Effect of heavy metals on growth response and antioxidant defense protection in Bacillus cereus

Abstract

Bacterial cells in aerobic environment generate reactive oxygen species which may lead to oxidative stress, induced by a wide range of environmental factors including heavy metals. In the present context an attempt has been made to determine the toxic impact of cadmium and copper on growth performance, oxidative stress, and relative level of antioxidant protection in Bacillus cereus. Outcome of this study suggests that both the metal ions depleted the growth rate in this organism with respect to time and concentration of the metal ions. CdCl2 exposure induced extracellular glutathione (GSH) production, whereas, its level was declined in response to CuSO4. Superoxide dismutase (SOD) activity and hydrogen peroxide (H2 O2 ) content was elevated under CdCl2 stress but the activity of catalase (CAT) was inhibited. In contrast, incubation of bacteria with CuSO4 exhibited decreased SOD activity with concomitant rise in CAT activity and H2 O2 content. We also observed elevation of intracellular GSH level in this bacteria following supplementation of N-acetyl cysteine (NAC) in the medium. Overall findings of this study indicated differential toxicity of CdCl2 and CuSO4 in inducing oxidative stress, depleting growth rate and the possible involvement of GSH and CAT in adaptive antioxidant response.

Protein profiling of metal‐resistantBacillus cereusVITSH1

“…c,d) indicated the presence of two major bands around 200 and 180 kDa in the presence of metal. The activity of catalase was found to increase when chromium concentration increased from 300 to 2000 mg l −1 (Table ) which correlates with the previous findings on copper‐resistant B. cereus (Behera et al ). Two white bands in purple background around 60–90 kDa in gel assay indicated GPX activity (Fig.…”

Copper intoxication inhibits aerobic nucleotide synthesis in Streptococcus pneumoniae

“…37 Additionally, exposure to high levels of copper have been shown to interfere with the activity of manganese-dependent SodA. 38 We found that deletion of sodA in either the TIGR4 or the Δ copA background did not significantly alter sensitivity to copper stress. (Fig.…”

Microorganismos tolerantes a metales pesados del pasivo minero Santa Rosa, Jangas (Perú)

“…Respecto a las bacterias, Cidre et al 2017 portado algunas cepas del género Serratia y Bacillus con alto nivel de resistencia a cobre, habiendo encontrado la presencia de genes pertenecientes al cluster pco multicobre oxidasa y al cluster sil involucrado en la resistencia a Cu y Ag en especies del género Serratia y otras gram negativas. Del mismo modo, Behera et al (2014) en el estudio de respuesta antioxidativa de B. cereus frente a cadmio y cobre, encontraron que ambos metales inducían diferentes respuestas, donde la respuesta frente al cobre estaría relacionada con la producción de catalasas. Así mismo, algunas cepas de B. cereus mostraron alta capacidad de biosorción de cobre (Rohini & Jayalakshme 2015, Oladipo et al 2018b, encontrándose la presencia de genes de resistencia al cobre en el cromosoma y que el grado de biosorción era dependiente a las condiciones del medio cultivo y entorno (Rohini & Jayalakshme 2015).…”