Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Merozoite surface protein 2 (MSP2), one of the most abundant proteins on the surface of the merozoite stage of Plasmodium falciparum, is a potential component of a malaria vaccine, having shown some efficacy in a clinical trial in Papua New Guinea. MSP2 is a GPI-anchored protein consisting of conserved N- and C-terminal domains and a variable central region. Previous studies have shown that it is an intrinsically unstructured protein with a high propensity for fibril formation, in which the conserved N-terminal domain has a key role. Secondary structure predictions suggest that MSP2 contains long stretches of random coil with very little alpha-helix or beta-strand. Circular dichroism spectroscopy confirms this prediction under physiological conditions (pH 7.4) and in more acidic solutions (pH 6.2 and 3.4). Pulsed field gradient NMR diffusion measurements showed that MSP2 under physiological conditions has a large effective hydrodynamic radius consistent with an intrinsic pre-molten globule state, as defined by Uversky. This was supported by sedimentation velocity studies in the analytical ultracentrifuge. NMR resonance assignments have been obtained for FC27 MSP2, allowing the residual secondary structure and backbone dynamics to be defined. There is some motional restriction in the conserved C-terminal region in the vicinity of an intramolecular disulfide bond. Two other regions show motional restrictions, both of which display helical structure propensities. One of these helical regions is within the conserved N-terminal domain, which adopts essentially the same conformation in full-length MSP2 as in corresponding peptide fragments. We see no evidence of long-range interactions in the full-length protein. MSP2 associates with lipid micelles, but predominantly through the N-terminal region rather than the C terminus, which is GPI-anchored to the membrane in the parasite.
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PMID:Solution conformation, backbone dynamics and lipid interactions of the intrinsically unstructured malaria surface protein MSP2. 1844 22

Decoction of Strychnopsis thouarsii is used in the Malagasy traditional medicine to combat malaria. We have shown that this traditional remedy prevents malaria infection by targeting Plasmodium at its early liver stage. Bioassay-guided fractionation of S. thouarsii stem barks extracts, using a rodent Plasmodium yoelii liver stage parasites inhibition assay, led to isolate the new morphinan alkaloid tazopsine (1) together with sinococuline (2) and two other new related morphinan analogs, 10-epi-tazopsine (3) and 10-epi-tazoside (4). Structures were characterized by 2D NMR, MS, and CD spectral analysis. Compounds 1-3 were found to fully inhibit the rodent P. yoelii liver stage parasites in vitro.
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PMID:Isolation and antimalarial activity of new morphinan alkaloids on Plasmodium yoelii liver stage. 1845 2

The emergence of multi-drug-resistant strains of Plasmodium parasites has prompted the search for alternative therapeutic strategies for combating malaria. One possible strategy is to exploit existing drugs as lead compounds. FK506 is currently used in the clinic for preventing transplant rejection. It binds to a alpha/beta protein module of approximately 120 amino acids known as the FK506 binding domain (FKBD), which is found in various organisms, including human, yeast, and Plasmodium falciparum (PfFKBD). Antiparasitic effects of FK506 and its analogues devoid of immunosuppressive activities have been demonstrated. We report here the crystallographic structure at 2.35 A resolution of PfFKBD complexed with FK506. Compared to the human FKBP12-FK506 complex reported earlier, the structure reveals structural differences in the beta5-beta6 segment that lines the FK506 binding site. The presence in PfFKBD of Cys-106 and Ser-109 (substituting for His-87 and Ile-90, respectively, in human FKBP12), which are 4-5 A from the nearest atom of the FK506 compound, suggests possible routes for the rational design of analogues of FK506 with specific antiparasitic activity. Upon ligand binding, several conformational changes occur in PfFKBD, including aromatic residues that shape the FK506 binding pocket as shown by NMR studies. A microarray analysis suggests that FK506 and cyclosporine A (CsA) might inhibit parasite development by interfering with the same signaling pathways.
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PMID:Crystal structure of the FK506 binding domain of Plasmodium falciparum FKBP35 in complex with FK506. 1846 74

