26S rRNA Sequence Research Articles

Fermented Ginsenosides Alleviate Acute Liver Injury Induced by CCl4 in Mice by Regulating the AKT/mTOR Signaling Pathway.

This study investigated the alleviating effect of fermented ginsenosides obtained through yeast strain fermentation transformation on acute liver injury (ALI) induced by CCl4. Strains were screened for their ability to produce β-glucosidase, the transformation ability of the strain was verified by high-performance liquid chromatography, and the Saccharomyces cerevisiae strain F6 was obtained by 26S rRNA sequencing. After fermentation by F6 strain, it was found that the content of ginsenosides Re, Rb1, and Rb2 was significantly decreased (P < 0.05), and rare ginsenosides were detected, with the content of Rh4 and Rg5 reaching 2.65 mg·g-1 and 2.56 mg·g-1. We also explored the preventive effect of fermented ginsenoside extract (FGE) on ALI. Mice were evenly divided into 9 groups as follows: control group, ALI model group, positive drug bifendate group, and treatment group, which included 3 ginsenoside extract (GE) groups and 3 FGE groups (dosage of 150, 300, and 450 mg·kg-1 b.w.). The results showed that compared with the ALI model group, FGE significantly increased the levels of glutathione peroxidase, hydroperoxidase, and superoxide dismutase and also decreased the malondialdehyde level. The levels of alanine aminotransferase, aspartate aminotransferase, and total bilirubin markers were significantly reduced, and the levels of inflammatory cytokines TNF-α, IL-6, and IL-1β were significantly decreased. Bioinformatics analysis combined with Western blot validation explored the molecular mechanism of the effect of FGE. It was found that FGE could downregulate the expression of the p-AKT/AKT and the p-mTOR/mTOR ratios. These results suggested that FGE played an alleviative role in ALI by promoting autophagy to inhibit the AKT/mTOR signaling pathway.

Production and structural characterization of eco-friendly bioemulsifier SC04 from Saccharomyces cerevisiae strain MYN04 with potential applications

BackgroundBioemulsifiers are natural or microbial-based products with the ability to emulsify hydrophobic compounds in water. These compounds are biodegradable, eco-friendly, and find applications in various industries.ResultsThirteen yeasts were isolated from different sources in Alexandria, Egypt, and evaluated for their potential to produce intracellular bioemulsifiers. One yeast, isolated from a local market in Egypt, showed the highest emulsification index (EI24) value. Through 26S rRNA sequencing, this yeast was identified as Saccharomyces cerevisiae strain MYN04. The growth kinetics of the isolate were studied, and after 36 h of incubation, the highest yield of cell dry weight (CDW) was obtained at 3.17 g/L, with an EI24 of 55.6%. Experimental designs were used to investigate the effects of culture parameters on maximizing bioemulsifier SC04 production and CDW. The study achieved a maximum EI24 of 79.0 ± 2.0%. Furthermore, the crude bioemulsifier was precipitated with 50% ethanol and purified using Sephadex G-75 gel filtration chromatography. Bioemulsifier SC04 was found to consist of 27.1% carbohydrates and 72.9% proteins. Structural determination of purified bioemulsifier SC04 was carried out using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), high-performance liquid chromatography (HPLC), and nuclear magnetic resonance spectroscopy (NMR). FTIR spectroscopy revealed characteristic bands associated with carboxyl and hydroxyl groups of carbohydrates, as well as amine groups of proteins. HPLC analysis of monosaccharide composition detected the presence of mannose, galactose, and glucose. Physicochemical characterization of the fraction after gel filtration indicated that bioemulsifier SC04 is a high molecular weight protein-oligosaccharide complex. This bioemulsifier demonstrated stability at different pH values, temperatures, and salinities. At a concentration of 0.5 mg/mL, it exhibited 51.8% scavenging of DPPH radicals. Furthermore, in vitro cytotoxicity evaluation using the MTT assay revealed a noncytotoxic effect of SC04 against normal epithelial kidney cell lines.ConclusionsThis study presents a new eco-friendly bioemulsifier, named SC04, which exhibits significant emulsifying ability, antioxidant and anticancer properties, and stabilizing properties. These findings suggest that SC04 is a promising candidate for applications in the food, pharmaceutical, and industrial sectors.

