Effect of β-Glucan (Angel Yeast) Compared to a Placebo on Cold and Flu Incidence and Symptoms in an Adult Population—A Double Blind, Randomised Controlled Trial

Background: 1-3, 1-6 β-glucan derived from Baker’s yeast (Saccharomyces cerevisiae) has been widely studied for its immune stimulatory capabilities and safety. Previous studies found β-glucan to have efficacy at reducing incidence of URTIs as well as being a low risk for negative side effects. The current study aimed to examine the effects of yeast β-glucan (Angel Yeast) on cold and flu incidences and symptoms in healthy adults. Methods: Two hundred and thirty-one males and females aged 18 to 65 years old supplemented with either β-glucan or a placebo for 3-months. Participants completed a general health questionnaire every 4 weeks and in addition, if participants experienced any cold or flu symptoms, these were recorded daily (along with severity) until resolved or up to 2 weeks. Results: Supplementation with β-glucan reduced the self-reported severity of sore throats and improved sleep quality compared to the placebo group. Conclusions: Yeast β-glucan supplementation appears to be able to help reduce certain symptoms experienced during a cold or flu episode and is safe and well tolerated.

Mathematical Modeling of Cell Polarity Establishment of Budding Yeast

The budding yeast Saccharomyces cerevisiae is a powerful model system for studying the cell polarity establishment.The cell polarization process is regulated by signaling molecules,which are initially distributed in the cytoplasm and then recruited to a proper location on the cell membrane in response to spatial cues or spontaneously.Polarization of these signaling molecules involves complex regulation,so the mathematical models become a useful tool to investigate the mechanism behind the process.In this review,we discuss how mathematical modeling has shed light on different regulations in the cell polarization.We also propose future applications for the mathematical modeling of cell polarization and morphogenesis.

Influence of nitrogen status on fermentation performances of non-Saccharomyces yeasts:a review

Nitrogen,one of the most crucial nutrients present in grapes and musts,plays a key role in yeast activities during alcoholic fermentation.Such influences are imposed on yeast growth and fermentation performances including the formation of secondary metabolites.Saccharomyces cerevisiae,the main yeast responsible for fermentation,has been studied extensively regarding nitrogen impacts.On the other hand,a similar study for non-Saccharomyces yeasts,whose contributions to winemaking have gradually been acknowledged,remains to be fully explored,with a few studies being reported.This review starts by discussing nitrogen impacts on non-Saccharomyces yeast growth and fermentation kinetics in different case scenarios,then proceeds to summarize the nitrogen preferences of individual yeast strains with regulation mechanisms elucidated by recent studies.Detailed discussions on the influences on the production of volatile compounds and proposed pathways therein are made,followed by future work suggested as the final section.In summarizing the nitrogen impacts on non-Saccharomyces yeasts throughout alcoholic fermentation,this review will be helpful in obtaining a more comprehensive view on these non-conventional wine yeasts in terms of nutrient requirements and corresponding volatile production.Research gaps will therefore be elucidated for future research.

Impact of Storage Temperature on Microbial Diversity and Probiotic Effect of Liquid Brewers’ Yeast

Using probiotics as animal feed additives instead of antibiotics is gaining momentum to avert adverse negative effects on human health. Liquid brewers yeast (LBY) is an industrial by-product containing probiotic microorganisms and is also used as a protein supplement for dairy animals. Nevertheless, value chain actors lack of appropriate handling practices compromises the by-products quality and safety. This study aimed to determine the effect of variation in temperature on microbial diversity and probiotic effects during the storage time of LBY sampled from distributors and farmers from Githunguri sub-county of Kenya. The samples were stored at 20C, 25C and 30C, then tested on 0, 5, 10, 15 and 20 days. The studys parameters involved determining the pH levels, lactic acid bacteria (LAB), total coliform count (TCC), mould, and yeast in LBY. The rate (k) of the reaction kinetics model was used to extrapolate the expected probiotic shelf life. The LAB and yeast populations were reduced in a first-order reaction at all storage temperatures. The rate of reduction in the numbers of LAB reduced with an increase in temperature (k = 0.019 and 0.023) at 20C and 30C, respectively. Yeasts highest rate of growth reduction was 25C (k = 0.009) and least at 30C (k = 0.043). The minimum effective concentration for probiotics of 106 CFU/mL needed to observe the beneficial physiological impact on farm animals was achieved between 34.9 and 35.5 days at the tested storage temperatures. The study provides insight into the unexploited low-cost probiotic potential of LBY in dairy production. Conversely, handling practices and environmental microbial contamination along the value chain can compromise product quality and safety. There is a need to advocate its use in dairy for improved productivity and sensitize farmers to appropriate hygienic measures along the LBY value chain.

