REPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2009
X Sun
Contents In several mammalian species, the configuration of germinal vesicle (GV) chromatin correlates with the developmental competence of oocytes. Yet, no study has been published on the configuration of GV chromatin in ferret, nor is it known whether a specific configuration predicts meiotic competence in this species, in spite of the potential importance of ferret cloning to the study of human disease and to species conservation efforts. Here, we report on an analysis of the chromatin configuration in ferret GV oocytes and on how they correlate with meiotic development. Three distinct configurations were identified based on the degree of chromatin condensation: (1) fibrillar chromatin (FC), featuring strands of intertwined chromatin occupying most of the visible GV region; (2) intermediate condensed chromatin (ICC), characterized by dense, irregular chromatin masses throughout the GV; and (3) condensed chromatin (CC), which is highly compact and centered around the nucleolus. We also found that chromatin configuration was related to the extent of association with cumulus cells in cumulus,oocyte complexes; CC-configured oocytes were most often surrounded by a compact cumulus layer and also a compact corona but FC-configured oocytes were associated with neither. In addition, increasing chromatin condensation corresponded to an increase in oocyte diameter. Finally, following in vitro culture, significantly more CC-configured oocytes underwent maturation to meiotic metaphase II than did FC- or ICC-configured oocytes. We conclude that, in ferret, chromatin condensation is related to the sequential achievement of meiotic competencies during oocyte growth and differentiation, and thus can be used as a predictor of competence. [source]

Membrane associated nonmuscle myosin II functions as a motor for actin-based vesicle transport in clam oocyte extracts

CYTOSKELETON, Issue 10 2007
Ana S. DePina
Abstract Nonmuscle myosin II (Myo2) has been shown to associate with membranes of the trans -Golgi network and to be involved in Golgi to ER retrograde protein transport. Here, we provide evidence that Myo2 not only associates with membranes but functions to transport vesicles on actin filaments (AFs). We used extracts from unactivated clam oocytes for these studies. AFs assembled spontaneously in these extracts and myosin-dependent vesicle transport was observed upon activation. In addition, actin bundles formed and moved relative to each other at an average speed of ,0.30 ,m/s. Motion analysis revealed that vesicles moved on the spontaneously assembled AFs at speeds greater than 1 ,m/s. The motor on these vesicles was identified as a member of the nonmuscle Myo2 family based on sequence determination by Edman chemistry. Vesicles in these extracts were purified by sucrose gradient centrifugation and movement was reconstituted in vitro using skeletal muscle actin coated coverslips. When peripheral membrane proteins of vesicles including Myo2 were removed by salt stripping or when extracts were treated with an antibody specific to clam oocyte nonmuscle Myo2, vesicle movement was inhibited. Blebbistatin, a Myo2 specific inhibitor, also blocked vesicle movement. Myo2 light chain kinase activity was found to be essential for vesicle movement and sliding of actin bundles. Together, our data provide direct evidence that nonmuscle Myo2 is involved in actin-dependent vesicle transport in clam oocytes. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source]

Direct Spectroscopic Evidence that the Photochemical Outcome of Flutamide in a Protein Environment is Tuned by Modification of the Molecular Geometry: A Comparison with the Photobehavior in Cyclodextrin and Vesicles

HELVETICA CHIMICA ACTA, Issue 2 2003
Salvatore Sortino
The photoreactivity of the phototoxic anticancer drug flutamide (FM) in the presence of bovine serum albumin (BSA) has been investigated. The presence of BSA induces a remarkable modification of the photochemical outcome of the drug with respect to that observed in aqueous solution. Induced circular dichroism (ICD) measurements combined with theoretical calculations provide strong evidence that the new photochemical scenario is tuned by changes of the molecular geometry of FM when incorporated in the protein microenvironment. This behavior presents close analogies to that found in the presence of either cyclodextrin or phospholipid vesicles, chosen as models for biological systems, and delineates a quite general photochemical picture that can be useful for a more appropriate understanding of the adverse phototoxic effects induced by this drug. [source]

An Aqueous Emulsion Route to Synthesize Mesoporous Carbon Vesicles and Their Nanocomposites

