Zygosaccharomyces rouxii is a salt-tolerant yeast species capable of removing cadmium(Cd) pollutant from aqueous solution. Presently, the physiological characteristics of Z. rouxii under the stress of sodium chloride(...Zygosaccharomyces rouxii is a salt-tolerant yeast species capable of removing cadmium(Cd) pollutant from aqueous solution. Presently, the physiological characteristics of Z. rouxii under the stress of sodium chloride(NaCl) and Cd are poorly understood. This study investigated the effects of NaCl and Cd on the growth, oxidative stress and antioxidant enzyme activities of Z. rouxii after stress treatment for 24 h. Results showed that NaCl or Cd alone negatively affected the growth of Z. rouxii, but the growth-inhibiting effect of Cd on Z. rouxii was reduced in the presence of NaCl. Flow cytometry assay showed that under Cd stress, NaCl significantly reduced the production of reactive oxygen species(ROS) and cell death of Z. rouxii compared with those in the absence of NaCl. The activities of superoxide dismutase(SOD), catalase(CAT), and peroxidase(POD) of Z. rouxii were significantly enhanced by 2%–6% NaCl, which likely contributed to the high salt tolerance of Z. rouxii. The POD activity was inhibited by 20 mg L-1Cd while the SOD and CAT activities were enhanced by 8 mg L-1 Cd and inhibited by 20 mg L-1 or 50 mg L-1 Cd. The inhibitory effect of high-level Cd on the antioxidant enzyme activities of Z. rouxii was counteracted by the combined use of NaCl, especially at 6%. This probably accounted for the decrease in Cd-induced ROS production and cell death of Z. rouxii after incubation with NaCl and Cd. Our work provided physiological clues as to the use of Z. rouxii as a biosorbent for Cd removal from seawater and liquid highly salty food.展开更多
The high-glucose tolerance of yeast is the main factor determining the efficiency of high-density alcohol fermentation.Zygosaccharomyces mellis LGL-1 isolated from honey could survive under 700 g/L high-glucose stress...The high-glucose tolerance of yeast is the main factor determining the efficiency of high-density alcohol fermentation.Zygosaccharomyces mellis LGL-1 isolated from honey could survive under 700 g/L high-glucose stress and its tolerant characteristics were identified in our previous study.This study was performed to explore and clarify the high-glucose tolerance mechanism of Z.mellis LGL-1.Comparative transcriptomic analysis was used to analyze the genes with differential expression in Z.mellis under high-glucose conditions of 300,500 and 700 g/L.With 300 g/L samples as reference,there were 937 and 2380 differentially expressed genes(DEGs)in the 500 and 700 g/L samples,respectively.Meanwhile,there was 825 significant DEGs in the 700 g/L samples compared with that of the 500 g/L samples.The result revealed that transcriptional changes in multiple metabolic pathways occur in response to high-glucose stress.q-RT PCR analysis further confirmed that several stress response pathways,such as the high osmolarity glycerol mitogen-activated protein kinase(HOG-MAPK)signal transduction pathway,trehalose synthesis pathway and oxidative stress response are closely related to high-glucose tolerance in Z.mellis.This study clarifies mechanisms of Z.mellis in response to high-glucose osmotic stress,providing theoretical basis for the process control of high-density alcohol fermentation.展开更多
The Zygosaccharomyces rouxii is a kind of fermentation yeast which yield flavoring substance in the production of soy sauce. In order to the overexpression of the target protein in wild type strains, we choose PYEs2.0...The Zygosaccharomyces rouxii is a kind of fermentation yeast which yield flavoring substance in the production of soy sauce. In order to the overexpression of the target protein in wild type strains, we choose PYEs2.0 as the original carrier, the acyl-coA binding protein (ACBP) and GFP gene have been cloned in the multiple cloning site. The screening of labeled URA3 gene was replaced by KanMX gene which anti G418. The vector was obtained through the screening of G418 at the concentration of 25 ug/ml.展开更多
Diversity of yeasts in association with bees and their food sources has been explored during the last decade.In Thailand,there has been no study of yeast identification in honey and bees.Hence,a total of 186 yeast str...Diversity of yeasts in association with bees and their food sources has been explored during the last decade.In Thailand,there has been no study of yeast identification in honey and bees.Hence,a total of 186 yeast strains were isolated from 37 honey samples of 12 different bee species.On the basis of morphological and physiological characteristics,55 representative strains were chosen and identified by sequence analysis of the 26S rDNA D1/D2 domain and the ITS region.The data were compared with the published sequences and the results showed the occurrence of 19 ascomycetous and 1 basidiomycetous yeast species.Six strains of the new species were isolated.Phylogenetic analysis of the 26S rDNA D1/D2 sequence revealed that they were conspecific and most closely related to Zygosaccharomyces mellis.Based on the ITS sequence,the new species was clustered with the type"and clearly distinguished from the type!.Sequence analysis of combined ITS-26S rDNA D1/D2 showed similar results.The occurrence of these two types,with a divergence of more than 1%in their sequences,and low DNA relatedness among them suggested that members of the typeβcan be regarded as separate species.An analysis of the morphological and physiological characteristics was performed.Ascospore formation was observed on acetate agar and Gorodkowa agar.The new Zygosaccharomyces species differed physiologically from Z.mellis in 4 assimilation tests.This data supports the hypothesis that the new species,Zygosaccharomyces siamensis,is a novel ascosporogenous yeast.The type strain is JCM 16825T(=CBS 12273T)and a description is given here.展开更多
