linoleic-acid and hexacosanoic-acid

Spongy tissue is a physiological disorder in Alphonso mango caused by the inception of germination-associated events during fruit maturation on the tree, rendering the fruit inedible. Inter-fruit competition during active fruit growth is a major contributing factor for the disorder which leads to reduced fat content in spongy tissue affected fruits. This study was, therefore, carried out to determine the possible association between seed fats and ST formation. The study of the fat content during fruit growth showed that it increased gradually from 40 percent fruit maturity. At 70 percent maturity, however, there was a sudden increase of fat content of whole fruit, leading to acute competition and resulting in differential allocation of resources among developing fruits. As a result, the seed in spongy-tissue-affected mature ripe fruit showed a marked drop in the levels of fats and the two very long chain fatty acids (VLCFAs), tetracosanoic acid and hexacosanoic acid together with an increase of linolenic acid and a fall in oleic acid contents, which are known to be key determinants for the initiation of pre-germination events in seed. Subsequently, a rise in the level of cytokinin and gibberellins in ST seed associated with a fall in abscisic acid level clearly signalled the onset of germination. Concurrently, a significant reduction in the ratio of linolenic acid/linoleic acid in pulp led to the loss of membrane integrity, cell death and the eventual formation of spongy tissue. Based on the above, it is concluded that a significant reduction in the biosynthesis of VLCFAs in seeds during fruit growth might trigger pre-germination events followed by a cascade of biochemical changes in the pulp, leading to lipid peroxidation and membrane injury in pulp culminating in ST development. Thus, this study presents crucial experimental evidence to highlight the critical role played by VLCFAs in inducing ST formation in Alphonso mango during the pre-harvest phase of fruit growth.

Topics: Abscisic Acid; alpha-Linolenic Acid; Cytokinins; Fatty Acids; Fruit; Gas Chromatography-Mass Spectrometry; Germination; Gibberellins; Linoleic Acid; Mangifera; Oleic Acid; Plant Diseases; Plant Growth Regulators; Superoxides

Blood cell and plasma lipid classes and their fatty acids were analyzed in a child with X-linked adrenoleukodystrophy. The increase in saturated fatty acids with very long chains typical of this disease occurred almost exclusively in sphingomyelin. In this lipid, the proportion of lignoceric (24:0) and hexacosanoic (26:0) acids increased while that of 18:0, 20:0, and 24:1 decreased. In the rest of the lipid classes, but especially in cholesteryl esters and triacylglycerols, the proportion of linoleate (18:2) decreased while that of oleate (18:1) increased. In glycerophospholipids, polyunsaturated fatty acids such as 20:4n-6, 22:5n-6, and 22:6n-3 were reduced while their immediate precursors, 20:3n-6, 22:4n-6, and 22:5n-3, respectively, were relatively increased, suggesting a defect in fatty acid desaturation mechanisms. Although less pronounced, a similar trend of changes was seen in the patient's mother; in both, all alterations were more marked in serum than in blood cells.

Topics: Adrenoleukodystrophy; Child; Fatty Acids; Fatty Acids, Unsaturated; Genetic Linkage; Humans; Linoleic Acid; Linoleic Acids; Male; Oleic Acid; Oleic Acids; Phospholipids; Sphingomyelins; X Chromosome