CHARACTERIZATION OF ANTI-HELICOBACTER PYLORI PEPTIDES PRESENT IN THE HEMOLYMPH OF HERMETIA ILLUCENS LARVAE

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Analogous peptides acting on different pathways: a comparative study of Bicarinalin and U9-MYRTX-Tb1a from an ant venom

Conference exclusively online.International audienc

Analogous peptides acting on different pathways: a comparative study of Bicarinalin and U9-MYRTX-Tb1a from an ant venom

Conference exclusively online.International audienc

New 3-substituted-2,1-benzisoxazoles: Synthesis and antimicrobial activities

International audienceA new series of 3-substituted-2,1-benzisoxazoles (anthranils) were prepared by different methods and characterized by spectroscopic methods and mass spectrometry. These 2,1-benzisox-azoles were tested in vitro for their antiplasmodial activity on a chloroquine-resistant strain of Plasmodium falciparum (P.f.) (FcB1), and for antimicrobial activity against representative bacterial and fungal strains, as well as for cytotoxicity on MCF7 human breast cancer cells. Given the log P calc and selectivity index values (cytotoxicity/antiplasmodial activity ratio), the benzo[c]isoxazol-3-ylmethylene-phenyl-amine (11) (imino-benzisoxazole) was identified as the best hit against P.f. (FcB1), and the benzo[c]isoxazol-3-yl-phenyl-methanone (3) (3-acyl-2,1-benzisoxazole) against P.f. and the Geotrichum candidum fungal strain

Potent bactericidal effects of bicarinalin against strains of the Enterobacter and Cronobacter genera

International audienceBicarinalin is a linear and C-terminus amidated cationic peptide characterized from the Tetramorium bicarinatum ant venom. In the present study, the antibacterial activity of bicarinalin against four representative strains of Enterobacter genus and Cronobacter sakazakii, emerging opportunistic pathogens in foods, was evaluated in laboratory conditions. The lowest minimal inhibitory and minimal bactericidal concentrations were obtained on C. sakazakii, while the highest values were found on Enterobacter cloacae. Whatever the microorganism, bicarinalin was more potent than melittin, ampicillin and tetracycline. SYTOX green nucleic acid staining was used to assess the effect of bicarinalin on bacterial membrane integrity. In all strains, permeabilization of the membrane was observed for sub-MIC values, indicating that bicarinalin efficiently disrupted the plasma membrane leading to the bacterial death. Collectively, these data suggest that this natural peptide could be used for enhancing the microbial safety of food and prevent the microbial spoilage of diverse biological matrices by Enterobacteriaceae

Antioxidant and Antimicrobial Activities of <i>Erodium arborescens</i> Aerial Part Extracts and Characterization by LC-HESI-MS² of Its Acetone Extract

The phytochemical analysis of antioxidant and antibacterial activities of Erodium arborescens aerial part extracts constitute the focus of this research. The chemical composition of an acetone extract was investigated using LC-HESI-MS2, which revealed the presence of 70 compounds. The major identified components were tannin derivatives. Total polyphenol and total flavonoid contents were assessed in plant extracts (hexane, ethyl acetate, acetone and methanol). The results showed that the acetone extract exhibited the highest contents of polyphenols and flavonoids, 895.54 and 36.39 mg QE/g DE, respectively. Furthermore, when compared to other extracts, Erodium arborescens acetone extract was endowed with the highest antioxidant activity with 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and total antioxidant capacity (TAC) tests. In addition, the four extracts of Erodium arborescens showed variable degrees of antimicrobial activity against the tested strains, and the interesting activity was obtained with acetone and methanol extracts

Deciphering the Molecular Diversity of an Ant Venom Peptidome through a Venomics Approach

