Search Results (124)

A simple and rapid precipitation process was successfully employed to prepare silver phosphate (SP, Ag₃PO₄). Two different phosphate sources: diammonium hydrogen phosphate ((NH₄)₂HPO₄) and dipotassium hydrogen phosphate (K₂HPO₄) were applied separately as the precursor, obtaining ((NH₄)₂HPO₄)⁻ and K₂HPO₄⁻ derived SP powders, named SP-A or SP-P, respectively. Fourier transform infrared (FTIR) spectra pointed out the vibrational characteristics of P–O and O–P–O interactions, confirming the presence of the PO43– functional group for SP. X-ray diffraction (XRD) patterns revealed that the SP crystallized in a cubic crystal structure. Whereas the field emission scanning electron microscope (FESEM) exposed spherical SP particles. The potentially antibacterial activity of SP-A and SP-P against bacterial Bacillus stratosphericus, yeast Meyerozyma guilliermondii, and fungal Phanerodontia chrysosporium was subsequently investigated. All studied microorganisms were recovered and isolated from the aquatic plant during the tissue culture process. The preliminary result of the antimicrobial test revealed that SP-A has higher antimicrobial activity than SP-P. The superior antimicrobial efficiency of SP-A compared to SP-P may be attributed to its purity and crystallite size, which provide a higher surface area and more active sites. In addition, the presence of potassium-related impurities in SP-P could have negatively affected its antimicrobial performance. These findings suggest that SP holds potential as an antimicrobial agent for maintaining sterility in tissue cultures, particularly in aquatic plant systems. The growth of both B. stratosphericus and M. guilliermondii was suppressed effectively at 30 ppm SP-A, whereas 10 ppm of SP-A can suppress P. chrysosporium development. This present work also highlights the potential of SP at very low concentrations (10–30 ppm) for utilization as an effective antimicrobial agent in tissue culture, compared to a commercial antimicrobial agent, viz., acetic acid, at the same concentration. Full article

The increasing resistance of pathogenic microorganisms to antimicrobials has driven the search for safe and sustainable alternatives. In this context, microbial biosurfactants have gained prominence due to their antimicrobial activity, low toxicity, and high stability under extreme conditions. This study presents the production and characterization of a biosurfactant with antimicrobial potential, obtained from Bacillus subtilis isolated from soil, for application in the control of resistant strains. Bacterial identification was performed using mass spectrometry (MALDI-TOF), confirming it as Bacillus subtilis. The strain B. subtilis UCP 1533 was cultivated using different carbon sources (glucose, soybean oil, residual frying oil, and molasses) and nitrogen sources (ammonium chloride, sodium nitrate, urea, and peptone), with evaluations at 72, 96, and 120 h. The best condition involved a mineral medium supplemented with 2% soybean oil and 0.12% corn steep liquor, resulting in the production of 16 g·L⁻¹ of biosurfactant, with a critical micelle concentration (CMC) of 0.3 g·L⁻¹ and a reduction in water surface tension to 25 mN·m⁻¹. The biosurfactant showed an emulsification index of 100% for used motor oil and ranged from 50% to 100% for different vegetable oils, maintaining stability across a wide range of pH, salinity, and temperature. FT-IR and NMR analyses confirmed its lipopeptide nature and anionic charge. Toxicity tests with Tenebrio molitor larvae showed 100% survival at all the tested concentrations. In phytotoxicity assays, seed germination rates above 90% were recorded for Solanum lycopersicum and Lactuca sativa. Antimicrobial tests revealed inhibitory activity against resistant strains of Escherichia coli and Pseudomonas aeruginosa, as well as against species of the genus Candida (C. glabrata, C. lipolytica, C. bombicola, and C. guilliermondii), highlighting the biosurfactant as a promising alternative in combating antimicrobial resistance (AMR). These results indicate the potential application of this biosurfactant in the development of antimicrobial agents for pharmaceutical formulations and sustainable strategies for phytopathogen control in agriculture. Full article

