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International Journal of Molecular... May 2024Mycoses are one of the major causes of morbidity/mortality among immunocompromised individuals. Considering the importance of these infections, the World Health...
Mycoses are one of the major causes of morbidity/mortality among immunocompromised individuals. Considering the importance of these infections, the World Health Organization (WHO) defined a priority list of fungi for health in 2022 that include as belonging to the critical priority group and () to the medium priority group. The existence of few available antifungal drugs, their high toxicity, the acquired fungal resistance, and the appearance of new species with a broader spectrum of resistance, points out the need for searching for new antifungals, preferably with new and multiple mechanisms of action. The cyclam salt H[H(PhCH)Cyclam]Cl was previously tested against several fungi and revealed an interesting activity, with minimal inhibitory concentration (MIC) values of 8 µg/mL for and of 128 µg/mL for . The main objective of the present work was to deeply understand the mechanisms involved in its antifungal activity. The effects of the cyclam salt on yeast metabolic viability (resazurin reduction assay), yeast mitochondrial function (JC-1 probe), production of reactive oxygen species (DCFH-DA probe) and on intracellular ATP levels (luciferin/luciferase assay) were evaluated. H[H(PhCH)Cyclam]Cl induced a significant decrease in the metabolic activity of both and , an increase in Reactive Oxygen Species (ROS) production, and an impaired mitochondrial function. The latter was observed by the depolarization of the mitochondrial membrane and decrease in ATP intracellular levels, mechanisms that seems to be involved in the antifungal activity of H[H(PhCH)Cyclam]Cl. The interference of the cyclam salt with human cells revealed a CC value against HEK-293 embryonic kidney cells of 1.1 μg/mL and a HC value against human red blood cells of 0.8 μg/mL.
Topics: Antifungal Agents; Candida albicans; Humans; Reactive Oxygen Species; Candida; Microbial Sensitivity Tests; Mitochondria; Membrane Potential, Mitochondrial; Pichia
PubMed: 38791254
DOI: 10.3390/ijms25105209 -
Biotechnology Journal Jan 2024The biosynthesis of 2-phenylethanol (2-PE) at high yields and titers is often limited by its toxicity. In this study, we describe the molecular mechanisms of 2-PE...
The biosynthesis of 2-phenylethanol (2-PE) at high yields and titers is often limited by its toxicity. In this study, we describe the molecular mechanisms of 2-PE tolerance in the multi-stress tolerant industrial yeast, Candida glycerinogenes. They were different under 2-PE addition or fermentation conditions. After extracellular addition of 2-PE, C. glycerinogenes cells became rounder and bigger, which reduced specific surface area. However, during 2-PE fermentation C. glycerinogenes cells were smaller, which increased specific surface area. Other differences in the tolerance mechanisms were studied by analyzing the composition and molecular parameters of the cell membrane. Extracellular 2-PE stress resulted in down-regulation of transcriptional expression of unsaturated fatty acid synthesis genes. This raised the proportion of saturated fatty acids in the cell membrane, which increased rigidity of the cell membrane and reduced 2-PE entry to the cell. However, intracellular 2-PE stress resulted in up-regulation of transcriptional expression of unsaturated fatty acid synthesis genes, and increased the proportion of unsaturated fatty acids in the cell membrane; this in turn enhanced flexibility of the cell membrane which accelerated efflux of 2-PE. These contrasting mechanisms are mediated by transcriptional factors Hog1 and Swi5. Under 2-PE addition, C. glycerinogenes activated Hog1 and repressed Swi5 to upregulate erg5 and erg4 expression, which increased cell membrane rigidity and resisted 2-PE import. During 2-PE fermentation, C. glycerinogenes activated Hog1 and repressed Swi5 to upregulate 2-PE transporter proteins cdr1 and Acyl-CoA desaturase 1 ole1 to increase 2-PE export, thus reducing 2-PE intracellular toxicity. The results provide new insights into 2-PE tolerance mechanisms at the cell membrane level and suggest a novel strategy to improve 2-PE production by engineering anti-stress genes.
