Aspergillus nidulans의 분화생물학적 고찰

장광엽,채건상,한동민 전북대학교 유전공학연구소 1989 遺傳工學硏究所報 Vol.2 No.1

酵母의 形性質細胞 形性과 2μm-DNA, plasmid의 分離에 關하여

張光燁,朴文국 全北大學校 基礎科學硏究所 1985 基礎科學 Vol.8 No.1

The roles and functions of 2㎛ DNA plasmid which is an important element for the research on the molecular genetics of yeasts are still unknown. When the protoplast or spheroplast is produced from yeast, its intracelluar DNA can be easily isolated. The conditions for the production of protoplast from yeast were determined in this study. Aming the factors that affect of the production of protoplast are kinds and concentrations of osmotic stabilizers, growth phase of cells, and enzymes for lysis of cell wall. Six hundred mM of KCl or 1 M of Sorbitol was most efficient for pottoplast formation as osmotic stabilizer, The cells of mid-late exponential phase were well formed to protplasts, DNA plasmid was determined with agarose gel electrophoreis.

선택표지를 사용하지 않는 용이한 유전자 cloning방법

장광엽 전북대학교 유전공학연구소 1988 遺傳工學硏究所報 Vol.1 No.1

제한효소로 자른 DNA 조각을 vector의 선택표지 내가 아닌 다른 자리에 삽입하고자 할 때, 삽입된 vector를 쉽게 얻을 수 있는 방법을 기술하였다. 기술된 방법으로 효모의 세포주기 조절유전자 CDC73을 함유하고 있는 HindⅢ 조각을 vector YCp50와 pHSS8의 HindⅢ자리에 삽입시켜 만족할 만한 결과를 얻었다. The cloning procedure in which DNA fragment inserted into the outer region of seletive marker in vectors was explained in this article. A DNA fragment containing the gene CDC73 which had been cut by the restriction endonuclease HindⅢ was cloned into the vectors YCp50 and pHSS8 by the explained procedure.

효모의 접합과정에 관여하는 유전자의 연구

장광엽,박문국,정봉우 全北大學校 基礎科學硏究所 1991 基礎科學 Vol.14 No.1

효모의 mating과정의 기작을 연구하기 위하여, α pheromone의 수용체를 coding하는 유전자인 STE2가 결여된 균주로 하여금 mating을 할 수 있게 하는 61개의 돌연변이를 획득하였다. 이들은 상보성시험과 연관시험 결과 3개 군의 유전자에 속했는데, 3개 군을 CDC70, CDC72 및 CDC73 이라고 명명하였다. 얻어진 돌연변이는 제한 온도에서는 세포분열이 start 단계에서 정지되는 온도 감수성이며 STE2 유전자 결여를 억제하는 능력을 보여 주었는데, 이는 유전자 CDC70, CDC72, CDC73 의 생성물이 수용체로부터 전달되는 signal의 중간 전달 물질이라는 사실을 가리킨다. In order to elucidate and characterize the signal transduction pathway(s) whereby yeast cells respond to mating pheromone, we have isolated mutants which are able to conjugate in the absence of the alpha-factor receptor. Sixty-one suppressors of a ste2-deletion mutation which also confer a ts conditional "start" arrest phenotype have been subjected to genetic analysis. The mutants could be assigned to three complementation groups designated CDC70, CDC72 and CDC73, which are unlinked to each other as well as to the previously identified start genes. Quantitation of mating ability of the cdc70, cdc72 and cdc73 mutations in a ste2-deletion background gives levels ranging from 0.1% to 0.3% of wild type, depending on the allele and the gene. The results indicate that the signals from mating pheromone might be mediated by the CDC70, CDC72 and CDC73 products.

