Average Fatty Acid Chain Length Research Articles

The Effect of Combined Exposure of Fusarium Mycotoxins on Lipid Peroxidation, Antioxidant Defense, Fatty Acid Profile, and Histopathology in Laying Hens' Liver.

Fumonisin B1, T-2 toxin, and deoxynivalenol are frequently detected in feed materials. The mycotoxins induce free radical formation and, thereby, lipid peroxidation. The effects of mycotoxin exposure at the EU recommended limit (T-2/HT-2 toxin: 0.25 mg/kg; DON = 3AcDON/15-AScDON: 5 mg/kg; fumonisin B1: 20 mg/kg) and double dose (T-2/HT-2 toxin: 0.5 mg/kg, DON/3-AcDON/15-AcDON: 10 mg, and FB1: 40 mg/kg feed) were investigated during short-term (3 days) per os exposure in the liver of laying hens. On day 1 higher while on day 3 lower MDA concentrations were found in the low-dose group compared to the control. Fatty acid composition also changed: the proportion of monounsaturated fatty acids increased (p < 0.05) and the proportion of polyunsaturated fatty acids decreased by day 3. These alterations resulted in a decrease in the index of unsaturation and average fatty acid chain length. Histopathological alterations suggested that the incidence and severity of liver lesions were higher in the mycotoxin-treated laying hens, and the symptoms correlated with the fatty acid profile of total phospholipids. Overall, the findings revealed that mycotoxin exposure, even at the EU-recommended limits, induced lipid peroxidation in the liver, which led to changes in fatty acid composition, matched with tissue damage.

The Lipidome of the Gastrointestinal Tract in Lactating Holstein Cows

The lipidome is a key determinant of structural and functional characteristics of tissues, contributing to optimal gut function and efficiency of nutrient use in the gastrointestinal tract (GIT). Our objective was to study lipidomic profiles in different sections of the GIT in lactating dairy cows and to link them with biological functions. We studied the lipid species in ruminal papillae and epithelium from duodenum, jejunum, and ileum harvested after slaughter from five lactating Holstein cows. Extracted lipids were identified by LC/MS/MS and analyzed via Lipidsearch, Metaboanalyst 5.0, and lipid ontology (LION). Of 1259 lipid species identified across the GIT, 387, 565, 193, and 86 were neutral lipids, phospholipids, sphingolipids, and derivatized lipids, respectively. Among the 1223 lipid species common to the GIT, a PLS-DA analysis revealed similar profiles for jejunum and ileum and discriminated them from rumen and duodenum. The content of 12 out of 28 lipid classes differed (p &lt; 0.05) among GIT sections. The average fatty acid chain length in lipid species spanned from 9 to 37 carbons, and the average degree of unsaturation ranged from 0 to 6. The term ‘membrane component’ from LION analysis differed markedly between the rumen and the small intestine. Future studies will help better understand what factors (function or cellular component) in a given section of the GIT are related to the different lipid species. This is the first description of the lipidome profiles across sections of the GIT in lactating dairy cows. The unique lipidome profiles uncovered distinct structural and functional properties across the bovine GIT, which may impact the efficiency of nutrient use.

Molecular-dynamics-simulation-guided membrane engineering allows the increase of membrane fatty acid chain length in Saccharomyces cerevisiae

The use of lignocellulosic-based fermentation media will be a necessary part of the transition to a circular bio-economy. These media contain many inhibitors to microbial growth, including acetic acid. Under industrially relevant conditions, acetic acid enters the cell predominantly through passive diffusion across the plasma membrane. The lipid composition of the membrane determines the rate of uptake of acetic acid, and thicker, more rigid membranes impede passive diffusion. We hypothesized that the elongation of glycerophospholipid fatty acids would lead to thicker and more rigid membranes, reducing the influx of acetic acid. Molecular dynamics simulations were used to predict the changes in membrane properties. Heterologous expression of Arabidopsis thaliana genes fatty acid elongase 1 (FAE1) and glycerol-3-phosphate acyltransferase 5 (GPAT5) increased the average fatty acid chain length. However, this did not lead to a reduction in the net uptake rate of acetic acid. Despite successful strain engineering, the net uptake rate of acetic acid did not decrease. We suggest that changes in the relative abundance of certain membrane lipid headgroups could mitigate the effect of longer fatty acid chains, resulting in a higher net uptake rate of acetic acid.

