• Journal of Microbiology and Biotechnology
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• 제29권12호
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• pp.1982-1992
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• 2019

The alkaliphilic, calcium carbonate precipitating Bacillus sp. strain AK13 can be utilized in concrete for self-repairing. A statistical experimental design was used to develop an economical medium for its mass cultivation and sporulation. Two types of screening experiment were first conducted to identify substrates that promote the growth of the AK13 strain: the first followed a one-factor-at-a-time factorial design and the second a two-level full factorial design. Based on these screening experiments, barley malt powder and mixed grain powder were identified as the substrates that most effectively promoted the growth of the AK13 strain from a range of 21 agricultural products and by-products. A quadratic statistical model was then constructed using a central composite design and the concentration of the two substrates was optimized. The estimated growth and sporulation of Bacillus sp. strain AK13 in the proposed medium were 3.08 ± 0.38 × 10⁸ and 1.25 ± 0.12 × 10⁸ CFU/ml, respectively, which meant that the proposed low-cost medium was approximately 45 times more effective than the commercial medium in terms of the number of cultivatable bacteria per unit price. The spores were then powdered via a spray-drying process to produce a spore powder with a spore count of 2.0 ± 0.7 × 10⁹ CFU/g. The AK13 spore powder was mixed with cement paste, yeast extract, calcium lactate, and water. The yeast extract and calcium lactate generated the highest CFU/ml for AK13 at a 0.4:0.4 ratio compared to 0.4:0.25 (the original ratio of the B4 medium) and 0.4:0.8. Twenty-eight days after the spores were mixed into the mortar, the number of vegetative cells and spores of the AK13 strain had reached 10⁶ CFU/g within the mortar. Cracks in the mortar under 0.29 mm were healed in 14 days. Calcium carbonate precipitation was observed on the crack surface. The mortar containing the spore powder was thus concluded to be effective in terms of healing micro-cracks.

• Archives of Pharmacal Research
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• 제16권1호
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• pp.62-67
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• 1993

A series of 12 pyrimidine derivatives were prepared and tested in vitro against growth, sporulation and nucleic acids of Fusarium oxysporum f. sp. lycopersici and Helminthosporium oryzae. Intorduction of thiazole ring together with two aryl groups to 2-aminopyrimidine induced drastic toxicity for both fungi. Pyrimidine derivatives with aryl groups were less toxic. Nitro groups were found to enhance the toxicity of the pyrimidine derivatives especially when substituted in ortho-position of the aryl groups. Inhibition of nudeic acids synthesis of both fungi was attributed mainly to the presence of thiazole ring.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2005년도 International Meeting of the Microbiological Society of Korea
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• pp.214.1-214
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• 2005

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1975년도 학술발표논문집
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• pp.109.1-109
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• 1975

The family Bacillaceae에 속하는 모든 미생물은 endospore를 형성하는 것이 그 특성이며 포자형성은 일련의 생화학적 반응은 물론 형태ㆍ구조적 변화를 수반하는 질서 정연한 원시적인 생물분화의 일종이다. 따라서 포자형성 발아에 관한 연구가 많이 이루어졌고 또 현재도 활발히 진행되고 있다. 산업미생물학도로서 흥미있는 점은 산업적으로 유용한 몇가지 생화학물질이 포자형성 과정과 특별히 관련되어 생산된다는 점이며 이중 몇 가지 효소와 항생물질 그리고 독소에 관하여 간략히 고찰해 보고자 한다.

• Mycobiology
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• 제51권3호
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• pp.164-168
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• 2023

This study examined the effects of myristate on an asymbiotic culture of Rhizoglomus intraradices, a species of arbuscular mycorrhizal fungi (AMF; Glomeromycota). Mycelial growth and sporulation in a modified medium containing myristate were observed. The findings demonstrated that myristate induced R. intraradices spore formation, with daughter spores having a smaller diameter than the parent spores. This observation is consistent with previous studies on other Rhizoglomus species. Further studies are needed to investigate the potential for continuous culture, mass production using daughter spores, and the application of AMF colonization techniques in plants.

