Candida Guilliermondii Research Articles

Lawsonia inermis plant-based cobalt oxide nanoparticles: Synthesis, characterization and their biological studies

In the current study synthesized Cobalt oxide nanoparticles (Co3O4 NPs) using Lawsonia inermis plant extract as fuel. The synthesized Co3O4 NPs were characterized using UV–visible spectroscopy, DLS, FT-IR, XRD, FESEM, and EDX analysis. The synthesized Co3O4 NPs were confirmed by the XRD analysis and their average size was determined using DLS and FESEM analysis. The average size of the cobalt oxide nanoparticles obtained from FESEM analysis was found to be around 98 nm and strong signals of cobalt were captured in EDX images. The synthesized Co3O4 NPs were tested on bacterial and fungal strains of three concentrations viz 50, 100 and 170 ppm. An increase in the concentration of Co3O4 NPs shows potent antibacterial and antifungal activities. The higher concentration (170 ppm) showed good antimicrobial activity on all strains of bacteria and fungi than the lower concentrations (50 and 100 ppm) of Co3O4 NPs. The observed zone of inhibition values against all bacteria and fungi ranged from 0.3 to 3.0 mm and 20 ± 0.42 mm to 0.3 to 2.9 mm, respectively. Among them, Staphylococcus and Streptococcus aureus showed more zones of inhibition at 170 ppm concentration. Meyerozyma guilliermondii fungal strain showed more zone of inhibition at 170 ppm concentration.

Sow reproductive and progeny growth performance when fed Pichia guilliermondii yeast postbiotic: systematic review and meta-analysis.

Previous research suggested that feeding sows with a product containing an inactivated strain specific Pichia guilliermondii yeast postbiotic (PG; Citristim, ADM Animal Nutrition, Quincy, IL) has the potential to support fecundity, and progeny performance at birth, weaning, and after weaning. To summarize these effects, a systematic review followed by a meta-analysis was carried out to determine the effects of feeding sows with PG during gestation and lactation on reproductive the performance of sows and the growth of progeny after weaning. All experiments included were randomized trials reporting side-by-side comparisons of an appropriate control (CON) and the CON with the inclusion of PG. The effects of PG inclusion in sow diets were evaluated using the raw mean difference and effect size calculations. Analysis included seven trials for sow reproductive and litter performance until weaning, and eight trials for progeny performance after weaning. The risk of publication bias was assessed by funnel plots. In the case of publication bias, the Trim and Fill method was used. Heterogeneity was assessed using I 2 statistics. Sows fed PG during gestation and lactation had more piglets born alive (BA), BA + stillborn, and BA + stillborn + mummies (P < 0.001). The individual birth weight of the piglets was not affected by the supplementation (P = 0.835). As a result, litter weight at birth was greater in sows-fed PG (P < 0.001). Piglets born from PG-fed sows tended to be weaned 0.34 d younger than those from CON-fed sows (P = 0.060). Twenty-one-day adjusted pig weight at weaning tended to be lighter by 0.122kg in the PG sow group (P = 0.069); however, litter weight at weaning adjusted to 21 d remained similar across groups (P = 0.516). The number of piglets weaned and mortality-adjusted number of piglets weaned per sow were greater in PG than in CON sows (P < 0.023). A carryover effect was observed for progeny of PG-fed sows after weaning. Piglets born from PG-supplemented sows had greater weight gain (P = 0.030) and tended to have a better survival rate (P = 0.055) until the end of the nursery phase. These results indicate that feeding PG to sows during gestation and lactation consistently and significantly improves not only the performance of sows at farrowing but also performance of the progeny after weaning.

