Photosynthetic oxygen evolution by isolated spinach (Spinacia oleracea L.) chloroplasts approached complete inhibition in the presence of a 5 mm concentration of sulfur dioxide. A similar inhibition was observed in the presence of equimolar concentrations of bisulfite ions, suggesting a parallel mode of action. In contrast, an equimolar concentration of sulfite ions was markedly less inhibitory...

Acetyl-coenzyme A (CoA) synthetase was purified 364-fold from leaves of spinach (Spinacia oleracea L.) using ammonium sulfate fractionation followed by ion exchange, dye-ligand, and gel permeation chromatography. The final specific activity was 2.77 units per milligram protein. The average M(r) value of the native enzyme was about 73,000. The Michaelis constants determined for Mg-ATP, acetate, ...

Spinach (Spinacia oleracea, L.) cells in liquid culture release peroxidases. This release is reduced by EGTA and promoted by calcium ions. In a medium deprived of calcium the rate of peroxidase release is low, but immediately after addition of I mM calcium there is a sudden increase of the extracellular peroxidase activity. Extracellular calcium apparently penetrates into the cultured cells rat...

Spinach leaf (Spinacia oleracea L. var. Kyoho) protoplasts sustain protein-synthesizing activity as measured by the incorporation of [(14)C]-leucine into the protein fraction both in the light and in the dark. By the immunoprecipitation of ribulose-1,5-bisphosphate (RuP(2)) carboxylase with rabbit antibody raised against the purified spinach enzyme preparation, it was found that approximately 7...

In this study, series of ring-substituted 2-styrylquinazolin-4(3H)-one and 4-chloro-2-styrylquinazoline derivatives were prepared. The syntheses of the discussed compounds are presented. The compounds were analyzed by RP-HPLC to determine lipophilicity. They were tested for their inhibitory activity on photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Prima...

The herbicides trifluralin (alpha,alpha,alpha-trifluoro-2,6-dinitro-N, N-dipropyl-p-toluidine) and diallate (S-[2,3-dichloroallyl] diisopropylthiocarbamate) inhibit electron transport, ATP synthesis, and cytochrome f reduction by isolated spinach (Spinacia oleracea L.) chloroplasts. Both compounds inhibit noncyclic electron transport from H(2)O to ferricyanide more than 90% in coupled chloropla...

In this study, a series of twenty-two 5-chloro-2-hydroxy-N-[2-(arylamino)-1-alkyl-2-oxoethyl]benzamides and ten 4-chloro-2-hydroxy-N-[2-(arylamino)-1-alkyl-2-oxoethyl]benzamides is described. The compounds were analyzed using RP-HPLC to determine lipophilicity. Primary in vitro screening of the synthesized compounds was performed against mycobacterial, bacterial and fungal strains. They were al...

Two series of thiosemicarbazone-based iron chelators (twenty-seven compounds) were designed and synthesized using a microwave-assisted approach. Quinoline and halogenated phenyl were selected as parent scaffolds on the basis of a similarity search. The lipophilicity of the synthesized compounds was measured using HPLC and then calculated. Primary in vitro screening of the synthesized compounds ...

The impact of supplemental UV-B (sUV-B) radiation and heavy metals: Cd (68 μmol.kg-1 soil) and Ni (68 μmol.kg-1 soil) singly and in combination was studied on photosynthetic and non-photosynthetic pigments, metabolites, enzyme activities, biomass accumulation and the net primary productivity of spinach (Spinacia oleracea L. var. All Green), a common leafy vegetable plant. Both the stresses indi...

The photosynthetic CO(2) fixation by spinach leaf (Spinacia oleracea L. var. Kyoho) protoplasts was inhibited by substituting an atmosphere of N(2) with one of either air (21% O(2)) or 100% O(2). The inhibitory effect of 100% O(2) was greater than that of air. The mode of inhibition by 100% O(2) and air was competitive with respect to CO(2); Ki(O(2)) value was 0.32 mM at pH 7 and 0.28 mM at pH ...