61 results on '"Keon-Sang Chae"'
Search Results
2. TheAspergillus nidulansVelvet-interacting protein, VipA, is involved in light-stimulated heme biosynthesis
- Author
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Julian Röhrig, Reinhard Fischer, Zhenzhong Yu, Jong-Hwa Kim, Kap-Hoon Han, and Keon-Sang Chae
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0301 basic medicine ,chemistry.chemical_classification ,Phytochrome ,biology ,030106 microbiology ,Mutant ,Fungal genetics ,biology.organism_classification ,Microbiology ,Amino acid ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,chemistry ,Biochemistry ,Aspergillus nidulans ,Dehydratase ,Molecular Biology ,Heme ,Transcription factor - Abstract
Filamentous fungi are able to differentiate morphologically and adapt the metabolism to internal and external cues. One major regulator is the so-called velvet protein, VeA, best studied in Aspergillus nidulans. The protein interacts with several other proteins to regulate light sensing, the balance between asexual and sexual development, penicillin biosynthesis or mycotoxin production. Here, we characterized a novel VeA-interacting protein, VipA. The 334 amino acid long protein comprises a FAR1-like DNA-binding domain, known from plant transcription factors like FHY3 (Far-red elongated hypocotyl 3). VipA interacted not only with VeA, but also with the WC orthologue LreA in the nuclei and with the phytochrome FphA in the cytoplasm. Conidia and cleistothecia formation was similarly affected in a vipA-deletion strain as in an fphA mutant. However, the effect was less pronounced, suggesting a modulating and not an essential role in light sensing. In addition, VipA modulated heme biosynthesis in response to light through association with the hemB promoter, the gene encoding 5-aminolevulinic acid dehydratase. After illumination of A. nidulans mycelia with white light the intracellular heme concentration increased by 30% in comparison to a vipA-deletion mutant. Hence, VipA couples heme biosynthesis to the illumination conditions.
- Published
- 2017
3. Characterization of NpgA, a 4′-phosphopantetheinyl transferase of Aspergillus nidulans, and evidence of its involvement in fungal growth and formation of conidia and cleistothecia for development
- Author
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Kwang-Yeop Jahng, Keon-Sang Chae, Ha-Yeon Song, Dong-Min Han, Hyo-Jin Choi, Jung-Mi Kim, Kum-Kang So, and Dae-Hyuk Kim
- Subjects
Mutant ,Saccharomyces cerevisiae ,Transferases (Other Substituted Phosphate Groups) ,Applied Microbiology and Biotechnology ,Microbiology ,Aspergillus nidulans ,Fungal Proteins ,Sexual sporulation ,Bacterial Proteins ,Cell Wall ,Gene Expression Regulation, Fungal ,Reproduction, Asexual ,Gene ,Genetics ,biology ,Pigmentation ,Wild type ,4'-phosphopantetheinyl transferase ,Sequence Analysis, DNA ,General Medicine ,Spores, Fungal ,Thionucleotides ,biology.organism_classification ,Phenotype ,Cell biology ,Adenosine Diphosphate ,Mutation - Abstract
The null pigmentation mutant (npgA1) in Aspergillus nidulans results in a phenotype with colorless organs, decreased branching growth, delayed of asexual spore development, and aberrant cell wall structure. The npgA gene was isolated from A. nidulans to investigate these pleiomorphic phenomena of npgA1 mutant. Sequencing analysis of the complementing gene indicated that it contained a 4'-phosphopantetheinyl transferase (PPTase) superfamily domain. Enzymatic assay of the PPTase, encoded by the npgA gene, was implemented in vivo and in vitro. Loss-of-function of LYS5, which encoded a PPTase in Saccharomyces cerevisiae, was functionally complemented by NpgA, and Escherichia coli-derived NpgA revealed phosphopantetheinylation activity with the elaboration of 3'5'-ADP. Deletion of the npgA gene caused perfectly a lethal phenotype and the absence of asexual/sexual sporulation and secondary metabolites such as pigments in A. nidulans. However, a cross feeding effect with A. nidulans wild type allowed recovery from deletion defects, and phased-culture filtrate from the wild type were used to verify that the npgA gene was essential for formation of metabolites needed for development as well as growth. In addition, forced expression of npgA promoted the formation of conidia and cleistothecia as well as growth. These results indicate that the npgA gene is involved in the phosphopantetheinylation required for primary biological processes such as growth, asexual/sexual development, and the synthesis of secondary metabolites in A. nidulans.
- Published
- 2015
4. Membrane-Bound Methyltransferase Complex VapA-VipC-VapB Guides Epigenetic Control of Fungal Development
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Alexander Kaever, Ivo Feussner, Gerhard H. Braus, Özlem Sarikaya-Bayram, Kap-Hoon Han, Özgür Bayram, Kirstin Feussner, Hee-Seo Kim, Dong-Min Han, Jong-Hwa Kim, and Keon-Sang Chae
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Transcription, Genetic ,Molecular Sequence Data ,Active Transport, Cell Nucleus ,Vesicular Transport Proteins ,Biology ,Aspergillus nidulans ,General Biochemistry, Genetics and Molecular Biology ,Epigenesis, Genetic ,Fungal Proteins ,Histones ,03 medical and health sciences ,Gene Expression Regulation, Fungal ,Heterochromatin ,Transcriptional regulation ,Molecular Biology ,Transcription factor ,030304 developmental biology ,Cell Nucleus ,Genetics ,Regulation of gene expression ,0303 health sciences ,Fungal protein ,030306 microbiology ,Methyltransferase complex ,Cell Membrane ,Fungal genetics ,Gene Expression Regulation, Developmental ,Methyltransferases ,Cell Biology ,DNA Methylation ,Spores, Fungal ,VAPB ,DNA-Binding Proteins ,Protein Transport ,Nuclear transport ,Signal Transduction ,Transcription Factors ,Developmental Biology - Abstract
SummaryEpigenetic and transcriptional control of gene expression must be coordinated in response to external signals to promote alternative multicellular developmental programs. The membrane-associated trimeric complex VapA-VipC-VapB controls a signal transduction pathway for fungal differentiation. The VipC-VapB methyltransferases are tethered to the membrane by the FYVE-like zinc finger protein VapA, allowing the nuclear VelB-VeA-LaeA complex to activate transcription for sexual development. Once the release from VapA is triggered, VipC-VapB is transported into the nucleus. VipC-VapB physically interacts with VeA and reduces its nuclear import and protein stability, thereby reducing the nuclear VelB-VeA-LaeA complex. Nuclear VapB methyltransferase diminishes the establishment of facultative heterochromatin by decreasing histone 3 lysine 9 trimethylation (H3K9me3). This favors activation of the regulatory genes brlA and abaA, which promote the asexual program. The VapA-VipC-VapB methyltransferase pathway combines control of nuclear import and stability of transcription factors with histone modification to foster appropriate differentiation responses.
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- 2014
5. The MpkB MAP kinase plays a role in autolysis and conidiation of Aspergillus nidulans
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Ji Young Kang, Jeesun Chun, Kwang Yeop Jahng, Dong-Min Han, Keon-Sang Chae, and Sang-Cheol Jun
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Mitogen-Activated Protein Kinase Kinases ,Autolysis (biology) ,Microbial Viability ,biology ,Hypha ,Saccharomyces cerevisiae ,Hyphae ,Wild type ,Conidiation ,Spores, Fungal ,Glucanase ,biology.organism_classification ,Microbiology ,Aspergillus nidulans ,Gene Expression Regulation, Fungal ,Genetics ,Gene family ,Autolysis ,Gene Deletion - Abstract
The mpkB gene of Aspergillus nidulans encodes a MAP kinase homologous to Fus3p of Saccharomyces cerevisiae which is involved in conjugation process. MpkB is required for completing the sexual development at the anastomosis and post-karyogamy stages. The mpkB deletion strain could produce conidia under the repression condition of conidiation such as sealing and even in the submerged culture concomitant with persistent brlA expression, implying that MpkB might have a role in timely regulation of brlA expression. The submerged culture of the deletion strain showed typical autolytic phenotypes including decrease in dry cell mass (DCM), disorganization of mycelial balls, and fragmentation of hyphae. The chiB, engA and pepJ genes which are encoding cell wall hydrolytic enzymes were transcribed highly in the submerged culture. Also, we observed that the enzyme activity of chitinase and glucanase in the submerged culture of mpkB deletion strain was much higher than that of wild type. The deletion of mpkB also caused a precocious germination of conidia and reduction of spore viability. The expression of the vosA gene, a member of velvet gene family, was not observed in the mpkB deletion strain. These results suggest that MpkB should have multiple roles in germination and viability of conidia, conidiation and autolysis through regulating the expression of vosA and brlA.
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- 2013
6. The Aspergillus nidulans Velvet-interacting protein, VipA, is involved in light-stimulated heme biosynthesis
- Author
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Julian, Röhrig, Zhenzhong, Yu, Keon-Sang, Chae, Jong-Hwa, Kim, Kap-Hoon, Han, and Reinhard, Fischer
- Subjects
Cell Nucleus ,Fungal Proteins ,Light ,Gene Expression Regulation, Fungal ,Heme ,Phytochrome ,Mycotoxins ,Promoter Regions, Genetic ,Aspergillus nidulans ,Transcription Factors - Abstract
Filamentous fungi are able to differentiate morphologically and adapt the metabolism to internal and external cues. One major regulator is the so-called velvet protein, VeA, best studied in Aspergillus nidulans. The protein interacts with several other proteins to regulate light sensing, the balance between asexual and sexual development, penicillin biosynthesis or mycotoxin production. Here, we characterized a novel VeA-interacting protein, VipA. The 334 amino acid long protein comprises a FAR1-like DNA-binding domain, known from plant transcription factors like FHY3 (Far-red elongated hypocotyl 3). VipA interacted not only with VeA, but also with the WC orthologue LreA in the nuclei and with the phytochrome FphA in the cytoplasm. Conidia and cleistothecia formation was similarly affected in a vipA-deletion strain as in an fphA mutant. However, the effect was less pronounced, suggesting a modulating and not an essential role in light sensing. In addition, VipA modulated heme biosynthesis in response to light through association with the hemB promoter, the gene encoding 5-aminolevulinic acid dehydratase. After illumination of A. nidulans mycelia with white light the intracellular heme concentration increased by 30% in comparison to a vipA-deletion mutant. Hence, VipA couples heme biosynthesis to the illumination conditions.
