• Korean Journal of Microbiology
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• v.26 no.2
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• pp.93-100
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• 1988

In order to understand the regulation of glutamate dehydrogenase(GDH) synthesis in Brevibacterium flavum, we have isolated a mutant lacking NADP-linked GDH activity by ethlmethane sulfonate treatment. The $gdh^-$ mutant was grown on the minimal plate with 1mM ammonium chloride and not that with 300mM ammonium chloride. The cell-free extracts from $gdh^-$ mutant and prototroph were also examined with glutamine synthetase(GS) and glutamate synthase (GOGAT) production by niteogen sources. The growth of $gdh^-$ mutant in presence of 20mM ammonium chloride means that GOGAT synthesis is sufficient to allow growth in this condition. GS production of $gdh^-$ mutant as well as parental strain was induced by 1mM urea and ammonium tartrate, but it was repressed by higher concentration of ammonia, and also induced by 20mM to 50mM glutamate as a substrate. It was special attention that GOGAT synthesis from $gdh^-$ strain was more repressed by higher concentration of ammonia than prototroph as described in E. coli system.

• Microbiology and Biotechnology Letters
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• v.29 no.2
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• pp.96-103
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• 2001

Phaffia rhodozyma is the most promising microbial source of astaxanthin production, though wild-type strains are needed to increase the astaxanthin content for commercial production. To increase astaxanthin content for commercial production, a mutant strain of P. rhodozyma was selected and culture conditions of the mutant selected were optimized. P. rhodozyma was treated with mutagenic agent such as NTG, acriflavine, and UV in serial order and carotenoids hyper-producing mutant strain was selected based on the capabilities of cell growth on the agar plate containing chemical inhibitors and carotenoids production. Among the mutants tested, a mutant WS-2 was finally selected. Mutant WS-2 produced 1.26mg carotenoids/g-dry cell weight and this value was about- 4-folds higher than that of wild-type. The optimum culture conditions were $24^{\circ}C$ of temperature, 1.5vvm of aeration and 300rpm of agitation. In the optimized condition, cell and carotenoids concentrations were 7.62g/l and 14.9mg/l, respectively.

• Journal of Sericultural and Entomological Science
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• v.42 no.2
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• pp.86-92
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• 2000

Studies were carried out to investigate the phenotypic characteristics of the non-molting mutant (nm-f) which was mapped on the 2nd linkage group. The results obtained were as follows : The nm-f mutant was distinguishable in the 3rd day of hatching. About 80 percentage of the non-molting mutant larvae died at the first instar within 10 days of hatching. The remaining larvae survived to the 2nd ad the 3rd instar but did not live to the final instar. There was no difference in non-molting nutant manifestation between hibernating and artificial hatching eggs. As a result of hemolymph protein analysis, the protein content on nm-f mutant was less than the normal larvae's. Therefore, we conclude that the characterization of nm-f is similar to the already known strains of non-molting mutant and the shortage of hemolymph protein is closely related to the non-molting characteristic in nm-f.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.233.2-233.2
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• 2003

This experiment study was carried out to prove the efficacy of Cheongpajeon(CPJ) extract in ovariectomized rats. 40 rats were divided into 4 groups, administrated saline after sham operation group(sham-op), administered saline after ovariectomy group(control), administered CPJ 1g/kg after ovariectomy group and administered Livial 0.042mg/kg after ovariectomy group(positive control). We examined the water extract of CPJ that is capable of affecting osteoblast proliferation using MG-63 and HOS-TE85. (omitted)

• Journal of Microbiology
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• v.33 no.2
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• pp.146-148
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• 1995

Coprinus congregatus has a membrane-associated laccase which is not secreted into culture media. A mutant monokaryon obtained, by U. V. irradiation followed by protoplast generation and regeneration method, was successfully isolated. When the mutant was grown on a agar plate or in a liquid medium, it secreted laccase while the wild type did not under the same growth conditions. The laccase of the mutant was compared with that of wild type did not under the same growth conditions. The laccase of the mutant was compared with that of wild type of native PAGE analysis, and showed identical mobility.

• Microbiology and Biotechnology Letters
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• v.21 no.6
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• pp.520-526
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• 1993

A morphologically different form of Ganoderma lucidum was isolated from a cultivator's farm, and its optimum growth conditions were determined. A major difference in their morphology was color of fruit bodies. Fruit bodies of the mutant were white wherase those of normal Ganoderma lucidum were red. Spores of the mutant were global and mycelia were thin. Mycelial growth of this white mutant was favorable on potato sucrose agar medium, and optimum pH of the medium was 5.5.

• Journal of Microbiology and Biotechnology
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• v.17 no.8
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• pp.1399-1402
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• 2007

The virulence of superoxide dismutase (SOD) mutants of Vibrio vulnificus, as tested by intraperitoneal injection into mice, decreases in the order of sodC mutant, sodA mutant, and sodB mutant lacking CuZnSOD, MnSOD, and FeSOD, respectively. The survival of SOD mutants under superoxide stress also decreases in the same order. The virulence of soxR mutant, which is unable to induce MnSOD in response to superoxide, is similar to that of the sodA mutant, as the survival of the soxR mutant under superoxide stress is similar to that of the sodA mutant. Consistently, the lowered survival of the soxR mutant is complemented not only with soxR but also with sodA. Thus, the virulence of V. vulnificus is significantly affected by the cellular level of SOD activity, and an increase in SOD level through MnSOD induction by SoxR under superoxide stress is essential for virulence.

