• Journal of Plant Biotechnology
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• v.29 no.4
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• pp.217-222
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• 2002

Barley varieties collected from 1940 to 1951 allover the Korean peninsula by Dr. Takahashi Ryuhei were reintroduced from the Research Institute for Bioresouces in Okayama University, Japan, and the evaluation of morphological characteristics and RAPD analysis were performed. Totally, 493 varieties of Korean barley landraces were planted in the green house, from which seeds of 491 varieties were harvested and conserved in the seedbank of the Rural Development Administration. Majority of the naked barley varieties showed dense spikes with long awn, late heading, winter habits, and long plant height. However, variants having various phenotypes such as short awn, blue aleurone color, brachytic type and waxyness were also identified. Plant height, spike length, and cold-tolerance in the varieties were also highly variable among them. Homogeneity tests on the variation of growth habits, spike density, anthocyanin pigmentation on the seed coat, and hairiness on leaf sheath between naked and covered barley showed that the variations of naked barley were similar to those of covered barley. It maybe indicate that the most of naked barley landraces were mutated from the covered barley landraces. Korean landraces of naked barley were broadly divided into 4 groups by the dendrogram produced by morphological characteristics; however, the identities of the group were rather indistinct. Many varieties, belonged to the same group, were showed different band patterns in RAPD analysis using 5 different primer sets. These results indicate that the 112 varieties of naked barley landraces were different genotypes.

• Research in Plant Disease
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• v.15 no.3
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• pp.170-174
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• 2009

In this paper, we report a characterization of Prunus necrotic ringspot virus (PNRSV) isolate. The virus was identified from 'Yumyeong' peach showing mild mosaic on leaves in commercial orchard of 'Umsung', Chungbuk province in Korea. The virus isolate produced ringspot symptom on the inoculated cotyledons and systemic mosaic and malformation on the upper leaves of Cucumis sativus. Systemic mottles were appeared in Chenopodium quinoa. When the buds of the virus infected stem were grafted on the healthy young Prunus persica GF305 seedlings, line pattern with mosaic appeared within 3 months. Isometric virus-like particles were found in parenchyma cells and plasmodesmata of C. sativus leaves inoculated mechanically with the virus. The cDNA fragments of PNRSV coat protein (CP) region, approximately 675bp, were synthesized from genomic RNA extracted from virus-infected leaves by RT-PCR using specific primer pairs. Partial nucleotide sequences of the CP regions were determined and analyzed with the known PNRSV. The CP gene of PNRSVKorea isolates showed 93.9~94.7% similarity to the 4 known PNRSV isolates.

• Research in Plant Disease
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• v.26 no.4
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• pp.283-288
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• 2020

In September 2017, vein clearing and yellowing symptoms resembling those caused by viruses were observed on leaves of Malva verticillata in Chungnam, Korea. Nucleic acids were extracted from leaves of five symptomatic plants and tested by reverse transcription polymerase chain reaction using four virus specific primer pairs including malva vein clearing virus (MVCV). Amplicons of the expected size (600 bp) were obtained from total RNA of all samples using the MVCV-specific primers. To confirm the presence of MVCV in symptomatic plants, the DNA fragments from three samples were purified, and directly sequenced. BLAST analysis revealed that it shared the highest nucleotide identity (99%) with a MVCV isolate from tomato (Mexico). The virus isolates obtained from the third re-inoculated Chenopodium was designated as Cm1-5. Tissue from Cm1, Cm3, and Cm5 isolates was mechanically sap inoculated into 23 indicator plants. Cm3 isolate induced chlorotic local and mosaic symptoms in Althaea rosea. Phylogenetic analysis based on coat protein gene of 19 MVCV isolates from 6 different countries and plant species, did not correlated with either the geographical origin of the isolates, or pathogenicity. To our knowledge, this study first reports the natural occurrence of MVCV on M. verticillata in Korea and characterization of three Korean isolates of MVCV.

• Korean Journal of Dental Materials
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• v.44 no.1
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• pp.61-68
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• 2017

This study evaluated the effects of various cleaning methods on the shear bond strength of zirconia ceramics after saliva contamination. Eighty zirconia disk specimens were divided into 8 groups. All groups were treated with one coat of MDP primer. All specimens (except the negative control) were contaminated with human saliva on the zirconia surface. The positive control went through the bonding procedure immediately after contamination without any cleaning procedure. With the exception of control groups, the remaining six groups were rinsed with water and either applied with MDP recoating (WATER+MDP) or without MDP recoating (WATER). While some were cleaned with a Ivoclean with MDP recoating (IVOCLEAN+MDP) or not applied with MDP recoating(IVOCLEAN), others were cleaned with a 1% NaOCl solution with MDP recoating (NaOCl+MDP) or without MDP recoating (NaOCl). The shear bond strength of all specimens were measured after being stored in distilled water at $37^{\circ}C$ for 24 hours. The data was analyzed statistically by an analysis of ANOVA, Tukey's post hoc test and Student's t-test was used to compare the shear bond strength according to the re-coating of MDP after the cleaning procedure. The positive control group showed the lowest shear bond strength value, and the WATER group and NaOCl group showed no significant difference when compared to the positive control group. The IVOCLEAN group showed significantly higher shear bond strength when compared to Water group and NaOCl group but not with the group of negative control. After rinsing with water or the NaOCl solution, the comparison of the single coating of MDP and re-coating of MDP showed different shear bond strengths but there was no significant difference to the negative control. After rinsing with Ivoclean, there was no significant difference to the negative control regardless of the recoating of MDP. In conclusion, the shear bond strength was affected by the cleansing procedure and Ivoclean was found to be effective regardless of the re-coating of MDP. When water or the NaOCl solution is used to remove surface contaminants, the re-coating of MDP provides a positive effect on cementation.