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101.
Caroline Fauquant Valérie Briard‐Bion Nadine Leconte Michel Guichardant Marie‐Caroline Michalski 《European Journal of Lipid Science and Technology》2007,109(12):1167-1173
Native milk fat globules of various mean diameters, ranging from d43 = 2.3 µm to 8.0 µm, were obtained using microfiltration of raw whole milk. After milk fat globule washing, the milk fat globule membrane (MFGM) was separated by manual churning. After total lipid extraction and separation of polar lipids, their phospholipid (PL) and sterol composition was measured using thin‐layer chromatography, methyl ester analyses by gas chromatography, and gas chromatography coupled to mass spectrometry. The main PL species were phosphatidylethanolamine, phosphatidylcholine and sphingomyelin. The respective fatty acid composition of each PL species was measured. Many different minor bioactive sterols were detected in the MFGM, e.g. lanosterol, lathosterol, desmosterol, stigmasterol and β‐sitosterol. No significant differences in the PL and sterol profile were found between MFGM extracted from small and large milk fat globule fractions. 相似文献
102.
Delagrave Simon; Goldman Ellen R.; Youvan Douglas C. 《Protein engineering, design & selection : PEDS》1995,8(3):237-242
Two different combinatorial mutagenesis experiments on the light-harvestingII (LH2) protein of Rhodobacter capsulatus indicate that heuristicrules relating sequence directly to phenotype are dependenton which sets or groups of residues are mutated simultaneously.Previously reported combinatorial mutagenesis of this chromogenicprotein (based on both phylogenetic and structural models) showedthat substituting amino acids with large molar volumes at Glyß31caused the mutated protein to have a spectrum characteristicof light-harvesting I (LH1). The six residues that underwentcombinatorial mutagenesis were modeled to lie on one side ofa transmembrane -helix that binds bacteriochlorophyll. In asecond experiment described here, we have not used structuralmodels or phylogeny in choosing mutagenesis sites. Instead,a set of six contiguous residues was selected for combinatorialmutagenesis. In this latter experiment, the residue substitutedat Glyß31 was not a determining factor in whetherLH2 or LH1 spectra were obtained; therefore, we conclude thatthe heuristic rules for phenotype prediction are context dependent.While phenotype prediction is context dependent, the abilityto identify elements of primary structure causing phenotypediversity appears not to be. This strengthens the argument forperforming combinatorial mutagenesis with an arbitrary groupingof residues if structural models are unavailable. 相似文献
103.
Dong H. Cha Alejandro E. Mieles Paola F. Lahuatte Andrea Cahuana Marie Piedad Lincango Charlotte E. Causton Sabine Tebbich Arno Cimadom Stephen A. Teale 《Journal of chemical ecology》2016,42(11):1101-1111
We investigated the role of olfactory cues from actively fermenting yeast (Saccharomyces cerevisiae) in attraction of adult Philornis downsi and identified two synergistically attractive yeast volatiles. Larvae of this invasive fly parasitize the hatchlings of passerines and threaten the Galapagos avifauna. Gas chromatography coupled with electroantennographic detection (GC-EAD), coupled gas chromatography-mass spectrometry (GC-MS), and field trapping experiments were used to identify volatile compounds from a yeast-sugar solution. EAD responses were consistently elicited by 14 yeast volatiles. In a series of field trapping experiments, a mixture of the 14 EAD-active compounds was similarly attractive to P. downsi when compared to the yeast-sugar solution, and we found that acetic acid and ethanol were essential for attraction. A mixture of 0.03 % acetic acid and 3 % ethanol was as attractive as the 14-component blend, but was not as attractive as the yeast-sugar solution. Philornis downsi showed positive and negative dose-responses to acetic acid in the ranges of 0.01 ~ 0.3 % and 0.3 ~ 9 %, respectively. Further optimization showed that the mixture of 1 % acetic acid and 3 % ethanol was as attractive as the yeast-sugar solution. Both mixtures of acetic acid and ethanol were more selective than the yeast-sugar solution in terms of non-target moths and Polistes versicolor wasps captured. These results indicate that acetic acid and ethanol produced by yeasts are crucial for P. downsi attraction to fermented materials on which they feed as adults and can be used to manage this invasive fly in Galapagos. 相似文献
104.
Margeaux A. Miller Prof. Dr. Ellen M. Sletten 《Chembiochem : a European journal of chemical biology》2020,21(24):3451-3462
Perfluorocarbons, saturated carbon chains in which all the hydrogen atoms are replaced with fluorine, form a separate phase from both organic and aqueous solutions. Though perfluorinated compounds are not found in living systems, they can be used to modify biomolecules to confer orthogonal behavior within natural systems, such as improved stability, engineered assembly, and cell-permeability. Perfluorinated groups also provide handles for purification, mass spectrometry, and 19F NMR studies in complex environments. Herein, we describe how the unique properties of perfluorocarbons have been employed to understand and manipulate biological systems. 相似文献
105.
