• The Plant Pathology Journal
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• v.25 no.1
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• pp.26-37
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• 2009

Tomato spotted wilt virus (TSWV) was identified from seven plants at two areas, Anyang and Dangjin, in Korea. The isolates of TSWV were seven as TSWV-KATm from tomato, TSWV-KAPo from potato, TSWV-KABal from balsam, TSWV-KACTm from cherry tomato and TSWV-KAIxe from Ixeris dentata at Anyang area, and TSWV-KDSe from sesame and TSWV-KDRP from red pepper at Dangjin area. Pathogenicity of seven TSWV isolates was various on the assay plants, and could not be grouped definitely. Three isolates of TSWV-KAIxe, TSWV-KACTm and TSWV-KABal had relatively narrower host ranges among the seven isolates. Percentage of nucleotide substitution in nucleotide sequences encoding nucleocapsid protein (NCP) was 1.2-1.7% among seven TSWV isolates and TSWV-KP. Korean TSWV isolates were divided into three groups by nucleotide homology or amino acid compositions. From the analysis of nucleotide sequences of Korean TSWV isolates compared with those of TSWV reported from other 5 countries including Japan, the Korean seven isolates of TSWV was grouped with German TSWV (D13926). No Korean TSWV isolates were grouped with those from The Netherlands, Brazil and USA.

• Korean Journal Plant Pathology
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• v.10 no.1
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• pp.25-28
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• 1994

One hundred fifty four our of 262 isolates of Fusarium oxysporum obtained from healthy plant tissues of various crops and their rhizosphere soil were found to be nonpathogenic to cucumber plants. The nonpathogenic isolates were frequently found from sesame plant tissues and rhizosphere soil, but less from healthy plant tissues of cucumber and water melon. When the 154 nonpathogenic isolates were preinoculated into cucumber seedlings, and then challenge-inoculated with Fusarium wilt pathogen, 21 isolates protected effectively cucumber plants from Fusarium wilt infections. A year later, 9 out of 21 isolates fully sustained their protective effect. Among 9 isolates showing good protective effects, 7 were isolates from cucumber plants. These 9 isolates except 1 isolate, were not pathogenic to water melon, chines melon, tomato and sesame.

• Korean Journal Plant Pathology
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• v.10 no.1
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• pp.29-33
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• 1994

One hundred fifty four out of 262 isolates of Fusarium oxysporum obtained from healthy plant tissues of various crops and their rhizosphere soil were found to be nonpathogenic to cucumber plants. The nonpathogenic isolates were frequently found from sesame plant tissues and rhizosphere soil, but less from healthy plant tissues of cucumber and water melon. When the 154 nonpathogenic isolates were preinoculated into cucumber seedlings, and then challenge-inoculated with Fusarium wilt pathogen, 21 isolates protected effectively cucumber plants from Fusarium wilt infections. A year later, 9 out of 21 isolates fully sustained their protective effect. Among 9 isolates showing good protective effects, 7 were isolates from cucumber plants. These 9 isolates, except 1 isolate, were not pathogenic to water melon, chinese melon, tomato and sesame.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.519-525
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• 1998

Intraspecific genetic diversity of Korean isolates of Phytophthora drechsleri was investigated based on PCR-RFLP of rDNA along with closely related species in the genus; P. cryptogea, P. melonis, P. erythroseptica, P. cinnamomi, P. cambivora and P. cactorum. Gene regions of nuclear small subunit and internal transcribed spacer (ITS) in rDNA were amplified with polymerase chain reaction and digested with 9 restriction enzymes. Phytophthora species was readily differentiated from each other based on the digestion patterns, however, P. cryptogea was not separable from some isolates of P. drechsleri. Twenty one isolates of P. drechsleri originated from 15 host plants were divided into three distinct groups designated as PdG1, PdG2 and PdG3, respectively. Four isolates in PdG1 were originated from green vegetables and tomato and nine isolates in PdG2 were mainly isolated from medicinal plants. The two groups showed 95.3% homology and four isolates of P. cyptogea came under the groups. However, Eight isolates in PdG3 collected from cucurbits were clearly differentiated from those of PdG1 and PdG2 by 66.5% homology, but completely matched with a Taiwan isolate of P. melonis. Results indicated that three distinct groups exist in Korean isolates of P. drechleri and each group has host preference. In addition, reclassification of the cucurbits isolates are reserved because of their distinct genetic characters from other intraspecific groups in P. drechsleri.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.985-992
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• 2007

