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Food Microbiology Sep 2022White colony-forming yeasts (WCFYs) have been reported to form a white colony on the surface of kimchi, resulting in the deterioration of kimchi sensory quality....
White colony-forming yeasts (WCFYs) have been reported to form a white colony on the surface of kimchi, resulting in the deterioration of kimchi sensory quality. However, toxicity of WCFY has rarely been studied. Thus, to evaluate the safety of WCFY (i.e., Kazachstania servazzii, Candia sake, and Pichia kudriavzevii), we conducted cell and animal experiments as well as genomic analysis. In vitro studies indicated that WCFY did not induce cytotoxic responses such as lactate dehydrogenase release, excessive oxidative stress, and mitochondrial damage at concentrations of up to 2.5 × 10 CFU/mL in human intestinal and liver cells. In animal studies using rats (single-dose and 14-day repeated-dose oral toxicity studies), WCFY did not induce death, clinical signs of toxicity, histological alterations of the liver, or increases in the expression of pro-inflammatory cytokines nor cytochrome P450-2E1 in liver tissue at concentrations of up to 5 × 10 CFU/head/day. Genomic analysis revealed that P. kudriavzevii did not harbor genes related to toxicity and antimicrobial resistance. Taken together, our data suggest that exposure to WCFY through kimchi intake did not induce toxic response in the Caco-2, HepG2, and Sprague-Dawley rats. The current work provides evidence for the safety of accidental major WCFY ingestion via kimchi.
Topics: Animals; Caco-2 Cells; Fermented Foods; Genomics; Humans; Rats; Rats, Sprague-Dawley; Yeasts
PubMed: 35690449
DOI: 10.1016/j.fm.2022.104057 -
Food Research International (Ottawa,... Feb 2020Guangxi Suansun (Guangxi SS) and Guangxi Suancai (Guangxi SC) are two kinds of traditionally fermented vegetables consumed as cooking ingredients in Guangxi Province,... (Comparative Study)
Comparative Study
Guangxi Suansun (Guangxi SS) and Guangxi Suancai (Guangxi SC) are two kinds of traditionally fermented vegetables consumed as cooking ingredients in Guangxi Province, China, for thousands of years. However, little is known about their microbial communities as well as the differences between them. Thus, this study was aimed to investigate and compare the physicochemical indexes as well as the bacterial and fungal profiles of Guangxi SS and Guangxi SC. Results showed that the titratable acidity, lactic acid and acetic acid content in SS were significantly higher than those in SC, while the salinity of SS was significantly lower than that in SC, and the nitrite contents in all samples were are far lower than the limit of nitrite contents in fermented vegetables. Firmicutes, Proteobacteria, Ascomycota and Basidiomycota were the main phyla observed in both SS and SC samples. Lactobacillus, Serratia, Stenotrophomonas and Lactococcus were the major bacterial genera in both SS and SC samples, the predominant fungal genera in SS group were Kazachstania, Debaryomyces and Pichia, while the major genera in SC group were Kazachstania, Debaryomyces and Nakaseomyces. At the species level, Lactobacillus acetotolerans, Pichia kudriavzevii, Debaryomyces hansenii, Pichia norvegensis, Kazachstania exigua and Kazachstania humilis were the major species observed in SS, while L. delbrueckii, L. fermentum, L. aviarius, and Pichia kudriavzevii and Debaryomyces hansenii were the predominant species in SC. Salinity was found to be more strongly correlated to the bacterial and fungal communities of both SS and SC than other physicochemical factors (pH, the titratable acidity, lactic acid and acetic acid content). This study provided detailed insight into the microbial communities of Guangxi SS and Guangxi SC, and the findings may help understand the microbial structures of Chinese traditional fermented vegetables.
Topics: Debaryomyces; Fermentation; Fermented Foods; Food Microbiology; Lactobacillus; Microbiota; Pichia; Saccharomycetales; Salinity; Vegetables; Zygosaccharomyces
PubMed: 31955789
DOI: 10.1016/j.foodres.2019.108755 -
American Journal of Physiology.... Apr 2022The gut microbiome has the capacity to regulate bone mass. The aim of this study was to develop a nutritional synbiotic dietary assemblage at an optimal dose to maintain...
