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Sample records for platform probing cytoskeleton

  1. Computational analysis of the tether-pulling experiment to probe plasma membrane-cytoskeleton interaction in cells

    Science.gov (United States)

    Schumacher, Kristopher R.; Popel, Aleksander S.; Anvari, Bahman; Brownell, William E.; Spector, Alexander A.

    2009-10-01

    Tethers are thin membrane tubes that can be formed when relatively small and localized forces are applied to cellular membranes and lipid bilayers. Tether pulling experiments have been used to better understand the fine membrane properties. These include the interaction between the plasma membrane and the underlying cytoskeleton, which is an important factor affecting membrane mechanics. We use a computational method aimed at the interpretation and design of tether pulling experiments in cells with a strong membrane-cytoskeleton attachment. In our model, we take into account the detailed information in the topology of bonds connecting the plasma membrane and the cytoskeleton. We compute the force-dependent piecewise membrane deflection and bending as well as modes of stored energy in three major regions of the system: body of the tether, membrane-cytoskeleton attachment zone, and the transition zone between the two. We apply our method to three cells: cochlear outer hair cells (OHCs), human embryonic kidney (HEK) cells, and Chinese hamster ovary (CHO) cells. OHCs have a special system of pillars connecting the membrane and the cytoskeleton, and HEK and CHO cells have the membrane-cytoskeleton adhesion arrangement via bonds (e.g., PIP2), which is common to many other cells. We also present a validation of our model by using experimental data on CHO and HEK cells. The proposed method can be an effective tool in the analyses of experiments to probe the properties of cellular membranes.

  2. Europa Science Platforms and Kinetic Energy Probes

    Science.gov (United States)

    Hays, C. C.; Klein, G. A.

    2003-01-01

    This presentation will outline a proposed mission for the Jupiter Icy Moons Orbiter (JIMO). The mission outlined will concentrate on an examination of Europa. Some of the primary science goals for the JIMO mission are: 1) to answer broad science questions, 2) improved knowledge of Jovian system; specifically, lunar geological and geophysical properties, 3) chemical composition of Jovian lunar surfaces and subterranean matter, and 4) the search for life. In order to address these issues, the experiment proposed here will deploy orbiting, surface, and subterranean science platforms.

  3. A ratiometric fluorescent probe for gasotransmitter hydrogen sulfide based on a coumarin-benzopyrylium platform.

    Science.gov (United States)

    Duan, Yu-Wei; Yang, Xiao-Feng; Zhong, Yaogang; Guo, Yuan; Li, Zheng; Li, Hua

    2015-02-15

    A ratiometric fluorescent probe for H2S was developed based on a coumarin- benzopyrylium platform. The ratiometric sensing is realized by a selective conversion of acyl azide to the corresponding amide, which subsequently undergoes an intramolecular spirocyclization to alter the large π-conjugated system of CB fluorophore. Compared with the traditional azide-based H2S probes, the proposed probe utilizes the acyl azide as the recognition moiety and exhibits a rapid response (∼1min) towards H2S, which is superior to most of the azide-based H2S probes. Preliminary fluorescence imaging experiments show that probe 1 has potential to track H2S in living cells.

  4. Design and evaluation of Actichip, a thematic microarray for the study of the actin cytoskeleton

    Directory of Open Access Journals (Sweden)

    Chalmel Frédéric

    2007-08-01

    Full Text Available Abstract Background The actin cytoskeleton plays a crucial role in supporting and regulating numerous cellular processes. Mutations or alterations in the expression levels affecting the actin cytoskeleton system or related regulatory mechanisms are often associated with complex diseases such as cancer. Understanding how qualitative or quantitative changes in expression of the set of actin cytoskeleton genes are integrated to control actin dynamics and organisation is currently a challenge and should provide insights in identifying potential targets for drug discovery. Here we report the development of a dedicated microarray, the Actichip, containing 60-mer oligonucleotide probes for 327 genes selected for transcriptome analysis of the human actin cytoskeleton. Results Genomic data and sequence analysis features were retrieved from GenBank and stored in an integrative database called Actinome. From these data, probes were designed using a home-made program (CADO4MI allowing sequence refinement and improved probe specificity by combining the complementary information recovered from the UniGene and RefSeq databases. Actichip performance was analysed by hybridisation with RNAs extracted from epithelial MCF-7 cells and human skeletal muscle. Using thoroughly standardised procedures, we obtained microarray images with excellent quality resulting in high data reproducibility. Actichip displayed a large dynamic range extending over three logs with a limit of sensitivity between one and ten copies of transcript per cell. The array allowed accurate detection of small changes in gene expression and reliable classification of samples based on the expression profiles of tissue-specific genes. When compared to two other oligonucleotide microarray platforms, Actichip showed similar sensitivity and concordant expression ratios. Moreover, Actichip was able to discriminate the highly similar actin isoforms whereas the two other platforms did not. Conclusion Our

  5. A broadband proton backlighting platform to probe shock propagation in low-density systems

    Science.gov (United States)

    Sio, H.; Hua, R.; Ping, Y.; McGuffey, C.; Beg, F.; Heeter, R.; Li, C. K.; Petrasso, R. D.; Collins, G. W.

    2017-01-01

    A proton backlighting platform has been developed for the study of strong shock propagation in low-density systems in planar geometry. Electric fields at the converging shock front in inertial confinement fusion implosions have been previously observed, demonstrating the presence of—and the need to understand—strong electric fields not modeled in standard radiation-hydrodynamic simulations. In this planar configuration, long-pulse ultraviolet lasers are used to drive a strong shock into a gas-cell target, while a short-pulse proton backlighter side-on radiographs the shock propagation. The capabilities of the platform are presented here. Future experiments will vary shock strength and gas fill, to probe shock conditions at different Z and Te.

  6. Application of Goldmag immune probe in timely detection of syphilis based on GIS platform.

    Science.gov (United States)

    Tang, Zhong; Liang, Zhisheng; Nong, Yi; Wu, Xiaochun; Luo, Hui; Gao, Kun

    2017-05-01

    The purpose of this study was to apply goldmag immunoprobes into establishment of nanoparticles-based colorimetric assay as well as construction of immunochromatography quantitative and qualitative system by exploring point-of-care testing of syphilis with goldmag particles carrier-based immunoprobe and analysis of spatial data of Geographic Information System (GIS) platform. Goat anti-rabbit immunoglobulin G (IgG) was coupled on the surface of modified nanoparticles, taking N-(3-dimethylaminopropyl)-N'-ethyl-carbodiimide as the connector. Then the nanoparticles were used for colorimetric detection of goat-anti-rabbit IgG in liquid phase system. Based on the analysis of spatial data in GIS platform, we found the probe constructed based on MUA-Fe304/Au nanoparticles responded more sensitive to detection objects compared with the probe designed based on PAA-Fe3O4/Au nanoparticles, and its reaction rate constant was two times that of PAA-Fe3O4/Au nanoparticles based goldmag immunoprobe. Goldmag particles not only can be coupled with biomolecules such as antibody/antigen and glycoprotein but also possess superparamagnetism.

  7. Spatial and temporal dynamics of receptor for advanced glycation endproducts, integrins, and actin cytoskeleton as probed with fluorescence-based imaging techniques

    Energy Technology Data Exchange (ETDEWEB)

    Syed, Aleem [Iowa State Univ., Ames, IA (United States)

    2016-01-01

    Systematic spatial and temporal fluctuations are a fundamental part of any biological process. For example, lateral diffusion of membrane proteins is one of the key mechanisms in their cellular function. Lateral diffusion governs how membrane proteins interact with intracellular, transmembrane, and extracellular components to achieve their function. Herein, fluorescence-based techniques are used to elucidate the dynamics of receptor for advanced glycation end-products (RAGE) and integrin membrane proteins. RAGE is a transmembrane protein that is being used as a biomarker for various diseases. RAGE dependent signaling in numerous pathological conditions is well studied. However, RAGE lateral diffusion in the cell membrane is poorly understood. For this purpose, effect of cholesterol, cytoskeleton dynamics, and presence of ligand on RAGE lateral diffusion is investigated.

  8. A platform for in-situ multi-probe electronic measurements and modification of nanodevices inside a transmission electron microscope

    Science.gov (United States)

    Xu, T. T.; Ning, Z. Y.; Shi, T. W.; Fu, M. Q.; Wang, J. Y.; Chen, Q.

    2014-06-01

    We developed a new platform that enables in-situ four-probe electronic measurements, in-situ three-probe field-effect measurements, nanomanipulation, and in-situ modification of nanodevices inside a transmission electron microscope (TEM). The platform includes a specially designed chip-holder and a silicon (Si) chip with suspended metal electrodes. The chip-holder can hold one Si chip with a size up to 3 mm × 3 mm and provides four electrical connections that can be connected to the micrometer-sized electrodes on the Si chip by wire-bonding. The other side of the electrical connections on the chip-holder is connected to the electronic instruments outside the TEM through a commercial Nanofactory SPM-TEM holder. The Si chip with suspended metal electrodes on one of its edges was fabricated by lithography and wet etching. Carbon nanotubes (CNTs), InAs nanowires, and tungsten disulfide nanowires were placed to stride over and connect to the suspended electrodes on the Si chip by nanomanipulations inside a scanning electron microscope (SEM). By using the platform, I-V curves of an individual single-walled CNT connecting to four electrodes were in-situ measured between any two of the four suspended electrodes, and a high-resolution TEM image of the same CNT was obtained. Furthermore, four-terminal I-V measurement on an InAs nanowire was achieved on this platform, and with a movable probe used as a gate electrode, field-effect measurement on the same InAs nanowire device was accomplished in SEM. In addition, by using the movable probe on the SPM-TEM holder, we could further in-situ modify nanomaterial and nanodevices. The present work demonstrates a method that allows a direct correlation between the atomic-level structure and the electronic property of nanomaterials or nanodevices whose structure can be further modified in-situ.

  9. Paper based colorimetric biosensing platform utilizing cross-linked siloxane as probe.

    Science.gov (United States)

    Zhou, Miao; Yang, Minghui; Zhou, Feimeng

    2014-05-15

    Paper based colorimetric biosensing platform utilizing cross-linked siloxane 3-aminopropyltriethoxysilane (APTMS) as probe was developed for the detection of a broad range of targets including H2O2, glucose and protein biomarker. APTMS was extensively used for the modification of filter papers to develop paper based analytical devices. We discovered when APTMS was cross-linked with glutaraldehyde (GA), the resulting complex (APTMS-GA) displays brick-red color, and a visual color change was observed when the complex reacted with H2O2. By integrating the APTMS-GA complex with filter paper, the modified paper enables quantitative detection of H2O2 through the monitoring of the color intensity change of the paper via software Image J. Then, with the immobilization of glucose oxidase (GOx) onto the modified paper, glucose can be detected through the detection of enzymatically generated H2O2. For protein biomarker prostate specific antigen (PSA) assay, we immobilized capture, not captured anti-PSA antibody (Ab1) onto the paper surface and using GOx modified gold nanorod (GNR) as detection anti-PSA antibody (Ab2) label. The detection of PSA was also achieved via the liberated H2O2 when the GOx label reacted with glucose. The results demonstrated the possibility of this paper based sensor for the detection of different analytes with wide linear range. The low cost and simplicity of this paper based sensor could be developed for "point-of-care" analysis and find wide application in different areas.

  10. Cytoskeleton and Cell Motility

    CERN Document Server

    Risler, Thomas

    2011-01-01

    The present article is an invited contribution to the Encyclopedia of Complexity and System Science, Robert A. Meyers Ed., Springer New York (2009). It is a review of the biophysical mechanisms that underly cell motility. It mainly focuses on the eukaryotic cytoskeleton and cell-motility mechanisms. Bacterial motility as well as the composition of the prokaryotic cytoskeleton is only briefly mentioned. The article is organized as follows. In Section III, I first present an overview of the diversity of cellular motility mechanisms, which might at first glance be categorized into two different types of behaviors, namely "swimming" and "crawling". Intracellular transport, mitosis - or cell division - as well as other extensions of cell motility that rely on the same essential machinery are briefly sketched. In Section IV, I introduce the molecular machinery that underlies cell motility - the cytoskeleton - as well as its interactions with the external environment of the cell and its main regulatory pathways. Sec...

  11. Reactive Microcontact Printing of DNA Probes on (DMA-NAS-MAPS) Copolymer-Coated Substrates for Efficient Hybridization Platforms.

    Science.gov (United States)

    Castagna, Rossella; Bertucci, Alessandro; Prasetyanto, Eko Adi; Monticelli, Marco; Conca, Dario Valter; Massetti, Matteo; Sharma, Parikshit Pratim; Damin, Francesco; Chiari, Marcella; De Cola, Luisa; Bertacco, Riccardo

    2016-04-05

    High-performing hybridization platforms fabricated by reactive microcontact printing of DNA probes are presented. Multishaped PDMS molds are used to covalently bind oligonucleotides over a functional copolymer (DMA-NAS-MAPS) surface. Printed structures with minimum width of about 1.5 μm, spaced by 10 μm, are demonstrated, with edge corrugation lower than 300 nm. The quantification of the immobilized surface probes via fluorescence imaging gives a remarkable concentration of 3.3 × 10(3) oligonucleotides/μm(2), almost totally active when used as probes in DNA-DNA hybridization assays. Indeed, fluorescence and atomic force microscopy show a 95% efficiency in target binding and uniform DNA hybridization over printed areas.

  12. Cytoskeleton - Methods and Protocols

    Directory of Open Access Journals (Sweden)

    CarloAlberto Redi

    2010-03-01

    Full Text Available Cytoskeleton - Methods and ProtocolsSecond edition, 2010; Ray H. Gavin (Ed; Springer Protocols methods in molecular biology, vol. 586 Humana press, Totowa, New Jersey (USA; Pages: 390; €95.44; ISBN: 978-1-60761-375-6Ray H. Gavin, from the Brooklyn College of The City University of New York, Brooklyn, NY, USA, wrote a few line as preface of this book. This is quite understandable: there is not a great need of words when there are facts that sustain and favour the dissemination of a cultural product. This is the case of the second edition of Cytoskeleton - Methods and Protocols, which appears just ten years after the first edition...

  13. Phage & phosphatase: a novel phage-based probe for rapid, multi-platform detection of bacteria.

    Science.gov (United States)

    Alcaine, S D; Pacitto, D; Sela, D A; Nugen, S R

    2015-11-21

    Genetic engineering of bacteriophages allows for the development of rapid, highly specific, and easily manufactured probes for the detection of bacterial pathogens. A challenge for novel probes is the ease of their adoption in real world laboratories. We have engineered the bacteriophage T7, which targets Escherichia coli, to carry the alkaline phosphatase gene, phoA. This inclusion results in phoA overexpression following phage infection of E. coli. Alkaline phosphatase is commonly used in a wide range of diagnostics, and thus a signal produced by our phage-based probe could be detected using common laboratory equipment. Our work demonstrates the successful: (i) modification of T7 phage to carry phoA; (ii) overexpression of alkaline phosphatase in E. coli; and (iii) detection of this T7-induced alkaline phosphatase activity using commercially available colorimetric and chemilumiscent methods. Furthermore, we demonstrate the application of our phage-based probe to rapidly detect low levels of bacteria and discern the antibiotic resistance of E. coli isolates. Using our bioengineered phage-based probe we were able to detect 10(3) CFU per mL of E. coli in 6 hours using a chemiluminescent substrate and 10(4) CFU per mL within 7.5 hours using a colorimetric substrate. We also show the application of this phage-based probe for antibiotic resistance testing. We were able to determine whether an E. coli isolate was resistant to ampicillin within 4.5 hours using chemiluminescent substrate and within 6 hours using a colorimetric substrate. This phage-based scheme could be readily adopted in labs without significant capital investments and can be translated to other phage-bacteria pairs for further detection.

  14. Evaluation of probe chemistries and platforms to improve the detection limit of real-time PCR

    DEFF Research Database (Denmark)

    Reynisson, E.; Josefsen, Mathilde Hartmann; Krause, Michael

    2006-01-01

    A validated PCR-based Salmonella method targeting a 94-bp sequence of the ttr gene was used as a model to compare six different combinations of reporter and quencher dyes of a TaqMan probe, on three different instruments, to improve the detection limit in a real-time PCR assay with the aim of a s...

  15. Microfluidic Technology Platforms for Synthesizing, Labeling and Measuring the Kinetics of Transport and Biochemical Reactions for Developing Molecular Imaging Probes

    Energy Technology Data Exchange (ETDEWEB)

    Phelps, Michael E.

    2009-09-01

    Radiotracer techniques are used in environmental sciences, geology, biology and medicine. Radiotracers with Positron Emission Tomography (PET) provided biological examinations of ~3 million patients 2008. Despite the success of positron labeled tracers in many sciences, there is limited access in an affordable and convenient manner to develop and use new tracers. Integrated microfluidic chips are a new technology well matched to the concentrations of tracers. Our goal is to develop microfluidic chips and new synthesis approaches to enable wide dissemination of diverse types of tracers at low cost, and to produce new generations of radiochemists for which there are many unfilled jobs. The program objectives are to: 1. Develop an integrated microfluidic platform technology for synthesizing and 18F-labeling diverse arrays of different classes of molecules. 2. Incorporate microfluidic chips into small PC controlled devices (“Synthesizer”) with a platform interfaced to PC for electronic and fluid input/out control. 3. Establish a de-centralized model with Synthesizers for discovering and producing molecular imaging probes, only requiring delivery of inexpensive [18F]fluoride ion from commercial PET radiopharmacies vs the centralized approach of cyclotron facilities synthesizing and shipping a few different types of 18F-probes. 4. Develop a position sensitive avalanche photo diode (PSAPD) camera for beta particles embedded in a microfluidic chip for imaging and measuring transport and biochemical reaction rates to valid new 18F-labeled probes in an array of cell cultures. These objectives are met within a research and educational program integrating radio-chemistry, synthetic chemistry, biochemistry, engineering and biology in the Crump Institute for Molecular Imaging. The Radiochemistry Training Program exposes PhD and post doctoral students to molecular imaging in vitro in cells and microorganisms in microfluidic chips and in vivo with PET, from new technologies

  16. Microfluidic technology platforms for synthesizing, labeling and measuring the kinetics of transport and biochemical reactions for developing molecular imaging probes

    Energy Technology Data Exchange (ETDEWEB)

    Phelps, Michael E. [Univ. of California, Los Angeles, CA (United States)

    2009-09-01

    Radiotracer techniques are used in environmental sciences, geology, biology and medicine. Radiotracers with Positron Emission Tomography (PET) provided biological examinations of ~3 million patients 2008. Despite the success of positron labeled tracers in many sciences, there is limited access in an affordable and convenient manner to develop and use new tracers. Integrated microfluidic chips are a new technology well matched to the concentrations of tracers. Our goal is to develop microfluidic chips and new synthesis approaches to enable wide dissemination of diverse types of tracers at low cost, and to produce new generations of radiochemists for which there are many unfilled jobs. The program objectives are to: 1. Develop an integrated microfluidic platform technology for synthesizing and 18F-labeling diverse arrays of different classes of molecules. 2. Incorporate microfluidic chips into small PC controlled devices (“Synthesizer”) with a platform interfaced to PC for electronic and fluid input/out control. 3. Establish a de-centralized model with Synthesizers for discovering and producing molecular imaging probes, only requiring delivery of inexpensive [18F]fluoride ion from commercial PET radiopharmacies vs the centralized approach of cyclotron facilities synthesizing and shipping a few different types of 18F-probes. 4. Develop a position sensitive avalanche photo diode (PSAPD) camera for beta particles embedded in a microfluidic chip for imaging and measuring transport and biochemical reaction rates to valid new 18F-labeled probes in an array of cell cultures. These objectives are met within a research and educational program integrating radio-chemistry, synthetic chemistry, biochemistry, engineering and biology in the Crump Institute for Molecular Imaging. The Radiochemistry Training Program exposes PhD and post doctoral students to molecular imaging in vitro in cells and microorganisms in microfluidic chips and in vivo with PET, from new technologies

  17. SERS-Activated Platforms for Immunoassay: Probes, Encoding Methods, and Applications.

    Science.gov (United States)

    Wang, Zhuyuan; Zong, Shenfei; Wu, Lei; Zhu, Dan; Cui, Yiping

    2017-06-28

    Owing to their excellent multiplexing ability, high sensitivity, and large dynamic range, immunoassays using surface-enhanced Raman scattering (SERS) as the readout signal have found prosperous applications in fields such as disease diagnosis, environmental surveillance, and food safety supervision. Various ever-increasing demands have promoted SERS-based immunoassays from the classical sandwich-type ones to those integrated with fascinating automatic platforms (e.g., test strips and microfluidic chips). As recent years have witnessed impressive progress in SERS immunoassays, we try to comprehensively cover SERS-based immunoassays from their basic working principles to specific applications. Focusing on several basic elements in SERS immunoassays, typical structures of SERS nanoprobes, productive optical spectral encoding strategies, and popular immunoassay platforms are highlighted, followed by their representative biological applications in the last 5 years. Moreover, despite the vast advances achieved to date, SERS immunoassays still suffer from some annoying shortcomings. Thus, proposals on how to improve the SERS immunoassay performance are also discussed, as well as future challenges and perspectives, aiming to give brief and valid guidelines for choosing suitable platforms according to particular applications.

  18. Probing peptide and protein insertion in a biomimetic S-layer supported lipid membrane platform.

    Science.gov (United States)

    Damiati, Samar; Schrems, Angelika; Sinner, Eva-Kathrin; Sleytr, Uwe B; Schuster, Bernhard

    2015-01-27

    The most important aspect of synthetic lipid membrane architectures is their ability to study functional membrane-active peptides and membrane proteins in an environment close to nature. Here, we report on the generation and performance of a biomimetic platform, the S-layer supported lipid membrane (SsLM), to investigate the structural and electrical characteristics of the membrane-active peptide gramicidin and the transmembrane protein α-hemolysin in real-time using a quartz crystal microbalance with dissipation monitoring in combination with electrochemical impedance spectroscopy. A shift in membrane resistance is caused by the interaction of α-hemolysin and gramicidin with SsLMs, even if only an attachment onto, or functional channels through the lipid membrane, respectively, are formed. Moreover, the obtained results did not indicate the formation of functional α-hemolysin pores, but evidence for functional incorporation of gramicidin into this biomimetic architecture is provided.

  19. A microfluidic platform for probing single cell plasma membranes using optically trapped Smart Droplet Microtools (SDMs).

    Science.gov (United States)

    Lanigan, Peter M P; Ninkovic, Tanja; Chan, Karen; de Mello, Andrew J; Willison, Keith R; Klug, David R; Templer, Richard H; Neil, Mark A A; Ces, Oscar

    2009-04-21

    We recently introduced a novel platform based upon optically trapped lipid coated oil droplets (Smart Droplet Microtools-SDMs) that were able to form membrane tethers upon fusion with the plasma membrane of single cells. Material transfer from the plasma membrane to the droplet via the tether was seen to occur. Here we present a customised version of the SDM approach based upon detergent coated droplets deployed within a microfluidic format. These droplets are able to differentially solubilise the plasma membrane of single cells with spatial selectivity and without forming membrane tethers. The microfluidic format facilitates separation of the target cells from the bulk SDM population and from downstream analysis modules. Material transfer from the cell to the SDM was monitored by tracking membrane localized EGFP.

  20. Multi-platform comparison of ten commercial master mixes for probe-based real-time polymerase chain reaction detection of bioterrorism threat agents for surge preparedness.

    Science.gov (United States)

    Buzard, Gregory S; Baker, Daniel; Wolcott, Mark J; Norwood, David A; Dauphin, Leslie A

    2012-11-30

    The Centers for Disease Control and Prevention and United States Army Research Institute for Infectious Diseases have developed real-time PCR assays for the detection of bioterrorism threat agents. These assays all rely on a limited number of approved real-time PCR master mixes. Because the availability of these reagents is a critical element of bioterrorism preparedness, we undertook a joint national preparedness exercise to address the potential surge needs resulting from a large-scale bio-emergency. We identified 9 commercially-available potential alternatives to an existing approved master mix (LightCycler FastStart DNA Master HybProbes): the TaqMan Fast Universal PCR master mix, OmniMix HS, FAST qPCR master mix, EXPRESS qPCR SuperMix kit, QuantiFast Probe PCR kit, LightCycler FastStart DNA Master(PLUS) HybProbe, Brilliant II FAST qPCR master mix, ABsolute Fast QPCR Mix and the HotStart IT Taq master mix. The performances of these kits were evaluated by the use of real-time PCR assays for four bioterrorism threat agents: Bacillus anthracis, Brucella melitensis, Burkholderia mallei and Francisella tularensis. The master mixes were compared for target-specific detection levels, as well as consistency of results among three different real-time PCR platforms (LightCycler, SmartCycler and 7500 Fast Dx). Real-time PCR analysis revealed that all ten kits performed well for agent detection on the 7500 Fast Dx instrument; however, the QuantiFast Probe PCR kit yielded the most consistently positive results across multiple real-time PCR platforms. We report that certain combinations of commonly used master mixes and instruments are not as reliable as others at detecting low concentrations of target DNA. Furthermore, our study provides laboratories the option to select from the commercial kits we evaluated to suit their preparedness needs.

  1. Platelet cytoskeleton and its hemostatic role.

    Science.gov (United States)

    Cerecedo, Doris

    2013-12-01

    Upon vascular injury, platelets adhere to the exposed extracellular matrix, which triggers the platelet activation and aggregation to form a hemostatic plug to seal the wound. All of these events involve dramatic changes in shape because of the cytoskeleton reorganization. The versatility of the cytoskeleton's main elements depends on the biochemical nature of the elements, as well as on the associated proteins that confer multiple functions within the cell. The list of these associated proteins grows actively, increasing our knowledge concerning the complexity of platelet cytoskeleton machinery. The present review evidences the recently described platelet proteins that promote characteristic modifications in their cytoskeleton organization, with special focus on the dystrophin-glycoprotein complex.

  2. Validation of pooled genotyping on the Affymetrix 500 k and SNP6.0 genotyping platforms using the polynomial-based probe-specific correction

    Directory of Open Access Journals (Sweden)

    Chew Fook Tim

    2009-12-01

    Full Text Available Abstract Background The use of pooled DNA on SNP microarrays (SNP-MaP has been shown to be a cost effective and rapid manner to perform whole-genome association evaluations. While the accuracy of SNP-MaP was extensively evaluated on the early Affymetrix 10 k and 100 k platforms, there have not been as many similarly comprehensive studies on more recent platforms. In the present study, we used the data generated from the full Affymetrix 500 k SNP set together with the polynomial-based probe-specific correction (PPC to derive allele frequency estimates. These estimates were compared to genotyping results of the same individuals on the same platform, as the basis to evaluate the reliability and accuracy of pooled genotyping on these high-throughput platforms. We subsequently extended this comparison to the new SNP6.0 platform capable of genotyping 1.8 million genetic variants. Results We showed that pooled genotyping on the 500 k platform performed as well as those previously shown on the relatively lower throughput 10 k and 100 k array sets, with high levels of accuracy (correlation coefficient: 0.988 and low median error (0.036 in allele frequency estimates. Similar results were also obtained from the SNP6.0 array set. A novel pooling strategy of overlapping sub-pools was attempted and comparison of estimated allele frequencies showed this strategy to be as reliable as replicate pools. The importance of an appropriate reference genotyping data set for the application of the PPC algorithm was also evaluated; reference samples with similar ethnic background to the pooled samples were found to improve estimation of allele frequencies. Conclusion We conclude that use of the PPC algorithm to estimate allele frequencies obtained from pooled genotyping on the high throughput 500 k and SNP6.0 platforms is highly accurate and reproducible especially when a suitable reference sample set is used to estimate the beta values for PPC.

  3. Imaging Cytoskeleton Components by Electron Microscopy

    Science.gov (United States)

    Svitkina, Tatyana

    2016-01-01

    The cytoskeleton is a complex of detergent-insoluble components of the cytoplasm playing critical roles in cell motility, shape generation, and mechanical properties of a cell. Fibrillar polymers—actin filaments, microtubules, and intermediate filaments—are major constituents of the cytoskeleton, which constantly change their organization during cellular activities. The actin cytoskeleton is especially polymorphic, as actin filaments can form multiple higher order assemblies performing different functions. Structural information about cytoskeleton organization is critical for understanding its functions and mechanisms underlying various forms of cellular activity. Because of the nanometer-scale thickness of cytoskeletal fibers, electron microscopy (EM) is a key tool to determine the structure of the cytoskeleton. This article describes application of rotary shadowing (or metal replica) EM for visualization of the cytoskeleton. The procedure is applicable to thin cultured cells growing on glass coverslips and consists of detergent extraction of cells to expose their cytoskeleton, chemical fixation to provide stability, ethanol dehydration and critical point drying to preserve three-dimensionality, rotary shadowing with platinum to create contrast, and carbon coating to stabilize replicas. This technique provides easily interpretable three-dimensional images, in which individual cytoskeletal fibers are clearly resolved, and individual proteins can be identified by immunogold labeling. More importantly, replica EM is easily compatible with live cell imaging, so that one can correlate the dynamics of a cell or its components, e.g., expressed fluorescent proteins, with high resolution structural organization of the cytoskeleton in the same cell. PMID:26498781

  4. An Eddy Current Testing Platform System for Pipe Defect Inspection Based on an Optimized Eddy Current Technique Probe Design

    Science.gov (United States)

    Rifai, Damhuji; Abdalla, Ahmed N.; Razali, Ramdan; Ali, Kharudin; Faraj, Moneer A.

    2017-01-01

    The use of the eddy current technique (ECT) for the non-destructive testing of conducting materials has become increasingly important in the past few years. The use of the non-destructive ECT plays a key role in the ensuring the safety and integrity of the large industrial structures such as oil and gas pipelines. This paper introduce a novel ECT probe design integrated with the distributed ECT inspection system (DSECT) use for crack inspection on inner ferromagnetic pipes. The system consists of an array of giant magneto-resistive (GMR) sensors, a pneumatic system, a rotating magnetic field excitation source and a host PC acting as the data analysis center. Probe design parameters, namely probe diameter, an excitation coil and the number of GMR sensors in the array sensor is optimized using numerical optimization based on the desirability approach. The main benefits of DSECT can be seen in terms of its modularity and flexibility for the use of different types of magnetic transducers/sensors, and signals of a different nature with either digital or analog outputs, making it suited for the ECT probe design using an array of GMR magnetic sensors. A real-time application of the DSECT distributed system for ECT inspection can be exploited for the inspection of 70 mm carbon steel pipe. In order to predict the axial and circumference defect detection, a mathematical model is developed based on the technique known as response surface methodology (RSM). The inspection results of a carbon steel pipe sample with artificial defects indicate that the system design is highly efficient. PMID:28335399

  5. An Eddy Current Testing Platform System for Pipe Defect Inspection Based on an Optimized Eddy Current Technique Probe Design.

    Science.gov (United States)

    Rifai, Damhuji; Abdalla, Ahmed N; Razali, Ramdan; Ali, Kharudin; Faraj, Moneer A

    2017-03-13

    The use of the eddy current technique (ECT) for the non-destructive testing of conducting materials has become increasingly important in the past few years. The use of the non-destructive ECT plays a key role in the ensuring the safety and integrity of the large industrial structures such as oil and gas pipelines. This paper introduce a novel ECT probe design integrated with the distributed ECT inspection system (DSECT) use for crack inspection on inner ferromagnetic pipes. The system consists of an array of giant magneto-resistive (GMR) sensors, a pneumatic system, a rotating magnetic field excitation source and a host PC acting as the data analysis center. Probe design parameters, namely probe diameter, an excitation coil and the number of GMR sensors in the array sensor is optimized using numerical optimization based on the desirability approach. The main benefits of DSECT can be seen in terms of its modularity and flexibility for the use of different types of magnetic transducers/sensors, and signals of a different nature with either digital or analog outputs, making it suited for the ECT probe design using an array of GMR magnetic sensors. A real-time application of the DSECT distributed system for ECT inspection can be exploited for the inspection of 70 mm carbon steel pipe. In order to predict the axial and circumference defect detection, a mathematical model is developed based on the technique known as response surface methodology (RSM). The inspection results of a carbon steel pipe sample with artificial defects indicate that the system design is highly efficient.

  6. An Eddy Current Testing Platform System for Pipe Defect Inspection Based on an Optimized Eddy Current Technique Probe Design

    Directory of Open Access Journals (Sweden)

    Damhuji Rifai

    2017-03-01

    Full Text Available The use of the eddy current technique (ECT for the non-destructive testing of conducting materials has become increasingly important in the past few years. The use of the non-destructive ECT plays a key role in the ensuring the safety and integrity of the large industrial structures such as oil and gas pipelines. This paper introduce a novel ECT probe design integrated with the distributed ECT inspection system (DSECT use for crack inspection on inner ferromagnetic pipes. The system consists of an array of giant magneto-resistive (GMR sensors, a pneumatic system, a rotating magnetic field excitation source and a host PC acting as the data analysis center. Probe design parameters, namely probe diameter, an excitation coil and the number of GMR sensors in the array sensor is optimized using numerical optimization based on the desirability approach. The main benefits of DSECT can be seen in terms of its modularity and flexibility for the use of different types of magnetic transducers/sensors, and signals of a different nature with either digital or analog outputs, making it suited for the ECT probe design using an array of GMR magnetic sensors. A real-time application of the DSECT distributed system for ECT inspection can be exploited for the inspection of 70 mm carbon steel pipe. In order to predict the axial and circumference defect detection, a mathematical model is developed based on the technique known as response surface methodology (RSM. The inspection results of a carbon steel pipe sample with artificial defects indicate that the system design is highly efficient.

  7. The Cytoskeleton in Papillomavirus Infection

    Directory of Open Access Journals (Sweden)

    Malgorzata Bienkowska-Haba

    2011-03-01

    Full Text Available Cytoskeleton defines the shape and structural organization of the cell. Its elements participate in cell motility, intracellular transport and chromosome movement during mitosis. Papillomaviruses (PV are strictly epitheliotropic and induce self-limiting benign tumors of skin and mucosa, which may progress to malignancy. Like many other viruses, PV use the host cytoskeletal components for several steps during their life cycle. Prior to internalization, PV particles are transported along filopodia to the cell body. Following internalization, retrograde transport along microtubules via the dynein motor protein complex is observed. In addition, viral minichromosomes depend on the host cell machinery for partitioning of viral genomes during mitosis, which may be affected by oncoproteins E6 and E7 of high-risk human PV types. This mini-review summarizes recent advances in our understanding of papillomavirus’ interactions with the host cell cytoskeletal elements.

  8. Transcript profiling of two alfalfa genotypes with contrasting cell wall composition in stems using a cross-species platform: optimizing analysis by masking biased probes

    Science.gov (United States)

    2010-01-01

    Background The GeneChip® Medicago Genome Array, developed for Medicago truncatula, is a suitable platform for transcript profiling in tetraploid alfalfa [Medicago sativa (L.) subsp. sativa]. However, previous research involving cross-species hybridization (CSH) has shown that sequence variation between two species can bias transcript profiling by decreasing sensitivity (number of expressed genes detected) and the accuracy of measuring fold-differences in gene expression. Results Transcript profiling using the Medicago GeneChip® was conducted with elongating stem (ES) and post-elongation stem (PES) internodes from alfalfa genotypes 252 and 1283 that differ in stem cell wall concentrations of cellulose and lignin. A protocol was developed that masked probes targeting inter-species variable (ISV) regions of alfalfa transcripts. A probe signal intensity threshold was selected that optimized both sensitivity and accuracy. After masking for both ISV regions and previously identified single-feature polymorphisms (SFPs), the number of differentially expressed genes between the two genotypes in both ES and PES internodes was approximately 2-fold greater than the number detected prior to masking. Regulatory genes, including transcription factor and receptor kinase genes that may play a role in development of secondary xylem, were significantly over-represented among genes up-regulated in 252 PES internodes compared to 1283 PES internodes. Several cell wall-related genes were also up-regulated in genotype 252 PES internodes. Real-time quantitative RT-PCR of differentially expressed regulatory and cell wall-related genes demonstrated increased sensitivity and accuracy after masking for both ISV regions and SFPs. Over 1,000 genes that were differentially expressed in ES and PES internodes of genotypes 252 and 1283 were mapped onto putative orthologous loci on M. truncatula chromosomes. Clustering simulation analysis of the differentially expressed genes suggested co

  9. Transcript profiling of two alfalfa genotypes with contrasting cell wall composition in stems using a cross-species platform: optimizing analysis by masking biased probes

    Directory of Open Access Journals (Sweden)

    Jung Hans-Joachim G

    2010-05-01

    Full Text Available Abstract Background The GeneChip® Medicago Genome Array, developed for Medicago truncatula, is a suitable platform for transcript profiling in tetraploid alfalfa [Medicago sativa (L. subsp. sativa]. However, previous research involving cross-species hybridization (CSH has shown that sequence variation between two species can bias transcript profiling by decreasing sensitivity (number of expressed genes detected and the accuracy of measuring fold-differences in gene expression. Results Transcript profiling using the Medicago GeneChip® was conducted with elongating stem (ES and post-elongation stem (PES internodes from alfalfa genotypes 252 and 1283 that differ in stem cell wall concentrations of cellulose and lignin. A protocol was developed that masked probes targeting inter-species variable (ISV regions of alfalfa transcripts. A probe signal intensity threshold was selected that optimized both sensitivity and accuracy. After masking for both ISV regions and previously identified single-feature polymorphisms (SFPs, the number of differentially expressed genes between the two genotypes in both ES and PES internodes was approximately 2-fold greater than the number detected prior to masking. Regulatory genes, including transcription factor and receptor kinase genes that may play a role in development of secondary xylem, were significantly over-represented among genes up-regulated in 252 PES internodes compared to 1283 PES internodes. Several cell wall-related genes were also up-regulated in genotype 252 PES internodes. Real-time quantitative RT-PCR of differentially expressed regulatory and cell wall-related genes demonstrated increased sensitivity and accuracy after masking for both ISV regions and SFPs. Over 1,000 genes that were differentially expressed in ES and PES internodes of genotypes 252 and 1283 were mapped onto putative orthologous loci on M. truncatula chromosomes. Clustering simulation analysis of the differentially expressed genes

  10. Chaperonin filaments: The archael cytoskeleton

    Energy Technology Data Exchange (ETDEWEB)

    Trent, J.D.; Kagawa, H.K.; Yaoi, Takuro; Olle, E.; Zaluzec, N.J.

    1997-08-01

    Chaperonins are multi-subunit double-ring complexed composed of 60-kDa proteins that are believed to mediate protein folding in vivo. The chaperonins in the hyperthermophilic archaeon Sulfolobus shibatae are composed of the organism`s two most abundant proteins, which represent 4% of its total protein and have an intracellular concentration of {ge} 3.0 mg/ml. At concentrations of 1.0 mg/ml, purified chaperonin proteins aggregate to form ordered filaments. Filament formation, which requires Mg{sup ++} and nucleotide binding (not hydrolysis), occurs at physiological temperatures under conditions suggesting filaments may exist in vivo. If the estimated 4,600 chaperonins per cell, formed filaments in vivo, they could create a matrix of filaments that would span the diameter of an average S. shibatae cell 100 times. Direct observations of unfixed, minimally treated cells by intermediate voltage electron microscopy (300 kV) revealed an intracellular network of filaments that resembles chaperonin filaments produced in vitro. The hypothesis that the intracellular network contains chaperonins is supported by immunogold analyses. The authors propose that chaperonin activity may be regulated in vivo by filament formation and that chaperonin filaments may serve a cytoskeleton-like function in archaea and perhaps in other prokaryotes.

  11. Solid-state probe based electrochemical aptasensor for cocaine: a potentially convenient, sensitive, repeatable, and integrated sensing platform for drugs.

    Science.gov (United States)

    Du, Yan; Chen, Chaogui; Yin, Jianyuan; Li, Bingling; Zhou, Ming; Dong, Shaojun; Wang, Erkang

    2010-02-15

    Aptamers, which are artificial oligonucleotides selected in vitro, have been employed to design novel biosensors (i.e., aptasensors). In this work, we first constructed a label-free electrochemical aptasensor introducing a probe immobilization technique by the use of a layer-by-layer (LBL) self-assembled multilayer with ferrocene-appended poly(ethyleneimine) (Fc-PEI) on an indium tin oxide (ITO) array electrode for detection of cocaine. The Fc-PEI and gold nanoparticles (AuNPs) were LBL assembled on the electrode surface via electrostatic interaction. Then, cocaine aptamer fragments, SH-C2, were covalently labeled onto the outermost AuNP layer. When the target cocaine and cocaine aptamer C1 were present simultaneously, the SH-C2 layer hybridized partly with C1 to bind the cocaine, which led to a decreased differential pulse voltammetry (DPV) signal of Fc-PEI. This DPV signal change could be used to sensitively detect cocaine with the lowest detectable concentration down to 0.1 microM and the detection range up to 38.8 microM, which falls in the the expected range for medical use of detecting drug abuse involving cocaine. Meanwhile, the sensor was specific to cocaine in complex biologic fluids such as human plasma, human saliva, etc. The sensing strategy had general applicability, and the detection of thrombin could also be realized, displayed a low detection limit, and exhibited worthiness to other analytes. The aptasensor based on the array electrode held promising potential for integration of the sensing ability in multianalysis for simultaneous detection.

  12. Fluorescent taxoids as probes of the microtubule cytoskeleton.

    Science.gov (United States)

    Evangelio, J A; Abal, M; Barasoain, I; Souto, A A; Lillo, M P; Acuña, A U; Amat-Guerri, F; Andreu, J M

    1998-01-01

    Microtubules are specifically and efficiently visualized with the new fluorescent taxoids 7-O-[N-(4'-fluoresceincarbonyl)-L-alanyl]taxol (FLUTAX) and 7-O-[N-(4'-tetramethylrhodaminecarbonyl)-L-alanyl]taxol (ROTAX). Similarly to taxol, FLUTAX and ROTAX are able to drive inactive GDP-liganded tubulin into microtubule assembly. One molecule of FLUTAX binds per alphabeta-tubulin dimer assembled, competing with taxol for the same microtubule binding site with an eightfold smaller relative affinity. FLUTAX-induced microtubule elongation is markedly Mg2+-dependent, encompassing the binding of one Mg2+ ion more per tubulin dimer polymerized than in the case of taxol. A small perturbation of the absorption spectrum of bound FLUTAX is consistent with a cationic microenvironment relative to the solution. The fluorescence anisotropy of FLUTAX increases by an order of magnitude upon binding to microtubules and time-resolved measurements indicate that the fluorescein moiety remains considerably mobile on a protein surface. The rate of labeling suggests that this is the outer microtubule wall. Alternatively, the microtubule lumen would be functional. FLUTAX- and ROTAX-induced microtubules, radial structures, and organized microtubule bundles are readily observed under the fluorescence microscope. Rapid and accurate visualization of native (or very mildly fixed) cytoplasmic and spindle microtubules of a variety of permeabilized cells is simply obtained with micromolar FLUTAX, with an advantage over immunofluorescence. In addition, FLUTAX labels the centrosomes of PtK2 cells more intensely than antibodies to alpha- or beta-tubulin, and co-localizing with antibodies to gamma-tubulin. Two brightly fluorescent spots, probably separating or duplicating centrioles, can be resolved in the centrosomes of interphase cells. This finding indicates that centrosomes may well be additional targets of action of taxoids. FLUTAX strongly labels microtubules near the spindle poles, as well as microtubules at the telophase spindle equator and the central part of the midbody in cytokinesis (instead of the dark zone frequently observed with immunofluorescence), suggesting a predominant interaction of FLUTAX with sites at which tubulin is newly polymerized. Nanomolar concentrations of FLUTAX also permit specific imaging of centrosomes, half-spindles and midbodies in growing U937 cells.

  13. Nanosecond pulsed electric field induced cytoskeleton, nuclear membrane and telomere damage adversely impact cell survival.

    Science.gov (United States)

    Stacey, M; Fox, P; Buescher, S; Kolb, J

    2011-10-01

    We investigated the effects of nanosecond pulsed electric fields (nsPEF) on three human cell lines and demonstrated cell shrinkage, breakdown of the cytoskeleton, nuclear membrane and chromosomal telomere damage. There was a differential response between cell types coinciding with cell survival. Jurkat cells showed cytoskeleton, nuclear membrane and telomere damage that severely impacted cell survival compared to two adherent cell lines. Interestingly, disruption of the actin cytoskeleton in adherent cells prior to nsPEF exposure significantly reduced cell survival. We conclude that nsPEF applications are able to induce damage to the cytoskeleton and nuclear membrane. Telomere sequences, regions that tether and stabilize DNA to the nuclear membrane, are severely compromised as measured by a pan-telomere probe. Internal pore formation following nsPEF applications has been described as a factor in induced cell death. Here we suggest that nsPEF induced physical changes to the cell in addition to pore formation need to be considered as an alternative method of cell death. We suggest nsPEF electrochemical induced depolymerization of actin filaments may account for cytoskeleton and nuclear membrane anomalies leading to sensitization.

  14. Thermally Controlling the Polymeric Cytoskeleton in Living Cells

    Science.gov (United States)

    Cheng, Chao-Min; Leduc, Philip

    2006-03-01

    Cell structure is controlled to a large degree by the cytoskeleton, which is an intracellular polymer network. This cytoskeleton is critical as it strongly influences many cellular functions such as motility, organelle transport, mechanotransduction and mitosis. In our studies, we controlled the thermal environment of living cells and after applying an increase in temperature of only 5 ^oC, we observed a change in the polymer network as the actin filaments depolymerized. Interestingly, when we then lowered the temperature, the actin repolymerized indicating a reversible phase that is controlled by the thermal environment. We characterized the presence of F-actin and G-actin for these phases through analyzing the intensity from immunofluorescent studies for these proteins. The F-actin concentration decreased when increasing the temperature from the initial state and then increased when decreasing the temperature. Although the cell is known to be affected by heat shock responses, this is not a function of just the polymers as they do not exhibit these polymerization characteristics when we probed them as single filaments in vitro. These studies suggest that the cell has distinct phases or patterns while maintaining a reversible equilibrium due to the thermal environment for these networked polymers.

  15. Coupling of cytoskeleton functions for fibroblast locomotion

    DEFF Research Database (Denmark)

    Couchman, J R; Lenn, M; Rees, D A

    1985-01-01

    caused visible protrusions in projected positions at the leading edge. We conclude that fibroblast locomotion may be driven coordinately by a common set of motility mechanisms and that this coordination may be lost as a result of physical or pharmacological disturbance. Taking our evidence with results...... from other Laboratories, we propose the following cytoskeleton functions. (i) Protrusive activity, probably based on solation--gelation cycles of the actin based cytoskeleton and membrane recycling which provides cellular and membrane components for streaming through the cell body to the leading edge...

  16. Sensor potency of the moonlighting enzyme-decorated cytoskeleton: the cytoskeleton as a metabolic sensor

    Directory of Open Access Journals (Sweden)

    Norris Vic

    2013-02-01

    Full Text Available Abstract Background There is extensive evidence for the interaction of metabolic enzymes with the eukaryotic cytoskeleton. The significance of these interactions is far from clear. Presentation of the hypothesis In the cytoskeletal integrative sensor hypothesis presented here, the cytoskeleton senses and integrates the general metabolic activity of the cell. This activity depends on the binding to the cytoskeleton of enzymes and, depending on the nature of the enzyme, this binding may occur if the enzyme is either active or inactive but not both. This enzyme-binding is further proposed to stabilize microtubules and microfilaments and to alter rates of GTP and ATP hydrolysis and their levels. Testing the hypothesis Evidence consistent with the cytoskeletal integrative sensor hypothesis is presented in the case of glycolysis. Several testable predictions are made. There should be a relationship between post-translational modifications of tubulin and of actin and their interaction with metabolic enzymes. Different conditions of cytoskeletal dynamics and enzyme-cytoskeleton binding should reveal significant differences in local and perhaps global levels and ratios of ATP and GTP. The different functions of moonlighting enzymes should depend on cytoskeletal binding. Implications of the hypothesis The physical and chemical effects arising from metabolic sensing by the cytoskeleton would have major consequences on cell shape, dynamics and cell cycle progression. The hypothesis provides a framework that helps the significance of the enzyme-decorated cytoskeleton be determined.

  17. Dynamic organization of actin cytoskeleton during the polarity formation and germination of pollen protoplasts

    Institute of Scientific and Technical Information of China (English)

    XU Xia; Zl Huijun; SUN Yina; REN Haiyun

    2004-01-01

    The formation of the polarity of pollen protoplast and the dynamics of actin cytoskeleton were observed by non-fixation, Alexa-Phalloidin probing and confocal laser scanning microscopy. Our results showed that the protoplast obtained from stored pollen contained numerous crystalline fusiform bodies to constitute a storage form of actin. When dormant pollen was hydrated, the actin cytoskeleton forms a fine network spreading uniformly in the protoplast. In the process of polarity formation and germination of pollen protoplast, actin filaments marshaled slowly to the brim, and then formed multilayer continuous actin filament bundles surrounding the cortical of the protoplast. When the protoplast was exposed to actin filament-disrupting drugs, such as Latrunculin A and Cytochalasin D, continuously arranged actin bundles were disturbed and in this condition, the protoplast could not germinate. But when exposed to actin filament stabiling drug-phalliodin, the dynamics of actin filaments in the protoplasts behaved normally and the protoplasts could germinate normally. These results were also confirmed by the pharmacology experiments on pollen grains. And when Latrunculin A or Cytochalasin D was washed off, the ratio of pollen germination was resumed partly. All the results above show that the dynamic organization of the actin cytoskeleton are critical in the cell polarity formation and germination of pollen protoplast, and that the reorganization of actin cytoskeleton is mainly due to the rearrangement of actin filament arrays.

  18. Subcortical cytoskeleton periodicity throughout the nervous system.

    Science.gov (United States)

    D'Este, Elisa; Kamin, Dirk; Velte, Caroline; Göttfert, Fabian; Simons, Mikael; Hell, Stefan W

    2016-03-07

    Superresolution fluorescence microscopy recently revealed a ~190 nm periodic cytoskeleton lattice consisting of actin, spectrin, and other proteins underneath the membrane of cultured hippocampal neurons. Whether the periodic cytoskeleton lattice is a structural feature of all neurons and how it is modified when axons are ensheathed by myelin forming glial cells is not known. Here, STED nanoscopy is used to demonstrate that this structure is a commonplace of virtually all neuron types in vitro. To check how the subcortical meshwork is modified during myelination, we studied sciatic nerve fibers from adult mice. Periodicity of both actin and spectrin was uncovered at the internodes, indicating no substantial differences between unmyelinated and myelinated axons. Remarkably, the actin/spectrin pattern was also detected in glial cells such as cultured oligodendrocyte precursor cells. Altogether our work shows that the periodic subcortical cytoskeletal meshwork is a fundamental characteristic of cells in the nervous system and is not a distinctive feature of neurons, as previously thought.

  19. Cytoskeleton and Early Development in Fucoid Algae

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Cell polarization and asymmetric cell divisions play important roles during development in many multicellular eukaryotes.Fucoid algae have a long history as models for studying early developmental processes, probably because of the ease with which zygotes can be observed and manipulated in the laboratory. This review discusses cell polarization and asymmetric cell divisions in fucoid algal zygotes with an emphasis on the roles played by the cytoskeleton.

  20. Subproteome analysis of the neutrophil cytoskeleton

    OpenAIRE

    Xu, Ping; Crawford, Mark; Way, Michael; Godovac-Zimmermann, Jasminka; Segal, Anthony W.; Radulovic, Marko

    2009-01-01

    Neutrophils play a key role in the early host-defense mechanisms due to their capacity to migrate into inflamed tissues and phagocytose microorganisms. The cytoskeleton has an essential role in these neutrophil functions, however, its composition is still poorly understood. We separately analyzed different cytoskeletal compartments: cytosolic skeleton, phagosome membrane skeleton, and plasma membrane skeleton. Using a proteomic approach, 138 nonredundant proteins were identified. Proteins not...

  1. On the cytoskeleton and soft glassy rheology.

    Science.gov (United States)

    Mandadapu, Kranthi K; Govindjee, Sanjay; Mofrad, Mohammad R K

    2008-01-01

    The cytoskeleton is a complex structure within the cellular corpus that is responsible for the main structural properties and motilities of cells. A wide range of models have been utilized to understand cytoskeletal rheology and mechanics (see e.g. [Mofrad, M., Kamm, R., 2006. Cytoskeletal Mechanics: Models and Measurements. Cambridge University Press, Cambridge]). From this large collection of proposed models, the soft glassy rheological model (originally developed for inert soft glassy materials) has gained a certain traction in the literature due to the close resemblance of its predictions to certain mechanical data measured on cell cultures [Fabry, B., Maksym, G., Butler, J., Glogauer, M., Navajas, D., Fredberg, J., 2001. Scaling the microrheology of living cells. Physical Review Letters 87, 14102]. We first review classical linear rheological theory in a concise fashion followed by an examination of the soft glassy rheological theory. With this background we discuss the observed behavior of the cytoskeleton and the inherent limitations of classical rheological models for the cytoskeleton. This then leads into a discussion of the advantages and disadvantages presented to us by the soft glassy rheological model. We close with some comments of caution and recommendations on future avenues of exploration.

  2. Neuronal cytoskeleton in synaptic plasticity and regeneration.

    Science.gov (United States)

    Gordon-Weeks, Phillip R; Fournier, Alyson E

    2014-04-01

    During development, dynamic changes in the axonal growth cone and dendrite are necessary for exploratory movements underlying initial axo-dendritic contact and ultimately the formation of a functional synapse. In the adult central nervous system, an impressive degree of plasticity is retained through morphological and molecular rearrangements in the pre- and post-synaptic compartments that underlie the strengthening or weakening of synaptic pathways. Plasticity is regulated by the interplay of permissive and inhibitory extracellular cues, which signal through receptors at the synapse to regulate the closure of critical periods of developmental plasticity as well as by acute changes in plasticity in response to experience and activity in the adult. The molecular underpinnings of synaptic plasticity are actively studied and it is clear that the cytoskeleton is a key substrate for many cues that affect plasticity. Many of the cues that restrict synaptic plasticity exhibit residual activity in the injured adult CNS and restrict regenerative growth by targeting the cytoskeleton. Here, we review some of the latest insights into how cytoskeletal remodeling affects neuronal plasticity and discuss how the cytoskeleton is being targeted in an effort to promote plasticity and repair following traumatic injury in the central nervous system. © 2013 International Society for Neurochemistry.

  3. A surface enhanced Raman scattering quantitative analytical platform for detection of trace Cu coupled the catalytic reaction and gold nanoparticle aggregation with label-free Victoria blue B molecular probe.

    Science.gov (United States)

    Li, Chongning; Ouyang, Huixiang; Tang, Xueping; Wen, Guiqing; Liang, Aihui; Jiang, Zhiliang

    2017-01-15

    With development of economy and society, there is an urgent need to develop convenient and sensitive methods for detection of Cu(2+) pollution in water. In this article, a simple and sensitive SERS sensor was proposed to quantitative analysis of trace Cu(2+) in water. The SERS sensor platform was prepared a common gold nanoparticle (AuNP)-SiO2 sol substrate platform by adsorbing HSA, coupling with the catalytic reaction of Cu(2+)-ascorbic acid (H2A)-dissolved oxygen, and using label-free Victoria blue B (VBB) as SERS molecular probes. The SERS sensor platform response to the AuNP aggregations by hydroxyl radicals (•OH) oxidizing from the Cu(2+) catalytic reaction, which caused the SERS signal enhancement. Therefore, by monitoring the increase of SERS signal, Cu(2+) in water can be determined accurately. The results show that the SERS sensor platforms owns a linear response with a range from 0.025 to 25μmol/L Cu(2+), and with a detection limit of 0.008μmol/L. In addition, the SERS method demonstrated good specificity for Cu(2+), which can determined accurately trace Cu(2+) in water samples, and good recovery and accuracy are obtained for the water samples. With its high selectivity and good accuracy, the sensitive SERS quantitative analysis method is expected to be a promising candidate for determining copper ions in environmental monitoring and food safety.

  4. Adaptive rheology and ordering of cell cytoskeleton govern matrix rigidity sensing

    Science.gov (United States)

    Gupta, Mukund; Sarangi, Bibhu Ranjan; Deschamps, Joran; Nematbakhsh, Yasaman; Callan-Jones, Andrew; Margadant, Felix; Mège, René-Marc; Lim, Chwee Teck; Voituriez, Raphaël; Ladoux, Benoît

    2015-01-01

    Matrix rigidity sensing regulates a large variety of cellular processes and has important implications for tissue development and disease. However, how cells probe matrix rigidity, and hence respond to it, remains unclear. Here, we show that rigidity sensing and adaptation emerge naturally from actin cytoskeleton remodeling. Our in vitro experiments and theoretical modeling demonstrate a bi-phasic rheology of the actin cytoskeleton, which transitions from fluid on soft substrates to solid on stiffer ones. Furthermore, we find that increasing substrate stiffness correlates with the emergence of an orientational order in actin stress fibers, which exhibit an isotropic to nematic transition that we characterize quantitatively in the framework of active matter theory. These findings imply mechanisms mediated by a large-scale reinforcement of actin structures under stress, which could be the mechanical drivers of substrate stiffness dependent cell shape changes and cell polarity. PMID:26109233

  5. Cytoskeleton Molecular Motors: Structures and Their Functions in Neuron.

    Science.gov (United States)

    Xiao, Qingpin; Hu, Xiaohui; Wei, Zhiyi; Tam, Kin Yip

    2016-01-01

    Cells make use of molecular motors to transport small molecules, macromolecules and cellular organelles to target region to execute biological functions, which is utmost important for polarized cells, such as neurons. In particular, cytoskeleton motors play fundamental roles in neuron polarization, extension, shape and neurotransmission. Cytoskeleton motors comprise of myosin, kinesin and cytoplasmic dynein. F-actin filaments act as myosin track, while kinesin and cytoplasmic dynein move on microtubules. Cytoskeleton motors work together to build a highly polarized and regulated system in neuronal cells via different molecular mechanisms and functional regulations. This review discusses the structures and working mechanisms of the cytoskeleton motors in neurons.

  6. The desmosomal plaque and the cytoskeleton.

    Science.gov (United States)

    Franke, W W; Cowin, P; Schmelz, M; Kapprell, H P

    1987-01-01

    Two major plasma membrane domains are involved in the architectural organization of the cytoskeleton. Both are junctions of the adherens category characterized by the presence of dense plaques associated with the cytoplasmic surface of their membranes. The plaques serve as specific anchorage structures for two different types of cytoplasmic filaments. Intermediate-sized filaments (IF) of several types, i.e. cytokeratin IF in epithelial cells, desmin IF in cardiac myocytes and vimentin IF in arachnoidal cells of meninges, meningiomas and several other cells, attach to the desmosomal plaques, whereas actin-containing microfilaments associate with non-desmosomal adhering junctions such as the zonula adherens, fascia adherens and punctum adherens. The plaques of both kinds of adhering junctions contain a common acidic polypeptide of Mr 83,000 identical to 'band 5 protein' of bovine snout epidermal desmosomes. However, other plaque components are mutually exclusive to one of the two subclasses of adhering junctions. The desmosomal plaque structure, which does not contain vinculin and alpha-actinin, comprises representatives of cytoplasmic, non-membrane-integrated proteins such as desmoplakin(s) and the cytoplasmic portions of transmembrane glycoproteins such as 'band 3 glycoprotein'. The analysis of both categories of junction-associated plaques should provide a basis for understanding the establishment and the dynamics of junction-cytoskeleton interaction.

  7. Fluorescence Imaging of the Cytoskeleton in Plant Roots.

    Science.gov (United States)

    Dyachok, Julia; Paez-Garcia, Ana; Yoo, Cheol-Min; Palanichelvam, Karuppaiah; Blancaflor, Elison B

    2016-01-01

    During the past two decades the use of live cytoskeletal probes has increased dramatically due to the introduction of the green fluorescent protein. However, to make full use of these live cell reporters it is necessary to implement simple methods to maintain plant specimens in optimal growing conditions during imaging. To image the cytoskeleton in living Arabidopsis roots, we rely on a system involving coverslips coated with nutrient supplemented agar where the seeds are directly germinated. This coverslip system can be conveniently transferred to the stage of a confocal microscope with minimal disturbance to the growth of the seedling. For roots with a larger diameter such as Medicago truncatula, seeds are first germinated in moist paper, grown vertically in between plastic trays, and roots mounted on glass slides for confocal imaging. Parallel with our live cell imaging approaches, we routinely process fixed plant material via indirect immunofluorescence. For these methods we typically use non-embedded vibratome-sectioned and whole mount permeabilized root tissue. The clearly defined developmental regions of the root provide us with an elegant system to further understand the cytoskeletal basis of plant development.

  8. Spatial constraints and the organization of the cytoskeleton

    NARCIS (Netherlands)

    Ga^rlea, I.C.

    2015-01-01

    The shape of animal cells is in controlled by a network of filamentous polymers called the cytoskeleton. The two main components of the cytoskeleton are actin filaments and microtubules. These polymers continuously reorganize in order to performed their diverse cellular functions. For example, in pr

  9. Spatial organisation of cell expansion by the cytoskeleton

    NARCIS (Netherlands)

    Ketelaar, T.

    2002-01-01

    The shape of plants is determined by the sum of cell division and cell growth. The cytoskeleton plays an important role in both processes. This thesis presents research that pinpoints how the cytoskeleton controls plant cell growth. Root hairs of the model plant Arabidopsis have been used as a model

  10. VISUALIZATION OF DYNAMIC ORGANIZATION OF CYTOSKELETON GELS IN LIVING CELLS BY HYBRID—SPM

    Institute of Scientific and Technical Information of China (English)

    K.Kawabata; Y.Sado; M.Nagayama; T.Nitta; K.Nemoto; Y.Koyama; H.Haga

    2003-01-01

    We succeeded in performing of hybrid Scanning Probe Microscopy(hybrid-SPM) in which mechanical-SPM and fluorescence microscopy are combined.This technique is able to measure simultaneously mechanical properties and distribution of cytoskeletons of lining cells by using green fluorescent protein.We measured evolution of both local elasticity and distributions of actin stress fibers in an identical fibroblast living in physiological conditions.The SPM experiments revealed that stiffer lines develop in living cells,which correspond to actin stress fibers.The elasticity of the actin stress fibers is as high as 100kPa.We discuss mechanical effects on the development of actin filament networks.

  11. VISUALIZATION OF DYNAMIC ORGANIZATION OF CYTOSKELETON GELS IN LIVING CELLS BY HYBRID-SPM

    Institute of Scientific and Technical Information of China (English)

    K.Kawabata; Y.Sado; M.Nagayama; T.Nitta; K.Nemoto; Y.Koyama; H.Haga

    2003-01-01

    We succeeded in performing of hybrid Scanning Probe Microscopy (hybrid-SPM) in which mechanical-SPM and fluorescence microscopy are combined. This technique is able to measure simultaneously mechanical properties and distribution of cytoskeletons of living cells by using green fluorescent protein. We measured evolution of both local elasticity and distributions of actin stress fibers in an identical fibroblast living in physiological conditions. The SPM experiments revealed that stiffer lines develop in living cells, which correspond to actin stress fibers. The elasticity of the actin stress fibers is as high as 100 kPa. We discuss mechanical effects on the development of actin filament networks.

  12. Intracellular cytoskeletal elements and cytoskeletons in bacteria.

    Science.gov (United States)

    Madkour, Mohamed H F; Mayer, Frank

    2007-01-01

    Within a short period of time after the discovery of bacterial cytoskletons, major progress had been made in areas such as general spatial layout of cytoskeletons, their involvement in a variety of cellfunctions (shape control, cell division, chromosome segregation, cell motility). This progress was achieved by application of advanced investigation techniques. Homologs of eukaryotic actin, tubulin, and intermediate filaments were found in bacteria; cytoskeletal proteins not closely or not at all related to any of these major cytoskeletal proteins were discovered in a number of bacteria such as Mycoplasmas, Spiroplasmas, Spirochetes, Treponema, Caulobacter. A structural role for bacterial elongation factor Tu was indicated. On the basis of this new thinking, new approaches in biotechnology and new drugs are on the way.

  13. Cytoskeleton as an Emerging Target of Anthrax Toxins

    Directory of Open Access Journals (Sweden)

    Jean-Nicolas Tournier

    2012-02-01

    Full Text Available Bacillus anthracis, the agent of anthrax, has gained virulence through its exotoxins produced by vegetative bacilli and is composed of three components forming lethal toxin (LT and edema toxin (ET. So far, little is known about the effects of these toxins on the eukaryotic cytoskeleton. Here, we provide an overview on the general effects of toxin upon the cytoskeleton architecture. Thus, we shall discuss how anthrax toxins interact with their receptors and may disrupt the interface between extracellular matrix and the cytoskeleton. We then analyze what toxin molecular effects on cytoskeleton have been described, before discussing how the cytoskeleton may help the pathogen to corrupt general cell processes such as phagocytosis or vascular integrity.

  14. 泗水县气象灾害预警平台建设探析%Probe into the Construction of Meteorological Disaster Warning Platform in Sishui County

    Institute of Scientific and Technical Information of China (English)

    王新友; 董宁

    2012-01-01

    The construction, application, configuring the technical requirements and layout principle of monitoring system station network of meteorological disaster warning platform in Sishui County were described. Using the Internet network, GIS geographic information, cellular network bandwith, embedded text-to-speech conversion, LED display control technology, according to the technical requirements of flash geological disaster early warning platform configuration and layout principle of monitoring system station network, the disaster early warning platform with wireless text turn language emergency broadcasting, telephone emergency broadcast and wireless LED display was built in Sishui County to achieve the butt joint between meteorological disaster early warning platform and the basic information acquisition system of related departments, and establish basic information database of social economy and natural geography, meteorological disaster risk database and flash flood disaster index database to realize resources sharing which become the stable and reliable warning means of timely monitoring, early warning and forecast and all kinds of disaster warning information dissemination to flash flood disaster.%介绍了泗水县气象灾害预警平台的建设与应用情况、配置技术要求以及监测系统站网布设的原则。利用Internet网络、GIS地理信息、蜂窝网络带宽传输、嵌入式文语转换、LED显示控制等技术,按照山洪地质灾害预警平台配置技术要求以及监测系统站网布设原则,建设成了泗水县集无线文转语应急广播、电话应急广播、无线LED显示屏发布于一体的灾害预警平台,实现了各级气象灾害预警平台与相关部门的基础信息采集系统对接,建立社会经济和自然地理基础资料数据库、气象灾害风险数据库、山洪地质灾害指标库等资源的共享,已成为山洪灾害的及时监测、预警预报以及各类灾害预警信

  15. Yeast studies reveal moonlighting functions of the ancient actin cytoskeleton

    Science.gov (United States)

    Sattlegger, Evelyn; Chernova, Tatiana A.; Gogoi, Neeku M.; Pillai, Indu V.; Chernoff, Yury O.; Munn, Alan L.

    2014-01-01

    Classic functions of the actin cytoskeleton include control of cell size and shape and the internal organisation of cells. These functions are manifest in cellular processes of fundamental importance throughout biology such as the generation of cell polarity, cell migration, cell adhesion and cell division. However, studies in the unicellular model eukaryote Saccharomyces cerevisiae (Baker's yeast) are giving insights into other functions in which the actin cytoskeleton plays a critical role. These include endocytosis, control of protein translation and determination of protein 3-dimensional shape (especially conversion of normal cellular proteins into prions). Here we present a concise overview of these new "moonlighting" roles for the actin cytoskeleton and how some of these roles might lie at the heart of important molecular switches. This is an exciting time for researchers interested in the actin cytoskeleton. We show here how studies of actin are leading us into many new and exciting realms at the interface of genetics, biochemistry and cell biology. While many of the pioneering studies have been conducted using yeast, the conservation of the actin cytoskeleton and its component proteins throughout eukaryotes suggests that these new roles for the actin cytoskeleton may not be restricted to yeast cells but rather may reflect new roles for the actin cytoskeleton of all eukaryotes. PMID:25138357

  16. Comparison of DC and AC Transport in 1.5-7.5 nm Oligophenylene Imine Molecular Wires across Two Junction Platforms: Eutectic Ga-In versus Conducting Probe Atomic Force Microscope Junctions.

    Science.gov (United States)

    Sangeeth, C S Suchand; Demissie, Abel T; Yuan, Li; Wang, Tao; Frisbie, C Daniel; Nijhuis, Christian A

    2016-06-15

    We have utilized DC and AC transport measurements to measure the resistance and capacitance of thin films of conjugated oligophenyleneimine (OPI) molecules ranging from 1.5 to 7.5 nm in length. These films were synthesized on Au surfaces utilizing the imine condensation chemistry between terephthalaldehyde and 1,4-benzenediamine. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy yielded molecular tilt angles of 33-43°. To probe DC and AC transport, we employed Au-S-OPI//GaOx/EGaIn junctions having contact areas of 9.6 × 10(2) μm(2) (10(9) nm(2)) and compared to previously reported DC results on the same OPI system obtained using Au-S-OPI//Au conducting probe atomic force microscopy (CP-AFM) junctions with 50 nm(2) areas. We found that intensive observables agreed very well across the two junction platforms. Specifically, the EGaIn-based junctions showed: (i) a crossover from tunneling to hopping transport at molecular lengths near 4 nm; (ii) activated transport for wires >4 nm in length with an activation energy of 0.245 ± 0.008 eV for OPI-7; (iii) exponential dependence of conductance with molecular length with a decay constant β = 2.84 ± 0.18 nm(-1) (DC) and 2.92 ± 0.13 nm(-1) (AC) in the tunneling regime, and an apparent β = 1.01 ± 0.08 nm(-1) (DC) and 0.99 ± 0.11 nm(-1) (AC) in the hopping regime; (iv) previously unreported dielectric constant of 4.3 ± 0.2 along the OPI wires. However, the absolute resistances of Au-S-OPI//GaOx/EGaIn junctions were approximately 100 times higher than the corresponding CP-AFM junctions due to differences in metal-molecule contact resistances between the two platforms.

