129,449 research outputs found
African origin of the malaria parasite Plasmodium vivax.
No full textPlasmodium vivax is the leading cause of human malaria in Asia and Latin America but is absent from most of central Africa due to the near fixation of a mutation that inhibits the expression of its receptor, the Duffy antigen, on human erythrocytes. The emergence of this protective allele is not understood because P. vivax is believed to have originated in Asia. Here we show, using a non-invasive approach, that wild chimpanzees and gorillas throughout central Africa are endemically infected with parasites that are closely related to human P. vivax. Sequence analyses reveal that ape parasites lack host specificity and are much more diverse than human parasites, which form a monophyletic lineage within the ape parasite radiation. These findings indicate that human P. vivax is of African origin and likely selected for the Duffy-negative mutation. All extant human P. vivax parasites are derived from a single ancestor that escaped out of Africa
Letter from S. Gavan Duffy to Hagan
No full textTypescript letter signed S. Gabha?n Ui? Dubhthaigh (Gavan Duffy), Minister of Foreign Affairs, Da?il E?ireann, 16 Kildare Street, Dublin, to Hagan. Realising the necessity to have separate representatives to the Vatican and to the King of Italy when the state is recognised, but arguing that during the transitional period one has to suffice - this should not prejudice them in negotiations with the Vatican 'which has every reason to desire to be on good terms'. Inviting advice
Analysis of recombinant Duffy protein-linked N-glycans using lectins and glycosidases
No full textDuffy antigen is a glycosylated blood group protein acting as a malarial and chemokine receptor. Using glycosylation mutants we have previously demonstrated, that all three potential glycosylation sites of the Duffy antigen are occupied by N-linked oligosaccharide chains. In this study, wild-type Duffy glycoprotein and three mutants, each containing a single N-glycan, were used to characterize the oligosaccharide chains by lectin blotting and endoglycosidase digestion. The positive reaction of all the recombinant Duffy forms with Datura stramonium and Sambucus nigra lectins showed that each Duffy N-linked glycan contains Galβ1-4GlcNAc units terminated by (α2-6)-linked sialic acid residues, typical of complex oligosaccharides. The reactivity with Aleuria aurantia and Lens culinaris lectins suggested the presence of (α1-6)-linked fucose at the N-glycan chitobiose core. The failure of the Galanthus nivalis and Canavalia ensiformis lectins to bind to any of the Duffy mutants or to the wild-type antigen indicated that none of the three Duffy N-glycosylation sites carries detectable levels of high-mannose oligosaccharide chains. Digestion of Duffy samples with peptide N-glycosidase F and endoglycosidase H confirmed the presence of N-linked complex oligosaccharides. Our results indicate that Duffy antigen N-glycans are mostly core-fucosylated complex type oligosaccharides rich in N-acetyllactosamine and terminated by (α2-6)-linked sialic acid residues
Association of Duffy status with asexual parasite density (n = 361).
No full textAssociation of Duffy status with asexual parasite density (n = 361).</p
Synalpheus carpenteri Macdonald and Duffy
No full textSynalpheus carpenteri Macdonald and Duffy Color plate 2 C Material examined. Jamaica: 2 non-ovigerous individuals, ovigerous female (VIMS 08JAM1001,02), Pear Tree Bottom Reef, from canals of Agelas cf. clathrodes. 2 non-ovigerous individuals, 2 ovigerous females (VIMS 08JAM 1301 -03), Pear Tree Bottom Reef, from canals of Agelas cf. dispar. Non-ovigerous individual (VIMS 08JAM 1401), Pear Tree Bottom Reef, from canals of A. cf. clathrodes. Non-ovigerous individual, ovigerous female (VIMS 08JAM1501,02), Pear Tree Bottom Reef, from canals of A. cf. dispar. 9 nonovigerous individuals, 8 ovigerous females (VIMS 08JAM1701,02), Pear Tree Bottom Reef, from canals of A. cf. dispar. 68 non-ovigerous individuals, 21 ovigerous females (VIMS 08JAM 2006 -26,28,29), Pear Tree Bottom Reef, from canals of A. cf. dispar. Non-ovigerous individual (VIMS 08JAM 2101), Pear Tree Bottom Reef, from canals of A. cf. clathrodes. Non-ovigerous individual (VIMS 08JAM 2301), Dairy Bull Reef, from canals of A. cf. clathrodes. Non-ovigerous individual (VIMS 08JAM 2401), Dairy Bull Reef, from canals of A. cf. dispar. 10 non-ovigerous individuals, 3 ovigerous females (VIMS 08JAM 2601 -04), Dairy Bull Reef, from canals of A. cf. dispar. 4 non-ovigerous individuals, 2 ovigerous females (VIMS 08JAM3004,07,08), Dairy Bull Reef, from canals of A. cf. dispar. 