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The anaerobic cleavage of ether bonds of methoxylated substrates such as vanillate or veratrol in acetogenic bacteria is mediated by multi-component enzyme systems, the O-demethylases. Acetobacterium dehalogenans harbours different inducible O-demethylases with various substrate spectra. Two of these enzyme systems, the vanillate- and the veratrol-O-demethylases, have been characterized so far. One component of this enzyme system, the methyltransferase I (MT I), catalyses the cleavage of the substrate ether bond and the subsequent transfer of the methyl group to a corrinoid protein. For the C-termini of the methyltransferases I of the vanillate- and the veratrol-O-demethylases, a TIM barrel structure of the enzymes was predicted, whereas the N-termini are not part of this conserved structure. The deletion of the N-terminal regions led to a significant increase of activity (up to 20-fold) and an extended substrate spectrum of the mutants, which also comprised non-aromatic compounds such as the thioether methionine and diethylether. The exchange of the N-termini of the two methyltransferases I resulted in chimeric enzymes whose substrate specificities were those of the enzymes from which the N-termini were derived. This demonstrated the crucial role of the N-termini for the substrate specificity of the methyltransferases., (© 2010 Blackwell Publishing Ltd.)

Confusion still exists in the diagnosis of drug-induced immune haemolysis (DIH). The aim of this study was to demonstrate antibodies specific to 5-fluorouracil (5-FU) in a patient with fatal immune haemolysis (IH). The case of a patient who died due to protracted IH is described. A 57-year-old female underwent treatment with oxaliplatin, 5-FU and folinic acid due to cholangiocarcinoma. Following drug administration, she was transfused because of a mild non-haemolytic anaemia and died following haemolysis. Serological testing including antibody screening, direct antiglobulin test and detection of drug-dependent antibodies was performed using standard techniques. The patient's serum was observed to be red in colour due to the presence of free haemoglobin prior to and following blood transfusion, and contained antibodies reactive with RBCs only in the presence of urine from several patients treated with 5-FU (ex vivo antigens). Drug-induced immune haemolysis (DIH) and metabolite-dependent antibodies should always be taken into consideration when a patient being administered any type of drug develops haemolysis.

Once thought to be dominated by a few genets, clonal plant populations can contain high levels of genetic diversity. Sexual reproduction and vegetative growth strategy affect the amount and distribution of genetic diversity within clonal plant populations. We determined the scale of genetic diversity in a population of Vaccinium stamineum, a clonal shrub that forms discrete patches. Using the random amplified polymorphic DNA (RAPD) technique, we surveyed the genetic diversity of V. stamineum within and among patches from a 1-ha site. We found 67 unique RAPD profiles among the 99 sampled individuals from 22 patches. In two patches, all the sampled individuals had the same RAPD profile. In seven patches, every individual sampled had a different RAPD profile. The remaining patches showed mixed RAPD profiles which suggested both clonal and sexual reproduction. Each unique RAPD profile was restricted to one patch (with one exception), which suggests that clonal growth occurs at the patch scale. High levels of genetic variation within some patches may be explained by somatic mutation; however, seedling recruitment is a more likely explanation.