Background/Objectives: Candidiasis, an opportunistic fungal infection caused by Candida species, is a major health problem, particularly in immunocompromised individuals. Increasing resistance of yeasts such as Candida spp. to pharmacological antifungal agents makes it necessary to explore alternative treatments. The aim of this study was to evaluate the antifungal potential of Gomortega keule essential oil (GKEO) against Candida spp. by assessing growth and development at 24 and 48 h. Encapsulation and characterization of a stable nanoemulsion were carried out to enhance efficacy. Methods: The anti-yeast activity of both free GKEO and the nanoemulsion against Candida albicans, C. glabrata, and C. guilliermondii was evaluated using a microdilution method to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) at 24 and 48 h. Results: GC-MS/MS analysis identified forty-one components in GKEO, the main ones being eucalyptol (21.41%), 4-terpineol (19.62%), and α-terpinyl acetate (13.89%). Antifungal assays revealed that both free and nanoemulsion-formulated GKEO inhibited the growth of all tested Candida strains. At 48 h, the nanoformulated GKEO achieved a MIC value of 32 µg/mL and an MFC of 64 µg/mL for C. albicans and C. glabrata and showed higher antifungal activity compared to the free oil, in particular against C. albicans, exhibiting a four-fold lower MFC value. The activity of the nanoformulation was comparable to or better than fluconazole against C. glabrata and C. guilliermondii. Conclusions: The GKEO nanoemulsion potentiated anti-yeast activity against Candida spp. The formulation improved the efficacy of GKEO, suggesting its potential as an alternative or adjunctive treatment for candidiasis. Full article

This study evaluates the feasibility of using banana peels as a substrate for cultivating fodder yeast biomass. Banana peels (BPs), representing approximately 38% of the total fruit weight, are rich in cellulose and hemicellulose, thus presenting a significant opportunity for valorisation. The study investigates the effects of microwave and ultrasound treatments on the hydrolysis efficiency of banana peels and the subsequent cultivation of yeast. Two yeast strains, Scheffersomyces stipitis and Meyerozyma guilliermondii, were cultivated in hydrolysates prepared using various methods, including acid–thermal, enzymatic, microwave, and ultrasound treatments. The results demonstrate that enzymatic hydrolysis following microwave or ultrasound pretreatment significantly enhances sugar release, supporting higher biomass yields. The maximum biomass concentration achieved was 7.68 g DM/L, with crude protein content reaching up to 45.46% DM. These results indicate that banana peels can be effectively utilised for single-cell protein production, providing a sustainable alternative for animal feed. The study underscores the potential of integrating microwave and ultrasound technologies in bioprocessing to enhance the efficiency and environmental sustainability of yeast cultivation. Full article

With rising multidrug-resistant yeast pathogens, conventional antifungals are becoming less effective, urging the need for adjuvants that enhance their activity at lower doses. This study evaluated the synergistic activity of antimicrobial peptidomimetics (TM8 and RK758) or colistin sulphate in combination with conventional antifungals against Candida albicans, C. tropicalis, C. parapsilosis, Meyerozyma guilliermondii, Nakaseomyces glabratus, Pichia kudriavzevii and Kluyveromyces marxianus, and Candidozyma auris using the checkerboard microdilution test. RK758 was synergistic with fluconazole in 78% of isolates, with the remaining 22% of isolates still showing partial synergy; it showed synergy with amphotericin B in 56% of isolates, and with caspofungin, 78% of isolates exhibited either synergy or partial synergy. TM8 showed synergy with fluconazole in 44% (with partial synergy in another 44%) of isolates, with amphotericin B in 67% of isolates, and with caspofungin in 44% (with partial synergy in another 44%) of isolates. Colistin with fluconazole or caspofungin exhibited synergy or partial synergy in 56% of the isolates. No antagonism was observed in any of the combinations. Additionally, a time-kill assay further demonstrated synergistic activity between fluconazole and TM8 or RK758. The effects of these peptidomimetics on cell membrane integrity were demonstrated in an ergosterol binding assay, supported by SYTOX Green and cellular leakage assays, both indicating a lytic effect. These results suggest that peptidomimetics can synergise with conventional antifungals, offering a potential strategy for combination therapy against yeast infections. The membrane lytic activity of the peptidomimetics likely plays a role in their synergistic interaction with antifungals, thereby enhancing the antimicrobial activities of both compounds at sub-MIC levels. Full article

