• 한국균학회지
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• 제20권2호
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• pp.134-143
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• 1992

내생균근 2속 4종 (Scutellospora heterogama, Sc. verucosa, Sc. calospora, Gigaspora magarita)의 포자가 분포한 토양을 채집하여 Pots를 구성하고 그 토양내 환경(거름의 종류와 농도)을 달리하여 숙주식물(수수)을 키우면서 시간별 포자수 증가 상태와 식물 성장도를 조사하였다. 그 결과 포자수 증가면에 있어서 최고 4배이상의 증가치를 관찰하였고 포자종에 따라서는 5배 이상의 포자수 증가를 볼 수 있었다. 그리고 포자증가치가 가장높게 나타나는 시기는 종간, 인산의 농도간에 약간의 차이는 있었으나 대개 30-40일경에 나타났고 이러한 높은 포자증식 상태가 주기적 경향을 띰을 볼 수 있었다. 또한 숙주식물의 생체량은 거름의 종류에 따라 2-3배 이상의 성장도 차이를 나타내는 경우가 있었으나 전체 포자수 증가에 있어서는 별차이가 없었으며 오히려 감소된 경향을 관찰할 수 있었다.

• 미생물학회지
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• 제31권3호
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• pp.218-223
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• 1993

Conditions for the release and regeneration of protoplasts form Rhizopus oryzae and intergeneric protoplast fusion between Rhizopus oryzae and Aspergillus oryzae were studied. High yields of protoplast fusion between Rhizopus oryzae and Aspergillus oxyzae were studied. High yield of protoplasts from young germilings of R. oryzae were obtained by using lytic enzymes containing chitosanase (3 mg/ml), chitinase (3 mg/ml) and Novozym 234 (5 mg/ml). 0.5M glucose was used as the osmotic stabilizer and optimum pH of buffer was determined to be pH 7.5-8.0. Under these conditions, protoplasts were formed after about 3-4 hrs incubation. Approximately, 1.0%-4.9% of these protoplasts were formed after about 3-4 hrs incubation. Approximately, 1.0%-4.9% of these protoplasts regenerated on solid medium with a soft agar overlay. We have also carried out protoplasts fusion between R. oryzae and A. oryzae and have succeeded in obtaining three types of intergeneric fusants. In these experiments, 35% PEG-4000 and 10 mM CaCl$_{2}$ were used as fsogenic agents, and auxotrophic properties were used as a genetic marker to select fusants. Complementation frequency be protoplasts fusion of A. oxyzae and R. oryzae was 4.4% * 10$^{-5}$ . The fusant strains of the first type were prototrophs showing an Aspergillus type morphology with dark-yellow sporulation, those of the second type were also Apergillus type morphology but showed no sporulation. And the strains of the third type stopped growing when fusion products grown on regeneration minimal medium were transferred to fresh minimal medium. The formation of fusion products was observed by fluorescent vital stains for complementary labelling of protoplats from R. oryzae and A. oryzae. Rhodamine 6G and fluorescein diacetate wer useful complementary vital stains of Rhizopus and Aspergillus protoplasts for visualization of requency and type (dicell, multicell) of fusion.

• 식물병과 농업
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• 제5권1호
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• pp.20-26
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• 1999

Ultraviolet light is required for the sporulation of Didymella bryoniae, a gummy stem blight fungus in cucurbits such as watermelon, melon, oriental melon, cucumber and pumpkin. In this experiment, the upper limit of wave length for the production of pycnidia of D. bryoniae was 365 nm - 375 nm. Two plastic houses were covered with either common transparent film (wave length longer than 225 nm is transmitted) or UV-absorbing film ( wave lenght shorter than 388 nm is absorbed). In both houses, seedlings inoculated with D. bryoniae were placed in the center of the house at 30 days after transplantation of watermelon (cv. Whanhoseong), and the disease incidences between the houses were compared until 80 days after transplantation. The number of disease lesions and incidence of pycnidia-producing lesions under the UV-absorbing film were reduced by 90% and 80%, respectively, compared to the common transparent film. The internode lengths of plants grown in the two houses were not significantly different, but the plants grown under the UV-absorbing film had longer vines and more leaves than plants under the common transparent film. However, fruit characters such as weight, length, width, rind thick and brix, were not different between the two houses. Occurrence of aphids was reduced in the UV-absorbing film, but those of mites or diseases (powdery mildew and sooty mold) were not different between the houses. These results suggest that disease incidence of gummy stem blight of watermelon in the greenhouse can be controlled by the use of UV-absorbing film.

