• 미생물학회지
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• 제14권2호
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• pp.47-56
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• 1976

Enzyme activities, such as glucoamylase dextrinogenic amylase, cellulase, acid protase and neutral protease, of Rhizopus isolated from various substrates collected throughout South Korea are measured, and their enzyme activities are surveyed from taxonomical, ecological and physiological viewpoint. Effect of carbon sources and phytohormones on the amylalse production of Rhizopus are also measured. Among the 735 strains of Phizopus isolated, strain number 587 exhibiting most prominent dextrinogenic amylase and netral protease activity is selected as the best strain, and the strain number 673, 108, 329, 165 and 728 are seleted for their predominant cellulase, acid protease, glucoamylase, dextrinogenic amylase and neutral protease activities, respectively. R.acidus and R.nigricans which exhibited relatively higher callulalse activity, showed lower activities for both amylase. R.tritici exhibited higher protease activity. The relations between activities and various substrates of wild strains are not outstnading difference, although the strains isolated from inland region exhibited more or less higher amylase and cellulase activities, than those of coast region, generally. Lactose and dextrin are most effective carbon sources for glucoamylase and dextrinogenic amylase production of the Rhizopus niveus, respectively. Although all phytohormones tested are effective for production of amylase by the Rhizopus strains, except nicotinamide for glucoamylase production, biotin and ascorbate are most effective for dextrinogenic amylase and glucoamylase production, respectively.

• 미생물학회지
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• 제27권4호
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• pp.415-421
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• 1989

Ten strains out of about 1,000 yeast strains isolated from byproducts of alcoholic industries, milk products, fruits, greens, food-related industries and soils of nature, revealed the killer activities. Two strains which have excellent killer activities among them were isolated and identified with Saccharomyces cerevisiae B 15-1 and Hansenula anomala Y 33 by investigation of the morphological, cultural and physiological properties. The optimal conditions on these strains for the production of killer toxin were investigated. The strain B 15-1 showed the highest killer toxin activities when it was cultured up to the log phase of 48 hr in YPD medium (pH 4.7) at $25^{\circ}C$. On the other hand, the strain Y33 revealed the highest activities when it was cultured up to the stationary phase of 60 hr in YPD medium (pH 4.0) at $20^{\circ}C$. The sensitive strain Kyokai 7 was found to be killed entirely by the killer toxin produced from the wild killer yeast B 15-1 when B 15-1 was cocultured with the same cell concentration ($10^{6}$ cells/ml) of Kyokai 7 after cultivation of 36 hr, and with large concentration ($9\times 10^{7}$ cells/ml) after 48 hr.

• Journal of Microbiology
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• 제45권4호
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• pp.364-366
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• 2007

The immunological role of the Pasteurella multocida toxin (PMT) in mice was examined using a PMT mutant strain. After a nasal inoculation, the mutant strain failed to induce interstitial pneumonia. Moreover, PMT had no significant effect on the populations of CD4+, CD8+, CD3+, and CD19+ immunocytes in blood or on the populations of CD4+ and CD8+ splenocytes (P<0.01). However, there was a significant increase in the total number of cells in the BAL samples obtained from the wild-type P. multocida-inoculated mice. On the other hand, the level of IL-l expression decreased when the macrophages from the bronchio-alveolar lavage were stimulated with PMT. Overall, PMT appears to play some role (stimulating and/or inhibiting) in the immunological responses but further studies will be required to confirm this.

• Journal of Microbiology and Biotechnology
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• 제30권12호
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• pp.1944-1949
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• 2020

Mutant sugar transporter ScGAL2-N376F was overexpressed in Kluyveromyces marxianus for efficient utilization of xylose, which is one of the main components of cellulosic biomass. K. marxianus ScGal2_N376F, the ScGAL2-N376F-overexpressing strain, exhibited 47.04 g/l of xylose consumption and 26.55 g/l of xylitol production, as compared to the parental strain (24.68 g/l and 7.03 g/l, respectively) when xylose was used as the sole carbon source. When a mixture of glucose and xylose was used as the carbon source, xylose consumption and xylitol production rates were improved by 195% and 360%, respectively, by K. marxianus ScGal2_N376F. Moreover, the glucose consumption rate was improved by 27% as compared to that in the parental strain. Overexpression of both wild-type ScGAL2 and mutant ScGAL2-N376F showed 48% and 52% enhanced sugar consumption and ethanol production rates, respectively, when a mixture of glucose and galactose was used as the carbon source, which is the main component of marine biomass. As shown in this study, ScGAL2-N376F overexpression can be applied for the efficient production of biofuels or biochemicals from cellulosic or marine biomass.

