Facilitating the gut brain axis by probiotic bacteria to modulate neuroimmune response on lead exposed zebra fish models

Unravelling the efficacy of gut biome has a major impact on health. An unbalanced microbiome composition is linked to many common illnesses such as gut dysbiosis, mental deformities and immunological imbalance. An optimistic influence on the gut biome can be made by consumingprobiotics. This would stimulate neuroprotection and immunomodulation intended by heavy metals pollution. Lead is a major source of neurotoxin that can induce neural deformities. Lactobacillusspecies isolated from curd were characterized to confirm its specificity. Zebra fish was reared at standard conditions and preclinical assessment on the intensity of induced neurotoxin lead was performed. The embryo toxic assay, immunomodulation effects and animal behavioural models endorsed the consequence of neurotoxicity. Different concentrations of bacterial isolate with standard antidepressant was considered for analysing the vigour of toxicity and its influence on cognitive behaviour by novel tank diving method. The restrain in the animal behaviour was also conferred by all the test samples with a decreased bottom dwelling time which was authenticated with haematology and histopathological studies. The alterations in morphology of the lymphocytes were balanced by the treated test samples. This study paves a twofold potential of probiotic as neuroprotectant and immune modulator against heavy metal toxicity.

Functional Properties of Heavy Metal Tolerant Probiotic Strains Isolated from Curd

The two heavy metal tolerant bacterial isolates L. fermentum SN_4 and L. rhamnosus SN_6 were identified (isolated from curd samples) which were found to be potentially resistant to Cr6+, Pb2+ and Cd2+ under study. Both the isolates were resistant to simulated gastric juices at pH 2.0 and 3.0 at 0 hours and survived well more than 50% in 0.2%, 0.3%, 0.5% and 1.0% bile salt solution but the isolate L. rhamnosus SN_6 showed the best survival at all the concentrations of bile salt. These two isolates showed poor antagonistic agent activity against the four pathogenic bacteria viz. E. coli, B. cereus, S. typhimurium and V. cholera. L. fermentum SN_4 showed resistant to all antibiotic except clindamycin and azithromycin, on the other hand, L. rhamnosus SN_6 was found resistant to clindamycin and tetracycline only. Also, they were found to be haemolytic negative which proved them to be a potential probiotic.