• 한국균학회지
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• 제4권1호
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• pp.53-58
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• 1976

This study was undertaken to investigate the direct effect of three different kinds of steroid to Trichophyton(T.) mentagrophytes growth in vitro. A loopful of T. mentagrophytes was inoculated into Sabouraud's media and Sabouraud's media containing various concentrations of dexamethasone (0.04%-0.00004%) prednisolone (0.25%-0.00025%), triamcinolone acetonide (0.2%-0.0002%), Sabouraud's media containing imidazole nitrate (econasole nitrate) 10 micro gm. per cc. of media, and Sabouraud's media containing econazole nitrate $10{\mu}g$ per cc. of media of various dexamethasone concentrations (0.04%-0.00004%). After inoculation they were left for two weeks at room temparature and the colony diameter were compared between Sabouraud's media and Sabouraud's media containing various concentrations, of three different steroids, Sabouraud's media containing econazole nitrate and Sabouraud's media containing econazole nitrate of various dexamethasone concentrations. For complementary study, hanging slide culture were done between Sabouraud's media and Sabouraud's media containing various dexamethasone concentrations to compare the degree of branching of hyphae and sporulation serially. The study results were as follows: 1. There is no significant difference in growth rate of T. mentcgrophytes between Sabouraud's media and Sabouraud's media containing various concentrations of three different steroids. 2. There is no significant difference in growth rate of T. metagrophytes between Sabouraud's media containing econazole nitrate 10 micro gm per cc. of media and Sabouraud's media containing econazole nitrate 10 micro gm per cc. of media of various dexamethasone concentrations. 3. In hanging slide culture, there is no significant difference in branching of hyphae and sporulation between Sabouraud's media and Sabouraud's media containing various dexamethasone concentrations.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1867-1876
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• 2017

Most of the biosynthetic pathways for secondary metabolites are influenced by carbon metabolism and supply of cytosolic NADPH. We engineered carbon distribution to the pentose phosphate pathway (PPP) and redesigned the host to produce high levels of NADPH and primary intermediates from the PPP. The main enzymes producing NADPH in the PPP, glucose 6-phosphate dehydrogenase (encoded by zwf1 and zwf2) and 6-phosphogluconate dehydrogenase (encoded by zwf3), were overexpressed with opc encoding a positive allosteric effector essential for Zwf activity in various combinations in Streptomyces lividans TK24. Most S. lividans transformants showed better cell growth and higher concentration of cytosolic NADPH than those of the control, and S. lividans TK24/pWHM3-Z23O2 containing zwf2+zwf3+opc2 showed the highest NADPH concentration but poor sporulation in R2YE medium. S. lividans TK24/pWHM3-Z23O2 in minimal medium showed the maximum growth (6.2 mg/ml) at day 4. Thereafter, a gradual decrease of biomass and a sharp increase of cytosolic NADPH and sedoheptulose 7-phosphate between days 2 and 4 and between days 1 and 3, respectively, were observed. Moreover, S. lividans TK24/pWHM3-Z23O2 produced 0.9 times less actinorhodin but 1.8 times more undecylprodigiosin than the control. These results suggested that the increased NADPH concentration and various intermediates from the PPP specifically triggered undecylprodigiosin biosynthesis that required many precursors and NADPH-dependent reduction reaction. This study is the first report on bespoke metabolic engineering of PPP routes especially suitable for producing secondary metabolites that need diverse primary precursors and NADPH, which is useful information for metabolic engineering in Streptomyces.