Coinfection rates of candidiasis in patients affected by COVID-19 had a significantly increase during the sanitary contingency. The objective of this scoping review is to analyze the available scientific evidence around the coinfection of invasive candidiasis in hospitalized patients with severe COVID-19 disease. Online databases such as PubMed, EBSCO, SciFinder, Scopus, and SciELO were used to analyze the different scientific studies published from January 2020 to December 2022, selecting 48 publications that reported comorbidity between invasive candidiasis and COVID-19 as a study variable. Based on the PRISMA-ScR extension for scoping reviews, we identified more than half of the publications (57%) as observational, descriptive, and analytic studies, while 43% were systematic reviews. Overall, up to 169,468 adult patients admitted to the intensive care unit were examined. Coinfection was due mainly to Candida albicans (75%), but some more species were reported such as Meyerozyma parapsilosis (formerly Candida parapsilosis); Meyerozyma guilliermondii (formerly Candida guilliermondii); Nakaseomyces glabratus (formerly Candida glabrata); Candida tropicalis; Candida dubliniensis; Clavispora lusitaniae (formerly Candida lusitaniae); and Pichia kudriavzevii (formerly Candida krusei). We concluded that patients infected by SARS-CoV-2 had a higher incidence of fungal coinfections, thus increasing the mortality rate, disease severity, and length of hospital stay in the intensive care unit. Full article

This review compares 32 studies (2000–2024) on plant- and microbial-based organic disease management to control grapevine pests and diseases. A systematic literature search provided 24 studies on microbial agents and 8 on plant treatments. Their effectiveness against key pathogens, including downy mildew, powdery mildew, and gray mold, was compared. Microbial agents such as Candida sake inhibited Botrytis cinerea by up to 80% in the lab and Pseudomonas sp. dramatically reduced grapevine lesion lengths by 32–52% in field conditions, while Bacillus subtilis reduced powdery mildew by 96% in greenhouse conditions and A. pullulans reduced Ochratoxin A infection by 99% in field conditions. In laboratory conditions, C. guilliermondii A42 reduced grape rot to 8–22% and A. cephalosporium B11 reduced it to 16–82%, confirming A42’s greater efficacy. Plant-derived agents and essential oils, including lavender and cinnamon, suppressed 100% of pathogens in vitro, whereas copper coupled with plant-derived agents reduced disease incidence by up to 92% under field conditions. While promising, plant-derived agents are plagued by formulation instability, which affects shelf life and effectiveness, while microbial agents must be kept under stringent storage conditions and can be variable under different vineyard conditions. These limitations identify the requirement for a stronger formulation strategy and large field validations. Organic disease management offers several important benefits, such as environmental safety, biodegradability, compatibility with organic cultivation, and low pesticide dependence. The application of these agents in pest management systems is ecologically balanced, improves soil health, and enables sustainable vineyard management. Full article

European hedgehogs are an important reservoir for many pathogens of health interest. Since hedgehogs live in close contact with humans, potential zoonotic fungi raise significant public health concerns, especially in areas with a high hedgehog density. From 2020 to 2023, 134 hedgehogs were surveyed for potential zoonotic fungi. Non-invasive methods were used, such as brushing live animals with a sterile toothbrush and taking oral and rectal swabs from deceased ones (86 animals). Dermatophytes were cultured on Dermasel agar and identified using molecular tools, while yeasts were isolated on Sabouraud agar with chloramphenicol and determined using Candida Chromogenic agar (MicroBiolDiagnostici^®, Cagliari, Italy) and MALDI-TOF (Microflex LT Smart Biotyper with FlexControlBiotyper 3.4 software, Bruker Daltonics, Bremen, Germany). Minimum inhibitory concentrations (MICs) were determined for Candida albicans isolates. Dermatophytes were found in just one hedgehog (0.8%, 95% C.I.: 0–0.04), identified as Paraphyton mirabile. Yeasts were detected in 22 of 86 hedgehogs (25.6%, 95% C.I.: 16.4–34.8), with 25 isolates obtained, including 21 Candida albicans, 2 Yarrowia lipolytica, 1 Rhodotorula mucilaginosa, and 1 Meyerozyma guilliermondii. All C. albicans isolates showed a high susceptibility to the antimycotic panel tested. Monitoring zoonotic fungi harbored by European hedgehogs, as well as raising public awareness on the topic, is of great importance for public health. Full article