The gut microbiome has the capacity to regulate bone mass. The aim of this study was to develop a nutritional synbiotic dietary assemblage at an optimal dose to maintain bone mass in ovariectomized (Ovx) mice. We performed genomic analyses and in vitro experiments in a large collection of bacterial and fungal strains (>4,000) derived from fresh fruit and vegetables to identify candidates with the synergistic capacity to produce bone-protective short-chain fatty acids (SCFA) and vitamin K2. The candidate SBD111-A, composed of , , , , and together with prebiotic dietary fibers, produced high levels of SCFA in vitro and protected against Ovx-induced trabecular bone loss in a dose-dependent manner in mice. Metagenomic sequencing revealed that SBD111-A changed the taxonomic composition and enriched specific pathways for synthesis of bone-protective SCFA, vitamin K2, and branched-chain amino acids in the gut microbiome. We performed genomic analyses and in vitro experiments in a collection of bacterial and fungal strains. We identified a combination (SBD111-A) that produced high levels of SCFA in vitro and protected against ovariectomy-induced bone loss in a dose-dependent manner in mice. Metagenomic sequencing revealed that SBD111-A changed the taxonomic composition and function of the gut microbiome and enriched pathways for synthesis of bone-protective SCFA, vitamin K2, and branched-chain amino acids.
Topics: Amino Acids, Branched-Chain; Animals; Bacteria; Cancellous Bone; Fatty Acids, Volatile; Female; Humans; Mice; Ovariectomy; Synbiotics; Vitamin K 2
PubMed: 35156423
DOI: 10.1152/ajpendo.00366.2021 -
Frontiers in Microbiology 2022The commercial active dry yeast strains used for cider production in China are far behind the requirements of the cider industry development in recent decades. In this...
The commercial active dry yeast strains used for cider production in China are far behind the requirements of the cider industry development in recent decades. In this study, eight yeasts, including , , , and , were screened and assessed by growth performance, methanol production, aroma analysis, and their transcriptive characterization. strains WFC-SC-071 and WFC-SC-072 were identified as promising alternatives for cider production. Strains WFC-SC-071 and WFC-SC-072 showed an excellent growth capacity characterized by 91.6 and 88.8% sugar utilization, respectively. Methanol production by both strains was below 200 mg/L. Key aroma compounds imparting cider appreciably characteristic aroma increased in cider fermented by strains WFC-SC-071 and WFC-SC-072. RT-qPCR analysis suggested that most genes associated with growth capacity, carbohydrate uptake, and aroma production were upregulated in WFC-SC-071 and WFC-SC-072. Overall, two strains are the optimal starters for cider production to enable the diversification of cider, satisfy the differences in consumer demand, and promote cider industry development.
PubMed: 36439849
DOI: 10.3389/fmicb.2022.1042613 -
Food & Function Apr 2023Postbiotics are attractive as alternatives to antibiotics for use against post-weaning diarrhea. However, their beneficial mechanisms are largely unknown. In the current...
Postbiotics are attractive as alternatives to antibiotics for use against post-weaning diarrhea. However, their beneficial mechanisms are largely unknown. In the current study, we first demonstrated that supplementation with 0.5% FZ12 postbiotics in the diet significantly reduced diarrhea incidence, promoted growth performance, improved gut health performance, and significantly enriched beneficial bacteria, particularly spp., in the intestines of weaned piglets. Importantly, we identified a heat- and proteinase K-sensitive component, cytochrome , of the postbiotics that significantly promoted the growth and biofilm formation of FP13. We demonstrated the importance of FZ12 postbiotics in improving the intestinal health of a model animal and revealed that cytochrome is one of the important components of yeast postbiotics. These findings may provide new insights into microbe-postbiotics interplay that can be applied to guidelines for dietary modulation to alleviate weaning-induced diarrhea.
Topics: Animals; Swine; Intestines; Dietary Supplements; Limosilactobacillus reuteri; Weaning; Cytochromes c; Diet; Diarrhea; Animal Feed
PubMed: 36912248
DOI: 10.1039/d2fo03695a -
PLoS Pathogens Jul 2018We investigated genomic diversity of a yeast species that is both an opportunistic pathogen and an important industrial yeast. Under the name Candida krusei, it is...