We present a metabolism-driven top-down systems biology approach to characterize metabolic changes in the mouse resulting from an infection with Plasmodium berghei, using high-resolution (1)H NMR spectroscopy and multivariate data analysis techniques. Twelve female NMRI mice were infected intravenously with approximately 20 million P. berghei-parasitized erythrocytes. Urine and plasma samples were collected 4-6 h before infection, and at days 1, 2, 3, and 4 postinfection. Multivariate analysis of spectral data showed differentiation between samples collected before and after infection, with growing metabolic distinction as the time postinfection progressed. Our analysis of plasma from P. berghei-infected mice showed marked increases in lactate and pyruvate levels, and decreased glucose, creatine, and glycerophosphoryl choline compared with preinfection, indicating glycolytic upregulation, and increased energy demand due to P. berghei infection. The dominant changes in the urinary metabolite profiles included increased levels of pipecolic acid, phenylacetylglycine, and dimethylamine, and decreased concentrations of taurine and trimethylamine- N-oxide, which may, among other factors, indicate a disturbance of the gut microbial community caused by the parasite. Although several of the observed metabolic changes are also associated with other parasitic infections, the combination of metabolic changes and, in particular, the occurrence of pipecolic acid in mouse urine postinfection are unique to a P. berghei infection. Hence, metabolic profiling may provide a sensitive diagnostic tool of Plasmodium infection and the control of malaria more generally.
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PMID:Global metabolic responses of NMRI mice to an experimental Plasmodium berghei infection. 1864 85

A new tryptophan-polyketide hybrid, codinaeopsin, was isolated from an endophytic fungus collected in Costa Rica. The structure of codinaeopsin, which was deduced from NMR and mass spectral data, contains an unusual heterocyclic unit linking indole and decalin fragments. Codinaeopsin is active against Plasmodium falciparum, the causative agent of the most lethal form of malaria (IC50 = 2.3 microg/mL or 4.7 microM).
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PMID:Codinaeopsin, an antimalarial fungal polyketide. 1869 86

Quinine is the first line treatment in severe P. falciparum malaria and nocturnal leg cramps and a fast, convenient delivery method of this drug quinine is needed. The purpose of this study was to investigate in vitro the sublingual route for the delivery of quinine. Permeation studies were carried out with Franz diffusion cells containing sublingual mucosa membranes with PBS receptor phase and dosed with solutions of quinine hydrochloride or quinine/2-hydroxypropyl-beta-cyclodextrin complexes. Receptor phase samples were taken 2 hourly over a 12h period and quinine was determined by reverse-phase HPLC analysis. The ventral surface of the tongue was significantly more permeable than porcine floor of the mouth (p<0.05) and there was no significant effect of freezing on the ventral surface of the tongue (p 0.2444). The presence of saliva caused a decrease in the permeation of quinine across the ventral surface of the tongue by up to 68%. Inclusion complexation between quinine and 2-HP-beta-CD was supported by (1)H NMR spectral data, and an ethanol vehicle provided the highest quinine flux from the inclusion complex solutions compared to deionised water and PEG. Overall, the data support further investigations into the clinical use of sublingual quinine, particularly for children with falciparum malaria or patients with nocturnal leg cramps. Use of quinine/cyclodextrin inclusion complexes may circumvent compliance issues due to bitter taste.
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PMID:Permeation of quinine across sublingual mucosa, in vitro. 1883 45

Tapirira guianensis is a common tree used in traditional medicine in French Guiana against several infectious diseases (malaria, leishmaniasis, bacteria, etc.). The bioassay-guided purification of CH(2)Cl(2) bark extract led to the isolation of four cyclic alkyl polyol derivatives: 4,6,2'-trihydroxy-6-[10'(Z)-heptadecenyl]-1-cyclohexen-2-one (1a), 1,4,6-trihydroxy-1,2'-epoxy-6-[10'(Z)-heptadecenyl]-2-cyclohexene (1b), 1,4,5,2'-tetrahydroxy-1-[10'(Z)-heptadecenyl]-2-cyclohexene (2), and 1,3,4,6-tetrahydroxy-1,2'-epoxy-6-[10'(Z)-heptadecenyl]-cyclohexane (3). The structures were established on the basis of 1D and 2D NMR analyses. The anti-leishmanial, anti-plasmodial, anti-bacterial (on Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli), and anti-fungal (on Candida albicans) activities of the extracts and of these original compounds were evaluated. Two showed medicinal interest supporting the traditional uses of the plant. The structures were established through spectral analyses of the isolates and their derivatives.
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PMID:Four anti-protozoal and anti-bacterial compounds from Tapirira guianensis. 1904 89