- Published
- 2015
7. The MpkB MAP kinase plays a role in post-karyogamy processes as well as in hyphal anastomosis during sexual development in Aspergillus nidulans
- Author
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Dong-Min Han, Jung-Mi Kim, Hwan-Gyu Kim, Seung-Hwan Jang, Hyun-Joo Park, Sang-Cheol Jun, Jiyoung Kang, Mi-Hee Chang, Young-Eun Leem, Sei-Jin Lee, Kwang-Yeop Jahng, Keon-Sang Chae, and Tae-Ho Yang
- Subjects
Hyphal growth ,Genes, Fungal ,Molecular Sequence Data ,Mutant ,Hyphae ,Applied Microbiology and Biotechnology ,Microbiology ,Aspergillus nidulans ,Karyogamy ,Fungal Proteins ,Gene Expression Regulation, Fungal ,Cloning, Molecular ,Gene ,Heterokaryon ,Genetics ,biology ,fungi ,Wild type ,Sequence Analysis, DNA ,General Medicine ,biology.organism_classification ,Phenotype ,Meiosis ,Mitogen-Activated Protein Kinases ,Gene Deletion - Abstract
Two genes encoding MAP kinase homologs, designated as mpkB and mpkC, were isolated from Aspergillus nidulans by PCR with degenerate primers. Deletion and over-expression mutants of mpkC showed no detectable phenotypes under any external stress tested. Deletion of mpkB caused pleiotropic phenotypes including a failure in forming cleistothecia under any induction conditions for sexual development, increased Hülle cell production, slow hyphal growth and aberrant conidiophore morphology. Over-expression of mpkB led to increased cleistothecium production. While the transcripts of mpkB and mpkC were constitutively synthesized through the entire life cycle, their size and amount differed with developmental stages. An outcross test using fluorescent protein reporters showed that the mpkB deletion mutant could not form heterokaryons with wild type. Protoplast fusion experiments showed that the fusant of the mpkB mutant with wild type could undergo normal sexual development. However, heterokaryotic mycelia that were produced from a fusant between two mpkB deletion mutants could not form cleistothecia, although they did appear to form diploid nuclei. These results suggest that the MpkB MAP kinase is required for some post-karyogamy process as well as at the hyphal anastomosis stage to accomplish sexual development successfully.
- Published
- 2011
8. The nsdC Gene Encoding a Putative C2H2-Type Transcription Factor Is a Key Activator of Sexual Development in Aspergillus nidulans
- Author
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Keon-Sang Chae, Dong-Min Han, Kap-Hoon Han, and Hye-Ryun Kim
- Subjects
Glycerol ,Time Factors ,RNA Splicing ,Molecular Sequence Data ,Lactose ,Asexual sporulation ,Acetates ,Investigations ,Aspergillus nidulans ,Fungal Proteins ,Gene Expression Regulation, Fungal ,Genetics ,Amino Acid Sequence ,RNA, Messenger ,Gene ,Transcription factor ,Regulation of gene expression ,Zinc finger ,Mycelium ,Sequence Homology, Amino Acid ,biology ,Reverse Transcriptase Polymerase Chain Reaction ,Activator (genetics) ,Gene Expression Regulation, Developmental ,RNA ,Zinc Fingers ,Spores, Fungal ,Blotting, Northern ,biology.organism_classification ,Introns ,DNA-Binding Proteins ,Glucose ,Mutation ,Transcription Factors - Abstract
The formation of the Aspergillus nidulans fruiting body is affected by a number of genetic and environmental factors. Here, the nsdC (never in sexual development) gene—encoding a putative transcription factor carrying a novel type of zinc-finger DNA-binding domain consisting of two C2H2's and a C2HC motif that are highly conserved in most fungi but not in plants or animals—was investigated. Two distinct transcripts of 2.6 and 3.0 kb were generated from nsdC. The 2.6-kb mRNA accumulated differentially in various stages of growth and development, while the level of the 3.0-kb mRNA remained relatively constant throughout the life cycle. While the deletion of nsdC resulted in the complete loss of fruiting body formation under all conditions favoring sexual development, overexpression of nsdC not only enhanced formation of fruiting bodies (cleistothecia) but also overcame inhibitory effects of certain stresses on cleistothecial development, implying that NsdC is a key positive regulator of sexual development. Deletion of nsdC also retarded vegetative growth and hyperactive asexual sporulation, suggesting that NsdC is necessary not only for sexual development but also for regulating asexual sporulation negatively. Overexpression of veA or nsdD does not rescue the failure of fruiting body formation caused by nsdC deletion. Furthermore, nsdC expression is not affected by either VeA or NsdD, and vice versa, indicating that NsdC regulates sexual development independently of VeA or NsdD.
- Published
- 2009
9. Abstracts of Presentations at the 2007 Spring Meeting of the Korean Society of Mycology at the Chonnam National University, Gwangju, Korea, May 4
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Hye-Young Yu, Jeong-Ah Seo, Kap-Hoon Han, Sung-Hwan Yun, Yin-Won Lee, Kang-Hyeon Ka, Ji-Youn Chang, Sung-Ryul Ryu, Kab-Hee Yoon, Won-Chull Bak, Joon-Moh Park, Deuk-Sil Oh, Woo-Jae Cheon, Bong-Hun Lee, Yun-Hae Lee, Myoung-Jun Jang, Young-Cheol Ju, Woo-Sik Jo, Young-Hyun Rew, Sung-Guk Choi, Jae-Youl Uhm, Hoon Cho, Heung-Sun Sim, Byung-Wook Jo, Ying Wu, Cheol-Hee Choi, Woon-Seob Shin, Yu Lan Piao, Eun Jae Kim, Hye Yeon Mun, Kook Hwa Seo, Hyang Burm Lee, Heng Luo, Xinli Wei, Keon Seon Han, Young Jin Koh, Jae-Seoun Hur, Kwang-Choon Chang, In-Pyo Hong, Se-Kwon Kim, Jae-Ouk Shim, Ji-Yul Lee, Tae-Soo Lee, Min-Woong Lee, Wi Young Lee, Jin Kwon Ahn, Kang Hyeon Ka, Soo-Yong Song, Jeong-Hee Yun, Sang-Jun Kim, Ahn-Heum Eom, Eun-Hwa Lee, Suk Kim, Chang-Seok Lee, Yong-Seok Choi, Jae-Jin Kim, Young Woon Lim, Gyu-Hyeok Kim, Dae-Hyung Lee, Jae-Ho Kim, Kyo-Chul Koo, Dae-Hyoung Lee, Seung-Chan Jeong, Hyung-Eun Yoo, Jong-Soo Lee, Ahmed Imtiaj, Chandana Jayasinghe, Gun Woo Lee, Sang-Beom Kim, Yong Tae Jeong, Byung Keun Yang, Rezuanul Islam, Yu Sun Jung, Sang Min Kim, Chi Hyun Song, Sung-Hee Nam, Gyoo-Byung Sung, In-Mo Cheng, Hyeon Hur, Shun-Xing Guo, Young-Sang Choi, Hong Kyu Kim, Ka-Soon Lee, Dal-Soo Jhune, Jae-Mo Sung, Kyong-Cheol Ko, Sang Hyun Park, Hui Jeong Gwon, Yoshiyuki Kamio, Phuntip Poonpairoj, Yong-Sun Bahn, Young-Joon Ko, Joseph Heitman, In Ho Jeong, Mi Ra Park, Myoung Taek Lim, Kyu San Lee, Sung Je Cho, Gyoung Hee Kim, Sun Ho Shin, Hyun Su Park, Jong Sup Shin, Jong Young Yoon, Dong Heon Lee, Kyu Jin Yum, Myungkil Kim, Sun-Hwa Ryu, A-Young Lee, Bo-Young Kim, Kyung-Eun Lee, Young Hyun Kim, Hyoun-Su Lee, Joung Yoon Back, Young-Seok Kim, Man-Deuk Han, Ju-Yeon Sim, Kyung-Ha Yoon, Seung-Han Oh, Yoon Soo Han, Je-O Lee, Bhushan Shrestha, Sang-Kuk Han, Beom-Suk Kim, Gan-Joo Lee, Tae-Woong Kim, Ho-Gyoung Kim, Won-Ho Lee, Eun-Jung Ham, Sung-Su Park, Yong-Seon Yoo, Soo-Young Lee, Mi-Jeong Park, Young-Joon Choi, Seung-Beom Hong, Hyeon-Dong Shin, Jae-Gu Han, Sang Beom Kim, Geon Woo Lee, Tae Soo Lee, Mi Ja Shim, Chang-Won Lee, Hyun-Su Rho, Hyun Sook Lee, Min Woong Lee, U Youn Lee, Mi Sun Kim, Soon Ja Seok, Hack Sung Jung, Ji Yeon Oh, Sun Young Lee, Mun Il Ryoo, Ki Deok Kim, Hyo-Kyoung Won, Sung-Soon Kim, Dong-Gyu Kim, Song-Hee Lee, Hyeon-Su Ro, Hyun-Sook Lee, Narayan Chandra Paul, Won Ki Kim, Sung Kyoon Woo, Seung Hun Yu, So Hee Yun, Eun-Young Seo, Mi-Ran Lee, Chang Sun Kim, Won-Sik Kong, Kyeong-In Seo, Soon-Young Park, Kab-Yeul Jang, Young-Bok Yoo, Kwang-Ho Kim, Keun Kim, Quyvang Le, Shanliang Shi, Min Woo Hyun, Wook-Ha Park, Seung Yeol Son, Seong Hwan Kim, Kye Seung Jang, Wook Ha Park, Dong Youn Suh, Hyuk Woo Kwon, In Joung Back, Eun Sil Choi, Han Gyu Go, Chang Hyun You, Heon Dal Yoo, Yeo Hong Yun, Hyo Sun Jang, Young Bok Yoo, Won Sik Kong, Kab Yeul Jang, In Yeup Kim, Se Jong Oh, Chang Sung Jhune, Hyoun-Young Kim, Jong Hwa Kim, Yeong-Man Yu, Pil-Jae Maeng, Hee-Moon Park, Suhn-Kee Chae, Keon-Sang Chae, Kwang-Yeop Jahng, Dong-Min Han, Yoon-Gyo Lee, Jae-Chang Lee, Ki-Chul Chung, Kyung-ju Jung, Hyung-Guk Choi, In-Jin Park, and Duk-Soo Choi
- Subjects
geography ,Infectious Diseases ,geography.geographical_feature_category ,Sparassis crispa ,biology ,Mycology ,Spring (hydrology) ,Botany ,Gibberella ,biology.organism_classification ,Microbiology - Abstract
Functional Analyses of Three Gα and One Gβ Subunits in Gibberella zeaeComparison between Wild Strains of Pitoporus betulinus Collected from a Single TreeEcological Study of Sparassis crispa in Gwan...
