scholarly journals Different rates of flux through the biosynthetic pathway for long-chain versus very-long-chain sphingolipids

2020 ◽  
Vol 61 (10) ◽  
pp. 1341-1346
Author(s):  
Iris D. Zelnik ◽  
Giora Volpert ◽  
Leena E. Viiri ◽  
Dimple Kauhanen ◽  
Tamar Arazi ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Chain Length ◽  
Biosynthetic Pathway ◽  
Acyl Chain ◽  
Degree Of Saturation ◽  
Disease States ◽  
Acyl Chain Length ◽  
Long Chain Base ◽  
Acyl Chains ◽  
Long Chain

The backbone of all sphingolipids (SLs) is a sphingoid long-chain base (LCB) to which a fatty acid is N-acylated. Considerable variability exists in the chain length and degree of saturation of both of these hydrophobic chains, and recent work has implicated ceramides with different LCBs and N-acyl chains in distinct biological processes; moreover, they may play different roles in disease states and possibly even act as prognostic markers. We now demonstrate that the half-life, or turnover rate, of ceramides containing diverse N-acyl chains is different. By means of a pulse-labeling protocol using stable-isotope, deuterated free fatty acids, and following their incorporation into ceramide and downstream SLs, we show that very-long-chain (VLC) ceramides containing C24:0 or C24:1 fatty acids turn over much more rapidly than long-chain (LC) ceramides containing C16:0 or C18:0 fatty acids due to the more rapid metabolism of the former into VLC sphingomyelin and VLC hexosylceramide. In contrast, d16:1 and d18:1 ceramides show similar rates of turnover, indicating that the length of the sphingoid LCB does not influence the flux of ceramides through the biosynthetic pathway. Together, these data demonstrate that the N-acyl chain length of SLs may not only affect membrane biophysical properties but also influence the rate of metabolism of SLs so as to regulate their levels and perhaps their biological functions.

scholarly journals The elongation of exogenous fatty acids and the control of phospholipid acyl chain length in Micrococcus cryophilus

1980 ◽  
Vol 188 (3) ◽  
pp. 585-592 ◽  
Author(s):  
S P Sandercock ◽  
N J Russell
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Chain Length ◽  
De Novo ◽  
Acyl Chain ◽  
Psychrophilic Bacterium ◽  
Fatty Acid Elongation ◽  
Acyl Chain Length ◽  
Acyl Chains ◽  
Phospholipid Acyl Chain

The synthesis of fatty acids de novo from acetate and the elongation of exogenous satuated fatty acids (C12-C18) by the psychrophilic bacterium Micrococcus cryophilus (A.T.C.C. 15174) grown at 1 or 20 degrees C was investigated. M. cryophilus normally contains only C16 and C18 acyl chains in its phospholipids, and the C18/C16 ratio is altered by changes in growth temperature. The bacterium was shown to regulate strictly its phospholipid acyl chain length and to be capable of directly elongating myristate and palmitate, and possibly laurate, to a mixture of C16 and C18 acyl chains. Retroconversion of stearate into palmitate also occurred. Fatty acid elongation could be distinguished from fatty acid synthesis de novo by the greater sensitivity of fatty acid elongation to inhibition by NaAsO2 under conditions when the supply of ATP and reduced nicotinamide nucleotides was not limiting. It is suggested that phospholipid acyl chain length may be controlled by a membrane-bound elongase enzyme, which interconverts C16 and C18 fatty acids via a C14 intermediate; the activity of the enzyme could be regulated by membrane lipid fluidity.

scholarly journals Effect of different long-chain fatty acids on cholecystokinin releasein vitroand energy intake in free-living healthy males

2012 ◽  
Vol 108 (4) ◽  
pp. 755-758 ◽  
Author(s):  
Charlotte J. Harden ◽  
Adam N. Jones ◽  
Tannia Maya-Jimenez ◽  
Margo E. Barker ◽  
Natalie J. Hepburn ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Chain Length ◽  
Energy Intake ◽  
Acyl Chain ◽  
Dependent Manner ◽  
Long Chain Fatty Acids ◽  
Long Chain ◽  
Healthy Males ◽  
Cck Release ◽  
Chain Fatty Acids

Long-chain fatty acids have been shown to suppress appetite and reduce energy intake (EI) by stimulating the release of gastrointestinal hormones such as cholecystokinin (CCK). The effect of NEFA acyl chain length on these parameters is not comprehensively understood. Anin vitroscreen tested the capacity of individual NEFA (C12 to C22) to trigger CCK release. There was a gradient in CCK release with increasing chain length. DHA (C22) stimulated significantly (P < 0·01) more CCK release than all other NEFA tested. Subsequently, we conducted a randomised, controlled, crossover intervention study using healthy males (n18). The effects of no treatment (NT) and oral doses of emulsified DHA-rich (DHA) and oleic acid (OA)-rich oils were compared using 24 h EI as the primary endpoint. Participants reported significantly (P = 0·039) lower total daily EI (29 % reduction) with DHA compared to NT. There were no differences between DHA compared to OA and OA compared to NT. There was no between-treatment difference in the time to, or EI of, the first post-intervention eating occasion. It is concluded that NEFA stimulate CCK release in a chain length-dependent manner up to C22. These effects may be extended to thein vivosetting, as a DHA-based emulsion significantly reduced short-term EI.