• The Plant Pathology Journal
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• 제33권1호
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• pp.95-100
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• 2017

Fungicide-resistant Alternaria alternata impede the practical control of the Alternaria diseases in crop fields. This study aimed to investigate cytological fungicide resistance mechanisms of A. alternata against dicarboximide fungicide iprodione. A. alternata isolated from cactus brown spot was cultured on potato-dextrose agar (PDA) with or without iprodione, and the fungal cultures with different growth characteristics from no, initial and full growth were observed by light and electron microscopy. Mycelia began to grow from one day after incubation (DAI) and continued to be in full growth (control-growth, Con-G) on PDA without fungicide, while on PDA with iprodione, no fungal growth (iprodione-no growth, Ipr-N) occurred for the first 3 DAI, but once the initial growth (iprodione-initial growth, Ipr-I) began at 4-5 DAI, the colonies grew and expanded continuously to be in full growth (iprodione-growth, Ipr-G), suggesting Ipr-I may be a turning moment of the morphogenetic changes resisting fungicidal toxicity. Con-G formed multicellular conidia with cell walls and septa and intact dense cytoplasm. In Ipr-N, fungal sporulation was inhibited by forming mostly undeveloped unicellular conidia with degraded and necrotic cytoplasm. However, in Ipr-I, conspicuous cellular changes occurred during sporulation by forming multicellular conidia with double layered (thickened) cell walls and accumulation of proliferated lipid bodies in the conidial cytoplasm, which may inhibit the penetration of the fungicide into conidial cells, reducing fungicide-associated toxicity, and may be utilized as energy and nutritional sources, respectively, for the further fungal growth to form mature colonies as in Ipr-G that formed multicellular conidia with cell walls and intact cytoplasm with lipid bodies as in Con-G.

• Parasites, Hosts and Diseases
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• 제31권3호
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• pp.201-206
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• 1993

한국산 개로부터 Isospornohioenis를 분리하기 위하여 형태학적 특성을 관찰하였던 바 다음과 같은 결과를 얻었다. 즉, 전북지방의 개의 분편에서 검출된 Isospora spp. 중 I. ohioensis의 oocyst 하나를 분리하여 강아지에 경구감염시켜 얻은 oocyst를 다시 5두의 개에 감염시킨 후 형태학적 특성을 현미경하에서 관제하였다. 이의 잠복기는 4일이었으며 분편내에 배출된 oocyst의 크기는 $22.9{\;}{\times}{\;}19.8{\;}\mu\textrm{m}$ (R = 1.16)이었고 sporont의 크기는 $17 4{\;}{\times}{\;}16.3{\;}\mu\textrm{m}$ (R = 1.06)이었다. 96시간에 있어서 포자가 완전히 형성되었으며 oocyst 및 sporocyst의 크기는 각각 $22.8{\;}{\times}{\;}20.5{\;}\mu\textrm{m}$ (R = 1.11)과 $15.0{\;}{\times}{\;}10.8{\;}\mu\textrm{m}$ (R = 1.39)이었다. 포자형성 후에 oocyst 및 sporocyst의 크기는 거의 변화가 없었던 점으로 보아 개의 분편검사를 통한 Isosporc속의 감별진단을 위하여 96시간 정도의 포자형성기문이 필요할 것으로 예상되는 바이다.

• 한국식물병리학회지
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• 제14권4호
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• pp.325-330
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• 1998

On the basis of the fact that the pycnidiospore of Botryosphaeria dothidea, the causal fungus of apple white rot is a typical water borne spore, a method for quantitative analysis of pycnidiospore dispersal from the warts produced on the diseased apple tree stem was developed. The warts on which cracks developed either on or around them were cut off at the base, and shaked in the water for 4hours at 2$0^{\circ}C$, in which condition the maximum number of spores were released. The volume of shaking solution was calculated as 1 ml per one wart. At the end of shaking, Trio, a household detergent was added to the shaking solution to the concentration of 0.1%, and shaked for additional 10 minutes at 35$^{\circ}C$ to take off the spores attached on the glass ware. One milliliter of the spore suspension thus prepared were passed through transparent membrane filter (pore size : 3.0 ${\mu}{\textrm}{m}$), and the spores attached on the filter were counted under a microscope ($\times$200) after staining them with lactophenol supplemented with aniline blue. The results thus obtained were statistically consistent when at least 30 warts were used simultaneously in single shaking. This method can be applicable in the elucidation of ecology of sporulation and spore dispersal, and also in the screening of the sporulation inhibitor which can be used in the control of the disease by reducing the inoculum density.