• KSBB Journal
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• 제19권2호
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• pp.148-153
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• 2004

활성 효모의 동물사료 첨가제로의 이용성을 증진시키기 위하여 lipase 생산성이 높은 효모를 (주)강남유지로부터 채취한 폐유와 슬러지로부터 분리하였다. 분리된 균주를 이용, 자외선 돌연변이를 통해 lipase 생산성이 높은 균주를 개발하였으며 산업용 배양배지의 선별, 배양공정의 개선에 관한 연구를 수행하였다. 산업용 배지의 탄소원으로는 고과당, 질소원으로는 CSL이 각각 선정되었으며, 2%의 고과당, 1%의 CSL에서 배양조건을 최적화시키고자 하였다. 1%의 올리브유 첨가, 접종량 4%, 초기 pH 5, 그리고 배양온도 27$^{\circ}C$에서 lipase의 생산성이 최대가 됨을 확인할 수 있었으며 이 때 lipase 역가는 1.12 U/mL를 얻을 수 있었다.

• 미생물학회지
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• 제5권2호
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• pp.79-85
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• 1967

Kim, Jong Hyup., (Div. of Biology, Atomic Energy Research Institute,Korea.;) Studies on the Cellulor Metabolism in Microorganisms as influenced by Gamma-irradiation(III): On the Changes of Free Amino acid Pool and content of Protein in Yeast clls irradiated by .gamma.-ray. 1. The strain of Saccharomyces cerevisiae had been cultured synchronously in aerobic condition and irradiatel by gamma-ray from the source of cobalt-60. Drying in vacuum oven at $90^{\circ}C$ C over 12 hours, then changes of protein content (Kjeldahl) and free amino acid pool have been assayed with use of spectrophotometer. Results obtained were compared with those of unirradiated normal cells. 2. It is proved that amount of protein content in the irradiated cells increases to seven percent more than those of normal cells in the same weight of dried samples. It seems like carbohydrate breakown had been stimulated by irradiation and that relative contents of protein shows higher values than those of normal in the same weight of samples. 3. The amount of free amino acid pool in the irradiated cells shows less value about ten percent than those of normal cells, and rate of decreasing is also weak than those of standard reagent solution of amino acid. We may assume that free amino acid pool would be protected against radiation damage in living cells and more stable than in vitro. 4. The component of free amino acid pool have been assayed on second dimensional paper chromatogram, and the identified amino acids are as follows; aspartic acid, serine, glutamic acid, cystine, lysine, glycine, threonine, histidine, arginine, tyrosine, phenylalanine, valine and leucine. 5. Distributional presence of free amino acids are identical to that of normal cells except arginine, it is cosumable that radiation effect is univerlsal to all amino acid. However it is obvious that there are differences in radiolabilities of amino acids in irradiated cells.

• Applied Biological Chemistry
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• 제48권4호
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• pp.382-387
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• 2005

본 연구는 게르마늄 강화 효모의 제조 공정을 위한 최적의 조건을 잡고 제조된 게르마늄 강화 효모 내의 게르마늄의 결합 상태 확인을 목적으로 하였으며, 그 결과는 다음과 같다. 균체와 게르마늄 용액 혼합 비율 1 : 0.5(50%)로 하여 균체와 게르마늄 배양시 최적 조건인 pH 6.5, 온도 $35^{\circ}C$ 그리고 배양 시간은 20시간 배양하는 것이 높은 함량의 게르마늄을 효모 균체 내로 유입시켜 게르마늄 강화 효모를 생산하였으며, 이의 배양 과정을 통해 생산된 게르마늄 강화 효모는 배양 과정 동안의 구조적 변화에 의해 효모 내에 유입된 무기 형태인 $GeO_2$ 게르마늄과는 다른 구조를 형성하고 있었다. 또한 NMR 및 FTIR 실험을 실시한 결과 게르마늄 강화 효모의 발효 과정에 첨가한 무기 형태의 $GeO_2$가 배양 과정 동안 균체 내에서 게르마늄이 유입되는 과정에서 게르마늄이 단백질(혹은 펩타이드)과 결합하여 구조에 변화를 형성하였으며, 인공위액 안에서 투석막을 이용한 투석 전후에 따른 게르마늄 총량에서 투석 전후에 따른 차이가 나타나지 않았다. 따라서 게르마늄 강화 효모는 생합성 기법을 이용하여 게르마늄을 강화한 유기 게르마늄 생산방법으로 배양 과정을 통해 구조적으로 안전한 유기 게르마늄을 형성하여 인공위액 조건에서도 해리되지 않는 것으로 보여지며, 각종 암, 성인병의 예방과 치료, 인체 면역력의 증진 등 건강 증진을 위한 새로운 기능성 원료로의 활용이 기대되며, 이에 대한 지속적인 연구가 사료된다.

