LAUSR

The toxic effect of Nickel (Ni (II)) on humans and animals has been previously addressed. Owing to the important application of psychrotolerant bacteria in Ni (II) damage remediation in contamination sites at low temperatures, the response mechanism of psychrotolerant bacteria to Ni (II) toxicity must be elucidated. Therefore, the effect of Ni (II) toxicity on a psychrotolerant Bacillus cereus D2 was studied, showing a way to alleviate the Ni (II) toxicity in strain D2. The results showed that strain D2 growth was completely inhibited at a concentration of 100 mg/L of Ni (II). The main effects of Ni (II) toxicity on strain D2 were membrane damage and reactive oxygen species-dependent oxidative stress. Additionally, Ni (II) toxicity resulted in dysregulation of the cell cycle in strain D2. Furthermore, metabolomic analysis showed that the biosynthesis of amino acids and ABC transporters were significantly affected, and the relative abundance of seven important amino acids changed in a concentration-dependent manner. Addition of 20 mM or 5 mM amino acids to 100 mg/L Ni (II)-treated strain D2 restored its growth. This study provides insights into the way to alleviate the Ni (II) toxicity in strain D2, thus contributing to the development of bioremediation strategies.