Yeast diversity in Cabernet-Sauvignon and Merlot grapes grown in the highlands of Southern Brazil

Considering the influence of natural yeasts on wine production and the organoleptic properties of the final product, the objective of the present study was to evaluate the diversity of yeasts in Cabernet-Sauvignon and Merlot (Vitis vinifera L.) grown in the highlands of the Northeast region of Rio Grande do Sul State, “Serra Gaúcha”, Brazil. Grape samples were collected from commercial vineyards between February and March in the 2017, 2018 and 2019 vintages. One hundred sixty-six isolated yeasts were classified at the species level by D1/D2 domain of 26S rRNA sequencing. A total of 31 yeast species were identified. The most prevalent species were Hanseniaspora uvarum, Issatchenkia terricola, Saturnispora diversa and Starmerella bacillaris. These same yeasts were the most frequent regardless of the year evaluated. The results indicated that there is a great diversity of yeast species in grapes cultivated in the highlands of Southern Brazil. However, the yeast communities remain similar in Cabernet-Sauvignon and Merlot grapes the analysed parameters (grape variety/vintage) are not interfering in the yeast populations found in the region highlands of Rio Grande do Sul, “Serra Gaúcha”, Brazil. This study enabled the knowledge of the yeast populations present in the region and their variations during the harvesting of wine grapes, showing that there is a majority pattern of species independent of the harvest.

Phenotypic and genotypic characterisation of Lactobacillus and yeast isolates from a traditional New Zealand Māori potato starter culture

Parāroa Rēwena is a traditional Māori sourdough produced by fermentation using a potato starter culture. The microbial composition of the starter culture is not well characterised, despite the long history of this product. The morphological, physiological, biochemical and genetic tests were conducted to characterise 26 lactic acid bacteria (LAB) and 15 yeast isolates from a Parāroa Rēwena potato starter culture. The results of sugar fermentation tests, API 50 CHL tests, and API ID 32 C tests suggest the presence of four different LAB phenotypes and five different yeast phenotypes. 16S rRNA and 26S rRNA sequencing identified the LAB as Lacticaseibacillus paracasei and the yeast isolates as Saccharomyces cerevisiae, respectively. Multilocus sequence typing (MLST) of the L. paracasei isolates indicated that they had identical genotypes at the MLST loci, to L. paracasei subsp. paracasei IBB 3423 or L. paracasei subsp. paracasei F19. This study provides new insights into the microbial composition of the traditional sourdough Parāroa Rēwena starter culture.

First Case of Identification of Candida kefyr and Pichia kluyveri in Lebanese Water

Candida kefyr (Kluyveromyces marxianus) is a clinically important infectious yeast. It is found in nature, and is known to cause diseases in humans. No previous studies known have shown the detection of Candida kefyr in water sources of any country, and no studies have detected it anywhere in Lebanon. This present study is carried out to assess the quality of Lebanese water in terms of yeast pollution. The occurrence of Candida spp. (species) was inspected in 84 water samples that tested positive for containing Candida. Out of all isolates, 12 isolates were of C. kefyr and two were of P. kluyveri. The identification of Candida sp. was carried out by using HiCrome™ M1297A and M1297AR chromogenic media. Isolates identified were confirmed by MALDI-TOF MS and 26S rRNA sequencing. The isolates varied from sensitive to resistant to common antifungal agents, including Itraconazole, clotrimazole, fluconazole, miconazole, and nystatin, via disk diffusion assay. These results are the first to confirm the presence of C. kefyr in Lebanese water supplies and suggest that water consumed in Lebanon may be a potential transmission route for serious Candida-based infections.

