Analysis of a novel antibacterial protein, Noduler that is conserved in insects and mammals. Asha Minz, Javaregowda Nagaraju. Laboratory of Molecular Genetics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Andhra Pradesh, India.

   In the absence of adaptive immunity, insects have acquired a powerful innate immune mechanism. Innate immune system acts as a primary defense mechanism in detecting microorganisms that aid in eliciting a plethora of antimicrobial responses in an organism. This phenomenon is marked by cellular and humoral responses leading to synthesis of effector molecules as antimicrobial peptides. A striking similarity between insect and mammalian innate immunity being constantly supported by several reported investigations. In our study, we have identified a novel antimicrobial peptide Noduler in the wild silkmoth that belong to one of the largest orders of insect, Lepidoptera, which includes various economically important insects. In silico predictions led to the finding of its orthologues in other insects and mammals. Several infection experiments and expression studies were carried out in Bombyx mori larval fat body, Drosophila adult flies and THP-1 macrophagic cells. The results suggest that the orthologues of Noduler are upregulated upon microbial challenge in a time course manner. The knockdown of these orthologues results in rendering these organisms highly susceptible to infection, suggesting the genes role in host defence in insects and mammals. These results approve the evolutionary conservation of innate immune mechanisms among species.