• Applied Biological Chemistry
• /
• v.34 no.2
• /
• pp.162-167
• /
• 1991

In an attempt to explore the mechanistic aspects of chilling injury in plants and their defensive measures against the low temperature stress, the time sequential measurements of pyruvate, superoxide radicals$(O_{\overline{2}})$ and antioxygenic enzymes during whole period of injury-inducing treatment were performed using mostly rice seedlings. Pyruvate was substantialy accumulated in leaf tissues during the exposure period to $5^{\circ}C$ of the seedlings ; the relative extent of the accumulation was increased with increasing time of the cold treatment. When the cold-treated plants were translocated to ambient temperature$({\sim}25^{\circ}C)$, the accumulation started to dissipate, concomitantly accompaning a remarkable increase in the $O_{\overline{2}}$ level of tissues. Superoxide dismutase(SOD) and catalase were also activated during post-chilling period, although they showed a considerable lag time for activation. In contrast, glutathione peroxidase, another antioxygenic enzyme in cells, was not activated at all by preceding cold treatment of plants. The uptake of exogenous $O_{\overline{2}}$ by the roots of rice seedlings resulted in increase in the activities of SOD and catalase in root tissues. The supply of $H_2O_2$ to plan st brought about the activation of catalase in situ, while failing to exert any effect on the activation state of glutathione peroxidase. The results obtained in this work suggest that pyruvate accumulation in cells is the direct cause of the overproduction of $O_{\overline{2}}$ and thereby other toxic activated oxygen species, and that SOD and catalase may play a crucial role in the protection of plant cells against active oxygen-mediated chilling injury.

• Korean journal of applied entomology
• /
• v.60 no.2
• /
• pp.193-199
• /
• 2021

Solenopsis japonica, which is belonging to Formicidae in Hymenoptera, is a native ant species in Korea. However, it had not been studied for cold hardiness of S. japonica to understand on its overwintering mechanisms in field so far. Cold tolerance on developmental stages was measured at different cold temperature with various exposure times. Workers showed more survival at 5℃ and 10℃ compared with other stages and elevated cold tolerance when workers were exposed at 15℃ for more than 12h incubation as a rapid cold hardening (RCH) condition. RCH treatment not only increased survival of workers at cold temperatures, but also decreased supercooling point (SCP) and freezing point (FP). RCH group increased the survival rate by 44% at 10℃ compared with Non-RCH group. SCP and FP were depressed from -10.0 to -14.2℃ and from -11.3 to -15.3℃, respectively, after RCH treatment. Cold temperature increased expression level of cold- and stress-related genes such as glycerol kinase and heat shock protein. These results indicate unacclimated cold tolerance of S. japonica and its acclimation to low temperature by RCH.

• Journal of Plant Biotechnology
• /
• v.36 no.1
• /
• pp.75-80
• /
• 2009

In order to develop transgenic sweetpotato plants [Ipomoea batatas (L.) Lam. cv. Yulmi] with enhanced tolerance to oxidative stress, we constructed transformation vectors expressing 2-Cys peroxiredoxin (Prx) gene under the control of the stress-inducible SWPA2 or enhanced 35S promoter (named as SP or EP). Transgenic sweetpotato plants were attempted to generate from embryogenic calli using an Agrobacterium-mediated transformation system. Embryogenic calli gave rise to somatic embryos and then converted into plantlets on MS medium containing 100 mg/L kanamycin. Transgenic plants were regenerated in the same medium. Southern blot analysis confirmed that the Prx gene was inserted into the genome of the plants. To further study we selected the transgenic plant lines with enhanced tolerance against methyl viologen (MV). When sweetpotato leaf discs were subjected to methyl MV at $20{\mu}M$, transgenic plants showed about 40% higher tolerance than non-transgenic or empty vector-transformed plants.

• Korean Journal of Plant Resources
• /
• v.30 no.5
• /
• pp.571-577
• /
• 2017

Abscisic acid (ABA) is an important phytohormone involved in abiotic stress tolerance in plants. The group A bZIP transcription factors play important roles in the ABA signaling pathway in Arabidopsis but little is known about their functions in rice. In our current study, we have isolated and characterized a group A bZIP transcription factor in rice, OsABF3 (Oryza sativa ABA responsive element binding factor 3). We examined the expression patterns of OsABF3 in various tissues and time course analysis after abiotic stress treatments such as drought, salinity, cold, oxidative stress, and ABA in rice. Subcellular localization analysis in maize protoplasts using a GFP fusion vector further indicated that OsABF3 is a nuclear protein. Moreover, in a yeast one-hybrid experiment, OsABF3 was shown to bind to ABA responsive elements (ABREs) and its N-terminal region found to be necessary to transactivate a downstream reporter. A homozygous T-DNA insertional mutant of OsABF3 is more sensitive to salinity, drought, and oxidative stress compared with wild type plants ＆ OsABF3OX plants. In addition, this Osabf3 mutant showed a significantly decreased sensitivity to high levels of ABA at germination and post-germination. Collectively, our present results indicate that OsABF3 functions as a transcriptional regulator that modulates the expression of abiotic stress-responsive genes through an ABA-dependent pathway.

