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Sample records for plasmodium berghei sporozoites

  1. In vitro infectivity of irradiated Plasmodium berghei sporozoites to cultured hepatoma cells

    International Nuclear Information System (INIS)

    Sigler, C.I.; Leland, P.; Hollingdale, M.R.

    1984-01-01

    The invasion of gamma-irradiated Plasmodium berghei sporozoites into cultured hepatoma cells and their transformation into trophozoites was similar to invasion and transformation of non-irradiated sporozoites. However, trophozoites from irradiated sporozoites did not further develop into schizonts, but persisted within the cells for up to 3 days. Sporozoite surface protective antigen was present in trophozoites from irradiated and non-irradiated sporozoites, suggesting that hepatocyte antigen processing may contribute to the induction of anti-malarial immunity

  2. Antisporozoite antibodies in mice immunized with irradiation-attenuated Plasmodium berghei sporozoites

    International Nuclear Information System (INIS)

    Hansen, R.; Silva, S.de; Strickland, G.T.

    1979-01-01

    Sera from NMRI/NIH mice were tested for the presence of IgM and IgG anti-sporozoite antibodies using the indirect fluorescent antibody test (IFAT). Both IgM and IgG antibody titres were related to the number of immunizations with irradiation-attenuated Plasmodium berghei sporozoites, and protection from challenge with subsequent non-attenuated sporozoites correlated with the pre-challenge antibody titre. Sera taken five days following challenge showed marked reductions in antibody titres, except for the group receiving the maximum (four) immunizations. Groups immunized with frozen sporozoites or mosquito tissue antigen developed neither antibodies to sporozoites nor protective immunity; nor did animals infected with parasitized blood. However, sera from mice immunized four times with attenuated sporozoites demonstrated IFA titres to blood-stage antigens. The results showed that both IgM and IgG anti-sporozoite antibodies could be detected in mice immunized with attenuated-sporozoites by IFAT, and that the antibody titres correlated with protective immunity. Cross reaction with blood-stage antigens occurred, but the test should still prove useful. (author)

  3. Baculovirus virions displaying Plasmodium berghei circumsporozoite protein protect mice against malaria sporozoite infection

    International Nuclear Information System (INIS)

    Yoshida, Shigeto; Kondoh, Daisuke; Arai, Eriko; Matsuoka, Hiroyuki; Seki, Chisato; Tanaka, Takao; Okada, Masaji; Ishii, Akira

    2003-01-01

    The display of foreign proteins on the surface of baculovirus virions has provided a tool for the analysis of protein-protein interactions and for cell-specific targeting in gene transfer applications. To evaluate the baculovirus display system as a vaccine vehicle, we have generated a recombinant baculovirus (AcNPV-CSPsurf) that displays rodent malaria Plasmodium berghei circumsporozoite protein (PbCSP) on the virion surface as a fusion protein with the major baculovirus envelope glycoprotein gp64. The PbCSP-gp64 fusion protein was incorporated and oligomerized on the virion surface and led to a 12-fold increase in the binding activity of AcNPV-CSPsurf virions to HepG2 cells. Immunization with adjuvant-free AcNPV-CSPsurf virions induced high levels of antibodies and gamma interferon-secreting cells against PbCSP and protected 60% of mice against sporozoite challenge. These data demonstrate that AcNPV-CSPsurf displays sporozoite-like PbCSP on the virion surface and possesses dual potentials as a malaria vaccine candidate and a liver-directed gene delivery vehicle

  4. Differences in susceptibility among mouse strains to infection with Plasmodium berghei (ANKA clone) sporozoites and its relationship to protection by gamma-irradiated sporozoites

    International Nuclear Information System (INIS)

    Jaffe, R.I.; Lowell, G.H.; Gordon, D.M.

    1990-01-01

    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 sporozoites. The outbred strain CD-1 was the most difficult to infect, requiring a challenge dose of 25,000 sporozoites/mouse in order to achieve a 100% infection rate. Mouse strains also demonstrated differences in their ability to be protected by intravenous immunization with gamma-irradiated sporozoites. A/J mice needed a minimum of 3 doses of irradiated sporozoites for protection against a challenge with 10,000 sporozoites. In contrast, BALB/c mice immunized with a single dose of 1,000 irradiated sporozoites are protected against a 10,000 sporozoite challenge. These data suggest that both infectivity and protection are genetically restricted and that susceptibility to infection may be inversely related to protection

  5. Genetically attenuated P36p-deficient Plasmodium berghei sporozoites confer long-lasting and partial cross-species protection

    NARCIS (Netherlands)

    Douradinha, Bruno; van Dijk, Melissa R.; Ataide, Ricardo; van Gemert, Geert-Jan; Thompson, Joanne; Franetich, Jean-Francois; Mazier, Dominique; Luty, Adrian J. F.; Sauerwein, Robert; Janse, Chris J.; Waters, Andrew P.; Mota, Maria M.

    2007-01-01

    Immunisation with live, radiation-attenuated sporozoites (RAS) or genetically attenuated sporozoites (GAS) of rodent plasmodial parasites protects against subsequent challenge infections. We recently showed that immunisation with Plasinodium berghei GAS that lack the microneme protein P36p protects

  6. The ETRAMP family member SEP2 is expressed throughout Plasmodium berghei life cycle and is released during sporozoite gliding motility.

    Science.gov (United States)

    Currà, Chiara; Di Luca, Marco; Picci, Leonardo; de Sousa Silva Gomes dos Santos, Carina; Siden-Kiamos, Inga; Pace, Tomasino; Ponzi, Marta

    2013-01-01

    The early transcribed membrane proteins ETRAMPs belong to a family of small, transmembrane molecules unique to Plasmodium parasite, which share a signal peptide followed by a short lysine-rich stretch, a transmembrane domain and a variable, highly charged C-terminal region. ETRAMPs are usually expressed in a stage-specific manner. In the blood stages they localize to the parasitophorous vacuole membrane and, in described cases, to vesicle-like structures exported to the host erythrocyte cytosol. Two family members of the rodent parasite Plasmodium berghei, uis3 and uis4, localize to secretory organelles of sporozoites and to the parasitophorous membrane vacuole of the liver stages. By the use of specific antibodies and the generation of transgenic lines, we showed that the P. berghei ETRAMP family member SEP2 is abundantly expressed in gametocytes as well as in mosquito and liver stages. In intracellular parasite stages, SEP2 is routed to the parasitophorous vacuole membrane while, in invasive ookinete and sporozoite stages, it localizes to the parasite surface. To date SEP2 is the only ETRAMP protein detected throughout the parasite life cycle. Furthermore, SEP2 is also released during gliding motility of salivary gland sporozoites. A limited number of proteins are known to be involved in this key function and the best characterized, the CSP and TRAP, are both promising transmission-blocking candidates. Our results suggest that ETRAMP members may be viewed as new potential candidates for malaria control.

  7. Distinct Prominent Roles for Enzymes of Plasmodium berghei Heme Biosynthesis in Sporozoite and Liver Stage Maturation

    Science.gov (United States)

    Matuschewski, Kai; Haussig, Joana M.

    2016-01-01

    Malarial parasites have evolved complex regulation of heme supply and disposal to adjust to heme-rich and -deprived host environments. In addition to its own pathway for heme biosynthesis, Plasmodium likely harbors mechanisms for heme scavenging from host erythrocytes. Elaborate compartmentalization of de novo heme synthesis into three subcellular locations, including the vestigial plastid organelle, indicates critical roles in life cycle progression. In this study, we systematically profile the essentiality of heme biosynthesis by targeted gene deletion of enzymes in early steps of this pathway. We show that disruption of endogenous heme biosynthesis leads to a first detectable defect in oocyst maturation and sporogony in the Anopheles vector, whereas blood stage propagation, colonization of mosquito midguts, or initiation of oocyst development occurs indistinguishably from that of wild-type parasites. Although sporozoites are produced by parasites lacking an intact pathway for heme biosynthesis, they are absent from mosquito salivary glands, indicative of a vital role for heme biosynthesis only in sporozoite maturation. Rescue of the first defect in sporogony permitted analysis of potential roles in liver stages. We show that liver stage parasites benefit from but do not strictly depend upon their own aminolevulinic acid synthase and that they can scavenge aminolevulinic acid from the host environment. Together, our experimental genetics analysis of Plasmodium enzymes for heme biosynthesis exemplifies remarkable shifts between the use of endogenous and host resources during life cycle progression. PMID:27600503

  8. Plasmodium Sporozoite Biology.

    Science.gov (United States)

    Frischknecht, Friedrich; Matuschewski, Kai

    2017-05-01

    Plasmodium sporozoite transmission is a critical population bottleneck in parasite life-cycle progression and, hence, a target for prophylactic drugs and vaccines. The recent progress of a candidate antisporozoite subunit vaccine formulation to licensure highlights the importance of sporozoite transmission intervention in the malaria control portfolio. Sporozoites colonize mosquito salivary glands, migrate through the skin, penetrate blood vessels, breach the liver sinusoid, and invade hepatocytes. Understanding the molecular and cellular mechanisms that mediate the remarkable sporozoite journey in the invertebrate vector and the vertebrate host can inform evidence-based next-generation drug development programs and immune intervention strategies. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  9. The development of exo-erythrocytic schizonts of Plasmodium berghei in vitro from gamma-irradiated and non-irradiated sporozoites: a study using confocal laser scanning microscopy

    International Nuclear Information System (INIS)

    Sinden, E.; Couchman, A.; Suhrbier, A.; Marsh, F.; Winger, L.; Ranawaka, G.

    1991-01-01

    Confocal scanning laser microscopy has been used to study the distribution of antigens expressed by the liver stages of Plasmodium berghei in cultured hepatoma cells. The 3-dimensional images obtained of intact parasites clearly show complex patterns of antigen expression not apparent when using conventional IFAT or immunoelectron microscopy. A liver-stage specific antigen (Pbl 1) was shown to be confined to the parasitophorous vacuole; the vacuole has extensive diverticulae extending into the host cell. Small parasites were detected for the first time in 'mature' cultures. These did not represent a distinct population, but the 'tail' of a broad continuum of parasite sizes. Irradiated sporozoites produce a transient population of slow-growing parasites which express a very limited range of antigens de novo in the invaded hepatoma cell. A comparison of the reactivity of normal EE parasites with anti-circumsporozoite antibody and with ant-Pbl 1 suggests that the former reagent may reliably be used to identify sporozoites invading host cells, but should not be used to determine the number of parasites that successfully undergo intrahepatic development. Anti-Pbl-1 indicates on 33% of invaded sporozoites identified by anti-CSP subsequently differentiate. (author)

  10. Plasmodium berghei sporozoite challenge of vaccinated BALB/c mice leads to the induction of humoral immunity and improved function of CD8(+) memory T cells

    Czech Academy of Sciences Publication Activity Database

    Tartz, S.; Deschermeier, Ch.; Retzlaff, S.; Heussler, V.; Šebo, Peter; Fleischer, B.; Jacobs, T.

    2013-01-01

    Roč. 43, č. 3 (2013), s. 693-704 ISSN 0014-2980 R&D Projects: GA ČR GA310/08/0447 Institutional research plan: CEZ:AV0Z50200510 Keywords : CD8+Tcells * Plasmodium * Sporozoites Subject RIV: EE - Microbiology, Virology Impact factor: 4.518, year: 2013

  11. Species-specific escape of Plasmodium sporozoites from oocysts of avian, rodent, and human malarial parasites.

    Science.gov (United States)

    Orfano, Alessandra S; Nacif-Pimenta, Rafael; Duarte, Ana P M; Villegas, Luis M; Rodrigues, Nilton B; Pinto, Luciana C; Campos, Keillen M M; Pinilla, Yudi T; Chaves, Bárbara; Barbosa Guerra, Maria G V; Monteiro, Wuelton M; Smith, Ryan C; Molina-Cruz, Alvaro; Lacerda, Marcus V G; Secundino, Nágila F C; Jacobs-Lorena, Marcelo; Barillas-Mury, Carolina; Pimenta, Paulo F P

    2016-08-02

    Malaria is transmitted when an infected mosquito delivers Plasmodium sporozoites into a vertebrate host. There are many species of Plasmodium and, in general, the infection is host-specific. For example, Plasmodium gallinaceum is an avian parasite, while Plasmodium berghei infects mice. These two parasites have been extensively used as experimental models of malaria transmission. Plasmodium falciparum and Plasmodium vivax are the most important agents of human malaria, a life-threatening disease of global importance. To complete their life cycle, Plasmodium parasites must traverse the mosquito midgut and form an oocyst that will divide continuously. Mature oocysts release thousands of sporozoites into the mosquito haemolymph that must reach the salivary gland to infect a new vertebrate host. The current understanding of the biology of oocyst formation and sporozoite release is mostly based on experimental infections with P. berghei, and the conclusions are generalized to other Plasmodium species that infect humans without further morphological analyses. Here, it is described the microanatomy of sporozoite escape from oocysts of four Plasmodium species: the two laboratory models, P. gallinaceum and P. berghei, and the two main species that cause malaria in humans, P. vivax and P. falciparum. It was found that sporozoites have species-specific mechanisms of escape from the oocyst. The two model species of Plasmodium had a common mechanism, in which the oocyst wall breaks down before sporozoites emerge. In contrast, P. vivax and P. falciparum sporozoites show a dynamic escape mechanism from the oocyst via polarized propulsion. This study demonstrated that Plasmodium species do not share a common mechanism of sporozoite escape, as previously thought, but show complex and species-specific mechanisms. In addition, the knowledge of this phenomenon in human Plasmodium can facilitate transmission-blocking studies and not those ones only based on the murine and avian models.

  12. Gene expression changes in the salivary glands of Anopheles coluzzii elicited by Plasmodium berghei infection

    Czech Academy of Sciences Publication Activity Database

    Pinheiro-Silva, R.; Borges, L.; Coelho, L.P.; Cabezas-Cruz, A.; Valdés, James J.; do Rosário, V.; de la Fuente, J.; Domingos, A.

    2015-01-01

    Roč. 8, SEP 23 2015 (2015), s. 485 ISSN 1756-3305 Institutional support: RVO:60077344 Keywords : Anopheles coluzzii * Salivary glands * Plasmodium berghei * Sporozoite * RNA-seq * Glucose transporter * RNAi Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.234, year: 2015

  13. Proteomic profiling of Plasmodium sporozoite maturation identifies new proteins essential for parasite development and infectivity

    DEFF Research Database (Denmark)

    Lasonder, Edwin; Janse, Chris J; van Gemert, Geert-Jan

    2008-01-01

    Plasmodium falciparum sporozoites that develop and mature inside an Anopheles mosquito initiate a malaria infection in humans. Here we report the first proteomic comparison of different parasite stages from the mosquito -- early and late oocysts containing midgut sporozoites, and the mature...... whose annotation suggest an involvement in sporozoite maturation, motility, infection of the human host and associated metabolic adjustments. Analyses of proteins identified in the P. falciparum sporozoite proteomes by orthologous gene disruption in the rodent malaria parasite, P. berghei, revealed...... three previously uncharacterized Plasmodium proteins that appear to be essential for sporozoite development at distinct points of maturation in the mosquito. This study sheds light on the development and maturation of the malaria parasite in an Anopheles mosquito and also identifies proteins that may...

  14. A cysteine protease inhibitor of plasmodium berghei is essential for exo-erythrocytic development.

    Directory of Open Access Journals (Sweden)

    Christine Lehmann

    2014-08-01

    Full Text Available Plasmodium parasites express a potent inhibitor of cysteine proteases (ICP throughout their life cycle. To analyze the role of ICP in different life cycle stages, we generated a stage-specific knockout of the Plasmodium berghei ICP (PbICP. Excision of the pbicb gene occurred in infective sporozoites and resulted in impaired sporozoite invasion of hepatocytes, despite residual PbICP protein being detectable in sporozoites. The vast majority of these parasites invading a cultured hepatocyte cell line did not develop to mature liver stages, but the few that successfully developed hepatic merozoites were able to initiate a blood stage infection in mice. These blood stage parasites, now completely lacking PbICP, exhibited an attenuated phenotype but were able to infect mosquitoes and develop to the oocyst stage. However, PbICP-negative sporozoites liberated from oocysts exhibited defective motility and invaded mosquito salivary glands in low numbers. They were also unable to invade hepatocytes, confirming that control of cysteine protease activity is of critical importance for sporozoites. Importantly, transfection of PbICP-knockout parasites with a pbicp-gfp construct fully reversed these defects. Taken together, in P. berghei this inhibitor of the ICP family is essential for sporozoite motility but also appears to play a role during parasite development in hepatocytes and erythrocytes.

  15. The Plasmodium protein P113 supports efficient sporozoite to liver stage conversion in vivo.

    Science.gov (United States)

    Offeddu, Vittoria; Rauch, Manuel; Silvie, Olivier; Matuschewski, Kai

    2014-02-01

    Invasive stages of Plasmodium parasites possess distinct integral and peripheral membrane proteins that mediate host cell attachment and invasion. P113 is an abundant protein in detergent-resistant high molecular weight complexes in Plasmodium schizonts, but is unusual since expression extends to gametocytes and sporozoites. In this study, we tested whether P113 performs important functions for parasite propagation in Plasmodium berghei. We show that pre-erythrocytic expression of P113 displays key signatures of upregulated in infectious sporozoites (UIS) genes, including control by the liver stage master regulator SLARP. Targeted gene deletion resulted in viable blood stage parasites that displayed no signs of blood stage growth defects. p113(-) parasites propagated normally through the life cycle until mature sporozoites, but displayed defects during natural sporozoite transmission, leading to a delay to patency in infected animals. By comparative in vitro and in vivo analysis of pre-erythrocytic development and using a xeno-diagnostic test we show that ablation of P113 results in lower sporozoite to liver stage conversion and, as a consequence, reduced merozoite output in vivo, without delaying liver stage development. We conclude that p113 is dispensable for Plasmodium life cycle progression and plays auxiliary roles during pre-erythrocytic development. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. A sporozoite asparagine-rich protein controls initiation of Plasmodium liver stage development.

    Directory of Open Access Journals (Sweden)

    Olivier Silvie

    2008-06-01

    Full Text Available Plasmodium sporozoites invade host hepatocytes and develop as liver stages (LS before the onset of erythrocytic infection and malaria symptoms. LS are clinically silent, and constitute ideal targets for causal prophylactic drugs and vaccines. The molecular and cellular mechanisms underlying LS development remain poorly characterized. Here we describe a conserved Plasmodium asparagine-rich protein that is specifically expressed in sporozoites and liver stages. Gene disruption in Plasmodium berghei results in complete loss of sporozoite infectivity to rodents, due to early developmental arrest after invasion of hepatocytes. Mutant sporozoites productively invade host cells by forming a parasitophorous vacuole (PV, but subsequent remodelling of the membrane of the PV (PVM is impaired as a consequence of dramatic down-regulation of genes encoding PVM-resident proteins. These early arrested mutants confer only limited protective immunity in immunized animals. Our results demonstrate the role of an asparagine-rich protein as a key regulator of Plasmodium sporozoite gene expression and LS development, and suggest a requirement of partial LS maturation to induce optimal protective immune responses against malaria pre-erythrocytic stages. These findings have important implications for the development of genetically attenuated parasites as a vaccine approach.

  17. Wild Anopheles funestus mosquito genotypes are permissive for infection with the rodent malaria parasite, Plasmodium berghei.

    Directory of Open Access Journals (Sweden)

    Jiannong Xu

    Full Text Available Malaria parasites undergo complex developmental transitions within the mosquito vector. A commonly used laboratory model for studies of mosquito-malaria interaction is the rodent parasite, P. berghei. Anopheles funestus is a major malaria vector in sub-Saharan Africa but has received less attention than the sympatric species, Anopheles gambiae. The imminent completion of the A. funestus genome sequence will provide currently lacking molecular tools to describe malaria parasite interactions in this mosquito, but previous reports suggested that A. funestus is not permissive for P. berghei development.An A. funestus population was generated in the laboratory by capturing female wild mosquitoes in Mali, allowing them to oviposit, and rearing the eggs to adults. These F1 progeny of wild mosquitoes were allowed to feed on mice infected with a fluorescent P. berghei strain. Fluorescence microscopy was used to track parasite development inside the mosquito, salivary gland sporozoites were tested for infectivity to mice, and parasite development in A. funestus was compared to A. gambiae.P. berghei oocysts were detectable on A. funestus midguts by 7 days post-infection. By 18-20 days post-infection, sporozoites had invaded the median and distal lateral lobes of the salivary glands, and hemocoel sporozoites were observed in the hemolymph. Mosquitoes were capable of infecting mice via bite, demonstrating that A. funestus supports the complete life cycle of P. berghei. In a random sample of wild mosquito genotypes, A. funestus prevalence of infection and the characteristics of parasite development were similar to that observed in A. gambiae-P. berghei infections.The data presented in this study establish an experimental laboratory model for Plasmodium infection of A. funestus, an important vector of human malaria. Studying A. funestus-Plasmodium interactions is now feasible in a laboratory setting. This information lays the groundwork for exploitation of the

  18. Immunization with Pre-Erythrocytic Antigen CelTOS from Plasmodium falciparum Elicits Cross-Species Protection against Heterologous Challenge with Plasmodium berghei

    Science.gov (United States)

    2010-08-01

    or the early liver-stages of the mammalian life cycle . One of these antigens is the cell-traversal protein for ookinetes and sporozoites (CelTOS...Immunization with Pre-Erythrocytic Antigen CelTOS from Plasmodium falciparum Elicits Cross-Species Protection against Heterologous Challenge with... Plasmodium berghei Elke S. Bergmann-Leitner1*, Ryan M. Mease1, Patricia De La Vega1, Tatyana Savranskaya2, Mark Polhemus1, Christian Ockenhouse1, Evelina

  19. Long term protection after immunization with P. berghei sporozoites correlates with sustained IFNgamma responses of hepatic CD8+ memory T cells.

    NARCIS (Netherlands)

    Nganou Makamdop, C.K.; Gemert, G.J.A. van; Arens, T.; Hermsen, C.C.; Sauerwein, R.W.

    2012-01-01

    Protection against P. berghei malaria can successfully be induced in mice by immunization with both radiation attenuated sporozoites (RAS) arresting early during liver stage development, or sporozoites combined with chloroquine chemoprophylaxis (CPS), resulting in complete intra-hepatic parasite

  20. Hepatocyte CD81 is required for Plasmodium falciparum and Plasmodium yoelii sporozoite infectivity.

    NARCIS (Netherlands)

    Silvie, O.; Rubinstein, E.; Franetich, J.F.; Prenant, M.; Belnoue, E.; Renia, L.; Hannoun, L.; Eling, W.M.C.; Levy, S.; Boucheix, C.; Mazier, D.

    2003-01-01

    Plasmodium sporozoites are transmitted through the bite of infected mosquitoes and first invade the liver of the mammalian host, as an obligatory step of the life cycle of the malaria parasite. Within hepatocytes, Plasmodium sporozoites reside in a membrane-bound vacuole, where they differentiate

  1. Plasmodium sporozoites trickle out of the injection site.

    Science.gov (United States)

    Yamauchi, Lucy Megumi; Coppi, Alida; Snounou, Georges; Sinnis, Photini

    2007-05-01

    Plasmodium sporozoites make a remarkable journey from the skin, where they are deposited by an infected Anopheline mosquito, to the liver, where they invade hepatocytes and develop into exoerythrocytic stages. Although much work has been done to elucidate the molecular mechanisms by which sporozoites invade hepatocytes, little is known about the interactions between host and parasite before the sporozoite enters the blood circulation. It has always been assumed that sporozoites rapidly exit the injection site, making their interactions with the host at this site, brief and difficult to study. Using quantitative PCR, we determined the kinetics with which sporozoites leave the injection site and arrive in the liver and found that the majority of infective sporozoites remain in the skin for hours. We then performed sub-inoculation experiments which confirmed these findings and showed that the pattern of sporozoite exit from the injection site resembles a slow trickle. Last, we found that drainage of approximately 20% of the sporozoite inoculum to the lymphatics is associated with a significant enlargement of the draining lymph node, a response not observed after intravenous inoculation. These findings indicate that there is ample time for host and parasite to interact at the inoculation site and are of relevance to the pre-erythrocytic stage malaria vaccine effort.

  2. Protective immune mechanisms against pre-erythrocytic forms of Plasmodium berghei depend on the target antigen

    Directory of Open Access Journals (Sweden)

    Elke S. Bergmann-Leitner

    2014-01-01

    Full Text Available Pre-erythrocytic malaria vaccines are believed to either stop the injected sporozoites from reaching the liver or to direct cellular immune responses towards eliminating infected hepatocytes. The present study reveals for the first time the anatomical sites at which these immune mechanisms act against the malaria parasites. To determine the mechanisms leading to protection mediated by two previously characterized vaccines against either the circumsporozoite protein (CSP or the cell traversal protein for ookinetes and sporozoites (CelTOS, mice were immunized and subsequently challenged by subcutaneous injection of salivary gland sporozoites of luciferase-transgenic Plasmodium berghei parasites. The In Vivo Imaging System (IVIS was used to identify the anatomical site where the vaccine-induced immune response eliminates sporozoites after injection. The data demonstrate that CSP-based immunity acts at the site of infection (skin whereas CelTOS-based immunity is only partially efficient in the skin and allows reduced levels of liver infection that can be subsequently cleared. The results of this study challenge assumptions regarding CSP-mediated immune mechanisms and call into question the validity of some commonly used assays to evaluate anti-CSP immune responses. The knowledge of the mechanism and events leading to infection or immune defense will guide supportive treatment with drugs or combination therapies and thus accelerate the development of effective antimalarial strategies.

  3. Antiplasmodial Effect of Anthocleista vogelii on Albino Mice Experimentally Infected with Plasmodium berghei berghei (NK 65

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    Lebari Barine Gboeloh

    2014-01-01

    Full Text Available The objective of the present study was to investigate the antiplasmodial effect of the ethanolic stem bark extract of Anthocleista vogelii at different doses in albino mice infected with Plasmodium berghei berghei (NK 65. Thirty-six mice were divided into six groups of six mice each. Five groups (B1–B3, D, and G were infected with Plasmodium berghei berghei parasitized red blood cells. Groups D, H, and G served as the controls. Six days after infection, mice in groups B1, B2, and B3 were treated orally with 100, 200, and 400 mg/kg body weight of Anthocleista vogelii, respectively, for six executive days. Group D was treated with 5 mg/kg body weight of chloroquine while Group G was given distilled water. Group H was not infected and was not treated. It served as the normal control. The extracts exhibited significant (P<0.05 dose-dependent chemosuppression of P. berghei. The extract exhibited average chemosuppressive effects of 48.5%, 78.5%, and 86.6% at dose levels of 100, 200, and 400 mg/kg body weight, respectively. Phytochemical screening of the plant extract revealed the presence of saponins, cardiac glycosides, flavonoids, terpenes, alkaloids, and steroid. The acute toxicity (LD50 of the plant was estimated to be 3162 mg/kg body weight. It showed that the stem bark of A. vogelii possesses antiplasmodial property.

  4. A rodent malarial model of Plasmodium berghei for the development ...

    African Journals Online (AJOL)

    A rodent malarial model of Plasmodium berghei for the development of pyrimethamine and sulphadoxine-pyrimethamine resistant malaria in mice. ... course approach with 125/6.25mg/kg S/P. The stability of resistance phenotypes, parasite pathogenic disposition and host leukocyte response were also investigated.

  5. Antibody and B cell responses to Plasmodium sporozoites

    Directory of Open Access Journals (Sweden)

    Johanna N Dups

    2014-11-01

    Full Text Available Antibodies are capable of blocking infection of the liver by Plasmodium sporozoites. Accordingly the induction of anti-sporozoite antibodies is a major aim of various vaccine approaches to malaria. In recent years our knowledge of the specificity and quantities of antibodies required for protection has been greatly expanded by clinical trials of various whole sporozoite and subunit vaccines. Moreover, the development of humanized mouse models and transgenic parasites have also aided our ability to assess the specificity of antibodies and their ability to block infection. Nonetheless, considerable gaps remain in our knowledge - in particular in understanding what antigens are recognized by infection blocking antibodies and in knowing how we can induce robust, long-lived antibody responses. Maintaining high levels of circulating antibodies is likely to be of primary importance, as antibodies must block infection in the short time it takes for sporozoites to reach the liver from the skin. It is clear that a better understanding of the development of protective B cell-mediated immunity will aid the development and refinement of malaria vaccines.

  6. Plasmodium knowlesi Sporozoite Antigen: Expression by Infectious Recombinant Vaccinia Virus

    Science.gov (United States)

    Smith, Geoffrey L.; Godson, G. Nigel; Nussenzweig, Victor; Nussenzweig, Ruth S.; Barnwell, John; Moss, Bernard

    1984-04-01

    The gene coding for the circumsporozoite antigen of the malaria parasite Plasmodium knowlesi was inserted into the vaccinia virus genome under the control of a defined vaccinia virus promoter. Cells infected with the recombinant virus synthesized polypeptides of 53,000 to 56,000 daltons that reacted with monoclonal antibody against the repeating epitope of the malaria protein. Furthermore, rabbits vaccinated with the recombinant virus produced antibodies that bound specifically to sporozoites. These data provide evidence for expression of a cloned malaria gene in mammalian cells and illustrate the potential of vaccinia virus recombinants as live malaria vaccines.

  7. Comparative Plasmodium gene overexpression reveals distinct perturbation of sporozoite transmission by profilin.

    Science.gov (United States)

    Sato, Yuko; Hliscs, Marion; Dunst, Josefine; Goosmann, Christian; Brinkmann, Volker; Montagna, Georgina N; Matuschewski, Kai

    2016-07-15

    Plasmodium relies on actin-based motility to migrate from the site of infection and invade target cells. Using a substrate-dependent gliding locomotion, sporozoites are able to move at fast speed (1-3 μm/s). This motility relies on a minimal set of actin regulatory proteins and occurs in the absence of detectable filamentous actin (F-actin). Here we report an overexpression strategy to investigate whether perturbations of F-actin steady-state levels affect gliding locomotion and host invasion. We selected two vital Plasmodium berghei G-actin-binding proteins, C-CAP and profilin, in combination with three stage-specific promoters and mapped the phenotypes afforded by overexpression in all three extracellular motile stages. We show that in merozoites and ookinetes, additional expression does not impair life cycle progression. In marked contrast, overexpression of C-CAP and profilin in sporozoites impairs circular gliding motility and salivary gland invasion. The propensity for productive motility correlates with actin accumulation at the parasite tip, as revealed by combinations of an actin-stabilizing drug and transgenic parasites. Strong expression of profilin, but not C-CAP, resulted in complete life cycle arrest. Comparative overexpression is an alternative experimental genetic strategy to study essential genes and reveals effects of regulatory imbalances that are not uncovered from deletion-mutant phenotyping. © 2016 Sato et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  8. Conformational co-dependence between Plasmodium berghei LCCL proteins promotes complex formation and stability.

    Science.gov (United States)

    Saeed, Sadia; Tremp, Annie Z; Dessens, Johannes T

    2012-10-01

    Malaria parasites express a conserved family of LCCL-lectin adhesive-like domain proteins (LAPs) that have essential functions in sporozoite transmission. In Plasmodium falciparum all six family members are expressed in gametocytes and form a multi-protein complex. Intriguingly, knockout of P. falciparum LCCL proteins adversely affects expression of other family members at protein, but not at mRNA level, a phenomenon termed co-dependent expression. Here, we investigate this in Plasmodium berghei by crossing a PbLAP1 null mutant parasite with a parasite line expressing GFP-tagged PbLAP3 that displays strong fluorescence in gametocytes. Selected and validated double mutants show normal synthesis and subcellular localization of PbLAP3::GFP. However, GFP-based fluorescence is dramatically reduced without PbLAP1 present, indicating that PbLAP1 and PbLAP3 interact. Moreover, absence of PbLAP1 markedly reduces the half-life of PbLAP3, consistent with a scenario of misfolding. These findings unveil a potential mechanism of conformational interdependence that facilitates assembly and stability of the functional LCCL protein complex. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Proteomic profiling of Plasmodium sporozoite maturation identifies new proteins essential for parasite development and infectivity.

    NARCIS (Netherlands)

    Lasonder, E.; Janse, C.J.; Gemert, G.J.A. van; Mair, G.R.; Vermunt, A.M.W.; Douradinha, B.G.; Noort, V. van; Huynen, M.A.; Luty, A.J.F.; Kroeze, H.; Khan, S.M.; Sauerwein, R.W.; Waters, A.P.; Mann, M.; Stunnenberg, H.G.

    2008-01-01

    Plasmodium falciparum sporozoites that develop and mature inside an Anopheles mosquito initiate a malaria infection in humans. Here we report the first proteomic comparison of different parasite stages from the mosquito -- early and late oocysts containing midgut sporozoites, and the mature,

  10. Memory B-Cell and Antibody Responses Induced by Plasmodium falciparum Sporozoite Immunization

    NARCIS (Netherlands)

    Nahrendorf, W.; Scholzen, A.; Bijker, E.M.; Teirlinck, A.C.; Bastiaens, G.J.H.; Schats, R.; Hermsen, C.C.; Visser, L.G.; Langhorne, J.; Sauerwein, R.W.

    2014-01-01

    BACKGROUND: Immunization of healthy volunteers during receipt of chemoprophylaxis with Plasmodium falciparum sporozoites (CPS-immunization) induces sterile protection from malaria. Antibody responses have long been known to contribute to naturally acquired immunity against malaria, but their

  11. Gene disruption reveals a dispensable role for plasmepsin VII in the Plasmodium berghei life cycle.

    Science.gov (United States)

    Mastan, Babu S; Kumari, Anchala; Gupta, Dinesh; Mishra, Satish; Kumar, Kota Arun

    2014-06-01

    Plasmepsins (PM), aspartic proteases of Plasmodium, comprises a family of ten proteins that perform critical functions in Plasmodium life cycle. Except VII and VIII, functions of the remaining plasmepsin members have been well characterized. Here, we have generated a mutant parasite lacking PM VII in Plasmodium berghei using reverse genetics approach. Systematic comparison of growth kinetics and infection in both mosquito and vertebrate host revealed that PM VII depleted mutants exhibited no defects in development and progressed normally throughout the parasite life cycle. These studies suggest a dispensable role for PM VII in Plasmodium berghei life cycle. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Development of a chimeric Plasmodium berghei strain expressing the repeat region of the P. vivax circumsporozoite protein for in vivo evaluation of vaccine efficacy.

