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pneumocystis carinii: sequence from ribosomal rna implies a close relationship with fungi.pneumocystis carinii is the etiologic agent of a lethal pneumonia which occurs in patients with the acquired immune deficiency syndrome (aids) and other immunocompromised hosts. the basic biochemical and genetic characteristics of p. carinii are poorly understood and its taxonomic classification as a protozoan is uncertain. to address the taxonomic question, a method was developed for the extraction of total rna from p. carinii. denaturing agarose gel electrophoresis showed the two ribosomal rna ...19892470612
[use a of dna probe to detect cellular immunity against intracellular parasitism].by using a specific, repetitive dna probe, we have been able to detect picograms of p. berghei dna. with this probe we have determined that: a) p. berghei, inoculated into norway brown rats, reaches its peak of proliferation in the liver 44 h after infection; b) gamma interferon inhibits in a dose-dependent fashion the development of liver exoerythrocytic forms (eef) in vivo and in vitro, and; c) endogenous gamma interferon inhibits the development of eef in hosts immunized with irradiated sporo ...19901723869
sfii and noti polymorphisms in theileria stocks detected by pulsed field gel electrophoresis.dnas of theileria parva parva, t. p. lawrencei, t. p. bovis and theileria mutans stocks, from kenya, uganda, zanzibar and zimbabwe were digested with either sfii or noti and analysed using contour-clamped homogeneous electric field (chef) and field-inversion gel electrophoresis (fige). the sfii-digested t. parva genomic dna resolved into approximately 30 fragments while the noti digestion produced between 4-7 bands. the summation of the sizes of sfii fragments gave an estimate of 9-10 x 10(6) ba ...19901972977
generation of chromosome size polymorphism during in vivo mitotic multiplication of plasmodium berghei involves both loss and addition of subtelomeric repeat sequences.extensive chromosome size polymorphism arises in plasmodium berghei during in vivo mitotic multiplication. size differences between homologous chromosomes involve rearrangements occurring in the subtelomeric portions while internal chromosomal regions do not contribute significantly to chromosome size polymorphism. differences in the copy number of a 2.3-kb subtelomeric repeated unit are shown to correlate with size variations, and in at least one case to account completely for the size differen ...19901974695
survival and antigenic profile of irradiated malarial sporozoites in infected liver cells.exoerythrocytic (ee) stages of plasmodium berghei derived from irradiated sporozoites were cultured in vitro in hepg2 cells. they synthesized several antigens, predominantly but not exclusively those expressed by normal early erythrocytic schizonts. after invasion, over half the intracellular sporozoites, both normal and irradiated, appeared to die. after 24 h, in marked contrast to the normal parasites, ee parasites derived from irradiated sporozoites continued to break open, shedding their ant ...19901974886
pyrimidine biosynthesis in parasitic protozoa: purification of a monofunctional dihydroorotase from plasmodium berghei and crithidia fasciculata.dihydroorotase (dhoase) catalyzes the reversible cyclization of n-carbamoyl-l-aspartate (l-ca) to l-5,6-dihydroorotate (l-dho), which is the third enzyme in de novo pyrimidine biosynthesis. the enzyme was purified from two parasitic protozoa, crithidia fasciculata (about 16,000-fold) and plasmodium berghei (about 790-fold). the c. fasciculata enzyme had a native molecular weight (mr) of 42,000 +/- 5000, determined by gel filtration chromatography, and showed a single detectable protein band on s ...19901976382
the effect of malaria infection on the disposition of quinine and quinidine in the rat isolated perfused liver preparation.the effect of malaria on the disposition of quinine and quinidine was studied in livers isolated from young rats infected with merozoites of plasmodium berghei, a rodent malaria model, and non-infected controls. following bolus administration of quinine (1 mg) or quinidine (1 mg) to the 100 ml recycling perfusion circuit, perfusate was sampled (0-4 h) and plasma assayed for quinine and quinidine by hplc. higher quinine (auc:6470 +/- 1101 vs 3822 +/- 347 ng h ml-1, p less than 0.001) and quinidin ...19901979624
the chemotherapy of rodent malaria. xlv. reversal of chloroquine resistance in rodent and human plasmodium by antihistaminic agents.the inherent blood schizontocidal activities of five antihistaminic compounds, cyproheptadine hydrochloride (cyp), ketotifen hydrogen fumarate (ket), pizotyline hydrogen maleate (piz), azatadine maleate (azat) and loratadine (lor) were examined against the following organisms: chloroquine-sensitive (cs) plasmodium berghei and chloroquine-resistant (cr) p. yoelii ssp. ns in mice; and cs tak 9 clone 96 and cr k1 strain of p. falciparum in vitro. chloroquine, verapamil and desipramine were used as ...19901981663
the circumsporozoite protein of plasmodium: a mechanism of immune evasion by the malaria parasite?sporozoites of malaria are covered with a repetitive surface antigen, the circumsporozoite (cs) protein. this antigen also appears to be a major target of the host immune response. the natural immunogenicity of the cs protein has led to attempts to develop the molecule as a vaccine candidate. it seems paradoxical, however, that a successful parasite should present to the host an immunogenic surface molecule which would induce protective immunity. in this paper we suggest that the cs protein is n ...19901709835
incorporation of t and b epitopes of the circumsporozoite protein in a chemically defined synthetic vaccine against malaria.we show here an effective and novel approach to engineer peptide-based vaccines using a chemically defined system, known as multiple peptide antigen systems (maps), to protect an inbred mouse strain from infection against rodent malaria. 10 mono- and di-epitope map models containing different arrangements and stoichiometry of functional b and/or t helper cell epitopes from the circumsporozoite protein of plasmodium berghei were used to immunize a/j mice. while these mice did not respond to the m ...19901688609
plasmodium berghei subunit vaccine: repeat synthetic peptide of circumsporozoite protein comprising t- and b-cell epitopes fails to confer immunity.in the murine malaria model induced by plasmodium berghei, we studied the immunogenicity of the repeat region of the circumsporozoite (cs) protein, which is the main target of the antibody response in infected animals. we immunized several strains with a synthetic peptide--y(dppppnpn)3--corresponding to one of the two p. berghei repeat sequences in complete freund's adjuvant. only c57bl/6 immune sera reacted with the synthetic peptide in elisa and with the native cs protein on p. berghei sporozo ...19901689867
