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https://www.readbyqxmd.com/read/29753473/dietary-linseed-supplementation-affects-the-fatty-acid-composition-of-the-sn-2-position-of-triglycerides-in-sheep-milk
#1
A Serra, G Conte, F Ciucci, E Bulleri, L Corrales-Retana, A Cappucci, A Buccioni, M Mele
In the human intestine, lipids are absorbed as sn-2 monoglycerides (sn-2, also named β-position), produced mainly by pancreatic lipases, which hydrolysate the triglyceride molecule in positions 1 and 3 (sn-1,3, α-position). The fatty acids esterified in sn-2 are thus preferentially absorbed, which means that the bioavailability of a single fatty acid is affected by its position on the triglyceride. This experiment is carried out with the milk used to make cheese applied in a study with 42 human volunteers...
May 9, 2018: Journal of Dairy Science
https://www.readbyqxmd.com/read/29742444/mixing-behaviour-of-asymmetrical-glycerol-diether-bolalipids-with-saturated-and-unsaturated-phosphatidylcholines
#2
Sindy Müller, Annette Meister, Christian Otto, Gerd Hause, Simon Drescher
Liposomes have received attention as a promising class of drug delivery vehicles. To date, many approaches have been tried developing liposomes for oral use. However, no liposomal formulation is on the market so far that is approved for oral application. In this study, we investigate the miscibility of two glycerol diether bolalipids with classical saturated and unsaturated phosphatidylcholines by means of differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and dynamic light scattering (DLS)...
April 25, 2018: Biophysical Chemistry
https://www.readbyqxmd.com/read/29738257/stereospecific-synthesis-of-1-4-5-6-tetrahydropyrimidines-via-domino-ring-opening-cyclization-of-activated-aziridines-with-%C3%AE-acidic-isocyanides
#3
Aditya Bhattacharyya, Chandan Kumar Shahi, Sajan Pradhan, Manas K Ghorai
An expeditious synthetic route to access structurally diverse 1,4,5,6-tetrahydropyrimidines via domino ring-opening cyclization of activated aziridines with α-acidic isocyanides has been established. The transformation proceeds via Lewis acid mediated SN 2-type ring opening of activated aziridines with α-carbanion of the isocyanides followed by a concomitant 6- endo- dig cyclization in a domino fashion to furnish the 1,4,5,6-tetrahydropyrimidine derivatives in excellent yields (up to 84%) and also in diastereo- and enantiomerically pure form (dr >99:1, ee >99%)...
May 8, 2018: Organic Letters
https://www.readbyqxmd.com/read/29730593/synergistic-effect-between-sulfide-mineral-and-acidophilic-bacteria-significantly-promoted-cr-vi-reduction
#4
Min Gan, Jiayu Li, Shengjie Sun, Jijuan Ding, Jianyu Zhu, Xinxing Liu, Guanzhou Qiu
Natural pyrite was an economical choice for efficient Cr(VI) remediation, while its deep utilization was inhibited due to the passivation effect. In this study, pyrite passivation/dissolution and active sites regeneration mechanism under the activity of acidophilic bacteria with different energy metabolism characteristic in Cr(VI) reduction have been investigated. The reduction capacity was in the order of Acidithiobacillus thiooxidans, Acidithiobacillus ferrooxidans(S), Acidithiobacillus ferrooxidans(Fe), Leptospirillum ferrooxidans and chemical control...
May 3, 2018: Journal of Environmental Management
https://www.readbyqxmd.com/read/29730243/docosahexaenoic-acid-regulates-the-formation-of-lipid-rafts-a-unified-view-from-experiment-and-simulation
#5
Stephen R Wassall, Xiaoling Leng, Samuel W Canner, Edward Ross Pennington, Jacob J Kinnun, Andres T Cavazos, Sahil Dadoo, Dylan Johnson, Frederick A Heberle, John Katsaras, Saame Raza Shaikh
Docosahexaenoic acid (DHA, 22:6) is an n-3 polyunsaturated fatty acid (n-3 PUFA) that influences immunological, metabolic, and neurological responses through complex mechanisms. One structural mechanism by which DHA exerts its biological effects is through its ability to modify the physical organization of plasma membrane signaling assemblies known as sphingomyelin/cholesterol (SM/chol)-enriched lipid rafts. Here we studied how DHA acyl chains esterified in the sn-2 position of phosphatidylcholine (PC) regulate the formation of raft and non-raft domains in mixtures with SM and chol on differing size scales...
