Abstract
Acceleration of membrane deterioration has been observed recently during storage of [gamma]-irradiated cauliflower (Brassica oleracea L., Botrytis group). In the present study, the activity of microsome-associated lipolytic enzymes was investigated in cauliflower florets exposed to 0 or 4 kilograys of [gamma] radiation and stored for 8 d at 13[deg]C. Radiolabeled breakdown products obtained from the metabolism of (16:0/18:2*)-phosphatidylcholine and (16:0/16:0)-phosphatidyl-[N-methyl-3H]choline by microsomal membranes indicated that phospholipase D (EC 3.1.4.4), phosphatidic acid phosphatase (EC 3.1.3.4), and lipolytic acyl hydrolase were associated with the membranes. The rate of phosphatidylcholine catabolism by the membranes increased slowly in control cauliflower during storage. [gamma] irradiation caused an immediate rise in phosphatidylcholine catabolism that remained higher than that of the controls during subsequent storage. Collectively, the data suggest that enhancement of membrane lipolytic activity results from free-radical-induced stress. Rapid increase of the membrane-associated phospholipase D activity may be a key event leading to accelerated membrane deterioration following [gamma] irradiation.
Full Text
The Full Text of this article is available as a PDF (639.9 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- BLIGH E. G., DYER W. J. A rapid method of total lipid extraction and purification. Can J Biochem Physiol. 1959 Aug;37(8):911–917. doi: 10.1139/o59-099. [DOI] [PubMed] [Google Scholar]
- Blée E., Schuber F. Efficient epoxidation of unsaturated fatty acids by a hydroperoxide-dependent oxygenase. J Biol Chem. 1990 Aug 5;265(22):12887–12894. [PubMed] [Google Scholar]
- Borochov A., Halevy A. H. Microviscosity of plasmalemmas in rose petals as affected by age and environmental factors. Plant Physiol. 1978 May;61(5):812–815. doi: 10.1104/pp.61.5.812. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Borochov A., Halevy A. H., Shinitzky M. Senescence and the Fluidity of Rose Petal Membranes : RELATIONSHIP TO PHOSPHOLIPID METABOLISM. Plant Physiol. 1982 Feb;69(2):296–299. doi: 10.1104/pp.69.2.296. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1006/abio.1976.9999. [DOI] [PubMed] [Google Scholar]
- Fobel M., Lynch D. V., Thompson J. E. Membrane deterioration in senescing carnation flowers : coordinated effects of phospholipid degradation and the action of membranous lipoxygenase. Plant Physiol. 1987 Sep;85(1):204–211. doi: 10.1104/pp.85.1.204. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hamberg M., Hamberg G. Hydroperoxide-dependent epoxidation of unsaturated fatty acids in the broad bean (Vicia faba L.). Arch Biochem Biophys. 1990 Dec;283(2):409–416. doi: 10.1016/0003-9861(90)90662-i. [DOI] [PubMed] [Google Scholar]
- Paliyath G., Thompson J. E. Calcium- and calmodulin-regulated breakdown of phospholipid by microsomal membranes from bean cotyledons. Plant Physiol. 1987 Jan;83(1):63–68. doi: 10.1104/pp.83.1.63. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thompson J. E., Mayak S., Shinitzky M., Halevy A. H. Acceleration of membrane senescence in cut carnation flowers by treatment with ethylene. Plant Physiol. 1982 Apr;69(4):859–863. doi: 10.1104/pp.69.4.859. [DOI] [PMC free article] [PubMed] [Google Scholar]