Plasma Membrane Organization of Epidermal Growth Factor Receptor in Resting and Ligand-Bound States

AbstractThe spatial arrangement of the epidermal growth factor receptor (EGFR) on the cellular plasma membrane is one of the prime factors that control its downstream signaling pathways and related functions. However, the molecular organization, which spans the scale from nanometers to micrometer-size clusters, has not been resolved in detail, mainly due to a lack of techniques with the required spatiotemporal resolution. Therefore, we used imaging total internal reflection-fluorescence correlation spectroscopy to investigate EGFR dynamics on live CHO-K1 plasma membranes in resting and ligand-bound states. In combination with the fluorescence correlation spectroscopy diffusion law, this provides information on the subresolution organization of EGFR on cell membranes. We found that overall EGFR organization is sensitive to both cholesterol and the actin cytoskeleton. EGFR in the resting state is partly trapped in cholesterol-containing domains, whereas another fraction exhibits cholesterol independent trapping on the membrane. Disruption of the cytoskeleton leads to a broader range of EGFR diffusion coefficients and a reduction of hop diffusion. In the ligand-bound state we found a dose-dependent behavior. At 10 ng/mL EGF the EGFR is endocytosed and recycled to the membrane, whereas diffusion and organization do not change significantly. At 100 ng/mL EGF the EGFR forms clusters, which are subsequently internalized, whereas outside the clusters diffusivity increases and the organization of the receptor remains unchanged. After disruption of cholesterol-containing domains or actin cytoskeleton, EGF induces microscopic EGFR clusters on the membrane and endocytosis is inhibited

Impacts of climate variability and climate change on renewable power generation

Anthropogenic climate change represents a major risk for human civilization and its mitigation requires reductions of greenhouse gas emissions. To stay consistent with the long-term temperature targets of international climate policy, global greenhouse gas emissions have to reach zero within a few decades. Such a dramatic transition towards sustainability in all sectors of human activity requires the decarbonization of power generation at an early stage. In absence of other viable technology choices and given the significant cost declines, renewable power generation forms the backbone of the decarbonization. In contrast to thermal power plants, most renewables are not dispatchable but their generation dynamics are governed by the weather. This dissertation adds to the quantification of impacts of climate variability on wind power generation on different time scales. In particular, it shows that inter-annual wind power generation variability already today has a strong influence on congestion management costs in Germany. Understanding this variability as a normal system feature helps to prevent short-sighted reactions in legislation and power system design. Moreover, it is shown that relevant multi-decadal wind power generation variability exists. Owing to timescales of up to 50 years, these modes are not sufficiently sampled in any modern reanalysis (e.g., MERRA2 or ERA-Interim), which currently cover around 40 years. Consequently, power system assessments based on modern reanalyses may be flawed and should be complemented by multi-decadal assessments. In this context, I also show that 20th century reanalyses (ERA-20C, CERA20C, 20CRv2c) disagree strongly and systematically with respect to long-term wind speed trends. The discrepancy can be traced back to marine wind speed observations which also feature strong upward wind trends that are likely due to an evolving measurement technique. As a consequence, 20th century reanalyses should be employed with care and cross-validation of results is recommended. Due to their weather dependency, renewables are potentially vulnerable to climate change. Indeed, I show that the benefits of large-scale transmission infrastructure in Europe shrink under strong climate change (RCP8.5). The effect is robust across a five member EUROCORDEX ensemble and can be solidified in a larger CMIP5 ensemble. It is rooted in more homogeneous wind conditions over Europe that lead to less smoothing effects via large scale spatial integration. Lastly, the debate around negative emission technologies to enlarge the carbon budget currently focuses on land-based approaches such as Bioenergy with Carbon Capture and Storage. Based on a schematic integration of Direct Air Capture (DAC), we show that its flexibility complements renewable generation variability and can help to integrate large shares of renewables

Sub-national projection methods for Scotland and Scottish areas: a review and recommendations

This report responds to a request for advice by National Records of Scotland (NRS) on how to adapt and improve the methodology used for the Scotland Sub-National Population Projections (SNPP). The 2014- based Scotland SNPP are currently being prepared

Climate information websites: an evolving landscape

The climate change agenda is populated by actors and agencies with different objectives, values, and motivations, yet many seek decision scale climate information to inform policy and adaptation responses. A central element of this network of activity is the climate information website (CIW) that has seen a rapid and organic growth, yet with variable content and quality, and unfettered by any code of practice. This builds an ethical–epistemic dilemma that warrants assessment as the presence of CIWs contribute to real-world consequences and commitment. This study considers the context of CIW growth, and reviews a representative sample of CIWs to draw out key issues for consideration in CIW development. We assess content, function, and use-case value through a dual approach of a typology and user experience narratives to evaluate the general efficacy of a CIW. The typology reveals strong contrasts in content, complicated interfaces, and an overload of choice making it difficult to converge on a stable outcome. The narratives capture user experience and highlight barriers that include navigation difficulties, jargon laden content, minimal or opaque guidance, and inferred information without context about uncertainty and limits to skill. This illuminates four concerns: (1) the ethics of information provision in a context of real-world consequences; (2) interfaces that present barriers to achieving robust solutions; (3) weak capacity of both users and providers to identify information of value from the multimodel and multimethod data; and (4) inclusion of data that infer skill. Nonetheless, results provide a positive indication of a community of practice that is still maturing. WIREs Clim Change 2017, 8:e470. doi: 10.1002/wcc.470. For further resources related to this article, please visit the WIREs website

Membrane destabilization by monomeric hIAPP observed by imaging fluorescence correlation spectroscopy

