In order to explore the salt tolerance mechanism of Bacillus cereus LBR-4 with salinity of 14%NaCl,differential proteomic analysis of the whole protein of LBR-4 strain expressed under 14%NaCl high salinity condition a...In order to explore the salt tolerance mechanism of Bacillus cereus LBR-4 with salinity of 14%NaCl,differential proteomic analysis of the whole protein of LBR-4 strain expressed under 14%NaCl high salinity condition and normalculture condition(1%NaCl)was studied by two-dimensional electrophoresis and mass spectrometry.The isoelectric point of most detected proteins was between pH 4-7 and the molecular weight distribution was 10-70 ku.Compared with the normal culture condition,the expression level of 118 protein spots in the whole protein expression map changed significantly(accounting for 25.2%of the total protein spots).The expression level of 78 protein spots increased significantly,including 22 new protein spots that appeared under high salt stress.The expression levels of 40 protein spots decreased significantly,including 18 protein spots that disappeared under high salt stress.By mass spectrometry,six distinct differentially expressed protein spotswere dihydroxy acid dehydratase,cell division protein FtsZ,iron sulfur cluster synthesis protein SufD,unknown carboxylase YngE,hypothetical acetaldehyde dehydrogenase DhaS and phenylalanine acid tRNA ligase alpha subunit.It was speculated that under high salt stress,the cells had protective measures and the secretion of intracellular compatible solutes increased.The iron and sulfur clusters involved in various physiological reactions also activated the stressful suf synthesis pathway,and therate of cell division and reproduction was also slowed down and ensured the normal progress of physiological reactions inthe cells.展开更多
Strain QCG of the aerobic bacteria Bacillus cereus is capable of producing l-naphthol from naphtha-lene,this strain was first isolated and characterized in this study.Strain QCG was mutagenized to enhance l-naphthol p...Strain QCG of the aerobic bacteria Bacillus cereus is capable of producing l-naphthol from naphtha-lene,this strain was first isolated and characterized in this study.Strain QCG was mutagenized to enhance l-naphthol production,using atmospheric and room temperature plasma(ARTP)technology.Then,a microbial clone screening system was used to accelerate the operation.Meanwhile,a novel color-mediated high-throughput screening using 4-aminoantipyrine was performed to screen mutants.The optimal mutant strain QCG4 produced 19.58土0.34 mg·L-1-naphthol from naphthalene that was 47.32%higher than that of the original strain(13.29+0.28 mg·L-1).In addition,the optimal conditions for l-naphthol production via whole-cell catalysis of strain QCG4 were determined to be an OD600 of40,150 mg.L I naphthalene,and 7.5%dimethyl formamide as a co-solvent at pH 7.5 and 26℃ for 3 h,resulting in 41.18士0.12 mg·L-l-naphthol,i.e.,the mutant strain produces a 2.1-fold higher yield compared to the original strain.展开更多
基金Supported by Heilongjiang Province National Science Foundation(LH2020C007)。
文摘In order to explore the salt tolerance mechanism of Bacillus cereus LBR-4 with salinity of 14%NaCl,differential proteomic analysis of the whole protein of LBR-4 strain expressed under 14%NaCl high salinity condition and normalculture condition(1%NaCl)was studied by two-dimensional electrophoresis and mass spectrometry.The isoelectric point of most detected proteins was between pH 4-7 and the molecular weight distribution was 10-70 ku.Compared with the normal culture condition,the expression level of 118 protein spots in the whole protein expression map changed significantly(accounting for 25.2%of the total protein spots).The expression level of 78 protein spots increased significantly,including 22 new protein spots that appeared under high salt stress.The expression levels of 40 protein spots decreased significantly,including 18 protein spots that disappeared under high salt stress.By mass spectrometry,six distinct differentially expressed protein spotswere dihydroxy acid dehydratase,cell division protein FtsZ,iron sulfur cluster synthesis protein SufD,unknown carboxylase YngE,hypothetical acetaldehyde dehydrogenase DhaS and phenylalanine acid tRNA ligase alpha subunit.It was speculated that under high salt stress,the cells had protective measures and the secretion of intracellular compatible solutes increased.The iron and sulfur clusters involved in various physiological reactions also activated the stressful suf synthesis pathway,and therate of cell division and reproduction was also slowed down and ensured the normal progress of physiological reactions inthe cells.
基金This work was supported by COVESTRO,the National Key Research and Development Program(Grant No.2016YFA0204300)the Jiangsu Province Natural Science Foundation for Youths(No.BK20170997)China Postdoctoral Science Foundation(Nos.2018M642237 and 2017T100359).
文摘Strain QCG of the aerobic bacteria Bacillus cereus is capable of producing l-naphthol from naphtha-lene,this strain was first isolated and characterized in this study.Strain QCG was mutagenized to enhance l-naphthol production,using atmospheric and room temperature plasma(ARTP)technology.Then,a microbial clone screening system was used to accelerate the operation.Meanwhile,a novel color-mediated high-throughput screening using 4-aminoantipyrine was performed to screen mutants.The optimal mutant strain QCG4 produced 19.58土0.34 mg·L-1-naphthol from naphthalene that was 47.32%higher than that of the original strain(13.29+0.28 mg·L-1).In addition,the optimal conditions for l-naphthol production via whole-cell catalysis of strain QCG4 were determined to be an OD600 of40,150 mg.L I naphthalene,and 7.5%dimethyl formamide as a co-solvent at pH 7.5 and 26℃ for 3 h,resulting in 41.18士0.12 mg·L-l-naphthol,i.e.,the mutant strain produces a 2.1-fold higher yield compared to the original strain.
