• Journal of Korean Society of Forest Science
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• v.79 no.2
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• pp.216-221
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• 1990

Vegetational data from Mt. Gyeryong and Deokyu in central Korea were analysed in relation to 15 environmental variables. Two multivariate methods were applied : two-way indicator species analysis (TWINSPAN) for classification and detrended canonical correspondence analysis(DCCA), a recent technique which extracts ordination axes that can be related to environmental factors. The relationship between the distribution of dominant species of forest vegetation and soil condition in Mt. Gyeryong and Deokyu was investigated by analyzing elevation and soil nutrition gradient. Quercus mongolica forest was distributed in the high elevation and good nutrition area, Carpinzrs laxiflora and Fraxinus rhynclzophylla forest in the medium elevation and good nutrition area, Piszus densiflora-Quercus mongolica and Quercus variabilis forest in the medium elevation and medium nutrition area, Styrax jabozaica forest in the low elevation and medium nutrition area, and Pinus densiflora forest in the low elevation and poor nutrition area. The dominant compositional gradient related to elevation.

• Journal of Microbiology and Biotechnology
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• v.21 no.6
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• pp.574-581
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• 2011

A Gram-positive bacterium was isolated from the saline soils of Jangpura (U.P.), India, and showed high-level of radiation-resistant property and survived upto 12.5 kGy dose of gamma radiation. The 16S rDNA sequence of this strain was examined, identified as Bacillus sp. strain HKG 112, and was submitted to the NCBI GenBank (Accession No. GQ925432). The mechanism of radiation resistance and gene level expression were examined by proteomic analysis of whole-cell extract. Two proteins, 38 kDa and 86.5 kDa excised from SDS-PAGE, which showed more significant changes after radiation exposure, were identified by MALDI-TOF as being flagellin and S-layer protein, respectively. Twenty selected 2-DE protein spots from the crude extracts of Bacillus sp. HKG 112, excised from 2- DE, were identified by liquid chromatography mass spectrometry (LC-MS) out of which 16 spots showed significant changes after radiation exposure and might be responsible for the radiation resistance property. Our results suggest that the different responses of some genes under radiation for the expression of radiation-dependent proteins could contribute to a physiological advantage and would be a significant initial step towards a fullsystem understanding of the radiation stress protection mechanisms of bacteria in different environments.

• Journal of Crop Science and Biotechnology
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• v.11 no.1
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• pp.45-50
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• 2008

Lignans and neolignans are optically active plant secondary metabolites. Research on biosynthesis of lignans has already been advanced especially for the formation of (+) pinoresinol but information on the biosynthesis of 8-O-4'- neolignans is still limited. Moreover, the chemical structure(position of substituents on aromatic rings) and stereochemistry of 8-O-4' neolignans is not clear. Katayama and Kado discovered that incubation of cell-free extracts from E. ulmoides with coniferyl alcohol in the presence of hydrogen peroxide gave (+)-erythro- and (-)-threo- guaiacylglycerol 8-O-4'-(coniferyl alcohol) ether (GGCE)(diastereomeric ratio, 3:2) which is the first report on enzymatic formation of optically active -8-O-4' neolignans from an achiral monolignol. In this aspect, enzymatic formation of guaiacyl 8-O-4' neolignan is noteworthy to clarify its stereochemistry from incubation of coniferyl alcohol with enzyme prepared from Eucommia ulmoides. In this experiment, soluble and insoluble enzymes prepared from E. ulmoides were incubated with 30 mM coniferyl alcohol(CA) for 60 min. The enzyme catalyzed GGCE, dehydrodiconiferyl alcohol(DHCA), and pinoresinol identified by reversed phase HPLC. Consequently, diastereomeric compositions of GGCE were determined as erythro and threo isomer. Enantiomeric composition was determined by the chiral column HPLC. Both enzyme preparations enantioselectively formed (-)-erythro, (+)-erythro and (+)-threo, (-)-threo-GGCEs respectively.

