Lloyd-Jones G, Ritchie D A, Strike P
Department of Genetics and Microbiology, Donnan Laboratories, University of Liverpool, U.K.
FEMS Microbiol Lett. 1991 Jun 1;65(1):19-24. doi: 10.1016/0378-1097(91)90464-l.
Escherichia coli AB1157, and the transconjugant AB1157 (pMJ600), were used to study the mechanism of tellurite resistance conferred by pMJ600, which contains the tellurite resistance determinant cloned from the IncHI-2 conjugative plasmid pMER610. The transconjugant can tolerate a 100-fold higher concentration of potassium tellurite [K2TeO3] than the plasmid-free strain. Both strains were found to accumulate tellurite irreversibly at equivalent rates, with elemental tellurium being deposited intracellularly, direct efflux of tellurite was not found to contribute to the resistance mechanism. However, under these conditions, growth, protein synthesis and oxygen uptake ceased in AB1157, but-were unaffected in the transconjugant. No NADH- or NADPH-linked reduction of tellurite was detected in crude cell extracts of either strain; however, cell extracts of both reduced tellurite at alkaline pH in the absence of any co-factors.
大肠杆菌AB1157和转接合子AB1157（pMJ600）用于研究pMJ600赋予亚碲酸盐抗性的机制，pMJ600含有从IncHI-2接合质粒pMER610克隆的亚碲酸盐抗性决定簇。转接合子能够耐受比亚碲酸钾[K2TeO3]无质粒菌株高100倍的浓度。发现两种菌株以相同速率不可逆地积累亚碲酸盐，元素碲沉积在细胞内，未发现亚碲酸盐的直接外排有助于抗性机制。然而，在这些条件下，AB1157中的生长、蛋白质合成和氧气摄取停止，但转接合子未受影响。在两种菌株的粗细胞提取物中均未检测到与NADH或NADPH相关的亚碲酸盐还原；然而，在没有任何辅因子的情况下，两种菌株的细胞提取物在碱性pH下均能还原亚碲酸盐。