Improving Semi-Dried Brown Rice Noodle Quality via Mixed Fermentation of Lactobacillus and Yeast

To address the coarse texture and poor cooking quality of brown rice flour,we employed fermentation using lactobacillus and yeast in varying proportions.The fermented flour from early indica rice Pear 13 was then processed into semi-dried brown rice noodles.

Microbiological Quality of “Rabilé”, a Yeast Used for Fermentation of Dolo, a Local Beer in Dédougou, Burkina Faso

Sorghum beer or dolo is part of the eating habits of part of the population of Dédougou because of its low price compared with industrial beers. Its production is an ancestral tradition that uses traditional equipment and gives dolo organoleptic properties that are not found in industrial beers. The production process involves several stages, including fermentation, which itself comprises natural lactic fermentation followed by alcoholic fermentation using traditional yeasts, which are not controlled in any way. The general aim of this study is to assess the microbiological quality of these fermentative yeasts in the town of Dédougou, in order to contribute to the health safety of the population and the promotion of these local beers. Twenty samples of fermenting yeast were analyzed according to ISO standards, to isolate enterobacteria, total and faecal coliforms according to standard procedures for isolating these micro-organisms. The isolated strains were identified using the API20E gallery. Microbiological analyses revealed the presence of 51.17% enterobacteria, 45.38% total coliforms and 3.45% thermotolerant coliforms. We counted 40% Escherichia coli, 20% Enterobacter cloacae, 20% Klebsiella pneumoniae and 20% Klebsiella spp. All the strains detected are capable of surviving in hostile conditions and could harm the quality of the dolo, consumer health and cause real collective food poisoning in the town of Dédougou. This enabled us to assess the microbial quality of these yeasts and to propose more suitable measures for producing and preserving dolo under hygienic conditions to protect consumer health.

Immobilization techniques for beverage production using yeast cell systems: challenges, types, and future perspectives - a mini review

Yeast immobilization is a process of physical entrapment of yeast cells using different techniques while maintaining their biological activity.Continuous fermentation systems have significant advantages over conventional methods.Research highlights that immobilized yeast cell systems have several benefits as compared to free yeast cells.The immobilized yeast cell systems improve fermentation rates,especially when paired with continuous fermentation and appropriate immobilization techniques.Understanding various immobilization techniques,continuous fermentation processes,yeast metabolic activity related to beverage flavor production,and bioreactor designs is vital for optimizing the use of immobilized yeast cells systems on industrial scale.This review provides an overview of recent basic research on immobilized yeast cell systems,with a focus on continuous beverage fermentation.In this study,different reactor configurations and immobilization techniques are explored.The study focus on the impacts of immobilization on the yeast cells,and discuss the recent advancements in these techniques.The review concludes with a discussion on the practical applications of immobilized yeast cells and continuous fermentation in beverage production.

Dairy Farming Conditions and Utilization Levels of Liquid Brewers’ Yeast in Kenya

Dairy production plays an integral part in supporting smallholder farmers’ livelihoods. The desire to increase the number of dairy cattle is not feasible due to the reduced output of feed resources occasioned by climate change. Consequently, the need to increase productivity per cow is inevitable. Conventional protein supplements are costly;hence, the need to explore affordable nutrientdense alternative feed resources. Liquid brewers’ yeast (LBY), a by-product of the brewing industry, is a rich protein supplement in dairy production. This study aimed to assess the dairy farming conditions and utilization levels of LBY as a feed supplement in Githunguri Sub-county, Kiambu. Semi-structured questionnaires were administered to 457 dairy farmers in a cross-sectional survey. The findings revealed that most farmers (94.2%) fed their cattle on established forage/fodder and crop residues with supplementation. Even though 53.1% of the respondents were aware of the use of LBY, only 30.6% utilized it to supplement dairy cows, most of whom (96.0%) used it fresh without preservation. Membership in farmers’ organizations increased awareness of LBY (r = 0.732). Principal component analysis indicated that the benefits of using LBY outweigh the challenges involved with a loading matrix of 0.891 - 0.954 and 0.681 - 0.807, respectively. The low adoption and use levels of LBY as a source of protein supplements were due to low awareness. There is a need for concerted efforts by stakeholders in the industry to increase farmers’ knowledge base on the utilization and effectiveness of LBY in dairy production.

