Search results for " Matrix"
showing 10 items of 2053 documents
Integrin-dependent and -independent functions of astrocytic fibronectin in retinal angiogenesis
2011
Fibronectin (FN) is a major component of the extracellular matrix and functions in cell adhesion, cell spreading and cell migration. In the retina, FN is transiently expressed and assembled on astrocytes (ACs), which guide sprouting tip cells and deposit a provisional matrix for sprouting angiogenesis. The precise function of FN in retinal angiogenesis is largely unknown. Using genetic tools, we show that astrocytes are the major source of cellular FN during angiogenesis in the mouse retina. Deletion of astrocytic FN reduces radial endothelial migration during vascular plexus formation in a gene dose-dependent manner. This effect correlates with reduced VEGF receptor 2 and PI3K/AKT signalli…
QSPR/QSAR Studies of 2-Furylethylenes Using Bond-Level Quadratic Indices and Comparison with Other Computational Approaches
2017
The recently introduced, non-stochastic and stochastic quadratic indices (Marrero-Ponce <em>et al. J. Comp. Aided Mol. Des.</em> 2006, 20, 685-701) were applied to QSAR/QSPR studies of heteroatomic molecules. These novel bond-based molecular descriptors (MDs) were used for the prediction of the partition coefficient (log P), and the antibacterial activity of 34 derivatives of 2-furylethylenes. Two statistically significant QSPR models using non-stochastic and stochastic bond-based quadratic indices were obtained (R<sup>2</sup> = 0.971, s = 0.137 and R<sup>2</sup> = 0.986, s = 0.096). These models showed good stability to data variation in leave-one-out (L…
Paenibacillus larvae Chitin-Degrading Protein PlCBP49 Is a Key Virulence Factor in American Foulbrood of Honey Bees
2014
Paenibacillus larvae, the etiological agent of the globally occurring epizootic American Foulbrood (AFB) of honey bees, causes intestinal infections in honey bee larvae which develop into systemic infections inevitably leading to larval death. Massive brood mortality might eventually lead to collapse of the entire colony. Molecular mechanisms of host-microbe interactions in this system and of differences in virulence between P. larvae genotypes are poorly understood. Recently, it was demonstrated that the degradation of the peritrophic matrix lining the midgut epithelium is a key step in pathogenesis of P. larvae infections. Here, we present the isolation and identification of PlCBP49, a mo…
Sec61alpha and TRAM are Sequentially Adjacent to a Nascent Viral Membrane Protein during its ER Integration
2007
Co-translational integration of a nascent viral membrane protein into the endoplasmic reticulum membrane takes place via the translocon. We have been studying the early stages of the integration of a double-spanning plant viral movement protein to gain insights into how viral membrane proteins are transferred from the hydrophilic interior of the translocon into the hydrophobic environment of the bilayer, where the transmembrane (TM) segments of the viral proteins can diffuse freely. Photocrosslinking experiments reveal that this integration involves the sequential passage of the TM segments past Sec61alpha and translocating chain-associating membrane protein (TRAM). Each TM segment is first…
Vitamin A deficiency alters the structure and collagen IV composition of rat renal basement membranes.
2005
Retinoids can modulate the expression of extracellular matrix (ECM) proteins with variable results depending on other contributing factors. Because changes in these proteins may alter the composition and impair the function of specialized ECM structures such as basement membranes (BMs), we studied the effects of vitamin A deficiency on renal BMs during the growing period. Newborn male rats were fed a vitamin A-deficient (VAD) diet for 50 d. The ultrastructure of renal BMs was analyzed by electron microscopy. Total collagen IV, the different alpha(IV) chains, matrix degrading metalloproteinases (MMP), and tissue inhibitors of metalloproteinases (TIMP) were quantified by immunocytochemistry a…
Vitamin A Deficiency and Alterations in the Extracellular Matrix
2014
Vitamin A or retinol which is the natural precursor of several biologically active metabolites can be considered the most multifunctional vitamin in mammals. Its deficiency is currently, along with protein malnutrition, the most serious and common nutritional disorder worldwide. It is necessary for normal embryonic development and postnatal tissue homeostasis, and exerts important effects on cell proliferation, differentiation and apoptosis. These actions are produced mainly by regulating the expression of a variety of proteins through transcriptional and non-transcriptional mechanisms. Extracellular matrix proteins are among those whose synthesis is known to be modulated by vitamin A. Reti…
Effects of fabrication on the mechanics, microstructure and micromechanical environment of small intestinal submucosa scaffolds for vascular tissue e…
2013
In small intestinal submucosa scaffolds for functional tissue engineering, the impact of scaffold fabrication parameters on success rate may be related to the mechanotransductory properties of the final microstructural organization of collagen fibers. We hypothesized that two fabrication parameters, 1) preservation (P) or removal (R) of a dense collagen layer present in SIS and 2) SIS in a final dehydrated (D) or hydrated (H) state, have an effect on scaffold void area, microstructural anisotropy (fiber alignment) and mechanical anisotropy (global mechanical compliance). We further integrated our experimental measurements in a constitutive model to explore final effects on the micromechanic…
OpenMolcas: From Source Code to Insight
2019
In this article we describe the OpenMolcas environment and invite the computational chemistry community to collaborate. The open-source project already includes a large number of new developments realized during the transition from the commercial MOLCAS product to the open-source platform. The paper initially describes the technical details of the new software development platform. This is followed by brief presentations of many new methods, implementations, and features of the OpenMolcas program suite. These developments include novel wave function methods such as stochastic complete active space self-consistent field, density matrix renormalization group (DMRG) methods, and hybrid multico…
Quantum wire with periodic serial structure
1991
Electron wave motion in a quantum wire with periodic structure is treated by direct solution of the Schr\"odinger equation as a mode-matching problem. Our method is particularly useful for a wire consisting of several distinct units, where the total transfer matrix for wave propagation is just the product of those for its basic units. It is generally applicable to any linearly connected serial device, and it can be implemented on a small computer. The one-dimensional mesoscopic crystal recently considered by Ulloa, Casta\~no, and Kirczenow [Phys. Rev. B 41, 12 350 (1990)] is discussed with our method, and is shown to be a strictly one-dimensional problem. Electron motion in the multiple-stu…
Image transmission through dynamic scattering media by single-pixel photodetection
2014
Smart control of light propagation through highly scattering media is a much desired goal with major technological implications. Since interaction of light with highly scattering media results in partial or complete depletion of ballistic photons, it is in principle impossible to transmit images through distances longer than the extinction length. Nevertheless, different methods for image transmission, focusing, and imaging through scattering media by means of wavefront control have been published over the past few years. In this paper we show that single-pixel optical systems, based on compressive detection, can also overcome the fundamental limitation imposed by multiple scattering to suc…