    Science.gov (United States)

    Espinosa, Diego A; Yadava, Anjali; Angov, Evelina; Maurizio, Paul L; Ockenhouse, Christian F; Zavala, Fidel

    2013-08-01

    The development of vaccine candidates against Plasmodium vivax-the most geographically widespread human malaria species-is challenged by technical difficulties, such as the lack of in vitro culture systems and availability of animal models. Chimeric rodent Plasmodium parasites are safe and useful tools for the preclinical evaluation of new vaccine formulations. We report the successful development and characterization of chimeric Plasmodium berghei parasites bearing the type I repeat region of P. vivax circumsporozoite protein (CSP). The P. berghei-P. vivax chimeric strain develops normally in mosquitoes and produces highly infectious sporozoites that produce patent infection in mice that are exposed to the bites of as few as 3 P. berghei-P. vivax-infected mosquitoes. Using this transgenic parasite, we demonstrate that monoclonal and polyclonal antibodies against P. vivax CSP strongly inhibit parasite infection and thus support the notion that these antibodies play an important role in protective immunity. The chimeric parasites we developed represent a robust model for evaluating protective immune responses against P. vivax vaccines based on CSP.

  13. Experimental vaccination of chicks with Plasmodium gallinaceum sporozoites. I. Circumsporozoite proteins are expressed by sporozoites recovered from both salivary glands and midguts of mosquitoes

    International Nuclear Information System (INIS)

    Daher, V.R.; Krettli, A.U.

    1987-01-01

    Immunogenicity of Plasmodium gallinaceum sporozoites for chicks and their in vitro reactivity with normal and specific immune sera were studied. Two sporozoite populations recovered from experimentally infected Aedes fluviatilis were used: sporozoites from salivary glands and sporozoites from midgut oocysts. Populations seven to nine days old of sporozoites recovered from salivary glands were infective for all chicks until the chicks were three weeks old; however, sporozoites recovered from midguts containing oocysts infected these chicks only if isolated on days 8-9, but not on day 7 after the mosquitoes' infective blood meal. Infectivity of the sporozoites was lost after exposure to ultraviolet (UV) light (30 min) or X-rays (13 krad). Inactivated sporozoites from both sources proved highly immunogenic to chicks that were immunized by several intravenous or intramuscular injections. These parasites elicited a strong humoral immune response in the chicks, as measured by the circumsporozoite precipitation (CSP) reaction. The levels of the CSP antibodies were similar with sporozoites from both sources, there being no detectable differences in the percentage of reactive sporozoites or the intensity of the CSP reaction with sera containing antibodies to either sporozoites from salivary glands or sporozoites from oocysts. These results provide the first evidence that avian malaria sporozoites express the circumsporozoite protein that has been extensively characterized in mammalian malaria (rodent, simian, human sporozoites). Furthermore, we observed that the yields of sporozoites obtained from mosquito midguts, on days 8 and 9 of the P. gallinaceum infection, were at least twice as great as those obtained by salivary gland dissection, even 20 days after a blood meal

  14. Heterologous Protection against Malaria after Immunization with Plasmodium falciparum Sporozoites.

    Directory of Open Access Journals (Sweden)

    Remko Schats

    Full Text Available Sterile protection in >90% of volunteers against homologous Plasmodium falciparum infection has been achieved only using the controlled human malaria infection (CHMI model. This efficient model involves whole parasite immunizations under chloroquine prophylaxis (CPS-immunization, requiring only 30-45 mosquitoes bites infected with P. falciparum-sporozoites. Given the large diversity of P. falciparum parasites, it is essential to assess protection against heterologous parasite strains.In an open-label follow-up study, 16 volunteers previously CPS-immunized and challenged with P. falciparum NF54 (West-Africa in a dose de-escalation and challenge trial were re-challenged with clone NF135.C10 (Cambodia at 14 months after the last immunization (NCT01660854.Two out of thirteen NF54 protected volunteers previously fully protected against NF54 were also fully protected against NF135.C10, while 11/13 showed a delayed patency (median prepatent period of 10.5 days (range 9.0-15.5 versus 8.5 days in 5 malaria-naïve controls (p = 0.0005. Analysis of patency by qPCR indicated a 91 to >99% estimated reduction of liver parasite load in 7/11 partially protected subjects. Three volunteers previously not protected against NF54, were also not protected against NF135.C10.This study shows that CPS-immunization can induce heterologous protection for a period of more than one year, which is a further impetus for clinical development of whole parasite vaccines.Clinicaltrials.gov NCT01660854.

  15. Identification of a Novel CD8 T Cell Epitope Derived from Plasmodium berghei Protective Liver-Stage Antigen

    Directory of Open Access Journals (Sweden)

    Alexander Pichugin

    2018-01-01

    Full Text Available We recently identified novel Plasmodium berghei (Pb liver stage (LS genes that as DNA vaccines significantly reduce Pb LS parasite burden (LPB in C57Bl/6 (B6 mice through a mechanism mediated, in part, by CD8 T cells. In this study, we sought to determine fine antigen (Ag specificities of CD8 T cells that target LS malaria parasites. Guided by algorithms for predicting MHC class I-restricted epitopes, we ranked sequences of 32 Pb LS Ags and selected ~400 peptides restricted by mouse H-2Kb and H-2Db alleles for analysis in the high-throughput method of caged MHC class I-tetramer technology. We identified a 9-mer H-2Kb restricted CD8 T cell epitope, Kb-17, which specifically recognized and activated CD8 T cell responses in B6 mice immunized with Pb radiation-attenuated sporozoites (RAS and challenged with infectious sporozoites (spz. The Kb-17 peptide is derived from the recently described novel protective Pb LS Ag, PBANKA_1031000 (MIF4G-like protein. Notably, immunization with the Kb-17 epitope delivered in the form of a minigene in the adenovirus serotype 5 vector reduced LPB in mice infected with spz. On the basis of our results, Kb-17 peptide was available for CD8 T cell activation and recall following immunization with Pb RAS and challenge with infectious spz. The identification of a novel MHC class I-restricted epitope from the protective Pb LS Ag, MIF4G-like protein, is crucial for advancing our understanding of immune responses to Plasmodium and by extension, toward vaccine development against malaria.

  16. Long term protection after immunization with P. berghei sporozoites correlates with sustained IFNγ responses of hepatic CD8+ memory T cells.

    Science.gov (United States)

    Nganou-Makamdop, Krystelle; van Gemert, Geert-Jan; Arens, Theo; Hermsen, Cornelus C; Sauerwein, Robert W

    2012-01-01

    Protection against P. berghei malaria can successfully be induced in mice by immunization with both radiation attenuated sporozoites (RAS) arresting early during liver stage development, or sporozoites combined with chloroquine chemoprophylaxis (CPS), resulting in complete intra-hepatic parasite development before killing of blood-stages by chloroquine takes place. We assessed the longevity of protective cellular immune responses by RAS and CPS P. berghei immunization of C57BL/6j mice. Strong effector and memory (T(EM)) CD8+ T cell responses were induced predominantly in the liver of both RAS and CPS immunized mice while CD4+ T cells with memory phenotype remained at base line levels. Compared to unprotected naïve mice, we found high sporozoite-specific IFNγ ex vivo responses that associated with induced levels of in vivo CD8+ T(EM) cells in the liver but not spleen. Long term evaluation over a period of 9 months showed a decline of malaria-specific IFNγ responses in RAS and CPS mice that significantly correlated with loss of protection (r(2) = 0.60, pmemory CD8+ T cells could be boosted by re-exposure to wild-type sporozoites. Our data show that sustainable protection against malaria associates with distinct intra-hepatic immune responses characterized by strong IFNγ producing CD8+ memory T cells.

  17. Long term protection after immunization with P. berghei sporozoites correlates with sustained IFNγ responses of hepatic CD8+ memory T cells.

    Directory of Open Access Journals (Sweden)

    Krystelle Nganou-Makamdop

    Full Text Available Protection against P. berghei malaria can successfully be induced in mice by immunization with both radiation attenuated sporozoites (RAS arresting early during liver stage development, or sporozoites combined with chloroquine chemoprophylaxis (CPS, resulting in complete intra-hepatic parasite development before killing of blood-stages by chloroquine takes place. We assessed the longevity of protective cellular immune responses by RAS and CPS P. berghei immunization of C57BL/6j mice. Strong effector and memory (T(EM CD8+ T cell responses were induced predominantly in the liver of both RAS and CPS immunized mice while CD4+ T cells with memory phenotype remained at base line levels. Compared to unprotected naïve mice, we found high sporozoite-specific IFNγ ex vivo responses that associated with induced levels of in vivo CD8+ T(EM cells in the liver but not spleen. Long term evaluation over a period of 9 months showed a decline of malaria-specific IFNγ responses in RAS and CPS mice that significantly correlated with loss of protection (r(2 = 0.60, p<0.0001. The reducing IFNγ response by hepatic memory CD8+ T cells could be boosted by re-exposure to wild-type sporozoites. Our data show that sustainable protection against malaria associates with distinct intra-hepatic immune responses characterized by strong IFNγ producing CD8+ memory T cells.

  18. Survival and antigenic profile of irradiated malarial sporozoites in infected liver cells

    International Nuclear Information System (INIS)

    Suhrbier, A.; Winger, L.A.; Castellano, E.; Sinden, R.E.

    1990-01-01

    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 antigens into the cytoplasm of the infected host cells. Increasing radiation dosage, which has previously been shown to reduce the ability of irradiated sporozoites to protect animals, correlated with reduced de novo antigen synthesis by EE parasites derived from irradiated sporozoites

  19. Plasmodium berghei Δp52&p36 parasites develop independent of a parasitophorous vacuole membrane in Huh-7 liver cells.

    Science.gov (United States)

    Ploemen, Ivo H J; Croes, Huib J; van Gemert, Geert-Jan J; Wijers-Rouw, Mietske; Hermsen, Cornelus C; Sauerwein, Robert W

    2012-01-01

    The proteins P52 and P36 are expressed in the sporozoite stage of the murine malaria parasite Plasmodium berghei. Δp52&p36 sporozoites lacking expression of both proteins are severely compromised in their capability to develop into liver stage parasites and abort development soon after invasion; presumably due to the absence of a parasitophorous vacuole membrane (PVM). However, a small proportion of P. berghei Δp52&p36 parasites is capable to fully mature in hepatocytes causing breakthrough blood stage infections. We have studied the maturation of replicating Δp52&p36 parasites in cultured Huh-7 hepatocytes. Approximately 50% of Δp52&p36 parasites developed inside the nucleus of the hepatocyte but did not complete maturation and failed to produce merosomes. In contrast cytosolic Δp52&p36 parasites were able to fully mature and produced infectious merozoites. These Δp52&p36 parasites developed into mature schizonts in the absence of an apparent parasitophorous vacuole membrane as shown by immunofluorescence and electron microscopy. Merozoites derived from these maturing Δp52&p36 liver stages were infectious for C57BL/6 mice.

  20. Selection of drug resistant mutants from random library of Plasmodium falciparum dihydrofolate reductase in Plasmodium berghei model

    Directory of Open Access Journals (Sweden)

    Yuthavong Yongyuth

    2011-05-01

    Full Text Available Abstract Background The prevalence of drug resistance amongst the human malaria Plasmodium species has most commonly been associated with genomic mutation within the parasites. This phenomenon necessitates evolutionary predictive studies of possible resistance mutations, which may occur when a new drug is introduced. Therefore, identification of possible new Plasmodium falciparum dihydrofolate reductase (PfDHFR mutants that confer resistance to antifolate drugs is essential in the process of antifolate anti-malarial drug development. Methods A system to identify mutations in Pfdhfr gene that confer antifolate drug resistance using an animal Plasmodium parasite model was developed. By using error-prone PCR and Plasmodium transfection technologies, libraries of Pfdhfr mutant were generated and then episomally transfected to Plasmodium berghei parasites, from which pyrimethamine-resistant PfDHFR mutants were selected. Results The principal mutation found from this experiment was S108N, coincident with the first pyrimethamine-resistance mutation isolated from the field. A transgenic P. berghei, in which endogenous Pbdhfr allele was replaced with the mutant PfdhfrS108N, was generated and confirmed to have normal growth rate comparing to parental non-transgenic parasite and also confer resistance to pyrimethamine. Conclusion This study demonstrated the power of the transgenic P. berghei system to predict drug-resistant Pfdhfr mutations in an in vivo parasite/host setting. The system could be utilized for identification of possible novel drug-resistant mutants that could arise against new antifolate compounds and for prediction the evolution of resistance mutations.

  1. Multidrug ATP-binding cassette transporters are essential for hepatic development of Plasmodium sporozoites.

    Science.gov (United States)

    Rijpma, Sanna R; van der Velden, Maarten; González-Pons, Maria; Annoura, Takeshi; van Schaijk, Ben C L; van Gemert, Geert-Jan; van den Heuvel, Jeroen J M W; Ramesar, Jai; Chevalley-Maurel, Severine; Ploemen, Ivo H; Khan, Shahid M; Franetich, Jean-Francois; Mazier, Dominique; de Wilt, Johannes H W; Serrano, Adelfa E; Russel, Frans G M; Janse, Chris J; Sauerwein, Robert W; Koenderink, Jan B; Franke-Fayard, Blandine M

    2016-03-01

    Multidrug resistance-associated proteins (MRPs) belong to the C-family of ATP-binding cassette (ABC) transport proteins and are known to transport a variety of physiologically important compounds and to be involved in the extrusion of pharmaceuticals. Rodent malaria parasites encode a single ABC transporter subfamily C protein, whereas human parasites encode two: MRP1 and MRP2. Although associated with drug resistance, their biological function and substrates remain unknown. To elucidate the role of MRP throughout the parasite life cycle, Plasmodium berghei and Plasmodium falciparum mutants lacking MRP expression were generated. P. berghei mutants lacking expression of the single MRP as well as P. falciparum mutants lacking MRP1, MRP2 or both proteins have similar blood stage growth kinetics and drug-sensitivity profiles as wild type parasites. We show that MRP1-deficient parasites readily invade primary human hepatocytes and develop into mature liver stages. In contrast, both P. falciparum MRP2-deficient parasites and P. berghei mutants lacking MRP protein expression abort in mid to late liver stage development, failing to produce mature liver stages. The combined P. berghei and P. falciparum data are the first demonstration of a critical role of an ABC transporter during Plasmodium liver stage development. © 2015 John Wiley & Sons Ltd.

  2. Variant-specific immunity to Plasmodium berghei in pregnant mice

    DEFF Research Database (Denmark)

    Megnekou, Rosette; Hviid, Lars; Staalsoe, Trine

    2009-01-01

    for recrudescence-type IEs are related to the protection of pregnant mice from maternal anemia, low birth weight, and decreased litter size. We conclude that the model replicates many of the key parasitological and immunological features of PAM, although the P. berghei genome does not encode proteins homologous...... to the P. falciparum erythrocyte membrane protein 1 adhesins, which are of key importance in P. falciparum malaria. The study of P. berghei malaria in pregnant, immune mice can be used to gain significant new insights regarding malaria pathogenesis and immunity in general and regarding PAM in particular....

  3. Transition of Plasmodium sporozoites into liver stage-like forms is regulated by the RNA binding protein Pumilio

    KAUST Repository

    Gomes-Santos, Carina S. S.; Braks, Joanna; Prudê ncio, Miguel; Carret, Cé line; Gomes, Ana Rita; Pain, Arnab; Feltwell, Theresa; Khan, Shahid; Waters, Andrew; Janse, Chris; Mair, Gunnar R.; Mota, Maria M.

    2011-01-01

    -associated environmental cues. Puf2- sporozoites exhibit genome-wide transcriptional changes that result in loss of gliding motility, cell traversal ability and reduction in infectivity, and, moreover, trigger metamorphosis typical of early Plasmodium intra-hepatic

  4. Exacerbation of autoimmune neuro-inflammation in mice cured from blood-stage Plasmodium berghei infection.

    Directory of Open Access Journals (Sweden)

    Rodolfo Thomé

    Full Text Available The thymus plays an important role shaping the T cell repertoire in the periphery, partly, through the elimination of inflammatory auto-reactive cells. It has been shown that, during Plasmodium berghei infection, the thymus is rendered atrophic by the premature egress of CD4+CD8+ double-positive (DP T cells to the periphery. To investigate whether autoimmune diseases are affected after Plasmodium berghei NK65 infection, we immunized C57BL/6 mice, which was previously infected with P. berghei NK65 and treated with chloroquine (CQ, with MOG35-55 peptide and the clinical course of Experimental Autoimmune Encephalomyelitis (EAE was evaluated. Our results showed that NK65+CQ+EAE mice developed a more severe disease than control EAE mice. The same pattern of disease severity was observed in MOG35-55-immunized mice after adoptive transfer of P. berghei-elicited splenic DP-T cells. The higher frequency of IL-17+- and IFN-γ+-producing DP lymphocytes in the Central Nervous System of these mice suggests that immature lymphocytes contribute to disease worsening. To our knowledge, this is the first study to integrate the possible relationship between malaria and multiple sclerosis through the contribution of the thymus. Notwithstanding, further studies must be conducted to assert the relevance of malaria-induced thymic atrophy in the susceptibility and clinical course of other inflammatory autoimmune diseases.

  5. Expression profiling of Plasmodium berghei HSP70 genes for generation of bright red fluorescent parasites.

    Directory of Open Access Journals (Sweden)

    Marion Hliscs

    Full Text Available Live cell imaging of recombinant malarial parasites encoding fluorescent probes provides critical insights into parasite-host interactions and life cycle progression. In this study, we generated a red fluorescent line of the murine malarial parasite Plasmodium berghei. To allow constitutive and abundant expression of the mCherry protein we profiled expression of all members of the P. berghei heat shock protein 70 (HSP70 family. We identified PbHSP70/1, an invariant ortholog of Plasmodium falciparum HSP70-1, as the protein with the highest expression levels during Plasmodium blood, mosquito, and liver infection. Stable allelic insertion of a mCherry expression cassette into the PbHsp70/1 locus created constitutive red fluorescent P. berghei lines, termed Pbred. We show that these parasites can be used for live imaging of infected host cells and organs, including hepatocytes, erythrocytes, and whole Anopheles mosquitoes. Quantification of the fluorescence intensity of several Pbred parasite stages revealed significantly enhanced signal intensities in comparison to GFP expressed under the control of the constitutive EF1alpha promoter. We propose that systematic transcript profiling permits generation of reporter parasites, such as the Pbred lines described herein.

  6. A T-cell response to a liver-stage Plasmodium antigen is not boosted by repeated sporozoite immunizations

    Science.gov (United States)

    Murphy, Sean C.; Kas, Arnold; Stone, Brad C.; Bevan, Michael J.

    2013-01-01

    Development of an antimalarial subunit vaccine inducing protective cytotoxic T lymphocyte (CTL)-mediated immunity could pave the way for malaria eradication. Experimental immunization with sporozoites induces this type of protective response, but the extremely large number of proteins expressed by Plasmodium parasites has so far prohibited the identification of sufficient discrete T-cell antigens to develop subunit vaccines that produce sterile immunity. Here, using mice singly immunized with Plasmodium yoelii sporozoites and high-throughput screening, we identified a unique CTL response against the parasite ribosomal L3 protein. Unlike CTL responses to the circumsporozoite protein (CSP), the population of L3-specific CTLs was not expanded by multiple sporozoite immunizations. CSP is abundant in the sporozoite itself, whereas L3 expression does not increase until the liver stage. The response induced by a single immunization with sporozoites reduces the parasite load in the liver so greatly during subsequent immunizations that L3-specific responses are only generated during the primary exposure. Functional L3-specific CTLs can, however, be expanded by heterologous prime-boost regimens. Thus, although repeat sporozoite immunization expands responses to preformed antigens like CSP that are present in the sporozoite itself, this immunization strategy may not expand CTLs targeting parasite proteins that are synthesized later. Heterologous strategies may be needed to increase CTL responses across the entire spectrum of Plasmodium liver-stage proteins. PMID:23530242

  7. Impact of sex differences in brain response to infection with Plasmodium berghei.

    Science.gov (United States)

    Dkhil, Mohamed A; Al-Shaebi, Esam M; Lubbad, Mahmoud Y; Al-Quraishy, Saleh

    2016-01-01

    Malaria is considered to be one of the most prevalent diseases in the world. Severity of the disease between males and females is very important in clinical research areas. In this study, we investigated the impact of sex differences in brain response to infection with Plasmodium berghei. Male and female C57Bl/6 mice were infected with P. berghei-infected erythrocytes. The infection induced a significant change in weight loss in males (-7.2 % ± 0.5) than females (-4.9 % ± 0.6). The maximum parasitemia reached about 15 % at day 9 postinfection. Also, P. berghei infection caused histopathological changes in the brain of mice. These changes were in the form of inflammation, hemorrhage, and structural changes in Purkinje cells. In addition, P. berghei was able to induce a marked oxidative damage in mice brain. The infection induced a significant increase in male brain glutathione than females while the brain catalase level was significantly increased in infected females than infected males. Moreover, the change in brain neurotransmitters, dopamine, epinephrine, norepinephrine, and serotonin, was more in infected males than infected females. At the molecular level, P. berghei was able to induce upregulations of Adam23, Cabp1, Cacnb4, Glrb, and Vdac3-mRNA in the brain of mice. These genes were significantly upregulated in infected males than in infected females. In general, P. berghei could induce structural, biochemical, and molecular alterations in mice brain. Severity of these alterations was different according to sex of mice.

  8. Antiplasmodial activity of two medicinal plants against clinical isolates of Plasmodium falciparum and Plasmodium berghei infected mice.

    Science.gov (United States)

    Attemene, Serge David Dago; Beourou, Sylvain; Tuo, Karim; Gnondjui, Albert Alloh; Konate, Abibatou; Toure, Andre Offianan; Kati-Coulibaly, Seraphin; Djaman, Joseph Alico

    2018-03-01

    Malaria is an infectious and deadly parasitic disease, associated with fever, anaemia and other ailments. Unfortunately the upsurge of plasmodium multidrug resistant constrained researchers to look for new effective drugs. Medicinal plants seem to be an unquenchable source of bioactive principles in the treatment of various diseases. The aim of this study was to assess the antiplasmodial activity of two Ivorian medicinal plants. The in vitro activity was evaluated against clinical isolates and Plasmodium falciparum K1 multidrug resistant strain using the fluorescence based SYBR green I assay. The in vivo bioassay was carried out using the classical 4 day suppressive and curative tests on Plasmodium berghei infected mice. Results showed that the in vitro bioassay of both plant extracts were found to exhibit a promising and moderate antiparasitic effects on clinical isolates (5 µg/mL plant extracts need to be investigated.

  9. Erythrocyte remodeling in Plasmodium berghei infection: the contribution of SEP family members.

    Science.gov (United States)

    Currà, Chiara; Pace, Tomasino; Franke-Fayard, Blandine M D; Picci, Leonardo; Bertuccini, Lucia; Ponzi, Marta

    2012-03-01

    The malaria parasite Plasmodium largely modifies the infected erythrocyte through the export of proteins to multiple sites within the host cell. This remodeling is crucial for pathology and translocation of virulence factors to the erythrocyte surface. In this study, we investigated localization and export of small exported proteins/early transcribed membrane proteins (SEP/ETRAMPs), conserved within Plasmodium genus. This protein family is characterized by a predicted signal peptide, a short lysine-rich stretch, an internal transmembrane domain and a highly charged C-terminal region of variable length. We show here that members of the rodent Plasmodium berghei family are components of the parasitophorous vacuole membrane (PVM), which surrounds the parasite throughout the erythrocytic cycle. During P. berghei development, vesicle-like structures containing these proteins detach from the PVM en route to the host cytosol. These SEP-containing vesicles remain associated with the infected erythrocyte ghosts most probably anchored to the membrane skeleton. Transgenic lines expressing the green fluorescent protein appended to different portions of sep-coding region allowed us to define motifs required for protein export. The highly charged terminal region appears to be involved in protein-protein interactions. © 2011 John Wiley & Sons A/S.

  10. Implications of Glutathione Levels in the Plasmodium berghei Response to Chloroquine and Artemisinin.

    Directory of Open Access Journals (Sweden)

    Joel Vega-Rodríguez

    Full Text Available Malaria is one of the most devastating parasitic diseases worldwide. Plasmodium drug resistance remains a major challenge to malaria control and has led to the re-emergence of the disease. Chloroquine (CQ and artemisinin (ART are thought to exert their anti-malarial activity inducing cytotoxicity in the parasite by blocking heme degradation (for CQ and increasing oxidative stress. Besides the contribution of the CQ resistance transporter (PfCRT and the multidrug resistant gene (pfmdr, CQ resistance has also been associated with increased parasite glutathione (GSH levels. ART resistance was recently shown to be associated with mutations in the K13-propeller protein. To analyze the role of GSH levels in CQ and ART resistance, we generated transgenic Plasmodium berghei parasites either deficient in or overexpressing the gamma-glutamylcysteine synthetase gene (pbggcs encoding the rate-limiting enzyme in GSH biosynthesis. These lines produce either lower (pbggcs-ko or higher (pbggcs-oe levels of GSH than wild type parasites. In addition, GSH levels were determined in P. berghei parasites resistant to CQ and mefloquine (MQ. Increased GSH levels were detected in both, CQ and MQ resistant parasites, when compared to the parental sensitive clone. Sensitivity to CQ and ART remained unaltered in both pgggcs-ko and pbggcs-oe parasites when tested in a 4 days drug suppressive assay. However, recrudescence assays after the parasites have been exposed to a sub-lethal dose of ART showed that parasites with low levels of GSH are more sensitive to ART treatment. These results suggest that GSH levels influence Plasmodium berghei response to ART treatment.

  11. Antiplasmodial activity of Xanthium strumarium against Plasmodium berghei-infected BALB/c mice.

    Science.gov (United States)

    Chandel, Sanjeev; Bagai, Upma; Vashishat, Nisha

    2012-03-01

    The present work was undertaken to evaluate the antiplasmodial activity of ethanolic leaves extract of traditional medicinal plant Xanthium strumarium in Plasmodium berghei-infected BALB/c mice along with phytochemical screening and acute toxicity test to support its traditional medicinal use as a malaria remedy. The ethanolic leaves extract of X. strumarium (ELEXS) 150, 250, 350 and 500 mg/kg/day demonstrated dose-dependent chemosuppression during early and established infection long with significant (p strumarium as malarial remedy and indicate the potential of plant for active antiplasmodial components.

  12. Effects of testosterone on blood leukocytes in plasmodium berghei-infected mice.

    Science.gov (United States)

    Kamis, A B; Ibrahim, J B

    1989-01-01

    Gonadectomized male mice aged 5 weeks were given 5 mg testosterone propionate daily for 14 days. The treatment significantly decreased the number of blood leukocytes. The number of all individual types of leukocytes except basophils in vehicle-treated gonadectomized mice was increased. Testosterone-treated mice consistently had a lower number of leukocytes after being infected with Plasmodium berghei than did vehicle-treated mice. The results suggest that testosterone suppresses the production of leukocytes and that testosterone-treated mice become more susceptible to parasite infection.

  13. Pengaruh Pemberian Vitamin A terhadap Penurunan Parasitemia Mencit Strain Swiss yang diinfeksi Plasmodium berghei

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    Umi Isnaeni

    2012-09-01

    Full Text Available Vitamin A merupakan vitamin yang berperan sebagai imunostimulan. Penelitian ini bertujuan untuk mengetahui apakah pemberian vitamin A dapat menurunkan parasitemia Plasmodium berghei pada mencit strain Swiss. Penelitian ini menggunakan 24 ekor mencit strain Swiss jantan berumur 6-8 minggu dengan berat badan 20-30 gram/ekor. Penelitian dilaksanakan secara eksperimental dengan menggunakan time series design. Dalam penelitian ini dilakukan perlakuan berupa pemberian vitamin A dengan 3 variasi dosis yaitu 0 IU/g BB, 35 IU/g BB dan 70 IU/g BB serta kelompok kontrol negatif dengan masing- masing kelompok terdiri dari 6 ekor mencit. Vitamin A diberikan 1 jam sebelum penginfeksian dan mencit dirawat sampai mencit pada kelompok kontrol negatif mati. Sediaan apus darah tipis dibuat 2 hari sekali dan parasitemia dihitung dengan pengecatan Giemsa. Data parasitemia dianalisis dengan ANOVA.Untuk hasil yang signifikan maka dilanjutkan dengan uji lanjut Post hoc pada taraf kesalahan 1%. Hasil uji ANOVA untuk kelompok perlakuan B, C dan D diperoleh nilai p <0,001 pada masing-masing kelompok perlakuan. Hal tersebut menyatakan bahwa adanya perbedaan yang signifikan pada perlakuan yang diberikan. Begitu juga untuk uji lanjut Post hoc yang telah dilakukan diperoleh nilai p < 0,001. Dapat disimpulkan bahwa pemberian vitamin A berpengaruh terhadap penurunan parasitemia Plasmodium berghei pada mencit strain Swiss.Vitamin A is a vitamin that acts as an immunostimulant. This research aims to determine whether the administration of vitamin A can reduce parasitaemia of Plasmodium berghei in Switzerland strain mice. This research used 24 mice Switzerland strain mice 6-8 weeks old weighing 20-30 grams/tail. Research conducted experimentally by using time series design. In this research, the provision of vitamin A treatment with 3 doses of variation is 0 IU/g BW, 35 IU/g BW and 70 IU/g BW as well as the negative control group, with each group consisting of 6 mice. Vitamin A

  14. Improved negative selection protocol for Plasmodium berghei in the rodent malarial model

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    Orr Rachael Y

    2012-03-01

    Full Text Available Abstract An improved methodology is presented here for transgenic Plasmodium berghei lines that express the negative selectable marker yFCU (a bifunctional protein that combines yeast cytosine deaminase and uridyl phosphoribosyl transferase (UPRT and substitutes delivery of selection drug 5-fluorocytosine (5FC by intraperitoneal injection for administration via the drinking water of the mice. The improved methodology is shown to be as effective, less labour-intensive, reduces animal handling and animal numbers required for successful selection thereby contributing to two of the "three Rs" of animal experimentation, namely refinement and reduction.

  15. [Chemical and biological evaluation of the effect of plant extracts against Plasmodium berghei].

    Science.gov (United States)

    Castro, O; Barrios, M; Chinchilla, M; Guerrero, O

    1996-08-01

    Extracts from thirteen species of plants were evaluated by "in vivo" antimalarial test against plasmodium berghei effects. Significant activities were observed in the ethyl acetate and aqueous extracts, elaborated of Cedrela tonduzii leaves, Trichilia havanensis and Trichilia americana barks, Neurolaena lobata and Gliricidia sepium leaves and Duranta repens fruits. Compounds identified include flavanoids, coumarins, mellilotic acid and iridoids which some kind of biodynamic activity has previously been reported. The flavone quercetin 1 purified from C. tonduzii gave strong antimalarial activity, however, its respective glucosides (quercetin 3-glucoside 2 y robinine 7) showed little significant activity.

  16. Transmission blocking effects of neem (Azadirachta indica) seed kernel limonoids on Plasmodium berghei early sporogonic development.

    Science.gov (United States)

    Tapanelli, Sofia; Chianese, Giuseppina; Lucantoni, Leonardo; Yerbanga, Rakiswendé Serge; Habluetzel, Annette; Taglialatela-Scafati, Orazio

    2016-10-01

    Azadirachta indica, known as neem tree and traditionally called "nature's drug store" makes part of several African pharmacopeias and is widely used for the preparation of homemade remedies and commercial preparations against various illnesses, including malaria. Employing a bio-guided fractionation approach, molecules obtained from A. indica ripe and green fruit kernels were tested for activity against early sporogonic stages of Plasmodium berghei, the parasite stages that develop in the mosquito mid gut after an infective blood meal. The limonoid deacetylnimbin (3) was identified as one the most active compounds of the extract, with a considerably higher activity compared to that of the close analogue nimbin (2). Pure deacetylnimbin (3) appeared to interfere with transmissible Plasmodium stages at a similar potency as azadirachtin A. Considering its higher thermal and chemical stability, deacetylnimbin could represent a suitable alternative to azadirachtin A for the preparation of transmission blocking antimalarials. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Cytochrome c and c1 heme lyases are essential in Plasmodium berghei.

    Science.gov (United States)

    Posayapisit, Navaporn; Songsungthong, Warangkhana; Koonyosying, Pongpisid; Falade, Mofolusho O; Uthaipibull, Chairat; Yuthavong, Yongyuth; Shaw, Philip J; Kamchonwongpaisan, Sumalee

    Malaria parasites possess a de novo heme synthetic pathway. Interestingly, this pathway is dispensable during the blood stages of development in mammalian hosts. The assembly of the two most important hemeproteins, cytochromes c and c1, is mediated by cytochrome heme lyase enzymes. Plasmodium spp. possess two cytochrome heme lyases encoded by separate genes. Given the redundancy of heme synthesis, we sought to determine if heme lyase function also exhibits redundancy. To answer this question, we performed gene knockout experiments. We found that the PBANKA_143950 and PBANKA_0602600 Plasmodium berghei genes encoding cytochrome c (Pbcchl) and cytochrome c1 (Pbcc 1 hl) heme lyases, respectively, can only be disrupted when a complementary gene is present. In contrast, four genes in the de novo heme synthesis pathway can be disrupted without complementation. This work provides evidence that Pbcchl and Pbcc 1 hl are both essential and thus may be antimalarial targets. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Transition of Plasmodium sporozoites into liver stage-like forms is regulated by the RNA binding protein Pumilio

    KAUST Repository

    Gomes-Santos, Carina S. S.

    2011-05-19

    Many eukaryotic developmental and cell fate decisions that are effected post-transcriptionally involve RNA binding proteins as regulators of translation of key mRNAs. In malaria parasites (Plasmodium spp.), the development of round, non-motile and replicating exo-erythrocytic liver stage forms from slender, motile and cell-cycle arrested sporozoites is believed to depend on environmental changes experienced during the transmission of the parasite from the mosquito vector to the vertebrate host. Here we identify a Plasmodium member of the RNA binding protein family PUF as a key regulator of this transformation. In the absence of Pumilio-2 (Puf2) sporozoites initiate EEF development inside mosquito salivary glands independently of the normal transmission-associated environmental cues. Puf2- sporozoites exhibit genome-wide transcriptional changes that result in loss of gliding motility, cell traversal ability and reduction in infectivity, and, moreover, trigger metamorphosis typical of early Plasmodium intra-hepatic development. These data demonstrate that Puf2 is a key player in regulating sporozoite developmental control, and imply that transformation of salivary gland-resident sporozoites into liver stage-like parasites is regulated by a post-transcriptional mechanism. 2011 Gomes-Santos et al.