ARTP-ALE Optimized Selection of Low Acetaldehyde Producing Brewer's Yeast and Fermentation Validation

Higher levels of acetaldehyde in beer are one of the major concerns in the current beer industry.Yeast produces acetaldehyde during alcoholic fermentation,and its modification significantly affects beer flavor and quality.A different mutant strain with lower acetaldehyde production and improved ethanol tolerance was constructed using the ARTP-ALE mutagenesis strategy with 4-methylpyrazole-disulfiram.As a result of the mutation,the alcohol dehydrogenase activity of the mutant strain decreased to about 71.22%of that of the wild-type strain.At the same time,the fermentation properties and genetic stability of the newly screened strain showed slight differences from the wild-type strain,and there were no safety concerns regarding industrial use of the mutant strain.

Evaluation and selection of yeasts as potential aroma enhancers for the production of dry-cured ham

Yeasts play a critical role in the flavor formation of dry-cured ham.In this study,41 yeast isolates from the dry-cured ham at different processing stages were evaluated for their technological properties.Debaryomyces hansenii was the most dominant yeast and has been detected at each phase of dry-cured ham,followed by Candida zeylanoides which was mainly detected in salting phase.Yarrowia bubula and Yarrowia alimentaria were found at the first two-phase of dry-cured ham.All isolates of yeast showed enzymatic activities against milk protein and tributyrin,while only 4 strains displayed proteolytic activity on meat protein.Yeast strains were grown in a meat model medium and volatile compounds were identified.The result showed that inoculated yeast strains could promote the production of volatiles and there were significant differences among strains.D.hansenii S25 showed the highest production of volatile compounds,followed by the strain C.zeylanoides C4.D.hansenii S25 was the highest producer of alcohols showing the highest production of benzeneethanol and 3-(methylthio)-1-propanol.Based on OAV and PLS analysis,D.hansenii S25 was strongly correlated with overall flavor and key volatile compounds of dry-cured ham,which could be selected as potential starter cultures.

Growth performance,nutrient digestibility,intestinal morphology,cecal mucosal cytokines and serum antioxidant responses of broiler chickens to dietary enzymatically treated yeast and coccidia challenge

Background There is a growing search for natural feed additives to alleviate the deleterious effects of coccidia infection in poultry production.This study aimed to investigate the effect of enzymatically treated yeast(ETY) on the growth performance,nutrient digestibility,intestinal morphology,antioxidative status,and cecal mucosa cytokines of coccidia-challenged broiler chickens.Methods From d 1 to 14 post hatching,480 broiler chickens were allocated to 3 corn-soybean meal-based experimental diets with increasing concentrations of ETY(0,1,or 2 g/kg).The experiment was designed as a randomized complete block design with body weight(BW) used as a blocking factor.On d 14 post hatching,the birds were re-randomized within each of the 3 experimental diets.Each of the 3 diet groups was split into a challenge or no-challenge group.This resulted in a 3 × 2 factorial arrangement of treatments.The coccidia challenge was administered on d 15 by an oral gavage.Results Dietary ETY improved(P < 0.05) the G:F of birds on d 21 regardless of the challenge state and linearly increased(P < 0.01) the apparent ileal digestibility of dry matter(DM),nitrogen,and gross energy(GE).The coccidia challenge decreased(P < 0.05) BW gain and feed intake of broiler chickens and reduced(P < 0.01) the total tract retention of DM,GE,and nitrogen.The coccidia challenge increased(P < 0.01) the mRNA gene expression of TNFα,IL-1β,IL-10,and IL-6 in the cecal mucosa.There was a tendency(P ne = 0.08) for ETY to linearly reduce IL-1β expression.Additionally,ETY supplementation increased(P < 0.05) the geexpression of OCLN.Serum catalase increased(P < 0.05) with dietary ETY in broiler chickens on d 21.Dietary ETY linearly increased(P < 0.05) the ileal villus height to crypt depth ratio,and ileal goblet cell density in broiler chickens.The ileal and excreta oocyst counts decreased(P < 0.01) with increasing supplementation of dietary ETY in coccidia-challenged broiler chickens on d 21.Conclusions Dietary ETY enhanced nutrient utilization and augmented intestinal development in broiler chickens.However,dietary ETY did not completely attenuate the adverse effects of a coccidia challenge in broiler chickens.

