562 research outputs found
NeurovaskulÀre VerÀnderungen nach fokaler zerebraler IschÀmie in MÀusen mit Alzheimer-artigen Merkmalen
Alzheimer-Demenz als hĂ€ufigste Demenzform wird vorrangig als eigenstĂ€ndige neurodegenerative Erkrankung gesehen, teilt jedoch mit dem akuten Schlaganfall einige Risikofaktoren. Das Alter scheint dabei der zentrale Faktor zu sein, der die Ăberlappung beider Erkrankungen erklĂ€rt, da sowohl kardiovaskulĂ€re Risikofaktoren wie arterielle Hypertonie, HypercholesterinĂ€mie und Diabetes als auch die HĂ€ufigkeit der Alzheimerschen Erkrankung und der zerebralen IschĂ€mie mit steigender Lebenszeit zunehmen. Das steigende Interesse an der genauen AufklĂ€rung der Pathomechanismen beider Erkrankungen, kann mit dem demografischen Wandel begrĂŒndet werden, aus dem die erhebliche absolute Zunahme beider Erkrankungen resultiert und ein enormer volkswirtschaftlicher Kostenaufwand erwĂ€chst.
\\Experimentelle Studien sowie klinische Beobachtungen lassen vermuten, dass es einen kausalen Zusammenhang zwischen der Alzheimerschen Erkrankung und dem Schlaganfall gibt. Es wurde gezeigt, dass Patienten mit einer zerebralen IschĂ€mie in der Anamnese ein erhöhtes Risiko haben an der Alzheimerschen Demenz zu erkranken. Zudem wurde nachgewiesen, dass chronische Hypertonie und experimentelle Schlaganfall-Induktion Alzheimer-artige VerĂ€nderungen verursachen, wie z.B. höhere Konzentration von APP und Tau-Phosphorylierung. Gleichsinnig dazu haben Alzheimer-Patienten zum einen ein erhöhtes Risiko fĂŒr ein ischĂ€misches Ereignis, zum anderen ist das Auftreten eines Schlaganfalls bei Alzheimer-Patienten mit einer schlechteren Prognose vergesellschaftet. Es wurde postuliert, dass -Amyloid und IschĂ€mie bei gemeinsamem Auftreten schlechtere Konsequenzen hervorrufen, als wenn diese Faktoren einzeln vorkommen.
\\Im Tiermodell konnte gezeigt werden, dass ischĂ€mische Ereignisse, insbesondere mildere Formen, in Anwesenheit von hohen Konzentrationen an -Amyloid gröĂere Infarktvolumina, eine fulminantere EntzĂŒndungsreaktion und einen schwereren GedĂ€chtnisverlust verursachen im Vergleich zum alleinigen Auftreten von IschĂ€mie oder -Amyloid. Die offensichtliche wechselseitige Beeinflussung der pathologischen VerĂ€nderungen erschwert die Konzipierung erfolgreicher Behandlungsstrategien. Daher wandten sich verschiedene Forschungsgruppen ab von den Angriffspunkten an typischen Merkmalen der Alzheimerschen Erkrankung (wie -Amyloid, Tau-Hyperphosphorylierung und cholinerge Dysfunktion) hin zu einem komplexeren Denkansatz mit BerĂŒcksichtigung von Neuronen in Assoziation mit GefĂ€Ăstrukturen sowie Astro- und Mikroglia, zusammengefasst als neurovaskulĂ€re Einheit (NVU). Das Verstehen der komplexen neurovaskulĂ€ren Pathologie im Alzheimer-IschĂ€mie-Kontext sollte zur Entwicklung neuerer, spezifischer Behandlungsstrategien fĂŒhren.
\\Die vorliegende Studie fokussierte dabei auf cholinerge, Cholinazetyltransferase (ChAT)-immunpositive, und katecholaminerge, Tyrosinhydroxylase (TH)-immunpositive, Nervenfasern in Assoziation mit endothelialen GefĂ€Ăstrukturen, um die NVU im Alzheimer-Gehirn mit begleitendem Schlaganfall zu untersuchen. Ein Schwerpunkt lag dabei auf der Analyse der ChAT als dem Enzym, dessen AktivitĂ€tsverlust in Zusammenhang mit der altersabhĂ€ngigen Degeneration von cholinergen Neuronen im basalen Vorderhirn steht. Die Degeneration des cholinergen Systems ist nachweislich involviert in die Progression der Alzheimerschen Erkrankung sowie mitverantwortlich fĂŒr einen kognitiven Funktionsverlust, bedingt durch AÎČ-Vorkommen und Tau-Phosphorylierung.
