Lactobacillus casei stimulates phase-II detoxification system and rescues malathion-induced physiological impairments in Caenorhabditis elegans

Malathion, an organophosphorus insecticide, is renowned for its inhibitory action on acetylcholinesterase (AChE) enzyme that eventually leads to widespread disturbance in the normal physiological and behavioral activities of any organism. Lactic acid bacteria (LAB) are still an underexploited and inexhaustible source of significant pharmaceutical thrust. In the present study, Caenorhabditis elegans was employed to identify and characterize the indigenous LAB isolated from different traditional food against malathion-induced toxicity. The results demonstrated that malathion at its LD50 concentration decreased various C. elegans physiological parameters such as survival, feeding, and locomotion. Among the screened isolates, L. casei exhibited an excellent protective efficacy against malathion-induced toxicity by increasing the level of AChE and thereby rescued all physiological parameters of C. elegans. In addition, short-term exposure and food choice assay divulged that L. casei could serve as a better food to protect C. elegans from noxious environment. The expression analysis unveiled that L. casei gavage upregulated the phase-II detoxification enzymes coding genes metallothioneins (mtl-1 and mtl-2) and glutathione-S-transferase (gst-8) and thereby eliminated malathion from the host system. Furthermore, the upregulation of ace-3 along with down-regulation of cyp35a in the nematodes supplemented with L. casei could be attributed to attenuate the malathion-induced physiological defects in C. elegans. Thus, the present study reports that an indigenous LAB-L. casei could serve as a promising protective agent against the harmful effects of pesticide.