• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.135-139
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• 2002

Yeast cells respond to condition of amino acid starvation by synthesizing GCN4, a typical eukaryotic transcriptional activator, which regulates the expression of many amino acids biosynthetic genes. By introducing point mutations in the DNA binding domain of GCN4, mutants with normal DNA binding activity but defective in transcriptional activity were isolated to identify unknown proteins that could suppress the mutant phenotype under an amino acid depletion condition. As a result, SSB(Stress-Seventy B) subfamily proteins were identified as suppressors of mutant GCN4. SSB proteins were known as a member of yeast hsp70 family that probably aids passage of nascent chain through ribosomes. Among them, the mechanism of suppression by SSB2 on the defective GCN4 mutant strains is under investigation. Gcn4p directly interacts with Ssb2p through the basic DNA binding domain of GCN4. It suggests the possibility that physical interaction might induce the transcriptional activation of Gcn4p.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.637-641
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• 2010

The antibiotics-resistance profiles of 28 strains of Vibrio parahaemolyticus isolated from seawater were investigated. All of the strains studied were resistant to ampicillin (100%), but susceptible to 12 other antibiotics. The minimum inhibitory concentration (MIC) of V. parahaemolyticus to ampicillin was as high as $1,024-2,048\;{\mu}g{\cdot}mL^{-1}$. The phenotype of strain 8 changed from ampicillin-resistant to susceptible with an in-frame deletion mutant of VPA0477, a putative ${\beta}$-lactamase gene, and the MIC for ampicillin of the mutant strain was $1{\mu}g{\cdot}mL^{-1}$. In conclusion, our findings suggest that the VPA0477 gene acts as a ${\beta}$-lactamase in ampicillin-resistant V. parahaemolyticus strains.

• Journal of the Korean Society of Tobacco Science
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• v.17 no.2
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• pp.114-119
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• 1995

Cultivars of Nicotiana tabacum L. normally have pink flowers, but the flue-cured tobacco mutant line, BU 8832-85, had white flower. The mutant line was crossed with five normal varieties of KF 109, NC 82, TC 499, NC 567 and Coker 176. All Fl plants showed pink flower. The progenies of F2 generations were segregated with the phenotypic ratio 9 : 3 : 4 with pink, varigated(a recombinant type) and white flower, respectively. Test-cross populations showed 1 : 1 : 2 ratios. These results showed that the white flower character was controlled by two recessive genes. The genes were designated as FFCC for pink and ffcc for white flower. The recessive gene ff was epistatic to C and c. Therefore, white flower had a recessive epistasis gene.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.4
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• pp.348-355
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• 2006

Phenotypes of panicle, hull and seed of mutant rice (Oryza sativa L.) were characterized. Panicle mutants were classified in 4 groups with their internode length of main rachis, primary rachis, secondary rachis and pedicel. Hull and seed mutants were grouped into 12 based on their mutant characters in shape, size and color of seeds. These natural and spontaneous mutant collections showed distinct phenotypes to wild type rice. This might be useful for the identification of the functions of genetic factors in the Mendelian inheritance.

• Journal of Microbiology and Biotechnology
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• v.2 no.2
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• pp.102-107
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• 1992

For the purpose of producing L-ornithine by microbial fermentation, mutant strains were developed from glutamate-producing bacteria by mutagenesis using N-methyl-N'-nitro-N-nitrosoguanidine (NTG) and UV irradiation. Brevibacterium ketoglutamicum BK1046, a L-citrulline auxotroph which is also resistant to arginine hydroxamate (Arghx), was isolated and selected as the best producer of L-ornithine. This strain was capable of producing L-ornithine at a concentration of 24 g/l after 69 hours of cultivation in the 21 jar fermentor. The optimum supplementary level of L-arginine, a substitute for L-citrulline, was found to be about 0.2 g/l in the shake-flask fermentation.