Features of the rare pathogen Meyerozyma guilliermondii strain SO and comprehensive in silico analyses of its adherence-contributing virulence factor agglutinin-like sequences

Meyerozyma guilliermondii is a rare yeast pathogen contributing to the deadly invasive candidiasis. M. guilliermondii strain SO, as a promising protein expression host, showed 99% proteome similarity with the clinically isolated ATCC 6260 (type strain) in a recent comparative genomic analysis. However, their in vitro virulence features and in vivo pathogenicity were uncharacterized. This study aimed to characterize the in vitro and in vivo pathogenicity of M. guilliermondii strain SO and analyze its Als proteins (MgAls) via comprehensive bioinformatics approaches. M. guilliermondii strain SO showed lower and higher sensitivity towards β-mercaptoethanol and lithium, respectively than the avirulent S. cerevisiae but exhibited the same tolerance towards cell wall-perturbing Congo Red with C. albicans. With 7.5× higher biofilm mass, M. guilliermondii strain SO also demonstrated 75% higher mortality rate in the zebrafish embryos with a thicker biofilm layer on the chorion compared to the avirulent S. cerevisiae. Being one of the most important Candida adhesins, sequence and structural analyses of four statistically identified MgAls showed that MgAls1056 was predicted to exhibit the most conserved amyloid-forming regions, tandem repeat domain and peptide binding cavity (PBC) compared to C. albicans Als3. Favoured from the predicted largest ligand binding site and druggable pockets, it showed the highest affinity towards hepta-threonine. Non-PBC druggable pockets in the most potent virulence contributing MgAls1056 provide new insights into developing antifungal drugs targeting non-albicans Candida spp. Virtual screening of available synthetic or natural bioactive compounds and MgAls1056 deletion from the fungal genome should be further performed and validated experimentally. Communicated by Ramaswamy H. Sarma

Screening and characterization of indigenous non-Saccharomyces cerevisiae with high enzyme activity for kiwifruit wine production

To explore the diversity and fermentation potential of non-Saccharomyces cerevisiae associated with kiwifruit, indigenous yeasts isolated from kiwifruit and natural fermentation were comprehensively analyzed. A total of 166 indigenous yeasts were isolated, of which 54 representative strains were used for subsequent enzyme activity characterization. Different colorimetric methods were used to verify the ability of these strains to secrete hydrolytic enzymes, and then six strains were selected for sequential fermentation by specific activity assay. The performance of indigenous yeasts in improving organic acids, polyphenols, volatile compounds and sensory characteristics of wines was evaluated holistically. Results indicated that most sequential fermentations exhibited significant improvements in vitamin C and polyphenols. Remarkably, the involvement of Zygosaccharomyces rouxii, Meyerozyma guilliermondii, and Pichia kudriavzevii increased the concentrations of ethyl esters, acetates and alcohols, enhancing floral and tropical fruit odors and ultimately achieving the highest overall sensory acceptability, thereby highlighting their potential in kiwifruit wine fermentation.

Beneficial Interactive Effects Provided by an Arbuscular Mycorrhizal Fungi and Yeast on the Growth of Oenothera picensis Established on Cu Mine Tailings

Phytoremediation, an environmentally friendly and sustainable approach for addressing Cu-contaminated environments, remains underutilized in mine tailings. Arbuscular mycorrhizal fungi (AMF) play a vital role in reducing Cu levels in plants through various mechanisms, including glomalin stabilization, immobilization within fungal structures, and enhancing plant tolerance to oxidative stress. Yeasts also contribute to plant growth and metal tolerance by producing phytohormones, solubilizing phosphates, generating exopolysaccharides, and facilitating AMF colonization. This study aimed to assess the impact of AMF and yeast inoculation on the growth and antioxidant response of Oenothera picensis plants growing in Cu mine tailings amended with compost. Plants were either non-inoculated (NY) or inoculated with Meyerozyma guilliermondii (MG), Rhodotorula mucilaginosa (RM), or a combination of both (MIX). Plants were also inoculated with Claroideoglomus claroideum (CC), while others remained non-AMF inoculated (NM). The results indicated significantly higher shoot biomass in the MG-NM treatment, showing a 3.4-fold increase compared to the NY-NM treatment. The MG-CC treatment exhibited the most substantial increase in root biomass, reaching 5-fold that in the NY-NM treatment. Co-inoculation of AMF and yeast influenced antioxidant activity, particularly catalase and ascorbate peroxidase. Furthermore, AMF and yeast inoculation individually led to a 2-fold decrease in total phenols in the roots. Yeast inoculation notably reduced non-enzymatic antioxidant activity in the ABTS and CUPRAC assays. Both AMF and yeast inoculation promoted the production of photosynthetic pigments, further emphasizing their importance in phytoremediation programs for mine tailings.

Plant Defence Induction by Meyerozyma guilliermondii in Vitis vinifera L.

