An unprecedented two-fold nested super-polyrotaxane: sulfate-directed hierarchical polythreading assembly of uranyl polyrotaxane moieties

Energy Technology Data Exchange (ETDEWEB)

Mei, Lei; Wu, Qun-yan; Yuan, Li-yong; Wang, Lin; An, Shu-wen; Xie, Zhen-ni; Hu, Kong-qiu; Shi, Wei-qun [Laboratory of Nuclear Energy Chemistry and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China); Chai, Zhi-fang [Laboratory of Nuclear Energy Chemistry and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China); School of Radiological and Interdisciplinary Sciences and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou (China); Burns, Peter C. [Department of Chemistry and Biochemistry, University of Notre Dame, IN (United States)

2016-08-01

The hierarchical assembly of well-organized submoieties could lead to more complicated superstructures with intriguing properties. We describe herein an unprecedented polyrotaxane polythreading framework containing a two-fold nested super-polyrotaxane substructure, which was synthesized through a uranyl-directed hierarchical polythreading assembly of one-dimensional polyrotaxane chains and two-dimensional polyrotaxane networks. This special assembly mode actually affords a new way of supramolecular chemistry instead of covalently linked bulky stoppers to construct stable interlocked rotaxane moieties. An investigation of the synthesis condition shows that sulfate can assume a vital role in mediating the formation of different uranyl species, especially the unique trinuclear uranyl moiety [(UO{sub 2}){sub 3}O(OH){sub 2}]{sup 2+}, involving a notable bent [O=U=O] bond with a bond angle of 172.0(9) . Detailed analysis of the coordination features, the thermal stability as well as a fluorescence, and electrochemical characterization demonstrate that the uniqueness of this super-polyrotaxane structure is mainly closely related to the trinuclear uranyl moiety, which is confirmed by quantum chemical calculations. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Printing, folding and assembly methods for forming 3D mesostructures in advanced materials

Science.gov (United States)

Zhang, Yihui; Zhang, Fan; Yan, Zheng; Ma, Qiang; Li, Xiuling; Huang, Yonggang; Rogers, John A.

2017-03-01

A rapidly expanding area of research in materials science involves the development of routes to complex 3D structures with feature sizes in the mesoscopic range (that is, between tens of nanometres and hundreds of micrometres). A goal is to establish methods for controlling the properties of materials systems and the function of devices constructed with them, not only through chemistry and morphology, but also through 3D architectures. The resulting systems, sometimes referred to as metamaterials, offer engineered behaviours with optical, thermal, acoustic, mechanical and electronic properties that do not occur in the natural world. Impressive advances in 3D printing techniques represent some of the most broadly recognized developments in this field, but recent successes with strategies based on concepts in origami, kirigami and deterministic assembly provide additional, unique options in 3D design and high-performance materials. In this Review, we highlight the latest progress and trends in methods for fabricating 3D mesostructures, beginning with the development of advanced material inks for nozzle-based approaches to 3D printing and new schemes for 3D optical patterning. In subsequent sections, we summarize more recent methods based on folding, rolling and mechanical assembly, including their application with materials such as designer hydrogels, monocrystalline inorganic semiconductors and graphene.

Directing folding pathways for multi-component DNA origami nanostructures with complex topology

International Nuclear Information System (INIS)

Marras, A E; Zhou, L; Su, H-J; Castro, C E; Kolliopoulos, V

2016-01-01

Molecular self-assembly has become a well-established technique to design complex nanostructures and hierarchical mesoscale assemblies. The typical approach is to design binding complementarity into nucleotide or amino acid sequences to achieve the desired final geometry. However, with an increasing interest in dynamic nanodevices, the need to design structures with motion has necessitated the development of multi-component structures. While this has been achieved through hierarchical assembly of similar structural units, here we focus on the assembly of topologically complex structures, specifically with concentric components, where post-folding assembly is not feasible. We exploit the ability to direct folding pathways to program the sequence of assembly and present a novel approach of designing the strand topology of intermediate folding states to program the topology of the final structure, in this case a DNA origami slider structure that functions much like a piston-cylinder assembly in an engine. The ability to program the sequence and control orientation and topology of multi-component DNA origami nanostructures provides a foundation for a new class of structures with internal and external moving parts and complex scaffold topology. Furthermore, this work provides critical insight to guide the design of intermediate states along a DNA origami folding pathway and to further understand the details of DNA origami self-assembly to more broadly control folding states and landscapes. (paper)

Directing folding pathways for multi-component DNA origami nanostructures with complex topology

Science.gov (United States)

Marras, A. E.; Zhou, L.; Kolliopoulos, V.; Su, H.-J.; Castro, C. E.

2016-05-01

Molecular self-assembly has become a well-established technique to design complex nanostructures and hierarchical mesoscale assemblies. The typical approach is to design binding complementarity into nucleotide or amino acid sequences to achieve the desired final geometry. However, with an increasing interest in dynamic nanodevices, the need to design structures with motion has necessitated the development of multi-component structures. While this has been achieved through hierarchical assembly of similar structural units, here we focus on the assembly of topologically complex structures, specifically with concentric components, where post-folding assembly is not feasible. We exploit the ability to direct folding pathways to program the sequence of assembly and present a novel approach of designing the strand topology of intermediate folding states to program the topology of the final structure, in this case a DNA origami slider structure that functions much like a piston-cylinder assembly in an engine. The ability to program the sequence and control orientation and topology of multi-component DNA origami nanostructures provides a foundation for a new class of structures with internal and external moving parts and complex scaffold topology. Furthermore, this work provides critical insight to guide the design of intermediate states along a DNA origami folding pathway and to further understand the details of DNA origami self-assembly to more broadly control folding states and landscapes.

FOLD-EM: automated fold recognition in medium- and low-resolution (4-15 Å) electron density maps.

Science.gov (United States)

Saha, Mitul; Morais, Marc C

2012-12-15

Owing to the size and complexity of large multi-component biological assemblies, the most tractable approach to determining their atomic structure is often to fit high-resolution radiographic or nuclear magnetic resonance structures of isolated components into lower resolution electron density maps of the larger assembly obtained using cryo-electron microscopy (cryo-EM). This hybrid approach to structure determination requires that an atomic resolution structure of each component, or a suitable homolog, is available. If neither is available, then the amount of structural information regarding that component is limited by the resolution of the cryo-EM map. However, even if a suitable homolog cannot be identified using sequence analysis, a search for structural homologs should still be performed because structural homology often persists throughout evolution even when sequence homology is undetectable, As macromolecules can often be described as a collection of independently folded domains, one way of searching for structural homologs would be to systematically fit representative domain structures from a protein domain database into the medium/low resolution cryo-EM map and return the best fits. Taken together, the best fitting non-overlapping structures would constitute a 'mosaic' backbone model of the assembly that could aid map interpretation and illuminate biological function. Using the computational principles of the Scale-Invariant Feature Transform (SIFT), we have developed FOLD-EM-a computational tool that can identify folded macromolecular domains in medium to low resolution (4-15 Å) electron density maps and return a model of the constituent polypeptides in a fully automated fashion. As a by-product, FOLD-EM can also do flexible multi-domain fitting that may provide insight into conformational changes that occur in macromolecular assemblies.

Proteins evolve on the edge of supramolecular self-assembly

Science.gov (United States)

Garcia-Seisdedos, Hector; Empereur-Mot, Charly; Elad, Nadav; Levy, Emmanuel D.

2017-08-01

The self-association of proteins into symmetric complexes is ubiquitous in all kingdoms of life. Symmetric complexes possess unique geometric and functional properties, but their internal symmetry can pose a risk. In sickle-cell disease, the symmetry of haemoglobin exacerbates the effect of a mutation, triggering assembly into harmful fibrils. Here we examine the universality of this mechanism and its relation to protein structure geometry. We introduced point mutations solely designed to increase surface hydrophobicity among 12 distinct symmetric complexes from Escherichia coli. Notably, all responded by forming supramolecular assemblies in vitro, as well as in vivo upon heterologous expression in Saccharomyces cerevisiae. Remarkably, in four cases, micrometre-long fibrils formed in vivo in response to a single point mutation. Biophysical measurements and electron microscopy revealed that mutants self-assembled in their folded states and so were not amyloid-like. Structural examination of 73 mutants identified supramolecular assembly hot spots predictable by geometry. A subsequent structural analysis of 7,471 symmetric complexes showed that geometric hot spots were buffered chemically by hydrophilic residues, suggesting a mechanism preventing mis-assembly of these regions. Thus, point mutations can frequently trigger folded proteins to self-assemble into higher-order structures. This potential is counterbalanced by negative selection and can be exploited to design nanomaterials in living cells.

Bifurcation of self-folded polygonal bilayers

Science.gov (United States)

Abdullah, Arif M.; Braun, Paul V.; Hsia, K. Jimmy

2017-09-01

Motivated by the self-assembly of natural systems, researchers have investigated the stimulus-responsive curving of thin-shell structures, which is also known as self-folding. Self-folding strategies not only offer possibilities to realize complicated shapes but also promise actuation at small length scales. Biaxial mismatch strain driven self-folding bilayers demonstrate bifurcation of equilibrium shapes (from quasi-axisymmetric doubly curved to approximately singly curved) during their stimulus-responsive morphing behavior. Being a structurally instable, bifurcation could be used to tune the self-folding behavior, and hence, a detailed understanding of this phenomenon is appealing from both fundamental and practical perspectives. In this work, we investigated the bifurcation behavior of self-folding bilayer polygons. For the mechanistic understanding, we developed finite element models of planar bilayers (consisting of a stimulus-responsive and a passive layer of material) that transform into 3D curved configurations. Our experiments with cross-linked Polydimethylsiloxane samples that change shapes in organic solvents confirmed our model predictions. Finally, we explored a design scheme to generate gripper-like architectures by avoiding the bifurcation of stimulus-responsive bilayers. Our research contributes to the broad field of self-assembly as the findings could motivate functional devices across multiple disciplines such as robotics, artificial muscles, therapeutic cargos, and reconfigurable biomedical devices.

Expression and distribution of hyaluronic acid and CD44 in unphonated human vocal fold mucosa.

Science.gov (United States)

Sato, Kiminori; Umeno, Hirohito; Nakashima, Tadashi; Nonaka, Satoshi; Harabuchi, Yasuaki

2009-11-01

The tension caused by phonation (vocal fold vibration) is hypothesized to stimulate vocal fold stellate cells (VFSCs) in the maculae flavae (MFe) to accelerate production of extracellular matrices. The distribution of hyaluronic acid (HA) and expression of CD44 (a cell surface receptor for HA) were examined in human vocal fold mucosae (VFMe) that had remained unphonated since birth. Five specimens of VFMe (3 adults, 2 children) that had remained unphonated since birth were investigated with Alcian blue staining, hyaluronidase digestion, and immunohistochemistry for CD44. The VFMe containing MFe were hypoplastic and rudimentary. The VFMe did not have a vocal ligament, Reinke's space, or a layered structure, and the lamina propria appeared as a uniform structure. In the children, HA was distributed in the VFMe containing MFe. In the adults, HA had decreased in the VFMe containing MFe. In both groups, the VFSCs in the MFe and the fibroblasts in the lamina propria expressed little CD44. This study supports the hypothesis that the tensions caused by vocal fold vibration stimulate the VFSCs in the MFe to accelerate production of extracellular matrices and form the layered structure. Phonation after birth is one of the important factors in the growth and development of the human VFMe.

Validation of differential gene expression algorithms: Application comparing fold-change estimation to hypothesis testing

Directory of Open Access Journals (Sweden)

Bickel David R

2010-01-01

Full Text Available Abstract Background Sustained research on the problem of determining which genes are differentially expressed on the basis of microarray data has yielded a plethora of statistical algorithms, each justified by theory, simulation, or ad hoc validation and yet differing in practical results from equally justified algorithms. Recently, a concordance method that measures agreement among gene lists have been introduced to assess various aspects of differential gene expression detection. This method has the advantage of basing its assessment solely on the results of real data analyses, but as it requires examining gene lists of given sizes, it may be unstable. Results Two methodologies for assessing predictive error are described: a cross-validation method and a posterior predictive method. As a nonparametric method of estimating prediction error from observed expression levels, cross validation provides an empirical approach to assessing algorithms for detecting differential gene expression that is fully justified for large numbers of biological replicates. Because it leverages the knowledge that only a small portion of genes are differentially expressed, the posterior predictive method is expected to provide more reliable estimates of algorithm performance, allaying concerns about limited biological replication. In practice, the posterior predictive method can assess when its approximations are valid and when they are inaccurate. Under conditions in which its approximations are valid, it corroborates the results of cross validation. Both comparison methodologies are applicable to both single-channel and dual-channel microarrays. For the data sets considered, estimating prediction error by cross validation demonstrates that empirical Bayes methods based on hierarchical models tend to outperform algorithms based on selecting genes by their fold changes or by non-hierarchical model-selection criteria. (The latter two approaches have comparable

An Improved Genome Assembly of Azadirachta indica A. Juss.

Directory of Open Access Journals (Sweden)

Neeraja M. Krishnan

2016-07-01

Full Text Available Neem (Azadirachta indica A. Juss., an evergreen tree of the Meliaceae family, is known for its medicinal, cosmetic, pesticidal and insecticidal properties. We had previously sequenced and published the draft genome of a neem plant, using mainly short read sequencing data. In this report, we present an improved genome assembly generated using additional short reads from Illumina and long reads from Pacific Biosciences SMRT sequencer. We assembled short reads and error-corrected long reads using Platanus, an assembler designed to perform well for heterozygous genomes. The updated genome assembly (v2.0 yielded 3- and 3.5-fold increase in N50 and N75, respectively; 2.6-fold decrease in the total number of scaffolds; 1.25-fold increase in the number of valid transcriptome alignments; 13.4-fold less misassembly and 1.85-fold increase in the percentage repeat, over the earlier assembly (v1.0. The current assembly also maps better to the genes known to be involved in the terpenoid biosynthesis pathway. Together, the data represent an improved assembly of the A. indica genome.

100-fold but not 50-fold dystrophin overexpression aggravates electrocardiographic defects in the mdx model of Duchenne muscular dystrophy

Directory of Open Access Journals (Sweden)

Yongping Yue

2016-01-01

Full Text Available Dystrophin gene replacement holds the promise of treating Duchenne muscular dystrophy. Supraphysiological expression is a concern for all gene therapy studies. In the case of Duchenne muscular dystrophy, Chamberlain and colleagues found that 50-fold overexpression did not cause deleterious side effect in skeletal muscle. To determine whether excessive dystrophin expression in the heart is safe, we studied two lines of transgenic mdx mice that selectively expressed a therapeutic minidystrophin gene in the heart at 50-fold and 100-fold of the normal levels. In the line with 50-fold overexpression, minidystrophin showed sarcolemmal localization and electrocardiogram abnormalities were corrected. However, in the line with 100-fold overexpression, we not only detected sarcolemmal minidystrophin expression but also observed accumulation of minidystrophin vesicles in the sarcoplasm. Excessive minidystrophin expression did not correct tachycardia, a characteristic feature of Duchenne muscular dystrophy. Importantly, several electrocardiogram parameters (QT interval, QRS duration and the cardiomyopathy index became worse than that of mdx mice. Our data suggests that the mouse heart can tolerate 50-fold minidystrophin overexpression, but 100-fold overexpression leads to cardiac toxicity.

Pentameric ligand-gated ion channels exhibit distinct transmembrane domain archetypes for folding/expression and function.

Science.gov (United States)

Therien, J P Daniel; Baenziger, John E

2017-03-27

Although transmembrane helix-helix interactions must be strong enough to drive folding, they must still permit the inter-helix movements associated with conformational change. Interactions between the outermost M4 and adjacent M1 and M3 α-helices of pentameric ligand-gated ion channels have been implicated in folding and function. Here, we evaluate the role of different physical interactions at this interface in the function of two prokaryotic homologs, GLIC and ELIC. Strikingly, disruption of most interactions in GLIC lead to either a reduction or a complete loss of expression and/or function, while analogous disruptions in ELIC often lead to gains in function. Structural comparisons suggest that GLIC and ELIC represent distinct transmembrane domain archetypes. One archetype, exemplified by GLIC, the glycine and GABA receptors and the glutamate activated chloride channel, has extensive aromatic contacts that govern M4-M1/M3 interactions and that are essential for expression and function. The other archetype, exemplified by ELIC and both the nicotinic acetylcholine and serotonin receptors, has relatively few aromatic contacts that are detrimental to function. These archetypes likely have evolved different mechanisms to balance the need for strong M4 "binding" to M1/M3 to promote folding/expression, and the need for weaker interactions that allow for greater conformational flexibility.

Expression, purification and insights into structure and folding of the ADAM22 pro domain

DEFF Research Database (Denmark)

Sørensen, Hans Peter; Jacobsen, Jonas; Nielbo, Steen

2008-01-01

. To understand the functions of human ADAM pro domains and to determine three-dimensional structures, we have screened promising targets for expression and purification properties when using Escherichia coli as the host. The pro domain of ADAM22 (ADAM22-P) expressed in E. coli was folded, as determined by CD...... and NMR spectroscopy. An ADAM22-P fragment encoding residues 26-199 could be expressed in high amounts, remained soluble above 1 mM, and was suitable for structural studies by NMR spectroscopy. CD spectroscopy and predictions suggest that the secondary structure in ADAM22-P consists of beta...

Computational design of RNA parts, devices, and transcripts with kinetic folding algorithms implemented on multiprocessor clusters.

Science.gov (United States)

Thimmaiah, Tim; Voje, William E; Carothers, James M

2015-01-01

With progress toward inexpensive, large-scale DNA assembly, the demand for simulation tools that allow the rapid construction of synthetic biological devices with predictable behaviors continues to increase. By combining engineered transcript components, such as ribosome binding sites, transcriptional terminators, ligand-binding aptamers, catalytic ribozymes, and aptamer-controlled ribozymes (aptazymes), gene expression in bacteria can be fine-tuned, with many corollaries and applications in yeast and mammalian cells. The successful design of genetic constructs that implement these kinds of RNA-based control mechanisms requires modeling and analyzing kinetically determined co-transcriptional folding pathways. Transcript design methods using stochastic kinetic folding simulations to search spacer sequence libraries for motifs enabling the assembly of RNA component parts into static ribozyme- and dynamic aptazyme-regulated expression devices with quantitatively predictable functions (rREDs and aREDs, respectively) have been described (Carothers et al., Science 334:1716-1719, 2011). Here, we provide a detailed practical procedure for computational transcript design by illustrating a high throughput, multiprocessor approach for evaluating spacer sequences and generating functional rREDs. This chapter is written as a tutorial, complete with pseudo-code and step-by-step instructions for setting up a computational cluster with an Amazon, Inc. web server and performing the large numbers of kinefold-based stochastic kinetic co-transcriptional folding simulations needed to design functional rREDs and aREDs. The method described here should be broadly applicable for designing and analyzing a variety of synthetic RNA parts, devices and transcripts.

Impaired folding and subunit assembly as disease mechanism

DEFF Research Database (Denmark)

Bross, P; Andresen, B S; Gregersen, N

1998-01-01

folding is a common effect of missense mutations occurring in genetic diseases, (ii) increasing the level of available chaperones may augment the level of functional mutant protein in vivo, and (iii) one mutation may have multiple effects. The interplay between the chaperones assisting folding......Rapid progress in DNA technology has entailed the possibility of readily detecting mutations in disease genes. In contrast to this, techniques to characterize the effects of mutations are still very time consuming. It has turned out that many of the mutations detected in disease genes are missense...... mutations. Characterization of the effect of these mutations is particularly important in order to establish that they are disease causing and to estimate their severity. We use the experiences with investigation of medium-chain acyl-CoA dehydrogenase deficiency as an example to illustrate that (i) impaired...

Synthetic oligorotaxanes exert high forces when folding under mechanical load

Science.gov (United States)

Sluysmans, Damien; Hubert, Sandrine; Bruns, Carson J.; Zhu, Zhixue; Stoddart, J. Fraser; Duwez, Anne-Sophie

2018-01-01

Folding is a ubiquitous process that nature uses to control the conformations of its molecular machines, allowing them to perform chemical and mechanical tasks. Over the years, chemists have synthesized foldamers that adopt well-defined and stable folded architectures, mimicking the control expressed by natural systems1,2. Mechanically interlocked molecules, such as rotaxanes and catenanes, are prototypical molecular machines that enable the controlled movement and positioning of their component parts3-5. Recently, combining the exquisite complexity of these two classes of molecules, donor-acceptor oligorotaxane foldamers have been synthesized, in which interactions between the mechanically interlocked component parts dictate the single-molecule assembly into a folded secondary structure6-8. Here we report on the mechanochemical properties of these molecules. We use atomic force microscopy-based single-molecule force spectroscopy to mechanically unfold oligorotaxanes, made of oligomeric dumbbells incorporating 1,5-dioxynaphthalene units encircled by cyclobis(paraquat-p-phenylene) rings. Real-time capture of fluctuations between unfolded and folded states reveals that the molecules exert forces of up to 50 pN against a mechanical load of up to 150 pN, and displays transition times of less than 10 μs. While the folding is at least as fast as that observed in proteins, it is remarkably more robust, thanks to the mechanically interlocked structure. Our results show that synthetic oligorotaxanes have the potential to exceed the performance of natural folding proteins.

Building polyhedra by self-assembly: theory and experiment.

Science.gov (United States)

Kaplan, Ryan; Klobušický, Joseph; Pandey, Shivendra; Gracias, David H; Menon, Govind

2014-01-01

We investigate the utility of a mathematical framework based on discrete geometry to model biological and synthetic self-assembly. Our primary biological example is the self-assembly of icosahedral viruses; our synthetic example is surface-tension-driven self-folding polyhedra. In both instances, the process of self-assembly is modeled by decomposing the polyhedron into a set of partially formed intermediate states. The set of all intermediates is called the configuration space, pathways of assembly are modeled as paths in the configuration space, and the kinetics and yield of assembly are modeled by rate equations, Markov chains, or cost functions on the configuration space. We review an interesting interplay between biological function and mathematical structure in viruses in light of this framework. We discuss in particular: (i) tiling theory as a coarse-grained description of all-atom models; (ii) the building game-a growth model for the formation of polyhedra; and (iii) the application of these models to the self-assembly of the bacteriophage MS2. We then use a similar framework to model self-folding polyhedra. We use a discrete folding algorithm to compute a configuration space that idealizes surface-tension-driven self-folding and analyze pathways of assembly and dominant intermediates. These computations are then compared with experimental observations of a self-folding dodecahedron with side 300 μm. In both models, despite a combinatorial explosion in the size of the configuration space, a few pathways and intermediates dominate self-assembly. For self-folding polyhedra, the dominant intermediates have fewer degrees of freedom than comparable intermediates, and are thus more rigid. The concentration of assembly pathways on a few intermediates with distinguished geometric properties is biologically and physically important, and suggests deeper mathematical structure.

Self-folding polymeric containers for encapsulation and delivery of drugs.

Science.gov (United States)

Fernandes, Rohan; Gracias, David H

2012-11-01

Self-folding broadly refers to self-assembly processes wherein thin films or interconnected planar templates curve, roll-up or fold into three dimensional (3D) structures such as cylindrical tubes, spirals, corrugated sheets or polyhedra. The process has been demonstrated with metallic, semiconducting and polymeric films and has been used to curve tubes with diameters as small as 2nm and fold polyhedra as small as 100nm, with a surface patterning resolution of 15nm. Self-folding methods are important for drug delivery applications since they provide a means to realize 3D, biocompatible, all-polymeric containers with well-tailored composition, size, shape, wall thickness, porosity, surface patterns and chemistry. Self-folding is also a highly parallel process, and it is possible to encapsulate or self-load therapeutic cargo during assembly. A variety of therapeutic cargos such as small molecules, peptides, proteins, bacteria, fungi and mammalian cells have been encapsulated in self-folded polymeric containers. In this review, we focus on self-folding of all-polymeric containers. We discuss the mechanistic aspects of self-folding of polymeric containers driven by differential stresses or surface tension forces, the applications of self-folding polymers in drug delivery and we outline future challenges. Copyright © 2012 Elsevier B.V. All rights reserved.

1.8 Å structure of murine GITR ligand dimer expressed in Drosophila melanogaster S2 cells

International Nuclear Information System (INIS)

Chattopadhyay, Kausik; Ramagopal, Udupi A.; Nathenson, Stanley G.; Almo, Steven C.

2009-01-01

1.8 Å X-ray crystal structure of mouse GITRL expressed in D. melanogaster S2 cells shows an identical ‘strand-exchanged’ dimeric assembly similar to that observed previously for the E. coli-expressed protein. Glucocorticoid-induced TNF receptor ligand (GITRL), a prominent member of the TNF superfamily, activates its receptor on both effector and regulatory T cells to generate critical costimulatory signals that have been implicated in a wide range of T-cell immune functions. The crystal structures of murine and human orthologs of GITRL recombinantly expressed in Escherichia coli have previously been determined. In contrast to all classical TNF structures, including the human GITRL structure, murine GITRL demonstrated a unique ‘strand-exchanged’ dimeric organization. Such a novel assembly behavior indicated a dramatic impact on receptor activation as well as on the signaling mechanism associated with the murine GITRL costimulatory system. In this present work, the 1.8 Å resolution crystal structure of murine GITRL expressed in Drosophila melanogaster S2 cells is reported. The eukaryotic protein-expression system allows transport of the recombinant protein into the extracellular culture medium, thus maximizing the possibility of obtaining correctly folded material devoid of any folding/assembly artifacts that are often suspected with E. coli-expressed proteins. The S2 cell-expressed murine GITRL adopts an identical ‘strand-exchanged’ dimeric structure to that observed for the E. coli-expressed protein, thus conclusively demonstrating the novel quaternary structure assembly behavior of murine GITRL

1.8 Å structure of murine GITR ligand dimer expressed in Drosophila melanogaster S2 cells

Energy Technology Data Exchange (ETDEWEB)

Chattopadhyay, Kausik [Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Ramagopal, Udupi A. [Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Nathenson, Stanley G., E-mail: nathenso@aecom.yu.edu [Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Almo, Steven C., E-mail: nathenso@aecom.yu.edu [Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461 (United States)

2009-05-01

1.8 Å X-ray crystal structure of mouse GITRL expressed in D. melanogaster S2 cells shows an identical ‘strand-exchanged’ dimeric assembly similar to that observed previously for the E. coli-expressed protein. Glucocorticoid-induced TNF receptor ligand (GITRL), a prominent member of the TNF superfamily, activates its receptor on both effector and regulatory T cells to generate critical costimulatory signals that have been implicated in a wide range of T-cell immune functions. The crystal structures of murine and human orthologs of GITRL recombinantly expressed in Escherichia coli have previously been determined. In contrast to all classical TNF structures, including the human GITRL structure, murine GITRL demonstrated a unique ‘strand-exchanged’ dimeric organization. Such a novel assembly behavior indicated a dramatic impact on receptor activation as well as on the signaling mechanism associated with the murine GITRL costimulatory system. In this present work, the 1.8 Å resolution crystal structure of murine GITRL expressed in Drosophila melanogaster S2 cells is reported. The eukaryotic protein-expression system allows transport of the recombinant protein into the extracellular culture medium, thus maximizing the possibility of obtaining correctly folded material devoid of any folding/assembly artifacts that are often suspected with E. coli-expressed proteins. The S2 cell-expressed murine GITRL adopts an identical ‘strand-exchanged’ dimeric structure to that observed for the E. coli-expressed protein, thus conclusively demonstrating the novel quaternary structure assembly behavior of murine GITRL.

EMMA: An Extensible Mammalian Modular Assembly Toolkit for the Rapid Design and Production of Diverse Expression Vectors.

Science.gov (United States)

Martella, Andrea; Matjusaitis, Mantas; Auxillos, Jamie; Pollard, Steven M; Cai, Yizhi

2017-07-21

Mammalian plasmid expression vectors are critical reagents underpinning many facets of research across biology, biomedical research, and the biotechnology industry. Traditional cloning methods often require laborious manual design and assembly of plasmids using tailored sequential cloning steps. This process can be protracted, complicated, expensive, and error-prone. New tools and strategies that facilitate the efficient design and production of bespoke vectors would help relieve a current bottleneck for researchers. To address this, we have developed an extensible mammalian modular assembly kit (EMMA). This enables rapid and efficient modular assembly of mammalian expression vectors in a one-tube, one-step golden-gate cloning reaction, using a standardized library of compatible genetic parts. The high modularity, flexibility, and extensibility of EMMA provide a simple method for the production of functionally diverse mammalian expression vectors. We demonstrate the value of this toolkit by constructing and validating a range of representative vectors, such as transient and stable expression vectors (transposon based vectors), targeting vectors, inducible systems, polycistronic expression cassettes, fusion proteins, and fluorescent reporters. The method also supports simple assembly combinatorial libraries and hierarchical assembly for production of larger multigenetic cargos. In summary, EMMA is compatible with automated production, and novel genetic parts can be easily incorporated, providing new opportunities for mammalian synthetic biology.

Enhanced cellular immune response against SIV Gag induced by immunization with DNA vaccines expressing assembly and release-defective SIV Gag proteins

International Nuclear Information System (INIS)

Bu Zhigao; Ye Ling; Compans, Richard W.; Yang Chinglai

2003-01-01

Codon-optimized genes were synthesized for the SIVmac239 Gag, a mutant Gag with mutations in the major homology region, and a chimeric Gag containing a protein destruction signal at the N-terminus of Gag. The mutant and chimeric Gag were expressed at levels comparable to that observed for the wild-type Gag protein but their stability and release into the medium were found to be significantly reduced. Immunization of mice with DNA vectors encoding the mutant or chimeric Gag induced fourfold higher levels of anti-SIV Gag CD4 T cell responses than the DNA vector encoding the wild-type SIV Gag. Moreover, anti-SIV Gag CD8 T cell responses induced by DNA vectors encoding the mutant or chimeric Gag were found to be 5- to 10-fold higher than those induced by the DNA construct for the wild-type Gag. These results indicate that mutations disrupting assembly and/or stability of the SIV Gag protein effectively enhance its immunogenicity when expressed from DNA vaccines

A versatile system for USER cloning-based assembly of expression vectors for mammalian cell engineering.

Directory of Open Access Journals (Sweden)

Anne Mathilde Lund

Full Text Available A new versatile mammalian vector system for protein production, cell biology analyses, and cell factory engineering was developed. The vector system applies the ligation-free uracil-excision based technique--USER cloning--to rapidly construct mammalian expression vectors of multiple DNA fragments and with maximum flexibility, both for choice of vector backbone and cargo. The vector system includes a set of basic vectors and a toolbox containing a multitude of DNA building blocks including promoters, terminators, selectable marker- and reporter genes, and sequences encoding an internal ribosome entry site, cellular localization signals and epitope- and purification tags. Building blocks in the toolbox can be easily combined as they contain defined and tested Flexible Assembly Sequence Tags, FASTs. USER cloning with FASTs allows rapid swaps of gene, promoter or selection marker in existing plasmids and simple construction of vectors encoding proteins, which are fused to fluorescence-, purification-, localization-, or epitope tags. The mammalian expression vector assembly platform currently allows for the assembly of up to seven fragments in a single cloning step with correct directionality and with a cloning efficiency above 90%. The functionality of basic vectors for FAST assembly was tested and validated by transient expression of fluorescent model proteins in CHO, U-2-OS and HEK293 cell lines. In this test, we included many of the most common vector elements for heterologous gene expression in mammalian cells, in addition the system is fully extendable by other users. The vector system is designed to facilitate high-throughput genome-scale studies of mammalian cells, such as the newly sequenced CHO cell lines, through the ability to rapidly generate high-fidelity assembly of customizable gene expression vectors.

IDBA-tran: a more robust de novo de Bruijn graph assembler for transcriptomes with uneven expression levels.

Science.gov (United States)

Peng, Yu; Leung, Henry C M; Yiu, Siu-Ming; Lv, Ming-Ju; Zhu, Xin-Guang; Chin, Francis Y L

2013-07-01

RNA sequencing based on next-generation sequencing technology is effective for analyzing transcriptomes. Like de novo genome assembly, de novo transcriptome assembly does not rely on any reference genome or additional annotation information, but is more difficult. In particular, isoforms can have very uneven expression levels (e.g. 1:100), which make it very difficult to identify low-expressed isoforms. One challenge is to remove erroneous vertices/edges with high multiplicity (produced by high-expressed isoforms) in the de Bruijn graph without removing correct ones with not-so-high multiplicity from low-expressed isoforms. Failing to do so will result in the loss of low-expressed isoforms or having complicated subgraphs with transcripts of different genes mixed together due to erroneous vertices/edges. Contributions: Unlike existing tools, which remove erroneous vertices/edges with multiplicities lower than a global threshold, we use a probabilistic progressive approach to iteratively remove them with local thresholds. This enables us to decompose the graph into disconnected components, each containing a few genes, if not a single gene, while retaining many correct vertices/edges of low-expressed isoforms. Combined with existing techniques, IDBA-Tran is able to assemble both high-expressed and low-expressed transcripts and outperform existing assemblers in terms of sensitivity and specificity for both simulated and real data. http://www.cs.hku.hk/~alse/idba_tran. Supplementary data are available at Bioinformatics online.

Light-activated control of protein channel assembly mediated by membrane mechanics

Science.gov (United States)

Miller, David M.; Findlay, Heather E.; Ces, Oscar; Templer, Richard H.; Booth, Paula J.

2016-12-01

Photochemical processes provide versatile triggers of chemical reactions. Here, we use a photoactivated lipid switch to modulate the folding and assembly of a protein channel within a model biological membrane. In contrast to the information rich field of water-soluble protein folding, there is only a limited understanding of the assembly of proteins that are integral to biological membranes. It is however possible to exploit the foreboding hydrophobic lipid environment and control membrane protein folding via lipid bilayer mechanics. Mechanical properties such as lipid chain lateral pressure influence the insertion and folding of proteins in membranes, with different stages of folding having contrasting sensitivities to the bilayer properties. Studies to date have relied on altering bilayer properties through lipid compositional changes made at equilibrium, and thus can only be made before or after folding. We show that light-activation of photoisomerisable di-(5-[[4-(4-butylphenyl)azo]phenoxy]pentyl)phosphate (4-Azo-5P) lipids influences the folding and assembly of the pentameric bacterial mechanosensitive channel MscL. The use of a photochemical reaction enables the bilayer properties to be altered during folding, which is unprecedented. This mechanical manipulation during folding, allows for optimisation of different stages of the component insertion, folding and assembly steps within the same lipid system. The photochemical approach offers the potential to control channel assembly when generating synthetic devices that exploit the mechanosensitive protein as a nanovalve.

Expression and assembly of largest foreign protein in chloroplasts: oral delivery of human FVIII made in lettuce chloroplasts robustly suppresses inhibitor formation in haemophilia A mice.

Science.gov (United States)

Kwon, Kwang-Chul; Sherman, Alexandra; Chang, Wan-Jung; Kamesh, Aditya; Biswas, Moanaro; Herzog, Roland W; Daniell, Henry

2017-11-06

Inhibitor formation is a serious complication of factor VIII (FVIII) replacement therapy for the X-linked bleeding disorder haemophilia A and occurs in 20%-30% of patients. No prophylactic tolerance protocol currently exists. Although we reported oral tolerance induction using FVIII domains expressed in tobacco chloroplasts, significant challenges in clinical advancement include expression of the full-length CTB-FVIII sequence to cover the entire patient population, regardless of individual CD4 + T-cell epitope responses. Codon optimization of FVIII heavy chain (HC) and light chain (LC) increased expression 15- to 42-fold higher than the native human genes. Homoplasmic lettuce lines expressed CTB fusion proteins of FVIII-HC (99.3 kDa), LC (91.8 kDa), C2 (31 kDa) or single chain (SC, 178.2 kDa) up to 3622, 263, 3321 and 852 μg/g in lyophilized plant cells, when grown in a cGMP hydroponic facility (Fraunhofer). CTB-FVIII-SC is the largest foreign protein expressed in chloroplasts; despite a large pentamer size (891 kDa), assembly, folding and disulphide bonds were maintained upon lyophilization and long-term storage as revealed by GM1-ganglioside receptor binding assays. Repeated oral gavages (twice/week for 2 months) of CTB-FVIII-HC/CTB-FVIII-LC reduced inhibitor titres ~10-fold (average 44 BU/mL to 4.7 BU/mL) in haemophilia A mice. Most importantly, increase in the frequency of circulating LAP-expressing CD4 + CD25 + FoxP3 + Treg in tolerized mice could be used as an important cellular biomarker in human clinical trials for plant-based oral tolerance induction. In conclusion, this study reports the first clinical candidate for oral tolerance induction that is urgently needed to protect haemophilia A patients receiving FVIII injections. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Cytochrome oxidase assembly does not require catalytically active cytochrome C.

Science.gov (United States)

Barrientos, Antoni; Pierre, Danielle; Lee, Johnson; Tzagoloff, Alexander

2003-03-14

Cytochrome c oxidase (COX), the terminal enzyme of the mitochondrial respiratory chain, catalyzes the transfer of electrons from reduced cytochrome c to molecular oxygen. COX assembly requires the coming together of nuclear- and mitochondrial-encoded subunits and the assistance of a large number of nuclear gene products acting at different stages of maturation of the enzyme. In Saccharomyces cerevisiae, expression of cytochrome c, encoded by CYC1 and CYC7, is required not only for electron transfer but also for COX assembly through a still unknown mechanism. We have attempted to distinguish between a functional and structural requirement of cytochrome c in COX assembly. A cyc1/cyc7 double null mutant strain was transformed with the cyc1-166 mutant gene (Schweingruber, M. E., Stewart, J. W., and Sherman, F. (1979) J. Biol. Chem. 254, 4132-4143) that expresses stable but catalytically inactive iso-1-cytochrome c. The COX content of the cyc1/cyc7 double mutant strain harboring non-functional iso-1-cytochrome c has been characterized spectrally, functionally, and immunochemically. The results of these studies demonstrate that cytochrome c plays a structural rather than functional role in assembly of cytochrome c oxidase. In addition to its requirement for COX assembly, cytochrome c also affects turnover of the enzyme. Mutants containing wild type apocytochrome c in mitochondria lack COX, suggesting that only the folded and mature protein is able to promote COX assembly.

Evaluating Perceived Naturalness of Facial Expression After Fillers to the Nasolabial Folds and Lower Face With Standardized Video and Photography.

Science.gov (United States)

Philipp-Dormston, Wolfgang G; Wong, Cindy; Schuster, Bernd; Larsson, Markus K; Podda, Maurizio

2018-06-01

Hyaluronic acid (HA) fillers are commonly used in treating facial wrinkles and folds but have not been studied with standardized methodology to include assessment of standard facial expressions. To assess perceived naturalness of facial expression after treatment with 2 HA fillers manufactured with XpresHAn Technology (also known as Optimal Balance Technology). Treatment was directed to the nasolabial folds (NLFs) and at least 1 additional lower face wrinkle or fold. Maintenance of naturalness, attractiveness, and age at 1 month after optimal treatment were assessed using video recordings and photographs capturing different facial animations. Global aesthetic improvement, subjects' satisfaction, and safety were also evaluated. The treatment was well tolerated. Naturalness of facial expression in motion was determined to be at least maintained in 95% of subjects. Attractiveness was enhanced in 89% of subjects and 79% of subjects were considered to look younger. Most subjects assessed their aesthetic appearance as improved and were satisfied with their treatment. Naturalness and attractiveness can be assessed using video recordings and photographs capturing different facial animations. XpresHAn Technology HA filler treatments create natural-looking results with high subject satisfaction.

A YEAST SPECIFIC INSERTION AMIDST OBG FOLD IS CRITICAL FOR THE MITOCHONDRIAL FUNCTION OF Mtg2p IN SACCHAROMYCES CEREVISIAE

Directory of Open Access Journals (Sweden)

Upasana Mehra

2017-06-01

Full Text Available Protein expression in mitochondria is carried out by ribosomes that are distinct from their cytosolic counterpart. Mitochondrial ribosomes are made of individual proteins having distinct lineages: those with clear bacterial orthologues, those conserved in eukaryotes only and proteins that are species specific. MTG2 is the mitochondrial member of the universally conserved Obg family of GTPases in Saccharomyces cerevisiae which associates with and regulates mitochondrial large ribosomal subunit assembly. In this study we demonstrate that MTG2, in addition to the universally conserved OBG and GTPase domains, has an essential yeast specific insertion domain positioned within the N terminal OBG fold. Cells expressing mtg2∆201-294, deleted for the insertion domain are not able to support cellular respiration. In addition, we show that large stretches of amino acids can be inserted into MTG2 at the end of the yeast specific insertion domain and the OBG fold without perturbing its cellular functions, consistent with the insertion domain folding into a species specific protein binding platform.

An advanced draft genome assembly of a desi type chickpea (Cicer arietinum L.).

Science.gov (United States)

Parween, Sabiha; Nawaz, Kashif; Roy, Riti; Pole, Anil K; Venkata Suresh, B; Misra, Gopal; Jain, Mukesh; Yadav, Gitanjali; Parida, Swarup K; Tyagi, Akhilesh K; Bhatia, Sabhyata; Chattopadhyay, Debasis

2015-08-11

Chickpea (Cicer arietinum L.) is an important pulse legume crop. We previously reported a draft genome assembly of the desi chickpea cultivar ICC 4958. Here we report an advanced version of the ICC 4958 genome assembly (version 2.0) generated using additional sequence data and an improved genetic map. This resulted in 2.7-fold increase in the length of the pseudomolecules and substantial reduction of sequence gaps. The genome assembly covered more than 94% of the estimated gene space and predicted the presence of 30,257 protein-coding genes including 2230 and 133 genes encoding potential transcription factors (TF) and resistance gene homologs, respectively. Gene expression analysis identified several TF and chickpea-specific genes with tissue-specific expression and displayed functional diversification of the paralogous genes. Pairwise comparison of pseudomolecules in the desi (ICC 4958) and the earlier reported kabuli (CDC Frontier) chickpea assemblies showed an extensive local collinearity with incongruity in the placement of large sequence blocks along the linkage groups, apparently due to use of different genetic maps. Single nucleotide polymorphism (SNP)-based mining of intra-specific polymorphism identified more than four thousand SNPs differentiating a desi group and a kabuli group of chickpea genotypes.

An overview on molecular chaperones enhancing solubility of expressed recombinant proteins with correct folding.

Science.gov (United States)

Mamipour, Mina; Yousefi, Mohammadreza; Hasanzadeh, Mohammad

2017-09-01

The majority of research topics declared that most of the recombinant proteins have been expressed by Escherichia coli in basic investigations. But the majority of high expressed proteins formed as inactive recombinant proteins that are called inclusion body. To overcome this problem, several methods have been used including suitable promoter, environmental factors, ladder tag to secretion of proteins into the periplasm, gene protein optimization, chemical chaperones and molecular chaperones sets. Co-expression of the interest protein with molecular chaperones is one of the common methods The chaperones are a group of proteins, which are involved in making correct folding of recombinant proteins. Chaperones are divided two groups including; cytoplasmic and periplasmic chaperones. Moreover, periplasmic chaperones and proteases can be manipulated to increase the yields of secreted proteins. In this article, we attempted to review cytoplasmic chaperones such as Hsp families and periplasmic chaperones including; generic chaperones, specialized chaperones, PPIases, and proteins involved in disulfide bond formation. Copyright © 2017 Elsevier B.V. All rights reserved.

CASP10-BCL::Fold efficiently samples topologies of large proteins.

Science.gov (United States)

Heinze, Sten; Putnam, Daniel K; Fischer, Axel W; Kohlmann, Tim; Weiner, Brian E; Meiler, Jens

2015-03-01

During CASP10 in summer 2012, we tested BCL::Fold for prediction of free modeling (FM) and template-based modeling (TBM) targets. BCL::Fold assembles the tertiary structure of a protein from predicted secondary structure elements (SSEs) omitting more flexible loop regions early on. This approach enables the sampling of conformational space for larger proteins with more complex topologies. In preparation of CASP11, we analyzed the quality of CASP10 models throughout the prediction pipeline to understand BCL::Fold's ability to sample the native topology, identify native-like models by scoring and/or clustering approaches, and our ability to add loop regions and side chains to initial SSE-only models. The standout observation is that BCL::Fold sampled topologies with a GDT_TS score > 33% for 12 of 18 and with a topology score > 0.8 for 11 of 18 test cases de novo. Despite the sampling success of BCL::Fold, significant challenges still exist in clustering and loop generation stages of the pipeline. The clustering approach employed for model selection often failed to identify the most native-like assembly of SSEs for further refinement and submission. It was also observed that for some β-strand proteins model refinement failed as β-strands were not properly aligned to form hydrogen bonds removing otherwise accurate models from the pool. Further, BCL::Fold samples frequently non-natural topologies that require loop regions to pass through the center of the protein. © 2015 Wiley Periodicals, Inc.

Self-folding mechanics of graphene tearing and peeling from a substrate

Science.gov (United States)

He, Ze-Zhou; Zhu, Yin-Bo; Wu, Heng-An

2018-06-01

Understanding the underlying mechanism in the tearing and peeling processes of graphene is crucial for the further hierarchical design of origami-like folding and kirigami-like cutting of graphene. However, the complex effects among bending moduli, adhesion, interlayer interaction, and local crystal structure during origami-like folding and kirigami-like cutting remain unclear, resulting in challenges to the practical applications of existing theoretical and experimental findings as well as to potential manipulations of graphene in metamaterials and nanodevices. Toward this end, classical molecular dynamics (MD) simulations are performed with synergetic theoretical analysis to explore the tearing and peeling of self-folded graphene from a substrate driven by external force and by thermal activation. It is found that the elastic energy localized at the small folding ridge plays a significant role in the crack trajectory. Due to the extremely small bending modulus of monolayer graphene, its taper angle when pulled by an external force follows a scaling law distinct from that in case of bilayer graphene. With the increase in the initial width of the folding ridge, the self-folded graphene, motivated by thermal fluctuations, can be self-assembled by spontaneous self-tearing and peeling from a substrate. Simultaneously, the scaling law between the taper angle and adhesive energy is independent of the motivations for thermal activation-induced self-assembly and external force tearing, providing effective insights into the underlying physics for graphene-based origami-like folding and kirigami-like cutting.

Organization of Mitochondrial Gene Expression in Two Distinct Ribosome-Containing Assemblies

Directory of Open Access Journals (Sweden)

Kirsten Kehrein

2015-02-01

Full Text Available Mitochondria contain their own genetic system that provides subunits of the complexes driving oxidative phosphorylation. A quarter of the mitochondrial proteome participates in gene expression, but how all these factors are orchestrated and spatially organized is currently unknown. Here, we established a method to purify and analyze native and intact complexes of mitochondrial ribosomes. Quantitative mass spectrometry revealed extensive interactions of ribosomes with factors involved in all the steps of posttranscriptional gene expression. These interactions result in large expressosome-like assemblies that we termed mitochondrial organization of gene expression (MIOREX complexes. Superresolution microscopy revealed that most MIOREX complexes are evenly distributed throughout the mitochondrial network, whereas a subset is present as nucleoid-MIOREX complexes that unite the whole spectrum of organellar gene expression. Our work therefore provides a conceptual framework for the spatial organization of mitochondrial protein synthesis that likely developed to facilitate gene expression in the organelle.

Cyclooxygenase-2 expression and clinical parameters in laryngeal squamous cell carcinoma, vocal fold nodule, and laryngeal atypical hyperplasia.

Science.gov (United States)

Sayar, Cağdaş; Sayar, Hamide; Özdemir, Süleyman; Selçuk, Tahsin; Görgülü, Orhan; Akbaş, Yücel; Kemal Olgun, Mustafa

2013-01-01

The diagnostic role of cyclooxygenase-2 (COX-2) expression in laryngeal atypical hyperplasia, vocal fold nodule, and laryngeal squamous cell carcinoma was examined. Specimens obtained from patients diagnosed with vocal fold nodule (n = 35), atypical hyperplasia (n = 35), laryngeal squamous cell carcinoma (n = 35), and clinical parameters were evaluated retrospectively. Although no staining was observed in patients with vocal fold nodules, staining was noted in laryngeal atypical hyperplasia and squamous cell carcinoma. The percentage of COX-2 staining was the highest in the carcinoma group. It was determined that COX-2 staining was significantly associated with laryngeal squamous cell carcinoma. It should be noted that overexpression of COX-2, a potentially important factor in the evolution of carcinogenesis in precancerous lesions, might be an indicator of the development of carcinoma. Copyright © 2012 Wiley Periodicals, Inc.

Sex Hormone Receptor Expression in the Human Vocal Fold Subunits.

Science.gov (United States)

Kirgezen, Tolga; Sunter, Ahmet Volkan; Yigit, Ozgur; Huq, Gulben Erdem

2017-07-01

The study aimed to evaluate the existence of sex hormone receptors in the subunits of vocal fold. This is a cadaver study. The androgen, estrogen, and progesterone receptors were examined in the epithelium (EP), superficial layer of the lamina propria (SLP), vocal ligament (VL), and macula flava (MF) of the vocal folds from 42 human cadavers (21 male, 21 female) by immunohistochemical methods. Their staining ratios were scored and statistically compared. The androgen receptor score was significantly higher for the MF than for the EP and SLP (P vocal fold, mostly in the MF and VLs. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Simple method for assembly of CRISPR synergistic activation mediator gRNA expression array.

Science.gov (United States)

Vad-Nielsen, Johan; Nielsen, Anders Lade; Luo, Yonglun

2018-05-20

When studying complex interconnected regulatory networks, effective methods for simultaneously manipulating multiple genes expression are paramount. Previously, we have developed a simple method for generation of an all-in-one CRISPR gRNA expression array. We here present a Golden Gate Assembly-based system of synergistic activation mediator (SAM) compatible CRISPR/dCas9 gRNA expression array for the simultaneous activation of multiple genes. Using this system, we demonstrated the simultaneous activation of the transcription factors, TWIST, SNAIL, SLUG, and ZEB1 a human breast cancer cell line. Copyright © 2018 Elsevier B.V. All rights reserved.

Self-folding micropatterned polymeric containers.

Science.gov (United States)

Azam, Anum; Laflin, Kate E; Jamal, Mustapha; Fernandes, Rohan; Gracias, David H

2011-02-01

We demonstrate self-folding of precisely patterned, optically transparent, all-polymeric containers and describe their utility in mammalian cell and microorganism encapsulation and culture. The polyhedral containers, with SU-8 faces and biodegradable polycaprolactone (PCL) hinges, spontaneously assembled on heating. Self-folding was driven by a minimization of surface area of the liquefying PCL hinges within lithographically patterned two-dimensional (2D) templates. The strategy allowed for the fabrication of containers with variable polyhedral shapes, sizes and precisely defined porosities in all three dimensions. We provide proof-of-concept for the use of these polymeric containers as encapsulants for beads, chemicals, mammalian cells and bacteria. We also compare accelerated hinge degradation rates in alkaline solutions of varying pH. These optically transparent containers resemble three-dimensional (3D) micro-Petri dishes and can be utilized to sustain, monitor and deliver living biological components.

Natural triple beta-stranded fibrous folds.

Science.gov (United States)

Mitraki, Anna; Papanikolopoulou, Katerina; Van Raaij, Mark J

2006-01-01

A distinctive family of beta-structured folds has recently been described for fibrous proteins from viruses. Virus fibers are usually involved in specific host-cell recognition. They are asymmetric homotrimeric proteins consisting of an N-terminal virus-binding tail, a central shaft or stalk domain, and a C-terminal globular receptor-binding domain. Often they are entirely or nearly entirely composed of beta-structure. Apart from their biological relevance and possible gene therapy applications, their shape, stability, and rigidity suggest they may be useful as blueprints for biomechanical design. Folding and unfolding studies suggest their globular C-terminal domain may fold first, followed by a "zipping-up" of the shaft domains. The C-terminal domains appear to be important for registration because peptides corresponding to shaft domains alone aggregate into nonnative fibers and/or amyloid structures. C-terminal domains can be exchanged between different fibers and the resulting chimeric proteins are useful as a way to solve structures of unknown parts of the shaft domains. The following natural triple beta-stranded fibrous folds have been discovered by X-ray crystallography: the triple beta-spiral, triple beta-helix, and T4 short tail fiber fold. All have a central longitudinal hydrophobic core and extensive intermonomer polar and nonpolar interactions. Now that a reasonable body of structural and folding knowledge has been assembled about these fibrous proteins, the next challenge and opportunity is to start using this information in medical and industrial applications such as gene therapy and nanotechnology.

Cation-induced folding of alginate-bearing bilayer gels: an unusual example of spontaneous folding along the long axis.

Science.gov (United States)

Athas, Jasmin C; Nguyen, Catherine P; Kummar, Shailaa; Raghavan, Srinivasa R

2018-04-04

The spontaneous folding of flat gel films into tubes is an interesting example of self-assembly. Typically, a rectangular film folds along its short axis when forming a tube; folding along the long axis has been seen only in rare instances when the film is constrained. Here, we report a case where the same free-swelling gel film folds along either its long or short axis depending on the concentration of a solute. Our gels are sandwiches (bilayers) of two layers: a passive layer of cross-linked N,N'-dimethylyacrylamide (DMAA) and an active layer of cross-linked DMAA that also contains chains of the biopolymer alginate. Multivalent cations like Ca2+ and Cu2+ induce these bilayer gels to fold into tubes. The folding occurs instantly when a flat film of the gel is introduced into a solution of these cations. The likely cause for folding is that the active layer stiffens and shrinks (because the alginate chains in it get cross-linked by the cations) whereas the passive layer is unaffected. The resulting mismatch in swelling degree between the two layers creates internal stresses that drive folding. Cations that are incapable of cross-linking alginate, such as Na+ and Mg2+, do not induce gel folding. Moreover, the striking aspect is the direction of folding. When the Ca2+ concentration is high (100 mM or higher), the gels fold along their long axis, whereas when the Ca2+ concentration is low (40 to 80 mM), the gels fold along their short axis. We hypothesize that the folding axis is dictated by the inhomogeneous nature of alginate-cation cross-linking, i.e., that the edges get cross-linked before the faces of the gel. At high Ca2+ concentration, the stiffer edges constrain the folding; in turn, the gel folds such that the longer edges are deformed less, which explains the folding along the long axis. At low Ca2+ concentration, the edges and the faces of the gel are more similar in their degree of cross-linking; therefore, the gel folds along its short axis. An analogy

Optimization of expression and purification of human mortalin (Hsp70): Folding/unfolding analysis

Science.gov (United States)

Khan, Mohd Shahnawaz; Ahmed, Anwar; Tabrez, Shams; Islam, Badar ul; Rabbani, Nayyar; Malik, Ajamaluddin; Ismael, Mohamad A.; Alsenaidy, Mohammad A.; Alsenaidy, Abdulrahman M.

2017-12-01

Human mortalin is a Hsp70 mitochondrial protein that plays an essential role in the biogenesis of mitochondria. The deregulation of mortalin expression and its functions could lead to several age-associated disorders and some types of cancers. In the present study, we optimized the expression and purification of recombinant human mortalin by the use of two-step chromatography. Low temperature (18 °C) and 0.5 mM (IPTG) was required for optimum mortalin expression. Chaperone activity of mortalin was assessed by the citrate synthase and insulin protection assay, which suggested their protective role in mitochondria. Folding and unfolding assessments of mortalin were carried out in the presence of guanidine hydrochloride (GdnHCl) by intrinsic fluorescence measurement, ANS (8-analino 1-nephthlene sulfonic acid) binding and CD (circular dichroism) analysis. Under denaturing conditions, mortalin showed decrease in tryptophan fluorescence intensity along with a red shift of 11 nm. Moreover, ANS binding studies illustrated decrease in hydrophobicity. CD measurement of mortalin showed a predominant helical structure. However, the secondary structure was lost at low concentration of GdnHCl (1 M). We present a simple and robust method to produce soluble mortalin and warranted that chaperones are also susceptible to unfolding and futile to maintain protein homeostasis.

In vitro assembly of Ebola virus nucleocapsid-like complex expressed in E. coli

Directory of Open Access Journals (Sweden)

Ruchao Peng

2016-09-01

Full Text Available Abstract Ebola virus (EBOV harbors an RNA genome encapsidated by nucleoprotein (NP along with other viral proteins to form a nucleocapsid complex. Previous Cryo-eletron tomography and biochemical studies have shown the helical structure of EBOV nucleocapsid at nanometer resolution and the first 450 amino-acid of NP (NPΔ451–739 alone is capable of forming a helical nucleocapsid-like complex (NLC. However, the structural basis for NP-NP interaction and the dynamic procedure of the nucleocapsid assembly is yet poorly understood. In this work, we, by using an E. coli expression system, captured a series of images of NPΔ451–739 conformers at different stages of NLC assembly by negative-stain electron microscopy, which allowed us to picture the dynamic procedure of EBOV nucleocapsid assembly. Along with further biochemical studies, we showed the assembly of NLC is salt-sensitive, and also established an indispensible role of RNA in this process. We propose the diverse modes of NLC elongation might be the key determinants shaping the plasticity of EBOV virions. Our findings provide a new model for characterizing the self-oligomerization of viral nucleoproteins and studying the dynamic assembly process of viral nucleocapsid in vitro.

Structural basis of the 9-fold symmetry of centrioles.

Science.gov (United States)

Kitagawa, Daiju; Vakonakis, Ioannis; Olieric, Natacha; Hilbert, Manuel; Keller, Debora; Olieric, Vincent; Bortfeld, Miriam; Erat, Michèle C; Flückiger, Isabelle; Gönczy, Pierre; Steinmetz, Michel O

2011-02-04

The centriole, and the related basal body, is an ancient organelle characterized by a universal 9-fold radial symmetry and is critical for generating cilia, flagella, and centrosomes. The mechanisms directing centriole formation are incompletely understood and represent a fundamental open question in biology. Here, we demonstrate that the centriolar protein SAS-6 forms rod-shaped homodimers that interact through their N-terminal domains to form oligomers. We establish that such oligomerization is essential for centriole formation in C. elegans and human cells. We further generate a structural model of the related protein Bld12p from C. reinhardtii, in which nine homodimers assemble into a ring from which nine coiled-coil rods radiate outward. Moreover, we demonstrate that recombinant Bld12p self-assembles into structures akin to the central hub of the cartwheel, which serves as a scaffold for centriole formation. Overall, our findings establish a structural basis for the universal 9-fold symmetry of centrioles. Copyright © 2011 Elsevier Inc. All rights reserved.

Sequence assembly

DEFF Research Database (Denmark)

Scheibye-Alsing, Karsten; Hoffmann, S.; Frankel, Annett Maria

2009-01-01

Despite the rapidly increasing number of sequenced and re-sequenced genomes, many issues regarding the computational assembly of large-scale sequencing data have remain unresolved. Computational assembly is crucial in large genome projects as well for the evolving high-throughput technologies and...... in genomic DNA, highly expressed genes and alternative transcripts in EST sequences. We summarize existing comparisons of different assemblers and provide a detailed descriptions and directions for download of assembly programs at: http://genome.ku.dk/resources/assembly/methods.html....

Protein folding simulations: from coarse-grained model to all-atom model.

Science.gov (United States)

Zhang, Jian; Li, Wenfei; Wang, Jun; Qin, Meng; Wu, Lei; Yan, Zhiqiang; Xu, Weixin; Zuo, Guanghong; Wang, Wei

2009-06-01

Protein folding is an important and challenging problem in molecular biology. During the last two decades, molecular dynamics (MD) simulation has proved to be a paramount tool and was widely used to study protein structures, folding kinetics and thermodynamics, and structure-stability-function relationship. It was also used to help engineering and designing new proteins, and to answer even more general questions such as the minimal number of amino acid or the evolution principle of protein families. Nowadays, the MD simulation is still undergoing rapid developments. The first trend is to toward developing new coarse-grained models and studying larger and more complex molecular systems such as protein-protein complex and their assembling process, amyloid related aggregations, and structure and motion of chaperons, motors, channels and virus capsides; the second trend is toward building high resolution models and explore more detailed and accurate pictures of protein folding and the associated processes, such as the coordination bond or disulfide bond involved folding, the polarization, charge transfer and protonate/deprotonate process involved in metal coupled folding, and the ion permeation and its coupling with the kinetics of channels. On these new territories, MD simulations have given many promising results and will continue to offer exciting views. Here, we review several new subjects investigated by using MD simulations as well as the corresponding developments of appropriate protein models. These include but are not limited to the attempt to go beyond the topology based Gō-like model and characterize the energetic factors in protein structures and dynamics, the study of the thermodynamics and kinetics of disulfide bond involved protein folding, the modeling of the interactions between chaperonin and the encapsulated protein and the protein folding under this circumstance, the effort to clarify the important yet still elusive folding mechanism of protein BBL

Effects of two mutations detected in medium chain acyl-CoA dehydrogenase (MCAD)-deficient patients on folding, oligomer assembly, and stability of MCAD enzyme

DEFF Research Database (Denmark)

Bross, P; Jespersen, C; Jensen, T G

1995-01-01

We have used expression of human medium chain acyl-CoA dehydrogenase (MCAD) in Escherichia coli as a model system for dissecting the molecular effects of two mutations detected in patients with MCAD deficiency. We demonstrate that the R28C mutation predominantly affects polypeptide folding...

Insights into the role of elastin in vocal fold health and disease

Science.gov (United States)

Moore, Jaime

2011-01-01

Elastic fibers are large, complex and surprisingly poorly understood extracellular matrix (ECM) macromolecules. The elastin fiber, generated from a single human gene - elastin (ELN), is a self assembling integral protein that endows critical mechanic proprieties to elastic tissues and organs such as the skin, lungs, and arteries. The biology of elastic fibers is complex because they have multiple components, a tightly regulated developmental deposition, a multi-step hierarchical assembly and unique biomechanical functions. Elastin is present in vocal folds, where it plays a pivotal role in the quality of phonation. This review article provides an overview of the genesis of elastin and its wide- ranging structure and function. Specific distribution within the vocal fold lamina propria across the lifespan in normal and pathological states and its contribution to vocal fold biomechanics will be examined. Elastin and elastin-derived molecules are increasingly investigated for their application in tissue engineering. The properties of various elastin– based materials will be discussed and their current and future applications evaluated. A new level of understanding of the biomechanical properties of vocal fold elastin composites and their molecular basis should lead to new strategies for elastic fiber repair and regeneration in aging and disease. PMID:21708449

PREFACE Protein folding: lessons learned and new frontiers Protein folding: lessons learned and new frontiers

Science.gov (United States)

Pappu, Rohit V.; Nussinov, Ruth

2009-03-01

multi-scale dynamical problem when one considers the synergies between protein expression, spontaneous folding, chaperonin-assisted folding, protein targeting, the kinetics of post-translational modifications, protein degradation, and of course the drive to avoid aggregation. Further, there is growing recognition that cells not only tolerate but select for proteins that are intrinsically disordered. These proteins are essential for many crucial activities, and yet their inability to fold in isolation makes them prone to proteolytic processing and aggregation. In the series of papers that make up this special focus on protein folding in physical biology, leading researchers provide insights into diverse cross-sections of problems in protein folding. Barrick provides a concise review of what we have learned from the study of two-state folders and draws attention to how several unanswered questions are being approached using studies on large repeat proteins. Dissecting the contribution of hydration-mediated interactions to driving forces for protein folding and assembly has been extremely challenging. There is renewed interest in using hydrostatic pressure as a tool to access folding intermediates and decipher the role of partially hydrated states in folding, misfolding, and aggregation. Silva and Foguel review many of the nuances that have been uncovered by perturbing hydrostatic pressure as a thermodynamic parameter. As noted above, protein folding in vivo is expected to be considerably more complex than the folding of two-state proteins in dilute solutions. Lucent et al review the state-of-the-art in the development of quantitative theories to explain chaperonin-assisted folding in vivo. Additionally, they highlight unanswered questions pertaining to the processing of unfolded/misfolded proteins by the chaperone machinery. Zhuang et al present results that focus on the effects of surface tethering on transition state ensembles and folding mechanisms of a model two

Functional chiral hydrogen-bonded assemblies

NARCIS (Netherlands)

Mateos timoneda, Miguel

2005-01-01

In this thesis different aspects of functional hydrogen-bonded (double and tetrarosette) assemblies are described. The functions were inspired by naturally occurring mechanisms such as molecular recognition, supramolecular chirality and its origin, and biostrategies for the correct folding of

Assembly and misassembly of cystic fibrosis transmembrane conductance regulator: folding defects caused by deletion of F508 occur before and after the calnexin-dependent association of membrane spanning domain (MSD) 1 and MSD2.