ADVANCED MATERIALS, Issue 7 2010
Dong Gu
Onionlike mesoporous carbon and carbon,silica nanocomposites with multilayer vesicle structures can be synthesized by an organic,inorganic co-assembly method under hydrothermal conditions in an aqueous emulsion solution (see figure). The nanocomposite vesicles have ordered lamellar mesostructures with about 3,9 layers and carbon pillars are located between the neighboring shells. [source]

Nanotopographic Carbon Nanotube Thin-Film Substrate Freezes Lateral Motion of Secretory Vesicles

ADVANCED MATERIALS, Issue 7 2009
Jing Zhang
Thin-film carbon-nanotube networks can interface with living neuroendocrine PC12 cells and support their growth and proliferation. Interestingly, as revealed by total-internal-reflection fluorescence microscopy, the nanoroughness created by the carbon-nanotube net physically deforms the 5,nm thick cell membrane with high local curvature, and significantly impedes the lateral motion of subplasmalemmal secretory vesicles. [source]

Vesicles as reactors of nanoparticles: an anomalous small-angle X-ray scattering study of the domains rich in copper ions

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2007
Attila Bóta
The formation of copper hydroxide and copper oxide particles in the gaps among the stacks of multilamellar vesicles is described, illustrating a new pathway in the preparation of nanometre-scale particles. The in situ structural characterization of both the solid particles and the vesicles as a reaction medium was performed in the initial and final states of the process by using anomalous small-angle X-ray scattering (ASAXS) and freeze-fracture methods. The ASAXS method provides a description of the particle-size distribution of the copper nanoparticles, in spite of the fact that they are present in low concentration. This method allows the particle formation and growth to be monitored throughout the whole time range of the synthesis. [source]

Functional Differences Between Growth Plate Apoptotic Bodies and Matrix Vesicles,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2003
Thorsten Kirsch
Abstract Mineralization often occurs in areas of apoptotic changes. Our findings indicate that physiological mineralization is mediated by matrix vesicles. These matrix vesicles use mechanisms to induce mineralization that are different from the mechanisms used by apoptotic bodies released from apoptotic cells. Therefore, different therapeutic approaches must be chosen to inhibit pathological mineralization depending on the mechanism of mineralization (matrix vesicles versus apoptotic bodies). Introduction: Physiological mineralization in growth plate cartilage is restricted to regions of terminally differentiated and apoptotic chondrocytes. Pathological mineralization of tissues also often occurs in areas of apoptosis. We addressed the question of whether apoptotic changes control mineralization events or whether both events are regulated independently. Methods: To induce mineralization, we treated growth plate chondrocytes with retinoic acid (RA); apoptosis in these cells was induced by treatment with staurosporine, anti-Fas, or TNF,. The degrees of mineralization and apoptosis were determined, and the structure and function of matrix vesicles and apoptotic bodies were compared. Results: Release of matrix vesicles and mineralization in vivo in the growth plate occurs earlier than do apoptotic changes. To determine the functional relationship between apoptotic bodies and matrix vesicles, growth plate chondrocytes were treated with RA to induce matrix vesicle release and with staurosporine to induce release of apoptotic bodies. After 3 days, approximately 90% of staurosporine-treated chondrocytes were apoptotic, whereas only 2,4 % of RA-treated cells showed apoptotic changes. RA- and staurosporine-treated chondrocyte cultures were mineralized after 3 days. Matrix vesicles isolated from RA-treated cultures and apoptotic bodies isolated from staurosporine-treated cultures were associated with calcium and phosphate. However, matrix vesicles were bigger than apoptotic bodies. Furthermore, matrix vesicles but not apoptotic bodies contained alkaline phosphatase and Ca2+ channel-forming annexins II, V, and VI. Consequently, matrix vesicles but not apoptotic bodies were able to take up Ca2+ and form the first mineral phase inside their lumen. Mineralization of RA-treated cultures was inhibited by antibodies specific for annexin V but not mineralization of staurosporine-treated cultures. Conclusion: Physiological mineralization of growth plate chondrocytes is initiated by specialized matrix vesicles and requires alkaline phosphatase and annexins. In contrast, mineral formation mediated by apoptotic bodies occurs by a default mechanism and does not require alkaline phosphatase and annexins. [source]

