• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.210-216
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• 2021

This study aimed to enhance ethanol productivity of Saccharomyces cerevisiae through genome editing using CRISPR/CAS9. To increase ethanol productivity, ACC1, ELO1, and OLE1 were overexpressed in S. cerevisiae using the CRISPR/CAS9 system. The strains overexpressing ACC1, ELO1, and OLE1 survived up to 24 h in YPD medium supplemented with 18% ethanol. Moreover, the ethanol yields in strains overexpressing ACC1 (428.18 mg ethanol/g glucose), ELO1 (416.15 mg ethanol/g glucose), and OLE1 (430.55 mg ethanol/g glucose) were higher than those in the control strains (400.26 mg ethanol/g glucose). In conclusion, the overexpression of these genes increased the viability of S. cerevisiae at high ethanol concentrations and the ethanol productivity without suppressing glucose consumption.

• The Korean Journal of Food And Nutrition
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• v.13 no.2
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• pp.158-163
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• 2000

Killer yeast, Hansenular capsulata S-13 were treated with heat, ethylmethane sulfonate and N-methyl-n'-nitro-n-nitrosoguanidine and a mutant(S13-E1), showing 2-fold higher killer toxin activity than that of parent strain to killer sensitive strain, Saccharomyces cerevisiae ATCC 38026 was obtained. Hansenular capsulata S13-E1 showed strong killer toxin activity to Saccharmyces mellis and Saccharomyces sal년 and four strains of gas-producing yeasts from traditional Doenjang and Kochujang. The culture condition for killer toxin production by Hansenular capsulata S13-E1 was optimized to be 1.0% potato extract, each 0.5% of peptone and glucose, and 0.025% MgSO4 with initial pH 4.5 at 3$0^{\circ}C$ and 36 hr of batch cultivation.

• Journal of Microbiology
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• v.44 no.6
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• pp.641-648
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• 2006

We previously reported that Skp1, a component of the Skp1-Cullin-F-box protein (SCF) complex essential for the timely degradation of cell cycle proteins by ubiquitination, physically interacts with Bfa1, which is a key negative regulator of the mitotic exit network (MEN) in response to diverse checkpoint-activating stresses in budding yeast. In this study, we initially investigated whether the interaction of Skp1 and Bfa1 is involved in the regulation of the Bfa1 protein level during the cell cycle, especially by mediating its degradation. However, the profile of the Bfa1 protein did not change during the cell cycle in skp1-11, which is a SKP1 mutant allele in which the function of Skp1 as a part of SCF is completely impaired, thus indicating that Skp1 does not affect the degradation of Bfa1. On the other hand, we found that the skp1-12 mutant allele, previously reported to block G2-M transition, showed defects in mitotic exit and cytokinesis. The skp1-12 mutant allele also revealed a specific genetic interaction with ${\Delta}bfa1$. Bfa1 interacted with Skp1 via its 184 C-terminal residues (Bfa1-D8) that are responsible for its function in mitotic exit. In addition, the interaction between Bfa1 and the Skp1-12 mutant protein was stronger than that of Bfa1 and the wild type Skp1. We suggest a novel function of Skp1 in mitotic exit and cytokinesis, independent of its function as a part of the SCF complex. The interaction of Skp1 and Bfa1 may contribute to the function of Skp1 in the mitotic exit.

• Molecules and Cells
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• v.28 no.6
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• pp.575-581
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• 2009

Ornithine decarboxylase (ODC) is a rate-limiting enzyme in the biosynthesis of polyamines, which are essential for cell growth, differentiation, and proliferation. This report presents the characterization of an ODC-encoding cDNA (SlitODC) isolated from a moth species, the tobacco cutworm, Spodoptera litura (Lepidoptera); its expression in a polyamine-deficient strain of yeast, S. cerevisiae; and the recovery in polyamine levels and proliferation rate with the introduction of the insect enzyme. SlitODC encodes 448 amino acid residues, 4 amino acids longer than B. mori ODC that has 71% identity, and has a longer C-terminus, consistent with B. mori ODC, than the reported dipteran enzymes. The null mutant yeast strain in the ODC gene, SPE1, showed remarkably depleted polyamine levels; in putrescine, spermidine, and spermine, the levels were > 7, > 1, and > 4%, respectively, of the levels in the wild-type strain. This consequently caused a significant arrest in cell proliferation of > 4% of the wild-type strain in polyamine-free media. The transformed strain, with the substituted SlitODC for the deleted endogenous ODC, grew and proliferated rapidly at even a higher rate than the wild-type strain. Furthermore, its polyamine content was significantly higher than even that in the wild-type strain as well as the spe1-null mutant, particularly with a very continuously enhanced putrescine level, reflecting no inhibition mechanism operating in the putrescine synthesis step by any corresponding insect ODC antizymes to SlitODC in this yeast system.

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.149-152
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• 2006

The sp%pl null mutant was constructed to study the function of fission yeast Schizosaccharomyces pombe spThp1, which is homologous to budding yeast Saccharomyces cerevisiae THP1. Tetrad analysis showed that the spThp1 is not essential for vegetative growth. The spThp1 null mutant also showed no massive poly(A)+ RNA export defect. However, spThp1 null is genetically associated with spMex67 null. These results suggest that spThp1 is involved in mRNA export out of the nucleus.