Fumonisin B1 induced compositional modifications of the renal and hepatic membrane lipids in rats – Dose and exposure time dependence

ABSTRACTMale Wistar rats were intraperitoneally dosed with fumonisin B1 (FB1; 0, 20, 50 and 100 mg kg−1 dietary dose equivalent) for 5 & 10 days to assess dose- and time-dependent effects on renal and hepatic phosphatidylcholine (PC), phosphatidylinositol (PI) and phosphatidylethanolamine (PE) fatty acid (FA) profiles. Renal PC showed increasing FA saturation (SAT) after 5 days; after 10 days polyunsaturation (PUFA) decreased markedly (Σ n3 (total n3), Σ n6, PUFA, unsaturation index (UI) and average FA chain length (ACL)), mostly with linear dose response. In the PI FAs similar changes were observed, decreasing monounsaturated FA, PUFA, UI and ACL (5 & 10 days), while the PE fraction was responsive in Σ n6 (↓) and SAT (↑), but only after 5 days (without dose response for both PI & PE). Liver PC exhibited increasing saturation (C16:0), decreasing polyunsaturation (C20:3 n6 [dihomo-γ-linolenic acid, DGLA]; C20:3 n3); the PI FA profile showed similar alterations after 5 days. PC & PI FA failed to respond in a dose-dependent manner to FB1. In PE FA profile DGLA decreased, with a decrease of the total n6 FA proportion and dose-dependent increase of n3 FAs. Results revealed expressed renal sensitivity, supporting our earlier published results in terms of oxidative stress and histopathological modifications.

Denovo fatty acid biosynthesis and elongation in very long-chain acyl-CoA dehydrogenase-deficient mice supplemented with odd or even medium-chain fatty acids.

An even medium-chain triglyceride (MCT)-based diet is the mainstay of treatment in very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency (VLCADD). Previous studies with magnetic resonance spectroscopy have shown an impact of MCT on the average fatty acid chain length in abdominal fat. We therefore assume that medium-chain fatty acids (MCFAs) are elongated and accumulate in tissue as long-chain fatty acids. In this study, we explored the hepatic effects of long-term supplementation with MCT or triheptanoin, an odd-chain C7-based triglyceride, in wild-type and VLCAD-deficient (VLCAD(-/-) ) mice after 1year of supplementation as compared with a control diet. The denovo biosynthesis and elongation of fatty acids, and peroxisomal β-oxidation, were quantified by RT-PCR. This was followed by a comprehensive analysis of hepatic and cardiac fatty acid profiles by GC-MS. Long-term application of even and odd MCFAs strongly induced denovo biosynthesis and elongation of fatty acids in both wild-type and VLCAD(-/-) mice, leading to an alteration of the hepatic fatty acid profiles. We detected denovo-synthesized and elongated fatty acids, such as heptadecenoic acid (C17:1n9), eicosanoic acid (C20:1n9), erucic acid (C22:1n9), and mead acid (C20:3n9), that were otherwise completely absent in mice under control conditions. In parallel, the content of monounsaturated fatty acids was massively increased. Furthermore, we observed strong upregulation of peroxisomal β-oxidation in VLCAD(-/-) mice, especially when they were fed an MCT diet. Our data raise the question of whether long-term MCFA supplementation represents the most efficient treatment in the long term. Studies on the hepatic toxicity of triheptanoin are still ongoing.

Characterization of Longissimus thoracis, Semitendinosus and Masseter muscles and relationships with technological quality in pigs. 2. Composition of muscles

The composition of three porcine muscles (Longissimus thoracis: LT, Semitendinosus: ST, Masseter: MS) was characterized and its link with muscle quality was evaluated. The LT muscle had a higher content of tyrosine, tryptophan, and carbohydrates and a lower content of vitamin E and haem iron than the MS muscle, while the ST had similar composition to MS but a lower content of haem iron. Large differences between muscles were observed in relative amounts of most of the major fatty acids. The LT muscle had higher saturated fatty acids (SFA) and n−6:n−3 fatty acid ratio, and lower polyunsaturated fatty acids (PUFA), PUFA:SFA ratio, unsaturation index and average fatty acid chain length than the ST and MS muscles. Muscle pH, redness and chroma were positively correlated with vitamin E and unsaturated lipids and negatively correlated with tyrosine, tryptophan, carbohydrates and saturated lipids, whereas muscle lightness and expressible juice showed similar correlations but an opposite sign with these variables.

