• Journal of Environmental Science International
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• v.1 no.1
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• pp.1.1-11
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• 1992

To find heavy metal-specific effects on the photosynthetic apparatus of higher plants, we investigated effects of $CuCl_2$, HgCl_2$ and $ZnCl_2$ on electron transport activity and chlorophyll fluorescence induction kinetics of chloroplasts isolated from barley seedlings. Effects on some related processes such as germination, growth and photosynthetic pigments of the test plants were also studied. Germination and growth rate were inhibited in a concentration-dependent manner by these metals. Mercury was shown to be the most potent inhibitor of germination, growth and biosynthesis of photosynthetic pigments of barley plants. In the inhibition of electron transport activity, quantum yield of PS II, and chlorophyll fluorescence induction kinetics of chloroplasts isolated from barley seedlings, mercury chloride showed more pronounced effects than other two metals. Contrary to the effects of other two metals, mercury chloride increased variable fluorescence significantly and abolished qE in the fluorescence induction kinetics from broken chloroplasts of barley seedlings. This increase in variable fluorescence is due to the inhibition of the electron transport chain after PS ll and the following dark reactions. The inhibition of qE could be attributed to the interruption of pH formation and do-epoxidation of violaxathin to zeaxanthin in thylakoids by mercury. This unique effect of mercury on chlorophyll fluorescence induction pattern could be used as a good indicator for testing the presence and/or the concentration of mercury in the samples contaminated with heavy metals.

• Journal of Plant Biology
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• v.30 no.3
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• pp.181-187
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• 1987

Copper inhibited PSII-mediated O2 evolution (H2OlongrightarrowDCIP, H2OlongrightarrowSiMo) but not PSImediated O2 uptake(DCIP. Asc.longrightarrowMV) in isolated Chinese cabbage chloroplasts. Copper toxicity on PSII-mediated O2 evolution was higher at alkaline condition than at acidic condition and was inhanced by light illumination after copper treatment. The increased toxicity by light illumination was not recovered by subsequent dark treatment. The inhibitory effect of copper on H2OlongrightarrowDCIP reaction was higher than that on H2OlongrightarrowSiMo reaction. This result suggests that there may be another inhibitory site of copper on PSII other than water oxidizing side of PSII.

• Journal of Plant Biology
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• v.34 no.3
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• pp.215-221
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• 1991

Photoxynthetic properties of polyvinylalcohol (PVA)-immobilized chloroplast especially regarded to stability of photosynthetic electron transport and the fluorescence induction pattern were studied. When isolated spinach chloroplasts were immobilized with PVA, it showed good preservation of photosynthetic electron transport activity, especially PS II activity, during storage at -15$^{\circ}C$, 4$^{\circ}C$ and 2$0^{\circ}C$. And immobilized chloroplasts revealed similar thermostability of whole chain electron transport to free chloroplsts. And the absorption peak of red band of chloroplasts showed the blue-shift of 2-4 nm after immobilization. Fv/Fm ratio of chlorophyll fluorescence slightly decreased after immobilization. White light pulse after continuous light do not induced the additional fluorescence rise. This means chlorophyll fluorescence at room temperature reached to Fmax under continuous light in the immobilized chloroplasts. It seems that PVA may be a good candidate for immobilization matrix for the preservation of photosynthetic function of thylakoids and for the continuous use of chloroplast membranes of higher plants for solar energy storage and conversion.

• Journal of Plant Biology
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• v.36 no.4
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• pp.371-375
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• 1993

$ CO_2$ fixation of isolated intact spinach chloroplasts under saturating light began to decrease after 20 min, and stopped completely after 1 h. To identify the lesion sites for the die off, reconstituted chloroplast system was used with chloroplasts collected at several phases of time course. $ CO_2$ fixation was inhibited in the reconstituted chloroplasts made of thylakoids and stroma in the later phases, but showed a higher degree of inhibition by the participation of thylakoids than that of stroma in the later phases. Measurement of photophosphrylation and NADP reduction revealed that a severed thylakoidal damage was occurred at the later phases. This results indicate that the lesion sites for the die off are in the thylakoid.the thylakoid.

