In Vitro Studies on Therapeutic Potential of Probiotic Yeasts Isolated from Various Sources.

The present study investigates the therapeutic properties of probiotic yeasts viz. Yarrowia lipolytica VIT-MN01, Kluyveromyces lactis VIT-MN02, Lipomyces starkeyi VIT-MN03, Saccharomycopsis fibuligera VIT-MN04 and Brettanomyces custersianus VIT-MN05. The antimutagenic activity of probiotic yeasts against the mutagens viz. Benzo[a]pyrene (B[a]P), and Sodium azide (SA) was tested. S. fibuligera VIT-MN04 showed highest antimutagenicity (75%). Binding ability on the mutagen acridine orange (AO) was tested and L. starkeyi VIT-MN03 was able to bind AO effectively (88%). The probiotic yeasts were treated with the genotoxins viz. 4-Nitroquinoline 1-Oxide (NQO) and Methylnitronitrosoguanidine (MNNG). The prominent changes in UV shift confirmed the reduction in genotoxic activity of S. fibuligera VIT-MN04 and L. starkeyi VIT-MN03, respectively. Significant viability of probiotic yeasts was noted after being exposed to mutagens and genotoxins. The adhesion capacity and anticancer activity were also assessed using Caco-2 and IEC-6 cell lines. Adhesion ability was found to be more in IEC-6 cells and remarkable antiproliferative activity was noted in Caco-2 cells compared to normal cells. Further, antagonistic activity of probiotic yeasts was investigated against S. typhimurium which was found to be more in S. fibuligera VIT-MN04 and L. starkeyi VIT-MN03. The inhibition of α-glucosidase and α-amylase activity confirmed the antidiabetic activity of probiotic yeasts. Antioxidant activity was also tested using standard assays. Therefore, based on the results, it can be concluded that probiotic yeasts can serve as potential therapeutic agents for the prevention and treatment of colon cancer, type 2 diabetes and gastrointestinal infections.

The mycoparasitic yeast Saccharomycopsis schoenii predates and kills multi-drug resistant Candida auris.

Candida auris has recently emerged as a multi-drug resistant fungal pathogen that poses a serious global health threat, especially for patients in hospital intensive care units (ICUs). C. auris can colonize human skin and can spread by physical contact or contaminated surfaces and equipment. Here, we show that the mycoparasitic yeast Saccharomycopsis schoenii efficiently kills both sensitive and multi-drug resistant isolates of C. auris belonging to the same clade, as well as clinical isolates of other pathogenic species of the Candida genus suggesting novel approaches for biocontrol.

Effect of bioaugmented inoculation on microbiota dynamics during solid-state fermentation of Daqu starter using autochthonous of Bacillus, Pediococcus, Wickerhamomyces and Saccharomycopsis.

Daqu, a traditional fermentation starter that is used for Chinese liquor and vinegar production, is still manufactured through a traditional spontaneous solid-state fermentation process with no selected microorganisms are intentionally inoculated. The aim of this work was to analyze the microbiota dynamics during the solid-state fermentation process of Daqu using a traditional and bioaugmented inoculation with autochthonous of Bacillus, Pediococcus, Saccharomycopsis and Wickerhamomyces at an industrial scale. Highly similar dynamics of physicochemical parameters, enzymatic activities and microbial communities were observed during the traditional and bioaugmented solid-state fermentation processes. Both in the two cases, groups of Streptophyta, Rickettsiales and Xanthomonadales only dominated the first two days, but Bacillales and Eurotiales became predominant members after 2 and 10 days fermentation, respectively. Phylotypes of Enterobacteriales, Lactobacillales, Saccharomycetales and Mucorales dominated the whole fermentation process. No significant difference (P > 0.05) in microbial structure was observed between the traditional and bioaugmented fermentation processes. However, slightly higher microbial richness was found during the bioaugmented fermentation process after 10 days fermentation. Our results reinforced the microbiota dynamic stability during the solid-state fermentation process of Daqu, and might aid in controlling the traditional Daqu manufacturing process.

Identification of three yeast species using the conventional and internal transcribed spacer region sequencing methods as first or second global record from human superficial infections.

During the mycological analysis of skin and nail samples taken from patients with onychomycosis and tineas in Assiut city, it is interesting to report that yeast fungi were the main causal agents being cultured from 45.79% of total cases. In general, 21 species of yeast were isolated. Some of these are reported for the first time from clinical specimens. From the literature available up-to-date around the world, this study reports for the first time Saccharomycopsis fibuligera as the causal agent of four clinical cases: two onychomycoses, one tinea capitis and one tinea amiantacea. Also, it is reported here the second record for Trichosporon dohaense from a case of onychomycosis of a 40-year-old woman (after its original description in 2009 by Taj-Aldeen et al. J Clin Microbiol 47: 1791). Candida galli was also reported for the first time from clinical specimen (tinea unguium) in 2014 by Galán-Sánchez et al. Mycopathol 178: 303, and this study reports the second case of onychomycosis by C. galli. These strains were identified on the basis of their phenotypic, biochemical, physiological and genotypic features. Strains and internal transcribed spacer (ITS) gene sequences of these species are deposited at Assiut University Mycological Center Culture Collection (AUMC) and National Center for Biotechnological Information (NCBI) respectively.

