Developmental and environmental regulation of soybean SE60 gene expression during embryogenesis and germination

Choi, Yeonhee,Jeong, Cheol Woong,Ohr, Hyonhwa,Song, Sang-Kee,Choi, Yang Do,Lee, Jong Seob Springer-Verlag 2009 Planta Vol.230 No.5

Optimized Methods for the Isolation of Arabidopsis Female Central Cells and Their Nuclei

Yeonhee Choi,Kyunghyuk Park,Jennifer M. Frost,Adam James Adair,Dong Min Kim,Hyein Yun,Janie S. Brooks,Robert L. Fischer 한국분자세포생물학회 2016 Molecules and cells Vol.39 No.10

The Arabidopsis female gametophyte contains seven cells with eight haploid nuclei buried within layers of sporophytic tissue. Following double fertilization, the egg and central cells of the gametophyte develop into the embryo and endosperm of the seed, respectively. The epigenetic status of the central cell has long presented an enigma due both to its inaccessibility, and the fascinating epigenome of the endosperm, thought to have been inherited from the central cell following activity of the DEMETER demethylase enzyme, prior to fertilization. Here, we present for the first time, a method to isolate pure populations of Arabidopsis central cell nuclei. Utilizing a protocol designed to isolate leaf mesophyll protoplasts, we systematically optimized each step in order to efficiently separate central cells from the female gametophyte. We use initial manual pistil dis-section followed by the derivation of central cell proto-plasts, during which process the central cell emerges from the micropylar pole of the embryo sac. Then, we use a modified version of the Isolation of Nuclei TAgged in specific Cell Types (INTACT) protocol to purify central cell nuclei, resulting in a purity of 75-90% and a yield sufficient to undertake downstream molecular analyses. We find that the process is highly dependent on the health of the original plant tissue used, and the efficiency of protoplasting solution infiltration into the gametophyte. By isolating pure central cell populations, we have enabled elucidation of the physiology of this rare cell type, which in the future will provide novel insights into Arabidopsis reproduction.

Perpendicular Orientation of Diblock Copolymers Induced by Confinement between Graphene Oxide Sheets

Choi, Ki-In,Kim, Tae-Ho,Lee, Yeonhee,Kim, Hyeri,Lee, Hoyeon,Yuan, Guangcui,Satija, Sushil K.,Choi, Jae-Hak,Ahn, Hyungju,Koo, Jaseung American Chemical Society 2018 Langmuir Vol.34 No.4

<P>We have studied an orientation structure of self-assembled block copolymers (dPS-<I>b</I>-PMMA) of deuterated polystyrene (dPS) and poly(methyl methacrylate) (PMMA) confined between graphene oxide (GO) surfaces. The results of combination techniques, such as neutron reflectivity, time-of-flight secondary-ion mass spectrometry, grazing-incidence small-angle X-ray scattering, and scanning electron microscopy, show that self-assembled domains of the block copolymers in thin films near the GO sheets are oriented perpendicular to the surface of the GO monolayers, in contrast to the horizontal lamellar structure of the copolymer thin film in the absence of the GO monolayers. This is due to the amphiphilic nature of the GO, which leads to a nonpreferential interaction of both dPS and PMMA blocks. Double-sided confinement with the GO monolayers further extends the ordering behavior of the dPS-<I>b</I>-PMMA thin films. Continuous vertical orientation of the block copolymer thin films is also obtained in the presence of alternating GO layers within thick copolymer films.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2018/langd5.2018.34.issue-4/acs.langmuir.7b03991/production/images/medium/la-2017-03991k_0011.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la7b03991'>ACS Electronic Supporting Info</A></P>

Resetting and regulation of <i>FLOWERING LOCUS C</i> expression during Arabidopsis reproductive development

Choi, Jean,Hyun, Youbong,Kang, Min-Jeong,In Yun, Hye,Yun, Jae-Young,Lister, Clare,Dean, Caroline,Amasino, Richard M.,Noh, Bosl,Noh, Yoo-Sun,Choi, Yeonhee Blackwell Publishing Ltd 2009 The Plant journal Vol.57 No.5