• The Plant Pathology Journal
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• 제36권4호
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• pp.314-322
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• 2020

Interplay between histone acetylation and deacetylation is one of the key components in epigenetic regulation of transcription. Here we report the requirement of MoHDA1-mediated histone deacetylation during asexual development and pathogenesis for the rice blast fungus, Magnaporthe oryzae. Structural similarity and phylogenetic analysis suggested that MoHDA1 is an ortholog of Saccharomyces cerevisiae Hda1, which is a representative member of class II histone deacetylases. Targeted deletion of MoHDA1 caused a little decrease in radial growth and large reduction in asexual sporulation. Comparison of acetylation levels for H3K9 and H3K14 showed that lack of MoHDA1 gene led to significant increase in H3K9 and H3K14 acetylation level, compared to the wild-type and complementation strain, confirming that it is a bona fide histone deacetylase. Expression analysis on some of the key genes involved in asexual reproduction under sporulation-promoting condition showed almost no differences among strains, except for MoCON6 gene, which was up-regulated more than 6-fold in the mutant than wild-type. Although the deletion mutant displayed little defects in germination and subsequent appressorium formation, the mutant was compromised in its ability to cause disease. Wound-inoculation showed that the mutant is impaired in invasive growth as well. We found that the mutant was defective in appressorium-mediated penetration of host, but did not lose the ability to grow on the media containing H₂O₂. Taken together, our data suggest that MoHDA1-dependent histone deacetylation is important for efficient asexual development and infection of host plants in M. oryzae.

• Journal of Microbiology and Biotechnology
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• 제2권3호
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• pp.189-196
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• 1992

A $\alpha$-l, 4-D-glucan maltohydrolase $(\beta$-amylase), secreted by the mesophilic aerobic bacterium Bacillus polymyxa No.26, was purified and characterized. The enzyme production was increased after a logarithmic phase of bacterial growth and paralleled with the onset of bacterial sporulation. By applying anion exchange chromatography and gel filtration the enzyme was purified 16.7-fold and had a specific activity of 285.7 units/mg. Two enzyme activities were eluted on a column of DEAE-Sephadex chromatography, and they were designated as E-I for a major enzyme peak and E-II for a minor peak. Of them, E-I enzyme peak was further purified by using gel chromatography. The molecular mass of this enzyme was determined to be 64, 000 daltons and consisted of a single subunit, showing an isoelectric point of 8.9. The enzyme was able to attack specifically the $\alpha$-l, 4-glycosidic linkages in soluble starch and caused its complete hydrolysis to maltose and $\beta$-limited dextrin. This amylolytic enzyme displayed a temperature optimum at $45^\circ{C}$ and a pH optimum at 7.0. The amino acid composition of the purified enzyme was quite similar to the other bacterial $\beta$-amylases reported. Surprisingly, the purified enzyme from this aerobe only exhibited hydrolytic activity on soluble starch, not on starch granules. The degradation of from starch by $\beta$-amylase was greatly stimulated by pullulanase addition. These results differentiated from other $\beta$-amylases reported. Based on a previous result that showed the enzyme system involves in effective degradation of raw starch granules, this result strongly suggested that the purified enzyme (E-I) can be a synergistic part of starch granule-digestion and E-II plays a crucial role in digestion of starch granules.

• The Plant Pathology Journal
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• 제19권2호
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• pp.92-96
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• 2003

The study was conducted to determine the cultural conditions and the effect of inert fillers for melanization and sporulation abilities of sodium alginate pellets, and the weeding efficacy of the formula in the field. Melanin production of E. nematosporus was affected by striking frequency. Percentage of melanized beads was increased to 80.6% at higher rpm up to 180. The melanized pellets produced more conidia with abundant mucilage than unmelanized pellets. Shaker culture of Epicoccosorus nematosporus with sodium alginate yielded a total of 55 mg per 100 pellets. Percentage of melanized pellets was highest with 81.0% and 83.3% of melanization, when wheat bran and rice polish were amended and produced the conidia with 65.4 and 68.4 mg per 100 pellets, respectively. When 1 L of conidial suspension of 6.0$\times$$10^5$ conidia per ml was applied on 30-day-old plants in a plot, 74.5% of the plants were killed within 20 days, whereas, its melanized sodium alginate pellets killed 57.8% of the plants in the same period. The number of tuber formation of Eleocharis kuroguwai in the untreated control plots was 128.5 per plot, but those of the plots treated with conidial suspension and melanized pellets were 22.1 and 39.7, respectively, at the end of the season. Results of this study showed that melanization of mycelia-mixed sodium alginate are an important sporulation factor in E. namatosporus as a mycoherbicide.

