The Interaction Between Endopolygalacturonase From Fusarium Moniliforme and PGIP from Phaseolus Vulgaris Studied by Surface Plasmon Resonance and Mass Spectrometry

A combination of surface plasmon resonance (SPR) and matrix-assisted laser-desorptionionization- time-of-flight mass spectrometry (MALDI-TOF-MS) was used to study the interaction between endopolygalacturonase (PG) from Fusarium moniliforme and a polygalacturonase-inhibiting protein (PGIP) from Phaseolus vulgaris. PG hydrolyses the homogalacturonan of the plant cell wall and is considered an important pathogenicity factor of many fungi. PGIP is a specific inhibitor of fungal PGs and is thought to be involved in plant defence against phytopathogenic fungi. SPR was used either to study the effect of the PG glycosylation on the formation of the complex with PGIP, and as a sensitive affinity capture of an interacting peptide from a mixture of PG fragments obtained by limited proteolysis. Mass spectrometry allowed to characterise the interacting peptide eluted from the sensor surface

Suppression of X-rays during an optical outburst of the helium dwarf nova KL Dra

KL Dra is a helium accreting AM CVn binary system with an orbital period close to 25 mins. Approximately every 60 days there is a 4 mag optical outburst lasting ~10 days. We present the most sensitive X-ray observations made of an AM CVn system during an outburst cycle. A series of eight observations were made using XMM-Newton which started shortly after the onset of an optical outburst. We find that X-rays are suppressed during the optical outburst. There is some evidence for a spectral evolution of the X-ray spectrum during the course of the outburst. A periodic modulation is seen in the UV data at three epochs -- this is a signature of the binary orbital or the super-hump period. The temperature of the X-ray emitting plasma is cooler compared to dwarf novae, which may suggest a wind is the origin of a significant fraction of the X-ray flux.Comment: Accepted by MNRA

Softer Junctions Can Result In Stiffer Gels: Associative Polymer Gels With Crystalline And Semicrystalline Domains

The ability to create synthetic materials that mimic the structural and mechanical properties of soft biological tissues remains a significant challenge. In this presentation, we discuss rheology and structural studies of poly(lactide)-poly(ethylene oxide)-poly(lactide) (PLA-PEO-PLA) triblock copolymer gels with various ratios of L-lactide and D-lactide in the PLA blocks (Figure 1). These materials form associative micellar gels in water, and previous work has shown that stereoregular triblocks with a L/D ratio of 100/0 form much stiffer gels than triblocks with a 50/50 L/D ratio. Our systems display an unexpected maximum in the storage modulus, G’, of the hydrogels at intermediate L/D ratio. The impact of stereochemistry on the rheology is very striking; gels with an L/D ratio of 85/15 have storage moduli that are ~1-2 orders of magnitude higher than hydrogels with L/D ratios of 100/0. No stereocomplexation is observed in the gels, although PLLA crystals are found for gels with L/D ratios of 95/5 and 90/10, and SANS results show a decrease in the intermicellar spacing for intermediate L/D ratios. We expect the dominant contribution to the elasticity of the gels to be intermicellar brdging chains and attribute the rheology to a competition between an increase in the time for PLA endblocks to pull out of micelles as the L/D ratio is increased and PLLA crystallization occurs, and a decrease in the number of bridging chains for micelles with crystalline PLA domains, as formation of bridges may be hindered by crowded crystalline PLA domains. Ultra-small angle neutron scattering (USANS) and confocal microscopy shows evidence of larger structures in these gels, reminiscent of the hierarchical structures observed in biological gels. These results provide a new strategy for controlling the rheology of PLA-based hydrogels for potential applications in biomaterials, as well as fundamental insights into how intermicellar interactions can be tuned via stereochemistry. Collectively, our work shows that stereochemistry can be used in unexpected ways to access novel structures and properties in relatively simple synthetic polymers, giving insight into new routes for creating complex soft materials. Please click Additional Files below to see the full abstract

The X-ray and extreme-ultraviolet flux evolution of SS Cygni throughout outburst

We present the most complete multiwavelength coverage of any dwarf nova outburst: simultaneous optical, Extreme Ultraviolet Explorer, and Rossi X-ray Timing Explorer observations of SS Cygni throughout a narrow asymmetric outburst. Our data show that the high-energy outburst begins in the X-ray waveband 0.9--1.4d after the beginning of the optical rise and 0.6d before the extreme-ultraviolet rise. The X-ray flux drops suddenly, immediately before the extreme-ultraviolet flux rise, supporting the view that both components arise in the boundary layer between the accretion disc and white dwarf surface. The early rise of the X-ray flux shows the propagation time of the outburst heating wave may have been previously overestimated. The transitions between X-ray and extreme-ultraviolet dominated emission are accompanied by intense variability in the X-ray flux, with timescales of minutes. As detailed by Mauche & Robinson, dwarf nova oscillations are detected throughout the extreme-ultraviolet outburst, but we find they are absent from the X-ray lightcurve. X-ray and extreme-ultraviolet luminosities imply accretion rates of 3e15g/s in quiescence, 1e16g/s when the boundary layer becomes optically thick, and \~1e18g/s at the peak of the outburst. The quiescent accretion rate is two and a half orders of magnitude higher than predicted by the standard disc instability model, and we suggest this may be because the inner accretion disc in SS Cyg is in a permanent outburst state.Comment: 15 pages, 14 figures; accepted for publication in MNRA