Science.gov (United States)

Rosser, Meredith F N; Grove, Diane E; Chen, Liling; Cyr, Douglas M

2008-11-01

Cystic fibrosis transmembrane conductance regulator (CFTR) is a polytopic membrane protein that functions as a Cl(-) channel and consists of two membrane spanning domains (MSDs), two cytosolic nucleotide binding domains (NBDs), and a cytosolic regulatory domain. Cytosolic 70-kDa heat shock protein (Hsp70), and endoplasmic reticulum-localized calnexin are chaperones that facilitate CFTR biogenesis. Hsp70 functions in both the cotranslational folding and posttranslational degradation of CFTR. Yet, the mechanism for calnexin action in folding and quality control of CFTR is not clear. Investigation of this question revealed that calnexin is not essential for CFTR or CFTRDeltaF508 degradation. We identified a dependence on calnexin for proper assembly of CFTR's membrane spanning domains. Interestingly, efficient folding of NBD2 was also found to be dependent upon calnexin binding to CFTR. Furthermore, we identified folding defects caused by deletion of F508 that occurred before and after the calnexin-dependent association of MSD1 and MSD2. Early folding defects are evident upon translation of the NBD1 and R-domain and are sensed by the RMA-1 ubiquitin ligase complex.

High-resolution structure of a retroviral protease folded as a monomer

International Nuclear Information System (INIS)

Gilski, Miroslaw; Kazmierczyk, Maciej; Krzywda, Szymon; Zábranská, Helena; Cooper, Seth; Popović, Zoran; Khatib, Firas; DiMaio, Frank; Thompson, James; Baker, David; Pichová, Iva; Jaskolski, Mariusz

2011-01-01

The crystal structure of Mason–Pfizer monkey virus protease folded as a monomer has been solved by molecular replacement using a model generated by players of the online game Foldit. The structure shows at high resolution the details of a retroviral protease folded as a monomer which can guide rational design of protease dimerization inhibitors as retroviral drugs. Mason–Pfizer monkey virus (M-PMV), a D-type retrovirus assembling in the cytoplasm, causes simian acquired immunodeficiency syndrome (SAIDS) in rhesus monkeys. Its pepsin-like aspartic protease (retropepsin) is an integral part of the expressed retroviral polyproteins. As in all retroviral life cycles, release and dimerization of the protease (PR) is strictly required for polyprotein processing and virion maturation. Biophysical and NMR studies have indicated that in the absence of substrates or inhibitors M-PMV PR should fold into a stable monomer, but the crystal structure of this protein could not be solved by molecular replacement despite countless attempts. Ultimately, a solution was obtained in mr-rosetta using a model constructed by players of the online protein-folding game Foldit. The structure indeed shows a monomeric protein, with the N- and C-termini completely disordered. On the other hand, the flap loop, which normally gates access to the active site of homodimeric retropepsins, is clearly traceable in the electron density. The flap has an unusual curled shape and a different orientation from both the open and closed states known from dimeric retropepsins. The overall fold of the protein follows the retropepsin canon, but the C α deviations are large and the active-site ‘DTG’ loop (here NTG) deviates up to 2.7 Å from the standard conformation. This structure of a monomeric retropepsin determined at high resolution (1.6 Å) provides important extra information for the design of dimerization inhibitors that might be developed as drugs for the treatment of retroviral infections

Chinese mitten crab (Eriocheir sinensis) iron-sulphur cluster assembly protein 2 (EsIscA2) is differentially regulated after immune and oxidative stress challenges.

Science.gov (United States)

Zhang, Peng; Liu, Yu; Wang, Min; Dong, Miren; Liu, Zhaoqun; Jia, Zhihao; Wang, Weilin; Zhang, Anguo; Wang, Lingling; Song, Linsheng

2018-07-01

Iron-sulphur clusters (ISCs), one of the oldest and most versatile cofactors of proteins, are involved in catalysis reactions, electron transport reactions, regulation processes as well as sensing of ambient conditions. Iron-sulphur cluster assembly protein (IscA) is a scaffold protein member of ISC formation system, which plays a significant role in the assembly and maturation process of ISC proteins. In the present study, the cDNA sequence of iron-sulphur cluster assembly protein 2 (designated as EsIscA2) was cloned from Eriocheir sinensis. The open reading frame (ORF) of EsIscA2 was of 507 bp, encoding a peptide of 168 amino acids with a typically conserved Fe-S domain. A tetrameric form was predicated by the SWISS-MODEL prediction algorithm, and three conserved cysteine residues (Cys-93, Cys-158, Cys-160) from each IscA monomer were predicted to form a 'cysteine pocket'. The deduced amino acid sequence of EsIscA2 shared over 50% similarity with that of other IscAs. EsIscA2 was clustered with IscA2 proteins from invertebrates and vertebrates, indicating that the protein was highly conservative in the evolution. rEsIscA2 exhibited a high iron binding affinity in the concentration ranging from 2 to 200 μM. EsIscA2 transcripts were detected in all the tested tissues including gonad, hemocytes, gill, muscle, heart, hepatopancreas and eyestalk, and EsIscA2 protein was detected in the mitochondria of hemocytes. The highest mRNA expression level of EsIscA2 was detected in muscle and hepatopancreas, which was about 34.66-fold (p < 0.05) and 27.07-fold (p < 0.05) of that in hemocytes, respectively. After Aeromonas hydrophila and lipopolysaccharide (LPS) stimulations, the mRNA expression of EsIscA2 in hemocytes was down-regulated and reached the lowest level at 24 h (0.31-fold, p < 0.05) and 48 h (0.29-fold, p < 0.05) compared to control group, respectively. And the expression of EsIscA2 mRNA in hepatopancreas was repressed from 6 h to 48 h post

A Versatile System for USER Cloning-Based Assembly of Expression Vectors for Mammalian Cell Engineering

DEFF Research Database (Denmark)

Lund, Anne Mathilde; Kildegaard, Helene Faustrup; Petersen, Maja Borup Kjær

2014-01-01

, in addition the system is fully extendable by other users. The vector system is designed to facilitate high-throughput genome-scale studies of mammalian cells, such as the newly sequenced CHO cell lines, through the ability to rapidly generate high-fidelity assembly of customizable gene expression vectors....

Dramatic improvement in genome assembly achieved using doubled-haploid genomes.

Science.gov (United States)

Zhang, Hong; Tan, Engkong; Suzuki, Yutaka; Hirose, Yusuke; Kinoshita, Shigeharu; Okano, Hideyuki; Kudoh, Jun; Shimizu, Atsushi; Saito, Kazuyoshi; Watabe, Shugo; Asakawa, Shuichi

2014-10-27

Improvement in de novo assembly of large genomes is still to be desired. Here, we improved draft genome sequence quality by employing doubled-haploid individuals. We sequenced wildtype and doubled-haploid Takifugu rubripes genomes, under the same conditions, using the Illumina platform and assembled contigs with SOAPdenovo2. We observed 5.4-fold and 2.6-fold improvement in the sizes of the N50 contig and scaffold of doubled-haploid individuals, respectively, compared to the wildtype, indicating that the use of a doubled-haploid genome aids in accurate genome analysis.

Isothermal folding of a light-up bio-orthogonal RNA origami nanoribbon.

Science.gov (United States)

Torelli, Emanuela; Kozyra, Jerzy Wieslaw; Gu, Jing-Ying; Stimming, Ulrich; Piantanida, Luca; Voïtchovsky, Kislon; Krasnogor, Natalio

2018-05-03

RNA presents intringuing roles in many cellular processes and its versatility underpins many different applications in synthetic biology. Nonetheless, RNA origami as a method for nanofabrication is not yet fully explored and the majority of RNA nanostructures are based on natural pre-folded RNA. Here we describe a biologically inert and uniquely addressable RNA origami scaffold that self-assembles into a nanoribbon by seven staple strands. An algorithm is applied to generate a synthetic De Bruijn scaffold sequence that is characterized by the lack of biologically active sites and repetitions larger than a predetermined design parameter. This RNA scaffold and the complementary staples fold in a physiologically compatible isothermal condition. In order to monitor the folding, we designed a new split Broccoli aptamer system. The aptamer is divided into two nonfunctional sequences each of which is integrated into the 5' or 3' end of two staple strands complementary to the RNA scaffold. Using fluorescence measurements and in-gel imaging, we demonstrate that once RNA origami assembly occurs, the split aptamer sequences are brought into close proximity forming the aptamer and turning on the fluorescence. This light-up 'bio-orthogonal' RNA origami provides a prototype that can have potential for in vivo origami applications.

Vocal Fold Vibratory Changes Following Surgical Intervention.

Science.gov (United States)

Chen, Wenli; Woo, Peak; Murry, Thomas

2016-03-01

High-speed videoendoscopy (HSV) captures direct cycle-to-cycle visualization of vocal fold movement in real time. This ultrafast recording rate is capable of visualizing the vibratory motion of the vocal folds in severely disordered phonation and provides a direct method for examining vibratory changes after vocal fold surgery. The purpose of this study was to examine the vibratory motion before and after surgical intervention. HSV was captured from two subjects with identifiable midvocal fold benign lesions and six subjects with highly aperiodic vocal fold vibration before and after phonosurgery. Digital kymography (DKG) was used to extract high-speed kymographic vocal fold images sampled at the midmembranous, anterior 1/3, and posterior 1/3 region. Spectral analysis was subsequently applied to the DKG to quantify the cycle-to-cycle movements of the left and the right vocal fold, expressed as a spectrum. Before intervention, the vibratory spectrum consisted of decreased and flat-like spectral peaks with robust power asymmetry. After intervention, increases in spectral power and decreases in power symmetry were noted. Spectral power increases were most remarkable in the midmembranous region of the vocal fold. Surgical modification resulted in improved lateral excursion of the vocal folds, vibratory function, and perceptual measures of Voice Handicap Index-10. These changes in vibratory behavior trended toward normal vocal fold vibration. Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

NR4A1 is an endogenous inhibitor of vocal fold fibrosis.

Science.gov (United States)

Hiwatashi, Nao; Bing, Renjie; Kraja, Iv; Branski, Ryan C

2017-09-01

NR4A1 was recently identified as an endogenous inhibitor of transforming growth factor (TGF)-β-induced fibrosis, and the role of this nuclear receptor has not been elucidated in tissue health or the response to injury in the vocal folds. Given the clinical implications of vocal fold fibrosis, we investigated NR4A1 expression during vocal fold wound healing in vivo and the regulatory roles of NR4A1 on vocal fold fibroblasts (VFFs) in vitro with the ultimate goal of developing targeted therapies for this challenging patient population. In vivo and in vitro. In vivo, the temporal pattern of NR4A1 mRNA expression was quantified following rat vocal fold injury. In vitro, the role of NR4A1 on TGF-β1-mediated transcription of genes underlying fibrosis as well as myofibroblast differentiation and collagen gel contraction was quantified in our human VFF line. Small interfering RNA was employed to alter NR4A1 expression to further elucidate this complex system. Nr4a1 mRNA increased 1 day after injury and peaked at 7 days. Knockdown of NR4A1 resulted in upregulation of COL1A1 and TGF-β1, with TGF-β1 stimulation (both P vocal fold health or disease. Upregulation of TGF-β following vocal fold injury was concurrent with increased NR4A1 expression. These data provide a foundation for the development of therapeutic strategies given persistent TGF-β signaling in vocal fold fibrosis. N/A Laryngoscope, 127:E317-E323, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Method of generating ploynucleotides encoding enhanced folding variants

Energy Technology Data Exchange (ETDEWEB)

Bradbury, Andrew M.; Kiss, Csaba; Waldo, Geoffrey S.

2017-05-02

The invention provides directed evolution methods for improving the folding, solubility and stability (including thermostability) characteristics of polypeptides. In one aspect, the invention provides a method for generating folding and stability-enhanced variants of proteins, including but not limited to fluorescent proteins, chromophoric proteins and enzymes. In another aspect, the invention provides methods for generating thermostable variants of a target protein or polypeptide via an internal destabilization baiting strategy. Internally destabilization a protein of interest is achieved by inserting a heterologous, folding-destabilizing sequence (folding interference domain) within DNA encoding the protein of interest, evolving the protein sequences adjacent to the heterologous insertion to overcome the destabilization (using any number of mutagenesis methods), thereby creating a library of variants. The variants in the library are expressed, and those with enhanced folding characteristics selected.

Two- and three-dimensional folding of thin film single-crystalline silicon for photovoltaic power applications.

Science.gov (United States)

Guo, Xiaoying; Li, Huan; Ahn, Bok Yeop; Duoss, Eric B; Hsia, K Jimmy; Lewis, Jennifer A; Nuzzo, Ralph G

2009-12-01

Fabrication of 3D electronic structures in the micrometer-to-millimeter range is extremely challenging due to the inherently 2D nature of most conventional wafer-based fabrication methods. Self-assembly, and the related method of self-folding of planar patterned membranes, provide a promising means to solve this problem. Here, we investigate self-assembly processes driven by wetting interactions to shape the contour of a functional, nonplanar photovoltaic (PV) device. A mechanics model based on the theory of thin plates is developed to identify the critical conditions for self-folding of different 2D geometrical shapes. This strategy is demonstrated for specifically designed millimeter-scale silicon objects, which are self-assembled into spherical, and other 3D shapes and integrated into fully functional light-trapping PV devices. The resulting 3D devices offer a promising way to efficiently harvest solar energy in thin cells using concentrator microarrays that function without active light tracking systems.

Muscular anatomy of the human ventricular folds.

Science.gov (United States)

Moon, Jerald; Alipour, Fariborz

2013-09-01

Our purpose in this study was to better understand the muscular anatomy of the ventricular folds in order to help improve biomechanical modeling of phonation and to better understand the role of these muscles during phonatory and nonphonatory tasks. Four human larynges were decalcified, sectioned coronally from posterior to anterior by a CryoJane tape transfer system, and stained with Masson's trichrome. The total and relative areas of muscles observed in each section were calculated and used for characterizing the muscle distribution within the ventricular folds. The ventricular folds contained anteriorly coursing thyroarytenoid and ventricularis muscle fibers that were in the lower half of the ventricular fold posteriorly, and some ventricularis muscle was evident in the upper and lateral portions of the fold more anteriorly. Very little muscle tissue was observed in the medial half of the fold, and the anterior half of the ventricular fold was largely devoid of any muscle tissue. All 4 larynges contained muscle bundles that coursed superiorly and medially through the upper half of the fold, toward the lateral margin of the epiglottis. Although variability of expression was evident, a well-defined thyroarytenoid muscle was readily apparent lateral to the arytenoid cartilage in all specimens.

Modeling programmable deformation of self-folding all-polymer structures with temperature-sensitive hydrogels

International Nuclear Information System (INIS)

Guo, Wei; Zhou, Jinxiong; Li, Meie

2013-01-01

Combination of soft active hydrogels with hard passive polymers gives rise to all-polymer composites. The hydrogel is sensitive to external stimuli while the passive polymer is inert. Utilizing the different behaviors of two materials subject to environmental variation, for example temperature, results in self-folding soft machines. We report our efforts to model the programmable deformation of self-folding structures with temperature-sensitive hydrogels. The self-folding structures are realized either by constructing a bilayer structure or by incorporating hydrogels as hinges. The methodology and the results may aid the design, control and fabrication of 3D complex structures from 2D simple configurations through self-assembly. (paper)

The soluble loop BC region guides, but not dictates, the assembly of the transmembrane cytochrome b6.

Directory of Open Access Journals (Sweden)

Lydia Tome-Stangl

Full Text Available Studying folding and assembly of naturally occurring α-helical transmembrane proteins can inspire the design of membrane proteins with defined functions. Thus far, most studies have focused on the role of membrane-integrated protein regions. However, to fully understand folding pathways and stabilization of α-helical membrane proteins, it is vital to also include the role of soluble loops. We have analyzed the impact of interhelical loops on folding, assembly and stability of the heme-containing four-helix bundle transmembrane protein cytochrome b6 that is involved in charge transfer across biomembranes. Cytochrome b6 consists of two transmembrane helical hairpins that sandwich two heme molecules. Our analyses strongly suggest that the loop connecting the helical hairpins is not crucial for positioning the two protein "halves" for proper folding and assembly of the holo-protein. Furthermore, proteolytic removal of any of the remaining two loops, which connect the two transmembrane helices of a hairpin structure, appears to also not crucially effect folding and assembly. Overall, the transmembrane four-helix bundle appears to be mainly stabilized via interhelical interactions in the transmembrane regions, while the soluble loop regions guide assembly and stabilize the holo-protein. The results of this study might steer future strategies aiming at designing heme-binding four-helix bundle structures, involved in transmembrane charge transfer reactions.

Assembly and characterization of foot-and-mouth disease virus empty capsid particles expressed within mammalian cells

DEFF Research Database (Denmark)

Gullberg, Maria; Muszynski, Bartosz; Organtini, Lindsey J.

2013-01-01

The foot-and-mouth disease virus (FMDV) structural protein precursor, P1-2A, is cleaved by the virus-encoded 3C protease (3Cpro) into the capsid proteins VP0, VP1 and VP3 (and 2A). In some systems, it is difficult to produce large amounts of these processed capsid proteins since 3Cpro can be toxic...... (from serotypes O and A) and 3Cpro were expressed from monocistronic cDNA cassettes as P1-2A-3C, or from dicistronic cassettes with the 3Cpro expression dependent on a mutant FMDV internal ribosome entry site (IRES) (designated P1-2A-mIRES-3C). The effects of using a mutant 3Cpro with reduced catalytic....... These products self-assembled to form FMDV empty capsid particles, which have a related, but distinct, morphology (as determined by electron microscopy and reconstruction) from that determined previously by X-ray crystallography. The assembled empty capsids bind, in a divalent cation-dependent manner, to the RGD...

Keratinocytes express fibrillin and assemble microfibrils: implications for dermal matrix organization.

Science.gov (United States)

Haynes, S L; Shuttleworth, C A; Kielty, C M

1997-07-01

Fibrillin-containing microfibrils are key architectural structures of the upper dermis and integral components of the dermal elastic fibre network. Microfibril bundles intercalate into the dermal-epithelial junction and provide an elastic connection between the dermal elastic fibre network and the epidermis. Immunohistochemical studies have suggested that they are laid down both at the dermal-epithelial junction and in the deep dermis. While dermal fibroblasts are responsible for deposition of the elastin and microfibrillar components that comprise the elastic fibres of the deep dermis, the cellular origin of the microfibril bundles that extrude from the dermal-epithelial junction is not well defined. We have used fresh tissues, freshly isolated epidermis and primary human and porcine keratinocyte cultures to investigate the possibility that keratinocytes are responsible for deposition of these microfibrils. We have shown that keratinocytes in vivo and in vitro synthesize both fibrillin-1 and fibrillin-2, and assemble beaded microfibrils concurrently with expression of basement membrane collagen. These observations suggest that keratinocytes co-ordinate the secretion, deposition and assembly of these distinct structural elements of the dermal matrix, and have important implications for skin remodelling.

Model-directed engineering of "difficult-to-express" monoclonal antibody production by Chinese hamster ovary cells.

Science.gov (United States)

Pybus, Leon P; Dean, Greg; West, Nathan R; Smith, Andrew; Daramola, Olalekan; Field, Ray; Wilkinson, Stephen J; James, David C

2014-02-01

Despite improvements in volumetric titer for monoclonal antibody (MAb) production processes using Chinese hamster ovary (CHO) cells, some "difficult-to-express" (DTE) MAbs inexplicably reach much lower process titers. These DTE MAbs require intensive cell line and process development activity, rendering them more costly or even unsuitable to manufacture. To rapidly and rationally identify an optimal strategy to improve production of DTE MAbs, we have developed an engineering design platform combining high-yielding transient production, empirical modeling of MAb synthesis incorporating an unfolded protein response (UPR) regulatory loop with directed expression and cell engineering approaches. Utilizing a panel of eight IgG1 λ MAbs varying >4-fold in volumetric titer, we showed that MAb-specific limitations on folding and assembly rate functioned to induce a proportionate UPR in host CHO cells with a corresponding reduction in cell growth rate. Derived from comparative empirical modeling of cellular constraints on the production of each MAb we employed two strategies to increase production of DTE MAbs designed to avoid UPR induction through an improvement in the rate/cellular capacity for MAb folding and assembly reactions. Firstly, we altered the transfected LC:HC gene ratio and secondly, we co-expressed a variety of molecular chaperones, foldases or UPR transactivators (BiP, CypB, PDI, and active forms of ATF6 and XBP1) with recombinant MAbs. DTE MAb production was significantly improved by both strategies, although the mode of action was dependent upon the approach employed. Increased LC:HC ratio or CypB co-expression improved cell growth with no effect on qP. In contrast, BiP, ATF6c and XBP1s co-expression increased qP and reduced cell growth. This study demonstrates that expression-engineering strategies to improve production of DTE proteins in mammalian cells should be product specific, and based on rapid predictive tools to assess the relative impact of

Digital gene expression analysis based on integrated de novo transcriptome assembly of sweet potato [Ipomoea batatas (L. Lam].

Directory of Open Access Journals (Sweden)

Xiang Tao

Full Text Available BACKGROUND: Sweet potato (Ipomoea batatas L. [Lam.] ranks among the top six most important food crops in the world. It is widely grown throughout the world with high and stable yield, strong adaptability, rich nutrient content, and multiple uses. However, little is known about the molecular biology of this important non-model organism due to lack of genomic resources. Hence, studies based on high-throughput sequencing technologies are needed to get a comprehensive and integrated genomic resource and better understanding of gene expression patterns in different tissues and at various developmental stages. METHODOLOGY/PRINCIPAL FINDINGS: Illumina paired-end (PE RNA-Sequencing was performed, and generated 48.7 million of 75 bp PE reads. These reads were de novo assembled into 128,052 transcripts (≥ 100 bp, which correspond to 41.1 million base pairs, by using a combined assembly strategy. Transcripts were annotated by Blast2GO and 51,763 transcripts got BLASTX hits, in which 39,677 transcripts have GO terms and 14,117 have ECs that are associated with 147 KEGG pathways. Furthermore, transcriptome differences of seven tissues were analyzed by using Illumina digital gene expression (DGE tag profiling and numerous differentially and specifically expressed transcripts were identified. Moreover, the expression characteristics of genes involved in viral genomes, starch metabolism and potential stress tolerance and insect resistance were also identified. CONCLUSIONS/SIGNIFICANCE: The combined de novo transcriptome assembly strategy can be applied to other organisms whose reference genomes are not available. The data provided here represent the most comprehensive and integrated genomic resources for cloning and identifying genes of interest in sweet potato. Characterization of sweet potato transcriptome provides an effective tool for better understanding the molecular mechanisms of cellular processes including development of leaves and storage roots

Comparative study the expression of calcium cycling genes in Bombay duck (Harpadon nehereus and beltfish (Trichiurus lepturus with different swimming activities

Directory of Open Access Journals (Sweden)

Hui Zhang

2017-06-01

Full Text Available The contraction and relaxation events of the muscle is mediated by the coordination of many important calcium cycling proteins of ryanodine receptor (RYR, troponin C (TNNC, parvalbumin (PVALB, sarcoendoplasmic reticulum calcium transport ATPase (SERCA and calsequestrin (CASQ. In higher vertebrates, the expression level of calcium cycling proteins are positively correlated to the muscle contraction/relaxation ability of the cell. In this study, we used RNAseq to explore the expression profile of calcium cycling genes between two marine fish of Bombay duck (Harpadon nehereus and beltfish (Trichiurus lepturus with poor and robust swimming activities, respectively. We have studied the hypothesis whether the expression level of calcium cycling proteins are also positive correlated to swimming ability in fish. We used Illumina sequencing technology (NextSeq500 to sequence, assemble and annotate the muscle transcriptome of Bombay duck for the first time. A total of 47,752,240 cleaned reads (deposited in NCBI SRA database with accession number of SRX1706379 were obtained from RNA sequencing and 26,288 unigenes (with N50 of 486 bp were obtained after de novo assembling with Trinity software. BLASTX against NR, GO, KEGG and eggNOG databases show 100%, 65%, 26%, 94% and 88% annotation rate, respectively. Comparison of the dominantly expressed unigenes in fish muscle shows calcium cycling gene expression in beltfish (SRX1674471 is 1.4- to 51.6-fold higher than Bombay duck. Among five calcium cycling genes, the fold change results are very significant in CASQ (51.6 fold and PVALB (9.1 fold and both of them are responsive for calcium binding to reduce free calcium concentration in the sarcoendoplasmic reticulum and cytoplasm. In conclusion, we confirmed that the high abundant expression rate of calcium cycling genes in robust swimming fish species. The current muscle transcriptome and identified calcium cycling gene data can provide more insights into the

The Complexity of Folding Self-Folding Origami

Science.gov (United States)

Stern, Menachem; Pinson, Matthew B.; Murugan, Arvind

2017-10-01

Why is it difficult to refold a previously folded sheet of paper? We show that even crease patterns with only one designed folding motion inevitably contain an exponential number of "distractor" folding branches accessible from a bifurcation at the flat state. Consequently, refolding a sheet requires finding the ground state in a glassy energy landscape with an exponential number of other attractors of higher energy, much like in models of protein folding (Levinthal's paradox) and other NP-hard satisfiability (SAT) problems. As in these problems, we find that refolding a sheet requires actuation at multiple carefully chosen creases. We show that seeding successful folding in this way can be understood in terms of subpatterns that fold when cut out ("folding islands"). Besides providing guidelines for the placement of active hinges in origami applications, our results point to fundamental limits on the programmability of energy landscapes in sheets.

The Complexity of Folding Self-Folding Origami

Directory of Open Access Journals (Sweden)

Menachem Stern

2017-12-01

Full Text Available Why is it difficult to refold a previously folded sheet of paper? We show that even crease patterns with only one designed folding motion inevitably contain an exponential number of “distractor” folding branches accessible from a bifurcation at the flat state. Consequently, refolding a sheet requires finding the ground state in a glassy energy landscape with an exponential number of other attractors of higher energy, much like in models of protein folding (Levinthal’s paradox and other NP-hard satisfiability (SAT problems. As in these problems, we find that refolding a sheet requires actuation at multiple carefully chosen creases. We show that seeding successful folding in this way can be understood in terms of subpatterns that fold when cut out (“folding islands”. Besides providing guidelines for the placement of active hinges in origami applications, our results point to fundamental limits on the programmability of energy landscapes in sheets.

Structural Aspects of Bacterial Outer Membrane Protein Assembly.

Science.gov (United States)

Calmettes, Charles; Judd, Andrew; Moraes, Trevor F

2015-01-01

The outer membrane of Gram-negative bacteria is predominantly populated by β-Barrel proteins and lipid anchored proteins that serve a variety of biological functions. The proper folding and assembly of these proteins is essential for bacterial viability and often plays a critical role in virulence and pathogenesis. The β-barrel assembly machinery (Bam) complex is responsible for the proper assembly of β-barrels into the outer membrane of Gram-negative bacteria, whereas the localization of lipoproteins (Lol) system is required for proper targeting of lipoproteins to the outer membrane.

Protein-like Nanoparticles Based on Orthogonal Self-Assembly of Chimeric Peptides.

Science.gov (United States)

Jiang, Linhai; Xu, Dawei; Namitz, Kevin E; Cosgrove, Michael S; Lund, Reidar; Dong, He

2016-10-01

A novel two-component self-assembling chimeric peptide is designed where two orthogonal protein folding motifs are linked side by side with precisely defined position relative to one another. The self-assembly is driven by a combination of symmetry controlled molecular packing, intermolecular interactions, and geometric constraint to limit the assembly into compact dodecameric protein nanoparticles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Assembly constraints drive co-evolution among ribosomal constituents.

Science.gov (United States)

Mallik, Saurav; Akashi, Hiroshi; Kundu, Sudip

2015-06-23

Ribosome biogenesis, a central and essential cellular process, occurs through sequential association and mutual co-folding of protein-RNA constituents in a well-defined assembly pathway. Here, we construct a network of co-evolving nucleotide/amino acid residues within the ribosome and demonstrate that assembly constraints are strong predictors of co-evolutionary patterns. Predictors of co-evolution include a wide spectrum of structural reconstitution events, such as cooperativity phenomenon, protein-induced rRNA reconstitutions, molecular packing of different rRNA domains, protein-rRNA recognition, etc. A correlation between folding rate of small globular proteins and their topological features is known. We have introduced an analogous topological characteristic for co-evolutionary network of ribosome, which allows us to differentiate between rRNA regions subjected to rapid reconstitutions from those hindered by kinetic traps. Furthermore, co-evolutionary patterns provide a biological basis for deleterious mutation sites and further allow prediction of potential antibiotic targeting sites. Understanding assembly pathways of multicomponent macromolecules remains a key challenge in biophysics. Our study provides a 'proof of concept' that directly relates co-evolution to biophysical interactions during multicomponent assembly and suggests predictive power to identify candidates for critical functional interactions as well as for assembly-blocking antibiotic target sites. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

An Intramolecular Chaperone Inserted in Bacteriophage P22 Coat Protein Mediates Its Chaperonin-independent Folding*

Science.gov (United States)

Suhanovsky, Margaret M.; Teschke, Carolyn M.

2013-01-01

The bacteriophage P22 coat protein has the common HK97-like fold but with a genetically inserted domain (I-domain). The role of the I-domain, positioned at the outermost surface of the capsid, is unknown. We hypothesize that the I-domain may act as an intramolecular chaperone because the coat protein folds independently, and many folding mutants are localized to the I-domain. The function of the I-domain was investigated by generating the coat protein core without its I-domain and the isolated I-domain. The core coat protein shows a pronounced folding defect. The isolated I-domain folds autonomously and has a high thermodynamic stability and fast folding kinetics in the presence of a peptidyl prolyl isomerase. Thus, the I-domain provides thermodynamic stability to the full-length coat protein so that it can fold reasonably efficiently while still allowing the HK97-like core to retain the flexibility required for conformational switching during procapsid assembly and maturation. PMID:24126914

De novo transcriptome assembly, functional annotation and differential gene expression analysis of juvenile and adult E. fetida, a model oligochaete used in ecotoxicological studies

Directory of Open Access Journals (Sweden)

Michelle Thunders

Full Text Available Abstract Background Earthworms are sensitive to toxic chemicals present in the soil and so are useful indicator organisms for soil health. Eisenia fetida are commonly used in ecotoxicological studies; therefore the assembly of a baseline transcriptome is important for subsequent analyses exploring the impact of toxin exposure on genome wide gene expression. Results This paper reports on the de novo transcriptome assembly of E. fetida using Trinity, a freely available software tool. Trinotate was used to carry out functional annotation of the Trinity generated transcriptome file and the transdecoder generated peptide sequence file along with BLASTX, BLASTP and HMMER searches and were loaded into a Sqlite3 database. To identify differentially expressed transcripts; each of the original sequence files were aligned to the de novo assembled transcriptome using Bowtie and then RSEM was used to estimate expression values based on the alignment. EdgeR was used to calculate differential expression between the two conditions, with an FDR corrected P value cut off of 0.001, this returned six significantly differentially expressed genes. Initial BLASTX hits of these putative genes included hits with annelid ferritin and lysozyme proteins, as well as fungal NADH cytochrome b5 reductase and senescence associated proteins. At a cut off of P = 0.01 there were a further 26 differentially expressed genes. Conclusion These data have been made publicly available, and to our knowledge represent the most comprehensive available transcriptome for E. fetida assembled from RNA sequencing data. This provides important groundwork for subsequent ecotoxicogenomic studies exploring the impact of the environment on global gene expression in E. fetida and other earthworm species.

Two- and three-dimensional folding of thin film single-crystalline silicon for photovoltaic power applications

OpenAIRE

Guo, Xiaoying; Li, Huan; Yeop Ahn, Bok; Duoss, Eric B.; Hsia, K. Jimmy; Lewis, Jennifer A.; Nuzzo, Ralph G.

2009-01-01

Fabrication of 3D electronic structures in the micrometer-to-millimeter range is extremely challenging due to the inherently 2D nature of most conventional wafer-based fabrication methods. Self-assembly, and the related method of self-folding of planar patterned membranes, provide a promising means to solve this problem. Here, we investigate self-assembly processes driven by wetting interactions to shape the contour of a functional, nonplanar photovoltaic (PV) device. A mechanics model based ...

Still Heart Encodes a Structural HMT, SMYD1b, with Chaperone-Like Function during Fast Muscle Sarcomere Assembly.

Directory of Open Access Journals (Sweden)

Kendal Prill

Full Text Available The vertebrate sarcomere is a complex and highly organized contractile structure whose assembly and function requires the coordination of hundreds of proteins. Proteins require proper folding and incorporation into the sarcomere by assembly factors, and they must also be maintained and replaced due to the constant physical stress of muscle contraction. Zebrafish mutants affecting muscle assembly and maintenance have proven to be an ideal tool for identification and analysis of factors necessary for these processes. The still heart mutant was identified due to motility defects and a nonfunctional heart. The cognate gene for the mutant was shown to be smyd1b and the still heart mutation results in an early nonsense codon. SMYD1 mutants show a lack of heart looping and chamber definition due to a lack of expression of heart morphogenesis factors gata4, gata5 and hand2. On a cellular level, fast muscle fibers in homozygous mutants do not form mature sarcomeres due to the lack of fast muscle myosin incorporation by SMYD1b when sarcomeres are first being assembled (19hpf, supporting SMYD1b as an assembly protein during sarcomere formation.

Fiscal 1999 achievement report on research and development project on intellectual infrastructure creation and utilization technologies. Development of efficient protein expression system (Development of efficient protein expression system utilizing protein folding mechanism of hyperthermophilic bacteria); 1999 nendo kokoritsu tanpakushitsu hatsugen system no kaihatsu seika hokokusho. Chokonetsukin no tanpakushitsu oritatami kiko wo riyoshita kokoritsu tanpakushitsu hatsugen system no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

Efforts were exerted to achieve efficient expression of proteins of hyperthermophilic bacteria, hyperthermophilic archaeabacteria in particular, using a heterogene expression system in which Escherichia coli was the host. In an effort to search for genes related to protein folding and to elucidate the mechanism of folding, chaperonin and prefoldin subunit genes, out of various factors participating in protein folding in hyperthermophilic archaeabacteria, were cloned, and expressed in Escherichia coli. As a system for analyzing protein folding reaction, an experimental system was established on a substrate comprising isopropyl malate dehydrogenase, citrate synthase, glucose dehydrogenase, and a green fluorescent protein. Studies were further conducted to elucidate the mechanism of expression of enzyme genes in Escherichia coli for the establishment of a mass production method for useful enzymes. Also carried out was the research and development of an element technology evaluation system involving protein expression. (NEDO)

Goose parvovirus structural proteins expressed by recombinant baculoviruses self-assemble into virus-like particles with strong immunogenicity in goose

International Nuclear Information System (INIS)

Ju, Huanyu; Wei, Na; Wang, Qian; Wang, Chunyuan; Jing, Zhiqiang; Guo, Lu; Liu, Dapeng; Gao, Mingchun; Ma, Bo; Wang, Junwei

2011-01-01

Highlights: → All three capsid proteins can be expressed in insect cells in baculovirus expression system. → All three recombinant proteins were spontaneously self-assemble into virus-like particles whose size and appearance were similar to those of native purified GPV virions. → The immunogenicity of GPV-VLPs was better than commercial inactivated vaccine and attenuated vaccine. -- Abstract: Goose parvovirus (GPV), a small non-enveloped ssDNA virus, can cause Derzsy's disease, and three capsid proteins of VP1, VP2, and VP3 are encoded by an overlapping nucleotide sequence. However, little is known on whether recombinant viral proteins (VPs) could spontaneously assemble into virus-like particles (VLPs) in insect cells and whether these VLPs could retain their immunoreactivity and immunogenicity in susceptible geese. To address these issues, genes for these GPV VPs were amplified by PCR, and the recombinant VPs proteins were expressed in insect cells using a baculovirus expression system for the characterization of their structures, immunoreactivity, and immunogenicity. The rVP1, rVP2, and rVP3 expressed in Sf9 cells were detected by anti-GPV sera, anti-VP3 sera, and anti-His antibodies, respectively. Electron microscopy revealed that these rVPs spontaneously assembled into VLPs in insect cells, similar to that of the purified wild-type GPV virions. In addition, vaccination with individual types of VLPs, particularly with the rVP2-VLPs, induced higher titers of antibodies and neutralized different strains of GPVs in primary goose and duck embryo fibroblast cells in vitro. These data indicated that these VLPs retained immunoreactivity and had strong immunogenicity in susceptible geese. Therefore, our findings may provide a framework for development of new vaccines for the prevention of Derzsy's disease and vehicles for the delivery of drugs.

Goose parvovirus structural proteins expressed by recombinant baculoviruses self-assemble into virus-like particles with strong immunogenicity in goose

Energy Technology Data Exchange (ETDEWEB)

Ju, Huanyu; Wei, Na; Wang, Qian; Wang, Chunyuan; Jing, Zhiqiang; Guo, Lu; Liu, Dapeng; Gao, Mingchun; Ma, Bo [College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030 (China); Wang, Junwei, E-mail: jwwang@neau.edu.cn [College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030 (China)

2011-05-27

Highlights: {yields} All three capsid proteins can be expressed in insect cells in baculovirus expression system. {yields} All three recombinant proteins were spontaneously self-assemble into virus-like particles whose size and appearance were similar to those of native purified GPV virions. {yields} The immunogenicity of GPV-VLPs was better than commercial inactivated vaccine and attenuated vaccine. -- Abstract: Goose parvovirus (GPV), a small non-enveloped ssDNA virus, can cause Derzsy's disease, and three capsid proteins of VP1, VP2, and VP3 are encoded by an overlapping nucleotide sequence. However, little is known on whether recombinant viral proteins (VPs) could spontaneously assemble into virus-like particles (VLPs) in insect cells and whether these VLPs could retain their immunoreactivity and immunogenicity in susceptible geese. To address these issues, genes for these GPV VPs were amplified by PCR, and the recombinant VPs proteins were expressed in insect cells using a baculovirus expression system for the characterization of their structures, immunoreactivity, and immunogenicity. The rVP1, rVP2, and rVP3 expressed in Sf9 cells were detected by anti-GPV sera, anti-VP3 sera, and anti-His antibodies, respectively. Electron microscopy revealed that these rVPs spontaneously assembled into VLPs in insect cells, similar to that of the purified wild-type GPV virions. In addition, vaccination with individual types of VLPs, particularly with the rVP2-VLPs, induced higher titers of antibodies and neutralized different strains of GPVs in primary goose and duck embryo fibroblast cells in vitro. These data indicated that these VLPs retained immunoreactivity and had strong immunogenicity in susceptible geese. Therefore, our findings may provide a framework for development of new vaccines for the prevention of Derzsy's disease and vehicles for the delivery of drugs.

Folded plate assemblies with branching column supports : Interaction and control of overall shape

NARCIS (Netherlands)

Falk, A.; Turrin, M.; von Buelow, P.

2010-01-01

The work described in this paper aims at developing the interrelation and overall effects of interaction between a folded plate roof structure and a system of branching column supports. In the context of architectural performance it is of interest to discuss the effects of the material on

The co-chaperones Fkbp4/5 control Argonaute2 expression and facilitate RISC assembly.

Science.gov (United States)

Martinez, Natalia J; Chang, Hao-Ming; Borrajo, Jacob de Riba; Gregory, Richard I

2013-11-01

Argonaute2 (Ago2) protein and associated microRNAs (miRNAs) or small interfering RNAs (siRNAs) form the RNA-induced silencing complex (RISC) for target messenger RNA cleavage and post-transcriptional gene silencing. Although Ago2 is essential for RISC activity, the mechanism of RISC assembly is not well understood, and factors controlling Ago2 protein expression are largely unknown. A role for the Hsc70/Hsp90 chaperone complex in loading small RNA duplexes into the RISC has been demonstrated in cell extracts, and unloaded Ago2 is unstable and degraded by the lysosome in mammalian cells. Here we identify the co-chaperones Fkbp4 and Fkbp5 as Ago2-associated proteins in mouse embryonic stem cells. Pharmacological inhibition of this interaction using FK506 or siRNA-mediated Fkbp4/5 depletion leads to decreased Ago2 protein levels. We find FK506 treatment inhibits, whereas Fkbp4/5 overexpression promotes, miRNA-mediated stabilization of Ago2 expression. Simultaneous treatment with a lysosome inhibitor revealed the accumulation of unloaded Ago2 complexes in FK506-treated cells. We find that, consistent with unloaded miRNAs being unstable, FK506 treatment also affects miRNA abundance, particularly nascent miRNAs. Our results support a role for Fkbp4/5 in RISC assembly.

Adipose-derived mesenchymal stromal cells prevented rat vocal fold scarring.

Science.gov (United States)

Morisaki, Tsuyoshi; Kishimoto, Yo; Tateya, Ichiro; Kawai, Yoshitaka; Suzuki, Ryo; Tsuji, Takuya; Hiwatashi, Nao; Nakamura, Tatsuo; Omori, Koichi; Kitano, Hiroya; Takeuchi, Hiromi; Hirano, Shigeru

2018-01-01

This study aimed to reveal the effects of adipose-derived mesenchymal stromal cells (ASCs) on prevention of vocal fold scarring by investigating how the immediate ASCs transplantation into the injured rat vocal fold affect the levels of gene transcription and translation. Prospective animal experiments with controls. ASCs harvested from green fluorescent protein transgenic rat (ASCs group) or saline (sham group) were injected into the thyroarytenoid muscle of Sprague-Dawley rats immediately after stripping the vocal fold. For histological examinations, larynges were extirpated at 3, 14, and 56 days after the injection. Quantitative real-time polymerase chain reaction (PCR) analyses were performed at 3 and 14 days after the injection. Transplanted ASCs were detected only in larynges at day 3. At days 14 and 56, histological examination showed significantly higher amounts of hyaluronic acid and lower deposition of collagen in the ASCs group compared to the sham group. Real-time PCR revealed that the ASCs group showed low expression of procollagen (Col)1a1, Col1a3, matrix metalloproteinase (Mmp)1 and Mmp8 in each time points. The ASCs group showed high expression of fibroblast growth factor (Fgf)2 and Hepatocyte growth factor (Hgf) compared to the sham group at day 14. ASCs increased expressions of Fgf2 and Hgf, and suppressed excessive collagen deposition during vocal fold wound healing. Given the fact that ASCs survived no more than 14 days, ASCs were thought to induce upregulations of growth factors' genes in surrounding cells. These results suggested that ASCs have potential to prevent vocal fold scarring. NA. Laryngoscope, 128:E33-E40, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Cholera toxin B subunits assemble into pentamers--proposition of a fly-casting mechanism.

Directory of Open Access Journals (Sweden)

Jihad Zrimi

Full Text Available The cholera toxin B pentamer (CtxB(5, which belongs to the AB(5 toxin family, is used as a model study for protein assembly. The effect of the pH on the reassembly of the toxin was investigated using immunochemical, electrophoretic and spectroscopic methods. Three pH-dependent steps were identified during the toxin reassembly: (i acquisition of a fully assembly-competent fold by the CtxB monomer, (ii association of CtxB monomer into oligomers, (iii acquisition of the native fold by the CtxB pentamer. The results show that CtxB(5 and the related heat labile enterotoxin LTB(5 have distinct mechanisms of assembly despite sharing high sequence identity (84% and almost identical atomic structures. The difference can be pinpointed to four histidines which are spread along the protein sequence and may act together. Thus, most of the toxin B amino acids appear negligible for the assembly, raising the possibility that assembly is driven by a small network of amino acids instead of involving all of them.

SHuffle, a novel Escherichia coli protein expression strain capable of correctly folding disulfide bonded proteins in its cytoplasm

Directory of Open Access Journals (Sweden)

Lobstein Julie

2012-05-01

Full Text Available Abstract Background Production of correctly disulfide bonded proteins to high yields remains a challenge. Recombinant protein expression in Escherichia coli is the popular choice, especially within the research community. While there is an ever growing demand for new expression strains, few strains are dedicated to post-translational modifications, such as disulfide bond formation. Thus, new protein expression strains must be engineered and the parameters involved in producing disulfide bonded proteins must be understood. Results We have engineered a new E. coli protein expression strain named SHuffle, dedicated to producing correctly disulfide bonded active proteins to high yields within its cytoplasm. This strain is based on the trxB gor suppressor strain SMG96 where its cytoplasmic reductive pathways have been diminished, allowing for the formation of disulfide bonds in the cytoplasm. We have further engineered a major improvement by integrating into its chromosome a signal sequenceless disulfide bond isomerase, DsbC. We probed the redox state of DsbC in the oxidizing cytoplasm and evaluated its role in assisting the formation of correctly folded multi-disulfide bonded proteins. We optimized protein expression conditions, varying temperature, induction conditions, strain background and the co-expression of various helper proteins. We found that temperature has the biggest impact on improving yields and that the E. coli B strain background of this strain was superior to the K12 version. We also discovered that auto-expression of substrate target proteins using this strain resulted in higher yields of active pure protein. Finally, we found that co-expression of mutant thioredoxins and PDI homologs improved yields of various substrate proteins. Conclusions This work is the first extensive characterization of the trxB gor suppressor strain. The results presented should help researchers design the appropriate protein expression conditions using

Developmental co-expression of small molecular weight apolipoprotein B synthesis and triacylglycerol secretion

International Nuclear Information System (INIS)

Coleman, R.A.; Haynes, E.B.; Sand, T.M.; Davis, R.A.

1987-01-01

The development of the liver's ability to coordinately express the synthesis and secretion of the two major components of very low density lipoproteins (VLDL): triacylglycerol (TG) and apolipoprotein B (apo B) was examined in cultured hepatocytes obtained from fetal, suckling and adult rats. Hepatocytes from fetal and suckling rats synthesized and secreted TG at rates lower than that displayed by adult cells. When TG synthesis was equalized by adding oleic acid to the culture medium, fetal cells still secreted only 39% as much TG as did adult cells. To determine the basis for the apparent defect in VLDL assembly/secretion displayed by fetal cells, the synthesis and secretion of [ 35 S]methionine-labeled apo B was quantified by immunoprecipitation. Although adult and fetal cells synthesized and secreted large molecular weight apo B at similar rates, the synthesis and secretion of small molecular weight apo B was 2-fold greater in adult cells. These data suggest that the ability to assemble/secrete VLDL triacylglycerol varies in parallel with the developmental expression of small molecular weight apo B. Furthermore, these studies show the usefulness of the cultured rat hepatocyte model for examining the ontogeny and regulation of VLDL assembly/secretion

Double folded Yukawa interaction potential between two heavy ions

International Nuclear Information System (INIS)

Bulgac, A.; Carstoiu, F.; Dumitrescu, O.

1980-02-01

A simple semi-analytical formula for the heavy ion interaction potential within the double-folding model approximation is obtained. The folded interaction is assumed to be expressed in Yukawa terms or the derivatives of them. The densities used can be both experimental or theoretical (of simple ''step-wise'', ''Fermi-Saxon-Woods'' or complicated ''shell model'' structure) densities. A way of inserting the exchange terms is discussed. Numerical calculations for some colliding partners are reported. (author)

Self-assembled DNA Structures for Nanoconstruction

Science.gov (United States)

Yan, Hao; Yin, Peng; Park, Sung Ha; Li, Hanying; Feng, Liping; Guan, Xiaoju; Liu, Dage; Reif, John H.; LaBean, Thomas H.

2004-09-01

In recent years, a number of research groups have begun developing nanofabrication methods based on DNA self-assembly. Here we review our recent experimental progress to utilize novel DNA nanostructures for self-assembly as well as for templates in the fabrication of functional nano-patterned materials. We have prototyped a new DNA nanostructure known as a cross structure. This nanostructure has a 4-fold symmetry which promotes its self-assembly into tetragonal 2D lattices. We have utilized the tetragonal 2D lattices as templates for highly conductive metallic nanowires and periodic 2D protein nano-arrays. We have constructed and characterized a DNA nanotube, a new self-assembling superstructure composed of DNA tiles. We have also demonstrated an aperiodic DNA lattice composed of DNA tiles assembled around a long scaffold strand; the system translates information encoded in the scaffold strand into a specific and reprogrammable barcode pattern. We have achieved metallic nanoparticle linear arrays templated on self-assembled 1D DNA arrays. We have designed and demonstrated a 2-state DNA lattice, which displays expand/contract motion switched by DNA nanoactuators. We have also achieved an autonomous DNA motor executing unidirectional motion along a linear DNA track.

PAVE: Program for assembling and viewing ESTs

Directory of Open Access Journals (Sweden)

Bomhoff Matthew

2009-08-01

Full Text Available Abstract Background New sequencing technologies are rapidly emerging. Many laboratories are simultaneously working with the traditional Sanger ESTs and experimenting with ESTs generated by the 454 Life Science sequencers. Though Sanger ESTs have been used to generate contigs for many years, no program takes full advantage of the 5' and 3' mate-pair information, hence, many tentative transcripts are assembled into two separate contigs. The new 454 technology has the benefit of high-throughput expression profiling, but introduces time and space problems for assembling large contigs. Results The PAVE (Program for Assembling and Viewing ESTs assembler takes advantage of the 5' and 3' mate-pair information by requiring that the mate-pairs be assembled into the same contig and joined by n's if the two sub-contigs do not overlap. It handles the depth of 454 data sets by "burying" similar ESTs during assembly, which retains the expression level information while circumventing time and space problems. PAVE uses MegaBLAST for the clustering step and CAP3 for assembly, however it assembles incrementally to enforce the mate-pair constraint, bury ESTs, and reduce incorrect joins and splits. The PAVE data management system uses a MySQL database to store multiple libraries of ESTs along with their metadata; the management system allows multiple assemblies with variations on libraries and parameters. Analysis routines provide standard annotation for the contigs including a measure of differentially expressed genes across the libraries. A Java viewer program is provided for display and analysis of the results. Our results clearly show the benefit of using the PAVE assembler to explicitly use mate-pair information and bury ESTs for large contigs. Conclusion The PAVE assembler provides a software package for assembling Sanger and/or 454 ESTs. The assembly software, data management software, Java viewer and user's guide are freely available.

PAVE: program for assembling and viewing ESTs.

Science.gov (United States)

Soderlund, Carol; Johnson, Eric; Bomhoff, Matthew; Descour, Anne

2009-08-26

New sequencing technologies are rapidly emerging. Many laboratories are simultaneously working with the traditional Sanger ESTs and experimenting with ESTs generated by the 454 Life Science sequencers. Though Sanger ESTs have been used to generate contigs for many years, no program takes full advantage of the 5' and 3' mate-pair information, hence, many tentative transcripts are assembled into two separate contigs. The new 454 technology has the benefit of high-throughput expression profiling, but introduces time and space problems for assembling large contigs. The PAVE (Program for Assembling and Viewing ESTs) assembler takes advantage of the 5' and 3' mate-pair information by requiring that the mate-pairs be assembled into the same contig and joined by n's if the two sub-contigs do not overlap. It handles the depth of 454 data sets by "burying" similar ESTs during assembly, which retains the expression level information while circumventing time and space problems. PAVE uses MegaBLAST for the clustering step and CAP3 for assembly, however it assembles incrementally to enforce the mate-pair constraint, bury ESTs, and reduce incorrect joins and splits. The PAVE data management system uses a MySQL database to store multiple libraries of ESTs along with their metadata; the management system allows multiple assemblies with variations on libraries and parameters. Analysis routines provide standard annotation for the contigs including a measure of differentially expressed genes across the libraries. A Java viewer program is provided for display and analysis of the results. Our results clearly show the benefit of using the PAVE assembler to explicitly use mate-pair information and bury ESTs for large contigs. The PAVE assembler provides a software package for assembling Sanger and/or 454 ESTs. The assembly software, data management software, Java viewer and user's guide are freely available.

Interferences of Silica Nanoparticles in Green Fluorescent Protein Folding Processes.

Science.gov (United States)

Klein, Géraldine; Devineau, Stéphanie; Aude, Jean Christophe; Boulard, Yves; Pasquier, Hélène; Labarre, Jean; Pin, Serge; Renault, Jean Philippe

2016-01-12

We investigated the relationship between unfolded proteins, silica nanoparticles and chaperonin to determine whether unfolded proteins could stick to silica surfaces and how this process could impair heat shock protein activity. The HSP60 catalyzed green fluorescent protein (GFP) folding was used as a model system. The adsorption isotherms and adsorption kinetics of denatured GFP were measured, showing that denaturation increases GFP affinity for silica surfaces. This affinity is maintained even if the surfaces are covered by a protein corona and allows silica NPs to interfere directly with GFP folding by trapping it in its unstructured state. We determined also the adsorption isotherms of HSP60 and its chaperonin activity once adsorbed, showing that SiO2 NP can interfere also indirectly with protein folding through chaperonin trapping and inhibition. This inhibition is specifically efficient when NPs are covered first with a layer of unfolded proteins. These results highlight for the first time the antichaperonin activity of silica NPs and ask new questions about the toxicity of such misfolded proteins/nanoparticles assembly toward cells.

Flips for 3-folds and 4-folds

CERN Document Server

Corti, Alessio

2007-01-01

This edited collection of chapters, authored by leading experts, provides a complete and essentially self-contained construction of 3-fold and 4-fold klt flips. A large part of the text is a digest of Shokurov's work in the field and a concise, complete and pedagogical proof of the existence of 3-fold flips is presented. The text includes a ten page glossary and is accessible to students and researchers in algebraic geometry.

Cell origami: self-folding of three-dimensional cell-laden microstructures driven by cell traction force.

Directory of Open Access Journals (Sweden)

Kaori Kuribayashi-Shigetomi

Full Text Available This paper describes a method of generating three-dimensional (3D cell-laden microstructures by applying the principle of origami folding technique and cell traction force (CTF. We harness the CTF as a biological driving force to fold the microstructures. Cells stretch and adhere across multiple microplates. Upon detaching the microplates from a substrate, CTF causes the plates to lift and fold according to a prescribed pattern. This self-folding technique using cells is highly biocompatible and does not involve special material requirements for the microplates and hinges to induce folding. We successfully produced various 3D cell-laden microstructures by just changing the geometry of the patterned 2D plates. We also achieved mass-production of the 3D cell-laden microstructures without causing damage to the cells. We believe that our methods will be useful for biotechnology applications that require analysis of cells in 3D configurations and for self-assembly of cell-based micro-medical devices.

Cell origami: self-folding of three-dimensional cell-laden microstructures driven by cell traction force.

Science.gov (United States)

Kuribayashi-Shigetomi, Kaori; Onoe, Hiroaki; Takeuchi, Shoji

2012-01-01

This paper describes a method of generating three-dimensional (3D) cell-laden microstructures by applying the principle of origami folding technique and cell traction force (CTF). We harness the CTF as a biological driving force to fold the microstructures. Cells stretch and adhere across multiple microplates. Upon detaching the microplates from a substrate, CTF causes the plates to lift and fold according to a prescribed pattern. This self-folding technique using cells is highly biocompatible and does not involve special material requirements for the microplates and hinges to induce folding. We successfully produced various 3D cell-laden microstructures by just changing the geometry of the patterned 2D plates. We also achieved mass-production of the 3D cell-laden microstructures without causing damage to the cells. We believe that our methods will be useful for biotechnology applications that require analysis of cells in 3D configurations and for self-assembly of cell-based micro-medical devices.

Swell Gels to Dumbbell Micelles: Construction of Materials and Nanostructure with Self-assembly

Science.gov (United States)

Pochan, Darrin

2007-03-01

Bionanotechnology, the emerging field of using biomolecular and biotechnological tools for nanostructure or nanotecnology development, provides exceptional opportunity in the design of new materials. Self-assembly of molecules is an attractive materials construction strategy due to its simplicity in application. By considering peptidic or charged synthetic polymer molecules in the bottom-up materials self-assembly design process, one can take advantage of inherently biomolecular attributes; intramolecular folding events, secondary structure, and electrostatic interactions; in addition to more traditional self-assembling molecular attributes such as amphiphilicty, to define hierarchical material structure and consequent properties. Several molecular systems will be discussed. Synthetic block copolymers with charged corona blocks can be assembled in dilute solution containing multivalent organic counterions to produce micelle structures such as toroids. These ring-like micelles are similar to the toroidal bundling of charged semiflexible biopolymers like DNA in the presence of multivalent counterions. Micelle structure can be tuned between toroids, cylinders, and disks simply by using different concentrations or molecular volumes of organic counterion. In addition, these charged blocks can consist of amino acids as monomers producing block copolypeptides. In addition to the above attributes, block copolypeptides provide the control of block secondary structure to further control self-assembly. Design strategies based on small (less than 24 amino acids) beta-hairpin peptides will be discussed. Self-assembly of the peptides is predicated on an intramolecular folding event caused by desired solution properties. Importantly, the intramolecular folding event impart a molecular-level mechanism for environmental responsiveness at the material level (e.g. infinite change in viscosity of a solution to a gel with changes in pH, ionic strength, temperature).

De novo Transcriptome Assembly of Chinese Kale and Global Expression Analysis of Genes Involved in Glucosinolate Metabolism in Multiple Tissues

Science.gov (United States)

Wu, Shuanghua; Lei, Jianjun; Chen, Guoju; Chen, Hancai; Cao, Bihao; Chen, Changming

2017-01-01

Chinese kale, a vegetable of the cruciferous family, is a popular crop in southern China and Southeast Asia due to its high glucosinolate content and nutritional qualities. However, there is little research on the molecular genetics and genes involved in glucosinolate metabolism and its regulation in Chinese kale. In this study, we sequenced and characterized the transcriptomes and expression profiles of genes expressed in 11 tissues of Chinese kale. A total of 216 million 150-bp clean reads were generated using RNA-sequencing technology. From the sequences, 98,180 unigenes were assembled for the whole plant, and 49,582~98,423 unigenes were assembled for each tissue. Blast analysis indicated that a total of 80,688 (82.18%) unigenes exhibited similarity to known proteins. The functional annotation and classification tools used in this study suggested that genes principally expressed in Chinese kale, were mostly involved in fundamental processes, such as cellular and molecular functions, the signal transduction, and biosynthesis of secondary metabolites. The expression levels of all unigenes were analyzed in various tissues of Chinese kale. A large number of candidate genes involved in glucosinolate metabolism and its regulation were identified, and the expression patterns of these genes were analyzed. We found that most of the genes involved in glucosinolate biosynthesis were highly expressed in the root, petiole, and in senescent leaves. The expression patterns of ten glucosinolate biosynthetic genes from RNA-seq were validated by quantitative RT-PCR in different tissues. These results provided an initial and global overview of Chinese kale gene functions and expression activities in different tissues. PMID:28228764

Acute Acrolein Exposure Induces Impairment of Vocal Fold Epithelial Barrier Function.

Directory of Open Access Journals (Sweden)

Xinxin Liu

Full Text Available Acrolein is a ubiquitous pollutant abundant in cigarette smoke, mobile exhaust, and industrial waste. There is limited literature on the effects of acrolein on vocal fold tissue, although there are clinical reports of voice changes after pollutant exposures. Vocal folds are responsible for voice production. The overall objective of this study was to investigate the effects of acrolein exposure on viable, excised vocal fold epithelial tissue and to characterize the mechanism underlying acrolein toxicity. Vocal fold epithelia were studied because they form the outermost layer of the vocal folds and are a primary recipient of inhaled pollutants. Porcine vocal fold epithelia were exposed to 0, 50, 100, 500, 900 or 1300 μM of acrolein for 3 hours; the metabolic activity, epithelial resistance, epithelial permeability, tight junction protein (occludin and claudin 3 expression, cell membrane integrity and lipid peroxidation were investigated. The data demonstrated that acrolein exposure at 500 μM significantly reduced vocal fold epithelial metabolic activity by 27.2% (p≤0.001. Incubation with 100 μM acrolein caused a marked increase in epithelial permeability by 130.5% (p<0.05 and a reduction in transepithelial electrical resistance (TEER by 180.0% (p<0.001. While the expression of tight junctional protein did not change in acrolein-treated samples, the cell membrane integrity was significantly damaged with a 45.6% increase of lipid peroxidation as compared to controls (p<0.05. Taken together, these data provide evidence that acute acrolein exposure impairs vocal fold epithelial barrier integrity. Lipid peroxidation-induced cell membrane damage may play an important role in reducing the barrier function of the epithelium.

A Disulfide Bond-forming Machine Is Linked to the Sortase-mediated Pilus Assembly Pathway in the Gram-positive Bacterium Actinomyces oris*

Science.gov (United States)

Reardon-Robinson, Melissa E.; Osipiuk, Jerzy; Chang, Chungyu; Wu, Chenggang; Jooya, Neda; Joachimiak, Andrzej; Das, Asis; Ton-That, Hung

2015-01-01

Export of cell surface pilins in Gram-positive bacteria likely occurs by the translocation of unfolded precursor polypeptides; however, how the unfolded pilins gain their native conformation is presently unknown. Here, we present physiological studies to demonstrate that the FimA pilin of Actinomyces oris contains two disulfide bonds. Alanine substitution of cysteine residues forming the C-terminal disulfide bridge abrogates pilus assembly, in turn eliminating biofilm formation and polymicrobial interaction. Transposon mutagenesis of A. oris yielded a mutant defective in adherence to Streptococcus oralis, and revealed the essential role of a vitamin K epoxide reductase (VKOR) gene in pilus assembly. Targeted deletion of vkor results in the same defects, which are rescued by ectopic expression of VKOR, but not a mutant containing an alanine substitution in its conserved CXXC motif. Depletion of mdbA, which encodes a membrane-bound thiol-disulfide oxidoreductase, abrogates pilus assembly and alters cell morphology. Remarkably, overexpression of MdbA or a counterpart from Corynebacterium diphtheriae, rescues the Δvkor mutant. By alkylation assays, we demonstrate that VKOR is required for MdbA reoxidation. Furthermore, crystallographic studies reveal that A. oris MdbA harbors a thioredoxin-like fold with the conserved CXXC active site. Consistently, each MdbA enzyme catalyzes proper disulfide bond formation within FimA in vitro that requires the catalytic CXXC motif. Because the majority of signal peptide-containing proteins encoded by A. oris possess multiple Cys residues, we propose that MdbA and VKOR constitute a major folding machine for the secretome of this organism. This oxidative protein folding pathway may be a common feature in Actinobacteria. PMID:26170452

A Disulfide Bond-forming Machine Is Linked to the Sortase-mediated Pilus Assembly Pathway in the Gram-positive Bacterium Actinomyces oris.

Science.gov (United States)

Reardon-Robinson, Melissa E; Osipiuk, Jerzy; Chang, Chungyu; Wu, Chenggang; Jooya, Neda; Joachimiak, Andrzej; Das, Asis; Ton-That, Hung

2015-08-28

Export of cell surface pilins in Gram-positive bacteria likely occurs by the translocation of unfolded precursor polypeptides; however, how the unfolded pilins gain their native conformation is presently unknown. Here, we present physiological studies to demonstrate that the FimA pilin of Actinomyces oris contains two disulfide bonds. Alanine substitution of cysteine residues forming the C-terminal disulfide bridge abrogates pilus assembly, in turn eliminating biofilm formation and polymicrobial interaction. Transposon mutagenesis of A. oris yielded a mutant defective in adherence to Streptococcus oralis, and revealed the essential role of a vitamin K epoxide reductase (VKOR) gene in pilus assembly. Targeted deletion of vkor results in the same defects, which are rescued by ectopic expression of VKOR, but not a mutant containing an alanine substitution in its conserved CXXC motif. Depletion of mdbA, which encodes a membrane-bound thiol-disulfide oxidoreductase, abrogates pilus assembly and alters cell morphology. Remarkably, overexpression of MdbA or a counterpart from Corynebacterium diphtheriae, rescues the Δvkor mutant. By alkylation assays, we demonstrate that VKOR is required for MdbA reoxidation. Furthermore, crystallographic studies reveal that A. oris MdbA harbors a thioredoxin-like fold with the conserved CXXC active site. Consistently, each MdbA enzyme catalyzes proper disulfide bond formation within FimA in vitro that requires the catalytic CXXC motif. Because the majority of signal peptide-containing proteins encoded by A. oris possess multiple Cys residues, we propose that MdbA and VKOR constitute a major folding machine for the secretome of this organism. This oxidative protein folding pathway may be a common feature in Actinobacteria. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Molecular assembly of recombinant chicken type II collagen in the yeast Pichia pastoris.

