Clear protocols for the study of membrane lipid properties, cellular transport or signal transduction are presented in this manual. Following a short introduction to membrane lipids, techniques for the isolation and extraction of membrane fractions, the analysis of the lipid composition, lipid turnover, and the involvement in signal transduction as well as the preparation of liposomes are : Paperback.. Clear protocols for the study of membrane lipid properties, cellular transport or signal transduction are Manual on Membrane Lipids. Authors: Prasad, Rajendra Free Preview.. Buy this book eB08 About this book. Clear protocols for the study of membrane lipid properties, cellular transport or signal transduction are presented in this manual. Following a short introduction to membrane lipids, techniques for the isolation and extraction of membrane fractions, the analysis of the lipid composition, lipid turnover, and the involvement in signal transduction as well as the preparation of liposomes are ...

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TY - JOUR. T1 - Low doses of ethanol have Ca2+ ionophore-like effects on apical membrane potential of in vitro Necturus antrum. AU - Rutten, Michael. AU - Moore, C. D.. PY - 1991. Y1 - 1991. N2 - The effects of low doses of luminal ethanol on the amiloride-sensitive apical membrane potential of Necturus antral mucosa were studied using conventional microelectrode techniques. Luminal ethanol (0.250-4.0% vol/vol) caused a dose-dependent hyperpolarization of the apical membrane potential (V(mc)), an increase in transepithelial resistance (R(t)) and resistance ratio (R(a)/R(b)), and a decrease in transepithelial potential (V(ms)). Luminal amiloride (100 μM) to 4% ethanol-treated antra did not cause any additional hyperpolarization of V(mc). Compared with luminal 2% ethanol-Ringer, an equivalent osmotic mannitol solution depolarized V(mc) and basolateral potential (V(cs)), decreased R(t) and R(a)/R(b), and increased V(ms). A single dose of 0.50% ethanol attenuated the effects of a second 2% ethanol ...

TY - CHAP. T1 - Introduction: Regulatory processes, an emerging feature in intracellular membrane traffic. AU - Keränen, Sirkka. AU - Jäntti, Jussi. PY - 2004. Y1 - 2004. N2 - The subject of this volume is the molecular mechanism of the intracellular membrane trafficking, a central eukaryotic cell biological process. In the post genomic era, essential molecules involved in intracellular membrane/protein transport are emerging with increasing pace. The present challenge is to compile the molecular networks that govern these processes. Understanding of regulatory processes and participating molecules are likely to reveal global cellular regulatory circuits that couple membrane trafficking with other cellular functions. The part of the membrane transport machinery, which forms stabile protein complexes is rather well known already. However, the regulatory mechanisms that link these more stabile complexes to other cellular functions are only starting to emerge. This book focuses on the regulatory ...

TY - JOUR. T1 - Characterization of apical and basolateral plasma membrane domains derived from cultured rat cholangiocytes. AU - Tietz, Pamela. AU - Levine, Susan. AU - Holman, Ralph. AU - Fretham, Chris. AU - La Russo, Nicholas F. PY - 1997/12/15. Y1 - 1997/12/15. N2 - Cholangiocytes, the epithelial cells that line intrahepatic bile ducts, are composed of plasma membranes with discrete apical (lumenal) and basolateral domains that contain different channels, transporters, and receptors. In recent work, we developed a long-term, primary culture system of normal rat cholangiocytes (NRC). Our aims here were to prepare and characterize apical and basolateral plasma membrane vesicles from NRC. Using serial isopycnic centrifugation on sucrose gradients, we generated separate apical and basolateral plasma membrane vesicles. We characterized these vesicles by transmission electron microscopy, specific marker enzyme assays, and immunoblotting; we also determined the percentage of sealed vesicles and ...

Cholesterol- and glycosphingolipid-enriched membrane lipid microdomains, frequently called lipid rafts, are thought to play an important role in the spatial and temporal organization of immunological synapses. Higher ordering of lipid acyl chains was suggested for these entities and imaging of membrane order in living cells during activation can therefore help to understand the mechanisms responsible for the supramolecular organization of molecules involved in the activation of T cells. Here, we employ the phase-sensitive membrane dye di-4-ANEPPDHQ together with a variety of spectrally-resolved microscopy techniques, including 2-channel ratiometric TIRF microscopy and fluorescence lifetime imaging, to characterize membrane order at the T cell immunological synapse at high spatial and temporal resolution in live cells at physiological temperature. We find that higher membrane order resides at the immunological synapse periphery where proximal signalling through the immunoreceptors and accessory proteins

Table_1_Role of Neutral Sphingomyelinase-2 (NSM 2) in the Control of T Cell Plasma Membrane Lipid Composition and Cholesterol Homeostasis.DOCX