- Published
- 2007
10. Abstracts of Presentations at the 2006 Fall Meeting of the Korean Society of Mycology at the Seoul Kyoyuk Munhwa Hoekwan, Seoul, Korea, October 19–20
- Author
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Yong-Bo Lee, Young-Hee Na, Chae-Kyu Lim, In-Hoa Jang, Dong-Kyoung Jang, Seong-Eun Yun, Sin-Ae Park, Sung-Hee Lim, Hyeon-Na Cho, Mi-Kyeong Lee, Yue-Qin Xiao, Young Jin Koh, Jae-Seoun Hur, Kwang-Mi Lim, Yoshikazu Yamamoto, Young-Ah Jeon, Hyo-Jin Kim, Myoung-Sook Shin, Seung-Joo Go, Seung-Beom Hong, Duck-Hyun Cho, Jin Sung Lee, Hack Sung Jung, Jae-Gu Han, Hyeon-Dong Shin, Young-Joon Choi, Dae-Ho Kim, Young-ah Jeon, Seung-Ju Go, Jong-Kyu Lee, Kab-Yeul Jang, Sun-Gyu Choi, Won-Sik Kong, Young-Bok Yoo, Gyu-Hyun Kim, Jae-Mo Sung, Jin Hee Kim, Ji Sun Lee, Ji Young Seo, Hyun-Su Rho, Hyun Sook Lee, Min Woong Lee, U-Youn Lee, Tae Soo Lee, Min Woo Hyun, Wook Ha Park, Ji Hye Kim, Jin Su Kim, Seung Kyu Lee, Kyung Hee Kim, Seong Hwan Kim, Imtiaj Ahmed, Jayasinghe Chandana, Sang Beom Kim, Ji Yeon Oh, Sam Nyu Jee, Hojoung Lee, Mun Il Ryoo, Ki Deok Kim, Sang Hyeon Park, Ahn Heum Eom, Narayan Chandra Paul, Won Ki Kim, Sung Kyoon Woo, Yun Woo Jang, Myung Soo Park, Seung Hun Yu, Miyeong Sim, Ahn-Heum Eom, Eun-Hwa Lee, Suk Kim, Yoo Mee Lee, Eui Nam Kim, Gun Woo Lee, VU Van Hanh, Suk Il Hong, Keun Kim, Keum Chul Shin, Jong Kyu Lee, Jong-Gab Jung, Moo-Hee Mun, Sang-Cheol Jun, Kyu-Joong Kim, Sang-Woo Kim, Young-Jae Kim, Eun-Jung Kim, Ji-Seon Min, Youn-Su Lee, Seung-Bin Kim, Moo-Young Jung, Man-Su Yu, Dong-Jun Kim, Hak-Ro Youn, Sung-Man Han, Kye Seung Jang, Yeo Hong Yun, Hun Dal Yoo, Hyo Sun Jang, Chung Hwa Lee, Je-O Lee, Sang-Kuk Han, Eun-Jeong Ham, Bhushan Shrestha, Ho-Kyoung Kim, Tae-Woong Kim, Won-Ho Lee, Su-Young Lee, Cheol-Soon Ko, Beom-Suk Kim, Jinju Kim, Hyun-Sook Lee, Hyeon-Su Ro, Kwang-Joon Chang, Kang-Hyeon Ka, Hyeon Hur, In-Pyo Hong, Jae-Ouk Shim, Tae-Soo Lee, Ji-Yul Lee, Min-Woong Lee, Ji Hwan Yoon, Ji Eun Park, Hyun Seok Jo, Dong Yeon Suh, Seung Beom Hong, Seung Ju Ko, Heng Luo, Mei Rong Ren, Kwon-Il Seo, Soon-Ok Rim, Jin-Hyung Lee, In-Joong Lee, In-Koo Rhee, Jong-Guk Kim, Sun Hwa Ryu, A Young Lee, Hee Kyoung Sohn, Myung Kil Kim, Ja-Young Yoon, Yun-Hee Park, Hee-Moon Park, Joong-Keun Lee, Seung-Moon Park, Moon-Sik Yang, Tai-Boong Uhm, Dae-Hyuk Kim, In-Yeup Kim, Chang-Sung Jhune, Kwang-Ho Kim, Young Bok Yoo, Won Sik Kong, Kab Yeul Jang, In Yeup Kim, Se Jong Oh, Chang Sung Jhune, Hye Jin Kwon, Yong Jin Park, Kap-Hoon Han, Yeong-Man Yu, Hyoun-Young Kim, Mi-Hee Choi, Pil-Jae Maeng, Jong Hwa Kim, Suhn-Kee Chae, Keon-Sang Chae, Kwang-Yeop Jahng, Dong-Min Han, Yaya Rukayadi, Jae-Kwan Hwang, Dong-Gyu Kim, Sung-Soon Kim, Jun-Oh Choi, Hyo-kyoung Won, Ji-Young Bae, Jung-Ah Choi, Sunhwa Moon, Jung-Bin Park, Eun-Hee Yang, Young-Hun Jin, Mi-Sun Lee, Mu-Seok Seo, Gun-A Kim, Seok-Tae Kwon, Young-Kyung Lee, Bum-Soo Hahn, Gi-Yong Kim, Beong-Yeol Sung, Jong-Bum Kim, Joo-Sung Yang, Seung Ho Lee, Mi Ja Shim, Jae Ouk Shim, Yoon Hee Lee, Jung Sun Lee, Hyun Guell Kim, Kyu Chan Cho, Yong Il Park, Wi Young Lee, Jin Kwon Ahn, Youngki Park, Kang Hyeon Ka, Jeong Weon Yoon, Sung Woo Choi, Hee Kuk Park, Won Jin Yu, Sung Pil Lee, Ae Kyung Juen, Won Woo Kim, Sang Mong Lee, Namsook Park, Eunju Park, Byung Rae Jin, Hong Kyu Kim, Yong Gyun Kim, Gwan Seuk Seo, Se Hyun Oh, Hong Gi Kim, Nam Gyu Kim, Sung Woo Kang, and Jung Bae Kim
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Myelochroa ,Euphoriomyces ,Opuntiella ,Infectious Diseases ,Genus ,Anthropology ,Mycology ,Laboulbeniales ,Biology ,biology.organism_classification ,Microbiology - Abstract
Notes on Three Species of the Genus Euphoriomyces (Laboulbeniales) from KoreaTaxonomic Studies on Myelochroa from KoreaMolecular Analysis of Korean Anzia opuntiella (Lichenized Ascomycota) Based on...
- Published
- 2006
11. Comparison of cell wall ultrastructures ofaspergillus nidulansin presence and absence of a MnpAp mannoprotein
- Author
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Sung Soo Whang, Hyo‐Yong Jeong, and Keon-Sang Chae
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Cell wall ,Cell type ,biology ,Hypha ,Aspergillus nidulans ,Ultrastructure ,Wild type ,Immunogold labelling ,biology.organism_classification ,Hyphal cell wall ,Cell biology - Abstract
The ultrastructure of Aspergillus nidulans cell wall in relation to a mannoprotein was studied by scanning and transmission electron microscopy. An mnpAp null‐mutant, DMPV1, was used as a negative control of a wild type VER7. To analyze whether the mannoprotein in the cell wall during the development of an mnpAp null‐mutant is present or not, immunogold microscopy was also adopted. The surface sculpturing of various cell types ‐ hyphae, conidium, Hulle cell, and ascospore ‐ were not very different between the wild type and the mnpAp‐null mutant (DMPV1) as examined by scanning electron microscopy. These results were comparable to those examined by transmission electron microscopy, in that the hyphal cell wall was not indentical between two strains, probably caused by the MnpA protein (MnpAp). MnpAp was absent in both the hyphal cell wall of the DMPV1 strain and the conidial cell wall of a wide type, but clearly recognized in the hyphal cell wall of a wild type.
- Published
- 2006
12. The GanB Gα-Protein Negatively Regulates Asexual Sporulation and Plays a Positive Role in Conidial Germination in Aspergillus nidulansSequence data from this article have been deposited with the EMBL/GenBank Data Libraries under accession no. AF198116
- Author
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Kwang-Yeop Jahng, Keon-Sang Chae, Mi-Hee Chang, and Dong-Min Han
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Hyphal growth ,Genetics ,biology ,Aspergillus nidulans ,Germination ,Mutant ,Conidiation ,Asexual sporulation ,biology.organism_classification ,Gene ,Conidium - Abstract
We isolated the ganB gene encoding the Gα-protein homolog from Aspergillus nidulans. To investigate the cellular function of GanB, various mutant strains were isolated. Deletion of constitutively inactive ganB mutants showed conidiation and derepressed brlA expression in a submerged culture. Constitutive activation of GanB caused a reduction in hyphal growth and a severe defect in asexual sporulation. We therefore propose that GanB may negatively regulate asexual sporulation through the BrlA pathway. In addition, deletion or constitutive inactivation of GanB reduced germination rate while constitutive activation led to precocious germination. Furthermore, conidia of a constitutively active mutant could germinate even without carbon source. Taken together, these results indicated that GanB plays a positive role during germination, possibly through carbon source sensing, and negatively regulates asexual conidiation in A. nidulans.
- Published
- 2004
13. Presence of a mannoprotein, MnpAp, in the hyphal cell wall ofAspergillus nidulans
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Sung Soo Whang, Hyo-Young Jeong, and Keon-Sang Chae
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0106 biological sciences ,0301 basic medicine ,Cell type ,biology ,Physiology ,Immunoelectron microscopy ,Mutant ,Wild type ,Cell Biology ,General Medicine ,Immunogold labelling ,030108 mycology & parasitology ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Microbiology ,Cell biology ,Cell wall ,03 medical and health sciences ,Aspergillus nidulans ,Genetics ,Molecular Biology ,Hyphal cell wall ,Ecology, Evolution, Behavior and Systematics - Abstract
The presence of a mannoprotein, MnpAp, in the hyphal cell wall of Aspergillus nidulans was examined by immunogold electron microscopy using a mnpA-null mutant as a negative control. The hyphal cell wall of wild type consisted of two layers-an electron-dense smooth outer layer and an electron-translucent inner layer-while the hyphal cell wall of the mnpA-null mutant had an electron-dense irregular outer layer together with the electron-translucent inner layer. In wild type, MnpAp was present throughout the electron-translucent layer of the hyphal cell wall but was absent from the conidial cell wall. In the mnpA-null mutant, MnpAp was absent from the cell walls of both cell types. These results indicate that MnpAp is present in the hyphal cell wall and that it influences cell wall surface structure.
- Published
- 2004
14. Increased expression of O-acetyl disialoganglioside synthase during rat liver fibrogenesis relates to stellate cell activation
- Author
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Keon-Sang Chae, Jeong-Yong Choi, Geom Seog Seo, Hong Kuk Kim, Young Nyun Park, Sung Hee Lee, Dong Hwan Sohn, and Pil-Hoon Park
- Subjects
Adult ,Liver Cirrhosis ,Male ,Cirrhosis ,Biophysics ,Gene Expression ,In situ hybridization ,Biology ,Biochemistry ,Rats, Sprague-Dawley ,Downregulation and upregulation ,Western blot ,medicine ,Animals ,Humans ,RNA, Messenger ,Molecular Biology ,Cells, Cultured ,medicine.diagnostic_test ,ATP synthase ,cDNA library ,Cell Biology ,medicine.disease ,Immunohistochemistry ,Molecular biology ,Sialyltransferases ,Rats ,Disease Models, Animal ,Child, Preschool ,Hepatic stellate cell ,biology.protein ,Female - Abstract
The activation of the hepatic stellate cell (HSC) is a key step in liver fibrogenesis. Utilizing large scale sequencing of a 3'-directed cDNA library, we investigated expression profiles of quiescent and activated rat HSCs. During the activation process, O-acetyl disialoganglioside synthase (OAcGD3S) was identified as one of the significant upregulated factors. Upregulation of OAcGD3S in cultured HSCs was confirmed by both Northern and Western blot analyses. OAcGD3S expression in models of experimental liver fibrosis was investigated at the mRNA level using RT-PCR. The expression of OAcGD3S protein in activated rat HSCs and in experimental fibrotic livers was demonstrated by immunohistochemistry. In situ hybridization revealed OAcGD3S mRNA expression in areas of ductular proliferation. Furthermore, O-acetyl GD3 protein was detected in activated rat HSCs and human cirrhosis livers. This study shows that OAcGD3S is strongly expressed during liver fibrogenesis and HSCs seem to be the major cellular sources of OAcGD3S in the liver.
