• Journal of Species Research
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• v.5 no.1
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• pp.179-187
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• 2016

As a subset investigation to discover indigenous prokaryotic species in Korea, a total of 21 bacterial strains assigned to the class Betaproteobacteria were isolated from a wide range of environmental samples which collected from fresh water, roots of plants, mineral water and soil from ginseng farm. Phylogenetic analysis based on 16S rRNA gene sequences indicated that 21 isolated strains were most closely related to the class Betaproteobacteria, with high 16S rRNA gene sequence similarity (>99.1%) and constructed a robust phylogenetic clade with the closest species in the class Betaproteobacteria. These isolated species have no previous report or publication in Korea; therefore 17 species in 14 genera of 6 families in the order Burkholderiales, 1 species in the order Methylophilales, 2 species in 2 genera of 1 family in the order Neisseriales are reported for betaproteobacterial species found in Korea. Gram reaction, colony and cell morphology, basic biochemical characteristics, isolation source, and strain IDs are also described in the species description section and as an image.

• Parasites, Hosts and Diseases
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• v.44 no.4 s.140
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• pp.321-330
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• 2006

The pathogenic mechanism of granulomatous amebic encephalitis (GAE) and amebic keratitis (AK) by Acanthamoeba has yet to be clarified. Pretense has been recognized to play an important role in the pathogenesis of GAE and AK. In the present study, we have compared specific activity and cytopathic effects (CPE) of purified 33 kDa serine proteinases from Acanthamoeba strains with different degree of virulence (A. healyi OC-3A, A. lugdunensis KA/E2, and A. castelianii Neff). Trophozoites of the 3 strains revealed different degrees of CPE on human corneal epithelial (HCE) cells. The effect was remarkably reduced by adding phenylmethylsulfonylfluoride (PMSF), a serine proteinase inhibitor. This result indicated that PMSF-susceptible proteinase is the main component causing cytopathy to HCE cells by Acanthamoeba. The purified 33 kDa serine proteinase showed strong activity toward HCE cells and extracellular matrix proteins. The purified proteinase from OC-3A, the most virulent strain, demonstrated the highest enzyme activity compared to KA/E2, an ocular isolate, and Neff, a soil isolate. Polyclonal antibodies against the purified 33 kDa serine proteinase inhibit almost completely the proteolytic activity of culture supernatant of Acanthamoeba. In line with these results, the 33 kDa serine proteinase is suggested to play an important role in pathogenesis and to be the main component of virulence factor of Acanthamoeba.

• Microbiology and Biotechnology Letters
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• v.6 no.4
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• pp.149-153
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• 1978

A strain of Streptomyces sp producing chitinase was isolated from soil and its cultural condition and some properties of this enzyme were investigated. When 0.375 per cent of glucose was added to basal medium, this organism produced the most quantities of this enzyme after shaking culture at 3$0^{\circ}C$ for 48 hrs., while the production of the enzyme was repressed at the more concentration of glucose than that. The enzyme had a optimal pH of 7.0, optimal temperature of 5$0^{\circ}C$ and the activity of that was not decreased by heat treatment for 20 minute at 7$0^{\circ}C$. And then the activity was increased by Co$^{2+}$ but was slightly inhibited by Hg$^{2+}$, Ni$^{2+}$, Pb$^{2+}$.EX> 2+/.

• Microbiology and Biotechnology Letters
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• v.2 no.1
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• pp.13-17
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• 1974

A strain of Streptomyces sp. which producing a metal containing proteolytic enzyme was isolated from soil and some properties of this enzyme were investigated. The following results were obtained. 1. Optimal pH and temperature of this enzyme were pH7.0 and 37$^{\circ}C$ 2. This enzyme was easily inactivated with heat treatment: for example, by the treatmentat 37$^{\circ}C$ for 100 minutes the activity of the enzyme was decreased to about 50 per cent of intial actively but this enzyme was stable at neutral pH. 3. The activity of this enzyme was not inhibited by $Mg^{＋＋}$, $_Mn^{＋＋}$, $Ca^{＋＋}$, Pb$^{＋＋}$, or $Ba^{＋＋}$ ect. but strongly inhibited by Hg$^{＋＋}$, Co$^{＋＋}$, Ag$^{＋}$, Cu$^{＋＋}$, or Cd$^{＋＋}$. 4. This enzyme was strongly inhibited by EDTA but was not inhibited by oxalic acid, citric acid, 2, 4-dinitrophenol, $\varepsilon$-aminocaproic acid, cysteine, or thiourea.

• The Korean Journal of Ecology
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• v.15 no.2
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• pp.137-145
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• 1992

When exposed to 1, 700 ml of 0.089, 0.445 or 0.890 mM/l cadmius solution, dock (rumex crispus L)plants from heavily polluted chungrangchon site absorbed 0.0404, 0.2244 or 0.4929 mM of cadmium per g dw during the first 4 hours, which were 5.0~30.8 times faster uptake rate than those of water hyacinth (eichhornia crassipes Solm. - laub). Zinc, with which cadmium generally occurs together, did not affect the uptake rate in the concentration range of 0.0306 ~0.0918 mM/l. rumex cripus from chungrangchon site and from less polluted shingalchon site, when exposed to 1, 700 ml of 0.089 mM/l solution for 3 days, removed 68.4% and 63.2%, repectively, of the cadmium initially present in the solution. And when exposed to cadmium solution of the same concentration for the second time after cadmium-free hydroponic culture for three days, these plants removed 76.1% and 66.8% of cadmium, respectively. These removal rates were not significantly different between collection sites or between exposures, but were about 2 times greater for the first exposure, and 2~5 times greater for the second exposure, than those of water hyacinth. these results incate that rumex cripus can absorb, and thus remove, large amount of cadmium ion in wastewater, and so can be used in wastewater treatment, e.g. soil trench method. since there was large difference among the plants in the ability to absorb cadmium, it should be possible to select for strain with greater ability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.12
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• pp.1829-1836
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• 2010