• Journal of Microbiology and Biotechnology
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• v.13 no.1
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• pp.50-56
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• 2003

A freshwater bloom-forming cyanobacterium, Microcystis aeruginosa, and local soil isolate Scytonema sp. strain BT 23 were demonstrated to contain biotoxic secondary metabolites with pesticidal and mosquito larvicidal activities. A purified toxic constituent from M aeruginosa showed an absorption maximum at 230 nm and its toxicity symptoms, Rf value on TLC, and retention time observed ill an HPLC analysis were similar to those of the hepatotoxic heptapeptide microcystin-LR. The bioactive constituent of the Scytonema sp. was less polar in nature and exhibited two peaks at 240 and 285 m. When applied to two cruciffrous pests, Pieris brassicae and Plutella flostella, the crude extracts and toxic principles from the two cyanobacteria showed significant antifeedant activity in a no-choice bioassay, and at higher concenuations exhibited contact toxicity to the insect larvae. The purified toxin from M. aeruginosa was found to be more effective and produced 97.5 and $92.8\%$ larval mortality in the two pests, fo11owing 2 h of toxin treatment at a concentration of $25{\mu}g$ Per leaf disc (2.5 cm dia.). Meanwhile, similar treatment with the purified toxin from Sytonema sp. stain BT 23 only produced 73 and $78\%$ mortality in the two pests. The cyanobacterial constituents also showed significant activity against Culex and Anopheles larvae. The M. aeruginosa toxin ($20{\mu}g\;ml^-1$) caused 98.2 and $88.1\%$ mortality in the Culex and Anopheles larvae, respectively, while the purified toxin from the Sytonema sp. was less toxic and only produced a 96.3 and $91.2\%$ mortality, respectively, at a much higher concentration ($40{\mu}g\;ml^-1$). Accordingly, the current results point to certain hitherto unknown biological properties of cyanobacterial biotoxins.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.2
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• pp.198-203
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• 1993

The cyst of Scrippsiella trochoidea from the surface mud in Masan Bay was germinated in the incubator for the culture. This species was one of dinoflagellates responsible for the early spring bloom in the southern coastal water of Korea. The culture experiments were carried out under the various gradients of environmental factors to know their effects on the population growth of this dinoflagellate. With respect to the effects of environmental factors on the growth, it was proved that the maximum cell growth was occurred at 4,000 lux of light intensity, salinity $30\%0$ and temperature $20^{\circ}C$. When 0.25ml/ml of the filtrates of Skeletonema costatum culture medium and the supernatants of soil extracts were added to growth medium as organic growth stimulants, both materials enhanced the population growth. In the fatty acid composition of S. trochoidea, $C_{16:0}$ was the major component, and $C_{18:0},\;C_{18:1},\;C_{22:0}\;and\;C_{22:1}$ were a minor components.

• KSBB Journal
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• v.25 no.2
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• pp.123-129
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• 2010

An endospore-forming, rod-shaped bacterium was isolated from forest soil samples collected at the Taebaek mountain of Gangwon province, Korea, and taxonomically characterized by physiological, biochemical and phylogenetic methods. Its 16S rRNA sequences showed the maximum similarity of 97% with B. amyloliquefaciens. In addition, the isolate BCNU 2002 was determined to have the ability to produce enzymes such as amylase, protease, gelatinase and catalase. The in vitro antifungal activity of Bacillus sp. BCNU 2002 was also examined against human pathogenic fungi such as Aspergillus niger, Candida albicans, Epidermophyton floccosum, Saccharomyces cerevisiae, Trichophyton mentagrophytes and Trichophyton rubrum. A maximum production level of antifungal substances of Bacillus sp. BCNU 2002 was achieved under aerobic incubation at $28^{\circ}C$ for 7 days in LB broth. BCNU 2002 showed strong antifungal activities against T. mentagrophytes and T. rubrum with the range of percentage inhibition from 56.25 to 63.23%. It was also confirmed that ethylacetate extract of cultured broth showed a strong antifungal activity against A. niger, C. albicans, S. cerevisiae and T. rubrum by agar diffusion method. The peptide fraction also exhibited broad antifungal spectrum against various pathogenic fungi. The minimum inhibitory concentration values for active extracts ranged between 125 ${\mu}g$/mL and 1000 ${\mu}g$/mL.

