• 한국식품영양과학회지
• /
• 제14권4호
• /
• pp.401-408
• /
• 1985

효모세포벽 용해효소의 일종인 Zymolyase$(endo-{\beta}-1\;,3-glucanase)$와 더불어 Arthrobacter luteus로 부터 생산되었고, 또한 Zymolyase의 조효소중에서 발견된 바 있는 염기성 AL-protease의 효모세포벽 용해작용을 S. sake의 생세포와 그 세포벽 표품(標品)을 사용하여 조사하였다. AL-protease의 효모 생세포에 대한 용해활성은 그 단독작용만으로는 지극히 미약하였으나, Zymolyase와의 복합작용에 의해서 용해활성은 고도로 상승하였다. 효모생세포를 AL-protease와 Zymolyase로써 단계적인 처리를 할 경우, 효모세포는 AL-protease로 전처리된 뒤에 Zymolyase로 처리되는 처리 순서에 한하여 효과적으로 용해되었다. 이러한 AL-protease의 촉진적 작용은 AL-protease처럼 염기성이고 serine protease로 알려진 몇가지 시판의 효소들 중에서는 발견되지 않았으며, 또한 AL-protease의 이러한 작용은 실험에 사용된 효모들의 배양조건 및 균종에 따라서 커다란 영향을 받는 것으로 밝혀졌다. AL-protease는 효모세포벽 표품(標品)으로부터 일정량의 peptide와 상당량의 당을 유리시키고 있으나, 그 세포벽을 66% 이상은 용해시키지 못하였다. 반면에, Zymolyase는 그 단독작용으로도 효모세포벽을 거의 완전히 용해시킬 수 있었다. 이상의 실험결과를 기초로 하여, S. sake 세포벽의 용해에 있어서 AL-protease의 효소적 작용은, 먼저 AL-protease가 mannan과 단백질로 구성되는 세포벽 표층부에 결합하고, 이어서 그들의 구조를 변화시킴으로써, Zymolyase를 세포벽의 외부로 부터 알카리 불용성 glucan으로 구축되고 있는 세포벽 내부의 골격구조로까지의 침투를 촉진시키는 것으로 추론되었다.

• Applied Biological Chemistry
• /
• 제49권1호
• /
• pp.55-59
• /
• 2006

본 연구는 게르마늄 강화 효모의 제조 공정을 위한 최적의 조건을 확인하고 제조된 게르마늄 강화 호모 내의 게르마늄 결합 상태 확인을 목적으로 수행하였다. 그 결과 영양소별 최적조건은 글루코스 3.0%, 효모추출물 0.3%, 펩톤 0.5%이었으며, 이 때 생성된 균체량은 67.4 mg/ml이었다. 또한 균체와 게르마늄 용액 혼합 비율은 1 : 0.5(50%), pH는 6.5 및 온도는 $35^{\circ}C$로 배양하는 조건이 높은 함량의 게르마늄을 효모 균체 내로 흡수시켜 게르마늄 강화 효모를 생산하는 것을 가능하게 하였다. 배양 과정을 통해 생산된 게르마늄 강화 효모는 배양 과정동안의 구조적 변화에 의해 효모 내에 흡수된 무기 형태인 $GeO_2$ 게르마늄과는 다른 구조를 나타내었다. 게르마늄 강화 효모는 효모 배양 과정을 통해 인체에 안전한 형태인 천연 유기 게르마늄을 형성하였다. 이는 각종 암, 성인병의 예방과 치료, 인체 면역력의 증진 등 건강 증진을 위한 새로운 기능성 원료로의 활용이 기대되며, 이에 대한 안전성 등의 지속적인 연구가 필요할 것으로 사료된다.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2003년도 생물공학의 동향(XII)
• /
• pp.467-470
• /
• 2003

The endoxylanase (642 bp; 213 amino acids) and ${\beta}-xylosidase$ (1,602 bp; 533 amino acids) genes from Bacillus sp. were amplified by PCR and separately inserted downstream of the yeast ADH1 promoters, resulting in the pAEDX-1 and pAEX plasmid. When the yeast transformants, S. cerevisiae SEY2102 harboring pAEDX-1 or pAEX, were grown on YPD medium, the total activities of the enzymes reached about 9.8 unit/mL for endoxylanase and 2.9 unit/mL for ${\beta}-xylosidase$. When the three kinds of xylan from oat spelts, birch wood, and corncob were hydrolyzed by treatment of recombinant endoxylanase and ${\beta}-xylosidase$, it was found that xylose, xylobiose and xylotriose were produced and xylose was the major product after 12 h reaction. In addition, with the higher amount of enzymes, the more amount of xylose was produced.

• Journal of Microbiology and Biotechnology
• /
• 제15권5호
• /
• pp.1146-1151
• /
• 2005

The yeast Candida albicans has a distinguishing feature, dimorphism, which is the ability to switch between two morphological forms: a budding yeast form and a multicellular invasive filamentous form. This ability has been postulated to contribute to the virulence of this organism. Previously, we reported that the yeast-to-hypha transition in this organism is suppressed by farnesoic acid, a morphogenic autoregulatory substance that accumulates in the medium as the cells proliferate. In this study, using a differential display reverse transcription polymerase chain reaction (DDRT-PCR) technique, we have identified several genes induced in C. albicans by farnesoic acid treatment. These observations indicate that farnesoic acid can alter the expressivity of multiple genes, including the DNA replication machinery and cell-cycle-control proteins.

