TmPGRP-SA regulates Antimicrobial Response to Bacteria and Fungi in the Fat Body and Gut of Tenebrio molitor

Antimicrobial immune response is mediated by a signal-transducing sensor, peptidoglycan recognition protein-SA (PGRP-SA), that can recognize non-self molecules. Although several studies have focused on the involvement of Drosophila PGRP-SA in antimicrobial peptide (AMP) expression in response to infections, studies on its role in Tenebrio molitor are lacking. Here, we present a functional analysis of T. molitor PGRP-SA (TmPGRP-SA). In the absence of microbes, TmPGRP-SA was highly expressed in the late-larval fat body, followed by hemocytes, and gut. Interestingly, following Escherichia coli, Staphylococcus aureus, and Candida albicans infections, the mRNA level of TmPGRP-SA was significantly upregulated in both the fat body and gut. TmPGRP-SA silencing had a significant effect on the mortality rates for all the microbes tested. Moreover, TmPGRP-SA is required for regulating the expression of eight AMP genes namely TmTenecin-1, -2, and -4; TmDefensin-1 and -2; TmColeoptericin-1; and TmAttacin-1b and -2 in the fat body in response to E. coli and S. aureus infections. TmPGRP-SA is essential for the transcription of TmTenecin-2, -4; TmDefensin-2; TmColeoptericin-1, -2; and TmAttacin-1a, -1b, and -2 in the gut upon E. coli and C. albicans infections. However, TmPGRP-SA does not regulate AMP expression in the hemocytes. Additionally, TmDorsal isoform X2, a downstream Toll transcription factor, was downregulated in TmPGRP-SA-silenced larval fat body following E. coli and S. aureus challenges, and in the gut following E. coli and C. albicans challenges.

Certain Biochemical Changes in Haemolymph of Eri Silkworm, Samia Cynthia Ricini after Inoculation with Bacteria

The insect immune system exists to protect the host from pathogenic invaders and from other harmful insults. Upon bacterial infection insect haemolymph may lead to fatal consequences and it plays a most important role in transport and storage of nutrients, amino acids and free amino acids concentrations are marked changes for substrates by the immune system, these substrates are provide energy and precursors for the synthesis of new cells, effecter molecules, and protective molecule. We have been studied the certain biochemical changes in bacterial challenged Eri silkworm haemolymph at various time intervals. Results shows that the proteins and amino acids levels were significantly elevated and 18 individual free amino acids were found and that are quantitatively variation in the haemolymph after challenge with gram –ve and gram +ve bacteria when compared and control and sterile haemolymph. We may conclude that these were directly involved in the antimicrobial immune response of Eri silkworm innate immunityInt J Appl Sci Biotechnol, Vol 3(2): 236-242 DOI: http://dx.doi.org/10.3126/ijasbt.v3i2.12453