We investigated genomic diversity of a yeast species that is both an opportunistic pathogen and an important industrial yeast. Under the name Candida krusei, it is responsible for about 2% of yeast infections caused by Candida species in humans. Bloodstream infections with C. krusei are problematic because most isolates are fluconazole-resistant. Under the names Pichia kudriavzevii, Issatchenkia orientalis and Candida glycerinogenes, the same yeast, including genetically modified strains, is used for industrial-scale production of glycerol and succinate. It is also used to make some fermented foods. Here, we sequenced the type strains of C. krusei (CBS573T) and P. kudriavzevii (CBS5147T), as well as 30 other clinical and environmental isolates. Our results show conclusively that they are the same species, with collinear genomes 99.6% identical in DNA sequence. Phylogenetic analysis of SNPs does not segregate clinical and environmental isolates into separate clades, suggesting that C. krusei infections are frequently acquired from the environment. Reduced resistance of strains to fluconazole correlates with the presence of one gene instead of two at the ABC11-ABC1 tandem locus. Most isolates are diploid, but one-quarter are triploid. Loss of heterozygosity is common, including at the mating-type locus. Our PacBio/Illumina assembly of the 10.8 Mb CBS573T genome is resolved into 5 complete chromosomes, and was annotated using RNAseq support. Each of the 5 centromeres is a 35 kb gene desert containing a large inverted repeat. This species is a member of the genus Pichia and family Pichiaceae (the methylotrophic yeasts clade), and so is only distantly related to other pathogenic Candida species.
Topics: Candida; Metagenomics; Phylogeny; Pichia
PubMed: 30024981
DOI: 10.1371/journal.ppat.1007138 -
Microbial Pathogenesis Dec 2021Mycotoxins are the secondary metabolites of certain toxigenic fungi which pose severe health stress in humans, animals and poultry. Certain biological agents and...
Mycotoxins are the secondary metabolites of certain toxigenic fungi which pose severe health stress in humans, animals and poultry. Certain biological agents and components are used to adsorb mycotoxins in poultry industry which provide promising results in this regard. Pichia kudriazevii (PK), a novel yeast, has the ability to enhance the immune status of poultry chicks. The present study was designed to investigate the ameliorative potential of PK against aflatoxins associated immunosuppression and oxidative stress in broiler chicks. 180-one day old broiler chicks were equally divided into six groups and given different combinations of aflatoxins (300 and 600 μg/kg) and PK (1 g/kg). Parameters studied were antibody response to sheep red blood cells, lymphoproliferative response to PHA-P; phagocytic response by carbon clearance assay system, total antioxidant capacity and total oxidant status of chicks. Results of this experiment confirmed the immunomodulation and antioxidant capacity of PK against 300 μg/kg aflatoxin level. However such amelioration was partial when PK was used with 600 μg/kg aflatoxins. Moreover, the exact ratio of aflatoxin: PK to cause such amelioration still needs to be investigated.
Topics: Aflatoxins; Animal Feed; Animals; Chickens; Dietary Supplements; Oxidative Stress; Pichia; Poultry Diseases; Sheep
PubMed: 34742894
DOI: 10.1016/j.micpath.2021.105279 -
Journal of Advanced Research Jan 2020Olfactory cues have a large impact on insect behaviour and fitness consequently showing potential in pest management. Yeast released volatiles are used by insects as...
Olfactory cues have a large impact on insect behaviour and fitness consequently showing potential in pest management. Yeast released volatiles are used by insects as olfactory cues for finding feeding and oviposition sites. The yeast strain SB-16-15 was isolated from spontaneous fermentation of berries and identified as . Thirty-nine volatiles were sampled from the headspace of yeasts by solid phase micro extraction and identified by gas chromatography and mass spectrometry techniques. Ten of those volatiles elicited antennal responses of flies, one of the most serious pest of berries. In the two-choice experiments, flies preferred the mixture composed of nine synthetic compounds analogous to electroanntenographic active volatiles released by the yeasts compare to the solvent control. Female flies were significantly attracted to the mixture at the concentration 0.1 µL mL and showed no preference to the mixture at the concentration 1 µL mL versus control while males reacted positively to the synthetic blend at the concentration 1 µL mL. Herein, for the first time, behaviour modifying effect of berry related yeast volatiles was shown suggesting these semiochemicals have potential in use for monitoring flies.
