scholarly journals The effect of headgroup methylation on polymorphic phase behaviour in hydrated N-methylated phosphoethanolamine: palmitic acid membranes

Soft Matter ◽  
2021 ◽  
Author(s):  
Matthew Edward Allen ◽  
Yuval Elani ◽  
Nicholas Jan Brooks ◽  
John Seddon

Mixtures of fatty acids and phospholipids can form hexagonal (HII) and inverse bicontinuous cubic phases, the latter of which are implicated in various cellular processes and have wide-ranging biotechnological applications...

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hamza Amine ◽  
Yacir Benomar ◽  
Mohammed Taouis

AbstractSaturated fatty acids such as palmitic acid promote inflammation and insulin resistance in peripheral tissues, contrasting with the protective action of polyunsaturated fatty acids such docosahexaenoic acid. Palmitic acid effects have been in part attributed to its potential action through Toll-like receptor 4. Beside, resistin, an adipokine, also promotes inflammation and insulin resistance via TLR4. In the brain, palmitic acid and resistin trigger neuroinflammation and insulin resistance, but their link at the neuronal level is unknown. Using human SH-SY5Yneuroblastoma cell line we show that palmitic acid treatment impaired insulin-dependent Akt and Erk phosphorylation whereas DHA preserved insulin action. Palmitic acid up-regulated TLR4 as well as pro-inflammatory cytokines IL6 and TNFα contrasting with DHA effect. Similarly to palmitic acid, resistin treatment induced the up-regulation of IL6 and TNFα as well as NFκB activation. Importantly, palmitic acid potentiated the resistin-dependent NFkB activation whereas DHA abolished it. The recruitment of TLR4 to membrane lipid rafts was increased by palmitic acid treatment; this is concomitant with the augmentation of resistin-induced TLR4/MYD88/TIRAP complex formation mandatory for TLR4 signaling. In conclusion, palmitic acid increased TLR4 expression promoting resistin signaling through TLR4 up-regulation and its recruitment to membrane lipid rafts.


Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 665
Author(s):  
Li Zong ◽  
Yan Zhang ◽  
Zhengkang Shao ◽  
Yingwu Wang ◽  
Zheng Guo ◽  
...  

Cytochrome P450 (CYP) mediated enzymatic hydroxylation of fatty acids present a green alternative to chemical synthesis of hydroxy fatty acids (HFAs), which are high-value oleochemicals with various uses in materials industry and medical field. Although many CYPs require the presence of additional reductase proteins for catalytic activity, self-sufficient CYPs have their reductase partner naturally fused into their catalytic domain, leading to a greatly simplified biotransformation process. A recently discovered self-sufficient CYP, BAMF2522 from Bacillus amyloliquefaciens DSM 7, exhibits novel regioselectivity by hydroxylating in-chain positions of palmitic acid generating ω-1 to ω-7 HFAs, a rare regiodiversity profile among CYPs. Besides, F89I mutant of BAMF2522 expanded hydroxylation up to ω-9 position of palmitic acid. Here, we further characterize this enzyme by determining optimum temperature and pH as well as thermal stability. Moreover, using extensive site-directed and site-saturation mutagenesis, we obtained BAMF2522 variants that demonstrate greatly increased regioselectivity for in-chain positions (ω-4 to ω-9) of various medium to long chain fatty acids. Remarkably, when a six-residue mutant was reacted with palmitic acid, 84% of total product content was the sum of ω-7, ω-8 and ω-9 HFA products, the highest in-chain selectivity observed to date with a self-sufficient CYP. In short, our study demonstrates the potential of a recently identified CYP and its mutants for green and sustainable production of a variety of in-chain hydroxy enriched HFAs.


1969 ◽  
Vol 22 (4) ◽  
pp. 1015 ◽  
Author(s):  
TJ Heath ◽  
L N Hill

Normal sheep and sheep with fistulae of the bile duct or the thoracic duct were used to provide quantitative information on the movement of fatty acids into and out of the intestine. The operation used to gain access to the thoracic duct did not cause any significant alteration in the absorption of either [14C]tripalmitin injected into the rumen or [14C]palmitic acid injected into the duodenum. Normal sheep absorbed the major fatty acids oleic (92'1�1'3%), palmitic (87�3�5�0%), and stearic acids (93' 3� 1� 4%) with almost equal efficiency, and the absorption of labelled tri-palmitin injected into the rumen did not alter as the intake of fatty acids increased from 12g/day (90�1�2�3%) to 44g/day (90�1�1�3%).