MHC Class II Vesicles (CIIV) within immature dendritic cells

JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 2 2004
E. Radu
No abstract is available for this article. [source]

Analysis of several fluorescent detector molecules for protein microarray use

LUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 1 2003
Rick Wiese
Abstract The utility of several streptavidin-linked fluorescent detector molecules was evaluated on two protein microarray platforms. Tested detector molecules included: Alexa Fluor 546; R-phycoerythrin (RPE), orange fluospheres; Cy3-containing liposomes (Large Unilamellar Vesicles, LUV) labelled with Cy3; and an RPE,antibody complex. The two array architectures tested consisted of an array of murine Fc,biotin and an array of murine IgG (the murine IgG array was probed with a biotinylated rabbit anti-murine IgG). These platforms allowed for the direct comparison of detector utility by detector recognition of array-bound biotin. All of the fluorescent detectors examined demonstrated utility on each of the array platforms. For the Fc,biotin array, detector signal intensity (background adjusted) was as follows: RPE,antibody complex,>,fluospheres,>,RPE,>,liposomes,>,Alexa 546: for the IgG array: RPE/antibody complex,>,RPE,>,fluospheres,>,Alexa546,>,liposomes. The RPE,antibody complex fluoresced 67% and 150% more intensely than the next closest detector molecule for the Fc,biotin and the murine IgG arrays, respectively. A marked increase in background fluorescence (as compared to RPE alone) did not accompany the increase in signal intensity gained through RPE,antibody complex use (a true increase in signal:noise ratio). These results suggest that the RPE,antibody complex is superior to other molecules for fluorescent detection of analytes on protein microarrays. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Hydrogen-Bonded Shape-Persistent Aryl Hydrazide Polymers: Side-Chain-Tuned Formation of Vesicles and Organogels

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 19 2010
Cen Zhou
Abstract A new class of aromatic, hydrazide-based, zigzag polymer has been synthesized using the Yamazaki polymerization conditions. Hydrophobic, hydrophilic or amphiphilic side chains are introduced to the backbones to tune their solubility in organic solvents of different polarities. The side chains form successive, intramolecular, six-membered RO···HN hydrogen bonds, which increase the planarity of the backbones. The new shape-persistent polymers are revealed to self-assemble into vesicles or fibers to gelate organic solvents of different polarities. The polymeric backbones may be regarded as a conceptual extension of the emerging foldamers, which are usually constructed from oligomeric backbones. [source]

Stability and Drug Loading of Spontaneous Vesicles of Comb-Like PEG Derivates

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 5 2007
Xiaolin Li
Abstract A novel comb-like derivative CPEG- g -cholesterol was prepared by the reaction of cholesteryl chloroformate with hydroxyl groups of CPEG. The TEM and SEM results showed that CPEG-cholesterol spontaneously aggregated vesicles with the membrane thickness of 4.27,±,0.48 nm. Compared with the vesicles formed by comb-like PEG (CPEG), the derivation of cholesteryl chloroformate increased the thickness of vesicle membrane and developed corrugations. The hydrophobic doxorubicin (Dox) was added into the solution of CPEG and CPEG- g -cholesterol to test their vesicle stability. The drug-loaded vesicles of CPEG- g -cholesterol still existed but those of CPEG disappeared, which indicated that stability of vesicles was enhanced by the derived cholesteryl chloroformate. The vesicles were further cross-linked by the reaction between divinyl sulfone (DVS) and the hydroxy groups in the side chains of the CPEG and CPEG- g -cholesterol. Both cross-linked vesicles of CPEG and CPEG- g -cholesterol entrapped considerable hydrophobic Dox in the vesicles membrane. The spontaneous vesicles of CPEG- g -cholesterol and the crosslinked vesicles of CPEG and CPEG- g -cholesterol might have great potential as a cargo of the hydrophobic drug. [source]

Synthesis of PEDOT Nanoparticles and Vesicles by Dispersion Polymerization in Alcoholic Media

