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Surface Regions (surface + regions)
Selected AbstractsAffinity-Based Protein Surface Pattern Formation by Ligand Self-Selection from Mixed Protein SolutionsADVANCED FUNCTIONAL MATERIALS, Issue 19 2009Manish Dubey Abstract Photolithographically prepared surface patterns of two affinity ligands (biotin and chloroalkane) specific for two proteins (streptavidin and HaloTag, respectively) are used to spontaneously form high-fidelity surface patterns of the two proteins from their mixed solution. High affinity protein-surface self-selection onto patterned ligands on surfaces exhibiting low non-specific adsorption rapidly yields the patterned protein surfaces. Fluorescence images after protein immobilization show high specificity of the target proteins to their respective surface patterned ligands. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging further supports the chemical specificity of streptavidin and HaloTag for their surface patterned ligands from mixed protein solutions. However, ToF-SIMS did detect some non-specific adsorption of bovine serum albumin, a masking protein present in excess in the adsorbing solutions, on the patterned surfaces. Protein amino acid composition, surface coverage, density, and orientation are important parameters that determine the relative ToF-SIMS fragmentation pattern yields. ToF-SIMS amino acid-derived ion fragment yields summed to produce surface images can reliably determine which patterned surface regions contain bound proteins, but do not readily discriminate between different co-planar protein regions. Principal component analysis (PCA) of these ToF-SIMS data, however, improves discrimination of ions specific to each protein, facilitating surface protein pattern identification and image contrast. [source] Three-dimensional MRI mapping of minimum temperatures achieved in microwave and conventional food processingINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2001John R. Bows Microbiological assurance protocols for food preservation are based on the ,worst-case' slowest heating point within the food product. For conduction-limited processing, this leads to well-known overheating near surface regions of products, with resultant quality loss. For volumetric heating processes such as microwave heating, it is practically impossible to guarantee where the slowest heating point will be. Consequently, microwave heating regimes are generally excessive and product quality is often similar to conventional conduction-limited heating processes. It is well known that Magnetic Resonance Imaging (MRI) can provide three-dimensional (3D) images which quantify the spatial distribution of water in foods, and also that the MRI parameters of water are temperature dependent. The present study demonstrates that a combination of these two concepts has led to a new approach for the validation of thermal processing in food manufacture. The potential for on-line assurance of minimum and maximum temperatures for manufacture of microbiologically assured, minimally processed, high quality food is discussed. [source] Collagen structure: The molecular source of the tendon magic angle effectJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2007Gary D. Fullerton PhD Abstract This review of tendon/collagen structure shows that the orientational variation in MRI signals from tendon, which is referred to as the "magic angle" (MA) effect, is caused by irreducible separation of charges on the main chain of the collagen molecule. These charges are held apart in a vacuum by stereotactic restriction of protein folding due in large part to a high concentration of hydroxyproline ring residues in the amino acids of mammalian collagen. The elevated protein electrostatic energy is reduced in water by the large dielectric constant of the highly polar solvent (, , 80). The water molecules serve as dielectric molecules that are bound by an energy that is nearly equivalent to the electrostatic energy between the neighboring positive and negative charge pairs in a vacuum. These highly immobilized water molecules and secondary molecules in the hydrogen-bonded water network are confined to the transverse plane of the tendon. Orientational restriction causes residual dipole coupling, which is directly responsible for the frequency and phase shifts observed in orientational MRI (OMRI) described by the MA effect. Reference to a wide range of biophysical measurements shows that native hydration is a monolayer on collagen hm = 1.6 g/g, which divides into two components consisting of primary hydration on polar surfaces hpp = 0.8 g/g and secondary hydration hs = 0.8 g/g bridging over hydrophobic surface regions. Primary hydration further divides into side-chain hydration hpsc = 0.54 g/g and main-chain hydration hpmc = 0.263 g/g. The main-chain fraction consists of water that bridges between charges on the main chain and is responsible for almost all of the enthalpy of melting ,H = 70 J/g-dry mass. Main-chain water bridges consist of one extremely immobilized Ramachandran water bridge per tripeptide hRa = 0.0658 g/g and one double water bridge per tripeptide hdwb = 0.1974 g/g, with three water molecules that are sufficiently slowed to act as the spin-lattice relaxation sink for the entire tendon. J. Magn. Reson. Imaging 2007. © 2007 Wiley-Liss, Inc. [source] Differential activity patterns in the masseter muscle under simulated clenching and grinding forcesJOURNAL OF ORAL REHABILITATION, Issue 8 2005H. J. SCHINDLER summary, The aim of this study was to investigate (i) whether the masseter muscle shows differential activation under experimental conditions which simulate force generation during clenching and grinding activities; and (ii) whether there are (a) preferentially active muscle regions or (b) force directions which show enhanced muscle activation. To answer these questions, the electromyographic (EMG) activity of the right masseter muscle was recorded with five intramuscular electrodes placed in two deep muscle areas and in three surface regions. Intraoral force transfer and force measurement were achieved by a central bearing pin device equipped with three strain gauges (SG). The activity distribution in the muscle was recorded in four different mandibular positions (central, left, right, anterior). In each position, maximum voluntary contraction (MVC) was exerted in vertical, posterior, anterior, medial and lateral directions. The investigated muscle regions showed different amount of EMG activity. The relative intensity of the activation, with respect to other regions, changed depending on the task. In other words, the muscle