This article emphasizes the crucial importance of yeast Meyerozyma guilliermondii (Patent CECT13190) as a biological control agent (BCA) in eliciting defensive responses in vine plants, and is supported by comprehensive physiological, proteomic, and transcriptomic analyses. The results demonstrate that the BCA M. guilliermondii can induce enhanced defensive responses, as reflected in the regulation of key proteins. Notably, the upregulated expression of calmodulin and pathogenesis-related protein 10 (PR-10) are indicative of a complex interplay between calcium signalling, salicylic acid accumulation, and the elicitation of plant defence responses against pathogens. Furthermore, changes in microtubule dynamics and proteins related to protein synthesis and folding are observed, confirming the elicitation of defence responses. The correspondence between proteomic and transcriptomic analyses for genes codifying pathogenesis-related proteins, such as Vcgns1, VviTL1, and Vcchit1b, reinforces the empirical robustness of our findings. Collectively, our research explores the modulation of plant defences by the BCA, opening promising avenues for innovative agricultural strategies that enhance crop resilience and productivity.

PSXI-27 Live Yeasts Enhance Ruminal Fermentation of Fibrous Feedstuffs

Abstract Since the beginning of the present century, research results have shown that ruminant researchers have explored the idea of manipulate ruminal fermentation, trying to improve a much better metabolism of nutrients in the rumen, all of this with the aim to increase the productivity of ruminants. The main goal of this experiment was to evaluate the potential use of a savage yeast strain (Pichia guilliermondii) on the ruminal fermentation of maize stover. To accomplish the objective two in vitro treatments were examined: a) filtered rumen liquid + powdered maize stover + yeast-free culture medium, and b) filtered rumen liquid + powdered maize stover + culture medium inoculated with yeast. Samples were collected at different time, 0, 6, 12, and 24 h and examined for effects on culture pH, ammonia nitrogen (NH3-N), the fiber digestibility percentages of neutral detergent fiber (NDFD) and acid detergent fiber (ADFD), as well the digestibility of dry matter (DMD), and the concentration of volatile fatty acids (VFAs). The results showed that the addition of Levica 27 had no effect on the ruminal pH, NH3-N or the digestibility indicators (P &amp;gt; 0.05). However, at 12 h, the inclusion of Levica 27 increased (P &amp;lt; 0.05) the molar total of VFAs, and acetic and propionic acids in ruminal fluid and decreased (P &amp;lt; 0.05) the C2:C3 ratio. Our conclusion was that Pichia guilliermondii had a stimulating effect on the in vitro ruminal fermentation over a range within 6 and 12 h, a result that should be taken into account when in vivo studies are replicated with this yeast strain.

Fermentation with a multi-strain to enhance the flavor of HongJun Tofu, a Chinese fermented okara food

Traditional HongJun Tofu typically possesses a single flavor, probably because it is fermented primarily by only one fungus — Neurospora crassa (OM009248). Multi-strains could help in enriching the flavor of fermented products. Accordingly, Lactiplantibacillus plantarum (MT538590.1) and Meyerozyma guilliermondii (KX385855.1) were chosen to co-ferment with N. crassa to enhance the flavor of HongJun Tofu. In this study, HongJun Tofu fermented with multi-strains (L. plantarum, M. guilliermondii and N. crassa) demonstrated lower relative aroma activity values of beany. Moreover, the main flavor compounds of HongJun Tofu fermented with multi-strains exhibited fruity, mushroomy, floral, and nutty flavors. Meanwhile, HongJun Tofu fermented with multi-strains showed reduced bitterness, increased freshness, and richer taste without sourness. Results indicated that L. plantarum and M. guilliermondii played a beneficial role in enriching the flavor of HongJun Tofu and did not lead to the deterioration of the flavor. This work provided a reference method for improving the flavor of HongJun Tofu and facilitated its commercial production.

