Partial purification and characterization of a jasmonic acid conjugate cleaving amidohydrolase from the fungus Botryodiplodia theobromae

AbstractA protein preparation from the mycelium of the tropical pathogenic fungus Botryodiplodia theobromae revealed a novel peptidase activity. This enzyme was capable of cleaving conjugates of jasmonic acid with α-amino acids. The protein was enriched 108-fold by gel filtration, ion exchange and hydrophobic interaction chromatography. The enzyme was found to be a glycoprotein with a molecular mass of about 107 kDa. The amidohydrolase seems to be very specific with regard to (−)-jasmonic acid and α-amino acids with (S)-configuration

A dimolybdenum paddlewheel as a building block for heteromultimetallic structures

Diphenylphosphine functionalized propionic acid was applied for the synthesis of heteromultimetallic dimolybdenum(II) complexes. The ligand features both carboxylic acid and phosphine functionalities, allowing the selective synthesis of a tetracarboxylate bridged Mo2(II)-paddlewheel structure in a first step. Due to the symmetrically arranged phosphine functionalities, the dimolybdenum(II) complex was utilized as a metalloligand. Subsequent coordination of late transition metal ions, such as gold(I), rhodium(I), iridium(I) or ruthenium(II) to the phosphine moieties allowed the formation of heteromultimetallic structures. The flexibility of the diphenylphosphino propionate ligand system enabled intermolecular aurophilic interactions in the Au(I) functionalized dimolybdenum(II) complexes. Depending on the Au(I) species applied, either a dimeric structure or a 1D coordination polymer was formed in the solid state. These structures represent the first examples of heterometallic dimolybdenum(II) complexes, forming supramolecular structures via aurophilic interactions

Ecto-5’-nucleotidase: Structure function relationships

Ecto-5’-nucleotidase (ecto-5’-NT) is attached via a GPI anchor to the extracellular membrane, where it hydrolyses AMP to adenosine and phosphate. Related 5’-nucleotidases exist in bacteria, where they are exported into the periplasmic space. X-ray structures of the 5’-nucleotidase from E. coli showed that the enzyme consists of two domains. The N-terminal domain coordinates two catalytic divalent metal ions, whereas the C-terminal domain provides the substrate specificity pocket for the nucleotides. Thus, the substrate binds at the interface of the two domains. Here, the currently available structural information on ecto-5’NT is reviewed in relation to the catalytic properties and enzyme function

CryoSat Cal/Val – Accuracy and Penetration Depth of the CryoSat SARIn product

CryoSat-2 was launched in April 2010, as part of the European Space agency's (ESA) Earth Opportunity Programmes. The primary scientific objectives of the mission are to determine changes of the ice sheet elevation and sea ice thickness within its nominal lifetime of five years to get a better understanding of the short-term response of the Cryosphere to climate change. In order to validate the scientific data products four post-launch CryoSat Calibration/Validation Experiments (CryoVEx) were carried out since CryoSat-2’s successful launch. The CryoVEx campaigns included co-coordinated field and airborne measurements at selected validation sites in the Arctic and Antarctica. We will present first results of CryoSat-2 comparisons with GPS data acquired at the Halvfarryggen ice dome in Dronning-Maud-Land (DML), Antarctica during CryoVExANT-2010. A second comparison will be shown with airborne laser scanner data acquired during the same campaign in the Blue Ice area next to Novo runway also situated in DML. The GPS and laser scanner data will be used as reference elevation for the analysis. For our comparisons, we use CryoSat-2 level 1b and level 2 data products acquired in the SARIn mode, since the validation sites are close to the coast with surface slopes of up to one degree. Both sites have different snow/firn properties, which can be used to determine the penetration depth of the Ku-Band signal. The area around Halvfarryggen is characterised by a strong east-west gradient in snow accumulation rate, ranging from 0.5 m to 3 m firn per year. The Novo area is pure Blue Ice, covered with small patches of snow. Therefore, different backscatter mechanism will dominate the received radar signal, volume scattering at the Halvfarryggen and surface scattering in the Blue Ice area, respectively. For volume scattering, the re-tracked surface elevation is typically biased with the effective penetration depth of the radar signal. In the Blue Ice area no signal penetration is expected and the re-tracked radar elevation should resemble the GPS determined surface elevation. Apart from results with respect to penetration depth, we will get a first estimate of the accuracy of the CryoSat-2 SARIn product using interferometric phase processing which accounts for across track slopes

Pd-complex driven formation of single-chain nanoparticles

We report the facile synthesis of well-defined palladium(ii) cross-linked single-chain nanoparticles (Pd-SCNPs) using the 'repeating unit approach'. The linear precursor polymer (M<inf>n</inf> ≈ 10200 g mol-1, ≈ 1.17) was synthesized via nitroxide mediated statistical copolymerization of styrene and 4-(chloromethyl)styrene (CMS) followed by a post-polymerization modification of the resulting copolymer to covalently attach the triarylphosphine ligand moieties. The ligand content along the lateral polymer chain was 12%. Intramolecular crosslinking was performed in diluted solution with a suitable precursor complex (Pd[1,5-cyclooctadiene]Cl<inf>2</inf>) to afford the well-defined Pd-SCNPs, which feature a hydrodynamic diameter of D<inf>h</inf> = 5.4 nm. The palladium(ii) containing single-chain nanoparticles were characterized in-depth using 1H NMR spectroscopy, 31P{1H} NMR spectroscopy, dynamic light scattering (DLS), size exclusion chromatography (SEC), 1H spin-spin relaxation time (T<inf>2</inf>) analysis, X-ray photoelectron spectroscopy (XPS), and log-normal distribution (LND) simulations. Finally, the applicability of the Pd-SCNPs as catalyst in the Sonogashira coupling was exemplified. © The Royal Society of Chemistry 2015