Meta-Analysis Study of the Effects of Yeast Probiotic Supplementation on Milk Production and Energy Corrected Milk of Lactating Dairy Cows

The aim of this study was to use a meta-analytic approach to evaluate the effect of commercially available yeast probiotic “Actisaf®; Sc 47” (Saccharomyces cerevisiae CNCM I-4407) produced and marketed by Phileo by Lesaffre on milk performance in dairy cows. Data from 22 trials including 17 with parallel designs and 5 with cross-over designs were collected, and only data with parallel designs were analyzed. From those trials, 4 are published and 13 are from technical reports. In total, 34 comparisons and 1074 dairy cows met the criteria for inclusion in the final analysis of milk yield (MY). For energy corrected milk (ECM), six trials with 12 comparisons and 476 dairy cows met the criteria for inclusion in the final analysis. Because the data are from different trials with different conditions, the statistical model defined includes the fixed effect of the treatment (with vs. without Actisaf® Sc 47) and the random effect of the trial. The meta-analysis showed a moderate heterogeneity for MY and ECM. The random effect meta-analysis showed an estimated mean difference +1.72 kg/d [95% confidence interval (CI): 1.01 to 2.44] and +2.45 kg/d (95% CI: 1.73 to 3.17) for MY and ECM respectively, in favour of Actisaf® Sc 47. The analysis of data without trials conducted under heat stress conditions showed positive effect of Actisaf® Sc 47. The random effect meta-analysis showed an estimated mean difference of +1.69 kg/d [95% CI: 1.24 to 2.14] and +2.92 kg/d (95% CI: 2.45 to 3.40) for MY and ECM respectively, in favour of Actisaf® Sc 47. These observations provide strong evidence that this commercially available yeast probiotic can significantly improve milk performances of dairy cows under different conditions.

A systematic identification of cold tolerance genes in peanut using yeast functional screening system

Peanut(Arachis hypogaea L.)is a thermophilic crop,and low temperature leads to a significant reduction in annual yields.Despite a few cold tolerant germplasms or cultivars have been discovered and developed,molecular mechanisms governing peanut cold tolerance is poorly understood.Identification of keys genes involved in cold tolerance is the first step to address the underlying mechanism.In this study,we isolated and characterized 157 genes with potentials to confer cold tolerance in peanut by using a yeast functional screening system.GO(Gene ontology)and KEGG(Kyoto encyclopedia of genes and genomes)enrichment analysis of these genes revealed that ribosome and photosynthesis proteins might play essential roles in peanut cold response.Transcriptome results indicated that 60 cold tolerance candidate genes were significantly induced or depressed by low temperature.qRT-PCR analysis demonstrated that several candidate genes could be also regulated by salt or drought stress.Individual overexpression of two UDP-glycosyltransferases(AhUGT2 and AhUGT268)in transgenic yeast cells could enhance their tolerance to multiple abiotic stress.In conclusion,this study advances our understanding of the mechanisms associated with the cold stress responses in peanut,and offers valuable gene resources for genetic improvement of abiotic stress tolerance in crops.

