• Biotechnology and Bioprocess Engineering:BBE
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• 제9권3호
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• pp.184-190
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• 2004

The influences of impeller types on morphology and protein expression were investigated in a submerged culture of Aspergillus oryzae. The impeller types strongly affected mycelial morphology and protein production in batch and fed-batch fermentations. Cells that were cultured by propeller agitation grew in the form of a pellet, whereas cells that were cultured by turbine agitation grew in a freely dispersed-hyphal manner and in a clumped form. Pellet-grown cells showed high levels of protein production for both the intracellularly heterologous protein (${\beta}$-glucuronidase) and the extracellularly homologous protein (${\alpha}$-amylase). The feeding mode of the carbon source also influenced the morphological distribution and protein expression in fed-batch fermentation of A. oryzae. Pulsed-feeding mainly showed high protein expression and homogeneous distribution of pellet whereas continuous feeding resulted in less protein expression and heterogeneous distribution with pellet and dispersed-hyphae. The pellet growth with propeller agitation paralleling with the pulsed-feeding of carbon source showed a high level of protein production in the submerged fed-batch fermentation of recombinant A. oryzae.

• The Plant Pathology Journal
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• 제20권3호
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• pp.165-171
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• 2004

A total of 62 isolates of Bipolaris cactivora causing cactus stem rots were isolated from major cactus-growing areas in Korea. Colony morphology of the isolates on potato-dextrose agar was differentiated into aerial (CA) and non-aerial mycelial types (CB). CA had profound aerial mycelium with grayish brown (CA-l), light brownish (CA-2), and brownish (CA-3) pigmentations; respectively, while CB had dark brownish pigmentations. CA had conidia of less dark pigmentation and acute terminal end. CB had darker and more round-end conidia. Twenty-eight amplified fragments were produced by polymerase chain reaction (PCR) with a set of 2 random primers. The sizes of amplified DNA fragments ranged approximately from 0.1 to 2.3 kb. The isolates were classified into 2 major genomic DNA random amplified polymorphic DNA (RAPD) groups at the genomic similarity of 97.7％ and 95.1％, respectively. Cluster analysis of genetic similarity among the isolates generated a dendrogram that clearly separated all isolates into SA or SB. This result suggests that there may be two morphotypes of B. cactivora in Korea that may differ in their genetic constitutes.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.844-851
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• 2010

Controlling the dissolved oxygen (DO) in the fed-batch culture of the medicinal mushroom Ganoderma lucidum led to a 2-fold increase of the maximum biomass productivity compared with uncontrolled DO conditions. By contrast, extracellular polysaccharide (EPS) production was two times higher under oxygen limitation (uncontrolled DO) than under increased oxygen availability (controlled DO). Morphologically, dispersed mycelium was predominant under controlled DO conditions, with highly branched hyphae, consistent with the enhanced culture growth noted under these conditions, whereas in the uncontrolled DO process mycelial clumps were the most common morphology throughout the culture. However, in both cultures, clamp connections were found. This is an exciting new finding, which widens the applicability of this basidiomycete in submerged fermentation. In rheological terms, broths demonstrated shear-thinning behavior with a yield stress under both DO conditions. The flow curves were best described by the Herschel-Bulkley model: flow index down to 0.6 and consistency coefficient up to 0.2 and 0.6 Pa $s^n$ in uncontrolled and controlled cultures DO, respectively. The pseudoplastic behavior was entirely due to the fungal biomass, and not to the presence of EPS (rheological analysis of the filtered broth showed Newtonian behavior). It is clear from this study that dissolved oxygen tension is a critical process parameter that distinctly influences G. lucidum morphology and rheology, affecting the overall performance of the process. This study contributes to an improved understanding of the process physiology of submerged fermentation of G. lucidum.

• Mycobiology
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• 제31권2호
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• pp.81-85
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• 2003

Antifungal properties of methyl 2-benzimidazole carbamate(BMC) were investigated using 16 fungi. Cytotoxicity test of BMC revealed that the morphology of HeLa cells was considerably deformed even at the concentrations as low as 0.1 ppm. Minimum inhibitory concentration(MIC) values of BMC for 7 fungi among the 16 tested ones were lower than $1.95{\times}10^{-4}{\mu}g/ml$, while Aspergillus flavus showed an MIC value higher than 1.0 ${\mu}g/ml$. Tolerance induction against BMC was successful only for Paecilomyces farinosus LAR10, contrary to the expectation that tolerance would be induced for the fungi having high MIC values such as Aspergillus niger ATCC 9642 and A. flavus ATCC 9643. Spore germination of A. niger ATCC 9642 was suppressed by BMC. However the mycelial growth of the fungus once germinated was not retarded at all by BMC up to 8 MIC. Addition of lanosterol provided a remedy for the reduced germination rate of A. niger ATCC 9642 spores.