• 한국식물병리학회지
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• 제13권3호
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• pp.179-183
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• 1997

십자화과 식물에 검은썩음병을 일으키는 Xanthomonas campestris pv. campestris에 대하여 담배 18품종 중 가장 과민반응을 강하게 나타내는 품종(Nicotiana tabacum cv. TC500)을 과민반응 비기주식물로 선발하였다. NTG 돌연변이를 실시하여 얻은 약 4,500개의 mutant들을 $10^{8}$ cells/ml의 농도로 주사 접종하여 비기주식물인 담배 잎에서 과민반응을 유도하지 않는 HR-mutans(XHN 514-774, XHN 620-831)를 선발하였고, 기주식물인 양배추 잎에서 병원성을 나타내지 않는 비병원성변이주(XPN 1001)를 선발하였다. HR mutant를 기주식물인 양배추에 접종한 결과 병원성을 나타내었고, nonpathogenic mutant를 비기주식물인 담배잎에 접종한 결과 과민반응을 유도하였다. 담배 잎에서 HR-mutant와 wild type의 population를 조사한 결과 wild type은 24시간 이후 급격히 감소하는 반면, HR mutant는 일정수준을 유지하였으나 72시간 이후에 감소하였다. 그리고 mutant들의 protease, cellulase, amylase, polygalacturonate lyase 분비여부를 조사한 결과 wild type과 비슷하게 분비하였다.

• Parasites, Hosts and Diseases
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• 제55권2호
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• pp.207-212
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• 2017

Infections of Toxoplasma gondii and Babesia microti are reported in many wild animals worldwide, but information on their incidence and molecular detection in Korean wild fields is limited. In this study, the prevalence of T. gondii and B. microti infection in blood samples of 5 animal species (37 Chinese water deer, 23 raccoon dogs, 6 roe deer, 1 wild boar, and 3 Eurasian badgers) was examined during 2008-2009 in Gangwon-do (Province), the Republic of Korea (=Korea) by using serological and molecular tests. The overall seropositivity of T. gondii was 8.6% (6/70); 10.8% in Chinese water deer, 4.3% in raccoon dogs, and 16.7% in roe deer. PCR revealed only 1 case of T. gondii infection in Chinese water deer, and phylogenic analysis showed that the positive isolate was practically identical to the highly pathogenetic strain type I. In B. microti PCR, the positive rate was 5.7% (4/70), including 2 Chinese water deer and 2 Eurasian badgers. Phylogenetic analysis results of 18S rRNA and the ${\beta}$-tubulin gene showed that all positive isolates were US-type B. microti. To our knowledge, this is the first report of B. microti detected in Chinese water deer and Eurasian badger from Korea. These results indicate a potentially high prevalence of T. gondii and B. microti in wild animals of Gangwon-do, Korea. Furthermore, Chinese water deer might act as a reservoir for parasite infections of domestic animals.

• Journal of Ginseng Research
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• 제39권3호
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• pp.213-220
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• 2015

Background: Korean ginseng (Panax ginseng Meyer) is a perennial herb prone to various root diseases, with Phytophthora cactorum being considered one of the most dreaded pathogens. P. cactorum causes foliar blight and root rot. Although chemical pesticides are available for disease control, attention has been shifted to viable, eco-friendly, and cost-effective biological means such as plant growth-promoting rhizobacteria (PGPR) for control of diseases. Methods: Native Bacillus amyloliquefaciens strain HK34 was isolated from wild ginseng and assessed as a biological control agent for ginseng. Leaves from plants treated with HK34 were analyzed for induced systemic resistance (ISR) against P. cactorum in square plate assay. Treated plants were verified for differential expression of defense-related marker genes using quantitative reverse transcription polymerase chain reaction. Results: A total of 78 native rhizosphere bacilli from wild P. ginseng were isolated. One of the root-associated bacteria identified as B. amyloliquefaciens strain HK34 effectively induced resistance against P. cactorum when applied as soil drench once (99.1% disease control) and as a priming treatment two times in the early stages (83.9% disease control). A similar result was observed in the leaf samples of plants under field conditions, where the percentage of disease control was 85.6%. Significant upregulation of the genes PgPR10, PgPR5, and PgCAT in the leaves of plants treated with HK34 was observed against P. cactorum compared with untreated controls and only pathogen-treated plants. Conclusion: The results of this study indicate HK34 as a potential biocontrol agent eliciting ISR in ginseng against P. cactorum.