Isolation and identification of a marine killer yeast strain YF07b and cloning of the gene encoding killer toxin from the yeast

It was found that the marine yeast strain YF07b could secrete a large amount of killer toxin against a pathogenic yeast strain WCY which could cause milky disease in Portunus trituberculcttus. The marine yeast strain YF07b was identified to be Pichia anomala according to the results of routine yeast identification and 18S rDNA and ITS sequences. The gene encoding killer toxin in the marine yeast strain YF07b was amplified by PCR technology. After sequencing, the results show that an open reading frame, consisting of 1 281 bp, encoded a presumed protein of 427 amino acids. The sequence of the cloned gene was found to have 99% match with that of the gene encoding killer toxin in Pichia anomalas strain K. A signal peptide including 17 amino acids appeared in the N-terminal domain of the killer toxin. Therefore, the mature protein consisted of 410 amino acids, its molecular mass was estimated to be 47.4 ku and its isoelctronic point was 4.5.

Preparation of Organic Selenocystine Using Locally Isolated Bread Yeast

In contrast to the toxic inorganic forms of selenium to life at very low concentrations, the organic-selenium compounds are of considerable interest and several of them play essential roles in cell biochemistry and nutritional science. Se-yeast （Selenium-enriched yeast） is a common form of selenium used to supplement dietary intake of this important trace mineral. In the present study, we tried to prepare an organic selenocystine using locally isolated bread yeast （Saccharomyces cerevisiae）. A novel locally prepared date extract media enriched by addition of 0.2% KH2PO4 （potassium phosphate）, 0.6% ammonium sulfate was adopted as alternative culture media. Differences concentrations of selenium salt （30, 60, 120 and 240 lag/mL） were added to the yeast culture media. While the best concentration of selenium added was 30Bg/mL, it achieved optimal conditions for the growth of yeast and the production of red yeast growth identical to the standard. The products （organic selenocystine） were analyzed by HPLC （High Performance Liquid Chromatography） and AAS （Atomic Absorption Spectrophotometer） comparing with authentic standard obtained from Sigma. Results confirmed the formation of similar selenocystine products.

以分子生物学鉴定结果为“金标准”评估Rapid ID Yeast Plus及API20C AUX对酵母样真菌的鉴定效能

目的以分子生物学方法为"金标准"对两种商品化酵母样真菌鉴定产品Rapid ID Yeast Plus(简称RapID YST)及API20C AUX(简称API20C)的鉴定效能进行评估。方法从2010年中国医院侵袭性真菌感染监测网菌株库中筛选酵母样真菌25种,共计194株。其中,包含临床最常见的5种酵母样真菌(白念珠菌、热带念珠菌、光滑念珠菌、近平滑念珠菌、新生隐球菌)共130株,占研究总菌株数的67.0%。所有菌株已经过分子生物学方法准确鉴定至种水平。菌株复苏分纯后,严格按照产品操作指南,平行进行RapID YST和API20C鉴定。结果所研究菌株中,有181株(18种)在RapID YST鉴定菌种数据库中,所有在库菌株种及复合体鉴定正确率为87.8%(159/181)。相比,API鉴定菌种库包含菌株174株(18种),在库菌株种及复合体鉴定正确率为92.0%(160/174)。RapID YST与API20C对于5种临床常见的酵母样真菌的种鉴定正确率分别为93.1%和97.1%。对于库外菌株,RapID YST的鉴定错误率分别为23.1%(3/13),相比API20C的鉴定错误率为60.0%(12/20)。综合此次评估结果,二者对酵母样真菌的鉴定效能无显著差异(McNemar检验,P>0.05)。结论两种商品化产品对酵母样真菌的鉴定效能基本一致;相较而言,RapID YST在操作便捷性、检测时间方面具有较大优势。

Kinetic spectrophotometric determination of vanadium in steels based on the catalytic oxidation of thionine by potassium bromate

A sensitive and selective kinetic spectrophotometric method for the determination of V（V） was developed based on the catalytic oxidation of thionine by KBIO3 in 0.6 mol·L^-1 HaPO4 medium. The linear calibration range and detection limit at 25℃ were 0-0.5 μg·mL^-1 and 0.01 μg·mL^-1, respectively. In the presence of NaF and urea, most of the common ions did not interfere with the determination of V（V）. The proposed method was applied for the determination of vanadium in steels and satisfactory results were obtained.

