Examinando por Materia "Lipopeptides"
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Ítem Analysis of bioenergetic function alterations as part of the antifungal effect of cyclic lipopeptides and cinnamon extract against Fusarium spp. and Colletotrichum spp.(Universidad EAFIT, 2023) Ramírez Mejía, Julieta María; Gómez Ramírez, Luis Alejandro; Villegas Escobar, ValeskaÍtem Antifungal activity of lipopeptides isolated from Bacillus subtilis EA-CB0015 against Colletotrichum acutatum EAHP-008 is not related to an impairment in cellular bioenergetic reserve capacity(Universidad EAFIT, 2019) Tobón Ospina, Juliana; Gómez Ramirez, Luis Alejandro; Gómez Ramirez, Luis AlejandroÍtem Biocontrol activity of Bacillus subtilis EA-CB0015 cells and lipopeptides against postharvest fungal pathogens(Academic Press Inc., 2017-11-01) Arroyave-Toro J.J.; Mosquera S.; Villegas-Escobar V.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)Post-harvest diseases are responsible for significant losses worldwide, especially the plant pathogenic fungi Botrytis cinerea and Colletotrichum sp. are particularly severe and devastating. In this study, nine fungal pathogens were screened for growth inhibition by Bacillus subtilis EA-CB0015 strain and its metabolites. In vitro inhibitory assays showed that B. subtilis EA-CB0015 cells and the cell free supernatant (CFS) inhibited the growth of the tested fungal pathogens with different susceptibilities. Therefore, the antifungal activities of lipopeptides iturin A and fengycin C contained in the CFS, were tested against C. acutatum and B. cinerea. C. acutatum was more susceptible with minimal inhibitory concentrations (MIC) of 32 ppm (iturin A) and 128 ppm (fengycin C). Fruit and flower trials confirmed that B. subtilis EA-CB0015 cells and its lipopeptides reduced postharvest disease development but to differing degrees. Anthracnose symptoms caused by C. acutatum in tamarillo fruits were completely abolished by CFS, iturin A and fengycin C and reduced by 76% when treated with B. subtilis cells. In contrast, grey mold disease symptoms caused by B. cinerea in chrysanthemum flowers were inhibited by 72% when treated with lipopeptides and by 39% when applied with B. subtilis EA-CB0015 cells. Our results indicate that lipopeptides and cells of B. subtilis EA-CB0015 have a broad antifungal spectrum and control postharvest diseases caused by susceptible fungal pathogens. Our findings open the possibility of incorporating this biological control agent into different disease management programs.Ítem Fengycin C produced by Bacillus subtilis EA-CB0015.(AMER CHEMICAL SOC, 2013-04-26) Villegas-Escobar, Valeska; Ceballos, Isabel; Mira, John J.; Edith Argel, Luz; Orduz Peralta, Sergio; Romero-Tabarez, Magally; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)Bacillus subtilis EA-CB0015 was isolated from the phyllosphere of a banana plant and tested for its potential to produce bioactive compounds against Mycosphaerella fijiensis. Using a dual plate culture technique the cell-free supernatant of B. subtilis EA-CB0015 produced inhibition values of 89 +/- 1%. The active compounds were purified by solid-phase extraction and HPLC, and their primary structures determined using mass spectrometry and amino acid analysis. A new fengycin isoform, fengycin C, with the amino acid sequence Glu-Orn-Tyr-Thr-Glu-Val-Pro-Gln-Thr-Ile was isolated. The peptidic moiety differs from fengycin B at position 9 and from fengycin A at positions 6 and 9. The beta-hydroxy fatty acyl chain is connected to the N-terminal of the decapeptide and can be saturated or unsaturated, ranging from 14 to 18 carbons. The C-terminal residue of the peptidic moiety is linked to the tyrosine residue at position 3, forming the branching point of the acyl peptide and the eight-membered cyclic lactone.Ítem In vivo study : effect of essential oils and lipopeptides from Bacillus tequilensis EACB0015 on the growth of the phytopathogenic fungus Colletotrichum Acutatum EAHP-012(Universidad EAFIT, 2021) Orozco Vergel, Joana Paola; Gómez Ramírez, Luis AlejandroÍtem Inducible Antibacterial Activity in the Bacillales by Triphenyl Tetrazolium Chloride(Nature Publishing Group, 2020-01-01) Sierra-Zapata L.; Álvarez J.C.; Romero-Tabarez M.; Silby M.W.; Traxler M.F.; Behie S.W.; Pessotti R.C.; Villegas-Escobar V.; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y ConservaciónThe world is in the midst of an antimicrobial resistance crisis, driving a need to discover novel antibiotic substances. Using chemical cues as inducers to unveil a microorganism’s full metabolic potential is considered a successful strategy. To this end, we investigated an inducible antagonistic behavior in multiple isolates of the order Bacillales, where large inhibition zones were produced against Ralstonia solanacearum only when grown in the presence of the indicator triphenyl tetrazolium chloride (TTC). This bioactivity was produced in a TTC-dose dependent manner. Escherichia coli and Staphylococcus sp. isolates were also inhibited by Bacillus sp. strains in TTC presence, to a lesser extent. Knockout mutants and transcriptomic analysis of B. subtilis NCIB 3610 cells revealed that genes from the L-histidine biosynthetic pathway, the purine, pyrimidine de novo synthesis and salvage and interconversion routes, were significantly upregulated. Chemical space studied through metabolomic analysis, showed increased presence of nitrogenous compounds in extracts from induced bacteria. The metabolites orotic acid and L-phenylalaninamide were tested against R. solanacearum, E. coli, Staphylococcus sp. and B. subtilis, and exhibited activity against pathogens only in the presence of TTC, suggesting a biotransformation of nitrogenous compounds in Bacillus sp. cells as the plausible cause of the inducible antagonistic behavior. © 2020, The Author(s).