  19. Expression of human CD81 differently affects host cell susceptibility to malaria sporozoites depending on the Plasmodium species.

    NARCIS (Netherlands)

    Silvie, O.; Greco, C.; Franetich, J.F.; Dubart-Kupperschmitt, A.; Hannoun, L.; Gemert, G.J.A. van; Sauerwein, R.W.; Levy, S.; Boucheix, C.; Rubinstein, E.; Mazier, D.

    2006-01-01

    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

  20. Temperature shift and host cell contact up-regulate sporozoite expression of Plasmodium falciparum genes involved in hepatocyte infection.

    Directory of Open Access Journals (Sweden)

    Anthony Siau

    Full Text Available Plasmodium sporozoites are deposited in the skin by Anopheles mosquitoes. They then find their way to the liver, where they specifically invade hepatocytes in which they develop to yield merozoites infective to red blood cells. Relatively little is known of the molecular interactions during these initial obligatory phases of the infection. Recent data suggested that many of the inoculated sporozoites invade hepatocytes an hour or more after the infective bite. We hypothesised that this pre-invasive period in the mammalian host prepares sporozoites for successful hepatocyte infection. Therefore, the genes whose expression becomes modified prior to hepatocyte invasion would be those likely to code for proteins implicated in the subsequent events of invasion and development. We have used P. falciparum sporozoites and their natural host cells, primary human hepatocytes, in in vitro co-culture system as a model for the pre-invasive period. We first established that under co-culture conditions, sporozoites maintain infectivity for an hour or more, in contrast to a drastic loss in infectivity when hepatocytes were not included. Thus, a differential transcriptome of salivary gland sporozoites versus sporozoites co-cultured with hepatocytes was established using a pan-genomic P. falciparum microarray. The expression of 532 genes was found to have been up-regulated following co-culture. A fifth of these genes had no orthologues in the genomes of Plasmodium species used in rodent models of malaria. Quantitative RT-PCR analysis of a selection of 21 genes confirmed the reliability of the microarray data. Time-course analysis further indicated two patterns of up-regulation following sporozoite co-culture, one transient and the other sustained, suggesting roles in hepatocyte invasion and liver stage development, respectively. This was supported by functional studies of four hitherto uncharacterized proteins of which two were shown to be sporozoite surface

  1. Development of a metabolically active, non-replicating sporozoite vaccine to prevent Plasmodium falciparum malaria.

    Science.gov (United States)

    Hoffman, Stephen L; Billingsley, Peter F; James, Eric; Richman, Adam; Loyevsky, Mark; Li, Tao; Chakravarty, Sumana; Gunasekera, Anusha; Chattopadhyay, Rana; Li, Minglin; Stafford, Richard; Ahumada, Adriana; Epstein, Judith E; Sedegah, Martha; Reyes, Sharina; Richie, Thomas L; Lyke, Kirsten E; Edelman, Robert; Laurens, Matthew B; Plowe, Christopher V; Sim, B Kim Lee

    2010-01-01

    Immunization of volunteers by the bite of mosquitoes carrying radiation-attenuated Plasmodium falciparum sporozoites protects greater than 90% of such volunteers against malaria, if adequate numbers of immunizing biting sessions and sporozoite-infected mosquitoes are used. Nonetheless, until recently it was considered impossible to develop, license and commercialize a live, whole parasite P. falciparum sporozoite (PfSPZ) vaccine. In 2003 Sanaria scientists reappraised the potential impact of a metabolically active, non-replicating PfSPZ vaccine, and outlined the challenges to producing such a vaccine. Six years later, significant progress has been made in overcoming these challenges. This progress has enabled the manufacture and release of multiple clinical lots of a 1(st) generation metabolically active, non-replicating PfSPZ vaccine, the Sanaria PfSPZ Vaccine, submission of a successful Investigational New Drug application to the US Food and Drug Administration, and initiation of safety, immunogenicity and protective efficacy studies in volunteers in MD, US. Efforts are now focused on how best to achieve submission of a successful Biologics License Application and introduce the vaccine to the primary target population of African children in the shortest possible period of time. This will require implementation of a systematic, efficient clinical development plan. Short term challenges include optimizing the (1) efficiency and scale up of the manufacturing process and quality control assays, (2) dosage regimen and method of administration, (3) potency of the vaccine, and (4) logistics of delivering the vaccine to those who need it most, and finalizing the methods for vaccine stabilization and attenuation. A medium term goal is to design and build a facility for manufacturing highly potent and stable vaccine for pivotal Phase 3 studies and commercial launch.

  2. Mechanisms of invasion from sporozoite and merozoíto of Plasmodium

    Directory of Open Access Journals (Sweden)

    Lilian M. Spencer

    2016-05-01

    Full Text Available Malaria or paludismo is caused in humans by four species of Plasmodium belonging to phylum Apicomplexa: ovale, malaria, vivax and falciparum, being the last, the responsible of the clinical complication and death in the vertebrate host. Plasmodium parasite possess a specialized secretory organelles called rhoptries, micronemes and dense granules that facilitate invasion of host cells. The sporozoite stage of Plasmodium travels through the different cells of vertebrate host until it reaches the hepatocyte and have been form the parasitophorous vacuole. The infected hepatocytes rupture, results in the releasing thousands of daughter merozoites that invade the erythrocytes with the formation of parasitophorous vacuole too. Several researchers suggest the gliding motility mechanism as the responsible of hepatocyte invasion. While, which the erythrocyte invasion process has been described as the result of tree steps: first contact, re-orientation and invasion. In this review the surface proteins of merozoites and esporozoites are pointed out as the most important factors for the molecular invasion mechanisms until the elaboration of the parasitophorous vacuole. These proteins that take part in these mechanisms are the possible candidates in the design of an anti-malaria vaccine.

  3. Germinal center architecture disturbance during Plasmodium berghei ANKA infection in CBA mice

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    Pelajo-Machado Marcelo

    2007-05-01

    Full Text Available Abstract Background Immune responses to malaria blood stage infection are in general defective, with the need for long-term exposure to the parasite to achieve immunity, and with the development of immunopathology states such as cerebral malaria in many cases. One of the potential reasons for the difficulty in developing protective immunity is the poor development of memory responses. In this paper, the potential association of cellular reactivity in lymphoid organs (spleen, lymph nodes and Peyer's patches with immunity and pathology was evaluated during Plasmodium berghei ANKA infection in CBA mice. Methods CBA mice were infected with 1 × 106 P. berghei ANKA-parasitized erythrocytes and killed on days 3, 6–8 and 10 of infection. The spleen, lymph nodes and Peyer's patches were collected, fixed in Carson's formalin, cut in 5 μm sections, mounted in glass slides, stained with Lennert's Giemsa and haematoxylin-eosin and analysed with bright-field microscopy. Results Early (day 3 strong activation of T cells in secondary lymphoid organs was observed and, on days 6–8 of infection, there was overwhelming activation of B cells, with loss of conventional germinal center architecture, intense centroblast activation, proliferation and apoptosis but little differentiation to centrocytes. In the spleen, the marginal zone disappeared and the limits between the disorganized germinal center and the red pulp were blurred. Intense plasmacytogenesis was observed in the T cell zone. Conclusion The observed alterations, especially the germinal center architecture disturbance (GCAD with poor centrocyte differentiation, suggest that B cell responses during P. berghei ANKA infection in mice are defective, with potential impact on B cell memory responses.

  4. Examining the Reticulocyte Preference of Two Plasmodium berghei Strains during Blood-Stage Malaria Infection

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    Neha Thakre

    2018-02-01

    Full Text Available The blood-stage of the Plasmodium parasite is one of the key phases within its life cycle that influences disease progression during a malaria infection. The efficiency of the parasite in infecting red blood cells (RBC determines parasite load and parasite-induced hemolysis that is responsible for the development of anemia and potentially drives severe disease progression. However, the molecular factors defining the infectivity of Plasmodium parasites have not been completely identified so far. Using the Plasmodium berghei mouse model for malaria, we characterized and compared the blood-stage infection dynamics of PbANKA WT and a mutant parasite strain lacking a novel Plasmodium antigen, PbmaLS_05, that is well conserved in both human and animal Plasmodium parasite strains. Infection of mice with parasites lacking PbmaLS_05 leads to lower parasitemia levels and less severe disease progression in contrast to mice infected with the wildtype PbANKA strain. To specifically determine the effect of deleting PbmaLS_05 on parasite infectivity we developed a mathematical model describing erythropoiesis and malarial infection of RBC. By applying our model to experimental data studying infection dynamics under normal and drug-induced altered erythropoietic conditions, we found that both PbANKA and PbmaLS_05 (- parasite strains differed in their infectivity potential during the early intra-erythrocytic stage of infection. Parasites lacking PbmaLS_05 showed a decreased ability to infect RBC, and immature reticulocytes in particular that are usually a preferential target of the parasite. These altered infectivity characteristics limit parasite burden and affect disease progression. Our integrative analysis combining mathematical models and experimental data suggests that deletion of PbmaLS_05 affects productive infection of reticulocytes, which makes this antigen a useful target to analyze the actual processes relating RBC preferences to the development of

  5. Antihemolytic Activities of Green Tea, Safflower, and Mulberry Extracts during Plasmodium berghei Infection in Mice

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    Suthin Audomkasok

    2014-01-01

    Full Text Available Malaria-associated hemolysis is associated with mortality in adult patients. It has been speculated that oxidative stress and inflammation induced by malaria parasite are involved in its pathophysiology. Hence, we aimed to investigate the antihemolytic effect of green tea, safflower, and mulberry extracts against Plasmodium berghei infection. Aqueous crude extracts of these plants were prepared using hot water method and used for oral treatment in mice. Groups of ICR mice were infected with 6 × 106 infected red blood cells of P. berghei ANKA by intraperitoneal injection and given the extracts (500, 1500, and 3000 mg/kg twice a day for 4 consecutive days. To assess hemolysis, hematocrit levels were then evaluated. Malaria infection resulted in hemolysis. However, antihemolytic effects were observed in infected mice treated with these extracts at dose-dependent manners. In conclusion, aqueous crude extracts of green tea, safflower, and mulberry exerted antihemolysis induced by malaria infection. These plants may work as potential source in the development of variety of herbal formulations for malarial treatment.

  6. Excess Fibrin Deposits Decrease Fetal Weight of Pregnant Mice Infected by Plasmodium berghei

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    Desy Andari

    2014-05-01

    Full Text Available Low birth weight is commonly attributed to malaria in pregnancy, but the cellular and molecular mechanisms that underlie this poor birth outcome are incompletely understood. A universally described histopathological feature of placental malaria is excessive deposition of fibrin, the end-product of the coagulation cascade. This study was conducted to compare fibrin deposit in pregnant mice that infected by Plasmodium berghei (treatment group to the normal pregnant mice (control group and its association with fetal weight. This research is in vivo experimental laboratory study that used 18 pregnant Balb/c mice which divided to the control the group (8 mice and treatment group (9 mice infected by P.berghei. Placentas were staining with Haematoxylin-Eosin (HE for fibrin deposits examination whereas fetal weight was performed with Mettler analytical balance AE 50. Fetal weight of the treatment group was lower than those of the control group (t test, p=0,002. Fibrin deposits were increased in the treatment group (t test, p=0,005 and influenced weight of fetuses (Spearman r= -0,586, p= 0,014. Weights of fetuses are interfered by fibrin deposits during malaria infection.

  7. Antiplasmodial activity of methanolic extract of asparagus officinalis l. stem on plasmodium berghei infected mice

    International Nuclear Information System (INIS)

    Minari, J.B.; Adutuga, A.A.

    2016-01-01

    This study aims at investigating the antiplasmodial activity of methanolic extract of Asparagus officinalis L. stem on Plasmodium berghei infected mice. To investigate this, the mice were infected with P.berghei to cause malaria. The mice were simultaneously given oral doses (20, 40 and 60 mg/kg body weight) of methanolic extract of A. officinalis L. stem. The phytochemical constituents of the extract revealed the presence of alkaloids, phenolics, cardiac glycosides, flavonoids, terpenoid and steroid. The extract administered to the infected mice significantly suppressed the parasite. The extract also significantly (P<0.05) reduced the activities of serum aspatate aminotransferase (AST), alkaline phosphate (ALP), alanine aminotransferase (ALT). White blood corpuscles (WBC), red blood corpuscles (RBC), hemoglobin (HGB), packed cell volume (PCV), platelets (PLT) and the mean corpuscular hemoglobin concentration (MCHC) showed significant (P<0.05) increase after the administration of the extract while mean corpuscular volume (MCV) and the mean corpuscular hemoglobin (MCH) showed significant (P<0.05) reduction. Present findings suggests that the plant extract contains phytochemicals that have antiplasmodial and hepatoprotective properties. (author)

  8. Study of the antimalarial properties of hydroxyethylamine derivatives using green fluorescent protein transformed Plasmodium berghei

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    Mariana Conceição Souza

    2015-06-01

    Full Text Available A rapid decrease in parasitaemia remains the major goal for new antimalarial drugs and thus, in vivo models must provide precise results concerning parasitaemia modulation. Hydroxyethylamine comprise an important group of alkanolamine compounds that exhibit pharmacological properties as proteases inhibitors that has already been proposed as a new class of antimalarial drugs. Herein, it was tested the antimalarial property of new nine different hydroxyethylamine derivatives using the green fluorescent protein (GFP-expressing Plasmodium berghei strain. By comparing flow cytometry and microscopic analysis to evaluate parasitaemia recrudescence, it was observed that flow cytometry was a more sensitive methodology. The nine hydroxyethylamine derivatives were obtained by inserting one of the following radical in the para position: H, 4Cl, 4-Br, 4-F, 4-CH3, 4-OCH3, 4-NO2, 4-NH2 and 3-Br. The antimalarial test showed that the compound that received the methyl group (4-CH3 inhibited 70% of parasite growth. Our results suggest that GFP-transfected P. berghei is a useful tool to study the recrudescence of novel antimalarial drugs through parasitaemia examination by flow cytometry. Furthermore, it was demonstrated that the insertion of a methyl group at the para position of the sulfonamide ring appears to be critical for the antimalarial activity of this class of compounds.

  9. Plasmodium berghei: immunosuppression of the cell-mediated immune response induced by nonviable antigenic preparations

    International Nuclear Information System (INIS)

    Gross, A.; Frankenburg, S.

    1989-01-01

    In this work, plasmodial antigens were examined for their ability to suppress the cellular immune response during lethal Plasmodium berghei infection. Splenic enlargement and the number and function of white spleen cells were assessed after injection of normal mice with irradiated parasitized erythrocytes (IPE) or with parasitized erythrocytes (PE) membranes. Both IPE and PE membranes caused splenomegaly and an increase in the number of splenic white cells with concurrent alteration of the relative proportions of T cells and macrophages. The percentage of T lymphocytes was fractionally diminished, but there was a marked increase in Lyt 2.2 positive (suppressor and cytotoxic) T subsets and in the number of splenic macrophage precursors. The pathological enlargement of the spleen was induced by various plasma membrane-derived antigens containing both proteins and carbohydrates. Splenocytes of mice injected with liposomes containing deoxycholate-treated PE or PE fractions showed both diminished interleukin 2 production and a decreased response to mitogen. It appears that some of the changes in the cellular immune response during P. berghei infection are a consequence of the massive provision of a wide spectrum of antigens, capable of suppressing the immune response. Thus, it may be appropriate to evaluate the possible negative effect of parasite epitopes that are candidates for vaccine

  10. Evaluation of the ex vivo antimalarial activity of organotin (IV) ethylphenyldithiocarbamate on erythrocytes infected with Plasmodium berghei NK 65.

    Science.gov (United States)

    Awang, Normah; Jumat, Hafizah; Ishak, Shafariatul Akmar; Kamaludin, Nurul Farahana

    2014-06-01

    Malaria is the most destructive and dangerous parasitic disease. The commonness of this disease is getting worse mainly due to the increasing resistance of Plasmodium falciparum against antimalarial drugs. Therefore, the search for new antimalarial drug is urgently needed. This study was carried out to evaluate the effects of dibutyltin (IV) ethylphenyldithiocarbamate (DBEP), diphenyltin (IV) ethylphenyldithiocarbamate (DPEP) and triphenyltin (IV) ethylphenyldithiocarbamate (TPEP) compounds as antimalarial agents. These compounds were evaluated against erythrocytes infected with Plasmodium berghei NK65 via ex vivo. Organotin (IV) ethylphenyldithiocarbamate, [R(n)Sn(C9H10NS2)(4-n)] with R = C4H9 and C6H5 for n = 2; R = C6H5 for n = 3 is chemically synthesised for its potential activities. pLDH assay was employed for determination of the concentration that inhibited 50% of the Plasmodium's activity (IC50) after 24 h treatment at concentration range of 10-0.0000001 mg mL(-1). Plasmodium berghei NK65 was cultured in vitro to determine the different morphology of trophozoite and schizont. Only DPEP and TPEP compounds have antimalarial activity towards P. berghei NK65 at IC50 0.094±0.011 and 0.892±0.088 mg mL(-1), respectively. The IC50 of DPEP and TPEP were lowest at 30% parasitemia with IC50 0.001±0.00009 and 0.0009±0.0001 mg mL(-1), respectively. In vitro culture showed that TPEP was effective towards P. berghei NK65 in trophozoite and schizont morphology with IC50 0.0001±0.00005 and 0.00009±0.00003 μg mL(-1), respectively. In conclusion, DPEP and TPEP have antimalarial effect on erythrocytes infected with P. berghei NK65 and have potential as antimalarial and schizonticidal agents.

  11. Effects of levamisole on experimental infections by Plasmodium berghei in mice

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    Enrique Melendez C.

    1987-12-01

    Full Text Available Levamisole (phenylimidothiazol, considered a strong immunostimulant, when administered to healthy Swiss mice did not cause a significant increase in -the weight of their thymus, liver and spleen, even though the drug was used at different times before removing such organs. High doses ofdrug used in the 4-day prophylactic scheme had no antimalarial effect. However, when given to malaria infected mice 24 hours before, at the same time, and 24 hours after the inoculation of a chloroquine-sensitive or a chloroquine-resistant strain of Plasmodium berghei small doses of the drug induced a somewhat decreased parasitemia, the dose of 1 mg/kg body weight before the inoculum being the best scheme. The mortality rates by malaria in the levamisole treated groups were also delayed although all mice finally died. The data suggest that levamisole may display a stimulant effect on the depressed immune response caused by malaria.

  12. Identification of a major rif transcript common to gametocytes and sporozoites of Plasmodium falciparum

    DEFF Research Database (Denmark)

    Wang, Christian W; Mwakalinga, Steven B; Sutherland, Colin J

    2010-01-01

    ABSTRACT: BACKGROUND: The Plasmodium falciparum parasite is transmitted in its sexual gametocyte stage from man to mosquito and as asexual sporozoites from mosquito to man. Developing gametocytes sequester preferentially in the bone marrow, but mature stage gametocytes are released...

  13. Antimalarial efficacy of Pongamia pinnata (L) Pierre against Plasmodium falciparum (3D7 strain) and Plasmodium berghei (ANKA).

    Science.gov (United States)

    Satish, P V V; Sunita, K

    2017-09-11

    The objective of the current study was to assess the in vitro antiplasmodial activities of leaf, bark, flower, and the root of Pongamia pinnata against chloroquine-sensitive Plasmodium falciparum (3D7 strain), cytotoxicity against Brine shrimp larvae and THP-1 cell line. For in vivo study, the plant extract which has shown potent in vitro antimalarial activity was tested against Plasmodium berghei (ANKA strain). The plant Pongamia pinnata was collected from the herbal garden of Acharya Nagarjuna University of Guntur district, Andhra Pradesh, India. Sequentially crude extracts of methanol (polar), chloroform (non-polar), hexane (non-polar), ethyl acetate (non-polar) and aqueous (polar) of dried leaves, bark, flowers and roots of Pongamia pinnata were prepared using Soxhlet apparatus. The extracts were screened for in vitro antimalarial activity against P. falciparum 3D7 strain. The cytotoxicity studies of crude extracts were conducted against Brine shrimp larvae and THP-1 cell line. Phytochemical analysis of the plant extracts was carried out by following the standard methods. The chemical injury to erythrocytes due to the plant extracts was checked. The in vivo study was conducted on P. berghei (ANKA) infected BALB/c albino mice by following 4-Day Suppressive, Repository, and Curative tests. Out of all the tested extracts, the methanol extract of the bark of Pongamia pinnata had shown an IC 50 value of 11.67 μg/mL with potent in vitro antimalarial activity and cytotoxicity evaluation revealed that this extract was not toxic against Brine shrimp and THP-1 cells. The injury to erythrocytes analysis had not shown any morphological alterations and damage to the erythrocytes after 48 h of incubation. Because methanolic bark extract of Pongamia pinnata has shown good antimalarial activity in vitro, it was also tested in vivo. So the extract had exhibited an excellent activity against P. berghei malaria parasite while decrement of parasite counts was moderately low and

  14. Targeting the Conserved Fusion Loop of HAP2 Inhibits the Transmission of Plasmodium berghei and falciparum

    Directory of Open Access Journals (Sweden)

    Fiona Angrisano

    2017-12-01

    Full Text Available Summary: Inhibiting transmission of Plasmodium is a central strategy in malarial eradication, and the biological process of gamete fusion during fertilization is a proven target for this approach. The lack of a structure or known molecular function of current anti-malarial vaccine targets has previously been a hindrance in the development of transmission-blocking vaccines. Structure/function studies have indicated that the conserved gamete membrane fusion protein HAP2 is a class II viral fusion protein. Here, we demonstrate that targeting a function-critical site of the fusion/cd loop with species-specific antibodies reduces Plasmodium berghei transmission in vivo by 58.9% and in vitro fertilization by up to 89.9%. A corresponding reduction in P. falciparum transmission (75.5%/36.4% reductions in intensity/prevalence is observed in complimentary field studies. These results emphasize conserved mechanisms of fusion in Apicomplexa, while highlighting an approach to design future anti-malarial transmission-blocking vaccines. : Angrisano et al. find that the HAP2 cd-loop can be targeted as an anti-malarial intervention, is immunogenic across multiple plasmodial species, can induce antibodies that specifically recognize the sexual stages of the parasitic life cycle, and can mediate transmission-blocking immunity in the lab and the field. Keywords: HAP2, malaria, transmission, fusion, vaccine

  15. The protective effect of Moringa oleifera leaf extract on liver damage in mice infected with Plasmodium berghei ANKA

    Directory of Open Access Journals (Sweden)

    Kittiyaporn Dondee

    2016-09-01

    Full Text Available Objective: To investigate the protective effect of Moringa oleifera leaf extract on liver damage in mice infected with Plasmodium berghei ANKA (P. berghei Methods: For extraction of Moringa oleifera (M. oleifera leaves, microwave with hot water method was used and acute toxicity study was then be done. Standard Peters’ test was carried out to test the efficacy of M. oleifera extract in vivo. The ICR mice were inoculated with 1 × 107 red blood cells infected with P. berghei strain by intraperitoneal injection. They were subsequently given with 100, 500 and 1000 mg/kg of this extract by intragastric route once a day for 4 consecutive days. Parasitemia was estimated using microscopy and levels of aspartate aminotransferase, alanine aminotransferase and albumin were also measured. Results: The M. oleifera leaf extract showed the protective activity on liver damage in mice infected with P. berghei in a dose-dependent fashion. It can be indicated by normal levels of aspartate aminotransferase, alanine aminotransferase and albumin in mice treated with extract. The 1000 mg/kg of extract was observed to present the highest activity. Interestingly, the dosedependent antimalarial activity was also found in the mice treated with extract. Conclusions: The M. oleifera leaf extract presented protective effect on liver damage in mice infected with P. berghei.

  16. Depletion of Plasmodium berghei Plasmoredoxin Reveals a Non-Essential Role for Life Cycle Progression of the Malaria Parasite

    OpenAIRE

    Buchholz, Kathrin; Rahlfs, Stefan; Schirmer, R. Heiner; Becker, Katja; Matuschewski, Kai

    2008-01-01

    Proliferation of the pathogenic Plasmodium asexual blood stages in host erythrocytes requires an exquisite capacity to protect the malaria parasite against oxidative stress. This function is achieved by a complex antioxidant defence system composed of redox-active proteins and low MW antioxidants. Here, we disrupted the P. berghei plasmoredoxin gene that encodes a parasite-specific 22 kDa member of the thioredoxin superfamily. The successful generation of plasmoredoxin knockout mutants in the...

  17. Glutathione-deficient Plasmodium berghei parasites exhibit growth delay and nuclear DNA damage.

    Science.gov (United States)

    Padín-Irizarry, Vivian; Colón-Lorenzo, Emilee E; Vega-Rodríguez, Joel; Castro, María Del R; González-Méndez, Ricardo; Ayala-Peña, Sylvette; Serrano, Adelfa E

    2016-06-01

    Plasmodium parasites are exposed to endogenous and exogenous oxidative stress during their complex life cycle. To minimize oxidative damage, the parasites use glutathione (GSH) and thioredoxin (Trx) as primary antioxidants. We previously showed that disruption of the Plasmodium berghei gamma-glutamylcysteine synthetase (pbggcs-ko) or the glutathione reductase (pbgr-ko) genes resulted in a significant reduction of GSH in intraerythrocytic stages, and a defect in growth in the pbggcs-ko parasites. In this report, time course experiments of parasite intraerythrocytic development and morphological studies showed a growth delay during the ring to schizont progression. Morphological analysis shows a significant reduction in size (diameter) of trophozoites and schizonts with increased number of cytoplasmic vacuoles in the pbggcs-ko parasites in comparison to the wild type (WT). Furthermore, the pbggcs-ko mutants exhibited an impaired response to oxidative stress and increased levels of nuclear DNA (nDNA) damage. Reduced GSH levels did not result in mitochondrial DNA (mtDNA) damage or protein carbonylations in neither pbggcs-ko nor pbgr-ko parasites. In addition, the pbggcs-ko mutant parasites showed an increase in mRNA expression of genes involved in oxidative stress detoxification and DNA synthesis, suggesting a potential compensatory mechanism to allow for parasite proliferation. These results reveal that low GSH levels affect parasite development through the impairment of oxidative stress reduction systems and damage to the nDNA. Our studies provide new insights into the role of the GSH antioxidant system in the intraerythrocytic development of Plasmodium parasites, with potential translation into novel pharmacological interventions. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  18. Minocycline prevents cerebral malaria, confers neuroprotection and increases survivability of mice during Plasmodium berghei ANKA infection.

    Science.gov (United States)

    Apoorv, Thittayil Suresh; Babu, Phanithi Prakash

    2017-02-01

    Cerebral malaria (CM) is a neurological complication arising due to Plasmodium falciparum or Plasmodium vivax infection. Minocycline, a semi-synthetic tetracycline, has been earlier reported to have a neuroprotective role in several neurodegenerative diseases. In this study, we investigated the effect of minocycline treatment on the survivability of mice during experimental cerebral malaria (ECM). The currently accepted mouse model, C57BL/6 mice infected with Plasmodium berghei ANKA, was used for the study. Infected mice were treated with an intra-peritoneal dose of minocycline hydrochloride, 45mg/kg daily for ten days that led to parasite clearance in blood, brain, liver and spleen on 7th day post-infection; and the mice survived until experiment ended (90days) without parasite recrudescence. Evans blue extravasation assay showed that blood-brain barrier integrity was maintained by minocycline. The tumor necrosis factor-alpha protein level and caspase activity, which is related to CM pathogenesis, was significantly reduced in the minocycline-treated group. Fluoro-Jade® C and hematoxylin-eosin staining of the brains of minocycline group revealed a decrease in degenerating neurons and absence of hemorrhages respectively. Minocycline treatment led to decrease in gene expressions of inflammatory mediators like interferon-gamma, CXCL10, CCL5, CCL2; receptors CXCR3 and CCR2; and hence decrease in T-cell-mediated cerebral inflammation. We also proved that this reduction in gene expressions is irrespective of the anti-parasitic property of minocycline. The distinct ability of minocycline to modulate gene expressions of CXCL10 and CXCR3 makes it effective than doxycycline, a tetracycline used as chemoprophylaxis. Our study shows that minocycline is highly effective in conferring neuroprotection during ECM. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Efeito de Momordica charantia I. Em camundongos infectados por Plasmodium berghei

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    Helene Mariko Ueno

    1996-10-01

    Full Text Available A Organização Mundial de Saúde (OMS citou a malãria como um dos principais problemas de saúde no Brasil e no terceiro mundo, onde 80% da população recorre à medicina tradicional (popular para sanar vários problemas de assistência médica primária. No que se refere à malária, seu tratamento e controle têm sido dificultados devido às cepas resistentes às drogas comumente utilizadas. Isso torna urgente a busca de novas drogas antimaláncas. Sabe-se que a população utiliza-se de diferentes plantas para o tratamento e cura de vários males, inclusive a malãria. Neste trabalho nos propusemos reavaliar o efeito de Momordica charantia L. (Cucurbitaceae sobre camundongos infectados por Plasmodium berghei. A planta foi testada sob a forma de extratos aquoso e etanólico, na dose de lOOOmg por kg cle peso coipóreo do camundongo, ministrado por via oral, por cinco dias consecutivos da infecção (2º ao 6º. O efeito foi avaliado em função da parasitemia e da sobrevida dos animais. Embora a população indique e utilize essa planta na malária humana, nos ensaios deste trabalho, nas condições do experimento, os extratos de M. charantia não apresentaram atividade satisfatória contra o P. berghei.

  20. Antimalarial efficacy of Albizia lebbeck (Leguminosae against Plasmodium falciparum in vitro & P. berghei in vivo

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    Shagun Kalia

    2015-01-01

    Full Text Available Background & objectives: Albizia lebbeck Benth. (Leguminosae has long been used in Indian traditional medicine. The current study was designed to test antimalarial activity of ethanolic bark extract of A. lebbeck (EBEAL. Methods: EBEAL was prepared by soxhlet extraction and subjected to phytochemical analysis. The extract was evaluated for its in vitro antimalarial activity against Plasmodium falciparum chloroquine (CQ sensitive (MRC2 and CQ resistant (RKL9 strains. Cytotoxicity (CC 50 of extract against HeLa cells was evaluated. Median lethal dose (LD 50 was determined to assess safety of EBEAL in BALB/c mice. Schizonticidal (100-1000 mg/kg and preventive (100-750 mg/kg activities of EBEAL were evaluated against P. berghei. Curative activity (100-750 mg/kg of extract was also evaluated. Results: Phytochemical screening revealed presence of alkaloids, flavonoids, phenols, saponins, terpenes and phytosterols. The extract exhibited IC 50 of 8.2 µg/ml (MRC2 and 5.1 µg/ml (RKL9. CC 50 of extract on HeLa cell line was calculated to be >1000 µg/ml. EBEAL showed selectivity indices (SI of >121.9 and >196.07 against MRC2 and RKL9 strains of P. falciparum, respectively. LD 50 of EBEAL was observed to be >5 g/kg. Dose-dependent chemosuppression was observed with significant ( p100 mg/kg. Significant (P<0.001 curative and repository activities were exhibited by 750 mg/kg concentration of extract on D7. Interpretation & conclusions: The present investigation reports antiplasmodial efficacy of EBEAL in vitro against P. falciparum as evident by high SI values. ED 50 of <100 mg/kg against P. berghei categorizes EBEAL as active antimalarial. Further studies need to be done to exploit its antiplasmodial activity further.

  1. Antimalarial efficacy of Albizia lebbeck (Leguminosae) against Plasmodium falciparum in vitro & P. berghei in vivo.

    Science.gov (United States)

    Kalia, Shagun; Walter, Neha Sylvia; Bagai, Upma

    2015-12-01

    Albizia lebbeck Benth. (Leguminosae) has long been used in Indian traditional medicine. The current study was designed to test antimalarial activity of ethanolic bark extract of A. lebbeck (EBEAL). EBEAL was prepared by soxhlet extraction and subjected to phytochemical analysis. The extract was evaluated for its in vitro antimalarial activity against Plasmodium falciparum chloroquine (CQ) sensitive (MRC2) and CQ resistant (RKL9) strains. Cytotoxicity (CC 50 ) of extract against HeLa cells was evaluated. Median lethal dose (LD 50 ) was determined to assess safety of EBEAL in BALB/c mice. Schizonticidal (100-1000 mg/kg) and preventive (100-750 mg/kg) activities of EBEAL were evaluated against P. berghei. Curative activity (100-750 mg/kg) of extract was also evaluated. Phytochemical screening revealed presence of alkaloids, flavonoids, phenols, saponins, terpenes and phytosterols. The extract exhibited IC 50 of 8.2 µg/ml (MRC2) and 5.1 µg/ml (RKL9). CC 50 of extract on HeLa cell line was calculated to be >1000 µg/ml. EBEAL showed selectivity indices (SI) of >121.9 and >196.07 against MRC2 and RKL9 strains of P. falciparum, respectively. LD 50 of EBEAL was observed to be >5 g/kg. Dose-dependent chemosuppression was observed with significant ( p50 >100 mg/kg. Significant (P50 mg/kg concentration of extract on D7. The present investigation reports antiplasmodial efficacy of EBEAL in vitro against P. falciparum as evident by high SI values. ED 50 of <100 mg/kg against P. berghei categorizes EBEAL as active antimalarial. Further studies need to be done to exploit its antiplasmodial activity further.

  2. Characterization of sporozoite surface antigens of Plasmodium falciparum, using monoclonal antibodies. Part of a coordinated programme on the preparation of irradiated vaccines against some human diseases

    International Nuclear Information System (INIS)

    Groot, M.

