Relationship Between the Persistence of mer Operon Sequences in Escherichia coli and Their Resistance to Mercury |
| |
Authors: | Imtiyaz Murtaza Amit Dutt Arif Ali |
| |
Institution: | (1) Gene Expression Laboratory, Department of Biosciences, Jamia Millia Islamia, New Delhi-110 025, India, IN |
| |
Abstract: | Studies related to geographic distribution of E. coli carrying mer operon sequences were carried out on the Indian subcontinent. Out of the 80 E. coli isolates, collected from five geographically distinct regions of India, 68 were found to be resistant to one or the other
heavy metal used in the study. Among these isolates, 36 were found to be resistant to the inorganic form (HgCl2) and only 5 to resist both the inorganic and organic forms of mercury. Colony hybridization studies revealed 35 isolates
out of 68 to hybridize with the probe. Interestingly, some of the mercury-sensitive isolates (Hgs), especially from the Dal Lake, were found positive in hybridization studies. These findings, supported by mercury volatilization
studies, indicate the presence of nonfunctional/vestigial mer sequences in the isolates collected from different environments. On the other hand, few of the mercury-resistant isolates
(Hgr) from the Yamuna River did not show any sign of hybridization. Further, volatilization studies also indicated an alternate
mode of resistance mechanism operating in them. The studies demonstrate that the mer operon sequences share very high homology among the E. coli isolates collected from different geographical locations, and this metal resistance may be a genetic character that arose
from a common ancestral background.
Received: 25 May 2001 / Accepted: 27 June 2001 |
| |
Keywords: | |
本文献已被 PubMed SpringerLink 等数据库收录! |
|