General Aspects of Two-Component Regulatory Circuits in Bacteria: Domains, Signals and Roles.

PubMed

Padilla-Vaca, Felipe; Mondragón-Jaimes, Verónica; Franco, Bernardo

2017-01-01

All living organisms are subject to changing environments, which must be sensed in order to respond swiftly and efficiently. Two-component systems (TCS) are signal transduction regulatory circuits based typically on a membrane bound sensor kinase and a cytoplasmic response regulator, that is activated through a histidine to aspartate phosphorelay reactions. Activated response regulator acts usually as a transcription factor. The best known examples were identified in bacteria, but they are also found in fungi, algae and plants. Thus far, they are not found in mammals. Regulatory circuits coupled to two-component systems exhibit a myriad of responses to environmental stimuli such as: redox potential, pH, specific metabolites, pressure, light and more recently to specific antimicrobial peptides that activate a sensor kinase responsible for expressing virulence factors through the active response regulator. In this review we explore general aspects on two-component systems that ultimately can play a role on virulence regulation, also the intriguing domain properties of the sensor kinases that can be a potential target for antimicrobial compounds. Only a handful of sensor kinases are extensively characterized, the vast majority belong to what we call 'the dark matter of bacterial signal transduction' since no known signal, structure and biochemical properties are available. Regulatory circuits from vertebrate pathogenic organisms can explain virulence in terms of either response to environmental factors or specific niche occupancy. Hopefully, knowledge on these signal transduction systems can lead to identify novel molecules that target two-component systems, since the increase of drug resistant microorganisms is worrisome. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Magnetic orientation in C. elegans relies on the integrity of the villi of the AFD magnetosensory neurons.

PubMed

Bainbridge, Chance; Rodriguez, Anjelica; Schuler, Andrew; Cisneros, Michael; Vidal-Gadea, Andrés G

2016-10-01

The magnetic field of the earth provides many organisms with sufficient information to successfully navigate through their environments. While evidence suggests the widespread use of this sensory modality across many taxa, it remains an understudied sensory modality. We have recently showed that the nematode C. elegans orients to earth-strength magnetic fields using the first pair of described magnetosensory neurons, AFDs. The AFD cells are a pair of ciliated sensory neurons crowned by fifty villi known to be implicated in temperature sensation. We investigated the potential importance of these subcellular structures for the performance of magnetic orientation. We show that ciliary integrity and villi number are essential for magnetic orientation. Mutants with impairments AFD cilia or villi structure failed to orient to magnetic fields. Similarly, C. elegans larvae possessing immature AFD neurons with fewer villi were also unable to orient to magnetic fields. Larvae of every stage however retained the ability to orient to thermal gradients. To our knowledge, this is the first behavioral separation of magnetic and thermal orientation in C. elegans. We conclude that magnetic orientation relies on the function of both cilia and villi in the AFD neurons. The role of villi in multiple sensory transduction pathways involved in the sensory transduction of vectorial stimuli further supports the likely role of the villi of the AFD neurons as the site for magnetic field transduction. The genetic and behavioral tractability of C. elegans make it a promising system for uncovering potentially conserved molecular mechanisms by which animals across taxa detect and orient to magnetic fields. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of environmental variation during seed production on seed dormancy and germination.

PubMed

Penfield, Steven; MacGregor, Dana R

2017-02-01

The environment during seed production has major impacts on the behaviour of progeny seeds. It can be shown that for annual plants temperature perception over the whole life history of the mother can affect the germination rate of progeny, and instances have been documented where these affects cross whole generations. Here we discuss the current state of knowledge of signal transduction pathways controlling environmental responses during seed production, focusing both on events that take place in the mother plant and those that occur directly as a result of environmental responses in the developing zygote. We show that seed production environment effects are complex, involving overlapping gene networks active independently in fruit, seed coat, and zygotic tissues that can be deconstructed using careful physiology alongside molecular and genetic experiments. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

[Signal transduction mechanisms of hormones through membrane receptors].

PubMed

Yasufuku-Takano, Junko; Takano, Koji

2002-02-01

Hormones exert their effect on cells either via membrane receptors or intracellular receptors. This paper aims to review membrane receptors and the intracellular signal transduction mechanisms. Membrane receptors could be classified according to their structural characteristics and the way they initiate the intracellular signal transduction. These include 1) Seven transmembrane(or G-protein coupled) receptors--heterotrimeric G-proteins--effector, system, 2) Receptor tyrosine kinases--protein-protein interaction through SH2, SH3, and PTB domain--MAP kinase cascades and PI3-kinase pathways, 3) Cytokine receptors--JAK--STAT pathways, 4) Receptors of the TGF- beta superfamily--SMAD pathways, 5) Apoptosis-related receptors--caspase pathways, and 6) ligand-gated ion channels. There are growing knowledge of cross-talks between these pathways. It is being recognized that steroid hormones have distinct membrane receptors, which mediate rapid, nongenomic effect.

From receptor binding kinetics to signal transduction; a missing link in predicting in vivo drug-action.

PubMed

Nederpelt, Indira; Kuzikov, Maria; de Witte, Wilbert E A; Schnider, Patrick; Tuijt, Bruno; Gul, Sheraz; IJzerman, Adriaan P; de Lange, Elizabeth C M; Heitman, Laura H

2017-10-26

An important question in drug discovery is how to overcome the significant challenge of high drug attrition rates due to lack of efficacy and safety. A missing link in the understanding of determinants for drug efficacy is the relation between drug-target binding kinetics and signal transduction, particularly in the physiological context of (multiple) endogenous ligands. We hypothesized that the kinetic binding parameters of both drug and endogenous ligand play a crucial role in determining cellular responses, using the NK1 receptor as a model system. We demonstrated that the binding kinetics of both antagonists (DFA and aprepitant) and endogenous agonists (NKA and SP) have significantly different effects on signal transduction profiles, i.e. potency values, in vitro efficacy values and onset rate of signal transduction. The antagonistic effects were most efficacious with slowly dissociating aprepitant and slowly associating NKA while the combination of rapidly dissociating DFA and rapidly associating SP had less significant effects on the signal transduction profiles. These results were consistent throughout different kinetic assays and cellular backgrounds. We conclude that knowledge of the relationship between in vitro drug-target binding kinetics and cellular responses is important to ultimately improve the understanding of drug efficacy in vivo.

A Prize-Collecting Steiner Tree Approach for Transduction Network Inference

NASA Astrophysics Data System (ADS)

Bailly-Bechet, Marc; Braunstein, Alfredo; Zecchina, Riccardo

Into the cell, information from the environment is mainly propagated via signaling pathways which form a transduction network. Here we propose a new algorithm to infer transduction networks from heterogeneous data, using both the protein interaction network and expression datasets. We formulate the inference problem as an optimization task, and develop a message-passing, probabilistic and distributed formalism to solve it. We apply our algorithm to the pheromone response in the baker’s yeast S. cerevisiae. We are able to find the backbone of the known structure of the MAPK cascade of pheromone response, validating our algorithm. More importantly, we make biological predictions about some proteins whose role could be at the interface between pheromone response and other cellular functions.

[Transduction peptides, the useful face of a new signaling mechanism].

PubMed

Joliot, Alain; Prochiantz, Alain

2005-03-01

Transduction peptides that cross the plasma membrane of live cells are commonly used for the in vitro and in vivo targeting of hydrophilic drugs into the cell interior. Although this family of peptides has recently increased and will probably continue to do so, the two mainly used peptides are derived from transcription factors. Indeed, TAT is a 12 amino acid long arginine-rich peptide present in the HIV transcription factor, and penetratin - or its variants - corresponds to 16 amino acids that define the highly conserved third helix of the DNA-binding domain (homeodomain) of homeoprotein transcription factors. In this review, we shall recall the different steps that have led to the discovery of transduction peptides and present the most likely hypotheses concerning the mechanisms involved in their internalization. At the risk of being incomplete or, even, biased, we shall concentrate on penetratins and TAT. The reason is that these peptides have been studied for over ten years leading to the edification of robust knowledge regarding their properties. This attitude will not preclude comparisons with other peptides, if necessary. Our goal is to describe the mode of action of these transduction peptides, their range of activity in term of cell types that accept them and cargoes that they can transport, and, also, some of the limitations that one can encounter in their use. Finally, based on the idea that peptide transduction is the technological face of a physiological property of some transcription factors, we shall discuss the putative physiological function of homeoprotein transduction, and, as a consequence, the possibility to use these factors as therapeutic proteins.

Revisiting Theories of Humidity Transduction: A Focus on Electrophysiological Data.

PubMed

Tichy, Harald; Hellwig, Maria; Kallina, Wolfgang

2017-01-01

Understanding the mechanism of humidity transduction calls for experimental data and a theory to interpret the data and design new experiments. A comprehensive theory of humidity transduction must start with agreement on what humidity parameters are measured by hygroreceptors and processed by the brain. Hygroreceptors have been found in cuticular sensilla of a broad range of insect species. Their structural features are far from uniform. Nevertheless, these sensilla always contain an antagonistic pair of a moist cell and a dry cell combined with a thermoreceptive cold cell. The strategy behind this arrangement remains unclear. Three main models of humidity transduction have been proposed. Hygroreceptors could operate as mechanical hygrometers, psychrometers or evaporation detectors. Each mode of action measures a different humidity parameter. Mechanical hygrometers measure the relative humidity, psychrometers indicate the wet-bulb temperature, and evaporimeters refer to the saturation deficit of the air. Here we assess the validity of the different functions by testing specific predictions drawn from each of the models. The effect of air temperature on the responses to humidity stimulation rules out the mechanical hygrometer function, but it supports the psychrometer function and highlights the action as evaporation rate detector. We suggest testing the effect of the flow rate of the air stream used for humidity stimulation. As the wind speed strongly affects the power of evaporation, experiments with changing saturation deficit at different flow rates would improve our knowledge on humidity transduction.

Nitric oxide-sphingolipid interplays in plant signalling: a new enigma from the Sphinx?

PubMed

Guillas, Isabelle; Puyaubert, Juliette; Baudouin, Emmanuel

2013-09-12

Nitric oxide (NO) emerged as one of the major signaling molecules operating during plant development and plant responses to its environment. Beyond the identification of the direct molecular targets of NO, a series of studies considered its interplay with other actors of signal transduction and the integration of NO into complex signaling networks. Beside the close relationships between NO and calcium or phosphatidic acid signaling pathways that are now well-established, recent reports paved the way for interplays between NO and sphingolipids (SLs). This mini-review summarizes our current knowledge of the influence NO and SLs might exert on each other in plant physiology. Based on comparisons with examples from the animal field, it further indicates that, although SL-NO interplays are common features in signaling networks of eukaryotic cells, the underlying mechanisms and molecular targets significantly differ.

Regulation and Role of Fungal Secondary Metabolites.

PubMed

Macheleidt, Juliane; Mattern, Derek J; Fischer, Juliane; Netzker, Tina; Weber, Jakob; Schroeckh, Volker; Valiante, Vito; Brakhage, Axel A

2016-11-23

Fungi have the capability to produce a tremendous number of so-called secondary metabolites, which possess a multitude of functions, e.g., communication signals during coexistence with other microorganisms, virulence factors during pathogenic interactions with plants and animals, and in medical applications. Therefore, research on this topic has intensified significantly during the past 10 years and thus knowledge of regulatory mechanisms and the understanding of the role of secondary metabolites have drastically increased. This review aims to depict the complexity of all the regulatory elements involved in controlling the expression of secondary metabolite gene clusters, ranging from epigenetic control and signal transduction pathways to global and specific transcriptional regulators. Furthermore, we give a short overview on the role of secondary metabolites, focusing on the interaction with other microorganisms in the environment as well as on pathogenic relationships.

Biophysical and biochemical constraints imposed by salt stress: learning from halophytes

PubMed Central

Duarte, Bernardo; Sleimi, Noomene; Caçador, Isabel

2014-01-01

Soil salinization is one of the most important factors impacting plant productivity. About 3.6 billion of the world’s 5.2 billion ha of agricultural dry land, have already suffered erosion, degradation, and salinization. Halophytes are typically considered as plants able to complete their life cycle in environments where the salt concentration is above 200 mM NaCl. Salinity adjustment is a complex phenomenon but essential mechanism to overcome salt stress, with both biophysical and biochemical implications. At this level, halophytes evolved in several directions, adopting different strategies. Otherwise, the lack of adaptation to a salt environment would negatively affect their electron transduction pathways and the entire energetic metabolism, the foundation of every plant photosynthesis and biomass production. The maintenance of ionic homeostasis is in the basis of all cellular counteractive measures, in particular in terms of redox potential and energy transduction. In the present work the biophysical mechanisms underlying energy capture and transduction in halophytes are discussed alongside with their relation with biochemical counteractive mechanisms, integrating data from photosynthetic light harvesting complexes, electron transport chains to the quinone pools, carbon fixation, and energy dissipation metabolism. PMID:25566311

Revisiting Theories of Humidity Transduction: A Focus on Electrophysiological Data

PubMed Central

Tichy, Harald; Hellwig, Maria; Kallina, Wolfgang

2017-01-01

Understanding the mechanism of humidity transduction calls for experimental data and a theory to interpret the data and design new experiments. A comprehensive theory of humidity transduction must start with agreement on what humidity parameters are measured by hygroreceptors and processed by the brain. Hygroreceptors have been found in cuticular sensilla of a broad range of insect species. Their structural features are far from uniform. Nevertheless, these sensilla always contain an antagonistic pair of a moist cell and a dry cell combined with a thermoreceptive cold cell. The strategy behind this arrangement remains unclear. Three main models of humidity transduction have been proposed. Hygroreceptors could operate as mechanical hygrometers, psychrometers or evaporation detectors. Each mode of action measures a different humidity parameter. Mechanical hygrometers measure the relative humidity, psychrometers indicate the wet-bulb temperature, and evaporimeters refer to the saturation deficit of the air. Here we assess the validity of the different functions by testing specific predictions drawn from each of the models. The effect of air temperature on the responses to humidity stimulation rules out the mechanical hygrometer function, but it supports the psychrometer function and highlights the action as evaporation rate detector. We suggest testing the effect of the flow rate of the air stream used for humidity stimulation. As the wind speed strongly affects the power of evaporation, experiments with changing saturation deficit at different flow rates would improve our knowledge on humidity transduction. PMID:28928673

Discrete dynamic modeling of cellular signaling networks.

PubMed

Albert, Réka; Wang, Rui-Sheng

2009-01-01

Understanding signal transduction in cellular systems is a central issue in systems biology. Numerous experiments from different laboratories generate an abundance of individual components and causal interactions mediating environmental and developmental signals. However, for many signal transduction systems there is insufficient information on the overall structure and the molecular mechanisms involved in the signaling network. Moreover, lack of kinetic and temporal information makes it difficult to construct quantitative models of signal transduction pathways. Discrete dynamic modeling, combined with network analysis, provides an effective way to integrate fragmentary knowledge of regulatory interactions into a predictive mathematical model which is able to describe the time evolution of the system without the requirement for kinetic parameters. This chapter introduces the fundamental concepts of discrete dynamic modeling, particularly focusing on Boolean dynamic models. We describe this method step-by-step in the context of cellular signaling networks. Several variants of Boolean dynamic models including threshold Boolean networks and piecewise linear systems are also covered, followed by two examples of successful application of discrete dynamic modeling in cell biology.

Genome, Integration, and Transduction of a Novel Temperate Phage of Helicobacter pylori

PubMed Central

Luo, Cheng-Hung; Chiou, Pei-Yu; Yang, Chiou-Ying

2012-01-01

Helicobacter pylori is a common human pathogen that has been identified to be carcinogenic. This study isolated the temperate bacteriophage 1961P from the lysate of a clinical strain of H. pylori isolated in Taiwan. The bacteriophage has an icosahedral head and a short tail, typical of the Podoviridae family. Its double-stranded DNA genome is 26,836 bp long and has 33 open reading frames. Only 9 of the predicted proteins have homologs of known functions, while the remaining 24 are only similar to unknown proteins encoded by Helicobacter prophages and remnants. Analysis of sequences proximal to the phage-host junctions suggests that 1961P may integrate into the host chromosome via a mechanism similar to that of bacteriophage lambda. In addition, 1961P is capable of generalized transduction. To the best of our knowledge, this is the first report of the isolation, characterization, genome analysis, integration, and transduction of a Helicobacter pylori phage. PMID:22696647

Nitric oxide-sphingolipid interplays in plant signalling: a new enigma from the Sphinx?

PubMed Central

Guillas, Isabelle; Puyaubert, Juliette; Baudouin, Emmanuel

2013-01-01

Nitric oxide (NO) emerged as one of the major signaling molecules operating during plant development and plant responses to its environment. Beyond the identification of the direct molecular targets of NO, a series of studies considered its interplay with other actors of signal transduction and the integration of NO into complex signaling networks. Beside the close relationships between NO and calcium or phosphatidic acid signaling pathways that are now well-established, recent reports paved the way for interplays between NO and sphingolipids (SLs). This mini-review summarizes our current knowledge of the influence NO and SLs might exert on each other in plant physiology. Based on comparisons with examples from the animal field, it further indicates that, although SL–NO interplays are common features in signaling networks of eukaryotic cells, the underlying mechanisms and molecular targets significantly differ. PMID:24062754

Novel Insights on Thyroid-Stimulating Hormone Receptor Signal Transduction

PubMed Central

Neumann, Susanne; Grüters, Annette; Krude, Heiko

2013-01-01

The TSH receptor (TSHR) is a member of the glycoprotein hormone receptors, a subfamily of family A G protein-coupled receptors. The TSHR is of great importance for the growth and function of the thyroid gland. The TSHR and its endogenous ligand TSH are pivotal proteins with respect to a variety of physiological functions and malfunctions. The molecular events of TSHR regulation can be summarized as a process of signal transduction, including signal reception, conversion, and amplification. The steps during signal transduction from the extra- to the intracellular sites of the cell are not yet comprehensively understood. However, essential new insights have been achieved in recent years on the interrelated mechanisms at the extracellular region, the transmembrane domain, and intracellular components. This review contains a critical summary of available knowledge of the molecular mechanisms of signal transduction at the TSHR, for example, the key amino acids involved in hormone binding or in the structural conformational changes that lead to G protein activation or signaling regulation. Aspects of TSHR oligomerization, signaling promiscuity, signaling selectivity, phenotypes of genetic variations, and potential extrathyroidal receptor activity are also considered, because these are relevant to an understanding of the overall function of the TSHR, including physiological, pathophysiological, and pharmacological perspectives. Directions for future research are discussed. PMID:23645907

Signal Transduction Pathways of TNAP: Molecular Network Analyses.

PubMed

Négyessy, László; Györffy, Balázs; Hanics, János; Bányai, Mihály; Fonta, Caroline; Bazsó, Fülöp

2015-01-01

Despite the growing body of evidence pointing on the involvement of tissue non-specific alkaline phosphatase (TNAP) in brain function and diseases like epilepsy and Alzheimer's disease, our understanding about the role of TNAP in the regulation of neurotransmission is severely limited. The aim of our study was to integrate the fragmented knowledge into a comprehensive view regarding neuronal functions of TNAP using objective tools. As a model we used the signal transduction molecular network of a pyramidal neuron after complementing with TNAP related data and performed the analysis using graph theoretic tools. The analyses show that TNAP is in the crossroad of numerous pathways and therefore is one of the key players of the neuronal signal transduction network. Through many of its connections, most notably with molecules of the purinergic system, TNAP serves as a controller by funnelling signal flow towards a subset of molecules. TNAP also appears as the source of signal to be spread via interactions with molecules involved among others in neurodegeneration. Cluster analyses identified TNAP as part of the second messenger signalling cascade. However, TNAP also forms connections with other functional groups involved in neuronal signal transduction. The results indicate the distinct ways of involvement of TNAP in multiple neuronal functions and diseases.

Maxwell's demon in biochemical signal transduction with feedback loop

PubMed Central

Ito, Sosuke; Sagawa, Takahiro

2015-01-01

Signal transduction in living cells is vital to maintain life itself, where information transfer in noisy environment plays a significant role. In a rather different context, the recent intensive research on ‘Maxwell's demon'—a feedback controller that utilizes information of individual molecules—have led to a unified theory of information and thermodynamics. Here we combine these two streams of research, and show that the second law of thermodynamics with information reveals the fundamental limit of the robustness of signal transduction against environmental fluctuations. Especially, we find that the degree of robustness is quantitatively characterized by an informational quantity called transfer entropy. Our information-thermodynamic approach is applicable to biological communication inside cells, in which there is no explicit channel coding in contrast to artificial communication. Our result could open up a novel biophysical approach to understand information processing in living systems on the basis of the fundamental information–thermodynamics link. PMID:26099556

Polycyclic aromatic hydrocarbons - Primitive pigment systems in the prebiotic environment

NASA Technical Reports Server (NTRS)

Deamer, D. W.

1992-01-01

The chemical evolution of meteoritic organics in the primitive earth is examined experimentally with attention given to the photochemical effects of hydrocarbon/water mixtures. Also addressed are the generation of amphiphilic products by photochemical reactions and the transduction of light energy into potentially useful forms. Polycyclic aromatic hydrocarbons (PAHs) absorb light and exist in carbonaceous chondrites; PAHs are therefore examined as primitive pigments by means of salt solutions with pyrene, fluoranthene, and pyrene derivatives with hexadecane. The hexadecane undergoes photochemical oxidation and yields long-chain amphiphiles with oxygen supplied by water, and acid pH shifts also occur. PAHs are also tested in lipid bilayer membranes to examine light-energy transduction. Protons are found to accumulate within the membrane-bounded volume to form proton gradients, and this reaction is theorized to be a good model of primitive photochemical reactions that related to the transduction of light energy into useable forms.

Phenomenally High Transduction Air/gas Transducers for Practical Non-Contact Ultrasonic Applications

NASA Astrophysics Data System (ADS)

Bhardwaj, Mahesh C.

2009-03-01

Based on novel acoustic impedance matching layers and high coupling piezoelectric materials this paper describes exceptionally high air/gas transduction ultrasonic transducers. By providing applications oriented performance of these transducers we also usher in the era of much desired Non-Contact Ultrasound (NCU) testing and analysis of a wide range of materials including early stage formation of materials such as uncured composite prepregs, green ceramics and powder metals, plastics, elastomers, porous, hygroscopic, chemically bonded and other materials. Besides quality control, ultimately NCU offers timely opportunities for cost-effective materials production, energy savings, and environment protection.

Jasmonate-mediated stomatal closure under elevated CO2 revealed by time-resolved metabolomics

USDA-ARS?s Scientific Manuscript database

Foliar stomatal movements are critical for regulating plant water status and gas exchange. Elevated carbon dioxide (CO2) concentrations are known to induce stomatal closure. However, current knowledge on CO2 signal transduction in stomatal guard cells is limited. Here we report the metabolomic respo...

Membrane guanylate cyclase, a multimodal transduction machine: history, present, and future directions

PubMed Central

Sharma, Rameshwar K.; Duda, Teresa

2014-01-01

A sequel to these authors' earlier comprehensive reviews which covered the field of mammalian membrane guanylate cyclase (MGC) from its origin to the year 2010, this article contains 13 sections. The first is historical and covers MGC from the year 1963–1987, summarizing its colorful developmental stages from its passionate pursuit to its consolidation. The second deals with the establishment of its biochemical identity. MGC becomes the transducer of a hormonal signal and founder of the peptide hormone receptor family, and creates the notion that hormone signal transduction is its sole physiological function. The third defines its expansion. The discovery of ROS-GC subfamily is made and it links ROS-GC with the physiology of phototransduction. Sections ROS-GC, a Ca2+-Modulated Two Component Transduction System to Migration Patterns and Translations of the GCAP Signals Into Production of Cyclic GMP are Different cover its biochemistry and physiology. The noteworthy events are that augmented by GCAPs, ROS-GC proves to be a transducer of the free Ca2+ signals generated within neurons; ROS-GC becomes a two-component transduction system and establishes itself as a source of cyclic GMP, the second messenger of phototransduction. Section ROS-GC1 Gene Linked Retinal Dystrophies demonstrates how this knowledge begins to be translated into the diagnosis and providing the molecular definition of retinal dystrophies. Section Controlled By Low and High Levels of [Ca2+]i, ROS-GC1 is a Bimodal Transduction Switch discusses a striking property of ROS-GC where it becomes a “[Ca2+]i bimodal switch” and transcends its signaling role in other neural processes. In this course, discovery of the first CD-GCAP (Ca2+-dependent guanylate cyclase activator), the S100B protein, is made. It extends the role of the ROS-GC transduction system beyond the phototransduction to the signaling processes in the synapse region between photoreceptor and cone ON-bipolar cells; in section Ca2+-Modulated Neurocalcin δ ROS-GC1 Transduction System Exists in the Inner Plexiform Layer (IPL) of the Retinal Neurons, discovery of another CD-GCAP, NCδ, is made and its linkage with signaling of the inner plexiform layer neurons is established. Section ROS-GC Linkage With Other Than Vision-Linked Neurons discusses linkage of the ROS-GC transduction system with other sensory transduction processes: Pineal gland, Olfaction and Gustation. In the next, section Evolution of a General Ca2+-Interlocked ROS-GC Signal Transduction Concept in Sensory and Sensory-Linked Neurons, a theoretical concept is proposed where “Ca2+-interlocked ROS-GC signal transduction” machinery becomes a common signaling component of the sensory and sensory-linked neurons. Closure to the review is brought by the conclusion and future directions. PMID:25071437

The COPD Knowledge Base: enabling data analysis and computational simulation in translational COPD research.

PubMed

Cano, Isaac; Tényi, Ákos; Schueller, Christine; Wolff, Martin; Huertas Migueláñez, M Mercedes; Gomez-Cabrero, David; Antczak, Philipp; Roca, Josep; Cascante, Marta; Falciani, Francesco; Maier, Dieter

2014-11-28

Previously we generated a chronic obstructive pulmonary disease (COPD) specific knowledge base (http://www.copdknowledgebase.eu) from clinical and experimental data, text-mining results and public databases. This knowledge base allowed the retrieval of specific molecular networks together with integrated clinical and experimental data. The COPDKB has now been extended to integrate over 40 public data sources on functional interaction (e.g. signal transduction, transcriptional regulation, protein-protein interaction, gene-disease association). In addition we integrated COPD-specific expression and co-morbidity networks connecting over 6 000 genes/proteins with physiological parameters and disease states. Three mathematical models describing different aspects of systemic effects of COPD were connected to clinical and experimental data. We have completely redesigned the technical architecture of the user interface and now provide html and web browser-based access and form-based searches. A network search enables the use of interconnecting information and the generation of disease-specific sub-networks from general knowledge. Integration with the Synergy-COPD Simulation Environment enables multi-scale integrated simulation of individual computational models while integration with a Clinical Decision Support System allows delivery into clinical practice. The COPD Knowledge Base is the only publicly available knowledge resource dedicated to COPD and combining genetic information with molecular, physiological and clinical data as well as mathematical modelling. Its integrated analysis functions provide overviews about clinical trends and connections while its semantically mapped content enables complex analysis approaches. We plan to further extend the COPDKB by offering it as a repository to publish and semantically integrate data from relevant clinical trials. The COPDKB is freely available after registration at http://www.copdknowledgebase.eu.

From the outside, from within: Biological and therapeutic relevance of signal transduction in T-cell acute lymphoblastic leukemia.

PubMed

Oliveira, Mariana L; Akkapeddi, Padma; Alcobia, Isabel; Almeida, Afonso R; Cardoso, Bruno A; Fragoso, Rita; Serafim, Teresa L; Barata, João T

2017-10-01

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological cancer that arises from clonal expansion of transformed T-cell precursors. In this review we summarize the current knowledge on the external stimuli and cell-intrinsic lesions that drive aberrant activation of pivotal, pro-tumoral intracellular signaling pathways in T-cell precursors, driving transformation, leukemia expansion, spread or resistance to therapy. In addition to their pathophysiological relevance, receptors and kinases involved in signal transduction are often attractive candidates for targeted drug development. As such, we discuss also the potential of T-ALL signaling players as targets for therapeutic intervention. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Structural insight into partner specificity and phosphoryl transfer in two-component signal transduction.

PubMed

Casino, Patricia; Rubio, Vicente; Marina, Alberto

2009-10-16

The chief mechanism used by bacteria for sensing their environment is based on two conserved proteins: a sensor histidine kinase (HK) and an effector response regulator (RR). The signal transduction process involves highly conserved domains of both proteins that mediate autokinase, phosphotransfer, and phosphatase activities whose output is a finely tuned RR phosphorylation level. Here, we report the structure of the complex between the entire cytoplasmic portion of Thermotoga maritima class I HK853 and its cognate, RR468, as well as the structure of the isolated RR468, both free and BeF(3)(-) bound. Our results provide insight into partner specificity in two-component systems, recognition of the phosphorylation state of each partner, and the catalytic mechanism of the phosphatase reaction. Biochemical analysis shows that the HK853-catalyzed autokinase reaction proceeds by a cis autophosphorylation mechanism within the HK subunit. The results suggest a model for the signal transduction mechanism in two-component systems.

Dynamic Receptor Team Formation Can Explain the High Signal Transduction Gain in Escherichia coli

NASA Astrophysics Data System (ADS)

Albert, R.; Chiu, Y.; Othmer, H.

2004-05-01

Evolution has provided many organisms with sophisticated sensory systems that enable them to respond to signals in their environment. The response frequently involves alteration in the pattern of movement, such as the chemokinesis of the bacterium Escherichia coli, which swims by rotating its flagella. When rotated counterclockwise (CCW) the flagella coalesce into a propulsive bundle, producing a relatively straight ``run'', and when rotated clockwise (CW) they fly apart, resulting in a ``tumble'' which reorients the cell with little translocation. A stochastic process generates the runs and tumbles, and in a chemoeffector gradient runs that carry the cell in a favorable direction are extended. The overall structure of the signal transduction pathways is well-characterized in E. coli, but important details are still not understood. Only recently has a source of gain in the signal transduction network been identified experimentally, and here we present a mathematical model based on dynamic assembly of receptor teams that can explain this observation.

Bcl-2 silencing attenuates hypoxia-induced apoptosis resistance in pulmonary microvascular endothelial cells.

PubMed

Cao, Yongmei; Jiang, Zhen; Zeng, Zhen; Liu, Yujing; Gu, Yuchun; Ji, Yingying; Zhao, Yupeng; Li, Yingchuan

2016-01-01

Pulmonary arterial hypertension (PAH) is a life-threatening disorder that ultimately causes heart failure. While the underlying causes of this condition are not well understood, previous studies suggest that the anti-apoptotic nature of pulmonary microvascular endothelial cells (PMVECs) in hypoxic environments contributes to PAH pathogenesis. In this study, we focus on the contribution of Bcl-2 and hypoxia response element (HRE) to apoptosis-resistant endothelial cells and investigate the mechanism. PMVECs obtained from either normal rats or apoptosis-resistant PMVECs obtained from PAH rats were transduced with recombinant lentiviral vectors carrying either Bcl-2-shRNA or HRE combined Bcl-2-shRNA, and then cultured these cells for 24 h under hypoxic (5% O2) or normoxic (21% O2) conditions. In normal PMVECs, Bcl-2-shRNA or HRE combined with Bcl-2-shRNA transduction successfully decreased Bcl-2 expression, while increasing apoptosis as well as caspase-3 and P53 expression in a normoxic environment. In a hypoxic environment, the effects of Bcl-2-shRNA treatment on cell apoptosis, and on Bcl-2, caspase-3, P53 expression were significantly suppressed. Conversely, HRE activation combined with Bcl-2-shRNA transduction markedly enhanced cell apoptosis and upregulated caspase-3 and P53 expression, while decreasing Bcl-2 expression. Furthermore, in apoptosis-resistant PMVECs, HRE-mediated Bcl-2 silencing effectively enhanced cell apoptosis and caspase-3 activity. The apoptosis rate was significantly depressed when Lv-HRE-Bcl-2-shRNA was combined with Lv-P53-shRNA or Lv-caspase3-shRNA transduction in a hypoxic environment. These results suggest that HRE-mediated Bcl-2 inhibition can effectively attenuate hypoxia-induced apoptosis resistance in PMVECs by downregulating Bcl-2 expression and upregulating caspase-3 and P53 expression. This study therefore reveals critical insight into potential therapeutic targets for treating PAH.

Expansion of signal transduction pathways in fungi by extensive genome duplication

PubMed Central

Corrochano, Luis M.; Kuo, Alan; Marcet-Houben, Marina; Polaino, Silvia; Salamov, Asaf; Villalobos-Escobedo, José M.; Grimwood, Jane; Álvarez, M. Isabel; Avalos, Javier; Bauer, Diane; Benito, Ernesto P.; Benoit, Isabelle; Burger, Gertraud; Camino, Lola P.; Cánovas, David; Cerdá-Olmedo, Enrique; Cheng, Jan-Fang; Domínguez, Angel; Eliáš, Marek; Eslava, Arturo P.; Glaser, Fabian; Gutiérrez, Gabriel; Heitman, Joseph; Henrissat, Bernard; Iturriaga, Enrique A.; Lang, B. Franz; Lavín, José L.; Lee, Soo Chan; Li, Wenjun; Lindquist, Erika; López-García, Sergio; Luque, Eva M.; Marcos, Ana T.; Martin, Joel; McCluskey, Kevin; Medina, Humberto R.; Miralles-Durán, Alejandro; Miyazaki, Atsushi; Muñoz-Torres, Elisa; Oguiza, José A.; Ohm, Robin A.; Orejas, Margarita; Ortiz-Castellanos, Lucila; Pisabarro, Antonio G.; Rodríguez-Romero, Julio; Ruiz-Herrera, José; Ruiz-Vázquez, Rosa; Sanz, Catalina; Schackwitz, Wendy; Shahriari, Mahdi; Shelest, Ekaterina; Silva-Franco, Fátima; Soanes, Darren; Syed, Khajamohiddin; Tagua, Víctor G.; Talbot, Nicholas J.; Thon, Michael R.; Tice, Hope; de Vries, Ronald P.; Wiebenga, Ad; Yadav, Jagjit S.; Braun, Edward L.; Baker, Scott E.; Garre, Victoriano; Schmutz, Jeremy; Horwitz, Benjamin A.; Torres-Martínez, Santiago; Idnurm, Alexander; Herrera-Estrella, Alfredo; Gabaldón, Toni; Grigoriev, Igor V.

2016-01-01

Summary Plants and fungi use light and other signals to regulate development, growth, and metabolism. The fruiting bodies of the fungus Phycomyces blakesleeanus are single cells that react to environmental cues, including light, but the mechanisms are largely unknown [1]. The related fungus Mucor circinelloides is an opportunistic human pathogen that changes its mode of growth upon receipt of signals from the environment to facilitate pathogenesis [2]. Understanding how these organisms respond to environmental cues should provide insights into the mechanisms of sensory perception and signal transduction by a single eukaryotic cell, and their role in pathogenesis. We sequenced the genomes of P. blakesleeanus and M. circinelloides, and show that they have been shaped by an extensive genome duplication or, most likely, a whole genome duplication (WGD), which is rarely observed in fungi [3-6]. We show that the genome duplication has expanded gene families, including those involved in signal transduction, and that duplicated genes have specialized, as evidenced by differences in their regulation by light. The transcriptional response to light varies with the developmental stage and is still observed in a photoreceptor mutant of P. blakesleeanus. A phototropic mutant of P. blakesleeanus with a heterozygous mutation in the photoreceptor gene madA demonstrates that photosensor dosage is important for the magnitude of signal transduction. We conclude that the genome duplication provided the means to improve signal transduction for enhanced perception of environmental signals. Our results will help to understand the role of genome dynamics in the evolution of sensory perception in eukaryotes. PMID:27238284

In-cell thermodynamics and a new role for protein surfaces.

PubMed

Smith, Austin E; Zhou, Larry Z; Gorensek, Annelise H; Senske, Michael; Pielak, Gary J

2016-02-16

There is abundant, physiologically relevant knowledge about protein cores; they are hydrophobic, exquisitely well packed, and nearly all hydrogen bonds are satisfied. An equivalent understanding of protein surfaces has remained elusive because proteins are almost exclusively studied in vitro in simple aqueous solutions. Here, we establish the essential physiological roles played by protein surfaces by measuring the equilibrium thermodynamics and kinetics of protein folding in the complex environment of living Escherichia coli cells, and under physiologically relevant in vitro conditions. Fluorine NMR data on the 7-kDa globular N-terminal SH3 domain of Drosophila signal transduction protein drk (SH3) show that charge-charge interactions are fundamental to protein stability and folding kinetics in cells. Our results contradict predictions from accepted theories of macromolecular crowding and show that cosolutes commonly used to mimic the cellular interior do not yield physiologically relevant information. As such, we provide the foundation for a complete picture of protein chemistry in cells.

Application of Petri net based analysis techniques to signal transduction pathways.

PubMed

Sackmann, Andrea; Heiner, Monika; Koch, Ina

2006-11-02

Signal transduction pathways are usually modelled using classical quantitative methods, which are based on ordinary differential equations (ODEs). However, some difficulties are inherent in this approach. On the one hand, the kinetic parameters involved are often unknown and have to be estimated. With increasing size and complexity of signal transduction pathways, the estimation of missing kinetic data is not possible. On the other hand, ODEs based models do not support any explicit insights into possible (signal-) flows within the network. Moreover, a huge amount of qualitative data is available due to high-throughput techniques. In order to get information on the systems behaviour, qualitative analysis techniques have been developed. Applications of the known qualitative analysis methods concern mainly metabolic networks. Petri net theory provides a variety of established analysis techniques, which are also applicable to signal transduction models. In this context special properties have to be considered and new dedicated techniques have to be designed. We apply Petri net theory to model and analyse signal transduction pathways first qualitatively before continuing with quantitative analyses. This paper demonstrates how to build systematically a discrete model, which reflects provably the qualitative biological behaviour without any knowledge of kinetic parameters. The mating pheromone response pathway in Saccharomyces cerevisiae serves as case study. We propose an approach for model validation of signal transduction pathways based on the network structure only. For this purpose, we introduce the new notion of feasible t-invariants, which represent minimal self-contained subnets being active under a given input situation. Each of these subnets stands for a signal flow in the system. We define maximal common transition sets (MCT-sets), which can be used for t-invariant examination and net decomposition into smallest biologically meaningful functional units. The paper demonstrates how Petri net analysis techniques can promote a deeper understanding of signal transduction pathways. The new concepts of feasible t-invariants and MCT-sets have been proven to be useful for model validation and the interpretation of the biological system behaviour. Whereas MCT-sets provide a decomposition of the net into disjunctive subnets, feasible t-invariants describe subnets, which generally overlap. This work contributes to qualitative modelling and to the analysis of large biological networks by their fully automatic decomposition into biologically meaningful modules.

Application of Petri net based analysis techniques to signal transduction pathways

PubMed Central

Sackmann, Andrea; Heiner, Monika; Koch, Ina

2006-01-01

Background Signal transduction pathways are usually modelled using classical quantitative methods, which are based on ordinary differential equations (ODEs). However, some difficulties are inherent in this approach. On the one hand, the kinetic parameters involved are often unknown and have to be estimated. With increasing size and complexity of signal transduction pathways, the estimation of missing kinetic data is not possible. On the other hand, ODEs based models do not support any explicit insights into possible (signal-) flows within the network. Moreover, a huge amount of qualitative data is available due to high-throughput techniques. In order to get information on the systems behaviour, qualitative analysis techniques have been developed. Applications of the known qualitative analysis methods concern mainly metabolic networks. Petri net theory provides a variety of established analysis techniques, which are also applicable to signal transduction models. In this context special properties have to be considered and new dedicated techniques have to be designed. Methods We apply Petri net theory to model and analyse signal transduction pathways first qualitatively before continuing with quantitative analyses. This paper demonstrates how to build systematically a discrete model, which reflects provably the qualitative biological behaviour without any knowledge of kinetic parameters. The mating pheromone response pathway in Saccharomyces cerevisiae serves as case study. Results We propose an approach for model validation of signal transduction pathways based on the network structure only. For this purpose, we introduce the new notion of feasible t-invariants, which represent minimal self-contained subnets being active under a given input situation. Each of these subnets stands for a signal flow in the system. We define maximal common transition sets (MCT-sets), which can be used for t-invariant examination and net decomposition into smallest biologically meaningful functional units. Conclusion The paper demonstrates how Petri net analysis techniques can promote a deeper understanding of signal transduction pathways. The new concepts of feasible t-invariants and MCT-sets have been proven to be useful for model validation and the interpretation of the biological system behaviour. Whereas MCT-sets provide a decomposition of the net into disjunctive subnets, feasible t-invariants describe subnets, which generally overlap. This work contributes to qualitative modelling and to the analysis of large biological networks by their fully automatic decomposition into biologically meaningful modules. PMID:17081284

[From free radicals to science of nutrition].

PubMed

Blázovics, Anna

2009-01-11

During the decades of free radical research, we came ever closer to the knowledge that the free radical-antioxidant balance of the organs is modified fundamentally by the genetic background and surroundings. Janus-face oxygen free radicals are the secondary messengers of signal transduction routes and simultaneously they are cytotoxic agents of cells. The activation of signal transduction proteins by moderate oxidation effects and metal ions is not fairly known yet. The molecular mechanism between activators and inhibitors of signal transduction is controlled in a fine way. The balance of antioxidant-prooxidant levels of the cells can go back to the concentration relation of sulfhydril groups and disulfid bridges. Essential and toxic metal ions and selenium can play an important role in the redox homeostasis. Healthy tissues have many antioxidants, hereby they ensure the protection of the organs against free radicals. Alimentary antioxidants such as vitamin A, C and E, polyphenols, anthocyanins, flavonoids, isothiocyanates and other bioactive molecules in their natural molecular structure and derivates are able to influence the redox reactions. In our days more and more molecules from foods, or their metabolites are verified to act on genes based on the results of molecular biological research.

High hydrostatic pressure induces ERK and PI3 kinase phosphorylation in human HCS-2/8 chondrosarcoma cells.

PubMed

Kopakkala-Tani, M; Elo, M A; Sironen, R K; Helminen, H J; Lammi, M J

2004-06-01

High continuous hydrostatic pressure has been shown to affect many cellular functions within the pressurised cells, for instance, accumulation of heat shock protein 70 occurs during pressurisation. Various signal transduction pathways are likely to mediate these changes, however, at the present time our knowledge of the pathways involved is rather limited. The aim of this study was to investigate whether some of the well known transduction pathways are activated by the exposure of human chondrosarcoma cells to 15-30 MPa hydrostatic pressure. The results showed an increased presence of the active, phosphorylated forms of extracellular signal-related kinase (ERK) and phosphoinositide 3-kinase (PI3K) in cells exposed to 15 and 30 MPa continuous hydrostatic pressure, while 0.5 Hz cyclic loading had weaker effects. Inhibition of ERK-pathway with UO126 did not prevent the accumulation of heat shock protein 70. No activation of c-Jun N-terminal protein kinase (JNK) or p38 could be noticed in pressurised cells. In conclusion, we could identify at least two different signal transduction pathways that are activated under high continuous hydrostatic pressure. Accumulation of heat shock protein 70 was independent of ERK-activation.

Neurally and Ocularly Informed Graph-Based Models for Searching 3D Environments

DTIC Science & Technology

2014-06-03

hBCI = hybrid brain–computer interface, TAG = transductive annotation by graph, CV = computer vision, TSP = traveling salesman problem . are navigated...environment that are most likely to contain objects that the subject would like to visit. 2.9. Route planning A traveling salesman problem (TSP) solver...fixations in a visual search task using fixation-related potentials J. Vis. 13 Croes G 1958 A method for solving traveling - salesman problems Oper. Res

Nucleotide Signaling and Cutaneous Mechanisms of Pain Transduction

PubMed Central

Dussor, G.; Koerber, H.R.; Oaklander, AL; Rice, F.L.; Molliver, D.C.

2009-01-01

Sensory neurons that innervate the skin provide critical information about physical contact between the organism and the environment, including information about potentially-damaging stimuli that give rise to the sensation of pain. These afferents also contribute to the maintenance of tissue homeostasis, inflammation and wound healing, while sensitization of sensory afferents after injury results in painful hypersensitivity and protective behavior. In contrast to the traditional view of primary afferent terminals as the sole site of sensory transduction, recent reports have lead to the intriguing idea that cells of the skin play an active role in the transduction of sensory stimuli. The search for molecules that transduce different types of sensory stimuli (mechanical, heat, chemical) at the axon terminal has yielded a wide range of potential effectors, many of which are expressed by keratinocytes as well as neurons. Emerging evidence underscores the importance of nucleotide signaling through P2X ionotropic and P2Y metabotropic receptors in pain processing, and implicates nucleotide signaling as a critical form of communication between cells of the skin, immune cells and sensory neurons. It is of great interest to determine whether pathological changes in these mechanisms contribute to chronic pain in human disease states such as complex regional pain syndrome (CRPS). This review discusses recent advances in our understanding of communication mechanisms between cells of the skin and sensory axons in the transduction of sensory input leading to pain. PMID:19171165

Complex Structure and Biochemical Characterization of the Staphylococcus aureus Cyclic Diadenylate Monophosphate (c-di-AMP)-binding Protein PstA, the Founding Member of a New Signal Transduction Protein Family*

PubMed Central

Campeotto, Ivan; Zhang, Yong; Mladenov, Miroslav G.; Freemont, Paul S.; Gründling, Angelika

2015-01-01

Signaling nucleotides are integral parts of signal transduction systems allowing bacteria to cope with and rapidly respond to changes in the environment. The Staphylococcus aureus PII-like signal transduction protein PstA was recently identified as a cyclic diadenylate monophosphate (c-di-AMP)-binding protein. Here, we present the crystal structures of the apo- and c-di-AMP-bound PstA protein, which is trimeric in solution as well as in the crystals. The structures combined with detailed bioinformatics analysis revealed that the protein belongs to a new family of proteins with a similar core fold but with distinct features to classical PII proteins, which usually function in nitrogen metabolism pathways in bacteria. The complex structure revealed three identical c-di-AMP-binding sites per trimer with each binding site at a monomer-monomer interface. Although distinctly different from other cyclic-di-nucleotide-binding sites, as the half-binding sites are not symmetrical, the complex structure also highlighted common features for c-di-AMP-binding sites. A comparison between the apo and complex structures revealed a series of conformational changes that result in the ordering of two anti-parallel β-strands that protrude from each monomer and allowed us to propose a mechanism on how the PstA protein functions as a signaling transduction protein. PMID:25505271

New Insight into the Role of Reactive Oxygen Species (ROS) in Cellular Signal-Transduction Processes.

PubMed

Russell, Eileen G; Cotter, Thomas G

2015-01-01

Reactive oxygen species (ROS) were once considered to be deleterious agents, contributing to a vast range of pathologies. But, now their protective effects are being appreciated. Both their damaging and beneficial effects are initiated when they target distinct molecules and consequently begin functioning as part of complex signal-transduction pathways. The recognition of ROS as signaling mediators has driven a wealth of research into their roles in both normal and pathophysiological states. The present review assesses the relevant recent literature to outline the current perspectives on redox-signaling mechanisms, physiological implications, and therapeutic strategies. This study highlights that a more fundamental knowledge about many aspects of redox signaling will allow better targeting of ROS, which would in turn improve prophylactic and pharmacotherapy for redox-associated diseases. Copyright © 2015 Elsevier Inc. All rights reserved.

Activity Dependent Signal Transduction in Skeletal Muscle

NASA Technical Reports Server (NTRS)

Hamilton, Susan L.

1999-01-01

The overall goals of this project are: 1) to define the initial signal transduction events whereby the removal of gravitational load from antigravity muscles, such as the soleus, triggers muscle atrophy, and 2) to develop countermeasures to prevent this from happening. Our rationale for this approach is that, if countermeasures can be developed to regulate these early events, we could avoid having to deal with the multiple cascades of events that occur downstream from the initial event. One of our major findings is that hind limb suspension causes an early and sustained increase in intracellular Ca(2+) concentration ([Ca (2+)](sub i)). In most cells the consequences of changes in ([Ca (2+)](sub i))depend on the amplitude, frequency and duration of the Ca(2+) signal and on other factors in the intracellular environment. We propose that muscle remodeling in microgravity represents a change in the balance among several CA(2+) regulated signal transduction pathways, in particular those involving the transcription factors NFAT and NFkB and the pro-apoptotic protein BAD. Other Ca(2+) sensitive pathways involving PKC, ras, rac, and CaM kinase II may also contribute to muscle remodeling.

IMPORTANCE OF THE DYNAMICS OF BACTERIOPHAGE-HOST INTERACTIONS TO BACTERIAL ABUNDANCE AND GENETIC DIVERSITY IN AQUATIC ENVIRONMENTS (RESEARCH BRIEF)

EPA Science Inventory

Using Pseudomonas aeruginosa and its bacteriophages as a model system, we have clearly demonstrated a significant potential for viral-mediated gene transfer (transduction) of both plasmid and chromosomal DNA in freshwater microbial populations. These investigations have predicted...

Ninth International Workshop on Plant Membrane Biology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1993-12-31

This report is a compilation of abstracts from papers which were discussed at a workshop on plant membrane biology. Topics include: plasma membrane ATP-ases; plant-environment interactions, membrane receptors; signal transduction; ion channel physiology; biophysics and molecular biology; vaculor H+ pumps; sugar carriers; membrane transport; and cellular structure and function.

Comparison of Electrochemical Immunosensors and Aptasensors for Detection of Small Organic Molecules in Environment, Food Safety, Clinical and Public Security.

PubMed

Piro, Benoit; Shi, Shihui; Reisberg, Steeve; Noël, Vincent; Anquetin, Guillaume

2016-02-29

We review here the most frequently reported targets among the electrochemical immunosensors and aptasensors: antibiotics, bisphenol A, cocaine, ochratoxin A and estradiol. In each case, the immobilization procedures are described as well as the transduction schemes and the limits of detection. It is shown that limits of detections are generally two to three orders of magnitude lower for immunosensors than for aptasensors, due to the highest affinities of antibodies. No significant progresses have been made to improve these affinities, but transduction schemes were improved instead, which lead to a regular improvement of the limit of detections corresponding to ca. five orders of magnitude over these last 10 years. These progresses depend on the target, however.

Identification and comparative expression analysis of interleukin 2/15 receptor B chain in chickens infected with E. tenella

USDA-ARS?s Scientific Manuscript database

Background: Interleukin (IL) 2 and IL15 receptor beta chain (IL2/15Receptor beta, CD122) play critical roles in signal transduction for the biological activities of IL2 and IL15. Increased knowledge of non-mammalian IL2/15Receptor beta will enhance the understanding of IL2 and IL15 functions. Meth...

The molecular circuitry of brassinosteroid signaling.

PubMed

Belkhadir, Youssef; Jaillais, Yvon

2015-04-01

Because they are tethered in space, plants have to make the most of their local growth environment. In order to grow in an ever-changing environment, plants constantly remodel their shapes. This adaptive attribute requires the orchestration of complex environmental signals at the cellular and organismal levels. A battery of small molecules, classically known as phytohormones, allows plants to change their body plan by using highly integrated signaling networks and transcriptional cascades. Amongst these hormones, brassinosteroids (BRs), the polyhydroxylated steroid of plants, influence plant responsiveness to the local environment and exquisitely promote, or interfere with, many aspects of plant development. The molecular circuits that wire steroid signals at the cell surface to the promoters of thousands of genes in the nucleus have been defined in the past decade. This review recapitulates how the transduction of BR signals impacts the temporally unfolding programs of plant growth. First, we summarize the paradigmatic BR signaling pathway acting primarily in cellular expansion. Secondly, we describe the current wiring diagram and the temporal dynamics of the BR signal transduction network. And finally we provide an overview of how key players in BR signaling act as molecular gates to transduce BR signals onto other signaling pathways. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

An energy balance concept for habitability.

PubMed

Hoehler, Tori M

2007-12-01

Habitability can be formulated as a balance between the biological demand for energy and the corresponding potential for meeting that demand by transduction of energy from the environment into biological process. The biological demand for energy is manifest in two requirements, analogous to the voltage and power requirements of an electrical device, which must both be met if life is to be supported. These requirements exhibit discrete (non-zero) minima whose magnitude is set by the biochemistry in question, and they are increased in quantifiable fashion by (i) deviations from biochemically optimal physical and chemical conditions and (ii) energy-expending solutions to problems of resource limitation. The possible rate of energy transduction is constrained by (i) the availability of usable free energy sources in the environment, (ii) limitations on transport of those sources into the cell, (iii) upper limits on the rate at which energy can be stored, transported, and subsequently liberated by biochemical mechanisms (e.g., enzyme saturation effects), and (iv) upper limits imposed by an inability to use "power" and "voltage" at levels that cause material breakdown. A system is habitable when the realized rate of energy transduction equals or exceeds the biological demand for energy. For systems in which water availability is considered a key aspect of habitability (e.g., Mars), the energy balance construct imposes additional, quantitative constraints that may help to prioritize targets in search-for-life missions. Because the biological need for energy is universal, the energy balance construct also helps to constrain habitability in systems (e.g., those envisioned to use solvents other than water) for which little constraint currently exists.

Cytosensor Microphysiometer: technology and recent applications.

PubMed

Hafner, F

2000-06-01

The Cytosensor Microphysiometer system detects functional responses from living cells in minutes and offers novel information on cell signalling that is often unobtainable with other assay methods. The principle of the system is based on the measurement of small changes in extracellular acidification, using a light addressable potentiometric sensor (LAPS). Energy metabolism in living cells is tightly coupled to cellular ATP usage, so that any event which perturbs cellular ATP levels--such as receptor activation and initiation of signal transduction--will result in a change in acid excretion. As the extrusion of protons is a very general parameter involved in the activation of nearly all kinds of membrane-bound receptors, receptors can be investigated without prior knowledge of the corresponding signalling pathway. However, by blocking certain signalling pathways inside the cell by means of signal transduction probes, specificity can be brought into the system and the corresponding receptor pathways can easily be elucidated. The aim is to give an overview about Cytosensor Microphysiometer technology and to demonstrate, with the help of some recent applications, the capability of the system to measure acidification rates from a wide variety of cell- and receptor-types coupled to different signal transduction pathways. This feature makes the cytosensor system an ideal tool for acting as a single assay system and circumventing the need for multiple assays.

Investigation of subcellular localization and dynamics of membrane proteins in living bacteria by combining optical micromanipulation and high-resolution microscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Barroso Peña, Álvaro; Nieves, Marcos; Teper, Konrad; Wedlich-Soldner, Roland; Denz, Cornelia

2016-09-01

The plasma membrane serves as protective interface between cells and their environment. It also constitutes a hub for selective nutrient uptake and signal transduction. Increasing evidence over the last years indicates that, similar to eukaryotic cells, lateral membrane organization plays an important role in the regulation of prokaryotic signaling pathways. However, the mechanisms underlying this phenomenon are still poorly understood. Spatiotemporal characterization of bacterial signal transduction demands very sensitive high-resolution microscopy techniques due to the low expression levels of most signaling proteins and the small size of bacterial cells. In addition, direct study of subcellular confinement and dynamics of bacterial signaling proteins during the different stages of the signal transduction also requires immobilization in order to avoid cell displacement caused by Brownian motion, local fluid flows and bacterial self-propulsion. In this work we present a novel approach based on the combination of high resolution imaging and optical manipulation that enables the investigation of the distribution and dynamics of proteins at the bacterial plasma membrane. For this purpose, we combine the versatility of holographic optical tweezers (HOT) with the sensitivity and resolution of total internal reflection fluorescence (TIRF) microscopy. Furthermore, we discuss the implementation of microfluidic devices in our integrated HOT+TIRF system for the control of growth conditions of bacterial cells. The capabilities of our workstation provides thus new valuable insights into the fundamental cellular and physical mechanisms underlying the regulation of bacterial signal transduction.

Comparison of Electrochemical Immunosensors and Aptasensors for Detection of Small Organic Molecules in Environment, Food Safety, Clinical and Public Security

PubMed Central

Piro, Benoit; Shi, Shihui; Reisberg, Steeve; Noël, Vincent; Anquetin, Guillaume

2016-01-01

We review here the most frequently reported targets among the electrochemical immunosensors and aptasensors: antibiotics, bisphenol A, cocaine, ochratoxin A and estradiol. In each case, the immobilization procedures are described as well as the transduction schemes and the limits of detection. It is shown that limits of detections are generally two to three orders of magnitude lower for immunosensors than for aptasensors, due to the highest affinities of antibodies. No significant progresses have been made to improve these affinities, but transduction schemes were improved instead, which lead to a regular improvement of the limit of detections corresponding to ca. five orders of magnitude over these last 10 years. These progresses depend on the target, however. PMID:26938570

Receptor Tyrosine Kinase Ubiquitination and De-Ubiquitination in Signal Transduction and Receptor Trafficking

PubMed Central

Critchley, William R.; Pellet-Many, Caroline; Ringham-Terry, Benjamin; Zachary, Ian C.; Ponnambalam, Sreenivasan

2018-01-01

Receptor tyrosine kinases (RTKs) are membrane-based sensors that enable rapid communication between cells and their environment. Evidence is now emerging that interdependent regulatory mechanisms, such as membrane trafficking, ubiquitination, proteolysis and gene expression, have substantial effects on RTK signal transduction and cellular responses. Different RTKs exhibit both basal and ligand-stimulated ubiquitination, linked to trafficking through different intracellular compartments including the secretory pathway, plasma membrane, endosomes and lysosomes. The ubiquitin ligase superfamily comprising the E1, E2 and E3 enzymes are increasingly implicated in this post-translational modification by adding mono- and polyubiquitin tags to RTKs. Conversely, removal of these ubiquitin tags by proteases called de-ubiquitinases (DUBs) enables RTK recycling for another round of ligand sensing and signal transduction. The endocytosis of basal and activated RTKs from the plasma membrane is closely linked to controlled proteolysis after trafficking and delivery to late endosomes and lysosomes. Proteolytic RTK fragments can also have the capacity to move to compartments such as the nucleus and regulate gene expression. Such mechanistic diversity now provides new opportunities for modulating RTK-regulated cellular responses in health and disease states. PMID:29543760

An effective method for adenoviral-mediated delivery of small interfering RNA into mesenchymal stem cells.

PubMed

Forte, Amalia; Napolitano, Marco A; Cipollaro, Marilena; Giordano, Antonio; Cascino, Antonino; Galderisi, Umberto

2007-02-01

Mesenchymal stem cells (MSCs) promise as a main actor of cell-based therapeutic strategies, due to their intrinsic ability to differentiate along different mesenchymal cell lineages, able to repair the diseased or injured tissue in which they are localized. The application of MSCs in therapies requires an in depth knowledge of their biology and of the molecular mechanisms leading to MSC multilineage differentiation. The knockdown of target genes through small interfering RNA (siRNA) carried by adenoviruses (Ad) represents a valid tool for the study of the role of specific molecules in cell biology. Unfortunately, MSCs are poorly transfected by conventional Ad serotype 5 (Ad5) vectors. We set up a method to obtain a very efficient transduction of rat MSCs with low doses of unmodified Ad5, carrying the siRNA targeted against the mRNA coding for Rb2/p130 (Ad-siRNA-Rb2), which plays a fundamental role in cell differentiation. This method allowed a 95% transduction rate of Ad-siRNA in MSC, along with a siRNA-mediated 85% decrease of Rb2/p130 mRNA and a 70% decrease of Rb2/p130 protein 48 h after transduction with 50 multiplicities of infection (MOIs) of Ad5. The effect on Rb2/p130 protein persisted 15 days after transduction. Finally, Ad-siRNA did not compromise the viability of transduced MSCs neither induced any cell cycle modification. The effective Ad-siRNA-Rb2 we constructed, together with the efficient method of delivery in MSCs we set up, will allow an in depth analysis of the role of Rb2/p130 in MSC biology and multilineage differentiation.

Heavy metal accumulation and signal transduction in herbaceous and woody plants: Paving the way for enhancing phytoremediation efficiency.

PubMed

Luo, Zhi-Bin; He, Jiali; Polle, Andrea; Rennenberg, Heinz

2016-11-01

Heavy metal (HM)-accumulating herbaceous and woody plants are employed for phytoremediation. To develop improved strategies for enhancing phytoremediation efficiency, knowledge of the microstructural, physiological and molecular responses underlying HM-accumulation is required. Here we review the progress in understanding the structural, physiological and molecular mechanisms underlying HM uptake, transport, sequestration and detoxification, as well as the regulation of these processes by signal transduction in response to HM exposure. The significance of genetic engineering for enhancing phytoremediation efficiency is also discussed. In herbaceous plants, HMs are taken up by roots and transported into the root cells via transmembrane carriers for nutritional ions. The HMs absorbed by root cells can be further translocated to the xylem vessels and unloaded into the xylem sap, thereby reaching the aerial parts of plants. HMs can be sequestered in the cell walls, vacuoles and the Golgi apparatuses. Plant roots initially perceive HM stress and trigger the signal transduction, thereby mediating changes at the molecular, physiological, and microstructural level. Signaling molecules such as phytohormones, reactive oxygen species (ROS) and nitric oxide (NO), modulate plant responses to HMs via differentially expressed genes, activation of the antioxidative system and coordinated cross talk among different signaling molecules. A number of genes participated in HM uptake, transport, sequestration and detoxification have been functionally characterized and transformed to target plants for enhancing phytoremediation efficiency. Fast growing woody plants hold an advantage over herbaceous plants for phytoremediation in terms of accumulation of high HM-amounts in their large biomass. Presumably, woody plants accumulate HMs using similar mechanisms as herbaceous counterparts, but the processes of HM accumulation and signal transduction can be more complex in woody plants. Copyright © 2016 Elsevier Inc. All rights reserved.

Reduced modeling of signal transduction – a modular approach

PubMed Central

Koschorreck, Markus; Conzelmann, Holger; Ebert, Sybille; Ederer, Michael; Gilles, Ernst Dieter

2007-01-01

Background Combinatorial complexity is a challenging problem in detailed and mechanistic mathematical modeling of signal transduction. This subject has been discussed intensively and a lot of progress has been made within the last few years. A software tool (BioNetGen) was developed which allows an automatic rule-based set-up of mechanistic model equations. In many cases these models can be reduced by an exact domain-oriented lumping technique. However, the resulting models can still consist of a very large number of differential equations. Results We introduce a new reduction technique, which allows building modularized and highly reduced models. Compared to existing approaches further reduction of signal transduction networks is possible. The method also provides a new modularization criterion, which allows to dissect the model into smaller modules that are called layers and can be modeled independently. Hallmarks of the approach are conservation relations within each layer and connection of layers by signal flows instead of mass flows. The reduced model can be formulated directly without previous generation of detailed model equations. It can be understood and interpreted intuitively, as model variables are macroscopic quantities that are converted by rates following simple kinetics. The proposed technique is applicable without using complex mathematical tools and even without detailed knowledge of the mathematical background. However, we provide a detailed mathematical analysis to show performance and limitations of the method. For physiologically relevant parameter domains the transient as well as the stationary errors caused by the reduction are negligible. Conclusion The new layer based reduced modeling method allows building modularized and strongly reduced models of signal transduction networks. Reduced model equations can be directly formulated and are intuitively interpretable. Additionally, the method provides very good approximations especially for macroscopic variables. It can be combined with existing reduction methods without any difficulties. PMID:17854494

Elucidating the Functional Roles of Spatial Organization in Cross-Membrane Signal Transduction by a Hybrid Simulation Method.

PubMed

Chen, Jiawen; Xie, Zhong-Ru; Wu, Yinghao

2016-07-01

The ligand-binding of membrane receptors on cell surfaces initiates the dynamic process of cross-membrane signal transduction. It is an indispensable part of the signaling network for cells to communicate with external environments. Recent experiments revealed that molecular components in signal transduction are not randomly mixed, but spatially organized into distinctive patterns. These patterns, such as receptor clustering and ligand oligomerization, lead to very different gene expression profiles. However, little is understood about the molecular mechanisms and functional impacts of this spatial-temporal regulation in cross-membrane signal transduction. In order to tackle this problem, we developed a hybrid computational method that decomposes a model of signaling network into two simulation modules. The physical process of binding between receptors and ligands on cell surfaces are simulated by a diffusion-reaction algorithm, while the downstream biochemical reactions are modeled by stochastic simulation of Gillespie algorithm. These two processes are coupled together by a synchronization framework. Using this method, we tested the dynamics of a simple signaling network in which the ligand binding of cell surface receptors triggers the phosphorylation of protein kinases, and in turn regulates the expression of target genes. We found that spatial aggregation of membrane receptors at cellular interfaces is able to either amplify or inhibit downstream signaling outputs, depending on the details of clustering mechanism. Moreover, by providing higher binding avidity, the co-localization of ligands into multi-valence complex modulates signaling in very different ways that are closely related to the binding affinity between ligand and receptor. We also found that the temporal oscillation of the signaling pathway that is derived from genetic feedback loops can be modified by the spatial clustering of membrane receptors. In summary, our method demonstrates the functional importance of spatial organization in cross-membrane signal transduction. The method can be applied to any specific signaling pathway in cells.

Bioinspired integrated nanosystems based on solid-state nanopores: “iontronic” transduction of biological, chemical and physical stimuli

PubMed Central

Pérez-Mitta, Gonzalo; Albesa, Alberto G.; Trautmann, Christina; Toimil-Molares, María Eugenia

2017-01-01

The ability of living systems to respond to stimuli and process information has encouraged scientists to develop integrated nanosystems displaying similar functions and capabilities. In this regard, biological pores have been a source of inspiration due to their exquisite control over the transport of ions within cells, a feature that ultimately plays a major role in multiple physiological processes, e.g. transduction of physical stimuli into nervous signals. Developing abiotic nanopores, which respond to certain chemical, biological or physical inputs producing “iontronic” signals, is now a reality thanks to the combination of “soft” surface science with nanofabrication techniques. The interplay between the functional richness of predesigned molecular components and the remarkable physical characteristics of nanopores plays a critical role in the rational integration of molecular functions into nanopore environments, permitting us to envisage nanopore-based biomimetic integrated nanosystems that respond to a variety of external stimuli such as pH, redox potential, molecule concentration, temperature, or light. Transduction of these stimuli into a predefined “iontronic” response can be amplified by exploiting nanoconfinement and physico-chemical effects such as charge distribution, steric constraints, equilibria displacement, or local changes in ionic concentration, to name but a few examples. While in past decades the focus has been mostly on their fundamental aspects and the in-depth study of their interesting transport properties, for several years now nanopore research has started to shift towards specific practical applications. This work is dedicated to bringing together the latest developments in the use of nanopores as “iontronic” transducing elements. Our aim is to show the wide potential of abiotic nanopores in sensing and signal transduction and also to promote the potential of this technology among doctoral students, postdocs, and researchers. We believe that even a casual reader of this perspective will not fail to be impressed by the wealth of opportunities that solid-state nanopores can offer to the transduction of biological, physical and chemical stimuli. PMID:28572900

Grounded and embodied mathematical cognition: Promoting mathematical insight and proof using action and language.

PubMed

Nathan, Mitchell J; Walkington, Candace

2017-01-01

We develop a theory of grounded and embodied mathematical cognition (GEMC) that draws on action-cognition transduction for advancing understanding of how the body can support mathematical reasoning. GEMC proposes that participants' actions serve as inputs capable of driving the cognition-action system toward associated cognitive states. This occurs through a process of transduction that promotes valuable mathematical insights by eliciting dynamic depictive gestures that enact spatio-temporal properties of mathematical entities. Our focus here is on pre-college geometry proof production. GEMC suggests that action alone can foster insight but is insufficient for valid proof production if action is not coordinated with language systems for propositionalizing general properties of objects and space. GEMC guides the design of a video game-based learning environment intended to promote students' mathematical insights and informal proofs by eliciting dynamic gestures through in-game directed actions. GEMC generates several hypotheses that contribute to theories of embodied cognition and to the design of science, technology, engineering, and mathematics (STEM) education interventions. Pilot study results with a prototype video game tentatively support theory-based predictions regarding the role of dynamic gestures for fostering insight and proof-with-insight, and for the role of action coupled with language to promote proof-with-insight. But the pilot yields mixed results for deriving in-game interventions intended to elicit dynamic gesture production. Although our central purpose is an explication of GEMC theory and the role of action-cognition transduction, the theory-based video game design reveals the potential of GEMC to improve STEM education, and highlights the complex challenges of connecting embodiment research to education practices and learning environment design.

Ionic signaling in plant gravity and touch responses

NASA Technical Reports Server (NTRS)

Massa, Gioia D.; Fasano, Jeremiah M.; Gilroy, Simon

2003-01-01

Plant roots are optimized to exploit resources from the soil and as each root explores this environment it will encounter a range of biotic and abiotic stimuli to which it must respond. Therefore, each root must possess a sensory array capable of monitoring and integrating these diverse stimuli to direct the appropriate growth response. Touch and gravity represent two of the biophysical stimuli that plants must integrate. As sensing both of these signals requires mechano-transduction of biophysical forces to biochemical signaling events, it is likely that they share signal transduction elements. These common signaling components may allow for cross-talk and so integration of thigmotropic and gravitropic responses. Indeed, signal transduction events in both plant touch and gravity sensing are thought to include Ca(2+)- and pH-dependent events. Additionally, it seems clear that the systems responsible for root touch and gravity response interact to generate an integrated growth response. Thus, primary and lateral roots of Arabidopsis respond to mechanical stimuli by eliciting tropic growth that is likely part of a growth strategy employed by the root to circumvent obstacles in the soil. Also, the mechano-signaling induced by encountering an obstacle apparently down-regulates the graviperception machinery to allow this kind of avoidance response. The challenge for future research will be to define how the cellular signaling events in the root cap facilitate this signal integration and growth regulation. In addition, whether other stimuli are likewise integrated with the graviresponse via signal transduction system cross-talk is an important question that remains to be answered.

Resistance gene transfer: induction of transducing phage by sub-inhibitory concentrations of antimicrobials is not correlated to induction of lytic phage

PubMed Central

Stanczak-Mrozek, Kinga I.; Laing, Ken G.

2017-01-01

Objectives: Horizontal gene transfer of antimicrobial resistance (AMR) genes between clinical isolates via transduction is poorly understood. MRSA are opportunistic pathogens resistant to all classes of antimicrobial agents but currently no strains are fully drug resistant. AMR gene transfer between Staphylococcus aureus isolates is predominantly due to generalized transduction via endogenous bacteriophage, and recent studies have suggested transfer is elevated during host colonization. The aim was to investigate whether exposure to sub-MIC concentrations of antimicrobials triggers bacteriophage induction and/or increased efficiency of AMR gene transfer. Methods: Isolates from MRSA carriers were exposed to nine antimicrobials and supernatants were compared for lytic phage particles and ability to transfer an AMR gene. A new technology, droplet digital PCR, was used to measure the concentration of genes in phage particles. Results: All antibiotics tested induced lytic phage and AMR gene transduction, although the ratio of transducing particles to lytic particles differed substantially for each antibiotic. Mupirocin induced the highest ratio of transducing versus lytic particles. Gentamicin and novobiocin reduced UV-induced AMR transduction. The genes carried in phage particles correlated with AMR transfer or lytic particle activity, suggesting antimicrobials influence which DNA sequences are packaged into phage particles. Conclusions: Sub-inhibitory antibiotics induce AMR gene transfer between clinical MRSA, while combination therapy with an inhibiting antibiotic could potentially alter AMR gene packaging into phage particles, reducing AMR transfer. In a continually evolving environment, pathogens have an advantage if they can transfer DNA while lowering the risk of lytic death. PMID:28369562

CRISPR-Cas-Mediated Phage Resistance Enhances Horizontal Gene Transfer by Transduction.

PubMed

Watson, Bridget N J; Staals, Raymond H J; Fineran, Peter C

2018-02-13

A powerful contributor to prokaryotic evolution is horizontal gene transfer (HGT) through transformation, conjugation, and transduction, which can be advantageous, neutral, or detrimental to fitness. Bacteria and archaea control HGT and phage infection through CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins) adaptive immunity. Although the benefits of resisting phage infection are evident, this can come at a cost of inhibiting the acquisition of other beneficial genes through HGT. Despite the ability of CRISPR-Cas to limit HGT through conjugation and transformation, its role in transduction is largely overlooked. Transduction is the phage-mediated transfer of bacterial DNA between cells and arguably has the greatest impact on HGT. We demonstrate that in Pectobacterium atrosepticum , CRISPR-Cas can inhibit the transduction of plasmids and chromosomal loci. In addition, we detected phage-mediated transfer of a large plant pathogenicity genomic island and show that CRISPR-Cas can inhibit its transduction. Despite these inhibitory effects of CRISPR-Cas on transduction, its more common role in phage resistance promotes rather than diminishes HGT via transduction by protecting bacteria from phage infection. This protective effect can also increase transduction of phage-sensitive members of mixed populations. CRISPR-Cas systems themselves display evidence of HGT, but little is known about their lateral dissemination between bacteria and whether transduction can contribute. We show that, through transduction, bacteria can acquire an entire chromosomal CRISPR-Cas system, including cas genes and phage-targeting spacers. We propose that the positive effect of CRISPR-Cas phage immunity on enhancing transduction surpasses the rarer cases where gene flow by transduction is restricted. IMPORTANCE The generation of genetic diversity through acquisition of DNA is a powerful contributor to microbial evolution and occurs through transformation, conjugation, and transduction. Of these, transduction, the phage-mediated transfer of bacterial DNA, is arguably the major route for genetic exchange. CRISPR-Cas adaptive immune systems control gene transfer by conjugation and transformation, but transduction has been mostly overlooked. Our results indicate that CRISPR-Cas can impede, but typically enhances the transduction of plasmids, chromosomal genes, and pathogenicity islands. By limiting wild-type phage replication, CRISPR-Cas immunity increases transduction in both phage-resistant and -sensitive members of mixed populations. Furthermore, we demonstrate mobilization of a chromosomal CRISPR-Cas system containing phage-targeting spacers by generalized transduction, which might partly account for the uneven distribution of these systems in nature. Overall, the ability of CRISPR-Cas to promote transduction reveals an unexpected impact of adaptive immunity on horizontal gene transfer, with broader implications for microbial evolution. Copyright © 2018 Watson et al.

Proteomic Research Funding Opportunity | Office of Cancer Clinical Proteomics Research

Cancer.gov

To expand the understanding of how cells sense and respond to changes in their physical environment, the NCI is seeking to perform proteomic assays on the panel of cell lines grown on a variety of substrates. These assays will provide insight into changes in protein levels or phosphorylation changes that could reflect the activity of mechano-transduction pathways.

Cellular innate immunity and restriction of viral infection: implications for lentiviral gene therapy in human hematopoietic cells.

PubMed

Kajaste-Rudnitski, Anna; Naldini, Luigi

2015-04-01

Hematopoietic gene therapy has tremendous potential to treat human disease. Nevertheless, for gene therapy to be efficacious, effective gene transfer into target cells must be reached without inducing detrimental effects on their biological properties. This remains a great challenge for the field as high vector doses and prolonged ex vivo culture conditions are still required to reach significant transduction levels of clinically relevant human hematopoietic stem and progenitor cells (HSPCs), while other potential target cells such as primary macrophages can hardly be transduced. The reasons behind poor permissiveness of primary human hematopoietic cells to gene transfer partly reside in the retroviral origin of lentiviral vectors (LVs). In particular, host antiviral factors referred to as restriction factors targeting the retroviral life cycle can hamper LV transduction efficiency. Furthermore, LVs may activate innate immune sensors not only in differentiated hematopoietic cells but also in HSPCs, with potential consequences on transduction efficiency as well as their biological properties. Therefore, better understanding of the vector-host interactions in the context of hematopoietic gene transfer is important for the development of safer and more efficient gene therapy strategies. In this review, we briefly summarize the current knowledge regarding innate immune recognition of lentiviruses in primary human hematopoietic cells as well as discuss its relevance for LV-based ex vivo gene therapy approaches.