immune responses to defined epitopes of the circumsporozoite protein of the murine malaria parasite, plasmodium yoelii.we have investigated the immunogenicity of defined sequences of the circumsporozoite (cs) protein of the murine malaria parasite, plasmodium yoelii. a 21-ner synthetic peptide from the nonrepetitive region of the cs protein (position 59-79, referred to as py1) induced t cell proliferative responses in h-2d and, to a lesser extent, in h-2b mice. conversely, a synthetic peptide (referred to as py4) consisting of four (qgpgap) repeats of the p. yoelii cs protein, induced an antibody response only i ...19901695152
three non-repeated transmission blocking epitopes recognized in the 21 kd surface antigen of zygotes-ookinetes of plasmodium berghei.two-site and competitive elisa have been developed against a surface antigen of zygotes-ookinetes of plasmodium berghei using monoclonal antibodies (moabs) which block transmission of the parasite to the mosquito. three such moabs have been studied, each of which recognized a protein of an mr 21 kd (pbs21) using immunoblot techniques. the assays showed that there are at least 3 single b-cell epitopes expressed in pbs21. one epitope recognized by moab 17.9 is conformation dependent and antibodies ...19901698275
oral salmonella: malaria circumsporozoite recombinants induce specific cd8+ cytotoxic t cells.oral immunization with an attenuated salmonella typhimurium recombinant containing the full-length plasmodium berghei circumsporozoite (cs) gene induces protective immunity against p. berghei sporozoite challenge in the absence of antibody. we found that this immunity was mediated through the induction of specific cd8+ t cells since in vivo elimination of cd8+ cells abrogated protection. in vitro studies revealed that this salmonella-p. berghei cs recombinant induced class i-restricted cd8+ cyto ...19901698908
isolation and characterization of protective cytolytic t cells in a rodent malaria model system.protective immunity against malaria is induced by immunization with irradiation-attenuated sporozoites. here we report the isolation of cytolytic t-cell (ctl) clones from balb/c (h-2d) mice immunized with either plasmodium berghei or plasmodium yoelii sporozoites. the epitopes recognized by these ctl can be mimicked by synthetic peptides corresponding to a homologous region in the cs proteins of both rodent malaria species. both peptides are recognized by the ctl in the context of the same mhc c ...19901704348
protective anti-sporozoite antibodies induced by a chemically defined synthetic vaccine.chemically defined synthetic polymers, known as multiple antigen peptide systems (maps) represent an effective and novel approach for engineering peptide-based vaccines. ten different mono and diepitope map models, containing different arrangements and stoichiometry of functional b and/or t helper epitopes from the circumsporozoite protein of plasmodium berghei were used to immunize mice. high titers of antibody and protective immunity against sporozoite challenge were elicited by maps containin ...19901704349
peptide-primed cd4+ cells and malaria sporozoites.we have mapped a t cell epitope in the circumsporozoite (cs) protein of the murine malaria parasite, plasmodium yoelii. a 21-mer synthetic peptide corresponding to the amino acid positions 59-79 (referred to as py1), induced specific proliferation in balb/c and c57bl/6 mice, and provided help for the production of antibodies to peptides from the repetitive region, (qgpgap)n, of the same cs protein, when mice were immunized with the py1 peptide conjugated to the repetitive peptide. long-term cd3+ ...19901704350
evaluation of the antimalarial activity of new compounds against plasmodium falciparum in vitro, and plasmodium berghei in vivo.various hydrazones of thiophene carboxaldehyde were tested in vitro on two plasmodium falciparum strains and in vivo on mice experimentally infected with plasmodium berghei. these hydrazones were obtained by condensation of appropriate hydrazines with thiophene-2-carboxaldehyde (series 1), thiophene-3- carboxaldehyde (series 2) and 5-nitrothiophene-2-carboxaldehyde (series 3). compounds of series 3, 5-nitrothiophene-2-carboxaldehyde presented significant effects in vitro. in vivo tests confirmed ...19902086754
a cytochemical ultrastructural study of the lysosomal system of different species of malaria parasites.we have used ultrastructural techniques in different malarial species to demonstrate a lysosomal system. first, we have tried to localize acid phosphatase, a typical lysosomal label. its activity was localized in the endoplasmic reticulum and in endocytic vesicles, and in dense-cored vesicles near the digestive vacuoles, especially in plasmodium falciparum (fcr3 strain). then, we have studied the different cellular compartments of the malarial parasite by the zinc iodide-osmium tetroxide techniq ...19902086778
plasmodium sporozoite interactions with macrophages in vitro: a videomicroscopic analysis.studies of in vitro interactions between plasmodium berghei sporozoites and peritoneal macrophages from mice and rats were performed. a videomicroscopic analysis was made of interactions observed by phase-contrast microscopy. our results showed a diversity of dynamic interactions between sporozoites and macrophages that included no interaction, surface interaction without sporozoite interiorization, active sporozoite penetration, active penetration with subsequent sporozoite escape, macrophage d ...19902086782
the development and routine application of high-density exoerythrocytic-stage cultures of plasmodium berghei.methods are reviewed for the culture of the exoerythrocytic stages of plasmodium berghei wherein development reproducibly reflects growth observed in vivo in laboratory rodents. the combination of these methods with the culture of both asexual and sexual blood stages has allowed the completion of the entire vertebrate phase of malaria development in vitro. the development of new methods for high-density exoerythrocytic-stage culture combined with robust statistical analysis of parasite growth by ...19902094577
delayed-type hypersensitivity and protection in mice following immunization with plasmodium berghei sporozoites.the measurement of footpad swelling (fps) following the inoculation of sporozoite antigen (ag) into the hind footpad (hfp) of outbred mice was used as an in vivo test of delayed-type hypersensitivity (dth) to attenuated sporozoite immunization. an attempt was made to correlate dth with protective antisporozoite immunity. the optimum time for testing dth following a single intravenous immunization was four days. the optimum sensitizing dose was 1 x 10(5) attenuated sporozoites. a single immunizat ...19902094579
a liver-stage specific antigen of p. berghei identified by a monoclonal antibody.stage-specific immunity (to the sporozoite, the asexual blood-stages and the sexual stages of malaria) has been well documented and antigens from each stage are being tested for their potential as vaccine candidates. recently it has become clear that the liver stage can also be the target of protective immune responses; however, only the circumsporozoite protein has been identified as a protective liver antigen. it is critical for vaccine evaluation and development to identify other liver antige ...19902094583