基金the financial support of the National Natural Science Foundation of China (Grant Nos. 31101330 and 30972289)the Natural Science Foundation of Shandong Province in China (Grant No. ZR2010CM043)+1 种基金the International Joint Research Program (Grant No. 2010DFA31330)the Program for Changjiang Scholars and Innovative Research Team in University (Grant No. IRT1188)
文摘Zygosaccharomyces rouxii is a salt-tolerant yeast species capable of removing cadmium(Cd) pollutant from aqueous solution. Presently, the physiological characteristics of Z. rouxii under the stress of sodium chloride(NaCl) and Cd are poorly understood. This study investigated the effects of NaCl and Cd on the growth, oxidative stress and antioxidant enzyme activities of Z. rouxii after stress treatment for 24 h. Results showed that NaCl or Cd alone negatively affected the growth of Z. rouxii, but the growth-inhibiting effect of Cd on Z. rouxii was reduced in the presence of NaCl. Flow cytometry assay showed that under Cd stress, NaCl significantly reduced the production of reactive oxygen species(ROS) and cell death of Z. rouxii compared with those in the absence of NaCl. The activities of superoxide dismutase(SOD), catalase(CAT), and peroxidase(POD) of Z. rouxii were significantly enhanced by 2%–6% NaCl, which likely contributed to the high salt tolerance of Z. rouxii. The POD activity was inhibited by 20 mg L-1Cd while the SOD and CAT activities were enhanced by 8 mg L-1 Cd and inhibited by 20 mg L-1 or 50 mg L-1 Cd. The inhibitory effect of high-level Cd on the antioxidant enzyme activities of Z. rouxii was counteracted by the combined use of NaCl, especially at 6%. This probably accounted for the decrease in Cd-induced ROS production and cell death of Z. rouxii after incubation with NaCl and Cd. Our work provided physiological clues as to the use of Z. rouxii as a biosorbent for Cd removal from seawater and liquid highly salty food.
基金Key-Area Research and Development Program of Guangdong Province(2018B020206001)Guangdong Provincial Agricultural Science and Technology Innovation and Extension Project in 2019(2019KJ101)+1 种基金National key research and development plan(2018YFC1604105)National Natural Science Foundation of China(81703053).
文摘The high-glucose tolerance of yeast is the main factor determining the efficiency of high-density alcohol fermentation.Zygosaccharomyces mellis LGL-1 isolated from honey could survive under 700 g/L high-glucose stress and its tolerant characteristics were identified in our previous study.This study was performed to explore and clarify the high-glucose tolerance mechanism of Z.mellis LGL-1.Comparative transcriptomic analysis was used to analyze the genes with differential expression in Z.mellis under high-glucose conditions of 300,500 and 700 g/L.With 300 g/L samples as reference,there were 937 and 2380 differentially expressed genes(DEGs)in the 500 and 700 g/L samples,respectively.Meanwhile,there was 825 significant DEGs in the 700 g/L samples compared with that of the 500 g/L samples.The result revealed that transcriptional changes in multiple metabolic pathways occur in response to high-glucose stress.q-RT PCR analysis further confirmed that several stress response pathways,such as the high osmolarity glycerol mitogen-activated protein kinase(HOG-MAPK)signal transduction pathway,trehalose synthesis pathway and oxidative stress response are closely related to high-glucose tolerance in Z.mellis.This study clarifies mechanisms of Z.mellis in response to high-glucose osmotic stress,providing theoretical basis for the process control of high-density alcohol fermentation.
文摘The Zygosaccharomyces rouxii is a kind of fermentation yeast which yield flavoring substance in the production of soy sauce. In order to the overexpression of the target protein in wild type strains, we choose PYEs2.0 as the original carrier, the acyl-coA binding protein (ACBP) and GFP gene have been cloned in the multiple cloning site. The screening of labeled URA3 gene was replaced by KanMX gene which anti G418. The vector was obtained through the screening of G418 at the concentration of 25 ug/ml.
基金This work was funded by the Thai Government Science and Technology Scholarship for Ph.D.Study,awarded to S.Saksinchai,grant RSA5280010 from the Thailand Research Fund,the National Research University,and Office of the Higher Education Commission.
文摘Diversity of yeasts in association with bees and their food sources has been explored during the last decade.In Thailand,there has been no study of yeast identification in honey and bees.Hence,a total of 186 yeast strains were isolated from 37 honey samples of 12 different bee species.On the basis of morphological and physiological characteristics,55 representative strains were chosen and identified by sequence analysis of the 26S rDNA D1/D2 domain and the ITS region.The data were compared with the published sequences and the results showed the occurrence of 19 ascomycetous and 1 basidiomycetous yeast species.Six strains of the new species were isolated.Phylogenetic analysis of the 26S rDNA D1/D2 sequence revealed that they were conspecific and most closely related to Zygosaccharomyces mellis.Based on the ITS sequence,the new species was clustered with the type"and clearly distinguished from the type!.Sequence analysis of combined ITS-26S rDNA D1/D2 showed similar results.The occurrence of these two types,with a divergence of more than 1%in their sequences,and low DNA relatedness among them suggested that members of the typeβcan be regarded as separate species.An analysis of the morphological and physiological characteristics was performed.Ascospore formation was observed on acetate agar and Gorodkowa agar.The new Zygosaccharomyces species differed physiologically from Z.mellis in 4 assimilation tests.This data supports the hypothesis that the new species,Zygosaccharomyces siamensis,is a novel ascosporogenous yeast.The type strain is JCM 16825T(=CBS 12273T)and a description is given here.