Signal Transduction: From the Atomic Age to the Post-Genomic Era

PubMed Central

Thorner, Jeremy; Hunter, Tony; Cantley, Lewis C.; Sever, Richard

2014-01-01

We have come a long way in the 55 years since Edmond Fischer and the late Edwin Krebs discovered that the activity of glycogen phosphorylase is regulated by reversible protein phosphorylation. Many of the fundamental molecular mechanisms that operate in biological signaling have since been characterized and the vast web of interconnected pathways that make up the cellular signaling network has been mapped in considerable detail. Nonetheless, it is important to consider how fast this field is still moving and the issues at the current boundaries of our understanding. One must also appreciate what experimental strategies have allowed us to attain our present level of knowledge. We summarize here some key issues (both conceptual and methodological), raise unresolved questions, discuss potential pitfalls, and highlight areas in which our understanding is still rudimentary. We hope these wide-ranging ruminations will be useful to investigators who carry studies of signal transduction forward during the rest of the 21st century. PMID:25359498

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

PubMed

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. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Therapeutic peptides for cancer therapy. Part I - peptide inhibitors of signal transduction cascades.

PubMed

Bidwell, Gene L; Raucher, Drazen

2009-10-01

Therapeutic peptides have great potential as anticancer agents owing to their ease of rational design and target specificity. However, their utility in vivo is limited by low stability and poor tumor penetration. The authors review the development of peptide inhibitors with potential for cancer therapy. Peptides that inhibit signal transduction cascades are discussed. The authors searched Medline for articles concerning the development of therapeutic peptides and their delivery. Given our current knowledge of protein sequences, structures and interaction interfaces, therapeutic peptides that inhibit interactions of interest are easily designed. These peptides are advantageous because they are highly specific for the interaction of interest, and they are much more easily developed than small molecule inhibitors of the same interactions. The main hurdle to application of peptides for cancer therapy is their poor pharmacokinetic and biodistribution parameters. Therefore, successful development of peptide delivery vectors could potentially make possible the use of this new and very promising class of anticancer agents.

Distant Supervision with Transductive Learning for Adverse Drug Reaction Identification from Electronic Medical Records

PubMed Central

Ikeda, Mitsuru

2017-01-01

Information extraction and knowledge discovery regarding adverse drug reaction (ADR) from large-scale clinical texts are very useful and needy processes. Two major difficulties of this task are the lack of domain experts for labeling examples and intractable processing of unstructured clinical texts. Even though most previous works have been conducted on these issues by applying semisupervised learning for the former and a word-based approach for the latter, they face with complexity in an acquisition of initial labeled data and ignorance of structured sequence of natural language. In this study, we propose automatic data labeling by distant supervision where knowledge bases are exploited to assign an entity-level relation label for each drug-event pair in texts, and then, we use patterns for characterizing ADR relation. The multiple-instance learning with expectation-maximization method is employed to estimate model parameters. The method applies transductive learning to iteratively reassign a probability of unknown drug-event pair at the training time. By investigating experiments with 50,998 discharge summaries, we evaluate our method by varying large number of parameters, that is, pattern types, pattern-weighting models, and initial and iterative weightings of relations for unlabeled data. Based on evaluations, our proposed method outperforms the word-based feature for NB-EM (iEM), MILR, and TSVM with F1 score of 11.3%, 9.3%, and 6.5% improvement, respectively. PMID:29090077

Testing piezoelectric sensors in a nuclear reactor environment

NASA Astrophysics Data System (ADS)

Reinhardt, Brian T.; Suprock, Andy; Tittmann, Bernhard

2017-02-01

Several Department of Energy Office of Nuclear Energy (DOE-NE) programs, such as the Fuel Cycle Research and Development (FCRD), Advanced Reactor Concepts (ARC), Light Water Reactor Sustainability, and Next Generation Nuclear Power Plants (NGNP), are investigating new fuels, materials, and inspection paradigms for advanced and existing reactors. A key objective of such programs is to understand the performance of these fuels and materials during irradiation. In DOE-NE's FCRD program, ultrasonic based technology was identified as a key approach that should be pursued to obtain the high-fidelity, high-accuracy data required to characterize the behavior and performance of new candidate fuels and structural materials during irradiation testing. The radiation, high temperatures, and pressure can limit the available tools and characterization methods. In this work piezoelectric transducers capable of making these measurements are developed. Specifically, three piezoelectric sensors (Bismuth Titanate, Aluminum Nitride, and Zinc Oxide) are tested in the Massachusetts Institute of Technology Research reactor to a fast neutron fluence of 8.65×1020 nf/cm2. It is demonstrated that Bismuth Titanate is capable of transduction up to 5 × 1020 nf/cm2, Zinc Oxide is capable of transduction up to at least 6.27 × 1020 nf/cm2, and Aluminum Nitride is capable of transduction up to at least 8.65 × 1020 nf/cm2.

Modulators of Stomatal Lineage Signal Transduction Alter Membrane Contact Sites and Reveal Specialization among ERECTA Kinases.

PubMed

Ho, Chin-Min Kimmy; Paciorek, Tomasz; Abrash, Emily; Bergmann, Dominique C

2016-08-22

Signal transduction from a cell's surface to its interior requires dedicated signaling elements and a cellular environment conducive to signal propagation. Plant development, defense, and homeostasis rely on plasma membrane receptor-like kinases to perceive endogenous and environmental signals, but little is known about their immediate downstream targets and signaling modifiers. Using genetics, biochemistry, and live-cell imaging, we show that the VAP-RELATED SUPPRESSOR OF TMM (VST) family is required for ERECTA-mediated signaling in growth and cell-fate determination and reveal a role for ERECTA-LIKE2 in modulating signaling by its sister kinases. We show that VSTs are peripheral plasma membrane proteins that can form complexes with integral ER-membrane proteins, thereby potentially influencing the organization of the membrane milieu to promote efficient and differential signaling from the ERECTA-family members to their downstream intracellular targets. Copyright © 2016 Elsevier Inc. All rights reserved.

Experiments and appropriate facilities for plant physiology research in space

NASA Astrophysics Data System (ADS)

Lork, W.

Light is a very essential parameter in a plant's life. Changing the quality and/or quantity of illumination will not only determine the further development (photomorphogenesis), but also effect spontaneous responses like curvatures (phototropism). But there are several still unknown links in the signal transduction chain from the perception of the light signals to the terminal response. It is known from ground-based experiments, that part of this signal transduction path is congruous with that of gravitational signals. Biosample is a technology development programme, which enables sophisticated experiments with whole plants in a microgravity environment. It allows complex sequences of gravitational- and light-stimuli with simultaneous recording of the plant's response (e.g. curvature of the stem) by video. This facility in union with new genetic mutants, which are less- or insensitive to light, gravity or both, are convenient tools for progress in plant physiology research.

Campylobacter jejuni transducer like proteins: Chemotaxis and beyond

PubMed Central

Chandrashekhar, Kshipra; Kassem, Issmat I.; Rajashekara, Gireesh

2017-01-01

ABSTRACT Chemotaxis, a process that mediates directional motility toward or away from chemical stimuli (chemoeffectors/ligands that can be attractants or repellents) in the environment, plays an important role in the adaptation of Campylobacter jejuni to disparate niches. The chemotaxis system consists of core signal transduction proteins and methyl-accepting-domain-containing Transducer like proteins (Tlps). Ligands binding to Tlps relay a signal to chemotaxis proteins in the cytoplasm which initiate a signal transduction cascade, culminating into a directional flagellar movement. Tlps facilitate substrate-specific chemotaxis in C. jejuni, which plays an important role in the pathogen's adaptation, pathobiology and colonization of the chicken gastrointestinal tract. However, the role of Tlps in C. jejuni's host tissue specific colonization, physiology and virulence remains not completely understood. Based on recent studies, it can be predicted that Tlps might be important targets for developing strategies to control C. jejuni via vaccines and antimicrobials. PMID:28080213

Campylobacter jejuni transducer like proteins: Chemotaxis and beyond.

PubMed

Chandrashekhar, Kshipra; Kassem, Issmat I; Rajashekara, Gireesh

2017-07-04

Chemotaxis, a process that mediates directional motility toward or away from chemical stimuli (chemoeffectors/ligands that can be attractants or repellents) in the environment, plays an important role in the adaptation of Campylobacter jejuni to disparate niches. The chemotaxis system consists of core signal transduction proteins and methyl-accepting-domain-containing Transducer like proteins (Tlps). Ligands binding to Tlps relay a signal to chemotaxis proteins in the cytoplasm which initiate a signal transduction cascade, culminating into a directional flagellar movement. Tlps facilitate substrate-specific chemotaxis in C. jejuni, which plays an important role in the pathogen's adaptation, pathobiology and colonization of the chicken gastrointestinal tract. However, the role of Tlps in C. jejuni's host tissue specific colonization, physiology and virulence remains not completely understood. Based on recent studies, it can be predicted that Tlps might be important targets for developing strategies to control C. jejuni via vaccines and antimicrobials.

Testing the Vibrational Theory of Olfaction: A Bio-Organic Chemistry Laboratory Experiment Using Hooke's Law and Chirality

ERIC Educational Resources Information Center

Muthyala, Rajeev S.; Butani, Deepali; Nelson, Michelle; Tran, Kiet

2017-01-01

Sense of smell is one of the important senses that enables us to interact with our environment. The molecular basis of olfactory signal transduction is a fascinating area for organic chemistry educators to explore in terms of developing undergraduate laboratory activities at the interface of chemistry and biology. In this paper, a guided-inquiry…

Toxicity of Pseudomonas fluorescens strain Pf-5 to Drosophila larvae is due to downstream gene targets of the GacA/GacS signal transduction system

USDA-ARS?s Scientific Manuscript database

Given the vast number of microorganisms in the environment, surprisingly, only a few are lethal or cause morbidity to host organisms. Pseudomonas spp are a diverse genus of Gram-negative bacteria commonly found in soil, water, or in association with plants and animals. Pseudomonas fluorescens has be...

Psoralen and Ultraviolet A Light Treatment Directly Affects Phosphatidylinositol 3-Kinase Signal Transduction by Altering Plasma Membrane Packing*

PubMed Central

Van Aelst, Britt; Devloo, Rosalie; Zachée, Pierre; t'Kindt, Ruben; Sandra, Koen; Vandekerckhove, Philippe; Compernolle, Veerle; Feys, Hendrik B.

2016-01-01

Psoralen and ultraviolet A light (PUVA) are used to kill pathogens in blood products and as a treatment of aberrant cell proliferation in dermatitis, cutaneous T-cell lymphoma, and graft-versus-host disease. DNA damage is well described, but the direct effects of PUVA on cell signal transduction are poorly understood. Because platelets are anucleate and contain archetypal signal transduction machinery, they are ideally suited to address this. Lipidomics on platelet membrane extracts showed that psoralen forms adducts with unsaturated carbon bonds of fatty acyls in all major phospholipid classes after PUVA. Such adducts increased lipid packing as measured by a blue shift of an environment-sensitive fluorescent probe in model liposomes. Furthermore, the interaction of these liposomes with lipid order-sensitive proteins like amphipathic lipid-packing sensor and α-synuclein was inhibited by PUVA. In platelets, PUVA caused poor membrane binding of Akt and Bruton's tyrosine kinase effectors following activation of the collagen glycoprotein VI and thrombin protease-activated receptor (PAR) 1. This resulted in defective Akt phosphorylation despite unaltered phosphatidylinositol 3,4,5-trisphosphate levels. Downstream integrin activation was furthermore affected similarly by PUVA following PAR1 (effective half-maximal concentration (EC50), 8.4 ± 1.1 versus 4.3 ± 1.1 μm) and glycoprotein VI (EC50, 1.61 ± 0.85 versus 0.26 ± 0.21 μg/ml) but not PAR4 (EC50, 50 ± 1 versus 58 ± 1 μm) signal transduction. Our findings were confirmed in T-cells from graft-versus-host disease patients treated with extracorporeal photopheresis, a form of systemic PUVA. In conclusion, PUVA increases the order of lipid phases by covalent modification of phospholipids, thereby inhibiting membrane recruitment of effector kinases. PMID:27687726

Nanoscale methods for single-molecule electrochemistry.

PubMed

Mathwig, Klaus; Aartsma, Thijs J; Canters, Gerard W; Lemay, Serge G

2014-01-01

The development of experiments capable of probing individual molecules has led to major breakthroughs in fields ranging from molecular electronics to biophysics, allowing direct tests of knowledge derived from macroscopic measurements and enabling new assays that probe population heterogeneities and internal molecular dynamics. Although still somewhat in their infancy, such methods are also being developed for probing molecular systems in solution using electrochemical transduction mechanisms. Here we outline the present status of this emerging field, concentrating in particular on optical methods, metal-molecule-metal junctions, and electrochemical nanofluidic devices.

Non-symbiotic haemoglobins-What's happening beyond nitric oxide scavenging?

PubMed

Hill, Robert D

2012-01-01

Non-symbiotic haemoglobins have been an active research topic for over 30 years, during which time a considerable portfolio of knowledge has accumulated relative to their chemical and molecular properties, and their presence and mode of induction in plants. While progress has been made towards understanding their physiological role, there remain a number of unanswered questions with respect to their biological function. This review attempts to update recent progress in this area and to introduce a hypothesis as to how non-symbiotic haemoglobins might participate in regulating hormone signal transduction. Advances have been made towards understanding the structural nuances that explain some of the differences in ligand association characteristics of class 1 and class 2 non-symbiotic haemoglobins. Non-symbiotic haemoglobins have been found to function in seed development and germination, flowering, root development and differentiation, abiotic stress responses, pathogen invasion and symbiotic bacterial associations. Microarray analyses under various stress conditions yield uneven results relative to non-symbiotic haemoglobin expression. Increasing evidence of the role of nitric oxide (NO) in hormone responses and the known involvement of non-symbiotic haemoglobins in scavenging NO provide opportunities for fruitful research, particularly at the cellular level. Circumstantial evidence suggests that non-symbiotic haemoglobins may have a critical function in the signal transduction pathways of auxin, ethylene, jasmonic acid, salicylic acid, cytokinin and abscisic acid. There is a strong need for research on haemoglobin gene expression at the cellular level relative to hormone signal transduction.

Non-symbiotic haemoglobins—What's happening beyond nitric oxide scavenging?

PubMed Central

Hill, Robert D.

2012-01-01

Background and aims Non-symbiotic haemoglobins have been an active research topic for over 30 years, during which time a considerable portfolio of knowledge has accumulated relative to their chemical and molecular properties, and their presence and mode of induction in plants. While progress has been made towards understanding their physiological role, there remain a number of unanswered questions with respect to their biological function. This review attempts to update recent progress in this area and to introduce a hypothesis as to how non-symbiotic haemoglobins might participate in regulating hormone signal transduction. Principal results Advances have been made towards understanding the structural nuances that explain some of the differences in ligand association characteristics of class 1 and class 2 non-symbiotic haemoglobins. Non-symbiotic haemoglobins have been found to function in seed development and germination, flowering, root development and differentiation, abiotic stress responses, pathogen invasion and symbiotic bacterial associations. Microarray analyses under various stress conditions yield uneven results relative to non-symbiotic haemoglobin expression. Increasing evidence of the role of nitric oxide (NO) in hormone responses and the known involvement of non-symbiotic haemoglobins in scavenging NO provide opportunities for fruitful research, particularly at the cellular level. Conclusions Circumstantial evidence suggests that non-symbiotic haemoglobins may have a critical function in the signal transduction pathways of auxin, ethylene, jasmonic acid, salicylic acid, cytokinin and abscisic acid. There is a strong need for research on haemoglobin gene expression at the cellular level relative to hormone signal transduction. PMID:22479675

Cell Proliferation, Reactive Oxygen and Cellular Glutathione

PubMed Central

Day, Regina M.; Suzuki, Yuichiro J.

2005-01-01

A variety of cellular activities, including metabolism, growth, and death, are regulated and modulated by the redox status of the environment. A biphasic effect has been demonstrated on cellular proliferation with reactive oxygen species (ROS)—especially hydrogen peroxide and superoxide—in which low levels (usually submicromolar concentrations) induce growth but higher concentrations (usually >10–30 micromolar) induce apoptosis or necrosis. This phenomenon has been demonstrated for primary, immortalized and transformed cell types. However, the mechanism of the proliferative response to low levels of ROS is not well understood. Much of the work examining the signal transduction by ROS, including H2O2, has been performed using doses in the lethal range. Although use of higher ROS doses have allowed the identification of important signal transduction pathways, these pathways may be activated by cells only in association with ROS-induced apoptosis and necrosis, and may not utilize the same pathways activated by lower doses of ROS associated with increased cell growth. Recent data has shown that low levels of exogenous H2O2 up-regulate intracellular glutathione and activate the DNA binding activity toward antioxidant response element. The modulation of the cellular redox environment, through the regulation of cellular glutathione levels, may be a part of the hormetic effect shown by ROS on cell growth. PMID:18648617

Impact of radiations on the electromechanical properties of materials and on the piezoresistive and capacitive transduction mechanisms used in microsystems

NASA Astrophysics Data System (ADS)

Francis, Laurent A.; Gkotsis, Petros; Kilchytska, Valeriya; Tang, Xiaohui; Druart, Sylvain; Raskin, Jean-Pierre; Flandre, Denis

2013-03-01

The impact of different types of radiation on the electromechanical properties of materials used in microfabrication and on the capacitive and piezoresistive transduction mechanisms of MEMS is investigated. MEMS technologies could revolutionize avionics, satellite and space applications provided that the stress conditions which can compromise the reliability of microsystems in these environments are well understood. Initial tests with MEMS revealed a vulnerability of some types of devices to radiation induced dielectric charging, a physical mechanism which also affects microelectronics, however integration of novel functional materials in microfabrication and the current trend to substitute SiO2 with high-k dielectrics in ICs pose new questions regarding reliability in radiation environments. The performance of MEMS devices with moving parts could also degrade due to radiation induced changes in the mechanical properties of the materials. It is thus necessary to investigate the effects of radiation on the properties of thin films used in microfabrication and here we report on tests with γ, high energy protons and fast neutrons radiation. Prototype SOI based MEMS magnetometers which were developed in UCL are also used as test vehicles to investigate radiation effects on the reliability of magnetically actuated and capacitively coupled MEMS.

Framing the nano-biointeractions by proteomics

NASA Astrophysics Data System (ADS)

Sabella, S.; Maiorano, G.; Rizzello, L.; Kote, S.; Cingolani, R.; Pompa, P. P.

2012-03-01

Knowledge of the molecular mechanisms underlying the interactions between nanomaterials and living systems is fundamental for providing more effective products for nanomedicine and drug delivery. Controlling the response of cells/bacteria (such as activation of inflammatory processes or apoptosis/necrosis in tumor cells or pathogenic bacteria) by tuning specific properties of the nanomaterials is ultimately the challenging goal. Notably, this may also provide crucial information in the assessment of any toxic risks induced by nanoparticles on humans. However, in studying the nano-biointeractions, it is imperative to take into account the dynamic evolutions of nanoparticles in the biological environments (in terms of protein corona formation, size and charge changes) in synergy with the dynamic events occurring in cells, including signal transduction, metabolic processes, homeostasis and membrane trafficking. In this context, we discuss the impact of analytical technologies, especially in the field of proteomics, which can provide major insights into the processes affecting the NPs surface as well as the cells and bacteria functionalities. In particular, we show that a precise control of the chemical-physical characteristics of the interacting nanoparticles or nanostructures may impact the cells by inducing changes in the proteomic profiles with direct consequences on their viability.

Arm-in-Arm Response Regulator Dimers Promote Intermolecular Signal Transduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, Anna W.; Satyshur, Kenneth A.; Moreno Morales, Neydis

2016-02-01

ABSTRACT Bacteriophytochrome photoreceptors (BphPs) and their cognate response regulators make up two-component signal transduction systems which direct bacteria to mount phenotypic responses to changes in environmental light quality. Most of these systems utilize single-domain response regulators to transduce signals through unknown pathways and mechanisms. Here we describe the photocycle and autophosphorylation kinetics of RtBphP1, a red light-regulated histidine kinase from the desert bacteriumRamlibacter tataouinensis. RtBphP1 undergoes red to far-red photoconversion with rapid thermal reversion to the dark state. RtBphP1 is autophosphorylated in the dark; this activity is inhibited under red light. The RtBphP1 cognate response regulator, theR. tataouinensisbacteriophytochrome response regulatormore » (RtBRR), and a homolog, AtBRR fromAgrobacterium tumefaciens, crystallize unexpectedly as arm-in-arm dimers, reliant on a conserved hydrophobic motif, hFWAhL (where h is a hydrophobic M, V, L, or I residue). RtBRR and AtBRR dimerize distinctly from four structurally characterized phytochrome response regulators found in photosynthetic organisms and from all other receiver domain homodimers in the Protein Data Bank. A unique cacodylate-zinc-histidine tag metal organic framework yielded single-wavelength anomalous diffraction phases and may be of general interest. Examination of the effect of the BRR stoichiometry on signal transduction showed that phosphorylated RtBRR is accumulated more efficiently than the engineered monomeric RtBRR (RtBRR mon) in phosphotransfer reactions. Thus, we conclude that arm-in-arm dimers are a relevant signaling intermediate in this class of two-component regulatory systems. IMPORTANCEBphP histidine kinases and their cognate response regulators comprise widespread red light-sensing two-component systems. Much work on BphPs has focused on structural understanding of light sensing and on enhancing the natural infrared fluorescence of these proteins, rather than on signal transduction or the resultant phenotypes. To begin to address this knowledge gap, we solved the crystal structures of two single-domain response regulators encoded by a region immediately downstream of that encoding BphPs. We observed a previously unknown arm-in-arm dimer linkage. Monomerization via deletion of the C-terminal dimerization motif had an inhibitory effect on net response regulator phosphorylation, underlining the importance of these unusual dimers for signal transduction.« less

Gibberellin biosynthesis and signal transduction is essential for internode elongation in deepwater rice.

PubMed

Ayano, Madoka; Kani, Takahiro; Kojima, Mikiko; Sakakibara, Hitoshi; Kitaoka, Takuya; Kuroha, Takeshi; Angeles-Shim, Rosalyn B; Kitano, Hidemi; Nagai, Keisuke; Ashikari, Motoyuki

2014-10-01

Under flooded conditions, the leaves and internodes of deepwater rice can elongate above the water surface to capture oxygen and prevent drowning. Our previous studies showed that three major quantitative trait loci (QTL) regulate deepwater-dependent internode elongation in deepwater rice. In this study, we investigated the age-dependent internode elongation in deepwater rice. We also investigated the relationship between deepwater-dependent internode elongation and the phytohormone gibberellin (GA) by physiological and genetic approach using a QTL pyramiding line (NIL-1 + 3 + 12). Deepwater rice did not show internode elongation before the sixth leaf stage under deepwater condition. Additionally, deepwater-dependent internode elongation occurred on the sixth and seventh internodes during the sixth leaf stage. These results indicate that deepwater rice could not start internode elongation until the sixth leaf stage. Ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS) method for the phytohormone contents showed a deepwater-dependent GA1 and GA4 accumulation in deepwater rice. Additionally, a GA inhibitor abolished deepwater-dependent internode elongation in deepwater rice. On the contrary, GA feeding mimicked internode elongation under ordinary growth conditions. However, mutations in GA biosynthesis and signal transduction genes blocked deepwater-dependent internode elongation. These data suggested that GA biosynthesis and signal transduction are essential for deepwater-dependent internode elongation in deepwater rice. © 2014 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

Wnt pathway curation using automated natural language processing: combining statistical methods with partial and full parse for knowledge extraction.

PubMed

Santos, Carlos; Eggle, Daniela; States, David J

2005-04-15

Wnt signaling is a very active area of research with highly relevant publications appearing at a rate of more than one per day. Building and maintaining databases describing signal transduction networks is a time-consuming and demanding task that requires careful literature analysis and extensive domain-specific knowledge. For instance, more than 50 factors involved in Wnt signal transduction have been identified as of late 2003. In this work we describe a natural language processing (NLP) system that is able to identify references to biological interaction networks in free text and automatically assembles a protein association and interaction map. A 'gold standard' set of names and assertions was derived by manual scanning of the Wnt genes website (http://www.stanford.edu/~rnusse/wntwindow.html) including 53 interactions involved in Wnt signaling. This system was used to analyze a corpus of peer-reviewed articles related to Wnt signaling including 3369 Pubmed and 1230 full text papers. Names for key Wnt-pathway associated proteins and biological entities are identified using a chi-squared analysis of noun phrases over-represented in the Wnt literature as compared to the general signal transduction literature. Interestingly, we identified several instances where generic terms were used on the website when more specific terms occur in the literature, and one typographic error on the Wnt canonical pathway. Using the named entity list and performing an exhaustive assertion extraction of the corpus, 34 of the 53 interactions in the 'gold standard' Wnt signaling set were successfully identified (64% recall). In addition, the automated extraction found several interactions involving key Wnt-related molecules which were missing or different from those in the canonical diagram, and these were confirmed by manual review of the text. These results suggest that a combination of NLP techniques for information extraction can form a useful first-pass tool for assisting human annotation and maintenance of signal pathway databases. The pipeline software components are freely available on request to the authors. dstates@umich.edu http://stateslab.bioinformatics.med.umich.edu/software.html.

Systems modelling methodology for the analysis of apoptosis signal transduction and cell death decisions.

PubMed

Rehm, Markus; Prehn, Jochen H M

2013-06-01

Systems biology and systems medicine, i.e. the application of systems biology in a clinical context, is becoming of increasing importance in biology, drug discovery and health care. Systems biology incorporates knowledge and methods that are applied in mathematics, physics and engineering, but may not be part of classical training in biology. We here provide an introduction to basic concepts and methods relevant to the construction and application of systems models for apoptosis research. We present the key methods relevant to the representation of biochemical processes in signal transduction models, with a particular reference to apoptotic processes. We demonstrate how such models enable a quantitative and temporal analysis of changes in molecular entities in response to an apoptosis-inducing stimulus, and provide information on cell survival and cell death decisions. We introduce methods for analyzing the spatial propagation of cell death signals, and discuss the concepts of sensitivity analyses that enable a prediction of network responses to disturbances of single or multiple parameters. Copyright © 2013 Elsevier Inc. All rights reserved.

Role of ethylene receptors during senescence and ripening in horticultural crops

PubMed Central

Agarwal, Gaurav; Choudhary, Divya; Singh, Virendra P.; Arora, Ajay

2012-01-01

The past two decades have been rewarding in terms of deciphering the ethylene signal transduction and functional validation of the ethylene receptor and downstream genes involved in the cascade. Our knowledge of ethylene receptors and its signal transduction pathway provides us a robust platform where we can think of manipulating and regulating ethylene sensitivity by the use of genetic engineering and making transgenic. This review focuses on ethylene perception, receptor mediated regulation of ethylene biosynthesis, role of ethylene receptors in flower senescence, fruit ripening and other effects induced by ethylene. The expression behavior of the receptor and downstream molecules in climacteric and non climacteric crops is also elaborated upon. Possible strategies and recent advances in altering the ethylene sensitivity of plants using ethylene receptor genes in an attempt to modulate the regulation and sensitivity to ethylene have also been discussed. Not only will these transgenic plants be a boon to post-harvest physiology and crop improvement but, it will also help us in discovering the mechanism of regulation of ethylene sensitivity. PMID:22751331

The Role of Lymphangiogenesis in Orthotopic Prostatic Tumor-Environment on Regional and Systemic Metastasis

DTIC Science & Technology

2008-01-01

expressing Renilla luciferase and VEGF-C shRNA or irrelevant firefly luciferase shRNA (Ctrl) were implanted orthotopically as before. To determine the...on metastasis in Pten knockout model (Month 10-24): a) Generate Ubc/sVEGFR-3 and Ubc/ Renilla luciferase (RL) lentiviral vectors by subcloning...progression (month 10-12) c) Monitor efficiency of Ubc/lentiviral transduction and expression in Pten (-/-) prostate using optical imaging of Renilla

The Membrane and Lipids as Integral Participants in Signal Transduction: Lipid Signal Transduction for the Non-Lipid Biochemist

ERIC Educational Resources Information Center

Eyster, Kathleen M.

2007-01-01

Reviews of signal transduction have often focused on the cascades of protein kinases and protein phosphatases and their cytoplasmic substrates that become activated in response to extracellular signals. Lipids, lipid kinases, and lipid phosphatases have not received the same amount of attention as proteins in studies of signal transduction.…

Optimization of the transductional efficiency of lentiviral vectors: effect of sera and polycations

PubMed Central

Denning, Warren; Das, Suvendu; Guo, Siqi; Xu, Jun; Kappes, John C.; Hel, Zdenek

2012-01-01

Lentiviral vectors are widely used as effective gene-delivery vehicles. Optimization of the conditions for efficient lentiviral transduction is of a high importance for a variety of research applications. Presence of positively-charged polycations reduces the electrostatic repulsion forces between a negatively-charged cell and an approaching enveloped lentiviral particle resulting in an increase in the transduction efficiency. Although a variety of polycations are commonly used to enhance the transduction with retroviruses, the relative effect of various types of polycations on the efficiency of transduction and on the potential bias in the determination of titer of lentiviral vectors is not fully understood. Here we present data suggesting that DEAE-dextran provides superior results in enhancing lentiviral transduction of most tested cell lines and primary cell cultures. Specific type and source of serum affects the efficiency of transduction of target cell populations. Non-specific binding of enhanced green fluorescent protein (EGFP)-containing membrane aggregates in the presence of DEAE-dextran does not significantly affect the determination of the titer of EGFP-expressing lentiviral vectors. In conclusion, various polycations and types of sera should be tested when optimizing lentiviral transduction of target cell populations. PMID:22407723

Optimization of the transductional efficiency of lentiviral vectors: effect of sera and polycations.

PubMed

Denning, Warren; Das, Suvendu; Guo, Siqi; Xu, Jun; Kappes, John C; Hel, Zdenek

2013-03-01

Lentiviral vectors are widely used as effective gene-delivery vehicles. Optimization of the conditions for efficient lentiviral transduction is of a high importance for a variety of research applications. Presence of positively charged polycations reduces the electrostatic repulsion forces between a negatively charged cell and an approaching enveloped lentiviral particle resulting in an increase in the transduction efficiency. Although a variety of polycations are commonly used to enhance the transduction with retroviruses, the relative effect of various types of polycations on the efficiency of transduction and on the potential bias in the determination of titer of lentiviral vectors is not fully understood. Here, we present data suggesting that DEAE-dextran provides superior results in enhancing lentiviral transduction of most tested cell lines and primary cell cultures. Specific type and source of serum affects the efficiency of transduction of target cell populations. Non-specific binding of enhanced green fluorescent protein (EGFP)-containing membrane aggregates in the presence of DEAE-dextran does not significantly affect the determination of the titer of EGFP-expressing lentiviral vectors. In conclusion, various polycations and types of sera should be tested when optimizing lentiviral transduction of target cell populations.

Enhancing Endosomal Escape of Transduced Proteins by Photochemical Internalisation

PubMed Central

Mellert, Kevin; Lamla, Markus; Scheffzek, Klaus; Wittig, Rainer; Kaufmann, Dieter

2012-01-01

Induced internalisation of functional proteins into cultured cells has become an important aspect in a rising number of in vitro and in vivo assays. The endo-lysosomal entrapment of the transduced proteins remains the major problem in all transduction protocols. In this study we compared the efficiency, cytotoxicity and protein targeting of different commercially available transduction reagents by transducing a well-studied fluorescently labelled protein (Atto488-bovine serum albumin) into cultured human sarcoma cells. The amount of internalised protein and toxicity differed between the different reagents, but the percentage of transduced cells was consistently high. Furthermore, in all protocols the signals of the transduced Atto488-BSA were predominantly punctual consistent with an endosomal localisation. To overcome the endosomal entrapment, the transduction protocols were combined with a photochemical internalisation (PCI) treatment. Using this combination revealed that an endosomal disruption is highly effective in cell penetrating peptide (CPP) mediated transduction, whereas lipid-mediated transductions lead to a lower signal spreading throughout the cytosol. No change in the signal distribution could be achieved in treatments using non-lipid polymers as a transduction reagent. Therefore, the combination of protein transduction protocols based on CPPs with the endosomolytic treatment PCI can facilitate protein transduction experiments in vitro. PMID:23285056

Enhancing endosomal escape of transduced proteins by photochemical internalisation.

PubMed

Mellert, Kevin; Lamla, Markus; Scheffzek, Klaus; Wittig, Rainer; Kaufmann, Dieter

2012-01-01

Induced internalisation of functional proteins into cultured cells has become an important aspect in a rising number of in vitro and in vivo assays. The endo-lysosomal entrapment of the transduced proteins remains the major problem in all transduction protocols. In this study we compared the efficiency, cytotoxicity and protein targeting of different commercially available transduction reagents by transducing a well-studied fluorescently labelled protein (Atto488-bovine serum albumin) into cultured human sarcoma cells. The amount of internalised protein and toxicity differed between the different reagents, but the percentage of transduced cells was consistently high. Furthermore, in all protocols the signals of the transduced Atto488-BSA were predominantly punctual consistent with an endosomal localisation. To overcome the endosomal entrapment, the transduction protocols were combined with a photochemical internalisation (PCI) treatment. Using this combination revealed that an endosomal disruption is highly effective in cell penetrating peptide (CPP) mediated transduction, whereas lipid-mediated transductions lead to a lower signal spreading throughout the cytosol. No change in the signal distribution could be achieved in treatments using non-lipid polymers as a transduction reagent. Therefore, the combination of protein transduction protocols based on CPPs with the endosomolytic treatment PCI can facilitate protein transduction experiments in vitro.

Fluid shear stress primes mouse embryonic stem cells for differentiation in a self-renewing environment via heparan sulfate proteoglycans transduction

PubMed Central

Toh, Yi-Chin; Voldman, Joel

2011-01-01

Shear stress is a ubiquitous environmental cue experienced by stem cells when they are being differentiated or expanded in perfusion cultures. However, its role in modulating self-renewing stem cell phenotypes is unclear, since shear is usually only studied in the context of cardiovascular differentiation. We used a multiplex microfluidic array, which overcomes the limitations of macroperfusion systems in shear application throughput and precision, to initiate a comprehensive, quantitative study of shear effects on self-renewing mouse embryonic stem cells (mESCs), where shear stresses varying by >1000 times (0.016–16 dyn/cm2) are applied simultaneously. When compared with static controls in the presence or absence of a saturated soluble environment (i.e., mESC-conditioned medium), we ascertained that flow-induced shear stress specifically up-regulates the epiblast marker Fgf5. Epiblast-state transition in mESCs involves heparan sulfate proteoglycans (HSPGs), which have also been shown to transduce shear stress in endothelial cells. By disrupting (with sulfation inhibitors and heparinase) and partially reconstituting (with heparin) HSPG function, we show that mESCs also mechanically sense shear stress via HSPGs to modulate Fgf5 expression. This study demonstrates that self-renewing mESCs possess the molecular machinery to sense shear stress and provides quantitative shear application benchmarks for future scalable stem cell culture systems.—Toh, Y.-C., Voldman, J. Fluid shear stress primes mouse embryonic stem cells for differentiation in a self-renewing environment via heparan sulfate proteoglycans transduction. PMID:21183594

The sensory transduction pathways in bacterial chemotaxis

NASA Technical Reports Server (NTRS)

Taylor, Barry L.

1989-01-01

Bacterial chemotaxis is a useful model for investigating in molecular detail the behavioral response of cells to changes in their environment. Peritrichously flagellated bacteria such as coli and typhimurium swim by rotating helical flagella in a counterclockwise direction. If flagellar rotation is briefly reversed, the bacteria tumble and change the direction of swimming. The bacteria continuously sample the environment and use a temporal sensing mechanism to compare the present and immediate past environments. Bacteria respond to a broad range of stimuli including changes in temperature, oxygen concentration, pH and osmotic strength. Bacteria are attracted to potential sources of nutrition such as sugars and amino acids and are repelled by other chemicals. In the methylation-dependent pathways for sensory transduction and adaptation in E. coli and S. typhimurium, chemoeffectors bind to transducing proteins that span the plasma membrane. The transducing proteins are postulated to control the rate of autophosphorylation of the CheA protein, which in turn phosphorylates the CheY protein. The phospho-CheY protein binds to the switch on the flagellar motor and is the signal for clockwise rotation of the motor. Adaptation to an attractant is achieved by increasing methylation of the transducing protein until the attractant stimulus is cancelled. Responses to oxygen and certain sugars involve methylation-independent pathways in which adaption occurs without methylation of a transducing protein. Taxis toward oxygen is mediated by the electron transport system and changes in the proton motive force. Recent studies have shown that the methylation-independent pathway converges with the methylation-dependent pathway at or before the CheA protein.

Melanin, Radiation, and Energy Transduction in Fungi.

PubMed

Casadevall, Arturo; Cordero, Radames J B; Bryan, Ruth; Nosanchuk, Joshua; Dadachova, Ekaterina

2017-03-01

Melanin pigments are found in many diverse fungal species, where they serve a variety of functions that promote fitness and cell survival. Melanotic fungi inhabit some of the most extreme habitats on earth such as the damaged nuclear reactor at Chernobyl and the highlands of Antarctica, both of which are high-radiation environments. Melanotic fungi migrate toward radioactive sources, which appear to enhance their growth. This phenomenon, combined with the known capacities of melanin to absorb a broad spectrum of electromagnetic radiation and transduce this radiation into other forms of energy, raises the possibility that melanin also functions in harvesting such energy for biological usage. The ability of melanotic fungi to harness electromagnetic radiation for physiological processes has enormous implications for biological energy flows in the biosphere and for exobiology, since it provides new mechanisms for survival in extraterrestrial conditions. Whereas some features of the way melanin-related energy transduction works can be discerned by linking various observations and circumstantial data, the mechanistic details remain to be discovered.

Pathobiology of Pneumocystis pneumonia: life cycle, cell wall and cell signal transduction.

PubMed

Skalski, Joseph H; Kottom, Theodore J; Limper, Andrew H

2015-09-01

Pneumocystis is a genus of ascomycetous fungi that are highly morbid pathogens in immunosuppressed humans and other mammals. Pneumocystis cannot easily be propagated in culture, which has greatly hindered understanding of its pathobiology. The Pneumocystis life cycle is intimately associated with its mammalian host lung environment, and life cycle progression is dependent on complex interactions with host alveolar epithelial cells and the extracellular matrix. The Pneumocystis cell wall is a varied and dynamic structure containing a dominant major surface glycoprotein, β-glucans and chitins that are important for evasion of host defenses and stimulation of the host immune system. Understanding of Pneumocystis cell signaling pathways is incomplete, but much has been deduced by comparison of the Pneumocystis genome with homologous genes and proteins in related fungi. In this mini-review, the pathobiology of Pneumocystis is reviewed, with particular focus on the life cycle, cell wall components and cell signal transduction. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Adeno-Associated Virus Type 6 (AAV6) Vectors Mediate Efficient Transduction of Airway Epithelial Cells in Mouse Lungs Compared to That of AAV2 Vectors

PubMed Central

Halbert, Christine L.; Allen, James M.; Miller, A. Dusty

2001-01-01

Although vectors derived from adeno-associated virus type 2 (AAV2) promote gene transfer and expression in many somatic tissues, studies with animal models and cultured cells show that the apical surface of airway epithelia is resistant to transduction by AAV2 vectors. Approaches to increase transduction rates include increasing the amount of vector and perturbing the integrity of the epithelia. In this study, we explored the use of vectors based on AAV6 to increase transduction rates in airways. AAV vectors were made using combinations of rep, cap, and packaged genomes from AAV2 or AAV6. The packaged genomes encoded human placental alkaline phosphatase and contained terminal repeat sequences from AAV2 or AAV6. We found that transduction efficiency was primarily dependent on the source of Cap protein, defined here as the vector pseudotype. The AAV6 and AAV2 pseudotype vectors exhibited different tropisms in tissue-cultured cells, and cell transduction by AAV6 vectors was not inhibited by heparin, nor did they compete for entry in a transduction assay, indicating that AAV6 and AAV2 capsid bind different receptors. In vivo analysis of vectors showed that AAV2 pseudotype vectors gave high transduction rates in alveolar cells but much lower rates in the airway epithelium. In contrast, the AAV6 pseudotype vectors exhibited much more efficient transduction of epithelial cells in large and small airways, showing up to 80% transduction in some airways. These results, combined with our previous results showing lower immunogenicity of AAV6 than of AAV2 vectors, indicate that AAV6 vectors may provide significant advantages over AAV2 for gene therapy of lung diseases like cystic fibrosis. PMID:11413329

Redox mechanisms in hepatic chronic wound healing and fibrogenesis

PubMed Central

Novo, Erica; Parola, Maurizio

2008-01-01

Reactive oxygen species (ROS) generated within cells or, more generally, in a tissue environment, may easily turn into a source of cell and tissue injury. Aerobic organisms have developed evolutionarily conserved mechanisms and strategies to carefully control the generation of ROS and other oxidative stress-related radical or non-radical reactive intermediates (that is, to maintain redox homeostasis), as well as to 'make use' of these molecules under physiological conditions as tools to modulate signal transduction, gene expression and cellular functional responses (that is, redox signalling). However, a derangement in redox homeostasis, resulting in sustained levels of oxidative stress and related mediators, can play a significant role in the pathogenesis of major human diseases characterized by chronic inflammation, chronic activation of wound healing and tissue fibrogenesis. This review has been designed to first offer a critical introduction to current knowledge in the field of redox research in order to introduce readers to the complexity of redox signalling and redox homeostasis. This will include ready-to-use key information and concepts on ROS, free radicals and oxidative stress-related reactive intermediates and reactions, sources of ROS in mammalian cells and tissues, antioxidant defences, redox sensors and, more generally, the major principles of redox signalling and redox-dependent transcriptional regulation of mammalian cells. This information will serve as a basis of knowledge to introduce the role of ROS and other oxidative stress-related intermediates in contributing to essential events, such as the induction of cell death, the perpetuation of chronic inflammatory responses, fibrogenesis and much more, with a major focus on hepatic chronic wound healing and liver fibrogenesis. PMID:19014652

A Neural Network Model to Learn Multiple Tasks under Dynamic Environments

NASA Astrophysics Data System (ADS)

Tsumori, Kenji; Ozawa, Seiichi

When environments are dynamically changed for agents, the knowledge acquired in an environment might be useless in future. In such dynamic environments, agents should be able to not only acquire new knowledge but also modify old knowledge in learning. However, modifying all knowledge acquired before is not efficient because the knowledge once acquired may be useful again when similar environment reappears and some knowledge can be shared among different environments. To learn efficiently in such environments, we propose a neural network model that consists of the following modules: resource allocating network, long-term & short-term memory, and environment change detector. We evaluate the model under a class of dynamic environments where multiple function approximation tasks are sequentially given. The experimental results demonstrate that the proposed model possesses stable incremental learning, accurate environmental change detection, proper association and recall of old knowledge, and efficient knowledge transfer.

Membrane penetrating peptides greatly enhance baculovirus transduction efficiency into mammalian cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Hong-Zhang; Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan, ROC; Wu, Carol P.

2011-02-11

Research highlights: {yields} Ligation of CTP with GP64 enhances baculovirus transduction into mammalian cells. {yields} Fusion of PTD with VP39 enhances baculovirus transduction into mammalian cells. {yields} CTP and PTD-carrying viruses improve the transduction of co-transduced baculoviruses. {yields} Virus entry and gene expression can be separate events in different cell types. -- Abstract: The baculovirus group of insect viruses is widely used for foreign gene introduction into mammalian cells for gene expression and protein production; however, the efficiency of baculovirus entry into mammalian cells is in general still low. In this study, two recombinant baculoviruses were engineered and their abilitymore » to improve viral entry was examined: (1) cytoplasmic transduction peptide (CTP) was fused with baculovirus envelope protein, GP64, to produce a cytoplasmic membrane penetrating baculovirus (vE-CTP); and (2) the protein transduction domain (PTD) of HIV TAT protein was fused with the baculovirus capsid protein VP39 to form a nuclear membrane penetrating baculovirus (vE-PTD). Transduction experiments showed that both viruses had better transduction efficiency than vE, a control virus that only expresses EGFP in mammalian cells. Interestingly, vE-CTP and vE-PTD were also able to improve the transduction efficiency of a co-transduced baculovirus, resulting in higher levels of gene expression. Our results have described new routes to further enhance the development of baculovirus as a tool for gene delivery into mammalian cells.« less

Disruption of Microtubules Post-Virus Entry Enhances Adeno-Associated Virus Vector Transduction

PubMed Central

Xiao, Ping-Jie; Mitchell, Angela M.; Huang, Lu; Li, Chengwen; Samulski, R. Jude

2016-01-01

Perinuclear retention of viral particles is a poorly understood phenomenon observed during many virus infections. In this study, we investigated whether perinuclear accumulation acts as a barrier to limit recombinant adeno-associated virus (rAAV) transduction. After nocodazole treatment to disrupt microtubules at microtubule-organization center (MT-MTOC) after virus entry, we observed higher rAAV transduction. To elucidate the role of MT-MTOC in rAAV infection and study its underlying mechanisms, we demonstrated that rAAV's perinuclear localization was retained by MT-MTOC with fluorescent analysis, and enhanced rAAV transduction from MT-MTOC disruption was dependent on the rAAV capsid's nuclear import signals. Interestingly, after knocking down RhoA or inhibiting its downstream effectors (ROCK and Actin), MT-MTOC disruption failed to increase rAAV transduction or nuclear entry. These data suggest that enhancement of rAAV transduction is the result of increased trafficking to the nucleus via the RhoA-ROCK-Actin pathway. Ten-fold higher rAAV transduction was also observed by disrupting MT-MTOC in brain, liver, and tumor in vivo. In summary, this study indicates that virus perinuclear accumulation at MT-MTOC is a barrier-limiting parameter for effective rAAV transduction and defines a novel defense mechanism by which host cells restrain viral invasion. PMID:26942476

Polymerase chain reaction-based detection of myc transduction in feline leukemia virus-infected cats.

PubMed

Sumi, Ryosuke; Miyake, Ariko; Endo, Taiji; Ohsato, Yoshiharu; Ngo, Minh Ha; Nishigaki, Kazuo

2018-04-01

Feline lymphomas are associated with the transduction and activation of cellular proto-oncogenes, such as c-myc, by feline leukemia virus (FeLV). We describe a polymerase chain reaction assay for detection of myc transduction usable in clinical diagnosis. The assay targets c-myc exons 2 and 3, which together result in a FeLV-specific fusion gene following c-myc transduction. When this assay was conducted on FeLV-infected feline tissues submitted for clinical diagnosis of tumors, myc transduction was detected in 14% of T-cell lymphoma/leukemias. This newly established system could become a useful diagnostic tool in veterinary medicine.

Polyploidization without mitosis improves in vivo liver transduction with lentiviral vectors.

PubMed

Pichard, Virginie; Couton, Dominique; Desdouets, Chantal; Ferry, Nicolas

2013-02-01

Lentiviral vectors are efficient gene delivery vehicles for therapeutic and research applications. In contrast to oncoretroviral vectors, they are able to infect most nonproliferating cells. In the liver, induction of cell proliferation dramatically improved hepatocyte transduction using all types of retroviral vectors. However, the precise relationship between hepatocyte division and transduction efficiency has not been determined yet. Here we compared gene transfer efficiency in the liver after in vivo injection of recombinant lentiviral or Moloney murine leukemia viral (MoMuLV) vectors in hepatectomized rats treated or not with retrorsine, an alkaloid that blocks hepatocyte division and induces megalocytosis. Partial hepatectomy alone resulted in a similar increase in hepatocyte transduction using either vector. In retrorsine-treated and partially hepatectomized rats, transduction with MoMuLV vectors dropped dramatically. In contrast, we observed that retrorsine treatment combined with partial hepatectomy increased lentiviral transduction to higher levels than hepatectomy alone. Analysis of nuclear ploidy in single cells showed that a high level of transduction was associated with polyploidization. In conclusion, endoreplication could be exploited to improve the efficiency of liver-directed lentiviral gene therapy.

Polyploidization Without Mitosis Improves In Vivo Liver Transduction With Lentiviral Vectors

PubMed Central

Couton, Dominique; Desdouets, Chantal; Ferry, Nicolas

2013-01-01

Abstract Lentiviral vectors are efficient gene delivery vehicles for therapeutic and research applications. In contrast to oncoretroviral vectors, they are able to infect most nonproliferating cells. In the liver, induction of cell proliferation dramatically improved hepatocyte transduction using all types of retroviral vectors. However, the precise relationship between hepatocyte division and transduction efficiency has not been determined yet. Here we compared gene transfer efficiency in the liver after in vivo injection of recombinant lentiviral or Moloney murine leukemia viral (MoMuLV) vectors in hepatectomized rats treated or not with retrorsine, an alkaloid that blocks hepatocyte division and induces megalocytosis. Partial hepatectomy alone resulted in a similar increase in hepatocyte transduction using either vector. In retrorsine-treated and partially hepatectomized rats, transduction with MoMuLV vectors dropped dramatically. In contrast, we observed that retrorsine treatment combined with partial hepatectomy increased lentiviral transduction to higher levels than hepatectomy alone. Analysis of nuclear ploidy in single cells showed that a high level of transduction was associated with polyploidization. In conclusion, endoreplication could be exploited to improve the efficiency of liver-directed lentiviral gene therapy. PMID:23249390

Defining a Novel Role for the Coxsackievirus and Adenovirus Receptor in Human Adenovirus Serotype 5 Transduction In Vitro in the Presence of Mouse Serum

PubMed Central

Lopez-Gordo, Estrella; Doszpoly, Andor; Duffy, Margaret R.; Coughlan, Lynda; Bradshaw, Angela C.; White, Katie M.; Denby, Laura; Nicklin, Stuart A.

2017-01-01

ABSTRACT Human adenoviral serotype 5 (HAdV-5) vectors have predominantly hepatic tropism when delivered intravascularly, resulting in immune activation and toxicity. Coagulation factor X (FX) binding to HAdV-5 mediates liver transduction and provides protection from virion neutralization in mice. FX is dispensable for liver transduction in mice lacking IgM antibodies or complement, suggesting that alternative transduction pathways exist. To identify novel factor(s) mediating HAdV-5 FX-independent entry, we investigated HAdV-5 transduction in vitro in the presence of serum from immunocompetent C57BL/6 or immunocompromised mice lacking IgM antibodies (Rag 2−/− and NOD-scid-gamma [NSG]). Sera from all three mouse strains enhanced HAdV-5 transduction of A549 cells. While inhibition of HAdV-5–FX interaction with FX-binding protein (X-bp) inhibited transduction in the presence of C57BL/6 serum, it had negligible effect on the enhanced transduction observed in the presence of Rag 2−/− or NSG serum. Rag 2−/− serum also enhanced transduction of the FX binding-deficient HAdV-5HVR5*HVR7*E451Q (AdT*). Interestingly, Rag 2−/− serum enhanced HAdV-5 transduction in a FX-independent manner in CHO-CAR and SKOV3-CAR cells (CHO or SKOV3 cells transfected to stably express human coxsackievirus and adenovirus receptor [CAR]). Additionally, blockade of CAR with soluble HAdV-5 fiber knob inhibited mouse serum-enhanced transduction in A549 cells, suggesting a potential role for CAR. Transduction of HAdV-5 KO1 and HAdV-5/F35 (CAR binding deficient) in the presence of Rag 2−/− serum was equivalent to that of HAdV-5, indicating that direct interaction between HAdV-5 and CAR is not required. These data suggest that FX may protect HAdV-5 from neutralization but has minimal contribution to HAdV-5 transduction in the presence of immunocompromised mouse serum. Alternatively, transduction occurs via an unidentified mouse serum protein capable of bridging HAdV-5 to CAR. IMPORTANCE The intravascular administration of HAdV-5 vectors can result in acute liver toxicity, transaminitis, thrombocytopenia, and injury to the vascular endothelium, illustrating challenges yet to overcome for HAdV-5-mediated systemic gene therapy. The finding that CAR and potentially an unidentified factor present in mouse serum might be important mediators of HAdV-5 transduction highlights that a better understanding of the complex biology defining the interplay between adenovirus immune recognition and cellular uptake mechanisms is still required. These findings are important to inform future optimization and development of HAdV-5-based adenoviral vectors for gene therapy. PMID:28381574

Dynamic Receptor Team Formation Can Explain the High Signal Transduction Gain in Escherichia coli

PubMed Central

Albert, Réka; Chiu, Yu-wen; Othmer, Hans G.

2004-01-01

Evolution has provided many organisms with sophisticated sensory systems that enable them to respond to signals in their environment. The response frequently involves alteration in the pattern of movement, either by directed movement, a process called taxis, or by altering the speed or frequency of turning, which is called kinesis. Chemokinesis has been most thoroughly studied in the peritrichous bacterium Escherichia coli, which has four helical flagella distributed over the cell surface, and swims by rotating them. When rotated counterclockwise the flagella coalesce into a propulsive bundle, producing a relatively straight “run,” and when rotated clockwise they fly apart, resulting in a “tumble” which reorients the cell with little translocation. A stochastic process generates the runs and tumbles, and in a chemoeffector gradient, runs that carry the cell in a favorable direction are extended. The cell senses spatial gradients as temporal changes in receptor occupancy and changes the probability of counterclockwise rotation (the bias) on a fast timescale, but adaptation returns the bias to baseline on a slow timescale, enabling the cell to detect and respond to further concentration changes. The overall structure of the signal transduction pathways is well characterized in E. coli, but important details are still not understood. Only recently has a source of gain in the signal transduction network been identified experimentally, and here we present a mathematical model based on dynamic assembly of receptor teams that can explain this observation. PMID:15111386

Dynamic receptor team formation can explain the high signal transduction gain in Escherichia coli.

PubMed

Albert, Réka; Chiu, Yu-Wen; Othmer, Hans G

2004-05-01

Evolution has provided many organisms with sophisticated sensory systems that enable them to respond to signals in their environment. The response frequently involves alteration in the pattern of movement, either by directed movement, a process called taxis, or by altering the speed or frequency of turning, which is called kinesis. Chemokinesis has been most thoroughly studied in the peritrichous bacterium Escherichia coli, which has four helical flagella distributed over the cell surface, and swims by rotating them. When rotated counterclockwise the flagella coalesce into a propulsive bundle, producing a relatively straight "run," and when rotated clockwise they fly apart, resulting in a "tumble" which reorients the cell with little translocation. A stochastic process generates the runs and tumbles, and in a chemoeffector gradient, runs that carry the cell in a favorable direction are extended. The cell senses spatial gradients as temporal changes in receptor occupancy and changes the probability of counterclockwise rotation (the bias) on a fast timescale, but adaptation returns the bias to baseline on a slow timescale, enabling the cell to detect and respond to further concentration changes. The overall structure of the signal transduction pathways is well characterized in E. coli, but important details are still not understood. Only recently has a source of gain in the signal transduction network been identified experimentally, and here we present a mathematical model based on dynamic assembly of receptor teams that can explain this observation.

Effects of calcium at toxic concentrations of cadmium in plants.

PubMed

Huang, Danlian; Gong, Xiaomin; Liu, Yunguo; Zeng, Guangming; Lai, Cui; Bashir, Hassan; Zhou, Lu; Wang, Dafei; Xu, Piao; Cheng, Min; Wan, Jia

2017-05-01

This review provides new insight that calcium plays important roles in plant growth, heavy metal accumulation and translocation, photosynthesis, oxidative damage and signal transduction under cadmium stress. Increasing heavy metal pollution problems have raised word-wide concerns. Cadmium (Cd), being a highly toxic metal, poses potential risks both to ecosystems and human health. Compared with conventional technologies, phytoremediation, being cost-efficient, highly stable and environment-friendly, is believed to be a promising green technology for Cd decontamination. However, Cd can be easily taken up by plants and may cause severe phytotoxicity to plants, thus limiting the efficiency of phytoremediation. Various researches are being done to investigate the effects of exogenous substances on the mitigation of Cd toxicity to plants. Calcium (Ca) is an essential plant macronutrient that involved in various plant physiological processes, such as plant growth and development, cell division, cytoplasmic streaming, photosynthesis and intracellular signaling transduction. Due to the chemical similarity between Ca and Cd, Ca may mediate Cd-induced physiological or metabolic changes in plants. Recent studies have shown that Ca could be used as an exogenous substance to protect plants against Cd stress by the alleviation of growth inhibition, regulation of metal uptake and translocation, improvement of photosynthesis, mitigation of oxidative damages and the control of signal transduction in the plants. The effects of Ca on toxic concentrations of Cd in plants are reviewed. This review also provides new insight that plants with enhanced Ca level have improved resistance to Cd stress.

Regulated portals of entry into the cell

NASA Astrophysics Data System (ADS)

Conner, Sean D.; Schmid, Sandra L.

2003-03-01

The plasma membrane is the interface between cells and their harsh environment. Uptake of nutrients and all communication among cells and between cells and their environment occurs through this interface. `Endocytosis' encompasses several diverse mechanisms by which cells internalize macromolecules and particles into transport vesicles derived from the plasma membrane. It controls entry into the cell and has a crucial role in development, the immune response, neurotransmission, intercellular communication, signal transduction, and cellular and organismal homeostasis. As the complexity of molecular interactions governing endocytosis are revealed, it has become increasingly clear that it is tightly coordinated and coupled with overall cell physiology and thus, must be viewed in a broader context than simple vesicular trafficking.

The physiological basics of the olfactory neuro-epithelium.

PubMed

Watelet, J B; Katotomichelakis, M; Eloy, P; Danielidis, V

2009-01-01

All living organisms can detect and identify chemical substances in their environment. The olfactory epithelium is covered by a mucus layer which is essential for the function of the olfactory neurons that are directly connected to the brain through the cribriform plate. However, little is known about the composition of this mucus in humans and its significance for the diagnosis of olfactory disorders. The olfactory epithelium consists of four primary cell types, including the olfactory receptor cells essential for odour transduction. This review examines the anatomical, histological and physiological fundamentals of olfactory mucosa. Particular attention is paid to the biochemical environment of the olfactory mucosa that regulates both peri-receptor events and several protective functions.

RDF SKETCH MAPS - KNOWLEDGE COMPLEXITY REDUCTION FOR PRECISION MEDICINE ANALYTICS.

PubMed

Thanintorn, Nattapon; Wang, Juexin; Ersoy, Ilker; Al-Taie, Zainab; Jiang, Yuexu; Wang, Duolin; Verma, Megha; Joshi, Trupti; Hammer, Richard; Xu, Dong; Shin, Dmitriy

2016-01-01

Realization of precision medicine ideas requires significant research effort to be able to spot subtle differences in complex diseases at the molecular level to develop personalized therapies. It is especially important in many cases of highly heterogeneous cancers. Precision diagnostics and therapeutics of such diseases demands interrogation of vast amounts of biological knowledge coupled with novel analytic methodologies. For instance, pathway-based approaches can shed light on the way tumorigenesis takes place in individual patient cases and pinpoint to novel drug targets. However, comprehensive analysis of hundreds of pathways and thousands of genes creates a combinatorial explosion, that is challenging for medical practitioners to handle at the point of care. Here we extend our previous work on mapping clinical omics data to curated Resource Description Framework (RDF) knowledge bases to derive influence diagrams of interrelationships of biomarker proteins, diseases and signal transduction pathways for personalized theranostics. We present RDF Sketch Maps - a computational method to reduce knowledge complexity for precision medicine analytics. The method of RDF Sketch Maps is inspired by the way a sketch artist conveys only important visual information and discards other unnecessary details. In our case, we compute and retain only so-called RDF Edges - places with highly important diagnostic and therapeutic information. To do this we utilize 35 maps of human signal transduction pathways by transforming 300 KEGG maps into highly processable RDF knowledge base. We have demonstrated potential clinical utility of RDF Sketch Maps in hematopoietic cancers, including analysis of pathways associated with Hairy Cell Leukemia (HCL) and Chronic Myeloid Leukemia (CML) where we achieved up to 20-fold reduction in the number of biological entities to be analyzed, while retaining most likely important entities. In experiments with pathways associated with HCL a generated RDF Sketch Map of the top 30% paths retained important information about signaling cascades leading to activation of proto-oncogene BRAF, which is usually associated with a different cancer, melanoma. Recent reports of successful treatments of HCL patients by the BRAF-targeted drug vemurafenib support the validity of the RDF Sketch Maps findings. We therefore believe that RDF Sketch Maps will be invaluable for hypothesis generation for precision diagnostics and therapeutics as well as drug repurposing studies.

Analysis of cellular signal transduction from an information theoretic approach.

PubMed

Uda, Shinsuke; Kuroda, Shinya

2016-03-01

Signal transduction processes the information of various cellular functions, including cell proliferation, differentiation, and death. The information for controlling cell fate is transmitted by concentrations of cellular signaling molecules. However, how much information is transmitted in signaling pathways has thus far not been investigated. Shannon's information theory paves the way to quantitatively analyze information transmission in signaling pathways. The theory has recently been applied to signal transduction, and mutual information of signal transduction has been determined to be a measure of information transmission. We review this work and provide an overview of how signal transduction transmits informational input and exerts biological output. Copyright © 2015 Elsevier Ltd. All rights reserved.

Microfluidic Transduction Harnesses Mass Transport Principles to Enhance Gene Transfer Efficiency.

PubMed

Tran, Reginald; Myers, David R; Denning, Gabriela; Shields, Jordan E; Lytle, Allison M; Alrowais, Hommood; Qiu, Yongzhi; Sakurai, Yumiko; Li, William C; Brand, Oliver; Le Doux, Joseph M; Spencer, H Trent; Doering, Christopher B; Lam, Wilbur A

2017-10-04

Ex vivo gene therapy using lentiviral vectors (LVs) is a proven approach to treat and potentially cure many hematologic disorders and malignancies but remains stymied by cumbersome, cost-prohibitive, and scale-limited production processes that cannot meet the demands of current clinical protocols for widespread clinical utilization. However, limitations in LV manufacture coupled with inefficient transduction protocols requiring significant excess amounts of vector currently limit widespread implementation. Herein, we describe a microfluidic, mass transport-based approach that overcomes the diffusion limitations of current transduction platforms to enhance LV gene transfer kinetics and efficiency. This novel ex vivo LV transduction platform is flexible in design, easy to use, scalable, and compatible with standard cell transduction reagents and LV preparations. Using hematopoietic cell lines, primary human T cells, primary hematopoietic stem and progenitor cells (HSPCs) of both murine (Sca-1 + ) and human (CD34 + ) origin, microfluidic transduction using clinically processed LVs occurs up to 5-fold faster and requires as little as one-twentieth of LV. As an in vivo validation of the microfluidic-based transduction technology, HSPC gene therapy was performed in hemophilia A mice using limiting amounts of LV. Compared to the standard static well-based transduction protocols, only animals transplanted with microfluidic-transduced cells displayed clotting levels restored to normal. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Computational identification of signalling pathways in Plasmodium falciparum.

PubMed

Oyelade, Jelili; Ewejobi, Itunu; Brors, Benedikt; Eils, Roland; Adebiyi, Ezekiel

2011-06-01

Malaria is one of the world's most common and serious diseases causing death of about 3 million people each year. Its most severe occurrence is caused by the protozoan Plasmodium falciparum. Reports have shown that the resistance of the parasite to existing drugs is increasing. Therefore, there is a huge and urgent need to discover and validate new drug or vaccine targets to enable the development of new treatments for malaria. The ability to discover these drug or vaccine targets can only be enhanced from our deep understanding of the detailed biology of the parasite, for example how cells function and how proteins organize into modules such as metabolic, regulatory and signal transduction pathways. It has been noted that the knowledge of signalling transduction pathways in Plasmodium is fundamental to aid the design of new strategies against malaria. This work uses a linear-time algorithm for finding paths in a network under modified biologically motivated constraints. We predicted several important signalling transduction pathways in Plasmodium falciparum. We have predicted a viable signalling pathway characterized in terms of the genes responsible that may be the PfPKB pathway recently elucidated in Plasmodium falciparum. We obtained from the FIKK family, a signal transduction pathway that ends up on a chloroquine resistance marker protein, which indicates that interference with FIKK proteins might reverse Plasmodium falciparum from resistant to sensitive phenotype. We also proposed a hypothesis that showed the FIKK proteins in this pathway as enabling the resistance parasite to have a mechanism for releasing chloroquine (via an efflux process). Furthermore, we also predicted a signalling pathway that may have been responsible for signalling the start of the invasion process of Red Blood Cell (RBC) by the merozoites. It has been noted that the understanding of this pathway will give insight into the parasite virulence and will facilitate rational vaccine design against merozoites invasion. And we have a host of other predicted pathways, some of which have been used in this work to predict the functionality of some proteins. Copyright © 2010 Elsevier B.V. All rights reserved.

Role of the unfolded protein response in topography-induced osteogenic differentiation in rat bone marrow mesenchymal stem cells.

PubMed

Shi, Mengqi; Song, Wen; Han, Tianxiao; Chang, Bei; Li, Guangwen; Jin, Jianfeng; Zhang, Yumei

2017-05-01

The topography of biomaterials can significantly influence the osteogenic differentiation of cells. Understanding topographical signal transduction is critical for developing biofunctional surfaces, but the current knowledge is insufficient. Recently, numerous reports have suggested that the unfolded protein response (UPR) and osteogenic differentiation are inter-linked. Therefore, we hypothesize that the UPR pathway may be involved in the topography-induced osteogenesis. In the present study, different surface topographies were fabricated on pure titanium foils and the endoplasmic reticulum (ER) stress and UPR pathway were systematically investigated. We found that ER stress and the PERK-eIF2α-ATF4 pathway were activated in a time- and topography-dependent manner. Additionally, the activation of the PERK-eIF2α-ATF4 pathway by different topographies was in line with their osteogenic induction capability. More specifically, the osteogenic differentiation could be enhanced or weakened when the PERK-eIF2α-ATF4 pathway was promoted or inhibited, respectively. Furthermore, tuning of the degree of ER stress with different concentrations of thapsigargin revealed that mild ER stress promotes osteogenic differentiation, whereas excessive ER stress inhibits osteogenic differentiation and causes apoptosis. Taken together, our findings suggest that the UPR may play a critical role in topography-induced osteogenic differentiation, which may help to provide new insights into topographical signal transduction. Suitable implant surface topography can effectively improve bioactivity and eventual bone affinity. However, the mechanism of topographical signaling transduction is unclear and criteria for designation of an appropriate implant surface topography is lacking. This study shows that the ER stress and PERK-eIF2α-ATF4 pathway were activated by micro- and micro/nano-topographies, which is corresponding to the osteogenic induction abilities of these topographies. Furthermore, we have found that mild ER stress improves osteogenic differentiation, whereas excessive ER stress inhibits osteogenic differentiation and causes apoptosis. Our findings demonstrate that the UPR plays a critical role in the topography induced osteogenic differentiation, which may help to provide new insights into the topographical signaling transduction. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Signaling in Parasitic Nematodes: Physicochemical Communication Between Host and Parasite and Endogenous Molecular Transduction Pathways Governing Worm Development and Survival.

PubMed

Lok, James B

2016-12-01

Signaling or communication between host and parasite may occur over relatively long ranges to enable host finding and acquisition by infective parasitic nematode larvae. Innate behaviors in infective larvae transmitted from the soil that enhance the likelihood of host contact, such as negative geotaxis and hypermotility, are likely mediated by mechanoreception and neuromuscular signaling. Host cues such as vibration of the substratum, elevated temperature, exhaled CO 2 , and other volatile odorants are perceived by mechanosensory and chemosensory neurons of the amphidial complex. Beyond this, the molecular systems that transduce these external cues within the worm are unknown at this time. Overall, the signal transduction mechanisms that regulate switching between dauer and continuous reproductive development in Caenorhabditis elegans , and doubtless other free-living nematodes, have provided a useful framework for testing hypotheses about how the morphogenesis and development of infective parasitic nematode larvae and the lifespan of adult parasites are regulated. In C. elegans , four major signal transduction pathways, G protein-coupled receptor signaling, insulin/insulin-like growth factor signaling, TGFβ-like signaling and steroid-nuclear hormone receptor signaling govern the switch between dauer and continuous development and regulate adult lifespan. Parasitic nematodes appear to have conserved the functions of G-protein-coupled signaling, insulin-like signaling and steroid-nuclear hormone receptor signaling to regulate larval development before and during the infective process. By contrast, TGFβ-like signaling appears to have been adapted for some other function, perhaps modulation of the host immune response. Of the three signal transduction pathways that appear to regulate development in parasitic nematodes, steroid-nuclear hormone signaling is the most straightforward to manipulate with administered small molecules and may form the basis of new chemotherapeutic strategies. Signaling between parasites and their hosts' immune systems also occurs and serves to modulate these responses to allow chronic infection and down regulate acute inflammatory responses. Knowledge of the precise nature of this signaling may form the basis of immunological interventions to protect against parasitism or related lesions and to alleviate inflammatory diseases of various etiologies.

The relationship between neurotrophic factors and CaMKII in the death and survival of retinal ganglion cells.

PubMed

Cooper, N G F; Laabich, A; Fan, W; Wang, X

2008-01-01

The scientific discourse relating to the causes and treatments for glaucoma are becoming reflective of the need to protect and preserve retinal neurons from degenerative changes, which result from the injurious environment associated with this disease. Knowledge, in particular, of the signal transduction pathways which affect death and survival of the retinal ganglion cells is critical to this discourse and to the development of a suitable neurotherapeutic strategy for this disease. The goal of this chapter is to review what is known of the chief suspects involved in initiating the cell death/survival pathways in these cells, and what still remains to be uncovered. The least controversial aspect of the subject relates to the potential role of neurotrophic factors in the protection of the retinal ganglion cells. On the other hand, the postulated triggers for signaling cell death in glaucoma remain controversial. Certainly, the restricted flow of neurotrophic factors has been cited as one possible trigger. However, the connections between glaucoma and other factors present in the retina, such as glutamate, long held to be a prospective culprit in retinal ganglion cell death are still being questioned. Whatever the outcome of this particular debate, it is clear that the downstream intersections between the cell death and survival pathways should provide important foci for future studies whose goal is to protect retinal neurons, situated as they are, in the stressful environment of a cell destroying disease. The evidence for CaMKII being one of these intersecting points is discussed.

Delivery and evaluation of recombinant adeno-associated viral vectors in the equine distal extremity for the treatment of laminitis.

PubMed

Mason, J B; Gurda, B L; Van Wettere, A; Engiles, J B; Wilson, J M; Richardson, D W

2017-01-01

Our long-term aim is to develop a gene therapy approach for the prevention of laminitis in the contralateral foot of horses with major musculoskeletal injuries and non-weightbearing lameness. The goal of this study was to develop a practical method to efficiently deliver therapeutic proteins deep within the equine foot. Randomised in vivo experiment. We used recombinant adeno-associated viral vectors (rAAVs) to deliver marker genes using regional limb perfusion through the palmar digital artery of the horse. Vector serotypes rAAV2/1, 2/8 and 2/9 all successfully transduced equine foot tissues and displayed similar levels and patterns of transduction. The regional distribution of transduction within the foot decreased with decreasing vector dose. The highest transduction values were seen in the sole and coronary regions and the lowest transduction values were detected in the dorsal hoof-wall region. The use of a surfactant-enriched vector diluent increased regional distribution of the vector and improved the transduction in the hoof-wall region. The hoof-wall region of the foot, which exhibited the lowest levels of transduction using saline as the vector diluent, displayed a dramatic increase in transduction when surfactant was included in the vector diluent (9- to 81-fold increase). In transduced tissues, no significant difference was observed between promoters (chicken β-actin vs. cytomegalovirus) for gene expression. All horses tested for vector-neutralising antibodies were positive for serotype-specific neutralising antibodies to rAAV2/5. The current experiments demonstrate that transgenes can be successfully delivered to the equine distal extremity using rAAV vectors and that serotypes 2/8, 2/9 and 2/1 can successfully transduce tissues of the equine foot. When the vector was diluted with surfactant-containing saline, the level of transduction increased dramatically. The increased level of transduction due to the addition of surfactant also improved the distribution pattern of transduction. © 2015 EVJ Ltd.

A Bioinformatics Facility for NASA

NASA Technical Reports Server (NTRS)

Schweighofer, Karl; Pohorille, Andrew

2006-01-01

Building on an existing prototype, we have fielded a facility with bioinformatics technologies that will help NASA meet its unique requirements for biological research. This facility consists of a cluster of computers capable of performing computationally intensive tasks, software tools, databases and knowledge management systems. Novel computational technologies for analyzing and integrating new biological data and already existing knowledge have been developed. With continued development and support, the facility will fulfill strategic NASA s bioinformatics needs in astrobiology and space exploration. . As a demonstration of these capabilities, we will present a detailed analysis of how spaceflight factors impact gene expression in the liver and kidney for mice flown aboard shuttle flight STS-108. We have found that many genes involved in signal transduction, cell cycle, and development respond to changes in microgravity, but that most metabolic pathways appear unchanged.

Nitric oxide: a multitasked signaling gas in plants.

PubMed

Domingos, Patricia; Prado, Ana Margarida; Wong, Aloysius; Gehring, Christoph; Feijo, Jose A

2015-04-01

Nitric oxide (NO) is a gaseous reactive oxygen species (ROS) that has evolved as a signaling hormone in many physiological processes in animals. In plants it has been demonstrated to be a crucial regulator of development, acting as a signaling molecule present at each step of the plant life cycle. NO has also been implicated as a signal in biotic and abiotic responses of plants to the environment. Remarkably, despite this plethora of effects and functional relationships, the fundamental knowledge of NO production, sensing, and transduction in plants remains largely unknown or inadequately characterized. In this review we cover the current understanding of NO production, perception, and action in different physiological scenarios. We especially address the issues of enzymatic and chemical generation of NO in plants, NO sensing and downstream signaling, namely the putative cGMP and Ca(2+) pathways, ion-channel activity modulation, gene expression regulation, and the interface with other ROS, which can have a profound effect on both NO accumulation and function. We also focus on the importance of NO in cell-cell communication during developmental processes and sexual reproduction, namely in pollen tube guidance and embryo sac fertilization, pathogen defense, and responses to abiotic stress. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

Life sciences and space research 24 (4): Planetary biology and origins of life; Topical Meeting of the COSPAR Interdisciplinary Scientific Commission F (Meeting F3) of the COSPAR Plenary Meeting, 29th, Washington, DC, Aug. 28-Sep. 5, 1992

NASA Technical Reports Server (NTRS)

Greenberg, J. M. (Editor); Oro, J. (Editor); Brack, A. (Editor); Devincenzi, D. L. (Editor); Banin, A. (Editor); Friedmann, E. I. (Editor); Rummel, J. D. (Editor); Raulin, F. (Editor); Mckay, C. P. (Editor); Baltscheffsky, H. (Editor)

1995-01-01

The proceedings include sessions on extraterrestrial organic chemistry and the origins of life; life on Mars: past, present and future; planetary protection of Mars missions; chemical evolution on Titan; origins and early evolution of biological (a) energy transduction and membranes (b) information and catalysis; and carbon chemistry and isotopic fractionations in astrophysical environments.

Transduction between worlds: using virtual and mixed reality for earth and planetary science

NASA Astrophysics Data System (ADS)

Hedley, N.; Lochhead, I.; Aagesen, S.; Lonergan, C. D.; Benoy, N.

