• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.833-847
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• 2016

Drought stress is a major agricultural limitation to crop productivity worldwide, especially by which leafy vegetables, plant leaves eaten as vegetable, could be more lethal. The study was carried out to know the effect of drought tolerance plant growth promoting bacteria (PGPB) on water stress of kale seedlings. A total of 146 morphologically distinct bacterial colonies were isolated from bulk soil and rhizosphere soil of leafy vegetables and screened for plant growth promoting microbioassay in greenhouse. Out of them the isolate SB19 significantly promoted the growth of kale seedlings in increasement of about 42% of plant height (14.1 cm), 148% of leaf area ($19.0cm^2$) and 138% of shoot fresh weight (1662.5 mg) attained by the bacterially treated plants compared to distilled water treated control (9.9 cm, $7.7cm^2$, 698.8 mg). Shoot water content of SB19 treated kale seedlings (1393.8 mg) was also increased about 152% compared with control (552.5 mg). The SB19 isolated from bulk soil of kale plant in Iksan, Korea, was identified as species of Bacillus based on 16S rRNA gene sequencing analysis. We evaluated the effect of drought tolerance by the Bacillus sp. SB19 on kale seedlings at 7th and 14th days following the onset of the water stress and watering was only at 7th day in the middle of test. In the survey of 7th and 14th day, there were mitigation effect of drought stress in kale seedlings treated with $10^6$ and $10^7cell\;mL^{-1}$ of SB19 compared to distilled water treated control. Especially, there were more effective mitigation of drought damage in kale seedlings treated with $10^7cell\;mL^{-1}$ than $10^6cell\;mL^{-1}$. Further, although drought injury of bacterially treated kale seedlings were not improved at 14th day compared with 7th day, drought injury of $10^7cell\;mL^{-1}$ of SB19 treated kale seedlings were not happen rapidly but developed over a longer period of time than $10^6cell\;mL^{-1}$ of SB19 or control. The diffidence of results might be caused by the concentration of bacterial suspension. This study suggests that beneficial plant-microbe interaction could be a important role of enhancement of water availability and also provide a good method for improving quality of leafy vegetables under water stress conditions.

• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.11-18
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• 2006

Salt stress is one of major environmental factors influencing plant growth and development. To identify salt tolerance determinants in higher plants, a large-scale screen was conducted with a bialaphos marker-based T-DNA insertional collection of Arabidopsis ecotype C24 mutants. One line for salt stress-sensitive mutant (referred to as ssm1) exhibited increased sensitivity to both ionic (NaCl) and nonionic (mannitol) osmotic stress in a root growth assay. This result suggests that ssm1 mutant is involved in ion homeostasis and osmotic compensation in plant. Molecular cloning of the genomic DNA flanking T-DNA insert of ssm1 mutant was achieved by mutant genomic DNA library screening. T-DNA insertion appeared in the first exon of an open reading frame on F3M18.7, which is the same as AtSYP61. SSM1 is SYP61/OSM1 that is a member of the SNARE superfamily of proteins required for vesicular/target membrane fusions and factor related to abiotic stress.

• Journal of Korean Society of Forest Science
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• v.39 no.1
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• pp.47-56
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• 1978

This study aimed to know difference in freezing resistance among different clonal seedlings or different seed source seedlings of Cryptomeria japonica which has been selected where extreme cold prevails in Korea and Japan. The freezing resistance of three 12-50 year old trees was also measured in the experiment. The freezing resistance was measured in different tissue parts: mainly leaf, cambiam and xylem, at three different collection dates in two different collection places during the winter of 1977-1978. The following results and discussions were made: 1. The clonal difference in freezing resistance of Cryptomeria japonica was $9^{\circ}$ to $15^{\circ}C$ in maximum according to the collection place. However, the clonal difference in freezing resistance was not related to the difference in climatic conditions where the parent tree have been growing. This impiled that the natural selection of cold resistant genes in Cryptomeria japonica has not reached its evolutional equilibrium yet since most of the Cryptomeria forest has been established by artificial regeneration. 2. The difference in freezing resistance among leaf, cambium and xylem was not apparent except that leaf of several clones showed higher freezing resistance than cambium or xylem when they collected at mid-winter. The least freezing resistant tissue part, thought its freezing resistance was not measure in all clones and all temperatures were appeared in the apical buds. The new shoot growth was observed in the next spring with being replaced by its dormant or adventitious bud growth when the apical bud was injured dy cold during winter. 3. The freezing resistance of leaf, cambium and xylem was shown high enough so that freezing resistance Cryptomeria clones in this experiment were supposed to be able to survive in cold winter conditions at the middle part of Korea. However, it was reported that the most susceptible tissue part to winter injury was the basal stem, but of which freezing resistance was not-measured in this experiment. Several silvicultural methods for prevention of Cryptomeria seedlings from cold damage were discussed in literature.

