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membrane fluidity

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https://www.readbyqxmd.com/read/28634761/unveiling-the-compositional-variety-of-cardiolipins-in-rhodobacter-sphaeroides-by-liquid-chromatography-with-electrospray-ionization-and-multistage-collision-induced-dissociation-mass-spectrometry
#1
Sara Granafei, Ilario Losito, Massimo Trotta, Angela Agostiano, Francesco Palmisano, Tommaso R I Cataldi
Cardiolipins (CL) contained in the lipid extracts of the photosynthetic bacterium Rhodobacter sphaeroides (strain R26) were systematically characterized by reversed-phase liquid chromatography coupled to electrospray ionization mass spectrometry, performed in single (MS), tandem (MS/MS) and sequential (MS(3)) modes using a linear ion trap mass spectrometer. The total number of carbon atoms and C=C bonds of each CL and, subsequently, those related to each of the constituting phosphatidic acid (PA) units, along with the location of the latter on the central glycerol backbone, were inferred from MS and MS/MS data, respectively...
June 20, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28627734/role-of-cytoskeletal-mechanics-and-cell-membrane-fluidity-in-the-intracellular-delivery-of-molecules-mediated-by-laser-activated-carbon-nanoparticles
#2
Stefany Y Holguin, Caleb F Anderson, Naresh N Thadhani, Mark R Prausnitz
Exposure of cells and nanoparticles to near-infrared nanosecond pulsed laser light can lead to efficient intracellular delivery of molecules while maintaining high cell viability by a photoacoustic phenomenon known as transient nanoparticle energy transduction (TNET). Here, we examined the influence of cytoskeletal mechanics and plasma membrane fluidity on intracellular uptake of molecules and loss of cell viability due to TNET. We found that destabilization of actin filaments using latrunculin A led to greater uptake of molecules and less viability loss caused by TNET...
June 19, 2017: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/28627570/determination-of-bending-rigidity-and-tilt-modulus-of-lipid-membranes-from-real-space-fluctuation-analysis-of-molecular-dynamics-simulations
#3
M Doktorova, D Harries, G Khelashvili
We have recently developed a novel computational methodology (termed RSF for Real-Space Fluctuations) to quantify the bending rigidity and tilt modulus of lipid membranes from real-space analysis of fluctuations in the tilt and splay degrees of freedom as sampled in molecular dynamics (MD) simulations. In this article, we present a comprehensive study that combines results from the application of the RSF method to a wide range of lipid bilayer systems that encompass membranes of different fluidities and sizes, including lipids with saturated and unsaturated lipid tails, single and multi-component lipid systems, as well as non-standard lipids such as the four-tailed cardiolipin...
June 19, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28620695/liposomes-modified-by-mono-and-bis-phthalocyanines-a-comprehensive-epr-study
#4
Dariusz Man, Rudolf Słota, Anna Kawecka, Grzegorz Engel, Gabriela Dyrda
The impact of selected metallophthalocyanines, featuring diverse molecular structure, upon the fluidity of liposome membranes was studied using the spin label EPR technique. The "mono"-type MPc's (M = Zn, Sn; Pc = C32H16N8 is the phthalocyanine ligand) and sandwich LnPc2 complexes (Ln = Nd, Sm, Gd) were explored. Liposomes were obtained in a sonication process, from egg yolk lecithin (EYL) in water. TEMPO and 16-DOXYL spin labels were used to monitor the peripheral and central part of the lipid double layer, respectively, which allowed to localize the phthalocyanine additive within the bilayer, as well as to perform independent measurements of changes in fluidity upon addition thereof...
June 2017: European Physical Journal. E, Soft Matter
https://www.readbyqxmd.com/read/28611746/adaptations-to-high-salt-in-a-halophilic-protist-differential-expression-and-gene-acquisitions-through-duplications-and-gene-transfers
#5
Tommy Harding, Andrew J Roger, Alastair G B Simpson
The capacity of halophiles to thrive in extreme hypersaline habitats derives partly from the tight regulation of ion homeostasis, the salt-dependent adjustment of plasma membrane fluidity, and the increased capability to manage oxidative stress. Halophilic bacteria, and archaea have been intensively studied, and substantial research has been conducted on halophilic fungi, and the green alga Dunaliella. By contrast, there have been very few investigations of halophiles that are phagotrophic protists, i.e., protozoa...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28606538/antibacterial-activity-and-mechanisms-of-depolymerized-fucoidans-isolated-from-laminaria-japonica
#6
Ming Liu, Yixiang Liu, Min-Jie Cao, Guang-Ming Liu, Qingchou Chen, Lechang Sun, Haixiu Chen
Fucoidans, sulfated polysaccharides in brown algae, were depolymerized though high-pressure hydrolysis, and their antibacterial activity, structural properties, and antibacterial mechanisms were investigated in this work. The fucoidans from Laminaria japonica show no antibacterial activity before depolymerization; however, their depolymerized products can effectively (p<0.05) inhibit the proliferation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The structure-activity study demonstrated that lower molecular weight and stronger polyanionic property can promote the antibacterial activity...
