• Journal of Microbiology
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• v.34 no.3
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• pp.229-235
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• 1996

Microgram quantities of DNA per gram soil were recovered with SDS- based and freeze-and thaw procedures. The average DNA fragment size was > 23 Kb. This method generated minimal shearing of extracted DNA. However, the DNA extracts still contained considerable amounts of humic impurities sufficient to inhibit PCR. Several approaches were used to reduce the interferences with the PCR (use of CTAF in extraction step, Elutip-d column purification, addition of BSA to PCR buffer) to accomplish PCR with DNA extract as a template. Most of the DNA extracts were not digested completely by restriction endonuclease, and CTAB-TREATED ane Elutip-d column purified DNA extracts were partially digested. Regarding as restriction enzyme digestion, all PCRs failed to amplify 16S rRNA gene fragments in the DNA extracts. In the case of DNA extracts only where BSA was added to PCR buffer, PCR was successfully conducted whether the DNA extracts were treated with CTAB or purified with columns. However, these two treatments were indispensable for humic impurity-rich DNA extracts to generate the PCR-compatible DNA samples. Direct extraction of DNA, coupled with these procedures to remove and relieve interferences by humic impurities and followed by the PCR, can be rapid and simple method for molecular microbiological study on soil microorganisms.

• Journal of Life Science
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• v.21 no.9
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• pp.1329-1335
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• 2011

Korean native goats, which are characterized by black coat color, have existed on the Korean peninsula for a long time. Until now, there has been no comprehensive investigation concerning their genetic diversity, phylogenetic analysis or origin. In this study, we investigated the genetic diversity and verified phylogenetic status of the Korean native goat using the 453-bp fragment of the hypervariable fragment I (HVI) of mitochondrial DNA (mtDNA) D-loop region from 60 individuals among 5 populations. The Korean native goat showed less haplotype diversity when compared with goats from other countries. In addition, 6 haplotypes that had not been previously reported were verified in this study. In phylogenetic analyses with other country's goats, 10 haplotypes from Korean native goats were classified into mtDNA lineage A. Moreover, in a phylogenetic tree for goats which contained mtDNA lineage A, 8 of 10 haplotypes could be included in a subgroup with goats from Vietnam and an area of China. However, none of the remaining haplotypes belonged to a major group of Korean native goats and were located on different independent positions. These results suggest that almost Korean native goats aligned more closely to China and Vietnam breeds in mtDNA lineage A and there was no gene flow from other mtDNA lineages. Our results will contribute to conservation strategies and genetic breeding of Korean native goats.

• Mycobiology
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• v.31 no.2
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• pp.74-80
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• 2003

Isolates of Trichoderma spp. collected from Pleurotus ostreatus and P. eryngii beds, which included loosened substrate compactness and development of green colour, were grouped into three species. The occurrence of different species of Trichoderma was as T. cf. virens(70.8%), T. longibrachiatum(16.7%) and T. harzianum(12.5%). The conidia of Trichoderma spp. were ellipsoidal, obovoid and phialides were bowling pins, lageniform and the length of phialides was $3.5{\sim}10.0{\times}1.3{\sim}3.3{\mu}m$. Phialides of T. cf. virens and T. harzianum were tending clustered, but it was solitary disposition in T. longibrachiatum. T. cf. virens was characterized by predominantly effuse conidiation, sparingly branched, and fertile to the apex and it was penicillate type. RAPD analysis could detect variability amongst three different species of Trichoderma using two newly designed URP-primers. However, intra-specific variation could not be detected in all the isolates except for rDNA sequence data classified Trichoderma isolates into three distinct groups representing three species. The profiles of rDNA sequences of isolates representing a species showed high similarity in T. cf. virens and T. harzianum. However, there was a variation in rDNA sequences of isolates representing T. longibrachiatum. The results of present study reveals that molecular techniques of RAPD and rDNA sequencing can greatly aid in classification based on morphology and precise identification of fast evolving species of Trichoderma.

• Journal of Nutrition and Health
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• v.27 no.7
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• pp.740-751
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• 1994

Sister chromatid exchanges(SCE) in peripheral lymphocytes is recently used as a biomarker for increased cytogenetic damage in smokers. The purpose of the investigation was to determine if there were any relationships between dietary factors and their DNA damage as measured by SCE test in a group of 62 male cigarette smokers and 36 non-smokers. As expected, smokers as compared with non-smokers had high SCE levels (10.59$\pm$0.21 versus 9.23$\pm$0.17 SCE/lymphocytes ; p<0.05). No significant relationships were observed between SCEs and age in smokers and non-smokers. In smokers, SCEs were negatively correlated with egg frequency score(r=-0.336) and total food frequency scores(r=-0.283). In non-smokers, SCEs were positively correlated with white vegetable frequency score(r=0.333) and instant food frequency score(r=0.382). There was a positive association between SCEs and the history of coffee intake of smokers(r=0.318). SCE frequency was not influenced by any other dietary factors considered ; dietary diversity and quality scores, alcohol consumption, use of processed foods and intake of burned food. No significant relationships were found between SCEs and serum cholesterol or other hematological parameters of the subjects. These results indicate that increased egg frequency score, total food frequency score which reflects dietary quality, and decreased coffee intake may reduce cancer risk by preventing smoking-induced DNA damage as reflected by sister chromatid exchanges in human lymphocytes.

