Response of growth and superoxide dismutase to enhanced arsenic in two Bacillus species

Abstract

Species differences in inorganic arsenic tolerance were investigated by comparing the responses of Bacillus subtilis (B. subtilis) and Bacillus thuringiensis (B. thuringiensis) to elevated concentrations of As(III) and As(V). The cell densities in treatments were always lower during the experiment compared to controls, with the exception of exposure to 1.0 mg As(V) l(-1) on the first day. It was also found that relative growth rate (RGR) of B. thuringiensis was lower than that of B. subtilis. Furthermore, RGR of each Bacillus species was negative correlation with toxicity of inorganic arsenic. However, total cell number still increased in each treatment according to cell density and RGR assays. Superoxide dismutase (SOD) activity of both Bacillus species was promoted by As(III) and As(V), especially under high arsenic concentration condition. In addition, SOD activity of B. thuringiensis was higher than that of B. subtilis during the same exposure time. In lipid peroxidation assay, thiobarbituric acid-reactive substances (TBARS) content of each Bacillus species had a significant increase with increment of arsenic concentration. Moreover, significant difference was observed between the two Bacillus species under high arsenic concentration. TBARS content of B. thuringiensis was higher than that of B. subtilis, indicating that effect of arsenic on cell membranes of B. thuringiensis was much more than that of B. subtilis. These results suggest that the two Bacillus species could adapt and live in high arsenic aquifers, although their growth and cell membranes were affected by As treatment in a way.

Comparative response of SOD in different plants against cadmium and drought stress at the molecular level

“…The phylogenetic analysis is the reliable method to explore the insight of molecular evolution pattern of SOD through comparing the sequences of different types of SOD genes in different species or the same species considering the positions and numbers of introns and exons, and the sequences of SOD amino acid residues (Xie et al, 2014). In the present study, a homology search for SOD genes sequences in A. thaliana, S. lycopersicum, T. aestivum, and O. sativa was performed to identify the SOD isogenes by using T-BLAST search.…”

“…Predominantly, plants initialize a complex and systematic defense mechanism to safeguard themselves from detrimental effects caused by abiotic stress. Superoxide dismutase (SOD, EC 1.15.1.1) is a crucial enzyme functioning as the first line of defense against ROS in plant cells by virtue of its ability to convert superoxide radicals (O •− 2 ) into hydrogen peroxide (H 2 O 2 ) (Xie et al, 2014;Lightfoot et al, 2017), thereby maintaining cell membrane stability and minimizing O •− 2 attack. SOD isoenzymes are usually induced by their metal co-factors such as Cu/Zn, Fe, and Mn, which endure in all subcellular organelles ( Figure 1).…”

Application of BCXZM Composite for Arsenic Removal: EPS Production, Biotransformation and Immobilization of Bacillus XZM on Corn Cobs Biochar

“…The arsenic-transforming and EPS-producing indigenous strain Bacillus XZM (SUB4899103 BacillusMK271736) was isolated from the deep ground water of Shuangzhai village Dotong Basin, Shanxi, China (39°21′ N, 112°51′ S), as a part of our previously reported work. It can tolerate high arsenic concentrations and carryout redox transformations, which are required for arsenic bioremediation [ 29 ]. The strain was acclimatized to 50 ppm As(V) in nutrient broth (NB) media (0.5% peptone, 0.2% yeast extract and 0.5% NaCl) at 32 °C overnight prior to BCXZM preparation.…”