• Journal of Microbiology and Biotechnology
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• 제19권7호
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• pp.647-650
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• 2009

Using 200 porcine colon tissues, the efficiencies of three isolation methods of Campylobacter from porcine intestines were compared: Method 1, direct streaking of colon mucosa; Method 2, direct inoculation of intestinal contents with a swab; Method 3, inoculation of pre-enriched medium. A total of 460 Campylobacter isolates were obtained from 178 samples (89%) by direct streaking of colon mucosa, 142 samples (71%) by direct streaking of a swab, and 94 samples (47%) by pre-enrichment of intestinal contents in Preston broth. Direct streaking of colon mucosa was superior to the other two isolation methods, in terms of rapidity and higher efficiency. When isolates were identified with various biochemical tests and PCRs specific to 16s rRNA, mapA, and ceuE, C. coli was the predominant species (87%) in porcine, whereas the rest of the isolates were identified as C. lanienae.

• Journal of Microbiology and Biotechnology
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• 제23권10호
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• pp.1428-1433
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• 2013

Jeotgal fermentation is dependent upon a diverse microbial community, although a detailed understanding of its microbial composition is limited to a relatively small number of jeotgal. Pyrosequencing-based bacterial community analysis was performed in fermented squid, ojingeo jeotgal. Leuconostoc was identified as the predominant bacterial genus, with Bacillus and Staphylococcus also accounting for a large proportion of the bacterial community. Phylogenetic analysis with 16S rRNA genes of Leuconostoc type species indicated that L. citreum- and L. holzapfelii-like strains could be the major Leuconostoc strains in jeotgal. High concentrations of NaCl were thought to be an important factor determining the makeup of the bacterial community in the fermented squid; however, a genomic survey with osmotic stress-related genes suggests the existence of more complex factors selecting the dominant bacterial species in fermented squid.

• Journal of Ginseng Research
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• 제17권2호
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• pp.148-152
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• 1993

One kind of microorganism was isolated and identified from Korean fresh, white and red ginseng, and the effect of a preservative, sodium benzoate on the microorganism and its thermal resistant propertues were studied. The results obtained were as follows. The predominant strain on ginseng and ginseng products was identified as Penicillium sp. The strain showed perithecium structure producing ascospores. The growth of the strain was slightly inhibited at 0.0571 concentration of sodium benzoate. The minimal inhibitory concentration (MIC) of sodium benzoate against the strain was 0.26%. The D value of the strain at 56, 59, $62^{\circ}C$ were 9.9, 5.0 and 4.5 min, respectively.

• Nuclear Engineering and Technology
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• 제30권1호
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• pp.17-25
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• 1998

Transport of carbon and boron impurity ions parallel to magnetic field lines in the tokamak SOL (scrape-off layer) is numerically investigated for a one-dimensional steady state. The spatial distributions of density and velocity of the impurity ions in a steady state are calculated by finite difference method for a single-fluid model. The calculated results show that among forces acting on SOL particles thermal force produced tv plasma temperature gradient is a principal force determining the feature of impurity distribution profiles in the tokamak edge. However, strong collisional friction forces appearing dominant in front of the diverter plate restrain impurity ion flows due to temperature gradients from moving toward the midplane. Consequently, the stagnation point develops in the impurity flow by these two forces near the diverter region, in which ion flows change their directions. Impurity ions turn out to be accumulated at the stagnation points, where peaked profiles of highly-ionized state ions are relatively predominant over those of low-ionized state ions.

• 한국임상수의학회지
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• 제35권5호
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• pp.175-177
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• 2018

The objective of this polymerase chain reaction (PCR)-based research was to determine the prevalence of vector-borne pathogens in stray cats in Yangju and Gwacheon cities, South Korea. Total 50 stray cats were sampled for this PCR-based survey; 33 samples and 17 samples were collected from Yangju and Gwacheon cities, respectively. Total positive presence rates were 6%, 6% and 24% for hemotropic mycoplasmas, Rickettsia spp. and Babesia spp., respectively in this study. Babesia spp. was the predominant pathogen present in the stray cats of both cities followed by hemotropic mycoplasmas and Rickettsia spp. It is recommended that a large-scale study of the prevalence of infectious agents among stray cats should be undertaken in all regions of South Korea.

