| are antibodies important in mice infected with plasmodium yoelii? | it is unwise to extrapolate results, even from one mouse strain to another, when attempting to define the mechanisms that control and effect anti-malaria immunity. it is important to better characterize the broad range o f possible responses that are likely to occur when individuals in an outbred population are infected. here, peter sayles and donald wossom discuss briefly their views on the role of antibody in murine and human malaria infections, based on their work on mice infected with plasmo ... | 1992 | 15463543 |
| are antibodies important in mice infected with plasmodium yoelii? | | 1993 | 15463719 |
| synthesis of new 6-alkylvinyl/arylalkylvinyl substituted 1,2,4-trioxanes active against multidrug-resistant malaria in mice. | 3-alkyl/arylalkyl substituted 2-butenols 9, 10, 23a-d undergo regiospecific photooxygenation to furnish beta-hydroxyhydroperoxides 11, 12, 24a-d, respectively, in reasonable yields. acid catalyzed condensation of 11, 12, 24a-d with various ketones furnish new 1,2,4-trioxanes 13-18, 25a-d, 26a-d, 27a-d in good yields. several of these trioxanes show promising antimalarial activity against multidrug-resistant plasmodium yoelii in mice by oral and intramuscular routes. | 2004 | 15465332 |
| a protective merozoite protein of plasmodium falciparum shares an epitope with surface antigens of paramecium. | a plasmodium falciparum cdna expression clone, lambdapf9, had been identified earlier as a protective epitope, using anti-lambdapf9 antibodies and combinatorial phagotopes. a segment of the pf9 gene showed homology with paramecium immobilization surface antigens such as 51b, 51a and 156g. a synthetic pf9-peptide was designed from this region, and specific antibodies were raised. each of these anti-pf9 antibodies and combinatorial reagents, as well as anti-paramecium 51b antibodies, recognized th ... | 2004 | 15491471 |
| synthesis and antimalarial activity of 6-cycloalkylvinyl substituted 1,2,4-trioxanes. | 6-cycloalkylvinyl substituted 1,2,4-trioxanes 6-15 have been prepared and tested against multi-drug resistant plasmodium yoelii in mice. the most active trioxane 11 provides 80% protection to the treated mice. further derivatization of 11 leads to decrease in antimalarial activity. | 2004 | 15498651 |
| plasmodium falciparum carbonic anhydrase is a possible target for malaria chemotherapy. | plasmodiumfalciparum is responsible for the majority of life-threatening cases of human malaria. the global emergence of drug-resistant malarial parasites necessitates identification and characterization of novel drug targets. carbonic anhydrase (ca) is present at high levels in human red cells and in p. falciparum. existence of at least three isozymes of the alpha < class was demonstrated in p. falciparum and a rodent malarial parasite plasmodium berghei. the major isozyme ca1 was purified and ... | 2004 | 15499996 |
| plasmodium vivax merozoite surface protein 8 cloning, expression, and characterisation. | plasmodium vivax, one of the four parasite species causing malaria in humans, is the most widespread throughout the world, leading to nearly 80 million cases per year, mainly in latin-america and asia. an open reading frame encoding the plasmodium falciparum merozoite surface protein 8 p. vivax homologue has been identified in the present study by screening the current data obtained from this parasite's partially sequenced genome. this new protein contains 487 amino-acids, two epidermal growth f ... | 2004 | 15504368 |
| blue skies or stormy weather: what lies ahead for malaria research? | during the past ten years, our understanding of many aspects of the biology of malaria parasites has increased dramatically. in particular, the complete genome sequences of plasmodium falciparum and plasmodium yoelii, the availability of transcriptome and proteome profiles, and the establishment of transfection techniques for asexual-stage malaria parasites all represent major achievements from the past decade. now that we are truly in the post-genomic phase of biological enquiry, this article h ... | 2004 | 15522672 |
| immunogenicity of polyepitope libraries assembled by epitope shuffling: an approach to the development of chimeric gene vaccination against malaria. | developing a polyepitope vaccine which contains diverse antigenic types is a promising strategy to cope with the problem of malaria variation and diversity. however, arranging the peptides to produce the most effective immunogenicity remains a hurdle. in an attempt to develop an effective complex antigenic gene vaccine, we constructed a polyepitope library by randomly assembling epitopes using the epitope shuffling technique. the polyepitope library, which contains epitopes from different antige ... | 2004 | 15531046 |
| co-infection of malaria and gamma-herpesvirus: exacerbated lung inflammation or cross-protection depends on the stage of viral infection. | in order to study the interaction between a gamma-herpesvirus and malaria we established a co-infection model that involves infection of mice with murine gamma-herpesvirus (mhv-68) and plasmodium yoelii non-lethal strain (pynl). to investigate the interaction between acute malaria and the lytic stage of mhv-68, the timing of infections was chosen such that the peak virus and parasite burdens would be present at the same time. under this condition, we observed significant mortality in co-infected ... | 2004 | 15544614 |
| alternative mechanism of eimeria bovis sporozoites to invade cells in vitro by breaching the plasma membrane. | in vitro eimeria bovis sporozoites invade a wide range of cell types, and in the case of bovine cells, they may develop to first-generation schizonts. often, however, they subsequently leave their host cell to invade a new one, which seems contrary to the classical way of infecting a cell by forming a parasitophorous vacuole. using a standard, "cell wound assay," we show that e. bovis can invade bovine endothelial cells by breaching the plasma membrane and may again leave the surviving cell. eim ... | 2004 | 15562619 |
| the genome of model malaria parasites, and comparative genomics. | the field of comparative genomics of malaria parasites has recently come of age with the completion of the whole genome sequences of the human malaria parasite plasmodium falciparum and a rodent malaria model, plasmodium yoelii yoelii. with several other genome sequencing projects of different model and human malaria parasite species underway, comparing genomes from multiple species has necessitated the development of improved informatics tools and analyses. results from initial comparative anal ... | 2005 | 15580778 |
| cloning, over-expression, purification and characterization of plasmodium falciparum enolase. | we have cloned, over-expressed and purified enolase from plasmodium falciparum strain nf54 in escherichia coli in active form, as an n-terminal his6-tagged protein. the sequence of the cloned enolase from the nf54 strain is identical to that of strain 3d7 used in full genome sequencing. the recombinant enolase (r-pfen) could be obtained in large quantities (approximately 50 mg per litre of culture) in a highly purified form (> 95%). the purified protein gave a single band at approximately 50 kda ... | 2004 | 15606772 |
