期刊名称：Journal of Applied Sciences in Environmental Sanitation
印刷版ISSN：0126-2807
电子版ISSN：1978-6980
出版年度：2011
卷号：6
期号：2
页码：201-211
出版社：Sepuluh Nopember Institute of Technology (ITS)
摘要：In the present study, with the intention of screening for heavy metaltolerance, a number of bacteria were isolated and characterized from an Egyptian soil. Three Gram positive isolates were identified as Staphylococcus aureus, Bacillus subtilis, Bacillus cereus and two Gram negative isolates were identified as Pseudomonas sp. and Bordetella sp. Both Gram positive and Gram negative bacteria showed the metal tolerance against Cd2+and Co2+at different concentrations ranging from 0.0 1.0 mg L1.Metals tolerance in all bacteria showed the higher sensitivity to Cd2+more than Co2+. The semi quantitative reverse transcription PCR (RT PCR) was used to investigate the gene expression mechanism responsible for the metal resistance in some of these gram positive and gram negative bacteria that were, highly resistant to Co2+and Cd2+. The mer, chr, czc, and ncc genes that are responsible for resistance to heavy metals, were shown to be present in these bacteria by using RT PCR. The results of the gene expression analysis revealed that merA and chrB genes were down regulated in the all stain of bacteria (Staphylococcus. aureus, Bacillus subtilis, Bacillus cereus, Pseudomonas sp and Bordetella sp.) treated with Co2+and Cd2+. However, cobalt zinc cadmium (czcD) and nickel cobalt cadmium (nccA) gene were up regulated in the all stain of bacteria treated with Co2+and Cd2+. Therefore, Co2+and Cd2+resistance genes are widely distributed in both gram positive and gram negative isolates obtained from different samples of Egyptian soils
关键词：Heavy metals; Egyptian soil; bacteria; RT PCR; metal resistance genes
