Search results for "phospholipids"

Brain choline has a typical precursor profile.

1998

Choline is product and precursor to both acetylcholine and membrane phospholipids, and, in the brain, is ultimately provided by the circulation. The brain is protected from excess choline and choline deprivation by a refined system of homeostatic mechanisms that maintain a level of extracellular choline that, for its role as precursor, meets saturation criteria under normal conditions. The kinetic and activity profiles of choline are typical for a biosynthetic precursor.

Scanning Force Microscopy of Artificial Membranes

2002

Visualization of biological membranes by scanning force microscopy (SFM) has tremendously improved the current understanding of protein ‐ lipid interactions under physiological conditions. SFM is the only tool to directly image processes on surfaces in aqueous solution at molecular resolution. Besides being a supportive means to confirm results on lipid phases and domains obtained from fluorescence spectroscopy, calorimetry, and X-ray crystallography, SFM has contributed distinct aspects on the formation of 2D crystals of various membrane-confined proteins and morphological changes of membranes due to the interaction of peptides and proteins. This review will focus on recent results in SFM …

Procoagulant activities of skeletal muscle and cardiac myosins require both myosin protein and myosin-associated anionic phospholipids

2021

Conformational transitions of gramicidin A in phospholipid model membranes. A high-performance liquid chromatography assessment.

1991

We have investigated the conformation of gramicidin A reconstituted in different phospholipid environments, small unilamellar vesicles, extensive bilayers, and micelles by exploiting a recently proposed experimental approach based on high-performance liquid chromatography [Bano et al. (1988) J. Chromatogr. 458, 105; Bano et al. (1989) FEBS Lett. 250, 67]. The method allows the separation of conformational species of the peptide namely, antiparallel double-stranded (APDS) dimers and β 6.3 -helical monomers, and quantitation of their proportions in the lipid environment. Various experimental parameters (e.g., nature of organic solvent, time of incubation in organic solvent, lipid-to-peptide m…

Metabolomics of the effect of AMPK activation by AICAR on human umbilical vein endothelial cells

2011

AMP-activated protein kinase (AMPK) is a metabolic master switch expressed in a great number of cells and tissues. AMPK is thought to modulate the cellular response to different stresses that increase cellular AMP concentration. The adenosine analog, 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) is an AMPK activator used in many studies to assess the effects of AMPK activation on cellular metabolism and function. However, the effect of AICAR on cell metabolism reaches many different pathways and metabolites, some of which do not seem to be fully related to AMPK activation. We have now for the first time used NMR metabolomics on human umbilical vein endothelial cells (HUVEC) fo…

Probes for studying cholesterol binding and cell biology.

2011

Cholesterol is a multifunctional lipid in eukaryotic cells. It regulates the physical state of the phospholipid bilayer, is crucially involved in the formation of membrane microdomains, affects the activity of many membrane proteins, and is the precursor for steroid hormones and bile acids. Thus, cholesterol plays a profound role in the physiology and pathophysiology of eukaryotic cells. The cholesterol molecule has achieved evolutionary perfection to fulfill its different functions in membrane organization. Here, we review basic approaches to explore the interaction of cholesterol with proteins, with a particular focus on the high diversity of fluorescent and photoreactive cholesterol prob…

The application of phospholipid removal columns and ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry for quantificati…

2016

In this study a robust and sensitive method based on a proposed sample purification procedure, using zirconia-coated Phree™ columns and analysis by ultra-high performance liquid chromatography with triple quadrupole tandem mass spectrometry are presented for the assessment of multi-class antibiotics in farmed fish species. The sample preparation procedure benefited from combined precipitation of proteins and selective removal of phospholipids by Phree™ columns, resulting in a high sensitivity of the method (LOQ 0.3-9mgkg(-1)). The in-house validation results (precision, repeatability, decision limit CCα, detection capability CCβ, etc.) indicate that the elaborated method is fully suitable f…

Changes in fatty acid compositions of total serum and lipoprotein particles, in growing rats given protein-deficient diets with either hydrogenated c…

1994

The present study examines the effects of dietary saturated (hydrogenated coconut oil) and polyunsaturated (salmon oil) fats on the composition and metabolism of lipoproteins in growing rats fed on protein-deficient diets. Four groups of rats were fed on the following diets for 28 d: 200 g casein+50 g coconut oil (COC)/kg, 20 g casein+50 g coconut oil (COd)/kg, 200 g casein + 50 g salmon oil (SAC)/kg, 20 g casein+50 g salmon oil (SAd)/kg. Both protein-deficient groups exhibited low concentrations of protein and triacylglycerol (in serum, very-low-density lipoprotein (VLDL), low-density lipoprotein-high-density lipoprotein, (LDL-HDL1) and HDL2-3), of cholesterol (in LDL-HDL1) and of phosphol…

Cyclopropanation of Membrane Unsaturated Fatty Acids Is Not Essential to the Acid Stress Response of Lactococcus lactis subsp. cremoris

2011

ABSTRACT Cyclopropane fatty acids (CFAs) are synthetized in situ by the transfer of a methylene group from S -adenosyl- l -methionine to a double bond of unsaturated fatty acid chains of membrane phospholipids. This conversion, catalyzed by the Cfa synthase enzyme, occurs in many bacteria and is recognized to play a key role in the adaptation of bacteria in response to a drastic perturbation of the environment. The role of CFAs in the acid tolerance response was investigated in the lactic acid bacterium Lactococcus lactis MG1363. A mutant of the cfa gene was constructed by allelic exchange. The cfa gene encoding the Cfa synthase was cloned and introduced into the mutant to obtain the comple…

Sphingobium aromaticiconvertens sp. nov., a xenobiotic-compound-degrading bacterium from polluted river sediment.

2007

A bacterial strain capable of degrading some monochlorinated dibenzofurans, designated RW16T, was isolated from aerobic River Elbe sediments. The strain was characterized based on 16S rRNA gene sequence analysis, DNA G+C content, physiological characteristics, polyamines, ubiquinone and polar lipid pattern and fatty acid composition. This analysis revealed that strain RW16T represents a novel species of the genus Sphingobium. The DNA G+C content of strain RW16T, 60.7 mol%, is the lowest yet reported for the genus. 16S rRNA gene sequence analysis placed strain RW16T as an outlier in the genus Sphingobium. The name Sphingobium aromaticiconvertens sp. nov. is proposed for this dibenzofuran-min…