• Journal of Plant Biotechnology
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• v.30 no.1
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• pp.19-25
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• 2003

Radiation technique in agriculture was initiated to develop mutant rice. Seeds of Daechungbyeo rice were irradiated with 250 Gy gamma ray for the purpose of inducing and selecting rice variants. Some quantitative traits of the variants in M$_{8}$ generation were evaluated and RAPD analysis was carried out. Variants showed a wider range of agronomic characteristics in both a positive and a negative direction compared with their original variety. The new mutants were characterized by an increased or decreased in plant height, lodging resistance and shorter panicle. RAPD analysis showed that polymorphic bands were presented in most of the primers. In comparison with the original variety, variants were classified into four groups through UPGMA analysis. Among mutants no. 91, 139, 140 and 141 was ranked as salt tolerance and the proline content of these mutants was more increased than that of original variety. The lines of 139, 140 and 141 had the highest genetic distance as compared to original variety in the dendrogram. It is expected that such variants will be useful not only for studying molecular genetics but also for breeding research and genetic analysis.s.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.1
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• pp.43-49
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• 2015

This experiment was conducted to evaluate the agronomic characteristics and forage productivity of Italian ryegrass cultivars in Yecheon, Kyeongbuk from 2011 to 2013. The experimental design was a randomized complete block design (RCBD) with three replications. Italian ryegrass cultivars were seeded on Sep. 26 in 2011 and Sep. 25 in 2012. The Italian ryegrass cultivars were harvested on the heading date of the variety. The cold-resistance of domestic cultivars was stronger than other foreign varieties. Among early-maturing cultivars, the dry matter (DM) yield of the "Kowinearly" was 10,031 kg/ha, which was significantly higher than that of other cultivars (p<0.05). In medium-maturing cultivars, the DM yield of the "Kowinmaster" and "Tam 90" were 10,484 and 8,191 kg/ha, respectively. Of the two, the former's DM yield was higher than the latter's (p<0.05). Among late-maturing cultivars, the DM yield of "Hwasan 104" was 10,641 kg/ha, which was similar to that of "Hwasan 101" and significantly higher than the other late-maturing cultivars (p<0.05). According to the results obtained from this study, an early-maturing variety with cold-tolerance and high productivity is required for the paddy field cultivation of an Italian ryegrass cultivar after rice harvest in the mid-northern region of Korea. A medium- or late-maturing variety is more advantageous for the field cultivation of the maximum quantity that is possible. In conclusion, to select which variety/ies to grow, the climate of the growing area, weather conditions, and the cropping system must all be considered.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.2
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• pp.17-26
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• 1979

Comparative tolerance of the new rice varieties from Indicax Japonica cross to elastic and plastic chilling injuries was examined at the 3rd leaf-stage, the most sensitive stage to chilling during nursery, using a chilling chamber set 11\circ C, 13hrs. 20K lux day/5$^{\circ}C$ night. Seedlings were reared until 35 days after seeding in a 26\circ C, 13hrs. day / 18\circ C night chamber except the period of chilling treatment for 0, 3, 4, 6, 8 or 10 days. The new varieties were approximately twice susceptible to elastic injuries, and thrice susceptible to plastic injuries than the Japonica varieties in the term of chilling duration. Among the variables indicating apparant chilling injuries the reduction in dry matter responded most sensitively and differentiated well the varietal difference in chilling resistance even with shorter chilling period. Sequential aspects of the cause and effect relations involved in the development of the apparant chilling injuries are discussed and a schematic diagram is presented as Fig. 5 in the text.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.3
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• pp.239-244
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• 2010

The purpose of this study was to identify mungbean (Vigna radiata L.) cultivars with appropriate characteristics for labor saving culture (whole crop feeding and combine harvesting), and to investigate seed quality in the southern South Korea. Cultivar Dahyeon exhibited strong lodging resistance, excellent disease tolerance, and greater pod numbers per plant resulting in higher yield. Cultivar Owool and Keumseong, the two most common mungbean cultivars in Korea, exhibited lower yield than Dahyeon due to weaker disease tolerance or lower pod numbers per plant. Cultivar Samgang demonstrated higher seed starch content, Jangan, Nampyeong, and Keumseong exhibited higher crude protein content, and Sohyeon exhibited higher vitexin and isovitexin contents. However, no statistical differences were found among the cultivars in crude fat content. Unsaturated fatty acid ranged from 51.8 to 57.2%, with saturated fatty acid ranging from 36.2 to 40.3%. We detected five unsaturated fatty acids including linoleic acid (36.1 to 38.6%), linolenic acid (10.3 to 14.7%), and oleic acid (2.7 to 4.6%), and seven saturated fatty acids including palmitic acid (28.7 to 30.9%), stearic acid (2.9 to 4.1%), and arachidic acid (1.5 to 3.7%). There were significant differences between the cultivars in amylogram properties of seeds: the Nampyeong cultivar exhibited a lower gelatinization temperature; Dahyeon was higher in peak viscosity and breakdown; and Sohyeon, Nampyeong, and Dahyeon were lower in setback.