• Journal of Plant Biotechnology
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• v.3 no.3
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• pp.151-157
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• 2001

In order to breed barley lines with reduced viscosity of wort, a fractured starch mutant of naked barley cultivar, Nubet, was obtained from the M2 seeds mutated by the diethyl sulfate treatment. Seeds of this fractured starch mutant were opaque and the endosperm consists of angular, irregular and fractured starch. The mutant was caused by single recessive mutation and assigned by the symbol fra. The gene was located on chromosome 4, distal in long arm by linkage recombinations using translocation homozygote lethal test set. The linkage value between the fractured starch mutant and 72-4a, 72-4d were 26.0$\pm$4.9, 34.2$\pm$3.1 percent respectively. In addition to the reduced seed size, fewer kernels per spike and higher tillering ability, lower $\beta$-glucan viscosity and higher lysine content of the grain were associated with this mutant. $\beta$-glucan viscosity of the Nubet grains increased from 3 weeks after anthesis to matury and most of the viscose substances appeared to be stored in the middle of the endosperm tissue. Since the mutant grains showed better milling property as compared to Nubet, it can be used as breeding resources to develope new barley cultivars for maltins and milling purpose.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.1
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• pp.163-169
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• 1996

인위돌연변이 유기에 의해 벼로부터 새로운 유전형질체를 개발하기 위하여 낙동벼(모품종)에서 고정된 엽록소 결핍계통(ch mutant)을 선발하였다. 이 계통은 생육 초기부터 엽록소결핍으로 정상엽에 비하여 노란색을 나타내기 때문에 엽록소의 광합성 관여 유전자탐색에 이용가능하다. ch mutant는 전 생육기간 동안 모품종의 51~87% 정도의 엽록소 함량을 보였으나 엽록소 a/b 함량비는 차이가 없었다. ch mutant의 총 엽록소 함량은 모품종의 70.2%였으면 anthocyanin 함량과 flavonol 함량은 각각 285%와 142% 로 높은 함량비를 나타냈다. ch mutant의 카로티노이드 함량은 모품종의 71.1%였고, 크산토필 함량은 56.6%였다. 특히 카로티노이드 성분중 lutein과 neoaxanthin 함량은 각각 모품종의 32%와 34.4%로 매우 낮았으며, $\beta$-카로틴은 차이가 없으나 antheraxsnthin 함량은 106.9%오히려 증가하였다. 개엽상태에서나 군락 상태에서 ch mutant의 반사율과 투과율은 모두 모품종에 비하여 높아 광흡수량은 저하되었다. ch mutant는 모품종에 비하여 출수기가 5일 늦고 간자, 수장, 주당수수, 수당 입수, 임실율, 천립 중 수량에 감소하였다. ch mu-tant와 모푸종은 esterase, phosphogluose isomerase, malic enzyme, hexokinase 동위 효소의 밴드 패턴에서 유의할 만한 차이를 나타내지 않았으나 엽록체 단백질의 경우 주요 밴드인 60KD의 분자량에서 차이를 보였다.

• Mycobiology
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• v.30 no.3
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• pp.160-165
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• 2002

Aspergillus niger has been used as a host to express many heterologous proteins. It has been known that the presence of an- abundant protease is a limiting factor to express a heterologous protein. The protease deficient mutant of A. niger was obtained using UV-irradiation. A total of $1{\times}10^5$ spores were irradiated with $10{\sim}20%$ survival dose of UV, 600 $J/m^2$ at 280 nm, and the resulting spores were screened on the casein-gelatin plates. Ten putative protease deficient mutants showing the reduced halo area around colonies were further analyzed to differentiate the protease deficient mutant from other mutant types. Among ten putative mutants, seven mutants showed significant growth defect on nutrient rich medium and two mutants appeared to be the secretory mutants, which resulted in the impaired secretion of extracellular proteins including proteases. A mutant $pro^--20$ showed reduced halo zone without any notable changes in growth rate. In addition, the starchdegrading and glucose oxidase activities in the culture filtrate of $pro^--20$ mutant showed the similar range as that of the parental strain, which suggested that the $pro^--20$ mutant ought to be the protease deficient mutant rather than a secretory mutant. The reduced proteolytic activity of the $pro^--20$ was demonstrated using SDS-fibrin zymography gel. The reduced extracellular proteolysis was quantified by casein degradation assay and, comparing with the parental strain, less than 30% residual extracellular protease activity was detected in the culture filtrate of the $pro^--20$ mutant. The bio-activity of an exogenously supplemented hGM-CSF(human Granulocyte-Macrophage Colony Stimulating Factor) in the culture filtrate of $pro^--20$ mutant was detected until eight times more diluted preparations than that of the parental strain.