• Journal of the Korean Chemical Society
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• v.49 no.6
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• pp.537-545
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• 2005

• Journal of Life Science
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• v.15 no.3 s.70
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• pp.492-498
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• 2005

The mechanism of activation of phospholipase D2 (PLD2) remains undefined although mechanisms have been described for the activation of PLDI. By expression of mutated forms of haemaglutinnin-tagged PLD2 in a mast cell (RBL-2H3) line, we show that PLD2 is phosphorylated at tyrosines -11, -14, and -470 and that tyrosine-470 is critical for activation of PLD2 by antigen. Studies were performed with mutated-DNA constructs for haemaglutinnin-tagged PLD2 in which codons for tyrosine -11, -14, -165, and -470 were mutated to phenylalanine either individually or collectively. Transient expression of these constructs showed that mutation of tyrosine -11, -14, -470, or all tyrosines (all-mutated PLD2) suppressed antigen-induced tyrosine phosphorylation of PLD2 but only the tyrosine-470 mutant failed to be activated by antigen as assessed by in vitro assay of immunoprepitated PLD2 or by assay of PLD in intact cells. The critical role of tyrosine-470 was confirmed in studies with add-back mutants (phenylalanine back to tyrosine) of the all-mutated PLD. The findings provide the first description of a mechanism of activation of PLD2 in a physiological setting.

• Tuberculosis and Respiratory Diseases
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• v.50 no.1
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• pp.29-41
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• 2001

Background : The appearance of multiple-drug-resistant Mycobacterium tuberculosis strains has been seriously compromising successful control of tuberculosis. Rifampin-resistance, caused by mutations in the rpoB gene, can be indicative of multiple-drug-resistance, and its detection is of great importance. The present study aimed to develop an oligonucleotide chip for accurate and convenient screening of drug-resistance. Methods : In order to detect point mutations in the rpoB gene, an oligonucleotide chip was prepared by immobilizing specific probe DNA to a microscopic slide glass by a chemical reaction. The probe DNA that was selected from the 81 bp core region of the rpoB gene was designed to have mutation sites at the center. A total of 17 mutant probes related to rifampin-resistance including 8 rifabutin-sensitive mutant probes were used in this study. For accurate determination, wild type probes were prepared for each mutation position with an equal length, which enabled a direct comparison of the hybridization intensities between the mutant and wild type. Results : Mycobacterial genomic DNA from clinical samples was tested with the oligonucleotide chip and the results were compared with those of the drug-susceptibility test in addition to sequencing and INNO-LiPA Rif. TB kit test in some cases. Out of 15 samples, the oligonucleotide chip results of 13 samples showed good agreement with the rifabutin-sensitivity results. The two samples with conflicting result also showed a discrepancy between the other tests, suggesting such possibilities as existence of mixed strains and difference in drug-sensitivity. Further verification of these samples in addition to more case studies are required before the final evaluation of the oligonucleotide chip can be made. Conlcusion : An oligonucleotide chip was developed for the detection of rpoB gene mutations related to drugsusceptibility. The results to date show the potential for using the oligonucleotide chip for accurate and convenient screening of drug-resistance to provide useful information in antituberculosis drug therapy.

• Research in Plant Disease
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• v.25 no.1
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• pp.1-7
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• 2019

The rice blast fungus, Magnaporthe oryzae, is one of the most economically important crop diseases. In addition, rice-M. oryzae interaction is a classical gene-for-gene host-pathogen system. Race variation in pathogen groups was proposed as the main mechanism for rapid break-down of resistance in newly introduced rice cultivars. These new pathogen race variations may be caused by changes in an avirulence gene, such as (i) point mutations, (ii) insertion of transposons, and (iii) frame shifts. The avirulence gene AVR-Pita1 is representative avirulence gene in which all of these mutations are reported. In this review, we present a useful information for avirulence gene AVR-Pita1 and its homologous genes AVR-Pita2 and AVR-Pita3. We also review examples that cause mutations in these evolutionarily significant genes.

• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.290-297
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• 2009

This research aims to contribute the characterization of acetolactate synthase (Ec 4.1.3.18; ALS) and the resistance mechanism by sequence analysis of ALS gene of the sulfonylurea-resistant and -susceptible Monochoria vaginalis. The ALS gene was obtained from susceptible (S) and resistant (R) M. vaginalis to sulfonylurea herbicides (SUs). The 815 bp the fragment and the genomic DNA sequence coding for acetolactate synthase (ALS) of S and R biotypes of M. vaginalis were cloned and sequenced. Nineteen clones were divided greatly into 4 groups as result of sequencing. The first group was not difference to S type, the second group was amino acid of P197S which found point mutations causing substitution of serine for proline at amino acid 197, the third group was observed greatly other part of 6 places than group 1, and the fourth group appeared the intergrade of group 1 and 3. Therefore, it could be assumed what ALS gene of various types can be one plant. The peptide of the 13 amino acid Domain A region for ALS genes from R biotype of M. vaginalis differed from that of the S biotype by one base substitution at proline codon of Domain A. It could also be confirmed that point mutation of serine for proline at amino acid 197.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.247-254
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• 2010

Two-spotted spider mite, Tetranychus urticae was collected from the rose greenhouse in Chilgok, Gyeongbuk Province in December 2000. This population has been selected for ten years with bifenazate (over 450 times), and increased 855.9 fold in resistance as compared with susceptible strain (S). Cross resistance of bifenazate resistant (BR) strain to eight miticides was investigated. The BR strain exhibited high and low cross resistance to acequinocyl (614.0 fold) and to chlorfenapyr (9.1 fold), respectively. Against fenazaquin (0.3 fold) and fenpyroximate (0.1 fold), however, showed the strain negatively correlated cross resistance. Each strain collected in Choeng-ju (CJ), Kang-jin (KJ), and Chung-ju (CUJ) showed 5.5-, 964.5-, and 21.8-fold resistance to bifenazate, respectively. The detoxifying enzymes of the BR strain showed 1.6-fold activity in cytochrome $P_{450}$-dependent monooxygenase ($P_{450}$) as compared with susceptible one. By comparing the mitochondrial cytochrome b (cytb) sequence, G126S point mutation was detected in the BR and KJ strains.

