Saccharomyces cerevisiae prevents postoperative recurrence of Crohn's disease modeled by ileocecal resection in HLA-B27 transgenic rats

BACKGROUND Postoperative recurrence(POR)after ileocecal resection(ICR)affects most Crohn's disease patients within 3-5 years after surgery.Adherent-invasive Escherichia coli(AIEC)typified by the LF82 strain are pathobionts that are frequently detected in POR of Crohn's disease and have a potential role in the early stages of the disease pathogenesis.Saccharomyces cerevisiae CNCM I-3856 is a probiotic yeast reported to inhibit AIEC adhesion to intestinal epithelial cells and to favor their elimination from the gut.AIM To evaluate the efficacy of CNCM I-3856 in preventing POR induced by LF82 in an HLA-B27 transgenic(TgB27)rat model.METHODS Sixty-four rats[strain F344,38 TgB27,26 control non-Tg(nTg)]underwent an ICR at the 12th wk(W12)of life and were sacrificed at the 18th wk(W18)of life.TgB27 rats were challenged daily with oral administration of LF82(109 colony forming units(CFUs)/day(d),n=8),PBS(n=5),CNCM I-3856(109 CFUs/d,n=7)or a combination of LF82 and CNCM I-3856(n=18).nTg rats receiving LF82(n=5),PBS(n=5),CNCM I-3856(n=7)or CNCM I-3856 and LF82(n=9)under the same conditions were used as controls.POR was analyzed using macroscopic(from 0 to 4)and histologic(from 0 to 6)scores.Luminal LF82 quantifications were performed weekly for each animal.Adherent LF82 and inflammatory/regulatory cytokines were quantified in biopsies at W12 and W18.Data are expressed as the median with the interquartile range.RESULTS nTg animals did not develop POR.A total of 7/8(87%)of the TgB27 rats receiving LF82 alone had POR(macroscopic score≥2),which was significantly prevented by CNCM I-3856 administration[6/18(33%)TgB27 rats,P=0.01].Macroscopic lesions were located 2 cm above the anastomosis in the TgB27 rats receiving LF82 alone and consisted of ulcerations with a score of 3.5(2-4).Seven out of 18 TgB27 rats(39%)receiving CNCM I-3856 and LF82 had no macroscopic lesions.Compared to untreated TgB27 animals receiving LF82 alone,coadministration of CNCM I-3856 and LF82 significantly reduced the macroscopic[3.5(2-4)vs 1(0-3),P=0.002]and histological lesions by more than 50%[4.5(3.3-5.8)vs 2(1.3-3),P=0.003].The levels of adherent LF82 were correlated with anastomotic macroscopic scores in TgB27 rats(r=0.49,P=0.006),with a higher risk of POR in animals having high levels of luminal LF82(71.4%vs 25%,P=0.02).Administration of CNCM I-3856 significantly reduced the levels of luminal and adherent LF82,increased the production of interleukin(IL)-10 and decreased the production of IL-23 and IL-17 in TgB27 rats.CONCLUSION In a reliable model of POR induced by LF82 in TgB27 rats,CNCM I-3856 prevents macroscopic POR by decreasing LF82 infection and gut inflammation.

Reducing Yield of Fusel Alcohols by Saccharomyces cerevisiae of Compound Mutagenesis Through UV-MPMS Method

Excessive fusel alcohol contents will cause the beer to produce off-flavors and cause dizziness and headaches.Reducing the contents of fusel alcohols in beer is very important to people's health.The excessive fusel alcohol contents in beer is a common problem in the industry.How to control the contents of fusel alcohols in a reasonable range is of great significance for improving beer quality.After one round of ultraviolet(UV)and one round of multifunctional plasma mutagenesis system(MPMS)mutagenesis,the yeast strains with lower fusel oil yield and more stablility could be screened.According to the relationship between the fusel alcohol Harris metabolic pathway of brewer's yeast and lactic acid metabolism,excellent strains were obtained by triple screening with lactic acid medium,calcium carbonate medium and 2,3,5-triphenyl tetrazolium chloride upper medium.The content of fusel alcohol in the finished beer fermentation test of screened strain Z43 was 52.1±0.142 mg•L^(-1),which was 43%lower than that of the starting strain,and other fermentation properties remained unchanged.After eight passages,it was verified that the strain was stable and heritable.These results showed that strain Z43 presented promising characteristics for use in the production of beer with a potentially low contents of fusel alcohols.

