选取丙烯酰胺(AM)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)、含非离子基团抗盐单体(KYD)、十八烷基二甲基烯丙基氯化铵(DMAAC-18)4种单体,采用水溶液聚合的方法得到聚合物,并将其作为水基钻井液用降滤失剂;通过单因素法对聚合反应条件进行优化...选取丙烯酰胺(AM)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)、含非离子基团抗盐单体(KYD)、十八烷基二甲基烯丙基氯化铵(DMAAC-18)4种单体,采用水溶液聚合的方法得到聚合物,并将其作为水基钻井液用降滤失剂;通过单因素法对聚合反应条件进行优化,利用傅里叶红外光谱仪对产物的结构进行分析,并对聚合物的降滤失性能进行评价。结果表明,淡水基浆中聚合物质量分数为1.2%时,API滤失量为9.6 m L;在35%的盐水基浆中,API滤失量为9.5 m L;在180℃条件下老化16 h,API滤失量为13.5 m L;通过对基浆中膨润土粒径分布和滤饼微观形貌的分析,确定了聚合物是通过提升滤饼的致密性来降低API滤失量。展开更多
In industrial fermentation processes,microorganisms often encounter acid stress,which significantly impact their productivity.This study focused on the acid-resistant module composed of small RNA(sRNA)DsrA and the sRN...In industrial fermentation processes,microorganisms often encounter acid stress,which significantly impact their productivity.This study focused on the acid-resistant module composed of small RNA(sRNA)DsrA and the sRNA chaperone Hfq.Our previous study had shown that this module improved the cell growth of Escherichia coli MG1655 at low pH,but failed to obtain this desired phenotype in industrial strains.Here,we performed a quantitative analysis of DsrA-Hfq module to determine the optimal expression mode.We then assessed the po-tential of the CymR-based negative auto-regulation(NAR)circuit for industrial application,under different media,strains and pH levels.Growth assay at pH 4.5 revealed that NAR-05D04H circuit was the best acid-resistant circuit to improve the cell growth of E.coli MG1655.This circuit was robust and worked well in the industrial lysine-producing strain E.coli SCEcL3 at a starting pH of 6.8 and without pH control,resulting in a 250%increase in lysine titer and comparable biomass in shaking flask fermentation compared to the parent strain.This study showed the practical application of NAR circuit in regulating DsrA-Hfq module,effectively and robustly improving the acid tolerance of industrial strains,which provides a new approach for breeding in-dustrial strains with tolerance phenotype.展开更多
Purpose:Vibrio vulnificus (V. Vulnificus) infection is characterized by rapid onset, aggressive progression, and challenging treatment. Bacterial resistance poses a significant challenge for clinical anti-infection tr...Purpose:Vibrio vulnificus (V. Vulnificus) infection is characterized by rapid onset, aggressive progression, and challenging treatment. Bacterial resistance poses a significant challenge for clinical anti-infection treatment and is thus the subject of research. Enhancing host infection tolerance represents a novel infection prevention strategy to improve patient survival. Our team initially identified cytochrome P4501A1 (CYP1A1) as an important target owing to its negative modulation of the body''s infection tolerance. This study explored the superior effects of the CYP1A1 inhibitor bergamottin compared to antibiotic combination therapy on the survival of mice infected with multidrug-resistantV. Vulnificus and the protection of their vital organs.Methods:An increasing concentration gradient method was used to induce multidrug-resistantV. Vulnificus development. We established a lethal infection model in C57BL/6J male mice and evaluated the effect of bergamottin on mouse survival. A mild infection model was established in C57BL/6J male mice, and the serum levels of creatinine, urea nitrogen, aspartate aminotransferase, and alanine aminotransferase were determined using enzyme-linked immunosorbent assay to evaluate the effect of bergamottin on liver and kidney function. The morphological changes induced in the presence of bergamottin in mouse organs were evaluated by hematoxylin and eosin staining of liver and kidney tissues. The bacterial growth curve and organ load determination were used to evaluate whether bergamottin has a direct antibacterial effect on multidrug-resistantV. Vulnificus. Quantification of inflammatory factors in serum by enzyme-linked immunosorbent assay and the expression levels of inflammatory factors in liver and kidney tissues by real-time quantitative polymerase chain reaction were performed to evaluate the effect of bergamottin on inflammatory factor levels. Western blot analysis of IκBα, phosphorylated IκBα, p65, and phosphorylated p65 protein expression in liver and kidney tissues a展开更多
文摘选取丙烯酰胺(AM)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)、含非离子基团抗盐单体(KYD)、十八烷基二甲基烯丙基氯化铵(DMAAC-18)4种单体,采用水溶液聚合的方法得到聚合物,并将其作为水基钻井液用降滤失剂;通过单因素法对聚合反应条件进行优化,利用傅里叶红外光谱仪对产物的结构进行分析,并对聚合物的降滤失性能进行评价。结果表明,淡水基浆中聚合物质量分数为1.2%时,API滤失量为9.6 m L;在35%的盐水基浆中,API滤失量为9.5 m L;在180℃条件下老化16 h,API滤失量为13.5 m L;通过对基浆中膨润土粒径分布和滤饼微观形貌的分析,确定了聚合物是通过提升滤饼的致密性来降低API滤失量。
基金supported by National Key R&D Program of China(2018YFA0901000,2022YFC2104800).