The district heating system distributes the heat generated from a cogeneration plant to wider locations. In this process, the district heating pipe (DHP) is subjected to internal and external loadings. The internal loadings are generally caused by the operating conditions such as water temperature and internal pressure. Frictional interactions between the pipes and the soil contribute to the external loadings. Thus, investigation of the mechanisms of failure of DHPs will help to guarantee both mechanical stability and heating efficiency. In this study, we investigate the local buckling of DHPs using limit state design (LSD). Two methods are considered: the use of the limit state for the width-thickness ratio and the use of the limit state for the strain. The results are used to confirm that the DHP is stable under local buckling. Finally, we suggest a minimum preheating temperature for avoiding local buckling.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.440-446
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• 1989

Penicillium sp. CB-20 was selected for its strong polygalacturonase activity among various strains of molds found in soil. It was found that the production of polygalacturonase reached to maximum when on the wheat bran medium containing pectin as carbon source, the strain was cultured for 60 hours at 3$0^{\circ}C$. The enzyme was purified to 29.21 food by ammonium sulfate treatment, Sephadex G-25, G-15, G-150 gel filtration, DEAE-cellulose and DEAE-Sephadex A-50 ion-exchange chromatography. Yield of the enzyme purification was 2.31 %. When the purified enzyme was applied to sodium dodecyl sulfate polyacrylamide gel electrophoresis, the molecular weight was estimated 21, 000. The amino acid composition indicated relatively high contents of gultamic acid, glycine and histidine.

• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1251-1258
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• 2010

During the nitrogen-fixing process, ammonia ($NH_3$) is incorporated into glutamate to yield glutamine and is generally not secreted. However, in this study, $NH_3$-excreting strains of nitrogen-fixing Paenibacillus were isolated from soil. The ammonium production by the Paenibacillus strains was assayed in different experiments (dry biomass, wet biomass, cell-free extract, and cell-free extract adsorbed on nano $TiO_2$ particles) inside an innovative bioreactor containing capsules of $N_2$ and $H_2$. In addition, the effects of different $N_2$ and $H_2$ treatments on the formation of $NH_3$ were assayed. The results showed that the dry biomass of the strains produced the most $NH_3$. The dry biomass of the Paenibacillus strain E produced the most $NH_3$ at 1.50, 0.34, and 0.27 ${\mu}M$ $NH_3$/mg biomass/h in the presence of $N_2$ + $H_2$, $N_2$, and $H_2$, respectively, indicating that a combined effluent of $N_2$ and $H_2$ was vital for $NH_3$ production. Notwithstanding, a cell-free extract (CFE) adsorbed on nano $TiO_2$ particles produced the most $NH_3$ and preserved the enzyme activities for a longer period of time, where the $NH_3$ production was 2.45 ${\mu}M$/mg CFE/h over 17 h. Therefore, the present study provides a new, simple, and inexpensive method of $NH_3$ production.

• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.40-44
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• 2018

An isolate capable of inhibiting the growth of gram-positive bacteria was obtained from the soil of Mushim stream, Cheongju. The isolate was identified as Pseudomonas otitidis PS by 16S rRNA gene sequence analysis. P. otitidis PS produced antibiotics as a secondary metabolite when cultured in 1% soybean meal with 0.5% glucose. The maximum yield was about 0.1%. The antibiotic substance of P. otitidis PS extracted using ethyl acetate displayed a minimum inhibitory concentration of $2{\mu}g/ml$ for Staphylococcus aureus KCTC 1261. The antibiotic substance produced an orange halo on chrome azurol S agar due to siderophore activity. Growth inhibition was decreased when the iron was depleted. Since the antibiotic activity was lost upon the addition of the reducing agent ascorbic acid or during anaerobic culture, it was considered that antibiotic of P. otitidis PS strain exerts its bactericidal effect by the generation of reactive oxygen species.

• Applied Biological Chemistry
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• v.36 no.6
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• pp.428-433
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• 1993

A strain that inhibited the growth of Pellicularia sasakii was isolated from the soil and identified as Pseudomonas aeruginosa 3120. A dark brownish antibiotic, MRL3120 isolated and purified from the culture broth of P. aeruginosa 3120 was soluble in ethylacetate, chloroform and methanol, and it was active against gram-positive and negative bacteria as well as fungi. The structure of MRL3120 was identified as a chelate compound consisting of two N-methyl-N-thioformyl-hydroxylamine and a copper ion by the analysis of UV, IR, and EI-MS spectra and other physico-chemical properties and supposed to have a structure of fluopsin C related compound. Addition of $CuSO_4$ into the fermentation medium containing soybean meal increased antifungal activity but no activity was found in the presence of EDTA (0.1%, v/v). However antibiotic MRL3120 was not produced in the fermentation medium containing soytone instead of soybean meal but it was rapidly produced by the addition of $CuSO_4$.