• Journal of Microbiology and Biotechnology
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• 제24권3호
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• pp.354-358
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• 2014

A screening test showed that lycorine exhibited significant antifungal activity against 24 pathogenic crop fungi at concentrations of 500 ${\mu}g/ml$ and 100 ${\mu}g/ml$, respectively. Fusarium graminearum was selected for antifungal mechanism studies by observing its mycelial morphology and investigating the variations in its conductivity. In addition, the substance absorption and metabolism of F. graminearum were explored. The mechanism was revealed as being one by which lycorine destroyed the cellular membrane and further influenced substance absorption and cell metabolism.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.552-557
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• 2001

By UV-irradiation of Eremothecium ashbyii DTl, a higWy flavinogenic mutant (UV-18-57) and a nonflavinogenic mutant (UV -85) were obtained. The physio-morphological characteristics of these three strains were studied on glucose medium in submerged fermentation. Glucose utilization and mycelial growth occurred in 0 - 2 days of fermentation. By the third day, the biomass had declined. Extracellular riboflavin excretion was distinct from the second day, reaching a maximum rate by the fourth day. The hyphae of the highly flavinogenic mutant UV-18-57 were broader than DTl, while the nonflavinogenic UV-85 hyphae were very thin. Riboflavin accumulation was high in UV-18-57 (extracellular riboflavin,$825\mu\textrm{g}/ml$ , and intracellular, $490\mu\textrm{g}/ml$) and caused the mycelia to swell into bulbous forms. Riboflavin accumulation was less in DTl ($108\mu\textrm{g}/ml$ extracellular and $24\mu\textrm{g}/ml$ intracellular) and correspondingly its hyphae were thinner than those of UV-18-57 and swollen bulbous mycelia were not prominent. UV-85 was nonflavinogenic and, accordingly, its mOlphological characteristics included long thin filaments with no intracellular riboflavin accumulation. A large number of greenish fluorescence spores were seen in UV-18-57, whereas DTI had less spores and UV-85 was nonsporulating. Sporulation is correlated with riboflavin production. UV-18-57 had better mycelial integrity and lysis started only by the seventh day, whereas DTI and UV -85 started to lyze earlier by 4 -5 days. By the late stage of fermentation (eighth day), DTl had a few long, thin filaments indicating some secondary growth, whereas UV -85 showed a compact pellet form of mycelia. Most mycelia of UV-18-57 still appeared intact.

• 한국버섯학회지
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• 제14권3호
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• pp.75-80
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• 2016

국내에서 분리한 신규 P linteus KACC93057P의 자실체의 형태적 특성을 육안적 으로 관찰한 결과 대가없이 기주부착형으로 자실체표면은 단단한 목질형태 (hardy woody) 로 동심원으로 윤층대 (zonate)와 홈을 형성하고 담갈색을 띠고 있었다. 자실체 뒷면 테두리는 진황색, 내부는 담황갈색을 띠며 현미경 미세구조를 관찰한 결과 관공은 원형또는 각진형이며, 관공구는 5-7 per mm크기로 나타났다. hyphal system은 2분지형이며 포자는 $4.5-6{\times}4-5{\mu}m$크기로 난형또는 유구형 담갈색을 띠어 P linteus와 유사한 특성을 보였다. YGMA배지상에서 KACC93057P는 $25-30^{\circ}C$가 최적온도로 균사체 성장률이 장수상황과 고려상황에 비하여 10-25% 높았으며 균사밀도가 다른 균주보다 현저히 높게 나타났다. ITS-rDNA염기서열비교결과 96% 이상의 상동성으로 I. lonicericola, I. linteus, I. baumii와 근연관계를 형성 하였다.