2017-12-01

Virtual reality (VR) and augmented reality (AR) have the potential to transform the way we visualize multidimensional geospatial datasets in support of geoscience research, exploration and analysis. The beauty of virtual environments is that they can be built at any scale, users can view them at many levels of abstraction, move through them in unconventional ways, and experience spatial phenomena as if they had superpowers. Similarly, augmented reality allows you to bring the power of virtual 3D data visualizations into everyday spaces. Spliced together, these interface technologies hold incredible potential to support 21st-century geoscience. In my ongoing research, my team and I have made significant advances to connect data and virtual simulations with real geographic spaces, using virtual environments, geospatial augmented reality and mixed reality. These research efforts have yielded new capabilities to connect users with spatial data and phenomena. These innovations include: geospatial x-ray vision; flexible mixed reality; augmented 3D GIS; situated augmented reality 3D simulations of tsunamis and other phenomena interacting with real geomorphology; augmented visual analytics; and immersive GIS. These new modalities redefine the ways in which we can connect digital spaces of spatial analysis, simulation and geovisualization, with geographic spaces of data collection, fieldwork, interpretation and communication. In a way, we are talking about transduction between real and virtual worlds. Taking a mixed reality approach to this, we can link real and virtual worlds. This paper presents a selection of our 3D geovisual interface projects in terrestrial, coastal, underwater and other environments. Using rigorous applied geoscience data, analyses and simulations, our research aims to transform the novelty of virtual and augmented reality interface technologies into game-changing mixed reality geoscience.

Modeling the infection dynamics of bacteriophages in enteric Escherichia coli: estimating the contribution of transduction to antimicrobial gene spread.

PubMed

Volkova, Victoriya V; Lu, Zhao; Besser, Thomas; Gröhn, Yrjö T

2014-07-01

Animal-associated bacterial communities are infected by bacteriophages, although the dynamics of these infections are poorly understood. Transduction by bacteriophages may contribute to transfer of antimicrobial resistance genes, but the relative importance of transduction among other gene transfer mechanisms is unknown. We therefore developed a candidate deterministic mathematical model of the infection dynamics of enteric coliphages in commensal Escherichia coli in the large intestine of cattle. We assumed the phages were associated with the intestine and were predominantly temperate. Model simulations demonstrated how, given the bacterial ecology and infection dynamics, most (>90%) commensal enteric E. coli bacteria may become lysogens of enteric coliphages during intestinal transit. Using the model and the most liberal assumptions about transduction efficiency and resistance gene frequency, we approximated the upper numerical limits ("worst-case scenario") of gene transfer through specialized and generalized transduction in E. coli by enteric coliphages when the transduced genetic segment is picked at random. The estimates were consistent with a relatively small contribution of transduction to lateral gene spread; for example, generalized transduction delivered the chromosomal resistance gene to up to 8 E. coli bacteria/hour within the population of 1.47 × 10(8) E. coli bacteria/liter luminal contents. In comparison, the plasmidic blaCMY-2 gene carried by ~2% of enteric E. coli was transferred by conjugation at a rate at least 1.4 × 10(3) times greater than our generalized transduction estimate. The estimated numbers of transductants varied nonlinearly depending on the ecology of bacteria available for phages to infect, that is, on the assumed rates of turnover and replication of enteric E. coli. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Modeling the Infection Dynamics of Bacteriophages in Enteric Escherichia coli: Estimating the Contribution of Transduction to Antimicrobial Gene Spread

PubMed Central

Lu, Zhao; Besser, Thomas; Gröhn, Yrjö T.

2014-01-01

Animal-associated bacterial communities are infected by bacteriophages, although the dynamics of these infections are poorly understood. Transduction by bacteriophages may contribute to transfer of antimicrobial resistance genes, but the relative importance of transduction among other gene transfer mechanisms is unknown. We therefore developed a candidate deterministic mathematical model of the infection dynamics of enteric coliphages in commensal Escherichia coli in the large intestine of cattle. We assumed the phages were associated with the intestine and were predominantly temperate. Model simulations demonstrated how, given the bacterial ecology and infection dynamics, most (>90%) commensal enteric E. coli bacteria may become lysogens of enteric coliphages during intestinal transit. Using the model and the most liberal assumptions about transduction efficiency and resistance gene frequency, we approximated the upper numerical limits (“worst-case scenario”) of gene transfer through specialized and generalized transduction in E. coli by enteric coliphages when the transduced genetic segment is picked at random. The estimates were consistent with a relatively small contribution of transduction to lateral gene spread; for example, generalized transduction delivered the chromosomal resistance gene to up to 8 E. coli bacteria/hour within the population of 1.47 × 108 E. coli bacteria/liter luminal contents. In comparison, the plasmidic blaCMY-2 gene carried by ∼2% of enteric E. coli was transferred by conjugation at a rate at least 1.4 × 103 times greater than our generalized transduction estimate. The estimated numbers of transductants varied nonlinearly depending on the ecology of bacteria available for phages to infect, that is, on the assumed rates of turnover and replication of enteric E. coli. PMID:24814786

Postentry Processing of Recombinant Adeno-Associated Virus Type 1 and Transduction of the Ferret Lung Are Altered by a Factor in Airway Secretions

PubMed Central

Yan, Ziying; Sun, Xingshen; Evans, Idil A.; Tyler, Scott R.; Song, Yi; Liu, Xiaoming; Sui, Hongshu

2013-01-01

Abstract We recently created a cystic fibrosis ferret model that acquires neonatal lung infection. To develop lung gene therapies for this model, we evaluated recombinant adeno-associated virus (rAAV)-mediated gene transfer to the neonatal ferret lung. Unlike in vitro ferret airway epithelial (FAE) cells, in vivo infection of the ferret lung with rAAV1 required proteasome inhibitors to achieve efficient airway transduction. We hypothesized that differences in transduction between these two systems were because of an in vivo secreted factor that alter the transduction biology of rAAV1. Indeed, treatment of rAAV1 with ferret airway secretory fluid (ASF) strongly inhibited rAAV1, but not rAAV2, transduction of primary FAE and HeLa cells. Properties of the ASF inhibitory factor included a strong affinity for the AAV1 capsid, heat-stability, negative charge, and sensitivity to endoproteinase Glu-C. ASF-treated rAAV1 dramatically inhibited apical transduction of FAE ALI cultures (512-fold), while only reducing viral entry by 55-fold, suggesting that postentry processing of virus was influenced by the inhibitor factor. Proteasome inhibitors rescued transduction in the presence of ASF (∼1600-fold) without effecting virus internalization, while proteasome inhibitors only enhanced transduction 45-fold in the absence of ASF. These findings demonstrate that a factor in lung secretions can influence intracellular processing of rAAV1 in a proteasome-dependent fashion. PMID:23948055

Postentry processing of recombinant adeno-associated virus type 1 and transduction of the ferret lung are altered by a factor in airway secretions.

PubMed

Yan, Ziying; Sun, Xingshen; Evans, Idil A; Tyler, Scott R; Song, Yi; Liu, Xiaoming; Sui, Hongshu; Engelhardt, John F

2013-09-01

We recently created a cystic fibrosis ferret model that acquires neonatal lung infection. To develop lung gene therapies for this model, we evaluated recombinant adeno-associated virus (rAAV)-mediated gene transfer to the neonatal ferret lung. Unlike in vitro ferret airway epithelial (FAE) cells, in vivo infection of the ferret lung with rAAV1 required proteasome inhibitors to achieve efficient airway transduction. We hypothesized that differences in transduction between these two systems were because of an in vivo secreted factor that alter the transduction biology of rAAV1. Indeed, treatment of rAAV1 with ferret airway secretory fluid (ASF) strongly inhibited rAAV1, but not rAAV2, transduction of primary FAE and HeLa cells. Properties of the ASF inhibitory factor included a strong affinity for the AAV1 capsid, heat-stability, negative charge, and sensitivity to endoproteinase Glu-C. ASF-treated rAAV1 dramatically inhibited apical transduction of FAE ALI cultures (512-fold), while only reducing viral entry by 55-fold, suggesting that postentry processing of virus was influenced by the inhibitor factor. Proteasome inhibitors rescued transduction in the presence of ASF (~1600-fold) without effecting virus internalization, while proteasome inhibitors only enhanced transduction 45-fold in the absence of ASF. These findings demonstrate that a factor in lung secretions can influence intracellular processing of rAAV1 in a proteasome-dependent fashion.

Painful stimulation and transient blocking of nerve transduction due to local anesthesia evoke perceptual distortions of the face in healthy volunteers.

PubMed

Skyt, Ina; Dagsdóttir, Lilja; Vase, Lene; Baad-Hansen, Lene; Castrillon, Eduardo; Roepstorff, Andreas; Jensen, Troels Staehelin; Svensson, Peter

2015-04-01

Anecdotally, orofacial pain patients sometimes report that the painful face area feels "swollen." Because there are no clinical signs of swelling, such illusions may represent perceptual distortions. In this study, we examine whether nociceptive stimulation can lead to perceptual distortion of the face in a way similar to that of local anesthesia. Sixteen healthy participants received injections of .4 mL hypertonic saline to induce short-term nociceptive stimulation, .4 mL mepivacaine (local anesthetic) to transiently block nerve transduction, and .4 mL isotonic saline as a control condition. Injections were administered in both the infraorbital and the mental nerve regions. Perceptual distortions were conceptualized as perceived changes in magnitude of the injected areas and the lips, and they were measured using 1) a verbal subjective rating scale and 2) a warping procedure. Prior to the study, participants filled in several psychological questionnaires. This study shows that both nociceptive stimulation (P < .05) and transient blocking of nerve transduction (P < .05) can lead to perceptual distortion of the face. A test-retest experiment including 9 new healthy subjects supported the results. Perceptual distortions were positively correlated with the psychological variable of dissociation in several conditions (P < .05). Perceptual distortions may therefore be influenced by somatosensory changes and psychological mechanisms. Knowledge of the factors that influence the perception of the face is important to understand the possible implications of perceptual distortions in orofacial pain disorders (and possibly other chronic pain states). Such information may ultimately open up new avenues of treatment for persistent orofacial pain. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

Sel1-like repeat proteins in signal transduction.

PubMed

Mittl, Peer R E; Schneider-Brachert, Wulf

2007-01-01

Solenoid proteins, which are distinguished from general globular proteins by their modular architectures, are frequently involved in signal transduction pathways. Proteins from the tetratricopeptide repeat (TPR) and Sel1-like repeat (SLR) families share similar alpha-helical conformations but different consensus sequence lengths and superhelical topologies. Both families are characterized by low sequence similarity levels, rendering the identification of functional homologous difficult. Therefore current knowledge of the molecular and cellular functions of the SLR proteins Sel1, Hrd3, Chs4, Nif1, PodJ, ExoR, AlgK, HcpA, Hsp12, EnhC, LpnE, MotX, and MerG has been reviewed. Although SLR proteins possess different cellular functions they all seem to serve as adaptor proteins for the assembly of macromolecular complexes. Sel1, Hrd3, Hsp12 and LpnE are activated under cellular stress. The eukaryotic Sel1 and Hrd3 proteins are involved in the ER-associated protein degradation, whereas the bacterial LpnE, EnhC, HcpA, ExoR, and AlgK proteins mediate the interactions between bacterial and eukaryotic host cells. LpnE and EnhC are responsible for the entry of L. pneumophila into epithelial cells and macrophages. ExoR from the symbiotic microorganism S. melioti and AlgK from the pathogen P. aeruginosa regulate exopolysaccaride synthesis. Nif1 and Chs4 from yeast are responsible for the regulation of mitosis and septum formation during cell division, respectively, and PodJ guides the cellular differentiation during the cell cycle of the bacterium C. crescentus. Taken together the SLR motif establishes a link between signal transduction pathways from eukaryotes and bacteria. The SLR motif is so far absent from archaea. Therefore the SLR could have developed in the last common ancestor between eukaryotes and bacteria.

SO 2 Phototriggered Crystalline Nanomechanical Transduction of Aromatic Rotors in Tosylates: Rationalization via Photocrystallography of [Ru(NH 3 ) 4 SO 2 X]tosylate 2 (X = pyridine, 3-Cl-pyridine, 4-Cl-pyridine)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sylvester, Sven O.; Cole, Jacqueline M.; Waddell, Paul G.

2014-07-24

Thermally-reversible solid-state linkage SO2 photoisomers of three complexes in the [Ru(NH3)4SO2X]tosylate2 family are captured in their metastable states using photocrystallography, where X = pyridine (1), 3-Cl-pyridine (2) and 4-Cl-pyridine (3). This photoisomerism only exists in the single-crystal form; accordingly, the nature of the crystalline environment surrounding the photo-active species controls its properties. In particular, the structural role of the tosylate anion needs to be understood against possible chemical influences due to varying the trans ligand, X. The photo-excited geometries, photoconversion levels and thermal stabilities of the photoisomers that form in 1-3 are therefore studied. 1 and 2 yield two photo-isomersmore » at 100 K: the O-bound end-on n1-SO2 Page 1 of 32 ACS Paragon Plus Environment The Journal of Physical Chemistry (MS1) configuration and the side-bound n2-SO2 (MS2), while 3 only exhibits the more thermally stable MS2 geometry. The decay kinetics of the MS2 geometry for 1-3 demonstrate that the greater the free volume of the GS SO2 ligand for a given counterion, the greater the MS2 thermal stability. Furthermore, a rationalization is sought for the SO2 phototriggered molecular rotation of the phenyl ring in the tosylate anion; this is selectively observed in 2, manifesting as nanomechanical molecular transduction. This molecular transduction was not observed in 1, despite the presence of the MS1 geometry due to the close intermolecular interactions between the MS1 SO2 and the neighbouring tosylate ion. The decay of this anionic molecular rotor in 2, however, follows a non-traditional decay pathway, as determined by time-resolved crystallographic analysis; this contrasts with the well-behaved first-order kinetic decay of its MS1 SO2 phototrigger.« less

Molecular and genetic characterization of osmosensing and signal transduction in the nematode Caenorhabditis elegans.

PubMed

Choe, Keith P; Strange, Kevin

2007-11-01

Osmotic homeostasis is a fundamental requirement for life. In general, the effector mechanisms that mediate cellular and extracellular osmoregulation in animals are reasonably well defined. However, at the molecular level, little is known about how animals detect osmotic and ionic perturbations and transduce them into regulatory responses. The nematode Caenorhabditis elegans provides numerous powerful experimental advantages for defining the genes and integrated gene networks that underlie basic biological processes. These advantages include a fully sequenced and well-annotated genome, forward and reverse genetic and molecular tractability, and a relatively simple anatomy. C. elegans normally inhabits soil environments where it is exposed to repeated osmotic stress. In the laboratory, nematodes readily acclimate to and recover from extremes of hypertonicity. We review recent progress in defining the molecular mechanisms that underlie osmosensing and associated signal transduction in C. elegans. Some of these mechanisms are now known to be highly conserved. Therefore, studies of osmosensing in nematodes have provided, and will undoubtedly continue to provide, new insights into similar processes in more complex organisms including mammals.

Bacterial hybrid histidine kinases in plant-bacteria interactions.

PubMed

Borland, Stéphanie; Prigent-Combaret, Claire; Wisniewski-Dyé, Florence

2016-10-01

Two-component signal transduction systems are essential for many bacteria to maintain homeostasis and adapt to environmental changes. Two-component signal transduction systems typically involve a membrane-bound histidine kinase that senses stimuli, autophosphorylates in the transmitter region and then transfers the phosphoryl group to the receiver domain of a cytoplasmic response regulator that mediates appropriate changes in bacterial physiology. Although usually found on distinct proteins, the transmitter and receiver modules are sometimes fused into a so-called hybrid histidine kinase (HyHK). Such structure results in multiple phosphate transfers that are believed to provide extra-fine-tuning mechanisms and more regulatory checkpoints than classical phosphotransfers. HyHK-based regulation may be crucial for finely tuning gene expression in a heterogeneous environment such as the rhizosphere, where intricate plant-bacteria interactions occur. In this review, we focus on roles fulfilled by bacterial HyHKs in plant-associated bacteria, providing recent findings on the mechanistic of their signalling properties. Recent insights into understanding additive regulatory properties fulfilled by the tethered receiver domain of HyHKs are also addressed.

Oxygen-Dependent Cell-to-Cell Variability in the Output of the Escherichia coli Tor Phosphorelay.

PubMed

Roggiani, Manuela; Goulian, Mark

2015-06-15

Escherichia coli senses and responds to trimethylamine-N-oxide (TMAO) in the environment through the TorT-TorS-TorR signal transduction system. The periplasmic protein TorT binds TMAO and stimulates the hybrid kinase TorS to phosphorylate the response regulator TorR through a phosphorelay. Phosphorylated TorR, in turn, activates transcription of the torCAD operon, which encodes the proteins required for anaerobic respiration via reduction of TMAO to trimethylamine. Interestingly, E. coli respires TMAO in both the presence and absence of oxygen, a behavior that is markedly different from the utilization of other alternative electron acceptors by this bacterium. Here we describe an unusual form of regulation by oxygen for this system. While the average level of torCAD transcription is the same for aerobic and anaerobic cultures containing TMAO, the behavior across the population of cells is strikingly different under the two growth conditions. Cellular levels of torCAD transcription in aerobic cultures are highly heterogeneous, in contrast to the relatively homogeneous distribution in anaerobic cultures. Thus, oxygen regulates the variance of the output but not the mean for the Tor system. We further show that this oxygen-dependent variability stems from the phosphorelay. Trimethylamine-N-oxide (TMAO) is utilized by numerous bacteria as an electron acceptor for anaerobic respiration. In E. coli, expression of the proteins required for TMAO respiration is tightly regulated by a signal transduction system that is activated by TMAO. Curiously, although oxygen is the energetically preferred electron acceptor, TMAO is respired even in the presence of oxygen. Here we describe an interesting and unexpected form of regulation for this system in which oxygen produces highly variable expression of the TMAO utilization proteins across a population of cells without affecting the mean expression of these proteins. To our knowledge, this is the first reported example of a stimulus regulating the variance but not the mean output of a signaling system. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

A model framework for actuation and sensing of ionic polymer-metal composites: prospective on frequency and shear response through simulation tools

NASA Astrophysics Data System (ADS)

Stalbaum, Tyler; Shen, Qi; Kim, Kwang J.

2017-04-01

Ionic polymer-metal composite (IPMC) is a promising material for soft-robotic actuator and sensor applications. This material system offers large deformation response for low input voltage and has an aptitude for operation in hydrated environments. Researchers have been developing IPMC actuators and sensors for applications with examples of self-sensing actuators, artificial fish fins and biomimicry of other aquatic lifeforms, and in medical operations such as in guided catheter devices. IPMCs have been developed in a range of geometric configurations, with tube or cylindrical and flat-plate rectangular as the most common shapes. Several mathematical and physics-based models have been developed for describing the transduction effects of IPMCs. In this work, the underlying theories of electromechanical and mechanoelectrical transduction in IPMCs are discussed, and simulated results of frequency response and shear response are presented. A model backbone is utilized which is primarily based on ion-transport and charge dynamics within the polymer membrane. The electromechanical model, that is with an IPMC as an actuator, is caused when an electric field is applied across the membrane causing ionic migration and swelling in the polymer membrane, which is based on the Poisson-Nernst-Planck equations and solid mechanics models. The mechanoelectric model is similar in underlying physics; however, the primary mechanisms of transduction are of different significance, where anion concentrations are as important as cations. COMSOL Multiphysics is utilized for simulations. Example applications of the modeling framework are presented. The simulated results provide additional support for the underlying physics theories discussed.

Root gravitropism: an experimental tool to investigate basic cellular and molecular processes underlying mechanosensing and signal transmission in plants

NASA Technical Reports Server (NTRS)

Boonsirichai, K.; Guan, C.; Chen, R.; Masson, P. H.

2002-01-01

The ability of plant organs to use gravity as a guide for growth, named gravitropism, has been recognized for over two centuries. This growth response to the environment contributes significantly to the upward growth of shoots and the downward growth of roots commonly observed throughout the plant kingdom. Root gravitropism has received a great deal of attention because there is a physical separation between the primary site for gravity sensing, located in the root cap, and the site of differential growth response, located in the elongation zones (EZs). Hence, this system allows identification and characterization of different phases of gravitropism, including gravity perception, signal transduction, signal transmission, and curvature response. Recent studies support some aspects of an old model for gravity sensing, which postulates that root-cap columellar amyloplasts constitute the susceptors for gravity perception. Such studies have also allowed the identification of several molecules that appear to function as second messengers in gravity signal transduction and of potential signal transducers. Auxin has been implicated as a probable component of the signal that carries the gravitropic information between the gravity-sensing cap and the gravity-responding EZs. This has allowed the identification and characterization of important molecular processes underlying auxin transport and response in plants. New molecular models can be elaborated to explain how the gravity signal transduction pathway might regulate the polarity of auxin transport in roots. Further studies are required to test these models, as well as to study the molecular mechanisms underlying a poorly characterized phase of gravitropism that is independent of an auxin gradient.

Intracellular Electric Field and pH Optimize Protein Localization and Movement

PubMed Central

Cunningham, Jessica; Estrella, Veronica; Lloyd, Mark; Gillies, Robert; Frieden, B. Roy; Gatenby, Robert

2012-01-01

Mammalian cell function requires timely and accurate transmission of information from the cell membrane (CM) to the nucleus (N). These pathways have been intensively investigated and many critical components and interactions have been identified. However, the physical forces that control movement of these proteins have received scant attention. Thus, transduction pathways are typically presented schematically with little regard to spatial constraints that might affect the underlying dynamics necessary for protein-protein interactions and molecular movement from the CM to the N. We propose messenger protein localization and movements are highly regulated and governed by Coulomb interactions between: 1. A recently discovered, radially directed E-field from the NM into the CM and 2. Net protein charge determined by its isoelectric point, phosphorylation state, and the cytosolic pH. These interactions, which are widely applied in elecrophoresis, provide a previously unknown mechanism for localization of messenger proteins within the cytoplasm as well as rapid shuttling between the CM and N. Here we show these dynamics optimize the speed, accuracy and efficiency of transduction pathways even allowing measurement of the location and timing of ligand binding at the CM –previously unknown components of intracellular information flow that are, nevertheless, likely necessary for detecting spatial gradients and temporal fluctuations in ligand concentrations within the environment. The model has been applied to the RAF-MEK-ERK pathway and scaffolding protein KSR1 using computer simulations and in-vitro experiments. The computer simulations predicted distinct distributions of phosphorylated and unphosphorylated components of this transduction pathway which were experimentally confirmed in normal breast epithelial cells (HMEC). PMID:22623963

Bacteriophages Isolated from Chicken Meat and the Horizontal Transfer of Antimicrobial Resistance Genes

PubMed Central

Shousha, Amira; Awaiwanont, Nattakarn; Sofka, Dmitrij; Smulders, Frans J. M.; Paulsen, Peter; Szostak, Michael P.; Humphrey, Tom

2015-01-01

Antimicrobial resistance in microbes poses a global and increasing threat to public health. The horizontal transfer of antimicrobial resistance genes was thought to be due largely to conjugative plasmids or transposons, with only a minor part being played by transduction through bacteriophages. However, whole-genome sequencing has recently shown that the latter mechanism could be highly important in the exchange of antimicrobial resistance genes between microorganisms and environments. The transfer of antimicrobial resistance genes by phages could underlie the origin of resistant bacteria found in food. We show that chicken meat carries a number of phages capable of transferring antimicrobial resistance. Of 243 phages randomly isolated from chicken meat, about a quarter (24.7%) were able to transduce resistance to one or more of the five antimicrobials tested into Escherichia coli ATCC 13706 (DSM 12242). Resistance to kanamycin was transduced the most often, followed by that to chloramphenicol, with four phages transducing tetracycline resistance and three transducing ampicillin resistance. Phages able to transduce antimicrobial resistance were isolated from 44% of the samples of chicken meat that we tested. The statistically significant (P = 0.01) relationship between the presence of phages transducing kanamycin resistance and E. coli isolates resistant to this antibiotic suggests that transduction may be an important mechanism for transferring kanamycin resistance to E. coli. It appears that the transduction of resistance to certain antimicrobials, e.g., kanamycin, not only is widely distributed in E. coli isolates found on meat but also could represent a major mechanism for resistance transfer. The result is of high importance for animal and human health. PMID:25934615

Aspects of Plant Intelligence

PubMed Central

TREWAVAS, ANTHONY

2003-01-01

Intelligence is not a term commonly used when plants are discussed. However, I believe that this is an omission based not on a true assessment of the ability of plants to compute complex aspects of their environment, but solely a reflection of a sessile lifestyle. This article, which is admittedly controversial, attempts to raise many issues that surround this area. To commence use of the term intelligence with regard to plant behaviour will lead to a better understanding of the complexity of plant signal transduction and the discrimination and sensitivity with which plants construct images of their environment, and raises critical questions concerning how plants compute responses at the whole‐plant level. Approaches to investigating learning and memory in plants will also be considered. PMID:12740212

IC Post-Doctoral Fellowship Abstract and Bio.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lacey, Randy

2016-11-01

Whole cell biosensors (WCBs) utilize an organism’s natural ability to sense and respond to the environment. Through implementation of two different protein engineering methods, I seek to develop a WCB for the detection of important chemical signatures in the environment. I will reengineer the ligand binding profile of proteins known to alter transcription of genes, and I will engineer signal transduction in proteins already known to bind relevant compounds. In both cases, detection of compounds of interest will lead to the production of a measurable fluorescent signal within the organism. These approaches will provide the groundwork for the development ofmore » novel chemical sensing technologies that provide a cheap and efficient alternative to traditional methods for detection of compounds.« less

Report of an Army Workshop on Convergence Forecasting: Mechanochemical Transduction

DTIC Science & Technology

2012-07-01

Breakout Session 1, Group 1.........................................................................10  Figure 3. Potential Ultrasound -Mediated...Capabilities in Mechanochemical Transduction ..........10  Figure 4. Factors that Limit Potential Ultrasound -Mediated Mechanochemical Transduction... ultrasound as a mechanism to induce mechanochemical reactions. If ultrasound is to be used to provide the mechanical energy for subsequent chemical

SPINDLY, a tetratricopeptide repeat protein involved in gibberellin signal transduction in Arabidopsis.

PubMed Central

Jacobsen, S E; Binkowski, K A; Olszewski, N E

1996-01-01

Gibberellins (GAs) are a major class of plant hormones that control many developmental processes, including seed development and germination, flower and fruit development, and flowering time. Genetic studies with Arabidopsis thaliana have identified two genes involved in GA perception or signal transduction. A semidominant mutation at the GIBBERELLIN INSENSITIVE (GAI) locus results in plants resembling GA-deficient mutants but exhibiting reduced sensitivity to GA. Recessive mutations at the SPINDLY (SPY) locus cause a phenotype that is consistent with constitutive activation of GA signal transduction. Here we show that a strong allele of spy is completely epistatic to gai, indicating that SPY acts downstream of GAI. We have cloned the SPY gene and shown that it encodes a new type of signal transduction protein, which contains a tetratricopeptide repeat region, likely serving as a protein interaction domain, and a novel C-terminal region. Mutations in both domains increase GA signal transduction. The presence of a similar gene in Caenorhabditis elegans suggests that SPY represents a class of signal transduction proteins that is present throughout the eukaryotes. Images Fig. 1 Fig. 2 Fig. 3 PMID:8799194

Magnetic nanoparticles for efficient cell transduction with Semliki Forest virus.

PubMed

Kurena, Baiba; Vežāne, Aleksandra; Skrastiņa, Dace; Trofimova, Olga; Zajakina, Anna

2017-07-01

Semliki Forest virus (SFV) is a potential cancer gene therapy vector capable of providing high and transient expression of heterologous proteins in mammalian cells. However, SFV has shown suboptimal transduction levels in several cancer cell types as well as wide biodistribution of SFV has been observed after in vivo applications. Magnetic nanoparticles (MNPs) have been shown to increase cell transduction with several viral vectors in vitro under an external magnetic field and enhance magnetically guided viral vector delivery. Here, we examined a panel of MNPs for enhanced cancer cell transduction with SFV vector. Magneto-transduction using positively charged MNPs increased Semliki Forest virus transduction in TS/A mouse mammary carcinoma cells in vitro in the presence of fetal bovine serum. Positively charged MNPs efficiently captured SFV particles independently of capturing medium, and MNPs-SFV complexes were successfully separated from suspension by magnetic precipitation. These results reveal the potential application of MNPs for enhanced gene delivery by SFV vector as well as proposes magnetic precipitation for efficient concentration of SFV particles from different media. Copyright © 2017 Elsevier B.V. All rights reserved.

Mobile DNA in cancer. Extensive transduction of nonrepetitive DNA mediated by L1 retrotransposition in cancer genomes.

PubMed

Tubio, Jose M C; Li, Yilong; Ju, Young Seok; Martincorena, Inigo; Cooke, Susanna L; Tojo, Marta; Gundem, Gunes; Pipinikas, Christodoulos P; Zamora, Jorge; Raine, Keiran; Menzies, Andrew; Roman-Garcia, Pablo; Fullam, Anthony; Gerstung, Moritz; Shlien, Adam; Tarpey, Patrick S; Papaemmanuil, Elli; Knappskog, Stian; Van Loo, Peter; Ramakrishna, Manasa; Davies, Helen R; Marshall, John; Wedge, David C; Teague, Jon W; Butler, Adam P; Nik-Zainal, Serena; Alexandrov, Ludmil; Behjati, Sam; Yates, Lucy R; Bolli, Niccolo; Mudie, Laura; Hardy, Claire; Martin, Sancha; McLaren, Stuart; O'Meara, Sarah; Anderson, Elizabeth; Maddison, Mark; Gamble, Stephen; Foster, Christopher; Warren, Anne Y; Whitaker, Hayley; Brewer, Daniel; Eeles, Rosalind; Cooper, Colin; Neal, David; Lynch, Andy G; Visakorpi, Tapio; Isaacs, William B; Veer, Laura Van't; Caldas, Carlos; Desmedt, Christine; Sotiriou, Christos; Aparicio, Sam; Foekens, John A; Eyfjörd, Jórunn Erla; Lakhani, Sunil R; Thomas, Gilles; Myklebost, Ola; Span, Paul N; Børresen-Dale, Anne-Lise; Richardson, Andrea L; Van de Vijver, Marc; Vincent-Salomon, Anne; Van den Eynden, Gert G; Flanagan, Adrienne M; Futreal, P Andrew; Janes, Sam M; Bova, G Steven; Stratton, Michael R; McDermott, Ultan; Campbell, Peter J

2014-08-01

Long interspersed nuclear element-1 (L1) retrotransposons are mobile repetitive elements that are abundant in the human genome. L1 elements propagate through RNA intermediates. In the germ line, neighboring, nonrepetitive sequences are occasionally mobilized by the L1 machinery, a process called 3' transduction. Because 3' transductions are potentially mutagenic, we explored the extent to which they occur somatically during tumorigenesis. Studying cancer genomes from 244 patients, we found that tumors from 53% of the patients had somatic retrotranspositions, of which 24% were 3' transductions. Fingerprinting of donor L1s revealed that a handful of source L1 elements in a tumor can spawn from tens to hundreds of 3' transductions, which can themselves seed further retrotranspositions. The activity of individual L1 elements fluctuated during tumor evolution and correlated with L1 promoter hypomethylation. The 3' transductions disseminated genes, exons, and regulatory elements to new locations, most often to heterochromatic regions of the genome. Copyright © 2014, American Association for the Advancement of Science.

Phage-mediated horizontal gene transfer of both prophage and heterologous DNA by ϕBB-1, a bacteriophage of Borrelia burgdorferi.

PubMed

Eggers, Christian H; Gray, Carlie M; Preisig, Alexander M; Glenn, Danielle M; Pereira, Jessica; Ayers, Ryan W; Alshahrani, Mohammad; Acabbo, Christopher; Becker, Maria R; Bruenn, Kimberly N; Cheung, Timothy; Jendras, Taylor M; Shepley, Aron B; Moeller, John T

2016-12-01

Horizontal gene transfer (HGT) in Borrelia burgdorferi, the Lyme disease agent, is likely mediated by bacteriophage. Studies of the B. burgdorferi phage, ϕBB-1 and its role in HGT have been hindered by the lack of an assay for readily characterizing phage-mediated DNA movement (transduction). Here we describe an in vitro assay in which a clone of B. burgdorferi strain CA-11.2A encoding kanamycin resistance on a ϕBB-1 prophage is co-cultured with different clones encoding gentamicin resistance on a shuttle vector; transduction is monitored by enumerating colonies selected in the presence of both kanamycin and gentamicin. When both clones used in the assay were derived from CA-11.2A, the frequency of transduction was 1.23 × 10 -6 transductants per cell, and could be increased 5-fold by exposing the phage-producing strain to 5% ethanol. Transduction was also demonstrated between the CA-11.2A clone and clones of both high-passage B. burgdorferi strain B31 and low-passage, virulent B. burgdorferi strain 297, although with lower transduction frequencies. The transductant in the 297 background produced phage capable of transducing another B. burgdorferi clone: this is the first experimental demonstration of transduction from a clone of a virulent strain. In addition to prophage DNA, small Escherichia coli-derived shuttle vectors were also transduced between co-cultured B. burgdorferi strains, suggesting both a broad role for the phage in the HGT of heterologous DNA and a potential use of the phage as a molecular tool. These results enhance our understanding of phage-mediated transduction as a mechanism of HGT in the Lyme disease spirochetes. Furthermore, the reagents and techniques developed herein will facilitate future studies of phage-mediated HGT, especially within the tick vector and vertebrate host. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Top-Down CMOS-NEMS Polysilicon Nanowire with Piezoresistive Transduction

PubMed Central

Marigó, Eloi; Sansa, Marc; Pérez-Murano, Francesc; Uranga, Arantxa; Barniol, Núria

2015-01-01

A top-down clamped-clamped beam integrated in a CMOS technology with a cross section of 500 nm × 280 nm has been electrostatic actuated and sensed using two different transduction methods: capacitive and piezoresistive. The resonator made from a single polysilicon layer has a fundamental in-plane resonance at 27 MHz. Piezoresistive transduction avoids the effect of the parasitic capacitance assessing the capability to use it and enhance the CMOS-NEMS resonators towards more efficient oscillator. The displacement derived from the capacitive transduction allows to compute the gauge factor for the polysilicon material available in the CMOS technology. PMID:26184222

Top-Down CMOS-NEMS Polysilicon Nanowire with Piezoresistive Transduction.

PubMed

Marigó, Eloi; Sansa, Marc; Pérez-Murano, Francesc; Uranga, Arantxa; Barniol, Núria

2015-07-14

A top-down clamped-clamped beam integrated in a CMOS technology with a cross section of 500 nm × 280 nm has been electrostatic actuated and sensed using two different transduction methods: capacitive and piezoresistive. The resonator made from a single polysilicon layer has a fundamental in-plane resonance at 27 MHz. Piezoresistive transduction avoids the effect of the parasitic capacitance assessing the capability to use it and enhance the CMOS-NEMS resonators towards more efficient oscillator. The displacement derived from the capacitive transduction allows to compute the gauge factor for the polysilicon material available in the CMOS technology.

Disruption of the Gut Ecosystem by Antibiotics

PubMed Central

2018-01-01

The intestinal microbiota is a complex ecosystem consisting of various microorganisms that expands human genetic repertoire and therefore affects human health and disease. The metabolic processes and signal transduction pathways of the host and intestinal microorganisms are intimately linked, and abnormal progression of each process leads to changes in the intestinal environment. Alterations in microbial communities lead to changes in functional structures based on the metabolites produced in the gut, and these environmental changes result in various bacterial infections and chronic enteric inflammatory diseases. Here, we illustrate how antibiotics are associated with an increased risk of antibiotic-associated diseases by driving intestinal environment changes that favor the proliferation and virulence of pathogens. Understanding the pathogenesis caused by antibiotics would be a crucial key to the treatment of antibiotic-associated diseases by mitigating changes in the intestinal environment and restoring it to its original state. PMID:29214770

C. elegans dauer formation and the molecular basis of plasticity

PubMed Central

Fielenbach, Nicole; Antebi, Adam

2008-01-01

Because life is often unpredictable, dynamic, and complex, all animals have evolved remarkable abilities to cope with changes in their external environment and internal physiology. This regulatory plasticity leads to shifts in behavior and metabolism, as well as to changes in development, growth, and reproduction, which is thought to improve the chances of survival and reproductive success. In favorable environments, the nematode Caenorhabditis elegans develops rapidly to reproductive maturity, but in adverse environments, animals arrest at the dauer diapause, a long-lived stress resistant stage. A molecular and genetic analysis of dauer formation has revealed key insights into how sensory and dietary cues are coupled to conserved endocrine pathways, including insulin/IGF, TGF-β, serotonergic, and steroid hormone signal transduction, which govern the choice between reproduction and survival. These and other pathways reveal a molecular basis for metazoan plasticity in response to extrinsic and intrinsic signals. PMID:18708575

Olfaction Under Metabolic Influences

PubMed Central

2012-01-01

Recently published work and emerging research efforts have suggested that the olfactory system is intimately linked with the endocrine systems that regulate or modify energy balance. Although much attention has been focused on the parallels between taste transduction and neuroendocrine controls of digestion due to the novel discovery of taste receptors and molecular components shared by the tongue and gut, the equivalent body of knowledge that has accumulated for the olfactory system, has largely been overlooked. During regular cycles of food intake or disorders of endocrine function, olfaction is modulated in response to changing levels of various molecules, such as ghrelin, orexins, neuropeptide Y, insulin, leptin, and cholecystokinin. In view of the worldwide health concern regarding the rising incidence of diabetes, obesity, and related metabolic disorders, we present a comprehensive review that addresses the current knowledge of hormonal modulation of olfactory perception and how disruption of hormonal signaling in the olfactory system can affect energy homeostasis. PMID:22832483

Age-related changes in the response of intestinal cells to 1α,25(OH)2-vitamin D3.

PubMed

Gonzalez Pardo, Verónica; Russo de Boland, Ana

2013-01-01

The hormonally active form of vitamin D(3), 1α,25(OH)(2)-vitamin D(3), acts in intestine, its major target tissue, where its actions are of regulatory and developmental importance: regulation of intracellular calcium through modulation of second messengers and activation of mitogenic cascades leading to cell proliferation. Several causes have been postulated to modify the hormone response in intestinal cells with ageing, among them, alterations of vitamin D receptor (VDR) levels and binding sites, reduced expression of G-proteins and hormone signal transduction changes. The current review summarizes the actual knowledge regarding the molecular and biochemical basis of age-impaired 1α,25(OH)(2)-vitamin D(3) receptor-mediated signaling in intestinal cells. A fundamental understanding why the hormone functions are impaired with age will enhance our knowledge of its importance in intestinal cell physiology. Copyright © 2012 Elsevier B.V. All rights reserved.

Recombinant G protein-coupled receptor expression in Saccharomyces cerevisiae for protein characterization.

PubMed

Blocker, Kory M; Britton, Zachary T; Naranjo, Andrea N; McNeely, Patrick M; Young, Carissa L; Robinson, Anne S

2015-01-01

G protein-coupled receptors (GPCRs) are membrane proteins that mediate signaling across the cellular membrane and facilitate cellular responses to external stimuli. Due to the critical role that GPCRs play in signal transduction, therapeutics have been developed to influence GPCR function without an extensive understanding of the receptors themselves. Closing this knowledge gap is of paramount importance to improving therapeutic efficacy and specificity, where efforts to achieve this end have focused chiefly on improving our knowledge of the structure-function relationship. The purpose of this chapter is to review methods for the heterologous expression of GPCRs in Saccharomyces cerevisiae, including whole-cell assays that enable quantitation of expression, localization, and function in vivo. In addition, we describe methods for the micellular solubilization of the human adenosine A2a receptor and for reconstitution of the receptor in liposomes that have enabled its biophysical characterization. © 2015 Elsevier Inc. All rights reserved.

Energy transduction inside vesicles, photocatalysis by titanium dioxide and formation of NADH

NASA Astrophysics Data System (ADS)

Summers, David; Noveron, Juan; Rodoni, David; Basa, Ranor

A number of theories on the origin and early evolution of life have focused on the role of lipid bilayer membrane structures (vesicles). These vesicles are similar to modern cellular membranes , and have been postulated to have been abiotically formed and spontaneously assemble on the prebiotic Earth to provide compartments for early cellular life. They can contain water-soluble species, concentrate species, and have the potential to catalyze reactions. The origin of the use of photochemical energy to drive metabolism (ie. energy transduction) is also one of the central issues in our attempts to understand the origin and evolution of life. When did energy transduction and photosynthesis begin? What was the original system for capturing photochemical energy? How simple can such a system be? It has been postulated that vesicle structures developed the ability to capture and transduce light, providing energy for reactions. It has been shown that pH gradients can be photo-chemically created, but it has been found difficult to couple these to drive chemical reactions. Minerals can introduce a number of properties to a vesicle system. The incorporation of clay particles into vesicles can provide catalytic activity that mediates both vesicle assembly and RNA oligomerization. It is known that colloidal semiconducting mineral particles can act as photocatalysts and drive redox chemistry. We show that encapsulation of these particles has the potential to provide a source of energy transduction inside vesicles, and thereby drive protocellular chemistry and represent a model system for early photosynthesis. TiO2 particles can be incorporated into vesicles and retain their photoactivity through the dehydration/rehydration cycles that have been shown to be able concentrate species inside a vesicle. It is shown that these can be used to produce biochemical species such as enzymatically active NADH in such structures. This system demonstrates a simple energy source inside vesicles/protocells suitable either for simple prebiotic systems and/or for more complex "protobiochemical" systems. It could act as a precursor to metabolic systems and provide a model of how metabolism could have developed prebiotically in a vesicle based "protocell origin of life". It can provide a source of prebiotic compounds inside vesicles, an environment considered to be of great importance for the origin of life. An energy transduction system that is simple enough to have formed at an early stage of the origin of life (even before the formation of enzymatic or ribozymal activity) makes an autotrophic origin of life easier to envision.

Signal transduction in the footsteps of goethe and schiller.

PubMed

Friedrich, Karlheinz; Lindquist, Jonathan A; Entschladen, Frank; Serfling, Edgar; Thiel, Gerald; Kieser, Arnd; Giehl, Klaudia; Ehrhardt, Christina; Feller, Stephan M; Ullrich, Oliver; Schaper, Fred; Janssen, Ottmar; Hass, Ralf

2009-02-04

The historical town of Weimar in Thuringia, the "green heart of Germany" was the sphere of Goethe and Schiller, the two most famous representatives of German literature's classic era. Not yet entirely as influential as those two cultural icons, the Signal Transduction Society (STS) has nevertheless in the last decade established within the walls of Weimar an annual interdisciplinary Meeting on "Signal Transduction - Receptors, Mediators and Genes", which is well recognized as a most attractive opportunity to exchange results and ideas in the field.The 12th STS Meeting was held from October 28 to 31 and provided a state-of-the-art overview of various areas of signal transduction research in which progress is fast and discussion lively. This report is intended to share with the readers of CCS some highlights of the Meeting Workshops devoted to specific aspects of signal transduction.

Enhanced wound healing of tissue-engineered human corneas through altered phosphorylation of the CREB and AKT signal transduction pathways.

PubMed

Couture, Camille; Desjardins, Pascale; Zaniolo, Karine; Germain, Lucie; Guérin, Sylvain L

2018-06-01

The cornea is a transparent organ, highly specialized and unique that is continually subjected to abrasive forces and occasional mechanical or chemical trauma because of its anatomical localization. Upon injury, the extracellular matrix (ECM) rapidly changes to promote wound healing through integrin-dependent activation of specific signal transduction mediators whose contribution is to favor faster closure of the wound by altering the adhesive and migratory properties of the cells surrounding the damaged area. In this study, we exploited the human tissue-engineered cornea (hTECs) as a model to study the signal transduction pathways that participate to corneal wound healing. By exploiting both gene profiling and activated kinases arrays, we could demonstrate the occurrence of important alterations in the level of expression and activation of a few mediators from the PI3K/Akt and CREB pathways in response to the ECM remodeling taking place during wound healing of damaged hTECs. Pharmacological inhibition of CREB with C646 considerably accelerated wound closure compared to controls. This process was considerably accelerated further when both C646 and SC79, an Akt agonist, were added together to wounded hTECs. Therefore, our study demonstrate that proper corneal wound healing requires the activation of Akt together with the inhibition of CREB and that wound healing in vitro can be altered by the use of pharmacological inhibitors (such as C646) or agonists (such as SC79) of these mediators. Corneal wounds account for a large proportion of all visual disabilities in North America. To our knowledge, this is the first time that a tissue-engineered human cornea (hTEC) entirely produced using normal untransformed human cells is used as a biomaterial to study the signal transduction pathways that are critical to corneal wound healing. Through the use of this biomaterial, we demonstrated that human corneal epithelial cells engaged in wound healing reduce phosphorylation of the signal transduction mediator CREB while, in the mean time, they increase that of AKT. By increasing the activation of AKT together with a decrease in CREB activation, we could considerably reduce wound closure time in our punch-damaged hTECs. Considering the increasing interest given to the reconstruction of different types of tissues, we believe these results will have a strong impact on the field of tissue-engineering and biomaterials. Altering the activation status of the Akt and CREB proteins might prove to be a therapeutically interesting avenue and may also find applications in wound healing of other tissues beside the cornea, such as the skin. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The plant cell wall integrity maintenance mechanism--a case study of a cell wall plasma membrane signaling network.

PubMed

Hamann, Thorsten

2015-04-01

Some of the most important functions of plant cell walls are protection against biotic/abiotic stress and structural support during growth and development. A prerequisite for plant cell walls to perform these functions is the ability to perceive different types of stimuli in both qualitative and quantitative manners and initiate appropriate responses. The responses in turn involve adaptive changes in cellular and cell wall metabolism leading to modifications in the structures originally required for perception. While our knowledge about the underlying plant mechanisms is limited, results from Saccharomyces cerevisiae suggest the cell wall integrity maintenance mechanism represents an excellent example to illustrate how the molecular mechanisms responsible for stimulus perception, signal transduction and integration can function. Here I will review the available knowledge about the yeast cell wall integrity maintenance system for illustration purposes, summarize the limited knowledge available about the corresponding plant mechanism and discuss the relevance of the plant cell wall integrity maintenance mechanism in biotic stress responses. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rapid lentiviral transduction preserves the engraftment potential of Fanca(-/-) hematopoietic stem cells.

PubMed

Müller, Lars U W; Milsom, Michael D; Kim, Mi-Ok; Schambach, Axel; Schuesler, Todd; Williams, David A

2008-06-01

Fanconi anemia (FA) is a rare recessive syndrome, characterized by congenital anomalies, bone marrow failure, and predisposition to cancer. Two earlier clinical trials utilizing gamma-retroviral vectors for the transduction of autologous FA hematopoietic stem cells (HSCs) required extensive in vitro manipulation and failed to achieve detectable long-term engraftment of transduced HSCs. As a strategy for minimizing ex vivo manipulation, we investigated the use of a "rapid" lentiviral transduction protocol in a murine Fanca(-/-) model. Importantly, while this and most murine models of FA fail to completely mimic the human hematopoietic phenotype, we observed a high incidence of HSC transplant engraftment failure and low donor chimerism after conventional transduction (CT) of Fanca(-/-) donor cells. In contrast, rapid transduction (RT) of Fanca(-/-) HSCs preserved engraftment to the level achieved in wild-type cells, resulting in long-term multilineage engraftment of gene-modified cells. We also demonstrate the correction of the characteristic hypersensitivity of FA cells against the cross-linking agent mitomycin C (MMC), and provide evidence for the advantage of using pharmacoselection as a means of further increasing gene-modified cells after RT. Collectively, these data support the use of rapid lentiviral transduction for gene therapy in FA.

In vitro modeling of human tibial strains during exercise in micro-gravity

NASA Technical Reports Server (NTRS)

Peterman, M. M.; Hamel, A. J.; Cavanagh, P. R.; Piazza, S. J.; Sharkey, N. A.

2001-01-01

Prolonged exposure to micro-gravity causes substantial bone loss (Leblanc et al., Journal of Bone Mineral Research 11 (1996) S323) and treadmill exercise under gravity replacement loads (GRLs) has been advocated as a countermeasure. To date, the magnitudes of GRLs employed for locomotion in space have been substantially less than the loads imposed in the earthbound 1G environment, which may account for the poor performance of locomotion as an intervention. The success of future treadmill interventions will likely require GRLs of greater magnitude. It is widely held that mechanical tissue strain is an important intermediary signal in the transduction pathway linking the external loading environment to bone maintenance and functional adaptation; yet, to our knowledge, no data exist linking alterations in external skeletal loading to alterations in bone strain. In this preliminary study, we used unique cadaver simulations of micro-gravity locomotion to determine relationships between localized tibial bone strains and external loading as a means to better predict the efficacy of future exercise interventions proposed for bone maintenance on orbit. Bone strain magnitudes in the distal tibia were found to be linearly related to ground reaction force magnitude (R(2)>0.7). Strain distributions indicated that the primary mode of tibial loading was in bending, with little variation in the neutral axis over the stance phase of gait. The greatest strains, as well as the greatest strain sensitivity to altered external loading, occurred within the anterior crest and posterior aspect of the tibia, the sites furthest removed from the neutral axis of bending. We established a technique for estimating local strain magnitudes from external loads, and equations for predicting strain during simulated micro-gravity walking are presented.

[Influence of human gastrointestinal tract bacterial pathogens on host cell apoptosis].

PubMed

Wronowska, Weronika; Godlewska, Renata; Jagusztyn-Krynicka, Elzbieta Katarzyna

2005-01-01

Several pathogenic bacteria are able to trigger apoptosis in the host cell, but the mechanisms by which it occurs differ, and the resulting pathology can take different courses. Induction and/or blockage of programmed cell death upon infection is a result of complex interaction of bacterial proteins with cellular proteins involved in signal transduction and apoptosis. In this review we focus on pro/anti-apoptotic activities exhibited by two enteric pathogens Salmonella enterica, Yersinia spp. and gastric pathogen Helicobacter pylori. We present current knowledge on how interaction between mammalian and bacterial cell relates to the molecular pathways of apoptosis, and what is the role of apoptosis in pathogenesis.

Proteases Revisited: Roles and Therapeutic Implications in Fibrosis

PubMed Central

Kryczka, Jakub

2017-01-01

Proteases target many substrates, triggering changes in distinct biological processes correlated with cell migration, EMT/EndMT and fibrosis. Extracellular protease activity, demonstrated by secreted and membrane-bound protease forms, leads to ECM degradation, activation of other proteases (i.e., proteolysis of nonactive zymogens), decomposition of cell-cell junctions, release of sequestered growth factors (TGF-β and VEGF), activation of signal proteins and receptors, degradation of inflammatory inhibitors or inflammation-related proteins, and changes in cell mechanosensing and motility. Intracellular proteases, mainly caspases and cathepsins, modulate lysosome activity and signal transduction pathways. Herein, we discuss the current knowledge on the multidimensional impact of proteases on the development of fibrosis. PMID:28642633

Primary thermosensory events in cells.

PubMed

Digel, Ilya

2011-01-01

Temperature sensing is essential for the survival of living organisms. Since thermal gradients are almost everywhere, thermoreception could represent one of the oldest sensory transduction processes that evolved in organisms. There are many examples of temperature changes affecting the physiology of living cells. Almost all classes of biological macromolecules in a cell (nucleic acids, lipids, proteins) can serve as a target of the temperature-related stimuli. This review is devoted to some common features of different classes of temperature-sensing molecules as well as molecular and biological processes involved in thermosensation. Biochemical, structural and thermodynamic approaches are discussed in order to overview the existing knowledge on molecular mechanisms of thermosensation.

Regulation of Protein Degradation by O-GlcNAcylation: Crosstalk with Ubiquitination*

PubMed Central

Ruan, Hai-Bin; Nie, Yongzhan; Yang, Xiaoyong

2013-01-01

The post-translational modification of intracellular proteins by O-linked N-acetylglucosamine (O-GlcNAc) regulates essential cellular processes such as signal transduction, transcription, translation, and protein degradation. Misfolded, damaged, and unwanted proteins are tagged with a chain of ubiquitin moieties for degradation by the proteasome, which is critical for cellular homeostasis. In this review, we summarize the current knowledge of the interplay between O-GlcNAcylation and ubiquitination in the control of protein degradation. Understanding the mechanisms of action of O-GlcNAcylation in the ubiquitin-proteosome system shall facilitate the development of therapeutics for human diseases such as cancer, metabolic syndrome, and neurodegenerative diseases. PMID:23824911

Beta-Catenin Stability in Breast Cancer

DTIC Science & Technology

1999-09-01

monoclonal anti-ß-catenin antibody (Clone#14) and the anti-FLAG™ antibody were purchased from Transduction Labs and Kodak, respectively. Affinity purified...anti-HA (BabCo) and anti-ß-catenin antibodies (Transduction labs ). To test the hypothesis that the tumor suppressor adenomatous polyposis coli (APC...ß-catenin was detected first using 1:50 dilution of a mouse monoclonal antibody (Transduction Labs ) followed by Texas Red-conjugated goat anti

Protein diffusion in plant cell plasma membranes: the cell-wall corral.

PubMed

Martinière, Alexandre; Runions, John

2013-01-01

Studying protein diffusion informs us about how proteins interact with their environment. Work on protein diffusion over the last several decades has illustrated the complex nature of biological lipid bilayers. The plasma membrane contains an array of membrane-spanning proteins or proteins with peripheral membrane associations. Maintenance of plasma membrane microstructure can be via physical features that provide intrinsic ordering such as lipid microdomains, or from membrane-associated structures such as the cytoskeleton. Recent evidence indicates, that in the case of plant cells, the cell wall seems to be a major player in maintaining plasma membrane microstructure. This interconnection / interaction between cell-wall and plasma membrane proteins most likely plays an important role in signal transduction, cell growth, and cell physiological responses to the environment.

Decoding Signal Processing at the Single-Cell Level

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiley, H. Steven

The ability of cells to detect and decode information about their extracellular environment is critical to generating an appropriate response. In multicellular organisms, cells must decode dozens of signals from their neighbors and extracellular matrix to maintain tissue homeostasis while still responding to environmental stressors. How cells detect and process information from their surroundings through a surprisingly limited number of signal transduction pathways is one of the most important question in biology. Despite many decades of research, many of the fundamental principles that underlie cell signal processing remain obscure. However, in this issue of Cell Systems, Gillies et al presentmore » compelling evidence that the early response gene circuit can act as a linear signal integrator, thus providing significant insight into how cells handle fluctuating signals and noise in their environment.« less

Characterization of the Adult Head Transcriptome and Identification of Migration and Olfaction Genes in the Oriental Armyworm Mythimna separate.

PubMed

Bian, Hai-Xu; Ma, Hong-Fang; Zheng, Xi-Xi; Peng, Ming-Hui; Li, Yu-Ping; Su, Jun-Fang; Wang, Huan; Li, Qun; Xia, Run-Xi; Liu, Yan-Qun; Jiang, Xing-Fu

2017-05-24

The oriental armyworm Mythimna separate is an economically important insect with a wide distribution and strong migratory activity. However, knowledge about the molecular mechanisms regulating the physiological and behavioural responses of the oriental armyworm is scarce. In the present study, we took a transcriptomic approach to characterize the gene network in the adult head of M. separate. The sequencing and de novo assembly yielded 63,499 transcripts, which were further assembled into 46,459 unigenes with an N50 of 1,153 bp. In the head transcriptome data, unigenes involved in the 'signal transduction mechanism' are the most abundant. In total, 937 signal transduction unigenes were assigned to 22 signalling pathways. The circadian clock, melanin synthesis, and non-receptor protein of olfactory gene families were then identified, and phylogenetic analyses were performed with these M. separate genes, the model insect Bombyx mori and other insects. Furthermore, 1,372 simple sequence repeats of 2-6 bp in unit length were identified. The transcriptome data represent a comprehensive molecular resource for the adult head of M. separate, and these identified genes can be valid targets for further gene function research to address the molecular mechanisms regulating the migratory and olfaction genes of the oriental armyworm.

A Probabilistic Model for Estimating the Depth and Threshold Temperature of C-fiber Nociceptors

PubMed Central

Dezhdar, Tara; Moshourab, Rabih A.; Fründ, Ingo; Lewin, Gary R.; Schmuker, Michael

2015-01-01

The subjective experience of thermal pain follows the detection and encoding of noxious stimuli by primary afferent neurons called nociceptors. However, nociceptor morphology has been hard to access and the mechanisms of signal transduction remain unresolved. In order to understand how heat transducers in nociceptors are activated in vivo, it is important to estimate the temperatures that directly activate the skin-embedded nociceptor membrane. Hence, the nociceptor’s temperature threshold must be estimated, which in turn will depend on the depth at which transduction happens in the skin. Since the temperature at the receptor cannot be accessed experimentally, such an estimation can currently only be achieved through modeling. However, the current state-of-the-art model to estimate temperature at the receptor suffers from the fact that it cannot account for the natural stochastic variability of neuronal responses. We improve this model using a probabilistic approach which accounts for uncertainties and potential noise in system. Using a data set of 24 C-fibers recorded in vitro, we show that, even without detailed knowledge of the bio-thermal properties of the system, the probabilistic model that we propose here is capable of providing estimates of threshold and depth in cases where the classical method fails. PMID:26638830

Signal transduction by VEGF receptors in regulation of angiogenesis and lymphangiogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shibuya, Masabumi; Claesson-Welsh, Lena

2006-03-10

The VEGF/VPF (vascular endothelial growth factor/vascular permeability factor) ligands and receptors are crucial regulators of vasculogenesis, angiogenesis, lymphangiogenesis and vascular permeability in vertebrates. VEGF-A, the prototype VEGF ligand, binds and activates two tyrosine kinase receptors: VEGFR1 (Flt-1) and VEGFR2 (KDR/Flk-1). VEGFR1, which occurs in transmembrane and soluble forms, negatively regulates vasculogenesis and angiogenesis during early embryogenesis, but it also acts as a positive regulator of angiogenesis and inflammatory responses, playing a role in several human diseases such as rheumatoid arthritis and cancer. The soluble VEGFR1 is overexpressed in placenta in preeclampsia patients. VEGFR2 has critical functions in physiological and pathologicalmore » angiogenesis through distinct signal transduction pathways regulating proliferation and migration of endothelial cells. VEGFR3, a receptor for the lymphatic growth factors VEGF-C and VEGF-D, but not for VEGF-A, regulates vascular and lymphatic endothelial cell function during embryogenesis. Loss-of-function variants of VEGFR3 have been identified in lymphedema. Formation of tumor lymphatics may be stimulated by tumor-produced VEGF-C, allowing increased spread of tumor metastases through the lymphatics. Mapping the signaling system of these important receptors may provide the knowledge necessary to suppress specific signaling pathways in major human diseases.« less

Intracellular transduction of TAT-Hsp27 fusion protein enhancing cell survival and regeneration capacity of cardiac stem cells in acute myocardial infarction.

PubMed

Kim, Hye Jung; Kim, Myoung-Hun; Kim, Jong Tae; Lee, Won-Jin; Kim, Eunjung; Lim, Kwang Suk; Kim, Jang Kyoung; Yang, Young Il; Park, Ki Dong; Kim, Yong-Hee

2015-10-10

Myocardial infarction (MI) results in the substantial loss of functional cardiomyocytes, which frequently leads to intractable heart disorders. Cardiac stem cells (CSCs) that retain the capacity to replace all cardiac cells might be a promising strategy for providing a source of new functional cardiomyocytes; however, the poor survival and engraftment of transplanted CSCs in the hostile environment of MI critically mitigate their therapeutic benefits. To capitalize their therapeutic potential, an ex vivo strategy in which CSCs were introduced to the recombinant heat shock protein 27 (Hsp27) through a TAT protein transduction domain for increasing the viability and engraftment in the infarcted myocardium was designed. A recombinant TAT fused Hsp27 (TAT-Hsp27) was able to enter CSCs in a dose-dependent manner. CSCs transduced with TAT-Hsp27 expressed not only endogenous Hsp27 but externally introduced Hsp27, resulting in substantial increase of their anti-oxidative and anti-apoptotic properties via suppressing reactive oxygen species production, the MAPKs signaling pathway, and caspase activation. TAT-Hsp27 enabled CSCs to be protected from apoptotic- and hypoxic-induced cell death during in vitro cardiomyogenic differentiation. In vivo studies demonstrated that CSCs transduced TAT-Hsp27 significantly increased the survival and engraftment in the acutely infarcted myocardium, which is closely related to caspase activity suppression. Finally, CSCs transduced TAT-Hsp27 improved cardiac function and attenuated cardiac remodeling in comparison with non-transduced CSCs. Overall, our approach, which is based on the ex vivo intracellular transduction of TAT-Hsp27 into CSCs before myocardial delivery, might be effective in treating MI. Copyright © 2015 Elsevier B.V. All rights reserved.

Notch2 transduction by feline leukemia virus in a naturally infected cat.

PubMed

Watanabe, Shinya; Ito, Jumpei; Baba, Takuya; Hiratsuka, Takahiro; Kuse, Kyohei; Ochi, Haruyo; Anai, Yukari; Hisasue, Masaharu; Tsujimoto, Hajime; Nishigaki, Kazuo

2014-04-01

Feline leukemia virus (FeLV) induces neoplastic and nonneoplastic diseases in cats. The transduction of cellular genes by FeLV is sometimes observed and associated with neoplastic diseases including lymphoma and sarcoma. Here, we report the first natural case of feline Notch2 transduction by FeLV in an infected cat with multicentric lymphoma and hypercalcemia. We cloned recombinant FeLVs harboring Notch2 in the env gene. Notch2 was able to activate expression of a reporter gene, similar to what was previously reported in cats with experimental FeLV-induced thymic lymphoma. Our findings suggest that the transduction of Notch2 strongly correlates with FeLV-induced lymphoma.

Proteomic plasma profile of psoriatic patients.

PubMed

Gęgotek, Agnieszka; Domingues, Pedro; Wroński, Adam; Wójcik, Piotr; Skrzydlewska, Elżbieta

2018-06-05

Psoriasis is a chronic, immune-mediated inflammatory skin disease with severe consequences for the whole organism. The lack of complete knowledge of the main factors predisposing an individual to the appearance of psoriatic lesions, has recently led to the search for modifications in biochemical pathways participating in the development of this disease. We therefore aimed to investigate changes in the plasma proteomic profile of patients with psoriasis. A proteomics approach was used to analyze the expression of proteins in plasma from psoriatic patients and healthy controls (sex- and age-matched individuals). The analysis was performed using gel electrophoresis, followed by nanoflow LC-MS/MS using a Q-Exactive OrbiTrap mass spectrometer. Proteomic data indicated a significant decrease in the level of proteins involved in lipid metabolism, such as apolipoprotein M, and proteins involved in the management of vitamin D levels in psoriatic patients' plasma. These changes were accompanied by the expression of proteins involved in immune response and signal transduction. This was particularly evident by the level of transcriptional factors, including AT motif binding factor 1, which regulates excessive cellular proliferation and differentiation. It was also suggested that psoriasis development was associated with increased expression of proteins directly involved in signaling molecule secretion [biotinidase and BAI1-associated protein 3]. In addition, the lipid peroxidation product - 4-hydroxynonenal (4-HNE) generates higher level of adducts with proteins in the plasma of psoriatic patients. Moreover, plasma proteins from healthy subjects creating with 4-HNE adducts were mainly characterized as structural, while in the plasma of psoriatic patients, increased levels of 4-HNE-protein adducts with catalytic activity were observed. The results presented herein confirm the current knowledge about the profile of proteins responsible for the immune response and management of vitamin D in the plasma of psoriatic patients. However, several new proteins were also identified, which are involved in signal transduction and lipid metabolism as well as catalytic activity. The expression or structure of these proteins was shown to change through the course of the development of psoriasis. This knowledge may help contribute to the design of more specific pharmacotherapy. Copyright © 2018 Elsevier B.V. All rights reserved.

Ready or Not: Microbial Adaptive Responses in Dynamic Symbiosis Environments.

PubMed

Cao, Mengyi; Goodrich-Blair, Heidi

2017-08-01

In mutually beneficial and pathogenic symbiotic associations, microbes must adapt to the host environment for optimal fitness. Both within an individual host and during transmission between hosts, microbes are exposed to temporal and spatial variation in environmental conditions. The phenomenon of phenotypic variation, in which different subpopulations of cells express distinctive and potentially adaptive characteristics, can contribute to microbial adaptation to a lifestyle that includes rapidly changing environments. The environments experienced by a symbiotic microbe during its life history can be erratic or predictable, and each can impact the evolution of adaptive responses. In particular, the predictability of a rhythmic or cyclical series of environments may promote the evolution of signal transduction cascades that allow preadaptive responses to environments that are likely to be encountered in the future, a phenomenon known as adaptive prediction. In this review, we summarize environmental variations known to occur in some well-studied models of symbiosis and how these may contribute to the evolution of microbial population heterogeneity and anticipatory behavior. We provide details about the symbiosis between Xenorhabdus bacteria and Steinernema nematodes as a model to investigate the concept of environmental adaptation and adaptive prediction in a microbial symbiosis. Copyright © 2017 American Society for Microbiology.

Acid-sensing ion channels and transient-receptor potential ion channels in zebrafish taste buds.

PubMed

Levanti, M; Randazzo, B; Viña, E; Montalbano, G; Garcia-Suarez, O; Germanà, A; Vega, J A; Abbate, F

2016-09-01

Sensory information from the environment is required for life and survival, and it is detected by specialized cells which together make up the sensory system. The fish sensory system includes specialized organs that are able to detect mechanical and chemical stimuli. In particular, taste buds are small organs located on the tongue in terrestrial vertebrates that function in the perception of taste. In fish, taste buds occur on the lips, the flanks, and the caudal (tail) fins of some species and on the barbels of others. In fish taste receptor cells, different classes of ion channels have been detected which, like in mammals, presumably participate in the detection and/or transduction of chemical gustatory signals. However, since some of these ion channels are involved in the detection of additional sensory modalities, it can be hypothesized that taste cells sense stimuli other than those specific for taste. This mini-review summarizes current knowledge on the presence of transient-receptor potential (TRP) and acid-sensing (ASIC) ion channels in the taste buds of teleosts, especially adult zebrafish. Up to now ASIC4, TRPC2, TRPA1, TRPV1 and TRPV4 ion channels have been found in the sensory cells, while ASIC2 was detected in the nerves supplying the taste buds. Copyright © 2016 Elsevier GmbH. All rights reserved.

Mechanical transduction via a single soft polymer

NASA Astrophysics Data System (ADS)

Hou, Ruizheng; Wang, Nan; Bao, Weizhu; Wang, Zhisong

2018-04-01

Molecular machines from biology and nanotechnology often depend on soft structures to perform mechanical functions, but the underlying mechanisms and advantages or disadvantages over rigid structures are not fully understood. We report here a rigorous study of mechanical transduction along a single soft polymer based on exact solutions to the realistic three-dimensional wormlike-chain model and augmented with analytical relations derived from simpler polymer models. The results reveal surprisingly that a soft polymer with vanishingly small persistence length below a single chemical bond still transduces biased displacement and mechanical work up to practically significant amounts. This "soft" approach possesses unique advantages over the conventional wisdom of rigidity-based transduction, and potentially leads to a unified mechanism for effective allosterylike transduction and relay of mechanical actions, information, control, and molecules from one position to another in molecular devices and motors. This study also identifies an entropy limit unique to the soft transduction, and thereby suggests a possibility of detecting higher efficiency for kinesin motor and mutants in future experiments.

Excitation and Adaptation in Bacteria–a Model Signal Transduction System that Controls Taxis and Spatial Pattern Formation

PubMed Central

Othmer, Hans G.; Xin, Xiangrong; Xue, Chuan

2013-01-01

The machinery for transduction of chemotactic stimuli in the bacterium E. coli is one of the most completely characterized signal transduction systems, and because of its relative simplicity, quantitative analysis of this system is possible. Here we discuss models which reproduce many of the important behaviors of the system. The important characteristics of the signal transduction system are excitation and adaptation, and the latter implies that the transduction system can function as a “derivative sensor” with respect to the ligand concentration in that the DC component of a signal is ultimately ignored if it is not too large. This temporal sensing mechanism provides the bacterium with a memory of its passage through spatially- or temporally-varying signal fields, and adaptation is essential for successful chemotaxis. We also discuss some of the spatial patterns observed in populations and indicate how cell-level behavior can be embedded in population-level descriptions. PMID:23624608

[Differentially expressed genes of cell signal transduction associated with benzene poisoning by cDNA microarray].

PubMed

Wang, Hong; Bi, Yongyi; Tao, Ning; Wang, Chunhong

2005-08-01

To detect the differential expression of cell signal transduction genes associated with benzene poisoning, and to explore the pathogenic mechanisms of blood system damage induced by benzene. Peripheral white blood cell gene expression profile of 7 benzene poisoning patients, including one aplastic anemia, was determined by cDNA microarray. Seven chips from normal workers were served as controls. Cluster analysis of gene expression profile was performed. Among the 4265 target genes, 176 genes associated with cell signal transduction were differentially expressed. 35 up-regulated genes including PTPRC, STAT4, IFITM1 etc were found in at least 6 pieces of microarray; 45 down-regulated genes including ARHB, PPP3CB, CDC37 etc were found in at least 5 pieces of microarray. cDNA microarray technology is an effective technique for screening the differentially expressed genes of cell signal transduction. Disorder in cell signal transduction may play certain role in the pathogenic mechanism of benzene poisoning.

Effects of electrode surface structure on the mechanoelectrical transduction of IPMC sensors

NASA Astrophysics Data System (ADS)

Palmre, Viljar; Pugal, David; Kim, Kwang

2014-03-01

This study investigates the effects of electrode surface structure on the mechanoelectrical transduction of IPMC sensors. A physics-based mechanoelectrical transduction model was developed that takes into account the electrode surface profile (shape) by describing the polymer-electrode interface as a Koch fractal structure. Based on the model, the electrode surface effects were experimentally investigated in case of IPMCs with Pd-Pt electrodes. IPMCs with different electrode surface structures were fabricated through electroless plating process by appropriately controlling the synthesis parameters and conditions. The changes in the electrode surface morphology and the corresponding effects on the IPMC mechanoelectrical transduction were examined. Our experimental results indicate that increasing the dispersion of Pd particles near the membrane surface, and thus the polymer-electrode interfacial area, leads to a higher peak mechanoelectrically induced voltage of IPMC. However, the overall effect of the electrode surface structure is relatively low compared to the electromechanical transduction, which is in good agreement with theoretical prediction.

Phosphodiesterase 4D acts downstream of Neuropilin to control Hedgehog signal transduction and the growth of medulloblastoma.

PubMed

Ge, Xuecai; Milenkovic, Ljiljana; Suyama, Kaye; Hartl, Tom; Purzner, Teresa; Winans, Amy; Meyer, Tobias; Scott, Matthew P

2015-09-15

Alterations in Hedgehog (Hh) signaling lead to birth defects and cancers including medulloblastoma, the most common pediatric brain tumor. Although inhibitors targeting the membrane protein Smoothened suppress Hh signaling, acquired drug resistance and tumor relapse call for additional therapeutic targets. Here we show that phosphodiesterase 4D (PDE4D) acts downstream of Neuropilins to control Hh transduction and medulloblastoma growth. PDE4D interacts directly with Neuropilins, positive regulators of Hh pathway. The Neuropilin ligand Semaphorin3 enhances this interaction, promoting PDE4D translocation to the plasma membrane and cAMP degradation. The consequent inhibition of protein kinase A (PKA) enhances Hh transduction. In the developing cerebellum, genetic removal of Neuropilins reduces Hh signaling activity and suppresses proliferation of granule neuron precursors. In mouse medulloblastoma allografts, PDE4D inhibitors suppress Hh transduction and inhibit tumor growth. Our findings reveal a new regulatory mechanism of Hh transduction, and highlight PDE4D as a promising target to treat Hh-related tumors.

De Novo Transcriptome Sequencing and the Hypothetical Cold Response Mode of Saussurea involucrata in Extreme Cold Environments

PubMed Central

Li, Jin; Liu, Hailiang; Xia, Wenwen; Mu, Jianqiang; Feng, Yujie; Liu, Ruina; Yan, Panyao; Wang, Aiying; Lin, Zhongping; Guo, Yong; Zhu, Jianbo; Chen, Xianfeng

2017-01-01

Saussurea involucrata grows in high mountain areas covered by snow throughout the year. The temperature of this habitat can change drastically in one day. To gain a better understanding of the cold response signaling pathways and molecular metabolic reactions involved in cold stress tolerance, genome-wide transcriptional analyses were performed using RNA-Seq technologies. A total of 199,758 transcripts were assembled, producing 138,540 unigenes with 46.8 Gb clean data. Overall, 184,416 (92.32%) transcripts were successfully annotated. The 365 transcription factors identified (292 unigenes) belonged to 49 transcription factor families associated with cold stress responses. A total of 343 transcripts on the signal transduction (132 upregulated and 212 downregulated in at least any one of the conditions) were strongly affected by cold temperature, such as the CBL-interacting serine/threonine-protein kinase (CIPKs), receptor-like protein kinases, and protein kinases. The circadian rhythm pathway was activated by cold adaptation, which was necessary to endure the severe temperature changes within a day. There were 346 differentially expressed genes (DEGs) related to transport, of which 138 were upregulated and 22 were downregulated in at least any one of the conditions. Under cold stress conditions, transcriptional regulation, molecular transport, and signal transduction were involved in the adaptation to low temperature in S. involucrata. These findings contribute to our understanding of the adaptation of plants to harsh environments and the survival traits of S. involucrata. In addition, the present study provides insight into the molecular mechanisms of chilling and freezing tolerance. PMID:28590406

Cardiac Mechano-Gated Ion Channels and Arrhythmias

PubMed Central

Peyronnet, Remi; Nerbonne, Jeanne M.; Kohl, Peter

2015-01-01

Mechanical forces will have been omnipresent since the origin of life, and living organisms have evolved mechanisms to sense, interpret and respond to mechanical stimuli. The cardiovascular system in general, and the heart in particular, are exposed to constantly changing mechanical signals, including stretch, compression, bending, and shear. The heart adjusts its performance to the mechanical environment, modifying electrical, mechanical, metabolic, and structural properties over a range of time scales. Many of the underlying regulatory processes are encoded intra-cardially, and are thus maintained even in heart transplant recipients. Although mechano-sensitivity of heart rhythm has been described in the medical literature for over a century, its molecular mechanisms are incompletely understood. Thanks to modern biophysical and molecular technologies, the roles of mechanical forces in cardiac biology are being explored in more detail, and detailed mechanisms of mechano-transduction have started to emerge. Mechano-gated ion channels are cardiac mechano-receptors. They give rise to mechano-electric feedback, thought to contribute to normal function, disease development, and, potentially, therapeutic interventions. In this review, we focus on acute mechanical effects on cardiac electrophysiology, explore molecular candidates underlying observed responses, and discuss their pharmaceutical regulation. From this, we identify open research questions and highlight emerging technologies that may help in addressing them. Cardiac electrophysiology is acutely affected by the heart’s mechanical environment. Mechano-electric feedback affects excitability, conduction, and electrical load, and remains an underestimated player in arrhythmogenesis. The utility of therapeutic interventions targeting acute mechano-electrical transduction is an open field worthy of further study. PMID:26838316

Experimental validation of a sub-surface model of solar power for distributed marine sensor systems

NASA Astrophysics Data System (ADS)

Hahn, Gregory G.; Cantin, Heather P.; Shafer, Michael W.