Biodegradation of patulin in fresh pear juice by an aldo-keto reductase from Meyerozyma guilliermondii

Bio-enzymes have shown broad application prospects in controlling mycotoxins due to their strong specificity, fast reaction rate and mild reaction conditions. However, the number of enzymes isolated, purified and characterized to degrade patulin (PAT) is limited. We expressed an aldo-keto reductase (MgAKR) from Meyerozyma guilliermondii in Escherichia coli. The results demonstrated that the purified MgAKR could convert PAT into ascladiol in vitro with NADPH serving as a coenzyme. Adding 300 μg/mL MgAKR resulted in an 88 % reduction of PAT in fresh pear juice without affecting its quality in the biodegradation process. The site-directed mutagenesis suggested that the interaction between MgAKR and PAT occurred through the active sites of Lys242 and Leu240. This study serves as a valuable theoretical reference for the development of enzymes aimed at detoxifying PAT in fruit and their derivatives.

Exploring the Profile Contributions in Meyerozyma guilliermondii YB4 under Different NaCl Concentrations Using GC-MS Combined with GC-IMS and an Electronic Nose.

Using Meyerozyma guilliermondii YB4, which was isolated and screened from southern Sichuan pickles in the laboratory, as the experimental group, we investigated the changes in growth, total ester content, and volatile flavor substances of M. guilliermondii YB4 under different NaCl concentrations. The growth of M. guilliermondii YB4 was found to be inhibited by NaCl, and the degree of inhibition increased at higher NaCl concentrations. Additionally, the total ester content of the control group (CK) was significantly lower compared to the other groups (p < 0.05). The application of NaCl also resulted in distinct changes in the volatile profile of YB4, as evidenced by E-nose results. Gas chromatography-mass spectrometry (GC-MS) and gas chromatography-ion mobility spectrometry (GC-IMS) were employed to analyze the volatile compounds. A total of 148 and 86 volatiles were detected and identified using GC-MS and GC-IMS, respectively. Differential volatiles among the various NaCl concentrations in YB4 were determined by a variable importance in projection (VIP) analysis in partial least squares-discriminant analysis (PLS-DA). These differentially expressed volatiles were further confirmed by their relative odor activity value (ROAV) and odor description. Ten key contributing volatiles were identified, including ethanol, 1-pentanol, nonanal, octanal, isoamyl acetate, palmitic acid ethyl ester, acrolein, ethyl isobutanoate, prop-1-ene-3,3'-thiobis, and 2-acetylpyrazine. This study provides insights into the specificities and contributions of volatiles in YB4 under different NaCl concentrations. These findings offer valuable information for the development of aroma-producing yeast agents and the subsequent enhancement in the flavor of southern Sichuan pickles.

Non-Saccharomyces Yeasts from Organic Vineyards as Spontaneous Fermentation Agents.

Currently, non-Saccharomyces yeasts are the subject of interest, among other things, for their contribution to the aromatic complexity of wines. In this study, the characterisation of non-Saccharomyces yeasts was addressed by their isolation during spontaneous fermentations of organic Verdejo grapes, obtaining a total of 484 isolates, of which 11% were identified by molecular techniques as non-Saccharomyces yeasts. Fermentative isolates belonging to the species Hanseniaspora meyeri, Hanseniaspora osmophila, Pichia guilliermondii, Pichia kudriavzevii, Torulaspora delbrueckii, and Wickerhamomyces anomalus were analysed. Significant differences were found in the yeast populations established at the different fermentation stages. Interestingly, W. anomalus stood up as a widely distributed species in vineyards, vintages, and fermentation stages. Several of the strains studied stood out for their biotechnological potential in the production of Verdejo wine, showing the presence of relevant enzymatic activity for the release of varietal aromas and the technological improvement of the winemaking process. Three enzymatic activities were found in an important number of isolates, β-glucosidase, protease, and β-lyase, implicated in the positive aromatic impact on this style of white wine. In that sense, all the isolates of W. anomalus presented those activities. T. delbrueckii isolates were highlighted for their significant β-lyase activity. In addition, T. delbrueckii was outlined because of its potential to achieve an elevated fermenting power, as well as the lack of lag phase. The results obtained highlight the importance of maintaining the microbial diversity that contributes to the production of wines with unique and distinctive characteristics of the production region.

The role of fruits as reservoirs for resistant and virulent strains of opportunistic yeasts.