Validation of CryoSat-2 products over the East Antarctica Ice Sheet

A main goal of the CryoSat-2 mission is to observe the variations in the elevation of the polar ice sheets within a few centimeters accuracy. To fulfill this challenging objective the CryoSat-2 Level 2 products need to be validated against independent measurements. Kinematic GNSS is a well established method to derive ground based surface elevation profiles with high accuracy, thus providing independent data to investigate the reliability of the radar altimetry observations. During the last decade a variety of such measurements could be realized in cooperation with the Russian Antarctic Expedition (RAE). Since 2007 we have realized the installation of several geodetic GNSS equipments on vehicles of the scientific and logistic convoys. These profiles between the Russian Antarctic research station Vostok (78° 28' S, 106° 50' E) and the coastal stations Mirny and Progress have a length of about 1,600 km each. Over several years the repetition of these profiles show that the elevation change is negligibly small in this region which forms an important precondition when comparing older GNSS profiles with recent CryoSat-2 data. Thus, the GNSS profiles give us the unique opportunity to validate both CryoSat-2 LRM-Mode data in the flat interior of the Antarctic Ice Sheet and SARIn-Mode data in the steep and rough coastal area. Validation results of the crossover analysis with Baseline B data are presented. We show how the new Baseline C processor version improves the observation quality. Furthermore, the alternate AWI processing version is used for comparison. Additionally, we will test the performance of the advanced swath processing technique in areas covered by the SARIn mode. Besides the Level 2 products we furthermore present the results of the validation of different digital elevation models (DEM). The probably most popular DEM for Antarctica, Bedmap2, is based mainly on ICESat, ERS-1 and small-scale local datasets. We show that a DEM based on CryoSat-2 data only has the advantage of a much higher consistency and of less interpolation errors due to the dense satellite ground tracks

The antibody 2B4 directed against the Epstein-Barr virus (EBV)-encoded nuclear antigen I (EBNA I) detects MAGE-4: Implications for studies on the EBV association of human cancers.

We have previously developed two monoclonal antibodies against the Epstein-Barr Virus (EBV) nuclear antigen 1 (EBNA1), designated 1H4 and 2B4. Both detect EBNA1 by in situ staining in established EBV-positive tumours, e.g. Hodgkin's lymphoma and nasopharyngeal carcinoma. An association of EBV with other tumours, notably breast carcinomas, has been reported but remains controversial. Using the antibody 2B4, a nuclear protein has been detected in breast carcinomas that were EBV-negative by other methods, suggesting cross-reactivity with a cellular protein. Furthermore, an association of EBV with various other carcinomas has been reported on the basis of 2B4 immunohistochemistry. Here we show that 2B4 also binds to MAGE-4, a cancer testis antigen expressed in a variety of tumour cells, including breast carcinoma, seminoma and EBV-negative cases of Hodgkin's lymphoma. We conclude that the 2B4 antibody is not suitable for the detection of EBV infection but that additional techniques, particularly in situ hybridization for the detection of the EBV-encoded RNAs (EBERs), should be employed to confirm the presence of EBV. Our results add to the evidence indicating that breast cancer is not an EBV-associated disease

ОПРЕДЕЛЕНИЕ ПРОФИЛЕЙ ВЫСОТ ПОВЕРХНОСТИ ЛЕДНИКА ВДОЛЬ ВНУТРИКОНТИНЕНТАЛЬНЫХ ТРАСС В АНТАРКТИДЕ ПОСРЕДСТВОМ КИНЕМАТИЧЕСКИХ GPS НАБЛЮДЕНИЙ

Surface height profiles of the Antarctic ice sheet were derived from kinematic GPS observations on continental traverses with an accuracy of20 cm. The spectral analysis of the height profile allowed distinguishing different zones of distinct relief properties. The obtained surface height profiles were compared to ICESat satellite laser altimetry data and four different DEMs. A good agreement, within a few decimeters, is found between the in-situ observations and the altimetry data. Among the considered DEMs the model published by Bamber et al., 2009 [3] agrees best with the GPS observations. For three separate elevation zones the standard deviations of the differences of this DEM and the GPS results amount to 0.90 (above3300 melevation), 2.27 (2800–3300 m), and13.92 m(below2800 m). For the Rémy [13] and RAMPv2 [11] DEMs we obtained standard deviations of1.98 mand2.58 m(above3300 m), and4.03 mand5.67 m(2800–3300 m), respectively.С помощью кинематических GPS-наблюдений получены профили высот поверхности Антарктического ледникового щита на внутриконтинентальных трассах с точностью 20 см. Спектральный анализ позволяет выделить зоны с различными свойствами рельефа. Полученные профили высот поверхности сравниваются с данными лазерной альтиметрии спутника ICESat и четырьмя цифровыми моделями высот DEM. Установлено, что данные альтиметрии и наблюдения in-situ согласуются в пределах30 см. Соответствие современных цифровых моделей высот данным GPS-наблюдений для верхней части ледникового купола находится в пределах нескольких метров