scholarly journals Nanometer-Scale Pores: Potential Applications for Analyte Detection and DNA Characterization

2002 ◽  
Vol 18 (4) ◽  
pp. 185-191 ◽  
Author(s):  
John J. Kasianowicz
Keyword(s):  
Transmembrane Protein ◽  
Nanometer Scale ◽  
Single Channels ◽  
Lipid Bilayer Membranes ◽  
Bilayer Membranes ◽  
Dna Characterization ◽  
Wide Range ◽  
Potential Applications ◽  
Analyte Detection

Several classes of transmembrane protein ion channels function in vivo as sensitive and selective detection elements for analytes. Recent studies on single channels reconstituted into planar lipid bilayer membranes suggest that nanometer-scale pores can be used to detect, quantitate and characterize a wide range of analytes that includes small ions and single stranded DNA. We briefly review here these studies and identify leaps in technology that, if realized, might lead to innovations for the early detection of cancer.

NMR studies of enzymatic rates in vitro and in vivo by magnetization transfer

1984 ◽  
Vol 17 (1) ◽  
pp. 83-124 ◽  
Author(s):  
J. R. Alger ◽  
R. G. Shulman
Keyword(s):  
Creatine Kinase ◽  
Chemical Reactions ◽  
Magnetization Transfer ◽  
Living Systems ◽  
Nmr Studies ◽  
Wide Range ◽  
Potential Applications

Magnetization transfer techniques are specialized NMR experiments which can measure the rate of chemical reactions while concentrations of products and reactants are maintained constant. These techniques are being used to measure the rates of enzyme catalysed reactions in a variety of living systems and in vitro. The magnetization transfer measurements in vivo of the ATP synthetase and the creatine kinase reactions have been particularly useful in describing rates of major energy transducing reactions involving ATP and phosphocreatine. As a result, a wide range of biomedicai scientists are becoming aware of the potentials of these techniques. The purpose of this review is thus threefold: first, to present a concise, conceptual review of the underlying principles for these non-specialists; secondly, to review the important biochemical applications of the method which have appeared, and thirdly, to discuss potential applications and limitations of the method.

scholarly journals Novel In Vivo-Degradable Cellulose-Chitin Copolymer from Metabolically Engineered Gluconacetobacter xylinus

2010 ◽  
Vol 76 (18) ◽  
pp. 6257-6265 ◽  
Author(s):  
Vikas Yadav ◽  
Bruce J. Paniliatis ◽  
Hai Shi ◽  
Kyongbum Lee ◽  
Peggy Cebe ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
De Novo ◽  
Biomass Conversion ◽  
Gluconacetobacter Xylinus ◽  
The Poor ◽  
Wide Range ◽  
Potential Applications ◽  
Rapid Hydrolysis

ABSTRACT Despite excellent biocompatibility and mechanical properties, the poor in vitro and in vivo degradability of cellulose has limited its biomedical and biomass conversion applications. To address this issue, we report a metabolic engineering-based approach to the rational redesign of cellular metabolites to introduce N-acetylglucosamine (GlcNAc) residues into cellulosic biopolymers during de novo synthesis from Gluconacetobacter xylinus. The cellulose produced from these engineered cells (modified bacterial cellulose [MBC]) was evaluated and compared with cellulose produced from normal cells (bacterial cellulose [BC]). High GlcNAc content and lower crystallinity in MBC compared to BC make this a multifunctional bioengineered polymer susceptible to lysozyme, an enzyme widespread in the human body, and to rapid hydrolysis by cellulase, an enzyme commonly used in biomass conversion. Degradability in vivo was demonstrated in subcutaneous implants in mice, where modified cellulose was completely degraded within 20 days. We provide a new route toward the production of a family of tailorable modified cellulosic biopolymers that overcome the longstanding limitation associated with the poor degradability of cellulose for a wide range of potential applications.

scholarly journals SAT-315 CircVPS13c Promotes Tumor Growth and Invasiveness in Pituitary Adenoma by Downregulating IFITM1

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Xiaobing Jiang ◽  
weiyu zhang ◽  
piaopiao zhang
Keyword(s):  
Pituitary Adenoma ◽  
Tumor Growth ◽  
Transmembrane Protein ◽  
Circular Rnas ◽  
Tumor Invasiveness ◽  
In Vivo Experiments ◽  
Wide Range ◽  
Associated Proteins