| a comprehensive survey of the plasmodium life cycle by genomic, transcriptomic, and proteomic analyses. | plasmodium berghei and plasmodium chabaudi are widely used model malaria species. comparison of their genomes, integrated with proteomic and microarray data, with the genomes of plasmodium falciparum and plasmodium yoelii revealed a conserved core of 4500 plasmodium genes in the central regions of the 14 chromosomes and highlighted genes evolving rapidly because of stage-specific selective pressures. four strategies for gene expression are apparent during the parasites' life cycle: (i) housekeep ... | 2005 | 15637271 |
| yellow fever 17d as a vaccine vector for microbial ctl epitopes: protection in a rodent malaria model. | the yellow fever vaccine 17d (17d) is safe, and after a single immunizing dose, elicits long-lasting, perhaps lifelong protective immunity. one of the major challenges facing delivery of human vaccines in underdeveloped countries is the need for multiple injections to achieve full efficacy. to examine 17d as a vector for microbial t cell epitopes, we inserted the h-2k(d)-restricted ctl epitope of the circumsporozoite protein (cs) of plasmodium yoelii between 17d nonstructural proteins ns2b and n ... | 2005 | 15657290 |
| erythrocyte surface glycosylphosphatidyl inositol anchored receptor for the malaria parasite. | parasitophorous vacuole formation is a critical step for the successful invasion of host erythrocytes by the malaria parasite. rhoptry proteins are believed to have essential roles in vacuole formation, although their biological roles are poorly understood. to understand the molecular interactions between parasite rhoptry proteins and the erythrocyte during invasion, we have characterized the binding specificity of the high molecular mass rhoptry protein (rhoph) complex to erythrocytes using the ... | 2005 | 15694483 |
| an aflp-based genetic linkage map of plasmodium chabaudi chabaudi. | plasmodium chabaudi chabaudi can be considered as a rodent model of human malaria parasites in the genetic analysis of important characters such as drug resistance and immunity. despite the availability of some genome sequence data, an extensive genetic linkage map is needed for mapping the genes involved in certain traits. | 2005 | 15707493 |
| plasmodium yoelii: a differential fluorescent technique using acridine orange to identify infected erythrocytes and reticulocytes in duffy knockout mouse. | both human malarial parasite plasmodium vivax and mouse malaria parasite plasmodium yoelii use duffy protein as the receptor for invasion and they preferentially invade reticulocytes. recently, it has been shown that p. yoelii invades mouse reticulocytes by a duffy independent pathway. parasite invasion is generally visualized by time consuming staining procedures with dyes like giemsa or wright-giemsa. fluorochromatic dye like acridine orange has been used for instantaneous detection of parasit ... | 2005 | 15804382 |
| evaluation of french guiana traditional antimalarial remedies. | in order to evaluate the antimalarial potential of traditional remedies used in french guiana, 35 remedies were prepared in their traditional form and screened for blood schizonticidal activity in vitro on plasmodium falciparum chloroquine re4sistant strain (w2). some of these extracts were screened in vivo against plasmodium yoelii rodent malaria. ferriprotoporphyrin inhibition test was also performed. four remedies, widely used among the population as preventives, were able to inhibit more tha ... | 2005 | 15849870 |
| transcriptional analysis of in vivo plasmodium yoelii liver stage gene expression. | the transcriptional repertoire of the in vivo liver stage of plasmodium has remained largely unidentified and seemingly not amenable to traditional molecular analysis because of the small number of parasites and large number of uninfected hepatocytes. we have overcome this obstruction by utilizing laser capture microdissection to provide a high quality source of parasite mrna for the construction of a liver stage cdna library. sequencing and annotation of this library demonstrated expression of ... | 2005 | 15876462 |
| cutting edge: the acquisition of tlr tolerance during malaria infection impacts t cell activation. | an effective immune response to infection requires control of pathogen growth while minimizing inflammation-associated pathology. during malaria infection, this balance is particularly important. murine malaria is characterized by early production of proinflammatory cytokines, which declines in the face of continuing parasitemia. the mechanism by which this occurs remains poorly understood. in this study, we investigated the role of dendritic cells (dcs) in regulating pro- and anti-inflammatory ... | 2005 | 15879082 |
| fas has a role in cerebral malaria, but not in proliferation or exclusion of the murine parasite in mice. | we examined the susceptibility of murine fas-deficient mutants to malaria infection in order to investigate the role of fas in an experimental murine model of cerebral malaria (cm). we infected mice of b6 and cba wild-type and mutant backgrounds with plasmodium berghei anka. the incidence of cm in the mutant mice (b6-lpr, cba-lprcg) was decreased by about 50% compared with wild-type control strains at 2 weeks after infection. we did not observe significant differences of parasitemia during a mur ... | 2005 | 15900502 |
| insights into the p. y. yoelii hepatic stage transcriptome reveal complex transcriptional patterns. | during their complex life cycle, malaria parasites adopt morphologically, biochemically and immunologically distinct forms. the intra-hepatic form is the least known, yet of established value in the induction of sterile immunity and as a target for chemoprophylaxis. using plasmodium yoelii as a model we present here a novel approach to the elucidation of the transcriptome of this poorly studied stage. sequences from plasmodium were obtained in 388 of the 3533 inserts (11%) isolated from liver st ... | 2005 | 15913805 |
| malaria parasite developmental analyses by the nested polymerase chain reaction method: an implication for the evaluation of mosquito infection rates in epidemiological studies. | a malaria mosquito vector, anopheles saperoi, and a non-vector, aedes albopictus, were allowed to feed on mice infected with murine malaria, plasmodium yoelii nigeriensis, and were subsequently monitored for the development of parasites by the nested polymerase chain reaction (pcr) method, using plasmodium genus-specific primer pairs. the mosquitos were divided into two parts, head/thorax and abdomen, for dna analyses. the parasite dna and murine dna for each mosquito were examined in parallel. ... | 2004 | 15916075 |
| influence of glycosylphosphatidylinositol anchorage on the efficacy of dna vaccines encoding plasmodium yoelii merozoite surface protein 4/5. | immune responses induced to dna vaccination vary considerably and depend on a variety of factors, including the physical form in which the antigen is expressed by target cells and presented to the immune system. data on the effect of these factors will aid improved design of dna vaccines and facilitate their further development. we examined the effect of different forms of surface anchoring on the immunogenicity of a dna vaccine. a number of constructs were generated encoding plasmodium yoelii m ... | 2005 | 15964480 |
| quantitative dynamics of plasmodium yoelii sporozoite transmission by infected anopheline mosquitoes. | malaria transmission begins with the injection of plasmodium sporozoites into the skin of a vertebrate host by infected anopheline mosquitoes. although the size of the sporozoite inoculum likely affects the course of the disease, the number of sporozoites injected by infected mosquitoes has not been determined in vivo. using a quantitative pcr assay, we determined the number of sporozoites injected into mice by single mosquitoes. analysis of 59 mosquito feedings showed that a single infected mos ... | 2005 | 15972531 |
