• Journal of Ecology and Environment
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• v.29 no.5
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• pp.479-484
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• 2006

Ecophysiological parameters of non-transgenic sweetpotato (NT) and transgenic sweetpotato (SSA) plants were compared to evaluate their resistance to multiple environmental stresses. Stomatal conductance and transpiration rate in NT plants decreased markedly from Day 6 after water was withheld, whereas those values in SSA plants showed relatively higher level during this period. Osmotic potential in SSA plants was reduced more negatively as leaf water potential decreased from Day 8 after dehydration treatment, while such reduction was not shown in NT plants under water stressed condition. SSA plants showed less membrane damage than in NT plants. As water stress and high light stress, were synchronously applied to NT and SSA plants maximal photochemical efficiency of PS II ($F_v/F_m$) in NT plants markedly decreased, while that in SSA plants was maintained relatively higher level. This trend of changes in $F_v/F_m$ between SSA plants and NT plants was more conspicuous as simultaneously treated with water stress, high light and high temperature stress. These results indicate that SSA plants are more resistive than NT plants to multiple environmental stresses and the enhanced resistive characteristics in SSA plants are based on osmotic adjustment under water stress condition and tolerance of membrane.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.4
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• pp.322-325
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• 2003

Controlled hydration treatment of tobacco seeds enhanced seed performance greatly without additional materials associated with conventional osmotic or solid matrix priming technique. The seeds were hydrated by adding water to a level from 10 to 60% by 5% increments and incubated for 8 days at $25^{\circ}C$. After the treatment, the seeds were dried to the original seed moisture content under $20^{\circ}C$ for 72 hours. The moisture content of tobacco seeds equivalent to 35% by the hydration treatment gave the greatest improvement in germination rate and speed compared to untreated or polyethylene glycol (PEG) primed seeds, especially at low temperature of $15^{\circ}C$.

• Journal of Korea Association of Health Promotion
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• v.3 no.1
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• pp.55-61
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• 2005

Functional constipation is regarded as a long-standing symptomatic manifestation of abnormal defecation expressed by either a reduced frequency of bowel movements and /or an altered act of evacuation. Patients with constipation can be treated with laxatives, diets and regular habits. Thorough evaluation of functional constipation is considered in those in whom conservative treatment with dietary advice and use of laxatives fails. Patients with normal colonic transit and normal anorectal function may only need reassurance, education and dietary advice with fiber supplementation. For constipated patients in whom such treatment modalities fail, laxatives including bulk-forming and osmotic agents may be used Although most laxatives, if used intermittently, are relatively safe, they must be chosen bearing in mind possible side effects, patient compliance and their action mechanisms. A subgroup of patients with slow transit through the colon ay be unresponsive to conventional laxatives, and, in these subjects, a trial with enteroprokinetics and sometimes stimulant laxatives should be attempted. This article presents our view of the assessment and pharmacologic treatment of functional constipation.

• Proceedings of the Korean Society of Crop Science Conference
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• 1995.05a
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• pp.96-97
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• 1995

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.321-324
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• 2000

Cell culture of Angelica gigas Nakai producing decursin and decursinol angelate as secondary metabolites were preserved in liquid nitrogen after pre-freezing in deep $freezer(-70^{\circ}C)$. The development of optimal procedure for cryopreservation was investigated by using cryoprotectant and pre-treatment before cooling. 0.7 M sucrose was found be the optimum osmotic pre-conditioning culture medium compared to mannitol, sorbitol and NaCl with the same osmotic pressure. In pre-culture medium, cells in exponential phase, supported the best growth after cryopreservation. Effective cryoprotectant was proved to be a mixture of sucrose, glycerol, DMSO. Higher concentration of cryoprotectant was better for cell viability. The highest relative cell viability established after the development of optimal procedure was 65%.

• BMB Reports
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• v.42 no.1
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• pp.28-34
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• 2009

To understand the molecular mechanism underlying proline accumulation in Brassica napus, cDNAs encoding ${\Delta}^1$-pyrroline-5-carboxylate synthetase (BnP5CS), ornithine $\delta$-aminotransferase (BnOAT) and proline dehydrogenase (BnPDH) were isolated and characterized. Southern blot analysis of BnP5CSs in B. napus and its diploid ancestors suggested a gene loss may have occurred during evolution. The expression of BnP5CS1 and BnP5CS2 was induced, while the expression of BnPDH was inhibited under salt stress, ABA treatment and dehydration, prior to proline accumulation. The upregulation of BnOAT expression was only detected during prolonged severe osmotic stress. Our results indicate that stress-induced proline accumulation in B. napus results from the reciprocal action of activated biosynthesis and inhibited proline degradation. Whether the ornithine pathway is activated depends on the severity of stress. During development, proline content was high in reproductive organs and was accompanied by markedly high expression of BnP5CS and BnPDH, suggesting possible roles of proline during flower development.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.4
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• pp.329-344
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• 1997