Effects of different forms of yeast Saccharomyces cerevisiae on growth performance,intestinal development,and systemic immunity in early-weaned piglets

The present study was conducted to determine effects of different forms of yeast （Saccharomyces cerevisiae, strain Y200007） on the growth performance, intestinal development, and systemic immunity in early-weaned piglets. A total of 96 piglets （14-d old, initial average body weight of 4.5 kg） were assigned to 4 dietary treatments： （1） basa diet without yeast （Control）; （2） basal diet supplemented with 3.00 g/kg live yeast （LY）; （3） basal diet supplemented with 2.66 g/kg heat-killed whole yeast （HKY）; and （4） basal diet supplemented with 3.00 g/kg superfine yeast powders （SFY）. Diets and water were provided ad libitum to the piglets during 3-week experiment. Growth performance of piglets was measured weekly. Samples of blood and small intestine were collected at days 7 and 21 of experiment. Dietary supplementation with LY and SFY improved G：F of piglets at days ]-21 of the experiment （P 〈 0.05） compared to Control group. Serum concentrations of growth hormone （GH）, triiodothyronine （T3）, tetraiodothyronine （T4）, and insulin growth factor 1 （iGF-1） in piglets at day 21 of the experiment were higher when fed diets supplemented with LY and SFY than those in Control group （P 〈 0.05）. Compared to Control group, contents of serum urea nitrogen of piglets were reduced by the 3 yeast-supplemented diets （P 〈 0.05）. Diets supplemented with LY increased villus height and villus-to-crypt ratio in duodenum and jejunum of piglets （P 〈 0.05） compared to other two groups at day 7 of the experiment. Feeding diets supplemented with LY and SFY increased （P 〈 0.05） serum concentrations of IgA, IL-2, and IL-6 levels in piglets compared to Control. The CD4＋/CD8＋ ratio and proliferation of T-lymphocytes in piglets fed diets supplemented with LY were increased compared to that of Control group at day 7 of the experiment （P 〈 0.05）. In conclusion, dietary supplementation with both LY and SFY enhanced feed conversion, small intestinal development, and systemic immunity in early-weaned piglets, with better improvement in feed conversion by dietary supplementation with LY, while dietary supplementation with SFY was more effective in increasing systemic immune functions in early-weaned piglets.

Feeding a Saccharomyces cerevisiae fermentation product improves udder health and immune response to a Streptococcus uberis mastitis challenge in mid-lactation dairy cows

Background:We aimed to characterize the protective effects and the molecular mechanisms of action of a Saccharomyces cerevisiae fermentation product(NTK)in response to a mastitis challenge.Eighteen mid-lactation multiparous Holstein cows(n=9/group)were fed the control diet(CON)or CON supplemented with 19 g/d NTK for 45 d(phase 1,P1)and then infected in the right rear quarter with 2500 CFU of Streptococcus uberis(phase 2,P2).After 36-h,mammary gland and liver biopsies were collected and antibiotic treatment started until the end of P2(9 d post challenge).Cows were then followed until day 75(phase 3,P3).Milk yield(MY)and dry matter intake(DMI)were recorded daily.Milk samples for somatic cell score were collected,and rectal and udder temperature,heart and respiration rate were recorded during the challenge period(P2)together with blood samples for metabolite and immune function analyses.Data were analyzed by phase using the PROC MIXED procedure in SAS.Biopsies were used for transcriptomic analysis via RNA-sequencing,followed by pathway analysis.Results:DMI and MY were not affected by diet in P1,but an interaction with time was recorded in P2 indicating a better recovery from the challenge in NTK compared with CON.NTK reduced rectal temperature,somatic cell score,and temperature of the infected quarter during the challenge.Transcriptome data supported these findings,as NTK supplementation upregulated mammary genes related to immune cell antibacterial function(e.g.,CATHL4,NOS2),epithelial tissue protection(e.g.IL17C),and anti-inflammatory activity(e.g.,ATF3,BAG3,IER3,G-CSF,GRO1,ZFAND2A).Pathway analysis indicated upregulation of tumor necrosis factorα,heat shock protein response,and p21 related pathways in the response to mastitis in NTK cows.Other pathways for detoxification and cytoprotection functions along with the tight junction pathway were also upregulated in NTK-fed cows.Conclusions:Overall,results highlighted molecular networks involved in the protective effect of NTK prophylactic supplementation on udder health during a subclinical mastitic event.