<P>Summary</P><P>The epigenetic regulation of the floral repressor <I>FLOWERING LOCUS C</I> (<I>FLC</I>) is one of the critical factors that determine flowering time in <I>Arabidopsis thaliana</I>. Although many <I>FLC</I> regulators, and their effects on <I>FLC</I> chromatin, have been extensively studied, the epigenetic resetting of <I>FLC</I> has not yet been thoroughly characterized. Here, we investigate the <I>FLC</I> expression during gametogenesis and embryogenesis using <I>FLC::GUS</I> transgenic plants and RNA analysis. Regardless of the epigenetic state in adult plants, <I>FLC</I> expression disappeared in gametophytes. Subsequently, <I>FLC</I> expression was reactivated after fertilization in embryos, but not in the endosperm. Both parental alleles contributed equally to the expression of <I>FLC</I> in embryos. Surprisingly, the reactivation of <I>FLC</I> in early embryos was independent of FRIGIDA (FRI) and SUPPRESSOR OF FRIGIDA 4 (SUF4) activities. Instead, <I>FRI</I>, <I>SUF4</I> and autonomous-pathway genes determined the level of <I>FLC</I> expression only in late embryogenesis. Many <I>FLC</I> regulators exhibited expression patterns similar to that of <I>FLC</I>, indicating potential roles in <I>FLC</I> reprogramming. An <I>FVE</I> mutation caused ectopic expression of <I>FLC</I> in the endosperm. A mutation in <I>PHOTOPERIOD-INDEPENDENT EARLY FLOWERING 1</I> caused defects in <I>FLC</I> reactivation in early embryogenesis, and maintenance of full <I>FLC</I> expression in late embryogenesis. We also show that the polycomb group complex components, Fertilization-Independent endosperm and MEDEA, which mediate epigenetic regulation in seeds, are not relevant for <I>FLC</I> reprogramming. Based on our results, we propose that <I>FLC</I> reprogramming is composed of three phases: (i) repression in gametogenesis, (ii) reactivation in early embryogenesis and (iii) maintenance in late embryogenesis.</P>

TISSU E-SPECIFIC AND DEVELOPMENTAL REGULATION OF A GENE ENCODING A THIONIN-LIKE PROTEIN IN SOYBEAN SEEDS

Choi, Yeonhee,Ahn, Ji Hoon,Choi, Yang Do,Lee, Jong Seob Plant molecular biology and biotechnology research 1994 Proceedings the 2nd Korean-Germany joint symposium Vol.1994 No.-

Characterization of a Potato Proteinase Inhibitor Ⅱ Gene that Is Expressed Constitutively in Transgenic Tobacco plants

Choi, Yeonhee,Kim, Joo Won,Lee, Jong Seob Korean Society of Molecular Biology 1992 Molecules and cells Vol.2 No.2

Marginal Micro-Leakage of the Sealant according to the Enamel Preparation

Yeonhee Choi,Hyunkyung Oh 대한예방치과학회 2012 International Journal of Clinical Preventive Denti Vol.8 No.3

Objective: The author has experimented on the marginal leakage of the pit and fissure sealant by enamel preparation, according to the preparation and the proper sealant in clinical use. Methods: 3 kinds of the sealant was chosen and 84 permanent extracted Premolar for orthodontic treatment were selected by deviding with 6 groups, as applying etchant or etching after preparation with a Tungsten carvide bur, for 3 kinds of the sealant group. Methylen blue was applied to infiltrate from the margine of sealant for each group. Stereo microscope was used to observe the micro-leakage after cutting longitudinally, and measured the depth penetration by use of Raadal M method. The obtained results were as follows. Results: 1. The average degree of the micro-leakage were less in enamel preparation with bur group than in enamel etching group (p<0.01), otherwise, no significant different both in Clinpro sealant and Seal it groups (p>0.05). 2. The comparison of the micro- leakage was shown as higher in Seal-it and Bosthworth group than in Clinpro group, in enamel etching group (p<0.05), otherwise, heigher in Bosthworth group than Seal-it or Clinpro group, in enamel etching after preparation with bur group, in statistically, by Duncan test (p<0.05). Conclusion: Unfilled type of sealant was recommended to use for sound enamel sealing and both in unfilled and nano typed filler contained sealant were recommended to use for sealing on the initical caries lesion, in clinical.