| amino acid sequence constraint and gene expression pattern across the life history in the malaria parasite plasmodium falciparum. | the relationship between gene expression across the life cycle and protein conservation in plasmodium falciparum was examined by comparing gene expression data for six life-history stages with the number of nonsynonymous substitutions per site dn between 901 orthologous gene pairs of p. falciparum and plasmodium yoelii. a high level of expression across the life history was associated with decreased dn and thus with protein conservation. by contrast, differential expression in the sporozoite and ... | 2005 | 15978954 |
| phagocyte-derived reactive oxygen species do not influence the progression of murine blood-stage malaria infections. | phagocyte-derived reactive oxygen species have been implicated in the clearance of malaria infections. we investigated the progression of five different strains of murine malaria in gp91(phox-/-) mice, which lack a functional nadph oxidase and thus the ability to produce phagocyte-derived reactive oxygen species. we found that the absence of functional nadph oxidase in the gene knockout mice had no effect on the parasitemia or total parasite burden in mice infected with either resolving (plasmod ... | 2005 | 16041008 |
| plasmodium yoelii can ablate vaccine-induced long-term protection in mice. | malaria is a serious cause of morbidity and mortality for people living in endemic areas, but unlike many other infections, individuals exposed to the parasite do not rapidly become resistant to subsequent infections. high titers of ab against the 19-kda c-terminal fragment of the merozoite surface protein-1 can mediate complete protection in model systems; however, previous studies had not determined whether this vaccine generated long-term protection. in this study, we report that functional m ... | 2005 | 16081823 |
| improvement of detection specificity of plasmodium-infected murine erythrocytes by flow cytometry using autofluorescence and yoyo-1. | microscopic analysis of blood smears is currently the most frequently used method to measure parasitemias in experiments of drug efficacy in murine models of malaria. however, it is subjective and labour intensive, which preclude its utilization in large-scale evaluation programs. flow cytometry is an alternative method, but due to the limited specificity achieved with the currently available techniques, it has not been widely used in murine models of malaria during preclinical evaluation. we de ... | 2005 | 16082714 |
| il-4 receptor expression on cd8+ t cells is required for the development of protective memory responses against liver stages of malaria parasites. | il-4 receptor (il-4r)-deficient cd8+ t cells specific for the circumsporozoite protein of plasmodium yoelii develop a severely impaired memory response after priming with parasites. memory cd8+ t cells lacking the il-4r are unable to establish a stable population residing in nonlymphoid organs, although they develop normally in lymphoid organs. because memory cells from nonlymphoid organs disappear shortly after immunization, the protective antiparasitic activity of this t cell response also is ... | 2005 | 16087712 |
| identification, cloning, expression, and characterization of the gene for plasmodium knowlesi surface protein containing an altered thrombospondin repeat domain. | proteins present on the surface of malaria parasites that participate in the process of invasion and adhesion to host cells are considered attractive vaccine targets. aided by the availability of the partially completed genome sequence of the simian malaria parasite plasmodium knowlesi, we have identified a 786-bp dna sequence that encodes a 262-amino-acid-long protein, containing an altered version of the thrombospondin type i repeat domain (spatr). thrombospondin type 1 repeat domains particip ... | 2005 | 16113256 |
| genome-wide expression profiling in malaria infection reveals transcriptional changes associated with lethal and nonlethal outcomes. | high-density oligonucleotide microarrays are widely used to study gene expression in cells exposed to a variety of pathogens. this study addressed the global genome-wide transcriptional activation of genes in hosts infected in vivo, which result in radically different clinical outcomes. we present an analysis of the gene expression profiles that identified a set of host biomarkers which distinguish between lethal and nonlethal blood stage plasmodium yoelii malaria infections. multiple biological ... | 2005 | 16113330 |
| a mathematical model for a new mechanism of phenotypic variation in malaria. | the py235 merozoite rhoptry protein of the rodent malaria agent plasmodium (yoelii) yoeli is encoded by the py235 multigene family whose members are transcribed during the parasite's asexual life-cycle in a fashion where single schizonts subsequently give rise to sets of merozoites containing distinct py235 transcripts. homologues of py235 are found in other malaria species, and antibodies to both py235 and p. falciparum homologues inhibit merozoite invasion, suggesting a unique survival strateg ... | 2005 | 16145932 |
| escheriosome entrapped soluble blood stage antigens impart protective immunity against a multi-drug resistant isolate of plasmodium yoelii nigeriensis in balb/c mice. | the plasmodium yoelii nigeriensis murine model was used to evaluate the potential of liposome entrapped soluble blood stage antigens (sag) based vaccine against malaria infection in balb/c mice. results from the present study revealed that immunization with e. coli lipid liposome (escheriosome) entrapped sag provided strong protective immune responses that successfully suppressed drug resistant strain of plasmodium yoelii, whereas other forms of sag such as, egg pc/chol liposomes entrapped, or i ... | 2006 | 16168527 |
| detection of plasmodium falciparum in pregnancy by laser desorption mass spectrometry. | detection of plasmodium falciparum malaria during pregnancy is complicated by sequestration of parasites in the placenta, which reduces peripheral blood microscopic detection. laser desorption mass spectrometry (ldms) has previously demonstrated sensitive detection of hemozoin from p. falciparum blood cultures and the ability to track parasitemia in a plasmodium yoelii malaria mouse model. here we use a simple, dilution in water, blood sample preparation protocol for ldms detection of malaria in ... | 2005 | 16172468 |
| alteration in host cell tropism limits the efficacy of immunization with a surface protein of malaria merozoites. | immunization with plasmodium yoelii merozoite surface protein-8 (pymsp-8) has been shown to protect mice against lethal p. yoelii 17xl malaria. here we demonstrate that pymsp-8-specific antibodies preferentially suppress p. yoelii 17xl growth in mature erythrocytes compared to growth in reticulocytes and do not suppress the growth of nonlethal p. yoelii 17x, a parasite that primarily replicates in reticulocytes. the protection against normocyte-associated p. yoelii malaria parasites is mediated ... | 2005 | 16177307 |
| blood schizontocidal activity of azithromycin and its combination with alpha/beta arteether against multi-drug resistant plasmodium yoelii nigeriensis, a novel mdr parasite model for antimalarial screening. | many different drug-resistant lines of rodent malaria are available as screening models. it is obligatory to screen new compounds for antimalarial activity against a series of resistant lines in order to identify a compound with potential for the treatment of multi-drug resistant (mdr) malaria infections. instead of using a battery of resistant lines, a single mdr plasmodium yoelii nigeriensis strain that shows a wide spectrum of drug resistance to high doses of chloroquine, mepacrine, amodiaqui ... | 2005 | 16178350 |
