为研究Lactobacillus plantarum SL32-2自溶酶的酶学性质及底物特异性,以该细菌细胞为底物分析其自溶酶的最适温度及最适pH,结合该菌株在有无外加自溶酶、自溶前后还原糖和氨基酸的变化以及对4种底物的敏感性,分析其自溶酶的底物特异性...为研究Lactobacillus plantarum SL32-2自溶酶的酶学性质及底物特异性,以该细菌细胞为底物分析其自溶酶的最适温度及最适pH,结合该菌株在有无外加自溶酶、自溶前后还原糖和氨基酸的变化以及对4种底物的敏感性,分析其自溶酶的底物特异性。结果表明,L.plantarum SL32-2在对数早期培养4 h时,自溶度最高;其自溶酶的最适pH为7.5,最适温度为37℃;添加自溶酶后,L.plantarum SL32-2的自溶度增加了12.04%、还原糖和氨基酸分别增加了1.05和42.83倍;底物特异性分析发现,L.plantarum SL32-2自溶酶中β-N-乙酰葡萄糖胺酶、酰胺酶、羧肽酶、内肽酶的活性分别为0.0036、0.0027、1.1267和2.0987 U,表明作用于肽链的酶活性远高于作用于糖链的酶。因此,有望通过添加自溶酶的方式,控制酒醅中乳酸菌的过量生长。展开更多
Cell a utolysis plays important physiological roles in the life cycle of clostridial cells.Unders tanding the genetic ba-sis of the autolysis phenomenon of pathogenic Clostridi-um or solvent producing Clostridium cell...Cell a utolysis plays important physiological roles in the life cycle of clostridial cells.Unders tanding the genetic ba-sis of the autolysis phenomenon of pathogenic Clostridi-um or solvent producing Clostridium cells might provide new insights into this important species.Genes that might be involved in autolysis of Clostridium acetobutylicum,a model clostridial species,were investigated in this study.Twelve putative autolysin genes were predicted in C.ace-tobutylicum DSM 1731 genome through bioinformatics analysis.Of these 12 genes,gene SMB_G3117 was select-ed for testing the in tracellular autolysin activity,growth profi le,viable cell numbers,and cellular morphology.We found that overexpression of SMB_G3117 gene led to earlier ceased growth,signifi cantly increased number of dead cells,and clear electrolucent cavities,while disrup-tion of SMB_G3117 gene exhibited remarkably reduced intracellular autolysin activity.These results indicate that SMB_G3117 is a novel gene involved in cellular autolysis of C.acetobutylicum.展开更多
基金the National Natural Science Foundation of China(Grant No.31270107)the National High Technology Research and Development Program(863 Program)(No.2011AA02A208)Yanping Zhang is supported by grants from the Knowledge Innovation Program of the Chinese Academy of Sciences(No.KSCX2-EW-Q-14)。
文摘Cell a utolysis plays important physiological roles in the life cycle of clostridial cells.Unders tanding the genetic ba-sis of the autolysis phenomenon of pathogenic Clostridi-um or solvent producing Clostridium cells might provide new insights into this important species.Genes that might be involved in autolysis of Clostridium acetobutylicum,a model clostridial species,were investigated in this study.Twelve putative autolysin genes were predicted in C.ace-tobutylicum DSM 1731 genome through bioinformatics analysis.Of these 12 genes,gene SMB_G3117 was select-ed for testing the in tracellular autolysin activity,growth profi le,viable cell numbers,and cellular morphology.We found that overexpression of SMB_G3117 gene led to earlier ceased growth,signifi cantly increased number of dead cells,and clear electrolucent cavities,while disrup-tion of SMB_G3117 gene exhibited remarkably reduced intracellular autolysin activity.These results indicate that SMB_G3117 is a novel gene involved in cellular autolysis of C.acetobutylicum.
