• 생명과학회지
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• 제11권1호
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• pp.19-23
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• 2001

To develop the effective microbial screening method, pyrolysis mass spectrometry (PyMS) fingerprinting was evaluated as a tool that discriminate various yeast strains. The target yeast strains were isolated from industrial wastewater. Seventeen environmental isolated yeast strains were examined by pyrolysis mass spectrometry and sequencing analysis of the large subunit rRNA gene D1/D2 region. The PyMS results were compared with those of sequencing analysis. Taxonomic correlations were observed between the PyMS data and the sequencing results. It was concluded that PyMS provides a rapid, reliable and cost-reducing method for discrimination of the yeast strains.

• Natural Product Sciences
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• 제9권4호
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• pp.299-303
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• 2003

For the screening of inhibitors of sterol biosynthesis from natural products, a simple and rapid assay method was developed using recombinant yeast carrying human lanosterol synthase, main target of this assay method. Sterol biosynthesis inhibition activity was monitored only by the inhibition of growth of the recombinant yeast. By changing the substrate, this assay method can figure out which step is inhibited in the sterol biosynthesis by the test material. With this assay method total 102 plant samples were screened for their inhibitory activity of sterol biosynthesis. Among plant water extracts screened, 11 plant samples showed inhibitory activity on sterol biosynthesis in ergosterol (-) medium. For selection of the specific inhibitory materials, 11 plant samples were reassayed in ergosterol (+) medium. After all 5 plant samples, Abutilon avicennae Gaertn. (stem), Alnus japonica Steud. (stem), Amaranthus mangostanus L. (aerial part), Philadelphus schrenckii Pupr. (leaf) and Pimpinelia brachycarpa Nakai (aerial part), showed specific inhibitory activity.

• Journal of Microbiology and Biotechnology
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• 제24권3호
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• pp.408-420
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• 2014

Yeast surface-displayed antibody libraries provide an efficient and quantitative screening resource for given antigens, but suffer from typically modest library sizes owing to low yeast transformation efficiency. Yeast mating is an attractive method for overcoming the limit of yeast transformation to construct a large, combinatorial antibody library, but the optimal conditions have not been reported. Here, we report a large synthetic human Fab (antigen binding fragment) yeast surface-displayed library generated by stepwise optimization of yeast mating conditions. We first constructed HC (heavy chain) and LC (light chain) libraries, where all of the six CDRs (complementarity-determining regions) of the variable domains were diversified mimicking the human germline antibody repertoires by degenerate codons, onto single frameworks of VH3-23 and $V{\kappa}1$-16 germline sequences, in two haploid cells of opposite mating types. Yeast mating conditions were optimized in the order of cell density, media pH, and cell growth phase, yielding a mating efficiency of ~58% between the two haploid cells carrying HC and LC libraries. We constructed two combinatorial Fab libraries with CDR-H3 of 9 or 11 residues in length with colony diversities of more than $10^9$ by one round of yeast mating between the two haploid HC and LC libraries, with modest diversity sizes of ${\sim}10^7$. The synthetic human Fab yeast-displayed libraries exhibited relative amino acid compositions in each position of the six CDRs that were very similar to those of the designed repertoires, suggesting that they are a promising source for human Fab antibody screening.

• Journal of Microbiology and Biotechnology
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• 제25권4호
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• pp.547-553
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• 2015

The yeast surface-displayed cDNA library has been used to identify unknown antigens. However, when unknown target antigens show moderate-to-low abundance, some modifications are needed in the screening process. In this study, a directional random-primed cDNA library was used to increase the number of candidates for the unknown antigen. To avoid the loss of target yeast clones that express proteins at a low frequency in the cDNA library, a comprehensive monitoring system based on magnetic-activated cell sorting, fluorescence-activated cell sorting, and immunofluorescence was established, and a small number of target yeast cells was successfully enriched. These results showed that our optimized method has potential application for identifying rare unknown antigens of the human monoclonal antibody.

• 한국환경농학회지
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• 제32권3호
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• pp.240-243
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• 2013

효모의 유용 기능을 탐색하기 위해서는 효모만을 스크리닝 하는 방법의 정립이 요구되는데 이를 위해서 알로에에 정착하는 효모 군집을 분석하였다. 본 연구에서는 알로에 베라(Aloe vera)와 알로에 사포나리아 (Aloe saponaria)의 잎을 파쇄하여 세균을 억제하기 위해서 항생제 chloramphenicol과 streptomycin과 곰팡이 생장을 억제하기 위해서 Triton X-100과 L-sorbose를 포함한 4가지 선택 배지(DOB with CS, GPY, YM, SCG)에 도말 하였고, A. vera에서 총 67균주, A. saponaria에서 총 42균주를 분리해 내었다. 분리된 균주를 ITS 1, 4 primer를 사용하여 sequence의 계통분석을 실시한 결과, A. vera에서는 Meyerozyma 가 56균주, Rhodotorula 가 1균주, Sporobolomyces 가 1균주, Cryptococcus 가 9균주, A. saponaria에서는 Rhodosporidium 가 41균주, Sporobolomyces가 1균주로 분포 되었다. 계통분석한 모든 분리 균주가 효모로 밝혀졌으며, 특히 대형 플레이트를 도입하여 신속하고 간편하게 대량의 효모를 발굴할 수 있음을 보였다.