Gloeobacter violaceus sp. PCC 7421 is an unusual cyanobacterium with only one cellular membrane, which lacks the thylakoid membranes found in other oxygenic photosynthetic organisms. The cell membrane lipids in G. violaceus sp. PCC 7421 are monogalactosyl diacylglycerol, digalactosyl diacylglycerol, phosphatidyl glycerol and phosphatidic acid in the molar proportion of 51, 24, 18 and 4% respectively. This lipid composition resembles that of the cell membrane from other cyanobacteria, but completely lacks sulfoquinovosyl diacylglycerol. This lack of sulfoquinovosyl diacylglycerol is exceptional for a photosynthetic membrane. The membrane lipids are esterified to 14:0, 16:0, 16:1, 18:0, 18:1, 18:2 and alpha 18:3 fatty acids.. ...

TY - JOUR. T1 - Chloride equilibrium potential in salamander cones. AU - Thoreson, Wallace B. AU - Bryson, Eric J.. PY - 2004/12/5. Y1 - 2004/12/5. N2 - Background: GABAergic inhibition and effects of intracellular chloride ions on calcium channel activity have been proposed to regulate neurotransmission from photoreceptors. To assess the impact of these and other chloride-dependent mechanisms on release from cones, the chloride equilibrium potential (ECl) was determined in red-sensitive, large single cones from the tiger salamander retinal slice. Results: Whole cell recordings were done using gramicidin perforated patch techniques to maintain endogenous Cl- levels. Membrane potentials were corrected for liquid junction potentials. Cone resting potentials were found to average -46 mV. To measure ECl, we applied long depolarizing steps to activate the calcium-activated chloride current (ICl(Ca)) and then determined the reversal potential for the current component that was inhibited by the Cl- ...

purpose. Tetraphenylphosphonium (TPP+) is a permeant lipophilic cation that accumulates in cultured cells and tissues as a function of the electrical membrane potential across the plasma membrane. This study was undertaken to determine whether TPP+ can be used for assessing membrane potential in intact lenses in organ culture.. methods. Rat lenses were cultured in media containing 10 μM TPP+ and a tracer level of 3H-TPP+ for various times. 3H-TPP+ levels in whole lenses or dissected portions of lenses were determined by liquid scintillation counting. Ionophores, transport inhibitors, and neurotransmitters were also added to investigate their effects on TPP+ uptake.. results. Incubation of lenses in low-K+ balanced salt solution and TC-199 medium, containing physiological concentrations of Na+ and K+, led to a biphasic accumulation of TPP+ in the lens that approached equilibrium by 12 to 16 hours of culture. The TPP+ equilibrated within 1 hour in the epithelium but penetrated more slowly into ...

Instant membrane resealing importantly contributes to the functional and structural integrity of the endothelial cells (ECs) that are exposed to various physical and chemical stimuli in blood stream. The present study was designed to explore the molecular mechanisms mediating this endothelial membrane resealing with a focus on the role of lipid rafts (LR) clustering. Using high energy Laser gun, a tiny hole was made in cultured EC bathed with FM1-43, and the rapid entry of this FM1-43 to produce fluorescence was used to measure membrane resealing. We demonstrated that ECs exhibited a Ca2+-dependent instant membrane resealing, as shown by a significant reduction of fluorescence appearance within these cells compared to ECs bathed with Ca2+ free solution. This Ca2+-dependent instant membrane resealing was also observed in ECs up stimulation of Lactobacillus casei cell wall fragments (LCWE), which was commonly used to produce arteritis. When ECs were pretreated with LRs clustering stimulators such ...

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PURPOSE To establish an 'electrical fingerprint' for the gap junction channels between mammalian lens epithelial cells. METHODS The double whole cell patch clamp technique was applied to isolated cell pairs obtained from mouse lens epithelium and a continuous cell line of lens epithelial cells derived from the sheep lens (SLE 2.1). RESULTS The junctional conductance in mouse lens epithelial cells and in cultured SLE 2.1 cells was found to be moderately voltage dependent. SLE 2.1 cells were analyzed in more detail. The voltage dependence could be described by a Boltzmann distribution with Vo = +/- 63.1 mV and Gmin = 0.34. In cell pairs that exhibited spontaneously low junctional conductance, single channel events could be distinguished. Single gap junction channel currents had a linear current-voltage relationship. A frequency histogram of single channel conductances from eight cell pairs had three major peaks of 35, 60 and 97 pS. CONCLUSION The electrical properties of gap junction channels