PubMed: 32071775
DOI: 10.1016/j.jare.2019.08.001 -
Journal of Fungi (Basel, Switzerland) Nov 2022Yeast strains are widely used in ruminant production. However, knowledge about the effects of rumen native yeasts on ruminants is limited. Therefore, this study aimed to...
Isolation and Characterization of Ruminal Yeast Strain with Probiotic Potential and Its Effects on Growth Performance, Nutrients Digestibility, Rumen Fermentation and Microbiota of Hu Sheep.
Yeast strains are widely used in ruminant production. However, knowledge about the effects of rumen native yeasts on ruminants is limited. Therefore, this study aimed to obtain a rumen native yeast isolate and investigate its effects on growth performance, nutrient digestibility, rumen fermentation and microbiota in Hu sheep. Yeasts were isolated by picking up colonies from agar plates, and identified by sequencing the ITS sequences. One isolate belonging to had the highest optical density among these isolates obtained. This isolate was prepared to perform an animal feeding trial. A randomized block design was used for the animal trial. Sixteen Hu sheep were randomly assigned to the control (CON, fed basal diet, = 8) and treatment group (LPK, fed basal diet plus , CFU = 8 × 10 head/d, = 8). Sheep were housed individually and treated for 4 weeks. Compared to CON, LPK increased final body weight, nutrient digestibility and rumen acetate concentration and acetate-to-propionate ratio in sheep. The results of Illumina MiSeq PE 300 sequencing showed that LPK increased the relative abundance of lipolytic bacteria ( spp. and spp.) and probiotic bacteria ( spp. and spp.). For rumen eukaryotes, LPK increased the genera associated with fiber degradation, including protozoan and fungus . Our results discovered that rumen native yeast isolate might promote the digestion of fibers and lipids by modulating specific microbial populations with enhancing acetate-type fermentation.
PubMed: 36547593
DOI: 10.3390/jof8121260 -
PLoS Pathogens May 2023The pathogenic yeast Pichia kudriavzevii, previously known as Candida krusei, is more distantly related to Candida albicans than clinically relevant CTG-clade Candida...
The pathogenic yeast Pichia kudriavzevii, previously known as Candida krusei, is more distantly related to Candida albicans than clinically relevant CTG-clade Candida species. Its cell wall, a dynamic organelle that is the first point of interaction between pathogen and host, is relatively understudied, and its wall proteome remains unidentified to date. Here, we present an integrated study of the cell wall in P. kudriavzevii. Our comparative genomic studies and experimental data indicate that the general structure of the cell wall in P. kudriavzevii is similar to Saccharomyces cerevisiae and C. albicans and is comprised of β-1,3-glucan, β-1,6-glucan, chitin, and mannoproteins. However, some pronounced differences with C. albicans walls were observed, for instance, higher mannan and protein levels and altered protein mannosylation patterns. Further, despite absence of proteins with high sequence similarity to Candida adhesins, protein structure modeling identified eleven proteins related to flocculins/adhesins in S. cerevisiae or C. albicans. To obtain a proteomic comparison of biofilm and planktonic cells, P. kudriavzevii cells were grown to exponential phase and in static 24-h cultures. Interestingly, the 24-h static cultures of P. kudriavzevii yielded formation of floating biofilm (flor) rather than adherence to polystyrene at the bottom. The proteomic analysis of both conditions identified a total of 33 cell wall proteins. In line with a possible role in flor formation, increased abundance of flocculins, in particular Flo110, was observed in the floating biofilm compared to exponential cells. This study is the first to provide a detailed description of the cell wall in P. kudriavzevii including its cell wall proteome, and paves the way for further investigations on the importance of flor formation and flocculins in the pathogenesis of P. kudriavzevii.
Topics: Saccharomyces cerevisiae; Proteome; Proteomics; Candida albicans; Candida; Biofilms; Genomics; Cell Wall
PubMed: 37196016
DOI: 10.1371/journal.ppat.1011158