排序方式: 共有80条查询结果,搜索用时 10 毫秒
71.
Comparative transcriptome analysis of nodules of two Mesorhizobium–chickpea associations with differential symbiotic efficiency under phosphate deficiency 下载免费PDF全文
72.
73.
74.
Atmane N Dairou J Flatters D Martins M Pluvinage B Derreumaux P Dupret JM Rodrigues-Lima F 《Biochemical and biophysical research communications》2007,361(1):256-262
The arylamine N-acetyltransferases are important xenobiotic-metabolizing enzymes that catalyze an acetyl group transfer from acetylCoA to arylamine substrates. NAT enzymes possess an active-site loop (the active-site P-loop) involved in substrate binding and selectivity. The Gly/Ala residue present at the start of the active-site P-loop, although conserved in all NAT enzymes, is not involved in the catalytic mechanism or substrate binding. Here we show that a small amino acid (such as Gly or Ala) at this position is important not only for maintaining the functions of the active-site P-loop but, more surprisingly, also important for maintaining the overall structural integrity of NAT enzymes. Our data thus suggest that in addition to its role in substrate binding and selectivity, the active-site P-loop could play a wider structural role in NAT enzymes. 相似文献
75.
Huijuan Cao Menghua Yang Huiming Zheng Jiang Zhang Zengtao Zhong Jun Zhu 《Archives of microbiology》2009,191(3):283-289
LuxR/LuxI-type quorum-sensing systems have been shown to be important for symbiotic interactions between a number of rhizobium
species and host legumes. In this study, we found that different isolates of Mesorhizobium tianshanense, a moderately-growing Rhizobium that forms nodules on a number of types of licorice plants, produces several different N-acyl homoserine lactone-like molecules. In M. tianshanense CCBAU060A, we performed a genetic screen and identified a network of regulatory components including a set of LuxI/LuxR-family
regulators as well as a MarR-family regulator that is required for quorum-sensing regulation. Furthermore, compared with the
wild-type strains, quorum-sensing deficient mutants showed a reduced growth rate and were defective in nodule formation on
their host plant Glycyrrhiza uralensis. These data suggest that different M. tianshanense strains may use diverse quorum-sensing systems to regulate symbiotic process.
H. Cao, M. Yang, and H. Zheng contributed equally to this work. 相似文献
76.
Mª José Lorite Javier Donate-Correa Marcelino del Arco-Aguilar Ricardo Pérez Galdona Juan Sanjuán Milagros León-Barrios 《Systematic and applied microbiology》2010
Genetic and symbiotic characterization of 34 isolates from several Lotus species endemic to the Canary Islands showed extraordinary diversity, with bacteria belonging to different species of the genera Mesorhizobium (17 isolates), Sinorhizobium (12 isolates) and Rhizobium/Agrobacterium (5 isolates). In a previous report, we showed that the Sinorhizobium isolates mostly belonged to S. meliloti. Here, we focused on the remaining isolates. The Lotus mesorhizobial strains were distributed in the rrs tree within six poorly resolved branches. Partial sequences from atpD and recA genes produced much better resolved phylogenies that were, with some exceptions, congruent with the ribosomal phylogeny. Thus, up to six different mesorhizobial species were detected, which matched with or were sister species of M. ciceri, M. alhagi, M. plurifarium or M. caraganae, and two represented new lineages that did not correspond to any of the currently recognized species. Neither M. loti nor Bradyrhizobium sp. (Lotus), recognized as the typical Lotus-symbionts, were identified among the Canarian Lotus isolates, although their nodulation genes were closely related to M. loti. However, several subbranches of mesorhizobia nodulating Lotus spp. could be differentiated in a nodC tree, with the isolates from the islands distributed in two of them (A1 and A3). Subbranch A1 included reference strains of M. loti and a group of isolates with a host range compatible with biovar loti, whereas A3 represented a more divergent exclusive subbranch of isolates with a host range almost restricted to endemic Lotus and it could represent a new biovar among the Lotus rhizobia. 相似文献
77.
【目的】本文旨在构建紫云英酵母双杂交AD-cDNA文库和互作靶蛋白筛选平台,为深入研究共生固氮作用的分子机理奠定工作基础。【方法】以接种华癸中慢生根瘤菌7653R的豆科植物紫云英不同时期根部组织为材料,抽提和纯化RNA,构建了一个酵母AD-cDNA文库。库容量达到1.02×106/3μg pGADT7-RecDNA,插入片段大小1-1.5 kb左右。以紫云英豆血红蛋白基因AsB2510构建诱饵载体pGBKT7-AsB2510,利用酵母双杂交技术,筛选与诱饵蛋白相互作用的靶蛋白。【结果】在含有X-gal的SD四缺培养基上筛选得到26个克隆,经过质粒抽提、PCR鉴定、回转酵母验证获得10个阳性克隆。【结论】对阳性克隆的外源片段进行了测序和同源性分析,发现一个值得深入研究的含有tify domain和Divergent CCT motif的转录调控因子。 相似文献
78.
摘要:【目的】repC为质粒复制必需的起始蛋白基因。本研究旨在对华癸中生根瘤菌菌株HN3015及其质粒消除突变株进行repC基因的克隆和鉴定。【方法】采用通用引物RC1和RC3进行repC基因的PCR扩增,扩增产物克隆到载体pMD-18T,然后测序。利用Southern 杂交对repC基因定位。利用在线软件分析基因的序列特征,BLAST 工具进行同源性搜索;ExPASy推断其氨基酸的序列;ClustalW进行同源核苷酸和氨基酸序列的多重比较分析;PredictProtein 进行蛋白二级结构分析。【结果】 相似文献
79.
80.