Aspergillus nidulans에 있어서 무성포자 생성의 억제조건과 이를 이용한 유성포자생성결손 돌연변이주의 분리

한동민,장광엽,채건상 전북대학교 유전공학연구소 1989 遺傳工學硏究所報 Vol.2 No.1

In order to find an useful condition under which the mutants defective in sexual development could be isolated, the effects of several cultural conditions on the developments of Aspergillus nidulans were examined. Among the several conditions found to restrict the asexual sporulation but enhance the sexual process, the interference of aeration by sealing the plates with sealing film was the most useful one for the purpose of mutant isolation. Sealing at any time before 20 hours from inoculation prevented both sexual and asexual processes. When the seal was removed after 24 hours from inoculation, however, the mycelia developed only to sexual organs. Using this propertiy, the early morphogenic process of sexual development could be observed and several mutants that showed some defects in the process could be isolated. The mutants were divided into 3 groups, NSD(never in sexual development), BSD(block in sexual development) and ASD(abnormal in sexual development). NSD mutants never developed either the Hulle cells or cleistothecia and they produced the asexual organs even when the aeration was restriced. BSD mutants were blocked in any process of the Hulle cell, cleistothecium, crozier, ascus or ascospore formation. ASD mutants had defects in the amount of clestothecia maturation or color of ascospores.

미생물을 이용한 Gellan Gum 생성의 Kinetic에 관한 연구

金春永,鄭奉佑,張光燁,李銀美 全北大學校 1992 論文集 Vol.34 No.-

Polysaccharides produced microbially, have shown themselves to be commercially significant. The reasons for the commercial exploitation of these microbial polysaccharides is because of their unique physical and consistant chemical properties and regularity of supply. Gellan gum is a recently discovered extracellular polysaccaride. This is an anionic heteropolysaccharide that forms viscous solutions and can under certain conditions, form thermoreversible gels with characteristics similar to those formed by both carrigeenan and agar. The aspect of Gellan gum produced by Pseudomonas elodea were investigated under various concentration of carbon sources and nitrogen sources. Sucrose and glucose are used as carbon source, and Bacto-peptone, Promosoy and (NH_4)_2SO_4 are used as nitrogen source. The maximum Gellan gum production was obtained in the culture medium 30.0g/L glucose, 0.6g/L Promosoy at pH 6.6, 37℃. The molecular weight of Gellan gum was 5 × 10 exp (5) which was determined by gel permeation chromatography.

The α-subunit of a Saccharomyces cerevisiae G protein plays a role in mating pheromone signaling

Jahng, Kwang Yeop 한국균학회 1988 韓國菌學會誌 Vol.16 No.3

G proteins represent a group of highly homologous proteins involved in receptor mediated signal transduction. They apparently serve as informational transducers between a diverse group of cell surface receptors and an equally diverse assortment of second message effectors. In vertebrates, G proteins have been to be ubiquitous in terms of their tissue and phylogenetic distribution. Mutations which allowed conjugation by Saccharomyces cerevisiae cells lacking a mating pheromone receptor gene were selected. One of the genes defined by such mutations was isolated from a yeast genomic library by complementation of a is mutation and is identical to the gene GPA1 (also known as SCG1), recently shown to be highly homologous to genes encoding the subunits of mammalian G proteins. Physiological analysis of temperature sensitive gpal mutations suggests that the encoded G protein is involved in signalling in response to mating pheromones. Mutational disruption of G protein activity causes cell cycle arrest in G1, deposition of mating-specific cell surface agglutinins and induction of pheromone-specific mRNAs, all of which are responses to pheromone in wild type cells. In addition, mutants can conjugate without the benefit of mating pheromone or pheromone receptor.

Heat Inducible Expression of the CDC70 Gene Under the Control of Heat Shock Element in Saccharomyces Cerevisiae

Lee, Seok-Jae,Jahng, Kwang-Yeop,Lee, Young-Hoon,Chae, Keon-Sang The Microbiological Society of Korea 1995 The journal of microbiology Vol.33 No.3

In order to express the CDC70 gene of Saccharomyces cerevisiae by heat shock, we have designed heat inducibe hybrid promoters using the Drosophila melanogaster heat shock elements (HSEs). A 220 bp-long upstream fragment of the D. melanogaster hsp70 gene comprised of four HSEs was placed upstream of the putative proximal TATA box of the CDC70 gene. Hybrid promoters containing different fusion joints were tested for their ability to drive the CDC70 gene expression by heat shock. The results showed that the HSEs of D. melanogaster conferred the heat-induced CDC70 gene expression, but the heat inducibility was much lower than that in D. melanogaster.