Effects of yeast and yeast cell wall polysaccharides supplementation on beef cattle growth performance, rumen microbial populations and lipopolysaccharides production

This experiment was conducted to investigate the effects of live yeast and yeast cell wall polysaccharides on growth performance,rumen function and plasma lipopolysaccharides(LPS) content and immunity parameters of beef cattle.Forty Qinchuan cattle were randomly assigned to one of four treatments with 10 replicates in each treatment.The dietary treatments were: control diet(CTR),CTR supplemented with 1 g live yeast(2×10^10 live cell g^-1 per cattle per day(YST1),CTR supplemented with 2 g live yeast per cattle per day(YST2) and CTR supplemented with 20 g of yeast cell wall polysaccharides(30.0%≤β-glucan≤35.0%,and 28.0%≤mannanoligosaccharide≤32.0%) per cattle per day(YCW).The average daily gain was higher(P=0.023) and feed conversion ratio was lower(P=0.042) for the YST2 than the CTR.The digestibility of neutral detergent fiber(P=0.039) and acid detergent fiber(P=0.016) were higher in yeast supplemented groups.The acetic acid:propionic acid of the YST2 was lower compared with the CTR(P=0.033).Plasma LPS(P=0.032),acute phase protein haptoglobin(P=0.033),plasma amyloid A(P=0.015) and histamine(P=0.038) were lower in the YST2 compared with the CTR.The copies of fibrolytic microbial populations such as Fibrobacter succinogenes S85,Ruminococcus albus 7 and Ruminococcus flavefaciens FD-1 of the YST2 were higher(P<0.001),while the copies of typical lactate producing bacteria Streptococcus bovis JB1 was lower(P<0.001) compared with the CTR.Little differences were observed between the CTR,YST1 and YCW in growth performance,ruminal fermentation characteristics,microbial populations,immunity indices and total tract nutrient digestibility.It is concluded that the YST2 could promote fibrolytic microbial populations,decrease starch-utilizing bacteria,reduce LPS production in the rumen and LPS absorption into plasma and decrease inflammatory parameters,which can lead to an improvement in growth performance in beef cattle.

Detection for Transcriptional Activity of Alternaria Tenuissim Protein Elicitor in Yeast Two-hybrid System

The peaT1 gene fragment was amplified from pGEM-6p-l-peaT1 by PCR, and recovered target gene was cloned into pLexA vector. After digestion and sequencing, the bait vector pLexA-peaT1 was transformed into yeast strain EGY48 [p8op-lacZ] by PEG/LiAC, and the transcriptional activity of bait vector was detected. The results showed that recombinant bait plasmid pLexA-PEMG1 was constructed, for the two bands of recombinant bait plasmid in agarose gel eleetrophoresis were expected after digesting by restriction endonuclease EcoR I and Xho I. Therefore, the recombinant bait plasmid could be used in yeast two-hybrid system to screen a cDNA library.

Red Yeast Rice Increases Excretion of Bile Acids in Hamsters

Objective To investigate the hypocholesterolemic activity of red yeast rice （RYR） and its underlying mechanism. Methods Three groups of hamsters were fed either the control diet or one of the two experimental diets containing by weight 0.1% RYR （0.1RYR） or 0.3% RYR （0.3RYR）. Blood （0.5 mL） was collected from the retro-orbital sinus into a heparinized capillary tube at the end of week 0, 3, and 6. Plasma lipoproteins were measured using enzymatic kits, while fecal neutral and acidic sterols were quantified using a gas-liquid chromatography. Results Plasma total cholesterol was reduced by 12% in 0.1RYR group and by 18% in 0.3RYR group compared with the control value. Similarly, plasma triacylglycerol was decreased by 11% in 0.1RYR group and by 24% in 0.3RYR group. Western blotting analysis demonstrated that RYR had no effect on sterol regulatory element binding protein 2, fiver X receptor, 3-hydroxy-3-methylglutary-CoA reductase, LDL receptor, and cholesterol-7α-hydroxylase. HPLC analysis confirmed that RYR contained 0.88% monacolin K. It was recently found that RYR supplementation increased excretion of fecal acidic sterols by 34 folds compared with the conlrol value. Conclusion Hypocholesterolemic activity of RYR is mediated at least partially by enhancement of acidic sterol excretion.