• Microbiology and Biotechnology Letters
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• v.13 no.2
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• pp.129-135
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• 1985

The amylolytic yeasts were isolated from natural sources. Among them, a strain FRI YO-32 was selected as one of the genetically potential microorganisms and was identified as a strain of Hansenula anomala var anomala. Genetic markers were introduced into the isolated haploid strains of the strain FRI YO-32 and Saccharomyces cerevisiae by conventional mutagenic procedures with EMS or MNNG.

• BMB Reports
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• v.34 no.5
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• pp.428-433
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• 2001

A defect in uvsC of Aspergillus nidulans caused high methyl methansulfonate (MMS)-sensitivity, hyporecombination, and a lack of UV induced mutation. The uvsC gene of Aspergillus nidulans shares a sequence similarity with the RAD51 gene of Saccharomyces cerevisiae. In this study, in vitro and in vivo tests were conducted in order to determine whether or not the UVSC protein had functional similarities to RAD51, the recombination enzyme in yeast. The purified recombinant UVSC protein, following expression in Escherichia coli, showed binding activity to single-stranded DNA (ssDNA), when both ATP and magnesium are present. In addition, ATPase activity was also demonstrated and its activity was stimulated in the presence of ssDNA. The UVSC protein that was expressed under the ADH promoter in S. cerevisiae suppressed in part the sensitivity to MMS of the rad51 null mutant. Similarly, when the uvsC cDNA was expressed from the nmt promoter, the MMS sensitivity of the rhp51 null mutant of Schizosaccharomyces pombe was partially complemented. These results indicate that the A. nidulans UVSC protein is a functional homologue of the RAD51 protein.

• BMB Reports
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• v.43 no.9
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• pp.622-628
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• 2010

Dimethyl sulfoxide (DMSO) can be reduced to dimethyl sulfide by MsrA, which stereospecifically catalyzes the reduction of methionine-S-sulfoxide to methionine. Our previous study showed that DMSO can competitively inhibit methionine sulfoxide reduction ability of yeast and mammalian MsrA in both in vitro and in vivo, and also act as a non-competitive inhibitor for mammalian MsrB2, specific for the reduction of methionine-R-sulfoxide, with lower inhibition effects. The present study investigated the effects of DMSO on the physiological antioxidant functions of methionine sulfoxide reductases. DMSO elevated hydrogen peroxide-mediated Saccharomyces cerevisiae cell death, whereas it protected human SK-Hep1 cells against oxidative stress. DMSO reduced the protein-carbonyl content in yeast cells in normal conditions, but markedly increased protein-carbonyl accumulation under oxidative stress. Using Msr deletion mutant yeast cells, we demonstrated the DMSO's selective inhibition of the antioxidant function of MsrA in S. cerevisiae, resulting in an increase in oxidative stress-induced cytotoxicity.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.196-200
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• 1999

A recombinant human $\alpha_{s1}$-casein was expressed as a secretory product in the yeast Saccharomyces cerevisiae. Three different leader sequences derived from the mating factor $\alpha$l (MF$\alpha$l), inulinase, and human $\alpha_{s1}$-casein were used to direct the secretion of human $\alpha_{s1}$-casein into the extracellular medium. Among the three leader sequences tested, the native leader sequence of human $\alpha_{s1}$-casein was found to be the most efficient in the secretory expression of human $\alpha_{s1}$-casein, which implies that the native leader sequence of human $\alpha_{s1}$-casein might be used very efficiently for the secretory production of other heterologous proteins in yeast. The recombinant human $\alpha_{s1}$-casein was proteolytically cleaved as the culture proceeded. Therefore, an attempt was made to produce human $\alpha_{s1}$-casein using a S. cerevisiae mutant in which the YAP3 gene encoding yeast aspartic protease 3 (YAP3) was disrupted. After 72 h of culture, most of the human $\alpha_{s1}$-casein secreted by the wild type was cleaved, whereas more than 70% of the human $\alpha_{s1}$-casein secreted by yap3-disruptant remained intact. The results suggest that YAP3 might be involved in the internal cleavage of human $\alpha_{s1}$-casein expressed in yeast

• Journal of Applied Biological Chemistry
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• v.54 no.1
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• pp.41-46
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• 2011

A galactose-fermenting yeasts, Saccharomyces cerevisiae No. 9, was selected by screening their abilities to produce carbon dioxide gas when grown on galactose. The selected strain, No. 9 and the reference strains NRRL Y-1528 which was exceptionally resistant to high concentration of substrate, were acclimated on sugars such as glucose, mannose, and galactose, and then their ethanol productivities were investigated during fermentation on these three carbon sources. Ethanol productivity of the strain No. 9 reached to the maximum levels after 18 h of fermentation and the ethanol yield was from 36 to 38% when presented as $[EtOH]_{max}/[Sugar]_{ini}(g/g)$, regardless of the conditions of acclimation. From the results obtained by acclimation and fermentation, it was concluded that the ethanol yields from galactose were not affected by the sugars acclimated. Improvements of the strain S. cerevisiae No. 9 were attempted to increase the fermentation efficiency and/or ethanol yields on high concentration of substrate by the conventional mutation methods employing methanesulfonic acid, ethyl ester (EMS). Mutants, Mut-5 (SJ1-40), -17 (LK4-25) and -24 (LK2-48) fermented galactose at the concentration of 20% in the levels of higher 39.9~51.6% than the mother strain, No. 9, however, their ethanol yields never exceeded those of the reference strain.