The aim of this study was to evaluate bioactive properties of Basidiomycota fungi, mainly Suillus sp. Wide spectrum of activities were revealed for S. variegatus, S. luteus, S. bovinus and S. granulatus; and obtained results were compared with other common fungi. Total Phenolic Content (TPC) varied from 245.32 ± 5.45 to 580.77 ± 13.10 (mg (GAE) per 100 g of dry weight) in methanolic extracts of S. bovinus and S. granulatus fruiting bodies, respectively. In ethyl acetate extracts, the highest TPC were obtained for S. variegatus (310 ± 9.68, mg (GAE)/100 g, dry matter), and the lowest means for S. luteus (105 ± 3.55, mg (GAE)/100 g dry weight). The ethyl acetate extracts of the tested Suillus species exhibited a stronger antioxidant activity (AA) to scavenge DPPH^● and ABTS^•+ than the methanolic ones, and the highest effects were determined for S. luteus (EC₅₀, 0.15 ± 0.05 and 0.23 ± 0.05%, respectively). In the case of methanolic extracts, the highest AA were evaluated for S. granulatus. (EC₅₀ for DPPH^● and ABTS^•+, 0.81 ± 0.30 and 0.95 ± 0.22%, respectively). The ABTS^•+ scavenging potential varied from 0.25 ± 0.05 to 0.74 ± 0.10 (mmol/L, TROLOX equivalent, for S. granulatus and S. variegatus fruiting body extracts, respectively) in the ethyl acetate extracts. S. granulatus extracts demonstrated the widest range of antimicrobial effects against both gram-positive and gram-negative bacteria (from 11.7 ± 1.3 to 28.5 ± 3.3 mm against Pseudomonas aeruginosa and Bacillus mycoides, respectively); and against two fungal strains (up to 13.6 ± 0.4 mm on Meyerozyma guilliermondii) in agar disc diffusion tests. Our study revealed that methanolic extracts of the most tested Suillus sp. were not active enough against the tested parasites: Trypanosoma cruzi, Trypanosoma brucei, Leishmania infantum and Plasmodium falciparum. Only S. variegatus extracts showed good antiprotozoal effects against P. falciparum (12.70 µg/mL). Cytotoxic activity was observed on human diploid lung cells MRC-5 SV2 by S. granulatus extracts (64.45 µg/mL). For comparative purposes, extracts of other common Lithuanian fungi, such as Xerocomus sp. (X. badius, X. chrysenteron and X. subtomentosus), Tylopilus felleus, Phallus impudicus and Pycnoporus cinnabarinus were investigated for their activity. The P. cinnabarinus extracts demonstrated the highest and broadest overall effects: 1.32 µg/mL against T. brucei, 1.46 µg/mL against P. falciparum, 3.93 µg/mL against T. cruzi and 21.53 µg/mL against L. infantum. Additionally, this extract exhibited strong cytotoxicity on MRC-5 cells (13.05 µg/mL). The investigation of bioactive fungal metabolites is important for the development of a new generation of antioxidants, antimicrobials, antiparasitic and anticancer agents. Full article