    1982-10-01

    Sporozoites are considered as a source of potential vaccine. Characterization of their antigens is therefore important and can be achieved by monoclonal antibodies. The purpose of this project is to study the production of monoclonal antibodies against sporozoites of P. falciparum. Various infections of mosquitoes were carried out during the period 1981-1982 to obtain antigens for the production of hybridomas. Hybridomas were produced from mice immunized through the bites of infected mosquitoes and by intravenous inoculation. The anti-sporozoite activity of the hybridomas was tested by an immunofluorescent antibody test using P. falciparum sporozoites as antigens. Positive immunofluorescence was seen in hybridoma cell lines tested with P. falciparum, whereas negative results were obtained when the cell lines were cross-reacted with other human species (P. vivax) and with a rodent malaria parasite (P. berghei)

  3. An ultrasensitive NanoLuc-based luminescence system for monitoring Plasmodium berghei throughout its life cycle.

    Science.gov (United States)

    De Niz, Mariana; Stanway, Rebecca R; Wacker, Rahel; Keller, Derya; Heussler, Volker T

    2016-04-21

    Bioluminescence imaging is widely used for cell-based assays and animal imaging studies, both in biomedical research and drug development. Its main advantages include its high-throughput applicability, affordability, high sensitivity, operational simplicity, and quantitative outputs. In malaria research, bioluminescence has been used for drug discovery in vivo and in vitro, exploring host-pathogen interactions, and studying multiple aspects of Plasmodium biology. While the number of fluorescent proteins available for imaging has undergone a great expansion over the last two decades, enabling simultaneous visualization of multiple molecular and cellular events, expansion of available luciferases has lagged behind. The most widely used bioluminescent probe in malaria research is the Photinus pyralis firefly luciferase, followed by the more recently introduced Click-beetle and Renilla luciferases. Ultra-sensitive imaging of Plasmodium at low parasite densities has not been previously achieved. With the purpose of overcoming these challenges, a Plasmodium berghei line expressing the novel ultra-bright luciferase enzyme NanoLuc, called PbNLuc has been generated, and is presented in this work. NanoLuc shows at least 150 times brighter signal than firefly luciferase in vitro, allowing single parasite detection in mosquito, liver, and sexual and asexual blood stages. As a proof-of-concept, the PbNLuc parasites were used to image parasite development in the mosquito, liver and blood stages of infection, and to specifically explore parasite liver stage egress, and pre-patency period in vivo. PbNLuc is a suitable parasite line for sensitive imaging of the entire Plasmodium life cycle. Its sensitivity makes it a promising line to be used as a reference for drug candidate testing, as well as the characterization of mutant parasites to explore the function of parasite proteins, host-parasite interactions, and the better understanding of Plasmodium biology. Since the substrate

  4. Transcript and protein expression profile of PF11_0394, a Plasmodium falciparum protein expressed in salivary gland sporozoites

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    Schlarman Maggie S

    2012-03-01

    Full Text Available Abstract Background Plasmodium falciparum malaria is a significant problem around the world today, thus there is still a need for new control methods to be developed. Because the sporozoite displays dual infectivity for both the mosquito salivary glands and vertebrate host tissue, it is a good target for vaccine development. Methods The P. falciparum gene, PF11_0394, was chosen as a candidate for study due to its potential role in the invasion of host tissues. This gene, which was selected using a data mining approach from PlasmoDB, is expressed both at the transcriptional and protein levels in sporozoites and likely encodes a putative surface protein. Using reverse transcription-polymerase chain reaction (RT-PCR and green fluorescent protein (GFP-trafficking studies, a transcript and protein expression profile of PF11_0394 was determined. Results The PF11_0394 protein has orthologs in other Plasmodium species and Apicomplexans, but none outside of the group Apicomplexa. PF11_0394 transcript was found to be present during both the sporozoite and erythrocytic stages of the parasite life cycle, but no transcript was detected during axenic exoerythrocytic stages. Despite the presence of transcript throughout several life cycle stages, the PF11_0394 protein was only detected in salivary gland sporozoites. Conclusions PF11_0394 appears to be a protein uniquely detected in salivary gland sporozoites. Even though a specific function of PF11_0394 has not been determined in P. falciparum biology, it could be another candidate for a new vaccine.

  5. New quinoline derivatives demonstrate a promising antimalarial activity against Plasmodium falciparum in vitro and Plasmodium berghei in vivo.

    Science.gov (United States)

    Soares, Roberta Reis; da Silva, José Marcio Fernandes; Carlos, Bianca Cecheto; da Fonseca, Camila Campos; de Souza, Laila Salomé Araújo; Lopes, Fernanda Valério; de Paula Dias, Rafael Mafra; Moreira, Paulo Otávio Lourenço; Abramo, Clarice; Viana, Gustavo Henrique Ribeiro; de Pila Varotti, Fernando; da Silva, Adilson David; Scopel, Kézia Katiani Gorza

    2015-06-01

    Malaria continues to be an important public health problem in the world. Nowadays, the widespread parasite resistance to many drugs used in antimalarial therapy has made the effective treatment of cases and control of the disease a constant challenge. Therefore, the discovery of new molecules with good antimalarial activity and tolerance to human use can be really important in the further treatment of the disease. In this study we have investigated the antiplasmodial activity of 10 synthetic compounds derived from quinoline, five of them combined to sulfonamide and five to the hydrazine or hydrazide group. The compounds were evaluated according to their cytotoxicity against HepG2 and HeLa cell lines, their antimalarial activity against CQ-sensitive and CQ-resistant Plasmodium falciparum strains and, finally, their schizonticide blood action in mice infected with Plasmodium berghei NK65. The compounds exhibited no cytotoxic action in HepG2 and HeLa cell lines when tested up to a concentration of 100 μg/mL. In addition, the hydrazine or hydrazide derivative compounds were less cytotoxic against cell lines and more active against CQ-sensitive and CQ-resistant P. falciparum strains, showing high SI (>1000 when SI was calculated using the CC50 from the 3D7 strain as reference). When tested in vivo, the hydrazine derivative 1f compound showed activity against the development of blood parasites similar to that observed with CQ, the reference drug. Interestingly, the 1f compound demonstrated the best LipE value (4.84) among all those tested in vivo. Considering the in vitro and in vivo activities of the compounds studied here and the LipE values, we believe the 1f compound to be the most promising molecule for further studies in antimalarial chemotherapy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. In vivo effect of chronic nicotine exposure on outcome of Plasmodium berghei ANKA malaria

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    Tsige Ketema

    2017-04-01

    Full Text Available Objective: To assess effect of nicotine, major addictive component of tobacco smoke, on outcomes of the deadly malaria parasite using mice as animal model. Methods: Male Swiss albino mice were treated with 100 and 200 µg/mL of nicotine in drinking water daily for 6 weeks followed by Plasmodium berghei ANKA (PbA infection. On the seventh day of post infection (p.i., physical, clinical, histopathological, biochemical and hematological parameters were assessed. Data were analyzed using SPSS software. Results: Nicotine was significantly (P < 0.05 positively associated with lower levels of hemoglobin (Hb, hematocrit (HCT, red blood cells (RBCs, C-reactive protein (CRP and uric acid (UA, higher risk to incidence of pulmonary edema, elevated level of liver and kidney biomarkers. Also significant increment (P < 0.01 of monocyte-lymphocyte count ratio (MLCR was observed. Risk to high temperature, lower platelet count, high parastemia and cerebral malaria was lesser in mice treated with nicotine (100 and 200 µg/mL followed by PbA infection than the positive control. Lack of neurological symptoms might be accounted to the anti-inflammatory property of nicotine that could inhibit production of pro-inflammatory mediators responsible for occurrence of cerebral malaria. Conclusions: This study showed that despite down regulation of most cerebral malaria symptoms nicotine was strongly associated with increased risk to most clinical symptoms of malaria. Thus, like in respiratory infections, nicotine use might enhance susceptibility to malaria.

  7. TRPV1 Antagonism by Capsazepine Modulates Innate Immune Response in Mice Infected with Plasmodium berghei ANKA

    Directory of Open Access Journals (Sweden)

    Elizabeth S. Fernandes

    2014-01-01

    Full Text Available Thousands of people suffer from severe malaria every year. The innate immune response plays a determinant role in host’s defence to malaria. Transient receptor potential vanilloid 1 (TRPV1 modulates macrophage-mediated responses in sepsis, but its role in other pathogenic diseases has never been addressed. We investigated the effects of capsazepine, a TRPV1 antagonist, in malaria. C57BL/6 mice received 105 red blood cells infected with Plasmodium berghei ANKA intraperitoneally. Noninfected mice were used as controls. Capsazepine or vehicle was given intraperitoneally for 6 days. Mice were culled on day 7 after infection and blood and spleen cell phenotype and activation were evaluated. Capsazepine decreased circulating but not spleen F4/80+Ly6G+ cell numbers as well as activation of both F4/80+and F4/80+Ly6G+ cells in infected animals. In addition, capsazepine increased circulating but not spleen GR1+ and natural killer (NK population, without interfering with natural killer T (NKT cell numbers and blood NK and NKT activation. However, capsazepine diminished CD69 expression in spleen NKT but not NK cells. Infection increased lipid peroxidation and the release of TNFα and IFNγ, although capsazepine-treated group exhibited lower levels of lipid peroxidation and TNFα. Capsazepine treatment did not affect parasitaemia. Overall, TRPV1 antagonism modulates the innate immune response to malaria.

  8. Adenovirus Particles that Display the Plasmodium falciparum Circumsporozoite Protein NANP Repeat Induce Sporozoite-Neutralizing Antibodies in Mice

    Science.gov (United States)

    Palma, Christopher; Overstreet, Michael G.; Guedon, Jean-Marc; Hoiczyk, Egbert; Ward, Cameron; Karen, Kasey A.; Zavala, Fidel; Ketner, Gary

    2011-01-01

    Adenovirus particles can be engineered to display exogenous peptides on their surfaces by modification of viral capsid proteins, and particles that display pathogen-derived peptides can induce protective immunity. We constructed viable recombinant adenoviruses that display B-cell epitopes from the Plasmodium falciparum circumsporozoite protein (PfCSP) in the major adenovirus capsid protein, hexon. Recombinants induced high-titer antibodies against CSP when injected intraperitoneally into mice. Serum obtained from immunized mice recognized both recombinant PfCSP protein and P. falciparum sporozoites, and neutralized P. falciparum sporozoites in vitro. Replicating adenovirus vaccines have provided economical protection against adenovirus disease for over three decades. The recombinants described here may provide a path to an affordable malaria vaccine in the developing world. PMID:21199707

  9. Functional characterization of Plasmodium berghei PSOP25 during ookinete development and as a malaria transmission-blocking vaccine candidate.

    Science.gov (United States)

    Zheng, Wenqi; Liu, Fei; He, Yiwen; Liu, Qingyang; Humphreys, Gregory B; Tsuboi, Takafumi; Fan, Qi; Luo, Enjie; Cao, Yaming; Cui, Liwang

    2017-01-05

    Plasmodium ookinete surface proteins as post-fertilization target antigens are potential malaria transmission-blocking vaccine (TBV) candidates. Putative secreted ookinete protein 25 (PSOP25) is a highly conserved ookinete surface protein, and has been shown to be a promising novel TBV target. Here, we further investigated the TBV activities of the full-length recombinant PSOP25 (rPSOP25) protein in Plasmodium berghei, and characterized the potential functions of PSOP25 during the P. berghei life-cycle. We expressed the full-length P. berghei PSOP25 protein in a prokaryotic expression system, and developed polyclonal mouse antisera and a monoclonal antibody (mAb) against the recombinant protein. Indirect immunofluorescence assay (IFA) and Western blot were used to test the specificity of antibodies. The transmission-blocking (TB) activities of antibodies were evaluated by the in vitro ookinete conversion assay and by direct mosquito feeding assay (DFA). Finally, the function of PSOP25 during Plasmodium development was studied by deleting the psop25 gene. Both polyclonal mouse antisera and anti-rPSOP25 mAb recognized the PSOP25 proteins in the parasites, and IFA showed the preferential expression of PSOP25 on the surface of zygotes, retorts and mature ookinetes. In vitro, these antibodies significantly inhibited ookinetes formation in an antibody concentration-dependent manner. In DFA, mice immunized with the rPSOP25 and those receiving passive transfer of the anti-rPSOP25 mAb reduced the prevalence of mosquito infection by 31.2 and 26.1%, and oocyst density by 66.3 and 63.3%, respectively. Genetic knockout of the psop25 gene did not have a detectable impact on the asexual growth of P. berghei, but significantly affected the maturation of ookinetes and the formation of midgut oocysts. The full-length rPSOP25 could elicit strong antibody response in mice. Polyclonal and monoclonal antibodies against PSOP25 could effectively block the formation of ookinetes in vitro

  10. Effectiveness of Gamma Rays in Attenuating Rodent Malaria Parasites of Plasmodium berghei in Blood of Mice

    International Nuclear Information System (INIS)

    Syaifudin, M.; Darlina; Rahardjo, T.; Tetriana, D.; Nurhayati, S.; Surniyantoro, H.N.E.; Kisnanto, T.

    2013-01-01

    Malaria is a major public health problem in Indonesia. Therefore, an effective vaccine against this disease is actively being sought by using gamma rays to attenuate the parasites. However, the safety and efficacy of the resulting vaccine are dependent on the precise irradiation dose. The aim of this research was to determine the exact time when the parasites are attenuated by gamma ray exposure. Mice blood containing Plasmodium berghei of 5,0 X 10 7 parasites/ml was irradiated with gamma rays at doses of 0, 150, 175 and 200 Gy (doses rate of 380 Gy/h) and then was injected intraperitoneally to mice at 0, 1, 2, 3, and 4 h post irradiation. The parasitemia (parasite density) in mouse blood was observed starting with day 2 and repeated every 2-4 days up to 28 days. The survival of the mice was also observed during the experiment. The results showed that the pre-patent period advanced with exposing infected blood to 150 and 175 Gy irradiations, suggesting some degree of attenuation. The amount of radiation required to render the parasites non-viable is about 175 Gy for an inoculum of a number of parasites, but a delay of 4 h resulted in the death of parasites. There was no difference in the infectivity of irradiated parasite injected 1 h and 2 h post irradiation in terms of parasitemia and the survival of mouse. For a dose of 200 Gy which was injected 2 h post irradiation, no parasitemia was found in the blood and animals which died after times varying from 1 to 4 weeks. We concluded that irradiated parasites should be injected into the host within 1 h after irradiation. (author)

  11. Inducible Costimulator Expressing T Cells Promote Parasitic Growth During Blood Stage Plasmodium berghei ANKA Infection

    Directory of Open Access Journals (Sweden)

    Gajendra M. Jogdand

    2018-05-01

    Full Text Available The lethality of blood stage Plasmodium berghei ANKA (PbA infection is associated with the expression of T-bet and production of cytokine IFN-γ. Expression of inducible costimulator (ICOS and its downstream signaling has been shown to play a critical role in the T-bet expression and IFN-γ production. Although earlier studies have examined the role of ICOS in the control of acute blood-stage infection of Plasmodium chabaudi chabaudi AS (a non-lethal model of malaria infection, its significance in the lethal blood-stage of PbA infection remains unclear. Thus, to address the seminal role of ICOS in lethal blood-stage of PbA infection, we treated PbA-infected mice with anti-ICOS antibody and observed that these mice survived longer than their infected counterparts with significantly lower parasitemia. Anti-ICOS treatment notably depleted ICOS expressing CD4+ and CD8+ T cells with a concurrent reduction in plasma IFN-γ, which strongly indicated that ICOS expressing T cells are major IFN-γ producers. Interestingly, we observed that while ICOS expressing CD4+ and CD8+ T cells produced IFN-γ, ICOS−CD8+ T cells were also found to be producers of IFN-γ. However, we report that ICOS+CD8+ T cells were higher producers of IFN-γ than ICOS−CD8+ T cells. Moreover, correlation of ICOS expression with IFN-γ production in ICOS+IFN-γ+ T cell population (CD4+ and CD8+ T cells suggested that ICOS and IFN-γ could positively regulate each other. Further, master transcription factor T-bet importantly involved in regulating IFN-γ production was also found to be expressed by ICOS expressing CD4+ and CD8+ T cells during PbA infection. As noted above with IFN-γ and ICOS, a positive correlation of expression of ICOS with the transcription factor T-bet suggested that both of them could regulate each other. Taken together, our results depicted the importance of ICOS expressing CD4+ and CD8+ T cells in malaria parasite growth and lethality through IFN

  12. The novel oxygenated chalcone, 2,4-dimethoxy-4'-butoxychalcone, exhibits potent activity against human malaria parasite Plasmodium falciparum in vitro and rodent parasites Plasmodium berghei and Plasmodium yoelii in vivo

    DEFF Research Database (Denmark)

    Chen, M; Brøgger Christensen, S; Zhai, L

    1997-01-01

    Previous studies have shown that licochalcone A, an oxygenated chalcone, exhibits antileishmanial and antimalarial activities. The present study was designed to examine the antimalarial activity of an analog of licochalcone A, 2,4-dimethoxy-4'-butoxychalcone (2,4mbc). 2,4mbc inhibited the in vitro...... activity and might be developed into a new antimalarial drug....... growth of both a chloroquine-susceptible (3D7) and a chloroquine-resistant (Dd2) strain of Plasmodium falciparum in a [3H]hypoxanthine uptake assay. The in vivo activity of 2,4mbc was tested in mice infected with Plasmodium berghei or Plasmodium yoelii and in rats infected with P. berghei. 2,4mbc...

  13. Re-assessing the relationship between sporozoite dose and incubation period in Plasmodium vivax malaria: a systematic re-analysis.

    Science.gov (United States)

    Lover, Andrew A; Coker, Richard J

    2014-05-01

    Infections with the malaria parasite Plasmodium vivax are noteworthy for potentially very long incubation periods (6-9 months), which present a major barrier to disease elimination. Increased sporozoite challenge has been reported to be associated with both shorter incubation and pre-patent periods in a range of human challenge studies. However, this evidence base has scant empirical foundation, as these historical analyses were limited by available analytic methods, and provides no quantitative estimates of effect size. Following a comprehensive literature search, we re-analysed all identified studies using survival and/or logistic models plus contingency tables. We have found very weak evidence for dose-dependence at entomologically plausible inocula levels. These results strongly suggest that sporozoite dosage is not an important driver of long-latency. Evidence presented suggests that parasite strain and vector species have quantitatively greater impacts, and the potential existence of a dose threshold for human dose-response to sporozoites. Greater consideration of the complex interplay between these aspects of vectors and parasites are important for human challenge experiments, vaccine trials, and epidemiology towards global malaria elimination.

  14. In vivo antimalarial activity of crude extracts and solvent fractions of leaves of Strychnos mitis in Plasmodium berghei infected mice.

    Science.gov (United States)

    Fentahun, Selamawit; Makonnen, Eyasu; Awas, Tesfaye; Giday, Mirutse

    2017-01-05

    Malaria is a major public health problem in the world which is responsible for death of millions particularly in sub-Saharan Africa. Today, the control of malaria has become gradually more complex due to the spread of drug-resistant parasites. Medicinal plants are the unquestionable source of effective antimalarials. The present study aimed to evaluate antiplasmodial activity and acute toxicity of the plant Strychnos mitis in Plasmodium berghei infected mice. Standard procedures were employed to investigate acute toxicity and 4-day suppressive effect of crude aqueous and hydro-methanolic extracts of the leaves of Strychnos mitis against P. berghei in Swiss albino mice. Water, n-hexane and chloroform fractions, obtained from crude hydro-methanolic extract, were also tested for their suppressive effect against P. berghei. All crude extracts revealed no obvious acute toxicity in mice up to the highest dose administered (2000 mg/kg). All crude and solvent fractions of the leaves of Strychnos mitis inhibited parasitaemia significantly (p antimalarial agent.

  15. Depletion of Plasmodium berghei plasmoredoxin reveals a non-essential role for life cycle progression of the malaria parasite.

    Science.gov (United States)

    Buchholz, Kathrin; Rahlfs, Stefan; Schirmer, R Heiner; Becker, Katja; Matuschewski, Kai

    2008-06-25

    Proliferation of the pathogenic Plasmodium asexual blood stages in host erythrocytes requires an exquisite capacity to protect the malaria parasite against oxidative stress. This function is achieved by a complex antioxidant defence system composed of redox-active proteins and low MW antioxidants. Here, we disrupted the P. berghei plasmoredoxin gene that encodes a parasite-specific 22 kDa member of the thioredoxin superfamily. The successful generation of plasmoredoxin knockout mutants in the rodent model malaria parasite and phenotypic analysis during life cycle progression revealed a non-vital role in vivo. Our findings suggest that plasmoredoxin fulfils a specialized and dispensable role for Plasmodium and highlights the need for target validation to inform drug development strategies.

  16. Studies on the transfer of protective immunity with lymphoid cells from mice immune to malaria sporozoites

    International Nuclear Information System (INIS)

    Verhave, J.P.; Strickland, G.T.; Jaffe, H.A.; Ahmed, A.

    1978-01-01

    In an effort to understand the mechanisms involved in the protective immunity to malarial sporozoites, an A/J mouse/Plasmodium berghei model was studied. Protective immunity could consistently be adoptively transferred only by using sublethal irradiation of recipients (500 R); a spleen equivalent (100 x 10 6 ) of donor cells from immune syngeneic mice; and a small booster immunization (1 x 10 4 ) of recipients with irradiation-attenuated sporozoites. Recipient animals treated in this manner were protected from lethal challenge with 1 x 10 4 nonattenuated sporozoites. Immune and nonimmune serum and spleen cells from nonimmune animals did not protect recipient mice. Fewer immune spleen cells (50 x 10 6 ) protected some recipients. In vitro treatment of immune spleen cells with anti-theta sera and complement abolished their ability to transfer protection. This preliminary study suggests that protective sporozoite immunity can be transferred with cells, and that it is T cell dependent

  17. Antimalarial activity of 80 % methanolic extract of Brassica nigra (L.) Koch. (Brassicaceae) seeds against Plasmodium berghei infection in mice.

    Science.gov (United States)

    Muluye, Abrham Belachew; Melese, Eshetie; Adinew, Getnet Mequanint

    2015-10-15

    Resistances to currently available drugs and insecticides, significant drug toxicities and costs and lack of vaccines currently complicated the treatment of malaria. A continued search for safe, effective and affordable plant-based antimalarial agents thus becomes crucial and vital in the face of these difficulties. The aim of the study was to evaluate the antimalarial activity of 80 % methanolic extract of the seeds of Brassica nigra against Plasmodium berghei infection in mice. Chloroquine sensitive Plasmodium berghei (ANKA strain) was used to test the antimalarial activity of the extract. In suppressive and prophylactic models, Swiss albino male mice were randomly grouped into five groups of five mice each. Group I mice were treated with the vehicle, group II, III and IV were treated with 100, 200, and 400 mg/kg of the extract, respectively and the last group (V) mice were treated with chloroquine (10 mg/kg). The level of parasitemia, survival time and variation in weight of mice were used to determine the antimalarial activity of the extract. Chemosuppressive activities produced by the extract of the seeds of Brassica nigra were 21.88, 50.00 (P activities were 17.42, 21.21 and 53.79 % (P activities and the plant may contain biologically active principles which are relevant in the treatment and prophylaxis of malaria, thus supporting further studies of the plant for its active components.

  18. Antiplasmodial effects of the aqueous ethanolic seed extract of Ziziphus mauritiana against Plasmodium berghei in Swiss albino mice

    Directory of Open Access Journals (Sweden)

    Tulika Mishra

    2014-08-01

    Full Text Available Ziziphus mauritiana is a fruit tree used traditionally since long back for wound healing, immunepotentiator, asthma, sedative, stomachic, styptic, as tonic etc. The present study determines the antiplasmodial effect of aqueous ethanolic seed extract against Chloroquine sensitive Plasmodium berghei berghei nk65 infection in Swiss albino mice. Based upon the acute toxicity data three different doses (100, 200, 400 mg/kg body weight of the plant extract was chosen to study the blood schizonticidal activity in early infection and in established infection and was compared with chloroquine. The Prophylactic activity was also assessed and compared with pyrimethamine. No mortality was observed in acute toxicity study however, above the dose of 1000 mg/kg animals showed the lethargic behaviour. In early infection, and in established infection the doses (100-400 mg/kg b.wt was found to cause significant (P<0.001 suppression of infection in a dose dependent manner as compared to control. Although, the activity was lower than standard chloroquine. Similarly, the extract at all the doses caused the suppression in repository activity but was lower than pyrimethamine. The mean survival time was also increased in mice by 14 and 17 days at the doses of 200 and 400 mg/kg respectively, whereas the control group sustained only for 7 days. Thus, the seed extract showed the effectiveness against plasmodium infection.

  19. Curcumin-arteether combination therapy of Plasmodium berghei-infected mice prevents recrudescence through immunomodulation.

    Directory of Open Access Journals (Sweden)

    Palakkod G Vathsala

    Full Text Available Earlier studies in this laboratory have shown the potential of artemisinin-curcumin combination therapy in experimental malaria. In a parasite recrudescence model in mice infected with Plasmodium berghei (ANKA, a single dose of alpha,beta-arteether (ART with three oral doses of curcumin prevented recrudescence, providing almost 95% protection. The parasites were completely cleared in blood with ART-alone (AE or ART+curcumin (AC treatments in the short-term, although the clearance was faster in the latter case involving increased ROS generation. But, parasites in liver and spleen were not cleared in AE or AC treatments, perhaps, serving as a reservoir for recrudescence. Parasitemia in blood reached up to 60% in AE-treated mice during the recrudescence phase, leading to death of animals. A transient increase of up to 2-3% parasitemia was observed in AC-treatment, leading to protection and reversal of splenomegaly. A striking increase in spleen mRNA levels for TLR2, IL-10 and IgG-subclass antibodies but a decrease in those for INFγ and IL-12 was observed in AC-treatment. There was a striking increase in IL-10 and IgG subclass antibody levels but a decrease in INFγ levels in sera leading to protection against recrudescence. AC-treatment failed to protect against recrudescence in TLR2(-/- and IL-10(-/- animals. IL-10 injection to AE-treated wild type mice and AC-treated TLR2(-/- mice was able to prolong survival. Blood from the recrudescence phase in AE-treatment, but not from AC-treatment, was able to reinfect and kill naïve animals. Sera from the recrudescence phase of AC-treated animals reacted with several parasite proteins compared to that from AE-treated animals. It is proposed that activation of TLR2-mediated innate immune response leading to enhanced IL-10 production and generation of anti-parasite antibodies contribute to protective immunity in AC-treated mice. These results indicate a potential for curcumin-based combination therapy to

  20. Interrogating the Plasmodium Sporozoite Surface: Identification of Surface-Exposed Proteins and Demonstration of Glycosylation on CSP and TRAP by Mass Spectrometry-Based Proteomics.

    Directory of Open Access Journals (Sweden)

    Kristian E Swearingen

    2016-04-01

    Full Text Available Malaria parasite infection is initiated by the mosquito-transmitted sporozoite stage, a highly motile invasive cell that targets hepatocytes in the liver for infection. A promising approach to developing a malaria vaccine is the use of proteins located on the sporozoite surface as antigens to elicit humoral immune responses that prevent the establishment of infection. Very little of the P. falciparum genome has been considered as potential vaccine targets, and candidate vaccines have been almost exclusively based on single antigens, generating the need for novel target identification. The most advanced malaria vaccine to date, RTS,S, a subunit vaccine consisting of a portion of the major surface protein circumsporozoite protein (CSP, conferred limited protection in Phase III trials, falling short of community-established vaccine efficacy goals. In striking contrast to the limited protection seen in current vaccine trials, sterilizing immunity can be achieved by immunization with radiation-attenuated sporozoites, suggesting that more potent protection may be achievable with a multivalent protein vaccine. Here, we provide the most comprehensive analysis to date of proteins located on the surface of or secreted by Plasmodium falciparum salivary gland sporozoites. We used chemical labeling to isolate surface-exposed proteins on sporozoites and identified these proteins by mass spectrometry. We validated several of these targets and also provide evidence that components of the inner membrane complex are in fact surface-exposed and accessible to antibodies in live sporozoites. Finally, our mass spectrometry data provide the first direct evidence that the Plasmodium surface proteins CSP and TRAP are glycosylated in sporozoites, a finding that could impact the selection of vaccine antigens.

  1. Plasmodium vivax sporozoite challenge in malaria-naïve and semi-immune Colombian volunteers

    DEFF Research Database (Denmark)

    Arévalo-Herrera, Myriam; Forero-Peña, David A.; Rubiano, Kelly

    2014-01-01

    induced in naïve and semi-immune volunteers by infected mosquito bites was compared. Methods: Seven malaria-naïve and nine semi-immune Colombian adults (n = 16) were subjected to the bites of 2-4 P. vivax sporozoite-infected Anopheles mosquitoes. Parasitemia levels, malaria clinical manifestations...

  2. Flow cytometry-assisted rapid isolation of recombinant Plasmodium berghei parasites exemplified by functional analysis of aquaglyceroporin

    Science.gov (United States)

    Kenthirapalan, Sanketha; Waters, Andrew P.; Matuschewski, Kai; Kooij, Taco W.A.

    2012-01-01

    The most critical bottleneck in the generation of recombinant Plasmodium berghei parasites is the mandatory in vivo cloning step following successful genetic manipulation. This study describes a new technique for rapid selection of recombinant P. berghei parasites. The method is based on flow cytometry to isolate isogenic parasite lines and represents a major advance for the field, in that it will speed the generation of recombinant parasites as well as cut down on animal use significantly. High expression of GFP during blood infection, a prerequisite for robust separation of transgenic lines by flow cytometry, was achieved. Isogenic recombinant parasite populations were isolated even in the presence of a 100-fold excess of wild-type (WT) parasites. Aquaglyceroporin (AQP) loss-of-function mutants and parasites expressing a tagged AQP were generated to validate this approach. aqp− parasites grow normally within the WT phenotypic range during blood infection of NMRI mice. Similarly, colonization of the insect vector and establishment of an infection after mosquito transmission were unaffected, indicating that AQP is dispensable for life cycle progression in vivo under physiological conditions, refuting its use as a suitable drug target. Tagged AQP localized to perinuclear structures and not the parasite plasma membrane. We suggest that flow-cytometric isolation of isogenic parasites overcomes the major roadblock towards a genome-scale repository of mutant and transgenic malaria parasite lines. PMID:23137753

  3. In Vivo Antimalarial Effects of Iranian Flora Artemisia khorassanica against Plasmodium berghei and Pharmacochemistry of its Natural Components

    Directory of Open Access Journals (Sweden)

    M Amini

    2010-02-01

    Full Text Available "nBackground: The aim of this study was to evaluate the antimalarial effects of Iranian flora Artemisia khorassanica against Plasmodium berghei in vivo and pharmacochemistry of its natural components."nMethods: The aerial parts of Iranian flora A. khorasanica were collected at flowering stage from Khorassan Province, northeastern Iran in 2008. They were air-dried at room temperature; powder was macerated in methanol and the extract defatted in refrigerator, filtered, diluted with water, then eluted with n-hexane and finally non-polar components were identified through Gas Chromatography and Mass Spectroscopy (GC-MS. Toxicity of herbal extracts was assessed on naïve NMRI mice, and its anti-malarial efficacy was investigated on infected Plasmodium berghei animals. This is the first ap­plication on A. khorssanica extract for treatment of murine malaria. The significance of differences was determined by Analysis of Variances (ANOVA and Student's t-test using Graph Pad Prism Software."nResults: The herbal extract was successfully tested in vivo for its anti-plasmodial activity through ar­temisin composition, which is widely used as a standard malaria treatment."nConclusion: Although, this study confirmed less anti-malarial effects of A. khorssanica against mur­ine malaria in vivo, how­ever there are some evidences on reducing pathophysiology by this medica­tion. In complementary assay, major components were detected by GC-MS analysis in herbal extract including chrysanthe­none (7.8%, palmitic acid (7.4% and cis-thujone (5.8%.  The most retention indices of the compo­nent are given as n-eicosane, palmitic acid and n-octadecane.

  4. A novel genetic technique in Plasmodium berghei allows liver stage analysis of genes required for mosquito stage development and demonstrates that de novo heme synthesis is essential for liver stage development in the malaria parasite.

    Directory of Open Access Journals (Sweden)

    Upeksha L Rathnapala

    2017-06-01

    Full Text Available The combination of drug resistance, lack of an effective vaccine, and ongoing conflict and poverty means that malaria remains a major global health crisis. Understanding metabolic pathways at all parasite life stages is important in prioritising and targeting novel anti-parasitic compounds. The unusual heme synthesis pathway of the rodent malaria parasite, Plasmodium berghei, requires eight enzymes distributed across the mitochondrion, apicoplast and cytoplasm. Deletion of the ferrochelatase (FC gene, the final enzyme in the pathway, confirms that heme synthesis is not essential in the red blood cell stages of the life cycle but is required to complete oocyst development in mosquitoes. The lethality of FC deletions in the mosquito stage makes it difficult to study the impact of these mutations in the subsequent liver stage. To overcome this, we combined locus-specific fluorophore expression with a genetic complementation approach to generate viable, heterozygous oocysts able to produce a mix of FC expressing and FC deficient sporozoites. These sporozoites show normal motility and can invade liver cells, where FC deficient parasites can be distinguished by fluorescence and phenotyped. Parasites lacking FC exhibit a severe growth defect within liver cells, with development failure detectable in the early to mid stages of liver development in vitro. FC deficient parasites could not complete liver stage development in vitro nor infect naïve mice, confirming liver stage arrest. These results validate the heme pathway as a potential target for prophylactic drugs targeting liver stage parasites. In addition, we demonstrate that our simple genetic approach can extend the phenotyping window beyond the insect stages, opening considerable scope for straightforward reverse genetic analysis of genes that are dispensable in blood stages but essential for completing mosquito development.

  5. A novel genetic technique in Plasmodium berghei allows liver stage analysis of genes required for mosquito stage development and demonstrates that de novo heme synthesis is essential for liver stage development in the malaria parasite.

    Science.gov (United States)

    Rathnapala, Upeksha L; Goodman, Christopher D; McFadden, Geoffrey I

    2017-06-01

    The combination of drug resistance, lack of an effective vaccine, and ongoing conflict and poverty means that malaria remains a major global health crisis. Understanding metabolic pathways at all parasite life stages is important in prioritising and targeting novel anti-parasitic compounds. The unusual heme synthesis pathway of the rodent malaria parasite, Plasmodium berghei, requires eight enzymes distributed across the mitochondrion, apicoplast and cytoplasm. Deletion of the ferrochelatase (FC) gene, the final enzyme in the pathway, confirms that heme synthesis is not essential in the red blood cell stages of the life cycle but is required to complete oocyst development in mosquitoes. The lethality of FC deletions in the mosquito stage makes it difficult to study the impact of these mutations in the subsequent liver stage. To overcome this, we combined locus-specific fluorophore expression with a genetic complementation approach to generate viable, heterozygous oocysts able to produce a mix of FC expressing and FC deficient sporozoites. These sporozoites show normal motility and can invade liver cells, where FC deficient parasites can be distinguished by fluorescence and phenotyped. Parasites lacking FC exhibit a severe growth defect within liver cells, with development failure detectable in the early to mid stages of liver development in vitro. FC deficient parasites could not complete liver stage development in vitro nor infect naïve mice, confirming liver stage arrest. These results validate the heme pathway as a potential target for prophylactic drugs targeting liver stage parasites. In addition, we demonstrate that our simple genetic approach can extend the phenotyping window beyond the insect stages, opening considerable scope for straightforward reverse genetic analysis of genes that are dispensable in blood stages but essential for completing mosquito development.