Integrated Expression of the Oenococcus oeni mleA Gene in Saccharomyces cerevisiae

Malolactic enzyme is the function enzyme which catalyses the reaction for L-malate converting to L-lactic during malolactic fermentation （MLF）. In this paper, researches concerning the malolactic enzyme gene mleA cloned from a patent strain Oenococcus oeni SD-2a screened in Chinese wine and integrated expressing in Saccharomyces cerevisiae were performed in order to carry out both alcoholic fermentation （AF） and malolactic fermentation （MLF） during winemaking, with a view to achieving a better control of MLF in enology. To construct the expression plasmid named pYILmleA, cloned mleA gene, PGK1 promoter, and ADH1 terminator were ligated and inserted into integrating vector YIp5. Yeast transformants were screened on SD/-Ura and identified by auxotrophic test, mating type test, and colony PCR. Target protein was detected by SDS-PAGE and the targeted gene integrated to the chromosome was detected by dot bloting hybridization. After the transformant was cultured in SD/-Ura adding glucose （10%） and L-malate （5 648 mg L-1） for 4 d, the culture supernatant was collected and L-malate and L-lactic acid contents were detected by HPLC. 1 278-1 312 mg L-1 L-lactic acids were detected, while the comparative drop rates of L-malate were 20.18-20.85%. L-malate and L-lactic contents of the transformants showed extra significant difference and significant difference with the control ones by t-test respectively. The result indicated that the functional expression was achieved in recombinants S. cerevisiae.

Effect of yeast Saccharomyces cerevisiae supplementation on serum antioxidant capacity, mucosal sIgA secretions and gut microbial populations in weaned piglets

This study was conducted to determine the effect of different forms of yeasts Saccharomyces cerevisiae supplementation on serum antioxidant capacity, mucosal secretory immunoglobulin A（s Ig A） secretions and gut microbial populations in weaned piglets. A total of 96 piglets weaned at 14 d of age were randomly allotted to 4 dietary treatments：（1） basal diet without yeast（Control）;（2） basal diet supplemented with 3.00 g kg–1 live yeast（LY）;（3） basal diet supplemented with 2.66 g kg–1 heat-killed whole yeast（HKY）; and（4） basal diet supplemented with 3.00 g kg–1 superfine yeast powders（SFY）. Each treatment had 4 replicates（pens）, with 6 piglets per replicate. The experiment lasted for 3 wk. At d 7 and 21 of the experiment, the samples of serum, mucosa and mesenteric lymph node（MLN） from jejunum, and digesta from the ileum and cecum were collected for determinations. Compared with the Control, dietary SFY supplementation increased serum superoxide dismutase（SOD） activity and lysozyme levels at d 7, and jejunum mucosal s Ig A secretions at d 21 of the experiment（P〈0.05）. Dietary LY supplementation increased serum SOD activity and jejunum mucosal s Ig A secretions, but decreased serum malondialdehyde（MDA） concentration at d 7 and 21（P〈0.05）. Piglets fed diets supplemented with LY and SFY had lower p H values and decreased numbers of Escherichia coli in the ileum and cecum contents at d 21 compared with the Control（P〈0.05）. Moreover, the ratio of Lactobacilli to E. coli in the ileum and cecum contents was increased by dietary LY and SFY supplementations（P〈0.05）. Collectively, different forms of yeasts, especially LY and SFY, may modulate body antioxidant capacity and enhance the intestinal immunity by regulation of secretions of mucosal s Ig A and reduction of pathogenic bacteria colonization, thus improving intestinal health of weaned piglets.