Monomeric hIAPP significantly destabilizes both model and live cell membranes by increasing membrane fluidity. This interaction with membranes happens via carpet formation followed by lipid extraction in a concentration dependent manner and thus we propose that hIAPP aggregation prior to membrane interaction may not be necessary for its cytotoxicity

Sicherung der Daseinsvorsorge in ländlichen Grenzräumen - eine Untersuchung am Beispiel der Großregion

Die Sicherung der Daseinsvorsorge in ländlichen Räumen steht vor dem Hintergrund des demografischen Wandels und der damit verbundenen Schrumpfung und Alterung der Bevölkerung vor großen Herausforderungen. Ländliche Grenzräume stellen hierbei aufgrund ihrer räumlichen Lage eine besondere Situation dar und haben zusätzliche Herausforderungen zu meistern, wenn sie mit ihren Nachbarn im Bereich der Daseinsvorsorge kooperieren möchten. Der Artikel untersucht die grenzüberschreitende Zusammenarbeit im Bereich der Daseinsvorsorge in ländlichen Teilräumen der Großregion. Als Untersuchungsgebiet dienen die deutschen Gebietskörperschaften an der deutsch-französischen Grenze innerhalb der Großregion. Anhand der Auseinandersetzung mit den Zuständigkeiten und Verständnissen der Daseinsvorsorge in Deutschland und Frankreich, einer knappen Bestandsaufnahme der Daseinsvorsorgebereiche Bildung und Gesundheit, einer schriftlichen Befragung der deutschen Gebietskörperschaften im deutsch-französischen Grenzraum sowie anhand von Projektbeispielen (bspw. INTERREG A - Projekten), sollen Erfolge, Hemmnisse und Chancen grenzüberschreitender Ansätze aufgezeigt werden.In the context of demographic change and the associated shrinking and aging of the population, the safeguarding of services of general interest in rural areas faces great challenges. Rural border areas find themselves in a special situation due to their spatial position, and must overcome additional challenges if they want to cooperate with their neighbours in the provision of services of general interest. The paper investigates cross-border cooperation in the field of services of general interest in rural sub-spaces of the Greater Region. Within the Greater Region, the German regional corporations on the German-French border make up the study area. An analysis of the responsibilities for and understandings of services of general interest in Germany and France, a concise inventory of the education and health services, a written survey of German regional corporations in the German-French border area, and case studies of projects (e.g. INTERREG A projects) are used to demonstrate the successes, problems and opportunities of cross-border approaches

Single microcolony diffusion analysis in Pseudomonas aeruginosa biofilms

© 2019, The Author(s). The influence of the biofilm matrix on molecular diffusion is commonly hypothesized to be responsible for emergent characteristics of biofilms such as nutrient trapping, signal accumulation and antibiotic tolerance. Hence quantifying the molecular diffusion coefficient is important to determine whether there is an influence of biofilm microenvironment on the mobility of molecules. Here, we use single plane illumination microscopy fluorescence correlation spectroscopy (SPIM-FCS) to obtain 3D diffusion coefficient maps with micrometre spatial and millisecond temporal resolution of entire Pseudomonas aeruginosa microcolonies. We probed how molecular properties such as size and charge as well as biofilm properties such as microcolony size and depth influence diffusion of fluorescently labelled dextrans inside biofilms. The 2 MDa dextran showed uneven penetration and a reduction in diffusion coefficient suggesting that the biofilm acts as a molecular sieve. Its diffusion coefficient was negatively correlated with the size of the microcolony. Positively charged dextran molecules and positively charged antibiotic tobramycin preferentially partitioned into the biofilm and remained mobile inside the microcolony, albeit with a reduced diffusion coefficient. Lastly, we measured changes of diffusion upon induction of dispersal and detected an increase in diffusion coefficient inside the biofilm before any loss of biomass. Thus, the change in diffusion is a proxy to detect early stages of dispersal. Our work shows that 3D diffusion maps are very sensitive to physiological changes in biofilms, viz. dispersal. However, this study also shows that diffusion, as mediated by the biofilm matrix, does not account for the high level of antibiotic tolerance associated with biofilms

Breathlessness and sexual activity in older adults: The Australian Longitudinal Study of Ageing

© 2018 The Author(s). Sexual activity is important to older adults (65 +). Breathlessness affects about 25% of older adults but impact on sexual activity is unknown. We evaluated the relationships between breathlessness and sexual inactivity and self-reported health among older community-dwelling adults in the Australian Longitudinal Study of Ageing. Associations between self-reported breathlessness (hurrying on level ground or walking up a slight hill) at baseline, self-reported sexual activity, overall health and health compared to people of the same age were explored using logistic regression at baseline and 2 years, adjusted for potential confounders (age, sex, marital status, smoking status and co-morbidities). Of 798 participants (mean age 76.4 years [SD, 5.8] 65 to 103; 53% men, 73% married), 688 (86.2%) had 2-year follow-up data. People with breathlessness had higher prevalence and duration of sexual inactivity (77.7% vs. 65.6%; p < 0.001; 12 [IQR, 5-17] vs. 9.5 [IQR, 5-16] years; p = 0.043). Breathlessness was associated with more sexual inactivity, (adjusted OR 1.75; [95% CI] 1.24-2.45), worse health (adjusted OR 2.02; 1.53-2.67) and worse health compared to peers (adjusted OR 1.72; 1.25-2.38). Baseline breathlessness did not predict more sexual inactivity at 2 years. In conclusion, breathlessness contributes to sexual inactivity and worse perceived health in older adults, which calls for improved assessment and management