245 research outputs found
Attenuated live infectious bronchitis virus QX vaccine disseminates slowly to target organs distant from the site of inoculation
Infectious bronchitis (IB) is a highly contagious respiratory disease of poultry, caused by the avian coronavirus infectious bronchitis virus (IBV). Currently, one of the most relevant genotypes circulating worldwide is IBV-QX (GI-19), for which vaccines have been developed by passaging virulent QX strains in embryonated chicken eggs. Here we explored the attenuated phenotype of a commercially available QX live vaccine, IB Primo QX, in specific pathogens free broilers. At hatch, birds were inoculated with QX vaccine or its virulent progenitor IBV-D388, and postmortem swabs and tissues were collected each day up to eight days post infection to assess viral replication and morphological changes. In the trachea, viral RNA replication and protein expression were comparable in both groups. Both viruses induced morphologically comparable lesions in the trachea, albeit with a short delay in the vaccinated birds. In contrast, in the kidney, QX vaccine viral RNA was nearly absent, which coincided with the lack of any morphological changes in this organ. This was in contrast to high viral RNA titers and abundant lesions in the kidney after IBV D388 infection. Furthermore, QX vaccine showed reduced ability to reach and replicate in conjunctivae and intestines including cloaca, resulting in significantly lower titers and delayed protein expression, respectively. Nephropathogenic IBVs might reach the kidney also via an ascending route from the cloaca, based on our observation that viral RNA was detected in the cloaca one day before detection in the kidney. In the kidney distal tubular segments, collecting ducts and ureter were positive for viral antigen. Taken together, the attenuated phenotype of QX vaccine seems to rely on slower dissemination and lower replication in target tissues other than the site of inoculation
The Paradox of Power in CSR: A Case Study on Implementation
Purpose Although current literature assumes positive outcomes for stakeholders resulting from an increase in power associated with CSR, this research suggests that this increase can lead to conflict within organizations, resulting in almost complete inactivity on CSR.
Methods A single in-depth case study, focusing on power as an embedded concept.
Results Empirical evidence is used to demonstrate how some actors use CSR to improve their own positions within an organization. Resource dependence theory is used to highlight why this may be a more significant concern for CSR.
Conclusions Increasing power for CSR has the potential to offer actors associated with it increased personal power, and thus can attract opportunistic actors with little interest in realizing the benefits of CSR for the company and its stakeholders. Thus power can be an impediment to furthering CSR strategy and activities at the individual and organizational level
A protein methylation pathway in Chlamydomonas flagella is active during flagellar resorption
Author Posting. © American Society for Cell Biology, 2008. This article is posted here by permission of American Society for Cell Biology for personal use, not for redistribution. The definitive version was published in Molecular Biology of the Cell 19 (2008): 4319-4327, doi:10.1091/mbc.E08-05-0470.During intraflagellar transport (IFT), the regulation of motor proteins, the loading and unloading of cargo and the turnover of flagellar proteins all occur at the flagellar tip. To begin an analysis of the protein composition of the flagellar tip, we used difference gel electrophoresis to compare long versus short (i.e., regenerating) flagella. The concentration of tip proteins should be higher relative to that of tubulin (which is constant per unit length of the flagellum) in short compared with long flagella. One protein we have identified is the cobalamin-independent form of methionine synthase (MetE). Antibodies to MetE label flagella in a punctate pattern reminiscent of IFT particle staining, and immunoblot analysis reveals that the amount of MetE in flagella is low in full-length flagella, increased in regenerating flagella, and highest in resorbing flagella. Four methylated proteins have been identified in resorbing flagella, using antibodies specific for asymmetrically dimethylated arginine residues. These proteins are found almost exclusively in the axonemal fraction, and the methylated forms of these proteins are essentially absent in full-length and regenerating flagella. Because most cells resorb cilia/flagella before cell division, these data indicate a link between flagellar protein methylation and progression through the cell cycle.This work was supported by National Institutes
of Health Grant DK071720 (R.D.S.) and National Science Foundation Grant
MCB 0418877 (R.D.S.)