Topics: Phenylethyl Alcohol; Fermentation; Saccharomyces cerevisiae; Proteins; Cell Membrane; Fatty Acids, Unsaturated; Pichia
PubMed: 37840403
DOI: 10.1002/biot.202300181 -
European Journal of Clinical... May 2024This study investigates how surfactants affect the in-vitro anti-infective efficacy of micafungin, caspofungin, anidulafungin, and amphotericin B in treating pulmonary...
PURPOSE
This study investigates how surfactants affect the in-vitro anti-infective efficacy of micafungin, caspofungin, anidulafungin, and amphotericin B in treating pulmonary mycoses.
METHODS
MIC values for antifungal agents were determined against Candida krusei (now Pichia kudriavzevii) ATCC 6258, Candida albicans ATCC 90028, and 18 clinical isolates using the broth microdilution method in RPMI medium, following EUCAST recommendations. MIC assays included testing with and without Curosurf® surfactant at 1 mg/mL for C. krusei ATCC 6258 and all C. krusei isolates. Subsequent Time-kill studies in Sabouraud broth involved testing both C. albicans ATCC 90028 and C. krusei ATCC 6258 strains at concentrations equal their respective MIC values, with and without surfactant, using all four antifungals. CFU/mL were assessed at multiple time points up to 24 h. TKCs with different surfactant concentrations for C. krusei ATCC 6258 and mini-TKCs at various concentrations relative to the MIC of C. krusei isolates and the reference strain were conducted with micafungin, anidulafungin, and caspofungin.
RESULTS
MIC results showed that 1 µg/mL surfactant reduced killing of micafungin and anidulafungin against C. krusei, while caspofungin was unaffected. Amphotericin B's MIC decreased by half. TKCs demonstrated significant effects of surfactant on micafungin and anidulafungin against C. krusei, with complete abolition of anidulafungin's activity against C. albicans.
CONCLUSION
This in-vitro study highlights the concentration-dependent inhibitory effect of surfactant on antifungal activity against C. krusei and, to some extent, C. albicans, necessitating further clinical validation for invasive lung mycoses treatment.
Topics: Antifungal Agents; Microbial Sensitivity Tests; Humans; Pulmonary Surfactants; Candida albicans; Candida; Micafungin; Candidiasis; Amphotericin B; Echinocandins; Caspofungin
PubMed: 38483681
DOI: 10.1007/s10096-024-04799-7 -
Food Chemistry Jun 2024Valorization of fruit by-products is a crucial area of research for the development of innovative bio-based products. This study investigated the physicochemical...
Valorization of fruit by-products is a crucial area of research for the development of innovative bio-based products. This study investigated the physicochemical properties and health-promoting benefits of date syrup waste, both fermented by Pichia cecembensis or Pichia kudriavzevii (FDSW), and unfermented (CDSW). Metabolomics profiles of these samples were identified post in vitro digestion. FDSW exhibited 42 volatile compounds, including 9 new ones, and contained (-)-epicatechin, tyrosol, and gallic acid. Bioaccessible fractions of FDSW demonstrated substantial α-amylase inhibition, with percentages of 40.7 % and 53.9 %, respectively. FDSW displayed superior cytotoxicity against Caco2 and MCF-7 cancer cell lines, with an average of ∼75 % and 56 %, respectively. Untargeted metabolomics analysis revealed an increase in secondary metabolites, totaling 27 metabolites. LC-QTOF analysis of bioaccessible carbohydrate metabolites in FDSW identified two phytochemical groups, alkaloids, and terpenoids. This study underscores the potential of FDSW for producing value-added bio-based products with desirable characteristics and health benefits.
Topics: Humans; Caco-2 Cells; Fruit; Gallic Acid; Antioxidants; Metabolomics
PubMed: 38241989
DOI: 10.1016/j.foodchem.2024.138483 -
Journal of Agricultural and Food... Jan 2024Glycerol is an important platform compound with multidisciplinary applications, and glycerol production using low-cost sugar cane bagasse hydrolysate is promising. , an...