pre-erythrocytic stage malaria parasites: non-circumsporozoite protein antigens.a series of non-circumsporozoite proteins found in pre-erythrocytic parasites are being developed as putative vaccine candidates. it is anticipated that these will be useful in addition to, rather than instead of, the cs (circumsporozoite) vaccines. it is likely that a greater understanding of the basic biology of malaria parasite-host relationships will lead to development of improved malarial vaccines.19902094584
plasmodium sporozoite-host cell interactions during sporozoite invasion.in vitro and in vivo studies were performed to clarify the nature of some interactions between plasmodium berghei sporozoites and rodent host cells. videomicroscopic observations were made on in vitro interactions between sporozoites and cultured host cells (rodent peritoneal macrophages, w138 human lung fibroblasts, and hepg2 human hepatoma cells). the results showed a diversity of dynamic interactions and sporozoite activities, including active sporozoite penetration, often followed by sporozo ...19902094594
role of circumsporozoite protein-specific t-cells in protective immunity against plasmodium berghei.the plasmodium berghei circumsporozoite (cs) protein-specific t-cell repertoire was analysed in c57bl/6 (h-2b), balb/c (h-2d), and c3h/hen (h-2k) mice immunized with irradiated sporozoites and the proliferative responses were correlated with the protective status of each strain. splenic lymphocytes responded to the priming antigen, but the responses varied according to both murine strain and immunization schedule. analysis of cytolytic t lymphocyte (ctl) responses in mice immunized with irradiat ...19902094596
c-reactive protein and the liver stage of plasmodium vivax and p. berghei. 19902096504
three-dimensional reconstruction of the feeding process of the malaria parasite.the use of serial sectioning followed by three-dimensional (3d) reconstruction is a convenient way to study the spatial morphology of any structure (organ, cell, organelle). this method was applied to the study of the feeding mechanism of some strains of murine and human plasmodium and enabled clarification of morphological features of this process. the feeding and digestive system of plasmodium is polymorphic: in single sections, it shows rounded or elongated vesicles or vacuoles of very differ ...19902096983
use of adjuvants in modulating the behaviour of plasmodium berghei.different adjuvants were assessed for their role in conferring protection against the rodent malarial parasite p. berghei and compared with the classical freund's complete adjuvant (fca). pretreatment of mice with trehalose dimycolate (tdm) mixed with antigen (ag), sulpholipids (sl) mixed with ag, muramyl dipeptide (mdp) alone, liposomes containing ag and phosphomannoinositides (pim) mixed with ag were ineffective in conferring protection. however, mdp given with squalane (sq) and ag, mdp with i ...19902099325
spectrophotometric assay of the interaction between malaria erythrocyte lysates with methylene blue and neutral red dyes.changes of oxidative processes induced in mouse erythrocytes by plasmodium berghei were studied in the presence of methylene blue, neutral red or of both cationic redox dyes. the results are discussed in terms of redox and metachromatic modifications of the dyes which are produced by malarial and normal erythrocyte lysates.19902101204
implications of cytokines in immunopathology: experimental and clinical data. 19902104242
[synthesis of 2-formyl (acetyl) substituted quinoline thiosemicarbazones].a series of 2-formyl (acetyl) substituted quinoline thiosemicarbazones (iii, xii, xiii) were prepared in order to evaluate their antimalarial activity. oxidation of substituted quinolines (iv) with selenium dioxide gave 2-formyl substituted quinolines (v). 2-acetyl substituted quinoline (ix) was obtained from iv by oxidation, esterification, claisen condensation and decarboxylation. iii1-9 were synthesized by two methods; one was by condensation of 2-formyl (acetyl) substituted quinolines with m ...19902104472
interleukin 6 production in experimental cerebral malaria: modulation by anticytokine antibodies and possible role in hypergammaglobulinemia.the production of interleukin 6 (il-6) was studied during experimental cerebral malaria (ecm) induced by plasmodium berghei anka (pba) infection. il-6 is present in the serum of mice with ecm, the highest concentrations being observed in mice with full-blown neurological syndrome. high il-6 levels were also observed, however, in the absence of pathology in nonlethal malaria infection. these data suggest that il-6 is produced in large amounts during malaria infection, but does not play a major ro ...19902121890
immune response to plasmodium berghei sporozoite antigens. i. evaluation of murine t cell repertoire following immunization with irradiated sporozoites.the plasmodium berghei sporozoite antigen-specific t cell repertoire was analyzed in c57bl/6 (h-2b), balb/c (h-2d) and c3h/hen (h-2k) mice following immunization with irradiated sporozoites. proliferative responses were correlated with the protective status of each strain. proliferative reactivities to sporozoite antigens were compared in cultures containing either cd4+ t cells, cd8+ t cells, or total splenic lymphocytes. cd8+ t cells had no proliferative activity to sporozoite antigens; cd4+ t ...19902122748
cellular mechanisms of nonspecific immunity to intracellular infection: cytokine-induced synthesis of toxic nitrogen oxides from l-arginine by macrophages and hepatocytes.nitric oxide (no) produced by cytokine-treated macrophages and hepatocytes plays a vital role in protective host responses to infectious pathogens. no inhibits iron-sulfur-dependent enzymes involved in cellular respiration, energy production, and reproduction. synthesis of l-arginine-derived nitrite (no2-), the oxidative end product of no, directly correlates with intracellular killing of leishmania major, an obligate intracellular protozoan parasite of macrophages: the level of no2- production ...19902126524
effect of anti-mosquito antibodies on the infectivity of the rodent malaria parasite plasmodium berghei to anopheles farauti.the effect of mouse anti-mosquito antibodies, present in the bloodmeal, on the infectivity of plasmodium berghei vincke to anopheles farauti laveran was investigated. significantly fewer oocysts developed in mosquitoes feeding on mice immunized with sugar-fed mosquito midgut antigens than in mosquitoes feeding on control mice. mosquitoes feeding on mice immunized with the midgut antigens derived from sugar-fed mosquitoes also showed reduced mortality and had lower infection rates than those fed ...19902132980
[the possible therapeutic effect of deferoxamine in experimental infections of mice by plasmodium berghei].deferoxamine is a compound with iron chelating properties. body depletion of this mineral, according to some authors, might influence the metabolism of plasmodia that thrive in the erythrocytes. in order to verify this possibility, we administered daily doses of 300 or 1.000 mg/kg of the compound, for five days and again 15 days, to mice infected with plasmodium berghei. the parameters used to check the activity of deferoxamine were mortality of the animals and the count of blood parasites. the ...19902135836