• Tuberculosis and Respiratory Diseases
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• v.46 no.5
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• pp.618-627
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• 1999

Background : Rifampicin (RFP) is a key component of the antituberculous short-course chemotherapy. Usually the RFP resistant M.tuberculosis is also resistant to isoniazid (INH), so the RFP resistance is the marker of multi-drug resistant (MDR) tuberculosis. But unusual cases of mono-RFP-resistant tuberculosis have been recently reported with increasing frequency, especially associated with HIV infection in western countries. Therefore, we conducted a retrospective study to investigate the frequency, causes, and the clinical characteristics of mono-RFP-resistant tuberculosis in Korea. Methods : Of the bacteriologically confirmed and susceptibility-proven 699 pulmonary tuberculosis patients (921 isolates) who visited Asan Medical Center from January 1990 to August 1997, eighteen patients with INH-susceptible and RFP-resistant tuberculosis were evaluated. Previous history of tuberculosis, antituberculous drug compliances, associated systemic illness, drug susceptibility patterns, and clinical outcomes were analysed. And rpoB gene sequencing was done in 6 clinical isolates of M. tuberculosis. Results : The mean age of 18 patients was $43{\pm}14$ years, and the sex ratio is 12:6 (M : F). Sixteen (89%) patients had previous history of tuberculosis. None had diagnosed gastrointestinal disorders, and 2 HIV tests that were performed came out negative. Susceptibility tests were done repeatedly in eleven patients, and six (55%) were mono-RFP resistant repeatedly while five (45%) evolved to MDR tuberculosis. Eight (44%) patients were cured, six (33%) failed, three (17%) were lost to follow-up, and the other one is now on treatment. rpoB gene sequencing showed 5 mutations, codon 531 TCG to TIG mutation in 4 isolates and 526 CAC to TAC in 1 isolate. Conclusion : The clinical characteristics of mono-RFP resistant tuberculosis were similar to that of MDR tuberculosis in Korea where the HIV infection rate is lower than western countries. But some patients with mono-RFP-resistant tuberculous could be cured by primary drug regimens including RFP, suggesting that mono-RFP-resistant tuberculous is a different entity from MDR tuberculosis.

• Childhood Kidney Diseases
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• v.15 no.2
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• pp.138-145
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• 2011

Purpose : To test whether the expression of ${\beta}$-catenin, a component of podocyte as a filtration molecule, would be altered by puromycin aminonucleoside (PAN) in the cultured podocyte in vitro. Methods : We cultured rat glomerular epithelial cells (GEpC) with various concentrations of PAN and examined the distribution of ${\beta}$-catenin by confocal microscope and measured the change of ${\beta}$-catenin expression by Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR). Results :We found that ${\beta}$-catenin relocalized from peripheral cytoplasm to inner cytoplasm, therefore, intercellular separations were seen in confluently cultured cells by high concentrations of PAN in immunofluorescence views. In Western blotting of GEpC, PAN ($50{\mu}g/mL$) decreased ${\beta}$-catenin expression by 34.9% at 24 hrs and 34.3% at 48 hrs, compared to those in without PAN condition (P<0.05). In RT-PCR, high concentrations ($50{\mu}g/mL$) of PAN also decreased ${\beta}$-catenin mRNA expression similar to protein suppression by 25.4% at 24 hrs and 51.8% at 48 hrs (P<0.05). Conclusion : Exposure of podocytes to PAN in vitro relocates ${\beta}$-catenin internally and reduces ${\beta}$-catenin mRNA and protein expression, which could explain the development of proteinuria in experimental PAN-induced nephropathy.

