• 미생물학회지
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• 제5권1호
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• pp.1-6
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• 1967

The environmental effects on radio-sensitivities of Lactobacillus and Saccharomyces cerevisiae were studied; Liquid suspensions of Lactobacillus and yeast were gamma-irradiated under various conditions; temperatures, hydrogen ion concentrations, amino acids and vitamins were treated seperately with variations of concentrations. (shown in figures) It is found that simultaneous heat treatment is effective to sterilize microorganisms than pre after treatment, and concentration of hydrogen ion does not affect the lethalty of yeast but or Lactobacilli was affect at the range of pH. 5.0 to 7.0. Ascorbic acid, thiamin and pyridoxine were protective dependently against lethal action of gamma-ray and its protective effects increase with the increasings of concentrations. Glutamic acid, aspartic acid, tyrosine and phenylalanine were proved to be protective for both strains at 0.1 between 1.0 percent. It can be suggested that industrial sterilizing doses of irradiation by gamma-ray for food should be applied more than those dose of saline or buffer suspension, because natural food stuffs are rich of vitamins and amino acids.

• Journal of Microbiology
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• 제34권4호
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• pp.311-315
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• 1996

The retroviral Gag polyprotein directs the assembly of virion particles and plays an important role in some events after entry into a host cell. The Gag polyprotein of a virus mixture is responsible for inducing murine acquired immunodeficiency syndrome (MAIDS) when injected into susceptible strains of mice. In order to identify the host cellular proteins which interact with the MAIDS virus Gag proteins and possibly mediate the function of the Gag proteins, mouse T-cell leukemic cDNA expression library was screened using the yeast GAL4 two hybrid system. Of 11 individual positive clones, the clone Y1 was selected for the study of protein-protein interaction. Its DNA sequence revealed that it was an exact match to the murine SH3 domain-containing protein SH3P8. It is expressed as 2.4 kbp transcripts in testis at higher levels and in various tissues tested at lower levels. Glutathione S-transferase-Y1 fusion protein binds tightly to $Pr60^{def-gag}$ as well as $Pr65^{eco-gag}$.

• Natural Product Sciences
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• 제9권2호
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• pp.60-63
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• 2003

Effect of grape seed extract (GSE) against Candida albicans was examined under in-vitro and in-vivo conditions. The GSE was extracted in ethanol. In-vitro results from an agar diffusion susceptibility assay showed the GSE inhibited C. albicans growth. This anticandidal effect was at dose-dependency. In experiments with animals, mice that received the GSE (0.5 mg per mice), intravenously (i.v.), before i.v.-infection wish viable C. albicans yeast cells survived longer than diluent (buffer)-received control mice. In contrast, when GSE was given to mice after the mice were infected with the yeast cells, these mice showed a similar survival rate as compared to control mice that received no treatment with the GSE. Taken together, these data indicate that GSE has prophylactic effect but not therapeutic effect against disseminated candidiasis.

• 펄프종이기술
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• 제43권2호
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• pp.72-76
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• 2011

Antimicrobial activities of the Acidic Liquid originated from Carbonized Rice Hull(ALCRH) and the paper treated with ALCRH were investigated to apply ALCRH to functional paper products as a natural antimicrobial agent. ALCRH showed antimicrobial activity for bacteria and yeast, with higher performance for bacteria than for yeast. Antimicrobial activity was not developed on paper coated with ALCRH by bar coater probably due to the evaporation of antimicrobial compounds of ALCRH from the paper surface with time. Saturation of paper with ALCRH was essential to develop antimicrobial activity on the paper. Dipping paper in ALCRH solution was recommended as one of the effective ways to make antimicrobial paper.

