• 생명과학회지
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• 제13권5호
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• pp.712-717
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• 2003

박테리오신의 일종인 leucocin A를 생산하는 효모의 제작을 위하여 117 bp 길이의 개시코돈과 종지코돈을 포함하는 leucocin A 유전자를 합성하여 효모운반체인 pAUR123에 클로닝하였다. 형질전환된 효모는 부패균의 일종인 고초균(Bacillus subtilis)에 대해 항균활성을 나타냈다. 형질전환 효모로부터 분리한 플라스미드를 주형으로 하고 leucocin A에 특이적인 primer들을 이용하여 PCR 반응을 행한 결과, 효모에 도입된 leucocin A 유전자를 확인할 수 있었다. 이 연구의 결과로 부패하기 쉬운 식품들의 보존성을 향상시키거나, 내성이 생긴 병원균의 생육을 저해하기 위한 항생제로 사용할 수 있는 박테리오신을 산업적으로 생산할 수 있는 효모세포를 제작하였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권3호
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• pp.280-283
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• 2005

The adsorption of a model protein bovine serum albumin (BSA) in expanded bed chromatography was undertaken by exploiting a commercially available expanded bed column (20 mm i.d.) from UpFront Chromatography and Streamline DEAE $(\rho=1.2g/cm^3)$ from Amersham Pharmacia Biotechnology. The influence of whole yeast cells on the adsorption capacity of column was explored by employing yeast cells in a concentration ranged of 0 to $15\%(w/v)$. Equilibrium isotherms for adsorption of BSA on Streamline DEAE were correlated by using Langmuir equation. The presence of yeast cells resulted in decreased of BSA binding capacity in both batch binding and expanded bed chromatography. Results indicated that the yeast cells act as competitor for proteins to bind to the sites on adsorbents.

• Mycobiology
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• 제30권1호
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• pp.27-30
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• 2002

Two-hundred two yeast strains were isolated from rhizosphere(87 strains) and nonrhizosphere(115 strains) areas of potato, maize, vegetable marrow, and cabbage plants. On the basis of 26 morphological and physiological properties, the isolated yeast strains were assigned to 9 genera and 15 species. Trichosporon beigelii, Kluyveromyces marxianus and Torulaspora delbrueckii were the dominant species. Cryptococcus humicolus and Candida tropicalis were represented by considerable numbers of strains. Of low occurrence were Saccharomyces cerevisiae and Candida blankii. Other yeast species were represented by single or two strains. Total counts of yeast cells per gram dry soil ranged from $1.1{\times}10^3$ to $6.6{\times}10^3$ in soil samples of rhizosphere areas and from $6.5{\times}10^2$ to $5.6{\times}10^3$ in soil samples of nonrhizosphere areas. Types of the tested plants affected not only the total counts of yeast cells but also spectra of yeast species. Relationships of age of potato plant, moisture contests of soil samples, and its pH values and total counts of yeast cells were discussed.

• 한국식품영양학회지
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• 제1권1호
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• pp.3-6
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• 1988

For the purpose of the production of yeast cell protein from rice bran oil, it's assimillating yeast(E222) was isolating from soil and the resulting of identification was shown that it was belonging to Candida aibican species Total free amino acids from yeast cells were shown 0.05% per gram. Nine other species of amino acids as well as glycine, glutamic acid, alanine, leucine and aspartic acid were produced from yeast cells.

• 한국미생물·생명공학회지
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• 제25권5호
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• pp.512-519
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• 1997

RNA accumulating strain of Torulopsis versatilis MT-1 was cultured in molasses medium for higher contents of RNA in cell. Yeast cells were harvested at logarithmic phase on synchronous culture. Yield of cells on dry base to input sugar was 59.5%. Crude protein content was 55.1% in cell. RNA content was 13.9%. Some problems found in the process for the preparation of yeast extracts were improved by the addition of culture broth of Streptomyces faecalis MSF which secrete RNase (5' nuclease and 5' adenylic acid deaminase). When the culture broth of S. faecalis MSF was added in autolysis process 46% of RNA in cell was converted to I and G(5' inosinic acid and 5' guanylic acid) in extract. By addition of 3-7% culture broth of S.faecalis MSF in autolysis or enzymolysis process at the start or early stage, RNA in extract was converted easily to I and G and protein in cells was easily extracted and hydrolyzed to amino acid. Taste of those yeast extracts was delicious. The yeasty smell in yeast extracts was removed. And cell debris was easily removed from extract.

• Journal of Ginseng Research
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• 제10권2호
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• pp.200-208
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• 1986

It was attempted in this study to investigate the effect of ginseng saponin on several glycolytic enzymes of yeast cell and the following results were obtained. The amount of $CO_2$formed during the incubation of yeast cells in medium containing saponin fraction of Panax ginseng C.A. Meyer was greater than that of control cells and found that the $CO_2$ formation was greatest when the cells were grown in the medium containing 10$^{-3}$% of the saponin fraction, at which the uptake of inorganic phosphate and glucose consumption were also increased. Radioactivity study of several glycolytic intermediates of yeast cells cultured in the medium containing [U-$^{14}$C]-glucose showed that the radioactivity of fructose 6-phosphate of test cells was as much as 1.6times that of control group. On the other hand, the radioactivity of pyruvate of test cells was considerably decreased compared to control. Investigation of the effect of ginseng saponin on yeast hexokinase, phosphoglucose isomers, pyruvate kinase and perverted decarboxylase in vitro showed that the maximum activities of the above enzymes were observed when the concentration of ginseng saponin was 10-$^{-5}$% in the reaction mixture. It seemed that the ginseng saponin stimulated both glycolytic enzymes such as hexokinase, phosphoglucose isomers and perverted decarboxylase significantly.

