• Horticultural Science & Technology
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• v.34 no.1
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• pp.102-111
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• 2016

The goal of this study was to characterize the BrDSR (Drought Stress Resistance in B. rapa) gene and to identify the expression network of drought-inducible genes in Chinese cabbage under drought stress. Agrobacterium-mediated transformation was conducted using a B. rapa inbred line ('CT001') and the pSL100 vector containing the BrDSR full length CDS (438 bp open reading frame). Four transgenic plants were selected by PCR and the expression level of BrDSR was approximately 1.9-3.4-fold greater than that in the wild-type control under drought stress. Phenotypic characteristics showed that BrDSR over-expressing plants were resistant to drought stress and showed normal growth habit. To construct a co-expression network of drought-responsive genes, B. rapa 135K cDNA microarray data was analyzed to identify genes associated with BrDSR. BrDSR was directly linked to DARK INDUCIBLE 2 (DIN2, AT3G60140) and AUTOPHAGY 8H (ATG8H, AT3G06420) previously reported to be leaf senescence and autophagy-related genes in plants. Taken together, the results of this study indicated that BrDSR plays a significant role in enhancement of tolerance to drought conditions.

• The Plant Pathology Journal
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• v.22 no.3
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• pp.215-221
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• 2006

Gibberella zeae (anamorph: Fusarium graminearum) is an important pathogen of cereal crops. This fungus produces a broad range of secondary metabolites, including polyketides such as aurofusarin (a red pigment) and zearalenone (an estrogenic mycotoxin), which are important mycological characteristics of this species. A screen of G. zeae insertional mutants, generated using a restriction enzyme-mediated integration (REMI) procedure, led to the isolation of a mutant (Z43R606) that produced neither aurofusarin nor zearalenone yet showed normal female fertility and virulence on host plants. Outcrossing analysis confirmed that both the albino and zearalenone-deficient mutations are linked to the insertional vector in Z43R606. Molecular characterization of Z43R606 revealed a deletion of at least 220 kb of the genome at the vector insertion site, including the gene clusters required for the biosynthesis of aurofusarin and zearalenone, respectively. A re-creation of the insertional event of Z43R606 in the wild-type strain demonstrated that the 220-kb deletion is responsible for the phenotypic changes in Z43R606 and that a large region of genomic DNA can be efficiently deleted in G. zeae by double homologous recombination. The results showed that 52 putative genes located in the deleted genomic region are not essential for phenotypes other than the production of both aurofusarin and zearalenone. This is the first report of the molecular characterization of a large genomic deletion in G. zeae mediated by the REMI procedure.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.97.1-97
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• 2003

An antagonistic bacterium, KJ1R5,, to Phytophthora capsici was obtained from root interior of a healthy pepper plant. To identify the bacterial antagonist, 16S rDNA sequence analysis, Biolog system, fatty acid methyl-esters (FAMEs), and physiological and biochemical characterization were conducted. The determined 165 rDNA sequence of KJ1R5, showed higher similarities to those of a group consisting of several Chryseobacterium strains with 95.2, 95.2, and 95,1％ similarity to C. defluvii, Chryseobacterium sp. FR2, and C. scophthalmum, respectively, In addition, Halounella gailinarum, Bergeyella zoohelcum, and Riemerella anatipestifer are another group for KJ1R5, with 94.1, 89.7, and 87.2％ similarities, respectively When identification of the antagonistic bacterium, KJ1R5, was conducted using BIOLOG system, the strain KJ1R5, was identified as Flavobacterium tirrenicum (similarity； 0.75％). Fatty acid profiles of the strain KJ1R5, were composed mainly of iso-17：0 w9c and iso-15：0 and identified as Chryseobacterium balustinum (similarity 0.524％). KJ1R5, was Gram-negative, regular short rods ranging from 0.8 $\mu\textrm{m}$ to 1.0 $\mu\textrm{m}$ and had no flagella. Phenotypic characterization of the antagonistic bacterium indicated that KJ1R5, were included in the genus Chreseobacterium, which belongs to the family Flavobacteriaceae. The strain was distinguished from these six existing species. These results indicated that strain might be placed as a new species in the genus Chryseobacterium.

