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Pathogens (Basel, Switzerland) Aug 2022Atypical spp. infections are rising, mostly due to the increasing numbers of immunocompromised patients. The most common spp. is still ; however, in the last decades,... (Review)
Review
Atypical spp. infections are rising, mostly due to the increasing numbers of immunocompromised patients. The most common spp. is still ; however, in the last decades, there has been an increase in non- species infections (e.g., , , and ). Furthermore, in the last 10 years, the reports on uncommon yeasts, such as , or , have also worryingly increased. This review summarizes the information, mostly related to the last decade, regarding the infections, diagnosis, treatment, and resistance of these uncommon species. In general, there has been an increase in the number of articles associated with the incidence of these species. Additionally, in several cases, there was a suggestive antifungal resistance, particularly with azoles, which is troublesome for therapeutic success.
PubMed: 36145394
DOI: 10.3390/pathogens11090963 -
Biotechnology For Biofuels 2020An economically viable production of biofuels and biochemicals from lignocellulose requires microorganisms that can readily convert both the cellulosic and...
BACKGROUND
An economically viable production of biofuels and biochemicals from lignocellulose requires microorganisms that can readily convert both the cellulosic and hemicellulosic fractions into product. The yeast displays a high capacity for uptake and conversion of several lignocellulosic sugars including the abundant pentose d-xylose, an underutilized carbon source since most industrially relevant microorganisms cannot naturally ferment it. Thus, constitutes an important source of knowledge and genetic information that could be transferred to industrial microorganisms such as to improve their capacity to ferment lignocellulose-derived xylose.
RESULTS
To understand the genetic determinants that underlie the metabolic properties of , we sequenced the genomes of both the in-house-isolated strain CBS 141442 and the reference strain PYCC 4715. De novo genome assembly and subsequent analysis revealed to be a haploid species belonging to the CTG clade of yeasts. The two strains have highly similar genome sizes and number of protein-encoding genes, but they differ on the chromosomal level due to numerous translocations of large and small genomic segments. The transcriptional profiles for CBS 141442 grown in medium with either high or low concentrations of glucose and xylose were determined through RNA-sequencing analysis, revealing distinct clusters of co-regulated genes in response to different specific growth rates, carbon sources and osmotic stress. Analysis of the genomic and transcriptomic data also identified multiple xylose reductases, one of which displayed dual NADH/NADPH co-factor specificity that likely plays an important role for co-factor recycling during xylose fermentation.
CONCLUSIONS
In the present study, we performed the first genomic and transcriptomic analysis of and identified several novel genes for conversion of xylose. Together the results provide insights into the mechanisms underlying saccharide utilization in and reveal potential target genes to aid in xylose fermentation in .
PubMed: 32190113
DOI: 10.1186/s13068-020-1663-9 -
Applied Microbiology and Biotechnology Feb 2019The development of robust microorganisms that can efficiently ferment both glucose and xylose represents one of the major challenges in achieving a cost-effective...
The development of robust microorganisms that can efficiently ferment both glucose and xylose represents one of the major challenges in achieving a cost-effective lignocellulosic bioethanol production. Candida intermedia is a non-conventional, xylose-utilizing yeast species with a high-capacity xylose transport system. The natural ability of C. intermedia to produce ethanol from xylose makes it attractive as a non-GMO alternative for lignocellulosic biomass conversion in biorefineries. We have evaluated the fermentation capacity and the tolerance to lignocellulose-derived inhibitors and the end product, ethanol, of the C. intermedia strain CBS 141442 isolated from steam-exploded wheat straw hydrolysate. In a mixed sugar fermentation medium, C. intermedia CBS 141442 co-fermented glucose and xylose, although with a preference for glucose over xylose. The strain was clearly more sensitive to inhibitors and ethanol when consuming xylose than glucose. C. intermedia CBS 141442 was also subjected to evolutionary engineering with the aim of increasing its tolerance to inhibitors and ethanol, and thus improving its fermentation capacity under harsh conditions. The resulting evolved population was able to ferment a 50% (v/v) steam-exploded wheat straw hydrolysate (which was completely inhibitory to the parental strain), improving the sugar consumption and the final ethanol concentration. The evolved population also exhibited a better tolerance to ethanol when growing in a xylose medium supplemented with 35.5 g/L ethanol. These results highlight the potential of C. intermedia CBS 141442 to become a robust yeast for the conversion of lignocellulose to ethanol.
Topics: Bioreactors; Candida; Ethanol; Fermentation; Glucose; Lignin; Xylose
PubMed: 30498977
DOI: 10.1007/s00253-018-9528-x -
Journal of Fungi (Basel, Switzerland) Dec 2020Candidiasis caused by species of the complex ( and ) and closely related species, and are increasing. These species often show reduced susceptibility to antifungal...