September 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28592113/ph-dependent-lipid-vesicle-interactions-with-plasma-polymerized-thin-films
#7
Hannah J Askew, Mirren Charnley, Karyn L Jarvis, Sally L McArthur
Model lipid vesicle and supported lipid bilayer (SLB) systems are used in a variety of applications including biosensing, cell membrane mimics, and drug delivery. Exposure of a surface to a vesicle solution provides a straightforward method for creating such systems via vesicle adsorption and collapse. However, this process is complex and the relationship between the surface physicochemical properties and vesicle collapse is poorly understood. Plasma polymers are thin conformal films that can be applied to a variety of materials to modify surface properties...
June 7, 2017: Biointerphases
https://www.readbyqxmd.com/read/28591608/ceramide-c16-is-a-versatile-modulator-of-phosphatidylethanolamine-polymorphism
#8
Mahmoudreza Doroudgar, Michel Lafleur
Ceramide-C16 (CerC16) is a sphingolipid associated with several diseases like diabetes, obesity, Parkinson disease, and certain types of cancers. As a consequence, research efforts are devoted to identify the impact of CerC16 on the behavior of membranes, and to understand how it is involved in these diseases. In this work, we investigated the impacts of CerC16 (up to 20 mol %) on the lipid polymorphism of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), using differential scanning calorimetry, and sequential (2)H and (31)P solid-state nuclear magnetic resonance spectroscopy...
June 6, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28588281/a-central-small-amino-acid-in-the-vamp2-transmembrane-domain-regulates-the-fusion-pore-in-exocytosis
#9
Benoît Hastoy, Pier A Scotti, Alexandra Milochau, Zahia Fezoua-Boubegtiten, Jorge Rodas, Rémi Megret, Bernard Desbat, Michel Laguerre, Sabine Castano, David Perrais, Patrik Rorsman, Reiko Oda, Jochen Lang
Exocytosis depends on cytosolic domains of SNARE proteins but the function of the transmembrane domains (TMDs) in membrane fusion remains controversial. The TMD of the SNARE protein synaptobrevin2/VAMP2 contains two highly conserved small amino acids, G100 and C103, in its central portion. Substituting G100 and/or C103 with the β-branched amino acid valine impairs the structural flexibility of the TMD in terms of α-helix/β-sheet transitions in model membranes (measured by infrared reflection-absorption or evanescent wave spectroscopy) during increase in protein/lipid ratios, a parameter expected to be altered by recruitment of SNAREs at fusion sites...
June 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28588277/effects-of-hydraulic-retention-time-on-adsorption-behaviours-of-eps-in-an-a-o-mbr-biofouling-study-with-qcm-d
#10
Xudong Wang, Botao Cheng, Cunrui Ji, Miao Zhou, Lei Wang
Extra-cellular polymeric substances (EPS) are a major cause of membrane fouling in membrane bioreactors (MBRs). In this study, an anoxic-oxic membrane bioreactor (A/O-MBR) was run continuously for 98 days. The runs were divided into three stages according to hydraulic retention time (HRT) (11.8, 12.5 and 14.3 h, respectively). EPS were extracted from the reactor under the different HRTs. A quartz crystal microbalance with dissipation monitoring (QCM-D) and Fourier transform infrared (FT-IR) were used to study the adherence layer structures and the adsorption behaviours of EPS on the membrane surface...
