Het effect van preventie van infectieziekten bij reizigers naar de (sub)tropen

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The consequences of malaria infection in pregnant women and their infants

Preliminary results are presented from this study which indicate that 84.8 of pregnant women present at first antenatal visit with anemia (Hb 11g/dl) an 8.7 of their infants (n = 230) have a hemoglobin at birth below 14g/dl. There is an association between pregnancy anemia and malaria. A case control study in pregnant women and an infant cohort study to 18 months of age, are employed to study the cause and effects of anemia and malaria on women and their infants health

A member of the TERMINAL FLOWER1/CENTRORADIALIS gene family controls sprout growth in potato tubers

Potato tuber bud dormancy break followed by premature sprouting is a major commercial problem which results in quality losses and decreased tuber marketability. An approach to controlling premature tuber sprouting is to develop potato cultivars with a longer dormancy period and/or reduced rate of sprout growth. Our recent studies using a potato diploid population have identified several quantitative trait loci (QTLs) that are associated with tuber sprout growth. In the current study, we aim to characterize a candidate gene associated with one of the largest effect QTLs for rapid tuber sprout growth on potato chromosome 3. Underlying this QTL is a gene encoding a TERMINAL FLOWER 1/CENTRORADIALIS homologue (PGSC0003DMG400014322). Here, we use a transgenic approach to manipulate the expression level of the CEN family member in a potato tetraploid genotype (cv. Désirée). We demonstrate a clear effect of manipulation of StCEN expression, with decreased expression levels associated with an increased rate of sprout growth, and overexpressing lines showing a lower rate of sprout growth than controls. Associated with different levels of StCEN expression were different levels of abscisic acid and cytokinins, implying a role in controlling the levels of plant growth regulators in the apical meristem

Inhibition of Akt sensitises neuroblastoma cells to gold(III) porphyrin 1a, a novel antitumour drug induced apoptosis and growth inhibition

Background:Gold(III) porphyrin 1a is a new class of anticancer drug, which inhibits cell proliferation of wide range of human cancer cell lines and induces apoptosis in human nasopharyngeal carcinoma cells. However, the underlying signalling mechanism by which gold(III) porphyrin 1a modifies the intracellular apoptosis pathways in tumour cells has not been explained in detail in neuroblastoma cells.Methods:Cell proliferation and apoptosis were determined by measuring 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Annexin V binding, respectively. Western blot assay was used to detect proteins involved in apoptotic and Akt pathways. In vivo tumour growth was assessed by inoculating tumour cells to nude mice subcutaneously, and gold(III) porphyrin 1a was administrated intravenously.Results:This study assessed the antitumour effect and mechanism of gold(III) porphyrin 1a on neuroblastoma in vitro and in vivo. Gold(III) porphyrin 1a displayed a growth inhibition and induction of apoptosis in neuroblastoma cells effectively in vitro, which was accompanied with release of cytochrome c and Smac/DIABLO and caspases activation. Further studies indicated that gold(III) porphyrin 1a inhibited X-linked inhibitor of apoptosis (XIAP). However, we found that gold(III) porphyrin 1a can induce a survival signal, Akt activation within minutes and could last for at least 24 h. To further confirm association between activation of Akt and the effectiveness of gold(III) porphyrin 1a, neuroblastoma cells were treated with API-2, an Akt-specific inhibitor. API-2 sensitised cells to gold(III) porphyrin 1a-induced apoptosis and growth inhibition.Conclusion:These results suggested that Akt may be considered as a molecular brake that neuroblastoma cells rely on to slow down gold(III) porphyrin 1a-induced apoptosis and antiproliferation. Gold(III) porphyrin 1a is a mitochondrial apoptotic stimulus but also activates Akt, suggesting an involvement of Akt in mediating the effectiveness to growth inhibition and apoptosis by gold(III) porphyrin 1a and that inhibition of Akt can enhance the anticancer activity of gold(III) porphyrin 1a in neuroblastoma. © 2009 Cancer Research UK.published_or_final_versio

Stereospecificity of inositol hexakisphosphate dephosphorylation by Paramecium phytase.

InsP6 is an abundant compound in many micro-organisms, plants and animal cells. Its function and route of synthesis are still largely unknown. Degradation of InsP6 is mediated by phytase, which in most organisms dephosphorylates InsP6 in a relatively non-specific way. In the micro-organism Paramecium, however, the enzyme has been shown to dephosphorylate InsP6 to InsP2 in a specific order, but its stereospecificity has not been established, i.e. the phosphates are removed in the sequence 6/5/4/3 or 6/5/4/1 or 4/5/6/1 or 4/5/6/3 [Freund, Mayr, Tietz and Schultz (1992) Eur. J. Biochem. 207, 359-367]. We have isolated the InsP4 intermediate and identified its absolute configuration as D-Ins(1,2,3,4)P4. Furthermore, degradation of [3,5-32P]InsP6 yielded a 32P-labelled InsP2 isomer, D-Ins(2,3)P2. These data demonstrate that Paramecium phytase removes the phosphates of InsP6 in the sequence 6/5/4/1. Knowing the stereochemical course of the enzyme, it can be used to elucidate the route of InsP6 synthesis, as it allows us to determine the specific radioactivity at individual positions of the molecular after pulse-labelling cells with [32P]P1 in vivo or [gamma-32P]ATP in vitro