• Journal of Microbiology and Biotechnology
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• 제20권10호
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• pp.1386-1392
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• 2010

A bacterial strain designated GR5$^T$, previously isolated from a freshwater culture pond in Taiwan while screening for bacteria for antimicrobial compounds, was characterized using a polyphasic taxonomic approach. Strain GR5$^T$ was found to be Gram-negative, aerobic, greenish-yellow colored, rod-shaped, and motile by means of a single polar flagellum. Growth occurred at $10-40^{\circ}C$ (optimum, $35^{\circ}C$), pH 7.0-8.0 (optimum pH 8.0), and with 0-2.0% NaCl (optimum, 0.5-1.0%). The major fatty acids were $C_{16:1}{\omega}7c$(36.3%), $C_{16:0}$(16.6%), $C_{12:0}$ 3-OH (12.5%), and $C_{18:1}{\omega}7c$(9.1%). The major respiratory quinone was Q-8, and the DNA G+C content of the genomic DNA was 51.9 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain GR5$^T$ belongs to the genus Rheinheimera, where its most closely related neighbors are Rheinheimera texasensis A62-14B$^T$ and Rheinheimera tangshanensis JA3-B52$^T$ with sequence similarities of 98.1% and 97.5%, respectively, and the sequence similarities to any other recognized species within Gammaproteobacteria are less than 96.5%. The mean level of DNA-DNA relatedness between strain GR5$^T$ and R. texasensis A62-14B$^T$, the strain most closely related to the isolate, was $26.5{\pm}7.6%$. Therefore, based on the phylogenetic and phenotypic data, strain GR5$^T$ should be classified as a novel species, for which the name Rheinheimera aquatica sp. nov. is proposed. The type strain is GR5$^T$ (=BCRC 80081$^T$=LMG 25379$^T$).

• International Journal of Railway
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• 제8권2호
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• pp.50-54
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• 2015

The primary function of the trackbed in a conventional railway track system is to decrease the stresses in the subgrade to be in an acceptable level. A properly designed trackbed layer performs this task adequately. Many design procedures have used assumed and/or are based on critical stiffness values of the layers obtained mostly in the field to calculate an appropriate thickness of the sublayers of the trackbed foundation. However, those stiffness values do not consider strain levels clearly and precisely in the layers. This study proposes a method of computation of stiffness that can handle with strain level in the layers of the trackbed foundation in order to provide properly selected design values of the stiffness of the layers. The shear modulus values are dependent on shear strain level so that the strain levels generated in the subgrade in the trackbed under wheel loading and below plate of Repeated Plate Bearing Test (RPBT) are investigated by finite element analysis program ABAQUS and PLAXIS programs. The strain levels generated in the subgrade from RPBT are compared to those values from RC (Resonant Column) test after some consideration of strain levels and stress consideration. For comparison of shear modulus G obtained from RC test and stiffness moduli $E_{v2}$ obtained from RPBT in the field, many numbers of mid-size RC tests in laboratory and RPBT in field were performed extensively. It was found in this study that there is a big difference in stiffness modulus when the converted $E_{v2}$ values were compared to those values of RC test. It is verified in this study that it is necessary to use precise and increased loading steps to construct nonlinear curves from RPBT in order to get correct $E_{v2}$ values in proper strain levels.

• Journal of Microbiology and Biotechnology
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• 제10권5호
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• pp.643-650
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• 2000

