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CLA are predominantly found in milk, milk products, meat and meat products of ruminants. The distribution of CLA isomers in cheese and/or meat shows one major isomer C18:2 c9t11 with nearly 84% of total CLA. It is estimated that the daily intake of CLA using the German Nutrition Study is 0.35 g/d for women and 0.43 g/d for men.
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The effects of arachidonic acid and other fatty acids on mitochondrial Ca2+ transport were studied. Cis-unsaturated fatty acids generally strongly inhibited mitochondrial Ca2+ uptake, induced a net Ca2+ efflux, and thereby increased the extramitochondrial Ca2+ concentration, whereas trans-unsaturated fatty acids were ineffective. Saturated fatty acids exhibited slight activity at chain lengths from C(10) to C(14) only. The structure-activity relationship and the inability of some of the effective fatty acids such as palmitoleic and myristoleic acid to be metabolized to eicosanoids suggest that Ca2+ release was induced by the fatty acids themselves and resulted from changes in the mitochondrial membrane bilayer structure. There was a correlation between Ca2+-releasing potency and reduction of mitochondrial membrane potential, which is the main driving force for mitochondrial Ca2+ uptake. There were, however, considerable differences compared with the effects of lysophospholipids on the membrane potential. The mechanism of action of fatty acids may be that of a fluidizing effect on the hydrophobic core of the membrane, thereby modulating the activity of integral membrane proteins of the respiratory chain.
Our genetic make-up, shaped through millions of years of evolution, determines our nutritional and activity needs. Although the human genome has remained primarily unchanged since the agricultural revolution 10,000 years ago, our diet and lifestyle have become progressively more divergent from those of our ancient ancestors. Accumulating evidence suggests that this mismatch between our modern diet and lifestyle and our Paleolithic genome is playing a substantial role in the ongoing epidemics of obesity, hypertension, diabetes, and atherosclerotic cardiovascular disease. Until 500 generations ago, all humans consumed only wild and unprocessed food foraged and hunted from their environment. These circumstances provided a diet high in lean protein, polyunsaturated fats (especially omega-3 [omega-3] fatty acids), monounsaturated fats, fiber, vitamins, minerals, antioxidants, and other beneficial phytochemicals. Historical and anthropological studies show hunter-gatherers generally to be healthy, fit, and largely free of the degenerative cardiovascular diseases common in modern societies. This review outlines the essence of our hunter-gatherer genetic legacy and suggests practical steps to re-align our modern milieu with our ancient genome in an effort to improve cardiovascular health.
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Gas liquid chromatography and chromato-mass-spectrometry were used to study Queen bee jelly fatty acid composition. Trans-10-hydroxy-2-decenoic acid was determined as the mane component of Queen bee jelly fatty acid fraction. Mass-fragmentography GC-MS method was developed for determination of the trace trans-10-hydroxy-2-decenoic acid to authenticate Queen bee jelly in products and BAS.
By modifying the degree of hydrogenation of dietary fat, it is possible to modify the fatty acid composition and the biochemical activity of cellular tissues. The age can be another variable influencing these modifications. The effect of isocaloric diets containing oils with different degrees of hydrogenation: fish oil (FO, 0.3% TRANS), partially hydrogenated fish oil (PHFO, 29% TRANS), or highly hydrogenated fish oil (HHFO, 2.3% TRANS), in the fatty acid composition (CIS and TRANS isomers) of hepatic microsomes from young (70-day-old) and aged (18-month-old) rats, in the microsomal cytochrome P-450 (C-450) content, and in the aminopyrine N-demethylase (AND), aniline hydroxylase (AH), NADPH cytochrome P-450 reductase (NCR), UDP-glucuronyl transferase (UGT), and GSH-S transferase (GST) enzymatic activities were studied. Fatty acid composition and n-6/n-3 ratio of microsomal membranes was modified to a higher extent in young rats. C-450 content and AND activity were reduced when the degree of hydrogenation of dietary fat was increased in the young and the aged rats. AH activity was higher after the PHFO diet in the young rats only. NCR activity was reduced in the young animals when the hydrogenation of the fat was increased. However, in aged rats the enzyme exhibited a higher activity after the PHFO and HHFO diet. UGT and GST activities where not affected by the level of hydrogenation of the dietary fat in both the young and the aged rats. However, UGT activity was higher in the young rats, while GST activity was higher in the aged animals. We conclude that hydrogenation of dietary fat can modify the fatty acid composition of hepatic microsomes, young animals being more sensitive to these changes than aged animals. These effects were also reflected in the amount and/or the activity of some molecular components of the hepatic microsomal mixed-function oxidase enzyme system. Microsomal TRANS fatty acid composition is not affecting the activity of the enzymes, the age of the animals being the most important factor.