• 한국미생물·생명공학회지
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• 제18권5호
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• pp.541-546
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• 1990

Bacillus sphaericus ts-D1290 치사돌연변이주의 특성을 연구하기 위하여 제한온도와 허용온도에서 생산하는 단백질의 차이점을 연구하였고, 모기유충에서 생산하는 단백질을 분리하여 모기유충에 치사되는지를 조사하였다. ts-D1290 균주를 $42^{\circ}C$에서 배양했을 때는 $30^{\circ}C$ 배양보다 균체의 단백질 함량이 약 1/5로 감소하였고, $42^{\circ}C$에서 4시간 배양후 $30^{\circ}C$로 배양하였들 때는 약 1/3로 감소하였다. 그리고 단백질 패천은 ts-D1290 균주를 $42^{\circ}C$에서 전배양 후 $30^{\circ}C$로 하강 배양하였을 때는 $30^{\circ}C$에서 전배야하여 $42^{\circ}C$로 상승배양하였을 때와는 달라 분자량 221kd 단백질이 나타나지 않았지만 분자량 150kd 단백질은 $30^{\circ}C$ 전 배양하였을 때와 같이 현저하게 나타났다.

• 미생물학회지
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• 제23권3호
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• pp.203-208
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• 1985

Bacillu! thuringiensis var. krustaki 3ab k-3의 감온성치사돌연변이체에 대한 생물학적 성상의 변이성의 차이를 조사하고 유전적 특성을 규명하기 위하여 생화학적 성상검사, 항생제에 대한 감수성 조사, 용혈성 검사, 돌연변이체균주의 특수배지에서의 성장비교, Mouse에 대한 치사효과를 $28^{\circ}C$의 허용온도에서 조사하였다. Urease를 생산하지 못하는 돌연변이체는 ts-U154, ts-U601, ts-U602, ts-U603, ts-U604, t-U788 이었다. ts-U603만이 운동성이 상실되었고, ts-U154는 Salicin과 cellobiose을 분해하지 못했고, ribose를 분해하지 않는 균주는 ts-U603였다. 항생제에 대한 반응은 ampicillin, cephalothin, penicillin에는 모두 저항성을 나타냈으나, ts-U154 균주만이 감수성을 나타냈다. Fructus gardenia배지에서 색소를 생산하지 않은 것은 ts-U21, ts-U74, ts-U131과 ts-U154였다 가장 적은 용혈성을 나타내는 균주는 정상형고 ts-U602였고 가장 많은 용혈성을 나타내는 것은 ts-U603 (1:512 x) 이었다. Mouse 에 대한 치사효과는 전혀 없었다.

• 한국버섯학회지
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• 제13권2호
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• pp.92-96
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• 2015

팽이버섯 신품종 '금향'은 '갈뫼'와 수집 야생균주인 'CBMFV-33'으로부터 분리한 단포자를 교배함으로써 육성된 품종으로, 갓 색이 진한 미색을 나타내며, 재배기간이 짧다. 병재배 시 배양 기간은 23일, 초발이 소요일수는 7일, 생육일수는 17일로 총재배기간이 47일이 소요되어 대조품종 '갈뫼'에 비해 7일이 단축되었다. 갓 직경은 '갈뫼'에 비해 크고, 갓 색은 진한 미색을 나타냈다. 수량은 850 ml 병 당 162 g으로 '갈뫼' 대비 8% 증수되었다. 또한 야생 팽이버섯처럼 식미감도 우수하여, 차별화된 색과 맛으로 백색 팽이버섯의 틈새시장 공략에 유리할 것으로 판단된다.