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In optogenetics, rhodopsins were established as light-driven tools to manipulate neuronal activity. However, during long-term photostimulation using channelrhodopsin (ChR), desensitization can reduce effects. Furthermore, requirement for continuous presence of the chromophore all-trans retinal (ATR) in model systems lacking sufficient endogenous concentrations limits its applicability. We tested known, and engineered and characterized new variants of de- and hyperpolarizing rhodopsins in Caenorhabditis elegans. ChR2 variants combined previously described point mutations that may synergize to enable prolonged stimulation. Following brief light pulses ChR2(C128S;H134R) induced muscle activation for minutes or even for hours (‘Quint’: ChR2(C128S;L132C;H134R;D156A;T159C)), thus featuring longer open state lifetime than previously described variants. Furthermore, stability after ATR removal was increased compared to the step-function opsin ChR2(C128S). The double mutants C128S;H134R and H134R;D156C enabled increased effects during repetitive stimulation. We also tested new hyperpolarizers (ACR1, ACR2, ACR1(C102A), ZipACR). Particularly ACR1 and ACR2 showed strong effects in behavioral assays and very large currents with fast kinetics. In sum, we introduce highly light-sensitive optogenetic tools, bypassing previous shortcomings, and thus constituting new tools that feature high effectiveness and fast kinetics, allowing better repetitive stimulation or investigating prolonged neuronal activity states in C. elegans and, possibly, other systems.
The increased susceptibility to infections of neonates is caused by an immaturity of the immune system as a result of both qualitative and quantitative differences between neonatal and adult immune cells. With respect to B cells, neonatal antibody responses are known to be decreased. Accountable for this is an altered composition of the neonatal B cell compartment towards more immature B cells. However, it remains unclear whether the functionality of individual neonatal B cell subsets is altered as well. In the current study we therefore compared phenotypical and functional characteristics of corresponding neonatal and adult B cell subpopulations. No phenotypic differences could be identified with the exception of higher IgM expression in neonatal B cells. Functional analysis revealed differences in proliferation, survival, and B cell receptor signaling. Most importantly, neonatal B cells showed severely impaired class-switch recombination (CSR) to IgG and IgA. This was associated with increased expression of miR-181b in neonatal B cells. Deficiency of miR-181b resulted in increased CSR. With this, our results highlight intrinsic differences that contribute to weaker B cell antibody responses in newborns.
Deutschland und Europa
(2018)
Otmar Issing erörtert die Reaktionen in Deutschland auf die Pläne des französischen Präsidenten Macron aus dessen viel beachteter Rede zur Zukunft Europas an der Pariser Sorbonne. Issing wertet das Ergebnis der Sondierungsgespräche zwischen CDU/CSU und SPD als Abschied von der Vorstellung einer auf Stabilität gerichteten europäischen Gemeinschaft und mahnt an, den einheitlichen Markt und die damit verbundenen Freiheiten nicht durch überzogene Ambitionen zu gefährden und damit zunehmendes Misstrauen gegenüber Europa zu fördern.
Insbesondere in der geplanten Weiterentwicklung des ESM zu einem im Unionsrecht verankerten Europäischen Währungsfonds sieht Issing die Auslieferung der durch den Fonds zur Verfügung gestellten Mittel an eine politische Mehrheit. Zudem führe die Bestellung eines europäischen Finanzministers zur Schaffung einer die Währungsunion ergänzenden Fiskalunion und damit zur Verlagerung finanzpolitischer Kompetenz von der nationalen auf die europäische Ebene. In letzter Konsequenz bedeute dies eine Aufgabe des grundlegenden Prinzips der demokratischen Legitimierung und Kontrolle finanzpolitischer Entscheidungen.
Das Ergebnis der Sondierungsgespräche muss man als Abschied von der Vorstellung einer auf Stabilität gerichteten europäischen Gemeinschaft verstehen. Damit werden die Versprechen gebrochen, die man den Bürgern in Deutschland vor der Einführung des Euros gegeben hat.
Background: Leaf venation traits are important for many research fields such as systematics and evolutionary biology, plant physiology, climate change, and paleoecology. In spite of an increasing demand for vein trait data, studies are often still data-limited because the development of methods that allow rapid generation of large sets of vein data has lagged behind. Recently, non-destructive X-ray technology has proven useful as an alternative to traditional slow and destructive chemical-based methods. Non-destructive techniques more readily allow the use of herbarium specimens, which provide an invaluable but underexploited resource of vein data and related environmental information. The utility of 2D X-ray technology and microfocus X-ray computed tomography, however, has been compromised by insufficient image resolution. Here, we advanced X-ray technology by increasing image resolution and throughput without the application of contrast agents.
Results: For 2D contact microradiography, we developed a method which allowed us to achieve image resolutions of up to 7 µm, i.e. a 3.6-fold increase compared to the industrial standard (25 µm resolution). Vein tracing was further optimized with our image processing standards that were specifically adjusted for different types of leaf structure and the needs of higher imaging throughput. Based on a test dataset, in 91% of the samples the 7 µm approach led to a significant improvement in estimations of minor vein density compared to the industrial standard. Using microfocus X-ray computed tomography, very high-resolution images were obtained from a virtual 3D–2D transformation process, which was superior to that of 3D images.
Conclusions: Our 2D X-ray method with a significantly improved resolution advances rapid non-destructive bulk scanning at a quality that in many cases is sufficient to determine key venation traits. Together with our high-resolution microfocus X-ray computed tomography method, both non-destructive approaches will help in vein trait data mining from museum collections, which provide an underexploited resource of historical and recent data on environmental and evolutionary change. In spite of the significant increase in effective image resolution, a combination of high-throughput and full visibility of the vein network (including the smallest veins and their connectivity) remains challenging, however.