• Mycobiology
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• v.28 no.3
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• pp.119-122
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• 2000

Phytases (myo-inositol hexakisphosphate phosphohydrolase; EC 3.1.3.8) are enzymes which catalyze the hydrolisys of phytate into myo-inositol and inorganic phosphates. Phytases are found in plants and a variety of microorganisms. Aspergillus species were treated with 254 nm of UV irradiation for the screening of phytase overproducing mutant strains. At 15 minute irradiation, the survivals of population were less than 5%, and UV irradiation time was decided at 20 minute for the isolation of mutant strains. Four UV mutant strains in A. oryzae (YUV-47, -169, -341, -511) and six in A. ficuum (FUV-17, -36, -69, -193, -317, -419) were isolated on PSM media containing ammonium phosphate. The specific enzyme activities of A. ficuum mutants are 110 to 140% higher than that of wild type.

• Journal of Microbiology
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• v.44 no.3
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• pp.320-326
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• 2006

Pasteurella multocida is an important veterinary and opportunistic human pathogen. In particular, strains of P. multocida serogroup D cause progressive atrophic rhinitis, and produce a potent, intracellular, mitogenic toxin known as P. multocida toxin (PMT), which is encoded by the toxA gene. To further investigate the toxigenic and pathogenic effects of PMT, a toxA-deleted mutant was developed by homologous gene recombination. When administrated to mice, the toxigenicity of the toxA mutant P. multocida was drastically reduced, suggesting that the PMT constributes the major part of the toxigenicity of P, multocida. Similar results were obtained in a subsequent experiment, while high mortalities were observed when toxA(+) P. multocida bacterial culture or culture Iysate were administrated. Mice immunized with toxA(-) P. multocida were not protected (none survived) following challenge with toxA(+) P. multocida or bacterial culture Iysate (toxin). These results suggest that the toxigenicity of P. multocida is mainly derived from PMT.

• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.313-314
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• 1991

- The cyclodextrin glucanotransferase (CGTase) of a mutant of Bacillus stearothermophilus was purified in one step by affinity chromatography. The recovery was 95%. The specific activity of the CGTase increased from 26.2 U/mg protein to 485.5 U/mg protein. The purified CGTase was almost homogeneous by SDS-polyacrylamide gel electrophoresis. The one-step purification proved to be feasible with the mutant in contrast to the parent strain, which required pre-purification step of ammonium sulfate precipitation.

• YAKHAK HOEJI
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• v.36 no.5
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• pp.469-473
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• 1992

Yeast alcohol dehydrogenase (YADH) has an acidic residue that interacts with the 2'- and 3'-hydroxyl groups of the adenosine ribose of the $NAD^+$ coenzyme. The acidic residue of Asp-223 (according to horse liver alcohol dehydrogenase amino acid sequence) is supposed to determine the coenzyme specificity for $NAD^+$ rather than $NADP^+$. We mutated Asp-223 to leucine and the mutant YADH was expressed in yeast and characterized for the coenzyme specificity. The turnover numbers of mutant enzyme for $NAD^+$ and ethanol were decreased 3.5- and 4.8-fold compared to wild-type enzyme, respectively. Contrastively, catalytic specificity for $NADP^+$ was increased 13-fold. As a result, the mutant YADH also employed $NADP^+$ as a coenzyme.

• Proceedings of the IEEK Conference
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• summer
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• pp.417-420
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• 2004

Caenorhabditis (C) elegans is often used in genetic analysis in neuroscience because its simple organism; an adult hermaphrodite contains only 302 neuron. So the worm is often used to study of cancer, alzheimer disease, aging, etc. To analysis mutant type of the worm, an experienced observer was able to subjectively before, but requirements for objective analysis are now increasing. For this reason, we use automated tracking systems to extract global movement coordinate of the worm. In this paper, we extract features, which are related on reversal and movement of the worm. Using these features, we quantitatively analysis 6 type mutant by movement and reversal characteristic.