1985 ◽  
Vol 63 (8) ◽  
pp. 944-951 ◽  
Author(s):  
David L. Severson ◽  
Thea Fletcher

Enzymatic pathways involved in the metabolism of lysophosphatidylcholine were investigated in rat heart myocardial cells. Acyl CoA-dependent acyltransferase activity was localized in microsomes, and was much greater than lysophospholipase activity in either cytosolic or microsomal fractions. The cytosolic lysophospholipase was more sensitive to inhibition by palmitylcarnitine in comparison to free fatty acids. In contrast, free fatty acids (oleate and palmitate) produced a greater inhibition of the microsomal acyltransferase and lysophospholipase than did palmitylcarnitine. A reduction in the assay pH to 6.5 resulted in an increase in microsomal acyltransferase and cytosolic lysophospholipase activities, but brought about a marked reduction in the microsomal lysophospholipase activity. At pH 6.5, the percentage inhibition of the microsomal acyltransferase by palmitylcarnitine was reduced, whereas the inhibition by palmitic acid was enhanced. The inhibition of the microsomal lysophospholipase by both palmitylcarnitine and palmitic acid was reduced at pH 6.5. With respect to myocardial ischemia, the inhibition of microsomal acyltransferase by free fatty acids and the reduction in microsomal lysophospholipase activity due to acidosis may contribute to the elevation of cellular lysophosphoglycerides which are arrhythmogenic.


2016 ◽  
Vol 10 (5) ◽  
pp. 98
Author(s):  
Ali Asghar Ghaemi ◽  
Ali Dindarlou ◽  
Mohammad Taghi Golmakani ◽  
Fatemeh Razzaghi

<p>Olive trees have the capability of growing under semi-arid regions, where drought and salinity are the major concerns. Two years field experiments were carried out to investigate the interaction effects of natural saline well water and irrigation levels on the quantity and quality of fatty acids in the olive flesh fruits (“Roghani” cultivar). A factorial layout within a randomized complete blocks design with three replications of five irrigation levels (I<sub>1</sub> to I<sub>5</sub> as 0.25, 0.5, 0.75, 1 and 1.25 ET<sub>c</sub>) and three saline water levels  (S<sub>1</sub> to S<sub>3</sub> as 100%WW, 50%WW+50%FW and 100%FW) were considered. The fresh and brackish irrigation water were withdrawn from two different natural wells (fresh water (FW) and saline water wells (WW)). <em>Results revealed that <strong>increasing salinity and decreasing irrigation water levels caused significant increment in the ratio of unsaturated fatty acids, palmitic acid to the percentage of oil and oil percentage in olive flesh fruit</strong></em>. It is found that as water<em> </em>salinity increased from lowest to the highest level, the oleic acid trends to its highest value of 23.68% in I<sub>1</sub>S<sub>1</sub>. Mean values of palmitic acid in 2013 were 27.52% and decreased to 19% in 2014. <em>It is concluded that highest percentage of oleic, linoleic, linolenic and palmitic acids obtained under high saline and less applied irrigation treatment (S<sub>1</sub>I<sub>2</sub>) yielding to improve the olive oil quality.</em></p>


Langmuir ◽  
2007 ◽  
Vol 23 (13) ◽  
pp. 7276-7285 ◽  
Author(s):  
Gemma C. Shearman ◽  
Bee J. Khoo ◽  
Mary-Lynn Motherwell ◽  
Kenneth A. Brakke ◽  
Oscar Ces ◽  
...  

Soft Matter ◽  
2017 ◽  
Vol 13 (41) ◽  
pp. 7571-7577 ◽  
Author(s):  
Monika Kluzek ◽  
Arwen I. I. Tyler ◽  
Shiqi Wang ◽  
Rongjun Chen ◽  
Carlos M. Marques ◽  
...  

Cubosomes consist in submicron size particles of lipid bicontinuous cubic phases stabilized by surfactant polymers.


Circulation ◽  
2017 ◽  
Vol 135 (suppl_1) ◽  
Author(s):  
Amanda Fretts ◽  
Fumiaki Imamura ◽  
Chaoyu Yu ◽  
Alexis C Frazier-Wood ◽  
Maria Lankinen ◽  
...  

Background: Circulating saturated fatty acids are biomarkers of diet and metabolism that may influence the pathogenesis of diabetes. Unlike palmitic acid (16:0), which has been extensively studied, little is known of the relationship of very long-chain saturated fatty acids (VLSFAs), with 20 carbons or more, to diabetes risk. Objective: To investigate the associations of circulating levels of VLSFA with incident diabetes. Methods: A meta-analysis was conducted within a consortium of prospective (cohort or nested case-control) studies having circulating measures of one or more VLSFAs, including arachidic acid (20:0), behenic acid (22:0) and lignoceric acid (24:0). Standardized analysis was conducted in each study using pre-specified models, exposures, outcomes, and covariates. Study-specific estimates were pooled using fixed effects meta-analysis. Results: Current findings were based on 9 participating studies, including 46,549 total participants and 13,750 incident diabetes. In multivariable-adjusted analyses, higher levels of all 3 VLSFAs were associated with lower risk of incident diabetes. Pooled RRs (95% CI) per interquintile range were 0.80 (0.71-0.90) for 20:0; 0.83 (0.76-0.91) for 22:0; and 0.70 (0.63-0.79) for 24:0, after adjustment for demographics, lifestyle factors and clinical conditions. Additional adjustments for circulating palmitic acid and triglyceride levels moved the RRs toward the null (illustrated for 24:0, in model 3 of the Figure ). Conclusions: Based on meta-analysis of results from several studies around the world, biomarker levels of VLSFA are associated with lower risk of incident diabetes, potentially mediated by effects on circulating triglycerides and 16:0.


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