June 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28585042/characterizing-the-interactions-of-two-lipid-modifications-with-lipid-rafts-farnesyl-anchors-vs-palmitoyl-anchors
#11
Tao Zhang, Qichao Luo, Linlin Yang, Hualiang Jiang, Huaiyu Yang
Farnesyl (Far) and palmitoyl (Pal) anchors play important roles in the traffic of many lipidated proteins. Herein, we show the distinctive interactions and influences of the two lipid modifications on lipid rafts (LRs) and non-raft-like membranes using molecular dynamics simulations. Palmitoyl anchors behave in a more ordered fashion, pack tighter with the lipids of LRs and diffuse at a slower rate than farnesyl anchors in LRs. When interacting with non-raft-like membranes these two types of anchors become less ordered, pack more loosely with lipids, and diffuse at a higher rate...
June 5, 2017: European Biophysics Journal: EBJ
https://www.readbyqxmd.com/read/28572611/transcriptome-responses-of-lactobacillus-acetotolerans-f28-to-a-short-and-long-term-ethanol-stress
#12
Xiaopan Yang, Kunling Teng, Jie Zhang, Fangfang Wang, Tong Zhang, Guomin Ai, Peijie Han, Fengyan Bai, Jin Zhong
Lactobacillus acetotolerans is a major microbe contributing to the Chinese liquor fermentation with unknown function. It can be grown well in a high concentration of ethanol. RNA sequencing (RNA-seq) was performed on L. acetotolerans F28 growing in 12% ethanol to determine important genetic mechanisms for both a short and long term adaption to this environment. A genome-wide transcriptional analysis revealed that the most important genetic elements for L. acetotolerans F28 grown in ethanol are related to high levels of stress response and fatty acid biosynthesis, and a reduction of amino acid transport and metabolism after both a short and long time stress...
June 1, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28549727/topographic-analysis-by-atomic-force-microscopy-of-proteoliposomes-matrix-vesicle-mimetics-harboring-tnap-and-anxa5
#13
Maytê Bolean, Ivana A Borin, Ana M S Simão, Massimo Bottini, Luis A Bagatolli, Marc F Hoylaerts, José L Millán, Pietro Ciancaglini
Atomic force microscopy (AFM) is one of the most commonly used scanning probe microscopy techniques for nanoscale imaging and characterization of lipid-based particles. However, obtaining images of such particles using AFM is still a challenge. The present study extends the capabilities of AFM to the characterization of proteoliposomes, a special class of liposomes composed of lipids and proteins, mimicking matrix vesicles (MVs) involved in the biomineralization process. To this end, proteoliposomes were synthesized, composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dipalmitoyl-sn-glycero-3-phospho-L-serine (DPPS), with inserted tissue-nonspecific alkaline phosphatase (TNAP) and/or annexin V (AnxA5), both characteristic proteins of osteoblast-derived MVs...
May 23, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28548854/curcumin-protects-membranes-through-carpet-or-insertion-model-depending-on-hydration
#14
Richard J Alsop, Alexander Dhaliwal, Maikel C Rheinstadter
Curcumin is the main ingredient of turmeric, a common Indian spice. Curcumin shows a broad spectrum of effects, including anti-Alzheimer's and anti-oxidant properties. An interaction between curcumin and lipid membranes has been speculated as the root-cause, and the molecule is often proposed to `protect' the bilayer. However, the detailed molecular mechanism of this protection is disputed. There is evidence that curcumin either a) lies flat on the bilayer and provides a `carpet' for protection by forming a steric barrier, or b) inserts into the membrane and stiffens tails, thereby protecting against peptide insertion...
May 26, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28539592/atorvastatin-promotes-phagocytosis-and-attenuates-pro-inflammatory-response-in-human-retinal-pigment-epithelial-cells
#15
Bo Tian, Ahmad Al-Moujahed, Peggy Bouzika, Yijun Hu, Shoji Notomi, Pavlina Tsoka, Joan W Miller, Haijiang Lin, Demetrios G Vavvas
Phagocytosis of daily shed photoreceptor outer segments is an important function of the retinal pigment epithelium (RPE) and it is essential for retinal homeostasis. RPE dysfunction, especially impairment of its phagocytic ability, plays an essential role in the pathogenesis of age-related macular degeneration (AMD). Statins, or HMG CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase inhibitors, are drugs with multiple properties that have been extensively used to treat hyperlipidemia. However, their effect on RPE cells has not been fully elucidated...