- Published
- 2003
15. [Untitled]
- Author
-
Seockyu Park, Heeun Kim, Tai-Boong Uhm, Keon-Sang Chae, Yeonsoo Han, and Songyi Song
- Subjects
Biochemistry ,Conserved motif ,Tryptophan ,Wild type ,biology.protein ,Bioorganic chemistry ,General Medicine ,Glutamic acid ,Motif (music) ,Aspergillus ficuum ,Biology ,Enzyme assay - Abstract
The importance of the WMN(D/E)PN motif, which is well conserved among β-fructofuranosidases grouped in the glycosylhydrolase family 32, in Aspergillus ficuum endoinulinase was accessed. Each mutant enzyme generated by site-directed mutagenesis of Trp17 in the conserved motif to Gln, Leu, Ser, Pro, Thr, or Met had an activity of less than 1% of the wild type. Another mutant enzyme obtained by mutation of Glu20 in the motif to Ser, Leu, Thr, Gln, Ala, or Val had an enzyme activity of less than 1% of the wild type. Furthermore, the E20D mutant enzyme, in which Glu20 in the conserved motif was replaced with Asp, had 1.1% of the wild type activity. These results clearly indicated that Trp17 and Glu20 are essential for the enzyme activity.
- Published
- 2003
16. The veA gene is necessary for the inducible expression by fructosyl amines of the Aspergillus nidulans faoA gene encoding fructosyl amino acid oxidase (amadoriase, EC 1.5.3)
- Author
-
Hyo-Young Jeong, Myung Hoon Song, Vincent M. Monnier, Kwang-Yeop Jahng, Xinle Wu, Keon-Sang Chae, Jung Ho Back, and Dong-Min Han
- Subjects
Molecular Sequence Data ,Mutant ,Fructose ,Biochemistry ,Microbiology ,Aspergillus nidulans ,Gene Expression Regulation, Enzymologic ,Gene Expression Regulation, Fungal ,Complementary DNA ,Gene expression ,Genetics ,Amino Acid Sequence ,Molecular Biology ,Gene ,Propylamines ,Sequence Homology, Amino Acid ,biology ,Reverse Transcriptase Polymerase Chain Reaction ,Activator (genetics) ,Intron ,Nucleic acid sequence ,General Medicine ,biology.organism_classification ,Molecular biology ,Blotting, Southern ,Enzyme Induction ,Amino Acid Oxidoreductases - Abstract
The faoA gene encoding fructosyl amino acid oxidase (FAOD, EC 1.5.3) was isolated from Aspergillus nidulans and characterized. The complete nucleotide sequence of the faoA (fructosyl amino acid oxidase) gene and its cDNA revealed that the faoA gene encodes a 441-amino-acid polypeptide interrupted by five introns. Expression of the A. nidulans faoA gene was inducible by fructosyl propylamine and fructosyl lysine, as is the case for the gene encoding FAOD in other organisms. The faoA gene was not induced by these fructosyl amines in a null mutant of the veA gene, which has been identified as an activator of sexual development and as an inhibitor of asexual development; the faoA gene was induced greatly in a veA(+) wild-type. However, veA gene expression was not affected by fructosyl amines. Even in the absence of fructosyl propylamine, synthesis of the faoA transcript was higher in the veA(+) background than in a veA-null mutation background. These results indicated that faoA gene expression is inducible by fructosyl amines and by the veA gene, and that the veA gene is necessary for full induction of faoA gene expression by fructosyl amines. Thus, the faoA gene is the first gene whose expression is dependent on the veA gene. Furthermore, the faoA gene, present in a single copy, seems to be dispensable for development and growth, since the faoA-null mutant grew normally and developed as many conidia and sexual structures as the wild-type.
- Published
- 2002
17. [Untitled]
- Author
-
Myung Hoon Song, K. Swaminathan, K. Selvam, and Keon-Sang Chae
- Subjects
biology ,Physiology ,Chemical oxygen demand ,Pilot scale ,General Medicine ,biology.organism_classification ,Pulp and paper industry ,Applied Microbiology and Biotechnology ,Chloride ,Wastewater ,medicine ,Fomes ,Effluent ,Incubation ,Biotechnology ,Trametes versicolor ,medicine.drug - Abstract
White rot fungi Fomes lividus and Trametes versicolor, isolated from the Western Ghats region of Tamil Nadu, India, were used to treat pulp and paper industry effluents on a laboratory scale and in a pilot scale. On the laboratory scale a maximum decolourization of 63.9% was achieved by T. versicolor on the fourth day. Inorganic chloride at a concentration of 765 mg/l, which corresponded to 227% of that in the untreated effluent, was liberated by F. lividus on the 10th day. The chemical oxygen demand (COD) was also reduced to 1984 mg/l (59.3%) by each of the two fungi. On the pilot scale, a maximum decolourization of 68% was obtained with the 6-day incubation by T. versicolor, inorganic chloride 475 mg/l (103%) was liberated on the seventh day by T. versicolor, and the COD was reduced to 1984 mg/l corresponding to 59.32% by F. lividus. These results suggested that F. lividus seems to be another candidate efficient for dechlorination of wastewater.
- Published
- 2002
18. The nsdD gene encodes a putative GATA-type transcription factor necessary for sexual development of Aspergillus nidulans
- Author
-
Jae-Hyuk Yu, Kap-Hoon Han, Kyu-Yong Han, Dong-Min Han, Kwang-Yeop Jahng, and Keon-Sang Chae
- Subjects
Genetics ,Complementation ,Zinc finger ,biology ,Aspergillus nidulans ,Mutant ,Asexual sporulation ,biology.organism_classification ,Molecular Biology ,Microbiology ,Gene ,Transcription factor ,Sexual reproduction - Abstract
The ability to reproduce both sexually and asexually is one of the characteristics of the homothalic ascomycete Aspergillus nidulans. Unlike the other Aspergillus species, A. nidulans undergoes sexual development that seems to be regulated by internal and external stimuli. To begin to understand the sexual reproduction of A. nidulans we previously isolated and characterized several NSD (never in sexual development) mutants that failed to produce any sexual reproductive organs, and identified four complementation groups, nsdA, nsdB, nsdC, and nsdD. The nsdD gene has been isolated, and it is predicted to encode a GATA-type transcription factor with the type IVb zinc finger DNA-binding domain. The mRNA of the nsdD gene started to accumulate in the early phase of vegetative growth, and the level increased as sexual development proceeded. However, it decreased during asexual sporulation and no nsdD mRNA was detected in conidia. Deletion of nsdD resulted in no cleistothecia (fruiting bodies) formation, even under the conditions that preferentially promoted sexual development, indicating that nsdD is necessary for sexual development. In contrast, when the nsdD gene was over-expressed, sexual-specific organ (Hulle cell) was formed even in submerged culture, which normally completely blocked sexual development, and the number of cleistothecia was also dramatically increased on solid medium. These results lead us to propose that the nsdD gene functions in activating sexual development of A. nidulans. Multiple copies of the nsdD gene could suppress nsdB5 and veA1, indicating that either nsdD acts downstream of these genes or possibly functions in overlapping pathway(s).
- Published
- 2001
19. Enhanced production of Aspergillus ficuum endoinulinase in Saccharomyces cerevisiae by using the SUC2-deletion mutation
- Author
-
Hee-Seo Kim, Hyo-Young Jeong, Moon-Sik Yang, Seockyu Park, and Keon-Sang Chae
- Subjects
chemistry.chemical_classification ,biology ,Saccharomyces cerevisiae ,Mutant ,Bioengineering ,Fructose ,biology.organism_classification ,Applied Microbiology and Biotechnology ,Biochemistry ,Yeast ,chemistry.chemical_compound ,Invertase ,Enzyme ,chemistry ,Kluyveromyces marxianus ,Inulinase ,Biotechnology - Abstract
The inuB gene, encoding an Aspergillus ficuum endoinulinase, was expressed by the Kluyveromyces marxianus INU1 promoter in Saccharomyces cerevisiae to produce an enzyme free of an exoinulinase and an extracellular invertase. The recombinant yeast strain produced the enzyme at the concentration of 83.0 U/ml with 2% glucose as a carbon source and 2% fructose as an inducer added after 12 h of initiation of culture. Two Δsuc2 mutants produced higher amounts of the enzyme by 13–49 U/ml than SUC2 wild types. The molecular weight of the secreted enzyme was 67 kDa as measured by SDS-PAGE and Western blot analysis, which was larger by 1–3 kDa than those of the purified enzymes. The purified enzyme has been reported to be a mixture of two polypeptides of 64 kDa and 66 kDa in molecular weight.
- Published
- 2001
20. Enhanced Iron Uptake of Saccharomyces cerevisiae by Heterologous Expression of a Tadpole Ferritin Gene
- Author
-
Young-Mi Shin, Tae-Ho Kwon, Keon-Sang Chae, Moon-Sik Yang, Jae-Ho Kim, Dae-Hyuk Kim, and Kyung-Suk Kim
- Subjects
Iron ,Saccharomyces cerevisiae ,Applied Microbiology and Biotechnology ,law.invention ,Transformation, Genetic ,Shuttle vector ,law ,Animals ,Northern blot ,Ecology ,biology ,Spectrophotometry, Atomic ,Blotting, Northern ,Physiology and Biotechnology ,biology.organism_classification ,Recombinant Proteins ,Yeast ,Ferritin ,Biochemistry ,Larva ,Ferritins ,biology.protein ,Recombinant DNA ,Ferritin complex ,Heterologous expression ,Food Science ,Biotechnology - Abstract
We genetically engineered Saccharomyces cerevisiae to express ferritin, a ubiquitous iron storage protein, with the major heavy-chain subunit of tadpole ferritin. A 450-kDa ferritin complex can store up to 4,500 iron atoms in its central cavity. We cloned the tadpole ferritin heavy-chain gene (TFH) into the yeast shuttle vector YEp352 under the control of a hybrid alcohol dehydrogenase II and glyceraldehyde-3-phosphate dehydrogenase promoter. We confirmed transformation and expression by Northern blot analysis of the recombinant yeast, by Western blot analysis using an antibody against Escherichia coli -expressed TFH, and with Prussian blue staining that indicated that the yeast-expressed tadpole ferritin was assembled into a complex that could bind iron. The recombinant yeast was more iron tolerant in that 95% of transformed cells, but none of the recipient strain cells, could form colonies on plates containing 30 mM ferric citrate. The cell-associated concentration of iron was 500 μg per gram (dry cell weight) of the recombinant yeast but was 210 μg per gram (dry cell weight) in the wild type. These findings indicate that the iron-carrying capacity of yeast is improved by heterologous expression of tadpole ferritin and suggests that this approach may help relieve dietary iron deficiencies in domesticated animals by the use of the engineered yeast as a feed and food supplement.