• The Korean Journal of Mycology
• /
• v.48 no.4
• /
• pp.381-388
• /
• 2020

Bioluminescence refers to the production and emission of light in living organisms. This phenomenon arises from luciferase-catalyzed oxidation reaction of luciferin. Bioluminescence is widely observed in marine vertebrates and invertebrates, as well as in some microorganisms and fungi. To date, approximately 80 species of fungi have been reported to be luminous. One such example is Omphalotus japonicus, which is a luminous fungus found in Korea. In this study, we examined the bioluminescence of Omphalotus japonicus mycelia. Light emission was detected at the edges of mycelia grown on solid agar medium. Notably, the intensity of bioluminescence was found to be significantly enhanced following wound induction. The increase in light intensity peaked at 3 h after mechanical damage. We also investigated the effects of extreme temperatures on bioluminescence. Unlike mechanical damage, high and low temperatures repressed the light emission from mycelia. Further investigations are required to reveal the physiological and ecological properties of fungal bioluminescent responses to environmental stresses.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2012.05a
• /
• pp.99-101
• /
• 2012

산업현장에서 최종 생산품의 신뢰성 검증단계에 사용되는 PC기반 테스트 장비들은 생산제품의 특성에 따라 인위적인 과전압 인가, 고/저온 테스트, 잦은 강제 셧다운 등 많은 스트레스로 인해 잦은 고장과 오동작을 일으킨다. 테스트 장비의 고장은 생산성 저하와 직결됨으로 신속한 고장원인의 파악을 위한 진단 시스템이 요구된다. 본 논문에서는 테스트 장비의 하드웨어 상태를 효율적으로 진단할 수 있는 하드웨어와 지식정보기반 진단결과의 분석을 통한 오류원인 및 불량파트의 범위를 줄여줄 수 있는 분석 소프트웨어를 제안한다.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.445-446
• /
• 2015

본 논문은 지중송전 케이블 접속함의 이종 절연물에 대한 계면압력 측정에 대하여 기술하였다. 일반적으로 지중 송전케이블의 접속함의 경우, 운전 및 외부조건에 따라 절연물간의 계면압력은 변화하게 되고, 특히 저온에서 계면의 절연성능이 저하되면 고장발생 가능성이 높아진다. 이러한 계면압력 변화 경향을 파악하기 위하여 본 논문에서는 유압 시험을 통해 접속함 조립 시의 초기 계면압력을 측정하였고 그 결과를 기술하였다. 또한 응력 시뮬레이션과 유압 측정값을 비교하여 이론 및 실측값에 대한 신뢰성을 확보하였다.

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 2002.04a
• /
• pp.48-50
• /
• 2002

오이의 원산지는 열대지방으로 생육 적온이 25-3$0^{\circ}C$ 정도로 매우 높다. 그러나 사계절이 뚜렷한 국내 기후 특성 상 생육적온 이하의 환경과 이상의 환경을 경험하게 된다. 시설오이는 온실에서 재배되기 때문에 계절에 따라 고온과 저온 스트레스를 받기 쉽다. 이 가운데 환기를 적극적으로 실시하는 여름철과 봄, 가을에는 밀폐된 공간의 특성상 열집적현상으로 환기가 제대로 이루어지지 않아 고온장해를 받는 경우가 많다. (중략)

• KOREAN POULTRY JOURNAL
• /
• v.25 no.9 s.287
• /
• pp.119-123
• /
• 1993

요즈음 날씨같이 낮에는 전형적인 혹서기를 나타내나 밤이되면 썰렁해져서 자다가도 이불을 찾게 되는데 이런 경우 병아리는 어떤 영향을 받게될까? 병아리날개는 피부보다도 더 예민하여 저온 스트레스를 받게되면 금방 흉터가 생기게 되며 이는 환우를 할때까지 없어지지 않는다. 또한 복부를 덮고 있는 피부는 종이같이 얇으며, 자체 체온조절기능이 미숙하여 외부의 기온영향을 장기에 바로 받게된다. 번개가 치고 난 이후 변압기 등이 손상되었을때 폐사가 많이 나는 이유도 이런데 있는 것이다. 온도관리가 그만큼 중요하다는 이야기이며 성장과도 직결되는 문제이다. 그러나 계절차이, 일교차, 수용시설, 수용수수 과다 등으로 실제 온도관리는 어려움도 많이 따르며 제대로 되지 않는 경우도 많이 볼 수가 있다. 더군다나 요즘같은 날씨에서는 더욱더 그러하다. 병아리는 입추 후 어느 일령에 다다르면 원래 가지고 있던 솜털을 벗으면서 첫번째 환우를 하게되는데 이것으로 병아리 상태파악과 관리에 응용할 수 있는 방법은 없을까?

• Korean Journal of Materials Research
• /
• v.5 no.6
• /
• pp.709-709
• /
• 1995

원거리 플라즈마 화학증착법을 이용하여 저온에서 이산화규소박막을 제조하였다. 본 연구 에서는 공정변수인 기판의 온도, 반응기체의 조성 및 분압과 플라즈마 전력에 따른 산화막의 재료적인 물성을 평가하였다. XPS결과에서 산화막은 양론비(O/Si=2)보다 약간 적어 실리콘이 많이 함유된 막으로 나타났다. 이 경우 굴절율과 ESR분석에 의해 미결합된 실리콘의 양이 증가함을 알 수 있었다. SIMS분석에 의해 미량의 질소성분이 계면에 존재하는 것과 실리콘 미결함을 관찰하였다. FT-IR로부터 막내 수소량을 정량화하였으며 결합각 분포는 200℃이상에서 열산화막과 비슷한 값을 얻었다. 하지만 열산화막에 비해 높은 식각율을 보여 계면 스트레스에 의해 막내의 결합력이 약해진 것으로 생각된다.