사실과 재현의 관점에서 수인스님 다시보기

최연희(Yeonhee Choi) 중앙승가대학교 불교학연구원 2020 불교와 사회 Vol.12 No.2

본 연구는 ‘비구니 관련 자료와 연구의 부족’이라는 문제의식을 가지고 ‘사실과 재현’의 관점에서 근현대 시기에 활동한 1세대 비구니 스님들의 서술을 비판적으로 검토하는 데 목적이 있다. 이를 위해 수인스님과 운문사를 주제로 다룬 여러 텍스트에서 관련 서술을 정리하고 검토하였다. 분석결과, 비구니 사찰로의 전환에 대해서는 불교정화운동 시기에 여러 비구니 스님들의 노력으로 대처승과의 투쟁과 재판을 거쳐 운문사가 청정도량으로 전환되는 과정이 재현되지 않고 결과만이 서술되어 있었다. 때문에 당시 대처승으로부터 비구니 사찰을 지키기 위해 노력하였던 수인스님과 대중스님들의 노고가 망각된 채 후세에 전달하지 못하고 있다. 오늘날과 같은 대가람의 기초를 마련한 불사도 사실에 부합하게 재현되지 못하고 단편적인 사건들로 나열되고 있었다. 이로 인해 불교정화운동 시기부터 1960년대 중반까지 사찰을 되찾고 재건하는 일련의 과정을 주도하였던 수인스님은 ‘종교지도자’로서 기록되지 않고 있다. 운문사 발전의 기초를 마련하였던 당시 운문사 대중스님들과 지도자였던 수인스님의 원력과 성과를 의미 있는 역사로서 바로 세우고 기록하기 위해서 이제는 사실에 의거한 서술로의 수정작업이 필요하다. This paper intended to analyze the recent issues about Buddhist bhikkhuni, which were active in Korea in the 50s and 60s [the first-generation bhikkhuni]. For this purpose, this study reviewed critically the contents about the Buddhist monk Sooin at related books. This study results are so following: First, in the contents, only the result is described simply rather than the process of converting of Unmunsa Temple to Bhikkhuni Temple. Unmunsa Temple became a pure and sacred temple after overcoming struggles and trials with the married Buddhist monks during the period of the Buddhist Purification Movement. Because of this, the hard work of Sooin and temple community who tried to protect Unmunsa Temple from the married Buddhist monks at that time have been forgotten and have not been passed on to next generations. Second, the description regarding the reconstructions of temple buildings and temple works was focused to list as fragmentary events, not reproduced in accordance with the facts. For this reason, Sooin, who led the process of purifying and rebuilding temple from the period of the Buddhist purification movement to the mid-1960s, was not recorded as a “religious leader”. In order to correctly record and evaluate the vows and achievements of temple community and Sooin, who was the leader of the temple community at the time, when the foundation for the development of Unmunsa Temple was been laid, it is now necessary to revise the contents about Buddhist monk Sooin with fact-based content.

Laplacian of Gaussians (LoG)와 캐니 에지 검출법을 접목한 색상 보간 알고리듬

최연희(Yeonhee Choi),김일승(Ilseung Kim),정제창(Jechang Jeong) 한국방송·미디어공학회 2014 한국방송공학회 학술발표대회 논문집 Vol.2014 No.11

본 논문은 Laplacian of Gaussians (LoG)에 캐니 에지 검출 기법을 접목한 새로운 색상 보간 알고리듬을 제안한다. 캐니 에지 검출 기법은 영상 스무딩, 기울기 크기와 각도 계산, 세션화, 이중 문턱치 처리 과정으로 이루어진다. 이때 앞의 두 과정을 LoG를 이용하여 처리함으로써 기존의 캐니 애지 검출법보다 정확한 방향 정보를 얻을 수 있다. 실험결과를 통해 기존의 색상 보간 알고리듬에 비해 Peak Signal to Noise Ratio (CPSNR)이 상승함을 확인하였으며, 에지 영역 주변에서 발생하였던 무지개 에러가 현저히 감소하였음을 확인할 수 있었다.

비계층적 PKI에서의 인증 경로 처리 기법에 대한 새로운 방안

최연희(Yeonhee Choi),박미옥(Miog Park),추연수(Yeoun Soo Choo),전문석(Moonseog Jun) 한국정보과학회 2003 한국정보과학회 학술발표논문집 Vol.30 No.2Ⅰ

사용자 어플리케이션에서 인증 경로를 검증하는 일은 매우 복잡하고 많은 시간이 소요됨으로서의 사용자 측에 상당한 부담을 줄 수 있다. 특히, 비계층적 PKI에서의 검증 작업은 다수의 후보 경로가 존재함에 따라서 그 부담이 더욱 커진다. 따라서 본 논문에서는 비계층적 PKI의 인증 기관(Certificate Authority : CA)을 서명 검증 작업에 참여시킴으로서 사용자 측 검증 작업에 대한 부담을 감소시킬 수 있는 새로운 형태의 인증 경로 방안을 제안하였다. 제안한 방안은 서명 검증에 수반되는 사용자 측 암호화 작업을 크게 줄임으로서 검증에 대한 부담을 감소시킬 뿐만 아니라 CA들의 검증 작업의 참여로 인해 정적인 CA들의 활용도를 높일 수 있다.