A chloroplast-localized DEAD-box RNA helicaseAtRH3 is essential for intron splicing and plays an important role in the growth and stress response in Arabidopsis thaliana

Gu, L.,Xu, T.,Lee, K.,Lee, K.H.,Kang, H. Gauthier-Villars ; Elsevier Science Ltd 2014 Vol. No.

Although many DEAD-box RNA helicases (RHs) are targeted to chloroplasts, the functional roles of the majority of RHs are still unknown. Recently, the chloroplast-localized Arabidopsis thaliana AtRH3 has been demonstrated to play important roles in intron splicing, ribosome biogenesis, and seedling growth. To further understand the functional role of AtRH3 in intron splicing and growth and the stress response in Arabidopsis, the newly-generated artificial microRNA-mediated knockdown plants as well as the previously characterized T-DNA tagged rh3-4 mutant were analyzed under normal and stress conditions. The rh3 mutants displayed retarded growth and pale-green phenotypes, and the growth of mutant plants was inhibited severely under salt or cold stress but marginally under dehydration stress conditions. Splicing of several intron-containing chloroplast genes was defective in the mutant plants. Importantly, splicing of ndhA and ndhB genes was severely inhibited in the mutant plants compared with the wild-type plants under salt or cold stress but not under dehydration stress conditions. Moreover, AtRH3 complemented the growth-defect phenotype of the RNA chaperone-deficient Escherichia coli mutant and had the ability to disrupt RNA and DNA base pairs, indicating that AtRH3 possesses RNA chaperone activity. Taken together, these results demonstrate that AtRH3 plays a prominent role in the growth and stress response of Arabidopsis, and suggest that proper splicing of introns governed by RNA chaperone activity of AtRH3 is crucial for chloroplast function and the growth and stress response of plants.

An RRM-containing mei2-like MCT1 plays a negative role in the seed germination and seedling growth of Arabidopsis thaliana in the presence of ABA

Gu, L.,Jung, H.J.,Kwak, K.J.,Dinh, S.N.,Kim, Y.O.,Kang, H. Gauthier-Villars ; Elsevier Science Ltd 2016 Vol. No.

<P>Despite an increasing understanding of the essential role of the Mei2 gene encoding an RNA-binding protein (RBP) in premeiotic DNA synthesis and meiosis in yeasts and animals, the functional roles of the mei2-like genes in plant growth and development are largely unknown. Contrary to other mei2-like RBPs that contain three RNA-recognition motifs (RRMs), the mei2 C-terminal RRM only (MCF) is unique in that it harbors only the last C-terminal RRM. Although MCTs have been implicated to play important roles in plants, their functional roles in stress responses as well as plant growth and development are still unknown. Here, we investigated the expression and functional role of MCT1 (At1g37140) in plant response to abscisic acid (ABA). Confocal analysis of MCT1-GFP-expressing plants revealed that MCT1 is localized to the nucleus. The transcript level of MCT1 was markedly increased upon ABA treatment. Analysis of MCT1-overexpressing transgenic Arabidopsis plants and artificial miRNA-mediated mct1 knockdown mutants demonstrated that Mal inhibited seed germination and cotyledon greening of Arabidopsis plants under ABA. The transcript levels of ABA signaling-related genes, such as ABI3, ABI4, and ABI5, were markedly increased in the MCT1-overexpressing transgenic plant. Collectively, these results suggest that ABA-upregulated MCT1 plays a negative role in Arabidopsis seed germination and seedling growth under ABA by modulating the expression of ABA signaling-related genes. (C) 2016 Elsevier Masson SAS. All rights reserved.</P>

선인장 양심실 보조장치의 설계 및 임상적용을 위한 평가

민병구,박찬영,최재순,이혁수,황창모,김삼성,윤걸중,김종원,선경,이경갑,정종태,김원곤 제주대학교 인공심장이식연구소 2001 인공심장 연구 Vol.2 No.1

현재 개발되고 있는 맥동형 이식형 인공심장은 완전이식형 인공심장과 좌심실보조장치 뿐이다. 좌심실보조장치를 장착한 환자의 10~15%가 우심실의 보조를 필요로하고 완전이식형 인공심장의 장착을 위해서는 자연심장을 제거해야하는 상황에서 이식형 양심실보조장치에 대한 필요성이 대두되고 있다. 본 연구진은 완전이식형 인공심장으로 개발된 한국형 인공심장을 개선하여 양심 실 보조장치를 개발하였다. 양심실보조장치는 이동형 작동기식 미케니즘을 이용하고 있으며 에너지 변환장치와 감속기로 구성된 작동기와 혈액주머니, 그리고 내장형 제어기로 구성되어 있다. 선인장 펌프로 명명된 KAH350은 캐뉼라의 연결을 위한 커넥터를 포함하여 길이 177mm, 폭 164mm, 높이 67 이고 무게 780g이며 최대 심박출량은 5L/min 이다. 양심실보조장치로 개발된 선인장펌프는 좌심실보조장치로도 응용이 가능하다. 이식적합성과 생체적합성을 평가하기 위하여 좌심실보조장치로 5회, 양싱실보조장치로 6회의 동물실험을 수행하였다. 각각 최장 28일간 생존하였으며 11회의 동물실험중 장치의 결함에 의한 것이 3회 있었는데 이들은 모두 전자장치의 결함과 방수처리문제였다. 현재 이식적합성과 일박출량을 향상시킨 KAH400모델이 개발중이다. The types of pulsatile implantable artificial hearts that are on the way of development and have been developed are totally implantable artificial heart and implantable left ventricular assist device (LVAD). Approximately 10% to 15% of all patients Implanted with wearable VADs have required right heart support with another device. And it is reluctant to patient who should remove his or her own heart to be implanted with total artificial heart. These situations drive the development of implantable bi-ventricular assist device (BVAD). The Korean BVAD was develophed by modifying the moving actuator type Korean artificial heart. This electro-mechanical BVAD comprises actuator including energy converter and reduction gear train, blood sacs, and internal motor and energy controllers. The KAH350 which is named as 'Cactus Pump' is 177mm in length, 164mm in width, and 67mm in thickness including connectors and nuts. The weight and maximum cardiac output of Cactus Pump is 780g and 5L/min, respectively. The Cactus Pump that was developed as BVAD could be used as LVAD by attaching compliance caps on the 2 ports of one ventricle. The animal experiments were undergone 5 times for LVAD, and 6 times for BVAD. The best records were 28 days survival in both applications. There were 3 times of device failure and they were all associated with electrical connection and hermetic sealing. The KAH400 that has improved anatomical fitting characterisitcs and stroke volume is on development.

