• Korean Journal of Microbiology
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• v.38 no.2
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• pp.107-112
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• 2002

To isolate the bacteria lysing cyanobacteria, the sediment samples were collected from Dochang and Pal'tang Reservoir and Seokchon Lake. Each sample was smeared on the Anabaena cylindrica lawn and incubated in light chamber for 11 days. Bacteria having cyanobacteria-Iysing activity were isolated from the samples of Seokchon reservoir. Confirmation of cyanobacteria-Iysing activity was carried out to measure chlorophyll a and bacterial cell counting in mixed culture of Anabaena cylindrica and bacteria. Lysis was detected when extracellular meterials was added to the Anabaena cylindrica culture. The isolate was identified by analysis based on 16S rDNA sequence and morphological and physiological properties. The bacterial strain was taxonomically studied by the phylogenetic analysis based on 165 rDNA sequence. This strain was identified as a member of the genus Bacillus and designated as Bacillus sp. CHS1.

• Journal of KIISE:Software and Applications
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• v.32 no.12
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• pp.1217-1228
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• 2005

Recently, since DNA computing has been widely studied for various applications, DNA sequence design which is the most basic and important step for DNA computing has been highlighted. In previous works, DNA sequence design has been formulated as a multi-objective optimization task, and solved by elitist non-dominated sorting genetic algorithm (NSGA-II). However, NSGA-II needed lots of computational time. Therefore, we use an $\varepsilon$- multiobjective evolutionarv algorithm ($\varepsilon$-MOEA) to overcome the drawbacks of NSGA-II in this paper. To compare the performance of two algorithms in detail, we apply both algorithms to the DTLZ2 benchmark function. $\varepsilon$-MOEA outperformed NSGA-II in both convergence and diversity, $70\%$ and $73\%$ respectively. Especially, $\varepsilon$-MOEA finds optimal solutions using small computational time. Based on these results, we redesign the DNA sequences generated by the previous DNA sequence design tools and the DNA sequences for the 7-travelling salesman problem (TSP). The experimental results show that $\varepsilon$-MOEA outperforms the most cases. Especially, for 7-TSP, $\varepsilon$-MOEA achieves the comparative results two tines faster while finding $22\%$ improved diversity and $92\%$ improved convergence in final solutions using the same time.

• Journal of Korean Society of Forest Science
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• v.81 no.4
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• pp.320-324
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• 1992

It has been reported that there are two distinct phenotypes in Fraxinus mandshurica Rupr. growing in Korea. Recently developed polymerase chain reaction(PCR) was used to detect DNA sequence polymorphism in the species. Using a thermostable DNA polymerase and synthetic DNA primers, unknown DNA sequences from the species were randomly amplified. The two types of the species produced different DNA amplification pattern with three different primers tested. Although DNA polymorphism was detected among individuals within types, each type has its own distinct pattern. The two types could be easily differentiated by trier characteristic predominant bands.

• Mycobiology
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• v.28 no.1
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• pp.11-16
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• 2000

The nucleotide sequences of the internal transcribed spacer (ITS) regions of the ribosomal DNA including the 5.8S ribosomal RNA gene (rDNA) have been determined for 11 species in order to analyze their intrageneric relationships. The total length of these sequences ranged from 530 nucleotides for Trichoderma reesei KCTC 1286 to 553 nucleotide for Trichoderma koningii IAM 12534. Generally speaking, the length of ITS1 region was about 30 nucleotides longer than that of the ITS2 region. Also, the sequences of 5.8S rDNA were more conserved in length and variation than those of ITS regions. Although the variable ITS sequences were often ambiguously aligned, the conserved sites were also found. Thus, a neighbor-joining tree was constructed using the full sequence data of the ITS regions and the 5.8S rDNA. The Trichoderma genus used to be grouped on the basis of the morphological features and especially the shape of phialides needs to be reexamined. The phylogenetic tree displayed the presence of monophylogeny in the species of Trichoderma. Therefore, it was difficult to distinguish the intrageneric relationships in the Trichoderma genus.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.650-655
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• 1998

The chromosomal DNA fragment from Phaffia rhodozyma CBS 6938 which is able to autonomously replicate in the yeast Saccharomyces cerevisiae was cloned on an integrative URA3 plasmid. Its minimal fragment exhibiting autonomously replicating activiy in the S. cerevisiae gave a higher frequency transformation efficiency than that found for centromere-based plasmid, and enabled extrachromosoma1ly stable transmission of the plasmids in one copy per yeast cell under non-selective culture condition. The 836-bp DNA element lacked an ORF and did not contain any acceptable match to an ARS core consensus. Sequence analysis, however, displayed a cluster of three hairpin-Ioop-sequences with individual $\triangle {G_{25}}^{\circ}C$ free energy value of -10.0, -17.5, and -17.0 kcal. $mor^{-l}$as well as a 9-bp sequence with two base pair mismatches to the S. cerevisiae/E. coli gyrase-binding site. This 836-bp sequence also included one 7-bp sequence analogous to the core consensus of centromeric DNA element III (CDEIII) of S. cerevisiae, but CDEIII-like 7 bp sequence alone did not give a replicative function in this yeast.

• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.195-198
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• 2004

Molec-ular analysis was performed on the microflora found In the necrotic pulpal tissue collected from 5 infected root canals that were diagnosed as a periapical abscess. 16S rRNA coding gene (rDNA) library construction and sequencing were performed in order to identify the microflora, The 16S rDNA sequences from 278 clones were identified by a comparison with the database sequence in GenBank. Three phylum and 31 species, which were related to the oral microflora, were identified from the 3 samples (No. 87, 105, and 115). Dialister invisus (5.6％), Peptostreptococcus micron (18.3％), and Veillonella sp. (3.3％) were the organism present in all tee samples. Lac-tobacillusfementum (2.8％),Eubacterumsp./E. infirmum (6.7％), Shuttleworthiasatelles (3.9％), Psudorarnihacfer alactoiyticus (13.3％), Bulleidia moorei (2.8％), and Prevotella denticola (1.1％) were found in two samples. Two phylum and low species of environmental microflora were identified from 2 samples (No.95 and 101). The reason for this might be contamination of the samples with dental water. These results showed that molecular analysis could reveal more diverse microflora that are associated with endodontic infections than that revealed by conventional cultural methods. In addition, these results may of for the basic data to epidemiological studies related with endodontic infection.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.12
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• pp.1816-1821
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• 2003

Reliable PCR based identification of lactobacilli has been described utilizing the sequence of 16S-23S rRNA intergenic spacer region. Those sequence comparisons showed a high degree of difference in homology among the strains of L. rhamnosus, L. casei, L. acidophilus and L. helveticus whose 16S-23S rRNA intergenic small SR's sizes were 222 bp, 222 bp, 206 bp and 216 bp respectively. The sequence of 16S-23S rRNA intergenic spacer region of L. rhamnosus ATCC 53103 revealed the close relatedness to those of L. casei strains by the homology ranges from 95.4% to 97.2%. 16S-23S rRNA intergenic spacer region nucleotide sequence of L. acidophilus showed some distant relatedness with L. rhamnosus ATCC 53103 with the homology ranges from 40.3% to 41.8% and that with L. helveticus was shown to be 30% of homology, which exists at the most distant phylogenetic relatedness. The identification of species and strain of lactobacilli was possible on the basis of these results. The common sequences among the 17 strains were CTAAGGAA located in the initiating position of the DNA and some discrepancies were found between the same strains based on these results.

• Journal of fish pathology
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• v.32 no.2
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• pp.69-80
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• 2019

We performed MLSA (multilocus sequence analysis) and phenotypic characterization of Aliivibrio species isolated from walleye pollock (Gadus chalcogrammus) maintained in 3 different facilities of Gangwon Province, the east coast of Korea. Of 38 Aliivibrio species identified by 16S rDNA sequences, 12 strains were randomly selected and MLSA was conducted with 5 house-keeping genes (gapA, gyrB, pyrH, recA and rpoA) and 16S rDNA gene. Phylogenetic analysis and homology of the concatenated sequences (4,580 bp) with other Vibrionaceae genera revealed that 4 strains (GNGc16.1, YYGc16.1, YYGc16.2, GSGc18.1) were identified as Aliivibrio logei and one strain (GSGc16.1) as A. wodanis. One strain (GSGc17.1) was tentatively identified as A. logei, but needs further analysis because it did not belong to the same clade with A. logei type strain. 6 strains (GSGc17.2, GNGc16.2, GSGc16.2, GSGc17.3, GSGc18.2, GSGc17.4) need further investigation as potential novel species. Either phenotypic characterization or 16S rDNA sequence alone did not provide enough information for identification of Aliivibrio strains at the species level. A. logei and A. wodanis are generally known as non-pathogenic bacteria, but also known as opportunistic or secondary pathogens of cold water fishes. Cares should be taken to prevent potential outbreaks due to these bacteria, although there was no outbreaks during the sampling period.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.170-176
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• 2009

Culture-independent 16S rDNA-DGGE profiling and phylogenetic analysis were used to examine the predominant bacterial communities associated with the two sponges, Dictyonella sp. and Spirastrella abata from Jeju island. The culture-independent approach involved extraction of total bacterial DNA, PCR amplification of the 16S ribosomal DNA using primer pair 341f-GC and 518r, and separation of the amplicons on a denaturing gradient gel. Denaturing gradient gel electrophoresis banding patterns indicated 8 and 7 bands from the two sponge species, Dictyonella sp. and Spirastrella abata, respectively. There were not common major bands in two different sponges. Comparative sequence analysis of variable DGGE bands revealed from 93% to 98% similarity to the known published sequences. The dominant bacterial group of Dictyonella sp. belonged to uncultured Gammaproteobacteria, while, that of Spirastrella abata belonged to uncultured Alphaproeobacteria and Firmicutes. DGGE analysis indicated predominant communities of the sponge-associated bacteria differ in the two sponges from the same geographical location. This result revealed that bacterial community profiles of the sponges were host species-specific.

• Korean journal of applied entomology
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• v.42 no.1
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• pp.65-70
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• 2003

For the purpose of the protection of beneficial insects from pathogens and the development of control agent against pests, a strain of Metarhizium sp. was isolated from the infected Protaetia brevitarsis seulensis larvae in Korea. Under the scanning electron microscope, the isolate, Metarhizium sp. KMA-1, showed distinct formation of conidia on the palisade-like masse which were comprised of elongate chains and this shape is a typical feature of Metarhizium species. PCR techniques were used to identify the isolate and the primers used were designed on the basis of two kinds of rRNAs sequences, 28S rRNA and internal transcribed spacer(ITS). The specific PCR products from each primer set were amplified and the DNA sequences were determined for the similarity comparison. Sequence alignment of these fragments using GenBank database resulted in the highest homology similarity between the isolate Metarhizium sp. KMA-1 and M. anisopliae. From these results, the isolate Metarhizium sp. KMA-1 in this study was identified as M. anisopliae.