May 3, 2018: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29724779/determinants-of-ph-profile-and-acyl-chain-selectivity-in-lysosomal-phospholipase-a2
#6
Vania Hinkovska-Galcheva, Robert J Kelly, Kelly A Manthei, Renee Bouley, Wenmin Yuan, Anna Schwendeman, John J G Tesmer, James A Shayman
Lysosomal phospholipase A2 (LPA2) is characterized by broad substrate recognition, peak activity in acidic pH, and the transacylation of lipophilic alcohols, especially N-acetyl-sphingosine. Prior structural analysis of LPA2 revealed the presence of an atypical acidic residue, Asp13, in the otherwise hydrophobic active site cleft. We hypothesized that Asp13 contributed to the pH profile and/or substrate preference of LPA2 for unsaturated acyl chains. To test this hypothesis, we substituted Asp13 for alanine, cysteine, or phenylalanine; then, we monitored the formation of 1-O-acyl-N-acetylsphingosine to measure the hydrolysis of sn-1 versus sn-2 acyl groups on a variety of glycerophospholipids...
May 3, 2018: Journal of Lipid Research
https://www.readbyqxmd.com/read/29717609/spontaneous-assembly-of-rotaxanes-from-a-primary-amine-crown-ether-and-electrophile
#7
Stephen D P Fielden, David A Leigh, Charlie T McTernan, Borja Pérez-Saavedra, Iñigo J Vitorica-Yrezabal
We report the synthesis of crown ether-ammonium, amide and amine [2]rotaxanes via transition state stabilization of axle-forming reactions. In contrast to the two-step "clipping" and "capping" strategies generally used for rotaxane synthesis, here the components assemble into the interlocked molecule in a single, reagent-less, step under kinetic control. The crown ether accelerates the reaction of the axle-forming components through the cavity to give the threaded product in a form of metal-free active template synthesis...
May 3, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29716614/lewy-body-like-alpha-synuclein-inclusions-trigger-reactive-microgliosis-prior-to-nigral-degeneration
#8
Megan F Duffy, Timothy J Collier, Joseph R Patterson, Christopher J Kemp, Kelvin C Luk, Malú G Tansey, Katrina L Paumier, Nicholas M Kanaan, Luke D Fischer, Nicole K Polinski, Olivia L Barth, Jacob W Howe, Nishant N Vaikath, Nour K Majbour, Omar M A El-Agnaf, Caryl E Sortwell
BACKGROUND: Converging evidence suggests a role for microglia-mediated neuroinflammation in Parkinson's disease (PD). Animal models of PD can serve as a platform to investigate the role of neuroinflammation in degeneration in PD. However, due to features of the previously available PD models, interpretations of the role of neuroinflammation as a contributor to or a consequence of neurodegeneration have remained elusive. In the present study, we investigated the temporal relationship of neuroinflammation in a model of synucleinopathy following intrastriatal injection of pre-formed alpha-synuclein fibrils (α-syn PFFS)...
May 1, 2018: Journal of Neuroinflammation
https://www.readbyqxmd.com/read/29709080/lipidomic-study-of-precursors-of-endocannabinoids-in-freshwater-bryozoan-pectinatella-magnifica
#9
Tomáš Řezanka, Milada Vítová, Jaromír Lukavský, Karel Sigler
Freshwater bryozoan Pectinatella magnifica was collected from a sand pit (South Bohemia). The total lipids after extraction from lyophilized bryozoans were analyzed using high-performance liquid chromatography/high-resolution negative tandem electrospray mass spectrometry. A total of 19 lipid classes were identified, including N-acyl-substituted phospholipids, that is, N-acylphosphatidylethanolamine and N-acylphosphatidylserine in their plasmenyl forms. Based on gas chromatography/mass spectrometry of 3-pyridylcarbonyl (picolinyl) esters, a very unusual fatty acid was identified, namely 24:7n-3 (all-cis-3,6,9,12,15,18,21-tetracosaheptaenoic acid)...
April 30, 2018: Lipids
https://www.readbyqxmd.com/read/29678574/a-novel-1-acyl-sn-glycerol-3-phosphate-o-acyltransferase-homolog-for-the-synthesis-of-membrane-phospholipids-with-a-branched-chain-fatty-acyl-group-in-shewanella-livingstonensis-ac10
#10
Yosuke Toyotake, Hyun-Nam Cho, Jun Kawamoto, Tatsuo Kurihara
1-Acyl-sn-glycerol-3-phosphate O-acyltransferase (PlsC) plays an essential role in the formation of phosphatidic acid, a precursor of various membrane phospholipids (PLs), in bacteria by catalyzing the introduction of an acyl group into the sn-2 position of lysophosphatidic acid. Various bacteria produce more than one PlsC. However, the physiological significance of the occurrence of multiple PlsCs is poorly understood. A psychrotrophic bacterium, Shewanella livingstonensis Ac10, which produces eicosapentaenoic acid at low temperatures, has five putative PlsCs (PlsC1-5)...
