The Cd-tolerant and sodium alginate(SA)-synthesizing Pseudomonas putida XMS-1was characterized for Cd immobilization in solution.Additionally,the XMS-1 mutant constructed by deleting SA-synthesizing regulatory gene al...The Cd-tolerant and sodium alginate(SA)-synthesizing Pseudomonas putida XMS-1was characterized for Cd immobilization in solution.Additionally,the XMS-1 mutant constructed by deleting SA-synthesizing regulatory gene algB(△algB)were characterized for their roles in Cd uptake in Chinese chive in the Cd-contaminated soil.Between 12 and 48 h of incubation,the XMS-1△algBmutant significantly reduced solution Cd concentrations by 81%compared with the control but increased the Cd concentrations by 36%compared with XMS-1.After 48 h of incubation,the XMS-1△algB mutant significantly increased the Cd concentration by 36%and decreased the expolysaccharide(EPS)and SA concentrations by 30%-32%and cell surface-adsorbed Cd content by 24%in the Cd-containing medium,compared with XMS-1.The XMS-1△algB mutant significantly increased the root and leaf Cd contents of Chinese chive by 15%-50%and exchangeable Cd content by 17%and decreased the Fe-Mn oxideand organic matter-bound Cd contents by 17%-23%,compared with XMS-1.Furthermore,the XMS-1△algBmutant significantly decreased the EPS content by 33%,copies of algD gene involved in EPS production by 7.7-fold,and the interactions between the amino,hydroxyl,and carbonyl groups and Cd in the Cd-contaminated soil,compared with XMS-1.These results suggested that algB promoted XMS-1-mediated Cd-stabilizing related gene abundance and interactions between soil and Cd and decreased Cd uptake in Chinese chive.These findings may provide an effective and eco-friendly way using SA-producing bacteria for safe production of vegetables in the Cd-polluted soil.展开更多
【目的】以苯、甲苯和苯乙烯为唯一碳源,从工业石油废水中筛选苯系物降解菌,分析其降解特性,探讨底物间相互作用对降解情况的影响。【方法】经生理生化和16S r RNA基因分析进行菌种鉴定,采用顶空气相色谱法测定苯系物含量,通过细胞的疏...【目的】以苯、甲苯和苯乙烯为唯一碳源,从工业石油废水中筛选苯系物降解菌,分析其降解特性,探讨底物间相互作用对降解情况的影响。【方法】经生理生化和16S r RNA基因分析进行菌种鉴定,采用顶空气相色谱法测定苯系物含量,通过细胞的疏水性、乳化能力、排油圈及透射电镜观察分析菌株降解特性。【结果】经鉴定该菌为Pseudomonas putida,命名为SW-3菌株。最适降解条件下,单位菌体对苯、甲苯和苯乙烯的最大降解速率分别为0.072、0.035和0.019 g/(L·h),苯系混合物的总降解率达79.99%。底物降解实验表明,苯可促进甲苯和苯乙烯的降解,而苯乙烯则能抑制甲苯的降解。菌株的吸附、摄取和降解特性的研究发现,菌株SW-3在自身分泌的表面活性剂的协助下以耗能的方式运输苯。【结论】菌株SW-3具有产生表面活性剂和降解苯系物的能力,且底物间的相互作用能够显著影响菌株对不同底物的降解。展开更多
基金supported by the National Natural Science Foundation of China(No.41977199).
文摘The Cd-tolerant and sodium alginate(SA)-synthesizing Pseudomonas putida XMS-1was characterized for Cd immobilization in solution.Additionally,the XMS-1 mutant constructed by deleting SA-synthesizing regulatory gene algB(△algB)were characterized for their roles in Cd uptake in Chinese chive in the Cd-contaminated soil.Between 12 and 48 h of incubation,the XMS-1△algBmutant significantly reduced solution Cd concentrations by 81%compared with the control but increased the Cd concentrations by 36%compared with XMS-1.After 48 h of incubation,the XMS-1△algB mutant significantly increased the Cd concentration by 36%and decreased the expolysaccharide(EPS)and SA concentrations by 30%-32%and cell surface-adsorbed Cd content by 24%in the Cd-containing medium,compared with XMS-1.The XMS-1△algB mutant significantly increased the root and leaf Cd contents of Chinese chive by 15%-50%and exchangeable Cd content by 17%and decreased the Fe-Mn oxideand organic matter-bound Cd contents by 17%-23%,compared with XMS-1.Furthermore,the XMS-1△algBmutant significantly decreased the EPS content by 33%,copies of algD gene involved in EPS production by 7.7-fold,and the interactions between the amino,hydroxyl,and carbonyl groups and Cd in the Cd-contaminated soil,compared with XMS-1.These results suggested that algB promoted XMS-1-mediated Cd-stabilizing related gene abundance and interactions between soil and Cd and decreased Cd uptake in Chinese chive.These findings may provide an effective and eco-friendly way using SA-producing bacteria for safe production of vegetables in the Cd-polluted soil.
基金National Natural Science Foundation of China(No.21206055)National High Technology Research and Development Program of China(863 Program)(No.2011AA02A211)~~
文摘【目的】以苯、甲苯和苯乙烯为唯一碳源,从工业石油废水中筛选苯系物降解菌,分析其降解特性,探讨底物间相互作用对降解情况的影响。【方法】经生理生化和16S r RNA基因分析进行菌种鉴定,采用顶空气相色谱法测定苯系物含量,通过细胞的疏水性、乳化能力、排油圈及透射电镜观察分析菌株降解特性。【结果】经鉴定该菌为Pseudomonas putida,命名为SW-3菌株。最适降解条件下,单位菌体对苯、甲苯和苯乙烯的最大降解速率分别为0.072、0.035和0.019 g/(L·h),苯系混合物的总降解率达79.99%。底物降解实验表明,苯可促进甲苯和苯乙烯的降解,而苯乙烯则能抑制甲苯的降解。菌株的吸附、摄取和降解特性的研究发现,菌株SW-3在自身分泌的表面活性剂的协助下以耗能的方式运输苯。【结论】菌株SW-3具有产生表面活性剂和降解苯系物的能力,且底物间的相互作用能够显著影响菌株对不同底物的降解。