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.599-606
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• 2004

Gram-positive antagonistic bacilli were isolated from agricultural soils for possible use in biocontrol of plant pathogenic fungi, Fusarium oxysporum, Rhizoctonia solani, and/or Pythium ultimum. Among the 65 antagonistic Gram-positive soil isolates, 22 strains were identified as Bacillus species by 16S rDNA sequence analyses. Four strains, including DF14, especially exhibited multiple antagonistic properties against the three damping-off fungi. Genotypic properties of the Bacillus isolates were characterized by rapid molecular fingerprinting methods using repetitive extragenic palindromic-PCR (REP-PCR), ribosomal intergenic spacer-length polymorphisms (RIS-LP), 16S rDNA PCR-restriction fragment length polymorphisms (PCR-RFLP), and strain-specific PCR assays. The results indicated that the REP-PCR method was more valuable than the RIS-LP and 16S rDNA PCR-RFLP analyses as a rapid and reliable approach for bacilli typing and identification. The use of strain-specific primers designed based on 16S rDNA sequence comparisons enabled it to be possible to selectively detect a strain, DF14, which is being used as a biocontrol agent against damping-off fungi.

• International Journal of Oral Biology
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• v.38 no.1
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• pp.29-36
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• 2013

Mitis group streptococci (MGS) were classified based on the nucleotide sequences 16S rRNA gene (16S rDNA) and comprised 13 Streptococcus species. However, 16S rDNA homogeneity among MGS was too high to discriminate between clinical strains at the species level, notably between Streptococcus mitis, Streptococcus oralis, Streptococcus pneumoniae, and Streptococcus pseudopneumoniae. The purpose of this study was to discriminate between 37 strains of MGS isolated from Korean oral cavities using phylogenetic analysis of the DNA-dependant RNA polymerase beta-subunit gene (rpoB). 16S rDNA and rpoB from clinical strains of MGS were sequenced using the dideoxy chain termination method and analyzed using MEGA version 5 software. The resulting phylogenetic data showed that the rpoB sequences could delineate clinical strains of MGS at the species level. Phylogenetic analysis of rpoB is therefore a useful approach for identifying MGS at the species level.

• The Plant Pathology Journal
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• v.21 no.3
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• pp.229-236
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• 2005

Molecular profIles of PCR-RFLP and sequence analysis of internal transcribed spacer (ITS) regions of rDNA were compared between morphologically distinguishable species of Trichoderma isolated from substrates of oyster mushroom in Korea, T. atroviride, T. citrinoviride, T. harzianum, T. longibrachiatum, T. virens, and two unidentified species, Trichoderma sp. 1 and 2. PCR­RFLP analysis divided the Trichoderma spp. into six RFLP groups, A, B, C, D, E, and F. The RFLP groups were generally agreed with described morphological species, except that the RFLP group A containing the two unidentified species. A neighbor-joining tree based on ITS sequences well supported RFLP groups observed by RFLP analysis of ITS regions of rDNA. Additionally, the two unidentified species, Trichoderma sp. 1 and 2, which could not be distinguished by PCR­RFLP analysis, were separated in sequence analysis of ITS regions of rDNA.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.302-306
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• 2004

A total of forty strains of pigment-producing halophilic bacteria were isolated from the solar saltern and coastal seawater in Korea. The diversity of those bacteria were determined on the basis of PCR-RFLP and 16S rDNA sequences. The isolated strains were clssified into nine genera: Pseudoalteromonas, Photobacterium, Vibrio, Halobacillus, Bacillus, Paracoccus, Salinicoccus, Tenacilbaculum, and Flavobacterium. While more than $80\%$ of the pigment-producing halophilic bacteria isolated from the coastal seawater were classified as gram-negative Pseudolateromonas, most of the strains isolated from the solar saltern were classified into gram-positive Halo­bacillus. The other strain was KK7, which may be identified as novel species belonging to the genus, Salini­coccus.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.633-638
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• 2002

Nuclear 18S ribosomal RNA gene (185 rDNA) from the aquaculturable seaweed Porphya yezoensis (Bangiales, Rhodophyta) was amplified using the polymerase chain reaction and its sequence was analysed. Complete 185 rDNA has an 1823 bp exon and a 514 bp intron. The G+ C contents of exon and intron were $48\%$ and $51.4\%$, respectively. The exon sequence showed $99.5\%$ homology to the GenBank accession number AB013177 of the Japanese p. yezoensis. The intron region that was inserted upstream between 568 and 1083 showed $93.4\%$ homology to the AB013177.

• Journal of Microbiology
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• v.41 no.4
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• pp.327-334
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• 2003

This study employed two PCR-based 16S rDNA approaches, amplified rDNA restriction analysis (ARDRA) and denaturing gradient gel electrophoresis (DGGE), to characterize the bacterial community structure in groundwater. Samples were collected from groundwater for the use by private residences, as well as for industrial and agricultural purposes, in Ansan City. Each PCR product was obtained by PCR with eubacteria 16S rDNA and variable V3 region specific primer sets. After amplification, the 16S rDNA PCR products were digested with 4-base site specific restriction endonucleases, and the restriction pattern analyzed. The genetic diversity and similarity of the groundwater bacterial community was analyzed by eubacteria universal primer sets for the amplification of variable V3 regions of the bacterial 16S rDNA. The result of the bacterial community analysis, by ARDRA and DGGE, revealed the same pattern. The highest diversity was found in groundwater from site G1, which was used in residences. In the DGGE profile, a high intensity band was sequenced, and revealed to be Pseudomonas sp. strain P51.