• Microbiology and Biotechnology Letters
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• v.20 no.2
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• pp.129-135
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• 1992

A chitinase gene of Serratia marcescens ATCC 27117 was cloned and expressed in Escherichiu di. A genomic library of S, marcescens was constructed with pUC 19 and screened using the swollen chitin agar plate for chitinolytic clones. A positive clone showing chitinclearance contains a recombinant pCHI 89, composed of 8.9 Kb chromosomal DNA fragment and pUC 19. Plasmid pCHI 89 produced 58 KD chitinase in E. coli, which was coincided with one of five extracellular chitinases produced by S. nzarccscens. Restriction endonuclease cleavage sites of the 8.9 Kb insert DNA fragment were mapped. E. coli JM109 harboring pCHI 89 inhibits the growth of a plant pathogenic fungus, Fusarium oxysporum.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.25 no.1
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• pp.1-8
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• 2020

Biogenic opal crash at about 6.7 Ma was identified at both IODP Site U1447 and NGHP Site 17 in the Andaman Sea. The different biogenic opal content and general variation pattern between two sites may be attributed to the different concentration of analytical reagent and sedimentation rate estimated by the different chronological approaches. Nevertheless, this study suggests that the biogenic opal crash in the Andaman Sea is closely related to the restriction of Indonesian Throughflow and to the decreasing strength of Indian summer monsoon during the late Miocene, both of which resulted in the reduction of nutrient supply.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.121-121
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• 1998

Artemisia annua, an indigenous plant in Korea, contains a clinically important potent antimalarial principle, artemisinin. Artemisinin is a cadinane-type sesquiterpene endoperoxide. Cadinane synthase catalyzes the first committed step in artemisinin biosynthesis by cyclizing farnesyldiphosphate. In hopes of finding a cadinane synthase gene involved in artemisinin biosynthesis, oligonucleotides were synthesized on. the basis of the consensus nucleotide sequences and Nco I restriction sites for convenience in cloning. Specifically, nucleotide sequences of two highly conserved regions were deduced from the genes of similar function of Hyoscyamus muticus, Nicotiana tabacum, Abies grandis, Lycopersicon esculentum, and Gossypium hirsutum to construct a set of primers for polymerase chain reation (PCR). A 184 bp fragment was found to be amplified by PCR, and subsequently cloned. The gene revealed 62.8% identity in nucleotide and 55.6% in amino acid sequence to correspondent gene of N. tabacum. The gene was different from another sesquiterpene cyclase gene of A. annua, germacranadiene synthase gene, recently reported by Mercke and Bordelius (1998).

• Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.49-56
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• 2012

Genetic variation in the Asian shore crab Hemigrapsus sanguineus was determined from partial mitochondrial DNA (mtDNA) sequences of the cytochrome b (Cytb) gene. Samples included 143 crabs from six localities along three coastlines in South Korea. A nucleotide sequence analysis revealed 38 variable sites in a 470-bp sequence, which defined 37 haplotypes. The haplotypes were not associated geographically and had a shallow genealogy. Pairwise $F_{ST}$ tests and a two-dimensional scaling analysis revealed no significant genetic differentiation among most of the populations. The low pairwise comparison values, but significant genetic differentiation of a northeastern population from all other populations, might have been influenced by a restriction in gene flow caused by hydrographic conditions such as ocean boundaries. The high haplotype diversity, low nucleotide diversity, and time since H. sanguineus expansion in Korean coastal waters indicate rapid population growth and a recent, sudden expansion in the Late Pleistocene.

• The Korean Journal of Zoology
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• v.31 no.3
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• pp.218-224
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• 1988

Restriction endonucleases were used to search for intraspecific variation at 32 cleavage sites in mitochondrial DNA(mtDNA) purified from fourteen strains of Drosophila melanogaster helonging to different localities of the world. mtDNA of D. melanogaster was displayed site variation(Hpall, Haelll and Seal endonucleases) and length variation(maxirnum 550bp). Six genotypes, Ml, M2, M3, M4, M6 and M7, could be distinguished based on ihe site types witti a low average of intraspecific substitution rate (1.88%),but M5 type of Ogasawara strain in Japan was not detected in this study. A possible explanation for the low divergence was that mtDNA variation of fourteen strains in D. melanogaster could not he accumulated sufficiently owing to recent divergence of few individuals, and that sequence divergence was prevented by frequent migration in spite of the geographical isolation.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.98-102
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• 1990

A strain of Erwinia spp. was selected from the soil for the production of bacteriocin to the root rot plant pathogen. Bacteriocin producing gene was not located on plasmid but on chromosome. Genomic library of Erwinia spp. were made by using pLAFR 3 as a vector system for cloning of the gene. It was been cloned and expressed in E. coli DH 5 . Bacteriocin producing colony was composed of pLAFR 3 vector and 3.0 kb EcoRI fragment of Erwinia spp. ehromosomal DNA. The inserted fragment (3.0 kb) was possessed a EcoRI and BarnHI restriction sites.

