RESUMEN
Background: This study explored the utilization of luffa sponge (LS) in enhancing acetification processes. LS is known for having high porosity and specific surface area, and can provide a novel means of supporting the growth of acetic acid bacteria (AAB) to improve biomass yield and acetification rate, and thereby promote more efficient and sustainable vinegar production. Moreover, the promising potential of LS and luffa sponge coated with κ-carrageenan (LSK) means they may represent effective alternatives for the co-production of industrially valuable bioproducts, for example bacterial cellulose (BC) and acetic acid. Methods: LS and LSK were employed as adsorbents for Acetobacter pasteurianus UMCC 2951 in a submerged semi-continuous acetification process. Experiments were conducted under reciprocal shaking at 1 Hz and a temperature of 32 °C. The performance of the two systems (LS-AAB and LSK-AAB respectively) was evaluated based on cell dry weight (CDW), acetification rate, and BC biofilm formation. Results: The use of LS significantly increased the biomass yield during acetification, achieving a CDW of 3.34 mg/L versus the 0.91 mg/L obtained with planktonic cells. Coating LS with κ-carrageenan further enhanced yield, with a CDW of 4.45 mg/L. Acetification rates were also higher in the LSK-AAB system, reaching 3.33 ± 0.05 g/L d as opposed to 2.45 ± 0.05 g/L d for LS-AAB and 1.13 ± 0.05 g/L d for planktonic cells. Additionally, BC biofilm formation during the second operational cycle was more pronounced in the LSK-AAB system (37.0 ± 3.0 mg/L, as opposed to 25.0 ± 2.0 mg/L in LS-AAB). Conclusions: This study demonstrates that LS significantly improves the efficiency of the acetification process, particularly when enhanced with κ-carrageenan. The increased biomass yield, accelerated acetification, and enhanced BC biofilm formation highlight the potential of the LS-AAB system, and especially the LSK-AAB variant, in sustainable and effective vinegar production. These systems offer a promising approach for small-scale, semi-continuous acetification processes that aligns with eco-friendly practices and caters to specialized market needs. Finally, this innovative method facilitates the dual production of acetic acid and bacterial cellulose, with potential applications in biotechnological fields.
Asunto(s)
Ácido Acético , Acetobacter , Biomasa , Carragenina , Carragenina/química , Acetobacter/metabolismo , Ácido Acético/química , Ácido Acético/metabolismo , Luffa/química , Adsorción , Celulosa/metabolismo , Celulosa/química , Biopelículas/crecimiento & desarrolloRESUMEN
Repetitive uses of antifungals result in a worldwide crisis of drug resistance; therefore, natural fungicides with minimal side-effects are currently sought after. This study aimed to investigate antifungal property of 19, 20-epoxycytochalasin Q (ECQ), derived from medicinal mushroom Xylaria sp. BCC 1067 of tropical forests. In a model yeast Saccharomyces cerevisiae, ECQ is more toxic in the erg6∆ strain, which has previously been shown to allow higher uptake of many hydrophilic toxins. We selected one pathway to study the effects of ECQ at very high levels on transcription: the ergosterol biosynthesis pathway, which is unlikely to be the primary target of ECQ. Ergosterol serves many functions that cholesterol does in human cells. ECQ's transcriptional effects were correlated with altered sterol and triacylglycerol levels. In the ECQ-treated Δerg6 strain, which presumably takes up far more ECQ than the wild-type strain, there was cell rupture. Increased actin aggregation and lipid droplets assembly were also found in the erg6∆ mutant. Thereby, ECQ is suggested to sensitize yeast cells lacking ERG6 through actin-targeting and consequently but not primarily led to disruption of lipid homeostasis. Investigation of cytochalasins may provide valuable insight with potential biopharmaceutical applications in treatments of fungal infection, cancer or metabolic disorder.
Asunto(s)
Actinas/antagonistas & inhibidores , Antifúngicos/farmacología , Citocalasinas/farmacología , Metabolismo de los Lípidos/efectos de los fármacos , Saccharomyces cerevisiae/efectos de los fármacos , Xylariales/metabolismo , Metiltransferasas/genética , Saccharomyces cerevisiae/genéticaRESUMEN
Multidrug resistance is a highly conserved phenomenon among all living organisms and a major veritable public health problem worldwide. Repetitive uses of antibiotics lead to antimicrobial drug resistance. Here, 19,20-epoxycytochalasin Q (ECQ) was isolated from endophytic fungus Xylaria sp. BCC 1067 and, its chemical structure was determined via chromatographic and spectral methods. ECQ displayed an antifungal activity with low MIC50 of 410 and 55 mg/l in the model yeast Saccharomyces cerevisiae wild-type and ScΔpdr5 strains, respectively. ECQ was a new inducer and potential substrate of key multi-drug efflux pumps S. cerevisiae ScPdr5 and Candida albicans CaCdr1. ECQ targeted actin filament, disrupting actin dynamics of yeast cells. ECQ also sensitized the ScΔsrv2 mutant, lacking suppressor of RasVal19. Overexpression of ScPDR5 or CaCDR1 genes prevented aggregation of actin and alleviated antifungal effect of ECQ. Additionally, ECQ induced high accumulation of reactive oxygen species, caused plasma membrane leakage and decreased yeast cell survival. Importantly, a discovery of ECQ implied a cellular connection between multi-drug resistance and actin stability, an important determinant of transporter mediated-drug resistance mechanism. Combination of ECQ and antifungal azoles displayed promising drug synergy against S. cerevisiae strains expressing multi-drug transporters, thereby providing potential solution for antifungal therapy and chemotherapeutic application.