A Mathematical model for Astrocytes mediated LTP at Single Hippocampal Synapses
Many contemporary studies have shown that astrocytes play a significant role
in modulating both short and long form of synaptic plasticity. There are very
few experimental models which elucidate the role of astrocyte over Long-term
Potentiation (LTP). Recently, Perea & Araque (2007) demonstrated a role of
astrocytes in induction of LTP at single hippocampal synapses. They suggested a
purely pre-synaptic basis for induction of this N-methyl-D- Aspartate (NMDA)
Receptor-independent LTP. Also, the mechanisms underlying this pre-synaptic
induction were not investigated. Here, in this article, we propose a
mathematical model for astrocyte modulated LTP which successfully emulates the
experimental findings of Perea & Araque (2007). Our study suggests the role of
retrograde messengers, possibly Nitric Oxide (NO), for this pre-synaptically
modulated LTP.Comment: 51 pages, 15 figures, Journal of Computational Neuroscience (to
appear
An active learning based classification strategy for the minority class problem: application to histopathology annotation
The Golgin GMAP210/TRIP11 Anchors IFT20 to the Golgi Complex
Eukaryotic cells often use proteins localized to the ciliary membrane to monitor the extracellular environment. The mechanism by which proteins are sorted, specifically to this subdomain of the plasma membrane, is almost completely unknown. Previously, we showed that the IFT20 subunit of the intraflagellar transport particle is localized to the Golgi complex, in addition to the cilium and centrosome, and hypothesized that the Golgi pool of IFT20 plays a role in sorting proteins to the ciliary membrane. Here, we show that IFT20 is anchored to the Golgi complex by the golgin protein GMAP210/Trip11. Mice lacking GMAP210 die at birth with a pleiotropic phenotype that includes growth restriction, ventricular septal defects of the heart, omphalocele, and lung hypoplasia. Cells lacking GMAP210 have normal Golgi structure, but IFT20 is no longer localized to this organelle. GMAP210 is not absolutely required for ciliary assembly, but cilia on GMAP210 mutant cells are shorter than normal and have reduced amounts of the membrane protein polycystin-2 localized to them. This work suggests that GMAP210 and IFT20 function together at the Golgi in the sorting or transport of proteins destined for the ciliary membrane
The Gene Regulatory Cascade Linking Proneural Specification with Differentiation in Drosophila Sensory Neurons
Temporal expression profiling of sensory precursor cells reveals how the atonal proneural transcription factor regulates a specialized neuronal differentiation pathway
Embracing open innovation to acquire external ideas and technologies and to transfer internal ideas and technologies outside
The objective of this dissertation is to increase understanding of how organizations can embrace open innovation in order to acquire external ideas and technologies from outside the organization, and to transfer internal ideas and technologies to outside the organization. The objective encompasses six sub-objectives, each addressed in one or more substudies. Altogether, the dissertation consists of nine substudies and a compendium summarizing the substudies.
An extensive literature review was conducted on open innovation and crowdsourcing literature (substudies 1–4). In the subsequent empirical substudies, both qualitative research methods (substudies 5–7) and quantitative research methods (substudies 8–9) were applied. The four literature review substudies provided insights on the body of knowledge on open innovation and crowdsourcing. These substudies unveiled most of the influential articles, authors, and journals of open innovation and crowdsourcing disciplines. Moreover, they identified research gaps in the current literature.
The empirical substudies offer several insightful findings. Substudy 5 shows how non-core ideas and technologies of a large firm can become valuable, especially for small firms. Intermediary platforms can find solutions to many pressing problems of large organizations by engaging renowned scientists from all over world (substudy 6). Intermediary platforms can also bring breakthrough innovations with novel mechanisms (substudy 7). Large firms are not only able to garner ideas by engaging their customers through crowdsourcing but they can also build long-lasting relations with their customers (substudies 8 and 9). Embracing open innovation brings challenges for firms too.
Firms need to change their organizational structures in order to be able to fully benefit from open innovation. When crowdsourcing is successful, it produces a very large number of new ideas. This has the consequence that firms need to allocate a significant amount of resources in order to identify the most promising ideas. In an idea contest, customarily, only one or a few best ideas are rewarded (substudy 7). Sometimes, no reward is provided for the selected idea (substudies 8 and 9). Most of the ideas that are received are not implemented in practice
Equity Ownership Strategy in Greenfield Investments : Influences of Host Country Infrastructure and MNE Resources in Emerging Markets
This chapter addresses equity ownership strategy in greenfield investments by multinational enterprises (MNEs) in the emerging markets (EMs). It is one of the few studies to hypothesize and analyze influences of host EM physical infrastructure in relation to investment decisions of MNEs. We use resource dependence theory (RDT) as a theoretical basis and test the moderating effects of firm resources like size and host country investment experience. Moreover, the current study assumes a more nuanced approach to studying equity ownership by analyzing wholly owned subsidiaries versus joint ventures (JVs) and including majority versus minority JVs in the analysis as well. The empirical results based on greenfield investments undertaken by Nordic (Danish, Finnish, Norwegian, and Swedish) MNEs in EMs during 1990–2015 reveals the importance of host country physical infrastructure for high equity ownership strategy. Moreover, host country investment experience moderates the effect of physical infrastructure on equity ownership strategy. Finally, the analysis of a sub-sample of greenfield JVs reveals that determinants of equity ownership strategy differ somewhat between greenfield JV or greenfield wholly owned subsidiaries (WOS).© The Author(s) 2019.fi=vertaisarvioitu|en=peerReviewed
Calmodulin Activation by Calcium Transients in the Postsynaptic Density of Dendritic Spines
The entry of calcium into dendritic spines can trigger a sequence of biochemical reactions that begins with the activation of calmodulin (CaM) and ends with long-term changes to synaptic strengths. The degree of activation of CaM can depend on highly local elevations in the concentration of calcium and the duration of transient increases in calcium concentration. Accurate measurement of these local changes in calcium is difficult because the spaces are so small and the numbers of molecules are so low. We have therefore developed a Monte Carlo model of intracellular calcium dynamics within the spine that included calcium binding proteins, calcium transporters and ion channels activated by voltage and glutamate binding. The model reproduced optical recordings using calcium indicator dyes and showed that without the dye the free intracellular calcium concentration transient was much higher than predicted from the fluorescent signal. Excitatory postsynaptic potentials induced large, long-lasting calcium gradients across the postsynaptic density, which activated CaM. When glutamate was released at the synapse 10 ms before an action potential occurred, simulating activity patterns that strengthen hippocampal synapses, the calcium gradient and activation of CaM in the postsynaptic density were much greater than when the order was reversed, a condition that decreases synaptic strengths, suggesting a possible mechanism underlying the induction of long-term changes in synaptic strength. The spatial and temporal mechanisms for selectivity in CaM activation demonstrated here could be used in other signaling pathways
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