• The Plant Pathology Journal
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• v.38 no.6
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• pp.572-582
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• 2022

Sheath blight disease caused by the necrotrophic, soilborne pathogen Rhizoctonia solani Kuhn, is the global threat to rice production. Lack of reliable stable resistance sources in rice germplasm pool for sheath blight has made resistance breeding a very difficult task. In the current study, 101 rice landraces were screened against R. solani under artificial epiphytotics and identified six moderately resistant landraces, Jigguvaratiga, Honasu, Jeer Sali, Jeeraga-2, BiliKagga, and Medini Sannabatta with relative lesion height (RLH) range of 21-30%. Landrace Jigguvaratiga with consistent and better level of resistance (21% RLH) than resistant check Tetep (RLH 28%) was used to develop mapping population. DNA markers associated with ShB resistance were identified in F₂ mapping population developed from Jigguvaratiga × BPT5204 (susceptible variety) using bulk segregant analysis. Among 56 parental polymorphic markers, RM5556, RM6208, and RM7 were polymorphic between the bulks. Single marker analysis indicated the significant association of ShB with RM5556 and RM6208 with phenotypic variance (R²) of 28.29 and 20.06%, respectively. Co-segregation analysis confirmed the strong association of RM5556 and RM6208 located on chromosome 8 for ShB trait. This is the first report on association of RM6208 marker for ShB resistance. In silico analysis revealed that RM6208 loci resides the stearoyl ACP desaturases protein, which is involved in defense mechanism against plant pathogens. RM5556 loci resides a protein, with unknown function. The putative candidate genes or quantitative trait locus harbouring at the marker interval of RM5556 and RM6208 can be further used to develop ShB resistant varieties using molecular breeding approaches.

• Biomolecules & Therapeutics
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• v.21 no.4
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• pp.313-322
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• 2013

Previous studies have demonstrated that repeated administration of the exogenous stress hormone corticosterone (CORT) induces dysregulation in the hypothalamic-pituitary-adrenal (HPA) axis and results in depression and anxiety. The current study sought to verify the impact of catechin (CTN) administration on chronic CORT-induced behavioral alterations using the forced swimming test (FST) and the elevated plus maze (EPM) test. Additionally, the effects of CTN on central noradrenergic systems were examined by observing changes in neuronal tyrosine hydroxylase (TH) immunoreactivity in rat brains. Male rats received 10, 20, or 40 mg/kg CTN (i.p.) 1 h prior to a daily injection of CORT for 21 consecutive days. The activation of the HPA axis in response to the repeated CORT injections was confirmed by measuring serum levels of CORT and the expression of corticotrophin-releasing factor (CRF) in the hypothalamus. Daily CTN administration significantly decreased immobility in the FST, increased open-arm exploration in the EPM test, and significantly blocked increases of TH expression in the locus coeruleus (LC). It also significantly enhanced the total number of line crossing in the open-field test (OFT), while individual differences in locomotor activities between experimental groups were not observed in the OFT. Taken together, these findings indicate that the administration of CTN prior to high-dose exogenous CORT significantly improves helpless behaviors, possibly by modulating the central noradrenergic system in rats. Therefore, CTN may be a useful agent for the treatment or alleviation of the complex symptoms associated with depression and anxiety disorders.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.3
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• pp.131-135
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• 2006

Coeruleo-vestibular pathway which connects locus coeruleus and vestibular nuclei is noradrenergic. This study was designed to elucidate the effects of phenylephrine on the spontaneous activity of acutely isolated medial vestibular nuclear neurons of rat by whole-cell patch-clamp technique. Sprague-Dawley rats, aged 14 to 16 days, were used. After enzymatic digestion, dissociated medial vestibular neurons were transferred to a recording chamber mounted on an inverted microscope, and spontaneous action potentials were recorded by standard patch-clamp techniques. In current-clamp mode, the frequency of spontaneous action potential of medial vestibular nuclear neurons was decreased by phenylephrine (n=15). Phenylephrine increased the amplitude of afterhyperpolarization without changes in the resting membrane potential and spike width. In voltage-clamp mode, the whole potassium currents of the medial vestibular nuclear neurons were increased by phenylephrine (n=12). These experimental results suggest that ${\alpha}-receptor$ mediates the inhibitory effects on the neuronal activity of the medial vestibular nuclear neuron.