phosphofructokinase from plasmodium berghei. influence of mg2+, atp and mg2(+)-complexed atp.the control enzyme phosphofructokinase is of regulatory significance in the metabolism of glucose by the malarial parasite plasmodium berghei. (1) the enzyme was partially purified from erythrocytic stages of p. berghei by precipitation with poly(ethylene glycol) and chromatography on 2',5'-bisphosphoadenosine-sepharose 4b. (2) similarly to various other phosphofructokinases, the enzyme from p. berghei shows an allosteric behaviour. it is activated by fructose 6-phosphate and inhibited by atp. ( ...19902139776
immunosuppression in murine malaria: suppressor role of macrophages and their products during acute and chronic plasmodium berghei infection.marked suppression of igm, igg and iga plaque forming cells was observed in mice immunized with sheep erythocytes (t-dependent antigen) during acute plasmodium berghei infection whereas during chronic infection mild immunosuppression was observed. when mice were immunized with polyvinylpyrrolidone (t-independent antigen), suppression in the number of plaque forming cells was observed at higher parasitaemias only during acute infection whereas during chronic infection the number remained within n ...19902141476
phosphofructokinase from plasmodium berghei: a kinetic model of allosteric regulation.as in mammalian cells, phosphofructokinase (pfk) is of major regulatory importance in the glucose metabolism of plasmodium berghei. the malarial enzyme shows allosteric properties similar to pfk from various sources; it is activated by fructose-6-phosphate and inhibited by atp, but differs with respect to allosteric regulation. enzyme activity is only marginally increased by amp, a potent activator of many phosphofructokinases. phosphoenolpyruvate, which is reported to inhibit pfk activity, effi ...19902141917
regulation of the energy metabolism of plasmodium berghei.energy metabolism of malaria parasites was investigated in p. berghei infected red blood cells of rat. although plasmodia contain mitochondria most of their atp is formed by glycolysis. lactate formation is two orders of magnitude higher than in noninfected erythrocytes. the coupling of respiration and glycolysis is very loose, a pasteur-effect was not found. the key enzymes of glycolysis hexokinase and phosphofructokinase have been partially purified and kinetically characterized. the kinetic p ...19902143651
mitogenic activity of soluble preparations from plasmodium berghei-infected erythrocytes to l3t4+, lyt2- and l3t4-, lyt2+ t-cell subsets.the mitogenic activity of soluble preparations of plasmodium berghei-infected erythrocytes (pbep) in cultures of t or non-t cells isolated from spleens of naive mice was investigated. the proportion of cells at each phase in the cell cycle was examined by flow cytometry after incubation with various concentrations of pbep; the proliferation index (pi-cell numbers at s, g2 and m phases/cell numbers at all phases x 100) was calculated. an addition of pbep led to significant increases in the pi lev ...19902144965
changes in hemopoietic and regulator levels in mice during fatal or nonfatal malarial infections. i. erythropoietic populations.erythroid precursors bfu-e and cfu-e and erythroblasts (erb) were monitored in the marrow and spleen of mice during fatal or nonfatal malaria. transient depletions of marrow cfu-e and erb without modification of bfu-e or erythropoietin (epo) levels were found as early events in fatal infections. before anemia development, erythropoiesis was reduced in the bone marrow but increased in the spleen. during the anemic phase, for comparable levels of anemia, plasma epo levels were elevated to a simila ...19902146141
quantitative estimation of suppressor/cytotoxic and helper t cells during acute and chronic plasmodium berghei infection.in the present study, the percentage of lymphocyte subpopulations and their relation to t cell subsets was estimated during acute and chronic plasmodium berghei malaria. during acute infection, a decreased percentage of t lymphocytes was observed, whereas no change was observed during chronic infection. however, no change in the percentage of b cells was observed in both types of infection. the t cell population was characterized by an increased percentage of t suppressor cytotoxic (cd8+) cells ...19902146216
cd4+ cytolytic t cell clone confers protection against murine malaria.a cd4+ t cell clone (a1.6) was derived from spleen cells of mice immunized with irradiated sporozoites. this t cell clone recognizes an antigen that is shared by sporozoites and blood forms of plasmodium berghei and differs from the circumsporozoite protein. clone a1.6 displays cytotoxic activity, produces ifn-gamma and il-2 in vitro, and recognizes the plasmodial antigen in the context of the class ii i-ed molecule. passive transfer of this cd4+ clone into naive mice resulted in a high degree o ...19902146361
t lymphocytes from mice immunized with irradiated sporozoites eliminate malaria from hepatocytes.when mice are immunized with radiation-attenuated sporozoites they are solidly protected against sporozoite challenge by an immune response that has been shown to require cd8+ lymphocytes in several strains of mice. the target of this cd8+ t-cell-dependent immunity has not been established. immune balb/c mice were shown to develop malaria-specific, cd8+ t-cell-dependent inflammatory infiltrates in their livers after challenge with plasmodium berghei sporozoites. spleen cells from immune balb/c a ...19902151270
in vitro effects of primaquine and primaquine metabolites on exoerythrocytic stages of plasmodium berghei.the antimalarial activities of primaquine and its metabolites against exoerythrocytic (ee) stages of plasmodium berghei in vitro were compared with their abilities to spontaneously generate activated oxygen. a quantitative relationship between the number of sporozoites and the number of ee merozoites produced was established. the reduction in the number of merozoites was used as an assay of drug activity. the ed50 of primaquine, 3.7-3.9 x 10(-6) m, was the concentration of drug that reduced the ...19902164790
endopeptidase activities of streptococcus cremoris. 19902165941
possible roles of ca2+ and cgmp as mediators of the exflagellation of plasmodium berghei and plasmodium falciparum.the roles of ca2+ and cyclic nucleotides as secondary, intracellular messengers for exflagellation of plasmodium berghei and plasmodium falciparum were investigated. treatment with ca2+ antagonists such as tmb-8 (an inhibitor of intracellular ca2+ release) or w-7 (a calmodulin inhibitor) strongly inhibited exflagellation induced by alkaline medium at ph 8.0 whereas egta (a ca2+ chelator) or nicardipine and nifedipine (ca2+ channel inhibitors) had no effect. these results may indicate that mobili ...19902172816