Effects of Saccharomyces cerevisiae fermentation products on performance and rumen fermentation and microbiota in dairy cows fed a diet containing low quality forage

Background： A possible option to meet the increased demand of forage for dairy industry is to use the agricultural byproducts, such as corn stover. However, nutritional value of crop residues is low and we have been seeking technologies to improve the value. A feeding trial was performed to evaluate the effects of four levels of Saccharomyces cerevisiae fermentation product（SCFP; Original XP; Diamond V） on lactation performance and rumen fermentation in mid-lactation Holstein dairy cows fed a diet containing low-quality forage. Eighty dairy cows were randomly assigned into one of four treatments： basal diet supplemented with 0, 60, 120, or 180 g/d of SCFP per head mixed with 180, 120, 60, or 0 g of corn meal, respectively. The experiment lasted for 10 wks, with the first 2 weeks for adaptation.Results： Dry matter intake was found to be similar（P 〉 0.05） among the treatments. There was an increasing trend in milk production（linear, P ≤ 0.10） with the increasing level of SCFP supplementation, with no effects on contents of milk components（P 〉 0.05）. Supplementation of SCFP linearly increased（P 〈 0.05） the N conversion, without affecting rumen pH and ammonia-N（P 〉 0.05）. Increasing level of SCFP linearly increased（P 〈 0.05） concentrations of ruminal total volatile fatty acids, acetate, propionate, and butyrate, with no difference in molar proportion of individual acids（P 〉 0.05）. The population of fungi and certain cel ulolytic bacteria（Ruminococcus albus, R. flavefaciens and Fibrobacter succinogenes）increased linearly（P 〈 0.05） but those of lactate-utilizing（Selenomonas ruminantium and Megasphaera elsdeni） and lactate-producing bacteria（Streptococcus bovis） decreased linearly（P ≤ 0.01） with increasing level of SCFP. The urinary purine derivatives increased linearly（P 〈 0.05） in response to SCFP supplementation, indicating that SCFP supplementation may benefit for microbial protein synthesis in the rumen.Conclusions： The SCFP supplementation was effective in maintaining milk persistency of mid-lactation cows receiving diets containing low-quality forage. The beneficial effect of SCFP could be attributed to improved rumen function; 1）microbial population shift toward greater rumen fermentation efficiency indicated by higher rumen fungi and cel ulolytic bacteria and lower lactate producing bacteria, and 2） rumen microbial fermentation toward greater supply of energy and protein indicated by greater ruminal VFA concentration and increased N conversion. Effects of SCFP were dose-depended and greater effects being observed with higher levels of supplementation and the effect was more noticeable during the high THI environment.

Saccharomyces cerevisiae CNCM I-3856 in irritable bowel syndrome: An individual subject meta-analysis