Science.gov (United States)

Xi, Caixia; Liu, Nan; Liang, Fei; Zhao, Xiao; Long, Juan; Yuan, Fang; Yun, Song; Sun, Yuying; Xi, Yongzhi

2018-01-09

Effective treatment of rheumatoid arthritis can be mediated by native chicken type II collagen (nCCII), recombinant peptide containing nCCII tolerogenic epitopes (CTEs), or a therapeutic DNA vaccine encoding the full-length CCOL2A1 cDNA. As recombinant CCII (rCCII) might avoid potential pathogenic virus contamination during nCCII preparation or chromosomal integration and oncogene activation associated with DNA vaccines, here we evaluated the importance of propeptide and telopeptide domains on rCCII triple helix molecular assembly. We constructed pC- and pN-procollagen (without N- or Cpropeptides, respectively) as well as CTEs located in the triple helical domain lacking both propeptides and telopeptides, and expressed these in yeast Pichia pastoris host strain GS115 (his4, Mut + ) simultaneously with recombinant chicken prolyl-4-hydroxylase α and β subunits. Both pC- and pN-procollagen monomers accumulated inside P. pastoris cells, whereas CTE was assembled into homotrimers with stable conformation and secreted into the supernatants, suggesting that the large molecular weight pC-or pN-procollagens were retained within the endoplasmic reticulum whereas the smaller CTEs proceeded through the secretory pathway. Furthermore, resulting recombinant chicken type II collagen pCα1(II) can induced collagen-induced arthritis (CIA) rat model, which seems to be as effective as the current standard nCCII. Notably, protease digestion assays showed that rCCII could assemble in the absence of C- and N-propeptides or telopeptides. These findings provide new insights into the minimal structural requirements for rCCII expression and folding.

RNA folding: structure prediction, folding kinetics and ion electrostatics.

Science.gov (United States)

Tan, Zhijie; Zhang, Wenbing; Shi, Yazhou; Wang, Fenghua

2015-01-01

Beyond the "traditional" functions such as gene storage, transport and protein synthesis, recent discoveries reveal that RNAs have important "new" biological functions including the RNA silence and gene regulation of riboswitch. Such functions of noncoding RNAs are strongly coupled to the RNA structures and proper structure change, which naturally leads to the RNA folding problem including structure prediction and folding kinetics. Due to the polyanionic nature of RNAs, RNA folding structure, stability and kinetics are strongly coupled to the ion condition of solution. The main focus of this chapter is to review the recent progress in the three major aspects in RNA folding problem: structure prediction, folding kinetics and ion electrostatics. This chapter will introduce both the recent experimental and theoretical progress, while emphasize the theoretical modelling on the three aspects in RNA folding.

Protein solubility and folding enhancement by interaction with RNA.

Directory of Open Access Journals (Sweden)

Seong Il Choi

Full Text Available While basic mechanisms of several major molecular chaperones are well understood, this machinery has been known to be involved in folding of only limited number of proteins inside the cells. Here, we report a chaperone type of protein folding facilitated by interaction with RNA. When an RNA-binding module is placed at the N-terminus of aggregation-prone target proteins, this module, upon binding with RNA, further promotes the solubility of passenger proteins, potentially leading to enhancement of proper protein folding. Studies on in vitro refolding in the presence of RNA, coexpression of RNA molecules in vivo and the mutants with impaired RNA binding ability suggests that RNA can exert chaperoning effect on their bound proteins. The results suggest that RNA binding could affect the overall kinetic network of protein folding pathway in favor of productive folding over off-pathway aggregation. In addition, the RNA binding-mediated solubility enhancement is extremely robust for increasing soluble yield of passenger proteins and could be usefully implemented for high-throughput protein expression for functional and structural genomic research initiatives. The RNA-mediated chaperone type presented here would give new insights into de novo folding in vivo.

Porcine transcriptome analysis based on 97 non-normalized cDNA libraries and assembly of 1,021,891 expressed sequence tags

DEFF Research Database (Denmark)

Gorodkin, Jan; Cirera, Susanna; Hedegaard, Jacob

2007-01-01

public databases. The Sino-Danish ESTs were generated from one normalized and 97 non-normalized cDNA libraries representing 35 different tissues and three developmental stages. RESULTS: Using the Distiller package, the ESTs were assembled to roughly 48,000 contigs and 73,000 singletons, of which...... with the greatest number of different expressed genes, whereas tissues with more specialized function, such as developing liver, have fewer expressed genes. There are at least 65 high confidence housekeeping gene candidates and 876 cDNA library-specific gene candidates. We identified differential expression...

Faucet: streaming de novo assembly graph construction.

Science.gov (United States)

Rozov, Roye; Goldshlager, Gil; Halperin, Eran; Shamir, Ron

2018-01-01

We present Faucet, a two-pass streaming algorithm for assembly graph construction. Faucet builds an assembly graph incrementally as each read is processed. Thus, reads need not be stored locally, as they can be processed while downloading data and then discarded. We demonstrate this functionality by performing streaming graph assembly of publicly available data, and observe that the ratio of disk use to raw data size decreases as coverage is increased. Faucet pairs the de Bruijn graph obtained from the reads with additional meta-data derived from them. We show these metadata-coverage counts collected at junction k-mers and connections bridging between junction pairs-contain most salient information needed for assembly, and demonstrate they enable cleaning of metagenome assembly graphs, greatly improving contiguity while maintaining accuracy. We compared Fauceted resource use and assembly quality to state of the art metagenome assemblers, as well as leading resource-efficient genome assemblers. Faucet used orders of magnitude less time and disk space than the specialized metagenome assemblers MetaSPAdes and Megahit, while also improving on their memory use; this broadly matched performance of other assemblers optimizing resource efficiency-namely, Minia and LightAssembler. However, on metagenomes tested, Faucet,o outputs had 14-110% higher mean NGA50 lengths compared with Minia, and 2- to 11-fold higher mean NGA50 lengths compared with LightAssembler, the only other streaming assembler available. Faucet is available at https://github.com/Shamir-Lab/Faucet. rshamir@tau.ac.il or eranhalperin@gmail.com. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press.

Kinematics, structural mechanics, and design of origami structures with smooth folds

Science.gov (United States)

Peraza Hernandez, Edwin Alexander

Origami provides novel approaches to the fabrication, assembly, and functionality of engineering structures in various fields such as aerospace, robotics, etc. With the increase in complexity of the geometry and materials for origami structures that provide engineering utility, computational models and design methods for such structures have become essential. Currently available models and design methods for origami structures are generally limited to the idealization of the folds as creases of zeroth-order geometric continuity. Such an idealization is not proper for origami structures having non-negligible thickness or maximum curvature at the folds restricted by material limitations. Thus, for general structures, creased folds of merely zeroth-order geometric continuity are not appropriate representations of structural response and a new approach is needed. The first contribution of this dissertation is a model for the kinematics of origami structures having realistic folds of non-zero surface area and exhibiting higher-order geometric continuity, here termed smooth folds. The geometry of the smooth folds and the constraints on their associated kinematic variables are presented. A numerical implementation of the model allowing for kinematic simulation of structures having arbitrary fold patterns is also described. Examples illustrating the capability of the model to capture realistic structural folding response are provided. Subsequently, a method for solving the origami design problem of determining the geometry of a single planar sheet and its pattern of smooth folds that morphs into a given three-dimensional goal shape, discretized as a polygonal mesh, is presented. The design parameterization of the planar sheet and the constraints that allow for a valid pattern of smooth folds and approximation of the goal shape in a known folded configuration are presented. Various testing examples considering goal shapes of diverse geometries are provided. Afterwards, a

Canine parvovirus VP2 protein expressed in silkworm pupae self-assembles into virus-like particles with high immunogenicity.

Directory of Open Access Journals (Sweden)

Hao Feng

Full Text Available The VP2 structural protein of parvovirus can produce virus-like particles (VLPs by a self-assembly process in vitro, making VLPs attractive vaccine candidates. In this study, the VP2 protein of canine parvovirus (CPV was expressed using a baculovirus expression system and assembled into parvovirus-like particles in insect cells and pupae. Electron micrographs of VLPs showed that they were very similar in size and morphology when compared to the wild-type parvovirus. The immunogenicity of the VLPs was investigated in mice and dogs. Mice immunized intramuscularly with purified VLPs, in the absence of an adjuvant, elicited CD4(+ and CD8(+ T cell responses and were able to elicit a neutralizing antibody response against CPV, while the oral administration of raw homogenates containing VLPs to the dogs resulted in a systemic immune response and long-lasting immunity. These results demonstrate that the CPV-VLPs stimulate both cellular and humoral immune responses, and so CPV-VLPs may be a promising candidate vaccine for the prevention of CPV-associated disease.

Canine parvovirus VP2 protein expressed in silkworm pupae self-assembles into virus-like particles with high immunogenicity.

Science.gov (United States)

Feng, Hao; Hu, Gui-qiu; Wang, Hua-lei; Liang, Meng; Liang, Hongru; Guo, He; Zhao, Pingsen; Yang, Yu-jiao; Zheng, Xue-xing; Zhang, Zhi-fang; Zhao, Yong-kun; Gao, Yu-wei; Yang, Song-tao; Xia, Xian-zhu

2014-01-01

The VP2 structural protein of parvovirus can produce virus-like particles (VLPs) by a self-assembly process in vitro, making VLPs attractive vaccine candidates. In this study, the VP2 protein of canine parvovirus (CPV) was expressed using a baculovirus expression system and assembled into parvovirus-like particles in insect cells and pupae. Electron micrographs of VLPs showed that they were very similar in size and morphology when compared to the wild-type parvovirus. The immunogenicity of the VLPs was investigated in mice and dogs. Mice immunized intramuscularly with purified VLPs, in the absence of an adjuvant, elicited CD4(+) and CD8(+) T cell responses and were able to elicit a neutralizing antibody response against CPV, while the oral administration of raw homogenates containing VLPs to the dogs resulted in a systemic immune response and long-lasting immunity. These results demonstrate that the CPV-VLPs stimulate both cellular and humoral immune responses, and so CPV-VLPs may be a promising candidate vaccine for the prevention of CPV-associated disease.

Munc18-1-regulated stage-wise SNARE assembly underlying synaptic exocytosis.

Science.gov (United States)

Ma, Lu; Rebane, Aleksander A; Yang, Guangcan; Xi, Zhiqun; Kang, Yuhao; Gao, Ying; Zhang, Yongli

2015-12-23

Synaptic-soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins couple their stage-wise folding/assembly to rapid exocytosis of neurotransmitters in a Munc18-1-dependent manner. The functions of the different assembly stages in exocytosis and the role of Munc18-1 in SNARE assembly are not well understood. Using optical tweezers, we observed four distinct stages of assembly in SNARE N-terminal, middle, C-terminal, and linker domains (or NTD, MD, CTD, and LD, respectively). We found that SNARE layer mutations differentially affect SNARE assembly. Comparison of their effects on SNARE assembly and on exocytosis reveals that NTD and CTD are responsible for vesicle docking and fusion, respectively, whereas MD regulates SNARE assembly and fusion. Munc18-1 initiates SNARE assembly and structures t-SNARE C-terminus independent of syntaxin N-terminal regulatory domain (NRD) and stabilizes the half-zippered SNARE complex dependent upon the NRD. Our observations demonstrate distinct functions of SNARE domains whose assembly is intimately chaperoned by Munc18-1.

Regeneration of Vocal Fold Mucosa Using Tissue-Engineered Structures with Oral Mucosal Cells

Science.gov (United States)

Fukahori, Mioko; Chitose, Shun-ichi; Sato, Kiminori; Sueyoshi, Shintaro; Kurita, Takashi; Umeno, Hirohito; Monden, Yu; Yamakawa, Ryoji

2016-01-01

Objectives Scarred vocal folds result in irregular vibrations during phonation due to stiffness of the vocal fold mucosa. To date, a completely satisfactory corrective procedure has yet to be achieved. We hypothesize that a potential treatment option for this disease is to replace scarred vocal folds with organotypic mucosa. The purpose of this study is to regenerate vocal fold mucosa using a tissue-engineered structure with autologous oral mucosal cells. Study Design Animal experiment using eight beagles (including three controls). Methods A 3 mm by 3 mm specimen of canine oral mucosa was surgically excised and divided into epithelial and subepithelial tissues. Epithelial cells and fibroblasts were isolated and cultured separately. The proliferated epithelial cells were co-cultured on oriented collagen gels containing the proliferated fibroblasts for an additional two weeks. The organotypic cultured tissues were transplanted to the mucosa-deficient vocal folds. Two months after transplantation, vocal fold vibrations and morphological characteristics were observed. Results A tissue-engineered vocal fold mucosa, consisting of stratified epithelium and lamina propria, was successfully fabricated to closely resemble the normal layered vocal fold mucosa. Laryngeal stroboscopy revealed regular but slightly small mucosal waves at the transplanted site. Immunohistochemically, stratified epithelium expressed cytokeratin, and the distributed cells in the lamina propria expressed vimentin. Elastic Van Gieson staining revealed a decreased number of elastic fibers in the lamina propria of the transplanted site. Conclusion The fabricated mucosa with autologous oral mucosal cells successfully restored the vocal fold mucosa. This reconstruction technique could offer substantial clinical advantages for treating intractable diseases such as scarring of the vocal folds. PMID:26730600

Designing cooperatively folded abiotic uni- and multimolecular helix bundles

Science.gov (United States)

de, Soumen; Chi, Bo; Granier, Thierry; Qi, Ting; Maurizot, Victor; Huc, Ivan

2018-01-01

Abiotic foldamers, that is foldamers that have backbones chemically remote from peptidic and nucleotidic skeletons, may give access to shapes and functions different to those of peptides and nucleotides. However, design methodologies towards abiotic tertiary and quaternary structures are yet to be developed. Here we report rationally designed interactional patterns to guide the folding and assembly of abiotic helix bundles. Computational design facilitated the introduction of hydrogen-bonding functionalities at defined locations on the aromatic amide backbones that promote cooperative folding into helix-turn-helix motifs in organic solvents. The hydrogen-bond-directed aggregation of helices not linked by a turn unit produced several thermodynamically and kinetically stable homochiral dimeric and trimeric bundles with structures that are distinct from the designed helix-turn-helix. Relative helix orientation within the bundles may be changed from parallel to tilted on subtle solvent variations. Altogether, these results prefigure the richness and uniqueness of abiotic tertiary structure behaviour.

Self-assembly of virus-like particles of porcine circovirus type 2 capsid protein expressed from Escherichia coli

Directory of Open Access Journals (Sweden)

Cai Xuepeng

2010-07-01

Full Text Available Abstract Background Porcine circovirus 2 (PCV2 is a serious problem to the swine industry and can lead to significant negative impacts on profitability of pork production. Syndrome associated with PCV2 is known as porcine circovirus closely associated with post-weaning multisystemic wasting syndrome (PMWS. The capsid (Cap protein of PCV2 is a major candidate antigen for development of recombinant vaccine and serological diagnostic method. The recombinant Cap protein has the ability to self-assemble into virus-like particles (VLPs in vitro, it is particularly opportunity to develop the PV2 VLPs vaccine in Escherichia coli,(E.coli , because where the cost of the vaccine must be weighed against the value of the vaccinated pig, when it was to extend use the VLPs vaccine of PCV2. Results In this report, a highly soluble Cap-tag protein expressed in E.coli was constructed with a p-SMK expression vector with a fusion tag of small ubiquitin-like modifiers (SUMO. The recombinant Cap was purified using Ni2+ affinity resins, whereas the tag was used to remove the SUMO protease. Simultaneously, the whole native Cap protein was able to self-assemble into VLPs in vitro when viewed under an electron microscope. The Cap-like particles had a size and shape that resembled the authentic Cap. The result could also be applied in the large-scale production of VLPs of PCV2 and could be used as a diagnostic antigen or a potential VLP vaccine against PCV2 infection in pigs. Conclusion we have, for the first time, utilized the SUMO fusion motif to successfully express the entire authentic Cap protein of PCV2 in E. coli. After the cleavage of the fusion motif, the nCap protein has the ability to self-assemble into VLPs, which can be used as as a potential vaccine to protect pigs from PCV2-infection.

Self-assembly of virus-like particles of porcine circovirus type 2 capsid protein expressed from Escherichia coli

Science.gov (United States)

2010-01-01

Background Porcine circovirus 2 (PCV2) is a serious problem to the swine industry and can lead to significant negative impacts on profitability of pork production. Syndrome associated with PCV2 is known as porcine circovirus closely associated with post-weaning multisystemic wasting syndrome (PMWS). The capsid (Cap) protein of PCV2 is a major candidate antigen for development of recombinant vaccine and serological diagnostic method. The recombinant Cap protein has the ability to self-assemble into virus-like particles (VLPs) in vitro, it is particularly opportunity to develop the PV2 VLPs vaccine in Escherichia coli,(E.coli ), because where the cost of the vaccine must be weighed against the value of the vaccinated pig, when it was to extend use the VLPs vaccine of PCV2. Results In this report, a highly soluble Cap-tag protein expressed in E.coli was constructed with a p-SMK expression vector with a fusion tag of small ubiquitin-like modifiers (SUMO). The recombinant Cap was purified using Ni2+ affinity resins, whereas the tag was used to remove the SUMO protease. Simultaneously, the whole native Cap protein was able to self-assemble into VLPs in vitro when viewed under an electron microscope. The Cap-like particles had a size and shape that resembled the authentic Cap. The result could also be applied in the large-scale production of VLPs of PCV2 and could be used as a diagnostic antigen or a potential VLP vaccine against PCV2 infection in pigs. Conclusion we have, for the first time, utilized the SUMO fusion motif to successfully express the entire authentic Cap protein of PCV2 in E. coli. After the cleavage of the fusion motif, the nCap protein has the ability to self-assemble into VLPs, which can be used as as a potential vaccine to protect pigs from PCV2-infection. PMID:20646322

De Novo Transcriptomes of Forsythia koreana Using a Novel Assembly Method: Insight into Tissue- and Species-Specific Expression of Lignan Biosynthesis-Related Gene.

Directory of Open Access Journals (Sweden)

Akira Shiraishi

Full Text Available Forsythia spp. are perennial woody plants which are one of the most extensively used medicinal sources of Chinese medicines and functional diets owing to their lignan contents. Lignans have received widespread attention as leading compounds in the development of antitumor drugs and healthy diets for reducing the risks of lifestyle-related diseases. However, the molecular basis of Forsythia has yet to be established. In this study, we have verified de novo deep transcriptome of Forsythia koreana leaf and callus using the Illumina HiSeq 1500 platform. A total of 89 million reads were assembled into 116,824 contigs using Trinity, and 1,576 of the contigs displayed the sequence similarity to the enzymes responsible for plant specialized metabolism including lignan biosynthesis. Notably, gene ontology (GO analysis indicated the remarkable enrichment of lignan-biosynthetic enzyme genes in the callus transcriptome. Nevertheless, precise annotation and molecular phylogenetic analyses were hindered by partial sequences of open reading frames (ORFs of the Trinity-based contigs. To obtain more numerous contigs harboring a full-length ORF, we developed a novel overlapping layout consensus-based procedure, virtual primer-based sequence reassembly (VP-seq. VP-seq elucidated 709 full-length ORFs, whereas only 146 full-length ORFs were assembled by Trinity. The comparison of expression profiles of leaf and callus using VP-seq-based full-length ORFs revealed 50-fold upregulation of secoisolariciresinol dehydrogenase (SIRD in callus. Expression and phylogenetic cluster analyses predicted candidates for matairesinol-glucosylating enzymes. We also performed VP-seq analysis of lignan-biosynthetic enzyme genes in the transcriptome data of other lignan-rich plants, Linum flavum, Linum usitatissimum and Podophyllum hexandrum. The comparative analysis indicated both common gene clusters involved in biosynthesis upstream of matairesinol such as SIRD and plant lineage

There and back again: Two views on the protein folding puzzle.

Science.gov (United States)

Finkelstein, Alexei V; Badretdin, Azat J; Galzitskaya, Oxana V; Ivankov, Dmitry N; Bogatyreva, Natalya S; Garbuzynskiy, Sergiy O

2017-07-01

The ability of protein chains to spontaneously form their spatial structures is a long-standing puzzle in molecular biology. Experimentally measured folding times of single-domain globular proteins range from microseconds to hours: the difference (10-11 orders of magnitude) is the same as that between the life span of a mosquito and the age of the universe. This review describes physical theories of rates of overcoming the free-energy barrier separating the natively folded (N) and unfolded (U) states of protein chains in both directions: "U-to-N" and "N-to-U". In the theory of protein folding rates a special role is played by the point of thermodynamic (and kinetic) equilibrium between the native and unfolded state of the chain; here, the theory obtains the simplest form. Paradoxically, a theoretical estimate of the folding time is easier to get from consideration of protein unfolding (the "N-to-U" transition) rather than folding, because it is easier to outline a good unfolding pathway of any structure than a good folding pathway that leads to the stable fold, which is yet unknown to the folding protein chain. And since the rates of direct and reverse reactions are equal at the equilibrium point (as follows from the physical "detailed balance" principle), the estimated folding time can be derived from the estimated unfolding time. Theoretical analysis of the "N-to-U" transition outlines the range of protein folding rates in a good agreement with experiment. Theoretical analysis of folding (the "U-to-N" transition), performed at the level of formation and assembly of protein secondary structures, outlines the upper limit of protein folding times (i.e., of the time of search for the most stable fold). Both theories come to essentially the same results; this is not a surprise, because they describe overcoming one and the same free-energy barrier, although the way to the top of this barrier from the side of the unfolded state is very different from the way from the

Covering folded shapes

Directory of Open Access Journals (Sweden)

Oswin Aichholzer

2014-05-01

Full Text Available Can folding a piece of paper flat make it larger? We explore whether a shape S must be scaled to cover a flat-folded copy of itself. We consider both single folds and arbitrary folds (continuous piecewise isometries \\(S\\to\\mathbb{R}^2\\. The underlying problem is motivated by computational origami, and is related to other covering and fixturing problems, such as Lebesgue's universal cover problem and force closure grasps. In addition to considering special shapes (squares, equilateral triangles, polygons and disks, we give upper and lower bounds on scale factors for single folds of convex objects and arbitrary folds of simply connected objects.

Vocal Fold Vibration Following Surgical Intervention in Three Vocal Pathologies: A Preliminary Study.

Science.gov (United States)

Chen, Wenli; Woo, Peak; Murry, Thomas

2017-09-01

High-speed videoendoscopy captures the cycle-to-cycle vibratory motion of each individual vocal fold in normal and severely disordered phonation. Therefore, it provides a direct method to examine the specific vibratory changes following vocal fold surgery. The purpose of this study was to examine the vocal fold vibratory pattern changes in the surgically treated pathologic vocal fold and the contralateral vocal fold in three vocal pathologies: vocal polyp (n = 3), paresis or paralysis (n = 3), and scar (n = 3). Digital kymography was used to extract high-speed kymographic vocal fold images at the mid-membranous region of the vocal fold. Spectral analysis was subsequently applied to the digital kymography to quantify the cycle-to-cycle movements of each vocal fold, expressed as a spectrum. Surgical modification resulted in significantly improved spectral power of the treated pathologic vocal fold. Furthermore, the contralateral vocal fold also presented with improved spectral power irrespective of vocal pathology. In comparison with normal vocal fold spectrum, postsurgical vocal fold vibrations continued to demonstrate decreased vibratory amplitude in both vocal folds. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Peptide-oligonucleotide conjugates as nanoscale building blocks for assembly of an artificial three-helix protein mimic

DEFF Research Database (Denmark)

Lou, Chenguang; Martos-Maldonado, Manuel C.; Madsen, Charlotte Stahl

2016-01-01

Peptide-based structures can be designed to yield artificial proteins with specific folding patterns and functions. Template-based assembly of peptide units is one design option, but the use of two orthogonal self-assembly principles, oligonucleotide triple helix and a coiled coil protein domain ...

The mathematics of virus shell assembly. Progress report 1995--1996

Energy Technology Data Exchange (ETDEWEB)

Berger, B.

1996-08-01

This research focuses on applying computational and mathematical techniques to problems in biology, and more specifically to problems in protein folding. Significant progress has been made in the following areas relating to virus shell assembly: the local rules theory has been further developed; development has begun on a second-generation simulator which provides a more physically realistic model of assembly, collaborative efforts have continued with an experimental biologist to verify and inspire the local rules theory; an investigation has been initiated into the mechanics of virus shell assembly; laboratory experiments have been conducted on bacteriophage T4 which verify that the previously believed structure for the core may be incorrect.

Photodynamic therapy induces antifibrotic alterations in primary human vocal fold fibroblasts.

Science.gov (United States)

Zhang, Chi; Wang, Jiajia; Chou, Adriana; Gong, Ting; Devine, Erin E; Jiang, Jack J

2018-04-18

Photodynamic therapy (PDT) is a promising treatment modality for laryngeal dysplasia, early-stage carcinoma, and papilloma, and was reported to have the ability to preserve laryngeal function and voice quality without clinical fibrotic response. We aimed to investigate the mechanism behind the antifibrotic effects of PDT on primary human vocal fold fibroblasts (VFFs) in vitro. In vitro analysis from one human donor. Cell viability of VFFs in response to varying doses of PDT was investigated by the Cell Counting Kit-8 method. Sublethal-dose PDT (SL-PDT) was used for the following experiments. Expression of genes related to vocal fold extracellular matrix formation was analyzed by real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blotting. Effects of PDT on cell migration, collagen contraction, and transforming growth factor β-1 (TGF-β1)-induced myofibroblast differentiation were also analyzed. PDT affects the viability of VFFs in a dose-dependent manner. SL-PDT significantly changed the expression profile of VFFs with antifibrotic effects. It also inhibited cell migration, reduced collagen contraction, and reversed the fibroblast-myofibroblast differentiation induced by TGF-β1. SL-PDT induces antifibrotic alterations in VFFs. This could explain the low incidence of vocal fold scar associated with PDT. Moreover, PDT may be useful in treating existing vocal fold scars. Further studies should focus on the in vivo effect of PDT on vocal fold wound healing and scar remodeling. NA Laryngoscope, 2018. © 2018 The American Laryngological, Rhinological and Otological Society, Inc.

Mobile assemblies of Bennett linkages from four-crease origami patterns

Science.gov (United States)

Zhang, Xiao; Chen, Yan

2018-02-01

This paper deals with constructing mobile assemblies of Bennett linkages inspired by four-crease origami patterns. A transition technique has been proposed by taking the thick-panel form of an origami pattern as an intermediate bridge. A zero-thickness rigid origami pattern and its thick-panel form share the same sector angles and folding behaviours, while the thick-panel origami and the mobile assembly of linkages are kinematically equivalent with differences only in link profiles. Applying this transition technique to typical four-crease origami patterns, we have found that the Miura-ori and graded Miura-ori patterns lead to assemblies of Bennett linkages with identical link lengths. The supplementary-type origami patterns with different mountain-valley crease assignments correspond to different types of Bennett linkage assemblies with negative link lengths. And the identical linkage-type origami pattern generates a new mobile assembly. Hence, the transition technique offers a novel approach to constructing mobile assemblies of spatial linkages from origami patterns.

WHO: World Health Assembly.

Science.gov (United States)

McGregor, A

1992-05-23

1200 delegates from 175 member countries attended the 45th World Health Assembly in Geneva. Everyone at the Assembly ratified measures to prevent and control AIDS. 12 countries intended to do long term planning for community based care for AIDS patients. Further the Assembly denounced instances where countries and individuals denied the gravity of the AIDS pandemic. In fact, it expressed the importance for urgent and intensive action against HIV/AIDS. The assembly backed proposals to prevent and control sexually transmitted diseases that affect AIDS patients, especially hepatitis B. For example, in countries with hepatitis B prevalence 8% (many countries in Sub-Sahara Africa, Asia, the Pacific region, and South America), health officials should introduce hepatitis B vaccine into their existing immunization programs by 1995. By 1997, this vaccine should be part of all immunization programs. The Assembly was aware of the obstacles of establishing reliable cold chains for nationwide distribution, however. Delegates in Committee A objected to the fact that 50% of the populations of developing countries continued to have limited access to essential drugs. They also expressed disapproval in implementation of WHO's 1988 ethical criteria for promotion of drugs which WHO entrusted to the Council for International Organisations of Medical Sciences (CIOMS). CIOMS lacked WHO's status and thus could not effectively monitor drug advertising. In fact, the pharmaceutical industry as well as WHO provided the funds for a meeting of 25 experts to discuss principles included in the ethical criteria. At least 4 countries insisted that WHO have the ultimate authority in monitoring drug advertising. Delegates did adopt a compromise resolution on this topic which required that industry promotion methods be reported to the 1994 Assembly via the Executive Board. The Assembly requested WHO to establish an international advisory committee on nursing and midwifery and to improve the network of

Transcriptome Sequencing, De Novo Assembly and Differential Gene Expression Analysis of the Early Development of Acipenser baeri.

Directory of Open Access Journals (Sweden)

Wei Song

Full Text Available The molecular mechanisms that drive the development of the endangered fossil fish species Acipenser baeri are difficult to study due to the lack of genomic data. Recent advances in sequencing technologies and the reducing cost of sequencing offer exclusive opportunities for exploring important molecular mechanisms underlying specific biological processes. This manuscript describes the large scale sequencing and analyses of mRNA from Acipenser baeri collected at five development time points using the Illumina Hiseq2000 platform. The sequencing reads were de novo assembled and clustered into 278167 unigenes, of which 57346 (20.62% had 45837 known homologues proteins in Uniprot protein databases while 11509 proteins matched with at least one sequence of assembled unigenes. The remaining 79.38% of unigenes could stand for non-coding unigenes or unigenes specific to A. baeri. A number of 43062 unigenes were annotated into functional categories via Gene Ontology (GO annotation whereas 29526 unigenes were associated with 329 pathways by mapping to KEGG database. Subsequently, 3479 differentially expressed genes were scanned within developmental stages and clustered into 50 gene expression profiles. Genes preferentially expressed at each stage were also identified. Through GO and KEGG pathway enrichment analysis, relevant physiological variations during the early development of A. baeri could be better cognized. Accordingly, the present study gives insights into the transcriptome profile of the early development of A. baeri, and the information contained in this large scale transcriptome will provide substantial references for A. baeri developmental biology and promote its aquaculture research.

Tandem fusion of hepatitis B core antigen allows assembly of virus-like particles in bacteria and plants with enhanced capacity to accommodate foreign proteins.

Directory of Open Access Journals (Sweden)

Hadrien Peyret

Full Text Available The core protein of the hepatitis B virus, HBcAg, assembles into highly immunogenic virus-like particles (HBc VLPs when expressed in a variety of heterologous systems. Specifically, the major insertion region (MIR on the HBcAg protein allows the insertion of foreign sequences, which are then exposed on the tips of surface spike structures on the outside of the assembled particle. Here, we present a novel strategy which aids the display of whole proteins on the surface of HBc particles. This strategy, named tandem core, is based on the production of the HBcAg dimer as a single polypeptide chain by tandem fusion of two HBcAg open reading frames. This allows the insertion of large heterologous sequences in only one of the two MIRs in each spike, without compromising VLP formation. We present the use of tandem core technology in both plant and bacterial expression systems. The results show that tandem core particles can be produced with unmodified MIRs, or with one MIR in each tandem dimer modified to contain the entire sequence of GFP or of a camelid nanobody. Both inserted proteins are correctly folded and the nanobody fused to the surface of the tandem core particle (which we name tandibody retains the ability to bind to its cognate antigen. This technology paves the way for the display of natively folded proteins on the surface of HBc particles either through direct fusion or through non-covalent attachment via a nanobody.

Structure and assembly mechanism for heteromeric kainate receptors.

Science.gov (United States)

Kumar, Janesh; Schuck, Peter; Mayer, Mark L

2011-07-28

Native glutamate receptor ion channels are tetrameric assemblies containing two or more different subunits. NMDA receptors are obligate heteromers formed by coassembly of two or three divergent gene families. While some AMPA and kainate receptors can form functional homomeric ion channels, the KA1 and KA2 subunits are obligate heteromers which function only in combination with GluR5-7. The mechanisms controlling glutamate receptor assembly involve an initial step in which the amino terminal domains (ATD) assemble as dimers. Here, we establish by sedimentation velocity that the ATDs of GluR6 and KA2 coassemble as a heterodimer of K(d) 11 nM, 32,000-fold lower than the K(d) for homodimer formation by KA2; we solve crystal structures for the GluR6/KA2 ATD heterodimer and heterotetramer assemblies. Using these structures as a guide, we perform a mutant cycle analysis to probe the energetics of assembly and show that high-affinity ATD interactions are required for biosynthesis of functional heteromeric receptors. Copyright © 2011 Elsevier Inc. All rights reserved.

Overexpression of pucC improves the heterologous protein expression level in a Rhodobacter sphaeroides expression system.

Science.gov (United States)

Cheng, L; Chen, G; Ding, G; Zhao, Z; Dong, T; Hu, Z

2015-04-27

The Rhodobacter sphaeroides system has been used to express membrane proteins. However, its low yield has substantially limited its application. In order to promote the protein expression capability of this system, the pucC gene, which plays a crucial role in assembling the R. sphaeroides light-harvesting 2 complex (LH2), was overexpressed. To build a pucC overexpression strain, a pucC overexpression vector was constructed and transformed into R. sphaeroides CQU68. The overexpression efficiency was evaluated by quantitative real-time polymerase chain reaction. A well-used reporter β-glucuronidase (GUS) was fusion-expressed with LH2 to evaluate the heterologous protein expression level. As a result, the cell culture and protein in the pucC overexpression strain showed much higher typical spectral absorption peaks at 800 and 850 nm compared with the non-overexpression strain, suggesting a higher expression level of LH2-GUS fusion protein in the pucC overexpression strain. This result was further confirmed by Western blot, which also showed a much higher level of heterologous protein expression in the pucC overexpression strain. We further compared GUS activity in pucC overexpression and non-overexpression strains, the results of which showed that GUS activity in the pucC overexpression strain was approximately ten-fold that in the non-overexpression strain. These results demonstrate that overexpressed pucC can promote heterologous protein expression levels in R. sphaeroides.

N-fold Darboux Transformation for Integrable Couplings of AKNS Equations

Science.gov (United States)

Yu, Jing; Chen, Shou-Ting; Han, Jing-Wei; Ma, Wen-Xiu

2018-04-01

For the integrable couplings of Ablowitz-Kaup-Newell-Segur (ICAKNS) equations, N-fold Darboux transformation (DT) TN, which is a 4 × 4 matrix, is constructed in this paper. Each element of this matrix is expressed by a ratio of the (4N + 1)-order determinant and 4N-order determinant of eigenfunctions. By making use of these formulae, the determinant expressions of N-transformed new solutions p [N], q [N], r [N] and s [N] are generated by this N-fold DT. Furthermore, when the reduced conditions q = ‑p* and s = ‑r* are chosen, we obtain determinant representations of N-fold DT and N-transformed solutions for the integrable couplings of nonlinear Schrödinger (ICNLS) equations. Starting from the zero seed solutions, one-soliton solutions are explicitly given as an example. Supported by the National Natural Science Foundation of China under Grant Nos. 61771174, 11371326, 11371361, 11301454, and 11271168, Natural Science Fund for Colleges and Universities of Jiangsu Province of China under Grant No. 17KJB110020, and General Research Project of Department of Education of Zhejiang Province (Y201636538)

Exploiting the yeast L-A viral capsid for the in vivo assembly of chimeric VLPs as platform in vaccine development and foreign protein expression.

Directory of Open Access Journals (Sweden)

Frank Powilleit

Full Text Available A novel expression system based on engineered variants of the yeast (Saccharomyces cerevisiae dsRNA virus L-A was developed allowing the in vivo assembly of chimeric virus-like particles (VLPs as a unique platform for a wide range of applications. We show that polypeptides fused to the viral capsid protein Gag self-assemble into isometric VLP chimeras carrying their cargo inside the capsid, thereby not only effectively preventing proteolytic degradation in the host cell cytosol, but also allowing the expression of a per se cytotoxic protein. Carboxyterminal extension of Gag by T cell epitopes from human cytomegalovirus pp65 resulted in the formation of hybrid VLPs that strongly activated antigen-specific CD8(+ memory T cells ex vivo. Besides being a carrier for polypeptides inducing antigen-specific immune responses in vivo, VLP chimeras were also shown to be effective in the expression and purification of (i a heterologous model protein (GFP, (ii a per se toxic protein (K28 alpha-subunit, and (iii a particle-associated and fully recyclable biotechnologically relevant enzyme (esterase A. Thus, yeast viral Gag represents a unique platform for the in vivo assembly of chimeric VLPs, equally attractive and useful in vaccine development and recombinant protein production.

Vfold: a web server for RNA structure and folding thermodynamics prediction.

Science.gov (United States)

Xu, Xiaojun; Zhao, Peinan; Chen, Shi-Jie

2014-01-01

The ever increasing discovery of non-coding RNAs leads to unprecedented demand for the accurate modeling of RNA folding, including the predictions of two-dimensional (base pair) and three-dimensional all-atom structures and folding stabilities. Accurate modeling of RNA structure and stability has far-reaching impact on our understanding of RNA functions in human health and our ability to design RNA-based therapeutic strategies. The Vfold server offers a web interface to predict (a) RNA two-dimensional structure from the nucleotide sequence, (b) three-dimensional structure from the two-dimensional structure and the sequence, and (c) folding thermodynamics (heat capacity melting curve) from the sequence. To predict the two-dimensional structure (base pairs), the server generates an ensemble of structures, including loop structures with the different intra-loop mismatches, and evaluates the free energies using the experimental parameters for the base stacks and the loop entropy parameters given by a coarse-grained RNA folding model (the Vfold model) for the loops. To predict the three-dimensional structure, the server assembles the motif scaffolds using structure templates extracted from the known PDB structures and refines the structure using all-atom energy minimization. The Vfold-based web server provides a user friendly tool for the prediction of RNA structure and stability. The web server and the source codes are freely accessible for public use at "http://rna.physics.missouri.edu".

SAS-6 engineering reveals interdependence between cartwheel and microtubules in determining centriole architecture.

Science.gov (United States)

Hilbert, Manuel; Noga, Akira; Frey, Daniel; Hamel, Virginie; Guichard, Paul; Kraatz, Sebastian H W; Pfreundschuh, Moritz; Hosner, Sarah; Flückiger, Isabelle; Jaussi, Rolf; Wieser, Mara M; Thieltges, Katherine M; Deupi, Xavier; Müller, Daniel J; Kammerer, Richard A; Gönczy, Pierre; Hirono, Masafumi; Steinmetz, Michel O

2016-04-01

Centrioles are critical for the formation of centrosomes, cilia and flagella in eukaryotes. They are thought to assemble around a nine-fold symmetric cartwheel structure established by SAS-6 proteins. Here, we have engineered Chlamydomonas reinhardtii SAS-6-based oligomers with symmetries ranging from five- to ten-fold. Expression of a SAS-6 mutant that forms six-fold symmetric cartwheel structures in vitro resulted in cartwheels and centrioles with eight- or nine-fold symmetries in vivo. In combination with Bld10 mutants that weaken cartwheel-microtubule interactions, this SAS-6 mutant produced six- to eight-fold symmetric cartwheels. Concurrently, the microtubule wall maintained eight- and nine-fold symmetries. Expressing SAS-6 with analogous mutations in human cells resulted in nine-fold symmetric centrioles that exhibited impaired length and organization. Together, our data suggest that the self-assembly properties of SAS-6 instruct cartwheel symmetry, and lead us to propose a model in which the cartwheel and the microtubule wall assemble in an interdependent manner to establish the native architecture of centrioles.

Vocal Fold Paralysis

Science.gov (United States)

... here Home » Health Info » Voice, Speech, and Language Vocal Fold Paralysis On this page: What is vocal fold ... Where can I get additional information? What is vocal fold paralysis? Structures involved in speech and voice production ...

Dissection of β-barrel Outer Membrane Protein Assembly Pathways through Characterizing BamA POTRA 1 Mutants of Escherichia coli

Science.gov (United States)

Bennion, Drew; Charlson, Emily S.; Coon, Eric; Misra, Rajeev

2010-01-01

Summary BamA of Escherichia coli is an essential component of the hetero-oligomeric machinery that mediates β-barrel outer membrane protein (OMP) assembly. The C- and N-termini of BamA fold into trans-membrane β-barrel and five soluble POTRA domains, respectively. Detailed characterization of BamA POTRA 1 missense and deletion mutants revealed two competing OMP assembly pathways, one of which is followed by the archetypal trimeric β-barrel OMPs, OmpF and LamB, and is dependent on POTRA 1. Interestingly, our data suggest that BamA also requires its POTRA 1 domain for proper assembly. The second pathway is independent of POTRA 1 and is exemplified by TolC. Site-specific cross-linking analysis revealed that the POTRA 1 domain of BamA interacts with SurA, a periplasmic chaperone required for the assembly of OmpF and LamB, but not that of TolC and BamA. The data suggest that SurA and BamA POTRA 1 domain function in concert to assist folding and assembly of most β-barrel OMPs except for TolC, which folds into a unique soluble α-helical barrel and an OM-anchored β-barrel. The two assembly pathways finally merge at some step beyond POTRA 1 but presumably before membrane insertion, which is thought to be catalyzed by the trans-membrane β-barrel domain of Bam A. PMID:20598079

Earthworm Lumbricus rubellus MT-2: Metal Binding and Protein Folding of a True Cadmium-MT

Directory of Open Access Journals (Sweden)

Gregory R. Kowald

2016-01-01

Full Text Available Earthworms express, as most animals, metallothioneins (MTs—small, cysteine-rich proteins that bind d10 metal ions (Zn(II, Cd(II, or Cu(I in clusters. Three MT homologues are known for Lumbricus rubellus, the common red earthworm, one of which, wMT-2, is strongly induced by exposure of worms to cadmium. This study concerns composition, metal binding affinity and metal-dependent protein folding of wMT-2 expressed recombinantly and purified in the presence of Cd(II and Zn(II. Crucially, whilst a single Cd7wMT-2 species was isolated from wMT-2-expressing E. coli cultures supplemented with Cd(II, expressions in the presence of Zn(II yielded mixtures. The average affinities of wMT-2 determined for either Cd(II or Zn(II are both within normal ranges for MTs; hence, differential behaviour cannot be explained on the basis of overall affinity. Therefore, the protein folding properties of Cd- and Zn-wMT-2 were compared by 1H NMR spectroscopy. This comparison revealed that the protein fold is better defined in the presence of cadmium than in the presence of zinc. These differences in folding and dynamics may be at the root of the differential behaviour of the cadmium- and zinc-bound protein in vitro, and may ultimately also help in distinguishing zinc and cadmium in the earthworm in vivo.

Operon Gene Order Is Optimized for Ordered Protein Complex Assembly

Science.gov (United States)

Wells, Jonathan N.; Bergendahl, L. Therese; Marsh, Joseph A.

2016-01-01

Summary The assembly of heteromeric protein complexes is an inherently stochastic process in which multiple genes are expressed separately into proteins, which must then somehow find each other within the cell. Here, we considered one of the ways by which prokaryotic organisms have attempted to maximize the efficiency of protein complex assembly: the organization of subunit-encoding genes into operons. Using structure-based assembly predictions, we show that operon gene order has been optimized to match the order in which protein subunits assemble. Exceptions to this are almost entirely highly expressed proteins for which assembly is less stochastic and for which precisely ordered translation offers less benefit. Overall, these results show that ordered protein complex assembly pathways are of significant biological importance and represent a major evolutionary constraint on operon gene organization. PMID:26804901

Self-assembly from milli- to nanoscales: methods and applications

International Nuclear Information System (INIS)

Mastrangeli, M; Celis, J-P; Abbasi, S; Varel, C; Böhringer, K F; Van Hoof, C

2009-01-01

The design and fabrication techniques for microelectromechanical systems (MEMS) and nanodevices are progressing rapidly. However, due to material and process flow incompatibilities in the fabrication of sensors, actuators and electronic circuitry, a final packaging step is often necessary to integrate all components of a heterogeneous microsystem on a common substrate. Robotic pick-and-place, although accurate and reliable at larger scales, is a serial process that downscales unfavorably due to stiction problems, fragility and sheer number of components. Self-assembly, on the other hand, is parallel and can be used for device sizes ranging from millimeters to nanometers. In this review, the state-of-the-art in methods and applications for self-assembly is reviewed. Methods for assembling three-dimensional (3D) MEMS structures out of two-dimensional (2D) ones are described. The use of capillary forces for folding 2D plates into 3D structures, as well as assembling parts onto a common substrate or aggregating parts to each other into 2D or 3D structures, is discussed. Shape matching and guided assembly by magnetic forces and electric fields are also reviewed. Finally, colloidal self-assembly and DNA-based self-assembly, mainly used at the nanoscale, are surveyed, and aspects of theoretical modeling of stochastic assembly processes are discussed. (topical review)

Duck hepatitis A virus structural proteins expressed in insect cells self-assemble into virus-like particles with strong immunogenicity in ducklings.

Science.gov (United States)

Wang, Anping; Gu, Lingling; Wu, Shuang; Zhu, Shanyuan

2018-02-01

Duck hepatitis A virus (DHAV), a non-enveloped ssRNA virus, can cause a highly contagious disease in young ducklings. The three capsid proteins of VP0, VP1 and VP3 are translated within a single large open reading frame (ORF) and hydrolyzed by protease 3CD. However, little is known on whether the recombinant viral structural proteins (VPs) expressed in insect cells could spontaneously assemble into virus-like particles (VLPs) and whether these VLPs could induce protective immunity in young ducklings. To address these issues, the structural polyprotein precursor gene P1 and the protease gene 3CD were amplified by PCR, and the recombinant proteins were expressed in insect cells using a baculovirus expression system for the characterization of their structures and immunogenicity. The recombinant proteins expressed in Sf9 cells were detected by indirect immunofluorescence assay and Western blot analysis. Electron microscopy showed that the recombinant proteins spontaneously assembled into VLPs in insect cells. Western blot analysis of the purified VLPs revealed that the VLPs were composed with the three structural proteins. In addition, vaccination with the VLPs induced high humoral immune response and provided strong protection. Therefore, our findings may provide a framework for development of new vaccines for the prevention of duck viral hepatitis. Copyright © 2018 Elsevier B.V. All rights reserved.

Biomimetic self-assembly of a functional asymmetrical electronic device.

Science.gov (United States)

Boncheva, Mila; Gracias, David H; Jacobs, Heiko O; Whitesides, George M

2002-04-16

This paper introduces a biomimetic strategy for the fabrication of asymmetrical, three-dimensional electronic devices modeled on the folding of a chain of polypeptide structural motifs into a globular protein. Millimeter-size polyhedra-patterned with logic devices, wires, and solder dots-were connected in a linear string by using flexible wire. On self-assembly, the string folded spontaneously into two domains: one functioned as a ring oscillator, and the other one as a shift register. This example demonstrates that biomimetic principles of design and self-organization can be applied to generate multifunctional electronic systems of complex, three-dimensional architecture.

Molecular Precision at Micrometer Length Scales: Hierarchical Assembly of DNA-Protein Nanostructures.

Science.gov (United States)

Schiffels, Daniel; Szalai, Veronika A; Liddle, J Alexander

2017-07-25

Robust self-assembly across length scales is a ubiquitous feature of biological systems but remains challenging for synthetic structures. Taking a cue from biology-where disparate molecules work together to produce large, functional assemblies-we demonstrate how to engineer microscale structures with nanoscale features: Our self-assembly approach begins by using DNA polymerase to controllably create double-stranded DNA (dsDNA) sections on a single-stranded template. The single-stranded DNA (ssDNA) sections are then folded into a mechanically flexible skeleton by the origami method. This process simultaneously shapes the structure at the nanoscale and directs the large-scale geometry. The DNA skeleton guides the assembly of RecA protein filaments, which provides rigidity at the micrometer scale. We use our modular design strategy to assemble tetrahedral, rectangular, and linear shapes of defined dimensions. This method enables the robust construction of complex assemblies, greatly extending the range of DNA-based self-assembly methods.

Acute Acrolein Exposure Induces Impairment of Vocal Fold Epithelial Barrier Function.

Science.gov (United States)

Liu, Xinxin; Zheng, Wei; Sivasankar, M Preeti

2016-01-01

Acrolein is a ubiquitous pollutant abundant in cigarette smoke, mobile exhaust, and industrial waste. There is limited literature on the effects of acrolein on vocal fold tissue, although there are clinical reports of voice changes after pollutant exposures. Vocal folds are responsible for voice production. The overall objective of this study was to investigate the effects of acrolein exposure on viable, excised vocal fold epithelial tissue and to characterize the mechanism underlying acrolein toxicity. Vocal fold epithelia were studied because they form the outermost layer of the vocal folds and are a primary recipient of inhaled pollutants. Porcine vocal fold epithelia were exposed to 0, 50, 100, 500, 900 or 1300 μM of acrolein for 3 hours; the metabolic activity, epithelial resistance, epithelial permeability, tight junction protein (occludin and claudin 3) expression, cell membrane integrity and lipid peroxidation were investigated. The data demonstrated that acrolein exposure at 500 μM significantly reduced vocal fold epithelial metabolic activity by 27.2% (p≤0.001). Incubation with 100 μM acrolein caused a marked increase in epithelial permeability by 130.5% (pacrolein-treated samples, the cell membrane integrity was significantly damaged with a 45.6% increase of lipid peroxidation as compared to controls (pacrolein exposure impairs vocal fold epithelial barrier integrity. Lipid peroxidation-induced cell membrane damage may play an important role in reducing the barrier function of the epithelium.

An expression tag toolbox for microbial production of membrane bound plant cytochromes P450

DEFF Research Database (Denmark)

Vazquez Albacete, Dario; Cavaleiro, Mafalda; Christensen, Ulla

2017-01-01

of the intermediate and the final product of the pathway. Finally, the effect of a robustly performing expression tag was explored with a library of 49 different P450s from medicinal plants and nearly half of these were improved in expression by more than 2-fold. The developed toolbox serves as platform to tune P450...... tag chimeras of the model plant P450 CYP79A1 in different Escherichia coli strains. Using a high-throughput screening platform based on C-terminal GFP fusions, we identify several highly expressing and robustly performing chimeric designs. Analysis of long-term cultures by flow cytometry showed...... homogeneous populations for some of the conditions. Three chimeric designs were chosen for a more complex combinatorial assembly of a multigene pathway consisting of two P450s and a redox partner. Cells expressing these recombinant enzymes catalysed the conversion of the substrate to highly different ratios...

Association between Laryngeal Pepsin Levels and the Presence of Vocal Fold Polyps.

Science.gov (United States)

Wang, Lu; Tan, Jia-Jie; Wu, Ting; Zhang, Rui; Wu, Jia-Nuan; Zeng, Fang-Fang; Liu, You-Li; Han, Xiao-Yan; Li, Yan-Fei; Li, Xiang-Ping

2017-01-01

Objective To determine whether pepsin, the main component of refluxed gastric contents, is significantly associated with vocal fold polyps and to evaluate the diagnostic value of pepsin in vocal fold polyps' tissues. Study Design Cross-sectional study. Setting Nanfang Hospital of Southern Medical University. Subjects and Methods The study included 32 patients with vocal fold polyps and 16 healthy controls between 2011 and 2012. Reflux symptom index and reflux finding score assessments, 24-hour combined multichannel intraluminal impedance and pH monitoring, and biopsy of the vocal fold polyp tissues or posterior laryngeal mucosa (healthy controls) for immunohistochemical pepsin staining were performed. Results The expression of pepsin was significantly higher in patients with vocal fold polyps than in controls (28/32, 75% vs 5/16, 31.25%; P vocal fold polyps formation. In addition, pepsin immunohistochemical analysis of polyp biopsy samples appears to be a more sensitive and effective test for diagnosing laryngopharyngeal reflux than the reflux symptom index, the reflux finding score, and 24-hour pH monitoring in a clinical setting.

Assembly and multiple gene expression of thermophilic enzymes in Escherichia coli for in vitro metabolic engineering.

Science.gov (United States)

Ninh, Pham Huynh; Honda, Kohsuke; Sakai, Takaaki; Okano, Kenji; Ohtake, Hisao

2015-01-01

In vitro reconstitution of an artificial metabolic pathway is an emerging approach for the biocatalytic production of industrial chemicals. However, several enzymes have to be separately prepared (and purified) for the construction of an in vitro metabolic pathway, thereby limiting the practical applicability of this approach. In this study, genes encoding the nine thermophilic enzymes involved in a non-ATP-forming chimeric glycolytic pathway were assembled in an artificial operon and co-expressed in a single recombinant Escherichia coli strain. Gene expression levels of the thermophilic enzymes were controlled by their sequential order in the artificial operon. The specific activities of the recombinant enzymes in the cell-free extract of the multiple-gene-expression E. coli were 5.0-1,370 times higher than those in an enzyme cocktail prepared from a mixture of single-gene-expression strains, in each of which a single one of the nine thermophilic enzymes was overproduced. Heat treatment of a crude extract of the multiple-gene-expression cells led to the denaturation of indigenous proteins and one-step preparation of an in vitro synthetic pathway comprising only a limited number of thermotolerant enzymes. Coupling this in vitro pathway with other thermophilic enzymes including the H2 O-forming NADH oxidase or the malate/lactate dehydrogenase facilitated one-pot conversion of glucose to pyruvate or lactate, respectively. © 2014 Wiley Periodicals, Inc.

Goose parvovirus structural proteins expressed by recombinant baculoviruses self-assemble into virus-like particles with strong immunogenicity in goose.

Science.gov (United States)

Ju, Huanyu; Wei, Na; Wang, Qian; Wang, Chunyuan; Jing, Zhiqiang; Guo, Lu; Liu, Dapeng; Gao, Mingchun; Ma, Bo; Wang, Junwei

2011-05-27

Goose parvovirus (GPV), a small non-enveloped ssDNA virus, can cause Derzsy's disease, and three capsid proteins of VP1, VP2, and VP3 are encoded by an overlapping nucleotide sequence. However, little is known on whether recombinant viral proteins (VPs) could spontaneously assemble into virus-like particles (VLPs) in insect cells and whether these VLPs could retain their immunoreactivity and immunogenicity in susceptible geese. To address these issues, genes for these GPV VPs were amplified by PCR, and the recombinant VPs proteins were expressed in insect cells using a baculovirus expression system for the characterization of their structures, immunoreactivity, and immunogenicity. The rVP1, rVP2, and rVP3 expressed in Sf9 cells were detected by anti-GPV sera, anti-VP3 sera, and anti-His antibodies, respectively. Electron microscopy revealed that these rVPs spontaneously assembled into VLPs in insect cells, similar to that of the purified wild-type GPV virions. In addition, vaccination with individual types of VLPs, particularly with the rVP2-VLPs, induced higher titers of antibodies and neutralized different strains of GPVs in primary goose and duck embryo fibroblast cells in vitro. These data indicated that these VLPs retained immunoreactivity and had strong immunogenicity in susceptible geese. Therefore, our findings may provide a framework for development of new vaccines for the prevention of Derzsy's disease and vehicles for the delivery of drugs. Copyright © 2011 Elsevier Inc. All rights reserved.

Potassium titanyl phosphate laser-induced inflammatory response and extracellular matrix turnover in rabbit vocal fold scar.

Science.gov (United States)

Zhang, Jing; Zhen, Ruiqing; Wei, Chunsheng

2018-04-02

The objectives of this study were to observe the regulating effect of KTP laser and Nd:YAG laser in the repair of vocal fold scars. All rabbits were injured in the muscular layer with a sharp instrument, and then the vocal folds were treated with a KTP laser and a Nd:YAG laser at a power of 2, 4, 6 and 8 W 1 month after the injury. One month after treatment, the rabbits were killed and the throats were removed to detect changes in histology and gene expression of the vocal fold scar after laser therapy. The best efficacy of all KTP laser treatment groups was the KTP laser 6 W group. Regarding the detection of gene expression, in the KTP laser 6 W and Nd:YAG laser 6 W groups, col-3A1 was decreased compared to the scar group (P vocal fold scars have particular therapeutic effects. The KTP laser may be better than the Nd:YAG laser for the regulation of vocal fold scars. NA.

Myonuclear domain size and myosin isoform expression in muscle fibres from mammals representing a 100,000-fold difference in body size.

Science.gov (United States)

Liu, Jing-Xia; Höglund, Anna-Stina; Karlsson, Patrick; Lindblad, Joakim; Qaisar, Rizwan; Aare, Sudhakar; Bengtsson, Ewert; Larsson, Lars

2009-01-01

This comparative study of myonuclear domain (MND) size in mammalian species representing a 100,000-fold difference in body mass, ranging from 25 g to 2500 kg, was undertaken to improve our understanding of myonuclear organization in skeletal muscle fibres. Myonuclear domain size was calculated from three-dimensional reconstructions in a total of 235 single muscle fibre segments at a fixed sarcomere length. Irrespective of species, the largest MND size was observed in muscle fibres expressing fast myosin heavy chain (MyHC) isoforms, but in the two smallest mammalian species studied (mouse and rat), MND size was not larger in the fast-twitch fibres expressing the IIA MyHC isofom than in the slow-twitch type I fibres. In the larger mammals, the type I fibres always had the smallest average MND size, but contrary to mouse and rat muscles, type IIA fibres had lower mitochondrial enzyme activities than type I fibres. Myonuclear domain size was highly dependent on body mass in the two muscle fibre types expressed in all species, i.e. types I and IIA. Myonuclear domain size increased in muscle fibres expressing both the beta/slow (type I; r = 0.84, P fast IIA MyHC isoform (r = 0.90; P muscle fibre type, independent of species. However, myosin isoform expression is not the sole protein determining MND size, and other protein systems, such as mitochondrial proteins, may be equally or more important determinants of MND size.

A dominant TRPV4 variant underlies osteochondrodysplasia in Scottish fold cats.

Science.gov (United States)

Gandolfi, B; Alamri, S; Darby, W G; Adhikari, B; Lattimer, J C; Malik, R; Wade, C M; Lyons, L A; Cheng, J; Bateman, J F; McIntyre, P; Lamandé, S R; Haase, B

2016-08-01

Scottish fold cats, named for their unique ear shape, have a dominantly inherited osteochondrodysplasia involving malformation in the distal forelimbs, distal hindlimbs and tail, and progressive joint destruction. This study aimed to identify the gene and the underlying variant responsible for the osteochondrodysplasia. DNA samples from 44 Scottish fold and 54 control cats were genotyped using a feline DNA array and a case-control genome-wide association analysis conducted. The gene encoding a calcium permeable ion channel, transient receptor potential cation channel, subfamily V, member 4 (TRPV4) was identified as a candidate within the associated region and sequenced. Stably transfected HEK293 cells were used to compare wild-type and mutant TRPV4 expression, cell surface localisation and responses to activation with a synthetic agonist GSK1016709A, hypo-osmolarity, and protease-activated receptor 2 stimulation. The dominantly inherited folded ear and osteochondrodysplasia in Scottish fold cats is associated with a p.V342F substitution (c.1024G>T) in TRPV4. The change was not found in 648 unaffected cats. Functional analysis in HEK293 cells showed V342F mutant TRPV4 was poorly expressed at the cell surface compared to wild-type TRPV4 and as a consequence the maximum response to a synthetic agonist was reduced. Mutant TRPV4 channels had a higher basal activity and an increased response to hypotonic conditions. Access to a naturally-occurring TRPV4 mutation in the Scottish fold cat will allow further functional studies to identify how and why the mutations affect cartilage and bone development. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Partial wave analysis for folded differential cross sections

Science.gov (United States)

Machacek, J. R.; McEachran, R. P.

2018-03-01

The value of modified effective range theory (MERT) and the connection between differential cross sections and phase shifts in low-energy electron scattering has long been recognized. Recent experimental techniques involving magnetically confined beams have introduced the concept of folded differential cross sections (FDCS) where the forward (θ ≤ π/2) and backward scattered (θ ≥ π/2) projectiles are unresolved, that is the value measured at the angle θ is the sum of the signal for particles scattered into the angles θ and π - θ. We have developed an alternative approach to MERT in order to analyse low-energy folded differential cross sections for positrons and electrons. This results in a simplified expression for the FDCS when it is expressed in terms of partial waves and thereby enables one to extract the first few phase shifts from a fit to an experimental FDCS at low energies. Thus, this method predicts forward and backward angle scattering (0 to π) using only experimental FDCS data and can be used to determine the total elastic cross section solely from experimental results at low-energy, which are limited in angular range.

Expression of human ferredoxin and assembly of the [2Fe-2S] center in Escherichia coli

International Nuclear Information System (INIS)

Coghlan, V.M.; Vickery, L.E.

1989-01-01

A cDNA fragment encoding human ferredoxin, a mitochondrial [2Fe-2S] protein, was introduced into Escherichia coli by using an expression vector based on the approach of Nagai and Thogersen. Expression was under control of the λP L promoter and resulted in production of ferredoxin as a cleavable fusion protein with an amino-terminal fragment derived from bacteriophage λcII protein. The fusion protein was isolated from the soluble fraction of induced cells and was specifically cleaved to yield mature recombinant ferredoxin. The recombinant protein was shown to be identical in size to ferredoxin isolated from human placenta (13,546 Da) by NaDodSO 4 /PAGE and partial amino acid sequencing. E. coli cells expressing human ferredoxin were brown in color, and absorbance and electron paramagnetic resonance spectra of the purified recombinant protein established that the [2Fe-2S]center was assembled and incorporated into ferredoxin in vivo. Recombinant ferredoxin was active in steroid hydroxylations when reconstituted with cytochromes P-450 sec and P-450 11β and exhibited rates comparable to those observed for ferredoxin isolated from human placenta. This expression system should be useful in production of native and structurally altered forms of human ferredoxin for studies of ferredoxin structure and function

Expression, purification, crystallization and preliminary X-ray characterization of a putative glycosyltransferase of the GT-A fold found in mycobacteria

Energy Technology Data Exchange (ETDEWEB)

Fulton, Zara [The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia); Crellin, Paul K.; Brammananth, Rajini [Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia); Department of Microbiology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Zaker-Tabrizi, Leyla [The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia); Coppel, Ross L. [Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia); Department of Microbiology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Rossjohn, Jamie, E-mail: jamie.rossjohn@med.monash.edu.au; Beddoe, Travis, E-mail: jamie.rossjohn@med.monash.edu.au [The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia)

2008-05-01

MAP2569c from M. avium subsp. paratuberculosis, a putative glycosyltransferase implicated in mycobacterial cell-wall biosynthesis, was cloned, expressed, purified and crystallized. X-ray diffraction data were collected to 1.8 Å resolution. Glycosidic bond formation is a ubiquitous enzyme-catalysed reaction. This glycosyltransferase-mediated process is responsible for the biosynthesis of innumerable oligosaccharides and glycoconjugates and is often organism- or cell-specific. However, despite the abundance of genomic information on glycosyltransferases (GTs), there is a lack of structural data for this versatile class of enzymes. Here, the cloning, expression, purification and crystallization of an essential 329-amino-acid (34.8 kDa) putative GT of the classic GT-A fold implicated in mycobacterial cell-wall biosynthesis are reported. Crystals of MAP2569c from Mycobacterium avium subsp. paratuberculosis were grown in 1.6 M monoammonium dihydrogen phosphate and 0.1 M sodium citrate pH 5.5. A complete data set was collected to 1.8 Å resolution using synchrotron radiation from a crystal belonging to space group P4{sub 1}2{sub 1}2.

Expression, purification, crystallization and preliminary X-ray characterization of a putative glycosyltransferase of the GT-A fold found in mycobacteria

International Nuclear Information System (INIS)

Fulton, Zara; Crellin, Paul K.; Brammananth, Rajini; Zaker-Tabrizi, Leyla; Coppel, Ross L.; Rossjohn, Jamie; Beddoe, Travis

2008-01-01

MAP2569c from M. avium subsp. paratuberculosis, a putative glycosyltransferase implicated in mycobacterial cell-wall biosynthesis, was cloned, expressed, purified and crystallized. X-ray diffraction data were collected to 1.8 Å resolution. Glycosidic bond formation is a ubiquitous enzyme-catalysed reaction. This glycosyltransferase-mediated process is responsible for the biosynthesis of innumerable oligosaccharides and glycoconjugates and is often organism- or cell-specific. However, despite the abundance of genomic information on glycosyltransferases (GTs), there is a lack of structural data for this versatile class of enzymes. Here, the cloning, expression, purification and crystallization of an essential 329-amino-acid (34.8 kDa) putative GT of the classic GT-A fold implicated in mycobacterial cell-wall biosynthesis are reported. Crystals of MAP2569c from Mycobacterium avium subsp. paratuberculosis were grown in 1.6 M monoammonium dihydrogen phosphate and 0.1 M sodium citrate pH 5.5. A complete data set was collected to 1.8 Å resolution using synchrotron radiation from a crystal belonging to space group P4 1 2 1 2

Efficient expression of functional (α6β22β3 AChRs in Xenopus oocytes from free subunits using slightly modified α6 subunits.

