265 research outputs found
Tektin 2 is required for central spindle microtubule organization and the completion of cytokinesis
During anaphase, the nonkinetochore microtubules in the spindle midzone become compacted into the central spindle, a structure which is required to both initiate and complete cytokinesis. We show that Tektin 2 (Tek2) associates with the spindle poles throughout mitosis, organizes the spindle midzone microtubules during anaphase, and assembles into the midbody matrix surrounding the compacted midzone microtubules during cytokinesis. Tek2 small interfering RNA (siRNA) disrupts central spindle organization and proper localization of MKLP1, PRC1, and Aurora B to the midzone and prevents the formation of a midbody matrix. Video microscopy revealed that loss of Tek2 results in binucleate cell formation by aberrant fusion of daughter cells after cytokinesis. Although a myosin II inhibitor, blebbistatin, prevents actin-myosin contractility, the microtubules of the central spindle are compacted. Strikingly, Tek2 siRNA abolishes this actin-myosin–independent midzone microtubule compaction. Thus, Tek2-dependent organization of the central spindle during anaphase is essential for proper midbody formation and the segregation of daughter cells after cytokinesis
Marketing technology for adoption by small business
The adoption of technology for marketing is essential for the survival of small businesses and yet little is understood about owner-manager practice in this area. This paper aims to address that gap through a qualitative study of 24 owner-managed small businesses operating in the visitor economy. It found that there was a strong appetite for the adoption of technology for marketing and a clear recognition of its opportunities particularly related to how it could create a stronger market orientation and more agile marketing, adhering to the principles of effectual reasoning. However, the ability to take advantage of these opportunities was constrained by a lack of knowledge and in particular an inability to measure the return on investment. While the wider implications of the study are limited by the niche sample, a planning model for the adoption of technology for marketing is presented which can be tested through future research
Evaluation of Dynamic Cell Processes and Behavior Using Video Bioinformatics Tools
Just as body language can reveal a person’s state of well-being, dynamic changes in cell behavior and
morphology can be used to monitor processes in cultured cells. This chapter discusses how CL-Quant
software, a commercially available video bioinformatics tool, can be used to extract quantitative data on:
(1) growth/proliferation, (2) cell and colony migration, (3) reactive oxygen species (ROS) production, and
(4) neural differentiation. Protocols created using CL-Quant were used to analyze both single cells and
colonies. Time-lapse experiments in which different cell types were subjected to various chemical
exposures were done using Nikon BioStations. Proliferation rate was measured in human embryonic stem
cell colonies by quantifying colony area (pixels) and in single cells by measuring confluency (pixels).
Colony and single cell migration were studied by measuring total displacement (distance between the
starting and ending points) and total distance traveled by the colonies/cells. To quantify ROS production,
cells were pre-loaded with MitoSOX Red™, a mitochondrial ROS (superoxide) indicator, treated with
various chemicals, then total intensity of the red fluorescence was measured in each frame. Lastly, neural
stem cells were incubated in differentiation medium for 12 days, and time lapse images were collected
daily. Differentiation of neural stem cells was quantified using a protocol that detects young neurons. CLQuant
software can be used to evaluate biological processes in living cells, and the protocols developed in
this project can be applied to basic research and toxicological studies, or to monitor quality control in
culture facilities
Rethinking the employability of international graduate migrants: reflections on the experiences of Zimbabweans with degrees from England
The last decade has seen the rise of literatures that have focused on the rapid expansion of the numbers of international students in higher education globally and the growing policy discourse around improving graduate employability. However, both, inevitably, have limitations. Together, they tend to homogenise international learners and see them narrowly as simply economic actors. More recently, however, there have been signs of important new developments in both literatures, drawing on interactive employability and capability accounts that stress both agency and structure in more satisfactory ways. We seek to further the development of an account that bridges the new wave of student mobility research and the capability-employability account. In doing so, we offer two further elements to the literature. First, we aim to bridge the gap between international higher education accounts and those of migration and diasporic studies. Second, we deliberately focus on a group that is marginal to the mainstream discourse but who are migrants that have engaged in international higher education in order to improve their labour market prospects, amongst other motivations. We do this through examining the stories of five Zimbabweans who embarked on additional higher educational studies in England after migrating to the country. Through this unique approach, we offer an important new perspective on how the debates on international higher education, employability and migration can be taken forward through closer articulation between these accounts
Long-term efficacy and tolerability of TNFα inhibitors in the treatment of non-infectious ocular inflammation: an 8-year prospective surveillance study
Background/Aim To report the efficacy and tolerability
of antitumour necrosis factor-alpha therapy (TNF
inhibitors [TNFi]) in the management of non-infectious
ocular inflammation, including uveitis and scleritis, in
adult patients over an 8-year period.
