotaxis system.","PeriodicalId":67785,"journal":{"name":"微体古生物学报","volume":"12 1","pages":"1256-65"},"PeriodicalIF":0.0,"publicationDate":"2016-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80465511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Characterization of an exo-chitinase from a Citrobacter strain isolated from the intestine content of large yellow croakers. 从大黄鱼肠内容物中分离的柠檬酸杆菌菌株的外几丁质酶的鉴定。

微体古生物学报 Pub Date : 2016-07-04 DOI: 10.13343/J.CNKI.WSXB.20150410

Jie Xu, Yalin Yang, Yang Liu, Chao Ran, Juan Li, Suxu He, Li Xu, Xhunxiang Ai, Zhigang Zhou

{"title":"Characterization of an exo-chitinase from a Citrobacter strain isolated from the intestine content of large yellow croakers.","authors":"Jie Xu, Yalin Yang, Yang Liu, Chao Ran, Juan Li, Suxu He, Li Xu, Xhunxiang Ai, Zhigang Zhou","doi":"10.13343/J.CNKI.WSXB.20150410","DOIUrl":"https://doi.org/10.13343/J.CNKI.WSXB.20150410","url":null,"abstract":"Objective\u0000We isolated bacterial strains with chitin-degrading activity from the digesta of large yellow croakers (Pseudosciaena crocea) fed with chitin-enriched trash fish, and characterized potential chitinases thereof.\u0000\u0000\u0000Methods\u0000Chitin-degrading strains were screened with colloidal chitin agar from the digesta of P. crocea fed with trash fish. The chitinase gene (chi-X) was cloned and expressed in Escherichia coli, and the enzymatic properties of the chitinase (CHI-X) were characterized.\u0000\u0000\u0000Results\u0000A Citrobacter freundii strain with chitin-degrading activity was isolated. The chitinase gene encodes a protein containing 493 amino acid residues, with a proposed glycoside hydrolase family-18 catalytic domain. CHI-X could hydrolyze colloidal chitin. The optimal pH for CHI-X was 4.0 at optimal temperature (60 ℃). CHI-X was active over a broad pH range, with around 90% of the activity maintained after incubation at pH between 3.0 and 11 for 1 h. The enzymatic activity of CHI-X was stimulated by Mn2+, Li+, and K+, but inhibited by Ag+. The enzyme was stable after treatment by proteases and grouper intestinal juice. CHI-X hydrolyzes colloidal chitin into GlcNAc and (GlcNAc)2. Furthermore, an synergic effect was observed between CHIX and ChiB565 (a chitinase from Aeromonas veronii B565) on colloidal chitin.\u0000\u0000\u0000Conclusion\u0000CHI-X from intestinal bacterium may be potentially used as feed additive enzyme for warm water marine fish.","PeriodicalId":67785,"journal":{"name":"微体古生物学报","volume":"123 1","pages":"1089-1104"},"PeriodicalIF":0.0,"publicationDate":"2016-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78176402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

[Real time PCR quantification of ammonia-oxidizing bacteria in aerobic granular sludge and activated sludge influenced by pentachlorophenol]. [五氯酚对好氧颗粒污泥和活性污泥中氨氧化细菌的实时PCR定量分析]。

微体古生物学报 Pub Date : 2009-05-14 DOI: 10.1504/IJEP.2009.025129

Guang-wei Li, He Liu, Feng Zhang, G. Du, Jian Chen

{"title":"[Real time PCR quantification of ammonia-oxidizing bacteria in aerobic granular sludge and activated sludge influenced by pentachlorophenol].","authors":"Guang-wei Li, He Liu, Feng Zhang, G. Du, Jian Chen","doi":"10.1504/IJEP.2009.025129","DOIUrl":"https://doi.org/10.1504/IJEP.2009.025129","url":null,"abstract":"The V2 region of the 16S ribosomal DNA of the ammonia-oxidizing bacteria (AOB) was amplified directly from the environmental sample by using the specific PCR primers. The purified PCR product was cloned into T-vector and was identified as 16S rDNA fragment of AOB by sequencing and Real-time PCR method. Then, the recombined plasmid was used as standard molecule sample in Real-time PCR for AOB quantification. The numbers of the AOB were monitored in samples of both aerobic granular sludge and activated sludge influenced by PCP by using Real-time PCR. The results showed that the numbers of AOB in aerobic granular sludge and activated sludge were 4.28 x 10(7) 5.44 x 10(6) cells/g dried sludge and 2.51 x 10(9) +/- 8.61 x 10(8) cells/g dried sludge without PCP in the reactors, respectively. With the increase of PCP concentration (from 0mg/L to 50mg/L), the numbers of AOB in both types of sludge had no obvious change( P > 0.05) . The numbers of AOB had no obvious correlation with ammonia removal ( P > 0.05) . The main effect of PCP on AOB in both types of sludge was to inhibit their metabolic activity.","PeriodicalId":67785,"journal":{"name":"微体古生物学报","volume":"448 1","pages":"136-40"},"PeriodicalIF":0.0,"publicationDate":"2009-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82933869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

[Inhibition of IFN-gamma receptor signaling by hepatitis C virus non-structural protein NS4B]. [丙型肝炎病毒非结构蛋白NS4B对ifn - γ受体信号的抑制作用]。

微体古生物学报 Pub Date : 2006-10-01 DOI: 10.3760/CMA.J.ISSN.1008-1372.2008.11.010

Yi Zheng, Hai-bo Luo, B. Gao, Laiqiang Huang

引用次数: 0