从广东省徐闻盐场沉积物中分离嗜盐菌,鉴定目标菌株、考察培养条件,并对发酵液中抗菌活性物质进行理化性质研究。用稀释涂布法分离嗜盐菌,通过生理生化实验和16S r RNA基因序列分析鉴定分离得到的菌株;采用管碟法考察嗜盐菌发酵液的抗...从广东省徐闻盐场沉积物中分离嗜盐菌,鉴定目标菌株、考察培养条件,并对发酵液中抗菌活性物质进行理化性质研究。用稀释涂布法分离嗜盐菌,通过生理生化实验和16S r RNA基因序列分析鉴定分离得到的菌株;采用管碟法考察嗜盐菌发酵液的抗菌活性,并对其抗菌活性物质进行理化分析。结果显示,分离得到一株嗜盐菌,经生理生化实验和16S r RNA序列分析鉴定后命名为达坂喜盐芽胞杆菌(Halobacillus dabanensis)N522,其最适生长p H值和Na Cl浓度分别为7.0和100 g/L,属于中度嗜盐菌类群。菌株N522的发酵液对多种细菌和真菌具有抑制作用,其中,对金黄色葡萄球菌的抑制能力最强。经硫酸铵盐析和蛋白酶实验分析,初步确定菌株N522所产抗菌活性物质为多肽,分子量在3-5 k D之间,并且该抗菌活性物质对p H和温度稳定性良好。晒盐场沉积物中分离得到的中度嗜盐菌H.dabanensis N522可作为开发抗菌药物的潜在新来源。展开更多
The Na+/H+ antiporter plays key roles in maintaining low cytoplasmic Na+ level and pH homeostasis,while little is known about the Carboxyl-terminal hydrophilic tails of prokaryotic antiporters.In our previous study,th...The Na+/H+ antiporter plays key roles in maintaining low cytoplasmic Na+ level and pH homeostasis,while little is known about the Carboxyl-terminal hydrophilic tails of prokaryotic antiporters.In our previous study,the first Na+/H+ antiporter gene nhaH from moderate halophiles was cloned from Halo-bacillus dabanensis D-8 by functional complementation.A topological model suggested that only nine amino acid residues(395PLIKKLGMI403) existed in the hydrophilic C-terminal domain of NhaH.The C-terminal truncated mutant of NhaH was constructed by PCR strategy and designated as nhaH△C.Salt tolerance experiment demonstrated that the deletion of hydrophilic C-terminal nine amino acid resi-dues significantly inhibited the complementation ability of E.coli KNabc,in which three main Na+/H+ antiporters nhaA,nhaB and chaA were deleted.Everted membrane vesicles prepared from E.coli KNabc/nhaH△C decreased both Na+/H+ and Li+/H+ exchange activities of NhaH,and also resulted in an acidic shift of its pH profile for Na+,indicating a critical role of the short C-terminal domain of NhaH antiporter in alkali cation binding/translocation and pH sensing.展开更多
文摘从广东省徐闻盐场沉积物中分离嗜盐菌,鉴定目标菌株、考察培养条件,并对发酵液中抗菌活性物质进行理化性质研究。用稀释涂布法分离嗜盐菌,通过生理生化实验和16S r RNA基因序列分析鉴定分离得到的菌株;采用管碟法考察嗜盐菌发酵液的抗菌活性,并对其抗菌活性物质进行理化分析。结果显示,分离得到一株嗜盐菌,经生理生化实验和16S r RNA序列分析鉴定后命名为达坂喜盐芽胞杆菌(Halobacillus dabanensis)N522,其最适生长p H值和Na Cl浓度分别为7.0和100 g/L,属于中度嗜盐菌类群。菌株N522的发酵液对多种细菌和真菌具有抑制作用,其中,对金黄色葡萄球菌的抑制能力最强。经硫酸铵盐析和蛋白酶实验分析,初步确定菌株N522所产抗菌活性物质为多肽,分子量在3-5 k D之间,并且该抗菌活性物质对p H和温度稳定性良好。晒盐场沉积物中分离得到的中度嗜盐菌H.dabanensis N522可作为开发抗菌药物的潜在新来源。
基金the National High Technology Research and Development Program of China (Grant No. 2003AA241150)International Cooperation Program for Science and Technology (Grant No.2006DFA31060)
文摘The Na+/H+ antiporter plays key roles in maintaining low cytoplasmic Na+ level and pH homeostasis,while little is known about the Carboxyl-terminal hydrophilic tails of prokaryotic antiporters.In our previous study,the first Na+/H+ antiporter gene nhaH from moderate halophiles was cloned from Halo-bacillus dabanensis D-8 by functional complementation.A topological model suggested that only nine amino acid residues(395PLIKKLGMI403) existed in the hydrophilic C-terminal domain of NhaH.The C-terminal truncated mutant of NhaH was constructed by PCR strategy and designated as nhaH△C.Salt tolerance experiment demonstrated that the deletion of hydrophilic C-terminal nine amino acid resi-dues significantly inhibited the complementation ability of E.coli KNabc,in which three main Na+/H+ antiporters nhaA,nhaB and chaA were deleted.Everted membrane vesicles prepared from E.coli KNabc/nhaH△C decreased both Na+/H+ and Li+/H+ exchange activities of NhaH,and also resulted in an acidic shift of its pH profile for Na+,indicating a critical role of the short C-terminal domain of NhaH antiporter in alkali cation binding/translocation and pH sensing.