• The Korean Journal of Physiology
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• v.21 no.2
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• pp.211-223
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• 1987

Head-down tilt (HDT) at $-6^{\circ}$ has been commonly used as the experimental model in both man and animals to induce the blood shift toward the head or central protion of the body, demonstrating similar physiological effect encountered in the weightlessness in the orbital flight. There are few reports about the physiological response upon the cardiovascular regulatory system or the tolerance to the $(-6^{\circ})$ HDT within a relatively short period less than 1 hour. Therefore, the purpose of this study way to observe the effects of $-6^{\circ}$ HDT on cardiovascular system within 30 minutes and to evaluate early regulatory mechanism for simulated hypogravity. Ten mongrel dogs weighing 8-12 kg were anesthetized with the infusion of 1% ${\alpha}-chloralose$ (100 mg/kg) intravenously, and the postural changes were performed from the supine to the $-6^{\circ}$ head-down Position, then from the head-down to the supine (SUP), and each posture was maintained for 30 minutes. Blood flow $({\dot{Q}})$ through common carotid and femoral arteries were determined by the electromagnetic flowmeter. Mean arterial pressure (MAP), heart rate (HR), respiratory rate , and pH, $P_{O_2}$, $P_{CO_2}$ and hematocrit (Hct) of arterial and venous blood were also measured. The peripheral vascular resistance was calculated by dividing respective MAP values by ${\dot{Q}}$ through both sides of common carotid or femoral arteries. The concentration of plasma epinephrine and norepinephrine was determined by Peuler & Johnson's radioenzymatic method. The results are summarized as follows: In the initial 5 minutes in $-6^{\circ}$ HDT, HR was significantly (p<0.05) increased and MAP slightly decreased. Although ${\dot{Q}}$ and carotid peripheral artery resistance were not significantly changed, ${\dot{Q}}$ through femoral artery was diminished and femoral peripheral artery resistance was elevated. In the SUP, the initial changes of MAP and HR were increased (p<0.05), but those of ${\dot{Q}}$ and peripheral vascular resistance through both common carotid and femoral arteries were not significant. After 10 minutes of each postural change in both HDT and SUP, MAP was maintained almost equal to that of the level of pretilting control. During 60 minutes of both postural changes of HDT and SUP, $P_{O_2}$ and Hct were not changed significantly. However pH tended to increase slowly and $P_{CO_2}$ was gradually decreased. The pH and $P_{CO_2}$ seemed to be related to the increased respiratory rate. Plasma epinephrine concentration was not changed significantly and plasma norepinephrine concentration was slightly decreased in the course of HDT and also at 10 minutes of SUP. However these concentration changes were statistically insignificant. From these results, it may be concluded that the effect of $-6^{\circ}$ HDT for 30 minutes on the cardiovascular system and plasma catecholamine levels of the dog is minimum and it is suggestive that the cardiovascular regulatory mechanism, possibly mediated by so called gravity receptors including baroreceptor and volume receptor, has been properly and adequately operated.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.189-192
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• 2001

We have investigated the effects of abiotic and biotic stresses on leaf senescence using transgenic tobacco plants, in which cellular contents of polyamines were increased by introducing the genes of polyamine and ethylene biosynthesis in sense or antisense orientation. These transgenic plants showed accumulations of polyamines at higher levels than were found in wild-type. Stress-induced senescence was attenuated in transgenic plants cpmpared with wild-type plants, in terms of total chlorphyll loss and phenotypic changes after oxidative stress of hydrogen peroxide($H_2O_2$), high salinity, acid stress (pH3.0), ABA and fungal pathogen(phytophothora parasitica pv.Nicotianae). Transcripts for antioxidant enzyme, glutathionine-S-transferase and catalase, were also more abundant in transgenic plants than wild-type plants. These result suggested that higher expression of those genes caused a broad-spectrum resistance to abiotic stress/biotic stress. These phenomena indicate that polyamines may play an important role in contributing to the antioxidant defense function in plants. Our findings suggest that facilitate the improvement of stress tolerance of crop plants.