  17. Phagocytosis: receptors, signal integration, and the cytoskeleton.

    Science.gov (United States)

    Freeman, Spencer A; Grinstein, Sergio

    2014-11-01

    Phagocytosis is a remarkably complex and versatile process: it contributes to innate immunity through the ingestion and elimination of pathogens, while also being central to tissue homeostasis and remodeling by clearing effete cells. The ability of phagocytes to perform such diverse functions rests, in large part, on their vast repertoire of receptors. In this review, we address the various receptor types, their mobility in the plane of the membrane, and two modes of receptor crosstalk: priming and synergy. A major section is devoted to the actin cytoskeleton, which not only governs receptor mobility and clustering but also is instrumental in particle engulfment. Four stages of the actin remodeling process are identified and discussed: (i) the 'resting' stage that precedes receptor engagement, (ii) the disruption of the cortical actin prior to formation of the phagocytic cup, (iii) the actin polymerization that propels pseudopod extension, and (iv) the termination of polymerization and removal of preassembled actin that are required for focal delivery of endomembranes and phagosomal sealing. These topics are viewed in the larger context of the differentiation and polarization of the phagocytic cells.

  18. Tensegrity and mechanoregulation: from skeleton to cytoskeleton

    Science.gov (United States)

    Chen, C. S.; Ingber, D. E.

    1999-01-01

    OBJECTIVE: To elucidate how mechanical stresses that are applied to the whole organism are transmitted to individual cells and transduced into a biochemical response. DESIGN: In this article, we describe fundamental design principles that are used to stabilize the musculoskeletal system at many different size scales and show that these design features are embodied in one particular form of architecture that is known as tensegrity. RESULTS: Tensegrity structures are characterized by use of continuous tension and local compression; architecture, prestress (internal stress prior to application of external force), and triangulation play the most critical roles in terms of determining their mechanical stability. In living organisms, use of a hierarchy of tensegrity networks both optimizes structural efficiency and provides a mechanism to mechanically couple the parts with the whole: mechanical stresses applied at the macroscale result in structural rearrangements at the cell and molecular level. CONCLUSION: Due to use of tensegrity architecture, mechanical stress is concentrated and focused on signal transducing molecules that physically associate with cell surface molecules that anchor cells to extracellular matrix, such as integrins, and with load-bearing elements within the internal cytoskeleton and nucleus. Mechanochemical transduction may then proceed through local stress-dependent changes in molecular mechanics, thermodynamics, and kinetics within the cell. In this manner, the entire cellular response to stress may be orchestrated and tuned by altering the prestress in the cell, just as changing muscular tone can alter mechanical stability and structural coordination throughout the whole musculoskeletal system.

  19. Eukaryotic and Prokaryotic Cytoskeletons: Structure and Mechanics

    Science.gov (United States)

    Gopinathan, Ajay

    2013-03-01

    The eukaryotic cytoskeleton is an assembly of filamentous proteins and a host of associated proteins that collectively serve functional needs ranging from spatial organization and transport to the production and transmission of forces. These systems can exhibit a wide variety of non-equilibrium, self-assembled phases depending on context and function. While much recent progress has been made in understanding the self-organization, rheology and nonlinear mechanical properties of such active systems, in this talk, we will concentrate on some emerging aspects of cytoskeletal physics that are promising. One such aspect is the influence of cytoskeletal network topology and its dynamics on both active and passive intracellular transport. Another aspect we will highlight is the interplay between chirality of filaments, their elasticity and their interactions with the membrane that can lead to novel conformational states with functional implications. Finally we will consider homologs of cytoskeletal proteins in bacteria, which are involved in templating cell growth, segregating genetic material and force production, which we will discuss with particular reference to contractile forces during cell division. These prokaryotic structures function in remarkably similar yet fascinatingly different ways from their eukaryotic counterparts and can enrich our understanding of cytoskeletal functioning as a whole.

  20. The Role of Cytoskeleton in root gravisensing

    Science.gov (United States)

    Perbal, G.; Lefranc, A.; Jeune, B.; Driss-Ecole, D.

    It is well known that the perception time (minimal duration of a repeated stimulation to induce a response) is less than 1s. This implies that the statoliths must be very close to the cell structure that transmits the physical effect of gravistimulation to the mechanoreceptor. The actin network which is in contact with the statoliths could play this role. It has been shown recently that the actin filaments should be oriented at an angle of 130° with respect to the longitudinal wall, which could explain that a stimulation at 120-135° is more efficient than at 90° (this is called the deviation from the sine rule which states that graviresponsiveness should be greater at 90°). However, there are also arguments against the putative role of the actin filaments in the transduction of gravistimulus: several experiments have shown that a treatment by cytochalasin or latrunculin which perturbs the polymerisation of the actin filaments, does not prevent a gravitropic response. In the model that we propose, mechanoreceptors are connected together by elements of the cytoskeleton lining the longitudinal wall of the statocytes and they are also attached to the actin network. The statoliths could activate the mechanoreceptors by exerting tensions in this network or by exerting a pressure on the elements which are parallel to the longitudinal wall.

  1. Cytoskeleton, cytoskeletal interactions, and vascular endothelial function

    Directory of Open Access Journals (Sweden)

    Wang J

    2012-12-01

    Full Text Available Jingli Wang,1 Michael E Widlansky1,21Department of Medicine, Cardiovascular Medicine Division, 2Department of Pharmacology, Medical College of Wisconsin, Milwaukee, Wisconsin, USAAbstract: Far from being inert, the vascular endothelium is a critical regulator of vascular function. While the endothelium participates in autocrine, paracrine, and endocrine signaling, it also transduces mechanical signals from the cell surface involving key cell structural elements. In this review, we discuss the structure of the vascular endothelium and its relationship to traditional cardiovascular risk factors and clinical cardiovascular events. Further, we review the emerging evidence that cell structural elements, including the glycocalyx, intercellular junctions, and cytoskeleton elements, help the endothelium to communicate with its environment to regulate vascular function, including vessel permeability and signal transduction via nitric oxide bioavailability. Further work is necessary to better delineate the regulatory relationships between known key regulators of vascular function and endothelial cell structural elements.Keywords: endothelium, shear stress, eNOS, cardiovascular risk factors, glycocalyx

  2. MICAL, the Flavoenzyme Participating in Cytoskeleton Dynamics

    Directory of Open Access Journals (Sweden)

    Daniela Zucchini

    2013-03-01

    Full Text Available MICAL (from the Molecule Interacting with CasL indicates a family of recently discovered cytosolic, multidomain proteins, which uniquely couple an N-terminal FAD-containing monooxygenase-like domain to typical calponine homology, LIM and coiled-coil protein-interaction modules. Genetic and cell biology approaches have demonstrated an essential role of the catalytic activity of the monooxygenase-like domain in transducing the signal initiated by semaphorins interaction with their plexin receptors, which results in local actin cytoskeleton disassembly as part of fundamental processes that include differentiation, migration and cell-cell contacts in neuronal and non-neuronal cell types. This review focuses on the structure-function relations of the MICAL monooxygenase-like domain as they are emerging from the available in vitro studies on mouse, human and Drosophila MICAL forms that demonstrated a NADPH-dependent actin depolymerizing activity of MICAL. With Drosophila MICAL forms, actin depolymerization was demonstrated to be associated to conversion of Met44 to methionine sulfone through a postulated hydroxylating reaction. Arguments supporting the concept that MICAL effect on F-actin may be reversible will be discussed.

  3. Quantitative analyses of the plant cytoskeleton reveal underlying organizational principles

    CERN Document Server

    Breuer, David; Sampathkumar, Arun; Hollandt, Florian; Persson, Staffan; Nikoloski, Zoran

    2015-01-01

    The actin and microtubule cytoskeletons are vital structures for cell growth and development across all species. While individual molecular mechanisms underpinning actin and microtubule dynamics have been intensively studied, principles that govern the cytoskeleton organization remain largely unexplored. Here, we captured biologically relevant characteristics of the plant cytoskeleton through a network-driven imaging-based approach allowing to quantitatively assess dynamic features of the cytoskeleton. By introducing suitable null models, we demonstrate that the plant cytoskeletal networks exhibit properties required for efficient transport, namely, short average path lengths and high robustness. We further show that these advantageous features are maintained during temporal cytoskeletal re-arrangements. Interestingly, man-made transportation networks exhibit similar properties, suggesting general laws of network organization supporting diverse transport processes. The proposed network-driven analysis can be ...

  4. Powerful partnership: crosstalk between pannexin 1 and the cytoskeleton

    Directory of Open Access Journals (Sweden)

    Andrew Kenneth Jameson Boyce

    2014-01-01

    Full Text Available Pannexin 1 (Panx1 large-pore ion and metabolite channels are emerging as key proteins in many physiological and pathophysiological scenarios. Recent evidence has tightly linked Panx1 trafficking and function to the cytoskeleton, a multi-component network that provides critical structural support, transportation, and scaffolding functions in all cell types. Here we review early work demonstrating the mechanosensitive activation of Panx1 channels, and expand on more recent evidence directly linking Panx1 to the cytoskeleton. Further, we examine the reciprocal regulation between Panx1 and the cytoskeleton, and discuss the involvement of Panx1 in cytoskeletal-regulated cell behaviors. Finally, we identify important gaps in the current knowledge surrounding this emerging Panx1-cytoskeleton relationship.

  5. Roles for microtubule and microfilament cytoskeletons in animal cell cytokinesis

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhongcai; CAI Shang; JIANG Qing; ZHANG Chuanmao; TANG Xiaowei

    2005-01-01

    Microtubule and microfilament cytoskeletons play key roles in the whole process of cytokinesis. Although a number of hypotheses have been proposed to elucidate the mechanism of cytokinesis by microtubule and actin filament cytoskeletons, many reports are conflicting. In our study, combining the cytoskeletons drug treatments with the time-lapse video technology, we retested the key roles of microtubule and actin filament in cytokinesis. The results showed that depolymerization of microtubules by Nocodazole after the initiation of furrowing would not inhibit the furrow ingression, but obviously decrease the stiffness of daughter cells. Depolymerizing actin filaments by Cytochalasin B before metaphase would inhibit the initiation of furrowing but not chromosome segregation, resulting in the formation of binucleate cells; however, depolymerizing actin filaments during anaphase would prevent furrowing and lead to the regress of established furrow, also resulting in the formation of binucleate cells. Further, depolymerizing microtubules and actin filaments simultaneously after metaphase would cause the quick regress of the furrow and the formation of binucleate cells. From these results we propose that a successful cytokinesis requires functions and coordination of both the microtubule and actin filament cytoskeletons. Microtubule cytoskeleton may function in the positioning and initiation of cleavage furrow, and the actin filament cytoskeleton may play key roles in the initiation and ingression of the furrow.

  6. The Cytoskeleton and Force Response Mechanisms

    Science.gov (United States)

    Allen, Philip Goodwin

    2003-01-01

    The long term aim of this project was to define the mechanisms by which cells sense and respond to the physical forces experienced at 1g and missing in microgravity. Identification and characterization of the elements of the cells force response mechanism could provide pathways and molecules to serve as targets for pharmacological intervention to mitigate the pathologic effects of microgravity. Mechanical forces experienced by the organism can be transmitted to cells through molecules that allow cells to bind to the extracellular matrix and through other types of molecules which bind cells to each other. These molecules are coupled in large complexes of proteins to structural elements such as the actin cytoskeleton that give the cell the ability to sense, resist and respond to force. Application of small forces to tissue culture cells causes local elevation of intracellular calcium through stretch activated ion channels, increased tyrosine phosphorylation and a restructuring of the actin cytoskeleton. Using collagen coated iron oxide beads and strong magnets, we can apply different levels of force to cells in culture. We have found that force application causes the cells to polymerize actin at the site of mechanical deformation and unexpectedly, to depolymerize actin across the rest of the cell. Observations of GFP- actin expressing cells demonstrate that actin accumulates at the site of deformation within the first five minutes of force application and is maintained for many tens of minutes after force is removed. Consistent with the reinforcement of the cytoskeletal structures underlying the integrin-bead interaction, force also alters the motion of bound magnetic beads. This effect is seen following the removal of the magnetic field, and is only partially ablated by actin disruption with cytochalsin B. While actin is polymerizing locally at the site of force application, force also stimulates a global reduction in actin filament content within the cells. We have

  7. Self-assembled monolayers of Aβ peptides on Au electrodes: an artificial platform for probing the reactivity of redox active metals and cofactors relevant to Alzheimer's disease.

    Science.gov (United States)

    Pramanik, Debajyoti; Sengupta, Kushal; Mukherjee, Soumya; Dey, Somdatta Ghosh; Dey, Abhishek

    2012-07-25

    The water-soluble hydrophilic part of human Aβ peptide has been extended to include a C-terminal cysteine residue. Utilizing the thiol functionality of this cysteine residue, self-assembled monolayers (SAM) of these peptides are formed on Au electrodes. Atomic force microscopy imaging confirms formation of small Aβ aggregates on the surface of the electrode. These aggregates bind redox active metals like Cu and cofactors like heme, both of which are proposed to generate toxic partially reduced oxygen species (PROS) and play a vital role in Alzheimer's disease. The spectroscopic and electrochemical properties of these Cu and heme bound Aβ SAM are similar to those reported for the soluble Cu and heme bound Aβ peptide. Experiments performed on these Aβ-SAM electrodes clearly demonstrate that (1) heme bound Aβ is kinetically more competent in reducing O(2) than Cu bound Aβ, (2) under physiological conditions the reduced Cu site produces twice as much PROS (measured in situ) than the reduced heme site, and (3) chelators like clioquinol remove Cu from these aggregates, while drugs like methylene blue inhibit O(2) reactivity of the heme cofactor. This artificial construct provides a very easy platform for investigating potential drugs affecting aggregation of human Aβ peptides and PROS generation by its complexes with redox active metals and cofactors.

  8. NanoDLSay: a new platform technology for biomolecular detection and analysis using gold nanoparticle probes coupled with dynamic light scattering

    Science.gov (United States)

    Bogdanovic, Jelena; Huo, Qun

    2010-04-01

    Most analytical techniques that are routinely used in biomedical research for detection and quantification of biomolecules are time-consuming, expensive and labor-intensive, and there is always a need for rapid, affordable and convenient methods. Recently we have developed a new platform technology for biomolecular detection and analysis: NanoDLSay. NanoDLSay employs antibody-coated gold nanoparticles (GNPs) and dynamic light scattering, and correlates the specific increase in particle size after antigen-antibody interaction to the target antigen concentration. We applied this technology to develop an assay for rapid detection of actin, a protein widely used as a loading control in Western Blot analysis. GNPs were coated with two types of polyclonal anti-actin antibodies, and used in the assay to detect two types of actin: β- and bovine skeletal muscle actin in RIPA buffer. The results of our study revealed some complex aspects of actin binding characteristics, which depended on the type of actin reagent and anti-actin antibody used. A surprising finding was a reverse dose-response relationship between the actin concentration and the average particle size in the assay solution, which we attributed to the effect of RIPA buffer. Our results indicate that RIPA may also interfere in other types of nanoparticle-based assays, and that this interference deserves further study.

  9. Platform Constellations

    DEFF Research Database (Denmark)

    Staykova, Kalina Stefanova; Damsgaard, Jan

    2016-01-01

    This research paper presents an initial attempt to introduce and explain the emergence of new phenomenon, which we refer to as platform constellations. Functioning as highly modular systems, the platform constellations are collections of highly connected platforms which co-exist in parallel...... and as such allow us to study platforms not only as separate entities, but also to investigate the relationship between several platforms offered and governed by one and the same platform provider. By investigating two case studies of indigenous platform constellations formed around the hugely popular instant...... messaging apps KakaoTalk and LINE, we are able to gain valuable insights about the nature of these new constructions and to capture and synthesize their main characteristics in a framework. Our results show that platform constellations possess unique innovative capabilities, which can improve users...

  10. Dimensionality controls cytoskeleton assembly and metabolism of fibroblast cells in response to rigidity and shape.

    Directory of Open Access Journals (Sweden)

    Mirjam Ochsner

    Full Text Available BACKGROUND: Various physical parameters, including substrate rigidity, size of adhesive islands and micro-and nano-topographies, have been shown to differentially regulate cell fate in two-dimensional (2-D cell cultures. Cells anchored in a three-dimensional (3-D microenvironment show significantly altered phenotypes, from altered cell adhesions, to cell migration and differentiation. Yet, no systematic analysis has been performed that studied how the integrated cellular responses to the physical characteristics of the environment are regulated by dimensionality (2-D versus 3-D. METHODOLOGY/PRINCIPAL FINDINGS: Arrays of 5 or 10 microm deep microwells were fabricated in polydimethylsiloxane (PDMS. The actin cytoskeleton was compared for single primary fibroblasts adhering either to microfabricated adhesive islands (2-D or trapped in microwells (3-D of controlled size, shape, and wall rigidity. On rigid substrates (Young's Modulus = 1 MPa, cytoskeleton assembly within single fibroblast cells occurred in 3-D microwells of circular, rectangular, square, and triangular shapes with 2-D projected surface areas (microwell bottom surface area and total surface areas of adhesion (microwell bottom plus wall surface area that inhibited stress fiber assembly in 2-D. In contrast, cells did not assemble a detectable actin cytoskeleton in soft 3-D microwells (20 kPa, regardless of their shapes, but did so on flat, 2-D substrates. The dependency on environmental dimensionality was also reflected by cell viability and metabolism as probed by mitochondrial activities. Both were upregulated in 3-D cultured cells versus cells on 2-D patterns when surface area of adhesion and rigidity were held constant. CONCLUSION/SIGNIFICANCE: These data indicate that cell shape and rigidity are not orthogonal parameters directing cell fate. The sensory toolbox of cells integrates mechanical (rigidity and topographical (shape and dimensionality information differently when cell

  11. The Role of Actin Cytoskeleton in Memory Formation in Amygdala

    Directory of Open Access Journals (Sweden)

    Raphael eLamprecht

    2016-03-01

    Full Text Available The central, lateral and basolateral amygdala nuclei are essential for the formation of long-term memories including emotional and drug-related memories. The study of cellular and molecular mechanisms underpinning memory in amygdala may shed light on the formation of memory and on fear and addiction-related disorders. A challenge is to identify molecules activated by learning that subserve cellular changes needed for memory formation and maintenance in amygdala. Recent studies show that activation of synaptic receptors during fear and drug-related learning leads to alteration in actin cytoskeleton dynamics and structure in amygdala. Such changes in actin cytoskeleton in amygdala are essential for fear and drug-related memories formation. Moreover, the actin cytoskeleton subserves, after learning, changes in neuronal morphogenesis and glutamate receptors trafficking in amygdala. These cellular events are involved in fear and drug-related memories formation. Actin polymerization is also needed for the maintenance of drug-associated memories in amygdala. Thus, the actin cytoskeleton is a key mediator between receptor activation during learning and cellular changes subserving long-term memory in amygdala. The actin cytoskeleton may serve as a target for pharmacological treatment of fear memory associated with fear and anxiety disorders and drug addiction to prevent the debilitating consequences of these diseases.

  12. Diamagnetic levitation causes changes in the morphology, cytoskeleton, and focal adhesion proteins expression in osteocytes.

    Science.gov (United States)

    Qian, A R; Wang, L; Gao, X; Zhang, W; Hu, L F; Han, J; Li, J B; Di, S M; Shang, Peng

    2012-01-01

    Diamagnetic levitation technology is a novel simulated weightless technique and has recently been applied in life-science research. We have developed a superconducting magnet platform with large gradient high magnetic field (LG-HMF), which can provide three apparent gravity levels, namely, μg (diamagnetic levitation), 1g, and 2g for diamagnetic materials. In this study, the effects of LG-HMF on the activity, morphology, and cytoskeleton (actin filament, microtubules, and vimentin intermediate filaments) in osteocyte - like cell line MLO-Y4 were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) methods, hematoxylin-eosin (HE) staining, and laser scanning confocal microscopy (LSCM), respectively. The changes induced by LG-HMF in distribution and expression of focal adhesion (FA) proteins, including vinculin, paxillin, and talin in MLO-Y4 were determined by LSCM and Western blotting. The results showed that LG-HMF produced by superconducting magnet had no lethal effects on MLO-Y4. Compared to control, diamagnetic levitation (μg) affected MLO-Y4 morphology, nucleus size, cytoskeleton architecture, and FA proteins distribution and expression. The study indicates that osteocytes are sensitive to altered gravity and FA proteins (vinculin, paxillin, and talin) may be involved in osteocyte mechanosensation. The diamagnetic levitation may be a novel ground-based space-gravity simulator and can be used for biological experiment at cellular level. © 2011 IEEE

  13. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    2013-01-01

    Mobile probing is a method, developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time and space......). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings point...... to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face). The development...

  14. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    2012-01-01

    Mobile probing is a method, which has been developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time...... and space). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings...... point to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face...

  15. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    2012-01-01

    Mobile probing is a method, which has been developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time...... and space). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings...... point to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face...

  16. 计算机课程网络协作式开放实验教学模式探索%Probing into collaborative and open experiment teaching model based network platform on computer courses

    Institute of Scientific and Technical Information of China (English)

    廉佐政; 刘相娟; 李耀成; 陈淑鑫; 堵秀凤

    2013-01-01

    In order to improve the experiment teaching effect,probed into the computer courses experiment teaching method,and proposed open and collaborative network experiment teaching model.The teaching model based on network course platform,combined with collaborative learning,set up the elective system,to improve the teaching method and experiment contents and form.So the teaching model ensured the open and collaborative experiment course teaching,to improve students' innovative ability.%为了改善实验教学效果,探索了计算机课程实验教学方法,提出网络协作式开放实验教学模式。该教学模式以网络课程平台为基础,结合协作学习方式,建立了选课系统,对教学方式、实验内容进行改进。保障了实验课程的协作式开放教学,有利于提高学生创新能力。

  17. Formins: Bringing new insights to the organization of actin cytoskeleton

    Institute of Scientific and Technical Information of China (English)

    GUO Chunqing; REN Haiyun

    2006-01-01

    The actin cytoskeleton is an important component of eukaryotic cell cytoskeleton and is temporally and spatially controlled by a series of actin binding proteins (ABPs). Among ABPs, formin family proteins have attracted much attention as they can nucleate unbranched actin filament from the profilin bound actin pool in vivo. In recent years, a number of formin family members from different organisms have been reported, and their characteristics are known more clearly, although some questions are still to be clarified. Here, we summarize the structures, functions and nucleation mechanisms of different formin family proteins, intending to compare them and give some new clues to the study of formins.

  18. Computer Simulation of Cytoskeleton-Induced Blebbing in Lipid Membranes

    CERN Document Server

    Spangler, Eric J; Revalee, Joel D; Kumar, P B Sunil; Laradji, Mohamed

    2011-01-01

    Blebs are balloon-shaped membrane protrusions that form during many physiological processes. Using computer simulation of a particle-based model for self-assembled lipid bilayers coupled to an elastic meshwork, we investigated the phase behavior and kinetics of blebbing. We found that blebs form for large values of the ratio between the areas of the bilayer and the cytoskeleton. We also found that blebbing can be induced when the cytoskeleton is subject to a localized ablation or a uniform compression. The results obtained are qualitatively in agreement with the experimental evidence and the model opens up the possibility to study the kinetics of bleb formation in detail.

  19. From filaments to function:The role of the plant actin cytoskeleton in pathogen perception, signaling and immunity

    Institute of Scientific and Technical Information of China (English)

    Katie Porter; Brad Day

    2016-01-01

    The eukaryotic actin cytoskeleton is required for numerous cellular processes, including cell shape, develop-ment and movement, gene expression and signal transduc-tion, and response to biotic and abiotic stress. In recent years, research in both plants and animal systems have described a function for actin as the ideal surveillance platform, linking the function and activity of primary physiological processes to the immune system. In this review, we will highlight recent advances that have defined the regulation and breadth of function of the actin cytoskeleton as a network required for defense signaling following pathogen infection. Coupled with an overview of recent work demonstrating specific targeting of the plant actin cytoskeleton by a diversity of pathogens, including bacteria, fungi and viruses, we will highlight the importance of actin as a key signaling hub in plants, one that mediates surveillance of cellular homeostasis and the activa-tion of specific signaling responses following pathogen perception. B4ased on the studies highlighted herein, we propose a working model that posits changes in actin filament organization is in and of itself a highly specific signal, which induces, regulates and physically directs stimulus-specific signaling processes, most importantly, those associated with response to pathogens.

  20. Payment Platform

    DEFF Research Database (Denmark)

    Hjelholt, Morten; Damsgaard, Jan

    2012-01-01

    Payment transactions through the use of physical coins, bank notes or credit cards have for centuries been the standard formats of exchanging money. Recently online and mobile digital payment platforms has entered the stage as contenders to this position and possibly could penetrate societies...... thoroughly and substitute current payment standards in the decades to come. This paper portrays how digital payment platforms evolve in socio-technical niches and how various technological platforms aim for institutional attention in their attempt to challenge earlier platforms and standards. The paper...... applies a co-evolutionary multilevel perspective to model the interplay and processes between technology and society wherein digital payment platforms potentially will substitute other payment platforms just like the credit card negated the check. On this basis this paper formulate a multilevel conceptual...

  1. STED Nanoscopy Reveals the Ubiquity of Subcortical Cytoskeleton Periodicity in Living Neurons

    Directory of Open Access Journals (Sweden)

    Elisa D’Este

    2015-03-01

    Full Text Available In the axons of cultured hippocampal neurons, actin forms various structures, including bundles, patches (involved in the preservation of neuronal polarity, and a recently reported periodic ring-like structure. Nevertheless, the overlaying organization of actin in neurons and in the axon initial segment (AIS is still unclear, due mainly to a lack of adequate imaging methods. By harnessing live-cell stimulated emission depletion (STED nanoscopy and the fluorescent probe SiR-Actin, we show that the periodic subcortical actin structure is in fact present in both axons and dendrites. The periodic cytoskeleton organization is also found in the peripheral nervous system, specifically at the nodes of Ranvier. The actin patches in the AIS co-localize with pre-synaptic markers. Cytosolic actin organization strongly depends on the developmental stage and subcellular localization. Altogether, the results of this study reveal unique neuronal cytoskeletal features.

  2. STED nanoscopy reveals the ubiquity of subcortical cytoskeleton periodicity in living neurons.

    Science.gov (United States)

    D'Este, Elisa; Kamin, Dirk; Göttfert, Fabian; El-Hady, Ahmed; Hell, Stefan W

    2015-03-03

    In the axons of cultured hippocampal neurons, actin forms various structures, including bundles, patches (involved in the preservation of neuronal polarity), and a recently reported periodic ring-like structure. Nevertheless, the overlaying organization of actin in neurons and in the axon initial segment (AIS) is still unclear, due mainly to a lack of adequate imaging methods. By harnessing live-cell stimulated emission depletion (STED) nanoscopy and the fluorescent probe SiR-Actin, we show that the periodic subcortical actin structure is in fact present in both axons and dendrites. The periodic cytoskeleton organization is also found in the peripheral nervous system, specifically at the nodes of Ranvier. The actin patches in the AIS co-localize with pre-synaptic markers. Cytosolic actin organization strongly depends on the developmental stage and subcellular localization. Altogether, the results of this study reveal unique neuronal cytoskeletal features.

  3. The actin Cytoskeleton in Root Hairs: a cell elongation device

    NARCIS (Netherlands)

    Ketelaar, T.; Emons, A.M.C.

    2009-01-01

    The actin cytoskeleton plays an important role in root hair development. It is involved in both the delivery of growth materials to the expanding tip of root hairs and the regulation of the area of tip growth. This review starts with a discussion of the techniques that are available to visualize the

  4. Dynamics and Regulation of Actin Cytoskeleton in Plant Cells

    Institute of Scientific and Technical Information of China (English)

    Ren Haiyun

    2007-01-01

    @@ The actin cytoskeleton constituted of globular actin (G-actin) is a ubiquitous component of eukaryotic cells and plays crucial roles in diverse physiological processes in plant cells, such as cytoplasmic streaming, organelle and nucleus positioning, cell morphogenesis, cell division, tip growth, etc.

  5. Membrane tension and cytoskeleton organization in cell motility

    Science.gov (United States)

    Sens, Pierre; Plastino, Julie

    2015-07-01

    Cell membrane shape changes are important for many aspects of normal biological function, such as tissue development, wound healing and cell division and motility. Various disease states are associated with deregulation of how cells move and change shape, including notably tumor initiation and cancer cell metastasis. Cell motility is powered, in large part, by the controlled assembly and disassembly of the actin cytoskeleton. Much of this dynamic happens in close proximity to the plasma membrane due to the fact that actin assembly factors are membrane-bound, and thus actin filaments are generally oriented such that their growth occurs against or near the membrane. For a long time, the membrane was viewed as a relatively passive scaffold for signaling. However, results from the last five years show that this is not the whole picture, and that the dynamics of the actin cytoskeleton are intimately linked to the mechanics of the cell membrane. In this review, we summarize recent findings concerning the role of plasma membrane mechanics in cell cytoskeleton dynamics and architecture, showing that the cell membrane is not just an envelope or a barrier for actin assembly, but is a master regulator controlling cytoskeleton dynamics and cell polarity.

  6. The actin Cytoskeleton in Root Hairs: a cell elongation device

    NARCIS (Netherlands)

    Ketelaar, T.; Emons, A.M.C.

    2009-01-01

    The actin cytoskeleton plays an important role in root hair development. It is involved in both the delivery of growth materials to the expanding tip of root hairs and the regulation of the area of tip growth. This review starts with a discussion of the techniques that are available to visualize the

  7. The effect of cellular cholesterol on membrane-cytoskeleton adhesion.

    Science.gov (United States)

    Sun, Mingzhai; Northup, Nathan; Marga, Francoise; Huber, Tamas; Byfield, Fitzroy J; Levitan, Irena; Forgacs, Gabor

    2007-07-01

    Whereas recent studies suggest that cholesterol plays important role in the regulation of membrane proteins, its effect on the interaction of the cell membrane with the underlying cytoskeleton is not well understood. Here, we investigated this by measuring the forces needed to extract nanotubes (tethers) from the plasma membrane, using atomic force microscopy. The magnitude of these forces provided a direct measure of cell stiffness, cell membrane effective surface viscosity and association with the underlying cytoskeleton. Furthermore, we measured the lateral diffusion constant of a lipid analog DiIC12, using fluorescence recovery after photobleaching, which offers additional information on the organization of the membrane. We found that cholesterol depletion significantly increased the adhesion energy between the membrane and the cytoskeleton and decreased the membrane diffusion constant. An increase in cellular cholesterol to a level higher than that in control cells led to a decrease in the adhesion energy and the membrane surface viscosity. Disassembly of the actin network abrogated all the observed effects, suggesting that cholesterol affects the mechanical properties of a cell through the underlying cytoskeleton. The results of these quantitative studies may help to better understand the biomechanical processes accompanying the development of atherosclerosis.

  8. Coping with loss: cell adaptation to cytoskeleton disruption

    OpenAIRE

    McGarry, David J.; Olson, Michael F

    2016-01-01

    Unravelling the role of cytoskeleton regulators may be complicated by adaptations to experimental manipulations. In this issue of Developmental Cell, Cerikan et al. (2016) reveal how acute effects of DOCK6 RhoGEF depletion on RAC1 and CDC42 activation are reversed over time by compensatory mechanisms that re-establish cellular homeostasis.

  9. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    2013-01-01

    to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face). The development...

  10. Helium ion microscopy and ultra-high-resolution scanning electron microscopy analysis of membrane-extracted cells reveals novel characteristics of the cytoskeleton of Giardia intestinalis.

    Science.gov (United States)

    Gadelha, Ana Paula Rocha; Benchimol, Marlene; de Souza, Wanderley

    2015-06-01

    Giardia intestinalis presents a complex microtubular cytoskeleton formed by specialized structures, such as the adhesive disk, four pairs of flagella, the funis and the median body. The ultrastructural organization of the Giardia cytoskeleton has been analyzed using different microscopic techniques, including high-resolution scanning electron microscopy. Recent advances in scanning microscopy technology have opened a new venue for the characterization of cellular structures and include scanning probe microscopy techniques such as ultra-high-resolution scanning electron microscopy (UHRSEM) and helium ion microscopy (HIM). Here, we studied the organization of the cytoskeleton of G. intestinalis trophozoites using UHRSEM and HIM in membrane-extracted cells. The results revealed a number of new cytoskeletal elements associated with the lateral crest and the dorsal surface of the parasite. The fine structure of the banded collar was also observed. The marginal plates were seen linked to a network of filaments, which were continuous with filaments parallel to the main cell axis. Cytoplasmic filaments that supported the internal structures were seen by the first time. Using anti-actin antibody, we observed a labeling in these filamentous structures. Taken together, these data revealed new surface characteristics of the cytoskeleton of G. intestinalis and may contribute to an improved understanding of the structural organization of trophozoites.

  11. [Lens platform].

    Science.gov (United States)

    Łukaszewska-Smyk, Agnieszka; Kałuzny, Józef

    2010-01-01

    The lens platform defines lens structure and lens material. Evolution of lens comprises change in their shape, angulation of haptens and transition of three-piece lens into one-piece lens. The lens fall into two categories: rigid (PMMA) and soft (siliconic, acrylic, colameric). The main lens maaterials are polymers (hydrophilic and hydrophobic). The lens platform has an effect on biocompatibility, bioadhesion, stability of lens in capsule, degree of PCO evolution and sensitiveness to laser damages.

  12. Platform contents

    OpenAIRE

    Renault, Régis

    2014-01-01

    A monopoly platform hosts advertisers who compete on a market for horizontally differentiated products. These products may be either mass market products that appeal broadly to the entire consumer population or niche products that are tailored to the tastes of some particular group. Consumers search sequentially through ads incurring a surfing cost of moving to the next ad. They may click on an ad at some cost, which provides all relevant information and the opportunity to buy. The platform c...

  13. Desmosome dynamics in migrating epithelial cells requires the actin cytoskeleton

    Science.gov (United States)

    Roberts, Brett J.; Pashaj, Anjeza; Johnson, Keith R.; Wahl, James K.

    2011-01-01

    Re-modeling of epithelial tissues requires that the cells in the tissue rearrange their adhesive contacts in order to allow cells to migrate relative to neighboring cells. Desmosomes are prominent adhesive structures found in a variety of epithelial tissues that are believed to inhibit cell migration and invasion. Mechanisms regulating desmosome assembly and stability in migrating cells are largely unknown. In this study we established a cell culture model to examine the fate of desmosomal components during scratch wound migration. Desmosomes are rapidly assembled between epithelial cells at the lateral edges of migrating cells and structures are transported in a retrograde fashion while the structures become larger and mature. Desmosome assembly and dynamics in this system are dependent on the actin cytoskeleton prior to being associated with the keratin intermediate filament cytoskeleton. These studies extend our understanding of desmosome assembly and provide a system to examine desmosome assembly and dynamics during epithelial cell migration. PMID:21945137

  14. Mechanotransduction Across the Cell Surface and Through the Cytoskeleton

    Science.gov (United States)

    Wang, Ning; Butler, James P.; Ingber, Donald E.

    1993-05-01

    Mechanical stresses were applied directly to cell surface receptors with a magnetic twisting device. The extracellular matrix receptor, integrin β_1, induced focal adhesion formation and supported a force-dependent stiffening response, whereas nonadhesion receptors did not. The cytoskeletal stiffness (ratio of stress to strain) increased in direct proportion to the applied stress and required intact microtubules and intermediate filaments as well as microfilaments. Tensegrity models that incorporate mechanically interdependent struts and strings that reorient globally in response to a localized stress mimicked this response. These results suggest that integrins act as mechanoreceptors and transmit mechanical signals to the cytoskeleton. Mechanotransduction, in turn, may be mediated simultaneously at multiple locations inside the cell through force-induced rearrangements within a tensionally integrated cytoskeleton.

  15. Direct Cytoskeleton Forces Cause Membrane Softening in Red Blood Cells

    Science.gov (United States)

    Rodríguez-García, Ruddi; López-Montero, Iván; Mell, Michael; Egea, Gustavo; Gov, Nir S.; Monroy, Francisco

    2015-01-01

    Erythrocytes are flexible cells specialized in the systemic transport of oxygen in vertebrates. This physiological function is connected to their outstanding ability to deform in passing through narrow capillaries. In recent years, there has been an influx of experimental evidence of enhanced cell-shape fluctuations related to metabolically driven activity of the erythroid membrane skeleton. However, no direct observation of the active cytoskeleton forces has yet been reported to our knowledge. Here, we show experimental evidence of the presence of temporally correlated forces superposed over the thermal fluctuations of the erythrocyte membrane. These forces are ATP-dependent and drive enhanced flickering motions in human erythrocytes. Theoretical analyses provide support for a direct force exerted on the membrane by the cytoskeleton nodes as pulses of well-defined average duration. In addition, such metabolically regulated active forces cause global membrane softening, a mechanical attribute related to the functional erythroid deformability. PMID:26083919

  16. Self-assembling enzymes and the origins of the cytoskeleton

    Science.gov (United States)

    Barry, Rachael; Gitai, Zemer

    2011-01-01

    The bacterial cytoskeleton is composed of a complex and diverse group of proteins that self-assemble into linear filaments. These filaments support and organize cellular architecture and provide a dynamic network controlling transport and localization within the cell. Here, we review recent discoveries related to a newly appreciated class of self-assembling proteins that expand our view of the bacterial cytoskeleton and provide potential explanations for its evolutionary origins. Specifically, several types of metabolic enzymes can form structures similar to established cytoskeletal filaments and, in some cases, these structures have been repurposed for structural uses independent of their normal role. The behaviors of these enzymes suggest that some modern cytoskeletal proteins may have evolved from dual-role proteins with catalytic and structural functions. PMID:22014508

  17. "Panta rhei": Perpetual cycling of the keratin cytoskeleton.

    Science.gov (United States)

    Leube, Rudolf E; Moch, Marcin; Kölsch, Anne; Windoffer, Reinhard

    2011-01-01

    The filamentous cytoskeletal systems fulfil seemingly incompatible functions by maintaining a stable scaffolding to ensure tissue integrity and simultaneously facilitating rapid adaptation to intracellular processes and environmental stimuli. This paradox is particularly obvious for the abundant keratin intermediate filaments in epithelial tissues. The epidermal keratin cytoskeleton, for example, supports the protective and selective barrier function of the skin while enabling rapid growth and remodelling in response to physical, chemical and microbial challenges. We propose that these dynamic properties are linked to the perpetual re-cycling of keratin intermediate filaments that we observe in cultured cells. This cycle of assembly and disassembly is independent of protein biosynthesis and consists of distinct, temporally and spatially defined steps. In this way, the keratin cytoskeleton remains in constant motion but stays intact and is also able to restructure rapidly in response to specific regulatory cues as is needed, e.g., during division, differentiation and wound healing.

  18. Prokaryotic cells: structural organisation of the cytoskeleton and organelles

    OpenAIRE

    Wanderley de Souza

    2012-01-01

    For many years, prokaryotic cells were distinguished from eukaryotic cells based on the simplicity of their cytoplasm, in which the presence of organelles and cytoskeletal structures had not been discovered. Based on current knowledge, this review describes the complex components of the prokaryotic cell cytoskeleton, including (i) tubulin homologues composed of FtsZ, BtuA, BtuB and several associated proteins, which play a fundamental role in cell division, (ii) actin-like homologues, such as...

  19. Proteomics and the Trypanosoma brucei cytoskeleton: advances and opportunities.

    Science.gov (United States)

    Portman, Neil; Gull, Keith

    2012-08-01

    Trypanosoma brucei is the etiological agent of devastating parasitic disease in humans and livestock in sub-saharan Africa. The pathogenicity and growth of the parasite are intimately linked to its shape and form. This is in turn derived from a highly ordered microtubule cytoskeleton that forms a tightly arrayed cage directly beneath the pellicular membrane and numerous other cytoskeletal structures such as the flagellum. The parasite undergoes extreme changes in cellular morphology during its life cycle and cell cycles which require a high level of integration and coordination of cytoskeletal processes. In this review we will discuss the role that proteomics techniques have had in advancing our understanding of the molecular composition of the cytoskeleton and its functions. We then consider future opportunities for the application of these techniques in terms of addressing some of the unanswered questions of trypanosome cytoskeletal cell biology with particular focus on the differences in the composition and organisation of the cytoskeleton through the trypanosome life-cycle.

  20. Multiscale modeling and mechanics of filamentous actin cytoskeleton.

    Science.gov (United States)

    Yamaoka, Hidetaka; Matsushita, Shinji; Shimada, Yoshitaka; Adachi, Taiji

    2012-03-01

    The adaptive structure and functional changes of the actin cytoskeleton are induced by its mechanical behavior at various temporal and spatial scales. In particular, the mechanical behaviors at different scales play important roles in the mechanical functions of various cells, and these multiscale phenomena require clarification. To establish a milestone toward achieving multiscale modeling and simulation, this paper reviews mathematical analyses and simulation methods applied to the mechanics of the filamentous actin cytoskeleton. The actin cytoskeleton demonstrates characteristic behaviors at every temporal and spatial scale, and mathematical models and simulation methods can be applied to each level of actin cytoskeletal structure ranging from the molecular to the network level. This paper considers studies on mathematical models and simulation methods based on the molecular dynamics, coarse-graining, and continuum dynamics approaches. Every temporal and spatial scale of actin cytoskeletal structure is considered, and it is expected that discrete and continuum dynamics ranging from functional expression at the molecular level to macroscopic functional expression at the whole cell level will be developed and applied to multiscale modeling and simulation.

  1. Actin cytoskeleton remodeling governs aquaporin-4 localization in astrocytes.

    Science.gov (United States)

    Nicchia, Grazia Paola; Rossi, Andrea; Mola, Maria Grazia; Procino, Giuseppe; Frigeri, Antonio; Svelto, Maria

    2008-12-01

    Aquaporin-4 (AQP4) is constitutively concentrated in the plasma membrane of the perivascular glial processes, and its expression is altered in certain pathological conditions associated with brain edema or altered glial migration. When astrocytes are grown in culture, they lose their characteristic star-like shape and AQP4 continuous plasma membrane localization observed in vivo. In this study, we differentiated primary astrocyte cultures with cAMP and lovastatin, both able to induce glial stellation through a reorganization of F-actin cytoskeleton, and obtained AQP4 selectively localized on the cell plasma membrane associated with an increase in the plasma membrane water transport level, but only cAMP induced an increase in AQP4 total protein expression. Phosphorylation experiments indicated that AQP4 in astrocytes is neither phosphorylated nor a substrate of PKA. Depolymerization of F-actin cytoskeleton performed by cytochalasin-D suggested that F-actin cytoskeleton plays a primary role for AQP4 plasma membrane localization and during cell adhesion. Finally, AQP4 knockdown does not compromise the ability of astrocytes to stellate in the presence of cAMP, indicating that astrocyte stellation is independent of AQP4. Copyright 2008 Wiley-Liss, Inc.

  2. How cellular membrane properties are affected by the actin cytoskeleton.

    Science.gov (United States)

    Lemière, J; Valentino, F; Campillo, C; Sykes, C

    2016-11-01

    Lipid membranes define the boundaries of living cells and intracellular compartments. The dynamic remodelling of these membranes by the cytoskeleton, a very dynamic structure made of active biopolymers, is crucial in many biological processes such as motility or division. In this review, we present some aspects of cellular membranes and how they are affected by the presence of the actin cytoskeleton. We show that, in parallel with the direct study of membranes and cytoskeleton in vivo, biomimetic in vitro systems allow reconstitution of biological processes in a controlled environment. In particular, we show that liposomes, or giant unilamellar vesicles, encapsulating a reconstituted actin network polymerizing at their membrane are suitable models of living cells and can be used to decipher the relative contributions of membrane and actin on the mechanical properties of the cellular interface. Copyright © 2016 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  3. A Role for the Cytoskeleton in Heart Looping

    Directory of Open Access Journals (Sweden)

    Kersti K. Linask

    2007-01-01

    Full Text Available Over the past 10 years, key genes involved in specification of left-right laterality pathways in the embryo have been defined. The read-out for misexpression of laterality genes is usually the direction of heart looping. The question of how dextral looping direction occurred mechanistically and how the heart tube bends remains unknown. It is becoming clear from our experiments and those of others that left-right differences in cell proliferation in the second heart field (anterior heart field drives the dextral direction. Evidence is accumulating that the cytoskeleton is at the center of laterality, and the bending and rotational forces associated with heart looping. If laterality pathways are modulated upstream, the cytoskeleton, including nonmuscle myosin II (NMHC-II, is altered downstream within the cardiomyocytes, leading to looping abnormalities. The cytoskeleton is associated with important mechanosensing and signaling pathways in cell biology and development. The initiation of blood flow during the looping period and the inherent stresses associated with increasing volumes of blood flowing into the heart may help to potentiate the process. In recent years, the steps involved in this central and complex process of heart development that is the basis of numerous congenital heart defects are being unraveled.

  4. ITS Platform

    DEFF Research Database (Denmark)

    Tøfting, Svend; Lahrmann, Harry; Agerholm, Niels

    2014-01-01

    Aalborg University and two local companies have over the past four years developed and tested an ITS Platform, which can be used for communication with cars and for providing a number of services to the drivers. The purpose has been to perform a technological test of the possible use of a hidden ...... not have to be very intelligent. This is gradually taken over by applications on smart phones. The ITS Platform with 425 test drivers is now completely developed and can be used for technological testing of e.g. payment systems.......Aalborg University and two local companies have over the past four years developed and tested an ITS Platform, which can be used for communication with cars and for providing a number of services to the drivers. The purpose has been to perform a technological test of the possible use of a hidden...

  5. ITS Platform

    DEFF Research Database (Denmark)

    Tøfting, Svend; Lahrmann, Harry; Agerholm, Niels

    2014-01-01

    Aalborg University and two local companies have over the past four years developed and tested an ITS Platform, which can be used for communication with cars and for providing a number of services to the drivers. The purpose has been to perform a technological test of the possible use of a hidden ...... not have to be very intelligent. This is gradually taken over by applications on smart phones. The ITS Platform with 425 test drivers is now completely developed and can be used for technological testing of e.g. payment systems....

  6. Platform computing

    CERN Multimedia

    2002-01-01

    "Platform Computing releases first grid-enabled workload management solution for IBM eServer Intel and UNIX high performance computing clusters. This Out-of-the-box solution maximizes the performance and capability of applications on IBM HPC clusters" (1/2 page) .

  7. Current meter components and other data from FIXED PLATFORMS in support of the Processes and Resources of the Bering Sea Shelf (PROBES) project from 27 April 1977 to 01 November 1978 (NODC Accession 8400221)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter components data were collected from FIXED PLATFORMS from 22 February 1992 to 18 February 1993. Data were collected by the University of Alaska -...

  8. Structural insights into bacterial modulation of the host cytoskeleton.

    Science.gov (United States)

    Stebbins, C Erec

    2004-12-01

    Many bacterial pathogens manipulate the host cell cytoskeleton during infection. Such cytoskeletal modulation can occur at several points of contact between the pathogen and the host, and involves extracellular receptors, intracellular signal transduction and cytoskeletal proteins themselves. The field of bacterial pathogenesis has progressed dramatically over the past decade, such that structural knowledge is both timely and essential for a full appreciation of the biology at the pathogen-host interface. Several recent examples involving bacterial proteins that target actin, Rho family GTPases and extracellular receptors have contributed to a structural understanding of eukaryotic cytoskeletal modulation by pathogens.

  9. Exploring the Cytoskeleton During Intracytoplasmic Sperm Injection in Humans

    Science.gov (United States)

    Rawe, Vanesa Y.; Chemes, Héctor

    Understanding the cellular events during fertilization in mammals is a major challenge that can contribute to the improvement of future infertility treatments in humans and reproductive performance in farm animals. Of special interest is the role of the oocyte and sperm cytoskeleton during the initial interaction between gametes. The aim of this chapter is to describe methods for studying cytoskeletal features during in vitro fertilization after intracytoplasmic sperm injection (ICSI) in humans. The following protocols will provide a detailed description of how to perform immunodetection and imaging of human eggs, zygotes, and sperm by fluorescence (confocal and epifluorescence) and electron microscopy.

  10. Platform Constellations

    DEFF Research Database (Denmark)

    Staykova, Kalina Stefanova; Damsgaard, Jan

    2016-01-01

    messaging apps KakaoTalk and LINE, we are able to gain valuable insights about the nature of these new constructions and to capture and synthesize their main characteristics in a framework. Our results show that platform constellations possess unique innovative capabilities, which can improve users......’ acquisition and users’ engagement rates as well as unlock new sources of value creation and diversify revenue streams....

  11. New EMBO members' review: actin cytoskeleton regulation through modulation of PI(4,5)P(2) rafts.

    Science.gov (United States)

    Caroni, P

    2001-08-15

    The phosphoinositide lipid PI(4,5)P(2) is now established as a key cofactor in signaling to the actin cytoskeleton and in vesicle trafficking. PI(4,5)P(2) accumulates at membrane rafts and promotes local co-recruitment and activation of specific signaling components at the cell membrane. PI(4,5)P(2) rafts may thus be platforms for local regulation of morphogenetic activity at the cell membrane. Raft PI(4,5)P(2) is regulated by lipid kinases (PI5-kinases) and lipid phosphatases (e.g. synaptojanin). In addition, GAP43-like proteins have recently emerged as a group of PI(4,5)P(2) raft-modulating proteins. These locally abundant proteins accumulate at inner leaflet plasmalemmal rafts where they bind to and co-distribute with PI(4,5)P(2), and promote actin cytoskeleton accumulation and dynamics. In keeping with their proposed role as positive modulators of PI(4,5)P(2) raft function, GAP43-like proteins confer competence for regulated morphogenetic activity on cells that express them. Their function has been investigated extensively in the nervous system, where their expression promotes neurite outgrowth, anatomical plasticity and nerve regeneration. Extrinsic signals and intrinsic factors may thus converge to modulate PI(4,5)P(2) rafts, upstream of regulated activity at the cell surface.

  12. Chirality of the cytoskeleton in the origins of cellular asymmetry.

    Science.gov (United States)

    Satir, Peter

    2016-12-19

    Self-assembly of two important components of the cytoskeleton of eukaryotic cells, actin microfilaments and microtubules (MTs) results in polar filaments of one chirality. As is true for bacterial flagella, in actin microfilaments, screw direction is important for assembly processes and motility. For MTs, polar orientation within the cell is paramount. The alignment of these elements in the cell cytoplasm gives rise to emergent properties, including the potential for cell differentiation and specialization. Complex MTs with a characteristic chirality are found in basal bodies and centrioles; this chirality is preserved in cilia. In motile cilia, it is reflected in the direction of the effective stroke. The positioning of the basal body or cilia on the cell surface depends on polarity proteins. In evolution, survival depends on global polarity information relayed to the cell in part by orientation of the MT and actin filament cytoskeletons and the chirality of the basal body to determine left and right coordinates within a defined anterior-posterior cell and tissue axis.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.

  13. The importance of the smooth muscle cytoskeleton to preterm labour.

    Science.gov (United States)

    Morgan, Kathleen G

    2014-03-01

    Multiple mechanisms have been shown to regulate the onset of labour in a co-operative and complex manner. One factor, myometrial stretch and associated increases in wall tension, has been implicated clinically in the initiation of labour and especially the aetiology of preterm labour. Recent work on the mechanisms involved has led to the finding that the intracellular Ca(2+) requirement for activation of the myometrial contractile filaments increases during gestation. The decreased Ca(2+) sensitivity correlates with an increase in the expression of caldesmon, an actin-binding protein and inhibitor of myosin activation, during pregnancy. In late pregnancy, an increase in extracellular signal-regulated kinase-mediated caldesmon phosphorylation occurs, which appears to reverse the inhibitory action of caldesmon during labour. Force generated by the myometrial contractile filaments is communicated across the plasmalemma to the uterine wall through focal adhesions. Phospho-tyrosine screening and mass spectrometry of stretched myometrial samples identified several stretch-activated focal adhesion proteins. This Src-mediated focal adhesion signalling appears to provide a tunable, i.e. regulated, tension sensor and force transmitter in the myometrial cell. In other parallel studies, biophysical measurements of smooth muscle compliance at both the cellular and tissue levels suggest that decreases in cellular compliance due to changing interactions of the actin cytoskeleton with the focal adhesions may also promote increases in uterine wall tension. These results, taken together, suggest that focal adhesion proteins and their interaction with the cytoskeleton may present a new mode of regulation of uterine contractility.

  14. Interconnection between actin cytoskeleton and plant defense signaling.

    Science.gov (United States)

    Janda, Martin; Matoušková, Jindřiška; Burketová, Lenka; Valentová, Olga

    2014-01-01

    Actin cytoskeleton is the fundamental structural component of eukaryotic cells. It has a role in numerous elementary cellular processes such as reproduction, development and also in response to abiotic and biotic stimuli. Remarkably, the role of actin cytoskeleton in plant response to pathogens is getting to be under magnifying glass. Based on microscopic studies, most of the data showed, that actin plays an important role in formation of physiological barrier in the site of infection. Actin dynamics is involved in the transport of antimicrobial compounds and cell wall fortifying components (e.g. callose) to the site of infection. Also the role in PTI (pathogen triggered immunity) and ETI (effector triggered immunity) was recently indicated. On the other hand much less is known about the transcriptome reprogramming upon changes in actin dynamics. Our recently published results showed that drugs inhibiting actin polymerization (latrunculin B, cytochalasin E) cause the induction of genes which are involved in salicylic acid (SA) signaling pathway. In this addendum we would like to highlight in more details current state of knowledge concerning the involvement of actin dynamics in plant defense signaling.

  15. Calpains mediate axonal cytoskeleton disintegration during Wallerian degeneration.

    Science.gov (United States)

    Ma, Marek; Ferguson, Toby A; Schoch, Kathleen M; Li, Jian; Qian, Yaping; Shofer, Frances S; Saatman, Kathryn E; Neumar, Robert W

    2013-08-01

    In both the central nervous system (CNS) and peripheral nervous system (PNS), transected axons undergo Wallerian degeneration. Even though Augustus Waller first described this process after transection of axons in 1850, the molecular mechanisms may be shared, at least in part, by many human diseases. Early pathology includes failure of synaptic transmission, target denervation, and granular disintegration of the axonal cytoskeleton (GDC). The Ca(2+)-dependent protease calpains have been implicated in GDC but causality has not been established. To test the hypothesis that calpains play a causal role in axonal and synaptic degeneration in vivo, we studied transgenic mice that express human calpastatin (hCAST), the endogenous calpain inhibitor, in optic and sciatic nerve axons. Five days after optic nerve transection and 48 h after sciatic nerve transection, robust neurofilament proteolysis observed in wild-type controls was reduced in hCAST transgenic mice. Protection of the axonal cytoskeleton in sciatic nerves of hCAST mice was nearly complete 48 h post-transection. In addition, hCAST expression preserved the morphological integrity of neuromuscular junctions. However, compound muscle action potential amplitudes after nerve transection were similar in wild-type and hCAST mice. These results, in total, provide direct evidence that calpains are responsible for the morphological degeneration of the axon and synapse during Wallerian degeneration.

  16. Effects of polar cortical cytoskeleton and unbalanced cortical surface tension on intercellular bridge thinning during cytokinesis

    Institute of Scientific and Technical Information of China (English)

    Li Wang; Mei-Wen An; Xiao-Na Li; Fang Yang; Yang Liu

    2011-01-01

    To probe the contributions of polar cortical cytoskeleton and the surface tension of daughter cells to intercellular bridgethinning dynamics during cytokinesis,we applied cytochalasin D (CD) or colchicine (COLC) in a highly localized manner to polar regions of dividing normal rat kidney (NRK) cells.We observed cellular morphological changes and analyzed the intercellular bridge thinning trajectories of dividing cells with different polar cortical characteristics.Global blebbistatin (BS) application was used to obtain cells losing active contractile force groups.Our results show that locally released CD or colchicine at the polar region caused inhibition of cytokinesis before ingression.Similar treatment at phases after ingression allowed completion of cytokinesis but dramatically influenced the trajectories of intercellular bridge thinning.Disturbing single polar cortical actin induced transformation of the intercellular bridge thinning process,and polar cortical tension controlled deformation time of intercellular bridges.Our study provides a feasible framework to induce and analyze the effects of local changes in mechanical properties of cellular components on single cellular cytokinesis.

  17. SERS diagnostic platforms, methods and systems microarrays, biosensors and biochips

    Energy Technology Data Exchange (ETDEWEB)

    Vo-Dinh, Tuan (Knoxville, TN)

    2007-09-11

    A Raman integrated sensor system for the detection of targets including biotargets includes at least one sampling platform, at least one receptor probe disposed on the sampling platform, and an integrated circuit detector system communicably connected to the receptor. The sampling platform is preferably a Raman active surface-enhanced scattering (SERS) platform, wherein the Raman sensor is a SERS sensor. The receptors can include at least one protein receptor and at least one nucleic acid receptor.

  18. SERS diagnostic platforms, methods and systems microarrays, biosensors and biochips

    Science.gov (United States)

    Vo-Dinh, Tuan

    2007-09-11

    A Raman integrated sensor system for the detection of targets including biotargets includes at least one sampling platform, at least one receptor probe disposed on the sampling platform, and an integrated circuit detector system communicably connected to the receptor. The sampling platform is preferably a Raman active surface-enhanced scattering (SERS) platform, wherein the Raman sensor is a SERS sensor. The receptors can include at least one protein receptor and at least one nucleic acid receptor.

  19. Probe Storage

    NARCIS (Netherlands)

    Gemelli, Marcellino; Abelmann, Leon; Engelen, Johan B.C.; Khatib, Mohammed G.; Koelmans, Wabe W.; Zaboronski, Olog; Campardo, Giovanni; Tiziani, Federico; Laculo, Massimo

    2011-01-01

    This chapter gives an overview of probe-based data storage research over the last three decades, encompassing all aspects of a probe recording system. Following the division found in all mechanically addressed storage systems, the different subsystems (media, read/write heads, positioning, data chan

  20. Cultural probes

    DEFF Research Database (Denmark)

    Madsen, Jacob Østergaard

    2016-01-01

    The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation.......The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation....

  1. Less is more: removing membrane attachments stiffens the RBC cytoskeleton

    Energy Technology Data Exchange (ETDEWEB)

    Gov, Nir S [Department of Chemical Physics, The Weizmann Institute of Science, PO Box 26, Rehovot 76100 (Israel)

    2007-11-15

    The polymerized network of the cytoskeleton of the red-blood cell (RBC) contains different protein components that maintain its overall integrity and attachment to the lipid bilayer. One of these key components is the band 3-ankyrin complex that attaches the spectrin filaments to the fluid bilayer. Defects in this particular component result in the shape transformation called spherocytosis, through the shedding of membrane nano-vesicles. We show here that this transition and membrane shedding can be explained through the increased stiffness of the network when the band 3-ankyrin complexes are removed. ATP-induced transient dissociations lead to network softening, which offsets the stiffening to some extent, and causes increased fragility of these mutant cells, as is observed.

  2. The paranodal cytoskeleton clusters Na(+) channels at nodes of Ranvier.

    Science.gov (United States)

    Amor, Veronique; Zhang, Chuansheng; Vainshtein, Anna; Zhang, Ao; Zollinger, Daniel R; Eshed-Eisenbach, Yael; Brophy, Peter J; Rasband, Matthew N; Peles, Elior

    2017-01-30

    A high density of Na(+) channels at nodes of Ranvier is necessary for rapid and efficient action potential propagation in myelinated axons. Na+ channel clustering is thought to depend on two axonal cell adhesion molecules that mediate interactions between the axon and myelinating glia at the nodal gap (i.e., NF186) and the paranodal junction (i.e., Caspr). Here we show that while Na(+) channels cluster at nodes in the absence of NF186, they fail to do so in double conditional knockout mice lacking both NF186 and the paranodal cell adhesion molecule Caspr, demonstrating that a paranodal junction-dependent mechanism can cluster Na(+) channels at nodes. Furthermore, we show that paranode-dependent clustering of nodal Na(+) channels requires axonal βII spectrin which is concentrated at paranodes. Our results reveal that the paranodal junction-dependent mechanism of Na(+)channel clustering is mediated by the spectrin-based paranodal axonal cytoskeleton.

  3. Role of the cytoskeleton in nucleocytoplasmic RNA and protein distributions.

    Science.gov (United States)

    Agutter, P S

    1991-11-01

    Establishment and maintenance of correct partitioning of proteins and RNA molecules between nucleus and cytoplasm in a sine qua non of the viability of eukaryotic cells. Cytoskeletal elements play several roles in such partitioning: controlling the diffusion of proteins within the main cell compartments; presenting transportable macromolecular ligands to receptor sites within the pore complexes; maintaining the structure and dynamics of the pore complexes themselves. The solid-state transport machinery which moves mRNA molecules between particular sites in nucleus and cytoplasm is dependent on actin and other fibrils, and the migration of other major RNA types might show similar dependence. These various aspects of macromolecule partitioning illustrate one way in which the cytoskeleton is fundamental to the eukaryotic state.

  4. The cytoskeleton of digitonin-treated rat hepatocytes.

    Science.gov (United States)

    Fiskum, G; Craig, S W; Decker, G L; Lehninger, A L

    1980-06-01

    Treatment of isolated rat hepatocptes with low concentrations of digitonin increases the permeability of the plsma membrane to cytosolic proteins without causing release of organelles such as mitochondria into the surrounding medium. Electron microscopy showed that treatment of the cells with increasing concentations of digitonin results in a progressive loss in the continuity of the plasma membrane, while most other aspects of cellular morphology remain normal. Depletion of background staining material from the cytosol by digitonin treatment of the cells greatly enhances the visualization of the cytoskeleton. The use of this technique, together with immunofluorescent light microscopy, has verified the presence of an actin-containing filamentous network at the hepatocyte cortex as well as intermediate filaments distributed throughout the cell. Digitonin is thus useful both for selectively permeabilizing the plasma membrane and for intensifying the appearance of intracellular structures such as microfilaments that are normally difficult to observe in cells such as hepatocytes.

  5. Role of plectin in cytoskeleton organization and dynamics.

    Science.gov (United States)

    Wiche, G

    1998-09-01

    Plectin and its isoforms are versatile cytoskeletal linker proteins of very large size (>500 kDa) that are abundantly expressed in a wide variety of mammalian tissues and cell types. Earlier studies indicated that plectin molecules were associated with and/or directly bound to subcomponents of all three major cytoskeletal filament networks, the subplasma membrane protein skeleton, and a variety of plasma membrane-cytoskeleton junctional complexes, including those found in epithelia, various types of muscle, and fibroblasts. In conjunction with biochemical data, this led to the concept that plectin plays an important role in cytoskeleton network organization, with consequences for viscoelastic properties of the cytoplasm and the mechanical integrity and resistance of cells and tissues. Several recent findings lent strong support to this concept. One was that a hereditary disease, epidermolysis bullosa simplex (EBS)-MD, characterized by severe skin blistering combined with muscular dystrophy, is caused by defects in the plectin gene. Another was the generation of plectin-deficient mice by targeted inactivation of the gene. Dying shortly after birth, these animals exhibited severe defects in skin, skeletal muscle and heart. Moreover, in vitro studies with cells derived from such animals unmasked an essential new role of plectin as regulator of cellular processes involving actin stress fibers dynamics. Comprehensive analyses of the gene locus in man, mouse, and rat point towards a complex gene expression machinery, comprising an unprecedented diversity of differentially spliced transcripts with distinct 5' starting exons, probably regulated by different promoters. This could provide a basis for cell type-dependent and/or developmentally-controlled expression of plectin isoforms, exerting different functions through binding to distinct partners. Based on its versatile functions and structural diversification plectin emerges as a prototype cytolinker protein among a

  6. Mobile probes

    DEFF Research Database (Denmark)

    2016-01-01

    A project investigating the effectiveness of a collection of online resources for teachers' professional development used mobile probes as a data collection method. Teachers received questions and tasks on their mobile in a dialogic manner while in their everyday context as opposed to in an inter......A project investigating the effectiveness of a collection of online resources for teachers' professional development used mobile probes as a data collection method. Teachers received questions and tasks on their mobile in a dialogic manner while in their everyday context as opposed...... to in an interview. This method provided valuable insight into the contextual use, i.e. how did the online resource transfer to the work practice. However, the research team also found that mobile probes may provide the scaffolding necessary for individual and peer learning at a very local (intra-school) community...... level. This paper is an initial investigation of how the mobile probes process proved to engage teachers in their efforts to improve teaching. It also highlights some of the barriers emerging when applying mobile probes as a scaffold for learning....

  7. High-content imaging with micropatterned multiwell plates reveals influence of cell geometry and cytoskeleton on chromatin dynamics.

    Science.gov (United States)

    Harkness, Ty; McNulty, Jason D; Prestil, Ryan; Seymour, Stephanie K; Klann, Tyler; Murrell, Michael; Ashton, Randolph S; Saha, Krishanu

    2015-10-01

    Understanding the mechanisms underpinning cellular responses to microenvironmental cues requires tight control not only of the complex milieu of soluble signaling factors, extracellular matrix (ECM) connections and cell-cell contacts within cell culture, but also of the biophysics of human cells. Advances in biomaterial fabrication technologies have recently facilitated detailed examination of cellular biophysics and revealed that constraints on cell geometry arising from the cellular microenvironment influence a wide variety of human cell behaviors. Here, we create an in vitro platform capable of precise and independent control of biochemical and biophysical microenvironmental cues by adapting microcontact printing technology into the format of standard six- to 96-well plates to create MicroContact Printed Well Plates (μCP Well Plates). Automated high-content imaging of human cells seeded on μCP Well Plates revealed tight, highly consistent control of single-cell geometry, cytoskeletal organization, and nuclear elongation. Detailed subcellular imaging of the actin cytoskeleton and chromatin within live human fibroblasts on μCP Well Plates was then used to describe a new relationship between cellular geometry and chromatin dynamics. In summary, the μCP Well Plate platform is an enabling high-content screening technology for human cell biology and cellular engineering efforts that seek to identify key biochemical and biophysical cues in the cellular microenvironment.

  8. Conductivity Probe

    Science.gov (United States)

    2008-01-01

    The Thermal and Electrical Conductivity Probe (TECP) for NASA's Phoenix Mars Lander took measurements in Martian soil and in the air. The needles on the end of the instrument were inserted into the Martian soil, allowing TECP to measure the propagation of both thermal and electrical energy. TECP also measured the humidity in the surrounding air. The needles on the probe are 15 millimeters (0.6 inch) long. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  9. Visualization of endothelial actin cytoskeleton in the mouse retina.

    Directory of Open Access Journals (Sweden)

    Alessia Fraccaroli

    Full Text Available Angiogenesis requires coordinated changes in cell shape of endothelial cells (ECs, orchestrated by the actin cytoskeleton. The mechanisms that regulate this rearrangement in vivo are poorly understood - largely because of the difficulty to visualize filamentous actin (F-actin structures with sufficient resolution. Here, we use transgenic mice expressing Lifeact-EGFP to visualize F-actin in ECs. We show that in the retina, Lifeact-EGFP expression is largely restricted to ECs allowing detailed visualization of F-actin in ECs in situ. Lifeact-EGFP labels actin associated with cell-cell junctions, apical and basal membranes and highlights actin-based structures such as filopodia and stress fiber-like cytoplasmic bundles. We also show that in the skin and the skeletal muscle, Lifeact-EGFP is highly expressed in vascular mural cells (vMCs, enabling vMC imaging. In summary, our results indicate that the Lifeact-EGFP transgenic mouse in combination with the postnatal retinal angiogenic model constitutes an excellent system for vascular cell biology research. Our approach is ideally suited to address structural and mechanistic details of angiogenic processes, such as endothelial tip cell migration and fusion, EC polarization or lumen formation.

  10. Prokaryotic cells: structural organisation of the cytoskeleton and organelles

    Directory of Open Access Journals (Sweden)

    Wanderley de Souza

    2012-05-01

    Full Text Available For many years, prokaryotic cells were distinguished from eukaryotic cells based on the simplicity of their cytoplasm, in which the presence of organelles and cytoskeletal structures had not been discovered. Based on current knowledge, this review describes the complex components of the prokaryotic cell cytoskeleton, including (i tubulin homologues composed of FtsZ, BtuA, BtuB and several associated proteins, which play a fundamental role in cell division, (ii actin-like homologues, such as MreB and Mb1, which are involved in controlling cell width and cell length, and (iii intermediate filament homologues, including crescentin and CfpA, which localise on the concave side of a bacterium and along its inner curvature and associate with its membrane. Some prokaryotes exhibit specialised membrane-bound organelles in the cytoplasm, such as magnetosomes and acidocalcisomes, as well as protein complexes, such as carboxysomes. This review also examines recent data on the presence of nanotubes, which are structures that are well characterised in mammalian cells that allow direct contact and communication between cells.

  11. Prokaryotic cells: structural organisation of the cytoskeleton and organelles.

    Science.gov (United States)

    Souza, Wanderley de

    2012-05-01

    For many years, prokaryotic cells were distinguished from eukaryotic cells based on the simplicity of their cytoplasm, in which the presence of organelles and cytoskeletal structures had not been discovered. Based on current knowledge, this review describes the complex components of the prokaryotic cell cytoskeleton, including (i) tubulin homologues composed of FtsZ, BtuA, BtuB and several associated proteins, which play a fundamental role in cell division, (ii) actin-like homologues, such as MreB and Mb1, which are involved in controlling cell width and cell length, and (iii) intermediate filament homologues, including crescentin and CfpA, which localise on the concave side of a bacterium and along its inner curvature and associate with its membrane. Some prokaryotes exhibit specialised membrane-bound organelles in the cytoplasm, such as magnetosomes and acidocalcisomes, as well as protein complexes, such as carboxysomes. This review also examines recent data on the presence of nanotubes, which are structures that are well characterised in mammalian cells that allow direct contact and communication between cells.

