Antimicrobial potential of a ponericin-like peptide isolated from Bombyx mori L. hemolymph in response to Pseudomonas aeruginosa infection

Abstract

The main effectors in the innate immune system of Bombyx mori L. are antimicrobial peptides (AMPs). Here, we infected B. mori with varied inoculum sizes of Pseudomonas aeruginosa ATCC 25668 cells to investigate changes in morpho-anatomical responses, physiological processes and AMP production. Ultraviolet-visible spectra revealed a sharp change in λ max from 278 to 285 nm (bathochromic shift) in the hemolymph of infected B. mori incubated for 24 h. Further, Fourier Transform InfraRed studies on the hemolymph extracted from the infected B. mori showed a peak at 1550 cm −1 , indicating the presence of α-helical peptides. The peptide fraction was obtained through methanol, acetic acid and water mixture (90:1:9) extraction, followed by peptide purification using Reverse Phase High Performance Liquid Chromatography. The fraction exhibiting antibacterial properties was collected and characterized by Matrix-Assisted Laser Desorption/Ionization-Time of Flight. A linear α-helical peptide with flexible termini (LLKELWTKMKGAGKAVLGKIKGLL) was found, corresponding to a previously described peptide from ant venom and here denominated as Bm-ponericin-L1. The antibacterial activity of Bm-ponericin-L1 was determined against ESKAPE pathogens. Scanning electron microscopy confirmed the membrane disruption potential of Bm-ponericin-L1. Moreover,

Understanding Insect-microbe Interactions for Sustainable Pest Management

“…Insect defensins isolated from various insect orders including Coleoptera, Diptera, Hemiptera, Lepidoptera, Hymenoptera, and Trichoptera selectively target grampositive bacteria (Wu et al, 2018). Silkworm AMPs including cecropins, defensins, moricins, gloverins, lebocins and attacins exhibit antimicrobial activity against a broad range of bacteria, such as Klebsiella (Nesa et al, 2022).…”

Development of Aptamer-Functionalized Gold Nanoparticles as Probes in Point-of-Care Diagnostic Device for Rapid Detection of Multidrug-Resistant Bacteria in Bombyx mori L.

“…Multiple fields of vision were viewed at different magnifications. 35 Hemocompatibility of Au NPs. The hemocompatibility of the Au NPs was evaluated through a hemolytic assay.…”

“…The hemocompatibility of the Au NPs was evaluated through a hemolytic assay. 35 A diluted solution of bovine red blood cells (RBCs, 0.2 mL) was mixed with the Au NPs at 100 ppm and incubated for 2 h at ambient temperature. The absorbance of the supernatant was measured at 541 nm via a UV−vis spectrophotometer (Labman, LMSP-UV1900), and the % hemolysis was calculated using the following equation:…”

“…The SEM micrographs of freshly grown isolates (RAM2 and RAC1) were captured following the protocol described previously in the earlier section. 35 Antimicrobial Susceptibility Testing. A Kirby−Bauer disc diffusion test was conducted to examine the antibiogram profiles of the isolated RAM2 and RAC1.…”