Abstract: Using a model of hemorrhagic shock, the possibility of protection byCu,Zn-superoxide dismutase (SOD) of the phospholipid bilayer of plasma membranes ofhepatocytes and adipocytes as well as of the blood lipoproteins was studied. SOD (5mg/kg), injected 30 min after the onset of bleeding, efficiently prevented changes in thephospholipid bilayer of hepatocytic plasma membranes in cats. Simultaneous injection ofSOD partly restored the concentration of different classes of phospholipids in plasmamembranes of mesenterial fatty tissue adipocytes altered by shock. When incorporated intoliposomes, SOD exerted a weaker corrective effect on the phospholipid composition ofhepatocytic plasma membranes in animals with hemorrhagic shock and simultaneously produceda membrane-stabilizing effect on adipocytes. In contrast to pure SOD (which had no effecton the lipoprotein composition of the blood in animals with hemorrhagic shock),SOD-containing liposomes decreased the amount of chylomicrons and very low ...

White bass (Roccus chrysops) retinal horizontal cells possess two types of voltage-activated calcium currents which have recently been characterized with regard to their voltage dependence and pharmacology (Sullivan, J., and E. M. Lasater. 1992. Journal of General Physiology. 99:85-107). A low voltage-activated transient current was identified which resembles the T-type calcium current described in a number of other preparations, along with a sustained high threshold, long-lasting calcium current that resembles the L-type calcium current. Here we report on the modulation of horizontal cell calcium channels by dopamine. Under whole-cell voltage clamp conditions favoring the expression of both calcium currents, dopamine had opposing actions on the two types of voltage-sensitive calcium currents in the same cone-type horizontal cell. The L-type calcium current was significantly potentiated by dopamine while the T-type current was simultaneously reduced. Dopamine had no effect on calcium currents in ...

Polyunsaturated fatty acids (PUFA) have strong effects on hibernation and daily torpor. Increased dietary uptake of PUFA of the n-6 class, particularly of Linoleic acid (LA, C18:2 n-6) lengthens torpor bout duration and enables animals to reach lower body temperatures (Tb) and metabolic rates. As previously hypothesized, this well-known influence of PUFA may be mediated via effects of the membrane fatty acid composition on sarcoplasmic reticulum (SR) Ca2+−ATPase 2a (SERCA) in the heart of hibernators. We tested the hypotheses that high proportions of n-6 PUFA in general, or specifically high proportions of LA (C18:2 n-6) in SR phospholipids (PL) should be associated with increased cardiac SERCA activity, and should allow animals to reach lower minimum Tb in torpor. We measured activity of SERCA from hearts of hibernating and non-hibernating Syrian hamsters (Mesocricetus auratus) in vitro at 35°C. Further, we determined the PL fatty acid composition of the SR membrane of these hearts. We found that

Several conflicting models have been used to characterize the gating behavior of the cardiac delayed rectifier. In this study, whole-cell delayed rectifier currents were measured in voltage-clamped guinea pig ventricular myocytes, and a minimal model which reproduced the observed kinetic behavior was identified. First, whole-cell potassium currents between -10 and +70 mV were recorded using external solutions designed to eliminate Na and Ca currents and two components of time-dependent outward current were found. One component was a La3(+)-sensitive current which inactivated and resembled the transient outward current described in other cell types; single-channel observations confirmed the presence of a transient outward current in these guinea pig ventricular cells (gamma = 9.9 pS, [K]o = 4.5 mM). Analysis of envelopes of tail amplitudes demonstrated that this component was absent in solutions containing 30-100 microM La3+. The remaining time-dependent current, IK, activated with a sigmoidal ...

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Paramecium, a unicellular ciliate, can be attracted by various chemical stimuli. Chemoattractants such as glutamate, folate, cAMP, and acetate activate different receptor mediated signal transduction pathways. The final event in these signal transductions is a hyperpolarization of membrane potential, which makes Paramecium swim smoothly and fast. There is evidence that the effecter of this hyperpolarization is the plasma membrane calcium ATPase (PMCA), that when activated, expels Ca2+ from the cell. In Paramecium three PMCA isoforms, named PMCA2, 3, and 4, have been cloned. PMCA2 is associated with lipid rafts, which is demonstrated by its resistance to cold detergent solubilization and distribution in sucrose density gradients in ultracentrifugation. PMCA3 and 4 are not associated with lipid rafts. On the cell surface, PMCAs are localized to the bases of cilia. Sterol-depletion by methyl-ß-cyclodextrin (MßCD) treatment disrupts the distribution of PMCA2 in sucrose density gradients and ciliary base

AS07 239, anti-Toc159, translocon at the outer envelope membrane of chloroplasts, Toc-complex, TOC-complex, GTPase, Chloroplast protein import component Toc159, Toc 159 antibody, Q9LKR1Toc159 is located in the outer chloroplast membrane and part of of the