Multimodal Imaging of Macular Telangiectasia Type 2: Focus on Vascular Changes Using Optical Coherence Tomography Angiography

PURPOSE. To report morphologic features of idiopathic macular telangiectasia (MacTel) type 2 by means of optical coherence tomography angiography (OCTA) and to compare these findings to fundus fluorescein angiography (FFA), fundus autofluorescence (FAF), confocal blue reflectance (CBR), and spectral-domain OCT (SD-OCT). In addition, foveal vessel density and parafoveal vascular density (PFVD), and foveal retinal thickness and parafoveal retinal thickness (PFRT) were compared between MacTel 2 patients and normal aged-matched controls. METHODS. Eight patients (15 eyes) with MacTel 2 and 17 normal controls (17 eyes) underwent retinal multimodal imaging assessment and grading. Results from different imaging techniques were used to compare interimaging modalities. Objective quantification of retinal vessel density and macular thickness was evaluated in MacTel 2 patients (15 eyes). RESULTS. In MacTel 2 eyes a comparison of OCTA to the other imaging techniques showed that the strongest correlations were present with SD-OCT, early FFA, and late FFA. Moderate correlations were found between OCTA and CBR and FAF. Foveal vessel density was significantly lower in MacTel 2 eyes than control eyes both in the superficial plexus (23.74% vs. 33.14%; P = 0.003) and in the deep plexus (24.63% vs. 34.21%; P = 0.005). Superficial PFVD was significantly different in the two groups (47.06% vs. 51.40%; P = 0.005) but not the deep PFVD. Foveal retinal thickness was 214.13 mu m in MacTel 2 eyes and 258.18 mu m in normal controls, and PFRT was 279.60 and 323.29 mu m, respectively (P CONCLUSIONS. Optical coherence tomography angiography is useful for retinal vasculature characterization in MacTel type 2 patients and showed a high correlation with well-established imaging techniques

Transcriptome analysis of antigenic variation in Plasmodium falciparum - var silencing is not dependent on antisense RNA

BACKGROUND: Plasmodium falciparum, the causative agent of the most severe form of malaria, undergoes antigenic variation through successive presentation of a family of antigens on the surface of parasitized erythrocytes. These antigens, known as Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) proteins, are subject to a mutually exclusive expression system, and are encoded by the multigene var family. The mechanism whereby inactive var genes are silenced is poorly understood. To investigate transcriptional features of this mechanism, we conducted a microarray analysis of parasites that were selected to express different var genes by adhesion to chondroitin sulfate A (CSA) or CD36. RESULTS: In addition to oligonucleotides for all predicted protein-coding genes, oligonucleotide probes specific to each known var gene of the FCR3 background were designed and added to the microarray, as well as tiled sense and antisense probes for a subset of var genes. In parasites selected for adhesion to CSA, one full-length var gene (var2csa) was strongly upregulated, as were sense RNA molecules emanating from the 3' end of a limited subset of other var genes. No global relationship between sense and antisense production of var genes was observed, but notably, some var genes had coincident high levels of both antisense and sense transcript. CONCLUSION: Mutually exclusive expression of PfEMP1 proteins results from transcriptional silencing of non-expressed var genes. The distribution of steady-state sense and antisense RNA at var loci are not consistent with a silencing mechanism based on antisense silencing of inactive var genes. Silencing of var loci is also associated with altered regulation of genes distal to var loci

The Evolution of Late-Time Optical Emission From SN 1979C

Optical spectra of the bright Type II-L supernova SN 1979C obtained in April 2008 with the 6.5 m MMT telescope are compared with archival late-time spectra to follow the evolution of its optical emission over the age range of 11 to 29 years. We estimate an Halpha flux decrease of around 35% from 1993 to 2008 but noticeable increases in the strength of blueshifted emission of forbidden oxygen lines. While the maximum expansion of the broad ~6700 km/s Halpha emission appears largely unchanged from 1993, we find a significant narrowing of the double-peaked emission profiles in the [O I] 6300, 6364 and [O II] 7319, 7330 lines. A comparison of late-time optical spectra of a few other Type II supernovae which, like SN 1979C, exhibit bright late-time X-ray, optical, and radio emissions, suggests that blueshifted double-peaked oxygen emission profiles may be a common phenomenon. Finally, detection of a faint, broad emission bump centered around 5800 Angstroms suggests the presence of WC type Wolf-Rayet stars in the supernova's host star cluster.Comment: 6 pages, 4 figures, 1 table. Matches version accepted by Ap