April 17, 2018: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/29676056/pseudocapacitive-sodium-storage-by-ferroelectric-sn-2-p-2-s-6-with-layered-nanostructure
#11
Sheng Huang, Chao Meng, Min Xiao, Shan Ren, Shuanjin Wang, Dongmei Han, Yuning Li, Yuezhong Meng
Sodium ion batteries (SIB) are considered promising alternative candidates for lithium ion batteries (LIB) because of the wide availability and low cost of sodium, therefore the development of alternative sodium storage materials with comparable performance to LIB is urgently desired. The sodium ions with larger sizes resist intercalation or alloying because of slow reaction kinetics. Most pseudocapacitive sodium storage materials are based on subtle nanomaterial engineering, which is difficult for large-scale production...
April 19, 2018: Small
https://www.readbyqxmd.com/read/29673706/lysophosphatidylcholine-acyltransferase-3-deficiency-impairs-3t3l1-cell-adipogenesis-through-activating-wnt-%C3%AE-catenin-pathway
#12
Chunyan Feng, Bin Lou, Jibin Dong, Zhiqiang Li, Yunqin Chen, Yue Li, Xuemei Zhang, Xian-Cheng Jiang, Tingbo Ding
Levels of polyunsaturated phosphatidylcholine (PC) influence plasma membrane structure and function. Phosphatidylcholine (PC) is synthesized de novo in the Kennedy pathway and then undergoes extensive deacylation/reacylation remodeling via Lands' cycle (non-Kennedy pathway). The reacylation is catalyzed by lysophosphatidylcholine acyltransferase (LPCAT), which adds a polyunsaturated fatty acid at the sn-2 position. Four LPCAT isoforms have been described to date, among which we found LPCAT3 to be the major isoform in adipose tissue, but its exact role in adipogenesis is unclear...
April 16, 2018: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29670910/regiospecific-analysis-of-fatty-acids-and-calculation-of-triglyceride-molecular-species-in-marine-fish-oils
#13
Huijun Zhang, Yingbin Shen, Youwei Zhang, Lirong Li, Xingguo Wang
The regiospecific distribution of fatty acids (FAs) and composition of triglyceride (TAG) molecular species of fishes were analyzed and calculated by pancreatic lipase (PL) hydrolysis and Visual Basic (VB) program. DHA was preferentially located at sn-2 position in TAG molecule, whereas EPA was almost equally distributed in each position of glycerol backbone. DOP, DPP, EPP, PoPP, PPO, and PPP were the predominant TAG species. MPP in anchovy, DDP, DOP, DPP in tuna, and EOO and OOO in salmon were the characteristic TAG molecules, which were meaningful to differentiate marine fish oils...
2018: BioMed Research International
https://www.readbyqxmd.com/read/29659053/chiral-syntheses-of-methyl-r-2-sulfanylcarboxylic-esters-and-acids-with-optical-purity-determination-using-hplc
#14
Ryosuke Sasaki, Yoo Tanabe
Accessible chiral syntheses of 3 types of (R)-2-sulfanylcarboxylic esters and acids were performed: (R)-2-sulfanylpropanoic (thiolactic) ester (53%, 98%ee) and acid (39%, 96%ee), (R)-2-sulfanylsucciinic diester (59%, 96%ee), and (R)-2-mandelic ester (78%, 90%ee) and acid (59%, 96%ee). The present practical and robust method involves (i) clean SN 2 displacement of methanesulfonates of (S)-2-hydroxyesters by using commercially available AcSK with tris(2-[2-methoxyethoxy])ethylamine and (ii) sufficiently mild deacetylation...
April 16, 2018: Chirality
https://www.readbyqxmd.com/read/29652437/effect-of-thermal-processing-towards-lipid-oxidation-and-non-enzymatic-browning-reactions-of-antartic-krill-euphausia-superba-meal
#15
Yanzi Liu, Peixu Cong, Beijia Li, Yu Song, Yanjun Liu, Jie Xu, Changhu Xue
BACKGROUND: Antarctic krill is a huge source of biomass and prospective high-quality lipid source. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), nutritionally important lipid components with poor oxidative stability, were used as markers of oxidation during thermal processing of Antarctic krill (Euphausia superba) meal by evaluating the lipolysis, lipid oxidation, and non-enzymatic browning reactions. RESULT: Liquid chromatography-mass spectrometry of the phospholipids (PLs) and the main oxidation products of free fatty acids (FFAs) and phosphatidylcholine (PC) was effective for evaluating the oxidation of EPA and DHA...