文摘In industrial fermentation processes,microorganisms often encounter acid stress,which significantly impact their productivity.This study focused on the acid-resistant module composed of small RNA(sRNA)DsrA and the sRNA chaperone Hfq.Our previous study had shown that this module improved the cell growth of Escherichia coli MG1655 at low pH,but failed to obtain this desired phenotype in industrial strains.Here,we performed a quantitative analysis of DsrA-Hfq module to determine the optimal expression mode.We then assessed the po-tential of the CymR-based negative auto-regulation(NAR)circuit for industrial application,under different media,strains and pH levels.Growth assay at pH 4.5 revealed that NAR-05D04H circuit was the best acid-resistant circuit to improve the cell growth of E.coli MG1655.This circuit was robust and worked well in the industrial lysine-producing strain E.coli SCEcL3 at a starting pH of 6.8 and without pH control,resulting in a 250%increase in lysine titer and comparable biomass in shaking flask fermentation compared to the parent strain.This study showed the practical application of NAR circuit in regulating DsrA-Hfq module,effectively and robustly improving the acid tolerance of industrial strains,which provides a new approach for breeding in-dustrial strains with tolerance phenotype.
基金supported by the National Natural Science Foundation of China(grant number:82104247)Chongqing Talent Innovation Leading Plan(grant number:cstc2021ycjhbgzxm0340)+2 种基金Chongqing Doctor Express Project(grant number:CSTB2022BSXM-JCX0024)Hainan Clinical Medical Research Center Project(grant number:LCYX202205)Hainan Province Health Industry Research Project(grant number:22A200082).
文摘Purpose:Vibrio vulnificus (V. Vulnificus) infection is characterized by rapid onset, aggressive progression, and challenging treatment. Bacterial resistance poses a significant challenge for clinical anti-infection treatment and is thus the subject of research. Enhancing host infection tolerance represents a novel infection prevention strategy to improve patient survival. Our team initially identified cytochrome P4501A1 (CYP1A1) as an important target owing to its negative modulation of the body''s infection tolerance. This study explored the superior effects of the CYP1A1 inhibitor bergamottin compared to antibiotic combination therapy on the survival of mice infected with multidrug-resistantV. Vulnificus and the protection of their vital organs.Methods:An increasing concentration gradient method was used to induce multidrug-resistantV. Vulnificus development. We established a lethal infection model in C57BL/6J male mice and evaluated the effect of bergamottin on mouse survival. A mild infection model was established in C57BL/6J male mice, and the serum levels of creatinine, urea nitrogen, aspartate aminotransferase, and alanine aminotransferase were determined using enzyme-linked immunosorbent assay to evaluate the effect of bergamottin on liver and kidney function. The morphological changes induced in the presence of bergamottin in mouse organs were evaluated by hematoxylin and eosin staining of liver and kidney tissues. The bacterial growth curve and organ load determination were used to evaluate whether bergamottin has a direct antibacterial effect on multidrug-resistantV. Vulnificus. Quantification of inflammatory factors in serum by enzyme-linked immunosorbent assay and the expression levels of inflammatory factors in liver and kidney tissues by real-time quantitative polymerase chain reaction were performed to evaluate the effect of bergamottin on inflammatory factor levels. Western blot analysis of IκBα, phosphorylated IκBα, p65, and phosphorylated p65 protein expression in liver and kidney tissues a