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 17 2006
Muhammad Mumtaz
Abstract Summary: The synthesis of PEDOT nanoparticles and vesicles by dispersion polymerization in a methanol/water mixture (3/2, v/v) is reported, using either ammonium persulfate or iron(III) p -toluenesulfonate as oxidants and , -EDOT-PEO as a reactive stabilizer. The influence of the oxidant as well as the , -EDOT-PEO molar mass and concentration on the core-shell particle morphology and conductivity properties have been investigated. PEDOT particles with conductivities up to 1.5,×,10,2 S,·,cm,1 have been obtained in high yield. TEM image of PEDOT vesicles prepared using PEO-based stabilizers of 25,000 g,·,mol,1 in water/methanol mixture (2:3 v/v) at room temperature using ammonium persulfate as an oxidant. [source]

A Discrete, Space Variation Model for Studying the Kinetics of Shape Deformation of Vesicles Coupled with Phase Separation

MACROMOLECULAR THEORY AND SIMULATIONS, Issue 5 2006
Jianfeng Li
Abstract Summary: The evolution dynamics of phase separation, coupled with shape deformation of vesicles is described by using dissipative dynamic equations, specifically the time-dependent Ginzburg-Landau (TDGL) equations. In order to improve the numerical stability and thus to efficiently deal with a large deformation of vesicles, a new algorithm, namely the discrete space variation model (DSVM) has been developed for the first time. The algorithm is based on the variation of the discretized free-energy functional, which is constructed in discrete membrane space, in contrast to the commonly used continuous free-energy functional. For the sake of numerical tractability, only the cylindrical vesicles (2D), with two components, are taken into consideration to illustrate the efficiency and validity of new algorithm. The simulation results, based on the DSVM algorithm have been compared with those from both linear analysis and strong segregation theory using the continuous space free-energy functional. It is found that the DSVM algorithm can correctly describe the coupling between the lateral phase-separation on the vesicle membrane and the vesicle shape deformation, both for early and late stages. A flower-like vesicle obtained by DSVM simulation. [source]

Vesicle transport and the cytoskeleton in the unicellular red alga Glaucosphaera vacuolata

PHYCOLOGICAL RESEARCH, Issue 1 2006
Sarah M. Wilson
SUMMARY Vesicles are continually transported from the perinuclear region to the cell's exterior in the unicellular red alga Glaucosphaera vacuolata Korshikov. This phenomenon is recorded here with time-lapse videomicroscopy. The mechanism governing this intracellular motility is unknown but the cytoskeleton is believed to be involved. Microtubules and actin filaments are located in Glaucosphaera using fluorescently conjugated antibodies and FITC-phallicidin, respectively. Microtubules radiate in all planes from the perinuclear region to the periphery whereas actin filaments form rings around migrating vesicles. This pattern of location might indicate that both microtubules and actin filaments are involved in vesicle transport. However, this conclusion is not confirmed directly because the thick mucilaginous wall material seemed to prevent the entry of cytoskeletal inhibitors. A video clip of vesicle movement is available at http://www.cytographics.com/. [source]

Formation and characterization of polymersomes made by a solvent injection method

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2007
M. E. Yildiz
Abstract In this article a solvent injection method is described for vesicle formation using poly(butadiene)- b-poly(acrylic acid) diblock copolymers as the amphiphilic molecules. Vesicles composed of polymer bilayers are commonly referred to as polymersomes. Solvent injection is shown to be a rapid method for polymersome formation suitable to make large volumes of polymersome solution. The method can be manipulated to obtain a wide range of vesicle sizes depending on the polymer concentration and preparation conditions. Polymersome solutions in this study are characterized using dynamic light scattering (DLS), fluorescent microscopy, and electron microscopy. Polymersome sizes range from tens of nanometers to several microns. The membrane thickness of smaller polymersomes is found to lie between 14,20,nm. Larger polymersomes are found to have somewhat thicker membranes. The procedure involves the addition of polymers dissolved in an organic solvent to a stirred aqueous solution. The formation of polymersomes by this method is proposed to be governed by the limited mutual solubility of the two solvents and the simultaneous diffusion of solvent and water out of and in to initially formed organic solvent droplets. Copyright © 2007 John Wiley & Sons, Ltd. [source]

