A protein complex formed by Ustilago maydis effectors is essential for virulence

Ustilago maydis is a biotrophic fungal pathogen that causes smut disease in its host plant maize. During colonization, U. maydis secretes effector proteins to suppress plant defense responses and manipulate the host physiology for its own benefit. The majority of these proteins lack functional annotations and their role in virulence remains to be determined. Transcriptional profiling defined a set of effectors whose expression is linked to the developmental stage in which biotrophy is established. Systematic deletion of these effectors identified three mutants that were no longer able to cause disease. Mutants of these three effectors, named stp2, stp3 and stp4 (stop after penetration), were still able to form appressoria and penetrate the plant, but arrested in the epidermal cell layer. The arrest was accompanied by plant defense responses, including a disruption of the plant plasma membrane surrounding the fungal hyphae. A similar phenotype was observed for the previously described effectors stp1 and pep1. All five effectors are highly conserved among related smut fungi infecting different hosts, suggesting a essential function. Using live cell confocal microscopy, in vitro and in vivo assays, it could be demonstrated that Stp2, Stp3, and Stp4 are secreted by the fungal hyphae, but are not translocated into the plant cell. Confocal microscopy of mCherry fusion strains revealed that all five essential effectors form a speckled pattern on the surface of the biotrophic hyphae. Co-immunoprecipitation/mass spectrometry experiments using each of these essential effectors revealed that Stp1, Stp3, Stp4 and Pep1 form an effector complex. The four complex members did not interact with Stp2 or plant proteins. Recent experiments suggest that Stp2 interacts with at least two other U. maydis effectors, which have a virulence phenotype comparable to stp2 deletion strains. Attempts to visualize the Stp1, Stp3, Stp4 and Pep1 effector complex through bimolecular fluorescence complementation (BiFC) interfered with the complex formation and caused a complete loss of virulence. The subsequent overexpression of two BiFC-fragment tagged complex members in the wild type allele resulted in a dominant negative phenotype. This provides evidence that not only the presence of the individual complex members, but the formation of the complex itself is necessary for a successful colonization. However, using full-length versions of fluorescent proteins enabled the co-localization of complex members and located them in the speckles. Finally, interaction studies in Saccharomyces cerevisiae confirmed the formation of the complex and demonstrated pairwise interactions and subcomplex formations among the complex members. Based on these results, it is proposed that the effector complex forms a structure, whose function is essential for the virulence of U. maydis and could be used as a potential drug target in the future

The Life Experiences of Ten Female Refugees from Iraq and Iran: An Oral History Research Study

This qualitative study about the experiences of 10 religiously persecuted female refugees from Iran (Baha’i) and Iraq (Chaldean) was conducted in both Northern (Bay Area) and Southern (San Diego County) California. The study focused on three periods in their lives: previous experiences in the refugee’s home country prior to resettlement; adaptation to a third country during the resettlement process, especially in regard to experiences with resettlement agencies; and finally, resettlement as refugees in the United States. An oral history methodology was used to conduct the in-depth interviews with the participants. Key findings in the research study included identifying various pull and push factors for leaving their home country and resettling in the United States, such as religious persecution in their homelands as a push factor and the availability of education in the United States as a pull factor. In addition, the findings revealed the hardships the refugees were exposed to while waiting in a third country for processing of their resettlement. Lastly, in regard to the refugees’ experience in the United States, findings showed that the refugees’ identity was more closely tied to their religion (Baha’i/Chaldean) rather than to their nationality and also revealed that some women had a stronger level of independence in the United States than in their home countries

Exploring the capabilities of the Anti-Coincidence Shield of the INTEGRAL spectrometer to study solar flares

INTEGRAL is a hard X-ray/gamma-ray observatory for astrophysics (ESA) covering photon energies from 15 keV to 10 MeV. It was launched in 2002 and since then the BGO detectors of the Anti-Coincidence shield (ACS) of the SPI spectrometer have detected many hard X-ray (HXR) bursts from the Sun, producing lightcurves at photon energies above ~ 100 keV. The spacecraft has a highly elliptical orbit, providing a long uninterrupted observing time (about 90% of the orbital period) with nearly constant background due to the reduction of the crossing time of the Earth's radiation belts. However, due to technical constraints, INTEGRAL cannot point to the Sun and high-energy solar photons are always detected in non-standard observation conditions. To make the data useful for solar studies, we have undertaken a major effort to specify the observing conditions through Monte-Carlo simulations of the response of ACS for several selected flares. We check the performance of the model employed for the Monte-Carlo simulations using RHESSI observations for the same sample of solar flares. We conclude that, despite the fact that INTEGRAL was not designed to perform solar observations, ACS is a useful instrument in solar flare research. In particular, its relatively large effective area allows the determination of good-quality HXR/gamma-ray lightcurves for X- and M-class solar flares and, in some cases, probably also for C-class flares.Comment: 18 pages, 6 figures; Solar Physics 201