• Journal of Plant Biology
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• v.33 no.2
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• pp.111-118
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• 1990

In order to characterize the chloroplasts of Korean ginseng as a semi-shade plant and radish as a sun plant, effects of growth light intensity on photosynthetic electron transport (PS) activity in chloroplasts and superoxide (O2.-) production in thylakoid membrane by irradiation were investigated. High-light chloroplasts of both plants showed higher PS activities than those grown under ow growth light intensity. High PS II and low PS I activities in ginseng chloroplasts (ratio of PS II/PS I : 1.1) were observed, but radish chloroplasts showed low PS II and high PS I activities (ratio of PS II/PS I : 0.3). PS II activity of both plants was little affected by temperature in range of 15-35$^{\circ}C$. Activities of whole -chain (PS II+I) in ginseng and PS I in radish were increased at high temperature (4$0^{\circ}C$). Preincubation of chloroplasts at 4$0^{\circ}C$ during 30 min, as a mild heat stress, caused rapid decrease in PS II and PS II+I activities of both plants. However PS I activity was not decreased in ginseng and rather increased in radish. O2.- production (NBT reduction) in Mehler reaction in the thylakoid membrane was inhibited by DCMU in both plants. DMBIB inhibited O2.- production in ginseng, but radish was insensitive to DMBIB. Electron flow system in ginseng thylakoid membrane was more susceptible to damage of photooxidation than that of radish.

• BMB Reports
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• v.28 no.6
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• pp.523-526
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• 1995

Administering ${\delta}-aminolevulinic$ acid (ALA) to isolated pea (Pisum sativum L.) chloroplasts resulted in an increase of heme synthesis in the heme branch of the tetrapyrrole pathway. At 0.1 mM ALA, in the presence of 1 mM $FeSO_4$ heme synthesis was stimulated up to 7 fold of that in the absence of $FeSO_4$. N-Methylmesoporphyrin IX (NMMP), a powerful inhibitor of ferrochelatase, inhibited heme synthesis by 95% at one micromolar concentration. The addition of A TP to the chloroplasts caused not only heme synthesis, but Mg-protoporphyrin IX synthesis in the chlorophyll branch of the tetrapyrrole pathway. In the presence of NMMP, however, inhibition of Mg-protoporphyrin IX synthesis was not observed whereas heme synthesis was inhibited completely.

• Journal of Plant Biology
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• v.25 no.4
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• pp.181-188
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• 1982

Chloroplasts isolated from tobacco (Nicotiana tabacum L. cv. Virginia 115) leaves have been transferred into protoplasts of soybean (Glycine max Merr. cv. Jangyeop) suspension-cultured cells with the help of polyethylene glycol (PEG). The increased yield in protoplasts of chloroplast uptake was depended upon the concentration of both PEG 4,000 and PEG 6,000. The highest yield(36%) occurred at 50% of both PEG, and the yield was decreased above this concentration. The rate of uptake with the incubation time was highest at one hour, then decreased. The process of the chloroplast uptake into the protoplasts was similar with that of a protoplast fusion, except forming invagination during uptake.

• Journal of Plant Biology
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• v.28 no.1
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• pp.69-77
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• 1985

