Murine and human myogenic cells identified by elevated aldehyde dehydrogenase activity: Implications for muscle regeneration and repair

Background: Despite the initial promise of myoblast transfer therapy to restore dystrophin in Duchenne muscular dystrophy patients, clinical efficacy has been limited, primarily by poor cell survival post-transplantation. Murine muscle derived stem cells (MDSCs) isolated from slowly adhering cells (SACs) via the preplate technique, induce greater muscle regeneration than murine myoblasts, primarily due to improved post-transplantation survival, which is conferred by their increased stress resistance capacity. Aldehyde dehydrogenase (ALDH) represents a family of enzymes with important morphogenic as well as oxidative damage mitigating roles and has been found to be a marker of stem cells in both normal and malignant tissue. In this study, we hypothesized that elevated ALDH levels could identify murine and human muscle derived cell (hMDC) progenitors, endowed with enhanced stress resistance and muscle regeneration capacity. Methodology/Principal Findings: Skeletal muscle progenitors were isolated from murine and human skeletal muscle by a modified preplate technique and unfractionated enzymatic digestion, respectively. ALDHhisubpopulations isolated by fluorescence activate cell sorting demonstrated increased proliferation and myogenic differentiation capacities compared to their ALDHlocounterparts when cultivated in oxidative and inflammatory stress media conditions. This behavior correlated with increased intracellular levels of reduced glutathione and superoxide dismutase. ALDHhimurine myoblasts were observed to exhibit an increased muscle regenerative potential compared to ALDHlomyoblasts, undergo multipotent differentiation (osteogenic and chondrogenic), and were found predominately in the SAC fraction, characteristics that are also observed in murine MDSCs. Likewise, human ALDHhihMDCs demonstrated superior muscle regenerative capacity compared to ALDHlohMDCs. Conclusions: The methodology of isolating myogenic cells on the basis of elevated ALDH activity yielded cells with increased stress resistance, a behavior that conferred increased regenerative capacity of dystrophic murine skeletal muscle. This result demonstrates the critical role of stress resistance in myogenic cell therapy as well as confirms the role of ALDH as a marker for rapid isolation of murine and human myogenic progenitors for cell therapy. © 2011 Vella et al

Accounting conservatism and bankruptcy risk

Date posted: June 6, 2010 ; Last revised: July 14, 2015This study examines the relation between accounting conservatism and bankruptcy risk using a large sample of U.S listed firms from fiscal year 1989 to 2007. We present evidence that unconditional and conditional conservatism generally mitigate subsequent bankruptcy risk by creating cushions for bad times and reducing information asymmetry about bad news. We identify two channels for accounting conservatism to mitigate bankruptcy risk: enhancing cash holdings and constraining earnings management. The effect of accounting conservatism does not change for firms with extreme distress and income smoothing, but weakens for firms with debt contracts referenced by credit default swaps (CDS), consistent with CDS lowering debtholder monitoring. Results are robust to reverse causality, relations between unconditional and conditional conservatism, and alternative measures of bankruptcy risk and accounting conservatism. These findings extend research on accounting conservatism, bankruptcy risk and debt contracting, and help inform debates regarding conservatism's role as a pervasive property and long-standing tenet of financial accounting.postprin

3′-UTR engineering to improve soluble expression and fine-tuning of activity of cascade enzymes in Escherichia coli

3'-Untranslated region (3'UTR) engineering was investigated to improve solubility of heterologous proteins (e.g., Baeyer-Villiger monooxygenases (BVMOs)) in Escherichia coli. Insertion of gene fragments containing putative RNase E recognition sites into the 3'UTR of the BVMO genes led to the reduction of mRNA levels in E. coli. Importantly, the amounts of soluble BVMOs were remarkably enhanced resulting in a proportional increase of in vivo catalytic activities. Notably, this increase in biocatalytic activity correlated to the number of putative RNase E endonucleolytic cleavage sites in the 3'UTR. For instance, the biotransformation activity of the BVMO BmoF1 (from Pseudomonas fluorescens DSM50106) in E. coli was linear to the number of RNase E cleavage sites in the 3'UTR. In summary, 3'UTR engineering can be used to improve the soluble expression of heterologous enzymes, thereby fine-tuning the enzyme activity in microbial cells.1184Ysciescopu

Localized-Surface-Plasmon Enhanced the 357 nm Forward Emission from ZnMgO Films Capped by Pt Nanoparticles

The Pt nanoparticles (NPs), which posses the wider tunable localized-surface-plasmon (LSP) energy varying from deep ultraviolet to visible region depending on their morphology, were prepared by annealing Pt thin films with different initial mass-thicknesses. A sixfold enhancement of the 357 nm forward emission of ZnMgO was observed after capping with Pt NPs, which is due to the resonance coupling between the LSP of Pt NPs and the band-gap emission of ZnMgO. The other factors affecting the ultraviolet emission of ZnMgO, such as emission from Pt itself and light multi-scattering at the interface, were also discussed. These results indicate that Pt NPs can be used to enhance the ultraviolet emission through the LSP coupling for various wide band-gap semiconductors

Design Rules for Self-Assembly of 2D Nanocrystal/Metal-Organic Framework Superstructures.