AIM To confirm previous conclusions on Saccharomyces cerevisiae(S. cerevisiae) CNCM I-3856 for irritable bowel syndrome(IBS) management.METHODS An individual patient data meta-analysis was performed on two randomized clinical trials studying the effect of S. cerevisiae CNCM I-3856 supplementation on gastrointestinal(GI) symptoms in IBS subjects. A total of 579 IBS subjects were included. Outcomes were the daily Likert scale scores of abdominal pain/discomfort and bloating [area under the curve(AUC) and weekly means], responder status, and bowel movements(stool frequency and consistency). Statistical analyses were conducted in Intent to Treat(ITT) population, IBS-C subjects and IBS-C subjects with an abdominal pain/discomfort score higher than or equal to 2 at baseline("IBS-C ≥ 2 subpopulation").RESULTS S. cerevisiae CNCM I-3856 significantly improved abdominal pain/discomfort and bloating during the second month of supplementation [AUC(W5-W8)]with improvement up to the minimal clinically relevant threshold of 10%: a 12.3% reduction of abdominal pain/discomfort in the ITT population compared to the Placebo group(P = 0.0134) has been observed. In the IBS-C ≥ 2 subpopulation, there were a 13.1% reduction of abdominal pain/discomfort and a 14.9% reduction of bloating compared to the Placebo group(P = 0.0194 and P = 0.0145, respectively). GI symptoms significantly decreased during supplementation but no statistical differences were reported between groups at the end of the supplementation period. Responder status was defined as a subject who experienced a decrease of 1 arbitrary unit(a.u.) or 50% of the abdominal discomfort score from baseline for at least 2 wk out of the last 4 wk of the study. A significant difference between groups was reported in the ITT population, when considering the first definition: subjects in the Active group had 1.510 higher odds to be a responder(reduction of 1 a.u. of abdominal pain/discomfort) compared with subjects in the Placebo group(P = 0.0240). At the end of supplementation period, stool consistency in the Active group of the ITT population was significantly improved and classified as "normal" compared to Placebo(respectively 3.13 ± 1.197 a.u. vs 2.58 ± 1.020 a.u., P = 0.0003). Similar results were seen in the IBS-C ≥ 2 subpopulation(Active group: 3.14 ± 1.219 a.u. vs Placebo group: 2.59 ± 1.017 a.u., P = 0.0009).CONCLUSION This meta-analysis supports previous data linking S. cerevisiae I-3856 and improvement of GI symptoms, in IBS overall population and in the IBS-C and IBS-C ≥ 2 subpopulations.

Construction of Saccharomyces cerevisiae Strain Stably Expressing a Fusion Protein Containing Ten Tandem Recombinant Human Glucagon-like Peptide-1 Analogues

The recombinant Saccharomyces cerevisiae strain stably expressing recombinant human glucagon-like peptide-l（rhGLP-1） analogue, as a potential oral drug delivery system for diabetes type II treatment, was successfully constructed by the homologous recombination between chromosomal DNA and yeast and integrating vector pNK-GLP containing yeast ribosomal DNA fragments. The amount of rhGLP-I analogue fusion protein in transformant SG2 reached ca. 0.84 mg per gram of packed cells when SG2 was grown for 24 h in the YPD medium with a inoculum and medium ratio of 1：1. Oral administration of 5 g lyophilized SG2/kg to hyperglycemic rats decreased serum glucose from （24.8±1.40） to （21.2±1.36） mmol/L.

Parameter Optimization for Enhancement of Ethanol Yield by Atmospheric Pressure DBD-Treated Saccharomyces cerevisiae

In this study, Saccharomyces cerevisiae （S. cerevisiae） was exposed to dielectric barrier discharge plasma （DBD） to improve its ethanol production capacity during fermenta- tion. Response surface methodology （RSM） was used to optimize the discharge-associated pa- rameters of DBD for the purpose of maximizing the ethanol yield achieved by DBD-treated S. cerevisiae. According to single factor experiments, a mathematical model was established using Box-Behnken central composite experiment design, with plasma exposure time, power supply volt- age, and exposed-sample volume as impact factors and ethanol yield as the response. This was followed by response surface analysis. Optimal experimental parameters for plasma discharge- induced enhancement in ethanol yield were plasma exposure time of 1 rain, power voltage of 26 V, and an exposed sample volume of 9 mL. Under these conditions, the resulting yield of ethanol was 0.48 g/g, representing an increase of 33% over control.