• Journal of Microbiology and Biotechnology
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• v.30 no.2
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• pp.187-195
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• 2020

To understand the molecular mechanism involved in the survivability of cold-tolerant lactic acid bacteria was of great significance in food processing, since these bacteria play a key role in a variety of low-temperature fermented foods. In this study, the cold-stress response of probiotic Lactobacillus plantarum K25 isolated from Tibetan kefir grains was analyzed by iTRAQ proteomic method. By comparing differentially expressed (DE) protein profiles of the strain incubated at 10℃ and 37℃, 506 DE proteins were identified. The DE proteins involved in carbohydrate, amino acid and fatty acid biosynthesis and metabolism were significantly down-regulated, leading to a specific energy conservation survival mode. The DE proteins related to DNA repair, transcription and translation were up-regulated, implicating change of gene expression and more protein biosynthesis needed in response to cold stress. In addition, two-component system, quorum sensing and ABC (ATP-binding cassette) transporters also participated in cell cold-adaptation process. These findings provide novel insight into the cold-resistance mechanism in L. plantarum with potential application in low temperature fermented or preserved foods.

• Korean Journal of Clinical Laboratory Science
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• v.46 no.1
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• pp.1-11
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• 2014

This research has been performed by our own investigation, also cooperated with Health and Sanification Division and each of district offices in Busan metropolitan city. After choosing, we collected water samples five times for microbiological examination. As a result of investigating in 160 water samples from urban areas, we could detect 88 cases of Vibrio spp. Furthermore, there were four cases exceeding the acceptable limit of aquarium water (100,00/mL) and another four cases exceeding the limit of Coliform group (1,000 below/100 mL). As a result of investigating that we performed for 271 cases of water samples from coastal areas from April to November, we could detect 130 cases of vibrio species and 10 cases of Coliform group. After performing 17 kinds of antibiotic susceptibility test for 41 cases of isolated Vibrio parahaemolyticus, 27 cases showed tolerance to Amplicllin (AM), all of 31 cases showed intermediate resistance only to Cefazolin (CF) but had sensitivity to the rest of them. As a result of performing antibiotic susceptibility test, serum test and PFGE gene analysis on each 10 pair of Vibrio parahaemolyticus detected concurrently from intake-pipe water and, aquarium water, we couldn't get data showing that they are clearly same species in three kinds of test. In addition, UV sterilization, Ozonization and so on. Based on our research, intake pipe didn't have a problem with microbiological contamination so we are sure that the germ came from supplied fish had caused that kind of contamination. For effective management, UV sterilization or Ozonization which can be handled consistently should be adopted in aquarium.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.177-184
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• 2009

Three hundred lactic acid bacteria isolated from human feces were studied their probiotic characters to develop potential probiotics. The properties were tested on the basis of guideline for probiotic selection protocol such as tolerance for acid or bile salt, thermal stability, antimicrobial, anticancer cell, and antiviral activity. Strain Miny-148 was selected as a potential probiotic bacterium which showed resistance to low pH, bile salts and thermal stability. On the basis of fatty acid profiles and 16S rDNA sequences analysis, the strain was identified as Lactobacillus pentosus (similarity 99.9%). The strain, L. pentosus Miny-148, showed broad antimicrobial spectrum against E. coli O157:H7, Shigella flexneri, Bacillus anthracis, Staphylococcus aureus, E. coli, Vibrio cholerae, V. vulnificus, Salmonella typhimurium, and Methicillin-resistant S. aureus (MRSA). Cell-free culture supernatant of the strain also inhibited against the growth of HT-29 colon cancer cell and transmissible gastroenterits virus.

• Journal of Plant Biotechnology
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• v.5 no.1
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• pp.43-49
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• 2003

Resistant cell lines to azetidine-2-carboxylic acid (AZCA) were selected through rice embryo culture after mutagenic treatment of callus irradiated with 30,50,70,90 and 120 Gy. The optimum AZCA concentration for the selection of resistant cell lines was 3 or 4 mM AZCA considering $LD_{50}$ and the fresh weight of callus. Survival rate of the AZCA resistant callus showed remarkable increase in the callus irradiated with 50 and 70 Gy. Regeneration rate of the AZCA resistant callus was much lower on the whole. Ninety and 120 Gy increased the regeneration rate for calli selected from 3 and 4 mM AZCA, respectively. Based on fresh weight, survival rate and regeneration for selection of the AZCA resistant cell line, 50-90 Gy was considered as the optimum range of gamma irradiation. Irradiated calli selected from AZCA were more tolerant to NaCl than those from non-irradiated calli. It suggests that elevated resistance to osmotic stress resulted from mutagenic treatment. The level of free proline content in the AZCA resistant cell line was increased up to 3.5 times compared with that in the control. Proline content in the regenerant derived from the AZCA resistant cell line also increased to 1.7 times that from the control plants regenerated from callus grown in AZCA free medium. Selection of proline overproducing cell lines by in vitro mutagenesis was successful and seems to be useful for improvement of stress tolerance in this crop.