Imaging single-channel Ca21 signals by total internal reflection fluorescence microscopy. (A) Schematic of the TIRFM imaging system. The 488-nm beam from an argon ion laser (50 mW) passes through a 53 beam expander (BE) and is focused by a lens (FL; f ¼ 150 mm) via a dichroic mirror (DM)to a spot at the back focal plane of the microscope objective lens (Olympus TIRFM 603, oil immersion, NA ¼ 1.45). The focusing lens is mounted on a micrometer-driven translation stage, so that the laser beam can be adjusted to enter the periphery of the objective aperture so as to achieve total internal reflection at the interface between the cover glass and the aqueous bathing medium. An adjustable rectangular knife-blade aperture (A) located at a conjugate image plane defines the field of excitation. Fluorescence excited in the specimen by the evanescent wave is collected by the same objective, passes through the dichroic mirror and a barrier filter (BF) blocking the laser wavelength, and is imaged by an ...

The cardiac transient outward potassium current (referred to as Ito1 or Ito ) is one of the ion currents across the cell membrane of heart muscle cells. It is the main contributing current during the repolarizing phase 1 of the cardiac action potential. It is a result of the movement of positively charged potassium (K+) ions from the intracellular to the extracellular space. Ito1 is complemented with Ito2 resulting from Cl− ions to form the transient outward current Ito. Ito1 is rapidly activated and deactivated. It is activated after the fast increase of the membrane potential following the phase 0 of the cardiac action potential. Once activated, (K+) ions from inside the cells flow to the extracellular space. This outward flow of positively charged ions constitutes the Ito1 and causes the transmembrane voltage to decrease.This decrease of the transmembrane potential is known as repolarization. Ito1 is then quickly deactivated, stopping the repolarization and ending the phase 1 of the action ...

This study aimed to investigate effects of citrus flavanones naringenin (NAR) and hesperetin (HES) on liver antioxidant status and membrane phospholipid composition in 24-month-old rats. NAR and HES (15 mg/kg) were administrated orally to male Wistar rats, once per day, for 4 weeks. Control group received either vehicle (sunflower oil) or remained intact. The results showed decreased (p , 0.05) activity of antioxidant enzymes (AOE), specifically catalase (CAT), superoxide dismutase (SOD) 1 and glutathione reductase (GR) in the liver of intact control old-aged rats in comparison to young intact controls. Flavanone administration to old-aged males increased (p , 0.05) examined AOE activities in comparison to vehicle-administered animals. Namely, NAR was more potent in comparison to HES regarding the increase (p , 0.05) in activities of examined antioxidant enzymes (SOD 1 and 2, glutathione peroxidase-GPx and GR) and the liver glutathione (GSH), while HES elevated (p , 0.05) only activity of CAT ...

TY - JOUR. T1 - The mitochondrial permeability transition from in vitro artifact to disease target. AU - Bernardi, Paolo. AU - Krauskopf, Alexandra. AU - Basso, Emy. AU - Petronilli, Valeria. AU - Blalchy-Dyson, Elizabeth. AU - Di Lisa, Fabio. AU - Forte, Michael. PY - 2006/5. Y1 - 2006/5. N2 - The mitochondrial permeability transition pore is a high conductance channel whose opening leads to an increase of mitochondrial inner membrane permeability to solutes with molecular masses up to ≈1500 Da. In this review we trace the rise of the permeability transition pore from the status of in vitro artifact to that of effector mechanism of cell death. We then cover recent results based on genetic inactivation of putative permeability transition pore components, and discuss their meaning for our understanding of pore structure. Finally, we discuss evidence indicating that the permeability transition pore plays a role in pathophysiology, with specific emphasis on in vivo models of disease.. AB - The ...

TY - JOUR. T1 - Effect of different calcium channel blockers on inhibitory junction potentials and slow waves in porcine ileum. AU - Borderies, J. R.. AU - Goñalons, E.. AU - Angel, F.. AU - Vergara, P.. AU - Jiménez, Marcel. PY - 1997/2/14. Y1 - 1997/2/14. N2 - The effect of several calcium channel blockers was evaluated: (i) on spontaneous electrical and mechanical activities and (ii) on the response to electrical field stimulation. The study was carried out on whole-thickness preparation of porcine ileum. Glass microelectrodes were used to record membrane potential from smooth muscle cells. Resting membrane potential was -60 ± 2 mV (n = 18) and preparations generated spontaneous slow waves. Electrical field stimulation (EFS) was applied using different parameters. The amplitude and duration of inhibitory junction potentials (IJPs) increased with EFS strength. IJPs were abolished by tetrodotoxin (1 μM). Nifedipine (1 μM) did not modify the amplitude or duration of IJPs. The frequency of ...