A σW‐dependent stress response in Bacillus subtilis that reduces membrane fluidity

Bacteria respond to physical and chemical stresses that affect the integrity of the cell wall and membrane by activating an intricate cell envelope stress response. The ability of cells to regulate the biophysical properties of the membrane by adjusting fatty acid composition is known as homeoviscous adaptation. Here, we identify a homeoviscous adaptation mechanism in Bacillus subtilis regulated by the extracytoplasmic function σ factor σ(W). Cell envelope active compounds, including detergents, activate a sense-oriented, σ(W)-dependent promoter within the first gene of the fabHa fabF operon. Activation leads to a decrease in the amount of FabHa coupled with an increase in FabF, the initiation and elongation condensing enzymes of fatty acid biosynthesis respectively. Downregulation of FabHa results in an increased reliance on the FabHb paralogue leading to a greater proportion of straight chain fatty acids in the membrane, and the upregulation of FabF increases the average fatty acid chain length. The net effect is to reduce membrane fluidity. The inactivation of the σ(W)-dependent promoter within fabHa increased sensitivity to detergents and to antimicrobial compounds produced by other Bacillus spp. Thus, the σ(W) stress response provides a mechanism to conditionally decrease membrane fluidity through the opposed regulation of FabHa and FabF.

In vivo characterization of the liver fat 1H MR spectrum

A theoretical triglyceride model was developed for in vivo human liver fat (1) H MRS characterization, using the number of double bonds (-CH=CH-), number of methylene-interrupted double bonds (-CH=CH-CH(2)-CH=CH-) and average fatty acid chain length. Five 3 T, single-voxel, stimulated echo acquisition mode spectra (STEAM) were acquired consecutively at progressively longer TEs in a fat-water emulsion phantom and in 121 human subjects with known or suspected nonalcoholic fatty liver disease. T(2)-corrected peak areas were calculated. Phantom data were used to validate the model. Human data were used in the model to determine the complete liver fat spectrum. In the fat-water emulsion phantom, the spectrum predicted by the model (based on known fatty acid chain distribution) agreed closely with spectroscopic measurement. In human subjects, areas of CH(2) peaks at 2.1 and 1.3 ppm were linearly correlated (slope, 0.172; r = 0.991), as were the 0.9 ppm CH(3) and 1.3 ppm CH(2) peaks (slope, 0.125; r = 0.989). The 2.75 ppm CH(2) peak represented 0.6% of the total fat signal in high-liver-fat subjects. These values predict that 8.6% of the total fat signal overlies the water peak. The triglyceride model can characterize human liver fat spectra. This allows more accurate determination of liver fat fraction from MRI and MRS.

Proton NMR Spectroscopy of the Phospholipids in Human Uterine Smooth Muscle and Placenta

The parameters regulating the fluidity of myometrial and placental phospholipids include double bonds, fatty acid chain lenght and the cholesterol/phospholipid ratio. The transformation of these parameters was studied during pregnancy and labor. Myometrial and placental tissue samples were collected from 24 patients: 6 were nonpregnant, 6 early-pregnant, 6 late-pregnant not in labor and 6 in labor. After butanol extraction, tissue cholesterol and lipid phosphorus were determined. Proton NMR spectroscopy of the phospholipids was performed at 500 MHz. The myometrial cholesterol/phospholipid ratio was slightly elevated in pregnant patients not in labor. The uterine muscle of the nonpregnant patients contained more CH=CH groups in the phospholipids than that of the late-pregnant patients. There were 29 more double bonds in placental than in uterine tissue per 100 fatty acid molecules. The average fatty acid chain length varied from 14.0 to 18.8. The placenta has longer fatty acid chains than the uterine smooth muscle. The myometrial carbon chain was shortened on the average by 1.4 and the placental by 1.0 carbon atoms, when the patient went into clinical labor. These findings suggest fluidity changes in myometrial and placental phospholipids during human pregnancy and labor.