  6. Interactions between the intestinal flagellates Giardia muris and Spironucleus muris and the blood parasites Babesia microti, Plasmodium yoelii and Plasmodium berghei in mice.

    Science.gov (United States)

    Brett, S J; Cox, F E

    1982-08-01

    In mice infected with the intestinal flagellates Giardia muris or Spironucleus muris, together with the blood parasites Babesia microti or Plasmodium yoelii, there is a temporary decrease of flagellate cyst output coincident with the peak of the blood parasite infections, followed by a rapid return to normal levels. This decrease in cyst output is correlated with decreased numbers of trophozoites in the small intestine. The effect on S. muris is more marked than that on G. muris. Neither blood parasites has any effect on the total duration of the flagellate infection and the flagellates do not affect the blood parasites. In mice infected with G. muris or S. muris and P. berghei there is also a decrease in cyst output but this is less apparent than in infections with B. microti or P. yoelii because of the fatal nature of the P. berghei infection. It is suggested that the decrease in cyst output is probably due to changes in the contents of the small intestine or to non-specific immunological factors rather than to specific immunological changes.

  7. Evidência da ação antiparasitária da azitromicina na infecção experimental de camundongos pelo Plasmodium berghei

    Directory of Open Access Journals (Sweden)

    Gakiya Erika

    2001-01-01

    Full Text Available A azitromicina debelou a infecção experimental de camundongos pelo Plasmodium berghei quando administrada, pela via oral e durante 28 dias, na dose de 100mg/kg, iniciada no mesmo dia em que os animais foram infectados. Mediante uso de 10mg/kg houve insucesso. Os resultados obtidos suscitam investigações complementares sobre a referida atividade antiparasitária desse medicamento.

  8. Selection of drug resistant mutants from random library of Plasmodium falciparum dihydrofolate reductase in Plasmodium berghei model

    OpenAIRE

    Tipsuwan, Wachiraporn; Srichairatanakool, Somdet; Kamchonwongpaisan, Sumalee; Yuthavong, Yongyuth; Uthaipibull, Chairat

    2011-01-01

    Abstract Background The prevalence of drug resistance amongst the human malaria Plasmodium species has most commonly been associated with genomic mutation within the parasites. This phenomenon necessitates evolutionary predictive studies of possible resistance mutations, which may occur when a new drug is introduced. Therefore, identification of possible new Plasmodium falciparum dihydrofolate reductase (PfDHFR) mutants that confer resistance to antifolate drugs is essential in the process of...

  9. Molecular characterization of calreticulin from Anopheles stephensi midgut cells and functional assay of the recombinant calreticulin with Plasmodium berghei ookinetes.

    Science.gov (United States)

    Borhani Dizaji, Nahid; Basseri, Hamid Reza; Naddaf, Saied Reza; Heidari, Mansour

    2014-10-25

    Transmission blocking vaccines (TBVs) that target the antigens on the midgut epithelium of Anopheles mosquitoes are among the promising tools for the elimination of the malaria parasite. Characterization and analysis of effective antigens is the first step to design TBVs. Calreticulin (CRT), a lectin-like protein, from Anopheles albimanus midgut, has shown antigenic features, suggesting a promising and novel TBV target. CRT is a highly conserved protein with similar features in vertebrates and invertebrates including anopheline. We cloned the full-length crt gene from malaria vector, Anopheles stephensi (AsCrt) and explored the interaction of recombinant AsCrt protein, expressed in a prokaryotic system (pGEX-6p-1), with surface proteins of Plasmodium berghei ookinetes by immunofluorescence assay. The cellular localization of AsCrt was determined using the baculovirus expression system. Sequence analysis of the whole cDNA of AsCrt revealed that AsCrt contains an ORF of 1221 bp. The amino acid sequence of AsCrt protein obtained in this study showed 64% homology with similar protein in human. The AsCrt shares the most common features of CRTs from other species. This gene encodes a 406 amino-acid protein with a molecular mass of 46 kDa, which contains a predicted 16 amino-acid signal peptides, conserved cysteine residues, a proline-rich region, and highly acidic C-terminal domain with endoplasmic reticulum retrieval sequence HDEL. The production of GST-AsCrt recombinant protein was confirmed by Western blot analysis using an antibody against the GST protein. The FITC-labeled GST-AsCrt exhibited a significant interaction with P. berghei ookinete surface proteins. Purified recombinant GST-AsCrt, labeled with FITC, displayed specific binding to the surface of P. berghei ookinetes in comparison with control. Moreover, the expression of AsCrt in baculovirus expression system indicated that AsCrt was localized on the surface of Sf9 cells. Our results suggest that AsCrt could

  10. Evaluation on the effectiveness chemoprophylaxis of chloroquine to irradiated plasmodium berghei by in vivo

    International Nuclear Information System (INIS)

    Darlina; Teja Kisnanto; Citra Ayu Prapmaningtyas

    2016-01-01

    Chloroquine is a compound commonly used as chemoprophylaxis in malaria research. In the malaria vaccine research used chemoprophylaxis that combined with vaccine material was studied to prevent volunteers from malaria. The purpose of the study was to evaluate the efficacy of chloroquine in inhibiting the growth of malaria parasites after radiation. The effectiveness of chloroquine was shown to inhibit the growth P. berghei growth in experimental animals. The study was conducted in vivo with chloroquine administered orally as 0, 5, 10, and 15 mg/kg of body weight daily for 4 days in mice that had been injected with infectious and radiation P. berghei 175 Gy. Density of parasites in the blood, and percent survival was observed every 2 days for 43 days. The results show until the 20"t"h day is not found parasites in the blood of mice immunized and treated Chloroquine. The chloroquine 10 mg/kg is more effective than 5 and 15 mg/kg as observed in percentage of inhibition and survival of mice. (author)

  11. Controlled Human Malaria Infection of Tanzanians by Intradermal Injection of Aseptic, Purified, Cryopreserved Plasmodium falciparum Sporozoites

    NARCIS (Netherlands)

    Shekalaghe, S.; Rutaihwa, M.; Billingsley, P.F.; Chemba, M.; Daubenberger, C.A.; James, E.R.; Mpina, M.; Juma, O. Ali; Schindler, T.; Huber, E.; Gunasekera, A.; Manoj, A.; Simon, B.; Saverino, E.; Church, L.W.; Hermsen, C.C.; Sauerwein, R.W.; Plowe, C.; Venkatesan, M.; Sasi, P.; Lweno, O.; Mutani, P.; Hamad, A.; Mohammed, A.; Urassa, A.; Mzee, T.; Padilla, D.; Ruben, A.; Sim, B.K.; Tanner, M.; Abdulla, S.; Hoffman, S.L.

    2014-01-01

    Controlled human malaria infection (CHMI) by mosquito bite has been used to assess anti-malaria interventions in > 1,500 volunteers since development of methods for infecting mosquitoes by feeding on Plasmodium falciparum (Pf) gametocyte cultures. Such CHMIs have never been used in Africa. Aseptic,

  12. The Puf-family RNA-binding protein Puf2 controls sporozoite conversion to liver stages in the malaria parasite.

    Directory of Open Access Journals (Sweden)

    Katja Müller

    Full Text Available Malaria is a vector-borne infectious disease caused by unicellular, obligate intracellular parasites of the genus Plasmodium. During host switch the malaria parasite employs specialized latent stages that colonize the new host environment. Previous work has established that gametocytes, sexually differentiated stages that are taken up by the mosquito vector, control expression of genes required for mosquito colonization by translational repression. Sexual parasite development is controlled by a DEAD-box RNA helicase of the DDX6 family, termed DOZI. Latency of sporozoites, the transmission stage injected during an infectious blood meal, is controlled by the eIF2alpha kinase IK2, a general inhibitor of protein synthesis. Whether RNA-binding proteins participate in translational regulation in sporozoites remains to be studied. Here, we investigated the roles of two RNA-binding proteins of the Puf-family, Plasmodium Puf1 and Puf2, during sporozoite stage conversion. Our data reveal that, in the rodent malaria parasite P. berghei, Puf2 participates in the regulation of IK2 and inhibits premature sporozoite transformation. Inside mosquito salivary glands puf2⁻ sporozoites transform over time to round forms resembling early intra-hepatic stages. As a result, mutant parasites display strong defects in initiating a malaria infection. In contrast, Puf1 is dispensable in vivo throughout the entire Plasmodium life cycle. Our findings support the notion of a central role for Puf2 in parasite latency during switch between the insect and mammalian hosts.

  13. Sporozoite Route of Infection Influences In Vitro var Gene Transcription of Plasmodium falciparum Parasites From Controlled Human Infections.

    Science.gov (United States)

    Dimonte, Sandra; Bruske, Ellen I; Hass, Johanna; Supan, Christian; Salazar, Carmen L; Held, Jana; Tschan, Serena; Esen, Meral; Flötenmeyer, Matthias; Koch, Iris; Berger, Jürgen; Bachmann, Anna; Sim, Betty K L; Hoffman, Stephen L; Kremsner, Peter G; Mordmüller, Benjamin; Frank, Matthias

    2016-09-15

    Antigenic variation in Plasmodium falciparum is mediated by the multicopy var gene family. Each parasite possesses about 60 var genes, and switching between active var loci results in antigenic variation. In the current study, the effect of mosquito and host passage on in vitro var gene transcription was investigated. Thirty malaria-naive individuals were inoculated by intradermal or intravenous injection with cryopreserved, isogenic NF54 P. falciparum sporozoites (PfSPZ) generated from 1 premosquito culture. Microscopic parasitemia developed in 22 individuals, and 21 in vitro cultures were established. The var gene transcript levels were determined in early and late postpatient cultures and in the premosquito culture. At the early time point, all cultures preferentially transcribed 8 subtelomeric var genes. Intradermal infections had higher var gene transcript levels than intravenous infections and a significantly longer intrahost replication time (P = .03). At the late time point, 9 subtelomeric and 8 central var genes were transcribed at the same levels in almost all cultures. Premosquito and late postpatient cultures transcribed the same subtelomeric and central var genes, except for var2csa  The duration of intrahost replication influences in vitro var gene transcript patterns. Differences between premosquito and postpatient cultures decrease with prolonged in vitro growth. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  14. Potential antimalarial activity of Methyl Jasmonate and its effect on lipid profiles in Plasmodium Berghei infected mice.

    Science.gov (United States)

    Oyinloye, Oladapo E; Kosoko, Ayokulehin M; Emikpe, Benjamin; Falade, Catherine O; Ademowo, Olusegun G

    2015-09-01

    The antimalarial activity and lipid profiles of Methyl Jasmonate (MJ) were investigated against established malaria infection in vivo using BALB/c mice. Arteether (AE) and chloroquine (CQ) were used as reference drugs while ethanol was used as the vehicle for drug delivery for MJ. Mice treated with 10 and 25 mg/kg MJ showed a remarkable reduction in percentage parasitemia by 68.3% and 78.2% on day 10(post treatment) respectively while 45.4% and 87.2% reduction in percentage parasitemia were observed in the group treated with 50 mg/kg on day 3 and 10 (post treatment) respectively. The highest mean survival time was observed in CQ followed by AE and MJ in dose-dependent manner. A progressive decrease in packed cell volume (PCV) was observed in infected untreated mice which led to the death of all the mice by day 9 (post treatment). Infected mice treated with MJ showed reduced level of HDL and LDL compared with infected untreated group. As the dose of MJ increased in infected mice cholesterol levels increased while there was reduction in triglyceride. Overall there was marked decrease in parasitemia in Plasmodium berghei infected mice treated with graded doses of MJ but appears to have reduced antimalarial activity compared with CQ and AE.

  15. Immune Responses and Protection of Aotus Monkeys Immunized with Irradiated Plasmodium vivax Sporozoites

    Science.gov (United States)

    2011-01-01

    The experimental protocol was approved by the Animal Ethical Committee of the Universidad del Valle (Cali). Parasite and irradiation. Plasmodium...three repeats ofpll (GDRADGPA) and (ANGAGNQPG) sequences, derived from VK210 and VK247 CS variants, respectively. A non-malaria related peptide Ptt30...Universidad del Valle and Centro Internacional de Vacunas, Cali, Colombia, E-mails: alejovi@hotmail.com, anbonelo@yahoo.com, alejcaste@yahoo.com

  16. High-Affinity Accumulation of Chloroquine by Mouse Erythrocytes Infected with Plasmodium berghei

    Science.gov (United States)

    Fitch, Coy D.; Yunis, Norman G.; Chevli, Rekha; Gonzalez, Yolanda

    1974-01-01

    Washed erythrocytes infected with chloroquine-susceptible (CS) or with chloroquine-resistant (CR) P. berghei were used in model systems in vitro to study the accumulation of chloroquine with high affinity. The CS model could achieve distribution ratios (chloroquine in cells: chloroquine in medium) of 100 in the absence of substrate. 200—300 in the presence of 10 mM pyruvate or lactate, and over 600 in the presence of 1 mM glucose or glycerol. In comparable studies of the CR model, the distribution ratios were 100 in the absence of substrate and 300 or less in the presence of glucose or glycerol. The presence of lactate stimulated chloroquine accumulation in the CR model, whereas the presence of pyruvate did not. Lactate production from glucose and glycerol was undiminished in the CR model, and ATP concentrations were higher than in the CS model. Cold, iodoacetate, 2,4-dinitrophenol, or decreasing pH inhibited chloroquine accumulation in both models. These findings demonstrate substrate involvement in the accumulation of chloroquine with high affinity. In studies of the CS model, certain compounds competitively inhibited chloroquine accumulation, while others did not. This finding is attributable to a specific receptor that imposes structural constraints on the process of accumulation. For chloroquine analogues, the position and length of the side chain, the terminal nitrogen atom of the side chain, and the nitrogen atom in the quinoline ring are important determinants of binding to this receptor. PMID:4600044

  17. Ethnobotanical survey of antimalarial plants in Awash-Fentale District of Afar Region of Ethiopia and in vivo evaluation of selected ones against Plasmodium berghei

    Directory of Open Access Journals (Sweden)

    Nega Alelign

    2018-01-01

    Full Text Available Objective: To document plants used in traditional treatment of malaria in the Awash-Fentale District, the Afar Region of Ethiopia, and to evaluate antimalarial activity of selected ones against Plasmodium berghei in mice. Methods: Semi-structured interviews were carried out with purposively selected informants in the District to gather information on plants used in the traditional treatment of malaria. Standard procedures were used to investigate acute toxicity and a four-day suppressive effect of crude aqueous and ethanol extracts of the leaves of the two most frequently cited plants [Aloe trichosantha (A. trichosantha and Cadaba rotundifolia (C. rotundifolia] against Plasmodium berghei in Swiss albino mice. Results: The informants cited a total of 17 plants used in the traditional treatment of malaria in Awash-Fentale District. Plant parts were prepared as infusions or decoctions. Leaf was the most commonly cited (44% plant part, followed by stem (22%. Shrubs were the most frequently cited (63% medicine source followed by trees (21%. Of the 17 plants, C. rotundifolia and A. trichosantha were the most frequently mentioned plants in the district. Ethanol extracts of the leaves of C. rotundifolia and A. trichosantha suppressed P. berghei parasitaemia significantly accounting for 53.73% and 49.07%, respectively at 900 mg/kg. The plants were found to be non-toxic up to a dose of 1 500 mg/kg. Conclusions: Seventeen plant species were reported to be used for treatment of malaria in the Awash Fentale Distinct, among which A. trichosantha and C. rotundifolia were the most preferred ones. P. berghei suppressive activity of these plants may partly explain their common use in the community.

  18. Quantitative real-time PCR analysis of Anopheles dirus TEP1 and NOS during Plasmodium berghei infection, using three reference genes

    Directory of Open Access Journals (Sweden)

    Jonathan W.K. Liew

    2017-07-01

    Full Text Available Quantitative reverse transcription PCR (qRT-PCR has been an integral part of characterizing the immunity of Anopheles mosquitoes towards Plasmodium invasion. Two anti-Plasmodium factors of Anopheles, thioester-containing protein 1 (TEP1 and nitric oxide synthase (NOS, play a role in the refractoriness of Anopheles towards Plasmodium infection and are generally expressed during infection. However, these are less studied in Anopheles dirus, a dominant malaria vector in Southeast Asia. Furthermore, most studies used a single reference gene for normalization during gene expression analysis without proper validation. This may lead to erroneous quantification of expression levels. Therefore, the present study characterized and investigated the expression profiles of TEP1 and NOS of Anopheles dirus during P. berghei infection. Prior to that, the elongation factor 1-alpha (EF1, actin 1 (Act and ribosomal protein S7 (S7 genes were validated for their suitability as a set of reference genes. TEP1 and NOS expressions in An. dirus were found to be significantly induced after P. berghei infection.

  19. Antiplasmodial activity of eco-friendly synthesized palladium nanoparticles using Eclipta prostrata extract against Plasmodium berghei in Swiss albino mice.

    Science.gov (United States)

    Rajakumar, Govindasamy; Rahuman, Abdul Abdul; Chung, Ill-Min; Kirthi, Arivarasan Vishnu; Marimuthu, Sampath; Anbarasan, Karunanithi

    2015-04-01

    Malaria is an infectious disease caused by the Plasmodium parasite that continues to be a health issue for humans. It is one of the most common pathogenic factors of morbidity and mortality. Palladium nanoparticles (Pd NPs) have been used as target antimicrobial compounds, as a catalyst to manufacture pharmaceuticals, degrade harmful environmental pollutants, and as sensors for the detection of various analyses. The aim of this study was to investigate the antiplasmodial activity of synthesized Pd NPs by using leaf aqueous extract of Eclipta prostrata against Plasmodium berghei in Swiss albino mice. The synthesized Pd NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning electron microscopy (SEM) with Energy dispersive X-ray spectroscopy (EDX), and High-resolution transmission electron microscope (HRTEM) with the Selected area (electron) diffraction (SAED). The XRD peaks appeared at 35.61°, 44.27°, 56.40°, and 74.51°, which correspond to (111), (200), (220), and (311) planes for palladium, respectively. The FTIR spectra that were carried out to identify the potential biomolecule of synthesized Pd NPs showed the peaks at 3361, 1540, 1399, 1257, 1049, and 659 in the region of 4000-500 cm(-1). The SEM images showed aggregation of NPs with an average size of 63 ± 1.4. The HRTEM images of the precipitated solid phase obtained after termination of the reaction of E. prostrata aqueous leaf extract were in the range from 18 to 64 nm with an average size of 27 ± 1.3 nm. The in vivo antiplasmodial assay was carried out as per Peters' 4-day suppressive test, and the synthesized Pd NP-treated mice group showed reduction of parasitemia by 78.13% with an inhibitory concentration (IC)50 value of 16.44 mg/kg/body weight. The growth inhibition of E. prostrata aqueous leaf extract, palladium acetate, and synthesized Pd NPs showed the IC20, IC50, and IC90 values of 1.90, 10.29, and 64.11; 4.49, 9.84, and 23.04; and 4.34, 8

  20. Oxygen consumption in Plasmodium berghei-infected murine red cells: a direct spectrophotometric assay in intact erythrocytes.

    Science.gov (United States)

    Deslauriers, R; Moffatt, D J; Smith, I C

    1986-05-29

    A spectrophotometric assay has been devised to measure oxygen consumption non-invasively in intact murine red cells parasitized by Plasmodium berghei. The method uses oxyhemoglobin in the erythrocytes both as a source of oxygen and as an indicator of oxygen consumption. Spectra of intact cells show broad peaks and sloping baselines due to light-scattering. In order to ascertain the number of varying components in the 370-450 nm range, the resolution of the spectra was enhanced using Fourier transforms of the frequency domain spectra. Calculation of oxygen consumption was carried out for two-component systems (oxyhemoglobin, deoxyhemoglobin) using absorbances at 415 and 431 nm. Samples prepared from highly parasitized mice (greater than 80% parasitemia, 5% hematocrit) showed oxygen consumption rates of (4-8) X 10(-8) microliter/cell per h. This rate was not attributable to the presence of white cells or reticulocytes. The rate of oxygen consumption in the erythrocytes is shown to be modulated by various agents: the respiratory inhibitors NaN3 and KCN (1 mM) reduced oxygen consumption 2-3-fold; salicylhydroxamic acid (2.5 mM) caused a 20% reduction in rate and 10 mM NaN3, completely blocked deoxygenation. Antimalarial drugs and metal-chelating agents were also tested. Chloroquine, EDTA and desferal (desferoxamine mesylate) did not decrease the deoxygenation rate of hemoglobin in parasitized cells. Quinacrine, quinine and primaquine reduced the rate of formation of deoxyhemoglobin but also produced substantial quantities of methemoglobin. The lipophilic chelator, 5-hydroxyquinoline, decreased the rate of deoxygenation one-third. The spectrophotometric assay provides a convenient means to monitor oxygen consumption in parasitized red cells, to test the effects of various agents thereon, and potentially to explore possible mechanisms for oxygen utilization.

  1. In Vivo Hemozoin Kinetics after Clearance of Plasmodium berghei Infection in Mice

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    Rosangela Frita

    2012-01-01

    Full Text Available Hemozoin (Hz is released into the blood stream after rupture of infected red blood cells (iRBCs at the end of each parasite replication cycle. This free Hz is ingested by circulating and resident phagocytes. The presence of Hz in tissues after clearance of infection has been previously reported. Still, little is known about the kinetics of Hz in vivo, during and after Plasmodium infection. It is particularly important to understand Hz kinetics after malaria infections as it has been reported that Hz is associated with impairment of immune functions, including possible consequences for coinfections. Indeed, if Hz remains biologically active for prolonged periods of time inside immunocompetent cells, the potential consequences of such accumulation and presence to the immune system should be clarified. Here, using several independent methods to assess the presence of Hz, we report the long-term in vivo kinetics of Hz in diverse organs in a murine model of malaria infection.

  2. Examination on the protein profiles of salivary glands of P. berghei infected anopheles Sp. post gamma irradiation using SDS-PAGE technique for developing malaria vaccine

    International Nuclear Information System (INIS)

    Tetriana, D.; Syaifudin, M.

    2014-01-01

    Sporozoite is a step of malaria parasitic live cycle that is most invasive and appropriate vaccine candidate. Result of experiments showed that malaria vaccine created by attenuating Plasmodium sp sporozoites with gamma rays was proven more effective. Study on the effects of irradiation to the profiles of protein in vaccine development is also important. The aim of this research was to examine the protein profile of salivary glands in sporozoite infected Anopheles sp post gamma irradiation using Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) technique. Examination covered the infection of Anopheles sp with Plasmodium sp, maintenance of infected mosquitoes for 14-16 days to obtain sporozoites, in vivo - in vitro irradiation of mosquitoes, preparation of salivary glands, electrophoresis on 10% SDS-PAGE, and Commassie blue staining. Results showed a different protein profile of infected and non infected salivary glands of Anopheles sp. There was additional protein band numbers at higher dose of irradiation (200 Gy) from sporozoite protein of P. berghei (MW 62 kDa). However, no difference of the profiles of circumsporozoite protein (CSP) observed among gamma irradiation doses of 150, 175 and 200 Gy. These results provide basic information that would lead to further study on the role of sporozoite proteins in malaria vaccine development. (author)

  3. Enhanced antioxidant capacity following selenium supplemented antimalarial therapy in Plasmodium berghei infected mice

    Science.gov (United States)

    Adebayo, Abiodun Humphrey; Olasehinde, Grace Iyabo; Egbeola, Oluwaseun Ayodimeji; Yakubu, Omolara Faith; Adeyemi, Alaba Oladipupo; Adekeye, Bosede Temitope

    2018-04-01

    The effect of the co-administration of artemether, lumefantrine and selenium was studied in mice infected with Plasmodium bergheiparasite. The mice were divided into seven groups of six animals per group. All groups except A were parasitized. Group A (unparasitized/untreated) and B (parasitized/untreated) served as the positive and negative control respectively, these were administered with olive oil. Animals in groups C and D were treated with 8 and 48 mg/kg/bw of artemether and lumefantrine respectively while group E was treated with a combination of artemether and lumefantrine (8: 48 mg/kg/bw). Animals in group F were treated with 0.945 mg/kg/bw of selenium only and group G was treated with a combination of artemether, lumefantrine and selenium (8:48:0.945 mg/kg/bw). All the treatment was done for a three day period. These animals were subsequently anaesthetized and the organs were excised. Homogenates were prepared for aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total protein, reduced Glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) assays. The results showed a significant (pcells in group G when compared with group B. It may be concluded that the combination of artemether, lumefantrine and selenium showed a more potent effect against the parasite than the group treated with artemether and lumefantrine, thus, helps to combat post-infection oxidative stress in susceptible cells.

  4. Transmission blocking activity of a standardized neem (Azadirachta indica) seed extract on the rodent malaria parasite Plasmodium berghei in its vector Anopheles stephensi

    Science.gov (United States)

    2010-01-01

    Background The wide use of gametocytocidal artemisinin-based combination therapy (ACT) lead to a reduction of Plasmodium falciparum transmission in several African endemic settings. An increased impact on malaria burden may be achieved through the development of improved transmission-blocking formulations, including molecules complementing the gametocytocidal effects of artemisinin derivatives and/or acting on Plasmodium stages developing in the vector. Azadirachtin, a limonoid (tetranortriterpenoid) abundant in neem (Azadirachta indica, Meliaceae) seeds, is a promising candidate, inhibiting Plasmodium exflagellation in vitro at low concentrations. This work aimed at assessing the transmission-blocking potential of NeemAzal®, an azadirachtin-enriched extract of neem seeds, using the rodent malaria in vivo model Plasmodium berghei/Anopheles stephensi. Methods Anopheles stephensi females were offered a blood-meal on P. berghei infected, gametocytaemic BALB/c mice, treated intraperitoneally with NeemAzal, one hour before feeding. The transmission-blocking activity of the product was evaluated by assessing oocyst prevalence, oocyst density and capacity to infect healthy mice. To characterize the anti-plasmodial effects of NeemAzal® on early midgut stages, i.e. zygotes and ookinetes, Giemsa-stained mosquito midgut smears were examined. Results NeemAzal® completely blocked P. berghei development in the vector, at an azadirachtin dose of 50 mg/kg mouse body weight. The totally 138 examined, treated mosquitoes (three experimental replications) did not reveal any oocyst and none of the healthy mice exposed to their bites developed parasitaemia. The examination of midgut content smears revealed a reduced number of zygotes and post-zygotic forms and the absence of mature ookinetes in treated mosquitoes. Post-zygotic forms showed several morphological alterations, compatible with the hypothesis of an azadirachtin interference with the functionality of the microtubule

  5. Transmission blocking activity of a standardized neem (Azadirachta indica seed extract on the rodent malaria parasite Plasmodium berghei in its vector Anopheles stephensi

    Directory of Open Access Journals (Sweden)

    Esposito Fulvio

    2010-03-01

    Full Text Available Abstract Background The wide use of gametocytocidal artemisinin-based combination therapy (ACT lead to a reduction of Plasmodium falciparum transmission in several African endemic settings. An increased impact on malaria burden may be achieved through the development of improved transmission-blocking formulations, including molecules complementing the gametocytocidal effects of artemisinin derivatives and/or acting on Plasmodium stages developing in the vector. Azadirachtin, a limonoid (tetranortriterpenoid abundant in neem (Azadirachta indica, Meliaceae seeds, is a promising candidate, inhibiting Plasmodium exflagellation in vitro at low concentrations. This work aimed at assessing the transmission-blocking potential of NeemAzal®, an azadirachtin-enriched extract of neem seeds, using the rodent malaria in vivo model Plasmodium berghei/Anopheles stephensi. Methods Anopheles stephensi females were offered a blood-meal on P. berghei infected, gametocytaemic BALB/c mice, treated intraperitoneally with NeemAzal, one hour before feeding. The transmission-blocking activity of the product was evaluated by assessing oocyst prevalence, oocyst density and capacity to infect healthy mice. To characterize the anti-plasmodial effects of NeemAzal® on early midgut stages, i.e. zygotes and ookinetes, Giemsa-stained mosquito midgut smears were examined. Results NeemAzal® completely blocked P. berghei development in the vector, at an azadirachtin dose of 50 mg/kg mouse body weight. The totally 138 examined, treated mosquitoes (three experimental replications did not reveal any oocyst and none of the healthy mice exposed to their bites developed parasitaemia. The examination of midgut content smears revealed a reduced number of zygotes and post-zygotic forms and the absence of mature ookinetes in treated mosquitoes. Post-zygotic forms showed several morphological alterations, compatible with the hypothesis of an azadirachtin interference with the functionality

  6. Schizonticidal effect of a combination of Amaranthus spinosus L. and Andrographis paniculata Burm. f./Nees extracts in Plasmodium berghei-infected mice

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    Tiwuk Susantiningsih

    2012-05-01

    Full Text Available Background: Amaranthus spinosus and Andrographis paniculata are traditionally used as antimalarial herbs, but the combination of both has not yet been tested. The aim of this study was to determine the schizonticidal anti-malaria effect of a combination in Plasmodium berghei-infected mice.Methods: Male mice (Balb/c strain weighing 28-30 g, 7-8 weeks old, were randomly devided into 5 groups of 4 animals each. Group A: controls (nil and 4 treatment groups (B, C, D, and E. Group B: Amarathus 10 mg/kgBW, group C: Andrographis 2 mg/kgBW, group D: combination of Amaranthus + Andrographis 10 mg + 2 mg/kgBW. All treatment with plant extracts was administered orally, once per day for 7 days. Group E was given chloroquine 10 mg/kgBW, once a day orally, for 3 days.Results: The body weigh increased only in group D, hemoglobin concentration increased significantly vs controls (p < 0.05 in treatment groups C, D, and E, and blood schizonticidal activity was seen in all treatment groups, highest at almost 90% in groups D and E. Survival rate was 100% in all groups.Conclusion: The combination of Amaranthus and Andrographis (10 mg + 2 mg/kgBW exerts the same blood schizonticidal activity as chloroquine 10 mg/kgBW. (Med J Indones. 2012;21:66-70Keywords: Amaranthus spinosus, Andrographis paniculata, Balb/c mice, Plasmodium berghei, schizonticidal effect

  7. Immunization with a Circumsporozoite Epitope Fused to Bordetella pertussis Adenylate Cyclase in Conjunction with Cytotoxic T-Lymphocyte-Associated Antigen 4 Blockade Confers Protection against Plasmodium berghei Liver-Stage Malaria

    Czech Academy of Sciences Publication Activity Database

    Tartz, S.; Kamanová, Jana; Šimšová, Marcela; Šebo, Peter; Bolte, S.; Heussler, V.; Fleischer, B.; Jacobs, T.

    2006-01-01

    Roč. 74, č. 4 (2006), s. 2277-2285 ISSN 0019-9567 R&D Projects: GA AV ČR IBS5020311 Institutional research plan: CEZ:AV0Z50200510 Keywords : plasmodium berghei * immunity * malaria Subject RIV: EE - Microbiology, Virology Impact factor: 4.004, year: 2006

  8. Virus-Like Particle (VLP Plus Microcrystalline Tyrosine (MCT Adjuvants Enhance Vaccine Efficacy Improving T and B Cell Immunogenicity and Protection against Plasmodium berghei/vivax

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    Gustavo Cabral-Miranda

    2017-05-01

    Full Text Available Vaccination is the most effective prophylactic tool against infectious diseases. Despite continued efforts to control malaria, the disease still generally represents a significant unmet medical need. Microcrystalline tyrosine (MCT is a well described depot used in licensed allergy immunotherapy products and in clinical development. However, its proof of concept in prophylactic vaccines has only recently been explored. MCT has never been used in combination with virus-like particles (VLPs, which are considered to be one of the most potent inducers of cellular and humoral immune responses in mice and humans. In the current study we assessed the potential of MCT to serve as an adjuvant in the development of a vaccine against malaria either alone or combined with VLP using Plasmodium vivax thrombospondin-related adhesive protein (TRAP as a target antigen. We chemically coupled PvTRAP to VLPs derived from the cucumber mosaic virus fused to a universal T-cell epitope of the tetanus toxin (CMVtt, formulated with MCT and compared the induced immune responses to PvTRAP formulated in PBS or Alum. The protective capacity of the various formulations was assessed using Plasmodium berghei expressing PvTRAP. All vaccine formulations using adjuvants and/or VLP increased humoral immunogenicity for PvTRAP compared to the antigen alone. The most proficient responder was the group of mice immunized with the vaccine formulated with PvTRAP-VLP + MCT. The VLP-based vaccine formulated in MCT also induced the strongest T cell response and conferred best protection against challenge with recombinant Plasmodium berghei. Thus, the combination of VLP with MCT may take advantage of the properties of each component and appears to be an alternative biodegradable depot adjuvant for development of novel prophylactic vaccines.

  9. Plasmodium Cysteine Repeat Modular Proteins 3 and 4 are essential for malaria parasite transmission from the mosquito to the host

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    Mota Maria M

    2011-03-01

    Full Text Available Abstract Background The Plasmodium Cysteine Repeat Modular Proteins (PCRMP are a family of four conserved proteins of malaria parasites, that contain a number of motifs implicated in host-parasite interactions. Analysis of mutants of the rodent parasite Plasmodium berghei lacking expression of PCRMP1 or 2 showed that these proteins are essential for targeting of P. berghei sporozoites to the mosquito salivary gland and, hence, for transmission from the mosquito to the mouse. Methods In this work, the role of the remaining PCRMP family members, PCRMP3 and 4, has been investigated throughout the Plasmodium life cycle by generation and analysis of P. berghei gene deletion mutants, Δpcrmp3 and Δpcrmp4. The role of PCRMP members during the transmission and hepatic stages of the Plasmodium lifecycle has been evaluated by light- and electron microscopy and by analysis of liver stage development in HEPG2 cells in vitro and by infecting mice with mutant sporozoites. In addition, mice were immunized with live Δpcrmp3 and Δpcrmp4 sporozoites to evaluate their immunization potential as a genetically-attenuated parasite-based vaccine. Results Disruption of pcrmp3 and pcrmp4 in P. berghei revealed that they are also essential for transmission of the parasite through the mosquito vector, although acting in a distinct way to pbcrmp1 and 2. Mutants lacking expression of PCRMP3 or PCRMP4 show normal blood stage development and oocyst formation in the mosquito and develop into morphologically normal sporozoites, but these have a defect in egress from oocysts and do not enter the salivary glands. Sporozoites extracted from oocysts perform gliding motility and invade and infect hepatocytes but do not undergo further development and proliferation. Furthermore, the study shows that immunization with Δcrmp3 and Δcrmp4 sporozoites does not confer protective immunity upon subsequent challenge. Conclusions PCRMP3 and 4 play multiple roles during the Plasmodium life

  10. Vital and dispensable roles of Plasmodium multidrug resistance transporters during blood- and mosquito-stage development.