| unambiguous synthesis and prophylactic antimalarial activities of imidazolidinedione derivatives. | wr182393, a guanidinoimidazolidinedione derivatives with potent causal prophylactic antimalarial activity by intramuscular injection, was previously prepared by treatment of chloroproguanil and diethyl oxalate, yielding a mixture of two closely related isomers. poor solubility of the mixture made the separation and purification impossible. to overcome the separation problem, new and facile unambiguous syntheses of the two active components were reported. the new synthetic methods facilitate the ... | 2005 | 16190773 |
| immune stimulation and malaria infection impose reproductive costs in anopheles gambiae via follicular apoptosis. | the employment of defense mechanisms is recognized as a costly life-history trait. in the malaria vector anopheles gambiae, reproductive costs have been associated with both humoral and cellular innate immune responses and also with malaria infection. the resorption of developing oocytes associated with malaria infection is preceded by the programmed cell death, or apoptosis, of follicular cells. here we demonstrate that apoptosis in ovarian follicular epithelial cells also occurs when mosquitoe ... | 2006 | 16213176 |
| antimalarial efficacy of methylene blue and menadione and their effect on glutathione metabolism of plasmodium yoelii-infected albino mice. | plasmodium yoelii infection caused significant decline in the hepatic and splenic glutathione content and the activities of the key enzymes, that is, glutamate cysteine ligase (ec 6.3.2.2) and glutathione reductase (ec 1.8.1.7) of their murine host, that is, swiss albino mice. methylene blue as well as menadione were found to restore these constituents when given to p. yoelii-infected mice at the dose levels of 2.5 and 100 mg/kg, respectively, compared to mefloquine which does the same at 5.0 mg ... | 2005 | 16217669 |
| host immunity modulates transcriptional changes in a multigene family (yir) of rodent malaria. | variant antigens, encoded by multigene families, and expressed at the surface of erythrocytes infected with the human malaria parasite plasmodium falciparum and the simian parasite plasmodium knowlesi, are important in evasion of host immunity. the vir multigene family, encoding a very large number of variant antigens, has been identified in the human parasite plasmodium vivax and homologues (yir) of this family exist in the rodent parasite plasmodium yoelii. these genes are part of a superfamil ... | 2005 | 16238615 |
| protection against malaria by anti-erythropoietin antibody due to suppression of erythropoiesis in the liver and at other sites. | we have previously reported that erythropoiesis commences in the liver and spleen after malarial infection, and that newly generated erythrocytes in the liver are essential for infection of malarial parasites as well as continuation of infection. at this time, erythropoietin (epo) is elevated in the serum. in the present study, we administered epo or anti-epo antibody into c57bl/6 (b6) mice to modulate the serum level of epo. when mice were infected with a non-lethal strain (17nxl) of plasmodium ... | 2005 | 16266316 |
| 8-(1-naphthalen-2-yl-vinyl)-6,7,10-trioxaspiro (4.5) decane, a new 1,2,4-trioxane effective against rodent and simian malaria. | a new series of 8-(1-aryl-vinyl)-6,7,10-trioxaspiro [4.5] decanes 7a-e and 3-(1-aryl-vinyl)-l,2,5-trioxaspiro [5.5] undecanes 8a-e have been prepared and screened against multi-drug resistant plasmodium yoelii in mice. 8-(1-naphthalen-2-yl-vinyl)-6,7,10-trioxaspiro [4.5] decane 7b, the most active trioxane of the series, has also shown promising activity against plasmodium cynomolgi in rhesus monkeys. | 2006 | 16275088 |
| plasmodium yoelii: axenic development of the parasite mosquito stages. | study of the parasite mosquito stages of plasmodium and its use in the production of sporozoite vaccines against malaria has been hampered by the technical difficulties of in vitro development. here, we show the complete axenic development of the parasite mosquito stages of plasmodium yoelii. while we demonstrate that matrigel is not required for parasite development, soluble factors produced and secreted by drosophila melanogaster s2 cells appear to be crucial for the ookinete to oocyst transit ... | 2006 | 16289466 |
| vaxfectin enhances immunogenicity and protective efficacy of p. yoelii circumsporozoite dna vaccines. | we evaluated the capacity of the cationic lipid based formulation, vaxfectin, to enhance the immunogenicity and protective efficacy of dna-based vaccine regimens in the plasmodium yoelii murine malaria model. we immunized balb/c mice with varying doses (0.4-50 microg) of plasmid dna (pdna) encoding the p. yoelii circumsporozoite protein (pycsp), either in a homologous dna/dna regimen (d-d) or a heterologous prime-boost dna-poxvirus regimen (d-v). at the lowest pdna doses, vaxfectin substantially ... | 2006 | 16298024 |
| mycobacterium-induced potentiation of type 1 immune responses and protection against malaria are host specific. | malaria and tuberculosis are endemic in many regions of the world, and coinfection with the two pathogens is common. in this study, we examined the effects of long- and short-term infection with mycobacterium tuberculosis on the course of a lethal form of murine malaria in resistant (c57bl/6) and susceptible (balb/c) mice. c57bl/6 mice coinfected with m. tuberculosis cdc1551 and plasmodium yoelii 17xl had a lower peak parasitemia and increased survival compared to mice infected with p. yoelii 17 ... | 2005 | 16299335 |
| antimalarial activities of new pyrrolo[3,2-f]quinazoline-1,3-diamine derivatives. | wr227825 is an antimalarial pyrroloquinazolinediamine derivative with a high potency but a low therapeutic index. a series of carbamate, carboxamide, succinimide, and alkylamine derivatives of wr227825 were prepared to search for compounds with an improved therapeutic index. the new acetamides and imide showed potent cell growth inhibition against four clones of plasmodium falciparum (d-6, rcs, w-2, and tm91c235), with a 50% inhibitory concentration of approximately 0.01 ng/ml, and were highly a ... | 2005 | 16304154 |
| resistance of regulatory t cells to glucocorticoid-induced [corrected] tnfr family-related protein (gitr) during plasmodium yoelii infection. | cd4+ t cells are the major effector t cells against blood-stage plasmodium yoelii infection. on the other hand, the lethal strain of p. yoelii (pyl) has acquired an escape mechanism from host t cell immunity by activating cd4+cd25+ regulatory t cells (treg). although the activation of treg during pyl infection precludes the clearance of pyl from mice, it remains unclear whether activation of treg is attributable to a specific response against pyl infection. thus, we examined here whether treg pr ... | 2005 | 16304635 |
| plasmodium falciparum trythra antigen synthetic peptides block in vitro merozoite invasion to erythrocytes. | tryptophan-threonine-rich antigen (trythra) is a plasmodium falciparum homologue of plasmodium yoelii-infected erythrocyte membrane pypag-1 antigen. pypag-1 binds to the surface of uninfected mouse erythrocytes and has been used successfully in vaccine studies. the two antigens are characterized by an unusual tryptophan-rich domain, suggesting similar biological properties. using synthetic peptides spanning the trythra sequence and human erythrocyte we have done binding assays to identify possib ... | 2006 | 16329993 |
