124 research outputs found
Growth temperature regulation of host-specific modifications of rhizobial lipo-chitin oligosaccharides::: the function of nodX is temperature regulated
Lipo-chitin oligosaecharides (LCOs) are usually produced and isolated for structural analysis from bacteria cultured under laboratory rather than field conditions. We have studied the influence of bacterial growth temperature on the LCO structures produced by different Rhizobium leguminosarum strains, using thin-layer chromatographic, high-performance liquid chromatographic, and mass spectrometric analyses. Wild-type R, leguminosarum by. viciae Al was shown to produce larger relative amounts of nodX-mediated, acetylated LCOs at 12 degrees C than at 28 degrees C, indicating that the activity of nodX (a gene encoding an LCO O-acetyl transferase) is temperature dependent. Interestingly, symbiotic resistance genes sym1 and sym2 found in primitive pea cultivars are also temperature sensitive, only being active at low temperatures, at which they block nodulation by R. leguminosarum by. viciae strains lacking nodX: We therefore propose that the gene-for-gene relationship between plant and bacterium has a temperature-sensitive mechanism as an adaptation to environmental conditions. An R, leguminosarum by. trifolii strain was also shown to produce larger relative amounts of nodX-mediated, acetylated LCOs at 12 degrees C than at 28 degrees C. The major components synthesized by the two strains are produced at both temperatures but in different relative amounts, while some minor components are only produced at one of the two temperatures.Microbial Biotechnolog
Stable isotope dilution assay for the accurate determination of mycotoxins in maize by UHPLC-MS/MS
A fast, easy-to-handle and cost-effective analytical method for 11 mycotoxins currently regulated in maize and other cereal-based food products in Europe was developed and validated for maize. The method is based on two extraction steps using different acidified acetonitrile–water mixtures. Separation is achieved using ultrahigh-performance liquid chromatography (UHPLC) by a linear water–methanol gradient. After electrospray ionisation, tandem mass spectrometric detection is performed in dynamic multiple reaction monitoring mode. Since accurate mass spectrometric quantification is hampered by matrix effects, uniformly [13C]-labelled mycotoxins for each of the 11 compounds were added to the sample extracts prior to UHPLC-MS/MS analysis. Method performance parameters were obtained by spiking blank maize samples with mycotoxins before as well as after extraction on six levels in triplicates. The twofold extraction led to total recoveries of the extraction steps between 97% and 111% for all target analytes, including fumonisins. The [13C]-labelled internal standards efficiently compensated all matrix effects in electrospray ionisation, leading to apparent recoveries between 88% and 105% with reasonable additional costs. The relative standard deviations of the whole method were between 4% and 11% for all analytes. The trueness of the method was verified by the measurement of several maize test materials with well-characterized concentrations. In conclusion, the developed method is capable of determining all regulated mycotoxins in maize and presuming similar matrix effects and extraction recovery also in other cereal-based foods
Spisulosine (ES-285) given as a weekly three-hour intravenous infusion: results of a phase I dose-escalating study in patients with advanced solid malignancies
Spisulosine is a marine compound that showed antitumor activity in preclinical studies. We report results of a phase I trial performed in patients with advanced solid tumors with the marine compound, with the aim to determine the maximum tolerated dose (MTD) of a weekly 3-h intravenous (iv.) infusion, and to evaluate the safety, efficacy, and pharmacokinetics (PK) of the compound. Two centers contributed 25 patients to the trial, and 7 dose levels were explored. In dose levels ranging from 4 to 128 mg/mA(2)/day, no dose-limiting toxicities (DLT) were observed. One patient had DLT at 200 mg/mA(2), a reversible grade 3 ALT increase. The MTD was not reached due to early termination of the Spisulosine trial program but is considered to be likely in the range of 200 mg/mA(2) for this schedule. Drug-related adverse reactions included mild to moderate nausea, pyrexia, injection site reactions, and vomiting. One case of grade 4 peripheral motor and sensory neuropathy associated with general weakness and pain was observed during treatment cycle 4 and possibly contributed to the death of the patient. Grade 3 laboratory abnormalities included anemia and lymphopenia and increases in liver enzymes (alkaline phosphatase, transaminases, and bilirubin). Objective responses were not observed, and only four patients had short-lasting stable disease (< 3 months). The PK data indicated a wide distribution, a long residence time, and dose proportionality of the agent. Hepato- and neuro-toxicity are schedule independent dose-limiting adverse events for this marine compound, as illustrated by this and other early clinical trials
How to Influence National Pride? The Olympic Medal Index as a Unifying Narrative
Elite sport is often regarded as one of the main vehicles for articulating national pride and stimulating national cohesion. In this article, we explore a variety of different notions of pride and nationality as related to success in elite sport. We present the results of a public survey, which measured some of the effects on national pride in the Netherlands, related to the men's European Football Championships, the Tour de France, Wimbledon and the Olympic Games in Beijing (all in the summer of 2008). The results suggest that a sense of belonging is a necessary condition that precedes rather than results from sport-related pride. This supports the notion of national pride being a rather stable characteristic of countries, notwithstanding specific situations (such as sport success) that may lead to minor and temporary fluctuations. There seems to be no empirical evidence for the - primarily quantitatively understood - concept of pride (as a 'bucket-notion'), which is often implicit to the political rhetoric used to increase sport funding with the aim of winning more medals to generate an increase in national pride. © The Author(s) 2010
Traumatic neuroma of the superficial peroneal nerve in a patient: a case report and review of the literature
Van wingewest naar zelfbestuur in Nederl. Indië /
Herkomst: Bibliotheek Ger Schmook jr.Letterenhuis Antwerpen via Universiteitsarchief Gen
Measuring the restoration trajectory of invertebrates in the Winstone Aggregates Hunua quarry site
In this study we surveyed Winstone Aggregates Hunua Quarry restoration plantings for invertebrates. We wanted to measure the restoration success and used an unplanted control site and a mature forest site in the same area as a comparison. Using different entomological surveying techniques we found that ground beetle and centipede numbers
increased from the control site through to the mature forest. Tree weta was well represented in the restored area, while ants, earthworms and rove beetles resulted in a downwards trend from the mature area to the control site. Five native species of snail were found only in the mature forest. Previous studies such as Bowie et al. (2012) Punakaiki
restoration project, found similar trends. Both this study and the Punakaiki project are baseline studies. Further research is proposed for the future
Identification of potential invertebrate bioindicators of restoration trajectory at a quarry site in Hunua, Auckland, New Zealand
In 2009, the New Zealand company Winstone Aggregates initiated a restoration planting scheme to mitigate the ecological damage caused by mining at the Hunua Quarry, near Papakura, New Zealand. By employing several collection methods (pitfall traps, artificial cover objects, litter samples, weta motels), and comparing invertebrates found in the restoration area with those found in adjacent areas of mature forest and unplanted grassland, this study aimed to identify invertebrates that could be used as bioindicators of restoration trajectory. Multivariate analyses (NMDS, ANOSIM) indicated that the composition of some invertebrate assemblages (e.g. beetles, mites, springtails) may be used to determine whether assemblages in the restoration areas had converged towards those in the mature forest. The survey also identified specific taxa (e.g. cave weta, spiders) that were more abundant in, or exclusive to, the mature forest, and identified other groups (e.g. exotic earthworms, slugs, snails) that typified the grassland invertebrates. Thus, in future invertebrate assessments, an abundance of the former taxa, and lack of the latter, would provide an indication of restoration ‘success’, and assist in monitoring the trajectory of the invertebrate community from that found in the exotic grassland towards an assemblage more typical of the native forest habitat of this region
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