\\FĂŒr die vorliegende Studie wurde in Wildtyp-MĂ€usen und triple-transgenen (3xTg) MĂ€usen verschiedener Altersgruppen (3 und 12 Monate) eine unilaterale fokale zerebrale IschĂ€mie induziert. Die 3xTg-MĂ€use vereinigen zwei menschliche Transgene (Amyloid-PrĂ€kursorprotein und Tau) und sind homozygot fĂŒr das Knock-in-Konstrukt PrĂ€senilin. ZusĂ€tzlich wurden drei 2 Jahre alte 3xTg-MĂ€use untersucht um altersabhĂ€ngige Alzheimer-artige Merkmale nachzuweisen.
\\Histochemische Analysen dienten zum Vergleich der neuronalen und vaskulĂ€ren Komponenten der NVU sowie der Alzheimer-spezifischen Merkmale. Fluoreszenzmarkierungen bestĂ€tigten die Existenz Alzheimer-typischer Charakteristika wie -Amyloid-Vorkommen und Phospho-Tau zusammen mit glialen Reaktionen und morphologisch verĂ€ndertem Endothel, das mit \textit{Solanum tuberosum} Lektin (STL, Kartoffellektin) dargestellt wurde. Neben deutlichen morphologischen VerĂ€nderungen der GefĂ€Ăstrukturen kam es 24 Stunden nach IschĂ€mie-Induktion zu einem drastischen RĂŒckgang der ImmunreaktivitĂ€t fĂŒr TH und ChAT als neuronalen Komponenten der NVU, vor allem im ischĂ€mie-betroffenen Striatum aber auch in ischĂ€miefernen Arealen wie der ischĂ€mischen Grenzzone und dem ipsilateralen Neokortex. Aufgrund von Korrelationsanalysen, die eine gleichsinnige Degeneration des cholinergen Systems und des Endothels gezeigt haben, kann man von gleichzeitigen VerĂ€nderungen multipler Zelltypen innerhalb der NVU im IschĂ€mie-betroffenen Gehirn mit Alzheimer-PhĂ€notyp ausgehen. AusgeprĂ€gter erschien der beschriebene Effekt auf cholinerge Komponenten jĂŒngerer MĂ€usen zuzutreffen.
Die vorgelegten Ergebnisse unterstreichen das komplexe Zusammenspiel der verschiedenen Zelltypen innerhalb der NVU im Alzheimer-Gehirn mit ischĂ€mischen VerĂ€nderungen, einschlieĂlich der VerĂ€nderungen des cholinergen Systems in Verbindung mit vaskulĂ€ren Pathologien. Daher sollten neue Behandlungsstrategien neben bereits etablierten AnsĂ€tzen gegen neuronale Degeneration und Tau-Phosphorylierung auch auf zellulĂ€rer Ebene eingreifen, z.B. durch Stabilisierung der IntegritĂ€t von endothelialen und glialen Elementen, eingreifen. Derartige Strategien könnten die Krankheitsentwicklung verzögern und das Krankheitsbild mildern
Preventing Conflicts in Sharing Communities as a Means of Promoting Sustainability
The sharing economy is a new promising trend with many positive outcomes on society and
the environment, as it provides potential for sustainable solutions due to the reduction of resource
consumption and less waste. However, research and practice show that sharing comes with its
own share of problems. People often act selfishly, and in worst-case scenarios try to take advantage
of others without contributing to the shared good. To achieve the higher goal of sustainability,
it is important that conflicts in the sharing economy are prevented, and a setting is achieved that
allows people to easily behave in a cooperative and sustainable way. The present research examines
which conflicts emerge in sharing communities (study 1) and community gardens in particular
(study 2), and whether regulation can prevent conflicts in large groups. Two exploratory studies were
conducted. First, a qualitative study with consumers and non-consumers of the sharing economy
revealed that regulatory systems are perceived as important for preventing the exploitation of other
community members, but also that cooperation should not be enforced with strict controls and
punishment. Rather, problems should be discussed in a democratic group setting, rules and goals
should be set up together, and trust should be built. Second, a questionnaire study with community
gardeners in Austria confirmed these results, and showed that trust is related to less conflict in
community gardens, while harsh forms of regulation are related to a potential for greater conflict.
Additionally, the results indicate that soft forms of regulation are related to fewer relationship and task
conflicts, better conflict resolutions, a high sense of community, and greater trust in the community.
We then discuss how these findings can be used to regulate sharing economy activities and give
limitations and directions for future studies
The Influence of Regulation on Trust and Risk Preference in Sharing Communities
Sharing within communities has gained popularity in recent years. However, taking part
in a community also comes with a certain amount of risk. This perceived amount
of risk can be contained by regulations within a community as well as by potential
participantsâ trust in the community and the other members. We argue for a relation
between regulation and the willingness to take the risk of joining a sharing community
with trust as a mediator. Thereby, we distinguish between two kinds of regulation (soft
and harsh regulation) and two kinds of trust (implicit and reason-based trust) on two
different levels (vertical and horizontal trust). In one laboratory and one online experiment
with 432 participants overall, we found that the compound of high soft and low harsh
regulation increases participantsâ willingness to take the risk of participation and that the
effect of soft regulation is mediated mainly by vertical and horizontal reason-based trust.