To improve germination and growth of forages of hill pasture seeds of several forages were osmotically primed with polyethylene glycol (PEG) under different PEG concentrations, treatment periods, and temperatures. Seeds were coated with several materials, and tested for germination. The best primed or coated seeds in germination tests were surface sow on hilly area. The results obtained are summarized as follows; 1. Osmotic priming with PEG accelerated germination of forages and reduced time taken for germination. 2. Germinability was best when the seeds of Tama ryegrass or orchardgrass were treated for 6-9 days at 30g PEG1100 ml water, red clover or white clover for 3, or 9 days in 20g PEG1100 ml water at $10^{\circ}C$. 3. Priming seeds of Tama ryegrass or orchardgrass in 30% PEG solution for 6 days, and seeds of red clover or white clover in 20% PEG solution for 6 days at $15^{\circ}C$ were most effective in germination, similar to priming at $10^{\circ}C$ . 4. Priming seeds of Tama ryegrass at 15C, and orchardgrass, red clover, or white clover at $10^{\circ}C$ were effective in germination than priming at other temperatures. 5. Osmotic priming with PEG accelerated germination of forages compared to coated seeds in Petri-dishes, while coated seeds germinated more slowly, but showed better emergence and superior growth to those of primed or intact seeds in the field. 6. Priming seeds increased yield slightly, and coating seeds significantly increased its yield on hilly area.

• Mycobiology
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• v.37 no.3
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• pp.161-170
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• 2009

Cryptococcus neoformans is a basidiomycete human fungal pathogen that causes meningoencephalitis in both immunocompromised and immunocompetent individuals. The ability to sense and respond to diverse extracellular signals is essential for the pathogen to infect and cause disease in the host. Four major stress-activated signaling (SAS) pathways have been characterized in C. neoformans, including the HOG (high osmolarity glycerol response), PKC/Mpk1 MAPK (mitogen-activated protein kinase), calcium-dependent calcineurin, and RAS signaling pathways. The HOG pathway in C. neoformans not only controls responses to diverse environmental stresses, including osmotic shock, UV irradiation, oxidative stress, heavy metal stress, antifungal drugs, toxic metabolites, and high temperature, but also regulates ergosterol biosynthesis. The PKC(protein kinase C)/Mpk1 pathway in C. neoformans is involved in a variety of stress responses, including osmotic, oxidative, and nitrosative stresses and breaches of cell wall integrity. The $Ca^{2+}$/calmodulin- and Ras-signaling pathways also play critical roles in adaptation to certain environmental stresses, such as high temperature and sexual differentiation. Perturbation of the SAS pathways not only impairs the ability of C. neoformans to resist a variety of environmental stresses during host infection, but also affects production of virulence factors, such as capsule and melanin. A drug(s) capable of targeting signaling components of the SAS pathway will be effective for treatment of cryptococcosis.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.483-483
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• 2012

Recently, nonthermal bioplasma has been attracted by researchers due to their potentials to modulate cellular functions resulting in changes of biomolecular electron band structures as well as cell morphologies. We have investigated the secondary electron emission characteristics from the surface of the erythrocyte, i.e., red blood cell (RBC) with and without the nonthermal bioplasma treatment in morphological and biomolecular aspects. The morphologies have been controlled by osmotic pressure and biomolecular structures were changed by well known reactive oxygen species. Ion-induced secondary electron emission coefficient have been measured by using gamma-focused ion beam (${\gamma}$-FIB) system, based on the quantum mechanical Auger neutralization theory. Our result suggests that the nonthermal bioplasma treatment on biological cells could result in change of the secondary electron emission coefficient characterizing the biomolecular valence band electron energy structures caused by the cell morphologies as well as its surface charge distributions.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.266-274
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• 2010

This study aim to investigate fundamentally the growth and physiological responses of tomato plants in responses to two different levels of water deficit, a weak drought stress (-25 kPa) and a severe drought stress (-100 kPa) in soil. The two levels of water deficit were maintained using a micro-irrigation system consisted of soil sensors for the real-time monitoring of soil water content and irrigation modules in a greenhouse experiment. Soil water contents were fluctuated throughout the 30 days treatment period but differed between the two treatments with the average -47 kPa in -25 kPa set treatment and the -119 kPa in -100 kPa set treatment. There were significant differences in plant height between the two different soil water statuses in plant height without differences of the number of nodes. The plants grown in the severe water-deficit treatment had greater accumulation of biomass than the plants in the weak water-deficit treatment. The severe water-deficit treatment (-119 kPa) also induced greater leaf area and leaf dry weight of the plants than the weak water-deficit treatment did, even though there was no difference in leaf area per unit dry weight. These results of growth parameters tested in this study indicate that the severe drought could cause an adaptation of tomato plants to the drought stress with the enhancement of biomass and leaf expansion without changes of leaf thickness. Greater relative water content of leaves and lower osmotic potential of sap expressed from turgid leaves were recorded in the severe water deficit treatment than in the weak water deficit treatment. This finding also postulated physiological adaptation to be better water status under drought stress. The drought imposition affected significantly on photosynthesis, water use efficiency and stomatal conductance of tomato plants. The severe water-deficit treatment increased PSII activities and water use efficiency, but decreased stomatal conductance than the weak water-deficit treatment. However, there were no differences between the two treatments in total photosynthetic capacity. Finally, there were no differences in the number and biomass of fruits. These results suggested that tomato plants have an ability to make adaptation to water deficit conditions through changes in leaf morphology, osmotic potentials, and water use efficiency as well as PSII activity. These adaptation responses should be considered in the screening of drought tolerance of tomato plants.