  12. The Emerging Role of the Cytoskeleton in Chromosome Dynamics

    Directory of Open Access Journals (Sweden)

    Maya Spichal

    2017-05-01

    Full Text Available Chromosomes underlie a dynamic organization that fulfills functional roles in processes like transcription, DNA repair, nuclear envelope stability, and cell division. Chromosome dynamics depend on chromosome structure and cannot freely diffuse. Furthermore, chromosomes interact closely with their surrounding nuclear environment, which further constrains chromosome dynamics. Recently, several studies enlighten that cytoskeletal proteins regulate dynamic chromosome organization. Cytoskeletal polymers that include actin filaments, microtubules and intermediate filaments can connect to the nuclear envelope via Linker of the Nucleoskeleton and Cytoskeleton (LINC complexes and transfer forces onto chromosomes inside the nucleus. Monomers of these cytoplasmic polymers and related proteins can also enter the nucleus and play different roles in the interior of the nucleus than they do in the cytoplasm. Nuclear cytoskeletal proteins can act as chromatin remodelers alone or in complexes with other nuclear proteins. They can also act as transcription factors. Many of these mechanisms have been conserved during evolution, indicating that the cytoskeletal regulation of chromosome dynamics is an essential process. In this review, we discuss the different influences of cytoskeletal proteins on chromosome dynamics by focusing on the well-studied model organism budding yeast.

  13. Organelle trafficking, the cytoskeleton, and pollen tube growth

    Institute of Scientific and Technical Information of China (English)

    Giampiero Cai; Luigi Parrotta; Mauro Cresti

    2015-01-01

    The pol en tube is fundamental for the reproduction of seed plants. Characteristical y, it grows relatively quickly and uni‐directional y (“polarized growth”) to extend the male gametophyte to reach the female gametophyte. The pol en tube forms a channel through which the sperm cel s move so that they can reach their targets in the ovule. To grow quickly and directional y, the pol en tube requires an intense movement of organel es and vesicles that al ows the cel ’s contents to be distributed to sustain the growth rate. While the various organel es distribute more or less uniformly within the pol en tube, Golgi‐released secretory vesicles accumulate massively at the pol en tube apex, that is, the growing region. This intense movement of organel es and vesicles is dependent on the dynamics of the cytoskeleton, which reorganizes differential y in response to external signals and coordinates membrane trafficking with the growth rate of pol en tubes.

  14. The cytoskeleton significantly impacts invasive behavior of biological cells

    Science.gov (United States)

    Fritsch, Anatol; Käs, Josef; Seltman, Kristin; Magin, Thomas

    2014-03-01

    Cell migration is a key determinant of cancer metastasis and nerve regeneration. The role of the cytoskeleton for the epithelial-meschenymal transition (EMT), i.e, for invasive behavior of cells, is only partially understood. Here, we address this issue in cells lacking all keratins upon genome engineering. In contrast to prediction, keratin-free cells show a 60% higher deformability compared to less pronounced softening effects for actin depolymerization. To relate these findings with functional consequences, we use invasion and three-dimensional growth assays. These reveal higher invasiveness of keratin-free cells. This study supports the view that downregulation of keratins observed during EMT directly contributes to the migratory and invasive behavior of tumor cells. Cancer cells that effectively move through tissues are softer and more contractile than cells that stay local in tissues. Soft and contractile avoids jamming. Naturally, softness has to have its limits. So neuronal growth cones are too soft to carry large loads to move efficiently through scar tissue, which is required for nerve regeneration. In synopsis, the physical bounds that the functional modules of a moving cell experience in tissues may provide an overarching motif for novel approaches in diagnosis and therapy.

  15. Chaperonin Polymers in Archaea: The Cytoskeleton of Prokaryotes?

    Science.gov (United States)

    Trent, J. D.; Kagawa, H. K.; Zaluzec, N. J.

    1997-07-01

    Chaperonins are protein complexes that play a critical role in folding nascent polypeptides under normal conditions and refolding damaged proteins under stress conditions. In all organisms these complexes are composed of evolutionarily conserved 60-kDa proteins arranged in double-ring structures with between 7 and 9 protein subunits per ring. These double ring structures are assumed to be the functional units in vivo, although they have never been observed inside cells. Here the authors show that the purified chaperonin from the hyperthermophilic archaeon Sulfolobus shibatae, which is closely related to chaperonins in eukaryotes, has a double ring structure at low concentrations (0.1 mg/ml), but at more physiological concentrations, the rings stack end to end to form polymers. The polymers are stable at physiological temperatures (75 C) and closely resemble structures observed inside unfixed S. shibatae cells. The authors suggest that in vivo chaperonin activity may be regulated by polymerization and that chaperonin polymers may act as a cytoskeleton-like structure in archaea and bacteria.

  16. Cytoskeleton in Pollen and Pollen Tubes of Ginkgo biloba L.

    Institute of Scientific and Technical Information of China (English)

    Jun-Mei LIU; Hong ZHANG; Yan LI

    2005-01-01

    The distribution of F-actin and microtubules was investigated in pollen and pollen tubes of Ginkgo biloba L. using a confocal laser scanning microscope after fluorescence and immunofluorescence labeling. A dense F-actin network was found in hydrated Ginkgo pollen. When Ginkgo pollen was germinating,F-actin mesh was found under the plasma membrane from which the pollen tube would emerge. After pollen germination, F-actin bundles were distributed axially in long pollen tubes of G. biloba. Thick F-actin bundles and network were found in the tip of the Ginkgo pollen tube, which is opposite to the results reported for the pollen tubes of some angiosperms and conifers. In addition, a few circular F-actin bundles were found in Ginkgo pollen tubes. Using immunofluorescence labeling, a dense microtubule network was found in hydrated Ginkgo pollen under confocal microscope. In the Ginkgo pollen tube, the microtubules were distributed along the longitudinal axis and extended to the tip. These results suggest that the cytoskeleton may have an essential role in the germination of Ginkgo pollen and tube growth.

  17. Pollution Probe.

    Science.gov (United States)

    Chant, Donald A.

    This book is written as a statement of concern about pollution by members of Pollution Probe, a citizens' anti-pollution group in Canada. Its purpose is to create public awareness and pressure for the eventual solution to pollution problems. The need for effective government policies to control the population explosion, conserve natural resources,…

  18. Universal microbial diagnostics using random DNA probes

    Science.gov (United States)

    Aghazadeh, Amirali; Lin, Adam Y.; Sheikh, Mona A.; Chen, Allen L.; Atkins, Lisa M.; Johnson, Coreen L.; Petrosino, Joseph F.; Drezek, Rebekah A.; Baraniuk, Richard G.

    2016-01-01

    Early identification of pathogens is essential for limiting development of therapy-resistant pathogens and mitigating infectious disease outbreaks. Most bacterial detection schemes use target-specific probes to differentiate pathogen species, creating time and cost inefficiencies in identifying newly discovered organisms. We present a novel universal microbial diagnostics (UMD) platform to screen for microbial organisms in an infectious sample, using a small number of random DNA probes that are agnostic to the target DNA sequences. Our platform leverages the theory of sparse signal recovery (compressive sensing) to identify the composition of a microbial sample that potentially contains novel or mutant species. We validated the UMD platform in vitro using five random probes to recover 11 pathogenic bacteria. We further demonstrated in silico that UMD can be generalized to screen for common human pathogens in different taxonomy levels. UMD’s unorthodox sensing approach opens the door to more efficient and universal molecular diagnostics. PMID:27704040

  19. DBIO Best Thesis Award: Mechanics, Dynamics, and Organization of the Bacterial Cytoskeleton and Cell Wall

    Science.gov (United States)

    Wang, Siyuan

    2012-02-01

    Bacteria come in a variety of shapes. While the peptidoglycan (PG) cell wall serves as an exoskeleton that defines the static cell shape, the internal bacterial cytoskeleton mediates cell shape by recruiting PG synthesis machinery and thus defining the pattern of cell-wall synthesis. While much is known about the chemistry and biology of the cytoskeleton and cell wall, much of their biophysics, including essential aspects of the functionality, dynamics, and organization, remain unknown. This dissertation aims to elucidate the detailed biophysical mechanisms of cytoskeleton guided wall synthesis. First, I find that the bacterial cytoskeleton MreB contributes nearly as much to the rigidity of an Escherichia coli cell as the cell wall. This conclusion implies that the cytoskeletal polymer MreB applies meaningful force to the cell wall, an idea favored by theoretical modeling of wall growth, and suggests an evolutionary origin of cytoskeleton-governed cell rigidity. Second, I observe that MreB rotates around the long axis of E. coli, and the motion depends on wall synthesis. This is the first discovery of a cell-wall assembly driven molecular motor in bacteria. Third, I prove that both cell-wall synthesis and the PG network have chiral ordering, which is established by the spatial pattern of MreB. This work links the molecular structure of the cytoskeleton and of the cell wall with organismal-scale behavior. Finally, I develop a mathematical model of cytoskeleton-cell membrane interactions, which explains the preferential orientation of different cytoskeleton components in bacteria.

  20. Combined effect of cortical cytoskeleton and transmembrane proteins on domain formation in biomembranes

    DEFF Research Database (Denmark)

    Sikder, K. U.; Stone, K. A.; Kumar, P. B. S.

    2014-01-01

    We investigate the combined effects of transmembrane proteins and the subjacent cytoskeleton on the dynamics of phase separation in multicomponent lipid bilayers using computer simulations of a particle-based implicit solvent model for lipid membranes with soft-core interactions. We find that mic...... that microphase separation can be achieved by the protein confinement by the cytoskeleton. Our results have relevance to the finite size of lipid rafts in the plasma membrane of mammalian cells. (C) 2014 AIP Publishing LLC....

  1. Combined effect of cortical cytoskeleton and transmembrane proteins on domain formation in biomembranes

    Science.gov (United States)

    Sikder, Md. Kabir Uddin; Stone, Kyle A.; Kumar, P. B. Sunil; Laradji, Mohamed

    2014-08-01

    We investigate the combined effects of transmembrane proteins and the subjacent cytoskeleton on the dynamics of phase separation in multicomponent lipid bilayers using computer simulations of a particle-based implicit solvent model for lipid membranes with soft-core interactions. We find that microphase separation can be achieved by the protein confinement by the cytoskeleton. Our results have relevance to the finite size of lipid rafts in the plasma membrane of mammalian cells.

  2. Actin Cytoskeleton Manipulation by Effector Proteins Secreted by Diarrheagenic Escherichia coli Pathotypes

    Directory of Open Access Journals (Sweden)

    Fernando Navarro-Garcia

    2013-01-01

    Full Text Available The actin cytoskeleton is a dynamic structure necessary for cell and tissue organization, including the maintenance of epithelial barriers. Disruption of the epithelial barrier coincides with alterations of the actin cytoskeleton in several disease states. These disruptions primarily affect the paracellular space, which is normally regulated by tight junctions. Thereby, the actin cytoskeleton is a common and recurring target of bacterial virulence factors. In order to manipulate the actin cytoskeleton, bacteria secrete and inject toxins and effectors to hijack the host cell machinery, which interferes with host-cell pathways and with a number of actin binding proteins. An interesting model to study actin manipulation by bacterial effectors is Escherichia coli since due to its genome plasticity it has acquired diverse genetic mobile elements, which allow having different E. coli varieties in one bacterial species. These E. coli pathotypes, including intracellular and extracellular bacteria, interact with epithelial cells, and their interactions depend on a specific combination of virulence factors. In this paper we focus on E. coli effectors that mimic host cell proteins to manipulate the actin cytoskeleton. The study of bacterial effector-cytoskeleton interaction will contribute not only to the comprehension of the molecular causes of infectious diseases but also to increase our knowledge of cell biology.

  3. Product Platform Performance

    DEFF Research Database (Denmark)

    Munk, Lone

    engaging in platform-based product development. Similarly platform assessment criteria lack empirical verification regarding relevance and sufficiency. The thesis focuses on • the process of identifying and estimating internal effects, • verification of performance of product platforms, (i...... to support this understanding. Finally a categorisation of different approaches to platform-based product development is introduced, based on the companies from the industrial study.......The aim of this research is to improve understanding of platform-based product development by studying platform performance in relation to internal effects in companies. Platform-based product development makes it possible to deliver product variety and at the same time reduce the needed resources...

  4. Micro scanning probes

    CERN Document Server

    Niblock, T

    2001-01-01

    This thesis covers the design methodology, theory, modelling, fabrication and evaluation of a Micro-Scanning-Probe. The device is a thermally actuated bimorph quadrapod fabricated using Micro Electro Mechanical Systems technology. A quadrapod is a structure with four arms, in this case a planar structure with the four arms forming a cross which is dry etched out of a silicon diaphragm. Each arm has a layer of aluminium deposited on it forming a bimorph. Through heating each arm actuation is achieved in the plane of the quadrapod and the direction normal to it. Fabrication of the device has required the development of bulk micromachining techniques to handle post CMOS fabricated wafers and the patterning of thickly sputtered aluminium in bulk micro machined cavities. CMOS fabrication techniques were used to incorporate diodes onto the quadrapod arms for temperature measurement of the arms. Fine tungsten and silicon tips have also been fabricated to allow tunnelling between the tip and the platform at the centr...

  5. Product Platform Modeling

    DEFF Research Database (Denmark)

    Pedersen, Rasmus

    on the notion that reuse and encapsulation of platform elements are fundamental characteristics of a product platform. Reuse covers the desire to reuse and share certain assets across a family of products and/or across generations of products. Product design solutions and principles are often regarded...... as important assets in a product platform, yet activities, working patterns, processes and knowledge can also be reused in a platform approach. Encapsulation is seen as a process in which the different elements of a platform are grouped into well defined and self-contained units which are decoupled from each......This PhD thesis has the title Product Platform Modelling. The thesis is about product platforms and visual product platform modelling. Product platforms have gained an increasing attention in industry and academia in the past decade. The reasons are many, yet the increasing globalisation...

  6. The actin cytoskeleton may control the polar distribution of an auxin transport protein

    Science.gov (United States)

    Muday, G. K.; Hu, S.; Brady, S. R.; Davies, E. (Principal Investigator)

    2000-01-01

    The gravitropic bending of plants has long been linked to the changes in the transport of the plant hormone auxin. To understand the mechanism by which gravity alters auxin movement, it is critical to know how polar auxin transport is initially established. In shoots, polar auxin transport is basipetal (i.e., from the shoot apex toward the base). It is driven by the basal localization of the auxin efflux carrier complex. One mechanism for localizing this efflux carrier complex to the basal membrane may be through attachment to the actin cytoskeleton. The efflux carrier protein complex is believed to consist of several polypeptides, including a regulatory subunit that binds auxin transport inhibitors, such as naphthylphthalamic acid (NPA). Several lines of experimentation have been used to determine if the NPA binding protein interacts with actin filaments. The NPA binding protein has been shown to partition with the actin cytoskeleton during detergent extraction. Agents that specifically alter the polymerization state of the actin cytoskeleton change the amount of NPA binding protein and actin recovered in these cytoskeletal pellets. Actin-affinity columns were prepared with polymers of actin purified from zucchini hypocotyl tissue. NPA binding activity was eluted in a single peak from the actin filament column. Cytochalasin D, which fragments the actin cytoskeleton, was shown to reduce polar auxin transport in zucchini hypocotyls. The interaction of the NPA binding protein with the actin cytoskeleton may localize it in one plane of the plasma membrane, and thereby control the polarity of auxin transport.

  7. A double signal electrochemical human immunoglobulin G immunosensor based on gold nanoparticles-polydopamine functionalized reduced graphene oxide as a sensor platform and AgNPs/carbon nanocomposite as signal probe and catalytic substrate.

    Science.gov (United States)

    Zhang, Si; Huang, Na; Lu, Qiujun; Liu, Meiling; Li, Haitao; Zhang, Youyu; Yao, Shouzhuo

    2016-03-15

    In this paper, a double signal electrochemical Human immunoglobulin G (HIgG) immunosensor based on AgNPs/carbon nanocomposite (Ag/C NC) as the signal probe and catalytic substrate was developed for fast and sensitive detection of HIgG. The as-prepared AuNPs-PDA-rGO nanocomposite and Ag/C NC were confirmed by UV-vis, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. Electrochemical impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical properties of the proposed immunosensor. The AuNPs-PDA-rGO nanocomposite can improve the electron transfer rate and capture more Ab1. In the sandwich-type immunoassay process, the Ag/C NC functionalized bioconjugates were captured on HIgG/Ab1/AuNPs-PDA-rGO surface and the electrochemical double-signal strategy was employed. These double electrochemical detection signals were directly monitored the oxidation current originated from Ag/C NC and indirectly detected the reduction current of benzoquinone which was produced from the reaction of H2O2 and HQ by catalysis of Ag/C NC in electrochemical detection of HIgG. Under the optimized conditions, the current responses were changed with the concentrations of HIgG for the proposed immunosensor with wide linear ranges of 0.1 to 100 ngmL(-1) and 0.01-100 ngmL(-1) with the lowest detection concentration of 0.001 ng mL(-1) in the absence and presence of H2O2 and HQ. The double-signal strategy is used for detection of HIgG, and the results came from the two signals were well consistent with each other. The proposed immunosensor was successfully applied in analysis of human IgG in real samples and this strategy may provide a relative simple and effective method for construction of other immunsensors in detection of other biomarkers in clinical medicine.

  8. Visualizing the actin cytoskeleton in living plant cells using a photo-convertible mEos::FABD-mTn fluorescent fusion protein

    Directory of Open Access Journals (Sweden)

    Bewley J Derek

    2008-09-01

    Full Text Available Abstract Background The actin cytoskeleton responds quickly to diverse stimuli and plays numerous roles in cellular signalling, organelle motility and subcellular compartmentation during plant growth and development. Molecular and cell biological tools that can facilitate visualization of actin organization and dynamics in a minimally invasive manner are essential for understanding this fundamental component of the living cell. Results A novel, monomeric (m Eos-fluorescent protein derived from the coral Lobophyllia hemprichii was assessed for its green to red photo-convertibility in plant cells by creating mEosFP-cytosolic. mEosFP was fused to the F-(filamentous-Actin Binding Domain of the mammalian Talin gene to create mEosFP::FABDmTalin. Photo-conversion, visualization and colour quantification protocols were developed for EosFP targeted to the F-actin cytoskeleton. Rapid photo-conversion in the entire cell or in a region of interest was easily achieved upon illumination with an approximately 400 nm wavelength light beam using an epi-fluorescent microscope. Dual color imaging after photo-conversion was carried out using a confocal laser-scanning microscope. Time-lapse imaging revealed that although photo-conversion of single mEosFP molecules can be rapid in terms of live-cell imaging it involves a progressive enrichment of red fluorescent molecules over green species. The fluorescence of photo-converted cells thus progresses through intermediate shades ranging from green to red. The time taken for complete conversion to red fluorescence depends on protein expression level within a cell and the quality of the focusing lens used to deliver the illuminating beam. Three easily applicable methods for obtaining information on fluorescent intensity and colour are provided as a means of ensuring experimental repeatability and data quantification, when using mEosFP and similar photo-convertible proteins. Conclusion The mEosFP::FABD-mTn probe retains

  9. ITS Platform North Denmark

    DEFF Research Database (Denmark)

    Lahrmann, Harry; Agerholm, Niels; Juhl, Jens

    2012-01-01

    This paper presents the project entitled “ITS Platform North Denmark” which is used as a test platform for Intelligent Transportation System (ITS) solutions. The platform consists of a newly developed GNSS/GPRS On Board Unit (OBU) to be installed in 500 cars, a backend server and a specially...... designed digital road map for ITS applications. The platform is freely accessible, which means that third party applications could be run on the platform. It is estimated that using this platform enables the ITS applications to be developed for 20% of the normal cost, hence third party are invited to test...... their applications in this platform. This paper presents the platform’s potentials and explains a series of test applications which are under development on it. Moreover, a number of new projects planned for the platform are demonstrated....

  10. Mobile platform security

    CERN Document Server

    Asokan, N; Dmitrienko, Alexandra

    2013-01-01

    Recently, mobile security has garnered considerable interest in both the research community and industry due to the popularity of smartphones. The current smartphone platforms are open systems that allow application development, also for malicious parties. To protect the mobile device, its user, and other mobile ecosystem stakeholders such as network operators, application execution is controlled by a platform security architecture. This book explores how such mobile platform security architectures work. We present a generic model for mobile platform security architectures: the model illustrat

  11. Acoustic tweezing cytometry for live-cell subcellular modulation of intracellular cytoskeleton contractility

    Science.gov (United States)

    Fan, Zhenzhen; Sun, Yubing; di Chen; Tay, Donald; Chen, Weiqiang; Deng, Cheri X.; Fu, Jianping

    2013-07-01

    Mechanical forces are critical to modulate cell spreading, contractility, gene expression, and even stem cell differentiation. Yet, existing tools that can apply controllable subcellular forces to a large number of single cells simultaneously are still limited. Here we report a novel ultrasound tweezing cytometry utilizing ultrasound pulses to actuate functionalized lipid microbubbles covalently attached to single live cells to exert mechanical forces in the pN - nN range. Ultrasonic excitation of microbubbles could elicit a rapid and sustained reactive intracellular cytoskeleton contractile force increase in different adherent mechanosensitive cells. Further, ultrasound-mediated intracellular cytoskeleton contractility enhancement was dose-dependent and required an intact actin cytoskeleton as well as RhoA/ROCK signaling. Our results demonstrated the great potential of ultrasound tweezing cytometry technique using functionalized microbubbles as an actuatable, biocompatible, and multifunctional agent for biomechanical stimulations of cells.

  12. Removal of the mechanoprotective influence of the cytoskeleton reveals PIEZO1 is gated by bilayer tension

    Science.gov (United States)

    Cox, Charles D.; Bae, Chilman; Ziegler, Lynn; Hartley, Silas; Nikolova-Krstevski, Vesna; Rohde, Paul R.; Ng, Chai-Ann; Sachs, Frederick; Gottlieb, Philip A.; Martinac, Boris

    2016-01-01

    Mechanosensitive ion channels are force-transducing enzymes that couple mechanical stimuli to ion flux. Understanding the gating mechanism of mechanosensitive channels is challenging because the stimulus seen by the channel reflects forces shared between the membrane, cytoskeleton and extracellular matrix. Here we examine whether the mechanosensitive channel PIEZO1 is activated by force-transmission through the bilayer. To achieve this, we generate HEK293 cell membrane blebs largely free of cytoskeleton. Using the bacterial channel MscL, we calibrate the bilayer tension demonstrating that activation of MscL in blebs is identical to that in reconstituted bilayers. Utilizing a novel PIEZO1-GFP fusion, we then show PIEZO1 is activated by bilayer tension in bleb membranes, gating at lower pressures indicative of removal of the cortical cytoskeleton and the mechanoprotection it provides. Thus, PIEZO1 channels must sense force directly transmitted through the bilayer.

  13. Profilin as a regulator of the membrane-actin cytoskeleton interface in plant cells

    Directory of Open Access Journals (Sweden)

    Tiantian eSun

    2013-12-01

    Full Text Available Membrane structures and cytoskeleton dynamics are intimately inter-connected in the eukaryotic cell. Recently, the molecular mechanisms operating at this interface have been progressively addressed. Many experiments have revealed that the actin cytoskeleton can interact with membranes through various discrete membrane domains. The actin-binding protein, profilin has been proven to inhibit actin polymerization and to promote F-actin elongation. This is dependent on many factors, such as the profilin/G-actin ratio and the ionic environment of the cell. Additionally, profilin has specific domains that interact with phosphoinositides and poly-L-proline rich proteins; theoretically, this gives profilin the opportunity to interact with membranes, and a large number of experiments have confirmed this possibility. In this article, we summarize recent findings in plant cells, and discuss the evidence of the connections among actin cytoskeleton, profilin and biomembranes through direct or indirect relationships.

  14. Change in the actin cytoskeleton during seismonastic movement of Mimosa pudica.

    Science.gov (United States)

    Kanzawa, Nobuyuki; Hoshino, Yoshinori; Chiba, Makiko; Hoshino, Daisuke; Kobayashi, Hidetaka; Kamasawa, Naomi; Kishi, Yoshiro; Osumi, Masako; Sameshima, Masazumi; Tsuchiya, Takahide

    2006-04-01

    The seismonastic movement of Mimosa pudica is triggered by a sudden loss of turgor pressure. In the present study, we compared the cell cytoskeleton by immunofluorescence analysis before and after movement, and the effects of actin- and microtubule-targeted drugs were examined by injecting them into the cut pulvinus. We found that fragmentation of actin filaments and microtubules occurs during bending, although the actin cytoskeleton, but not the microtubules, was involved in regulation of the movement. Transmission electron microscopy revealed that actin cables became loose after the bending. We injected phosphatase inhibitors into the severed pulvinus to examine the effects of such inhibitors on the actin cytoskeleton. We found that changes in actin isoforms, fragmentation of actin filaments and the bending movement were all inhibited after injection of a tyrosine phosphatase inhibitor. We thus propose that the phosphorylation status of actin at tyrosine residues affects the dynamic reorganization of actin filaments and causes seismonastic movement.

  15. Cytoskeleton, L-type Ca2+ and stretch activated channels in injured skeletal muscle

    Directory of Open Access Journals (Sweden)

    Fabio Francini

    2013-07-01

    Full Text Available The extra-sarcomeric cytoskeleton (actin microfilaments and anchoring proteins is involved in maintaining the sarco-membrane stiffness and integrity and in turn the mechanical stability and function of the intra- and sub-sarcoplasmic proteins. Accordingly, it regulates Ca2+ entry through the L-type Ca2+ channels and the mechano-sensitivity of the stretch activated channels (SACs. Moreover, being intra-sarcomeric cytoskeleton bound to costameric proteins and other proteins of the sarcoplasma by intermediate filaments, as desmin, it integrates the properties of the sarcolemma with the skeletal muscle fibres contraction. The aim of this research was to compare the cytoskeleton, SACs and the ECC alterations in two different types of injured skeletal muscle fibres: by muscle denervation and mechanical overload (eccentric contraction. Experiments on denervation were made in isolated Soleus muscle of male Wistar rats; forced eccentric-contraction (EC injury was achieved in Extensor Digitorum Longus muscles of Swiss mice. The method employed conventional intracellular recording with microelectrodes inserted in a single fibre of an isolated skeletal muscle bundle. The state of cytoskeleton was evaluated by recording SAC currents and by evaluating the resting membrane potential (RMP value determined in current-clamp mode. The results demonstrated that in both injured skeletal muscle conditions the functionality of L-type Ca2+ current, ICa, was affected. In parallel, muscle fibres showed an increase of the resting membrane permeability and of the SAC current. These issues, together with a more depolarized RMP are an index of altered cytoskeleton. In conclusion, we found a symilar alteration of ICa, SAC and cytoskeleton in both injured skeletal muscle conditions.

  16. Reorganization of the subplasmalemmal cytoskeleton in association with exocytosis in rat mast cells

    DEFF Research Database (Denmark)

    Nielsen, E H; Braun, K; Johansen, Torben

    1989-01-01

    The subplasmalemmal cytoskeleton in mast cells has been studied by scanning electron microscopy of the internal side of the plasma membrane. Rearrangement of the dense subplasmalemmal network of actin filaments took place following cell activation by compound 48/80 and secretion of histamine....... The rearrangement was a withdrawal of the subplasmalemmal cytoskeleton from the exocytotic sites and the development of bare, filament-free areas around the sites. In calcium-depleted mast cells we demonstrated a dense network that was difficult to break. Activation of the calcium-depleted cells by compound 48...

  17. Heparan sulfate proteoglycans of rat embryo fibroblasts. A hydrophobic form may link cytoskeleton and matrix components

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R; Höök, M

    1985-01-01

    as HSPG. However, the majority of radiolabeled proteoglycans isolated from the cell layer were HSPGs. Here, two types of HSPG were detected. One type had an Mr of 5-8 X 10(5) as estimated by gel chromatography on Sepharose CL-4B in the presence of 0.1% sodium dodecyl sulfate and lacked hydrophobic...... extraction of the cell contained the larger species of HSPG in addition to the smaller HSPG. The presence of the smaller hydrophobic HSPG in the detergent-treated cytoskeleton-matrix preparations suggests that it may form part of a transmembrane cytoskeleton-matrix linkage....

  18. Continuous Platform Development

    DEFF Research Database (Denmark)

    Nielsen, Ole Fiil

    low risks and investments but also with relatively fuzzy results. When looking for new platform projects, it is important to make sure that the company and market is ready for the introduction of platforms, and to make sure that people from marketing and sales, product development, and downstream......, but continuous product family evolution challenges this strategy. The concept of continuous platform development is based on the fact that platform development should not be a one-time experience but rather an ongoing process of developing new platforms and updating existing ones, so that product family...

  19. Cross-Platform Technologies

    Directory of Open Access Journals (Sweden)

    Maria Cristina ENACHE

    2017-04-01

    Full Text Available Cross-platform - a concept becoming increasingly used in recent years especially in the development of mobile apps, but this consistently over time and in the development of conventional desktop applications. The notion of cross-platform software (multi-platform or platform-independent refers to a software application that can run on more than one operating system or computing architecture. Thus, a cross-platform application can operate independent of software or hardware platform on which it is execute. As a generic definition presents a wide range of meanings for purposes of this paper we individualize this definition as follows: we will reduce the horizon of meaning and we use functionally following definition: a cross-platform application is a software application that can run on more than one operating system (desktop or mobile identical or in a similar way.

  20. INTERNAL CORROSION MONITORING IN OFFSHORE PLATFORMS

    Directory of Open Access Journals (Sweden)

    Fernando Benedicto Mainier

    2008-08-01

    Full Text Available Corrosion is one of the main causes of failures in equipment and pipes in off-shore oil production. These failures harm the process, slow the production operational chronogram, and generate high costs of maintenance, beyond generation risks to health and environment. Due to the fact that most of the equipment, tubing and pipes of production platforms are made of steel, in general, carbon steel, the industry of petroleum exploration will always coexist with the corrosive process. The use of a Corrosion Monitoring Plan to diagnostic, to control and to manage the evolution of corrosives process in off-shore oil platforms is the strategy proposed in this work to prevent problems as described above. The Internal Corrosion Monitoring Plan (ICMP, is based on lab analysis of the corrosively of fluids and residues showed periodically in off-shore operational platform; in the corrosion rate determined by the periodic use of test bodies installed inside off-shore oil platforms tubing systems, as mass loss coupons and electric resistance probes; and finally, in periodic operational data collect obtained during the off-shore oil platform systems operation. The ICMP will direct and manage the actions to be taken in case of aggravation of a corrosive process, quickly identifying to the corrosive mechanisms and its localization in the various systems of the platforms. The optimized use of the corrosion inhibitor and other chemical products are one of the main advantages of the ICMP.

  1. Localization of Vibrio vulnificus infection in dendritic cells and its effects on the cytoskeleton

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi-gang; XU Shui-ling; SHAO Ping-yang; BAO Yi; CUI Ge; CAI Yu-jie

    2012-01-01

    Background Vibrio vulnificus (Vv) is an estuarine bacterium that can cause primary septicemia as well as serious wound infections.However,little is known about the mechanisms by which Vv infects dendritic cells (DCs) and its effects on cytoskeleton.In this study,we aimed to investigate the invasion,internalization,and the organelles damage of the cultured dendritic cells (a DC 2.4 strain) during Vv infection.Methods The study model was the cultured DCs infected by a Vv 1.758 strain.Electron microscopy was used to observe the localization of bacteria at the different time points of infection,cell morphology,and the process of organelles changes.The cytoskeleton structure including the microfilaments and the microtubules rearrangement was examined under a fluorescence microscope.Results The Vv were pinocytosised into the DC cells through double-sides,and localized at 1-2 μm of the inner side membrane.It took 1.3,1.9,and 3.4 hours to reach the infection ratio of 25%,50%,and 75%,respectively.Using electron microscopy,the DCs had been observed to have developed chromatin aggregation within 4.0 hours,and significant cytoskeleton structure disruption was noted within 6.0 hours.Conclusion The high lethality of Vv infection may be associated with the direct disruption of the DCs cytoskeleton structure.

  2. Association of EGF and LDL receptors with the cytoskeleton of cultured keratinocytes

    NARCIS (Netherlands)

    Pas, M.F.W. te; Ponec, M.; Bergen Henegouwen, P.M.P. van; Lombardi, P.; Havekes, L.M.; Boonstra, J.

    1990-01-01

    In this paper we demonstrate that isolated cytoskeletons of normal keratinocytes cultured under differentiation inducing conditions exhibit a high level of epidermal growth factor (EGF) binding. This binding is approximately 300% higher than the binding of intact cells. In contrast, various squamous

  3. Temperature response of the neuronal cytoskeleton mapped via atomic force and fluorescence microscopy

    Science.gov (United States)

    Spedden, Elise; Kaplan, David L.; Staii, Cristian

    2013-10-01

    Neuronal cells change their growth properties in response to external physical stimuli such as variations in external temperature, stiffness of the growth substrate, or topographical guidance cues. Detailed knowledge of the mechanisms that control these biomechanical responses is necessary for understanding the basic principles that underlie neuronal growth and regeneration. Here, we present elasticity maps of living cortical neurons (embryonic rat) as a function of temperature, and correlate these maps to the locations of internal structural components of the cytoskeleton. Neurons display a significant increase in the average elastic modulus upon a decrease in ambient temperature from 37 to 25 °C. We demonstrate that the dominant mechanism by which the elasticity of the neurons changes in response to temperature is the stiffening of the actin components of the cytoskeleton induced by myosin II. We also report a reversible shift in the location and composition of the high-stiffness areas of the neuron cytoskeleton with temperature. At 37 °C the areas of the cell displaying high elastic modulus overlap with the tubulin-dense regions, while at 25 °C these high-stiffness areas correspond to the actin-dense regions of the cytoskeleton. These results demonstrate the importance of considering temperature effects when investigating cytoskeletal dynamics in cells.

  4. Platform switching and bone platform switching.

    Science.gov (United States)

    Carinci, Francesco; Brunelli, Giorgio; Danza, Matteo

    2009-01-01

    Bone platform switching involves an inward bone ring in the coronal part of the implant that is in continuity with the alveolar bone crest. Bone platform switching is obtained by using a dental fixture with a reverse conical neck. A retrospective study was performed to evaluate the effectiveness of conventional vs reverse conical neck implants. In the period between May 2004 and November 2007, 86 patients (55 females and 31 males; median age, 53 years) were operated and 234 implants were inserted: 40 and 194 were conventional vs reverse conical neck implants, respectively. Kaplan-Meier algorithm and Cox regression were used to detect those variables associated with the clinical outcome. No differences in survival and success rates were detected between conventional vs reverse conical neck implants alone or in combination with any of the studied variables. Although bone platform switching leads to several advantages, no statistical difference in alveolar crest resorption is detected in comparison with reverse conical neck implants. We suppose that the proximity of the implant abutment junction to the alveolar crestal bone gives no protection against the microflora contained in the micrograph. Additional studies on larger series and a combination of platform switching and bone platform switching could lead to improved clinical outcomes.

  5. Platform development supportedby gaming

    DEFF Research Database (Denmark)

    Mikkola, Juliana Hsuan; Hansen, Poul H. Kyvsgård

    2007-01-01

    The challenge of implementing industrial platforms in practice can be described as a configuration problem caused by high number of variables, which often have contradictory influences on the total performance of the firm. Consequently, the specific platform decisions become extremely complex......, possibly increasing the strategic risks for the firm. This paper reports preliminary findings on platform management process at LEGO, a Danish toy company.  Specifically, we report the process of applying games combined with simulations and workshops in the platform development. We also propose a framework......, based on the portfolio management thinking, to measure the degree of modularity embedded in a given platform and to what extent it is aligned with other platforms....

  6. Effects of latrunculin B on the actin cytoskeleton and hyphal growth in Phytophthora infestans.

    Science.gov (United States)

    Ketelaar, Tijs; Meijer, Harold J G; Spiekerman, Marjolein; Weide, Rob; Govers, Francine

    2012-12-01

    The actin cytoskeleton is conserved in all eukaryotes, but its functions vary among different organisms. In oomycetes, the function of the actin cytoskeleton has received relatively little attention. We have performed a bioinformatics study and show that oomycete actin genes fall within a distinct clade that is divergent from plant, fungal and vertebrate actin genes. To obtain a better understanding of the functions of the actin cytoskeleton in hyphal growth of oomycetes, we studied the actin organization in Phytophthora infestans hyphae and the consequences of treatment with the actin depolymerising drug latrunculin B (latB). This revealed that latB treatment causes a concentration dependent inhibition of colony expansion and aberrant hyphal growth. The most obvious aberrations observed upon treatment with 0.1 μM latB were increased hyphal branching and irregular tube diameters whereas at higher concentrations latB (0.5 and 1 μM) tips of expanding hyphae changed into balloon-like shapes. This aberrant growth correlated with changes in the organization of the actin cytoskeleton. In untreated hyphae, staining with fluorescently tagged phalloidin revealed two populations of actin filaments: long, axially oriented actin filament cables and cortical actin filament plaques. Two hyphal subtypes were recognized, one containing only plaques and the other containing both cables and plaques. In the latter, some hyphae had an apical zone without actin filament plaques. Upon latB treatment, the proportion of hyphae without actin filament cables increased and there were more hyphae with a short apical zone without actin filament plaques. In general, actin filament plaques were more resilient against actin depolymerisation than actin filament cables. Besides disturbing hyphal growth and actin organization, actin depolymerisation also affected the positioning of nuclei. In the presence of latB, the distance between nuclei and the hyphal tip decreased, suggesting that the actin

  7. The Drosophila Anion Exchanger (DAE lacks a detectable interaction with the spectrin cytoskeleton

    Directory of Open Access Journals (Sweden)

    Base Christine

    2010-06-01

    Full Text Available Abstract Background Current models suggest that the spectrin cytoskeleton stabilizes interacting ion transport proteins at the plasma membrane. The human erythrocyte anion exchanger (AE1 was the first membrane transport protein found to be associated with the spectrin cytoskeleton. Here we evaluated a conserved anion exchanger from Drosophila (DAE as a marker for studies of the downstream effects of spectrin cytoskeleton mutations. Results Sequence comparisons established that DAE belongs to the SLC4A1-3 subfamily of anion exchangers that includes human AE1. Striking sequence conservation was observed in the C-terminal membrane transport domain and parts of the N-terminal cytoplasmic domain, but not in the proposed ankyrin-binding site. Using an antibody raised against DAE and a recombinant transgene expressed in Drosophila S2 cells DAE was shown to be a 136 kd plasma membrane protein. A major site of expression was found in the stomach acid-secreting region of the larval midgut. DAE codistributed with an infolded subcompartment of the basal plasma membrane of interstitial cells. However, spectrin did not codistribute with DAE at this site or in anterior midgut cells that abundantly expressed both spectrin and DAE. Ubiquitous knockdown of DAE with dsRNA eliminated antibody staining and was lethal, indicating that DAE is an essential gene product in Drosophila. Conclusions Based on the lack of colocalization and the lack of sequence conservation at the ankyrin-binding site, it appears that the well-characterized interaction between AE1 and the spectrin cytoskeleton in erythrocytes is not conserved in Drosophila. The results establish a pattern in which most of the known interactions between the spectrin cytoskeleton and the plasma membrane in mammals do not appear to be conserved in Drosophila.

  8. An actin cytoskeleton with evolutionarily conserved functions in the absence of canonical actin-binding proteins.

    Science.gov (United States)

    Paredez, Alexander R; Assaf, Zoe June; Sept, David; Timofejeva, Ljudmilla; Dawson, Scott C; Wang, Chung-Ju Rachel; Cande, W Z

    2011-04-12

    Giardia intestinalis, a human intestinal parasite and member of what is perhaps the earliest-diverging eukaryotic lineage, contains the most divergent eukaryotic actin identified to date and is the first eukaryote known to lack all canonical actin-binding proteins (ABPs). We sought to investigate the properties and functions of the actin cytoskeleton in Giardia to determine whether Giardia actin (giActin) has reduced or conserved roles in core cellular processes. In vitro polymerization of giActin produced filaments, indicating that this divergent actin is a true filament-forming actin. We generated an anti-giActin antibody to localize giActin throughout the cell cycle. GiActin localized to the cortex, nuclei, internal axonemes, and formed C-shaped filaments along the anterior of the cell and a flagella-bundling helix. These structures were regulated with the cell cycle and in encysting cells giActin was recruited to the Golgi-like cyst wall processing vesicles. Knockdown of giActin demonstrated that giActin functions in cell morphogenesis, membrane trafficking, and cytokinesis. Additionally, Giardia contains a single G protein, giRac, which affects the Giardia actin cytoskeleton independently of known target ABPs. These results imply that there exist ancestral and perhaps conserved roles for actin in core cellular processes that are independent of canonical ABPs. Of medical significance, the divergent giActin cytoskeleton is essential and commonly used actin-disrupting drugs do not depolymerize giActin structures. Therefore, the giActin cytoskeleton is a promising drug target for treating giardiasis, as we predict drugs that interfere with the Giardia actin cytoskeleton will not affect the mammalian host.

  9. Modulating the actin cytoskeleton affects mechanically induced signal transduction and differentiation in mesenchymal stem cells.

    Directory of Open Access Journals (Sweden)

    Petra Müller

    Full Text Available Mechanical interactions of mesenchymal stem cells (MSC with the environment play a significant role in controlling the diverse biological functions of these cells. Mechanical forces are transduced by integrins to the actin cytoskeleton that functions as a scaffold to switch mechanical signals into biochemical pathways. To explore the significance of cytoskeletal mechanisms in human MSC we modulated the actin cytoskeleton using the depolymerising drugs cytochalasin D (CytD and latrunculin A (LatA, as well as the stabilizing drug jasplakinolide (Jasp and examined the activation of the signalling molecules ERK and AKT during mechanical loading. All three drugs provoked significant changes in cell morphology and organisation of the cytoskeleton. Application of mechanical forces to β1-integrin receptors using magnetic beads without deformation of the cell shape induced a phosphorylation of ERK and AKT. Of the two drugs that inhibited the cytoskeletal polymerization, LatA completely blocked the activation of ERK and AKT due to mechanical forces, whereas CytD inhibited the activation of AKT but not of ERK. Activation of both signalling molecules by integrin loading was not affected due to cell treatment with the cytoskeleton stabilizing drug Jasp. To correlate the effects of the drugs on mechanically induced activation of AKT and ERK with parameters of MSC differentiation, we studied ALP activity as a marker for osteogenic differentiation and examined the uptake of fat droplets as marker for adipogenic differentiation in the presence of the drugs. All three drugs inhibited ALP activity of MSC in osteogenic differentiation medium. Adipogenic differentiation was enhanced by CytD and Jasp, but not by LatA. The results indicate that modulation of the cytoskeleton using perturbing drugs can differentially modify both mechanically induced signal transduction and MSC differentiation. In addition to activation of the signalling molecules ERK and AKT, other

  10. High aspect ratio silicon nanowires control fibroblast adhesion and cytoskeleton organization.

    Science.gov (United States)

    Andolfi, Laura; Murello, Anna; Cassese, Damiano; Ban, Jelena; Dal Zilio, Simone; Lazzarino, Marco

    2017-04-18

    Cell-cell and cell-matrix interactions are essential to the survival and proliferation of most cells, and are responsible for triggering a wide range of biochemical pathways. More recently, the biomechanical role of those interactions was highlighted, showing, for instance, that adhesion forces are essential for cytoskeleton organization. Silicon nanowires (Si NWs) with their small size, high aspect ratio and anisotropic mechanical response represent a useful model to investigate the forces involved in the adhesion processes and their role in cellular development. In this work we explored and quantified, by single cell force spectroscopy (SCFS), the interaction of mouse embryonic fibroblasts with a flexible forest of Si NWs. We observed that the cell adhesion forces are comparable to those found on collagen and bare glass coverslip, analogously the membrane tether extraction forces are similar to that on collagen but stronger than that on bare flat glass. Cell survival did not depend significantly on the substrate, although a reduced proliferation after 36 h was observed. On the contrary both cell morphology and cytoskeleton organization revealed striking differences. The cell morphology on Si-NW was characterized by a large number of filopodia and a significant decrease of the cell mobility. The cytoskeleton organization was characterized by the absence of actin fibers, which were instead dominant on collagen and flat glass support. Such findings suggest that the mechanical properties of disordered Si NWs, and in particular their strong asymmetry, play a major role in the adhesion, morphology and cytoskeleton organization processes. Indeed, while adhesion measurements by SCFS provide out-of-plane forces values consistent with those measured on conventional substrates, weaker in-plane forces hinder proper cytoskeleton organization and migration processes.

  11. Proximal Probes Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Proximal Probes Facility consists of laboratories for microscopy, spectroscopy, and probing of nanostructured materials and their functional properties. At the...

  12. DFH-3 Satellite Platform

    Institute of Scientific and Technical Information of China (English)

    RenShufang

    2005-01-01

    The DFH-3 satellite platform is designed and developed by China Academy of Space Technology (CAST). It is a medium capability communications satellite platform. The platform adopts threeaxis attitude stabilization control system, having solar array output power of 1.7kW by the end of its design lifetime of 8 years. Its mass is 2100kg with payload capacity of 220kg.

  13. Product Platform Replacements

    DEFF Research Database (Denmark)

    Sköld, Martin; Karlsson, Christer

    2012-01-01

    Purpose – It is argued in this article that too little is known about product platforms and how to deal with them from a manager's point of view. Specifically, little information exists regarding when old established platforms are replaced by new generations in R&D and production environments...... originality and value is achieved by focusing on product platform replacements believed to represent a growing management challenge....

  14. The Creative Platform

    DEFF Research Database (Denmark)

    Byrge, Christian; Hansen, Søren

    This book is about introducing more creativity into general educational courses and cross-disciplinary activities. It is directed toward teachers at all levels in the educational system, but the Creative Platform is a general model, and thus the creative process will fundamentally be the same...... whether you consider thirdgrade teaching, human-resource development, or radical new thinking in product development in a company. The Creative Platform was developed at Aalborg University through a series of research-and-development activities in collaboration with educational institutions and private...... you can use in your work with the Creative Platform. This book is intended as an introduction on how to use the Creative Platform....

  15. Omnidirectional holonomic platforms

    Energy Technology Data Exchange (ETDEWEB)

    Pin, F.G.; Killough, S.M.

    1994-06-01

    This paper presents the concepts for a new family of wheeled platforms which feature full omnidirectionality with simultaneous and independently controlled rotational and translational motion capabilities. The authors first present the orthogonal-wheels concept and the two major wheel assemblies on which these platforms are based. They then describe how a combination of these assemblies with appropriate control can be used to generate an omnidirectional capability for mobile robot platforms. The design and control of two prototype platforms are then presented and their respective characteristics with respect to rotational and translational motion control are discussed.

  16. Advanced offshore oil platforms

    Energy Technology Data Exchange (ETDEWEB)

    Ellers, F.S.

    1982-04-01

    Four innovative offshore platforms that are designed to withstand 100-foot waves in waters 600-feet deep are described. These platforms are: (1) Stratfjord B Concrete Gravity-Base Platform; (2) Magnus Steel-Template-Jacket Platform; (3) Hutton Tension-Leg Platform; and (4) Block 280 Guyed Tower. The Statfjord B platform, designed in Norway, rests on four massive concrete columns with storage tanks at the base. It depends solely on its own mass for stability. The Magnus platform, designed by the British, is the heaviest offshore platform yet fabricated, weighing 41,000 tons. Two of the platform's four legs will incorporate flotation chambers so that the structure can be floated to its site in the North Sea. The Hutton structure, also designed in England, will consist of a buoyant hull tethered to the sea floor by slender steel tubes at its four corners. The first platform of its type, the Hutton structure is also destined for the North Sea. The US designed Block 280 guyed tower is designed for service in the Gulf of Mexico in water 1000 feet deep. It will be pinned to the sea floor by a spokelike array of 20 steel cables, each one more than 3000 feet long. The tower and its guys will weigh 43,000 tons, slightly more than the Magnus steel-template jacket and more than four time as much as the Eiffel Tower. At a cost of approximately $2.6 billion, the Magnus is the most expensive offshore platform to date. The Statfjord B was put into production in 1982. The Magnus is scheduled for oil production in 1983. The Hutton and the Block 280 will both be producing in 1984. (JMT)

  17. Disruption of Spectrin-Like Cytoskeleton in Differentiating Keratinocytes by PKCδ Activation Is Associated with Phosphorylated Adducin

    Science.gov (United States)

    Zhao, Kong-Nan; Masci, Paul P.; Lavin, Martin F.

    2011-01-01

    Spectrin is a central component of the cytoskeletal protein network in a variety of erythroid and non-erythroid cells. In keratinocytes, this protein has been shown to be pericytoplasmic and plasma membrane associated, but its characteristics and function have not been established in these cells. Here we demonstrate that spectrin increases dramatically in amount and is assembled into the cytoskeleton during differentiation in mouse and human keratinocytes. The spectrin-like cytoskeleton was predominantly organized in the granular and cornified layers of the epidermis and disrupted by actin filament inhibitors, but not by anti-mitotic drugs. When the cytoskeleton was disrupted PKCδ was activated by phosphorylation on Thr505. Specific inhibition of PKCδ(Thr505) activation with rottlerin prevented disruption of the spectrin-like cytoskeleton and the associated morphological changes that accompany differentiation. Rottlerin also inhibited specific phosphorylation of the PKCδ substrate adducin, a cytoskeletal protein. Furthermore, knock-down of endogenous adducin affected not only expression of adducin, but also spectrin and PKCδ, and severely disrupted organization of the spectrin-like cytoskeleton and cytoskeletal distribution of both adducin and PKCδ. These results demonstrate that organization of a spectrin-like cytoskeleton is associated with keratinocytes differentiation, and disruption of this cytoskeleton is mediated by either PKCδ(Thr505) phosphorylation associated with phosphorylated adducin or due to reduction of endogenous adducin, which normally connects and stabilizes the spectrin-actin complex. PMID:22163289

  18. Disruption of spectrin-like cytoskeleton in differentiating keratinocytes by PKCδ activation is associated with phosphorylated adducin.

    Directory of Open Access Journals (Sweden)

    Kong-Nan Zhao

    Full Text Available Spectrin is a central component of the cytoskeletal protein network in a variety of erythroid and non-erythroid cells. In keratinocytes, this protein has been shown to be pericytoplasmic and plasma membrane associated, but its characteristics and function have not been established in these cells. Here we demonstrate that spectrin increases dramatically in amount and is assembled into the cytoskeleton during differentiation in mouse and human keratinocytes. The spectrin-like cytoskeleton was predominantly organized in the granular and cornified layers of the epidermis and disrupted by actin filament inhibitors, but not by anti-mitotic drugs. When the cytoskeleton was disrupted PKCδ was activated by phosphorylation on Thr505. Specific inhibition of PKCδ(Thr505 activation with rottlerin prevented disruption of the spectrin-like cytoskeleton and the associated morphological changes that accompany differentiation. Rottlerin also inhibited specific phosphorylation of the PKCδ substrate adducin, a cytoskeletal protein. Furthermore, knock-down of endogenous adducin affected not only expression of adducin, but also spectrin and PKCδ, and severely disrupted organization of the spectrin-like cytoskeleton and cytoskeletal distribution of both adducin and PKCδ. These results demonstrate that organization of a spectrin-like cytoskeleton is associated with keratinocytes differentiation, and disruption of this cytoskeleton is mediated by either PKCδ(Thr505 phosphorylation associated with phosphorylated adducin or due to reduction of endogenous adducin, which normally connects and stabilizes the spectrin-actin complex.

  19. EURESCOM Services Platform

    NARCIS (Netherlands)

    Nieuwenhuis, Lambertus Johannes Maria; van Halteren, Aart

    1999-01-01

    This paper presents the results of the EURESCOM Project 715. In February 1999, a large team of researchers from six European public network operators completed a two year period of cooperative experiments on a TINA-based environment, called the EURESCOM Services Platform (ESP). This platform

  20. Probe tip heating assembly

    Science.gov (United States)

    Schmitz, Roger William; Oh, Yunje

    2016-10-25

    A heating assembly configured for use in mechanical testing at a scale of microns or less. The heating assembly includes a probe tip assembly configured for coupling with a transducer of the mechanical testing system. The probe tip assembly includes a probe tip heater system having a heating element, a probe tip coupled with the probe tip heater system, and a heater socket assembly. The heater socket assembly, in one example, includes a yoke and a heater interface that form a socket within the heater socket assembly. The probe tip heater system, coupled with the probe tip, is slidably received and clamped within the socket.

  1. [Regulation of cortical cytoskeleton dynamics during migration of free-living amoebae].

    Science.gov (United States)

    Kłopocka, Wanda; Redowicz, Maria Jolanta; Wasik, Anna

    2009-01-01

    Amoeba proteus and smaller by an order of magnitude (and evolutionary younger) Acanthamoeba castellanii have been for many years model cells for studies of amoeboidal (crawling) type of movement, characteristic also for some of metazoan cells such as fibroblasts, granulocytes and macrophages. Amoeboidal migration is indispensable of organization and dynamics of actin-based cytoskeleton. While there is a number of data on molecular mechanisms of motility of A. castellanii, there is very little known about bases of migration of A. proteus. Noteworthy, a large A. proteus (length approximately 600 microm) have been from over a century an object for studies on biology and physiology of cellular migration. This review describes the current knowledge on molecular aspects of force generation required for migration of these two amoebae and attempts to compare the functioning and regulation of actin cytoskeleton in these free-living unicellular species.

  2. The Gas2 family protein Pigs is a microtubule +TIP that affects cytoskeleton organisation.

    Science.gov (United States)

    Girdler, Gemma C; Applewhite, Derek A; Perry, Wick M G; Rogers, Stephen L; Röper, Katja

    2016-01-01

    Coordination between different cytoskeletal systems is crucial for many cell biological functions, including cell migration and mitosis, and also plays an important role during tissue morphogenesis. Proteins of the class of cytoskeletal crosslinkers, or cytolinkers, have the ability to interact with more than one cytoskeletal system at a time and are prime candidates to mediate any coordination. One such class comprises the Gas2-like proteins, combining a conserved calponin-homology-type actin-binding domain and a Gas2 domain predicted to bind microtubules (MTs). This domain combination is also found in spectraplakins, huge cytolinkers that play important roles in many tissues in both invertebrates and vertebrates. Here, we dissect the ability of the single Drosophila Gas2-like protein Pigs to interact with both actin and MT cytoskeletons, both in vitro and in vivo, and illustrate complex regulatory interactions that determine the localisation of Pigs to and its effects on the cytoskeleton.

  3. Adenomatous polyposis coli regulates axon arborization and cytoskeleton organization via its N-terminus.

    Directory of Open Access Journals (Sweden)

    Youjun Chen

    Full Text Available Conditional deletion of APC leads to marked disruption of cortical development and to excessive axonal branching of cortical neurons. However, little is known about the cell biological basis of this neuronal morphological regulation. Here we show that APC deficient cortical neuronal growth cones exhibit marked disruption of both microtubule and actin cytoskeleton. Functional analysis of the different APC domains revealed that axonal branches do not result from stabilized β-catenin, and that the C-terminus of APC containing microtubule regulatory domains only partially rescues the branching phenotype. Surprisingly, the N-terminus of APC containing the oligomerization domain and the armadillo repeats completely rescues the branching and cytoskeletal abnormalities. Our data indicate that APC is required for appropriate axon morphological development and that the N-terminus of APC is important for regulation of the neuronal cytoskeleton.

  4. Temperature response of the neuronal cytoskeleton mapped via atomic force and fluorescence microscopy

    CERN Document Server

    Spedden, Elise; Staii, Cristian

    2013-01-01

    Neuronal cells change their growth properties in response to external physical stimuli such as variations in external temperature, stiffness of the growth substrate, or topographical guidance cues. Detailed knowledge of the mechanisms that control these biomechanical responses is necessary for understanding the basic principles that underlie neuronal growth and regeneration. Here, we present elasticity maps of living cortical neurons (embryonic rat) as a function of temperature, and correlate these maps to the locations of internal structural components of the cytoskeleton. Neurons display a significant increase in the average elastic modulus upon a decrease in ambient temperature from 37{\\deg}C to 25{\\deg}C. We demonstrate that the dominant mechanism by which the elasticity of the neurons changes in response to temperature is the stiffening of the actin components of the cytoskeleton induced by myosin II. We also report a reversible shift in the location and composition of the high-stiffness areas of the neu...

  5. [Mechanical characteristics of synthetic polyelectrolyte gel as a physical model of the cytoskeleton].

    Science.gov (United States)

    Shkliar, T F; Toropova, O A; Safronov, A P; Pollack, G H; Bliakhman, F A

    2011-01-01

    A physical model of the cytoskeleton based on synthetic polyelectrolyte hydrogel of polymethacrylic acid has been proposed. From the physicochemical point of view, the structures of polyelectrolyte gel and the cytoskeleton show a high degree of similarity. It was shown that polyelectrolyte gel can shorten and produce mechanical stress in response to changes in the composition of the surrounding solution. The mechanical properties of the model gel were evaluated: Young modulus (2-6 kPa), stress relaxation time (0.1-1 s), and apparent viscosity (0.3-3 kPa x s). The viscoelastic properties of the gel depend on the degree of its swelling. It has been demonstrated that the mechanical properties of gels of polymethacrylic acid are close to those of biological objects.

  6. JVG9, a benzimidazole derivative, alters the surface and cytoskeleton of Trypanosoma cruzi bloodstream trypomastigotes

    Science.gov (United States)

    Díaz-Chiguer, Dylan L; Hernández-Luis, Francisco; Nogueda-Torres, Benjamín; Castillo, Rafael; Reynoso-Ducoing, Olivia; Hernández-Campos, Alicia; Ambrosio, Javier R

    2014-01-01

    Trypanosoma cruzi has a particular cytoskeleton that consists of a subpellicular network of microtubules and actin microfilaments. Therefore, it is an excellent target for the development of new anti-parasitic drugs. Benzimidazole 2-carbamates, a class of well-known broad-spectrum anthelmintics, have been shown to inhibit the in vitro growth of many protozoa. Therefore, to find efficient anti-trypanosomal (trypanocidal) drugs, our group has designed and synthesised several benzimidazole derivatives. One, named JVG9 (5-chloro-1H-benzimidazole-2-thiol), has been found to be effective against T. cruzi bloodstream trypomastigotes under both in vitro and in vivo conditions. Here, we present the in vitro effects observed by laser scanning confocal and scanning electron microscopy on T. cruzi trypomastigotes. Changes in the surface and the distribution of the cytoskeletal proteins are consistent with the hypothesis that the trypanocidal activity of JVG9 involves the cytoskeleton as a target. PMID:25317703

  7. Stiffening of Red Blood Cells Induced by Disordered Cytoskeleton Structures: A Joint Theory-experiment Study

    CERN Document Server

    Lai, Lipeng; Lim, Chwee Teck; Cao, Jianshu

    2015-01-01

    The functions and elasticities of the cell are largely related to the structures of the cytoskeletons underlying the lipid bi-layer. Among various cell types, the Red Blood Cell (RBC) possesses a relatively simple cytoskeletal structure. Underneath the membrane, the RBC cytoskeleton takes the form of a two dimensional triangular network, consisting of nodes of actins (and other proteins) and edges of spectrins. Recent experiments focusing on the malaria infected RBCs (iRBCs) showed that there is a correlation between the elongation of spectrins in the cytoskeletal network and the stiffening of the iRBCs. Here we rationalize the correlation between these two observations by combining the worm-like chain (WLC) model for single spectrins and the Effective Medium Theory (EMT) for the network elasticity. We specifically focus on how the disorders in the cytoskeletal network affect its macroscopic elasticity. Analytical and numerical solutions from our model reveal that the stiffness of the membrane increases with ...

  8. Imaging the fine-scale structure of the cellular actin cytoskeleton by Single Particle Tracking and Atomic Force Microscopy

    Science.gov (United States)

    Mustata, Gina-Mirela

    It has been proposed that diffusion in the plasma membrane of eukaryotic cells it is compartmentalized due to the interaction with the underlying actin-based membrane skeleton that comes into close proximity to the lipid bilayer. The cytoskeleton is a dynamic structure that maintains cell shape, enables cell motion, and plays important roles in both intra-cellular transport and cellular division. We show here the evidence of plasma membrane compartmentalization using Single Particle Tracking (SPT) and Atomic Force Microscopy (AFM) imaging. SPT of Quantum dot labeled lipid in the plasma membrane of live normal rat kidney cells show compartments ranging from 325 nm to 391 nm depending on the sampling time. Using AFM imaging of live NRK cell in the presence of phalloidin, the membrane compartmentalization it is visible with the average size of the compartments of 325 +/- 10 nm (the main peak is centered at 260 nm). Further, the underlying membrane skeleton in fixed cells was directly imaged after partial removal of the plasma membrane to reveal size of the membrane skeleton meshwork of 339 +/- 10 nm. A new method of measuring the characteristics of the actin meshwork was proposed. Probing the local compliance of the plasma membrane through the deflection of a soft AFM cantilever we can expect that the stiffness of the membrane will be higher at locations directly above a cortical actin. This new method provided information about the structure of the skeletal meshwork of neuronal cell body predicting an average compartment size of about 132 nm. This was confirmed through SPT of QD-lipid incorporated into the neuronal cell membrane.

  9. A novel mouse model of Warburg Micro syndrome reveals roles for RAB18 in eye development and organisation of the neuronal cytoskeleton

    Directory of Open Access Journals (Sweden)

    Sarah M. Carpanini

    2014-06-01

    Full Text Available Mutations in RAB18 have been shown to cause the heterogeneous autosomal recessive disorder Warburg Micro syndrome (WARBM. Individuals with WARBM present with a range of clinical symptoms, including ocular and neurological abnormalities. However, the underlying cellular and molecular pathogenesis of the disorder remains unclear, largely owing to the lack of any robust animal models that phenocopy both the ocular and neurological features of the disease. We report here the generation and characterisation of a novel Rab18-mutant mouse model of WARBM. Rab18-mutant mice are viable and fertile. They present with congenital nuclear cataracts and atonic pupils, recapitulating the characteristic ocular features that are associated with WARBM. Additionally, Rab18-mutant cells exhibit an increase in lipid droplet size following treatment with oleic acid. Lipid droplet abnormalities are a characteristic feature of cells taken from WARBM individuals, as well as cells taken from individuals with other neurodegenerative conditions. Neurological dysfunction is also apparent in Rab18-mutant mice, including progressive weakness of the hind limbs. We show that the neurological defects are, most likely, not caused by gross perturbations in synaptic vesicle recycling in the central or peripheral nervous system. Rather, loss of Rab18 is associated with widespread disruption of the neuronal cytoskeleton, including abnormal accumulations of neurofilament and microtubule proteins in synaptic terminals, and gross disorganisation of the cytoskeleton in peripheral nerves. Global proteomic profiling of peripheral nerves in Rab18-mutant mice reveals significant alterations in several core molecular pathways that regulate cytoskeletal dynamics in neurons. The apparent similarities between the WARBM phenotype and the phenotype that we describe here indicate that the Rab18-mutant mouse provides an important platform for investigation of the disease pathogenesis and therapeutic

  10. Near-critical fluctuations and cytoskeleton-assisted phase separation lead to subdiffusion in cell membranes

    CERN Document Server

    Ehrig, Jens; Schwille, Petra

    2010-01-01

    We address the relationship between membrane microheterogeneity and anomalous subdiffusion in cell membranes by carrying out Monte Carlo simulations of two-component lipid membranes. We find that near-critical fluctuations in the membrane lead to transient subdiffusion, while membrane-cytoskeleton interaction strongly affects phase separation, enhances subdiffusion, and eventually leads to hop diffusion of lipids. Thus, we present a minimum realistic model for membrane rafts showing the features of both microscopic phase separation and subdiffusion.

  11. An actin cytoskeleton with evolutionarily conserved functions in the absence of canonical actin-binding proteins

    OpenAIRE

    Paredez, Alexander R.; Assaf, Zoe June; Sept, David; Timofejeva, Ljudmilla; Dawson, Scott C.; Wang, Chung-Ju Rachel; Cande, W. Z.

    2011-01-01

    Giardia intestinalis, a human intestinal parasite and member of what is perhaps the earliest-diverging eukaryotic lineage, contains the most divergent eukaryotic actin identified to date and is the first eukaryote known to lack all canonical actin-binding proteins (ABPs). We sought to investigate the properties and functions of the actin cytoskeleton in Giardia to determine whether Giardia actin (giActin) has reduced or conserved roles in core cellular processes. In vitro polymerization of gi...

  12.  Oxidative stress modulates the organization of erythrocyte membrane cytoskeleton

    Directory of Open Access Journals (Sweden)

    Maria Olszewska

    2012-07-01

    Full Text Available  Background:Apart from their main role in transporting oxygen and carbon dioxide, erythrocytes play also an important role in organism antioxidative defence. Direct exposure to reactive oxygen species (ROS results in shortening of their half-life, even by 50�20The presence of glucose, being the substrate in pentose phosphate pathway (PPP cycle, is one of the factors that can have influence on the level of oxidative stress. The activity of PPP increases during oxidative stress. Glucose guarantees normal PPP functioning with the production of reductive equivalents in the amounts necessary to reproduction of glutathione – nonenzymatic free radical scavenger. In available literature there are no reports regarding the changes in protein contents of erythrocyte cytoskeleton exposed to t-butyl hydroperoxide in relation to glucose presence in incubation medium.Material/methods:Erythrocytes taken from 10 healthy subjects were used to assess the influence of generated free radicals on erythrocyte proteins and chosen parameters of oxidative stress. Erythrocytes were incubated in the solutions containing deferent concentrations of t-butyl hydroperoxide and glucose. Electrophoresis was performed on polyacrylamide gel in denaturating conditions. The contents of tryptophan in membranes was evaluated spectrofluorometrically.Results/conclusions:In vitro conditions oxidative stress leads to protein damage in erythrocyte cytoskeleton, both in proteins inside the cell as well as having contact with extracellular environment. In consequence, the amount of low-molecular proteins – mainly globin, which bind to cytoskeleton, increases. This process takes place independently of glucose presence in incubation medium. One of the element of protein cytoskeleton, tryptophan, also undergoes degradation. The decrease of its contents is higher during erythrocyte exposure to t-BOOH in environment containing glucose, what can suggest prooxidative influence of glucose in

  13. Hepatocyte cytoskeleton during ischemia and reperfusion influence of ANP-mediated p38 MAPK activation

    Institute of Scientific and Technical Information of China (English)

    Melanie Keller; Alexander L Gerbes; Stefanie Kulhanek-Heinze; Tobias Gerwig; Uwe Grützner; Nico van Rooijen; Angelika M Vollmar; Alexandra K Kiemer

    2005-01-01

    AIM: To determine functional consequences of this activation, whereby we focused on a potential regulation of the hepatocyte cytoskeleton during ischemia and reperfusion.METHODS: For in vivo experiments, animals received ANP (5 μg/kg) intravenously. In a different experimental setting, isolated rat livers were perfused with KH-buffer ±ANP (200 nmol/L)±SB203580 (2 μmol/L). Liverswere then kept under ischemic conditions for 24 h, and either transplanted or reperfused. Actin, Hsp27, and phosphorylated Hsp27 were determined by Western blotting, p38 MAPK activity by in vitro phosphorylation assay. F-actin distribution was determined by confocal microscopy.RESULTS: We first confirmed that ANP preconditioning leads to an activation of p38 MAPK and observedalterations of the cytoskeleton in hepatocytes of ANPpreconditioned organs. ANP induced an increase of hepatic F-actin after ischemia, which could be prevented by the p38 MAPK inhibitor SB203580 but had no effect on bile flow. After ischemia untreated livers showed a translocation of Hsp27 towards the cytoskeleton and an increase in total Hsp27, whereas ANP preconditioning prohibited translocation but caused an augmentation of Hsp27 phosphorylation. This effect is also mediated via p38 MAPK, since it was abrogated by the p38 MAPK inhibitor SB203580.CONCLUSION: This study reveals that ANP-mediated p38 MAPK activation leads to changes in hepatocyte cytoskeleton involving an elevation of phosphorylated Hsp27 and thereby for the first time shows functional consequences of ANP-induced hepatic p38 MAPK activation.

  14. The Common HOL Platform

    OpenAIRE

    Adams, Mark

    2015-01-01

    The Common HOL project aims to facilitate porting source code and proofs between members of the HOL family of theorem provers. At the heart of the project is the Common HOL Platform, which defines a standard HOL theory and API that aims to be compatible with all HOL systems. So far, HOL Light and hol90 have been adapted for conformance, and HOL Zero was originally developed to conform. In this paper we provide motivation for a platform, give an overview of the Common HOL Platform's theory and...

  15. Ladder attachment platform

    Science.gov (United States)

    Swygert,; Richard, W [Springfield, SC

    2012-08-28

    A ladder attachment platform is provided that includes a base for attachment to a ladder that has first and second side rails and a plurality of rungs that extend between in a lateral direction. Also included is a user platform for having a user stand thereon that is carried by the base. The user platform may be positioned with respect to the ladder so that it is not located between a first plane that extends through the first side rail and is perpendicular to the lateral direction and a second plane that extends through the second side rail and is perpendicular to the lateral direction.