Membrane lipid composition and glucose uptake in two psychrotolerant bacteria from Antarctica

The thermal responses of membrane lipid composition and function in two bacterial species isolated recently from Heywood Lake sediment in Antarctica have been investigated. Both isolates are Gram-negative psychrotolerant (psychrotrophic) species growing well at 0 and 25 °C, but having very different optimum growth temperatures, of 97 °C for strain CR3/F/w/1/15 and 20·9 °C for strain CR3/F/w/2/10. The acyl lipids in strain 1/15 contain predominantly branched-chain fatty acids, mainly anteiso-15:0. The fatty acid composition and its response to temperature depends on the culture medium used. In nutrient-poor medium a wider range is found, including unsaturated fatty acids, which are absent when a nutrient-rich medium is used. A decrease in growth temperature produced a shortening of the average fatty acid chain length in rich medium, whereas in poor medium there was a decrease in straight chain, saturated and unsaturated relative to branched-chain fatty acids. The acyl lipids of strain 2/10 contain 16:0 and 16:1 as the major fatty acids, particularly in rich medium, when they comprise &gt;90% of the total. Increasing proportions of 16:1 were converted to cyclopropane-17:0 at higher temperatures during growth in poor medium. A decrease in growth temperature in rich or poor medium resulted in an increase in the unsaturation index. When the bacteria were grown in rich or poor medium at 5 °C the strain with more ‘psychrophilic’ characteristics (1/15) took up glucose at a faster rate than did the strain with more ‘psychrotrophic’ characteristics (2/10), whereas when they were grown at 20 °C in either medium the rate of glucose uptake by strain 2/10 was generally faster than that of strain 1/15. Thus, when the bacteria were grown at a low temperature the glucose uptake system of the more ‘psychrophilic’ strain was better adapted to function at zero, compared with that of the more ‘psychrotrophic’ strain. The basis of this difference is not due to the lack of temperature-dependent fatty acid changes, as reported previously for some other cold-adapted bacteria.

Glycosphingolipids from rabbit aorta, plasma, and red blood cells: effects of high cholesterol-high fat diets on fatty acid distribution and quantity of glycosphingolipids

Four glycosphingolipids were isolated from rabbit aorta, plasma, and red blood cells. They were identified, by thin-layer chromatography and by quantitative analysis of hexose and fatty acid, as cerebroside, diglycosyl ceramide, triglycosyl ceramide, and globoside. The rabbits had been maintained on a normal diet or on one of three high cholesterol diets for 180 days. The quantities of the glycosphingolipids and their fatty acid distributions were determined, and comparisons were made between the control and experimental animals. Aorta and plasma glycosphingolipids were more affected by the high cholesterol diets than were those from red blood cells. The effects on aorta and plasma glycosphingolipids were similar. The amount of cerebroside was increased in aorta and plasma in all animals in the experimental groups. The amount was also increased in red blood cells in rabbits from two of the experimental groups. The average fatty acid chain length was greater in the lipids from the experimental animals than in those from the control animals for all measured glycosphingolipids from aorta. The average chain length was also greater in cerebrosides from the experimental animals from all three tissues. Probably the most notable differences in the experimental animals were the increased 24:1/24:0 ratios and the increased concentrations of 24:2. These increases occurred in nearly all samples from plasma and aorta, but not in red blood cells. There was also an increase of total unsaturated fatty acids in aorta cerebrosides from the experimental animals. Except for the increase in 24:2, lard generally caused more deviation from normal than did cottonseed oil when the level of cholesterol in the diet was 1%.