Lipid profiling of human diabetic myocardium reveals differences in triglyceride fatty acyl chain length and degree of saturation

2020 ◽  
Vol 320 ◽  
pp. 106-111
Author(s):  
Elias Björnson ◽  
Ylva Östlund ◽  
Marcus Ståhlman ◽  
Martin Adiels ◽  
Elmir Omerovic ◽  
...  
Keyword(s):  
Chain Length ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Degree Of Saturation ◽  
Fatty Acyl Chain ◽  
Lipid Profiling ◽  
Acyl Chain Length ◽  
Diabetic Myocardium

scholarly journals Lipid remodelling during epididymal maturation of rat spermatozoa. Enrichment in plasmenylcholines containing long-chain polyenoic fatty acids of the n-9 series

1992 ◽  
Vol 283 (1) ◽  
pp. 235-241 ◽  
Author(s):  
M I Aveldaño ◽  
N P Rotstein ◽  
N T Vermouth
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Acyl Chain ◽  
Sperm Maturation ◽  
High Concentration ◽  
Lipid Domain ◽  
Choline Glycerophospholipids ◽  
Epididymal Maturation ◽  
Acyl Chains ◽  
Long Chain

In their transit from the caput to the cauda segments of the epididymis, rat spermatozoa undergo significant modifications in lipid content and composition. The amount of lipid phosphorus per cell decreases, and most lipid classes show specific changes in their constituent fatty acids. A depletion of phosphatidylcholine and phosphatidylethanolamine, concomitant with a virtually unchanged amount of the corresponding plasmalogens, are the major alterations, plasmenylcholine thereby becoming the major phospholipid. Diphosphatidylglycerol, sphingomyelin and the phosphoinositides decrease to a lesser extent or do not change at all, also resulting in relative increases with sperm maturation. Concerning the fatty acids, the proportions of oleate (C18:1, n-9) and linoleate (C18:2, n-6) in most lipids decrease on movement of sperm from caput to cauda, augmenting in turn the proportions of longer-chain (C20 to C24) and more unsaturated fatty acids. Docosapentaenoate (C22:5, n-6) is a major acyl chain present in all lipids at both stages, but uncommon long-chain polyenoic fatty acids of the n-9 series are also present, being almost exclusively found in the choline glycerophospholipids. These fatty acids are found to undergo the most significant changes during sperm maturation. They are minor components of plasmenylcholine in immature spermatozoa, but increase severalfold on maturation, representing more than half of the acyl chains of this major lipid in cells from the cauda. The high concentration of n-9 polyenes in mature sperm plasmenylcholine raises intriguing questions on the possible role epididymal cells may play in providing spermatozoa with such an unusual phospholipid. These plasmenylcholines could contribute to the characteristic lipid domain organization of the mature spermatozoa plasma membrane.

scholarly journals Endocytic Trafficking of Sphingomyelin Depends on Its Acyl Chain Length

2007 ◽  
Vol 18 (12) ◽  
pp. 5113-5123 ◽  
Author(s):  
Mirkka Koivusalo ◽  
Maurice Jansen ◽  
Pentti Somerharju ◽  
Elina Ikonen
Keyword(s):  
Plasma Membrane ◽  
Chain Length ◽  
Human Fibroblasts ◽  
Acyl Chain ◽  
Endocytic Trafficking ◽  
Dependent Manner ◽  
Lipid Trafficking ◽  
Acyl Chain Length ◽  
Escrt Complex ◽  
Long Chain

To study the principles of endocytic lipid trafficking, we introduced pyrene sphingomyelins (PyrSMs) with varying acyl chain lengths and domain partitioning properties into human fibroblasts or HeLa cells. We found that a long-chain, ordered-domain preferring PyrSM was targeted Hrs and Tsg101 dependently to late endosomal compartments and recycled to the plasma membrane in an NPC1- and cholesterol-dependent manner. A short-chain, disordered domain preferring PyrSM recycled more effectively, by using Hrs-, Tsg101- and NPC1-independent routing that was insensitive to cholesterol loading. Similar chain length-dependent recycling was observed for unlabeled sphingomyelins (SMs). The findings 1) establish acyl chain length as an important determinant in the endocytic trafficking of SMs, 2) implicate ESCRT complex proteins and NPC1 in the endocytic recycling of ordered domain lipids to the plasma membrane, and 3) introduce long-chain PyrSM as the first fluorescent lipid tracing this pathway.

