A promising microalgal strain isolated from fresh water,which can grow both autotrophically on inorganic carbon under lighting and heterotrophically on organic carbon without lighting,was identified as Chlorella sp.US...A promising microalgal strain isolated from fresh water,which can grow both autotrophically on inorganic carbon under lighting and heterotrophically on organic carbon without lighting,was identified as Chlorella sp.USTB-01 with the phylogenetic analysis based on 18S ribosomal ribonucleic acid(rRNA)gene sequences.In the heterotrophic batch culture,more than 20.0 g·L^(-1)of cell dry weight concentration(DWC)of Chlorella sp.USTB-01 was obtained at day 5,and which was used directly to seed the autotrophic culture.A novel fermentor-helical combined photobioreactor was established and used to cultivate Chlorella sp.USTB-01 for the fixation of carbon dioxide(CO_(2)).It showed that the autotrophic growth of Chlorella sp.USTB-01 in the combined photobioreactor was more effective than that in the fermentor alone and the maximum DWC of 2.5 g·L^(-1)was obtained at day 6.The highest CO_(2)fixation of 95%appeared on day 1 in the exponential growth phases of Chlorella sp.USTB-01 and 49.8%protein was found in the harvested microalgal cells.展开更多
A promising bacterial strain for the biodegradation of Microcystins(MCs)was isolated from Dianchi lake in China and identified as Sphingopyxis sp.USTB-05 by the analysis of 16s rDNA.Initial MC-RR of 42.3 mg·L -1 ...A promising bacterial strain for the biodegradation of Microcystins(MCs)was isolated from Dianchi lake in China and identified as Sphingopyxis sp.USTB-05 by the analysis of 16s rDNA.Initial MC-RR of 42.3 mg·L -1 was completely degraded by USTB-05 within 36 h,which was a relatively high biodegradation rate of MC-RR.With the cell-free extract(CE)of Sphingopyxis sp.USTB-05,MC-RR was biodegraded at a more rapid biodegradation rate compared with its strain,so that initial MC-RR of 42.3 mg·L -1 was completely biodegraded within 10 h.During the bio-reaction of MC-RR catalyzed by CE,two intermediate metabolites and a dead-end product of MC-RR were observed on HPLC profiles and all of them had similar scanning profiles in the wavelength from 200 to 300 nm,indicating that the group of Adda in all products of MC-RR remained intact.展开更多
Harmful cyanobacterial blooms are a growing environmental problem worldwide in natural waters, the biodegradation is found to be the most efficient method for removing microcystins 0VICs） produced by harmful cyanobac...Harmful cyanobacterial blooms are a growing environmental problem worldwide in natural waters, the biodegradation is found to be the most efficient method for removing microcystins 0VICs） produced by harmful cyanobacteria. Based on the isolation of a promising bacterial strain of Sphingopyxis sp. USTB-05 for biodegrading MCs, we for the first time cloned and expressed a gene USTB-O5-A （HM245411） that is responsible for the first step in the biodegradation of microcystin LR （MC-LR） in E. coli DH5ct, with a cloning vector of pGEM-T easy and an expression vector of pGEX-4T-1, respectively. The cell-free extracts （CE） of recombinant E. coli DH5ct containing USTB-O5-A had high activity for biodegrading MC-LR. The initial MC-LR concentration of 40 mg/L was completely biodegraded within 1 hr in the presence of CE with a protein concentration of 0.35 mg/mL. Based on an analysis of the liquid chromatogram-mass spectrum （LC-MS）, the enzyme encoded by gene USTB-O5-A was found to be active in cleaving the target peptide bond between 3-amino-9-methoxy-2,6, 8-trimethyl-10-phenyl-deca-4,6-dienoic acid （Adda） and arginine of MC-LR, and converting cyclic MC-LR to linear MC-LR as a first product that is much less toxic than parent MC-LR, which offered direct evidence for the first step on the pathway of MC-LR biodegradation by Sphingopyxis sp. USTB-05.展开更多