A report on 33 unrecorded bacterial species of Korea isolated in 2014, belonging to the class Gammaproteobacteria

Lim, Yeonjung,Joung, Yochan,Nam, Gi Gyun,Jahng, Kwang-Yeop,Kim, Seung-Bum,Joh, Ki-seong,Cha, Chang-Jun,Seong, Chi-Nam,Bae, Jin-Woo,Im, Wan-Taek,Cho, Jang-Cheon The National Institute of Biological Resources 2016 Journal of species research Vol.5 No.2

In 2014, as a subset study to discover indigenous prokaryotic species in Korea, a total of 33 bacterial strains assigned to the class Gammaproteobacteria were isolated from diverse environmental samples collected from soil, tidal flat, freshwater, seawater, oil-contaminated soil, and guts of animal. From the high 16S rRNA gene sequence similarity (>98.5%) and formation of a robust phylogenetic clade with the closest species, it was determined that each strain belonged to each independent and predefined bacterial species. There is no official report that these 33 species have been described in Korea; therefore, 1 strain of the Aeromonadales, 6 strains of the Alteromonadales, 3 strains of the Chromatiales, 5 strains of the Enterobacteriales, 4 strains of the Oceanospirillales, 11 strains of the Pseudomonadales, and 3 strains of the Xanthomonadales within the Gammaproteobacteria are described for unreported bacterial species in Korea. Gram reaction, colony and cell morphology, basic biochemical characteristics, and isolation sources are also described in the species description section.

<i>Pedobacter pituitosus</i> sp. nov., isolated from a waterfall

Chun, Jeesun,Kang, Ji Young,Jahng, Kwang Yeop International Union of Microbiological Societies 2014 International journal of systematic and evolutiona Vol.64 No.11

<P>A taxonomic study was carried out on a novel bacterial strain, designated MIC2002<SUP>T</SUP>, which was isolated from Wibong falls in Korea. Cells were Gram-stain-negative, aerobic, non-motile and rods, 0.3–0.5 µm wide and 4.0–5.0 µm long. The optimum temperature and pH range for growth were 25 °C and pH 6.5–7.0, respectively. Catalase and oxidase activities were positive. Flexirubin pigments were not produced. Comparison of the 16S rRNA gene sequences indicated that the isolate belonged to the genus <I>Pedobacter</I>, with <I>Pedobacter daechungensis</I> as its closest relative, with a similarity of 94.4 %. It contained iso-C<SUB>15 : 0</SUB>, anteiso-C<SUB>15 : 0</SUB>, C<SUB>16 : 0</SUB>, summed feature 3 (C<SUB>16 : 1</SUB>ω6<I>c</I> and/or C<SUB>16 : 1</SUB>ω7<I>c</I>) and iso-C<SUB>17 : 0</SUB> 3-OH as the major fatty acids and menaquinone MK-7 as isoprenoid quinone. The polar lipid profile of strain MIC2002<SUP>T</SUP> revealed the presence of phosphatidylethanolamine and an unknown lipid. The DNA G+C content of the strain was 34.7 mol%. On the basis of the evidences presented, it was concluded that strain MIC2002<SUP>T</SUP> represents a novel species of the genus <I>Pedobacter</I> within the family <I>Sphingobacteriaceae</I>, for which the name <I>Pedobacter</I> <I>pituitosus</I> sp. nov. is proposed. The type strain is MIC2002<SUP>T</SUP> ( = KACC 17064<SUP>T</SUP> = JCM 18729<SUP>T</SUP>).</P>