- Published
- 2001
21. Simple identification of veA1 mutation in Aspergillus nidulans
- Author
-
Dong-Min Han, Kap-Hoon Han, Keon Sang Chae, and Jae-Sin Park
- Subjects
Homothallism ,Genes, Fungal ,medicine.disease_cause ,Polymerase Chain Reaction ,Applied Microbiology and Biotechnology ,Microbiology ,Aspergillus nidulans ,DNA sequencing ,law.invention ,law ,medicine ,Allele ,DNA, Fungal ,Deoxyribonucleases, Type II Site-Specific ,Gene ,Polymerase chain reaction ,Sequence Deletion ,Genetics ,Mutation ,biology ,Oxalic Acid ,General Medicine ,biology.organism_classification ,Phenotype ,Polymorphism, Restriction Fragment Length - Abstract
The veA gene plays an important role in development of a homothallic filamentous fungus Aspergillus nidulans. The veA1 phenotype can be difficult to distinguish from the wild-type veA. Despite the importance of the veA allele, no efficient identification method has been reported besides DNA sequencing. Here, we present simple physiological and molecular biological ways to distinguish between the veA wild-type and veA1 allele. The novel approaches, which involve incubation in the presence of oxalic acid, polymerase chain reaction using double mismatched primers, and BstXI enzyme digestion, are simpler, faster and more cost-efficient than genome sequencing.
- Published
- 2010
22. The rpl16a Gene for Ribosomal Protein L16A Identified from Expressed Sequence Tags Is Differentially Expressed during Sexual Development of Aspergillus nidulans
- Author
-
Kwang-Yeop Jahng, Keon-Sang Chae, Hyo-Young Jeong, and Dong Min Han
- Subjects
Ribosomal Proteins ,Leucine zipper ,Saccharomyces cerevisiae Proteins ,Genes, Fungal ,Molecular Sequence Data ,Microbiology ,Aspergillus nidulans ,Fungal Proteins ,Ribosomal protein ,Gene Expression Regulation, Fungal ,Complementary DNA ,Genetics ,Amino Acid Sequence ,Northern blot ,Gene ,Gene Library ,Expressed Sequence Tags ,Expressed sequence tag ,Base Sequence ,biology ,Sequence Analysis, DNA ,biology.organism_classification ,Molecular biology ,GenBank - Abstract
We obtained 305 expressed sequence tags (ESTs), which are from the poly(A) site to the most proximal MboI site, from mycelia at the early sexual developmental (ESD) stage of Aspergillus nidulans. By comparison of these ESTs with those obtained previously from the vegetative stage and from the late sexual developmental stage followed by Northern blot analyses, genes of 17 ESTs were identified as being expressed more abundantly at the ESD stage than at the vegetative stage. Five of 17 genes were expressed more abundantly in the presence of the veA gene or the nsdD gene, suggesting that these 5 genes may be involved in sexual development. In a gene of one EST, appearing three times among 305 ESTs and identified by GenBank, polyadenylation seemed to occur at two sites. Nucleotide sequences of the gene having the EST and its cDNA revealed that the gene can code for a 202-amino-acid polypeptide with an estimated molecular mass of 23 kDa. The deduced amino acid showed 73% identity to Saccharomyces cerevisiae ribosomal protein L16A (RPL16A), and therefore the gene was named rpl16a. A. nidulans RPL16A had a putative leucine zipper motif and a basic leucine zipper motif like those of other organisms. The expression level of the rpl16a gene, present as a single copy in this organism, reached a maximum after 2 h, decreased thereafter, and increased again 30 to 50 h after the end of induction of sexual development. These results clearly indicated that the rpl16a gene is expressed differentially during sexual development.
- Published
- 2000
23. [Untitled]
- Author
-
Dong Whan Lee, Keon-Sang Chae, Jeong-Yong Choi, Jeong-Shin Koh, Jong-Hwa Kim, and Moon-Sik Yang
- Subjects
Genetics ,Expressed sequence tag ,biology ,cDNA library ,Aspergillus niger ,Nucleic acid sequence ,Bioengineering ,General Medicine ,biology.organism_classification ,Applied Microbiology and Biotechnology ,Homology (biology) ,Complementary DNA ,GenBank ,Gene ,Biotechnology - Abstract
Determined sequences of 285 randomly selected clones in a 3′-directed cDNA library of Aspergillus niger could identify expressed seqeunce tags (ESTs) of genes highly expressed. One EST appeared seven times, one six times, one five times, four three times and 12 twice. Out of these 19 ESTs, ten were identified in GenBank, but none was of A. niger, suggesting that there are a lot of unidentified genes highly expressed in A. niger.
- Published
- 1999
24. Cloning and Nucleotide Sequence of the Endoinulinase-Encoding Gene, inu2, from Aspergillus ficuum
- Author
-
Hee-Seo Kim, Jean-Pol Cassart, Keon-Sang Chae, Dongwon Lee, Tai-Boong Uhm, and Jean Vandenhaute
- Subjects
Genetics ,biology ,Penicillium purpurogenum ,Nucleic acid sequence ,Bioengineering ,Sequence alignment ,General Medicine ,Molecular cloning ,biology.organism_classification ,Applied Microbiology and Biotechnology ,Homology (biology) ,Open reading frame ,Biochemistry ,Gene ,Peptide sequence ,Biotechnology - Abstract
A 2.3 kb DNA fragment that contains a gene encoding endoinulinase, inu2, from Aspergillus ficuum ATCC 16882 was isolated and analyzed. It includes an open reading frame of 1,551 bp, coding for a polypeptide with calculated molecular weight of 55,790 Da, including a putative signal peptide of 22 amino acids. Alignment of amino acid sequences revealed 73.3% identity and 93.9% similarity between A. ficuum and Penicillium purpurogenum endoinulinase.
- Published
- 1998
25. Quantitative analysis of gene expression in sexual structures of Aspergillus nidulans by sequencing of 3′-directed cDNA clones
- Author
-
Seung Hwan Lee, Hyun-A Hwang, Dong Whan Lee, Keon-Sang Chae, and Jong Hwa Kim
- Subjects
Genetics ,Expressed sequence tag ,biology ,cDNA library ,food and beverages ,biology.organism_classification ,Microbiology ,Aspergillus nidulans ,GenBank ,Complementary DNA ,Gene expression ,Northern blot ,Molecular Biology ,Gene - Abstract
We constructed a 3′-directed cDNA library of cleistothecia and Hulle cells of Aspergillus nidulans to examine gene expression patterns of the sexual structures and to have probes necessary to isolate sexual structure-specific genes. Sequencing of 360 randomly selected cDNA clones yielded 272 expressed sequence tags (ESTs), most of which probably represent frequently or less expressed genes in sexual structures of A. nidulans. Among the 272 ESTs, 33 ESTs (87 cDNA clones) appeared more than once and 2 ESTs appeared 6 times; 9 ESTs matched GenBank entries. When compared with sequences obtained from a mycelial 3′-directed cDNA library of A. nidulans, 28 out of 33 ESTs seem to be sexual structure-specific. Northern blot analyses of 20 ESTs showed that 17 are sexual structure-specific. The remaining three ESTs also hybridized with RNA isolated from vegetative mycelia. These results suggest that analyses of ESTs from different cell types or tissues can readily demonstrate gene expression patterns of specific cell types and identify cell type-specific cDNA probes.
- Published
- 1996
26. [Untitled]
- Author
-
K. Selvam, K. Swaminathan, and Keon-Sang Chae
- Subjects
biology ,Physiology ,General Medicine ,biology.organism_classification ,Pulp and paper industry ,Applied Microbiology and Biotechnology ,Congo red ,chemistry.chemical_compound ,Amido black 10B ,Adsorption ,Metabolic breakdown ,chemistry ,Botany ,Fomes ,Orange G ,Effluent ,Mycelium ,Biotechnology - Abstract
The white rot fungus, Fomes lividus, was isolated from the logs of Shorea robusta in the Western Ghats region of Tamil Nadu, India. The fungus was tested for decolorization of azo dyes such as orange G (50 μM) congo red (50 μM) amido black 10B (25 μM) and also for colour removal from dye industry effluents. The results revealed that the fungus could remove only 30.8% of orange G in the synthetic solution, whereas congo red and amido black 10B were removed by 74.0 and 98.9% respectively. A dye industry effluent was treated by the fungus in batch and continuous mode. In batch mode treatment, a maximum decolorization of 84.4% was achieved on day 4, and in continuous mode a maximum decolorization of 37.5% was obtained on day 5. The colour removal by the basidiomycete fungus might be due to adsorption of the dyes to the mycelial surface and metabolic breakdown. These results suggested that the batch mode treatment of Fomes lividus is one of the most efficient ways for colour removal in dye industry effluents.
- Published
- 2003
27. The use of overlapping and tailed short primers in the chromosomal assignment of short cDNAs by the polymerase chain reaction
- Author
-
Kousaku Okubo, Kenichi Matsubara, Katsuji Murakawa, and Keon-Sang Chae
- Subjects
DNA, Complementary ,Molecular Sequence Data ,Biology ,Site specificity ,Polymerase Chain Reaction ,Lower limit ,law.invention ,law ,Complementary DNA ,Genetics ,Animals ,Humans ,Nucleotide ,Cloning, Molecular ,Polymerase chain reaction ,DNA Primers ,chemistry.chemical_classification ,Base Sequence ,Chromosome Mapping ,Chromosome ,DNA ,General Medicine ,Molecular biology ,Chain length ,chemistry ,Nucleic Acid Conformation ,Thermodynamics ,Primer (molecular biology) - Abstract
For the PCR-based chromosomal assignment of very short cDNA fragments specifically designed primers are required. We tested primers with very short core sequences that are identical or complementary to known cDNA sequences, with or without tails at the 5' ends. The lower limit of the core length for PCR using human chromosome templates was 14 nucleotides (nt) when they have tails. The minimal length of the tail was 2 nt when it was attached to the 5' end of a 14-nt core. In the absence of a tail, 15 nt are needed for the core to act properly. The overall size of the short cDNA fragments that could be assigned was further reduced by using a pair of primers that overlap at the 3' ends. The limits of the free energy of overlap were about -1.9 kcal/mol at 45 degrees C, -2.9 kcal/mol at 50 degrees C and -4.5 kcal/mol at 55 degrees C. A combination of these features in a primer pair allowed cDNA fragments as short as 30 nt to be assigned.
- Published
- 1994
28. Chromosomal Assignment of Short cDNA Sequences by PCR Using Overlapping and Tailed Short Primers
- Author
-
Katsuji Murakawa, Kenichi Matsubara, Keon-Sang Chae, and Kousaku Okubo
- Subjects
chemistry.chemical_classification ,Genetics ,DNA, Complementary ,Base Sequence ,Molecular Sequence Data ,Chromosome Mapping ,General Medicine ,Hybrid Cells ,Biology ,Polymerase Chain Reaction ,Cricetulus ,chemistry ,Cricetinae ,GenBank ,Complementary DNA ,Animals ,Humans ,Nucleotide ,Molecular Biology ,DNA Primers - Abstract
Overlapping primers and tailed short primers are effective agents for mapping very short cDNA sequences. By using such primers, human cDNAs as short as 32 nucleotides in length can produce PCR bands. Using these and other primers of ordinary size, 44 cDNAs were assigned to chromosomes, of which 24 were assigned to single chromosomes, and 2 were assigned to two chromosomes and two were assigned to three chromosomes, respectively. Among the 24 cDNAs, all of which matched GenBank entries, 6 cDNAs were observed to map to the same chromosomes as reported previously.