Strains of the Candida parapsilosis and Meyerozyma guilliermondii species complexes isolated from the internal tissues of 26 fruit species from 21 countries were evaluated for their susceptibility to conventional antifungal compounds (fluconazole, voriconazole, amphotericin B) and hydrolytic activity. A total of 144 strains were studied. Resistance to at least one of the antifungal compounds tested was found in 26.4% of the endophytic strains examined. Most of the strains were insensitive to fluconazole. Multiresistance was detected only in two strains of C. parapsilosis sensu stricto from tropical apples. Phospholipase production and proteolytic and hemolytic activities were significantly higher in endophytes from tropical fruits. Resistant and virulent strains of opportunistic yeasts can thus spread worldwide via purchased fruit, which can harm people with a weakened immune status and children whose immune systems are not yet fully developed.

The Use of Thioflavin T for the Estimation and Measurement of the Plasma Membrane Electric Potential Difference in Different Yeast Strains.

The use of the cationic, dye thioflavin T (ThT), to estimate the electric plasma membrane potential difference (PMP) via the fluorescence changes and to obtain its actual values from the accumulation of the dye, considering important correction factors by its binding to the internal components of the cell, was described previously for baker's yeast. However, it was considered important to explore whether the method developed could be applied to other yeast strains. Alternative ways to estimate the PMP by using flow cytometry and a multi-well plate reader are also presented here. The methods were tested with other strains of Saccharomyces cerevisiae (W303-1A and FY833), as well as with non-conventional yeasts: Debaryomyces hansenii, Candida albicans, Meyerozyma guilliermondii, and Rhodotorula mucilaginosa. Results of the estimation of the PMP via the fluorescence changes under different conditions were adequate with all strains. Consistent results were also obtained with several mutants of the main monovalent transporters, validating ThT as a monitor for PMP estimation.

Meyerozyma strains as biocontrol agents against postharvest phytopathogens of jackfruit (Artocarpus heterophyllus Lam.)

Jackfruit is a tropical fruit highly perishable due to phytopathogenic diseases, with up to 35% postharvest losses. Currently, the control of these diseases is sought through the use of natural alternatives such as biocontrol agents. Therefore, this work aimed to identify the phytopathogens affecting jackfruit in postharvest and to study the antagonism of Meyerozyma guilliermondii and Meyerozyma caribbica for disease control. Eight postharvest fungi were identified using morphological and molecular techniques; those with high pathogenicity were Lasiodiplodia theobromae, Rhizopus sp., and Neofusicoccum batangarum. Meyerozyma guilliermondii gave the highest mycelial inhibitions, 100, 96, and 90% against Rhizopus sp., L. theobromae, and N. batangarum, respectively. The lowest incidences of Rhizopus sp. decay were 22 and 32%, with M. guilliermondii and M. caribbica, respectively. Neofusicoccum batangarum was identified for the first time in Nayarit as a postharvest pathogen for jackfruit. Yeasts showed antagonistic effects against these phytopathogens with inhibitions higher than 68%.

Emergence of cryptic species and clades of Meyerozyma guilliermondii species complex exhibiting limited in vitro susceptibility to antifungals in patients with candidemia.

Members of the Meyerozyma guilliermondii species complex are able to cause superficial and life-threatening systemic infections with low susceptibility to azoles and echinocandins. We tested 130 bloodstream M. guilliermondii complex isolates collected from eight Latin American medical centers over 18 years (period 1 = 2000-2008 and period 2 = 2009-2018) to investigate trends in species distribution and antifungal resistance. The isolates were identified by rDNA ITS region sequencing, and antifungal susceptibility tests were performed against fluconazole, voriconazole, anidulafungin, and amphotericin B using the CLSI microbroth method. M. guilliermondii sensu stricto (s.s.; n = 116) was the most prevalent species, followed by Meyerozyma caribbica (n = 12) and Meyerozyma carpophila (n = 2). Based on rDNA ITS identification, three clades within M. guilliermondii sensu stricto were characterized (clade 1 n = 94; clade 2 n = 19; and clade 3 n = 3). In the second period of study, we found a substantial increment in the isolation of M. caribbica (3.4% versus 13.8%; P = 0.06) and clade 2 M. guilliermondii s.s. exhibiting lower susceptibility to one or more triazoles. IMPORTANCE Yeast-invasive infections play a relevant role in human health, and there is a concern with the emergence of non-Candida pathogens causing disease worldwide. There is a lack of studies addressing the prevalence and antifungal susceptibility of different species within the M. guilliermondii complex that cause invasive infections. We evaluated 130 episodes of M. guilliermondii species complex candidemia documented in eight medical centers over 18 years. We detected the emergence of less common species within the Meyerozyma complex causing candidemia and described a new clade of M. guilliermondii with limited susceptibility to triazoles. These results support the relevance of continued global surveillance efforts to early detect, characterize, and report emergent fungal pathogens exhibiting limited susceptibility to antifungals.