A new aniline-utilizing microorganism, strain HY1 obtained from an orchard soil, was characterized by using the BIOLOG system, an analysis of the total cellular fatty acids, and a 16S rDNA sequence. Strain HY1 was identified as a Burkholderia species, and was designated Burkholderia sp. HY1. GC and HPLC analyses revealed that Burkholderia sp. HY1 was able to degrade aniline to produce catechol, which was subsequently converted to cis,cis-muconic acid through an ortho-ring fission pathway under aerobic conditions. Strain HY1 exhibited a drastic reduction in the rate of aniline degradation when glucose was added to the aniline media. However, the addition of peptone or nitrate to the aniline media dramatically accelerated the rate of aniline degradation. A fatty acid analysis showed that strain HY1 was able to produce lipids 16:0 2OH, and 11 methyl 18:1 ${\omega}7c$ approximately 3.7-, 2.2-, and 6-fold more, respectively, when grown on aniline media than when grown on TSA. An analysison the alignment of a 1,435 bp fragment. A phylogenetic analysis of the 16S rDNA sequence based on a 1,420 bp multi-alignment sowed of the 16s rDNA sequence revealed that strain HY1 was very closely related to Burkholderia graminis with 95% similarity based that strain HY1 was placed among three major clonal types of $\beta$-Proteobacteria, including Burkholderia graminis, Burkholderia phenazinium, and Burkholderia glathei. The sequence GAT(C or G)${\b{G}}$, which is highly conserved in several locations in the 16S rDNA gene among the major clonal type strains of $\beta$-Proteobacteria, was frequently replaced with GAT(C or G)${\b{A}}$ in the 16S rDNA sequence from strain HY1.

• Journal of the Korean Geotechnical Society
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• 제18권4호
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• pp.147-157
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• 2002

In this paper, the testing cell and the related theory far the interpretation of constant rate of strain (CRS) consolidation test results in case of radial drainage were developed. The proposed method makes it possible to evaluate consolidation characteristics of clayey soil rapidly and accurately. To investigate the application of the developed testing device and theory, CRS consolidation tests and incremental loading(IL) tests in radial drainage condition with remolded and undisturbed samples were performed. Comparisons of consolidation parameters from consolidation curves including coefficient of consolidation values show the applicability and the reliability of the suggested method. The experimental data were compared with additional vertical drainage CRS tests and IL tests, and then were analyzed considering the effect of the drainage direction. In addition, the effect of excess pore water pressure generated during CRS consolidation test was investigated.

• Korean Journal of Soil Science and Fertilizer
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• 제25권4호
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• pp.394-400
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• 1992

In the isolated 280 Actinomycetes strains, 12 groups of Streptomyces were 87.2% and 3groups of Non-Streptomyces were 12.8%, respectively. Streptomyces with sporophore of the spiral chain form reached to 80% of all the Streptomyces isolates. Surface morphology of spores have been determined with the electron microscope ; two groups have a spiny surface, 10 groups have a smooth surface. Isolated Actinomyceles groups were indentified as Streptomycetes groups and Non-Streptomyces groups. Actinomycetes isolates were selected as the strains having predominant antibacterial activities against the microorganisms among the 15 groups which has antibacterial activities. Selected Actinomycetes isolates showed high antibiotic sensitivity of S-9 strain(8.46 r/ml), S-6 strain(6.23 r/ml), S-2 strain(7.24 r/ml) against Pseudomonas aeruginosa (ATCC 27857), Escherichia coli (ATCC 25922) and Staphylococcus aureus(ATCC 6538).

• Journal of Korean Society of Coastal and Ocean Engineers
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• 제17권1호
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• pp.9-15
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• 2005

Dredged soil from sea has much higher water content than liquid limit of clay and even if small loads apply, it will suffer a great settlement. Therefore it is very difficult to perform a consolidation test with general consolidation apparatus because of high water content. In this study Rowe cell apparatus consolidation tests have been performed with 5 slurry clays of a water content of 100%, 110%, 120%, 133%, and 150%. From the test results the consolidation characteristics such as compression index, secondary compression index, consolidation coefficient, and strain have been investigated with a variation of water content of dredged soil. The equations to get consolidation constants such as a compression index, a coefficient of consolidation, and strain have been proposed with the field water content.