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Ethyl esters (FAEE) and trideuterium-labeled methyl esters (d3-FAME) of fatty acids were prepared and investigated regarding their suitability as internal standards (IS) for the determination of fatty acids as methyl esters (FAME). On CP-Sil 88, ethyl esters of odd-numbered fatty acids eluted approximately 0.5 min after the respective FAME, and only coelutions with minor FAME were observed. Depending on the problem, one or even many FAEE can be added as IS for the quantification of FAME by both GC-FID and GC-MS. By contrast, d3-FAME coeluted with FAME on the polar GC column, and the use of the former as IS requires application of GC-MS. In the SIM mode, m/z 77 and 90 are suggested for d3-methyl esters of saturated fatty acids, whereas m/z 88 and 101 are recommended for ethyl esters of saturated fatty acids. These m/z values give either no or very low response for FAME and can thus be used for the analysis of FAME in food by GC-MS in the SIM mode. Fatty acids in sunflower oil and mozzarella cheese were quantified using five saturated FAEE as IS. Gravimetric studies showed that the transesterification procedure could be carried out without of loss of fatty acids. GC-EI/MS full scan analysis was suitable for the quantitative determination of all unsaturated fatty acids in both food samples, whereas GC-EI/MS in the SIM mode was particularly valuable for quantifying minor fatty acids. The novel GC-EI/MS/SIM method using fatty acid ethyl esters as internal standards can be used to quantify individual fatty acids only, that is, without determination of all fatty acids (the common 100% method), although this is present. This was demonstrated by the exclusive quantification of selected fatty acids including methyl-branched fatty acids, erucic acid (18:1n-9trans), and polyunsaturated fatty acids in cod liver oil and goat's milk fat.
Cellular energy metabolism is largely sustained by mitochondrial beta-oxidation of saturated and unsaturated fatty acids. To study the role of unsaturated fatty acids in cellular lipid and energy metabolism we generated a null allelic mouse, deficient in 3,2-trans-enoyl-CoA isomerase (ECI) (eci(-/-) mouse). ECI is the link in mitochondrial beta-oxidation of unsaturated and saturated fatty acids and essential for the complete degradation and for maximal energy yield. Mitochondrial beta-oxidation of unsaturated fatty acids is interrupted in eci(-/-)mice at the level of their respective 3-cis- or 3-trans-enoyl-CoA intermediates. Fasting eci(-/-) mice accumulate unsaturated fatty acyl groups in ester lipids and deposit large amounts of triglycerides in hepatocytes (steatosis). Gene expression studies revealed the induction of peroxisome proliferator-activated receptor activation in eci(-/-) mice together with peroxisomal beta- and microsomal omega-oxidation enzymes. Combined peroxisomal beta- and microsomal omega-oxidation of the 3-enoyl-CoA intermediates leads to a specific pattern of medium chain unsaturated dicarboxylic acids excreted in the urine in high concentration (dicarboxylic aciduria). The urinary dicarboxylate pattern is a reliable diagnostic marker of the ECI genetic defect. The eci(-/-) mouse might be a model of a yet undefined inborn mitochondrial beta-oxidation disorder lacking the enzyme link that channels the intermediates of unsaturated fatty acids into the beta-oxidation spiral of saturated fatty acids.