long insertions within telomeres contribute to chromosome size polymorphism in plasmodium berghei.during prolonged in vivo mitotic multiplication of a plasmodium berghei anka clone (8417hp), parasites that contained an enlarged version of chromosome 4 were observed. restriction mapping and hybridization results demonstrated that the extra dna present in the enlarged chromosome consists of 2.3-kb tandem repeats, known to be normally located in subtelomeric position at several chromosomal ends but absent in the original chromosome. the inserted 2.3-kb units appeared to interrupt one of the ori ...19902174115
glucose-6-phosphate dehydrogenase from plasmodium berghei: kinetic and electrophoretic characterization.evidence is given for the existence of a parasite-specific glucose-6-phosphate dehydrogenase (g6pd) in plasmodium berghei by characterization of its kinetic and electrophoretic properties. from infected rat erythrocytes the parasites were isolated, washed, and lysed. g6pd was purified by affinity chromatography with 2'5'-adp-sepharose 4b, although the separation of the malaria-specific enzyme from that of the host cell was not complete. malarial g6pd significantly differed from the red cell enzy ...19902178950
sporontocidal activity of the antimalarial wr-238605 against plasmodium berghei anka in anopheles stephensi.the influence of wr-238605 (8-[(4-amino-1-methyl-butyl) amino]-2,6-dimethoxy-4-methyl-5-[3-tri-fluoromethylphenoxyl] quinoline succinate) on the sporogonic development of a plasmodium berghei anka clone was determined. anopheles stephensi were fed on p. berghei infected mice treated 90 min earlier with 25 or 50 mg wr-238605/kg body weight. mosquitoes engorging on drug-treated mice produced the same number of ookinetes as did those fed on controls; drug-fed mosquitoes produced fewer oocysts/mosqu ...19902180334
association of plasmodium berghei proteins with the host erythrocyte membrane: binding to inside-out vesicles.two acidic phosphoproteins of plasmodium berghei origin, of 65 and 46 kda, are associated with the plasma membrane of the host mouse erythrocyte. the 65-kda protein partitions between a soluble and particulate phase upon host cell lysis, whereas the 46-kda protein is localized exclusively in the particulate fraction. both proteins bind to inside-out vesicles derived from erythrocyte ghosts and the conditions of the reassociation reaction indicate that the binding is specific and that the protein ...19902181301
the effect of bacillus sphaericus upon the susceptibility of anopheles quadrimaculatus to plasmodium berghei.larvae of anopheles quadrimaculatus were exposed to bacillus sphaericus. the surviving adults took blood meals on hamsters infected with plasmodium berghei. fewer mosquitoes were infected than were the paired controls. the inhibitory action appeared to occur during the early stages of the infection in the mosquito gut.19902182774
organization of subtelomeric repeats in plasmodium berghei.several (but not all) plasmodium berghei chromosomes bear in the subtelomeric position a cluster of 2.3-kilobase (kb) tandem repeats. the 2.3-kb unit contains 160 base pairs of telomeric sequence. the resulting subtelomeric structure is one in which stretches of telomeric sequences are periodically spaced by a 2.1-kb reiterated sequence. this periodic organization of internal telomeric sequences might be related to chromosome-size polymorphisms involving the loss or addition of subtelomeric 2.3- ...19902183034
purification and characterization of 37-kilodalton proteases from plasmodium falciparum and plasmodium berghei which cleave erythrocyte cytoskeletal components.cytosoluble 100,000 x g extracts from plasmodium berghei or plasmodium falciparum infected red blood cells were shown to hydrolyze erythrocyte spectrin. by fast protein liquid chromatography (fplc), these enzymes were purified and exhibited a pi of 4.5 and mr of 37,000 using sds-page under reducing conditions. an immunochemical enzyme assay using anti-spectrin antibodies was developed. the optimal activity using spectrin as substrate was at ph 5.0, and the enzymes were strongly inhibited by hgcl ...19902183048
nucleotide sequence of the plasmodium berghei circumsporozoite protein gene from the anka clone 2.34l. 19902183186
differences in susceptibility among mouse strains to infection with plasmodium berghei (anka clone) sporozoites and its relationship to protection by gamma-irradiated sporozoites.three inbred mouse strains, c57bl/6 (h-2b), a/j (h-2a), and balb/c (h-2d), and 1 outbred strain, cd-1, demonstrated differences in susceptibility to iv challenge with the anka clone of plasmodium berghei. mice were challenged with 100, 1,000, or 10,000 sporozoites, then evaluated daily beginning on day 4 for patency. cd-1 mice were further evaluated at challenge doses of 12,500, 25,000, and 50,000 sporozoites. c57bl/6 mice were the easiest to infect, with 90% becoming infected with 100 sporozoit ...19902184689
[new antimalarial sustained-release formulations based on bioresorbable polymers: therapeutic evaluation using the plasmodium berghei model].chemotherapy keeps an important place in malaria control programme. the development of schizonticidal formulations, which may maintain their efficacy for at least one month after single administration, becomes needful. these formulations should allow to assure a suitable patient compliance and to avoid the disadvantages of high plasmatic peaks. the aim of this study is to evaluate the therapeutic efficacy of implantable bioresorbable reservoir-forms. the use of these polymers allow to avoid the ...19902185357
evaluation of hepatoprotective activity of picroliv (from picrorhiza kurroa) in mastomys natalensis infected with plasmodium berghei.administration of picroliv, a standardized fraction of alcoholic extent of picrorhiza kurroa (3-12 mg/kg/day for two weeks) simultaneously with p. berghei infection showed significant protection against hepatic damage in mastomys natalensis. the increased levels of serum glutamate oxaloacetate transaminase (got), glutamate pyruvate transaminase (gpt), alkaline phosphatase, lipoprotein-x (lp-x) and bilirubin in the infected animals were marked reduced by different doses of picroliv. in the liver, ...19902189829
detection of dna sequences in plasmodium berghei by means of in situ hybridization.a non-radioactive in situ hybridization technique, used to map unique dna sequences to plant chromosomes, has been adapted for the localization of specific dna sequences in nuclei of plasmodium berghei. after hybridization using probes labeled with biotin-11-dutp, the formed dna/dna hybrids were detected by fluorescence microscopy using a specific double-layer antibody technique. besides its high resolution, this procedure is characterized by a high sensitivity, allowing the detection of a uniqu ...19902190950
reactive oxygen species generation by kupffer cells and blood monocytes of mice infected with plasmodium berghei and the chloroquine treatment.generation of reactive oxygen species (ros) by blood monocytes and kupffer cells of normal and plasmodium berghei infected mice treated at different levels of parasitaemia with chloroquine, were studied. cells isolated at lower level of parasitaemia (less than 2%) produced ros within the range of normal animals, whereas ros production by the cells isolated from the animals at higher level of parasitaemia (greater than 20%), was significantly higher even without stimulation with latex particles. ...19902191159