| the mtip-myosin a complex in blood stage malaria parasites. | parasites of the apicomplexa phylum use an actomyosin motor to drive invasion of host cells. the motor complex is located at the parasite's periphery between the plasma membrane and an inner membrane complex. a crucial component of this complex is myosin tail domain interacting protein (mtip) identified in the murine malaria parasite plasmodium yoelii. here, we show that mtip is expressed in plasmodium falciparum merozoites, localises to the periphery of the cell and is present in a complex with ... | 2006 | 16337961 |
| plasmodium yoelii 17xl infection up-regulates rantes, ccr1, ccr3 and ccr5 expression, and induces ultrastructural changes in the cerebellum. | malaria afflicts 300-500 million people causing over 1 million deaths globally per year. the immunopathogenesis of malaria is mediated partly by co mplex cellular and immunomodulator interactions involving co-regulators such as cytokines and adhesion molecules. however, the role of chemokines and their receptors in malaria immunopathology remains unclear. rantes (regulated on activation normal t-cell expressed and secreted) is a chemokine involved in the generation of inflammatory infiltrates. r ... | 2005 | 16359553 |
| immunogenicity and protection of a recombinant human adenovirus serotype 35-based malaria vaccine against plasmodium yoelii in mice. | given the promise of recombinant adenovirus type 5 (rad5) as a malaria vaccine carrier in preclinical models, we evaluated the potency of rad35 coding for plasmodium yoelii circumsporozoite protein (rad35pycs). we chose rad35 since a survey with serum samples from african subjects demonstrated that human ad35 has a much lower seroprevalence of 20% and a much lower geometric mean neutralizing antibody titer (gmt) of 48 compared to ad5 (seroprevalence, 85%; gmt, 1,261) in countries with a high mal ... | 2006 | 16368986 |
| the domain on the mouse duffy protein for plasmodium yoelii binding and invasion to mouse erythrocytes. | erythrocyte invasion by malaria parasites is a multi-step process requiring specific molecular interactions between merozoites and erythrocyte surface receptors. human duffy blood group protein is the receptor for plasmodium vivax merozoite invasion to red blood cells. the cognate parasite ligand for duffy protein is a 135 kda duffy binding protein (dbp). previously, we defined the domain on the n-terminus of human duffy protein required for dbp binding and showed that a 35-mer n-terminal peptid ... | 2006 | 16386320 |
| reasons why dba/2 mice are resistant to malarial infection: expansion of cd3int b220+ gammadelta t cells with double-negative cd4- cd8- phenotype in the liver. | dba/2 (h-2(d)) mice are known to be more resistant than c57bl/6 (b6, h-2(b)) mice to the non-lethal 17xnl strain of plasmodium yoelii. this is a very strange phenomenon because the functions of conventional t cells, especially cd8(+) t cells, are known to be somewhat lower in dba/2 mice than in other strains of mice. we examined herein how immune responses differed between dba/2 mice and b6 mice during malarial infection. dba/2 mice and (dba/2 x b6)f(1) (bdf(1), h-2(b/d)) mice were found to have ... | 2006 | 16423048 |
| oral vaccination of mice against rodent malaria with recombinant lactococcus lactis expressing msp-1(19). | to construct the recombinant lactococcus lactis as oral delivery vaccination against malaria. | 2005 | 16437602 |
| improved transfection and new selectable markers for the rodent malaria parasite plasmodium yoelii. | the rodent malaria plasmodium yoelii is a useful model to study protective immunity to pre-erythrocytic stages of infection, pathogenesis of erythrocytic stages, and vaccine development. however, the utility of the p. yoelii model system has not been fully realized because transfection and genetic manipulation methodologies for this rodent species are less developed than that of another rodent species plasmodium berghei. here we report improved transfection efficiency using the amaxa nucleofecto ... | 2006 | 16458371 |
| isolation and characterization of type i signal peptidase of different malaria parasites. | type i signal peptidases are important membrane-bound serine proteases responsible for the cleavage of the signal peptide of the proteins. these enzymes are unique serine proteases that carry out catalysis using a serine/lysine catalytic dyad. in the present study, we report the isolation of type i signal peptidase from the malaria parasites plasmodium falciparum, plasmodium knowlesi, and plasmodium yoelii and some characterization of type i signal peptidase of plasmodium falciparum. we show tha ... | 2005 | 16489263 |
| antigen targeting to dendritic cells elicits long-lived t cell help for antibody responses. | resistance to several prevalent infectious diseases requires both cellular and humoral immune responses. t cell immunity is initiated by mature dendritic cells (dcs) in lymphoid organs, whereas humoral responses to most antigens require further collaboration between primed, antigen-specific helper t cells and naive or memory b cells. to determine whether antigens delivered to dcs in lymphoid organs induce t cell help for antibody responses, we targeted a carrier protein, ovalbumin (ova), to dcs ... | 2006 | 16505139 |
| a member of the py235 gene family of plasmodium yoelii encodes an erythrocyte binding protein recognised by a protective monoclonal antibody. | | 2006 | 16516987 |
| computational modeling of the plasmodium falciparum interactome reveals protein function on a genome-wide scale. | many thousands of proteins encoded by the genome of plasmodium falciparum, the causal organism of the deadliest form of human malaria, are of unknown function. it is of utmost importance that these proteins be characterized if we are to develop combative strategies against malaria based on the biology of the parasite. in an attempt to infer protein function on a genome-wide scale, we computationally modeled the p. falciparum interactome, elucidating local and global functional relationships betw ... | 2006 | 16520460 |
| evaluating the costs of mosquito resistance to malaria parasites. | costly resistance mechanisms have been cited as an explanation for the widespread occurrence of parasitic infections, yet few studies have examined these costs in detail. a malaria-mosquito model has been used to test this concept by making a comparison of the fitness of highly susceptible lines of mosquitoes with lines that are resistant to infection. malaria infection is known to cause a decrease in fecundity and fertility of mosquitoes; resistant mosquitoes were thus predicted to be fitter th ... | 2005 | 16526504 |
| rhop-3 protein conservation among plasmodium species and induced protection against lethal p. yoelii and p. berghei challenge. | in the present study, rhop-3 polymorphism among plasmodium falciparum field and laboratory isolates and among rodent plasmodium species was investigated and identified. the rhop-3 gene was found in all plasmodium species so far tested. the overall structure of the rhop-3 protein was found conserved among p. falciparum, plasmodium yoelii, and plasmodium berghei. however, it was more conserved among rodent plasmodium species than between p. falciparum and plasmodium vivax. the most conserved regio ... | 2006 | 16541261 |