• Preventive Nutrition and Food Science
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• v.12 no.2
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• pp.79-83
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• 2007

The effects of young radish (YR, yeolmu in Korean) on the induction of apoptosis were examined in AGS human gastric adenocarcinoma cells. The young radish kimchi (YRK) were made of YR cultivated in the soil without (Control YR kimchi: C-YRK) and with 1,818 g/m$^{3}$ sulfur (Sulfur YR kimchi: S-YRK), respectively. Methanol extracts from S-YRK exhibited higher inhibitory effect on the growth of AGS human gastric adenocarcinoma cells in a time dependent-manner compared to C-YRK at the same concentration. 4,6-diamidino-2-phenylindole (DAPI) staining showed that S-YRK induced apoptosis accompanied by the increased Bax but decreased Bcl-2 in mRNA expression. Moreover, S-YRK decreased the levels of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) mRNA expressions. The results suggested that S-YRK cultivated in the presence of sulfur elicited stronger anticancer activity than C-YRK in vitro. Dietary intakes of S-YRK may be beneficial to decrease the risk of cancer.

• Korean Journal of Weed Science
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• v.14 no.1
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• pp.42-48
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• 1994

The toxic compounds of sorghum stem extracts were isolated by different organic solvents and pH, and characterized and quantified in terms of their inhibition of seed germination and seedling growth in Echinochloa colona(L.) Link and radish(Raphanus sativus L.). Sequential partitioning of stem extract with various organic solvents with increasing polarity showed that all fractions of hexane, ethyl ether, methylene chloride, ethyl acetate, and the aqueous remainder inhibited germination and seedling growth in E. colona. Of the five fractions, the ethyl ether fraction had the greatest inhibitory effect on E. colona. Further separation of the ethyl ether fraction at different pH(pH 2-11) showed that phytotoxic compounds were acidic. The result indicates that the phytotoxin present in the stem extract may be nonpolar and acidic.

• Applied Biological Chemistry
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• v.41 no.7
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• pp.496-499
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• 1998

For the production of theobromine from caffeine, 5 strains of bacteria capable of producing theobromine were isolated from soil. Among them, the strain CT-017 showed the best ability of producing theobromine, and was partially identified as a Pseudomonas sp. For the production of theobromine, fructose was the most effective carbon source at an optimum concentration of 5 g/l. The most effective nitrogen source was 5 g/l of beef extracts. And 0.02 g/l of $Fe^{2+}$, 1.0 g/l of threonine were effective for the production of theobromine. The optimum temperature and initial pH were $28^{\circ}C$ and 6.5, respectively. After 23 hr cultivation, 7.98 g/l of theobromine was produced from 15 g/l of caffeine which corresponds to a conversion yield of 53.2%.

• YAKHAK HOEJI
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• v.52 no.3
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• pp.172-175
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• 2008

Stable isotope ratio of carbon and nitrogen ($\delta^{13}C$ & $\delta^{15}N$), and $\Delta^{9}$-tetrahydrocannabinol (THC) contents were measured on 37 Korean cannabis and 10 commercial grade marijuana seized in Korea. Factors influencing on the measured values and their variations were investigated. $\delta^{13}C$ value of cannabis is specified mainly by water availability. Korean cannabis showed relatively low $\delta^{13}C$ values ranging -33.29$\sim$-27.01% (mean=-31.01%), which reflect geographic conditions of Korea where is rainy, especially during summer. $\delta^{15}N$ values, which reflect individual planting conditions, were relatively high up to -0.5$\sim$18.0% (mean=6.44%). It reflects characteristics of Korean cannabis growing wild in forest or cultivated in fertile soil. Tetrahydrocannabinol is the major hallucinogenic compound of cannabis. Ethanol extracts of cannabis leaves were derivatized by N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and the derivatives were analyzed by GC-MS in selected ion monitoring (SIM) mode. THC contents of Korean cannabis ranged 0.11$\sim$4.34% (mean=1.47%), which were relatively low compared with commercial grade marijuana.