2016-04-01

The capabilities of distributed sensor systems such as marine wildlife telemetry tags could be significantly enhanced through the integration of photovoltaic modules. Photovoltaic cells could be used to supplement the primary batteries for wildlife telemetry tags to allow for extended tag deployments, wherein larger amounts of data could be collected and transmitted in near real time. In this article, we present experimental results used to validate and improve key aspects of our original model for sub-surface solar power. We discuss the test methods and results, comparing analytic predictions to experimental results. In a previous work, we introduced a model for sub-surface solar power that used analytic models and empirical data to predict the solar irradiance available for harvest at any depth under the ocean's surface over the course of a year. This model presented underwater photovoltaic transduction as a viable means of supplementing energy for marine wildlife telemetry tags. The additional data provided by improvements in daily energy budgets would enhance the temporal and spatial comprehension of the host's activities and/or environments. Photovoltaic transduction is one method that has not been widely deployed in the sub-surface marine environments despite widespread use on terrestrial and avian species wildlife tag systems. Until now, the use of photovoltaic cells for underwater energy harvesting has generally been disregarded as a viable energy source in this arena. In addition to marine telemetry systems, photovoltaic energy harvesting systems could also serve as a means of energy supply for autonomous underwater vehicles (AUVs), as well as submersible buoys for oceanographic data collection.

FASEB summer research conference on signal transduction in plants. Final report, June 16, 1996--June 21, 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lomax, T.L.; Quatrano, R.S.

1996-12-31

This is the program from the second FASEB conference on Signal Transduction in Plants. Topic areas included the following: environmental signaling; perception and transduction of light signals; signaling in plant microbe interactions; signaling in plant pathogen interactions; cell, cell communication; cytoskeleton, plasma membrane, and cellwall continuum; signaling molecules in plant growth and development I and II. A list of participants is included.

The Role of Claudin-7 in Mouse Mammary Gland and Tumorigenesis

DTIC Science & Technology

2004-07-01

days with minimal inflamma- tory response; however, significant mastitis was observed 12 days after transduction. Adenovirus transduction could also...be used in the virgin animal with little mastitis 3 days after transduction. Transduced mammary epithelial cells maintained normal morphology and...34Clstu- Breeding ILaboratory (Wilmington, Mass.) and maintained in the U.S. Depart- crose permeability is one of the hallmarks of mastitis (9), we used

Targeted Lymphoma Cell Death by Novel Signal Transduction Modifications

DTIC Science & Technology

2010-07-14

CD22 -binding peptides that initiate signal transduction and apoptosis in non-Hodgkin’s lymphoma (NHL), 2) optimize CD22 -mediated signal transduction...and lymphomacidal properties of ligand blocking anti- CD22 monoclonal antibodies (mAbs) and peptides with CD22 -specific phosphatase inhibition and 3...correlate mAb-mediated and anti- CD22 peptide-mediated in vivo physiologic changes, efficacy, and tumor targeting using advanced immuno-positron

Foamy virus–mediated gene transfer to canine repopulating cells

PubMed Central

Kiem, Hans-Peter; Allen, James; Trobridge, Grant; Olson, Erik; Keyser, Kirsten; Peterson, Laura; Russell, David W.

2007-01-01

Foamy virus (FV) vectors are particularly attractive gene-transfer vectors for stem-cell gene therapy because they form a stable transduction intermediate in quiescent cells and can efficiently transduce hematopoietic stem cells. Here, we studied the use of FV vectors to transduce long-term hematopoietic repopulating cells in the dog, a clinically relevant large animal model. Mobilized canine peripheral blood (PB) CD34+ cells were transduced with an enhanced green fluorescent protein (EGFP)–expressing FV vector in an 18-hour transduction protocol. All 3 dogs studied had rapid neutrophil engraftment to greater than 500/μL with a median of 10 days. Transgene expression was detected in all cell lineages (B cells, T cells, granulocytes, red blood cells, and platelets), indicating multilineage engraftment of transduced cells. Up to 19% of blood cells were EGFP+, and this was confirmed at the DNA level by real-time polymerase chain reaction (PCR) and Southern blot analysis. These transduction rates were higher than the best results we obtained previously with lentiviral vectors in a similar transduction protocol. Integration site analysis also demonstrated polyclonal repopulation and the transduction of multipotential hematopoietic repopulating cells. These data suggest that FV vectors should be useful for stem-cell gene therapy, particularly for applications in which short transduction protocols are critical. PMID:16968897

Signal perception, transduction, and response in gravity resistance. Another graviresponse in plants

NASA Astrophysics Data System (ADS)

Hoson, T.; Saito, Y.; Soga, K.; Wakabayashi, K.

Resistance to the gravitational force is a serious problem that plants have had to solve to survive on land. Mechanical resistance to the pull of gravity is thus a principal graviresponse in plants, comparable to gravitropism. Nevertheless, only limited information has been obtained for this gravity response. We have examined the mechanism of gravity-induced mechanical resistance using hypergravity conditions produced by centrifugation. As a result, we have clarified the outline of the sequence of events leading to the development of mechanical resistance. The gravity signal may be perceived by mechanoreceptors (mechanosensitive ion channels) on the plasma membrane and it appears that amyloplast sedimentation in statocytes is not involved. Transformation and transduction of the perceived signal may be mediated by the structural or physiological continuum of microtubule-cell membrane-cell wall. As the final step in the development of mechanical resistance, plants construct a tough body by increasing cell wall rigidity. The increase in cell wall rigidity is brought about by modification of the metabolism of certain wall constituents and modification of the cell wall environment, especially pH. We need to clarify the details of each step by future space and ground-based experiments.

A MAP kinase gene, Clk1, is required for conidiation and pathogenicity in the phytopathogenic fungus Curvularia lunata.

PubMed

Gao, Shi Gang; Zhou, Fei Hong; Liu, Tong; Li, Ying Ying; Chen, Jie

2013-03-01

Mitogen-activated protein kinase (MAPK) cascades are highly conserved signal transduction pathways, which play a wide variety of important roles in extracellular signal transduction. The first MAPK gene of the maize pathogen Curvularia lunata, Clk1, was isolated via a PCR-based approach with a primer pair designed on the basis of conserved regions of known MAPKs. Southern blot analysis showed that the gene existed in the genome as a single copy. The predicted amino acid sequence (352 amino acids) was highly homologous with MAP kinases of other phytopathogenic fungi. Flanking regions of Clk1 were obtained through RACE and genomic walking technology. To understand the role of Clk1 in C. lunata, targeted gene disruption was adopted to construct Clk1 mutants. It was found that mutants lacking functional domain of Clk1 were not able to produce conidia but tended to form a few special chlamydospore-shaped structures. Clk1 mutants grew slower in adverse environments (at 24°C), produced less cell degrading enzymes (CWDEs) than the wild type, and they were almost unable to infect maize leaves via artificial wounds. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Single-Molecule Imaging of Cellular Signaling

NASA Astrophysics Data System (ADS)

De Keijzer, Sandra; Snaar-Jagalska, B. Ewa; Spaink, Herman P.; Schmidt, Thomas

Single-molecule microscopy is an emerging technique to understand the function of a protein in the context of its natural environment. In our laboratory this technique has been used to study the dynamics of signal transduction in vivo. A multitude of signal transduction cascades are initiated by interactions between proteins in the plasma membrane. These cascades start by binding a ligand to its receptor, thereby activating downstream signaling pathways which finally result in complex cellular responses. To fully understand these processes it is important to study the initial steps of the signaling cascades. Standard biological assays mostly call for overexpression of the proteins and high concentrations of ligand. This sets severe limits to the interpretation of, for instance, the time-course of the observations, given the large temporal spread caused by the diffusion-limited binding processes. Methods and limitations of single-molecule microscopy for the study of cell signaling are discussed on the example of the chemotactic signaling of the slime-mold Dictyostelium discoideum. Single-molecule studies, as reviewed in this chapter, appear to be one of the essential methodologies for the full spatiotemporal clarification of cellular signaling, one of the ultimate goals in cell biology.

Walking at non-constant speeds: mechanical work, pendular transduction, and energy congruity.

PubMed

Balbinot, G

2017-05-01

Although almost half of all walking bouts in urban environments consist of less than 12 consecutive steps and several day-to-day gait activities contain transient gait responses, in most studies gait analysis is performed at steady-state. This study aimed to analyze external (W ext ) and internal mechanical work (W int ), pendulum-like mechanics, and elastic energy usage during constant and non-constant speeds. The mechanical work, pendular transduction, and energy congruity (an estimate of storage and release of elastic energy) during walking were computed using two force platforms. We found that during accelerating gait (+NCS) energy recovery is maintained, besides extra W + ext , for decelerating gait (-NCS) poor energy recovery was counterbalanced by W - ext and C% predominance. We report an increase in elastic energy usage with speed (4-11%). Both W - ext and %C suggests that elastic energy usage is higher at faster speeds and related to -NCS (≈20% of elastic energy usage). This study was the first to show evidences of elastic energy usage during constant and non-constant speeds. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Expression of the synaptic exocytosis-regulating molecule complexin 2 in taste buds and its participation in peripheral taste transduction.

PubMed

Kurokawa, Azusa; Narukawa, Masataka; Ohmoto, Makoto; Yoshimoto, Joto; Abe, Keiko; Misaka, Takumi

2015-06-01

Taste information from type III taste cells to gustatory neurons is thought to be transmitted via synapses. However, the molecular mechanisms underlying taste transduction through this pathway have not been fully elucidated. In this study, to identify molecules that participate in synaptic taste transduction, we investigated whether complexins (Cplxs), which play roles in regulating membrane fusion in synaptic vesicle exocytosis, were expressed in taste bud cells. Among four Cplx isoforms, strong expression of Cplx2 mRNA was detected in type III taste cells. To investigate the function of CPLX2 in taste transduction, we observed taste responses in CPLX2-knockout mice. When assessed with electrophysiological and behavioral assays, taste responses to some sour stimuli in CPLX2-knockout mice were significantly lower than those in wild-type mice. These results suggested that CPLX2 participated in synaptic taste transduction from type III taste cells to gustatory neurons. A part of taste information is thought to be transmitted via synapses. However, the molecular mechanisms have not been fully elucidated. To identify molecules that participate in synaptic taste transduction, we investigated complexins (Cplxs) expression in taste bud cells. Strong expression of Cplx2 mRNA was detected in taste bud cells. Furthermore, taste responses to some sour stimuli in CPLX2- knockout mice were significantly lower than those in wild-type mice. These suggested that CPLX2 participated in synaptic taste transduction. © 2015 The Authors. Journal of Neurochemistry published by John Wiley & Sons Ltd on behalf of The International Society for Neurochemistry.

Expression levels of the PiT-2 receptor explain, in part, the gestational age-dependent alterations in transduction efficiency after in utero retroviral-mediated gene transfer

PubMed Central

Ozturk, Ferhat; Park, Paul J.; Tellez, Joseph; Colletti, Evan; Eiden, Maribeth V.; Almeida-Porada, Graça; Porada, Christopher D.

2014-01-01

Background A fundamental obstacle to using retroviral-mediated gene transfer (GT) to treat human diseases is the relatively low transduction levels that have been achieved in clinically relevant human cells. We previously showed that performing GT in utero overcomes this obstacle and results in significant levels of transduction within multiple fetal organs, with different tissues exhibiting optimal transduction at different developmental stages. We undertook the present study aiming to elucidate the mechanism for this age-dependent transduction, testing the two factors that we hypothesized could be responsible: (i) the proliferative status of the tissue at the time of GT and (ii) the expression level of the amphotropic PiT-2 receptor. Methods Immunofluorescence was performed on tissues from sheep of varying developmental stages to assess the proliferative status of the predominant cells within each organ as a function of age. After developing an enzyme-linked immunosorbent assay (ELISA) and a quantitative reverse transcription chain reaction (qRT-PCR) assay, we then quantified PiT-2 expression at the protein and mRNA levels, respectively. Results The results obtained indicate that the proliferative status of organs at the time of fetal GT is not the major determinant governing transduction efficiency. By contrast, our ELISA and qRT-PCR analyses demonstrated that PiT-2 mRNA and protein levels vary with gestational age, correlating with the observed differences in transduction efficiency. Conclusions The findings of the present study explain the age-related differences that we previously observed in transduction efficiency after in utero GT. They also suggest it may be possible to achieve relatively selective GT to specific tissues by performing in utero GT when levels of PiT-2 are maximal in the desired target organ. PMID:22262359

Corporate knowledge repository: Adopting academic LMS into corporate environment

NASA Astrophysics Data System (ADS)

Bakar, Muhamad Shahbani Abu; Jalil, Dzulkafli

2017-10-01

The growth of Knowledge Economy has transformed human capital to be the vital asset in business organization of the 21st century. Arguably, due to its white-collar nature, knowledge-based industry is more favorable than traditional manufacturing business. However, over dependency on human capital can also be a major challenge as any workers will inevitably leave the company or retire. This situation will possibly create knowledge gap that may impact business continuity of the enterprise. Knowledge retention in the corporate environment has been of many research interests. Learning Management System (LMS) refers to the system that provides the delivery, assessment and management tools for an organization to handle its knowledge repository. By using the aspirations of a proven LMS implemented in an academic environment, this paper proposes LMS model that can be used to enable peer-to-peer knowledge capture and sharing in the knowledge-based organization. Cloud Enterprise Resource Planning (ERP), referred to an ERP solution in the internet cloud environment was chosen as the domain knowledge. The complexity of the Cloud ERP business and its knowledge make it very vulnerable to the knowledge retention problem. This paper discusses how the company's essential knowledge can be retained using the LMS system derived from academic environment into the corporate model.

Phase I Trial of Adenovirus-Mediated IL-12 Gene Transduction in Patients with Recurrent Locally Advanced Prostate Cancer Following Therapy

DTIC Science & Technology

2005-10-01

salvage seed implant, cryotherapy ) or who have a rising PSA while on hormone therapy for locally advanced prostate cancer are as follows: a. A...Gene Transduction in Patients with Recurrent Locally Advanced Prostate Cancer Following Therapy PRINCIPAL INVESTIGATOR: Simon J. Hall, MD...CONTRACT NUMBER Phase I Trial of Adenovirus-Mediated IL-12 Gene Transduction in Patients with Recurrent Locally Advanced Prostate Cancer Following

EDITORIAL: Special section on signal transduction Special section on signal transduction

NASA Astrophysics Data System (ADS)

Shvartsman, Stanislav

2012-08-01

This special section of Physical Biology focuses on multiple aspects of signal transduction, broadly defined as the study of the mechanisms by which cells communicate with their environment. Mechanisms of cell communication involve detection of incoming signals, which can be chemical, mechanical or electromagnetic, relaying these signals to intracellular processes, such as cytoskeletal networks or gene expression systems, and, ultimately, converting these signals to responses such as cell differentiation or death. Given the multiscale nature of signal transduction systems, they must be studied at multiple levels, from the identities and structures of molecules comprising signal detection and interpretation networks, to the systems-level properties of these networks. The 11 papers in this special section illustrate some of the most exciting aspects of signal transduction research. The first two papers, by Marie-Anne Félix [1] and by Efrat Oron and Natalia Ivanova [2], focus on cell-cell interactions in developing tissues, using vulval patterning in worm and cell fate specification in mammalian embryos as prime examples of emergent cell behaviors. Next come two papers from the groups of Julio Saez-Rodriguez [3] and Kevin Janes [4]. These papers discuss how the causal relationships between multiple components of signaling systems can be inferred using multivariable statistical analysis of empirical data. An authoritative review by Zarnitsyna and Zhu [5] presents a detailed discussion of the sequence of signaling events involved in T-cell triggering. Once the structure and components of the signaling systems are determined, they can be modeled using approaches that have been successful in other physical sciences. As two examples of such approaches, reviews by Rubinstein [6] and Kholodenko [7], present reaction-diffusion models of cell polarization and thermodynamics-based models of gene regulation. An important class of models takes the form of enzymatic networks, where a single molecule can participate in multiple types of interactions. Mathematical analysis of these models is discussed in the papers by Del Vecchio [8], Seaton and Krishnan [9], and Hatzimanikatis and colleagues [10]. Finally, all signaling systems are information processing devices. While this point is broadly accepted, there have been only a few attempts to apply information theory to experimental signaling systems. A review by Andre Levchenko and colleagues [11] provides a very clear introduction to information theory and its potential applications to signal transduction in cellular systems. References [1] Félix M-A 2012 Phys. Biol. 9 045001 [2] Oron E and Ivanova N 2012 Phys. Biol. 9 045002 [3] MacNamara A et al 2012 Phys. Biol. 9 045003 [4] Jensen K J and Janes K A 2012 Phys. Biol. 9 045004 [5] Zarnitsyna V and Zhu C 2012 Phys. Biol. 9 045005 [6] Rubinstein B et al 2012 Phys. Biol. 9 045006 [7] Frank T D et al 2012 Phys. Biol. 9 045007 [8] Del Vecchio D et al 2012 Phys. Biol. 9 045008 [9] Seaton D D and Krishnan J 2012 Phys. Biol. 9 045009 [10] Radivojevic A et al 2012 Phys. Biol. 9 045010 [11] Rhee A et al 2012 Phys. Biol. 9 045011

Assay for adhesion and agar invasion in S. cerevisiae.

PubMed

Guldal, Cemile G; Broach, James

2006-11-08

Yeasts are found in natural biofilms, where many microorganisms colonize surfaces. In artificial environments, such as surfaces of man-made objects, biofilms can reduce industrial productivity, destroy structures, and threaten human life. 1-3 On the other hand, harnessing the power of biofilms can help clean the environment and generate sustainable energy. 4-8 The ability of S. cerevisiae to colonize surfaces and participate in complex biofilms was mostly ignored until the rediscovery of the differentiation programs triggered by various signaling pathways and environmental cues in this organism. 9, 10 The continuing interest in using S. cerevisiae as a model organism to understand the interaction and convergence of signaling pathways, such as the Ras-PKA, Kss1 MAPK, and Hog1 osmolarity pathways, quickly placed S. cerevisiae in the junction of biofilm biology and signal transduction research. 11-20 To this end, differentiation of yeast cells into long, adhesive, pseudohyphal filaments became a convenient readout for the activation of signal transduction pathways upon various environmental changes. However, filamentation is a complex collection of phenotypes, which makes assaying for it as if it were a simple phenotype misleading. In the past decade, several assays were successfully adopted from bacterial biofilm studies to yeast research, such as MAT formation assays to measure colony spread on soft agar and crystal violet staining to quantitatively measure cell-surface adherence. 12, 21 However, there has been some confusion in assays developed to qualitatively assess the adhesive and invasive phenotypes of yeast in agar. Here, we present a simple and reliable method for assessing the adhesive and invasive quality of yeast strains with easy-to-understand steps to isolate the adhesion assessment from invasion assessment. Our method, adopted from previous studies, 10, 16 involves growing cells in liquid media and plating on differential nutrient conditions for growth of large spots, which we then wash with water to assess adhesion and rub cells completely off the agar surface to assess invasion into the agar. We eliminate the need for streaking cells onto agar, which affects the invasion of cells into the agar. In general, we observed that haploid strains that invade agar are always adhesive, yet not all adhesive strains can invade agar medium. Our approach can be used in conjunction with other assays to carefully dissect the differentiation steps and requirements of yeast signal transduction, differentiation, quorum sensing, and biofilm formation.

Assay for Adhesion and Agar Invasion in S. cerevisiae

PubMed Central

Guldal, Cemile G; Broach, James

2006-01-01

Yeasts are found in natural biofilms, where many microorganisms colonize surfaces. In artificial environments, such as surfaces of man-made objects, biofilms can reduce industrial productivity, destroy structures, and threaten human life. 1-3 On the other hand, harnessing the power of biofilms can help clean the environment and generate sustainable energy. 4-8 The ability of S. cerevisiae to colonize surfaces and participate in complex biofilms was mostly ignored until the rediscovery of the differentiation programs triggered by various signaling pathways and environmental cues in this organism. 9, 10 The continuing interest in using S. cerevisiae as a model organism to understand the interaction and convergence of signaling pathways, such as the Ras-PKA, Kss1 MAPK, and Hog1 osmolarity pathways, quickly placed S. cerevisiae in the junction of biofilm biology and signal transduction research. 11-20 To this end, differentiation of yeast cells into long, adhesive, pseudohyphal filaments became a convenient readout for the activation of signal transduction pathways upon various environmental changes. However, filamentation is a complex collection of phenotypes, which makes assaying for it as if it were a simple phenotype misleading. In the past decade, several assays were successfully adopted from bacterial biofilm studies to yeast research, such as MAT formation assays to measure colony spread on soft agar and crystal violet staining to quantitatively measure cell-surface adherence. 12, 21 However, there has been some confusion in assays developed to qualitatively assess the adhesive and invasive phenotypes of yeast in agar. Here, we present a simple and reliable method for assessing the adhesive and invasive quality of yeast strains with easy-to-understand steps to isolate the adhesion assessment from invasion assessment. Our method, adopted from previous studies, 10, 16 involves growing cells in liquid media and plating on differential nutrient conditions for growth of large spots, which we then wash with water to assess adhesion and rub cells completely off the agar surface to assess invasion into the agar. We eliminate the need for streaking cells onto agar, which affects the invasion of cells into the agar. In general, we observed that haploid strains that invade agar are always adhesive, yet not all adhesive strains can invade agar medium. Our approach can be used in conjunction with other assays to carefully dissect the differentiation steps and requirements of yeast signal transduction, differentiation, quorum sensing, and biofilm formation. PMID:18704175

Global analysis of gene expression profiles in physic nut (Jatropha curcas L.) seedlings exposed to drought stress.

PubMed

Zhang, Chao; Zhang, Lin; Zhang, Sheng; Zhu, Shuang; Wu, Pingzhi; Chen, Yaping; Li, Meiru; Jiang, Huawu; Wu, Guojiang

2015-01-21

Physic nut (Jatropha curcas L.) is a small perennial tree or large shrub, which is well-adapted to semi-arid regions and is considered to have potential as a crop for biofuel production. It is now regarded as an excellent model for studying biofuel plants. However, our knowledge about the molecular responses of this species to drought stress is currently limited. In this study, genome-wide transcriptional profiles of roots and leaves of 8-week old physic nut seedlings were analyzed 1, 4 and 7 days after withholding irrigation. We observed a total of 1533 and 2900 differentially expressed genes (DEGs) in roots and leaves, respectively. Gene Ontology analysis showed that the biological processes enriched in droughted plants relative to unstressed plants were related to biosynthesis, transport, nucleobase-containing compounds, and cellular protein modification. The genes found to be up-regulated in roots were related to abscisic acid (ABA) synthesis and ABA signal transduction, and to the synthesis of raffinose. Genes related to ABA signal transduction, and to trehalose and raffinose synthesis, were up-regulated in leaves. Endoplasmic reticulum (ER) stress response genes were significantly up-regulated in leaves under drought stress, while a number of genes related to wax biosynthesis were also up-regulated in leaves. Genes related to unsaturated fatty acid biosynthesis were down-regulated and polyunsaturated fatty acids were significantly reduced in leaves 7 days after withholding irrigation. As drought stress increased, genes related to ethylene synthesis, ethylene signal transduction and chlorophyll degradation were up-regulated, and the chlorophyll content of leaves was significantly reduced by 7 days after withholding irrigation. This study provides us with new insights to increase our understanding of the response mechanisms deployed by physic nut seedlings under drought stress. The genes and pathways identified in this study also provide much information of potential value for germplasm improvement and breeding for drought resistance.

Environmental attitudes, knowledge, intentions and behaviors among college students.

PubMed

Levine, Debra Siegel; Strube, Michael J

2012-01-01

College students (N = 90) reported their pro-environment behaviors as well as their pro-environment intentions, their explicit and implicit attitudes about the environment, and their knowledge about environmental issues. Intentions and knowledge significantly and independently predicted behavior. Environmental knowledge was not significantly related to attitudes. Implicit and explicit attitudes were significantly but only moderately related. Only explicit attitudes, however, were strongly related to intentions, and intentions completely mediated the influence of explicit attitudes on behavior. Men were found to be more knowledgeable than women about environmental issues; older students had more favorable implicit and explicit environmental attitudes. This research suggests that knowledge about the environment and explicit attitudes influence behavior through different pathways, which may have implications for interventions seeking to increase environmentally friendly behavior.

Designing Computer Learning Environments for Engineering and Computer Science: The Scaffolded Knowledge Integration Framework.

ERIC Educational Resources Information Center

Linn, Marcia C.

1995-01-01

Describes a framework called scaffolded knowledge integration and illustrates how it guided the design of two successful course enhancements in the field of computer science and engineering: the LISP Knowledge Integration Environment and the spatial reasoning environment. (101 references) (Author/MKR)

Recombinant adeno-associated virus serotype 6 (rAAV2/6)-mediated gene transfer to nociceptive neurons through different routes of delivery

PubMed Central

Towne, Chris; Pertin, Marie; Beggah, Ahmed T; Aebischer, Patrick; Decosterd, Isabelle

2009-01-01

Background Gene transfer to nociceptive neurons of the dorsal root ganglia (DRG) is a promising approach to dissect mechanisms of pain in rodents and is a potential therapeutic strategy for the treatment of persistent pain disorders such as neuropathic pain. A number of studies have demonstrated transduction of DRG neurons using herpes simplex virus, adenovirus and more recently, adeno-associated virus (AAV). Recombinant AAV are currently the gene transfer vehicles of choice for the nervous system and have several advantages over other vectors, including stable and safe gene expression. We have explored the capacity of recombinant AAV serotype 6 (rAAV2/6) to deliver genes to DRG neurons and characterized the transduction of nociceptors through five different routes of administration in mice. Results Direct injection of rAAV2/6 expressing green fluorescent protein (eGFP) into the sciatic nerve resulted in transduction of up to 30% eGFP-positive cells of L4 DRG neurons in a dose dependant manner. More than 90% of transduced cells were small and medium sized neurons (< 700 μm2), predominantly colocalized with markers of nociceptive neurons, and had eGFP-positive central terminal fibers in the superficial lamina of the spinal cord dorsal horn. The efficiency and profile of transduction was independent of mouse genetic background. Intrathecal administration of rAAV2/6 gave the highest level of transduction (≈ 60%) and had a similar size profile and colocalization with nociceptive neurons. Intrathecal administration also transduced DRG neurons at cervical and thoracic levels and resulted in comparable levels of transduction in a mouse model for neuropathic pain. Subcutaneous and intramuscular delivery resulted in low levels of transduction in the L4 DRG. Likewise, delivery via tail vein injection resulted in relatively few eGFP-positive cells within the DRG, however, this transduction was observed at all vertebral levels and corresponded to large non-nociceptive cell types. Conclusion We have found that rAAV2/6 is an efficient vector to deliver transgenes to nociceptive neurons in mice. Furthermore, the characterization of the transduction profile may facilitate gene transfer studies to dissect mechanisms behind neuropathic pain. PMID:19737386

Proposed Role for KaiC-Like ATPases as Major Signal Transduction Hubs in Archaea

PubMed Central

2017-01-01

ABSTRACT All organisms must adapt to ever-changing environmental conditions and accordingly have evolved diverse signal transduction systems. In bacteria, the most abundant networks are built around the two-component signal transduction systems that include histidine kinases and receiver domains. In contrast, eukaryotic signal transduction is dominated by serine/threonine/tyrosine protein kinases. Both of these systems are also found in archaea, but they are not as common and diversified as their bacterial and eukaryotic counterparts, suggesting the possibility that archaea have evolved other, still uncharacterized signal transduction networks. Here we propose a role for KaiC family ATPases, known to be key components of the circadian clock in cyanobacteria, in archaeal signal transduction. The KaiC family is notably expanded in most archaeal genomes, and although most of these ATPases remain poorly characterized, members of the KaiC family have been shown to control archaellum assembly and have been found to be a stable component of the gas vesicle system in Halobacteria. Computational analyses described here suggest that KaiC-like ATPases and their homologues with inactivated ATPase domains are involved in many other archaeal signal transduction pathways and comprise major hubs of complex regulatory networks. We predict numerous input and output domains that are linked to KaiC-like proteins, including putative homologues of eukaryotic DEATH domains that could function as adapters in archaeal signaling networks. We further address the relationships of the archaeal family of KaiC homologues to the bona fide KaiC of cyanobacteria and implications for the existence of a KaiC-based circadian clock apparatus in archaea. PMID:29208747

In vivo transduction of primitive mobilized hematopoietic stem cells after intravenous injection of integrating adenovirus vectors

PubMed Central

Richter, Maximilian; Saydaminova, Kamola; Yumul, Roma; Krishnan, Rohini; Liu, Jing; Nagy, Eniko-Eva; Singh, Manvendra; Izsvák, Zsuzsanna; Cattaneo, Roberto; Uckert, Wolfgang; Palmer, Donna; Ng, Philip; Haworth, Kevin G.; Kiem, Hans-Peter; Ehrhardt, Anja; Papayannopoulou, Thalia

2016-01-01

Current protocols for hematopoietic stem/progenitor cell (HSPC) gene therapy, involving the transplantation of ex vivo genetically modified HSPCs are complex and not without risk for the patient. We developed a new approach for in vivo HSPC transduction that does not require myeloablation and transplantation. It involves subcutaneous injections of granulocyte-colony-stimulating factor/AMD3100 to mobilize HSPCs from the bone marrow (BM) into the peripheral blood stream and the IV injection of an integrating, helper-dependent adenovirus (HD-Ad5/35++) vector system. These vectors target CD46, a receptor that is uniformly expressed on HSPCs. We demonstrated in human CD46 transgenic mice and immunodeficient mice with engrafted human CD34+ cells that HSPCs transduced in the periphery home back to the BM where they stably express the transgene. In hCD46 transgenic mice, we showed that our in vivo HSPC transduction approach allows for the stable transduction of primitive HSPCs. Twenty weeks after in vivo transduction, green fluorescent protein (GFP) marking in BM HSPCs (Lin−Sca1+Kit− cells) in most of the mice was in the range of 5% to 10%. The percentage of GFP-expressing primitive HSPCs capable of forming multilineage progenitor colonies (colony-forming units [CFUs]) increased from 4% of all CFUs at week 4 to 16% at week 12, indicating transduction and expansion of long-term surviving HSPCs. Our approach was well tolerated, did not result in significant transduction of nonhematopoietic tissues, and was not associated with genotoxicty. The ability to stably genetically modify HSPCs without the need of myeloablative conditioning is relevant for a broader clinical application of gene therapy. PMID:27554082

Effects of pergolide mesylate on transduction efficiency of PEP-1-catalase protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sohn, Eun Jeong; Kim, Dae Won; Kim, Young Nam

2011-03-18

Research highlights: {yields} We studied effects of pergolide mesylate (PM) on in vitro and in vivo transduction of PEP-1-catalase. {yields} PEP-1-catatase inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation. {yields} PM enhanced the transduction of PEP-1-catalase into HaCaT cells and skin tissue. {yields} PM increased anti-inflammatory activity of PEP-1-catalase. {yields} PM stimulated therapeutic action of anti-oxidant enzyme catalase in oxidative-related diseases. -- Abstract: The low transduction efficiency of various proteins is an obstacle to their therapeutic application. However, protein transduction domains (PTDs) are well-known for a highly effective tool for exogenous protein delivery to cells. We examined the effects of pergolide mesylate (PM) onmore » the transduction of PEP-1-catalase into HaCaT human keratinocytes and mice skin and on the anti-inflammatory activity of PEP-1-catatase against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation using Western blot and histological analysis. PM enhanced the time- and dose-dependent transduction of PEP-1-catalase into HaCaT cells without affecting the cellular toxicity. In a mouse edema model, PEP-1-catalase inhibited the increased expressions of inflammatory mediators and cytokines such as cyclooxygenase-2, inducible nitric oxide synthase, interleukin-6 and -1{beta}, and tumor necrosis factor-{alpha} induced by TPA. On the other hand, PM alone failed to exert any significant anti-inflammatory effects. However, the anti-inflammatory effect of co-treatment with PEP-1-catalase and PM was more potent than that of PEP-1-catalase alone. Our results indicate that PM may enhance the delivery of PTDs fusion therapeutic proteins to target cells and tissues and has potential to increase their therapeutic effects of such drugs against various diseases.« less

A survey of ex vivo/in vitro transduction efficiency of mammalian primary cells and cell lines with Nine natural adeno-associated virus (AAV1-9) and one engineered adeno-associated virus serotype.

PubMed

Ellis, Brian L; Hirsch, Matthew L; Barker, Jenny C; Connelly, Jon P; Steininger, Robert J; Porteus, Matthew H

2013-03-06

The ability to deliver a gene of interest into a specific cell type is an essential aspect of biomedical research. Viruses can be a useful tool for this delivery, particularly in difficult to transfect cell types. Adeno-associated virus (AAV) is a useful gene transfer vector because of its ability to mediate efficient gene transduction in numerous dividing and quiescent cell types, without inducing any known pathogenicity. There are now a number of natural for that designed AAV serotypes that each has a differential ability to infect a variety of cell types. Although transduction studies have been completed, the bulk of the studies have been done in vivo, and there has never been a comprehensive study of transduction ex vivo/in vitro. Each cell type was infected with each serotype at a multiplicity of infection of 100,000 viral genomes/cell and transduction was analyzed by flow cytometry + . We found that AAV1 and AAV6 have the greatest ability to transduce a wide range of cell types, however, for particular cell types, there are specific serotypes that provide optimal transduction. In this work, we describe the transduction efficiency of ten different AAV serotypes in thirty-four different mammalian cell lines and primary cell types. Although these results may not be universal due to numerous factors such as, culture conditions and/ or cell growth rates and cell heterogeneity, these results provide an important and unique resource for investigators who use AAV as an ex vivo gene delivery vector or who work with cells that are difficult to transfect.

Falsification of the ionic channel theory of hair cell transduction.

PubMed

Rossetto, Michelangelo

2013-11-01

The hair cell provides the transduction of mechanical vibrations in the balance and acoustic sense of all vertebrates that swim, walk, or fly. The current theory places hair cell transduction in a mechanically controlled ion channel. Although the theory of a mechanical input modulating the flow of ions through an ion pore has been a useful tool, it is falsified by experimental data in the literature and can be definitively falsified by a proposed experiment.

Falsification of the ionic channel theory of hair cell transduction

PubMed Central

Rossetto, Michelangelo

2013-01-01

The hair cell provides the transduction of mechanical vibrations in the balance and acoustic sense of all vertebrates that swim, walk, or fly. The current theory places hair cell transduction in a mechanically controlled ion channel. Although the theory of a mechanical input modulating the flow of ions through an ion pore has been a useful tool, it is falsified by experimental data in the literature and can be definitively falsified by a proposed experiment. PMID:24563711

Discovery of Intramolecular Signal Transduction Network Based on a New Protein Dynamics Model of Energy Dissipation

PubMed Central

Ma, Cheng-Wei; Xiu, Zhi-Long; Zeng, An-Ping

2012-01-01

A novel approach to reveal intramolecular signal transduction network is proposed in this work. To this end, a new algorithm of network construction is developed, which is based on a new protein dynamics model of energy dissipation. A key feature of this approach is that direction information is specified after inferring protein residue-residue interaction network involved in the process of signal transduction. This enables fundamental analysis of the regulation hierarchy and identification of regulation hubs of the signaling network. A well-studied allosteric enzyme, E. coli aspartokinase III, is used as a model system to demonstrate the new method. Comparison with experimental results shows that the new approach is able to predict all the sites that have been experimentally proved to desensitize allosteric regulation of the enzyme. In addition, the signal transduction network shows a clear preference for specific structural regions, secondary structural types and residue conservation. Occurrence of super-hubs in the network indicates that allosteric regulation tends to gather residues with high connection ability to collectively facilitate the signaling process. Furthermore, a new parameter of propagation coefficient is defined to determine the propagation capability of residues within a signal transduction network. In conclusion, the new approach is useful for fundamental understanding of the process of intramolecular signal transduction and thus has significant impact on rational design of novel allosteric proteins. PMID:22363664

Superior In vivo Transduction of Human Hepatocytes Using Engineered AAV3 Capsid.

PubMed

Vercauteren, Koen; Hoffman, Brad E; Zolotukhin, Irene; Keeler, Geoffrey D; Xiao, Jing W; Basner-Tschakarjan, Etiena; High, Katherine A; Ertl, Hildegund Cj; Rice, Charles M; Srivastava, Arun; de Jong, Ype P; Herzog, Roland W

2016-06-01

Adeno-associated viral (AAV) vectors are currently being tested in multiple clinical trials for liver-directed gene transfer to treat the bleeding disorders hemophilia A and B and metabolic disorders. The optimal viral capsid for transduction of human hepatocytes has been under active investigation, but results across various models are inconsistent. We tested in vivo transduction in "humanized" mice. Methods to quantitate percent AAV transduced human and murine hepatocytes in chimeric livers were optimized using flow cytometry and confocal microscopy with image analysis. Distinct transduction efficiencies were noted following peripheral vein administration of a self-complementary vector expressing a gfp reporter gene. An engineered AAV3 capsid with two amino acid changes, S663V+T492V (AAV3-ST), showed best efficiency for human hepatocytes (~3-times, ~8-times, and ~80-times higher than for AAV9, AAV8, and AAV5, respectively). AAV5, 8, and 9 were more efficient in transducing murine than human hepatocytes. AAV8 yielded the highest transduction rate of murine hepatocytes, which was 19-times higher than that for human hepatocytes. In summary, our data show substantial differences among AAV serotypes in transduction of human and mouse hepatocytes, are the first to report on AAV5 in humanized mice, and support the use of AAV3-based vectors for human liver gene transfer.

Effects of the TAT peptide orientation and relative location on the protein transduction efficiency.

PubMed

Guo, Qingguo; Zhao, Guojie; Hao, Fengjin; Guan, Yifu

2012-05-01

To understand the protein transduction domain (PTD)-mediated protein transduction behavior and to explore its potential in delivering biopharmaceutic drugs, we prepared four TAT-EGFP conjugates: TAT(+)-EGFP, TAT(-)-EGFP, EGFP-TAT(+) and EGFP-TAT(-), where TAT(+) and TAT(-) represent the original and the reversed TAT sequence, respectively. These four TAT-EGFP conjugates were incubated with HeLa and PC12 cells for in vitro study as well as injected intraperitoneally to mice for in vivo study. Flow cytometric results showed that four TAT-EGFP conjugates were able to traverse HeLa and PC12 cells with almost equal transduction efficiency. The in vivo study showed that the TAT-EGFP conjugates could be delivered into different organs of mice with different transduction capabilities. Bioinformatic analyses and CD spectroscopic data revealed that the TAT peptide has no defined secondary structure, and conjugating the TAT peptide to the EGFP cargo protein would not alter the native structure and the function of the EGFP protein. These results conclude that the sequence orientation, the spatial structure, and the relative location of the TAT peptide have much less effect on the TAT-mediated protein transduction. Thus, the TAT-fused conjugates could be constructed in more convenient and flexible formats for a wide range of biopharmaceutical applications. © 2011 John Wiley & Sons A/S.

Characterization of retroviral infectivity and superinfection resistance during retrovirus-mediated transduction of mammalian cells.

PubMed

Liao, J; Wei, Q; Fan, J; Zou, Y; Song, D; Liu, J; Liu, F; Ma, C; Hu, X; Li, L; Yu, Y; Qu, X; Chen, L; Yu, X; Zhang, Z; Zhao, C; Zeng, Z; Zhang, R; Yan, S; Wu, T; Wu, X; Shu, Y; Lei, J; Li, Y; Zhang, W; Wang, J; Reid, R R; Lee, M J; Huang, W; Wolf, J M; He, T-C; Wang, J

2017-06-01

Retroviral vectors including lentiviral vectors are commonly used tools to stably express transgenes or RNA molecules in mammalian cells. Their utilities are roughly divided into two categories, stable overexpression of transgenes and RNA molecules, which requires maximal transduction efficiency, or functional selection with retrovirus (RV)-based libraries, which takes advantage of retroviral superinfection resistance. However, the dynamic features of RV-mediated transduction are not well characterized. Here, we engineered two murine stem cell virus-based retroviral vectors expressing dual fluorescence proteins and antibiotic markers, and analyzed virion production efficiency and virion stability, dynamic infectivity and superinfection resistance in different cell types, and strategies to improve transduction efficiency. We found that the highest virion production occurred between 60 and 72 h after transfection. The stability of the collected virion supernatant decreased by >60% after 3 days in storage. We found that RV infectivity varied drastically in the tested human cancer lines, while low transduction efficiency was partially overcome with increased virus titer, prolonged infection duration and/or repeated infections. Furthermore, we demonstrated that RV receptors PIT1 and PIT2 were lowly expressed in the analyzed cells, and that PIT1 and/or PIT2 overexpression significantly improved transduction efficiency in certain cell lines. Thus, our findings provide resourceful information for the optimal conditions of retroviral-mediated gene delivery.

Improving Collaborative Learning by Supporting Casual Encounters in Distance Learning.

ERIC Educational Resources Information Center

Contreras, Juan; Llamas, Rafael; Vizcaino, Aurora; Vavela, Jesus

Casual encounters in a learning environment are very useful in reinforcing previous knowledge and acquiring new knowledge. Such encounters are very common in traditional learning environments and can be used successfully in social environments in which students can discover and construct knowledge through a process of dialogue, negotiation, or…

The cellular response to vascular endothelial growth factors requires co-ordinated signal transduction, trafficking and proteolysis

PubMed Central

Smith, Gina A.; Fearnley, Gareth W.; Tomlinson, Darren C.; Harrison, Michael A.; Ponnambalam, Sreenivasan

2015-01-01

VEGFs (vascular endothelial growth factors) are a family of conserved disulfide-linked soluble secretory glycoproteins found in higher eukaryotes. VEGFs mediate a wide range of responses in different tissues including metabolic homoeostasis, cell proliferation, migration and tubulogenesis. Such responses are initiated by VEGF binding to soluble and membrane-bound VEGFRs (VEGF receptor tyrosine kinases) and co-receptors. VEGF and receptor splice isoform diversity further enhances complexity of membrane protein assembly and function in signal transduction pathways that control multiple cellular responses. Different signal transduction pathways are simultaneously activated by VEGFR–VEGF complexes with membrane trafficking along the endosome–lysosome network further modulating signal output from multiple enzymatic events associated with such pathways. Balancing VEGFR–VEGF signal transduction with trafficking and proteolysis is essential in controlling the intensity and duration of different intracellular signalling events. Dysfunction in VEGF-regulated signal transduction is important in chronic disease states including cancer, atherosclerosis and blindness. This family of growth factors and receptors is an important model system for understanding human disease pathology and developing new therapeutics for treating such ailments. PMID:26285805

Agrin-LRP4-MuSK signaling as a therapeutic target for myasthenia gravis and other neuromuscular disorders.

PubMed

Ohno, Kinji; Ohkawara, Bisei; Ito, Mikako

2017-10-01

Signal transduction at the neuromuscular junction (NMJ) is compromised in a diverse array of diseases including myasthenia gravis, Lambert-Eaton myasthenic syndrome, Isaacs' syndrome, congenital myasthenic syndromes, Fukuyama-type congenital muscular dystrophy, amyotrophic lateral sclerosis, and sarcopenia. Except for sarcopenia, all are orphan diseases. In addition, the NMJ signal transduction is impaired by tetanus, botulinum, curare, α-bungarotoxin, conotoxins, organophosphate, sarin, VX, and soman to name a few. Areas covered: This review covers the agrin-LRP4-MuSK signaling pathway, which drives clustering of acetylcholine receptors (AChRs) and ensures efficient signal transduction at the NMJ. We also address diseases caused by autoantibodies against the NMJ molecules and by germline mutations in genes encoding the NMJ molecules. Expert opinion: Representative small compounds to treat the defective NMJ signal transduction are cholinesterase inhibitors, which exert their effects by increasing the amount of acetylcholine at the synaptic space. Another possible therapeutic strategy to enhance the NMJ signal transduction is to increase the number of AChRs, but no currently available drug has this functionality.

T-cell receptor transfer into human T cells with ecotropic retroviral vectors.

PubMed

Koste, L; Beissert, T; Hoff, H; Pretsch, L; Türeci, Ö; Sahin, U

2014-05-01

Adoptive T-cell transfer for cancer immunotherapy requires genetic modification of T cells with recombinant T-cell receptors (TCRs). Amphotropic retroviral vectors (RVs) used for TCR transduction for this purpose are considered safe in principle. Despite this, TCR-coding and packaging vectors could theoretically recombine to produce replication competent vectors (RCVs), and transduced T-cell preparations must be proven free of RCV. To eliminate the need for RCV testing, we transduced human T cells with ecotropic RVs so potential RCV would be non-infectious for human cells. We show that transfection of synthetic messenger RNA encoding murine cationic amino-acid transporter 1 (mCAT-1), the receptor for murine retroviruses, enables efficient transient ecotropic transduction of human T cells. mCAT-1-dependent transduction was more efficient than amphotropic transduction performed in parallel, and preferentially targeted naive T cells. Moreover, we demonstrate that ecotropic TCR transduction results in antigen-specific restimulation of primary human T cells. Thus, ecotropic RVs represent a versatile, safe and potent tool to prepare T cells for the adoptive transfer.

Cell proliferation inhibition in reduced gravity

NASA Technical Reports Server (NTRS)

Moos, P. J.; Fattaey, H. K.; Johnson, T. C.; Spooner, B. S. (Principal Investigator)

1994-01-01

Extended durations of spaceflight have been shown to be deleterious on an organismic level; however, mechanisms underlying cellular sensitivity to the gravitational environment remain to be elucidated. The majority of the gravitational studies to date indicates that cell regulatory pathways may be influenced by their gravitational environment. Still, few cell biology experiments have been performed in space flight and even fewer experiments have been repeated on subsequent flights. With flight opportunities on STS-50, 54, and 57, Sf9 cells were flown in the BioServe Fluids Processing Apparatus and cell proliferation was measured with and without exposure to a cell regulatory sialoglycopeptide (CeReS) inhibitor. Results from these flights indicate that the Sf9 cells grew comparable to ground controls, that the CeReS inhibitor bound to its specific receptor, and that its signal transduction cascade was not gravity sensitive.

Exploring the Spatiotemporal Organization of Membrane Proteins in Living Plant Cells.

PubMed

Wang, Li; Xue, Yiqun; Xing, Jingjing; Song, Kai; Lin, Jinxing

2018-04-29

Plasma membrane proteins have important roles in transport and signal transduction. Deciphering the spatiotemporal organization of these proteins provides crucial information for elucidating the links between the behaviors of different molecules. However, monitoring membrane proteins without disrupting their membrane environment remains difficult. Over the past decade, many studies have developed single-molecule techniques, opening avenues for probing the stoichiometry and interactions of membrane proteins in their native environment by providing nanometer-scale spatial information and nanosecond-scale temporal information. In this review, we assess recent progress in the development of labeling and imaging technology for membrane protein analysis. We focus in particular on several single-molecule techniques for quantifying the dynamics and assembly of membrane proteins. Finally, we provide examples of how these new techniques are advancing our understanding of the complex biological functions of membrane proteins.

Regulation of traffic and organelle architecture of the ER-Golgi interface by signal transduction.

PubMed

Tillmann, Kerstin D; Millarte, Valentina; Farhan, Hesso

2013-09-01

The components that control trafficking between organelles of the secretory pathway as well as their architecture were uncovered to a reasonable extent in the past decades. However, only recently did we begin to explore the regulation of the secretory pathway by cellular signaling. In the current review, we focus on trafficking between the endoplasmic reticulum and the Golgi apparatus. We highlight recent advances that have been made toward a better understanding of how the secretory pathway is regulated by signaling and discuss how this knowledge is important to obtain an integrative view of secretion in the context of other homeostatic processes such as growth and proliferation.

Knowledge Acquisition and Job Training for Advanced Technical Skills Using Immersive Virtual Environment

NASA Astrophysics Data System (ADS)

Watanuki, Keiichi; Kojima, Kazuyuki

The environment in which Japanese industry has achieved great respect is changing tremendously due to the globalization of world economies, while Asian countries are undergoing economic and technical development as well as benefiting from the advances in information technology. For example, in the design of custom-made casting products, a designer who lacks knowledge of casting may not be able to produce a good design. In order to obtain a good design and manufacturing result, it is necessary to equip the designer and manufacturer with a support system related to casting design, or a so-called knowledge transfer and creation system. This paper proposes a new virtual reality based knowledge acquisition and job training system for casting design, which is composed of the explicit and tacit knowledge transfer systems using synchronized multimedia and the knowledge internalization system using portable virtual environment. In our proposed system, the education content is displayed in the immersive virtual environment, whereby a trainee may experience work in the virtual site operation. Provided that the trainee has gained explicit and tacit knowledge of casting through the multimedia-based knowledge transfer system, the immersive virtual environment catalyzes the internalization of knowledge and also enables the trainee to gain tacit knowledge before undergoing on-the-job training at a real-time operation site.

Direct mechanical stimulation of tip links in hair cells through DNA tethers

PubMed Central

Basu, Aakash; Lagier, Samuel; Vologodskaia, Maria; Fabella, Brian A; Hudspeth, AJ

2016-01-01

Mechanoelectrical transduction by hair cells commences with hair-bundle deflection, which is postulated to tense filamentous tip links connected to transduction channels. Because direct mechanical stimulation of tip links has not been experimentally possible, this hypothesis has not been tested. We have engineered DNA tethers that link superparamagnetic beads to tip links and exert mechanical forces on the links when exposed to a magnetic-field gradient. By pulling directly on tip links of the bullfrog's sacculus we have evoked transduction currents from hair cells, confirming the hypothesis that tension in the tip links opens transduction channels. This demonstration of direct mechanical access to tip links additionally lays a foundation for experiments probing the mechanics of individual channels. DOI: http://dx.doi.org/10.7554/eLife.16041.001 PMID:27331611

The T-cell-specific adapter protein family: TSAd, ALX, and SH2D4A/SH2D4B.

PubMed

Lapinski, Philip E; Oliver, Jennifer A; Bodie, Jennifer N; Marti, Francesc; King, Philip D

2009-11-01

Adapter proteins play key roles in intracellular signal transduction through complex formation with catalytically active signaling molecules. In T lymphocytes, the role of several different types of adapter proteins in T-cell antigen receptor signal transduction is well established. An exception to this is the family of T-cell-specific adapter (TSAd) proteins comprising of TSAd, adapter protein of unknown function (ALX), SH2D4A, and SH2D4B. Only recently has the function of these adapters in T-cell signal transduction been explored. Here, we discuss advances in our understanding of the role of this family of adapter proteins in T cells. Their function as regulators of signal transduction in other cell types is also discussed.

T cell regulation in microgravity - The current knowledge from in vitro experiments conducted in space, parabolic flights and ground-based facilities

NASA Astrophysics Data System (ADS)

Hauschild, Swantje; Tauber, Svantje; Lauber, Beatrice; Thiel, Cora S.; Layer, Liliana E.; Ullrich, Oliver

2014-11-01

Dating back to the Apollo and Skylab missions, it has been reported that astronauts suffered from bacterial and viral infections during space flight or after returning to Earth. Blood analyses revealed strongly reduced capability of human lymphocytes to become active upon mitogenic stimulation. Since then, a large number of in vitro studies on human immune cells have been conducted in space, in parabolic flights, and in ground-based facilities. It became obvious that microgravity affects cell morphology and important cellular functions. Observed changes include cell proliferation, the cytoskeleton, signal transduction and gene expression. This review gives an overview of the current knowledge of T cell regulation under altered gravity conditions obtained by in vitro studies with special emphasis on the cell culture conditions used. We propose that future in vitro experiments should follow rigorous standardized cell culture conditions, which allows better comparison of the results obtained in different flight- and ground-based experiment platforms.

Development of description framework of pharmacodynamics ontology and its application to possible drug-drug interaction reasoning.

PubMed

Imai, Takeshi; Hayakawa, Masayo; Ohe, Kazuhiko

2013-01-01

Prediction of synergistic or antagonistic effects of drug-drug interaction (DDI) in vivo has been of considerable interest over the years. Formal representation of pharmacological knowledge such as ontology is indispensable for machine reasoning of possible DDIs. However, current pharmacology knowledge bases are not sufficient to provide formal representation of DDI information. With this background, this paper presents: (1) a description framework of pharmacodynamics ontology; and (2) a methodology to utilize pharmacodynamics ontology to detect different types of possible DDI pairs with supporting information such as underlying pharmacodynamics mechanisms. We also evaluated our methodology in the field of drugs related to noradrenaline signal transduction process and 11 different types of possible DDI pairs were detected. The main features of our methodology are the explanation capability of the reason for possible DDIs and the distinguishability of different types of DDIs. These features will not only be useful for providing supporting information to prescribers, but also for large-scale monitoring of drug safety.

Knowledge, Internal, and Environmental Factors on Environmental Care Behaviour among Aboriginal Students in Malaysia

ERIC Educational Resources Information Center

Rahman, Norshariani Abd

2016-01-01

This study determined the contribution of predictor factors (i.e. knowledge about the environment as well as internal and environmental factors) on environmental care behaviour among aboriginal students. The knowledge about the environment that was investigated in this research includes environmental knowledge and environmental action knowledge.…

Andean rural children's views of the environment: A qualitative study

NASA Astrophysics Data System (ADS)

Maurial, Mahia

Andean rural children's drawings and narratives about their crops and the immediate biological environment are rich tools to understand local views of the environment. Children's drawings and narratives were collected and linked to interviews as well as participant observation gathered from parents, leaders and teachers. The research sites are the community of Willca and the school of Mayu. Fieldwork was completed in 1998. In the conceptual framework I distinguish between two dissimilar knowledges, school knowledge and local knowledge. These knowledges produce two dissimilar views of the environment. I further analyze relationships of knowledge and power and argue that school knowledge overpowers local knowledge. Concomitantly, I studied set of ideas associated with two knowledges aforementioned: superacion (surpass) and regeneration (Apffel-Marglin 1995). Although these ideas coexist in peoples' minds they are not linked or effectively connected. In order to link local knowledge and school knowledge together, I propose the integration of environmental studies and art education to enhance a local sense of place (Blandy et. al 1993) in Andean and other schools. This will contribute to grassroots educational policy.

Activation of mTor Signaling by Gene Transduction to Induce Axon Regeneration in the Central Nervous System Following Neural Injury (Addendum)

DTIC Science & Technology

2016-03-01

AD_________________ Award Number: W81XWH-12-1-0051 TITLE: Activation of mTor Signaling by Gene Transduction to Induce Axon Regeneration in the...Activation of mTor Signaling by Gene Transduction to Induce Axon Regeneration in the Central Nervous System Following Neural Injury 5a. CONTRACT NUMBER...incapable of axon regeneration . There are currently two principal concepts that form the basis of our understanding of the inability of the mature

A Genetic Approach to Identifying Signal Transduction Mechanisms Initiated by Receptors for TGF-B-Related Factors.

DTIC Science & Technology

1998-10-01

resistant to TGF-ß-induced growth arrest suggest that both types of receptors are required for signaling (Boyd and Massague, 1989; Laiho et ah, 1990...II in TGF-ß- resistant cell mutants implicates both receptor types in signal transduction. J. Biol. Chem. 265, 18518-18524. Lechleider, R. J., de...I-1 « -J AD GRANT NUMBER DAMD17-94-J-4339 TITLE: A Genetic Approach to Identifying Signal Transduction Mechanisms Initiated by Receptors

Systems Perturbation Analysis of a Large-Scale Signal Transduction Model Reveals Potentially Influential Candidates for Cancer Therapeutics

PubMed Central

Puniya, Bhanwar Lal; Allen, Laura; Hochfelder, Colleen; Majumder, Mahbubul; Helikar, Tomáš

2016-01-01

Dysregulation in signal transduction pathways can lead to a variety of complex disorders, including cancer. Computational approaches such as network analysis are important tools to understand system dynamics as well as to identify critical components that could be further explored as therapeutic targets. Here, we performed perturbation analysis of a large-scale signal transduction model in extracellular environments that stimulate cell death, growth, motility, and quiescence. Each of the model’s components was perturbed under both loss-of-function and gain-of-function mutations. Using 1,300 simulations under both types of perturbations across various extracellular conditions, we identified the most and least influential components based on the magnitude of their influence on the rest of the system. Based on the premise that the most influential components might serve as better drug targets, we characterized them for biological functions, housekeeping genes, essential genes, and druggable proteins. The most influential components under all environmental conditions were enriched with several biological processes. The inositol pathway was found as most influential under inactivating perturbations, whereas the kinase and small lung cancer pathways were identified as the most influential under activating perturbations. The most influential components were enriched with essential genes and druggable proteins. Moreover, known cancer drug targets were also classified in influential components based on the affected components in the network. Additionally, the systemic perturbation analysis of the model revealed a network motif of most influential components which affect each other. Furthermore, our analysis predicted novel combinations of cancer drug targets with various effects on other most influential components. We found that the combinatorial perturbation consisting of PI3K inactivation and overactivation of IP3R1 can lead to increased activity levels of apoptosis-related components and tumor-suppressor genes, suggesting that this combinatorial perturbation may lead to a better target for decreasing cell proliferation and inducing apoptosis. Finally, our approach shows a potential to identify and prioritize therapeutic targets through systemic perturbation analysis of large-scale computational models of signal transduction. Although some components of the presented computational results have been validated against independent gene expression data sets, more laboratory experiments are warranted to more comprehensively validate the presented results. PMID:26904540

Analysis of the gravitaxis signal transduction chain in Euglena gracilis

NASA Astrophysics Data System (ADS)

Nasir, Adeel

Abstract Euglena gracilis is a photosynthetic, eukaryotic flagellate. It can adapt autotrophic and heterotrophic mode of growth and respond to different stimuli, this makes it an organism of choice for different research disciplines. It swims to reach a suitable niche by employing different stimuli such as oxygen, light, gravity and different chemicals. Among these stimuli light and gravity are the most important. Phototaxis (locomotion under light stimulus) and gravitaxis (locomotion under gravity stimulus) synergistically help cells to attain an optimal niche in the environment. However, in the complete absence of light or under scarcity of detectable light, cells can totally depend on gravity to find its swimming path. Therefore gravity has certain advantages over other stimuli.Unlike phototatic signal transduction chain of Euglena gracilis no clear primary gravity receptor has been identified in Euglena cells so far. However, there are some convincing evidence that TRP like channels act as a primary gravity receptor in Euglena gracilis.Use of different inhibitors gave rise to the involvement of protein kinase and calmodulin proteins in signal transduction chain of Euglena gracilis. Recently, specific calmodulin (Calmodulin 2) and protein kinase (PKA) have been identified as potential candidates of gravitactic signal transduction chain. Further characterization and investigation of these candidates was required. Therefore a combination of biochemical and genetic techniques was employed to localize proteins in cells and also to find interacting partners. For localization studies, specific antibodies were raised and characterized. Specificity of antibodies was validated by knockdown mutants, Invitro-translated proteins and heterologously expressed proteins. Cell fractionation studies, involving separation of the cell body and flagella for western blot analysis and confocal immunofluorescence studies were performed for subcellular localization. In order to find interacting partners, yeast two hybrid screen was conducted by using commercially synthesized cDNA library for Euglena gracilis. For both protein kinase and calmodulin some putative interacting partners were found. These plausible candidates are subjected for further validation studies, to verify the protein-protein interaction. In addition, some differential expression studies are also performed for these proteins to evaluate their expression levels under conditions which are known to affect gravitaxis in Euglena gracilis. Taken together, these data are in good agreement with some of already predicted studies for protein localization, but at the same time provides new insights for further studies.

[The role of Smads and related transcription factors in the signal transduction of bone morphogenetic protein inducing bone formation].

PubMed

Xu, Xiao-liang; Dai, Ke-rong; Tang, Ting-ting

2003-09-01

To clarify the mechanisms of the signal transduction of bone morphogenetic proteins (BMPs) inducing bone formation and to provide theoretical basis for basic and applying research of BMPs. We looked up the literature of the role of Smads and related transcription factors in the signal transduction of BMPs inducing bone formation. The signal transduction processes of BMPs included: 1. BMPs combined with type II and type I receptors; 2. the type I receptor phosphorylated Smads; and 3. Smads entered the cell nucleus, interacted with transcription factors and influenced the transcription of related proteins. Smads could be divided into receptor-regulated Smads (R-Smads: Smad1, Smad2, Smad3, Smad5, Smad8 and Smad9), common-mediator Smad (co-Smad: Smad4), and inhibitory Smads (I-Smads: Smad6 and Smad7). Smad1, Smad5, Smad8, and probable Smad9 were involved in the signal transduction of BMPs. Multiple kinases, such as focal adhesion kinase (FAK), Ras-extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase (PI3K), and Akt serine/threonine kinase were related to Smads signal transduction. Smad1 and Smad5 related with transcription factors included core binding factor A1 (CBFA1), smad-interacting protein 1 (SIP1), ornithine decarboxylase antizyme (OAZ), activating protein-1 (AP-1), xenopus ventralizing homeobox protein-2 (Xvent-2), sandostatin (Ski), antiproliferative proteins (Tob), and homeodomain-containing transcriptian factor-8 (Hoxc-8), et al. CBFA1 could interact with Smad1, Smad2, Smad3, and Smad5, so it was involved in TGF-beta and BMP-2 signal transduction, and played an important role in the bone formation. Cleidocranial dysplasia (CCD) was thought to be caused by heterozygous mutations in CBFA1. The CBFA1 knockout mice showed no osteogenesis and had maturational disturbance of chondrocytes. Smads and related transcription factors, especially Smad1, Smad5, Smad8 and CBFA1, play an important role in the signal transduction of BMPs inducing bone formation.

The Influence of Self-Regulated Learning and Prior Knowledge on Knowledge Acquisition in Computer-Based Learning Environments

ERIC Educational Resources Information Center

Bernacki, Matthew

2010-01-01

This study examined how learners construct textbase and situation model knowledge in hypertext computer-based learning environments (CBLEs) and documented the influence of specific self-regulated learning (SRL) tactics, prior knowledge, and characteristics of the learner on posttest knowledge scores from exposure to a hypertext. A sample of 160…

Protein kinase A is part of a mechanism that regulates nuclear reimport of the nuclear tRNA export receptors Los1p and Msn5p.

PubMed

Pierce, Jacqueline B; van der Merwe, George; Mangroo, Dev

2014-02-01

The two main signal transduction mechanisms that allow eukaryotes to sense and respond to changes in glucose availability in the environment are the cyclic AMP (cAMP)/protein kinase A (PKA) and AMP-activated protein kinase (AMPK)/Snf1 kinase-dependent pathways. Previous studies have shown that the nuclear tRNA export process is inhibited in Saccharomyces cerevisiae deprived of glucose. However, the signal transduction pathway involved and the mechanism by which glucose availability regulates nuclear-cytoplasmic tRNA trafficking are not understood. Here, we show that inhibition of nuclear tRNA export is caused by a block in nuclear reimport of the tRNA export receptors during glucose deprivation. Cytoplasmic accumulation of the tRNA export receptors during glucose deprivation is not caused by activation of Snf1p. Evidence obtained suggests that PKA is part of the mechanism that regulates nuclear reimport of the tRNA export receptors in response to glucose availability. This mechanism does not appear to involve phosphorylation of the nuclear tRNA export receptors by PKA. The block in nuclear reimport of the tRNA export receptors appears to be caused by activation of an unidentified mechanism when PKA is turned off during glucose deprivation. Taken together, the data suggest that PKA facilitates return of the tRNA export receptors to the nucleus by inhibiting an unidentified activity that facilitates cytoplasmic accumulation of the tRNA export receptors when glucose in the environment is limiting. A PKA-independent mechanism was also found to regulate nuclear tRNA export in response to glucose availability. This mechanism, however, does not regulate nuclear reimport of the tRNA export receptors.

Protein Kinase A Is Part of a Mechanism That Regulates Nuclear Reimport of the Nuclear tRNA Export Receptors Los1p and Msn5p

PubMed Central

Pierce, Jacqueline B.; van der Merwe, George

2014-01-01

The two main signal transduction mechanisms that allow eukaryotes to sense and respond to changes in glucose availability in the environment are the cyclic AMP (cAMP)/protein kinase A (PKA) and AMP-activated protein kinase (AMPK)/Snf1 kinase-dependent pathways. Previous studies have shown that the nuclear tRNA export process is inhibited in Saccharomyces cerevisiae deprived of glucose. However, the signal transduction pathway involved and the mechanism by which glucose availability regulates nuclear-cytoplasmic tRNA trafficking are not understood. Here, we show that inhibition of nuclear tRNA export is caused by a block in nuclear reimport of the tRNA export receptors during glucose deprivation. Cytoplasmic accumulation of the tRNA export receptors during glucose deprivation is not caused by activation of Snf1p. Evidence obtained suggests that PKA is part of the mechanism that regulates nuclear reimport of the tRNA export receptors in response to glucose availability. This mechanism does not appear to involve phosphorylation of the nuclear tRNA export receptors by PKA. The block in nuclear reimport of the tRNA export receptors appears to be caused by activation of an unidentified mechanism when PKA is turned off during glucose deprivation. Taken together, the data suggest that PKA facilitates return of the tRNA export receptors to the nucleus by inhibiting an unidentified activity that facilitates cytoplasmic accumulation of the tRNA export receptors when glucose in the environment is limiting. A PKA-independent mechanism was also found to regulate nuclear tRNA export in response to glucose availability. This mechanism, however, does not regulate nuclear reimport of the tRNA export receptors. PMID:24297441

Toward high fidelity spectral sensing and RF signal processing in silicon photonic and nano-opto-mechanical platforms

NASA Astrophysics Data System (ADS)

Siddiqui, Aleem; Reinke, Charles; Shin, Heedeuk; Jarecki, Robert L.; Starbuck, Andrew L.; Rakich, Peter

2017-05-01

The performance of electronic systems for radio-frequency (RF) spectrum analysis is critical for agile radar and communications systems, ISR (intelligence, surveillance, and reconnaissance) operations in challenging electromagnetic (EM) environments, and EM-environment situational awareness. While considerable progress has been made in size, weight, and power (SWaP) and performance metrics in conventional RF technology platforms, fundamental limits make continued improvements increasingly difficult. Alternatively, we propose employing cascaded transduction processes in a chip-scale nano-optomechanical system (NOMS) to achieve a spectral sensor with exceptional signal-linearity, high dynamic range, narrow spectral resolution and ultra-fast sweep times. By leveraging the optimal capabilities of photons and phonons, the system we pursue in this work has performance metrics scalable well beyond the fundamental limitations inherent to all electronic systems. In our device architecture, information processing is performed on wide-bandwidth RF-modulated optical signals by photon-mediated phononic transduction of the modulation to the acoustical-domain for narrow-band filtering, and then back to the optical-domain by phonon-mediated phase modulation (the reverse process). Here, we rely on photonics to efficiently distribute signals for parallel processing, and on phononics for effective and flexible RF-frequency manipulation. This technology is used to create RF-filters that are insensitive to the optical wavelength, with wide center frequency bandwidth selectivity (1-100GHz), ultra-narrow filter bandwidth (1-100MHz), and high dynamic range (70dB), which we will present. Additionally, using this filter as a building block, we will discuss current results and progress toward demonstrating a multichannel-filter with a bandwidth of < 10MHz per channel, while minimizing cumulative optical/acoustic/optical transduced insertion-loss to ideally < 10dB. These proposed metric represent significant improvements over RF-platforms.

mom identifies a receptor for the Drosophila JAK/STAT signal transduction pathway and encodes a protein distantly related to the mammalian cytokine receptor family

PubMed Central

Chen, Hua-Wei; Chen, Xiu; Oh, Su-Wan; Marinissen, Maria J.; Gutkind, J. Silvio; Hou, Steven X.

2002-01-01

The JAK/STAT signal transduction pathway controls numerous events in Drosophila melanogaster development. Receptors for the pathway have yet to be identified. Here we have identified a Drosophila gene that shows embryonic mutant phenotypes identical to those in the hopscotch (hop)/JAK kinase and marelle (mrl)/Stat92e mutations. We named this gene master of marelle (mom). Genetic analyses place mom's function between upd (the ligand) and hop. We further show that cultured cells transfected with the mom gene bind UPD and activate the HOP/STAT92E signal transduction pathway. mom encodes a protein distantly related to the mammalian cytokine receptor family. These data show that mom functions as a receptor of the Drosophila JAK/STAT signal transduction pathway. PMID:11825879

Topology of an intracellular transduction chain (phototropism of Phycomyces): 1. Joint review of functional, temporal, and spatial aspects.

PubMed

Wenzler, D; Reinhardt, M; Fukshansky, L

2001-08-21

Two light-induced growth reactions in a unicellular cylindrical sporangiophore of Phycomyces blakesleeanus-vertical growth acceleration under symmetrical irradiation (photomecism) and directional growth under unilateral irradiation (phototropism)-share common input light perception as well as common output growth mechanism but have strongly divergent dynamics and other distinctive features. This divergence culminates in the phototropic paradoxes the main of which states that photomecism shows total adaptation, while phototropism does not adapt. The basis for this contradiction is that the phototropic transduction chain, unlike that of photomecism, faces a spatially non-uniform stimulus and processes a series of spatial patterns (light and absorption profiles, adaptation profile, etc.). The only way to resolve the paradoxes and correlate features of both responses within a single transduction chain is to assume non-local signal transduction, e.g. a cross-talk between different azimuthal locations within the cylindrical cell. On the other hand, to establish the presence of an appropriate cross-talk is equivalent of gaining insight into the topology of the transduction chain. This series of two papers contains a review reconsidering the entire field from this viewpoint (Paper 1) and a mathematical model of pattern transduction which unifies features of phototropism and resolves the paradoxes (Paper 2). At the same time, this is the first "proof of concept" for the "activity/pooling (a/p) networks"-a specific mathematical apparatus designed to analyse systemic properties and control in metabolic pathways. Copyright 2001 Academic Press.

Highly efficient gene transfer using a retroviral vector into murine T cells for preclinical chimeric antigen receptor-expressing T cell therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kusabuka, Hotaka; Fujiwara, Kento; Tokunaga, Yusuke

Adoptive immunotherapy using chimeric antigen receptor-expressing T (CAR-T) cells has attracted attention as an efficacious strategy for cancer treatment. To prove the efficacy and safety of CAR-T cell therapy, the elucidation of immunological mechanisms underlying it in mice is required. Although a retroviral vector (Rv) is mainly used for the introduction of CAR to murine T cells, gene transduction efficiency is generally less than 50%. The low transduction efficiency causes poor precision in the functional analysis of CAR-T cells. We attempted to improve the Rv gene transduction protocol to more efficiently generate functional CAR-T cells by optimizing the period ofmore » pre-cultivation and antibody stimulation. In the improved protocol, gene transduction efficiency to murine T cells was more than 90%. In addition, almost all of the prepared murine T cells expressed CAR after puromycin selection. These CAR-T cells had antigen-specific cytotoxic activity and secreted multiple cytokines by antigen stimulation. We believe that our optimized gene transduction protocol for murine T cells contributes to the advancement of T cell biology and development of immunotherapy using genetically engineered T cells. - Highlights: • We established highly efficient gene transduction protocols for murine T cells. • CD8{sup +} CAR-T cells had antigen-specific cytotoxic activity. • CD4{sup +} CAR-T cells secreted multiple cytokines by antigen stimulation. • This finding can contribute to the development of T-cell biology and immunotherapy.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tenney, Rebeca M.; Bell, Christie L.; Wilson, James M., E-mail: wilsonjm@mail.med.upenn.edu

Adeno-associated virus serotype 8 (AAV8) is a promising vector for liver-directed gene therapy. Although efficient uncoating of viral capsids has been implicated in AAV8's robust liver transduction, much about the biology of AAV8 hepatotropism remains unclear. Our study investigated the structural basis of AAV8 liver transduction efficiency by constructing chimeric vector capsids containing sequences derived from AAV8 and AAV2 – a highly homologous yet poorly hepatotropic serotype. Engineered vectors containing capsid variable regions (VR) VII and IX from AAV8 in an AAV2 backbone mediated near AAV8-like transduction in mouse liver, with higher numbers of chimeric genomes detected in whole livermore » cells and isolated nuclei. Interestingly, chimeric capsids within liver nuclei also uncoated similarly to AAV8 by 6 weeks after administration, in contrast with AAV2, of which a significantly smaller proportion were uncoated. This study links specific AAV capsid regions to the transduction ability of a clinically relevant AAV serotype. - Highlights: • We construct chimeric vectors to identify determinants of AAV8 liver transduction. • An AAV2-based vector with 17 AAV8 residues exhibited high liver transduction in mice. • This vector also surpassed AAV2 in cell entry, nuclear entry and onset of expression. • Most chimeric vector particles were uncoated at 6 weeks, like AAV8 and unlike AAV2. • Chimera retained heparin binding and was antigenically distinct from AAV2 and AAV8.« less

Efficient expansion of human keratinocyte stem/progenitor cells carrying a transgene with lentiviral vector

PubMed Central

2013-01-01

Introduction The development of an appropriate procedure for lentiviral gene transduction into keratinocyte stem cells is crucial for stem cell biology and regenerative medicine for genetic disorders of the skin. However, there is little information available on the efficiency of lentiviral transduction into human keratinocyte stem/progenitor cells and the effects of gene transduction procedures on growth potential of the stem cells by systematic assessment. Methods In this study, we explored the conditions for efficient expansion of human keratinocyte stem/progenitor cells carrying a transgene with a lentiviral vector, by using the culture of keratinocytes on a feeder layer of 3 T3 mouse fibroblasts. The gene transduction and expansion of keratinocytes carrying a transgene were analyzed by Western blotting, quantitative PCR, and flow cytometry. Results Polybrene (hexadiamine bromide) markedly enhanced the efficiency of lentiviral gene transduction, but negatively affected the maintenance of the keratinocyte stem/progenitor cells at a concentration higher than 5 μg/ml. Rho-assiciated kinase (ROCK) inhibitor Y-27632, a small molecule which enhanced keratinocyte proliferation, significantly interfered with the lentiviral transduction into cultured human keratinocytes. However, a suitable combination of polybrene and Y-27632 effectively expanded keratinocytes carrying a transgene. Conclusions This study provides information for effective expansion of cultured human keratinocyte stem/progenitor cells carrying a transgene. This point is particularly significant for the application of genetically modified keratinocyte stem/progenitor stem cells in regenerative medicine. PMID:24406242

Robust imaging and gene delivery to study human lymphoblastoid cell lines.

PubMed

Jolly, Lachlan A; Sun, Ying; Carroll, Renée; Homan, Claire C; Gecz, Jozef

2018-06-20

Lymphoblastoid cell lines (LCLs) have been by far the most prevalent cell type used to study the genetics underlying normal and disease-relevant human phenotypic variation, across personal to epidemiological scales. In contrast, only few studies have explored the use of LCLs in functional genomics and mechanistic studies. Two major reasons are technical, as (1) interrogating the sub-cellular spatial information of LCLs is challenged by their non-adherent nature, and (2) LCLs are refractory to gene transfection. Methodological details relating to techniques that overcome these limitations are scarce, largely inadequate (without additional knowledge and expertise), and optimisation has never been described. Here we compare, optimise, and convey such methods in-depth. We provide a robust method to adhere LCLs to coverslips, which maintained cellular integrity, morphology, and permitted visualisation of sub-cellular structures and protein localisation. Next, we developed the use of lentiviral-based gene delivery to LCLs. Through empirical and combinatorial testing of multiple transduction conditions, we improved transduction efficiency from 3% up to 48%. Furthermore, we established strategies to purify transduced cells, to achieve sustainable cultures containing >85% transduced cells. Collectively, our methodologies provide a vital resource that enables the use of LCLs in functional cell and molecular biology experiments. Potential applications include the characterisation of genetic variants of unknown significance, the interrogation of cellular disease pathways and mechanisms, and high-throughput discovery of genetic modifiers of disease states among others.