We demonstrate the guiding principles behind simple two dimensional self-assembly of MOF nanoparticles (NPs) and oleic acid capped iron oxide (Fe3 O4 ) NCs into a uniform two-dimensional bi-layered superstructure. This self-assembly process can be controlled by the energy of ligand-ligand interactions between surface ligands on Fe3 O4 NCs and Zr6 O4 (OH)4 (fumarate)6 MOF NPs. Scanning transmission electron microscopy (TEM)/energy-dispersive X-ray spectroscopy and TEM tomography confirm the hierarchical co-assembly of Fe3 O4 NCs with MOF NPs as ligand energies are manipulated to promote facile diffusion of the smaller NCs. First-principles calculations and event-driven molecular dynamics simulations indicate that the observed patterns are dictated by combination of ligand-surface and ligand-ligand interactions. This study opens a new avenue for design and self-assembly of MOFs and NCs into high surface area assemblies, mimicking the structure of supported catalyst architectures, and provides a thorough fundamental understanding of the self-assembly process, which could be a guide for designing functional materials with desired structure

Comparative Analysis of CDMA Based Wireless Communication under Radio Propagation Environment

Knowledge of the propagation characteristics of a mobile radio channel is essential to the understanding and design of a cellular system [1]. An appropriate propagation model is required when estimating the link budget or designing a Code Division Multiple Access (CDMA) system [2]. This paper deals with comparative parametric analysis for propagation path loss considering macro cell region using different models and contains comparative study with real measurement obtained from Pacific Bangladesh Telecom Limited (PBTL), a CDMA based wireless network for city Dhaka, Bangladesh

Nearly Monodispersion CoSm Alloy Nanoparticles Formed by an In-situ Rapid Cooling and Passivating Microfluidic Process

An in siturapid cooling and passivating microfluidic processhas been developed for the synthesis of nearly monodispersed cobalt samarium nanoparticles (NPs) with tunable crystal structures and surface properties. This process involves promoting the nucleation and growth of NPs at an elevated temperature and rapidly quenching the NP colloids in a solution containing a passivating reagent at a reduced temperature. We have shown that Cobalt samarium NPs having amorphous crystal structures and a thin passivating layer can be synthesized with uniform nonspherical shapes and size of about 4.8 nm. The amorphous CoSm NPs in our study have blocking temperature near 40 K and average coercivity of 225 Oe at 10 K. The NPs also exhibit high anisotropic magnetic properties with a wasp-waist hysteresis loop and a bias shift of coercivity due to the shape anisotropy and the exchange coupling between the core and the thin oxidized surface layer

Feigenbaum graphs: a complex network perspective of chaos

The recently formulated theory of horizontal visibility graphs transforms time series into graphs and allows the possibility of studying dynamical systems through the characterization of their associated networks. This method leads to a natural graph-theoretical description of nonlinear systems with qualities in the spirit of symbolic dynamics. We support our claim via the case study of the period-doubling and band-splitting attractor cascades that characterize unimodal maps. We provide a universal analytical description of this classic scenario in terms of the horizontal visibility graphs associated with the dynamics within the attractors, that we call Feigenbaum graphs, independent of map nonlinearity or other particulars. We derive exact results for their degree distribution and related quantities, recast them in the context of the renormalization group and find that its fixed points coincide with those of network entropy optimization. Furthermore, we show that the network entropy mimics the Lyapunov exponent of the map independently of its sign, hinting at a Pesin-like relation equally valid out of chaos.Comment: Published in PLoS ONE (Sep 2011

The structure of a resuscitation-promoting factor domain from Mycobacterium tuberculosis shows homology to lysozymes

Resuscitation-promoting factor (RPF) proteins reactivate stationary-phase cultures of (G+C)-rich Gram-positive bacteria including the causative agent of tuberculosis, Mycobacterium tuberculosis. We report the solution structure of the RPF domain from M. tuberculosis Rv1009 (RpfB) solved by heteronuclear multidimensional NMR. Structural homology with various glycoside hydrolases suggested that RpfB cleaved oligosaccharides. Biochemical studies indicate that a conserved active site glutamate is important for resuscitation activity. These data, as well as the presence of a clear binding pocket for a large molecule, indicate that oligosaccharide cleavage is probably the signal for revival from dormancy