• Journal of Microbiology and Biotechnology
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• v.18 no.7
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• pp.1207-1215
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• 2008

To investigate the occurrence and species diversity of mycobacteria in waters, surface water samples were collected monthly from the Han River and tap water samples at the terminal sites of the distribution system. Mycobacteria in each water sample were isolated by decontamination using cetylpyridinium chloride (CPC) and cultivation on Middlebrook 7H10 agar, and then identified by polymerase chain reaction-restriction fragment length polymorphism analysis (PRA) and sequencing of the 65-kDa heat-shock protein gene (hsp65 gene). Mycobacteria were detected in 59% of the surface water samples and 26% of the tap water samples. Over half of the 158 isolates could not be identified by hsp65 PRA and gene sequencing, and several identification discrepancies were observed between the two methods. The most frequently isolated species was Mycobacterium gordonae in surface water and M. lentiflavum in tap water. M. avium complex (MAC), the most important pathogen among environmental mycobacteria, was detected in the surface water samples but not found in the tap water samples. The result demonstrated that water is an important environmental source of mycobacteria and the combined application of hsp65 PRA and sequencing was more reliable than hsp65 PRA alone to accurately identify mycobacteria present in water.

• Journal of environmental and Sanitary engineering
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• v.23 no.2
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• pp.1-18
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• 2008

The tetrachloroethylene (PCE) dehalogenase of Clostridium bifermentans DPH-1 (a halorespiring organism) was purified, cloned, and sequenced. This enzyme is a homodimer with a molecular mass of ca. 70 kDa and exhibits dehalogenation of dichloroethylene isomers along with PCE and trichloroethylene (TCE). Broad range of substrate specificity for chlorinated aliphatic compounds (PCE, TCE, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1,1-dichloroethylene, 1,2-dichloropropene, and 1,1,2-trichloroethane) for this enzyme was also observed. A mixture of propyl iodide and titanium citrate caused a light-reversible inhibition of enzymatic activity suggesting the involvement of a corrinoid cofactor. A partial sequence (81 bp) of the encoding gene for PCE dehalogenase was amplified and sequenced with degenerateprimers designed from the N-terminal sequence (27 amino acid residues). Southern analysis of C. bifermentans genomic DNA using the polymerase chain reaction product as a probe revealed restriction fragment bands. A 5.0 kb ClaI fragment, harboring the relevant gene (designated pceC) was cloned (pDEHAL5) and the complete nucleotide sequence of pceC was determined. The gene showed homology mainly with microbial membrane proteins and no homology with any known dehalogenase, suggesting a distinct PCE dehalogenase. So, C. bifermentans could play some important role in the initial breakdown of PCE and other chlorinated aliphatic compounds in sites contaminated with mixtures of halogenated substances.

• The Korean Journal of Zoology
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• v.35 no.3
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• pp.332-338
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• 1992

Samples of ho subspecies of striped field mice, Apodemus agrarius coreue & Apodemus ograrius cheiuensis, from four localities in Korea were used for the analyses of mitochondrial DNA fragment patterns resulted from the digestion with eight restriction enzvmes. A total of 31 fragments were recognized and 15 clones were revealed. The 15 clones were grouped into four major subgroups. One sample from Cheongiu was distinct, and formed one of the four major subgroups: the mean divergence wi6 other subgroups was 4.6 per cent, and extensive analyses using samples from various sites are necessary to clarify the taxonomic status of the subgroup. Samples from Cheju island constituted another subgroup, and they should be named as hpodemus cheiuensis. Samples from Wan island composed still another subgroup, and thew seemed to be another population of Apodemus chejuensis: further analvses are needed for the classification of Apodemus cheiuensis. In the last subgroup composed of six of seven samples from Cheongiu and four samples from Haenam, two samples from Cheonsiu and one sample from Haenam were identical in their mitochondrial genotypes, indicating that these striped field mice from Cheongiu and Haenam have close maternal relationship.

• Korean Journal of Plant Taxonomy
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• v.53 no.2
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• pp.148-156
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• 2023

Hibiscus hamabo (Malvaceae) is a deciduous shrub mainly found in northeast Asia, including China, Japan, and Korea. Due to its limited distribution on Jejudo Island and at several sites in Jeollanam-do in Korea, H. hamabo has been designated as an endangered species by the Ministry of the Environment and has been the subject of several restoration programs. In this study, we quantified genetic variations using double-digestion restriction-associated DNA sequencing technology in 96 individuals of H. hamabo from 13 distinct populations in Korea. We determined 3,352 genome-wide single nucleotide polymorphism loci after stringent filtering processes and analyzed the level of genetic variation within and among populations as well as the population differentiation and genetic ancestry with various assumptions pertaining to the population origin. Our results indicated weak differentiations among populations surveyed in this study but clearly suggested that most of the H. hamabo populations maintain a relatively high level of genetic diversity as evidence of frequent genetic exchanges among populations via outcrossing or sequential gene flows. For a more detailed analysis of the origin of Korean H. hamabo and its demographic history, it will be necessary to expand sampling in China and Japan.