Turpeinen Riina, Kairesalo Timo, Häggblom Max M
Department of Ecological and Environmental Sciences, University of Helsinki, Lahti, Finland.
FEMS Microbiol Ecol. 2004 Jan 1;47(1):39-50. doi: 10.1016/S0168-6496(03)00232-0.
Microbial community structure, potential microbial activity and As resistance were affected by arsenic (As), chromium (Cr) and copper (Cu) contamination in soils of abandoned wood impregnating plants. Contaminated soils differed in the concentrations of soil acid-soluble and total water-soluble As, Cr and Cu, and in the concentration of bioavailable As analyzed with a bacterial sensor. Phospholipid fatty acid (PLFA) and 16S rRNA gene terminal restriction fragment length polymorphism (t-RFLP) profiles indicated that exposure to high metal contamination or subsequent effects of this exposure permanently changed microbial community structure. The total number of colony forming units (CFU) was not affected by metal contamination and the As(V)-resistant bacterial ratio to total heterotrophic plate counts was high (0.5-1.1) and relatively independent of the concentration of As. In contrast, the proportion of As(III)-resistant bacteria was dependent on the concentration of As in the soils and a significant positive relationship was found between the bioavailability of As and the proportion of As(III)-resistant bacteria. Dominant As-resistant isolates from contaminated soils were identified by their fatty acid methyl ester (FAME) profiles as Acinetobacter, Edwardsiella, Enterobacter, Pseudomonas, Salmonella and Serratia species. No differences were noted in glucose mineralization among contaminated and control soil samples within sites. Based on [(14)C]glucose mineralization the community was able to compensate for the reduced diversity. According to t-RFLP results, this was not due to a reversion towards the unexposed community, but mainly due to the appearance of new dominating species. This study, combining complementary culture-dependent and -independent methods, suggests that microbes are able to respond to soil metal contamination and maintain metabolic activity apparently through changes in microbial community structure and selection for resistance.
废弃木材浸渍厂土壤中的砷（As）、铬（Cr）和铜（Cu）污染会影响微生物群落结构、潜在微生物活性及对砷的抗性。受污染土壤中酸溶性和总水溶性As、Cr和Cu的浓度以及用细菌传感器分析的生物可利用性As的浓度各不相同。磷脂脂肪酸（PLFA）和16S rRNA基因末端限制性片段长度多态性（t-RFLP）分析结果表明，暴露于高金属污染或这种暴露的后续影响会永久性改变微生物群落结构。菌落形成单位（CFU）总数不受金属污染影响，抗As（V）细菌占总异养平板计数的比例较高（0.5 - 1.1），且相对独立于As浓度。相比之下，抗As（III）细菌的比例取决于土壤中As的浓度，并且发现As的生物可利用性与抗As（III）细菌的比例之间存在显著正相关。通过脂肪酸甲酯（FAME）分析，从受污染土壤中分离出的主要抗As菌株被鉴定为不动杆菌属、爱德华氏菌属、肠杆菌属、假单胞菌属、沙门氏菌属和沙雷氏菌属。各采样点受污染土壤样品和对照土壤样品之间的葡萄糖矿化情况没有差异。基于[（14）C]葡萄糖矿化，群落能够弥补多样性的降低。根据t-RFLP结果，这并非由于向未暴露群落的逆转，而是主要由于新的优势物种的出现。本研究结合了互补的培养依赖性和非依赖性方法，表明微生物能够对土壤金属污染做出反应，并显然通过微生物群落结构的变化和对抗性的选择来维持代谢活性。
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