• Asian-Australasian Journal of Animal Sciences
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• 제29권9호
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• pp.1273-1279
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• 2016

The objectives of this study were to determine an optimal cultivation time for populations of yeast and lactic acid bacteria (LAB) co-cultured in fermented milk and effects of soybean meal fermented milk (SBMFM) supplementation on rumen degradability in beef cattle using nylon bag technique. The study on an optimal cultivation time for yeast and LAB growth in fermented milk was determined at 0, 4, 8, 24, 48, 72, and 96 h post-cultivation. After fermenting for 4 days, an optimal cultivation time of yeast and LAB in fermented milk was selected and used for making the SBMFM product to study nylon bag technique. Two ruminal fistulated beef cattle ($410{\pm}10kg$) were used to study on the effect of SBMFM supplementation (0%, 3%, and 5% of total concentrate substrate) on rumen degradability using in situ method at incubation times of 0, 2, 4, 6, 12, 24, 48, and 72 h according to a Completely randomized design. The results revealed that the highest yeast and LAB population culture in fermented milk was found at 72 h-post cultivation. From in situ study, the soluble fractions at time zero (a), potential degradability (a+b) and effective degradability of dry matter (EDDM) linearly (p<0.01) increased with the increasing supplemental levels and the highest was in the 5% SBMFM supplemented group. However, there was no effect of SBMFM supplement on insoluble degradability fractions (b) and rate of degradation (c). In conclusion, the optimal fermented time for fermented milk with yeast and LAB was at 72 h-post cultivation and supplementation of SBMFM at 5% of total concentrate substrate could improve rumen degradability of beef cattle. However, further research on effect of SBMFM on rumen ecology and production performance in meat and milk should be conducted using in vivo both digestion and feeding trials.

• 미생물학회지
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• 제30권6호
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• pp.519-523
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• 1992

The glucoamylase of Candida tsuubaensis was purified to homogeneity form culture filtrate by means of ultrafiltration, Sephacryl S-200 gel filtration and Sp-Sephadex C-50 chromatography. The purified enzyme was a glycoprotein with a molecular mass of approximately 50 kDa, which was a monomeric protein. Km values were 5.8 mg/ml for soluble starch and 0.04 mM for maltose. Glucoamylase also released only glucose from both pullulan and isomaltose. The analysis of amino acid composition revealed that the enzyme contained a high content of acidic and polar amino acids. In addition, Western blotting analysis indicates that C. tsukubaensis glucoamylase is resistant to glucose repression.

• 미생물학회지
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• 제45권3호
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• pp.239-245
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• 2009

번역 개시 인자 eIF1A는 진핵생물에서 43S preinitiation complex 형성을 비롯한 번역 개시 과정의 여러 단계에서 필수적인 역할을 하며, 잘 보존된 oligonucleotide-binding (OB) fold를 가지고 있는 단백질이다. 본 연구진은 이전 연구에서 eIF1A가 RNA annealing 활성을 가지고 있으며 double-stranded RNA에 결합하여 안정된 복합체를 형성한다는 것을 발견한 바 있다. 본 연구에서는 이러한 활성을 나타내는데 필요한 active site를 찾고, 이러한 활성이 효모의 성장에 필수적인 기능인지를 알아보기 위하여 여러 가지 돌연변이를 제조하였다. N-말단과 C-말단은 제거되었지만 완전한 OB-fold를 가지고 있는 eIF1A($\Delta$T)는 RNA annealing 활성을 보이는 반면, OB-fold에 돌연변이가 도입된 단백질들은 모두 활성이 사라졌다. 또한, R57D 돌연변이를 제외한 모든 OB-fold 돌연변이는 dsRNA에도 결합하지 않았다. 이러한 결과는 eIF1A의 RNA annealing 활성과 dsRNA 결합에는 완전한 OB-fold domain이 필요하다는 것을 의미한다. 돌연변이들이 효모의 성장에 미치는 영향을 조사한 결과, RNA annealing 활성과 효모의 성장은 뚜렷한 연관성이 없었으며, 적어도 R57D와 K94D 경우에는 돌연변이가 성장하지 못하는 원인이 생체 내 eIF1A 단백질의 안정성과 관계있는 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제30권4호
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• pp.552-560
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• 2020