Characterization and comparison of yeasts from different sources for some probiotic properties and exopolysaccharide production

Abstract A total of 134 strains of yeasts isolated from fruits and vegetables (certain berry fruits, apples, pomegranates, carrots and grapes), free-range chicken feces and dairy products, and from 10 commercial yeast preparations were identified and subjected to analyses to determine their in vitro probiotic properties. Based on 26S rRNA sequence analysis all ten isolates from commercial products were identified as Saccharomyces cerevisiae, and the natural isolates as Candida corpophila, Candida diddensiae, Clavispora lusitaniae, Hanseniaspora opuntiae, Hanseniaspora uvarum, Kazachstania bovina, Kluyveromyces marxianus, Metschnikowia. pulcherrima, Metschnikowia sp., Meyerozyma carribbica, Pichia kluyveri and Wickerhamomyces anomalus. All isolates were found to be resistant to simulated gastric juice at pH 2.5 for 2 h and were able to grow at both 30 and 37 °C. The exopolysaccharide (EPS) production of isolates from commercial preparations and from natural sources varied between 249-275.22 and 27.95-272.22 mg/L, respectively. Two of the natural isolates had levels of EPS production comparable to the natural strains (S. cerevisiae T8-3C and S. cerevisiae P25-1) with 264.63 and 272.53 mg/L, respectively. Isolates were also investigated for autoaggregation and coaggregation abilities. The highest coaggregation ability was determined for the Saccharomyces cerevisiae P25-1 strain against Staphylococcus aureus (ATCC 25923).

쑥 당-추출액의 발효 중 효모 다양성과 향기성분 변화

In this study, we investigated the changes in physicochemical properties, yeast diversity, and volatile flavor compounds during fermentation of mugwort sugar extracts (FMSE). The pH and sucrose levels decreased, while the acidity and reducing sugar, fructose, and glucose contents increased during FMSE. Oxalic and succinic acids appeared to be the predominant organic acids in FMSE. Based on 26S rRNA sequencing, a total of 7 different yeast species including Candida lactis-condensi, Hanseniaspora uvarum, Hyphopichia burtonii, Saccharomyces cerevisiae, Saccharomyces paradoxus, Torulaspora delbruechii, and Zygosaccharomyces pseudorouxii were identified in 5 sampling sites. The prevalence of S. cerevisiae was highest (95%) at 30 days and decreased to 7.5% at 60 days, whereas the abundance of C. lactis-condensi increased from 90% at 60 days to 100% at 90 days of fermentation. The major volatile flavor compound, 3-methyl-1-butanol, considerably increased from 65.95% to 82.98% after 30 days of fermentation and slightly decreased thereafter. In addition, the levels of benzyl alcohol, phenylethyl alcohol, and 5-hydroxymethyl-2-furancarboxyaldehyde increased to 2.56%, 5.48%, and 2.54%, respectively, whereas isopentyl alcohol substantially decreased to 0.12%, at 120 days of fermentation.

Development of high biomass and lipid yielding medium for newly isolated Rhodotorula mucilaginosa

Conversion of plant-based biomass into biofuels has been singled out as a way to achieve economically viable production chains. Over past few decades development in yeast oil production have been witnessed, which includes isolation of high lipid accumulating strains, understanding the metabolic pathways for oil production, genetic engineering strategies for overproduction of lipids and optimization of cultivation processes for converting lignocellulose biomass to oil. In the present investigation, screening, isolation and characterization of novel oleaginous yeast from oil refinery was carried out. The strain was identified as Rhodotorula mucilaginosa by 26s rRNA sequencing (Accession Number: KX533469). Glucose and peptone were identified as best carbon and nitrogen source for high biomass induction. Further, two-stage optimization using taguchi orthogonal array method and multi objective optimization using genetic algorithm was applied for the development of an optimized medium. Malt extract was found to be a key influencing factor in both biomass and lipid induction with high S/N ratio, followed by peptone and glucose. Batch bioreactor studies revealed that the lipid productivity follows mixed growth associated pattern with the higher lipid accumulation of 0.25 g/g biomass.

Identification of Zygosaccharomyces mellis strains in stored honey and their stress tolerance.

To screen yeast with high sugar tolerance and evaluate their stress tolerance, six yeast strains were selected from 17 stored honey samples. The species were identified through 26S rRNA sequencing. Their stress tolerance was determined via the Durham fermentation method and ethanol production ability was determined via flask fermentation. The results demonstrated that all the six strains were Zygosaccharomyces mellis. Their sugar, ethanol, and acid tolerance ranges were 500-700 g/L, 10-12% (v/v), and pH 2.5-4.5, respectively. The SO2 tolerance was 250 mg/L. Among the six strains, 6-7431 had the best stress tolerance with sugar tolerance of 700 g/L, ethanol tolerance of 12% (v/v), and acid tolerance of pH 2.5. Furthermore, the strain of 6-7431 had the highest percentage of ethanol production at the same initial sugar content as the other strains. Therefore, the selected six yeast strains would be promising fermentation yeasts for wine-making, ethanol production, or other fermentation purposes.