• 한국균학회지
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• 제14권1호
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• pp.71-78
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• 1986

사과 반점낙엽병균(斑點落葉病菌) Alternaria mali의 단포자분리(單胞子分離) 1,200균주(菌株)는 captafol, chlorothalonil 및 folpet 100,000 ${\mu}g/ml$에서 각각 76, 96, 및 15% 그리고 iprodione및 polyoxin 10,000 ${\mu}g/ml$에서 5 및 3%의 균사생장(菌絲生長)을 보였다. 이들 내균성(耐菌性)은 상기(上記) 살균제간(殺菌劑間) 그리고 captan, garbenda, 및 thiophanate methyl에 대하여서도 균사생장(菌絲生長) 교차내성(交差耐性) 또는 포자형성(胞子形成) 교차내성(交差耐性)이 높았다. captafol, mancozeb, polydong 및 propineb는 농가사용권장농도 이하(以下)인 100 ${\mu}g/ml$에서도 포자발아(胞子發芽) 억제효과(抑制效果)가 거의 완전하여 포자발아(胞子發芽) 교차내성(交差耐性)을 보이지 않았다. benomyl, fenarimol, oxidong, 및 triademefon을 중도(中度)의 균사생장(菌絲生長), 포자형성(胞子形成) 또는 포자발아(胞子發芽) 교차내성(交差耐性)을 보였다.

• Journal of Microbiology and Biotechnology
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• 제21권9호
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• pp.979-987
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• 2011

Culture pH change has some important roles in signal transduction and secondary metabolism. We have already reported that acidic pH shock enhanced actinorhodin production in Streptomyces coelicolor. Among many potential governing factors on pH variation, the putative $Na^+/H^+$ antiporter (sha) genes in S. coelicolor have been investigated in this study to elucidate the association of the sha on pH variation and secondary metabolism. Through the transcriptional analysis and overexpression experiments on 8 sha genes, we observed that most of the sha expressions were promoted by pH shock, and in the opposite way the pH changes and actinorhodin production were enhanced by the overexpression of each sha. We also confirmed that sha8 especially has a main role in maintaining cell viability and pH homeostasis through $Na^+$ extrusion, in salt effect experiment under the alkaline medium condition by deleting sha8. Moreover, this gene was observed to have a function of pH recovery after pH variation such as the pH shock, being able to cause the sporulation. However, actinorhodin production was not induced by the only pH recovery. The sha8 gene could confer on the host cell the ability to recover pH to the neutral level after pH variation like a pH drop. Sporulation was closely associated with this pH recovery caused by the action of sha8, whereas actinorhodin production was not due to such pH variation patterns alone.

• 한국응용곤충학회지
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• 제21권3호
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• pp.128-132
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• 1982

봄보리 1.5엽기에 흰가루 병균을 접종하여 병진전에 따른 엽내전분함량변화를 측정하였다. 1.5엽기에 접종하였을 때 감수성 품종 Peruvian과 성체식물저항성 품종 Asse에서 상이한 전분축적양상을 보였다. 감염초기에서는 두 품종 모두 전분함량에 다소 변화가 있었다. 병반형성과 포자형성 동안 감수성 품종 Peruvian에서 전분함량감소가 뚜렷하였으나 Asse에서는 병반형성 동안 증가하였고 세포형성전후에 급격히 감소하였다. 감염이 심한 1.5엽에서 Peruvian은 급격한 전분감소를 보였으나 Asse는 감염강도에 관계없이 감염잎에 높은 전분함량을 유지하였다. 봄 보리의 성체식물저항성과 연관시켜 상이한 발육시기에서 흰가루병 감염된 잎의 전분축적역할을 논하였다.

• 한국균학회지
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• 제17권4호
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• pp.189-193
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• 1989

영지(靈芝)버섯 균사의 비자실체성(非子實體注) 담자포자(擔子胞子)의 형성(形成)에 미치는 광(光)의 영향을 구명(究明)하기 위하여 광질(光質), 광도(光度) 및 광조사(光照射) 시간(時間)을 달리하여 실험하였다. 영지(靈芝)버섯 균사의 비자실체성(非子實體注) 담자포자(擔子胞子)의 형성(形成)에 있어서 광(光)은 필수 요인이었다. 광(光)의 조사(照射)는 16시간 광(光)/8시간 암(暗)으로 계속 처리할 때 포자(胞子)의 형성량(形成量)이 가장 많았고 유효(有效)한 광(光)은 blue와 yellow이었으며 Near U.V.에서는 포자(胞子)가 형성(形成)되지 않았다. 광도(光度)는 백색광으로 1,000Lux일 때 가장 효과적(效果的)이었다. 광형태(光形態) 형성(形成) 반응(反應)은 계통간(系統間)에 명확한 차이를 보여 광(光) 요구성(要求性)이 유전인자(遺傳因子)의 지배를 받음을 보였다.