The presence of 3-hydroxy oxylipins on the ascospore surfaces of some species representing Saccharomycopsis Schiönning.

Through gas chromatography - mass spectrometry, the presence of oxylipins, mainly 3-hydroxy 9:1 and 3-hydroxy 10:1, was detected in Saccharomycopsis fermentans, Saccharomycopsis javanensis, and Saccharomycopsis vini. The distribution of these compounds was mapped using immunofluorescence microscopy, and they were found to be closely associated with the surfaces of aggregating ascospores.

[Metabolism of ginsenoside Rb1 and panaxadiol saponins by fungi].

AIM: To study the metabolic process of ginsenoside Rb1 (G-Rb1) and panaxadiol saponins (PDS) by fungi. METHODS: Ten strains of fungi were incubated with G-Rb1 and PDS at a certain temperature with shaking. A portion was taken out at different time and mixed up with butanol. The butanol extract was analysed by thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and electrospray ionazition mass spectrometry (ESI-MS). RESULTS: It was found that there were ginsenoside-Rd (G-Rd), ginsenoside-F2 (G-F2), compound K (CK) and 20(S) protopanaxadiol (Ppd) metabolites beside the prodrug G-Rb1 induced by fungi (No. 1, 2, 3, 6, 8, 9). CONCLUSION: The six strains of fungi have different degrees of ability to metabolize G-Rb1 and PDS. The possible metabolic process could be as follows: G-Rb1 (or PDS)-->G-Rd-->G-F2-->CK-->Ppd.

Cyniclomyces guttulatus (Saccharomycopsis guttulata)--culture, ultrastructure and physiology.

Organisms that form an essential extra inner lining of selected areas of the stomach mucosa occur in mice, rats and some other animals. The yeast Cyniclomyces guttulatus (Saccharomycopsis guttulata) was shown in this study to line the stomach of domestic and feral rabbits, guinea pigs, and chinchillas. The layer of yeast cells formed a loose barrier between lumen contents and mucosal surface. A rapid rate of multiplication in the stomach provided yeast cells that blended in with stomach lumen contents, passed through the gut, and were finally excreted in large numbers in fecal pellets. Ascospore formation occurred during passage through the large intestine. The layer of yeast cells lining the stomach had no evident salubrious nor deleterious effect on the animal. C. guttulatus grew rapidly from stomach contents or single fecal pellets in a new enriched semisolid medium. Growth was good at pH 1 through 8 on the solidified enriched medium. A very unusual characteristic of C. guttulatus is optimal growth at 38 degrees C, and growth at 42 degrees C, with failure to grow below 30 degrees C. TEM demonstrated a very thick, laminated cell wall which had a thick, filamentous external coating. There were mitochondria, polyribosomes, lipid droplets, and an unusually large central nucleus. The developing spore nucleus became extremely electron dense and encapsulated, along with condensed mitochondria, ribosomes, short membrane sections and other organelles, in a dense lamellar covering.

Dielectrophoretic properties of yeast cells dividing by budding and by transversal fission.

The dielectrophoretic behaviour of yeast cells dividing by budding or by transversal fission was analyzed. The results obtained show that the dielectrophoretic yield is a linear function of alternating voltage, cell concentration and the square root of the time of collection in all the species assayed. Dependence of the rate of collection on the frequency of the voltage applied (between 0.2 and 5 MHz) was also found. This behaviour is similar in the three microorganisms studied. The scale factor correlating the frequency spectrum for Saccharomyces cerevisiae and Saccharomycopsis lipolytica is proportional to cell size. However, these results can not be extended to Schizosaccharomyces pombe. A relationship between the dielectrophoretic yield and the age of the culture and the consumption of glucose has been established for the three yeast strains. Dielectrophoresis also permits the differentiation between viable and non-viable cells.

Use of nystatin for random spore selection in the yeast Saccharomycopsis lipolytica.

Nystatin was used to develop a new method to select spores of the yeast Saccharomycopsis lipolytica. At low concentrations nystatin killed preferently growing cells of this yeast. At high concentrations nongrowing cells were affected as well. In contrast, spores were not sensitive to nystatin action. This differential response to the antibiotic suggested its use to select spores from sporulated yeast cultures.

Development of breeding stocks of the yeast Saccharomycopsis lipolytica by methods of moderate inbreeding.

Sporulation parameters of genetically labelled strains, derived from a wild strain of the alkane-utilizing yeast Saccharomycopsis lipolytica were improved by a breeding program using brother-sister crosses. Sporulation frequency, the number of four-spored asci and viability of ascospores could be significantly enhanced. To date a number of genetically well-defined strains is available that have good sporulation parameters and show a 1:1 segregation pattern of markers suitable for genetic analysis.

Conjugation in the yeast Saccharomycopsis capsularis Schiönning.

Cells of the yeast Saccharomycopsis capsularis fused in pairs after disolving of part of the cross wall between them near the lateral wall. After nuclear migrations through the opening, the cross wall was closed again and the cells at both sides became asci. The wall of the ascospores developed from a prospore wall. Between the two unit membranes a very thin dark layer broadened to the dark layer of the wall and after that, the light inner layer developed. Immature spores in the strain studied had a ledge which disappeared during maturation.