  16. Pathogenesis of common glomerular diseases – role of the podocyte cytoskeleton

    Directory of Open Access Journals (Sweden)

    Kumagai T

    2012-10-01

    Full Text Available Takanori Kumagai, Flaviana Mouawad, Tomoko TakanoDepartment of Medicine, McGill University Health Centre, Montreal, Quebec, CanadaAbstract: Glomerulus is the filtration unit of the kidney where the first step of urine formation takes place. In the glomerulus, water and small molecules including waste products of the body are filtered into the urine, while large molecules essential for body function such as albumin are retained. When this barrier function of the kidney is impaired, protein leakage into the urine (proteinuria occurs. Proteinuria is not only a hallmark of many glomerular diseases but also a prognostic marker of kidney disease progression. Visceral glomerular epithelial cells (commonly called podocytes are known to have an important role in the maintenance of glomerular barrier function. In the last decade, remarkable progress has been made in podocyte biology, mainly led by the discoveries of important proteins that work together to maintain the intricate morphology and function of podocytes. Most of these so-called podocyte proteins modulate the actin cytoskeleton either directly or indirectly. The aim of the current review is to discuss the pathogenesis of common glomerular diseases with a particular focus on the role of the actin cytoskeleton in podocytes. The diseases covered include minimal change disease, focal segmental glomerulosclerosis (idiopathic and hereditary, membranous nephropathy, hypertensive glomerulosclerosis, and diabetic nephropathy.Keywords: glomerular disease, podocyte, cytoskeleton, proteinuria

  17. Hijacking host cell highways: manipulation of the host actin cytoskeleton by obligate intracellular bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Punsiri M Colonne

    2016-09-01

    Full Text Available Intracellular bacterial pathogens replicate within eukaryotic cells and display unique adaptations that support key infection events including invasion, replication, immune evasion, and dissemination. From invasion to dissemination, all stages of the intracellular bacterial life cycle share the same three-dimensional cytosolic space containing the host cytoskeleton. For successful infection and replication, many pathogens hijack the cytoskeleton using effector proteins introduced into the host cytosol by specialized secretion systems. A subset of effectors contains eukaryotic-like motifs that mimic host proteins to exploit signaling and modify specific cytoskeletal components such as actin and microtubules. Cytoskeletal rearrangement promotes numerous events that are beneficial to the pathogen, including internalization of bacteria, subversion of cell intrinsic immunity, structural support for bacteria-containing vacuoles, altered vesicular trafficking, actin-dependent bacterial movement, and pathogen dissemination. This review highlights a diverse group of obligate intracellular bacterial pathogens that manipulate the host cytoskeleton to thrive within eukaryotic cells and discusses underlying molecular mechanisms that promote these dynamic host-pathogen interactions.

  18. Distinct impact of targeted actin cytoskeleton reorganization on mechanical properties of normal and malignant cells.

    Science.gov (United States)

    Efremov, Yu M; Dokrunova, A A; Efremenko, A V; Kirpichnikov, M P; Shaitan, K V; Sokolova, O S

    2015-11-01

    The actin cytoskeleton is substantially modified in cancer cells because of changes in actin-binding protein abundance and functional activity. As a consequence, cancer cells have distinctive motility and mechanical properties, which are important for many processes, including invasion and metastasis. Here, we studied the effects of actin cytoskeleton alterations induced by specific nucleation inhibitors (SMIFH2, CK-666), cytochalasin D, Y-27632 and detachment from the surface by trypsinization on the mechanical properties of normal Vero and prostate cancer cell line DU145. The Young's modulus of Vero cells was 1300±900 Pa, while the prostate cancer cell line DU145 exhibited significantly lower Young's moduli (600±400 Pa). The Young's moduli exhibited a log-normal distribution for both cell lines. Unlike normal cells, cancer cells demonstrated diverse viscoelastic behavior and different responses to actin cytoskeleton reorganization. They were more resistant to specific formin-dependent nucleation inhibition, and reinforced their cortical actin after detachment from the substrate. This article is part of a Special Issue entitled: Mechanobiology.

  19. p38α regulates actin cytoskeleton and cytokinesis in hepatocytes during development and aging.

    Science.gov (United States)

    Tormos, Ana M; Rius-Pérez, Sergio; Jorques, María; Rada, Patricia; Ramirez, Lorena; Valverde, Ángela M; Nebreda, Ángel R; Sastre, Juan; Taléns-Visconti, Raquel

    2017-01-01

    Hepatocyte poliploidization is an age-dependent process, being cytokinesis failure the main mechanism of polyploid hepatocyte formation. Our aim was to study the role of p38α MAPK in the regulation of actin cytoskeleton and cytokinesis in hepatocytes during development and aging. Wild type and p38α liver-specific knock out mice at different ages (after weaning, adults and old) were used. We show that p38α MAPK deficiency induces actin disassembly upon aging and also cytokinesis failure leading to enhanced binucleation. Although the steady state levels of cyclin D1 in wild type and p38α knock out old livers remained unaffected, cyclin B1- a marker for G2/M transition- was significantly overexpressed in p38α knock out mice. Our findings suggest that hepatocytes do enter into S phase but they do not complete cell division upon p38α deficiency leading to cytokinesis failure and binucleation. Moreover, old liver-specific p38α MAPK knock out mice exhibited reduced F-actin polymerization and a dramatic loss of actin cytoskeleton. This was associated with abnormal hyperactivation of RhoA and Cdc42 GTPases. Long-term p38α deficiency drives to inactivation of HSP27, which seems to account for the impairment in actin cytoskeleton as Hsp27-silencing decreased the number and length of actin filaments in isolated hepatocytes. p38α MAPK is essential for actin dynamics with age in hepatocytes.

  20. The role of the cytoskeleton in cellular force generation in 2D and 3D environments

    Science.gov (United States)

    Kraning-Rush, Casey M.; Carey, Shawn P.; Califano, Joseph P.; Smith, Brooke N.; Reinhart-King, Cynthia A.

    2011-02-01

    To adhere and migrate, cells generate forces through the cytoskeleton that are transmitted to the surrounding matrix. While cellular force generation has been studied on 2D substrates, less is known about cytoskeletal-mediated traction forces of cells embedded in more in vivo-like 3D matrices. Recent studies have revealed important differences between the cytoskeletal structure, adhesion, and migration of cells in 2D and 3D. Because the cytoskeleton mediates force, we sought to directly compare the role of the cytoskeleton in modulating cell force in 2D and 3D. MDA-MB-231 cells were treated with agents that perturbed actin, microtubules, or myosin, and analyzed for changes in cytoskeletal organization and force generation in both 2D and 3D. To quantify traction stresses in 2D, traction force microscopy was used; in 3D, force was assessed based on single cell-mediated collagen fibril reorganization imaged using confocal reflectance microscopy. Interestingly, even though previous studies have observed differences in cell behaviors like migration in 2D and 3D, our data indicate that forces generated on 2D substrates correlate with forces within 3D matrices. Disruption of actin, myosin or microtubules in either 2D or 3D microenvironments disrupts cell-generated force. These data suggest that despite differences in cytoskeletal organization in 2D and 3D, actin, microtubules and myosin contribute to contractility and matrix reorganization similarly in both microenvironments.

  1. Actin cytoskeleton contributes to the elastic modulus of embryonic tendon during early development.

    Science.gov (United States)

    Schiele, Nathan R; von Flotow, Friedrich; Tochka, Zachary L; Hockaday, Laura A; Marturano, Joseph E; Thibodeau, Jeffrey J; Kuo, Catherine K

    2015-06-01

    Tendon injuries are common and heal poorly. Strategies to regenerate or replace injured tendons are challenged by an incomplete understanding of normal tendon development. Our previous study showed that embryonic tendon elastic modulus increases as a function of developmental stage. Inhibition of enzymatic collagen crosslink formation abrogated increases in tendon elastic modulus at late developmental stages, but did not affect increases in elastic modulus of early stage embryonic tendons. Here, we aimed to identify potential contributors to the mechanical properties of these early stage embryonic tendons. We characterized tendon progenitor cells in early stage embryonic tendons, and the influence of actin cytoskeleton disruption on tissue elastic modulus. Cells were closely packed in embryonic tendons, and did not change in density during early development. We observed an organized network of actin filaments that seemed contiguous between adjacent cells. The actin filaments exhibited a crimp pattern with a period and amplitude that matched the crimp of collagen fibers at each developmental stage. Chemical disruption of the actin cytoskeleton decreased tendon tissue elastic modulus, measured by atomic force microscopy. Our results demonstrate that early developmental stage embryonic tendons possess a well organized actin cytoskeleton network that contributes significantly to tendon tissue mechanical properties. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  2. The Hippo pathway polarizes the actin cytoskeleton during collective migration of Drosophila border cells.

    Science.gov (United States)

    Lucas, Eliana P; Khanal, Ichha; Gaspar, Pedro; Fletcher, Georgina C; Polesello, Cedric; Tapon, Nicolas; Thompson, Barry J

    2013-06-10

    Collective migration of Drosophila border cells depends on a dynamic actin cytoskeleton that is highly polarized such that it concentrates around the outer rim of the migrating cluster of cells. How the actin cytoskeleton becomes polarized in these cells to enable collective movement remains unknown. Here we show that the Hippo signaling pathway links determinants of cell polarity to polarization of the actin cytoskeleton in border cells. Upstream Hippo pathway components localize to contacts between border cells inside the cluster and signal through the Hippo and Warts kinases to polarize actin and promote border cell migration. Phosphorylation of the transcriptional coactivator Yorkie (Yki)/YAP by Warts does not mediate the function of this pathway in promoting border cell migration, but rather provides negative feedback to limit the speed of migration. Instead, Warts phosphorylates and inhibits the actin regulator Ena to activate F-actin Capping protein activity on inner membranes and thereby restricts F-actin polymerization mainly to the outer rim of the migrating cluster.

  3. The ion channels to cytoskeleton connection as potential mechanism of mechanosensitivity.

    Science.gov (United States)

    Martinac, Boris

    2014-02-01

    As biological force-sensing systems mechanosensitive (MS) ion channels present the best example of coupling molecular dynamics of membrane proteins to the mechanics of the surrounding cell membrane. In animal cells MS channels have over the past two decades been very much in focus of mechanotransduction research. In recent years this helped to raise awareness of basic and medical researchers about the role that abnormal MS channels may play in the pathophysiology of diseases, such as cardiac hypertrophy, atrial fibrillation, muscular dystrophy or polycystic kidney disease. To date a large number of MS channels from organisms of diverse phylogenetic origins have been identified at the molecular level; however, the structure of only few of them has been determined. Although their function has extensively been studied in a great variety of cells and tissues by different experimental approaches it is, with exception of bacterial MS channels, very little known about how these channels sense mechanical force and which cellular components may contribute to their function. By focusing on MS channels found in animal cells this article discusses the ways in which the connections between cytoskeleton and ion channels may contribute to mechanosensory transduction in these cells. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.

  4. p38α regulates actin cytoskeleton and cytokinesis in hepatocytes during development and aging

    Science.gov (United States)

    Jorques, María; Rada, Patricia; Ramirez, Lorena; Valverde, Ángela M.; Nebreda, Ángel R.; Sastre, Juan

    2017-01-01

    Background Hepatocyte poliploidization is an age-dependent process, being cytokinesis failure the main mechanism of polyploid hepatocyte formation. Our aim was to study the role of p38α MAPK in the regulation of actin cytoskeleton and cytokinesis in hepatocytes during development and aging. Methods Wild type and p38α liver-specific knock out mice at different ages (after weaning, adults and old) were used. Results We show that p38α MAPK deficiency induces actin disassembly upon aging and also cytokinesis failure leading to enhanced binucleation. Although the steady state levels of cyclin D1 in wild type and p38α knock out old livers remained unaffected, cyclin B1- a marker for G2/M transition- was significantly overexpressed in p38α knock out mice. Our findings suggest that hepatocytes do enter into S phase but they do not complete cell division upon p38α deficiency leading to cytokinesis failure and binucleation. Moreover, old liver-specific p38α MAPK knock out mice exhibited reduced F-actin polymerization and a dramatic loss of actin cytoskeleton. This was associated with abnormal hyperactivation of RhoA and Cdc42 GTPases. Long-term p38α deficiency drives to inactivation of HSP27, which seems to account for the impairment in actin cytoskeleton as Hsp27-silencing decreased the number and length of actin filaments in isolated hepatocytes. Conclusions p38α MAPK is essential for actin dynamics with age in hepatocytes. PMID:28166285

  5. Rho proteins − the key regulators of cytoskeleton in the progression of mitosis and cytokinesis

    Directory of Open Access Journals (Sweden)

    Anna Klimaszewska

    2011-11-01

    Full Text Available The Rho proteins are members of the Ras superfamily of small GTPases. They are thought to be crucial regulators of multiple signal transduction pathways that influence a wide range of cellular functions, including migration, membrane trafficking, adhesion, polarity and cell shape changes. Thanks to their ability to control the assembly and organization of the actin and microtubule cytoskeletons, Rho GTPases are known to regulate mitosis and cytokinesis progression. These proteins are required for formation and rigidity of the cortex during mitotic cell rounding, mitotic spindle formation and attachment of the spindle microtubules to the kinetochore. In addition, during cytokinesis, they are involved in promoting division plane determination, contractile ring and cleavage furrow formation and abscission. They are also known as regulators of cell cycle progression at the G1/S and G2/M transition. Thus, the signal transduction pathways in which Rho proteins participate, appear to connect dynamics of actin and microtubule cytoskeletons to cell cycle progression. We review the current state of knowledge concerning the molecular mechanisms by which Rho GTPase signaling regulates remodeling of actin and microtubule cytoskeletons in order to control cell division progression.

  6. Application of GFP technique for cytoskeleton visualization onboard the International Space Station.

    Science.gov (United States)

    Kordyum, E L; Shevchenko, G V; Yemets, A I; Nyporko, A I; Blume, Ya B

    2005-03-01

    Cytoskeleton recently attracted wide attention of cell and molecular biologists due to its crucial role in gravity sensing and trunsduction. Most of cytoskeletal research is conducted by the means of immunohistochemical reactions, different modifications of which are beneficial for the ground-based experiments. But for the performance onboard the space vehicles, they represent quite complicated technique which requires time and special skills for astronauts. In addition, immunocytochemistry provides only static images of the cytoskeleton arrangement in fixed cells while its localization in living cells is needed for the better understanding of cytoskeletal function. In this connection, we propose a new approach for cytoskeletal visualization onboard the ISS, namely, application of green fluorescent protein (GFP) from Aequorea victoria, which has the unique properties as a marker for protein localization in vivo. The creation of chimerical protein-GFP gene constructs, obtaining the transformed plant cells possessed protein-GFP in their cytoskeletal composition will allow receiving a simple and efficient model for screening of the cytoskeleton functional status in microgravity.

  7. Cytoskeleton and Golgi-apparatus interactions: a two-way road of function and structure

    Directory of Open Access Journals (Sweden)

    Egea G

    2015-01-01

    Full Text Available Gustavo Egea,1 Carla Serra-Peinado,1 María P Gavilan,2 Rosa M Rios21Departament de Biologia Cel·lular, Immulogia i Neurociències, Facultat de Medicina and Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS, Universitat de Barcelona, Barcelona, Spain; 2Departamento de Señalización Celular, CSIC-Centro Andaluz de Biomedicina y Medicina Regenerativa (CABIMER, Seville, SpainAbstract: The Golgi apparatus is the result of a complex and dynamic interaction between a large variety of molecules that determine its architecture, protein and lipid transports, and those that integrate signals from outside and inside the cell. The cytoskeleton facilitates the functional integration of all these processes. Association and coordination between microtubules and actin filaments, as well as their respective binding and regulatory proteins, are clearly necessary for Golgi structure and function. Protein sorting, membrane fission and fusion, and the motion of Golgi-derived transport carriers are all affected by both cytoskeleton elements.Keywords: cytoskeleton, Golgi apparatus, membrane trafficking, secretory pathway, actin, microtubules

  8. 3D culture increases pluripotent gene expression in mesenchymal stem cells through relaxation of cytoskeleton tension.

    Science.gov (United States)

    Zhou, Ying; Chen, Haiyan; Li, Hong; Wu, Yaojiong

    2017-03-09

    Three-dimensional (3D) culture has been shown to improve pluripotent gene expression in mesenchymal stem cells (MSCs), but the underlining mechanisms were poorly understood. Here, we found that the relaxation of cytoskeleton tension of MSCs in 3D culture was critically associated with the expressional up-regulation of Nanog. Cultured in spheroids, MSCs showed decreased integrin-based cell-matrix adhesion but increased cadherin-based cell-cell interaction. Different from that in 2D culture, where MSCs exhibited branched and multiple-directed F-actin stress bundles at the cell edge and strengthened stress fibres transversing the cell body, MSCs cultured in spheroids showed compact cell body, relaxed cytoskeleton tension with very thin cortical actin filament outlining the cell, and increased expression of Nanog along with reduced levels of Suv39h1 (H3K9 methyltransferase) and H3K9me3. Notably, pharmaceutical inhibition of actin polymerization with cytochalasin D or silencing Suv39h1 expression with siRNA in 2D-cultured MSCs elevated the expression of Nanog via H3K9 demethylation. Thus, our data suggest that 3D culture increases the expression of Nanog through the relaxation of actin cytoskeleton, which mediates reduced Suv39h1 and H3K9me3 levels.

  9. Focal adhesion kinase is required for actin polymerization and remodeling of the cytoskeleton during sperm capacitation

    Science.gov (United States)

    Roa-Espitia, Ana L.; Hernández-Rendón, Eva R.; Baltiérrez-Hoyos, Rafael; Muñoz-Gotera, Rafaela J.; Cote-Vélez, Antonieta; Jiménez, Irma; González-Márquez, Humberto

    2016-01-01

    ABSTRACT Several focal adhesion proteins are known to cooperate with integrins to link the extracellular matrix to the actin cytoskeleton; as a result, many intracellular signaling pathways are activated and several focal adhesion complexes are formed. However, how these proteins function in mammalian spermatozoa remains unknown. We confirm the presence of focal adhesion proteins in guinea pig spermatozoa, and we explore their role during capacitation and the acrosome reaction, and their relationship with the actin cytoskeleton. Our results suggest the presence of a focal adhesion complex formed by β1-integrin, focal adhesion kinase (FAK), paxillin, vinculin, talin, and α-actinin in the acrosomal region. Inhibition of FAK during capacitation affected the protein tyrosine phosphorylation associated with capacitation that occurs within the first few minutes of capacitation, which caused the acrosome reaction to become increasingly Ca2+ dependent and inhibited the polymerization of actin. The integration of vinculin and talin into the complex, and the activation of FAK and paxillin during capacitation, suggests that the complex assembles at this time. We identify that vinculin and α-actinin increase their interaction with F-actin while it remodels during capacitation, and that during capacitation focal adhesion complexes are structured. FAK contributes to acrosome integrity, likely by regulating the polymerization and the remodeling of the actin cytoskeleton. PMID:27402964

  10. Exploring the possible role of lysine acetylation on Entamoeba histolytica virulence: a focus on the dynamics of the actin cytoskeleton.

    Science.gov (United States)

    López-Contreras, L; Hernández-Ramírez, V I; Lagunes-Guillén, A E; Montaño, Sarita; Chávez-Munguía, B; Sánchez-Ramírez, B; Talamás-Rohana, P

    2013-01-01

    Cytoskeleton remodeling can be regulated, among other mechanisms, by lysine acetylation. The role of acetylation on cytoskeletal and other proteins of Entamoeba histolytica has been poorly studied. Dynamic rearrangements of the actin cytoskeleton are crucial for amebic motility and capping formation, processes that may be effective means of evading the host immune response. Here we report the possible effect of acetylation on the actin cytoskeleton dynamics and in vivo virulence of E. histolytica. Using western blot, immunoprecipitation, microscopy assays, and in silico analysis, we show results that strongly suggest that the increase in Aspirin-induced cytoplasm proteins acetylation reduced cell movement and capping formation, likely as a consequence of alterations in the structuration of the actin cytoskeleton. Additionally, intrahepatic inoculation of Aspirin-treated trophozoites in hamsters resulted in severe impairment of the amebic virulence. Taken together, these results suggest an important role for lysine acetylation in amebic invasiveness and virulence.

  11. Exploring the Possible Role of Lysine Acetylation on Entamoeba histolytica Virulence: A Focus on the Dynamics of the Actin Cytoskeleton

    Directory of Open Access Journals (Sweden)

    L. López-Contreras

    2013-01-01

    Full Text Available Cytoskeleton remodeling can be regulated, among other mechanisms, by lysine acetylation. The role of acetylation on cytoskeletal and other proteins of Entamoeba histolytica has been poorly studied. Dynamic rearrangements of the actin cytoskeleton are crucial for amebic motility and capping formation, processes that may be effective means of evading the host immune response. Here we report the possible effect of acetylation on the actin cytoskeleton dynamics and in vivo virulence of E. histolytica. Using western blot, immunoprecipitation, microscopy assays, and in silico analysis, we show results that strongly suggest that the increase in Aspirin-induced cytoplasm proteins acetylation reduced cell movement and capping formation, likely as a consequence of alterations in the structuration of the actin cytoskeleton. Additionally, intrahepatic inoculation of Aspirin-treated trophozoites in hamsters resulted in severe impairment of the amebic virulence. Taken together, these results suggest an important role for lysine acetylation in amebic invasiveness and virulence.

  12. Platform-based production development

    DEFF Research Database (Denmark)

    Bossen, Jacob; Brunoe, Thomas Ditlev; Nielsen, Kjeld

    2015-01-01

    Platforms as a means for applying modular thinking in product development is relatively well studied, but platforms in the production system has until now not been given much attention. With the emerging concept of platform-based co-development the importance of production platforms is though...... indisputable. This paper presents state-of-the-art literature on platform research related to production platforms and investigates gaps in the literature. The paper concludes on findings by proposing future research directions....

  13. Tank-Treading of Erythrocytes in Strong Shear Flows via a Nonstiff Cytoskeleton-Based Continuum Computational Modeling

    OpenAIRE

    Dodson, W. R.; Dimitrakopoulos, P.

    2010-01-01

    We develop a computationally efficient cytoskeleton-based continuum erythrocyte algorithm. The cytoskeleton is modeled as a two-dimensional elastic solid with comparable shearing and area-dilatation resistance that follows a material law (Skalak, R., A. Tozeren, R. P. Zarda, and S. Chien. 1973. Strain energy function of red blood cell membranes. Biophys. J. 13:245–264). Our modeling enforces the global area-incompressibility of the spectrin skeleton (being enclosed beneath the lipid bilayer i...

  14. Mobile Game Probes

    DEFF Research Database (Denmark)

    Borup Lynggaard, Aviaja

    2006-01-01

    This paper will examine how probes can be useful for game designers in the preliminary phases of a design process. The work is based upon a case study concerning pervasive mobile phone games where Mobile Game Probes have emerged from the project. The new probes are aimed towards a specific target...... group and the goal is to specify the probes so they will cover the most relevant areas for our project. The Mobile Game Probes generated many interesting results and new issues occurred, since the probes came to be dynamic and favorable for the process in new ways....

  15. Multiplex fluorescence melting curve analysis for mutation detection with dual-labeled, self-quenched probes.

    Directory of Open Access Journals (Sweden)

    Qiuying Huang

    Full Text Available Probe-based fluorescence melting curve analysis (FMCA is a powerful tool for mutation detection based on melting temperature generated by thermal denaturation of the probe-target hybrid. Nevertheless, the color multiplexing, probe design, and cross-platform compatibility remain to be limited by using existing probe chemistries. We hereby explored two dual-labeled, self-quenched probes, TaqMan and shared-stem molecular beacons, in their ability to conduct FMCA. Both probes could be directly used for FMCA and readily integrated with closed-tube amplicon hybridization under asymmetric PCR conditions. Improved flexibility of FMCA by using these probes was illustrated in three representative applications of FMCA: mutation scanning, mutation identification and mutation genotyping, all of which achieved improved color-multiplexing with easy probe design and versatile probe combination and all were validated with a large number of real clinical samples. The universal cross-platform compatibility of these probes-based FMCA was also demonstrated by a 4-color mutation genotyping assay performed on five different real-time PCR instruments. The dual-labeled, self-quenched probes offered unprecedented combined advantage of enhanced multiplexing, improved flexibility in probe design, and expanded cross-platform compatibility, which would substantially improve FMCA in mutation detection of various applications.

  16. USA Hire Testing Platform

    Data.gov (United States)

    Office of Personnel Management — The USA Hire Testing Platform delivers tests used in hiring for positions in the Federal Government. To safeguard the integrity of the hiring processes and ensure...

  17. MULTIFUNCTIONAL PLATFORMS AND

    African Journals Online (AJOL)

    Solar service centres and multifunctional platforms are innovative concepts for providing energy services in ... same time generate income. obeng ..... communities the driving force behind the ... operator(s) had to contact repairers outside their.

  18. The Common HOL Platform

    Directory of Open Access Journals (Sweden)

    Mark Adams

    2015-07-01

    Full Text Available The Common HOL project aims to facilitate porting source code and proofs between members of the HOL family of theorem provers. At the heart of the project is the Common HOL Platform, which defines a standard HOL theory and API that aims to be compatible with all HOL systems. So far, HOL Light and hol90 have been adapted for conformance, and HOL Zero was originally developed to conform. In this paper we provide motivation for a platform, give an overview of the Common HOL Platform's theory and API components, and show how to adapt legacy systems. We also report on the platform's successful application in the hand-translation of a few thousand lines of source code from HOL Light to HOL Zero.

  19. The Creative Platform

    DEFF Research Database (Denmark)

    Byrge, Christian; Hansen, Søren

    whether you consider thirdgrade teaching, human-resource development, or radical new thinking in product development in a company. The Creative Platform was developed at Aalborg University through a series of research-and-development activities in collaboration with educational institutions and private......This book is about introducing more creativity into general educational courses and cross-disciplinary activities. It is directed toward teachers at all levels in the educational system, but the Creative Platform is a general model, and thus the creative process will fundamentally be the same...... companies. It is a project in which the goal is to make a hands-on approach to a knowledge perspective on enhancing creativity. The underlying ambition of the Creative Platform is to make it easier to promote creativity. At www.uka.aau.dk/The+Creative+Platform, you can find extra materials and instructions...

  20. Coupled elasticity-diffusion model for the effects of cytoskeleton deformation on cellular uptake of cylindrical nanoparticles.

    Science.gov (United States)

    Wang, Jizeng; Li, Long

    2015-01-06

    Molecular dynamic simulations and experiments have recently demonstrated how cylindrical nanoparticles (CNPs) with large aspect ratios penetrate animal cells and inevitably deform cytoskeletons. Thus, a coupled elasticity-diffusion model was adopted to elucidate this interesting biological phenomenon by considering the effects of elastic deformations of cytoskeleton and membrane, ligand-receptor binding and receptor diffusion. The mechanism by which the binding energy drives the CNPs with different orientations to enter host cells was explored. This mechanism involved overcoming the resistance caused by cytoskeleton and membrane deformations and the change in configurational entropy of the ligand-receptor bonds and free receptors. Results showed that deformation of the cytoskeleton significantly influenced the engulfing process by effectively slowing down and even hindering the entry of the CNPs. Additionally, the engulfing depth was determined quantitatively. CNPs preferred or tended to vertically attack target cells until they were stuck in the cytoskeleton as implied by the speed of vertically oriented CNPs that showed much faster initial engulfing speeds than horizontally oriented CNPs. These results elucidated the most recent molecular dynamics simulations and experimental observations on the cellular uptake of carbon nanotubes and phagocytosis of filamentous Escherichia coli bacteria. The most efficient engulfment showed the stiffness-dependent optimal radius of the CNPs. Cytoskeleton stiffness exhibited more significant influence on the optimal sizes of the vertical uptake than the horizontal uptake. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  1. Association of membrane/lipid rafts with the platelet cytoskeleton and the caveolin PY14: participation in the adhesion process.

    Science.gov (United States)

    Cerecedo, Doris; Martínez-Vieyra, Ivette; Maldonado-García, Deneb; Hernández-González, Enrique; Winder, Steve J

    2015-11-01

    Platelets are the most prominent elements of blood tissue involved in hemostasis at sites of blood vessel injury. Platelet cytoskeleton is responsible for their shape modifications observed during activation and adhesion to the substratum; therefore the interactions between cytoskeleton and plasma membrane are critical to modulate blood platelet functions. Several cytoskeletal components and binding partners, as well as enzymes that regulate the cytoskeleton, localize to membrane/lipid rafts (MLR) and regulate lateral diffusion of membrane proteins and lipids. Resting, thrombin-activated, and adherent human platelets were processed for biochemical studies including western-blot and immunprecipitation assays and confocal analysis were performed to characterize the interaction of MLR with the main cytoskeleton elements and β-dystroglycan as well as with the association of caveolin-1 PY14 with focal adhesion proteins. We transfected a megakaryoblast cell line (Meg-01) to deplete β-dystroglycan, subsequent to their differentiation to the platelet progenitors. Our data showed a direct interaction of the MLR with cytoskeleton to regulate platelet shape, while an association of caveolin-1 PY14 with vinculin is needed to establish focal adhesions, which are modulated for β-dystroglycan. In conclusion, caveolin-1 PY14 in association with platelet cytoskeleton participate in focal adhesions dynamics.

  2. National Community Solar Platform

    Energy Technology Data Exchange (ETDEWEB)

    Rupert, Bart [Clean Energy Collective, Louisville, CO (United States)

    2016-06-30

    This project was created to provide a National Community Solar Platform (NCSP) portal known as Community Solar Hub, that is available to any entity or individual who wants to develop community solar. This has been done by providing a comprehensive portal to make CEC’s solutions, and other proven community solar solutions, externally available for everyone to access – making the process easy through proven platforms to protect subscribers, developers and utilities. The successful completion of this project provides these tools via a web platform and integration APIs, a wide spectrum of community solar projects included in the platform, multiple groups of customers (utilities, EPCs, and advocates) using the platform to develop community solar, and open access to anyone interested in community solar. CEC’s Incubator project includes web-based informational resources, integrated systems for project information and billing systems, and engagement with customers and users by community solar experts. The combined effort externalizes much of Clean Energy Collective’s industry-leading expertise, allowing third parties to develop community solar without duplicating expensive start-up efforts. The availability of this platform creates community solar projects that are cheaper to build and cheaper to participate in, furthering the goals of DOE’s SunShot Initiative. Final SF 425 Final SF 428 Final DOE F 2050.11 Final Report Narrative

  3. Modeling and simulation of luminescence detection platforms.

    Science.gov (United States)

    Salama, Khaled; Eltoukhy, Helmy; Hassibi, Arjang; El-Gamal, Abbas

    2004-06-15

    Motivated by the design of an integrated CMOS-based detection platform, a simulation model for CCD and CMOS imager-based luminescence detection systems is developed. The model comprises four parts. The first portion models the process of photon flux generation from luminescence probes using ATP-based and luciferase label-based assay kinetics. An optics simulator is then used to compute the incident photon flux on the imaging plane for a given photon flux and system geometry. Subsequently, the output image is computed using a detailed imaging sensor model that accounts for photodetector spectral response, dark current, conversion gain, and various noise sources. Finally, signal processing algorithms are applied to the image to enhance detection reliability and hence increase the overall system throughput. To validate the model, simulation results are compared to experimental results obtained from a CCD-based system that was built to emulate the integrated CMOS-based platform.

  4. The Platformization of the Web: Making Web Data Platform Ready

    NARCIS (Netherlands)

    A. Helmond

    2015-01-01

    In this article, I inquire into Facebook’s development as a platform by situating it within the transformation of social network sites into social media platforms. I explore this shift with a historical perspective on, what I refer to as, platformization, or the rise of the platform as the dominant

  5. Platform Performance and Challenges - using Platforms in Lego Company

    DEFF Research Database (Denmark)

    Munk, Lone; Mortensen, Niels Henrik

    2009-01-01

    by the product defining users (product developers) and platform erosion. When the platforms are not used it is due to: unsuitable calculation models, lack of goals, rewards or benefits from management, unattractive tradeoffs and difficulties in understanding the platform. This indicates that platform design...... needs focus on the incentive of using the platform. This problem lacks attention in literature, as well as industry, where assessment criteria do not cover this aspect. Therefore, we recommend including user incentive in platform assessment criteria to these challenges. Concrete solution elements...... ensuring user incentive in platforms is an object for future research...

  6. Properties of Ultrasound Probes

    OpenAIRE

    Rusina, M.

    2015-01-01

    This work deals with the measurement properties of ultrasound probes. Ultrasound probes and their parameters significantly affect the quality of the final image. In this work there are described the possibility of measuring the spatial resolution, sensitivity of the probe and measuring the length of the dead zone. Ultrasound phantom ATS Multi Purpose Phantom Type 539 was used for measurements.

  7. Transactional Network Platform: Applications

    Energy Technology Data Exchange (ETDEWEB)

    Katipamula, Srinivas; Lutes, Robert G.; Ngo, Hung; Underhill, Ronald M.

    2013-10-31

    In FY13, Pacific Northwest National Laboratory (PNNL) with funding from the Department of Energy’s (DOE’s) Building Technologies Office (BTO) designed, prototyped and tested a transactional network platform to support energy, operational and financial transactions between any networked entities (equipment, organizations, buildings, grid, etc.). Initially, in FY13, the concept demonstrated transactions between packaged rooftop air conditioners and heat pump units (RTUs) and the electric grid using applications or "agents" that reside on the platform, on the equipment, on a local building controller or in the Cloud. The transactional network project is a multi-lab effort with Oakridge National Laboratory (ORNL) and Lawrence Berkeley National Laboratory (LBNL) also contributing to the effort. PNNL coordinated the project and also was responsible for the development of the transactional network (TN) platform and three different applications associated with RTUs. This document describes two applications or "agents" in details, and also summarizes the platform. The TN platform details are described in another companion document.

  8. Identification of platform levels

    DEFF Research Database (Denmark)

    Mortensen, Niels Henrik

    2005-01-01

    reduction, ability to launch a wider product portfolio without increasing resources and reduction of complexity within the whole company. To support the multiple product development process, platform based product development has in many companies such as Philips, VW, Ford etc. proven to be a very effective...... because the nature of developing platforms and applications are very different. In single product development reuse is often determined by individual designers, in multiple product development reuse is to a large degree a management issue. It is difficult for a company to switch from single to multiple...... development will be examined. Based on the identification of the above characteristics five platform levels are described. The research presented in this paper is a result of MSc, Ph.D projects at the Technical University of Denmark and consultancy projects within the organisation of Institute of Product...

  9. Universal visualization platform

    Science.gov (United States)

    Gee, Alexander G.; Li, Hongli; Yu, Min; Smrtic, Mary Beth; Cvek, Urska; Goodell, Howie; Gupta, Vivek; Lawrence, Christine; Zhou, Jainping; Chiang, Chih-Hung; Grinstein, Georges G.

    2005-03-01

    Although there are a number of visualization systems to choose from when analyzing data, only a few of these allow for the integration of other visualization and analysis techniques. There are even fewer visualization toolkits and frameworks from which one can develop ones own visualization applications. Even within the research community, scientists either use what they can from the available tools or start from scratch to define a program in which they are able to develop new or modified visualization techniques and analysis algorithms. Presented here is a new general-purpose platform for constructing numerous visualization and analysis applications. The focus of this system is the design and experimentation of new techniques, and where the sharing of and integration with other tools becomes second nature. Moreover, this platform supports multiple large data sets, and the recording and visualizing of user sessions. Here we introduce the Universal Visualization Platform (UVP) as a modern data visualization and analysis system.

  10. Geostationary multipurpose platforms

    Science.gov (United States)

    Bekey, I.; Bowman, R. M.

    1981-01-01

    In addition to the advantages generally associated with orbital platforms, such as improved reliability, economies of scale, simple connectivity of elements, reduced tracking demands and the restraint of orbital object population growth, geostationary platforms yield: (1) continuous access by fixed ground antennas for communications services; (2) continuous monitoring of phenomena over chosen regions of the earth's surface; (3) a preferred location for many solar-terrestrial physics experiments. The geostationary platform also offers a low-risk and economical solution to the impending saturation of the orbital arc/frequency spectrum, maximizing the capacity of individual slots and increasing the utility of the entire arc. It also allows the use of many small, simple and inexpensive earth stations through complexity inversion and high power per beam. Block diagram and operational flowcharts are provided.

  11. Platforms for antibiotic discovery.

    Science.gov (United States)

    Lewis, Kim

    2013-05-01

    The spread of resistant bacteria, leading to untreatable infections, is a major public health threat but the pace of antibiotic discovery to combat these pathogens has slowed down. Most antibiotics were originally isolated by screening soil-derived actinomycetes during the golden era of antibiotic discovery in the 1940s to 1960s. However, diminishing returns from this discovery platform led to its collapse, and efforts to create a new platform based on target-focused screening of large libraries of synthetic compounds failed, in part owing to the lack of penetration of such compounds through the bacterial envelope. This article considers strategies to re-establish viable platforms for antibiotic discovery. These include investigating untapped natural product sources such as uncultured bacteria, establishing rules of compound penetration to enable the development of synthetic antibiotics, developing species-specific antibiotics and identifying prodrugs that have the potential to eradicate dormant persisters, which are often responsible for hard-to-treat infections.

  12. Regulation of actin cytoskeleton architecture by Eps8 and Abi1

    Directory of Open Access Journals (Sweden)

    Miller Jeffrey R

    2005-10-01

    Full Text Available Abstract Background The actin cytoskeleton participates in many fundamental processes including the regulation of cell shape, motility, and adhesion. The remodeling of the actin cytoskeleton is dependent on actin binding proteins, which organize actin filaments into specific structures that allow them to perform various specialized functions. The Eps8 family of proteins is implicated in the regulation of actin cytoskeleton remodeling during cell migration, yet the precise mechanism by which Eps8 regulates actin organization and remodeling remains elusive. Results Here, we show that Eps8 promotes the assembly of actin rich filopodia-like structures and actin cables in cultured mammalian cells and Xenopus embryos, respectively. The morphology of actin structures induced by Eps8 was modulated by interactions with Abi1, which stimulated formation of actin cables in cultured cells and star-like structures in Xenopus. The actin stars observed in Xenopus animal cap cells assembled at the apical surface of epithelial cells in a Rac-independent manner and their formation was accompanied by recruitment of N-WASP, suggesting that the Eps8/Abi1 complex is capable of regulating the localization and/or activity of actin nucleators. We also found that Eps8 recruits Dishevelled to the plasma membrane and actin filaments suggesting that Eps8 might participate in non-canonical Wnt/Polarity signaling. Consistent with this idea, mis-expression of Eps8 in dorsal regions of Xenopus embryos resulted in gastrulation defects. Conclusion Together, these results suggest that Eps8 plays multiple roles in modulating actin filament organization, possibly through its interaction with distinct sets of actin regulatory complexes. Furthermore, the finding that Eps8 interacts with Dsh and induced gastrulation defects provides evidence that Eps8 might participate in non-canonical Wnt signaling to control cell movements during vertebrate development.

  13. The plant actin cytoskeleton responds to signals from microbe-associated molecular patterns.

    Directory of Open Access Journals (Sweden)

    Jessica L Henty-Ridilla

    Full Text Available Plants are constantly exposed to a large and diverse array of microbes; however, most plants are immune to the majority of potential invaders and susceptible to only a small subset of pathogens. The cytoskeleton comprises a dynamic intracellular framework that responds rapidly to biotic stresses and supports numerous fundamental cellular processes including vesicle trafficking, endocytosis and the spatial distribution of organelles and protein complexes. For years, the actin cytoskeleton has been assumed to play a role in plant innate immunity against fungi and oomycetes, based largely on static images and pharmacological studies. To date, however, there is little evidence that the host-cell actin cytoskeleton participates in responses to phytopathogenic bacteria. Here, we quantified the spatiotemporal changes in host-cell cytoskeletal architecture during the immune response to pathogenic and non-pathogenic strains of Pseudomonas syringae pv. tomato DC3000. Two distinct changes to host cytoskeletal arrays were observed that correspond to distinct phases of plant-bacterial interactions i.e. the perception of microbe-associated molecular patterns (MAMPs during pattern-triggered immunity (PTI and perturbations by effector proteins during effector-triggered susceptibility (ETS. We demonstrate that an immediate increase in actin filament abundance is a conserved and novel component of PTI. Notably, treatment of leaves with a MAMP peptide mimic was sufficient to elicit a rapid change in actin organization in epidermal cells, and this actin response required the host-cell MAMP receptor kinase complex, including FLS2, BAK1 and BIK1. Finally, we found that actin polymerization is necessary for the increase in actin filament density and that blocking this increase with the actin-disrupting drug latrunculin B leads to enhanced susceptibility of host plants to pathogenic and non-pathogenic bacteria.

  14. Windows Azure Platform

    CERN Document Server

    Redkar, Tejaswi

    2011-01-01

    The Windows Azure Platform has rapidly established itself as one of the most sophisticated cloud computing platforms available. With Microsoft working to continually update their product and keep it at the cutting edge, the future looks bright - if you have the skills to harness it. In particular, new features such as remote desktop access, dynamic content caching and secure content delivery using SSL make the latest version of Azure a more powerful solution than ever before. It's widely agreed that cloud computing has produced a paradigm shift in traditional architectural concepts by providin

  15. Windows Azure Platform

    CERN Document Server

    Redkar, Tejaswi

    2010-01-01

    The Azure Services Platform is a brand-new cloud-computing technology from Microsoft. It is composed of four core components-Windows Azure, .NET Services, SQL Services, and Live Services-each with a unique role in the functioning of your cloud service. It is the goal of this book to show you how to use these components, both separately and together, to build flawless cloud services. At its heart Windows Azure Platform is a down-to-earth, code-centric book. This book aims to show you precisely how the components are employed and to demonstrate the techniques and best practices you need to know

  16. Wireless sensor platform

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Pooran C.; Killough, Stephen M.; Kuruganti, Phani Teja

    2017-08-08

    A wireless sensor platform and methods of manufacture are provided. The platform involves providing a plurality of wireless sensors, where each of the sensors is fabricated on flexible substrates using printing techniques and low temperature curing. Each of the sensors can include planar sensor elements and planar antennas defined using the printing and curing. Further, each of the sensors can include a communications system configured to encode the data from the sensors into a spread spectrum code sequence that is transmitted to a central computer(s) for use in monitoring an area associated with the sensors.

  17. Mobile4D platform

    CSIR Research Space (South Africa)

    Botha, Adèle

    2010-05-01

    Full Text Available . It is a communication platform that has architecture for creating, deploying and managing services and applications by integrating voice, video and data across a range of IP and telecom communication networks. In 2007, Red Hat made a firm commitment... based on the Mobicents muni ations Platform brand. 2.1.5  Telco specific User‐Generated Services   A variety of communication network operators have started initiatives to address User- Generated Services for the Telecom domain. Some...

  18. Cytoskeleton and nuclear lamina affection in recessive osteogenesis imperfecta: A functional proteomics perspective.

    Science.gov (United States)

    Gagliardi, Assunta; Besio, Roberta; Carnemolla, Chiara; Landi, Claudia; Armini, Alessandro; Aglan, Mona; Otaify, Ghada; Temtamy, Samia A; Forlino, Antonella; Bini, Luca; Bianchi, Laura

    2017-09-07

    Osteogenesis imperfecta (OI) is a collagen-related disorder associated to dominant, recessive or X-linked transmission, mainly caused by mutations in type I collagen genes or in genes involved in type I collagen metabolism. Among the recessive forms, OI types VII, VIII, and IX are due to mutations in CRTAP, P3H1, and PPIB genes, respectively. They code for the three components of the endoplasmic reticulum complex that catalyzes 3-hydroxylation of type I collagen α1Pro986. Under-hydroxylation of this residue leads to collagen structural abnormalities and results in moderate to lethal OI phenotype, despite the exact molecular mechanisms are still not completely clear. To shed light on these recessive forms, primary fibroblasts from OI patients with mutations in CRTAP (n=3), P3H1 (n=3), PPIB (n=1) genes and from controls (n=4) were investigated by a functional proteomic approach. Cytoskeleton and nucleoskeleton asset, protein fate, and metabolism were delineated as mainly affected. While western blot experiments confirmed altered expression of lamin A/C and cofilin-1, immunofluorescence analysis using antibody against lamin A/C and phalloidin showed an aberrant organization of nucleus and cytoskeleton. This is the first report describing an altered organization of intracellular structural proteins in recessive OI and pointing them as possible novel target for OI treatment. OI is a prototype for skeletal dysplasias. It is a highly heterogeneous collagen-related disorder with dominant, recessive and X-linked transmission. There is no definitive cure for this disease, thus a better understanding of the molecular basis of its pathophysiology is expected to contribute in identifying potential targets to develop new treatments. Based on this concept, we performed a functional proteomic study to delineate affected molecular pathways in primary fibroblasts from recessive OI patients, carrying mutations in CRTAP (OI type VII), P3H1 (OI type VIII), and PPIB (OI type IX) genes

  19. Beta adrenergic overstimulation impaired vascular contractility via actin-cytoskeleton disorganization in rabbit cerebral artery.

    Directory of Open Access Journals (Sweden)

    Hyoung Kyu Kim

    Full Text Available BACKGROUND AND PURPOSE: Beta adrenergic overstimulation may increase the vascular damage and stroke. However, the underlying mechanisms of beta adrenergic overstimulation in cerebrovascular dysfunctions are not well known. We investigated the possible cerebrovascular dysfunction response to isoproterenol induced beta-adrenergic overstimulation (ISO in rabbit cerebral arteries (CAs. METHODS: ISO was induced in six weeks aged male New Zealand white rabbit (0.8-1.0 kg by 7-days isoproterenol injection (300 μg/kg/day. We investigated the alteration of protein expression in ISO treated CAs using 2DE proteomics and western blot analysis. Systemic properties of 2DE proteomics result were analyzed using bioinformatics software. ROS generation and following DNA damage were assessed to evaluate deteriorative effect of ISO on CAs. Intracellular Ca(2+ level change and vascular contractile response to vasoactive drug, angiotensin II (Ang II, were assessed to evaluate functional alteration of ISO treated CAs. Ang II-induced ROS generation was assessed to evaluated involvement of ROS generation in CA contractility. RESULTS: Proteomic analysis revealed remarkably decreased expression of cytoskeleton organizing proteins (e.g. actin related protein 1A and 2, α-actin, capping protein Z beta, and vimentin and anti-oxidative stress proteins (e.g. heat shock protein 9A and stress-induced-phosphoprotein 1 in ISO-CAs. As a cause of dysregulation of actin-cytoskeleton organization, we found decreased level of RhoA and ROCK1, which are major regulators of actin-cytoskeleton organization. As functional consequences of proteomic alteration, we found the decreased transient Ca(2+ efflux and constriction response to angiotensin II and high K(+ in ISO-CAs. ISO also increased basal ROS generation and induced oxidative damage in CA; however, it decreased the Ang II-induced ROS generation rate. These results indicate that ISO disrupted actin cytoskeleton proteome network

  20. Cytoskeleton in motion: the dynamics of keratin intermediate filaments in epithelia.

    Science.gov (United States)

    Windoffer, Reinhard; Beil, Michael; Magin, Thomas M; Leube, Rudolf E

    2011-09-05

    Epithelia are exposed to multiple forms of stress. Keratin intermediate filaments are abundant in epithelia and form cytoskeletal networks that contribute to cell type-specific functions, such as adhesion, migration, and metabolism. A perpetual keratin filament turnover cycle supports these functions. This multistep process keeps the cytoskeleton in motion, facilitating rapid and protein biosynthesis-independent network remodeling while maintaining an intact network. The current challenge is to unravel the molecular mechanisms underlying the regulation of the keratin cycle in relation to actin and microtubule networks and in the context of epithelial tissue function.

  1. Compact Nanowire Sensors Probe Microdroplets.

    Science.gov (United States)

    Schütt, Julian; Ibarlucea, Bergoi; Illing, Rico; Zörgiebel, Felix; Pregl, Sebastian; Nozaki, Daijiro; Weber, Walter M; Mikolajick, Thomas; Baraban, Larysa; Cuniberti, Gianaurelio

    2016-08-10

    The conjunction of miniature nanosensors and droplet-based microfluidic systems conceptually opens a new route toward sensitive, optics-less analysis of biochemical processes with high throughput, where a single device can be employed for probing of thousands of independent reactors. Here we combine droplet microfluidics with the compact silicon nanowire based field effect transistor (SiNW FET) for in-flow electrical detection of aqueous droplets one by one. We chemically probe the content of numerous (∼10(4)) droplets as independent events and resolve the pH values and ionic strengths of the encapsulated solution, resulting in a change of the source-drain current ISD through the nanowires. Further, we discuss the specificities of emulsion sensing using ion sensitive FETs and study the effect of droplet sizes with respect to the sensor area, as well as its role on the ability to sense the interior of the aqueous reservoir. Finally, we demonstrate the capability of the novel droplets based nanowire platform for bioassay applications and carry out a glucose oxidase (GOx) enzymatic test for glucose detection, providing also the reference readout with an integrated parallel optical detector.

  2. FAM83H and casein kinase I regulate the organization of the keratin cytoskeleton and formation of desmosomes

    Science.gov (United States)

    Kuga, Takahisa; Sasaki, Mitsuho; Mikami, Toshinari; Miake, Yasuo; Adachi, Jun; Shimizu, Maiko; Saito, Youhei; Koura, Minako; Takeda, Yasunori; Matsuda, Junichiro; Tomonaga, Takeshi; Nakayama, Yuji

    2016-01-01

    FAM83H is essential for the formation of dental enamel because a mutation in the FAM83H gene causes amelogenesis imperfecta (AI). We previously reported that the overexpression of FAM83H often occurs and disorganizes the keratin cytoskeleton in colorectal cancer cells. We herein show that FAM83H regulates the organization of the keratin cytoskeleton and maintains the formation of desmosomes in ameloblastoma cells. FAM83H is expressed and localized on keratin filaments in human ameloblastoma cell lines and in mouse ameloblasts and epidermal germinative cells in vivo. FAM83H shows preferential localization to keratin filaments around the nucleus that often extend to cell-cell junctions. Alterations in the function of FAM83H by its overexpression, knockdown, or an AI-causing truncated mutant prevent the proper organization of the keratin cytoskeleton in ameloblastoma cells. Furthermore, the AI-causing mutant prevents desmosomal proteins from being localized to cell-cell junctions. The effects of the AI-causing mutant depend on its binding to and possible inhibition of casein kinase I (CK-1). The suppression of CK-1 by its inhibitor, D4476, disorganizes the keratin cytoskeleton. Our results suggest that AI caused by the FAM83H mutation is mediated by the disorganization of the keratin cytoskeleton and subsequent disruption of desmosomes in ameloblasts. PMID:27222304

  3. Local pulsatile contractions are an intrinsic property of the myosin 2A motor in the cortical cytoskeleton of adherent cells

    Science.gov (United States)

    Baird, Michelle A.; Billington, Neil; Wang, Aibing; Adelstein, Robert S.; Sellers, James R.; Fischer, Robert S.; Waterman, Clare M.

    2017-01-01

    The role of nonmuscle myosin 2 (NM2) pulsatile dynamics in generating contractile forces required for developmental morphogenesis has been characterized, but whether these pulsatile contractions are an intrinsic property of all actomyosin networks is not known. Here we used live-cell fluorescence imaging to show that transient, local assembly of NM2A “pulses” occurs in the cortical cytoskeleton of single adherent cells of mesenchymal, epithelial, and sarcoma origin, independent of developmental signaling cues and cell–cell or cell–ECM interactions. We show that pulses in the cortical cytoskeleton require Rho-associated kinase– or myosin light chain kinase (MLCK) activity, increases in cytosolic calcium, and NM2 ATPase activity. Surprisingly, we find that cortical cytoskeleton pulses specifically require the head domain of NM2A, as they do not occur with either NM2B or a 2B-head-2A-tail chimera. Our results thus suggest that pulsatile contractions in the cortical cytoskeleton are an intrinsic property of the NM2A motor that may mediate its role in homeostatic maintenance of tension in the cortical cytoskeleton of adherent cells. PMID:27881665

  4. Ion Implantation Hampers Pollen Tube Growth and Disrupts Actin Cytoskeleton Organization in Pollen Tubes of Pinus thunbergii

    Institute of Scientific and Technical Information of China (English)

    LI Guoping; HUANG Qunce; YANG Lusheng; QIN Guangyong

    2008-01-01

    Pollen grains of Pinus thunbergii Parl. (Japanese black pine) were implanted with 30 keV nitrogen ion beams and the effects of nitrogen ion implantation on pollen tube growth in vitro and the organization of actin cytoskeleton in the pollen tube cell were investigated using a confocal laser scanning microscope after fluorescence labeling. Treatment with ion implanta-tion significantly blocked pollen tube growth. Confocal microscopy showed that ion implantation disrupted actin filament cytoskeleton organization in the pollen tube. It was found that there was a distinct correlation between the inhibition of pollen tube growth and the disruption of actin cytoskeleton organization, indicating that an intact actin cytoskeleton is essential for con-tinuous pollen tube elongation in Pinus thunbergii. Although the detailed mechanism for the ion-implantation-induced bioeffect still remains to be elucidated, the present study assumes that the cytoskeleton system in pollen grains may provide a key target in response to ion beam im-plantation and is involved in mediating certain subsequent cytological changes.

  5. Games and Platform Decisions

    DEFF Research Database (Denmark)

    Hansen, Poul H. Kyvsgård; Mikkola, Juliana Hsuan

    2007-01-01

    is the application of on-line games in order to provide training for decision makers and in order to generate overview over the implications of platform decisions. However, games have to be placed in a context with other methods and we argue that a mixture of games, workshops, and simulations can provide improved...

  6. Creative Platform Learning (CPL)

    DEFF Research Database (Denmark)

    Christensen, Jonna Langeland; Hansen, Søren

    Creative Platform Learning (CPL) er en pædagogisk metode, der skaber foretagsomme og innovative elever, der kan anvende deres kreativitet til at lære nyt. Ifølge den nye skolereform skal Innovation og entreprenørskab tydeliggøres i alle fag. I CPL er det en integreret del af undervisningen...

  7. Games and Platform Decisions

    DEFF Research Database (Denmark)

    Hansen, Poul H. Kyvsgård; Mikkola, Juliana Hsuan

    2007-01-01

    is the application of on-line games in order to provide training for decision makers and in order to generate overview over the implications of platform decisions. However, games have to be placed in a context with other methods and we argue that a mixture of games, workshops, and simulations can provide improved...

  8. Arabidopsis CAP regulates the actin cytoskeleton necessary for plant cell elongation and division.

    Science.gov (United States)

    Barrero, Roberto A; Umeda, Masaaki; Yamamura, Saburo; Uchimiya, Hirofumi

    2002-01-01

    An Arabidopsis cDNA (AtCAP1) that encodes a predicted protein of 476 amino acids highly homologous with the yeast cyclase-associated protein (CAP) was isolated. Expression of AtCAP1 in the budding yeast CAP mutant was able to rescue defects such as abnormal cell morphology and random budding pattern. The C-terminal domain, 158 amino acids of AtCAP1 possessing in vitro actin binding activity, was needed for the regulation of cytoskeleton-related defects of yeast. Transgenic plants overexpressing AtCAP1 under the regulation of a glucocorticoid-inducible promoter showed different levels of AtCAP1 accumulation related to the extent of growth abnormalities, in particular size reduction of leaves as well as petioles. Morphological alterations in leaves were attributable to decreased cell size and cell number in both epidermal and mesophyll cells. Tobacco suspension-cultured cells (Bright Yellow 2) overexpressing AtCAP1 exhibited defects in actin filaments and were unable to undergo mitosis. Furthermore, an immunoprecipitation experiment suggested that AtCAP1 interacted with actin in vivo. Therefore, AtCAP1 may play a functional role in actin cytoskeleton networking that is essential for proper cell elongation and division.

  9. Impact of Simulated Microgravity on Cytoskeleton and Viscoelastic Properties of Endothelial Cell

    Science.gov (United States)

    Janmaleki, M.; Pachenari, M.; Seyedpour, S. M.; Shahghadami, R.; Sanati-Nezhad, A.

    2016-01-01

    This study focused on the effects of simulated microgravity (s-μg) on mechanical properties, major cytoskeleton biopolymers, and morphology of endothelial cells (ECs). The structural and functional integrity of ECs are vital to regulate vascular homeostasis and prevent atherosclerosis. Furthermore, these highly gravity sensitive cells play a key role in pathogenesis of many diseases. In this research, impacts of s-μg on mechanical behavior of human umbilical vein endothelial cells were investigated by utilizing a three-dimensional random positioning machine (3D-RPM). Results revealed a considerable drop in cell stiffness and viscosity after 24 hrs of being subjected to weightlessness. Cortical rigidity experienced relatively immediate and significant decline comparing to the stiffness of whole cell body. The cells became rounded in morphology while western blot analysis showed reduction of the main cytoskeletal components. Moreover, fluorescence staining confirmed disorganization of both actin filaments and microtubules (MTs). The results were compared statistically among test and control groups and it was concluded that s-μg led to a significant alteration in mechanical behavior of ECs due to remodeling of cell cytoskeleton. PMID:27581365

  10. Identification of Dynamic Changes in Proteins Associated with the Cellular Cytoskeleton after Exposure to Okadaic Acid

    Directory of Open Access Journals (Sweden)

    Peter Roepstorff

    2013-05-01

    Full Text Available Exposure of cells to the diarrhetic shellfish poison, okadaic acid, leads to a dramatic reorganization of cytoskeletal architecture and loss of cell-cell contact. When cells are exposed to high concentrations of okadaic acid (100–500 nM, the morphological rearrangement is followed by apoptotic cell death. Okadaic acid inhibits the broad acting Ser/Thr protein phosphatases 1 and 2A, which results in hyperphosphorylation of a large number of proteins. Some of these hyperphosphorylated proteins are most likely key players in the reorganization of the cell morphology induced by okadaic acid. We wanted to identify these phosphoproteins and searched for them in the cellular lipid rafts, which have been found to contain proteins that regulate cytoskeletal dynamics and cell adhesion. By using stable isotope labeling by amino acids in cell culture cells treated with okadaic acid (400 nM could be combined with control cells before the isolation of lipid rafts. Protein phosphorylation events and translocations induced by okadaic acid were identified by mass spectrometry. Okadaic acid was shown to regulate the phosphorylation status and location of proteins associated with the actin cytoskeleton, microtubules and cell adhesion structures. A large number of these okadaic acid-regulated proteins have previously also been shown to be similarly regulated prior to cell proliferation and migration. Our results suggest that okadaic acid activates general cell signaling pathways that induce breakdown of the cortical actin cytoskeleton and cell detachment.

  11. Epiplasmins and epiplasm in paramecium: the building of a submembraneous cytoskeleton.

    Science.gov (United States)

    Aubusson-Fleury, Anne; Bricheux, Geneviève; Damaj, Raghida; Lemullois, Michel; Coffe, Gérard; Donnadieu, Florence; Koll, France; Viguès, Bernard; Bouchard, Philippe

    2013-07-01

    In ciliates, basal bodies and associated appendages are bound to a submembrane cytoskeleton. In Paramecium, this cytoskeleton takes the form of a thin dense layer, the epiplasm, segmented into regular territories, the units where basal bodies are inserted. Epiplasmins, the main component of the epiplasm, constitute a large family of 51 proteins distributed in 5 phylogenetic groups, each characterized by a specific molecular design. By GFP-tagging, we analyzed their differential localisation and role in epiplasm building and demonstrated that: 1) The epiplasmins display a low turnover, in agreement with the maintenance of an epiplasm layer throughout the cell cycle; 2) Regionalisation of proteins from different groups allows us to define rim, core, ring and basal body epiplasmins in the interphase cell; 3) Their dynamics allows definition of early and late epiplasmins, detected early versus late in the duplication process of the units. Epiplasmins from each group exhibit a specific combination of properties. Core and rim epiplasmins are required to build a unit; ring and basal body epiplasmins seem more dispensable, suggesting that they are not required for basal body docking. We propose a model of epiplasm unit assembly highlighting its implication in structural heredity in agreement with the evolutionary history of epiplasmins.

  12. PLC-gamma1 and Rac1 coregulate EGF-induced cytoskeleton remodeling and cell migration.

    Science.gov (United States)

    Li, Siwei; Wang, Qian; Wang, Yi; Chen, Xinmei; Wang, Zhixiang

    2009-06-01

    It is well established that epidermal growth factor (EGF) induces the cytoskeleton reorganization and cell migration through two major signaling cascades: phospholipase C-gamma1 (PLC-gamma1) and Rho GTPases. However, little is known about the cross talk between PLC-gamma1 and Rho GTPases. Here we showed that PLC-gamma1 forms a complex with Rac1 in response to EGF. This interaction is direct and mediated by PLC-gamma1 Src homology 3 (SH3) domain and Rac1 (106)PNTP(109) motif. This interaction is critical for EGF-induced Rac1 activation in vivo, and PLC-gamma1 SH3 domain is actually a potent and specific Rac1 guanine nucleotide exchange factor in vitro. We have also demonstrated that the interaction between PLC-gamma1 SH3 domain and Rac1 play a significant role in EGF-induced F-actin formation and cell migration. We conclude that PLC-gamma1 and Rac1 coregulate EGF-induced cell cytoskeleton remodeling and cell migration by a direct functional interaction.

  13. The Actin Cytoskeleton in SMA and ALS: How Does It Contribute to Motoneuron Degeneration?

    Science.gov (United States)

    Hensel, Niko; Claus, Peter

    2017-04-01

    Amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA) are neurodegenerative diseases with overlapping clinical phenotypes based on impaired motoneuron function. However, the pathomechanisms of both diseases are largely unknown, and it is still unclear whether they converge on the molecular level. SMA is a monogenic disease caused by low levels of functional Survival of Motoneuron (SMN) protein, whereas ALS involves multiple genes as well as environmental factors. Recent evidence argues for involvement of actin regulation as a causative and dysregulated process in both diseases. ALS-causing mutations in the actin-binding protein profilin-1 as well as the ability of the SMN protein to directly bind to profilins argue in favor of a common molecular mechanism involving the actin cytoskeleton. Profilins are major regulators of actin-dynamics being involved in multiple neuronal motility and transport processes as well as modulation of synaptic functions that are impaired in models of both motoneuron diseases. In this article, we review the current literature in SMA and ALS research with a focus on the actin cytoskeleton. We propose a common molecular mechanism that explains the degeneration of motoneurons for SMA and some cases of ALS.

  14. On the role of the plasmodial cytoskeleton in facilitating intelligent behavior in slime mold Physarum polycephalum.

    Science.gov (United States)

    Mayne, Richard; Adamatzky, Andrew; Jones, Jeff

    2015-01-01

    The plasmodium of slime mold Physarum polycephalum behaves as an amorphous reaction-diffusion computing substrate and is capable of apparently 'intelligent' behavior. But how does intelligence emerge in an acellular organism? Through a range of laboratory experiments, we visualize the plasmodial cytoskeleton-a ubiquitous cellular protein scaffold whose functions are manifold and essential to life-and discuss its putative role as a network for transducing, transmitting and structuring data streams within the plasmodium. Through a range of computer modeling techniques, we demonstrate how emergent behavior, and hence computational intelligence, may occur in cytoskeletal communications networks. Specifically, we model the topology of both the actin and tubulin cytoskeletal networks and discuss how computation may occur therein. Furthermore, we present bespoke cellular automata and particle swarm models for the computational process within the cytoskeleton and observe the incidence of emergent patterns in both. Our work grants unique insight into the origins of natural intelligence; the results presented here are therefore readily transferable to the fields of natural computation, cell biology and biomedical science. We conclude by discussing how our results may alter our biological, computational and philosophical understanding of intelligence and consciousness.

  15. Stiffening of Red Blood Cells Induced by Cytoskeleton Disorders: A Joint Theory-Experiment Study.

    Science.gov (United States)

    Lai, Lipeng; Xu, Xiaofeng; Lim, Chwee Teck; Cao, Jianshu

    2015-12-01

    The functions and elasticities of the cell are largely related to the structures of the cytoskeletons underlying the lipid bilayer. Among various cell types, the red blood cell (RBC) possesses a relatively simple cytoskeletal structure. Underneath the membrane, the RBC cytoskeleton takes the form of a two-dimensional triangular network, consisting of nodes of actins (and other proteins) and edges of spectrins. Recent experiments focusing on the malaria-infected RBCs (iRBCs) show that there is a correlation between the elongation of spectrins in the cytoskeletal network and the stiffening of the iRBCs. Here we rationalize the correlation between these two observations by combining the wormlike chain model for single spectrins and the effective medium theory for the network elasticity. We specifically focus on how the disorders in the cytoskeletal network affect its macroscopic elasticity. Analytical and numerical solutions from our model reveal that the stiffness of the membrane increases with increasing end-to-end distances of spectrins, but has a nonmonotonic dependence on the variance of the end-to-end distance distributions. These predictions are verified quantitatively by our atomic force microscopy and micropipette aspiration measurements of iRBCs. The model may, from a molecular level, provide guidelines for future identification of new treatment methods for RBC-related diseases, such as malaria infection.

  16. Myeloperoxidase modulates human platelet aggregation via actin cytoskeleton reorganization and store-operated calcium entry

    Directory of Open Access Journals (Sweden)

    Irina V. Gorudko

    2013-07-01

    Myeloperoxidase (MPO is a heme-containing enzyme released from activated leukocytes into the extracellular space during inflammation. Its main function is the production of hypohalous acids that are potent oxidants. MPO can also modulate cell signaling and inflammatory responses independently of its enzymatic activity. Because MPO is regarded as an important risk factor for cardiovascular diseases associated with increased platelet activity, we studied the effects of MPO on human platelet functional properties. Laser scanning confocal microscopy was used to reveal carbohydrate-independent MPO binding to human platelet membrane. Adding MPO to platelets did not activate their aggregation under basal conditions (without agonist. In contrast, MPO augmented agonist-induced platelet aggregation, which was not prevented by MPO enzymatic activity inhibitors. It was found that exposure of platelets to MPO leads to actin cytoskeleton reorganization and an increase in their elasticity. Furthermore, MPO evoked a rise in cytosolic Ca2+ through enhancement of store-operated Ca2+ entry (SOCE. Together, these findings indicate that MPO is not a direct agonist but rather a mediator that binds to human platelets, induces actin cytoskeleton reorganization and affects the mechanical stiffness of human platelets, resulting in potentiating SOCE and agonist-induced human platelet aggregation. Therefore, an increased activity of platelets in vascular disease can, at least partly, be provided by MPO elevated concentrations.

  17. Cytoskeleton rearrangement induced by tetraspanin engagement modulates the activation of T and NK cells.

    Science.gov (United States)

    Crotta, Stefania; Ronconi, Vanessa; Ulivieri, Cristina; Baldari, Cosima T; Valiante, Nicholas M; Valiente, Nicholas M; Abrignani, Sergio; Wack, Andreas

    2006-04-01

    The hepatitis C virus (HCV) binds to human cells through the interaction of its envelope glycoprotein E2 with the tetraspanin CD81. We have previously reported that engagement of CD81 has opposite effects on T and NK cell function, as it enhances T cell receptor-mediated T cell activation and inhibits CD16- or IL-12-mediated NK cell activation. We further investigated this dichotomy and found that another tetraspanin, CD82, induces the same opposing effects on human primary T and NK cells. Activation by other unrelated stimuli such as NKG2D- and beta-1 integrin is also reduced by CD81 ligation on NK cells. CD81 engagement by monoclonal antibody or HCV-E2 enhances zeta and Erk phosphorylation in T cells and reduces them in NK cells, reflecting the opposite functional outcomes. CD81 engagement induces dramatic morphological changes and local F-actin accumulation in both NK and T cells, indicating rearrangement of the actin cytoskeleton. Pharmacological inhibition of actin polymerization reduces T cell activation, whereas it greatly enhances NK cell activation. Importantly, treatment with actin blockers abolishes the inhibitory effect of CD81 ligation on NK cells. We propose that tetraspanin engagement leads to comparable cytoskeleton reorganization in T and NK cells, which in turn results in opposite functional outcomes.

  18. Depolymerization of actin cytoskeleton is involved in stomatal closure-induced by extracellular calmodulin in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Extracellular calmodulin(CaM)plays significant roles in many physiological processes,but little is known about its mechanism of regulating stomatal movements.In this paper,whether CaM exists in the guard cell walls of Arabidopsis and whether depolymerization of actin cytoskeleton is involved in extracellular CaM-induced stomatal closing are investigated.It is found that CaM exists in guard cell walls of Arabidopsis,and its molecular weight is about 17 kD.Bioassay using CaM antagonists W7-agarose and anti-CaM serum shows that the endogenous extracellular CaM promotes stomatal closure and delays stomatal opening.The long radial actin filaments in guard cells undergo disruption in a time-dependent manner during exogenous CaM-induced stomatal closing.Pharmacological experiments show that depolymerization of actin cytoskeleton enhances the effect of exogenous CaM-induced stomatal closing and polymerization reduces the effect.We also find that exogenous CaM triggers an increase in [Ca2+]cyt of guard cells.If [Ca2+]cyt increase is blocked with EGTA,exogenous CaM-induced stomatal closure is inhibited.These results indicate that extracellular CaM causes elevation of [Ca2+]cyt in guard cells,subsequently resulting in disruption of actin filaments and finally leading to guard cells closure.

