• Molecules and Cells
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• v.20 no.1
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• pp.112-118
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• 2005

It was previously shown that AtNAP1 is a plastidic SufB protein involved in Fe-S cluster assembly in Arabidopsis. In this study, we investigated the effects of depleting SufB protein from plant cells using virus-induced gene silencing (VIGS). VIGS of NbNAP1 encoding a Nicotiana benthamiana homolog of AtNAP1 resulted in a leaf yellowing phenotype. NbNAP1 was expressed ubiquitously in plant tissues with the highest level in roots. A GFP fusion protein of the N-terminal region (M1-V103) of NbNAP1 was targeted to chloroplasts. Depletion of NbNAP1 resulted in reduced numbers of chloroplasts of reduced size. Mitochondria also seemed to be affected. Despite the reduced number and size of the chloroplasts in the NbNAP1 VIGS lines, the expression of many nuclear genes encoding chloroplast-targeted proteins and chlorophyll biosynthesis genes remained unchanged.

• Proceedings of the Plant Resources Society of Korea Conference
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• v.18 no.1
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• pp.156-157
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• 2005

• Journal of Plant Biology
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• v.25 no.3
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• pp.135-151
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• 1982

This investigation was carried out to clarify the changes of pigments and soluble protein, and photosystem II activity in the leaves of barley (${SO}_2$-sensitive) and corn (${SO}_2$-resistant) seedlings induced by the ${SO}_2$ fumigation (10, 50ppm). The pH changes of the leaf extract, the content of sulfite and sulfate, the activities of catalase, peroxidase, and polyphenoloxidase were compared in the leaves of barley and corn seedlings induced by ${SO}_2$ fumigation. The results are summarized as follows: An appreciable effect of pH change of leaf extract by ${SO}_2$ fumigation was observed in barley leaves (pH 6.10 to 5.18), but only a small change occurred in corn leaves (pH 5.66 to 5.50). The same pattern of pH changes was recorded when the solution of 0.2N HCl was added to leaf extract, providing lower buffering capacity of the barley leaves than corn leaves. After 2 hours of exposure to 10 ppm ${SO}_2$, the contents of ${SO}^{2-}_3$ and ${SO}^{2-}_4$ were increased in barley leaves, while only ${SO}^{2-}_4$ increased in corn leaves. After fumigation with 10ppm ${SO}_2$ for 2 hours, barley leaves showed significant decreases in activities of catalase, to 17% peroxidase, to 58%, and polyphenoloxidase, to 88%. Corn leaves showed increases in activities of peroxidase, to 136%, and polyphenoloxidase, to 128%. Absorption spectra of pigments obtained from ${SO}_2$-fumigated leaves were gradually decreased with the fumigation time increases, but the decrease was more significant in barley leaves. Fumigation with 50ppm ${SO}_2$ for 2 hours induced the greatest decomposition in carotenoid, followed by chlorophyll a and then chlorophyll b in barley leaves. The ratio of chlorophyll a/b was decreased from 4.1 to 3.6 in barley leaves, but in corn leaves it was maintained almost a constant level(4.9-4.8). The rate of decomposition of chlorophyll and carotenoid in corn leaves was very slow than those in the barley leaves. Fumigation with 50 ppm ${SO}_2$ for 2 hous, decreased the protein content of barley leaves to 59%, and that of corn leaves to 89%, and the extent of decrease in protein content was greater than that of pigments in barley and corn leaves. The rate of DCIP9dichlorophenol indophenol) photoreduction in ${SO}_2$-fumigated leaves was decreased to 18 and 67% in barley and corn leaves, respectively. However, DCIP photoreduction was considerably recovered about 32 and 92% with the addition of DPC(diphenylcarbazide) as an exogenous electron donor in barley and corn leaves, respectively.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1094-1099
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• 2005