Materials and methods This is a prospective cohort
study of infliximab and adalimumab in the treatment
of non-infectious ocular inflammatory disease. 43 of 85
adult patients on TNFi (34 infliximab, 9 adalimumab)
for ≥1 year with non-infectious uveitis or scleritis were
followed from 2006 to 2014. Clinical assessments,
medication, adverse events and history of steroid rescues
were collected at 6 monthly intervals. General quality
of life (Short Form Health Survey (SF-36)) and visual
quality of life (Vision-related quality of life Core Measure
(VCM1)) were assessed annually. Outcome measures
included rate of sustained remission, rate of relapse,
systemic corticosteroid reduction, adverse events, and
VCM1 and SF-36 scores.
Results The median time on infliximab was 3.2 years
(IQR 4.3) and on adalimumab was 2.4 years (IQR 1.8).
Sustained remission was induced in 39 patients (91%)
(0.5 per patient year) after a median of 1.2 years
on a TNFi. 22 (51%) experienced one relapse, and 5
(12%) had two relapses. 23 (54%) had at least one
adverse event; serious adverse events necessitating
hospitalisation or cessation of medication occurred in
four (9%) patients. 10 patients (23%) switched from the
initiation of TNFi, at 1.7 years after starting, to another
TNFi or another class of biologic therapy.
Conclusion TNFi treatment is associated with longterm drug-induced remission of ocular inflammation,
visual stability and corticosteroid reduction. Adverse
events were common and no new safety signals
occurred. Relapse of inflammation occurs in half of the
treated population
PKA and PDE4D3 anchoring to AKAP9 provides distinct regulation of cAMP signals at the centrosome
Previous work has shown that the protein kinase A (PKA)–regulated phosphodiesterase (PDE) 4D3 binds to A kinase–anchoring proteins (AKAPs). One such protein, AKAP9, localizes to the centrosome. In this paper, we investigate whether a PKA–PDE4D3–AKAP9 complex can generate spatial compartmentalization of cyclic adenosine monophosphate (cAMP) signaling at the centrosome. Real-time imaging of fluorescence resonance energy transfer reporters shows that centrosomal PDE4D3 modulated a dynamic microdomain within which cAMP concentration selectively changed over the cell cycle. AKAP9-anchored, centrosomal PKA showed a reduced activation threshold as a consequence of increased autophosphorylation of its regulatory subunit at S114. Finally, disruption of the centrosomal cAMP microdomain by local displacement of PDE4D3 impaired cell cycle progression as a result of accumulation of cells in prophase. Our findings describe a novel mechanism of PKA activity regulation that relies on binding to AKAPs and consequent modulation of the enzyme activation threshold rather than on overall changes in cAMP levels. Further, we provide for the first time direct evidence that control of cell cycle progression relies on unique regulation of centrosomal cAMP/PKA signals
Joint Resummation for Higgs Production
We study the application of the joint resummation formalism to Higgs
production via gluon-gluon fusion at the LHC, defining inverse transforms by
analytic continuation. We work at next-to-leading logarithmic accuracy. We find
that at low Q_T the resummed Higgs Q_T distributions are comparable in the
joint and pure-Q_T formalisms, with relatively small influence from threshold
enhancement in this range. We find a modest (about ten percent) decrease in the
inclusive cross section, relative to pure threshold resummation.Comment: 22 pages, LaTeX, 5 figures as eps file
Amphiastral Mitotic Spindle Assembly in Vertebrate Cells Lacking Centrosomes
