Differential toxicity of Al2O3 particles on Gram-positive and Gram-negative sediment bacterial isolates from freshwater

Bhuvaneshwari, M.; Bairoliya, Sakcham; Parashar, Abhinav; Cantiracēkaran̲, Nā.; Mukherjee, Amitava

Differential toxicity of Al2O3 particles on Gram-positive and Gram-negative sediment bacterial isolates from freshwater

2016

Bhuvaneshwari, M. | Bairoliya, Sakcham | Parashar, Abhinav | Cantiracēkaran̲, Nā. | Mukherjee, Amitava

The current study was aimed to explore the differential effects on Gram-positive and Gram-negative freshwater sediment bacterial isolates upon exposure to nano-particles and bulk particles of Al₂O₃ at low concentrations (0.25, 0.5, and 1 mg/L). The Gram-negative Pseudomonas aeruginosa was more susceptible to both the nano-forms and bulk forms than the Gram-positive Bacillus altitudinis. The generation of reactive oxygen species (ROS) and release of lipopolysaccharide due to membrane damage were dependent on the dose of nano-Al₂O₃. The Fourier transform infrared spectroscopy (FT-IR) studies confirmed the attachment of nano-Al₂O₃ on bacterial cells, which may lead to subsequent changes in the cell membrane composition and integrity. Internalization of nano-Al₂O₃ was estimated to be more for P. aeruginosa than for B. altitudinis cells. As a role of defense mechanism, the biofilm formation and production of extracellular polymeric substances (EPSs; polysaccharide and protein) were increased with respect to the concentration of toxicant. Nano-Al₂O₃ was estimated to cause more DNA damage than the bulk particles in both Gram-positive and Gram-negative bacterial strains.

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