regions demonstrated heterogeneous changes of the EMG pattern for the various motor tasks. The resultant force vectors demonstrated similar amounts in all horizontal bite directions. Protrusive force directions revealed the highest relative activation of the masseter muscle. The posterior deep muscle region seemed to be the most active compartment during the different motor tasks. The results indicate a heterogeneous activation of the masseter muscle under test conditions simulating force generation during clenching and grinding. Protrusively directed bite forces were accompanied by the highest activation in the muscle, with the posterior deep region as the most active area. [source] Kin1 is a plasma membrane-associated kinase that regulates the cell surface in fission yeastMOLECULAR MICROBIOLOGY, Issue 5 2010Angela Cadou Summary Cell morphogenesis is a complex process that depends on cytoskeleton and membrane organization, intracellular signalling and vesicular trafficking. The rod shape of the fission yeast Schizosaccharomyces pombe and the availability of powerful genetic tools make this species an excellent model to study cell morphology. Here we have investigated the function of the conserved Kin1 kinase. Kin1-GFP associates dynamically with the plasma membrane at sites of active cell surface remodelling and is present in the membrane fraction. Kin1, null cells show severe defects in cell wall structure and are unable to maintain a rod shape. To explore Kin1 primary function, we constructed an ATP analogue-sensitive allele kin1-as1. Kin1 inhibition primarily promotes delocalization of plasma membrane-associated markers of actively growing cell surface regions. Kin1 itself is depolarized and its mobility is strongly reduced. Subsequently, amorphous cell wall material accumulates at the cell surface, a phenotype that is dependent on vesicular trafficking, and the cell wall integrity mitogen-activated protein kinase pathway is activated. Deletion of cell wall integrity mitogen-activated protein kinase components reduces kin1, hypersensitivity to stresses such as those induced by Calcofluor white and SDS. We propose that Kin1 is required for a tight link between the plasma membrane and the cell wall. [source] Correctness of a particular solution of inverse problem in rocking curve imagingPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2009Isabella Huber Abstract Local lattice misorientations on crystalline substrates can be visualized by rocking curve imaging. Local deviations from Bragg peak positions are extracted from a series of digital topographs recorded by a CCD detector under different azimuths. Bragg peaks from surface regions such as crystallites with a larger local misorientation overlap on the detector, which requires a back-projection method in order to reconstruct the misorientation components on the sample surface from the measured angular position on the detector planes. From mathematical point of view, the reconstruction problem is an inverse problem. In this paper, we formulate the forward and back-projection problems and we prove the correctness of a particular solution. The usability of the method is demonstrated on a phantom data set. [source] Epitope mapping of a monoclonal antibody against human thrombin by H/D-exchange mass spectrometry reveals selection of a diverse sequence in a highly conserved proteinPROTEIN SCIENCE, Issue 6 2002Abel Baerga-Ortiz Abstract The epitope of a monoclonal antibody raised against human thrombin has been determined by hydrogen/deuterium exchange coupled to MALDI mass spectrometry. The antibody epitope was identified as the surface of thrombin that retained deuterium in the presence of the monoclonal antibody compared to control experiments in its absence. Covalent attachment of the antibody to protein G beads and efficient elution of the antigen after deuterium exchange afforded the analysis of all possible epitopes in a single MALDI mass spectrum. The epitope, which was discontinuous, consisting of two peptides close to anion-binding exosite I, was readily identified. The epitope overlapped with, but was not identical to, the thrombomodulin binding site, consistent with inhibition studies. The antibody bound specifically to human thrombin and not to murine or bovine thrombin, although these proteins share 86% identity with the human protein. Interestingly, the epitope turned out to be the more structured of two surface regions in which higher sequence variation between the three species is seen. [source] Histochemical properties of skeletal muscles in Japanese cattle and their meat production abilityANIMAL SCIENCE JOURNAL, Issue 5 2003Takafumi GOTOH ABSTRACT The compositional characteristics of the three basic types of myofiber, namely type I (slow-twitch oxidative), type IIA (fast-twitch oxidative glycolytic) and type IIB (fast-twitch glycolytic), are clarified in the skeletal muscles of Japanese Black cattle. The myofiber composition, which is characteristic of the muscles of Japanese Black cattle, markedly changes during their growth, when some type IIA myofibers are transformed into type I or IIB, depending on the different muscles. Independent of these changes with growth, inter- and intramuscular variations of myofiber type distribution is evident. The small extensor muscles in deep regions around bone contain a lot of type I myofibers, whereas the large muscles at surface regions have many type II myofibers. Japanese Black cattle have typical white muscles such as the Longissimus thoracis and Semitendinosus, containing half the myofibers as red (type I + IIA). The muscles of Japanese Black cattle show a tendency to contain a higher percentage of type I myofibers than other breeds over an intrabreed variation of the myofiber type composition. In the big muscles such as the Longissimus thoracis and Biceps femoris, a great diversity of myofiber type composition is observed among the different regions. When fattened, heifers produce Longissimus thoracis and Biceps femoris muscles of smaller weight than steers, but in heifers the myofiber size in each type is rather larger. In the Psoas major, Vastus lateralis and Serratus ventralis muscles, heifers contain a higher frequency of red (type I + IIA) myofibers with no differences in myofiber size. Among the several muscles of fattened Japanese Black steers, the percentage distribution of type I myofibers has a positive correlation with the percentage amount of intramuscular fat. From these results, the high potential of Japanese Black cattle to produce marbled beef could be based on the histochemical properties of myofibers in their skeletal muscles. [source] | ||||||||||||||||