• Korean Journal of Agricultural Science
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• v.43 no.2
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• pp.221-231
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• 2016

Microsatellites, which are sequences of repetitive short nucleotides, are abundant in the genome and have relatively many alleles at a locus. Hence, microsatellite markers are used in various research areas such as medicine, agriculture, and biology. Thanks to recent advanced techniques and databases associated with microsatellite marker development, foreign research relying on microsatellite markers is increasing in various study areas. In this study, by analyzing microsatellites-related articles published during 2000-2014 from eight Korean national journals representing zoology, botany, genetics, ecology and environmental science, breeding science, and forest science ('Animal Cells and Systems', 'Journal of Plant Biology', 'Genes and Genomics', 'Korean Society of Environment and Ecology', 'Korean Journal of Breeding Science', 'Journal of Agricultural Science, Chungnam National University', 'Journal of Korean Forest Society' and 'Forest Science and Technology'), we found that the number of articles and diversity of study subjects and objects have increased considerably. However, there are fewer applications of microsatellites in the national forest science area. During 2000-2014 in 'Journal of Korean Forest Society', the percentage of articles dealing with microsatellite markers was found to be the lowest with 4.2% among articles focusing on PCR-based markers including RAPD, AFLP, and ISSR. However, in 'Canadian Journal of Forest Research' and 'Forest Ecology and Management', microsatellite marker articles were represented at their highest with 69.2% and 76.2%, respectively. Given the advantages of microsatellite markers, the publication of research papers using microsatellites should be increased in Korean forest science journals to the level of studies published in prominent international journals.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.335-341
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• 2017

The complexity of the bacterial recombination system is a barrier for the construction of bacterial mutants for the further functional investigation of specific genes. Several protocols have been developed to inactivate genes from the genus Pseudomonas. Those protocols are complicated and time-consuming and mostly do not enable easy construction of multiple knock-ins/outs. The current study describes a single and double crossover-recombination system using an optimized vector-free allele-exchange protocol for gene disruption and gene replacement in a single species of the family Pseudomonadaceae. The protocol is based on self-ligation (circularization) for the DNA cassette which has been obtained by overlapping polymerase chain reaction (Fusion-PCR), and carries an antibiotic resistance cassette flanked by homologous internal regions of the target locus. To establish the reproducibility of the approach, three different chromosomal genes (ncRNA31, rpoN, rpoS) were knocked-out from the root-associative bacterium Pseudomonas stutzeri A1501. The results showed that the P. stutzeri A1501 mutants, which are free of any plasmid backbone, could be obtained via a single or double crossover recombination. In order to optimize this protocol, three key factors that were found to have great effect on the efficiency of the homologous recombination were further investigated. Moreover, the modified protocol does not require further cloning steps, and it enables the construction of multiple gene knock-in/out mutants sequentially. This work provides a simple and rapid mutagenesis strategy for genome editing in P. stutzeri, which may also be applicable for other gram-negative bacteria.

• Journal of English Language & Literature
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• v.58 no.1
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• pp.43-67
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• 2012

My essay aims at illustrating Whitman's homosexual vision of utopia with a close reading of his representative homosexual text, Calamus. His expansive self is based upon his intimate contact with the world and is almost always drawn to a wider vision of community in which different individuals share the locus of commonness and reach beyond their empirical boundaries. While foregrounding the contingent and the singular, Whitman forges bonds with other people through a series of ecstatic moments that carry us into the public sphere and common interests. Contrary to the current Whitman studies, his homosexual text doesn't repress contingency in order to celebrate the universal, but fully develops the commensurability among diverse historical agents. Whitman knows well the social taboos and inhibitions at the time of national crisis and expansion, but keeps imagining the world where homosexuality plays a central and significant role in founding a democratic solidarity and achieving a desirable social structure. His ideal of America is not a deferred wish for the future, but a concrete vision that can be achieved here and now, realized by the spontaneous bonding and instant attraction among free men. Instead of interpreting history or suggesting practical alternatives, he keeps questioning the dominant ideologies and the given orders of social control, and suggests a free and open relationship among men where no exterior power or mediating other intervenes. His utopian vision is radical as well as ideal, in that it rejects the interventions of the power structure and its institutions and courageously inscribes his homosexuality in the process of writing about and reading his contemporary America. As a predecessor of a homosexual utopian vision of America, Whitman has inspired many later poets, showing a possibility of infusing a homosexual identity into a radical imaging of the nation and its future.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.4
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• pp.285-289
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• 2000

