No abstract

Dung beetles are exposed to a complex microbiological ecosystem during their life cycle. Characterization of novel host-defense peptides (HDP) is essential to understanding the host innate immune response in insects. It constitutes a promising alternative to look for new therapeutic agents against pathogenic microbes. We identified four new HDP, Oxysterlins 1, 2, 3, and 4 from the transcriptome of the Oxysternon conspicillatum dung beetle. These HDP display a highly conserved signal peptide and a mature peptide, characterized by an overall positive charge (cationic) (pI: 10.23–11.49), a hydrophobic ratio (ΦH: 35–41), and amphipathicity. Oxysterlins 1, 2, and 3 have a linear α-helix structure, whilst Oxysterlin 4 has a mixture of both α-helix and β-sheet structures without disulfide bonds through bioinformatics prediction and circular dichroism. Oxysterlins are part of the cecropin family group in an exclusive clade related to beetle cecropins. They have predominant antimicrobial activity against Gram-negative bacteria, including multidrug resistant strains (3.12–50 μg/mL) measured by plate microdilution. Their kinetics, in a time-killing curve showed concentration-dependent bactericidal activity. Furthermore, these HDP have low toxicity against human erythrocytes (62.5–500 μg/mL) and Vero cells (250–500 μg/mL). This article describes new HDP of the cecropin family from the Oxysternon conspicillatum dung beetle, with antimicrobial activity against multidrug resistant bacteria and low toxicity.

Dengue virus is a ssRNA+ flavivirus, which produces the dengue disease in humans. Currently, no specific treatment exists. siRNAs regulate gene expression and have been used systematically to silence viral genomes; however, they require controlled release. Liposomes show favorable results encapsulating siRNA for gene silencing. The objective herein was to design and evaluate in vitro siRNAs bound to liposomes that inhibit DENV replication. siRNAs were designed against DENV1–4 from conserved regions using siDirect2.0 and Web-BLOCK-iT™ RNAiDesigner; the initial in vitro evaluation was carried out through transfection into HepG2 cells. siRNA with silencing capacity was encapsulated in liposomes composed of D-Lin-MC3-DMA, DSPC, Chol. Cytotoxicity, hemolysis, pro-inflammatory cytokine release and antiviral activity were evaluated using plaque assay and RT-qPCR. A working concentration of siRNA was established at 40 nM. siRNA1, siRNA2, siRNA3.1, and siRNA4 were encapsulated in liposomes, and their siRNA delivery through liposomes led to a statistically significant decrease in viral titers, yielded no cytotoxicity or hemolysis and did not stimulate release of pro-inflammatory cytokines. Finally, liposomes were designed with siRNA against DENV, which proved to be safe in vitro.

La pandémie de la COVID-19 a bouleversé les rapports avec autrui dans le milieu universitaire suite à la mise en place des mesures sanitaires. Cette étude a pour but de mieux comprendre la réalité vécue et verbalisée par les étudiant.e.s des 1er et 2e cycles en travail social durant la pandémie de la COVID-19 et en confinement obligatoire. L’étude couvre le volet qualitatif d’un large sondage auprès de 621 participant.e.s et comprend une recherche quantitative auprès de 90 étudiant.e.s en travail social. Les résultats montrent une perception négative des étudiant.e.s en travail social sur le plan émotionnel, en raison des enseignements en mode virtuel et d’une surcharge de travail durant cette pandémie. Les résultats de cette étude suggèrent un besoin de soutien pour les étudiant.e.s pendant les périodes de confinement, une mise en garde à propos des méthodes d’enseignement, ainsi que des préoccupations quant à la façon dont l’enseignement virtuel affecte la qualité de la formation en travail social.