The marine oleaginous microalga Microchloropsis gaditana (formerly Nannochloropsis gaditana) exhibits a high capacity to thrive in a broad range of environmental conditions, being predominantly utilized as feed in aquaculture. This article reports the characterization of the culturable yeast population present during the scale-up process of M. gaditana cultivation at Necton S.A. facilities, from 5 L flasks until tubular photobioreactors. The 146 yeast isolates obtained, molecularly identified based on D1/D2 and ITS nucleotide sequences, belong to the species Rhodotorula diobovata, R. mucilaginosa, R. taiwanensis, R. sphaerocarpa, Vishniacozyma carnescens, Moesziomyces aphidis, and Meyerozyma guilliermondii. The yeast abundance was found to increase throughout upscaling stages. The yeast populations isolated from microalgal cultures and water samples share phylogenetically close isolates, indicating a possible common source. The impressive high percentage of red yeasts isolated (90%) is consistent with the recognized role of carotenoid pigments in yeast photoprotection. Sixty yeast isolates were tested for lipid (Nile Red staining) and biosurfactant (oil drop dispersion and emulsification index) production. Results revealed that these capacities are common features. Microbial lipids and biosurfactants have promising biotechnological applications. Moreover, biosurfactants can fulfill various physiological roles and provide advantages in natural environments contributing to the promising use of yeasts as probiotics in microalgae production. Full article

Background: The increased rates of common fungal diseases are a constant challenge. Therefore, the search for plant-based compounds with antifungal activity, particularly ones against Candida species, is always relevant in the medical context. However, most of the studies have focused on screening the antifungal activity of extracts rather than isolated compounds. Based on this, we aimed to analyze and organize a comprehensive overview of the antifungal and other biological activities of isolated compounds found in Anacardiaceae family vegetal species, covering mechanisms of action and potential therapeutic applications. Results: The extracts, essential oils, and compounds are frequently assayed for anti-Candida activity using the in vitro minimum inhibitory concentration (MIC), minimum fungicide concentration (MFC), and halo inhibition assays. Candida albicans, C. tropicalis, C. parapsilosis, C. glabrata, C. krusei, and C. guilliermondii were the most tested fungus species. Essential oils were the most used form (37% of the studies). The isolated compounds included shikimic acid, 2-hydroxy-1,8-cineole β-D-glucopyranoside, myricitrin, cardanol, estragole, trans-anethole, β-caryophyllene, myrcene, catechin-3-O-rhamnoside, β-sitosterol-3-O-glucoside, 24Z-isomasticadienolic acid, oleanolic acid, pistagremic acid, apigenin, sakuranetin, oleanolic aldehyde, and integriside. Conclusions: Our data indicate that the compounds isolated from Anacardiaceae species show promise for developing new therapeutic antifungal drugs, mainly if we consider their other biological activities, including anti-inflammatory, antioxidant, and apoptotic effects. In this context, they may be candidates for future treatments of fungal infections, especially in combination with conventional antifungals or when used in nanostructured formulations, which may result in a new avenue of using plant extracts and isolated compounds. Full article

Background/Objectives: Biocontrol agents (BCAs) are gaining attention as sustainable alternatives to chemical pesticides. Understanding their molecular mechanisms is crucial for improving plant protection. This study investigates the genomic features of Meyerozyma guilliermondii CECT13190, a promising BCA, to identify key genes involved in its biocontrol abilities. Methods: Whole-genome sequencing of M. guilliermondii was performed, followed by bioinformatics analysis to identify genes and pathways related to biocontrol, including gene copy number variation (CNV) analysis. Gene ontology (GO) analysis was conducted to examine gene functions, and a comparative proteomics approach assessed the presence and role of proteins in the secretome of M. guilliermondii. Results: Genomic analysis revealed key biocontrol-related pathways. CNV analysis indicated a direct correlation between gene amplification and competitive fitness, with seven genes showing gains and five genes showing losses. GO analysis identified categories such as enzymes, transcription factors, ribosomal and proteasomal complexes, transporters, membrane proteins, RNA processing, and stress-response-related proteins. Secretome analysis identified HSP70 and HSP90 as potential effectors involved in biocontrol activity. Conclusions: This study provides insights into the genomic features of M. guilliermondii and its biocontrol potential. The identification of genes involved in the stress response and the secretome highlights the multifaceted mechanisms through which M. guilliermondii antagonizes plant pathogens. Practical outcomes include the identification of candidate genes and proteins, such as HSP70 and HSP90, which can be targeted to enhance biocontrol efficiency in agricultural applications. Additionally, the observed CNVs offer a potential avenue for strain improvement programs to optimize competitiveness and efficacy in field conditions. Full article