The diversity of archaeal strains from six hypersaline environments in Turkey was analyzed by comparing their phenotypic characteristics and 16S rDNA sequences. Thirty-three isolates were characterized in terms of their phenotypic properties including morphological and biochemical characteristics, susceptibility to different antibiotics, and total lipid and plasmid contents, and finally compared by 16S rDNA gene sequences. The results showed that all isolates belong to the family Halobacteriaceae. Phylogenetic analyses using approximately 1,388 bp comparisions of 16S rDNA sequences demonstrated that all isolates clustered closely to species belonging to 9 genera, namely Halorubrum (8 isolates), Natrinema (5 isolates), Haloarcula (4 isolates), Natronococcus (4 isolates), Natrialba (4 isolates), Haloferax (3 isolates), Haloterrigena (3 isolates), Halalkalicoccus (1 isolate), and Halomicrobium (1 isolate). The results revealed a high diversity among the isolated halophilic strains and indicated that some of these strains constitute new taxa of extremely halophilic archaea.

• Korean Journal of Veterinary Service
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• v.39 no.3
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• pp.175-181
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• 2016

Staphylococcus pseudintermedius is an important opportunistic pathogen of dog and cats. Since 2006 there has been a significant emergence of methicillin-resistant S. pseudintermedius (MRSP) mainly due to clonal spread. The aim of this study was to investigated the prevalence of antibiotic resistance and presence of mecA and femA gene in 91 S. pseudintermedius isolates isolated from dogs and cats associated with various clinic infections. Methicillin resistance was confirmed by oxacillin disc diffusion method. MRSP isolate was detected 19 isolates (20.9%). MRSP and methicillin-resistant S. pseudintermedius (MSSP) isolates were highly resistant to penicillin, kanamycin, tetracycline, erythromycin, trimethoprim-sulfamethoxazole, clindamycin, ciprofloxacin, enrofloxacin and choloramphenicol (100~47.3% and 90.3~33.3%, respectively). About 90% of MRSP isolates were multi-drug resistance (resistance to at least five or more antimicrobials), and MSSP isolates was ca 74%. Among the 91 isolates, mecA gene was detected in 25 isolates (27.5%, 19 in MRSP isolates and 6 in MSSP isolates), but none carried the femA gene. Our results indicated MRSA isolates show a strong resistance to antimicrobials commonly used in veterinary medicine. A continuous surveillance and monitoring should be called for to prevent the contamination and spread of MRSP in dogs and cats.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.1
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• pp.35-43
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• 2011

Thirty five isolates of Trichoderma species collected from seven different locations of Bangladesh were studied for morphological characters and molecular variation. Mycelial diameters of the isolates varied from 8.28 cm to 9.00 cm. Based on colony colour, isolates were grouped into five such as dark green, green, light green, yellowish green and whitish green. Maximum isolates were green and light green. On the basis of growth habit and colony consistency, the isolates were categorized into three groups, in which most species had fast growth and were compact in appearance. PCR-based Random Amplified Polymorphic DNA (RAPD) technique employing 3 decamer primers produced 36 scorable bands of which all (100%) were polymorphic. The co-efficient of gene differentiation (Gst) was 1.0000 reflecting the existence of high level of genetic diversity among the isolates. The Unweighted Pair Group Method of Arithmetic Means (UPGMA) dendrogram constructed from Nei's (1972) genetic distance produced 2 main clusters (13 isolates in cluster 1 and 22 isolates in cluster 2). The result indicating their genetic diversity has opened new possibility of using the most efficient and more isolates of Trichoderma in the preparation of biopesticide and decomposition of municipality waste.

