• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.890-894
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• 2002

A xylanase-producing Trichoderma strain was isolated from soil. Xylanase from Trichoderma strain SY was purified 21-fold to an apparent homogeneity, with a $17.4\%$ yield. The optimum pH and temperature were determined to be 5.5 and $50^{\circ}C$, respectively, and its molecular weight was 21-kDa by SDS-PAGE. The corresponding gene, named xyl, was cloned by RT-PCR. DNA blot analysis of xyl showed that this gene is present as a single copy. The amino acid sequence of the Xyl protein showed similarity to those of other xylanases derived from various fungi. mRNA of xyl was highly expressed when this fungus was grown on cellulose or xylan as a sole carbon source, but undetectable when grown on sucrose. Extracts of Escherichia coli cells expressing xyl were found to have xylanase activity. It was confirmed that xyl from this isolate encodes xylanase.

• KSBB Journal
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• v.26 no.1
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• pp.19-26
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• 2011

Of the 500 Actinomycetes isolates obtained from soil, one isolate grown on maltose as the sole carbon source produced compound BHK-P19, which inhibited the growth of multiple drug resistant P. aeruginosa 0245. Ultraviolet radiation mutagenesis curtailed production of BHK-P19. Mutation of the BHK-P19 producer using N-methyl-N'-nitro-N-nitroso-guanidine obviated the antibacterial activity to P. aeruginosa 0245, but not towards P. aeruginosa 0225. The mixing of BHK-P19 and BHK-S5 culture extracts inhibited P. aeruginosa 0254, 0225 and 1113. The combined application of BHK-P19 culture extract and Schizandra chinensis Baillon extract inhibited P. aeruginosa 0254, 0225, 0826, 1113, 1378, 1731 and 2492. Use of various concentrations of BHK-P19 culture extract and ampicillin markedly increased antibacterial activity against multi-drug resistant P. aeruginose 1113.

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.51-54
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• 2009

Myxobacteria, Gram-negative soil bacteria, are a well-known producer of bioactive secondary metabolites. Therefore, this study presents a methodological approach for the high-throughput screening of secondary metabolites from 4 wild-type Myxococcus xanthus strains. First, electrospray ionization mass spectrometry (ESI-MS) was performed using extracellular crude extracts. As a result, 22 metabolite peaks were detected, and the metabolite profiling was then conducted using the m/z value, retention time, and MS/MS fragmentation pattern analyses. Among the peaks, one unknown compound peak was identified as analogous to the myxalamid A, B, and C series. An analysis of the tandem mass spectrometric fragmentation patterns and HR-MS identified myxalamid K as a new compound derived from M. xanthus. In conclusion, LC-MS/MS-based chemical screening of diverse secondary metabolites would appear to be an effective approach for discovering unknown microbial secondary metabolites.

• Mycobiology
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• v.46 no.1
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• pp.47-51
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• 2018

In the present study, the characterization and properties of silver nanoparticles from Yucca shilerifera leaf extract (AgNPs) were investigated using UV-visible spectroscopic techniques, zeta potential, and dynamic light scattering. The UV-visible spectroscopic analysis showed the absorbance peaked at 460 nm, which indicated the synthesis of silver nanoparticles. The experimental results showed silver nanoparticles had Z-average diameter of 729 nm with lower stability (195.1 mV). Additionally, our dates revealed that AgNPs showed broad spectrum antagonism ($p{\leq}.05$) against Fusarium solani (83.05%) and Macrophomina phaseolina (67.05%) when compared to the control after nine days of incubation. Finally, AgNPs from leaf extracts of Y. shilerifera may be used as an agent of biocontrol of microorganism of importance. However, further studies will be needed to fully understand the agronanotechnological potentialities of AgNPs from Yucca schidigera.

• Journal of Biosystems Engineering
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• v.26 no.5
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• pp.415-422
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• 2001

A seedling pick-up device for vegetable transplanters was developed and its work performance was evaluated at the laboratory. The pick-up device extracts seedlings from a 200-cell tray of seedlings and transfers them to the place where they are to be transplanted into the soil. The device consists of a path generator, pick-up pins and a pin driver. The path generator is a five-bar mechanism comprised of a fixed link, a driving link, a driven link, a connecting link and a slider. The slider is constrained to move along the driven link and a fixed slot of combined straight-line and circular paths. The connecting link joins the driving link and the slider. When the slider moves along the straight-line path of the slot it takes seedlings out from the cell and transfers them to the transplanting hopper when moving along the circular path. A proto-type of the pick-up device was built and tested under the various operational conditions such as age of seedling, approach direction and penetration depth of pins to the cell, holding method of seedling and extracting velocity. The device extracted 30 seedlings per minute with the maximum success ratio of 97% using the seedlings of 23 days old. Some design details were also discussed and suggested to enhance the performance of the device.

• Korean Journal of Microbiology
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• v.29 no.4
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• pp.250-257
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• 1991

An obligate methanol-oxidizing bacterium, Methylobacillus sp. strain SK1, which grows only on methanol was isolated from soil. The isolate was nonmotile Gram-negtive rod. It does not have internal membrane system. The colonies were small, whitish-yellow, and smooth. The guanine plus cytosine content of the DNA was 48 mol%. Cellular fatty acids consisted predominantly of large amounts of straight-chain saturated $C_{16:0}$ acid and unsaturated $C_{16:1}$ acid. The major ubiquinone was Q-8, and Q-10 was present as minor component. The cell was obligately aerobic and exhibited catalase, but no oxidase, activity. Poly-.betha.-hydroxybutyrate, endospores, or cysts were not observed. the isolate could grow only on methanol in mineral medium. Growth factors were not required. The isolate was unable to use methane, formaldehyde, formate, methylamine, and several other organic compounds tested as a sole source of carbon and energy. Growth was optimal at 35.deg.C and pH 7.5. It could not grow at 42.deg.C. The doubling time was 1.2h at 30.deg.C when grown with 1.0%(v/v) methanol. The growth was not affected by antibiotics inhibiting cell wall synthesis and carbon monoxide but was completely suppressed by those inhibiting protein synthesis. Methanol was found to be assimilated through the ribulose monophosphate pathway. Cytochromes of b-, c-, and o- types were found. Cell-free extracts contained a phenazine methosulfate-linked methanol dehydrogenase activity, which required ammonium ions as an activator. Cells harvested after the late exponential phase seemed to contain blue protein.ein.