The Origin of Membrane Vesicles in Ram Seminal Plasma

REPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2006
R El-Hajj Ghaoui
Contents The hypothesis tested in this study was that the membrane vesicles present in ram seminal plasma are of testicular origin, rather than being secreted by the accessory sex glands as has been previously reported for a number of species. Membrane vesicles were present in cellular extracts from reproductive organs and accessory sex glands of six rams, and in the seminal plasma of a further eight rams. When four of the latter rams were subjected to vasectomy, to isolate ejaculate contents to only the secretions of the accessory sex glands, the vesicles were largely eliminated from their ejaculates, while vesicles were still present in the ejaculates of the four control rams. The constituents of the cytoplasmic droplets and membrane vesicles derived from the seminal plasma were compared by transmission electron microscopy (TEM). Vesicles present in the cytoplasmic droplets were similar in morphology but smaller on average than those in the seminal plasma. It was concluded that the membrane vesicles in ram seminal plasma originate from either the cytoplasmic droplets, or a combination of vesicles from the droplets and the epididymis. [source]

Immunohistochemical and Biomolecular Identification of Orphanin FQ, eNOS, Atrial natriuretic Factor and Oxytocin in Rat Seminal Vesicles

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2009
A. Mauro
Summary In previous studies performed on rodents, we detected the presence of adreno-cholinergic and peptidergic innervation in seminal vesicles and other organs of the male genital system, such as prostate and deferent duct, in which we also investigated the expression of NOS and NADPH-diaphorase. During this project, we focused our attention on the expression of some peptides involved in local control of smooth muscle relaxation, contractility, vasodilatation and control of blood flow in rat seminal vesicles. We investigated, through immunohistochemistry and RT-PCR, the presence of four peptides: orphanin, eNOS, ANF and oxytocin. Immunohistochemistry was used to detect the presence of the proteins, whereas RT-PCR analysis confirmed gene expression of orphanin, eNOS and ANF, but not oxytocin. In our opinion, orphanin, eNOS and ANF could have paracrine effects regulating the function of seminal vesicles, whereas oxytocin, which may reach this anatomical district through the blood flow, may have a hormonal action. This is a pilot study that, with further investigation, may allow to better clarify the role of these molecules in the control of seminal vesicle tissues' homeostasis. [source]

Localization of Hyaluronic Acid in the Seminal Vesicles of the Miniature Pig

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2007
A. Sakairi
Summary We studied the detailed localization of hyaluronic acid in the seminal vesicles of the miniature pig, using hyaluronic acid-binding protein as a specific histochemical probe at the ultrastructural level. According to the results, the basolateral surface of the plasma membrane of the glandular epithelial cells, was found to contain hyaluronan. However, abundantly present was hyaluronan in the subepithelial connective tissue, in particular, in the extracellular matrix surrounding the fibroblasts, smooth muscle cells, small blood vessels and capillaries. The substance was also observed in the surface coat of the plasma membrane of the fibroblasts, but not in that of the smooth muscle cells. The findings suggest that hyaluronan in the seminal vesicles of the miniature pig is synthesized onto the surface coat of the plasma membrane of the fibroblasts, is contributed to the extracellular matrix, and consequently concentrates in the subepithelial connective tissue. The substance may particularly be involved in a variety of cellular functions to maintain morphological organization as well as to regulate physiological homeostasis in the reproductive organ of this species, rather than participate in sperm functions. [source]

RAFT Synthesis of Sterically Stabilized Methacrylic Nanolatexes and Vesicles by Aqueous Dispersion Polymerization,

ANGEWANDTE CHEMIE, Issue 24 2010
Yuting Li Dr.
Größenkontrolliert: Sterisch stabilisierte Methacrylat-Nanolatices sind durch wässrige Dispersionspolymerisation unter Anwendung von RAFT-Techniken zugänglich (siehe Schema; CTA = Kettentransferreagens). Die Größe der Partikel kann über die Länge der Poly(HPMA)-Ketten präzise eingestellt werden. [source]