The role of centrosomes/centrioles during mitotic spindle assembly in vertebrates remains controversial. In cell-free extracts and experimentally derived acentrosomal cells, randomly oriented microtubules (MTs) self-organize around mitotic chromosomes and assemble anastral spindles [1, 2, 3]. However, vertebrate somatic cells normally assemble a connected pair of polarized, astral MT arrays – termed an amphiaster (“a star on both sides” [4]) – that is formed by the splitting and separation of the microtubule-organizing center (MTOC) well before nuclear envelope breakdown (NEB) [5]. Whether amphiaster formation requires splitting of duplicated centrosomes is not known. We found that when centrosomes were removed from living vertebrate cells early in their cell cycle, an acentriolar MTOC re-assembled, and prior to NEB, a functional amphiastral spindle formed. Cytoplasmic dynein, dynactin, and pericentrin are all recruited to the interphase aMTOC, and the activity of kinesin-5 is needed for amphiaster formation. Mitosis proceeded on time and these karyoplasts divided in two. However, ~35% of aMTOCs failed to split/separate before NEB, and these entered mitosis with persistent monastral spindles. The chromatin-mediated RAN-GTP pathway could not restore bipolarity to monastral spindles, and these cells exited mitosis as single daughters. Our data reveal the novel finding that MTOC separation and amphiaster formation does not absolutely require the centrosome, but in its absence, the fidelity of bipolar spindle assembly is highly compromised
Intranasal H5N1 vaccines, adjuvanted with chitosan derivatives, protect ferrets against highly pathogenic influenza intranasal and intratracheal challenge
We investigated the protective efficacy of two intranasal chitosan (CSN and TM-CSN) adjuvanted H5N1 Influenza vaccines against highly pathogenic avian Influenza (HPAI) intratracheal and intranasal challenge in a ferret model. Six groups of 6 ferrets were intranasally vaccinated twice, 21 days apart, with either placebo, antigen alone, CSN adjuvanted antigen, or TM-CSN adjuvanted antigen. Homologous and intra-subtypic antibody cross-reacting responses were assessed. Ferrets were inoculated intratracheally (all treatments) or intranasally (CSN adjuvanted and placebo treatments only) with clade 1 HPAI A/Vietnam/1194/2004 (H5N1) virus 28 days after the second vaccination and subsequently monitored for morbidity and mortality outcomes. Clinical signs were assessed and nasal as well as throat swabs were taken daily for virology. Samples of lung tissue, nasal turbinates, brain, and olfactory bulb were analysed for the presence of virus and examined for histolopathological findings. In contrast to animals vaccinated with antigen alone, the CSN and TM-CSN adjuvanted vaccines induced high levels of antibodies, protected ferrets from death, reduced viral replication and abrogated disease after intratracheal challenge, and in the case of CSN after intranasal challenge. In particular, the TM-CSN adjuvanted vaccine was highly effective at eliciting protective immunity from intratrache
Fluorescent dyes as a probe for the localized field of coupled surface plasmon-related resonances
M. Kreiter, T. Neumann, S. Mittler, W. Knoll, and J. Roy Sambles, Physical Review B, Vol. 64, article 075406 (2001). "Copyright © 2001 by the American Physical Society."The fluorescence light of Cy5 dye molecules in the vicinity of a metal grating is studied for varying directions of both the exciting and the emitted light. A different angular dependence of the intensity of the emitted light is observed for different directions of excitation. Model calculations that take into account the localization of the electrical field of grating-coupled surface plasmon-related resonances are in good agreement with the experimental observations. In addition, the spatially inhomogenous photobleaching of the dye in the field of the coupled resonances is experimentally observed. These results can be viewed both as a way to use chromophores as molecular probes for the localized electrical near field of coupled surface plasmon-related resonances and as a way to manipulate dye molecules on a submicron scale
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