- Published
- 1994
29. [Untitled]
- Author
-
Keon-Sang Chae, Dong Min Han, Myung Hoon Song, Ju-young Nah, and Yeon Soo Han
- Subjects
chemistry.chemical_classification ,biology ,Potassium ,food and beverages ,Salt (chemistry) ,Conidiation ,chemistry.chemical_element ,Bioengineering ,General Medicine ,Fungi imperfecti ,biology.organism_classification ,Applied Microbiology and Biotechnology ,Conidium ,Horticulture ,chemistry ,Aspergillus oryzae ,Botany ,Biotechnology - Abstract
Addition of KCl to medium at 0.1 M or higher promoted the formation of conidial heads in Aspergillus oryzae. When higher concentrations of KCl were added, a larger number of conidial heads were formed. NaCl and MgCl2 were slightly less effective than KCl. The effect of salt on the formation of conidial heads on a minimal medium was as high as on a potato/dextrose medium but slightly higher than that on a complex medium when 1 M KCl was added.
- Published
- 2001
30. Presence of a mannoprotein, MnpAp, in the hyphal cell wall of Aspergillus nidulans
- Author
-
Hyo-Young Jeong, Keon-Sang Chae, and Sung Soo Whang
- Subjects
Physiology ,Genetics ,Cell Biology ,General Medicine ,Molecular Biology ,Ecology, Evolution, Behavior and Systematics - Abstract
The presence of a mannoprotein, MnpAp, in the hyphal cell wall of Aspergillus nidulans was examined by immunogold electron microscopy using a mnpA-null mutant as a negative control. The hyphal cell wall of wild type consisted of two layers-an electron-dense smooth outer layer and an electron-translucent inner layer-while the hyphal cell wall of the mnpA-null mutant had an electron-dense irregular outer layer together with the electron-translucent inner layer. In wild type, MnpAp was present throughout the electron-translucent layer of the hyphal cell wall but was absent from the conidial cell wall. In the mnpA-null mutant, MnpAp was absent from the cell walls of both cell types. These results indicate that MnpAp is present in the hyphal cell wall and that it influences cell wall surface structure.
- Published
- 2010
31. [Untitled]
- Author
-
Tai-Boong Uhm, Moon-Sik Yang, Jungbae Kim, Dong Whan Lee, Hee-Seo Kim, Eun Ja Ryu, and Keon-Sang Chae
- Subjects
biology ,Saccharomyces cerevisiae ,Inulin ,Bioengineering ,General Medicine ,biology.organism_classification ,Applied Microbiology and Biotechnology ,Yeast ,Microbiology ,chemistry.chemical_compound ,Invertase ,Kluyveromyces marxianus ,chemistry ,Biochemistry ,Gene expression ,Inulinase ,Gene ,Biotechnology - Abstract
The INU2 gene encoding an endoinulinase of Aspergillus ficuum was expressed by the Kluyveromyces marxianus INU1 promoter in a SUC2-deleted Saccharomyces cerevisiae to produce the endoinulinase preparation free of an exoinulinase and an extracellular invertase in the culture medium. A recombinant yeast strain produced the sufficient amount of the enzyme to make a halo around its colony, when inulin was included in the medium.
- Published
- 1999
32. Predicting the chemical composition and structure of Aspergillus nidulans hyphal wall surface by atomic force microscopy
- Author
-
Kwang-Yeop Jahng, Keon-Sang Chae, Hyun-uk Lee, Dong-Min Han, Haeseong Lee, and Jong Bae Park
- Subjects
beta-Glucans ,Hypha ,Hyphal tip ,Hyphae ,Chitin ,macromolecular substances ,Microscopy, Atomic Force ,Applied Microbiology and Biotechnology ,Microbiology ,Aspergillus nidulans ,Cell wall ,chemistry.chemical_compound ,Cell Wall ,Chemical composition ,Glucan ,chemistry.chemical_classification ,biology ,Chemistry ,fungi ,Proteins ,General Medicine ,Adhesion ,biology.organism_classification ,carbohydrates (lipids) ,Biophysics ,Protein Binding - Abstract
In fungi, cell wall plays an important role in growth and development. Major macromolecular constituents of the aspergilli cell wall are glucan, chitin, and protein. We examined the chemical composition and structure of the Aspergillus nidulans hyphal wall surface by an atomic force microscope (AFM). To determine the composition of the cell wall surface, the adhesion forces of commercially available beta-glucan, chitin, and various proteins were compared to those of corresponding fractions prepared from the hyphal wall. In both setups, the adhesion forces of beta-glucan, chitin, and protein were 25-50, 1000-3000, and 125-300 nN, respectively. Adhesion force analysis demonstrated that the cell surface of the apical tip region might contain primarily chitin and beta-glucan and relatively a little protein. This analysis also showed the chemical composition of the hyphal surface of the mid-region would be different from that of the apical region. Morphological images obtained by the tapping mode of AFM revealed that the hyphal tip surface has moderate roughness.
- Published
- 2008
33. Sexual Development in Aspergillus nidulans
- Author
-
Kap-Hoon Han, Dong-Min Han, and Keon-Sang Chae
- Subjects
biology ,Aspergillus nidulans ,biology.organism_classification ,Microbiology - Published
- 2007
34. The Aspergillus nidulans esdC (early sexual development) gene is necessary for sexual development and is controlled by veA and a heterotrimeric G protein
- Author
-
Dong-Min Han, Kap-Hoon Han, Sung-Suk Lee, Jong-Hwa Kim, Hosun Moon, Kwang-Yeop Jahng, Keon-Sang Chae, and Serha Kim
- Subjects
Mutant ,Molecular Sequence Data ,medicine.disease_cause ,Microbiology ,Aspergillus nidulans ,Fungal Proteins ,Gene Expression Regulation, Fungal ,Genetics ,medicine ,Amino Acid Sequence ,Peptide sequence ,Gene ,Regulation of gene expression ,Mutation ,Glycogen binding ,Binding Sites ,biology ,Sequence Homology, Amino Acid ,fungi ,Wild type ,Gene Expression Regulation, Developmental ,biology.organism_classification ,Heterotrimeric GTP-Binding Proteins ,Introns - Abstract
The esdC (early sexual development) gene was isolated by using an expressed sequence tag (EST) as a probe from a genomic library of the early sexual developmental stage mycelia of Aspergillus nidulans. The sequence analysis revealed that the esdC gene contains a 59bp intron and encodes a 266 amino acid polypeptide with a calculated molecular weight of 29.4kDa. The EsdC protein is conserved among filamentous fungi and has a domain with similarity to a glycogen binding domain conserved in the beta subunit of the AMP-activated protein kinase (AMPK) complex. Although the esdD gene was expressed during asexual development, the expression reached its maximum at 10h and decreased thereafter up to 50h after the end of the induction of sexual development. In an esdC-null mutant under a veA(+) background, no sexual structures were formed at any condition examined. However, esdC overexpression did not lead to an induction of sexual development. In addition, to the effect of the esdC mutation on the sexual development, more conidiophores were formed in the esdC-null mutant than in a wild type. These results indicate that the esdC gene is necessary for sexual structure formation but its overexpression is not sufficient to enhance this process. Expression of the esdC gene throughout development was positively regulated by the veA gene. In addition, very little and no esdC transcript, respectively, was observed in an flbA-null mutant and in a fadA(G42R) mutant, and the esdC transcript level was higher in a fadA-null mutant and in a sfaD-null mutant than in a wild type, indicating that inactivation of FadA is necessary for positive regulation of esdC expression.
- Published
- 2007
35. Identification of expressed sequence tags of genes expressed highly in the activated hepatic stellate cell
- Author
-
Sung Hee Lee, Dong Hwan Sohn, and Keon-Sang Chae
- Subjects
Expressed Sequence Tags ,Cell type ,Expressed sequence tag ,cDNA library ,Gene Expression Profiling ,Organic Chemistry ,food and beverages ,RNA ,Biology ,Molecular biology ,Rats ,Rats, Sprague-Dawley ,Gene expression profiling ,Liver ,Drug Discovery ,Hepatic stellate cell ,Animals ,Molecular Medicine ,Genomic library ,Gene ,Gene Library - Abstract
Expressed sequence tags (ESTs) were generated from two 3'-directed cDNA libraries constructed from quiescent and activated rat hepatic stellate cell (HSC) to analyze the expression profiles of active genes in both cells. From quiescent and activated HSC, 694 ESTs and 779 ESTs, respectively, were obtained after excluding those having shorter than 30 bp. Among ESTs obtained from quiescent and activated HSC, 68 and 73 kinds of ESTs (186 clones and 236 clones), respectively, appeared more than once, implying that their genes are expressed highly in each cell type. 52 among 73 ESTs appeared only in the activated HSC, 47 among 68 ESTs only in the normal HSC, and 21 in both cells. The genes of these 52 ESTs were assumed to be expressed more highly in the activated HSC. To confirm the high expression of genes of which the ESTs appeared more than twice in the activated HSC, northern hybridization was carried out with RNAs derived from rat normal and fibrotic liver using each of 18 EST DNAs as probe. 13 ESTs showed more intense bands with RNA isolated from the fibrotic liver than normal liver. From these results, we confirm the positive correlation between abundance of transcript in activated HSCs and the expression level in fibrotic liver. The expression profile of the transcripts serves as an important tool in understanding the biological properties of HSC.
- Published
- 2004
36. Trp17 and Glu20 residues in conserved WMN(D/E)PN motif are essential for Aspergillus ficuum endoinulinase (EC 3.2.1.7) activity
- Author
-
Seockyu, Park, Yeonsoo, Han, Heeun, Kim, Songyi, Song, Tai-Boong, Uhm, and Keon-Sang, Chae
- Subjects
Aspergillus ,Amino Acid Substitution ,Glycoside Hydrolases ,Amino Acid Motifs ,Mutagenesis, Site-Directed ,Tryptophan ,Glutamic Acid ,Amino Acid Sequence ,Saccharomyces cerevisiae ,Conserved Sequence ,Recombinant Proteins ,DNA Primers - Abstract
The importance of the WMN(D/E)PN motif, which is well conserved among beta-fructofuranosidases grouped in the glycosylhydrolase family 32, in Aspergillus ficuum endoinulinase was accessed. Each mutant enzyme generated by site-directed mutagenesis of Trp17 in the conserved motif to Gln, Leu, Ser, Pro, Thr, or Met had an activity of less than 1% of the wild type. Another mutant enzyme obtained by mutation of Glu20 in the motif to Ser, Leu, Thr, Gln, Ala, or Val had an enzyme activity of less than 1% of the wild type. Furthermore, the E20D mutant enzyme, in which Glu20 in the conserved motif was replaced with Asp, had 1.1% of the wild type activity. These results clearly indicated that Trp17 and Glu20 are essential for the enzyme activity.