Glycidyl methacrylate and N-vinyl-2-pyrrolidone (GMA-co-NVP) copolymers with various GMA:NVP ratios were synthesized by solution polymerization technique in toluene using 2,2'-azobisisobutyronitrile (AIBN) as free radical initiator and dip coated onto polypropylene strips. The copolymer composition in polymeric coatings was confirmed by proton NMR spectroscopy. Various techniques like FTIR, SEM and contact angle were used for surface characterization of the polymer coatings. These polymer coated strips were evaluated and standardized for their application in dot-ELISA in two steps. In first step, specificity, sensitivity and reproducibility of the assay on developed polymer coated strips was evaluated through a model system using rabbit anti-goat IgG, goat anti-rabbit IgG and goat anti-rabbit IgG HRP (horseradish peroxidase)-conjugate. Polymer coating with GMA-NVP mol% ratio of 78:22 was able to detect rabbit anti-goat IgG antibody at a concentration as low as 2 ng mL(-1) with 1% BSA as blocking agent using antispecies IgG peroxidase conjugate diluted 1500 times. In the second step, the sensitivity and specificity of the developed system was established with human blood and finally used to identify the source of mosquito blood meal which is an important parameter in epidemiological studies, particularly in determining the role of mosquito in malaria transmission. The time duration of standardized assay with developed polymer coated strips was cut down to one hour compared to the 3-4h required in usual dot-ELISA.
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PMID:Glycidyl methacrylate-co-N-vinyl-2-pyrrolidone coated polypropylene strips: synthesis, characterization and standardization for dot-enzyme linked immunosorbent assay. 1911 Jan 2

The new Ru(II) chloroquine complexes [Ru(eta(6)-arene)(CQ)Cl2] (CQ = chloroquine; arene = p-cymene 1, benzene 2), [Ru(eta(6)-p-cymene)(CQ)(H2O)2][BF4]2 (3), [Ru(eta(6)-p-cymene)(CQ)(en)][PF6]2 (en = ethylenediamine) (4), and [Ru(eta(6)-p-cymene)(eta(6)-CQDP)][BF4]2 (5, CQDP = chloroquine diphosphate) have been synthesized and characterized by use of a combination of NMR and FTIR spectroscopy with DFT calculations. Each complex is formed as a single coordination isomer: In 1-4, chloroquine binds to ruthenium in the eta(1)-N mode through the quinoline nitrogen atom, whereas in 5 an unprecedented eta(6) bonding through the carbocyclic ring is observed. 1, 2, 3, and 5 are active against CQ-resistant (Dd2, K1, and W2) and CQ-sensitive (FcB1, PFB, F32, and 3D7) malaria parasites (Plasmodium falciparum); importantly, the potency of these complexes against resistant parasites is consistently higher than that of the standard drug chloroquine diphosphate. 1 and 5 also inhibit the growth of colon cancer cells, independently of the p53 status and of liposarcoma tumor cell lines with the latter showing increased sensitivity, especially to 1 (IC50 8 microM); this is significant because this type of tumor does not respond to currently employed chemotherapies.
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PMID:Synthesis, characterization, and in vitro antimalarial and antitumor activity of new ruthenium(II) complexes of chloroquine. 1911 67

Bromophycolides J-Q (1-8) were isolated from extracts of the Fijian red alga Callophycus serratus and identified with 1D and 2D NMR spectroscopy and mass spectral analyses. These diterpene-benzoate macrolides represent two novel carbon skeletons and add to the 10 previously reported bromophycolides (9-18) from this alga. Among these 18 bromophycolides, several exhibited activities in the low micromolar range against the human malaria parasite Plasmodium falciparum.
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PMID:Antimalarial bromophycolides J-Q from the Fijian red alga Callophycus serratus. 1927 27


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