• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.423-430
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• 2006

A total of 367 isolates of Phytophthora infestans was collected from the leaf samples of late blight disease from five provinces in Korea over the three growing seasons of 2002-2004. Of the 367 isolates, 337 isolates were of the A1 mating type, and 30 isolates were of A2 mating type, showing that the majority was A1 mating type. Profiles of Gpi and Pep defined four allozyme genotypes among the total of 367 isolates. All four allozyme genotypes could be distinguished on the basis of Gpi profiles alone, whereas all isolates were homozygous at the Pep locus (100/100). The mitochondrial DNA haplotype of all isolates were the IIa haplotype. Amplification of the genomic DNAs extracted from eight isolates of each mating type by polymerase chain reaction with the selected primer (OPC-5 primer) produced a total of 20 DNA bands, of which 11 bands were polymorphic. According to the RAPD analysis using the OPC-5 primer, 106 isolates including two standard isolates were separated into 8 groups at the similarity level of 92.5%. The RAPD groups were not correlated with the allozyme genotypes and the isolated locations. All of the eight RAPD groups were identified in Gangwon-do, suggesting that Gangwon-do is the center of origin of the P. infestans in Korea. A 600-bp DNA band generated with the OPC-5 primer was specific to A1 mating type isolates, but not detected with A2 mating type, showing that the specific PCR primer can distinguish different mating types in P. infestans.

• Korean Journal of Plant Resources
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• v.17 no.3
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• pp.265-271
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• 2004

Genetic variation is the basis of crop improvement. Limited genetic diversity in a crop species may restrict the amount of genetic improvement that can be achieved through plant breeding. Soybean is one of the world's most important crops. A potential source of genetic variability for the cultivated soybean is the wild species G. soja Sieb. ＆amp; Zucc. Amplified fragment length polymorphism (AFLP) analysis is a PCR-based technique, which can detect a 10-fold greater nubmer of loci than other DNA marker analysis. Twenty cultivated soybeans and two-hundred wild soybeans were used to determine genetic vatiations by AFLPs and evaluate the usefulness of AFLPs as DNA markers. Six-hundred and ten fragments were detected with an average of 56 AFLP fragments produced per primer in a total of 11 AFLP primer pairs. The number of polymorphic loci detected per primer ranged from 7 to 20 and the polymorphism was greater in wild than in cultivated soybean. F$_2$ segregation analysis of four AFLP fragments in combination of Hwaeomputkong ${\times}$ PI 417479 indicated that they segregate as stable Mendelian loci with 3 : 1. This results strongly suggest that the AFLP analysis is a good technique for the detection of genetic polymorphism in a wide plant species.

• Mycobiology
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• v.29 no.1
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• pp.7-10
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• 2001

Based on the rDNA ITS sequences data, specific primer set for PCR detection of wood-decaying fungus Phellinus linteus was designed. The length of PCR products using designed primer set(SHF and SHR) was about 540 bp. Among 11 species, 17 isolates of Phellinus spp. including Phellinus linteus, P. pomaceus, P. spiculosus, P. baumi, P. pini, P. igniarius, P. gilvus, P. biscuspidatus, P. weirii, P. johnsonianus, P. robutus, and P. igniarius, seven isolates of Phellinus linteus showed about 540 bp-sized single band. This molecular technique could offer a useful tool for detecting and identifying Phellinus linteus.

• Korean journal of applied entomology
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• v.54 no.2
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• pp.91-97
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• 2015

The sweetpotato whitefly, Bemisia tabaci, is the major insect pest that transmitted over 100 plant viruses including tomato yellow leaf curl virus (TYLCV) of tomato plant as virus vector in the world. In this study, cDNA library of whitefly was constructed using Gateway system for selecting target gene in order to control of B. tabaci using virus-induced gene silencing (VIGS) vector with RNAi. First of all, when using oligo d(T) rimer, the calculated titer of cDNA library was confirmed with $1.4{\times}10^4$ clones and average insert sizes was confirmed with 1 kb. However, insert size was very big for construction of cDNA. Otherwise, when using attB-N25 random primer and sonication for 6 sec, the calculated titer of cDNA library was confirmed with $1.04{\times}10^5$ clones. But mostly insert band wasn't identified on the electrophoresis, because it seemed that insert size is too small (${\leq}100bp$), also the size of identified insert was somewhat big. Finally, when using oligo d(T) primer and sonication for 1 sec, cDNA insert of whitefly was appropriated for VIGS with 300-600 bp. However, cDNA sequence included a poly A and titer was very low to $5.2{\times}10^2$ clones. It was supposed that heat shock transformation was used instead of electro-transformation. It is considered that when constructing cDNA library for using VIGS vector, (1) random primer should be used for First strand cDNA synthesis in order to remove poly A and (2) sonication for 1 sec should be performed in order to get appropriated insert size and (3) electro-transformation should be performed in order to improve transformation efficiency.