Candidiasis caused by species of the complex ( and ) and closely related species, and are increasing. These species often show reduced susceptibility to antifungal drugs, such as azoles and amphotericin B or, less frequently, echinocandins. However, conventional phenotypic identification methods are unable to accurately differentiate these species and, therefore, their prevalence may have been underestimated. In this study, 150 isolates that were probably misidentified were reanalyzed using two novel PCR approaches. We found that one isolate previously identified in 1996 as was , being one of the oldest isolates of this species described to date. We also found that this isolate had reduced susceptibility to fluconazole, itraconazole, and amphotericin B.
PubMed: 33348882
DOI: 10.3390/jof6040374 -
Microorganisms May 2022The aim of this study was to reveal the sites of yeast contamination in dairy production and perform taxonomic characterization of potential yeast spoilers in cheese...
The aim of this study was to reveal the sites of yeast contamination in dairy production and perform taxonomic characterization of potential yeast spoilers in cheese making. Occurrence of spoilage yeasts was followed throughout the manufacture of white-brined cheese at a Danish dairy, including the areas of milk pasteurization, curd processing, and packaging (26 sites in total). Spoilage yeasts were isolated from whey, old cheese curd, and air samples in viable counts of 1.48-6.27 log CFU/mL, 5.44 log CFU/g, and 1.02 log CFU/m, respectively. Yeast isolates were genotypically classified using (GTG)-PCR fingerprinting and identified by sequencing of the D1/D2 region of the 26S rRNA gene. The largest yeast heterogeneity was found in old curd collected under the turning machine of molds, where 11 different yeast species were identified. The most frequently isolated yeast species were , , and . The less abundant yeast species included , , , , , , , , , and . The awareness on occurrence and taxonomy of spoilage yeasts in cheese production will contribute to a knowledge-based control of contaminating yeasts and quality management of cheese at the dairies.
PubMed: 35744597
DOI: 10.3390/microorganisms10061079 -
Veterinary World Aug 2017This study was designed to isolate and identify yeast species from milk and meat products, and to test their antimicrobial activity against some bacterial species.
AIM
This study was designed to isolate and identify yeast species from milk and meat products, and to test their antimicrobial activity against some bacterial species.
MATERIALS AND METHODS
A total of 160 milk and meat products samples were collected from random sellers and super markets in New Damietta city, Damietta, Egypt. Samples were subjected to yeast isolation procedures and tested for its antimicrobial activity against , , and . In addition, all yeast species isolates were subjected to polymerase chain reaction (PCR) for detection of (kievitone hydratase) and (pectate degrading enzyme)genes.
RESULTS
The recovery rate of yeasts from sausage was 20% (2/10) followed by kareish cheese, processed cheese, and butter 10% (1/10) each as well as raw milk 9% (9/100), and fruit yoghurt 30% (6/20). Different yeast species were recovered, namely, (5 isolates), (4 isolates), (3 isolates), (2 isolates), (2 isolates), and (1 isolate). gene was detected in all isolates, however, gene was not detected in all identified yeast species. Antimicrobial activity of recovered yeasts against the selected bacterial species showed high activity with against and , against , and against . Moderate activities were obtained with , , and against ; meanwhile, all the tested yeasts revealed a very low antimicrobial activity against .
CONCLUSION
The obtained results confirmed that some kinds of yeasts have the ability to produce antimicrobial compounds that could inhibit some pathogenic and spoilage bacteria and these antimicrobial activity of yeasts enables them to be one of the novel agents in controlling spoilage of food.
PubMed: 28919693
DOI: 10.14202/vetworld.2017.979-983 -
Applied Biochemistry and Biotechnology May 2018Yeasts are good candidates to utilize the hydrolysates of lignocellulose, the most abundant bioresource, for bioproducts. This study aimed to evaluate the efficiencies...
Yeasts are good candidates to utilize the hydrolysates of lignocellulose, the most abundant bioresource, for bioproducts. This study aimed to evaluate the efficiencies of single-cell protein (SCP) and xylitol production by a novel yeast strain, Candida intermedia FL023, from lignocellulosic hydrolysates and xylose. This strain efficiently assimilated hexose, pentose, and cellubiose for cell mass production with the crude protein content of 484.2 g kg dry cell mass. SCP was produced by strain FL023 using corncob hydrolysate and urea as the carbon and nitrogen sources with the dry cell mass productivity 0.86 g L h and the yield of 0.40 g g sugar. SCP was also produced using NaOH-pretreated Miscanthus sinensis straw and corn steep liquor as the carbon and nitrogen sources through simultaneous saccharification and fermentation with the dry cell productivity of 0.23 g L h and yield of 0.17 g g straw. C. intermedia FL023 was tolerant to 0.5 g L furfural, acetic acid, and syringaldehyde in xylitol fermentation and produced 45.7 g L xylitol from xylose with the productivity of 0.38 g L h and the yield of 0.57 g g xylose. This study provides feasible methods for feed and food additive production from the abundant lignocellulosic bioresources.
