Antibacterial properties of lucifensin in Lucilia sericata maggots after septic injury

Objective:To investigate the antibacterial properties of lucifensin in maggots of IjicUia sericala after septic injury.Mettiods:In our preliminary study we have shown that injuring the maggots with a needle soaked in lipopolysaccharide solution induced within 24 h lucifensin expression in the fat body and in the grease coupler of the salivary glands.It is assumed that lucifensin is secreted solely from this tissue into the haemoiymph(similar to other insect defensins) and not into secreted/excreted products.We used high-performance liquid chromatography fractionation and radial diffusion assay to investigate the antibacterial properties of haemoiymph extracted from larvae after septic injury.Results:After septic injury,production of lucifensin in the haemoiymph is increased.This led to higher antibacterial activity of such haemoiymph in comparison to non-stimulated larvae.Coclusions:These results suggest that beside the previously demonstrated role of lucifensin in the debridement therapy,lucifensin is simultaneously important as a part of the systematic immune response.

Peptidomic analysis of Chinese shrimp(Fenneropenaeus chinensis) hemolymph by magnetic bead-based MALDITOF MS

Peptides in shrimp hemolymph play an important role in the innate immune response.Analysis of hemolymph will help to detect and identify potential novel biomarkers of microbial infection.We used magnetic bead-based purification(ClinProt system) and matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF MS) to characterize shrimp hemolymph peptides.Shrimp serum and plasma were used as the source of samples for comparative analysis,and it was found that serum was more suitable for shrimp hemolymph peptidomic analysis.To screen potential specific biomarkers in serum of immune-challenged shrimps,we applied magnetic bead-based MALDI-TOF MS to serum samples from 10 immune-challenged and 10 healthy shrimps.The spectra were analyzed using FlexAnalysis 3.0 and ClinProTools 2.1 software.Thirteen peptide peaks significantly different between the two groups were selected as candidate biomarkers of lipopolysaccharide(LPS)-infection.The diagnostic model established by genetic algorithm using five of these peaks was able to discriminate LPS-challenged shrimps from healthy control shrimps with a sensitivity of 90% and a specificity of 100%.Our approach in MALDITOF MS-based peptidomics is a powerful tool for screening bioactive peptides or biomarkers derived from hemolymph,and will help to enable a better understanding of the innate immune response of shrimps.