Comparison of 2,4-dichlorophenoxyacetic acid degradation and plasmid transfer in soil resulting from bioaugmentation with two different pJP4 donors
Comparison of 2,4-dichlorophenoxyacetic acid degradation and plasmid transfer in soil resulting from bioaugmentation with two different pJP4 donors
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DOI：
10.1128/aem.66.8.3399-3407.2000
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发表时间：
2000-08-01
影响因子：
4.4
通讯作者：
Pepper, IL
中科院分区：
文献类型：
--
作者：
Newby, DT;Gentry, TJ;Pepper, IL
为了评价两种携带pJP4质粒的微生物的生物强化效果，进行了一项中试研究，这两种微生物分别是自然宿主Ralstonia eutroa JMP134和实验室产生的可供体反选择的菌株Eschericia coliD11，其中Re-eutroa菌株含有2，4-二氯苯氧乙酸(2，4-D)矿化所必需的染色体基因，而E.Coli菌株则没有。土壤系统受到污染，其中2，4-D单独污染或与2，4-D抗Cd共污染。在长达63天的生物反应器中，对原住民的质粒转移、质粒在土壤中的持久性和2，4-D的降解进行了监测。为了评估污染物再暴露的影响，用额外的2，4-D对一等份的生物反应器土壤进行了重新修饰。这两个引入的供体都是可培养的，并将pJP4转移到土著受体，尽管在不同程度上，分离的转接子是Burkholderia和Ralstonia属的成员？在第二次接触2，4-D时，观察到了所有处理的降解增强，这表明微生物对2，4-D的适应。在再暴露时，接种E，coliD11的处理降解最快。Cd对2，4-D的降解或接合体的形成没有显著影响，这项研究表明，供体微生物的选择可能是生物增强努力的一个关键因素，此外，在有可能再次暴露或长期污染的地点建立一系列稳定的本土质粒宿主可能特别有用。
A pilot field study was conducted to assess the impact of bioaugmentation with two plasmid pJP4-bearing microorganisms: the natural host, Ralstonia eutropha JMP134, and a laboratory-generated strain amenable to donor counterselection, Escherichia coli D11, The R. eutropha strain contained chromosomal genes necessary for mineralization of 2,4-dichlorophenoxyacetic acid (2,4-D), while the E. coli strain did not. The soil system was contaminated,vith 2,4-D alone or was cocontaminated with 2,4-D anti Cd. Plasmid transfer to indigenous populations, plasmid persistence in soil, and degradation of 2,4-D were monitored over a 63-day period in the bioreactors. To assess the impact of contaminant reexposure, aliquots of bioreactor soil were reamended with additional 2,4-D. Both introduced donors remained culturable and transferred plasmid pJP4 to indigenous recipients, although to different extents, Isolated transconjugants were members of the Burkholderia and Ralstonia genera? suggesting multiple, if not successive, plasmid transfers, Upon a second exposure to 2,4-D, enhanced degradation was observed for all treatments, suggesting microbial adaptation to 2,4-D. Upon reexposure, degradation was most rapid for the E, coli D11-inoculated treatments. Cd did not significantly impact 2,4-D degradation or transconjugant formation, This study demonstrated that the choice of donor microorganism might be a key factor to consider for bioaugmentation efforts, In addition, the establishment of an array of stable indigenous plasmid hosts at sites with potential for reexposure or long-term contamination may be particularly useful.