The purpose of this study was to examine the effect of 0-50 micromol/L trans-10, cis-12 conjugated linoleic acid (CLA) and cis-9, trans-11 CLA isomers on lipid and glucose metabolism in cultures of differentiating 3T3-L1 preadipocytes. Specifically, we investigated the effects of 6 d of CLA treatment on the following: 1) (14)C-glucose and (14)C-oleic acid incorporation and esterification into lipid; 2) (14)C-glucose and (14)C-fatty acid oxidation; and 3) basal and isoproterenol-stimulated lipolysis. Trans-10, cis-12 CLA supplementation (25 and 50 micromol/L) increased both (14)C-glucose and (14)C-oleic acid incorporation into the cellular lipid fraction, which was primarily triglyceride (TG), compared with bovine serum albumin (BSA) controls. Although glucose oxidation ((14)C-glucose to (14)C-CO(2)) was unaffected by CLA supplementation, oleic acid oxidation ((14)C-oleic acid to (14)C-CO(2)) was increased by approximately 55% in the presence of 50 micromol/L trans-10, cis-12 CLA compared with BSA controls. In contrast, 50 micromol/L linoleic acid (LA) and cis-9, trans-11 CLA-treated cultures had approximately 50% lower CO(2) production from (14)C-oleic acid compared with control cultures after 6 d of fatty acid exposure. Finally, 50 micromol/L trans-10, cis-12 CLA modestly increased basal, but not isoproterenol-stimulated lipolysis compared with control cultures. Thus, the TG-lowering actions of trans-10, cis-12 CLA in cultures of 3T3-L1 preadipocytes may be via increased fatty acid oxidation, which exceeded its stimulatory effects on glucose and oleic acid incorporation into lipid.
[14C]Linoleic acid was incubated with phenobarbital-induced rat liver microsomes and formation of cis-trans-conjugated hydroxy fatty acids was investigated. 13-Hydroxy-9Z,11E-octadecadienoic acid (13-HODE), 9-hydroxy-10E,12Z-octadecadienoic acid (9-HODE), and three novel metabolites were identified, viz. 11-hydroxy-9Z,12Z-octadecadienoic acid (11-HODE), 8-HODE, and 14-HODE. 11-HODE (59% R), the main product, was unstable and converted to 9(R, S)-HODE and 13(R, S)-HODE in acidic media. All metabolites contained oxygen from O2. Experiments under oxygen-18 gas showed that 13-HODE and 9-HODE contained equal or less amounts of oxygen-18 than the other metabolites. In the former case, 9-HODE and 13-HODE were formed with stereo-selectivity (80-82% R). [11S-2H]Linoleic acid was metabolized to 13R-HODE with loss of deuterium (24% 2H) and to 9R-HODE with deuterium retention (95% 2H), while [11R-2H]linoleic acid was metabolized to 13R-HODE that largely retained the label (71% 2H) and to 9R-HODE that lost most of the label (22% 2H). These data indicated that P450 catalyzed abstraction of the pro-R hydrogen at C11, double bond migration and suprafacial oxygen insertion at C9 to give 9R-HODE, while abstraction of the pro-S hydrogen at C11, followed by double bond migration and oxygen insertion, yielded 13R-HODE. Hepatic microsomes of the cynomolgus monkey metabolized 18:2n-6 as above and 20:4n-6 to 13-hydroxyeicosatetraenoic acid, likely formed in analogy with 11-HODE. In summary, one mechanism in the biosynthesis of cis-trans-conjugated hydroxy fatty acids by P450 involves suprafacial hydrogen abstraction and oxygen insertion. In addition, hydrolysis of the unstable bis-allylic hydroxy metabolites may contribute to the formation of conjugated hydroxy fatty acids.
The effects of replacing corn oil with corn oil margarine in stick form on endogenous cholesterol synthesis and susceptibility of low-density lipoprotein (LDL) to oxidation were assessed in 14 middle-aged and elderly men and women aged 63 +/- 12 years (mean +/- SD) with moderate hypercholesterolemia (mean LDL-cholesterol [LDL-C], 4.24 +/- 0.59 mmol/L at the time of recruitment). Subjects consumed each of two diets for 32-day periods, one enriched in corn oil, which contained 30% of energy as fat (7% saturated fatty acid [SFA], 9% monounsaturated fatty acid [MUFA] [0.4% 18:1n9 trans], and 11% polyunsaturated fatty acid [PUFA]) and 85 mg cholesterol/4.2 MJ, and one enriched in stick corn oil margarine, which contained 30% fat (8% SFA, 12% MUFA [4.2% 18:1n9trans], and 8% PUFA) and 77 mg cholesterol/4.2 MJ. Both diets were isocaloric and supplied by a metabolic research kitchen. Mean total cholesterol levels were lowest (P = .039) when subjects consumed the corn oil-enriched diet (5.01 +/- 0.51 mmol/L) as compared with the margarine-enriched diet (5.30 +/- 0.58 mmol/L). LDL-C levels were 3.24 +/- 0.51 and 3.50 +/- 0.54 mmol/L when subjects consumed corn oil-and margarine-enriched diets, respectively (P = .058). There were no significant differences in high-density lipoprotein cholesterol (HDL-C) or triglyceride concentrations between the two experimental periods. Consumption of the margarine-enriched diet versus the corn oil-enriched diet tended to result in lower cholesterol fractional synthetic rates ([C-FSRs] 0.0466 +/- 0.0175 and 0.0668 +/- 0.0298, respectively, P = .080) and cholesterol absolute synthetic rates ([C-ASRs] 1.1761 +/- 0.5375 and 1.6954 +/- 0.8685, respectively, P = .092); however, differences did not reach statistical significance. Consumption of the margarine-enriched diet versus the corn oil-enriched diet resulted in a significantly higher concentration of alpha-tocopherol in both plasma and LDL(P = .004 and P = .011, respectively). LDL particle size tended to be smaller after subjects consumed the margarine-enriched diet versus the corn oil-enriched diet (P = .103). Susceptibility of LDL to oxidation was similar after consumption of the corn oil- and margarine-enriched diets. These data suggest that an increased rate of endogenous cholesterol synthesis did not contribute to the higher plasma cholesterol concentrations during the period when subjects consumed the margarine-enriched diet. Therefore, the increase in cholesterol concentration resulting from margarine consumption was likely attributable, at least in part, to a decreased catabolic rate of cholesterol. Additionally, susceptibility of LDL to in vitro oxidation was not altered by consumption of hydrogenated fat.
Ester-linked phospholipid fatty acid (PLFA) profiles of a Pseudomonas aureofaciens strain and an Arthrobacter protophormiae strain, each isolated from a subsurface sediment, were quantified in a starvation experiment in a silica sand porous medium under moist and dry conditions. Washed cells were added to sand microcosms and maintained under saturated conditions or subjected to desiccation by slow drying over a period of 16 days to final water potentials of approximately - 7.5 MPa for the P. aureofaciens and - 15 MPa for the A. protophormiae. In a third treatment, cells were added to saturated microcosms along with organic nutrients and maintained under saturated conditions. The numbers of culturable cells of both bacterial strains declined to below detection level within 16 days in both the moist and dried nutrient-deprived conditions, while direct counts and total PLFAs remained relatively constant. Both strains of bacteria maintained culturability in the nutrient-amended microcosms. The dried P. aureofaciens cells showed changes in PLFA profiles that are typically associated with stressed gram-negative cells, i.e., increased ratios of saturated to unsaturated fatty acids, increased ratios of trans- to cis-monoenoic fatty acids, and increased ratios of cyclopropyl fatty acids to their monoenoic precursors. P. aureofaciens starved under moist conditions showed few changes in PLFA profiles during the 16-day incubation, whereas cells incubated in the presence of nutrients showed decreases in the ratios of both saturated fatty acids to unsaturated fatty acids and cyclopropyl fatty acids to their monoenoic precursors. The PLFA profiles of A. protophormiae changed very little in response to either nutrient deprivation or desiccation. Diglyceride fatty acids, which have been proposed to be indicators of dead or lysed cells, remained relatively constant throughout the experiment. Only the A. protophormiae desiccated for 16 days showed an increase in the ratio of diglyceride fatty acids to PLFAs. The results of this laboratory experiment can be useful for interpreting PLFA profiles of subsurface communities of microorganisms for the purpose of determining their physiological status.
Although starvation survival has been characterized for many bacteria, few subsurface bacteria have been tested, and few if any have been tested in natural subsurface porous media. We hypothesized that subsurface bacteria may be uniquely adapted for long-term survival in situ. We further hypothesized that subsurface conditions (sediment type and moisture content) would influence microbial survival. We compared starvation survival capabilities of surface and subsurface strains of Pseudomonas fluorescens and a novel Arthrobacter sp. in microcosms composed of natural sediments. Bacteria were incubated for up to 64 weeks under saturated and unsaturated conditions in sterilized microcosms containing either a silty sand paleosol (buried soil) or a sandy silt nonpaleosol sediment. Direct counts, plate counts, and cell sizes were measured. Membrane phospholipid fatty acid (PLFA) profiles were quantified to determine temporal patterns of PLFA stress signatures and differences in PLFAs among strains and treatments. The Arthrobacter strains survived better than the P. fluorescens strains; however, differences in survival between surface and subsurface strains of each genus were not significant. Bacteria survived better in the paleosol than in the nonpaleosol and survived better under saturated conditions than under unsaturated conditions. Cell volumes of all strains decreased; however, sediment type and moisture did not influence rates of miniaturization. Both P. fluorescens strains showed PLFA stress signatures typical for gram-negative bacteria: increased ratios of saturated to unsaturated fatty acids, increased ratios of trans- to cis-monoenoic fatty acids, and increased ratios of cyclopropyl to monoenoic precursor fatty acids. The Arthrobacter strains showed few changes in PLFAs. Environmental conditions strongly influenced PLFA profiles.