| protective cd8+ t cells induced by malaria sporozoites do not undergo modulation of interleukin-7 receptor expression. | cd8+ t cells induced by plasmodium yoelii sporozoites develop into protective memory cells without undergoing changes in interleukin-7 receptor alpha (il-7ralpha) expression, differing from the development of memory cd8+ t cells against viruses, which is associated with enhanced il-7ralpha expression. this suggests a microbe-dependent diversity in the signals determining the development of memory populations. | 2006 | 16552087 |
| [cloning, location and differential analysis of transcription factor relish gene from anopheles stephensi under different feeding conditions]. | to clone, locate and differentially analyze the transcription factor relish gene from anopheles stephensi, and to examine its signals-modulating action on prophenoloxidase cascade and melanization of plasmodium yoelii oocysts. | 2005 | 16562473 |
| two serine proteases from anopheles dirus haemocytes exhibit changes in transcript abundance after infection of an incompatible rodent malaria parasite, plasmodium yoelii. | serine proteases are involved in regulation of innate immune responses, such as haemolymph coagulation, melanization reaction and antimicrobial peptide synthesis. although several serine proteases have been characterized in anopheles gambiae (a. gambiae), few were cloned from other malaria vectors. in this study, we identified three cdna fragments of serine proteases (adsp1, adsp2 and adsp3) from haemocytes of an oriental malaria vector, anopheles dirus (a. dirus), by cloning of fragments amplif ... | 2006 | 16567047 |
| using green fluorescent malaria parasites to screen for permissive vector mosquitoes. | the plasmodium species that infect rodents, particularly plasmodium berghei and plasmodium yoelii, are useful to investigate host-parasite interactions. the mosquito species that act as vectors of human plasmodia in south east asia, africa and south america show different susceptibilities to infection by rodent plasmodium species. p. berghei and p. yoelii infect both anopheles gambiae and anopheles stephensi, which are found mainly in africa and asia, respectively. however, it was reported that ... | 2006 | 16569221 |
| studies on drug metabolizing enzymes during arteether treatment of plasmodium yoelii nigeriensis infected mice cerebral microvessels. | human cerebral malaria is caused by a protozoan parasitic with no cure till date. the isolation of brain capillaries i.e. microvessels has permitted the in vitro study related to cerebral function. microvessels were isolated from normal and p. yoelii infected mice brain cortex and subjected to biochemical characterization by the following enzyme markers viz alkaline phosphatase, gamma-glutamyi transpeptidase and monoamine oxidase and electron microscopically. limited studies have been carried ou ... | 2005 | 16637400 |
| orally active 1,2,4-trioxanes: synthesis and antimalarial assessment of a new series of 9-functionalized 3-(1-arylvinyl)-1,2,5-trioxaspiro[5.5]undecanes against multi-drug-resistant plasmodium yoelii nigeriensis in mice. | using easily accessible keto-trioxanes 7a-g as the starting materials, a series of new variously functionalized 1,2,4-trioxanes 10-36 have been prepared and evaluated for antimalarial activity against multi-drug-resistant plasmodium yoelii nigeriensis in mice in the dose range of 24 mg/kg x 4 days to 96 mg/kg x 4 days by oral route. trioxanes 10, 12, 14, 16, 18, 20, and 22 have shown promising antimalarial activity. trioxanes 14 and 18, the two most active compounds of the series, provide 100% a ... | 2006 | 16640340 |
| cholesterol contributes to the organization of tetraspanin-enriched microdomains and to cd81-dependent infection by malaria sporozoites. | tetraspanins constitute a family of widely expressed integral membrane proteins that associate extensively with one another and with other membrane proteins to form specific membrane microdomains distinct from conventional lipid rafts. so far, because of the lack of appropriate tools, the functionality of these microdomains has remained largely unknown. here, using a new monoclonal antibody that only binds to the tetraspanin cd81 associated with other tetraspanins, we show that membrane choleste ... | 2006 | 16687736 |
| very little intron loss/gain in plasmodium: intron loss/gain mutation rates and intron number. | we compared intron positions in conserved regions of 3479 orthologous gene pairs from plasmodium falciparum and plasmodium yoelii, which likely diverged >or=100 million years ago (mya). only 27 out of 2212 positions were specific to one of the two species. intron presence in related species shows that at least 19 and possibly 26 of the changes are due to intron loss, depending on phylogeny. the implied intron loss and gain rates are much lower than previously estimated for nematodes, arthropods, ... | 2006 | 16702411 |
| simalikalactone d is responsible for the antimalarial properties of an amazonian traditional remedy made with quassia amara l. (simaroubaceae). | french guiana (north-east amazonia) records high malaria incidence rates. the traditional antimalarial remedy most widespread there is a simple tea made out from quassia amara l. leaves (simaroubaceae). this herbal tea displays an excellent antimalarial activity both in vitro and in vivo. a known quassinoid, simalikalactone d (skd), was identified as the active compound, with an ic(50) value of 10nm against fcb1 plasmodium falciparum chloroquine resistant strain in vitro. lastly, it inhibits 50% ... | 2006 | 16730421 |
| blood schizontocidal activity of selected 1,2,4-trioxanes (fenozans) against the multidrug-resistant strain of plasmodium yoelii nigeriensis (mdr) in vivo. | blood schizontocidal activity of 10 selected cis-fused cyclopenteno-1,2,4-trioxanes (namely fenozan compound nos 6, 7, 11, 27, 32, 39, 44, 45, 48 and 51) have been re-investigated to establish their curative doses against the multidrug-resistant plasmodium yoelii nigeriensis strain, which is lethal in swiss mice. freshly prepared formulations of these compounds prepared either in neutral groundnut (peanut) oil or in dimethyl sulfoxide (dmso)-tween-water, were compared for their antimalarial acti ... | 2006 | 16764736 |
| the phylogeny of rodent malaria parasites: simultaneous analysis across three genomes. | species of plasmodium that naturally infect wild rodents but can also be maintained in laboratory mice have long been used as model systems in which to study the biology of malaria parasites. several of these rodent parasites are now providing useful genomic comparisons to those species that cause malaria in humans. here we examined the phylogenetic relationships of 19 strains of rodent malaria parasites including four species native to african thicket rats (plasmodium berghei, plasmodium chabau ... | 2007 | 16765106 |
| environmental influence on the genetic basis of mosquito resistance to malaria parasites. | the genetic basis of a host's resistance to parasites has important epidemiological and evolutionary consequences. understanding this genetic basis can be complicated by non-genetic factors, such as environmental quality, which may influence the expression of genetic resistance and profoundly alter patterns of disease and the host's response to selection. in particular, understanding the environmental influence on the genetic resistance of mosquitoes to malaria gives valuable knowledge concernin ... | 2006 | 16777744 |
