摘要
Six samples containing extremely high concen-tration of Pb,Zn,and Cd were obtained from the layers of 5−10 cm and 25−30 cm three tailing piles,with ages of about 10,20 and more than 80 years,respectively.Then,48 bacterial strains were obtained from these samples,and sub-sequently their phylogenetic positions were determined by analysis on the partial sequence of 16S rRNA gene(fragment length ranging from 474 to 708 bp).These isolates were members of the Arthrobacter genus,phylogenetically close to A.keyseri and A.ureafaciens,with sequence ranging from 99.1%to 100%.Furthermore,genetic variation between sub-populations from different samples was revealed by analysis on their randomly amplified polymorphic DNA profile.Nei genetic distance showed that the greatest differentiation occurred between subpopulation A and C.Notably,either genetic distance between subpopulations from the layers of 5−10 cm and 25−30 cm of each tailing pile or between same layers of different tailing pile increased with the history of tailings.Moreover,correlation analysis showed that soluble Pb has a significantly negative relationship with Nei’gene diversity of subpopulation.It was assumed that soluble Pb may be respon-sible for the reduced genetic diversity of the Arthrobacter popu-lation.Our data provided evidence that genetic differentiation of microbial populations was consistent with the changes of environmental factors,particularly heavy metals.
基金
This study was funded by the Natural Science Foundations of Yunnan Province,China(No.2002C0001Q)
the Nationa l Natural Science Foundation of China(Grant No.30360003).