Photosynthetic dinoflagellates contain a water-soluble, light-harvesting antenna called the peridinin-chlorophyll-protein (PCP) complex, which has an apoprotein with no sequence similarity to other known proteins. There are two forms of PCP apoproteins; the 15-kDa short form and the 32- to 35­kDa long form. The present study describes the PCP protein and its cDNA from Alexandrium tamarense. A cDNA library was constructed from mRNA isolated from A. tamarense. The complete PCP cDNA was generated by reverse-transcription coupled to polymerase chain reaction (RT-PCR), together with rapid-amplification of cDNA ends (RACE). The A. tamarense PCP cDNA encoded a 55-amino acid signal peptide and a 313-amino acid mature protein with a calculated mass of 32 kDa, which corresponded to that of the long form of PCP. Phylogenetic analysis indicated that the sequence of A. tamarense PCP did not cluster with the short-form PCPs, to which it was only about $55\%$ identical, but which were $79-83\%$ identical to other long-form PCPs. The deduced amino acid sequence of A. tamarense PCP contains an internal duplication, which suggests the possibility that long-form PCPs arose by gene duplication or by the fusion of genes encoding the short form. The abundance of PCP mRNA changed substantially in response to different light conditions, indicating the possible existence of a photo-acclimation response in A. tamarense.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.3 no.3
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• pp.177-188
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• 1999

The effect of ABA on the chloroplast disassembly of Zea mays was investigated by measuring the changes in the relative distribution of chlorophyll(Chl) between the Chl-protein complexes in ABA treated and untreated sensecting leaves. The reaction center(RC)-light harvesting complex(LHC) regions were rapidly disassembled in the late stage of dark-induced senescence. Plus, during dark-induced senescence, the disassembly of a reaction center of P700 apoproteins containing mainly Chl a was faster than that of a reaction center of LHCI apoproteins containing both Chl a and Chl b. The increase in the relative distribution of Chl-protein complexes in the RC-Core2 in the late stage of senescence was due to the accumulation of core complexes such as CP47/43 and reaction centers including D1/D2 apoproteins disassembled from the RC-Corel containing the dimer of D1/D2 apoproteins. The LHCII region was more stable than the other Chl-protein complexes throughout leaf senscence. Accordingly, it is suggested that the preferential breakdown of Chl a gives rise to the disassembly of Chl a-binding proteins, particularly reaction centers and core complexes during dark-induced senescence, plus the primary target of the photosynthetic apparatus in sensecing leaves would seem to be Chl a along with the proteins associated with Chl a. The application of ABA promoted the disassembly of the P700 apoproteins in the PSI reaction center and the dimer of D1/D2 apoproteins, and the conversion of the trimeric LHCII apoprotein to the monometirc LHCII apoprotein during the middle stage of leaf senescence, thereby suggesting that ABA accelerates the disassembly of both Chl a-binding and Chl a+b-binding proteins, particularly Chl a-binding proteins during the middle stage of leaf senescence.

• Applied Biological Chemistry
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• v.3
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• pp.1-7
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• 1962

In order to study the rate control step in the protein metabolic course of the chlorophyll formation, the transaminase activities which are obtained freely in the extracts of cotyledons of germinating peas at the light and the dark places, are measured in Beckman mopel D.U, spectrophoto meter at 490 mu. In this case, of two enzymatic reaction products; oxalacetic acid and pyruvic acid, the former is converted to pyruvic acid by aniline citrate and after each pyruvate phenyl hydrazones are extracted by toluenes: when this is treated with strong alcoholic alkali, a colored hydrazone is formed and it is measured by above apparatus. The estimated G.O.T. and G.P.T. in the germinated cotyledons at dark and light places considerably differ in their activities; G.O.T. and G.P.T. activities which are formed at the light are more increased than at the dark and also they differ in their rates through germination, though G.O.T. activity increment is smoothly but that of G.P.T. is more sharply, and they are considered to be directly affected to the chlorophyll formation and indirectly to the growth. G.O.T. and G.P.T. in each fractions of cell in the cotyledons should be formed by dissociation of zymogens in the microsomal fractions and it seems to promoted by light. In the formation of the chlorophyll, the protein metabolism occurred mainly in the microsomal fractions and the rate determining step is found at the point where the zymogene that is able to produce G.P.T. is activated, and this activation is promoted by light as noted above.