Monoclonal antibodies were used as cytochemical markers to study surface interactions between endosymbiotic Rhizobium bacteroids from pea root nodules and the encircling peribacteroid membranes, which are of plant origin. Monoclonal antibodies that react with Rhizobium lipopolysaccharide (LPS) or with a plant membrane glycoprotein were used as markers for material from the bacteroid outer membrane or the peribacteroid membrane, respectively. Membrane-enclosed bacteroids were isolated from nodule homogenates by sucrose gradient centrifugation, and the encircling peribacteroid membrane was released by mild osmotic shock treatment. Using an immunochemical technique (sandwich ELISA), it was shown that 1-5% of the LPS antigen released into the peribacteroid fraction by mild osmotic shock treatment was physically associated with peribacteroid membrane through a detergent-sensitive linkage. This association could be visualized when freshly prepared peribacteroid material was immobilized on gold grids ...

TY - JOUR. T1 - Mitochondria-associated membrane collapse is a common pathomechanism in SIGMAR1- and SOD1-linked ALS. AU - Watanabe, Seiji. AU - Ilieva, Hristelina. AU - Tamada, Hiromi. AU - Nomura, Hanae. AU - Komine, Okiru. AU - Endo, Fumito. AU - Jin, Shijie. AU - Mancias, Pedro. AU - Kiyama, Hiroshi. AU - Yamanaka, Koji. N1 - Funding Information: We thank the Support Unit for Animal Resource Development and Biomaterial Analysis in RIKEN BSI Research Resource Center, Center for Gene Research, and Center for Animal Research and Education, Nagoya University for recovery of Sig1R. PY - 2016/12/1. Y1 - 2016/12/1. N2 - A homozygous mutation in the gene for sigma 1 receptor (Sig1R) is a cause of inherited juvenile amyotrophic lateral sclerosis (ALS16). Sig1R localizes to the mitochondria-associated membrane (MAM), which is an interface of mitochondria and endoplasmic reticulum. However, the role of the MAM in ALS is not fully elucidated. Here, we identified a homozygous p.L95fs mutation of Sig1R as ...

Ever since the emergence of the hypothesis that linked the aetiology of schizophrenia with abnormal membrane phospholipids composition, an increasing number of evidences have suggested reduced membrane polyunsaturated fatty acids in patients with schizophrenia. This has led to a conduct of several studies to evaluate the efficacy of omega-3 fatty acid supplement in the modification of membrane phospholipids and treatment of schizophrenia. The two main omega-3 fatty acid classes, EPA and DHA, play a vital role in membranes. This project work reviews omega-3 fatty acid studies and summarizes their outcomes. Eight original articles (nine studies) were reviewed. Six out of nine studies measured RBC membrane fatty acids levels and all six studies reported a significant increase in EPA after EPA supplement. Two studies reported increased DHA post omega-3 fatty acid and DHA supplement, respectively. One study observed a dose-dependent increment in DHA after EPA supplement. Improved symptoms were ...

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Probably participates in establishing action potential waveform and excitability of neuronal and muscle tissues. Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium. Can be blocked by extracellular barium or cesium.

TY - JOUR. T1 - Partitioning of proteins into plasma membrane microdomains. Clustering of mutant influenza virus hemagglutinins into coated pits depends on the strength of the internalization signal. AU - Fire, Ella. AU - Brown, Claire M.. AU - Roth, Michael G.. AU - Henis, Yoav I.. AU - Petersen, Nils O.. PY - 1997/11/21. Y1 - 1997/11/21. N2 - Internalization of membrane proteins involves their recruitment into plasma membrane clathrin-coated pits, with which they are thought to interact by binding to AP-2 adaptor protein complexes. To investigate the interactions of membrane proteins with coated pits at the cell surface, we applied image correlation spectroscopy to measure directly and quantitatively the clustering of influenza hemagglutinin (HA) protein mutants carrying specific cytoplasmic internalization signals. The HA system enables direct comparison between isolated internalization signals, because HA itself is excluded from coated pits. The studies presented here provide, for the first ...

We report the use of a high-refractive-index aplanatic solid immersion lens (ASIL) in total internal reflection fluorescence (TIRF) microscopy. This new solid immersion total internal reflection fluorescence (SITIRF) microscopy allows highly confined surface imaging with a significantly reduced imaging depth compared with conventional TIRF microscopy. We explore the application of a high refractive index, low optical dispersion material zirconium dioxide in the SITIRF microscope and also introduce a novel system design which enables the SITIRF microscope to work either in the epi-fluorescence or TIRF modes with variable illumination angles. We use both synthetic and biological samples to demonstrate that the imaging depth in the SITIRF microscope can be confined to a few tens of nanometers. SITIRF microscopy has the advantages of performing highly selective imaging and high-resolution high-contrast imaging. Potential applications in biological imaging and future developments of SITIRF microscopy ...