This study suggests a rebar detection technique for simultaneous detection of size and cover of embedded reinforcement in concrete. The structure of the probe made in this study is somewhat different from commercial ones. This probe has three sensing coils. Rebar size and cover depth can be evaluated by detecting and analyzing the signal from them. Amplitude and phase variation of each coil in the probe was investigated using an impedance analyzer and the loci of transfer functions of the coils were analyzed. The locus of transfer function from the sensing coil positioned inside excitation coil was simple as well known, but the others from the coils outside excitation coil were not so. Actual experiment on rebar detection was performed with our probe and an eddy current test system for various rebar sizes and depths. The signal shape according to variation of cover depths showed the same tendency with the transfer function loci acquired by impedance analyzer. The different variation pattern of signal enabled to evaluate rebar size and cover depth simultaneously.

• Journal of Microbiology and Biotechnology
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• v.22 no.3
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• pp.422-430
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• 2012

Previous studies have demonstrated that repeated restraint stress in rodents produces increases in depression and anxiety-like behaviors and alters the expression of corticotrophin-releasing factor (CRF) in the hypothalamus. The current study focused on the impact of Bupleurum falcatum (BF) extract administration on repeated restraint stress-induced behavioral responses using the forced swimming test (FST) and elevated plus maze (EPM) test. Immunohistochemical examinations of tyrosine hydroxylase (TH) expression in rat brain were also conducted. Male rats received daily doses of 20, 50, or 100 mg/kg (i.p.) BF extract for 15 days, 30 min prior to restraint stress (4 h/day). Hypothalamic-pituitary-adrenal axis activation in response to repeated restraint stress was confirmed base on serum corticosterone levels and CRF expression in the hypothalamus. Animals that were pre-treated with BF extract displayed significantly reduced immobility in the FST and increased open-arm exploration in the EPM test in comparison with controls. BF also blocked the increase in TH expression in the locus coeruleus of treated rats that experienced restraint stress. Together, these results demonstrate that BF extract administration prior to restraint stress significantly reduces depression and anxiety-like behaviors, possibly through central adrenergic mechanisms, and they suggest a role for BF extract in the treatment of depression and anxiety disorders.

• Korean Journal of Biological Psychiatry
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• v.22 no.4
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• pp.173-178
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• 2015

Objectives Previous genome-wide association studies have indicated the association between ankyrin 3 (ANK3) and the vulnerability of schizophrenia. We investigated the association between single nucleotide polymorphisms (SNPs) covering the whole ANK3 locus and schizophrenia in the Korean population. Methods The study subjects were 582 patients with schizophrenia and 502 healthy controls. Thirty-eight tag SNPs on ANK3 and five additional SNPs showing significant association with schizophrenia in previous studies were genotyped. Results Three (rs10994181, rs16914791, rs1938526) of 43 SNPs showed a nominally significant association (p < 0.05) with at least one genotype model. But none of these associations remained significant after adjusting for multiple testing errors with Bonferroni's correction. Conclusions We could not identify a significant association between ANK3 and schizophrenia in the Korean population. However, three SNPs showing an association signal with nominal significance need to be investigated in future studies with higher statistical power and more specific phenotype crossing the current diagnostic categories.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.3
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• pp.331-339
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• 2008

The genetic structure and diversity of 15 Chinese indigenous chicken breeds was investigated using 29 microsatellite markers. The total number of birds examined was 542, on average 36 birds per breed. A total of 277 alleles (mean number 9.55 alleles per locus, ranging from 2 to 25) was observed. All populations showed high levels of heterozygosity with the lowest estimate of 0.440 for the Gushi chickens, and the highest one of 0.644 observed for Wannan Three-yellow chickens. The global heterozygote deficit across all populations (FIT) amounted to 0.180 (p<0.001). About 16% of the total genetic variability originated from differences between breeds, with all loci contributing significantly to this differentiation. An unrooted consensus tree was constructed using the Neighbour-Joining method and pair-wise distances based on marker estimated kinships. Two main groups were found. The heavy-body type populations grouped together in one cluster while the light-body type populations formed the second cluster. The STRUCTURE software was used to assess genetic clustering of these chicken breeds. Similar to the phylogenetic analysis, the heavy-body type and light-body type populations separated first. Clustering analysis provided an accurate representation of the current genetic relations among the breeds. Remarkably similar breed rankings were obtained with all methods.