• Journal of Life Science
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• v.20 no.8
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• pp.1173-1180
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• 2010

We investigated changes in photosynthesis and activity of ascorbate peroxidase (APX) that scavenges ROS as responses to oxidative stress induced by salinity in rice (Oryza sativa L.). Photosynthetic efficiency of rice leaves, monitored in terms of Fv/Fm, declined with the increase of salt concentration (100-300 mM NaCl). Salinity caused an increase of $H_2O_2$ in leaves of rice, with an increase of APX activity. Among total APX isoforms, an isoform of stromal-APX 1 in leaves of rice was completely inactivated by 300 mM NaCl, but was not affected by chilling or drought. The results suggest that salt stress acts in quite a different mechanism in relation to the activity of stromal-APX from that of other stresses such chilling and drought. We carried out RT-PCR for analysis of genes expression of APX isoforms as affected by salt stress. The expression of cytosolic APX/thylakoid-bound APX genes in leaves of rice exposed to salt stress was increased, while stromal APX gene expression rapidly declined.

• Applied Microscopy
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• v.24 no.4
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• pp.13-31
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• 1994

The fine structure of palisade chloroplasts has been studied in the mature leaves of 3 Dubautia species (D. scabra var. leiophylla, D. knudsenii and D. scabra var. leiophylla${\times}$D. knudsenii) to explore variation at the ultrastructural level, since the parental species exhibit quite different morphological and anatomical features. Types of thylakoidal membrane systems, occurrence and distribution of phytoferritin-like structures, lipid droplets, starch grains, mitochondria and microbodies were examined. Four different types of thylakoidal membranes were found in D. scabra var. leiophylla, 2 rather uniform types in D. knudsenii and 3 intermediate types in their hybrid. D. scabra var. leiophylla and the hybrid were marked by statistically significant differences in mean numbers of thylakoids per granum, while no significant difference was found between D. knudsenii and the hybrid. Phytoferritin-like structures which were about $100-120{\AA}$ in diameter as a whole particle each were found in all 3 species. The amount and distribution of particles varied by species. Lipid droplets, plastoglobuli, and starch grains occurred in all 3 species, but the frequency of starch grains also varied with the species. More frequent and larger starch grains were observed in D. knudsenii than in the other two species. Microbodies, or peroxisome, were observed throughout all species. They occurred, either with or without crystalline inclusions, around the chloroplasts.

• KSBB Journal
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• v.8 no.2
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• pp.115-121
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• 1993

The effect of polyamine on chlorophyll amount, chloroplast peroxidase and chloroplast thylakoid protein in rice leaf segments which were grown for 10 days(16 hrs, light : 8 hrs, dark) in a hormone-free MS medium containing polyamine was studied. Polyamine treatment increased the chlorophyll contents compared with the control in rice leaf segments. Especially spermine was most effective. Also, in rice leaf segments treated with polyamine chloroplast peroxidase activity was higher than in the control. The treatment with lmM of spermidine increased the enzyme activity by 100%. In polyamine treatment and control two major polypeptide bands corresponding to 56 and 25Kd molecular weight were clearly resolved with other minor bands by SDS-PAGE in the insoluble protein fraction. However, in these bands (56, 25Kd), the total area of protein in treating with polyamine were higher than that of the control. These results suggest that polyamine was an important factor in the chloroplast development of rice seedlings.

• ALGAE
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• v.21 no.4
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• pp.479-483
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• 2006

In preparation of the biological samples for electron microscopy, the chemical fixation by glutaraldehyde, paraformaldehyde, and OsO4 has been generally used for a long time. However, the chemical fixation method has some problems: the infiltration time is a little bit long and the ultrastructure of cell or tissue transforms before complete fixation of sample. So, recently, cryo-fixation is considered more often in biomedical field. In this study, we compared High Pressure Freezing (HPF) method with chemical fixation method using a algal sample (Ptilota filicina J. Agardh), which was difficult to fix using chemical fixation method. In chloroplast, the ultrastructure of thylakoid lamella and phycobilisome can not show clearly by chemical fixation. In this study we could observe the ultrastructure of thylakoid lamella and phycobilisome of chloroplast very clearly using HPF fixation. An improved images of ultrastructures of nucleus, mitochondrion and floridean starch could obtain. These results suggest that HPF method is very useful method in algal specimen for electron microscopy.