Jenny Do Gani Perez Bahafta Berhe Nahid Tayebi Ellen Sidransky 《International journal of molecular sciences》2021,22(13)
Mutations in GBA1, the gene encoding glucocerebrosidase, are common genetic risk factors for Parkinson disease (PD). While the mechanism underlying this relationship is unclear, patients with GBA1-associated PD often have an earlier onset and faster progression than idiopathic PD. Previously, we modeled GBA1-associated PD by crossing gba haploinsufficient mice with mice overexpressing a human mutant α-synuclein transgene (SNCAA53T), observing an earlier demise, shorter life span and faster symptom progression, although behavioral testing was not performed. To assess whether gba+/−//SNCAA53T mice exhibit a prodromal behavioral phenotype, we studied three cardinal PD features: olfactory discrimination, memory dysfunction, and motor function. The longitudinal performance of gba+/−//SNCAA53T (n = 8), SNCAA53T (n = 9), gba+/− (n = 10) and wildtype (n = 6) mice was evaluated between ages 8 and 23 months using the buried pellet test, novel object recognition test and the beam walk. Fifteen-month-old gba+/−//SNCAA53T mice showed more olfactory and motor deficits than wildtype mice. However, differences between gba+/−//SNCAA53T and SNCAA53T mice generally did not reach statistical significance, possibly due to small sample sizes. Furthermore, while gba haploinsufficiency leads to a more rapid demise, this might not result in an earlier prodromal stage, and other factors, including aging, oxidative stress and epigenetics, may contribute to the more fulminant disease course. 相似文献
106.
Muscimol Directly Activates the TREK-2 Channel Expressed in GABAergic Neurons through Its N-Terminus
Eun-Jin Kim Oh-Sang Kwon Chang-Gi Hur Marie Merci Nyiramana Dong-Kun Lee Seong-Geun Hong Jaehee Han Dawon Kang 《International journal of molecular sciences》2021,22(17)
The two-pore domain K+ (K2P) channel, which is involved in setting the resting membrane potential in neurons, is an essential target for receptor agonists. Activation of the γ-aminobutyric acid (GABA) receptors (GABAAR and GABABR) reduces cellular excitability through Cl- influx and K+ efflux in neurons. Relatively little is known about the link between GABAAR and the K+ channel. The present study was performed to identify the effect of GABAR agonists on K2P channel expression and activity in the neuroblastic B35 cells that maintain glutamic acid decarboxylase (GAD) activity and express GABA. TASK and TREK/TRAAK mRNA were expressed in B35 cells with a high level of TREK-2 and TRAAK. In addition, TREK/TRAAK proteins were detected in the GABAergic neurons obtained from GABA transgenic mice. Furthermore, TREK-2 mRNA and protein expression levels were markedly upregulated in B35 cells by GABAAR and GABABR agonists. In particular, muscimol, a GABAAR agonist, significantly increased TREK-2 expression and activity, but the effect was reduced in the presence of the GABAAR antagonist bicuculine or TREK-2 inhibitor norfluoxetine. In the whole-cell and single-channel patch configurations, muscimol increased TREK-2 activity, but the muscimol effect disappeared in the N-terminal deletion mutant. These results indicate that muscimol directly induces TREK-2 activation through the N-terminus and suggest that muscimol can reduce cellular excitability by activating the TREK-2 channel and by inducing Cl- influx in GABAergic neurons. 相似文献
107.
Preparation of glycol derivatives of partially hydrogenated soybean oil fatty acids and their potential as lubricants 总被引:1,自引:0,他引:1
Hemendra N. Basu Ellen M. Robley Max E. Norris 《Journal of the American Oil Chemists' Society》1994,71(11):1227-1230
Glycol diesters and mixtures of mono- and diesters have been prepared from methyl esters of partially hydrogenated soybean
oil fatty acids and diethylene, dipropylene, neopentyl and triethylene glycols. The catalyst used in these reactions was a
mixture of calcium acetate/barium acetate (3∶1, w/w). The reactions were carried out under nitrogen with 0.5% catalyst at
temperatures in the range of 190–275°C. Borated esters of mixed mono- and diesters were prepared with 0.33 equivalent of boric
acid per 1.0 equivalent hydroxyl group on the ester. Refractive indices, viscosities, and flash and fire points were determined
for diesters, mixed mono- and diesters, and mixed diesters and borated esters. The viscosities, flash points and fire points
indicate that these esters can be used as a component of lubricating oils. Wear-prevention characteristics of mixed diesters
and borated esters indicated that they can be used as antifriction additives in lubricating oils.