  19. Role of cytoskeleton in the mechanisms of stretch-induced cardiomyocytical hypertrophy in vitro

    Institute of Scientific and Technical Information of China (English)

    FENG Bing; QIN Jun; HE Zuo-yun; WANG De-wen

    2001-01-01

    To study in vitro the role of cytoskeleton in the mechanisms of stretch-induced cardiomyocyte hypertrophy. Methods: After cultured on a deformable membrane, the myocardial cells were incorporated with 3H-leucine (3H-leu) to determine the hypertrophic rate. The contents of angiotensin Ⅱ and endothelin in the supernatant of the culture medium were measured with radioimmunoassay. Results: Colchicine at 4 μmol/L partially inhibited 3H-leu incorporation rate of the stretch-induced cardiomyocytes but cytochalasin B showed no such effect. The radioactivity of 3H-leu incorporation in the supernatant of the culture medium was significantly lower in the cardiomyocyte culture treated with colchicines (4 μmol/L) or cytochalasin (0.4 μmol/L) than in simple myocardial cell culture. In addition, the 2 agents markedly inhibited the myocardial cells from secreting angiotensin Ⅱ and endothin. Conclusion: The cytoskeleton plays a role in the stretch-induced mycardiocyte hypertrophy by mediating the secretion of the cell growth factors by the cells themselves.

  20. MRP-1/CD9 gene transduction regulates the actin cytoskeleton through the downregulation of WAVE2.

    Science.gov (United States)

    Huang, C-L; Ueno, M; Liu, D; Masuya, D; Nakano, J; Yokomise, H; Nakagawa, T; Miyake, M

    2006-10-19

    Motility-related protein-1 (MRP-1/CD9) is involved in cell motility. We studied the change in the actin cytoskeleton, and the expression of actin-related protein (Arp) 2 and Arp3 and the Wiskott-Aldrich syndrome protein (WASP) family according to MRP-1/CD9 gene transduction into HT1080 cells. The frequency of cells with lamellipodia was significantly lower in MRP-1/CD9-transfected HT1080 cells than in control HT1080 cells (PMRP-1/CD9 gene transduction affected the subcellular localization of Arp2 and Arp3 proteins. Furthermore, MRP-1/CD9 gene transduction induced a downregulation of WAVE2 expression (PMRP-1/CD9 monoclonal antibody inhibited downregulation of WAVE2 in MRP-1/CD9-transfected HT1080 cells (PMRP-1/CD9 gene transduction. Furthermore, downregulation of WAVE2 by transfection of WAVE2-specific small interfering RNA (siRNA) mimicked the morphological effects of MRP-1/CD9 gene transduction and suppressed cell motility. However, transfection of each siRNA for Wnt1, Wnt2b1 or Wnt5a did not affect WAVE2 expression. Transfection of WAVE2-specific siRNA also did not affect expressions of these Wnts. These results indicate that MRP-1/CD9 regulates the actin cytoskeleton by downregulating of the WAVE2, through the Wnt-independent signal pathway.

  1. Cellular chirality arising from the self-organization of the actin cytoskeleton.

    Science.gov (United States)

    Tee, Yee Han; Shemesh, Tom; Thiagarajan, Visalatchi; Hariadi, Rizal Fajar; Anderson, Karen L; Page, Christopher; Volkmann, Niels; Hanein, Dorit; Sivaramakrishnan, Sivaraj; Kozlov, Michael M; Bershadsky, Alexander D

    2015-04-01

    Cellular mechanisms underlying the development of left-right asymmetry in tissues and embryos remain obscure. Here, the development of a chiral pattern of actomyosin was revealed by studying actin cytoskeleton self-organization in cells with isotropic circular shape. A radially symmetrical system of actin bundles consisting of α-actinin-enriched radial fibres (RFs) and myosin-IIA-enriched transverse fibres (TFs) evolved spontaneously into the chiral system as a result of the unidirectional tilting of all RFs, which was accompanied by a tangential shift in the retrograde movement of TFs. We showed that myosin-IIA-dependent contractile stresses within TFs drive their movement along RFs, which grow centripetally in a formin-dependent fashion. The handedness of the chiral pattern was shown to be regulated by α-actinin-1. Computational modelling demonstrated that the dynamics of the RF-TF system can explain the pattern transition from radial to chiral. Thus, actin cytoskeleton self-organization provides built-in machinery that potentially allows cells to develop left-right asymmetry.

  2. Aurora A kinase modulates actin cytoskeleton through phosphorylation of Cofilin: Implication in the mitotic process.

    Science.gov (United States)

    Ritchey, Lisa; Chakrabarti, Ratna

    2014-11-01

    Aurora A kinase regulates early mitotic events through phosphorylation and activation of a variety of proteins. Specifically, Aur-A is involved in centrosomal separation and formation of mitotic spindles in early prophase. The effect of Aur-A on mitotic spindles is mediated by the modulation of microtubule dynamics and association with microtubule binding proteins. In this study we show that Aur-A exerts its effects on spindle organization through the regulation of the actin cytoskeleton. Aurora A phosphorylates Cofilin at multiple sites including S(3) resulting in the inactivation of its actin depolymerizing function. Aur-A interacts with Cofilin in early mitotic phases and regulates its phosphorylation status. Cofilin phosphorylation follows a dynamic pattern during the progression of prophase to metaphase. Inhibition of Aur-A activity induced a delay in the progression of prophase to metaphase. Aur-A inhibitor also disturbed the pattern of Cofilin phosphorylation, which correlated with the mitotic delay. Our results establish a novel function of Aur-A in the regulation of actin cytoskeleton reorganization, through Cofilin phosphorylation during early mitotic stages.

  3. Formation of compact myelin is required for maturation of the axonal cytoskeleton

    Science.gov (United States)

    Brady, S. T.; Witt, A. S.; Kirkpatrick, L. L.; de Waegh, S. M.; Readhead, C.; Tu, P. H.; Lee, V. M.

    1999-01-01

    Although traditional roles ascribed to myelinating glial cells are structural and supportive, the importance of compact myelin for proper functioning of the nervous system can be inferred from mutations in myelin proteins and neuropathologies associated with loss of myelin. Myelinating Schwann cells are known to affect local properties of peripheral axons (de Waegh et al., 1992), but little is known about effects of oligodendrocytes on CNS axons. The shiverer mutant mouse has a deletion in the myelin basic protein gene that eliminates compact myelin in the CNS. In shiverer mice, both local axonal features like phosphorylation of cytoskeletal proteins and neuronal perikaryon functions like cytoskeletal gene expression are altered. This leads to changes in the organization and composition of the axonal cytoskeleton in shiverer unmyelinated axons relative to age-matched wild-type myelinated fibers, although connectivity and patterns of neuronal activity are comparable. Remarkably, transgenic shiverer mice with thin myelin sheaths display an intermediate phenotype indicating that CNS neurons are sensitive to myelin sheath thickness. These results indicate that formation of a normal compact myelin sheath is required for normal maturation of the neuronal cytoskeleton in large CNS neurons.

  4. Reorganization of microtubular cytoskeleton and formation of cellular processes during post-telophase in haemanthus endosperm.

    Science.gov (United States)

    Bajer, A S; Smirnova, E A

    1999-10-01

    We followed time-dependent post-telophase reorganization of the microtubule cytoskeleton on immunostained preparations of endosperm of the higher plant Haemanthus. After completion of mitosis, the phragmoplast continued to reorganize for several hours. This prompted the formation of phragmoplast-like derivatives (secondary and accessory phragmoplasts and peripheral microtubular ring). Next, elongated cellular protrusions (processes) appeared at the cell periphery. These processes contained long microtubule bundles and disorderly arranged actin filaments. Microtubule converging centers or accessory phragmoplasts were often present at the tips of the processes. Observation in vivo demonstrated that processes were formed at the cell periphery as extensions of lammelipodia or filopodia-type protrusions that commonly terminated with cytoplasmic blobs. We suggest that processes are derivatives of a peripheral microtubular ring that reorganizes gradually into cellular protrusions. Endosperm processes have several features of neuronal cells, or animal somatic cells with overexpressed MAPs. Since microtubule-containing processes were never detected shortly after extrusion of the cells from the embryo sac, this course of events might be restricted specifically to extruded endosperm and triggered either by removal of cells, their placement in monolayer on agar substrate, or both. Thus, post telophase behavior of endosperm cells offers a novel experimental system for studies of cytoskeleton in higher plants.

  5. Cytoskeleton-dependent endomembrane organization in plant cells: an emerging role for microtubules.

    Science.gov (United States)

    Brandizzi, Federica; Wasteneys, Geoffrey O

    2013-07-01

    Movement of secretory organelles is a fascinating yet largely mysterious feature of eukaryotic cells. Microtubule-based endomembrane and organelle motility utilizing the motor proteins dynein and kinesin is commonplace in animal cells. In contrast, it has been long accepted that intracellular motility in plant cells is predominantly driven by myosin motors dragging organelles and endomembrane-bounded cargo along actin filament bundles. Consistent with this, defects in the acto-myosin cytoskeleton compromise plant growth and development. Recent findings, however, challenge the actin-centric view of the motility of critical secretory organelles and distribution of associated protein machinery. In this review, we provide an overview of the current knowledge on actin-mediated organelle movement within the secretory pathway of plant cells, and report on recent and exciting findings that support a critical role of microtubules in plant cell development, in fine-tuning the positioning of Golgi stacks, as well as their involvement in cellulose synthesis and auxin polar transport. These emerging aspects of the biology of microtubules highlight adaptations of an ancestral machinery that plants have specifically evolved to support the functioning of the acto-myosin cytoskeleton, and mark new trends in our global appreciation of the complexity of organelle movement within the plant secretory pathway.

  6. Inositol induces mesenchymal-epithelial reversion in breast cancer cells through cytoskeleton rearrangement.

    Science.gov (United States)

    Dinicola, Simona; Fabrizi, Gianmarco; Masiello, Maria Grazia; Proietti, Sara; Palombo, Alessandro; Minini, Mirko; Harrath, Abdel Halim; Alwasel, Saleh H; Ricci, Giulia; Catizone, Angela; Cucina, Alessandra; Bizzarri, Mariano

    2016-07-01

    Inositol displays multi-targeted effects on many biochemical pathways involved in epithelial-mesenchymal transition (EMT). As Akt activation is inhibited by inositol, we investigated if such effect could hamper EMT in MDA-MB-231 breast cancer cells. In cancer cells treated with pharmacological doses of inositol E-cadherin was increased, β-catenin was redistributed behind cell membrane, and metalloproteinase-9 was significantly reduced, while motility and invading capacity were severely inhibited. Those changes were associated with a significant down-regulation of PI3K/Akt activity, leading to a decrease in downstream signaling effectors: NF-kB, COX-2, and SNAI1. Inositol-mediated inhibition of PS1 leads to lowered Notch 1 release, thus contributing in decreasing SNAI1 levels. Overall, these data indicated that inositol inhibits the principal molecular pathway supporting EMT. Similar results were obtained in ZR-75, a highly metastatic breast cancer line. These findings are coupled with significant changes on cytoskeleton. Inositol slowed-down vimentin expression in cells placed behind the wound-healing edge and stabilized cortical F-actin. Moreover, lamellipodia and filopodia, two specific membrane extensions enabling cell migration and invasiveness, were no longer detectable after inositol addiction. Additionally, fascin and cofilin, two mandatory required components for F-actin assembling within cell protrusions, were highly reduced. These data suggest that inositol may induce an EMT reversion in breast cancer cells, suppressing motility and invasiveness through cytoskeleton modifications.

  7. Stiffening of Red Blood Cells Induced by Cytoskeleton Disorders: A Joint Theory-Experiment Study

    Science.gov (United States)

    Lai, Lipeng; Xu, Xiaofeng; Lim, Chwee Teck; Cao, Jianshu

    2015-12-01

    The functions and elasticities of the cell are largely related to the structures of the cytoskeletons underlying the lipid bi-layer. Among various cell types, the Red Blood Cell (RBC) possesses a relatively simple cytoskeletal structure. Underneath the membrane, the RBC cytoskeleton takes the form of a two dimensional triangular network, consisting of nodes of actins (and other proteins) and edges of spectrins. Recent experiments focusing on the malaria infected RBCs (iRBCs) showed that there is a correlation between the elongation of spectrins in the cytoskeletal network and the stiffening of the iRBCs. Here we rationalize the correlation between these two observations by combining the worm-like chain (WLC) model for single spectrins and the Effective Medium Theory (EMT) for the network elasticity. We specifically focus on how the disorders in the cytoskeletal network affect its macroscopic elasticity. Analytical and numerical solutions from our model reveal that the stiffness of the membrane increases with increasing end-to-end distances of spectrins, but has a non-monotonic dependence on the variance of the end-to-end distance distributions. These predictions are verified quantitively by our AFM and micropipette aspiration measurements of iRBCs. The model may, from a molecular level, provide guidelines for future identification of new treatment methods for RBC related diseases, such as malaria infection.

  8. HGF Modulates Actin Cytoskeleton Remodeling and Contraction in Testicular Myoid Cells

    Directory of Open Access Journals (Sweden)

    Angela Catizone

    2015-01-01

    Full Text Available The presence of the HGF/Met system in the testicular myoid cells was first discovered by our group. However, the physiological role of this pathway remains poorly understood. We previously reported that HGF increases uPA secretion and TGF-β activation in cultured tubular fragments and that HGF is maximally expressed at Stages VII–VIII of the seminiferous epithelium cycle, when myoid cell contraction occurs. It is well known that the HGF/Met pathway is involved in cytoskeletal remodeling; moreover, the interaction of uPA with its receptor, uPAR, as well as the activation of TGF-β have been reported to be related to the actin cytoskeleton contractility of smooth muscle cells. Herein, we report that HGF induces actin cytoskeleton remodeling in vitro in isolated myoid cells and myoid cell contraction in cultured seminiferous tubules. To better understand these phenomena, we evaluated: (1 the regulation of the uPA machinery in isolated myoid cells after HGF administration; and (2 the effect of uPA or Met inhibition on HGF-treated tubular fragments. Because uPA activates latent TGF-β, the secretion of this factor was also evaluated. We found that both uPA and TGF-β activation increase after HGF administration. In testicular tubular fragments, HGF-induced TGF-β activation and myoid cell contraction are abrogated by uPA or Met inhibitor administration.

  9. Mobile Platforms and Development Environments

    CERN Document Server

    Helal, Sumi; Li, Wengdong

    2012-01-01

    Mobile platform development has lately become a technological war zone with extremely dynamic and fluid movement, especially in the smart phone and tablet market space. This Synthesis lecture is a guide to the latest developments of the key mobile platforms that are shaping the mobile platform industry. The book covers the three currently dominant native platforms -- iOS, Android and Windows Phone -- along with the device-agnostic HTML5 mobile web platform. The lecture also covers location-based services (LBS) which can be considered as a platform in its own right. The lecture utilizes a sampl

  10. Neural probe design for reduced tissue encapsulation in CNS.

    Science.gov (United States)

    Seymour, John P; Kipke, Daryl R

    2007-09-01

    This study investigated relationships between a microscale neural probe's size and shape and its chronic reactive tissue response. Parylene-based probes were microfabricated with a thick shank (48 microm by 68 microm) and an integrated thin lateral platform (5 microm by 100 microm, either solid or one of three lattice sizes). Devices were implanted in rat cerebral cortex for 4 weeks before immunostaining for neurons, astrocytes, microglia, fibronectin, laminin, and neurofilament. While nonneuronal density (NND) generally increased and neuronal density decreased within 75 microm of a probe interface compared to unimplanted control regions, there were significant differential tissue responses within 25 microm of the platform's lateral edge compared to the shank. The NND in this region of the lateral edge was less than one-third of the corresponding region of the shank (129% and 425% increase, respectively). Moreover, neuronal density around the platform lateral edge was about one-third higher than at the shank (0.70 and 0.52 relative to control, respectively). Also, microglia reactivity and extracellular protein deposition was reduced at the lateral edge. There were no significant differences among platform designs. These results suggest that neural probe geometry is an important parameter for reducing chronic tissue encapsulation.

  11. Multimodal super-resolution optical microscopy visualizes the close connection between membrane and the cytoskeleton in liver sinusoidal endothelial cell fenestrations

    Science.gov (United States)

    Mönkemöller, Viola; Øie, Cristina; Hübner, Wolfgang; Huser, Thomas; McCourt, Peter

    2015-11-01

    Liver sinusoidal endothelial cells (LSECs) act as a filter between blood and the hepatocytes. LSECs are highly fenestrated cells; they contain transcellular pores with diameters between 50 to 200 nm. The small sizes of the fenestrae have so far prohibited any functional analysis with standard and advanced light microscopy techniques. Only the advent of super-resolution optical fluorescence microscopy now permits the recording of such small cellular structures. Here, we demonstrate the complementary use of two different super-resolution optical microscopy modalities, 3D structured illumination microscopy (3D-SIM) and single molecule localization microscopy in a common optical platform to obtain new insights into the association between the cytoskeleton and the plasma membrane that supports the formation of fenestrations. We applied 3D-SIM to multi-color stained LSECs to acquire highly resolved overviews of large sample areas. We then further increased the spatial resolution for imaging fenestrations by single molecule localization microscopy applied to select small locations of interest in the same sample on the same microscope setup. We optimized the use of fluorescent membrane stains for these imaging conditions. The combination of these techniques offers a unique opportunity to significantly improve studies of subcellular ultrastructures such as LSEC fenestrations.

  12. Atom probe crystallography

    National Research Council Canada - National Science Library

    Gault, Baptiste; Moody, Michael P; Cairney, Julie M; Ringer, Simon P

    2012-01-01

    This review addresses new developments in the emerging area of "atom probe crystallography", a materials characterization tool with the unique capacity to reveal both composition and crystallographic...

  13. A novel platform device for rodent echocardiography.

    Science.gov (United States)

    Kutschka, Ingo; Sheikh, Ahmad Y; Sista, Ramachandra; Hendry, Stephen L; Chun, Hyung J; Hoyt, Grant; Kutschka, Werner; Pelletier, Marc P; Quertermous, Tom; Wu, Joseph C; Robbins, Robert C

    2007-06-06

    Acquisition of echocardiographic data from rodents is subject to wide variability due to variations in technique. We hypothesize that a dedicated imaging platform can aid in standardization of technique and improve the quality of images obtained. We constructed a device consisting of a boom-mounted steel platform frame (25 x 35 x 3 cm) on which a transparent polyethylene membrane is mounted. The animal is placed onto the membrane and receives continual inhaled anesthesia via an integrated port. The membrane allows for probe positioning from beneath the animal to obtain standard echo-views in left lateral decubitus or prone positions. The frame can be set at any desired angle ranging from 0 to 360 degrees along either the long or short axis. Adult male Sprague-Dawley rats (n = 5) underwent echocardiography (General Electric, Vivid 7, 14 MHz) using the platform. The device allowed for optimal positioning of animals for a variety of standard echocardiographic measurements. Evaluations among all animals showed minimal variability between two different operators and time points. We tested the feasibility of the device for supporting the assessment of cardiac function in a disease model by evaluating a separate cohort of adult male spontaneously hypertensive rats (n = 5) that underwent left anterior descending coronary artery ligation. Serial echocardiography demonstrated statistically significant decreases of fractional shortening and ejection fraction (p rats. Future studies will focus on improving this technology to allow for standardized high-throughput echocardiographic analysis in small animal models of disease.

  14. The Prediction of Key Cytoskeleton Components Involved in Glomerular Diseases Based on a Protein-Protein Interaction Network.

    Directory of Open Access Journals (Sweden)

    Fangrui Ding

    Full Text Available Maintenance of the physiological morphologies of different types of cells and tissues is essential for the normal functioning of each system in the human body. Dynamic variations in cell and tissue morphologies depend on accurate adjustments of the cytoskeletal system. The cytoskeletal system in the glomerulus plays a key role in the normal process of kidney filtration. To enhance the understanding of the possible roles of the cytoskeleton in glomerular diseases, we constructed the Glomerular Cytoskeleton Network (GCNet, which shows the protein-protein interaction network in the glomerulus, and identified several possible key cytoskeletal components involved in glomerular diseases. In this study, genes/proteins annotated to the cytoskeleton were detected by Gene Ontology analysis, and glomerulus-enriched genes were selected from nine available glomerular expression datasets. Then, the GCNet was generated by combining these two sets of information. To predict the possible key cytoskeleton components in glomerular diseases, we then examined the common regulation of the genes in GCNet in the context of five glomerular diseases based on their transcriptomic data. As a result, twenty-one cytoskeleton components as potential candidate were highlighted for consistently down- or up-regulating in all five glomerular diseases. And then, these candidates were examined in relation to existing known glomerular diseases and genes to determine their possible functions and interactions. In addition, the mRNA levels of these candidates were also validated in a puromycin aminonucleoside(PAN induced rat nephropathy model and were also matched with existing Diabetic Nephropathy (DN transcriptomic data. As a result, there are 15 of 21 candidates in PAN induced nephropathy model were consistent with our predication and also 12 of 21 candidates were matched with differentially expressed genes in the DN transcriptomic data. By providing a novel interaction network and

  15. Energy-dependent uptake of benzo[a]pyrene and its cytoskeleton-dependent intracellular transport by the telluric fungus Fusarium solani.

    Science.gov (United States)

    Fayeulle, Antoine; Veignie, Etienne; Slomianny, Christian; Dewailly, Etienne; Munch, Jean-Charles; Rafin, Catherine

    2014-03-01

    In screening indigenous soil filamentous fungi for polycyclic aromatic hydrocarbons (PAHs) degradation, an isolate of the Fusarium solani was found to incorporate benzo[a]pyrene (BaP) into fungal hyphae before degradation and mineralization. The mechanisms involved in BaP uptake and intracellular transport remain unresolved. To address this, the incorporation of two PAHs, BaP, and phenanthrene (PHE) were studied in this fungus. The fungus incorporated more BaP into cells than PHE, despite the 400-fold higher aqueous solubility of PHE compared with BaP, indicating that PAH incorporation is not based on a simple diffusion mechanism. To identify the mechanism of BaP incorporation and transport, microscopic studies were undertaken with the fluorescence probes Congo Red, BODIPY®493/503, and FM®4-64, targeting different cell compartments respectively fungal cell walls, lipids, and endocytosis. The metabolic inhibitor sodium azide at 100 mM totally blocked BaP incorporation into fungal cells indicating an energy-requirement for PAH uptake into the mycelium. Cytochalasins also inhibited BaP uptake by the fungus and probably its intracellular transport into fungal hyphae. The perfect co-localization of BaP and BODIPY reveals that lipid bodies constitute the intracellular storage sites of BaP in F. solani. Our results demonstrate an energy-dependent uptake of BaP and its cytoskeleton-dependent intracellular transport by F. solani.

  16. Online stock trading platform

    Directory of Open Access Journals (Sweden)

    Ion LUNGU

    2006-01-01

    Full Text Available The Internet is the perfect tool that can assure the market’s transparency for any user who wants to trade on the stock market. The investor can have access to the market news, financial calendar or the press releases of the issuers. A good online trading platform also provides real-time intraday quotes, trading history and technical analysis giving the investor a clearer view of the supply and demand in the market. All this information provides the investor a good image of the market and encourages him to trade. This paper wishes to draft the pieces of an online trading platform and to analyze the impact of developing and implementing one in a brokerage firm.

  17. Available: motorised platform

    CERN Document Server

    The COMPASS collaboration

    2014-01-01

    The COMPASS collaboration would like to offer to a new owner the following useful and fully operational piece of equipment, which is due to be replaced with better adapted equipment.   Please contact Erwin Bielert (erwin.bielert@cern.ch or 160539) for further information.  Motorized platform (FOR FREE):   Fabricated by ACL (Alfredo Cardoso & Cia Ltd) in Portugal. The model number is MeXs 5-­‐30.  Specifications: 5 m wide, 1 m deep, adjustable height (1.5 m if folded). Maximum working floor height: 4 m. conforms to CERN regulations, number LV158. Type LD500, capacity 500 kg and weight 2000 kg.  If no interested party is found before December 2014, the platform will be thrown away.

  18. Common tester platform concept.

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, Michael James

    2008-05-01

    This report summarizes the results of a case study on the doctrine of a common tester platform, a concept of a standardized platform that can be applicable across the broad spectrum of testing requirements throughout the various stages of a weapons program, as well as across the various weapons programs. The common tester concept strives to define an affordable, next-generation design that will meet testing requirements with the flexibility to grow and expand; supporting the initial development stages of a weapons program through to the final production and surveillance stages. This report discusses a concept investing key leveraging technologies and operational concepts combined with prototype tester-development experiences and practical lessons learned gleaned from past weapons programs.

  19. OGC Collaborative Platform undercover

    Science.gov (United States)

    Buehler, G.; Arctur, D. K.; Bermudez, L. E.

    2012-12-01

    The mission of the Open Geospatial Consortium (OGC) is to serve as a global forum for the collaboration of developers and users of spatial data products and services, and to advance the development of international standards for geospatial interoperability. The OGC coordinates with over 400 institutions in the development of geospatial standards. OGC has a dedicated staff supported by a Collaborative Web Platform to enable sophisticated and successful coordination among its members. Since its origins in the early 1990s, the OGC Collaborative Web Platform has evolved organically to be the collaboration hub for standards development in the exchange of geospatial and related types of information, among a global network of thousands of technical, scientific and management professionals spanning numerous disparate application domains. This presentation describes the structure of this collaboration hub, the relationships enabled (both among and beyond OGC members), and how this network fits in a broader ecosystem of technology development and information standards organizations.

  20. Video analysis platform

    OpenAIRE

    FLORES, Pablo; Arias, Pablo; Lecumberry, Federico; Pardo, Álvaro

    2006-01-01

    In this article we present the Video Analysis Platform (VAP) which is an open source software framework for video analysis, processing and description. The main goals of VAP are: to provide a multiplatform system which allows the easy implementation of video algorithms, provide structures and algorithms for the segmentation of video data in its different levels of abstraction: shots, frames, objects, regions, etc, permit the generation and comparison of MPEG7-like descriptors, and develop tes...

  1. Cloud Robotics Platforms

    Directory of Open Access Journals (Sweden)

    Busra Koken

    2015-01-01

    Full Text Available Cloud robotics is a rapidly evolving field that allows robots to offload computation-intensive and storage-intensive jobs into the cloud. Robots are limited in terms of computational capacity, memory and storage. Cloud provides unlimited computation power, memory, storage and especially collaboration opportunity. Cloud-enabled robots are divided into two categories as standalone and networked robots. This article surveys cloud robotic platforms, standalone and networked robotic works such as grasping, simultaneous localization and mapping (SLAM and monitoring.

  2. HPC - Platforms Penta Chart

    Energy Technology Data Exchange (ETDEWEB)

    Trujillo, Angelina Michelle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-10-08

    Strategy, Planning, Acquiring- very large scale computing platforms come and go and planning for immensely scalable machines often precedes actual procurement by 3 years. Procurement can be another year or more. Integration- After Acquisition, machines must be integrated into the computing environments at LANL. Connection to scalable storage via large scale storage networking, assuring correct and secure operations. Management and Utilization – Ongoing operations, maintenance, and trouble shooting of the hardware and systems software at massive scale is required.

  3. IP Rights and Technological Platforms

    OpenAIRE

    Robert P. Merges

    2008-01-01

    This paper is about intellectual property rights (IPRs) and platform technologies. After a brief introduction explaining some basics of networks, standards and platforms, I turn to three policy issues. The first is the role of IP in what might be termed platform policies, the decisions by courts and regulators concerning whether and how to promote multi-party access to important digital platforms such as media player hardware, cell phones, PCs, and the like. I argue that for the most part the...

  4. "Platform switching": Serendipity

    Directory of Open Access Journals (Sweden)

    N Kalavathy

    2014-01-01

    Full Text Available Implant dentistry is the latest developing field in terms of clinical techniques, research, material science and oral rehabilitation. Extensive work is being done to improve the designing of implants in order to achieve better esthetics and function. The main drawback with respect to implant restoration is achieving good osseointegration along with satisfactory stress distribution, which in turn will improve the prognosis of implant prosthesis by reducing the crestal bone loss. Many concepts have been developed with reference to surface coating of implants, surgical techniques for implant placement, immediate and delayed loading, platform switching concept, etc. This article has made an attempt to review the concept of platform switching was in fact revealed accidentally due to the nonavailability of the abutment appropriate to the size of the implant placed. A few aspect of platform switching, an upcoming idea to reduce crestal bone loss have been covered. The various methods used for locating and preparing the data were done through textbooks, Google search and related articles.

  5. "Platform switching": serendipity.

    Science.gov (United States)

    Kalavathy, N; Sridevi, J; Gehlot, Roshni; Kumar, Santosh

    2014-01-01

    Implant dentistry is the latest developing field in terms of clinical techniques, research, material science and oral rehabilitation. Extensive work is being done to improve the designing of implants in order to achieve better esthetics and function. The main drawback with respect to implant restoration is achieving good osseointegration along with satisfactory stress distribution, which in turn will improve the prognosis of implant prosthesis by reducing the crestal bone loss. Many concepts have been developed with reference to surface coating of implants, surgical techniques for implant placement, immediate and delayed loading, platform switching concept, etc. This article has made an attempt to review the concept of platform switching was in fact revealed accidentally due to the nonavailability of the abutment appropriate to the size of the implant placed. A few aspect of platform switching, an upcoming idea to reduce crestal bone loss have been covered. The various methods used for locating and preparing the data were done through textbooks, Google search and related articles.

  6. The Prodiguer Messaging Platform

    Science.gov (United States)

    Denvil, S.; Greenslade, M. A.; Carenton, N.; Levavasseur, G.; Raciazek, J.

    2015-12-01

    CONVERGENCE is a French multi-partner national project designed to gather HPC and informatics expertise to innovate in the context of running French global climate models with differing grids and at differing resolutions. Efficient and reliable execution of these models and the management and dissemination of model output are some of the complexities that CONVERGENCE aims to resolve.At any one moment in time, researchers affiliated with the Institut Pierre Simon Laplace (IPSL) climate modeling group, are running hundreds of global climate simulations. These simulations execute upon a heterogeneous set of French High Performance Computing (HPC) environments. The IPSL's simulation execution runtime libIGCM (library for IPSL Global Climate Modeling group) has recently been enhanced so as to support hitherto impossible realtime use cases such as simulation monitoring, data publication, metrics collection, simulation control, visualizations … etc. At the core of this enhancement is Prodiguer: an AMQP (Advanced Message Queue Protocol) based event driven asynchronous distributed messaging platform. libIGCM now dispatches copious amounts of information, in the form of messages, to the platform for remote processing by Prodiguer software agents at IPSL servers in Paris. Such processing takes several forms: Persisting message content to database(s); Launching rollback jobs upon simulation failure; Notifying downstream applications; Automation of visualization pipelines; We will describe and/or demonstrate the platform's: Technical implementation; Inherent ease of scalability; Inherent adaptiveness in respect to supervising simulations; Web portal receiving simulation notifications in realtime.

  7. Probe into How to Use the Literature Retrieval & Delivery Platforms to Provide Information Service for Arab Research---Base on the Superstar Duxiu, Bailian and Chinese Discovery%利用文献检索平台为阿拉伯研究提供信息服务的对策探讨--以超星读秀、百链云和中文发现为例

    Institute of Scientific and Technical Information of China (English)

    张红燕; 来泽荣

    2015-01-01

    Since the implementation of the opening strategy of“One Belt and One Road”, the cooperation between Ningxia and Arab countries in the fields of economy and trade, culture, education, and science and technology, etc. is deeper and wider. Under such a background, Ningxia University established Chinese Research Institute of Arab. Based on the Superstar Duxiu, Bailian and Chinese Discovery, this paper probes into how to use the literature retrieval&delivery platforms to provide efficient, multi-channel and comprehensive literature information service for Arab research.%自我国“一带一路”对外开放战略实施以来,宁夏与阿拉伯国家在经贸、文化、教育和科技等领域的合作更加深入和广泛。在此背景下,宁夏大学成立了中国阿拉伯研究院。以超星读秀、百链云和中文发现为例,探讨了如何利用这些文献检索和传递服务平台,为阿拉伯研究提供高效率、多途径和全方位的文献信息服务。

  8. Platform computing powers enterprise grid

    CERN Multimedia

    2002-01-01

    Platform Computing, today announced that the Stanford Linear Accelerator Center is using Platform LSF 5, to carry out groundbreaking research into the origins of the universe. Platform LSF 5 will deliver the mammoth computing power that SLAC's Linear Accelerator needs to process the data associated with intense high-energy physics research (1 page).

  9. Effects of altered gravity on the cell cycle, actin cytoskeleton and proteome in Physarum polycephalum

    Science.gov (United States)

    He, Jie; Zhang, Xiaoxian; Gao, Yong; Li, Shuijie; Sun, Yeqing

    Some researchers suggest that the changes of cell cycle under the effect of microgravity may be associated with many serious adverse physiological changes. In the search for underlying mechanisms and possible new countermeasures, we used the slime mold Physarum polycephalum in which all the nuclei traverse the cell cycle in natural synchrony to study the effects of altered gravity on the cell cycle, actin cytoskeleton and proteome. In parallel, the cell cycle was analyzed in Physarum incubated (1) in altered gravity for 20 h, (2) in altered gravity for 40 h, (3) in altered gravity for 80 h, and (4) in ground controls. The cell cycle, the actin cytoskeleton, and proteome in the altered gravity and ground controls were examined. The results indicated that the duration of the G2 phase was lengthened 20 min in high aspect ratio vessel (HARV) for 20 h, and prolonged 2 h in altered gravity either for 40 h or for 80 h, whereas the duration of other phases in the cell cycle was unchanged with respect to the control. The microfilaments in G2 phase had a reduced number of fibers and a unique abnormal morphology in altered gravity for 40 h, whereas the microfilaments in other phases of cell cycle were unchanged when compared to controls. Employing classical two-dimensional electrophoresis (2-DE), we examined the effect of the altered gravity on P. polycephalum proteins. The increase in the duration of G2 phase in altered gravity for 40 h was accompanied by changes in the 2-DE protein profiles, over controls. Out of a total of 200 protein spots investigated in G2 phase, which were reproducible in repeated experiments, 72 protein spots were visually identified as specially expressed, and 11 proteins were up-regulated by 2-fold and 28 proteins were down-regulated by 2-fold over controls. Out of a total of three low-expressed proteins in G2 phase in altered gravity for 40 h, two proteins were unknown proteins, and one protein was spherulin 3b by MALDI-TOF mass spectrometry (MS

  10. The bacterial cytoskeleton modulates motility, type 3 secretion, and colonization in Salmonella.

    Directory of Open Access Journals (Sweden)

    David M Bulmer

    2012-01-01

    Full Text Available Although there have been great advances in our understanding of the bacterial cytoskeleton, major gaps remain in our knowledge of its importance to virulence. In this study we have explored the contribution of the bacterial cytoskeleton to the ability of Salmonella to express and assemble virulence factors and cause disease. The bacterial actin-like protein MreB polymerises into helical filaments and interacts with other cytoskeletal elements including MreC to control cell-shape. As mreB appears to be an essential gene, we have constructed a viable ΔmreC depletion mutant in Salmonella. Using a broad range of independent biochemical, fluorescence and phenotypic screens we provide evidence that the Salmonella pathogenicity island-1 type three secretion system (SPI1-T3SS and flagella systems are down-regulated in the absence of MreC. In contrast the SPI-2 T3SS appears to remain functional. The phenotypes have been further validated using a chemical genetic approach to disrupt the functionality of MreB. Although the fitness of ΔmreC is reduced in vivo, we observed that this defect does not completely abrogate the ability of Salmonella to cause disease systemically. By forcing on expression of flagella and SPI-1 T3SS in trans with the master regulators FlhDC and HilA, it is clear that the cytoskeleton is dispensable for the assembly of these structures but essential for their expression. As two-component systems are involved in sensing and adapting to environmental and cell surface signals, we have constructed and screened a panel of such mutants and identified the sensor kinase RcsC as a key phenotypic regulator in ΔmreC. Further genetic analysis revealed the importance of the Rcs two-component system in modulating the expression of these virulence factors. Collectively, these results suggest that expression of virulence genes might be directly coordinated with cytoskeletal integrity, and this regulation is mediated by the two-component system

  11. S-nitrosylation of cofilin-1 mediates estradiol-17β-stimulated endothelial cytoskeleton remodeling.

    Science.gov (United States)

    Zhang, Hong-hai; Lechuga, Thomas J; Tith, Tevy; Wang, Wen; Wing, Deborah A; Chen, Dong-bao

    2015-03-01

    Rapid nitric oxide (NO) production via endothelial NO synthase (eNOS) activation represents a major signaling pathway for the cardiovascular protective effects of estrogens; however, the pathways after NO biosynthesis that estrogens use to function remain largely unknown. Covalent adduction of a NO moiety to cysteines, termed S-nitrosylation (SNO), has emerged as a key route for NO to directly regulate protein function. Cofilin-1 (CFL1) is a small actin-binding protein essential for actin dynamics and cytoskeleton remodeling. Despite being identified as a major SNO protein in endothelial cells, whether SNO regulates CFL-1 function is unknown. We hypothesized that estradiol-17β (E2β) stimulates SNO of CFL1 via eNOS-derived NO and that E2β-induced SNO-CFL1 mediates cytoskeleton remodeling in endothelial cells. Point mutation studies determined Cys80 as the primary SNO site among the 4 cysteines (Cys39/80/139/147) in CFL1. Substitutions of Cys80 with Ala or Ser were used to prepare the SNO-mimetic/deficient (C80A/S) CFL1 mutants. Recombinant wild-type (wt) and mutant CFL1 proteins were prepared; their actin-severing activity was determined by real-time fluorescence imaging analysis. The activity of C80A CFL1 was enhanced to that of the constitutively active S3/A CFL1, whereas the other mutants had no effects. C80A/S mutations lowered Ser3 phosphorylation. Treatment with E2β increased filamentous (F)-actin and filopodium formation in endothelial cells, which were significantly reduced in cells overexpressing wt-CFL. Overexpression of C80A, but not C80S, CFL1 decreased basal F-actin and further suppressed E2β-induced F-actin and filopodium formation compared with wt-CFL1 overexpression. Thus, SNO(Cys80) of cofilin-1 via eNOS-derived NO provides a novel pathway for mediating estrogen-induced endothelial cell cytoskeleton remodeling.

  12. CAPZA1 modulates EMT by regulating actin cytoskeleton remodelling in hepatocellular carcinoma.

    Science.gov (United States)

    Huang, Deng; Cao, Li; Zheng, Shuguo

    2017-01-16

    Epithelial-mesenchymal transition (EMT) elicits dramatic changes, including cytoskeleton remodelling as well as changes in gene expression and cellular phenotypes. During this process, actin filament assembly plays an important role in maintaining the morphology and movement of tumour cells. Capping protein, a protein complex referred to as CapZ, is an actin-binding complex that can regulate actin cytoskeleton remodelling. CAPZA1 is the α1 subunit of this complex, and we hypothesized that CAPZA1 regulates EMT through the regulation of actin filaments assembly, thus reducing the metastatic ability of hepatocellular carcinoma (HCC) cells. Immunohistochemistry was used to detect CAPZA1 expression in 129 HCC tissues. Western blotting and qPCR were used to detect CAPZA1, EMT markers and EMT transcription factors in HCC cells. Transwell migration and invasion assays were performed to observe the migration and invasion of HCC cells. Cell Counting Kit-8 (CCK-8) was used to detect the proliferation of HCC cells. Immunoprecipitation was used to detect the interaction between CAPZA1 and actin filaments. Finally, a small animal magnetic resonance imager (MRI) was used to observe metastases in HCC cell xenografts in the liver. CAPZA1 expression levels were negatively correlated with the biological characteristics of primary HCC and patient prognosis. CAPZA1 expression was negatively correlated with the migration and invasion of HCC cells. CAPZA1 down regulation promoted the migration and invasion of HCC cells. Conversely, CAPZA1 overexpression significantly inhibited the migration and invasion of HCC cells. Moreover, CAPZA1 expression levels were correlated with the expression of the EMT markers E-cadherin, N-cadherin and Vimentin. Furthermore, the expression of Snail1 and ZEB1 were negatively correlated with CAPZA1 expression levels. Similarly, CAPZA1 significantly inhibited intrahepatic metastases of HCC cells in an orthotopic transplantation tumour model. CAPZA1 inhibits

  13. Probe suppression in conformal phased array

    CERN Document Server

    Singh, Hema; Neethu, P S

    2017-01-01

    This book considers a cylindrical phased array with microstrip patch antenna elements and half-wavelength dipole antenna elements. The effect of platform and mutual coupling effect is included in the analysis. The non-planar geometry is tackled by using Euler's transformation towards the calculation of array manifold. Results are presented for both conducting and dielectric cylinder. The optimal weights obtained are used to generate adapted pattern according to a given signal scenario. It is shown that array along with adaptive algorithm is able to cater to an arbitrary signal environment even when the platform effect and mutual coupling is taken into account. This book provides a step-by-step approach for analyzing the probe suppression in non-planar geometry. Its detailed illustrations and analysis will be a useful text for graduate and research students, scientists and engineers working in the area of phased arrays, low-observables and stealth technology.

  14. Cross-platform analysis of global microRNA expression technologies

    Directory of Open Access Journals (Sweden)

    Stead John DH

    2010-05-01

    Full Text Available Abstract Background Although analysis of microRNAs (miRNAs by DNA microarrays is gaining in popularity, these new technologies have not been adequately validated. We examined within and between platform reproducibility of four miRNA array technologies alongside TaqMan PCR arrays. Results Two distinct pools of reference materials were selected in order to maximize differences in miRNA content. Filtering for miRNA that yielded signal above background revealed 54 miRNA probes (matched by sequence across all platforms. Using this probeset as well as all probes that were present on an individual platform, within-platform analyses revealed Spearman correlations of >0.9 for most platforms. Comparing between platforms, rank analysis of the log ratios of the two reference pools also revealed high correlation (range 0.663-0.949. Spearman rank correlation and concordance correlation coefficients for miRNA arrays against TaqMan qRT-PCR arrays were similar for all of the technologies. Platform performances were similar to those of previous cross-platform exercises on mRNA and miRNA microarray technologies. Conclusions These data indicate that miRNA microarray platforms generated highly reproducible data and can be recommended for the study of changes in miRNA expression.

  15. Pioneer Jupiter orbiter probe mission 1980, probe description

    Science.gov (United States)

    Defrees, R. E.

    1974-01-01

    The adaptation of the Saturn-Uranus Atmospheric Entry Probe (SUAEP) to a Jupiter entry probe is summarized. This report is extracted from a comprehensive study of Jovian missions, atmospheric model definitions and probe subsystem alternatives.

  16. Creating and Probing Graphene Electron Optics with Local Scanning Probes

    Science.gov (United States)

    Stroscio, Joseph

    Ballistic propagation and the light-like dispersion of graphene charge carriers make graphene an attractive platform for optics-inspired graphene electronics where gate tunable potentials can control electron refraction and transmission. In analogy to optical wave propagation in lenses, mirrors and metamaterials, gate potentials can be used to create a negative index of refraction for Veselago lensing and Fabry-Pérot interferometers. In circular geometries, gate potentials can induce whispering gallery modes (WGM), similar to optical and acoustic whispering galleries albeit on a much smaller length scale. Klein scattering of Dirac carriers plays a central role in determining the coherent propagation of electron waves in these resonators. In this talk, I examine the probing of electron resonators in graphene confined by linear and circular gate potentials with the scanning tunneling microscope (STM). The tip in the STM tunnel junction serves both as a tunable local gate potential, and as a probe of the graphene states through tunneling spectroscopy. A combination of a back gate potential, Vg, and tip potential, Vb, creates and controls a circular pn junction that confines the WGM graphene states. The resonances are observed in two separate channels in the tunneling spectroscopy experiment: first, by directly tunneling into the state at the bias energy eVb, and, second, by tunneling from the resonance at the Fermi level as the state is gated by the tip potential. The second channel produces a fan-like set of WGM peaks, reminiscent of the fringes seen in planar geometries by transport measurements. The WGM resonances split in a small applied magnetic field, with a large energy splitting approaching the WGM spacing at 0.5 T. These results agree well with recent theory on Klein scattering in graphene electron resonators. This work is done in collaboration with Y. Zhao, J. Wyrick, F.D. Natterer, J. F. Rodriquez-Nieva, C. Lewandoswski, K. Watanabe, T. Taniguchi, N. B

  17. Nanoscale microwave microscopy using shielded cantilever probes

    KAUST Repository

    Lai, Keji

    2011-04-21

    Quantitative dielectric and conductivity mapping in the nanoscale is highly desirable for many research disciplines, but difficult to achieve through conventional transport or established microscopy techniques. Taking advantage of the micro-fabrication technology, we have developed cantilever-based near-field microwave probes with shielded structures. Sensitive microwave electronics and finite-element analysis modeling are also utilized for quantitative electrical imaging. The system is fully compatible with atomic force microscope platforms for convenient operation and easy integration of other modes and functions. The microscope is ideal for interdisciplinary research, with demonstrated examples in nano electronics, physics, material science, and biology.

  18. The cytoskeleton of chondrocytes of Sepia officinalis (Mollusca, Cephalopoda: an immunocytochemical study

    Directory of Open Access Journals (Sweden)

    F Leone

    2009-06-01

    Full Text Available Our previous electron microscope study showed that chondrocytes from cephalopod cartilage possess a highly developed cytoskeleton and numerous cytoplasmic processes that ramify extensively through the tissue. We have now carried out a light microscope immunocytochemical study of chondrocytes from the orbital cartilage of Sepia officinalis to obtain indications as to the nature of the cytoskeletal components. We found clear positivity to antibodies against mammalian tubulin, vimentin, GFAP, and actin, but not keratin. The simultaneous presence of several cytoskeletal components is consistent with the hypothesis that cephalopod chondrocytes have the characteristics of both chondrocytes and osteocytes of vertebrates, which endow the tissue as a whole with some of the properties of vertebrate bone. We confirm, therefore, the presence in molluscs of the ubiquitous cytoskeletal proteins of metazoan cells that have remained highly conserved throughout phylogenetic evolution.

  19. Uncivil engineers: Chlamydia, Salmonella and Shigella alter cytoskeleton architecture to invade epithelial cells.

    Science.gov (United States)

    Dunn, Joe Dan; Valdivia, Raphael H

    2010-08-01

    The obligate intracellular bacterial pathogen Chlamydia trachomatis is a major cause of blindness and sexually transmitted diseases. Like the enteric pathogens Salmonella and Shigella, Chlamydia injects effector proteins into epithelial cells to initiate extensive remodeling of the actin cytoskeleton at the bacterial attachment site, which culminates in the engulfment of the bacterium by plasma membrane extensions. Numerous Salmonella and Shigella effectors promote this remodeling by activating Rho GTPases and tyrosine kinase signaling cascades and by directly manipulating actin dynamics. Recent studies indicate that similar host-cell alterations occur during Chlamydia invasion, but few effectors are known. The identification of additional Chlamydia effectors and the elucidation of their modes of function are critical steps towards an understanding of how this clinically important pathogen breaches epithelial surfaces and causes infection.

  20. Live Cell Imaging Reveals Structural Associations between the Actin and Microtubule Cytoskeleton in Arabidopsis [W] [OA

    Science.gov (United States)

    Sampathkumar, Arun; Lindeboom, Jelmer J.; Debolt, Seth; Gutierrez, Ryan; Ehrhardt, David W.; Ketelaar, Tijs; Persson, Staffan

    2011-01-01

    In eukaryotic cells, the actin and microtubule (MT) cytoskeletal networks are dynamic structures that organize intracellular processes and facilitate their rapid reorganization. In plant cells, actin filaments (AFs) and MTs are essential for cell growth and morphogenesis. However, dynamic interactions between these two essential components in live cells have not been explored. Here, we use spinning-disc confocal microscopy to dissect interaction and cooperation between cortical AFs and MTs in Arabidopsis thaliana, utilizing fluorescent reporter constructs for both components. Quantitative analyses revealed altered AF dynamics associated with the positions and orientations of cortical MTs. Reorganization and reassembly of the AF array was dependent on the MTs following drug-induced depolymerization, whereby short AFs initially appeared colocalized with MTs, and displayed motility along MTs. We also observed that light-induced reorganization of MTs occurred in concert with changes in AF behavior. Our results indicate dynamic interaction between the cortical actin and MT cytoskeletons in interphase plant cells. PMID:21693695

  1. Orchestrating cytoskeleton and intracellular vesicle traffic to build functional immunological synapses.

    Science.gov (United States)

    Soares, Helena; Lasserre, Rémi; Alcover, Andrés

    2013-11-01

    Immunological synapses are specialized cell-cell contacts formed between T lymphocytes and antigen-presenting cells. They are induced upon antigen recognition and are crucial for T-cell activation and effector functions. The generation and function of immunological synapses depend on an active T-cell polarization process, which results from a finely orchestrated crosstalk between the antigen receptor signal transduction machinery, the actin and microtubule cytoskeletons, and controlled vesicle traffic. Although we understand how some of these particular events are regulated, we still lack knowledge on how these multiple cellular elements are harmonized to ensure appropriate T-cell responses. We discuss here our view on how T-cell receptor signal transduction initially commands cytoskeletal and vesicle traffic polarization, which in turn sets the immunological synapse molecular design that regulates T-cell activation. We also discuss how the human immunodeficiency virus (HIV-1) hijacks some of these processes impairing immunological synapse generation and function.

  2. Enhanced Labeling Techniques to Study the Cytoskeleton During Root Growth and Gravitropism

    Science.gov (United States)

    Blancaflor, Elison B.

    2005-01-01

    Gravity effects the growth and development of all living organisms. One of the most obvious manifestations of gravity's effects on biological systems lies in the ability of plants to direct their growth along a path that is dictated by the gravity vector (called gravitropism). When positioned horizontally, in florescence stems and hypocotyls in dicots, and pulvini in monocots, respond by bending upward whereas roots typically bend downward. Gravitropism allows plants to readjust their growth to maximize light absorption for photosynthesis and to more efficiently acquire water and nutrients form the soil. Despite its significance for plant survival, there are still major gaps in understanding the cellular and molecular processes by which plants respond to gravity. The major aim of this proposal was to develop improved fluorescence labeling techniques to aid in understanding how the cytoskeleton modulated plant responses to gravity.

  3. Interaction of hepatitis C virus F protein with prefoldin 2 perturbs tubulin cytoskeleton organization.

    Science.gov (United States)

    Tsao, Mei-Ling; Chao, Chung-Hao; Yeh, Chau-Ting

    2006-09-15

    By use of the yeast two-hybrid system, hepatitis C virus (HCV) F protein was found to interact with a cellular protein named prefoldin 2. The interaction was confirmed by confocal immunofluorescence microscopy as well as coimmunoprecipitation experiments. Prefoldin 2 is a subunit of a hexameric molecular chaperone complex, named prefoldin, which delivers nascent actin and tubulin proteins to the eukaryotic cytosolic chaperonin for facilitated folding. Functional prefoldin spontaneously assembles from its six subunits (prefoldin 1-6). In the yeast three-hybrid system, it was found that expression of HCV F protein impeded the interaction between prefoldin 1 and 2. By performing immunofluorescence experiment and non-denaturing gel electrophoresis, it was shown that expression of HCV F protein resulted in aberrant organization of tubulin cytoskeleton. Since HCV replication requires intact microtubule and actin polymerization, HCV F protein may serve as a modulator to prevent high level of HCV replication and thus contributes to viral persistence in chronic HCV infection.

  4. Crosstalk between the actin cytoskeleton and Ran-mediated nuclear transport

    Directory of Open Access Journals (Sweden)

    Steward Ruth

    2005-08-01

    Full Text Available Abstract Background Transport of macromolecules into and out of the nucleus is a highly regulated process. The RanGTP/RanGDP gradient controls the trafficking of molecules exceeding the diffusion limit of the nuclear pore across the nuclear envelope. Results We found genetic interaction between genes establishing the Ran gradient, nuclear transport factor 2 (ntf-2, Ran GTPase activating protein (Sd, and the gene encoding Drosophila Profilin, chickadee (chic. The severe eye phenotype caused by reduction of NTF2 is suppressed by loss of function mutations in chic and gain of function mutations in Sd (RanGAP. We show that in chic mutants, as in Sd-RanGAP, nuclear export is impaired. Conclusion Our data suggest that Profilin and the organization of the actin cytoskeleton play an important role in nuclear trafficking.

  5. The Role of Molecular Microtubule Motors and the Microtubule Cytoskeleton in Stress Granule Dynamics

    Directory of Open Access Journals (Sweden)

    Kristen M. Bartoli

    2011-01-01

    Full Text Available Stress granules (SGs are cytoplasmic foci that appear in cells exposed to stress-induced translational inhibition. SGs function as a triage center, where mRNAs are sorted for storage, degradation, and translation reinitiation. The underlying mechanisms of SGs dynamics are still being characterized, although many key players have been identified. The main components of SGs are stalled 48S preinitiation complexes. To date, many other proteins have also been found to localize in SGs and are hypothesized to function in SG dynamics. Most recently, the microtubule cytoskeleton and associated motor proteins have been demonstrated to function in SG dynamics. In this paper, we will discuss current literature examining the function of microtubules and the molecular microtubule motors in SG assembly, coalescence, movement, composition, organization, and disassembly.

  6. Maintenance of asymmetric cellular localization of an auxin transport protein through interaction with the actin cytoskeleton

    Science.gov (United States)

    Muday, G. K.

    2000-01-01

    In shoots, polar auxin transport is basipetal (that is, from the shoot apex toward the base) and is driven by the basal localization of the auxin efflux carrier complex. The focus of this article is to summarize the experiments that have examined how the asymmetric distribution of this protein complex is controlled and the significance of this polar distribution. Experimental evidence suggests that asymmetries in the auxin efflux carrier may be established through localized secretion of Golgi vesicles, whereas an attachment of a subunit of the efflux carrier to the actin cytoskeleton may maintain this localization. In addition, the idea that this localization of the efflux carrier may control both the polarity of auxin movement and more globally regulate developmental polarity is explored. Finally, evidence indicating that the gravity vector controls auxin transport polarity is summarized and possible mechanisms for the environmentally induced changes in auxin transport polarity are discussed.

  7. Growth cone travel in space and time: the cellular ensemble of cytoskeleton, adhesion, and membrane.

    Science.gov (United States)

    Vitriol, Eric A; Zheng, James Q

    2012-03-22

    Growth cones, found at the tip of axonal projections, are the sensory and motile organelles of developing neurons that enable axon pathfinding and target recognition for precise wiring of the neural circuitry. To date, many families of conserved guidance molecules and their corresponding receptors have been identified that work in space and time to ensure billions of axons to reach their targets. Research in the past two decades has also gained significant insight into the ways in which growth cones translate extracellular signals into directional migration. This review aims to examine new progress toward understanding the cellular mechanisms underlying directional motility of the growth cone and to discuss questions that remain to be addressed. Specifically, we will focus on the cellular ensemble of cytoskeleton, adhesion, and membrane and examine how the intricate interplay between these processes orchestrates the directed movement of growth cones.

  8. The role of the cytoskeleton in volume regulation and beading transitions in PC12 neurites

    CERN Document Server

    Fernandez, Pablo

    2010-01-01

    We present investigations on volume regulation and beading shape transitions in PC12 neurites conducted using a flow-chamber technique. By disrupting the cell cytoskeleton with specific drugs we investigate the role of its individual components in the volume regulation response. We find that microtubule disruption increases both swelling rate and maximum volume attained, but does not affect the ability of the neurite to recover its initial volume. In addition, investigation of axonal beading --also known as pearling instability-- provides additional clues on the mechanical state of the neurite. We conclude that the initial swelling phase is mechanically slowed down by microtubules, while the volume recovery is driven by passive diffusion of osmolites. Our experiments provide a framework to investigate the role of cytoskeletal mechanics in volume homeostasis.

  9. Plasma membrane and cytoskeleton dynamics during single-cell wound healing.

    Science.gov (United States)

    Boucher, Eric; Mandato, Craig A

    2015-10-01

    Wounding leads not only to plasma membrane disruption, but also to compromised cytoskeleton structures. This results not only in unwarranted exchanges between the cytosol and extracellular milieu, but also in loss of tensegrity, which may further endanger the cell. Tensegrity can be described as the interplay between the tensile forces generated by the apparent membrane tension, actomyosin contraction, and the cytoskeletal structures resisting those changes (e.g., microtubules). It is responsible for the structural integrity of the cell and for its ability to sense mechanical signals. Recent reviews dealing with single-cell healing mostly focused on the molecular machineries controlling the traffic and fusion of specific vesicles, or their role in different pathologies. In this review, we aim to take a broader view of the different modes of single cell repair, while focussing on the different ways the changes in plasmalemma surface area and composition, plasmalemma tension, and cytoskeletal dynamics may influence and affect single-cell repair.

  10. WIP modulates dendritic spine actin cytoskeleton by transcriptional control of lipid metabolic enzymes.

    Science.gov (United States)

    Franco-Villanueva, Ana; Fernández-López, Estefanía; Gabandé-Rodríguez, Enrique; Bañón-Rodríguez, Inmaculada; Esteban, Jose Antonio; Antón, Inés M; Ledesma, María Dolores

    2014-08-15

    We identify Wiskott-Aldrich syndrome protein (WASP)-interacting protein (WIP) as a novel component of neuronal synapses whose absence increases dendritic spine size and filamentous actin levels in an N-WASP/Arp2/3-independent, RhoA/ROCK/profilinIIa-dependent manner. These effects depend on the reduction of membrane sphingomyelin (SM) due to transcriptional upregulation of neutral sphingomyelinase (NSM) through active RhoA; this enhances RhoA binding to the membrane, raft partitioning and activation in steady state but prevents RhoA changes in response to stimulus. Inhibition of NSM or SM addition reverses RhoA, filamentous actin and functional anomalies in synapses lacking WIP. Our findings characterize WIP as a link between membrane lipid composition and actin cytoskeleton at dendritic spines. They also contribute to explain cognitive deficits shared by individuals bearing mutations in the region assigned to the gene encoding for WIP.

  11. Response of Cytoskeleton of Murine Osteoblast Cultures to Two-step Freezing

    Institute of Scientific and Technical Information of China (English)

    Bao-Lin LIU; John McGRATH

    2005-01-01

    Understanding the ultrastructural response of cells to the freezing process is important for designing cryopreservation strategies for cells and tissues. The cellular structures of attached cells are targets of cryopreservation-induced damage. Specific fluorescence staining was used to assess the status of the actin filaments (F-actin) of murine osteoblasts attached to hydroxyapatite discs and plastic coverslips for a two-step freezing process. The F-actin of dead cells was depolymerized and distorted in the freezing process,whereas that of live cells had little change. The results suggest that the cytoskeleton may support the robustness of cells during cryopreservation. The present study helps to investigate the damage mechanism of attached cells during the freezing process.

  12. Cytolethal Distending Toxin From Campylobacter jejuni Requires the Cytoskeleton for Toxic Activity

    Science.gov (United States)

    Méndez-Olvera, Estela T.; Bustos-Martínez, Jaime A.; López-Vidal, Yolanda; Verdugo-Rodríguez, Antonio; Martínez-Gómez, Daniel

    2016-01-01

    Background Campylobacter jejuni is one of the major causes of infectious diarrhea worldwide. The distending cytolethal toxin (CDT) of Campylobacter spp. interferes with normal cell cycle progression. This toxic effect is considered a result of DNase activity that produces chromosomal DNA damage. To perform this event, the toxin must be endocytosed and translocated to the nucleus. Objectives The aim of this study was to evaluate the role of the cytoskeleton in the translocation of CDT to the nucleus. Methods Campylobacter jejuni ATCC 33291 and seven isolates donated from Instituto de Biotecnologia were used in this study. The presence of CDT genes in C. jejuni strains was determined by PCR. To evaluate the effect of CDT, HeLa cells were treated with bacterial lysate, and the damage and morphological changes were analyzed by microscopy, immunofluorescence staining, and flow cytometry. To evaluate the role of the cytoskeleton, HeLa cells were treated with either latrunculin A or by nocodazole and analyzed by microscopy, flow cytometry, and immunoquantification (ELISA). Results The results obtained showed that the eight strains of C. jejuni, including the reference strain, had the ability to produce the toxin. Usage of latrunculin A and nocodazole, two cytoskeletal inhibitors, blocked the toxic effect in cells treated with the toxin. This phenomenon was evident in flow cytometry analysis and immunoquantification of Cdc2-phosphorylated. Conclusions This work showed that the cytotoxic activity of the C. jejuni CDT is dependent on its endocytosis. The alteration in the microtubules and actin filaments caused a blockage transit of the toxin, preventing it from reaching the nucleus of the cell, as well as preventing DNA fragmentation and alteration of the cell cycle. The CDT toxin appears to be an important element for the pathogenesis of campylobacteriosis, since all clinical isolates showed the presence of cdtA, cdtB and cdtC genes. PMID:27942359

  13. Ethanol exposure disrupts extraembryonic microtubule cytoskeleton and embryonic blastomere cell adhesion, producing epiboly and gastrulation defects

    Directory of Open Access Journals (Sweden)

    Swapnalee Sarmah

    2013-08-01

    Fetal alcohol spectrum disorder (FASD occurs when pregnant mothers consume alcohol, causing embryonic ethanol exposure and characteristic birth defects that include craniofacial, neural and cardiac defects. Gastrulation is a particularly sensitive developmental stage for teratogen exposure, and zebrafish is an outstanding model to study gastrulation and FASD. Epiboly (spreading blastomere cells over the yolk cell, prechordal plate migration and convergence/extension cell movements are sensitive to early ethanol exposure. Here, experiments are presented that characterize mechanisms of ethanol toxicity on epiboly and gastrulation. Epiboly mechanisms include blastomere radial intercalation cell movements and yolk cell microtubule cytoskeleton pulling the embryo to the vegetal pole. Both of these processes were disrupted by ethanol exposure. Ethanol effects on cell migration also indicated that cell adhesion was affected, which was confirmed by cell aggregation assays. E-cadherin cell adhesion molecule expression was not affected by ethanol exposure, but E-cadherin distribution, which controls epiboly and gastrulation, was changed. E-cadherin was redistributed into cytoplasmic aggregates in blastomeres and dramatically redistributed in the extraembryonic yolk cell. Gene expression microarray analysis was used to identify potential causative factors for early development defects, and expression of the cell adhesion molecule protocadherin-18a (pcdh18a, which controls epiboly, was significantly reduced in ethanol exposed embryos. Injecting pcdh18a synthetic mRNA in ethanol treated embryos partially rescued epiboly cell movements, including enveloping layer cell shape changes. Together, data show that epiboly and gastrulation defects induced by ethanol are multifactorial, and include yolk cell (extraembryonic tissue microtubule cytoskeleton disruption and blastomere adhesion defects, in part caused by reduced pcdh18a expression.

  14. Importance of Interaction between Integrin and Actin Cytoskeleton in Suspension Adaptation of CHO cells.

    Science.gov (United States)

    Walther, Christa G; Whitfield, Robert; James, David C

    2016-04-01

    The biopharmaceutical production process relies upon mammalian cell technology where single cells proliferate in suspension in a chemically defined synthetic environment. This environment lacks exogenous growth factors, usually contributing to proliferation of fibroblastic cell types such as Chinese hamster ovary (CHO) cells. Use of CHO cells for production hence requires a lengthy 'adaptation' process to select clones capable of proliferation as single cells in suspension. The underlying molecular changes permitting proliferation in suspension are not known. Comparison of the non-suspension-adapted clone CHO-AD and a suspension-adapted propriety cell line CHO-SA by flow cytometric analysis revealed a highly variable bi-modal expression pattern for cell-to-cell contact proteins in contrast to the expression pattern seen for integrins. Those have a uni-modal expression on suspension and adherent cells. Integrins showed a conformation distinguished by regularly distributed clusters forming a sphere on the cell membrane of suspension-adapted cells. Actin cytoskeleton analysis revealed reorganisation from the typical fibrillar morphology found in adherent cells to an enforced spherical subcortical actin sheath in suspension cells. The uni-modal expression and specific clustering of integrins could be confirmed for CHO-S, another suspension cell line. Cytochalasin D treatment resulted in breakdown of the actin sheath and the sphere-like integrin conformation demonstrating the link between integrins and actin in suspension-adapted CHO cells. The data demonstrates the importance of signalling changes, leading to an integrin rearrangement on the cell surface, and the necessity of the reinforcement of the actin cytoskeleton for proliferation in suspension conditions.

  15. The Drosophila planar polarity gene multiple wing hairs directly regulates the actin cytoskeleton.

    Science.gov (United States)

    Lu, Qiuheng; Schafer, Dorothy A; Adler, Paul N

    2015-07-15

    The evolutionarily conserved frizzled/starry night (fz/stan) pathway regulates planar cell polarity (PCP) in vertebrates and invertebrates. This pathway has been extensively studied in the Drosophila wing, where it is manifested by an array of distally pointing cuticular hairs. Using in vivo imaging we found that, early in hair growth, cells have multiple actin bundles and hairs that subsequently fuse into a single growing hair. The downstream PCP gene multiple wing hairs (mwh) plays a key role in this process and acts to antagonize the actin cytoskeleton. In mwh mutants hair initiation is not limited to a small region at the distal edge of pupal wing cells as in wild type, resulting in multiple hairs with aberrant polarity. Extra actin bundles/hairs are formed and do not completely fuse, in contrast to wild type. As development proceeded additional hairs continued to form, further increasing hair number. We identified a fragment of Mwh with in vivo rescue activity and that bound and bundled F-actin filaments and inhibited actin polymerization in in vitro actin assays. The loss of these activities can explain the mwh mutant phenotype. Our data suggest a model whereby, prior to hair initiation, proximally localized Mwh inhibits actin polymerization resulting in polarized activation of the cytoskeleton and hair formation on the distal side of wing cells. During hair growth Mwh is found in growing hairs, where we suggest it functions to promote the fusion of actin bundles and inhibit the formation of additional actin bundles that could lead to extra hairs.

  16. Effects of chondroitin sulfate on alteration of actin cytoskeleton in rats with acute necrotizing pancreatitis

    Institute of Scientific and Technical Information of China (English)

    Zhong-Ye He; Ren-Xuan Guo

    2007-01-01

    BACKGROUND: In experimental acute pancreatitis, a large amount of reactive oxygen species are produced, and in turn cytoskeletal changes may be induced in pancreatic tissue. These changes contribute to an imbalance of digestive enzyme segregation, transport, exocytosis and activation, resulting in cell injury. In this study, we assessed the effects of chondroitin sulfate (CS) on attenuation of oxidative damage and protection of F-actin in rats with acute necrotizing pancreatitis (ANP). METHODS:Ninety male Wistar rats were divided randomly into three groups. Group A was infused with 5% sodium taurocholate; group B was treated with CS;and group C served as control. Rats from the three groups were killed at 1, 3 or 8 hours. The levels were measured of malonyl dialdehyde (MDA), total superoxide dismutase (SOD), glutathione synthetase (GSH), serum amylase (SAM) and adenosine triphosphate (ATP). F-actin immunostained with rhodamine-phalloidin was analyzed using a confocal laser scanning system and the content of F-actin protein was determined. RESULTS: The levels of SAM increased in groups A and B, whereas the levels of GSH, SOD and ATP in group A decreased markedly during pancreatitis, and MDA increased signiifcantly. The levels of GSH, SOD and ATP in group B were higher than those in group A, but the level of MDA was lower than in group A. At the same time, ANP resulted in early disruption of the cytoskeleton with dramatic changes and a loss of F-actin. Administration of CS moderated the damage to the actin cytoskeleton. CONCLUSIONS:Retrograde infusion of sodium taurocholate via the pancreatic duct may produce pancreatic necrosis and a marked increase in serum amylase activity, induce a severe depletion of ATP level, prime lipid peroxidation, and damage F-actin. Treatment with CS can ameliorate pancreatic cell conditions, limit cell membrane peroxidation, protect F-actin, and attenuate pancreatitis.

  17. Rearrangements of microtubule cytoskeleton in stomatal closure of Arabidopsis induced by nitric oxide

    Institute of Scientific and Technical Information of China (English)

    ZHANG YongMei; WU ZhongYi; WANG XueChen; YU Rong

    2008-01-01

    NO (nitric oxide), known as a key signal molecule in plant, plays important roles in regulation of stomatal movement. In this study, microtubule dynamics and its possible mechanism in the NO signal pathway were investigated. The results were as follows: (ⅰ) In vivo stomatal aperture assays revealed that both vinblastine (microtubule-disrupting drug) and SNP (exogenous NO donor) prevented stomatal opening in the light, and vinblastine even could enhance the inhibitory effect of SNP, whereas taxol (a microtubule-stabilizing agent) was able to reduce this effect; (ⅱ) microtubules in the opening Arabi-dopsis guard cells expressing GFP:α-tubulin-6 (AtGFP:α-tubulin-6) were organized in parallel, straight and dense bundles, radiating from the ventral side to the dorsal side, and most of them were localized perpendicularly to the ventral wall; (ⅲ) under the same environmental conditions, treated with SNP for 30 min, the radial arrays of microtubules in guard cells began to break down, twisted partially and be-came oblique or exhibited a random pattern; (ⅳ) furthermore, the involvement of cytosolic Ca2+ in this event was tested. Stomatal aperture assays revealed that BAPTA-AM (a chelator of Ca2+) greatly sup-pressed the effect of NO on stomatal closure; however, it did not show the same function on stomatal closure induced by vinblastine. When BAPTA-AM was added to the SNP-pretreated solution, the SNP-induced disordered microtubulue cytoskeleton in guard cells underwent rearrangement in a time-dependent manner. After 30 min of treatment with BAPTA-AM, the cortical microtubules resumed the original radial distribution, almost the same as the control. All this indicates that NO may promote rearrangement of microtubule cytoskeleton via elevation of [Ca2+]cyt (free Ca2+ concentration in the cy-toplasm), finally leading to stomatal closure.