Human carbonic anhydrase (CA) isozyme II has been used as protein target for disorder treatment including glaucoma. Current clinically used sulfonamide-based CA inhibitors can induce side effects, and so alternatives are required. This study aimed to investigate a natural CA inhibitor from Murraya paniculata. The previously developed yeast-based assay was used to screen 14 compounds isolated from M. paniculata and identified by NMR analysis for anti-human CA isozyme II (hCAII) activity. Cytotoxicity of the compounds was also tested using the same yeast-based assay but in a different cultivation condition. Two flavonoid candidate compounds, 5, 6, 7, 8, 3', 4', 5'-heptamethoxyflavone (4) and 3, 5, 7, 8, 3', 4', 5'-heptamethoxyflavone (9), showed potent inhibitory activity against hCAII with a minimal effective concentration of 10.8 and 21.5 μM, respectively, while they both exhibited no cytotoxic effect, even at the highest concentration tested (170 μM). The results from an in vitro esterase assay of the two candidates confirmed their hCAII inhibitory activity with IC₅₀ values of 24.0 and 34.3 μM, respectively. To investigate the potential inhibition mechanism of compound 4, in silico molecular docking was performed using the FlexX and SwissDock software. This revealed that compound 4 coordinated with the Zn²⁺ ion in the hCAII active site through its methoxy oxygen at a distance of 1.60 Å (FlexX) or 2.29 Å (SwissDock). The interaction energy of compound 4 with hCAII was -13.36 kcal/mol. Thus, compound 4 is a potent novel flavonoid-based hCAII inhibitor and may be useful for further anti-CAII design and development.

• Journal of Microbiology and Biotechnology
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• 제25권3호
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• pp.358-365
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• 2015

ε-Poly-L-lysine (ε-PL) is a homopolymer of L-lysine molecules connected between the epsilon amino and alpha carboxyl groups. This polymer is currently used as a natural preservative in food. Insufficient biomass is a major problem in ε-PL fermentation. Here, to improve cell growth and ε-PL productivity, various nitrogen-rich nutrients were supplemented into flask cultures after 16 h cultivation, marking the onset of ε-PL biosynthesis. Yeast extract, soybean powder, corn powder, and beef extract significantly improved cell growth. In terms of ε-PL productivity, yeast extract at 0.5% (w/v) gave the maximum yield (2.24 g/l), 115.4% higher than the control (1.04 g/l), followed by soybean powder (1.86 g/l) at 1% (w/v) and corn powder (1.72 g/l) at 1% (w/v). However, supplementation with beef extract inhibited ε-PL production. The optimal time for supplementation for all nutrients examined was at 16 h cultivation. The kinetics of yeast-extract-supplemented cultures showed enhanced cell growth and production duration. Thus, the most commonly used two-stage pH control fed-batch fermentation method was modified by omitting the pH 5.0-controlled period, and coupling the procedure with nutrient feeding in the pH 3.9-controlled phase. Using this process, by continuously feeding 0.5 g/h of yeast extract, soybean powder, or corn powder into cultures in a 30 L fermenter, the final ε-PL titer reached 28.2 g/l, 23.7 g/l, and 21.4 g/l, respectively, 91.8%, 61.2%, and 45.6% higher than that of the control (14.7 g/l). This describes a promising option for the mass production of ε-PL.

• 한국식품조리과학회지
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• 제31권1호
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• pp.1-8
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• 2015

Organic acids are known as natural sanitizers. We examined the sanitizing effects of five organic acids (acetic acid, propionic acid, citric acid, malic acid, and lactic acid) and their persistence on three pectinolytic yeast strains isolated from decayed citrus, and the persistence of their sanitizing effects was determined during storage at $4^{\circ}C$ and $16^{\circ}C$. The 7~8 log CFU/mL of the mixed three yeast mixture was exposed to various concentrations of each organic acid for 1 min. The yeast mixtures decreased under detection limit(1 log CFU/mL) in 1% of acetic acid, followed by in 3% of propionic acid with the reduction of 5 log CFU/mL. The citric acid, malic acid, and lactic acid decreased the number of yeasts under detection limit at 7.5%. When treated with deionized water and 1~5% of organic acids were treated on the surfaces of citrus contaminated by yeasts, total numbers of the yeasts decreased under detection limit(3 log CFU) at 5% of acetic acid and 4 log CFU/piece at 5% propionic acid compared with deionized water. When treated with acetic acid and propionic acid on the stem ends of the contaminated citrus, total numbers of the yeasts significantly decreased 0.5 log CFU/piece at 3% of both organic acids. During storage at $4^{\circ}C$ and $16^{\circ}C$ for 20 days, total number of yeasts significantly decreased at 2% acetic acid compared with deionized water. This study suggested that organic acids could be used to sanitize microbial contaminants from citrus for storage and transportation.