Effect of Alkyl Chain Length on Molecular Heat Transfer Characteristics in Lipid Bilayers

2011 ◽  
Author(s):  
Takeo Nakano ◽  
Gota Kikugawa ◽  
Taku Ohara
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Lipid Bilayers ◽  
Chain Length ◽  
Phosphatidyl Choline ◽  
Acyl Chain ◽  
Nonequilibrium Molecular Dynamics ◽  
Acyl Chain Length ◽  
Acyl Chains ◽  
Dynamics Simulations

Nonequilibrium molecular dynamics simulations are carried out on single component lipid bilayers with ambient water in order to investigate the effect of acyl chain length on heat transport characteristics along and across the membranes. In this study, dipalmitoyl-phosphatidyl-choline (DPPC), dilauroyl-phosphatidyl-choline (DLPC), and stearoyl-myristoyl-phosphatidyl-choline (SMPC) which has two acyl chains of both sixteen C atoms, both twelve C atoms, and eighteen and fourteen C atoms, respectively, were used as lipid molecules. In the direction along the membranes, thermal conductivity corresponds with that of each membrane. On the other hand, in the direction across membrane, the highest thermal resistance exists at the center of lipid bilayer where lipid acyl chains face each other. However, asymmetric chain length reduces thermal resistance at the interface between lipid monolayers. Therefore, thermal conductivity across the membrane which consists of asymmetric chain length is higher than those which consist of symmetric chain length.

Effects of fatty acid chain length and saturation on gastric inhibitory polypeptide release in obese hyperglycaemic (ob/ob) mice

1985 ◽  
Vol 5 (8) ◽  
pp. 701-705 ◽  
Author(s):  
Piotr Kwasowski ◽  
Peter R. Flatt ◽  
Clifford J. Bailey ◽  
Vincent Marks
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Chain Length ◽  
Gastric Inhibitory Polypeptide ◽  
Chain Fatty Acid ◽  
Short Chain ◽  
Degree Of Saturation ◽  
Gip Release ◽  
Long Chain ◽  
Chain Fatty Acids

Plasma gastric inhibitory polypeptide (GIP) responses to equimolar intragastrically administered emulsions of fatty acids (2.62 mmol/7.5 ml/kg) were examined in 18 h fasted obese hyperglycaemic (ob/ob) mice. Propionic acid (C3:0), a saturated short-chain fatty acid, and capric acid (C10:0), a saturated medium chain fatty acid, did not signilicantly stimulate GIP release. However, the saturated long-chain fatty acid stearic acid (C18:0), and especially the unsaturated long-chain fatty acids oleic (C18:1), linoleic (C18:2) and linolenic (C18:3) acids produced a marked GIP response. The results show that chain length and to a lesser extent the degree of saturation are important determinants of fatty acid-stimulated GIP release. The GIP-release action of long-chain, but not short-chain, fatty acids may be related to differences in their intracellular handling.

scholarly journals Acyl-chain specificity of human milk bile-salt-activated lipase

1991 ◽  
Vol 279 (1) ◽  
pp. 297-302 ◽  
Author(s):  
C S Wang
Keyword(s):  
Human Milk ◽  
Bile Salt ◽  
Chain Length ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Acyl Chain Length ◽  
Enzyme Substrate ◽  
Consistent Trend ◽  
Kinetics Of ◽  
Long Chain

In order to probe the active-site structure of human milk bile-salt-activated lipase (BAL), the kinetics of the BAL-catalysed reaction were studied using monoesters as substrates. Among the fatty acyl chains, ranging from C8 to C16 of monoacylglycerols in a single equimolar assay mixture, there was a consistent trend of increased reactivity with decreased fatty-acyl-chain length for both the basal and taurocholate-stimulated activities of BAL. In addition, the detection of hydrolysis of long-chain monoacylglycerols in the absence of bile salt indicates that it is possible for the long-chain fatty acid monoester to form an enzyme-substrate complex with the basal form of BAL. I further examined the reaction kinetics of BAL with water-soluble short-chain esters of p-nitrophenol. The results indicated that there is a consistent trend towards a decreased Michaelis-Menten constant with increased acyl-chain length. Therefore it was concluded that the decreased reactivity with increased acyl-chain length of acylglycerols is probably not a consequence of the lowered affinity of the substrate for the enzyme. The fact that butyrate ester has the optimum acyl chain to be a substrate of BAL can be attributed to its acyl-chain length being long enough for interaction with the active centre of BAL and short enough to provide adequate positioning of the ester bond for transition state complex formation. The calculated free energy of BAL catalysis based on the derived kinetic parameters provides additional insight into the effect on the enzyme-substrate interaction of increasing the number of methylene groups in the acyl chain of substrates.

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