• Horticultural Science & Technology
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• v.19 no.1
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• pp.29-33
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• 2001

This study was carried out to discriminate potato cultivars and breeding lines by specific molecular markers using random amplified polymorphic DNA (RAPD) analysis. The genotypes of potatoes used for analysis were eight cultivars and five breeding lines. Some of those show much phenotypic resemblances among them because 'Jopung', 'Daekwan70', 'Gawon', and 'Daekwan72' have immediate parental relationship with 'Superior', 'Irish Cobbler', 'Namsuh', and 'Atlantic', respectively. So, there are many difficulties to distinguish the varieties by the morphological characteristics. Three URP primers, URP2, URP4, and URP8 were selected for promising primers to discriminate potato genotypes or cultivars. The three URP primers were shown very high reproducibility because of the relatively high annealing temperature and long primer size. Although the results of similarity analyses did not always reflect the genetic relationship between potato varieties, the reproducible pattern of amplified DNA bands by URP primers showed possibility for molecular markers for discrimination of potato genotype or cultivar.

• Korean Journal of Microbiology
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• v.28 no.2
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• pp.91-97
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• 1990

Complementary DNA (cDNA) coding for human cytoplasmic superoxide dismutase (SOD1) (superoxide: superoxide oxidoreductase E.C.1.15.1.1) was isolated from human liver cDNA library of $\lambda$gt11 by in situ plaque hybridization. The insery cDNA gas the 5' untranslational region (UTR) and 3'UTR of SOD1 gene. Polymerase Chain Reaction (PCR) method was used fro subcloning of SOD1 structural gene. Using synthetic sense strand primer (24mer) containing a start codon and antisense strand primer (24mer), SOD1 structural gene was selectively amplified. Amplified DNA was directly cloned into the HincII site of pUC19 plasmid. Insery cDNA was subcloned into M13 mp19 and sequenced by dideowy chain termination method with Sequenase. The nucleotide sequence of insert cDNA had an open reading frame (ORF) coding for 153 amino acid residues. The structural gene of cytoplasmic SOD was placed under the control of bacteriophage $\lambda P_{L}$ regulatory sequences, generating a highly efficient expression plasmid. The production of human SOD1 in E. coli cells was about 7% of total cellular proteins and recombinant human SOD1 possessed its own enzymatic acitivity.

• 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 Food Science and Technology
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• v.41 no.3
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• pp.350-353
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• 2009

Peanut (Arachis hypogaea) often causes severe allergic reactions in sensitive people. Agglutinin is known to be one of the allergenic proteins in peanut. A polymerase chain reaction (PCR) method was developed to detect peanut ingredients in food using a primer pair corresponding to the agglutinin gene. This primer pair enabled PCR amplification of specific regions of agglutinin DNA from peanut, but not from 11 other nuts, beans, and cereals (pistachio, almond, sunflower seed, pine nut, walnut, soybean, black bean, kidney bean, azuki bean, rice, and black rice). The proposed PCR method successfully identified all of the 6 processed foods containing peanut whereas 13 other processed foods, which don't declare peanuts as an ingredient, were all negative. The detection limit of this method for purified peanut DNA was 100 pg/reaction. The sensitivity of this method was sufficient to detect peanut DNA in soybean DNA mixture which had been spiked with 0.1% peanut DNA.

• Horticultural Science & Technology
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• v.16 no.1
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• pp.21-24
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• 1998

RAPD markers were analyzed in order to detect the genetic variation and diversity of the fifty-two melon lines. SDS extraction method produced more and purer DNA than CTAB method. RAPD reaction conditions were optimized as follows ; 10ng template DNA, 270nM primer, $200{\mu}M$ each of dATP, dCTP, dGTP and dTTP, $0.3{\mu}unit$ dynazyme and 10x buffer brought to $15{\mu}l$ final volume with distilled water. The adequate annealing temperature was $39^{\circ}C$ and forty cycles of amplification produced the best RAPD band patterns. Among a total of 123 bands from 12 random primers, 25 polymorphic bands(20%) were selected as reliable markers. The average number of polymorphic bands per primer was 2.1 among the 52 lines. Intragroup genetic relationship based on the marker difference was closer than intergroup genetic relationship. The 52 lines could be grouped into two major group (Korean landraces and melon lines) and then melon group subdivided into two subgroups (net melon lines and no-net melon). This result corresponded to morphological grouping. Eight RAPD markers separated the Korean landraces and melon groups and four RAPD markers separated net melon and no-net melon groups.

• Biomedical Science Letters
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• v.6 no.1
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• pp.65-72
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• 2000

In order to improve the early diagnosis of Johne's disease in ruminants, duplex polymerase chain reaction system for the detection of the etiologic agent of M. paratuberculosis and for the differentiation of other mycobacterial animal pathogens, such as M. bovis and M. avium, was applied. Genomic DNAs were purified from peripheral blood monocytes or milk macrophages and were used as templates in the duplex PCR. Detection of Mycobacterium spp. in the specimen was carried out by PCR using primer set specific to the mycobacterial 16S rDNA. And then, mycobacterial DNA-positive specimens were further differentiated with duplex PCR system which was composed of primer sets specific to 16S rDNA of M. avium complex and Is900 gene of M. paratuberculosis. The results were re-confirmed by Southern blot hybridization with oligonucleotide specific to the internal sequence of IS900 PCR amplicons. The applicability of this duplex PCR system was evaluated with DNAs extracted from clinical specimens of peripheral blood monocytes and milk macrophages. In summary, the duplex PCR amplification system described in this experiment is promising molecular technique for the early diagnosis of Johne's disease in ruminants.