• Journal of Environmental Science International
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• v.13 no.4
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• pp.359-365
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• 2004

The change of chlorophyll fluorescence parameters, O-J-I-P transients and psbA gene expression were investigated in the leaves of Crinum asiaticum var. japonicum on the natural condition in winter, in order to elucidate physiological responses of photosystem II (PS II) activity to winter stresses. The photochemical efficiencies of PS II, Fv/Fm, were significantly low in winter, contrary to its high value in summer. The values of I -qN and I-qP were lower in midday than at dawn or night both in summer and winter, although their decrease in midday was less in winter than in summer. In the O-J-I-P transients, the fluorescence intensity of J, I, P-step decreased remarkably depending on temperature drop in winter. And the D I reaction center protein of PS II decreased in late winter more than in early winter, concomitantly with relatively high content of description products of psbA gene in midday. These results indicate that low temperature in winter causes irreversible damage to PS II and subsequently leads to cell death.

• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.2
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• pp.175-180
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• 2003

Changes in biochemical constituents and physiological alteration were studied in various intensities (1-5%, 6-15%, 16-30%, 31-50% and ＞ 50%) of leaf spot (Myrothecium roridum) on mulberry leaves and compared with healthy leaves. Chlorophyll, total soluble sugar and total protein were decreased (P ＜ 0.01), but total phenol increased due to pathogen infection. Changes in biochemical constituents showed significant correlation with intensity of disease. Chlorophyll ($r^2$= 0.92), and protein (($r^2$= 0.83) possessed negative while phenol (($r^2$= 0.61) possessed positive correlation. Photosynthetic rate, transpiration rate, stomatal conductance, moisture content (%) and physiological water use efficiency (pWUE) were decreased, but stomatal resistance increased in the infected leaves. Physiological parameters also possessed significant (P ＜ 0.01) correlation with disease intensity. Photosynthetic rate (($r^2$= 0.96), transpiration rate ($r^2$=0.88), stomatal conductance (($r^2$= = 0.65), physiological water use efficiency (($r^2$= 0.88) and moisture content (r = 0.85) were negatively but stomatal resistance (($r^2$= 0.75) was positively correlated to disease intensities.

• Mycobiology
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• v.51 no.5
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• pp.343-353
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• 2023

Lichens play crucial roles in the ecosystems, contributing to soil formation and nutrient cycling, and being used in biomonitoring efforts to assess the sustainability of ecosystems including air quality. Previous studies on heavy metal accumulation in lichens have mostly relied on manipulated environments, such as transplanted lichens, leaving us with a dearth of research on how lichens physiologically respond to heavy metal exposure in their natural habitats. To fill this knowledge gap, we investigated lichens from two of South Korea's geographically distant regions, Gangwon Province and Jeju Island, and examined whether difference in ambient heavy metal concentrations could be detected through physiological variables, including chlorophyll damage, lipid oxidation, and protein content. The physiological variables of lichens in response to heavy metals differed according to the collection area: Arsenic exerted a significant impact on chlorophyll degradation and protein content. The degree of fatty acid oxidation in lichens was associated with increased Cu concentrations. Our research highlights the value of lichens as a bioindicator, as we found that even small variations in ambient heavy metal concentrations can be detected in natural lichens. Furthermore, our study sheds light on which physiology variables that can be used as indicators of specific heavy metals, underscoring the potential of lichens for future ecology studies.

• Journal of Plant Biology
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• v.39 no.4
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• pp.301-307
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• 1996

The disassembly of Chl-protein complexes during dark-induced senescence (DIS) was investigated using detached third and fourthleaves of 21$\pm$1 day-old Arabidopsis thaliana. Although Chl content decreased linearly after 1 d, a significant decrease of photochemical effeciency (Fv/Fm) was observed after 2 d. In experiments using native green gel electrophoresis of Chl-protein complexes combined with additional two-dimensional SDS-PAGE analysis, we could observe the degradation of both photosystems after 2 d. Although light-harvesting complex(LHC) for PSI (LHCI) was degraded first in PSI complex, small PSII apoproteins including CP47/CP43 and D1/D2 apoproteins were degraded first in PSII complexes. LHC for PSII (LHCII) trimers were stable until 4 d. The level of LHCII monomers was increased until 3 and decreased thereafter, resulting in the increase of free pigments. These results suggest that the disassembly process of PSI is different from that of PSII.