Effects of antibacterial compounds produced by Saccharomyces cerevisiae in Koumiss on pathogenic Escherichia coli O8 and its cell surface characteristics

The effects of antibacterial compounds produced by Saccharomyces cerevisiae in Koumiss on pathogenic Escherichia coli O8 and its cell surface characteristics were investigated.S.cerevisiae isolated from Koumiss produced antibacterial compounds which were active against pathogenic E.coli O8 as determined by the Oxford cup method.The aqueous phases from S.cerevisiae at p H=2.0（S2）and pH=8.0（S8）were extracted and tested,respectively.The organic acids of S2 and S8 were determined by high performance liquid chromatography（HPLC）,and the concentrations of killer toxins were determined by enhanced bicinchoninic acid（BCA）Protein Assay Kit.The minimum inhibition concentration（MIC）and the minimum bactericidal concentration（MBC）of S2 and S8 on E.coli O8 were determined by the broth microdilution method.The effects of S2 and S8 on the growth curve of E.coli O8 were determined by turbidimetry,and the hydrophobicities of E.coli O8 cell surface were determined using the microbial adhesion to solvents method,the permeation of E.coli O8 cell membrane were determined by the o-nitrophenyl-β-D-galactoside（ONPG）method.Aqueous phases at pH 2.0 and 8.0had larger inhibition zones and then S2 and S8 were obtained by freeze-drying.The main component in S2 was citric acid and it was propanoic acid in S8.Other organic acids and killer toxins were also present.Both the MICs of S2 and S8 on E.coli O8 were 0.025 g m L^-1,the MBCs were 0.100 and 0.200 g m L^-1,respectively.The normal growth curve of E.coli O8was S-shaped,however,it changed after addition of S2 and S8.E.coli O8 was the basic character,and had a relatively hydrophilic surface.The hydrophobicity of E.coli O8 cell surface and the permeation of E.coli O8 cell membrane were increased after adding S2 and S8.The present study showed that S2 and S8 inhibit the growth of pathogenic E.coli O8and influence its cell surface characteristics.

Saccharomyces cerevisiae I-3856 in irritable bowel syndrome with predominant constipation

BACKGROUND Probiotics are a promising solution for managing irritable bowel syndrome(IBS).Saccharomyces cerevisiae(S.cerevisiae)I-3856 has already demonstrated beneficial effects in IBS subjects,particularly in IBS with predominant constipation(IBS-C).AIM To confirm the efficacy of S.cerevisiae I-3856 in the management of gastrointestinal symptoms in IBS-C.METHODS A randomized,double-blind,placebo-controlled clinical study was performed in a total of 456 subjects.After a run-in period,subjects were randomly assigned to the group receiving S.cerevisiae I-3856(8×109 CFU daily)or the placebo for 8 wk,and they performed daily self-evaluations of gastrointestinal symptoms.The primary objective was to assess the effect of the probiotic on abdominal pain.The secondary objectives were the evaluation of other gastrointestinal symptoms,bowel movement frequency and consistency,and quality of life(QOL).RESULTS A significantly higher proportion of abdominal pain responders was reported in the Probiotic group(45.1%vs 33.9%,P=0.017).A nonsignificant difference in the area under the curve for abdominal pain over the second month of supplementation was observed in subjects receiving probiotic vs placebo[P=0.073,95%CI:-0.59(-1.23;0.05)].No statistically significant differences were reported in the evolution of bowel movement frequency and stool consistency between the groups.After 8 wk of supplementation,the overall QOL score was significantly higher in the Probiotic group than in the Placebo group[P=0.047,95%CI:3.86(0.52;7.20)].Furthermore,exploratory analyses showed statistically significant and clinically relevant improvements in QOL scores in abdominal pain responders vs nonresponders.CONCLUSION The results of this clinical study confirmed the abdominal pain alleviation properties of S.cerevisiae I-3856 in IBS-C.Abdominal pain relief was associated with improved QOL.ClinicalTrials.gov identifier:NCT03150212.

Characteristics of Zn^(2+) Biosorption by Saccharomyces cerevisiae

Objective To investigate the characteristics of Zn^2＋ biosorption and the release of cations during the process of Zn^2＋ biosorption by intact cells of Saccharomyces cerevisiae. Methods The batch adsorption test was used to study the biosorption equilibrium and isotherm. Zn^2＋ concentration was measured with atomic adsorption spectrophotometer （AAS） AAS 6.Vario. Results When the initial concentration of Zn^2＋ ranged between 0.08 and 0.8 retool/L, the initial pH was natural （about 5.65）, the sorbent concentration was about 1 g/L and the capacity ofZn〉 biosorption was from 74.8 to 654.8 μmol/g. The pH value increased by 0.55-1.28 and the intracellular cations （K^＋, Mg^2＋, Na^＋, Ca〉） of the cells were re/eased during the process of Zn〉 biosorption. Conclusion Ion exchange was one of the mechanisms for Zn^2＋ biosorption. The biomass of Saccharomyces cerevisiae is a potential biosorbent for the removal of Zn^2＋ from aqueous solution. More work needs to be done before putting it into practical application.