Lipid bilayer structure in the membrane of Mycoplasma laidlawii

X-ray diffraction patterns from intact, isolated Mycoplasma laidlawii membranes at temperatures above and below the thermal phase transition of the membrane lipids reveal important features of the molecular structure of the membrane. (1) The presence of the close hexagonal fatty acid chain packing giving rise to a sharp 4.15 Å diffraction line indicates that the membrane lipids are in a bilayer below the thermal phase transition. (2) The characteristics predicted for the diffraction from a lipid bilayer can be identified in the low-angle patterns from intact membranes both above and below the thermal phase transition, and the differences between the patterns are as expected from the changes in the wideangle pattern. (3) The interpretation of the low-angle patterns is confirmed by changing the average fatty acid chain length and observing the expected changes in the pattern produced by changes in the width of the bilayer. (4) The membrane profile diffraction can be largely accounted for by the lipid bilayer, so the majority of the protein is not located in uniform layers on either side of the bilayer regions of the membrane. (5) The area per lipid molecule is 40 to 45 Å 2 in the membrane bilayer below the transition and 60 to 70 Å 2 above it. Since the lipids are very closely packed, protein cannot penetrate the head group layers below the transition to make hydrophobic contact without disrupting the packing. Furthermore, the lipid-protein interaction does not greatly constrain the spacing of the lipid head groups.

Fatty acids of glycosphingolipids from pig blood fractions

Four glycolipids have been isolated from three fractions of pig blood. The glycolipids were presumably cerebroside, diglycosyl ceramide, triglycosyl ceramide, and globoside. The blood fractions were erythrocytes and plasma high and low density lipoproteins. Fatty acid distributions were determined for each glycolipid as a means to assist in identifying relationships among the several glycolipids. Normal fatty acids predominated in all glycolipids except the globosides from erythrocytes in which the amount of hydroxy acids was slightly greater than the amount of normal acids. Hydroxy acids appeared to be present in all the glycolipids, but the concentration was very low in cerebrosides isolated from high density lipoproteins and erythrocytes, and in diglycosyl ceramide and globoside of the low density lipoproteins. In general, the average fatty acid chain length increased from cerebroside to globoside. This was most apparent in erythrocytes and also greater for normal acids than for hydroxy acids. Fatty acid distributions of erythrocyte glycolipids had sufficient variation to make a metabolic relationship by simple addition of a hexose appear doubtful. While the fatty acid distributions found in plasma lipoproteins were more similar, some means of acyl group selection is probably present for either the synthesis or degradation of these glycolipids.

Fatty acid distribution in mesophilic and thermophilic strains of the genus Bacillus.

The fatty acid distribution of three mesophilic and three thermophilic strains of the genus Bacillus was determined by gas chromatography of the fatty acid methyl esters. Fatty acid i-15:0 was the most abundant in both the mesophiles (51%) and the thermophiles (41%). The second most abundant fatty acid was a-15:0 in the mesophiles (22%), and i-17:0 in the thermophiles (27%). The fatty acid pair i-15:0, i-17:0 was the most predominant pair in both the mesophiles (61%) and the thermophiles (66%). The fatty acid pair a-15:0, a-17:0 was the second most predominant pair and was much higher in the mesophiles (30%) than in the thermophiles (15%). The average fatty acid chain length was 15.5 for the mesophiles and 16.0 for the thermophiles. The significance of these results for the lipid theory of thermophily is discussed.

Quantitative gas-liquid chromatographic analysis of rodent milk triglycerides

A comparison has been made of the milk and adipose tissue triglycerides of rabbits and guinea pigs provided with one diet and of rats and mice provided with another. Both intact triglycerides and component fatty acids were analyzed by gas-liquid chromatography. Good correlation of the data obtained by the two techniques was obtained by calculating the average chain length of the fatty acid moieties. Little difference was found in the triglyceride composition of the adipose tissue of the different species. However, wide variation in the triglyceride composition of the milk was found between the species: the average fatty acid chain length in milk was 11.7 for rabbits, 14.2 for rats, 15.3 for mice, and 17.2 for guinea pigs. The corresponding values for adipose tissue were in the range 16.9-17.4 in all animals. The significance of enzymes that synthesize short-chain fatty acids in mammary gland is discussed.

Gas‐liquid chromatography of triglycerides from erucic acid oils and fish oils

By critically selecting optimum operating conditions, quantitative gas-liquid chromatography of triglycerides has been extended to molecules containing substantial amounts of C(20), C(22), and C(24) fatty acids. The triglycerides of four erucic acid oils (water cress, rapessed, nasturtium, andLunaria annua) and two fully hydrogenated fish oils (menhaden and tuna) have been quantitatively analyzed by this technique. The average fatty acid chain length calculated from the triglyceride composition of each oil agreed closely with that determined by GLC of its respective methyl esters. Several conclusions about the triglyceride composition of the fats analyzed are discussed.