The CK1 Family: Contribution to Cellular Stress Response and Its Role in Carcinogenesis

PubMed Central

Knippschild, Uwe; Krüger, Marc; Richter, Julia; Xu, Pengfei; García-Reyes, Balbina; Peifer, Christian; Halekotte, Jakob; Bakulev, Vasiliy; Bischof, Joachim

2014-01-01

Members of the highly conserved and ubiquitously expressed pleiotropic CK1 family play major regulatory roles in many cellular processes including DNA-processing and repair, proliferation, cytoskeleton dynamics, vesicular trafficking, apoptosis, and cell differentiation. As a consequence of cellular stress conditions, interaction of CK1 with the mitotic spindle is manifold increased pointing to regulatory functions at the mitotic checkpoint. Furthermore, CK1 is able to alter the activity of key proteins in signal transduction and signal integration molecules. In line with this notion, CK1 is tightly connected to the regulation and degradation of β-catenin, p53, and MDM2. Considering the importance of CK1 for accurate cell division and regulation of tumor suppressor functions, it is not surprising that mutations and alterations in the expression and/or activity of CK1 isoforms are often detected in various tumor entities including cancer of the kidney, choriocarcinomas, breast carcinomas, oral cancer, adenocarcinomas of the pancreas, and ovarian cancer. Therefore, scientific effort has enormously increased (i) to understand the regulation of CK1 and its involvement in tumorigenesis- and tumor progression-related signal transduction pathways and (ii) to develop CK1-specific inhibitors for the use in personalized therapy concepts. In this review, we summarize the current knowledge regarding CK1 regulation, function, and interaction with cellular proteins playing central roles in cellular stress-responses and carcinogenesis. PMID:24904820

Inquiry into chemotherapy-induced p53 activation in cancer cells as a model for teaching signal transduction.

PubMed

Srougi, Melissa C; Carson, Susan

2013-01-01

Intracellular and extracellular communication is conducted through an intricate and interwoven network of signal transduction pathways. The mechanisms for how cells speak with one another are of significant biological importance to both basic and industrial scientists from a number of different disciplines. We have therefore developed and implemented a new laboratory-intensive course that teaches students the theory and techniques used to study cell signaling pathways. Students learn these methodologies as they conduct a hypothesis-driven research project where they elucidate the mechanism of breast cancer cell death caused by a cancer chemotherapeutic agent. While each lab experiment can be conducted independently, the findings build upon one another to form the beginnings of a signaling pathway. In the lecture component of the course, students investigate different signaling pathways and the methods employed to study them. In addition, students actively participate in journal article discussions where they assess the primary scientific literature. We evaluated the course over two semesters and found that in both semesters learning outcomes were met by both undergraduate and graduate students. The evaluation of the course was based on a number of instructor assessments of student work, including lab reports, experimental results, journal article discussions, and a final cumulative exam. Furthermore, students' self-assessments revealed gains in perceived confidence in both conceptual knowledge and technical skills Copyright © 2013 Wiley-Liss, Inc.

Immortalization of chicken preadipocytes by retroviral transduction of chicken TERT and TR

PubMed Central

Wang, Wei; Zhang, Tianmu; Wu, Chunyan; Wang, Shanshan; Wang, Yuxiang; Wang, Ning

2017-01-01

The chicken is an important agricultural animal and model for developmental biology, immunology and virology. Excess fat accumulation continues to be a serious problem for the chicken industry. However, chicken adipogenesis and obesity have not been well investigated, because no chicken preadipocyte cell lines have been generated thus far. Here, we successfully generated two immortalized chicken preadipocyte cell lines through transduction of either chicken telomerase reverse transcriptase (chTERT) alone or in combination with chicken telomerase RNA (chTR). Both of these cell lines have survived >100 population doublings in vitro, display high telomerase activity and have no sign of replicative senescence. Similar to primary chicken preadipocytes, these two cell lines display a fibroblast-like morphology, retain the capacity to differentiate into adipocytes, and do not display any signs of malignant transformation. Isoenzyme analysis and PCR-based analysis confirmed that these two cell lines are of chicken origin and are free from inter-species contamination. To our knowledge, this is the first report demonstrating the generation of immortal chicken cells by introduction of chTERT and chTR. Our established chicken preadipocyte cell lines show great promise as an in vitro model for the investigation of chicken adipogenesis, lipid metabolism, and obesity and its related diseases, and our results also provide clues for immortalizing other avian cell types. PMID:28486516

Sweet taste transduction in hamster: role of protein kinases.

PubMed

Varkevisser, B; Kinnamon, S C

2000-05-01

Two different second-messenger pathways have been implicated in sweet taste transduction: sugars produce cyclic AMP (cAMP), whereas synthetic sweeteners stimulate production of inositol 1,4, 5-tris-phosphate (IP(3)) and diacylglycerol (DAG). Both sugars and sweeteners depolarize taste cells by blocking the same resting K(+) conductance, but the intermediate steps in the transduction pathways have not been examined. In this study, the loose-patch recording technique was used to examine the role of protein kinases and other downstream regulatory proteins in the two sweet transduction pathways. Bursts of action currents were elicited from approximately 35% of fungiform taste buds in response to sucrose (200 mM) or NC-00274-01 (NC-01, 200 microM), a synthetic sweetener. To determine whether protein kinase C (PKC) plays a role in sweet transduction, taste buds were stimulated with the PKC activator PDBu (10 microM). In all sweet-responsive taste buds tested (n = 11), PDBu elicited burst of action currents. In contrast, PDBu elicited responses in only 4 of 19 sweet-unresponsive taste buds. Inhibition of PKC by bisindolylmaleimide I (0.15 microM) resulted in inhibition of the NC-01 response by approximately 75%, whereas the response to sucrose either increased or remained unchanged. These data suggest that activation of PKC is required for the transduction of synthetic sweeteners. To determine whether protein kinase A (PKA) is required for the transduction of sugars, sweet responses were examined in the presence of the membrane-permeant PKA inhibitor H-89 (10 and 19 microM). Surprisingly, H-89 did not decrease responses to either sucrose or NC-01. Instead, responses to both compounds were increased in the presence of the inhibitor. These data suggest that PKA is not required for the transduction of sugars, but may play a modulatory role in both pathways, such as adaptation of the response. We also examined whether Ca(2+)-calmodulin dependent cAMP phosphodiesterase (CaM-PDE) plays a role in sweet taste transduction, by examining responses to sucrose and synthetic sweeteners in the presence of the CaM-PDE inhibitor W-7 (100 microM). Inhibition resulted in an increase in the response to sucrose, whereas the response to NC-01 remained unchanged. These data suggest that the pathways for sugars and sweeteners are negatively coupled; the Ca(2+) that is released from intracellular stores during stimulation with synthetic sweeteners may inhibit the response to sucrose by activation of CaM-PDE.

Comparative mRNA and MicroRNA Profiling during Acute Myocardial Infarction Induced by Coronary Occlusion and Ablation Radio-Frequency Currents

PubMed Central

Santana, Eduardo T.; Feliciano, Regiane dos Santos; Serra, Andrey J.; Brigidio, Eduardo; Antonio, Ednei L.; Tucci, Paulo J. F.; Nathanson, Lubov; Morris, Mariana; Silva, José A.

2016-01-01

The ligation of the left anterior descending coronary artery is the most commonly used experimental model to induce myocardial infarction (MI) in rodents. A high mortality in the acute phase and the heterogeneity of the size of the MI obtained are drawbacks recognized in this model. In an attempt to solve the problem, our group recently developed a new MI experimental model which is based on application of myocardial ablation radio-frequency currents (AB-RF) that yielded MI with homogeneous sizes and significantly reduce acute mortality. In addition, cardiac structural, and functional changes aroused by AB-RF were similar to those seen in animals with MI induced by coronary artery ligation. Herein, we compared mRNA expression of genes that govern post-MI milieu in occlusion and ablation models. We analyzed 48 mRNAs expressions of nine different signal transduction pathways (cell survival and metabolism signs, matrix extracellular, cell cycle, oxidative stress, apoptosis, calcium signaling, hypertrophy markers, angiogenesis, and inflammation) in rat left ventricle 1 week after MI generated by both coronary occlusion and AB-RF. Furthermore, high-throughput miRNA analysis was also assessed in both MI procedures. Interestingly, mRNA expression levels and miRNA expressions showed strong similarities between both models after MI, with few specificities in each model, activating similar signal transduction pathways. To our knowledge, this is the first comparison of genomic alterations of mRNA and miRNA contents after two different MI procedures and identifies key signaling regulators modulating the pathophysiology of these two models that might culminate in heart failure. Furthermore, these analyses may contribute with the current knowledge concerning transcriptional and post-transcriptional changes of AB-RF protocol, arising as an alternative and effective MI method that reproduces most changes seem in coronary occlusion. PMID:27932994

Does Environmental Knowledge Inhibit Hominin Dispersal?

PubMed

Wren, Colin D; Costopoulos, Andre

2015-07-01

We investigated the relationship between the dispersal potential of a hominin population, its local-scale foraging strategies, and the characteristics of the resource environment using an agent-based modeling approach. In previous work we demonstrated that natural selection can favor a relatively low capacity for assessing and predicting the quality of the resource environment, especially when the distribution of resources is highly clustered. That work also suggested that the more knowledge foraging populations had about their environment, the less likely they were to abandon the landscape they know and disperse into novel territory. The present study gives agents new individual and social strategies for learning about their environment. For both individual and social learning, natural selection favors decreased levels of environmental knowledge, particularly in low-heterogeneity environments. Social acquisition of detailed environmental knowledge results in crowding of agents, which reduces available reproductive space and relative fitness. Agents with less environmental knowledge move away from resource clusters and into areas with more space available for reproduction. These results suggest that, rather than being a requirement for successful dispersal, environmental knowledge strengthens the ties to particular locations and significantly reduces the dispersal potential as a result. The evolved level of environmental knowledge in a population depends on the characteristics of the resource environment and affects the dispersal capacity of the population.

The evolution of traditional knowledge: environment shapes medicinal plant use in Nepal

PubMed Central

Saslis-Lagoudakis, C. Haris; Hawkins, Julie A.; Greenhill, Simon J.; Pendry, Colin A.; Watson, Mark F.; Tuladhar-Douglas, Will; Baral, Sushim R.; Savolainen, Vincent

2014-01-01

Traditional knowledge is influenced by ancestry, inter-cultural diffusion and interaction with the natural environment. It is problematic to assess the contributions of these influences independently because closely related ethnic groups may also be geographically close, exposed to similar environments and able to exchange knowledge readily. Medicinal plant use is one of the most important components of traditional knowledge, since plants provide healthcare for up to 80% of the world's population. Here, we assess the significance of ancestry, geographical proximity of cultures and the environment in determining medicinal plant use for 12 ethnic groups in Nepal. Incorporating phylogenetic information to account for plant evolutionary relatedness, we calculate pairwise distances that describe differences in the ethnic groups' medicinal floras and floristic environments. We also determine linguistic relatedness and geographical separation for all pairs of ethnic groups. We show that medicinal uses are most similar when cultures are found in similar floristic environments. The correlation between medicinal flora and floristic environment was positive and strongly significant, in contrast to the effects of shared ancestry and geographical proximity. These findings demonstrate the importance of adaptation to local environments, even at small spatial scale, in shaping traditional knowledge during human cultural evolution. PMID:24523269

The evolution of traditional knowledge: environment shapes medicinal plant use in Nepal.

PubMed

Saslis-Lagoudakis, C Haris; Hawkins, Julie A; Greenhill, Simon J; Pendry, Colin A; Watson, Mark F; Tuladhar-Douglas, Will; Baral, Sushim R; Savolainen, Vincent

2014-04-07

Traditional knowledge is influenced by ancestry, inter-cultural diffusion and interaction with the natural environment. It is problematic to assess the contributions of these influences independently because closely related ethnic groups may also be geographically close, exposed to similar environments and able to exchange knowledge readily. Medicinal plant use is one of the most important components of traditional knowledge, since plants provide healthcare for up to 80% of the world's population. Here, we assess the significance of ancestry, geographical proximity of cultures and the environment in determining medicinal plant use for 12 ethnic groups in Nepal. Incorporating phylogenetic information to account for plant evolutionary relatedness, we calculate pairwise distances that describe differences in the ethnic groups' medicinal floras and floristic environments. We also determine linguistic relatedness and geographical separation for all pairs of ethnic groups. We show that medicinal uses are most similar when cultures are found in similar floristic environments. The correlation between medicinal flora and floristic environment was positive and strongly significant, in contrast to the effects of shared ancestry and geographical proximity. These findings demonstrate the importance of adaptation to local environments, even at small spatial scale, in shaping traditional knowledge during human cultural evolution.

White collar 2, a partner in blue-light signal transduction, controlling expression of light-regulated genes in Neurospora crassa.

PubMed Central

Linden, H; Macino, G

1997-01-01

A saturating genetic dissection of 'blind' mutants in Neurospora crassa has identified a total of two non-redundant loci (wc-1 and wc-2) each of which is required for blue-light perception/signal transduction. Previously, we demonstrated that WC1 is a putative zinc finger transcription factor able to bind specifically to a light-regulated promoter. Here, we present the cloning and characterization of the wc-2 gene. We demonstrate using mutation analysis and in vitro DNA-binding assays that WC2, the second partner of this light signal transduction system, encodes a functional zinc finger DNA-binding protein with putative PAS dimerization and transcription activation domains. This molecular genetic dissection of the second of two components of this light signal transduction system has enabled us to devise a model whereby WC1 and WC2 are proposed to interact via homologous PAS domains, bind to promoters of light-regulated genes and activate transcription. As such, this study provides the first insight into two co-operating partners in blue-light signal transduction in any organism and describes the molecular tools with which to dissect this enigmatic process. PMID:9009271

Inflammation-induced reversible switch of the neuron-specific enolase promoter from Purkinje neurons to Bergmann glia.

PubMed

Sawada, Yusuke; Konno, Ayumu; Nagaoka, Jun; Hirai, Hirokazu

2016-06-13

Neuron-specific enolase (NSE) is a glycolytic isoenzyme found in mature neurons and cells of neuronal origin. Injecting adeno-associated virus serotype 9 (AAV9) vectors carrying the NSE promoter into the cerebellar cortex is likely to cause the specific transduction of neuronal cells, such as Purkinje cells (PCs) and interneurons, but not Bergmann glia (BG). However, we found BG-predominant transduction without PC transduction along a traumatic needle tract for viral injection. The enhancement of neuroinflammation by the co-application of lipopolysaccharide (LPS) with AAV9 significantly expanded the BG-predominant area concurrently with the potentiated microglial activation. The BG-predominant transduction was gradually replaced by the PC-predominant transduction as the neuroinflammation dissipated. Experiments using glioma cell cultures revealed significant activation of the NSE promoter due to glucose deprivation, suggesting that intracellularly stored glycogen is metabolized through the glycolytic pathway for energy. Activation of the glycolytic enzyme promoter in BG concurrently with inactivation in PC may have pathophysiological significance for the production of lactate in activated BG and the utilization of lactate, which is provided by the BG-PC lactate shuttle, as a primary energy resource in injured PCs.

A versatile targeting system with lentiviral vectors bearing the biotin-adaptor peptide

PubMed Central

Morizono, Kouki; Xie, Yiming; Helguera, Gustavo; Daniels, Tracy R.; Lane, Timothy F.; Penichet, Manuel L.; Chen, Irvin S. Y.

2010-01-01

Background Targeted gene transduction in vivo is the ultimate preferred method for gene delivery. We previously developed targeting lentiviral vectors that specifically recognize cell surface molecules with conjugated antibodies and mediate targeted gene transduction both in vitro and in vivo. Although effective in some experimental settings, the conjugation of virus with antibodies is mediated by the interaction between protein A and the Fc region of antibodies, which is not as stable as covalent conjugation. We have now developed a more stable conjugation strategy utilizing the interaction between avidin and biotin. Methods We inserted the biotin-adaptor-peptide, which was biotinylated by secretory biotin ligase at specific sites, into our targeting envelope proteins, enabling conjugation of the pseudotyped virus with avidin, streptavidin or neutravidin. Results When conjugated with avidin-antibody fusion proteins or the complex of avidin and biotinylated targeting molecules, the vectors could mediate specific transduction to targeted cells recognized by the targeting molecules. When conjugated with streptavidin-coated magnetic beads, transduction by the vectors was targeted to the locations of magnets. Conclusions This targeting vector system can be used for broad applications of targeted gene transduction using biotinylated targeting molecules or targeting molecules fused with avidin. PMID:19455593

Magnetic nanoparticles enhance adenovirus transduction in vitro and in vivo.

PubMed

Sapet, Cédric; Pellegrino, Christophe; Laurent, Nicolas; Sicard, Flavie; Zelphati, Olivier

2012-05-01

Adenoviruses are among the most powerful gene delivery systems. Even if they present low potential for oncogenesis, there is still a need for minimizing widespread delivery to avoid deleterious reactions. In this study, we investigated Magnetofection efficiency to concentrate and guide vectors for an improved targeted delivery. Magnetic nanoparticles formulations were complexed to a replication defective Adenovirus and were used to transduce cells both in vitro and in vivo. A new integrated magnetic procedure for cell sorting and genetic modification (i-MICST) was also investigated. Magnetic nanoparticles enhanced viral transduction efficiency and protein expression in a dose-dependent manner. They accelerated the transduction kinetics and allowed non-permissive cells infection. Magnetofection greatly improved adenovirus-mediated DNA delivery in vivo and provided a magnetic targeting. The i-MICST results established the efficiency of magnetic nanoparticles assisted viral transduction within cell sorting columns. The results showed that the combination of Magnetofection and Adenoviruses represents a promising strategy for gene therapy. Recently, a new integrated method to combine clinically approved magnetic cell isolation devices and genetic modification was developed. In this study, we validated that magnetic cell separation and adenoviral transduction can be accomplished in one reliable integrated and safe system.

Knowledge environments representing molecular entities for the virtual physiological human.

PubMed

Hofmann-Apitius, Martin; Fluck, Juliane; Furlong, Laura; Fornes, Oriol; Kolárik, Corinna; Hanser, Susanne; Boeker, Martin; Schulz, Stefan; Sanz, Ferran; Klinger, Roman; Mevissen, Theo; Gattermayer, Tobias; Oliva, Baldo; Friedrich, Christoph M

2008-09-13

In essence, the virtual physiological human (VPH) is a multiscale representation of human physiology spanning from the molecular level via cellular processes and multicellular organization of tissues to complex organ function. The different scales of the VPH deal with different entities, relationships and processes, and in consequence the models used to describe and simulate biological functions vary significantly. Here, we describe methods and strategies to generate knowledge environments representing molecular entities that can be used for modelling the molecular scale of the VPH. Our strategy to generate knowledge environments representing molecular entities is based on the combination of information extraction from scientific text and the integration of information from biomolecular databases. We introduce @neuLink, a first prototype of an automatically generated, disease-specific knowledge environment combining biomolecular, chemical, genetic and medical information. Finally, we provide a perspective for the future implementation and use of knowledge environments representing molecular entities for the VPH.

Signal transduction in the carnivorous plant Sarracenia purpurea. Regulation of secretory hydrolase expression during development and in response to resources.

PubMed Central

Gallie, D R; Chang, S C

1997-01-01

Carnivory in plants has developed as an evolutionary adaptation to nutrient-poor environments. A significant investment of the resources of a carnivorous plant is committed to producing the traps, attractants, and digestive enzymes needed for the carnivory. The cost:benefit ratio of carnivory can be improved by either maximizing the prey capture rate or by reducing the metabolic commitment toward carnivory. Using the pitcher plant Sarracenia purpurea, we have investigated whether the expression of the hydrolytic enzymes needed for digestion is regulated in response to the presence of prey. Expression of protease, RNase, nuclease, and phosphatase activities could be induced in the fluid of nonactive traps by the addition of nucleic acids, protein, or reduced nitrogen, suggesting that hydrolase expression is induced upon perception of the appropriate chemical signal. Hydrolase expression was also developmentally controlled since expression commenced upon opening of a trap, increased for several days, and in the absence of prey largely ceased within 2 weeks. Nevertheless, the traps remained competent to induce expression in response to the appropriate signals. These data suggest that in young traps hydrolase expression is developmentally regulated, which is later replaced by a signal transduction mechanism, and they demonstrate the ability of a carnivorous species to respond to the availability of resources. PMID:9414556

Signal transduction in the carnivorous plant Sarracenia purpurea. Regulation of secretory hydrolase expression during development and in response to resources.

PubMed

Gallie, D R; Chang, S C

1997-12-01

Carnivory in plants has developed as an evolutionary adaptation to nutrient-poor environments. A significant investment of the resources of a carnivorous plant is committed to producing the traps, attractants, and digestive enzymes needed for the carnivory. The cost:benefit ratio of carnivory can be improved by either maximizing the prey capture rate or by reducing the metabolic commitment toward carnivory. Using the pitcher plant Sarracenia purpurea, we have investigated whether the expression of the hydrolytic enzymes needed for digestion is regulated in response to the presence of prey. Expression of protease, RNase, nuclease, and phosphatase activities could be induced in the fluid of nonactive traps by the addition of nucleic acids, protein, or reduced nitrogen, suggesting that hydrolase expression is induced upon perception of the appropriate chemical signal. Hydrolase expression was also developmentally controlled since expression commenced upon opening of a trap, increased for several days, and in the absence of prey largely ceased within 2 weeks. Nevertheless, the traps remained competent to induce expression in response to the appropriate signals. These data suggest that in young traps hydrolase expression is developmentally regulated, which is later replaced by a signal transduction mechanism, and they demonstrate the ability of a carnivorous species to respond to the availability of resources.

Lipid rafts mediate the interaction between myelin-associated glycoprotein (MAG) on myelin and MAG-receptors on neurons.

PubMed

Vinson, Mary; Rausch, Oliver; Maycox, Peter R; Prinjha, Rab K; Chapman, Debra; Morrow, Rachel; Harper, Alex J; Dingwall, Colin; Walsh, Frank S; Burbidge, Stephen A; Riddell, David R

2003-03-01

The interaction between myelin-associated glycoprotein (MAG), expressed at the periaxonal membrane of myelin, and receptors on neurons initiates a bidirectional signalling system that results in inhibition of neurite outgrowth and maintenance of myelin integrity. We show that this involves a lipid-raft to lipid-raft interaction on opposing cell membranes. MAG is exclusively located in low buoyancy Lubrol WX-insoluble membrane fractions isolated from whole brain, primary oligodendrocytes, or MAG-expressing CHO cells. Localisation within these domains is dependent on cellular cholesterol and occurs following terminal glycosylation in the trans-Golgi network, characteristics of association with lipid rafts. Furthermore, a recombinant form of MAG interacts specifically with lipid-raft fractions from whole brain and cultured cerebellar granule cells, containing functional MAG receptors GT1b and Nogo-66 receptor and molecules required for transduction of signal from MAG into neurons. The localisation of both MAG and MAG receptors within lipid rafts on the surface of opposing cells may create discrete areas of high avidity multivalent interaction, known to be critical for signalling into both cell types. Localisation within lipid rafts may provide a molecular environment that facilitates the interaction between MAG and multiple receptors and also between MAG ligands and molecules involved in signal transduction.

Two-dimensional proteome reference map of Prototheca zopfii revealed reduced metabolism and enhanced signal transduction as adaptation to an infectious life style.

PubMed

Murugaiyan, Jayaseelan; Weise, Christoph; von Bergen, Martin; Roesler, Uwe

2013-09-01

Biochemical, serological, and genetic analyses have identified two genotypes of Prototheca zopfii, a unicellular microalga belonging to the family Chlorellaceae. The P. zopfii genotype 1, abundantly present in cow barns and environment, remains nonpathogenic, while P. zopfii genotype 2 has been isolated from cows with bovine mastitis. The present study was carried out to identify the protein expression level difference between the pathogenic and nonpathogenic strains of P. zopfii. A total of 782 protein spots were observed on the 2D fluorescence difference gel electrophoresis (2D DIGE) gels among which 63 and 44 proteins were identified to be overexpressed in genotypes 1 and 2, respectively. The limited number of protein entries specific for Prototheca in public repositories resulted mainly in the identification of proteins described in other algae, microorganisms, or plants. Gene ontology (GO) analysis indicated reduced carbohydrate metabolism in genotype 1, while genotype 2 displayed enhanced DNA binding, kinase activity, and signal transduction. These effects point to metabolic and signaling adaptations in the pathogenic strain and provide insights into the evolution of otherwise highly similar strains. All MS data have been deposited in the ProteomeXchange with identifier PXD000126. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

VET Students' Integration of Knowledge Engaged with in School-Based and Workplace-Based Learning Environments in the Netherlands

ERIC Educational Resources Information Center

Baartman, L. K. J.; Kilbrink, N.; de Bruijn, E.

2018-01-01

In vocational education, students learn in different school-based and workplace-based learning environments and engage with different types of knowledge in these environments. Students are expected to integrate these experiences and make meaning of them in relation to their own professional knowledge base. This study focuses both on…

Repeat Transduction in the Mouse Lung by Using Adeno-Associated Virus Vectors with Different Serotypes

PubMed Central

Halbert, Christine L.; Rutledge, Elizabeth A.; Allen, James M.; Russell, David W.; Miller, A. Dusty

2000-01-01

Vectors derived from adeno-associated virus type 2 (AAV2) promote gene transfer and expression in the lung; however, we have found that while gene expression can persist for at least 8 months in mice, it was reduced dramatically in rabbits over a period of 2 months. The efficiency and persistence of AAV2-mediated gene expression in the human lung have yet to be determined, but it seems likely that readministration will be necessary over the lifetime of an individual. Unfortunately, we have found that transduction by a second administration of an AAV2 vector is blocked, presumably due to neutralizing antibodies generated in response to the primary vector exposure. Here, we have explored the use of AAV2 vectors pseudotyped with capsid proteins from AAV serotypes 2, 3, and 6 for readministration in the mouse lung. We found that an AAV6 vector transduced airway epithelial and alveolar cells in the lung at rates that were at least as high as those of AAV2 pseudotype vectors, while transduction rates mediated by AAV3 were much lower. AAV6 pseudotype vector transduction was unaffected by prior administration of an AAV2 or AAV3 vector, and transduction by an AAV2 pseudotype vector was unaffected by prior AAV6 vector administration, showing that cross-reactive neutralizing antibodies against AAV2 and AAV6 are not generated in mice. Interestingly, while prior administration of an AAV2 vector completely blocked transduction by a second AAV2 pseudotype vector, prior administration of an AAV6 vector only partially inhibited transduction by a second administration of an AAV6 pseudotype vector. Analysis of sera obtained from mice and humans showed that AAV6 is less immunogenic than AAV2, which helps explain this finding. These results support the development of AAV6 vectors for lung gene therapy both alone and in combination with AAV2 vectors. PMID:10627564

Insulin Therapy Improves Adeno-Associated Virus Transduction of Liver and Skeletal Muscle in Mice and Cultured Cells.

PubMed

Carrig, Sean; Bijjiga, Enoch; Wopat, Mitchell J; Martino, Ashley T

2016-11-01

Adeno-associated virus (AAV) gene transfer is a promising treatment for genetic abnormalities. Optimal AAV vectors are showing success in clinical trials. Gene transfer to skeletal muscle and liver is being explored as a potential therapy for some conditions, that is, α 1 -antitrypsin (AAT) disorder and hemophilia B. Exploring approaches that enhance transduction of liver and skeletal muscle, using these vectors, is beneficial for gene therapy. Regulating hormones as an approach to improve AAV transduction is largely unexplored. In this study we tested whether insulin therapy improves liver and skeletal muscle gene transfer. In vitro studies demonstrated that the temporary coadministration (2, 8, and 24 hr) of insulin significantly improves AAV2-CMV-LacZ transduction of cultured liver cells and differentiated myofibers, but not of lung cells. In addition, there was a dose response related to this improved transduction. Interestingly, when insulin was not coadministered with the virus but given 24 hr afterward, there was no increase in the transgene product. Insulin receptor gene (INSR) expression levels were increased 5- to 13-fold in cultured liver cells and differentiated myofibers when compared with lung cells. Similar INSR gene expression profiles occurred in mouse tissues. Insulin therapy was performed in mice, using a subcutaneously implanted insulin pellet or a high-carbohydrate diet. Insulin treatment began just before intramuscular delivery of AAV1-CMV-schFIX or liver-directed delivery of AAV8-CMV-schFIX and continued for 28 days. Both insulin augmentation therapies improved skeletal muscle- and liver-directed gene transduction in mice as seen by a 3.0- to 4.5-fold increase in human factor IX (hFIX) levels. The improvement was observed even after the insulin therapy ended. Monitoring insulin showed that insulin levels increased during the brief period of rAAV delivery and during the entire insulin augmentation period (28 days). This study demonstrates that AAV transduction of liver or skeletal muscle can be improved by insulin therapy.

Signal Transduction in Histidine Kinases: Insights from New Structures

PubMed Central

Bhate, Manasi P.; Molnar, Kathleen S.; Goulian, Mark; DeGrado, William F.

2015-01-01

Histidine kinases (HKs) are major players in bacterial signaling. There has been an explosion of new HK crystal structures in the last five years. We globally analyze the structures of HKs to yield insights into the mechanisms by which signals are transmitted to and across protein structures in this family. We interpret known enzymological data in the context of new structural data to show how asymmetry across the dimer interface is a key feature of signal transduction in HKs, and discuss how different HK domains undergo asymmetric-to-symmetric transitions during signal transduction and catalysis. A thermodynamic framework for signaling that encompasses these various properties is presented and the consequences of weak thermodynamic coupling are discussed. The synthesis of observations from enzymology, structural biology, protein engineering and thermodynamics paves the way for a deeper molecular understanding of histidine kinase signal transduction. PMID:25982528

Creating a bio-hybrid signal transduction pathway: opening a new channel of communication between cells and machines.

PubMed

Yarkoni, Orr; Donlon, Lynn; Frankel, Daniel

2012-12-01

Manipulation of signal transduction pathways presents a viable mechanism to interface cells with electronics. In this work, we present a two-step signal transduction pathway involving cellular and electronic transduction elements. In order to circumvent many of the conventional difficulties encountered when harnessing chemical signalling for the purpose of electronics communication, gaseous nitric oxide (NO) was selected as the signalling molecule. By genetic engineering of the nitric oxide synthase protein eNOS and insertion of light-oxygen-voltage (LOV) domains, we have created a photoactive version of the protein. The novel chimeric eNOS was found to be capable of producing NO in response to excitation by visible light. By coupling these mutant cells to a surface modified platinum electrode, it was possible to convert an optical signal into a chemical one, followed by subsequent conversion of the chemical signal into an electrical output.

Altering the threshold of an excitable signal transduction network changes cell migratory modes.

PubMed

Miao, Yuchuan; Bhattacharya, Sayak; Edwards, Marc; Cai, Huaqing; Inoue, Takanari; Iglesias, Pablo A; Devreotes, Peter N

2017-04-01

The diverse migratory modes displayed by different cell types are generally believed to be idiosyncratic. Here we show that the migratory behaviour of Dictyostelium was switched from amoeboid to keratocyte-like and oscillatory modes by synthetically decreasing phosphatidylinositol-4,5-bisphosphate levels or increasing Ras/Rap-related activities. The perturbations at these key nodes of an excitable signal transduction network initiated a causal chain of events: the threshold for network activation was lowered, the speed and range of propagating waves of signal transduction activity increased, actin-driven cellular protrusions expanded and, consequently, the cell migratory mode transitions ensued. Conversely, innately keratocyte-like and oscillatory cells were promptly converted to amoeboid by inhibition of Ras effectors with restoration of directed migration. We use computational analysis to explain how thresholds control cell migration and discuss the architecture of the signal transduction network that gives rise to excitability.

Plant response to gravity: towards a biosystems view of root gravitropism

NASA Astrophysics Data System (ADS)

Palme, Klaus; Volkmann, Dieter; Bennett, Malcolm J.; Gausepohl, Heinrich

2005-10-01

Plants are sessile organisms that originated and evolved in Earth's environment. They monitor a wide range of disparate external and internal signals and compute appropriate developmental responses. How do plant cells process these myriad signals into an appropriate response? How do they integrate these signals to reach a finely balanced decision on how to grow, how to determine the direction of growth and how to develop their organs to exploit the environment? As plant responses are generally irreversible growth responses, their signalling systems must compute each developmental decision with extreme care. One stimulus to which plants are continuously exposed is the gravity vector. Gravity affects adaptive growth responses that reorient organs towards light and nutrient resources. The MAP team was established by ESA to study in the model plant Arabidopsis thaliana the role of the hormone auxin in gravity-mediated growth control. Another goal was to dissect gravity perception and gravity signal transduction pathways.

Abiotic Stress Signaling in Wheat – An Inclusive Overview of Hormonal Interactions During Abiotic Stress Responses in Wheat

PubMed Central

Abhinandan, Kumar; Skori, Logan; Stanic, Matija; Hickerson, Neil M. N.; Jamshed, Muhammad; Samuel, Marcus A.

2018-01-01

Rapid global warming directly impacts agricultural productivity and poses a major challenge to the present-day agriculture. Recent climate change models predict severe losses in crop production worldwide due to the changing environment, and in wheat, this can be as large as 42 Mt/°C rise in temperature. Although wheat occupies the largest total harvested area (38.8%) among the cereals including rice and maize, its total productivity remains the lowest. The major production losses in wheat are caused more by abiotic stresses such as drought, salinity, and high temperature than by biotic insults. Thus, understanding the effects of these stresses becomes indispensable for wheat improvement programs which have depended mainly on the genetic variations present in the wheat genome through conventional breeding. Notably, recent biotechnological breakthroughs in the understanding of gene functions and access to whole genome sequences have opened new avenues for crop improvement. Despite the availability of such resources in wheat, progress is still limited to the understanding of the stress signaling mechanisms using model plants such as Arabidopsis, rice and Brachypodium and not directly using wheat as the model organism. This review presents an inclusive overview of the phenotypic and physiological changes in wheat due to various abiotic stresses followed by the current state of knowledge on the identified mechanisms of perception and signal transduction in wheat. Specifically, this review provides an in-depth analysis of different hormonal interactions and signaling observed during abiotic stress signaling in wheat. PMID:29942321

Plant-pathogen interactions: what microarray tells about it?

PubMed

Lodha, T D; Basak, J

2012-01-01

Plant defense responses are mediated by elementary regulatory proteins that affect expression of thousands of genes. Over the last decade, microarray technology has played a key role in deciphering the underlying networks of gene regulation in plants that lead to a wide variety of defence responses. Microarray is an important tool to quantify and profile the expression of thousands of genes simultaneously, with two main aims: (1) gene discovery and (2) global expression profiling. Several microarray technologies are currently in use; most include a glass slide platform with spotted cDNA or oligonucleotides. Till date, microarray technology has been used in the identification of regulatory genes, end-point defence genes, to understand the signal transduction processes underlying disease resistance and its intimate links to other physiological pathways. Microarray technology can be used for in-depth, simultaneous profiling of host/pathogen genes as the disease progresses from infection to resistance/susceptibility at different developmental stages of the host, which can be done in different environments, for clearer understanding of the processes involved. A thorough knowledge of plant disease resistance using successful combination of microarray and other high throughput techniques, as well as biochemical, genetic, and cell biological experiments is needed for practical application to secure and stabilize yield of many crop plants. This review starts with a brief introduction to microarray technology, followed by the basics of plant-pathogen interaction, the use of DNA microarrays over the last decade to unravel the mysteries of plant-pathogen interaction, and ends with the future prospects of this technology.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giuliani, Sarah E; Frank, Ashley M; Corgliano, Danielle M

Abstract Background: Transporter proteins are one of an organism s primary interfaces with the environment. The expressed set of transporters mediates cellular metabolic capabilities and influences signal transduction pathways and regulatory networks. The functional annotation of most transporters is currently limited to general classification into families. The development of capabilities to map ligands with specific transporters would improve our knowledge of the function of these proteins, improve the annotation of related genomes, and facilitate predictions for their role in cellular responses to environmental changes. Results: To improve the utility of the functional annotation for ABC transporters, we expressed and purifiedmore » the set of solute binding proteins from Rhodopseudomonas palustris and characterized their ligand-binding specificity. Our approach utilized ligand libraries consisting of environmental and cellular metabolic compounds, and fluorescence thermal shift based high throughput ligand binding screens. This process resulted in the identification of specific binding ligands for approximately 64% of the purified and screened proteins. The collection of binding ligands is representative of common functionalities associated with many bacterial organisms as well as specific capabilities linked to the ecological niche occupied by R. palustris. Conclusion: The functional screen identified specific ligands that bound to ABC transporter periplasmic binding subunits from R. palustris. These assignments provide unique insight for the metabolic capabilities of this organism and are consistent with the ecological niche of strain isolation. This functional insight can be used to improve the annotation of related organisms and provides a route to evaluate the evolution of this important and diverse group of transporter proteins.« less

The Effects of a Systematically Designed Online Learning Environment on Preservice Teachers' Professional Knowledge

ERIC Educational Resources Information Center

Evens, Marie; Larmuseau, Charlotte; Dewaele, Katrien; Van Craesbeek, Leen; Elen, Jan; Depaepe, Fien

2017-01-01

This study examines the effects of an online learning environment on preservice teachers' pedagogical content knowledge (PCK), content knowledge (CK) (related to French in primary teacher education), and pedagogical knowledge (PK) in a quasi-experimental design. More specifically, the following research question is addressed: Is a systematically…

Mechanical stress regulation of plant growth and development

NASA Technical Reports Server (NTRS)

Mitchell, C. A.; Myers, P. N.

1995-01-01

The authors introduce the chapter with a discussion of lessons from nature, agriculture, and landscapes; terms and definitions; and an historical perspective of mechanical stress regulation of plant growth and development. Topics include developmental responses to mechanical stress; mechanical stress-environment interactions; metabolic, productivity, and compositional changes; hormonal involvement; mechanoperception and early transduction mechanisms; applications in agriculture; and research implications. The discussion of hormonal involvement in mechanical stress physiology includes ethylene, auxin, gibberellins, and other phytohormones. The discussion of applications in agriculture examines windbreaks, nursery practices, height control and conditioning, and enhancement of growth and productivity. Implications for research are related to handling plant materials, space biology, and future research needs.

Hierarchical signaling transduction of the immune and muscle cell crosstalk in muscle regeneration.

PubMed

Yang, Wenjun; Hu, Ping

2018-04-01

The muscle regeneration is a complicated bioprocess that involved in many cell types, including necrotic muscle cells, satellite cells, mesenchymal cells, pericytes, immune cells, and other cell types present at the injury site. Immune cells involved in both innate and adaptive immune responses regulate the progress of muscle regeneration. In this review, we discussed the roles of different immune cells in muscle regeneration. The immune cells regulate muscle regeneration through cytokine production, cell-cell contacts, and general immune environment regulation. We also describe the current known mechanism of how immune cells regulating muscle regeneration. Copyright © 2017. Published by Elsevier Inc.

Wires in the soup: quantitative models of cell signaling

PubMed Central

Cheong, Raymond; Levchenko, Andre

2014-01-01

Living cells are capable of extracting information from their environments and mounting appropriate responses to a variety of associated challenges. The underlying signal transduction networks enabling this can be quite complex, necessitating for their unraveling by sophisticated computational modeling coupled with precise experimentation. Although we are still at the beginning of this process, some recent examples of integrative analysis of cell signaling are very encouraging. This review highlights the case of the NF-κB pathway in order to illustrate how a quantitative model of a signaling pathway can be gradually constructed through continuous experimental validation, and what lessons one might learn from such exercises. PMID:18291655

Attempts on producing lymphoid cell line from Penaeus monodon by induction with SV40-T and 12S EIA oncogenes.

PubMed

Puthumana, Jayesh; Prabhakaran, Priyaja; Philip, Rosamma; Singh, I S Bright

2015-12-01

In an attempt of in vitro transformation, transfection mediated expression of Simian virus-40 (T) antigen (SV40-T) and transduction mediated expression of Adenovirus type 12 early region 1A (12S E1A) oncogene were performed in Penaeus monodon lymphoid cells. pSV3-neo vector encoding SV40-T oncogene and a recombinant baculovirus BacP2-12S E1A-GFP encoding 12S E1A oncogene under the control of hybrid promoters were used. Electroporation and lipofection mediated transformation of SV40-T in lymphoid cells confirmed the transgene expression by phenotypic variation and the expression of GFP in co-transfection experiment. The cells transfected by lipofection (≥ 5%) survived for 14 days with lower toxicity (30%), whilst on electroporation, most of the cells succumbed to death (60%) and survived cells lived up to 7 days. Transduction efficiency in primary lymphoid cells was more than 80% within 14 days of post-transduction, however, an incubation period of 7 days post-transduction was observed without detectable expression of 12S E1A. High level of oncogenic 12S E1A expression were observed after 14 day post-transduction and the proliferating cells survived for more than 90 days with GFP expression, however, without in vitro transformation and immortalization. The study put forth the requirement of transduction mediated 'specific' oncogene expression along with telomerase activation and epigenetic induction for the immortalization and establishment of shrimp cell line. Copyright © 2015. Published by Elsevier Ltd.

Gene transduction in mammalian cells using Bombyx mori nucleopolyhedrovirus assisted by glycoprotein 64 of Autographa californica multiple nucleopolyhedrovirus.

PubMed

Kato, Tatsuya; Sugioka, Saki; Itagaki, Kohei; Park, Enoch Y

2016-08-26

Autographa californica multiple nucleopolyhedrovirus (AcMNPV), an alphabaculovirus, has been widely utilized for protein expression in not only insect cells but also mammalian cells. AcMNPV is closely related to Bombyx mori nucleopolyhedrovirus (BmNPV), and nucleotide sequences of AcMNPV genes have high similarity with those of BmNPV. However, the transduction of BmNPV into mammalian cells has not been reported. In this study, we constructed a recombinant BmNPV (BmNPVΔbgp/AcGP64/EGFP) whose surface 64 kDa glycoprotein (BmGP64) was substituted with that from AcMNPV (AcGP64). BmNPVΔbgp/AcGP64/EGFP also carried an EGFP gene under the control of the CMV promoter. BmNPVΔbgp/AcGP64/EGFP successfully transduced HEK293T cells. In comparison, a control construct (BmNPVΔbgp/BmGP64/EGFP) which possessed BmGP64 instead of AcGP64 did not express EGFP in HEK293T cells. The transduction efficiency of BmNPVΔbgp/AcGP64/EGFP was lower than that of an AcMNPV based-BacMam GFP transduction control. This result indicates that AcGP64 facilitates BmNPV transduction into HEK293T cells. BmNPV can be prepared easily on a large scale because BmNPV can infect silkworm larvae without any special equipment, even though specific diet is needed for silkworm rearing. BmNPV gene transduction into mammalian cells can potentially be applied easily for gene delivery into mammalian cells.

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

PubMed

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 (P<0.0001). MRP-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 (P<0.0001). However, no difference was observed in the expression of Arp2, Arp3 or other WASPs. A neutralizing anti-MRP-1/CD9 monoclonal antibody inhibited downregulation of WAVE2 in MRP-1/CD9-transfected HT1080 cells (P<0.0001), and reversed the morphological effects of MRP-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.

A novel semi-transductive learning framework for efficient atypicality detection in chest radiographs

NASA Astrophysics Data System (ADS)

Alzubaidi, Mohammad; Balasubramanian, Vineeth; Patel, Ameet; Panchanathan, Sethuraman; Black, John A., Jr.

2012-03-01

Inductive learning refers to machine learning algorithms that learn a model from a set of training data instances. Any test instance is then classified by comparing it to the learned model. When the set of training instances lend themselves well to modeling, the use of a model substantially reduces the computation cost of classification. However, some training data sets are complex, and do not lend themselves well to modeling. Transductive learning refers to machine learning algorithms that classify test instances by comparing them to all of the training instances, without creating an explicit model. This can produce better classification performance, but at a much higher computational cost. Medical images vary greatly across human populations, constituting a data set that does not lend itself well to modeling. Our previous work showed that the wide variations seen across training sets of "normal" chest radiographs make it difficult to successfully classify test radiographs with an inductive (modeling) approach, and that a transductive approach leads to much better performance in detecting atypical regions. The problem with the transductive approach is its high computational cost. This paper develops and demonstrates a novel semi-transductive framework that can address the unique challenges of atypicality detection in chest radiographs. The proposed framework combines the superior performance of transductive methods with the reduced computational cost of inductive methods. Our results show that the proposed semitransductive approach provides both effective and efficient detection of atypical regions within a set of chest radiographs previously labeled by Mayo Clinic expert thoracic radiologists.

Ca2+-sensors and ROS-GC: interlocked sensory transduction elements: a review

PubMed Central

Sharma, Rameshwar K.; Duda, Teresa

2012-01-01

From its initial discovery that ROS-GC membrane guanylate cyclase is a mono-modal Ca2+-transduction system linked exclusively with the photo-transduction machinery to the successive finding that it embodies a remarkable bimodal Ca2+ signaling device, its widened transduction role in the general signaling mechanisms of the sensory neuron cells was envisioned. A theoretical concept was proposed where Ca2+-modulates ROS-GC through its generated cyclic GMP via a nearby cyclic nucleotide gated channel and creates a hyper- or depolarized sate in the neuron membrane (Ca2+ Binding Proteins 1:1, 7–11, 2006). The generated electric potential then becomes a mode of transmission of the parent [Ca2+]i signal. Ca2+ and ROS-GC are interlocked messengers in multiple sensory transduction mechanisms. This comprehensive review discusses the developmental stages to the present status of this concept and demonstrates how neuronal Ca2+-sensor (NCS) proteins are the interconnected elements of this elegant ROS-GC transduction system. The focus is on the dynamism of the structural composition of this system, and how it accommodates selectivity and elasticity for the Ca2+ signals to perform multiple tasks linked with the SENSES of vision, smell, and possibly of taste and the pineal gland. An intriguing illustration is provided for the Ca2+ sensor GCAP1 which displays its remarkable ability for its flexibility in function from being a photoreceptor sensor to an odorant receptor sensor. In doing so it reverses its function from an inhibitor of ROS-GC to the stimulator of ONE-GC membrane guanylate cyclase. PMID:22509149

Efficient Transduction of Human and Rhesus Macaque Primary T Cells by a Modified Human Immunodeficiency Virus Type 1-Based Lentiviral Vector.

PubMed

He, Huan; Xue, Jing; Wang, Weiming; Liu, Lihong; Ye, Chaobaihui; Cong, Zhe; Kimata, Jason T; Qin, Chuan; Zhou, Paul

2017-03-01

Human immunodeficiency virus type 1 (HIV-1)-based lentiviral vectors efficiently transduce genes to human, but not rhesus, primary T cells and hematopoietic stem cells (HSCs). The poor transduction of HIV-1 vectors to rhesus cells is mainly due to species-specific restriction factors such as rhesus TRIM5α. Previously, several strategies to modify HIV-1 vectors were developed to overcome rhesus TRIM5α restriction. While the modified HIV-1 vectors efficiently transduce rhesus HSCs, they remain suboptimal for rhesus primary T cells. Recently, HIV-1 variants that encode combinations of LNEIE mutations in capsid (CA) protein and SIVmac239 Vif were found to replicate efficiently in rhesus primary T cells. Thus, the present study tested whether HIV-1 vectors packaged by a packaging construct containing these CA substitutions could efficiently transduce both human and rhesus primary CD4 T cells. To accomplish this, LNEIE mutations were made in the packaging construct CEMΔ8.9, and recombinant HIV-1 vectors packaged by Δ8.9 WT or Δ8.9 LNEIE were generated. Transduction rates, CA stability, and vector integration in CEMss-CCR5 and CEMss-CCR5-rhTRIM5α/green fluorescent protein cells, as well as transduction rates in human and rhesus primary CD4 T cells by Δ8.9 WT or Δ8.9 LNEIE-packaged HIV-1 vectors, were compared. Finally, the influence of rhesus TRIM5α variations in transduction rates to primary CD4 T cells from a cohort of 37 Chinese rhesus macaques was studied. While it maintains efficient transduction for human T-cell line and primary CD4 T cells, Δ8.9 LNEIE-packaged HIV-1 vector overcomes rhesus TRIM5α-mediated CA degradation, resulting in significantly higher transduction efficiency of rhesus primary CD4 T cells than Δ8.9 WT-packaged HIV-1 vector. Rhesus TRIM5α variations strongly influence transduction efficiency of rhesus primary CD4 T cells by both Δ8.9 WT or Δ8.9 LNEIE-packaged HIV-1 vectors. Thus, it is concluded that Δ8.9 LNEIE-packaged HIV-1 vector overcomes rhesus TRIM5α restriction and efficiently transduces both human and rhesus primary T cells.

Enhanced Central Nervous System Transduction with Lentiviral Vectors Pseudotyped with RVG/HIV-1gp41 Chimeric Envelope Glycoproteins

PubMed Central

Trabalza, Antonio; Eleftheriadou, Ioanna; Sgourou, Argyro; Liao, Ting-Yi; Patsali, Petros; Lee, Heyne

2014-01-01

ABSTRACT To investigate the potential benefits which may arise from pseudotyping the HIV-1 lentiviral vector with its homologous gp41 envelope glycoprotein (GP) cytoplasmic tail (CT), we created chimeric RVG/HIV-1gp41 GPs composed of the extracellular and transmembrane sequences of RVG and either the full-length gp41 CT or C terminus gp41 truncations sequentially removing existing conserved motifs. Lentiviruses (LVs) pseudotyped with the chimeric GPs were evaluated in terms of particle release (physical titer), biological titers, infectivity, and in vivo central nervous system (CNS) transduction. We report here that LVs carrying shorter CTs expressed higher levels of envelope GP and showed a higher average infectivity than those bearing full-length GPs. Interestingly, complete removal of GP CT led to vectors with the highest transduction efficiency. Removal of all C-terminal gp41 CT conserved motifs, leaving just 17 amino acids (aa), appeared to preserve infectivity and resulted in a significantly increased physical titer. Furthermore, incorporation of these 17 aa in the RVG CT notably enhanced the physical titer. In vivo stereotaxic delivery of LV vectors exhibiting the best in vitro titers into rodent striatum facilitated efficient transduction of the CNS at the site of injection. A particular observation was the improved retrograde transduction of neurons in connected distal sites that resulted from the chimeric envelope R5 which included the “Kennedy” sequence (Ken) and lentivirus lytic peptide 2 (LLP2) conserved motifs in the CT, and although it did not exhibit a comparable high titer upon pseudotyping, it led to a significant increase in distal retrograde transduction of neurons. IMPORTANCE In this study, we have produced novel chimeric envelopes bearing the extracellular domain of rabies fused to the cytoplasmic tail (CT) of gp41 and pseudotyped lentiviral vectors with them. Here we report novel effects on the transduction efficiency and physical titer of these vectors, depending on CT length and context. We also managed to achieve increased neuronal transduction in vivo in the rodent CNS, thus demonstrating that the efficiency of these vectors can be enhanced following merely CT manipulation. We believe that this paper is a novel contribution to the field and opens the way for further attempts to surface engineer lentiviral vectors and make them more amenable for applications in human disease. PMID:24371049

Efficient Transduction of Human and Rhesus Macaque Primary T Cells by a Modified Human Immunodeficiency Virus Type 1–Based Lentiviral Vector

PubMed Central

He, Huan; Xue, Jing; Wang, Weiming; Liu, Lihong; Ye, Chaobaihui; Cong, Zhe; Kimata, Jason T.; Qin, Chuan; Zhou, Paul

2017-01-01

Human immunodeficiency virus type 1 (HIV-1)-based lentiviral vectors efficiently transduce genes to human, but not rhesus, primary T cells and hematopoietic stem cells (HSCs). The poor transduction of HIV-1 vectors to rhesus cells is mainly due to species-specific restriction factors such as rhesus TRIM5α. Previously, several strategies to modify HIV-1 vectors were developed to overcome rhesus TRIM5α restriction. While the modified HIV-1 vectors efficiently transduce rhesus HSCs, they remain suboptimal for rhesus primary T cells. Recently, HIV-1 variants that encode combinations of LNEIE mutations in capsid (CA) protein and SIVmac239 Vif were found to replicate efficiently in rhesus primary T cells. Thus, the present study tested whether HIV-1 vectors packaged by a packaging construct containing these CA substitutions could efficiently transduce both human and rhesus primary CD4 T cells. To accomplish this, LNEIE mutations were made in the packaging construct CEMΔ8.9, and recombinant HIV-1 vectors packaged by Δ8.9 WT or Δ8.9 LNEIE were generated. Transduction rates, CA stability, and vector integration in CEMss-CCR5 and CEMss-CCR5-rhTRIM5α/green fluorescent protein cells, as well as transduction rates in human and rhesus primary CD4 T cells by Δ8.9 WT or Δ8.9 LNEIE-packaged HIV-1 vectors, were compared. Finally, the influence of rhesus TRIM5α variations in transduction rates to primary CD4 T cells from a cohort of 37 Chinese rhesus macaques was studied. While it maintains efficient transduction for human T-cell line and primary CD4 T cells, Δ8.9 LNEIE-packaged HIV-1 vector overcomes rhesus TRIM5α-mediated CA degradation, resulting in significantly higher transduction efficiency of rhesus primary CD4 T cells than Δ8.9 WT-packaged HIV-1 vector. Rhesus TRIM5α variations strongly influence transduction efficiency of rhesus primary CD4 T cells by both Δ8.9 WT or Δ8.9 LNEIE-packaged HIV-1 vectors. Thus, it is concluded that Δ8.9 LNEIE-packaged HIV-1 vector overcomes rhesus TRIM5α restriction and efficiently transduces both human and rhesus primary T cells. PMID:28042947

Emerging Knowledge of Distant Environments: An International Study of Four and Six Year Olds in England, Slovenia and Greece.

ERIC Educational Resources Information Center

Palmer, Joy; Suggate, Jennifer; Bajd, Barbara; Tsaliki, Elisavel; Duraki, Danica; Paraskevopoulos, Stephanos; Razpet, Nada; Dimec, Darja Skribe

1999-01-01

Investigated the nature and origins of early ideas about the environment held by children. Found that data explain aspects of the knowledge children have about various environments before they enter school, the development of this knowledge from ages 4 to 6, and young children's developing understanding of the impacts of environmental changes.…

Engineering AAV receptor footprints for gene therapy.

PubMed

Madigan, Victoria J; Asokan, Aravind

2016-06-01

Adeno-associated viruses (AAV) are currently at the forefront of human gene therapy clinical trials as recombinant vectors. Significant progress has been made in elucidating the structure, biology and tropisms of different naturally occurring AAV isolates in the past decade. In particular, a spectrum of AAV capsid interactions with host receptors have been identified and characterized. These studies have enabled a better understanding of key determinants of AAV cell recognition and entry in different hosts. This knowledge is now being applied toward engineering new, lab-derived AAV capsids with favorable transduction profiles. The current review conveys a structural perspective of capsid-glycan interactions and provides a roadmap for generating synthetic strains by engineering AAV receptor footprints. Copyright © 2016 Elsevier B.V. All rights reserved.

An Object-Oriented Software Architecture for the Explorer-2 Knowledge Management Environment

PubMed Central

Tarabar, David B.; Greenes, Robert A.; Slosser, Eric T.

1989-01-01

Explorer-2 is a workstation based environment to facilitate knowledge management. It provides consistent access to a broad range of knowledge on the basis of purpose, not type. We have developed a software architecture based on Object-Oriented programming for Explorer-2. We have defined three classes of program objects: Knowledge ViewFrames, Knowledge Resources, and Knowledge Bases. This results in knowledge management at three levels: the screen level, the disk level and the meta-knowledge level. We have applied this design to several knowledge bases, and believe that there is a broad applicability of this design.

An Approach for Externalization of Expert Tacit Knowledge Using a Query Management System in an E-Learning Environment

ERIC Educational Resources Information Center

Khan, Abdul Azeez; Khader, Sheik Abdul

2014-01-01

E-learning or electronic learning platforms facilitate delivery of the knowledge spectrum to the learning community through information and communication technologies. The transfer of knowledge takes place from experts to learners, and externalization of the knowledge transfer is significant. In the e-learning environment, the learners seek…

The Knowledge Development Model: Responding to the Changing Landscape of Learning in Virtual Environments

ERIC Educational Resources Information Center

Adams, Nan B.

2017-01-01

Society's relationship to knowledge and what is considered to be factual is changing. Effective teaching models focused on leveraging strategic control of the knowledge from teachers to learners in virtual learning environments are critical to insuring a positive path is charted. The Knowledge Development Model serves as the guide for determining…

Modelling protein functional domains in signal transduction using Maude

NASA Technical Reports Server (NTRS)

Sriram, M. G.

2003-01-01

Modelling of protein-protein interactions in signal transduction is receiving increased attention in computational biology. This paper describes recent research in the application of Maude, a symbolic language founded on rewriting logic, to the modelling of functional domains within signalling proteins. Protein functional domains (PFDs) are a critical focus of modern signal transduction research. In general, Maude models can simulate biological signalling networks and produce specific testable hypotheses at various levels of abstraction. Developing symbolic models of signalling proteins containing functional domains is important because of the potential to generate analyses of complex signalling networks based on structure-function relationships.

The effect of the inner-hair-cell mediated transduction on the shape of neural tuning curves

NASA Astrophysics Data System (ADS)

Altoè, Alessandro; Pulkki, Ville; Verhulst, Sarah

2018-05-01

The inner hair cells of the mammalian cochlea transform the vibrations of their stereocilia into releases of neurotransmitter at the ribbon synapses, thereby controlling the activity of the afferent auditory fibers. The mechanical-to-neural transduction is a highly nonlinear process and it introduces differences between the frequency-tuning of the stereocilia and that of the afferent fibers. Using a computational model of the inner hair cell that is based on in vitro data, we estimated that smaller vibrations of the stereocilia are necessary to drive the afferent fibers above threshold at low (≤0.5 kHz) than at high (≥4 kHz) driving frequencies. In the base of the cochlea, the transduction process affects the low-frequency tails of neural tuning curves. In particular, it introduces differences between the frequency-tuning of the stereocilia and that of the auditory fibers resembling those between basilar membrane velocity and auditory fibers tuning curves in the chinchilla base. For units with a characteristic frequency between 1 and 4 kHz, the transduction process yields shallower neural than stereocilia tuning curves as the characteristic frequency decreases. This study proposes that transduction contributes to the progressive broadening of neural tuning curves from the base to the apex.

Ultramicroscopy as a novel tool to unravel the tropism of AAV gene therapy vectors in the brain.

PubMed

Alves, Sandro; Bode, Julia; Bemelmans, Alexis-Pierre; von Kalle, Christof; Cartier, Nathalie; Tews, Björn

2016-06-20

Recombinant adeno-associated viral (AAV) vectors have advanced to the vanguard of gene therapy. Numerous naturally occurring serotypes have been used to target cells in various tissues. There is a strong need for fast and dynamic methods which efficiently unravel viral tropism in whole organs. Ultramicroscopy (UM) is a novel fluorescence microscopy technique that images optically cleared undissected specimens, achieving good resolutions at high penetration depths while being non-destructive. UM was applied to obtain high-resolution 3D analysis of AAV transduction in adult mouse brains, especially in the hippocampus, a region of interest for Alzheimer's disease therapy. We separately or simultaneously compared transduction efficacies for commonly used serotypes (AAV9 and AAVrh10) using fluorescent reporter expression. We provide a detailed comparative and quantitative analysis of the transduction profiles. UM allowed a rapid analysis of marker fluorescence expression in neurons with intact projections deep inside the brain, in defined anatomical structures. Major hippocampal neuronal transduction was observed with both vectors, with slightly better efficacy for AAV9 in UM. Glial response and synaptic marker expression did not change post transduction.We propose UM as a novel valuable complementary tool to efficiently and simultaneously unravel tropism of different viruses in a single non-dissected adult rodent brain.

High-Efficiency Promoter-Dependent Transduction by Adeno-Associated Virus Type 6 Vectors in Mouse Lung

PubMed Central

HALBERT, CHRISTINE L.; LAM, SIU-LING; MILLER, A. DUSTY

2014-01-01

The transduction efficiency of adeno-associated virus (AAV) vectors in various somatic tissues has been shown to depend heavily on the AAV type from which the vector capsid proteins are derived. Among the AAV types studied, AAV6 efficiently transduces cells of the airway epithelium, making it a good candidate for the treatment of lung diseases such as cystic fibrosis. Here we have evaluated the effects of various promoter sequences on transduction rates and gene expression levels in the lung. Of the strong viral promoters examined, the Rous sarcoma virus (RSV) promoter performed significantly better than a human cytomegalovirus (CMV) promoter in the airway epithelium. However, a hybrid promoter consisting of a CMV enhancer, β-actin promoter and splice donor, and a β-globin splice acceptor (CAG promoter) exhibited even higher expression than either of the strong viral promoters alone, showing a 38-fold increase in protein expression over the RSV promoter. In addition, we show that vectors containing either the RSV or CAG promoter expressed well in the nasal and tracheal epithelium. Transduction rates in the 90% range were achieved in many airways with the CAG promoter, showing that with the proper AAV capsid proteins and promoter sequences, highly efficient transduction can be achieved. PMID:17430088

Blood-brain barrier shuttle peptides enhance AAV transduction in the brain after systemic administration.

PubMed

Zhang, Xintao; He, Ting; Chai, Zheng; Samulski, R Jude; Li, Chengwen

2018-09-01

The adeno-associated virus (AAV) vector has been used in preclinical and clinical trials of gene therapy for central nervous system (CNS) diseases. One of the biggest challenges of effectively delivering AAV to the brain is to surmount the blood-brain barrier (BBB). Herein, we identified several potential BBB shuttle peptides that significantly enhanced AAV8 transduction in the brain after a systemic administration, the best of which was the THR peptide. The enhancement of AAV8 brain transduction by THR is dose-dependent, and neurons are the primary THR targets. Mechanism studies revealed that THR directly bound to the AAV8 virion, increasing its ability to cross the endothelial cell barrier. Further experiments showed that binding of THR to the AAV virion did not interfere with AAV8 infection biology, and that THR competitively blocked transferrin from binding to AAV8. Taken together, our results demonstrate, for the first time, that BBB shuttle peptides are able to directly interact with AAV and increase the ability of the AAV vectors to cross the BBB for transduction enhancement in the brain. These results will shed important light on the potential applications of BBB shuttle peptides for enhancing brain transduction with systemic administration of AAV vectors. Copyright © 2018 Elsevier Ltd. All rights reserved.

Suffering What They Must: The Shifting Alliances of Romania and Finland in World War II

DTIC Science & Technology

2015-05-01

operational artist considers these theories in understanding an environment. However, the military planner then must apply that knowledge to...understanding a specific strategic environment, and then translate that knowledge into conceptual and detailed plans for military operations. The stories of...situation where military planners of a small nation could leverage their knowledge of a strategic environment to anticipate change and plan accordingly

The home environment: A mediator of nutrition knowledge and diet quality in adolescents.

PubMed

Tabbakh, Tamara; Freeland-Graves, Jean H

2016-10-01

The objective of this research was to assess adherence to the Healthy Eating Index-2010 of mothers and their adolescents (11-14 years old) and to examine the role of the home environment as a mediator of maternal nutrition knowledge and adolescent diet quality. It is hypothesized that mothers with greater knowledge impact the diet quality of their adolescents by creation of healthier home environments. A sample of 206 mother-adolescent dyads separately completed the Multidimensional Home Environment Scale, a Food Frequency Questionnaire, and a Nutrition Knowledge Scale. Body mass index-for-age percentiles were derived from weight and height measurements obtained by researcher; diet quality was estimated via the Healthy Eating Index (HEI)-2010. Percent of maximum score on nutrition knowledge for both mothers and adolescents were poor, with lowest scores on recommendations of healthy eating and physical activity (48% and 19%, respectively). A model of maternal nutrition knowledge (independent variable) and adolescent diet quality (dependent variable) indicated that greater knowledge was associated with higher scores on total fruit (p = 0.02), whole grains (p = 0.05), seafood and plant proteins (p = 0.01), and overall diet quality (p < 0.01), as well as lower scores on empty calories (p = 0.01). Inclusion of the home environment as a mediator yielded significant estimates of the indirect effect (β = 0.61, 95% CI: 0.3-1.0). Within the home environment, psychological (β = 0.46), social (β = 0.23), and environmental (β = 0.65) variables were all significant mediators of nutrition knowledge on diet quality. These results emphasize the importance of maternal nutrition knowledge and the mediating effect of the home environment on the diet quality of adolescents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Emergent adaptive behaviour of GRN-controlled simulated robots in a changing environment.

PubMed

Yao, Yao; Storme, Veronique; Marchal, Kathleen; Van de Peer, Yves

2016-01-01

We developed a bio-inspired robot controller combining an artificial genome with an agent-based control system. The genome encodes a gene regulatory network (GRN) that is switched on by environmental cues and, following the rules of transcriptional regulation, provides output signals to actuators. Whereas the genome represents the full encoding of the transcriptional network, the agent-based system mimics the active regulatory network and signal transduction system also present in naturally occurring biological systems. Using such a design that separates the static from the conditionally active part of the gene regulatory network contributes to a better general adaptive behaviour. Here, we have explored the potential of our platform with respect to the evolution of adaptive behaviour, such as preying when food becomes scarce, in a complex and changing environment and show through simulations of swarm robots in an A-life environment that evolution of collective behaviour likely can be attributed to bio-inspired evolutionary processes acting at different levels, from the gene and the genome to the individual robot and robot population.

Emergent adaptive behaviour of GRN-controlled simulated robots in a changing environment

PubMed Central

Yao, Yao; Storme, Veronique; Marchal, Kathleen

2016-01-01

We developed a bio-inspired robot controller combining an artificial genome with an agent-based control system. The genome encodes a gene regulatory network (GRN) that is switched on by environmental cues and, following the rules of transcriptional regulation, provides output signals to actuators. Whereas the genome represents the full encoding of the transcriptional network, the agent-based system mimics the active regulatory network and signal transduction system also present in naturally occurring biological systems. Using such a design that separates the static from the conditionally active part of the gene regulatory network contributes to a better general adaptive behaviour. Here, we have explored the potential of our platform with respect to the evolution of adaptive behaviour, such as preying when food becomes scarce, in a complex and changing environment and show through simulations of swarm robots in an A-life environment that evolution of collective behaviour likely can be attributed to bio-inspired evolutionary processes acting at different levels, from the gene and the genome to the individual robot and robot population. PMID:28028477

Intervention of electroacupuncture on spinal p38 MAPK/ATF-2/VR-1 pathway in treating inflammatory pain induced by CFA in rats.

PubMed

Fang, Jian-Qiao; Du, Jun-Ying; Liang, Yi; Fang, Jun-Fan

2013-03-22

Previous studies have demonstrated that p38 MAPK signal transduction pathway plays an important role in the development and maintenance of inflammatory pain. Electroacupuncture (EA) can suppress the inflammatory pain. However, the relationship between EA effect and p38 MAPK signal transduction pathway in inflammatory pain remains poorly understood. It is our hypothesis that p38 MAPK/ATF-2/VR-1 and/or p38 MAPK/ATF-2/COX-2 signal transduction pathway should be activated by inflammatory pain in CFA-injected model. Meanwhile, EA may inhibit the activation of p38 MAPK signal transduction pathway. The present study aims to investigate that anti-inflammatory and analgesic effect of EA and its intervention on the p38 MAPK signal transduction pathway in a rat model of inflammatory pain. EA had a pronounced anti-inflammatory and analgesic effect on CFA-induced chronic inflammatory pain in rats. EA could quickly raise CFA-rat's paw withdrawal thresholds (PWTs) and maintain good and long analgesic effect, while it subdued the ankle swelling of CFA rats only at postinjection day 14. EA could down-regulate the protein expressions of p-p38 MAPK and p-ATF-2, reduced the numbers of p-p38 MAPK-IR cells and p-ATF-2-IR cells in spinal dorsal horn in CFA rats, inhibited the expressions of both protein and mRNA of VR-1, but had no effect on the COX-2 mRNA expression. The present study indicates that inhibiting the activation of spinal p38 MAPK/ATF-2/VR-1 pathway may be one of the main mechanisms via central signal transduction pathway in the process of anti-inflammatory pain by EA in CFA rats.

Quantitative Biology of Exercise-Induced Signal Transduction Pathways.

PubMed

Liu, Timon Cheng-Yi; Liu, Gang; Hu, Shao-Juan; Zhu, Ling; Yang, Xiang-Bo; Zhang, Quan-Guang

2017-01-01

Exercise is essential in regulating energy metabolism. Exercise activates cellular, molecular, and biochemical pathways with regulatory roles in training response adaptation. Among them, endurance/strength training of an individual has been shown to activate its respective signal transduction pathways in skeletal muscle. This was further studied from the viewpoint of quantitative difference (QD). For the mean values, [Formula: see text], of two sets of data, their QD is defined as [Formula: see text] ([Formula: see text]). The function-specific homeostasis (FSH) of a function of a biosystem is a negative-feedback response of the biosystem to maintain the function-specific conditions inside the biosystem so that the function is perfectly performed. A function in/far from its FSH is called a normal/dysfunctional function. A cellular normal function can resist the activation of other signal transduction pathways so that there are normal function-specific signal transduction pathways which full activation maintains the normal function. An acute endurance/strength training may be dysfunctional, but its regular training may be normal. The normal endurance/strength training of an individual may resist the activation of other signal transduction pathways in skeletal muscle so that there may be normal endurance/strength training-specific signal transduction pathways (NEPs/NSPs) in skeletal muscle. The endurance/strength training may activate NSPs/NEPs, but the QD from the control is smaller than 0.80. The simultaneous activation of both NSPs and NEPs may enhance their respective activation, and the QD from the control is larger than 0.80. The low level laser irradiation pretreatment of rats may promote the activation of NSPs in endurance training skeletal muscle. There may be NEPs/NSPs in skeletal muscle trained by normal endurance/strength training.

Lipid Partitioning, Incomplete Fatty Acid Oxidation, and Insulin Signal Transduction in Primary Human Muscle Cells: Effects of Severe Obesity, Fatty Acid Incubation, and Fatty Acid Translocase/CD36 Overexpression

PubMed Central

Bell, Jill A.; Reed, Melissa A.; Consitt, Leslie A.; Martin, Ola J.; Haynie, Kimberly R.; Hulver, Matthew W.; Muoio, Deborah M.; Dohm, G. Lynis

2010-01-01

Context: Intracellular lipid partitioning toward storage and the incomplete oxidation of fatty acids (FA) have been linked to insulin resistance. Objective: To gain insight into how intracellular lipid metabolism is related to insulin signal transduction, we examined the effects of severe obesity, excess FA, and overexpression of the FA transporter, FA translocase (FAT)/CD36, in primary human skeletal myocytes. Design, Setting, and Patients: Insulin signal transduction, FA oxidation, and metabolism were measured in skeletal muscle cells harvested from lean and severely obese women. To emulate the obesity phenotype in our cell culture system, we incubated cells from lean individuals with excess FA or overexpressed FAT/CD36 using recombinant adenoviral technology. Results: Complete oxidation of FA was significantly reduced, whereas total lipid accumulation, FA esterification into lipid intermediates, and incomplete oxidation were up-regulated in the muscle cells of severely obese subjects. Insulin signal transduction was reduced in the muscle cells from severely obese subjects compared to lean controls. Incubation of muscle cells from lean subjects with lipids reduced insulin signal transduction and increased lipid storage and incomplete FA oxidation. CD36 overexpression increased FA transport capacity, but did not impair complete FA oxidation and insulin signal transduction in muscle cells from lean subjects. Conclusions: Cultured myocytes from severely obese women express perturbations in FA metabolism and insulin signaling reminiscent of those observed in vivo. The obesity phenotype can be recapitulated in muscle cells from lean subjects via exposure to excess lipid, but not by overexpressing the FAT/CD36 FA transporter. PMID:20427507

Intervention of electroacupuncture on spinal p38 MAPK/ATF-2/VR-1 pathway in treating inflammatory pain induced by CFA in rats

PubMed Central

2013-01-01

Background Previous studies have demonstrated that p38 MAPK signal transduction pathway plays an important role in the development and maintenance of inflammatory pain. Electroacupuncture (EA) can suppress the inflammatory pain. However, the relationship between EA effect and p38 MAPK signal transduction pathway in inflammatory pain remains poorly understood. It is our hypothesis that p38 MAPK/ATF-2/VR-1 and/or p38 MAPK/ATF-2/COX-2 signal transduction pathway should be activated by inflammatory pain in CFA-injected model. Meanwhile, EA may inhibit the activation of p38 MAPK signal transduction pathway. The present study aims to investigate that anti-inflammatory and analgesic effect of EA and its intervention on the p38 MAPK signal transduction pathway in a rat model of inflammatory pain. Results EA had a pronounced anti-inflammatory and analgesic effect on CFA-induced chronic inflammatory pain in rats. EA could quickly raise CFA-rat’s paw withdrawal thresholds (PWTs) and maintain good and long analgesic effect, while it subdued the ankle swelling of CFA rats only at postinjection day 14. EA could down-regulate the protein expressions of p-p38 MAPK and p-ATF-2, reduced the numbers of p-p38 MAPK-IR cells and p-ATF-2-IR cells in spinal dorsal horn in CFA rats, inhibited the expressions of both protein and mRNA of VR-1, but had no effect on the COX-2 mRNA expression. Conclusions The present study indicates that inhibiting the activation of spinal p38 MAPK/ATF-2/VR-1 pathway may be one of the main mechanisms via central signal transduction pathway in the process of anti-inflammatory pain by EA in CFA rats. PMID:23517865

Construction of dynamic stochastic simulation models using knowledge-based techniques

NASA Technical Reports Server (NTRS)

Williams, M. Douglas; Shiva, Sajjan G.

1990-01-01

Over the past three decades, computer-based simulation models have proven themselves to be cost-effective alternatives to the more structured deterministic methods of systems analysis. During this time, many techniques, tools and languages for constructing computer-based simulation models have been developed. More recently, advances in knowledge-based system technology have led many researchers to note the similarities between knowledge-based programming and simulation technologies and to investigate the potential application of knowledge-based programming techniques to simulation modeling. The integration of conventional simulation techniques with knowledge-based programming techniques is discussed to provide a development environment for constructing knowledge-based simulation models. A comparison of the techniques used in the construction of dynamic stochastic simulation models and those used in the construction of knowledge-based systems provides the requirements for the environment. This leads to the design and implementation of a knowledge-based simulation development environment. These techniques were used in the construction of several knowledge-based simulation models including the Advanced Launch System Model (ALSYM).