- Published
- 2003
37. Expression of the mnpA gene that encodes the mannoprotein of Aspergillus nidulans is dependent on fadA and flbA as well as veA
- Author
-
Kwang-Yeop Jahng, Keon-Sang Chae, Heeun Kim, Hyo-Young Jeong, and Dong-Min Han
- Subjects
Expressed Sequence Tags ,Fungal protein ,Expressed sequence tag ,Membrane Glycoproteins ,biology ,cDNA library ,fungi ,Mutant ,Sequence Analysis, DNA ,biology.organism_classification ,Microbiology ,Molecular biology ,Heterotrimeric GTP-Binding Proteins ,Aspergillus nidulans ,Fungal Proteins ,genomic DNA ,GTP-Binding Proteins ,Complementary DNA ,Genetics ,Gene - Abstract
The single copy mnpA gene that encodes a mannoprotein of Aspergillus nidulans and its cDNA were isolated from the genomic and cDNA libraries, respectively. The determined nucleotide sequences of the genomic DNA and its cDNA revealed that the gene has an open-reading frame of 261 amino acids without introns. The deduced amino acid sequence showed a 60% identity to that of Aspegillus fumigatus galactomannoprotein MP1. The mnpA gene was expressed more abundantly in the wild-type than in the veA-null mutant. It was expressed at a lower level in fadA-null mutants, veA(+) or veA1 (regardless of their genetic background), than in the fadA(+) strain. However, the expression level was slightly higher in the veA(+) DeltafadA strain than in the veA1 DeltafadA strain. Furthermore, the amount of the mnpA transcript was higher in the flbA(+) strain than in the flbA-null mutant. These results indicate that the fadA and flbA genes in addition to the veA gene are necessary for the mnpA expression. The mnpA gene was expressed highly in vegetative mycelia and at a reduced level in sexual structures, but not in conidia. Its expression was almost constitutive during asexual development up to 18h after the transfer of mycelial balls onto a solid medium, and decreased thereafter. During sexual development, its expression reached its maximum 0-20h after the induction of sexual development, and then decreased thereafter. The mnpA-null mutant, that was still viable, showed no phenotypic difference in development, growth rate, protein secretion, and germination of both the ascospores and conidia from the wild-type. This suggests that the mannoprotein that is encoded by the mnpA gene is dispensable.
- Published
- 2003
38. Decolourization of azo dyes and a dye industry effluent by a white rot fungus Thelephora sp
- Author
-
K. Swaminathan, Keon-Sang Chae, and K. Selvam
- Subjects
Environmental Engineering ,Industrial Waste ,Bioengineering ,Thelephora ,Waste Disposal, Fluid ,Water Purification ,chemistry.chemical_compound ,Manganese peroxidase ,Organic chemistry ,Orange G ,Coloring Agents ,Waste Management and Disposal ,Laccase ,biology ,Renewable Energy, Sustainability and the Environment ,Basidiomycota ,General Medicine ,Lignin peroxidase ,biology.organism_classification ,Congo red ,Amido black 10B ,Biodegradation, Environmental ,chemistry ,Chemical Industry ,Azo Compounds ,Waste disposal ,Nuclear chemistry - Abstract
A white rot fungus Thelephora sp. was used for decolourization of azo dyes such as orange G (50 microM), congo red (50 microM), and amido black 10B (25 microM). Decolourization using the fungus was 33.3%, 97.1% and 98.8% for orange G, congo red and amido black 10B, respectively. An enzymatic dye decolourization study showed that a maximum of 19% orange G was removed by laccase at 15 U/ml whereas lignin peroxidase (LiP) and manganese dependent peroxidase (MnP) at the same concentration decolourized 13.5% and 10.8%, orange G, respectively. A maximum decolourization of 12.0% and 15.0% for congo red and amido black 10B, respectively, was recorded by laccase. A dye industry effluent was treated by the fungus in batch and continuous modes. A maximum decolourization of 61% was achieved on the third day in the batch mode and a maximum decolourization of 50% was obtained by the seventh day in the continuous mode. These results suggest that the batch mode of treatment using Thelephora sp. may be more effective than the continuous mode for colour removal from dye industry effluents.
- Published
- 2003
39. Isolation and Characterization of the mheA (Most Highly Expressed) Gene of Aspergillus oryzae
- Author
-
Ji Young Lim, Pengcheng Liu, Hee Seo Kim, Jong Hwa Kim, and Keon Sang Chae
- Subjects
biology ,Aspergillus oryzae ,Bioinformatics ,biology.organism_classification ,Isolation (microbiology) ,Microbiology ,Molecular biology ,Northern hybridization ,Research Note ,Infectious Diseases ,Gene expression ,mheA promoter ,Gene ,Peptide sequence - Abstract
The amino acid sequence of the mheA gene of Aspergillus oryzae encodes a putative metallothionein-like protein 1. The size of the mheA transcript was 497 nt and the mheA promoter was induced by glucose, consistent with results of analysis by Northern hybridization and with the pdcA promoter, respectively.
- Published
- 2012
40. The veA gene activates sexual development in Aspergillus nidulans
- Author
-
Kyung-Jin Kim, Hee-Seo Kim, Dong-Min Han, Kyu-Yong Han, Kwang-Yeop Jahng, and Keon-Sang Chae
- Subjects
Mutant ,Genes, Fungal ,Molecular Sequence Data ,Biology ,medicine.disease_cause ,Microbiology ,Aspergillus nidulans ,Fungal Proteins ,Open Reading Frames ,Start codon ,Gene Expression Regulation, Fungal ,Genetics ,medicine ,Amino Acid Sequence ,Gene ,Regulation of gene expression ,Mutation ,Base Sequence ,Neurospora crassa ,Nucleic acid sequence ,Wild type ,Molecular biology ,Open reading frame ,Phenotype - Abstract
The previously isolated gene complementing the veA1 mutation was confirmed to be the veA gene. The determined nucleotide sequence of the gene demonstrated that there is an open reading frame (ORF) of a 573 amino acid polypeptide. The nucleotide sequence matched some clones of which functions were not assigned yet and the amino acid sequence matched that of Neurospora crassa VeA-related protein with 61% similarity. The nucleotide sequence of the veA1 mutant gene differed from that of the wild type gene by only one nucleotide and the nucleotide G in the initiation codon ATG of the VeA ORF was mutated to the nucleotide T. Then, the mutant ORF may use the 37th methionine codon of the wild type one as a new initiation codon. The veA transcript was present in the conidia and in mycelia cultured for up to 14h and expressed almost constitutively at an increased level throughout the asexual and sexual developmental processes, suggesting that it may act from a relatively early developmental stage. Null mutants of the gene never formed sexual structures, even under conditions where sexual development preferentially occurs in wild types. Over-expressors of the gene formed larger numbers of sexual structures with a much reduced number of conidial heads than a control strain (a veA1 mutant), even under conditions where wild type strains form little sexual structure but form conidial heads very well, such as in the presence of a salt at high concentration. Furthermore, over-expressors could form Hulle cells and cleistothecia, even in a liquid culture. These results indicated that the veA gene is a positive regulator in sexual development and simultaneously a negative one in asexual development.
- Published
- 2002
41. Differential expression of house-keeping genes of Aspergillus nidulans during sexual development
- Author
-
Jungmi Kim, Dong Min Han, Kwang-Yeop Jahng, Keon-Sang Chae, Hyo-Young Jeong, Kyu-Yong Han, and Ga-Bee Cho
- Subjects
TBX1 ,Ribosomal Proteins ,Molecular Sequence Data ,Pair-rule gene ,Gene Dosage ,Aspergillus nidulans ,Fungal Proteins ,Gene Expression Regulation, Fungal ,Gene expression ,Gene cluster ,Genetics ,Amino Acid Sequence ,ORFS ,Cloning, Molecular ,Gene ,Expressed Sequence Tags ,biology ,Base Sequence ,Sequence Homology, Amino Acid ,Gene Expression Regulation, Developmental ,General Medicine ,biology.organism_classification ,Molecular biology ,Actins ,Housekeeping gene - Abstract
The rpl3 gene and the rpl37 gene for Aspergillus nidulans ribosomal protein L3 (RPL3) and RPL37, which were identified as located on chromosome I and chromosome III, respectively, were isolated from chromosome-specific cosmid libraries. The nucleotide sequences of both of the rpl3 gene and the rpl37 gene identified the ORFs of 392 amino acids and 92 amino acids, respectively. Both of the two genes were present in a single copy. The expression of both genes together with two other house-keeping genes, the rps16 gene for RPS16 and the gene for γ -actin, was analyzed during sexual development. All four genes showed nearly identical expression patterns in that each gene expression reached its maximum after 2 h, decreased thereafter, and increased again after 30–40 h of induction of sexual development.
- Published
- 2001
42. The increment of purine specific sodium nucleoside cotransporter mRNA in experimental fibrotic liver induced by bile duct ligation and scission
- Author
-
Keon-Sang Chae, Ji-Xing Nan, Sung Hee Lee, and Dong Hwan Sohn
- Subjects
Purine ,Male ,Population ,Biology ,Liver Cirrhosis, Experimental ,digestive system ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Cholestasis ,Drug Discovery ,medicine ,Animals ,Northern blot ,RNA, Messenger ,education ,Ligation ,Messenger RNA ,education.field_of_study ,Ion Transport ,cDNA library ,Organic Chemistry ,DNA ,medicine.disease ,Molecular biology ,Rats ,chemistry ,Carbon tetrachloride ,Molecular Medicine ,Bile Ducts ,Densitometry - Abstract
We investigated the expression profiles of rat fibrotic liver induced by bile duct ligation and scission (BDL/S) using the 3-directed cDNA libraries. The possibility that the 3′-directed cDNA library represents the mRNA population faithfully was examined by northern blots. During the northern analysis based on fibrotic liver expression profile, we found for the first time that purine specific sodium nucleoside cotransporter (SPNT) was upregulated in BDL/S-induced fibrotic liver. To determine whether the accumulation of bile juice could affect the expression of SPNT mRNA or not, we examined the change of SPNT mRNA expression at 3, 14, 28 days after BDL/S operation. No change in SPNT expression was observed in rat liver at 3 days after surgery. In contrast, there were significant increases in SPNT expression at 14 and 28 days after surgery. We also examined whether chronic liver damage affected SPNT mRNA expression. SPNT mRNA level was significantly increased in BDL/S-induced fibrotic rat liver, whereas no significant change was obserbed in fibrotic livers chronically exposed to carbon tetrachloride or dimethylnitrosamine. From the above results, although further study might be needed, it was considered that the increment of SPNT mRNA in BDL/S liver morphological compatibility to human was remarkable.