A Potentially Practicable Halotolerant Yeast Meyerozyma guilliermondii A4 for Decolorizing and Detoxifying Azo Dyes and Its Possible Halotolerance Mechanisms.

In this study, a halotolerant yeast that is capable of efficiently decolorizing and detoxifying azo dyes was isolated, identified and characterized for coping with the treatment of azo-dye-containing wastewaters. A characterization of the yeast, including the optimization of its metabolism and growth conditions, its detoxification effectiveness and the degradation pathway of the target azo dye, as well as a determination of the key activities of the enzyme, was performed. Finally, the possible halotolerance mechanisms of the yeast were proposed through a comparative transcriptome analysis. The results show that a halotolerant yeast, A4, which could decolorize various azo dyes, was isolated from a marine environment and was identified as Meyerozyma guilliermondii. Its optimal conditions for dye decolorization were ≥1.0 g/L of sucrose, ≥0.2 g/L of (NH4)2SO4, 0.06 g/L of yeast extract, pH 6.0, a temperature of 35 °C and a rotation speed of ≥160 rpm. The yeast, A4, degraded and detoxified ARB through a series of steps, relying on the key enzymes that might be involved in the degradation of azo dye and aromatic compounds. The halotolerance of the yeast, A4, was mainly related to the regulation of the cell wall components and the excessive uptake of Na+/K+ and/or compatible organic solutes into the cells under different salinity conditions. The up-regulation of genes encoding Ca2+-ATPase and casein kinase II as well as the enrichment of KEGG pathways associated with proteasome and ribosome might also be responsible for its halotolerance.

Multiple pathways involved in the Ca ascorbate-induced enhancement of Meyerozyma guilliermondii biocontrol efficacy

The external environment and yeast’s inherent physiological characteristics play important roles in the biocontrol efficacy of antagonistic yeast. Attention has been focused on increasing biocontrol efficacy by improving yeast environmental adaptability in recent years. In this study, the effect and mechanism of calcium ascorbate (Ca ascorbate) on enhancement of Meyerozyma guilliermondii biocontrol effectiveness were investigated based on transcriptome sequencing, and physiological and biochemical activity analysis of yeast cells. The results demonstrated that the yeast induced by 0.2 g/L Ca ascorbate inhibit gray decay substantially compared with the control, non-induced, ascorbic acid (VC) and calcium chloride (CaCl2) induced groups.The results of transcriptome sequencing showed that the differentially expressed genes (DEGs) of M. guilliermondii induced by Ca ascorbate were mainly enriched in those GO functions such as “cell process, metabolic process, antioxidant” and KEGG pathways such as “ribosome, metabolism, cell cycle”. Ca ascorbate induction could significantly upregulate the expression of genes related to ribosome synthesis (RIM101, PAN3, NHP2, and RPS19A), growth and metabolism (HXT2 and SDH4), and antioxidation (FMN1 and SNZ1). The accelerated growth dynamics and cell metabolic activity as well as the elevated antioxidant enzyme activity were all in line with the transcriptomic data. As expected, the increased antioxidant enzyme activity reduced the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA). These results demonstrated that the mechanism of Ca ascorbate-induced enhancement of biocontrol efficacy is related to accelerating yeast proliferation and colonization, improving nutrient utilization, enhancing cell homeostasis and cell wall structure, and improving the environmental adaptability of yeast cells. Additionally, Ca2+ also has a synergistic effect on yeast physiological activity and antioxidant activity to promote the improvement of yeast biocontrol efficacy.

