Growth and Antioxidant System of Escherichia coli in Response to Microcystin-RR

Abstract

Microcystins are a kind of cyclic hepatoxins produced by many species of cyanobacteria. The toxic effects of microcystins on animals and plants have been well studied. However, the reports about the effects of microcystins on microbial cells are very limited. In present paper, Escherichia coli was undertaken to determine the effect of microcystin-RR. These results suggested that microcystin-RR could prolong the growth of E. coli when exposed to high concentrations of microcystin-RR and cause the accumulation of ROS and induce the oxidant stress for a short time. The antioxidant system protects E. coli from oxidative damage.

Microcystin-LR does not induce alterations to transcriptomic or metabolomic profiles of a model heterotrophic bacterium

“…Previous studies have reported that exposure to MCRR or MCLR produced oxidative stress and cell envelope stress in bacteria and/or cyanobacteria [ 27 , 50 , 51 ]. In our study, no genes associated with oxidative or cell envelope stress were differentially expressed due to MCLR exposure.…”

“…Previous studies have reported that microcystin-RR generates oxidative and cell envelope stress in E . coli [ 26 , 27 , 58 ]. Based on these reports, we hypothesized that exposure to microcystin would trigger differential expression in genes that respond to oxidative and cell envelope stress and that metabolite concentrations would alter as cells respond to induced stress.…”

“…However, concentrations as high as 25 mg/L have been reported in extremely dense blooms [ 1 ]. The concentrations used in our experiments were chosen to represent the high end of an environmentally relevant range (1 mg/L) as well as a high concentration (10 mg/L) that was similar to those used in other studies [ 22 , 24 , 27 ]. This allowed our results to be more directly comparable to those of previous works.…”

“…In a separate study, Yang et al . [ 27 ] exposed E . coli to MCRR concentrations of 1, 5, 10, and 15 mg/L.…”

The permeability effect of microcystin-RR on Escherichia coli and Bacillus subtilis

“…Our previous work also showed that MC-RR has no lethal effect on E. coli and B. subtilis [29,30]. However, MC-RR could increase the sensitivity of E. coli and B. subtilis to lysozyme, which was normally excluded by the cell outer membrane of bacteria.…”