High-Thrust in-Space Liquid Propulsion Stage: Storable Propellants

In the frame of a project funded by ESA, a consortium led by Avio in cooperation with Snecma, Cira, and DLR is performing the preliminary design of a High-Thrust in-Space Liquid Propulsion Stage for two different types of manned missions beyond Earth orbit. For these missions, one or two 100 ton stages are to be used to propel a manned vehicle. Three different propellant combinations; LOx/LH2, LOx/CH4 and MON-3/MMH are being compared. The preliminary design of the storable variant (MON-3/MMH) has been performed by DLR. The Aestus II engine with a large nozzle expansion ratio has been chosen as baseline. A first iteration has demonstrated, that it indeed provides the best performance for the storable propellant combination, when considering all engines available today or which may be available in a short- to medium term. The RD-861 K engine has been proposed as alternative to reduce the development duration of the high-thrust stage. Structure analyses and optimisations have converged towards a common bulkhead architecture with a Whipple shield, similar to the one used on the ATV, to protect the main propellant tanks against perforations caused by meteoroids and space debris. The propulsion system has been built around six Aestus II engines equipped with TVC and placed on a circular engine thrust frame. The RCS, the thermal system, and the power system have also been included in the preliminary design, and they have been sized for the most demanding mission. The performance of the high-thrust stage, resulting from the preliminary design, has been assessed for both missions taken into consideration

Potential of Ensemble Copula Coupling for Wind Power Forecasting

With the share of renewable energy sources in the energy system increasing,accurate wind power forecasts are required to ensure a balanced supply anddemand. Wind power is, however, highly dependent on the chaotic weathersystem and other stochastic features. Therefore, probabilistic wind powerforecasts are essential to capture uncertainty in the model parameters and inputfeatures. The weather and wind power forecasts are generally post-processedto eliminate some of the systematic biases in the model and calibrate it topast observations. While this is successfully done for wind power forecasts,the approaches used often ignore the inherent correlations among the weathervariables. The present paper, therefore, extends the previous post-processingstrategies by including Ensemble Copula Coupling (ECC) to restore the de-pendency structures between variables and investigates, whether including thedependency structures changes the optimal post-processing strategy. We findthat the optimal post-processing strategy does not change when including ECCand ECC does not improve the forecast accuracy when the dependency struc-tures are weak. We, therefore, suggest investigating the dependency structuresbefore choosing a post-processing strategy

Analytical uncertainty propagation for multi-period stochastic optimal power flow

The increase in renewable energy sources (RESs), like wind or solar power, results in growing uncertainty also in transmission grids. This affects grid stability through fluctuating energy supply and an increased probability of overloaded lines. One key strategy to cope with this uncertainty is the use of distributed energy storage systems (ESSs). In order to securely operate power systems containing renewables and use storage, optimization models are needed that both handle uncertainty and apply ESSs. This paper introduces a compact dynamic stochastic chance-constrained DC optimal power flow (CC-OPF) model, that minimizes generation costs and includes distributed ESSs. Assuming Gaussian uncertainty, we use affine policies to obtain a tractable, analytically exact reformulation as a second-order cone problem (SOCP). We test the new model on five different IEEE networks with varying sizes of 5, 39, 57, 118 and 300 nodes and include complexity analysis. The results show that the model is computationally efficient and robust with respect to constraint violation risk. The distributed energy storage system leads to more stable operation with flattened generation profiles. Storage absorbed RES uncertainty, and reduced generation cost

A minimally invasive multiple marker approach allows highly efficient detection of meningioma tumors

BACKGROUND: The development of effective frameworks that permit an accurate diagnosis of tumors, especially in their early stages, remains a grand challenge in the field of bioinformatics. Our approach uses statistical learning techniques applied to multiple antigen tumor antigen markers utilizing the immune system as a very sensitive marker of molecular pathological processes. For validation purposes we choose the intracranial meningioma tumors as model system since they occur very frequently, are mostly benign, and are genetically stable. RESULTS: A total of 183 blood samples from 93 meningioma patients (WHO stages I-III) and 90 healthy controls were screened for seroreactivity with a set of 57 meningioma-associated antigens. We tested several established statistical learning methods on the resulting reactivity patterns using 10-fold cross validation. The best performance was achieved by Naïve Bayes Classifiers. With this classification method, our framework, called Minimally Invasive Multiple Marker (MIMM) approach, yielded a specificity of 96.2%, a sensitivity of 84.5%, and an accuracy of 90.3%, the respective area under the ROC curve was 0.957. Detailed analysis revealed that prediction performs particularly well on low-grade (WHO I) tumors, consistent with our goal of early stage tumor detection. For these tumors the best classification result with a specificity of 97.5%, a sensitivity of 91.3%, an accuracy of 95.6%, and an area under the ROC curve of 0.971 was achieved using a set of 12 antigen markers only. This antigen set was detected by a subset selection method based on Mutual Information. Remarkably, our study proves that the inclusion of non-specific antigens, detected not only in tumor but also in normal sera, increases the performance significantly, since non-specific antigens contribute additional diagnostic information. CONCLUSION: Our approach offers the possibility to screen members of risk groups as a matter of routine such that tumors hopefully can be diagnosed immediately after their genesis. The early detection will finally result in a higher cure- and lower morbidity-rate

DO ANKLE STABILIZERS INFLUENCE DYNAMIC STABILITY IN PERSONS WITH FUNCTIONAL ANKLE INSTABILITY?

Ankle sprains are the most common injury in the physically active, and reoccurrence rate is high. Repetitive ankle sprains can cause functional ankle instability (FAI), leading to deficits in balance, strength, and stability. Sports medicine professionals prescribe and administer bracing and taping as extrinsic methods of enhancing ankle stability. What is not clear is how these methods affect neuromuscular control during dynamic movements in persons with FAI. The purpose of this study was to determine the effects of taping and bracing on time to stabilization (TTS), as a measure of dynamic stability, in persons with FAI during two landing tasks