• Toxicological Research
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• v.17
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• pp.167-171
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• 2001

The introduction of genetically modified crops has raised concerns regarding safety issues over the insertion of foreign genes into plant genomes using recombinant DNA technology. Since 1991 in Japan, 29 foods and 6 food additives have been evaluated, based on the "Guideline for Safety Assessment", before these foods were marketed. The MHW, however, decided that safety assessment of such foods and food additives should be legally imposed. because soon such foods and food additives are expected to circulate globally and a new system for assessing safety of such foods and food additives at a pre-market stage is necessary, in order to avoid the distribution of any genetically modified foods that have had no safety assessment. The MHW published relevant announcements to amend existing regulations on 1 May 2000. "Standards for safety assessment of seed plant" is established based on a concept of substantial equivalence, and applicable to the products which are regarded as equivalent to the existing products used as foods and food additives. The characterization of the food products entails consideration of the molecular characterization. phenotypic and compositional characteristics, key nutrients and toxicants, and toxicity and allergenicity of the introduced proteins, and if there are indications of unintended effects of the modification, whether further safety testing (animal studies etc.) is needed should be considered. Safety and wholesomeness studies with whole foods should be care fully designed in order to avoid nutritional imbalances causing artifacts and uninterpretable results as was the case of Dr. Pusztaiis report. A case study of genetically modified soybeans (glyphosate-tolerant soybeans) on the immune system of rats and mice is shown. Chemical compositions were also compared with those of the non-GM soybeans. The studies failed to detect any differences in immuno-toxic activity.muno-toxic activity.

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.67-72
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• 2014

Minimal broth containing nicotine as a sole carbon source (MB/N) was used to isolate novel nicotine-degrading bacterial strains from tobacco plants and field soils. Comparative analysis of 16S rRNA gene sequence, phenotypic test and morphological tests showed that the position of these isolates were in the genus Arthrobacter of the family Micrococcaceae. The highest 16S rRNA gene sequence similarity of the isolate NU11 and NU15 to type strains in the genus Arthrobacter were Arthrobacter equi (98.2%) which was presumably a novel strain and Arthrobacter nicotinovorans (99.8%), respectively. Both strain NU11 and NU15 showed rod shaped, Gram-positive characteristics and catalase activity, but did not show oxidase activity. The novel strain NU11 was found to degrade efficiently nicotine in MB/N medium by the analysis of UV absorption spectra and could be used as an organism in bioremediation technique.

• Korean Journal of Veterinary Research
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• v.50 no.1
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• pp.29-35
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• 2010

Yersinia (Y.) ruckeri has been recognized as a serious bacterial pathogen to several kinds of fish, including rainbow trout. However, there are no reports about the characteristics and pathogenicity of Y. ruckeri isolated from farm-cultured eels. In this study, we isolated and characterized Y. ruckeri from the farm-cultured eel Anguilla japonica in Korea. We investigated the phenotypic and genotypic characteristics of Y. ruckeri and tested the virulence of Y. ruckeri isolates on experimentally infected eels. Examination of the flagellar morphology of Y. ruckeri by electron microscopy showed peritrichous flagella in its cell body. Biochemical reaction studies showed overall identical profiles between the isolates and the reference strain of Y. ruckeri in API 20E and API ZYM tests. We sequenced the 16S rRNA of the Y. ruckeri (1,505 bp) for the genotypic characterization (National Center for Biotechnology Information accession number EU401667). Comparison of the 16S rRNA sequences with previously reported Y. ruckeri strains revealed similar phylogenetic relationships. In the virulence assay of the Y. ruckeri on eels, the eels exhibited listlessness, but Y. ruckeri was reisolated from those of the gills and kidneys.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.792-798
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• 2006