May 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28536001/membrane-shaping-by-actin-and-myosin-during-regulated-exocytosis
#16
REVIEW
Andreas Papadopulos
The cortical actin network in neurosecretory cells is a dense mesh of actin filaments underlying the plasma membrane. Interaction of actomyosin with vesicular membranes or the plasma membrane is vital for tethering, retention, transport as well as fusion and fission of exo- and endocytic membrane structures. During regulated exocytosis the cortical actin network undergoes dramatic changes in morphology to accommodate vesicle docking, fusion and replenishment. Most of these processes involve plasma membrane Phosphoinositides (PIP) and investigating the interactions between the actin cortex and secretory structures has become a hotbed for research in recent years...
May 20, 2017: Molecular and Cellular Neurosciences
https://www.readbyqxmd.com/read/28534301/effects-of-acetyl-l-carnitine-in-diabetic-neuropathy-and-other-geriatric-disorders
#17
REVIEW
G Sergi, S Pizzato, F Piovesan, C Trevisan, N Veronese, E Manzato
A long history of diabetes mellitus and increasing age are associated with the onset of diabetic neuropathy, a painful and highly disabling complication with a prevalence peaking at 50% among elderly diabetic patients. Acetyl-L-carnitine (ALC) is a molecule derived from the acetylation of carnitine in the mitochondria that has an essential role in energy production. It has recently been proposed as a therapy to improve the symptoms of diabetic neuropathy. ALC is widely distributed in mammalian tissues, including the brain, blood-brain barrier, brain neurons, and astrocytes...
May 22, 2017: Aging Clinical and Experimental Research
https://www.readbyqxmd.com/read/28531236/psychosine-enhances-the-shedding-of-membrane-microvesicles-implications-in-demyelination-in-krabbe-s-disease
#18
Ludovic D'Auria, Cory Reiter, Emma Ward, Ana Lis Moyano, Michael S Marshall, Duc Nguyen, Giuseppe Scesa, Zane Hauck, Richard van Breemen, Maria I Givogri, Ernesto R Bongarzone
In prior studies, our laboratory showed that psychosine accumulates and disrupts lipid rafts in brain membranes of Krabbe's disease. A model of lipid raft disruption helped explaining psychosine's effects on several signaling pathways important for oligodendrocyte survival and differentiation but provided more limited insight in how this sphingolipid caused demyelination. Here, we have studied how this cationic inverted coned lipid affects the fluidity, stability and structure of myelin and plasma membranes...
2017: PloS One
https://www.readbyqxmd.com/read/28522594/sphingomyelin-synthase-2-deficiency-inhibits-the-induction-of-murine-colitis-associated-colon-cancer
#19
Toshio Ohnishi, Chieko Hashizume, Makoto Taniguchi, Hidehiro Furumoto, Jia Han, Rongfen Gao, Shinichi Kinami, Takeo Kosaka, Toshiro Okazaki
Sphingomyelin synthase 2 (SMS2) is the synthetic enzyme of sphingomyelin (SM), which regulates membrane fluidity and microdomain structure. SMS2 plays a role in LPS-induced lung injury and inflammation; however, its role in inflammation-mediated tumorigenesis is unclear. We investigated the effect of SMS2 deficiency on dextran sodium sulfate (DSS)-induced murine colitis and found inhibition of DSS-induced inflammation in SMS2-deficient (SMS2(-/-)) mice. DSS treatment induced a significant increase in ceramide levels, with a decrease of SM levels in SMS2(-/-) colon tissue, and demonstrated attenuation of the elevation of both inflammation-related gene expression and proinflammatory cytokines and chemokines, leukocyte infiltration, and MAPK and signal transducer and activator of transcription 3 activation...
May 18, 2017: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
https://www.readbyqxmd.com/read/28513911/sperm-capacitation-pretreatment-positively-impacts-bovine-intracytoplasmic-sperm-injection
#20
L Águila, F Zambrano, M E Arias, Felmer R
The efficiency of intracytoplasmic sperm injection (ICSI) in bovines is low compared to other species due in part to inadequate egg activation and sperm nucleus decondensation after injection. We hypothesized that this low efficiency is due to the lack of complete sperm capacitation, so we evaluated the effects of isobutylmethylxanthine (IBMX) and methyl-β-cyclodextrin (MβCD) on bovine sperm capacitation and on the preimplantation developmental potential of bovine embryos generated by ICSI. Treatment with IBMX and MβCD decreased sperm viability (between 13 to 30%); nevertheless, 0...
May 17, 2017: Molecular Reproduction and Development
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