Effect of carbaryl on enzyme activities in Escherichia coli and soil isolate- Pseudomonas aeruginosa

Carbamate insecticide, carbaryl (1-naphthyl-Nmethylcarbamate), is highly toxic with a wide range of activity and known to be metabolized by microorganisms belonging to a variety of bacterial genera by interacting with different components. To evaluate its toxicity, the present study was undertaken by using increasing concentrations of carbaryl (10-8 to 10-2M) and evaluated for its toxicity to Escherichia coli with emphasis on enzyme assays such as such as activities of amylase, protease, phosphatase, superoxide dismutase (SOD), catalase and peroxidase assay and was further compared to the soil isolate- Pseudomonas aeruginosa at a given periods of 24 to 72 hrs respectively. The results indicated that carbaryl treated groups exhibited a significant (P ≤ 0.05) increase in the enzyme activities of Escherichia coli and Pseudomonas aeruginosa with an increase in dose and duration when compared to the controls. While, in assessment with its free corresponding, the activity was less in immobilized Escherichia coli cells enlightening that immobilized system is less responsive to carbaryl. Present study suggested that carbaryl is a toxicant affecting the synthesis of enzyme activities in of Escherichia coli and Pseudomonas aeruginosa and alteration in these enzymes occurs as an adaptive mechanism to chemical stress or participation of these enzymes in the protection against ROS, thereby impairing the physiological and metabolic activities of the cell.