The probiotic characteristics of a total of 137 lactic acid bacterial strains isolated from soybean paste were investigated. Among those tested, the D37 strain was selected as a probiotic bacteria due to its acid and bile tolerance, and its strong anti-cancer and antibacterial activities. The D37 strain showed highly stable viability at acidic pH for 2 hr, and was very stable in 10% bovine bile. The viability of human colon cancer HT-29 cells was inhibited more than 60% at a $200\;{\mu}/mL$ concentration of D37 cell-free culture supernatant, and the degree of inhibition was concentration-dependent. The D37 strain showed a wide range of antibacterial activities against food-borne pathogenic bacteria such as Escherichia coli O157, Listeria spp., Vibrio spp., Salmonella spp., and Staphylococcus aureus. According to phenotypic characteristics and the utilization of various sugars, the D37 strain was identified as Lactobacillus cellobiosus.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2001.10a
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• pp.14-17
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• 2001

Positional clonging (map-based cloning) of mutations or genetic variations has been served as an invaluable tool to understand in-vivo functions of genes and to identify molecular components underlying phenotypes of interest. Mice homozygous for the cerebellar deficient folia (cdf) mutation are ataxic, with cerebellar hypoplasia and abnormal lobulation of the cerebellum. In the cdf mutant cerebellum approximately 40% of Purkinje cells are ectopically located within the white matter and the inner granule cell layer (IGL). To identify the cdf gene, a high-resolution genetic map for the cdf-gene-encompassing region was constructed using 1997 F2 mice generated from C3H/HeSnJ-cdf/cdf and CAST/Ei intercross. The cdf gene showed complete linkage disequilibrium with three tightly linked markers D6Mit208, D6Mit359, and D6Mit225. A contig using YAC, BAC, and P1 clones was constructed for the cdf critical region to identify the gene. A deletion in the cdf critical region on chromosome 6 that removes approximately 150 kb of DNA selection. cdf mutant mice with the transgenic copy of the identified gene restored the brain abnormalities of the mutant mice. The positional cloning of cdf gene provides a good example showing the identification of a gene could lead to finding a new component of important molecular pathways.

• Journal of Sericultural and Entomological Science
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• v.37 no.1
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• pp.10-15
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• 1995

Genetic characterization of Sri Lankan silkworm bivoltine population has not been at-tempted so far, since its sporadic introduction of bivoltine strains into the island, starting from the 1950's. Genetic structure of Sri Lankan population of mulberry silkworm Bombyx mori was investigated through estimation of general (GCA) and specific combining ability(SCA) and heritability(${h^2}_B$), on the economic quantitative characters from leading 8 inbreds and their 28 F1's in a half diallel cross, in an attempt to utilize the estimates in determination of future breeding methods and to predict the breeding value over the phenotypic value. It was found that the breeding population of the bivoltine silkworm in Sri Lanka has still maintained considerable amounts of additive gene action as well as nonadditive. For some time in the future, both breeding strategies of "selection without inbreeding" and also "inbreeding followed by crossing" should therefore be effective in genetic improvement of economic characters investigated. In addition, superior combiners in general and in specific F1′s were identified for each of 6 economic characters, to be immediately utilized in selection and also in cross breeding programs in Sri Lanka.

• Korean Journal of Veterinary Research
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• v.52 no.4
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• pp.253-257
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• 2012

The purpose of this study was to investigate the prevalence of Brachyspira species and antimicrobial susceptibility of Brachyspira (B.) hyodysenteriae isolates in Korea. A total of fifty-five Brachyspira species were isolated; five (1.0%) beta-hemolytic Brachyspira species and 50 (10.4%) weak hemolytic Brachyspira species from 116 different diarrheic pig samples and 367 apparently normal pig samples. In farm level, beta hemolytic and weak hemolytic Brachyspira species were detected in 7.4% (5/68) and 19.1% (13/68) of tested pig farms, respectively. By phenotypic and genotypic characterization, all beta hemolytic Brachyspira isolates was classified as group I (B. hyodysenteriae), whereas weak hemolytic Brachyspira species isolates were group III (B. innocens or B. murdochii). B. hyodysenteriae isolates showed high level of minimum inhibition concentrations to macrolide antimicrobials. This study shows that the prevalence of pathogenic B. hyodysenteriae in pigs is low but antimicrobial resistance of the pathogens is high in Korea. This is the first report of the prevalence of Brachyspira group III and antimicrobial susceptibility of B. hyodysenteriae in pigs in Korea. Our results could provide basic data for the management and treatment guidelines of Brachyspira infection.