This gene encodes a member of the evolutionarily conserved TIMM (translocase of inner mitochondrial membrane) family of proteins that function as chaperones in the import of proteins from the cytoplasm into the mitochondrial inner membrane. Proteins of this family play a role in collecting substrate proteins from the translocase of the outer mitochondrial membrane (TOM) complex and delivering them to either the sorting and assembly machinery in the outer mitochondrial membrane (SAM) complex or the TIMM22 complex in the inner mitochondrial membrane. The encoded protein and the translocase of mitochondrial inner membrane 8a protein form a 70 kDa complex in the intermembrane space. [provided by RefSeq, Jul 2013 ...

The plasmids pcDNA3-PMP34myc and pcDNA3-PEX13myc have been described (Liu et al. 1999; Sacksteder et al. 2000). All PMP34 and PEX13 truncation mutants were generated by amplifying the desired fragment using primers that append the sequence 5′-GGTACCATG-3′ (encoding an Asp718 site and a start codon) at the 5′ end of the fragment, and the sequence 5′-GGATCC-3′ (encoding a BamHI site) at the 3′ end of the fragment, using the published sequences as a guide (Bjorkman et al. 1998; Wylin et al. 1999). PCR products were then digested with Asp718 and BamHI and cloned upstream of, and in frame with, either 3 sequential c-myc epitopes in the plasmid pcDNA3/3xmyc (Geisbrecht et al. 1998) or 13 sequential c-myc epitopes in the plasmid pcDNA3/13xmyc. The plasmid pNHA is designed to append a 17-amino acid hemagglutinin (HA) epitope tag, NH3-MAYPYDVPDYAGGSGSS-COOH, to the NH2 terminus of a protein. The expression vector pNHA-PTE1 was constructed by inserting a BamHI/XbaI fragment of pNmyc-PTE1 ...

The function of any given biological membrane is determined largely by the specific set of integral membrane proteins embedded in it, and the peripheral membrane proteins attached to the membrane surface. The activity of these proteins, in turn, can be modulated by the phospholipid composition of the membrane. The reconstitution of membrane proteins into a model membrane allows investigation of individual features and activities of a given cell membrane component. However, the activity of membrane proteins is often difficult to sustain following reconstitution, since the composition of the model phospholipid bilayer differs from that of the native cell membrane. This review will discuss the reconstitution of membrane protein activities in four different types of model membrane - monolayers, supported lipid bilayers, liposomes and nanodiscs, comparing their advantages in membrane protein reconstitution. Variation in the surrounding model environments for these four different types of membrane layer can

TY - JOUR. T1 - Membrane specializations of dentritic spines and glia in the weaver mouse cerebellum. T2 - A freeze-fracture study. AU - Hanna, Robert B.. AU - Hirano, Asao. AU - Pappas, George D.. PY - 1976/3/1. Y1 - 1976/3/1. N2 - Electron microscopy of thin-sectioned and freeze-fractured preparations of the cerebellum of the weaver mouse indicates that the dendritic spines are morphologically identical to those of their normal littermates. The weaver dendritic spines have been characterized as "unattached" since the synaptic input from the parallel fibers is absent (8-10). The entire region around the dendritic spines is taken up by astrocytic processes in the weaver. The outer fracture face of a normal dendritic spine contains aggregations of 10-nm wide particles in the immediate postsynaptic region. Similar particle aggregations occur in the unattached spines of the weaver. Freeze-fracture preparations reveal rectilinear arrays of particles, having a 7-nm center-to-center distance in the ...

BISAC: SCI017000. This book presents an overview of membrane organization and lipid rafts in the cell and artificial membranes. The topics analyzed in this book cover a broad spectrum of functions played by lipid rafts in membrane organization within the cell and artificial membranes, and presents new information in this area of research. The topics analyzed include: fluid-mosaic cell membrane structure from cellular control and domains to extracellular vesicles; lipid rafts in binary lipid/cholesterol membranes; membrane assembly and lipid rafts in the cell and artificial membranes; the effect of lipid peroxidation; drugs, delivery systems and membrane organization in model and cell membranes; role of sphingomyelin on membrane domain formation and its influence in protein interaction focusing on the nanometer scale; lipid rafts and cell adhesion; mutual modulators of cell signaling; and finally, roles of glycosphingolipids in the regulation of the membrane organization and cell signaling in ...