Nanometer-Sized Fluorous Fullerene Vesicles in Water and on Solid Surfaces,

ANGEWANDTE CHEMIE, Issue 9 2010
Tatsuya Homma
Ein neuer Dreh für Buckyballs: Ein fluoriertes Fullerenamphiphil ohne das übliche Motiv ,polarer Kopf/nichtpolarer Schwanz" bildet über die Kohäsionskraft des Fullerens in Wasser Vesikeln (F grün, C grau). Die fluorierten Ketten nehmen die Vesikeloberfläche ein, und Vesikellösungen können Perfluoroctan lösen. Anders als Lipidvesikeln ist die fluorierte Vesikel sehr robust und behält ihre Kugelform sogar auf einem festen Substrat im Hochvakuum bei. [source]

Sweet Talking Double Hydrophilic Block Copolymer Vesicles

ANGEWANDTE CHEMIE, Issue 2 2010
George Pasparakis
No abstract is available for this article. [source]

Micelles and Vesicles Formed by Polyoxometalate,Block Copolymer Composites,

ANGEWANDTE CHEMIE, Issue 44 2009
Weifeng Bu Dr.
Kern-Schale-Komposite wurden durch Einbetten eines hydrophilen Polyoxometallats (POM) in Poly(styrol- b -4-vinyl- N -methylpyridiniumiodid)-Matrices in saurer wässriger Lösung erhalten (siehe Schema). Beim Dispergieren in Toluol entstehen selbstorganisierte Micell- und Vesikelstrukturen (siehe TEM-Bilder), deren Morphologie über den POM-Anteil gesteuert werden kann. [source]

Synthesis of Modular "Inorganic,Organic,Inorganic" Polyoxometalates and Their Assembly into Vesicles,

ANGEWANDTE CHEMIE, Issue 44 2009
Chullikkattil
Verknüpfte Cluster: Eine neue Klasse anorganisch-organisch-anorganischer Hybride mit Größen von etwa 3.4,nm wurde durch kovalente Funktionalisierung V3 -überdachter Wells-Dawson-Cluster mit linearen Bis(tris)-Liganden hergestellt (siehe Schema; TBA=nBu4N+) sowie röntgenkristallographisch und mit ESI-MS charakterisiert. Die Verbindungen weisen Tensideigenschaften auf (dynamische Lichtstreuung) und bilden in Lösung supramolekulare Vesikel. [source]

Microfluidic Formation of Monodisperse, Cell-Sized, and Unilamellar Vesicles,

ANGEWANDTE CHEMIE, Issue 35 2009
Sadao Ota
Sanft dem Strom hinab: Mit einer Mikrofluidiktechnik werden in einem kontinuierlichen Fluidstrom monodisperse unilamellare Phospholipidvesikel aus einer einzigen Doppelschicht erzeugt (siehe Bild). Da die Vesikel robust sind und effizient eine Vielzahl an Molekülen in hohen Konzentrationen einkapseln, eignen sie sich als Transportvehikel und als Modelle für Zellsysteme. [source]

Toxic epidermal necrolysis and neutropaenia: Complications of omeprazole

AUSTRALASIAN JOURNAL OF DERMATOLOGY, Issue 3 2009
Avnesh S Thakor
ABSTRACT Worldwide, proton pump inhibitors (PPI) are one of the most frequently prescribed drugs; however, up to 70% of patients taking these drugs have no appropriate indication. Although PPI are relatively well tolerated, they are not free from side-effects and several life-threatening complications are associated with them. In the present report, a 43-year-old woman presented to her general practitioner with an erythematous rash over her face and chest, having been started on omeprazole for chronic abdominal bloating. Over the next 24 h she became increasingly unwell and was admitted to hospital with shortness of breath, pyrexia and the rash spreading over her back, arms and legs. Vesicles had now started to appear within the erythematous regions over her upper body and within 24 h the rash became confluent and desquamative, spreading to involve her entire body. A diagnosis of toxic epidermal necrolysis (TEN) was made. Despite supportive treatment within a critical care setting, she became neutropaenic and her skin loss became more extensive, resulting in 95% epidermal detachment. This case highlights that TEN is a life-threatening condition associated with a high incidence of morbidity and mortality. Optimal management requires early diagnosis and transfer to a specialized unit. Clinicians need to be aware that PPI are not free from side-effects and that their routine prescription should be strongly discouraged. [source]