International audienceThe peptide toxins in the venoms of small invertebrates such as stinging ants have rarely been studied due to the limited amount of venom available per individual. We used a venomics strategy to identify the molecular diversity of the venom peptidome for the myrmicine ant Tetramorium bicarinatum. The methodology included (i) peptidomics, in which the venom peptides are sequenced through a de novo mass spectrometry approach or Edman degradation; (ii) transcriptomics, based on RT-PCR-cloning and DNA sequencing; and (iii) the data mining of the RNA-seq in the available transcriptome. Mass spectrometry analysis revealed about 2800 peptides in the venom. However, the de novo sequencing suggested that most of these peptides arose from processing or the artifactual fragmentations of full-length mature peptides. These peptides, called "myrmicitoxins", are produced by a limited number of genes. Thirty-seven peptide precursors were identified and classified into three superfamilies. These precursors are related to pilosulin, secapin or are new ant venom prepro-peptides. The mature myrmicitoxins display sequence homologies with antimicrobial, cytolytic and neurotoxic peptides. The venomics strategy enabled several post-translational modifications in some peptides such as O-glycosylation to be identified. This study provides novel insights into the molecular diversity and evolution of ant venoms

Pharmacokinetic and antimicrobial activity of a new carvacrol-based product against a human pathogen, Campylobacter jejuni

International audienceAIM: In vitro and in vivo studies were conducted to test a new carvacrol-based product designed to delay the carvacrol release so that it could reach the caeca of broiler chickens in order to control Campylobacter jejuni.METHODS AND RESULTS: Antimicrobial activity of carvacrol, a constituent of oregano and thyme essential oil, has been demonstrated against C. jejuni in vitro, and this compound was found beneficial for broiler growth. Here, we tested a new liquid formulation that did not change the antibacterial efficacy of carvacrol against C. jejuni in vitro, as assessed by broth microdilution. The mode of action of carvacrol also remained unchanged as illustrated by electronic microscopy. A pharmacokinetic assay monitored carvacrol of the solid galenic formulation in the avian digestive tract and this showed that this compound was mainly found in the last part (caeca, large intestine) and in the droppings. Extremely low concentrations of free carvacrol were present in blood plasma, with larger amounts of carvacrol metabolites: carvacrol glucuronide and sulphate. A qPCR analysis showed that the solid galenic form of carvacrol added at 5 kg per tonne of food (i.e. 9·5 mg of carvacrol per kg of bodyweight per day) significantly decreased the C. jejuni caecal load by 1·5 log.CONCLUSIONS: The new liquid formulation was as effective as unformulated carvacrol in vitro. In vivo the solid galenic form seems to delay the carvacrol release into the caeca and presented interesting results on C. jejuni load after 35 days.SIGNIFICANCE AND IMPACT OF THE STUDY: Results suggested that this product could be promising to control Campylobacter contamination of broilers

Isolation, NMR Characterization, and Bioactivity of a Flavonoid Triglycoside from <i>Anthyllis henoniana</i> Stems: Antioxidant and Antiproliferative Effects on MDA-MB-231 Breast Cancer Cells

Plant extracts are considered as a large source of active biomolecules, especially in phytosanitary and pharmacological fields. Anthyllis henoniana is a woody Saharan plant located in the big desert of North Africa. Our previous research paper proved the richness of the methanol extract obtained from the stems in flavonoids and phenolic compounds as well as its remarkable antioxidant activity. In this research, we started by investigating the phytochemical composition of the methanol extract using high performance liquid chromatography coupled with electrospray ionization mass spectrometry (LC–MS/MS). Among the 41 compounds identified, we isolated and characterized (structurally and functionally) the most abundant product, a flavonoid triglycoside (AA770) not previously described in this species. This compound, which presents no cytotoxic activity, exhibits an interesting cellular antioxidant effect by reducing reactive oxygen species (ROS) generation, and an antiproliferative action on breast cancer cells. This study provides a preliminary investigation into the pharmacological potential of the natural compound AA770, isolated and identified from Anthyllis henoniana for the first time

Comparative investigation of the mechanisms of two cytotoxic venom peptides from the ant Tetramorium bicarinatum.

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