Nodaviridae is a family of non-enveloped isometric viruses with bipartite positive-sense RNA genomes. The Nodaviridae family consists of two genera: alpha- and beta-nodavirus. Alphanodaviruses usually infect insect cells. Some commercially available insect cell lines have been latently infected by Alphanodaviruses. A non-enveloped small virus of approximately 30 nm in diameter was discovered co-existing with a recombinant Helicoverpa armigera single nucleopolyhedrovirus (Hear NPV) in Hz-AM1 cells. Genome sequencing and phylogenetic assays indicate that this novel virus belongs to the genus of alphanodavirus in the family Nodaviridae and was designated HzNV. HzNV possesses a RNA genome that contains two segments. RNA1 is 3038 nt long and encodes a 110 kDa viral protein termed protein A. The 1404 nt long RNA2 encodes a 44 kDa protein, which exhibits a high homology with coat protein precursors of other alphanodaviruses. HzNV virions were located in the cytoplasm, in association with cytoplasmic membrane

We report a methodology for the isolation of peroxisome membranes from the yeast Candida tropicalis pK233 grown on oleic acid, and the characterization of the polypeptide and lipid compositions of these membranes. Peroxisomes purified in either sucrose or Nycodenz gradients are treated with Tris-HCl (pH 8.5) and then with sodium carbonate (pH 11.5) to yield a final peroxisome membrane preparation (hereafter called 'peroxisome membranes'). Electron microscopy revealed peroxisome membranes that are approximately 8.1 nm thick, have a typical trilaminar appearance, and form either flattened sheets or whorled structures. Peroxisome membranes contain 3.1% and 2.2% of the total protein of sucrose- and Nycodenz-gradient-purified peroxisomes, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed three predominant polypeptide bands of 34 (PMP 34), 29 (PMP 29), and 24 (PMP 24) × 10(3) Mr in peroxisome membranes. Immunoblotting with an antiserum to PMP 24 showed that PMP ...

Global Breather Membrane Market Professional Survey Report 2018 1 Industry Overview of Breather Membrane 1.1 Definition and Specifications of Breather Membrane 1.1.1 Definition of Breather Membrane 1.1.2 Specifications of Breather Membrane 1.2 Classification of Breather Membrane 1.2.1 Waterproofing Membrane 1.2.2 Metallic Membrane 1.2.3 Other 1.3 Applications of Breather Membrane 1.3.1 Roofing 1.3.2 Wall 1.3.3 Other 1.4 Market Segment by Regions 1.4.1 North America 1.4.2 Europe 1.4.3 China 1.4.4 Japan 1.4.5 Southeast Asia 1.4.6 India 2 Manufacturing Cost Structure Analysis of Breather Membrane 2.1 Raw Material and Suppliers 2.2 Manufacturing Cost Structure Analysis of Breather Membrane 2.3 Manufacturing Process Analysis of Breather Membrane 2.4 Industry Chain Structure of Breather Membrane 3 Technical Data and Manufacturing Plants Analysis of Breather Membrane 3.1 Capacity and Commercial Production Date of Global Breather Membrane Major Manufacturers in 2017 3.2 Manufacturing Plants Distribution ...

Exp Gerontol. 2007 Nov;42(11):1053-62. Comparative Study; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't

We have investigated the role of the protein ubiquitous mitochondrial creatine kinase (uMtCK) in the formation and stabilization of inner and outer membrane contact sites. Using liver mitochondria isolated from transgenic mice, which, unlike control animals, express uMtCK in the liver, we found that the enzyme was associated with the mitochondrial membranes and, in addition, was located in membrane-coated matrix inclusions. In mitochondria isolated from uMtCK transgenic mice, the number of contact sites increased 3-fold compared with that observed in control mitochondria. Furthermore, uMtCK-containing mitochondria were more resistant to detergent-induced lysis than wild-type mitochondria. We conclude that octameric uMtCK induces the formation of mitochondrial contact sites, leading to membrane cross-linking and to an increased stability of the mitochondrial membrane architecture.. ...

SUMMARY: Modifications occurring in the plasma membrane and their relationship to newly synthesized microfibrils were examined in regenerating protoplasts of Candida albicans by freeze-fracture electron microscopy. Freshly prepared protoplasts showed no residual wall material, and long invaginations covered the surface of the plasma membrane. Analysis of the external face (E-face) of the plasma membrane showed a significant decrease in the number of intramembranous particles (IMP) in comparison with the original cells. After 40 min incubation in regeneration medium, newly synthesized microfibrils which seemed to originate from protrusions in the plasma membrane were observed. The plasma membrane showed important modifications with respect to IMP. After 3 h 45 min, the cells were covered by an abnormal wall which showed isolated fibrils partially embedded in the matrix material. The plasma membrane of these partially regenerated protoplasts was similar to that of original cells. After 8 h, regeneration