Abstract Background and objectives Invasive nonfunctioning pituitary adenoma (NFPA) remains the major cause of hypopituitarism and infertility. Increasing evidences suggest that circular RNAs (circRNAs) exert crucial functions in regulating gene expression in a wide range of tumors. The present study was designed to explore the role of circRNAs in proliferation and invasion of NFPAs. Methods The expression profile of circRNAs was compared with circRNA array between NFPA (n=10) and normal pituitary tissues (n=4), invasive (n=5) and noninvasive (n=5) NFPA samples. A total of 249 circRNAs were shown to be significantly upregulated in human invasive NFPA tissues, comparing to the noninvasive ones. CircVPS13C was identified for further study, whose oncogenic effect were explored with in vitro and in vivo experiments. Results CircVPS13C was markedly upregulated in NFPA samples and positively correlated with NFPA invasiveness. Silencing of circVPS13C effectively suppressed NFPA cell proliferation, invasiveness and promoted apoptosis, in vitro, and suppressed tumor growth, in vivo. The oncogenic effects were significantly enhanced when circVPS13C was overexpressed. By whole exome sequencing, interferon induced transmembrane protein 1 (IFITM1) was found significantly increased in cells with circVPS13C knockout. Decreased level of IFITM1 protein was confirmed in NFPAs samples, and negatively correlated with the level of circVPS13C and tumor invasiveness. Upregulation of IFITM1 could partly reverse the effect of IFITM1 on tumor cells, and IFITM1 downregulating enhanced the oncogenic effect of circVPS13C. CHIRP analysis suggested that circVPS13C may inhibit the IFITM1 transcription by competitively binding the RNA-associated proteins. Conclusions CircVPS13C promotes NFPA growth and invasiveness by regulating tumor suppressor IFITM1, revealing a therapeutic target in preventing the tumorigenesis of NFPA.

scholarly journals Periphery Decorated and Core Initiated Neutral and Polyanionic Borane Large Molecules: Forthcoming and Promising Properties for Medicinal Applications

2019 ◽  
Vol 26 (26) ◽  
pp. 5036-5076 ◽  
Author(s):  
Clara Viñas ◽  
Rosario Núñez ◽  
Ines Bennour ◽  
Francesc Teixidor
Keyword(s):  
Self Assembly ◽  
Steric Structure ◽  
Lipid Bilayer Membranes ◽  
Aryl Ether ◽  
Bilayer Membranes ◽  
Boron Clusters ◽  
Large Molecules ◽  
Design And Synthesis ◽  
Novel Applications

A mini-review based on radial growing macromolecules and core initiated Borane periphery decorated with o-carboranes and metallacarboranes that has been developed in the authors laboratories is reported. The review is divided into four sections; three of them are related to the design and synthesis of these large boron-containing molecules and the fourth deals with the unique properties of anionic metallacarborane molecules that provide a glimpse of their potential for their promising use in medicinal applications. Their unique stability along with their geometrical and electronic properties, as well as the precise steric structure of 1,2-closo-C2B10H12 (o-carborane) that has the potential for the incorporation of many substituents: at the carbon (Cc), at the boron and at both carbon and boron vertices, suggests this cluster as an innovative building block or platform for novel applications that cannot be achieved with organic hydrocarbon compounds. Poly(aryl-ether) dendrimers grown from fluorescent cores, such as 1,3,5-triarylbenzene or meso-porphyrins, have been decorated with boron clusters to attain rich boron containing dendrimers. Octasilsesquioxane cubes have been used as a core for its radial growth to get boron-rich large molecules. The unique properties of cobaltabisdicarbollide cluster, which include: i) self-assembly in water to produce monolayer nano-vesicles, ii) crossing lipid bilayer membranes, iii) interacting with membrane cells, iv) facilitating its visualization within cells by Raman and fluorescence techniques and v) their use as molecular platform for “in vivo” imaging are discussed in detail.

scholarly journals Effect of Peptide PV on the Ionic Permeability of Lipid Bilayer Membranes

1974 ◽  
Vol 63 (4) ◽  
pp. 492-508 ◽  
Author(s):  
H. P. Ting-Beall ◽  
M. T. Tosteson ◽  
B. F. Gisin ◽  
D. C. Tosteson
Keyword(s):  
Lipid Bilayers ◽  
Membrane Conductance ◽  
Equilibrium Potential ◽  
Lipid Bilayer Membranes ◽  
Bilayer Membranes ◽  
Membrane Surfaces ◽  
Zero Current ◽  
Wide Range ◽  
Current Flows ◽  
Calculated Equilibrium

This paper reports the effects of peptide PV (primary structure: cyclo-(D-val-L-pro-L-val-D-pro)δ) on the electrical properties of sheep red cell lipid bilayers. The membrane conductance (Gm) induced by PV in either Na+ or K+ medium is proportional to the concentration of PV in the aqueous phase. The PV concentration required to produce a comparable increase in Gm in K+ medium is about 104 times greater than for its analogue, valinomycin (val). Although the selectivity sequence for PV and val is similar, K+ ≳ Rb+ > Cs+ > NH4+ > TI+ > Na+ > Li+; the ratio of GGm in K+ to that in Na+ is about 10 for PV compared to > 103 for val. When equal concentrations of PV are added to both sides of a bilayer, the membrane current approaches a maximum value independent of voltage when the membrane potential exceeds 100 mV. When PV is added to only one side of a bilayer separating identical salt solutions of either Na+ or K+ salts, rectification occurs such that the positive current flows more easily away rather than toward the side containing the carrier. Under these conditions, a large, stable, zero-current potential (VVm) is also observed, with the side containing PV being negative. The magnitude of this VVm is about 90 mV and relatively independent of PV concentration when the latter is larger than 2 Times; 10–5 M. From a model which assumes that Vm equals the equilibrium potential for the PV-cation complexes (MS+) and that the reaction between PV and cations is at equilibrium on the two membrane surfaces, we compute the permeability of the membrane to free PV to be about 10–5 cm s–1, which is about 10–7 times the permeability of similar membranes to free val. This interpretation is supported by the fact that the observed values of Vm are in agreement with the calculated equilibrium potential for MS+ over a wide range of ratios of concentrations of total PV in the two bathing solutions, if the unstirred layers are taken into account in computing the MS+ concentrations at the membrane surfaces.