Lecture presented at the joint meeting of the International Society for Fat Research and the American Oil Chemists' Society
in Toronto, May 10, 1992. 相似文献
108.
Anne‐Marie Demers Ryan Gosselin Jean‐Sébastien Simard Nicolas Abatzoglou 《加拿大化工杂志》2012,90(2):299-303
This work proposes a novel chemometric methodology for in‐line near infrared spectroscopy (NIRS) monitoring of pharmaceutical powder moisture in a fluidised‐bed dryer. The collected spectra are analysed by multivariate chemometrics involving the preparation of numerous laboratory samples. A different methodology, using only plant samples, was tested in real‐time. A specially designed probe tip, allowing for robust in‐situ spectral acquisition, was designed. The results prove that NIRS can be as efficient as traditional quality analyses, e.g. loss‐on‐drying, in measuring powder moisture content in a fluidised bed dryer with a calibration model based only on plant samples. © 2011 Canadian Society for Chemical Engineering 相似文献
109.
Synthetic and Biological Studies of Sesquiterpene Polygodial: Activity of 9‐Epipolygodial against Drug‐Resistant Cancer Cells 下载免费PDF全文
Dr. Ramesh Dasari Annelise De Carvalho Derek C. Medellin Kelsey N. Middleton Dr. Frédéric Hague Marie N. M. Volmar Prof. Liliya V. Frolova Dr. Mateus F. Rossato Jorge J. De La Chapa Nicholas F. Dybdal‐Hargreaves Akshita Pillai Prof. Véronique Mathieu Prof. Snezna Rogelj Prof. Cara B. Gonzales Prof. João B. Calixto Prof. Antonio Evidente Dr. Mathieu Gautier Dr. Gnanasekar Munirathinam Prof. Rainer Glass Prof. Patricia Burth Dr. Stephen C. Pelly Prof. Willem A. L. van Otterlo Prof. Robert Kiss Prof. Alexander Kornienko 《ChemMedChem》2015,10(12):2014-2026
Polygodial, a terpenoid dialdehyde isolated from Polygonum hydropiper L., is a known agonist of the transient receptor potential vanilloid 1 (TRPV1). In this investigation a series of polygodial analogues were prepared and investigated for TRPV1‐agonist and anticancer activities. These experiments led to the identification of 9‐epipolygodial, which has antiproliferative potency significantly exceeding that of polygodial. 9‐Epipolygodial was found to maintain potency against apoptosis‐resistant cancer cells as well as those displaying the multidrug‐resistant (MDR) phenotype. In addition, the chemical feasibility for the previously proposed mechanism of action of polygodial, involving the formation of a Paal–Knorr pyrrole with a lysine residue on the target protein, was demonstrated by the synthesis of a stable polygodial pyrrole derivative. These studies reveal rich chemical and biological properties associated with polygodial and its direct derivatives. These compounds should inspire further work in this area aimed at the development of new pharmacological agents, or the exploration of novel mechanisms of covalent modification of biological molecules with natural products. 相似文献
110.
Preparation and Reinforcement of Dual‐Porous Biocompatible Cellulose Scaffolds for Tissue Engineering 下载免费PDF全文
Nicole Pircher David Fischhuber Leticia Carbajal Christine Strauß Jean‐Marie Nedelec Cornelia Kasper Thomas Rosenau Falk Liebner 《大分子材料与工程》2015,300(9):911-924
Biocompatible cellulose‐based aerogels composed of nanoporous struts, which embed interconnected voids of controlled micron‐size, have been prepared employing temporary templates of fused porogens, reinforcement by interpenetrating PMMA networks and supercritical carbon dioxide drying. Different combinations of cellulose solvent (Ca(SCN)2/H2O/LiCl or [EMIm][OAc]/DMSO) and anti‐solvent (EtOH), porogen type (paraffin wax or PMMA spheres) and porogen size (various fractions in the range of 100–500 μm) as well as intensity of PMMA reinforcement have been investigated to tailor the materials for cell scaffolding applications. All aerogels exhibited an open and dual porosity (micronporosity >100 μm and nanoporosity extending to the low micrometer range). Mechanical properties of the dual‐porous aerogels under compressive stress were considerably improved by introduction of interpenetrating PMMA networks. The effect of the reinforcing polymer on attachment, spreading, and proliferation of NIH 3T3 fibroblast cells, cultivated on selected dual‐porous aerogels to pre‐evaluate their biocompatibility was similarly positive. 相似文献