蓝藻Synechococcussp.PCC7942 HCO3-高亲和转运蛋白操纵子基因cmpABCD是其CO2浓缩机制中的调控基因之一.本研究用携带潮霉素B磷酸转移酶基因(hygromyc in B pho transferase,hpt)筛选标记的同源双臂整合载体pUC-HATH转化蓝藻Synechococc...蓝藻Synechococcussp.PCC7942 HCO3-高亲和转运蛋白操纵子基因cmpABCD是其CO2浓缩机制中的调控基因之一.本研究用携带潮霉素B磷酸转移酶基因(hygromyc in B pho transferase,hpt)筛选标记的同源双臂整合载体pUC-HATH转化蓝藻Synechococcussp.PCC7942,以潮霉素B作为筛选试剂筛选出具潮霉素B抗性的转化藻,运用引物PCR方法证实潮霉素B磷酸转移酶基因表达盒通过质粒pUC-HATH的介导已定点插入蓝藻Synechococcussp.PCC7942基因组中,成功地构建了具有潮霉素B抗性的cmpBCD基因插入失活突变藻株.并最终通过比较野生藻Synechococcussp.PCC7942和突变藻Synechococcussp.PCC7942在不同Na2CO3浓度的改良BG-11培养基中生长特性,探讨了HCO3-高亲和转运蛋白操纵子cmpABCD基因失活对藻体生长的影响.展开更多
The unicellular cyanobacterium, Synechococcus elongatus PCC 7942(Syn7942), synthesizes sucrose as the only compatible solute under salt stress. A series of engineered Syn7942 strains for sucrose production were constr...The unicellular cyanobacterium, Synechococcus elongatus PCC 7942(Syn7942), synthesizes sucrose as the only compatible solute under salt stress. A series of engineered Syn7942 strains for sucrose production were constructed. The overexpression of the native sps(encoding a natively fused protein of sucrose phosphate synthase SPS and sucrose phosphate phosphatase SPP) in Syn7942 wild type caused a 93% improvement of sucrose productivity. The strain FL130 co-overexpressing sps and csc B(encoding a sucrose transporter) exhibited a 74% higher extracellular sucrose production than that overexpressing csc B only. Both results showed the significant improvement of sucrose productivity by the double functional protein SPS-SPP. Afterwards, FL130 was cultivated under a modified condition, and the cell-free culture medium containing 1.5 g L-1 sucrose was pre-treated with an acid hydrolysis technique. Cultivated with the neutralized hydrolysates as the starting media, two widely used microorganisms, Escherichia coli and Saccharomyces cerevisiae, showed a comparable growth with that in the control media supplemented with glucose. These results clearly demonstrated that the cell-free culture of sucrose-secreting cyanobacteria can be applied as starting media in microbial cultivation.展开更多
文摘蓝藻Synechococcussp.PCC7942 HCO3-高亲和转运蛋白操纵子基因cmpABCD是其CO2浓缩机制中的调控基因之一.本研究用携带潮霉素B磷酸转移酶基因(hygromyc in B pho transferase,hpt)筛选标记的同源双臂整合载体pUC-HATH转化蓝藻Synechococcussp.PCC7942,以潮霉素B作为筛选试剂筛选出具潮霉素B抗性的转化藻,运用引物PCR方法证实潮霉素B磷酸转移酶基因表达盒通过质粒pUC-HATH的介导已定点插入蓝藻Synechococcussp.PCC7942基因组中,成功地构建了具有潮霉素B抗性的cmpBCD基因插入失活突变藻株.并最终通过比较野生藻Synechococcussp.PCC7942和突变藻Synechococcussp.PCC7942在不同Na2CO3浓度的改良BG-11培养基中生长特性,探讨了HCO3-高亲和转运蛋白操纵子cmpABCD基因失活对藻体生长的影响.
基金supported by the Joint Sino-GermanResearch Project (GZ984 to X. Lu)the Excellent Youth Award of the Shandong Natural Science Foundation (JQ201306 to X. Lu)the Shandong Taishan Scholarship (X. Lu)
文摘The unicellular cyanobacterium, Synechococcus elongatus PCC 7942(Syn7942), synthesizes sucrose as the only compatible solute under salt stress. A series of engineered Syn7942 strains for sucrose production were constructed. The overexpression of the native sps(encoding a natively fused protein of sucrose phosphate synthase SPS and sucrose phosphate phosphatase SPP) in Syn7942 wild type caused a 93% improvement of sucrose productivity. The strain FL130 co-overexpressing sps and csc B(encoding a sucrose transporter) exhibited a 74% higher extracellular sucrose production than that overexpressing csc B only. Both results showed the significant improvement of sucrose productivity by the double functional protein SPS-SPP. Afterwards, FL130 was cultivated under a modified condition, and the cell-free culture medium containing 1.5 g L-1 sucrose was pre-treated with an acid hydrolysis technique. Cultivated with the neutralized hydrolysates as the starting media, two widely used microorganisms, Escherichia coli and Saccharomyces cerevisiae, showed a comparable growth with that in the control media supplemented with glucose. These results clearly demonstrated that the cell-free culture of sucrose-secreting cyanobacteria can be applied as starting media in microbial cultivation.