[the absence of an action of the pyrethroids deltamethrin and cypermethrin on mosquito susceptibility to the causative agent of malaria].mosquitos ae. aegypti and an. stephensi contact with sublethal doses of deltametrin and cypermetrin pyretroids at larval stage and in grown state, when diet includes sugar with pyretroids, had no influence on the sensitivity of survived females to malaria agents p. gallinaceum and p. berghei. mosquitos under experiment showed no obvious inhibition of the physiological condition in comparison with the control ones.19902191201
influence of pregnancy on the course of malaria in mice infected with plasmodium berghei.the course of malarial infection was compared in pregnant mice inoculated with plasmodium berghei at different stages of gestation. when 12-14 wk old, pregnant balb/c mice were inoculated with 1 x 10(6) of p. berghei nk65-infected red cells at gestation day 0, 2, 4, 6, 8, 10, 12, 14 or 16, the mice inoculated on gestation days 6-12 expired 6.5 days after inoculation compared to 9.5 days in non-pregnant mice. parasitemia in these pregnant mice increased rapidly on day 4 after inoculation and anem ...19902193152
sexual development in malarial parasites: gametocyte production, fertility and infectivity to the mosquito vector.using cloned lines of plasmodium berghei producing mixed asexual and sexual (clone 234l) and purely asexual (clone 233l) parasitaemias, the courses of parasitaemia, gametocytogenesis, exflagellation, ookinete production in vitro and mosquito infectivity have been followed. for clone 234l mosquito infectivity is maximal at day 3 and has ceased by day 6 post-infection. conversely, gametocytogenesis, exflagellation and ookinete production are at minimal levels at day 3 and rise to peaks between day ...19902194152
[free amino acid and synthesis of polyamines in plasmodium-berghei-infected rbc].the contents of free amino acids and the activity of ornithine decarboxylase in infected rbc of chloroquine-sensitive strain of plasmodium berghei(cs) were similar to those in chloroquine-resistant strain (cr). after treatment with chloroquine (10mg/kg im) no effect on the formation of free amino acids was found after 20th, but chloroquine (5mg/kg im) inhibited the enzymatic activity of the cs rbc by 79.6% whereas that of the cr by 55.7%. the contents of spermidine in cs and cr infected rbc were ...19902194691
hepatic superoxide dismutase, catalase and lipid peroxidation products in mastomys natalensis infected with plasmodium berghei.p. berghei infection in m. natalensis caused a significant reduction in the hepatic sod and catalase activities. cu-zn sod was more susceptible to infection than mn sod. the inhibition of enzyme activities was associated with marked increase in the levels of lipid peroxides, lipid hydroperoxides and conjugated dienes in infected m. natalensis. the alterations in the hepatic sod, catalase and lipid peroxides are related with the severity of infection.19902196223
identification of a putative plasmodium berghei (a rodent malaria parasite) reticulocyte receptor. 19902199274
typing of southern african isolates of plasmodium falciparum using monoclonal antibodies.antigenic diversity among 19 southern african isolates of plasmodium falciparum was demonstrated using a panel of 9 monoclonal antibodies. parasites obtained from single patients were heterogeneous. the antigen composition of 9 isolates was not stable with time in culture, particularly not with respect to 4 of the monoclonal antibodies. by the end of the investigation, 70% of isolates displayed an identical antigen pattern which was markedly different to any obtained in other parts of the world. ...19902200288
antimalarial activity of a 4',5'-unsaturated 5'-fluoroadenosine mechanism-based inhibitor of s-adenosyl-l-homocysteine hydrolase.a 4',5'-unsaturated 5'-fluoroadenosine inhibitor of s-adenosyl-l-homocysteine hydrolase (sah hydrolase; ec 3.3.1.1), mdl 28842, was found to inhibit markedly the growth of plasmodium falciparum in vitro and plasmodium berghei in mice. inhibition of p. berghei growth was associated with a large increase in the concentration of s-adenosyl-l-homocysteine (sah) in the erythrocytes of the mice treated with mdl 28842. this increase in sah was due apparently to inhibition of the mouse erythrocyte sah h ...19902200410
role of delayed type hypersensitivity responses in protection during chronic plasmodium berghei infection as evidenced by homing of radiolabelled bone marrow cells and contact sensitivity.a comparative study of specific and non-specific immunosuppression has been carried out in acute and chronic plasmodium berghei infected mice in an in vivo system. in our previous studies, immunosuppression during acute p. berghei infection was attributed to t lymphocytes when we studied modulation of blastogenic response of lymphocytes in an in vitro system. in the present study, delayed type hypersensitivity (dth) was evident from the homing of radiolabelled bone marrow cells into the delayed ...19902200902
glucose-6-phosphate dehydrogenase from plasmodium berghei: kinetic and electrophoretic characterization.evidence is given for the existence of a parasite-specific glucose-6-phosphate dehydrogenase in plasmodium berghei by characterization of its kinetic and electrophoretic properties. after separating the parasites from infected rbc the g6pd was purified by affinity chromatography with 2'5'-adp-sepharose 4b. in cellulose acetate electrophoresis malarial g6pd significantly differs from the red cell enzyme. the subunits of the parasite-specific g6pd have a molecular weight of 55 kd in contrast to 59 ...19902201291
nucleotide status in erythrocytes of rats infected with pl. berghei.nucleotide concentrations in erythrocytes of rats infected with plasmodium berghei were measured by ion-pair reversed-phase hplc. utp and gtp levels were higher in highly infected red blood cells obtained after density separation. the infected red blood cells possess higher hypoxanthine, adenine, and adenosine levels.19902201292
antimalarial activity of new water-soluble dihydroartemisinin derivatives. 3. aromatic amine analogues.a series of artemisinin (1) derivatives containing bromo and heterocyclic or aromatic amine functions was prepared in the search for analogues with good water solubility and high antimalarial activity. treatment of dihydroartemisinin (2a) with boron trifluoride etherate at room temperature gave the key intermediate, 9,10-dehydrodihydroartemisinin (3), which, on reaction with bromine, gave the dibromide 4. the latter was condensed with amines in anhydrous ch2cl2 at less than -10 degrees c to give ...19902202831
malaria parasitization and hormonal imbalance in virgin mice.the effect of the malaria parasite plasmodium berghei berghei on the estrus cycle was studied in rodents. it was observed that there was a delay at the proestrus phase of the estrus cycle. endocrinological evidence for lack of ovulation at estrus during infection was presented. although there was an elevation in the level of immune complexes and white blood cell counts, the red blood cell counts decreased as infection progressed. anal temperature recordings showed pyrexia. there was a wide diffe ...19902203871