Topics: Candida; Fungal Proteins; Lignin; Xylitol; Xylose
PubMed: 29098561
DOI: 10.1007/s12010-017-2644-8 -
FEMS Yeast Research Jan 2023Genome-editing toolboxes are essential for the exploration and exploitation of nonconventional yeast species as cell factories, as they facilitate both genome studies...
Genome-editing toolboxes are essential for the exploration and exploitation of nonconventional yeast species as cell factories, as they facilitate both genome studies and metabolic engineering. The nonconventional yeast Candida intermedia is a biotechnologically interesting species due to its capacity to convert a wide range of carbon sources, including xylose and lactose found in forestry and dairy industry waste and side-streams, into added-value products. However, possibilities of genetic manipulation have so far been limited due to lack of molecular tools for this species. We describe here the development of a genome editing method for C. intermedia, based on electroporation and gene deletion cassettes containing the Candida albicans NAT1 dominant selection marker flanked by 1000 base pair sequences homologous to the target loci. Linear deletion cassettes targeting the ADE2 gene originally resulted in <1% targeting efficiencies, suggesting that C. intermedia mainly uses nonhomologous end joining for integration of foreign DNA fragments. By developing a split-marker based deletion technique for C. intermedia, we successfully improved the homologous recombination rates, achieving targeting efficiencies up to 70%. For marker-less deletions, we also employed the split-marker cassette in combination with a recombinase system, which enabled the construction of double deletion mutants via marker recycling. Overall, the split-marker technique proved to be a quick and reliable method for generating gene deletions in C. intermedia, which opens the possibility to uncover and enhance its cell factory potential.
Topics: Gene Editing; Saccharomycetales; Homologous Recombination; Candida albicans; CRISPR-Cas Systems
PubMed: 36893808
DOI: 10.1093/femsyr/foad016 -
Archives of Razi Institute Apr 2022Opportunistic yeasts, such as and species (spp.), are reported to cause high rates of morbidity and mortality in immunocompromised and underlying patients. This study...
Opportunistic yeasts, such as and species (spp.), are reported to cause high rates of morbidity and mortality in immunocompromised and underlying patients. This study was conducted to investigate the phenotypic and genotypic identification of yeast spp. isolated from diabetic patients in Al-Najaf province, Iraq. Samples were collected from the depth of diabetic foot patients' wounds. They were then cultured on Sabouraud Dextrose Agar (SDA) and incubated at 30°C to 35°C for 5 to 7 days for the growth of yeast spp. The colonies were identified based on their microscopic features. Afterward, these yeast samples were cultured in CHROMagar for the isolation and identification of yeast spp. All collected samples were cultured on the SDA through the use of CHROMagar, which is considered a differential agar since the colonies obtained from and appear in different colors on this media. The Polymerase Chain Reaction assay was performed to amplify the internal transcribed spacer 1 (ITS1) and Internal transcribed spacer 4 (ITS4) sequences for the identification of the yeast spp. Furthermore, the products were sequenced by the Sanger method and compared to the reference global sequences in the national center for biotechnology information Gene Bank. The results showed different molecular sizes of the ITS regions of yeast spp. The primer pair was used for the same sample (i.e., ITS1-ITS4) and targeted the ITS regions. Yeast spp. can be considered the most common fungal agent of life-threatening invasive infections in patients with severe immunodeficiency or underlying diseases, and the treatment of these infections requires long stays in the intensive care units.
Topics: Agar; Culture Media; Diabetes Mellitus; Diabetic Foot; Glucose; Iraq; Phylogeny; Humans
PubMed: 36284947
DOI: 10.22092/ARI.2022.357104.1975 -
Genome Announcements Apr 2017Sustainable biofuel production from lignocellulosic materials requires efficient and complete use of all abundant sugars in the biomass, including xylose. Here, we...
Sustainable biofuel production from lignocellulosic materials requires efficient and complete use of all abundant sugars in the biomass, including xylose. Here, we report on the genome assemblies of two strains of the xylose-fermenting yeast : CBS 141442 and PYCC 4715.
PubMed: 28385851
DOI: 10.1128/genomeA.00138-17