Gene Networks Involved in Hormonal Control of Root Development in Arabidopsis thaliana: A Framework for Studying Its Disturbance by Metal Stress

PubMed Central

De Smet, Stefanie; Cuypers, Ann; Vangronsveld, Jaco; Remans, Tony

2015-01-01

Plant survival under abiotic stress conditions requires morphological and physiological adaptations. Adverse soil conditions directly affect root development, although the underlying mechanisms remain largely to be discovered. Plant hormones regulate normal root growth and mediate root morphological responses to abiotic stress. Hormone synthesis, signal transduction, perception and cross-talk create a complex network in which metal stress can interfere, resulting in root growth alterations. We focus on Arabidopsis thaliana, for which gene networks in root development have been intensively studied, and supply essential terminology of anatomy and growth of roots. Knowledge of gene networks, mechanisms and interactions related to the role of plant hormones is reviewed. Most knowledge has been generated for auxin, the best-studied hormone with a pronounced primary role in root development. Furthermore, cytokinins, gibberellins, abscisic acid, ethylene, jasmonic acid, strigolactones, brassinosteroids and salicylic acid are discussed. Interactions between hormones that are of potential importance for root growth are described. This creates a framework that can be used for investigating the impact of abiotic stress factors on molecular mechanisms related to plant hormones, with the limited knowledge of the effects of the metals cadmium, copper and zinc on plant hormones and root development included as case example. PMID:26287175

A novel high pressure, high temperature vessel used to conduct long-term stability measurements of silicon MEMS pressure transducers

NASA Astrophysics Data System (ADS)

Wisniewiski, David

2014-03-01

The need to quantify and to improve long-term stability of pressure transducers is a persistent requirement from the aerospace sector. Specifically, the incorporation of real-time pressure monitoring in aircraft landing gear, as exemplified in Tire Pressure Monitoring Systems (TPMS), has placed greater demand on the pressure transducer for improved performance and increased reliability which is manifested in low lifecycle cost and minimal maintenance downtime through fuel savings and increased life of the tire. Piezoresistive (PR) silicon MEMS pressure transducers are the primary choice as a transduction method for this measurement owing to their ability to be designed for the harsh environment seen in aircraft landing gear. However, these pressure transducers are only as valuable as the long-term stability they possess to ensure reliable, real-time monitoring over tens of years. The "heart" of the pressure transducer is the silicon MEMS element, and it is at this basic level where the long-term stability is established and needs to be quantified. A novel High Pressure, High Temperature (HPHT) vessel has been designed and constructed to facilitate this critical measurement of the silicon MEMS element directly through a process of mechanically "floating" the silicon MEMS element while being subjected to the extreme environments of pressure and temperature, simultaneously. Furthermore, the HPHT vessel is scalable to permit up to fifty specimens to be tested at one time to provide a statistically significant data population on which to draw reasonable conclusions on long-term stability. With the knowledge gained on the silicon MEMS element, higher level assembly to the pressure transducer envelope package can also be quantified as to the build-effects contribution to long-term stability in the same HPHT vessel due to its accommodating size. Accordingly, a HPHT vessel offering multiple levels of configurability and robustness in data measurement is presented, along with 10 year long-term stability results.

The Literacy Environment of Early Childhood Special Education Classrooms: Predictors of Print Knowledge

ERIC Educational Resources Information Center

Dynia, Jaclyn M.

2012-01-01

The present study aimed to examine the quality of the classroom literacy environment in early childhood special education (ECSE) classrooms, as well as the relations between the classroom literacy environment and children's gains in print knowledge. To address these aims, the present study described the classroom literacy environments of 28…

Programming Not Required: Skills and Knowledge for the Digital Library Environment

ERIC Educational Resources Information Center

Howard, Katherine

2010-01-01

Education for Library and Information professionals in managing the digital environment has been a key topic for discussion within the LIS environment for some time. However, before designing and implementing a program for digital library education, it is prudent to ensure that the skills and knowledge required to work in this environment are…

Putting more ‘modern’ in modern physics education: a Knowledge Building approach using student questions and ideas about the universe

NASA Astrophysics Data System (ADS)

Wagner, Glenn

2017-03-01

Student-generated questions and ideas about our universe are the start of a rich and highly motivating learning environment. Using their curiosity-driven questions and ideas, students form Knowledge Building groups or ‘communities’ where they plan, set goals, design questions for research, and assess the progress of their work, tasks that were once under the control of the teacher. With the understanding that all knowledge and ideas are treated as improvable, students work collaboratively at their level of competency to share their knowledge, ideas and understandings gained from authoritative sources and laboratory activities. Over time, students work collectively to improve the knowledge and ideas of others that result in advances in understanding that benefit not only the individual but the community as a whole. Learning outcomes reported in this paper demonstrate that a Knowledge Building environment applied to introductory cosmology produced similar gains in knowledge and understanding surrounding foundational concepts compared to teacher-centred learning environments. Aside from new knowledge and understanding, students develop important skills and competencies such as question-asking, idea development, communication, collaboration that are becoming ever more important for 21st century living and working. Finally, the process of planning and initiating a Knowledge Building environment that produced the results reported in this paper is outlined.

Gaining the Long View: Reforming Organization and Empowering Knowledge Workers to Improve Strategy and Intelligence

DTIC Science & Technology

2017-03-31

processes. Hierarchal bureaucracies also provide the workforce with a predictable, structured work environment , a sense of status, and other...processes in response to changes in the environment . As they age and acquire a corporate culture, members become more entrenched in their work ...inability of managers and leaders of knowledge workers to foster a work environment that effectively exploits the knowledge worker’s drive to apply his or

Cell biology symposium: Membrane trafficking and signal transduction

USDA-ARS?s Scientific Manuscript database

In general, membrane trafficking is a broad group of processes where proteins and other large molecules are distributed throughout the cell as well as adjacent extracellular spaces. Whereas signal transduction is a process where signals are transmitted through a series of chemical or molecular event...

Nonparametric Simulation of Signal Transduction Networks with Semi-Synchronized Update

PubMed Central

Nassiri, Isar; Masoudi-Nejad, Ali; Jalili, Mahdi; Moeini, Ali

2012-01-01

Simulating signal transduction in cellular signaling networks provides predictions of network dynamics by quantifying the changes in concentration and activity-level of the individual proteins. Since numerical values of kinetic parameters might be difficult to obtain, it is imperative to develop non-parametric approaches that combine the connectivity of a network with the response of individual proteins to signals which travel through the network. The activity levels of signaling proteins computed through existing non-parametric modeling tools do not show significant correlations with the observed values in experimental results. In this work we developed a non-parametric computational framework to describe the profile of the evolving process and the time course of the proportion of active form of molecules in the signal transduction networks. The model is also capable of incorporating perturbations. The model was validated on four signaling networks showing that it can effectively uncover the activity levels and trends of response during signal transduction process. PMID:22737250

E-cadherin-mediated force transduction signals regulate global cell mechanics

PubMed Central

Muhamed, Ismaeel; Wu, Jun; Sehgal, Poonam; Kong, Xinyu; Tajik, Arash; Wang, Ning

2016-01-01

ABSTRACT This report elucidates an E-cadherin-based force-transduction pathway that triggers changes in cell mechanics through a mechanism requiring epidermal growth factor receptor (EGFR), phosphoinositide 3-kinase (PI3K), and the downstream formation of new integrin adhesions. This mechanism operates in addition to local cytoskeletal remodeling triggered by conformational changes in the E-cadherin-associated protein α-catenin, at sites of mechanical perturbation. Studies using magnetic twisting cytometry (MTC), together with traction force microscopy (TFM) and confocal imaging identified force-activated E-cadherin-specific signals that integrate cadherin force transduction, integrin activation and cell contractility. EGFR is required for the downstream activation of PI3K and myosin-II-dependent cell stiffening. Our findings also demonstrated that α-catenin-dependent cytoskeletal remodeling at perturbed E-cadherin adhesions does not require cell stiffening. These results broaden the repertoire of E-cadherin-based force transduction mechanisms, and define the force-sensitive signaling network underlying the mechano-chemical integration of spatially segregated adhesion receptors. PMID:26966187

Exploring the Impacts of Social Networking Sites on Academic Relations in the University

ERIC Educational Resources Information Center

Rambe, Patient

2011-01-01

Social networking sites (SNS) affordances for persistent interaction, collective generation of knowledge, and formation of peer-based clusters for knowledge sharing render them useful for developing constructivist knowledge environments. However, notwithstanding their academic value, these environments are not necessarily insulated from the…

Knowledge Organization through Multiple Representations in a Computer-Supported Collaborative Learning Environment

ERIC Educational Resources Information Center

Namdar, Bahadir; Shen, Ji

2018-01-01

Computer-supported collaborative learning (CSCL) environments provide learners with multiple representational tools for storing, sharing, and constructing knowledge. However, little is known about how learners organize knowledge through multiple representations about complex socioscientific issues. Therefore, the purpose of this study was to…

Beta-arrestin biased agonism/antagonism at cardiovascular seven transmembrane-spanning receptors.

PubMed

Lymperopoulos, Anastasios

2012-01-01

Heptahelical, G protein-coupled or seven transmembrane-spanning receptors, such as the β-adrenergic and the angiotensin II type 1 receptors, are the most diverse and therapeutically important family of receptors in the human genome, playing major roles in the physiology of various organs/tissues including the heart and blood vessels. Ligand binding activates heterotrimeric G proteins that transmit intracellular signals by regulating effector enzymes or ion channels. G protein signaling is terminated, in large part, by phosphorylation of the agonist-bound receptor by the G-protein coupled receptor kinases (GRKs), followed by βarrestin binding, which uncouples the phosphorylated receptor from the G protein and subsequently targets the receptor for internalization. As the receptor-βarrestin complex enters the cell, βarrestin-1 and -2, the two mammalian βarrestin isoforms, serve as ligand-regulated scaffolds that recruit a host of intracellular proteins and signal transducers, thus promoting their own wave of signal transduction independently of G-proteins. A constantly increasing number of studies over the past several years have begun to uncover specific roles played by these ubiquitously expressed receptor adapter proteins in signal transduction of several important heptahelical receptors regulating the physiology of various organs/ systems, including the cardiovascular (CV) system. Thus, βarrestin-dependent signaling has increasingly been implicated in CV physiology and pathology, presenting several exciting opportunities for therapeutic intervention in the treatment of CV disorders. Additionally, the discovery of this novel mode of heptahelical receptor signaling via βarrestins has prompted a revision of classical pharmacological concepts such as receptor agonism/antagonism, as well as introduction of new terms such as "biased signaling", which refers to ligand-specific activation of selective signal transduction pathways by the very same receptor. The present review gives an overview of the current knowledge in the field of βarrestin-dependent signaling, with a specific focus on CV heptahelical receptor βarrestin-mediated signaling and on "biased" CV heptahelical receptor ligands that promote or inhibit it. Exciting new possibilities for cardiovascular therapeutics arising from the delineation of this βarrestin-dependent signaling are also discussed.

Chemistry and biology of the initial steps in vision: the Friedenwald lecture.

PubMed

Palczewski, Krzysztof

2014-10-22

Visual transduction is the process in the eye whereby absorption of light in the retina is translated into electrical signals that ultimately reach the brain. The first challenge presented by visual transduction is to understand its molecular basis. We know that maintenance of vision is a continuous process requiring the activation and subsequent restoration of a vitamin A-derived chromophore through a series of chemical reactions catalyzed by enzymes in the retina and retinal pigment epithelium (RPE). Diverse biochemical approaches that identified key proteins and reactions were essential to achieve a mechanistic understanding of these visual processes. The three-dimensional arrangements of these enzymes' polypeptide chains provide invaluable insights into their mechanisms of action. A wealth of information has already been obtained by solving high-resolution crystal structures of both rhodopsin and the retinoid isomerase from pigment RPE (RPE65). Rhodopsin, which is activated by photoisomerization of its 11-cis-retinylidene chromophore, is a prototypical member of a large family of membrane-bound proteins called G protein-coupled receptors (GPCRs). RPE65 is a retinoid isomerase critical for regeneration of the chromophore. Electron microscopy (EM) and atomic force microscopy have provided insights into how certain proteins are assembled to form much larger structures such as rod photoreceptor cell outer segment membranes. A second challenge of visual transduction is to use this knowledge to devise therapeutic approaches that can prevent or reverse conditions leading to blindness. Imaging modalities like optical coherence tomography (OCT) and scanning laser ophthalmoscopy (SLO) applied to appropriate animal models as well as human retinal imaging have been employed to characterize blinding diseases, monitor their progression, and evaluate the success of therapeutic agents. Lately two-photon (2-PO) imaging, together with biochemical assays, are revealing functional aspects of vision at a new molecular level. These multidisciplinary approaches combined with suitable animal models and inbred mutant species can be especially helpful in translating provocative cell and tissue culture findings into therapeutic options for further development in animals and eventually in humans. A host of different approaches and techniques is required for substantial progress in understanding fundamental properties of the visual system. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

The Paradox of Oestradiol-Induced Breast Cancer Cell Growth and Apoptosis.

PubMed

Maximov, Philipp Y; Lewis-Wambi, Joan S; Jordan, V Craig

2009-05-01

High dose oestrogen therapy was used as a treatment for postmenopausal patients with breast cancer from the 1950s until the introduction of the safer antioestrogen, tamoxifen in the 1970s. The anti-tumour mechanism of high dose oestrogen therapy remained unknown. There was no enthusiasm to study these signal transduction pathways as oestrogen therapy has almost completely been eliminated from the treatment paradigm. Current use of tamoxifen and the aromatase inhibitors seek to create oestrogen deprivation that prevents the growth of oestrogen stimulated oestrogen receptor (ER) positive breast cancer cells. However, acquired resistance to antihormonal therapy does occur, but it is through investigation of laboratory models that a vulnerability of the cancer cell has been discovered and is being investigated to provide new opportunities in therapy with the potential for discovering new cancer-specific apoptotic drugs. Laboratory models of resistance to raloxifene and tamoxifen, the selective oestrogen receptor modulators (SERMs) and aromatase inhibitors demonstrate an evolution of drug resistance so that after many years of oestrogen deprivation, the ER positive cancer cell reconfigures the survival signal transduction pathways so oestrogen now becomes an apoptotic trigger rather than a survival signal. Current efforts are evaluating the mechanisms of oestrogen-induced apoptosis and how this new biology of oestrogen action can be amplified and enhanced, thereby increasing the value of this therapeutic opportunity for the treatment of breast cancer. Several synergistic approaches to therapeutic enhancement are being advanced which involve drug combinations to impair survival signaling with the use of specific agents and to impair bcl-2 that protects the cancer cell from apoptosis. We highlight the historical understanding of oestrogen's role in cell survival and death and specifically illustrate the progress that has been made in the last five years to understand the mechanisms of oestrogen-induced apoptosis. There are opportunities to harness knowledge from this new signal transduction pathway to discover the precise mechanism of this oestrogen-induced apoptotic trigger. Indeed, the new biology of oestrogen action also has significance for understanding the physiology of bone remodeling. Thus, the pathway has a broad appeal in both physiology and cancer research.

Improving the Transduction of Bone Marrow–Derived Cells with an Integrase-Defective Lentiviral Vector

PubMed Central

Pay, S. Louise; Qi, Xiaoping; Willard, Jeffrey F.; Godoy, Juliana; Sankhavaram, Kavya; Horton, Ranier; Mitter, Sayak K.; Quigley, Judith L.; Chang, Lung-Ji; Grant, Maria B.; Boulton, Michael E.

2018-01-01

In lentiviral vector (LV) applications where transient transgene expression is sufficient, integrase-defective lentiviral vectors (IDLVs) are beneficial for reducing the potential for off-target effects associated with insertional mutagenesis. It was previously demonstrated that human RPE65 mRNA expression from an integrating lentiviral vector (ILV) induces endogenous Rpe65 and Cralbp mRNA expression in murine bone marrow–derived cells (BMDCs), initiating programming of the cells to retinal pigment epithelium (RPE)-like cells. These cells regenerate RPE in retinal degeneration models when injected systemically. As transient expression of RPE65 is sufficient to activate endogenous RPE-associated genes for programming BMDCs, use of an ILV is an unnecessary risk. In this study, an IDLV expressing RPE65 (IDLV3-RPE65) was generated. Transduction with IDLV3-RPE65 is less efficient than the integrating vector (ILV3-RPE65). Therefore, IDLV3-RPE65 transduction was enhanced with a combination of preloading 20 × -concentrated viral supernatant on RetroNectin at a multiplicity of infection of 50 and transduction of BMDCs by low-speed centrifugation. RPE65 mRNA levels increased from ∼12-fold to ∼25-fold (p < 0.05) after modification of the IDLV3-RPE65 transduction protocol, achieving expression similar to the ∼27-fold (p < 0.05) increase observed with ILV3-RPE65. Additionally, the study shows that the same preparation of RetroNectin can be used to coat up to three wells with no reduction in transduction. Critically, IDLV3-RPE65 transduction initiates endogenous Rpe65 mRNA expression in murine BMDCs and Cralbp/CRALBP mRNA in both murine and human BMDCs, similar to expression observed in ILV3-RPE65-transduced cells. Systemic administration of ILV3-RPE65 or IDLV3-RPE65 programmed BMDCs in a mouse model of retinal degeneration is sufficient to retain visual function and reduce retinal degeneration compared to mice receiving no treatment or naïve BMDC. It is concluded that IDLV3-RPE65 is appropriate for programming BMDCs to RPE-like cells. PMID:29160102

The Knowledge-Integrated Network Biomarkers Discovery for Major Adverse Cardiac Events

PubMed Central

Jin, Guangxu; Zhou, Xiaobo; Wang, Honghui; Zhao, Hong; Cui, Kemi; Zhang, Xiang-Sun; Chen, Luonan; Hazen, Stanley L.; Li, King; Wong, Stephen T. C.

2010-01-01

The mass spectrometry (MS) technology in clinical proteomics is very promising for discovery of new biomarkers for diseases management. To overcome the obstacles of data noises in MS analysis, we proposed a new approach of knowledge-integrated biomarker discovery using data from Major Adverse Cardiac Events (MACE) patients. We first built up a cardiovascular-related network based on protein information coming from protein annotations in Uniprot, protein–protein interaction (PPI), and signal transduction database. Distinct from the previous machine learning methods in MS data processing, we then used statistical methods to discover biomarkers in cardiovascular-related network. Through the tradeoff between known protein information and data noises in mass spectrometry data, we finally could firmly identify those high-confident biomarkers. Most importantly, aided by protein–protein interaction network, that is, cardiovascular-related network, we proposed a new type of biomarkers, that is, network biomarkers, composed of a set of proteins and the interactions among them. The candidate network biomarkers can classify the two groups of patients more accurately than current single ones without consideration of biological molecular interaction. PMID:18665624

Perception of the plant hormone ethylene: known-knowns and known-unknowns.

PubMed

Light, Kenneth M; Wisniewski, John A; Vinyard, W Andrew; Kieber-Emmons, Matthew T

2016-09-01

The gaseous phytohormone ethylene is implicated in virtually all phases of plant growth and development and thus has a major impact on crop production. This agronomic impact makes understanding ethylene signaling the Philosopher's Stone of the plant biotechnology world in applications including post-harvest transport of foodstuffs, consistency of foodstuff maturity pre-harvest, decorative flower freshness and longevity, and biomass production for biofuel applications. Ethylene is biosynthesized by plants in response to environmental factors and plant life-cycle events, and triggers a signaling cascade that modulates over 1000 genes. The key components in the perception of ethylene are a family of copper dependent receptors, the bioinorganic chemistry of which has been largely ignored by the chemical community. Since identification of these receptors two decades ago, there has been tremendous growth in knowledge in the biological community on the signal transduction pathways and mechanisms of ethylene signaling. In this review, we highlight these advances and key chemical voids in knowledge that are overdue for exploration, and which are required to ultimately regulate and control ethylene signaling.

Nitrogen Assimilation in Escherichia coli: Putting Molecular Data into a Systems Perspective

PubMed Central

van Heeswijk, Wally C.; Westerhoff, Hans V.

2013-01-01

SUMMARY We present a comprehensive overview of the hierarchical network of intracellular processes revolving around central nitrogen metabolism in Escherichia coli. The hierarchy intertwines transport, metabolism, signaling leading to posttranslational modification, and transcription. The protein components of the network include an ammonium transporter (AmtB), a glutamine transporter (GlnHPQ), two ammonium assimilation pathways (glutamine synthetase [GS]-glutamate synthase [glutamine 2-oxoglutarate amidotransferase {GOGAT}] and glutamate dehydrogenase [GDH]), the two bifunctional enzymes adenylyl transferase/adenylyl-removing enzyme (ATase) and uridylyl transferase/uridylyl-removing enzyme (UTase), the two trimeric signal transduction proteins (GlnB and GlnK), the two-component regulatory system composed of the histidine protein kinase nitrogen regulator II (NRII) and the response nitrogen regulator I (NRI), three global transcriptional regulators called nitrogen assimilation control (Nac) protein, leucine-responsive regulatory protein (Lrp), and cyclic AMP (cAMP) receptor protein (Crp), the glutaminases, and the nitrogen-phosphotransferase system. First, the structural and molecular knowledge on these proteins is reviewed. Thereafter, the activities of the components as they engage together in transport, metabolism, signal transduction, and transcription and their regulation are discussed. Next, old and new molecular data and physiological data are put into a common perspective on integral cellular functioning, especially with the aim of resolving counterintuitive or paradoxical processes featured in nitrogen assimilation. Finally, we articulate what still remains to be discovered and what general lessons can be learned from the vast amounts of data that are available now. PMID:24296575

Systematic mapping of two component response regulators to gene targets in a model sulfate reducing bacterium.

PubMed

Rajeev, Lara; Luning, Eric G; Dehal, Paramvir S; Price, Morgan N; Arkin, Adam P; Mukhopadhyay, Aindrila

2011-10-12

Two component regulatory systems are the primary form of signal transduction in bacteria. Although genomic binding sites have been determined for several eukaryotic and bacterial transcription factors, comprehensive identification of gene targets of two component response regulators remains challenging due to the lack of knowledge of the signals required for their activation. We focused our study on Desulfovibrio vulgaris Hildenborough, a sulfate reducing bacterium that encodes unusually diverse and largely uncharacterized two component signal transduction systems. We report the first systematic mapping of the genes regulated by all transcriptionally acting response regulators in a single bacterium. Our results enabled functional predictions for several response regulators and include key processes of carbon, nitrogen and energy metabolism, cell motility and biofilm formation, and responses to stresses such as nitrite, low potassium and phosphate starvation. Our study also led to the prediction of new genes and regulatory networks, which found corroboration in a compendium of transcriptome data available for D. vulgaris. For several regulators we predicted and experimentally verified the binding site motifs, most of which were discovered as part of this study. The gene targets identified for the response regulators allowed strong functional predictions to be made for the corresponding two component systems. By tracking the D. vulgaris regulators and their motifs outside the Desulfovibrio spp. we provide testable hypotheses regarding the functions of orthologous regulators in other organisms. The in vitro array based method optimized here is generally applicable for the study of such systems in all organisms.

Circulating Tumor Cells: What Is in It for the Patient? A Vision towards the Future

PubMed Central

van de Stolpe, Anja; den Toonder, Jaap M. J.

2014-01-01

Knowledge on cellular signal transduction pathways as drivers of cancer growth and metastasis has fuelled development of “targeted therapy” which “targets” aberrant oncogenic signal transduction pathways. These drugs require nearly invariably companion diagnostic tests to identify the tumor-driving pathway and the cause of the abnormal pathway activity in a tumor sample, both for therapy response prediction as well as for monitoring of therapy response and emerging secondary drug resistance. Obtaining sufficient tumor material for this analysis in the metastatic setting is a challenge, and circulating tumor cells (CTCs) may provide an attractive alternative to biopsy on the premise that they can be captured from blood and the companion diagnostic test results are correctly interpreted. We discuss novel companion diagnostic directions, including the challenges, to identify the tumor driving pathway in CTCs, which in combination with a digital pathology platform and algorithms to quantitatively interpret complex CTC diagnostic results may enable optimized therapy response prediction and monitoring. In contrast to CTC-based companion diagnostics, CTC enumeration is envisioned to be largely replaced by cell free tumor DNA measurements in blood for therapy response and recurrence monitoring. The recent emergence of novel in vitro human model systems in the form of cancer-on-a-chip may enable elucidation of some of the so far elusive characteristics of CTCs, and is expected to contribute to more efficient CTC capture and CTC-based diagnostics. PMID:24879438

Metabotropic Glutamate Receptors and Interacting Proteins in Epileptogenesis

PubMed Central

Qian, Feng; Tang, Feng-Ru

2016-01-01

Neurotransmitter and receptor systems are involved in different neurological and neuropsychological disorders such as Parkinson's disease, depression, Alzheimer’s disease and epilepsy. Recent advances in studies of signal transduction pathways or interacting proteins of neurotransmitter receptor systems suggest that different receptor systems may share the common signal transduction pathways or interacting proteins which may be better therapeutic targets for development of drugs to effectively control brain diseases. In this paper, we reviewed metabotropic glutamate receptors (mGluRs) and their related signal transduction pathways or interacting proteins in status epilepticus and temporal lobe epilepsy, and proposed some novel therapeutical drug targets for controlling epilepsy and epileptogenesis. PMID:27030135

The role of viscous fluid flow in cochlear partition transduction

NASA Astrophysics Data System (ADS)

Svobodny, Thomas

2002-11-01

Sound transduction occurs via the forcing of the basilar membrane by a wave set up in the cochlear chamber. At the threshold of hearing the amplitude of the vibrations is on the nanometer scale. Fluid flow in this chamber is at very low Reynolds number. The actual transduction occurs through the mechanism of stereocilia of hair cells. We will describe the three-dimensional distribution of energy and how fluid flow affects stereociliar deflection due to the influence of the dynamics of the endothelial fluid. This talk will emphasis the results of two-dimensional and three-dimensional simulations and will relate these to the analytical solutions previously reported.

Examining Collaborative Knowledge Construction in Microblogging-Based Learning Environments

ERIC Educational Resources Information Center

Luo, Tian; Clifton, Lacey

2017-01-01

Aim/Purpose: The purpose of the study is to provide foundational research to exemplify how knowledge construction takes place in microblogging-based learning environments, to understand learner interaction representing the knowledge construction process, and to analyze learner perception, thereby suggesting a model of delivery for microblogging.…

Sleep Enhances Knowledge of Routes and Regions in Spatial Environments

ERIC Educational Resources Information Center

Noack, Hannes; Schick, Wiebke; Mallot, Hanspeter; Born, Jan

2017-01-01

Sleep is thought to preferentially consolidate hippocampus-dependent memory, and as such, spatial navigation. Here, we investigated the effects of sleep on route knowledge and explicit and implicit semantic regions in a virtual environment. Sleep, compared with wakefulness, improved route knowledge and also enhanced awareness of the semantic…

Learning Ecosystem Complexity: A Study on Small-Scale Fishers' Ecological Knowledge Generation

ERIC Educational Resources Information Center

Garavito-Bermúdez, Diana

2018-01-01

Small-scale fisheries are learning contexts of importance for generating, transferring and updating ecological knowledge of natural environments through everyday work practices. The rich knowledge fishers have of local ecosystems is the result of the intimate relationship fishing communities have had with their natural environments across…

PERKAM: Personalized Knowledge Awareness Map for Computer Supported Ubiquitous Learning

ERIC Educational Resources Information Center

El-Bishouty, Moushir M.; Ogata, Hiroaki; Yano, Yoneo

2007-01-01

This paper introduces a ubiquitous computing environment in order to support the learners while doing tasks; this environment is called PERKAM (PERsonalized Knowledge Awareness Map). PERKAM allows the learners to share knowledge, interact, collaborate, and exchange individual experiences. It utilizes the RFID ubiquities technology to detect the…

Syngeneic AAV pseudo-vectors potentiates full vector transduction

USDA-ARS?s Scientific Manuscript database

An excessive amount of empty capsids are generated during regular AAV vector production process. These pseudo-vectors often remain in final vectors used for animal studies or clinical trials. The potential effects of these pseudo-vectors on AAV transduction have been a major concern. In the current ...

Controlled release of GAG-binding enhanced transduction (GET) peptides for sustained and highly efficient intracellular delivery.

PubMed

Abu-Awwad, Hosam Al-Deen M; Thiagarajan, Lalitha; Dixon, James E

2017-07-15

Controlled release systems for therapeutic molecules are vital to allow the sustained local delivery of their activities which direct cell behaviour and enable novel regenerative strategies. Direct programming of cells using exogenously delivered transcription factors can by-pass growth factor signalling but there is still a requirement to deliver such activity spatio-temporally. We previously developed a technology termed GAG-binding enhanced transduction (GET) to efficiently deliver a variety of cargoes intracellularly, using GAG-binding domains which promote cell targeting, and cell penetrating peptides (CPPs) which allow cell entry. Herein we demonstrate that GET system can be used in controlled release systems to mediate sustained intracellular transduction over one week. We assessed the stability and activity of GET peptides in poly(dl-lactic acid-co-glycolic acid) (PLGA) microparticles (MPs) prepared using a S/O/W double emulsion method. Efficient encapsulation (∼65%) and tailored protein release profiles could be achieved, however intracellular transduction was significantly inhibited post-release. To retain GET peptide activity we optimized a strategy of co-encapsulation of l-Histidine, which may form a complex with the PLGA degradation products under acidic conditions. Simulations of the polymer microclimate showed that hydrolytic acidic PLGA degradation products directly inhibited GET peptide transduction activity, and use of l-Histidine significantly enhanced released protein delivery. The ability to control the intracellular transduction of functional proteins into cells will facilitate new localized delivery methods and allow approaches to direct cellular behaviour for many regenerative medicine applications. The goal for regenerative medicine is to restore functional biological tissue by controlling and augmenting cellular behaviour. Either Transcription (TFs) or growth factors (GFs) can be presented to cells in spatio-temporal gradients for programming cell fate and gene expression. Here, we have created a sustained and controlled release system for GET (Glycosaminoglycan-enhanced transducing)-tagged proteins using S/O/W PLGA microparticle fabrication. We demonstrated that PLGA and its acidic degradants inhibit GET-mediated transduction, which can be overcome by using pH-activated l-Histidine. l-Histidine inhibits the electrostatic interaction of GET/PLGA and allows enhanced intracellular transduction. GET could provide a powerful tool to program cell behaviour either in gradients or with sustained delivery. We believe that our controlled release systems will allow application of GET for tissue regeneration directly by TF cellular programming. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Olfactory transduction pathways in the Senegalese sole Solea senegalensis.

PubMed

Velez, Z; Hubbard, P C; Barata, E N; Canário, A V M

2013-09-01

This study tested whether differences in sensitivity between the upper and lower olfactory epithelia of Solea senegalensis are associated with different odorant receptors and transduction pathways, using the electro-olfactogram. Receptor mechanisms were assessed by cross-adaptation with amino acids (L-cysteine, L-phenylalanine and 1-methyl-L-tryptophan) and bile acids (taurocholic acid and cholic acid). This suggested that relatively specific receptors exist for 1-methyl-L-tryptophan and L-phenylalanine (food-related odorants) in the lower epithelium, and for taurocholic acid (conspecific-derived odorant) in the upper. Inhibition by U73122 [a phospholipase C (PLC) inhibitor] suggested that olfactory responses to amino acids were mediated mostly, but not entirely, by PLC-mediated transduction (IC50 ; 15-55 nM), whereas bile acid responses were mediated by both PLC and adenylate cyclase-cyclic adenosine monophosphate (AC-cAMP) (using SQ-22536; an AC inhibitor). Simultaneous application of both drugs rarely inhibited responses completely, suggesting possible involvement of non-PLC and non-AC mediated mechanisms. For aromatic amino acids and bile acids, there were differences in the contribution of each transduction pathway (PLC, AC and non-PLC and non-AC) between the two epithelia. These results suggest that differences in sensitivity of the two epithelia are associated with differences in odorant receptors and transduction mechanisms. © 2013 The Fisheries Society of the British Isles.

[Effect of mitogen activated protein kinase signal transduction on apoptosis of PC12 cells induced by electromagnetic exposure].

PubMed

Yang, Xue-Sen; Zhang, Wei; Gong, Qian-Fen

2008-06-01

To observe the effect of mitogen activated protein kinase (MAPK) signal transduction system on the apoptosis induced by electromagnetic exposure in PC12 cells. After pretreated by SB203580 alone or together with U0126, PC12 cells were exposed to 65 mW/cm(2) electromagnetic wave for 20 min. The phosphorylations of ERK1/2, JNK and P38 MAPK were tested by Western-blot at 3 h and 24 h after electromagnetic exposure. The apoptosis of PC12 cells were detected by Annexin-V-FITC flow cytometry. U0126, but not SB203580 could inhibit the activation of ERK1/2 induced by electromagnetic exposure. U0126 and SB203580 had no effects on the activation of JNK. SB203580 could inhibit the activation of P38 MAPK significantly. But U0126 had no such effect on the activation of P38 MAPK. After pretreated by SB203580 alone or together with U0126, the apoptosis of PC12 cells decreased. But the pretreatment by U0126 alone had no influence on the apoptosis of PC12 cells. The P38 MAPK signal transduction modulate the apoptosis of PC12 cells induced by electromagnetic exposure. ERK signal transduction has no effect on the apoptosis of PC12 cells. JNK signal transduction may promote the apoptosis of PC12 cells in the early stage after electromagnetic exposure.

Integration of adeno-associated virus vectors in CD34+ human hematopoietic progenitor cells after transduction.

PubMed

Fisher-Adams, G; Wong, K K; Podsakoff, G; Forman, S J; Chatterjee, S

1996-07-15

Gene transfer vectors based on adeno-associated virus (AAV) appear promising because of their high transduction frequencies regardless of cell cycle status and ability to integrate into chromosomal DNA. We tested AAV-mediated gene transfer into a panel of human bone marrow or umbilical cord-derived CD34+ hematopoietic progenitor cells, using vectors encoding several transgenes under the control of viral and cellular promoters. Gene transfer was evaluated by (1) chromosomal integration of vector sequences and (2) analysis of transgene expression. Southern hybridization and fluorescence in situ hybridization analysis of transduced CD34 genomic DNA showed the presence of integrated vector sequences in chromosomal DNA in a portion of transduced cells and showed that integrated vector sequences were replicated along with cellular DNA during mitosis. Transgene expression in transduced CD34 cells in suspension cultures and in myeloid colonies differentiating in vitro from transduced CD34 cells approximated that predicted by the multiplicity of transduction. This was true in CD34 cells from different donors, regardless of the transgene or selective pressure. Comparisons of CD34 cell transduction either before or after cytokine stimulation showed similar gene transfer frequencies. Our findings suggest that AAV transduction of CD34+ hematopoietic progenitor cells is efficient, can lead to stable integration in a population of transduced cells, and may therefore provide the basis for safe and efficient ex vivo gene therapy of the hematopoietic system.

Characterization of adenoviral transduction profile in prostate cancer cells and normal prostate tissue.

PubMed

Ai, Jianzhong; Tai, Phillip W L; Lu, Yi; Li, Jia; Ma, Hong; Su, Qin; Wei, Qiang; Li, Hong; Gao, Guangping

2017-09-01

Prostate diseases are common in males worldwide with high morbidity. Gene therapy is an attractive therapeutic strategy for prostate diseases, however, it is currently underdeveloped. As well known, adeno virus (Ad) is the most widely used gene therapy vector. The aims of this study are to explore transduction efficiency of Ad in prostate cancer cells and normal prostate tissue, thus further providing guidance for future prostate pathophysiological studies and therapeutic development of prostate diseases. We produced Ad expressing enhanced green fluorescence protein (EGFP), and characterized the transduction efficiency of Ad in both human and mouse prostate cancer cell lines in vitro, as well as prostate tumor xenograft, and wild-type mouse prostate tissue in vivo. Ad transduction efficiency was determined by EGFP fluorescence using microscopy and flow cytometry. Cell type-specific transduction was examined by immunofluorescence staining of cell markers. Our data showed that Ad efficiently transduced human and mouse prostate cancer cells in vitro in a dose dependent manner. Following intratumoral and intraprostate injection, Ad could efficiently transduce prostate tumor xenograft and the major prostatic cell types in vivo, respectively. Our findings suggest that Ad can efficiently transduce prostate tumor cells in vitro as well as xenograft and normal prostate tissue in vivo, and further indicate that Ad could be a potentially powerful toolbox for future gene therapy of prostate diseases. © 2017 Wiley Periodicals, Inc.

Multi-model-based interactive authoring environment for creating shareable medical knowledge.

PubMed

Ali, Taqdir; Hussain, Maqbool; Ali Khan, Wajahat; Afzal, Muhammad; Hussain, Jamil; Ali, Rahman; Hassan, Waseem; Jamshed, Arif; Kang, Byeong Ho; Lee, Sungyoung

2017-10-01

Technologically integrated healthcare environments can be realized if physicians are encouraged to use smart systems for the creation and sharing of knowledge used in clinical decision support systems (CDSS). While CDSSs are heading toward smart environments, they lack support for abstraction of technology-oriented knowledge from physicians. Therefore, abstraction in the form of a user-friendly and flexible authoring environment is required in order for physicians to create shareable and interoperable knowledge for CDSS workflows. Our proposed system provides a user-friendly authoring environment to create Arden Syntax MLM (Medical Logic Module) as shareable knowledge rules for intelligent decision-making by CDSS. Existing systems are not physician friendly and lack interoperability and shareability of knowledge. In this paper, we proposed Intelligent-Knowledge Authoring Tool (I-KAT), a knowledge authoring environment that overcomes the above mentioned limitations. Shareability is achieved by creating a knowledge base from MLMs using Arden Syntax. Interoperability is enhanced using standard data models and terminologies. However, creation of shareable and interoperable knowledge using Arden Syntax without abstraction increases complexity, which ultimately makes it difficult for physicians to use the authoring environment. Therefore, physician friendliness is provided by abstraction at the application layer to reduce complexity. This abstraction is regulated by mappings created between legacy system concepts, which are modeled as domain clinical model (DCM) and decision support standards such as virtual medical record (vMR) and Systematized Nomenclature of Medicine - Clinical Terms (SNOMED CT). We represent these mappings with a semantic reconciliation model (SRM). The objective of the study is the creation of shareable and interoperable knowledge using a user-friendly and flexible I-KAT. Therefore we evaluated our system using completeness and user satisfaction criteria, which we assessed through the system- and user-centric evaluation processes. For system-centric evaluation, we compared the implementation of clinical information modelling system requirements in our proposed system and in existing systems. The results suggested that 82.05% of the requirements were fully supported, 7.69% were partially supported, and 10.25% were not supported by our system. In the existing systems, 35.89% of requirements were fully supported, 28.20% were partially supported, and 35.89% were not supported. For user-centric evaluation, the assessment criterion was 'ease of use'. Our proposed system showed 15 times better results with respect to MLM creation time than the existing systems. Moreover, on average, the participants made only one error in MLM creation using our proposed system, but 13 errors per MLM using the existing systems. We provide a user-friendly authoring environment for creation of shareable and interoperable knowledge for CDSS to overcome knowledge acquisition complexity. The authoring environment uses state-of-the-art decision support-related clinical standards with increased ease of use. Copyright © 2017 Elsevier B.V. All rights reserved.

Virtual reality training improves students' knowledge structures of medical concepts.

PubMed

Stevens, Susan M; Goldsmith, Timothy E; Summers, Kenneth L; Sherstyuk, Andrei; Kihmm, Kathleen; Holten, James R; Davis, Christopher; Speitel, Daniel; Maris, Christina; Stewart, Randall; Wilks, David; Saland, Linda; Wax, Diane; Panaiotis; Saiki, Stanley; Alverson, Dale; Caudell, Thomas P

2005-01-01

Virtual environments can provide training that is difficult to achieve under normal circumstances. Medical students can work on high-risk cases in a realistic, time-critical environment, where students practice skills in a cognitively demanding and emotionally compelling situation. Research from cognitive science has shown that as students acquire domain expertise, their semantic organization of core domain concepts become more similar to those of an expert's. In the current study, we hypothesized that students' knowledge structures would become more expert-like as a result of their diagnosing and treating a patient experiencing a hematoma within a virtual environment. Forty-eight medical students diagnosed and treated a hematoma case within a fully immersed virtual environment. Student's semantic organization of 25 case-related concepts was assessed prior to and after training. Students' knowledge structures became more integrated and similar to an expert knowledge structure of the concepts as a result of the learning experience. The methods used here for eliciting, representing, and evaluating knowledge structures offer a sensitive and objective means for evaluating student learning in virtual environments and medical simulations.

METHODS FOR STUDYING BACTERIAL GENE TRANSFER IN SOIL BY CONJUGATION AND TRANSDUCTION

EPA Science Inventory

The purpose of this document is to provide a series of protocols by which a trained technician can conduct studies on the transfer of genetic information by conjugation or transduction in soil, with emphasis on bacteria containing recombinant DNA. The level of the document is gea...

EVA: Collaborative Distributed Learning Environment Based in Agents.

ERIC Educational Resources Information Center

Sheremetov, Leonid; Tellez, Rolando Quintero

In this paper, a Web-based learning environment developed within the project called Virtual Learning Spaces (EVA, in Spanish) is presented. The environment is composed of knowledge, collaboration, consulting, experimentation, and personal spaces as a collection of agents and conventional software components working over the knowledge domains. All…

EVA: An Interactive Web-Based Collaborative Learning Environment

ERIC Educational Resources Information Center

Sheremetov, Leonid; Arenas, Adolfo Guzman

2002-01-01

In this paper, a Web-based learning environment developed within the project called Virtual Learning Spaces (EVA, in Spanish) is described. The environment is composed of knowledge, collaboration, consulting and experimentation spaces as a collection of agents and conventional software components working over the knowledge domains. All user…

Identification of the amino acids essential for LytSR-mediated signal transduction in Staphylococcus aureus and their roles in biofilm-specific gene expression

PubMed Central

Lehman, McKenzie K.; Bose, Jeffrey L.; Sharma-Kuinkel, Batu K.; Moormeier, Derek E.; Endres, Jennifer L.; Sadykov, Marat R.; Biswas, Indranil; Bayles, Kenneth W.

2015-01-01

Summary Recent studies have demonstrated that expression of the Staphylococcus aureus lrgAB operon is specifically expressed within tower structures during biofilm development. To gain a better understanding of the mechanisms underlying this spatial control of lrgAB expression, we carried out a detailed analysis of the LytSR two-component system. Specifically, a conserved aspartic acid (Asp53) of the LytR response regulator was shown to be the target of phosphorylation, which resulted in enhanced binding to the lrgAB promoter and activation of transcription. In addition, we identified His390 of the LytS histidine kinase as the site of autophosphorylation and Asn394 as a critical amino acid involved in phosphatase activity. Interestingly, LytS-independent activation of LytR was observed during planktonic growth, with acetyl phosphate acting as a phosphodonor to LytR. In contrast, mutations disrupting the function of LytS prevented tower-specific lrgAB expression, providing insight into the physiologic environment within these structures. In addition, over activation of LytR led to increased lrgAB promoter activity during planktonic and biofilm growth and a change in biofilm morphology. Overall, the results of this study are the first to define the LytSR signal transduction pathway, as well as determine the metabolic context within biofilm tower structures that triggers these signaling events. PMID:25491472

Toxic responses of Perna viridis hepatopancreas exposed to DDT, benzo(a)pyrene and their mixture uncovered by iTRAQ-based proteomics and NMR-based metabolomics.

PubMed

Song, Qinqin; Zhou, Hailong; Han, Qian; Diao, Xiaoping

2017-11-01

Dichlorodiphenyltrichloroethane (DDT) and benzo(a)pyrene (BaP) are environmental estrogens (EEs) that are ubiquitous in the marine environment. In the present study, we integrated isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic and nuclear magnetic resonance (NMR)-based metabolomic approaches to explore the toxic responses of green mussel hepatopancreas exposed to DDT (10μg/L), BaP (10μg/L) and their mixture. The metabolic responses indicated that BaP primarily disturbed energy metabolism and osmotic regulation in the hepatopancreas of the male green mussel P. viridis. Both DDT and the mixture of DDT and BaP perturbed the energy metabolism and osmotic regulation in P. viridis. The proteomic responses revealed that BaP affected the proteins involved in energy metabolism, material transformation, cytoskeleton, stress responses, reproduction and development in green mussels. DDT exposure could change the proteins involved in primary metabolism, stress responses, cytoskeleton and signal transduction. However, the mixture of DDT and BaP altered proteins associated with material and energy metabolism, stress responses, signal transduction, reproduction and development, cytoskeleton and apoptosis. This study showed that iTRAQ-based proteomic and NMR-based metabolomic approaches could effectively elucidate the essential molecular mechanism of disturbances in hepatopancreas function of green mussels exposed to environmental estrogens. Copyright © 2017 Elsevier B.V. All rights reserved.

Lipopolysaccharides elicit an oxidative burst as a component of the innate immune system in the seagrass Thalassia testudinum.

PubMed

Loucks, Kyle; Waddell, David; Ross, Cliff

2013-09-01

This study represents the first report characterizing the biological effects of a lipopolysaccharide (LPS) immune modulator on a marine vascular plant. LPS was shown to serve as a strong elicitor of the early defense response in the subtropical seagrass Thalassia testudinum Banks ex König and was capable of inducing an oxidative burst identified at the single cell level. The formation of reactive oxygen species (ROS), detected by a redox-sensitive fluorescent probe and luminol-based chemiluminescence, included a diphenyleneiodonium sensitive response, suggesting the involvement of an NADPH oxidase. A 900 bp cDNA fragment coding for this enzyme was sequenced and found to encode a NAD binding pocket domain with extensive homology to the Arabidopsis thaliana rbohF (respiratory burst oxidase homolog) gene. The triggered release of ROS occurred at 20 min post-elicitation and was dose-dependent, requiring a minimal threshold of 50 μg/mL LPS. Pharmacological dissection of the early events preceding ROS emission indicated that the signal transduction chain of events involved extracellular alkalinization, G-proteins, phospholipase A2, as well as K(+), Ca(2+), and anion channels. Despite exclusively thriving in a marine environment, seagrasses contain ROS-generating machinery and signal transduction components that appear to be evolutionarily conserved with the well-characterized defense response systems found in terrestrial plants. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Comparative proteomic analyses reveal the proteome response to short-term drought in Italian ryegrass (Lolium multiflorum)

PubMed Central

Wang, Jianping; Wang, Pengxi; Ma, Xiao; Zhou, Meiliang; Li, Ji; Gang, Nie; Feng, Guangyan; Zhao, Junming

2017-01-01

Drought is a major abiotic stress that impairs growth and productivity of Italian ryegrass. Comparative analysis of drought responsive proteins will provide insight into molecular mechanism in Lolium multiflorum drought tolerance. Using the iTRAQ-based approach, proteomic changes in tolerant and susceptible lines were examined in response to drought condition. A total of 950 differentially accumulated proteins was found to be involved in carbohydrate metabolism, amino acid metabolism, biosynthesis of secondary metabolites, and signal transduction pathway, such as β-D-xylosidase, β-D-glucan glucohydrolase, glycerate dehydrogenase, Cobalamin-independent methionine synthase, glutamine synthetase 1a, Farnesyl pyrophosphate synthase, diacylglycerol, and inositol 1, 4, 5-trisphosphate, which might contributed to enhance drought tolerance or adaption in Lolium multiflorum. Interestingly, the two specific metabolic pathways, arachidonic acid and inositol phosphate metabolism including differentially accumulated proteins, were observed only in the tolerant lines. Cysteine protease cathepsin B, Cysteine proteinase, lipid transfer protein and Aquaporin were observed as drought-regulated proteins participating in hydrolysis and transmembrane transport. The activities of phospholipid hydroperoxide glutathione peroxidase, peroxiredoxin, dehydroascorbate reductase, peroxisomal ascorbate peroxidase and monodehydroascorbate reductase associated with alleviating the accumulation of reactive oxygen species in stress inducing environments. Our results showed that drought-responsive proteins were closely related to metabolic processes including signal transduction, antioxidant defenses, hydrolysis, and transmembrane transport. PMID:28910323

Fatty acids identified in the Burmese python promote beneficial cardiac growth.

PubMed

Riquelme, Cecilia A; Magida, Jason A; Harrison, Brooke C; Wall, Christopher E; Marr, Thomas G; Secor, Stephen M; Leinwand, Leslie A

2011-10-28

Burmese pythons display a marked increase in heart mass after a large meal. We investigated the molecular mechanisms of this physiological heart growth with the goal of applying this knowledge to the mammalian heart. We found that heart growth in pythons is characterized by myocyte hypertrophy in the absence of cell proliferation and by activation of physiological signal transduction pathways. Despite high levels of circulating lipids, the postprandial python heart does not accumulate triglycerides or fatty acids. Instead, there is robust activation of pathways of fatty acid transport and oxidation combined with increased expression and activity of superoxide dismutase, a cardioprotective enzyme. We also identified a combination of fatty acids in python plasma that promotes physiological heart growth when injected into either pythons or mice.

Therapeutic angiogenesis: angiogenic growth factors for ischemic heart disease.

PubMed

Henning, Robert J

2016-09-01

Stem cells encode vascular endothelial growth factors (VEGFs), fibroblastic growth factors (FGFs), stem cell factor, stromal cell-derived factor, platelet growth factor and angiopoietin that can contribute to myocardial vascularization. VEGFs and FGFs are the most investigated growth factors. VEGFs regulate angiogenesis and vasculogenesis. FGFs stimulate vessel cell proliferation and differentiation and are regulators of endothelial cell migration, proliferation and survival. Clinical trials of VEGF or FGF for myocardial angiogenesis have produced disparate results. The efficacy of therapeutic angiogenesis can be improved by: (1) identifying the most optimal patients; (2) increased knowledge of angiogenic factor pharmacokinetics and proper dose; (3) prolonging contact of angiogenic factors with the myocardium; (4) increasing the efficiency of VEGF or FGF gene transduction; and (5) utilizing PET or MRI to measure myocardial perfusion and perfusion reserve.

Light Signaling in Bud Outgrowth and Branching in Plants

PubMed Central

Leduc, Nathalie; Roman, Hanaé; Barbier, François; Péron, Thomas; Huché-Thélier, Lydie; Lothier, Jérémy; Demotes-Mainard, Sabine; Sakr, Soulaiman

2014-01-01

Branching determines the final shape of plants, which influences adaptation, survival and the visual quality of many species. It is an intricate process that includes bud outgrowth and shoot extension, and these in turn respond to environmental cues and light conditions. Light is a powerful environmental factor that impacts multiple processes throughout plant life. The molecular basis of the perception and transduction of the light signal within buds is poorly understood and undoubtedly requires to be further unravelled. This review is based on current knowledge on bud outgrowth-related mechanisms and light-mediated regulation of many physiological processes. It provides an extensive, though not exhaustive, overview of the findings related to this field. In parallel, it points to issues to be addressed in the near future. PMID:27135502

Dragging ras back in the ring.

PubMed

Stephen, Andrew G; Esposito, Dominic; Bagni, Rachel K; McCormick, Frank

2014-03-17

Ras proteins play a major role in human cancers but have not yielded to therapeutic attack. Ras-driven cancers are among the most difficult to treat and often excluded from therapies. The Ras proteins have been termed "undruggable," based on failures from an era in which understanding of signaling transduction, feedback loops, redundancy, tumor heterogeneity, and Ras' oncogenic role was poor. Structures of Ras oncoproteins bound to their effectors or regulators are unsolved, and it is unknown precisely how Ras proteins activate their downstream targets. These knowledge gaps have impaired development of therapeutic strategies. A better understanding of Ras biology and biochemistry, coupled with new ways of targeting undruggable proteins, is likely to lead to new ways of defeating Ras-driven cancers. Copyright © 2014 Elsevier Inc. All rights reserved.

High-accuracy biodistribution analysis of adeno-associated virus variants by double barcode sequencing.

PubMed

Marsic, Damien; Méndez-Gómez, Héctor R; Zolotukhin, Sergei

2015-01-01

Biodistribution analysis is a key step in the evaluation of adeno-associated virus (AAV) capsid variants, whether natural isolates or produced by rational design or directed evolution. Indeed, when screening candidate vectors, accurate knowledge about which tissues are infected and how efficiently is essential. We describe the design, validation, and application of a new vector, pTR-UF50-BC, encoding a bioluminescent protein, a fluorescent protein and a DNA barcode, which can be used to visualize localization of transduction at the organism, organ, tissue, or cellular levels. In addition, by linking capsid variants to different barcoded versions of the vector and amplifying the barcode region from various tissue samples using barcoded primers, biodistribution of viral genomes can be analyzed with high accuracy and efficiency.

Translational neurocardiology: preclinical models and cardioneural integrative aspects

PubMed Central

Andresen, M. C.; Armour, J. A.; Billman, G. E.; Chen, P.‐S.; Foreman, R. D.; Herring, N.; O'Leary, D. S.; Sabbah, H. N.; Schultz, H. D.; Sunagawa, K.; Zucker, I. H.

2016-01-01

Abstract Neuronal elements distributed throughout the cardiac nervous system, from the level of the insular cortex to the intrinsic cardiac nervous system, are in constant communication with one another to ensure that cardiac output matches the dynamic process of regional blood flow demand. Neural elements in their various ‘levels’ become differentially recruited in the transduction of sensory inputs arising from the heart, major vessels, other visceral organs and somatic structures to optimize neuronal coordination of regional cardiac function. This White Paper will review the relevant aspects of the structural and functional organization for autonomic control of the heart in normal conditions, how these systems remodel/adapt during cardiac disease, and finally how such knowledge can be leveraged in the evolving realm of autonomic regulation therapy for cardiac therapeutics. PMID:27098459

Knowledge of the Effects of Indoor Air Quality on Health among Women in Jordan

ERIC Educational Resources Information Center

Madanat, Hala; Barnes, Michael D.; Cole, Eugene C.

2008-01-01

Objective: To assess the extent of knowledge about symptoms relating to respiratory illnesses and home environments among a random sample of 200 urban Jordanian women. Method: This customized, validated, cross-sectional questionnaire evaluated the knowledge of these women about the association between the indoor environment and health, the…

QSIA--A Web-Based Environment for Learning, Assessing and Knowledge Sharing in Communities

ERIC Educational Resources Information Center

Rafaeli, Sheizaf; Barak, Miri; Dan-Gur, Yuval; Toch, Eran

2004-01-01

This paper describes a Web-based and distributed system named QSIA that serves as an environment for learning, assessing and knowledge sharing. QSIA--Questions Sharing and Interactive Assignments--offers a unified infrastructure for developing, collecting, managing and sharing of knowledge items. QSIA enhances collaboration in authoring via online…

Collaborative Learning and Knowledge-Construction through a Knowledge-Based WWW Authoring Tool.

ERIC Educational Resources Information Center

Haugsjaa, Erik

This paper outlines hurdles to using the World Wide Web for learning, specifically in a collaborative knowledge-construction environment. Theoretical solutions based directly on existing Web environments, as well as on research and system prototypes in the areas of Intelligent Tutoring Systems (ITS) and ITS authoring systems, are suggested. Topics…

An Adaptive Approach to Managing Knowledge Development in a Project-Based Learning Environment

ERIC Educational Resources Information Center

Tilchin, Oleg; Kittany, Mohamed

2016-01-01

In this paper we propose an adaptive approach to managing the development of students' knowledge in the comprehensive project-based learning (PBL) environment. Subject study is realized by two-stage PBL. It shapes adaptive knowledge management (KM) process and promotes the correct balance between personalized and collaborative learning. The…

Software support environment design knowledge capture

NASA Technical Reports Server (NTRS)

Dollman, Tom

1990-01-01

The objective of this task is to assess the potential for using the software support environment (SSE) workstations and associated software for design knowledge capture (DKC) tasks. This assessment will include the identification of required capabilities for DKC and hardware/software modifications needed to support DKC. Several approaches to achieving this objective are discussed and interim results are provided: (1) research into the problem of knowledge engineering in a traditional computer-aided software engineering (CASE) environment, like the SSE; (2) research into the problem of applying SSE CASE tools to develop knowledge based systems; and (3) direct utilization of SSE workstations to support a DKC activity.

Phage transposon mutagenesis.

PubMed

Siegrist, M Sloan; Rubin, Eric J

2009-01-01

Phage transduction is an attractive method of genetic manipulation in mycobacteria. PhiMycoMarT7 is well suited for transposon mutagenesis as it is temperature sensitive for replication and contains T7 promoters that promote transcription, a highly active transposase gene, and an Escherichia coli oriR6 K origin of replication. Mycobacterial transposon mutant libraries produced by PhiMycoMarT7 transduction are amenable to both forward and reverse genetic studies. In this protocol, we detail the preparation of PhiMycoMarT7, including a description of the phage, reconstitution of the phage, purification of plaques, preparation of phage stock, and titering of phage stock. We then describe the transduction procedure and finally outline the isolation of individual transposon mutants.

MDA5 and LGP2: Accomplices and Antagonists of Antiviral Signal Transduction

PubMed Central

Rodriguez, Kenny R.; Bruns, Annie M.

2014-01-01

Mammalian cells have the ability to recognize virus infection and mount a powerful antiviral transcriptional response that provides an initial barrier to replication and impacts both innate and adaptive immune responses. Retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) proteins mediate intracellular virus recognition and are activated by viral RNA ligands to induce antiviral signal transduction. While the mechanisms of RIG-I regulation are already well understood, less is known about the more enigmatic melanoma differentiation-associated 5 (MDA5) and laboratory of genetics and physiology 2 (LGP2). Emerging evidence suggests that these two RLRs are intimately associated as both accomplices and antagonists of antiviral signal transduction. PMID:24850739

Signal transduction networks in rheumatoid arthritis

PubMed Central

Hammaker, D; Sweeney, S; Firestein, G

2003-01-01

Signal transduction pathways regulate cellular responses to stress and play a critical role in inflammation. The complexity and specificity of signalling mechanisms represent major hurdles for developing effective, safe therapeutic interventions that target specific molecules. One approach is to dissect the pathways methodically to determine their hierarchy in various cell types and diseases. This approach contributed to the identification and prioritisation of specific kinases that regulate NF-κB and the mitogen activated protein (MAP) kinase cascade as especially attractive targets. Although significant issues remain with regard to the discovery of truly selective kinase inhibitors, the risks that accompany inhibition of fundamental signal transduction mechanisms can potentially be decreased by careful dissection of the pathways and rational target selection. PMID:14532158

Cancer classification through filtering progressive transductive support vector machine based on gene expression data

NASA Astrophysics Data System (ADS)

Lu, Xinguo; Chen, Dan

2017-08-01

Traditional supervised classifiers neglect a large amount of data which not have sufficient follow-up information, only work with labeled data. Consequently, the small sample size limits the advancement of design appropriate classifier. In this paper, a transductive learning method which combined with the filtering strategy in transductive framework and progressive labeling strategy is addressed. The progressive labeling strategy does not need to consider the distribution of labeled samples to evaluate the distribution of unlabeled samples, can effective solve the problem of evaluate the proportion of positive and negative samples in work set. Our experiment result demonstrate that the proposed technique have great potential in cancer prediction based on gene expression.

Promoting Students' Problem Solving Skills and Knowledge of STEM Concepts in a Data-Rich Learning Environment: Using Online Data as a Tool for Teaching about Renewable Energy Technologies

NASA Astrophysics Data System (ADS)

Thurmond, Brandi

This study sought to compare a data-rich learning (DRL) environment that utilized online data as a tool for teaching about renewable energy technologies (RET) to a lecture-based learning environment to determine the impact of the learning environment on students' knowledge of Science, Technology, Engineering, and Math (STEM) concepts related to renewable energy technologies and students' problem solving skills. Two purposefully selected Advanced Placement (AP) Environmental Science teachers were included in the study. Each teacher taught one class about RET in a lecture-based environment (control) and another class in a DRL environment (treatment), for a total of four classes of students (n=128). This study utilized a quasi-experimental, pretest/posttest, control-group design. The initial hypothesis that the treatment group would have a significant gain in knowledge of STEM concepts related to RET and be better able to solve problems when compared to the control group was not supported by the data. Although students in the DRL environment had a significant gain in knowledge after instruction, posttest score comparisons of the control and treatment groups revealed no significant differences between the groups. Further, no significant differences were noted in students' problem solving abilities as measured by scores on a problem-based activity and self-reported abilities on a reflective questionnaire. This suggests that the DRL environment is at least as effective as the lecture-based learning environment in teaching AP Environmental Science students about RET and fostering the development of problem solving skills. As this was a small scale study, further research is needed to provide information about effectiveness of DRL environments in promoting students' knowledge of STEM concepts and problem-solving skills.

Virtual Knowledge Brokering: Describing the Roles and Strategies Used by Knowledge Brokers in a Pediatric Physiotherapy Virtual Community of Practice.

PubMed

Hurtubise, Karen; Rivard, Lisa; Héguy, Léa; Berbari, Jade; Camden, Chantal

2016-01-01

Knowledge transfer in pediatric rehabilitation is challenging and requires active, multifaceted strategies. The use of knowledge brokers (KBs) is one such strategy noted to promote clinician behavior change. The success of using KBs to transfer knowledge relies on their ability to adapt to ever-changing clinical contexts. In addition, with the rapid growth of online platforms as knowledge transfer forums, KBs must become effective in virtual environments. Although the role of KBs has been studied in various clinical contexts, their emerging role in specific online environments designed to support evidence-based behavior change has not yet been described. Our objective is to describe the roles of, and strategies used by, four KBs involved in a virtual community of practice to guide and inform future online KB interventions. A descriptive design guided this study and a thematic content analysis process was used to analyze online KB postings. The Promoting Action on Research in Health Sciences knowledge transfer framework and online andragogical learning theories assisted in the coding. A thematic map was created illustrating the links between KBs' strategies and emerging roles in the virtual environment. We analyzed 95 posts and identified three roles: 1) context architect: promoting a respectful learning environment, 2) knowledge sharing promoter: building capacity, and 3) linkage creator: connecting research-to-practice. Strategies used by KBs reflected invitational, constructivism, and connectivism approaches, with roles and strategies changing over time. This study increases our understanding of the actions of KBs in virtual contexts to foster uptake of research evidence in pediatric physiotherapy. Our results provide valuable information about the knowledge and skills required by individuals to fulfill this role in virtual environments.

Molecular cloning and characterization of G alpha proteins from the western tarnished plant bug, Lygus hesperus

USDA-ARS?s Scientific Manuscript database

The G-alpha subunits of heterotrimeric G proteins play critical roles in the activation of diverse signal transduction cascades. However, the role of these genes in chemosensation remains to be fully elucidated. To initiate a comprehensive survey of signal transduction genes, we used homology-base...

STANDARDIZATION AND VALIDATION OF ADENOVIRAL TRANSDUCTION OF AN ANDROGEN RECEPTOR POSITIVE CELL LINE WITH AN MMTV-LUC REPORTER FOR ENDOCRINE SCREENING

EPA Science Inventory

Standardization and Validation of Adenoviral Transduction of an Androgen Receptor Positive Cell Line with an MMTV-Luc Reporter for Endocrine Screening P. Hartig, K . Bobseine,
M. Cardon, C. Lambright and L. E. Gray, Jr. USEPA, Reproductive Toxicology Division, NHEERL, RTP, NC...

Mechanisms of signal transduction by ethylene: overlapping and non-overlapping signalling roles in a receptor family

PubMed Central

Shakeel, Samina N.; Wang, Xiaomin; Binder, Brad M.; Schaller, G. Eric

2013-01-01

The plant hormone ethylene regulates growth and development as well as responses to biotic and abiotic stresses. Over the last few decades, key elements involved in ethylene signal transduction have been identified through genetic approaches, these elements defining a pathway that extends from initial ethylene perception at the endoplasmic reticulum to changes in transcriptional regulation within the nucleus. Here, we present our current understanding of ethylene signal transduction, focusing on recent developments that support a model with overlapping and non-overlapping roles for members of the ethylene receptor family. We consider the evidence supporting this model for sub-functionalization within the receptor family, and then discuss mechanisms by which such a sub-functionalization may occur. To this end, we consider the importance of receptor interactions in modulating their signal output and how such interactions vary in the receptor family. In addition, we consider evidence indicating that ethylene signal output by the receptors involves both phosphorylation-dependent and phosphorylation-independent mechanisms. We conclude with a current model for signalling by the ethylene receptors placed within the overall context of ethylene signal transduction. PMID:23543258

Restoring functional neurofibromin by protein transduction.

PubMed

Mellert, K; Lechner, S; Lüdeke, M; Lamla, M; Möller, P; Kemkemer, R; Scheffzek, K; Kaufmann, D

2018-04-18

In Neurofibromatosis 1 (NF1) germ line loss of function mutations result in reduction of cellular neurofibromin content (NF1+/-, NF1 haploinsufficiency). The Ras-GAP neurofibromin is a very large cytoplasmic protein (2818 AA, 319 kDa) involved in the RAS-MAPK pathway. Aside from regulation of proliferation, it is involved in mechanosensoric of cells. We investigated neurofibromin replacement in cultured human fibroblasts showing reduced amount of neurofibromin. Full length neurofibromin was produced recombinantly in insect cells and purified. Protein transduction into cultured fibroblasts was performed employing cell penetrating peptides along with photochemical internalization. This combination of transduction strategies ensures the intracellular uptake and the translocation to the cytoplasm of neurofibromin. The transduced neurofibromin is functional, indicated by functional rescue of reduced mechanosensoric blindness and reduced RasGAP activity in cultured fibroblasts of NF1 patients or normal fibroblasts treated by NF1 siRNA. Our study shows that recombinant neurofibromin is able to revert cellular effects of NF1 haploinsuffiency in vitro, indicating a use of protein transduction into cells as a potential treatment strategy for the monogenic disease NF1.

Transduction of NeuroD2 protein induced neural cell differentiation.

PubMed

Noda, Tomohide; Kawamura, Ryuzo; Funabashi, Hisakage; Mie, Masayasu; Kobatake, Eiry

2006-11-01

NeuroD2, one of the neurospecific basic helix-loop-helix transcription factors, has the ability to induce neural differentiation in undifferentiated cells. In this paper, we show that transduction of NeuroD2 protein induced mouse neuroblastoma cell line N1E-115 into neural differentiation. NeuroD2 has two basic-rich domains, one is nuclear localization signal (NLS) and the other is basic region of basic helix-loop-helix (basic). We constructed some mutants of NeuroD2, ND2(Delta100-115) (lack of NLS), ND2(Delta123-134) (lack of basic) and ND2(Delta100-134) (lack of both NLS and basic) for transduction experiments. Using these proteins, we have shown that NLS region of NeuroD2 plays a role of protein transduction. Continuous addition of NeuroD2 protein resulted in N1E-115 cells adopting neural morphology after 4 days and Tau mRNA expression was increased. These results suggest that neural differentiation can be induced by direct addition of NeuroD2 protein.

A functional in vivo screen for regulators of tumor progression identifies HOXB2 as a regulator of tumor growth in breast cancer.

PubMed

Boimel, Pamela J; Cruz, Cristian; Segall, Jeffrey E

2011-09-01

Microarray profiling in breast cancer patients has identified genes correlated with prognosis whose functions are unknown. The purpose of this study was to develop an in vivo assay for functionally screening regulators of tumor progression using a mouse model. Transductant shRNA cell lines were made in the MDA-MB-231 breast cancer line. A pooled population of 25 transductants was injected into the mammary fat pads and tail veins of mice to evaluate tumor growth, and experimental metastasis. The proportions of transductants were evaluated in the tumor and metastases using barcodes specific to each shRNA transductant. We characterized the homeobox 2 transcription factor as a negative regulator, decreasing tumor growth in MDA-MB-231, T47D, and MTLn3 mammary adenocarcinoma cell lines. Homeobox genes have been correlated with cancer patient prognosis and tumorigenesis. Here we use a novel in vivo shRNA screen to identify a new role for a homeobox gene in human mammary adenocarcinoma. Copyright © 2011 Elsevier Inc. All rights reserved.

A functional in vivo screen for regulators of tumor progression identifies HOXB2 as a regulator of tumor growth in breast cancer

PubMed Central

Boimel, Pamela J.; Cruz, Cristian; Segall, Jeffrey E.

2011-01-01

Microarray profiling in breast cancer patients have identified genes correlated with prognosis whose functions are unknown. The purpose of this study was to develop an in vivo assay for functionally screening regulators of tumor progression using a mouse model. Transductant shRNA cell lines were made in the MDA-MB-231 breast cancer line. A pooled population of 25 transductants was injected into the mammary fat pads and tail veins of mice to evaluate tumor growth, and experimental metastasis. The proportions of transductants were evaluated in the tumor and metastases using barcodes specific to each shRNA transductant. We characterized the homeobox 2 transcription factor as a negative regulator, decreasing tumor growth in MDA-MB-231, T47D, and MTLn3 mammary adenocarcinoma cell lines. Homeobox genes have been correlated with cancer patient prognosis and tumorigenesis. Here we use a novel in vivo shRNA screen to identify a new role for a homeobox gene in human mammary adenocarcinoma. PMID:21672623

Receptor clustering affects signal transduction at the membrane level in the reaction-limited regime

NASA Astrophysics Data System (ADS)

Caré, Bertrand R.; Soula, Hédi A.

2013-01-01

Many types of membrane receptors are found to be organized as clusters on the cell surface. We investigate the potential effect of such receptor clustering on the intracellular signal transduction stage. We consider a canonical pathway with a membrane receptor (R) activating a membrane-bound intracellular relay protein (G). We use Monte Carlo simulations to recreate biochemical reactions using different receptor spatial distributions and explore the dynamics of the signal transduction. Results show that activation of G by R is severely impaired by R clustering, leading to an apparent blunted biological effect compared to control. Paradoxically, this clustering decreases the half maximal effective dose (ED50) of the transduction stage, increasing the apparent affinity. We study an example of inter-receptor interaction in order to account for possible compensatory effects of clustering and observe the parameter range in which such interactions slightly counterbalance the loss of activation of G. The membrane receptors’ spatial distribution affects the internal stages of signal amplification, suggesting a functional role for membrane domains and receptor clustering independently of proximity-induced receptor-receptor interactions.

Fyn is a redox sensor involved in solar ultraviolet light-induced signal transduction in skin carcinogenesis.

PubMed

Kim, J-E; Roh, E; Lee, M H; Yu, D H; Kim, D J; Lim, T-G; Jung, S K; Peng, C; Cho, Y-Y; Dickinson, S; Alberts, D; Bowden, G T; Einspahr, J; Stratton, S P; Curiel-Lewandrowski, C; Bode, A M; Lee, K W; Dong, Z

2016-08-04

Solar ultraviolet (UV) light is a major etiological factor in skin carcinogenesis, with solar UV-stimulated signal transduction inducing pathological changes and skin damage. The primary sensor of solar UV-induced cellular signaling has not been identified. We use an experimental system of solar simulated light (SSL) to mimic solar UV and we demonstrate that Fyn is a primary redox sensor involved in SSL-induced signal transduction. Reactive oxygen species (ROS) generated by SSL exposure directly oxidize Cys488 of Fyn, resulting in increased Fyn kinase activity. Fyn oxidation was increased in mouse skin after SSL exposure and Fyn-knockout mice formed larger and more tumors compared with Fyn wild-type mice when exposed to SSL for an extended period of time. Murine embryonic fibroblasts (MEFs) lacking Fyn and cells in which Fyn expression was knocked down were resistant to SSL-induced apoptosis. Furthermore, cells expressing mutant Fyn (C448A) were resistant to SSL-induced apoptosis. These findings suggest that Fyn acts as a regulatory nexus between solar UV, ROS and signal transduction during skin carcinogenesis.

40 CFR 312.28 - Specialized knowledge or experience on the part of the defendant.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 27 2010-07-01 2010-07-01 false Specialized knowledge or experience on the part of the defendant. 312.28 Section 312.28 Protection of Environment ENVIRONMENTAL PROTECTION... knowledge or experience on the part of the defendant. (a) Persons to whom this part is applicable per § 312...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kubo, Yoshinao; Yoshii, Hiroaki; Kamiyama, Haruka

Ezrin, radixin, and moesin (ERM) proteins supply functional linkage between integral membrane proteins and cytoskeleton in mammalian cells to regulate membrane protein dynamisms and cytoskeleton rearrangement. To assess potential role of the ERM proteins in HIV-1 lifecycle, we examined if suppression of ERM function in human cells expressing HIV-1 infection receptors influences HIV-1 envelope (Env)-mediated HIV-1-vector transduction and cell-cell fusion. Expression of an ezrin dominant negative mutant or knockdown of ezrin, radixin, or moesin with siRNA uniformly decreased transduction titers of HIV-1 vectors having X4-tropic Env. In contrast, transduction titers of R5-tropic Env HIV-1 vectors were decreased only by radixinmore » knockdown: ezrin knockdown had no detectable effects and moesin knockdown rather increased transduction titer. Each of the ERM suppressions had no detectable effects on cell surface expression of CD4, CCR5, and CXCR4 or VSV-Env-mediated HIV-1 vector transductions. Finally, the individual knockdown of ERM mRNAs uniformly decreased efficiency of cell-cell fusion mediated by X4- or R5-tropic Env and HIV-1 infection receptors. These results suggest that (i) the ERM proteins function as positive regulators of infection by X4-tropic HIV-1, (ii) moesin additionally functions as a negative regulator of R5-tropic HIV-1 virus infection at the early step(s) after the membrane fusion, and (iii) receptor protein dynamisms are regulated differently in R5- and X4-tropic HIV-1 infections.« less

Molecular analysis of vector genome structures after liver transduction by conventional and self-complementary adeno-associated viral serotype vectors in murine and nonhuman primate models.

PubMed

Sun, Xun; Lu, You; Bish, Lawrence T; Calcedo, Roberto; Wilson, James M; Gao, Guangping

2010-06-01

Vectors based on several new adeno-associated viral (AAV) serotypes demonstrated strong hepatocyte tropism and transduction efficiency in both small- and large-animal models for liver-directed gene transfer. Efficiency of liver transduction by AAV vectors can be further improved in both murine and nonhuman primate (NHP) animals when the vector genomes are packaged in a self-complementary (sc) format. In an attempt to understand potential molecular mechanism(s) responsible for enhanced transduction efficiency of the sc vector in liver, we performed extensive molecular studies of genome structures of conventional single-stranded (ss) and sc AAV vectors from liver after AAV gene transfer in both mice and NHPs. These included treatment with exonucleases with specific substrate preferences, single-cutter restriction enzyme digestion and polarity-specific hybridization-based vector genome mapping, and bacteriophage phi29 DNA polymerase-mediated and double-stranded circular template-specific rescue of persisted circular genomes. In mouse liver, vector genomes of both genome formats seemed to persist primarily as episomal circular forms, but sc vectors converted into circular forms more rapidly and efficiently. However, the overall differences in vector genome abundance and structure in the liver between ss and sc vectors could not account for the remarkable differences in transduction. Molecular structures of persistent genomes of both ss and sc vectors were significantly more heterogeneous in macaque liver, with noticeable structural rearrangements that warrant further characterizations.

Molecular Analysis of Vector Genome Structures After Liver Transduction by Conventional and Self-Complementary Adeno-Associated Viral Serotype Vectors in Murine and Nonhuman Primate Models

PubMed Central

Sun, Xun; Lu, You; Bish, Lawrence T.; Calcedo, Roberto; Wilson, James M.

2010-01-01

Abstract Vectors based on several new adeno-associated viral (AAV) serotypes demonstrated strong hepatocyte tropism and transduction efficiency in both small- and large-animal models for liver-directed gene transfer. Efficiency of liver transduction by AAV vectors can be further improved in both murine and nonhuman primate (NHP) animals when the vector genomes are packaged in a self-complementary (sc) format. In an attempt to understand potential molecular mechanism(s) responsible for enhanced transduction efficiency of the sc vector in liver, we performed extensive molecular studies of genome structures of conventional single-stranded (ss) and sc AAV vectors from liver after AAV gene transfer in both mice and NHPs. These included treatment with exonucleases with specific substrate preferences, single-cutter restriction enzyme digestion and polarity-specific hybridization-based vector genome mapping, and bacteriophage ϕ29 DNA polymerase-mediated and double-stranded circular template-specific rescue of persisted circular genomes. In mouse liver, vector genomes of both genome formats seemed to persist primarily as episomal circular forms, but sc vectors converted into circular forms more rapidly and efficiently. However, the overall differences in vector genome abundance and structure in the liver between ss and sc vectors could not account for the remarkable differences in transduction. Molecular structures of persistent genomes of both ss and sc vectors were significantly more heterogeneous in macaque liver, with noticeable structural rearrangements that warrant further characterizations. PMID:20113166

No Evidence for Ionotropic Pheromone Transduction in the Hawkmoth Manduca sexta.