• Korean Journal of Plant Taxonomy
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• v.35 no.4
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• pp.273-285
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• 2005

Genetic variation of notorious invasive plants, common ragweed (Ambrosia artemisiifolia L.) and giant ragweed (Ambrosia trifida L.) were examined using the internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA. A total of 18 different ITS types were detected from 156 individuals of common ragweed sampled mainly from the southern part of Korean peninsula whereas four types were identified from 46 individuals of giant ragweed. High sequence diversity observed from common ragweed in Korean populations was interpreted as multiple introduction. Genetic recombination was suggested as possible method for the production of some of the ITS types while point mutation was mainly responsible for the origin of the sequence diversity. This study provided some of basic genetic information needed for understanding of the evolutionary process in ragweed during invasion.

• Journal of Life Science
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• v.13 no.3
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• pp.291-297
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• 2003

A human endogenous retroviral family (HERV-W) has recently been described that is related to multiple sclerosis-associated retrovirus (MSRV) sequences that have been identified in particles recovered from monocyte cultures from patients with multiple sclerosis. Two pol fragments (HWP-FB10 and HWP-FBl2) of HERV-W family were identified and analysed by the PCR approach with cDNA library of human fetal brain. They showed 89 percent nucleotide sequence similarity with that of the HERV-W (accession no. AF009668). Deletion/insertion or point mutation in the coding region of the pol fragments from human fetal brain resulted in amino acid frameshift that induced a mutated protein. Phylogenetic analysis of the HERV-W family from GenBank database indicates that the HWP-FB10 is very closely related to the AC000064 derived from human chromosome 7q21-q22. Further studies on the genetic relationship with neighbouring genes and functional role of these new HERV-W pol sequences are indicated.

• Korean journal of applied entomology
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• v.63 no.1
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• pp.33-42
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• 2024

The green peach aphid, Myzus persicae is a representative agricultural insect pest that is polyphagous and causes serious damage to tobacco, potatoes, peppers, cabbage, and peaches. In this study, we analyzed the level of development of insecticide resistance to λ-cyhalothrin, imidacloprid, and flupyradifurone and the point mutations (R81T, L1014F, M918L) in 12 field populations of M. persicae. In addition, the expression level of CYP6CY3, a cytochrome P450 gene, was analyzed through qRT-PCR. As a result, λ-cyhalothrin showed high resistance ratio (RR) of > 200 in all 12 populations. Imidacloprid and flupyradifurone showed high RR of >200 in YS, UR, HY, and WJ populations. The R81T was detected in approximately 50%, L1014F in approximately 33.3%, and M918L in 100% of the 12 populations. Additionally, the expression level of subunit CYP6CY3 was highest in imidacloprid-resistant population (YS). These results suggest that M918L point mutation can be used as λ-cyhalothrin-resistance molecular diagnostic and R81T point mutation and the high expression of CYP6CY3 can be used as imidacloprid-resistance molecular diagnostic markers.

• Clinical and Experimental Pediatrics
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• v.45 no.2
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• pp.183-191
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• 2002

Purpose : X-linked agammaglobulinemia(XLA) is an immunodeficiency caused by abnormalities in Bruton's tyrosine kinase(Btk), and is characterized by a deficiency of peripheral blood B cells. We studied the cytoplasmic expression of Btk protein and analyzed the Btk gene in peripheral blood mononuclear cells from two siblings and one cousin with XLA, as well as additional family members. Methods : Btk protein expression was analyzed by flow cytometry. Isolation of the coding sequence of the Btk gene was performed by amplification using the reverse transcription-polymerase chain reaction(RT-PCR) technique. Sequence alterations were screened by the single-stranded conformation polymorphism(SSCP) method and characterized by standard sequencing protocols. Results : Cytoplasmic expression of Btk protein in monocytes was not detected in three patients with XLA. In addition, Btk protein analysis clearly showed cellular mosaicism in monocytes from four obligate carriers, findings further supported by SSCP. A single base pair mutation(T to C) in Btk-exon three, which encodes the PH domain, was identified in four XLA patients. A diagnostic sequencing analysis was established to detect heterozygotic pattern in 4 carrier females. Furthermore, we found significant clinical heterogeneity in individuals with the same gene mutation. Conclusion : The implicating genetic alteration provided valuable clues to the pathogenesis of XLA in Korea and the flow cytometric analysis was suggested as a useful tool for rapid detection of XLA patients and carriers. The present study has identified a genetic mutation in the Btk coding region and demonstrated heterogeneity in clinical manifestations among patients with the same mutation. A flow cytometric analysis was found to be informative in establishing a deficiency of Btk protein in both patients and carriers and is recommended as a frontline procedure in the molecular diagnosis and work-up of XLA.