| protein disulfide isomerase assisted protein folding in malaria parasites. | in eukaryotes, the formation of protein disulfide bonds among cysteine residues is mediated by protein disulfide isomerases and occurs in the highly oxidised environment of the endoplasmic reticulum. this process is poorly understood in malaria parasites. in this paper, we report the gene isolation, sequence and phylogenetic comparisons, protein structure and thioredoxin-domain analyses of nine protein disulfide isomerases-like molecules from five species of malaria parasites including plasmodiu ... | 2006 | 16806221 |
| nk cell responses to plasmodium infection and control of intrahepatic parasite development. | various components of innate and adaptive immunity contribute to host defenses against plasmodium infection. we investigated the contribution of nk cells to the immune response to primary infection with plasmodium yoelii sporozoites in c57bl/6 mice. we found that hepatic and splenic nk cells were activated during infection and displayed different phenotypic and functional properties. the number of hepatic nk cells increased whereas the number of splenic nk cells decreased. expression of the ly49 ... | 2006 | 16818782 |
| expression of human cd81 differently affects host cell susceptibility to malaria sporozoites depending on the plasmodium species. | plasmodium sporozoites can enter host cells by two distinct pathways, either through disruption of the plasma membrane followed by parasite transmigration through cells, or by formation of a parasitophorous vacuole (pv) where the parasite further differentiates into a replicative exo-erythrocytic form (eef). we now provide evidence that following invasion without pv formation, transmigrating plasmodium falciparum and plasmodium yoelii sporozoites can partially develop into eefs inside hepatocarc ... | 2006 | 16819966 |
| the plasmodium vivax homolog of the ookinete adhesive micronemal protein, ctrp. | the plasmodium circumsporozoite protein/thrombospondin-related anonymous protein-related protein (ctrp) is expressed at the mosquito midgut ookinete stage and is considered to be a transmission-blocking vaccine candidate. ctrp is composed of multiple von willebrand factor a (vwa) and thrombospondin type 1 domains in the extracellular portion of the molecule, and a short acidic cytoplasmic domain that interacts with the actomyosin machinery. as a means to predict functionally relevant domains wit ... | 2006 | 16822707 |
| expression, localization, and erythrocyte binding activity of plasmodium yoelii merozoite surface protein-8. | pymsp-8 is a member of a family of merozoite surface proteins that have been described in plasmodium that are characterized by the presence of a glycolipid membrane anchor and 1-2 epidermal growth factor-like domains. immunization with recombinant pymsp-8 has also been shown to protect mice against lethal plasmodium yoelii malaria. in this report, we demonstrate that pymsp-8 expression is detectable throughout the entire erythrocytic life cycle of p. yoelii 17xl, reaching peak level during troph ... | 2006 | 16846654 |
| study on protective immunity against infection of plasmodium yoelii 17xl in dba/2 mice. | to investigate the development and dynamic changes of host immune response in dba/2 mice infected with plasmodium yoelii 17xl. | 2006 | 16866134 |
| protection against malaria due to innate immunity enhanced by low-protein diet. | mice were fed ad libitum with a normal diet (25% protein) or low-protein diets (0-12.5% protein) for a wk and then infected with a nonlethal or lethal strain of plasmodium yoelii, that is, blood stage infection. the same diet was continued until recovery. mice fed with a normal diet showed severe parasitemia during nonlethal infection, but survived the infection. they died within 2 wk in the case of lethal infection. however, all mice fed with low-protein diets survived without apparent parasite ... | 2006 | 16883996 |
| quantitative isolation and in vivo imaging of malaria parasite liver stages. | the liver stages of plasmodium, the causative agent of malaria, are the least explored forms in the parasite's life cycle despite their recognition as key vaccine and drug targets. in vivo experimental access to liver stages of human malaria parasites is practically prohibited and therefore rodent model malaria parasites have been used for in vivo studies. however, even in rodent models progress in the analysis of liver stages has been limited, mainly due to their low abundance and associated di ... | 2006 | 16890231 |
| kupffer cells are obligatory for plasmodium yoelii sporozoite infection of the liver. | previous studies suggested plasmodium sporozoites infect hepatocytes after passing through kupffer cells, but proof has been elusive. here we present new information strengthening that hypothesis. we used homozygous op/op mice known to have few kupffer cells because they lack macrophage colony stimulating factor 1 required for macrophage maturation due to a deactivating point mutation in the osteopetrosis gene. we found these mice to have 77% fewer kupffer cells and to exhibit reduced clearance ... | 2007 | 16953803 |
| differences in the copy number of the py235 gene family in virulent and avirulent lines of plasmodium yoelii. | the 235kda rhoptry protein (py235) of plasmodium yoelii is coded for by a multigene family. py235 has been implicated in host cell selection and virulence as antibodies against it have been shown to inhibit invasion of mature red blood cells of the normally virulent p. yoelii ym line and at least one member of this family directly binds to erythrocytes. differences in py235 sequence and copy number have been postulated to be responsible for the differences in invasion phenotype seen in the aviru ... | 2006 | 16959335 |
| large-scale intron conservation and order-of-magnitude variation in intron loss/gain rates in apicomplexan evolution. | the age of modern introns and the evolutionary forces controlling intron loss and gain remain matters of much debate. in the case of the apicomplexan malaria parasite plasmodium falciparum, previous studies have shown that while the positions of two thirds of p. falciparum introns are not shared with surveyed non-apicomplexans (leaving open the possibility that they were relatively recently gained), 99.1% are shared with plasmodium yoelii, which diverged from p. falciparum at least 100 mya. we s ... | 2006 | 16963708 |
| passive immunization with a multicomponent vaccine against conserved domains of apical membrane antigen 1 and 235-kilodalton rhoptry proteins protects mice against plasmodium yoelii blood-stage challenge infection. | during malaria parasite invasion of red blood cells, merozoite proteins bind receptors on the surface of the erythrocyte. two candidate plasmodium yoelii adhesion proteins are apical membrane antigen 1 (ama1) and the 235-kda rhoptry proteins (p235). previously, we have demonstrated that passive immunization with monoclonal antibodies (mabs) 45b1 and 25.77 against ama1 and p235, respectively, protects against a lethal challenge infection with p. yoelii ym. we show that mab 45b1 recognizes an epit ... | 2006 | 16988228 |
| immunological responses of neonates and infants to dna vaccines. | in some parts of sub-saharan africa, it is believed that most of the deaths attributed to malaria occur in infants. for this and other logistical reasons, if a malaria vaccine is developed and licensed, it will have to be administered to neonates or young infants, when they have maternally acquired antibodies against malaria parasite proteins. pre-erythrocytic malaria vaccines in development rely on cd8(+) t cells as immune effectors, yet some studies indicate that neonates do not mount optimal ... | 2006 | 16988458 |