- Published
- 2001
43. BodyMap: a collection of 3' ESTs for analysis of human gene expression information
- Author
-
Kouichi Ito, Wakako Adachi, Hiroko Nakanishi, Toshiyuki Okumura, Katsuya Mizuno, Satoshi Kawasaki, Atsushi Fukushima, Hitoshi Nikaido, Kousaku Okubo, Kenichi Matsubara, Hiroko Ohashi, Junko Arimoto, Akiyo Shimizu-Matsumoto, Ryo Matoba, Yuko Nakao, Kota Shimizu, Jun Sese, Masahiro Yokoyama, Naohiro Hori, Hisae Yoshii, Jun Hashimoto, Akihiko Nakaya, Shinichi Morishita, Kazuhisa Maeda, Katsuji Murakawa, Shoko Kawamoto, Hiroshi Kuriyama, Teruyoshi Hishiki, Yuhiko Matsumoto, Keon-Sang Chae, Norikazu Monma, Tadashi Ohnishi, Reiko Ito, Koji Nishida, Ikko Ohno, Yasuhide Miyamoto, and Junji Yoshii
- Subjects
Genetics ,Expressed Sequence Tags ,Resource ,Expressed sequence tag ,DNA, Complementary ,Databases, Factual ,cDNA library ,Three prime untranslated region ,In silico ,Gene Expression Profiling ,UniGene ,Computational Biology ,Biology ,Sensitivity and Specificity ,Gene expression profiling ,Genes ,Organ Specificity ,GenBank ,Humans ,Cloning, Molecular ,Gene ,3' Untranslated Regions ,Genetics (clinical) - Abstract
BodyMap is a collection of site-directed 3′ expressed sequence tags (ESTs) (gene signatures, GSs) that contains the transcript compositions of various human tissues and was the first systematic effort to acquire gene expression data. For the construction of BodyMap, cDNA libraries were made, preserving abundance information and histologic resolutions of tissue mRNAs. By sequencing 164,000 randomly selected clones, 88,587 GSs that represent chromosomally coded transcripts have been collected from 51 human organs and tissues. They were clustered into 18,722 independent 3′ termini from transcripts, and more than 3000 of these were not found among ESTs assembled in UniGene (Build 75). Assessment of the prevalence of polyadenylation signals and comparison with GenBank cDNAs indicated that there was no significant contamination by internally primed cDNAs or genomic fragments but that there was a relatively high incidence (12%) of alternative polyadenylation sites. We evaluated the sensitivity and resolution of expression information in BodyMap by in silico Northern hybridization and selection of tissue-specific gene probes. BodyMap is a unique resource for estimation of the absolute abundance of transcripts and selection of gene probes for efficient hybridization-based gene expression profiling. [BodyMap data are available at http://bodymap.ims.u-tokyo.ac.jp.]
- Published
- 2000
44. A human cDNA sequence homologue of bovine phosphatidylethanolamine-binding protein
- Author
-
Naohiro Hori, Atsushi Fukushima, Keon-Sang Chae, Kousaku Okubo, Katsuji Murakawa, Ryo Matoba, and Kenichi Matsubara
- Subjects
Phosphatidylethanolamine ,Base Sequence ,Phosphatidylethanolamines ,Binding protein ,Molecular Sequence Data ,Nucleic acid sequence ,DNA ,General Medicine ,Biology ,Molecular biology ,Phosphatidylethanolamine Binding Protein ,chemistry.chemical_compound ,chemistry ,Cell culture ,Complementary DNA ,Genetics ,Animals ,Humans ,Cattle ,Amino Acid Sequence ,Carrier Proteins ,Gene ,Sequence (medicine) - Abstract
Sequencing of about 1000 3′-directed cDNA clones from the human HepG2 cell line revealed that about half of them represent transcripts of abundantly or moderately expressed genes, about 70% of which are novel. We identified one of these clones as encoding the human homologue of bovine phosphatidylethanolamine-binding protein.
- Published
- 1994
45. The nsdC Gene Encoding a Putative C2H2-Type Transcription Factor Is a Key Activator of Sexual Development in Asbergillus nidulans.
- Author
-
Hye-Ryun Kim, Keon-Sang Chae, Kap-Hoon Hant, and Dong-Min Han
- Subjects
- *
ASPERGILLUS , *PLANT phenology , *PLANT development , *MESSENGER RNA , *PLANT growth - Abstract
The formation of the Aspergillus nidulans fruiting body is affected by a number of genetic and environmental factors. Here, the nsdC (never in sexual development) gene-encoding a putative transcription factor carrying a novel type of zinc-linger DNA-binding domain consisting of two C2H2's and a C2HC motif that are highly conserved in most fungi hut not in plants or animals-was investigated. Two distinct transcripts of 2.6 and 3.0 kb were generated from nsdC. The 2.6-kb mRNA accumulated differentially in various stages of growth and development, while the level of the 3.0-kb mRNA remained relatively constant throughout the life cycle. While the deletion of nsdC resulted in the complete loss of fruiting body formation under all conditions favoring sexual development, overexpression of nsdC not only enhanced formation of fruiting bodies (cleistothecia) hut also overcame inhibitory effects of certain stresses on cleistothecial development, implying that NsdC is a key positive regulator of sexual development. Deletion of nsdC also retarded vegetative growth and hyperactive asexual sporulation, suggesting that NsdC is necessary not only for sexual development hut also for regulating asexual sporulation negatively. Overexpression of VeA or nsdD does not rescue the failure of fruiting body formation caused by nsdC deletion. Furthermore, nsdC expression is not affected by either VeA or NsdD, and vice versa, indicating that NscD regulates sexual development independently of VeA or NsdD. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
46. The veA gene is necessary for the negative regulation of the veA expression in Aspergillus nidulans.
- Author
-
Hyoun-Young Kim, Kap-Hoon Han, Mimi Lee, Miae Oh, Hee-Seo Kim, Xie Zhixiong, Dong-Min Han, Kwang-Yeop Jahng, Jong Hwa Kim, and Keon-Sang Chae
- Subjects
ASPERGILLUS ,MONILIACEAE ,HEREDITY ,MOBILE genetic elements ,MOLECULAR genetics - Abstract
The veA gene is one of the key genes in regulating sexual development of Aspergillus nidulans. During the study on the veA gene, it was observed that the veA expression level is slightly higher in a veA1 mutant than in a wild type at 37°C, suggesting that the wild type veA gene is necessary for the negative regulation of the veA expression. In the veA1 mutant, the veA expression was higher than in a wild type grown at 42°C but equal at 30°C. Furthermore, in a veA deletion mutant having its own promoter and the N-terminus of the VeA ORF, expression of the N-terminus by the veA promoter was highly up-regulated, supporting the possibility that the veA gene is important for the negative regulation of the veA expression. Analyses of the lacZ transcript and the β-galactosidase activity from the reporter strains in the veA1 background, which were constructed by transformation of the lacZ reporter plasmids containing the lacZ gene under the control of the intact or the truncated veA promoters from the −943 to +262 bp region, showed that the truncated promoters produced more veA transcript and higher β-galactosidase activity than the intact one at 30°C, but equal at 42°C. In addition, the serial-deletion analysis of the veA promoter identified a crucial region in the promoter from −943 to −740 bp for this derepression of the veA expression. Taken together, these results indicated that the veA gene is necessary for the negative regulation of the veA expression. Moreover, the veA expression was derepressed in the light-illuminated condition, where the VeA protein is hardly transported into the nucleus. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
47. The GanB Gα-Protein Negatively Regulates Asexual Sporulation and Plays a Positive Role in Conidial Germination in Aspergillus nidulans.
- Author
-
Mi-hee Chang, Keon-sang Chae, Dong-Min Han, and Kwang-Yeop Jahng
- Subjects
- *
G proteins , *MEMBRANE proteins , *GENETICS , *ASEXUAL reproduction , *ASPERGILLUS nidulans , *FUNGI imperfecti , *BACTERIAL spores - Abstract
We isolated the ganB gene encoding the Gα-protein homolog from Aspergillus nidulans. To investigate the cellular function of GanB, various mutant strains were isolated. Deletion of constitutively inactive ganB mutants showed conidiation and derepressed brlA expression in a submerged culture. Constitutive activation of GanB caused a reduction in hyphal growth and a severe defect in asexual sporulation. We therefore propose that GanB may negatively regulate asexual sporulation through the BrlA pathway. In addition, deletion or constitutive inactivation of GanB reduced germination rate while constitutive activation led to precocious germination. Furthermore, conidia of a constitutively active mutant could germinate even without carbon source. Taken together, these results indicated that GanB plays a positive role during germination, possibly through carbon source sensing, and negatively regulates asexual conidiation in A. nidulans. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
48. Presence of a mannoprotein, MnpAp, in the hyphal cell wall of Aspergillus nidulans.
- Author
-
Hyo-Young Jeong, Keon-Sang Chae, and Sung Soo Whang
- Subjects
- *
ASPERGILLUS nidulans , *CELL membranes , *IMMUNOELECTROPHORESIS , *PROTEINS , *IMMUNOGOLD labeling - Abstract
The presence of a mannoprotein, MnpAp, in the hyphal cell wall of Aspergillus nidulans was examined by immunogold electron microscopy using a mnpA-null mutant as a negative control. The hyphal cell wall of wild type consisted of two layers--an electron-dense smooth outer layer and an electron-translucent inner layer--while the hyphal cell wall of the mnpA-null mutant had an electron-dense irregular outer layer together with the electron-translucent inner layer. In wild type, MnpAp was present throughout the electron-translucent layer of the hyphal cell wall but was absent from the conidial cell wall. In the mnpA-null mutant, MnpAp was absent from the cell walls of both cell types. These results indicate that MnpAp is present in the hyphal cell wall and that it influences cell wall surface structure. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
49. The lsdA gene is necessary for sexual development inhibition by a salt in Aspergillus nidulans.
- Author
-
Dong Whan Lee, Serha Kim, Soon-Ja Kim, Dong Min Han, Kwang-Yeop Jahng, and Keon-Sang Chae
- Subjects
GENES ,ASPERGILLUS ,NUCLEIC acids ,NUCLEOTIDE sequence ,AMINO acids ,HEREDITY ,GENE expression - Abstract
Using one of 17 expressed sequence tags (ESTs) previously identified as specific to the late sexual developmental (LSD) stage of Aspergillus nidulans, a gene for the subject EST was isolated. The determined DNA sequences revealed an open reading frame encoding a 356 amino acid polypeptide which does not share a sequence similarity to previously identified genes or proteins. The isolated gene was named lsdA (late sexual development), since it was expressed abundantly at the LSD stage. The lsdA gene expression began earlier than at the LSD stage. Disruption of the lsdA gene in the veA
+ background strongly induced sexual development under conditions where sexual development in wild-type strains is almost completely inhibited. In contrast, in the veA1 background, an lsdA null mutant failed to show any phenotypic difference in sexual development under the various conditions tested. These results indicate that the lsdA gene may be responsible for inhibiting the sexual development of veA+ strains by a high concentration of a salt. [ABSTRACT FROM AUTHOR]- Published
- 2001
- Full Text
- View/download PDF
50. Microbial decolorization of azo dyes and dye industry effluent by Fomes lividus.
- Author
-
K. Selvam, K. Swaminathan, and Keon-Sang Chae
- Abstract
The white rot fungus, Fomes lividus, was isolated from the logs of Shorea robusta in the Western Ghats region of Tamil Nadu, India. The fungus was tested for decolorization of azo dyes such as orange G (50 μM) congo red (50 μM) amido black 10B (25 μM) and also for colour removal from dye industry effluents. The results revealed that the fungus could remove only 30.8% of orange G in the synthetic solution, whereas congo red and amido black 10B were removed by 74.0 and 98.9% respectively. A dye industry effluent was treated by the fungus in batch and continuous mode. In batch mode treatment, a maximum decolorization of 84.4% was achieved on day 4, and in continuous mode a maximum decolorization of 37.5% was obtained on day 5. The colour removal by the basidiomycete fungus might be due to adsorption of the dyes to the mycelial surface and metabolic breakdown. These results suggested that the batch mode treatment of Fomes lividus is one of the most efficient ways for colour removal in dye industry effluents. [ABSTRACT FROM AUTHOR]
- Published
- 2003
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