• Journal of Plant Biology
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• v.35 no.3
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• pp.247-252
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• 1992

The effect of iso-butanol on the electron transport rate of PS I and PS II was investigated in isolated spinach chloroplasts. In photosystem I, the rate of electron transport increased in the presence of 1 to 4% of isobutanol but decreased in 5 to 9% of iso-butanol. But in photosystem II, the rate of electron transport decreased when treated with 0.2 to 1% of iso-butanol. The inhibitory effect of isomers of butanol on PS II electron transport rate increased in the order of 2-butanol, tert-butanol, iso-butanol and I-butanol. This means that PS II activity was affected according to the arrangement of carbon atoms in butanol. The inhibitory effect of iso-butanol reduced when DPC was added in the solution. This means that iso-butanol affects PS II reduction side of thylakoid membrane primarily. The inhibitory effect of iso-butanol was reduced when $Mn^{2+},\;C^{2+}$ or BSA were added in the solution. PS II activity was restored when 1% iso-butanol treated chloroplast solution was diluted to twentyfold or when $Mn^{2+},\;C^{2+}$ or BSA was added to the diluted solution. However, the SDS-PAGE banding pattern of thylakoid membrane proteins was similar even in 2% iso-butanol treated chloroplasts and the control ones. Only in 5% iso-butanol treated chloroplasts these bands were very weak. These observations suggest that low concentrations of iso-butanol releases manganese and calcium ions from chloroplasts and inhibits the electron transport system. This inhibitory effect can be reversible in low concenterations but in high concentrations the inhibitory effect of iso-butanol become irreversible.rsible.

• 한국전자현미경학회:학술대회논문집
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• 2001.05a
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• pp.25-25
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• 2001

• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.200.1-200
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• 1994

No Abstract, See Full Text

• Journal of Plant Biology
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• v.31 no.3
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• pp.205-215
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• 1988

The effects of simetryne on light induced electron transport and phosphorylation in isolated spinach (Spinacia oleracea L.) chloroplasts were investigated in comparison with sencor and DCMU. Simetryne, like sencor and DCMU, completely, inhibited PSII electron transport and phosphoryltion with 10-6 M treatment but did not inhibit PSI electron transport. Interference with the electron transport pathway was evidenced by the greater sensitivity of oxygen evolution and uptake than phosphorylation. The following order of decreasing inhibitory effectiveness was exihibited; DCMU>simetryne>sencor. The photoacoustic technique was also used to monitor the relative photosynthetic activity in the leaves treated with the herbicides (simetryne, sencor or DCMU) in vivo and in vitro. Photoacoustic measurements on intact leaves provide quantitative information on two related aspects of the photosynthetic process, namely, photochemical energy storage and oxygen evolution. The relative photoacoustic signal of leaves treated with the herbicides showed low level in 21 Hz, but high level in 380 Hz and on isolated chloroplasts (both 21 Hz and 380 Hz) in comparison with that of the untreated leaves. These results suggest that some of photochemical energy is converted into the heat owing to the inhibition of electorn transport pathway by the herbicides.

• Molecules and Cells
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• v.41 no.3
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• pp.161-167
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• 2018

Chloroplasts are present in organisms belonging to the kingdom Plantae. These organelles are thought to have originated from photosynthetic cyanobacteria through endosymbiosis. During endosymbiosis, most cyanobacterial genes were transferred to the host nucleus. Therefore, most chloroplast proteins became encoded in the nuclear genome and must return to the chloroplast after translation. The N-terminal cleavable transit peptide (TP) is necessary and sufficient for the import of nucleus-encoded interior chloroplast proteins. Over the past decade, extensive research on the TP has revealed many important characteristic features of TPs. These studies have also shed light on the question of how the many diverse TPs could have evolved to target specific proteins to the chloroplast. In this review, we summarize the characteristic features of TPs. We also highlight recent advances in our understanding of TP evolution and provide future perspectives about this important research area.

• ALGAE
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• v.25 no.1
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• pp.11-15
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• 2010

Two new genera of red algae, Madagascaria erythrocladioides West et Zuccarello and Pseudoerythrocladia kornmannii West et Kikuchi (Erythropeltidales, Compsopogonophyceae, Rhodophyta), were previously described using molecular analysis and confocal microscopy of isolates in laboratory culture. We examined the ultrastructure of both genera to compare with ultrastructure of other members of the class Compsopogonophyceae. Both genera had Golgi bodies not associated with mitochondria and chloroplasts with a peripheral encircling thylakoid similar to all other members of the class studied thus far. Confocal autofluorescence images showed that Madagascaria has a single round central pyrenoid while Pseudoerythrocladia has no pyrenoid. Our electron microscopic work confirms these initial observations. Tables and keys are presented that assist in interpreting cellular details of genera in the class Compsopogonophyceae.

• Journal of Plant Biology
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• v.37 no.1
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• pp.37-42
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• 1994

Correlative changes between photosynthetic O2 exchange rates and room temperature Chl fluorescence were investigated in wheat (Triticum aestivum L.) chloroplasts treated with high temperature for 5 min. With increasing treatment temperature, photosynthetic O2 evolution rate mediated by PSII was decreased, showing 50% inhibition at 38$^{\circ}C$ (I50). But PSI activity measured by O2 uptake rates was stimulated as a function of increasing temperature. Dark level fluorescence (Fo)-temperature (T) analysis showed that fluorescence rising temperature (Tr), critical temperature (Tc), and peak temperature (Tp) was 38, 43, and 52$^{\circ}C$, respectively. Quenching analysis of Chl fluorescence showed that both the oxidized fraction of plastoquinone (qQ) and degree of thylakoid membrane energization (qNP) increased up to 4$0^{\circ}C$ and then declined dramatically. These results suggest that Tr is correlated with temperature showing a 50% of inhibition of photosynthesis and under mild high temperature stress, qNP is worth regarding as indicator for heat-induced damage of photosynthesis.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.49-50
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• 2003

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.186-186
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• 2005

• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.195.1-195
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• 1994

No Abstract, See Full Text