  18. Retinoids and glucocorticoids have opposite effects on actin cytoskeleton rearrangement in hippocampal HT22 cells.

    Science.gov (United States)

    Hélène, Roumes; Julie, Brossaud; Aloïs, Lemelletier; Marie-Pierre, Moisan; Véronique, Pallet; Anabelle, Redonnet; Jean-Benoît, Corcuff

    2016-02-01

    A chronic excess of glucocorticoids elicits deleterious effects in the hippocampus. Conversely, retinoic acid plays a major role in aging brain plasticity. As synaptic plasticity depends on mechanisms related to cell morphology, we investigated the involvement of retinoic acid and glucocorticoids in the remodelling of the HT22 neurons actin cytoskeleton. Cells exhibited a significantly more elongated shape with retinoic acid and a rounder shape with dexamethasone; retinoic acid reversed the effects of dexamethasone. Actin expression and abundance were unchanged by retinoic acid or dexamethasone but F-actin organization was dramatically modified. Indeed, retinoic acid and dexamethasone increased (70 ± 7% and 176 ± 5%) cortical actin while retinoic acid suppressed the effect of dexamethasone (90 ± 6%). Retinoic acid decreased (-22 ± 9%) and dexamethasone increased (134 ± 16%) actin stress fibres. Retinoic acid also suppressed the effect of dexamethasone (-21 ± 7%). Spectrin is a key protein in the actin network remodelling. Its abundance was decreased by retinoic acid and increased by dexamethasone (-21 ± 11% and 52 ± 10%). However, retinoic acid did not modify the effect of dexamethasone (48 ± 7%). Calpain activity on spectrin was increased by retinoic acid and decreased by dexamethasone (26 ± 14% and -57 ± 5%); retinoic acid mildly but significantly modified the effect of dexamethasone (-44 ± 7%). The calpain inhibitor calpeptin suppressed the effects of retinoic acid and dexamethasone on cell shape and actin stress fibres remodelling but did not modify the effects on cortical actin. Retinoic acid and dexamethasone have a dramatic but mainly opposite effect on actin cytoskeleton remodelling. These effects originate, at least partly, from calpain activity.

  19. Cell elasticity is regulated by the tropomyosin isoform composition of the actin cytoskeleton.

    Science.gov (United States)

    Jalilian, Iman; Heu, Celine; Cheng, Hong; Freittag, Hannah; Desouza, Melissa; Stehn, Justine R; Bryce, Nicole S; Whan, Renee M; Hardeman, Edna C; Fath, Thomas; Schevzov, Galina; Gunning, Peter W

    2015-01-01

    The actin cytoskeleton is the primary polymer system within cells responsible for regulating cellular stiffness. While various actin binding proteins regulate the organization and dynamics of the actin cytoskeleton, the proteins responsible for regulating the mechanical properties of cells are still not fully understood. In the present study, we have addressed the significance of the actin associated protein, tropomyosin (Tpm), in influencing the mechanical properties of cells. Tpms belong to a multi-gene family that form a co-polymer with actin filaments and differentially regulate actin filament stability, function and organization. Tpm isoform expression is highly regulated and together with the ability to sort to specific intracellular sites, result in the generation of distinct Tpm isoform-containing actin filament populations. Nanomechanical measurements conducted with an Atomic Force Microscope using indentation in Peak Force Tapping in indentation/ramping mode, demonstrated that Tpm impacts on cell stiffness and the observed effect occurred in a Tpm isoform-specific manner. Quantitative analysis of the cellular filamentous actin (F-actin) pool conducted both biochemically and with the use of a linear detection algorithm to evaluate actin structures revealed that an altered F-actin pool does not absolutely predict changes in cell stiffness. Inhibition of non-muscle myosin II revealed that intracellular tension generated by myosin II is required for the observed increase in cell stiffness. Lastly, we show that the observed increase in cell stiffness is partially recapitulated in vivo as detected in epididymal fat pads isolated from a Tpm3.1 transgenic mouse line. Together these data are consistent with a role for Tpm in regulating cell stiffness via the generation of specific populations of Tpm isoform-containing actin filaments.

  20. Effects of plasma membrane cholesterol level and cytoskeleton F-actin on cell protrusion mechanics.

    Directory of Open Access Journals (Sweden)

    Nima Khatibzadeh

    Full Text Available Protrusions are deformations that form at the surface of living cells during biological activities such as cell migration. Using combined optical tweezers and fluorescent microscopy, we quantified the mechanical properties of protrusions in adherent human embryonic kidney cells in response to application of an external force at the cell surface. The mechanical properties of protrusions were analyzed by obtaining the associated force-length plots during protrusion formation, and force relaxation at constant length. Protrusion mechanics were interpretable by a standard linear solid (Kelvin model, consisting of two stiffness parameters, k0 and k1 (with k0>k1, and a viscous coefficient. While both stiffness parameters contribute to the time-dependant mechanical behavior of the protrusions, k0 and k1 in particular dominated the early and late stages of the protrusion formation and elongation process, respectively. Lowering the membrane cholesterol content by 25% increased the k0 stiffness by 74%, and shortened the protrusion length by almost half. Enhancement of membrane cholesterol content by nearly two-fold increased the protrusion length by 30%, and decreased the k0 stiffness by nearly two-and-half-fold as compared with control cells. Cytoskeleton integrity was found to make a major contribution to protrusion mechanics as evidenced by the effects of F-actin disruption on the resulting mechanical parameters. Viscoelastic behavior of protrusions was further characterized by hysteresis and force relaxation after formation. The results of this study elucidate the coordination of plasma membrane composition and cytoskeleton during protrusion formation.

  1. Cytolethal Distending Toxin From Campylobacter jejuni Requires the Cytoskeleton for Toxic Activity.

    Science.gov (United States)

    Méndez-Olvera, Estela T; Bustos-Martínez, Jaime A; López-Vidal, Yolanda; Verdugo-Rodríguez, Antonio; Martínez-Gómez, Daniel

    2016-10-01

    Campylobacter jejuni is one of the major causes of infectious diarrhea worldwide. The distending cytolethal toxin (CDT) of Campylobacter spp. interferes with normal cell cycle progression. This toxic effect is considered a result of DNase activity that produces chromosomal DNA damage. To perform this event, the toxin must be endocytosed and translocated to the nucleus. The aim of this study was to evaluate the role of the cytoskeleton in the translocation of CDT to the nucleus. Campylobacter jejuni ATCC 33291 and seven isolates donated from Instituto de Biotecnologia were used in this study. The presence of CDT genes in C. jejuni strains was determined by PCR. To evaluate the effect of CDT, HeLa cells were treated with bacterial lysate, and the damage and morphological changes were analyzed by microscopy, immunofluorescence staining, and flow cytometry. To evaluate the role of the cytoskeleton, HeLa cells were treated with either latrunculin A or by nocodazole and analyzed by microscopy, flow cytometry, and immunoquantification (ELISA). The results obtained showed that the eight strains of C. jejuni, including the reference strain, had the ability to produce the toxin. Usage of latrunculin A and nocodazole, two cytoskeletal inhibitors, blocked the toxic effect in cells treated with the toxin. This phenomenon was evident in flow cytometry analysis and immunoquantification of Cdc2-phosphorylated. This work showed that the cytotoxic activity of the C. jejuni CDT is dependent on its endocytosis. The alteration in the microtubules and actin filaments caused a blockage transit of the toxin, preventing it from reaching the nucleus of the cell, as well as preventing DNA fragmentation and alteration of the cell cycle. The CDT toxin appears to be an important element for the pathogenesis of campylobacteriosis, since all clinical isolates showed the presence of cdtA, cdtB and cdtC genes.

  2. The Geohazards Exploitation Platform

    Science.gov (United States)

    Laur, Henri; Casu, Francesco; Bally, Philippe; Caumont, Hervé; Pinto, Salvatore

    2016-04-01

    The Geohazards Exploitation Platform, or Geohazards TEP (GEP), is an ESA originated R&D activity of the EO ground segment to demonstrate the benefit of new technologies for large scale processing of EO data. This encompasses on-demand processing for specific user needs, systematic processing to address common information needs of the geohazards community, and integration of newly developed processors for scientists and other expert users. The platform supports the geohazards community's objectives as defined in the context of the International Forum on Satellite EO and Geohazards organised by ESA and GEO in Santorini in 2012. The GEP is a follow on to the Supersites Exploitation Platform (SSEP) an ESA initiative to support the Geohazards Supersites & Natural Laboratories initiative (GSNL). Today the GEP allows to exploit 70+ Terabyte of ERS and ENVISAT archive and the Copernicus Sentinel-1 data available on line. The platform has already engaged 22 European early adopters in a validation activity initiated in March 2015. Since September, this validation has reached 29 single user projects. Each project is concerned with either integrating an application, running on demand processing or systematically generating a product collection using an application available in the platform. The users primarily include 15 geoscience centres and universities based in Europe: British Geological Survey (UK), University of Leeds (UK), University College London (UK), ETH University of Zurich (CH), INGV (IT), CNR-IREA and CNR-IRPI (IT), University of L'Aquila (IT), NOA (GR), Univ. Blaise Pascal & CNRS (FR), Ecole Normale Supérieure (FR), ISTERRE / University of Grenoble-Alpes (FR). In addition, there are users from Africa and North America with the University of Rabat (MA) and the University of Miami (US). Furthermore two space agencies and four private companies are involved: the German Space Research Centre DLR (DE), the European Space Agency (ESA), Altamira Information (ES

  3. Proteomic profiling of fibroblasts reveals a modulating effect of extracellular calumenin on the organization of the actin cytoskeleton

    DEFF Research Database (Denmark)

    Jensen, Morten Østergaard; Hansen, Gry Aune; Vorum, Henrik

    2006-01-01

    cytoskeleton and is involved in cytokinesis. Labeling of S phase fibroblasts with bromo-2'deoxy-uridine indicates that calumenin added to the medium also modulates the cell cycle. Our study thus indicates that calumenin possesses a paracrine role on the cells in its vicinity and therefore may be involved...... in the pathophysiology of thrombosis or in wound healing....

  4. c-Src Links a RANK/αvβ3 Integrin Complex to the Osteoclast Cytoskeleton

    Science.gov (United States)

    Izawa, Takashi; Zou, Wei; Chappel, Jean C.; Ashley, Jason W.; Feng, Xu

    2012-01-01

    RANK ligand (RANKL), by mechanisms unknown, directly activates osteoclasts to resorb bone. Because c-Src is key to organizing the cell's cytoskeleton, we asked if the tyrosine kinase also mediates RANKL-stimulated osteoclast activity. RANKL induces c-Src to associate with RANK369–373 in an αvβ3-dependent manner. Furthermore, RANK369–373 is the only one of six putative TRAF binding motifs sufficient to generate actin rings and activate the same cytoskeleton-organizing proteins as the integrin. While c-Src organizes the cell's cytoskeleton in response to the cytokine, it does not participate in RANKL-stimulated osteoclast formation. Attesting to their collaboration, αvβ3 and activated RANK coprecipitate, but only in the presence of c-Src. c-Src binds activated RANK via its Src homology 2 (SH2) domain and αvβ3 via its SH3 domain, suggesting the kinase links the two receptors. Supporting this hypothesis, deletion or inactivating point mutation of either the c-Src SH2 or SH3 domain obviates the RANK/αvβ3 association. Thus, activated RANK prompts two distinct signaling pathways; one promotes osteoclast formation, and the other, in collaboration with c-Src-mediated linkage to αvβ3, organizes the cell's cytoskeleton. PMID:22615494

  5. Neural cytoskeleton proteins in drug addiction%药物成瘾中的神经细胞骨架

    Institute of Scientific and Technical Information of China (English)

    蒋利和; 刘景根

    2011-01-01

    Neural cytoskeleton is important for neuronal function. Drug addiction leads to pathological nerve cells. In almost all drug addiction proteomic studies, the changes of cytoskeleton proteins were found. The studies have reported changes of cytoskeleton proteins that involve nerve cell structure, synaptic plasticity, signal transduction, protein degradation or modification and energy metabolism. The paper summaries the studies of neural cytoskeleton in drug addiction field.%神经细胞骨架对神经元功能有重要作用.药物成瘾会导致神经细胞病态发生,几乎在所有药物成瘾的蛋白质组学的研究中都能检测到细胞骨架蛋白的变化,细胞骨架蛋白在这个过程涉及神经细胞结构、突触可塑性、信号转导、功能蛋白的降解或修饰以及能量代谢等方面.本文综述了神经细胞骨架在药物成瘾中的研究.

  6. The translocation of signaling molecules in dark adapting mammalian rod photoreceptor cells is dependent on the cytoskeleton.

    Science.gov (United States)

    Reidel, Boris; Goldmann, Tobias; Giessl, Andreas; Wolfrum, Uwe

    2008-10-01

    In vertebrate rod photoreceptor cells, arrestin and the visual G-protein transducin move between the inner segment and outer segment in response to changes in light. This stimulus dependent translocation of signalling molecules is assumed to participate in long term light adaptation of photoreceptors. So far the cellular basis for the transport mechanisms underlying these intracellular movements remains largely elusive. Here we investigated the dependency of these movements on actin filaments and the microtubule cytoskeleton of photoreceptor cells. Co-cultures of mouse retina and retinal pigment epithelium were incubated with drugs stabilizing and destabilizing the cytoskeleton. The actin and microtubule cytoskeleton and the light dependent distribution of signaling molecules were subsequently analyzed by light and electron microscopy. The application of cytoskeletal drugs differentially affected the cytoskeleton in photoreceptor compartments. During dark adaptation the depolymerization of microtubules as well as actin filaments disrupted the translocation of arrestin and transducin in rod photoreceptor cells. During light adaptation only the delivery of arrestin within the outer segment was impaired after destabilization of microtubules. Movements of transducin and arrestin required intact cytoskeletal elements in dark adapting cells. However, diffusion might be sufficient for the fast molecular movements observed as cells adapt to light. These findings indicate that different molecular translocation mechanisms are responsible for the dark and light associated translocations of arrestin and transducin in rod photoreceptor cells.

  7. Identification of platform levels

    DEFF Research Database (Denmark)

    Mortensen, Niels Henrik

    2005-01-01

    reduction, ability to launch a wider product portfolio without increasing resources and reduction of complexity within the whole company. To support the multiple product development process, platform based product development has in many companies such as Philips, VW, Ford etc. proven to be a very effective...... and efficient tool. Transforming product development from single to multiple product development is a significant change in product development often involving major changes of product models, procedures and organization. In the area of product models a set of new models has to be introduced, e.g. models...

  8. RNA-binding proteins of the NXF (nuclear export factor) family and their connection with the cytoskeleton.

    Science.gov (United States)

    Mamon, L A; Ginanova, V R; Kliver, S F; Yakimova, A O; Atsapkina, A A; Golubkova, E V

    2017-04-01

    The mutual relationship between mRNA and the cytoskeleton can be seen from two points of view. On the one hand, the cytoskeleton is necessary for mRNA trafficking and anchoring to subcellular domains. On the other hand, cytoskeletal growth and rearrangement require the translation of mRNAs that are connected to the cytoskeleton. β-actin mRNA localization may influence dynamic changes in the actin cytoskeleton. In the cytoplasm, long-lived mRNAs exist in the form of RNP (ribonucleoprotein) complexes, where they interact with RNA-binding proteins, including NXF (Nuclear eXport Factor). Dm NXF1 is an evolutionarily conserved protein in Drosophila melanogaster that has orthologs in different animals. The universal function of nxf1 genes is the nuclear export of different mRNAs in various organisms. In this mini-review, we briefly discuss the evidence demonstrating that Dm NXF1 fulfils not only universal but also specialized cytoplasmic functions. This protein is detected not only in the nucleus but also in the cytoplasm. It is a component of neuronal granules. Dm NXF1 marks nuclear division spindles during early embryogenesis and the dense body on one side of the elongated spermatid nuclei. The characteristic features of sbr mutants (sbr(10) and sbr(5) ) are impairment of chromosome segregation and spindle formation anomalies during female meiosis. sbr(12) mutant sterile males with immobile spermatozoa exhibit disturbances in the axoneme, mitochondrial derivatives and cytokinesis. These data allow us to propose that the Dm NXF1 proteins transport certain mRNAs in neurites and interact with localized mRNAs that are necessary for dynamic changes of the cytoskeleton. © 2017 Wiley Periodicals, Inc.

  9. Cytoskeleton disorder and cell cycle arrest may be associated with the alteration of protein CEP135 by microgravity

    Science.gov (United States)

    Hang, Xiaoming; Sun, Yeqing; Wu, Di; Li, Yixiao; Liu, Zhiyuan

    In the past decades, alterations in the morphology, cytoskeleton and cell cycle have been observed in cells in vitro under microgravity conditions. But the underlying mechanisms are not absolutely identified yet. Our previous study on proteomic and microRNA expression profiles of zebrafish embryos exposed to simulated-microgravity has demonstrated a serial of microgravity-sensitive molecules. Centrosomal protein of 135 kDa (CEP135) was found down-regulated, but the mRNA expression level of it was up-regulated in zebrafish embryos after simulated-microgravity. However, the functional study on CEP135 is very limited and it has not been cloned in zebrafish till now. In this study, we try to determine whether the cytoskeleton disorder and cell cycle arrest is associated with the alteration of CEP135 by microgravity. Full-length cDNA of cep135 gene was firstly cloned from mitosis phase of ZF4. The sequence was analyzed and the phylogenetic tree was constructed based on the similarity to other species. Zebrafish embryonic cell line ZF4 were exposed to simulated microgravity for 24 and 48 hours, using a rotary cell culture system (RCCS) designed by NASA. Quantitative analysis by western blot showed that CEP135 expression level was significantly decreased two times after 24 hour simulated microgravity. Cell cycle detection by flow cytometer indicated ZF4 cells were blocked in G1 phase after 24 and 48 hour simulated microgravity. Moreover, double immunostained ZF4 cells with anti-tubulin and anti-CEP135antibodies demonstrated simulated microgravity could lead to cytoskeleton disorder and CEP135 abnormality. Further investigations are currently being carried out to determine whether knockdown and over-expression of CEP135 will modulate cytoskeleton and cell cycle. In vitro data in combination within vivo results might, at least in part, explain the dramatic effects of microgravity. Key Words: microgravity; CEP135; Cytoskeleton disorder; G1 arrest; ZF4 cell line

  10. Proteomic Analysis of the Action of the Mycobacterium ulcerans Toxin Mycolactone: Targeting Host Cells Cytoskeleton and Collagen

    Science.gov (United States)

    Gama, José B.; Ohlmeier, Steffen; Martins, Teresa G.; Fraga, Alexandra G.; Sampaio-Marques, Belém; Carvalho, Maria A.; Proença, Fernanda; Silva, Manuel T.; Pedrosa, Jorge; Ludovico, Paula

    2014-01-01

    Buruli ulcer (BU) is a neglected tropical disease caused by Mycobacterium ulcerans. The tissue damage characteristic of BU lesions is known to be driven by the secretion of the potent lipidic exotoxin mycolactone. However, the molecular action of mycolactone on host cell biology mediating cytopathogenesis is not fully understood. Here we applied two-dimensional electrophoresis (2-DE) to identify the mechanisms of mycolactone's cellular action in the L929 mouse fibroblast proteome. This revealed 20 changed spots corresponding to 18 proteins which were clustered mainly into cytoskeleton-related proteins (Dync1i2, Cfl1, Crmp2, Actg1, Stmn1) and collagen biosynthesis enzymes (Plod1, Plod3, P4ha1). In line with cytoskeleton conformational disarrangements that are observed by immunofluorescence, we found several regulators and constituents of both actin- and tubulin-cytoskeleton affected upon exposure to the toxin, providing a novel molecular basis for the effect of mycolactone. Consistent with these cytoskeleton-related alterations, accumulation of autophagosomes as well as an increased protein ubiquitination were observed in mycolactone-treated cells. In vivo analyses in a BU mouse model revealed mycolactone-dependent structural changes in collagen upon infection with M. ulcerans, associated with the reduction of dermal collagen content, which is in line with our proteomic finding of mycolactone-induced down-regulation of several collagen biosynthesis enzymes. Our results unveil the mechanisms of mycolactone-induced molecular cytopathogenesis on exposed host cells, with the toxin compromising cell structure and homeostasis by inducing cytoskeleton alterations, as well as disrupting tissue structure, by impairing the extracellular matrix biosynthesis. PMID:25101965

  11. Proteomic analysis of the action of the Mycobacterium ulcerans toxin mycolactone: targeting host cells cytoskeleton and collagen.

    Directory of Open Access Journals (Sweden)

    José B Gama

    2014-08-01

    Full Text Available Buruli ulcer (BU is a neglected tropical disease caused by Mycobacterium ulcerans. The tissue damage characteristic of BU lesions is known to be driven by the secretion of the potent lipidic exotoxin mycolactone. However, the molecular action of mycolactone on host cell biology mediating cytopathogenesis is not fully understood. Here we applied two-dimensional electrophoresis (2-DE to identify the mechanisms of mycolactone's cellular action in the L929 mouse fibroblast proteome. This revealed 20 changed spots corresponding to 18 proteins which were clustered mainly into cytoskeleton-related proteins (Dync1i2, Cfl1, Crmp2, Actg1, Stmn1 and collagen biosynthesis enzymes (Plod1, Plod3, P4ha1. In line with cytoskeleton conformational disarrangements that are observed by immunofluorescence, we found several regulators and constituents of both actin- and tubulin-cytoskeleton affected upon exposure to the toxin, providing a novel molecular basis for the effect of mycolactone. Consistent with these cytoskeleton-related alterations, accumulation of autophagosomes as well as an increased protein ubiquitination were observed in mycolactone-treated cells. In vivo analyses in a BU mouse model revealed mycolactone-dependent structural changes in collagen upon infection with M. ulcerans, associated with the reduction of dermal collagen content, which is in line with our proteomic finding of mycolactone-induced down-regulation of several collagen biosynthesis enzymes. Our results unveil the mechanisms of mycolactone-induced molecular cytopathogenesis on exposed host cells, with the toxin compromising cell structure and homeostasis by inducing cytoskeleton alterations, as well as disrupting tissue structure, by impairing the extracellular matrix biosynthesis.

  12. Cots Correlator Platform

    Science.gov (United States)

    Schaaf, Kjeld; Overeem, Ruud

    2004-06-01

    Moore’s law is best exploited by using consumer market hardware. In particular, the gaming industry pushes the limit of processor performance thus reducing the cost per raw flop even faster than Moore’s law predicts. Next to the cost benefits of Common-Of-The-Shelf (COTS) processing resources, there is a rapidly growing experience pool in cluster based processing. The typical Beowulf cluster of PC’s supercomputers are well known. Multiple examples exists of specialised cluster computers based on more advanced server nodes or even gaming stations. All these cluster machines build upon the same knowledge about cluster software management, scheduling, middleware libraries and mathematical libraries. In this study, we have integrated COTS processing resources and cluster nodes into a very high performance processing platform suitable for streaming data applications, in particular to implement a correlator. The required processing power for the correlator in modern radio telescopes is in the range of the larger supercomputers, which motivates the usage of supercomputer technology. Raw processing power is provided by graphical processors and is combined with an Infiniband host bus adapter with integrated data stream handling logic. With this processing platform a scalable correlator can be built with continuously growing processing power at consumer market prices.

  13. An Ultrasonographic Periodontal Probe

    Science.gov (United States)

    Bertoncini, C. A.; Hinders, M. K.

    2010-02-01

    Periodontal disease, commonly known as gum disease, affects millions of people. The current method of detecting periodontal pocket depth is painful, invasive, and inaccurate. As an alternative to manual probing, an ultrasonographic periodontal probe is being developed to use ultrasound echo waveforms to measure periodontal pocket depth, which is the main measure of periodontal disease. Wavelet transforms and pattern classification techniques are implemented in artificial intelligence routines that can automatically detect pocket depth. The main pattern classification technique used here, called a binary classification algorithm, compares test objects with only two possible pocket depth measurements at a time and relies on dimensionality reduction for the final determination. This method correctly identifies up to 90% of the ultrasonographic probe measurements within the manual probe's tolerance.

  14. Hard probes 2006 Asilomar

    CERN Multimedia

    2006-01-01

    "The second international conference on hard and electromagnetic probes of high-energy nuclear collisions was held June 9 to 16, 2006 at the Asilomar Conference grounds in Pacific Grove, California" (photo and 1/2 page)

  15. A low-profile three-dimensional neural probe array using a silicon lead transfer structure

    Science.gov (United States)

    Cheng, Ming-Yuan; Je, Minkyu; Tan, Kwan Ling; Lim Tan, Ee; Lim, Ruiqi; Yao, Lei; Li, Peng; Park, Woo-Tae; Phua, Eric Jian Rong; Lip Gan, Chee; Yu, Aibin

    2013-09-01

    This paper presents a microassembly method for low-profile three-dimensional probe arrays for neural prosthesis and neuroscience applications. A silicon (Si) lead transfer structure, Si interposer, is employed to form electrical connections between two orthogonal planes—the two dimensional probes and the dummy application-specific integrated circuit (ASIC) chip. In order to hold the probe array and facilitate the alignment of probes during assembly, a Si platform is designed to have through-substrate slots for the insertion of probes and cavities for holding the Si interposers. The electrical interconnections between the probes and the dummy ASIC chip are formed by solder reflow, resulting in greatly improved throughput in the proposed assembly method. Moreover, since the backbone of the probe can be embedded inside the cavity of the Si platform, the profile of the probe array above the cortical surface can be controlled within 750 µm. This low-profile allows the probe array not to touch the skull after it is implanted on the brain. The impedance of the assembled probe is also measured and discussed.

  16. Communications payloads for geostationary platforms

    Science.gov (United States)

    Fordyce, S. W.

    1978-01-01

    Trends in communication satellites show increasing reuse of the frequency spectrum through multiple spot beams and orthogonal polarization, as well as consortia operation. Current reliance on orbital arc separation for frequency reuse may be inadequate for the projected traffic growth and the orbital slotting proposals before the ITU. This paper notes that cost advantages can accrue through common use of spacecraft subsystems and multiple users' platforms aboard a common geostationary platform. The rationale for such platforms is described and potential payloads are suggested.

  17. Utilizing platforms in industrialized construction

    DEFF Research Database (Denmark)

    Bonev, Martin; Wörösch, Michael; Hvam, Lars

    2015-01-01

    construction companies. A promising approach adapted by operations management and design theory regards individual building projects as the adjustment and recombination of components and processes from a set of predefined platforms, while configuration systems assure feasible building solutions. Design...... methods map structural platform characteristics so as to balance commonality and distinctiveness. Originality/value – This paper proposes a general theory of platform-based development and execution in the industrialised construction sector, which goes beyond concurrent approaches of standardising...

  18. Dynamic probe selection for studying microbial transcriptome with high-density genomic tiling microarrays

    Directory of Open Access Journals (Sweden)

    Chen Tsute

    2010-02-01

    Full Text Available Abstract Background Current commercial high-density oligonucleotide microarrays can hold millions of probe spots on a single microscopic glass slide and are ideal for studying the transcriptome of microbial genomes using a tiling probe design. This paper describes a comprehensive computational pipeline implemented specifically for designing tiling probe sets to study microbial transcriptome profiles. Results The pipeline identifies every possible probe sequence from both forward and reverse-complement strands of all DNA sequences in the target genome including circular or linear chromosomes and plasmids. Final probe sequence lengths are adjusted based on the maximal oligonucleotide synthesis cycles and best isothermality allowed. Optimal probes are then selected in two stages - sequential and gap-filling. In the sequential stage, probes are selected from sequence windows tiled alongside the genome. In the gap-filling stage, additional probes are selected from the largest gaps between adjacent probes that have already been selected, until a predefined number of probes is reached. Selection of the highest quality probe within each window and gap is based on five criteria: sequence uniqueness, probe self-annealing, melting temperature, oligonucleotide length, and probe position. Conclusions The probe selection pipeline evaluates global and local probe sequence properties and selects a set of probes dynamically and evenly distributed along the target genome. Unique to other similar methods, an exact number of non-redundant probes can be designed to utilize all the available probe spots on any chosen microarray platform. The pipeline can be applied to microbial genomes when designing high-density tiling arrays for comparative genomics, ChIP chip, gene expression and comprehensive transcriptome studies.

  19. Web Platform Application

    Energy Technology Data Exchange (ETDEWEB)

    Paulsworth, Ashley [Sunvestment Group, Frederick, MD (United States); Kurtz, Jim [Sunvestment Group, Frederick, MD (United States); Brun de Pontet, Stephanie [Sunvestment Group, Frederick, MD (United States)

    2016-06-15

    Sunvestment Energy Group (previously called Sunvestment Group) was established to create a web application that brings together site hosts, those who will obtain the energy from the solar array, with project developers and funders, including affinity investors. Sunvestment Energy Group (SEG) uses a community-based model that engages with investors who have some affinity with the site host organization. In addition to a financial return, these investors receive non-financial value from their investments and are therefore willing to offer lower cost capital. This enables the site host to enjoy more savings from solar through these less expensive Community Power Purchase Agreements (CPPAs). The purpose of this award was to develop an online platform to bring site hosts and investors together virtually.

  20. Energy Tracking Software Platform

    Energy Technology Data Exchange (ETDEWEB)

    Ryan Davis; Nathan Bird; Rebecca Birx; Hal Knowles

    2011-04-04

    Acceleration has created an interactive energy tracking and visualization platform that supports decreasing electric, water, and gas usage. Homeowners have access to tools that allow them to gauge their use and track progress toward a smaller energy footprint. Real estate agents have access to consumption data, allowing for sharing a comparison with potential home buyers. Home builders have the opportunity to compare their neighborhood's energy efficiency with competitors. Home energy raters have a tool for gauging the progress of their clients after efficiency changes. And, social groups are able to help encourage members to reduce their energy bills and help their environment. EnergyIT.com is the business umbrella for all energy tracking solutions and is designed to provide information about our energy tracking software and promote sales. CompareAndConserve.com (Gainesville-Green.com) helps homeowners conserve energy through education and competition. ToolsForTenants.com helps renters factor energy usage into their housing decisions.

  1. The Creative Soccer Platform

    DEFF Research Database (Denmark)

    Johan Torp Rasmussen, Ludvig; Østergaard, Lars Domino

    2016-01-01

    Creativity is essential in soccer due to the unpredictable and complex situations occurring in the game, where stereotypical play gradually loses its efficiency. Further, creativity is an important psychological factor for the development of soccer expertise, and valuing creativity increases...... satisfaction and well-being. Although creative players are highly desired by coaches, the subject of cultivating creativity is mostly ignored and traditional training settings may even hamper the players' creativity. The purpose of this article is to introduce a novel approach for enhancing soccer players......' creativity, The Creative Soccer Platform (TCSP), and to demonstrate the implications of applying it in youth soccer practice, by means of soccer-specific creativity exercises. TCSP encompasses four theoretically based didactic principles (task focus, parallel thinking, horizontal thinking, and no experienced...

  2. Fractal dimension as a measure of altered actin cytoskeleton in MC3T3-E1 cells under simulated microgravity using 3-D/2-D clinostats.

    Science.gov (United States)

    Qian, A R; Li, D; Han, J; Gao, X; Di, S M; Zhang, W; Hu, L F; Shang, Peng

    2012-05-01

    Osteoblasts, the bone-forming cells, respond to various mechanical forces, such as stretch and fluid shear force in essentially similar ways. The cytoskeleton, as the load-bearing architecture of the cell, is sensitive to altered inertial forces. Disruption of the cytoskeleton will result in alteration of cellular structure and function. However, it is difficult to quantitatively illustrate cytoskeletal rearrangement because of the complexity of cytoskeletal structure. Usually, the morphological changes in actin organization caused by external stimulus are basically descriptive. In this study, fractal dimensions (D) analysis was used to quantify the morphological changes in the actin cytoskeleton of osteoblast-like cells (MC3T3-E1) under simulated microgravity using 3-D/2-D clinostats. The ImageJ software was used to count the fractal dimension of actin cytoskeleton by box-counting methods. Real-time PCR and immunofluroscent assays were used to further confirm the results obtained by fractal dimension analysis. The results showed significant decreases in D value of actin cytoskeleton, β-actin mRNA expression, and the mean fluorescence intensity of F-actin in osteoblast-like cells after 24 or 48 h of incubation under 3-D/2-D clinorotation condition compared with control. The findings indicate that 3-D/2-D clinorotation affects both actin cytoskeleton architecture and mRNA expression, and fractal may be a promising approach for quantitative analysis of the changes in cytoskeleton in different environments.

  3. Power Quality Indices Estimation Platform

    Directory of Open Access Journals (Sweden)

    Eliana I. Arango-Zuluaga

    2013-11-01

    Full Text Available An interactive platform for estimating the quality indices in single phase electric power systems is presented. It meets the IEEE 1459-2010 standard recommendations. The platform was developed in order to support teaching and research activities in electric power quality. The platform estimates the power quality indices from voltage and current signals using three different algorithms based on fast Fourier transform (FFT, wavelet packet transform (WPT and least squares method. The results show that the algorithms implemented are efficient for estimating the quality indices of the power and the platform can be used according to the objectives established. 

  4. Flexible experimental FPGA based platform

    DEFF Research Database (Denmark)

    Andersen, Karsten Holm; Nymand, Morten

    2016-01-01

    This paper presents an experimental flexible Field Programmable Gate Array (FPGA) based platform for testing and verifying digital controlled dc-dc converters. The platform supports different types of control strategies, dc-dc converter topologies and switching frequencies. The controller platform...... interface supporting configuration and reading of setup parameters, controller status and the acquisition memory in a simple way. The FPGA based platform, provides an easy way within education or research to use different digital control strategies and different converter topologies controlled by an FPGA...

  5. Product Platform Screening at LEGO

    DEFF Research Database (Denmark)

    Mortensen, Niels Henrik; Steen Jensen, Thomas; Nielsen, Ole Fiil

    2012-01-01

    Product platforms offer great benefits to companies developing new products in highly competitive markets. Literature describes how a single platform can be designed from a technical point of view, but rarely mentions how the process begins. How do companies identify possible platform candidates...... after a few changes had been applied to the initial process layout. This case study shows how companies must focus on a limited selection of simultaneous projects in order to keep focus. Primary stakeholders must be involved from the very beginning, and short presentations of the platform concepts...

  6. Platform evolution studies

    Science.gov (United States)

    Walton, Barbara A.

    1990-01-01

    The polar orbiting platform (POP), being developed by the Work Package 3 (WP3) Project at the Goddard Space Flight Center, will play a key role in the NASA Leadership Initiative, Mission to Planet Earth (MPE). It becomes, with the addition of payloads, an Earth observation satellite observatory. Mission to Planet Earth also has geostationary platforms (GEOP) as part of its global observational system. A study was begun in March 1988 to assess the applicability of the POP orbital replacement units (ORUs) for a geostationary Earth observing mission. Two test cases, representative of MPE payloads, were studied. Case A was used to emphasize the GEOP configuration and design; it used a Titan/Centaur to achieve orbit. Case B, considered to be much further in the future, included some assembly at the Space Station Freedom manned base and use of an orbital transfer vehicle to achieve orbit; requirements on the manned base to support such a mission were emphasized. The study found the POP systems more than adequate to meet GEOP requirements. Two types of changes were required for the POP ORUs: (1) modification to use only one surface for heat rejection; for the battery ORU, this meant 'opening up' the ORU to retain the radiator area with a corresponding decrease in depth; and (2) deletion of equipment not needed. The Case A configuration was shown to be within the planned capability of the Titan IV/Centaur. Assembly requirements were included for the Case B configuration, which is driven by the large microwave antennas of two of the payloads. The final review was April 19, 1989.

  7. Probing cell mechanical properties with microfluidic devices

    Science.gov (United States)

    Rowat, Amy

    2012-02-01

    Exploiting flow on the micron-scale is emerging as a method to probe cell mechanical properties with 10-1000x advances in throughput over existing technologies. The mechanical properties of cells and the cell nucleus are implicated in a wide range of biological contexts: for example, the ability of white blood cells to deform is central to immune response; and malignant cells show decreased stiffness compared to benign cells. We recently developed a microfluidic device to probe cell and nucleus mechanical properties: cells are forced to deform through a narrow constrictions in response to an applied pressure; flowing cells through a series of constrictions enables us to probe the ability of hundreds of cells to deform and relax during flow. By tuning the constriction width so it is narrower than the width of the cell nucleus, we can specifically probe the effects of nuclear physical properties on whole cell deformability. We show that the nucleus is the rate-limiting step in cell passage: inducing a change in its shape to a multilobed structure results in cells that transit more quickly; increased levels of lamin A, a nuclear protein that is key for nuclear shape and mechanical stability, impairs the passage of cells through constrictions. We are currently developing a new class of microfluidic devices to simultaneously probe the deformability of hundreds of cell samples in parallel. Using the same soft lithography techniques, membranes are fabricated to have well-defined pore distribution, width, length, and tortuosity. We design the membranes to interface with a multiwell plate, enabling simultaneous measurement of hundreds of different samples. Given the wide spectrum of diseases where altered cell and nucleus mechanical properties are implicated, such a platform has great potential, for example, to screen cells based on their mechanical phenotype against a library of drugs.

  8. Microbial metabolomics in open microscale platforms

    Science.gov (United States)

    Barkal, Layla J.; Theberge, Ashleigh B.; Guo, Chun-Jun; Spraker, Joe; Rappert, Lucas; Berthier, Jean; Brakke, Kenneth A.; Wang, Clay C. C.; Beebe, David J.; Keller, Nancy P.; Berthier, Erwin

    2016-01-01

    The microbial secondary metabolome encompasses great synthetic diversity, empowering microbes to tune their chemical responses to changing microenvironments. Traditional metabolomics methods are ill-equipped to probe a wide variety of environments or environmental dynamics. Here we introduce a class of microscale culture platforms to analyse chemical diversity of fungal and bacterial secondary metabolomes. By leveraging stable biphasic interfaces to integrate microculture with small molecule isolation via liquid–liquid extraction, we enable metabolomics-scale analysis using mass spectrometry. This platform facilitates exploration of culture microenvironments (including rare media typically inaccessible using established methods), unusual organic solvents for metabolite isolation and microbial mutants. Utilizing Aspergillus, a fungal genus known for its rich secondary metabolism, we characterize the effects of culture geometry and growth matrix on secondary metabolism, highlighting the potential use of microscale systems to unlock unknown or cryptic secondary metabolites for natural products discovery. Finally, we demonstrate the potential for this class of microfluidic systems to study interkingdom communication between fungi and bacteria. PMID:26842393

  9. Platform Performance and Challenges - using Platforms in Lego Company

    DEFF Research Database (Denmark)

    Munk, Lone; Mortensen, Niels Henrik

    2009-01-01

    This article studies the performance and challenges of using nine implemented product platforms in LEGO Company. Most of these do produce results, but do not meet their goals due to challenges in their usage in the daily product. The main challenges are that the platforms are not being used...

  10. Integrin-linked kinase regulates oligodendrocyte cytoskeleton, growth cone, and adhesion dynamics.

    Science.gov (United States)

    Michalski, John-Paul; Cummings, Sarah E; O'Meara, Ryan W; Kothary, Rashmi

    2016-02-01

    Integrin-linked kinase (ILK), a focal adhesion protein, brokers the link between cytoskeleton, cell membrane, and extracellular environment. Here, we demonstrate a role for ILK in laminin-2-mediated adhesion in primary murine oligodendrocytes (OLs) - with ILK loss leading to severe defects in process branching and outgrowth. These defects were partially recovered when the ILK-depleted OLs were instead grown on the non-integrin-activating substrate poly-l-lysine. Intriguingly, ILK loss on the neutral poly-l-lysine substrate led to swelling at the tips of OL processes, which we identified as enlarged growth cones. Employing the bloated ILK-depleted growth cones as template, we demonstrate the appearance of distinct cytoskeletal domains within OL growth cones bearing classic neuronal growth cone architecture. Further, microtubule organization was severely perturbed following ILK loss, with centripetal microtubule looping and failure to bundle occurring in a laminin-2-independent manner. Together, our work highlights differences in specific aspects of OL biology as driven by laminin-2-dependent or independent ILK governed mechanisms. We also reinforce the idea of OLs as growth cone bearing cells and describe the neuronal-like cytoskeleton therein. Finally, we demonstrate a role for ILK in OL growth cone maturation through microtubule regulation, the loss of which translates to decreased process length and myelin production capacity. We describe herein how different substrates fundamentally alter the oligodendrocyte's response to loss of integrin-linked kinase (ILK). On laminin-2 (Ln-2), ILK-depleted oligodendrocytes appear stunted and malformed, while on the non-integrin-activating substrate PLL branching and membrane formation are restored. We also reinforce the idea of oligodendrocytes as growth cone-bearing cells, detailing the growth cone's cytoskeletal architecture. Strikingly, loss of ILK on poly-l-lysine leads to growth cone swelling, the structure's size and

  11. Actin cytoskeleton regulation of epithelial mesenchymal transition in metastatic cancer cells.

    Directory of Open Access Journals (Sweden)

    Jay Shankar

    Full Text Available Epithelial-mesenchymal transition (EMT is associated with loss of the cell-cell adhesion molecule E-cadherin and disruption of cell-cell junctions as well as with acquisition of migratory properties including reorganization of the actin cytoskeleton and activation of the RhoA GTPase. Here we show that depolymerization of the actin cytoskeleton of various metastatic cancer cell lines with Cytochalasin D (Cyt D reduces cell size and F-actin levels and induces E-cadherin expression at both the protein and mRNA level. Induction of E-cadherin was dose dependent and paralleled loss of the mesenchymal markers N-cadherin and vimentin. E-cadherin levels increased 2 hours after addition of Cyt D in cells showing an E-cadherin mRNA response but only after 10-12 hours in HT-1080 fibrosarcoma and MDA-MB-231 cells in which E-cadherin mRNA level were only minimally affected by Cyt D. Cyt D treatment induced the nuclear-cytoplasmic translocation of EMT-associated SNAI 1 and SMAD1/2/3 transcription factors. In non-metastatic MCF-7 breast cancer cells, that express E-cadherin and represent a cancer cell model for EMT, actin depolymerization with Cyt D induced elevated E-cadherin while actin stabilization with Jasplakinolide reduced E-cadherin levels. Elevated E-cadherin levels due to Cyt D were associated with reduced activation of Rho A. Expression of dominant-negative Rho A mutant increased and dominant-active Rho A mutant decreased E-cadherin levels and also prevented Cyt D induction of E-cadherin. Reduced Rho A activation downstream of actin remodelling therefore induces E-cadherin and reverses EMT in cancer cells. Cyt D treatment inhibited migration and, at higher concentrations, induced cytotoxicity of both HT-1080 fibrosarcoma cells and normal Hs27 fibroblasts, but only induced mesenchymal-epithelial transition in HT-1080 cancer cells. Our studies suggest that actin remodelling is an upstream regulator of EMT in metastatic cancer cells.

  12. A heat-sinking self-referencing fiber optic emission probe

    Science.gov (United States)

    Djeu, Nicholas; Shimoji, Yutaka

    2016-09-01

    A novel heat-sinking, self-referencing fiber optic emission probe having a sapphire fiber probe head is described. The laser heating effect in a GaAs wafer (on a polytetrafluoroethylene (PTFE) platform) has been measured with the probe in both the noncontact proximity mode and the contact mode. The GaAs/PTFE composite was selected to simulate the thermal conductivity of animal tissues. It was found that for the same laser power delivered to the wafer, the temperature rise in the contact mode was only 42% of that in the proximity mode. Additionally, a demonstration of the self-referencing capability of the probe is also presented.

  13. Filamentous brown algae infected by the marine, holocarpic oomycete Eurychasma dicksonii: first results on the organization and the role of cytoskeleton in both host and parasite.

    Science.gov (United States)

    Tsirigoti, Amerssa; Kuepper, Frithjof C; Gachon, Claire Mm; Katsaros, Christos

    2013-11-01

    The important role of the cytoskeletal scaffold is increasingly recognized in host-pathogen interactions. The cytoskeleton potentially functions as a weapon for both the plants defending themselves against fungal or oomycete parasites, and for the pathogens trying to overcome the resisting barrier of the plants. This concept, however, had not been investigated in marine algae so far. We are opening this scientific chapter with our study on the functional implications of the cytoskeleton in 3 filamentous brown algal species infected by the marine oomycete Eurychasma dicksonii. Our observations suggest that the cytoskeleton is involved in host defense responses and in fundamental developmental stages of E. dicksonii in its algal host.

  14. Space and time-resolved probing of heterogeneous catalysis reactions using lab-on-a-chip

    Science.gov (United States)

    Navin, Chelliah V.; Krishna, Katla Sai; Theegala, Chandra S.; Kumar, Challa S. S. R.

    2016-03-01

    Probing catalytic reactions on a catalyst surface in real time is a major challenge. Herein, we demonstrate the utility of a continuous flow millifluidic chip reactor coated with a nanostructured gold catalyst as an effective platform for in situ investigation of the kinetics of catalytic reactions by taking 5-(hydroxymethyl)furfural (HMF) to 2,5-furandicarboxylic acid (FDCA) conversion as a model reaction. The idea conceptualized in this paper can not only dramatically change the ability to probe the time-resolved kinetics of heterogeneous catalysis reactions but also used for investigating other chemical and biological catalytic processes, thereby making this a broad platform for probing reactions as they occur within continuous flow reactors.Probing catalytic reactions on a catalyst surface in real time is a major challenge. Herein, we demonstrate the utility of a continuous flow millifluidic chip reactor coated with a nanostructured gold catalyst as an effective platform for in situ investigation of the kinetics of catalytic reactions by taking 5-(hydroxymethyl)furfural (HMF) to 2,5-furandicarboxylic acid (FDCA) conversion as a model reaction. The idea conceptualized in this paper can not only dramatically change the ability to probe the time-resolved kinetics of heterogeneous catalysis reactions but also used for investigating other chemical and biological catalytic processes, thereby making this a broad platform for probing reactions as they occur within continuous flow reactors. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06752a

  15. Rapid prototyping of robotic platforms

    CSIR Research Space (South Africa)

    De Ronde, Willis

    2016-11-01

    Full Text Available Building a robotic platform from raw materials can take anything from a few weeks to a few years to complete, depending on the complexity and size of the platform. This paper aims to introduce a novel approach of using abrasive waterjet machining...

  16. Preparing for a Product Platform

    DEFF Research Database (Denmark)

    Fiil-Nielsen, Ole; Munk, Lone; Mortensen, Niels Henrik

    2005-01-01

    they lead to increased sales due to more customized product as well as decreased costs due to reuse, making a product development platform a very profitable strategy for product developing companies. A successful implementation of a product development platform is not straightforward though...

  17. Effects of indomethacin on the divisional morphogenesis and cytoskeleton-dependent processes of Tetrahymena.

    Science.gov (United States)

    Kovács, Péter; Pállinger, Eva

    2003-06-01

    Indomethacin (0.1 mM) causes significantly altered phospholipid synthesis in Tetrahymena and is able to influence the inositol phospholipid signalling system (9). In the present study the effects of indomethacin on the course of cell division, cyclin expression, the cortical microtubular system and on cytoskeleton-dependent processes (motility, phagocytosis) were investigated. As expected from its interference with the synthesis of phospholipids, indomethacin affected Tetrahymena in a number of ways: the structure of the cortical microtubular system became irregular; in many cells the stomatogenesis (development of new oral apparatus) and the development of the fission furrow was not accompanied by elongation of the macronucleus, which is a typical phenomenon of the normal course of mitosis: apparently indomethacin uncouples these phenomena. After indomethacin treatment, the expression of both cyclin A and cyclin B(1) were reduced significantly. The cell growth rate, motility and phagocytotic activity were all considerably reduced. There are probably additional mechanisms responsible for the effect of indomethacin on the systems that control divisional morphogenesis, for microtubule-dependent processes and for the connection between nuclear and cortical alterations during the cell cycle. Effects on protein phosphorylation/dephosphorylation, on cyclin expression and on microtubular functions are probably involved. These possibilities are discussed.

  18. Interactions between Leishmania braziliensis and Macrophages Are Dependent on the Cytoskeleton and Myosin Va

    Directory of Open Access Journals (Sweden)

    Elisama Azevedo

    2012-01-01

    Full Text Available Leishmaniasis is a neglected tropical disease with no effective vaccines. Actin, microtubules and the actin-based molecular motor myosin Va were investigated for their involvement in Leishmania braziliensis macrophage interactions. Results showed a decrease in the association index when macrophages were without F-actin or microtubules regardless of the activation state of the macrophage. In the absence of F-actin, the production of NO in non-activated cells increased, while in activated cells, the production of NO was reduced independent of parasites. The opposite effect of an increased NO production was observed in the absence of microtubules. In activated cells, the loss of cytoskeletal components inhibited the release of IL-10 during parasite interactions. The production of IL-10 also decreased in the absence of actin or microtubules in non-activated macrophages. Only the disruption of actin altered the production of TNF-α in activated macrophages. The expression of myosin Va tail resulted in an acute decrease in the association index between transfected macrophages and L. braziliensis promastigotes. These data reveal the importance of F-actin, microtubules, and myosin-Va suggesting that modulation of the cytoskeleton may be a mechanism used by L. braziliensis to overcome the natural responses of macrophages to establish infections.

  19. Intracellular transport of viruses and their components: utilizing the cytoskeleton and membrane highways.

    Science.gov (United States)

    Harries, Phillip A; Schoelz, James E; Nelson, Richard S

    2010-11-01

    Plant viruses are obligate organisms that require host components for movement within and between cells. A mechanistic understanding of virus movement will allow the identification of new methods to control virus systemic spread and serve as a model system for understanding host macromolecule intra- and intercellular transport. Recent studies have moved beyond the identification of virus proteins involved in virus movement and their effect on plasmodesmal size exclusion limits to the analysis of their interactions with host components to allow movement within and between cells. It is clear that individual virus proteins and replication complexes associate with and, in some cases, traffic along the host cytoskeleton and membranes. Here, we review these recent findings, highlighting the diverse associations observed between these components and their trafficking capacity. Plant viruses operate individually, sometimes within virus species, to utilize unique interactions between their proteins or complexes and individual host cytoskeletal or membrane elements over time or space for their movement. However, there is not sufficient information for any plant virus to create a complete model of its intracellular movement; thus, more research is needed to achieve that goal.

  20. Resistance to dopamine agonists and somatostatin analogues in pituitary tumors: focus on cytoskeleton involvement

    Directory of Open Access Journals (Sweden)

    Erika ePeverelli

    2015-12-01

    Full Text Available Pituitary tumors, that origin from excessive proliferation of a specific subtype of pituitary cell, are mostly benign tumors, but may cause significant morbidity in affected patients, including visual and neurologic manifestations from mass-effect, or endocrine syndromes caused by hormone hypersecretion. Dopamine (DA receptor DRD2 and somatostatin (SS receptors (SSTRs represent the main targets of pharmacological treatment of pituitary tumors since they mediate inhibitory effects on both hormone secretion and cell proliferation, and their expression is retained by most of these tumors. Although long acting DA and SS analogs are currently used in the treatment of prolactin (PRL- and growth hormone (GH-secreting pituitary tumors, respectively, clinical practice indicates a great variability in the frequency and entity of favourable responses. The molecular basis of the pharmacological resistance are still poorly understood, and several potential molecular mechanisms have been proposed, including defective expression or genetic alterations of DRD2 and SSTRs, or an impaired signal transduction. Recently, a role for cytoskeleton protein filamin A (FLNA in DRD2 and SSTRs receptors expression and signalling in PRL- and GH- secreting tumors, respectively, has been demonstrated, first revealing a link between FLNA expression and responsiveness of pituitary tumors to pharmacological therapy. This review provides an overview of the known molecular events involved in SS and DA resistance, focusing on the role played by FLNA.

  1. Novel regulation of Ski protein stability and endosomal sorting by actin cytoskeleton dynamics in hepatocytes.

    Science.gov (United States)

    Vázquez-Victorio, Genaro; Caligaris, Cassandre; Del Valle-Espinosa, Eugenio; Sosa-Garrocho, Marcela; González-Arenas, Nelly R; Reyes-Cruz, Guadalupe; Briones-Orta, Marco A; Macías-Silva, Marina

    2015-02-13

    TGF-β-induced antimitotic signals are highly regulated during cell proliferation under normal and pathological conditions, such as liver regeneration and cancer. Up-regulation of the transcriptional cofactors Ski and SnoN during liver regeneration may favor hepatocyte proliferation by inhibiting TGF-β signals. In this study, we found a novel mechanism that regulates Ski protein stability through TGF-β and G protein-coupled receptor (GPCR) signaling. Ski protein is distributed between the nucleus and cytoplasm of normal hepatocytes, and the molecular mechanisms controlling Ski protein stability involve the participation of actin cytoskeleton dynamics. Cytoplasmic Ski is partially associated with actin and localized in cholesterol-rich vesicles. Ski protein stability is decreased by TGF-β/Smads, GPCR/Rho signals, and actin polymerization, whereas GPCR/cAMP signals and actin depolymerization promote Ski protein stability. In conclusion, TGF-β and GPCR signals differentially regulate Ski protein stability and sorting in hepatocytes, and this cross-talk may occur during liver regeneration.

  2. E-cadherin couples death receptors to the cytoskeleton to regulate apoptosis.

    Science.gov (United States)

    Lu, Min; Marsters, Scot; Ye, Xiaofen; Luis, Elizabeth; Gonzalez, Lino; Ashkenazi, Avi

    2014-06-19

    Epithelial-to-mesenchymal transition (EMT) is a cellular process essential to the development and maintenance of solid tissues. In cancer, EMT suppresses apoptosis, but the mechanisms remain unclear. EMT selectively attenuated apoptosis signaling via the death receptors DR4 and DR5. Loss of the epithelial cell adhesion protein E-cadherin recapitulated this outcome, whereas homotypic E-cadherin engagement promoted apoptotic signaling via DR4/DR5, but not Fas. Depletion of α-catenin, which couples E-cadherin to the actin cytoskeleton, or actin polymerization inhibitors similarly attenuated DR4/DR5-induced apoptosis. E-cadherin bound specifically to ligated DR4/DR5, requiring extracellular cadherin domain 1 and calcium. E-cadherin augmented DR4/DR5 clustering and assembly of the death-inducing signaling complex (DISC), increasing caspase-8 activation in high molecular weight cell fractions. Conversely, EMT attenuated DR4/DR5-mediated DISC formation and caspase-8 stimulation. Consistent with these findings, epithelial cancer cell lines expressing higher E-cadherin levels displayed greater sensitivity to DR4/DR5-mediated apoptosis. These results have potential implications for tissue homeostasis as well as cancer therapy.

  3. Biogenesis of the trypanosome endo-exocytotic organelle is cytoskeleton mediated.

    Directory of Open Access Journals (Sweden)

    Mélanie Bonhivers

    2008-05-01

    Full Text Available Trypanosoma brucei is a protozoan parasite that is used as a model organism to study such biological phenomena as gene expression, protein trafficking, and cytoskeletal biogenesis. In T. brucei, endocytosis and exocytosis occur exclusively through a sequestered organelle called the flagellar pocket (FP, an invagination of the pellicular membrane. The pocket is the sole site for specific receptors thus maintaining them inaccessible to components of the innate immune system of the mammalian host. The FP is also responsible for the sorting of protective parasite glycoproteins targeted to, or recycling from, the pellicular membrane, and for the removal of host antibodies from the cell surface. Here, we describe the first characterisation of a flagellar pocket cytoskeletal protein, BILBO1. BILBO1 functions to form a cytoskeleton framework upon which the FP is made and which is also required and essential for FP biogenesis and cell survival. Remarkably, RNA interference (RNAi-mediated ablation of BILBO1 in insect procyclic-form parasites prevents FP biogenesis and induces vesicle accumulation, Golgi swelling, the aberrant repositioning of the new flagellum, and cell death. Cultured bloodstream-form parasites are also nonviable when subjected to BILBO1 RNAi. These results provide the first molecular evidence for cytoskeletally mediated FP biogenesis.

  4. N-cadherin negatively regulates collective Drosophila glial migration through actin cytoskeleton remodeling.

    Science.gov (United States)

    Kumar, Arun; Gupta, Tripti; Berzsenyi, Sara; Giangrande, Angela

    2015-03-01

    Cell migration is an essential and highly regulated process. During development, glia cells and neurons migrate over long distances - in most cases collectively - to reach their final destination and build the sophisticated architecture of the nervous system, the most complex tissue of the body. Collective migration is highly stereotyped and efficient, defects in the process leading to severe human diseases that include mental retardation. This dynamic process entails extensive cell communication and coordination, hence, the real challenge is to analyze it in the entire organism and at cellular resolution. We here investigate the impact of the N-cadherin adhesion molecule on collective glial migration, by using the Drosophila developing wing and cell-type specific manipulation of gene expression. We show that N-cadherin timely accumulates in glial cells and that its levels affect migration efficiency. N-cadherin works as a molecular brake in a dosage-dependent manner, by negatively controlling actin nucleation and cytoskeleton remodeling through α/β catenins. This is the first in vivo evidence for N-cadherin negatively and cell autonomously controlling collective migration.

  5. Fascin links Btl/FGFR signalling to the actin cytoskeleton during Drosophila tracheal morphogenesis.

    Science.gov (United States)

    Okenve-Ramos, Pilar; Llimargas, Marta

    2014-02-01

    A key challenge in normal development and in disease is to elucidate the mechanisms of cell migration. Here we approach this question using the tracheal system of Drosophila as a model. Tracheal cell migration requires the Breathless/FGFR pathway; however, how the pathway induces migration remains poorly understood. We find that the Breathless pathway upregulates singed at the tip of tracheal branches, and that this regulation is functionally relevant. singed encodes Drosophila Fascin, which belongs to a conserved family of actin-bundling proteins involved in cancer progression and metastasis upon misregulation. We show that singed is required for filopodia stiffness and proper morphology of tracheal tip cells, defects that correlate with an abnormal actin organisation. We propose that singed-regulated filopodia and cell fronts are required for timely and guided branch migration and for terminal branching and branch fusion. We find that singed requirements rely on its actin-bundling activity controlled by phosphorylation, and that active Singed can promote tip cell features. Furthermore, we find that singed acts in concert with forked, another actin cross-linker. The absence of both cross-linkers further stresses the relevance of tip cell morphology and filopodia for tracheal development. In summary, our results on the one hand reveal a previously undescribed role for forked in the organisation of transient actin structures such as filopodia, and on the other hand identify singed as a new target of Breathless signal, establishing a link between guidance cues, the actin cytoskeleton and tracheal morphogenesis.

  6. Capping protein beta is required for actin cytoskeleton organisation and cell migration during Drosophila oogenesis.

    Science.gov (United States)

    Ogienko, Anna A; Karagodin, Dmitry A; Lashina, Valentina V; Baiborodin, Sergey I; Omelina, Eugeniya S; Baricheva, Elina M

    2013-02-01

    Capping protein (CP) is a well-characterised actin-binding protein important for regulation of actin filament (AF) assembly. CP caps the barbed end of AFs, inhibiting the addition and loss of actin monomers. In Drosophila melanogaster, the gene encoding CP β-subunit is named capping protein beta (cpb; see Hopmann et al. [1996] J Cell Biol 133: 1293-305). The cpb level is reduced in the Drosophila bristle actin cytoskeleton and becomes disorganised with abnormal morphology. A reduced level of the CP protein in ovary results in disruption of oocyte determination, and disturbance of nurse cell (NC) cortical integrity and dumping. We describe novel defects appearing in cpb mutants during oogenesis, in which cpb plays an important role in border and centripetal follicle cell migration, ring canal development and cytoplasmic AF formation. The number of long cytoplasmic AFs was dramatically reduced in cpb hypomorphs and abnormal actin aggregates was seen on the inner side of NC membranes. A hypothesis to explain the formation of abnormal short-cut cytoplasmic AFs and actin aggregates in the cpb mutant NCs was proffered, along with a discussion of the reasons for 'dumpless' phenotype formation in the mutants.

  7. PreImplantation factor (PIF*) regulates systemic immunity and targets protective regulatory and cytoskeleton proteins.

    Science.gov (United States)

    Barnea, Eytan R; Hayrabedyan, Soren; Todorova, Krassimira; Almogi-Hazan, Osnat; Or, Reuven; Guingab, Joy; McElhinney, James; Fernandez, Nelson; Barder, Timothy

    2016-07-01

    Secreted by viable embryos, PIF is expressed by the placenta and found in maternal circulation. It promotes implantation and trophoblast invasion, achieving systemic immune homeostasis. Synthetic PIF successfully transposes endogenous PIF features to non-pregnant immune and transplant models. PIF affects innate and activated PBMC cytokines and genes expression. We report that PIF targets similar proteins in CD14+, CD4+ and CD8+ cells instigating integrated immune regulation. PIF-affinity chromatography followed by mass-spectrometry, pathway and heatmap analysis reveals that SET-apoptosis inhibitor, vimentin, myosin-9 and calmodulin are pivotal for immune regulation. PIF acts on macrophages down-stream of LPS (lipopolysaccharide-bacterial antigen) CD14/TLR4/MD2 complex, targeting myosin-9, thymosin-α1 and 14-3-3eta. PIF mainly targets platelet aggregation in CD4+, and skeletal proteins in CD8+ cells. Pathway analysis demonstrates that PIF targets and regulates SET, tubulin, actin-b, and S100 genes expression. PIF targets systemic immunity and has a short circulating half-life. Collectively, PIF targets identified; protective, immune regulatory and cytoskeleton proteins reveal mechanisms involved in the observed efficacy against immune disorders. Copyright © 2016 Elsevier GmbH. All rights reserved.

  8. Cytoskeleton reorganization and ultrastructural damage induced by gliadin in a three-dimensional in vitro model

    Institute of Scientific and Technical Information of China (English)

    Ersilia Dolfini; Leda Roncoroni; Luca Elli; Chiara Fumagalli; Roberto Colombo; Simona Ramponi; Fabio Forlani; Maria Teresa Bardella

    2005-01-01

    AIM: To evaluate the interplay between gliadin and LoVo cells and the direct effect of gliadin on cytoskeletal patterns.METHODS: We treated LoVo multicellular spheroids with digested bread wheat gliadin in order to investigate their morphology and ultrastructure (by means of light microscopy and scanning electron microscopy), and the effect of gliadin on actin (phalloidin fluorescence)and the tight-junction protein occludin and zonula occluden-1.RESULTS: The treated spheroids had deep holes and surface blebs, whereas the controls were smoothly surfaced ovoids. The incubation of LoVo spheroids with gliadin decreased the number of intracellular actin filaments, impaired and disassembled the integrity of the tight-junction system.CONCLUSION: Our data obtained from an "in vivolike" polarized culture system confirm the direct noxious effect of gliadin on the cytoskeleton and tight junctions of epithelial cells. Unlike two-dimensional cell culture systems, the use of multicellular spheroids seems to provide a suitable model for studying cell-cell interactions.

  9. Molecular architecture of synaptic actin cytoskeleton in hippocampal neurons reveals a mechanism of dendritic spine morphogenesis.

    Science.gov (United States)

    Korobova, Farida; Svitkina, Tatyana

    2010-01-01

    Excitatory synapses in the brain play key roles in learning and memory. The formation and functions of postsynaptic mushroom-shaped structures, dendritic spines, and possibly of presynaptic terminals, rely on actin cytoskeleton remodeling. However, the cytoskeletal architecture of synapses remains unknown hindering the understanding of synapse morphogenesis. Using platinum replica electron microscopy, we characterized the cytoskeletal organization and molecular composition of dendritic spines, their precursors, dendritic filopodia, and presynaptic boutons. A branched actin filament network containing Arp2/3 complex and capping protein was a dominant feature of spine heads and presynaptic boutons. Surprisingly, the spine necks and bases, as well as dendritic filopodia, also contained a network, rather than a bundle, of branched and linear actin filaments that was immunopositive for Arp2/3 complex, capping protein, and myosin II, but not fascin. Thus, a tight actin filament bundle is not necessary for structural support of elongated filopodia-like protrusions. Dynamically, dendritic filopodia emerged from densities in the dendritic shaft, which by electron microscopy contained branched actin network associated with dendritic microtubules. We propose that dendritic spine morphogenesis begins from an actin patch elongating into a dendritic filopodium, which tip subsequently expands via Arp2/3 complex-dependent nucleation and which length is modulated by myosin II-dependent contractility.

  10. Spatial modeling of vesicle transport and the cytoskeleton: the challenge of hitting the right road.

    Directory of Open Access Journals (Sweden)

    Michael Klann

    Full Text Available The membrane trafficking machinery provides a transport and sorting system for many cellular proteins. We propose a mechanistic agent-based computer simulation to integrate and test the hypothesis of vesicle transport embedded into a detailed model cell. The method tracks both the number and location of the vesicles. Thus both the stochastic properties due to the low numbers and the spatial aspects are preserved. The underlying molecular interactions that control the vesicle actions are included in a multi-scale manner based on the model of Heinrich and Rapoport (2005. By adding motor proteins we can improve the recycling process of SNAREs and model cell polarization. Our model also predicts that coat molecules should have a high turnover at the compartment membranes, while the turnover of motor proteins has to be slow. The modular structure of the underlying model keeps it tractable despite the overall complexity of the vesicle system. We apply our model to receptor-mediated endocytosis and show how a polarized cytoskeleton structure leads to polarized distributions in the plasma membrane both of SNAREs and the Ste2p receptor in yeast. In addition, we can couple signal transduction and membrane trafficking steps in one simulation, which enables analyzing the effect of receptor-mediated endocytosis on signaling.

  11. Androgens Regulate T47D Cells Motility and Invasion through Actin Cytoskeleton Remodeling

    Science.gov (United States)

    Montt-Guevara, Maria Magdalena; Shortrede, Jorge Eduardo; Giretti, Maria Silvia; Giannini, Andrea; Mannella, Paolo; Russo, Eleonora; Genazzani, Alessandro David; Simoncini, Tommaso

    2016-01-01

    The relationship between androgens and breast cancer is controversial. Androgens have complex effects on breast cancer progression and metastasis. Moreover, androgen receptor (AR) is expressed in approximately 70 to 90% of invasive breast carcinomas, which has prognostic relevance in basal-like cancers and in triple-negative breast cancers. Recent studies have associated the actin-binding proteins of the ezrin–radixin–moesin (ERM) family with metastasis in endocrine-sensitive cancers. We studied on T47D breast cancer cells whether androgens with different characteristics, such as testosterone (T), dihydrotestosterone (DHT), and dehydroepiandrosterone (DHEA) may regulate breast cancer cell motility and invasion through the control of actin remodeling. We demonstrate that androgens promote migration and invasion in T47D via Moesin activation. We show that T and DHEA exert their actions via the AR and estrogen receptor (ER), while the non-aromatizable androgen – DHT – only recruits AR. We further report that androgen induced significant changes in actin organization with pseudopodia along with membrane ruffles formation, and this process is mediated by Moesin. Our work identifies novel mechanisms of action of androgens on breast cancer cells. Through the modulation of Moesin, androgens alter the architecture of cytoskeleton in T47D breast cancer cell and promote cell migration and invasion. These results could help to understand the biological actions of androgens on breast cancer and, eventually, to develop new strategies for breast cancer treatment. PMID:27746764

  12. Oryzalin-modified disruption of microtubular cytoskeleton in Arabidopsis thaliana root cells under clinorotation

    Science.gov (United States)

    Kalinina, Ia.; Shevchenko, G.; Kordyum, E.

    There are data on gravisensitivity of cells not specialized to perceive a gravity vector but the molecular processes by which gravity affects not graviperceptive cells are still unclear Spaceflight experiments show that the microtubule self-organization in vitro is gravity-dependent Confocal microscopic analysis of the microtubule spatial organization under altered gravity with combination of approach drugs that disrupt normal microtubule behavior should give us a better understanding of the possible role of microtubule cytoskeleton in gravisensing on cellular level With this aim we examined influence of horizontal clinorotation 2 rpm on the spatial organization of microtubules in the root cortical and epidermal cells by means of LSM 5 PASCAL Zeiss Germany Microtubules were visualized by using stably transformed line of transgenic Arabidopsis thaliana expressing a green fluorescent protein-MAP4 fusion protein We inhibited microtubule function applying 5 956 M L oryzalin microtubule inhibitor in control and clinorotated seedlings Preliminary investigations show that cortical microtubule arrays were dense and predominantly transverse to the root long axis in the meristem and distal elongation zone in control and they got oblique direction when rapid cell elongation is finishing In the differentiation zone microtubules reorient with respect to the longitudinal growth axis of cell Under clinorotation cortical microtubules have the same configuration in the meristem central elongation zone and differentiation zone but it is observed appearances of several

  13. Rearrangement of actin cytoskeleton mediates invasion of Lotus japonicus roots by Mesorhizobium loti.

    Science.gov (United States)

    Yokota, Keisuke; Fukai, Eigo; Madsen, Lene H; Jurkiewicz, Anna; Rueda, Paloma; Radutoiu, Simona; Held, Mark; Hossain, Md Shakhawat; Szczyglowski, Krzysztof; Morieri, Giulia; Oldroyd, Giles E D; Downie, J Allan; Nielsen, Mette W; Rusek, Anna Maria; Sato, Shusei; Tabata, Satoshi; James, Euan K; Oyaizu, Hiroshi; Sandal, Niels; Stougaard, Jens

    2009-01-01

    Infection thread-dependent invasion of legume roots by rhizobia leads to internalization of bacteria into the plant cells, which is one of the salient features of root nodule symbiosis. We found that two genes, Nap1 (for Nck-associated protein 1) and Pir1 (for 121F-specific p53 inducible RNA), involved in actin rearrangements were essential for infection thread formation and colonization of Lotus japonicus roots by its natural microsymbiont, Mesorhizobium loti. nap1 and pir1 mutants developed an excess of uncolonized nodule primordia, indicating that these two genes were not essential for the initiation of nodule organogenesis per se. However, both the formation and subsequent progression of infection threads into the root cortex were significantly impaired in these mutants. We demonstrate that these infection defects were due to disturbed actin cytoskeleton organization. Short root hairs of the mutants had mostly transverse or web-like actin filaments, while bundles of actin filaments in wild-type root hairs were predominantly longitudinal. Corroborating these observations, temporal and spatial differences in actin filament organization between wild-type and mutant root hairs were also observed after Nod factor treatment, while calcium influx and spiking appeared unperturbed. Together with various effects on plant growth and seed formation, the nap1 and pir1 alleles also conferred a characteristic distorted trichome phenotype, suggesting a more general role for Nap1 and Pir1 in processes establishing cell polarity or polar growth in L. japonicus.