Culture-independent analysis of yeast diversity in Korean traditional fermented soybean foods (doenjang and kanjang) based on 26S rRNA sequence

The yeast-26S rRNA libraries were constructed from two different fermented soybean foods, doenjang and kanjang. A total of 42 clones, containing the partial 26S rRNA sequences, 0.6 kb in length, were sequenced and subjected to an online similarity search. All doenjang yeast (DY) clones only appeared in the Saccharomycotina class. The 21 clones from the doenjang library were classified into five groups: Debaryomyces hansenii (DY I, 76.0 %), Zygosaccharomyces pseudorouxii (DY II, 9.6 %), Candida versatilis (DY III, 4.8 %), Candida etchellsii (DY IV, 4.8 %), and Debaryomyces castellii (DY V, 4.8 %). The 21 kanjang yeast (KY) clones were affiliated with the Saccharomycotina (52.4 %), Urediniomycetes (19.0 %), Ustilaginomycetes (23.8 %), and Hymenomycetes (4.8 %) classes and divided into six groups: D. hansenii (KY I, 38.0 %), Sterigmatomyces halophilus (KY II, 19.0 %), Malassezia restricta (KY III, 23.8 %), Cryptococcus magnus (KY V, 4.8 %), and Pichia triangularis (KY VI, 9.6 %). Yeast belonging to the Saccharomycotina class was predominant (76.2 %) in fermented soybean foods, doenjang and kanjang. These findings are of fundamental value for understanding the complexity of two different fermented soybean foods.

Molecular characterization and lipase profiling of the yeasts isolated from environments contaminated with petroleum

In the present study, 120 yeast isolates from different sources (active sludge, soil, and wastewater samples obtained from petroleum refinery and soil contaminated by petroleum) were obtained. The yeast isolates were screened for lipase production and twelve of the isolates (D3, D17, D24, D27, D30, D38, D40, D42, D44, D46, D56, and D57) exhibited lipase activity. Molecular characterization of the yeasts showing the lipase production was performed with RFLP of ITS1-5.8S-ITS2 and 18S rRNA and sequence analysis of D1/D2 domain of 26S rRNA. The 26S rRNA sequencing revealed that four new strains, D38, D40, D44 and D57 identified as Rhodotorula slooffiae, Candida davisiana, Cryptococcus diffluens, and Cryptococcus uzbekistanensis, respectively, are lipase producing yeast species. This study is the first report showed lipase production by these species. The other lipase producing strains identified as Candida parapsilosis (D3), Rhodotorula muciloginosa (D17 and D42), Cryptococcus albidus (D24, D27, D30, and D56), and Wickerhamomyces anomalus (D46).

A wild and tolerant yeast suitable for ethanol fermentation from lignocellulose

Ethanol fermentation from food wastes containing mainly starch without carrying out sterilization was investigated by using wild and tolerant yeast, Issatchenkia orientalis MF-121. The MF-121 strain is not a suitable choice for ethanol fermentation from lignocellulosic biomass because it is only capable of fermenting hexoses of glucose, mannose, and fructose to ethanol. Therefore, we first isolated acid- and salt-tolerant yeast that are capable of fermenting various monosaccharides to ethanol, and the isolated yeast that showed the ability to ferment ethanol from glucose, mannose, galactose, fructose, and xylose, was identified as Zygoascus hellenicus LK-5G on the basis of the 26S rRNA sequence analysis.