Directory of Open Access Journals (Sweden)

Carson Kai-Kwong Ley

Full Text Available Human (α6β2(α4β2β3 nicotinic acetylcholine receptors (AChRs are essential for addiction to nicotine and a target for drug development for smoking cessation. Expressing this complex AChR is difficult, but has been achieved using subunit concatamers. In order to determine what limits expression of α6* AChRs and to efficiently express α6* AChRs using free subunits, we investigated expression of the simpler (α6β22β3 AChR. The concatameric form of this AChR assembles well, but is transported to the cell surface inefficiently. Various chimeras of α6 with the closely related α3 subunit increased expression efficiency with free subunits and produced pharmacologically equivalent functional AChRs. A chimera in which the large cytoplasmic domain of α6 was replaced with that of α3 increased assembly with β2 subunits and transport of AChRs to the oocyte surface. Another chimera replacing the unique methionine 211 of α6 with leucine found at this position in transmembrane domain 1 of α3 and other α subunits increased assembly of mature subunits containing β3 subunits within oocytes. Combining both α3 sequences in an α6 chimera increased expression of functional (α6β22β3 AChRs to 12-fold more than with concatamers. This is pragmatically useful, and provides insights on features of α6 subunit structure that limit its expression in transfected cells.

The Nucleosome Assembly Activity of NAP1 Is Enhanced by Alien▿

OpenAIRE

Eckey, Maren; Hong, Wei; Papaioannou, Maria; Baniahmad, Aria

2007-01-01

The assembly of nucleosomes into chromatin is essential for the compaction of DNA and inactivation of the DNA template to modulate and repress gene expression. The nucleosome assembly protein 1, NAP1, assembles nucleosomes independent of DNA synthesis and was shown to enhance coactivator-mediated gene expression, suggesting a role for NAP1 in transcriptional regulation. Here, we show that Alien, known to harbor characteristics of a corepressor of nuclear hormone receptors such as of the vitam...

Notch-dependent epithelial fold determines boundary formation between developmental fields in the Drosophila antenna.

Science.gov (United States)

Ku, Hui-Yu; Sun, Y Henry

2017-07-01

Compartment boundary formation plays an important role in development by separating adjacent developmental fields. Drosophila imaginal discs have proven valuable for studying the mechanisms of boundary formation. We studied the boundary separating the proximal A1 segment and the distal segments, defined respectively by Lim1 and Dll expression in the eye-antenna disc. Sharp segregation of the Lim1 and Dll expression domains precedes activation of Notch at the Dll/Lim1 interface. By repressing bantam miRNA and elevating the actin regulator Enable, Notch signaling then induces actomyosin-dependent apical constriction and epithelial fold. Disruption of Notch signaling or the actomyosin network reduces apical constriction and epithelial fold, so that Dll and Lim1 cells become intermingled. Our results demonstrate a new mechanism of boundary formation by actomyosin-dependent tissue folding, which provides a physical barrier to prevent mixing of cells from adjacent developmental fields.

Accelerated Development of Supramolecular Corneal Stromal-Like Assemblies from Corneal Fibroblasts in the Presence of Macromolecular Crowders.

Science.gov (United States)

Kumar, Pramod; Satyam, Abhigyan; Fan, Xingliang; Rochev, Yury; Rodriguez, Brian J; Gorelov, Alexander; Joshi, Lokesh; Raghunath, Michael; Pandit, Abhay; Zeugolis, Dimitrios I

2015-07-01

Tissue engineering by self-assembly uses the cells' secretome as a regeneration template and biological factory of trophic factors. Despite the several advantages that have been witnessed in preclinical and clinical settings, the major obstacle for wide acceptance of this technology remains the tardy extracellular matrix formation. In this study, we assessed the influence of macromolecular crowding (MMC)/excluding volume effect, a biophysical phenomenon that accelerates thermodynamic activities and biological processes by several orders of magnitude, in human corneal fibroblast (HCF) culture. Our data indicate that the addition of negatively charged galactose derivative (carrageenan) in HCF culture, even at 0.5% serum, increases by 12-fold tissue-specific matrix deposition, while maintaining physiological cell morphology and protein/gene expression. Gene analysis indicates that a glucose derivative (dextran sulfate) may drive corneal fibroblasts toward a myofibroblast lineage. Collectively, these results indicate that MMC may be suitable not only for clinical translation and commercialization of tissue engineering by self-assembly therapies, but also for the development of in vitro pathophysiology models.

Fold maps and positive topological quantum field theories

Energy Technology Data Exchange (ETDEWEB)

Wrazidlo, Dominik Johannes

2017-04-12

The notion of positive TFT as coined by Banagl is specified by an axiomatic system based on Atiyah's original axioms for TFTs. By virtue of a general framework that is based on the concept of Eilenberg completeness of semirings from computer science, a positive TFT can be produced rigorously via quantization of systems of fields and action functionals - a process inspired by Feynman's path integral from classical quantum field theory. The purpose of the present dissertation thesis is to investigate a new differential topological invariant for smooth manifolds that arises as the state sum of the fold map TFT, which has been constructed by Banagl as a example of a positive TFT. By eliminating an internal technical assumption on the fields of the fold map TFT, we are able to express the informational content of the state sum in terms of an extension problem for fold maps from cobordisms into the plane. Next, we use the general theory of generic smooth maps into the plane to improve known results about the structure of the state sum in arbitrary dimensions, and to determine it completely in dimension two. The aggregate invariant of a homotopy sphere, which is derived from the state sum, naturally leads us to define a filtration of the group of homotopy spheres in order to understand the role of indefinite fold lines beyond a theorem of Saeki. As an application, we show how Kervaire spheres can be characterized by indefinite fold lines in certain dimensions.

De novo transcriptome assembly and quantification reveal differentially expressed genes between soft-seed and hard-seed pomegranate (Punica granatum L..

Directory of Open Access Journals (Sweden)

Hui Xue

Full Text Available Pomegranate (Punica granatum L. belongs to Punicaceae, and is valued for its social, ecological, economic, and aesthetic values, as well as more recently for its health benefits. The 'Tunisia' variety has softer seeds and big arils that are easily swallowed. It is a widely popular fruit; however, the molecular mechanisms of the formation of hard and soft seeds is not yet clear. We conducted a de novo assembly of the seed transcriptome in P. granatum L. and revealed differential gene expression between the soft-seed and hard-seed pomegranate varieties. A total of 35.1 Gb of data were acquired in this study, including 280,881,106 raw reads. Additionally, de novo transcriptome assembly generated 132,287 transcripts and 105,743 representative unigenes; approximately 13,805 unigenes (37.7% were longer than 1,000 bp. Using bioinformatics annotation libraries, a total of 76,806 unigenes were annotated and, among the high-quality reads, 72.63% had at least one significant match to an existing gene model. Gene expression and differentially expressed genes were analyzed. The seed formation of the two pomegranate cultivars involves lignin biosynthesis and metabolism, including some genes encoding laccase and peroxidase, WRKY, MYB, and NAC transcription factors. In the hard-seed pomegranate, lignin-related genes and cellulose synthesis-related genes were highly expressed; in soft-seed pomegranates, expression of genes related to flavonoids and programmed cell death was slightly higher. We validated selection of the identified genes using qRT-PCR. This is the first transcriptome analysis of P. granatum L. This transcription sequencing greatly enriched the pomegranate molecular database, and the high-quality SSRs generated in this study will aid the gene cloning from pomegranate in the future. It provides important insights into the molecular mechanisms underlying the formation of soft seeds in pomegranate.

De novo transcriptome assembly and quantification reveal differentially expressed genes between soft-seed and hard-seed pomegranate (Punica granatum L.).

Science.gov (United States)

Xue, Hui; Cao, Shangyin; Li, Haoxian; Zhang, Jie; Niu, Juan; Chen, Lina; Zhang, Fuhong; Zhao, Diguang

2017-01-01

Pomegranate (Punica granatum L.) belongs to Punicaceae, and is valued for its social, ecological, economic, and aesthetic values, as well as more recently for its health benefits. The 'Tunisia' variety has softer seeds and big arils that are easily swallowed. It is a widely popular fruit; however, the molecular mechanisms of the formation of hard and soft seeds is not yet clear. We conducted a de novo assembly of the seed transcriptome in P. granatum L. and revealed differential gene expression between the soft-seed and hard-seed pomegranate varieties. A total of 35.1 Gb of data were acquired in this study, including 280,881,106 raw reads. Additionally, de novo transcriptome assembly generated 132,287 transcripts and 105,743 representative unigenes; approximately 13,805 unigenes (37.7%) were longer than 1,000 bp. Using bioinformatics annotation libraries, a total of 76,806 unigenes were annotated and, among the high-quality reads, 72.63% had at least one significant match to an existing gene model. Gene expression and differentially expressed genes were analyzed. The seed formation of the two pomegranate cultivars involves lignin biosynthesis and metabolism, including some genes encoding laccase and peroxidase, WRKY, MYB, and NAC transcription factors. In the hard-seed pomegranate, lignin-related genes and cellulose synthesis-related genes were highly expressed; in soft-seed pomegranates, expression of genes related to flavonoids and programmed cell death was slightly higher. We validated selection of the identified genes using qRT-PCR. This is the first transcriptome analysis of P. granatum L. This transcription sequencing greatly enriched the pomegranate molecular database, and the high-quality SSRs generated in this study will aid the gene cloning from pomegranate in the future. It provides important insights into the molecular mechanisms underlying the formation of soft seeds in pomegranate.

A Molecular Staple: D-Loops in the I Domain of Bacteriophage P22 Coat Protein Make Important Intercapsomer Contacts Required for Procapsid Assembly

Science.gov (United States)

D'Lima, Nadia G.

2015-01-01

ABSTRACT Bacteriophage P22, a double-stranded DNA (dsDNA) virus, has a nonconserved 124-amino-acid accessory domain inserted into its coat protein, which has the canonical HK97 protein fold. This I domain is involved in virus capsid size determination and stability, as well as protein folding. The nuclear magnetic resonance (NMR) solution structure of the I domain revealed the presence of a D-loop, which was hypothesized to make important intersubunit contacts between coat proteins in adjacent capsomers. Here we show that amino acid substitutions of residues near the tip of the D-loop result in aberrant assembly products, including tubes and broken particles, highlighting the significance of the D-loops in proper procapsid assembly. Using disulfide cross-linking, we showed that the tips of the D-loops are positioned directly across from each other both in the procapsid and the mature virion, suggesting their importance in both states. Our results indicate that D-loop interactions act as “molecular staples” at the icosahedral 2-fold symmetry axis and significantly contribute to stabilizing the P22 capsid for DNA packaging. IMPORTANCE Many dsDNA viruses have morphogenic pathways utilizing an intermediate capsid, known as a procapsid. These procapsids are assembled from a coat protein having the HK97 fold in a reaction driven by scaffolding proteins or delta domains. Maturation of the capsid occurs during DNA packaging. Bacteriophage HK97 uniquely stabilizes its capsid during maturation by intercapsomer cross-linking, but most virus capsids are stabilized by alternate means. Here we show that the I domain that is inserted into the coat protein of bacteriophage P22 is important in the process of proper procapsid assembly. Specifically, the I domain allows for stabilizing interactions across the capsid 2-fold axis of symmetry via a D-loop. When amino acid residues at the tip of the D-loop are mutated, aberrant assembly products, including tubes, are formed instead

Mesenchymal stromal cell injection promotes vocal fold scar repair without long-term engraftment

Science.gov (United States)

BARTLETT, R.S.; GUILLE, J.T.; CHEN, X.; CHRISTENSEN, M.B.; WANG, S.F.; THIBEAULT, S.L.

2016-01-01

Background Regenerative medicine holds promise for restoring voice in patients with vocal fold scarring. As experimental treatments approach clinical translation, several considerations remain. Our objective was to evaluate efficacy and biocompatibility of four bone marrow mesenchymal stromal cell (BM-MSC) and tunable hyaluronic acid based hydrogel (HyStem-VF) treatments for vocal fold scar using clinically acceptable materials, a preclinical sample size and a dosing comparison. Methods Vocal folds of 84 rabbits were injured and injected with four treatment variations (BM-MSC, HyStem-VF, and BM-MSC in HyStem-VF at two concentrations) 6 weeks later. Efficacy was assessed with rheometry, real-time polymerase chain reaction (PCR) and histology at 2, 4 and 10 weeks following treatment. Lung, liver, kidney, spleen and vocal folds were screened for biocompatibility by a pathologist. Results and discussion Persistent inflammation was identified in all hydrogel-injected groups. The BM-MSC alone treatment appeared to be the most efficacious and safe, providing an early resolution of viscoelasticity, gene expression consistent with desirable extracellular matrix remodeling (less fibronectin, collagen 1α2, collagen 3, procollagen, transforming growth factor [TGF]β1, alpha smooth muscle actin, interleukin-1β, interleukin-17β and tumor necrosis factor [TNF] than injured controls) and minimal inflammation. Human beta actin expression in BM-MSC–treated vocal folds was minimal after 2 weeks, suggesting that paracrine signaling from the BM-MSCs may have facilitated tissue repair. PMID:27637759

General Assembly

CERN Multimedia

Staff Association

2016-01-01

5th April, 2016 – Ordinary General Assembly of the Staff Association! In the first semester of each year, the Staff Association (SA) invites its members to attend and participate in the Ordinary General Assembly (OGA). This year the OGA will be held on Tuesday, April 5th 2016 from 11:00 to 12:00 in BE Auditorium, Meyrin (6-2-024). During the Ordinary General Assembly, the activity and financial reports of the SA are presented and submitted for approval to the members. This is the occasion to get a global view on the activities of the SA, its financial management, and an opportunity to express one’s opinion, including taking part in the votes. Other points are listed on the agenda, as proposed by the Staff Council. Who can vote? Only “ordinary” members (MPE) of the SA can vote. Associated members (MPA) of the SA and/or affiliated pensioners have a right to vote on those topics that are of direct interest to them. Who can give his/her opinion? The Ordinary General Asse...

Nonlinear dynamics of spring softening and hardening in folded-mems comb drive resonators

KAUST Repository

Elshurafa, Amro M.; Khirallah, Kareem; Tawfik, Hani H.; Emira, Ahmed; Abdel Aziz, Ahmed K S; Sedky, Sherif M.

2011-01-01

This paper studies analytically and numerically the spring softening and hardening phenomena that occur in electrostatically actuated microelectromechanical systems comb drive resonators utilizing folded suspension beams. An analytical expression

SpRoUTS (Space Robot Universal Truss System): Reversible Robotic Assembly of Deployable Truss Structures of Reconfigurable Length

Science.gov (United States)

Jenett, Benjamin; Cellucci, Daniel; Cheung, Kenneth

2015-01-01

Automatic deployment of structures has been a focus of much academic and industrial work on infrastructure applications and robotics in general. This paper presents a robotic truss assembler designed for space applications - the Space Robot Universal Truss System (SpRoUTS) - that reversibly assembles a truss from a feedstock of hinged andflat-packed components, by folding the sides of each component up and locking onto the assembled structure. We describe the design and implementation of the robot and show that the assembled truss compares favorably with prior truss deployment systems.

Studies of G-quadruplexes formed within self-assembled DNA mini-circles.

Science.gov (United States)

Klejevskaja, Beata; Pyne, Alice L B; Reynolds, Matthew; Shivalingam, Arun; Thorogate, Richard; Hoogenboom, Bart W; Ying, Liming; Vilar, Ramon

2016-10-13

We have developed self-assembled DNA mini-circles that contain a G-quadruplex-forming sequence from the c-Myc oncogene promoter and demonstrate by FRET that the G-quadruplex unfolding kinetics are 10-fold slower than for the simpler 24-mer G-quadruplex that is commonly used for FRET experiments.

NEDDylation promotes stress granule assembly.

Science.gov (United States)

Jayabalan, Aravinth Kumar; Sanchez, Anthony; Park, Ra Young; Yoon, Sang Pil; Kang, Gum-Yong; Baek, Je-Hyun; Anderson, Paul; Kee, Younghoon; Ohn, Takbum

2016-07-06

Stress granules (SGs) harbour translationally stalled messenger ribonucleoproteins and play important roles in regulating gene expression and cell fate. Here we show that neddylation promotes SG assembly in response to arsenite-induced oxidative stress. Inhibition or depletion of key components of the neddylation machinery concomitantly inhibits stress-induced polysome disassembly and SG assembly. Affinity purification and subsequent mass-spectrometric analysis of Nedd8-conjugated proteins from translationally stalled ribosomal fractions identified ribosomal proteins, translation factors and RNA-binding proteins (RBPs), including SRSF3, a previously known SG regulator. We show that SRSF3 is selectively neddylated at Lys85 in response to arsenite. A non-neddylatable SRSF3 (K85R) mutant do not prevent arsenite-induced polysome disassembly, but fails to support the SG assembly, suggesting that the neddylation pathway plays an important role in SG assembly.

Improving protein fold recognition by extracting fold-specific features from predicted residue-residue contacts.

Science.gov (United States)

Zhu, Jianwei; Zhang, Haicang; Li, Shuai Cheng; Wang, Chao; Kong, Lupeng; Sun, Shiwei; Zheng, Wei-Mou; Bu, Dongbo

2017-12-01

Accurate recognition of protein fold types is a key step for template-based prediction of protein structures. The existing approaches to fold recognition mainly exploit the features derived from alignments of query protein against templates. These approaches have been shown to be successful for fold recognition at family level, but usually failed at superfamily/fold levels. To overcome this limitation, one of the key points is to explore more structurally informative features of proteins. Although residue-residue contacts carry abundant structural information, how to thoroughly exploit these information for fold recognition still remains a challenge. In this study, we present an approach (called DeepFR) to improve fold recognition at superfamily/fold levels. The basic idea of our approach is to extract fold-specific features from predicted residue-residue contacts of proteins using deep convolutional neural network (DCNN) technique. Based on these fold-specific features, we calculated similarity between query protein and templates, and then assigned query protein with fold type of the most similar template. DCNN has showed excellent performance in image feature extraction and image recognition; the rational underlying the application of DCNN for fold recognition is that contact likelihood maps are essentially analogy to images, as they both display compositional hierarchy. Experimental results on the LINDAHL dataset suggest that even using the extracted fold-specific features alone, our approach achieved success rate comparable to the state-of-the-art approaches. When further combining these features with traditional alignment-related features, the success rate of our approach increased to 92.3%, 82.5% and 78.8% at family, superfamily and fold levels, respectively, which is about 18% higher than the state-of-the-art approach at fold level, 6% higher at superfamily level and 1% higher at family level. An independent assessment on SCOP_TEST dataset showed consistent

Mobile work station concept for assembly of large space structures (zero gravity simulation tests)

Science.gov (United States)

Heard, W. L., Jr.; Bush, H. G.; Wallsom, R. E.; Jensen, J. K.

1982-03-01

The concept presented is intended to enhance astronaut assembly of truss structure that is either too large or complex to fold for efficient Shuttle delivery to orbit. The potential of augmented astronaut assembly is illustrated by applying the result of the tests to a barebones assembly of a truss structure. If this structure were assembled from the same nestable struts that were used in the Mobile Work Station assembly tests, the spacecraft would be 55 meters in diameter and consist of about 500 struts. The struts could be packaged in less than 1/2% of the Shuttle cargo bay volume and would take up approximately 3% of the mass lift capability. They could be assembled in approximately four hours. This assembly concept for erectable structures is not only feasible, but could be used to significant economic advantage by permitting the superior packaging feature of erectable structures to be exploited and thereby reduce expensive Shuttle delivery flights.

Biologic Constraints on Modelling Virus Assembly

Directory of Open Access Journals (Sweden)

Robert L. Garcea

2008-01-01

Full Text Available The mathematic modelling of icosahedral virus assembly has drawn increasing interest because of the symmetric geometry of the outer shell structures. Many models involve equilibrium expressions of subunit binding, with reversible subunit additions forming various intermediate structures. The underlying assumption is that a final lowest energy state drives the equilibrium toward assembly. In their simplest forms, these models have explained why high subunit protein concentrations and strong subunit association constants can result in kinetic traps forming off pathway partial and aberrant structures. However, the cell biology of virus assembly is exceedingly complex. The biochemistry and biology of polyoma and papillomavirus assembly described here illustrates many of these specific issues. Variables include the use of cellular ‘chaperone’ proteins as mediators of assembly fidelity, the coupling of assembly to encapsidation of a specific nucleic acid genome, the use of cellular structures as ‘workbenches’ upon which assembly occurs, and the underlying problem of making a capsid structure that is metastable and capable of rapid disassembly upon infection. Although formidable to model, incorporating these considerations could advance the relevance of mathematical models of virus assembly to the real world.

Non-cylindrical fold growth in the Zagros fold and thrust belt (Kurdistan, NE-Iraq)

Science.gov (United States)

Bartl, Nikolaus; Bretis, Bernhard; Grasemann, Bernhard; Lockhart, Duncan

2010-05-01

The Zagros mountains extends over 1800 km from Kurdistan in N-Iraq to the Strait of Hormuz in Iran and is one of the world most promising regions for the future hydrocarbon exploration. The Zagros Mountains started to form as a result of the collision between the Eurasian and Arabian Plates, whose convergence began in the Late Cretaceous as part of the Alpine-Himalayan orogenic system. Geodetic and seismological data document that both plates are still converging and that the fold and thrust belt of the Zagros is actively growing. Extensive hydrocarbon exploration mainly focuses on the antiforms of this fold and thrust belt and therefore the growth history of the folds is of great importance. This work investigates by means of structural field work and quantitative geomorphological techniques the progressive fold growth of the Permam, Bana Bawi- and Safeen- Anticlines located in the NE of the city of Erbil in the Kurdistan region of Northern Iraq. This part of the Zagros fold and thrust belt belongs to the so-called Simply Folded Belt, which is dominated by gentle to open folding. Faults or fault related folds have only minor importance. The mechanical anisotropy of the formations consisting of a succession of relatively competent (massive dolomite and limestone) and incompetent (claystone and siltstone) sediments essentially controls the deformation pattern with open to gentle parallel folding of the competent layers and flexural flow folding of the incompetent layers. The characteristic wavelength of the fold trains is around 10 km. Due to faster erosion of the softer rock layers in the folded sequence, the more competent lithologies form sharp ridges with steeply sloping sides along the eroded flanks of the anticlines. Using an ASTER digital elevation model in combination with geological field data we quantified 250 drainage basins along the different limbs of the subcylindrical Permam, Bana Bawi- and Safeen- Anticlines. Geomorphological indices of the drainage

De novo transcriptome assembly and analysis of differential gene expression in response to drought in European beech.

Directory of Open Access Journals (Sweden)

Markus Müller

Full Text Available Despite the ecological and economic importance of European beech (Fagus sylvatica L. genomic resources of this species are still limited. This hampers an understanding of the molecular basis of adaptation to stress. Since beech will most likely be threatened by the consequences of climate change, an understanding of adaptive processes to climate change-related drought stress is of major importance. Here, we used RNA-seq to provide the first drought stress-related transcriptome of beech. In a drought stress trial with beech saplings, 50 samples were taken for RNA extraction at five points in time during a soil desiccation experiment. De novo transcriptome assembly and analysis of differential gene expression revealed 44,335 contigs, and 662 differentially expressed genes between the stress and normally watered control group. Gene expression was specific to the different time points, and only five genes were significantly differentially expressed between the stress and control group on all five sampling days. GO term enrichment showed that mostly genes involved in lipid- and homeostasis-related processes were upregulated, whereas genes involved in oxidative stress response were downregulated in the stressed seedlings. This study gives first insights into the genomic drought stress response of European beech, and provides new genetic resources for adaptation research in this species.

The Crystal Structure of a Maxi/Mini-Ferritin Chimera Reveals Guiding Principles for the Assembly of Protein Cages

Energy Technology Data Exchange (ETDEWEB)

Cornell, Thomas A. [Department; Division; Srivastava, Yogesh [Genome; Jauch, Ralf [Genome Institute of Singapore, Singapore; Genome; Fan, Rongli [Division; Orner, Brendan P. [Department; Division

2017-07-19

Cage proteins assemble into nanoscale structures with large central cavities. They play roles, including those as virus capsids and chaperones, and have been applied to drug delivery and nanomaterials. Furthermore, protein cages have been used as model systems to understand and design protein quaternary structure. Ferritins are ubiquitous protein cages that manage iron homeostasis and oxidative damage. Two ferritin subfamilies have strongly similar tertiary structure yet distinct quaternary structure: maxi-ferritins normally assemble into 24-meric, octahedral cages with C-terminal E-helices centered around 4-fold symmetry axes, and mini-ferritins are 12-meric, tetrahedral cages with 3-fold axes defined by C-termini lacking E-domains. To understand the role E-domains play in ferritin quaternary structure, we previously designed a chimera of a maxi-ferritin E-domain fused to the C-terminus of a mini-ferritin. The chimera is a 12-mer cage midway in size between those of the maxi- and mini-ferritin. The research described herein sets out to understand (a) whether the increase in size over a typical mini-ferritin is due to a frozen state where the E-domain is flipped out of the cage and (b) whether the symmetrical preference of the E-domain in the maxi-ferritin (4-fold axis) overrules the C-terminal preference in the mini-ferritin (3-fold axis). With a 1.99 Å resolution crystal structure, we determined that the chimera assembles into a tetrahedral cage that can be nearly superimposed with the parent mini-ferritin, and that the E-domains are flipped external to the cage at the 3-fold symmetry axes.

Folding and Function of Proteorhodopsins in Photoenergy Transducing Membranes

Energy Technology Data Exchange (ETDEWEB)

Spudich, John L. [University of Texas Medical School, Houston, TX (United States). Health Science Center, Dept. of Biochemistry and Molecular Biology

2012-08-10

The overall research objectives are to develop proteorhodopsin (PR) proteins as a model system for α-helical membrane protein insertion and folding, and to advance understanding of the diversity and mechanisms of PRs, a large family of photoenergy transducers (~4000 identified) abundant in the world’s oceans. Specific aims are: (1) To develop a high-efficiency genetic selection procedure for light-driven proton-pumping in E. coli cells. Such a procedure would provide a positive selection method for proper folding and function of PRs in the E. coli membrane. (2) Characterize flash-induced absorption changes and photocurrents in PR variants in organisms from various environments, and their expression level and function when expressed in E. coli. Subaims are to: (a) elucidate the relationship of the transport mechanism to mechanisms of other microbial rhodopsins, some of which like PRs function as ion transporters and some of which use light energy to activate signaling pathways (sensory rhodopsins); and (b) identify important residues and chemical events in light-driven proton transport by PRs. In addition to their importance to the energy of the biosphere PRs have attracted interest for their potential for use in making photoenergy-transducing membranes for bioengineering applications.

Dysregulated RNA-Induced Silencing Complex (RISC) Assembly within CNS Corresponds with Abnormal miRNA Expression during Autoimmune Demyelination.

Science.gov (United States)

Lewkowicz, Przemysław; Cwiklińska, Hanna; Mycko, Marcin P; Cichalewska, Maria; Domowicz, Małgorzata; Lewkowicz, Natalia; Jurewicz, Anna; Selmaj, Krzysztof W

2015-05-13

MicroRNAs (miRNAs) associate with Argonaute (Ago), GW182, and FXR1 proteins to form RNA-induced silencing complexes (RISCs). RISCs represent a critical checkpoint in the regulation and bioavailability of miRNAs. Recent studies have revealed dysregulation of miRNAs in multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE); however, the function of RISCs in EAE and MS is largely unknown. Here, we examined the expression of Ago, GW182, and FXR1 in CNS tissue, oligodendrocytes (OLs), brain-infiltrating T lymphocytes, and CD3(+)splenocytes (SCs) of EAE mic, and found that global RISC protein levels were significantly dysregulated. Specifically, Ago2 and FXR1 levels were decreased in OLs and brain-infiltrating T cells in EAE mice. Accordingly, assembly of Ago2/GW182/FXR1 complexes in EAE brain tissues was disrupted, as confirmed by immunoprecipitation experiments. In parallel with alterations in RISC complex content in OLs, we found downregulation of miRNAs essential for differentiation and survival of OLs and myelin synthesis. In brain-infiltrating T lymphocytes, aberrant RISC formation contributed to miRNA-dependent proinflammatory helper T-cell polarization. In CD3(+) SCs, we found increased expression of both Ago2 and FXR1 in EAE compared with nonimmunized mice. Therefore, our results demonstrate a gradient in expression of miRNA between primary activated T cells in the periphery and polarized CNS-infiltrating T cells. These results suggest that, in polarized autoreactive effector T cells, miRNA synthesis is inhibited in response to dysregulated RISC assembly, allowing these cells to maintain a highly specific proinflammatory program. Therefore, our findings may provide a mechanism that leads to miRNA dysregulation in EAE/MS. Copyright © 2015 the authors 0270-6474/15/357521-17$15.00/0.

Relative crystallinity of plant biomass: studies on assembly, adaptation and acclimation.

Directory of Open Access Journals (Sweden)

Darby Harris

Full Text Available Plant biomechanical design is central to cell shape, morphogenesis, reproductive performance and protection against environmental and mechanical stress. The cell wall forms the central load bearing support structure for plant design, yet a mechanistic understanding of its synthesis is incomplete. A key tool for studying the structure of cellulose polymorphs has been x-ray diffraction and fourier transform infrared spectroscopy (FTIR. Relative crystallinity index (RCI is based on the x-ray diffraction characteristics of two signature peaks and we used this technique to probe plant assembly, adaptation and acclimation. Confocal microscopy was used to visualize the dynamics of cellulose synthase in transgenic Arabidopsis plants expressing a homozygous YFP::CESA6. Assembly: RCI values for stems and roots were indistinguishable but leaves had 23.4 and 21.6% lower RCI than stems and roots respectively. Adaptation: over 3-fold variability in RCI was apparent in leaves from 35 plant species spanning Ordovician to Cretaceous periods. Within this study, RCI correlated positively with leaf geometric constraints and with mass per unit area, suggestive of allometry. Acclimation: biomass crystallinity was found to decrease under conditions of thigmomorphogenesis in Arabidopsis. Further, in etiolated pea hypocotyls, RCI values also decreased compared to plants that were grown in light, consistent with alterations in FTIR cellulose fingerprint peaks and live cell imaging experiments revealing rapid orientation of the YFP::cellulose synthase-6 array in response to light. Herein, results and technical challenges associated with the structure of the cell wall that gives rise to sample crystallinity are presented and examined with respect to adaptation, acclimation and assembly in ecosystem-level processes.

Therapeutic potential of gel-based injectables for vocal fold regeneration

Science.gov (United States)

Bartlett, Rebecca S.; Thibeault, Susan L.; Prestwich, Glenn D.

2012-01-01

Vocal folds are anatomically and biomechanically unique, thus complicating the design and implementation of tissue engineering strategies for repair and regeneration. Integration of an enhanced understanding of tissue biomechanics, wound healing dynamics and innovative gel-based therapeutics has generated enthusiasm for the notion that an efficacious treatment for vocal fold scarring could be clinically attainable within several years. Fibroblast phenotype and gene expression are mediated by the three-dimensional mechanical and chemical microenvironment at an injury site. Thus, therapeutic approaches need to coordinate spatial and temporal aspects of the wound healing response in an injured vocal tissue to achieve an optimal clinical outcome. Successful gel-based injectables for vocal fold scarring will require a keen understanding of how the native inflammatory response sets into motion the later extracellular matrix remodeling, which in turn will determine the ultimate biomechanical properties of the tissue. We present an overview of the challenges associated with this translation as well as the proposed gel-based injectable solutions. PMID:22456756

Therapeutic potential of gel-based injectables for vocal fold regeneration

International Nuclear Information System (INIS)

Bartlett, Rebecca S; Thibeault, Susan L; Prestwich, Glenn D

2012-01-01

Vocal folds are anatomically and biomechanically unique, thus complicating the design and implementation of tissue engineering strategies for repair and regeneration. Integration of an enhanced understanding of tissue biomechanics, wound healing dynamics and innovative gel-based therapeutics has generated enthusiasm for the notion that an efficacious treatment for vocal fold scarring could be clinically attainable within several years. Fibroblast phenotype and gene expression are mediated by the three-dimensional mechanical and chemical microenvironment at an injury site. Thus, therapeutic approaches need to coordinate spatial and temporal aspects of the wound healing response in an injured vocal tissue to achieve an optimal clinical outcome. Successful gel-based injectables for vocal fold scarring will require a keen understanding of how the native inflammatory response sets into motion the later extracellular matrix remodeling, which in turn will determine the ultimate biomechanical properties of the tissue. We present an overview of the challenges associated with this translation as well as the proposed gel-based injectable solutions. (paper)

Steady-state structural fluctuation is a predictor of the necessity of pausing-mediated co-translational folding for small proteins.

Science.gov (United States)

Huang, Wenxi; Liu, Wanting; Jin, Jingjie; Xiao, Qilan; Lu, Ruibin; Chen, Wei; Xiong, Sheng; Zhang, Gong

2018-03-25

Translational pausing coordinates protein synthesis and co-translational folding. It is a common factor that facilitates the correct folding of large, multi-domain proteins. For small proteins, pausing sites rarely occurs in the gene body, and the 3'-end pausing sites are only essential for the folding of a fraction of proteins. The determinant of the necessity of the pausings remains obscure. In this study, we demonstrated that the steady-state structural fluctuation is a predictor of the necessity of pausing-mediated co-translational folding for small proteins. Validated by experiments with 5 model proteins, we found that the rigid protein structures do not, while the flexible structures do need 3'-end pausings to fold correctly. Therefore, rational optimization of translational pausing can improve soluble expression of small proteins with flexible structures, but not the rigid ones. The rigidity of the structure can be quantitatively estimated in silico using molecular dynamic simulation. Nevertheless, we also found that the translational pausing optimization increases the fitness of the expression host, and thus benefits the recombinant protein production, independent from the soluble expression. These results shed light on the structural basis of the translational pausing and provided a practical tool for industrial protein fermentation. Copyright © 2017. Published by Elsevier Inc.

One-step self-assembled nanomicelles for improving the oral bioavailability of nimodipine.

Science.gov (United States)

Luo, Jing-Wen; Zhang, Zhi-Rong; Gong, Tao; Fu, Yao

2016-01-01

Our study aimed to develop a self-assembled nanomicelle for oral administration of nimodipine (NIM) with poor water solubility. Using Solutol(®) HS15, the NIM-loaded self-assembled nanomicelles displayed a near-spherical morphology with a narrow size distribution of 12.57 ± 0.21 nm (polydispersity index =0.071 ± 0.011). Compared with Nimotop(®) (NIM tablets), the intestinal absorption of NIM from NIM nanomicelle in rats was improved by 3.13- and 2.25-fold in duodenum and jejunum at 1 hour after oral administration. The cellular transport of NIM nanomicelle in Caco-2 cell monolayers was significantly enhanced compared to that of Nimotop(®). Regarding the transport pathways, clathrin, lipid raft/caveolae, and macropinocytosis mediated the cell uptake of NIM nanomicelles, while P-glycoprotein and endoplasmic reticulum/Golgi complex (ER/Golgi) pathways were involved in exocytosis. Pharmacokinetic studies in our research laboratory have showed that the area under the plasma concentration-time curve (AUC0-∞) of NIM nanomicelles was 3.72-fold that of Nimotop(®) via oral administration in rats. Moreover, the NIM concentration in the brain from NIM nanomicelles was dramatically improved. Therefore, Solutol(®) HS15-based self-assembled nanomicelles represent a promising delivery system to enhance the oral bioavailability of NIM.

The Risk of Vocal Fold Atrophy after Serial Corticosteroid Injections of the Vocal Fold.

Science.gov (United States)

Shi, Lucy L; Giraldez-Rodriguez, Laureano A; Johns, Michael M

2016-11-01

The aim of this study was to illustrate the risk of vocal fold atrophy in patients who receive serial subepithelial steroid injections for vocal fold scar. This study is a retrospective case report of two patients who underwent a series of weekly subepithelial infusions of 10 mg/mL dexamethasone for benign vocal fold lesion. Shortly after the procedures, both patients developed a weak and breathy voice. The first patient was a 53-year-old man with radiation-induced vocal fold stiffness. Six injections were performed unilaterally, and 1 week later, he developed unilateral vocal fold atrophy with new glottal insufficiency. The second patient was a 67-year-old woman with severe vocal fold inflammation related to laryngitis and calcinosis, Raynaud's phenomenon, esophagean dysmotility, sclerodactyly, and telangiectasia (CREST) syndrome. Five injections were performed bilaterally, and 1 week later, she developed bilateral vocal fold atrophy with a large midline glottal gap during phonation. In both cases, the steroid-induced vocal atrophy resolved spontaneously after 4 months. Serial subepithelial steroid infusions of the vocal folds, although safe in the majority of patients, carry the risk of causing temporary vocal fold atrophy when given at short intervals. Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Stoichiometric Assembly of the Cellulosome Generates Maximum Synergy for the Degradation of Crystalline Cellulose, as Revealed by In Vitro Reconstitution of the Clostridium thermocellum Cellulosome.

Science.gov (United States)

Hirano, Katsuaki; Nihei, Satoshi; Hasegawa, Hiroki; Haruki, Mitsuru; Hirano, Nobutaka

2015-07-01

The cellulosome is a supramolecular multienzyme complex formed by species-specific interactions between the cohesin modules of scaffoldin proteins and the dockerin modules of a wide variety of polysaccharide-degrading enzymes. Cellulosomal enzymes bound to the scaffoldin protein act synergistically to degrade crystalline cellulose. However, there have been few attempts to reconstitute intact cellulosomes due to the difficulty of heterologously expressing full-length scaffoldin proteins. We describe the synthesis of a full-length scaffoldin protein containing nine cohesin modules, CipA; its deletion derivative containing two cohesin modules, ΔCipA; and three major cellulosomal cellulases, Cel48S, Cel8A, and Cel9K, of the Clostridium thermocellum cellulosome. The proteins were synthesized using a wheat germ cell-free protein synthesis system, and the purified proteins were used to reconstitute cellulosomes. Analysis of the cellulosome assembly using size exclusion chromatography suggested that the dockerin module of the enzymes stoichiometrically bound to the cohesin modules of the scaffoldin protein. The activity profile of the reconstituted cellulosomes indicated that cellulosomes assembled at a CipA/enzyme molar ratio of 1/9 (cohesin/dockerin = 1/1) and showed maximum synergy (4-fold synergy) for the degradation of crystalline substrate and ∼2.4-fold-higher synergy for its degradation than minicellulosomes assembled at a ΔCipA/enzyme molar ratio of 1/2 (cohesin/dockerin = 1/1). These results suggest that the binding of more enzyme molecules on a single scaffoldin protein results in higher synergy for the degradation of crystalline cellulose and that the stoichiometric assembly of the cellulosome, without excess or insufficient enzyme, is crucial for generating maximum synergy for the degradation of crystalline cellulose. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Human Polycomb group EED protein negatively affects HIV-1 assembly and release

Directory of Open Access Journals (Sweden)

Darlix Jean-Luc

2007-06-01

Full Text Available Abstract Background The human EED protein, a member of the superfamily of Polycomb group (PcG proteins with WD-40 repeats, has been found to interact with three HIV-1 components, namely the structural Gag matrix protein (MA, the integrase enzyme (IN and the Nef protein. The aim of the present study was to analyze the possible biological role of EED in HIV-1 replication, using the HIV-1-based vector HIV-Luc and EED protein expressed by DNA transfection of 293T cells. Results During the early phase of HIV-1 infection, a slight negative effect on virus infectivity occurred in EED-expressing cells, which appeared to be dependent on EED-MA interaction. At late times post infection, EED caused an important reduction of virus production, from 20- to 25-fold as determined by CAp24 immunoassay, to 10- to 80-fold based on genomic RNA levels, and this decrease was not due to a reduction of Gag protein synthesis. Coexpression of WTNef, or the non-N-myristoylated mutant NefG2A, restored virus yields to levels obtained in the absence of exogenous EED protein. This effect was not observed with mutant NefΔ57 mimicking the Nef core, or with the lipid raft-retargeted fusion protein LAT-Nef. LATAA-Nef, a mutant defective in the lipid raft addressing function, had the same anti-EED effect as WTNef. Cell fractionation and confocal imaging showed that, in the absence of Nef, EED mainly localized in membrane domains different from the lipid rafts. Upon co-expression with WTNef, NefG2A or LATAA-Nef, but not with NefΔ57 or LAT-Nef, EED was found to relocate into an insoluble fraction along with Nef protein. Electron microscopy of HIV-Luc producer cells overexpressing EED showed significant less virus budding at the cell surface compared to control cells, and ectopic assembly and clustering of nuclear pore complexes within the cytoplasm. Conclusion Our data suggested that EED exerted an antiviral activity at the late stage of HIV-1 replication, which included genomic

NoFold: RNA structure clustering without folding or alignment.

Science.gov (United States)

Middleton, Sarah A; Kim, Junhyong

2014-11-01

Structures that recur across multiple different transcripts, called structure motifs, often perform a similar function-for example, recruiting a specific RNA-binding protein that then regulates translation, splicing, or subcellular localization. Identifying common motifs between coregulated transcripts may therefore yield significant insight into their binding partners and mechanism of regulation. However, as most methods for clustering structures are based on folding individual sequences or doing many pairwise alignments, this results in a tradeoff between speed and accuracy that can be problematic for large-scale data sets. Here we describe a novel method for comparing and characterizing RNA secondary structures that does not require folding or pairwise alignment of the input sequences. Our method uses the idea of constructing a distance function between two objects by their respective distances to a collection of empirical examples or models, which in our case consists of 1973 Rfam family covariance models. Using this as a basis for measuring structural similarity, we developed a clustering pipeline called NoFold to automatically identify and annotate structure motifs within large sequence data sets. We demonstrate that NoFold can simultaneously identify multiple structure motifs with an average sensitivity of 0.80 and precision of 0.98 and generally exceeds the performance of existing methods. We also perform a cross-validation analysis of the entire set of Rfam families, achieving an average sensitivity of 0.57. We apply NoFold to identify motifs enriched in dendritically localized transcripts and report 213 enriched motifs, including both known and novel structures. © 2014 Middleton and Kim; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

Simple Evaluation of Load-Carrying Capacity of Multi-Span Folding Bridges based on Floating Supports

Directory of Open Access Journals (Sweden)

Jan Marszałek

2014-12-01

Full Text Available [b]Abstract[/b]. The papers covers simple evaluation of load-carrying capacity of multi-span folding bridges based on floating supports. Combined bridges built in this approach, could be used as a temporary crossing. The methodology of this evaluation is shown graphically on the basis of designed nomograms for two existing bridge structures i.e. MS-54 and DMS-65, mounted on rigid and floating supports. These nomograms facilitate the simple and fast determination of the impact of changing fixed support into floating support with different bridge length spans on the carrying capacity of the bridge. The paper also presents the influence of long-term use (enlarging the mounting backlash in the joints of these structures on the carrying capacity of the bridge.[b]Keywords[/b]: building, folding bridges, nomograms, assembly clearances

Orthology Guided Assembly in highly heterozygous crops

DEFF Research Database (Denmark)

Ruttink, Tom; Sterck, Lieven; Rohde, Antje

2013-01-01

to outbreeding crop species hamper De Bruijn Graph-based de novo assembly algorithms, causing transcript fragmentation and the redundant assembly of allelic contigs. If multiple genotypes are sequenced to study genetic diversity, primary de novo assembly is best performed per genotype to limit the level......Despite current advances in next-generation sequencing data analysis procedures, de novo assembly of a reference sequence required for SNP discovery and expression analysis is still a major challenge in genetically uncharacterized, highly heterozygous species. High levels of polymorphism inherent...... of polymorphism and avoid transcript fragmentation. Here, we propose an Orthology Guided Assembly procedure that first uses sequence similarity (tBLASTn) to proteins of a model species to select allelic and fragmented contigs from all genotypes and then performs CAP3 clustering on a gene-by-gene basis. Thus, we...

Glycoprotein folding and quality-control mechanisms in protein-folding diseases

Directory of Open Access Journals (Sweden)

Sean P. Ferris

2014-03-01

Full Text Available Biosynthesis of proteins – from translation to folding to export – encompasses a complex set of events that are exquisitely regulated and scrutinized to ensure the functional quality of the end products. Cells have evolved to capitalize on multiple post-translational modifications in addition to primary structure to indicate the folding status of nascent polypeptides to the chaperones and other proteins that assist in their folding and export. These modifications can also, in the case of irreversibly misfolded candidates, signal the need for dislocation and degradation. The current Review focuses on the glycoprotein quality-control (GQC system that utilizes protein N-glycosylation and N-glycan trimming to direct nascent glycopolypeptides through the folding, export and dislocation pathways in the endoplasmic reticulum (ER. A diverse set of pathological conditions rooted in defective as well as over-vigilant ER quality-control systems have been identified, underlining its importance in human health and disease. We describe the GQC pathways and highlight disease and animal models that have been instrumental in clarifying our current understanding of these processes.

The assembly of MreB, a prokaryotic homolog of actin.

Science.gov (United States)

Esue, Osigwe; Cordero, Maria; Wirtz, Denis; Tseng, Yiider

2005-01-28

MreB, a major component of the bacterial cytoskeleton, exhibits high structural homology to its eukaryotic counterpart actin. Live cell microscopy studies suggest that MreB molecules organize into large filamentous spirals that support the cell membrane and play a key shape-determining function. However, the basic properties of MreB filament assembly remain unknown. Here, we studied the assembly of Thermotoga maritima MreB triggered by ATP in vitro and compared it to the well-studied assembly of actin. These studies show that MreB filament ultrastructure and polymerization depend crucially on temperature as well as the ions present on solution. At the optimal growth temperature of T. maritima, MreB assembly proceeded much faster than that of actin, without nucleation (or nucleation is highly favorable and fast) and with little or no contribution from filament end-to-end annealing. MreB exhibited rates of ATP hydrolysis and phosphate release similar to that of F-actin, however, with a critical concentration of approximately 3 nm, which is approximately 100-fold lower than that of actin. Furthermore, MreB assembled into filamentous bundles that have the ability to spontaneously form ring-like structures without auxiliary proteins. These findings suggest that despite high structural homology, MreB and actin display significantly different assembly properties.

Modulation of the maladaptive stress response to manage diseases of protein folding.

Directory of Open Access Journals (Sweden)

Daniela Martino Roth

2014-11-01

Full Text Available Diseases of protein folding arise because of the inability of an altered peptide sequence to properly engage protein homeostasis components that direct protein folding and function. To identify global principles of misfolding disease pathology we examined the impact of the local folding environment in alpha-1-antitrypsin deficiency (AATD, Niemann-Pick type C1 disease (NPC1, Alzheimer's disease (AD, and cystic fibrosis (CF. Using distinct models, including patient-derived cell lines and primary epithelium, mouse brain tissue, and Caenorhabditis elegans, we found that chronic expression of misfolded proteins not only triggers the sustained activation of the heat shock response (HSR pathway, but that this sustained activation is maladaptive. In diseased cells, maladaptation alters protein structure-function relationships, impacts protein folding in the cytosol, and further exacerbates the disease state. We show that down-regulation of this maladaptive stress response (MSR, through silencing of HSF1, the master regulator of the HSR, restores cellular protein folding and improves the disease phenotype. We propose that restoration of a more physiological proteostatic environment will strongly impact the management and progression of loss-of-function and gain-of-toxic-function phenotypes common in human disease.

Failure to synthesize the CD3-gamma chain. Consequences for T cell antigen receptor assembly, processing, and expression

DEFF Research Database (Denmark)

Geisler, C

1992-01-01

surface expression of the Ti/CD3 complex. Transfection of the wild-type CD3-gamma gene into JGN reconstituted expression of functional Ti/CD3 complexes, and analysis of T cell lines producing different amounts of CD3-gamma indicated that CD3-gamma and CD3-delta competed for the binding to CD3-epsilon.......The TCR consists of the Ti alpha beta heterodimer and the associated CD3 chains, CD3 gamma delta epsilon zeta 2 or zeta eta. The structural relationships between the subunits of the Ti/CD3 complex are still not fully understood. To explore the roles of the individual CD3 chains for the assembly......, intracellular processing, and expression of the TCR, mutants of the T cell line Jurkat were isolated. One variant, JGN, was found to produce all the Ti/CD3 components with the exception of CD3-gamma. The results indicate that: 1) the tetrameric form (Ti alpha beta-CD3 delta epsilon) of the Ti/CD3 complex...

Folding very short peptides using molecular dynamics.

Directory of Open Access Journals (Sweden)

Bosco K Ho

2006-04-01

Full Text Available Peptides often have conformational preferences. We simulated 133 peptide 8-mer fragments from six different proteins, sampled by replica-exchange molecular dynamics using Amber7 with a GB/SA (generalized-Born/solvent-accessible electrostatic approximation to water implicit solvent. We found that 85 of the peptides have no preferred structure, while 48 of them converge to a preferred structure. In 85% of the converged cases (41 peptides, the structures found by the simulations bear some resemblance to their native structures, based on a coarse-grained backbone description. In particular, all seven of the beta hairpins in the native structures contain a fragment in the turn that is highly structured. In the eight cases where the bioinformatics-based I-sites library picks out native-like structures, the present simulations are largely in agreement. Such physics-based modeling may be useful for identifying early nuclei in folding kinetics and for assisting in protein-structure prediction methods that utilize the assembly of peptide fragments.

Folding of multidomain proteins: biophysical consequences of tethering even in apparently independent folding.

Science.gov (United States)

Arviv, Oshrit; Levy, Yaakov

2012-12-01

Most eukaryotic and a substantial fraction of prokaryotic proteins are composed of more than one domain. The tethering of these evolutionary, structural, and functional units raises, among others, questions regarding the folding process of conjugated domains. Studying the folding of multidomain proteins in silico enables one to identify and isolate the tethering-induced biophysical determinants that govern crosstalks generated between neighboring domains. For this purpose, we carried out coarse-grained and atomistic molecular dynamics simulations of two two-domain constructs from the immunoglobulin-like β-sandwich fold. Each of these was experimentally shown to behave as the "sum of its parts," that is, the thermodynamic and kinetic folding behavior of the constituent domains of these constructs seems to occur independently, with the folding of each domain uncoupled from the folding of its partner in the two-domain construct. We show that the properties of the individual domains can be significantly affected by conjugation to another domain. The tethering may be accompanied by stabilizing as well as destabilizing factors whose magnitude depends on the size of the interface, the length, and the flexibility of the linker, and the relative stability of the domains. Accordingly, the folding of a multidomain protein should not be viewed as the sum of the folding patterns of each of its parts, but rather, it involves abrogating several effects that lead to this outcome. An imbalance between these effects may result in either stabilization or destabilization owing to the tethering. Copyright © 2012 Wiley Periodicals, Inc.

Improving Energy Efficiency for the Vehicle Assembly Industry: A Discrete Event Simulation Approach

Science.gov (United States)

Oumer, Abduaziz; Mekbib Atnaw, Samson; Kie Cheng, Jack; Singh, Lakveer

2016-11-01

This paper presented a Discrete Event Simulation (DES) model for investigating and improving energy efficiency in vehicle assembly line. The car manufacturing industry is one of the highest energy consuming industries. Using Rockwell Arena DES package; a detailed model was constructed for an actual vehicle assembly plant. The sources of energy considered in this research are electricity and fuel; which are the two main types of energy sources used in a typical vehicle assembly plant. The model depicts the performance measurement for process- specific energy measures of painting, welding, and assembling processes. Sound energy efficiency model within this industry has two-fold advantage: reducing CO2 emission and cost reduction associated with fuel and electricity consumption. The paper starts with an overview of challenges in energy consumption within the facilities of automotive assembly line and highlights the parameters for energy efficiency. The results of the simulation model indicated improvements for energy saving objectives and reduced costs.

Synovial folds in the knee joint

International Nuclear Information System (INIS)

Schaefer, H.

1987-01-01

Stimulated by arthroscopic insight into central abnormalities of the knee joint and by the large number of unexplained case of 'anterior knee pain', we have studied the synovia in more than 2000 contrast examinations of the joint. Surprisingly, and contrary to the views expressed in the literature, the clinically significant plica parapatellaris medialis was seen as frequently during pneumo-arthrography as during more complex procedures. Abnormalities in the synovial fold emerged as a discreet disease identified as the 'medial shelf syndrome' and should be included in the differential diagnosis of causes of pain round the lower end of the femur and patella. (orig.) [de

Spindle assembly checkpoint protein expression correlates with cellular proliferation and shorter time to recurrence in ovarian cancer.

LENUS (Irish Health Repository)

McGrogan, Barbara

2014-07-01

Ovarian carcinoma (OC) is the most lethal of the gynecological malignancies, often presenting at an advanced stage. Treatment is hampered by high levels of drug resistance. The taxanes are microtubule stabilizing agents, used as first-line agents in the treatment of OC that exert their apoptotic effects through the spindle assembly checkpoint. BUB1-related protein kinase (BUBR1) and mitotic arrest deficient 2 (MAD2), essential spindle assembly checkpoint components, play a key role in response to taxanes. BUBR1, MAD2, and Ki-67 were assessed on an OC tissue microarray platform representing 72 OC tumors of varying histologic subtypes. Sixty-one of these patients received paclitaxel and platinum agents combined; 11 received platinum alone. Overall survival was available for all 72 patients, whereas recurrence-free survival (RFS) was available for 66 patients. Increased BUBR1 expression was seen in serous carcinomas, compared with other histologies (P = .03). Increased BUBR1 was significantly associated with tumors of advanced stage (P = .05). Increased MAD2 and BUBR1 expression also correlated with increased cellular proliferation (P < .0002 and P = .02, respectively). Reduced MAD2 nuclear intensity was associated with a shorter RFS (P = .03), in ovarian tumors of differing histologic subtype (n = 66). In this subgroup, for those women who received paclitaxel and platinum agents combined (n = 57), reduced MAD2 intensity also identified women with a shorter RFS (P < .007). For the entire cohort of patients, irrespective of histologic subtype or treatment, MAD2 nuclear intensity retained independent significance in a multivariate model, with tumors showing reduced nuclear MAD2 intensity identifying patients with a poorer RFS (P = .05).

Structural Polymorphism in a Self-Assembled Tri-Aromatic Peptide System.

Science.gov (United States)

Brown, Noam; Lei, Jiangtao; Zhan, Chendi; Shimon, Linda J W; Adler-Abramovich, Lihi; Wei, Guanghong; Gazit, Ehud

2018-04-24

Self-assembly is a process of key importance in natural systems and in nanotechnology. Peptides are attractive building blocks due to their relative facile synthesis, biocompatibility, and other unique properties. Diphenylalanine (FF) and its derivatives are known to form nanostructures of various architectures and interesting and varied characteristics. The larger triphenylalanine peptide (FFF) was found to self-assemble as efficiently as FF, forming related but distinct architectures of plate-like and spherical nanostructures. Here, to understand the effect of triaromatic systems on the self-assembly process, we examined carboxybenzyl-protected diphenylalanine (z-FF) as a minimal model for such an arrangement. We explored different self-assembly conditions by changing solvent compositions and peptide concentrations, generating a phase diagram for the assemblies. We discovered that z-FF can form a variety of structures, including nanowires, fibers, nanospheres, and nanotoroids, the latter were previously observed only in considerably larger or co-assembly systems. Secondary structure analysis revealed that all assemblies possessed a β-sheet conformation. Additionally, in solvent combinations with high water ratios, z-FF formed rigid and self-healing hydrogels. X-ray crystallography revealed a "wishbone" structure, in which z-FF dimers are linked by hydrogen bonds mediated by methanol molecules, with a 2-fold screw symmetry along the c-axis. All-atom molecular dynamics (MD) simulations revealed conformations similar to the crystal structure. Coarse-grained MD simulated the assembly of the peptide into either fibers or spheres in different solvent systems, consistent with the experimental results. This work thus expands the building block library for the fabrication of nanostructures by peptide self-assembly.

Expression Pattern of the Alpha-Kafirin Promoter Coupled with a Signal Peptide from Sorghum bicolor L. Moench

Directory of Open Access Journals (Sweden)

Norazlina Ahmad

2012-01-01

Full Text Available Regulatory sequences with endosperm specificity are essential for foreign gene expression in the desired tissue for both grain quality improvement and molecular pharming. In this study, promoters of seed storage α-kafirin genes coupled with signal sequence (ss were isolated from Sorghum bicolor L. Moench genomic DNA by PCR. The α-kafirin promoter (α-kaf contains endosperm specificity-determining motifs, prolamin-box, the O2-box 1, CATC, and TATA boxes required for α-kafirin gene expression in sorghum seeds. The constructs pMB-Ubi-gfp and pMB-kaf-gfp were microprojectile bombarded into various sorghum and sweet corn explants. GFP expression was detected on all explants using the Ubi promoter but only in seeds for the α-kaf promoter. This shows that the α-kaf promoter isolated was functional and demonstrated seed-specific GFP expression. The constructs pMB-Ubi-ss-gfp and pMB-kaf-ss-gfp were also bombarded into the same explants. Detection of GFP expression showed that the signal peptide (SP::GFP fusion can assemble and fold properly, preserving the fluorescent properties of GFP.

Constitutive Cdk2 activity promotes aneuploidy while altering the spindle assembly and tetraploidy checkpoints

DEFF Research Database (Denmark)

Jahn, Stephan C; Corsino, Patrick E; Davis, Bradley J

2013-01-01

instability. Expression of these complexes in the MCF10A cell line leads to retinoblastoma protein (Rb) hyperphosphorylation, a subsequent increase in proliferation rate, and increased expression of the spindle assembly checkpoint protein Mad2. This results in a strengthening of the spindle assembly...

Histological Effect of Basic Fibroblast Growth Factor on Chronic Vocal Fold Scarring in a Rat Model.

Science.gov (United States)

Tateya, Ichiro; Tateya, Tomoko; Sohn, Jin-Ho; Bless, Diane M

2016-03-01

Vocal fold scarring is one of the most challenging laryngeal disorders to treat and there are currently no consistently effective treatments available. Our previous studies have shown the therapeutic potential of basic fibroblast growth factor (bFGF) for vocal fold scarring. However, the histological effects of bFGF on scarred vocal fold have not been elucidated. The aim of this study was to examine the histological effects of bFGF on chronic vocal fold scarring. Sprague-Dawley rats were divided into phosphate buffered saline (sham) and bFGF groups. Unilateral vocal fold stripping was performed and the drug was injected into the scarred vocal fold for each group 2 months postoperatively. Injections were performed weekly for 4 weeks. Two months after the last injection, larynges were harvested and histologically analyzed. A significant increase of hyaluronic acid was observed in the vocal fold of the bFGF group compared with that of the sham group. However, there was no remarkable change in collagen expression nor in vocal fold contraction. Significant increase of hyaluronic acid by local bFGF injection was thought to contribute to the therapeutic effects on chronic vocal fold scarring.

3D Visualization of Sheath Folds in Roman Marble from Ephesus, Turkey

Science.gov (United States)

Wex, Sebastian; Passchier, Cornelis W.; de Kemp, Eric A.; Ilhan, Sinan

2013-04-01

Excavation of a palatial 2nd century AD house (Terrace House Two) in the ancient city of Ephesus, Turkey in the 1970s produced 10.313 pieces of colored, folded marble which belonged to 54 marble plates of 1.6 cm thickness that originally covered the walls of the banquet hall of the house. The marble plates were completely reassembled and restored by a team of workers over the last 6 years. The plates were recognized as having been sawn from two separate large blocks of "Cipollino verde", a green mylonitized marble from Karystos on the Island of Euboea, Greece. After restoration, it became clear that all slabs had been placed on the wall in approximately the sequence in which they had been cut off by a Roman stone saw. As a result, the marble plates give a full 3D insight in the folded internal structure of 1m3 block of mylonite. The restoration of the slabs was recognized as a first, unique opportunity for detailed reconstruction of the 3D geometry of m-scale folds in mylonitized marble. Photographs were taken of each slab and used to reconstruct their exact arrangement within the originally quarried blocks. Outlines of layers were digitized and a full 3D reconstruction of the internal structure of the block was created using ArcMap and GOCAD. Fold structures in the block include curtain folds and multilayered sheath folds. Several different layers showing these structures were digitized on the photographs of the slab surfaces and virtually mounted back together within the model of the marble block. Due to the serial sectioning into slabs, with cm-scale spacing, the visualization of the 3D geometry of sheath folds was accomplished with a resolution better than 4 cm. Final assembled 3D images reveal how sheath folds emerge from continuous layers and show their overall consistency as well as a constant hinge line orientation of the fold structures. Observations suggest that a single deformation phase was responsible for the evolution of "Cipollino verde" structures

Comparison of de novo assembly statistics of Cucumis sativus L.

Science.gov (United States)

Wojcieszek, Michał; Kuśmirek, Wiktor; Pawełkowicz, Magdalena; PlÄ der, Wojciech; Nowak, Robert M.

2017-08-01

Genome sequencing is the core of genomic research. With the development of NGS and lowering the cost of procedure there is another tight gap - genome assembly. Developing the proper tool for this task is essential as quality of genome has important impact on further research. Here we present comparison of several de Bruijn assemblers tested on C. sativus genomic reads. The assessment shows that newly developed software - dnaasm provides better results in terms of quantity and quality. The number of generated sequences is lower by 5 - 33% with even two fold higher N50. Quality check showed reliable results were generated by dnaasm. This provides us with very strong base for future genomic analysis.

Co-Transcriptional Folding and Regulation Mechanisms of Riboswitches

Directory of Open Access Journals (Sweden)

Sha Gong

2017-07-01

Full Text Available Riboswitches are genetic control elements within non-coding regions of mRNA. These self-regulatory elements have been found to sense a range of small metabolites, ions, and other physical signals to exert regulatory control of transcription, translation, and splicing. To date, more than a dozen riboswitch classes have been characterized that vary widely in size and secondary structure. Extensive experiments and theoretical studies have made great strides in understanding the general structures, genetic mechanisms, and regulatory activities of individual riboswitches. As the ligand-dependent co-transcriptional folding and unfolding dynamics of riboswitches are the key determinant of gene expression, it is important to investigate the thermodynamics and kinetics of riboswitches both in the presence and absence of metabolites under the transcription. This review will provide a brief summary of the studies about the regulation mechanisms of the pbuE, SMK, yitJ, and metF riboswitches based on the ligand-dependent co-transcriptional folding of the riboswitches.

Evaluation of Dying Vocal Fold Epithelial Cells by Ultrastructural Features and TUNEL Method

Science.gov (United States)

Novaleski, Carolyn K.; Mizuta, Masanobu; Rousseau, Bernard

2016-01-01

Cell death is a regulated mechanism of eliminating cells to maintain tissue homeostasis. This study described two methodological procedures for evaluating cell death in the epithelium of immobilized, approximated, and vibrated vocal folds from 12 New Zealand white breeder rabbits. The gold standard technique of transmission electron microscopy evaluated high-quality ultrastructural criteria of cell death and a common immunohistochemical marker, terminal deoxynucleotidyl transferase dUTP nick end labeling method, to confirm cell death signaling. Results revealed that ultrastructural characteristics of apoptotic cell death, specifically condensed chromatin and apoptotic bodies, were observed after vocal fold vibration and approximation. Although episodes of necrotic cell death were rare, few enlarged cell nuclei were present after vibration and approximation. The vocal fold expresses an immunohistochemical marker for apoptosis along the apical surface of the epithelium. This study provides a solid foundation for future investigations regarding the role of cell death in vocal fold health and disease. PMID:27537846

Ferritin Assembly in Enterocytes of Drosophila melanogaster

Directory of Open Access Journals (Sweden)

Abraham Rosas-Arellano

2016-02-01

Full Text Available Ferritins are protein nanocages that accumulate inside their cavity thousands of oxidized iron atoms bound to oxygen and phosphates. Both characteristic types of eukaryotic ferritin subunits are present in secreted ferritins from insects, but here dimers between Ferritin 1 Heavy Chain Homolog (Fer1HCH and Ferritin 2 Light Chain Homolog (Fer2LCH are further stabilized by disulfide-bridge in the 24-subunit complex. We addressed ferritin assembly and iron loading in vivo using novel transgenic strains of Drosophila melanogaster. We concentrated on the intestine, where the ferritin induction process can be controlled experimentally by dietary iron manipulation. We showed that the expression pattern of Fer2LCH-Gal4 lines recapitulated iron-dependent endogenous expression of the ferritin subunits and used these lines to drive expression from UAS-mCherry-Fer2LCH transgenes. We found that the Gal4-mediated induction of mCherry-Fer2LCH subunits was too slow to effectively introduce them into newly formed ferritin complexes. Endogenous Fer2LCH and Fer1HCH assembled and stored excess dietary iron, instead. In contrast, when flies were genetically manipulated to co-express Fer2LCH and mCherry-Fer2LCH simultaneously, both subunits were incorporated with Fer1HCH in iron-loaded ferritin complexes. Our study provides fresh evidence that, in insects, ferritin assembly and iron loading in vivo are tightly regulated.

