摘要
从煤矸石中分离的耐Cd2+铜绿假单胞菌(Pseudomonas aeruginosa)ZGKD2具有多种重金属耐性,研究其铁载体产生特征和重金属耐性机制对于开发土壤重金属污染修复技术具有重要意义.在牛肉膏蛋白胨培养基中分别添加200～3 000μmol.L-1的Cd2+、Cu2+、Zn2+、Ni2+、Pb2+或Mn2+等重金属,ZGKD2菌株的最大生长量随着重金属浓度的增加而降低,不同浓度重金属对ZGKD2菌株产碱能力无明显影响.ZGKD2菌株生长进入稳定期时,用0、200、600、1 000μmol.L-1的Cd2+、Cu2+、Zn2+、Ni2+或0、1 000、2 000、3 000μmol.L-1的Pb2+、Mn2+处理2 h,SOD和CAT活性随重金属浓度增加而增加.ZGKD2菌株在MSA培养基中能产生铁载体,200～1 000μmol.L-1的重金属Cd2+或Zn2+可显著诱导铁载体的产生,Ni2+和Mn2+的作用较小,Cu2+则抑制;ZGKD2菌株的产铁载体能力与重金属耐性能力相关.这些结果表明ZGKD2菌株的产碱、产铁载体特性以及抗氧化酶活性提高可能是其耐重金属的主要机制.
The cadmium-resistant bacterium Pseudomonas aeruginosa strain ZGKD2 exhibiting tolerance to various heavy-metals was isolated from gangue pile of coal area in our laboratory.This bacterium could serve as an effective metal sequestering and growth-promoting bioinoculant for plants grown in metal-contaminated soil.However,the mechanism of heavy-metal tolerance is still unclear.When the beef extract-peptone medium was supplemented with 200-3 000 μmol·L-1 Cd2＋,Cu2＋,Zn2＋,Ni2＋,Pb2＋ or Mn2＋,the maximum biomass of strain ZGKD2 decreased with the increase of heavy-metal concentrations,while different concentrations of heavy-metals had no significant effect on its alkaline production.Stationary-phase cells of strain ZGKD2 were exposed to 0,200,600 and 1 000 μmol·L-1of Cd2＋,Cu2＋,Zn2＋ and Ni2＋ or 0,1 000,2 000 and 3 000 μmol·L-1 of Pb2＋ and Mn2＋ for 2 h,respectively.The activity of SOD and CAT increased in a heavy-metal-concentration-dependent manner,especially in the Cd2＋ and Cu2＋ treatments.The siderophore production of strain ZGKD2 in modified sugar-aspartic acid medium was enhanced by 200-1 000 μmol·L-1 of various heavy-metals.Cd2＋ and Zn2＋ strongly induced the siderophore production of strain ZGKD2,Ni2＋ and Mn2＋ had little effect,whereas Cu2＋ led to significant inhibition.The siderophore production of strain ZGKD2 was positively related with its metal tolerance.These results indicated that alkaline production,siderophore production,and the increase of antioxidant enzyme activities in strain ZGKD2 might be the main mechanisms of heavy-metal tolerance.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2012年第10期3613-3619,共7页
Environmental Science
基金
国家转基因生物新品种培育重大专项(2009ZX08009-130B)
国家高技术研究发展计划(863)项目(2009AA06Z320
2006AA10Z407)
中央高校基本科研业务费专项(2010YH05)
大学生创新性实验计划项目(110309z)
关键词
铜绿假单胞菌
重金属
抗氧化酶
铁载体
耐性
Pseudomonas aeruginosa
heavy metal
antioxidant enzyme
siderophore
tolerance