Meyerozyma guilliermondii promoted the deposition of GSH type lignin by activating the biosynthesis and polymerization of monolignols at the wounds of potato tubers

Lignin is a crucial component in the wound tissue of tubers. The biocontrol yeast Meyerozyma guilliermondii increased the activities of phenylalanine ammonia lyase, cinnamate-4-hydroxylase, 4-coenzyme coenzyme A ligase, and cinnamyl alcohol dehydrogenase, and elevated the levels of coniferyl, sinapyl, and p-coumaryl alcohol. The yeast also enhanced the activities of peroxidase and laccase, as well as the content of hydrogen peroxide. The lignin promoted by the yeast was identified as guaiacyl-syringyl-p-hydroxyphenyl type using Fourier transform infrared spectroscopy and two-dimensional heteronuclear single quantum coherence nuclear magnetic resonance. Furthermore, a larger signal area for G2, G5, G'6, S2, 6, and S'2, 6 units was observed in the treated tubers, and the G'2 and G6 units were only detected in the treated tuber. Taken together, M. guilliermondii could promote deposition of guaiacyl-syringyl-p-hydroxyphenyl type lignin by activating the biosynthesis and polymerization of monolignols at the wounds of potato tubers.

Overexpression of the SDR gene improves the ability of Meyerozyma guilliermondii to degrade patulin in pears and juices.

The intracellular enzymes of antagonistic yeast are effective in controlling patulin (PAT) contamination. However, countless enzymes that have been revealed remain functionally uncharacterized. The study built on previous transcriptomic data obtained by our research group to amplify and express a gene encoding a short-chain dehydrogenase/reductase (SDR) in Meyerozyma guilliermondii. Overexpression of SDR increased the tolerance of M. guilliermondii to PAT and the ability to degrade PAT of the intracellular enzymes. Furthermore, MgSDR-overexpressed M. guilliermondii showed higher PAT degradation in juices (apple and peach) and controlled the blue mold of pears at 20°C and 4°C while significantly reduced the content of PAT and the biomass of Penicillium expansum in decayed tissues than wild-type M. guilliermondii. This study provides theoretical references for the subsequent heterologous expression, formulation, and application of the SDR protein from M. guilliermondii and contributes to elucidating the PAT degradation mechanism of antagonistic yeasts.

Distribution of fungemia agents in five years and antifungal resistance.

Recent research has suggested that fungemia may demonstrate an epidemiologic shift in etiologic agents. This study focuses on the agents causing fungemia and antifungal resistance in a tertiary hospital. We evaluated all-age fungemia cases admitted to Balikesir Ataturk City Hospital in 2017-2021. Blood cultures (BC) were studied using BacT/Alert® 3D (bioMérieux, Marcyl'Etoile, France) and Render BC128 System (Render Biotech Co. Ltd., Shenzhen, China). On the data, we explored only the first fungal positive samples or the first isolates in different episodes of the same patients. Upon The Clinical and Laboratory Standards Institute (CLSI) disk diffusion guidelines, conventional methods and the Phoenix™ 100 System (Becton Dickinson, Franklin Lakes, NJ, USA) were utilized for antifungal susceptibility identifications. The findings showed that 325 (0.84%) of 38,682 BC sets were positive for fungal growth. Except for four cases (1.2%) [Saprochaete capitata (n = 2); Trichosporon asahii (n = 1), and Saccharomyces cerevisiae (n = 1)], all positive cases yielded Candida spp. (98.8%) growth. In these patients, the following Candida spp. were isolated: Candida albicans complex (n = 155; 47.7%), Candida parapsilosis complex (n = 127; 39.1%), Candida glabrata complex (n = 19; 5.85%), Candida tropicalis (n = 12; 3.7%), Candida kefyr (n = 5; 1.54%), Candida krusei (n = 2; 0.62%), and Candida guilliermondii complex (n = 1; 0.31%). We also realized that while none of the Candida spp. had echinocandin resistance, 8 C. parapsilosis complex isolates were resistant to fluconazole, and 17 C. parapsilosis complex and 2 C. tropicalis isolates were susceptible dose-dependent to fluconazole. In brief, antifungal resistance is more likely to restrict therapeutic options, albeit it is, fortunately, not prevalent in Turkey despite a few recent reports. Yet, a robust detection or management of antifungal resistance requires species-level identification and strict compliance with relevant management guidelines. Besides, challenges in research may be compensated with a national data set built with data from local laboratories.