• Korean Journal of Environmental Biology
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• v.21 no.4
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• pp.400-404
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• 2003

This study was to evaluate the effects of gamma irradiation on the germination, nutrient concentrations and growth of spinach and radish. Both the spinach and radish seeds exhibited relatively higher germination rates in response to the low doses of gamma irradiation compared to the non -irradiated control. Leaf DW of the radish did not respond to gamma irradiation but that of the spinach increased significantly in response to a gamma radiation of 4 Gy (P< 0.05). Leaf growth parameters of the spinach including the leaf area and SLA (leaf area/leaf dry weight) also demonstrated increased responses to gamma irradiation. R/S (root dry weight/shoot dry weight), root DW and root length of the spinach exhibited a positive response to gamma irradiation while those of the radish did not. In contrast, SRL (root length/root dry weight) significantly decreased with gamma irradiation at 8 Gy for the spinach, but not for the radish. The tissue nitrogen concentrations of the spinach showed an increased response to gamma irradiation while that of the radish did not. Furthermore, higher concentrations of phosphorus, potassium, calcium and magnesium were found in the irradiated spinach, but not in the irradiated radish. It seems that the non-specific physiological and/or biochemical activities of spinach might be accelerated by gamma irradiation, possibly accounting for the stimulation of nutrient uptake from the root media and early biomass accumulation in the current study.

• Analytical Science and Technology
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• v.13 no.3
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• pp.315-322
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• 2000

The response characteristics of the bioelectrode developed by the co-immobilization of spinach root tissue and ferrocene in a carbon paste matrix for the amperometric determination of hydrogen peroxide were evaluated. In the range of electrode potential examined (-0.3~0.0V vs. Ag/AgCl). the response time was relatively short ($t_{95%}=11.8$ sec) and it responded in the wide range of pH. Also, its detection limit was $2.25{\times}10^{-6}M$ (S/N=3) and a relative standard deviation of the measurements which were repeated 15 times using $1.0{\times}10^{-3}M$ hydrogen peroxide was 1.87%. The bioelectrode sensitivity decreased to 40% of the original value in 19 days of continuous use.

• Korean Journal of Pharmacognosy
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• v.17 no.2
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• pp.134-138
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• 1986

Based on a tracer study, starch phosphorylase was implicated as an agent in the starch synthesis in sweet potato roots. The enzyme was purified from the tissue as a cluster of isozymes with an average mw of 205K (fresh roots) or 159K (roots stored for 3 mon.). On SDS polyacrylamide gel electrophoresis, one large subunit of 98K mw and several small ones of 47${\sim}57K mw were observed. From the mw data and the results of peptide mapping and immunoelectrophoretic blotting using mono- and polyclonal antibodies, it was deduced that a large part of the large subunit was cleaved at the middle part of the peptide chain to give rise to the small subunits, and on storage, the enzyme molecules were further modified by proteolysis. During the course of phosphorylase purification, a proteinaceous inhibitor of the enzyme was isolated. It had a mw of 250K and was composed of 5 identical subunits of 51K mw. In the direction of starch synthesis, the inhibitor showed a noncompetitive kinetics with a Ki of $1.3{\times}10^{-6}\;M$. By immunohistochemical methods, both the enzyme and the inhibitor were located on the cell wall and amyloplast. Crossreacting materials of the inhibitor were present in spinach leaf, potato tuber and rice grain. These findings indicate the wide occurrence of the inhibitor and also imply its possible participation in regulating starch phosphorylase activity in vivo.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.1
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• pp.51-58
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• 2002

PSI-H is an intrinsic membrane protein known to be essential for efficient electron flow in PSI complex. We isolated a cDNA clone encoding a PSI-H subunit homolog from Chinese cabbage (Brassica campestris L.). The cDNA, designated bpsaH, had an insert of 435 bp and a full open reading frame that would encode a protein of 145 amino acids. The amino acid sequence deduced from the cDNA sequence is 79.3% identical to that of spinach, suggesting the cDNA most likely encodes Chinese cabbage PSI-H subunit. The bpasH was expressed at high level in leaf tissue and low level in flower bud, whereas it was undetectable in root tissue.