Dominant Polar Lipids Research Articles

Lipids and lipid antioxidant systems in developing eggs of salmon (Salmo salar)

AbstractLipid class and fatty acid analyses were carried out on developing salmon eggs at four clearly defined pre‐feeding stages, namely, fertilization, eyed egg stage (50 days), hatching (yolk sac fry, 98 days) and swim up fry (138 days).Measurements of components of the system considered to be involved in defense of cells against lipid peroxidation (glutathione peroxidase, EC 1.11.1.9, glutathione S‐transferase, EC 2.5.1.18, reduced glutathione [GSH], α‐tocopherol and ascorbic acid) were made at the same time. Levels of triacylglycerol decreased markedly during development, but there were few changes in fatty acid composition, indicating a non‐selective utilization of fatty acids. Phosphatidylcholine was the dominant polar lipid (>94% by weight) in fertilized eggs. It was used preferentially during development so that in swim up fry the ratio phosphatidylcholine: phosphatidylethanolamine approached that found in fish muscle. Amounts of docosahexaenoic acid and arachidonic acid in polar lipids were significantly greater (p<0.01) in swim up fry than in fertilized eggs.Activities of the two enzymes were very low in the fertilized egg and remained low until hatching, when there was a concerted increase in their activity and in the concentration of GSH. Egg tocopherol concentrations decreased significantly during development, but whole body concentrations in swim up fry were not dissimilar from those in normal juvenile fish. Ascorbic acid, on the other hand, declined to very low levels in swim up fry; the restoration of this vitamin during first feeding seems vital to the well being of the fish.

The composition of the lipids of Gromphadorhina portentosa L. (blattidae)

1. 1. The differences between the content and composition of the lipids extracted from mature male and female specimens of Gromphadorhina portentosa (L.) were analyzed. 2. 2. The females contained almost twice as much lipid as the males principally because of their greater content of neutral lipid material, mainly the triglycerides. 3. 3. Phosphatidylcholine and phosphatidylethanolamine were the dominant polar lipid classes in both the male and female and the distribution of the phospholipid classes was similar in both sexes. 4. 4. Palmitic and oleic acids accounted for more than 70 per cent of the total fatty acids in both genders. 5. 5. The males generally possessed a higher content of linoleic acid than the females. 6. 6. The observed differences are compared with lipid compositions of other species.