• KSBB Journal
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• 제14권5호
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• pp.561-565
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• 1999

Optimum conditions for vacuum-drying ad cultivation of yeast cells for the production of active dry yeast were examined. At lower temperature, more drying time was required to dry the yeast pellet to reach the desirable water content(8%). Optimum temperature of vaccum oven and time for drying was 63$^{\circ}C$ and 90 min, respectively. Optimum medium composition for flask culture using cane molasses as the substrate were 0.25% sugar, 0.013% $K_2$HPO$_4$, 0.1% $K_2$HPO$_4$. and 0.125% (NH$_4$)$_2$SO$_4$. Culture temperature $25^{\circ}C$ gave the highest survival rate of dired yeast. After finishing fed-batch culture and the culture was left in the fermentor without adding any sugar or nutrient, survival of the dried yeast harvested from the fermentor increased to 86.0% after 36 hr. It was also observed that the yeast cells with higher budding rates showed lower survival rate.

• Journal of Plant Biology
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• 제7권3호
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• pp.1-8
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• 1964

Exposing yeast cells with a certain genotype to different inducers, the ability of the yeast cells (Saccharomyces cerevisiae) to obtain enhanced fermentation for carbohydrates was observed. Regardless of the preexposure to any substrate, the inherent character incapable of fermenting a certain carbohydrate was maintained, while utilization of carbohydrates by the cells with a certain gene markers was varied by the previous conditions where they were exposed. Galactose was the best inducer for the cells to elaborate melibiase, even the galactose was not utilized as a substrate. Preexposure to galactose seemed to be necessary for the cells to utilize galactose and melibiose. Galactose fermentation by GA cells was enhanced by the exposure of the cells to galactose, but not to melibiose, raffinose, sucrose or glucose. Delayed fermentation of sucrose by the cells exposed to glucose or melibiose, but not to galactose, was observed. Raffinose fermentation was obtained by the cells with either SU RAF or GA ME genes, but the enhanced fermentation of raffinose seemed to be dependent on which inducer the cells were exposed previously and enzymes induced by the inducer to break either one of the linkages of raffinose molecule, the alpha0galactosidic or the beta-fructo-furanosidic.

• Journal of Microbiology and Biotechnology
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• 제9권1호
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• pp.70-77
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• 1999

An extremely cadmium-tolerant budding yeast, Hansenula anomala B-7 underwent a morphological switch in response to either heat shock treatment or cadmium stress, respectively. It exhibited a morphological transition from a unicellular yeast form to a pseudohyphae-like coagulation when subjected to prolonged heat shock treatment. In contrast, the yeast cells showed an irregularity in surface morphology when given thermal stress for a short time. Patterns of proteins expressed in the pseudohyphae-like cells demonstrated that several proteins were overexpressed while others were underexpressed in comparison with those prepared from the cells in the yeast form. It was a striking feature, however, that nearly 40％ of the proteins extracted from the cells in the pseudohyphae form appeared to be composed of a single polypeptide. This polypeptide was apparently overexpressed during the pseudohyphae phase and its molecular weight was estimated to be 58 kDa according to SDS-PAGE analysis. However, a significant level of the protein was not observed in the cells before transition to pseudohyphae. The architecture of the cell shape was also damaged when incubated in a medium containing more than 1,000 ppm (8.9mM) of cadmium ions, although able to proliferate at a slow rate. However, the irregularity in the cell morphology exerted either by the brief heat shock treatment or by the cadmium stress with the high concentrations of the metal ions was not repaired, even though the damaged cells were allowed to grow for sufficient time in fresh, cadmium-free medium.

• Asian-Australasian Journal of Animal Sciences
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• 제26권6호
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• pp.856-863
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• 2013

An in vitro gas production technique was used in this study to elucidate the effect of two strains of active live yeast on methane ($CH_4$) production in the large intestinal content of pigs to provide an insight to whether active live yeast could suppress $CH_4$ production in the hindgut of pigs. Treatments used in this study include blank (no substrate and no live yeast cells), control (no live yeast cells) and yeast (YST) supplementation groups (supplemented with live yeast cells, YST1 or YST2). The yeast cultures contained $1.8{\times}10^{10}$ cells per g, which were added at the rates of 0.2 mg and 0.4 mg per ml of the fermented inoculum. Large intestinal contents were collected from 2 Duroc${\times}$Landrace${\times}$Yorkshire pigs, mixed with a phosphate buffer (1:2), and incubated anaerobically at $39^{\circ}C$ for 24 h using 500 mg substrate (dry matter (DM) basis). Total gas and $CH_4$ production decreased (p<0.05) with supplementation of yeast. The methane production reduction potential (MRP) was calculated by assuming net methane concentration for the control as 100%. The MRP of yeast 2 was more than 25%. Compared with the control group, in vitro DM digestibility (IVDMD) and total volatile fatty acids (VFA) concentration increased (p<0.05) in 0.4 mg/ml YST1 and 0.2 mg/ml YST2 supplementation groups. Proportion of propionate, butyrate and valerate increased (p<0.05), but that of acetate decreased (p<0.05), which led to a decreased (p<0.05) acetate: propionate (A: P) ratio in the both YST2 treatments and the 0.4 mg/ml YST 1 supplementation groups. Hydrogen recovery decreased (p<0.05) with yeast supplementation. Quantity of methanogenic archaea per milliliter of inoculum decreased (p<0.05) with yeast supplementation after 24 h of incubation. Our results suggest that live yeast cells suppressed in vitro $CH_4$ production when inoculated into the large intestinal contents of pigs and shifted the fermentation pattern to favor propionate production together with an increased population of acetogenic bacteria, both of which serve as a competitive pathway for the available H2 resulting in the reduction of methanogenic archaea.