• 생명과학회지
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• 제14권1호
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• pp.26-31
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• 2004

본 연구는 redox regulator로 알려 진 Ref-1 (Redox factor-1)과 결합하는 새로운 단백질을protein-protein interaction의 원리를 이용한 방법인 yeast two-hybrid assay로 검색, 동정하고, 검색된 단백질의 in vitro, in vivo 기능을 규명하는 데 그 목적을 두고, mouse 11-day Embryo cNA library를 prey로, full length REF-1을 bait로 하여 yeast strain 인 HF7C에 cotransformatiom시킨 후 histidine, leucine, tryptophan이 결핍된 SD plate에서 키워 자란 yeast transformants를 $\beta$-galactosidaseassay하여 screening하여 분리한 세 개의 clone중 한 clone이 DNA sequencing으로 확인한 결과 mouse thioredoxin임을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제22권5호
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• pp.600-606
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• 2012

Studies into the cell death program termed apoptosis have resulted in new information regarding how cells control and execute their own demise, including insights into the mechanism by which death-preventing factors can inhibit Bax-induced caspase activation. We investigated high temperature stress-induced cell death in Brassica rapa. Using a yeast functional screening from a Brassica rapa cDNA library, the BH5-127 EST clone encoding an apoptotic suppressor peptide was identified. However, a phylogenic tree showed that BH5-127 clusters within a clade containing SUMO-1 (Small Ubiquitin-like Modifier-1). BH5-127 was confirmed similar to have function to SUMO-1 as Fas suppression. Expression of BH5-127 showed that substantial suppression of cell death survived on SD-galactose-$Leu^-$-$Ura^-$ medium. The results suggest that BrSE ($\underline{B}$rassica rapa $\underline{S}$entrin $\underline{E}$ST, BH5-127) is one of the important regulatory proteins in programming cell death, especially in the seedling stage of Chinese cabbage.

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

• BMB Reports
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• 제33권6호
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• pp.448-453
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• 2000

In yeast the key gluconeogenic enzyme, fructose-1,6-bisphosphatase (FBPase), is selectively targeted from the cytosol to the lysosome (vacuole) for degradation when glucose starved cells are replenished with glucose. The pathway for glucose induced FBPase degradation is unknown. To identify the receptor-mediated degradation pathway of FBPase, we investigated the presence of the FBPase receptor on the vacuolar membrane by cell fractionation experiments and binding assay using vid mutant (vacuolar import and degradation), which is defective in the glucose-induced degradation of FBPase. FBPase sedimented in the pellets from vid24-1 mutant after centrifugation at $15,000{\times}g$ for 15 min, suggesting that FBPase is associated with subcellular structures. Cell fractionation experiments revealed that FBPase is preferentially associated with the vacuole, but not with other organelles in vid24-1. FBPase enriched fractions that cofractionated with the vacuole were sensitive to proteinase K digestion, indicating that FBPase is peripherally associated with the vacuole. We developed an assay for the binding of FBPase to the vacuole. The assay revealed that FBPase bound to the vacuole with a Kd of $2.3{\times}10^6M$. The binding was saturable and specific. These results suggest that a receptor for FBPase degradation exists on the vacuolar membrane. It implies the existence of the receptor-mediated degradation pathway of FBPase by the lysosome.