  14. Cytoplasmic streaming in Drosophila oocytes varies with kinesin activity and correlates with the microtubule cytoskeleton architecture.

    Science.gov (United States)

    Ganguly, Sujoy; Williams, Lucy S; Palacios, Isabel M; Goldstein, Raymond E

    2012-09-18

    Cells can localize molecules asymmetrically through the combined action of cytoplasmic streaming, which circulates their fluid contents, and specific anchoring mechanisms. Streaming also contributes to the distribution of nutrients and organelles such as chloroplasts in plants, the asymmetric position of the meiotic spindle in mammalian embryos, and the developmental potential of the zygote, yet little is known quantitatively about the relationship between streaming and the motor activity which drives it. Here we use Particle Image Velocimetry to quantify the statistical properties of Kinesin-dependent streaming during mid-oogenesis in Drosophila. We find that streaming can be used to detect subtle changes in Kinesin activity and that the flows reflect the architecture of the microtubule cytoskeleton. Furthermore, based on characterization of the rheology of the cytoplasm in vivo, we establish estimates of the number of Kinesins required to drive the observed streaming. Using this in vivo data as the basis of a model for transport, we suggest that the disordered character of transport at mid-oogenesis, as revealed by streaming, is an important component of the localization dynamics of the body plan determinant oskar mRNA.

  15. Role of cytoskeleton in cytokine production from lung alveolar epithelial cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Cytokines are involved in both host defense and inflammatory lung injury. Recent work from our laboratory and others has demonstrated that in addition to classical immune cells, lung alveolar epithelial cells (or pneumocytes) can also produce cytokines in response to various stimuli. This new knowledge has advanced our view of the host defense system in the lung. The regulatory mechanisms of cytokine production have been studied in great detail at various cellular and molecular levels, but the mechanisms of intracellular cytokine transport are largely unknown. Our recent studies suggest that the cytoskeleton could play an important role in mediating intracellular cytokine trafficking. This could be an important regulatory step for cytokine production. For example, lipopolyssacharide (LPS) induced tumor necrosis factor-α (TNF-α) from rat pneumocytes, which was further enhanced by a microfilament-disrupting agent. LPS also induced macrophage inflammatory protein-2(MIP-2), a chemokine for neutrophil recruitment and activation, from rat pneumocytes. This effect was enhanced by microtubule-disrupting agents. We speculate that both microfilaments and microtubules are involved in regulating cytokine transportation in pneumocytes through different mechanisms. Further investigation in on going in my laboratory. From a clinical perspective, if we understand the mechanisms regulating cytokine production and release from lung alveolar epithelial cells, we may be able to enhance or inhibit release of crucial cytokines depending on the clinical situation.

  16. ANDROGENS REGULATE T47D CELLS MOTILITY AND INVASION THROUGH ACTIN CYTOSKELETON REMODELLING

    Directory of Open Access Journals (Sweden)

    Maria Magdalena Montt-Guevara

    2016-09-01

    Full Text Available The relationship between androgens and breast cancer is controversial. Androgens have complex effects on breast cancer progression and metastasis. Moreover, androgens receptor (AR is expressed in approximately 70% to 90% of invasive breast carcinomas, which has prognostic relevance in basal-like cancers and in triple negative breast cancers. Recent studies have associated the actin-binding proteins of the Ezrin-Radixin-Moesin (ERM family with metastasis in endocrine-sensitive cancers. We studied on T47D breast cancer cells whether androgens with different characteristics, such as testosterone (T, dihydrotestosterone (DHT and dehydroepiandrosterone (DHEA may regulate breast cancer cell motility and invasion through the control of actin remodelling. We demonstrate that androgens promote migration and invasion in T47D via Moesin activation. We show that T and DHEA exert their actions via the AR and estrogen receptor (ER, while the non aromatizable androgen – DHT only recruits AR. We further report that androgen induced significant changes in actin organization with pseudopodia along with membrane ruffles formation, and this process is mediated by Moesin. Our work identifies novel mechanisms of action of androgens on breast cancer cells. Through the modulation of Moesin, androgens alter the architecture of cytoskeleton in T47D breast cancer cell and promote cell migration and invasion. These results could help to understand the biological actions of androgens on breast cancer, and eventually to develop new strategies for treatment of breast cancer.

  17. Product Platform Screening at LEGO

    DEFF Research Database (Denmark)

    Mortensen, Niels Henrik; Steen Jensen, Thomas; Nielsen, Ole Fiil

    2012-01-01

    Product platforms offer great benefits to companies developing new products in highly competitive markets. Literature describes how a single platform can be designed from a technical point of view, but rarely mentions how the process begins. How do companies identify possible platform candidates......, and how do they assess if these candidates have enough potential to be worth implementing? Danish toy manufacturer LEGO has systematically gone through this process twice. The first time the results were poor; almost all platform candidates failed. The second time, though, has been largely successful...... after a few changes had been applied to the initial process layout. This case study shows how companies must focus on a limited selection of simultaneous projects in order to keep focus. Primary stakeholders must be involved from the very beginning, and short presentations of the platform concepts...

  18. ADAPTABLE ALTERNATE REALITY GAMES PLATFORM

    Directory of Open Access Journals (Sweden)

    Liviu-Adrian Cotfas

    2013-12-01

    Full Text Available In this paper, we present an alternate reality games platform that facilitates the creation of ARG projects with different themes and sizes. The platform is well integrated with the most important social media networks, thus facilitating both the involvement of the public and the creation of a more engaging interaction for the participants. A cloud-based architecture was used in order to allow the platform to easily accommodate projects of various sizes and to provide a good level of scalability. The platform is fully localizable in any language and multiple languages can be used at once to create projects that target users from different countries. An initial project that uses gamification to create an immersive learning environment has been created around the developed platform. The project combines professional and public feedback in order to provide an enhanced learning experience.

  19. Regulation of the actin cytoskeleton in Helicobacter pylori-induced migration and invasive growth of gastric epithelial cells

    Directory of Open Access Journals (Sweden)

    Rieder Gabriele

    2011-11-01

    Full Text Available Abstract Dynamic rearrangement of the actin cytoskeleton is a significant hallmark of Helicobacter pylori (H. pylori infected gastric epithelial cells leading to cell migration and invasive growth. Considering the cellular mechanisms, the type IV secretion system (T4SS and the effector protein cytotoxin-associated gene A (CagA of H. pylori are well-studied initiators of distinct signal transduction pathways in host cells targeting kinases, adaptor proteins, GTPases, actin binding and other proteins involved in the regulation of the actin lattice. In this review, we summarize recent findings of how H. pylori functionally interacts with the complex signaling network that controls the actin cytoskeleton of motile and invasive gastric epithelial cells.

  20. The formin DIAPH1 (mDia1) regulates megakaryocyte proplatelet formation by remodeling the actin and microtubule cytoskeletons.

    Science.gov (United States)

    Pan, Jiajia; Lordier, Larissa; Meyran, Deborah; Rameau, Philippe; Lecluse, Yann; Kitchen-Goosen, Susan; Badirou, Idinath; Mokrani, Hayat; Narumiya, Shuh; Alberts, Arthur S; Vainchenker, William; Chang, Yunhua

    2014-12-18

    Megakaryocytes are highly specialized precursor cells that produce platelets via cytoplasmic extensions called proplatelets. Proplatelet formation (PPF) requires profound changes in microtubule and actin organization. In this work, we demonstrated that DIAPH1 (mDia1), a mammalian homolog of Drosophila diaphanous that works as an effector of the small GTPase Rho, negatively regulates PPF by controlling the dynamics of the actin and microtubule cytoskeletons. Moreover, we showed that inhibition of both DIAPH1 and the Rho-associated protein kinase (Rock)/myosin pathway increased PPF via coordination of both cytoskeletons. We provide evidence that 2 major effectors of the Rho GTPase pathway (DIAPH1 and Rock/myosin II) are involved not only in Rho-mediated stress fibers assembly, but also in the regulation of microtubule stability and dynamics during PPF.

  1. Effects of nitrogen ion implantation on lily pollen germination and the distribution of the actin cytoskeleton during pollen germination

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The effects of low energy nitrogen ion implantation on lily (Lilium davidii Duch.) pollen germination and the distribution of the actin cytoskeleton during pollen germination have been studied. Preliminary results showed that the ratio of pollen germination increased from (16.0±1.6)% to (27.0±2.1)% when implanted with nitrogen ions by 100 keV and a dose of 1013 ions/cm2. Further experiments were performed by staining the actin filaments in pollen with rhodamine-phalloidin and detected by using laser confocol microscopy. After hydration for 10 h, the actin filaments in ion implanted pollen grains tended to form thick bundles oriented in parallel or ring shape at the germinal furrow, indicating that the effect of nitrogen ion implantation on the germination of pollen might be mediated by reorganization of the actin cytoskeleton.

  2. Spatial Organization of the Cytoskeleton enhances Cargo Delivery to Specific Target Areas on the Plasma Membrane of Spherical Cells

    CERN Document Server

    Hafner, Anne E

    2016-01-01

    Intracellular transport is vital for the proper functioning and survival of a cell. Cargo (proteins, vesicles, organelles, etc.) is transferred from its place of creation to its target locations via molecular motor assisted transport along cytoskeletal filaments. The transport efficiency is strongly affected by the spatial organization of the cytoskeleton, which constitutes an inhomogeneous, complex network. In cells with a centrosome microtubules grow radially from the central microtubule organizing center towards the cell periphery whereas actin filaments form a dense meshwork, the actin cortex, underneath the cell membrane with a broad range of orientations. The emerging ballistic motion along filaments is frequently interrupted due to constricting intersection nodes or cycles of detachment and reattachment processes in the crowded cytoplasm. In order to investigate the efficiency of search strategies established by the cell's specific spatial organization of the cytoskeleton we formulate a random velocity...

  3. Comparison and evaluation of immobilization methods for preparing bacterial probes using acidophilic bioleaching bacteria Acidithiobacillus thiooxidans for AFM studies.

    Science.gov (United States)

    Diao, Mengxue; Taran, Elena; Mahler, Stephen M; Nguyen, Anh V

    2014-07-01

    We evaluated different strategies for constructing bacterial probes for atomic force microscopy studies of bioleaching Acidithiobacillus thiooxidans interacting with pyrite mineral surfaces. Of three available techniques, the bacterial colloidal probe technique is the most reliable and provides a versatile platform for quantifying true interactive forces between bioleaching microorganisms and mineral surfaces.

  4. Paper based electronics platform

    KAUST Repository

    Nassar, Joanna Mohammad

    2017-07-20

    A flexible and non-functionalized low cost paper-based electronic system platform fabricated from common paper, such as paper based sensors, and methods of producing paper based sensors, and methods of sensing using the paper based sensors are provided. A method of producing a paper based sensor can include the steps of: a) providing a conventional paper product to serve as a substrate for the sensor or as an active material for the sensor or both, the paper product not further treated or functionalized; and b) applying a sensing element to the paper substrate, the sensing element selected from the group consisting of a conductive material, the conductive material providing contacts and interconnects, sensitive material film that exhibits sensitivity to pH levels, a compressible and/or porous material disposed between a pair of opposed conductive elements, or a combination of two of more said sensing elements. The method of sensing can further include measuring, using the sensing element, a change in resistance, a change in voltage, a change in current, a change in capacitance, or a combination of any two or more thereof.

  5. The Dynamic Pollen Tube Cytoskeleton: Live Cell Studies Using Actin-Binding and Microtubule-Binding Reporter Proteins

    Institute of Scientific and Technical Information of China (English)

    Alice Y. Cheung; Qiao-hong Duan; Silvia Santos Costa; Barend H.J.de Graaf; Veronica S.Di Stilio; Jose Feijo; Hen-Ming Wu

    2008-01-01

    Pollen tubes elongate within the pistil to transport sperm cells to the embryo sac for fertilization.Growth occurs exclusively at the tube apex,rendering pollen tube elongation a most dramatic polar cell growth process.A hall-mark pollen tube feature is its cytoskeleton,which comprises elaborately organized and dynamic actin microfilaments and microtubules.Pollen tube growth is dependent on the actin cytoskeleton;its organization and regulation have been exalined extensively by various approaches.including fluorescent protein labeled actin-binding proteins in live cell studies.Using the previously described GFP-NtADF1 and GFP-LIADF1, and a new actin reporter protein NtPLIM2b-GFP,we re-affirm that the predominant actin structures in elongating tobacco and lily pollen tubes are long,streaming actin cables along the pollen tube shank,and a subapical structure comprising shorter actin cables.The subapical collection of actin microfilaments undergoes dynamic changes,giving rise to the appearance of structures that range from basket-or funnel-shaped,mesh-like to a subtle ring.NtPLIM2b-GFP is used in combination with a guanine nucleotide exchange factor for the Rho GTPases,AtROP-GEF1,to illustrate the use of these actin reporter proteins to explore the linkage between the polar cell growth process and its actin cytoskeleton.Contrary to the actin cytoskeleton,microtubules appear not to play a direct role in supporting the polar cell growth process in angiosperm pollen tubes.Using a microtubule reporter protein based on the microtubule end-binding protein from Arabidopsis AtEB1,GFP-AtEB1,we show that the extensive microtubule network in elongating pollen tubes displays varying degrees of dynamics.These reporter proteins provide versatile tools to explore the functional connection between major structural and signaling components of the polar pollen tube growth process.

  6. Calpain-controlled detachment of major glycoproteins from the cytoskeleton regulates adhesive properties of activated phosphatidylserine-positive platelets.

    Science.gov (United States)

    Artemenko, Elena O; Yakimenko, Alena O; Pichugin, Alexey V; Ataullakhanov, Fazly I; Panteleev, Mikhail A

    2016-02-15

    In resting platelets, adhesive membrane glycoproteins are attached to the cytoskeleton. On strong activation, phosphatidylserine(PS)-positive and -negative platelet subpopulations are formed. Platelet activation is accompanied by cytoskeletal rearrangement, although the glycoprotein attachment status in these two subpopulations is not clear. We developed a new, flow cytometry-based, single-cell approach to investigate attachment of membrane glycoproteins to the cytoskeleton in cell subpopulations. In PS-negative platelets, adhesive glycoproteins integrin αIIbβ3, glycoprotein Ib and, as shown for the first time, P-selectin were associated with the cytoskeleton. In contrast, this attachment was disrupted in PS-positive platelets; it was retained to some extent only in the small convex regions or 'caps'. It correlated with the degradation of talin and filamin observed only in PS-positive platelets. Calpain inhibitors essentially prevented the disruption of membrane glycoprotein attachment in PS-positive platelets, as well as talin and filamin degradation. With the suggestion that detachment of glycoproteins from the cytoskeleton may affect platelet adhesive properties, we investigated the ability of PS-positive platelets to resist shear-induced breakaway from the immobilized fibrinogen. Shear rates of 500/s caused PS-positive platelet breakaway, but their adhesion stability increased more than 10-fold after pretreatment of the platelets with calpain inhibitor. In contrast, the ability of PS-positive platelets to adhere to immobilized von Willebrand's factor at 100/s was low, but this was not affected by the preincubation of platelets with a calpain inhibitor. Our data suggest that calpain-controlled detachment of membrane glycoproteins is a new mechanism that is responsible for the loss of ability of the procoagulant platelets to resist detachment from thrombi by high shear stress.

  7. Effects of polyamines and calcium and sodium ions on smooth muscle cytoskeleton-associated phosphatidylinositol (4)-phosphate 5-kinase.

    Science.gov (United States)

    Chen, H; Baron, C B; Griffiths, T; Greeley, P; Coburn, R F

    1998-10-01

    In many different cell types, including smooth muscle cells (Baron et al., 1989, Am. J. Physiol., 256: C375-383; Baron et al., J. Pharmacol. Exp. Ther. 266: 8-15), phosphatidylinositol (4)-phosphate 5-kinase plays a critical role in the regulation of membrane concentrations of phosphatidylinositol (4,5)-bisphosphate and formation of inositol (1,4,5)-trisphosphate. In unstimulated porcine trachealis smooth muscle, 70% of total cellular phosphatidylinositol (4)-phosphate 5-kinase activity was associated with cytoskeletal proteins and only trace activity was detectable in isolated sarcolemma. Using two different preparations, we studied cytoskeleton-associated phosphatidyl inositol (4)-phosphate 5-kinase under conditions that attempted to mimic the ionic and thermal cytoplasmic environment of living cells. The cytoskeleton-associated enzyme, studied using phosphatidylinositol (4)-phosphate substrate concentrations that produced phosphatidylinositol 4,5-bisphosphate at about 10% of the maximal rate, was sensitive to free [Mg2+], had an absolute requirement for phosphatidylserine, phosphatidic acid, or phosphatidylinositol, and included type I isoforms. At 0.5 mM free [Mg2+], physiological spermine concentrations, 0.2-0.4 mM, increased phosphatidylinositol (4)-phosphate 5-kinase activity two to four times compared to controls run without spermine. The EC50 for spermine-evoked increases in activity was 0.17 +/- 0.02 mM. Spermine-evoked enzyme activity was a function of both free [Mg2+] and substrate concentration. Cytoskeleton-associated phosphatidylinositol (4)-phosphate 5-kinase was inhibited by free [Ca2+] over a physiological range for cytoplasm--10(-8) to 10(-5) M, an effect independent of the presence of calmodulin. Na+ over the range 20 to 50 mM also inhibited this enzyme activated by 5 mM Mg2+ but had no effect on spermine-activated enzyme. Na+, Ca2+, and spermine appear to be physiological modulators of smooth muscle cytoskeleton-bound phosphatidylinositol (4

  8. [An inhibitory analysis of the role of the enterocyte cytoskeleton in the absorption of food substances in the small intestine].

    Science.gov (United States)

    Morozov, I A; Verina, T Iu

    1993-06-01

    The effect of colchicine and cytochalasin B and D on the process of glucose and plant oil absorption in the small intestine of rats was studied using the light and electron microscopy and biochemical methods. The colchicine and CB, CD action on the elements of enterocytes' apical contractile complex and cytoskeleton inhibited the absorption thus suggesting the major role of endocytosis in the process of nutrients absorption in the small intestine.

  9. Plat_Forms -- a contest: The web development platform comparison

    CERN Document Server

    Prechelt, Lutz

    2008-01-01

    "Plat_Forms" is a competition in which top-class teams of three programmers compete to implement the same requirements for a web-based system within 30 hours, each team using a different technology platform (Java EE, .NET, PHP, Perl, Python, or Ruby on Rails). The results will provide new insights into the real (rather than purported) pros, cons, and emergent properties of each platform. The evaluation will analyze many aspects of each solution, both external (usability, functionality, reliability, performance, etc.) and internal (structure, understandability, flexibility, etc.).

  10. The Cytoskeleton and the Peroxisomal-Targeted SNOWY COTYLEDON3 Protein Are Required for Chloroplast Development in Arabidopsis[W

    Science.gov (United States)

    Albrecht, Verónica; Šimková, Klára; Carrie, Chris; Delannoy, Etienne; Giraud, Estelle; Whelan, Jim; Small, Ian David; Apel, Klaus; Badger, Murray R.; Pogson, Barry James

    2010-01-01

    Here, we describe the snowy cotyledon3 (sco3-1) mutation, which impairs chloroplast and etioplast development in Arabidopsis thaliana seedlings. SCO3 is a member of a largely uncharacterized protein family unique to the plant kingdom. The sco3-1 mutation alters chloroplast morphology and development, reduces chlorophyll accumulation, impairs thylakoid formation and photosynthesis in seedlings, and results in photoinhibition under extreme CO2 concentrations in mature leaves. There are no readily apparent changes to chloroplast biology, such as transcription or assembly that explain the disruption to chloroplast biogenesis. Indeed, SCO3 is actually targeted to another organelle, specifically to the periphery of peroxisomes. However, impaired chloroplast development cannot be attributed to perturbed peroxisomal metabolic processes involving germination, fatty acid β-oxidation or photorespiration, though there are so far undescribed changes in low and high CO2 sensitivity in seedlings and young true leaves. Many of the chloroplasts are bilobed, and some have persistent membranous extensions that encircle other cellular components. Significantly, there are changes to the cytoskeleton in sco3-1, and microtubule inhibitors have similar effects on chloroplast biogenesis as sco3-1 does. The localization of SCO3 to the periphery of the peroxisomes was shown to be dependent on a functional microtubule cytoskeleton. Therefore, the microtubule and peroxisome-associated SCO3 protein is required for chloroplast development, and sco3-1, along with microtubule inhibitors, demonstrates an unexpected role for the cytoskeleton and peroxisomes in chloroplast biogenesis. PMID:20978221

  11. Girdin-mediated interactions between cadherin and the actin cytoskeleton are required for epithelial morphogenesis in Drosophila.

    Science.gov (United States)

    Houssin, Elise; Tepass, Ulrich; Laprise, Patrick

    2015-05-15

    E-cadherin-mediated cell-cell adhesion is fundamental for epithelial tissue morphogenesis, physiology and repair. E-cadherin is a core transmembrane constituent of the zonula adherens (ZA), a belt-like adherens junction located at the apicolateral border in epithelial cells. The anchorage of ZA components to cortical actin filaments strengthens cell-cell cohesion and allows for junction contractility, which shapes epithelial tissues during development. Here, we report that the cytoskeletal adaptor protein Girdin physically and functionally interacts with components of the cadherin-catenin complex during Drosophila embryogenesis. Fly Girdin is broadly expressed throughout embryonic development and enriched at the ZA in epithelial tissues. Girdin associates with the cytoskeleton and co-precipitates with the cadherin-catenin complex protein α-Catenin (α-Cat). Girdin mutations strongly enhance adhesion defects associated with reduced DE-cadherin (DE-Cad) expression. Moreover, the fraction of DE-Cad molecules associated with the cytoskeleton decreases in the absence of Girdin, thereby identifying Girdin as a positive regulator of adherens junction function. Girdin mutant embryos display isolated epithelial cell cysts and rupture of the ventral midline, consistent with defects in cell-cell cohesion. In addition, loss of Girdin impairs the collective migration of epithelial cells, resulting in dorsal closure defects. We propose that Girdin stabilizes epithelial cell adhesion and promotes morphogenesis by regulating the linkage of the cadherin-catenin complex to the cytoskeleton.

  12. Regulation of retinoschisin secretion in Weri-Rb1 cells by the F-actin and microtubule cytoskeleton.

    Directory of Open Access Journals (Sweden)

    Eiko Kitamura

    Full Text Available Retinoschisin is encoded by the gene responsible for X-linked retinoschisis (XLRS, an early onset macular degeneration that results in a splitting of the inner layers of the retina and severe loss in vision. Retinoschisin is predominantly expressed and secreted from photoreceptor cells as a homo-oligomer protein; it then associates with the surface of retinal cells and maintains the retina cellular architecture. Many missense mutations in the XLRS1 gene are known to cause intracellular retention of retinoschisin, indicating that the secretion process of the protein is a critical step for its normal function in the retina. However, the molecular mechanisms underlying retinoschisin's secretion remain to be fully elucidated. In this study, we investigated the role of the F-actin cytoskeleton in the secretion of retinoschisin by treating Weri-Rb1 cells, which are known to secrete retinoschisin, with cytochalasin D, jasplakinolide, Y-27632, and dibutyryl cGMP. Our results show that cytochalasin D and jasplakinolide inhibit retinoschisin secretion, whereas Y-27632 and dibutyryl cGMP enhance secretion causing F-actin alterations. We also demonstrate that high concentrations of taxol, which hyperpolymerizes microtubules, inhibit retinoschisin secretion. Our data suggest that retinoschisin secretion is regulated by the F-actin cytoskeleton, that cGMP or inhibition of ROCK alters F-actin structure enhancing the secretion, and that the microtubule cytoskeleton is also involved in this process.

  13. The Vip1 inositol polyphosphate kinase family regulates polarized growth and modulates the microtubule cytoskeleton in fungi.

    Directory of Open Access Journals (Sweden)

    Jennifer Pöhlmann

    2014-09-01

    Full Text Available Microtubules (MTs are pivotal for numerous eukaryotic processes ranging from cellular morphogenesis, chromosome segregation to intracellular transport. Execution of these tasks requires intricate regulation of MT dynamics. Here, we identify a new regulator of the Schizosaccharomyces pombe MT cytoskeleton: Asp1, a member of the highly conserved Vip1 inositol polyphosphate kinase family. Inositol pyrophosphates generated by Asp1 modulate MT dynamic parameters independent of the central +TIP EB1 and in a dose-dependent and cellular-context-dependent manner. Importantly, our analysis of the in vitro kinase activities of various S. pombe Asp1 variants demonstrated that the C-terminal phosphatase-like domain of the dual domain Vip1 protein negatively affects the inositol pyrophosphate output of the N-terminal kinase domain. These data suggest that the former domain has phosphatase activity. Remarkably, Vip1 regulation of the MT cytoskeleton is a conserved feature, as Vip1-like proteins of the filamentous ascomycete Aspergillus nidulans and the distantly related pathogenic basidiomycete Ustilago maydis also affect the MT cytoskeleton in these organisms. Consistent with the role of interphase MTs in growth zone selection/maintenance, all 3 fungal systems show aspects of aberrant cell morphogenesis. Thus, for the first time we have identified a conserved biological process for inositol pyrophosphates.

  14. Role of dystroglycan in limiting contraction-induced injury to the sarcomeric cytoskeleton of mature skeletal muscle.

    Science.gov (United States)

    Rader, Erik P; Turk, Rolf; Willer, Tobias; Beltrán, Daniel; Inamori, Kei-Ichiro; Peterson, Taylor A; Engle, Jeffrey; Prouty, Sally; Matsumura, Kiichiro; Saito, Fumiaki; Anderson, Mary E; Campbell, Kevin P

    2016-09-27

    Dystroglycan (DG) is a highly expressed extracellular matrix receptor that is linked to the cytoskeleton in skeletal muscle. DG is critical for the function of skeletal muscle, and muscle with primary defects in the expression and/or function of DG throughout development has many pathological features and a severe muscular dystrophy phenotype. In addition, reduction in DG at the sarcolemma is a common feature in muscle biopsies from patients with various types of muscular dystrophy. However, the consequence of disrupting DG in mature muscle is not known. Here, we investigated muscles of transgenic mice several months after genetic knockdown of DG at maturity. In our study, an increase in susceptibility to contraction-induced injury was the first pathological feature observed after the levels of DG at the sarcolemma were reduced. The contraction-induced injury was not accompanied by increased necrosis, excitation-contraction uncoupling, or fragility of the sarcolemma. Rather, disruption of the sarcomeric cytoskeleton was evident as reduced passive tension and decreased titin immunostaining. These results reveal a role for DG in maintaining the stability of the sarcomeric cytoskeleton during contraction and provide mechanistic insight into the cause of the reduction in strength that occurs in muscular dystrophy after lengthening contractions.

  15. The Vip1 inositol polyphosphate kinase family regulates polarized growth and modulates the microtubule cytoskeleton in fungi.

    Science.gov (United States)

    Pöhlmann, Jennifer; Risse, Carmen; Seidel, Constanze; Pohlmann, Thomas; Jakopec, Visnja; Walla, Eva; Ramrath, Pascal; Takeshita, Norio; Baumann, Sebastian; Feldbrügge, Michael; Fischer, Reinhard; Fleig, Ursula

    2014-09-01

    Microtubules (MTs) are pivotal for numerous eukaryotic processes ranging from cellular morphogenesis, chromosome segregation to intracellular transport. Execution of these tasks requires intricate regulation of MT dynamics. Here, we identify a new regulator of the Schizosaccharomyces pombe MT cytoskeleton: Asp1, a member of the highly conserved Vip1 inositol polyphosphate kinase family. Inositol pyrophosphates generated by Asp1 modulate MT dynamic parameters independent of the central +TIP EB1 and in a dose-dependent and cellular-context-dependent manner. Importantly, our analysis of the in vitro kinase activities of various S. pombe Asp1 variants demonstrated that the C-terminal phosphatase-like domain of the dual domain Vip1 protein negatively affects the inositol pyrophosphate output of the N-terminal kinase domain. These data suggest that the former domain has phosphatase activity. Remarkably, Vip1 regulation of the MT cytoskeleton is a conserved feature, as Vip1-like proteins of the filamentous ascomycete Aspergillus nidulans and the distantly related pathogenic basidiomycete Ustilago maydis also affect the MT cytoskeleton in these organisms. Consistent with the role of interphase MTs in growth zone selection/maintenance, all 3 fungal systems show aspects of aberrant cell morphogenesis. Thus, for the first time we have identified a conserved biological process for inositol pyrophosphates.

  16. Spatial organization of the cytoskeleton enhances cargo delivery to specific target areas on the plasma membrane of spherical cells

    Science.gov (United States)

    Hafner, Anne E.; Rieger, Heiko

    2016-12-01

    Intracellular transport is vital for the proper functioning and survival of a cell. Cargo (proteins, vesicles, organelles, etc) is transferred from its place of creation to its target locations via molecular motor assisted transport along cytoskeletal filaments. The transport efficiency is strongly affected by the spatial organization of the cytoskeleton, which constitutes an inhomogeneous, complex network. In cells with a centrosome microtubules grow radially from the central microtubule organizing center towards the cell periphery whereas actin filaments form a dense meshwork, the actin cortex, underneath the cell membrane with a broad range of orientations. The emerging ballistic motion along filaments is frequently interrupted due to constricting intersection nodes or cycles of detachment and reattachment processes in the crowded cytoplasm. In order to investigate the efficiency of search strategies established by the cell’s specific spatial organization of the cytoskeleton we formulate a random velocity model with intermittent arrest states. With extensive computer simulations we analyze the dependence of the mean first passage times for narrow escape problems on the structural characteristics of the cytoskeleton, the motor properties and the fraction of time spent in each state. We find that an inhomogeneous architecture with a small width of the actin cortex constitutes an efficient intracellular search strategy.

  17. Platform projections, compilers, interpreters and portability

    NARCIS (Netherlands)

    Bergstra, J.A.; Loots, M.E.

    1999-01-01

    Platform projection semantics extends projection semantics by means of the encapsulation of a processor used for program execution. Platform projection semantics abstracts from platform specific details. For a given program its platform projection semantics may be platform-independent. Two forms

  18. Hard Probes at ATLAS

    CERN Document Server

    Citron, Z; The ATLAS collaboration

    2014-01-01

    The ATLAS collaboration has measured several hard probe observables in Pb+Pb and p+Pb collisions at the LHC. These measurements include jets which show modification in the hot dense medium of heavy ion collisions as well as color neutral electro-weak bosons. Together, they elucidate the nature of heavy ion collisions.

  19. Endocavity Ultrasound Probe Manipulators.

    Science.gov (United States)

    Stoianovici, Dan; Kim, Chunwoo; Schäfer, Felix; Huang, Chien-Ming; Zuo, Yihe; Petrisor, Doru; Han, Misop

    2013-06-01

    We developed two similar structure manipulators for medical endocavity ultrasound probes with 3 and 4 degrees of freedom (DoF). These robots allow scanning with ultrasound for 3-D imaging and enable robot-assisted image-guided procedures. Both robots use remote center of motion kinematics, characteristic of medical robots. The 4-DoF robot provides unrestricted manipulation of the endocavity probe. With the 3-DoF robot the insertion motion of the probe must be adjusted manually, but the device is simpler and may also be used to manipulate external-body probes. The robots enabled a novel surgical approach of using intraoperative image-based navigation during robot-assisted laparoscopic prostatectomy (RALP), performed with concurrent use of two robotic systems (Tandem, T-RALP). Thus far, a clinical trial for evaluation of safety and feasibility has been performed successfully on 46 patients. This paper describes the architecture and design of the robots, the two prototypes, control features related to safety, preclinical experiments, and the T-RALP procedure.

  20. One-Probe Search

    DEFF Research Database (Denmark)

    Östlin, Anna; Pagh, Rasmus

    2002-01-01

    We consider dictionaries that perform lookups by probing a single word of memory, knowing only the size of the data structure. We describe a randomized dictionary where a lookup returns the correct answer with probability 1 - e, and otherwise returns don't know. The lookup procedure uses an expan...

  1. Probing the Solar System

    Science.gov (United States)

    Wilkinson, John

    2013-01-01

    Humans have always had the vision to one day live on other planets. This vision existed even before the first person was put into orbit. Since the early space missions of putting humans into orbit around Earth, many advances have been made in space technology. We have now sent many space probes deep into the Solar system to explore the planets and…

  2. One-Probe Search

    DEFF Research Database (Denmark)

    Östlin, Anna; Pagh, Rasmus

    2002-01-01

    We consider dictionaries that perform lookups by probing a single word of memory, knowing only the size of the data structure. We describe a randomized dictionary where a lookup returns the correct answer with probability 1 - e, and otherwise returns don't know. The lookup procedure uses an expan...

  3. Probing the Solar System

    Science.gov (United States)

    Wilkinson, John

    2013-01-01

    Humans have always had the vision to one day live on other planets. This vision existed even before the first person was put into orbit. Since the early space missions of putting humans into orbit around Earth, many advances have been made in space technology. We have now sent many space probes deep into the Solar system to explore the planets and…

  4. Measurement of cell respiration and oxygenation in standard multichannel biochips using phosphorescent O2-sensitive probes.

    Science.gov (United States)

    Kondrashina, Alina V; Papkovsky, Dmitri B; Dmitriev, Ruslan I

    2013-09-07

    Measurement of cell oxygenation and oxygen consumption is useful for studies of cell bioenergetics, metabolism, mitochondrial function, drug toxicity and common pathophysiological conditions. Here we present a new platform for such applications which uses commercial multichannel biochips (μ-slides, Ibidi) and phosphorescent O2 sensitive probes. This platform was evaluated with both extracellular and intracellular O2 probes, several different cell types and treatments including mitochondrial uncoupling and inhibition, depletion of extracellular Ca(2+) and inhibition of V-ATPase and histone deacetylases. The results show that compared to the standard microwell plates currently used, the μ-slide platform provides facile O2 measurements with both suspension and adherent cells, higher sensitivity and reproducibility, and faster measurement time. It also allows re-perfusion and multiple treatments of cells and multi-parametric analyses in conjunction with other probes. Optical measurements are conducted on standard fluorescence readers and microscopes.

  5. Effect of lipid matrix and cytoskeleton proteins on Ca2+-activated K+ channels in erythrocytes of alcoholic and II type diabetes mellitus patients.

    Science.gov (United States)

    Prokop'eva, V D; Petrova, I V; Sitozhevskii, A V; Kremeno, S V; Koryukin, V I; Baskakov, M B; Bokhan, N A; Novitskii, V V

    2002-10-01

    We studied the effect of changes in erythrocyte volume and irreversible thermal denaturation of cytoskeleton proteins and lipid matrix on activity of Ca(2+)-activated K+ channels in erythrocytes of alcoholic and patients with II type diabetes mellitus. Changes in Ca(2+)-dependent potassium permeability of erythrocyte membrane in alcoholic patients and patients with II type diabetes mellitus are related to modification of cytoskeleton, rather than to changes in lipid matrix.

  6. Vertical Relationships within Platform Marketplaces

    Directory of Open Access Journals (Sweden)

    Mark J. Tremblay

    2016-07-01

    Full Text Available In two-sided markets a platform allows consumers and sellers to interact by creating sub-markets within the platform marketplace. For example, Amazon has sub-markets for all of the different product categories available on its site, and smartphones have sub-markets for different types of applications (gaming apps, weather apps, map apps, ridesharing apps, etc.. The network benefits between consumers and sellers depend on the mode of competition within the sub-markets: more competition between sellers lowers product prices, increases the surplus consumers receive from a sub-market, and makes platform membership more desirable for consumers. However, more competition also lowers profits for a seller which makes platform membership less desirable for a seller and reduces seller entry and the number of sub-markets available on the platform marketplace. This dynamic between seller competition within a sub-market and agents’ network benefits leads to platform pricing strategies, participation decisions by consumers and sellers, and welfare results that depend on the mode of competition. Thus, the sub-market structure is important when investigating platform marketplaces.

  7. Dissecting the Mechanisms of Doxorubicin and Oxidative Stress-Induced Cytotoxicity: The Involvement of Actin Cytoskeleton and ROCK1

    Science.gov (United States)

    Wei, Lei; Surma, Michelle; Gough, Gina; Shi, Stephanie; Lambert-Cheatham, Nathan; Chang, Jiang; Shi, Jianjian

    2015-01-01

    We have recently reported that ROCK1 deficiency in mouse embryonic fibroblasts (MEF) has superior anti-apoptotic and pro-survival effects than antioxidants against doxorubicin, a chemotherapeutic drug. Although oxidative stress is the most widely accepted mechanism, our studies suggest that ROCK1-dependent actin cytoskeleton remodeling plays a more important role in mediating doxorubicin cytotoxicity on MEFs. To further explore the contributions of ROCK1-dependent actin cytoskeleton remodeling in response to stress, this study investigates the mechanistic differences between the cytotoxic effects of doxorubicin versus hydrogen peroxide (H2O2), with a focus on cytoskeleton alterations, apoptosis and necrosis induction. We found that both types of stress induce caspase activation but with different temporal patterns and magnitudes in MEFs: H2O2 induces the maximal levels (2 to 4-fold) of activation of caspases 3, 8, and 9 within 4 h, while doxorubicin induces much higher maximal levels (15 to 25-fold) of caspases activation at later time points (16–24 h). In addition, necrosis induced by H2O2 reaches maximal levels within 4 h while doxorubicin-induced necrosis largely occurs at 16–24 h secondary to apoptosis. Moreover, both types of stress induce actin cytoskeleton remodeling but with different characteristics: H2O2 induces disruption of stress fibers associated with cytosolic translocation of phosphorylated myosin light chain (p-MLC) from stress fibers, while doxorubicin induces cortical F-actin formation associated with cortical translocation of p-MLC from central stress fibers. Furthermore, N-acetylcysteine (an antioxidant) is a potent suppressor for H2O2-induced cytotoxic effects including caspase activation, necrosis, and cell detachment, but shows a much reduced inhibition on doxorubicin-induced changes. On the other hand, ROCK1 deficiency is a more potent suppressor for the cytotoxic effects induced by doxorubicin than by H2O2. These results support the

  8. Platform decisions supported by gaming

    DEFF Research Database (Denmark)

    Hansen, Poul H. Kyvsgård; Mikkola, Juliana Hsuan

    2007-01-01

    Platform is an ambiguous multidisciplinary concept. The philosophy behind it is easy to communicate and makes intuitively sense. However, the ease in communication does overshadow the high complexity when the concept is implemented. The practical industrial platform implementation challenge can...... is the application of on-line games in order to provide training for decision makers and in order to generate overview over the implications of platform decisions. However, games have to be placed in a context with other methods and we argue that a mixture of games, workshops, and simulations can provide improved...

  9. EDITORIAL: Probing the nanoworld Probing the nanoworld

    Science.gov (United States)

    Miles, Mervyn

    2009-10-01

    In nanotechnology, it is the unique properties arising from nanometre-scale structures that lead not only to their technological importance but also to a better understanding of the underlying science. Over the last twenty years, material properties at the nanoscale have been dominated by the properties of carbon in the form of the C60 molecule, single- and multi-wall carbon nanotubes, nanodiamonds, and recently graphene. During this period, research published in the journal Nanotechnology has revealed the amazing mechanical properties of such materials as well as their remarkable electronic properties with the promise of new devices. Furthermore, nanoparticles, nanotubes, nanorods, and nanowires from metals and dielectrics have been characterized for their electronic, mechanical, optical, chemical and catalytic properties. Scanning probe microscopy (SPM) has become the main characterization technique and atomic force microscopy (AFM) the most frequently used SPM. Over the past twenty years, SPM techniques that were previously experimental in nature have become routine. At the same time, investigations using AFM continue to yield impressive results that demonstrate the great potential of this powerful imaging tool, particularly in close to physiological conditions. In this special issue a collaboration of researchers in Europe report the use of AFM to provide high-resolution topographical images of individual carbon nanotubes immobilized on various biological membranes, including a nuclear membrane for the first time (Lamprecht C et al 2009 Nanotechnology 20 434001). Other SPM developments such as high-speed AFM appear to be making a transition from specialist laboratories to the mainstream, and perhaps the same may be said for non-contact AFM. Looking to the future, characterisation techniques involving SPM and spectroscopy, such as tip-enhanced Raman spectroscopy, could emerge as everyday methods. In all these advanced techniques, routinely available probes will

  10. Lecithin Prevents Cortical Cytoskeleton Reorganization in Rat Soleus Muscle Fibers under Short-Term Gravitational Disuse.

    Science.gov (United States)

    Ogneva, Irina V; Biryukov, Nikolay S

    2016-01-01

    The aim of this study was to prevent the cortical cytoskeleton reorganization of rat soleus muscle fibers under short-term gravitational disuse. Once a day, we injected the right soleus muscle with 0.5 ml lecithin at a concentration of 200 mg/ml and the left soleus muscle with a diluted solution in an equal volume for 3 days prior to the experiment. To simulate microgravity conditions in rats, an anti-orthostatic suspension was used according to the Ilyin-Novikov method modified by Morey-Holton et al. for 6 hours. The following groups of soleus muscle tissues were examined: "C", "C+L", "HS", and "HS+L". The transversal stiffness of rat soleus muscle fibers after 6 hours of suspension did not differ from that of the control group for the corresponding legs; there were no differences between the groups without lecithin «C» and «HS» or between the groups with lecithin "C+L" and "HS+L". However, lecithin treatment for three days resulted in an increase in cell stiffness; in the "C+L" group, cell stiffness was significantly higher by 22.7% (p lecithin treatment: the beta-actin and gamma-actin mRNA content in group "C+L" increased by 200% compared with that of group "C", and beta-tubulin increased by 100% (as well as the mRNA content of tubulin-binding proteins Ckap5, Tcp1, Cct5 and Cct7). In addition, desmin mRNA content remained unchanged in all of the experimental groups. As a result of the lecithin injections, there was a redistribution of the mRNA content of genes encoding actin monomer- and filament-binding proteins in the direction of increasing actin polymerization and filament stability; the mRNA content of Arpc3 and Lcp1 increased by 3- and 5-fold, respectively, but the levels of Tmod1 and Svil decreased by 2- and 5-fold, respectively. However, gravitational disuse did not result in changes in the mRNA content of Arpc3, Tmod1, Svil or Lcp1. Anti-orthostatic suspension for 6 hours resulted in a decrease in the mRNA content of alpha-actinin-4 (Actn4) and

  11. Complexity of the tensegrity structure for dynamic energy and force distribution of cytoskeleton during cell spreading.

    Directory of Open Access Journals (Sweden)

    Ting-Jung Chen

    Full Text Available Cytoskeleton plays important roles in intracellular force equilibrium and extracellular force transmission from/to attaching substrate through focal adhesions (FAs. Numerical simulations of intracellular force distribution to describe dynamic cell behaviors are still limited. The tensegrity structure comprises tension-supporting cables and compression-supporting struts that represent the actin filament and microtubule respectively, and has many features consistent with living cells. To simulate the dynamics of intracellular force distribution and total stored energy during cell spreading, the present study employed different complexities of the tensegrity structures by using octahedron tensegrity (OT and cuboctahedron tensegrity (COT. The spreading was simulated by assigning specific connection nodes for radial displacement and attachment to substrate to form FAs. The traction force on each FA was estimated by summarizing the force carried in sounding cytoskeletal elements. The OT structure consisted of 24 cables and 6 struts and had limitations soon after the beginning of spreading by declining energy stored in struts indicating the abolishment of compression in microtubules. The COT structure, double the amount of cables and struts than the OT structure, provided sufficient spreading area and expressed similar features with documented cell behaviors. The traction force pointed inward on peripheral FAs in the spread out COT structure. The complex structure in COT provided further investigation of various FA number during different spreading stages. Before the middle phase of spreading (half of maximum spreading area, cell attachment with 8 FAs obtained minimized cytoskeletal energy. The maximum number of 12 FAs in the COT structure was required to achieve further spreading. The stored energy in actin filaments increased as cells spread out, while the energy stored in microtubules increased at initial spreading, peaked in middle phase, and then

  12. Molecular model of the microvillar cytoskeleton and organization of the brush border.

    Directory of Open Access Journals (Sweden)

    Jeffrey W Brown

    Full Text Available BACKGROUND: Brush border microvilli are approximately 1-microm long finger-like projections emanating from the apical surfaces of certain, specialized absorptive epithelial cells. A highly symmetric hexagonal array of thousands of these uniformly sized structures form the brush border, which in addition to aiding in nutrient absorption also defends the large surface area against pathogens. Here, we present a molecular model of the protein cytoskeleton responsible for this dramatic cellular morphology. METHODOLOGY/PRINCIPAL FINDINGS: The model is constructed from published crystallographic and microscopic structures reported by several groups over the last 30+ years. Our efforts resulted in a single, unique, self-consistent arrangement of actin, fimbrin, villin, brush border myosin (Myo1A, calmodulin, and brush border spectrin. The central actin core bundle that supports the microvillus is nearly saturated with fimbrin and villin cross-linkers and has a density similar to that found in protein crystals. The proposed model accounts for all major proteinaceous components, reproduces the experimentally determined stoichiometry, and is consistent with the size and morphology of the biological brush border membrane. CONCLUSIONS/SIGNIFICANCE: The model presented here will serve as a structural framework to explain many of the dynamic cellular processes occurring over several time scales, such as protein diffusion, association, and turnover, lipid raft sorting, membrane deformation, cytoskeletal-membrane interactions, and even effacement of the brush border by invading pathogens. In addition, this model provides a structural basis for evaluating the equilibrium processes that result in the uniform size and structure of the highly dynamic microvilli.

  13. Spaceflight and clinorotation cause cytoskeleton and mitochondria changes and increases in apoptosis in cultured cells

    Science.gov (United States)

    Schatten, H.; Lewis, M. L.; Chakrabarti, A.

    2001-01-01

    The cytoskeleton is a complex network of fibers that is sensitive to environmental factors including microgravity and altered gravitational forces. Cellular functions such as transport of cell organelles depend on cytoskeletal integrity; regulation of cytoskeletal activity plays a role in cell maintenance, cell division, and apoptosis. Here we report cytoskeletal and mitochondria alterations in cultured human lymphocyte (Jurkat) cells after exposure to spaceflight and in insect cells of Drosophila melanogaster (Schneider S-1) after exposure to conditions created by clinostat rotation. Jurkat cells were flown on the space shuttle in Biorack cassettes while Schneider S-1 cells were exposed to altered gravity forces as produced by clinostat rotation. The effects of both treatments were similar in the different cell types. Fifty percent of cells displayed effects on the microtubule network in both cell lines. Under these experimental conditions mitochondria clustering and morphological alterations of mitochondrial cristae was observed to various degrees after 4 and 48 hours of culture. Jurkat cells underwent cell divisions during exposure to spaceflight but a large number of apoptotic cells was also observed. Similar results were obtained in Schneider S-1 cells cultured under clinostat rotation. Both cell lines displayed mitochondria abnormalities and mitochondria clustering toward one side of the cells which is interpreted to be the result of microtubule disruption and failure of mitochondria transport along microtubules. The number of mitochondria was increased in cells exposed to altered gravity while cristae morphology was severely affected indicating altered mitochondria function. These results show that spaceflight as well as altered gravity produced by clinostat rotation affects microtubule and mitochondria organization and results in increases in apoptosis. Grant numbers: NAG 10-0224, NAG2-985. c 2001. Elsevier Science Ltd. All rights reserved.

  14. Intracellular Theileria annulata promote invasive cell motility through kinase regulation of the host actin cytoskeleton.

    Directory of Open Access Journals (Sweden)

    Min Ma

    2014-03-01

    Full Text Available The intracellular, protozoan Theileria species parasites are the only eukaryotes known to transform another eukaryotic cell. One consequence of this parasite-dependent transformation is the acquisition of motile and invasive properties of parasitized cells in vitro and their metastatic dissemination in the animal, which causes East Coast Fever (T. parva or Tropical Theileriosis (T. annulata. These motile and invasive properties of infected host cells are enabled by parasite-dependent, poorly understood F-actin dynamics that control host cell membrane protrusions. Herein, we dissected functional and structural alterations that cause acquired motility and invasiveness of T. annulata-infected cells, to understand the molecular basis driving cell dissemination in Tropical Theileriosis. We found that chronic induction of TNFα by the parasite contributes to motility and invasiveness of parasitized host cells. We show that TNFα does so by specifically targeting expression and function of the host proto-oncogenic ser/thr kinase MAP4K4. Blocking either TNFα secretion or MAP4K4 expression dampens the formation of polar, F-actin-rich invasion structures and impairs cell motility in 3D. We identified the F-actin binding ERM family proteins as MAP4K4 downstream effectors in this process because TNFα-induced ERM activation and cell invasiveness are sensitive to MAP4K4 depletion. MAP4K4 expression in infected cells is induced by TNFα-JNK signalling and maintained by the inhibition of translational repression, whereby both effects are parasite dependent. Thus, parasite-induced TNFα promotes invasive motility of infected cells through the activation of MAP4K4, an evolutionary conserved kinase that controls cytoskeleton dynamics and cell motility. Hence, MAP4K4 couples inflammatory signaling to morphodynamic processes and cell motility, a process exploited by the intracellular Theileria parasite to increase its host cell's dissemination capabilities.

  15. Spaceflight and clinorotation cause cytoskeleton and mitochondria changes and increases in apoptosis in cultured cells

    Science.gov (United States)

    Schatten, Heide; Lewis, Marian L.; Chakrabarti, Amitabha

    2001-08-01

    The cytoskeleton is a complex network of fibers that is sensitive to environmental factors including microgravity and altered gravitational forces. Cellular functions such as transport of cell organelles depend on cytoskeletal integrity; regulation of cytoskeletal activity plays a role in cell maintenance, cell division, and apoptosis. Here we report cytoskeletal and mitochondria alterations in cultured human lymphocyte (Jurkat) cells after exposure to spaceflight and in insect cells of Drosophila melanogaster (Schneider S-1) after exposure to conditions created by clinostat rotation. Jurkat cells were flown on the space shuttle in Biorack cassettes while Schneider S-1 cells were exposed to altered gravity forces as produced by clinostat rotation. The effects of both treatments were similar in the different cell types. Fifty percent of cells displayed effects on the microtubule network in both cell lines. Under these experimental conditions mitochondria clustering and morphological alterations of mitochondrial cristae was observed to various degrees after 4 and 48 hours of culture. Jurkat cells underwent cell divisions during exposure to spaceflight but a large number of apoptotic cells was also observed. Similar results were obtained in Schneider S-1 cells cultured under clinostat rotation. Both cell lines displayed mitochondria abnormalities and mitochondria clustering toward one side of the cells which is interpreted to be the result of microtubule disruption and failure of mitochondria transport along microtubules. The number of mitochondria was increased in cells exposed to altered gravity while cristae morphology was severely affected indicating altered mitochondria function. These results show that spaceflight as well as altered gravity produced by clinostat rotation affects microtubule and mitochondria organization and results in increases in apoptosis.

  16. Hydraulic Pressure during Fluid Flow Regulates Purinergic Signaling and Cytoskeleton Organization of Osteoblasts.

    Science.gov (United States)

    Gardinier, Joseph D; Gangadharan, Vimal; Wang, Liyun; Duncan, Randall L

    2014-06-01

    During physiological activities, osteoblasts experience a variety of mechanical forces that stimulate anabolic responses at the cellular level necessary for the formation of new bone. Previous studies have primarily investigated the osteoblastic response to individual forms of mechanical stimuli. However in this study, we evaluated the response of osteoblasts to two simultaneous, but independently controlled stimuli; fluid flow-induced shear stress (FSS) and static or cyclic hydrostatic pressure (SHP or CHP, respectively). MC3T3-E1 osteoblasts-like cells were subjected to 12dyn/cm(2) FSS along with SHP or CHP of varying magnitudes to determine if pressure enhances the anabolic response of osteoblasts during FSS. For both SHP and CHP, the magnitude of hydraulic pressure that induced the greatest release of ATP during FSS was 15 mmHg. Increasing the hydraulic pressure to 50 mmHg or 100 mmHg during FSS attenuated the ATP release compared to 15 mmHg during FSS. Decreasing the magnitude of pressure during FSS to atmospheric pressure reduced ATP release to that of basal ATP release from static cells and inhibited actin reorganization into stress fibers that normally occurred during FSS with 15 mmHg of pressure. In contrast, translocation of nuclear factor kappa B (NFκB) to the nucleus was independent of the magnitude of hydraulic pressure and was found to be mediated through the activation of phospholipase-C (PLC), but not src kinase. In conclusion, hydraulic pressure during FSS was found to regulate purinergic signaling and actin cytoskeleton reorganization in the osteoblasts in a biphasic manner, while FSS alone appeared to stimulate NFκB translocation. Understanding the effects of hydraulic pressure on the anabolic responses of osteoblasts during FSS may provide much needed insights into the physiologic effects of coupled mechanical stimuli on osteogenesis.

  17. Expression of Rho GTPases family in melanoma cells and its influence on cytoskeleton and migration.

    Science.gov (United States)

    Wen, Si-Jian; Zhang, Wei; Ni, Na-Na; Wu, Qiong; Wang, Xiao-Po; Lin, You-Kun; Sun, Jian-Fang

    2017-05-02

    Rho GTPases family members influenced the filopodia, lamellipodia, stress fiber and adhesion plaque of melanoma cells through regulating cytoskeleton recombination. The role of Rho GTPases family in the migration and invasion of melanoma and its molecular mechanism were explored. The morphological difference between three types of melanoma cells (M14, A375 and MV3) and human melanocyte (MC) was observed by the Hoffman microscope. Cells were stained by phalloidin labeled by rhodamine. The differences between 4 types of cells in filopodia, lamellipodia, stress fiber and adhesion plaque (microfilament is the main constituent) were observed under the super-high resolution microscope. The migration ability of 4 types of cells was detected by Transwell migration assay. QPCR was used to detect the mRNA transcription level of Rho GTPases family. WB was adopted to detect the expression of RhoD and DIAPH2 proteins. There were significant differences in filopodia, lamellipodia, stress fiber and adhesion plaque between MC and 3 types of melanoma cells (M14, A375 and MV3). MC did not have stress fiber or adhesion plaque, while M14, A375 and MV3 had stress fiber and adhesion plaque. All 4 types of cells had thin and short filopodia. MV3 had fewer but thicker stress fibers than the latter two. Transwell migration test indicated the followings: M14 and A375 had a similar high migration rate; the migration rate of MV3 was slightly low; MC did not have the ability of transmembrane migration. QPCR results of Rho GTPases family in 4 types of cells showed the change corresponding to immunofluorescence. WB results showed that RhoD was barely expressed in M14, A375 or MV3. DIAPH2, the downstream effector molecule of RhoD, had the corresponding change. Rho GTPases influences the migration and invasion of melanoma cells through regulating filopodia, lamellipodia, stress fiber and adhesion plaque (microfilament is the main constituent).

  18. Caspase-2 short isoform interacts with membrane-associated cytoskeleton proteins to inhibit apoptosis.

    Directory of Open Access Journals (Sweden)

    Chunhua Han

    Full Text Available Caspase-2 (casp-2 is the most conserved caspase across species, and is one of the initiator caspases activated by various stimuli. The casp-2 gene produces several alternative splicing isoforms. It is believed that the long isoform, casp-2L, promotes apoptosis, whereas the short isoform, casp-2S, inhibits apoptosis. The actual effect of casp-2S on apoptosis is still controversial, however, and the underlying mechanism for casp-2S-mediated apoptosis inhibition is unclear. Here, we analyzed the effects of casp-2S on DNA damage induced apoptosis through "gain-of-function" and "loss-of-function" strategies in ovarian cancer cell lines. We clearly demonstrated that the over-expression of casp-2S inhibited, and the knockdown of casp-2S promoted, the cisplatin-induced apoptosis of ovarian cancer cells. To explore the mechanism by which casp-2S mediates apoptosis inhibition, we analyzed the proteins which interact with casp-2S in cells by using immunoprecipitation (IP and mass spectrometry. We have identified two cytoskeleton proteins, Fodrin and α-Actinin 4, which interact with FLAG-tagged casp-2S in HeLa cells and confirmed this interaction through reciprocal IP. We further demonstrated that casp-2S (i is responsible for inhibiting DNA damage-induced cytoplasmic Fodrin cleavage independent of cellular p53 status, and (ii prevents cisplatin-induced membrane blebbing. Taken together, our data suggests that casp-2S affects cellular apoptosis through its interaction with membrane-associated cytoskeletal Fodrin protein.

  19. Imetelstat (a telomerase antagonist) exerts off‑target effects on the cytoskeleton.

    Science.gov (United States)

    Mender, Ilgen; Senturk, Serif; Ozgunes, Nuriman; Akcali, K Can; Kletsas, Dimitris; Gryaznov, Sergei; Can, Alp; Shay, Jerry W; Dikmen, Z Gunnur

    2013-05-01

    Telomerase is a cellular ribonucleoprotein reverse transcriptase that plays a crucial role in telomere maintenance. This enzyme is expressed in approximately 90% of human tumors, but not in the majority of normal somatic cells. imetelstat sodium (GRN163L), is a 13-mer oligonucleotide N3'→P5' thio-phosphoramidate lipid conjugate, which represents the latest generation of telomerase inhibitors targeting the template region of the human functional telomerase RNA (hTR) subunit. In preclinical trials, this compound has been found to inhibit telomerase activity in multiple cancer cell lines, as well as in vivo xenograft mouse models. Currently, GRN163L is being investigated in several clinical trials, including a phase II human non‑small cell lung cancer clinical trial, in a maintenance setting following standard doublet chemotherapy. In addition to the inhibition of telomerase activity in cancer cell lines, GRN163L causes morphological cell rounding changes, independent of hTR expression or telomere length. This leads to the loss of cell adhesion properties; however, the mechanism underlying this effect is not yet fully understood. In the present study, we observed that GRN163L treatment leads to the loss of adhesion in A549 lung cancer cells, due to decreased E-cadherin expression, leading to the disruption of the cytoskeleton through the alteration of actin, tubulin and intermediate filament organization. Consequently, the less adherent cancer cells initially cease to proliferate and are arrested in the G1 phase of the cell cycle, accompanied by decreased matrix metalloproteinase-2 (MMP-2) expression. These effects of GRN163L are independent of its telomerase catalytic activity and may increase the therapeutic efficacy of GRN163L by decreasing the adhesion, proliferation and metastatic potential of cancer cells in vivo.

  20. The Interference of Selected Cytotoxic Alkaloids with the Cytoskeleton: An Insight into Their Modes of Action

    Directory of Open Access Journals (Sweden)

    Xiaojuan Wang

    2016-07-01

    Full Text Available Alkaloids, the largest group among the nitrogen-containing secondary metabolites of plants, usually interact with several molecular targets. In this study, we provide evidence that six cytotoxic alkaloids (sanguinarine, chelerythrine, chelidonine, noscapine, protopine, homoharringtonine, which are known to affect neuroreceptors, protein biosynthesis and nucleic acids, also interact with the cellular cytoskeleton, such as microtubules and actin filaments, as well. Sanguinarine, chelerythrine and chelidonine depolymerized the microtubule network in living cancer cells (Hela cells and human osteosarcoma U2OS cells and inhibited tubulin polymerization in vitro with IC50 values of 48.41 ± 3.73, 206.39 ± 4.20 and 34.51 ± 9.47 μM, respectively. However, sanguinarine and chelerythrine did not arrest the cell cycle while 2.5 μM chelidonine arrested the cell cycle in the G2/M phase with 88.27% ± 0.99% of the cells in this phase. Noscapine and protopine apparently affected microtubule structures in living cells without affecting tubulin polymerization in vitro, which led to cell cycle arrest in the G2/M phase, promoting this cell population to 73.42% ± 8.31% and 54.35% ± 11.26% at a concentration of 80 μM and 250.9 μM, respectively. Homoharringtonine did not show any effects on microtubules and cell cycle, while the known microtubule-stabilizing agent paclitaxel was found to inhibit tubulin polymerization in the presence of MAPs in vitro with an IC50 value of 38.19 ± 3.33 μM. Concerning actin filaments, sanguinarine, chelerythrine and chelidonine exhibited a certain effect on the cellular actin filament network by reducing the mass of actin filaments. The interactions of these cytotoxic alkaloids with microtubules and actin filaments present new insights into their molecular modes of action.

  1. A general framework for optimization of probes for gene expression microarray and its application to the fungus Podospora anserina

    Directory of Open Access Journals (Sweden)

    Bidard Frédérique

    2010-06-01

    Full Text Available Abstract Background The development of new microarray technologies makes custom long oligonucleotide arrays affordable for many experimental applications, notably gene expression analyses. Reliable results depend on probe design quality and selection. Probe design strategy should cope with the limited accuracy of de novo gene prediction programs, and annotation up-dating. We present a novel in silico procedure which addresses these issues and includes experimental screening, as an empirical approach is the best strategy to identify optimal probes in the in silico outcome. Findings We used four criteria for in silico probe selection: cross-hybridization, hairpin stability, probe location relative to coding sequence end and intron position. This latter criterion is critical when exon-intron gene structure predictions for intron-rich genes are inaccurate. For each coding sequence (CDS, we selected a sub-set of four probes. These probes were included in a test microarray, which was used to evaluate the hybridization behavior of each probe. The best probe for each CDS was selected according to three experimental criteria: signal-to-noise ratio, signal reproducibility, and representative signal intensities. This procedure was applied for the development of a gene expression Agilent platform for the filamentous fungus Podospora anserina and the selection of a single 60-mer probe for each of the 10,556 P. anserina CDS. Conclusions A reliable gene expression microarray version based on the Agilent 44K platform was developed with four spot replicates of each probe to increase statistical significance of analysis.

  2. AnyExpress: Integrated toolkit for analysis of cross-platform gene expression data using a fast interval matching algorithm

    Directory of Open Access Journals (Sweden)

    Jung Hyunchul

    2011-03-01

    Full Text Available Abstract Background Cross-platform analysis of gene express data requires multiple, intricate processes at different layers with various platforms. However, existing tools handle only a single platform and are not flexible enough to support custom changes, which arise from the new statistical methods, updated versions of reference data, and better platforms released every month or year. Current tools are so tightly coupled with reference information, such as reference genome, transcriptome database, and SNP, which are often erroneous or outdated, that the output results are incorrect and misleading. Results We developed AnyExpress, a software package that combines cross-platform gene expression data using a fast interval-matching algorithm. Supported platforms include next-generation-sequencing technology, microarray, SAGE, MPSS, and more. Users can define custom target transcriptome database references for probe/read mapping in any species, as well as criteria to remove undesirable probes/reads. AnyExpress offers scalable processing features such as binding, normalization, and summarization that are not present in existing software tools. As a case study, we applied AnyExpress to published Affymetrix microarray and Illumina NGS RNA-Seq data from human kidney and liver. The mean of within-platform correlation coefficient was 0.98 for within-platform samples in kidney and liver, respectively. The mean of cross-platform correlation coefficients was 0.73. These results confirmed those of the original and secondary studies. Applying filtering produced higher agreement between microarray and NGS, according to an agreement index calculated from differentially expressed genes. Conclusion AnyExpress can combine cross-platform gene expression data, process data from both open- and closed-platforms, select a custom target reference, filter out undesirable probes or reads based on custom-defined biological features, and perform quantile-normalization with

  3. Calibration Fixture For Anemometer Probes

    Science.gov (United States)

    Lewis, Charles R.; Nagel, Robert T.

    1993-01-01

    Fixture facilitates calibration of three-dimensional sideflow thermal anemometer probes. With fixture, probe oriented at number of angles throughout its design range. Readings calibrated as function of orientation in airflow. Calibration repeatable and verifiable.

  4. NASA's geostationary communications platform program

    Science.gov (United States)

    Ramler, J.; Durrett, R.

    1984-01-01

    This paper reviews recent trends in communications satellites and explains NASA's current interest in geostationary communications platforms. Large communications platforms capable of supporting multiple payloads with common utilities have been examined in a number of studies since 1974 and appear to offer a number of potential advantages. In 1981, an Industry Briefing and Workshop sponsord by NASA focused on the institutional, operational and technical issues that will influence the implementation of geostationary platforms. The workshop identified numerous issues and problem areas that needed more detailed study. To address the issues/problems identified, a NASA geostationary communications platform program has been developed. This program is described, focusing on the initial studies to be performed.

  5. Platform attitude data acquisition system

    Digital Repository Service at National Institute of Oceanography (India)

    Afzulpurkar, S.

    A system for automatic acquisition of underwater platform attitude data has been designed, developed and tested in the laboratory. This is a micro controller based system interfacing dual axis inclinometer, high-resolution digital compass...

  6. Elevated Fixed Platform Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Elevated Fixed Platform (EFP) is a helicopter recovery test facility located at Lakehurst, NJ. It consists of a 60 by 85 foot steel and concrete deck built atop...

  7. Platforms for Innovation and Internationalization

    DEFF Research Database (Denmark)

    Rasmussen, Erik Stavnsager; Petersen, Nicolaj Hannesbo

    2017-01-01

    The high-tech global startup has many challenges related to both innovation and internationalization. From a Danish cluster of Welfare Tech firms, eight innovative and international firms were selected and interviewed. Such firms typically have to be agile and operate in virtual networks in almost...... all parts of their value chains. This article contributes to the understanding of how innovation and internationalization to a great extent are interlinked. The firms have developed a core product or service offering, which the firms often describe as “a platform”. Around the platform, they develop...... their products and services for new customers and users in new countries. The firms have to sustain a strong focus on the platform while at the same time developing their platform solution for new products, new customers, and new markets. This pivoting makes it possible to use the platform in a new context...

  8. Disentangling Competition Among Platform Driven Strategic Groups

    DEFF Research Database (Denmark)

    Kazan, Erol; Tan, Chee-Wee; Lim, Eric

    2015-01-01

    In platform-driven markets, competitive advantage is derived from superior platform design and configurations. For this reason, platform owners strive to create unique and inimitable platform configurals to maintain and extend their competitiveness within network economies. To disentangle firm...... competition within platform-driven markets, we opted for the UK mobile payment market as our empirical setting. By embracing the theoretical lens of strategic groups and digital platforms, this study supplements prior research by deriving a taxonomy of platform-driven strategic groups that is grounded...... on competitive attributes of platform- driven markets; namely interfirm modularity and strategic linkages....

  9. Disentangling Competition Among Platform Driven Strategic Groups

    DEFF Research Database (Denmark)

    Kazan, Erol; Tan, Chee-Wee; Lim, Eric

    2015-01-01

    competition within platform-driven markets, we opted for the UK mobile payment market as our empirical setting. By embracing the theoretical lens of strategic groups and digital platforms, this study supplements prior research by deriving a taxonomy of platform-driven strategic groups that is grounded......In platform-driven markets, competitive advantage is derived from superior platform design and configurations. For this reason, platform owners strive to create unique and inimitable platform configurals to maintain and extend their competitiveness within network economies. To disentangle firm...... on competitive attributes of platform- driven markets; namely interfirm modularity and strategic linkages....

  10. Pico Reentry Probes: Affordable Options for Reentry Measurements and Testing

    Science.gov (United States)

    Ailor, William H.; Kapoor, Vinod B.; Allen, Gay A., Jr.; Venkatapathy, Ethiraj; Arnold, James O.; Rasky, Daniel J.

    2005-01-01

    It is generally very costly to perform in-space and atmospheric entry experiments. This paper presents a new platform - the Pico Reentry Probe (PREP) - that we believe will make targeted flight-tests and planetary atmospheric probe science missions considerably more affordable. Small, lightweight, self-contained, it is designed as a "launch and forget" system, suitable for experiments that require no ongoing communication with the ground. It contains a data recorder, battery, transmitter, and user-customized instrumentation. Data recorded during reentry or space operations is returned at end-of-mission via transmission to Iridium satellites (in the case of earth-based operations) or a similar orbiting communication system for planetary missions. This paper discusses possible applications of this concept for Earth and Martian atmospheric entry science. Two well-known heritage aerodynamic shapes are considered as candidates for PREP: the shape developed for the Planetary Atmospheric Experiment Test (PAET) and that for the Deep Space II Mars Probe.

  11. Probing properties of cold radiofrequency plasma with polymer probe

    Science.gov (United States)

    Bormashenko, E.; Chaniel, G.; Multanen, V.

    2015-01-01

    The probe intended for the characterization of cold plasma is introduced. The probe allows the estimation of Debye length of cold plasma. The probe is based on the pronounced modification of surface properties (wettability) of polymer films by cold plasmas. The probe was tested with the cold radiofrequency inductive air plasma discharge. The Debye length and the concentration of charge carriers were estimated for various gas pressures. The reported results coincide reasonably with the corresponding values established by other methods. The probe makes possible measurement of characteristics of cold plasmas in closed chambers.

  12. Probing Properties of Cold Radiofrequency Plasma with Polymer Probe

    CERN Document Server

    Bormashenko, Edward; Multanen, Victor

    2014-01-01

    The probe intended for the characterization of cold plasma is introduced. The probe allows estimation of the Debye length of the cold plasma. The probe is based on the pronounced modification of surface properties (wettability) of polymer films by cold plasmas. The probe was tested with the cold radiofrequency inductive air plasma discharge. The Debye length and the concentration of charge carriers were estimated for various gas pressures. The reported results coincide reasonably with the corresponding values established by other methods. The probe makes possible measurement of characteristics of cold plasmas in closed chambers.