Based on our results, we encourage sharing communities to count on soft regulation in
order to increase potential membersâ trust in the community and therefore take the risk
to participate
An Intracellular Nanotrap Redirects Proteins and Organelles in Live Bacteria
Owing to their small size and enhanced stability, nanobodies derived from camelids have previously been used for the construction of intracellular "nanotraps," which enable redirection and manipulation of green fluorescent protein (GFP)-tagged targets within living plant and animal cells. By taking advantage of intracellular compartmentalization in the magnetic bacterium Magnetospirillum gryphiswaldense, we demonstrate that proteins and even entire organelles can be retargeted also within prokaryotic cells by versatile nanotrap technology. Expression of multivalent GFP-binding nanobodies on magnetosomes ectopically recruited the chemotaxis protein CheW(1)-GFP from polar chemoreceptor clusters to the midcell, resulting in a gradual knockdown of aerotaxis. Conversely, entire magnetosome chains could be redirected from the midcell and tethered to one of the cell poles. Similar approaches could potentially be used for building synthetic cellular structures and targeted protein knockdowns in other bacteria. IMPORTANCE Intrabodies are commonly used in eukaryotic systems for intracellular analysis and manipulation of proteins within distinct subcellular compartments. In particular, so-called nanobodies have great potential for synthetic biology approaches because they can be expressed easily in heterologous hosts and actively interact with intracellular targets, for instance, by the construction of intracellular "nanotraps" in living animal and plant cells. Although prokaryotic cells also exhibit a considerable degree of intracellular organization, there are few tools available equivalent to the well-established methods used in eukaryotes. Here, we demonstrate the ectopic retargeting and depletion of polar membrane proteins and entire organelles to distinct compartments in a magnetotactic bacterium, resulting in a gradual knockdown of magneto-aerotaxis. This intracellular nanotrap approach has the potential to be applied in other bacteria for building synthetic cellular structures, manipulating protein function, and creating gradual targeted knockdowns. Our findings provide a proof of principle for the universal use of fluorescently tagged proteins as targets for nanotraps to fulfill these tasks
Enhancement of the efficiency of non-viral gene delivery by application of pulsed magnetic field
New approaches to increase the efficiency of non-viral gene delivery are still required. Here we report a simple approach that enhances gene delivery using permanent and pulsating magnetic fields. DNA plasmids and novel DNA fragments (PCR products) containing sequence encoding for green fluorescent protein were coupled to polyethylenimine coated superparamagnetic nanoparticles (SPIONs). The complexes were added to cells that were subsequently exposed to permanent and pulsating magnetic fields. Presence of these magnetic fields significantly increased the transfection efficiency 40 times more than in cells not exposed to the magnetic field. The transfection efficiency was highest when the nanoparticles were sedimented on the permanent magnet before the application of the pulsating field, both for small (50 nm) and large (200-250 nm) nanoparticles. The highly efficient gene transfer already within 5 min shows that this technique is a powerful tool for future in vivo studies, where rapid gene delivery is required before systemic clearance or filtration of the gene vectors occur
Enhancement of the efficiency of non-viral gene delivery by application of pulsed magnetic field
New approaches to increase the efficiency of non-viral gene delivery are still required. Here we report a simple approach that enhances gene delivery using permanent and pulsating magnetic fields. DNA plasmids and novel DNA fragments (PCR products) containing sequence encoding for green fluorescent protein were coupled to polyethylenimine coated superparamagnetic nanoparticles (SPIONs). The complexes were added to cells that were subsequently exposed to permanent and pulsating magnetic fields. Presence of these magnetic fields significantly increased the transfection efficiency 40 times more than in cells not exposed to the magnetic field. The transfection efficiency was highest when the nanoparticles were sedimented on the permanent magnet before the application of the pulsating field, both for small (50 nm) and large (200â250 nm) nanoparticles. The highly efficient gene transfer already within 5 min shows that this technique is a powerful tool for future in vivo studies, where rapid gene delivery is required before systemic clearance or filtration of the gene vectors occurs
PINK1-Interacting Proteins: Proteomic Analysis of Overexpressed PINK1
Recent publications suggest that the Parkinson's disease- (PD-) related PINK1/Parkin pathway promotes elimination of dysfunctional mitochondria by autophagy. We used tandem affinity purification (TAP), SDS-PAGE, and mass spectrometry as a first step towards identification of possible substrates for PINK1. The cellular abundance of selected identified interactors was investigated by Western blotting. Furthermore, one candidate gene was sequenced in 46 patients with atypical PD. In addition to two known binding partners (HSP90, CDC37), 12 proteins were identified using the TAP assay; four of which are mitochondrially localized (GRP75, HSP60, LRPPRC, and TUFM). Western blot analysis showed no differences in cellular abundance of these proteins comparing PINK1 mutant and control fibroblasts. When sequencing LRPPRC, four exonic synonymous changes and 20 polymorphisms in noncoding regions were detected. Our study provides a list of putative PINK1 binding partners, confirming previously described interactions, but also introducing novel mitochondrial proteins as potential components of the PINK1/Parkin mitophagy pathway