PubMed

Nolte, Andreas; Gawalek, Petra; Koerte, Sarah; Wei, HongYing; Schumann, Robin; Werckenthin, Achim; Krieger, Jürgen; Stengl, Monika

2016-01-01

Insect odorant receptors (ORs) are 7-transmembrane receptors with inverse membrane topology. They associate with the conserved ion channel Orco. As chaperon, Orco maintains ORs in cilia and, as pacemaker channel, Orco controls spontaneous activity in olfactory receptor neurons. Odorant binding to ORs opens OR-Orco receptor ion channel complexes in heterologous expression systems. It is unknown, whether this also occurs in vivo. As an alternative to this ionotropic transduction, experimental evidence is accumulating for metabotropic odor transduction, implicating that insect ORs couple to G-proteins. Resulting second messengers gate various ion channels. They generate the sensillum potential that elicits phasic-tonic action potentials (APs) followed by late, long-lasting pheromone responses. Because it is still unclear how and when Orco opens after odor-OR-binding, we used tip recordings to examine in vivo the effects of the Orco antagonist OLC15 and the amilorides MIA and HMA on bombykal transduction in the hawkmoth Manduca sexta. In contrast to OLC15 both amilorides decreased the pheromone-dependent sensillum potential amplitude and the frequency of the phasic AP response. Instead, OLC15 decreased spontaneous activity, increased latencies of phasic-, and decreased frequencies of late, long-lasting pheromone responses Zeitgebertime-dependently. Our results suggest no involvement for Orco in the primary transduction events, in contrast to amiloride-sensitive channels. Instead of an odor-gated ionotropic receptor, Orco rather acts as a voltage- and apparently second messenger-gated pacemaker channel controlling the membrane potential and hence threshold and kinetics of the pheromone response.

Exploring transduction mechanisms of protein transduction domains (PTDs) in living cells utilizing single-quantum dot tracking (SQT) technology.

PubMed

Suzuki, Yasuhiro

2012-01-01

Specific protein domains known as protein transduction domains (PTDs) can permeate cell membranes and deliver proteins or bioactive materials into living cells. Various approaches have been applied for improving their transduction efficacy. It is, therefore, crucial to clarify the entry mechanisms and to identify the rate-limiting steps. Because of technical limitations for imaging PTD behavior on cells with conventional fluorescent-dyes, how PTDs enter the cells has been a topic of much debate. Utilizing quantum dots (QDs), we recently tracked the behavior of PTD that was derived from HIV-1 Tat (TatP) in living cells at the single-molecule level with 7-nm special precision. In this review article, we initially summarize the controversy on TatP entry mechanisms; thereafter, we will focus on our recent findings on single-TatP-QD tracking (SQT), to identify the major sequential steps of intracellular delivery in living cells and to discuss how SQT can easily provide direct information on TatP entry mechanisms. As a primer for SQT study, we also discuss the latest findings on single particle tracking of various molecules on the plasma membrane. Finally, we discuss the problems of QDs and the challenges for the future in utilizing currently available QD probes for SQT. In conclusion, direct identification of the rate-limiting steps of PTD entry with SQT should dramatically improve the methods for enhancing transduction efficiency.

Establishment of an AAV Reverse Infection-Based Array

PubMed Central

Wang, Gang; Dong, Zheyue; Shen, Wei; Zheng, Gang; Wu, Xiaobing; Xue, Jinglun; Wang, Yue; Chen, Jinzhong

2010-01-01

Background The development of a convenient high-throughput gene transduction approach is critical for biological screening. Adeno-associated virus (AAV) vectors are broadly used in gene therapy studies, yet their applications in in vitro high-throughput gene transduction are limited. Principal Findings We established an AAV reverse infection (RI)-based method in which cells were transduced by quantified recombinant AAVs (rAAVs) pre-coated onto 96-well plates. The number of pre-coated rAAV particles and number of cells loaded per well, as well as the temperature stability of the rAAVs on the plates, were evaluated. As the first application of this method, six serotypes or hybrid serotypes of rAAVs (AAV1, AAV2, AAV5/5, AAV8, AAV25 m, AAV28 m) were compared for their transduction efficiencies using various cell lines, including BHK21, HEK293, BEAS-2BS, HeLaS3, Huh7, Hepa1-6, and A549. AAV2 and AAV1 displayed high transduction efficiency; thus, they were deemed to be suitable candidate vectors for the RI-based array. We next evaluated the impact of sodium butyrate (NaB) treatment on rAAV vector-mediated reporter gene expression and found it was significantly enhanced, suggesting that our system reflected the biological response of target cells to specific treatments. Conclusions/Significance Our study provides a novel method for establishing a highly efficient gene transduction array that may be developed into a platform for cell biological assays. PMID:20976058

Lunar Plant Biology - A Review of the Apollo Era

NASA Astrophysics Data System (ADS)

Ferl, Robert J.; Paul, Anna-Lisa

2010-04-01

Recent plans for human return to the Moon have significantly elevated scientific interest in the lunar environment with emphasis on the science to be done in preparation for the return and while on the lunar surface. Since the return to the Moon is envisioned as a dedicated and potentially longer-term commitment to lunar exploration, questions of the lunar environment and particularly its impact on biology and biological systems have become a significant part of the lunar science discussion. Plants are integral to the discussion of biology on the Moon. Plants are envisioned as important components of advanced habitats and fundamental components of advanced life-support systems. Moreover, plants are sophisticated multicellular eukaryotic life-forms with highly orchestrated developmental processes, well-characterized signal transduction pathways, and exceedingly fine-tuned responses to their environments. Therefore, plants represent key test organisms for understanding the biological impact of the lunar environment on terrestrial life-forms. Indeed, plants were among the initial and primary organisms that were exposed to returned lunar regolith from the Apollo lunar missions. This review discusses the original experiments involving plants in association with the Apollo samples, with the intent of understanding those studies within the context of the first lunar exploration program and drawing from those experiments the data to inform the studies critical within the next lunar exploration science agenda.

Lunar plant biology--a review of the Apollo era.

PubMed

Ferl, Robert J; Paul, Anna-Lisa

2010-04-01

Recent plans for human return to the Moon have significantly elevated scientific interest in the lunar environment with emphasis on the science to be done in preparation for the return and while on the lunar surface. Since the return to the Moon is envisioned as a dedicated and potentially longer-term commitment to lunar exploration, questions of the lunar environment and particularly its impact on biology and biological systems have become a significant part of the lunar science discussion. Plants are integral to the discussion of biology on the Moon. Plants are envisioned as important components of advanced habitats and fundamental components of advanced life-support systems. Moreover, plants are sophisticated multicellular eukaryotic life-forms with highly orchestrated developmental processes, well-characterized signal transduction pathways, and exceedingly fine-tuned responses to their environments. Therefore, plants represent key test organisms for understanding the biological impact of the lunar environment on terrestrial life-forms. Indeed, plants were among the initial and primary organisms that were exposed to returned lunar regolith from the Apollo lunar missions. This review discusses the original experiments involving plants in association with the Apollo samples, with the intent of understanding those studies within the context of the first lunar exploration program and drawing from those experiments the data to inform the studies critical within the next lunar exploration science agenda.

HOG MAP kinase regulation of alternariol biosynthesis in Alternaria alternata is important for substrate colonization.

PubMed

Graf, Eva; Schmidt-Heydt, Markus; Geisen, Rolf

2012-07-16

Strains of the genus Alternaria are ubiquitously present and frequently found on fruits, vegetables and cereals. One of the most commonly found species from this genus is A. alternata which is able to produce the mycotoxin alternariol among others. To date only limited knowledge is available about the regulation of the biosynthesis of alternariol, especially under conditions relevant to food. Tomatoes are a typical substrate of A. alternata and have a high water activity. On the other hand cereals with moderate water activity are also frequently colonized by A. alternata. In the current analysis it was demonstrated that even minor changes in the osmotic status of the substrate affect the alternariol biosynthesis of strains from vegetables resulting in nearly complete inhibition. High osmolarity in the environment is usually transmitted to the transcriptional level of downstream regulated genes by the HOG signal cascade (high osmolarity glycerol cascade) which is a MAP kinase transduction pathway. The phosphorylation status of the A. alternata HOG (AaHOG) was determined. Various concentrations of NaCl induce the phosphorylation of AaHOG in a concentration, time and strain dependent manner. A strain with a genetically inactivated aahog gene was no longer able to produce alternariol indicating that the activity of the aahog gene is required for alternariol biosynthesis. Further experiments revealed that the biosynthesis of alternariol is important for the fungus to colonize tomato tissue. The tight water activity dependent regulation of alternariol biosynthesis ensures alternariol biosynthesis at conditions which indicate an optimal colonization substrate for the fungus. Copyright © 2012 Elsevier B.V. All rights reserved.

The effect of Chinese Jinzhida recipe on the hippocampus in a rat model of diabetes-associated cognitive decline

PubMed Central

2013-01-01

Background To investigate the effects of treatment with Multi component Chinese Medicine Jinzhida (JZD) on behavioral deficits in diabetes-associated cognitive decline (DACD) rats and verify our hypothesis that JZD treatment improves cognitive function by suppressing the endoplasmic reticulum stress (ERS) and improving insulin signaling transduction in the rats’ hippocampus. Methods A rat model of type 2 diabetes mellitus (T2DM) was established using high fat diet and streptozotocin (30 mg/kg, ip). Insulin sensitivity was evaluated by the oral glucose tolerance test and the insulin tolerance test. After 7 weeks, the T2DM rats were treated with JZD. The step-down test and Morris water maze were used to evaluate behavior in T2DM rats after 5 weeks of treatment with JZD. Levels of phosphorylated proteins involved in the ERS and in insulin signaling transduction pathways were assessed by Western blot for T2DM rats’ hippocampus. Results Compared to healthy control rats, T2DM rats initially showed insulin resistance and had declines in acquisition and retrieval processes in the step-down test and in spatial memory in the Morris water maze after 12 weeks. Performance on both the step-down test and Morris water maze tasks improved after JZD treatment. In T2DM rats, the ERS was activated, and then inhibited the insulin signal transduction pathways through the Jun NH2-terminal kinases (JNK) mediated. JZD treatment suppressed the ERS, increased insulin signal transduction, and improved insulin resistance in the rats’ hippocampus. Conclusions Treatment with JZD improved cognitive function in the T2DM rat model. The possible mechanism for DACD was related with ERS inducing the insulin signal transduction dysfunction in T2DM rats’ hippocampus. The JZD could reduce ERS and improve insulin signal transduction and insulin resistance in T2DM rats’ hippocampus and as a result improved the cognitive function. PMID:23829668

Defining Specificity Determinants of cGMP Mediated Gustatory Sensory Transduction in Caenorhabditis elegans

PubMed Central

Smith, Heidi K.; Luo, Linjiao; O’Halloran, Damien; Guo, Dagang; Huang, Xin-Yun; Samuel, Aravinthan D. T.; Hobert, Oliver

2013-01-01

Cyclic guanosine monophosphate (cGMP) is a key secondary messenger used in signal transduction in various types of sensory neurons. The importance of cGMP in the ASE gustatory receptor neurons of the nematode Caenorhabditis elegans was deduced by the observation that multiple receptor-type guanylyl cyclases (rGCs), encoded by the gcy genes, and two presently known cyclic nucleotide-gated ion channel subunits, encoded by the tax-2 and tax-4 genes, are essential for ASE-mediated gustatory behavior. We describe here specific mechanistic features of cGMP-mediated signal transduction in the ASE neurons. First, we assess the specificity of the sensory functions of individual rGC proteins. We have previously shown that multiple rGC proteins are expressed in a left/right asymmetric manner in the functionally lateralized ASE neurons and are required to sense distinct salt cues. Through domain swap experiments among three different rGC proteins, we show here that the specificity of individual rGC proteins lies in their extracellular domains and not in their intracellular, signal-transducing domains. Furthermore, we find that rGC proteins are also sufficient to confer salt sensory responses to other neurons. Both findings support the hypothesis that rGC proteins are salt receptor proteins. Second, we identify a novel, likely downstream effector of the rGC proteins in gustatory signal transduction, a previously uncharacterized cyclic nucleotide-gated (CNG) ion channel, encoded by the che-6 locus. che-6 mutants show defects in gustatory sensory transduction that are similar to defects observed in animals lacking the tax-2 and tax-4 CNG channels. In contrast, thermosensory signal transduction, which also requires tax-2 and tax-4, does not require che-6, but requires another CNG, cng-3. We propose that CHE-6 may form together with two other CNG subunits, TAX-2 and TAX-4, a gustatory neuron-specific heteromeric CNG channel complex. PMID:23695300

Enrichment of human hematopoietic stem/progenitor cells facilitates transduction for stem cell gene therapy.

PubMed

Baldwin, Kismet; Urbinati, Fabrizia; Romero, Zulema; Campo-Fernandez, Beatriz; Kaufman, Michael L; Cooper, Aaron R; Masiuk, Katelyn; Hollis, Roger P; Kohn, Donald B

2015-05-01

Autologous hematopoietic stem cell (HSC) gene therapy for sickle cell disease has the potential to treat this illness without the major immunological complications associated with allogeneic transplantation. However, transduction efficiency by β-globin lentiviral vectors using CD34-enriched cell populations is suboptimal and large vector production batches may be needed for clinical trials. Transducing a cell population more enriched for HSC could greatly reduce vector needs and, potentially, increase transduction efficiency. CD34(+) /CD38(-) cells, comprising ∼1%-3% of all CD34(+) cells, were isolated from healthy cord blood CD34(+) cells by fluorescence-activated cell sorting and transduced with a lentiviral vector expressing an antisickling form of beta-globin (CCL-β(AS3) -FB). Isolated CD34(+) /CD38(-) cells were able to generate progeny over an extended period of long-term culture (LTC) compared to the CD34(+) cells and required up to 40-fold less vector for transduction compared to bulk CD34(+) preparations containing an equivalent number of CD34(+) /CD38(-) cells. Transduction of isolated CD34(+) /CD38(-) cells was comparable to CD34(+) cells measured by quantitative PCR at day 14 with reduced vector needs, and average vector copy/cell remained higher over time for LTC initiated from CD34(+) /38(-) cells. Following in vitro erythroid differentiation, HBBAS3 mRNA expression was similar in cultures derived from CD34(+) /CD38(-) cells or unfractionated CD34(+) cells. In vivo studies showed equivalent engraftment of transduced CD34(+) /CD38(-) cells when transplanted in competition with 100-fold more CD34(+) /CD38(+) cells. This work provides initial evidence for the beneficial effects from isolating human CD34(+) /CD38(-) cells to use significantly less vector and potentially improve transduction for HSC gene therapy. © 2015 AlphaMed Press.

Signaling Network of Environmental Sensing and Adaptation in Plants:. Key Roles of Calcium Ion

NASA Astrophysics Data System (ADS)

Kurusu, Takamitsu; Kuchitsu, Kazuyuki

2011-01-01

Considering the important issues concerning food, environment, and energy that humans are facing in the 21st century, humans mostly depend on plants. Unlike animals which move from an inappropriate environment, plants do not move, but rapidly sense diverse environmental changes or invasion by other organisms such as pathogens and insects in the place they root, and adapt themselves by changing their own bodies, through which they developed adaptability. Whole genetic information corresponding to the blueprints of many biological systems has recently been analyzed, and comparative genomic studies facilitated tracing strategies of each organism in their evolutional processes. Comparison of factors involved in intracellular signal transduction between animals and plants indicated diversification of different gene sets. Reversible binding of Ca2+ to sensor proteins play key roles as a molecular switch both in animals and plants. Molecular mechanisms for signaling network of environmental sensing and adaptation in plants will be discussed with special reference to Ca2+ as a key element in information processing.

Learning in 3D Virtual Environments: Collaboration and Knowledge Spirals

ERIC Educational Resources Information Center

Burton, Brian G.; Martin, Barbara N.

2010-01-01

The purpose of this case study was to determine if learning occurred within a 3D virtual learning environment by determining if elements of collaboration and Nonaka and Takeuchi's (1995) knowledge spiral were present. A key portion of this research was the creation of a Virtual Learning Environment. This 3D VLE utilized the Torque Game Engine…

Knowledge 'Translation' as social learning: negotiating the uptake of research-based knowledge in practice.

PubMed

Salter, K L; Kothari, A

2016-02-29

Knowledge translation and evidence-based practice have relied on research derived from clinical trials, which are considered to be methodologically rigorous. The result is practice recommendations based on a narrow view of evidence. We discuss how, within a practice environment, in fact individuals adopt and apply new evidence derived from multiple sources through ongoing, iterative learning cycles. The discussion is presented in four sections. After elaborating on the multiple forms of evidence used in practice, in section 2 we argue that the practitioner derives contextualized knowledge through reflective practice. Then, in section 3, the focus shifts from the individual to the team with consideration of social learning and theories of practice. In section 4 we discuss the implications of integrative and negotiated knowledge exchange and generation within the practice environment. Namely, how can we promote the use of research within a team-based, contextualized knowledge environment? We suggest support for: 1) collaborative learning environments for active learning and reflection, 2) engaged scholarship approaches so that practice can inform research in a collaborative manner and 3) leveraging authoritative opinion leaders for their clinical expertise during the shared negotiation of knowledge and research. Our approach also points to implications for studying evidence-informed practice: the identification of practice change (as an outcome) ought to be supplemented with understandings of how and when social negotiation processes occur to achieve integrated knowledge. This article discusses practice knowledge as dependent on the practice context and on social learning processes, and suggests how research knowledge uptake might be supported from this vantage point.

Promoting Students' Problem Solving Skills and Knowledge of STEM Concepts in a Data-Rich Learning Environment: Using Online Data as a Tool for Teaching about Renewable Energy Technologies

ERIC Educational Resources Information Center

Thurmond, Brandi

2011-01-01

This study sought to compare a data-rich learning (DRL) environment that utilized online data as a tool for teaching about renewable energy technologies (RET) to a lecture-based learning environment to determine the impact of the learning environment on students' knowledge of Science, Technology, Engineering, and Math (STEM) concepts related…

Information Professional or IT Professional?: The Knowledge and Skills Required by Academic Librarians in the Digital Library Environment

ERIC Educational Resources Information Center

Raju, Jaya

2017-01-01

As library and information science (LIS) becomes an increasingly technology-driven profession, particularly in the academic library environment, questions arise as to the extent of information technology (IT) knowledge and skills that LIS professionals require. The purpose of this paper is to ascertain what IT knowledge and skills are needed by…

Identification of the Competencies, Knowledge, and Skills Needed by School Nutrition Assistants in the Current Environment

ERIC Educational Resources Information Center

Nettles, Mary Frances; Carr, Deborah H.; Cater, Jerry B.; Federico, Holly A.

2009-01-01

Purpose/Objectives: Study objectives were to identify the functional areas, competencies, knowledge, and skills needed by effective school nutrition (SN) assistants in the current SN environment, and determine at what point the SN assistant should be able to know/perform the knowledge/skill statement, at time of hire or after training. Methods: In…

Inquiry into Chemotherapy-Induced P53 Activation in Cancer Cells as a Model for Teaching Signal Transduction

ERIC Educational Resources Information Center

Srougi, Melissa C.; Carson, Susan

2013-01-01

Intracellular and extracellular communication is conducted through an intricate and interwoven network of signal transduction pathways. The mechanisms for how cells speak with one another are of significant biological importance to both basic and industrial scientists from a number of different disciplines. We have therefore developed and…

Beacon Editor: Capturing Signal Transduction Pathways Using the Systems Biology Graphical Notation Activity Flow Language.

PubMed

Elmarakeby, Haitham; Arefiyan, Mostafa; Myers, Elijah; Li, Song; Grene, Ruth; Heath, Lenwood S

2017-12-01

The Beacon Editor is a cross-platform desktop application for the creation and modification of signal transduction pathways using the Systems Biology Graphical Notation Activity Flow (SBGN-AF) language. Prompted by biologists' requests for enhancements, the Beacon Editor includes numerous powerful features for the benefit of creation and presentation.

Pantropic retroviruses as a transduction tool for sea urchin embryos

PubMed Central

Core, Amanda B.; Reyna, Arlene E.; Conaway, Evan A.; Bradham, Cynthia A.

2012-01-01

Sea urchins are an important model for experiments at the intersection of development and systems biology, and technical innovations that enhance the utility of this model are of great value. This study explores pantropic retroviruses as a transduction tool for sea urchin embryos, and demonstrates that pantropic retroviruses infect sea urchin embryos with high efficiency and genomically integrate at a copy number of one per cell. We successfully used a self-inactivation strategy to both insert a sea urchin-specific enhancer and disrupt the endogenous viral enhancer. The resulting self-inactivating viruses drive global and persistent gene expression, consistent with genomic integration during the first cell cycle. Together, these data provide substantial proof of principle for transduction technology in sea urchin embryos. PMID:22431628

A parallel algorithm for multi-level logic synthesis using the transduction method. M.S. Thesis

NASA Technical Reports Server (NTRS)

Lim, Chieng-Fai

1991-01-01

The Transduction Method has been shown to be a powerful tool in the optimization of multilevel networks. Many tools such as the SYLON synthesis system (X90), (CM89), (LM90) have been developed based on this method. A parallel implementation is presented of SYLON-XTRANS (XM89) on an eight processor Encore Multimax shared memory multiprocessor. It minimizes multilevel networks consisting of simple gates through parallel pruning, gate substitution, gate merging, generalized gate substitution, and gate input reduction. This implementation, called Parallel TRANSduction (PTRANS), also uses partitioning to break large circuits up and performs inter- and intra-partition dynamic load balancing. With this, good speedups and high processor efficiencies are achievable without sacrificing the resulting circuit quality.

Calcium/Calmodulin-Mediated Gravitropic Response in Plants

NASA Technical Reports Server (NTRS)

Poovaiah, B. W.

2002-01-01

Plant organs respond to different physical signals such as gravity, light and touch. Gravity gives plants proper orientation, resulting in the proper form that we take for granted; the roots grow down into soil and shoots grow towards the light. Under microgravity conditions, as in space, plant growth patterns lack a clear sense of direction. Calcium and calmodulin (CaM) play an important role in gravity signal transduction. However, the molecular and biochemical mechanisms involved in gravity signal transduction are not clearly understood. The goal of this project was to gain a fundamental understanding of how calcium/calmodulin-mediated signaling is involved in gravity signal transduction in plants. During the grant period, significant progress was made in elucidating the role of calmodulin and its target proteins in gravitropism.

The ethylene signal transduction pathway in Arabidopsis

NASA Technical Reports Server (NTRS)

Kieber, J. J.; Evans, M. L. (Principal Investigator)

1997-01-01

The gaseous hormone ethylene is an important regulator of plant growth and development. Using a simple response of etiolated seedlings to ethylene as a genetic screen, genes involved in ethylene signal transduction have been identified in Arabidopsis. Analysis of two of these genes that have been cloned reveals that ethylene signalling involves a combination of a protein (ETR1) with similarity to bacterial histidine kinases and a protein (CTR1) with similarity to Raf-1, a protein kinase involved in multiple signalling cascades in eukaryotic cells. Several lines of investigation provide compelling evidence that ETR1 encodes an ethylene receptor. For the first time there is a glimpse of the molecular circuitry underlying the signal transduction pathway for a plant hormone.

Signal transduction and amplification through enzyme-triggered ligand release and accelerated catalysis.

PubMed

Goggins, Sean; Marsh, Barrie J; Lubben, Anneke T; Frost, Christopher G

2015-08-01

Signal transduction and signal amplification are both important mechanisms used within biological signalling pathways. Inspired by this process, we have developed a signal amplification methodology that utilises the selectivity and high activity of enzymes in combination with the robustness and generality of an organometallic catalyst, achieving a hybrid biological and synthetic catalyst cascade. A proligand enzyme substrate was designed to selectively self-immolate in the presence of the enzyme to release a ligand that can bind to a metal pre-catalyst and accelerate the rate of a transfer hydrogenation reaction. Enzyme-triggered catalytic signal amplification was then applied to a range of catalyst substrates demonstrating that signal amplification and signal transduction can both be achieved through this methodology.

On-chip optical transduction scheme for graphene nano-electro-mechanical systems in silicon-photonic platform.

PubMed

Dash, Aneesh; Selvaraja, S K; Naik, A K

2018-02-15

We present a scheme for on-chip optical transduction of strain and displacement of graphene-based nano-electro-mechanical systems (NEMS). A detailed numerical study on the feasibility of three silicon-photonic integrated circuit configurations is presented: the Mach-Zehnder interferometer (MZI), the micro-ring resonator, and the ring-loaded MZI. An index sensing based technique using an MZI loaded with a ring resonator with a moderate Q-factor of 2400 can yield a sensitivity of 28  fm/Hz and 6.5×10 -6 %/Hz for displacement and strain, respectively. Though any phase-sensitive integrated-photonic device could be used for optical transduction, here we show that optimal sensitivity is achievable by combining resonance with phase sensitivity.

On-chip optical transduction scheme for graphene nano-electro-mechanical systems in silicon-photonic platform

NASA Astrophysics Data System (ADS)

Dash, Aneesh; Selvaraja, S. K.; Naik, A. K.

2018-02-01

We present a scheme for on-chip optical transduction of strain and displacement of Graphene-based Nano-Electro-Mechanical Systems (NEMS). A detailed numerical study on the feasibility of three silicon-photonic integrated circuit configurations is presented: Mach-Zehnder Interferometer(MZI), micro-ring resonator and ring-loaded MZI. An index-sensing based technique using a Mach-Zehnder Interferometer loaded with a ring resonator with a moderate Q-factor of 2400 can yield a sensitivity of 28 fm/sqrt(Hz), and 6.5E-6 %/sqrt(Hz) for displacement and strain respectively. Though any phase sensitive integrated photonic device could be used for optical transduction, here we show that optimal sensitivity is achievable by combining resonance with phase sensitivity.

Designing computer learning environments for engineering and computer science: The scaffolded knowledge integration framework

NASA Astrophysics Data System (ADS)

Linn, Marcia C.

1995-06-01

Designing effective curricula for complex topics and incorporating technological tools is an evolving process. One important way to foster effective design is to synthesize successful practices. This paper describes a framework called scaffolded knowledge integration and illustrates how it guided the design of two successful course enhancements in the field of computer science and engineering. One course enhancement, the LISP Knowledge Integration Environment, improved learning and resulted in more gender-equitable outcomes. The second course enhancement, the spatial reasoning environment, addressed spatial reasoning in an introductory engineering course. This enhancement minimized the importance of prior knowledge of spatial reasoning and helped students develop a more comprehensive repertoire of spatial reasoning strategies. Taken together, the instructional research programs reinforce the value of the scaffolded knowledge integration framework and suggest directions for future curriculum reformers.

Photic niche invasions: phylogenetic history of the dim-light foraging augochlorine bees (Halictidae)

PubMed Central

Tierney, Simon M.; Sanjur, Oris; Grajales, Grethel G.; Santos, Leandro M.; Bermingham, Eldredge; Wcislo, William T.

2012-01-01

Most bees rely on flowering plants and hence are diurnal foragers. From this ancestral state, dim-light foraging in bees requires significant adaptations to a new photic environment. We used DNA sequences to evaluate the phylogenetic history of the most diverse clade of Apoidea that is adapted to dim-light environments (Augochlorini: Megalopta, Megaloptidia and Megommation). The most speciose lineage, Megalopta, is distal to the remaining dim-light genera, and its closest diurnal relative (Xenochlora) is recovered as a lineage that has secondarily reverted to diurnal foraging. Tests for adaptive protein evolution indicate that long-wavelength opsin shows strong evidence of stabilizing selection, with no more than five codons (2%) under positive selection, depending on analytical procedure. In the branch leading to Megalopta, the amino acid of the single positively selected codon is conserved among ancestral Halictidae examined, and is homologous to codons known to influence molecular structure at the chromophore-binding pocket. Theoretically, such mutations can shift photopigment λmax sensitivity and enable visual transduction in alternate photic environments. Results are discussed in light of the available evidence on photopigment structure, morphological specialization and biogeographic distributions over geological time. PMID:21795273

Photic niche invasions: phylogenetic history of the dim-light foraging augochlorine bees (Halictidae).

PubMed

Tierney, Simon M; Sanjur, Oris; Grajales, Grethel G; Santos, Leandro M; Bermingham, Eldredge; Wcislo, William T

2012-02-22

Most bees rely on flowering plants and hence are diurnal foragers. From this ancestral state, dim-light foraging in bees requires significant adaptations to a new photic environment. We used DNA sequences to evaluate the phylogenetic history of the most diverse clade of Apoidea that is adapted to dim-light environments (Augochlorini: Megalopta, Megaloptidia and Megommation). The most speciose lineage, Megalopta, is distal to the remaining dim-light genera, and its closest diurnal relative (Xenochlora) is recovered as a lineage that has secondarily reverted to diurnal foraging. Tests for adaptive protein evolution indicate that long-wavelength opsin shows strong evidence of stabilizing selection, with no more than five codons (2%) under positive selection, depending on analytical procedure. In the branch leading to Megalopta, the amino acid of the single positively selected codon is conserved among ancestral Halictidae examined, and is homologous to codons known to influence molecular structure at the chromophore-binding pocket. Theoretically, such mutations can shift photopigment λ(max) sensitivity and enable visual transduction in alternate photic environments. Results are discussed in light of the available evidence on photopigment structure, morphological specialization and biogeographic distributions over geological time.

Electromagnetic Acoustic Transducers for Robotic Nondestructive Inspection in Harsh Environments.

PubMed

Choi, Sungho; Cho, Hwanjeong; Lindsey, Matthew S; Lissenden, Cliff J

2018-01-11

Elevated temperature, gamma radiation, and geometric constraints inside dry storage casks for spent nuclear fuel represent a harsh environment for nondestructive inspection of the cask and require that the inspection be conducted with a robotic system. Electromagnetic acoustic transducers (EMATs) using non-contact ultrasonic transduction based on the Lorentz force to excite/receive ultrasonic waves are suited for use in the robotic inspection. Periodic permanent magnet EMATs that actuate/receive shear horizontal guided waves are developed for application to robotic nondestructive inspection of stress corrosion cracks in the heat affected zone of welds in stainless steel dry storage canisters. The EMAT's components are carefully selected in consideration of the inspection environment, and tested under elevated temperature and gamma radiation doses up to 177 °C and 5920 krad, respectively, to evaluate the performance of the EMATs under realistic environmental conditions. The effect of gamma radiation is minimal, but the EMAT's performance is affected by temperatures above 121 °C due to the low Curie temperature of the magnets. Different magnets are needed to operate at 177 °C. The EMAT's capability to detect notches is also evaluated from B-scan measurements on 304 stainless steel welded plate containing surface-breaking notches.

PDZ-containing proteins: alternative splicing as a source of functional diversity.

PubMed

Sierralta, Jimena; Mendoza, Carolina

2004-12-01

Scaffold proteins allow specific protein complexes to be assembled in particular regions of the cell at which they organize subcellular structures and signal transduction complexes. This characteristic is especially important for neurons, which are highly polarized cells. Among the domains contained by scaffold proteins, the PSD-95, Discs-large, ZO-1 (PDZ) domains are of particular relevance in signal transduction processes and maintenance of neuronal and epithelial polarity. These domains are specialized in the binding of the carboxyl termini of proteins allowing membrane proteins to be localized by the anchoring to the cytoskeleton mediated by PDZ-containing scaffold proteins. In vivo studies carried out in Drosophila have taught that the role of many scaffold proteins is not limited to a single process; thus, in many cases the same genes are expressed in different tissues and participate in apparently very diverse processes. In addition to the differential expression of interactors of scaffold proteins, the expression of variants of these molecular scaffolds as the result of the alternative processing of the genes that encode them is proving to be a very important source of variability and complexity on a main theme. Alternative splicing in the nervous system is well documented, where specific isoforms play roles in neurotransmission, ion channel function, neuronal cell recognition, and are developmentally regulated making it a major mechanism of functional diversity. Here we review the current state of knowledge about the diversity and the known function of PDZ-containing proteins in Drosophila with emphasis in the role played by alternatively processed forms in the diversity of functions attributed to this family of proteins.

Nitric oxide and phytohormone interactions: current status and perspectives

PubMed Central

Freschi, Luciano

2013-01-01

Nitric oxide (NO) is currently considered a ubiquitous signal in plant systems, playing significant roles in a wide range of responses to environmental and endogenous cues. During the signaling events leading to these plant responses, NO frequently interacts with plant hormones and other endogenous molecules, at times originating remarkably complex signaling cascades. Accumulating evidence indicates that virtually all major classes of plant hormones may influence, at least to some degree, the endogenous levels of NO. In addition, studies conducted during the induction of diverse plant responses have demonstrated that NO may also affect biosynthesis, catabolism/conjugation, transport, perception, and/or transduction of different phytohormones, such as auxins, gibberellins, cytokinins, abscisic acid, ethylene, salicylic acid, jasmonates, and brassinosteroids. Although still not completely elucidated, the mechanisms underlying the interaction between NO and plant hormones have recently been investigated in a number of species and plant responses. This review specifically focuses on the current knowledge of the mechanisms implicated in NO–phytohormone interactions during the regulation of developmental and metabolic plant events. The modifications triggered by NO on the transcription of genes encoding biosynthetic/degradative enzymes as well as proteins involved in the transport and signal transduction of distinct plant hormones will be contextualized during the control of developmental, metabolic, and defense responses in plants. Moreover, the direct post-translational modification of phytohormone biosynthetic enzymes and receptors through S-nitrosylation will also be discussed as a key mechanism for regulating plant physiological responses. Finally, some future perspectives toward a more complete understanding of NO–phytohormone interactions will also be presented and discussed. PMID:24130567

ATRIAL NATRIURETIC FACTOR RECEPTOR GUANYLATE CYCLASE SIGNALING: NEW ATP- REGULATED TRANSDUCTION MOTIF

PubMed Central

Duda, Teresa; Bharill, Shashank; Wojtas, Ireneusz; Yadav, Prem; Gryczynski, Ignacy; Gryczynski, Zygmunt; Sharma, Rameshwar K.

2010-01-01

ANF-RGC$ membrane guanylate cyclase is the receptor for the hypotensive peptide hormones, atrial natriuretic factor (ANF) and type B natriuretic peptide (BNP). It is a single transmembrane spanning protein. Binding the hormone to the extracellular domain activates its intracellular catalytic domain. This results in accelerated production of cyclic GMP, a second messenger in controlling blood pressure, cardiac vasculature and fluid secretion. ATP is the obligatory transducer of the ANF signal. It works through its ATP regulated module, ARM, which is juxtaposed to the C-terminal side of the transmembrane domain. Upon interaction, ATP induces a cascade of temporal and spatial changes in the ARM, which, finally, result in activation of the catalytic module. Although the exact nature and the details of these changes are not known, some of these have been stereographed in the simulated three-dimensional model of the ARM and validated biochemically. Through comprehensive techniques ofsteady-state, time-resolved tryptophan fluorescence and Forster Resonance Energy Transfer (FRET), site-directed and deletion-mutagenesis, and reconstitution, the present study validates and explains themechanism of the model-based predicted transduction role of the ARM’s structural motif, 669WTAPELL675. This motif is critical in the ATP-dependent ANF signaling. Molecular modeling shows that ATP binding exposes the 669WTAPELL675 motif, the exposure, in turn, facilitates its interaction and activation of the catalytic module. These principles of the model have been experimentally validated. This knowledge brings us a step closer to our understanding of the mechanism by which the ATP-dependent spatial changes within the ARM cause ANF signaling of ANF-RGC. PMID:19137266

Establishment of an immortalized cell line derived from the prairie vole via lentivirus-mediated transduction of mutant cyclin-dependent kinase 4, cyclin D, and telomerase reverse transcriptase

PubMed Central

Katayama, Masafumi; Kiyono, Tohru; Horie, Kengo; Hirayama, Takashi; Eitsuka, Takahiro; Kuroda, Kengo; Donai, Kenichiro; Hidema, Shizu; Nishimori, Katsuhiko; Fukuda, Tomokazu

2015-01-01

The prairie vole (Microtus ochrogaster) shows social behaviors such as monogamy and parenting of infants with pair bonding. These social behaviors are specific to the prairie vole and have not been observed in other types of voles, such as mountain voles. Although the prairie vole has several unique characteristics, an in vitro cell culture system has not been established for this species. Furthermore, establishment of cultured cells derived from the prairie vole may be beneficial based on the three Rs (i.e., Replacement, Reduction, and Refinement) concept. Therefore, in this study, we attempted to establish an immortalized cell line derived from the prairie vole. Our previous research has shown that transduction with mutant forms of cyclin-dependent kinase 4 (CDK4), cyclin D, and telomerase reverse transcriptase (TERT) could efficiently immortalize cells from multiple species, including humans, cattle, pigs, and monkeys. Here, we introduced these three genes into prairie vole-derived muscle fibroblasts. The expression of mutant CDK4 and cyclin D proteins was confirmed by western blotting, and telomerase activity was detected in immortalized vole muscle-derived fibroblasts (VMF-K4DT cells or VMFs) by stretch PCR. Population doubling analysis showed that the introduction of mutant CDK4, cyclin D, and TERT extended the lifespan of VMFs. To the best of our knowledge, this is the first report describing the establishment of an immortalized cell line derived from the prairie vole through the expression of mutant CDK4, cyclin D, and human TERT. PMID:26496927

Establishment of an immortalized cell line derived from the prairie vole via lentivirus-mediated transduction of mutant cyclin-dependent kinase 4, cyclin D, and telomerase reverse transcriptase.

PubMed

Katayama, Masafumi; Kiyono, Tohru; Horie, Kengo; Hirayama, Takashi; Eitsuka, Takahiro; Kuroda, Kengo; Donai, Kenichiro; Hidema, Shizu; Nishimori, Katsuhiko; Fukuda, Tomokazu

2016-01-01

The prairie vole (Microtus ochrogaster) shows social behaviors such as monogamy and parenting of infants with pair bonding. These social behaviors are specific to the prairie vole and have not been observed in other types of voles, such as mountain voles. Although the prairie vole has several unique characteristics, an in vitro cell culture system has not been established for this species. Furthermore, establishment of cultured cells derived from the prairie vole may be beneficial based on the three Rs (i.e., Replacement, Reduction, and Refinement) concept. Therefore, in this study, we attempted to establish an immortalized cell line derived from the prairie vole. Our previous research has shown that transduction with mutant forms of cyclin-dependent kinase 4 (CDK4), cyclin D, and telomerase reverse transcriptase (TERT) could efficiently immortalize cells from multiple species, including humans, cattle, pigs, and monkeys. Here, we introduced these three genes into prairie vole-derived muscle fibroblasts. The expression of mutant CDK4 and cyclin D proteins was confirmed by western blotting, and telomerase activity was detected in immortalized vole muscle-derived fibroblasts (VMF-K4DT cells or VMFs) by stretch PCR. Population doubling analysis showed that the introduction of mutant CDK4, cyclin D, and TERT extended the lifespan of VMFs. To the best of our knowledge, this is the first report describing the establishment of an immortalized cell line derived from the prairie vole through the expression of mutant CDK4, cyclin D, and human TERT.

Systematic mapping of two component response regulators to gene targets in a model sulfate reducing bacterium

PubMed Central

2011-01-01

Background Two component regulatory systems are the primary form of signal transduction in bacteria. Although genomic binding sites have been determined for several eukaryotic and bacterial transcription factors, comprehensive identification of gene targets of two component response regulators remains challenging due to the lack of knowledge of the signals required for their activation. We focused our study on Desulfovibrio vulgaris Hildenborough, a sulfate reducing bacterium that encodes unusually diverse and largely uncharacterized two component signal transduction systems. Results We report the first systematic mapping of the genes regulated by all transcriptionally acting response regulators in a single bacterium. Our results enabled functional predictions for several response regulators and include key processes of carbon, nitrogen and energy metabolism, cell motility and biofilm formation, and responses to stresses such as nitrite, low potassium and phosphate starvation. Our study also led to the prediction of new genes and regulatory networks, which found corroboration in a compendium of transcriptome data available for D. vulgaris. For several regulators we predicted and experimentally verified the binding site motifs, most of which were discovered as part of this study. Conclusions The gene targets identified for the response regulators allowed strong functional predictions to be made for the corresponding two component systems. By tracking the D. vulgaris regulators and their motifs outside the Desulfovibrio spp. we provide testable hypotheses regarding the functions of orthologous regulators in other organisms. The in vitro array based method optimized here is generally applicable for the study of such systems in all organisms. PMID:21992415

Mechanisms of resistance to imatinib in CML patients: a paradigm for the advantages and pitfalls of molecularly targeted therapy.

PubMed

Ritchie, E; Nichols, G

2006-12-01

One of the challenges of cancer therapeutics is to discover targets unique to the tumor cell population. Constitutively activated tyrosine kinases play a role in the malignant phenotype in a number of different cancers. While the kinases may be present in the normal cell, the cancer cell is often dependent upon the activation of the kinase for the maintenance of malignant growth. Inhibition of kinase activation may therefore selectively inhibit malignant proliferation. In the case of chronic myelogenous leukemia (CML), the activated tyrosine kinase (BCR-ABL) is due to a chromosomal translocation that defines this disease, and is necessary for malignant transformation. Imatinib mesylate (Gleevec, Novartis) is a small molecule tyrosine kinase inhibitor, developed through the chemical modification to be selected for a small number of tyrosine kinases present in human cells. This agent is also orally bioavailable and has been found to be effective in clinical trials. We have learned much through the clinical use of this agent. 1) Specific targeting of activated signal transduction pathways may be effective in inhibiting cancer cells. 2) Cancer cells may not only be inherently resistant to small molecule inhibitors, but may also develop resistance after exposure to the inhibitor. 3) Increased knowledge regarding critical signal transduction pathways, the structure of the molecules that are being targeted and the inhibitors themselves, will allow us to understand resistance as it develops and create new molecules to bypass resistance. We will discuss imatinib as an important example of the success and pitfalls of targeted therapeutics for cancer.

Nonlinear Ultrasonic Measurements in Nuclear Reactor Environments

NASA Astrophysics Data System (ADS)

Reinhardt, Brian T.

Several Department of Energy Office of Nuclear Energy (DOE-NE) programs, such as the Fuel Cycle Research and Development (FCRD), Advanced Reactor Concepts (ARC), Light Water Reactor Sustainability, and Next Generation Nuclear Power Plants (NGNP), are investigating new fuels, materials, and inspection paradigms for advanced and existing reactors. A key objective of such programs is to understand the performance of these fuels and materials during irradiation. In DOE-NE's FCRD program, ultrasonic based technology was identified as a key approach that should be pursued to obtain the high-fidelity, high-accuracy data required to characterize the behavior and performance of new candidate fuels and structural materials during irradiation testing. The radiation, high temperatures, and pressure can limit the available tools and characterization methods. In this thesis, two ultrasonic characterization techniques will be explored. The first, finite amplitude wave propagation has been demonstrated to be sensitive to microstructural material property changes. It is a strong candidate to determine fuel evolution; however, it has not been demonstrated for in-situ reactor applications. In this thesis, finite amplitude wave propagation will be used to measure the microstructural evolution in Al-6061. This is the first demonstration of finite amplitude wave propagation at temperatures in excess of 200 °C and during an irradiation test. Second, a method based on contact nonlinear acoustic theory will be developed to identify compressed cracks. Compressed cracks are typically transparent to ultrasonic wave propagation; however, by measuring harmonic content developed during finite amplitude wave propagation, it is shown that even compressed cracks can be characterized. Lastly, piezoelectric transducers capable of making these measurements are developed. Specifically, three piezoelectric sensors (Bismuth Titanate, Aluminum Nitride, and Zinc Oxide) are tested in the Massachusetts Institute of Technology Research reactor to a fast neutron fluence of 8.65x10 20 n/cm2. It is demonstrated that Bismuth Titanate is capable of transduction up to 5 x1020 n/cm2, Zinc Oxide is capable of transduction up to 6.27 x1020 n/cm 2, and Aluminum Nitride is capable of transduction up to 8.65x x10 20 n/cm2.

The Effect of a Multimedia Learning Environment on the Knowledge, Attitude, Confidence, and Skill of Dental Hygiene Students

ERIC Educational Resources Information Center

Stegeman, Cynthia A.

2011-01-01

The purpose of this study was to compare the effects of a student-centered, interactive, case-based, multimedia learning environment to a traditional tutorial-based, multimedia learning environment on second-year dental hygiene students (n = 29). Surveys were administered at four points to measure attainment and retention of knowledge, attitude,…

Continuous medical education (CME): do we need CME for paediatric environmental medicine in Europe?

PubMed

Boese-O'Reilly, Stephan

2007-10-01

The knowledge about the influence of environmental hazards on children's health is increasing enormously. European Ministers of Health and Environment, like many other stakeholders, identified the environmental hazards in Europe for the health of children as so serious, that they called for a "Children's Environment and Health Action Plan for Europe (CEHAPE)" approved in June 2004. The knowledge of paediatricians and other health care providers on children's health and environment in Europe is insufficient, due to the lack of training in environmental medicine for medical students, clinical trainees and postgraduates. Only continuous medical education in environmental medicine can help to fill this gap of knowledge and is thereby urgently needed. The World Health Organization developed a training package for health care providers for children's health and environment, containing excellent material for paediatric training events. The International Network on Children's Health, Environment and Safety (INCHES) developed additional training material for paediatricians within the Children's Health, Environment and Safety Training (CHEST) project. The German Network Children's Health and Environment offers training for paediatric doctors' assistants in primary prevention. To improve knowledge about children's health and environment at all levels in paediatric settings, greater efforts of national institutions, paediatric associations and other institutions are necessary. It is time to strengthen existing structures and to introduce, where necessary, new structures for training in environmental medicine.

Calcium/Calmodulin-Mediated Gravitropic Response in Plants

NASA Technical Reports Server (NTRS)

Poovaiah, B. W.

2002-01-01

The goal of this project was to gain a fundamental understanding of how calcium/calmodulin-mediated signaling is involved in gravity signal transduction in plants. During the period of support, significant progress was made in elucidating the role of calmodulin and its target proteins in gravitropism. This laboratory has made breakthroughs by cloning and characterizing genes that are involved in calcium/calmodulin-mediated signaling. Some of these genes show altered expression under hypergravity and simulated microgravity conditions. A major advance was made in our attempts to understand gravity signal transduction by cloning and characterizing a catalase which requires calcium/calmodulin for its activation. Our results suggest that calcium/calmodulin have dual roles in regulating the level of hydrogen peroxide (H202), a signal molecule that plays a major role in gravitropism. It is well established that auxin plays a major role in gravitropism. Our results indicate that there is a 'cross-talk' between calcium/calmodulin-mediated signaling and auxin-mediated signal transduction. Auxin-regulated SAUR proteins that are involved in gravitropism bind to calmodulin in a calcium-dependent manner. A novel chimeric calcium/calmodulin-dependent protein kinase was cloned and characterized and its role in gravity signal transduction was investigated. These studies have provided some answers to the fundamental questions about how signal molecules such as calcium, H202, and hormones such as auxin bring about the ultimate gravitropic response and the integral role of calmodulin in gravity signal transduction. This NASA-funded study has led to some spinoffs that have applications in solving agricultural problems. The Washington State University Research Foundation has obtained several patents related to this work.

Ganglioside structure dictates signal transduction by cholera toxin and association with caveolae-like membrane domains in polarized epithelia.

PubMed

Wolf, A A; Jobling, M G; Wimer-Mackin, S; Ferguson-Maltzman, M; Madara, J L; Holmes, R K; Lencer, W I

1998-05-18

In polarized cells, signal transduction by cholera toxin (CT) requires apical endocytosis and retrograde transport into Golgi cisternae and perhaps ER (Lencer, W.I., C. Constable, S. Moe, M. Jobling, H.M. Webb, S. Ruston, J.L. Madara, T. Hirst, and R. Holmes. 1995. J. Cell Biol. 131:951-962). In this study, we tested whether CT's apical membrane receptor ganglioside GM1 acts specifically in toxin action. To do so, we used CT and the related Escherichia coli heat-labile type II enterotoxin LTIIb. CT and LTIIb distinguish between gangliosides GM1 and GD1a at the cell surface by virtue of their dissimilar receptor-binding B subunits. The enzymatically active A subunits, however, are homologous. While both toxins bound specifically to human intestinal T84 cells (Kd approximately 5 nM), only CT elicited a cAMP-dependent Cl- secretory response. LTIIb, however, was more potent than CT in eliciting a cAMP-dependent response from mouse Y1 adrenal cells (toxic dose 10 vs. 300 pg/well). In T84 cells, CT fractionated with caveolae-like detergent-insoluble membranes, but LTIIb did not. To investigate further the relationship between the specificity of ganglioside binding and partitioning into detergent-insoluble membranes and signal transduction, CT and LTIIb chimeric toxins were prepared. Analysis of these chimeric toxins confirmed that toxin-induced signal transduction depended critically on the specificity of ganglioside structure. The mechanism(s) by which ganglioside GM1 functions in signal transduction likely depends on coupling CT with caveolae or caveolae-related membrane domains.

Release of GTP Exchange Factor Mediated Down-Regulation of Abscisic Acid Signal Transduction through ABA-Induced Rapid Degradation of RopGEFs

PubMed Central

Waadt, Rainer; Schroeder, Julian I.

2016-01-01

The phytohormone abscisic acid (ABA) is critical to plant development and stress responses. Abiotic stress triggers an ABA signal transduction cascade, which is comprised of the core components PYL/RCAR ABA receptors, PP2C-type protein phosphatases, and protein kinases. Small GTPases of the ROP/RAC family act as negative regulators of ABA signal transduction. However, the mechanisms by which ABA controls the behavior of ROP/RACs have remained unclear. Here, we show that an Arabidopsis guanine nucleotide exchange factor protein RopGEF1 is rapidly sequestered to intracellular particles in response to ABA. GFP-RopGEF1 is sequestered via the endosome-prevacuolar compartment pathway and is degraded. RopGEF1 directly interacts with several clade A PP2C protein phosphatases, including ABI1. Interestingly, RopGEF1 undergoes constitutive degradation in pp2c quadruple abi1/abi2/hab1/pp2ca mutant plants, revealing that active PP2C protein phosphatases protect and stabilize RopGEF1 from ABA-mediated degradation. Interestingly, ABA-mediated degradation of RopGEF1 also plays an important role in ABA-mediated inhibition of lateral root growth. The presented findings point to a PP2C-RopGEF-ROP/RAC control loop model that is proposed to aid in shutting off ABA signal transduction, to counteract leaky ABA signal transduction caused by “monomeric” PYL/RCAR ABA receptors in the absence of stress, and facilitate signaling in response to ABA. PMID:27192441

A local difference in Hedgehog signal transduction increases mechanical cell bond tension and biases cell intercalations along the Drosophila anteroposterior compartment boundary.

PubMed

Rudolf, Katrin; Umetsu, Daiki; Aliee, Maryam; Sui, Liyuan; Jülicher, Frank; Dahmann, Christian

2015-11-15

Tissue organization requires the interplay between biochemical signaling and cellular force generation. The formation of straight boundaries separating cells with different fates into compartments is important for growth and patterning during tissue development. In the developing Drosophila wing disc, maintenance of the straight anteroposterior (AP) compartment boundary involves a local increase in mechanical tension at cell bonds along the boundary. The biochemical signals that regulate mechanical tension along the AP boundary, however, remain unknown. Here, we show that a local difference in Hedgehog signal transduction activity between anterior and posterior cells is necessary and sufficient to increase mechanical tension along the AP boundary. This difference in Hedgehog signal transduction is also required to bias cell rearrangements during cell intercalations to keep the characteristic straight shape of the AP boundary. Moreover, severing cell bonds along the AP boundary does not reduce tension at neighboring bonds, implying that active mechanical tension is upregulated, cell bond by cell bond. Finally, differences in the expression of the homeodomain-containing protein Engrailed also contribute to the straight shape of the AP boundary, independently of Hedgehog signal transduction and without modulating cell bond tension. Our data reveal a novel link between local differences in Hedgehog signal transduction and a local increase in active mechanical tension of cell bonds that biases junctional rearrangements. The large-scale shape of the AP boundary thus emerges from biochemical signals inducing patterns of active tension on cell bonds. © 2015. Published by The Company of Biologists Ltd.

Serotype-dependent transduction efficiencies of recombinant adeno-associated viral vectors in monkey neocortex

PubMed Central

Gerits, Annelies; Vancraeyenest, Pascaline; Vreysen, Samme; Laramée, Marie-Eve; Michiels, Annelies; Gijsbers, Rik; Van den Haute, Chris; Moons, Lieve; Debyser, Zeger; Baekelandt, Veerle; Arckens, Lutgarde; Vanduffel, Wim

2015-01-01

Abstract. Viral vector-mediated expression of genes (e.g., coding for opsins and designer receptors) has grown increasingly popular. Cell-type specific expression is achieved by altering viral vector tropism through crosspackaging or by cell-specific promoters driving gene expression. Detailed information about transduction properties of most recombinant adeno-associated viral vector (rAAV) serotypes in macaque cortex is gradually becoming available. Here, we compare transduction efficiencies and expression patterns of reporter genes in two macaque neocortical areas employing different rAAV serotypes and promoters. A short version of the calmodulin-kinase-II (CaMKIIα0.4) promoter resulted in reporter gene expression in cortical neurons for all tested rAAVs, albeit with different efficiencies for spread: rAAV2/5>>rAAV2/7>rAAV2/8>rAAV2/9>>rAAV2/1 and proportion of transduced cells: rAAV2/1>rAAV2/5>rAAV2/7=rAAV2/9>rAAV2/8. In contrast to rodent studies, the cytomegalovirus (CMV) promoter appeared least efficient in macaque cortex. The human synapsin-1 promoter preceded by the CMV enhancer (enhSyn1) produced homogeneous reporter gene expression across all layers, while two variants of the CaMKIIα promoter resulted in different laminar transduction patterns and cell specificities. Finally, differences in expression patterns were observed when the same viral vector was injected in two neocortical areas. Our results corroborate previous findings that reporter-gene expression patterns and efficiency of rAAV transduction depend on serotype, promoter, cortical layer, and area. PMID:26839901

The role of the inhibitors of interleukin-6 signal transduction SHP2 and SOCS3 for desensitization of interleukin-6 signalling.

PubMed Central

Fischer, Patrick; Lehmann, Ute; Sobota, Radoslaw M; Schmitz, Jochen; Niemand, Claudia; Linnemann, Sonja; Haan, Serge; Behrmann, Iris; Yoshimura, Akihiko; Johnston, James A; Müller-Newen, Gerhard; Heinrich, Peter C; Schaper, Fred

2004-01-01

The immediate early response of cells treated with IL-6 (interleukin-6) is the activation of the signal transducer and activator of transcription (STAT)3. The Src homology domain 2 (SH2)-containing protein tyrosine phosphatase SHP2 and the feedback inhibitor SOCS3 (suppressor of cytokine signalling) are potent inhibitors of IL-6 signal transduction. Impaired function of SOCS3 or SHP2 leads to enhanced and prolonged IL-6 signalling. The inhibitory function of both proteins depends on their recruitment to the tyrosine motif 759 within glycoprotein gp130. In contrast to inactivation, desensitization of signal transduction is regarded as impaired responsiveness due to prestimulation. Usually, after activation the sensing receptor becomes inactivated by modifications such as phosphorylation, internalization or degradation. We designed an experimental approach which allows discrimination between desensitization and inactivation of IL-6 signal transduction. We observed that pre-stimulation with IL-6 renders cells less sensitive to further stimulation with IL-6. After several hours, the cells become sensitive again. We show that not only signal transduction through previously activated receptors is affected by desensitization but signalling through receptors which were not targeted by the first stimulation was also attenuated ( trans -desensitization). Interestingly, in contrast to inhibition, desensitization does not depend on the presence of functional SHP2. Furthermore, cells lacking SOCS3 show constitutive STAT3 activation which is not affected by pre-stimulation with IL-6. All these observations suggest that desensitization and inhibition of signalling are mechanistically distinct. PMID:14611646

Physiological performance of warm-adapted marine ectotherms: Thermal limits of mitochondrial energy transduction efficiency.

PubMed

Martinez, Eloy; Hendricks, Eric; Menze, Michael A; Torres, Joseph J

2016-01-01

Thermal regimes in aquatic systems have profound implications for the physiology of ectotherms. In particular, the effect of elevated temperatures on mitochondrial energy transduction in tropical and subtropical teleosts may have profound consequences on organismal performance and population viability. Upper and lower whole-organism critical temperatures for teleosts suggest that subtropical and tropical species are not susceptible to the warming trends associated with climate change, but sub-lethal effects on energy transduction efficiency and population dynamics remain unclear. The goal of the present study was to compare the thermal sensitivity of processes associated with mitochondrial energy transduction in liver mitochondria from the striped mojarra (Eugerres plumieri), the whitemouth croaker (Micropogonias furnieri) and the palometa (Trachinotus goodei), to those of the subtropical pinfish (Lagodon rhomboides) and the blue runner (Caranx crysos). Mitochondrial function was assayed at temperatures ranging from 10 to 40°C and results obtained for both tropical and subtropical species showed a reduction in the energy transduction efficiency of the oxidative phosphorylation (OXPHOS) system in most species studied at temperatures below whole-organism critical temperature thresholds. Our results show a loss of coupling between O2 consumption and ATP production before the onset of the critical thermal maxima, indicating that elevated temperature may severely impact the yield of ATP production per carbon unit oxidized. As warming trends are projected for tropical regions, increasing water temperatures in tropical estuaries and coral reefs could impact long-term growth and reproductive performance in tropical organisms, which are already close to their upper thermal limit. Copyright © 2015 Elsevier Inc. All rights reserved.

Chemical Modification with High Molecular Weight Polyethylene Glycol Reduces Transduction of Hepatocytes and Increases Efficacy of Intravenously Delivered Oncolytic Adenovirus

PubMed Central

Doronin, Konstantin; Shashkova, Elena V.; May, Shannon M.; Hofherr, Sean E.

2009-01-01

Abstract Oncolytic adenoviruses are anticancer agents that replicate within tumors and spread to uninfected tumor cells, amplifying the anticancer effect of initial transduction. We tested whether coating the viral particle with polyethylene glycol (PEG) could reduce transduction of hepatocytes and hepatotoxicity after systemic (intravenous) administration of oncolytic adenovirus serotype 5 (Ad5). Conjugating Ad5 with high molecular weight 20-kDa PEG but not with 5-kDa PEG reduced hepatocyte transduction and hepatotoxicity after intravenous injection. PEGylation with 20-kDa PEG was as efficient at detargeting adenovirus from Kupffer cells and hepatocytes as virus predosing and warfarin. Bioluminescence imaging of virus distribution in two xenograft tumor models in nude mice demonstrated that PEGylation with 20-kDa PEG reduced liver infection 19- to 90-fold. Tumor transduction levels were similar for vectors PEGylated with 20-kDa PEG and unPEGylated vectors. Anticancer efficacy after a single intravenous injection was retained at the level of unmodified vector in large established prostate carcinoma xenografts, resulting in complete elimination of tumors in all animals and long-term tumor-free survival. Anticancer efficacy after a single intravenous injection was increased in large established hepatocellular carcinoma xenografts, resulting in significant prolongation of survival as compared with unmodified vector. The increase in efficacy was comparable to that obtained with predosing and warfarin pretreatment, significantly extending the median of survival. Shielding adenovirus with 20-kDa PEG may be a useful approach to improve the therapeutic window of oncolytic adenovirus after systemic delivery to primary and metastatic tumor sites. PMID:19469693

The third helix of the murine Hoxc8 homeodomain facilitates protein transduction in mammalian cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kong, Kyoung-Ah; Gadi, Jogeswar; Park, Hyoung Woo

2008-12-05

Previously, we have demonstrated that purified Hoxc8 homeoprotein has the ability to penetrate the cellular membrane and can be transduced efficiently into COS-7 cells. Moreover, the Hoxc8 protein is able to form a complex with DNA molecules in vitro and helps the DNA be delivered intracellularly, serving as a gene delivery vehicle. Here, we further analyzed the membrane transduction activity of Hoxc8 protein and provide the evidence that the 16 amino acid (a.a.191-206, 2.23 kDa) third helix of murine Hoxc8 protein is an efficient protein transduction domain (PTD). When the 16 amino acid peptide was fused at the carboxyl terminalmore » of enhanced green fluorescence protein (EGFP), the fusion proteins were transduced efficiently into the primary pig fetal fibroblast cells. The transduction efficiency increased in a concentration-dependent manner up to 1 {mu}M, and appeared to plateau above a concentration of 1 {mu}M. When tandem multimers of PTD, EGFP-PTD(2), EGFP-PTD(3), EGFP-PTD(4), and EGFP-PTD(5), were analyzed at 500 nM of concentration, the penetrating efficiency increased in a dose-dependent manner. As the number of PTDs increased, the EGFP signal also increased, although the signal maintained plateau after EGFP-PTD(3). These results indicate that the 16 amino acid third helix is the key element responsible for the membrane transduction activity of Hoxc8 proteins, and further suggest that the small peptide could serve as a therapeutic delivery vehicle for large cargo proteins.« less

Evolution from Collaborative Learning to Symbiotic E-Learning: Creation of New E-Learning Environment for Knowledge Society

ERIC Educational Resources Information Center

Songhao, He; Saito, Kenji; Maeda, Takashi; Kubo, Takara

2011-01-01

For people who live in the knowledge society which has rapidly been changing, learning in the widest sense becomes indispensable in all phases of working, living and playing. The construction of an environment, to meet the demands of people who need to acquire new knowledge and skills as the need arises, and enlighten each other regularly, is…

Activity-Based Protein Profiling of Microbes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadler, Natalie C.; Wright, Aaron T.

Activity-Based Protein Profiling (ABPP) in conjunction with multimodal characterization techniques has yielded impactful findings in microbiology, particularly in pathogen, bioenergy, drug discovery, and environmental research. Using small molecule chemical probes that react irreversibly with specific proteins or protein families in complex systems has provided insights in enzyme functions in central metabolic pathways, drug-protein interactions, and regulatory protein redox, for systems ranging from photoautotrophic cyanobacteria to mycobacteria, and combining live cell or cell extract ABPP with proteomics, molecular biology, modeling, and other techniques has greatly expanded our understanding of these systems. New opportunities for application of ABPP to microbial systems include:more » enhancing protein annotation, characterizing protein activities in myriad environments, and reveal signal transduction and regulatory mechanisms in microbial systems.« less

Abscisic Acid Synthesis and Response

PubMed Central

Finkelstein, Ruth

2013-01-01

Abscisic acid (ABA) is one of the “classical” plant hormones, i.e. discovered at least 50 years ago, that regulates many aspects of plant growth and development. This chapter reviews our current understanding of ABA synthesis, metabolism, transport, and signal transduction, emphasizing knowledge gained from studies of Arabidopsis. A combination of genetic, molecular and biochemical studies has identified nearly all of the enzymes involved in ABA metabolism, almost 200 loci regulating ABA response, and thousands of genes regulated by ABA in various contexts. Some of these regulators are implicated in cross-talk with other developmental, environmental or hormonal signals. Specific details of the ABA signaling mechanisms vary among tissues or developmental stages; these are discussed in the context of ABA effects on seed maturation, germination, seedling growth, vegetative stress responses, stomatal regulation, pathogen response, flowering, and senescence. PMID:24273463

Translational neurocardiology: preclinical models and cardioneural integrative aspects.

PubMed

Ardell, J L; Andresen, M C; Armour, J A; Billman, G E; Chen, P-S; Foreman, R D; Herring, N; O'Leary, D S; Sabbah, H N; Schultz, H D; Sunagawa, K; Zucker, I H

2016-07-15

Neuronal elements distributed throughout the cardiac nervous system, from the level of the insular cortex to the intrinsic cardiac nervous system, are in constant communication with one another to ensure that cardiac output matches the dynamic process of regional blood flow demand. Neural elements in their various 'levels' become differentially recruited in the transduction of sensory inputs arising from the heart, major vessels, other visceral organs and somatic structures to optimize neuronal coordination of regional cardiac function. This White Paper will review the relevant aspects of the structural and functional organization for autonomic control of the heart in normal conditions, how these systems remodel/adapt during cardiac disease, and finally how such knowledge can be leveraged in the evolving realm of autonomic regulation therapy for cardiac therapeutics. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

THE RGM/DRAGON FAMILY OF BMP CO-RECEPTORS

PubMed Central

Corradini, Elena; Babitt, Jodie L.; Lin, Herbert Y.

2013-01-01

The BMP signaling pathway controls a number of cell processes during development and in adult tissues. At the cellular level, ligands of the BMP family act by binding a hetero-tetrameric signaling complex, composed of two type I and two type II receptors. BMP ligands make use of a limited number of receptors, which in turn activate a common signal transduction cascade at the intracellular level. A complex regulatory network is required in order to activate the signaling cascade at proper times and locations, and to generate specific downstream effects in the appropriate cellular context. One such regulatory mechanism is the repulsive guidance molecule (RGM) family of BMP co-receptors. This article reviews the current knowledge regarding the structure, regulation, and function of RGMs, focusing on known and potential roles of RGMs in physiology and pathophysiology. PMID:19897400

How to design cell-based biosensors using the sol-gel process.

PubMed

Depagne, Christophe; Roux, Cécile; Coradin, Thibaud

2011-05-01

Inorganic gels formed using the sol-gel process are promising hosts for the encapsulation of living organisms and the design of cell-based biosensors. However, the possibility to use the biological activity of entrapped cells as a biological signal requires a good understanding and careful control of the chemical and physical conditions in which the organisms are placed before, during, and after gel formation, and their impact on cell viability. Moreover, it is important to examine the possible transduction methods that are compatible with sol-gel encapsulated cells. Through an updated presentation of the current knowledge in this field and based on selected examples, this review shows how it has been possible to convert a chemical technology initially developed for the glass industry into a biotechnological tool, with current limitations and promising specificities.

Applications of Aptamers as Sensors

NASA Astrophysics Data System (ADS)

Cho, Eun Jeong; Lee, Joo-Woon; Ellington, Andrew D.

2009-07-01

Aptamers are ligand-binding nucleic acids whose affinities and selectivities can rival those of antibodies. They have been adapted to analytical applications not only as alternatives to antibodies, but as unique reagents in their own right. In particular, aptamers can be readily site-specifically modified during chemical or enzymatic synthesis to incorporate particular reporters, linkers, or other moieties. Also, aptamer secondary structures can be engineered to undergo analyte-dependent conformational changes, which, in concert with the ability to specifically place chemical agents, opens up a wealth of possible signal transduction schemas, irrespective of whether the detection modality is optical, electrochemical, or mass based. Finally, because aptamers are nucleic acids, they are readily adapted to sequence- (and hence signal-) amplification methods. However, application of aptamers without a basic knowledge of their biochemistry or technical requirements can cause serious analytical difficulties.

Age-related changes in the response of intestinal cells to parathyroid hormone.

PubMed

Russo de Boland, Ana

2004-12-01

The concept of the role(s) of parathyroid hormone (PTH), has expanded from that on acting on the classical target tissues, bone and kidney, to the intestine where its actions are of regulatory and developmental importance: regulation of intracellular calcium through modulation of second messengers and, activation of mitogenic cascades leading to cell proliferation. Several causes have been postulated to modify the hormone response in intestinal cells with ageing, among them, alterations of PTH receptor (PTHR1) binding sites, reduced expression of G proteins and hormone signal transduction changes. The current review summarizes the actual knowledge regarding the molecular and biochemical basis of age-impaired PTH receptor-mediated signaling in intestinal cells. A fundamental understanding of why PTH functions are impaired with age will enhance our understanding of its importance in intestinal cell physiology.

Protein arginine methylation/demethylation and cancer

PubMed Central

Poulard, Coralie; Corbo, Laura; Le Romancer, Muriel

2016-01-01

Protein arginine methylation is a common post-translational modification involved in numerous cellular processes including transcription, DNA repair, mRNA splicing and signal transduction. Currently, there are nine known members of the protein arginine methyltransferase (PRMT) family, but only one arginine demethylase has been identified, namely the Jumonji domain-containing 6 (JMJD6). Although its demethylase activity was initially challenged, its dual activity as an arginine demethylase and a lysine hydroxylase is now recognized. Interestingly, a growing number of substrates for arginine methylation and demethylation play key roles in tumorigenesis. Though alterations in the sequence of these enzymes have not been identified in cancer, their overexpression is associated with various cancers, suggesting that they could constitute targets for therapeutic strategies. In this review, we present the recent knowledge of the involvement of PRMTs and JMJD6 in tumorigenesis. PMID:27556302

Knowledge management for systems biology a general and visually driven framework applied to translational medicine.

PubMed

Maier, Dieter; Kalus, Wenzel; Wolff, Martin; Kalko, Susana G; Roca, Josep; Marin de Mas, Igor; Turan, Nil; Cascante, Marta; Falciani, Francesco; Hernandez, Miguel; Villà-Freixa, Jordi; Losko, Sascha

2011-03-05

To enhance our understanding of complex biological systems like diseases we need to put all of the available data into context and use this to detect relations, pattern and rules which allow predictive hypotheses to be defined. Life science has become a data rich science with information about the behaviour of millions of entities like genes, chemical compounds, diseases, cell types and organs, which are organised in many different databases and/or spread throughout the literature. Existing knowledge such as genotype-phenotype relations or signal transduction pathways must be semantically integrated and dynamically organised into structured networks that are connected with clinical and experimental data. Different approaches to this challenge exist but so far none has proven entirely satisfactory. To address this challenge we previously developed a generic knowledge management framework, BioXM™, which allows the dynamic, graphic generation of domain specific knowledge representation models based on specific objects and their relations supporting annotations and ontologies. Here we demonstrate the utility of BioXM for knowledge management in systems biology as part of the EU FP6 BioBridge project on translational approaches to chronic diseases. From clinical and experimental data, text-mining results and public databases we generate a chronic obstructive pulmonary disease (COPD) knowledge base and demonstrate its use by mining specific molecular networks together with integrated clinical and experimental data. We generate the first semantically integrated COPD specific public knowledge base and find that for the integration of clinical and experimental data with pre-existing knowledge the configuration based set-up enabled by BioXM reduced implementation time and effort for the knowledge base compared to similar systems implemented as classical software development projects. The knowledgebase enables the retrieval of sub-networks including protein-protein interaction, pathway, gene--disease and gene--compound data which are used for subsequent data analysis, modelling and simulation. Pre-structured queries and reports enhance usability; establishing their use in everyday clinical settings requires further simplification with a browser based interface which is currently under development.

Knowledge management for systems biology a general and visually driven framework applied to translational medicine

PubMed Central

2011-01-01

Background To enhance our understanding of complex biological systems like diseases we need to put all of the available data into context and use this to detect relations, pattern and rules which allow predictive hypotheses to be defined. Life science has become a data rich science with information about the behaviour of millions of entities like genes, chemical compounds, diseases, cell types and organs, which are organised in many different databases and/or spread throughout the literature. Existing knowledge such as genotype - phenotype relations or signal transduction pathways must be semantically integrated and dynamically organised into structured networks that are connected with clinical and experimental data. Different approaches to this challenge exist but so far none has proven entirely satisfactory. Results To address this challenge we previously developed a generic knowledge management framework, BioXM™, which allows the dynamic, graphic generation of domain specific knowledge representation models based on specific objects and their relations supporting annotations and ontologies. Here we demonstrate the utility of BioXM for knowledge management in systems biology as part of the EU FP6 BioBridge project on translational approaches to chronic diseases. From clinical and experimental data, text-mining results and public databases we generate a chronic obstructive pulmonary disease (COPD) knowledge base and demonstrate its use by mining specific molecular networks together with integrated clinical and experimental data. Conclusions We generate the first semantically integrated COPD specific public knowledge base and find that for the integration of clinical and experimental data with pre-existing knowledge the configuration based set-up enabled by BioXM reduced implementation time and effort for the knowledge base compared to similar systems implemented as classical software development projects. The knowledgebase enables the retrieval of sub-networks including protein-protein interaction, pathway, gene - disease and gene - compound data which are used for subsequent data analysis, modelling and simulation. Pre-structured queries and reports enhance usability; establishing their use in everyday clinical settings requires further simplification with a browser based interface which is currently under development. PMID:21375767

Cochlear Hair Cell Electrochemistry: Mechanisms for Bidirectional Transduction.

DTIC Science & Technology

1988-06-30

cytoplasm in the cell’s laminated cisternal system. More specifically, we postulate that intracochlear potential gradients associated with acoustic...transduction drive intracellular fluids through an electo-osmotic "pump" formed by the plasma membrane and the morphologically unique laminated cisternal ...laminated cisternal system in the hearing loss measured with brainstem evoked response. The highly polycationic nature of the polyamines suggest their

Multiaxis sensing using metal organic frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Talin, Albert Alec; Allendorf, Mark D.; Leonard, Francois

2017-01-17

A sensor device including a sensor substrate; and a thin film comprising a porous metal organic framework (MOF) on the substrate that presents more than one transduction mechanism when exposed to an analyte. A method including exposing a porous metal organic framework (MOF) on a substrate to an analyte; and identifying more than one transduction mechanism in response to the exposure to the analyte.

Adenoviral transduction supports matrix expression of alginate cultured articular chondrocytes.

PubMed

Pohle, D; Kasch, R; Herlyn, P; Bader, R; Mittlmeier, T; Pützer, B M; Müller-Hilke, B

2012-09-01

The present study examines the effects of adenoviral (Ad) transduction of human primary chondrocyte on transgene expression and matrix production. Primary chondrocytes were isolated from healthy articular cartilage and from cartilage with mild osteoarthritis (OA), transduced with an Ad vector and either immediately cultured in alginate or expanded in monolayer before alginate culture. Proteoglycan production was measured using dimethylmethylene blue (DMMB) assay and matrix gene expression was quantified by real-time PCR. Viral infection of primary chondrocytes results in a stable long time transgene expression for up to 13 weeks. Ad transduction does not significantly alter gene expression and matrix production if chondrocytes are immediately embedded in alginate. However, if expanded prior to three dimension (3D) culture in alginate, chondrocytes produce not only more proteoglycans compared to non-transduced controls, but also display an increased anabolic and decreased catabolic activity compared to non-transduced controls. We therefore suggest that successful autologous chondrocyte transplantation (ACT) should combine adenoviral transduction of primary chondrocytes with expansion in monolayer followed by 3D culture. Future studies will be needed to investigate whether the subsequent matrix production can be further improved by using Ad vectors bearing genes encoding matrix proteins. Copyright © 2012 Wiley Periodicals, Inc.

Transcription factor-based modulation of neural stem cell differentiation using direct protein transduction

PubMed Central

Stock, Kristin; Nolden, Lars; Edenhofer, Frank; Quandel, Tamara

2010-01-01

In contrast to conventional gene transfer strategies, the direct introduction of recombinant proteins into cells bypasses the risk of insertional mutagenesis and offers an alternative to genetic intervention. Here, we explore whether protein transduction of the gliogenic transcription factor Nkx2.2 can be used to promote oligodendroglial differentiation of mouse embryonic stem cell (ESC)-derived neural stem cells (NSC). To that end, a recombinant cell-permeant form of Nkx2.2 protein was generated. Exposure of ESC-derived NSC to the recombinant protein and initiation of differentiation resulted in a two-fold increase in the number of oligodendrocytes. Furthermore, Nkx2.2-transduced cells exhibited a more mature oligodendroglial phenotype. Comparative viral gene transfer studies showed that the biological effect of Nkx2.2 protein transduction is comparable to that obtained by lentiviral transduction. The results of this proof-of-concept study depict direct intracellular delivery of transcription factors as alternative modality to control lineage differentiation in NSC cultures without genetic modification. Electronic supplementary material The online version of this article (doi:10.1007/s00018-010-0347-1) contains supplementary material, which is available to authorized users. PMID:20352468

Multiple pathways from three types of sugar receptor sites to metabotropic transduction pathways of the blowfly: study by the whole cell-clamp experiments.