    Science.gov (United States)

    Rijpma, Sanna R; van der Velden, Maarten; Annoura, Takeshi; Matz, Joachim M; Kenthirapalan, Sanketha; Kooij, Taco W A; Matuschewski, Kai; van Gemert, Geert-Jan; van de Vegte-Bolmer, Marga; Siebelink-Stoter, Rianne; Graumans, Wouter; Ramesar, Jai; Klop, Onny; Russel, Frans G M; Sauerwein, Robert W; Janse, Chris J; Franke-Fayard, Blandine M; Koenderink, Jan B

    2016-07-01

    Multidrug resistance (MDR) proteins belong to the B subfamily of the ATP Binding Cassette (ABC) transporters, which export a wide range of compounds including pharmaceuticals. In this study, we used reverse genetics to study the role of all seven Plasmodium MDR proteins during the life cycle of malaria parasites. Four P. berghei genes (encoding MDR1, 4, 6 and 7) were refractory to deletion, indicating a vital role during blood stage multiplication and validating them as potential targets for antimalarial drugs. Mutants lacking expression of MDR2, MDR3 and MDR5 were generated in both P. berghei and P. falciparum, indicating a dispensable role for blood stage development. Whereas P. berghei mutants lacking MDR3 and MDR5 had a reduced blood stage multiplication in vivo, blood stage growth of P. falciparum mutants in vitro was not significantly different. Oocyst maturation and sporozoite formation in Plasmodium mutants lacking MDR2 or MDR5 was reduced. Sporozoites of these P. berghei mutants were capable of infecting mice and life cycle completion, indicating the absence of vital roles during liver stage development. Our results demonstrate vital and dispensable roles of MDR proteins during blood stages and an important function in sporogony for MDR2 and MDR5 in both Plasmodium species. © 2016 John Wiley & Sons Ltd.

  11. Translational Repression in Malaria Sporozoites

    Science.gov (United States)

    Turque, Oliver; Tsao, Tiffany; Li, Thomas; Zhang, Min

    2016-01-01

    Malaria is a mosquito-borne infectious disease of humans and other animals. It is caused by the parasitic protozoan, Plasmodium. Sporozoites, the infectious form of malaria parasites, are quiescent when they remain in the salivary glands of the Anopheles mosquito until transmission into a mammalian host. Metamorphosis of the dormant sporozoite to its active form in the liver stage requires transcriptional and translational regulations. Here, we summarize recent advances in the translational repression of gene expression in the malaria sporozoite. In sporozoites, many mRNAs that are required for liver stage development are translationally repressed. Phosphorylation of eukaryotic Initiation Factor 2α (eIF2α) leads to a global translational repression in sporozoites. The eIF2α kinase, known as Upregulated in Infectious Sporozoite 1 (UIS1), is dominant in the sporozoite. The eIF2α phosphatase, UIS2, is translationally repressed by the Pumilio protein Puf2. This translational repression is alleviated when sporozoites are delivered into the mammalian host. PMID:28357358

  12. Translational repression in malaria sporozoites

    Directory of Open Access Journals (Sweden)

    Oliver Turque

    2016-04-01

    Full Text Available Malaria is a mosquito-borne infectious disease of humans and other animals. It is caused by the parasitic protozoan, Plasmodium. Sporozoites, the infectious form of malaria parasites, are quiescent when they remain in the salivary glands of the Anopheles mosquito until transmission into a mammalian host. Metamorphosis of the dormant sporozoite to its active form in the liver stage requires transcriptional and translational regulations. Here, we summarize recent advances in the translational repression of gene expression in the malaria sporozoite. In sporozoites, many mRNAs that are required for liver stage development are translationally repressed. Phosphorylation of eukaryotic Initiation Factor 2α (eIF2α leads to a global translational repression in sporozoites. The eIF2α kinase, known as Upregulated in Infectious Sporozoite 1 (UIS1, is dominant in the sporozoite. The eIF2α phosphatase, UIS2, is translationally repressed by the Pumilio protein Puf2. This translational repression is alleviated when sporozoites are delivered into the mammalian host.

  13. An assessment in rodents of the pathological and immunopathological consequence of multiple vaccinations and challenge with radiation-attenuated malaria parasites (blood forms and sporozoites)

    International Nuclear Information System (INIS)

    Boonpucknavig, S.

    1982-06-01

    Multiple vaccination with irradiated merozoites of Plasmodium berghei resulted in high levels of circulating antibody but a low degree of protection to challenge with normal merozoites. On the other hand, the multiple vaccinations and the challenge resulted in severe immunopathological reactions shortly after the immunization or challenge. These reactions were seen in the liver, kidneys and spleen and included the accumulation of mononuclear cells, severe coagulative necrosis of liver cells and proliferative changes in the splenic white pulp and in the glomeruli. The pathological reactions were more severe than in non-immunized animals but the parasitemia was lower and less malarial antigen was detected in Kupfer Cells of the liver, the sinusoidal cells of the spleen and the reticuloendothelial cells in the interstitial tissue of the kidney. Vaccination with irradiated sporozoites of P. berghei resulted in good protection to challenge with normal sporozoites even before circulating anti-sporozoite antibody could be detected. Only mild pathological changes were associated with up to 4 immunizations followed by challenge and these were largely limited to the liver, and were reversible. Sporozoite antigens were detected in the spleen and immune complexes in the glomeruli for 2-4 weeks following challenge but not later. Immunized mice however often developed some lobular pneumonia of the lung but the severity of this did not increase with challenge

  14. Phenotypic dissection of a Plasmodium-refractory strain of malaria vector Anopheles stephensi: the reduced susceptibility to P. berghei and P. yoelii.

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    Naoaki Shinzawa

    Full Text Available Anopheline mosquitoes are the major vectors of human malaria. Parasite-mosquito interactions are a critical aspect of disease transmission and a potential target for malaria control. Current investigations into parasite-mosquito interactions frequently assume that genetically resistant and susceptible mosquitoes exist in nature. Therefore, comparisons between the Plasmodium susceptibility profiles of different mosquito species may contribute to a better understanding of vectorial capacity. Anopheles stephensi is an important malaria vector in central and southern Asia and is widely used as a laboratory model of parasite transmission due to its high susceptibility to Plasmodium infection. In the present study, we identified a rodent malaria-refractory strain of A. stephensi mysorensis (Ehime by comparative study of infection susceptibility. A very low number of oocysts develop in Ehime mosquitoes infected with P. berghei and P. yoelii, as determined by evaluation of developed oocysts on the basal lamina. A stage-specific study revealed that this reduced susceptibility was due to the impaired formation of ookinetes of both Plasmodium species in the midgut lumen and incomplete crossing of the midgut epithelium. There were no apparent abnormalities in the exflagellation of male parasites in the ingested blood or the maturation of oocysts after the rounding up of the ookinetes. Overall, these results suggest that invasive-stage parasites are eliminated in both the midgut lumen and epithelium in Ehime mosquitoes by strain-specific factors that remain unknown. The refractory strain newly identified in this report would be an excellent study system for investigations into novel parasite-mosquito interactions in the mosquito midgut.

  15. In vitro activity of wALADin benzimidazoles against different life cycle stages of Plasmodium parasites.

    Science.gov (United States)

    Lentz, Christian S; Sattler, Julia M; Fendler, Martina; Gottwalt, Simon; Halls, Victoria S; Strassel, Silke; Arriens, Sandra; Hannam, Jeffrey S; Specht, Sabine; Famulok, Michael; Mueller, Ann-Kristin; Hoerauf, Achim; Pfarr, Kenneth M

    2015-01-01

    wALADin1 benzimidazoles are specific inhibitors of δ-aminolevulinic acid dehydratase from Wolbachia endobacteria of filarial nematodes. We report that wALADin1 and two derivatives killed blood stage Plasmodium falciparum in vitro (50% inhibitory concentrations, 39, 7.7, and 12.8 μM, respectively). One of these derivatives inhibited gliding motility of Plasmodium berghei ANKA infectious sporozoites with nanomolar affinity and blocked invasion into hepatocytes but did not affect intrahepatocytic replication. Hence, wALADin1 benzimidazoles are tools to study gliding motility and potential antiplasmodial drug candidates. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  16. AKTIVITAS ANTIMALARIA (IN VIVO KOMBINASI BUAH SIRIH (Piper betle L, DAUN MIYANA (Plectranthus scutellarioides (L. R. BR. MADU DAN KUNING TELUR PADA MEN CIT YANG DIINFEKSI Plasmodium berghei

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    Yun Astuti Nugroho

    2012-07-01

    Full Text Available Malaria is a major public health problem in the world and developing countries in particular, causing an estimated 1-2 million deaths per year, an annual incidence of 300-500 million clinical cases and more than 2 billion people were at risk of infection from it. But it is also becoming more difficult to treat malaria due to the increasing drug resistance. Therefore, the need for alternative drugs is acute. This study aims at investigating the in vivo antiplasmodial activity of Piper betle L., fruit (buah sirih, Plectranthus scutellarioides (L. R. BR., (daun miyana, honey and egg yolk combination. Methods: A rodent malaria parasite, Plasmodium berghei, was inoculated into Swiss albino mice. The mice were infected with Ixl05 parasites intraperitoneally. The Piper betle L., fruit (buah sirih, Plectranthus scutellarioides (L. R. BR., (daun miyana, honey and egg yolk combination were combined and administered by an intra gastric tube daily for seven days starting from the day of parasite inoculation. The control groups received the same amount of solvent (vehicle used to suspend each dose of the herbal drug. Chloroquine was used as a standard drug, administered through the same route. Results: Combination of Piper betle L., fruit (buah sirih, Plectranthus scutellarioides (L. R. BR., (daun miyana, honey and egg yolk were observed to inhibit Plasomodium berghei parasitaemia in the Swiss albino mice 100 % on the sixth day. Conclusion: The study could partly confirm the claim in East Sulawesi traditional medicine that the Piper betle L., fruit (buah sirih, Plectranthus scutellarioides (L. R. BR., (daun miyana, honey and egg yolk combination has therapeutic values in human malaria. There was, thus, the need to initiate further in-depth investigation by using different experimental models.

  17. Critical role of a K+ channel in Plasmodium berghei transmission revealed by targeted gene disruption

    DEFF Research Database (Denmark)

    Ellekvist, Peter; Maciel, Jorge; Mlambo, Godfree

    2008-01-01

    through the mosquito vector remains unknown. We hypothesize that these two K(+) channels mediate the transport of K(+) in the parasites, and thus are important for parasite survival. To test this hypothesis, we identified the orthologue of one of the P. falciparum K(+) channels, PfKch1, in the rodent...... inhibition of the development of PbKch1-null parasites in Anopheles stephensi mosquitoes. In conclusion, these studies demonstrate that PbKch1 contributes to the transport of K(+) in P. berghei parasites and supports the growth of the parasites, in particular the development of oocysts in the mosquito midgut...

  18. Effects of Artemisin and Moringa oleifera Extract Combination on CD4+ and CD8+ Percentage of Mice Infected with Plasmodium berghei

    Directory of Open Access Journals (Sweden)

    Melda Fio Flora BR. Sijabat

    2016-11-01

    Full Text Available This research aims to examine the effect of Artemisin and Moringa oleifera leaf extract combination on the percentage of CD4+ and CD8+ T cell of mice infected with P.berghei. CD4+ and CD8+ T cells have important role in eliminating Plasmodium intracellular parasite that causes malaria infection. Artemisin is a potent antimalarial that kills the parasite through free radicals production. Excessive free radicals damage the immune cells, including CD4+ and CD8+ T cells. Flavonoid (quercetin and kaempferol bioactive on Moringa leaves is a powerful antioxidant and anti-inflammatory, and is expected to prevent and decrease the adverse effects of Artemisin. This experimental post-test group research was conducted on six groups, i.e. normal mice (negative control, P.berghei infected mice without treatment (positive control, and four other groups, i.e. P.berghei infected mice and treated with Artemisin 0.004mg/gBW (A, and combinations of Artemisin 0.004mg/gBW and Moringa leaf extract 0.125mg/gBW (DK1, 0.250mg/gBW (DK2, and 0.500mg/gBW (DK3. On day 3 and 7, blood samples from each group were drawn randomly, parasitemia degree was calculated microscopically (magnification 1000 times, the percentage of CD4+ and CD8+ T cells was determined using flowcytometry. The results of this study indicated that the administration of Artemisin and Moringa leaf extract combination for 7 days significant increased the percentage of CD4 + T cells in DK2 (p=0.001 and DK3 (p=0.000, and decreased the degree of parasitemia in DK1 (p=0.000, DK2 (p=0.000, and DK3 (p=0.000, however CD8 + T cells show no difference. There was a relationship between Artemisin and Moringa leaf extract combination with the degree of parasitemia (p=0.000 and the percentage of CD4+ T cells (p = 0.000, but not on CD8+ T cells.   Keywords: parasitemia, CD4+ and CD8+ T cells, Moringa oleifera

  19. Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes.

    Science.gov (United States)

    Roques, Magali; Wall, Richard J; Douglass, Alexander P; Ramaprasad, Abhinay; Ferguson, David J P; Kaindama, Mbinda L; Brusini, Lorenzo; Joshi, Nimitray; Rchiad, Zineb; Brady, Declan; Guttery, David S; Wheatley, Sally P; Yamano, Hiroyuki; Holder, Anthony A; Pain, Arnab; Wickstead, Bill; Tewari, Rita

    2015-11-01

    Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei.

  20. Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes

    KAUST Repository

    Roques, Magali; Wall, Richard J.; Douglass, Alexander P.; Ramaprasad, Abhinay; Ferguson, David J. P.; Kaindama, Mbinda L.; Brusini, Lorenzo; Joshi, Nimitray; Rchiad, ‍ Zineb; Brady, Declan; Guttery, David S.; Wheatley, Sally P.; Yamano, Hiroyuki; Holder, Anthony A.; Pain, Arnab; Wickstead, Bill; Tewari, Rita

    2015-01-01

    Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei.

  1. Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes

    KAUST Repository

    Roques, Magali

    2015-11-13

    Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei.

  2. Adenovirus Particles that Display the Plasmodium falciparum Circumsporozoite Protein NANP Repeat Induce Sporozoite-Neutralizing Antibodies in Mice

    OpenAIRE

    Palma, Christopher; Overstreet, Michael G.; Guedon, Jean-Marc; Hoiczyk, Egbert; Ward, Cameron; Karen, Kasey A.; Zavala, Fidel; Ketner, Gary

    2011-01-01

    Adenovirus particles can be engineered to display exogenous peptides on their surfaces by modification of viral capsid proteins, and particles that display pathogen-derived peptides can induce protective immunity. We constructed viable recombinant adenoviruses that display B-cell epitopes from the Plasmodium falciparum circumsporozoite protein (PfCSP) in the major adenovirus capsid protein, hexon. Recombinants induced high-titer antibodies against CSP when injected intraperitoneally into mice...

  3. Modification of oxidative status in Plasmodium berghei-infected erythrocytes by E-2-chloro-8-methyl-3-[(4'-methoxy-1'-indanoyl-2'-methyliden]-quinoline compared to chloroquine

    Directory of Open Access Journals (Sweden)

    Juan Rodrigues

    2009-09-01

    Full Text Available E-2-chloro-8-methyl-3-[(4'-methoxy-1'-indanoyl-2'-methyliden]-quinoline (IQ is a new quinoline derivative which has been reported as a haemoglobin degradation and ß-haematin formation inhibitor. The haemoglobin proteolysis induced by Plasmodium parasites represents a source of amino acids and haeme, leading to oxidative stress in infected cells. In this paper, we evaluated oxidative status in Plasmodium berghei-infected erythrocytes in the presence of IQ using chloroquine (CQ as a control. After haemolysis, superoxide dismutase (SOD, catalase, glutathione cycle and NADPH + H+-dependent dehydrogenase enzyme activities were investigated. Lipid peroxidation was also assayed to evaluate lipid damage. The results showed that the overall activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were significantly diminished by IQ (by 53.5% and 100%, respectively. Glutathione peroxidase activity was also lowered (31% in conjunction with a higher GSSG/GSH ratio. As a compensatory response, overall SOD activity increased and lipid peroxidation decreased, protecting the cells from the haemolysis caused by the infection. CQ shared most of the effects showed by IQ; however it was able to inhibit the activity of isocitrate dehydrogenase and glutathione-S-transferase. In conclusion, IQ could be a candidate for further studies in malaria research interfering with the oxidative status in Plasmodium berghei infection.

  4. Evaluating Controlled Human Malaria Infection in Kenyan Adults with Varying Degrees of Prior Exposure to Plasmodium falciparum using sporozoites administered by intramuscular injection

    Directory of Open Access Journals (Sweden)

    Susanne Helena Hodgson

    2014-12-01

    Full Text Available Background: Controlled human malaria infection (CHMI studies are a vital tool to accelerate vaccine and drug development. As CHMI trials are performed in a controlled environment, they allow unprecedented, detailed evaluation of parasite growth dynamics (PGD and immunological responses. However, CHMI studies have not been routinely performed in malaria-endemic countries or used to investigate mechanisms of naturally-acquired immunity (NAI to Plasmodium falciparum. Methods: We conducted an open-label, randomized CHMI pilot-study using aseptic, cryopreserved P. falciparum sporozoites (PfSPZ Challenge to evaluate safety, infectivity and PGD in Kenyan adults with low to moderate prior exposure to P. falciparum (Pan African Clinical Trial Registry: PACTR20121100033272. Results: All participants developed blood-stage infection confirmed by qPCR. However one volunteer (110 remained asymptomatic and blood-film negative until day 21 post-injection of PfSPZ Challenge. This volunteer had a reduced parasite multiplication rate (PMR (1.3 in comparison to the other 27 volunteers (median 11.1. A significant correlation was seen between PMR and screening anti-schizont ELISA OD (p=0.044, R=-0.384 but not when volunteer 110 was excluded from the analysis (p=0.112, R=-0.313. Conclusions: PfSPZ Challenge is safe and infectious in malaria-endemic populations and could be used to assess the efficacy of malaria vaccines and drugs in African populations. Whilst our findings are limited by sample size, our pilot study has demonstrated for the first time that NAI may impact on PMR post-CHMI in a detectable fashion, an important finding that should be evaluated in further CHMI studies.

  5. Teste de hemaglutinação na sorologia da malária humana empregando hemácias parasitadas pelo Plasmodium berghei

    Directory of Open Access Journals (Sweden)

    Maria Carmen Arroyo Sanchez-Ruiz

    1985-06-01

    Full Text Available Foi padronizado um teste de hemaglutinação para a sorologia da malária humana, com reagente constituído de suspensão de hemácias de camundongos infectadas pelo Plasmodium berghei e preservadas por fixação aldeídica. Em pacientes com parasitemia por P. falciparum ou P. vivax obteve-se uma sensibilidade de 98,9% nos 88 casos estudados, o teste apresentando títulos entre 40 e 640. Para o grupo de 476 soros de indivíduos não-maláricos, obteve-se uma especificidade de 96,0%. O teste apresentou elevada reprodutibilidade, mesmo para diferentes lotes de antígenos. Nos 200 soros, obtidos ao acaso, de indivíduos de área endêmica, o teste apresentou positividade de 48,5%, contra 88,0% do teste de imunofluorescência-IgG. A baixa positividade pode ser devida a que o teste de hemaglutinação detecta anticorpos IgM. Após tratamento com 2-mercaptoetanol, todos os soros de pacientes com parasitemia tornaram-se não reagentes. Em relação ao teste de imunofluorescência-IgG, o teste de hemaglutinação apresentou índice de co-positívidade de 0,989 para os soros de maláricos com parasitemia. Para os soros de não-maláricos o teste de hemaglutinação apresentou índice de co-negatividade de 0,969. Por outro lado, no grupo de soros de área endêmica, o índice de co-positividade foi de 0,528 e o de co-negatividade, de 0,833.A hemagglutination test is described for human malaria serodiagnosis with aldehyde-fixed Plasmodium berghei infected mouse erythrocytes. In patients with a P. falciparum or P. vivax patent parasitemia positive results were seen in 98.9% ofthe 88 cases tested. Titres rangedfrom 40 to 640. A 96.0% specificity wasfoundfor 476 non-malarialpatients. A close reproducibility was observed forthe test, even for dijferent reagent batches. The test was positive in 48.5% of 200 residents in malaria endemic areas, taken at random. These subjects showed 88.0% positivity of the IgG-immunofluorescence test. This lower positivity for

  6. Plasmodium berghei NK65 in Combination with IFN-γ Induces Endothelial Glucocorticoid Resistance via Sustained Activation of p38 and JNK

    Science.gov (United States)

    Zielińska, Karolina A.; de Cauwer, Lode; Knoops, Sofie; Van der Molen, Kristof; Sneyers, Alexander; Thommis, Jonathan; De Souza, J. Brian; Opdenakker, Ghislain; De Bosscher, Karolien; Van den Steen, Philippe E.

    2017-01-01

    Malaria-associated acute respiratory distress syndrome (MA-ARDS) is an often lethal complication of malaria. Currently, no adequate therapy for this syndrome exists. Although glucocorticoids (GCs) have been used to improve clinical outcome of ARDS, their therapeutic benefits remain unclear. We previously developed a mouse model of MA-ARDS, in which dexamethasone treatment revealed GC resistance. In the present study, we investigated GC sensitivity of mouse microvascular lung endothelial cells stimulated with interferon-γ (IFN-γ) and Plasmodium berghei NK65 (PbNK65). Upon challenge with IFN-γ alone, dexamethasone inhibited the expression of CCL5 (RANTES) by 90% and both CCL2 (MCP-1) and CXCL10 (IP-10) by 50%. Accordingly, whole transcriptome analysis revealed that dexamethasone differentially affected several gene clusters and in particular inhibited a large cluster of IFN-γ-induced genes, including chemokines. In contrast, combined stimulation with IFN-γ and PbNK65 extract impaired inhibitory actions of GCs on chemokine release, without affecting the capacity of the GC receptor to accumulate in the nucleus. Subsequently, we investigated the effects of GCs on two signaling pathways activated by IFN-γ. Dexamethasone left phosphorylation and protein levels of signal transducer and activator of transcription 1 (STAT1) unhampered. In contrast, dexamethasone inhibited the IFN-γ-induced activation of two mitogen-activated protein kinases (MAPK), JNK, and p38. However, PbNK65 extract abolished the inhibitory effects of GCs on MAPK signaling, inducing GC resistance. These data provide novel insights into the mechanisms of GC actions in endothelial cells and show how malaria may impair the beneficial effects of GCs. PMID:29033931

  7. Plasmodium berghei NK65 in Combination with IFN-γ Induces Endothelial Glucocorticoid Resistance via Sustained Activation of p38 and JNK

    Directory of Open Access Journals (Sweden)

    Karolina A. Zielińska

    2017-09-01

    Full Text Available Malaria-associated acute respiratory distress syndrome (MA-ARDS is an often lethal complication of malaria. Currently, no adequate therapy for this syndrome exists. Although glucocorticoids (GCs have been used to improve clinical outcome of ARDS, their therapeutic benefits remain unclear. We previously developed a mouse model of MA-ARDS, in which dexamethasone treatment revealed GC resistance. In the present study, we investigated GC sensitivity of mouse microvascular lung endothelial cells stimulated with interferon-γ (IFN-γ and Plasmodium berghei NK65 (PbNK65. Upon challenge with IFN-γ alone, dexamethasone inhibited the expression of CCL5 (RANTES by 90% and both CCL2 (MCP-1 and CXCL10 (IP-10 by 50%. Accordingly, whole transcriptome analysis revealed that dexamethasone differentially affected several gene clusters and in particular inhibited a large cluster of IFN-γ-induced genes, including chemokines. In contrast, combined stimulation with IFN-γ and PbNK65 extract impaired inhibitory actions of GCs on chemokine release, without affecting the capacity of the GC receptor to accumulate in the nucleus. Subsequently, we investigated the effects of GCs on two signaling pathways activated by IFN-γ. Dexamethasone left phosphorylation and protein levels of signal transducer and activator of transcription 1 (STAT1 unhampered. In contrast, dexamethasone inhibited the IFN-γ-induced activation of two mitogen-activated protein kinases (MAPK, JNK, and p38. However, PbNK65 extract abolished the inhibitory effects of GCs on MAPK signaling, inducing GC resistance. These data provide novel insights into the mechanisms of GC actions in endothelial cells and show how malaria may impair the beneficial effects of GCs.

  8. CD36 and Fyn kinase mediate malaria-induced lung endothelial barrier dysfunction in mice infected with Plasmodium berghei.

    Directory of Open Access Journals (Sweden)

    Ifeanyi U Anidi

    Full Text Available Severe malaria can trigger acute lung injury characterized by pulmonary edema resulting from increased endothelial permeability. However, the mechanism through which lung fluid conductance is altered during malaria remains unclear. To define the role that the scavenger receptor CD36 may play in mediating this response, C57BL/6J (WT and CD36-/- mice were infected with P. berghei ANKA and monitored for changes in pulmonary endothelial barrier function employing an isolated perfused lung system. WT lungs demonstrated a >10-fold increase in two measures of paracellular fluid conductance and a decrease in the albumin reflection coefficient (σalb compared to control lungs indicating a loss of barrier function. In contrast, malaria-infected CD36-/- mice had near normal fluid conductance but a similar reduction in σalb. In WT mice, lung sequestered iRBCs demonstrated production of reactive oxygen species (ROS. To determine whether knockout of CD36 could protect against ROS-induced endothelial barrier dysfunction, mouse lung microvascular endothelial monolayers (MLMVEC from WT and CD36-/- mice were exposed to H2O2. Unlike WT monolayers, which showed dose-dependent decreases in transendothelial electrical resistance (TER from H2O2 indicating loss of barrier function, CD36-/- MLMVEC demonstrated dose-dependent increases in TER. The differences between responses in WT and CD36-/- endothelial cells correlated with important differences in the intracellular compartmentalization of the CD36-associated Fyn kinase. Malaria infection increased total lung Fyn levels in CD36-/- lungs compared to WT, but this increase was due to elevated production of the inactive form of Fyn further suggesting a dysregulation of Fyn-mediated signaling. The importance of Fyn in CD36-dependent endothelial signaling was confirmed using in vitro Fyn knockdown as well as Fyn-/- mice, which were also protected from H2O2- and malaria-induced lung endothelial leak, respectively. Our

  9. IgG2 antibodies against a clinical grade Plasmodium falciparum CSP vaccine antigen associate with protection against transgenic sporozoite challenge in mice.

    Directory of Open Access Journals (Sweden)

    Robert Schwenk

    Full Text Available The availability of a highly purified and well characterized circumsporozoite protein (CSP is essential to improve upon the partial success of recombinant CSP-based malaria vaccine candidates. Soluble, near full-length, Plasmodium falciparum CSP vaccine antigen (CS/D was produced in E. coli under bio-production conditions that comply with current Good Manufacturing Practices (cGMP. A mouse immunogenicity study was conducted using a stable oil-in-water emulsion (SE of CS/D in combination with the Toll-Like Receptor 4 (TLR4 agonist Glucopyranosyl Lipid A (GLA/SE, or one of two TLR7/8 agonists: R848 (un-conjugated or 3M-051 (covalently conjugated. Compared to Alum and SE, GLA/SE induced higher CS/D specific antibody response in Balb/c mice. Subclass analysis showed higher IgG2:IgG1 ratio of GLA/SE induced antibodies as compared to Alum and SE. TLR synergy was not observed when soluble R848 was mixed with GLA/SE. Antibody response of 3M051 formulations in Balb/c was similar to GLA/SE, except for the higher IgG2:IgG1 ratio and a trend towards higher T cell responses in 3M051 containing groups. However, no synergistic enhancement of antibody and T cell response was evident when 3M051 conjugate was mixed with GLA/SE. In C57Bl/6 mice, CS/D adjuvanted with 3M051/SE or GLA/SE induced higher CSP repeat specific titers compared to SE. While, 3M051 induced antibodies had high IgG2c:IgG1 ratio, GLA/SE promoted high levels of both IgG1 and IgG2c. GLA/SE also induced more potent T-cell responses compared to SE in two independent C57/BL6 vaccination studies, suggesting a balanced and productive T(H1/T(H2 response. GLA and 3M-051 similarly enhanced the protective efficacy of CS/D against challenge with a transgenic P. berghei parasite and most importantly, high levels of cytophilic IgG2 antibodies were associated with protection in this model. Our data indicated that the cGMP-grade, soluble CS/D antigen combined with the TLR4-containing adjuvant GLA/SE warrants

  10. Rate of red blood cell destruction varies in different strains of mice infected with Plasmodium berghei-ANKA after chronic exposure

    Directory of Open Access Journals (Sweden)

    Kikuchi Mihoko

    2009-05-01

    Full Text Available Abstract Background Severe malaria anaemia in the semi-immune individuals in the holo-endemic area has been observed to occur at low parasite density with individual variation in the responses. Thus the following has been thought to be involved: auto-immune-mediated mechanisms of uninfected red blood cell destruction, and host genetic factors to explain the differences in individual responses under the same malaria transmission. In this study, the extent of red blood cell (RBC destruction in different strains of semi-immune mice model at relatively low parasitaemia was studied. Methodology To generate semi-immunity, four strains of mice were taken through several cycles of infection and treatment. By means of immunofluorescent assay and ELISA, sera were screened for anti-erythrocyte auto-antibodies, and their relationship with haematological parameters and parasitaemia in the strains of semi-immune mice was investigated. Results Upon challenge with Plasmodium berghei ANKA after generating semi-immune status, different mean percentage haemoglobin (Hb drop was observed in the mice strains (Balb/c = 47.1%; NZW = 30.05%; C57BL/6 = 28.44%; CBA = 25.1%, which occurred on different days for each strain (for Balb/c, mean period = 13.6 days; for C57BL/6, NZW, and CBA mean period = 10.6, 10.8, 10.9 days respectively. Binding of antibody to white ghost RBCs was observed in sera of the four strains of semi-immune mice by immunofluorescence. Mean percentage Hb drop per parasitaemia was highest in Balb/c (73.6, followed by C57BL/6 (8.6, CBA (6.9 and NZW (4.0, p = 0.0005. Consequently, auto-antibodies level to ghost RBC were correlated with degree of anaemia and were highest in Balb/c, when compared with the other strains, p Conclusion The results presented in this study seem to indicate that anti-RBC auto-antibodies may be involved in the destruction of uninfected RBC in semi-immune mice at relatively low parasite burden. Host genetic factors may also

  11. An analysis of the spatial distribution of Plasmodium sporozoites and effects of climatic correlates on malaria infection in Anyigba town, Nigeria.

    Science.gov (United States)

    Ifatimehin, Olarewaju Oluseyi; Falola, O O; Odogbo, E V

    2013-10-27

    The infectivity of sporozoites on both mosquitoes and human is the major cause of malaria infection on its host, Man. Malaria infection had continued to blossom despite measures to curb it. Clinically diagnosed malaria data for 3 years, capture of mosquitoes for laboratory analysis to determining the infectivity of sporozoites, responses from the population on the number of episode of malaria in the last 60 days were all collected and generated, and also subjected to various analysis using methods accepted tools and methods. A fifteen weeks climatic data was also collected. It was discovered that malaria incidence of 467.2853/1000 persons is very high. This high rate is possible as out of every 10 mosquitoes in Anyigba, 4 are infected by sporozoites and can possibly transmit these sporozoites during blood feeding on the population. This is affirmed by the prevalence of malaria by 54.75% among Anyigba's population. At p>001 (0.829), climatic variables and sporozoites rate showed a strong affinity with the prevalence of malaria. The risk map showed that the university community and the surrounding students' lodges are areas of very high risk. Therefore, the populace is strongly advised to employed practicable measures such as regular environmental sanitation and the use of Insecticidal Treated Nets (ITN) in order to drastically address this epidemic.

  12. Seroprevalence of Antibodies against Plasmodium falciparum Sporozoite Antigens as Predictive Disease Transmission Markers in an Area of Ghana with Seasonal Malaria Transmission.

    Directory of Open Access Journals (Sweden)

    Kwadwo A Kusi

    Full Text Available As an increasing number of malaria-endemic countries approach the disease elimination phase, sustenance of control efforts and effective monitoring are necessary to ensure success. Mathematical models that estimate anti-parasite antibody seroconversion rates are gaining relevance as more sensitive transmission intensity estimation tools. Models however estimate yearly seroconversion and seroreversion rates and usually predict long term changes in transmission, occurring years before the time of sampling. Another challenge is the identification of appropriate antigen targets since specific antibody levels must directly reflect changes in transmission patterns. We therefore investigated the potential of antibodies to sporozoite and blood stage antigens for detecting short term differences in malaria transmission in two communities in Northern Ghana with marked, seasonal transmission.Cross-sectional surveys were conducted during the rainy and dry seasons in two communities, one in close proximity to an irrigation dam and the other at least 20 Km away from the dam. Antibodies against the sporozoite-specific antigens circumsporozoite protein (CSP and Cell traversal for ookinetes and sporozoites (CelTOS and the classical blood stage antigen apical membrane antigen 1 (AMA1 were measured by indirect ELISA. Antibody levels and seroprevalence were compared between surveys and between study communities. Antibody seroprevalence data were fitted to a modified reversible catalytic model to estimate the seroconversion and seroreversion rates.Changes in sporozoite-specific antibody levels and seroprevalence directly reflected differences in parasite prevalence between the rainy and dry seasons and hence the extent of malaria transmission. Seroconversion rate estimates from modelled seroprevalence data did not however support the above observation.The data confirms the potential utility of sporozoite-specific antigens as useful markers for monitoring short term

  13. Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes

    Science.gov (United States)

    Ferguson, David J. P.; Kaindama, Mbinda L.; Brusini, Lorenzo; Joshi, Nimitray; Rchiad, Zineb; Brady, Declan; Guttery, David S.; Wheatley, Sally P.; Yamano, Hiroyuki; Holder, Anthony A.; Pain, Arnab; Wickstead, Bill; Tewari, Rita

    2015-01-01

    Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei. PMID:26565797

  14. In-Silico detection of chokepoints enzymes in four plasmodium species

    African Journals Online (AJOL)

    Of the over 156 species of Plasmodium that infect vertebrates, only four infect man: Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale and Plasmodium malariae. Other species infect other animals including birds, reptiles and rodents. The rodent malaria parasites are Plasmodium berghei, Plasmodium yoelii, ...