A strain, USTB-05, isolated from Lake Dianchi, China, degraded the cyanobacterial toxin microcystin-RR （MC-RR） at the rate of 16.7 mg/L per day. Analysis of 16S rDNA sequence showed that the strain was Sphingopyxis ...A strain, USTB-05, isolated from Lake Dianchi, China, degraded the cyanobacterial toxin microcystin-RR （MC-RR） at the rate of 16.7 mg/L per day. Analysis of 16S rDNA sequence showed that the strain was Sphingopyxis sp. Enzymatic degradation pathways for MC-RR by Sphingopyxis sp. USTB-05 were identified. Adda-Arg peptide bond of MC-RR was cleaved and then a hydrogen and a hydroxyl were combined onto the NH2 group of Adda and the carboxyl group of arginine to form a linear molecule as intermediate product within the first few hours. Then, through dehydration reaction, two hydrogen of amino group on arginine reacted with adjacent hydroxyl on carbon to form a linear MC-RR with two small peptide rings as the final product after 24 hr. These biodegradation pathways were different from those reported for other strains, implying that MC-RR may undergo different transformations and different products were formed due to various bacteria in natural lakes and reservoirs.展开更多
The detailed mechanisms that facilitate the heat tolerance of terrestrial cyanobacteria have not been completely elucidated, although several reports have revealed aspects of the heat tolerance mechanisms of several o...The detailed mechanisms that facilitate the heat tolerance of terrestrial cyanobacteria have not been completely elucidated, although several reports have revealed aspects of the heat tolerance mechanisms of several other organisms. The dormant cells, called akinetes, of the terrestrial cyanobacterium Nostoc sp. HK-01 can revive after dry heat exposure at 100℃ for more than 10 h. We investigated the compatible solutes that protect the biomolecules in Nostoc sp. HK-01 akinetes using colonies containing various proportions of akinetes. We extracted the intracellular substances from each colony with 80% ethanol, which we purified with a series of analytical columns and analyzed by high-performance liquid chromatography and liquid chromatography-electrospray ionization-mass spectrometry. The compatible solutes were screened for their ability to prevent protein aggregation upon heating using the model enzyme lactate dehydrogenase. We detected an accumulation of glucosylglycerol, betaine, and glycine in akinetes. In addition, we confirmed that betaine, glycine, sucrose, and trehalose contributed to the prevention of the protein aggregation. The levels of sucrose and glycine in the colonies were approximately 1000× higher than those of glucosylglycerol, betaine, or trehalose. Our results indicated that sucrose and glycine are the main compatible solutes in the hydrophilic fractions of the cell extracts of Nostoc sp. HK-01 akinetes.展开更多
以耐铬(VI)菌株Serratia sp. CM01为研究对象,探究其全基因组信息,挖掘其潜在的铬代谢相关基因。本研究采用基因组测序技术对CM01进行全基因组测序并分析其基因序列特征;同时,结合前期差异蛋白研究结果,进行铬代谢相关基因分析。测序结...以耐铬(VI)菌株Serratia sp. CM01为研究对象,探究其全基因组信息,挖掘其潜在的铬代谢相关基因。本研究采用基因组测序技术对CM01进行全基因组测序并分析其基因序列特征;同时,结合前期差异蛋白研究结果,进行铬代谢相关基因分析。测序结果表明,CM01基因组大小为4,902,254 bp,预测编码蛋白序列的基因有4547个;蛋白功能注释结果显示其涉及氧化还原、氨基酸代谢、碳水化合物和能量代谢编码的基因有较高的占比。结合前期蛋白组学的结果,筛选出了12个与铬代谢相关的基因。qRT-PCR分析结果显示,在Cr(VI)胁迫下,ChrA1、Srpc、GrxA和NemA基因的表达上调。CM01基因组全序列已上传至NCBI,序列号:PRJNA675313。本研究通过对CM01的基因组序列分析,为全面了解细菌的铬代谢机制提供基础,为修复环境铬污染的新生物技术提供理论依据。The study focused on the chromium (VI)-resistant bacterial strain Serratia sp. CM01 to explore its whole-genome information and to mine its potential chromium metabolism-related genes. In this research, genomic sequencing technology was employed to perform whole-genome sequencing on CM01 and to analyze its gene sequence characteristics. Additionally, the results from previous differential protein studies were integrated to analyze genes related to chromium metabolism. The sequencing results indicated that the CM01 genome is 4,902,254 base pairs in size, with 4547 genes predicted to encode protein sequences. Protein function annotation revealed a high proportion of genes involved in oxidation-reduction, amino acid metabolism, carbohydrate metabolism, and energy metabolism. Combining the outcomes from previous proteomics studies, 12 genes related to chromium metabolism were identified. Quantitative real-time PCR analysis showed that the expression of ChrA1, Srpc, GrxA, and NemA genes was upregulated under Cr(VI) stress. The complete genome sequence of CM01 has been uploaded to NCBI with the accession number PRJNA675313. Through the genomic sequence analysis of CM01, this study provides a foundation for a comprehensive understanding of bacterial chromium metabolism mechanisms and offers a theoretical basis for the development of new biotechnologies for the remediation of environmental chromium pollution.展开更多
基金This research was supported by PetroChina Innovation Foundation(2009D-5006-04-02)the Fundamental Research Funds for the Central Universities and the Metallurgical Foundation of University of Science and Technology Beijing.
