Phospholipids fatty acid changes

Fig. 2. Hepatocyte phospholipid fatty acid changes in rats fed an eicosapentaenoic acid (EPAVy-linolenic acid (CLA) diet. Results are means SEM, n = 7, and are expressed as a percentage of control.

L. Zelles, A. Palojarvi, E. Kandeler, M. VonLut/.ow, K. Winter, Q. Y. Bai. Changes in. soil mierobial properties and phospholipid fatty acid fractions after chloroform fumigation. Soil Biol. Biochem. 29 1325 (1997). 

Pennanen T (2001) Microbial communities in boreal coniferous forest humus exposed to heavy metals and changes in soil pH a summary of the use of phospholipids fatty acids, Biolog and H-thymidine incorporation methods in field studies. Geoderma 100 91-126... 

Application of data obtained from simple clean reaction systems in biological or chemical studies of heme catalysis also has its problems. Chemical model systems use chelators, model hemes, and substrate structures that are quite different from those existing in foods. Reaction sequences change with heme, substrate, solvent, and reaction conditions. Intermediates are often difficult to detect (141), and derivations of mechanisms by measuring products and product distributions downstream can lead to erroneous or incomplete conclusions. It is no surprise, then, that there remains considerable controversy over heme catalysis mechanisms. Furthermore, mechanisms determined in these defined model systems with reaction times of seconds to minutes may or may not be relevant to lipid oxidation being measured in the complex matrices of foods stored for days or weeks under conditions where phospholipids, fatty acid composition, heme state, and postmortem chemistry complicate the oxidation once it is started (142). Hence, the mechanisms outlined below should be viewed as guides rather than absolutes. More research should be focused on determining, by kinetic and product analyses, which reactions actually occur and are of practical importance in specific food systems. 

Rioux EM, Innis SM, Dyer R, MacKinnon M. Diet-induced changes in liver and bile but not brain fatty acids can be predicted from differences in plasma phospholipid fatty acids in formula- and milk-fed piglets. J Nutr 1997 127(2) 370-377. 

Fig. 1. The time-course of mean fatty acid changes in plasma phospholipids after the feeding of fish oil. Note that reciprocal changes ofthe two major n-3 (EPA andDH A) and the major n-6 (18 2) polyunsaturated fatty acids occurred as n-3 fatty acids increased and n-6 fatty acids decreased. The concentrations of these fatty acids in the plasma phospholipids of monkeys fed the control soybean oil and safflower oil diet from our previous study (Neuringer et al, 1986) are given for comparison. Expressed as percentage of total fatty acids, DHA in control monkeys was 1.1 0.7% EPA 0.2 0.1% 18 2n-6, 39.6 2.3%. In deficient monkeys, DHA was 0% 18 2n-6 was 36.7 0.7%.

Dramatic changes in the fatty acids of the frontal cortex were detected within 1 wk after the fish-oil diet was given as demonstrated in the individual data in the frontal lobe biopsy specimens from five juvenile monkeys. All four major phospholipid classes of the brain underwent extensive remodeling of their constituent fatty acids. The data in Fig. 3 is for the fatty acids of phosphatidylethanolamine from each of the five experimental monkeys. By 12-28 wk, the total n-3 fatty acids increased from 4% to 36%of total fatty acids (Connor et al., 1990b). The major increase was in DHA, from 4% to 29%, whereas EPA and 22 5n-3, another n-3 fatty acid found in fish oil, each increased from 0% to almost 3%. To be emphasized, as will be discussed later, is the apparent conversion of EPA to DHA in the brain. The total n-6 fatty acids reciprocally decreased from 44% to 16% of the total fatty acids, with the major reduction occurring in 22 5n-6, from 18% to 2%, and 22 4n-6, from 12% to 4%. There was also a moderate decrease of arachidonic acid from 12.8% to 8.9% of total fatty acids. Again, a major remodeling of the phospholipid fatty acids from n-6 to n-3 fatty acids was evident. 

Before 1940 it was generally considered that phosphohpids, once laid down in the nervous system of mammals during growth and development, were comparatively static entities. However, later studies using (32p)oithophosphate showed that brain phospholipids as a whole are metabolically active in vivo (Ansell and Dohmen, 1957, Crokin and Sun, 1978). In the present study, by following the changes in phospholipid fatty acid composition, we have demonstrated that an n-3 fatty acid-enriched diet can rapidly reverse a severe n-3 fatty acid deficiency in the brains of primates. The phospholipid fatty acids of the cerebral cortex of juvenile monkeys are in adynamic state and are subject to continuous turnover under certain defined conditions. 

Delion S, Chalon S, Guilloteau D, Lejeune B, Besnard JC, Durand G. Age-related changes in phospholipid fatty acid composition and monoaminergic neurotransmission in the hippocampus of rats fed a balanced or an n-3 polyunsaturated fatty acid deficient diet. J Lipid Res 1997 38 680-689. 

Zelles, L., Palojarvi, A., Kandeler, E., von LQtzow, M., Winter, K. and Bai, Q.Y. (1997) Changes in soil microbial properties and phospholipid fatty acid fractions after chloroform fumigation. Soil Biology and Biochemistry 29, 1325-1336. 

The changes in heart mitochondrial phospholipids when rats are fed peanut oil, LEAR oil, or HEAR oils are shown in Table XIX. The pattern of fatty acids in each of the three phospholipids is very similar to that observed for the total cardiac phospholipids shown in Tables XIV to XVI as pointed out by Blomstrand and Svensson (1974) who found no significant difference in the relative distribution of phospholipids between mitochondrial and total heart phospholipids. Some of the phospholipid fatty acid patterns that have been reported are at variance with the generally accepted values. This could be the result of insufficient purification of mitochondrial lipids or improper procedures of lipid extraction (Rouser et ai, 1968 Kuksis, 1978). 

Where the fat in a meat or meat product sample is to be characterized in terms of the fatty acid profile, extraction of the fat with chloroform/methanol is required. This solvent mixture, while it may not give complete fat extraction, is used to ensure no chemical change to the lipids and the extraction of phospholipids. Fatty acid analysis of the extracted fat is undertaken by formation of volatile methyl esters of the fatty acids (ISO 5509 2000) and determination by gas chromatography (ISO 5508 1990). 

Bottcher, C. J. F., and C. M. van Gent Changes in the composition of phospholipids and of phospholipid fatty acids associated with atherosclerosis in the human aortic wall. J. Atheroscler. Res. 1, 36 (1961). 

The observations on platelet phospholipids and phospholipid fatty acids in the studies reported above give clear indication that these changes were nutritionally induced. Even the changes that were related to age could be interpreted to have occurred as a consequence of long-term nutritional adaptation. 

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