Evaluation of a prostate cancer e-health-tutorial

Hintergrund: Angesichts verschiedener Behandlungsoptionen ist die Information und Therapieentscheidung beim lokalisierten Prostatakarzinom eine Herausforderung. Die digitale Informationstechnologie bietet im Vergleich zu gedruckten Informationen mehr Möglichkeiten, die Information und die Patientenkommunikation bedarfsgerecht zu gestalten. Ziele: Zur Unterstützung der Therapieentscheidung und der Kommunikation mit Patienten ist in der deutschsprachigen Schweiz ein Online-Tutorial in einem systematischen Prozess entwickelt und in einer Pilotstudie getestet worden. In der Evaluation interessierten die Nutzerzufriedenheit, die Erfüllung der Informationsbedürfnisse, die Vorbereitung auf die Therapieentscheidung und deren subjektive Qualität. Material und Methoden: Die Plattform wurde in einem iterativen Prozess mittels Fokusgruppen mit Ärzten und Patienten auf der Grundlage von Informationen aus bestehenden Broschüren entwickelt. Für den Test der Plattform wurden in 8 urologischen Kliniken 87 Patienten zur Teilnahme eingeladen. Die 56 Nutzer wurden 4 Wochen nach dem Login und 3 Monate nach dem Therapieentscheid online befragt, 48 Nutzer füllten beide Befragungen aus. Eingesetzte Instrumente waren die Preparation for Decision Making Scale (PDMS), die Decisional Conflict Scale (DCS) und die Decisional Regret Scale (DRS). Ergebnisse und Diskussion: Die Nutzenden sind mit der Plattform sehr zufrieden und finden ihre Informationsbedürfnisse gut erfüllt. Sie zeigen 3 Monate nach dem Entscheid eine gute Vorbereitung auf die Entscheidung (MW PDMS 75, SD 23) und berichten über niedrigen Entscheidungskonflikt (MW DCS 9.6, SD 11) und kaum Bedauern über die Entscheidung (MW DRS 6.4, SD 9.6). Basierend auf diesen Erkenntnissen kann die Plattform zur weiteren Nutzung empfohlen werden.Background: Due to the multitude of therapy options the treatment decision after diagnosis of a localised prostate cancer is challenging. Compared to printed booklets, web based information technology offers more possibilities to tailor information to patients’ individual needs. Objectives: To support the decision making process as well as the communication with patients we developed an online tutorial in a systematic process in the German speaking part of Switzerland and then tested it in a pilot study. The study investigated users’ satisfaction, the coverage of information needs, the preparation for decision making and the subjective quality of the decision. Materials and methods: Based on already existing information material the online tutorial was developed in an iterative process using focus groups with patients and urologists. For the following evaluation in eight clinics a total of 87 patients were invited to access the platform and participate in the study. From these patients 56 used the tutorial and 48 answered both surveys (the first one 4 weeks after the first login and the second one 3 months after treatment decision). The surveys used the Preparation for Decision Making Scale (PDMS), the Decisional Conflict Scale (DCS), and the Decisional Regret Scale (DRS). Results and Conclusion: Satisfaction with the tutorial is very high among patients with newly diagnosed localized prostate cancer. Users find their information needs sufficiently covered. Three months after the decision they felt that they were well prepared for the decision making (Mean PDMS 75, SD 23), they had low decisional conflict (Mean DCS 9.6, SD 11) and almost no decisional regret (Mean DRS 6.4, SD 9.6). Based on these findings the further use of the tutorial can be recommended

Brevenal Inhibits Pacific Ciguatoxin-1B-Induced Neurosecretion from Bovine Chromaffin Cells

Ciguatoxins and brevetoxins are neurotoxic cyclic polyether compounds produced by dinoflagellates, which are responsible for ciguatera and neurotoxic shellfish poisoning (NSP) respectively. Recently, brevenal, a natural compound was found to specifically inhibit brevetoxin action and to have a beneficial effect in NSP. Considering that brevetoxin and ciguatoxin specifically activate voltage-sensitive Na+ channels through the same binding site, brevenal has therefore a good potential for the treatment of ciguatera. Pacific ciguatoxin-1B (P-CTX-1B) activates voltage-sensitive Na+ channels and promotes an increase in neurotransmitter release believed to underpin the symptoms associated with ciguatera. However, the mechanism through which slow Na+ influx promotes neurosecretion is not fully understood. In the present study, we used chromaffin cells as a model to reconstitute the sequence of events culminating in ciguatoxin-evoked neurosecretion. We show that P-CTX-1B induces a tetrodotoxin-sensitive rise in intracellular Na+, closely followed by an increase in cytosolic Ca2+ responsible for promoting SNARE-dependent catecholamine secretion. Our results reveal that brevenal and β-naphtoyl-brevetoxin prevent P-CTX-1B secretagogue activity without affecting nicotine or barium-induced catecholamine secretion. Brevenal is therefore a potent inhibitor of ciguatoxin-induced neurotoxic effect and a potential treatment for ciguatera