Asunto(s)
Actinas/metabolismo , Antifúngicos/farmacología , Azoles/farmacología , Candida albicans/efectos de los fármacos , Citocalasinas/farmacología , Especies Reactivas de Oxígeno/metabolismo , Saccharomyces cerevisiae/efectos de los fármacos , Xylariales/química , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Actinas/química , Antifúngicos/química , Antifúngicos/metabolismo , Candida albicans/genética , Candida albicans/metabolismo , Citocalasinas/metabolismo , Farmacorresistencia Fúngica , Sinergismo Farmacológico , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Xylariales/metabolismoRESUMEN
Benefits of whole grains as dietary supplements and active ingredients in health products have been promoted. Despite being neglected as an agricultural byproduct of polished rice, pigmented rice bran has emerged as a promising source of natural anti-aging compounds. Indeed, the extract of red rice bran Hom Dang cultivar contained rich phenolic acids and flavonoids. It displayed high antioxidant activities in vitro and in vivo assays. Using yeast model, extract and bioactive compounds, quercetin and protocatechuic acid found in the rice bran pericarp, effectively reduced levels of intracellular reactive oxygen species (ROS), restored plasma membrane damages and prolonged life-span of pre-treated wild-yeast cells. Importantly, these molecules modulated life span-extension through a mechanism of ROS reduction that resembles to that operated under the highly conserved Tor1- and Sir2-dependent signaling pathways, with the human homologs TORC1 and SIRT1, respectively. The key longevity factors Sch9 and Rim15 kinases, Msn2/4 regulators and a novel transcription factor Asg1, the antioxidant enzymes superoxide dismutases and glutathione peroxidases played important role in mediating longevity. Yeast clearly provides an instrumental platform for rapid screening of compounds with anti-aging efficacies and advances knowledge in the molecular study of ageing.
Asunto(s)
Antioxidantes/farmacología , Senescencia Celular/efectos de los fármacos , Oryza/química , Extractos Vegetales/farmacología , Saccharomyces cerevisiae/efectos de los fármacos , Membrana Celular/efectos de los fármacos , Evaluación Preclínica de Medicamentos/métodos , Especies Reactivas de Oxígeno/metabolismo , Saccharomyces cerevisiae/citología , Saccharomyces cerevisiae/fisiología , Transducción de Señal/efectos de los fármacos , Factores de TiempoRESUMEN
AIM: To investigate antifungal potential of Xylaria sp. BIOTEC culture collection (BCC) 1067 extract against the model yeast Saccharomyces cerevisiae. MATERIALS & METHODS: Antifungal property of extract, reactive oxygen species levels and cell survival were determined, using selected deletion strains. RESULTS: Extract showed promising antifungal effect with minimal inhibitory concentration100 and minimal fungicidal concentration of 500 and 1000 mg/l, respectively. Strong synergy was observed with fractional inhibitory concentration index value of 0.185 for the combination of 60.0 and 0.5 mg/l of extract and ketoconazole, respectively. Extract-induced intracellular reactive oxygen species levels in some oxidant-prone strains and mediated plasma membrane rupture. Antioxidant regulator Yap1, efflux transporter Pdr5 and ascorbate were pivotal to protect S. cerevisiae from extract cytotoxicity. CONCLUSION: Xylaria sp. BCC 1067 extract is a potentially valuable source of novel antifungals.
Asunto(s)
Antifúngicos/farmacología , Productos Biológicos/farmacología , Mezclas Complejas/farmacología , Farmacorresistencia Fúngica Múltiple , Estrés Oxidativo , Saccharomyces cerevisiae/efectos de los fármacos , Xylariales/química , Antifúngicos/aislamiento & purificación , Productos Biológicos/aislamiento & purificación , Mezclas Complejas/aislamiento & purificación , Viabilidad Microbiana/efectos de los fármacos , Especies Reactivas de Oxígeno/análisisRESUMEN
In this study, we characterize a new function for activator of stress response genes (Asg1) in fatty acid utilization. Asg1 is required for full activation of genes in several pathways, including ß-oxidation (POX1, FOX2, and POT1), gluconeogenesis (PCK1), glyoxylate cycle (ICL1), triacylglycerol breakdown (TGL3), and peroxisomal transport (PXA1). In addition, the transcriptional activator Asg1 is found to be enriched on promoters of genes in ß-oxidation and gluconeogenesis pathways, suggesting that Asg1 is directly involved in the control of fatty acid utilizing genes. In agreement, impaired growth on non-fermentable carbons such as fatty acids and oils and increased sensitivity to some oxidative agents are found for the Δasg1 strain. The lipid class profile of the Δasg1 cells grown in oleate displays approximately 3-fold increase in free fatty acid (FFA) content in comparison to glucose-grown cells, which correlates with decreased expression of ß-oxidation genes. The ∆asg1 strain grown in glucose also exhibits higher accumulation of triacylglycerols (TAGs) during log phase, reaching levels typically observed in stationary phase cells. Altered TAG accumulation is partly due to the inability of the Δasg1 cells to efficiently break down TAGs, which is consistent with lowered expression of TGL3 gene, encoding triglycerol lipase. Overall, these results highlight a new role of the transcriptional regulator Asg1 in coordinating expression of genes involved in fatty acid utilization and its role in regulating cellular lipid accumulation, thereby providing an attractive approach to increase FFAs and TAGs content for the production of lipid-derived biofuels and chemicals in Saccharomyces cerevisiae.