| co-infection by semliki forest virus and malarial parasite modulates viral multipucation, pathogenesis and cytokines in mice. | environmental, technological and societal factors continue to have a dramatic effect on infectious diseases worldwide and are considered to be facilitating the emergence of several infectious diseases at a time. co-infection with different species of viral and malaria infections are currently emerging problems of dual infection in the developing as well as developed countries. understanding of interactions between the host, malaria and virus infection is of current concern and we have initiated ... | 2006 | 17007218 |
| purification and biochemical characterization of cytosolic glutathione-s-transferase from malarial parasites plasmodium yoelii. | glutathione (gsh) metabolism represents a potential target for antiparasitic drug design. glutathione-s-transferase (gst), an important enzyme of the gsh cycle, is considered to be an essential detoxification enzyme in parasitic species. soluble gst from rodent malarial parasites plasmodium yoelii was purified to homogeneity using a combination of salt precipitation, affinity chromatography on gsh-sepharose 6b and ultrafiltration. sodium dodecyl sulfate polyacrylamide gel electrophoresis (sds-pa ... | 2007 | 17024358 |
| plasmodium yoelii yoelii 17xnl constitutively expressing gfp throughout the life cycle. | plasmodium yoelii is a rodent parasite commonly used as a model to study malaria infection. it is the preferred model parasite for liver-stage immunological studies and is also widely used to study hepatocyte, erythrocyte and mosquito infection. we have generated a p. yoelii yoelii 17xnl line that is stably transfected with the green fluorescent protein (gfp) gene. this parasite line constitutively expresses high levels of gfp during the complete parasite life cycle including liver, blood and mo ... | 2007 | 17049517 |
| aav vectors encoding malarial antigens stimulate antigen-specific immunity but do not protect from parasite infection. | this study explores the utility of recombinant adeno-associated virus (raav) as a genetic vaccine delivery system using muscle as a target tissue. a single injection of raav encoding the malarial antigens msp4 (plasmodium falciparum) or msp4/5 (plasmodium yoelii) stimulated long-term antigen-specific antibody responses. anti-msp4/5 immunity stimulated by aav was not protective against p. yoelii infection and efforts taken to augment antibody responses against msp4/5, either by priming with plasm ... | 2007 | 17081661 |
| plasmodium yoelii: the effect of second blood meal and anti-sporozoite antibodies on development and gene expression in the mosquito vector, anopheles stephensi. | the sporogonic development of the malaria parasite takes place in the mosquito and a wide range of factors modulates it. among those, the contents of the blood meal can influence the parasite development directly or indirectly through the mosquito response to the infection. we have studied the effect of a second blood meal in previously infected mosquitoes and the effect of anti-sporozoite immune serum on parasite development and mosquito response to the infection. the prevalence and intensity o ... | 2007 | 17083935 |
| plasmodium yoelii: distinct cd4(+)cd25(+) regulatory t cell responses during the early stages of infection in susceptible and resistant mice. | the outcome of experimental murine infection with different strains of malaria parasites, ranging from spontaneous cure to death, depends largely on the establishment of effective th1 responses during the early stages of infection. here we describe the disparity in cd4(+)cd25(+) regulatory t cell (treg) responses during the early stages of infection with the highly virulent plasmodium yoelii 17xl strain in susceptible (balb/c) and resistant (dba/2) mice. an increased proportion of tregs 3-4 days ... | 2007 | 17084842 |
| exacerbation of plasmodium yoelii malaria in echinostoma caproni infected mice and abatement through anthelmintic treatment. | the effect of chronic intestinal trematode infection on malaria was examined in a murine model of co-infection using echinostoma caproni and plasmodium yoelii. balb/c mice (n = 32) infected with a low dose of e. caproni (approximately 10 cysts) 25-35 days before malaria infection displayed significantly increased malaria parasitemia (p = 0.01), extended patency of malaria (p = 0.03), and increased fatality (47%; p < 0.001) compared to mice infected only with p. yoelii (17x nonlethal strain) (n = ... | 2005 | 17089770 |
| alternative invasion pathways for plasmodium berghei sporozoites. | invasion of hepatocytes by plasmodium sporozoites is a prerequisite for establishment of a natural malaria infection. the molecular mechanisms underlying sporozoite invasion are largely unknown. we have previously reported that infection by plasmodium falciparum and plasmodium yoelii sporozoites depends on cd81 and cholesterol-dependent tetraspanin-enriched microdomains (tems) on the hepatocyte surface. here we have analyzed the role of cd81 and tems during infection by sporozoites from the rode ... | 2007 | 17112526 |
| new orally active derivatives of artemisinin with high efficacy against multidrug-resistant malaria in mice. | a new series of ether derivatives of dihydroartemisinin have been prepared and evaluated for their antimalarial activity against multidrug-resistant plasmodium yoelii nigeriensis in mice by oral route. these new derivatives 7-17 are highly lipophilic (log p in the range of 5.51 to 7.19) as compared with beta-arteether (log p 3.84), and several of them are two- to four-fold more active than beta-arteether. among the ether derivatives, alpha-isomers are more active than the beta-isomers. the ether ... | 2006 | 17125275 |
| inhibition of plasmodium falciparum choline kinase by hexadecyltrimethylammonium bromide: a possible antimalarial mechanism. | choline kinase is the first enzyme in the kennedy pathway (cdp-choline pathway) for the biosynthesis of the most essential phospholipid, phosphatidylcholine, in plasmodium falciparum. in addition, choline kinase also plays a pivotal role in trapping essential polar head group choline inside the malaria parasite. recently, plasmodium falciparum choline kinase (pfck) has been cloned, overexpressed, and purified. however, the function of this enzyme in parasite growth and survival has not been eval ... | 2007 | 17145794 |
| comparasite: a database for comparative study of transcriptomes of parasites defined by full-length cdnas. | comparasite is a database for comparative studies of transcriptomes of parasites. in this database, each data is defined by the full-length cdnas from various apicomplexan parasites. it integrates seven individual databases, full-parasites, consisting of numerous full-length cdna clones that we have produced and sequenced: 12,484 cdna sequences from plasmodium falciparum, 11,262 from plasmodium yoelii, 9633 from plasmodium vivax, 1518 from plasmodium berghei, 7400 from toxoplasma gondii, 5921 fr ... | 2007 | 17151081 |
| enhanced protection against malaria by a chimeric merozoite surface protein vaccine. | the 42-kda processed fragment of plasmodium falciparum merozoite surface protein 1 (msp-1(42)) is a prime candidate for a blood-stage malaria vaccine. merozoite surface protein 8 contains two c-terminal epidermal growth factor (egf)-like domains that may function similarly to those of msp-1(42). immunization with either msp-1 or msp-8 induces protection that is mediated primarily by antibodies against conformation-dependent epitopes. in a series of comparative immunogenicity and efficacy studies ... | 2007 | 17158895 |