• Journal of Photoscience
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• v.5 no.1
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• pp.1-10
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• 1998

The susceptibility of chilling-resistant spinach plants. and of chilling-sensitive squash plants to photoinhibition was compared in terms of the activity of photosystem II, in relation to the deuce of fatty acid unsaturation of chloroplast membrane lipids. From thylakoid membranes of the plants. monogalactosyl diacylgtycerol, digalactosyl diacylglycerol. sulfoquinovosyt diacylglycerol, and phosphatidylglycerol were seperated as major lipid classes. It was found that the content of cis-unsaturated fatty acids of phosphatidylglycerol was greater by 32% in spinach than that in squash. When leaf disks were exposed to light at 5$\circ$C, 15$\circ$C and 25$\circ$C, photochemical efficiency of photosystem II. measured as the ratio of the variable to the maximum fluorescence of chlorophyll, declined markedly in squash plants, as compared to spinach plants. When leaf disks were exposed to strong light in the presence of lincomycin, an inhibitor of protein synthesis in chloroplasts, photoinhibition was accelerated in the two types of plants. Moreover, lincomycin treatment abolished the differences in the degree of susceptibility to strong light, which had been observed between the two types of plants. When the extent of photoinhibition of photosystem II-mediated electron transport was compared in thylakoid membranes isolated from the two types of plants, there were no differences in the degree of inactivation of photosystem II activity. However, when intact leaf disks were exposed to strong light either at 10$\circ$C or at 25$\circ$C, and then were allowed to recover either at 17$\circ$C or at 25$\circ$C in dim light. chilling-resistant plants such as spinach and pea showed marked recovery from photoinhibition, in contrast to chilling-sensitive plants, such as squash and sweet potato. whose recovery was strongly dependent on the temperature. These findings are discussed in relation to the unsaturation of fatty acids in membrane phosphatidylglycerol. It appears that fatty acid unsaturation of membrane lipids accelerates the recovery of photosystem H from photoinhibition, without affecting the photo-induced inactivation process of photosystem II associated with photoinhibition.

• Journal of Environmental Science International
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• v.4 no.4
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• pp.335-344
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• 1995

Developmental changes of chlorophyll-protein complexes (CPs) and plastid membrane proteins in greening mung bean cotyledons and the effect of spermine therein were examined by SDS-polyacrylamide gel electrophoresis. The changes in the amounts of CPs became larger with the progress of greening and light-harvesting chlorophyll a/b protein (LHCP) was the main CP in the early greening stage up to f h. As the greening proceeded, chlorophyll-protein of the photosystem I (CPI) accumulated. Application of spermine were effective in accumulating CPs of the thylakoid membrane in the early phase of greening. In the profiles of the plastid membrane proteins, quantitative and qualitative changes were observed with the onset of greening up to 72 h. 56 kD protein of major intensity was observed in all greened chloroplasts and 24 kD protein increased remarkablly in both control and spermine-treated cotyledons. The thylakoids from spermine-treated cotyledons showed hither amounts of thylakoid proteins as compared to the controls. The results suggest that spermine may play a role in the regulation of plastid development and stabilizes the membrane function during greening.

• Journal of Environmental Science International
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• v.4 no.4
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• pp.33-33
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• 1995

Developmental changes of chlorophyll-protein complexes (CPs) and plastid membrane proteins in greening mung bean cotyledons and the effect of spermine therein were examined by SDS-polyacrylamide gel electrophoresis. The changes in the amounts of CPs became larger with the progress of greening and light-harvesting chlorophyll a/b protein (LHCP) was the main CP in the early greening stage up to f h. As the greening proceeded, chlorophyll-protein of the photosystem I (CPI) accumulated. Application of spermine were effective in accumulating CPs of the thylakoid membrane in the early phase of greening. In the profiles of the plastid membrane proteins, quantitative and qualitative changes were observed with the onset of greening up to 72 h. 56 kD protein of major intensity was observed in all greened chloroplasts and 24 kD protein increased remarkablly in both control and spermine-treated cotyledons. The thylakoids from spermine-treated cotyledons showed hither amounts of thylakoid proteins as compared to the controls. The results suggest that spermine may play a role in the regulation of plastid development and stabilizes the membrane function during greening.

• Journal of Photoscience
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• v.9 no.2
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• pp.367-369
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• 2002

Chlorophyll (ChI) a' is the Cl3$^2$-epimer of ChI a which is the constituent of P700, the primary electron donor of Photosystem (PS) I, of a thrmophilic cyanobacterium, Synechococcus elongatus, whose structure was recently determined by X-ray crystallography. To determine whether PS I of diverse oxygenic photosynthetic organisms universally contain one molecule of ChI a ’, pigment compositions of thylakoid membranes and PS I complexes isolated from cyanobacteria, green algae, red algae and higher plants were determined by reversed-phase HPLC. The results show that involvement of one ChI a'molecule in PS I is the universal feature for Chi a-based PS I of oxygenic photosynthetic organisms.

• Ceramist
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• v.21 no.3
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• pp.233-248
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• 2018

Photosynthesis of plant, algae, and certain types of bacteria can convert solar energy to electrons at high efficiency. There have been many research investigations to utilize this mechanism to develop photosynthetic bio-solar energy systems. In this article, the fundamentals of photosynthetic energy conversion mechanism are explained and various approaches are introduced and discussed.

• 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.