Inhibition of ADP-ribosyl cyclase attenuates angiotensin II-induced cardiac hypertrophy

Gul, R.,Park, J. H.,Kim, S. Y.,Jang, K. Y.,Chae, J. K.,Ko, J. K.,Kim, U. H. Elsevier Science B.V., Amsterdam. 2009 Cardiovascular research Vol.81 No.3

Magnetic and electronic structures of Mn₂As by first principles calculations

Gul Rahman,Sunglae Cho,Soon Cheol Hong 한국자기학회 2005 한국자기학회 학술연구발표회 논문개요집 Vol.15 No.1

Effect of extraction methods on structural, physiochemical and functional properties of dietary fiber from defatted walnut flour

Gul Mali Khan,Nasir Mehmood Khan,Zia Ullah Khan,Farman Ali,Abdul Khaliq Jan,Nawshad Muhammad,Rizwan Elahi 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.4

The effect of different extraction methods i.e. extraction with alkali (AEDF), enzyme (EEDF) and enzyme plus shear emulsifying hydrolysis (SEDF) on structure, physiochemical as well as the functional characteristics of dietary fiber (DF) from defatted walnut flour were studied. AEDF process showed significantly higher (P\0.05) amount of water retention capacity (WRC; 5.39 g/g), water swelling capacity (WSC; 3.16 g/mL), and particle size; while, shown lower value of oil adsorption capacity (OAC; 29 g/g) amongst all. Compared to AEDF, no major differences were observed in network except the matrix in EEDF and SEDF was more porous and honey comb like. DF extracted through AEDF, EEDF and SEDF showed good viscosity and emulsifying activity however, less stability indices. The results from this study suggest that AEDF and EEDF and SEDF had specific effects on the structure-functional properties of DF from defatted walnut flour, which has great potential in food applications.

Ab-initio Study on Magnetism of Al Impurity in bcc Fe

Gul Rahman,In Gee Kim 한국자기학회 2010 한국자기학회 학술연구발표회 논문개요집 Vol.2010 No.12

A First-principles Study on Magnetic and Electronic Properties of Ni Impurity in bcc Fe

Gul Rahman,In Gee Kim 한국자기학회 2008 Journal of Magnetics Vol.13 No.4

The magnetic and electronic properties of Ni impurity in bcc Fe (Ni₁Fe26) are investigated using the full potential linearized augmented plane wave (FLAPW) method based the generalized gradient approximation (GGA). We found that the Ni impurity in bcc Fe increases both the lattice constant and the magnetic moment of bcc Fe. The calculated equilibrium lattice constant of Ni₁Fe26 in the ferromagnetic state was 2.84 A, which is slightly larger than that of bcc Fe (2.83 A). The averaged magnetic moment per atom of Ni₁Fe26 unit cell was calculated to be 2.24 μB, which is greater than that of bcc Fe (2.17 μB). The enhancement of magnetic moment of Ni₁Fe26 is mainly contributed by the nearest neighbor Fe atom of Ni, i.e., Fe1, and this can be explained by the spin flip of Fe1 d states. The density of states shows that Ni impurity forms a virtual bound state (VBS), which is contributed by Ni eg↓ states. We suggest that the VBS caused by the Ni impurity is responsible for the spin flip of Fe1 d states.

A First-principles Study on Magnetism of Al Impurity in bcc Fe

Gul Rahman,In Gee Kim 한국자기학회 2011 Journal of Magnetics Vol.16 No.1

The magnetism and electronic structure of bcc Al₁Fe₂? was investigated by means of first-principles calculations with and without spin-orbit coupling (SOC). From the calculated total energy, the SOC corrected system is shown to be approximately 5 meV per atom lower than the SOC uncorrected system. The induced spin magnetic moment at the Al site was ?0.125 μB without SOC and ?0.124 μB with SOC. The orbital magnetic moments were calculated to be 0.002 μB in [100] direction for Al. The electronic structures showed the nearest neighbor antiferromagnetic interaction between Fe and Al to be essential for determining the magnetism of the Al₁Fe₂? system.

Magnetic and electronic structures of FeAs by first principles calculations

Gul Rahman,Sunglae Cho,Soon Cheol Hong 한국자기학회 2004 한국자기학회 학술연구발표회 논문개요집 Vol.14 No.2