Potential Repercussions of Offshore Wind Energy Development in the Northeast United States for the Atlantic Surfclam Survey and Population Assessment
The Atlantic surfclam Spisula solidissima fishery, which spans the U.S. Northeast continental shelf, is among the most exposed to offshore wind energy development impacts because of the overlap of fishing grounds with wind energy lease areas, the hydraulic dredges used by the fishing vessels, and the location of vessel home ports relative to the fishing grounds. The Atlantic surfclam federal assessment survey is conducted using a commercial fishing vessel in locations that overlap with the offshore wind energy development. Once wind energy turbines, cables, and scour protection are installed, survey operations within wind energy lease areas may be curtailed or eliminated due to limits on vessel access, safety requirements, and assessment survey protocols. The impact of excluding the federal assessment survey from wind energy lease areas was investigated using a spatially explicit, agent-based modeling framework that integrates Atlantic surfclam stock biology, fishery captain and fleet behavior, and federal assessment survey and management decisions. Simulations were designed to compare assessment estimates of spawning stock biomass (SSB) and fishing mortality (F) for scenarios that excluded the survey from (1) wind energy lease areas or (2) wind energy lease areas and potential wind energy lease areas (âcall areasâ). For the most restricted scenario, the simulated stock assessment estimated 17% lower SSB relative to an unrestricted survey, placing it below the SSB target. The simulated F increased by 7% but was still less than the accepted F threshold. Changes in biological reference points were driven by the inability to access the Atlantic surfclam biomass within the wind energy lease areas. Deviations in reference points reflected the proportion of the population excluded from the survey. Excluding the Atlantic surfclam assessment surveys from the regions designated for offshore wind development can alter long-term stock assessments by increasing uncertainty in metrics that are used to set fishing quotas
The Atlantic Surfclam Fishery and Offshore Wind Energy Development: 1. Model Development and Verification
Competing pressures imposed by climate-related warming and offshore development have created a need for quantitative approaches that anticipate fisheries responses to these challenges. This study used a spatially explicit, ecological-economic agent-based model integrating dynamics associated with Atlantic surfclam stock biology, decision-making behavior of fishing vessel captains, and fishing fleet behavior to simulate stock biomass, and fishing vessel catch, effort and landings. Simulations were implemented using contemporary Atlantic surfclam stock distributions and characteristics of the surfclam fishing fleet. Simulated distribution of fishable surfclam biomass was determined by a spatially varying mortality rate, fishing by the fleet was controlled by captain decisions based on previous knowledge, information sharing, and the ability to search and find fishing grounds. Quantitative and qualitative evaluation of simulation results showed that this modeling approach sufficiently represents Atlantic surfclam fishery dynamics. A fishing simulation showed that the captain\u27s decision-making and stock knowledge, and the distribution of fishing grounds relative to home ports controlled the landed catch. The approach used herein serves as the basis for future studies examining response of the Atlantic surfclam fishery to a nexus of simultaneous, complex natural and anthropogenic pressures, and provides a framework for similar models for other resources facing similar pressures
The Atlantic surfclam fishery and offshore wind energy development: 1. Model development and verification
Competing pressures imposed by climate-related warming and offshore development have created a need for quantitative approaches that anticipate fisheries responses to these challenges. This study used a spatially explicit, ecological-economic agent-based model integrating dynamics associated with Atlantic surfclam stock biology, decision-making behavior of fishing vessel captains, and fishing fleet behavior to simulate stock biomass, and fishing vessel catch, effort and landings. Simulations were implemented using contemporary Atlantic surfclam stock distributions and characteristics of the surfclam fishing fleet. Simulated distribution of fishable surfclam biomass was determined by a spatially varying mortality rate, fishing by the fleet was controlled by captain decisions based on previous knowledge, information sharing, and the ability to search and find fishing grounds. Quantitative and qualitative evaluation of simulation results showed that this modeling approach sufficiently represents Atlantic surfclam fishery dynamics. A fishing simulation showed that the captainâs decision-making and stock knowledge, and the distribution of fishing grounds relative to home ports controlled the landed catch. The approach used herein serves as the basis for future studies examining response of the Atlantic surfclam fishery to a nexus of simultaneous, complex natural and anthropogenic pressures, and provides a framework for similar models for other resources facing similar pressures
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