The degree of The degree of The degree of ${Zn}^{2+}$ effect on the photosynthetic electron transport and photophosphorylation activities in barley chloroplasts has been tested.${Zn}^{2+}$treatment was done in the 2 ways. One was that it was added into the chloroplasts suspensions isolated from the plants grown under the normal ${Zn}^{2+}$level (10$^{-6}$ M). The other was that the different concentrations of ${Zn}^{2+}$was applied in each growth medium. Then, it was not added into the chloroplasts suspensions isolated from the plants. PS II activity in both way of the treatments was more severely inhibited than PS I by the increment of ${Zn}^{2+}$ concentration. The photophosphorylation activity measured by pH measurement was gradually decreased with the increase of ${Zn}^{2+}$concentration in both ways, too. However, it was shown that M $n^{2+}$ could be near fully overcome the inhibitory effect of ${Zn}^{2+}$in PS II, and $Mg^{2+}$ could also reduce the Z $n^{2+}$ inhibition in the photophosphorylation. In the low concentrations of $Mg^{2+}$ (3 to 5$\times$10$^{-3}$ M) in the suspension, ${Zn}^{2+}$(2$\times$10$^{-5}$ M) could increase the activity of photophosphorylation. As compares to other cations, Z $n^{2+}$ caused less inhibitory effect on the photophosphorylation activity than Cu, Cd, but more than Pb and Ni. It may be assumed that a complex from reaction of Z $n^{2+}$ and mercaptoethanol was produced and it could reduce the stability of CPI band during SDS-PAGE.effect on the photosynthetic electron transport and photophosphorylation activities in barley chloroplasts has been tested. Z $n^{2+}$ treatment was done in the 2 ways. One was that it was added into the chloroplasts suspensions isolated from the plants grown under the normal Z $n^{2+}$ level (10$^{-6}$ M). The other was that the different concentrations of Z $n^{2+}$ was applied in each growth medium. Then, it was not added into the chloroplasts suspensions isolated from the plants. PS II activity in both way of the treatments was more severely inhibited than PS I by the increment of Z $n^{2+}$ concentration. The photophosphorylation activity measured by pH measurement was gradually decreased with the increase of Z $n^{2+}$ concentration in both ways, too. However, it was shown that M $n^{2+}$ could be near fully overcome the inhibitory effect of Z $n^{2+}$ in PS II, and $Mg^{2+}$ could also reduce the Z $n^{2+}$ inhibition in the photophosphorylation. In the low concentrations of $Mg^{2+}$ (3 to 5$\times$10$^{-3}$ M) in the suspension, Z $n^{2+}$ (2$\times$10$^{-5}$ M) could increase the activity of photophosphorylation. As compares to other cations, Z $n^{2+}$ caused less inhibitory effect on the photophosphorylation activity than Cu, Cd, but more than Pb and Ni. It may be assumed that a complex from reaction of Z $n^{2+}$ and mercaptoethanol was produced and it could reduce the stability of CPI band during SDS-PAGE.effect on the photosynthetic electron transport and photophosphorylation activities in barley chloroplasts has been tested. Z $n^{2+}$ treatment was done in the 2 ways. One was that it was added into the chloroplasts suspensions isolated from the plants grown under the normal Z $n^{2+}$ level (10$^{-6}$ M). The other was that the different concentrations of Z $n^{2+}$ was applied in each growth medium. Then, it was not added into the chloroplasts suspensions isolated from the plants. PS II activity in both way of the treatments was more severely inhibited than PS I by the increment of Z $n^{2+}$ concentration. The photophosphorylation activity measured by pH measurement was gradually decreased with the increase of Z $n^{2+}$ concentration in both ways, too. However, it was shown that M $n^{2+}$ could be near fully overcome the inhibitory effect of Z $n^{2+}$ in PS II, and $Mg^{2+}$ could also reduce the Z $n^{2+}$ inhibition in the photophosphorylation. In the low concentrations of $Mg^{2+}$ (3 to 5$\times$10$^{-3}$ M) in the suspension, Z $n^{2+}$ (2$\times$10$^{-5}$ M) could increase the activity of photophosphorylation. As compares to other cations, Z $n^{2+}$ caused less inhibitory effect on the photophosphorylation activity than Cu, Cd, but more than Pb and Ni. It may be assumed that a complex from reaction of Z $n^{2+}$ and mercaptoethanol was produced and it could reduce the stability of CPI band during SDS-PAGE.ld reduce the stability of CPI band during SDS-PAGE.

• Journal of Plant Biology
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• v.31 no.3
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• pp.187-196
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• 1988

Chlorella ellipsoidea were cultured in "cold" media starvated with the nitrate and phsophate sources. The effects of the nitrate and phsophate starvation on the biosynthesis of phospholipid and the composition of fatty acids in chloroplasts isolated from these cells were analyzed. The syntheses of phosphatidylcholine and phosphatidylinositol in the nitrate and phosphate starvation were similarly inhibited as compared with the control but phsophatidylethanolamine synthesis in the nitrate starvation was extremely lower than that in the phosphate starvation. The major fatty acids utilized in phospholipid formation within chloroplasts were palmitic acid and linolenic aicd. However, palmitic acid and stearic acid were dominant in the condition of the nitrate starvation. The levels of palmitic acid were enhanced 3-fold than that of the control. These results suggest that the biosynthesis of phospholipid and the composition of fatty acids were affected by the nitrate and phosphate starvation in the culture media.ure media.

• Research in Plant Disease
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• v.23 no.3
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• pp.288-293
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• 2017

Chrysanthemum chlorotic mottle viroid (CChMVd) fused to the leader sequence of a reporter gene (mRFP) expressed transiently in agroinfiltrated Nicotiana benthamiana, was used to show that CChMVd can traffic into chloroplasts, thought to be the site of its replication. Fluorescence from mRFP was detected in chloroplasts, but only if the viroid transcription fusions were present, either from the full-length 400-nt CChMVd, or each of two partial fragments (nucleotides 125 to 2 and 231 to 372). The mRFP and its mRNA were detected by western blotting and RT-PCR, respectively, in tissue extracts of plants infiltrated by each fusion construct. Isolated chloroplasts were shown by RT-PCR to contain the RNA sequences of both CChMVd and mRFP, if both were present, but not the mRFP sequence in the absence of the viroid sequences. The results suggest that RNA trafficking was probably due to an RNA structure, and not a particular sequence, as discussed.