TY - JOUR. T1 - Modulation of forskolin binding to rat brain membranes. AU - Seamon, K. B.. AU - Vaillancourt, Richard. AU - Daly, J. W.. PY - 1985. Y1 - 1985. N2 - High affinity binding sites for [3H]forskolin have been identified in rat brain membranes. These sites have a K(d) of 15 nM and a B(max) of about 200 fmol/mg protein. The binding of [3H]forskolin to those high affinity sites in rat brain membranes is increased about two-fold by addition of MgCl2 or MnCl2. Smaller increases are observed in the presence of calcium, sodium, or potassium. The binding of [3H]forskolin is also increased in the presence of NaF or GppNHp, agents that are known to activate adenylate cyclase through the stimulatory guanine nucleotide regulatory protein (N(s)). The increase in [3H]forskolin binding in the presence of NaF or GppNHp is due to an increase in the number of binding sites with no change in the apparent K(d) for the binding sites. The NaF- and GppNHp-stimulated binding requires the presence of ...

A sweep membrane separator includes a membrane that is selectively permeable to a selected gas, the membrane including a retentate side and a permeate side. A mixed gas stream including the selected gas enters the sweep membrane separator and contacts the retentate side of the membrane. At least part of the selected gas separates from the mixed gas stream and passes through the membrane to the permeate side of the membrane. The mixed gas stream, minus the separated gas, exits the sweep membrane separator. A sweep gas at high pressure enters the sweep membrane separator and sweeps the selected gas from the permeate side of the membrane. A mixture of the sweep gas and the selected gas exits the sweep membrane separator at high pressure. The sweep membrane separator thereby separates the selected gas from the gas mixture and pressurizes the selected gas.

Membrane environment and fluidity can modulate the dynamics and interactions of membrane proteins and can thereby strongly influence the function of cells and organisms in general. In this work, we demonstrate that trans-cis isomerization of lipophilic dyes is a useful parameter to monitor packaging and fluidity of biomembranes. Fluorescence fluctuations, generated by trans-cis isomerization of the thiocarbocyanine dye Merocyanine 540 (MC540), were first analyzed by fluorescence correlation spectroscopy (FCS) in different alcohol solutions. Similar isomerization kinetics of MC540 in lipid vesicles could then also be monitored, and the influence of lipid polarity, membrane curvature, and cholesterol content was investigated. While no influence of membrane curvature and lipid polarity could be observed, a clear decrease in the isomerization rates could be observed with increasing cholesterol contents in the vesicle membranes. Finally, procedures to spatially map photoinduced and thermal ...

The overexpression and purification of membrane proteins is a bottleneck in biotechnology and structural biology. E. coli remains the host of choice for membrane protein production. To date, most of the efforts have focused on genetically tuning of expression systems and shaping membrane composition to improve membrane protein production remained largely unexplored. In E. coli C41(DE3) strain, we deleted two transporters involved in fatty acid metabolism (OmpF and AcrB), which are also recalcitrant contaminants crystallizing even at low concentration. Engineered expression hosts presented an enhanced fitness and improved folding of target membrane proteins, which correlated with an altered membrane fluidity. We demonstrated the scope of this approach by overproducing several membrane proteins (4 different ABC transporters, YidC and SecYEG). In summary, E. coli membrane engineering unprecedentedly increases the quality and yield of membrane protein preparations. This strategy opens a new field for

Physiology and structure of cell membrane depend on the proportion of lipids, proteins and carbohydrates. They change according to the cell type and membrane location. For example, plasma membrane of erythrocytes contain 50 % of lipids, 40 % of proteins and 10 % of carbohydrates. A similar composition is found in most of the plasma membranes of other cell types, with some exceptions. Myelin, cell membrane of glial cells that wraps axons, is composed of 80 % of lipids and 20 % of proteins, and almost no carbohydrates. Intracellular membranes usually show a higher proportion of proteins than plasma membrane. A remarkable example is the inner mitochondrial membrane, where proteins are up to 80 %. Furthermore, lipids, proteins, and carbohydrates are diverse, and membranes do not only differ in the proportion of these three molecular groups, but also in the different types of lipids, proteins, and carbohydrates that are present. Moreover, as mentioned above, membranes are continuously recycled, and ...

The integration of membranes in microfluidics has attracted significant interest over the last two decades to offer precise mass transport for filtration, extraction, and gas-liquid exchange.1,2 One of the most important attributes to the mass transport of membranes for selective subjects is semi-permeability. The transport is based on a difference in chemical potential between the two sides of a semi-permeable membrane that allows selective subjects to diffuse through.3 Since the membrane porosity governs the transport, it is highly desired that the porosity can be actively tuned and customized to enhance the implementation of integrated membranes. Many approaches have been employed to integrate membranes into microfluidics, including direct incorporation of commercially available membranes, membrane preparation as part of the chip fabrication process, in situ preparation of membranes, and the direct use of the membrane properties of a bulk chip material.3 Among them, the in situ biofabrication ...