75 research outputs found

    Multiple var2csa-Type PfEMP1 Genes Located at Different Chromosomal Loci Occur in Many Plasmodium falciparum Isolates

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    BACKGROUND:The var2csa gene encodes a Plasmodium falciparum adhesion receptor which binds chondroitin sulfate A (CSA). This var gene is more conserved than other PfEMP1/var genes and is found in all P. falciparum isolates. In isolates 3D7, FCR3/It4 and HB3, var2csa is transcribed from a sub-telomeric position on the left arm of chromosome 12, but it is not known if this location is conserved in all parasites. Genome sequencing indicates that the var2csa gene is duplicated in HB3, but whether this is true in natural populations is uncertain. METHODOLOGY/PRINCIPAL FINDINGS:To assess global variation in the VAR2CSA protein, sequence variation in the DBL2X region of var2csa genes in 54 P.falciparum samples was analyzed. Chromosome mapping of var2csa loci was carried out and a quantitative PCR assay was developed to estimate the number of var2csa genes in P.falciparum isolates from the placenta of pregnant women and from the peripheral circulation of other malaria patients. Sequence analysis, gene mapping and copy number quantitation in P.falciparum isolates indicate that there are at least two loci and that both var2csa-like genes can be transcribed. All VAR2CSA DBL2X domains fall into one of two distinct phylogenetic groups possessing one or the other variant of a large (approximately 26 amino acid) dimorphic motif, but whether either motif variant is linked to a specific locus is not known. CONCLUSIONS/SIGNIFICANCE:Two or more related but distinct var2csa-type PfEMP1/var genes exist in many P. falciparum isolates. One gene is on chromosome 12 but additional var2csa-type genes are on different chromosomes in different isolates. Multiplicity of var2csa genes appears more common in infected placentae than in samples from non-pregnant donors indicating a possible advantage of this genotype in pregnancy associated malaria

    Impact of educational interventions on adolescent attitudes and knowledge regarding vaccination: A pilot study

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    © 2018 Carolan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background Current immunisation levels in England currently fall slightly below the threshold recommended by the World Health Organization, and the three-year trend for vaccination uptake is downwards. Attitudes towards vaccination can affect future decisions on whether or not to vaccinate, and this can have significant public health implications. Interventions can impact future vaccination decisions, and these interventions can take several forms. Relatively little work has been reported on the use of vaccination interventions in young people, who form the next generation of individuals likely to make vaccination decisions. Method We investigated the impact of two different types of educational intervention on attitudes towards vaccination in young people in England. A cohort of young people (n = 63) was recruited via a local school. This group was divided into three sub-groups; one (n = 21) received a presentation-based intervent ion, one (n = 26) received an interactive simulation-based intervention, and the third (n = 16) received no intervention. Participants supplied information on (1) their attitudes towards vaccination, and (2) their information needs and views on personal choice concerning vaccination, at three time points: immediately before and after the intervention, and after six months. Results Neither intervention had a significant effect on participants’ attitudes towards vaccination. However, the group receiving the presentation-based intervention saw a sustained uplift in confidence about information needs, which was not observed in the simulation-based intervention group. Discussion Our findings with young people are consistent with previous work on vaccination interventions aimed at adults, which have shown limited effectiveness, and which can actually reduce intention to vaccinate. Our findings on the most effective mode of delivery for the intervention should inform future discussion in the growing “games for health” domain, which proposes the use of interactive digital resources in healthcare education

    Chickpea

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    The narrow genetic base of cultivated chickpea warrants systematic collection, documentation and evaluation of chickpea germplasm and particularly wild Cicer species for effective and efficient use in chickpea breeding programmes. Limiting factors to crop production, possible solutions and ways to overcome them, importance of wild relatives and barriers to alien gene introgression and strategies to overcome them and traits for base broadening have been discussed. It has been clearly demonstrated that resistance to major biotic and abiotic stresses can be successfully introgressed from the primary gene pool comprising progenitor species. However, many desirable traits including high degree of resistance to multiple stresses that are present in the species belonging to secondary and tertiary gene pools can also be introgressed by using special techniques to overcome pre- and post-fertilization barriers. Besides resistance to various biotic and abiotic stresses, the yield QTLs have also been introgressed from wild Cicer species to cultivated varieties. Status and importance of molecular markers, genome mapping and genomic tools for chickpea improvement are elaborated. Because of major genes for various biotic and abiotic stresses, the transfer of agronomically important traits into elite cultivars has been made easy and practical through marker-assisted selection and marker-assisted backcross. The usefulness of molecular markers such as SSR and SNP for the construction of high-density genetic maps of chickpea and for the identification of genes/QTLs for stress resistance, quality and yield contributing traits has also been discussed

    Variations in killer-cell immunoglobulin-like receptor and human leukocyte antigen genes and immunity to malaria

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    Malaria is one of the deadliest infectious diseases in the world. Immune responses to Plasmodium falciparum malaria vary among individuals and between populations. Human genetic variation in immune system genes is likely to play a role in this heterogeneity. Natural killer (NK) cells produce inflammatory cytokines in response to malaria infection, kill intraerythrocytic Plasmodium falciparum parasites by cytolysis, and participate in the initiation and development of adaptive immune responses to plasmodial infection. These functions are modulated by interactions between killer-cell immunoglobulin-like receptors (KIR) and human leukocyte antigens (HLA). Therefore, variations in KIR and HLA genes can have a direct impact on NK cell functions. Understanding the role of KIR and HLA in immunity to malaria can help to better characterize antimalarial immune responses. In this review, we summarize the different KIR and HLA so far associated with immunity to malaria.This work was supported through the DELTAS Africa Initiative (Grant no. 107743), that funded Stephen Tukwasibwe through PhD fellowship award, and Annettee Nakimuli through group leader award. The DELTAS Africa Initiative is an independent funding scheme of the African Academy of Science (AAS), Alliance for Accelerating Excellence in Science in Africa (AESA) and supported by the New Partnership for Africa’s Development Planning and Coordinating Agency (NEPAD Agency) with funding from the Wellcome Trust (Grant no. 107743) and the UK government. Francesco Colucci is funded by Wellcome Trust grant 200841/Z/16/Z. The project received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 695551) for James Traherne and John Trowsdale. Jyothi Jayaraman is a recipient of fellowship from the Centre for Trophoblast Research

    North American Wild Relatives of Grain Crops

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    The wild-growing relatives of the grain crops are useful for long-term worldwide crop improvement research. There are neglected examples that should be accessioned as living seeds in gene banks. Some of the grain crops, amaranth, barnyard millet, proso millet, quinoa, and foxtail millet, have understudied unique and potentially useful crop wild relatives in North America. Other grain crops, barley, buckwheat, and oats, have fewer relatives in North America that are mostly weeds from other continents with more diverse crop wild relatives. The expanding abilities of genomic science are a reason to accession the wild species since there are improved ways to study evolution within genera and make use of wide gene pools. Rare wild species, especially quinoa relatives in North American, should be acquired by gene banks in cooperation with biologists that already study and conserve at-risk plant populations. Many of the grain crop wild relatives are weeds that have evolved herbicide resistance that could be used in breeding new herbicide-resistant cultivars, so well-documented examples should be accessioned and also vouchered in gene banks
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