Glycerol is an important platform compound with multidisciplinary applications, and glycerol production using low-cost sugar cane bagasse hydrolysate is promising. , an industrial yeast strain known for its high glycerol production capability, has been found to thrive in bagasse hydrolysate obtained through a simple treatment without detoxification. The engineered exhibited significant resistance to furfural, acetic acid, and 3,4-dimethylbenzaldehyde within undetoxified hydrolysates. To further enhance glycerol production, genetic modifications were made to to enhance the utilization of xylose. Fermentation of undetoxified bagasse hydrolysate by CgS45 resulted in a glycerol titer of 40.3 g/L and a yield of 40.4%. This process required only 1 kg of bagasse to produce 93.5 g of glycerol. This is the first report of glycerol production using lignocellulose, which presents a new way for environmentally friendly industrial production of glycerol.
Topics: Glycerol; Candida; Lignin; Fermentation; Saccharomyces cerevisiae; Xylose; Pichia
PubMed: 38194497
DOI: 10.1021/acs.jafc.3c05818 -
Food Chemistry: X Jun 2024Kombucha is a traditional beverage produced by a living culture known as SCOBY or "symbiotic culture of bacteria and yeast". Culture-dependent production is essential...
Kombucha is a traditional beverage produced by a living culture known as SCOBY or "symbiotic culture of bacteria and yeast". Culture-dependent production is essential for stable kombucha fermentation. The aim of this study was to design a microbial community and to determine the effect of that community on the flavor and chemical properties of kombucha. The fermentations were carried out using combinations of selected species including and , which were previously isolated from kombucha. The effects of monocultures and cocultures on fermentation were investigated. The highest acetic acid producer was , which has strong antioxidant properties. In the monoculture and coculture fermentations, aldehydes, acids, and esters were generally observed at the end of fermentation. This study confirms that microbiota reconstruction is a viable approach for achieving the production of kombucha with increased bioactive constituents and consumer acceptance.
PubMed: 38808165
DOI: 10.1016/j.fochx.2024.101469 -
American Journal of Respiratory and... Mar 2024
Topics: Humans; Pichia; Cocaine; Mycoses; Thrombosis
PubMed: 38207072
DOI: 10.1164/rccm.202305-0828IM -
Microbiology Spectrum Jan 2024is a promising industrial chassis to produce biofuels and bioproducts due to its high tolerance to multiple environmental stresses such as low pH, heat, and other...
is a promising industrial chassis to produce biofuels and bioproducts due to its high tolerance to multiple environmental stresses such as low pH, heat, and other chemicals otherwise toxic for the most widely used microbes. Yet, little is known about specific mechanisms of such tolerance in this organism, hindering our ability to engineer this species to produce valuable biochemicals. Here, we report a comprehensive study of the mechanisms of acidic tolerance in this species via transcriptome profiling across variable pH for 12 different strains with different phenotypes. We found multiple regulatory mechanisms involved in tolerance to low pH in different strains of , marking potential targets for future gene editing and perturbation experiments.
Topics: Pichia; Transcriptome; Gene Expression Profiling; Hydrogen-Ion Concentration
PubMed: 38018981
DOI: 10.1128/spectrum.02536-23 -
Bioresource Technology May 2024This study presents a cost-effective strategy for producing organic acids from glucose and xylose using the acid-tolerant yeast, Issatchenkia orientalis. I. orientalis...
This study presents a cost-effective strategy for producing organic acids from glucose and xylose using the acid-tolerant yeast, Issatchenkia orientalis. I. orientalis was engineered to produce lactic acid from xylose, and the resulting strain, SD108XL, successfully converted sorghum hydrolysates into lactic acid. In order to enable low-pH fermentation, a self-buffering strategy, where the lactic acid generated by the SD108XL strain during fermentation served as a buffer, was developed. As a result, the SD108 strain produced 67 g/L of lactic acid from 73 g/L of glucose and 40 g/L of xylose, simulating a sugar composition of sorghum biomass hydrolysates. Moreover, techno-economic analysis underscored the efficiency of the self-buffering strategy in streamlining the downstream process, thereby reducing production costs. These results demonstrate the potential of I. orientalis as a platform strain for the cost-effective production of organic acids from cellulosic hydrolysates.
Topics: Lactic Acid; Xylose; Glucose; Cost-Benefit Analysis; Fermentation; Saccharomyces cerevisiae; Pichia
PubMed: 38552861
DOI: 10.1016/j.biortech.2024.130641