文摘A promising microalgal strain isolated from fresh water,which can grow both autotrophically on inorganic carbon under lighting and heterotrophically on organic carbon without lighting,was identified as Chlorella sp.USTB-01 with the phylogenetic analysis based on 18S ribosomal ribonucleic acid(rRNA)gene sequences.In the heterotrophic batch culture,more than 20.0 g·L^(-1)of cell dry weight concentration(DWC)of Chlorella sp.USTB-01 was obtained at day 5,and which was used directly to seed the autotrophic culture.A novel fermentor-helical combined photobioreactor was established and used to cultivate Chlorella sp.USTB-01 for the fixation of carbon dioxide(CO_(2)).It showed that the autotrophic growth of Chlorella sp.USTB-01 in the combined photobioreactor was more effective than that in the fermentor alone and the maximum DWC of 2.5 g·L^(-1)was obtained at day 6.The highest CO_(2)fixation of 95%appeared on day 1 in the exponential growth phases of Chlorella sp.USTB-01 and 49.8%protein was found in the harvested microalgal cells.
基金Supported by the State Key Development Program for Basic Research of China（2008CB418105） the National Natural Science Foundation of China（203777008 20621703）+1 种基金 the State Key Joint Laboratory of Environment Simulation and Pollution Control（09K08ESPCT） the Educational Committee of Beijing
文摘A promising bacterial strain for the biodegradation of Microcystins(MCs)was isolated from Dianchi lake in China and identified as Sphingopyxis sp.USTB-05 by the analysis of 16s rDNA.Initial MC-RR of 42.3 mg·L -1 was completely degraded by USTB-05 within 36 h,which was a relatively high biodegradation rate of MC-RR.With the cell-free extract(CE)of Sphingopyxis sp.USTB-05,MC-RR was biodegraded at a more rapid biodegradation rate compared with its strain,so that initial MC-RR of 42.3 mg·L -1 was completely biodegraded within 10 h.During the bio-reaction of MC-RR catalyzed by CE,two intermediate metabolites and a dead-end product of MC-RR were observed on HPLC profiles and all of them had similar scanning profiles in the wavelength from 200 to 300 nm,indicating that the group of Adda in all products of MC-RR remained intact.
基金supported by the National Natural Science Foundation of China (No. 21177009)
文摘Harmful cyanobacterial blooms are a growing environmental problem worldwide in natural waters, the biodegradation is found to be the most efficient method for removing microcystins 0VICs） produced by harmful cyanobacteria. Based on the isolation of a promising bacterial strain of Sphingopyxis sp. USTB-05 for biodegrading MCs, we for the first time cloned and expressed a gene USTB-O5-A （HM245411） that is responsible for the first step in the biodegradation of microcystin LR （MC-LR） in E. coli DH5ct, with a cloning vector of pGEM-T easy and an expression vector of pGEX-4T-1, respectively. The cell-free extracts （CE） of recombinant E. coli DH5ct containing USTB-O5-A had high activity for biodegrading MC-LR. The initial MC-LR concentration of 40 mg/L was completely biodegraded within 1 hr in the presence of CE with a protein concentration of 0.35 mg/mL. Based on an analysis of the liquid chromatogram-mass spectrum （LC-MS）, the enzyme encoded by gene USTB-O5-A was found to be active in cleaving the target peptide bond between 3-amino-9-methoxy-2,6, 8-trimethyl-10-phenyl-deca-4,6-dienoic acid （Adda） and arginine of MC-LR, and converting cyclic MC-LR to linear MC-LR as a first product that is much less toxic than parent MC-LR, which offered direct evidence for the first step on the pathway of MC-LR biodegradation by Sphingopyxis sp. USTB-05.
