Showing papers on "Docosahexaenoic acid published in 1973"

Membrane Fatty Acids Associated with the Electrical Response in Visual Excitation

Abstract: The fatty acid composition of rat photoreceptor membranes was altered by dietary manipulation. A functional alteration was also observed in the component of the electroretinogram which is generated by the photoreceptors. A membrane fatty acid, docosahexaenoic acid, appears to be involved in the transduction process of visual excitation.

The phospholipid-bound fatty acids and aldehydes of mammalian spermatozoa

Abstract: 1. 1. The phospholipid-bound fatty acids of ram, bull, boar, rabbit and human spermatozoa contained high levels of polyunsaturated fatty acids. Values ranged from 70 per cent by weight of the total fatty acid fraction in the boar to approximately 40 per cent in both human and rabbit. 2. 2. Docosahexaenoic acid (22:6) was quantitatively the most important fatty acid found in all species except the rabbit. 3. 3. The major saturated fatty acid found in mammalian spermatozoa was palmitic acid. 4. 4. The predominant fatty aldehyde was palmitaldehyde (16:0) and values ranged from 91·2 per cent in ram to 51·1 per cent in human spermatozoa.

Metabolism of fatty acids by ovine spermatozoa

Abstract: The incorporation of 14C-labelled myristic, palmitic, stearic, oleic and linoleic acids in vitro into the lipids of ovine spermatozoa was followed at time intervals from 2 min to 2 hr. Diglycerides readily incorporated fatty acids; 1,2and 1,3-diglyceride fractions showed preferential specificities for palmitic and myristic acids, respectively, but stearic acid was poorly metabolized by both components. The lower incorporation of acids into total phospholipids reflected the relative metabolic stability of the major phospholipid fractions in ovine spermatozoa, but the minor phospholipids, particularly phosphatidylinositol, showed comparatively high metabolic activity. Compositional analyses showed that myristic acid was the major component of diglycerides, whereas docosahexaenoic acid was the principal fatty acid of the major phospholipid classes. These findings have been compared with previous work on fatty acid metabolism in bovine spermatozoa.

Incorporation of docosahexaenoic fatty acid into the lipids of a cestode of marine elasmobranchs.

Abstract: Callibothrium verticillatum, a cestode from the spiral intestine of the dogfish, Mustelus canis, incorporated a characteristic polyunsaturated fatty acid of marine organisms (22:6 03) without conversion or degradation. The tapeworm was incubated in vitro with [14C] 22:6 w3. Its labeled lipids were fractionated and their radioactivities assayed by column and thin-layer radiochromatography nlethods. Triglyceride (50% of dpm collected) and unesterified fatty acids (28%) were the most radioactive fractions. Sterol ester, wax ester, diacylglyceryl ether, diglyceride, monoglyceride, cardiolipin, phosphatidylethanolamine, phosphatidylserine, and phosphatidylcholine also were radioactive. 22:6 ca3 and the other fatty acids of the tapeworm were collected by preparative gas-liquid radiochromatography from the total fatty acids, hydrogenated total fatty acids, triglyceride fatty acids, and unesterified fatty acids. Only 22:6 w3 was radioactive. Lipids were 25% of the dry weight of C. verticillatum. The major lipids were triglyceride (54 wt% of total) and phosphatidylcholine (25%). The polyunsaturated fatty acids of the neutral lipids were mostly eicosenoic (20:5 w3 was 25% of total), and of the polar lipids were docosenoic (22:6 w3 was 30%). The fatty acid composition of the tapeworm, the contents of the spiral intestine, and the fluids and tissues of the dogfish were strikingly similar. It is concluded that polyunsaturates may be passed intact from one trophic level to another in marine food chains, and that tapeworms can be used to monitor lipids in the food chains in which the hosts participate. Polyunsaturated C20 and C22 fatty acids are characteristic components of the storage and membrane lipids of most marine organisms; for example, planktonic unicellular algae (except blue-greens and the Chlorophyceae) (Kates and Volcani, 1966; Ackman et al., 1968; Chuecas and Riley, 1969; Holz, 1969; Lee and Loeblich, 1971), benthic multicellular algae (except Chlorophyceae) (Wagner and Pohl, 1965; Chuecas and Riley, 1966; Pohl et al., 1968; Radunz, 1968; Jamieson and Reid, 1972), protozoa (Uronema sp., Labyrinthula sp.) (Harrington, G. W., and Holz, G. G., Jr., unpublished), phycomycete fungi (Ellenbogen et al., 1969), invertebrates (Ackman and Eaton, 1966, 1967; Ackman et al., 1970; Culkin and Morris, 1970a, b; Lee et al., 1971), and vertebrates (Kayama et al., 1963a, b; Ackman, 1967; Ackman et al., 1971; Malins and Wekell, 1970). They are synthesized de novo by the photosynthetic planktonic and benthic algae. Marine animals incorporate them intact from their diet, and also biosynthesize them by elongating and desaturating C18 acids such as 18:2 o6, 18:3 w3, and 18:4 o3. Some invertebrates may obtain C20 and C22 polyunsaturates and/or their precursors from seawater directly Received for publication 20 March 1973. through their body surfaces (Testerman, 1972). Heterotrophic algae, protozoa, and the fungi may supply themselves with the C20 and C22 polyunsaturates by de novo synthesis, by direct incorporation from the environment, and by elongation and desaturation of the Cis fatty acids. The most typical marine polyunsaturates are o)3 eicosapentaenoic and docosahexaenoic acids with methylene-interrupted double bonds of the cis configuration; i.e., all-cis, 5,8,11,14, 17-20:5 and 4,7,10,13,16,19-22:6 (Ackman, 1964; Hinchcliffe and Riley, 1971). The cestodes of sharks contain these fatty acids (Buteau et al., 1969, 1971) and it has been assumed that they acquire them from their immediate environment, the contents of the spiral intestine. We have tested the possibility of direct incorporation, by exposing a tetraphyllidean of sharks to [14C] 22:6 o3 and then performing a radiochemical analysis of the lipids of the tapeworm to determine the distribution of the polyunsaturate. Cestodes were chosen as particularly favorable material for an experiment on direct incorporation of 22:6 oj3 since they neither oxidize nor biosynthesize fatty acids de novo (Meyer et al., 1966).

Egg yolk lipids and maternal diet in the nutrition of turkey embryo.

Abstract: Turkey hens were fed diets containing no added fat nor diets supplemented with soybean oil or neatsfoot oil. The composition of neutral and polar lipid fatty acids present in the unincubated turkey egg yolk was compared with that of those present in the yolk sac of the developing turkey embryo at different stages of development. Comparisons were made of the fatty acid fractions in the entire embryo homogenates, except liver and heart, which were analyzed separately. Changes in the relative amounts of the fatty acids are reported as affected by age of the embryo and by dietary lipids. The fatty acids from both the neutral and polar lipids which were utilized to the greatest extent for embryonic development were palmitoleic, oleic, linoleic, and linolenic, regardless of the dietary supplements. Arachidonic, tetracosenoic, and docosahexaenoic acids also were metabolized by the embryo. Saturated fatty acids, used by the embryo as development progressed, were palmitic, stearic, and arachidic acids. Analyses of the liver fatty acids showed that the C16∶0 C16∶1, C18∶0, C18∶1, and C20∶4 acids in the neutral and polar lipids decreased with embryonic development and varied with the type of diet. The heart contained low levels of myristic, palmitic, stearic, arachidic, and arachidonic acids in the neutral lipids and palmitoleic and oleic acids in the polar lipids.