320 research outputs found
Risikofaktoren für Probleme mit exzessiver Computer- und Internetnutzung von 14- bis 17-jährigen Jugendlichen in Deutschland: Ergebnisse einer deutschlandweiten Repräsentativerhebung
"In dem vorliegenden Artikel wird zunächst ein Modell vorgestellt, mit Hilfe
dessen Probleme mit exzessiver Computer- und Internetnutzung von Jugendlichen
aus drei Perspektiven abgebildet werden können: die wissenschaftlichobjektive
Perspektive, die subjektive Perspektive der Eltern und die subjektive
Perspektive der Jugendlichen. Datengrundlage bildet eine Repräsentativerhebung
von 1744 Jugendlichen zwischen 14 und 17 Jahren in Deutschland
sowie jeweils einem dazugehörigen Elternteil. Des Weiteren werden mit einer
logistischen Regression Risikofaktoren wie Geschlecht, Sozialstatus, Familienklima
und Nutzungszeiten dahingehend untersucht, inwieweit sie die Wahrscheinlichkeit
erhöhen können, zur problematischsten Gruppe zu gehören." (Autorenreferat)"The article begins with the introduction of a model that intends to capture
the problems resulting from excessive computer and internet use by adolescents.
The model contains three perspectives: the scientific-objective perspective,
the subjective perspective of parents and the subjective perspective
of adolescents. The data basis for this is a representative survey of 1744
adolescents in Germany (aged 14 to 17) including one parent per adolescent.
In addition, the article uses a logistic regression to investigate if riskfactors
like gender, social state, emotional family environment and amount
of adolescent’s internet use might enhance the probability of being part of
the most problematic sub-group." (author's abstract
α2-adrenoceptor blockade accelerates the neurogenic, neurotrophic, and behavioral effects of chronic antidepressant treatment
Slow-onset adaptive changes that arise from sustained antidepressant treatment, such as enhanced adult hippocampal neurogenesis and increased trophic factor expression, play a key role in the behavioral effects of antidepressants. alpha(2)-Adrenoceptors contribute to the modulation of mood and are potential targets for the development of faster acting antidepressants. We investigated the influence of alpha(2)-adrenoceptors on adult hippocampal neurogenesis. Our results indicate that alpha(2)-adrenoceptor agonists, clonidine and guanabenz, decrease adult hippocampal neurogenesis through a selective effect on the proliferation, but not the survival or differentiation, of progenitors. These effects persist in dopamine beta-hydroxylase knock-out (Dbh(-/-)) mice lacking norepinephrine, supporting a role for alpha(2)-heteroceptors on progenitor cells, rather than alpha(2)-autoreceptors on noradrenergic neurons that inhibit norepinephrine release. Adult hippocampal progenitors in vitro express all the alpha(2)-adrenoceptor subtypes, and decreased neurosphere frequency and BrdU incorporation indicate direct effects of alpha(2)-adrenoceptor stimulation on progenitors. Furthermore, coadministration of the alpha(2)-adrenoceptor antagonist yohimbine with the antidepressant imipramine significantly accelerates effects on hippocampal progenitor proliferation, the morphological maturation of newborn neurons, and the increase in expression of brain derived neurotrophic factor and vascular endothelial growth factor implicated in the neurogenic and behavioral effects of antidepressants. Finally, short-duration (7 d) yohimbine and imipramine treatment results in robust behavioral responses in the novelty suppressed feeding test, which normally requires 3 weeks of treatment with classical antidepressants. Our results demonstrate that alpha(2)-adrenoceptors, expressed by progenitor cells, decrease adult hippocampal neurogenesis, while their blockade speeds up antidepressant action, highlighting their importance as targets for faster acting antidepressants
Extraordinarily high biomass benthic community on Southern Ocean seamounts
We describe a previously unknown assemblage of seamount-associated megabenthos that has by far the highest peak biomass reported in the deep-sea outside of vent communities. The assemblage was found at depths of 2–2.5 km on rocky geomorphic features off the southeast coast of Australia, in an area near the Sub-Antarctic Zone characterised by high rates of surface productivity and carbon export to the deep-ocean. These conditions, and the taxa in the assemblage, are widely distributed around the Southern mid-latitudes, suggesting the high-biomass assemblage is also likely to be widespread. The role of this assemblage in regional ecosystem and carbon dynamics and its sensitivities to anthropogenic impacts are unknown. The discovery highlights the lack of information on deep-sea biota worldwide and the potential for unanticipated
impacts of deep-sea exploitation
Potential mitigation and restoration actions in ecosystems impacted by seabed mining
Mining impacts will affect local populations to different degrees. Impacts range from removal of habitats and possible energy sources to pollution and smaller-scale alterations in local habitats that, depending on the degree of disturbance, can lead to extinction of local communities. While there is a shortage or even lack of studies investigating impacts that resemble those caused by actual mining activity, the information available on the potential long-lasting impacts of seabed mining emphasise the need for effective environmental management plans. These plans should include efforts to mitigate deep-sea mining impact such as avoidance, minimisation and potentially restoration actions, to maintain or encourage reinstatement of a resilient ecosystem. A wide range of mitigation and restoration actions for deep-sea ecosystems at risk were addressed. From an ecological point of view, the designation of set-aside areas (refuges) is of utmost importance as it appears to be the most comprehensive and precautionary approach, both for well-known and lesser studied areas. Other actions range from the deployment of artificial substrates to enhance faunal colonisation and survival to habitat recreation, artificial eutrophication, but also spatial and temporal management of mining operations, as well as optimising mining machine construction to minimise plume size on the sea floor, toxicity of the return plume and sediment compression. No single action will suffice to allow an ecosystem to recover, instead combined mitigation/restoration actions need to be considered, which will depend on the specific characteristics of the different mining habitats and the resources hosted (polymetallic sulphides, polymetallic nodules and cobalt-rich ferromanganese crusts). However, there is a lack of practical experience regarding mitigation and restoration actions following mining impacts, which severely hamper their predictability and estimation of their possible effect and success. We propose an extensive list of actions that could be considered as recommendations for best environmental practice. The list is not restricted and, depending on the characteristics of the site, additional actions can be considered. For all actions presented here, further research is necessary to fully encompass their potential and contribution to possible mitigation or restoration of the ecosystem.CT