  13. Phoenix Conductivity Probe

    Science.gov (United States)

    2008-01-01

    This image taken by the Surface Stereo Imager on Sol 49, or the 49th Martian day of the mission (July 14, 2008), shows thermal and electrical conductivity probe on NASA's Phoenix Mars Lander's Robotic Arm. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is led by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  14. Atom probe tomography today

    OpenAIRE

    Alfred Cerezo; Peter H. Clifton; Mark J. Galtrey; Humphreys, Colin J.; Kelly, Thomas. F.; David J. Larson; Sergio Lozano-Perez; Marquis, Emmanuelle A.; Oliver, Rachel A.; Gang Sha; Keith Thompson; Mathijs Zandbergen; Roger L. Alvis

    2007-01-01

    This review aims to describe and illustrate the advances in the application of atom probe tomography that have been made possible by recent developments, particularly in specimen preparation techniques (using dual-beam focused-ion beam instruments) but also of the more routine use of laser pulsing. The combination of these two developments now permits atomic-scale investigation of site-specific regions within engineering alloys (e.g. at grain boundaries and in the vicinity of cracks) and also...

  15. Einstein Inflationary Probe (EIP)

    Science.gov (United States)

    Hinshaw, Gary

    2004-01-01

    I will discuss plans to develop a concept for the Einstein Inflation Probe: a mission to detect gravity waves from inflation via the unique signature they impart to the cosmic microwave background (CMB) polarization. A sensitive CMB polarization satellite may be the only way to probe physics at the grand-unified theory (GUT) scale, exceeding by 12 orders of magnitude the energies studied at the Large Hadron Collider. A detection of gravity waves would represent a remarkable confirmation of the inflationary paradigm and set the energy scale at which inflation occurred when the universe was a fraction of a second old. Even a strong upper limit to the gravity wave amplitude would be significant, ruling out many common models of inflation, and pointing to inflation occurring at much lower energy, if at all. Measuring gravity waves via the CMB polarization will be challenging. We will undertake a comprehensive study to identify the critical scientific requirements for the mission and their derived instrumental performance requirements. At the core of the study will be an assessment of what is scientifically and experimentally optimal within the scope and purpose of the Einstein Inflation Probe.

  16. Nanoscale thermal probing

    Directory of Open Access Journals (Sweden)

    Yanan Yue

    2012-03-01

    Full Text Available Nanoscale novel devices have raised the demand for nanoscale thermal characterization that is critical for evaluating the device performance and durability. Achieving nanoscale spatial resolution and high accuracy in temperature measurement is very challenging due to the limitation of measurement pathways. In this review, we discuss four methodologies currently developed in nanoscale surface imaging and temperature measurement. To overcome the restriction of the conventional methods, the scanning thermal microscopy technique is widely used. From the perspective of measuring target, the optical feature size method can be applied by using either Raman or fluorescence thermometry. The near-field optical method that measures nanoscale temperature by focusing the optical field to a nano-sized region provides a non-contact and non-destructive way for nanoscale thermal probing. Although the resistance thermometry based on nano-sized thermal sensors is possible for nanoscale thermal probing, significant effort is still needed to reduce the size of the current sensors by using advanced fabrication techniques. At the same time, the development of nanoscale imaging techniques, such as fluorescence imaging, provides a great potential solution to resolve the nanoscale thermal probing problem.

  17. A comparison of alternative 60-mer probe designs in an in-situ synthesized oligonucleotide microarray

    Directory of Open Access Journals (Sweden)

    Fairbanks Benjamin D

    2006-04-01

    Full Text Available Abstract Background DNA microarrays have proven powerful for functional genomics studies. Several technologies exist for the generation of whole-genome arrays. It is well documented that 25mer probes directed against different regions of the same gene produce variable signal intensity values. However, the extent to which this is true for probes of greater length (60mers is not well characterized. Moreover, this information has not previously been reported for whole-genome arrays designed against bacteria, whose genomes may differ substantially in characteristics directly affecting microarray performance. Results We report here an analysis of alternative 60mer probe designs for an in-situ synthesized oligonucleotide array for the GC rich, β-proteobacterium Burkholderia cenocepacia. Probes were designed using the ArrayOligoSel3.5 software package and whole-genome microarrays synthesized by Agilent, Inc. using their in-situ, ink-jet technology platform. We first validated the quality of the microarrays as demonstrated by an average signal to noise ratio of >1000. Next, we determined that the variance of replicate probes (1178 total probes examined of identical sequence was 3.8% whereas the variance of alternative probes (558 total alternative probes examined designs was 9.5%. We determined that depending upon the definition, about 2.4% of replicate and 7.8% of alternative probes produced outlier conclusions. Finally, we determined none of the probe design subscores (GC content, internal repeat, binding energy and self annealment produced by ArrayOligoSel3.5 were predictive or probes that produced outlier signals. Conclusion Our analysis demonstrated that the use of multiple probes per target sequence is not essential for in-situ synthesized 60mer oligonucleotide arrays designed against bacteria. Although probes producing outlier signals were identified, the use of ratios results in less than 10% of such outlier conclusions. We also determined that

  18. A Typology of Multi-sided Platforms

    DEFF Research Database (Denmark)

    Staykova, Kalina Stefanova; Damsgaard, Jan

    2015-01-01

    exemplary cases which allow us to illustrate the platform heterogeneity and to support new MSPs typology. As examples we include a physical two-sided platform (Gatwick Airport) that adds a third side, a digital one-sided platform transformed into being two-sided (Pingit) and a digital one-sided platform......In this paper we address how the composition of a platform impacts the platform’s business model. By platform’s business model we mean platform features, platform architecture and platform governance. To this end, we construct the Platform Business Model Framework. We apply the framework to three...... in several configurations. The particular platform architecture can explain the difficulties in designing a viable business models for platforms....

  19. Nine New Fluorescent Probes

    Science.gov (United States)

    Lin, Tsung-I.; Jovanovic, Misa V.; Dowben, Robert M.

    1989-06-01

    Absorption and fluorescence spectroscopic studies are reported here for nine new fluorescent probes recently synthesized in our laboratories: four pyrene derivatives with substituents of (i) 1,3-diacetoxy-6,8-dichlorosulfonyl, (ii) 1,3-dihydroxy-6,8-disodiumsulfonate, (iii) 1,3-disodiumsulfonate, and (iv) l-ethoxy-3,6,8-trisodiumsulfonate groups, and five [7-julolidino] coumarin derivatives with substituents of (v) 3-carboxylate-4-methyl, (vi) 3- methylcarboxylate, (vii) 3-acetate-4-methyl, (viii) 3-propionate-4-methyl, and (ix) 3-sulfonate-4-methyl groups. Pyrene compounds i and ii and coumarin compounds v and vi exhibit interesting absorbance and fluorescence properties: their absorption maxima are red shifted compared to the parent compound to the blue-green region, and the band width broadens considerably. All four blue-absorbing dyes fluoresce intensely in the green region, and the two pyrene compounds emit at such long wavelengths without formation of excimers. The fluorescence properties of these compounds are quite environment-sensitive: considerable spectral shifts and fluorescence intensity changes have been observed in the pH range from 3 to 10 and in a wide variety of polar and hydrophobic solvents with vastly different dielectric constants. The high extinction and fluorescence quantum yield of these probes make them ideal fluorescent labeling reagents for proteins, antibodies, nucleic acids, and cellular organelles. The pH and hydrophobicity-dependent fluorescence changes can be utilized as optical pH and/or hydrophobicity indicators for mapping environmental difference in various cellular components in a single cell. Since all nine probes absorb in the UV, but emit at different wavelengths in the visible, these two groups of compounds offer an advantage of utilizing a single monochromatic light source (e.g., a nitrogen laser) to achieve multi-wavelength detection for flow cytometry application. As a first step to explore potential application in

  20. A complete manipulation platform for characterization of micro-components

    Science.gov (United States)

    Canales, C.; Cosandier, F.; Boetsch, G.; Chatagny, V.; Lee, J. H.; Bringout, G.; Clavel, R.

    2008-11-01

    This paper presents a complete manipulation platform for characterization of micro-components that is being developed in the scope of the European project GOLEM. Various tools such as electrical probes and force sensors have been designed and integrated on both high precision mobile micro-robots and fixed manipulators in order to interact with micro-objects. The platform enables the user to characterize parts with sizes ranging from sub-micrometer up to the millimeter. Forces ranging from 1 mN up to 120 mN can be measured as well as electrical resistivity of microcomponents. As the characterization platform is aimed to be used by material scientists and biologists, the manipulation is "assisted" so that the user focuses on the application and not on the robotic systems. One of the key features is that the control software will automatically bring the end-effectors of the manipulators in the local (microscope) field of view. The platform is composed of an XY stage mounted on an inverted optical microscope, of manipulators (fixed and mobile) and of various sensors (optical, force and electrical).

  1. A Portable and Autonomous Magnetic Detection Platform for Biosensing

    Directory of Open Access Journals (Sweden)

    Moisés S. Piedade

    2009-05-01

    Full Text Available This paper presents a prototype of a platform for biomolecular recognition detection. The system is based on a magnetoresistive biochip that performs biorecognition assays by detecting magnetically tagged targets. All the electronic circuitry for addressing, driving and reading out signals from spin-valve or magnetic tunnel junctions sensors is implemented using off-the-shelf components. Taking advantage of digital signal processing techniques, the acquired signals are processed in real time and transmitted to a digital analyzer that enables the user to control and follow the experiment through a graphical user interface. The developed platform is portable and capable of operating autonomously for nearly eight hours. Experimental results show that the noise level of the described platform is one order of magnitude lower than the one presented by the previously used measurement set-up. Experimental results also show that this device is able to detect magnetic nanoparticles with a diameter of 250 nm at a concentration of about 40 fM. Finally, the biomolecular recognition detection capabilities of the platform are demonstrated by performing a hybridization assay using complementary and non-complementary probes and a magnetically tagged 20mer single stranded DNA target.

  2. Porous silicon optical cavity as an immunosensor platform

    Science.gov (United States)

    Lv, Xiao-Yi; Mo, Jia-Qing; Tu, Yi-Xian; Zhong, Fu-Ru; Jiang, Tao; Jia, Zhen-Hong; Li, Jiang-Wei; Zhang, Fu-Chun

    2010-07-01

    A novel porous silicon based optical Fabry-Perot cavity structure is prepared as a label-free immunosensor platform for detecting antigen-antibody. The lagurus zona pelluciad 3 (LZP3) and the specificity of the polyclonal anti-LZP3 antibodies are employed in our laboratory as the target and the probe, respectively. Firstly, the antibodies are immobilized to the porous silicon optical cavity using silanization and glutaraldehyde (GA) chemistry. And then, after the antigen-antibody reaction, it is monitored that the red shift of the reflection spectrum of the immunosensor increases with the antigen concentration. This research also plays a potential role for the extensive applications in immunoassay.

  3. Role of G protein signaling in the formation of the fibrin(ogen)-integrin αIIbβ3-actin cytoskeleton complex in platelets.

    Science.gov (United States)

    Budnik, Ivan; Shenkman, Boris; Savion, Naphtali

    2016-09-01

    Effective platelet function requires formation of a physical link between fibrin(ogen), integrin αIIbβ3, and cytoplasmic actin filaments. We investigated the role of the Gαq, Gαi, and Gα12/13 families of heterotrimeric GTP-binding proteins (G proteins) in the assembly of a ligand-αIIbβ3-actin cytoskeleton complex. Selective and combined activation of the G proteins was achieved by using combinations of various platelet agonists and inhibitors. Formation and stability of fibrinogen-αIIbβ3 interaction were evaluated by the extent of platelet aggregation and the rate of eptifibatide-induced platelet disaggregation; association of αIIbβ3 with the cytoskeleton was analyzed by western blot. Formation of the fibrin-αIIbβ3-actin cytoskeleton complex was evaluated by rotational thromboelastometry assay in which clot formation was induced by the mixture of reptilase and factor XIIIa. We demonstrated that involvement of heterotrimeric G proteins in the formation of the ligand-αIIbβ3-cytoskeleton complex depends on whether fibrinogen or fibrin serves as the integrin ligand. Formation of the fibrinogen-αIIbβ3-cytoskeleton complex requires combined activation of at least two G protein pathways while the maximal αIIbβ3-cytoskeleton association and the strongest αIIbβ3-fibrinogen binding supporting irreversible platelet aggregation require combined activation of all three-Gαq, Gαi, and Gα12/13-G protein families. In contrast, formation of the fibrin-αIIbβ3-cytoskeleton complex mediating clot retraction is critically dependent on the activation of the Gαi family, especially on the activation of Gαz.

  4. Highly sensitive and multiplexed platforms for allergy diagnostics

    Science.gov (United States)

    Monroe, Margo R.

    Allergy is a disorder of the immune system caused by an immune response to otherwise harmless environmental allergens. Currently 20% of the US population is allergic and 90% of pediatric patients and 60% of adult patients with asthma have allergies. These percentages have increased by 18.5% in the past decade, with predicted similar trends for the future. Here we design sensitive, multiplexed platforms to detect allergen-specific IgE using the Interferometric Reflectance Imaging Sensor (IRIS) for various clinical settings. A microarray platform for allergy diagnosis allows for testing of specific IgE sensitivity to a multitude of allergens, while requiring only small volumes of patient blood sample. However, conventional fluorescent microarray technology is limited by i) the variation of probe immobilization, which hinders the ability to make quantitative, assertive, and statistically relevant conclusions necessary in immunodiagnostics and ii) the use of fluorophore labels, which is not suitable for some clinical applications due to the tendency of fluorophores to stick to blood particulates and require daily calibration methods. This calibrated fluorescence enhancement (CaFE) method integrates the low magnification modality of IRIS with enhanced fluorescence sensing in order to directly correlate immobilized probe (major allergens) density to allergen-specific IgE in patient serum. However, this platform only operates in processed serum samples, which is not ideal for point of care testing. Thus, a high magnification modality of IRIS was adapted as an alternative allergy diagnostic platform to automatically discriminate and size single nanoparticles bound to specific IgE in unprocessed, characterized human blood and serum samples. These features make IRIS an ideal candidate for clinical and diagnostic applications, such a POC testing. The high magnification (nanoparticle counting) modality in conjunction with low magnification of IRIS in a combined instrument

  5. Development of Mackintosh Probe Extractor

    Science.gov (United States)

    Rahman, Noor Khazanah A.; Kaamin, Masiri; Suwandi, Amir Khan; Sahat, Suhaila; Jahaya Kesot, Mohd

    2016-11-01

    Dynamic probing is a continuous soil investigation technique, which is one of the simplest soil penetration test. It basically consist of repeatedly driving a metal tipped probe into the ground using a drop weight of fixed mass and travel. Testing was carried out continuously from ground level to the final penetration depth. Once the soil investigation work done, it is difficult to pull out the probe rod from the ground, due to strong soil structure grip against probe cone and prevent the probe rod out from the ground. Thus, in this case, a tool named Extracting Probe was created to assist in the process of retracting the probe rod from the ground. In addition, Extracting Probe also can reduce the time to extract the probe rod from the ground compare with the conventional method. At the same time, it also can reduce manpower cost because only one worker involve to handle this tool compare with conventional method used two or more workers. From experiment that have been done we found that the time difference between conventional tools and extracting probe is significant, average time difference is 155 minutes. In addition the extracting probe can reduce manpower usage, and also labour cost for operating the tool. With all these advantages makes this tool has the potential to be marketed.

  6. Probe-based data storage

    CERN Document Server

    Koelmans, Wabe W; Abelmann, L

    2015-01-01

    Probe-based data storage attracted many researchers from academia and industry, resulting in unprecendeted high data-density demonstrations. This topical review gives a comprehensive overview of the main contributions that led to the major accomplishments in probe-based data storage. The most investigated technologies are reviewed: topographic, phase-change, magnetic, ferroelectric and atomic and molecular storage. Also, the positioning of probes and recording media, the cantilever arrays and parallel readout of the arrays of cantilevers are discussed. This overview serves two purposes. First, it provides an overview for new researchers entering the field of probe storage, as probe storage seems to be the only way to achieve data storage at atomic densities. Secondly, there is an enormous wealth of invaluable findings that can also be applied to many other fields of nanoscale research such as probe-based nanolithography, 3D nanopatterning, solid-state memory technologies and ultrafast probe microscopy.

  7. F-actin cytoskeleton and the fate of organelles in chromaffin cells.

    Science.gov (United States)

    Villanueva, José; Gimenez-Molina, Yolanda; Viniegra, Salvador; Gutiérrez, Luis M

    2016-06-01

    In addition to playing a fundamental structural role, the F-actin cytoskeleton in neuroendocrine chromaffin cells has a prominent influence on governing the molecular mechanism and regulating the secretory process. Performing such roles, the F-actin network might be essential to first transport, and later locate the cellular organelles participating in the secretory cycle. Chromaffin granules are transported from the internal cytosolic regions to the cell periphery along microtubular and F-actin structures. Once in the cortical region, they are embedded in the F-actin network where these vesicles experience restrictions in motility. Similarly, mitochondria transport is affected by both microtubule and F-actin inhibitors and suffers increasing motion restrictions when they are located in the cortical region. Therefore, the F-actin cortex is a key factor in defining the existence of two populations of cortical and perinuclear granules and mitochondria which could be distinguished by their different location and mobility. Interestingly, other important organelles for controlling intracellular calcium levels, such as the endoplasmic reticulum network, present clear differences in distribution and much lower mobility than chromaffin vesicles and mitochondria. Nevertheless, both mitochondria and the endoplasmic reticulum appear to distribute in the proximity of secretory sites to fulfill a pivotal role, forming triads with calcium channels ensuring the fine tuning of the secretory response. This review presents the contributions that provide the basis for our current view regarding the influence that F-actin has on the distribution of organelles participating in the release of catecholamines in chromaffin cells, and summarizes this knowledge in simple models. In chromaffin cells, organelles such as granules and mitochondria distribute forming cortical and perinuclear populations whereas others like the ER present homogenous distributions. In the present review we discuss

  8. Systematic evaluation of three microRNA profiling platforms: microarray, beads array, and quantitative real-time PCR array.

    Science.gov (United States)

    Wang, Bin; Howel, Paul; Bruheim, Skjalg; Ju, Jingfang; Owen, Laurie B; Fodstad, Oystein; Xi, Yaguang

    2011-02-11

    A number of gene-profiling methodologies have been applied to microRNA research. The diversity of the platforms and analytical methods makes the comparison and integration of cross-platform microRNA profiling data challenging. In this study, we systematically analyze three representative microRNA profiling platforms: Locked Nucleic Acid (LNA) microarray, beads array, and TaqMan quantitative real-time PCR Low Density Array (TLDA). The microRNA profiles of 40 human osteosarcoma xenograft samples were generated by LNA array, beads array, and TLDA. Results show that each of the three platforms perform similarly regarding intra-platform reproducibility or reproducibility of data within one platform while LNA array and TLDA had the best inter-platform reproducibility or reproducibility of data across platforms. The endogenous controls/probes contained in each platform have been observed for their stability under different treatments/environments; those included in TLDA have the best performance with minimal coefficients of variation. Importantly, we identify that the proper selection of normalization methods is critical for improving the inter-platform reproducibility, which is evidenced by the application of two non-linear normalization methods (loess and quantile) that substantially elevated the sensitivity and specificity of the statistical data assessment. Each platform is relatively stable in terms of its own microRNA profiling intra-reproducibility; however, the inter-platform reproducibility among different platforms is low. More microRNA specific normalization methods are in demand for cross-platform microRNA microarray data integration and comparison, which will improve the reproducibility and consistency between platforms.

  9. Transcriptome sequencing and genome-wide association analyses reveal lysosomal function and actin cytoskeleton remodeling in schizophrenia and bipolar disorder.

    Science.gov (United States)

    Zhao, Z; Xu, J; Chen, J; Kim, S; Reimers, M; Bacanu, S-A; Yu, H; Liu, C; Sun, J; Wang, Q; Jia, P; Xu, F; Zhang, Y; Kendler, K S; Peng, Z; Chen, X

    2015-05-01

    Schizophrenia (SCZ) and bipolar disorder (BPD) are severe mental disorders with high heritability. Clinicians have long noticed the similarities of clinic symptoms between these disorders. In recent years, accumulating evidence indicates some shared genetic liabilities. However, what is shared remains elusive. In this study, we conducted whole transcriptome analysis of post-mortem brain tissues (cingulate cortex) from SCZ, BPD and control subjects, and identified differentially expressed genes in these disorders. We found 105 and 153 genes differentially expressed in SCZ and BPD, respectively. By comparing the t-test scores, we found that many of the genes differentially expressed in SCZ and BPD are concordant in their expression level (q⩽0.01, 53 genes; q⩽0.05, 213 genes; q⩽0.1, 885 genes). Using genome-wide association data from the Psychiatric Genomics Consortium, we found that these differentially and concordantly expressed genes were enriched in association signals for both SCZ (Pgenes show concordant expression and association for both SCZ and BPD. Pathway analyses of these genes indicated that they are involved in the lysosome, Fc gamma receptor-mediated phagocytosis, regulation of actin cytoskeleton pathways, along with several cancer pathways. Functional analyses of these genes revealed an interconnected pathway network centered on lysosomal function and the regulation of actin cytoskeleton. These pathways and their interacting network were principally confirmed by an independent transcriptome sequencing data set of the hippocampus. Dysregulation of lysosomal function and cytoskeleton remodeling has direct impacts on endocytosis, phagocytosis, exocytosis, vesicle trafficking, neuronal maturation and migration, neurite outgrowth and synaptic density and plasticity, and different aspects of these processes have been implicated in SCZ and BPD.

  10. Downregulation of tumorogenicity and changes in the actin cytoskeleton of murine hepatoma after irradiation with polychromatic visible and IR light.

    Science.gov (United States)

    Knyazev, Nickolay A; Samoilova, Kira A; Abrahamse, Heidi; Filatova, Natalia A

    2015-04-01

    This study evaluated the function and structural consequences of direct exposure of murine hepatoma MH-22a cells to polychromatic polarized light, to determine potential risk of malignancy following irradiation. Visible (VIS) and infrared (IR) light have been actively used for prevention and treatment of complications developed after conventional tumor therapy. However, the safety associated with this irradiation has not been determined. Polychromatic light (480-3400 and 385-750 nm), were used at different doses (4.8-38.4 J/cm(2)) to determine the viability, proliferation, and actin cytoskeleton in vitro by flow cytometry and confocal microscopy. Tumorogenic properties of cells were studied in vivo after transplantation in C3HA mice. Polychromatic light of a wide range of doses did not change the viability and proliferation of cells. After transplantation of cells irradiated with VIS-IR light (4.8 and 9.6 J/cm(2)) and VIS light (38.4 J/cm(2)) the tumor volume was lower in the treated group than in the control group in vivo. Transplantability of the irradiated cells also decreased, whereas survival of tumor-bearing mice increased. Three cell populations with different cytoskeleton structure were identified. After irradiation, the reorganized part of the actin cytoskeleton changed its localization to the submembranous area. A decrease of tumorigenicity in cells irradiated with polychromatic light used in non-damaging doses correlated with an increase in the number of cells with reorganized actin in the submembranous area. The results of the present study argue in favor of the oncological safety of polychromatic VIS-IR light (480-3400 nm).

  11. Stratifying the Develoment of Product Platforms

    DEFF Research Database (Denmark)

    Sköld, Martin; Karlsson, Christer

    2013-01-01

    companies develop platforms for different aims, purposes, and product scopes. Following on from this, the requirements for platform development resources, the ways of organizing platform development, and the implications for management styles have not been explored and are presumably varying. To start...... influencing the project length, requirements for platform development resources, principles for organizing, and implications for management styles....

  12. New offshore platform in the Mexican Gulf

    Energy Technology Data Exchange (ETDEWEB)

    Beisel, T.

    1982-04-01

    After a construction period of only 10 months, the second steel Offshore platform was recently completed in the Mexican Gulf. The pattern for this structure was the Cognac platform. The erection of the new platform, called the 'Cerveza' platform, is described in the article.

  13. Centrifuge-Based Fluidic Platforms

    Science.gov (United States)

    Zoval, Jim; Jia, Guangyao; Kido, Horacio; Kim, Jitae; Kim, Nahui; Madou, Marc

    In this chapter centrifuge-based microfluidic platforms are reviewed and compared with other popular microfluidic propulsion methods. The underlying physical principles of centrifugal pumping in microfluidic systems are presented and the various centrifuge fluidic functions such as valving, decanting, calibration, mixing, metering, heating, sample splitting, and separation are introduced. Those fluidic functions have been combined with analytical measurements techniques such as optical imaging, absorbance and fluorescence spectroscopy and mass spectrometry to make the centrifugal platform a powerful solution for medical and clinical diagnostics and high-throughput screening (HTS) in drug discovery. Applications of a compact disc (CD)-based centrifuge platform analyzed in this review include: two-point calibration of an optode-based ion sensor, an automated immunoassay platform, multiple parallel screening assays and cellular-based assays. The use of modified commercial CD drives for high-resolution optical imaging is discussed as well. From a broader perspective, we compare the technical barriers involved in applying microfluidics for sensing and diagnostic as opposed to applying such techniques to HTS. The latter poses less challenges and explains why HTS products based on a CD fluidic platform are already commercially available, while we might have to wait longer to see commercial CD-based diagnostics.

  14. Platforms for Innovation and Internationalization

    Directory of Open Access Journals (Sweden)

    Erik Stavnsager Rasmussen

    2017-05-01

    Full Text Available The high-tech global startup has many challenges related to both innovation and internationalization. From a Danish cluster of Welfare Tech firms, eight innovative and international firms were selected and interviewed. Such firms typically have to be agile and operate in virtual networks in almost all parts of their value chains. This article contributes to the understanding of how innovation and internationalization to a great extent are interlinked. The firms have developed a core product or service offering, which the firms often describe as “a platform”. Around the platform, they develop their products and services for new customers and users in new countries. The firms have to sustain a strong focus on the platform while at the same time developing their platform solution for new products, new customers, and new markets. This pivoting makes it possible to use the platform in a new context but is highly demanding for the firms. They need to be extremely agile and fast-moving but at the same time still to have a focus on the core of the firm: the platform.

  15. Roles of the cytoskeleton and of Protein Phosphorylation Events in the Osmotic Stress Response in EEL Intestinal Epithelium

    DEFF Research Database (Denmark)

    Lionetto, Maria G; Pedersen, Stine F; Hoffmann, Else K;

    2002-01-01

    phase is bumetanide-insensitive, the second, sustained phase is bumetanide-sensitive, reflecting activation of the apically located Na(+)-K(+)-2Cl(-) (NKCC) cotransporter, which correlates with the cellular RVI response. Here, we investigated the involvement of the cytoskeleton and of serine...... 15%, detectable morphologically mainly as a decrease in the intensity of the apical brush border F-actin labeling.The bumetanide-sensitive response of V(te) and Isc to hypertonicity was potently inhibited by treatment with either cytochalasin, latrunculin A, colchicine, the protein kinase C (PKC...

  16. ADAM12 induces actin cytoskeleton and extracellular matrix reorganization during early adipocyte differentiation by regulating beta1 integrin function

    DEFF Research Database (Denmark)

    Kawaguchi, Nobuko; Sundberg, Christina; Kveiborg, Marie

    2003-01-01

    -100 from cells overexpressing ADAM12 than from control cells. Collectively, these results show that surface expression of ADAM12 impairs the function of beta1 integrins and, consequently, alters the organization of the actin cytoskeleton and extracellular matrix. These events may be necessary....... Moreover, ADAM12-expressing cells were more prone to apoptosis, which could be prevented by treating the cells with beta1-activating antibodies. A reduced and re-organized fibronectin-rich extracellular matrix accompanied these changes. In addition, beta1 integrin was more readily extracted with Triton X...

  17. Proteomic profiling of fibroblasts reveals a modulating effect of extracellular calumenin on the organization of the actin cytoskeleton

    DEFF Research Database (Denmark)

    Jensen, Morten Østergaard; Hansen, Gry Aune; Vorum, Henrik

    2006-01-01

    cytoskeleton and is involved in cytokinesis. Labeling of S phase fibroblasts with bromo-2'deoxy-uridine indicates that calumenin added to the medium also modulates the cell cycle. Our study thus indicates that calumenin possesses a paracrine role on the cells in its vicinity and therefore may be involved...... in the pathophysiology of thrombosis or in wound healing....... but not in normal vasculature. In order to study the possible effects of calumenin extracellularly we used proteomic profiling of fibroblasts cultured in absence as well as in presence of calumenin. Using two-dimensional gel electrophoresis (2-DE) and tandem mass spectrometry (MS/MS) we show that normal fibroblasts...

  18. p38γ regulates the localisation of SAP97 in the cytoskeleton by modulating its interaction with GKAP

    OpenAIRE

    Sabio, Guadalupe; Arthur, James Simon Campbell; Kuma, Yvonne; Peggie, Mark; Carr, Julia; Murray-Tait, Vicky; Centeno, Francisco; Goedert, Michel; Morrice, Nicholas A.; Cuenda, Ana

    2005-01-01

    Activation of the p38 MAP kinase pathways is crucial for the adaptation of mammalian cells to changes in the osmolarity of the environment. Here we identify SAP97/hDlg, the mammalian homologue of the Drosophila tumour suppressor Dlg, as a physiological substrate for the p38γ MAP kinase (SAPK3/p38γ) isoform. SAP97/hDlg is a scaffold protein that forms multiprotein complexes with a variety of proteins and is targeted to the cytoskeleton by its association with the protein guanylate kinase-assoc...

  19. PROcess Based Diagnostics PROBE

    Science.gov (United States)

    Clune, T.; Schmidt, G.; Kuo, K.; Bauer, M.; Oloso, H.

    2013-01-01

    Many of the aspects of the climate system that are of the greatest interest (e.g., the sensitivity of the system to external forcings) are emergent properties that arise via the complex interplay between disparate processes. This is also true for climate models most diagnostics are not a function of an isolated portion of source code, but rather are affected by multiple components and procedures. Thus any model-observation mismatch is hard to attribute to any specific piece of code or imperfection in a specific model assumption. An alternative approach is to identify diagnostics that are more closely tied to specific processes -- implying that if a mismatch is found, it should be much easier to identify and address specific algorithmic choices that will improve the simulation. However, this approach requires looking at model output and observational data in a more sophisticated way than the more traditional production of monthly or annual mean quantities. The data must instead be filtered in time and space for examples of the specific process being targeted.We are developing a data analysis environment called PROcess-Based Explorer (PROBE) that seeks to enable efficient and systematic computation of process-based diagnostics on very large sets of data. In this environment, investigators can define arbitrarily complex filters and then seamlessly perform computations in parallel on the filtered output from their model. The same analysis can be performed on additional related data sets (e.g., reanalyses) thereby enabling routine comparisons between model and observational data. PROBE also incorporates workflow technology to automatically update computed diagnostics for subsequent executions of a model. In this presentation, we will discuss the design and current status of PROBE as well as share results from some preliminary use cases.

  20. Atom probe tomography today

    Directory of Open Access Journals (Sweden)

    Alfred Cerezo

    2007-12-01

    Full Text Available This review aims to describe and illustrate the advances in the application of atom probe tomography that have been made possible by recent developments, particularly in specimen preparation techniques (using dual-beam focused-ion beam instruments but also of the more routine use of laser pulsing. The combination of these two developments now permits atomic-scale investigation of site-specific regions within engineering alloys (e.g. at grain boundaries and in the vicinity of cracks and also the atomic-level characterization of interfaces in multilayers, oxide films, and semiconductor materials and devices.

  1. Experimental probes of axions

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Aaron S.; /Fermilab

    2009-10-01

    Experimental searches for axions or axion-like particles rely on semiclassical phenomena resulting from the postulated coupling of the axion to two photons. Sensitive probes of the extremely small coupling constant can be made by exploiting familiar, coherent electromagnetic laboratory techniques, including resonant enhancement of transitions using microwave and optical cavities, Bragg scattering, and coherent photon-axion oscillations. The axion beam may either be astrophysical in origin as in the case of dark matter axion searches and solar axion searches, or created in the laboratory from laser interactions with magnetic fields. This note is meant to be a sampling of recent experimental results.

  2. Atom Probe Tomography 2012

    Science.gov (United States)

    Kelly, Thomas F.; Larson, David J.

    2012-08-01

    In the world of tomographic imaging, atom probe tomography (APT) occupies the high-spatial-resolution end of the spectrum. It is highly complementary to electron tomography and is applicable to a wide range of materials. The current state of APT is reviewed. Emphasis is placed on applications and data analysis as they apply to many fields of research and development including metals, semiconductors, ceramics, and organic materials. We also provide a brief review of the history and the instrumentation associated with APT and an assessment of the existing challenges in the field.

  3. Mobile Probing Kit

    DEFF Research Database (Denmark)

    Larsen, Jakob Eg; Sørensen, Lene Tolstrup; Sørensen, J.K.

    2007-01-01

    characterized as being highly nomadic and thus potential users of mobile and ubiquitous technologies. The methodology has been applied in the 1ST MAGNET Beyond project in order to obtain user needs and requirements in the process of developing pilot services. We report on the initial findings from applying......Mobile Probing Kit is a low tech and low cost methodology for obtaining inspiration and insights into user needs, requirements and ideas in the early phases of a system's development process. The methodology is developed to identify user needs, requirements and ideas among knowledge workers...

  4. Microfluidics for Positron Emission Tomography Probe Development

    Directory of Open Access Journals (Sweden)

    Ming-Wei Wang

    2010-07-01

    Full Text Available Owing to increased needs for positron emission tomography (PET, high demands for a wide variety of radiolabeled compounds will have to be met by exploiting novel radiochemistry and engineering technologies to improve the production and development of PET probes. The application of microfluidic reactors to perform radiosyntheses is currently attracting a great deal of interest because of their potential to deliver many advantages over conventional labeling systems. Microfluidics-based radiochemistry can lead to the use of smaller quantities of precursors, accelerated reaction rates, and easier purification processes with greater yield and higher specific activity of desired probes. Several proof-of-principle examples along with the basics of device architecture and operation and the potential limitations of each design are discussed. Along with the concept of radioisotope distribution from centralized cyclotron facilities to individual imaging centers and laboratories (“decentralized model”, an easy-to-use, stand-alone, flexible, fully automated, radiochemical microfluidic platform can provide simpler and more cost-effective procedures for molecular imaging using PET.

  5. Platform dependence of inference on gene-wise and gene-set involvement in human lung development

    Directory of Open Access Journals (Sweden)

    Kho Alvin T

    2009-06-01

    Full Text Available Abstract Background With the recent development of microarray technologies, the comparability of gene expression data obtained from different platforms poses an important problem. We evaluated two widely used platforms, Affymetrix U133 Plus 2.0 and the Illumina HumanRef-8 v2 Expression Bead Chips, for comparability in a biological system in which changes may be subtle, namely fetal lung tissue as a function of gestational age. Results We performed the comparison via sequence-based probe matching between the two platforms. "Significance grouping" was defined as a measure of comparability. Using both expression correlation and significance grouping as measures of comparability, we demonstrated that despite overall cross-platform differences at the single gene level, increased correlation between the two platforms was found in genes with higher expression level, higher probe overlap, and lower p-value. We also demonstrated that biological function as determined via KEGG pathways or GO categories is more consistent across platforms than single gene analysis. Conclusion We conclude that while the comparability of the platforms at the single gene level may be increased by increasing sample size, they are highly comparable ontologically even for subtle differences in a relatively small sample size. Biologically relevant inference should therefore be reproducible across laboratories using different platforms.

  6. Persistent Monitoring Platforms Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, C L

    2007-02-22

    This project was inspired and motivated by the need to provide better platforms for persistent surveillance. In the years since the inception of this work, the need for persistence of surveillance platforms has become even more widely appreciated, both within the defense community and the intelligence community. One of the most demanding technical requirements for such a platform involves the power plant and energy storage system, and this project concentrated almost exclusively on the technology associated with this system for a solar powered, high altitude, unmanned aircraft. An important realization for the feasibility of such solar powered aircraft, made at the outset of this project, was that thermal energy may be stored with higher specific energy density than for any other known practical form of rechargeable energy storage. This approach has proved to be extraordinarily fruitful, and a large number of spin-off applications of this technology were developed in the course of this project.

  7. Cerveza platforms offer economic options

    Energy Technology Data Exchange (ETDEWEB)

    Leblanc, L.A.

    1982-08-01

    Two single-piece platforms, Cerveze and Cerveza Ligera, were installed by Union Oil Co. in 925-935 ft of water. The technology and equipment used for the two platforms can be used for units to a depth of 1,400 ft in mild climates and to 1,000 ft in more critical weather areas such as the North Sea. The significant improvements in design and procedures in the construction and installation of the Cerveza Ligera platform are: (1) four leg structure, as opposed to eight, requiring less steel; (2) simplified fabrication; and (3) quicker installation. The most significant area of improvement in the Ligera project compared with Cerveza was in communications. Communications between naval architects and onshore launch foremen during loadout, and between surveyors and tug captains during positioning, are cited as examples.

  8. The bacterial cytoskeleton and its putative role in membrane vesicle formation observed in a Gram-positive bacterium producing starch-degrading enzymes.

    Science.gov (United States)

    Mayer, Frank; Gottschalk, Gerhard

    2003-01-01

    Bacteria may possess various kinds of cytoskeleton. In general, bacterial cytoskeletons may play a role in the control and preservation of the cell shape. Such functions become especially evident when the bacteria do not possess a true wall and are nevertheless elongated (e.g. Mycoplasma spp.) or under extreme cultivation conditions whereby loss of the entire bacterial cell wall takes place. Bacterial cytoskeletons may control and preserve the cell shape only if a number of preconditions are fulfilled. They should be present not only transiently, but permanently, they should be located as a lining close to the inner face of the cytoplasmic membrane, enclosing the entire cytoplasm, and they should comprise structural elements (fibrils) crossing the inner volume of the cell in order to provide the necessary stability for the lining. Complete loss of the cell wall layers had earlier been observed to occur during extensive production of bacterial starch-degrading enzymes in an optimized fermentation process by a Gram-positive bacterium. Even under these conditions, the cells had maintained their elongated shape and full viability. Which of the various kinds of bacterial cytoskeleton might have been responsible for shape preservation? Only one of them, the primary or basic cytoskeleton turns out to fulfil the necessary preconditions listed above. Its structural features now provided a first insight into a possible mechanism of formation of membrane blebs and vesicles as observed in the Gram-positive eubacterium Thermoanaerobacterium thermosulfurogenes EM1, and the putative role of the cytoskeletal web in this process.

  9. Tax Responses in Platform Industries

    DEFF Research Database (Denmark)

    Kind, Hans Jarle; Köthenbürger, Marko; Schjelderup, Guttorm

    Two-sided platform firms serve distinct customer groups that are connected through interdependent demand, and include major businesses such as the media industry, banking, and the software industry. A well known result of tax incidence is that consumers of a more heavily taxed good pay a higher...... price and thus buy less of the good. The present paper shows that this result need not hold in a two-sided market. On the contrary, a higher ad valorem tax may lower end-user prices and spur sales. Thus, two-sided platform firms may not at all engage in tax shifting via price increases. We further show...

  10. Moodle vs. Social Media Platforms

    DEFF Research Database (Denmark)

    Gulieva, Valeria

    Given the competition coming from various social media platforms, it is explored in this paper how students could be encouraged to use Moodle more proactively during their studies. Moodle is a course management system for online learning. It is designed to be a flexible template-based system, which......, known and widely used social platforms. It might be also due to the fact that students do not see the benefits in investing time and efforts in learning the new system. Another reason might be the mandatory nature of Moodle, i.e., it is imposed on students, rather than a free choice – and this might...

  11. A practice scaffolding interactive platform

    DEFF Research Database (Denmark)

    Bundsgaard, Jeppe

    2009-01-01

    , structures the students' activity, and interactively supports subject learning. A PracSIP facilitates students' development of complex competencies, and at the same time it supports the students' development of skills defined in the curriculum. The paper introduces the concept, presents the theoretical......A Practice Scaffolding Interactive Platform (PracSIP) is a social learning platform which supports students in collaborative project based learning by simulating a professional practice. A PracSIP puts the core tools of the simulated practice at the students' disposal, it organizes collaboration...

  12. Screening far red probes for use on optical biochip devices

    Science.gov (United States)

    Njoh, Kerenza L.; Patterson, Laurence H.; Pors, Klaus; Zloh, Mire; Ameer-Beg, Simon; Summers, Huw; Matthews, Daniel; Errington, Rachel J.; Smith, Paul J.

    2006-02-01

    In situ spectral analysis can be used to understand the targeting and interaction of agents in cellular compartments. A range of novel red excitable fluorescent probes, related to the anthraquinone family of anti-cancer agents, were designed for their DNA affinic properties and their ability to enter and penetrate living cells. We report on the spectral features of these probes, both in solution and bound within intact cells, to identify unique fluorescent signatures that exploit their use in bioassays on optical biochip devices. The probes demonstrated red shifted emission spectra and increased 2 photon lifetime, with minimal fluorescent enhancement, upon binding to DNA. Spectral confocal laser scanning microscopy revealed complex emission profiles representing the bound (nuclear) and unbound (cytoplasmic) fractions of the DNA probes within live interphase, mitotic and apoptotic cells. Analysis of the emission peaks encoded the spectra to provide cell compartment recognition and profiles for cells in different cell states. Sampling the entire emission spectra of these probes for cell locating, even in the presence of unbound molecules, provides good signal-to-noise in biochip devices. Furthermore, by sampling the fluorescence output at specific spectral windows we can obtain high spatial information without imaging. The technological challenge is to integrate these fluorophores and appropriate detection capacity onto an optical biochip platform with microfluidic systems for cell handling.

  13. Probing cell structure responses through a shear and stretching mechanical stimulation technique.

    Science.gov (United States)

    Steward, Robert L; Cheng, Chao-Min; Wang, Danny L; LeDuc, Philip R

    2010-04-01

    Cells are complex, dynamic systems that respond to various in vivo stimuli including chemical, mechanical, and scaffolding alterations. The influence of mechanics on cells is especially important in physiological areas that dictate what modes of mechanics exist. Complex, multivariate physiological responses can result from multi-factorial, multi-mode mechanics, including tension, compression, or shear stresses. In this study, we present a novel device based on elastomeric materials that allowed us to stimulate NIH 3T3 fibroblasts through uniaxial strip stretching or shear fluid flow. Cell shape and structural response was observed using conventional approaches such as fluorescent microscopy. Cell orientation and actin cytoskeleton alignment along the direction of applied force were observed to occur after an initial 3 h time period for shear fluid flow and static uniaxial strip stretching experiments although these two directions of alignment were oriented orthogonal relative to each other. This response was then followed by an increasingly pronounced cell and actin cytoskeleton alignment parallel to the direction of force after 6, 12, and 24 h, with 85% of the cells aligned along the direction of force after 24 h. These results indicate that our novel device could be implemented to study the effects of multiple modes of mechanical stimulation on living cells while probing their structural response especially with respect to competing directions of alignment and orientation under these different modes of mechanical stimulation. We believe that this will be important in a diversity of fields including cell mechanotransduction, cell-material interactions, biophysics, and tissue engineering.

  14. Mammalian adenylyl cyclase-associated protein 1 (CAP1) regulates cofilin function, the actin cytoskeleton, and cell adhesion.

    Science.gov (United States)

    Zhang, Haitao; Ghai, Pooja; Wu, Huhehasi; Wang, Changhui; Field, Jeffrey; Zhou, Guo-Lei

    2013-07-19

    CAP (adenylyl cyclase-associated protein) was first identified in yeast as a protein that regulates both the actin cytoskeleton and the Ras/cAMP pathway. Although the role in Ras signaling does not extend beyond yeast, evidence supports that CAP regulates the actin cytoskeleton in all eukaryotes including mammals. In vitro actin polymerization assays show that both mammalian and yeast CAP homologues facilitate cofilin-driven actin filament turnover. We generated HeLa cells with stable CAP1 knockdown using RNA interference. Depletion of CAP1 led to larger cell size and remarkably developed lamellipodia as well as accumulation of filamentous actin (F-actin). Moreover, we found that CAP1 depletion also led to changes in cofilin phosphorylation and localization as well as activation of focal adhesion kinase (FAK) and enhanced cell spreading. CAP1 forms complexes with the adhesion molecules FAK and Talin, which likely underlie the cell adhesion phenotypes through inside-out activation of integrin signaling. CAP1-depleted HeLa cells also had substantially elevated cell motility as well as invasion through Matrigel. In summary, in addition to generating in vitro and in vivo evidence further establishing the role of mammalian CAP1 in actin dynamics, we identified a novel cellular function for CAP1 in regulating cell adhesion.

  15. Jak3 enables chemokine-dependent actin cytoskeleton reorganization by regulating cofilin and Rac/Rhoa GTPases activation.

    Directory of Open Access Journals (Sweden)

    Xochitl Ambriz-Peña

    Full Text Available We have previously shown that Jak3 is involved in the signaling pathways of CCR7, CCR9 and CXCR4 in murine T lymphocytes and that Jak3⁻/⁻ lymphocytes display an intrinsic defect in homing to peripheral lymph nodes. However, the molecular mechanism underlying the defective migration observed in Jak3⁻/⁻ lymphocytes remains elusive. Here, it is demonstrated for the first time, that Jak3 is required for the actin cytoskeleton reorganization in T lymphocytes responding to chemokines. It was found that Jak3 regulates actin polymerization by controlling cofilin inactivation in response to CCL21 and CXCL12. Interestingly, cofilin inactivation was not precluded in PTX- treated cells despite their impaired actin polymerization. Additionally, Jak3 was required for small GTPases Rac1 and RhoA activation, which are indispensable for acquisition of the migratory cell phenotype and the generation of a functional leading edge and uropod, respectively. This defect correlates with data obtained by time-lapse video-microscopy showing an incompetent uropod formation and impaired motility in Jak3-pharmacologically inhibited T lymphocytes. Our data support a new model in which Jak3 and heterotrimeric G proteins can use independent, but complementary, signaling pathways to regulate actin cytoskeleton dynamics during cell migration in response to chemokines.

  16. Simulated microgravity alters the expression of cytoskeleton- and ATP-binding-related genes in MLO-Y4 osteocytes

    Science.gov (United States)

    Chen, Zhihao; Zhao, Fan; Qi, Yiduo; Hu, Lifang; Li, Dijie; Yin, Chong; Su, Peihong; Zhang, Yan; Ma, Jianhua; Qian, Jing; Zhou, Hongpo; Zou, Yiwei; Qian, Airong

    2016-12-01

    Bone undergoes dynamic modelling and remodelling processes, and it requires gravity-mediated mechanical stimulation for the maintenance of mineral content and structure. Osteocytes are the most commonly found cells in the mature bone, and they are sensitive to mechanical changes. The purpose of this study was to investigate the effects of microgravity simulated with a random position machine (RPM) on the gene expression profile of osteocytes. Genes sensitive to RPM treatment were sorted on the basis of biological processes, interactions and signalling pathways. Overall, 504 differentially expressed genes (DEGs) in osteocytes cultured under RPM conditions were found. The DEGs were further analysed using bioinformatics tools such as DAVID and iReport. A total of 15 ATP-binding and cytoskeleton-related genes were further confirmed by quantitative real-time PCR (qRT-PCR). Our findings demonstrate that the RPM affected the expression of genes involved in cytoskeleton remodelling and the energy-transfer process in osteocytes. The identification of mechanosensitive genes may enhance our understanding of the roles of osteocytes in mechanosensation and may provide some potential targets for preventing and treating bone-related diseases.

  17. Fluxes of water through aquaporin 9 weaken membrane-cytoskeleton anchorage and promote formation of membrane protrusions.

    Directory of Open Access Journals (Sweden)

    Thommie Karlsson

    Full Text Available All modes of cell migration require rapid rearrangements of cell shape, allowing the cell to navigate within narrow spaces in an extracellular matrix. Thus, a highly flexible membrane and a dynamic cytoskeleton are crucial for rapid cell migration. Cytoskeleton dynamics and tension also play instrumental roles in the formation of different specialized cell membrane protrusions, viz. lamellipodia, filopodia, and membrane blebs. The flux of water through membrane-anchored water channels, known as aquaporins (AQPs has recently been implicated in the regulation of cell motility, and here we provide novel evidence for the role of AQP9 in the development of various forms of membrane protrusion. Using multiple imaging techniques and cellular models we show that: (i AQP9 induced and accumulated in filopodia, (ii AQP9-associated filopodial extensions preceded actin polymerization, which was in turn crucial for their stability and dynamics, and (iii minute, local reductions in osmolarity immediately initiated small dynamic bleb-like protrusions, the size of which correlated with the reduction in osmotic pressure. Based on this, we present a model for AQP9-induced membrane protrusion, where the interplay of water fluxes through AQP9 and actin dynamics regulate the cellular protrusive and motile activity of cells.

  18. p130Cas Couples the tyrosine kinase Bmx/Etk with regulation of the actin cytoskeleton and cell migration.

    Science.gov (United States)

    Abassi, Yama A; Rehn, Marko; Ekman, Niklas; Alitalo, Kari; Vuori, Kristiina

    2003-09-12

    Bmx/Etk, a member of the Tec/Btk family of nonreceptor kinases, has recently been shown to mediate cell motility in signaling pathways that become activated upon integrin-mediated cell adhesion (Chen, R., Kim, O., Li, M., Xiong, X., Guan, J. L., Kung, H. J., Chen, H., Shimizu, Y., and Qiu, Y. (2001) Nat Cell Biol. 3, 439-444). The molecular mechanisms of Bmx-induced cell motility have so far remained unknown. Previous studies by us and others have demonstrated that a complex formation between the docking protein p130Cas (Cas) and the adapter protein Crk is instrumental in connecting several stimuli to the regulation of actin cytoskeleton and cell motility. We demonstrate here that expression of Bmx leads to an interaction between Bmx and Cas at membrane ruffles, which are sites of active actin remodeling in motile cells. Expression of Bmx also enhances tyrosine phosphorylation of Cas and Cas.Crk complex formation, and coexpression of Bmx with Cas results in an enhanced membrane ruffling and haptotactic cell migration. Importantly, a mutant form of Bmx that fails to interact with Cas also fails to induce cell migration. Furthermore, expression of a dominant-negative form of Cas that is incapable of interacting with Crk inhibits Bmx-induced membrane ruffling and cell migration. These studies suggest that Bmx-Cas interaction, phosphorylation of Cas by Bmx, and subsequent Cas.Crk complex formation functionally couple Bmx to the regulation of actin cytoskeleton and cell motility.

  19. Single-Cell Mechanics Provides an Effective Means To Probe in Vivo Interactions between Alveolar Macrophages and Silver Nanoparticles.

    Science.gov (United States)

    Liu, Ying X; Karsai, Arpad; Anderson, Donald S; Silva, Rona M; Uyeminami, Dale L; Van Winkle, Laura S; Pinkerton, Kent E; Liu, Gang-yu

    2015-12-10

    Single-cell mechanics, derived from atomic force microscopy-based technology, provides a new and effective means to investigate nanomaterial-cell interactions upon in vivo exposure. Lung macrophages represent initial and important responses upon introducing nanoparticles into the respiratory tract, as well as particle clearance with time. Cellular mechanics has previously proven effective to probe in vitro nanomaterial-cell interactions. This study extends technology further to probe the interactions between primary alveolar macrophages (AM) and silver nanoparticles (AgNPs) upon in vivo exposure. Two types of AgNPs, 20 and 110 nm, were instilled to rat lung at 0.5 mg AgNPs/kg body weight, and allowed 24 h interaction. The consequences of these interactions were investigated by harvesting the primary AMs while maintaining their biological status. Cellular mechanics measurements revealed the diverse responses among AM cells, due to variations in AgNP uptake and oxidative dissolving into Ag(+). Three major responses are evident: zero to low uptake that does not alter cellular mechanics, intracellular accumulation of AgNPs trigger cytoskeleton rearrangement resulting in the stiffening of mechanics, and damage of cytoskeleton that softens the mechanical profile. These effects were confirmed using confocal imaging of F-actin and measurements of reactive oxygen species production. More detailed intracellular interactions will also be discussed on the basis of this study in conjunction with prior knowledge of AgNP toxicity.

  20. The Antartic Ice Borehole Probe

    Science.gov (United States)

    Behar, A.; Carsey, F.; Lane, A.; Engelhardt, H.

    2000-01-01

    The Antartic Ice Borehole Probe mission is a glaciological investigation, scheduled for November 2000-2001, that will place a probe in a hot-water drilled hole in the West Antartic ice sheet. The objectives of the probe are to observe ice-bed interactions with a downward looking camera, and ice inclusions and structure, including hypothesized ice accretion, with a side-looking camera.

  1. Effect of the disruption of three cytoskeleton components on chondrocyte metabolism in rabbit knee cartilage

    Institute of Scientific and Technical Information of China (English)

    Duan Wangping; Wei Lei; Cao Xiaoming; Guo Heng; Wang Lei; Hao Yongzhuang; Wei Xiaochun

    2014-01-01

    Background Chondrocytes' phenotype and biosynthesis of matrix are dependent on having an intact cytoskeletal structure.Microfilaments,microtubules,and intermediate filaments are three important components of the cytoskeletal structure of chondrocytes.The aims of this study were to determine and compare the effects of the disruption of these three cytoskeletal elements on the apoptosis and matrix synthesis by rabbit knee chondrocytes in vitro.Methods Chondrocytes were isolated from full-thickness knee cartilage of two-month-old rabbits using enzymatic methods (n=24).The isolated cells were stabilized for three days and then exposed to low,medium,and high doses of chemical agents that disrupt the three principal cytoskeletal elements of interest:colchicine for microtubules,acrylamide for intermediate filaments,and cytochalasin D for actin microfilaments.A group of control cells were treated with carrier.Early apoptosis was assessed using the Annexin-FITC binding assay by flow cytometry on days 1 and 2 after exposure to the disrupting chemical agents.The components and distribution of the cytoskeleton within the cells were analyzed by laser scanning confocal microscopy (LSCM) with immunofluorescence staining on day 3.The mRNA levels of aggrecan (AGG) and type Ⅱ collagen (Col-2) and their levels in culture medium were analyzed using real-time PCR and enzymelinked immunosorbent serologic assay (ELISA) on days 3,6,and 9.Results In the initial drug-dose-response study,there was no significant difference in the vitality of cells treated with 0.1 μmol/L colchicine,2.5 mmol/L acrylamide,and 10 μg/L cytochalasin D for two days when compared with the control group of cells.The concentrations of colchicine and acrylamide treatment selected above significantly decreased the number of viable cells over the nine-day culture and disrupted significantly more cell nuclei.Real-time PCR and ELISA results showed that the mRNA levels and medium concentrations of AGG and Col-2 were

  2. 2009 Analysis Platform Review Report

    Energy Technology Data Exchange (ETDEWEB)

    Ferrell, John [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States

    2009-12-01

    This document summarizes the recommendations and evaluations provided by an independent external panel of experts at the U.S. Department of Energy Biomass Program’s Analysis platform review meeting, held on February 18, 2009, at the Marriott Residence Inn, National Harbor, Maryland.

  3. 2009 Infrastructure Platform Review Report

    Energy Technology Data Exchange (ETDEWEB)

    Ferrell, John [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

    2009-12-01

    This document summarizes the recommendations and evaluations provided by an independent external panel of experts at the U.S. Department of Energy Biomass program‘s Infrastructure platform review meeting, held on February 19, 2009, at the Marriott Residence Inn, National Harbor, Maryland.

  4. Venus Atmospheric Maneuverable Platform (VAMP)

    Science.gov (United States)

    Polidan, R.; Lee, G.; Sokol, D.; Griffin, K.; Bolisay, L.

    2014-05-01

    VAMP is a long lived, semi-buoyant, atmospheric “rover” that deploys in orbit, enters the Venus atmosphere and flies in the Venus atmosphere between 55 and 70 km for up to one year as a platform to address VEXAG goals I.A, I.B, and I.C.

  5. Utilizing platforms in industrialized construction

    DEFF Research Database (Denmark)

    Bonev, Martin; Wörösch, Michael; Hvam, Lars

    2015-01-01

    Purpose – The purpose of this paper is to explore the development of a platform-based projectexecution in the industrialised construction sector, with a focus on systematically balancing cost andvalue. Offering custom-tailored buildings at reasonable costs has been a growing concern for manyconst...

  6. Generational Transitions in Platform Markets

    DEFF Research Database (Denmark)

    Kretschmer, Tobias; Claussen, Jörg

    2016-01-01

    The introduction of a new product generation forces incumbents in platform markets to rebuild their installed base of complementary products. Using three different data sets on the U.S. market for video game consoles, we show that incumbents can, to some extent, substitute for rebuilding their new...

  7. Analysis of offshore jacket platform

    Digital Repository Service at National Institute of Oceanography (India)

    Harish, N.; Mandal, S.; Shanthala, B.; Rao, S.

    -Rohman, M., ‘Multi-loop feedback control of offshore steel jacket platforms’, Computers & Structures 70, 1999, 185–202. 11.Yamamoto, I., Terada, Y., and Yokokura, K., ‘An application of a position keeping control system to floating offshore platform...

  8. Tax Responses in Platform Industries

    DEFF Research Database (Denmark)

    Kind, Hans Jarle; Köthenbürger, Marko; Schjelderup, Guttorm

    Two-sided platform firms serve distinct customer groups that are connected through interdependent demand, and include major businesses such as the media industry, banking, and the software industry. A well known result of tax incidence is that consumers of a more heavily taxed good pay a higher...

  9. 2009 Feedstocks Platform Review Report

    Energy Technology Data Exchange (ETDEWEB)

    Ferrell, John [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

    2009-12-01

    This document summarizes the recommendations and evaluations provided by an independent external panel of experts at the U.S. Department of Energy Biomass Program‘s Feedstock platform review meeting, held on April 8–10, 2009, at the Grand Hyatt Washington, Washington, D.C.

  10. The cell morphogenesis gene ANGUSTIFOLIA encodes a CtBP/BARS-like protein and is involved in the control of the microtubule cytoskeleton.

    Science.gov (United States)

    Folkers, U; Kirik, V; Schöbinger, U; Falk, S; Krishnakumar, S; Pollock, M A; Oppenheimer, D G; Day, I; Reddy, A S M; Jürgens, G; Hülskamp, M; Reddy, A R

    2002-03-15

    The ANGUSTIFOLIA (AN) gene is required for leaf hair (trichome) branching and is also involved in polarized expansion underlying organ shape. Here we show that the AN gene encodes a C-terminal binding proteins/brefeldin A ADP-ribosylated substrates (CtBP/BARS) related protein. AN is expressed at low levels in all organs and the AN protein is localized in the cytoplasm. In an mutant trichomes, the organization of the actin cytoskeleton is normal but the distribution of microtubules is aberrant. A role of AN in the control of the microtubule cytoskeleton is further supported by the finding that AN genetically and physically interacts with ZWICHEL, a kinesin motor molecule involved in trichome branching. Our data suggest that CtBP/BARS-like protein function in plants is directly associated with the microtubule cytoskeleton.

  11. What is the most sensitive measure of water maze probe test performance?

    Directory of Open Access Journals (Sweden)

    Hamid R Maei

    2009-03-01

    Full Text Available The water maze is commonly used to assay spatial cognition, or, more generally, learning and memory in experimental rodent models. In the water maze, mice or rats are trained to navigate to a platform located below the water’s surface. Spatial learning is then typically assessed in a probe test, where the platform is removed from the pool and the mouse or rat is allowed to search for it. Performance in the probe test may then be evaluated using either occupancy-based (percent time in virtual quadrant [Q] or zone [Z] centered on former platform location, error-based (mean proximity to former platform location [P] or counting-based (platform crossings [X] measures. While these measures differ in their popularity, whether they differ in their ability to detect group differences is not known. To address this question we compiled 5 separate databases, containing more than 1600 mouse probe tests. Random selection of individual trials from respective databases then allowed us to simulate experiments with varying sample and effect sizes. Using this Monte Carlo-based method, we found that the P measure consistently outperformed the Q, Z and X measures in its ability to detect group differences. This was the case regardless of sample or effect size, and using both parametric and non-parametric statistical analyses. The relative superiority of P over other commonly used measures suggests that it is the most appropriate measure to employ in both low- and high-throughput water maze screens.

  12. Multiplexed, rapid point of care platform to quantify allergen-specific IgE.

    Science.gov (United States)

    Monroe, M R; Reddington, A P; Cretich, M; Chiari, M; Little, F; Ünlü, M S

    2011-01-01

    Variation of probe immobilization on microarrays hinders the ability to make high quality, assertive and statistically relevant conclusions needed in the healthcare setting. To address this problem, we have developed a calibrated, compact, inexpensive, multiplexed, dual modality point-of-care detection platform that calibrates and correlates surface probe density measured label-free to captured labeled secondary antibody, is independent of chip-to-chip variability, and improves upon existing diagnostic technology. We have identified four major technological advantages of our proposed platform: the capability to perform single spot analysis based on the fluorophore used for detection, a 10-fold gain in fluorescence signal due to optimized substrate, a calibrated, quantitative method that uses the combined fluorescent and label-free modalities to accurately measure the density of probe and bound target for a variety of systems, and a compact measurement platform offering reliable and rapid results at the doctor's office. Already, we have formulated over a 90% linear correlation between the amount of probe bound to surface and the resulting fluorescence of captured target for IgG, β-lactoglobulin, Ara h 1 peanut allergen, and Phl 5a Timothy grass allergen.

  13. Multiple membrane tethers probed by atomic force microscopy.

    Science.gov (United States)

    Sun, Mingzhai; Graham, John S; Hegedüs, Balazs; Marga, Françoise; Zhang, Ying; Forgacs, Gabor; Grandbois, Michel

    2005-12-01

    Using the atomic force microscope to locally probe the cell membrane, we observed the formation of multiple tethers (thin nanotubes, each requiring a similar pulling force) as reproducible features within force profiles recorded on individual cells. Forces obtained with Chinese hamster ovary cells, a malignant human brain tumor cell line, and human endothelial cells (EA hy926) were found to be 28 +/- 10 pN, 29 +/- 9 pN, and 29 +/- 10 pN, respectively, independent of the nature of attachment to the cantilever. The rather large variation of the tether pulling forces measured at several locations on individual cells points to the existence of heterogeneity in the membrane properties of a morphologically homogeneous cell. Measurement of the summary lengths of the simultaneously extracted tethers provides a measure of the size of the available membrane reservoir through which co-existing tethers are associated. As expected, partial disruption of the actin cytoskeleton and removal of the hyaluronan backbone of the glycocalyx were observed to result in a marked decrease (30-50%) in the magnitude and a significant sharpening of the force distribution indicating reduced heterogeneity of membrane properties. Taken together, our results demonstrate the ability of the plasma membrane to locally produce multiple interdependent tethers-a process that could play an important role in the mechanical association of cells with their environment.

  14. Cosmological Probes for Supersymmetry

    Directory of Open Access Journals (Sweden)

    Maxim Khlopov

    2015-05-01

    Full Text Available The multi-parameter character of supersymmetric dark-matter models implies the combination of their experimental studies with astrophysical and cosmological probes. The physics of the early Universe provides nontrivial effects of non-equilibrium particles and primordial cosmological structures. Primordial black holes (PBHs are a profound signature of such structures that may arise as a cosmological consequence of supersymmetric (SUSY models. SUSY-based mechanisms of baryosynthesis can lead to the possibility of antimatter domains in a baryon asymmetric Universe. In the context of cosmoparticle physics, which studies the fundamental relationship of the micro- and macro-worlds, the development of SUSY illustrates the main principles of this approach, as the physical basis of the modern cosmology provides cross-disciplinary tests in physical and astronomical studies.

  15. Cosmological Probes for Supersymmetry

    CERN Document Server

    Khlopov, Maxim

    2015-01-01

    The multi-parameter character of supersymmetric dark-matter models implies the combination of their experimental studies with astrophysical and cosmological probes. The physics of the early Universe provides nontrivial effects of non-equilibrium particles and primordial cosmological structures. Primordial black holes (PBHs) are a profound signature of such structures that may arise as a cosmological consequence of supersymmetric (SUSY) models. SUSY-based mechanisms of baryosynthesis can lead to the possibility of antimatter domains in a baryon asymmetric Universe. In the context of cosmoparticle physics, which studies the fundamental relationship of the micro- and macro-worlds, the development of SUSY illustrates the main principles of this approach, as the physical basis of the modern cosmology provides cross-disciplinary tests in physical and astronomical studies.

  16. Spontaneous Symmetry Probing

    CERN Document Server

    Nicolis, Alberto

    2011-01-01

    For relativistic quantum field theories, we consider Lorentz breaking, spatially homogeneous field configurations or states that evolve in time along a symmetry direction. We dub this situation "spontaneous symmetry probing" (SSP). We mainly focus on internal symmetries, i.e. on symmetries that commute with the Poincare group. We prove that the fluctuations around SSP states have a Lagrangian that is explicitly time independent, and we provide the field space parameterization that makes this manifest. We show that there is always a gapless Goldstone excitation that perturbs the system in the direction of motion in field space. Perhaps more interestingly, we show that if such a direction is part of a non-Abelian group of symmetries, the Goldstone bosons associated with spontaneously broken generators that do not commute with the SSP one acquire a gap, proportional to the SSP state's "speed". We outline possible applications of this formalism to inflationary cosmology.

  17. New probe of naturalness.

    Science.gov (United States)

    Craig, Nathaniel; Englert, Christoph; McCullough, Matthew

    2013-09-20

    Any new scalar fields that perturbatively solve the hierarchy problem by stabilizing the Higgs boson mass also generate new contributions to the Higgs boson field-strength renormalization, irrespective of their gauge representation. These new contributions are physical, and in explicit models their magnitude can be inferred from the requirement of quadratic divergence cancellation; hence, they are directly related to the resolution of the hierarchy problem. Upon canonically normalizing the Higgs field, these new contributions lead to modifications of Higgs couplings that are typically great enough that the hierarchy problem and the concept of electroweak naturalness can be probed thoroughly within a precision Higgs boson program. Specifically, at a lepton collider this can be achieved through precision measurements of the Higgs boson associated production cross section. This would lead to indirect constraints on perturbative solutions to the hierarchy problem in the broadest sense, even if the relevant new fields are gauge singlets.

  18. Advanced Langmuir Probe (LP)

    Science.gov (United States)

    Voronka, N. R.; Block, B. P.; Carignan, G. R.

    1991-01-01

    The dynamic response of the MK-2 version of the Langmuir probe amplifier was studied. The settling time of the step response is increased by: (1) stray node-to-ground capacitance at series connections between high value feedback resistors; and (2) input capacitance due to the input cable, FET switches, and input source follower. The stray node-to-ground capacitances can be reduced to tolerable levels by elevating the string of feedback resistors above the printing board. A new feedback network was considered, with promising results. The design uses resistances having much lower nominal values, thereby minimizing the effect of stray capacitances. Faster settling times can be achieved by using an operational amplifier having a higher gain-bandwidth product.

  19. Probe-based Real-time PCR Approaches for Quantitative Measurement of microRNAs

    Science.gov (United States)

    Wong, Wilson; Farr, Ryan; Joglekar, Mugdha; Januszewski, Andrzej; Hardikar, Anandwardhan

    2015-01-01

    Probe-based quantitative PCR (qPCR) is a favoured method for measuring transcript abundance, since it is one of the most sensitive detection methods that provides an accurate and reproducible analysis. Probe-based chemistry offers the least background fluorescence as compared to other (dye-based) chemistries. Presently, there are several platforms available that use probe-based chemistry to quantitate transcript abundance. qPCR in a 96 well plate is the most routinely used method, however only a maximum of 96 samples or miRNAs can be tested in a single run. This is time-consuming and tedious if a large number of samples/miRNAs are to be analyzed. High-throughput probe-based platforms such as microfluidics (e.g. TaqMan Array Card) and nanofluidics arrays (e.g. OpenArray) offer ease to reproducibly and efficiently detect the abundance of multiple microRNAs in a large number of samples in a short time. Here, we demonstrate the experimental setup and protocol for miRNA quantitation from serum or plasma-EDTA samples, using probe-based chemistry and three different platforms (96 well plate, microfluidics and nanofluidics arrays) offering increasing levels of throughput. PMID:25938938

  20. Direct Intracellular Delivery of Cell-Impermeable Probes of Protein Glycosylation by Using Nanostraws.

    Science.gov (United States)

    Xu, Alexander M; Wang, Derek S; Shieh, Peyton; Cao, Yuhong; Melosh, Nicholas A

    2017-04-04

    Bioorthogonal chemistry is an effective tool for elucidating metabolic pathways and measuring cellular activity, yet its use is currently limited by the difficulty of getting probes past the cell membrane and into the cytoplasm, especially if more complex probes are desired. Here we present a simple and minimally perturbative technique to deliver functional probes of glycosylation into cells by using a nanostructured "nanostraw" delivery system. Nanostraws provide direct intracellular access to cells through fluid conduits that remain small enough to minimize cell perturbation. First, we demonstrate that our platform can deliver an unmodified azidosugar, N-azidoacetylmannosamine, into cells with similar effectiveness to a chemical modification strategy (peracetylation). We then show that the nanostraw platform enables direct delivery of an azidosugar modified with a charged uridine diphosphate group (UDP) that prevents intracellular penetration, thereby bypassing multiple enzymatic processing steps. By effectively removing the requirement for cell permeability from the probe, the nanostraws expand the toolbox of bioorthogonal probes that can be used to study biological processes on a single, easy-to-use platform. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.