• Korean Journal of Microbiology
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• 제42권1호
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• pp.47-53
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• 2006

A streptomycete strain was isolated from the soil samples from Korea. The chemotaxonomy and 16S rDNA sequencing confirmed that the strain belonged to the genus Streptomyces and we named it Streptomyces sp. AO-0511. Two antibiotics, herbimycin A and dihydroherbimycin A produced by this strain were tested for their physico-chemical and biological characteristics. Both compounds were stable under acidic pH. Dihydroherbimycin A was more heat-stable and polar compared with herbimycin A. Only weak antibacterial activities were detected against Bacillus subtilus ATCC 6633 and Micrococcus luteus ATCC 9341. However, herbimycin A and dihydroherbimycin A showed strong inhibitory activities on lung cancer cells (A549 cells) and leukemia cells (HL-60). The cytotoxicity was determined using L5178Y and P388 cell lines. The results showed that herbimycin A and dihydroherbimycin A had lower toxic effects on the cells compared with the standard compounds, comptothecin and cyclosporin A. Therefore, both compounds could be good candidates for the development of new anticancer drugs.

• Journal of the Korean Geotechnical Society
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• 제27권4호
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• pp.51-65
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• 2011

Shear banding, the localization of deformation into thin zones, has a quite practical relevance, as stability and deformation characteristics of earth structures are controlled by the soil behavior within the shear band. In this study, for understanding occurrence and developed pattern of shear band, plane strain compression tests were performed on three soils with different particle-size distribution under various conditions. Digital images were captured during the experiments; then, deformation of a specimen was evaluated by digital image analysis technique. The characteristics of a shear band were evaluated from the state shortly after post-peak occurrence to critical state. Additionally, the statistical procedure was developed to determine the reasonable thickness of a shear band.

• KSBB Journal
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• 제32권2호
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• pp.124-132
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• 2017

A methane-oxidizing bacterium was isolated from rice paddy field soil around Jeollanam-do province, Korea, and characterized. The isolate was gram-negative, orange pigmented and short rod ($1.1-1.2{\times}1.6-1.9{\mu}m$). It was catalase and urease-negative but oxidase-positive. The strain utilized methane and methanol as sole carbon and energy sources. It had an ability to grow with an optimum pH 7.0 and an optimum growth temperature $30^{\circ}C$. The strain was resistant to antibiotic polymyxin B but sensitive to streptomycin, kanamycin, ampicillin, chloramphenicol and rifampicin. The isolate required copper for their growth with concentration range of $2-25{\mu}M$, with an optimum of $10{\mu}M$. Under optimal culture condition, specific cell growth rate and generation time were found to be $0.046hr^{-1}$ and 15.13 hr, respectively. Phylogenetic analysis based on 16S rDNA sequences indicated that the strain formed a tight phylogenetic lineage with Methylomonas koyamae with a value of 99.4% gene sequence homology. So, we named the isolate as Methylomonas sp. SM4. 8.6 mM methanol was accumulated in the reaction mixture containing 70 mM sodium formate and 40 mM $MgCl_2$ (MDH inhibitor) under atmosphere of methane:air (40:60) mixture for 24 hr at $30^{\circ}C$.

• Korean Journal of Microbiology
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• 제37권4호
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• pp.239-244
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• 2001

We isolated a Myxobacteria strain from a soil sample obtained from Mt. Daedoon located in Choongnam, Korea. This strain, ARJ, secreted slime while swarmed on the surface of CT medium. It produced greenish yellow pigment in liquid or solid media, and the swarming edge showed green florescence under U. V. at 366 nm. It formed fruiting bodies when nutrient was exhausted, which is one of the most imkportant characteristics of Myxobacteria. The fruiting bodies did not have a stalk and consisted of naked myxospores when examined under the scanning electron microscope. These traits lead us to believe that this strain is very close to Myxococcus virescens. It showed antimicrobial activity, especially against Gram positive bacteria. Culture filtrate showed the activity but this was not due to protein. The culture filtrate also had proteolytic activity in which at least two enzymes are involved.