• Research in Plant Disease
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• v.29 no.2
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• pp.193-199
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• 2023

The apple stem grooving virus (ASGV) is one of the most harmful latent viruses infecting pear orchards worldwide. To examine the genetic diversity of ASGV in Korean pear orchards, the complete coat protein (CP) gene of five ASGV isolates collected from various regions were identified. The five Korean ASGV isolates showed 88-96% nucleotide identity with the 11 isolates worldwide occurring elsewhere in the world. Phylogenetic analysis of five isolates, as well as the previously sequenced isolates, indicated that the ASGV clusters had no correlation with the host or geographical regions of origin. Recombination analysis showed that one of the five Korean isolates is a recombinant, with a recombination site in the CP gene region (nt 532-708). This study is the first report of natural recombination within the CP gene of ASGV isolates from pears grown in Korea.

• The Plant Pathology Journal
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• v.25 no.2
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• pp.142-150
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• 2009

The complete genome sequences of RNA3 and RNA4 of the 13 different Rice stripe virus (RSV) isolates were determined and characterized in this study to address the possible causes of the recent re-emergence of RSV that affected many rice fields in Korea. The genome size of each RNA segment varied among isolates and significant differences were observed in the intergenic region. There was up to 4% average divergence in the RNA4 nucleotide sequence among 13 Korean isolates and only 1.4% in the RNA3. Phylogenetic relationships among different Korean isolates revealed that there were at least 2 types of RNA3 and 4 distinct types of RNA4 genomes present in Korea. However, Korean isolates with one type of RNA3 predominate over the other while the occurrences of the RSV Korean isolates with the 4 types of RNA4 genome were not correlated to specific geographical areas. Results further indicate that RNA4 had diverged more than RNA3 and these differences in accumulation of mutations in the individual RNA segments indicate that genetic reassortment were likely to contribute to the genetic divergence in the 13 Korean isolates. All of the Korean-RNA3 sequences except for one isolate grouped with Chinese isolates (JY and Z). In contrast, the RNA 4 sequences segregated together with either Chinese (JY and Z) and Japanese (M and T) isolates but genetic relationships of Korean isolates- RNAs 3 and 4 segments to Chinese-Y isolate were low. Altogether, these results suggest that the occurrence of mixtures of RNAs 3 and 4 genotypes in the natural population of RSV may have contributed to the sudden outbreak in Korea.

• The Journal of Korean Society of Virology
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• v.28 no.4
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• pp.347-358
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• 1998

To analyze the correlation between biological phenotypes of HIV-1 isolates and disease progression, we selected 9 long-term non-progressors (LTNP) and 12 rapid progressors (RP) from HIV-1 infected Korean. We isolated HIV-1 isolates by culture of PBMC of LTNP and RP with normal PBMC and measured HIV-1 p24 antigen production. The HIV-1 isolation rate from LTNP was 55.6% (5/9). And 4 HIV-1 LTNP isolates were non-syncytium inducing (NSI) phenotype and showed slow/low replication. The HIV-1 isolation rate from RP was 91.7% (11/12) which was higher than that from LTNP. Besides 3 RP HIV-1 isolates which showed syncytium inducing (SI) phenotype, 8 RP HIV-1 isolates showed NSI phenotype in normal PBMC and MT-2 cell line. All RP HIV-1 isolates replicated more rapidly than LTNP HIV-1 isolates. Comparing the replication kinetics and syncytium forming capacity of HIV-1 isolates from LTNP and RP, we suggest that the difference of biological phenotype of HIV-1 isolates could be related with disease progression of HIV-1 infected persons.