Asymmetric bioreduction of γ- and δ-keto acids by native carbonyl reductases from Saccharomyces cerevisiae

Optically pure(R)-γ-and(R)-δ-lactones can be prepared by intramolecular cyclization of chiral hydroxy acids/esters reduced asymmetrically from γ-and δ-keto acids/esters using Saccharomyces cerevisiae(S.cerevisiae) as a whole-cell biocatalyst.However,some of the enzymes catalyzing these reactions in S.cerevisiae are still unknown up to date.In this report,two carbonyl reductases,OdCRl and OdCR2,were successfully discovered,and cloned from S.cerevisiae using a genome-mining approach,and overexpressed in Escherichia coli(E.coli).Compared with OdCR1,OdCR2 can reduce 4-oxodecanoic acid and 5-oxodecanoic acid asymmetrically with higher stereoselectivity,generating(R)-γ-decalactone(99% ee) and(R)-δ-decalactone(98% ee) in 85% and 92%yields,respectively.This is the first report of native enzymes from S.cerevisiae for the enzymatic synthesis of chiral γ-and δ-lactones which is of wide uses in food and cosmetic industries.

Heterologous Expression of Amylase Gene from Saccharomycopsis fibuligera in an Industrial Strain of Saccharomyces cerevisiae

An α-amylase encoding gene was amplified by polymerase chain reaction from Saccharomycopsis fibuligeru and inserted into a shuttle vector YEp352,together with the yeast phosphoglycerate kinase 1 prumoter and a-factor signal gene. The recombinant expression plasmid pLA8α was transformed into an industrial strain of Saccharomycopsis cerevisiae Sc-11. The activity of the α-amylase produced by the transformant Sc-11-pLA8α was 6.3 U/mL and the starch utilization rate in YPS medium was 42%. The purified amylase was analyzed by SDS-PAGE,showing a molecular weight of 55×10^3 protein band. Furthermore, the residual sugar, ethanol and some volatile compounds in the fermented worts under simulating brewing conditions were determined by chromatographic analyses. The fermentation characteristics of Sc-ll-pLA8α were similar to that of Sc-ll and only minor changes in the concentration of flavor compounds could be observed.

A novel approach to regulate cell membrane permeability for ATP and NADH formation in Saccharomyces cerevisiae induced by air cold plasma

Air cold plasma has been used as a novel method for enhancing microbial fermentation. The aim of this work was to explore the effect of plasma on membrane permeability and the formation of ATP and NADH in Saccharomyces cerevisiae, so as to provide valuable information for largescale application of plasma in the fermentation industry. Suspensions of S. cerevisiae cells were exposed to air cold plasma for 0, 1, 2, 3, 4 and 5 min, and then subjected to various analyses prior to fermentation （Oh） and at the 9 and 21 h stages of fermentation. Compared with nonexposed cells, cells exposed to plasma for 1 min exhibited a marked increase in cytoplasmic free Ca2＋ concentration as a result of the significant increase in membrane potential prior to fermentation. At the same time, the ATP level in the cell suspension decreased by about 40%, resulting in a reduction of about 60% in NADH prior to culturing. However, the levels of ATP and NADH in the culture at the 9 and 21 h fermentation stages were different from the level at 0 h. Taken together, the results indicated that exposure of S. cerevisiae to air cold plasma could increase its cytoplasmic free Ca2＋ concentration by improving the cell membrane potential, consequently leading to changes in ATP and NADH levels.