SFRH/BPD/110278/2015
IF/00029/2014/CP1230/CT0002
UID/MAR/00350/2013
EU Horizon 2020 project Marine Ecosystem Restoration in Changing European Seas (MERCES)
689518
PO ACORES 2020 project
Acores-01-0145-Feder-000054_RECOinfo:eu-repo/semantics/publishedVersio
Real-time visualization of heterotrimeric G protein Gq activation in living cells
Contains fulltext :
97296.pdf (publisher's version ) (Open Access)BACKGROUND: Gq is a heterotrimeric G protein that plays an important role in numerous physiological processes. To delineate the molecular mechanisms and kinetics of signalling through this protein, its activation should be measurable in single living cells. Recently, fluorescence resonance energy transfer (FRET) sensors have been developed for this purpose. RESULTS: In this paper, we describe the development of an improved FRET-based Gq activity sensor that consists of a yellow fluorescent protein (YFP)-tagged Ggamma2 subunit and a Galphaq subunit with an inserted monomeric Turquoise (mTurquoise), the best cyan fluorescent protein variant currently available. This sensor enabled us to determine, for the first time, the kon (2/s) of Gq activation. In addition, we found that the guanine nucleotide exchange factor p63RhoGEF has a profound effect on the number of Gq proteins that become active upon stimulation of endogenous histamine H1 receptors. The sensor was also used to measure ligand-independent activation of the histamine H1 receptor (H1R) upon addition of a hypotonic stimulus. CONCLUSIONS: Our observations reveal that the application of a truncated mTurquoise as donor and a YFP-tagged Ggamma2 as acceptor in FRET-based Gq activity sensors substantially improves their dynamic range. This optimization enables the real-time single cell quantification of Gq signalling dynamics, the influence of accessory proteins and allows future drug screening applications by virtue of its sensitivity
Characterising and Predicting Benthic Biodiversity for Conservation Planning in Deepwater Environments
Understanding patterns of biodiversity in deep sea systems is increasingly important because human activities are extending further into these areas. However, obtaining data is difficult, limiting the ability of science to inform management decisions. We have used three different methods of quantifying biodiversity to describe patterns of biodiversity in an area that includes two marine reserves in deep water off southern Australia. We used biological data collected during a recent survey, combined with extensive physical data to model, predict and map three different attributes of biodiversity: distributions of common species, beta diversity and rank abundance distributions (RAD). The distribution of each of eight common species was unique, although all the species respond to a depth-correlated physical gradient. Changes in composition (beta diversity) were large, even between sites with very similar environmental conditions. Composition at any one site was highly uncertain, and the suite of species changed dramatically both across and down slope. In contrast, the distributions of the RAD components of biodiversity (community abundance, richness, and evenness) were relatively smooth across the study area, suggesting that assemblage structure (i.e. the distribution of abundances of species) is limited, irrespective of species composition. Seamounts had similar biodiversity based on metrics of species presence, beta diversity, total abundance, richness and evenness to the adjacent continental slope in the same depth ranges. These analyses suggest that conservation objectives need to clearly identify which aspects of biodiversity are valued, and employ an appropriate suite of methods to address these aspects, to ensure that conservation goals are met
Increased Expression of the Auxiliary β(2)-subunit of Ventricular L-type Ca(2+) Channels Leads to Single-Channel Activity Characteristic of Heart Failure
BACKGROUND: Increased activity of single ventricular L-type Ca(2+)-channels (L-VDCC) is a hallmark in human heart failure. Recent findings suggest differential modulation by several auxiliary β-subunits as a possible explanation. METHODS AND RESULTS: By molecular and functional analyses of human and murine ventricles, we find that enhanced L-VDCC activity is accompanied by altered expression pattern of auxiliary L-VDCC β-subunit gene products. In HEK293-cells we show differential modulation of single L-VDCC activity by coexpression of several human cardiac β-subunits: Unlike β(1) or β(3) isoforms, β(2a) and β(2b) induce a high-activity channel behavior typical of failing myocytes. In accordance, β(2)-subunit mRNA and protein are up-regulated in failing human myocardium. In a model of heart failure we find that mice overexpressing the human cardiac Ca(V)1.2 also reveal increased single-channel activity and sarcolemmal β(2) expression when entering into the maladaptive stage of heart failure. Interestingly, these animals, when still young and non-failing (“Adaptive Phase”), reveal the opposite phenotype, viz : reduced single-channel activity accompanied by lowered β(2) expression. Additional evidence for the cause-effect relationship between β(2)-subunit expression and single L-VDCC activity is provided by newly engineered, double-transgenic mice bearing both constitutive Ca(V)1.2 and inducible β(2) cardiac overexpression. Here in non-failing hearts induction of β(2)-subunit overexpression mimicked the increase of single L-VDCC activity observed in murine and human chronic heart failure. CONCLUSIONS: Our study presents evidence of the pathobiochemical relevance of β(2)-subunits for the electrophysiological phenotype of cardiac L-VDCC and thus provides an explanation for the single L-VDCC gating observed in human and murine heart failure
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