  15. First field trial of an immunoradiometric assay for the detection of malaria sporozoites in mosquitoes

    International Nuclear Information System (INIS)

    Collins, F.H.; Zavala, F.; Graves, P.M.; Cochrane, A.H.; Gwadz, R.W.; Akoh, J.; Nussenzweig, R.S.

    1984-01-01

    An immunoradiometric assay (IRMA) using a monoclonal antibody to the major surface protein of Plasmodium falciparum sporozoites was used to assess the P. falciparum sporozoite rate in a West African population of Anopheles gambiae (s.1.). Unlike current dissection techniques, the IRMA could detect sporozoite antigen in dried as well as fresh mosquitoes. In a controlled comparison, the sensitivity of the IRMA was comparable that of the dissection technique. Additionally, the IRMA was species specific and quantitative. Sensitivity of the assay was sufficient to detect sporozoite infections resulting from the development of a single oocyst

  16. Transgenic Parasites Stably Expressing Full-Length Plasmodium falciparum Circumsporozoite Protein as a Model for Vaccine Down-Selection in Mice Using Sterile Protection as an Endpoint

    Science.gov (United States)

    Porter, Michael D.; Nicki, Jennifer; Pool, Christopher D.; DeBot, Margot; Illam, Ratish M.; Brando, Clara; Bozick, Brooke; De La Vega, Patricia; Angra, Divya; Spaccapelo, Roberta; Crisanti, Andrea; Murphy, Jittawadee R.; Bennett, Jason W.; Schwenk, Robert J.; Ockenhouse, Christian F.

    2013-01-01

    Circumsporozoite protein (CSP) of Plasmodium falciparum is a protective human malaria vaccine candidate. There is an urgent need for models that can rapidly down-select novel CSP-based vaccine candidates. In the present study, the mouse-mosquito transmission cycle of a transgenic Plasmodium berghei malaria parasite stably expressing a functional full-length P. falciparum CSP was optimized to consistently produce infective sporozoites for protection studies. A minimal sporozoite challenge dose was established, and protection was defined as the absence of blood-stage parasites 14 days after intravenous challenge. The specificity of protection was confirmed by vaccinating mice with multiple CSP constructs of differing lengths and compositions. Constructs that induced high NANP repeat-specific antibody titers in enzyme-linked immunosorbent assays were protective, and the degree of protection was dependent on the antigen dose. There was a positive correlation between antibody avidity and protection. The antibodies in the protected mice recognized the native CSP on the parasites and showed sporozoite invasion inhibitory activity. Passive transfer of anti-CSP antibodies into naive mice also induced protection. Thus, we have demonstrated the utility of a mouse efficacy model to down-select human CSP-based vaccine formulations. PMID:23536694

  17. The systematic functional analysis of plasmodium protein kinases identifies essential regulators of mosquito transmission

    KAUST Repository

    Tewari, Rita; Straschil, Ursula; Bateman, Alex; Bö hme, Ulrike; Cherevach, Inna; Gong, Peng; Pain, Arnab; Billker, Oliver

    2010-01-01

    Although eukaryotic protein kinases (ePKs) contribute to many cellular processes, only three Plasmodium falciparum ePKs have thus far been identified as essential for parasite asexual blood stage development. To identify pathways essential for parasite transmission between their mammalian host and mosquito vector, we undertook a systematic functional analysis of ePKs in the genetically tractable rodent parasite Plasmodium berghei. Modeling domain signatures of conventional ePKs identified 66 putative Plasmodium ePKs. Kinomes are highly conserved between Plasmodium species. Using reverse genetics, we show that 23 ePKs are redundant for asexual erythrocytic parasite development in mice. Phenotyping mutants at four life cycle stages in Anopheles stephensi mosquitoes revealed functional clusters of kinases required for sexual development and sporogony. Roles for a putative SR protein kinase (SRPK) in microgamete formation, a conserved regulator of clathrin uncoating (GAK) in ookinete formation, and a likely regulator of energy metabolism (SNF1/KIN) in sporozoite development were identified. 2010 Elsevier Inc.

  18. The systematic functional analysis of plasmodium protein kinases identifies essential regulators of mosquito transmission

    KAUST Repository

    Tewari, Rita

    2010-10-21

    Although eukaryotic protein kinases (ePKs) contribute to many cellular processes, only three Plasmodium falciparum ePKs have thus far been identified as essential for parasite asexual blood stage development. To identify pathways essential for parasite transmission between their mammalian host and mosquito vector, we undertook a systematic functional analysis of ePKs in the genetically tractable rodent parasite Plasmodium berghei. Modeling domain signatures of conventional ePKs identified 66 putative Plasmodium ePKs. Kinomes are highly conserved between Plasmodium species. Using reverse genetics, we show that 23 ePKs are redundant for asexual erythrocytic parasite development in mice. Phenotyping mutants at four life cycle stages in Anopheles stephensi mosquitoes revealed functional clusters of kinases required for sexual development and sporogony. Roles for a putative SR protein kinase (SRPK) in microgamete formation, a conserved regulator of clathrin uncoating (GAK) in ookinete formation, and a likely regulator of energy metabolism (SNF1/KIN) in sporozoite development were identified. 2010 Elsevier Inc.

  19. A specific PfEMP1 is expressed in P. falciparum sporozoites and plays a role in hepatocyte infection

    DEFF Research Database (Denmark)

    Zanghì, Gigliola; Vembar, Shruthi S; Baumgarten, Sebastian

    2018-01-01

    Heterochromatin plays a central role in the process of immune evasion, pathogenesis, and transmission of the malaria parasite Plasmodium falciparum during blood stage infection. Here, we use ChIP sequencing to demonstrate that sporozoites from mosquito salivary glands expand heterochromatin......_SpzPfEMP1. Overall, we show that the epigenetic signature of var genes is reset in mosquito stages. Moreover, the identification of a strain-specific sporozoite PfEMP1 is highly relevant for vaccine design based on sporozoites....

  20. Immunity to sporozoite-induced malaria infection in mice. I. The effect of immunization of T and B cell-deficient mice

    International Nuclear Information System (INIS)

    Chen, D.H.; Tigelaar, R.E.; Weinbaum, F.I.

    1977-01-01

    The cellular basis of immunity to sporozoites was investigated by examining the effect of immunization of T and B cell-deficient C57BL/6N x BALB/c AnN F 1 (BLCF 1 ) mice compared to immunocompetent controls. Immunization of T cell-deficient (ATX-BM-ATS) BLCF 1 mice with x-irradiated sporozoites did not result in the generation of protective immunity. The same immunization protocols protected all immunocompetent controls. In contrast, B cell-deficient (μ-suppressed) BLCF 1 mice were protected by immunization in the majority of cases. The absence of detectable serum circumsporozoite precipitins or sporozoite neutralizing activity in the μ-suppressed mice that resisted a sporozoite challenge suggests a minor role for these humoral factors in protection. These data demonstrate a preeminent role for T cells in the induction of protective immunity in BLCF 1 mice against a P. berghei sporozoite infection

  1. Genome-wide RIP-Chip analysis of translational repressor-bound mRNAs in the Plasmodium gametocyte

    KAUST Repository

    Guerreiro, Ana

    2014-11-03

    Background Following fertilization, the early proteomes of metazoans are defined by the translation of stored but repressed transcripts; further embryonic development relies on de novo transcription of the zygotic genome. During sexual development of Plasmodium berghei, a rodent model for human malaria species including P. falciparum, the stability of repressed mRNAs requires the translational repressors DOZI and CITH. When these repressors are absent, Plasmodium zygote development and transmission to the mosquito vector is halted, as hundreds of transcripts become destabilized. However, which mRNAs are direct targets of these RNA binding proteins, and thus subject to translational repression, is unknown. Results We identify the maternal mRNA contribution to post-fertilization development of P. berghei using RNA immunoprecipitation and microarray analysis. We find that 731 mRNAs, approximately 50% of the transcriptome, are associated with DOZI and CITH, allowing zygote development to proceed in the absence of RNA polymerase II transcription. Using GFP-tagging, we validate the repression phenotype of selected genes and identify mRNAs relying on the 5′ untranslated region for translational control. Gene deletion reveals a novel protein located in the ookinete crystalloid with an essential function for sporozoite development. Conclusions Our study details for the first time the P. berghei maternal repressome. This mRNA population provides the developing ookinete with coding potential for key molecules required for life-cycle progression, and that are likely to be critical for the transmission of the malaria parasite from the rodent and the human host to the mosquito vector.

  2. SAS6-like protein in Plasmodium indicates that conoid-associated apical complex proteins persist in invasive stages within the mosquito vector.

    Science.gov (United States)

    Wall, Richard J; Roques, Magali; Katris, Nicholas J; Koreny, Ludek; Stanway, Rebecca R; Brady, Declan; Waller, Ross F; Tewari, Rita

    2016-06-24

    The SAS6-like (SAS6L) protein, a truncated paralogue of the ubiquitous basal body/centriole protein SAS6, has been characterised recently as a flagellum protein in trypanosomatids, but associated with the conoid in apicomplexan Toxoplasma. The conoid has been suggested to derive from flagella parts, but is thought to have been lost from some apicomplexans including the malaria-causing genus Plasmodium. Presence of SAS6L in Plasmodium, therefore, suggested a possible role in flagella assembly in male gametes, the only flagellated stage. Here, we have studied the expression and role of SAS6L throughout the Plasmodium life cycle using the rodent malaria model P. berghei. Contrary to a hypothesised role in flagella, SAS6L was absent during gamete flagellum formation. Instead, SAS6L was restricted to the apical complex in ookinetes and sporozoites, the extracellular invasive stages that develop within the mosquito vector. In these stages SAS6L forms an apical ring, as we show is also the case in Toxoplasma tachyzoites. The SAS6L ring was not apparent in blood-stage invasive merozoites, indicating that the apical complex is differentiated between the different invasive forms. Overall this study indicates that a conoid-associated apical complex protein and ring structure is persistent in Plasmodium in a stage-specific manner.

  3. P. berghei telomerase subunit TERT is essential for parasite survival.

    Directory of Open Access Journals (Sweden)

    Agnieszka A Religa

    Full Text Available Telomeres define the ends of chromosomes protecting eukaryotic cells from chromosome instability and eventual cell death. The complex regulation of telomeres involves various proteins including telomerase, which is a specialized ribonucleoprotein responsible for telomere maintenance. Telomeres of chromosomes of malaria parasites are kept at a constant length during blood stage proliferation. The 7-bp telomere repeat sequence is universal across different Plasmodium species (GGGTTT/CA, though the average telomere length varies. The catalytic subunit of telomerase, telomerase reverse transcriptase (TERT, is present in all sequenced Plasmodium species and is approximately three times larger than other eukaryotic TERTs. The Plasmodium RNA component of TERT has recently been identified in silico. A strategy to delete the gene encoding TERT via double cross-over (DXO homologous recombination was undertaken to study the telomerase function in P. berghei. Expression of both TERT and the RNA component (TR in P. berghei blood stages was analysed by Western blotting and Northern analysis. Average telomere length was measured in several Plasmodium species using Telomere Restriction Fragment (TRF analysis. TERT and TR were detected in blood stages and an average telomere length of ∼ 950 bp established. Deletion of the tert gene was performed using standard transfection methodologies and we show the presence of tert- mutants in the transfected parasite populations. Cloning of tert- mutants has been attempted multiple times without success. Thorough analysis of the transfected parasite populations and the parasite obtained from extensive parasite cloning from these populations provide evidence for a so called delayed death phenotype as observed in different organisms lacking TERT. The findings indicate that TERT is essential for P. berghei cell survival. The study extends our current knowledge on telomere biology in malaria parasites and validates further

  4. Plasmodium cysteine repeat modular proteins 1-4: complex proteins with roles throughout the malaria parasite life cycle.

    Science.gov (United States)

    Thompson, Joanne; Fernandez-Reyes, Delmiro; Sharling, Lisa; Moore, Sally G; Eling, Wijnand M; Kyes, Sue A; Newbold, Christopher I; Kafatos, Fotis C; Janse, Chris J; Waters, Andrew P

    2007-06-01

    The Cysteine Repeat Modular Proteins (PCRMP1-4) of Plasmodium, are encoded by a small gene family that is conserved in malaria and other Apicomplexan parasites. They are very large, predicted surface proteins with multipass transmembrane domains containing motifs that are conserved within families of cysteine-rich, predicted surface proteins in a range of unicellular eukaryotes, and a unique combination of protein-binding motifs, including a >100 kDa cysteine-rich modular region, an epidermal growth factor-like domain and a Kringle domain. PCRMP1 and 2 are expressed in life cycle stages in both the mosquito and vertebrate. They colocalize with PfEMP1 (P. falciparum Erythrocyte Membrane Antigen-1) during its export from P. falciparum blood-stage parasites and are exposed on the surface of haemolymph- and salivary gland-sporozoites in the mosquito, consistent with a role in host tissue targeting and invasion. Gene disruption of pcrmp1 and 2 in the rodent malaria model, P. berghei, demonstrated that both are essential for transmission of the parasite from the mosquito to the mouse and has established their discrete and important roles in sporozoite targeting to the mosquito salivary gland. The unprecedented expression pattern and structural features of the PCRMPs thus suggest a variety of roles mediating host-parasite interactions throughout the parasite life cycle.

  5. Vaccine Containing the Three Allelic Variants of the Plasmodium vivax Circumsporozoite Antigen Induces Protection in Mice after Challenge with a Transgenic Rodent Malaria Parasite

    Directory of Open Access Journals (Sweden)

    Alba Marina Gimenez

    2017-10-01

    Full Text Available Plasmodium vivax is the most common species that cause malaria outside of the African continent. The development of an efficacious vaccine would contribute greatly to control malaria. Recently, using bacterial and adenoviral recombinant proteins based on the P. vivax circumsporozoite protein (CSP, we demonstrated the possibility of eliciting strong antibody-mediated immune responses to each of the three allelic forms of P. vivax CSP (PvCSP. In the present study, recombinant proteins representing the PvCSP alleles (VK210, VK247, and P. vivax-like, as well as a hybrid polypeptide, named PvCSP-All epitopes, were generated. This hybrid containing the conserved C-terminal of the PvCSP and the three variant repeat domains in tandem were successfully produced in the yeast Pichia pastoris. After purification and biochemical characterization, they were used for the experimental immunization of C57BL/6 mice in a vaccine formulation containing the adjuvant Poly(I:C. Immunization with a recombinant protein expressing all three different allelic forms in fusion elicited high IgG antibody titers reacting with all three different allelic variants of PvCSP. The antibodies targeted both the C-terminal and repeat domains of PvCSP and recognized the native protein on the surface of P. vivax sporozoites. More importantly, mice that received the vaccine formulation were protected after challenge with chimeric Plasmodium berghei sporozoites expressing CSP repeats of P. vivax sporozoites (Pb/PvVK210. Our results suggest that it is possible to elicit protective immunity against one of the most common PvCSP alleles using soluble recombinant proteins expressed by P. pastoris. These recombinant proteins are promising candidates for clinical trials aiming to develop a multiallele vaccine against P. vivax malaria.

  6. Controlled human malaria infection by intramuscular and direct venous inoculation of cryopreserved Plasmodium falciparum sporozoites in malaria-naïve volunteers: effect of injection volume and dose on infectivity rates

    NARCIS (Netherlands)

    Gómez-Pérez, Gloria P.; Legarda, Almudena; Muñoz, Jose; Sim, B. Kim Lee; Ballester, María Rosa; Dobaño, Carlota; Moncunill, Gemma; Campo, Joseph J.; Cisteró, Pau; Jimenez, Alfons; Barrios, Diana; Mordmüller, Benjamin; Pardos, Josefina; Navarro, Mireia; Zita, Cecilia Justino; Nhamuave, Carlos Arlindo; García-Basteiro, Alberto L.; Sanz, Ariadna; Aldea, Marta; Manoj, Anita; Gunasekera, Anusha; Billingsley, Peter F.; Aponte, John J.; James, Eric R.; Guinovart, Caterina; Antonijoan, Rosa M.; Kremsner, Peter G.; Hoffman, Stephen L.; Alonso, Pedro L.

    2015-01-01

    Controlled human malaria infection (CHMI) by mosquito bite is a powerful tool for evaluation of vaccines and drugs against Plasmodium falciparum malaria. However, only a small number of research centres have the facilities required to perform such studies. CHMI by needle and syringe could help to

  7. Functional Identification of the Plasmodium Centromere and Generation of a Plasmodium Artificial Chromosome

    OpenAIRE

    Iwanaga, Shiroh; Khan, Shahid M.; Kaneko, Izumi; Christodoulou, Zoe; Newbold, Chris; Yuda, Masao; Janse, Chris J.; Waters, Andrew P.

    2010-01-01

    Summary The artificial chromosome represents a useful tool for gene transfer, both as cloning vectors and in chromosome biology research. To generate a Plasmodium artificial chromosome (PAC), we had to first functionally identify and characterize the parasite's centromere. A putative centromere (pbcen5) was cloned from chromosome 5 of the rodent parasite P. berghei based on a Plasmodium gene-synteny map. Plasmids containing pbcen5 were stably maintained in parasites during a blood-stage infec...

  8. Self-assembling protein nanoparticles with built-in flagellin domains increases protective efficacy of a Plasmodium falciparum based vaccine.

    Science.gov (United States)

    Kaba, Stephen A; Karch, Christopher P; Seth, Labdhi; Ferlez, Karen M B; Storme, Casey K; Pesavento, Danielle M; Laughlin, Paige Y; Bergmann-Leitner, Elke S; Burkhard, Peter; Lanar, David E

    2018-02-01

    To eliminate the problems associated with the use of extraneous adjuvants we have designed a Self-Assembling Protein Nanoparticle (SAPN) containing epitopes from the Plasmodium falciparum circumsporozoite protein (PfCSP) (designated FMP014) and portions of the TLR5 agonist flagellin (designated FMP014 D0D1 ) as an intrinsic adjuvant. By combining different molar ratios of FMP014 to FMP014 D0D1 monomers before self-assembly, we generated multiple nanoparticles and investigated their biophysical characteristics, immunogenicity and protective efficacy. Immunization with the construct formulated with the ratio 58:2 of FMP014 to FMP014 D0D1 had the highest protective efficacy against a challenge with a transgenic P. berghei sporozoite expressing PfCSP. Increasing the proportion of flagellin per particle resulted in an inverse relationship with levels of both antibody titers and protection. The cytokine profiles of the various immunization groups were evaluated and quantitative amounts of the cytokines IL-2, IFN-γ, IL-12/p70 (Th1); IL4, IL5 (Th2); TNF-α, IL1β, IL-6, KC/GRO (pro-inflammatory), and IL-10 (immunomodulatory) were measured. The relationship of the cytokines to each other revealed a strong immunomodulatory effect depending on the proportion of flagellin in the construct. Our results demonstrate that SAPNs with flagellin may be a promising strategy for the development and delivery of a safe vaccine for infectious diseases. Published by Elsevier Ltd.

  9. THE SPOROZOITE ENZYME-LINKED IMMUNOSORBENT ASSAY : APPLICATION IN MALARIA EPIDEMIOLOGY

    Directory of Open Access Journals (Sweden)

    Michael J. Bangs

    2012-09-01

    Full Text Available Recent biotechnological breakthroughs have led to the development of various methods for detection and identification of human pathogens in their vectors. Monoclonal antibodies produced against malaria sporozoite antigens have permitted the development of several sensitive, species specific immunological tests (IFA, IRMA, ELIS A. One of these, a two-site enzyme-linked immunosorbent assay (ELIS A has been developed as a useful epidemiological tool in the identification of malaria-infected mosquitoes. This method employs highly species specific monoclonal antibodies that recognize the repetitive immunodominant epitope of the circumsporozoite (CS protein. Monoclonal antibodies have been developed for all four species of human malaria The key feature of the ELISA technique is the use of an enzyme indicator for an immunological reaction. The antigen capture or "sandwich" ELISA configuration uses the purified monoclonal both as the solid phase and, conjugated to enzyme, as a marker for the presence of CS protein in a mosquito homogenate incubated in the wells of a microtitration plate. This technology has shown advantages over other methods for epidemiological data collection. Mosquitoes can be caught, dried and stored until a time convenient for examination. The sporozoite rate by Plasmodium species can be identified easily, and when combined with the man-biting rate provides the sporozoite inoculation rate, an important entomologic estimate of the number of potential infective bites a person could expect over a given period of time. Presently, mosquitoes can be tested individually or pooled up to 20 anophe lines. The assay is sensitive enough to detect 1 infected mosquito per pool or as few as 25 sporozoites per 50 pi of mosquito extract. Basic principles and procedures are covered concerning solid substrate, adsorption to solid substrate, buffers and wash solutions, conjugates and enzyme substrates. The advantages and limitations of this technique

  10. The rhoptry proteome of Eimeria tenella sporozoites

    KAUST Repository

    Oakes, Richard D.; Kurian, Dominic; Bromley, Elizabeth V.; Ward, Chris; Lal, Kalpana; Blake, Damer P.; Reid, Adam James; Pain, Arnab; Sinden, Robert E.; Wastling, Jonathan M.; Tomley, F. M. M Fiona

    2013-01-01

    Proteins derived from the rhoptry secretory organelles are crucial for the invasion and survival of apicomplexan parasites within host cells. The rhoptries are club-shaped organelles that contain two distinct subpopulations of proteins that localise to separate compartments of the organelle. Proteins from the neck region (rhoptry neck proteins, RON) are secreted early in invasion and a subset of these is critical for the formation and function of the moving junction between parasite and host membranes. Proteins from the bulb compartment (rhoptry protein, ROP) are released later, into the nascent parasitophorous vacuole where they have a role in modifying the vacuolar environment, and into the host cell where they act as key determinants of virulence through their ability to interact with host cell signalling pathways, causing an array of downstream effects. In this paper we present the results of an extensive proteomics analysis of the rhoptry organelles from the coccidian parasite, Eimeria tenella, which is a highly pathogenic parasite of the domestic chicken causing severe caecal coccidiosis. Several different classes of rhoptry protein have been identified. First are the RON proteins that have varying degrees of similarity to proteins of Toxoplasma gondii and Neospora caninum. For some RON families, E. tenella expresses more than one gene product and many of the individual RON proteins are differentially expressed between the sporozoite and merozoite developmental stages. The E. tenella sporozoite rhoptry expresses only a limited repertoire of proteins with homology to known ROP proteins from other coccidia, including just two secreted ROP kinases, both of which appear to be equipped for catalytic activity. Finally, a large number of hitherto undescribed proteins that map to the sporozoite rhoptry are identified, many of which have orthologous proteins encoded within the genomes of T. gondii and N. caninum. © 2012 .

  11. The rhoptry proteome of Eimeria tenella sporozoites

    KAUST Repository

    Oakes, Richard D.

    2013-02-01

    Proteins derived from the rhoptry secretory organelles are crucial for the invasion and survival of apicomplexan parasites within host cells. The rhoptries are club-shaped organelles that contain two distinct subpopulations of proteins that localise to separate compartments of the organelle. Proteins from the neck region (rhoptry neck proteins, RON) are secreted early in invasion and a subset of these is critical for the formation and function of the moving junction between parasite and host membranes. Proteins from the bulb compartment (rhoptry protein, ROP) are released later, into the nascent parasitophorous vacuole where they have a role in modifying the vacuolar environment, and into the host cell where they act as key determinants of virulence through their ability to interact with host cell signalling pathways, causing an array of downstream effects. In this paper we present the results of an extensive proteomics analysis of the rhoptry organelles from the coccidian parasite, Eimeria tenella, which is a highly pathogenic parasite of the domestic chicken causing severe caecal coccidiosis. Several different classes of rhoptry protein have been identified. First are the RON proteins that have varying degrees of similarity to proteins of Toxoplasma gondii and Neospora caninum. For some RON families, E. tenella expresses more than one gene product and many of the individual RON proteins are differentially expressed between the sporozoite and merozoite developmental stages. The E. tenella sporozoite rhoptry expresses only a limited repertoire of proteins with homology to known ROP proteins from other coccidia, including just two secreted ROP kinases, both of which appear to be equipped for catalytic activity. Finally, a large number of hitherto undescribed proteins that map to the sporozoite rhoptry are identified, many of which have orthologous proteins encoded within the genomes of T. gondii and N. caninum. © 2012 .

  12. The role of cGMP signalling in regulating life cycle progression of Plasmodium.

    OpenAIRE

    Hopp, CS; Bowyer, PW; Baker, DA

    2012-01-01

    The 3′-5′-cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG) is the main mediator of cGMP signalling in the malaria parasite. This article reviews the role of PKG in Plasmodium falciparum during gametogenesis and blood stage schizont rupture, as well as the role of the Plasmodium berghei orthologue in ookinete differentiation and motility, and liver stage schizont development. The current views on potential effector proteins downstream of PKG and the mechanisms that may regu...

  13. A full-length Plasmodium falciparum recombinant circumsporozoite protein expressed by Pseudomonas fluorescens platform as a malaria vaccine candidate.

    Directory of Open Access Journals (Sweden)

    Amy R Noe

    Full Text Available The circumsporozoite protein (CSP of Plasmodium falciparum is a major surface protein, which forms a dense coat on the sporozoite's surface. Preclinical research on CSP and clinical evaluation of a CSP fragment-based RTS, S/AS01 vaccine have demonstrated a modest degree of protection against P. falciparum, mediated in part by humoral immunity and in part by cell-mediated immunity. Given the partial protective efficacy of the RTS, S/AS01 vaccine in a recent Phase 3 trial, further improvement of CSP-based vaccines is crucial. In this report, we describe the preclinical development of a full-length, recombinant CSP (rCSP-based vaccine candidate against P. falciparum malaria suitable for current Good Manufacturing Practice (cGMP production. Utilizing a novel high-throughput Pseudomonas fluorescens expression platform, we demonstrated greater efficacy of full-length rCSP as compared to N-terminally truncated versions, rapidly down-selected a promising lead vaccine candidate, and developed a high-yield purification process to express immunologically active, intact antigen for clinical trial material production. The rCSP, when formulated with various adjuvants, induced antigen-specific antibody responses as measured by enzyme-linked immunosorbent assay (ELISA and immunofluorescence assay (IFA, as well as CD4+ T-cell responses as determined by ELISpot. The adjuvanted rCSP vaccine conferred protection in mice when challenged with transgenic P. berghei sporozoites containing the P. falciparum repeat region of CSP. Furthermore, heterologous prime/boost regimens with adjuvanted rCSP and an adenovirus type 35-vectored CSP (Ad35CS showed modest improvements in eliciting CSP-specific T-cell responses and anti-malarial protection, depending on the order of vaccine delivery. Collectively, these data support the importance of further clinical development of adjuvanted rCSP, either as a stand-alone product or as one of the components in a heterologous prime

  14. Antigenicity and immunogenicity of a novel Plasmodium vivax circumsporozoite derived synthetic vaccine construct

    DEFF Research Database (Denmark)

    Céspedes, Nora; Jiménez, Eliécer; Lopez-Perez, Mary

    2014-01-01

    BACKGROUND: The circumsporozoite (CS) protein is a major malaria sporozoite surface antigen currently being considered as vaccine candidate. Plasmodium vivax CS (PvCS) protein comprises a dimorphic central repeat fragment flanked by conserved regions that contain functional domains involved in pa...

  15. Rodent malaria: BCG-induced protection and immunosuppression

    International Nuclear Information System (INIS)

    Smrkovski, L.L.; Strickland, G.T.

    1978-01-01

    One dose of 10 7 viable units of Mycobacterium bovis, strain BCG, protected a significant number of Swiss mice from a primary challenge with 10 4 thoracic sporozoites of Plasmodium berghei. Immunization with irradiated sporozoites induced greater protection than that observed in BCG-treated animals. Mice treated with BCG and surviving a primary sporozoite challenge were not protected from rechallenge, whereas mice immunized with irradiated sporozoites and surviving initial challenge of sporozoites were solidly immune to further challenge. Immunizing mice with BCG and irradiated sporozoites simulataneously resulted in a synergistic effect of increased protection against a primary challenge of sporozoites only if the two immunogens were administered on the same day and if the mice were challenged 1 to 3 days later. Mice given BCG and irradiated sporozoites and surviving a primary challenge of sporozoites were unable to survive rechallenge. BCG given to mice previously immunized with irradiated sporozoites suppressed their protective immunity against sporozoite challenge

  16. Gene disruption of Plasmodium falciparum p52 results in attenuation of malaria liver stage development in cultured primary human hepatocytes.

    Directory of Open Access Journals (Sweden)

    Ben C L van Schaijk

    Full Text Available Difficulties with inducing sterile and long lasting protective immunity against malaria with subunit vaccines has renewed interest in vaccinations with attenuated Plasmodium parasites. Immunizations with sporozoites that are attenuated by radiation (RAS can induce strong protective immunity both in humans and rodent models of malaria. Recently, in rodent parasites it has been shown that through the deletion of a single gene, sporozoites can also become attenuated in liver stage development and, importantly, immunization with these sporozoites results in immune responses identical to RAS. The promise of vaccination using these genetically attenuated sporozoites (GAS depends on translating the results in rodent malaria models to human malaria. In this study, we perform the first essential step in this transition by disrupting, p52, in P. falciparum an ortholog of the rodent parasite gene, p36p, which we had previously shown can confer long lasting protective immunity in mice. These P. falciparum P52 deficient sporozoites demonstrate gliding motility, cell traversal and an invasion rate into primary human hepatocytes in vitro that is comparable to wild type sporozoites. However, inside the host hepatocyte development is arrested very soon after invasion. This study reveals, for the first time, that disrupting the equivalent gene in both P. falciparum and rodent malaria Plasmodium species generates parasites that become similarly arrested during liver stage development and these results pave the way for further development of GAS for human use.

  17. The Plasmodium PHIST and RESA-Like Protein Families of Human and Rodent Malaria Parasites

    Science.gov (United States)

    Moreira, Cristina K.; Naissant, Bernina; Coppi, Alida; Bennett, Brandy L.; Aime, Elena; Franke-Fayard, Blandine; Janse, Chris J.; Coppens, Isabelle; Sinnis, Photini; Templeton, Thomas J.

    2016-01-01

    The phist gene family has members identified across the Plasmodium genus, defined by the presence of a domain of roughly 150 amino acids having conserved aromatic residues and an all alpha-helical structure. The family is highly amplified in P. falciparum, with 65 predicted genes in the genome of the 3D7 isolate. In contrast, in the rodent malaria parasite P. berghei 3 genes are identified, one of which is an apparent pseudogene. Transcripts of the P. berghei phist genes are predominant in schizonts, whereas in P. falciparum transcript profiles span different asexual blood stages and gametocytes. We pursued targeted disruption of P. berghei phist genes in order to characterize a simplistic model for the expanded phist gene repertoire in P. falciparum. Unsuccessful attempts to disrupt P. berghei PBANKA_114540 suggest that this phist gene is essential, while knockout of phist PBANKA_122900 shows an apparent normal progression and non-essential function throughout the life cycle. Epitope-tagging of P. falciparum and P. berghei phist genes confirmed protein export to the erythrocyte cytoplasm and localization with a punctate pattern. Three P. berghei PEXEL/HT-positive exported proteins exhibit at least partial co-localization, in support of a common vesicular compartment in the cytoplasm of erythrocytes infected with rodent malaria parasites. PMID:27022937

  18. Compositional and expression analyses of the glideosome during the Plasmodium life cycle reveal an additional myosin light chain required for maximum motility.

    Science.gov (United States)

    Green, Judith L; Wall, Richard J; Vahokoski, Juha; Yusuf, Noor A; Ridzuan, Mohd A Mohd; Stanway, Rebecca R; Stock, Jessica; Knuepfer, Ellen; Brady, Declan; Martin, Stephen R; Howell, Steven A; Pires, Isa P; Moon, Robert W; Molloy, Justin E; Kursula, Inari; Tewari, Rita; Holder, Anthony A

    2017-10-27

    Myosin A (MyoA) is a Class XIV myosin implicated in gliding motility and host cell and tissue invasion by malaria parasites. MyoA is part of a membrane-associated protein complex called the glideosome, which is essential for parasite motility and includes the MyoA light chain myosin tail domain-interacting protein (MTIP) and several glideosome-associated proteins (GAPs). However, most studies of MyoA have focused on single stages of the parasite life cycle. We examined MyoA expression throughout the Plasmodium berghei life cycle in both mammalian and insect hosts. In extracellular ookinetes, sporozoites, and merozoites, MyoA was located at the parasite periphery. In the sexual stages, zygote formation and initial ookinete differentiation precede MyoA synthesis and deposition, which occurred only in the developing protuberance. In developing intracellular asexual blood stages, MyoA was synthesized in mature schizonts and was located at the periphery of segmenting merozoites, where it remained throughout maturation, merozoite egress, and host cell invasion. Besides the known GAPs in the malaria parasite, the complex included GAP40, an additional myosin light chain designated essential light chain (ELC), and several other candidate components. This ELC bound the MyoA neck region adjacent to the MTIP-binding site, and both myosin light chains co-located to the glideosome. Co-expression of MyoA with its two light chains revealed that the presence of both light chains enhances MyoA-dependent actin motility. In conclusion, we have established a system to study the interplay and function of the three glideosome components, enabling the assessment of inhibitors that target this motor complex to block host cell invasion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Transcription status of vaccine candidate genes of Plasmodium falciparum during the hepatic phase of its life cycle.

    NARCIS (Netherlands)

    Bodescot, M.; Silvie, O.; Siau, A.; Refour, P.; Pino, P.; Franetich, J.F.; Hannoun, L.; Sauerwein, R.W.; Mazier, D.