Affinity Purification of Lipid Vesicles

BIOTECHNOLOGY PROGRESS, Issue 1 2004
Boris Peker
We present a novel column chromatography technique for recovery and purification of lipid vesicles, which can be extended to other macromolecular assemblies. This technique is based on reversible binding of biotinylated lipids to monomeric avidin. Unlike the very strong binding of biotin and biotin-functionalized molecules to streptavidin, the interaction between biotin-functionalized molecules and monomeric avidin can be disrupted effectively by ligand competition from free biotin. In this work, biotin-functionalized lipids (biotin-PEG-PE) were incorporated into synthetic lipid vesicles (DOPC), resulting in unilamellar biotinylated lipid vesicles. The vesicles were bound to immobilized monomeric avidin, washed extensively with buffer, and eluted with a buffer supplemented with free biotin. Increasing the biotinyl lipid molar ratio beyond 0.53% of all lipids did not increase the efficiency of vesicle recovery. A simple adsorption model suggests 1.1 × 1013 active binding sites/mL of resin with an equilibrium binding constant of K = 1.0 × 108 M,1. We also show that this method is very robust and reproducible and can accommodate vesicles of varying sizes with diverse contents. This method can be scaled up to larger columns and/or high throughput analysis, such as a 96-well plate format. [source]

Giant Vesicles: Preparations and Applications

CHEMBIOCHEM, Issue 7 2010
Peter Walde Prof. Dr.
Abstract There is considerable interest in preparing cell-sized giant unilamellar vesicles from natural or nonnatural amphiphiles because a giant vesicle membrane resembles the self-closed lipid matrix of the plasma membrane of all biological cells. Currently, giant vesicles are applied to investigate certain aspects of biomembranes. Examples include lateral lipid heterogeneities, membrane budding and fission, activities of reconstituted membrane proteins, or membrane permeabilization caused by added chemical compounds. One of the challenging applications of giant vesicles include gene expressions inside the vesicles with the ultimate goal of constructing a dynamic artificial cell-like system that is endowed with all those essential features of living cells that distinguish them from the nonliving form of matter. Although this goal still seems to be far away and currently difficult to reach, it is expected that progress in this and other fields of giant vesicle research strongly depend on whether reliable methods for the reproducible preparation of giant vesicles are available. The key concepts of currently known methods for preparing giant unilamellar vesicles are summarized, and advantages and disadvantages of the main methods are compared and critically discussed. [source]

Protein Incorporation in Giant Lipid Vesicles under Physiological Conditions

CHEMBIOCHEM, Issue 2 2010
Paige M. Shaklee Dr.
Life's construction zone: Proteins were incorporated into giant vesicles (GVs) under physiological conditions by using electroformation. The figure shows these fluorescently labeled GVs in which proteins are encapsulated. Our method opens doors to investigating the membrane properties of native, intracellular membranes. [source]

ChemInform Abstract: Synthesis of Modular "Inorganic,Organic,Inorganic" Polyoxometalates and Their Assembly into Vesicles.

CHEMINFORM, Issue 51 2009
Chullikkattil P. Pradeep
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Vesicles to Concentrate Iron in Low-Iron Media: An Attempt to Mimic Marine Siderophores

CHEMISTRY - A EUROPEAN JOURNAL, Issue 12 2008
Lucie Bednarova Dr.
Abstract Amphiphilic catechol-type iron chelators were studied with the aim of mimicking the properties of marine bacterial siderophores. The FeIII complexation constants and aqueous solution speciation of LS10, a sulfonated catechol unit that has a C10 lipophilic carbon chain connected by an amide linkage, were determined by spectrophotometric titration. The calculated value of pFe3+ is 18.1 at pH,7.4. Cryogenic transmission electron microscopy showed that the tris(catecholate) ferric complex formed at physiological pH initially assembles into micelles, in which the catecholate,iron units stay on the exterior of the micelle. The average diameter of these micelles was estimated to be 4.2,nm. The micelles then slowly rearrange into clusters of different sizes, which leads to the formation of unilamellar and bilamellar vesicles. The reorganization processes are comparable to those observed by Butler et al. for the marinobactin siderophores produced by marine bacteria, but in contrast to the marinobactins, vesicles of the Fe3+,LS10 complex form without an excess of iron relative to ligand concentration. The time-dependent micelle-to-vesicle transition is discussed herein. [source]