C. elegans as a Model to Develop Anti-helmintic Strategies in Solid Waste Management
Caenorhabditis elegans is a widely used model nematode for developing anti-helmintic drugs. We have used that for developing safe waste management strategy against soil transmitted helminthes contributing most significantly to global burden of infection. Sludge accumulation is the major problem in various parts of the world. Composting can be a cost-effective solution and can be potentially augmented with inherent sewage lytic agents. To sustain the development of safe and feasible sludge management strategies, studies were undertaken to confirm the presence of hydrolytic enzymes secreted by micro-organisms of the sewage along with the associated enzymes which can be vital for treating the pathogenic helminthes of the sewage that are posing huge problems in sanitation. Sewage sludge was characterized with respect to their total protein content and hydrolytic enzyme activity. It showed amylase and chitinase activity and the compost juices of both uninoculated and inoculated samples yielding positive results for amylase, and chitinase but not protease. Protein concentration was found to be about 75μg/ml and 55μg/ml obtained after 40% and 50% saturation of ammonium sulphate. However, all three samples were positive for amylase activity. Different preparations of compost extract was tested for their antihelmintic activity by C. elegans egg hatching assay. A maximum inhibition of 57% in the uninoculated samples and 50% in the samples inoculated with both A. niger and T. viride was observed for 1/100th of dilution.
Efficiency of lytic enzymes in treating sludge can also be enhanced by the activity of some biocompatible compounds like phytochemicals which can augment the anti-helminthic effects of sewage proteins and heterogenous compost juices that exhibited positive hydrolytic activity. In our study, we used compounds like Benzyl isothicyanate (BITC), Cinnamic acid, Gallic acid, MEK extracts of Berberis tinctoria and Quercetin to screen for their potential anti-helminthic activity by treating them against the eggs of Caenorhabditis elegans. These compounds were treated in combination to establish results of the synergistic effect of these compounds. The effect of these phytochemicals against mature as well as immature eggs was also studied to examine differences in their susceptibility patterns. Our results show that BITC exhibited the highest inhibitory effect i.e. right from 20µM concentration, on the eggs showing great potential as an anti-helminthic strategy that can be combined with sewage and composting for safer sanitation solutions.