• Mycobiology
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• 제46권1호
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• pp.33-46
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• 2018

Gray mold (Botrytis cinerea) is one of the most common diseases of strawberries (Fragaria${\times}$ananassa Duchesne) worldwide. Although many chemical fungicides are used for controlling the growth of B. cinerea, the risk of the fungus developing chemical resistance together with consumer demand for reducing the use of chemical fungicides have necessitated an alternative method to control this pathogen. Various naturally occurring microbes aggressively attack plant pathogens and benefit plants by suppressing diseases; these microbes are referred to as biocontrol agents. However, screening of potent biocontrol agents is essential for their further development and commercialization. In this study, 24 strains of yeast with antagonistic ability against gray mold were isolated, and the antifungal activity of the volatile and diffusible metabolites was evaluated. Putative mechanisms of action associated with the biocontrol capacity of yeast strains against B. cinerea were studied through in vitro and in vivo assays. The volatile organic compounds produced by the Galactomyces candidum JYC1146 could be useful in the biological control of plant pathogens and therefore are potential alternative fungicides with low environmental impact.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1985년도 워크샵 및 심포지엄 북한산국립공원의 식생
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• pp.73-81
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• 1985

We have previously isolated OsMADS4 gene that is a member of the class B MADS box genes from rice. In this study, another member of the class B MADS box genes was isolated from rice flower by the yeast two-hybrid screening method using OsMADS4 as bait. RNA blot analyses revealed that the clone, OsMADS16, was expressed in the second and third whorls, whereas the OsMADS4 transcripts were present in the second, third, and fourth whorls. These expression patterns of the OsMADS16 and OsMADS4 genes are very similar with those of AP3 and PI, the class B genes of Arabidopsis, respectively. In the yeast two-hybrid system, OsMADS4 interacted only with OsMADS16 among several rice MADS genes investigated, suggesting that OsMADS4 and OsMADS16 function as a heterodimer in specifying sepal and petal identities. We have also isolated OsMADS6 gene using OsMADS1 as a probe. Both are members of the AGL2 MADS family. Various MADS genes that encode for protein-protein interaction partners of the OsMADS6 protein were isolated by the yeast two-hybrid screening method. A majority of these genes belong to the AGL2 family. Sequence Homology, expression pattern, and ectopic expression phenotypes indicated that one of the interaction partners, OsMADS14, appears to be homologous to API, the class A MADS gene of Arabidopsis.

• Animal cells and systems
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• 제7권2호
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• pp.133-137
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• 2003

Secreted proteins and membrane proteins play key roles in the formation, differentiation, and maintenance of multicellular organisms. In this study, we undertook to characterize these protein types in the central nervous system of the marine snail Aplysia kurodai using a yeast-based signal sequence trap method. One hundred and three cDNA clones were obtained by screening 300,000 clones from the signal sequence trap cDNA library. Of these, twelve were identical to previously identified Aplysia genes, 19 were related to known proteins in other organisms, and 54 clones were novel. These 54 new genes had high signal peptide scores or were found likely to contain a transmembrane domain sequence. Only 18 of the 103 clones proved to be false positive. The study demonstrates that the signal sequence trap method is an effective tool for Isolating Aplysia genes encoding secreted and membrane proteins.

• 응용통계연구
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• 제24권6호
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• pp.1077-1094
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• 2011

마이크로어레이 유전자 발현 데이터인 yeast cdc15에 대해 시계열 데이터의 특성을 반영한 푸리에 계수를 이용한 검정통계량과 FDR 다중비교법을 이용하여 차별화된 유전자를 선별한 후 선별된 유전자들에 대해 모형기반 군집방법, K-평균법, PAM, SOM, 계층적 Ward 군집방법과 Fuzzy 군집방법을 실시하였다. 군집방법에 따른 특성을 알아보고 군집화 결과와 내부유효성 측도로 연결성 측도, Dunn 지수와 실루엣 값을 살펴본다. 또한 GO분석을 통한 생물학적 의미도 파악해본다.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1999년도 제13회 식물생명공학심포지움 New Approaches to Understand Gene Function in Plants and Application to Plant Biotechnology
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• pp.21-35
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• 1999

We have previously isolated OsMADS4 gene that is a member of the class B MADS box genes from rice. In this study, another member of the class B MADS box genes was isolated from rice flower by the yeast two-hybrid screening method using OsMADS4 as bait. RNA blot analyses revealed that the clone, OsMADS16, was expressed in the second and third whorls, whereas the OsMADS4 transcripts were present in the second, third, and fourth whorls. These expression patterns of the OsMADS16 and OsMADS4 genes are very similar with those of AP3 and PI, the class B genes of Arabidopsis, respectively. In the yeast two-hybrid system, OsMADS4 interacted only with OsMADS16 among several rice MADS genes investigated, suggesting that OsMADS4 and OsMADS16 function as a heterodimer in specifying sepal and petal identities. We have also isolated OsMADS6 gene using OsMADS1 as a probe. Both are members of the AGL2 MADS family. Various MADS genes that encode for protein-protein interaction partners of the OsMADS6 protein were isolated by the yeast two-hybrid screening method. A majority of these genes belong to the AGL2 family. Sequence Homology, expression pattern, and ectopic expression phenotypes indicated that one of the interaction partners, OsMADS14, appears to be homologous to API, the class A MADS gene of Arabidopsis.