Crystallization and preliminary X-ray analysis of tubulin-folding cofactor A from Arabidopsis thaliana

International Nuclear Information System (INIS)

Lu, Lu; Nan, Jie; Mi, Wei; Wei, Chun-Hong; Li, Lan-Fen; Li, Yi

2010-01-01

Tubulin-folding cofactor A from A. thaliana has been crystallized and preliminarily analyzed using X-ray diffraction. Tubulin-folding cofactor A (TFC A) is a molecular post-chaperonin that is involved in the β-tubulin-folding pathway. It has been identified in many organisms including yeasts, humans and plants. In this work, Arabidopsis thaliana TFC A was expressed in Escherichia coli and purified to homogeneity. After thrombin cleavage, a well diffracting crystal was obtained by the sitting-drop vapour-diffusion method at 289 K. The crystal diffracted to 1.6 Å resolution using synchrotron radiation and belonged to space group I4 1 , with unit-cell parameters a = 55.0, b = 55.0, c = 67.4 Å

Differential Expression of Adhesion-Related Proteins and MAPK Pathways Lead to Suitable Osteoblast Differentiation of Human Mesenchymal Stem Cells Subpopulations.

Science.gov (United States)

Leyva-Leyva, Margarita; López-Díaz, Annia; Barrera, Lourdes; Camacho-Morales, Alberto; Hernandez-Aguilar, Felipe; Carrillo-Casas, Erika M; Arriaga-Pizano, Lourdes; Calderón-Pérez, Jaime; García-Álvarez, Jorge; Orozco-Hoyuela, Gabriel; Piña-Barba, Cristina; Rojas-Martínez, Augusto; Romero-Díaz, Víktor; Lara-Arias, Jorge; Rivera-Bolaños, Nancy; López-Camarillo, César; Moncada-Saucedo, Nidia; Galván-De los Santos, Alejandra; Meza-Urzúa, Fátima; Villarreal-Gómez, Luis; Fuentes-Mera, Lizeth

2015-11-01

Cellular adhesion enables communication between cells and their environment. Adhesion can be achieved throughout focal adhesions and its components influence osteoblast differentiation of human mesenchymal stem cells (hMSCs). Because cell adhesion and osteoblast differentiation are closely related, this article aimed to analyze the expression profiles of adhesion-related proteins during osteoblastic differentiation of two hMSCs subpopulations (CD105(+) and CD105(-)) and propose a strategy for assembling bone grafts based on its adhesion ability. In vitro experiments of osteogenic differentiation in CD105(-) cells showed superior adhesion efficiency and 2-fold increase of α-actinin expression compared with CD105(+) cells at the maturation stage. Interestingly, levels of activated β1-integrin increased in CD105(-) cells during the process. Additionally, the CD105(-) subpopulation showed 3-fold increase of phosphorylated FAK(Y397) compared to CD105(+) cells. Results also indicate that ERK1/2 was activated during CD105(-) bone differentiation and participation of mitogen-activated protein kinase (MAPK)-p38 in CD105(+) differentiation through a focal adhesion kinase (FAK)-independent pathway. In vivo trial demonstrated that grafts containing CD105(-) showed osteocytes embedded in a mineralized matrix, promoted adequate graft integration, increased host vascular infiltration, and efficient intramembranous repairing. In contrast, grafts containing CD105(+) showed deficient endochondral ossification and fibrocartilaginous tissue. Based on the expression of α-actinin, FAKy,(397) and ERK1/2 activation, we define maturation stage as critical for bone graft assembling. By in vitro assays, CD105(-) subpopulation showed superior adhesion efficiency compared to CD105(+) cells. Considering in vitro and in vivo assays, this study suggests that integration of a scaffold with CD105(-) subpopulation at the maturation stage represents an attractive strategy for clinical use in

Efficient molecular mechanics simulations of the folding, orientation, and assembly of peptides in lipid bilayers using an implicit atomic solvation model

Science.gov (United States)

Bordner, Andrew J.; Zorman, Barry; Abagyan, Ruben

2011-10-01

Membrane proteins comprise a significant fraction of the proteomes of sequenced organisms and are the targets of approximately half of marketed drugs. However, in spite of their prevalence and biomedical importance, relatively few experimental structures are available due to technical challenges. Computational simulations can potentially address this deficit by providing structural models of membrane proteins. Solvation within the spatially heterogeneous membrane/solvent environment provides a major component of the energetics driving protein folding and association within the membrane. We have developed an implicit solvation model for membranes that is both computationally efficient and accurate enough to enable molecular mechanics predictions for the folding and association of peptides within the membrane. We derived the new atomic solvation model parameters using an unbiased fitting procedure to experimental data and have applied it to diverse problems in order to test its accuracy and to gain insight into membrane protein folding. First, we predicted the positions and orientations of peptides and complexes within the lipid bilayer and compared the simulation results with solid-state NMR structures. Additionally, we performed folding simulations for a series of host-guest peptides with varying propensities to form alpha helices in a hydrophobic environment and compared the structures with experimental measurements. We were also able to successfully predict the structures of amphipathic peptides as well as the structures for dimeric complexes of short hexapeptides that have experimentally characterized propensities to form beta sheets within the membrane. Finally, we compared calculated relative transfer energies with data from experiments measuring the effects of mutations on the free energies of translocon-mediated insertion of proteins into lipid bilayers and of combined folding and membrane insertion of a beta barrel protein.

De novo transcriptome assembly and comparative analysis of differentially expressed genes in Prunus dulcis Mill. in response to freezing stress.

Directory of Open Access Journals (Sweden)

Sadegh Mousavi

Full Text Available Almond (Prunus dulcis Mill., one of the most important nut crops, requires chilling during winter to develop fruiting buds. However, early spring chilling and late spring frost may damage the reproductive tissues leading to reduction in the rate of productivity. Despite the importance of transcriptional changes and regulation, little is known about the almond's transcriptome under the cold stress conditions. In the current research, we used RNA-seq technique to study the response of the reproductive tissues of almond (anther and ovary to frost stress. RNA sequencing resulted in more than 20 million reads from anther and ovary tissues of almond, individually. About 40,000 contigs were assembled and annotated de novo in each tissue. Profile of gene expression in ovary showed significant alterations in 5,112 genes, whereas in anther 6,926 genes were affected by freezing stress. Around two thousands of these genes were common altered genes in both ovary and anther libraries. Gene ontology indicated the involvement of differentially expressed (DE genes, responding to freezing stress, in metabolic and cellular processes. qRT-PCR analysis verified the expression pattern of eight genes randomly selected from the DE genes. In conclusion, the almond gene index assembled in this study and the reported DE genes can provide great insights on responses of almond and other Prunus species to abiotic stresses. The obtained results from current research would add to the limited available information on almond and Rosaceae. Besides, the findings would be very useful for comparative studies as the number of DE genes reported here is much higher than that of any previous reports in this plant.

De novo transcriptome assembly and comparative analysis of differentially expressed genes in Prunus dulcis Mill. in response to freezing stress.

Science.gov (United States)

Mousavi, Sadegh; Alisoltani, Arghavan; Shiran, Behrouz; Fallahi, Hossein; Ebrahimie, Esameil; Imani, Ali; Houshmand, Saadollah

2014-01-01

Almond (Prunus dulcis Mill.), one of the most important nut crops, requires chilling during winter to develop fruiting buds. However, early spring chilling and late spring frost may damage the reproductive tissues leading to reduction in the rate of productivity. Despite the importance of transcriptional changes and regulation, little is known about the almond's transcriptome under the cold stress conditions. In the current research, we used RNA-seq technique to study the response of the reproductive tissues of almond (anther and ovary) to frost stress. RNA sequencing resulted in more than 20 million reads from anther and ovary tissues of almond, individually. About 40,000 contigs were assembled and annotated de novo in each tissue. Profile of gene expression in ovary showed significant alterations in 5,112 genes, whereas in anther 6,926 genes were affected by freezing stress. Around two thousands of these genes were common altered genes in both ovary and anther libraries. Gene ontology indicated the involvement of differentially expressed (DE) genes, responding to freezing stress, in metabolic and cellular processes. qRT-PCR analysis verified the expression pattern of eight genes randomly selected from the DE genes. In conclusion, the almond gene index assembled in this study and the reported DE genes can provide great insights on responses of almond and other Prunus species to abiotic stresses. The obtained results from current research would add to the limited available information on almond and Rosaceae. Besides, the findings would be very useful for comparative studies as the number of DE genes reported here is much higher than that of any previous reports in this plant.

Anatomical study of minor alterations in neonate vocal folds.

Science.gov (United States)

Silva, Adriano Rezende; Machado, Almiro José; Crespo, Agrício Nubiato

2014-01-01

Minor structural alterations of the vocal fold cover are frequent causes of voice abnormalities. They may be difficult to diagnose, and are expressed in different manners. Cases of intracordal cysts, sulcus vocalis, mucosal bridge, and laryngeal micro-diaphragm form the group of minor structural alterations of the vocal fold cover investigated in the present study. The etiopathogenesis and epidemiology of these alterations are poorly known. To evaluate the existence and anatomical characterization of minor structural alterations in the vocal folds of newborns. 56 larynxes excised from neonates of both genders were studied. They were examined fresh, or defrosted after conservation via freezing, under a microscope at magnifications of 25× and 40×. The vocal folds were inspected and palpated by two examiners, with the aim of finding minor structural alterations similar to those described classically, and other undetermined minor structural alterations. Larynges presenting abnormalities were submitted to histological examination. Six cases of abnormalities were found in different larynges: one (1.79%) compatible with a sulcus vocalis and five (8.93%) compatible with a laryngeal micro-diaphragm. No cases of cysts or mucosal bridges were found. The observed abnormalities had characteristics similar to those described in other age groups. Abnormalities similar to sulcus vocalis or micro-diaphragm may be present at birth. Copyright © 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Structural analysis of sheath folds in the Sylacauga Marble Group, Talladega slate belt, southern Appalachians

Science.gov (United States)

Mies, J.W.

1993-01-01

Remnant blocks of marble from the Moretti-Harrah dimension-stone quarry provide excellent exposure of meter-scale sheath folds. Tubular structures with elliptical cross-sections (4 ???Ryz ??? 5) are the most common expression of the folds. The tubes are elongate subparallel to stretching lineation and are defined by centimeter-scale layers of schist. Eccentrically nested elliptical patterns and opposing asymmetry of folds ('S' and 'Z') are consistent with the sheath-fold interpretation. Sheath folds are locally numerous in the Moretti-Harrah quarry but are not widely distributed in the Sylacauga Marble Group; reconnaissance in neighboring quarries provided no additional observations. The presence of sheath folds in part of the Talladega slate belt indicates a local history of plastic, non-coaxial deformation. Such a history of deformation is substantiated by petrographic study of an extracted hinge from the Moretti-Harrah quarry. The sheath folds are modeled as due to passive amplification of initial structures during simple shear, using both analytic geometry and graphic simulation. As indicated by these models, relatively large shear strains (y ??? 9) and longitudinal initial structures are required. The shear strain presumably relates to NW-directed displacement of overlying crystalline rocks during late Paleozoic orogeny. ?? 1993.

Glass ionomer application for vocal fold augmentation: Histopathological analysis on rabbit vocal fold.

Science.gov (United States)

Demirci, Sule; Tuzuner, Arzu; Callıoglu, Elif Ersoy; Yumusak, Nihat; Arslan, Necmi; Baltacı, Bülent

2016-04-01

The aim of this study was to investigate the use of glass ionomer cement (GIC) as an injection material for vocal fold augmentation and to evaluate the biocompatibility of the material. Ten adult New Zealand rabbits were used. Under general anesthesia, 0.1-cc GIC was injected to one vocal fold and the augmentation of vocal fold was observed. No injection was applied to the opposite side, which was accepted as the control group. The animals were sacrificed after 3 months and the laryngeal specimens were histopathologically evaluated. The injected and the noninjected control vocal folds were analyzed. The GIC particles were observed in histological sections on the injected side, and no foreign body giant cells, granulomatous inflammation, necrosis, or marked chronic inflammation were detected around the glass ionomer particles. Mild inflammatory reactions were noticed in only two specimens. The noninjected sides of vocal folds were completely normal. The findings of this study suggest that GIC is biocompatible and may be further investigated as an alternative injection material for augmentation of the vocal fold. Further studies are required to examine the viscoelastic properties of GIC and the long-term effects in experimental studies. NA. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

Unfolding a molecular trefoil derived from a zwitterionic metallopeptide to form self-assembled nanostructures

KAUST Repository

Zhang, Ye; Zhou, Ning; Shi, Junfeng; Pochapsky, Susan Sondej; Pochapsky, Thomas C.; Zhang, Bei; Zhang, Xixiang; Xu, Bing

2015-01-01

While used extensively by nature to control the geometry of protein structures, and dynamics of proteins, such as self-organization, hydration forces and ionic interactions received less attention for controlling the behaviour of small molecules. Here we describe the synthesis and characterization of a novel zwitterionic metallopeptide consisting of a cationic core and three distal anionic groups linked by self-assembling peptide motifs. 2D NMR spectra, total correlated spectroscopy and nuclear Overhauser effect spectroscopy, show that the molecule exhibits a three-fold rotational symmetry and adopts a folded conformation in dimethyl sulfoxide due to Coulombic forces. When hydrated in water, the molecule unfolds to act as a self-assembling building block of supramolecular nanostructures. By combining ionic interactions with the unique geometry from metal complex and hydrophobic interactions from simple peptides, we demonstrate a new and effective way to design molecules for smart materials through mimicking a sophisticated biofunctional system using a conformational switch.

Unfolding a molecular trefoil derived from a zwitterionic metallopeptide to form self-assembled nanostructures

KAUST Repository

Zhang, Ye

2015-02-19

While used extensively by nature to control the geometry of protein structures, and dynamics of proteins, such as self-organization, hydration forces and ionic interactions received less attention for controlling the behaviour of small molecules. Here we describe the synthesis and characterization of a novel zwitterionic metallopeptide consisting of a cationic core and three distal anionic groups linked by self-assembling peptide motifs. 2D NMR spectra, total correlated spectroscopy and nuclear Overhauser effect spectroscopy, show that the molecule exhibits a three-fold rotational symmetry and adopts a folded conformation in dimethyl sulfoxide due to Coulombic forces. When hydrated in water, the molecule unfolds to act as a self-assembling building block of supramolecular nanostructures. By combining ionic interactions with the unique geometry from metal complex and hydrophobic interactions from simple peptides, we demonstrate a new and effective way to design molecules for smart materials through mimicking a sophisticated biofunctional system using a conformational switch.

A prefoldin-associated WD-repeat protein (WDR92) is required for the correct architectural assembly of motile cilia

Science.gov (United States)

Patel-King, Ramila S.; King, Stephen M.

2016-01-01

WDR92 is a highly conserved WD-repeat protein that has been proposed to be involved in apoptosis and also to be part of a prefoldin-like cochaperone complex. We found that WDR92 has a phylogenetic signature that is generally compatible with it playing a role in the assembly or function of specifically motile cilia. To test this hypothesis, we performed an RNAi-based knockdown of WDR92 gene expression in the planarian Schmidtea mediterranea and were able to achieve a robust reduction in mRNA expression to levels undetectable under our standard RT-PCR conditions. We found that this treatment resulted in a dramatic reduction in the rate of organismal movement that was caused by a switch in the mode of locomotion from smooth, cilia-driven gliding to muscle-based, peristaltic contractions. Although the knockdown animals still assembled cilia of normal length and in similar numbers to controls, these structures had reduced beat frequency and did not maintain hydrodynamic coupling. By transmission electron microscopy we observed that many cilia had pleiomorphic defects in their architecture, including partial loss of dynein arms, incomplete closure of the B-tubule, and occlusion or replacement of the central pair complex by accumulated electron-dense material. These observations suggest that WDR92 is part of a previously unrecognized cytoplasmic chaperone system that is specifically required to fold key components necessary to build motile ciliary axonemes. PMID:26912790

Layer-by-layer cell membrane assembly

Science.gov (United States)

Matosevic, Sandro; Paegel, Brian M.

2013-11-01

Eukaryotic subcellular membrane systems, such as the nuclear envelope or endoplasmic reticulum, present a rich array of architecturally and compositionally complex supramolecular targets that are as yet inaccessible. Here we describe layer-by-layer phospholipid membrane assembly on microfluidic droplets, a route to structures with defined compositional asymmetry and lamellarity. Starting with phospholipid-stabilized water-in-oil droplets trapped in a static droplet array, lipid monolayer deposition proceeds as oil/water-phase boundaries pass over the droplets. Unilamellar vesicles assembled layer-by-layer support functional insertion both of purified and of in situ expressed membrane proteins. Synthesis and chemical probing of asymmetric unilamellar and double-bilayer vesicles demonstrate the programmability of both membrane lamellarity and lipid-leaflet composition during assembly. The immobilized vesicle arrays are a pragmatic experimental platform for biophysical studies of membranes and their associated proteins, particularly complexes that assemble and function in multilamellar contexts in vivo.

HapCol: Accurate and Memory-efficient Haplotype Assembly from Long Reads

NARCIS (Netherlands)

Y. Pirola (Yuri); S. Zaccaria (Simone); R. Dondi (Riccardo); G.W. Klau (Gunnar); N. Pisanti (Nadia); P. Bonizzoni (Paola)

2015-01-01

htmlabstractMotivation: Haplotype assembly is the computational problem of reconstructing haplotypes in diploid organisms and is of fundamental importance for characterizing the effects of single-nucleotide polymorphisms on the expression of phenotypic traits. Haplotype assembly highly benefits from

Rapid customised operon assembly by yeast recombinational cloning.

Science.gov (United States)

Liu, Michael A; Kenyon, Johanna J; Lee, Jason; Reeves, Peter R

2017-06-01

We have developed a system called the Operon Assembly Protocol (OAP), which takes advantage of the homologous recombination DNA repair pathway in Saccharomyces cerevisiae to assemble full-length operons from a series of overlapping PCR products into a specially engineered yeast-Escherichia coli shuttle vector. This flexible, streamlined system can be used to assemble several operon clones simultaneously, and each clone can be expressed in the same E. coli tester strain to facilitate direct functional comparisons. We demonstrated the utility of the OAP by assembling and expressing a series of E. coli O1A O-antigen gene cluster clones containing various gene deletions or replacements. We then used these constructs to assess the substrate preferences of several Wzx flippases, which are responsible for translocation of oligosaccharide repeat units (O units) across the inner membrane during O-antigen biosynthesis. We were able to identify several O unit structural features that appear to be important determinants of Wzx substrate preference. The OAP system should be broadly applicable for the genetic manipulation of any bacterial operon and can be modified for use in other host species. It could also have potential uses in fields such as glycoengineering.

Expression, purification, crystallization and preliminary X-ray characterization of a putative glycosyltransferase of the GT-A fold found in mycobacteria

Energy Technology Data Exchange (ETDEWEB)

Fulton, Zara; Crellin, Paul K.; Brammananth, Rajini; Zaker-Tabrizi, Leyla; Coppel, Ross L.; Rossjohna, Jamie; Beddoe, Travis (Monash)

2008-05-28

Glycosidic bond formation is a ubiquitous enzyme-catalysed reaction. This glycosyltransferase-mediated process is responsible for the biosynthesis of innumerable oligosaccharides and glycoconjugates and is often organism- or cell-specific. However, despite the abundance of genomic information on glycosyltransferases (GTs), there is a lack of structural data for this versatile class of enzymes. Here, the cloning, expression, purification and crystallization of an essential 329-amino-acid (34.8 kDa) putative GT of the classic GT-A fold implicated in mycobacterial cell-wall biosynthesis are reported. Crystals of MAP2569c from Mycobacterium avium subsp. paratuberculosis were grown in 1.6 M monoammonium dihydrogen phosphate and 0.1 M sodium citrate pH 5.5. A complete data set was collected to 1.8 {angstrom} resolution using synchrotron radiation from a crystal belonging to space group P4{sub 1}2{sub 1}2.

Periodic folding of viscous sheets

Science.gov (United States)

Ribe, Neil M.

2003-09-01

The periodic folding of a sheet of viscous fluid falling upon a rigid surface is a common fluid mechanical instability that occurs in contexts ranging from food processing to geophysics. Asymptotic thin-layer equations for the combined stretching-bending deformation of a two-dimensional sheet are solved numerically to determine the folding frequency as a function of the sheet’s initial thickness, the pouring speed, the height of fall, and the fluid properties. As the buoyancy increases, the system bifurcates from “forced” folding driven kinematically by fluid extrusion to “free” folding in which viscous resistance to bending is balanced by buoyancy. The systematics of the numerically predicted folding frequency are in good agreement with laboratory experiments.

Defined DNA-mediated assemblies of gene-expressing giant unilamellar vesicles

DEFF Research Database (Denmark)

Hadorn, M.; Boenzli, E.; Sørensen, Kristian T.

2013-01-01

The technological aspects of artificial vesicles as prominent cell mimics are evolving toward higher-order assemblies of functional vesicles with tissuelike architectures. Here, we demonstrate the spatially controlled DNA-directed bottom-up synthesis of complex microassemblies and macroassemblies...

HapCol : Accurate and memory-efficient haplotype assembly from long reads

NARCIS (Netherlands)

Pirola, Yuri; Zaccaria, Simone; Dondi, Riccardo; Klau, Gunnar W.; Pisanti, Nadia; Bonizzoni, Paola

2016-01-01

Motivation: Haplotype assembly is the computational problem of reconstructing haplotypes in diploid organisms and is of fundamental importance for characterizing the effects of single-nucleotide polymorphisms on the expression of phenotypic traits. Haplotype assembly highly benefits from the advent

Rheological Behavior of Dense Assemblies of Granular Materials

International Nuclear Information System (INIS)

Sundaresan, Sankaran; Tardos, Gabriel I.; Subramaniam, Shankar

2011-01-01

Assemblies of granular materials behave differently when they are owing rapidly, from when they are slowly deforming. The behavior of rapidly owing granular materials, where the particle-particle interactions occur largely through binary collisions, is commonly related to the properties of the constituent particles through the kinetic theory of granular materials. The same cannot be said for slowly moving or static assemblies of granular materials, where enduring contacts between particles are prevalent. For instance, a continuum description of the yield characteristics of dense assemblies of particles in the quasistatic ow regime cannot be written explicitly on the basis of particle properties, even for cohesionless particles. Continuum models for this regime have been proposed and applied, but these models typically assume that the assembly is at incipient yield and they are expressed in terms of the yield function, which we do not yet know how to express in terms of particle-level properties. The description of the continuum rheology in the intermediate regime is even less understood. Yet, many practically important flows in nature and in a wide range of technological applications occur in the dense flow regime and at the transition between dilute and dense regimes; the lack of validated continuum rheological models for particle assemblies in these regimes limits predictive modeling of such flows. This research project is aimed at developing such rheological models.

Quantitative self-assembly prediction yields targeted nanomedicines

Science.gov (United States)

Shamay, Yosi; Shah, Janki; Işık, Mehtap; Mizrachi, Aviram; Leibold, Josef; Tschaharganeh, Darjus F.; Roxbury, Daniel; Budhathoki-Uprety, Januka; Nawaly, Karla; Sugarman, James L.; Baut, Emily; Neiman, Michelle R.; Dacek, Megan; Ganesh, Kripa S.; Johnson, Darren C.; Sridharan, Ramya; Chu, Karen L.; Rajasekhar, Vinagolu K.; Lowe, Scott W.; Chodera, John D.; Heller, Daniel A.

2018-02-01

Development of targeted nanoparticle drug carriers often requires complex synthetic schemes involving both supramolecular self-assembly and chemical modification. These processes are generally difficult to predict, execute, and control. We describe herein a targeted drug delivery system that is accurately and quantitatively predicted to self-assemble into nanoparticles based on the molecular structures of precursor molecules, which are the drugs themselves. The drugs assemble with the aid of sulfated indocyanines into particles with ultrahigh drug loadings of up to 90%. We devised quantitative structure-nanoparticle assembly prediction (QSNAP) models to identify and validate electrotopological molecular descriptors as highly predictive indicators of nano-assembly and nanoparticle size. The resulting nanoparticles selectively targeted kinase inhibitors to caveolin-1-expressing human colon cancer and autochthonous liver cancer models to yield striking therapeutic effects while avoiding pERK inhibition in healthy skin. This finding enables the computational design of nanomedicines based on quantitative models for drug payload selection.

Variation in the Subcellular Localization and Protein Folding Activity among Arabidopsis thaliana Homologs of Protein Disulfide Isomerase

Directory of Open Access Journals (Sweden)

Christen Y. L. Yuen

2013-10-01

Full Text Available Protein disulfide isomerases (PDIs catalyze the formation, breakage, and rearrangement of disulfide bonds to properly fold nascent polypeptides within the endoplasmic reticulum (ER. Classical animal and yeast PDIs possess two catalytic thioredoxin-like domains (a, a′ and two non-catalytic domains (b, b′, in the order a-b-b′-a′. The model plant, Arabidopsis thaliana, encodes 12 PDI-like proteins, six of which possess the classical PDI domain arrangement (AtPDI1 through AtPDI6. Three additional AtPDIs (AtPDI9, AtPDI10, AtPDI11 possess two thioredoxin domains, but without intervening b-b′ domains. C-terminal green fluorescent protein (GFP fusions to each of the nine dual-thioredoxin PDI homologs localized predominantly to the ER lumen when transiently expressed in protoplasts. Additionally, expression of AtPDI9:GFP-KDEL and AtPDI10: GFP-KDDL was associated with the formation of ER bodies. AtPDI9, AtPDI10, and AtPDI11 mediated the oxidative folding of alkaline phosphatase when heterologously expressed in the Escherichia coli protein folding mutant, dsbA−. However, only three classical AtPDIs (AtPDI2, AtPDI5, AtPDI6 functionally complemented dsbA−. Interestingly, chemical inducers of the ER unfolded protein response were previously shown to upregulate most of the AtPDIs that complemented dsbA−. The results indicate that Arabidopsis PDIs differ in their localization and protein folding activities to fulfill distinct molecular functions in the ER.

Assembly of the epithelial Na+ channel evaluated using sucrose gradient sedimentation analysis.

Science.gov (United States)

Cheng, C; Prince, L S; Snyder, P M; Welsh, M J

1998-08-28

Three subunits, alpha, beta, and gamma, contribute to the formation of the epithelial Na+ channel. To investigate the oligomeric assembly of the channel complex, we used sucrose gradient sedimentation analysis to determine the sedimentation properties of individual subunits and heteromultimers comprised of multiple subunits. When the alpha subunit was expressed alone, it first formed an oligomeric complex with a sedimentation coefficient of 11 S, and then generated a higher order multimer of 25 S. In contrast, individual beta and gamma subunits predominately assembled into 11 S complexes. We obtained similar results with expression in cells and in vitro. When we co-expressed beta with alpha or with alpha plus gamma, the beta subunit assembled into a 25 S complex. Glycosylation of the alpha subunit was not required for assembly into a 25 S complex. We found that the alpha subunit formed intra-chain disulfide bonds. Although such bonds were not required to generate an oligomeric complex, under nonreducing conditions the alpha subunit formed a complex that migrated more homogeneously at 25 S. This suggests that intra-chain disulfide bonds may stabilize the complex. These data suggest that the epithelial Na+ channel subunits form high order oligomeric complexes and that the alpha subunit contains the information that facilitates such formation. Interestingly, the ability of the alpha, but not the beta or gamma, subunit to assemble into a 25 S homomeric complex correlates with the ability of these subunits to generate functional channels when expressed alone.

Asymmetric hindwing foldings in rove beetles.

Science.gov (United States)

Saito, Kazuya; Yamamoto, Shuhei; Maruyama, Munetoshi; Okabe, Yoji

2014-11-18

Foldable wings of insects are the ultimate deployable structures and have attracted the interest of aerospace engineering scientists as well as entomologists. Rove beetles are known to fold their wings in the most sophisticated ways that have right-left asymmetric patterns. However, the specific folding process and the reason for this asymmetry remain unclear. This study reveals how these asymmetric patterns emerge as a result of the folding process of rove beetles. A high-speed camera was used to reveal the details of the wing-folding movement. The results show that these characteristic asymmetrical patterns emerge as a result of simultaneous folding of overlapped wings. The revealed folding mechanisms can achieve not only highly compact wing storage but also immediate deployment. In addition, the right and left crease patterns are interchangeable, and thus each wing internalizes two crease patterns and can be folded in two different ways. This two-way folding gives freedom of choice for the folding direction to a rove beetle. The use of asymmetric patterns and the capability of two-way folding are unique features not found in artificial structures. These features have great potential to extend the design possibilities for all deployable structures, from space structures to articles of daily use.

Selecting Superior De Novo Transcriptome Assemblies: Lessons Learned by Leveraging the Best Plant Genome.

Directory of Open Access Journals (Sweden)

Loren A Honaas

Full Text Available Whereas de novo assemblies of RNA-Seq data are being published for a growing number of species across the tree of life, there are currently no broadly accepted methods for evaluating such assemblies. Here we present a detailed comparison of 99 transcriptome assemblies, generated with 6 de novo assemblers including CLC, Trinity, SOAP, Oases, ABySS and NextGENe. Controlled analyses of de novo assemblies for Arabidopsis thaliana and Oryza sativa transcriptomes provide new insights into the strengths and limitations of transcriptome assembly strategies. We find that the leading assemblers generate reassuringly accurate assemblies for the majority of transcripts. At the same time, we find a propensity for assemblers to fail to fully assemble highly expressed genes. Surprisingly, the instance of true chimeric assemblies is very low for all assemblers. Normalized libraries are reduced in highly abundant transcripts, but they also lack 1000s of low abundance transcripts. We conclude that the quality of de novo transcriptome assemblies is best assessed through consideration of a combination of metrics: 1 proportion of reads mapping to an assembly 2 recovery of conserved, widely expressed genes, 3 N50 length statistics, and 4 the total number of unigenes. We provide benchmark Illumina transcriptome data and introduce SCERNA, a broadly applicable modular protocol for de novo assembly improvement. Finally, our de novo assembly of the Arabidopsis leaf transcriptome revealed ~20 putative Arabidopsis genes lacking in the current annotation.

Quantification of fold growth of frontal antiforms in the Zagros fold and thrust belt (Kurdistan, NE Iraq)

Science.gov (United States)

Bretis, Bernhard; Bartl, Nikolaus; Graseman, Bernhard; Lockhart, Duncan

2010-05-01

The Zagros fold and thrust belt is a seismically active orogen, where actual kinematic models based on GPS networks suggest a north-south shortening between Arabian and Eurasian in the order of 1.5-2.5 cm/yr. Most of this deformation is partitioned in south-southwest oriented folding and thrusting with northwest-southeast to north-south trending dextral strike slip faults. The Zagros fold and thrust belt is of great economic interest because it has been estimated that this area contains about 15% of the global recoverable hydrocarbons. Whereas the SE parts of the Zagros have been investigated by detailed geological studies, the NW extent being part of the Republic of Iraq have experienced considerably less attention. In this study we combine field work and remote sensing techniques in order to investigate the interaction of erosion and fold growth in the area NE of Erbil (Kurdistan, Iraq). In particular we focus on the interaction of the transient development of drainage patterns along growing antiforms, which directly reflects the kinematics of progressive fold growth. Detailed geomorphological studies of the Bana Bawi-, Permam- and Safeen fold trains show that these anticlines have not developed from subcylindrical embryonic folds but they have merged from different fold segments that joined laterally during fold amplification. This fold segments with length between 5 and 25 km have been detected by mapping ancient and modern river courses that initially cut the nose of growing folds and eventually got defeated leaving behind a wind gap. Fold segments, propagating in different directions force rivers to join resulting in steep gorges, which dissect the merging fold noses. Along rapidly lateral growing folds (e.g. at the SE end of the Bana Bawi Anticline) we observed "curved wind gaps", a new type of abandoned river course, where form of the wind gap mimics a formed nose of a growing antiform. The inherited curved segments of uplifted curved river courses strongly

The mechanics of fault-bend folding and tear-fault systems in the Niger Delta

Science.gov (United States)

Benesh, Nathan Philip

This dissertation investigates the mechanics of fault-bend folding using the discrete element method (DEM) and explores the nature of tear-fault systems in the deep-water Niger Delta fold-and-thrust belt. In Chapter 1, we employ the DEM to investigate the development of growth structures in anticlinal fault-bend folds. This work was inspired by observations that growth strata in active folds show a pronounced upward decrease in bed dip, in contrast to traditional kinematic fault-bend fold models. Our analysis shows that the modeled folds grow largely by parallel folding as specified by the kinematic theory; however, the process of folding over a broad axial surface zone yields a component of fold growth by limb rotation that is consistent with the patterns observed in natural folds. This result has important implications for how growth structures can he used to constrain slip and paleo-earthquake ages on active blind-thrust faults. In Chapter 2, we expand our DEM study to investigate the development of a wider range of fault-bend folds. We examine the influence of mechanical stratigraphy and quantitatively compare our models with the relationships between fold and fault shape prescribed by the kinematic theory. While the synclinal fault-bend models closely match the kinematic theory, the modeled anticlinal fault-bend folds show robust behavior that is distinct from the kinematic theory. Specifically, we observe that modeled structures maintain a linear relationship between fold shape (gamma) and fault-horizon cutoff angle (theta), rather than expressing the non-linear relationship with two distinct modes of anticlinal folding that is prescribed by the kinematic theory. These observations lead to a revised quantitative relationship for fault-bend folds that can serve as a useful interpretation tool. Finally, in Chapter 3, we examine the 3D relationships of tear- and thrust-fault systems in the western, deep-water Niger Delta. Using 3D seismic reflection data and new

Self-assembling layers created by membrane proteins on gold.

Science.gov (United States)

Shah, D S; Thomas, M B; Phillips, S; Cisneros, D A; Le Brun, A P; Holt, S A; Lakey, J H

2007-06-01

Membrane systems are based on several types of organization. First, amphiphilic lipids are able to create monolayer and bilayer structures which may be flat, vesicular or micellar. Into these structures membrane proteins can be inserted which use the membrane to provide signals for lateral and orientational organization. Furthermore, the proteins are the product of highly specific self-assembly otherwise known as folding, which mostly places individual atoms at precise places in three dimensions. These structures all have dimensions in the nanoscale, except for the size of membrane planes which may extend for millimetres in large liposomes or centimetres on planar surfaces such as monolayers at the air/water interface. Membrane systems can be assembled on to surfaces to create supported bilayers and these have uses in biosensors and in electrical measurements using modified ion channels. The supported systems also allow for measurements using spectroscopy, surface plasmon resonance and atomic force microscopy. By combining the roles of lipids and proteins, highly ordered and specific structures can be self-assembled in aqueous solution at the nanoscale.

The Effect of Laminin-1-Doped Nanoroughened Implant Surfaces: Gene Expression and Morphological Evaluation

Directory of Open Access Journals (Sweden)

Humberto Osvaldo Schwartz-Filho

2012-01-01

Full Text Available Aim. This study aimed to observe the morphological and molecular effect of laminin-1 doping to nanostructured implant surfaces in a rabbit model. Materials and Methods. Nanostructured implants were coated with laminin-1 (test; dilution, 100 μg/mL and inserted into the rabbit tibiae. Noncoated implants were used as controls. After 2 weeks of healing, the implants were removed and subjected to morphological analysis using scanning electron microscopy (SEM and gene expression analysis using the real-time reverse transcriptase-polymerase chain reaction (RT-PCR. Results. SEM revealed bony tissue attachment for both control and test implants. Real-time RT-PCR analysis showed that the expression of osteoblast markers RUNX-2, osteocalcin, alkaline phosphatase, and collagen I was higher (1.62-fold, 1.53-fold, 1.97-fold, and 1.04-fold, resp. for the implants modified by laminin-1 relative to the control. All osteoclast markers investigated in the study presented higher expression on the test implants than controls as follows: tartrate-resistant acid phosphatase (1.67-fold, calcitonin receptor (1.35-fold, and ATPase (1.25-fold. The test implants demonstrated higher expression of inflammatory markers interleukin-10 (1.53-fold and tumour necrosis factor-α (1.61-fold relative to controls. Conclusion. The protein-doped surface showed higher gene expression of typical genes involved in the osseointegration cascade than the control surface.

A pH-Regulated Quality Control Cycle for Surveillance of Secretory Protein Assembly

Science.gov (United States)

Vavassori, Stefano; Cortini, Margherita; Masui, Shoji; Sannino, Sara; Anelli, Tiziana; Caserta, Imma R.; Fagioli, Claudio; Mossuto, Maria F.; Fornili, Arianna; van Anken, Eelco; Degano, Massimo; Inaba, Kenji; Sitia, Roberto

2013-01-01

Summary To warrant the quality of the secretory proteome, stringent control systems operate at the endoplasmic reticulum (ER)-Golgi interface, preventing the release of nonnative products. Incompletely assembled oligomeric proteins that are deemed correctly folded must rely on additional quality control mechanisms dedicated to proper assembly. Here we unveil how ERp44 cycles between cisGolgi and ER in a pH-regulated manner, patrolling assembly of disulfide-linked oligomers such as IgM and adiponectin. At neutral, ER-equivalent pH, the ERp44 carboxy-terminal tail occludes the substrate-binding site. At the lower pH of the cisGolgi, conformational rearrangements of this peptide, likely involving protonation of ERp44’s active cysteine, simultaneously unmask the substrate binding site and −RDEL motif, allowing capture of orphan secretory protein subunits and ER retrieval via KDEL receptors. The ERp44 assembly control cycle couples secretion fidelity and efficiency downstream of the calnexin/calreticulin and BiP-dependent quality control cycles. PMID:23685074

Fractal Folding and Medium Viscoelasticity Contribute Jointly to Chromosome Dynamics

Science.gov (United States)

Polovnikov, K. E.; Gherardi, M.; Cosentino-Lagomarsino, M.; Tamm, M. V.

2018-02-01

Chromosomes are key players of cell physiology, their dynamics provides valuable information about its physical organization. In both prokaryotes and eukaryotes, the short-time motion of chromosomal loci has been described with a Rouse model in a simple or viscoelastic medium. However, little emphasis has been put on the influence of the folded organization of chromosomes on the local dynamics. Clearly, stress propagation, and thus dynamics, must be affected by such organization, but a theory allowing us to extract such information from data, e.g., on two-point correlations, is lacking. Here, we describe a theoretical framework able to answer this general polymer dynamics question. We provide a scaling analysis of the stress-propagation time between two loci at a given arclength distance along the chromosomal coordinate. The results suggest a precise way to assess folding information from the dynamical coupling of chromosome segments. Additionally, we realize this framework in a specific model of a polymer whose long-range interactions are designed to make it fold in a fractal way and immersed in a medium characterized by subdiffusive fractional Langevin motion with a tunable scaling exponent. This allows us to derive explicit analytical expressions for the correlation functions.

Exercise-induced liver chemokine CXCL-1 expression is linked to muscle-derived interleukin-6 expression

DEFF Research Database (Denmark)

Pedersen, Line; Pilegaard, Henriette; Hansen, Jakob

2011-01-01

interleukin-6 (IL-6) and muscle IL-6 mRNA. In contrast, exercise-induced regulation of liver CXCL-1 mRNA expression was completely blunted in IL-6 knockout mice. Based on these findings, we examined the possible existence of a muscle-to-liver axis by overexpressing IL-6 in muscles. This resulted in increases...... in serum CXCL-1 (5-fold) and liver CXCL-1 mRNA expression (24-fold) compared with control. Because IL-6 expression and release are known to be augmented during exercise in glycogen-depleted animals, CXCL-1 and IL-6 expression were examined after exercise in overnight-fasted mice.We found that fasting...... significantly augmented serum CXCL-1, and CXCL-1 expression in liver and muscle. Taken together, these data indicate that liver is the main source of serum CXCL-1 during exercise in mice, and that the CXCL-1 expression in the liver is regulated by muscle-derived IL-6....

Involvement and necessity of the Cpx regulon in the event of aberrant β-barrel outer membrane protein assembly

Science.gov (United States)

Gerken, Henri; Leiser, Owen P.; Bennion, Drew; Misra, Rajeev

2010-01-01

Summary The Cpx and σE regulons help maintain outer membrane integrity; the Cpx pathway monitors the biogenesis of cell surface structures, such as pili, while the σE pathway monitors the biogenesis of β-barrel outer membrane proteins (OMPs). In this study we revealed the importance of the Cpx regulon in the event of β-barrel OMP mis-assembly, by utilizing mutants expressing either a defective β-barrel OMP assembly machinery (Bam) or assembly defective β-barrel OMPs. Analysis of specific mRNAs showed that ΔcpxR bam double mutants failed to induce degP expression beyond the wild type level, despite activation of the σE pathway. The synthetic conditional lethal phenotype of ΔcpxR in mutant Bam or β-barrel OMP backgrounds was reversed by wild type DegP expressed from a heterologous plasmid promoter. Consistent with the involvement of the Cpx regulon in the event of aberrant β-barrel OMP assembly, the expression of cpxP, the archetypal member of the cpx regulon, was upregulated in defective Bam backgrounds or in cells expressing a single assembly-defective β-barrel OMP species. Together, these results showed that both the Cpx and σE regulons are required to reduce envelope stress caused by aberrant β-barrel OMP assembly, with the Cpx regulon principally contributing by controlling degP expression. PMID:20487295

A puzzle assembly strategy for fabrication of large engineered cartilage tissue constructs.

Science.gov (United States)

Nover, Adam B; Jones, Brian K; Yu, William T; Donovan, Daniel S; Podolnick, Jeremy D; Cook, James L; Ateshian, Gerard A; Hung, Clark T

2016-03-21

Engineering of large articular cartilage tissue constructs remains a challenge as tissue growth is limited by nutrient diffusion. Here, a novel strategy is investigated, generating large constructs through the assembly of individually cultured, interlocking, smaller puzzle-shaped subunits. These constructs can be engineered consistently with more desirable mechanical and biochemical properties than larger constructs (~4-fold greater Young׳s modulus). A failure testing technique was developed to evaluate the physiologic functionality of constructs, which were cultured as individual subunits for 28 days, then assembled and cultured for an additional 21-35 days. Assembled puzzle constructs withstood large deformations (40-50% compressive strain) prior to failure. Their ability to withstand physiologic loads may be enhanced by increases in subunit strength and assembled culture time. A nude mouse model was utilized to show biocompatibility and fusion of assembled puzzle pieces in vivo. Overall, the technique offers a novel, effective approach to scaling up engineered tissues and may be combined with other techniques and/or applied to the engineering of other tissues. Future studies will aim to optimize this system in an effort to engineer and integrate robust subunits to fill large defects. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of nonylphenol on gene expression in Atlantic salmon smolts

Energy Technology Data Exchange (ETDEWEB)

Robertson, Laura S., E-mail: lrobertson@usgs.gov [USGS, Leetown Science Center, 11649 Leetown Road, Kearneysville, WV 25430 (United States); McCormick, Stephen D., E-mail: smccormick@usgs.gov [USGS, Leetown Science Center, Conte Anadromous Fish Research Center, Turners Falls, MA 01376 (United States)

2012-10-15

The parr-smolt transformation in Atlantic salmon (Salmo salar) is a complex developmental process that culminates in the ability to migrate to and live in seawater. Exposure to environmental contaminants like nonylphenol can disrupt smolt development and may be a contributing factor in salmon population declines. We used GRASP 16K cDNA microarrays to investigate the effects of nonylphenol on gene expression in Atlantic salmon smolts. Nonylphenol exposure reduced gill Na{sup +}/K{sup +}-ATPase activity and plasma cortisol and triiodothyronine levels. Transcriptional responses were examined in gill, liver, olfactory rosettes, hypothalamus, and pituitary. Expression of 124 features was significantly altered in the liver of fish exposed to nonylphenol; little to no transcriptional effects were observed in other tissues. mRNA abundance of genes involved in protein biosynthesis, folding, modification, transport and catabolism; nucleosome assembly, cell cycle, cell differentiation, microtubule-based movement, electron transport, and response to stress increased in nonylphenol-treated fish. This study expands our understanding of the effect of nonylphenol on smolting and provides potential targets for development of biomarkers.

Tips and tricks for the assembly of a Corynebacterium pseudotuberculosis genome using a semiconductor sequencer

DEFF Research Database (Denmark)

Ramos, Rommel Thiago Jucá; Carneiro, Adriana Ribeiro; Soares, Siomar de Castro

2013-01-01

that enable reference-based assembly, such as the one used in the present study, Corynebacterium pseudotuberculosis biovar equi, which causes high economic losses in the US equine industry. The quality treatment strategy incorporated into the assembly pipeline enabled a 16-fold greater use of the sequencing...... was validated by comparative genomics with other species of the genus Corynebacterium. The present study presents a modus operandi that enables a greater and better use of data obtained from semiconductor sequencing for obtaining the complete genome from a prokaryotic microorganism, C. pseudotuberculosis, which...

Narrowing the diversification of supramolecular assemblies by preorganization.

Science.gov (United States)

Wang, Zhongyan; Liang, Chunhui; Shang, Yuna; He, Shuangshuang; Wang, Ling; Yang, Zhimou

2018-03-13

We designed and synthesized three phosphorylated peptides as precursors of the same peptide Nap-YYY. We found that different precursors led to different materials with almost identical chemical compositions at the final stages. Only Nap-YpYY could form very uniform nanofibers in a stable supramolecular hydrogel by enzyme-instructed self-assembly (EISA) at the physiological temperature (37 °C). In contrast, de-phosphorylation of the other two precursors (Nap-pYYY and Nap-YYpY) resulted in diverse nanostructures in metastable hydrogels with precipitates. The formation of uniform nanomaterials in the stable hydrogels was due to the preorganization property of the precursor Nap-YpYY, which facilitated rapid folding and accelerated the kinetics of hydrogelation of the resulting peptide Nap-YYY generated by the EISA process. Our study demonstrated the importance of the precursor for the self-assembly of nanomaterials and provided a useful strategy to manipulate them.

Spherical images and inextensible curved folding

Science.gov (United States)

Seffen, Keith A.

2018-02-01

In their study, Duncan and Duncan [Proc. R. Soc. London A 383, 191 (1982), 10.1098/rspa.1982.0126] calculate the shape of an inextensible surface folded in two about a general curve. They find the analytical relationships between pairs of generators linked across the fold curve, the shape of the original path, and the fold angle variation along it. They present two special cases of generator layouts for which the fold angle is uniform or the folded curve remains planar, for simplifying practical folding in sheet-metal processes. We verify their special cases by a graphical treatment according to a method of Gauss. We replace the fold curve by a piecewise linear path, which connects vertices of intersecting pairs of hinge lines. Inspired by the d-cone analysis by Farmer and Calladine [Int. J. Mech. Sci. 47, 509 (2005), 10.1016/j.ijmecsci.2005.02.013], we construct the spherical images for developable folding of successive vertices: the operating conditions of the special cases in Duncan and Duncan are then revealed straightforwardly by the geometric relationships between the images. Our approach may be used to synthesize folding patterns for novel deployable and shape-changing surfaces without need of complex calculation.

Destiny of autologous bone marrow-derived stromal cells implanted in the vocal fold.

Science.gov (United States)

Kanemaru, Shin-ichi; Nakamura, Tatsuo; Yamashita, Masaru; Magrufov, Akhmar; Kita, Tomoko; Tamaki, Hisanobu; Tamura, Yoshihiro; Iguchi, Fuku-ichiro; Kim, Tae Soo; Kishimoto, Masanao; Omori, Koichi; Ito, Juichi

2005-12-01

The aim of this study was to investigate the destiny of implanted autologous bone marrow-derived stromal cells (BSCs) containing mesenchymal stem cells. We previously reported the successful regeneration of an injured vocal fold through implantation of BSCs in a canine model. However, the fate of the implanted BSCs was not examined. In this study, implanted BSCs were traced in order to determine the type of tissues resulting at the injected site of the vocal fold. After harvest of bone marrow from the femurs of green fluorescent transgenic mice, adherent cells were cultured and selectively amplified. By means of a fluorescence-activated cell sorter, it was confirmed that some cells were strongly positive for mesenchymal stem cell markers, including CD29, CD44, CD49e, and Sca-1. These cells were then injected into the injured vocal fold of a nude rat. Immunohistologic examination of the resected vocal folds was performed 8 weeks after treatment. The implanted cells were alive in the host tissues and showed positive expression for keratin and desmin, markers for epithelial tissue and muscle, respectively. The implanted BSCs differentiated into more than one tissue type in vivo. Cell-based tissue engineering using BSCs may improve the quality of the healing process in vocal fold injuries.

Characterization of Trichome-Expressed BAHD Acyltransferases in Petunia axillaris Reveals Distinct Acylsugar Assembly Mechanisms within the Solanaceae.

Science.gov (United States)

Nadakuduti, Satya Swathi; Uebler, Joseph B; Liu, Xiaoxiao; Jones, A Daniel; Barry, Cornelius S

2017-09-01

Acylsugars are synthesized in the glandular trichomes of the Solanaceae family and are implicated in protection against abiotic and biotic stress. Acylsugars are composed of either sucrose or glucose esterified with varying numbers of acyl chains of differing length. In tomato ( Solanum lycopersicum ), acylsugar assembly requires four acylsugar acyltransferases (ASATs) of the BAHD superfamily. Tomato ASATs catalyze the sequential esterification of acyl-coenzyme A thioesters to the R4, R3, R3', and R2 positions of sucrose, yielding a tetra-acylsucrose. Petunia spp. synthesize acylsugars that are structurally distinct from those of tomato. To explore the mechanisms underlying this chemical diversity, a Petunia axillaris transcriptome was mined for trichome preferentially expressed BAHDs. A combination of phylogenetic analyses, gene silencing, and biochemical analyses coupled with structural elucidation of metabolites revealed that acylsugar assembly is not conserved between tomato and petunia. In P. axillaris , tetra-acylsucrose assembly occurs through the action of four ASATs, which catalyze sequential addition of acyl groups to the R2, R4, R3, and R6 positions. Notably, in P. axillaris , PaxASAT1 and PaxASAT4 catalyze the acylation of the R2 and R6 positions of sucrose, respectively, and no clear orthologs exist in tomato. Similarly, petunia acylsugars lack an acyl group at the R3' position, and congruently, an ortholog of SlASAT3, which catalyzes acylation at the R3' position in tomato, is absent in P. axillaris Furthermore, where putative orthologous relationships of ASATs are predicted between tomato and petunia, these are not supported by biochemical assays. Overall, these data demonstrate the considerable evolutionary plasticity of acylsugar biosynthesis. © 2017 American Society of Plant Biologists. All Rights Reserved.

A part toolbox to tune genetic expression in Bacillus subtilis

Science.gov (United States)

Guiziou, Sarah; Sauveplane, Vincent; Chang, Hung-Ju; Clerté, Caroline; Declerck, Nathalie; Jules, Matthieu; Bonnet, Jerome

2016-01-01

Libraries of well-characterised components regulating gene expression levels are essential to many synthetic biology applications. While widely available for the Gram-negative model bacterium Escherichia coli, such libraries are lacking for the Gram-positive model Bacillus subtilis, a key organism for basic research and biotechnological applications. Here, we engineered a genetic toolbox comprising libraries of promoters, Ribosome Binding Sites (RBS), and protein degradation tags to precisely tune gene expression in B. subtilis. We first designed a modular Expression Operating Unit (EOU) facilitating parts assembly and modifications and providing a standard genetic context for gene circuits implementation. We then selected native, constitutive promoters of B. subtilis and efficient RBS sequences from which we engineered three promoters and three RBS sequence libraries exhibiting ∼14 000-fold dynamic range in gene expression levels. We also designed a collection of SsrA proteolysis tags of variable strength. Finally, by using fluorescence fluctuation methods coupled with two-photon microscopy, we quantified the absolute concentration of GFP in a subset of strains from the library. Our complete promoters and RBS sequences library comprising over 135 constructs enables tuning of GFP concentration over five orders of magnitude, from 0.05 to 700 μM. This toolbox of regulatory components will support many research and engineering applications in B. subtilis. PMID:27402159

Folded three-spin string solutions in AdS5 x S5

International Nuclear Information System (INIS)

Ryang Shijong

2004-01-01

We construct a spinning closed string solution in AdS 5 x S 5 which is folded in the radial direction and has two equal spins in AdS 5 and a spin in S 5 . The energy expression of the three-spin solution specified by the folding and winding numbers for the small S 5 spin shows a logarithmic behavior and a one-third power behavior of the large total AdS 5 spin, in the long string and in the short string located near the boundary of AdS 5 respectively. It exhibits the non-regular expansion in the 't Hooft coupling constant, while it takes the regular one when the S 5 spin becomes large. (author)

Digital Gene Expression Analysis Based on De Novo Transcriptome Assembly Reveals New Genes Associated with Floral Organ Differentiation of the Orchid Plant Cymbidium ensifolium.

Directory of Open Access Journals (Sweden)

Fengxi Yang

Full Text Available Cymbidium ensifolium belongs to the genus Cymbidium of the orchid family. Owing to its spectacular flower morphology, C. ensifolium has considerable ecological and cultural value. However, limited genetic data is available for this non-model plant, and the molecular mechanism underlying floral organ identity is still poorly understood. In this study, we characterize the floral transcriptome of C. ensifolium and present, for the first time, extensive sequence and transcript abundance data of individual floral organs. After sequencing, over 10 Gb clean sequence data were generated and assembled into 111,892 unigenes with an average length of 932.03 base pairs, including 1,227 clusters and 110,665 singletons. Assembled sequences were annotated with gene descriptions, gene ontology, clusters of orthologous group terms, the Kyoto Encyclopedia of Genes and Genomes, and the plant transcription factor database. From these annotations, 131 flowering-associated unigenes, 61 CONSTANS-LIKE (COL unigenes and 90 floral homeotic genes were identified. In addition, four digital gene expression libraries were constructed for the sepal, petal, labellum and gynostemium, and 1,058 genes corresponding to individual floral organ development were identified. Among them, eight MADS-box genes were further investigated by full-length cDNA sequence analysis and expression validation, which revealed two APETALA1/AGL9-like MADS-box genes preferentially expressed in the sepal and petal, two AGAMOUS-like genes particularly restricted to the gynostemium, and four DEF-like genes distinctively expressed in different floral organs. The spatial expression of these genes varied distinctly in different floral mutant corresponding to different floral morphogenesis, which validated the specialized roles of them in floral patterning and further supported the effectiveness of our in silico analysis. This dataset generated in our study provides new insights into the molecular mechanisms

Supramolecular Architectures and Mimics of Complex Natural Folds Derived from Rationally Designed alpha-Helical Protein Structures

Science.gov (United States)

Tavenor, Nathan Albert

Protein-based supramolecular polymers (SMPs) are a class of biomaterials which draw inspiration from and expand upon the many examples of complex protein quaternary structures observed in nature: collagen, microtubules, viral capsids, etc. Designing synthetic supramolecular protein scaffolds both increases our understanding of natural superstructures and allows for the creation of novel materials. Similar to small-molecule SMPs, protein-based SMPs form due to self-assembly driven by intermolecular interactions between monomers, and monomer structure determines the properties of the overall material. Using protein-based monomers takes advantage of the self-assembly and highly specific molecular recognition properties encodable in polypeptide sequences to rationally design SMP architectures. The central hypothesis underlying our work is that alpha-helical coiled coils, a well-studied protein quaternary folding motif, are well-suited to SMP design through the addition of synthetic linkers at solvent-exposed sites. Through small changes in the structures of the cross-links and/or peptide sequence, we have been able to control both the nanoscale organization and the macroscopic properties of the SMPs. Changes to the linker and hydrophobic core of the peptide can be used to control polymer rigidity, stability, and dimensionality. The gaps in knowledge that this thesis sought to fill on this project were 1) the relationship between the molecular structure of the cross-linked polypeptides and the macroscopic properties of the SMPs and 2) a means of creating materials exhibiting multi-dimensional net or framework topologies. Separate from the above efforts on supramolecular architectures was work on improving backbone modification strategies for an alpha-helix in the context of a complex protein tertiary fold. Earlier work in our lab had successfully incorporated unnatural building blocks into every major secondary structure (beta-sheet, alpha-helix, loops and beta

Accurate DNA assembly and genome engineering with optimized uracil excision cloning

DEFF Research Database (Denmark)

Cavaleiro, Mafalda; Kim, Se Hyeuk; Seppala, Susanna

2015-01-01

Simple and reliable DNA editing by uracil excision (a.k.a. USER cloning) has been described by several research groups, but the optimal design of cohesive DNA ends for multigene assembly remains elusive. Here, we use two model constructs based on expression of gfp and a four-gene pathway that pro......Simple and reliable DNA editing by uracil excision (a.k.a. USER cloning) has been described by several research groups, but the optimal design of cohesive DNA ends for multigene assembly remains elusive. Here, we use two model constructs based on expression of gfp and a four-gene pathway...... that produces β-carotene to optimize assembly junctions and the uracil excision protocol. By combining uracil excision cloning with a genomic integration technology, we demonstrate that up to six DNA fragments can be assembled in a one-tube reaction for direct genome integration with high accuracy, greatly...... facilitating the advanced engineering of robust cell factories....

CMV-Promoter Driven Codon-Optimized Expression Alters the Assembly Type and Morphology of a Reconstituted HERV-K(HML-2

Directory of Open Access Journals (Sweden)

Oliver Hohn

2014-11-01

Full Text Available The HERV-K(HML-2 family contains the most recently integrated and best preserved endogenized proviral sequences in the human genome. All known elements have nevertheless been subjected to mutations or deletions that render expressed particles non-infectious. Moreover, these post-insertional mutations hamper the analysis of the general biological properties of this ancient virus family. The expression of consensus sequences and sequences of elements with reverted post-insertional mutations has therefore been very instrumental in overcoming this limitation. We investigated the particle morphology of a recently reconstituted HERV-K113 element termed oriHERV-K113 using thin-section electron microscopy (EM and could demonstrate that strong overexpression by substitution of the 5'LTR for a CMV promoter and partial codon optimization altered the virus assembly type and morphology. This included a conversion from the regular C-type to an A-type morphology with a mass of cytoplasmic immature cores tethered to the cell membrane and the membranes of vesicles. Overexpression permitted the release and maturation of virions but reduced the envelope content. A weaker boost of virus expression by Staufen-1 was not sufficient to induce these morphological alterations.

CMV-promoter driven codon-optimized expression alters the assembly type and morphology of a reconstituted HERV-K(HML-2).

Science.gov (United States)

Hohn, Oliver; Hanke, Kirsten; Lausch, Veronika; Zimmermann, Anja; Mostafa, Saeed; Bannert, Norbert

2014-11-11

The HERV-K(HML-2) family contains the most recently integrated and best preserved endogenized proviral sequences in the human genome. All known elements have nevertheless been subjected to mutations or deletions that render expressed particles non-infectious. Moreover, these post-insertional mutations hamper the analysis of the general biological properties of this ancient virus family. The expression of consensus sequences and sequences of elements with reverted post-insertional mutations has therefore been very instrumental in overcoming this limitation. We investigated the particle morphology of a recently reconstituted HERV-K113 element termed oriHERV-K113 using thin-section electron microscopy (EM) and could demonstrate that strong overexpression by substitution of the 5'LTR for a CMV promoter and partial codon optimization altered the virus assembly type and morphology. This included a conversion from the regular C-type to an A-type morphology with a mass of cytoplasmic immature cores tethered to the cell membrane and the membranes of vesicles. Overexpression permitted the release and maturation of virions but reduced the envelope content. A weaker boost of virus expression by Staufen-1 was not sufficient to induce these morphological alterations.

Nitazoxanide Inhibits Pilus Biogenesis by Interfering with Folding of the Usher Protein in the Outer Membrane.

Science.gov (United States)

Chahales, Peter; Hoffman, Paul S; Thanassi, David G

2016-04-01

Many bacterial pathogens assemble surface fibers termed pili or fimbriae that facilitate attachment to host cells and colonization of host tissues. The chaperone/usher (CU) pathway is a conserved secretion system that is responsible for the assembly of virulence-associated pili by many different Gram-negative bacteria. Pilus biogenesis by the CU pathway requires a dedicated periplasmic chaperone and an integral outer membrane (OM) assembly and secretion platform termed the usher. Nitazoxanide (NTZ), an antiparasitic drug, was previously shown to inhibit the function of aggregative adherence fimbriae and type 1 pili assembled by the CU pathway in enteroaggregativeEscherichia coli, an important causative agent of diarrhea. We show here that NTZ also inhibits the function of type 1 and P pili from uropathogenicE. coli(UPEC). UPEC is the primary causative agent of urinary tract infections, and type 1 and P pili mediate colonization of the bladder and kidneys, respectively. By analysis of the different stages of the CU pilus biogenesis pathway, we show that treatment of bacteria with NTZ causes a reduction in the number of usher molecules in the OM, resulting in a loss of pilus assembly on the bacterial surface. In addition, we determine that NTZ specifically prevents proper folding of the usher β-barrel domain in the OM. Our findings demonstrate that NTZ is a pilicide with a novel mechanism of action and activity against diverse CU pathways. This suggests that further development of the NTZ scaffold may lead to new antivirulence agents that target the usher to prevent pilus assembly. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Daam1 regulates fascin for actin assembly in mouse oocyte meiosis.

Science.gov (United States)

Lu, Yujie; Zhang, Yu; Pan, Meng-Hao; Kim, Nam-Hyung; Sun, Shao-Chen; Cui, Xiang-Shun

2017-07-18

As a formin protein, Daam1 (Dishevelled-associated activator of morphogenesis 1) is reported to regulate series of cell processes like endocytosis, cell morphology and migration via its effects on actin assembly in mitosis. However, whether Daam1 plays roles in female meiosis remains uncertain. In this study, we investigated the expression and functions of Daam1 during mouse oocyte meiosis. Our results indicated that Daam1 localized at the cortex of oocytes, which was similar with actin filaments. After Daam1 morpholino (MO) microinjection, the expression of Daam1 significantly decreased, which resulted in the failure of oocyte polar body extrusion. These results might be due to the defects of actin assembly, since the decreased fluorescence intensity of actin filaments in oocyte cortex and cytoplasm were observed. However, Daam1 knockdown seemed not to affect the meiotic spindle movement. In addition, we found that fascin might be the down effector of Daam1, since the protein expression of fascin decreased after Daam1 knockdown. Thus, our data suggested that Daam1 affected actin assembly during oocyte meiotic division via the regulation of fascin expression.

Spin-Assisted Layer-by-Layer Assembly: Variation of Stratification as Studied with Neutron Reflectivity

International Nuclear Information System (INIS)

Kharlampieva, Eugenia; Kozlovskaya, Veronika; Chan, Jennifer; Ankner, John Francis; Tsukruk, Vladimir V.

2009-01-01

We apply neutron reflectivity to probe the internal structure of spin-assisted layer-by-layer (LbL) films composed of electrostatically assembled polyelectrolytes. We find that the level of stratification and the degree of layer intermixing can be controlled by varying the type and concentration of salt during LbL assembly. We observe well-defined layer structure in spin-assisted LbL films when deposited from salt-free solutions. These films feature 2-nm-thick bilayers, which are ∼3-fold thicker than those in dipped LbL films assembled under similar conditions. Addition of a 10mM phosphate buffer promotes progressive layer inter-diffusion with increasing distance from the substrate. However, adding 0.1M NaCl to the phosphate buffer solution restores the layer stratification. We also find that spin-assisted LbL films obtained from buffer solutions are more highly stratified as compared to the highly intermixed layers seen in dipped LbL films assembled from buffer. Our results yield new insight into the mechanism of spin-assisted LbL assembly that should prove useful for biotechnological applications.

NMR derived model of GTPase effector domain (GED self association: relevance to dynamin assembly.

Directory of Open Access Journals (Sweden)

Swagata Chakraborty

Full Text Available Self-association of dynamin to form spiral structures around lipidic vesicles during endocytosis is largely mediated by its 'coiled coil' GTPase Effector Domain (GED, which, in vitro, self-associates into huge helical assemblies. Residue-level structural characterizations of these assemblies and understanding the process of association have remained a challenge. It is also impossible to get folded monomers in the solution phase. In this context, we have developed here a strategy to probe the self-association of GED by first dissociating the assembly using Dimethyl Sulfoxide (DMSO and then systematically monitoring the refolding into helix and concomitant re-association using NMR spectroscopy, as DMSO concentration is progressively reduced. The short segment, Arg109 - Met116, acts as the nucleation site for helix formation and self-association. Hydrophobic and complementary charge interactions on the surfaces drive self-association, as the helices elongate in both the directions resulting in an antiparallel stack. A small N-terminal segment remains floppy in the assembly. Following these and other published results on inter-domain interactions, we have proposed a plausible mode of dynamin self assembly.