The hydrocarbon-chain orientational order parameters of membranes of Acholeplasma laidlawii B enriched with straight-chain saturated, methyl iso-branched, methyl anteiso-branched, or trans-unsaturated fatty acids have been determined via fluorine-19 nuclear magnetic resonance spectroscopy (19F NMR). A theoretical description of the 19F NMR spectral line shape is presented that permits the determination of the orientational order parameters associated with specifically monofluorinated palmitic acid probes biosynthetically incorporated into membrane glycerolipids. Membrane orientational order profiles determined by 19F NMR in the case of straight-chain saturated fatty acid enrichment were qualitatively similar to profiles obtained by 2H NMR. The methyl iso-branch and methyl anteiso-branch structural substituents induced a local ordering while the trans double bond substituent induced a local disordering evident from alterations to the character of the orientational order profile. These various effects could be understood in terms of an altered probability of the occurrence of rotational isomerization in the presence of particular substituents. At 37 degrees C the overall orientational order decreased in the progression eta-acyl greater than iso branched greater than anteiso branched greater than or equal to trans double bonded. The relative overall order was then a direct function of the relative proximity of the membrane lipids to their respective gel to liquid-crystalline phase transitions. When observed at Tm + 15 degrees C, where the different species of fatty acids could be considered to be in a comparable thermodynamic state, the overall order decreased in the progression anteiso branch greater than trans double bond greater than iso branch greater than eta-acyl.(ABSTRACT TRUNCATED AT 250 WORDS)
Dietary cis-9, trans-11-conjugated linoleic acid (CLA) is generally thought to be beneficial for human health. Fish oil added to ruminant diets increases the CLA concentration of milk and meat, an increase thought to arise from alterations in ruminal biohydrogenation of unsaturated fatty acids. To investigate the mechanism for this effect, in vitro incubations were carried out with ruminal digesta and the main biohydrogenating ruminal bacterium, Butyrivibrio fibrisolvens. Linoleic acid (LA) or alpha-linolenic acid (LNA) was incubated (1.67 g/l) with strained ruminal digesta from sheep receiving a 50:50 grass hay-concentrate ration. Adding fish oil (up to 4.17 g/l) tended to decrease the initial rate of LA (P=0.025) and LNA (P=0.137) disappearance, decreased (P<0.05) the transient accumulation of conjugated isomers of both fatty acids, and increased (P<0.05) the accumulation of trans-11-18:1. Concentrations of EPA (20:5n-3) or DHA (22:6n-3), the major fatty acids in fish oil, were low (100 mg/l or less) after incubation of fish oil with ruminal digesta. Addition of EPA or DHA (50 mg/l) to pure cultures inhibited the growth and isomerase activity of B. fibrisolvens, while fish oil had no effect. In contrast, similar concentrations of EPA and DHA had no effect on biohydrogenation of LA by mixed digesta, while the addition of LA prevented metabolism of EPA and DHA. Neither EPA nor DHA was metabolised by B. fibrisolvens in pure culture. Thus, fish oil inhibits ruminal biohydrogenation by a mechanism which can be interpreted partly, but not entirely, in terms of its effects on B. fibrisolvens.
The availability of an excellent separation method for fatty acid methyl esters, including separation of cis and trans isomers and of isomers that differ only in the position of double bonds, has become more and more important. The present glass capillary chromatography system combines high separation power with high precision and easy handling. Moreover, the system is completely automated and therefore provides a time saving method. As compared to a conventional packed column, the glass capillary column provides about one hundred fold more theoretical plates (227,000), as well as narrower peaks, thus giving rise to less error when integrating with electronic integrators. The reproducibility for relative retention time is better with the capillary column (0.26%) and reproducibility of the weight percent values is at least similar to that of the packed column (1.53%). When handling only small sample amounts the capillary provides better values because of its low capacity. This powerful system should open up new possibilities in the field of fatty acid investigation.