Identification of acetic-acid tolerance of Saccharomyces cerevisiae strains by microsatellite markers

The aim of this paper is to use the microsatellites to evaluate acid-tolerance in Saccharomyces(S.) cerevisiae. Microsatellites have been widely used as the molecular marker to classify and identify S. cerevisiae strains, analyze genetic relationships among strains, and reveal genetic diversity of S. cerevisiae populations. In this paper, 25 key microsatellites of S. cerevisiae from 44 industrial yeast strains are investigated in the medium withconcentration gradients of acetic acid. Based on the analysis of correlations between the key microsatellite loci repeat numbers and acid-tolerance of the strains, the allele size of 4P14 a and 10P13 is positively related to acid-tolerance(p ? 0.05), the allele size of AT-X, 4P1 a and 10P8 are significantly negatively related to acid-tolerance(p ? 0.01). The above results provide informations on the molecular biodiversity of S. cerevisiae strains and can be a theoretical guidance for molecular marker assisted selection.

The effect of Saccharomyces cerevisiae on digestion and mortality in the volcano rabbit(Romerolagus diazi)

An experiment was conducted to evaluate whether supplementation with a probiotic could enhance digestion and reduce mortality in the volcano rabbit in captivity. Two enclosures at Chapultepec Zoo, Mexico（114 individuals） were used in a crossover design（two periods of 60 days） with the following treatments： control group and supplementation with Saccharomyces cerevisiae（2×108 CFU/exhibit/day）. Supplementation with the probiotic negatively affected（P〈0.01） the digestibility of dry matter, organic matter, neutral detergent fiber（NDF） and energy. Mortality increased（P〈0.04） following supplementation with the probiotic（4.26% vs. 8.89%）, primarily in the juvenile rabbits. The results indicate that yeast supplementation in the volcano rabbit negatively affects digestion and mortality in captivity.

Using the Phosphomannose Isomerase (PMI) Gene from Saccharomyces cerevisiae for Selection in Rice Transformation

The phosphomannose isomerase （PMI） gene from Saccharomyces cerevisiae acted as selectable marker and mannose acted as selective agent for the production of transgenic plants of rice （Oryza sativa L.） via Agrobacterium-mediated transformation. The concentration of mannose during the selection was stepwise increased, 5 g L-1 mannose combined with 15 g L-1 sucrose and 500 mg L-1 cefotaxime was used in the initial selection stage, then the concentration of mannose was increased to 11 g L-1, the highest transformation rate was 20.0%. The integration of PMI gene was confirmed by PCR, and the result of RT-PCR assay proved that the intron of PMI gene can be excised correctly during RNA splicing. 13- Glucuronidase （GUS） activity analysis confirmed the expression of GUS gene. All those means the PMI gene from yeast can be used as a selectable marker in rice transformation.

Antifungal activity of various essential oils against Saccharomyces cerevisiae depends on disruption of cell membrane integrity

Antifungal activity and mode of action of nine essential oils(EOs)against S.cerevisiae cells were examined.Antifungal effects of commercial lemon peel,orange peel,tea tree,turpentine,rosemary,peppermint,thyme,oregano and clove oils were determined through Minimum Inhibitory Concentration(MIC),Minimum Fungicidal Concentration(MFC)and inhibition zone measurements.The most effective oil was turpentine oil.Orange peel,thyme and oregano oils were also effective,according to MIC and MFC.Inhibition zone measurements,also revealed oregano,orange peel,thyme,turpentine and clove oils as most efficient ones.Later,membrane damage of yeast cells was studied by measuring the extracellular pH and conductivity in a concentration dependent manner.Orange peel,turpentine,thyme and oregano oils caused a clear increase in extracellular pH of glucose-induced yeast cells and induced an increase in extracellular conductivity.These results point to the deterioration of yeast cell membrane integrity upon exposure to EOs.Since these oils can be used as food preservatives and pharmaceutical agents,it is very important to understand their mode of action and their main target sites in the cell.Thus this research not only opens new perspectives to understand antifungal activity mechanisms of EOs,but also help widen their use.