Die Wahrscheinlichkeit einer pathologischen Komplettremission (pCR) bei Brustkrebs nach neoadjuvanter Chemotherapie (NACT) nimmt zu; vor allem in den Subgruppen der tripel-negativen und HER-2-positiven Tumoren. Daher stellt sich die Frage, ob bei einer Komplettremission nach NACT eine operative Therapie der Brust notwendig ist, und ob es einen Vorteil für das onkologische Behandlungsergebnis hat, wenn kein Tumor mehr nachgewiesen werden kann. Ein Verzicht auf die Operation und gegebenenfalls auch auf die Radiotherapie ist jedoch nur auf der Basis einer verlässlichen pCR-Diagnose ohne Operation denkbar. Bildgebende Verfahren erreichen derzeit nicht die nötige Sensitivität und Spezifität, um die Diagnose einer pathologischen Komplettremission sicher zu stellen. Daher sind weitere Studien nötig, um herauszufinden, welche Methode die bestmögliche Evaluation des Tumoransprechens auf NACT erlaubt. Erste vielversprechende Ergebnisse zeigen sich in Studien zu bildgebungsgesteuerten, minimalinvasiven Biopsien nach NACT. Diese evaluieren die Möglichkeit einer pCR-Diagnose vor der Operation und könnten die Grundlage für weitere Studien zu einem möglichen Verzicht auf eine Operation in diesem ausgewählten Kollektiv sein.
The likelihood of pathological complete remission (pCR) of breast cancer following neoadjuvant chemotherapy (NACT) is increasing; most of all in the triple negative and HER2 positive tumour subgroups. The question thus arises whether or not breast surgery is necessary when there is complete remission after NACT, and whether it provides any improvement of the oncological treatment result when tumour is no longer detectable. Avoiding surgery and possibly even radiotherapy would only be conceivable on the basis of a reliable diagnosis of pCR without operating. Current imaging does not achieve the necessary sensitivity and specificity to assure the diagnosis of pathological complete remission. Further studies are therefore required to determine which methods are best able to evaluate tumour response to NACT. Studies on image-guided, minimally invasive biopsies after NACT have delivered first promising results towards diagnosing pCR before surgery and could provide the basis for further studies on the possibility of avoiding surgery in this specific patient collective.
I present a new business cycle model in which decision making follows a simple mental process motivated by neuroeconomics. Decision makers first compute the value of two different options and then choose the option that offers the highest value, but with errors. The resulting model is highly tractable and intuitive. A demand function in level replaces the traditional Euler equation. As a result, even liquid consumers can have a large marginal propensity to consume. The interest rate affects consumption through the cost of borrowing and not through intertemporal substitution. I discuss the implications for stimulus policies.
This paper analyses whether the post-crisis regulatory reforms developed by global-standard-setting bodies have created appropriate incentives for different types of market participants to centrally clear Over-The-Counter (OTC) derivative contracts. Beyond documenting the observed facts, we analyze four main drivers for the decision to clear: 1) the liquidity and riskiness of the reference entity; 2) the credit risk of the counterparty; 3) the clearing member’s portfolio net exposure with the Central Counterparty Clearing House (CCP) and 4) post trade transparency. We use confidential European trade repository data on single-name Sovereign Credit Derivative Swap (CDS) transactions, and show that for all the transactions reported in 2016 on Italian, German and French Sovereign CDS 48% were centrally cleared, 42% were not cleared despite being eligible for central clearing, while 9% of the contracts were not clearable because they did not satisfy certain CCP clearing criteria. However, there is a large difference between CCP clearing members that clear about 53% of their transactions and non-clearing members, even those that are subject to counterparty risk capital requirements, that almost never clear their trades. Moreover, we find that diverse factors explain clearing members’ decision to clear different CDS contracts: for Italian CDS, counterparty credit risk exposures matter most for the decision to clear, while for French and German CDS, margin costs are the most important factor for the decision. Clearing members use clearing to reduce their exposures to the CCP and largely clear contracts when at least one of the traders has a high counterparty credit risk.
The longevity of the population in the Okinawa Islands of Japan has been ascribed to genetic factors and the traditional Okinawa cuisine, which is low in calories and high in plant content. This diet includes shell ginger (Alpinia zerumbet (Pers.) B.L. Burtt & R.M. Sm) of the ginger family (Zingiberaceae). Due to its local popularity, Alpinia zerumbet has become the subject of a good deal of study at the University of the Ryukyus in Okinawa. Personal local experience and review of the literature now suggest that culinary shell ginger may contribute to longevity among the population in Okinawa. This is supported by its abundant phytochemical content, with antioxidant and anti-obesity properties. The major bioactive phytochemicals are dihydro-5,6-dehydrokawain (DDK; 80–410 mg g−1 fresh weight), 5,6-dehydrokawain (DK; ≤100 mg g−1), and essential oils, phenols, phenolic acids, and fatty acids (≤150 mg g−1 each). Further, Alpinia zerumbet extends the lifespan in animals by 22.6%. In conclusion, culinary shell ginger may significantly contribute to human longevity in Okinawa.
The blue light-dependent interaction between the proteins iLID and Nano allows recruiting and patterning proteins on GUV membranes, which thereby capture key features of patterns observed in nature. This photoswitchable protein interaction provides non-invasive, reversible and dynamic control over protein patterns of different sizes with high specificity and spatiotemporal resolution.