• Journal of Microbiology and Biotechnology
• /
• 제17권7호
• /
• pp.1139-1146
• /
• 2007

Cultures of Saccharomyces cerevisiae were subjected to the effect of PEF (pulse electric field) and a source of selenium. The culture period after which yeast cells were subjected to PEF treatment was optimized, as was the duration of the exposure. Optimization of the nutrient medium composition in S. cerevisiae cultures resulted in an over 1.8-fold increase in selenium accumulation with relation to cultures on the initial substrate. Optimization of the pH value and of culture duration resulted in selenium accumulation increase by approximately 78%. A significant correlation was found between the accumulation of selenium in yeast cells and its concentration in the culture substrate. The highest accumulation of selenium in the biomass of yeast, approx. $240\;{\mu}g/g$ d.m., was obtained after 15-min exposure to PEF on a 20-h culture. An approx. 50% higher content of selenium in cells was recorded, as compared with the control culture without the application of PEF.

• 한국미생물·생명공학회지
• /
• 제48권4호
• /
• pp.423-428
• /
• 2020

In vitro evolution is a powerful technique for the engineering of yeast strains to study cellular mechanisms associated with evolutionary adaptation; strains with desirable traits for industrial processes can also be generated. There are two distinct approaches to generate evolved strains in vitro: the sequential transfer of cells in the stationary phase into fresh medium or the continuous growth of cells in a chemostat bioreactor via the constant supply of fresh medium. In culture, evolutionary forces drive diverse adaptive mechanisms within the cell to overcome environmental or intracellular stressors. Especially, this engineering strategy has expanded to the field of human cell lines; the understanding of such adaptive mechanisms provides promising targets for the treatment of human genetic diseases and cancer. Therefore, this technology has the potential to generate numerous industrial, medical, and academic applications.

• Genomics & Informatics
• /
• 제7권4호
• /
• pp.203-207
• /
• 2009

The target of rapamycin (TOR) signaling pathway conserved from yeast to human plays critical roles in regulation of eukaryotic cell growth. It has been shown that TOR pathway is involved in several cellular processes, including ribosome biogenesis, nutrient response, autophagy and aging. However, due to the functional diversity of TOR pathway, we do not know yet some key effectors of the pathway. To find unknown effectors of TOR signaling pathway, we took advantage of a green fluorescent protein (GFP)-tagged collection of budding yeast Saccharomyces cerevisiae. We analyzed protein abundance changes by measuring the GFP fluorescence intensity of 4156 GFP-tagged yeast strains under inhibition of TOR pathway. Our proteomic analysis argues that 83 proteins are decreased whereas 32 proteins are increased by treatment of rapamycin, a specific inhibitor of TOR complex 1 (TORC1). We found that, among the 115 proteins that show significant changes in protein abundance under rapamycin treatment, 37 proteins also show expression changes in the mRNA levels by more than 2-fold under the same condition. We suggest that the 115 proteins indentified in this study may be directly or indirectly involved in TOR signaling and can serve as candidates for further investigation of the effectors of TOR pathway.

• 미생물학회지
• /
• 제5권1호
• /
• pp.1-6
• /
• 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.

• Infection and chemotherapy
• /
• 제50권4호
• /
• pp.362-366
• /
• 2018

Millerozyma farinosa (formerly Pichia farinosa) is halotolerant yeast mainly found in food and ubiquitous in the environment. It was a rare yeast pathogen, but it has recently emerged as a cause of fungemia in immunocompromised patients. Optimal therapy for invasive fungal infection by this pathogen remains unclear. We report a case of catheter related blood stream infection caused by M. farinosa in a 71-year-old patient who recovered successfully after removal of the central venous catheter and treatment with micafungin.

• 한국미생물·생명공학회지
• /
• 제3권1호
• /
• pp.35-39
• /
• 1975

시판 정제 amylase 효소제를 이용하여 탁주양조때 탁주의 특징인 산미를 부여하기 위하여 유산균 Lactobacillus bulgaricus를 첨가하여 검토한 결양 1) L. bulgaricus의 생육 적온인 45$^{\circ}C$에서 8시간과 16시간 유산발효시킨 후에 효모를 첨가하여 만든 탁주류의 산도는 11.6과 13.9로서 너무 과양의 산이 생성되므로 탁간무로서는 불적당하었다. 2) 탁주류의 제조에서 유산난을 효모와 함께 3$0^{\circ}C$에서 접종하여 발효시킴으로서 산도8, 정도 12 vol%의 적당한 탁주류를 얻을 수 있었다. 3) 정제효소제와 유산균을 이용하여 탁주를 제조할때는 유산어과 효모의 동시접종에 앞서 당화효업의 작용최적온도에서 6시개동안정도 당화시킴이 합리적이다.