cytochrome p-450 activity in malarial parasites and its possible relationship to chloroquine resistance.cytochrome p-450-dependent enzyme activities have been determined in malarial parasites. both plasmodium berghei and plasmodium falciparum parasites exhibited activity and these activities were greater in chloroquine resistant parasites than in sensitive strains. this enzyme activity could be induced by phenobarbitone and inhibited by specific inhibitors of the cytochrome p-450 family of enzymes. the significance of these observations in parasite drug resistance is discussed.19902204831
[combined action of pyronaridine and sulfadoxine/pyrimethamine against plasmodium berghei anka strain in mice].pyronaridine, a highly effective antimalarial drug, was synthesized and developed by this institute. in order to test whether the joint blood schizontocidal action of pyronaridine (pnd) and 2:1 mixture of sulfadoxine/pyrimethamine (sp) resulted in a potentiation or an additive effect, groups of p berghei anka strain-infected mice were treated with various single oral doses of pnd and sp. thin blood smears were made after 72 h and the parasitemia-negative rates were calculated. the ed50 values ob ...19902206014
[in vitro cultivation and scanning electron microscopic observation of plasmodium berghei].to compare the effects of sera on the growth of plasmodium berghei, the erythrocytic stages were cultured with rat serum, human umbilical cord serum, human b-type serum, rabbit serum, calf serum and calf serum with hypoxanthine respectively. the topography of the erythrocyte and parasite cultured with calf serum were observed before and 12, 20 and 28 hours after cultivation. all of the sera used did not effectively improve the long-term culture of p. berghei, regardless of some differences in sh ...19902208625
effect of prior eradication of plasmodium berghei infection on the foetal development and parasitaemic levels under the stress of pregnancy.pregnant mice infected on gestation day (gd) 13 with plasmodium berghei had similar rate of parasitaemia and mortality as non pregnant controls. 50% of pregnant infected mice had normal delivery, 20% had absorbed foetuses and 30% died before parturation. however, animals infected with p. berghei, treated with drugs (sulfadiazine or chloroquine) had normal foetal development. no recrudescence occurred in either of these groups of animals even under the stress of pregnancy indicating protection. p ...19902212635
low dosages of interleukin 1 protect mice against lethal cerebral malaria.in cerebral malaria, pathological changes can be found in the brain of infected people and in the brain of plasmodium berghei-infected mice. the pathogenesis of cerebral malaria in mice is believed to be due to an immunopathological reaction giving rise to an excessive production of cytokines such as interferon gamma (ifn-gamma) and tumor necrosis factor (tnf). we find that low doses of interleukin 1 (il-1) protect mice against cerebral malaria; il-1 also inhibits parasitemia. the il-1 effect on ...19902230643
[synthesis of 2-methyl-5-substituted phenoxy-primaquine and antimalarials activity].in searching for efficient, safe and radically curative agent and causal prophylactics for malaria, seven 2-methyl-5-substituted phenoxy-6-methoxy-8-(1-methyl-4-aminobutylamino)-quinolines (ii1-7) were synthesized and their antimalarial activities were compared with the corresponding 4-methyl substituted derivatives of primaquine. the starting material, 2-nitro-4-methoxy-5-bromo-acetanilide (iii), was prepared from p-methoxy aniline through acetylation, bromination and nitration. iii was then co ...19902239331
screening of artemisia absinthium for antimalarial effects on plasmodium berghei in mice: a preliminary report. 19902255213
an antigen specific to the liver stage of rodent malaria recognized by a monoclonal antibody.vaccines currently being evaluated against malaria are based on proteins derived from the blood, sporozoite and sexual stages. antigens from the liver stage, which is now recognized as the major target of protective sporozoite induced immunity, have received comparatively little attention. this paper describes the generation of a monoclonal antibody (moab), which recognizes an antigen specific to the liver stage of the rodent malaria plasmodium berghei. the antigen is expressed throughout liver ...19902255559
[the modelling of the multiple drug resistance of the malarial parasites. 1. the combined resistance of plasmodium berghei to chloroquine and fansidar].using a recurrent technique, p. berghei isolate resistant to chloroquine-fansidar combination is formed in golden hamsters. the isolate resistant to chloroquine-fansidar combination was 4 times less sensitive to chloroquine, 2 times less sensitive to fansidar and its combinations, 2 times less sensitive to sulfadoxine, 31 times less sensitive to pyrimethamine, as compared to the baseline isolate lnk65 p. berghei characterized by naturally reduced sensitivity to chloroquine.19902266909
prevention of malaria-induced foetal abnormalities following immunization of mice with plasmodium berghei merozoite antigen.pre-pregnancy immunization of swiss albino mice with merozoite antigen of p. berghei entrapped in multilamellar phosphatidyl choline liposomes resulted in (i) increased prepatent period, (ii) either no or low parasitaemic levels, (iii) reduced mortality, and (iv) normal foetal and placental development, upon challenge with p. berghei on 13th gestational day. the unimmunized animals which received either phosphate buffered saline or empty multilamellar phosphatidyl choline liposomes before pregna ...19902269510
potentiation of immune response against malaria in immunocompromised mice through glucan as an immunoadjuvant.untreated mice were fully immunocompetent but their treatment with various immunosuppressors rendered them immunocompromised with respect to one or the other or both limbs of immunity. both, humoral immune response or cell mediated immune response suppressed mice were only partially protected against the challenge with plasmodium berghei following their immunization. hydrocortisone treated mice, in which both types of immune responses were suppressed, were not protected against the challenge wit ...19902279761
significance of cytokine production and adhesion molecules in malarial immunopathology.the pathological expression in malaria infection depends largely on immunopathologic responses induced by the parasite. in the past few years, we have attempted to analyze mechanisms by which inappropriate immune response to some malarial antigens can generate major complications of malaria and particularly neurovascular lesions. to this end, we have undertaken a study aimed at a more precise definition of immunopathological parameters of malaria infection, and more particularly those involved i ...19902283148