Ethanol yield and volatile compound content in fermentation of agave must by Kluyveromyces marxianus UMPe-1 comparing with Saccharomyces cerevisiae baker's yeast used in tequila production

In tequila production, fermentation is an important step. Fermentation determines the ethanol productivity and organoleptic properties of the beverage. In this study, a yeast isolated from native residual agave must was identified as Kluyveromyces marxianus UMPe-1 by 26S rRNA sequencing. This yeast was compared with the baker's yeast Saccharomyces cerevisiae Pan1. Our findings demonstrate that the UMPe-1 yeast was able to support the sugar content of agave must and glucose up to 22% (w/v) and tolerated 10% (v/v) ethanol concentration in the medium with 50% cells survival. Pilot and industrial fermentation of agave must tests showed that the K. marxianus UMPe-1 yeast produced ethanol with yields of 94% and 96% with respect to fermentable sugar content (glucose and fructose, constituting 98%). The S. cerevisiae Pan1 baker's yeast, however, which is commonly used in some tequila factories, showed 76% and 70% yield. At the industrial level, UMPe-1 yeast shows a maximum velocity of fermentable sugar consumption of 2.27g·L(-1)·h(-1) and ethanol production of 1.38g·L(-1)·h(-1), providing 58.78g ethanol·L(-1) at 72h fermentation, which corresponds to 96% yield. In addition, the major and minor volatile compounds in the tequila beverage obtained from UMPe-1 yeast were increased. Importantly, 29 volatile compounds were identified, while the beverage obtained from Pan1-yeast contained fewer compounds and in lower concentrations. The results suggest that the K. marxianus UMPe-1 is a suitable yeast for agave must fermentation, showing high ethanol productivity and increased volatile compound content comparing with a S. cerevisiae baker's yeast used in tequila production.

Sequence and variability of the 5.8S and 26S rRNA genes of Pneumocystis carinii.

The sequence of the coding region of the rRNA operon of rat-derived Pneumocystis carinii has been completed, including the genes for 5.8S and 26S rRNA. These genes show homology to the rRNA genes of yeast, and an apparent group I self-splicing intron is present in the 26S rRNA gene. Like a similar intron in the 16S rRNA gene, this intron is in a phylogenetically conserved region. Variation in the 26S rRNA sequence was noted between P. carinii organisms isolated from two different sources.

Phylogeny of the colonial green flagellates: a study of 18S and 26S rRNA sequence data

A study of phylogenetic relationships of the colonial green algal flagellates based on nuclear 18S and 26S rRNA sequence data suggests that the colonial habit has had at least two independent origins. All colonial taxa included in the analysis, except Stephanosphaera, are allied in a clade with Chlamydomonas reinhardtii and other Chlamydomonas taxa ascribed to the Euchlamydomonas group by Ettl. In contrast, Stephanosphaera is allied with other unicellular flagellates including Haematococcus. Comparison of the 18S and 26S data shows that the two sets of data yield different results following cladistic analysis. The 18S data provide the principal signal that supports the more basal divergences, but the data do not unambiguously address relationships among taxa in the clade that includes most colonial flagellates and Chlamydomonas taxa representative of the Euchlamydomonas group (sensu Ettl). In contrast, the 26S data have fewer informative sites that support basal divergences than the 18S data, but provide much of the signal that supports resolution of taxa in the colonial flagellate clade in an analysis of the combined 18S and 26S rRNA sequence data. Additional sequence data from the 26S molecule and additional taxa may reduce the topological ambiguity inferred from the sequence data for the colonial flagellates. Alternatively, an ancient and rapid radiation of taxa in the colonial lineage could account for the topological ambiguity. Despite some unresolved questions of relationships, cladistic analysis of the combined data sets provides some robustly supported concepts of evolution in these flagellates.

The primary transcript of the ribosomal repeating unit in yeast.

Endgroup analysis of 37S ribosomal precursor RNA from Saccharomyces carlsbergensis has revealed that the major 5' endgroup is ppA-Up, with a molar yield of 0.8. This shows that most, if not all, 37S RNA molecules have preserved a transcriptional initiation sequence. Analysis of the 3' terminus of 37S RNA has shown the presence of a uridine rich oligonucleotide, tentatively identified as U6-8-A-NOH. This long stretch of uridines at the 3' end of 37S RNA may represent a transcriptional termination site. The two sets of data on the terminal sequences suggest that 37S ribosomal precursor RNA, if not already spliced, is a primary transcription product. Since the 3' terminus of 26S rRNA, U-U-U-G-UOH., appears to be clearly different from the 3' end of 37S RNA, we conclude that 37S ribosomal precursor RNA contains additional nucleotides 3'-distal to the 26S rRNA sequence.