• The Korean Journal of Physiology and Pharmacology
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• 제27권5호
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• pp.427-436
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• 2023

Mitotic arrest deficient 2 like 2 (Mad2L2, also known as Mad2B), the human homologue of the yeast Rev7 protein, is a regulatory subunit of DNA polymerase ζ that shares high sequence homology with Mad2, the mitotic checkpoint protein. Previously, we demonstrated the involvement of Mad2B in the cisplatin-induced DNA damage response. In this study, we extend our findings to show that Mad2B is recruited to sites of DNA damage in human cancer cells in response to cisplatin treatment. We found that in undamaged cells, Mad2B exists in a complex with Polζ-Rev1 and the APC/C subunit Cdc27. Following cisplatin-induced DNA damage, we observed an increase in the recruitment of Mad2B and Cdc20 (the activators of the APC/C), to the complex. The involvement of Mad2B-Cdc20-APC/C during DNA damage has not been reported before and suggests that the APC/C is activated following cisplatin-induced DNA damage. Using an in vitro ubiquitination assay, our data confirmed Mad2B-dependent activation of APC/C in cisplatin-treated cells. Mad2B may act as an accelerator for APC/C activation during DNA damage response. Our data strongly suggest a role for Mad2B-APC/C-Cdc20 in the ubiquitination of proteins involved in the DNA damage response.

• BMB Reports
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• 제39권6호
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• pp.709-716
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• 2006

Mammalian polo-like kinase 1 (Plk1) acts at various stages in early and late mitosis. Plk1 localizes at the centrosome and maintains this position through mitosis. Thereafter Plk1 moves to the kinetochore and midbody region, important sites during chromosome separation and cytokinesis. The catalytic domain of Plk1 is in the N-terminus region, whereas the non-catalytic region in the C-terminus of Plk1 has a conserved motif, named the Polobox. This motif is critical for Plk localization. EGFP proteins fused with the N-terminus and C-terminus of Plk1 localize in the nucleus and centrosomes, respectively. The core sequences of the polo-box (50 amino acids) also localize in Plk1 target organelles. To screen for domain-specific target proteins of Plk1, we constructed an N-terminal domain and a tandem repeat polo-box motif, and used them as templates in a yeast two-hybrid screen. The HeLa cell cDNA library indicated several proteins including the centrosome/kinetochore components or regulators, to be characterized as positive clones. Through in vitro protein binding analyses, we confirmed an interaction between these proteins and Plk1. The data reported from this study indicate that the N- and C- termini of Plk1 may function through recruitment and/or activation of domain-specific target proteins in dividing cells. Additionally, tandem repeats of the conserved core motif of the polo-box are sufficient for targeting and may be useful as a centrosome/kinetochore-specific targeting peptide.

• Journal of Dairy Science and Biotechnology
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• 제36권3호
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• pp.178-185
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• 2018

Kefir, which originates in the Caucasian mountains, is a cultured milk beverage produced by a combination of acidic and alcoholic fermentation. Kefir products are commonly used as food vehicles to deliver health-promoting materials including kefran and lactic acid bacteria to consumers. The aim of this study was to develop a freeze-dried starter culture without yeast and assess the suitability of kefir-like dairy products for the growth of lactic acid bacteria and the acidification of milk. Pasteurized whole milk (SNF 8.5%) stored at $25^{\circ}C$ was aseptically inoculated with starter cultures (0.002% w/v); it was kept at $25^{\circ}C$ until the pH attained a value of 4.6. Ten grams of the kefir-like product sample was diluted with 90 mL of 0.15% peptone water diluent in a milk dilution bottle, followed by uniform mixing for 1 min. Viable cells of Lactobacillus species were enumerated on modified-MRS agar (pH 5.2), with incubation at $37^{\circ}C$ for 48 h. Viable cells of Lactococcus species were enumerated on M17-lactose agar, with incubation at $32^{\circ}C$ for 48 h. The pH attained a value of 4.6 after fermentation for 9 h 30 min (Starter 1), 9 h 45 min (Starter 2), and 12 h (Starter 3). The viable cell count of Lactobacillus sp. and Lactococcus sp. was initially $10^5{\sim}10^6CFU/g$; it increased significantly to $10^9CFU/g$ after 12 h of incubation. During the storage of the kefir-like products at $4^{\circ}C$ for 1 4 days, the total viable cell numbers were unchanged, but the pH decreased slightly. The consistency of the kefir products increased gradually during the storage. The organoleptic properties of the kefir products fermented using the new starter culture are more desirable than those of commercial kefir. These results suggest that the newly developed starter culture without yeast could be suitable for kefir fermentation.