tnf and plasmodium berghei anka-induced cerebral malaria.the cerebral pathology observed in plasmodium berghei anka-infected cba mice has been attributed to overproduction of tnf, the mice in which this syndrome is seen being those with the highest serum tnf levels. to investigate this further, we injected recombinant human tnf into malaria-primed mice to see if we could reproduce the cerebral changes observed in p. berghei anka infections. a range of doses, administered as a single or repeated injections, or via osmotic pumps, failed to reproduce the ...19902283149
malaria exoantigens induce tnf, are toxic and are blocked by t-independent antibody.the production of cytokines, including tumour necrosis factor (tnf), may be involved in the pathology of malaria, as well as in protection against the parasite. we have shown that parasite exoantigens induce the secretion of tnf in vitro and in vivo and kill mice made hypersensitive to tnf. they elicit t-independent antibody that inhibits their capacity to stimulate tnf production and protects against toxicity in vivo, and those of human and rodent parasites are serologically related. their acti ...19902283151
irradiated sporozoite vaccine induces cytotoxic t lymphocytes that recognize malaria antigens on the surface of infected hepatocytes.the observation that protective immunity induced by immunization with radiation attenuated plasmodium berghei and plasmodium yoelii sporozoites is dependent on cd8+ t lymphocytes in some strains of mice led us to speculate that immunization with sporozoites induces cytotoxic t lymphocytes (ctl) that recognize malaria antigens on the surface of malaria-infected hepatocytes. in this report we summarize a series of experiments that confirm this hypothesis. we first showed that when immune mice are ...19902283160
host-parasite interactions and immunity to irradiated sporozoites.we compare and contrast the results of immunizing mice with irradiated sporozoites of plasmodium berghei and plasmodium yoelii. host genetic control of protective immunity is different in the two rodent malarias. few mouse strains are strongly protected by p. yoelii sporozoites, while all are protected by p. berghei sporozoite immunization. the role of cd8+ t cells in the protective immune response to each of these malarias varies with the strain of mouse. moreover, a single strain will use a cd ...19902283161
non-cs pre-erythrocytic protective antigens.three novel non-cs antigens have been identified on p. falciparum and p. berghei sporozoites and exoerythrocytic parasites. csp-2 is a sporozoite surface protein common to p. falciparum and p. berghei that elicits antibody-mediated protection, and is also found within p. berghei ee parasites. lsa is a p. falciparum ee-specific antigen localized within the parasitophorous vacuole. lsa-2 is a p. berghei ee-specific antigen, localized on the parasitophorous vacuole membrane, that protected mice to ...19902283163
plasma orosomucoid metabolism and susceptibility to malarial infection in rodents.the effects of plasmodium berghei infection on liver function and plasma orosomucoid metabolism were investigated in wistar rats. infected rats with 20-25% parasitaemia manifested increased serum transaminase levels, hypoalbuminaemia and hypoproteinaemia. in spite of such indications of deranged liver function, the hepatic synthesis rate (as measured by 14c-amino acid incorporation) of seromucoids predominantly orosomucoid or alpha 1-acid glycoprotein) was increased by 73%. the circulating level ...19902283175
plasmodium yoelii nigeriensis circumsporozoite gene structure and its implications for the evolution of the repeat regions.the circumsporozoite (cs) gene encodes the most immunogenic component of the plasmodial sporozoites. the immunodominant epitope-encoding domain of the cs gene shows sequences that are repeated in tandem. a detailed analysis of the cs repeats of certain closely related malaria parasites (strains of plasmodium cynomolgi, plasmodium knowlesi, and plasmodium vivax) showed that they evolve rapidly yet are well conserved within the gene. we were interested in studying whether the cs repeats of plasmod ...19902290446
antimalarial activity of some 4-alkylamino 2/3 methoxy-4-aminodiphenyl sulphones.from a series of thirty six 2,3, n-substituted 4,4'-diaminodiphenyl sulphones studied for their suppressive activity in mice against blood induced erythrocytic stage of plasmodium berghei infection, six sulphones (1-6) showed 100% suppressive and curative activity at an intraperitoneal dose of 1 mg/kg x 4 days. these sulphones have been studied for their suppressive activity in still lower doses ranging from 1.0-0.25 mg/kg i.p. x 4 days and for their curative activity at 1 mg/kg i.p. x 4 days in ...19902292320
preliminary evaluation of extracts of alstonia scholaris bark for in vivo antimalarial activity in mice.the petroleum either extract and methanol extract of the bark of alstonia scholaris were found to be devoid of antiamalarial activity in mice infected with plasmodium berghei. however, a dose-dependent improvement of conditions and delayed mortality amongst animals receiving methanol extract of a. scholaris was noticed. studies with a. constricta and alstonine shall help resolve the antimalarial status of the bark in question.19902345460
role of dna-binding antibodies in kidney pathology associated with murine malaria infections.we performed a series of studies to examine the sequential development of nephritis during murine malaria infections and to define the role of dna-binding antibodies in the associated pathology. serum levels of these antibodies were assessed throughout acute and chronic malaria infections. increased levels of double-stranded dna- and single-stranded dna-binding antibodies were initially detected in mice infected with plasmodium vinckei or plasmodium yoelii nigeriensis during the middle stages of ...19902365456
plasmodium berghei: the antimalarial action of artemisinin and sodium artelinate in vivo and in vitro, studied by flow cytometry.sodium artelinate, a new water-soluble and relatively stable derivative of artemisinin, and its parent compound were tested for their antimalarial action. experiments were done in vitro with synchronous cultures of plasmodium berghei. the inhibition of growth by different concentrations of sodium artelinate and artemisinin was determined using flow cytometry. in vivo testing was done by subcutaneous injection of each drug in mice infected with p. berghei. sodium artelinate, being stable in aqueo ...19902404778
development of malaria parasites in mosquitoes fed with ookinetes suspended in defined media.information concerning the specific nutritional requirements of malarial parasites developing in the mosquito host has been difficult to obtain, owing primarily to the complex nature of the blood meal that accompanies the parasites and the lack of success in culturing the complete invertebrate cycle of plasmodium in vitro. the present report describes a blood-free system for infecting mosquitoes with ookinetes of plasmodium berghei and for allowing the latter to develop into infective sporozoite ...19902406164
sequence of the circumsporozoite gene of plasmodium berghei anka clone and nk65 strain. 19902406593
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