April 13, 2018: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/29629138/conservation-of-direct-dynamics-in-sterically-hindered-s-n-2-e2-reactions
#16
Eduardo Carrascosa, Jennifer Meyer, Tim Michaelsen, Martin Stei, Roland Wester
Nucleophilic substitution (SN 2) and base-induced elimination (E2), two indispensable reactions in organic synthesis, are commonly assumed to proceed under stereospecific conditions. Understanding the way in which the reactants pre-orient in these reactions, that is its stereodynamics, is essential in order to achieve a detailed atomistic picture and control over such processes. Using crossed beam velocity map imaging, we study the effect of steric hindrance in reactions of Cl- and CN- with increasingly methylated alkyl iodides by monitoring the product ion energy and scattering angle...
January 21, 2018: Chemical Science
https://www.readbyqxmd.com/read/29629137/diastereodivergent-asymmetric-michael-alkylation-reactions-using-chiral-n-n-dioxide-metal-complexes
#17
Yulong Kuang, Bin Shen, Li Dai, Qian Yao, Xiaohua Liu, Lili Lin, Xiaoming Feng
A diastereodivergent asymmetric Michael-alkylation reaction between 3-chloro-oxindoles and β,γ-unsaturated-α-ketoesters has been achieved using L-RaPr2 /Sc(OTf)3 and L-PrPr2 /Mg(OTf)2 metal complexes as catalysts. Both rel -(1 R ,2 S ,3 R ) and rel -(1 S ,2 S ,3 R ) chiral spiro cyclopropane oxindoles were constructed in good yields, diastereoselectivities and ee values. The diastereodivergent control may originate from different alkylation pathways after the Michael addition, with either intramolecular trapping of the aza- ortho -xylylene intermediate or direct SN 2 substitution...
January 21, 2018: Chemical Science
https://www.readbyqxmd.com/read/29621644/new-phenophospholipids-equipped-with-multi-functionalities-regiospecific-synthesis-and-characterization
#18
Sampson Anankanbil, Bianca Pérez, Chiranjib Banerjee, Zheng Guo
HYPOTHESIS: In multi-phase systems, many complex reactions take place at the interface where a molecule equipped with manifold functionalities is demanded. By taking advantage of the surface-active property of phosphatidylcholine (PC) scaffold and antioxidant properties of phenolic acids, new multifunctional molecules are generated, which are expected to confer physical and oxidative stability to sensitive bioactive ingredients in delivery systems. EXPERIMENTS: This work reports a successful synthesis of two new arrays of phenophospholipids sn-1-acyl(C12-C18)-sn-2-caffeoyl and sn-1-caffeoyl-sn-2-acyl phosphatidylcholines via mild scalable regiospecific pathways; as structurally verified by MS,1 H/13 C NMR analyses, and characterized by critical micelle concentrations (CMC), FTIR, and DSC analysis...
March 28, 2018: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/29621568/effect-of-an-experimental-mouth-rinse-containing-naf-and-tif-4-on-tooth-erosion-and-abrasion-in-situ
#19
Beatriz Martines de Souza, Larissa Rodrigues Pereira Santi, Mayara de Souza Silva, Marília Afonso Rabelo Buzalaf, Ana Carolina Magalhães
OBJECTIVE: This study compared the effect of an experimental NaF/TiF4 mouth rinse with a commercial tin/F mouth rinse on the prevention of tooth wear in situ. METHODS: Fifteen subjects took part in this crossover and double-blind study, in which they wore a palatal appliance with 8 bovine teeth samples (4 enamel and 4 root dentine) in each of 3 phases (5 days each). Half of the samples were subjected to erosive challenges, and the other half to erosive plus abrasive challenges...
April 2, 2018: Journal of Dentistry
https://www.readbyqxmd.com/read/29604859/sn-2-stabilization-in-masni-3-perovskites-by-superhalide-incorporation
#20
Junxiang Xiang, Kan Wang, Bin Xiang, Xudong Cui
Sn-based hybrid halide perovskites are a potential solution to replace Pb and thereby reduce Pb toxicity in MAPbI3 perovskite-based solar cells. However, the instability of Sn2+ in air atmosphere causes a poor reproducibility of MASnI3 , hindering steps towards this goal. In this paper, we propose a new type of organic metal-superhalide perovskite of MASnI2 BH4 and MASnI2 AlH4 . Through first-principles calculations, our results reveal that the incorporation of BH4 and AlH4 superhalides can realize an impressive enhancement of oxidation resistance of Sn2+ in MASnI3 perovskites because of the large electron transfer between Sn2+ and [BH4 ]- /[AlH4 ]- ...
March 28, 2018: Journal of Chemical Physics
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