• Mycobiology
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• v.47 no.3
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• pp.329-334
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• 2019

Streptomyces blastmyceticus strain 12-6 was isolated from a forest soil sample of Cheonan area on the basis of strong antifungal activities against plant pathogenic fungi. Butanol extracts of the cultural filtrates were active against C. acutatum, C. coccodes, C. gloeosporioides, F. oxysporum, and T. roseum. Active fractions were prepared by thin layer chromatography using silica gel plate; 12-6-2 ($R_f$ 0.36), 12-6-3 ($R_f$ 0.44). Scanning electron microscopy showed that the active fractions caused a change in surface texture of fungal spores from smooth surface to wrinkled surface. The lethal effect on the spores of the active fractions varied from 56% to 100%. It was shown that the spores of C. acutatum were more sensitive to the antifungal fractions than the spores of F. oxysporum. Fluorescence staining using TOTO-1 indicated that the antifungal fractions could make the spores more sensitive to the fluorescence dye. Thus, it was suggested that antifungal agents prepared in this study exhibited the antifungal activity by damaging the plasma membrane of both fungal spores and hyphae. Identification of antifungal agents in the active fraction using GC-MS analysis revealed the presence of cyclo-(Leu-Pro) and 9-octadecenamide as major components that have already been known as antifungal substances.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.179-183
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• 1993

A restricted facultatively methanol-oxidizing bacterium, Methylovorus sp. strain SS1, was isolate dfrom soil samples from Kuala Lumpur, Malaysia, through methanol-enrichment culture technique. The isolate was nonmotile Gram-negative rod and did not have complex internal membrane system. The colonies were small, pale-yellow, and raised convex with entire margin. The cell did not produce any spores and capsular materials. The cell was obligately aerobic and exhibited catalase, but no oxidase, activity. Plasmid, carotenoid pigment, and poly-.betha.-hydroxybutyric acid were not found. The guanine plus cytosine content of the DNA was 55%. The isolate was found to grow only on methanol methylamine, or glucose. Growth factors were not required. Cells growing on methanol was found to produce extracellular polysaccharides containing glucose, lactose, and fructose. Growth was optimal (t$_{d}$= 1.7) with 0.5%(v/v) methanol at 40.deg.C and pH 6.5. No Growth was observed at over 60.deg.C. Cell-free extracts of the methanol grown cells exhibited the phenazine methosulfate-linked methanol dehydrogenase activity Methanol was found to be assimilate dthrough the ribulose monophosphate pathway.y.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.79-79
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• 2020

Halophyte is a plant that has evolved to grow well in salty places, and is mainly distributed in coastal wetlands, sand dunes, salt fields, and reclaimed lands in tidal flats and river estuaries. Because it grows in the soil where seawater enters and exits, it is very abound in natural minerals and produces certain metabolites to survive sustainably in the surrounding environment. In this study, anti-inflammatory studies were conducted using 15 kinds of halophyte to secure data on halophytes of infinite value as functional materials. The aim of this study was to select a group of halophytes that regulate iNOS expression, which is involved in the secretion of inflammatory cytokines and nitric oxide production in LPS-induced macrophages. Among the 15 species of halophyte, except for Triglochin maritimum, Suaeda japonica, and Carex pumila, NO production was reduced in 12 species of halophytes, and 7 species of halophyte (Suaeda asparagoides, Artemisia fukudo, Spergularia marina, Aster tripolium, Suaeda australis, Atriplex subcordata, Calystegia soldanella) significantly decreased the expression levels of TNF-α and IL-1β.

• Applied Biological Chemistry
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• v.32 no.3
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• pp.240-248
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• 1989

The effects of the soil properties on the contents of catalpol, sugar and ash in the rhizoma of Ji-whang (Rehmannia glutinosa Lib. var. purpurea Makino) were studied to get information on cultivation for higher quality production. Catalpol contents of the rhizoma of Ji-whang ranged from 3.75 to 4.36%. It was shown that the sand contents of soil was positively correlated with the catalpol contents, and negatively correlated with the contents of fructose and galactose in the rhizoma of Ji-whang. The sand contents of subsoil was also negatively correlated with the contents of ash and acid insoluble ash in rhizoma. The clay contents of subsoil was negatively correlated with the catalpol contents, and positively correlated with the contents of fructose, galactose and sucrose in rhizoma, respectively. The clay contents of soil was positively correlated with the ash contents, and negatively correlated with the contents of ethanol extract and water extract in rhizoma, respectively. The organic matter contents of surface soil and subsoil were negatively correlated with the contents of catalpol and extracts (ethanol and water), and positively correlated with the contents of fructose and ash in rhizoma. The total nitrogen contents of surface soil was negatively correlated with the catalpol contents, and positively correlated with the contents of fructose and sucrose in rhizoma. The potassium contents of soil was highly positively correlated with the fructose contents in rhizoma.