• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.288.1-288
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• 1995

No Abstract, See Full Text

• 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.

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.204-211
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• 2015

A bacterial strain capable of hydrolyzing xylan and locust bean gum (LBG) was isolated from the Saemangeum tideland of Korea. Based on the biochemical properties and the 16S rRNA gene sequence, the isolate YB-30 was identified as Bacillus subtilis. Xylanase productivity was increased effectively when B. subtilis YB-30 was grown in the presence of wheat bran, while mannanase productivity was increased drastically when grown in the presence of konjac or LBG. Particularly, maximum mannanase and xylanase activities were detected in the culture filtrate of media containing 3.5% konjac and 1% wheat bran. Both enzyme productivities reached maximum levels in the stationary growth phase. The culture filtrate exhibited the highest activity at 60℃ and pH 6.0 for mannanase and at 55℃ and pH 5.5 for xylanase, respectively. Both enzymes were not stable at high temperatures and xylanase was less stable than mannanase. In addition, wheat bran was hydrolyzed to liberate reducing sugar to a greater extent than rice bran by the culture filtrate because the wheat bran contained more arabinoxylan than the rice bran. Hence, xylanase and mannanase produced by B. subtilis YB-30 have a potential use as feed additive enzymes.

• Journal of Life Science
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• v.14 no.3
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• pp.467-471
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• 2004

Bacillus sp. SD-10 was investigated to develope biological pesticides for control of mushroom diseases. Bacillus sp. SD-10 showed high antifungal activity when cultured at 35∼4$0^{\circ}C$ for 30∼4$0^{\circ}C$. The culture filtrate of the bacterium inhibited the growth of mycelium of T. virens which is a kind of mushroom pathogene. On the test of inhibition of spore germination of T. virens, more than 5% of the culture filtrate in the media inhibited completely the germination of the spores. An antimicrobial substance, UPX-1 was purified from the culture filtrate of the Bacillus. From the $^1H$-NMR and $^{13}C$-NMR spectrum analysis, the substance was indentifed as disaccharide composed to six carbon sugars. UPX-1 has not only strong antifungal activity against T. virens but also antibacterial activity against Pseudomonas tolaassi.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.397-400
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• 2010

The activities of mannanase, ${\beta}$-mannosidase, and ${\alpha}$-galactosidase were detected in culture filtrate of Paenibacillus woosongensis showing mannanolytic activity for locust bean gum. Optimal conditions occurred at pH 5.5 and $60^{\circ}C$ for mannanase toward locust bean gum, pH 6.5 and $50^{\circ}C$ for ${\beta}$-mannosidase toward para-nitrophenyl-${\beta}$-D-mannopyranoside, and pH 6.0-6.5 and $50^{\circ}C$ for ${\alpha}$-galactosidase toward para-nitrophenyl-${\alpha}$-D-galactopyranoside in the culture filtrate, respectively. The mannanolytic enzyme of culture filtrate hydrolyzed mannobiose as well as manno-oligosaccharides including mannotriose, mannotetraose, mannopentaose and mannohexaose. It could also hydrolyze ${\alpha}$-1,6 linked galacto-oligosaccharides such as melibiose, raffinose and stachyose to liberate galactose residue. From these results, it is assumed that P. woosongensis produces three enzymes required for the complete decomposition of galactomannan.

• Journal of Life Science
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• v.9 no.1
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• pp.8-14
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• 1999

The growth rate of the A252 strain was increased in tryptic soy broth (TSB) and malt extract-yeast extract medium (ISP-2), but the antifungal activity of culture filtrate was efficient in the media of TSB and nutrient broth. The mycelial growth and the antifungal activity of culture filtrate in TSB medium were optimized at $25^{\circ}C$ and pH 6.5. The growth in 2$\%$TSB concentration was more effective than 1$\%$, but there was no difference of the antifungal activity by the TSB concentrations. The mycelial growth of A252 strain reached to maximum at 72 hr after inoculation, whereas the antifungal activity of culture filtrate was shown to have the highest level at idiophase (60 hr) after inoculation and was decreased a little after 96 hr incubation. The antifungal activity was stable in the pH range of 4 to 11 and evenly at $121^{\circ}C$. The A252 strain was characterized as Streptomyces species by the physiological properties and examination of sporophore me morphology.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1510-1515
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• 2014