• Research in Plant Disease
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• v.22 no.4
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• pp.227-235
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• 2016

Plant disease caused by root-knot nematode is a major problem in crop production. Using of chemical pesticides, one of the most efficient methods to control nematodes, have raised issues in toxicity to humans and animals and environmental pollution. In this study, to select actinomycete strains that have potential to serve as a microbial agent for control of nematodes, we investigated nematicidal activity of culture broth from 670 Streptomyces isolates. A culture filtrate of KRA15-528 isolate that was identified as S. flavogriseus on the basis of 16S rRNA sequence analysis, showed strong nematicidal activity against second stage of juveniles of Meloidogyne incognita and inhibited egg hatching; exposure to 10% of culture filtrate resulted in 71% juvenile mortality at 48 hours afters treatment and suppressed egg hatching by 54% at 9 days after treatment. When the KRA15-528 culture filtrate was partitioned with ethyl acetate and butanol, ethyl acetate layer exclusively showed strong activity; 91%, 53%, 30% of mortality at 1,000, 500, $250{\mu}g/ml$, respectively. Additionally, the culture filtrate suppressed gall formation on cucumber plant by M. incognita with no phytotoxicity. These results suggest that S. flavogriseus KRA15-528 has potential to serve as a microbial nematicide for the control of root-knot nematode disease.

• Korean Journal of Ichthyology
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• v.23 no.4
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• pp.288-299
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• 2011

Freshwater fish fauna and community structure were surveyed through 21 lakes in the Yeungnam area including Gyeongsangbukdo and Gyeongsangnamdo provinces, Korean Peninsula from April 2008 to October 2009. Among 21 lakes, 16 lakes belong to the Nakdong River and 5 are independent drainages. From the present study, 61 species (44 genera, 15 families) were collected including 32 cyprinid species (52.5%), 6 cobitid species (9.8%) and so on. The dominant and subdominant species in aspect of the number of individuals were Hypomesus nipponensis (26.6%) and Squalidus gracilis majimae (14.8%), respectively. On the other hand, in aspect of in biomass, dominant and subdominant species were Lepomis macrochirus (19.8%) and Cyprinus carpio (14.7%), respectively. Among 61 examined species, there were found 20 Korean endemic species and 2 Korean endangered species (Pseudobagrus brevicorpus and Pungitius kaibarae). P. brevicorpus was found in Yongyeonji and Yeongcheonho, and P. kaibarae in Yongyeonji. In addition, 5 exotic species were identified such as Cyprinus carpio nudus (leather carp), Carassius cuvieri, Hypophthalmichthys molitrix, Lepomis macrochirus and Micropterus salmoides. Interestingly, a bluegill L. machrochirus appeared dominant or subdominant species in 5 of 21 examined lakes. Five species introduced from the other rivers in Korean Peninsula were additionally described. In the present study, it was first reported that Micropercops swinhonis inhabits in the Nakdong river basin. The fish species diversity, evenness and dominant indices were examined, and a dendrogram based on similarity indices of inhabiting species among the 21 examined lakes was constructed and discussed.

• Journal of Korean Society of Forest Science
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• v.83 no.2
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• pp.148-154
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• 1994

As a vegetative propagation method for ash species, which is a dioecism and a long cycle of fructification, cut-stem was soaked in water to induce adventitious sprouts, and 2-year-old ash seedling was cut in a nursery to induce adventitious sprouts. We obtained the 1,019 adventitious sprouts from branches of 101 plus trees througout the country. The mean ortet-age is 48. There is not a correlation between ortet ages and production of adventitious sprouts. These sprouts were placed in a cutting bed for rooting. Root ability varied with environmental factors of cuttings. The best rooting(87%) resulted from cutting performed in a vinyl-plastic greenhouse. Rooting was better on perlite+peat moss(2 : 1) medium than other media tested. The rooting ability was generally higher in 2-year-old ortet than plus tree ortet. In the root development of cuttings the non-container cuttings was better than container cuttings.