• 한국균학회지
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• 제40권2호
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• pp.93-97
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• 2012

본 연구는 큰느타리버섯(Pleurotus eryngii)에 감마 방사선을 조사하여 형태적, 생리적 특성이 향상된 새로운 큰느타리버섯 품종을 개발하기 위하여 수행되었다. 큰느타리버섯에서 분리한 원형질체에 0.25-1.25 KGy의 감마 방사선을 조사하였다. 원형질체는 YPMGA 배지에서 80%의 치사율을 나타냈고 이들 중 무작위로 500개의 변이체를 선발하여 PDA 배지에 배양하였다. 그 결과, 대부분의 변이체가 대조구와 비슷한 형태와 생장률을 나타냈으며, 이 중 100개의 변이체가 대조구와 약간의 차이를 보였다. 67개 변이체에 대해 cellulase 활성과 laccase 활성을 조사하였다. 그 결과, 대체적으로 대조구와 유사한 효소 활성을 나타내었고, 5개의 변이체가 대조구에 비해 더 높은 cellulase 활성을 나타내었다. 또한 감마 방사선 조사 변이체의 유전적 변이를 조사하기 위하여 UFPF-PCR을 이용하여 다형성을 조사하였다.

• 생명과학회지
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• 제9권1호
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• pp.8-14
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• 1999

A252 균주의 항균성물질의 생성 및 균주의 배양적 특성을 조사한 결과 균체의 생장은 TSB와 malt extract-yeast extract (ISP-2) 배양기가 좋았으며, 배양여액의 항균활성은 TSB와 nutrient broth에서 효과적이였다. TSB 배지에서 균사생장 및 배양여액의 항균활성은 $25^{\circ}C$와 pH 6.5에서 최적화 되었으며, 2$\%$ TSB 농도에서는 1$\%$에 비해 생장은 좋았으나 배양여액의 항균활성에는 차이가 없었다. A252 균주의 균사 생장은 접종 72시간 후에 최대치에 달하였으며 반면 배양액의 항균력은 접종 60시간 후인 idiophase에 가장 높은 수준을 보였지만 96시간 후에는 약간 감소하는 경향을 나타냈다. 배양여액의 항균활성은 $121^{\circ}C$ 고온에서도 안정하였으며, pH에 대한 안정성은 4.0 - 9.0의 범위였다. A252 균주의 생리적 특성 및 분생자경의 형태 등을 관찰한 결과 Streptomyces sp.로 동정되었다.

• 미생물학회지
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• 제41권4호
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• pp.246-254
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• 2005

Neurospora crassa의 게놈 분석을 통하며 tetratricopeptide repeat (TPR) 부위를 보유할 것으로 추정되는 19중의 단배질을 찾아냈다. 이중에서 한 단백질은 Saccharomyces cerevisiae에서 다양한 유전자들의 공통 전사 억제인자로 알려진 Ssn6 단백질에 $60\%$ 이상의 유사도를 보였다. N. crassa의 RIP (repeat-induced point mutation) 과정을 통하여 생산된 돌연변이 균주들은 도두 느리게 성장하였는데, 4가지로 구분되는 돌연변이 표현형을 나타냈다. 첫 번째 돌연변이 표현형은 균사가 ropy돌연변이와 유사한 균사 모양으로 성장하고 밀도가 높아 보였고, 대분생포자는 yellow와 csp 표현형을 보였다. 두 번째 돌연변이형은 늦은 성장을 보였지만 대분생포자를 생산하였다. 세 번째는 매우 느린 균사 성장을 보였고 acon 표현형을 나타냈다. 마지막 돌연변이형은 거의 공기 중으로 균사를 뻗지 못하였으며 acon 표현형을 보였는데, rco-1 RIP 돌연변이체와 유사하였다. 돌연변이체들은 모두 male로서는 수정능을 보였지만 female로서는 교배가 불가능했으며 자낭각을 생산하지 못하였다. 이 결과들은 이 유전자가 N. crassa의 성장은 물론 무성생식 및 유성생식의 여러 과정에 관여함을 나타낸다. 염색체와 cDNA의 서열을 분식한 결과에 따르면, 유전자가 6개의 인트론을 보유하고 있고, 총917개의 아미노산으로 구성된 102kDa의 단백질을 암호화할 것으로 예상되었다. 이 유전자를 rcm-1 (regulation of conidiation and morphology)으로 명명하였다.