PubMed

Kan, Hideko; Kataoka-Shirasugi, Naoko; Amakawa, Taisaku

2011-09-01

Multiple pathways from three types of multiple receptor sites to three types of metabotropic signal transduction pathways were investigated in the whole cell-clamp experiments using isolated labellar sugar receptor neurons (cells) of the adult blowfly, Phormia regina. First, the concentration-response curves of three types of sweet taste components specialized to multiple receptor sites were obtained: sucrose for the pyranose sites (P-sites), fructose for the furanose sites (F-sites), and l-valine for the alkyl sites (R-sites). Next, the effects of inhibitors such as 2', 5'-dideoxyadenosine on adenylyl cyclase in the cAMP pathway, LY 83583 on guanylyl cyclase in the cGMP pathway, and U-73122 on phospholipase C in the IP₃ pathway were examined. The results showed that all of the inhibitors affected each specific target in the second-messenger transduction pathways. The obtained results verified that the P-site corresponded to the cAMP, the F-site to the cGMP, and the R-site to the IP₃ transduction pathway, and that these three signal pathways did not have crossing points. Copyright © 2011 Elsevier Inc. All rights reserved.

Adeno-associated virus vector-mediated transduction in the cat brain.

PubMed

Vite, Charles H; Passini, Marco A; Haskins, Mark E; Wolfe, John H

2003-10-01

Adeno-associated virus (AAV) vectors are capable of delivering a therapeutic gene to the mouse brain that can result in long-term and widespread protein production. However, the human infant brain is more than 1000 times larger than the mouse brain, which will make the treatment of global neurometabolic disorders in children more difficult. In this study, we evaluated the ability of three AAV serotypes (1,2, and 5) to transduce cells in the cat brain as a model of a large mammalian brain. The human lysosomal enzyme beta-glucuronidase (GUSB) was used as a reporter gene, because it can be distinguished from feline GUSB by heat stability. The vectors were injected into the cerebral cortex, caudate nucleus, thalamus, corona radiata, internal capsule, and centrum semiovale of 8-week-old cats. The brains were evaluated for gene expression using in situ hybridization and enzyme histochemistry 10 weeks after surgery. The AAV2 vector was capable of transducing cells in the gray matter, while the AAV1 vector resulted in greater transduction of the gray matter than AAV2 as well as transduction of the white matter. AAV5 did not result in detectable transduction in the cat brain.

Exploring practical knowledge: a case study of an experienced senior tennis performer.

PubMed

Langley, D J; Knight, S M

1996-12-01

The purpose of the study was to explore sport-related practical knowledge through the perceptions and experiences of a senior adult competitive tennis performer. Practical knowledge was defined as goal oriented, experiential knowledge developed within particular physical activity settings. Data were collected through formal interviews and participant observation and analyzed through narrative inquiry and conventional coding techniques. The data suggest that the tennis environment was perceived in terms of the opportunities afforded by that environment. Specifically, the participant's practical knowledge centered on performance capabilities and strategic planning that revealed opponent limitations. This knowledge appeared to be developed and expressed within the relationships among individual capabilities, the task, and the situated context of game play.

The CWI Pathway: Regulation of the Transcriptional Adaptive Response to Cell Wall Stress in Yeast

PubMed Central

Sanz, Ana Belén; García, Raúl; Rodríguez-Peña, José M.; Arroyo, Javier

2017-01-01

Fungi are surrounded by an essential structure, the cell wall, which not only confers cell shape but also protects cells from environmental stress. As a consequence, yeast cells growing under cell wall damage conditions elicit rescue mechanisms to provide maintenance of cellular integrity and fungal survival. Through transcriptional reprogramming, yeast modulate the expression of genes important for cell wall biogenesis and remodeling, metabolism and energy generation, morphogenesis, signal transduction and stress. The yeast cell wall integrity (CWI) pathway, which is very well conserved in other fungi, is the key pathway for the regulation of this adaptive response. In this review, we summarize the current knowledge of the yeast transcriptional program elicited to counterbalance cell wall stress situations, the role of the CWI pathway in the regulation of this program and the importance of the transcriptional input received by other pathways. Modulation of this adaptive response through the CWI pathway by positive and negative transcriptional feedbacks is also discussed. Since all these regulatory mechanisms are well conserved in pathogenic fungi, improving our knowledge about them will have an impact in the developing of new antifungal therapies. PMID:29371494

The Hedgehog Signal Transduction Network

PubMed Central

Robbins, David J.; Fei, Dennis Liang; Riobo, Natalia A.

2013-01-01

Hedgehog (Hh) proteins regulate the development of a wide range of metazoan embryonic and adult structures, and disruption of Hh signaling pathways results in various human diseases. Here, we provide a comprehensive review of the signaling pathways regulated by Hh, consolidating data from a diverse array of organisms in a variety of scientific disciplines. Similar to the elucidation of many other signaling pathways, our knowledge of Hh signaling developed in a sequential manner centered on its earliest discoveries. Thus, our knowledge of Hh signaling has for the most part focused on elucidating the mechanism by which Hh regulates the Gli family of transcription factors, the so-called “canonical” Hh signaling pathway. However, in the past few years, numerous studies have shown that Hh proteins can also signal through Gli-independent mechanisms collectively referred to as “noncanonical” signaling pathways. Noncanonical Hh signaling is itself subdivided into two distinct signaling modules: (i) those not requiring Smoothened (Smo) and (ii) those downstream of Smo that do not require Gli transcription factors. Thus, Hh signaling is now proposed to occur through a variety of distinct context-dependent signaling modules that have the ability to crosstalk with one another to form an interacting, dynamic Hh signaling network. PMID:23074268

Colored Petri net modeling and simulation of signal transduction pathways.

PubMed

Lee, Dong-Yup; Zimmer, Ralf; Lee, Sang Yup; Park, Sunwon

2006-03-01

Presented herein is a methodology for quantitatively analyzing the complex signaling network by resorting to colored Petri nets (CPN). The mathematical as well as Petri net models for two basic reaction types were established, followed by the extension to a large signal transduction system stimulated by epidermal growth factor (EGF) in an application study. The CPN models based on the Petri net representation and the conservation and kinetic equations were used to examine the dynamic behavior of the EGF signaling pathway. The usefulness of Petri nets is demonstrated for the quantitative analysis of the signal transduction pathway. Moreover, the trade-offs between modeling capability and simulation efficiency of this pathway are explored, suggesting that the Petri net model can be invaluable in the initial stage of building a dynamic model.

Protein Tyrosine Phosphatases: From Housekeeping Enzymes to Master-Regulators of Signal Transduction

PubMed Central

Tonks, Nicholas K.

2013-01-01

There are many misconceptions surrounding the roles of protein phosphatases in the regulation of signal transduction, perhaps the most damaging of which is the erroneous view that these enzymes exert their effects merely as constitutively active housekeeping enzymes. On the contrary, the phosphatases are critical, specific regulators of signaling in their own right and serve an essential function, in a coordinated manner with the kinases, to determine the response to a physiological stimulus. This review is a personal perspective on the development of our understanding of the protein tyrosine phosphatase (PTP) family of enzymes. I have discussed various aspects of the structure, regulation and function of the PTP family, which I hope will illustrate the fundamental importance of these enzymes to the control of signal transduction. PMID:23176256

Optical transduction of E. Coli O157:H7 concentration by using the enhanced Goos-Hänchen shift

NASA Astrophysics Data System (ADS)

Sun, Jingjing; Wang, Xianping; Yin, Cheng; Xiao, Pingping; Li, Honggen; Cao, Zhuangqi

2012-10-01

Within the symmetrical metal-cladding waveguide structure, the optical transduction of the E. coli O157:H7 concentration by using the enhanced Goos-Hänchen (GH) shift is demonstrated to be an advantageous alternative over those evanescent wave-based biosensors. The experimental results indicate that the interaction between the analyte and the excited ultrahigh order modes (in the form of the oscillating wave) is the dominant reason leading to ultrahigh sensitivity. On the condition that the intrinsic damping is well-matched with the radiative damping, the giant GH shift (hundreds of micrometers) offers a higher sensitivity than the regular measurement of reflected light intensity. The transduction limit of E. Coli O157:H7 concentration about 100 cfu ml-1 is achieved.

Characterization of cell surface and extracellular matrix remodeling of Azospirillum brasilense chemotaxis-like 1 signal transduction pathway mutants by atomic force microscopy.

PubMed

Edwards, Amanda Nicole; Siuti, Piro; Bible, Amber N; Alexandre, Gladys; Retterer, Scott T; Doktycz, Mitchel J; Morrell-Falvey, Jennifer L

2011-01-01

To compete in complex microbial communities, bacteria must sense environmental changes and adjust cellular functions for optimal growth. Chemotaxis-like signal transduction pathways are implicated in the regulation of multiple behaviors in response to changes in the environment, including motility patterns, exopolysaccharide production, and cell-to-cell interactions. In Azospirillum brasilense, cell surface properties, including exopolysaccharide production, are thought to play a direct role in promoting flocculation. Recently, the Che1 chemotaxis-like pathway from A. brasilense was shown to modulate flocculation, suggesting an associated modulation of cell surface properties. Using atomic force microscopy, distinct changes in the surface morphology of flocculating A. brasilense Che1 mutant strains were detected. Whereas the wild-type strain produces a smooth mucosal extracellular matrix after 24 h, the flocculating Che1 mutant strains produce distinctive extracellular fibril structures. Further analyses using flocculation inhibition, lectin-binding assays, and comparison of lipopolysaccharides profiles suggest that the extracellular matrix differs between the cheA1 and the cheY1 mutants, despite an apparent similarity in the macroscopic floc structures. Collectively, these data indicate that disruption of the Che1 pathway is correlated with distinctive changes in the extracellular matrix, which likely result from changes in surface polysaccharides structure and/or composition. FEMS Microbiology Letters © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. No claim to original US government works.

A rapid and visual aptasensor for Lipopolysaccharides detection based on the bulb-like triplex turn-on switch coupled with HCR-HRP nanostructures.

PubMed

Xu, Wentao; Tian, Jingjing; Shao, Xiangli; Zhu, Longjiao; Huang, Kunlun; Luo, Yunbo

2017-03-15

For previously reported aptasensor, the sensitivity and selectivity of aptamers to targets were often suppressed due to the reporter label of single-stranded molecular beacon or hindrance of the duplex DNA strand displacement. To solve the affinity declining of aptamers showed in traditional way and realize on-site rapid detection of Lipopolysaccharides (LPS), we developed an ingenious structure-switching aptasensor based on the bulb-like triplex turn-on switch (BTTS) as the effective molecular recognition and signal transduction element and streptavidin-horseradish peroxidase modified hybridization chain reaction (HCR-HRP) nanocomposites as the signal amplifier and signal report element. In the presence of LPS, the bulb-like LPS-aptamer (BLA) and LPS formed the LPS/aptamer complex, while the BTTS disassembled and liberated the dissociative bridge probes (BP) to achieve molecular recognition and signal transduction. Immobilized BP, captured by immobilized capture probes (CP), triggered hybridization chain reactions (HCR) to amplify the switching signal, and the HCR products were then modified with streptavidin-horseradish peroxidase (SA-HRP) to form HCR-HRP nanostructures to output colorimetric signals. In less than four hours, the proposed biosensor showed a detection limit of 50pg/mL of LPS quantitatively with the portable spectrophotometer and the observation limit of 20ng/mL semi-quantitatively with the naked eye, opening up new opportunities for LPS detection in future clinical diagnosis, food security and environment monitoring. Copyright © 2016 Elsevier B.V. All rights reserved.

Vitamin E and mast cells.

PubMed

Zingg, Jean-Marc

2007-01-01

Mast cells play an important role in the immune system by interacting with B and T cells and by releasing several mediators involved in activating other cells. Hyperreactivity of mast cells and their uncontrolled accumulation in tissues lead to increased release of inflammatory mediators contributing to the pathogenesis of several diseases such as rheumatoid arthritis, atherosclerosis, multiple sclerosis, and allergic disorders such as asthma and allergic rhinitis. Interference with mast cell proliferation, survival, degranulation, and migration by synthetic or natural compounds may represent a preventive strategy for the management of these diseases. Natural vitamin E covers a group of eight analogues-the alpha-, beta-, gamma-, and delta-tocopherols and the alpha-, beta-, gamma-, and delta-tocotrienols, but only alpha-tocopherol is efficiently retained by the liver and distributed to peripheral tissues. Mast cells preferentially locate in the proximity of tissues that interface with the external environment (the epithelial surface of the skin, the gastrointestinal mucosa, and the respiratory system), what may render them accessible to treatments with inefficiently retained natural vitamin E analogues and synthetic derivatives. In addition to scavenging free radicals, the natural vitamin E analogues differently modulate signal transduction and gene expression in several cell lines; in mast cells, protein kinase C, protein phosphatase 2A, and protein kinase B are affected by vitamin E, leading to the modulation of proliferation, apoptosis, secretion, and migration. In this chapter, the possibility that vitamin E can prevent diseases with mast cells involvement by modulating signal transduction and gene expression is evaluated.

Signal transduction and oxidative processes in sinonasal polyposis.

PubMed

Cannady, Steven B; Batra, Pete S; Leahy, Rachel; Citardi, Martin J; Janocha, Allison; Ricci, Kristin; Comhair, Suzy A A; Bodine, Melanie; Wang, Zeneng; Hazen, Stanley L; Erzurum, Serpil C

2007-12-01

Nasal polyposis is characterized by impaired regulation of nasal tissue growth and is associated with chronic inflammation, sinus infections, and low levels of nitric oxide (NO). Based on its critical role in mediating cell growth and antimicrobial function, decrease of NO levels has been implicated in the pathogenesis of nasal polyposis. We sought to evaluate mechanisms for the low NO level in polyposis, including factors regulating NO synthase (NOS) expression and activity and NO consumptive processes in nasal epithelial cells and nasal lavage fluid. Eighteen patients with nasal polyposis and 8 healthy control subjects were studied. Nasal brushings, nasal lavage fluid, and nasal biopsy specimens were collected and analyzed. NO metabolite levels (nitrite and nitrate) in nasal lavage fluid from patients with polyps were less than those in control subjects, but activation of signal transduction and inducer of transcription 1, which regulates inducible NOS gene expression and protein expression, was present at higher levels in polyp than in healthy control tissue. Levels of arginine, methylarginine, and endogenous NOS inhibitors were similar between polyp and control tissue. In contrast, superoxide dismutase activity of polyp tissues was lower than that seen in control tissue and associated with increased nitrotyrosine, a biomarker of oxidant consumptive products of NO. Taken together, these data suggest that the nasal polyp environment is characterized by abnormalities in NO metabolism that might predispose to altered regulation of tissue growth and infection. Identification of NO metabolic abnormalities might lead to novel treatments for sinonasal polyposis targeted against the pathways identified within this study.

Emergence, development and diversification of the TGF-beta signalling pathway within the animal kingdom.

PubMed

Huminiecki, Lukasz; Goldovsky, Leon; Freilich, Shiri; Moustakas, Aristidis; Ouzounis, Christos; Heldin, Carl-Henrik

2009-02-03

The question of how genomic processes, such as gene duplication, give rise to co-ordinated organismal properties, such as emergence of new body plans, organs and lifestyles, is of importance in developmental and evolutionary biology. Herein, we focus on the diversification of the transforming growth factor-beta (TGF-beta) pathway -- one of the fundamental and versatile metazoan signal transduction engines. After an investigation of 33 genomes, we show that the emergence of the TGF-beta pathway coincided with appearance of the first known animal species. The primordial pathway repertoire consisted of four Smads and four receptors, similar to those observed in the extant genome of the early diverging tablet animal (Trichoplax adhaerens). We subsequently retrace duplications in ancestral genomes on the lineage leading to humans, as well as lineage-specific duplications, such as those which gave rise to novel Smads and receptors in teleost fishes. We conclude that the diversification of the TGF-beta pathway can be parsimoniously explained according to the 2R model, with additional rounds of duplications in teleost fishes. Finally, we investigate duplications followed by accelerated evolution which gave rise to an atypical TGF-beta pathway in free-living bacterial feeding nematodes of the genus Rhabditis. Our results challenge the view of well-conserved developmental pathways. The TGF-beta signal transduction engine has expanded through gene duplication, continually adopting new functions, as animals grew in anatomical complexity, colonized new environments, and developed an active immune system.

Simulated Microgravity Induced Cytoskeletal Rearrangements are Modulated by Protooncogenes

NASA Technical Reports Server (NTRS)

Melhado, C. D.; Sanford, G. L.; Bosah, F.; Harris-Hooker, S.

1998-01-01

Microgravity is the environment living systems encounter during space flight and gravitational unloading is the effect of this environment on living systems. The cell, being a multiphasic chemical system, is a useful starting point to study the potential impact of gravity unloading on physiological function. In the absence of gravity, sedimentation of organelles including chromosomes, mitochondria, nuclei, the Golgi apparatus, vacuoles, and the endoplasmic reticulum may be affected. Most of these organelles, however, are somewhat held in place by cytoskeleton. Hansen and Igber suggest that intermediate filaments act to stabilize the nuleus against rotational movement, and integrate cell and nuclear structure. The tensegrity theory supports the idea that mechanical or physical forces alters the cytoskeletal structures of a cell resulting in the changes in cell: matrix interactions and receptor-signaling coupling. This type of stress to the cytoskeleton may be largely responsible regulating cell shape, growth, movement and metabolism. Mouse MC3T3 El cells under microgravity exhibited significant cytoskeletal changes and alterations in cell growth. The alterations in cytoskeleton architecture may be due to changes in the expression of actin related proteins or integrins. Philopott and coworkers reported on changes in the distribution of microtubule and cytoskeleton elements in the cells of heart tissue from space flight rats and those centrifuged at 1.7g. Other researchers have showed that microgravity reduced EGF-induced c-fos and c-jun expression compared to 1 g controls. Since c-fos and c-jun are known regulators of cell growth, it is likely that altered signal transduction involving protooncogenes may play a crucial role in the reduced growth and alterations in cytoskeletal arrangements found during space flight. It is clear that a microgravity environment induces a number of changes in cell shape, cell surface molecules, gene expression, and cytoskeletal reorganization. However the underlying mechanism for these cellular changes have not been clearly defined. We examined alterations in endothelial migration, and cytoskeleton architecture (microfilamentous f-actin and vimentin-rich- intermediate filaments) following wounding under simulated microgravity. We also examined the possibility that altered signal transduction pathways, involving protooncogenes, may play a crucial role in microgravity-induced retardation of cell migration and alterations in cytoskeletal organization. We hypothesize that, based on the tensegrity theory, cytoskeletal organization respond to gravitational unloading and through this response, cell behavior, function and gene expression are modified.

Learning to Predict Consequences as a Method of Knowledge Transfer in Reinforcement Learning.

PubMed

Chalmers, Eric; Contreras, Edgar Bermudez; Robertson, Brandon; Luczak, Artur; Gruber, Aaron

2017-04-17

The reinforcement learning (RL) paradigm allows agents to solve tasks through trial-and-error learning. To be capable of efficient, long-term learning, RL agents should be able to apply knowledge gained in the past to new tasks they may encounter in the future. The ability to predict actions' consequences may facilitate such knowledge transfer. We consider here domains where an RL agent has access to two kinds of information: agent-centric information with constant semantics across tasks, and environment-centric information, which is necessary to solve the task, but with semantics that differ between tasks. For example, in robot navigation, environment-centric information may include the robot's geographic location, while agent-centric information may include sensor readings of various nearby obstacles. We propose that these situations provide an opportunity for a very natural style of knowledge transfer, in which the agent learns to predict actions' environmental consequences using agent-centric information. These predictions contain important information about the affordances and dangers present in a novel environment, and can effectively transfer knowledge from agent-centric to environment-centric learning systems. Using several example problems including spatial navigation and network routing, we show that our knowledge transfer approach can allow faster and lower cost learning than existing alternatives.

Radiofrequency-enhanced vascular gene transduction and expression for intravascular MR imaging-guided therapy: feasibility study in pigs.

PubMed

Du, Xiangying; Qiu, Bensheng; Zhan, Xiangcan; Kolmakova, Antonina; Gao, Fabao; Hofmann, Lawrence V; Cheng, Linzhao; Chatterjee, Subroto; Yang, Xiaoming

2005-09-01

To evaluate the feasibility of radiofrequency (RF)-enhanced vascular gene transduction and expression by using a magnetic resonance (MR) imaging-heating guidewire as an intravascular heating vehicle during MR imaging-guided therapy. The institutional committee for animal care and use approved the experimental protocol. The study included in vitro evaluation of the use of RF energy to enhance gene transduction and expression in vascular cells, as well as in vivo validation of the feasibility of intravascular MR imaging-guided RF-enhanced vascular gene transduction and expression in pig arteries. For in vitro experiments, approximately 10(4) vascular smooth muscle cells were seeded in each of four chambers of a cell culture plate. Next, 1 mL of a green fluorescent protein gene (gfp)-bearing lentivirus was added to each chamber. Chamber 4 was heated at approximately 41 degrees C for 15 minutes by using an MR imaging-heating guidewire connected to a custom RF generator. At day 6 after transduction, the four chambers were examined and compared at confocal microscopy to determine the efficiency of gfp transduction and expression. For the in vivo experiments, a lentivirus vector bearing a therapeutic gene, vascular endothelial growth factor 165 (VEGF-165), was transferred by using a gene delivery balloon catheter in 18 femoral-iliac arteries (nine artery pairs) in domestic pigs and Yucatan pigs with atherosclerosis. During gene infusion, one femoral-iliac artery in each pig was heated to approximately 41 degrees C with RF energy transferred via the intravascular MR imaging-heating guidewire, while the contralateral artery was not heated (control condition). At day 6, the 18 arteries were harvested for quantitative Western blot analysis to compare VEGF-165 transduction and expression efficiency between RF-heated and nonheated arterial groups. Confocal microscopy showed gfp expression in chamber 4 that was 293% the level of expression in chamber 1 (49.6% +/- 25.8 vs 16.8% +/- 8.0). Results of Western blot analysis showed VEGF-165 expression for normal arteries in the RF-heated group that was 300% the level of expression in the nonheated group (70.4 arbitrary units [au] +/- 107.1 vs 23.5 au +/- 29.8), and, for atherosclerotic arteries in the RF-heated group, 986% the level in the nonheated group (129.2 au +/- 100.3 vs 13.1 au +/- 4.9). Simultaneous monitoring and enhancement of vascular gene delivery and expression is feasible with the MR imaging-heating guidewire.

Eyes on the prize: reflections on the impact of the evolving digital ecology on the librarian as expert intermediary and knowledge coach, 1969-2009.

PubMed

Homan, J Michael

2010-01-01

The 2009 Janet Doe Lecture reflects on the continuing value and increasing return on investment of librarian-mediated services in the constantly evolving digital ecology and complex knowledge environment of the health sciences. The interrelationship of knowledge, decision making based on knowledge, technology used to access and retrieve knowledge, and the important linkage roles of expert librarian intermediaries is examined. Professional experiences from 1969 to 2009, occurring during a time of unprecedented changes in the digital ecology of librarianship, are the base on which the evolving role and value of librarians as knowledge coaches and expert intermediaries are examined. Librarian-mediated services linking knowledge and critical decision making in health care have become more valuable than ever as technology continues to reshape an increasingly complex knowledge environment.

PLAC1-specific TCR-engineered T cells mediate antigen-specific antitumor effects in breast cancer

PubMed Central

Li, Qiongshu; Liu, Muyun; Wu, Man; Zhou, Xin; Wang, Shaobin; Hu, Yuan; Wang, Youfu; He, Yixin; Zeng, Xiaoping; Chen, Junhui; Liu, Qubo; Xiao, Dong; Hu, Xiang; Liu, Weibin

2018-01-01

Placenta-specific 1 (PLAC1), a novel cancer-testis antigen (CTA), is expressed in a number of different human malignancies. It is frequently produced in breast cancer, serving a function in tumorigenesis. Adoptive immunotherapy using T cell receptor (TCR)-engineered T cells against CTA mediates objective tumor regression; however, to the best of our knowledge, targeting PLAC1 using engineered T cells has not yet been attempted. In the present study, the cDNAs encoding TCRα- and β-chains specific for human leukocyte antigen (HLA)-A*0201-restricted PLAC1 were cloned from a cytotoxic T-lymphocyte, generated by in vitro by the stimulation of CD8+ T cells using autologous HLA-A2+ dendritic cells loaded with a PLAC1-specific peptide (p28-36, VLCSIDWFM). The TCRα/β-chains were linked by a 2A peptide linker (TCRα-Thosea asigna virus-TCRβ), and the constructs were cloned into the lentiviral vector, followed by transduction into human cytotoxic (CD8+) T cells. The efficiency of transduction was up to 25.16%, as detected by PLAC1 multimers. TCR-transduced CD8+ T cells, co-cultured with human non-metastatic breast cancer MCF-7 cells (PLAC1+, HLA-A2+) and triple-negative breast cancer MDAMB-231 cells (PLAC1+, HLA-A2+), produced interferon γ and tumor necrosis factor α, suggesting TCR activation. Furthermore, the PLAC1 TCR-transduced CD8+ T cells efficiently and specifically identified and annihilated the HLA-A2+/PLAC1+ breast cancer cell lines in a lactate dehydrogenase activity assay. Western blot analysis demonstrated that TCR transduction stimulated the production of mitogen-activated protein kinase signaling molecules, extracellular signal-regulated kinases 1/2 and nuclear factor-κB, through phosphoinositide 3-kinase γ-mediated phosphorylation of protein kinase B in CD8+ T cells. Xenograft mouse assays revealed that PLAC1 TCR-transduced CD8+T cells significantly delayed the tumor progression in mice-bearing breast cancer compared with normal saline or negative control-transduced groups. In conclusion, a novel HLA-A2-restricted and PLAC1-specific TCR was identified. The present study demonstrated PLAC1 to be a potential target for breast cancer treatment; and the usage of PLAC1-specific TCR-engineered T cells may be a novel strategy for PLAC1-positive breast cancer treatment. PMID:29556312

Electrokinetic Transduction of Acoustic Waves In Ocean Sediments

DTIC Science & Technology

2002-09-30

acoustic —motion in ocean sediments. The Biot theory of poroelastic media captures much of the sediment physics left out by other models [2]. It fits...in subsurface acoustical imaging, Mine Counter- Measures, and Anti-Submarine Warfare. To obtain essential experimental data to support the modeling ...Electrokinetic Transduction of Acoustic Waves In Ocean Sediments Gareth I. Block Applied Research Laboratories, U.T. Austin P.O. Box 8029

Enhanced radiosensitivity of malignant glioma cells after adenoviral p53 transduction.

PubMed

Broaddus, W C; Liu, Y; Steele, L L; Gillies, G T; Lin, P S; Loudon, W G; Valerie, K; Schmidt-Ullrich, R K; Fillmore, H L

1999-12-01

The goal of this study was to determine whether adenoviral vector-mediated expression of human wildtype p53 can enhance the radiosensitivity of malignant glioma cells that express native wild-type p53. The p53 gene is thought to function abnormally in the majority of malignant gliomas, although it has been demonstrated to be mutated in only approximately 30%. This has led to studies in which adenoviral transduction with wild-type human p53 has been investigated in an attempt to slow tumor cell growth. Recent studies suggest that reconstitution of wild-type p53 can render cells more susceptible to radiation-mediated death, primarily by p53-mediated apoptosis. Rat RT2 glioma cells were analyzed for native p53 status by reverse transcriptase-polymerase chain reaction and sequence analysis and for p53 expression by Western blot analysis. Clonogenic survival and the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling assay were used to characterize RT2 cell radiosensitivity and apoptosis, respectively, with and without prior transduction with p53-containing and control adenoviral vectors. Animal survival length was monitored after intracerebral implantation with transduced and nontransduced RT2 cells, with and without cranial radiation. The RT2 cells were demonstrated to express native rat wild-type p53 and to markedly overexpress human p53 following adenoviral p53 transduction. The combination of p53 transduction followed by radiation resulted in marked decreases in RT2 cell survival and increases in apoptosis at radiation doses from 2 to 6 Gy. Animals receiving cranial radiation after intracerebral implantation with RT2 cells previously transduced with p53 survived significantly longer than control animals (p<0.01). The ability to enhance the radiosensitivity of malignant glioma cells that express wild-type p53 by using adenoviral transduction to induce overexpression of p53 offers hope for this approach as a therapeutic strategy, not only in human gliomas that express mutant p53, but also in those that express wild-type p53.

Impact of the Central Polypurine Tract on the Kinetics of Human Immunodeficiency Virus Type 1 Vector Transduction

PubMed Central

Van Maele, Bénédicte; De Rijck, Jan; De Clercq, Erik; Debyser, Zeger

2003-01-01

Lentiviral vectors derived from human immunodeficiency virus type 1 (HIV-1) show great promise as gene carriers for future gene therapy. Insertion of a fragment containing the central polypurine tract (cPPT) in HIV-1 vector constructs is known to enhance transduction efficiency drastically, reportedly by facilitating the nuclear import of HIV-1 cDNA through a central DNA flap. We have studied the impact of the cPPT on the kinetics of HIV-1 vector transduction by real-time PCR. The kinetics of total HIV-1 DNA, two-long-terminal-repeat (2-LTR) circles, and, by an Alu-PCR, integrated proviral DNA were monitored. About 6 to 12 h after transduction, the total HIV-1 DNA reached a maximum level, followed by a steep decrease. The 2-LTR circles peaked after 24 to 48 h and were diluted upon cell division. Integration of HIV-1 DNA was first detected at 12 h postinfection. When HIV-1 vectors that contained the cPPT were used, DNA synthesis was similar but a threefold higher amount of 2-LTR circles was detected, confirming the impact on nuclear import. Moreover, a 10-fold increase in the amount of integrated DNA was observed in the presence of the cPPT. Only in the absence of the cPPT was a saturation in 2-LTR circle formation seen at a high multiplicity of infection, suggesting a role for the cPPT in overcoming a barrier to the nuclear import of HIV-1 DNA. A major effect of the central DNA flap on the juxtaposition of both LTRs is unlikely, since transduction with HIV-1 vectors containing ectopic cPPT fragments resulted in increased amounts of 2-LTR circles as well as integrated DNA. Inhibitors of transduction by cPPT-containing HIV vectors were also studied by real-time PCR. The reverse transcriptase inhibitor azidothymidine (AZT) and the nonnucleoside reverse transcriptase inhibitor α-APA clearly inhibited viral DNA synthesis, whereas integrase inhibitors such as the diketo acid L-708,906 and the pyranodipyrimidine V-165 specifically inhibited integration. PMID:12663775

Ultrasound enhances retrovirus-mediated gene transfer.

PubMed

Naka, Toshio; Sakoda, Tsuyoshi; Doi, Takashi; Tsujino, Takeshi; Masuyama, Tohru; Kawashima, Seinosuke; Iwasaki, Tadaaki; Ohyanagi, Mitsumasa

2007-01-01

Viral vector systems are efficient for transfection of foreign genes into many tissues. Especially, retrovirus based vectors integrate the transgene into the genome of the target cells, which can sustain long term expression. However, it has been demonstrated that the transduction efficiency using retrovirus is relatively lower than those of other viruses. Ultrasound was recently reported to increase gene expression using plasmid DNA, with or without, a delivery vehicle. However, there are no reports, which show an ultrasound effect to retrovirus-mediated gene transfer efficiency. Retrovirus-mediated gene transfer systems were used for transfection of 293T cells, bovine aortic endothelial cells (BAECs), rat aortic smooth muscle cells (RASMCs), and rat skeletal muscle myoblasts (L6 cells) with beta-galactosidase (beta-Gal) genes. Transduction efficiency and cell viability assay were performed on 293T cells that were exposed to varying durations (5 to 30 seconds) and power levels (1.0 watts/cm(2) to 4.0 watts/cm(2)) of ultrasound after being transduced by a retrovirus. Effects of ultrasound to the retrovirus itself was evaluated by transduction efficiency of 293T cells. After exposure to varying power levels of ultrasound to a retrovirus for 5 seconds, 293T cells were transduced by a retrovirus, and transduction efficiency was evaluated. Below 1.0 watts/cm(2) and 5 seconds exposure, ultrasound showed increased transduction efficiency and no cytotoxicity to 293T cells transduced by a retrovirus. Also, ultrasound showed no toxicity to the virus itself at the same condition. Exposure of 5 seconds at the power of 1.0 watts/cm(2) of an ultrasound resulted in significant increases in retrovirus-mediated gene expression in all four cell types tested in this experiment. Transduction efficiencies by ultrasound were enhanced 6.6-fold, 4.8-fold, 2.3-fold, and 3.2-fold in 293T cells, BAECs, RASMCs, and L6 cells, respectively. Furthermore, beta-Gal activities were also increased by the retrovirus with ultrasound exposure in these cells. Adjunctive ultrasound exposure was associated with enhanced retrovirus-mediated transgene expression in vitro. Ultrasound associated local gene therapy has potential for not only plasmid-DNA-, but also retrovirus-mediated gene transfer.

Cilia- and Flagella-Associated Protein 69 Regulates Olfactory Transduction Kinetics in Mice

PubMed Central

Dong, Frederick N.

2017-01-01

Animals detect odorous chemicals through specialized olfactory sensory neurons (OSNs) that transduce odorants into neural electrical signals. We identified a novel and evolutionarily conserved protein, cilia- and flagella-associated protein 69 (CFAP69), in mice that regulates olfactory transduction kinetics. In the olfactory epithelium, CFAP69 is enriched in OSN cilia, where olfactory transduction occurs. Bioinformatic analysis suggests that a large portion of CFAP69 can form Armadillo-type α-helical repeats, which may mediate protein–protein interactions. OSNs lacking CFAP69, remarkably, displayed faster kinetics in both the on and off phases of electrophysiological responses at both the neuronal ensemble level as observed by electroolfactogram and the single-cell level as observed by single-cell suction pipette recordings. In single-cell analysis, OSNs lacking CFAP69 showed faster response integration and were able to fire APs more faithfully to repeated odor stimuli. Furthermore, both male and female mutant mice that specifically lack CFAP69 in OSNs exhibited attenuated performance in a buried food pellet test when a background of the same odor to the food pellet was present even though they should have better temporal resolution of coding olfactory stimulation at the peripheral. Therefore, the role of CFAP69 in the olfactory system seems to be to allow the olfactory transduction machinery to work at a precisely regulated range of response kinetics for robust olfactory behavior. SIGNIFICANCE STATEMENT Sensory receptor cells are generally thought to evolve to respond to sensory cues as fast as they can. This idea is consistent with mutational analyses in various sensory systems, where mutations of sensory receptor cells often resulted in reduced response size and slowed response kinetics. Contrary to this idea, we have found that there is a kinetic “damper” present in the olfactory transduction cascade of the mouse that slows down the response kinetics and, by doing so, it reduces the peripheral temporal resolution in coding odor stimuli and allows for robust olfactory behavior. This study should trigger a rethinking of the significance of the intrinsic speed of sensory transduction and the pattern of the peripheral coding of sensory stimuli. PMID:28495971

Elementary signaling modes predict the essentiality of signal transduction network components

PubMed Central

2011-01-01

Background Understanding how signals propagate through signaling pathways and networks is a central goal in systems biology. Quantitative dynamic models help to achieve this understanding, but are difficult to construct and validate because of the scarcity of known mechanistic details and kinetic parameters. Structural and qualitative analysis is emerging as a feasible and useful alternative for interpreting signal transduction. Results In this work, we present an integrative computational method for evaluating the essentiality of components in signaling networks. This approach expands an existing signaling network to a richer representation that incorporates the positive or negative nature of interactions and the synergistic behaviors among multiple components. Our method simulates both knockout and constitutive activation of components as node disruptions, and takes into account the possible cascading effects of a node's disruption. We introduce the concept of elementary signaling mode (ESM), as the minimal set of nodes that can perform signal transduction independently. Our method ranks the importance of signaling components by the effects of their perturbation on the ESMs of the network. Validation on several signaling networks describing the immune response of mammals to bacteria, guard cell abscisic acid signaling in plants, and T cell receptor signaling shows that this method can effectively uncover the essentiality of components mediating a signal transduction process and results in strong agreement with the results of Boolean (logical) dynamic models and experimental observations. Conclusions This integrative method is an efficient procedure for exploratory analysis of large signaling and regulatory networks where dynamic modeling or experimental tests are impractical. Its results serve as testable predictions, provide insights into signal transduction and regulatory mechanisms and can guide targeted computational or experimental follow-up studies. The source codes for the algorithms developed in this study can be found at http://www.phys.psu.edu/~ralbert/ESM. PMID:21426566

Mitochondria-derived hydrogen peroxide selectively enhances T cell receptor-initiated signal transduction.

PubMed

Gill, Tejpal; Levine, Alan D

2013-09-06

T cell receptor (TCR)-initiated signal transduction is reported to increase production of intracellular reactive oxygen species, such as superoxide (O2˙(-)) and hydrogen peroxide (H2O2), as second messengers. Although H2O2 can modulate signal transduction by inactivating protein phosphatases, the mechanism and the subcellular localization of intracellular H2O2 as a second messenger of the TCR are not known. The antioxidant enzyme superoxide dismutase (SOD) catalyzes the dismutation of highly reactive O2˙(-) into H2O2 and thus acts as an intracellular generator of H2O2. As charged O2˙(-) is unable to diffuse through intracellular membranes, cells express distinct SOD isoforms in the cytosol (Cu,Zn-SOD) and mitochondria (Mn-SOD), where they locally scavenge O2˙(-) leading to production of H2O2. A 2-fold organelle-specific overexpression of either SOD in Jurkat T cell lines increases intracellular production of H2O2 but does not alter the levels of intracellular H2O2 scavenging enzymes such as catalase, membrane-bound peroxiredoxin1 (Prx1), and cytosolic Prx2. We report that overexpression of Mn-SOD enhances tyrosine phosphorylation of TCR-associated membrane proximal signal transduction molecules Lck, LAT, ZAP70, PLCγ1, and SLP76 within 1 min of TCR cross-linking. This increase in mitochondrial H2O2 specifically modulates MAPK signaling through the JNK/cJun pathway, whereas overexpressing Cu,Zn-SOD had no effect on any of these TCR-mediated signaling molecules. As mitochondria translocate to the immunological synapse during TCR activation, we hypothesize this translocation provides the effective concentration of H2O2 required to selectively modulate downstream signal transduction pathways.

Efficient biotechnological approach for lentiviral transduction of induced pluripotent stem cells.

PubMed

Zare, Mehrak; Soleimani, Masoud; Mohammadian, Mozhdeh; Akbarzadeh, Abolfazl; Havasi, Parvaneh; Zarghami, Nosratollah

2016-01-01

Induced pluripotent stem (iPS) cells are generated from differentiated adult somatic cells by reprogramming them. Unlimited self-renewal, and the potential to differentiate into any cell type, make iPS cells very promising candidates for basic and clinical research. Furthermore, iPS cells can be genetically manipulated for use as therapeutic tools. DNA can be introduced into iPS cells, using lentiviral vectors, which represent a helpful choice for efficient transduction and stable integration of transgenes. In this study, we compare two methods of lentiviral transduction of iPS cells, namely, the suspension method and the hanging drop method. In contrast to the conventional suspension method, in the hanging drop method, embryoid body (EB) formation and transduction occur concurrently. The iPS cells were cultured to form EBs, and then transduced with lentiviruses, using the conventional suspension method and the hanging drop method, to express miR-128 and green fluorescent protein (GFP). The number of transduced cells were assessed by fluorescent microscopy and flow cytometry. MTT assay and real-time PCR were performed to determine the cell viability and transgene expression, respectively. Morphologically, GFP+ cells were more detectable in the hanging drop method, and this finding was quantified by flow cytometric analysis. According to the results of the MTT assay, cell viability was considerably higher in the hanging drop method, and real-time PCR represented a higher relative expression of miR-128 in the iPS cells introduced with lentiviruses in drops. Altogether, it seems that lentiviral transduction of challenging iPS cells using the hanging drop method offers a suitable and sufficient strategy in their gene transfer, with less toxicity than the conventional suspension method.

Adeno-Associated Virus Vectors and Stem Cells: Friends or Foes?

PubMed

Brown, Nolan; Song, Liujiang; Kollu, Nageswara R; Hirsch, Matthew L

2017-06-01

The infusion of healthy stem cells into a patient-termed "stem-cell therapy"-has shown great promise for the treatment of genetic and non-genetic diseases, including mucopolysaccharidosis type 1, Parkinson's disease, multiple sclerosis, numerous immunodeficiency disorders, and aplastic anemia. Stem cells for cell therapy can be collected from the patient (autologous) or collected from another "healthy" individual (allogeneic). The use of allogenic stem cells is accompanied with the potentially fatal risk that the transplanted donor T cells will reject the patient's cells-a process termed "graft-versus-host disease." Therefore, the use of autologous stem cells is preferred, at least from the immunological perspective. However, an obvious drawback is that inherently as "self," they contain the disease mutation. As such, autologous cells for use in cell therapies often require genetic "correction" (i.e., gene addition or editing) prior to cell infusion and therefore the requirement for some form of nucleic acid delivery, which sets the stage for the AAV controversy discussed herein. Despite being the most clinically applied gene delivery context to date, unlike other more concerning integrating and non-integrating vectors such as retroviruses and adenovirus, those based on adeno-associated virus (AAV) have not been employed in the clinic. Furthermore, published data regarding AAV vector transduction of stem cells are inconsistent in regards to vector transduction efficiency, while the pendulum swings far in the other direction with demonstrations of AAV vector-induced toxicity in undifferentiated cells. The variation present in the literature examining the transduction efficiency of AAV vectors in stem cells may be due to numerous factors, including inconsistencies in stem-cell collection, cell culture, vector preparation, and/or transduction conditions. This review summarizes the controversy surrounding AAV vector transduction of stem cells, hopefully setting the stage for future elucidation and eventual therapeutic applications.

Adeno-associated virus (AAV)-3-based vectors transduce haematopoietic cells not susceptible to transduction with AAV-2-based vectors.

PubMed

Handa, A; Muramatsu, S; Qiu, J; Mizukami, H; Brown, K E

2000-08-01

Although adeno-associated virus (AAV)-2 has a broad tissue-host range and can transduce a wide variety of tissue types, some cells, such as erythro-megakaryoblastoid cells, are non-permissive and appear to lack the AAV-2 receptor. However, limited studies have been reported with the related dependovirus AAV-3. We have previously cloned this virus, characterized its genome and produced an infectious clone. In this study, the gene for green fluorescent protein (GFP) was inserted into AAV-2- and AAV-3-based plasmids and recombinant viruses were produced. These viruses were then used to transduce haematopoietic cells and the transduction efficiencies were compared. In contrast to recombinant (r) AAV-2, rAAV-3 successfully transduced erythroid and megakaryoblastoid cells, although rAAV-2 was superior in transduction of lymphocyte-derived cell lines. Recently, it was reported that heparan sulphate can act as a receptor of AAV-2. The infectivity of rAAV-2 and rAAV-3 was tested with mutant cell lines of Chinese hamster ovary cells that were defective for heparin or heparan sulphate expression on the cell surface. There was no correlation between the ability of rAAV-2 or rAAV-3 to infect cells and the cell surface expression of heparan sulphate and, although heparin blocked both rAAV-2 and rAAV-3 transduction, the ID(50) of rAAV-3 was higher than that of rAAV-2. In addition, virus-binding overlay assays indicated that AAV-2 and AAV-3 bound different membrane proteins. These results suggest not only that there are different cellular receptors for AAV-2 and AAV-3, but that rAAV-3 vectors may be preferred for transduction of some haematopoietic cell types.

Modeling Dynamics of Cell-to-Cell Variability in TRAIL-Induced Apoptosis Explains Fractional Killing and Predicts Reversible Resistance

PubMed Central

Bertaux, François; Stoma, Szymon; Drasdo, Dirk; Batt, Gregory

2014-01-01

Isogenic cells sensing identical external signals can take markedly different decisions. Such decisions often correlate with pre-existing cell-to-cell differences in protein levels. When not neglected in signal transduction models, these differences are accounted for in a static manner, by assuming randomly distributed initial protein levels. However, this approach ignores the a priori non-trivial interplay between signal transduction and the source of this cell-to-cell variability: temporal fluctuations of protein levels in individual cells, driven by noisy synthesis and degradation. Thus, modeling protein fluctuations, rather than their consequences on the initial population heterogeneity, would set the quantitative analysis of signal transduction on firmer grounds. Adopting this dynamical view on cell-to-cell differences amounts to recast extrinsic variability into intrinsic noise. Here, we propose a generic approach to merge, in a systematic and principled manner, signal transduction models with stochastic protein turnover models. When applied to an established kinetic model of TRAIL-induced apoptosis, our approach markedly increased model prediction capabilities. One obtains a mechanistic explanation of yet-unexplained observations on fractional killing and non-trivial robust predictions of the temporal evolution of cell resistance to TRAIL in HeLa cells. Our results provide an alternative explanation to survival via induction of survival pathways since no TRAIL-induced regulations are needed and suggest that short-lived anti-apoptotic protein Mcl1 exhibit large and rare fluctuations. More generally, our results highlight the importance of accounting for stochastic protein turnover to quantitatively understand signal transduction over extended durations, and imply that fluctuations of short-lived proteins deserve particular attention. PMID:25340343

Interferon-α Silencing by Small Interference RNA Increases Adenovirus Transduction and Transgene Expression in Huh7 Cells.

PubMed

Sobrevilla-Navarro, Ana Alondra; Sandoval-Rodríguez, Ana; García-Bañuelos, Jesús Javier; Armendariz-Borunda, Juan; Salazar-Montes, Adriana María

2018-04-01

Adenoviruses are the most common vectors used in clinical trials of gene therapy. In 2017, 21.2% of clinical trials used rAds as vectors. Systemic administration of rAds results in high tropism in the liver. Interferon types α and β are the major antiviral cytokines which orchestrate the host's immune response against rAd, limiting therapeutic gene expression and preventing subsequent vector administration. siRNA is small double-strand RNAs that temporally inhibit the expression of a specific gene. The aim is to evaluate the effect of IFN-α blocking by a specific siRNA on Ad-GFP transduction and on transgene expression in Huh7 cells in culture. Huh7 cells were cultured in DMEM and transfected with 70 nM of siRNA-IFN-α. Six hours later, the cells were exposed to 1 × 10 9  vp/ml of rAd-GFP for 24 h. Expression of IFN-α, TNF-α and the PKR gene was determined by RT-qPCR. Percentage of transduction was analyzed by flow cytometry and by qPCR. GFP expression was determined by western blot. 70 nM of siRNA-IFN-α inhibited 96% of IFN-α and 65% of TNF-α gene expression compared to an irrelevant siRNA. Percentage of transduction and transgene expression increased in these cells compared to an irrelevant siRNA. Inhibition of IFN-α expression by siRNA-IFN-α enabled a higher level of transduction and transgene expression GFP, highlighting the role of IFN-α in the elimination of adenovirus in transduced cells and thus suggesting that its inhibition could be an important strategy for gene therapy in clinical trials using adenovirus as a vector directed to liver diseases.

Intravenous administration of the adeno-associated virus-PHP.B capsid fails to upregulate transduction efficiency in the marmoset brain.

PubMed

Matsuzaki, Yasunori; Konno, Ayumu; Mochizuki, Ryuta; Shinohara, Yoichiro; Nitta, Keisuke; Okada, Yukihiro; Hirai, Hirokazu

2018-02-05

Intravenous administration of adeno-associated virus (AAV)-PHP.B, a capsid variant of AAV9 containing seven amino acid insertions, results in a greater permeability of the blood brain barrier (BBB) than standard AAV9 in mice, leading to highly efficient and global transduction of the central nervous system (CNS). The present study aimed to examine whether the enhanced BBB penetrance of AAV-PHP.B observed in mice also occurs in non-human primates. Thus, a young adult (age, 1.6 years) and an old adult (age, 7.2 years) marmoset received an intravenous injection of AAV-PHP.B expressing enhanced green fluorescent protein (EGFP) under the control of the constitutive CBh promoter (a hybrid of cytomegalovirus early enhancer and chicken β-actin promoter). Age-matched control marmosets were treated with standard AAV9-capsid vectors. The animals were sacrificed 6 weeks after the viral injection. Based on the results, only limited transduction of neurons (0-2%) and astrocytes (0.1-2.5%) was observed in both AAV-PHP.B- and AAV9-treated marmosets. One noticeable difference between AAV-PHP.B and AAV9 was the marked transduction of the peripheral dorsal root ganglia neurons. Indeed, the soma and axons in the projection from the spinal cord to the nucleus cuneatus in the medulla oblongata were strongly labeled with EGFP by AAV-PHP.B. Thus, except for the peripheral dorsal root ganglia neurons, the AAV-PHP.B transduction efficiency in the CNS of marmosets was comparable to that of AAV9 vectors. Copyright © 2017 Elsevier B.V. All rights reserved.

Automated manufacturing of chimeric antigen receptor T cells for adoptive immunotherapy using CliniMACS prodigy.

PubMed

Mock, Ulrike; Nickolay, Lauren; Philip, Brian; Cheung, Gordon Weng-Kit; Zhan, Hong; Johnston, Ian C D; Kaiser, Andrew D; Peggs, Karl; Pule, Martin; Thrasher, Adrian J; Qasim, Waseem

2016-08-01

Novel cell therapies derived from human T lymphocytes are exhibiting enormous potential in early-phase clinical trials in patients with hematologic malignancies. Ex vivo modification of T cells is currently limited to a small number of centers with the required infrastructure and expertise. The process requires isolation, activation, transduction, expansion and cryopreservation steps. To simplify procedures and widen applicability for clinical therapies, automation of these procedures is being developed. The CliniMACS Prodigy (Miltenyi Biotec) has recently been adapted for lentiviral transduction of T cells and here we analyse the feasibility of a clinically compliant T-cell engineering process for the manufacture of T cells encoding chimeric antigen receptors (CAR) for CD19 (CAR19), a widely targeted antigen in B-cell malignancies. Using a closed, single-use tubing set we processed mononuclear cells from fresh or frozen leukapheresis harvests collected from healthy volunteer donors. Cells were phenotyped and subjected to automated processing and activation using TransAct, a polymeric nanomatrix activation reagent incorporating CD3/CD28-specific antibodies. Cells were then transduced and expanded in the CentriCult-Unit of the tubing set, under stabilized culture conditions with automated feeding and media exchange. The process was continuously monitored to determine kinetics of expansion, transduction efficiency and phenotype of the engineered cells in comparison with small-scale transductions run in parallel. We found that transduction efficiencies, phenotype and function of CAR19 T cells were comparable with existing procedures and overall T-cell yields sufficient for anticipated therapeutic dosing. The automation of closed-system T-cell engineering should improve dissemination of emerging immunotherapies and greatly widen applicability. Copyright © 2016. Published by Elsevier Inc.

Benefits of gene transduction of granulocyte macrophage colony-stimulating factor in cancer vaccine using genetically modified dendritic cells.

PubMed

Ojima, Toshiyasu; Iwahashi, Makoto; Nakamura, Masaki; Matsuda, Kenji; Nakamori, Mikihito; Ueda, Kentaro; Naka, Teiji; Katsuda, Masahiro; Miyazawa, Motoki; Yamaue, Hiroki

2007-10-01

Granulocyte macrophage colony-stimulating factor (GM-CSF) is a key cytokine for the generation and stimulation of dendritic cells (DCs), and it may also play a pivotal role in promoting the survival of DCs. In this study, the feasibility of creating a cancer vaccine using DCs adenovirally transduced with the carcinoembryonic antigen (CEA) gene and the GM-CSF gene was examined. In addition, the effect of the co-transduction of GM-CSF gene on the lifespan of these genetically modified DCs was determined. A cytotoxic assay using peripheral blood mononuclear cell (PBMC)-derived cytotoxic T lymphocytes (CTLs) was performed in a 4-h 51Cr release assay. The apoptosis of DCs was examined by TdT-mediated dUTP-FITC nick end labeling (TUNEL) assay. CEA-specific CTLs were generated from PBMCs stimulated with genetically modified DCs expressing CEA. The cytotoxicity of these CTLs was augmented by co-transduction of DCs with the GM-CSF gene. Co-transduction of the GM-CSF gene into DCs inhibited apoptosis of these DCs themselves via up-regulation of Bcl-x(L) expression, leading to the extension of the lifespan of these DCs. Furthermore, the transduction of the GM-CSF gene into DCs also suppressed the incidence of apoptosis of DCs induced by transforming growth factor-beta1 (TGFbeta-1). Immunotherapy using these genetically modified DCs may therefore be useful with several advantages as follows: i) adenoviral toxicity to DCs can be reduced; ii) the lifespan of vaccinated DCs can be prolonged; and iii) GM-CSF may protect DCs from apoptosis induced by tumor-derived TGFbeta-1 in the regional lymph nodes.

Cryptochromes and Hormone Signal Transduction under Near-Zero Magnetic Fields: New Clues to Magnetic Field Effects in a Rice Planthopper.

PubMed

Wan, Gui-Jun; Wang, Wen-Jing; Xu, Jing-Jing; Yang, Quan-Feng; Dai, Ming-Jiang; Zhang, Feng-Jiao; Sword, Gregory A; Pan, Wei-Dong; Chen, Fa-Jun

2015-01-01

Although there are considerable reports of magnetic field effects (MFE) on organisms, very little is known so far about the MFE-related signal transduction pathways. Here we establish a manipulative near-zero magnetic field (NZMF) to investigate the potential signal transduction pathways involved in MFE. We show that exposure of migratory white-backed planthopper, Sogatella furcifera, to the NZMF results in delayed egg and nymphal development, increased frequency of brachypterous females, and reduced longevity of macropterous female adults. To understand the changes in gene expression underlying these phenotypes, we examined the temporal patterns of gene expression of (i) CRY1 and CRY2 as putative magnetosensors, (ii) JHAMT, FAMeT and JHEH in the juvenile hormone pathway, (iii) CYP307A1 in the ecdysone pathway, and (iv) reproduction-related Vitellogenin (Vg). The significantly altered gene expression of CRY1 and CRY2 under the NZMF suggest their developmental stage-specific patterns and potential upstream location in magnetic response. Gene expression patterns of JHAMT, JHEH and CYP307A1 were consistent with the NZMF-triggered delay in nymphal development, higher proportion of brachypterous female adults, and the shortened longevity of macropterous female adults, which show feasible links between hormone signal transduction and phenotypic MFE. By conducting manipulative NZMF experiments, our study suggests an important role of the geomagnetic field (GMF) in modulating development and physiology of insects, provides new insights into the complexity of MFE-magnetosensitivity interactions, and represents an initial but crucial step forward in understanding the molecular basis of cryptochromes and hormone signal transduction involved in MFE.

Simulation based virtual learning environment in medical genetics counseling: an example of bridging the gap between theory and practice in medical education.

PubMed

Makransky, Guido; Bonde, Mads T; Wulff, Julie S G; Wandall, Jakob; Hood, Michelle; Creed, Peter A; Bache, Iben; Silahtaroglu, Asli; Nørremølle, Anne

2016-03-25

Simulation based learning environments are designed to improve the quality of medical education by allowing students to interact with patients, diagnostic laboratory procedures, and patient data in a virtual environment. However, few studies have evaluated whether simulation based learning environments increase students' knowledge, intrinsic motivation, and self-efficacy, and help them generalize from laboratory analyses to clinical practice and health decision-making. An entire class of 300 University of Copenhagen first-year undergraduate students, most with a major in medicine, received a 2-h training session in a simulation based learning environment. The main outcomes were pre- to post- changes in knowledge, intrinsic motivation, and self-efficacy, together with post-intervention evaluation of the effect of the simulation on student understanding of everyday clinical practice were demonstrated. Knowledge (Cohen's d = 0.73), intrinsic motivation (d = 0.24), and self-efficacy (d = 0.46) significantly increased from the pre- to post-test. Low knowledge students showed the greatest increases in knowledge (d = 3.35) and self-efficacy (d = 0.61), but a non-significant increase in intrinsic motivation (d = 0.22). The medium and high knowledge students showed significant increases in knowledge (d = 1.45 and 0.36, respectively), motivation (d = 0.22 and 0.31), and self-efficacy (d = 0.36 and 0.52, respectively). Additionally, 90 % of students reported a greater understanding of medical genetics, 82 % thought that medical genetics was more interesting, 93 % indicated that they were more interested and motivated, and had gained confidence by having experienced working on a case story that resembled the real working situation of a doctor, and 78 % indicated that they would feel more confident counseling a patient after the simulation. The simulation based learning environment increased students' learning, intrinsic motivation, and self-efficacy (although the strength of these effects differed depending on their pre-test knowledge), and increased the perceived relevance of medical educational activities. The results suggest that simulations can help future generations of doctors transfer new understanding of disease mechanisms gained in virtual laboratory settings into everyday clinical practice.

Effects of environment and education on knowledge and attitude of nursing students towards leprosy.

PubMed

Rajkumar, E; Julious, S; Salome, A; Jennifer, G; John, A S; Kannan, L; Richard, J

2011-01-01

The objective of this cross-sectional comparative study was to find the effects of environment and education on knowledge and attitude of nursing students towards leprosy. Data were collected, using a pretested questionnaire, from the first year and third year students of a School of Nursing attached to a leprosy specialty hospital and also from a comparable School of Nursing attached to a general hospital. The results showed that trainees acquired more knowledge on leprosy during training in both schools of nursing. However, those trained in leprosy hospital environment had higher knowledge and attitude scores than those trained in general hospital environment. The attitude of the trainees attached to leprosy hospital was favourable even before they had formal training in leprosy. Those trained in the general hospital showed more favourable attitude after training compared to before training. School of Nursing attached to leprosy hospital provided an atmosphere conducive to learning and understanding more about leprosy. The trainees retained what was learnt because of regular association with patients affected by leprosy. For employment in hospital or community based services or research related to leprosy, nurses trained in a leprosy hospital would have added value of knowledge and attitude.

Supporting Awareness for Augmenting Participation in Collaborative Learning.

ERIC Educational Resources Information Center

Ogata, Hiroaki; Yano, Yoneo

This paper describes Coconuts (Concurrent Collaborative Learning Environment Supported by Awareness), a proposed module of Sharlok (Sharing, Linking and Looking-for Knowledge), an open-ended and collaborative learning environment that integrates a knowledge building tool with a collaborative interface tool. Coconuts was developed in order to…

40 CFR 22.15 - Answer to the complaint.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Answer to the complaint. 22.15 Section 22.15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL CONSOLIDATED RULES OF... respondent has any knowledge. Where respondent has no knowledge of a particular factual allegation and so...

Heat-Responsive Photosynthetic and Signaling Pathways in Plants: Insight from Proteomics.

PubMed

Wang, Xiaoli; Xu, Chenxi; Cai, Xiaofeng; Wang, Quanhua; Dai, Shaojun

2017-10-20

Heat stress is a major abiotic stress posing a serious threat to plants. Heat-responsive mechanisms in plants are complicated and fine-tuned. Heat signaling transduction and photosynthesis are highly sensitive. Therefore, a thorough understanding of the molecular mechanism in heat stressed-signaling transduction and photosynthesis is necessary to protect crop yield. Current high-throughput proteomics investigations provide more useful information for underlying heat-responsive signaling pathways and photosynthesis modulation in plants. Several signaling components, such as guanosine triphosphate (GTP)-binding protein, nucleoside diphosphate kinase, annexin, and brassinosteroid-insensitive I-kinase domain interacting protein 114, were proposed to be important in heat signaling transduction. Moreover, diverse protein patterns of photosynthetic proteins imply that the modulations of stomatal CO₂ exchange, photosystem II, Calvin cycle, ATP synthesis, and chlorophyll biosynthesis are crucial for plant heat tolerance.

Experimental demonstration of high fidelity entanglement distribution over decoherence channels via qubit transduction.

PubMed

Lim, Hyang-Tag; Hong, Kang-Hee; Kim, Yoon-Ho

2015-10-21

Quantum coherence and entanglement, which are essential resources for quantum information, are often degraded and lost due to decoherence. Here, we report a proof-of-principle experimental demonstration of high fidelity entanglement distribution over decoherence channels via qubit transduction. By unitarily switching the initial qubit encoding to another, which is insensitive to particular forms of decoherence, we have demonstrated that it is possible to avoid the effect of decoherence completely. In particular, we demonstrate high-fidelity distribution of photonic polarization entanglement over quantum channels with two types of decoherence, amplitude damping and polarization-mode dispersion, via qubit transduction between polarization qubits and dual-rail qubits. These results represent a significant breakthrough in quantum communication over decoherence channels as the protocol is input-state independent, requires no ancillary photons and symmetries, and has near-unity success probability.

Requirement for a phospholipase C in odor response: overlap between olfaction and vision in Drosophila.

PubMed Central

Riesgo-Escovar, J; Raha, D; Carlson, J R

1995-01-01

A central problem in sensory system biology is the identification of the signal transduction pathways used in different sensory modalities. Genetic analysis of transduction mutants provides a means of studying in vivo the contributions of different pathways. This report shows that odorant response in one olfactory organ of Drosophila melanogaster depends on the norpA phospholipase C (EC 3.1.4.3) gene, providing evidence for use of the inositol 1,4,5-trisphosphate (IP3) signal transduction pathway. Since the norpA gene is also essential to phototransduction, this work demonstrates overlap in the genetic and molecular underpinnings of vision and olfaction. Genetic and molecular data also indicate that some olfactory information flows through a pathway which does not depend on norpA. Images Fig. 1 Fig. 5 PMID:7708738

Experimental demonstration of high fidelity entanglement distribution over decoherence channels via qubit transduction

PubMed Central

Lim, Hyang-Tag; Hong, Kang-Hee; Kim, Yoon-Ho

2015-01-01

Quantum coherence and entanglement, which are essential resources for quantum information, are often degraded and lost due to decoherence. Here, we report a proof-of-principle experimental demonstration of high fidelity entanglement distribution over decoherence channels via qubit transduction. By unitarily switching the initial qubit encoding to another, which is insensitive to particular forms of decoherence, we have demonstrated that it is possible to avoid the effect of decoherence completely. In particular, we demonstrate high-fidelity distribution of photonic polarization entanglement over quantum channels with two types of decoherence, amplitude damping and polarization-mode dispersion, via qubit transduction between polarization qubits and dual-rail qubits. These results represent a significant breakthrough in quantum communication over decoherence channels as the protocol is input-state independent, requires no ancillary photons and symmetries, and has near-unity success probability. PMID:26487083

The styryl dye FM1-43 suppresses odorant responses in a subset of olfactory neurons by blocking cyclic nucleotide-gated (CNG) channels.

PubMed

Breunig, Esther; Kludt, Eugen; Czesnik, Dirk; Schild, Detlev

2011-08-12

Many olfactory receptor neurons use a cAMP-dependent transduction mechanism to transduce odorants into depolarizations. This signaling cascade is characterized by a sequence of two currents: a cation current through cyclic nucleotide-gated channels followed by a chloride current through calcium-activated chloride channels. To date, it is not possible to interfere with these generator channels under physiological conditions with potent and specific blockers. In this study we identified the styryl dye FM1-43 as a potent blocker of native olfactory cyclic nucleotide-gated channels. Furthermore, we characterized this substance to stain olfactory receptor neurons that are endowed with cAMP-dependent transduction. This allows optical differentiation and pharmacological interference with olfactory receptor neurons at the level of the signal transduction.

The Framework of Knowledge Creation for Online Learning Environments

ERIC Educational Resources Information Center

Huang, Hsiu­-Mei; Liaw, Shu­-Sheng

2004-01-01

In today's competitive global economy characterized by knowledge acquisition, the concept of knowledge management has become increasingly prevalent in academic and business practices. Knowledge creation is an important factor and remains a source of competitive advantage over knowledge management. Information technology facilitates knowledge…

Eyes on the prize: reflections on the impact of the evolving digital ecology on the librarian as expert intermediary and knowledge coach, 1969–2009*

PubMed Central

Homan, J. Michael

2010-01-01

Objective: The 2009 Janet Doe Lecture reflects on the continuing value and increasing return on investment of librarian-mediated services in the constantly evolving digital ecology and complex knowledge environment of the health sciences. Setting: The interrelationship of knowledge, decision making based on knowledge, technology used to access and retrieve knowledge, and the important linkage roles of expert librarian intermediaries is examined. Methodology: Professional experiences from 1969 to 2009, occurring during a time of unprecedented changes in the digital ecology of librarianship, are the base on which the evolving role and value of librarians as knowledge coaches and expert intermediaries are examined. Conclusion: Librarian-mediated services linking knowledge and critical decision making in health care have become more valuable than ever as technology continues to reshape an increasingly complex knowledge environment. PMID:20098655

Rhodopsin Kinase Activity in the Mammalian Pineal Gland and Other Tissues

NASA Astrophysics Data System (ADS)

Somers, Robert L.; Klein, David C.

1984-10-01

Rhodopsin kinase, an enzyme involved in photochemical transduction in the retina, has been found in the mammalian pineal gland in amounts equal to those in the retina; other tissues had 7 percent of this amount, or less. This finding suggests that, in mammals, rhodopsin kinase functions in the pineal gland and other tissues to phosphorylate rhodopsin-like integral membrane receptors and is thereby involved in signal transduction.

Delta-Tocotrienol: Radiation Protection and Effects on Signal Transduction Pathways

DTIC Science & Technology

2011-06-15

Delta- Tocotrienol : Radiation Protection and Effects on Signal Transduction Pathways Venkataraman Srinivasan, PhD Mang Xiao, MD Principal...2011 2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Delta- Tocotrienol : Radiation Protection And Effects On...Mechanisms? 17 Survival of γ-irradiated mouse bone marrow and primary human hematopoietic CD34+ cells was significantly enhanced by Delta- tocotrienol (DT3

Naturally enveloped AAV vectors for shielding neutralizing antibodies and robust gene delivery in vivo

PubMed Central

György, Bence; Fitzpatrick, Zachary; Crommentuijn, Matheus HW; Mu, Dakai; Maguire, Casey A.

2014-01-01

Recently adeno-associated virus (AAV) became the first clinically approved gene therapy product in the western world. To develop AAV for future clinical application in a widespread patient base, particularly in therapies which require intravenous (i.v.) administration of vector, the virus must be able to evade pre-existing antibodies to the wild type virus. Here we demonstrate that in mice, AAV vectors associated with extracellular vesicles (EVs) can evade human anti-AAV neutralizing antibodies. We observed different antibody evasion and gene transfer abilities with populations of EVs isolated by different centrifugal forces. EV-associated AAV vector (ev-AAV) was up to 136-fold more resistant over a range of neutralizing antibody concentrations relative to standard AAV vector in vitro. Importantly in mice, at a concentration of passively transferred human antibodies which decreased i.v. administered standard AAV transduction of brain by 80%, transduction of ev-AAV transduction was not reduced and was 4,000-fold higher. Finally, we show that expressing a brain targeting peptide on the EV surface allowed significant enhancement of transduction compared to untargeted ev-AAV. Using ev-AAV represents an effective, clinically relevant approach to evade human neutralizing anti-AAV antibodies after systemic administration of vector. PMID:24917028

Engineering adeno-associated virus 2 vectors for targeted gene delivery to atherosclerotic lesions.

PubMed

White, K; Büning, H; Kritz, A; Janicki, H; McVey, J; Perabo, L; Murphy, G; Odenthal, M; Work, L M; Hallek, M; Nicklin, S A; Baker, A H

2008-03-01

Targeted delivery of biological agents to atherosclerotic plaques may provide a novel treatment and/or useful tool for imaging of atherosclerosis in vivo. However, there are no known viral vectors that possess the desired tropism. Two plaque-targeting peptides, CAPGPSKSC (CAP) and CNHRYMQMC (CNH) were inserted into the capsid of adeno-associated virus 2 (AAV2) to assess vector retargeting. AAV2-CNH produced significantly higher levels of transduction than unmodified AAV2 in human, murine and rat endothelial cells, whereas transduction of nontarget HeLa cells was unaltered. Transduction studies and surface plasmon resonance suggest that AAV2-CNH uses membrane type 1 matrix metalloproteinase as a surface receptor. AAV2-CAP only produced higher levels of transduction in rat endothelial cells, possibly because the virus was found to be affected by proteasomal degradation. In vivo substantially higher levels of both peptide-modified AAV2 vectors was detected in the brachiocephalic artery (site of advanced atherosclerotic plaques) and aorta, whereas reduced levels were detected in all other organs examined. These results suggest that in the AAV2 platform the peptides are exposed on the capsid surface in a way that enables efficient receptor binding and so creates effective atherosclerotic plaque targeted vectors.

Manipulation of light signal transduction as a means of modifying fruit nutritional quality in tomato

PubMed Central

Liu, Yongsheng; Roof, Sherry; Ye, Zhibiao; Barry, Cornelius; van Tuinen, Ageeth; Vrebalov, Julia; Bowler, Chris; Giovannoni, Jim

2004-01-01

Fruit constitutes a major component of human diets, providing fiber, vitamins, and phytonutrients. Carotenoids are a major class of compounds found in many fruits, providing nutritional benefits as precursors to essential vitamins and as antioxidants. Although recent gene isolation efforts and metabolic engineering have primarily targeted genes involved in carotenoid biosynthesis, factors that regulate flux through the carotenoid pathway remain largely unknown. Characterization of the tomato high-pigment mutations (hp1 and hp2) suggests the manipulation of light signal transduction machinery may be an effective approach toward practical manipulation of plant carotenoids. We demonstrate here that hp1 alleles represent mutations in a tomato UV-DAMAGED DNA-BINDING PROTEIN 1 (DDB1) homolog. We further demonstrate that two tomato light signal transduction genes, LeHY5 and LeCOP1LIKE, are positive and negative regulators of fruit pigmentation, respectively. Down-regulated LeHY5 plants exhibit defects in light responses, including inhibited seedling photomorphogenesis, loss of thylakoid organization, and reduced carotenoid accumulation. In contrast, repression of LeCOP1LIKE expression results in plants with exaggerated photomorphogenesis, dark green leaves, and elevated fruit carotenoid levels. These results suggest genes encoding components of light signal transduction machinery also influence fruit pigmentation and represent genetic tools for manipulation of fruit quality and nutritional value. PMID:15178762

Dual targeting of gene delivery by genetic modification of adenovirus serotype 5 fibers and cell-selective transcriptional control.

PubMed

Work, L M; Ritchie, N; Nicklin, S A; Reynolds, P N; Baker, A H

2004-08-01

Adenovirus (Ad)-mediated gene delivery is a promising approach for genetic manipulation of the vasculature and is being used in both preclinical models and clinical trials. However, safety concerns relating to infection of nontarget tissue and the poor infectivity of vascular cells compared to other cell types necessitates Ad vector refinement. Here, we combine a transductional targeting approach to improve vascular cell infectivity through RGD peptide insertion into adenovirus fibers, combined with transcriptional targeting to endothelial cells using a approximately 1 kb fragment of the fms-like tyrosine kinase receptor-1 (FLT-1) promoter. Single- and double-modified vectors were characterized in human cell lines that either support or have silenced FLT-1 expression. In rat hepatocytes and endothelial cells, the double modification substantially shifted transduction profiles toward vascular endothelial cells. Furthermore, in intact aortae derived from spontaneously hypertensive rats that display enhanced alphav integrin expression on dysfunctional endothelium, enhanced levels of transduction were observed using the double-modified vector but not in aortae derived from normotensive control rats. Our data indicate that Ad-mediated transduction can be beneficially modified in vitro and in vivo by combining fiber modification and a cell-selective promoter within a single-component vector system.

Efficient Generation of Functional Hepatocytes From Human Embryonic Stem Cells and Induced Pluripotent Stem Cells by HNF4α Transduction

PubMed Central

Takayama, Kazuo; Inamura, Mitsuru; Kawabata, Kenji; Katayama, Kazufumi; Higuchi, Maiko; Tashiro, Katsuhisa; Nonaka, Aki; Sakurai, Fuminori; Hayakawa, Takao; Kusuda Furue, Miho; Mizuguchi, Hiroyuki

2012-01-01

Hepatocyte-like cells from human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are expected to be a useful source of cells drug discovery. Although we recently reported that hepatic commitment is promoted by transduction of SOX17 and HEX into human ESC- and iPSC-derived cells, these hepatocyte-like cells were not sufficiently mature for drug screening. To promote hepatic maturation, we utilized transduction of the hepatocyte nuclear factor 4α (HNF4α) gene, which is known as a master regulator of liver-specific gene expression. Adenovirus vector-mediated overexpression of HNF4α in hepatoblasts induced by SOX17 and HEX transduction led to upregulation of epithelial and mature hepatic markers such as cytochrome P450 (CYP) enzymes, and promoted hepatic maturation by activating the mesenchymal-to-epithelial transition (MET). Thus HNF4α might play an important role in the hepatic differentiation from human ESC-derived hepatoblasts by activating the MET. Furthermore, the hepatocyte like-cells could catalyze the toxication of several compounds. Our method would be a valuable tool for the efficient generation of functional hepatocytes derived from human ESCs and iPSCs, and the hepatocyte-like cells could be used for predicting drug toxicity. PMID:22068426

Enhanced retroviral gene delivery in ultrasonic standing wave fields.

PubMed

Lee, Y-H; Peng, C-A

2005-04-01

Enhancement of retroviral transduction efficiency has been achieved by several physical and chemical approaches. However, the application of those methods is hampered by not easily scalable configurations. In this study, instead of looking into the effect of sonoporation, the potential of ultrasonic standing wave fields (USWF) to facilitate retroviral transduction rate was explored. We reasoned that, driven by the primary acoustic radiation force, suspended cells moved to the pressure nodal planes first and formed cell bands. Nanometer-sized retroviruses, circulated between nodal planes by acoustic microstreaming, then used the preformed cell bands as the nucleating sites to attach on. As a result, the encounter opportunity between retroviruses and cells was increased and further facilitated the gene delivery efficiency. Our results showed that mega-Hertz USWF brought K562 erythroleukemia cells (10(6) cells/ml) and vesicular stomatitis virus G-protein (VSV-G) pseudotyped retroviruses (titer of 5 x 10(6) CFU/ml) into close contact at the pressure nodal planes, yielding a four-fold increment of enhanced green fluorescent protein transgene expression after 5-min USWF exposure in the presence of Polybrene. Furthermore, with a fixed titer of retrovirus, the transduction rate was augmented with the increase of cell concentration. In summary, USWF offer a feasible means to enhance retroviral transduction efficiency in large-scale settings.

Template Authoring Environment for the Automatic Generation of Narrative Content

ERIC Educational Resources Information Center

Caropreso, Maria Fernanda; Inkpen, Diana; Keshtkar, Fazel; Khan, Shahzad

2012-01-01

Natural Language Generation (NLG) systems can make data accessible in an easily digestible textual form; but using such systems requires sophisticated linguistic and sometimes even programming knowledge. We have designed and implemented an environment for creating and modifying NLG templates that requires no programming knowledge, and can operate…

Family Child Care Learning Environments: Caregiver Knowledge and Practices Related to Early Literacy and Mathematics

ERIC Educational Resources Information Center

Phillips, Beth M.; Morse, Erika E.

2011-01-01

This paper presents findings from a stratified-random survey of family child care providers' backgrounds, caregiving environments, practices, attitudes, and knowledge related to language, literacy, and mathematics development for preschool children. Descriptive results are consistent with prior studies suggesting that home-based providers are…

Environmental Knowledge, Attitudes, and Behavior in Dutch Secondary Education.

ERIC Educational Resources Information Center

Kuhlemeier, Hans; van den Bergh, Huub; Lagerweij, Nijs

1999-01-01

In a national assessment program, 57% of Dutch ninth-grade students had a positive attitude towards the environment and 35% were prepared to make sacrifices for the environment. Student knowledge about environmental problems, however, was fragmentary and often incorrect. Environmentally responsible behavior was more strongly connected with the…