• Korean Journal of Poultry Science
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• v.43 no.3
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• pp.149-157
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• 2016

This study was performed to investigate the effects of the stocking density (standard stocking density (SSD, $495cm^2/bird$)) vs. high stocking density (HSD,245cm2/bird) and challenge with lipopolysaccharide (LPS, 5mg/kg BW) on the stress-related physiological indicators in chicks. There was a significant (p<0.05) decrease in body weight, but not in the weight of immune organs, between the SSD and HSD groups. The LPS group resulted in a significant (p<0.05) increase in the weights of the thymus and bursa of fabricius compared with the SSD group. Plasma biochemical components, including aspartate transaminase (AST), alanine transaminase (ALT), blood urea nitrogen, Ca, P, creatine kinase and uric acid, markedly (p<0.05) increased in the LPS birds, although no difference in these parameters was observed between the SSD and HSD birds. Furthermore, the birds challenged with LPS showed a significant (p<0.05) increase in the plasma corticosterone level, although this hormone did not differ between the SSD and HSD groups. In the mRNA expression of pro-inflammatory cytokines, hepatic $IL-1{\beta}$, IL-6 and iNOS in the LPS group significantly (p<0.05) increased compared with those in the SSD group. Thymic mRNA expression of $IL-1{\beta}$, IL-6 and IL-18 in the LPS group also significantly (p<0.05) increased compared with those in the other groups. In addition, mRNA expression of $IL-1{\beta}$ in the bursa of fabricius of the LPS group increased (p<0.05) without affecting the other cytokines. Under high stocking density, thymic $IL-1{\beta}$ was the only cytokine that was up-regulated compared with the SSD group. In conclusion, an acute stress induced by LPS challenge profoundly affected immune organ weight, blood biochemical profiles and pro-inflammatory cytokine expression, while chronic stress did not markedly affect biochemical and immunological parameters, suggesting that chicks under high stocking density could be adapted to prolonged stressors.

• Journal of Chest Surgery
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• v.37 no.8
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• pp.691-701
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• 2004

Background: Tissue hypoxia is a characteristic of many human malignant neoplasms, and hypoxia inducible factor-1 (HIF-1) plays a pivotal role in essential adaptive response to hypoxia, and activates a signal pathway for the expression of the hypoxia-regulated genes, resulting in increased oxygen delivery or facilitating metabolic adaptation to hypoxia. Increased level of HIF-1 a has been reported in many human malignancies, but in esophageal squamous cell carcinoma, the influence of HIF-1 a on tumor biology, including neovascularization, is not still defined. Material and Method: The influence of HIF-1 a expression on angiogenic factors, correlation between the tumor proliferation and HIF-1 a expression, interaction of HIF-1 a expression and p53, and correlation between HIF-1 a expression and clinicopathological prognostic parameters were investigated, using immunohistochemical stains for HIF-1 a, VEGF, CD34, p53, and Ki-67 on 77 cases of resected esophageal squamous cell carcinoma. Result: HIF-1 a expression in cancer cells was found in 33 of 77 esophageal squamous cell carcinoma cases. The 33 cases (42.9%) showed positive stain for HIF-1 a. High HIF-1 a expression was significantly associated with several pathological parameters, such as histologic grade (p=0.032), pathological TMN stage (p=0.002), the depth of tumor invasion (p=0.022), regional lymph node metastasis (p=0.002), distant metastasis (p=0.049), and lymphatic invasion (p=0.004). High HIF-1 a expression had significant VEGF immunoreactivity (p=0.008) and Ki-67 labeling index (p<0.001), but was not correlated with microvascular density within tumors (p=0.088). The high HIF-1 a expression was correlated with aberrant p53 accumulation with a marginal significance (p=0.056). The overall 5-year survival rate was 34.9%. The survival rate of patients with a high HIF-1 a expression was worse than that of patients with low-expression tumors (log-rank test, p=0.0001). High HIF-1 a expression was independent unfavorable factors although statistical significance is marginal in multivariate analysis. Conclusion: It is suggested that (1) high HIF-1 a expression in esophageal squamous cell carcinoma is associated with tumor hypoxia, or with genetic alteration in early carcinogenesis and progressive stages, (2) high HIF-1 a expression may be associated with intratumoral neovascularization through HIF-VEGF pathway, and (3) high HIF-1 a expression is associated with poor prognosis in patients with esophageal squamous cell carcinoma and may playa role as biomarker for regional lymph node metastasis.