Lysobacter capsici YS1215 isolated from soil previously showed nematicidal potential for biological control of the root-knot nematode. In this study, lactic acid, a nematicidal compound, was isolated from culture filtrate of YS1215, and its ovicidal activity was investigated. Purification and identification of lactic acid were performed by a series of column chromatographies and identified by $^1H$ and $^{13}C$ NMR spectra and GC-MS analysis. Our results showed that bacterial culture filtrate containing lactic acid significantly inhibited egg hatching. The lowest egg hatch rate (5.9%) was found at a high concentration ($25 {\mu}l/ml$) of lactic acid at 5 days after incubation, followed by 20 (15.2%), 15 (23.7%), 10 (29.8%), and $5(36.4%){\mu}l/ml$, while egg hatching in the control (sterile distilled water) was 44.5%. This is the first report of lactic acid as an ovicidal compound, and it may be considered as an alternative of chemical pesticide against root-knot nematodes.

• The Korean Journal of Mycology
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• v.12 no.4
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• pp.129-132
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• 1984

To find antitumor constituents in Korean basidiomycetes, the mycelia of Lentinus edodes DMC7, which had shown a good mycelial growth in shakeflasks, were cultured at $27^{\circ}C$ on an orbital shaking incubator at 180 rev/min for 12 days. The medium was composed of glucose (50g/l), yeast extract (9g/l), peptone (9g/l), and seven inorganic salts. A water soluble macromolecular fraction, LF-3, was obtained from the culure filtrate by fractionation with ethanol and dialysis using a Visking tube. When LF-3 was administered i.p. at 50mg/kg/day once daily for 10 consecutive days to female ICR mice which were implanted s.c. with sarcoma 180 $(10^6\;cells/mouse)$, it exerted a highly significant antitumor activity, with the tumor inhibition ratio of 53. 1%.

• Journal of Microbiology and Biotechnology
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• v.31 no.11
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• pp.1526-1532
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• 2021

Suaeda australis, Phragmites australis, Suaeda maritima, Suaeda glauca Bunge, and Limonium tetragonum in the Seocheon salt marsh on the west coast of the Korean Penincula were sampled in order to identify the endophytes inhabiting the roots. A total of 128 endophytic fungal isolates belonging to 31 different genera were identified using the fungal internal transcribed spacer (ITS) regions and the 5.8S ribosomal RNA gene. Fusarium, Paraconiothyrium and Alternaria were the most commonly isolated genera in the plant root samples. Various diversity indicators were used to assess the diversity of the isolated fungi. Pure cultures containing each of the 128 endophytic fungi, respectively, were tested for the plant growth-promoting abilities of the fungus on Waito-C rice germinals. The culture filtrate of the isolate Lt-1-3-3 significantly increased the growth of shoots compared to the shoots treated with the control. Lt-1-3-3 culture filtrate was analyzed and showed the presence of gibberellins (GA₁ 2.487 ng/ml, GA₃ 2.592 ng/ml, GA₉ 3.998, and GA₂₄ 6.191 ng/ml). The culture filtrate from the Lt-1-3-3 fungal isolate produced greater amounts of GA₉ and GA₂₄ than the wild-type Gibberella fujikuroi, a fungus known to produce large amounts of gibberellins. By the molecular analysis, fungal isolate Lt-1-3-3 was identified as Gibberella intermedia, with 100% similarity.

• Microbiology and Biotechnology Letters
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• v.41 no.4
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• pp.398-406
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• 2013

For the maximal production of aphicidal metabolites produced by the Beauveria bassiana Bb08, statistical methods such as the Box-Behnken experimental design and response surface methodology were used. The fungal culture filtrate was sprayed towards 3-star aphids and the mortality was examined. After the statistical analysis of the aphid mortality, the optimal culture conditions were found to be a culture temperature of $26.2^{\circ}C$, medium pH 5.9, flask shaking speed of 209.0 rpm, and culture time of 5.9 days. The expected mortality on days 4, 5, and 6 after spraying the filtrate on to the aphids were 76.8%, 84.9%, and 89.4%, respectively. All 4 factors of the culture conditions significantly affected the production of the aphicidal metabolites, and the order of significance was temperature, pH, culture time and shaking speed.