Ultrahigh PEMFC performance of a thin-film, dual-electrode assembly with tailored electrode morphology.

Science.gov (United States)

Jung, Chi-Young; Kim, Tae-Hyun; Yi, Sung-Chul

2014-02-01

A dual-electrode membrane electrode assembly (MEA) for proton exchange membrane fuel cells with enhanced polarization under zero relative humidity (RH) is fabricated by introducing a phase-separated morphology in an agglomerated catalyst layer of Pt/C (platinum on carbon black) and Nafion. In the catalyst layer, a sufficient level of phase separation is achieved by dispersing the Pt catalyst and the Nafion dispersion in a mixed-solvent system (propane-1,2,3-triol/1-methyl-2-pyrrolidinone).The high polymer chain mobility results in improved water uptake and regular pore-size distribution with small pore diameters. The electrochemical performance of the dual-film electrode assembly with different levels of phase separation is compared to conventional electrode assemblies. As a result, good performance at 0 % RH is obtained because self-humidification is dramatically improved by attaching this dense and phase-separated catalytic overlayer onto the conventional catalyst layer. A MEA prepared using the thin-film, dual-layered electrode exhibits 39-fold increased RH stability and 28-fold improved start-up recovery time during the on-off operation relative to the conventional device. We demonstrate the successful operation of the dual-layered electrode comprised of discriminatively phase-separated agglomerates with an ultrahigh zero RH fuel-cell performance reaching over 95 % performance of a fully humidified MEA. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

On the role of the chaperonin CCT in the just-in-time assembly process of APC/CCdc20.

Science.gov (United States)

Dekker, Carien

2010-02-05

The just-in-time hypothesis relates to the assembly of large multi-protein complexes and their regulation of activation in the cell. Here I postulate that chaperonins may contribute to the timely assembly and activation of such complexes. For the case of anaphase promoting complex/cyclosome(Cdc20) assembly by the eukaryotic chaperonin chaperonin containing Tcp1 it is shown that just-in-time synthesis and chaperone-assisted folding can synergise to generate a highly regulated assembly process of a protein complex that is vital for cell cycle progression. Once dependency has been established transcriptional regulation and chaperonin-dependency may have co-evolved to safeguard the timely activation of important multi-protein complexes. 2009 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

SAS-6 assembly templated by the lumen of cartwheel-less centrioles precedes centriole duplication.

Science.gov (United States)

Fong, Chii Shyang; Kim, Minhee; Yang, T Tony; Liao, Jung-Chi; Tsou, Meng-Fu Bryan

2014-07-28

Centrioles are 9-fold symmetric structures duplicating once per cell cycle. Duplication involves self-oligomerization of the centriolar protein SAS-6, but how the 9-fold symmetry is invariantly established remains unclear. Here, we found that SAS-6 assembly can be shaped by preexisting (or mother) centrioles. During S phase, SAS-6 molecules are first recruited to the proximal lumen of the mother centriole, adopting a cartwheel-like organization through interactions with the luminal wall, rather than via their self-oligomerization activity. The removal or release of luminal SAS-6 requires Plk4 and the cartwheel protein STIL. Abolishing either the recruitment or the removal of luminal SAS-6 hinders SAS-6 (or centriole) assembly at the outside wall of mother centrioles. After duplication, the lumen of engaged mother centrioles becomes inaccessible to SAS-6, correlating with a block for reduplication. These results lead to a proposed model that centrioles may duplicate via a template-based process to preserve their geometry and copy number. Copyright © 2014 Elsevier Inc. All rights reserved.

RNA-seq de novo Assembly Reveals Differential Gene Expression in Glossina palpalis gambiensis Infected with Trypanosoma brucei gambiense vs. Non-Infected and Self-Cured Flies.

Science.gov (United States)

Hamidou Soumana, Illiassou; Klopp, Christophe; Ravel, Sophie; Nabihoudine, Ibouniyamine; Tchicaya, Bernadette; Parrinello, Hugues; Abate, Luc; Rialle, Stéphanie; Geiger, Anne

2015-01-01

Trypanosoma brucei gambiense (Tbg), causing the sleeping sickness chronic form, completes its developmental cycle within the tsetse fly vector Glossina palpalis gambiensis (Gpg) before its transmission to humans. Within the framework of an anti-vector disease control strategy, a global gene expression profiling of trypanosome infected (susceptible), non-infected, and self-cured (refractory) tsetse flies was performed, on their midguts, to determine differential genes expression resulting from in vivo trypanosomes, tsetse flies (and their microbiome) interactions. An RNAseq de novo assembly was achieved. The assembled transcripts were mapped to reference sequences for functional annotation. Twenty-four percent of the 16,936 contigs could not be annotated, possibly representing untranslated mRNA regions, or Gpg- or Tbg-specific ORFs. The remaining contigs were classified into 65 functional groups. Only a few transposable elements were present in the Gpg midgut transcriptome, which may represent active transpositions and play regulatory roles. One thousand three hundred and seventy three genes differentially expressed (DEGs) between stimulated and non-stimulated flies were identified at day-3 post-feeding; 52 and 1025 between infected and self-cured flies at 10 and 20 days post-feeding, respectively. The possible roles of several DEGs regarding fly susceptibility and refractoriness are discussed. The results provide new means to decipher fly infection mechanisms, crucial to develop anti-vector control strategies.

SVM-Fold: a tool for discriminative multi-class protein fold and superfamily recognition.

Science.gov (United States)

Melvin, Iain; Ie, Eugene; Kuang, Rui; Weston, Jason; Stafford, William Noble; Leslie, Christina

2007-05-22

Predicting a protein's structural class from its amino acid sequence is a fundamental problem in computational biology. Much recent work has focused on developing new representations for protein sequences, called string kernels, for use with support vector machine (SVM) classifiers. However, while some of these approaches exhibit state-of-the-art performance at the binary protein classification problem, i.e. discriminating between a particular protein class and all other classes, few of these studies have addressed the real problem of multi-class superfamily or fold recognition. Moreover, there are only limited software tools and systems for SVM-based protein classification available to the bioinformatics community. We present a new multi-class SVM-based protein fold and superfamily recognition system and web server called SVM-Fold, which can be found at http://svm-fold.c2b2.columbia.edu. Our system uses an efficient implementation of a state-of-the-art string kernel for sequence profiles, called the profile kernel, where the underlying feature representation is a histogram of inexact matching k-mer frequencies. We also employ a novel machine learning approach to solve the difficult multi-class problem of classifying a sequence of amino acids into one of many known protein structural classes. Binary one-vs-the-rest SVM classifiers that are trained to recognize individual structural classes yield prediction scores that are not comparable, so that standard "one-vs-all" classification fails to perform well. Moreover, SVMs for classes at different levels of the protein structural hierarchy may make useful predictions, but one-vs-all does not try to combine these multiple predictions. To deal with these problems, our method learns relative weights between one-vs-the-rest classifiers and encodes information about the protein structural hierarchy for multi-class prediction. In large-scale benchmark results based on the SCOP database, our code weighting approach

Quantification of Porcine Vocal Fold Geometry.

Science.gov (United States)

Stevens, Kimberly A; Thomson, Scott L; Jetté, Marie E; Thibeault, Susan L

2016-07-01

The aim of this study was to quantify porcine vocal fold medial surface geometry and three-dimensional geometric distortion induced by freezing the larynx, especially in the region of the vocal folds. The medial surface geometries of five excised porcine larynges were quantified and reported. Five porcine larynges were imaged in a micro-CT scanner, frozen, and rescanned. Segmentations and three-dimensional reconstructions were used to quantify and characterize geometric features. Comparisons were made with geometry data previously obtained using canine and human vocal folds as well as geometries of selected synthetic vocal fold models. Freezing induced an overall expansion of approximately 5% in the transverse plane and comparable levels of nonuniform distortion in sagittal and coronal planes. The medial surface of the porcine vocal folds was found to compare reasonably well with other geometries, although the compared geometries exhibited a notable discrepancy with one set of published human female vocal fold geometry. Porcine vocal folds are qualitatively geometrically similar to data available for canine and human vocal folds, as well as commonly used models. Freezing of tissue in the larynx causes distortion of around 5%. The data can provide direction in estimating uncertainty due to bulk distortion of tissue caused by freezing, as well as quantitative geometric data that can be directly used in developing vocal fold models. Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Graph-representation of oxidative folding pathways

Directory of Open Access Journals (Sweden)

Kaján László

2005-01-01

Full Text Available Abstract Background The process of oxidative folding combines the formation of native disulfide bond with conformational folding resulting in the native three-dimensional fold. Oxidative folding pathways can be described in terms of disulfide intermediate species (DIS which can also be isolated and characterized. Each DIS corresponds to a family of folding states (conformations that the given DIS can adopt in three dimensions. Results The oxidative folding space can be represented as a network of DIS states interconnected by disulfide interchange reactions that can either create/abolish or rearrange disulfide bridges. We propose a simple 3D representation wherein the states having the same number of disulfide bridges are placed on separate planes. In this representation, the shuffling transitions are within the planes, and the redox edges connect adjacent planes. In a number of experimentally studied cases (bovine pancreatic trypsin inhibitor, insulin-like growth factor and epidermal growth factor, the observed intermediates appear as part of contiguous oxidative folding pathways. Conclusions Such networks can be used to visualize folding pathways in terms of the experimentally observed intermediates. A simple visualization template written for the Tulip package http://www.tulip-software.org/ can be obtained from V.A.

Understanding ensemble protein folding at atomic detail

International Nuclear Information System (INIS)

Wallin, Stefan; Shakhnovich, Eugene I

2008-01-01

Although far from routine, simulating the folding of specific short protein chains on the computer, at a detailed atomic level, is starting to become a reality. This remarkable progress, which has been made over the last decade or so, allows a fundamental aspect of the protein folding process to be addressed, namely its statistical nature. In order to make quantitative comparisons with experimental kinetic data a complete ensemble view of folding must be achieved, with key observables averaged over the large number of microscopically different folding trajectories available to a protein chain. Here we review recent advances in atomic-level protein folding simulations and the new insight provided by them into the protein folding process. An important element in understanding ensemble folding kinetics are methods for analyzing many separate folding trajectories, and we discuss techniques developed to condense the large amount of information contained in an ensemble of trajectories into a manageable picture of the folding process. (topical review)

Vocal fold injection medialization laryngoplasty.

Science.gov (United States)

Modi, Vikash K

2012-01-01

Unilateral vocal fold paralysis (UVFP) can cause glottic insufficiency that can result in hoarseness, chronic cough, dysphagia, and/or aspiration. In rare circumstances, UVFP can cause airway obstruction necessitating a tracheostomy. The treatment options for UVFP include observation, speech therapy, vocal fold injection medialization laryngoplasty, thyroplasty, and laryngeal reinnervation. In this chapter, the author will discuss the technique of vocal fold injection for medialization of a UVFP. Copyright © 2012 S. Karger AG, Basel.

Characterization of transcriptome dynamics during watermelon fruit development: sequencing, assembly, annotation and gene expression profiles.

Science.gov (United States)

Guo, Shaogui; Liu, Jingan; Zheng, Yi; Huang, Mingyun; Zhang, Haiying; Gong, Guoyi; He, Hongju; Ren, Yi; Zhong, Silin; Fei, Zhangjun; Xu, Yong

2011-09-21

Cultivated watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai var. lanatus] is an important agriculture crop world-wide. The fruit of watermelon undergoes distinct stages of development with dramatic changes in its size, color, sweetness, texture and aroma. In order to better understand the genetic and molecular basis of these changes and significantly expand the watermelon transcript catalog, we have selected four critical stages of watermelon fruit development and used Roche/454 next-generation sequencing technology to generate a large expressed sequence tag (EST) dataset and a comprehensive transcriptome profile for watermelon fruit flesh tissues. We performed half Roche/454 GS-FLX run for each of the four watermelon fruit developmental stages (immature white, white-pink flesh, red flesh and over-ripe) and obtained 577,023 high quality ESTs with an average length of 302.8 bp. De novo assembly of these ESTs together with 11,786 watermelon ESTs collected from GenBank produced 75,068 unigenes with a total length of approximately 31.8 Mb. Overall 54.9% of the unigenes showed significant similarities to known sequences in GenBank non-redundant (nr) protein database and around two-thirds of them matched proteins of cucumber, the most closely-related species with a sequenced genome. The unigenes were further assigned with gene ontology (GO) terms and mapped to biochemical pathways. More than 5,000 SSRs were identified from the EST collection. Furthermore we carried out digital gene expression analysis of these ESTs and identified 3,023 genes that were differentially expressed during watermelon fruit development and ripening, which provided novel insights into watermelon fruit biology and a comprehensive resource of candidate genes for future functional analysis. We then generated profiles of several interesting metabolites that are important to fruit quality including pigmentation and sweetness. Integrative analysis of metabolite and digital gene expression

N-linked glycans are required on epithelial Na+ channel subunits for maturation and surface expression.

Science.gov (United States)

Kashlan, Ossama B; Kinlough, Carol L; Myerburg, Michael M; Shi, Shujie; Chen, Jingxin; Blobner, Brandon M; Buck, Teresa M; Brodsky, Jeffrey L; Hughey, Rebecca P; Kleyman, Thomas R

2018-03-01

Epithelial Na + channel (ENaC) subunits undergo N-linked glycosylation in the endoplasmic reticulum where they assemble into an αβγ complex. Six, 13, and 5 consensus sites (Asn-X-Ser/Thr) for N-glycosylation reside in the extracellular domains of the mouse α-, β-, and γ-subunits, respectively. Because the importance of ENaC N-linked glycans has not been fully addressed, we examined the effect of preventing N-glycosylation of specific subunits on channel function, expression, maturation, and folding. Heterologous expression in Xenopus oocytes or Fischer rat thyroid cells with αβγ-ENaC lacking N-linked glycans on a single subunit reduced ENaC activity as well as the inhibitory response to extracellular Na + . The lack of N-linked glycans on the β-subunit also precluded channel activation by trypsin. However, channel activation by shear stress was N-linked glycan independent, regardless of which subunit was modified. We also discovered that the lack of N-linked glycans on any one subunit reduced the total and surface levels of cognate subunits. The lack of N-linked glycans on the β-subunit had the largest effect on total levels, with the lack of N-linked glycans on the γ- and α-subunits having intermediate and modest effects, respectively. Finally, channels with wild-type β-subunits were more sensitive to limited trypsin proteolysis than channels lacking N-linked glycans on the β-subunit. Our results indicate that N-linked glycans on each subunit are required for proper folding, maturation, surface expression, and function of the channel.

A consensus approach to vertebrate de novo transcriptome assembly from RNA-seq data: Assembly of the duck (Anas platyrhynchos transcriptome.

Directory of Open Access Journals (Sweden)

Joanna eMoreton

2014-06-01

Full Text Available For vertebrate organisms where a reference genome is not available, de novo transcriptome assembly enables a cost effective insight into the identification of tissue specific or differentially expressed genes and variation of the coding part of the genome. However, since there are a number of different tools and parameters that can be used to reconstruct transcripts, it is difficult to determine an optimal method. Here we suggest a pipeline based on (1 assessing the performance of three different assembly tools (2 using both single and multiple k-mer approaches (3 examining the influence of the number of reads used in the assembly (4 merging assemblies from different tools. We use an example dataset from the vertebrate Anas platyrhynchos domestica (Pekin duck. We find that taking a subset of data enables a robust assembly to be produced by multiple methods without the need for very high memory capacity. The use of reads mapped back to transcripts (RMBT and CEGMA (Core Eukaryotic Genes Mapping Approach provides useful metrics to determine the completeness of assembly obtained. For this dataset the use of multiple k-mers in the assembly generated a more complete assembly as measured by greater number of RMBT and CEGMA score. Merged single k-mer assemblies are generally smaller but consist of longer transcripts, suggesting an assembly consisting of fewer fragmented transcripts. We suggest that the use of a subset of reads during assembly allows the relatively rapid investigation of assembly characteristics and can guide the user to the most appropriate transcriptome for particular downstream use. Transcriptomes generated by the compared assembly methods and the final merged assembly are freely available for download at http://dx.doi.org/10.6084/m9.figshare.1032613.

Functional results after external vocal fold medialization thyroplasty with the titanium vocal fold medialization implant.

Science.gov (United States)

Schneider, Berit; Denk, Doris-Maria; Bigenzahn, Wolfgang

2003-04-01

A persistent insufficiency of glottal closure is mostly a consequence of a unilateral vocal fold movement impairment. It can also be caused by vocal fold atrophy or scarring processes with regular bilateral respiratory vocal fold function. Because of consequential voice, breathing, and swallowing impairments, a functional surgical treatment is required. The goal of the study was to outline the functional results after medialization thyroplasty with the titanium vocal fold medialization implant according to Friedrich. In the period of 1999 to 2001, an external vocal fold medialization using the titanium implant was performed on 28 patients (12 women and 16 men). The patients were in the age range of 19 to 84 years. Twenty-two patients had a paralysis of the left-side vocal fold, and six patients, of the right-side vocal fold. Detailed functional examinations were executed on all patients before and after the surgery: perceptive voice sound analysis according to the "roughness, breathiness, and hoarseness" method, judgment of the s/z ratio and voice dysfunction index, voice range profile measurements, videostroboscopy, and pulmonary function tests. In case of dysphagia/aspiration, videofluoroscopy of swallowing was also performed. The respective data were statistically analyzed (paired t test, Wilcoxon-test). All patients reported on improvement of voice, swallowing, and breathing functions postoperatively. Videostroboscopy revealed an almost complete glottal closure after surgery in all of the patients. All voice-related parameters showed a significant improvement. An increase of the laryngeal resistance by the medialization procedure could be excluded by analysis of the pulmonary function test. The results confirm the external medialization of the vocal folds as an adequate method in the therapy of voice, swallowing, and breathing impairment attributable to an insufficient glottal closure. The titanium implant offers, apart from good tissue tolerability, the

The hominoid-specific gene TBC1D3 promotes generation of basal neural progenitors and induces cortical folding in mice

Science.gov (United States)

Ju, Xiang-Chun; Hou, Qiong-Qiong; Sheng, Ai-Li; Wu, Kong-Yan; Zhou, Yang; Jin, Ying; Wen, Tieqiao; Yang, Zhengang; Wang, Xiaoqun; Luo, Zhen-Ge

2016-01-01

Cortical expansion and folding are often linked to the evolution of higher intelligence, but molecular and cellular mechanisms underlying cortical folding remain poorly understood. The hominoid-specific gene TBC1D3 undergoes segmental duplications during hominoid evolution, but its role in brain development has not been explored. Here, we found that expression of TBC1D3 in ventricular cortical progenitors of mice via in utero electroporation caused delamination of ventricular radial glia cells (vRGs) and promoted generation of self-renewing basal progenitors with typical morphology of outer radial glia (oRG), which are most abundant in primates. Furthermore, down-regulation of TBC1D3 in cultured human brain slices decreased generation of oRGs. Interestingly, localized oRG proliferation resulting from either in utero electroporation or transgenic expression of TBC1D3, was often found to underlie cortical regions exhibiting folding. Thus, we have identified a hominoid gene that is required for oRG generation in regulating the cortical expansion and folding. DOI: http://dx.doi.org/10.7554/eLife.18197.001 PMID:27504805

Can specific transcriptional regulators assemble a universal cancer signature?

Science.gov (United States)

Roy, Janine; Isik, Zerrin; Pilarsky, Christian; Schroeder, Michael

2013-10-01

Recently, there is a lot of interest in using biomarker signatures derived from gene expression data to predict cancer progression. We assembled signatures of 25 published datasets covering 13 types of cancers. How do these signatures compare with each other? On one hand signatures answering the same biological question should overlap, whereas signatures predicting different cancer types should differ. On the other hand, there could also be a Universal Cancer Signature that is predictive independently of the cancer type. Initially, we generate signatures for all datasets using classical approaches such as t-test and fold change and then, we explore signatures resulting from a network-based method, that applies the random surfer model of Google's PageRank algorithm. We show that the signatures as published by the authors and the signatures generated with classical methods do not overlap - not even for the same cancer type - whereas the network-based signatures strongly overlap. Selecting 10 out of 37 universal cancer genes gives the optimal prediction for all cancers thus taking a first step towards a Universal Cancer Signature. We furthermore analyze and discuss the involved genes in terms of the Hallmarks of cancer and in particular single out SP1, JUN/FOS and NFKB1 and examine their specific role in cancer progression.

RNA-seq methods for identifying differentially expressed gene in human pancreatic islet cells treated with pro-inflammatory cytokines.

Science.gov (United States)

Li, Bo; Bi, Chang Long; Lang, Ning; Li, Yu Ze; Xu, Chao; Zhang, Ying Qi; Zhai, Ai Xia; Cheng, Zhi Feng

2014-01-01

Type 1 diabetes is a chronic autoimmune disease in which pancreatic beta cells are killed by the infiltrating immune cells as well as the cytokines released by these cells. Many studies indicate that inflammatory mediators have an essential role in this disease. In the present study, we profiled the transcriptome in human islets of langerhans under control conditions or following exposure to the pro-inflammatory cytokines based on the RNA sequencing dataset downloaded from SRA database. After filtered the low-quality ones, the RNA readers was aligned to human genome hg19 by TopHat and then assembled by Cufflinks. The expression value of each transcript was calculated and consequently differentially expressed genes were screened out. Finally, a total of 63 differentially expressed genes were identified including 60 up-regulated and three down-regulated genes. GBP5 and CXCL9 stood out as the top two most up-regulated genes in cytokines treated samples with the log2 fold change of 12.208 and 10.901, respectively. Meanwhile, PTF1A and REG3G were identified as the top two most down-regulated genes with the log2 fold change of -3.759 and -3.606, respectively. Of note, we also found 262 lncRNAs (long non-coding RNA), 177 of which were inferred as novel lncRNAs. Further in-depth follow-up analysis of the transcriptional regulation reported in this study may shed light on the specific function of these lncRNA.

Fluidic origami cellular structure -- combining the plant nastic movements with paper folding art

Science.gov (United States)

Li, Suyi; Wang, K. W.

2015-04-01

By combining the physical principles behind the nastic plant movements and the rich designs of paper folding art, we propose a new class of multi-functional adaptive structure called fluidic origami cellular structure. The basic elements of this structure are fluid filled origami "cells", made by connecting two compatible Miura-Ori stripes along their crease lines. These cells are assembled seamlessly into a three dimensional topology, and their internal fluid pressure or volume are strategically controlled just like in plants for nastic movements. Because of the unique geometry of the Miura-Ori, the relationships among origami folding, internal fluid properties, and the crease bending are intricate and highly nonlinear. Fluidic origami can exploit such relationships to provide multiple adaptive functions concurrently and effectively. For example, it can achieve actuation or morphing by actively changing the internal fluid volume, and stillness tuning by constraining the fluid volume. Fluidic origami can also be bistable because of the nonlinear correlation between folding and crease material bending, and such bistable character can be altered significantly by fluid pressurization. These functions are natural and essential companions with respect to each other, so that fluidic origami can holistically exhibit many attractive characteristics of plants and deliver rapid and efficient actuation/morphing while maintaining a high structural stillness. The purpose of this paper is to introduce the design and working principles of the fluidic origami, as well as to explore and demonstrate its performance potential.

The nucleosome assembly activity of NAP1 is enhanced by Alien.

Science.gov (United States)

Eckey, Maren; Hong, Wei; Papaioannou, Maria; Baniahmad, Aria

2007-05-01

The assembly of nucleosomes into chromatin is essential for the compaction of DNA and inactivation of the DNA template to modulate and repress gene expression. The nucleosome assembly protein 1, NAP1, assembles nucleosomes independent of DNA synthesis and was shown to enhance coactivator-mediated gene expression, suggesting a role for NAP1 in transcriptional regulation. Here, we show that Alien, known to harbor characteristics of a corepressor of nuclear hormone receptors such as of the vitamin D receptor (VDR), binds in vivo and in vitro to NAP1 and modulates its activity by enhancing NAP1-mediated nucleosome assembly on DNA. Furthermore, Alien reduces the accessibility of the histones H3 and H4 for NAP1-promoted assembly reaction. This indicates that Alien sustains and reinforces the formation of nucleosomes. Employing deletion mutants of Alien suggests that different regions of Alien are involved in enhancement of NAP1-mediated nucleosome assembly and in inhibiting the accessibility of the histones H3 and H4. In addition, we provide evidence that Alien is associated with chromatin and with micrococcus nuclease-prepared nucleosome fractions and interacts with the histones H3 and H4. Furthermore, chromatin immunoprecipitation and reimmunoprecipitation experiments suggest that NAP1 and Alien localize to the endogenous CYP24 promoter in vivo, a VDR target gene. Based on these findings, we present here a novel pathway linking corepressor function with nucleosome assembly activity.

A comparison of RNA folding measures

Directory of Open Access Journals (Sweden)

Gardner Paul P

2005-10-01

Full Text Available Abstract Background In the last few decades there has been a great deal of discussion concerning whether or not noncoding RNA sequences (ncRNAs fold in a more well-defined manner than random sequences. In this paper, we investigate several existing measures for how well an RNA sequence folds, and compare the behaviour of these measures over a large range of Rfam ncRNA families. Such measures can be useful in, for example, identifying novel ncRNAs, and indicating the presence of alternate RNA foldings. Results Our analysis shows that ncRNAs, but not mRNAs, in general have lower minimal free energy (MFE than random sequences with the same dinucleotide frequency. Moreover, even when the MFE is significant, many ncRNAs appear to not have a unique fold, but rather several alternative folds, at least when folded in silico. Furthermore, we find that the six investigated measures are correlated to varying degrees. Conclusion Due to the correlations between the different measures we find that it is sufficient to use only two of them in RNA folding studies, one to test if the sequence in question has lower energy than a random sequence with the same dinucleotide frequency (the Z-score and the other to see if the sequence has a unique fold (the average base-pair distance, D.

One-step self-assembled nanomicelles for improving the oral bioavailability of nimodipine

Directory of Open Access Journals (Sweden)

Luo JW

2016-03-01

Full Text Available Jing-Wen Luo, Zhi-Rong Zhang, Tao Gong, Yao Fu Key Laboratory of Drug Targeting and Drug Delivery Systems, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, People’s Republic of China Abstract: Our study aimed to develop a self-assembled nanomicelle for oral administration of nimodipine (NIM with poor water solubility. Using Solutol® HS15, the NIM-loaded self-assembled nanomicelles displayed a near-spherical morphology with a narrow size distribution of 12.57±0.21 nm (polydispersity index =0.071±0.011. Compared with Nimotop® (NIM tablets, the intestinal absorption of NIM from NIM nanomicelle in rats was improved by 3.13- and 2.25-fold in duodenum and jejunum at 1 hour after oral administration. The cellular transport of NIM nanomicelle in Caco-2 cell monolayers was significantly enhanced compared to that of Nimotop®. Regarding the transport pathways, clathrin, lipid raft/caveolae, and macropinocytosis mediated the cell uptake of NIM nanomicelles, while P-glycoprotein and endoplasmic reticulum/Golgi complex (ER/Golgi pathways were involved in exocytosis. Pharmacokinetic studies in our research laboratory have showed that the area under the plasma concentration–time curve (AUC0–∞ of NIM nanomicelles was 3.72-fold that of Nimotop® via oral administration in rats. Moreover, the NIM concentration in the brain from NIM nanomicelles was dramatically improved. Therefore, Solutol® HS15-based self-assembled nanomicelles represent a promising delivery system to enhance the oral bioavailability of NIM. Keywords: nanomicelles, stability, nimodipine, oral bioavailability, transport mechanism 

RNAiFold: a web server for RNA inverse folding and molecular design.

Science.gov (United States)

Garcia-Martin, Juan Antonio; Clote, Peter; Dotu, Ivan

2013-07-01

Synthetic biology and nanotechnology are poised to make revolutionary contributions to the 21st century. In this article, we describe a new web server to support in silico RNA molecular design. Given an input target RNA secondary structure, together with optional constraints, such as requiring GC-content to lie within a certain range, requiring the number of strong (GC), weak (AU) and wobble (GU) base pairs to lie in a certain range, the RNAiFold web server determines one or more RNA sequences, whose minimum free-energy secondary structure is the target structure. RNAiFold provides access to two servers: RNA-CPdesign, which applies constraint programming, and RNA-LNSdesign, which applies the large neighborhood search heuristic; hence, it is suitable for larger input structures. Both servers can also solve the RNA inverse hybridization problem, i.e. given a representation of the desired hybridization structure, RNAiFold returns two sequences, whose minimum free-energy hybridization is the input target structure. The web server is publicly accessible at http://bioinformatics.bc.edu/clotelab/RNAiFold, which provides access to two specialized servers: RNA-CPdesign and RNA-LNSdesign. Source code for the underlying algorithms, implemented in COMET and supported on linux, can be downloaded at the server website.

FOLDNA, a Web Server for Self-Assembled DNA Nanostructure Autoscaffolds and Autostaples

Directory of Open Access Journals (Sweden)

Chensheng Zhou

2012-01-01

Full Text Available DNA self-assembly is a nanotechnology that folds DNA into desired shapes. Self-assembled DNA nanostructures, also known as origami, are increasingly valuable in nanomaterial and biosensing applications. Two ways to use DNA nanostructures in medicine are to form nanoarrays, and to work as vehicles in drug delivery. The DNA nanostructures perform well as a biomaterial in these areas because they have spatially addressable and size controllable properties. However, manually designing complementary DNA sequences for self-assembly is a technically demanding and time consuming task, which makes it advantageous for computers to do this job instead. We have developed a web server, FOLDNA, which can automatically design 2D self-assembled DNA nanostructures according to custom pictures and scaffold sequences provided by the users. It is the first web server to provide an entirely automatic design of self-assembled DNA nanostructure, and it takes merely a second to generate comprehensive information for molecular experiments including: scaffold DNA pathways, staple DNA directions, and staple DNA sequences. This program could save as much as several hours in the designing step for each DNA nanostructure. We randomly selected some shapes and corresponding outputs from our server and validated its performance in molecular experiments.

Repairing the vibratory vocal fold.

Science.gov (United States)

Long, Jennifer L

2018-01-01

A vibratory vocal fold replacement would introduce a new treatment paradigm for structural vocal fold diseases such as scarring and lamina propria loss. This work implants a tissue-engineered replacement for vocal fold lamina propria and epithelium in rabbits and compares histology and function to injured controls and orthotopic transplants. Hypotheses were that the cell-based implant would engraft and control the wound response, reducing fibrosis and restoring vibration. Translational research. Rabbit adipose-derived mesenchymal stem cells (ASC) were embedded within a three-dimensional fibrin gel, forming the cell-based outer vocal fold replacement (COVR). Sixteen rabbits underwent unilateral resection of vocal fold epithelium and lamina propria, as well as reconstruction with one of three treatments: fibrin glue alone with healing by secondary intention, replantation of autologous resected vocal fold cover, or COVR implantation. After 4 weeks, larynges were examined histologically and with phonation. Fifteen rabbits survived. All tissues incorporated well after implantation. After 1 month, both graft types improved histology and vibration relative to injured controls. Extracellular matrix (ECM) of the replanted mucosa was disrupted, and ECM of the COVR implants remained immature. Immune reaction was evident when male cells were implanted into female rabbits. Best histologic and short-term vibratory outcomes were achieved with COVR implants containing male cells implanted into male rabbits. Vocal fold cover replacement with a stem cell-based tissue-engineered construct is feasible and beneficial in acute rabbit implantation. Wound-modifying behavior of the COVR implant is judged to be an important factor in preventing fibrosis. NA. Laryngoscope, 128:153-159, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Human Cytomegalovirus Exploits Interferon-Induced Transmembrane Proteins To Facilitate Morphogenesis of the Virion Assembly Compartment

Science.gov (United States)

Xie, Maorong; Xuan, Baoqin; Shan, Jiaoyu; Pan, Deng; Sun, Yamei; Shan, Zhao; Zhang, Jinping; Yu, Dong

2014-01-01

ABSTRACT Recently, interferon-induced transmembrane proteins (IFITMs) have been identified to be key effector molecules in the host type I interferon defense system. The invasion of host cells by a large range of RNA viruses is inhibited by IFITMs during the entry step. However, the roles of IFITMs in DNA virus infections have not been studied in detail. In this study, we report that human cytomegalovirus (HCMV), a large human DNA virus, exploits IFITMs to facilitate the formation of the virion assembly compartment (vAC) during infection of human fibroblasts. We found that IFITMs were expressed constitutively in human embryonic lung fibroblasts (MRC5 cells). HCMV infection inhibited IFITM protein accumulation in the later stages of infection. Overexpression of an IFITM protein in MRC5 cells slightly enhanced HCMV production and knockdown of IFITMs by RNA interference reduced the virus titer by about 100-fold on day 8 postinfection, according to the findings of a virus yield assay at a low multiplicity of infection. Virus gene expression and DNA synthesis were not affected, but the typical round structure of the vAC was not formed after the suppression of IFITMs, thereby resulting in defective virion assembly and the production of less infectious virion particles. Interestingly, the replication of herpes simplex virus, a human herpesvirus that is closely related to HCMV, was not affected by the suppression of IFITMs in MRC5 cells. These results indicate that IFITMs are involved in a specific pathway required for HCMV replication. IMPORTANCE HCMV is known to repurpose the interferon-stimulated genes (ISGs) viperin and tetherin to facilitate its replication. Our results expand the range of ISGs that can be exploited by HCMV for its replication. This is also the first report of a proviral function of IFITMs in DNA virus replication. In addition, whereas previous studies showed that IFITMs modulate virus entry, which is a very early stage in the virus life cycle, we

Kinetic partitioning mechanism of HDV ribozyme folding

Energy Technology Data Exchange (ETDEWEB)

Chen, Jiawen; Gong, Sha; Wang, Yujie; Zhang, Wenbing, E-mail: wbzhang@whu.edu.cn [Department of Physics, Wuhan University, Wuhan, Hubei 430072 (China)

2014-01-14

RNA folding kinetics is directly tied to RNA biological functions. We introduce here a new approach for predicting the folding kinetics of RNA secondary structure with pseudoknots. This approach is based on our previous established helix-based method for predicting the folding kinetics of RNA secondary structure. In this approach, the transition rates for an elementary step: (1) formation, (2) disruption of a helix stem, and (3) helix formation with concomitant partial melting of an incompatible helix, are calculated with the free energy landscape. The folding kinetics of the Hepatitis delta virus (HDV) ribozyme and the mutated sequences are studied with this method. The folding pathways are identified by recursive searching the states with high net flux-in(out) population starting from the native state. The theory results are in good agreement with that of the experiments. The results indicate that the bi-phasic folding kinetics for the wt HDV sequence is ascribed to the kinetic partitioning mechanism: Part of the population will quickly fold to the native state along the fast pathway, while another part of the population will fold along the slow pathway, in which the population is trapped in a non-native state. Single mutation not only changes the folding rate but also the folding pathway.

Chemical chaperones exceed the chaperone effects of RIC-3 in promoting assembly of functional α7 AChRs.

Directory of Open Access Journals (Sweden)

Alexander Kuryatov

Full Text Available Functional α7 nicotinic acetylcholine receptors (AChRs do not assemble efficiently in cells transfected with α7 subunits unless the cells are also transfected with the chaperone protein RIC-3. Despite the presence of RIC-3, large amounts of these subunits remain improperly assembled. Thus, additional chaperone proteins are probably required for efficient assembly of α7 AChRs. Cholinergic ligands can act as pharmacological chaperones to promote assembly of mature AChRs and upregulate the amount of functional AChRs. In addition, we have found that the chemical chaperones 4-phenylbutyric acid (PBA and valproic acid (VPA greatly increase the amount of functional α7 AChRs produced in a cell line expressing both α7 and RIC-3. Increased α7 AChR expression allows assay of drug action using a membrane potential-sensitive fluorescent indicator. Both PBA and VPA also increase α7 expression in the SH-SY5Y neuroblastoma cell line that endogenously expresses α7 AChRs. VPA increases expression of endogenous α7 AChRs in hippocampal neurons but PBA does not. RIC-3 is insufficient for optimal assembly of α7 AChRs, but provides assay conditions for detecting additional chaperones. Chemical chaperones are a useful pragmatic approach to express high levels of human α7 AChRs for drug selection and characterization and possibly to increase α7 expression in vivo.

Self-folding origami at any energy scale

Science.gov (United States)

Pinson, Matthew B.; Stern, Menachem; Carruthers Ferrero, Alexandra; Witten, Thomas A.; Chen, Elizabeth; Murugan, Arvind

2017-05-01

Programmable stiff sheets with a single low-energy folding motion have been sought in fields ranging from the ancient art of origami to modern meta-materials research. Despite such attention, only two extreme classes of crease patterns are usually studied; special Miura-Ori-based zero-energy patterns, in which crease folding requires no sheet bending, and random patterns with high-energy folding, in which the sheet bends as much as creases fold. We present a physical approach that allows systematic exploration of the entire space of crease patterns as a function of the folding energy. Consequently, we uncover statistical results in origami, finding the entropy of crease patterns of given folding energy. Notably, we identify three classes of Mountain-Valley choices that have widely varying `typical' folding energies. Our work opens up a wealth of experimentally relevant self-folding origami designs not reliant on Miura-Ori, the Kawasaki condition or any special symmetry in space.

Anatomy and Histology of an Epicanthal Fold.

Science.gov (United States)

Park, Jae Woo; Hwang, Kun

2016-06-01

The aim of this study is to elucidate the precise anatomical and histological detail of the epicanthal fold.Thirty-two hemifaces of 16 Korean adult cadavers were used in this study (30 hemifaces with an epicanthal fold, 2 without an epicanthal fold). In 2 patients who had an epicanthoplasty, the epicanthal folds were sampled.In a dissection, the periorbital skin and subcutaneous tissues were removed and the epicanthal fold was observed in relation to each part of the orbicularis oculi muscle. Specimens including the epicanthal fold were embeddedin in paraffin, sectioned at 10 um, and stained with Hematoxylin-Eosin. The horizontal section in the level of the paplebral fissure was made and the prepared slides were observed under a light microscope.In the specimens without an epicanthal fold, no connection between the upper preseptal muscle and the lower preseptal muscle was found. In the specimens with an epicanthal fold, a connection of the upper preseptal muscle to the lower preseptal muscle was observed. It was present in all 15 hemifaces (100%). There was no connection between the pretarsal muscles. In a horizontal section, the epicanthal fold was composed of 3 compartments: an outer skin lining, a core structure, and an innerskin lining. The core structure was mainly composed of muscular fibers and fibrotic tissue and they were intermingled.Surgeons should be aware of the anatomical details of an epicanthal fold. In removing or reconstructing an epicanthal fold, the fibromuscular core band should also be removed or reconstructed.

The review on tessellation origami inspired folded structure

Science.gov (United States)

Chu, Chai Chen; Keong, Choong Kok

2017-10-01

Existence of folds enhances the load carrying capacity of a folded structure which makes it suitable to be used for application where large open space is required such as large span roof structures and façade. Folded structure is closely related to origami especially the tessellation origami. Tessellation origami provides a folded configuration with facetted surface as a result from repeated folding pattern. Besides that, tessellation origami has flexible folding mechanism that produced a variety of 3-dimensional folded configurations. Despite the direct relationship between fold in origami and folded structure, the idea of origami inspired folded structure is not properly reviewed in the relevant engineering field. Hence, this paper aims to present the current studies from related discipline which has direct relation with application of tessellation origami in folded structure. First, tessellation origami is properly introduced and defined. Then, the review covers the topic on the origami tessellation design suitable for folded structure, its modeling and simulation method, and existing studies and applications of origami as folded structure is presented. The paper also includes the discussion on the current issues related to each topic.

Self-assembled liquid crystalline nanoparticles as a novel ophthalmic delivery system for dexamethasone: Improving preocular retention and ocular bioavailability.

Science.gov (United States)

Gan, Li; Han, Shun; Shen, Jinqiu; Zhu, Jiabi; Zhu, Chunliu; Zhang, Xinxin; Gan, Yong

2010-08-30

The object of this study was to design novel self-assembled liquid crystalline nanoparticles (cubosomes) as an ophthalmic delivery system for dexamethasone (DEX) to improve its preocular retention and ocular bioavailability. DEX cubosome particles were produced by fragmenting a cubic crystalline phase of monoolein and water in the presence of stabilizer Poloxamer 407. Small angle X-ray diffraction (SAXR) profiles revealed its internal structure as Pn3m space group, indicating the diamond cubic phase. In vitro, the apparent permeability coefficient of DEX administered in cubosomes exhibited a 4.5-fold (F1) and 3.5-fold (F2) increase compared to that of Dex-Na phosphate eye drops. Preocular retention studies revealed that the retention of cubosomes was significantly longer than that of solution and carbopol gel, with AUC(0-->180min) of Rh B cubosomes being 2-3-fold higher than that of the other two formulations. In vivo pharmacokinetics in aqueous humor was evaluated by microdialysis, which indicated a 1.8-fold (F1) increase in AUC(0-->240min) of DEX administered in cubosomes relative to that of Dex-Na phosphate eye drops, with about an 8-fold increase compared to that of DEX suspension. Corneal cross-sections after incubation with DEX cubosomes demonstrated an unaffected corneal structure and tissue integrity, which indicated the good biocompatibility of DEX cubosomes. In conclusion, self-assembled liquid crystalline nanoparticles might represent a promising vehicle for effective ocular drug delivery. Crown Copyright 2010. Published by Elsevier B.V. All rights reserved.

Treatment planning capability assessment of a beam shaping assembly for accelerator-based BNCT

International Nuclear Information System (INIS)

Herrera, M.S.; González, S.J.; Burlon, A.A.; Minsky, D.M.; Kreiner, A.J.

2011-01-01

Within the frame of an ongoing project to develop a folded Tandem-Electrostatic-Quadrupole accelerator facility for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT) a theoretical study was performed to assess the treatment planning capability of different configurations of an optimized beam shaping assembly for such a facility. In particular this study aims at evaluating treatment plans for a clinical case of Glioblastoma.

A Portrait of Ribosomal DNA Contacts with Hi-C Reveals 5S and 45S rDNA Anchoring Points in the Folded Human Genome.

Science.gov (United States)

Yu, Shoukai; Lemos, Bernardo

2016-12-31

Ribosomal RNAs (rRNAs) account for >60% of all RNAs in eukaryotic cells and are encoded in the ribosomal DNA (rDNA) arrays. The rRNAs are produced from two sets of loci: the 5S rDNA array resides exclusively on human chromosome 1, whereas the 45S rDNA array resides on the short arm of five human acrocentric chromosomes. The 45S rDNA gives origin to the nucleolus, the nuclear organelle that is the site of ribosome biogenesis. Intriguingly, 5S and 45S rDNA arrays exhibit correlated copy number variation in lymphoblastoid cells (LCLs). Here we examined the genomic architecture and repeat content of the 5S and 45S rDNA arrays in multiple human genome assemblies (including PacBio MHAP assembly) and ascertained contacts between the rDNA arrays and the rest of the genome using Hi-C datasets from two human cell lines (erythroleukemia K562 and lymphoblastoid cells). Our analyses revealed that 5S and 45S arrays each have thousands of contacts in the folded genome, with rDNA-associated regions and genes dispersed across all chromosomes. The rDNA contact map displayed conserved and disparate features between two cell lines, and pointed to specific chromosomes, genomic regions, and genes with evidence of spatial proximity to the rDNA arrays; the data also showed a lack of direct physical interaction between the 5S and 45S rDNA arrays. Finally, the analysis identified an intriguing organization in the 5S array with Alu and 5S elements adjacent to one another and organized in opposite orientation along the array. Portraits of genome folding centered on the ribosomal DNA array could help understand the emergence of concerted variation, the control of 5S and 45S expression, as well as provide insights into an organelle that contributes to the spatial localization of human chromosomes during interphase. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Positive therapy of andrographolide in vocal fold leukoplakia.

Science.gov (United States)

Xu, Jue; Xue, Tao; Bao, Ying; Wang, Dong-Hai; Ma, Bing-Liang; Yin, Chen-Yi; Yang, Guang-Hui; Ren, Gang; Lan, Long-Jiang; Wang, Jian-Qiu; Zhang, Xiao-Lan; Zhao, Yu-Qin

2014-01-01

Vocal fold leukoplakia is a premalignant precursor of squamous cell carcinoma. Although many efforts have been contributed to therapy of this disease, none exhibits a satisfactory result. The aims of this study were to investigate the effectiveness and feasibility of andrographolide therapy in vocal fold leukoplakia and to explore the preliminary mechanism underlying. Forty-one eligible patients were enrolled in the study. The patients were treated for 10-minute exposures of 5 ml (25mg/ml) andrographolide injection aerosols twice a day, and 2 weeks was considered as one treatment course. Electronic laryngoscope was used to observe the condition of vocal fold leukoplakia during the treatment. Every patient received one or two treatment courses, and the follow-up was carried out for 12 months. Toxic reactions of treatments were evaluated on the basis of the standards of the United States MD Anderson Cancer Center. Moreover, laryngeal carcinoma cell line Hep2 was applied to explore the mechanism of effect of andrographolide. Anti-proliferative effect on Hep2, cell nuclear morphology, express of mitogen-activated protein kinases (MAPK) and pro-apoptotic protein were detected after andrographolide treatment. We found that andrographolide exhibited significant curative effects on treatments, which were accompanied by thinning of the lesion of leukoplakia, reduction in the whitish surface area, and return of pink or red epithelium. A complete response up to 85% was observed, and no toxic side effect events occurred during the study. No patient with a complete response had a recurrence in the follow-up. Moreover, cellular experiments in Hep2 indicated that andrographolide activated MAPK pathway and caspase cascade, and finally induced apoptosis in laryngeal carcinoma cell. The advantages of andrographolide are connected with minimally invasive and localized character of the treatment and no damage of collagenous tissue structures, which are more convenient and less painful

The Ability of Human Nasal Inferior Turbinate-Derived Mesenchymal Stem Cells to Repair Vocal Fold Injuries.

Science.gov (United States)

Kim, Choung-Soo; Choi, Hyunsu; Park, Ki Cheol; Kim, Sung Won; Sun, Dong-Il

2018-03-01

Objective This study investigated the ability of implanted human nasal inferior turbinate-derived mesenchymal stem cells (hTMSCs) to repair injured vocal folds. To this end, we used quantitative real-time polymerase chain reaction (PCR) to analyze the early phase of wound healing and histopathological analysis to explore the late phase of wound healing in xenograft animal models. Study Design Prospective animal study. Setting Research laboratory. Subjects and Methods The right-side lamina propria of the vocal fold was injured in 20 rabbits and 30 rats. Next, hTMSCs were implanted into half of the injured vocal folds (hTMSC groups). As a control, phosphate-buffered saline (PBS) was injected into the other half of the injured vocal folds (PBS groups). Rat vocal folds were harvested for polymerase chain reaction (PCR) at 1 week after injury. Rabbit vocal folds were evaluated endoscopically and the larynges harvested for histological and immunohistochemical examination at 2 and 8 weeks after injury. Results In the hTMSC group, PCR showed that hyaluronan synthase ( HAS) 1, HAS 2, and transforming growth factor ( TGF)-β1 were significantly upregulated compared with the PBS group. Procollagen type III ( COL III) messenger RNA expression was significantly upregulated in the PBS group compared with the normal group. Histological analyses showed that hTMSC administration afforded more favorable collagen and hyaluronic acid deposition than was evident in the controls. Implanted hTMSCs were observed in injured vocal folds 2 weeks after implantation. Conclusions Our results show that hTMSCs implantation into injured vocal folds facilitated vocal fold regeneration, with presenting antifibrotic effects.

The College Student's Freedom of Expression

Science.gov (United States)

Gibbs, Annette

1974-01-01

Discussion of means to ensure freedom of expression by college students. Areas of expression noted are student newspapers, lectures by off-campus speakers, freedom to assemble peaceably and freedom to associate. (EK)

Characterization of Trichome-Expressed BAHD Acyltransferases in Petunia axillaris Reveals Distinct Acylsugar Assembly Mechanisms within the Solanaceae1[OPEN

Science.gov (United States)

Uebler, Joseph B.; Liu, Xiaoxiao

2017-01-01

Acylsugars are synthesized in the glandular trichomes of the Solanaceae family and are implicated in protection against abiotic and biotic stress. Acylsugars are composed of either sucrose or glucose esterified with varying numbers of acyl chains of differing length. In tomato (Solanum lycopersicum), acylsugar assembly requires four acylsugar acyltransferases (ASATs) of the BAHD superfamily. Tomato ASATs catalyze the sequential esterification of acyl-coenzyme A thioesters to the R4, R3, R3ʹ, and R2 positions of sucrose, yielding a tetra-acylsucrose. Petunia spp. synthesize acylsugars that are structurally distinct from those of tomato. To explore the mechanisms underlying this chemical diversity, a Petunia axillaris transcriptome was mined for trichome preferentially expressed BAHDs. A combination of phylogenetic analyses, gene silencing, and biochemical analyses coupled with structural elucidation of metabolites revealed that acylsugar assembly is not conserved between tomato and petunia. In P. axillaris, tetra-acylsucrose assembly occurs through the action of four ASATs, which catalyze sequential addition of acyl groups to the R2, R4, R3, and R6 positions. Notably, in P. axillaris, PaxASAT1 and PaxASAT4 catalyze the acylation of the R2 and R6 positions of sucrose, respectively, and no clear orthologs exist in tomato. Similarly, petunia acylsugars lack an acyl group at the R3ʹ position, and congruently, an ortholog of SlASAT3, which catalyzes acylation at the R3ʹ position in tomato, is absent in P. axillaris. Furthermore, where putative orthologous relationships of ASATs are predicted between tomato and petunia, these are not supported by biochemical assays. Overall, these data demonstrate the considerable evolutionary plasticity of acylsugar biosynthesis. PMID:28701351

Folding of non-Euclidean curved shells

Science.gov (United States)

Bende, Nakul; Evans, Arthur; Innes-Gold, Sarah; Marin, Luis; Cohen, Itai; Santangelo, Christian; Hayward, Ryan

2015-03-01

Origami-based folding of 2D sheets has been of recent interest for a variety of applications ranging from deployable structures to self-folding robots. Though folding of planar sheets follows well-established principles, folding of curved shells involves an added level of complexity due to the inherent influence of curvature on mechanics. In this study, we use principles from differential geometry and thin shell mechanics to establish fundamental rules that govern folding of prototypical creased shells. In particular, we show how the normal curvature of a crease line controls whether the deformation is smooth or discontinuous, and investigate the influence of shell thickness and boundary conditions. We show that snap-folding of shells provides a route to rapid actuation on time-scales dictated by the speed of sound. The simple geometric design principles developed can be applied at any length-scale, offering potential for bio-inspired soft actuators for tunable optics, microfluidics, and robotics. This work was funded by the National Science Foundation through EFRI ODISSEI-1240441 with additional support to S.I.-G. through the UMass MRSEC DMR-0820506 REU program.

Improving Protein Fold Recognition by Deep Learning Networks

Science.gov (United States)

Jo, Taeho; Hou, Jie; Eickholt, Jesse; Cheng, Jianlin

2015-12-01

For accurate recognition of protein folds, a deep learning network method (DN-Fold) was developed to predict if a given query-template protein pair belongs to the same structural fold. The input used stemmed from the protein sequence and structural features extracted from the protein pair. We evaluated the performance of DN-Fold along with 18 different methods on Lindahl’s benchmark dataset and on a large benchmark set extracted from SCOP 1.75 consisting of about one million protein pairs, at three different levels of fold recognition (i.e., protein family, superfamily, and fold) depending on the evolutionary distance between protein sequences. The correct recognition rate of ensembled DN-Fold for Top 1 predictions is 84.5%, 61.5%, and 33.6% and for Top 5 is 91.2%, 76.5%, and 60.7% at family, superfamily, and fold levels, respectively. We also evaluated the performance of single DN-Fold (DN-FoldS), which showed the comparable results at the level of family and superfamily, compared to ensemble DN-Fold. Finally, we extended the binary classification problem of fold recognition to real-value regression task, which also show a promising performance. DN-Fold is freely available through a web server at http://iris.rnet.missouri.edu/dnfold.

Improving Protein Fold Recognition by Deep Learning Networks.

Science.gov (United States)

Jo, Taeho; Hou, Jie; Eickholt, Jesse; Cheng, Jianlin

2015-12-04

For accurate recognition of protein folds, a deep learning network method (DN-Fold) was developed to predict if a given query-template protein pair belongs to the same structural fold. The input used stemmed from the protein sequence and structural features extracted from the protein pair. We evaluated the performance of DN-Fold along with 18 different methods on Lindahl's benchmark dataset and on a large benchmark set extracted from SCOP 1.75 consisting of about one million protein pairs, at three different levels of fold recognition (i.e., protein family, superfamily, and fold) depending on the evolutionary distance between protein sequences. The correct recognition rate of ensembled DN-Fold for Top 1 predictions is 84.5%, 61.5%, and 33.6% and for Top 5 is 91.2%, 76.5%, and 60.7% at family, superfamily, and fold levels, respectively. We also evaluated the performance of single DN-Fold (DN-FoldS), which showed the comparable results at the level of family and superfamily, compared to ensemble DN-Fold. Finally, we extended the binary classification problem of fold recognition to real-value regression task, which also show a promising performance. DN-Fold is freely available through a web server at http://iris.rnet.missouri.edu/dnfold.

Synovial folds in equine articular process joints

DEFF Research Database (Denmark)

Thomsen, Line Nymann; Berg, Lise Charlotte; Markussen, Bo

2013-01-01

Cervical synovial folds have been suggested as a potential cause of neck pain in humans. Little is known about the extent and characteristics of cervical synovial folds in horses.......Cervical synovial folds have been suggested as a potential cause of neck pain in humans. Little is known about the extent and characteristics of cervical synovial folds in horses....

Stably Expressed Genes Involved in Basic Cellular Functions.

Directory of Open Access Journals (Sweden)

Kejian Wang

Full Text Available Stably Expressed Genes (SEGs whose expression varies within a narrow range may be involved in core cellular processes necessary for basic functions. To identify such genes, we re-analyzed existing RNA-Seq gene expression profiles across 11 organs at 4 developmental stages (from immature to old age in both sexes of F344 rats (n = 4/group; 320 samples. Expression changes (calculated as the maximum expression / minimum expression for each gene of >19000 genes across organs, ages, and sexes ranged from 2.35 to >109-fold, with a median of 165-fold. The expression of 278 SEGs was found to vary ≤4-fold and these genes were significantly involved in protein catabolism (proteasome and ubiquitination, RNA transport, protein processing, and the spliceosome. Such stability of expression was further validated in human samples where the expression variability of the homologous human SEGs was significantly lower than that of other genes in the human genome. It was also found that the homologous human SEGs were generally less subject to non-synonymous mutation than other genes, as would be expected of stably expressed genes. We also found that knockout of SEG homologs in mouse models was more likely to cause complete preweaning lethality than non-SEG homologs, corroborating the fundamental roles played by SEGs in biological development. Such stably expressed genes and pathways across life-stages suggest that tight control of these processes is important in basic cellular functions and that perturbation by endogenous (e.g., genetics or exogenous agents (e.g., drugs, environmental factors may cause serious adverse effects.

Crosstalk properties of 36-fold segmented symmetric hexagonal HPGe detectors

International Nuclear Information System (INIS)

Bruyneel, Bart; Reiter, Peter; Wiens, Andreas; Eberth, Juergen; Hess, Herbert; Pascovici, Gheorghe; Warr, Nigel; Weisshaar, Dirk

2009-01-01

Crosstalk properties of three 36-fold segmented, symmetric, large volume, HPGe detectors from the AGATA Collaboration were deduced from coincidence measurements performed with digitized segment and core signals after interaction of γ rays with energies of 1.33 MeV. The mean energy values measured by the core signal fluctuate for γ-ray interactions with energy deposited in two segments. A regular pattern is observed depending on the hit segment combinations. The core energy shifts deviate 0.03-0.06% from the average energy calibration. The segment-sum energy is reduced with respect to the core energy as a function of the decoupling capacitance and the segment multiplicity. The deviation of the segment-sum energies from multiplicity two events fluctuates within an interval of less than 0.1% depending on the different segment combinations. The energy shifts caused by crosstalk for the core and segment signals are comparable for all three detectors. A linear electronic model of the detector and preamplifier assembly was developed to evaluate the results. The fold-dependent energy shifts of the segment-sum energies are reproduced. The model yields a constant shift in all segments, proportional to the core signal. The measured crosstalk pattern and its intensity variation in the segments agree well with the calculated values. The regular variation observed in the core energies cannot be directly related to crosstalk and may be caused by other effects like electron trapping.

Dynamics of Folds in the Plane

Science.gov (United States)

Krylov, Nikolai A.; Rogers, Edwin L.

2011-01-01

Take a strip of paper and fold a crease intersecting the long edges, creating two angles. Choose one edge and consider the angle with the crease. Fold the opposite edge along the crease, creating a new crease that bisects the angle. Fold again, this time using the newly created crease and the initial edge, creating a new angle along the chosen…

MIDAS: A Modular DNA Assembly System for Synthetic Biology.

Science.gov (United States)

van Dolleweerd, Craig J; Kessans, Sarah A; Van de Bittner, Kyle C; Bustamante, Leyla Y; Bundela, Rudranuj; Scott, Barry; Nicholson, Matthew J; Parker, Emily J

2018-04-20

A modular and hierarchical DNA assembly platform for synthetic biology based on Golden Gate (Type IIS restriction enzyme) cloning is described. This enabling technology, termed MIDAS (for Modular Idempotent DNA Assembly System), can be used to precisely assemble multiple DNA fragments in a single reaction using a standardized assembly design. It can be used to build genes from libraries of sequence-verified, reusable parts and to assemble multiple genes in a single vector, with full user control over gene order and orientation, as well as control of the direction of growth (polarity) of the multigene assembly, a feature that allows genes to be nested between other genes or genetic elements. We describe the detailed design and use of MIDAS, exemplified by the reconstruction, in the filamentous fungus Penicillium paxilli, of the metabolic pathway for production of paspaline and paxilline, key intermediates in the biosynthesis of a range of indole diterpenes-a class of secondary metabolites produced by several species of filamentous fungi. MIDAS was used to efficiently assemble a 25.2 kb plasmid from 21 different modules (seven genes, each composed of three basic parts). By using a parts library-based system for construction of complex assemblies, and a unique set of vectors, MIDAS can provide a flexible route to assembling tailored combinations of genes and other genetic elements, thereby supporting synthetic biology applications in a wide range of expression hosts.

Gene expression patterns regulating embryogenesis based on the integrated de novo transcriptome assembly of the Japanese flounder.

Science.gov (United States)

Fu, Yuanshuai; Jia, Liang; Shi, Zhiyi; Zhang, Junling; Li, Wenjuan

2017-06-01

The Japanese flounder (Paralichthys olivaceus) is one of the most important commercial and biological marine fishes. However, the molecular biology involved during embryogenesis and early development of the Japanese flounder remains largely unknown due to a lack of genomic resources. A comprehensive and integrated transcriptome is necessary to study the molecular mechanisms of early development and to allow for the detailed characterization of gene expression patterns during embryogenesis; this approach is critical to understanding the processes that occur prior to mesectoderm formation during early embryonic development. In this study, more than 117.8 million 100bp PE reads were generated from pooled RNA extracted from unfertilized eggs to 41dph (days post-hatching) embryos and were sequenced using Illumina pair-end sequencing technology. In total, 121,513 transcripts (≥200bp) were obtained using de novo assembly. A sequence similarity search indicated that 52,338 transcripts show significant similarity to 22,462 known proteins from the NCBI non-redundant database and the Swiss-Prot protein database and were annotated using Blast2GO. GO terms were assigned to 44,627 transcripts with 12,006 functional terms, and 10,024 transcripts were assigned to 133 KEGG pathways. Furthermore, gene expression differences between the unfertilized egg and the gastrula embryo were analysed using Illumina RNA-Seq with single-read sequencing technology, and 24,837 differentially and specifically expressed transcripts were identified and included 5,286 annotated transcripts and 19,569 non-annotated transcripts. All of the expressed transcripts in the unfertilized egg and gastrula embryo were further classified as maternal, zygotic, or maternal-zygotic transcripts, which may help us to understand the roles of these transcripts during the embryonic development of the Japanese flounder. Thus, the results will contribute to an improved understanding of the gene expression patterns and

Teaching computers to fold proteins

DEFF Research Database (Denmark)

Winther, Ole; Krogh, Anders Stærmose

2004-01-01

A new general algorithm for optimization of potential functions for protein folding is introduced. It is based upon gradient optimization of the thermodynamic stability of native folds of a training set of proteins with known structure. The iterative update rule contains two thermodynamic averages...

Origami-Inspired Folding of Thick, Rigid Panels

Science.gov (United States)

Trease, Brian P.; Thomson, Mark W.; Sigel, Deborah A.; Walkemeyer, Phillip E.; Zirbel, Shannon; Howell, Larry; Lang, Robert

2014-01-01

To achieve power of 250 kW or greater, a large compression ratio of stowed-to-deployed area is needed. Origami folding patterns were used to inspire the folding of a solar array to achieve synchronous deployment; however, origami models are generally created for near-zero-thickness material. Panel thickness is one of the main challenges of origami-inspired design. Three origami-inspired folding techniques (flasher, square twist, and map fold) were created with rigid panels and hinges. Hinge components are added to the model to enable folding of thick, rigid materials. Origami models are created assuming zero (or near zero) thickness. When a material with finite thickness is used, the panels are required to bend around an increasingly thick fold as they move away from the center of the model. The two approaches for dealing with material thickness are to use membrane hinges to connect the panels, or to add panel hinges, or hinges of the same thickness, at an appropriate width to enable folding.

Endoglin expression in blood and endothelium is differentially regulated by modular assembly of the Ets/Gata hemangioblast code.

Science.gov (United States)

Pimanda, John E; Chan, Wan Y I; Wilson, Nicola K; Smith, Aileen M; Kinston, Sarah; Knezevic, Kathy; Janes, Mary E; Landry, Josette-Renée; Kolb-Kokocinski, Anja; Frampton, Jonathan; Tannahill, David; Ottersbach, Katrin; Follows, George A; Lacaud, Georges; Kouskoff, Valerie; Göttgens, Berthold

2008-12-01

Endoglin is an accessory receptor for TGF-beta signaling and is required for normal hemangioblast, early hematopoietic, and vascular development. We have previously shown that an upstream enhancer, Eng -8, together with the promoter region, mediates robust endothelial expression yet is inactive in blood. To identify hematopoietic regulatory elements, we used array-based methods to determine chromatin accessibility across the entire locus. Subsequent transgenic analysis of candidate elements showed that an endothelial enhancer at Eng +9 when combined with an element at Eng +7 functions as a strong hemato-endothelial enhancer. Chromatin immunoprecipitation (ChIP)-chip analysis demonstrated specific binding of Ets factors to the promoter as well as to the -8, +7+9 enhancers in both blood and endothelial cells. By contrast Pu.1, an Ets factor specific to the blood lineage, and Gata2 binding was only detected in blood. Gata2 was bound only at +7 and GATA motifs were required for hematopoietic activity. This modular assembly of regulators gives blood and endothelial cells the regulatory freedom to independently fine-tune gene expression and emphasizes the role of regulatory divergence in driving functional divergence.

A combined quantitative mass spectrometry and electron microscopy analysis of ribosomal 30S subunit assembly in E. coli.

Science.gov (United States)

Sashital, Dipali G; Greeman, Candacia A; Lyumkis, Dmitry; Potter, Clinton S; Carragher, Bridget; Williamson, James R

2014-10-14

Ribosome assembly is a complex process involving the folding and processing of ribosomal RNAs (rRNAs), concomitant binding of ribosomal proteins (r-proteins), and participation of numerous accessory cofactors. Here, we use a quantitative mass spectrometry/electron microscopy hybrid approach to determine the r-protein composition and conformation of 30S ribosome assembly intermediates in Escherichia coli. The relative timing of assembly of the 3' domain and the formation of the central pseudoknot (PK) structure depends on the presence of the assembly factor RimP. The central PK is unstable in the absence of RimP, resulting in the accumulation of intermediates in which the 3'-domain is unanchored and the 5'-domain is depleted for r-proteins S5 and S12 that contact the central PK. Our results reveal the importance of the cofactor RimP in central PK formation, and introduce a broadly applicable method for characterizing macromolecular assembly in cells.

