Examinando por Materia "Lipopeptides"

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    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, Valeska; Minciencias
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    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.
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    Combining cyclic lipopeptides and cinnamon extract enhance antifungal activity against Fusarium oxysporum strains pathogenic to banana and delay Fusarium wilt under greenhouse conditions
    (Springer, 2024-08-26) Ramírez-Mejía, Julieta M.; Aguilera-Galvez, Carolina; Kema, Gert H. J.; Valencia-Riascos, Luisa M; Zapata-Henao, Sebastián; Gómez, Luis A.; Villegas-Escobar, Valeska; Asociación de Bananeros de Colombia, AUGURA; Universidad EAFIT; Wageningen University and Research
    Fusarium wilt of banana (FWB) caused by the soil-borne fungus Fusarium oxysporum f. sp. cubense (Foc) is a widely distributed disease that generates devastating losses in banana production. Foc belongs to the Fusarium oxysporum species complex (FOSC) which includes several evolutionary lineages. Nine of them are pathogenic to banana such as F. phialophorum, F. grosmichelli, F. duoseptatum and the most aggressive F. odoratissimum tropical race 4 (TR4). No control method has been successfully implemented to manage FWB, then enhancing the potential of management approaches can avoid or delay disease epidemics and reduce disease severity. Here we determined the antifungal effect of different plant-based extracts against Foc in vitro, and whether the combination of cinnamon (Cinnamomum zeylanicum) extract and Bacillus tequilensis EA-CB0015 cyclic lipopeptides had an additive effect against different Foc lineages in vitro and against FWB in banana plants in greenhouse. We found, from 17 plant-based natural extracts, that cinnamon was highly active against Foc strain IB (race 1). Furthermore, cinnamon and cyclic lipopeptides inhibited different strains of various evolutionary lineages of Foc belonging to race 1 and TR4, and their combination increased in 1.4-fold the effect of the single extracts in vitro. Our results showed that soil concentration of F. odoratissimum TR4-II5 decreased by 1000-fold when treated with the combination of 488 mg L−1 cinnamon and 128 mg L−1 lipopeptides in a soil microcosm system after 5 days of incubation, followed by a partial population recovery after 21 days. In greenhouse experiments, the combination reduced external but not internal FWB symptoms, and cinnamon extract had a significant impact on internal plant symptoms. Taken together, the effect of cyclic lipopeptides with cinnamon extract on Foc supports their function towards delaying the effect of disease progression and suggests that the combination enhances the effect of the single extracts.
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    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.
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    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 Conservación
    The 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).
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    Lipopeptides from Bacillus tequilensis EA-CB0015 and cinnamon extract decrease the bioenergetic response of Fusarium oxysporum f. sp. Cubense
    (Springer, 2024-09) Ramírez-Mejía, Julieta M.; Villegas-Escobar, Valeska; Gómez, Luis A.; Asociación de Bananeros de Colombia, AUGURA; Universidad EAFIT
    Lipopeptides (LPs) from B. tequilensis EA-CB0015 have antifungal activity against Fusarium species. Specifically, against F. oxysporum f. sp. cubense (Foc), the cause of Fusarium wilt of banana. Cinnamon (CN) extract is also known for its inhibitory activity against the Fusarium genus. The main goal of this research was to determine whether the effect of LPs and CN extract or their combination against a Foc isolate is related to an impairment of mitochondrial function. Our results show that biomass decreased by 74% (p < 0.0001) and 84% (p < 0.0001) when cultures were treated with 128 ppm LPs and 152.5 ppm CN extract, respectively. In parallel, we found a pronounced impairment of the bioenergetic response. That is, the routine oxygen consumption rate diminished by 55% (p = 0.0148) and 38% (p < 0.0001), respectively. Moreover, the ATP-linked respiratory rate decreased by 63% (p = 0.0461) and 44% (p = 0.0005), while the FCCP-simulated respiratory rate by 63% (p = 0.0255) and 45% (p = 0.0002). Therefore, our data suggest that the altered bioenergetic response observed in cultures of Foc treated with LPs or CN is mainly caused by an impairment of the activity of the respiratory complexes. On the other hand, biomass production was reduced by 80% (p < 0.0001) when cultures were treated with a mixture comprising only 10% LPs and 40% CN extract. Furthermore, ATP-linked and FCCP-stimulated respiratory rates decreased by 62% (p = 0.0024) and 68% (p < 0.0001), respectively under the same conditions. A potentially synergistic antifungal effect of cyclic LPs with a CN extract is suggested.