• Animal Systematics, Evolution and Diversity
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• 제32권4호
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• pp.241-252
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• 2016

Out of the 12,100 slide-mounted specimens of Chironomidae collected throughout Korea from February 1977 to March 2016, 271 (2.2%) were from the genus Ablabesmyia (Diptera, Chironomidae, Tanypodinae). These 271 specimens were re-examined and eight species were identified, with three of these species shown to be new to science (A. hanea n. sp., A. microlongistyla n. sp., and A. paralongistyla n. sp.). It was discovered that A. monilis reported in 1981 and A. longistyla reported in 2009 had been misidentified, and corrected as A. prorasha in the present study. Among the eight species found from Korea, A. prorasha was predominant (37.8%), followed by A. longistyla (28.9%), and A. monilis (20.4%). A key of the eight species of Ablabesmyia found in Korea is provided.

• Journal of Plant Biology
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• 제8권4호
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• pp.1-6
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• 1965

Cytological observations were carried out to investigate the frequencies and geographical distribution of accessory chromosomes in rye in Korea. (1) All the 41 strains of rye investigated were found to have accessory chromosomes and the frequencies of accessories are ranged from 2 to 73.3%. (2) The frequency ranging from 30 to 40% was predominant and it included 13 different strains. (3) The edaphic factor seemed to play more marked role than the climatic factor in determining geographical distribution of accessories in rye in Korea. (4) Breakages of A-chromosomes into two fragments were observed in 11 plants. This phenomenon may throw some light on possible orgin of accessory chromosomes in rye.

• Journal of Microbiology
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• 제35권2호
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• pp.79-86
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• 1997

For the phylogenetic study of the genus Trichaptum, nuclear ribosomal DNA sequences from eight strains of four Trichaptium species were examined. Phylogenetic trees were constructed using molecular data on 18 rDNA and 5.8S rDNA and thei ITSs. Parsimony analyses of the Trichaptum species showed that T. biforme and T. laricinum made a monophyletic group respectively, suggesting that each species is phylogenetically independent. However, T. abietum represented a polyphyletic group and T. fusco-violaceum formed a polytomous group, suggesting that these species could be in the process of evolutionary differentiation. Examination of base substitutions of the 18S rRNA gene reveals that the C-T transition is most predominant and that there is a stronger transition bias between closely related organisms rather than between distantly related ones.

• 미생물학회지
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• 제17권3호
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• pp.137-151
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• 1979

Germinating conidia of Aspergillus nidulans diploid heterozygous for color and other genetic markers were used to direct and distinguish genetic events such as mutation, mitotic crossingover and nondisjunction in a single test after treatment with N-methyl-N'-nitro-N-nitrosoguanidine (NG), mitomycin C(MC), and chloral hydrate(CH). The following results were obtained : 1. NG reduced the survival of conidia and increased the frequencies of miototic segregants about sevenfoli over the control ; among the mitotic segregants the predominant genetic event was mitotic crossingover. NG also produced many abnormal colonies, which appeared to be of the types caused by induced semidominant lethals or chromosomal aberrations, and the aneuploid types found spontaneously. 2. After treatment with MC the survival of conidia was reduced but few abnormal colonies were produced. The frequencies of miotic segregants were increased about threefold over the control ; in the mitotic segeregants the induced genetic event was mitotic crossingover. 3. CH gave no apparent effect on the survival of conidia and the frequencies of mitotic segregants. However, CH generated abnormal colonies, very greatly, which turned out to be of the aneuploid types. This result suggests that CH interferes with the normal distribution of chromosomes in mitosis.

• The Journal of the Acoustical Society of Korea
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• 제21권3E호
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• pp.105-111
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• 2002

The parabolic equation technique provides an excellent model to describe the wave phenomena when there exists a predominant direction of propagation. The model handles the square root wave number operator in paraxial direction. Realization of the pseudo-differential square root operator is the essential part of the parabolic equation method for its numerical accuracy. The wide-angled approximation of the operator is made based on the Pade series expansion, where the branch line rotation scheme can be combined with the original Pade approximation to stabilize its computational performance for complex modes. The Galerkin integration has been employed to discretize the depth-dependent operator. The benchmark tests involving the half-infinite space, the range independent and dependent environment will validate the implemented numerical model.