Vocal fold hemorrhage: factors predicting recurrence.

Science.gov (United States)

Lennon, Christen J; Murry, Thomas; Sulica, Lucian

2014-01-01

Vocal fold hemorrhage is an acute phonotraumatic injury treated with voice rest; recurrence is a generally accepted indication for surgical intervention. This study aims to identify factors predictive of recurrence based on outcomes of a large clinical series. Retrospective cohort. Retrospective review of cases of vocal fold hemorrhage presenting to a university laryngology service. Demographic information was compiled. Videostroboscopic exams were evaluated for hemorrhage extent, presence of varix, mucosal lesion, and/or vocal fold paresis. Vocal fold hemorrhage recurrence was the main outcome measure. Follow-up telephone survey was used to complement clinical data. Forty-seven instances of vocal fold hemorrhage were evaluated (25M:22F; 32 professional voice users). Twelve of the 47 (26%) patients experienced recurrence. Only the presence of varix demonstrated significant association with recurrence (P = 0.0089) on multivariate logistic regression. Vocal fold hemorrhage recurred in approximately 26% of patients. Varix was a predictor of recurrence, with 48% of those with varix experiencing recurrence. Monitoring, behavioral management and/or surgical intervention may be indicated to treat patients with such characteristics. © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

Geometric U-folds in four dimensions

Science.gov (United States)

Lazaroiu, C. I.; Shahbazi, C. S.

2018-01-01

We describe a general construction of geometric U-folds compatible with a non-trivial extension of the global formulation of four-dimensional extended supergravity on a differentiable spin manifold. The topology of geometric U-folds depends on certain flat fiber bundles which encode how supergravity fields are globally glued together. We show that smooth non-trivial U-folds of this type can exist only in theories where both the scalar and space-time manifolds have non-trivial fundamental group and in addition the scalar map of the solution is homotopically non-trivial. Consistency with string theory requires smooth geometric U-folds to be glued using subgroups of the effective discrete U-duality group, implying that the fundamental group of the scalar manifold of such solutions must be a subgroup of the latter. We construct simple examples of geometric U-folds in a generalization of the axion-dilaton model of \

Modelling of isothermal remanence magnetisation curves for an assembly of macrospins

International Nuclear Information System (INIS)

Tournus, F.

2015-01-01

We present a robust and efficient framework to compute isothermal remanent magnetisation (IRM) curves for magnetic nanoparticle assemblies. The assembly is modelled by independent, randomly oriented, uniaxial macrospins and we use a Néel model to take into account the thermal relaxation. A simple analytic expression is established for a single size, in a sudden switching approximation, and is compared to more evolved models. We show that for realistic samples (necessarily presenting a size dispersion) the simple model is very satisfactory. With this framework, it is then possible to reliably simulate IRM curves, which can be compared to experimental measurements and used in a best fit procedure. We also examine the influence of several parameters on the IRM curves and we discuss the link between the irreversible susceptibility and the switching field distribution. - Highlights: • A framework to compute IRM curves for nanoparticle assemblies is presented. • A simple analytic expression (for a single size) is compared to more evolved models. • The simple expression can reliably simulate IRM curves for realistic samples. • Irreversible susceptibility and the influence of several parameters is discussed

Cooperative synchronized assemblies enhance orientation discrimination.

Science.gov (United States)

Samonds, Jason M; Allison, John D; Brown, Heather A; Bonds, A B

2004-04-27

There is no clear link between the broad tuning of single neurons and the fine behavioral capabilities of orientation discrimination. We recorded from populations of cells in the cat visual cortex (area 17) to examine whether the joint activity of cells can support finer discrimination than found in individual responses. Analysis of joint firing yields a substantial advantage (i.e., cooperation) in fine-angle discrimination. This cooperation increases to more considerable levels as the population of an assembly is increased. The cooperation in a population of six cells provides encoding of orientation with an information advantage that is at least 2-fold in terms of requiring either fewer cells or less time than independent coding. This cooperation suggests that correlated or synchronized activity can increase information.

Probing the structure of ribosome assembly intermediates in vivo using DMS and hydroxyl radical footprinting.

Science.gov (United States)

Hulscher, Ryan M; Bohon, Jen; Rappé, Mollie C; Gupta, Sayan; D'Mello, Rhijuta; Sullivan, Michael; Ralston, Corie Y; Chance, Mark R; Woodson, Sarah A

2016-07-01

The assembly of the Escherichia coli ribosome has been widely studied and characterized in vitro. Despite this, ribosome biogenesis in living cells is only partly understood because assembly is coupled with transcription, modification and processing of the pre-ribosomal RNA. We present a method for footprinting and isolating pre-rRNA as it is synthesized in E. coli cells. Pre-rRNA synthesis is synchronized by starvation, followed by nutrient upshift. RNA synthesized during outgrowth is metabolically labeled to facilitate isolation of recent transcripts. Combining this technique with two in vivo RNA probing methods, hydroxyl radical and DMS footprinting, allows the structure of nascent RNA to be probed over time. Together, these can be used to determine changes in the structures of ribosome assembly intermediates as they fold in vivo. Copyright © 2016 Elsevier Inc. All rights reserved.

Stability and assembly in vitro of bacteriophage PP7 virus-like particles

Directory of Open Access Journals (Sweden)

Peabody David S

2007-11-01

Full Text Available Abstract Background The stability of a virus-like particle (VLP is an important consideration for its use in nanobiotechnology. The icosahedral capsid of the RNA bacteriophage PP7 is cross-linked by disulfide bonds between coat protein dimers at its 5-fold and quasi-6-fold symmetry axes. This work determined the effects of these disulfides on the VLP's thermal stability. Results Measurements of the thermal denaturation behavior of PP7 VLPs in the presence and absence of a reducing agent show that disulfide cross-links substantially stabilize them against thermal denaturation. Although dimers in the capsid are linked to one another by disulfides, the two subunits of dimers themselves are held together only by non-covalent interactions. In an effort to confer even greater stability a new cross-link was introduced by genetically fusing two coat protein monomers, thus producing a "single-chain dimer" that assembles normally into a completely cross-linked VLP. However, subunit fusion failed to increase the thermal stability of the particles, even though it stabilized the isolated dimer. As a step toward gaining control of the internal composition of the capsid, conditions that promote the assembly of PP7 coat protein dimers into virus-like particles in vitro were established. Conclusion The presence of inter-dimer disulfide bonds greatly stabilizes the PP7 virus-like particle against thermal denaturation. Covalently cross-linking the subunits of the dimers themselves by genetically fusing them through a dipeptide linker sequence, offers no further stabilization of the VLP, although it does stabilize the dimer. PP7 capsids readily assemble in vitro in a reaction that requires RNA.

Optimizing de novo common wheat transcriptome assembly using short-read RNA-Seq data

Directory of Open Access Journals (Sweden)

Duan Jialei

2012-08-01

Full Text Available Abstract Background Rapid advances in next-generation sequencing methods have provided new opportunities for transcriptome sequencing (RNA-Seq. The unprecedented sequencing depth provided by RNA-Seq makes it a powerful and cost-efficient method for transcriptome study, and it has been widely used in model organisms and non-model organisms to identify and quantify RNA. For non-model organisms lacking well-defined genomes, de novo assembly is typically required for downstream RNA-Seq analyses, including SNP discovery and identification of genes differentially expressed by phenotypes. Although RNA-Seq has been successfully used to sequence many non-model organisms, the results of de novo assembly from short reads can still be improved by using recent bioinformatic developments. Results In this study, we used 212.6 million pair-end reads, which accounted for 16.2 Gb, to assemble the hexaploid wheat transcriptome. Two state-of-the-art assemblers, Trinity and Trans-ABySS, which use the single and multiple k-mer methods, respectively, were used, and the whole de novo assembly process was divided into the following four steps: pre-assembly, merging different samples, removal of redundancy and scaffolding. We documented every detail of these steps and how these steps influenced assembly performance to gain insight into transcriptome assembly from short reads. After optimization, the assembled transcripts were comparable to Sanger-derived ESTs in terms of both continuity and accuracy. We also provided considerable new wheat transcript data to the community. Conclusions It is feasible to assemble the hexaploid wheat transcriptome from short reads. Special attention should be paid to dealing with multiple samples to balance the spectrum of expression levels and redundancy. To obtain an accurate overview of RNA profiling, removal of redundancy may be crucial in de novo assembly.

How old is your fold?

NARCIS (Netherlands)

Winstanley, Henry F.; Abeln, Sanne; Deane, Charlotte M.

Motivation: At present there exists no age estimate for the different protein structures found in nature. It has become clear from occurrence studies that different folds arose at different points in evolutionary time. An estimation of the age of different folds would be a starting point for many

Helical self-organization and hierarchical self-assembly of an oligoheterocyclic pyridine-pyridazine strand into extended supramolecular fibers.

Science.gov (United States)

Cuccia, Louis A; Ruiz, Eliseo; Lehn, Jean-Marie; Homo, Jean-Claude; Schmutz, Marc

2002-08-02

The synthesis and characterization of an alternating pyridine-pyridazine strand comprising thirteen heterocycles are described. Spontaneous folding into a helical secondary structure is based on a general molecular self-organization process enforced by the conformational information encoded within the primary structure of the molecular strand itself. Conformational control based on heterocyclic "helicity codons" illustrates a strategy for designing folding properties into synthetic oligomers (foldamers). Strong intermolecular interactions of the highly ordered lock-washer subunits of compound 3 results in hierarchical supramolecular self-assembly into protofibrils and fibrils. Compound 3 also forms mechanically stable two-dimensional Langmuir-Blodgett and cast thin films.

Self-assembled nanoparticles of cholesterol-conjugated carboxymethyl curdlan as a novel carrier of epirubicin

International Nuclear Information System (INIS)

Li Lei; Gao Fuping; Tang Hongbo; Ba, Yonggang; Li Ruifeng; Li Xuemin; Liu Lingrong; Wang Yinsong; Zhang Qiqing

2010-01-01

The purpose of this study was to develop nanoparticles made of cholesterol-conjugated carboxymethyl curdlan (CCMC) entrapping epirubicin (EPB) and establish their in vitro and in vivo potential. CCMC was synthesized and characterized by Fourier transform infrared spectra (FT-IR) and proton nuclear magnetic resonance spectra ( 1 H NMR). The degrees of substitution (DS) of the cholesterol moiety were 2.3, 3.5 and 6.4, respectively. EPB-loaded CCMC-3.5 nanoparticles were prepared by the remote loading method. The physicochemical characteristics, drug loading efficiency and drug release kinetics of EPB-loaded CCMC-3.5 nanoparticles were characterized. The in vitro release profiles revealed that EPB release was sensitive to the pH as well as the drug loading contents. The cellular cytotoxicity and cellular uptake were accessed by using human cervical carcinoma (HeLa) cells. The EPB-loaded CCMC-3.5 nanoparticles were found to be more cytotoxic and have a broader distribution within the cells than the free EPB. The in vivo pharmacokinetics and biodistribution were investigated after intravenous injection in rats. Promisingly, a 4.0-fold increase in the mean residence time (MRT), a 4.31-fold increase in the half-life time and a 6.69-fold increase in the area under the curve (AUC 0→∞ ) of EPB were achieved for the EPB-loaded CCMC-3.5 self-assembled nanoparticles compared with the free EPB. The drug level was significantly increased in liver at 24 and 72 h; however, it decreased in heart at 8 and 24 h compared with the free EPB. The in vivo anti-tumor study indicated that the EPB-loaded CCMC-3.5 self-assembled nanoparticles showed greater anti-tumor efficacy than the free EPB. Taken together, the novel CCMC self-assembled nanoparticles might have potential application as anti-cancer drug carriers in a drug delivery system due to good results in vitro and in vivo.

Exact folded-band chaotic oscillator.

Science.gov (United States)

Corron, Ned J; Blakely, Jonathan N

2012-06-01

An exactly solvable chaotic oscillator with folded-band dynamics is shown. The oscillator is a hybrid dynamical system containing a linear ordinary differential equation and a nonlinear switching condition. Bounded oscillations are provably chaotic, and successive waveform maxima yield a one-dimensional piecewise-linear return map with segments of both positive and negative slopes. Continuous-time dynamics exhibit a folded-band topology similar to Rössler's oscillator. An exact solution is written as a linear convolution of a fixed basis pulse and a discrete binary sequence, from which an equivalent symbolic dynamics is obtained. The folded-band topology is shown to be dependent on the symbol grammar.

The Mammalian Cell Cycle Regulates Parvovirus Nuclear Capsid Assembly

Science.gov (United States)

Riolobos, Laura; Domínguez, Carlos; Kann, Michael; Almendral, José M.

2015-01-01

It is unknown whether the mammalian cell cycle could impact the assembly of viruses maturing in the nucleus. We addressed this question using MVM, a reference member of the icosahedral ssDNA nuclear parvoviruses, which requires cell proliferation to infect by mechanisms partly understood. Constitutively expressed MVM capsid subunits (VPs) accumulated in the cytoplasm of mouse and human fibroblasts synchronized at G0, G1, and G1/S transition. Upon arrest release, VPs translocated to the nucleus as cells entered S phase, at efficiencies relying on cell origin and arrest method, and immediately assembled into capsids. In synchronously infected cells, the consecutive virus life cycle steps (gene expression, proteins nuclear translocation, capsid assembly, genome replication and encapsidation) proceeded tightly coupled to cell cycle progression from G0/G1 through S into G2 phase. However, a DNA synthesis stress caused by thymidine irreversibly disrupted virus life cycle, as VPs became increasingly retained in the cytoplasm hours post-stress, forming empty capsids in mouse fibroblasts, thereby impairing encapsidation of the nuclear viral DNA replicative intermediates. Synchronously infected cells subjected to density-arrest signals while traversing early S phase also blocked VPs transport, resulting in a similar misplaced cytoplasmic capsid assembly in mouse fibroblasts. In contrast, thymidine and density arrest signals deregulating virus assembly neither perturbed nuclear translocation of the NS1 protein nor viral genome replication occurring under S/G2 cycle arrest. An underlying mechanism of cell cycle control was identified in the nuclear translocation of phosphorylated VPs trimeric assembly intermediates, which accessed a non-conserved route distinct from the importin α2/β1 and transportin pathways. The exquisite cell cycle-dependence of parvovirus nuclear capsid assembly conforms a novel paradigm of time and functional coupling between cellular and virus life

E2F-Rb complexes assemble and inhibit cdc25A transcription in cervical carcinoma cells following repression of human papillomavirus oncogene expression

DEFF Research Database (Denmark)

Wu, L; Goodwin, E C; Naeger, L K

2000-01-01

in the absence of E2 expression. Expression of the E2 protein also led to posttranscriptional increase in the level of E2F4, p105(Rb), and p130 and induced the formation of nuclear E2F4-p130 and E2F4-p105(Rb) complexes. This resulted in marked rearrangement of the protein complexes that formed at the distal E2F...... site in the cdc25A promoter, including the replacement of free E2F complexes with E2F4-p105(Rb) complexes. These experiments indicated that repression of E2F-responsive promoters following HPV E6/E7 repression was mediated by activation of the Rb tumor suppressor pathway and the assembly of repressing...

Vocal fold paresis - a debilitating and underdiagnosed condition.

Science.gov (United States)

Harris, G; O'Meara, C; Pemberton, C; Rough, J; Darveniza, P; Tisch, S; Cole, I

2017-07-01

To review the clinical signs of vocal fold paresis on laryngeal videostroboscopy, to quantify its impact on patients' quality of life and to confirm the benefit of laryngeal electromyography in its diagnosis. Twenty-nine vocal fold paresis patients were referred for laryngeal electromyography. Voice Handicap Index 10 results were compared to 43 patients diagnosed with vocal fold paralysis. Laryngeal videostroboscopy analysis was conducted to determine side of paresis. Blinded laryngeal electromyography confirmed vocal fold paresis in 92.6 per cent of cases, with vocal fold lag being the most common diagnostic sign. The laryngology team accurately predicted side of paresis in 76 per cent of cases. Total Voice Handicap Index 10 responses were not significantly different between vocal fold paralysis and vocal fold paresis groups (26.08 ± 0.21 and 22.93 ± 0.17, respectively). Vocal fold paresis has a significant impact on quality of life. This study shows that laryngeal electromyography is an important diagnostic tool. Patients with persisting dysphonia and apparently normal vocal fold movement, who fail to respond to appropriate speech therapy, should be investigated for a diagnosis of vocal fold paresis.

De Novo Assembly of the Pea (Pisum sativum L. Nodule Transcriptome

Directory of Open Access Journals (Sweden)

Vladimir A. Zhukov

2015-01-01

Full Text Available The large size and complexity of the garden pea (Pisum sativum L. genome hamper its sequencing and the discovery of pea gene resources. Although transcriptome sequencing provides extensive information about expressed genes, some tissue-specific transcripts can only be identified from particular organs under appropriate conditions. In this study, we performed RNA sequencing of polyadenylated transcripts from young pea nodules and root tips on an Illumina GAIIx system, followed by de novo transcriptome assembly using the Trinity program. We obtained more than 58,000 and 37,000 contigs from “Nodules” and “Root Tips” assemblies, respectively. The quality of the assemblies was assessed by comparison with pea expressed sequence tags and transcriptome sequencing project data available from NCBI website. The “Nodules” assembly was compared with the “Root Tips” assembly and with pea transcriptome sequencing data from projects indicating tissue specificity. As a result, approximately 13,000 nodule-specific contigs were found and annotated by alignment to known plant protein-coding sequences and by Gene Ontology searching. Of these, 581 sequences were found to possess full CDSs and could thus be considered as novel nodule-specific transcripts of pea. The information about pea nodule-specific gene sequences can be applied for gene-based markers creation, polymorphism studies, and real-time PCR.

Transcriptome assembly and expression profiling of molecular responses to cadmium toxicity in hepatopancreas of the freshwater crab Sinopotamon henanense

Science.gov (United States)

Sun, Min; Ting Li, Yi; Liu, Yang; Chin Lee, Shao; Wang, Lan

2016-01-01

Cadmium (Cd) pollution is a serious global problem, which causes irreversible toxic effects on animals. Freshwater crab, Sinopotamon henanense, is a useful environmental indicator since it is widely distributed in benthic habitats whereby it tends to accumulate Cd and other toxicants. However, its molecular responses to Cd toxicity remain unclear. In this study, we performed transcriptome sequencing and gene expression analyses of its hepatopancreas with and without Cd treatments. A total of 7.78 G clean reads were obtained from the pooled samples, and 68,648 unigenes with an average size of 622 bp were assembled, in which 5,436 were metabolism-associated and 2,728 were stimulus response-associated that include 380 immunity-related unigenes. Expression profile analysis demonstrated that most genes involved in macromolecular metabolism, oxidative phosphorylation, detoxification and anti-oxidant defense were up-regulated by Cd exposure, whereas immunity-related genes were down-regulated, except the genes involved in phagocytosis were up-regulated. The current data indicate that Cd exposure alters gene expressions in a concentration-dependent manner. Therefore, our results provide the first comprehensive S.henanense transcriptome dataset, which is useful for biological and ecotoxicological studies on this crab and its related species at molecular level, and some key Cd-responsive genes may provide candidate biomarkers for monitoring aquatic pollution by heavy metals.

Adaptive Origami for Efficiently Folded Structures

Science.gov (United States)

2016-02-01

heating. Although a large fold angle at a high temperature is desirable in order to extrapolate the origami geometry toward closure, more emphasis is...AFRL-RQ-WP-TR-2016-0020 ADAPTIVE ORIGAMI FOR EFFICIENTLY FOLDED STRUCTURES James J. Joo and Greg Reich Design and Analysis Branch... ORIGAMI FOR EFFICIENTLY FOLDED STRUCTURES 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) James J

Vocal fold paralysis secondary to phonotrauma.

Science.gov (United States)

Klein, Travis A L; Gaziano, Joy E; Ridley, Marion B

2014-01-01

A unique case of acute onset vocal fold paralysis secondary to phonotrauma is presented. The cause was forceful vocalization by a drill instructor on a firearm range. Imaging studies revealed extensive intralaryngeal and retropharyngeal hemorrhage. Laryngoscopy showed a complete left vocal fold paralysis. Relative voice rest was recommended, and the patient regained normal vocal fold mobility and function after approximately 12 weeks. Copyright © 2014 The Voice Foundation. All rights reserved.

CTP limitation increases expression of CTP synthase in Lactococcus lactis

DEFF Research Database (Denmark)

Jørgensen, C.M.; Hammer, Karin; Martinussen, Jan

2003-01-01

CTP synthase is encoded by the pyrG gene and catalyzes the conversion of UTP to CTP. A Lactococcus lactis pyrG mutant with a cytidine requirement was constructed, in which beta-galactosidase activity in a pyrG-lacLM transcriptional fusion was used to monitor gene expression of pyrG. A 10-fold...... decrease in the CTP pool induced by cytidine limitation was found to immediately increase expression of the L. lactis pyrG gene. The final level of expression of pyrG is 37-fold higher than the uninduced level. CTP limitation has pronounced effects on central cellular metabolism, and both RNA and protein...... for regulation of the pyrG gene. It is possible to fold the pyrG leader in an alternative structure that would prevent the formation of the terminator. We suggest a model for pyrG regulation in L. lactis, and probably in other gram-positive bacteria as well, in which pyrG expression is directly dependent...

A role for the nucleosome assembly proteins TAF-Iβ and NAP1 in the activation of BZLF1 expression and Epstein-Barr virus reactivation.

Science.gov (United States)

Mansouri, Sheila; Wang, Shan; Frappier, Lori

2013-01-01

The reactivation of Epstein-Barr virus (EBV) from latent to lytic infection begins with the expression of the viral BZLF1 gene, leading to a subsequent cascade of viral gene expression and amplification of the EBV genome. Using RNA interference, we show that nucleosome assembly proteins NAP1 and TAF-I positively contribute to EBV reactivation in epithelial cells through the induction of BZLF1 expression. In addition, overexpression of NAP1 or the β isoform of TAF-I (TAF-Iβ) in AGS cells latently infected with EBV was sufficient to induce BZLF1 expression. Chromatin immunoprecipitation experiments performed in AGS-EBV cells showed that TAF-I associated with the BZLF1 promoter upon lytic induction and affected local histone modifications by increasing H3K4 dimethylation and H4K8 acetylation. MLL1, the host protein known to dimethylate H3K4, was found to associate with the BZLF1 promoter upon lytic induction in a TAF-I-dependent manner, and MLL1 depletion decreased BZLF1 expression, confirming its contribution to lytic reactivation. The results indicate that TAF-Iβ promotes BZLF1 expression and subsequent lytic infection by affecting chromatin at the BZLF1 promoter.

Biomechanical simulation of vocal fold dynamics in adults based on laryngeal high-speed videoendoscopy.

Directory of Open Access Journals (Sweden)

Michael Döllinger

Full Text Available Human voice is generated in the larynx by the two oscillating vocal folds. Owing to the limited space and accessibility of the larynx, endoscopic investigation of the actual phonatory process in detail is challenging. Hence the biomechanics of the human phonatory process are still not yet fully understood. Therefore, we adapt a mathematical model of the vocal folds towards vocal fold oscillations to quantify gender and age related differences expressed by computed biomechanical model parameters.The vocal fold dynamics are visualized by laryngeal high-speed videoendoscopy (4000 fps. A total of 33 healthy young subjects (16 females, 17 males and 11 elderly subjects (5 females, 6 males were recorded. A numerical two-mass model is adapted to the recorded vocal fold oscillations by varying model masses, stiffness and subglottal pressure. For adapting the model towards the recorded vocal fold dynamics, three different optimization algorithms (Nelder-Mead, Particle Swarm Optimization and Simulated Bee Colony in combination with three cost functions were considered for applicability. Gender differences and age-related kinematic differences reflected by the model parameters were analyzed.The biomechanical model in combination with numerical optimization techniques allowed phonatory behavior to be simulated and laryngeal parameters involved to be quantified. All three optimization algorithms showed promising results. However, only one cost function seems to be suitable for this optimization task. The gained model parameters reflect the phonatory biomechanics for men and women well and show quantitative age- and gender-specific differences. The model parameters for younger females and males showed lower subglottal pressures, lower stiffness and higher masses than the corresponding elderly groups. Females exhibited higher subglottal pressures, smaller oscillation masses and larger stiffness than the corresponding similar aged male groups. Optimizing

Biomechanical simulation of vocal fold dynamics in adults based on laryngeal high-speed videoendoscopy.

Science.gov (United States)

Döllinger, Michael; Gómez, Pablo; Patel, Rita R; Alexiou, Christoph; Bohr, Christopher; Schützenberger, Anne

2017-01-01

Human voice is generated in the larynx by the two oscillating vocal folds. Owing to the limited space and accessibility of the larynx, endoscopic investigation of the actual phonatory process in detail is challenging. Hence the biomechanics of the human phonatory process are still not yet fully understood. Therefore, we adapt a mathematical model of the vocal folds towards vocal fold oscillations to quantify gender and age related differences expressed by computed biomechanical model parameters. The vocal fold dynamics are visualized by laryngeal high-speed videoendoscopy (4000 fps). A total of 33 healthy young subjects (16 females, 17 males) and 11 elderly subjects (5 females, 6 males) were recorded. A numerical two-mass model is adapted to the recorded vocal fold oscillations by varying model masses, stiffness and subglottal pressure. For adapting the model towards the recorded vocal fold dynamics, three different optimization algorithms (Nelder-Mead, Particle Swarm Optimization and Simulated Bee Colony) in combination with three cost functions were considered for applicability. Gender differences and age-related kinematic differences reflected by the model parameters were analyzed. The biomechanical model in combination with numerical optimization techniques allowed phonatory behavior to be simulated and laryngeal parameters involved to be quantified. All three optimization algorithms showed promising results. However, only one cost function seems to be suitable for this optimization task. The gained model parameters reflect the phonatory biomechanics for men and women well and show quantitative age- and gender-specific differences. The model parameters for younger females and males showed lower subglottal pressures, lower stiffness and higher masses than the corresponding elderly groups. Females exhibited higher subglottal pressures, smaller oscillation masses and larger stiffness than the corresponding similar aged male groups. Optimizing numerical models

Analysis Of Transcriptomes In A Porcine Tissue Collection Using RNA-Seq And Genome Assembly 10

DEFF Research Database (Denmark)

Hornshøj, Henrik; Thomsen, Bo; Hedegaard, Jakob

2011-01-01

The release of Sus scrofa genome assembly 10 supports improvement of the pig genome annotation and in depth transcriptome analyses using next-generation sequencing technologies. In this study we analyze RNA-seq reads from a tissue collection, including 10 separate tissues from Duroc boars and 10...... short read alignment software we mapped the reads to the genome assembly 10. We extracted contig sequences of gene transcripts using the Cufflinks software. Based on this information we identified expressed genes that are present in the genome assembly. The portion of these genes being previously known...... was roughly estimated by sequence comparison to known genes. Similarly, we searched for genes that are expressed in the tissues but not present in the genome assembly by aligning the non-genome-mapped reads to known gene transcripts. For the genes predicted to have alternative transcript variants by Cufflinks...

Sodium arsenite represses the expression of myogenin in C2C12 mouse myoblast cells through histone modifications and altered expression of Ezh2, Glp, and Igf-1

Energy Technology Data Exchange (ETDEWEB)

Hong, Gia-Ming [Environmental Toxicology Graduate Program, Clemson University, 132 Long Hall, Clemson, SC 29634 (United States); Present address: The University of Chicago, Section of Hematology/Oncology, 900 E. 57th Street, Room 7134, Chicago, IL 60637 (United States); Bain, Lisa J., E-mail: lbain@clemson.edu [Environmental Toxicology Graduate Program, Clemson University, 132 Long Hall, Clemson, SC 29634 (United States); Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC 29634 (United States)

2012-05-01

Arsenic is a toxicant commonly found in water systems and chronic exposure can result in adverse developmental effects including increased neonatal death, stillbirths, and miscarriages, low birth weight, and altered locomotor activity. Previous studies indicate that 20 nM sodium arsenite exposure to C2C12 mouse myocyte cells delayed myoblast differentiation due to reduced myogenin expression, the transcription factor that differentiates myoblasts into myotubes. In this study, several mechanisms by which arsenic could alter myogenin expression were examined. Exposing differentiating C2C12 cells to 20 nM arsenic increased H3K9 dimethylation (H3K9me2) and H3K9 trimethylation (H3K9me3) by 3-fold near the transcription start site of myogenin, which is indicative of increased repressive marks, and reduced H3K9 acetylation (H3K9Ac) by 0.5-fold, indicative of reduced permissive marks. Protein expression of Glp or Ehmt1, a H3-K9 methyltransferase, was also increased by 1.6-fold in arsenic-exposed cells. In addition to the altered histone remodeling status on the myogenin promoter, protein and mRNA levels of Igf-1, a myogenic growth factor, were significantly repressed by arsenic exposure. Moreover, a 2-fold induction of Ezh2 expression, and an increased recruitment of Ezh2 (3.3-fold) and Dnmt3a (∼ 2-fold) to the myogenin promoter at the transcription start site (− 40 to + 42), were detected in the arsenic-treated cells. Together, we conclude that the repressed myogenin expression in arsenic-exposed C2C12 cells was likely due to a combination of reduced expression of Igf-1, enhanced nuclear expression and promoter recruitment of Ezh2, and altered histone remodeling status on myogenin promoter (− 40 to + 42). -- Highlights: ► Igf-1 expression is decreased in C2C12 cells after 20 nM arsenite exposure. ► Arsenic exposure alters histone remodeling on the myogenin promoter. ► Glp expression, a H3–K9 methyltransferase, was increased in arsenic-exposed cells. ► Ezh2

Tuning iteration space slicing based tiled multi-core code implementing Nussinov's RNA folding.

Science.gov (United States)

Palkowski, Marek; Bielecki, Wlodzimierz

2018-01-15

RNA folding is an ongoing compute-intensive task of bioinformatics. Parallelization and improving code locality for this kind of algorithms is one of the most relevant areas in computational biology. Fortunately, RNA secondary structure approaches, such as Nussinov's recurrence, involve mathematical operations over affine control loops whose iteration space can be represented by the polyhedral model. This allows us to apply powerful polyhedral compilation techniques based on the transitive closure of dependence graphs to generate parallel tiled code implementing Nussinov's RNA folding. Such techniques are within the iteration space slicing framework - the transitive dependences are applied to the statement instances of interest to produce valid tiles. The main problem at generating parallel tiled code is defining a proper tile size and tile dimension which impact parallelism degree and code locality. To choose the best tile size and tile dimension, we first construct parallel parametric tiled code (parameters are variables defining tile size). With this purpose, we first generate two nonparametric tiled codes with different fixed tile sizes but with the same code structure and then derive a general affine model, which describes all integer factors available in expressions of those codes. Using this model and known integer factors present in the mentioned expressions (they define the left-hand side of the model), we find unknown integers in this model for each integer factor available in the same fixed tiled code position and replace in this code expressions, including integer factors, with those including parameters. Then we use this parallel parametric tiled code to implement the well-known tile size selection (TSS) technique, which allows us to discover in a given search space the best tile size and tile dimension maximizing target code performance. For a given search space, the presented approach allows us to choose the best tile size and tile dimension in

Multifunctional hybrid networks based on self assembling peptide sequences

Science.gov (United States)

Sathaye, Sameer

The overall aim of this dissertation is to achieve a comprehensive correlation between the molecular level changes in primary amino acid sequences of amphiphilic beta-hairpin peptides and their consequent solution-assembly properties and bulk network hydrogel behavior. This has been accomplished using two broad approaches. In the first approach, amino acid substitutions were made to peptide sequence MAX1 such that the hydrophobic surfaces of the folded beta-hairpins from the peptides demonstrate shape specificity in hydrophobic interactions with other beta-hairpins during the assembly process, thereby causing changes to the peptide nanostructure and bulk rheological properties of hydrogels formed from the peptides. Steric lock and key complementary hydrophobic interactions were designed to occur between two beta-hairpin molecules of a single molecule, LNK1 during beta-sheet fibrillar assembly of LNK1. Experimental results from circular dichroism, transmission electron microscopy and oscillatory rheology collectively indicate that the molecular design of the LNK1 peptide can be assigned the cause of the drastically different behavior of the networks relative to MAX1. The results indicate elimination or significant reduction of fibrillar branching due to steric complementarity in LNK1 that does not exist in MAX1, thus supporting the original hypothesis. As an extension of the designed steric lock and key complementarity between two beta-hairpin molecules of the same peptide molecule. LNK1, three new pairs of peptide molecules LP1-KP1, LP2-KP2 and LP3-KP3 that resemble complementary 'wedge' and 'trough' shapes when folded into beta-hairpins were designed and studied. All six peptides individually and when blended with their corresponding shape complement formed fibrillar nanostructures with non-uniform thickness values. Loose packing in the assembled structures was observed in all the new peptides as compared to the uniform tight packing in MAX1 by SANS analysis. This

Sarcoidosis Presenting as Bilateral Vocal Fold Immobility.

Science.gov (United States)

Hintze, Justin M; Gnagi, Sharon H; Lott, David G

2018-05-01

Bilateral true vocal fold paralysis is rarely attributable to inflammatory diseases. Sarcoidosis is a rare but important etiology of bilateral true vocal fold paralysis by compressive lymphadenopathy, granulomatous infiltration, and neural involvement. We describe the first reported case of sarcoidosis presenting as bilateral vocal fold immobility caused by direct fixation by granulomatous infiltration severe enough to necessitate tracheostomy insertion. In addition, we discuss the presentation, the pathophysiology, and the treatment of this disease with a review of the literature of previously reported cases of sarcoidosis-related vocal fold immobility. Sarcoidosis should therefore be an important consideration for the otolaryngologist's differential diagnosis of true vocal fold immobility. Copyright © 2018 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Geophysical perspective on the structural interference zone along the Neoproterozoic Brasília and Ribeira fold belts in West Gondwana

Directory of Open Access Journals (Sweden)

João Gabriel Motta

Full Text Available ABSTRACT: The Brasília and Ribeira fold belts have been established in south-southwestern São Francisco Craton during the Brasiliano-Pan African orogeny (0.9-0.5 Ga - Tonian to Cambrian, and played an important role in West Gondwana continent assembly. The region is given by a complex regional fold and thrust belt superposed by shearing during the orogeny late times, with superposing stress fields forming a structural interference zone. These thrust sheets encompasses assemblies from lower- to upper-crust from different major tectonic blocks (Paranapanema, São Francisco, and newly created metamorphic rocks. Re-evaluation of ground gravity datasets in a geologically constrained approach including seismology (CRUST1 model and magnetic data (EMAG2 model unveiled details on the deep- crust settings, and the overall geometry of the structural interference zone. The Simple Bouguer Anomaly map shows heterogeneous density distribution in the area, highlighting the presence of high-density, high metamorphic grade rocks along the Alterosa suture zone in the Socorro-Guaxupé Nappe, lying amid a series of metasedimentary thrust scales in a regional nappe system with important verticalization along regional shear zones. Forward gravity modeling favors interpretations of structural interference up North into Guaxupé Nappe. Comparison to geotectonic models shows similarities with modern accretionary belts, renewing the discussion.

24 April 2018: Ordinary General Assembly of the Staff Association!

CERN Multimedia

Staff Association

2018-01-01

In the first semester of each year, the Staff Association (SA) invites its members to attend and participate in the Ordinary General Assembly (OGA). This year the OGA will be held on Tuesday, 24 April 2018 from 14.00 to 16.00, Main Auditorium, Meyrin (500-1-001). During the Ordinary General Assembly, the activity and financial reports of the SA are presented and submitted for approval to the members. This is the occasion to get a global view on the activities of the SA, its management, and an opportunity to express your opinion, particularly by taking part in votes. Other items are listed on the agenda, as proposed by the Staff Council. Who can vote? Ordinary members (MPE) of the SA can take part in all votes. Associated members (MPA) of the SA and/or affiliated pensioners have a right to vote on those topics that are of direct interest to them. Who can give their opinion, and how? The Ordinary General Assembly is also the opportunity for members of the SA to express themselves through the addition of discus...

24 April 2018: Ordinary General Assembly of the Staff Association!

CERN Multimedia

Staff Association

2018-01-01

In the first semester of each year, the Staff Association (SA) invites its members to attend and participate in the Ordinary General Assembly (OGA). This year the OGA will be held on Thursday, 24 April 2018 from 14.00 to 16.00, Main Auditorium, Meyrin (500-1-001). During the Ordinary General Assembly, the activity and financial reports of the SA are presented and submitted for approval to the members. This is the occasion to get a global view on the activities of the SA, its management, and an opportunity to express your opinion, particularly by taking part in votes. Other items are listed on the agenda, as proposed by the Staff Council. Who can vote? Ordinary members (MPE) of the SA can take part in all votes. Associated members (MPA) of the SA and/or affiliated pensioners have a right to vote on those topics that are of direct interest to them. Who can give their opinion, and how? The Ordinary General Assembly is also the opportunity for members of the SA to express themselves through the addition of disc...

Extreme Mechanics: Self-Folding Origami

Science.gov (United States)

Santangelo, Christian D.

2017-03-01

Origami has emerged as a tool for designing three-dimensional structures from flat films. Because they can be fabricated by lithographic or roll-to-roll processing techniques, they have great potential for the manufacture of complicated geometries and devices. This article discusses the mechanics of origami and kirigami with a view toward understanding how to design self-folding origami structures. Whether an origami structure can be made to fold autonomously depends strongly on the geometry and kinematics of the origami fold pattern. This article collects some of the results on origami rigidity into a single framework, and discusses how these aspects affect the foldability of origami. Despite recent progress, most problems in origami and origami design remain completely open.

Treatment planning capability assessment of a beam shaping assembly for accelerator-based BNCT.

Science.gov (United States)

Herrera, M S; González, S J; Burlon, A A; Minsky, D M; Kreiner, A J

2011-12-01

Within the frame of an ongoing project to develop a folded Tandem-Electrostatic-Quadrupole accelerator facility for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT) a theoretical study was performed to assess the treatment planning capability of different configurations of an optimized beam shaping assembly for such a facility. In particular this study aims at evaluating treatment plans for a clinical case of Glioblastoma. Copyright © 2011 Elsevier Ltd. All rights reserved.

RNA-Seq profiling reveals novel hepatic gene expression pattern in aflatoxin B1 treated rats.

Science.gov (United States)

Merrick, B Alex; Phadke, Dhiral P; Auerbach, Scott S; Mav, Deepak; Stiegelmeyer, Suzy M; Shah, Ruchir R; Tice, Raymond R

2013-01-01

Deep sequencing was used to investigate the subchronic effects of 1 ppm aflatoxin B1 (AFB1), a potent hepatocarcinogen, on the male rat liver transcriptome prior to onset of histopathological lesions or tumors. We hypothesized RNA-Seq would reveal more differentially expressed genes (DEG) than microarray analysis, including low copy and novel transcripts related to AFB1's carcinogenic activity compared to feed controls (CTRL). Paired-end reads were mapped to the rat genome (Rn4) with TopHat and further analyzed by DESeq and Cufflinks-Cuffdiff pipelines to identify differentially expressed transcripts, new exons and unannotated transcripts. PCA and cluster analysis of DEGs showed clear separation between AFB1 and CTRL treatments and concordance among group replicates. qPCR of eight high and medium DEGs and three low DEGs showed good comparability among RNA-Seq and microarray transcripts. DESeq analysis identified 1,026 differentially expressed transcripts at greater than two-fold change (p<0.005) compared to 626 transcripts by microarray due to base pair resolution of transcripts by RNA-Seq, probe placement within transcripts or an absence of probes to detect novel transcripts, splice variants and exons. Pathway analysis among DEGs revealed signaling of Ahr, Nrf2, GSH, xenobiotic, cell cycle, extracellular matrix, and cell differentiation networks consistent with pathways leading to AFB1 carcinogenesis, including almost 200 upregulated transcripts controlled by E2f1-related pathways related to kinetochore structure, mitotic spindle assembly and tissue remodeling. We report 49 novel, differentially-expressed transcripts including confirmation by PCR-cloning of two unique, unannotated, hepatic AFB1-responsive transcripts (HAfT's) on chromosomes 1.q55 and 15.q11, overexpressed by 10 to 25-fold. Several potentially novel exons were found and exon refinements were made including AFB1 exon-specific induction of homologous family members, Ugt1a6 and Ugt1a7c. We find the

Multi-crease Self-folding by Global Heating.

Science.gov (United States)

Miyashita, Shuhei; Onal, Cagdas D; Rus, Daniela

2015-01-01

This study demonstrates a new approach to autonomous folding for the body of a 3D robot from a 2D sheet, using heat. We approach this challenge by folding a 0.27-mm sheetlike material into a structure. We utilize the thermal deformation of a contractive sheet sandwiched by rigid structural layers. During this baking process, the heat applied on the entire sheet induces contraction of the contracting layer and thus forms an instructed bend in the sheet. To attain the targeted folding angles, the V-fold spans method is used. The targeted angle θout can be kinematically encoded into crease geometry. The realization of this angle in the folded structure can be approximately controlled by a contraction angle θin. The process is non-reversible, is reliable, and is relatively fast. Our method can be applied simultaneously to all the folds in multi-crease origami structures. We demonstrate the use of this method to create a lightweight mobile robot.

[Clinical analysis of vocal fold firbrous mass].

Science.gov (United States)

Chen, Hao; Sun, Jing Wu; Wan, Guang Lun; Hu, Yan Ming

2018-03-01

To explore the character of laryngoscopy finding, voice, and therapy of vocal fold fibrous mass. Clinical data, morphology, voice character, surgery and pathology of 15 cases with vocal fold fibrous mass were analyzed. The morbidity of vocal fold fibrous mass might be related to overuse of voice and laryngopharyngeal reflex. Laryngoscopy revealed shuttle line appearance, smoothness and decreased mucosal wave of vocal fold. These patients were invalid for voice training and might be improved by surgery, but recovery is slow. The morbidity of vocal fold fibrous mass might be related to overuse of voice and laryngopharyngeal reflex. Conservative treatment is ineffective for this disease, and surgery might improve. Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.

[Nitrogen oxide is involved in the regulation of the Fe-S cluster assembly in proteins and the formation of biofilms by Escherichia coli cells].

Science.gov (United States)

Vasil'eva, S V; Streltsova, D A; Starostina, I A; Sanina, N A

2013-01-01

The functions of nitrogen oxide (NO) in the regulation of the reversible processes of Fe-S cluster assembly in proteins and the formation of Escherichia coli biofilms have been investigated. S-nitrosoglutathione (GSNO) and crystalline nitrosyl complexes of iron with sulfur-containing aliphatic ligands cisaconite (CisA) and penaconite have been used as NO donors for the first time. Wild-type E. coli cells of the strain MC4100, mutants deltaiscA and deltasufA, and the double paralog mutant deltaiscA/sufA with deletions in the alternative pathways of Fe2+ supply for cluster assembly (all derived from the above-named strain) were used in this study. Plankton growth of bacterial cultures, the mass of mature biofilms, and the expression of the SoxRS[2Fe-2S] regulon have been investigated and shown to depend on strain genotype, the process of Fe-S cluster assembly in iron-sulfur proteins, NO donor structure, and the presence of Fe2+ chelator ferene in the incubation medium. The antibiotic ciprofloxacine (CF) was used as an inhibitor of E. coli biofilm formation in the positive control. NO donors regulating Fe-S cluster assembly in E. coli have been shown to control plankton growth of the cultures and the process of mature biofilm formation; toxic doses of NO caused a dramatic (3- to 4-fold) stimulation of cell entry into biofilms as a response to nitrosative stress; NO donors CisA and GSNO in physiological concentrations suppressed the formation of mature biofilms, and the activity of these compounds was comparable to that of CE Regulation of both Fe-S cluster assembly in iron-sulfur proteins and biofilm formation by NO is indicative of the connection between these processes in E. coli.

Simultaneous temporally resolved DPIV and pressure measurements of symmetric oscillations in a scaled-up vocal fold model

Science.gov (United States)

Ringenberg, Hunter; Rogers, Dylan; Wei, Nathaniel; Krane, Michael; Wei, Timothy

2017-11-01

The objective of this study is to apply experimental data to theoretical framework of Krane (2013) in which the principal aeroacoustic source is expressed in terms of vocal fold drag, glottal jet dynamic head, and glottal exit volume flow, reconciling formal theoretical aeroacoustic descriptions of phonation with more traditional lumped-element descriptions. These quantities appear in the integral equations of motion for phonatory flow. In this way time resolved velocity field measurements can be used to compute time-resolved estimates of the relevant terms in the integral equations of motion, including phonation aeroacoustic source strength. A simplified 10x scale vocal fold model from Krane, et al. (2007) was used to examine symmetric, i.e. `healthy', oscillatory motion of the vocal folds. By using water as the working fluid, very high spatial and temporal resolution was achieved. Temporal variation of transglottal pressure was simultaneously measured with flow on the vocal fold model mid-height. Experiments were dynamically scaled to examine a range of frequencies corresponding to male and female voice. The simultaneity of the pressure and flow provides new insights into the aeroacoustics associated with vocal fold oscillations. Supported by NIH Grant No. 2R01 DC005642-11.

MicroRNA-15b regulates reversion-inducing cysteine-rich protein with Kazal motifs (RECK) expression in human uterine leiomyoma.

Science.gov (United States)

Guan, Yichun; Guo, Lankai; Zukerberg, Lawrence; Rueda, Bo R; Styer, Aaron K

2016-08-17

Human uterine leiomyoma (fibroids; LYO) are the most common benign neoplasms in reproductive-aged women. Dysregulated extracellular matrix and irregular LYO reversion-inducing cysteine-rich protein with Kazal motifs (RECK) expression are thought to be mediated by aberrant microRNA (miR) expression. The relationship of miR-15b and RECK expression in LYO has not been studied. The expression levels of miR-15b and RECK were determined by quantitative RT-PCR, Western blot, and immunohistochemistry in cultures derived from commercial primary leiomyoma (cpLYO) and myometrial (cpMYO) cell lines and leiomyoma (pLYO) and myometrium (pMYO) tissue from surgical samples respectively. The relationship between miR-15b and RECK expression in cpLYO and pLYO (compared to their respective myometrial controls) was evaluated following transfection of cell cultures with either miR-15b mimic or inhibitor. Elevated levels of miR-15b were observed in cpLYO (2.82-fold; p = 0.04) and pLYO cell (1.30-fold; p = 0.0001) cultures respectively compared to corresponding MYO cell controls. Following transfection with miR-15b mimic, cpLYO cells (0.62-fold; p < 0.0001) and pLYO cells (0.68-fold; p < 0.0001) demonstrated reduced RECK protein expression. Following transfection with miR-15b inhibitor, cpLYO cells (1.20-fold; p < 0.0001) and pLYO cells (1.31-fold; p = 0.0007) demonstrated elevated RECK protein expression. RECK protein expression was reduced in pLYO tissues (0.73-fold; p < 0.0001) and pLYO (0.47-fold; p = 0.047) cells when compared to the corresponding MYO tissue controls. Our findings suggest that miR-15b negatively regulates RECK expression in LYO, and increased miR-15b and decreased RECK expression may contribute to the pathobiology of LYO. The functional significance of miR-15b and RECK expression warrants further investigation as potential therapeutic targets for the treatment of human LYO.

Mapping of near surface fold structures with GPR and ERT near Steinbrunn (Northern Burgenland, Austria)

Science.gov (United States)

Kreutzer, Ingrid; Chwatal, Werner; Häusler, Hermann; Scheibz, Jürgen; Steirer, Fritz

2014-05-01

. Therefore we assume that the mapped fold shape structures underlie almost the entire investigation area of about one square kilometre in size. Considering the very shallow facies of the Upper Pannonian deposits and compared to fold structures documented in the neighbouring coal mine of Neufeld (Häusler, 2012b), the geophysical investigations of these buckling structures support the hypothesis of a tectonic origin. Exner, U., Draganits, E., Grasemann, B., 2009. Folding in Miocene, unconsolidated clastic sediments (Vienna basin, Austria) - gravitational versus tectonic forces, Trabajos de Geología, Universidad de Oviedo, 29, 269-272, Oviedo. Grundtner, M.-L., Harzhauser, M., Mandic, O., Draganits, E., Gier, S., Exner, U., Wagreich, M., 2009. Zur Sedimentologie der Sandgrube Steinbrunn (Pannonium, Österreich), Jahrbuch der Geologischen Bundesanstalt, 149, 441-451, Wien. Häusler, H., 2012a. Contribution to the discussion of folded Pannonian strata in the Southern Vienna Basin, Geophysical Research Abstracts, Vol. 14, EGU2012-5201, EGU General Assembly 2012, Vienna. Häusler, H., 2012b. Folded Pannonian beds along the Austroalpine frame of the southern Vienna Basin, PANGEO Austria 2012 (10th anniversary), 15.-20. Sept. 2012, Abstracts, 55-56, Salzburg.

Gene expression in peripheral immune cells following cardioembolic stroke is sexually dimorphic.

Directory of Open Access Journals (Sweden)

Boryana Stamova

Full Text Available Epidemiological studies suggest that sex has a role in the pathogenesis of cardioembolic stroke. Since stroke is a vascular disease, identifying sexually dimorphic gene expression changes in blood leukocytes can inform on sex-specific risk factors, response and outcome biology. We aimed to examine the sexually dimorphic immune response following cardioembolic stroke by studying the differential gene expression in peripheral white blood cells.Blood samples from patients with cardioembolic stroke were obtained at ≤3 hours (prior to treatment, 5 hours and 24 hours (after treatment after stroke onset (n = 23; 69 samples and compared with vascular risk factor controls without symptomatic vascular diseases (n = 23, 23 samples (ANCOVA, false discovery rate p≤0.05, |fold change| ≥1.2. mRNA levels were measured on whole-genome Affymetrix microarrays. There were more up-regulated than down-regulated genes in both sexes, and females had more differentially expressed genes than males following cardioembolic stroke. Female gene expression was associated with cell death and survival, cell-cell signaling and inflammation. Male gene expression was associated with cellular assembly, organization and compromise. Immune response pathways were over represented at ≤3, 5 and 24 h after stroke in female subjects but only at 24 h in males. Neutrophil-specific genes were differentially expressed at 3, 5 and 24 h in females but only at 5 h and 24 h in males.There are sexually dimorphic immune cell expression profiles following cardioembolic stroke. Future studies are needed to confirm the findings using qRT-PCR in an independent cohort, to determine how they relate to risk and outcome, and to compare to other causes of ischemic stroke.

Factors that affect coseismic folds in an overburden layer

Science.gov (United States)

Zeng, Shaogang; Cai, Yongen

2018-03-01

Coseismic folds induced by blind thrust faults have been observed in many earthquake zones, and they have received widespread attention from geologists and geophysicists. Numerous studies have been conducted regarding fold kinematics; however, few have studied fold dynamics quantitatively. In this paper, we establish a conceptual model with a thrust fault zone and tectonic stress load to study the factors that affect coseismic folds and their formation mechanisms using the finite element method. The numerical results show that the fault dip angle is a key factor that controls folding. The greater the dip angle is, the steeper the fold slope. The second most important factor is the overburden thickness. The thicker the overburden is, the more gradual the fold. In this case, folds are difficult to identify in field surveys. Therefore, if a fold can be easily identified with the naked eye, the overburden is likely shallow. The least important factors are the mechanical parameters of the overburden. The larger the Young's modulus of the overburden is, the smaller the displacement of the fold and the fold slope. Strong horizontal compression and vertical extension in the overburden near the fault zone are the main mechanisms that form coseismic folds.

Autonomous assembly of synthetic oligonucleotides built from an expanded DNA alphabet. Total synthesis of a gene encoding kanamycin resistance

Directory of Open Access Journals (Sweden)

Kristen K. Merritt

2014-10-01

Full Text Available Background: Many synthetic biologists seek to increase the degree of autonomy in the assembly of long DNA (L-DNA constructs from short synthetic DNA fragments, which are today quite inexpensive because of automated solid-phase synthesis. However, the low information density of DNA built from just four nucleotide “letters”, the presence of strong (G:C and weak (A:T nucleobase pairs, the non-canonical folded structures that compete with Watson–Crick pairing, and other features intrinsic to natural DNA, generally prevent the autonomous assembly of short single-stranded oligonucleotides greater than a dozen or so.Results: We describe a new strategy to autonomously assemble L-DNA constructs from fragments of synthetic single-stranded DNA. This strategy uses an artificially expanded genetic information system (AEGIS that adds nucleotides to the four (G, A, C, and T found in standard DNA by shuffling hydrogen-bonding units on the nucleobases, all while retaining the overall Watson–Crick base-pairing geometry. The added information density allows larger numbers of synthetic fragments to self-assemble without off-target hybridization, hairpin formation, and non-canonical folding interactions. The AEGIS pairs are then converted into standard pairs to produce a fully natural L-DNA product. Here, we report the autonomous assembly of a gene encoding kanamycin resistance using this strategy. Synthetic fragments were built from a six-letter alphabet having two AEGIS components, 5-methyl-2’-deoxyisocytidine and 2’-deoxyisoguanosine (respectively S and B, at their overlapping ends. Gaps in the overlapped assembly were then filled in using DNA polymerases, and the nicks were sealed by ligase. The S:B pairs in the ligated construct were then converted to T:A pairs during PCR amplification. When cloned into a plasmid, the product was shown to make Escherichia coli resistant to kanamycin. A parallel study that attempted to assemble similarly sized genes

De novo Assembly and Analysis of the Chilean Pencil Catfish Trichomycterus areolatus Transcriptome

Science.gov (United States)

Schulze, Thomas T.; Ali, Jonathan M.; Bartlett, Maggie L.; McFarland, Madalyn M.; Clement, Emalie J.; Won, Harim I.; Sanford, Austin G.; Monzingo, Elyssa B.; Martens, Matthew C.; Hemsley, Ryan M.; Kumar, Sidharta; Gouin, Nicolas; Kolok, Alan S.; Davis, Paul H.

2016-01-01

Trichomycterus areolatus is an endemic species of pencil catfish that inhabits the riffles and rapids of many freshwater ecosystems of Chile. Despite its unique adaptation to Chile's high gradient watersheds and therefore potential application in the investigation of ecosystem integrity and environmental contamination, relatively little is known regarding the molecular biology of this environmental sentinel. Here, we detail the assembly of the Trichomycterus areolatus transcriptome, a molecular resource for the study of this organism and its molecular response to the environment. RNA-Seq reads were obtained by next-generation sequencing with an Illumina® platform and processed using PRINSEQ. The transcriptome assembly was performed using TRINITY assembler. Transcriptome validation was performed by functional characterization with KOG, KEGG, and GO analyses. Additionally, differential expression analysis highlights sex-specific expression patterns, and a list of endocrine and oxidative stress related transcripts are included. PMID:27672404

RNAslider: a faster engine for consecutive windows folding and its application to the analysis of genomic folding asymmetry.

Science.gov (United States)

Horesh, Yair; Wexler, Ydo; Lebenthal, Ilana; Ziv-Ukelson, Michal; Unger, Ron

2009-03-04

Scanning large genomes with a sliding window in search of locally stable RNA structures is a well motivated problem in bioinformatics. Given a predefined window size L and an RNA sequence S of size N (L free energy (MFE) for the folding of each of the L-sized substrings of S. The consecutive windows folding problem can be naively solved in O(NL3) by applying any of the classical cubic-time RNA folding algorithms to each of the N-L windows of size L. Recently an O(NL2) solution for this problem has been described. Here, we describe and implement an O(NLpsi(L)) engine for the consecutive windows folding problem, where psi(L) is shown to converge to O(1) under the assumption of a standard probabilistic polymer folding model, yielding an O(L) speedup which is experimentally confirmed. Using this tool, we note an intriguing directionality (5'-3' vs. 3'-5') folding bias, i.e. that the minimal free energy (MFE) of folding is higher in the native direction of the DNA than in the reverse direction of various genomic regions in several organisms including regions of the genomes that do not encode proteins or ncRNA. This bias largely emerges from the genomic dinucleotide bias which affects the MFE, however we see some variations in the folding bias in the different genomic regions when normalized to the dinucleotide bias. We also present results from calculating the MFE landscape of a mouse chromosome 1, characterizing the MFE of the long ncRNA molecules that reside in this chromosome. The efficient consecutive windows folding engine described in this paper allows for genome wide scans for ncRNA molecules as well as large-scale statistics. This is implemented here as a software tool, called RNAslider, and applied to the scanning of long chromosomes, leading to the observation of features that are visible only on a large scale.

CAR expression and inducibility of CYP2B genes in liver of rats treated with PB-like inducers

International Nuclear Information System (INIS)

Pustylnyak, Vladimir O.; Gulyaeva, Lyudmila F.; Lyakhovich, Vyacheslav V.

2005-01-01

The expression of the CAR gene and inducibility of CYP2B protein in the liver of male Wistar rats treated with phenobarbital (PB) and triphenyldioxane (TPD) were investigated. To clarify the role of phosphorylation/dephosphorylation in these processes, rats were treated with inhibitors of Ca 2+ /calmodulin-dependent kinase II (W 7 ) or protein phosphatases PP1 and PP2A (OA) before induction. Constitutive expression of the CAR gene in livers of untreated rats was detected by multiplex RT-PCR. Treatment with W 7 resulted in a 2.8-fold induction of CAR gene expression, whereas OA led to a 2.4-fold decrease of the mRNA level. The same results were obtained for CYP2B genes expression, which were increased by W 7 treatment (two-fold) and decreased by OA (2.3-fold). PB-induction did not lead to significant alteration in the level of CAR gene expression, although CYP2B genes expression was enhanced two-fold over control values. TPD caused a two-fold increase of both CAR and CYP2B mRNA levels. Both inducers reduced the effects of inhibitors on CAR gene expression. Results of EMSA showed that PB, TPD or W 7 alone induced formation of complexes of NR1 with nuclear proteins. Appearance of the complexes correlated with an increase in CYP2B expression, and their intensities were modulated by the protein kinase inhibitors. Thus, our results demonstrate that constitutive expressions of CAR as well as CYP2B during induction are regulated by phosphorylation/dephosphorylation processes

Physics of protein folding

Science.gov (United States)

Finkelstein, A. V.; Galzitskaya, O. V.

2004-04-01

Protein physics is grounded on three fundamental experimental facts: protein, this long heteropolymer, has a well defined compact three-dimensional structure; this structure can spontaneously arise from the unfolded protein chain in appropriate environment; and this structure is separated from the unfolded state of the chain by the “all-or-none” phase transition, which ensures robustness of protein structure and therefore of its action. The aim of this review is to consider modern understanding of physical principles of self-organization of protein structures and to overview such important features of this process, as finding out the unique protein structure among zillions alternatives, nucleation of the folding process and metastable folding intermediates. Towards this end we will consider the main experimental facts and simple, mostly phenomenological theoretical models. We will concentrate on relatively small (single-domain) water-soluble globular proteins (whose structure and especially folding are much better studied and understood than those of large or membrane and fibrous proteins) and consider kinetic and structural aspects of transition of initially unfolded protein chains into their final solid (“native”) 3D structures.

The expression of superoxide dismutase in Mytilus coruscus under various stressors.

Science.gov (United States)

Wu, Jiong; Bao, Miaomiao; Ge, Delong; Huo, Liping; Lv, Zhenming; Chi, Changfeng; Liao, Zhi; Liu, Huihui

2017-11-01

Superoxide dismutases (SODs), a by-product of antioxidative defence system, protects organisms for eliminating excess reactive oxygen species (ROS) and maintaining the redox balance of immune system. The complete open reading frames (ORFs) of Cu/Zn-SOD and Mn-SOD were identified from Mytilus coruscus (designated as McSOD and MnSOD) by homologous cloning. The sequence lengths were 474bp and 687bp, encoding 157 and 228 amino acids respectively. The deduced amino acid sequences of McSOD and MnSOD shared high identities with Cu/Zn-SOD and Mn-SOD from other mollusca. The distributions of McSOD and MnSOD were detected in six tissues including adductor, hemocyte, gill, gonad, mantle and hepatopancreas, and the highest expressions were both in gills. The temporal expression of McSOD and MnSOD were up-regulated in gills under a variety of stress factors, including Vibrio parahemolyticus, Aeromonas hydrophila, Cu 2+ and Pb 2+ . After being challenged with V. Parahemolyticus, the expressions of McSOD and MnSOD were increased rapidly at the initial hours, reaching the peaks of 4.9-fold and 15.3-fold respectively, and got to the highest levels of 43.5-fold and 7.1-fold after being challenged with A. hydrophila. The highest point of McSOD mRNA appeared at 15 d after being exposed to copper (7-fold at 0.5 mg/L and 13.2-fold at 1.5 mg/L), except for 0.1 mg/L group of Cu 2+ maintaining to the normal level, but plumbum at 1 d (2.4-fold at 1.0 mg/L and 4.4-fold at 3.0 mg/L) and at 15 d (2.1-fold at 0.2 mg/L). The temporal expression peaks of MnSOD appeared differently after exposing to copper of various concentrations (0.1 mg/L at 10 d with 4.7-fold, 0.5 mg/L at 1 d with 17.9-fold and 1.5 mg/L at 3 d with 13.2-fold). Whereas in plumbum exposing treatments, the 3.0 mg/L group jumped to the peak at 1 d (18.2-fold), the 0.2 mg/L and 1.0 mg/L groups had little change and maintained at the normal level throughout the experiment. The results provided several new

Selective Assembly of Na,K-ATPase α2β2 Heterodimers in the Heart

Science.gov (United States)

Habeck, Michael; Tokhtaeva, Elmira; Nadav, Yotam; Ben Zeev, Efrat; Ferris, Sean P.; Kaufman, Randal J.; Bab-Dinitz, Elizabeta; Kaplan, Jack H.; Dada, Laura A.; Farfel, Zvi; Tal, Daniel M.; Katz, Adriana; Sachs, George; Vagin, Olga; Karlish, Steven J. D.

2016-01-01

The Na,K-ATPase α2 subunit plays a key role in cardiac muscle contraction by regulating intracellular Ca2+, whereas α1 has a more conventional role of maintaining ion homeostasis. The β subunit differentially regulates maturation, trafficking, and activity of α-β heterodimers. It is not known whether the distinct role of α2 in the heart is related to selective assembly with a particular one of the three β isoforms. We show here by immunofluorescence and co-immunoprecipitation that α2 is preferentially expressed with β2 in T-tubules of cardiac myocytes, forming α2β2 heterodimers. We have expressed human α1β1, α2β1, α2β2, and α2β3 in Pichia pastoris, purified the complexes, and compared their functional properties. α2β2 and α2β3 differ significantly from both α2β1 and α1β1 in having a higher K0.5K+ and lower K0.5Na+ for activating Na,K-ATPase. These features are the result of a large reduction in binding affinity for extracellular K+ and shift of the E1P-E2P conformational equilibrium toward E1P. A screen of perhydro-1,4-oxazepine derivatives of digoxin identified several derivatives (e.g. cyclobutyl) with strongly increased selectivity for inhibition of α2β2 and α2β3 over α1β1 (range 22–33-fold). Molecular modeling suggests a possible basis for isoform selectivity. The preferential assembly, specific T-tubular localization, and low K+ affinity of α2β2 could allow an acute response to raised ambient K+ concentrations in physiological conditions and explain the importance of α2β2 for cardiac muscle contractility. The high sensitivity of α2β2 to digoxin derivatives explains beneficial effects of cardiac glycosides for treatment of heart failure and potential of α2β2-selective digoxin derivatives for reducing cardiotoxicity. PMID:27624940

Carrier Transport Enhancement in Conjugated Polymers through Interfacial Self-Assembly of Solution-State Aggregates

KAUST Repository

Zhao, Kui

2016-07-13

We demonstrate that local and long range orders of poly(3-hexylthiophene) (P3HT) semicrystalline films can be synergistically improved by combining chemical functionalization of the dielectric surface with solution-state disentanglement and pre-aggregation of P3HT in a theta solvent, leading to a very significant enhancement of the field effect carrier mobility. The pre-aggregation and surface functionalization effects combine to enhance the carrier mobility nearly 100-fold as compared with standard film preparation by spin-coating, and nearly 10-fold increase over the benefits of pre-aggregation alone. In situ quartz crystal microbalance with dissipation (QCM-D) experiments reveal enhanced deposition of pre-aggregates on surfaces modified with an alkyl-terminated self-assembled monolayer (SAM) in comparison to un-aggregated polymer chains. Additional investigations reveal the combined pre-aggregation and surface functionalization significantly enhances local order of the conjugated polymer through planarization and extension of the conjugated backbone of the polymer which clearly translate to significant improvements of carrier transport at the semiconductor-dielectric interface in organic thin film transistors. This study points to opportunities in combining complementary routes, such as well-known pre-aggregation with substrate chemical functionalization, to enhance the polymer self-assembly and improve its interfacial order with benefits for transport properties.