Meyerozyma guilliermondii is an interesting oleaginous yeast with considerable potential for biotechnological applications. This yeast demonstrates the ability to utilize palm acid oil (PAO), a low-cost and renewable feedstock, as a carbon source, making it a sustainable candidate for single-cell oil production. Under optimal conditions with 4% of PAO, M. guilliermondii can accumulate lipids to approximately 45% of its cell dry weight (CDW). Notably, the expression level of PEX14, a gene associated with peroxisomal biogenesis, increases with higher PAO concentrations, coinciding with the formation of multiple small lipid bodies. These findings highlight the metabolic adaptability of M. guilliermondii and its potential for industrial lipid production using waste-derived feedstocks. Full article

This study is the first to investigate the impact of indigenous non-Saccharomyces yeasts, including Hypopichia pseudoburtonii, Metschnikowia sinensis/shanxiensis, Metschnikowia chrysoperlae, Metschnikowia pulcherrima, Lachancea thermotolerans, Hanseniaspora uvarum, Hanseniaspora guilliermondii, Hanseniaspora pseudoguilliermondii, Pichia kluyveri, and Starmerella apicola on the lipid composition of sterile Maraština grape juice and wines using the UHPLC-MS/MS method. Yeasts were tested in monoculture and sequential fermentations alongside commercial Saccharomyces cerevisiae. Indigenous non-Saccharomyces yeasts showed the potential to improve fermentation performance and enable the development of new wine styles through the biosynthesis of an unsaturated fatty acid pathway, which was identified as the most significant pathway. In monoculture fermentations, L. thermotolerans, H. uvarum, H. guilliermondii, H. pseudoguilliermondii, and P. kluyveri significantly reduced lignoceric acid, potentially influencing wine aroma through the formation of esters and higher alcohols. Hyp. pseudoburtonii, M. chrysoperlae, M. pulcherrima, P. kluyveri, and S. apicola increased the demand for lipids, such as stearic acid, which may help preserve membrane permeability by integrating into the membrane in response to ethanol shock. The most significant impact on free fatty esters was observed in fermentations with H. pseudoguilliermondii. Furthermore, L. thermotolerans in sequential fermentations significantly reduced arachidic, stearic, and palmitic acid. P. kluyveri reduced the content of erucic and linoleic acid. Full article

Apples and strawberries hold significant commercial and nutritional value but face pre- and post-harvest spoilage due to infections by Botrytis cinerea. While spoilage is conventionally managed using synthetic chemicals, there is a growing interest in utilising yeasts as biological control agents. This study aimed to assess the antifungal potential of non-Saccharomyces yeasts Suhomyces pyralidae, Meyerozyma guilliermondii, Pichia kluyveri, Zygoascus hellenicus, and Aureobasidium melanogenum against three B. cinerea strains (B05.10, IWBT-FF1, and PPRI 30807) on agar plates and in post-harvest trials on apples and strawberries. Aureobasidium melanogenum exhibited a broad range of extracellular enzyme production and inhibition rates of 55%, 52%, and 40% against the strains. In volatile organic compound (VOC) assays, P. kluyveri and S. pyralidae achieved 79% and 56% inhibition, respectively, with VOCs like isobutanol, isoamyl alcohol, 2-phenylethanol, isoamyl acetate, and 2-phenethyl acetate identified. In post-harvest trials, S. pyralidae was most effective on apples, with inhibition rates up to of 64%. The commercial fungicide Captan and S. pyralidae and P. kluyveri achieved 100% inhibition against the B. cinerea strains B05.10 and IWBT-FF1 on strawberries. These findings highlight the potential of the selected yeast species as biological control agents against B. cinerea, warranting further research into their application in commercial fruit protection. Full article