Investigation of transmembrane protein fused in lipid bilayer membranes supported on porous silicon

2012 ◽  
Vol 37 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Khalid Hasan Tantawi ◽  
Ramon Cerro ◽  
Bakhrom Berdiev ◽  
M. Elena Diaz Martin ◽  
Francisco Javier Montes ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Lipid Bilayer ◽  
Transmembrane Protein ◽  
Lipid Bilayer Membranes ◽  
Bilayer Membranes

A Close-To-Native System to Study Membrane Protein Dynamics by Single-Molecule Optical Microscopy: an Application to Bacteriorhodopsin

2001 ◽  
Vol 7 (S2) ◽  
pp. 30-31
Author(s):  
Nicoletta Kahya ◽  
Eve I. Pécheur ◽  
Douwe A. Wiersma ◽  
Dick Hoekstra
Keyword(s):  
Optical Microscopy ◽  
Lipid Bilayers ◽  
Single Molecule ◽  
Transmembrane Protein ◽  
Passive Component ◽  
Signal Transducers ◽  
Wide Range ◽  
Minimum Number

Biological membranes are not just a passive component of the cells, they actively support their functioning as the imbedded protein machineries carry out a wide range of crucial biochemical processes. Although studies in vivo are becoming more and more accessible to single-molecule optical microscopy, in vitro studies are still very much informative for the understanding of individual biological machineries. One of the major goals is to define the minimum number of components of a machinery that is necessary for a particular step, thereby allowing detailed studies of the mechanism of action. Reconstitution of a transmembrane protein system in artificial membranes (liposomes) is the main method for such a strategy, which thus may provide the option to investigate the functioning of transport proteins, ion channels, fusion machineries, and signal transducers in relation to their environment.We present a novel procedure in order to reconstitute transmembrane proteins in chemically well-defined and close-to-native lipid bilayers, providing an in vitro system for single-molecule optical microscopy. Furthermore, an application of this technique is shown in the case of a single-molecule study of protein-protein and protein-lipid interactions for the light-induced proton pump bacteriorhodopsin.In this study, Giant Unilamellar Vesicles (GUV), 10-100 μm sized, are used as lipid bilayer models for several reasons.

scholarly journals Biocompatibility and Effectiveness Evaluation of a New Hemostatic Embolization Agent: Thrombin Loaded Alginate Calcium Microsphere

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Fengqi Xuan ◽  
Jingjing Rong ◽  
Ming Liang ◽  
Xuwen Zhang ◽  
Jingyang Sun ◽  
...  
Keyword(s):  
Histological Study ◽  
Interventional Treatment ◽  
Artery Embolization ◽  
Wide Range ◽  
Superselective Embolization ◽  
Potential Applications ◽  
Hepatic Artery Injury ◽  
Good Biocompatibility ◽  
Dog Liver

Background. Until now, there has been no ideal embolization agent for hemorrhage in interventional treatment. In this study, the thrombin was encapsulated in alginate calcium microsphere using electrostatic droplet technique to produce new embolization agent: thrombin loaded alginate calcium microspheres (TACMs).Objectives. The present work was to evaluate the biocompatibility and hemostatic efficiency of TACMs.Methods.Cell cytotoxicity, hemolysis, and superselective embolization of dog liver arteries were performed to investigate the biocompatibility of TACMs. To clarify the embolic effect of TACMs mixed thrombus in vivo, hepatic artery injury animal model of 6 beagles was established and transcatheter artery embolization for bleeding was performed.Results. Coculture with VECs revealed the noncytotoxicity of TACMs, and the hemolysis experiment was negligible. Moreover, the histological study of TACMs in liver blood vessel showed signs of a slight inflammatory reaction. The results of transcatheter application of TACMs mixed thrombus for bleeding showed that the blood flow was shut down completely after the TACMs mixed thrombus was delivered and the postprocedural survival rate of animal models at 12 weeks was 100%.Conclusions. With their good biocompatibility and superior hemostatic efficiency, TACMs might be a promising new hemostatic agent with a wide range of potential applications.

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