In vivo measurement of vocal fold surface resistance.

Science.gov (United States)

Mizuta, Masanobu; Kurita, Takashi; Dillon, Neal P; Kimball, Emily E; Garrett, C Gaelyn; Sivasankar, M Preeti; Webster, Robert J; Rousseau, Bernard

2017-10-01

A custom-designed probe was developed to measure vocal fold surface resistance in vivo. The purpose of this study was to demonstrate proof of concept of using vocal fold surface resistance as a proxy of functional tissue integrity after acute phonotrauma using an animal model. Prospective animal study. New Zealand White breeder rabbits received 120 minutes of airflow without vocal fold approximation (control) or 120 minutes of raised intensity phonation (experimental). The probe was inserted via laryngoscope and placed on the left vocal fold under endoscopic visualization. Vocal fold surface resistance of the middle one-third of the vocal fold was measured after 0 (baseline), 60, and 120 minutes of phonation. After the phonation procedure, the larynx was harvested and prepared for transmission electron microscopy. In the control group, vocal fold surface resistance values remained stable across time points. In the experimental group, surface resistance (X% ± Y% relative to baseline) was significantly decreased after 120 minutes of raised intensity phonation. This was associated with structural changes using transmission electron microscopy, which revealed damage to the vocal fold epithelium after phonotrauma, including disruption of the epithelium and basement membrane, dilated paracellular spaces, and alterations to epithelial microprojections. In contrast, control vocal fold specimens showed well-preserved stratified squamous epithelia. These data demonstrate the feasibility of measuring vocal fold surface resistance in vivo as a means of evaluating functional vocal fold epithelial barrier integrity. Device prototypes are in development for additional testing, validation, and for clinical applications in laryngology. NA Laryngoscope, 127:E364-E370, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

MARATHON DESPITE UNILATERAL VOCAL FOLD PARALYSIS

Directory of Open Access Journals (Sweden)

Matthias Echternach

2008-06-01

Full Text Available The principal symptoms of unilateral vocal fold paralysis are hoarseness and difficulty in swallowing. Dyspnea is comparatively rare (Laccourreye et al., 2003. The extent to which unilateral vocal fold paralysis may lead to respiratory problems at all - in contrast to bilateral vocal fold paralysis- has not yet well been determined. On the one hand, inspiration is impaired with unilateral vocal fold paralysis; on the other hand, neither the position of the vocal fold paralysis nor the degree of breathiness correlates with respiratory parameters (Cantarella et al., 2003; 2005. The question of what respiratory stress a patient with a vocal fold paresis can endure has not yet been dealt with.A 43 year-old female patient was suffering from recurrent unspecific respiratory complaints for four months after physical activity. During training for a marathon, she experienced no difficulty in breathing. These unspecific respiratory complaints occurred only after athletic activity and persisted for hours. The patient observed neither an increased coughing nor a stridor. Her voice remained unaltered during the attacks, nor were there any signs of a symptomatic gastroesophageal reflux or infectious disease. A cardio-pulmonary and a radiological examination by means of an X-ray of the thorax also revealed no pathological phenomena. As antiallergic and antiobstructive therapy remained unsuccessful, a laryngological examination was performed in order to exclude a vocal cord dysfunction.Surprisingly enough, the laryngostroboscopy showed, as an initial description, a vocal fold paralysis of the left vocal fold in median position (Figure 1. The anamnestic background for the cause was unclear. The only clue was a thoracotomy on the left side due to a pleuritis in childhood. A subsequent laryngoscopic examination had never been performed. Good mucosa waves and amplitudes were shown bilateral with complete glottal closure. Neither in the acoustic analysis, nor in the

Evaluation of strategies to control Fab light chain dimer during mammalian expression and purification: A universal one-step process for purification of correctly assembled Fab.

Science.gov (United States)

Spooner, Jennifer; Keen, Jenny; Nayyar, Kalpana; Birkett, Neil; Bond, Nicholas; Bannister, David; Tigue, Natalie; Higazi, Daniel; Kemp, Benjamin; Vaughan, Tristan; Kippen, Alistair; Buchanan, Andrew

2015-07-01

Fabs are an important class of antibody fragment as both research reagents and therapeutic agents. There are a plethora of methods described for their recombinant expression and purification. However, these do not address the issue of excessive light chain production that forms light chain dimers nor do they describe a universal purification strategy. Light chain dimer impurities and the absence of a universal Fab purification strategy present persistent challenges for biotechnology applications using Fabs, particularly around the need for bespoke purification strategies. This study describes methods to address light chain dimer formation during Fab expression and identifies a novel CH 1 affinity resin as a simple and efficient one-step purification for correctly assembled Fab. © 2015 Wiley Periodicals, Inc.

Fold and Fit: Space Conserving Shape Editing

KAUST Repository

Ibrahim, Mohamed

2017-09-01

We present a framework that folds man-made objects in a structure-aware manner for space-conserving storage and transportation. Given a segmented 3D mesh of a man-made object, our framework jointly optimizes for joint locations, the folding order, and folding angles for each part of the model, enabling it to transform into a spatially efficient configuration while keeping its original functionality as intact as possible. That is, if a model is supposed to withstand several forces in its initial state to serve its functionality, our framework places the joints between the parts of the model such that the model can withstand forces with magnitudes that are comparable to the magnitudes applied on the unedited model. Furthermore, if the folded shape is not compact, our framework proposes further segmentation of the model to improve its compactness in its folded state.

Identifying Regulatory Patterns at the 3'end Regions of Over-expressed and Under-expressed Genes

KAUST Repository

Othoum, Ghofran K

2013-05-01

Promoters, neighboring regulatory regions and those extending further upstream of the 5’end of genes, are considered one of the main components affecting the expression status of genes in a specific phenotype. More recently research by Chen et al. (2006, 2012) and Mapendano et al. (2010) demonstrated that the 3’end regulatory regions of genes also influence gene expression. However, the association between the regulatory regions surrounding 3’end of genes and their over- or under-expression status in a particular phenotype has not been systematically studied. The aim of this study is to ascertain if regulatory regions surrounding the 3’end of genes contain sufficient regulatory information to correlate genes with their expression status in a particular phenotype. Over- and under-expressed ovarian cancer (OC) genes were used as a model. Exploratory analysis of the 3’end regions were performed by transforming the annotated regions using principal component analysis (PCA), followed by clustering the transformed data thereby achieving a clear separation of genes with different expression status. Additionally, several classification algorithms such as Naïve Bayes, Random Forest and Support Vector Machine (SVM) were tested with different parameter settings to analyze the discriminatory capacity of the 3’end regions of genes related to their gene expression status. The best performance was achieved using the SVM classification model with 10-fold cross-validation that yielded an accuracy of 98.4%, sensitivity of 99.5% and specificity of 92.5%. For gene expression status for newly available instances, based on information derived from the 3’end regions, an SVM predictive model was developed with 10-fold cross-validation that yielded an accuracy of 67.0%, sensitivity of 73.2% and specificity of 61.0%. Moreover, building an SVM with polynomial kernel model to PCA transformed data yielded an accuracy of 83.1%, sensitivity of 92.5% and specificity of 74.8% using

Identifying Regulatory Patterns at the 3'end Regions of Over-expressed and Under-expressed Genes

KAUST Repository

Othoum, Ghofran K

2013-01-01

Promoters, neighboring regulatory regions and those extending further upstream of the 5’end of genes, are considered one of the main components affecting the expression status of genes in a specific phenotype. More recently research by Chen et al. (2006, 2012) and Mapendano et al. (2010) demonstrated that the 3’end regulatory regions of genes also influence gene expression. However, the association between the regulatory regions surrounding 3’end of genes and their over- or under-expression status in a particular phenotype has not been systematically studied. The aim of this study is to ascertain if regulatory regions surrounding the 3’end of genes contain sufficient regulatory information to correlate genes with their expression status in a particular phenotype. Over- and under-expressed ovarian cancer (OC) genes were used as a model. Exploratory analysis of the 3’end regions were performed by transforming the annotated regions using principal component analysis (PCA), followed by clustering the transformed data thereby achieving a clear separation of genes with different expression status. Additionally, several classification algorithms such as Naïve Bayes, Random Forest and Support Vector Machine (SVM) were tested with different parameter settings to analyze the discriminatory capacity of the 3’end regions of genes related to their gene expression status. The best performance was achieved using the SVM classification model with 10-fold cross-validation that yielded an accuracy of 98.4%, sensitivity of 99.5% and specificity of 92.5%. For gene expression status for newly available instances, based on information derived from the 3’end regions, an SVM predictive model was developed with 10-fold cross-validation that yielded an accuracy of 67.0%, sensitivity of 73.2% and specificity of 61.0%. Moreover, building an SVM with polynomial kernel model to PCA transformed data yielded an accuracy of 83.1%, sensitivity of 92.5% and specificity of 74.8% using

Hantavirus Gn and Gc glycoproteins self-assemble into virus-like particles.

Science.gov (United States)

Acuña, Rodrigo; Cifuentes-Muñoz, Nicolás; Márquez, Chantal L; Bulling, Manuela; Klingström, Jonas; Mancini, Roberta; Lozach, Pierre-Yves; Tischler, Nicole D

2014-02-01

How hantaviruses assemble and exit infected cells remains largely unknown. Here, we show that the expression of Andes (ANDV) and Puumala (PUUV) hantavirus Gn and Gc envelope glycoproteins lead to their self-assembly into virus-like particles (VLPs) which were released to cell supernatants. The viral nucleoprotein was not required for particle formation. Further, a Gc endodomain deletion mutant did not abrogate VLP formation. The VLPs were pleomorphic, exposed protrusions and reacted with patient sera.

Ionizing Radiation Stimulates Expression of Pro-Osteoclastogenic Genes in Marrow and Skeletal Tissue

Science.gov (United States)

Alwood, J. S.; Shahnazari, M.; Chicana, B.; Schreurs, A. S.; Kumar, A.; Bartolini, A.; Shirazi-Fard, Y.; Globus, R. K.

2015-01-01

Exposure to ionizing radiation can cause rapid mineral loss and increase bone-resorbing osteoclasts within metabolically-active, cancellous-bone tissue leading to structural deficits. To better understand mechanisms involved in rapid, radiation-induced bone loss, we determined the influence of total-body irradiation on expression of select cytokines known both to stimulate osteoclastogenesis and contribute to inflammatory bone disease. Adult (16wk), male C57BL/6J mice were exposed to either 2Gy gamma rays (137Cs, 0.8Gy/min) or heavy ions (56Fe, 600MeV, 0.50-1.1Gy/min); this dose corresponds to either a single fraction of radiotherapy (typical total dose is =10Gy) or accumulates over long-duration, interplanetary missions. Serum, marrow, and mineralized tissue were harvested 4hrs-7d later. Gamma irradiation caused a prompt (2.6-fold within 4hrs) and persistent (peaking at 4.1-fold within 1d) rise in the expression of the obligate osteoclastogenic cytokine, receptor activator of nuclear factor kappaB-ligand (Rankl) within marrow cells over controls. Similarly, Rankl expression peaked in marrow cells within 3d of iron exposure (9.2-fold). Changes in Rankl expression induced by gamma irradiation preceded and overlapped with a rise in expression of other pro-osteoclastic cytokines in marrow (e.g., monocyte chemotactic protein-1 increased 11.9-fold, tumor necrosis factor-alpha increased 1.7- fold over controls). Marrow expression of the RANKL decoy receptor, osteoprotegerin (Opg), also rose after irradiation (11.3-fold). The ratio Rankl/Opg in marrow was increased 1.8-fold, a net pro-resorption balance. As expected, radiation increased a serum marker of resorption (tartrate resistant acid phosphatase) and led to cancellous bone loss (16% decrease in bone volume/total volume) through reduced trabecular struts. We conclude that total-body irradiation (gamma or heavy-ion) caused temporal, concerted regulation of gene expression within marrow and mineralized tissue for

Arabidopsis Tic40 expression in tobacco chloroplasts results in massive proliferation of the inner envelope membrane and upregulation of associated proteins.

Science.gov (United States)

Singh, Nameirakpam Dolendro; Li, Ming; Lee, Sueng-Bum; Schnell, Danny; Daniell, Henry

2008-12-01

The chloroplast inner envelope membrane (IM) plays essential roles in lipid synthesis, metabolite transport, and cellular signaling in plants. We have targeted a model nucleus-encoded IM protein from Arabidopsis thaliana, pre-Tic40-His, by relocating its expression from the nucleus to the chloroplast genome. Pre-Tic40-His was properly targeted, processed, and inserted. It attained correct topology and was folded and assembled into a TIC complex, where it accounted for up to 15% of the total chloroplast protein. These results confirm the existence of a novel pathway for protein targeting to the IM. Tic40-His overexpression resulted in a massive proliferation of the IM (up to 19 layers in electron micrographs) without significant effects on plant growth or reproduction. Consistent with IM proliferation, the expression levels of other endogenous IM proteins (IEP37, PPT, Tic110) were significantly (10-fold) upregulated but those of outer envelope membrane (Toc159), stromal (hsp93, cpn60), or thylakoid (LHCP, OE23) proteins were not increased, suggesting retrograde signal transduction between chloroplast and nuclear genomes to increase lipid and protein components for accommodation of increased accumulation of Tic40. This study opens the door for understanding the regulation of membrane biogenesis within the organelle and the utilization of transgenic chloroplasts as bioreactors for hyperaccumulation of membrane proteins for biotechnological applications.

FANTOM5 CAGE profiles of human and mouse reprocessed for GRCh38 and GRCm38 genome assemblies.

Science.gov (United States)

Abugessaisa, Imad; Noguchi, Shuhei; Hasegawa, Akira; Harshbarger, Jayson; Kondo, Atsushi; Lizio, Marina; Severin, Jessica; Carninci, Piero; Kawaji, Hideya; Kasukawa, Takeya

2017-08-29

The FANTOM5 consortium described the promoter-level expression atlas of human and mouse by using CAGE (Cap Analysis of Gene Expression) with single molecule sequencing. In the original publications, GRCh37/hg19 and NCBI37/mm9 assemblies were used as the reference genomes of human and mouse respectively; later, the Genome Reference Consortium released newer genome assemblies GRCh38/hg38 and GRCm38/mm10. To increase the utility of the atlas in forthcoming researches, we reprocessed the data to make them available on the recent genome assemblies. The data include observed frequencies of transcription starting sites (TSSs) based on the realignment of CAGE reads, and TSS peaks that are converted from those based on the previous reference. Annotations of the peak names were also updated based on the latest public databases. The reprocessed results enable us to examine frequencies of transcription initiations on the recent genome assemblies and to refer promoters with updated information across the genome assemblies consistently.

Self-folding miniature elastic electric devices

International Nuclear Information System (INIS)

Miyashita, Shuhei; Meeker, Laura; Rus, Daniela; Tolley, Michael T; Wood, Robert J

2014-01-01

Printing functional materials represents a considerable impact on the access to manufacturing technology. In this paper we present a methodology and validation of print-and-self-fold miniature electric devices. Polyvinyl chloride laminated sheets based on metalized polyester film show reliable self-folding processes under a heat application, and it configures 3D electric devices. We exemplify this technique by fabricating fundamental electric devices, namely a resistor, capacitor, and inductor. Namely, we show the development of a self-folded stretchable resistor, variable resistor, capacitive strain sensor, and an actuation mechanism consisting of a folded contractible solenoid coil. Because of their pre-defined kinematic design, these devices feature elasticity, making them suitable as sensors and actuators in flexible circuits. Finally, an RLC circuit obtained from the integration of developed devices is demonstrated, in which the coil based actuator is controlled by reading a capacitive strain sensor. (paper)

In vivo roles of BamA, BamB and BamD in the biogenesis of BamA, a core protein of the β-barrel assembly machine of Escherichia coli

Science.gov (United States)

Misra, Rajeev; Stikeleather, Ryan; Gabriele, Rebecca

2014-01-01

Assembly of the β-barrel outer membrane proteins (OMPs) is an essential cellular process in Gram negative bacteria and in the mitochondria and chloroplasts of eukaryotes—two organelles of bacterial origin. Central to this process is the conserved β-barrel OMP that belongs to the Omp85 superfamily. In Escherichia coli, BamA is the core β-barrel OMP, and together with four outer membrane lipoproteins, BamBCDE, constitute the β-barrel assembly machine (BAM). In this paper, we investigated the roles of BamD, an essential lipoprotein, and BamB in BamA biogenesis. Depletion of BamD caused impairment in BamA biogenesis and cessation of cell growth. These defects of BamD depletion were partly reversed by single amino acid substitutions mapping within the β-barrel domain of BamA. However, in the absence of BamB, the positive effects of the β-barrel substitutions on BamA biogenesis under BamD depletion conditions were nullified. By employing a BamA protein bearing one such substitution, F494L, it was demonstrated that the mutant BamA protein could not only assemble without BamD, but it could also facilitate the assembly of wild-type BamA expressed in trans. Based on these data, we propose a model in which the Bam lipoproteins, which are localized to the outer membrane by the BAM-independent Lol pathway, aid in the creation of new BAM complexes by serving as outer membrane receptors and folding factors for nascent BamA molecules. The newly assembled BAM holocomplex then catalyzes the assembly of substrate OMPs and BamA. These in vivo findings are corroborated by recently published in vitro data. PMID:24792419

In vivo roles of BamA, BamB and BamD in the biogenesis of BamA, a core protein of the β-barrel assembly machine of Escherichia coli.

Science.gov (United States)

Misra, Rajeev; Stikeleather, Ryan; Gabriele, Rebecca

2015-03-13

Assembly of the β-barrel outer membrane proteins (OMPs) is an essential cellular process in Gram-negative bacteria and in the mitochondria and chloroplasts of eukaryotes--two organelles of bacterial origin. Central to this process is the conserved β-barrel OMP that belongs to the Omp85 superfamily. In Escherichia coli, BamA is the core β-barrel OMP and, together with four outer membrane lipoproteins, BamBCDE, constitutes the β-barrel assembly machine (BAM). In this paper, we investigated the roles of BamD, an essential lipoprotein, and BamB in BamA biogenesis. Depletion of BamD caused impairment in BamA biogenesis and cessation of cell growth. These defects of BamD depletion were partly reversed by single-amino-acid substitutions mapping within the β-barrel domain of BamA. However, in the absence of BamB, the positive effects of the β-barrel substitutions on BamA biogenesis under BamD depletion conditions were nullified. By employing a BamA protein bearing one such substitution, F474L, it was demonstrated that the mutant BamA protein could not only assemble without BamD but also facilitate the assembly of wild-type BamA expressed in trans. Based on these data, we propose a model in which the Bam lipoproteins, which are localized to the outer membrane by the BAM-independent Lol pathway, aid in the creation of new BAM complexes by serving as outer membrane receptors and folding factors for nascent BamA molecules. The newly assembled BAM holocomplex then catalyzes the assembly of substrate OMPs and BamA. These in vivo findings are corroborated by recently published in vitro data. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of insulin-like growth factor-1 on the assembly and secretion of very low-density lipoproteins in cow hepatocytes in vitro.

Science.gov (United States)

Li, Xinwei; Guan, Yuan; Li, Ying; Wu, Dianjun; Liu, Lei; Deng, Qinghua; Li, Xiaobing; Wang, Zhe; Liu, Guowen

2016-01-15

Fatty liver is a major metabolic disorder of dairy cows. One important reason is that hepatic very low-density lipoproteins (VLDL) assembly was significant decreased in dairy cows with fatty liver. In addition, the impairment of insulin-like growth factor (IGF)-1 synthesis was involved in the development of fatty liver. Therefore, the objective of this study was to investigate the effects of IGF-1 on the VLDL assembly in cow hepatocytes. In this study, cow hepatocytes were cultured and then transfected with Ad-GFP-IGF-1 (inhibited the IGF-1 expression) and Ad-GFP (negative control), and treated with different concentrations of IGF-1, respectively. The results showed that IGF-1 increased the mRNA abundance of apolipoprotein B100 (ApoB100), apolipoprotein E (ApoE), microsomal triglyceride transfer protein (MTTP), and low-density lipoprotein receptor (LDLR) and then increased the VLDL assembly in cow hepatocytes. Nevertheless, impairment of IGF-1 expression by Ad-GFP-IGF-1 could inhibit above genes expression and VLDL assembly in hepatocytes. Taken together, these results indicate that IGF-1 increases the VLDL assembly and impairment of IGF-1 expression decreases the VLDL assembly in cow hepatocytes. Copyright © 2016 Elsevier Inc. All rights reserved.

Microvascular lesions of the true vocal fold.

Science.gov (United States)

Postma, G N; Courey, M S; Ossoff, R H

1998-06-01

Microvascular lesions, also called varices or capillary ectasias, in contrast to vocal fold polyps with telangiectatic vessels, are relatively small lesions arising from the microcirculation of the vocal fold. Varices are most commonly seen in female professional vocalists and may be secondary to repetitive trauma, hormonal variations, or repeated inflammation. Microvascular lesions may either be asymptomatic or cause frank dysphonia by interrupting the normal vibratory pattern, mass, or closure of the vocal folds. They may also lead to vocal fold hemorrhage, scarring, or polyp formation. Laryngovideostroboscopy is the key in determining the functional significance of vocal fold varices. Management of patients with a varix includes medical therapy, speech therapy, and occasionally surgical vaporization. Indications for surgery are recurrent hemorrhage, enlargement of the varix, development of a mass in conjunction with the varix or hemorrhage, and unacceptable dysphonia after maximal medical and speech therapy due to a functionally significant varix.

Acute exposure to vibration is an apoptosis-inducing stimulus in the vocal fold epithelium.

Science.gov (United States)

Novaleski, Carolyn K; Kimball, Emily E; Mizuta, Masanobu; Rousseau, Bernard

2016-10-01

Clinical voice disorders pose significant communication-related challenges to patients. The purpose of this study was to quantify the rate of apoptosis and tumor necrosis factor-alpha (TNF-α) signaling in vocal fold epithelial cells in response to increasing time-doses and cycle-doses of vibration. 20 New Zealand white breeder rabbits were randomized to three groups of time-doses of vibration exposure (30, 60, 120min) or a control group (120min of vocal fold adduction and abduction). Estimated cycle-doses of vocal fold vibration were extrapolated based on mean fundamental frequency. Laryngeal tissue specimens were evaluated for apoptosis and gene transcript and protein levels of TNF-α. Results revealed that terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was significantly higher after 120min of vibration compared to the control. Transmission electron microscopy (TEM) revealed no significant effect of time-dose on the mean area of epithelial cell nuclei. Extrapolated cycle-doses of vibration exposure were closely related to experimental time-dose conditions, although no significant correlations were observed with TUNEL staining or mean area of epithelial cell nuclei. TUNEL staining was positively correlated with TNF-α protein expression. Our findings suggest that apoptosis can be induced in the vocal fold epithelium after 120min of modal intensity phonation. In contrast, shorter durations of vibration exposure do not result in apoptosis signaling. However, morphological features of apoptosis are not observed using TEM. Future studies are necessary to examine the contribution of abnormal apoptosis to vocal fold diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

Compartmentalization Technologies via Self-Assembly and Cross-Linking of Amphiphilic Random Block Copolymers in Water.

Science.gov (United States)

Matsumoto, Mayuko; Terashima, Takaya; Matsumoto, Kazuma; Takenaka, Mikihito; Sawamoto, Mitsuo

2017-05-31

Orthogonal self-assembly and intramolecular cross-linking of amphiphilic random block copolymers in water afforded an approach to tailor-make well-defined compartments and domains in single polymer chains and nanoaggregates. For a double compartment single-chain polymer, an amphiphilic random block copolymer bearing hydrophilic poly(ethylene glycol) (PEG) and hydrophobic dodecyl, benzyl, and olefin pendants was synthesized by living radical polymerization (LRP) and postfunctionalization; the dodecyl and benzyl units were incorporated into the different block segments, whereas PEG pendants were statistically attached along a chain. The copolymer self-folded via the orthogonal self-assembly of hydrophobic dodecyl and benzyl pendants in water, followed by intramolecular cross-linking, to form a single-chain polymer carrying double yet distinct hydrophobic nanocompartments. A single-chain cross-linked polymer with a chlorine terminal served as a globular macroinitiator for LRP to provide an amphiphilic tadpole macromolecule comprising a hydrophilic nanoparticle and a hydrophobic polymer tail; the tadpole thus self-assembled into multicompartment aggregates in water.

Approaching climate-adaptive facades with foldings

DEFF Research Database (Denmark)

Sack-Nielsen, Torsten

2014-01-01

envelopes based on folding principles such as origami. Three major aspects cover the project’s interest in this topic: Shape, kinetics and the application of new multi-functional materials form the interdisciplinary framework of this research. Shape// Initially small paper sketch models demonstrate folding...

Decreased interleukin-20 expression in scleroderma skin contributes to cutaneous fibrosis.

Science.gov (United States)

Kudo, Hideo; Jinnin, Masatoshi; Asano, Yoshihide; Trojanowska, Maria; Nakayama, Wakana; Inoue, Kuniko; Honda, Noritoshi; Kajihara, Ikko; Makino, Katsunari; Fukushima, Satoshi; Ihn, Hironobu

2014-06-01

To clarify the role of interleukin-20 (IL-20) in the regulatory mechanism of extracellular matrix expression and to determine the contribution of IL-20 to the phenotype of systemic sclerosis (SSc). Protein and messenger RNA (mRNA) levels of collagen, Fli-1, IL-20, and IL-20 receptor (IL-20R) were analyzed using polymerase chain reaction (PCR) array, immunoblotting, immunohistochemical staining, enzyme-linked immunosorbent assay, and real-time PCR. PCR array revealed that IL-20 decreased gene expression of α2(I) collagen (0.03-fold), Smad3 (0.02-fold), and endoglin (0.05-fold) in cultured normal dermal fibroblasts. Fli-1 protein expression was induced by IL-20 (~2-fold). The inhibition of collagen by IL-20, the induction of Fli-1 by IL-20, and the reduction of Smad3 and endoglin by IL-20 were also observed in SSc fibroblasts. Serum IL-20 levels were reduced only slightly in SSc patients but were significantly decreased in patients with scleroderma spectrum disorders (the prodromal stage of SSc) compared with those in normal subjects (111.3 pg/ml versus 180.4 pg/ml; P value of IL-20 and IL-20R, their function and expression in vivo should be further studied. Copyright © 2014 by the American College of Rheumatology.

Design and simulation of origami structures with smooth folds.

Science.gov (United States)

Peraza Hernandez, E A; Hartl, D J; Lagoudas, D C

2017-04-01

Origami has enabled new approaches to the fabrication and functionality of multiple structures. Current methods for origami design are restricted to the idealization of folds as creases of zeroth-order geometric continuity. Such an idealization is not proper for origami structures of non-negligible fold thickness or maximum curvature at the folds restricted by material limitations. For such structures, folds are not properly represented as creases but rather as bent regions of higher-order geometric continuity. Such fold regions of arbitrary order of continuity are termed as smooth folds . This paper presents a method for solving the following origami design problem: given a goal shape represented as a polygonal mesh (termed as the goal mesh ), find the geometry of a single planar sheet, its pattern of smooth folds, and the history of folding motion allowing the sheet to approximate the goal mesh. The parametrization of the planar sheet and the constraints that allow for a valid pattern of smooth folds are presented. The method is tested against various goal meshes having diverse geometries. The results show that every determined sheet approximates its corresponding goal mesh in a known folded configuration having fold angles obtained from the geometry of the goal mesh.

Melody discrimination and protein fold classification

Directory of Open Access Journals (Sweden)

Robert P. Bywater

2016-10-01

Full Text Available One of the greatest challenges in theoretical biophysics and bioinformatics is the identification of protein folds from sequence data. This can be regarded as a pattern recognition problem. In this paper we report the use of a melody generation software where the inputs are derived from calculations of evolutionary information, secondary structure, flexibility, hydropathy and solvent accessibility from multiple sequence alignment data. The melodies so generated are derived from the sequence, and by inference, of the fold, in ways that give each fold a sound representation that may facilitate analysis, recognition, or comparison with other sequences.

Folded Plate Structures as Building Envelopes

DEFF Research Database (Denmark)

Falk, Andreas; Buelow, Peter von; Kirkegaard, Poul Henning

2012-01-01

This paper treats applications of cross-laminated timber (CLT) in structural systems for folded façade solutions. Previous work on CLT-based systems for folded roofs has shown a widening range of structural possibilities to develop timber-based shells. Geometric and material properties play...... CLT-based systems, which are studied and analysed by using a combination of digital tools for structural and environmental design and analysis. The results show gainful, rational properties of folded systems and beneficial effects from an integration of architectural and environmental performance...... criteria in the design of CLT-based façades....

Mechanical Models of Fault-Related Folding

Energy Technology Data Exchange (ETDEWEB)

Johnson, A. M.

2003-01-09

The subject of the proposed research is fault-related folding and ground deformation. The results are relevant to oil-producing structures throughout the world, to understanding of damage that has been observed along and near earthquake ruptures, and to earthquake-producing structures in California and other tectonically-active areas. The objectives of the proposed research were to provide both a unified, mechanical infrastructure for studies of fault-related foldings and to present the results in computer programs that have graphical users interfaces (GUIs) so that structural geologists and geophysicists can model a wide variety of fault-related folds (FaRFs).

A Self-Assisting Protein Folding Model for Teaching Structural Molecular Biology.

Science.gov (United States)

Davenport, Jodi; Pique, Michael; Getzoff, Elizabeth; Huntoon, Jon; Gardner, Adam; Olson, Arthur

2017-04-04

Structural molecular biology is now becoming part of high school science curriculum thus posing a challenge for teachers who need to convey three-dimensional (3D) structures with conventional text and pictures. In many cases even interactive computer graphics does not go far enough to address these challenges. We have developed a flexible model of the polypeptide backbone using 3D printing technology. With this model we have produced a polypeptide assembly kit to create an idealized model of the Triosephosphate isomerase mutase enzyme (TIM), which forms a structure known as TIM barrel. This kit has been used in a laboratory practical where students perform a step-by-step investigation into the nature of protein folding, starting with the handedness of amino acids to the formation of secondary and tertiary structure. Based on the classroom evidence we collected, we conclude that these models are valuable and inexpensive resource for teaching structural molecular biology. Copyright © 2017 Elsevier Ltd. All rights reserved.

Carbon dioxide therapy and hyaluronic acid for cosmetic correction of the nasolabial folds.

Science.gov (United States)

Nisi, Giuseppe; Cuomo, Roberto; Brandi, Cesare; Grimaldi, Luca; Sisti, Andrea; D'Aniello, Carlo

2016-06-01

The main application of hyaluronic acid filling, in esthetic medicine, is the augmentation of soft tissues. The carbon dioxide therapy, instead, improves quality and elasticity of the dermis and increases the oxygen release to the tissue through an enhancing of the Bohr's effect. The aim of the study was to compare the efficacy, tolerability, and effect duration of hyaluronic acid fillers and the use of carbon dioxide therapy plus hyaluronic acid in the cosmetic correction of nasolabial folds. Forty healthy female patients received a blinded and randomized treatment on nasolabial folds (hyaluronic acid in group A and hyaluronic acid plus subcutaneous injections of carbon dioxide in group B) for cosmetic correction of the nasolabial folds. The results were evaluated by two blinded plastic surgeons after the implant (1 week, 4 and 6 months) using a 1-5 graduated scale (GAIS), and at the same time, each patient was asked to express her opinion about the cosmetic result. Any long-term adverse reaction was reported. The blinded evaluation at 4 and 6 months from the implant shows in all patients a maintenance of a good cosmetic result higher for the side treated with carbon dioxide therapy plus hyaluronic acid. At the control visit, 6 months after the treatment, the patients treated with hyaluronic acid plus carbon dioxide therapy maintain a satisfactory esthetic result while the nasolabial fold treated only with hyaluronic acid shows, in almost all patients, a come back to pretreatment appearance. © 2016 Wiley Periodicals, Inc.

Highly active bidirectional electron transfer by a self-assembled electroactive reduced-graphene-oxide-hybridized biofilm.

Science.gov (United States)

Yong, Yang-Chun; Yu, Yang-Yang; Zhang, Xinhai; Song, Hao

2014-04-22

Low extracellular electron transfer performance is often a bottleneck in developing high-performance bioelectrochemical systems. Herein, we show that the self-assembly of graphene oxide and Shewanella oneidensis MR-1 formed an electroactive, reduced-graphene-oxide-hybridized, three-dimensional macroporous biofilm, which enabled highly efficient bidirectional electron transfers between Shewanella and electrodes owing to high biomass incorporation and enhanced direct contact-based extracellular electron transfer. This 3D electroactive biofilm delivered a 25-fold increase in the outward current (oxidation current, electron flux from bacteria to electrodes) and 74-fold increase in the inward current (reduction current, electron flux from electrodes to bacteria) over that of the naturally occurring biofilms. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of translation profiles enhances protein expression and solubility.

Directory of Open Access Journals (Sweden)

Anne-Katrin Hess

Full Text Available mRNA is translated with a non-uniform speed that actively coordinates co-translational folding of protein domains. Using structure-based homology we identified the structural domains in epoxide hydrolases (EHs and introduced slow-translating codons to delineate the translation of single domains. These changes in translation speed dramatically improved the solubility of two EHs of metagenomic origin in Escherichia coli. Conversely, the importance of transient attenuation for the folding, and consequently solubility, of EH was evidenced with a member of the EH family from Agrobacterium radiobacter, which partitions in the soluble fraction when expressed in E. coli. Synonymous substitutions of codons shaping the slow-transiting regions to fast-translating codons render this protein insoluble. Furthermore, we show that low protein yield can be enhanced by decreasing the free folding energy of the initial 5'-coding region, which can disrupt mRNA secondary structure and enhance ribosomal loading. This study provides direct experimental evidence that mRNA is not a mere messenger for translation of codons into amino acids but bears an additional layer of information for folding, solubility and expression level of the encoded protein. Furthermore, it provides a general frame on how to modulate and fine-tune gene expression of a target protein.

Assembly factors for the membrane arm of human complex I.

Science.gov (United States)

Andrews, Byron; Carroll, Joe; Ding, Shujing; Fearnley, Ian M; Walker, John E

2013-11-19

Mitochondrial respiratory complex I is a product of both the nuclear and mitochondrial genomes. The integration of seven subunits encoded in mitochondrial DNA into the inner membrane, their association with 14 nuclear-encoded membrane subunits, the construction of the extrinsic arm from 23 additional nuclear-encoded proteins, iron-sulfur clusters, and flavin mononucleotide cofactor require the participation of assembly factors. Some are intrinsic to the complex, whereas others participate transiently. The suppression of the expression of the NDUFA11 subunit of complex I disrupted the assembly of the complex, and subcomplexes with masses of 550 and 815 kDa accumulated. Eight of the known extrinsic assembly factors plus a hydrophobic protein, C3orf1, were associated with the subcomplexes. The characteristics of C3orf1, of another assembly factor, TMEM126B, and of NDUFA11 suggest that they all participate in constructing the membrane arm of complex I.

Endogenous angiotensin II modulates nNOS expression in renovascular hypertension

Directory of Open Access Journals (Sweden)

T.M.C. Pereira

2009-07-01

Full Text Available Nitric oxide (NO influences renal blood flow mainly as a result of neuronal nitric oxide synthase (nNOS. Nevertheless, it is unclear how nNOS expression is modulated by endogenous angiotensin II, an inhibitor of NO function. We tested the hypothesis that the angiotensin II AT1 receptor and oxidative stress mediated by NADPH oxidase contribute to the modulation of renal nNOS expression in two-kidney, one-clip (2K1C hypertensive rats. Experiments were performed on male Wistar rats (150 to 170 g body weight divided into 2K1C (N = 19 and sham-operated (N = 19 groups. nNOS expression in kidneys of 2K1C hypertensive rats (N = 9 was compared by Western blotting to that of 2K1C rats treated with low doses of the AT1 antagonist losartan (10 mg·kg-1·day-1; N = 5 or the superoxide scavenger tempol (0.2 mmol·kg-1·day-1; N = 5, which still remain hypertensive. After 28 days, nNOS expression was significantly increased by 1.7-fold in the clipped kidneys of 2K1C rats and by 3-fold in the non-clipped kidneys of 2K1C rats compared with sham rats, but was normalized by losartan. With tempol treatment, nNOS expression increased 2-fold in the clipped kidneys and 1.4-fold in the non-clipped kidneys compared with sham rats. The changes in nNOS expression were not followed by changes in the enzyme activity, as measured indirectly by the cGMP method. In conclusion, AT1 receptors and oxidative stress seem to be primary stimuli for increased nNOS expression, but this up-regulation does not result in higher enzyme activity.

Coarsely resolved topography along protein folding pathways

Science.gov (United States)

Fernández, Ariel; Kostov, Konstantin S.; Berry, R. Stephen

2000-03-01

The kinetic data from the coarse representation of polypeptide torsional dynamics described in the preceding paper [Fernandez and Berry, J. Chem. Phys. 112, 5212 (2000), preceding paper] is inverted by using detailed balance to obtain a topographic description of the potential-energy surface (PES) along the dominant folding pathway of the bovine pancreatic trypsin inhibitor (BPTI). The topography is represented as a sequence of minima and effective saddle points. The dominant folding pathway displays an overall monotonic decrease in energy with a large number of staircaselike steps, a clear signature of a good structure-seeker. The diversity and availability of alternative folding pathways is analyzed in terms of the Shannon entropy σ(t) associated with the time-dependent probability distribution over the kinetic ensemble of contact patterns. Several stages in the folding process are evident. Initially misfolded states form and dismantle revealing no definite pattern in the topography and exhibiting high Shannon entropy. Passage down a sequence of staircase steps then leads to the formation of a nativelike intermediate, for which σ(t) is much lower and fairly constant. Finally, the structure of the intermediate is refined to produce the native state of BPTI. We also examine how different levels of tolerance to mismatches of side chain contacts influence the folding kinetics, the topography of the dominant folding pathway, and the Shannon entropy. This analysis yields upper and lower bounds of the frustration tolerance required for the expeditious and robust folding of BPTI.

Charge neutralization as the major factor for the assembly of nucleocapsid-like particles from C-terminal truncated hepatitis C virus core protein.

Science.gov (United States)

de Souza, Theo Luiz Ferraz; de Lima, Sheila Maria Barbosa; Braga, Vanessa L de Azevedo; Peabody, David S; Ferreira, Davis Fernandes; Bianconi, M Lucia; Gomes, Andre Marco de Oliveira; Silva, Jerson Lima; de Oliveira, Andréa Cheble

2016-01-01

Hepatitis C virus (HCV) core protein, in addition to its structural role to form the nucleocapsid assembly, plays a critical role in HCV pathogenesis by interfering in several cellular processes, including microRNA and mRNA homeostasis. The C-terminal truncated HCV core protein (C124) is intrinsically unstructured in solution and is able to interact with unspecific nucleic acids, in the micromolar range, and to assemble into nucleocapsid-like particles (NLPs) in vitro . The specificity and propensity of C124 to the assembly and its implications on HCV pathogenesis are not well understood. Spectroscopic techniques, transmission electron microscopy and calorimetry were used to better understand the propensity of C124 to fold or to multimerize into NLPs when subjected to different conditions or in the presence of unspecific nucleic acids of equivalent size to cellular microRNAs. The structural analysis indicated that C124 has low propensity to self-folding. On the other hand, for the first time, we show that C124, in the absence of nucleic acids, multimerizes into empty NLPs when subjected to a pH close to its isoelectric point (pH ≈ 12), indicating that assembly is mainly driven by charge neutralization. Isothermal calorimetry data showed that the assembly of NLPs promoted by nucleic acids is enthalpy driven. Additionally, data obtained from fluorescence correlation spectroscopy show that C124, in nanomolar range, was able to interact and to sequester a large number of short unspecific nucleic acids into NLPs. Together, our data showed that the charge neutralization is the major factor for the nucleocapsid-like particles assembly from C-terminal truncated HCV core protein. This finding suggests that HCV core protein may physically interact with unspecific cellular polyanions, which may correspond to microRNAs and mRNAs in a host cell infected by HCV, triggering their confinement into infectious particles.

Idiopathic unilateral vocal-fold paralysis in the adult.

Science.gov (United States)

Rubin, F; Villeneuve, A; Alciato, L; Slaïm, L; Bonfils, P; Laccourreye, O

2018-02-02

To analyze the characteristics of adult idiopathic unilateral vocal-fold paralysis. Retrospective study of diagnostic problems, clinical data and recovery in an inception cohort of 100 adult patients with idiopathic unilateral vocal-fold paralysis (Group A) and comparison with a cohort of 211 patients with isolated non-idiopathic non-traumatic unilateral vocal-fold paralysis (Group B). Diagnostic problems were noted in 24% of cases in Group A: eight patients with concomitant common upper aerodigestive tract infection, five patients with a concomitant condition liable to induce immunodepression and 11 patients in whom a malignant tumor occurred along the path of the ipsilateral vagus and inferior laryngeal nerves or in the ipsilateral paralyzed larynx. There was no recovery of vocal-fold motion beyond 51 months after onset of paralysis. The 5-year actuarial estimate for recovery differed significantly (Pvocal-fold paralysis. In non-traumatic vocal-fold paralysis in adult patients, without recovery of vocal-fold motion, a minimum three years' regular follow-up is recommended. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Single injection of basic fibroblast growth factor to treat severe vocal fold lesions and vocal fold paralysis.

Science.gov (United States)

Kanazawa, Takeharu; Komazawa, Daigo; Indo, Kanako; Akagi, Yusuke; Lee, Yogaku; Nakamura, Kazuhiro; Matsushima, Koji; Kunieda, Chikako; Misawa, Kiyoshi; Nishino, Hiroshi; Watanabe, Yusuke

2015-10-01

Severe vocal fold lesions such as vocal fold sulcus, scars, and atrophy induce a communication disorder due to severe hoarseness, but a treatment has not been established. Basic fibroblast growth factor (bFGF) therapies by either four-time repeated local injections or regenerative surgery for vocal fold scar and sulcus have previously been reported, and favorable outcomes have been observed. In this study, we modified bFGF therapy using a single of bFGF injection, which may potentially be used in office procedures. Retrospective chart review. Five cases of vocal fold sulcus, six cases of scars, seven cases of paralysis, and 17 cases of atrophy were treated by a local injection of bFGF. The injection regimen involved injecting 50 µg of bFGF dissolved in 0.5 mL saline only once into the superficial lamina propria using a 23-gauge injection needle. Two months to 3 months after the injection, phonological outcomes were evaluated. The maximum phonation time (MPT), mean airflow rate, pitch range, speech fundamental frequency, jitter, and voice handicap index improved significantly after the bFGF injection. Furthermore, improvement in the MPT was significantly greater in patients with (in increasing order) vocal fold atrophy, scar, and paralysis. The improvement in the MPT among all patients was significantly correlated with age; the MPT improved more greatly in younger patients. Regenerative treatments by bFGF injection—even a single injection—effectively improve vocal function in vocal fold lesions. 4 © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

A comparison of RNA folding measures

DEFF Research Database (Denmark)

Freyhult, E.; Gardner, P. P.; Moulton, V.

2005-01-01

the behaviour of these measures over a large range of Rfam ncRNA families. Such measures can be useful in, for example, identifying novel ncRNAs, and indicating the presence of alternate RNA foldings. Results Our analysis shows that ncRNAs, but not mRNAs, in general have lower minimal free energy (MFE) than....... Conclusion Due to the correlations between the different measures we find that it is sufficient to use only two of them in RNA folding studies, one to test if the sequence in question has lower energy than a random sequence with the same dinucleotide frequency (the Z-score) and the other to see......Background In the last few decades there has been a great deal of discussion concerning whether or not noncoding RNA sequences (ncRNAs) fold in a more well-defined manner than random sequences. In this paper, we investigate several existing measures for how well an RNA sequence folds, and compare...

The rapid manufacture of uniform composite multicellular-biomaterial micropellets, their assembly into macroscopic organized tissues, and potential applications in cartilage tissue engineering.

Science.gov (United States)

Babur, Betul Kul; Kabiri, Mahboubeh; Klein, Travis Jacob; Lott, William B; Doran, Michael Robert

2015-01-01

We and others have published on the rapid manufacture of micropellet tissues, typically formed from 100-500 cells each. The micropellet geometry enhances cellular biological properties, and in many cases the micropellets can subsequently be utilized as building blocks to assemble complex macrotissues. Generally, micropellets are formed from cells alone, however when replicating matrix-rich tissues such as cartilage it would be ideal if matrix or biomaterials supplements could be incorporated directly into the micropellet during the manufacturing process. Herein we describe a method to efficiently incorporate donor cartilage matrix into tissue engineered cartilage micropellets. We lyophilized bovine cartilage matrix, and then shattered it into microscopic pieces having average dimensions manufacture of thousands of replica composite micropellets, with each micropellet having a material/CD core and a cellular surface. This micropellet organization enabled the rapid bulking up of the micropellet core matrix content, and left an adhesive cellular outer surface. This morphological organization enabled the ready assembly of the composite micropellets into macroscopic tissues. Generically, this is a versatile method that enables the rapid and uniform integration of biomaterials into multicellular micropellets that can then be used as tissue building blocks. In this study, the addition of CD resulted in an approximate 8-fold volume increase in the micropellets, with the donor matrix functioning to contribute to an increase in total cartilage matrix content. Composite micropellets were readily assembled into macroscopic cartilage tissues; the incorporation of CD enhanced tissue size and matrix content, but did not enhance chondrogenic gene expression.

The Ventricular-Fold Dynamics in Human Phonation

OpenAIRE

Bailly , Lucie; Henrich Bernardoni , Nathalie; Müller , Frank; Rohlfs , Anna-Katharina; Hess , Markus

2014-01-01

International audience; Purpose: In this study, the authors aimed (a) to provide a classification of the ventricular-fold dynamics during voicing, (b) to study the aerodynamic impact of these motions on vocal-fold vibrations, and (c) to assess whether ventricularfold oscillations could be sustained by aerodynamic coupling with the vocal folds. Method: A 72-sample database of vocal gestures accompanying different acoustical events comprised highspeed cinematographic, audio, and electroglottogr...

Single-Chain Folding of Synthetic Polymers: A Critical Update.

Science.gov (United States)

Altintas, Ozcan; Barner-Kowollik, Christopher

2015-11-23

The current contribution serves as a critical update to a previous feature article from us (Macromol. Rapid Commun. 2012, 33, 958-971), and highlights the latest advances in the preparation of single chain polymeric nanoparticles and initial-yet promising-attempts towards mimicking the structure of natural biomacromolecules via single-chain folding of well-defined linear polymers via so-called single chain selective point folding and repeat unit folding. The contribution covers selected examples from the literature published up to ca. September 2015. Our aim is not to provide an exhaustive review but rather highlight a selection of new and exciting examples for single-chain folding based on advanced macromolecular precision chemistry. Initially, the discussion focuses on the synthesis and characterization of single-chain folded structures via selective point folding. The second part of the feature article addresses the folding of well-defined single-chain polymers by means of repeat unit folding. The current state of the art in the field of single-chain folding indicates that repeat unit folding-driven nanoparticle preparation is well-advanced, while initial encouraging steps towards building selective point folding systems have been taken. In addition, a summary of the-in our view-open key questions is provided that may guide future biomimetic design efforts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Robotically Assembled Aerospace Structures: Digital Material Assembly using a Gantry-Type Assembler

Science.gov (United States)

Trinh, Greenfield; Copplestone, Grace; O'Connor, Molly; Hu, Steven; Nowak, Sebastian; Cheung, Kenneth; Jenett, Benjamin; Cellucci, Daniel

2017-01-01

This paper evaluates the development of automated assembly techniques for discrete lattice structures using a multi-axis gantry type CNC machine. These lattices are made of discrete components called "digital materials." We present the development of a specialized end effector that works in conjunction with the CNC machine to assemble these lattices. With this configuration we are able to place voxels at a rate of 1.5 per minute. The scalability of digital material structures due to the incremental modular assembly is one of its key traits and an important metric of interest. We investigate the build times of a 5x5 beam structure on the scale of 1 meter (325 parts), 10 meters (3,250 parts), and 30 meters (9,750 parts). Utilizing the current configuration with a single end effector, performing serial assembly with a globally fixed feed station at the edge of the build volume, the build time increases according to a scaling law of n4, where n is the build scale. Build times can be reduced significantly by integrating feed systems into the gantry itself, resulting in a scaling law of n3. A completely serial assembly process will encounter time limitations as build scale increases. Automated assembly for digital materials can assemble high performance structures from discrete parts, and techniques such as built in feed systems, parallelization, and optimization of the fastening process will yield much higher throughput.

Adipose-Derived Mesenchymal Stem Cells in the Regeneration of Vocal Folds: A Study on a Chronic Vocal Fold Scar

Directory of Open Access Journals (Sweden)

Angelou Valerie

2016-01-01

Full Text Available Background. The aim of the study was to assess the histological effects of autologous infusion of adipose-derived stem cells (ADSC on a chronic vocal fold scar in a rabbit model as compared to an untreated scar as well as in injection of hyaluronic acid. Study Design. Animal experiment. Method. We used 74 New Zealand rabbits. Sixteen of them were used as control/normal group. We created a bilateral vocal fold wound in the remaining 58 rabbits. After 18 months we separated our population into three groups. The first group served as control/scarred group. The second one was injected with hyaluronic acid in the vocal folds, and the third received an autologous adipose-derived stem cell infusion in the scarred vocal folds (ADSC group. We measured the variation of thickness of the lamina propria of the vocal folds and analyzed histopathologic changes in each group after three months. Results. The thickness of the lamina propria was significantly reduced in the group that received the ADSC injection, as compared to the normal/scarred group. The collagen deposition, the hyaluronic acid, the elastin levels, and the organization of elastic fibers tend to return to normal after the injection of ADSC. Conclusions. Autologous injection of adipose-derived stem cells on a vocal fold chronic scar enhanced the healing of the vocal folds and the reduction of the scar tissue, even when compared to other treatments.

Adipose-Derived Mesenchymal Stem Cells in the Regeneration of Vocal Folds: A Study on a Chronic Vocal Fold Scar

Science.gov (United States)

Vassiliki, Kalodimou; Irini, Messini; Nikolaos, Psychalakis; Karampela, Eleftheria; Apostolos, Papalois

2016-01-01

Background. The aim of the study was to assess the histological effects of autologous infusion of adipose-derived stem cells (ADSC) on a chronic vocal fold scar in a rabbit model as compared to an untreated scar as well as in injection of hyaluronic acid. Study Design. Animal experiment. Method. We used 74 New Zealand rabbits. Sixteen of them were used as control/normal group. We created a bilateral vocal fold wound in the remaining 58 rabbits. After 18 months we separated our population into three groups. The first group served as control/scarred group. The second one was injected with hyaluronic acid in the vocal folds, and the third received an autologous adipose-derived stem cell infusion in the scarred vocal folds (ADSC group). We measured the variation of thickness of the lamina propria of the vocal folds and analyzed histopathologic changes in each group after three months. Results. The thickness of the lamina propria was significantly reduced in the group that received the ADSC injection, as compared to the normal/scarred group. The collagen deposition, the hyaluronic acid, the elastin levels, and the organization of elastic fibers tend to return to normal after the injection of ADSC. Conclusions. Autologous injection of adipose-derived stem cells on a vocal fold chronic scar enhanced the healing of the vocal folds and the reduction of the scar tissue, even when compared to other treatments. PMID:26933440

Effect of Vocal Fold Medialization on Dysphagia in Patients with Unilateral Vocal Fold Immobility.

Science.gov (United States)

Cates, Daniel J; Venkatesan, Naren N; Strong, Brandon; Kuhn, Maggie A; Belafsky, Peter C

2016-09-01

The effect of vocal fold medialization (VFM) on vocal improvement in persons with unilateral vocal fold immobility (UVFI) is well established. The effect of VFM on the symptom of dysphagia is uncertain. The purpose of this study is to evaluate dysphagia symptoms in patients with UVFI pre- and post-VFM. Case series with chart review. Academic tertiary care medical center. The charts of 44 persons with UVFI who underwent VFM between June 1, 2013, and December 31, 2014, were abstracted from a prospectively maintained database at the University of California, Davis, Voice and Swallowing Center. Patient demographics, indications, and type of surgical procedure were recorded. Self-reported swallowing impairment was assessed with the validated 10-item Eating Assessment Tool (EAT-10) before and after surgery. A paired samples t test was used to compare pre- and postmedialization EAT-10 scores. Forty-four patients met criteria and underwent either vocal fold injection (73%) or thyroplasty (27%). Etiologies of vocal fold paralysis were iatrogenic (55%), idiopathic (29%), benign or malignant neoplastic (9%), traumatic (5%), or related to the late effects of radiation (2%). EAT-10 (mean ± SD) scores improved from 12.2 ± 11.1 to 7.7 ± 7.2 after medialization (P dysphagia and report significant improvement in swallowing symptoms following VFM. The symptomatic improvement appears to be durable over time. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

Self-assembly of colloids with magnetic caps

Energy Technology Data Exchange (ETDEWEB)

Novak, E.V., E-mail: ekaterina.novak@urfu.ru [Ural Federal University, Lenin Av. 51, Ekaterinburg (Russian Federation); Kantorovich, S.S. [Ural Federal University, Lenin Av. 51, Ekaterinburg (Russian Federation); University of Vienna, Sensengasse 8, Vienna (Austria)

2017-06-01

In our earlier work (Steinbach et al., 2016 ) we investigated a homogeneous system of magnetically capped colloidal particles that self-assembled via two structural patterns of different symmetry. The particles could form a compact, equilateral triangle with a three-fold rotational symmetry and zero dipole moment and a staggered chain with mirror symmetry with a net magnetisation perpendicular to the chain. The system exhibited a bistability already in clusters of three particles. Based on observations of a real magnetic particles system, analytical calculations and molecular dynamics simulations, it has been shown that the bistability is a result of an anisotropic magnetisation distribution with rotational symmetry inside the particles. The present study is a logical extension of the above research and forms a preparatory stage for the study of a self-assembly of such magnetic particles under the influence of an external magnetic field. Since the magnetic field is only an additive contribution to the total ground state energy, we can study the interparticle interaction energies of candidate ground state structures based on the field-free terms. - Highlights: • Analytical calculations of the energies of ground state candidates for colloids with magnetic caps. • Computer simulations confirmed the theoretical model. • The structural transition between ground states was found.

Nomenclature proposal to describe vocal fold motion impairment

NARCIS (Netherlands)

Rosen, Clark A.; Mau, Ted; Remacle, Marc; Hess, Markus; Eckel, Hans E.; Young, VyVy N.; Hantzakos, Anastasios; Yung, Katherine C.; Dikkers, Frederik G.

2016-01-01

The terms used to describe vocal fold motion impairment are confusing and not standardized. This results in a failure to communicate accurately and to major limitations of interpreting research studies involving vocal fold impairment. We propose standard nomenclature for reporting vocal fold

Nomenclature proposal to describe vocal fold motion impairment

NARCIS (Netherlands)

Rosen, Clark A.; Mau, Ted; Remacle, Marc; Hess, Markus; Eckel, Hans E.; Young, VyVy N.; Hantzakos, Anastasios; Yung, Katherine C.; Dikkers, Frederik G.

The terms used to describe vocal fold motion impairment are confusing and not standardized. This results in a failure to communicate accurately and to major limitations of interpreting research studies involving vocal fold impairment. We propose standard nomenclature for reporting vocal fold

Curved Folded Plate Timber Structures

OpenAIRE

Buri, Hans Ulrich; Stotz, Ivo; Weinand, Yves

2011-01-01

This work investigates the development of a Curved Origami Prototype made with timber panels. In the last fifteen years the timber industry has developed new, large size, timber panels. Composition and dimensions of these panels and the possibility of milling them with Computer Numerical Controlled machines shows great potential for folded plate structures. To generate the form of these structures we were inspired by Origami, the Japanese art of paper folding. Common paper tessellations are c...

Dysphonia and vocal fold telangiectasia in hereditary hemorrhagic telangiectasia.

Science.gov (United States)

Chang, Joseph; Yung, Katherine C

2014-11-01

This case report is the first documentation of dysphonia and vocal fold telangiectasia as a complication of hereditary hemorrhagic telangiectasia (HHT). Case report of a 40-year-old man with HHT presenting with 2 years of worsening hoarseness. Hoarseness corresponded with a period of anticoagulation. Endoscopy revealed vocal fold scarring, vocal fold telangiectasias, and plica ventricular is suggestive of previous submucosal vocal fold hemorrhage and subsequent counterproductive compensation with ventricular phonation. Hereditary hemorrhagic telangiectasia may present as dysphonia with vocal fold telangiectasias and place patients at risk of vocal fold hemorrhage. © The Author(s) 2014.

Accurately controlled sequential self-folding structures by polystyrene film

Science.gov (United States)

Deng, Dongping; Yang, Yang; Chen, Yong; Lan, Xing; Tice, Jesse

2017-08-01

Four-dimensional (4D) printing overcomes the traditional fabrication limitations by designing heterogeneous materials to enable the printed structures evolve over time (the fourth dimension) under external stimuli. Here, we present a simple 4D printing of self-folding structures that can be sequentially and accurately folded. When heated above their glass transition temperature pre-strained polystyrene films shrink along the XY plane. In our process silver ink traces printed on the film are used to provide heat stimuli by conducting current to trigger the self-folding behavior. The parameters affecting the folding process are studied and discussed. Sequential folding and accurately controlled folding angles are achieved by using printed ink traces and angle lock design. Theoretical analyses are done to guide the design of the folding processes. Programmable structures such as a lock and a three-dimensional antenna are achieved to test the feasibility and potential applications of this method. These self-folding structures change their shapes after fabrication under controlled stimuli (electric current) and have potential applications in the fields of electronics, consumer devices, and robotics. Our design and fabrication method provides an easy way by using silver ink printed on polystyrene films to 4D print self-folding structures for electrically induced sequential folding with angular control.

Identification of distinct layers within the stratified squamous epithelium of the adult human true vocal fold.

Science.gov (United States)

Dowdall, Jayme R; Sadow, Peter M; Hartnick, Christopher; Vinarsky, Vladimir; Mou, Hongmei; Zhao, Rui; Song, Phillip C; Franco, Ramon A; Rajagopal, Jayaraj

2015-09-01

A precise molecular schema for classifying the different cell types of the normal human vocal fold epithelium is lacking. We hypothesize that the true vocal fold epithelium has a cellular architecture and organization similar to that of other stratified squamous epithelia including the skin, cornea, oral mucosa, and esophagus. In analogy to disorders of the skin and gastrointestinal tract, a molecular definition of the normal cell types within the human vocal fold epithelium and a description of their geometric relationships should serve as a foundation for characterizing cellular changes associated with metaplasia, dysplasia, and cancer. Qualitative study with adult human larynges. Histologic sections of normal human laryngeal tissue were analyzed for morphology (hematoxylin and eosin) and immunohistochemical protein expression profile, including cytokeratins (CK13 and CK14), cornified envelope proteins (involucrin), basal cells (NGFR/p75), and proliferation markers (Ki67). We demonstrated that three distinct cell strata with unique marker profiles are present within the stratified squamous epithelium of the true vocal fold. We used these definitions to establish that cell proliferation is restricted to certain cell types and layers within the epithelium. These distinct cell types are reproducible across five normal adult larynges. We have established that three layers of cells are present within the normal adult stratified squamous epithelium of the true vocal fold. Furthermore, replicating cell populations are largely restricted to the parabasal strata within the epithelium. This delineation of distinct cell populations will facilitate future studies of vocal fold regeneration and cancer. N/A. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

Bacteriophage Assembly

Directory of Open Access Journals (Sweden)

Anastasia A. Aksyuk

2011-02-01

Full Text Available Bacteriophages have been a model system to study assembly processes for over half a century. Formation of infectious phage particles involves specific protein-protein and protein-nucleic acid interactions, as well as large conformational changes of assembly precursors. The sequence and molecular mechanisms of phage assembly have been elucidated by a variety of methods. Differences and similarities of assembly processes in several different groups of bacteriophages are discussed in this review. The general principles of phage assembly are applicable to many macromolecular complexes.

Unraveling metamaterial properties in zigzag-base folded sheets.

Science.gov (United States)

Eidini, Maryam; Paulino, Glaucio H

2015-09-01

Creating complex spatial objects from a flat sheet of material using origami folding techniques has attracted attention in science and engineering. In the present work, we use the geometric properties of partially folded zigzag strips to better describe the kinematics of known zigzag/herringbone-base folded sheet metamaterials such as Miura-ori. Inspired by the kinematics of a one-degree of freedom zigzag strip, we introduce a class of cellular folded mechanical metamaterials comprising different scales of zigzag strips. This class of patterns combines origami folding techniques with kirigami. Using analytical and numerical models, we study the key mechanical properties of the folded materials. We show that our class of patterns, by expanding on the design space of Miura-ori, is appropriate for a wide range of applications from mechanical metamaterials to deployable structures at small and large scales. We further show that, depending on the geometry, these materials exhibit either negative or positive in-plane Poisson's ratios. By introducing a class of zigzag-base materials in the current study, we unify the concept of in-plane Poisson's ratio for similar materials in the literature and extend it to the class of zigzag-base folded sheet materials.

Accurate, model-based tuning of synthetic gene expression using introns in S. cerevisiae.

Directory of Open Access Journals (Sweden)

Ido Yofe

2014-06-01

Full Text Available Introns are key regulators of eukaryotic gene expression and present a potentially powerful tool for the design of synthetic eukaryotic gene expression systems. However, intronic control over gene expression is governed by a multitude of complex, incompletely understood, regulatory mechanisms. Despite this lack of detailed mechanistic understanding, here we show how a relatively simple model enables accurate and predictable tuning of synthetic gene expression system in yeast using several predictive intron features such as transcript folding and sequence motifs. Using only natural Saccharomyces cerevisiae introns as regulators, we demonstrate fine and accurate control over gene expression spanning a 100 fold expression range. These results broaden the engineering toolbox of synthetic gene expression systems and provide a framework in which precise and robust tuning of gene expression is accomplished.

RNAslider: a faster engine for consecutive windows folding and its application to the analysis of genomic folding asymmetry

Directory of Open Access Journals (Sweden)

Ziv-Ukelson Michal

2009-03-01

Full Text Available Abstract Background Scanning large genomes with a sliding window in search of locally stable RNA structures is a well motivated problem in bioinformatics. Given a predefined window size L and an RNA sequence S of size N (L 3 by applying any of the classical cubic-time RNA folding algorithms to each of the N-L windows of size L. Recently an O(NL2 solution for this problem has been described. Results Here, we describe and implement an O(NLψ(L engine for the consecutive windows folding problem, where ψ(L is shown to converge to O(1 under the assumption of a standard probabilistic polymer folding model, yielding an O(L speedup which is experimentally confirmed. Using this tool, we note an intriguing directionality (5'-3' vs. 3'-5' folding bias, i.e. that the minimal free energy (MFE of folding is higher in the native direction of the DNA than in the reverse direction of various genomic regions in several organisms including regions of the genomes that do not encode proteins or ncRNA. This bias largely emerges from the genomic dinucleotide bias which affects the MFE, however we see some variations in the folding bias in the different genomic regions when normalized to the dinucleotide bias. We also present results from calculating the MFE landscape of a mouse chromosome 1, characterizing the MFE of the long ncRNA molecules that reside in this chromosome. Conclusion The efficient consecutive windows folding engine described in this paper allows for genome wide scans for ncRNA molecules as well as large-scale statistics. This is implemented here as a software tool, called RNAslider, and applied to the scanning of long chromosomes, leading to the observation of features that are visible only on a large scale.

DNA Assembly in 3D Printed Fluidics (Open Access, Publisher’s Version)

Science.gov (United States)

2015-12-30

millifluidics to mix linear double stranded DNA with enzymes to assemble plasmids via Golden Gate biochemistry . The assembly reac- tions occurred at...used, a constitutively expressed yellow fluorescent protein (YFP) reporter, and a plasmid backbone containing an ampicillin selection marker ( AMP ) and...proof-of- principle that 3D printed devices can adequately mix the Golden Gate enzymes and DNA and that the Golden Gate biochemistry proceeds