4 non-ovigerous individuals, 2 ovigerous females (VIMS 08JAM 3501 - 04), fore-reef (near M 1 channel marker), Discovery Bay, from canals of A. cf. dispar. 11 non-ovigerous individuals, 7 ovigerous females (VIMS 08JAM 3801 -04), fore-reef (near M 1 channel marker), Discovery Bay, from canals of A. cf. dispar. 8 non-ovigerous individuals, 7 ovigerous females (VIMS 08JAM 3901 -08), fore-reef (near M 1 channel marker), Discovery Bay, from canals of A. cf. dispar. 2 non-ovigerous individuals (VIMS 08JAM4106,07), fore-reef (near M 1 channel marker), Discovery Bay, from canals of A. clathrodes. 21 non-ovigerous individuals, 6 ovigerous females (VIMS 08JAM 4402 -09), fore-reef (near M 1 channel marker), Discovery Bay, from canals of A. cf. dispar. 4 non-ovigerous individuals, 3 ovigerous females (VIMS 08JAM6102,09,13,14,23), Columbus Park, Discovery Bay, from canals of A. cf. clathrodes. Non-ovigerous individual, ovigerous female (VIMS 08JAM6801,02), Dairy Bull Reef, from canals of A. cf. dispar. 4 nonovigerous individuals, 3 ovigerous females (VIMS 08JAM 8001 -05), wall off Rio Bueno, from canals of A. cf. dispar. Non-ovigerous individual, ovigerous female (VIMS 08JAM8101,02), wall off Rio Bueno, Jamaica, from canals of A. cf. dispar. Ovigerous female (VIMS 08JAM 8301), wall off Rio Bueno, from canals of A. cf. clathrodes. 11 non-ovigerous individuals, 7 ovigerous females (VIMS 08JAM8502,04- 10), wall off Rio Bueno, from canals of A. cf. dispar. 11 non-ovigerous individuals, 11 ovigerous females (VIMS 08JAM8904,07,11,15- 19), Columbus Park, Discovery Bay, from canals of A. cf. clathrodes. MaxCL ovigerous female: 3.78 mm. MaxCL non-ovigerous individual: 3.17 mm. Color. Bright orange overall, distal portion of major chela typically even brighter orange; embryos and ovaries are also an intense bright orange. Hosts and ecology. Synalpheus carpenteri appears to be a specialist inhabiting sponges of the genus Agelas. In Jamaica, S. carpenteri was found in large numbers, typically in relatively equal sex ratios, and was the most commonly found shrimp in both A. cf. clathrodes and A. cf. dispar. This contrasts with the situation in Belize (Macdonald et al. 2006; Rios and Duffy 2007) and Caribbean Panama (Macdonald and Duffy 2007), where S. carpenteri is less common and typically occurs as one or a few pairs per sponge. Distribution. Bahamas (as S. bousfieldi in part, Dardeau 1984; Macdonald and Duffy 2007); Caribbean Panama (Macdonald and Duffy 2006); Belize (Macdonald et al. 2006; Macdonald and Duffy 2006; Ríos and Duffy 2007); Jamaica (this study). Remarks. Synalpheus carpenteri is another member of a complex of closely related, morphologically similar species that includes S. brooksi, S. bousfieldi, S. chacei, S. corallinus n. sp., S. plumosetosus n. sp., and S. thele n. sp. (see Table 3). In life it is easily distinguishable from all other members of the complex by the intense orange color, especially the brilliant orange of the ovaries and developing embryos (see Color Plate 2 C). In preserved specimens, it can be recognized by the short, wide telson and usually by the extremely short distolateral spines of the basicerite and scaphocerite. However, two of the new species described here (S. corallinus and S. plumosetosus) also have basicerite and scaphocerite distolateral spines that rarely reach beyond the distal margin of the second segment of the antennular peduncle. Synalpheus carpenteri can be differentiated from S. corallinus by the width of the telson (telson length/proximal margin width ratio averages 0.75 in S. carpenteri and 1.19 in S. corallinus) and by the presence of a thick brush of setae on the dactyl of the minor chela (vs. two closely set, longitudinal rows of setae in S. corallinus), and from S. plumosetosus by the stouter telson (ratio of length/proximal margin width ~ 0.75 in S. carpenteri vs. ~ 1.04 in S. plumosetosus) and by the lack of plumose setae in the minor chela setal brush.Published as part of Iii, Kenneth S Macdonald, Hultgren, Kristin & Duffy, Emmett, 2009, The sponge-dwelling snapping shrimps (Crustacea, Decapoda, Alpheidae, Synalpheus) of Discovery Bay, Jamaica, with descriptions of four new species, pp. 1-57 in Zootaxa 2199 on pages 15-16, DOI: 10.5281/zenodo.18956
James Duffy, Portuguese Africa
No full textRicard Robert. James Duffy, Portuguese Africa. In: Bulletin Hispanique, tome 62, n°3, 1960. p. 353
James Duffy, Portuguese Africa
No full textRicard Robert. James Duffy, Portuguese Africa. In: Bulletin Hispanique, tome 62, n°3, 1960. p. 353
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