39 research outputs found
Comparative ecology of the European eel, Anguilla anguilla (L.1758), in a large Iberian river
A total of 1,816 eels were sampled in
1988, from seven sampling areas. Four areas were
located in brackish water and the remaining three
were located in freshwater reaches of the
Tagus river basin. Eels were more abundant in
the middle estuary and decreased both in the
upstream and in the downstream directions, with
a predominance of males in higher density areas.
Smaller individuals preferred more peripheral areas, such as margins and upper reaches in the
brackish water zone, and the tributaries of the
freshwater habitats. It was assumed that this
distribution pattern resulted from three main
factors: (i) the dominance of larger specimens;
(ii) the need to avoid predators and; (iii) the
search for better trophic conditions. The condition
of the individuals generally decreased toward
the upper reaches, apparently due to a corresponding
decrease in feeding intensity. The presence
of the Belver dam in the main river, 158 km
upstream from the sea, seemed to impose major
alterations to the described patterns. The concentration
of specimens below this impassable
obstacle yielded a reduction in the proportion of
females and a decrease in the condition and
survival of the eels, contributing to a reduction in
the spawning success of this population. Suggestions
to diminish the effects of the dam, and to
preserve the fishery are also presente
FOX-2 Dependent Splicing of Ataxin-2 Transcript Is Affected by Ataxin-1 Overexpression
Alternative splicing is a fundamental posttranscriptional mechanism for controlling gene expression, and splicing defects have been linked to various human disorders. The splicing factor FOX-2 is part of a main protein interaction hub in a network related to human inherited ataxias, however, its impact remains to be elucidated. Here, we focused on the reported interaction between FOX-2 and ataxin-1, the disease-causing protein in spinocerebellar ataxia type 1. In this line, we further evaluated this interaction by yeast-2-hybrid analyses and co-immunoprecipitation experiments in mammalian cells. Interestingly, we discovered that FOX-2 localization and splicing activity is affected in the presence of nuclear ataxin-1 inclusions. Moreover, we observed that FOX-2 directly interacts with ataxin-2, a protein modulating spinocerebellar ataxia type 1 pathogenesis. Finally, we provide evidence that splicing of pre-mRNA of ataxin-2 depends on FOX-2 activity, since reduction of FOX-2 levels led to increased skipping of exon 18 in ataxin-2 transcripts. Most striking, we observed that ataxin-1 overexpression has an effect on this splicing event as well. Thus, our results demonstrate that FOX-2 is involved in splicing of ataxin-2 transcripts and that this splicing event is altered by overexpression of ataxin-1
Centrioles: active players or passengers during mitosis?
Centrioles are cylinders made of nine microtubule (MT) triplets present in many eukaryotes. Early studies, where centrosomes were seen at the poles of the mitotic spindle led to their coining as “the organ for cell division”. However, a variety of subsequent observational and functional studies showed that centrosomes might not always be essential for mitosis. Here we review the arguments in this debate. We describe the centriole structure and its distribution in the eukaryotic tree of life and clarify its role in the organization of the centrosome and cilia, with an historical perspective. An important aspect of the debate addressed in this review is how centrioles are inherited and the role of the spindle in this process. In particular, germline inheritance of centrosomes, such as their de novo formation in parthenogenetic species, poses many interesting questions. We finish by discussing the most likely functions of centrioles and laying out new research avenues
Over-elongation of centrioles in cancer promotes centriole amplification and chromosome missegregation
G.M. and A.G. were funded by the FCT-Harvard Medical School Program Portugal grant (HMSP-CT/SAU-ICT/0075/2009) and individual FCT post-doctoral fellowships (SFRH/BPD/98439/2013 and SFRH/BPD/82420/2011, respectively). The M.B-D. laboratory is supported by IGC, an EMBO installation grant, ERC grant ERC-2010-StG-261344, FCT grants (FCT Investigator to M.B-D., POCI-01-0145-FEDER-016390 and PTDC/BIM-ONC/6858/2014) and a FCT-Harvard Medical School Program Portugal grant (HMSP-CT/SAU-ICT/0075/2009)
Micro-connectomics: probing the organization of neuronal networks at the cellular scale.
Defining the organizational principles of neuronal networks at the cellular scale, or micro-connectomics, is a key challenge of modern neuroscience. In this Review, we focus on graph theoretical parameters of micro-connectome topology, often informed by economical principles that conceptually originated with Ramón y Cajal's conservation laws. First, we summarize results from studies in intact small organisms and in samples from larger nervous systems. We then evaluate the evidence for an economical trade-off between biological cost and functional value in the organization of neuronal networks. Various results suggest that many aspects of neuronal network organization are indeed the outcome of competition between these two fundamental selection pressures.This work was supported by the National Institute of Health Research (NIHR) Cambridge Biomedical Research Centre.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by the Nature Publishing Group
The Compact Linear Collider (CLIC) - 2018 Summary Report
The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and future developments. It presents the CLIC physics potential and reports on design, technology, and implementation aspects of the accelerator and the detector. CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. CLIC uses a two-beam acceleration scheme, in which 12 GHz accelerating structures are powered via a high-current drive beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments and system tests have resulted in an increased energy efficiency (power around 170 MW) for the 380 GeV stage, together with a reduced cost estimate at the level of 6 billion CHF. The detector concept has been refined using improved software tools. Significant progress has been made on detector technology developments for the tracking and calorimetry systems. A wide range of CLIC physics studies has been conducted, both through full detector simulations and parametric studies, together providing a broad overview of the CLIC physics potential. Each of the three energy stages adds cornerstones of the full CLIC physics programme, such as Higgs width and couplings, top-quark properties, Higgs self-coupling, direct searches, and many precision electroweak measurements. The interpretation of the combined results gives crucial and accurate insight into new physics, largely complementary to LHC and HL-LHC. The construction of the first CLIC energy stage could start by 2026. First beams would be available by 2035, marking the beginning of a broad CLIC physics programme spanning 25-30 years
Thigh-length compression stockings and DVT after stroke
Controversy exists as to whether neoadjuvant chemotherapy improves survival in patients with invasive bladder cancer, despite randomised controlled trials of more than 3000 patients. We undertook a systematic review and meta-analysis to assess the effect of such treatment on survival in patients with this disease