基金supported by the Chinese National Key Project for Basic Research (No.2008CB418105)the National Natural Science Foundation of China(No.20621703,20477050)the Important-Direction-Project funded by the Chinese Academy of Sciences
文摘A strain, USTB-05, isolated from Lake Dianchi, China, degraded the cyanobacterial toxin microcystin-RR （MC-RR） at the rate of 16.7 mg/L per day. Analysis of 16S rDNA sequence showed that the strain was Sphingopyxis sp. Enzymatic degradation pathways for MC-RR by Sphingopyxis sp. USTB-05 were identified. Adda-Arg peptide bond of MC-RR was cleaved and then a hydrogen and a hydroxyl were combined onto the NH2 group of Adda and the carboxyl group of arginine to form a linear molecule as intermediate product within the first few hours. Then, through dehydration reaction, two hydrogen of amino group on arginine reacted with adjacent hydroxyl on carbon to form a linear MC-RR with two small peptide rings as the final product after 24 hr. These biodegradation pathways were different from those reported for other strains, implying that MC-RR may undergo different transformations and different products were formed due to various bacteria in natural lakes and reservoirs.
文摘The detailed mechanisms that facilitate the heat tolerance of terrestrial cyanobacteria have not been completely elucidated, although several reports have revealed aspects of the heat tolerance mechanisms of several other organisms. The dormant cells, called akinetes, of the terrestrial cyanobacterium Nostoc sp. HK-01 can revive after dry heat exposure at 100℃ for more than 10 h. We investigated the compatible solutes that protect the biomolecules in Nostoc sp. HK-01 akinetes using colonies containing various proportions of akinetes. We extracted the intracellular substances from each colony with 80% ethanol, which we purified with a series of analytical columns and analyzed by high-performance liquid chromatography and liquid chromatography-electrospray ionization-mass spectrometry. The compatible solutes were screened for their ability to prevent protein aggregation upon heating using the model enzyme lactate dehydrogenase. We detected an accumulation of glucosylglycerol, betaine, and glycine in akinetes. In addition, we confirmed that betaine, glycine, sucrose, and trehalose contributed to the prevention of the protein aggregation. The levels of sucrose and glycine in the colonies were approximately 1000× higher than those of glucosylglycerol, betaine, or trehalose. Our results indicated that sucrose and glycine are the main compatible solutes in the hydrophilic fractions of the cell extracts of Nostoc sp. HK-01 akinetes.
文摘以耐铬(VI)菌株Serratia sp. CM01为研究对象,探究其全基因组信息,挖掘其潜在的铬代谢相关基因。本研究采用基因组测序技术对CM01进行全基因组测序并分析其基因序列特征;同时,结合前期差异蛋白研究结果,进行铬代谢相关基因分析。测序结果表明,CM01基因组大小为4,902,254 bp,预测编码蛋白序列的基因有4547个;蛋白功能注释结果显示其涉及氧化还原、氨基酸代谢、碳水化合物和能量代谢编码的基因有较高的占比。结合前期蛋白组学的结果,筛选出了12个与铬代谢相关的基因。qRT-PCR分析结果显示,在Cr(VI)胁迫下,ChrA1、Srpc、GrxA和NemA基因的表达上调。CM01基因组全序列已上传至NCBI,序列号:PRJNA675313。本研究通过对CM01的基因组序列分析,为全面了解细菌的铬代谢机制提供基础,为修复环境铬污染的新生物技术提供理论依据。The study focused on the chromium (VI)-resistant bacterial strain Serratia sp. CM01 to explore its whole-genome information and to mine its potential chromium metabolism-related genes. In this research, genomic sequencing technology was employed to perform whole-genome sequencing on CM01 and to analyze its gene sequence characteristics. Additionally, the results from previous differential protein studies were integrated to analyze genes related to chromium metabolism. The sequencing results indicated that the CM01 genome is 4,902,254 base pairs in size, with 4547 genes predicted to encode protein sequences. Protein function annotation revealed a high proportion of genes involved in oxidation-reduction, amino acid metabolism, carbohydrate metabolism, and energy metabolism. Combining the outcomes from previous proteomics studies, 12 genes related to chromium metabolism were identified. Quantitative real-time PCR analysis showed that the expression of ChrA1, Srpc, GrxA, and NemA genes was upregulated under Cr(VI) stress. The complete genome sequence of CM01 has been uploaded to NCBI with the accession number PRJNA675313. Through the genomic sequence analysis of CM01, this study provides a foundation for a comprehensive understanding of bacterial chromium metabolism mechanisms and offers a theoretical basis for the development of new biotechnologies for the remediation of environmental chromium pollution.