    2004-01-01

    The CSP, EMP2/MESA, MSP2, MSP3, MSP5, RAP1, RAP2, RESA1, SERA1 and SSP2/TRAP genes of Plasmodium falciparum are vaccine candidates. The hepatic phase of the infection is of major interest due to the protection induced by immunization with radiation-attenuated sporozoites. We therefore performed

  20. Oral Salmonella: malaria circumsporozoite recombinants induce specific CD8+ cytotoxic T cells

    OpenAIRE

    1990-01-01

    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+ ...

  1. A comprehensive survey of the Plasmodium life cycle by genomic, transcriptomic, and proteomic analyses.

    Science.gov (United States)

    Hall, Neil; Karras, Marianna; Raine, J Dale; Carlton, Jane M; Kooij, Taco W A; Berriman, Matthew; Florens, Laurence; Janssen, Christoph S; Pain, Arnab; Christophides, Georges K; James, Keith; Rutherford, Kim; Harris, Barbara; Harris, David; Churcher, Carol; Quail, Michael A; Ormond, Doug; Doggett, Jon; Trueman, Holly E; Mendoza, Jacqui; Bidwell, Shelby L; Rajandream, Marie-Adele; Carucci, Daniel J; Yates, John R; Kafatos, Fotis C; Janse, Chris J; Barrell, Bart; Turner, C Michael R; Waters, Andrew P; Sinden, Robert E

    2005-01-07

    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) housekeeping; (ii) host-related; (iii) strategy-specific related to invasion, asexual replication, and sexual development; and (iv) stage-specific. We observed posttranscriptional gene silencing through translational repression of messenger RNA during sexual development, and a 47-base 3' untranslated region motif is implicated in this process.

  2. Co-localization of a CD1d-binding glycolipid with a radiation-attenuated sporozoite vaccine in LN-resident DCs for a robust adjuvant effect

    OpenAIRE

    Li, Xiangming; Kawamura, Akira; Andrews, Chasity D.; Miller, Jessica L.; Wu, Douglass; Tsao, Tiffany; Zhang, Min; Oren, Deena; Padte, Neal N.; Porcelli, Steven A.; Wong, Chi-Huey; Kappe, Stefan H. I.; Ho, David D.; Tsuji, Moriya

    2015-01-01

    A CD1d-binding glycolipid, α-Galactosylceramide (αGalCer), activates invariant natural killer T (iNKT) cells and acts as an adjuvant. We previously identified a fluorinated phenyl ring-modified αGalCer analog, 7DW8-5, displaying nearly 100-fold stronger CD1d binding affinity. In the present study, 7DW8-5 was found to exert a more potent adjuvant effect than αGalCer for a vaccine based on radiation-attenuated sporozoites (RAS) of a rodent malaria parasite, Plasmodium yoelii, also referred to a...

  3. Genome-wide functional analysis of plasmodium protein phosphatases reveals key regulators of parasite development and differentiation

    KAUST Repository

    Guttery, David S.

    2014-07-09

    Reversible protein phosphorylation regulated by kinases and phosphatases controls many cellular processes. Although essential functions for the malaria parasite kinome have been reported, the roles of most protein phosphatases (PPs) during Plasmodium development are unknown. We report a functional analysis of the Plasmodium berghei protein phosphatome, which exhibits high conservation with the P. falciparum phosphatome and comprises 30 predicted PPs with differential and distinct expression patterns during various stages of the life cycle. Gene disruption analysis of P. berghei PPs reveals that half of the genes are likely essential for asexual blood stage development, whereas six are required for sexual development/sporogony in mosquitoes. Phenotypic screening coupled with transcriptome sequencing unveiled morphological changes and altered gene expression in deletion mutants of two N-myristoylated PPs. These findings provide systematic functional analyses of PPs in Plasmodium, identify how phosphatases regulate parasite development and differentiation, and can inform the identification of drug targets for malaria. © 2014 The Authors.

  4. Genome-wide functional analysis of plasmodium protein phosphatases reveals key regulators of parasite development and differentiation

    KAUST Repository

    Guttery, David  S.; Poulin, Benoit; Ramaprasad, Abhinay; Wall, Richard  J.; Ferguson, David  J.P.; Brady, Declan; Patzewitz, Eva-Maria; Whipple, Sarah; Straschil, Ursula; Wright, Megan  H.; Mohamed, Alyaa  M.A.H.; Radhakrishnan, Anand; Arold, Stefan T.; Tate, Edward  W.; Holder, Anthony  A.; Wickstead, Bill; Pain, Arnab; Tewari, Rita

    2014-01-01

    Reversible protein phosphorylation regulated by kinases and phosphatases controls many cellular processes. Although essential functions for the malaria parasite kinome have been reported, the roles of most protein phosphatases (PPs) during Plasmodium development are unknown. We report a functional analysis of the Plasmodium berghei protein phosphatome, which exhibits high conservation with the P. falciparum phosphatome and comprises 30 predicted PPs with differential and distinct expression patterns during various stages of the life cycle. Gene disruption analysis of P. berghei PPs reveals that half of the genes are likely essential for asexual blood stage development, whereas six are required for sexual development/sporogony in mosquitoes. Phenotypic screening coupled with transcriptome sequencing unveiled morphological changes and altered gene expression in deletion mutants of two N-myristoylated PPs. These findings provide systematic functional analyses of PPs in Plasmodium, identify how phosphatases regulate parasite development and differentiation, and can inform the identification of drug targets for malaria. © 2014 The Authors.

  5. Plasmodium falciparum full life cycle and Plasmodium ovale liver stages in humanized mice.

    Science.gov (United States)

    Soulard, Valérie; Bosson-Vanga, Henriette; Lorthiois, Audrey; Roucher, Clémentine; Franetich, Jean-François; Zanghi, Gigliola; Bordessoulles, Mallaury; Tefit, Maurel; Thellier, Marc; Morosan, Serban; Le Naour, Gilles; Capron, Frédérique; Suemizu, Hiroshi; Snounou, Georges; Moreno-Sabater, Alicia; Mazier, Dominique

    2015-07-24

    Experimental studies of Plasmodium parasites that infect humans are restricted by their host specificity. Humanized mice offer a means to overcome this and further provide the opportunity to observe the parasites in vivo. Here we improve on previous protocols to achieve efficient double engraftment of TK-NOG mice by human primary hepatocytes and red blood cells. Thus, we obtain the complete hepatic development of P. falciparum, the transition to the erythrocytic stages, their subsequent multiplication, and the appearance of mature gametocytes over an extended period of observation. Furthermore, using sporozoites derived from two P. ovale-infected patients, we show that human hepatocytes engrafted in TK-NOG mice sustain maturation of the liver stages, and the presence of late-developing schizonts indicate the eventual activation of quiescent parasites. Thus, TK-NOG mice are highly suited for in vivo observations on the Plasmodium species of humans.

  6. The evolution and diversity of a low complexity vaccine candidate, merozoite surface protein 9 (MSP-9), in Plasmodium vivax and closely related species.

    Science.gov (United States)

    Chenet, Stella M; Pacheco, M Andreína; Bacon, David J; Collins, William E; Barnwell, John W; Escalante, Ananias A

    2013-12-01

    The merozoite surface protein-9 (MSP-9) has been considered a target for an anti-malarial vaccine since it is one of many proteins involved in the erythrocyte invasion, a critical step in the parasite life cycle. Orthologs encoding this antigen have been found in all known species of Plasmodium parasitic to primates. In order to characterize and investigate the extent and maintenance of MSP-9 genetic diversity, we analyzed DNA sequences of the following malaria parasite species: Plasmodium falciparum, Plasmodium reichenowi, Plasmodium chabaudi, Plasmodium yoelii, Plasmodium berghei, Plasmodium coatneyi, Plasmodium gonderi, Plasmodium knowlesi, Plasmodium inui, Plasmodium simiovale, Plasmodium fieldi, Plasmodium cynomolgi and Plasmodium vivax and evaluated the signature of natural selection in all MSP-9 orthologs. Our findings suggest that the gene encoding MSP-9 is under purifying selection in P. vivax and closely related species. We further explored how selection affected different regions of MSP-9 by comparing the polymorphisms in P. vivax and P. falciparum, and found contrasting patterns between these two species that suggest differences in functional constraints. This observation implies that the MSP-9 orthologs in human parasites may interact differently with the host immune response. Thus, studies carried out in one species cannot be directly translated into the other. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Translational repression of the cpw-wpc gene family in the malaria parasite Plasmodium

    KAUST Repository

    Rao, Pavitra N.

    2016-06-14

    The technical challenges of working with the sexual stages of the malaria parasite Plasmodium have hindered the characterization of sexual stage antigens in the quest for a successful malaria transmission-blocking vaccine. One such predicted and largely uncharacterized group of sexual stage candidate antigens is the CPW-WPC family of proteins. CPW-WPC proteins are named for a characteristic domain that contains two conserved motifs, CPxxW and WPC. Conserved across Apicomplexa, this family is also present earlier in the Alveolata in the free-living, non-parasitophorous, photosynthetic chromerids, Chromera and Vitrella. In P. falciparum and P. berghei blood stage parasites the transcripts of all nine cpw-wpc genes have been detected in gametocytes. RNA immunoprecipitation followed by reverse transcriptase-PCR reveals all P. berghei cpw-wpc transcripts to be bound by the translational repressors DOZI and CITH, and thus are likely under translational control prior to transmission from the rodent host to the mosquito vector in P. berghei. The GFP tagging of two endogenous P. berghei genes confirmed translational silencing in the gametocyte and translation in ookinetes. Establishing a luciferase transgene assay we show that the 3′ untranslated region of PF3D7_1331400 controls protein expression of this reporter in P. falciparum gametocytes. Our analyses suggest that cpw-wpc genes are translationally silenced in gametocytes across Plasmodium spp. and activated during ookinete formation and thus may have a role in transmission to the mosquito.

  8. Translational repression of the cpw-wpc gene family in the malaria parasite Plasmodium

    KAUST Repository

    Rao, Pavitra N.; Santos, Jorge M.; Pain, Arnab; Templeton, Thomas J.; Mair, Gunnar R.

    2016-01-01

    The technical challenges of working with the sexual stages of the malaria parasite Plasmodium have hindered the characterization of sexual stage antigens in the quest for a successful malaria transmission-blocking vaccine. One such predicted and largely uncharacterized group of sexual stage candidate antigens is the CPW-WPC family of proteins. CPW-WPC proteins are named for a characteristic domain that contains two conserved motifs, CPxxW and WPC. Conserved across Apicomplexa, this family is also present earlier in the Alveolata in the free-living, non-parasitophorous, photosynthetic chromerids, Chromera and Vitrella. In P. falciparum and P. berghei blood stage parasites the transcripts of all nine cpw-wpc genes have been detected in gametocytes. RNA immunoprecipitation followed by reverse transcriptase-PCR reveals all P. berghei cpw-wpc transcripts to be bound by the translational repressors DOZI and CITH, and thus are likely under translational control prior to transmission from the rodent host to the mosquito vector in P. berghei. The GFP tagging of two endogenous P. berghei genes confirmed translational silencing in the gametocyte and translation in ookinetes. Establishing a luciferase transgene assay we show that the 3′ untranslated region of PF3D7_1331400 controls protein expression of this reporter in P. falciparum gametocytes. Our analyses suggest that cpw-wpc genes are translationally silenced in gametocytes across Plasmodium spp. and activated during ookinete formation and thus may have a role in transmission to the mosquito.

  9. Identification of a surface antigen on Theileria parva sporozoites by monoclonal antibody.

    OpenAIRE

    Dobbelaere, D A; Shapiro, S Z; Webster, P

    1985-01-01

    A mouse monoclonal antibody (mAbD1) that neutralizes sporozoites of different stocks of the protozoan parasite Theileria parva has been used to localize and identify a sporozoite antigen. Protein A-colloidal gold was used to localize bound mAbD1 in immunoelectron microscopic studies. mAbD1 bound to sporozoite antigen, which was evenly spread over the surface of all sporozoites. Immune complexes were obtained by incubation of sporozoite suspensions with mAbD1 followed by Zwittergent 3-14 extra...

  10. Improvement of Theileria parva sporozoite vaccine against East ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Mobile Nav Footer Links ... Improvement of Theileria parva sporozoite vaccine against East Coast fever ... Mortality rates approach 90% in susceptible cattle, and animals that recover are long-term Theileria parva ... Global Alliance for Livestock Veterinary Medicines (GALVmed) for technology distribution to endemic regions.

  11. The role of cGMP signalling in regulating life cycle progression of Plasmodium.

    Science.gov (United States)

    Hopp, Christine S; Bowyer, Paul W; Baker, David A

    2012-08-01

    The 3'-5'-cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG) is the main mediator of cGMP signalling in the malaria parasite. This article reviews the role of PKG in Plasmodium falciparum during gametogenesis and blood stage schizont rupture, as well as the role of the Plasmodium berghei orthologue in ookinete differentiation and motility, and liver stage schizont development. The current views on potential effector proteins downstream of PKG and the mechanisms that may regulate cyclic nucleotide levels are presented. Copyright © 2012 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  12. Protein O-fucosylation in Plasmodium falciparum ensures efficient infection of mosquito and vertebrate hosts.

    Science.gov (United States)

    Lopaticki, Sash; Yang, Annie S P; John, Alan; Scott, Nichollas E; Lingford, James P; O'Neill, Matthew T; Erickson, Sara M; McKenzie, Nicole C; Jennison, Charlie; Whitehead, Lachlan W; Douglas, Donna N; Kneteman, Norman M; Goddard-Borger, Ethan D; Boddey, Justin A

    2017-09-15

    O-glycosylation of the Plasmodium sporozoite surface proteins CSP and TRAP was recently identified, but the role of this modification in the parasite life cycle and its relevance to vaccine design remain unclear. Here, we identify the Plasmodium protein O-fucosyltransferase (POFUT2) responsible for O-glycosylating CSP and TRAP. Genetic disruption of POFUT2 in Plasmodium falciparum results in ookinetes that are attenuated for colonizing the mosquito midgut, an essential step in malaria transmission. Some POFUT2-deficient parasites mature into salivary gland sporozoites although they are impaired for gliding motility, cell traversal, hepatocyte invasion, and production of exoerythrocytic forms in humanized chimeric liver mice. These defects can be attributed to destabilization and incorrect trafficking of proteins bearing thrombospondin repeats (TSRs). Therefore, POFUT2 plays a similar role in malaria parasites to that in metazoans: it ensures the trafficking of Plasmodium TSR proteins as part of a non-canonical glycosylation-dependent endoplasmic reticulum protein quality control mechanism.The role of O-glycosylation in the malaria life cycle is largely unknown. Here, the authors identify a Plasmodium protein O-fucosyltransferase and show that it is important for normal trafficking of a subset of surface proteins, particularly CSP and TRAP, and efficient infection of mosquito and vertebrate hosts.

  13. Plasmodium immunomics.

    Science.gov (United States)

    Doolan, Denise L

    2011-01-01

    The Plasmodium parasite, the causative agent of malaria, is an excellent model for immunomic-based approaches to vaccine development. The Plasmodium parasite has a complex life cycle with multiple stages and stage-specific expression of ∼5300 putative proteins. No malaria vaccine has yet been licensed. Many believe that an effective vaccine will need to target several antigens and multiple stages, and will require the generation of both antibody and cellular immune responses. Vaccine efforts to date have been stage-specific and based on only a very limited number of proteins representing Plasmodium parasite life cycle with immune responses implicated in parasite elimination and control. Immunomic approaches which enable the selection of the best possible targets by prioritising antigens according to clinically relevant criteria may overcome the problem of poorly immunogenic, poorly protective vaccines that has plagued malaria vaccine developers for the past 25 years. Herein, current progress and perspectives regarding Plasmodium immunomics are reviewed. Copyright © 2010 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  14. The macromolecular complex of ICP and falcipain-2 from Plasmodium: preparation, crystallization and preliminary X-ray diffraction analysis

    International Nuclear Information System (INIS)

    Hansen, Guido; Schwarzloh, Britta; Rennenberg, Annika; Heussler, Volker T.; Hilgenfeld, Rolf

    2011-01-01

    The macromolecular complex of ICP (inhibitor of cysteine proteases) from P. berghei and falcipain-2 from P. falciparum has been prepared and crystallized, and a diffraction data set has been collected to a resolution of 2.6 Å. The malaria parasite Plasmodium depends on the tight control of cysteine-protease activity throughout its life cycle. Recently, the characterization of a new class of potent inhibitors of cysteine proteases (ICPs) secreted by Plasmodium has been reported. Here, the recombinant production, purification and crystallization of the inhibitory C-terminal domain of ICP from P. berghei in complex with the P. falciparum haemoglobinase falcipain-2 is described. The 1:1 complex was crystallized in space group P4 3 , with unit-cell parameters a = b = 71.15, c = 120.09 Å. A complete diffraction data set was collected to a resolution of 2.6 Å

  15. Using green fluorescent malaria parasites to screen for permissive vector mosquitoes

    Directory of Open Access Journals (Sweden)

    Martin Beatrice

    2006-03-01

    Full Text Available Abstract Background 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 P. yoelii can infect the South American mosquito, Anopheles albimanus, while P. berghei cannot. Methods P. berghei lines that express the green fluorescent protein were used to screen for mosquitoes that are susceptible to infection by P. berghei. Live mosquitoes were examined and screened for the presence of a fluorescent signal in the abdomen. Infected mosquitoes were then examined by time-lapse microscopy to reveal the dynamic behaviour of sporozoites in haemolymph and extracted salivary glands. Results A single fluorescent oocyst can be detected in live mosquitoes and P. berghei can infect A. albimanus. As in other mosquitoes, P. berghei sporozoites can float through the haemolymph and invade A. albimanus salivary glands and they are infectious in mice after subcutaneous injection. Conclusion Fluorescent Plasmodium parasites can be used to rapidly screen susceptible mosquitoes. These results open the way to develop a laboratory model in countries where importation of A. gambiae and A. stephensi is not allowed.

  16. Schistosoma mansoni infection suppresses the growth of Plasmodium yoelii parasites in the liver and reduces gametocyte infectivity to mosquitoes.

    Directory of Open Access Journals (Sweden)

    Taeko Moriyasu

    2018-01-01

    Full Text Available Malaria and schistosomiasis are major parasitic diseases causing morbidity and mortality in the tropics. Epidemiological surveys have revealed coinfection rates of up to 30% among children in Sub-Saharan Africa. To investigate the impact of coinfection of these two parasites on disease epidemiology and pathology, we carried out coinfection studies using Plasmodium yoelii and Schistosoma mansoni in mice. Malaria parasite growth in the liver following sporozoite inoculation is significantly inhibited in mice infected with S. mansoni, so that when low numbers of sporozoites are inoculated, there is a large reduction in the percentage of mice that go on to develop blood stage malaria. Furthermore, gametocyte infectivity is much reduced in mice with S. mansoni infections. These results have profound implications for understanding the interactions between Plasmodium and Schistosoma species, and have implications for the control of malaria in schistosome endemic areas.

  17. Multidrug ATP-binding cassette transporters are essential for hepatic development of Plasmodium sporozoites

    NARCIS (Netherlands)

    Rijpma, S.R.; Velden, M. van der; Gonzalez-Pons, M.; Annoura, T.; Schaijk, B.C.L. van; Gemert, G.J.A. van; Heuvel, J.M.W. van den; Ramesar, J.; Chevalley-Maurel, S.; Ploemen, I.H.; Khan, S.M.; Franetich, J.F.; Mazier, D.; Wilt, J.H.W. de; Serrano, A.E.; Russel, F.G.; Janse, C.J.; Sauerwein, R.W.; Koenderink, J.B.; Franke-Fayard, B.M.

    2016-01-01

    Multidrug resistance-associated proteins (MRPs) belong to the C-family of ATP-binding cassette (ABC) transport proteins and are known to transport a variety of physiologically important compounds and to be involved in the extrusion of pharmaceuticals. Rodent malaria parasites encode a single ABC

  18. Identification of vital and dispensable sulfur utilization factors in the Plasmodium apicoplast.

    Directory of Open Access Journals (Sweden)

    Joana M Haussig

    Full Text Available Iron-sulfur [Fe-S] clusters are ubiquitous and critical cofactors in diverse biochemical processes. They are assembled by distinct [Fe-S] cluster biosynthesis pathways, typically in organelles of endosymbiotic origin. Apicomplexan parasites, including Plasmodium, the causative agent of malaria, harbor two separate [Fe-S] cluster biosynthesis pathways in the their mitochondrion and apicoplast. In this study, we systematically targeted the five nuclear-encoded sulfur utilization factors (SUF of the apicoplast [Fe-S] cluster biosynthesis pathway by experimental genetics in the murine malaria model parasite Plasmodium berghei. We show that four SUFs, namely SUFC, D, E, and S are refractory to targeted gene deletion, validating them as potential targets for antimalarial drug development. We achieved targeted deletion of SUFA, which encodes a potential [Fe-S] transfer protein, indicative of a dispensable role during asexual blood stage growth in vivo. Furthermore, no abnormalities were observed during Plasmodium life cycle progression in the insect and mammalian hosts. Fusion of a fluorescent tag to the endogenous P. berghei SUFs demonstrated that all loci were accessible to genetic modification and that all five tagged SUFs localize to the apicoplast. Together, our experimental genetics analysis identifies the key components of the SUF [Fe-S] cluster biosynthesis pathway in the apicoplast of a malarial parasite and shows that absence of SUFC, D, E, or S is incompatible with Plasmodium blood infection in vivo.

  19. An Epithelial Serine Protease, AgESP, Is Required for Plasmodium Invasion in the Mosquito Anopheles gambiae

    Czech Academy of Sciences Publication Activity Database

    Rodrigues, J.; Oliveira, G. A.; Kotsyfakis, Michalis; Dixit, R.; Molina-Cruz, A.; Jochim, R.; Barillas-Mury, C.

    2012-01-01

    Roč. 7, č. 4 (2012), e35210 E-ISSN 1932-6203 Institutional support: RVO:60077344 Keywords : malaria * mosquito * serine protease * sporozoites * ookinetes * gene silencing * midgut * salivary glands * Plasmodium falciparum * Anopheles gambiae Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.730, year: 2012 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0035210

  20. Liver or blood-stage arrest during malaria sporozoite immunization: the later the better?

    NARCIS (Netherlands)

    Nganou Makamdop, C.K.; Sauerwein, R.W.

    2013-01-01

    So far, the best immunization strategies to achieve high levels of protection against malaria are based on whole parasites. Complete sterile protection can be obtained in rodent models after immunization with sporozoites and chemoprophylaxis, or with sporozoites attenuated either genetically or by

  1. The trial detection of malaria sporozoit in field-collected mosquito by immunoradiometric assay in Thailand

    International Nuclear Information System (INIS)

    Kasemsuth, R.; Asavanich, A.; Sucharit, S.; Vutikes, S.; Vutikes, M.; Patamatum, S.

    1988-01-01

    The sporozoite rate, species of parasite and vector are important in the epidemiology of malaria. The investigation of sporozoite by dissection and examination under a microscope is time-consuming and it could be done only on freshly killed mosquitoes. Immunoradiometric assay (IRMA) that can detect, identify and quantify malaria sporozoite (Zavala et al., 1982) was therefore applied to detect sporozoite in laboratory-maintained Anopheles dirus and wild-caught mosquitoes. Study on P. falciparum-infected An. dirus showed that the circumsporozoite (CS) antigen was first found in the abdomen on the 10th day post-infection, whilst the sporozoites were examined in salivary glands from day 15 onwards. The malaria infection in wild-caught mosquitoes were investigated in Anopheles spp collected by human baites from three endemic areas in Thailand. Since the sporozoite rate refers to the presence of sporozoite in the salivary gland, then only head-thorax part of the specimens were detected by IRMA to prevent an exaggeration over the true results. It was found that none of mosquitoes collected from Phrae was positive for malaria. Four out of 1243 An. dirus among eight species collected from Chantaburi were positive for P. falciparum with sporozoites ranged from 270 to 3875. Of all ten species collected from Kanchanaburi, two and one out of 3123 An. minimus were positive for P. falciparum and P. vivax with sporozoites found in head-thorax portions were 1880, 2380 and 1026 respectively. It is evident that the IRMA is suitable for the investigation of malaria sporozoites in this region. The application of this technique in the further epidemiological study is in progress

  2. Cysteine-stabilised peptide extract of Morinda lucida (Benth) leaf exhibits antimalarial activity and augments antioxidant defense system in P. berghei-infected mice.

    Science.gov (United States)

    Adebayo, Joseph O; Adewole, Kayode E; Krettli, Antoniana U

    2017-07-31

    Cysteine-stabilised peptides (CSP) are majorly explored for their bioactivities with applications in medicine and agriculture. Morinda lucida leaf is used indigenously for the treatment of malaria; it also contains CSP but the role of CSP in the antimalarial activity of the leaf has not been evaluated. This study was therefore performed to evaluate the antimalarial activity of partially purified cysteine-stabilised peptide extract (PPCPE) of Morinda lucida leaf and its possible augmentation of the antioxidant systems of liver and erythrocytes in murine malaria. PPCPE was prepared from Morinda lucida leaf. The activity of PPCPE was evaluated in vitro against Plasmodium falciparum W2 and its cytotoxicity against a BGM kidney cell line. PPCPE was also evaluated for its antimalarial activity and its effects on selected liver and erythrocyte antioxidant parameters in P. berghei NK65-infected mice. PPCPE was not active against P. falciparum W2 (IC 50 : >50µg/ml) neither was it cytotoxic (MLD 50 : >1000µg/ml). However, PPCPE was active against P. berghei NK65 in vivo, causing 51.52% reduction in parasitaemia at 31.25mg/Kg body weight on day 4 post-inoculation. PPCPE significantly reduced (P activities of glutathione peroxidase, glutathione reductase, superoxide dismutase and catalase in a dose-dependent manner, which was significant (P antimalarial effect and that PPCPE may augment the antioxidant defense system to alleviate the reactive oxygen species-mediated complications of malaria. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  3. Identification and characterization of a liver stage-specific promoter region of the malaria parasite Plasmodium.

    Directory of Open Access Journals (Sweden)

    Susanne Helm

    Full Text Available During the blood meal of a Plasmodium-infected mosquito, 10 to 100 parasites are inoculated into the skin and a proportion of these migrate via the bloodstream to the liver where they infect hepatocytes. The Plasmodium liver stage, despite its clinical silence, represents a highly promising target for antimalarial drug and vaccine approaches. Successfully invaded parasites undergo a massive proliferation in hepatocytes, producing thousands of merozoites that are transported into a blood vessel to infect red blood cells. To successfully develop from the liver stage into infective merozoites, a tight regulation of gene expression is needed. Although this is a very interesting aspect in the biology of Plasmodium, little is known about gene regulation in Plasmodium parasites in general and in the liver stage in particular. We have functionally analyzed a novel promoter region of the rodent parasite Plasmodium berghei that is exclusively active during the liver stage of the parasite. To prove stage-specific activity of the promoter, GFP and luciferase reporter assays have been successfully established, allowing both qualitative and accurate quantitative analysis. To further characterize the promoter region, the transcription start site was mapped by rapid amplification of cDNA ends (5'-RACE. Using promoter truncation experiments and site-directed mutagenesis within potential transcription factor binding sites, we suggest that the minimal promoter contains more than one binding site for the recently identified parasite-specific ApiAP2 transcription factors. The identification of a liver stage-specific promoter in P. berghei confirms that the parasite is able to tightly regulate gene expression during its life cycle. The identified promoter region might now be used to study the biology of the Plasmodium liver stage, which has thus far proven problematic on a molecular level. Stage-specific expression of dominant-negative mutant proteins and

  4. Characterization of the Eimeria maxima sporozoite surface protein IMP1.

    Science.gov (United States)

    Jenkins, M C; Fetterer, R; Miska, K; Tuo, W; Kwok, O; Dubey, J P

    2015-07-30

    The purpose of this study was to characterize Eimeria maxima immune-mapped protein 1 (IMP1) that is hypothesized to play a role in eliciting protective immunity against E. maxima infection in chickens. RT-PCR analysis of RNA from unsporulated and sporulating E. maxima oocysts revealed highest transcription levels at 6-12h of sporulation with a considerable downregulation thereafter. Alignment of IMP1 coding sequence from Houghton, Weybridge, and APU-1 strains of E. maxima revealed single nucleotide polymorphisms that in some instances led to amino acid changes in the encoded protein sequence. The E. maxima (APU-1) IMP1 cDNA sequence was cloned and expressed in 2 different polyHis Escherichia coli expression vectors. Regardless of expression vector, recombinant E. maxima IMP1 (rEmaxIMP1) was fairly unstable in non-denaturing buffer, which is consistent with stability analysis of the primary amino acid sequence. Antisera specific for rEmaxIMP1 identified a single 72 kDa protein or a 61 kDa protein by non-reducing or reducing SDS-PAGE/immunoblotting. Immunofluorescence staining with anti-rEmaxIMP1, revealed intense surface staining of E. maxima sporozoites, with negligible staining of merozoite stages. Immuno-histochemical staining of E. maxima-infected chicken intestinal tissue revealed staining of E. maxima developmental stages in the lamnia propia and crypts at both 24 and 48 h post-infection, and negligible staining thereafter. The expression of IMP1 during early stages of in vivo development and its location on the sporozoite surface may explain in part the immunoprotective effect of this protein against E. maxima infection. Published by Elsevier B.V.

  5. Life cycle studies of the hexose transporter of Plasmodium species and genetic validation of their essentiality.

    Science.gov (United States)

    Slavic, Ksenija; Straschil, Ursula; Reininger, Luc; Doerig, Christian; Morin, Christophe; Tewari, Rita; Krishna, Sanjeev

    2010-03-01

    A Plasmodium falciparum hexose transporter (PfHT) has previously been shown to be a facilitative glucose and fructose transporter. Its expression in Xenopus laevis oocytes and the use of a glucose analogue inhibitor permitted chemical validation of PfHT as a novel drug target. Following recent re-annotations of the P. falciparum genome, other putative sugar transporters have been identified. To investigate further if PfHT is the key supplier of hexose to P. falciparum and to extend studies to different stages of Plasmodium spp., we functionally analysed the hexose transporters of both the human parasite P. falciparum and the rodent parasite Plasmodium berghei using gene targeting strategies. We show here the essential function of pfht for the erythrocytic parasite growth as it was not possible to knockout pfht unless the gene was complemented by an episomal construct. Also, we show that parasites are rescued from the toxic effect of a glucose analogue inhibitor when pfht is overexpressed in these transfectants. We found that the rodent malaria parasite orthologue, P. berghei hexose transporter (PbHT) gene, was similarly refractory to knockout attempts. However, using a single cross-over transfection strategy, we generated transgenic P. berghei parasites expressing a PbHT-GFP fusion protein suggesting that locus is amenable for gene targeting. Analysis of pbht-gfp transgenic parasites showed that PbHT is constitutively expressed through all the stages in the mosquito host in addition to asexual stages. These results provide genetic support for prioritizing PfHT as a target for novel antimalarials that can inhibit glucose uptake and kill parasites, as well as unveiling the expression of this hexose transporter in mosquito stages of the parasite, where it is also likely to be critical for survival.

  6. Asiatic acid influences glucose homeostasis in P. berghei murine ...

    African Journals Online (AJOL)

    Background: Glucose homeostasis derangement is a common pathophysiology of malaria whose aetiology is still controversial. The Plasmodium parasite, immunological and inflammatory responses, as well as chemotherapeutics currently used cause hypoglycaemia in malaria. Anti-parasitic and anti-disease drugs are ...

  7. The susceptibility of Anopheles lesteri to infection with Korean strain of Plasmodium vivax

    Directory of Open Access Journals (Sweden)

    Kim Tong-Soo

    2009-03-01

    Full Text Available Abstract Background Following its recent re-emergence, malaria has gained renewed attention as a serious infectious disease in Korea. Three species of the Hyrcanusgroup, Anopheles lesteri, Anopheles sinensis and Anopheles pullus, have long been suspected malaria vectors. However, opinions about their vector ability are controversial. The present study was designed with the aim of determining the susceptibility of these mosquitoes to a Korean isolate of Plasmodium vivax. Also, An. sinensis is primarily suspected to be vector of malaria in Korea, but in Thailand, the same species is described to have less medical importance. Therefore, comparative susceptibility of Thai and Korean strains of An. sinensis with Thai strain of P. vivax may be helpful to understand whether these geographically different strains exhibit differences in their susceptibility or not. Methods The comparative susceptibility of An. lesteri, An. sinensis and An. pullus was studied by feeding laboratory-reared mosquitoes on blood from patients carrying gametocytes from Korea and Thailand. Results In experimental feeding with Korean strain of P. vivax, oocysts developed in An. lesteri, An. sinensis and An. pullus. Salivary gland sporozoites were detected only in An. lesteri and An. sinensis but not in An. pullus. Large differences were found in the number of sporozoites in the salivary glands, with An. lesteri carrying much higher densities, up to 2,105 sporozoites in a single microscope field of 750 × 560 μM, whereas a maximum of 14 sporozoites were found in any individual salivary gland of An. sinensis. Similar results were obtained from a susceptibility test of two different strains of An. sinensis to Thai isolate of P. vivax, and differences in vector susceptibility according to geographical variation were not detected. Conclusion The high sporozoite rate and sporozoite loads of An. lesteri indicate that this species is highly susceptible to infection with P. vivax

  8. Comparative susceptibility of introduced forest-dwelling mosquitoes in Hawai'i to avian malaria, Plasmodium relictum

    Science.gov (United States)

    Lapointe, D.A.; Goff, M.L.; Atkinson, C.T.

    2005-01-01

    To identify potential vectors of avian malaria in Hawaiian native forests, the innate susceptibility of Aedes albopictus, Wyeomyia mitchellii, and Culex quinquefasciatus from 3 geographical sites along an altitudinal gradient was evaluated using local isolates of Plasmodium relictum. Mosquitoes were dissected 5-8 and 9-13 days postinfective blood meal and microscopically examined for oocysts and salivary-gland sporozoites. Sporogony was completed in all 3 species, but prevalence between species varied significantly. Oocysts were detected in 1-2% and sporozoites in 1-7% of Aedes albopictus that fed on infected ducklings. Wyeomyia mitchellii was slightly more susceptible, with 7-19% and 7% infected with oocysts and sporozoites, respectively. In both species, the median oocyst number was 5 or below. This is only the second Wyeomyia species reported to support development of a malarial parasite. Conversely, Culex quinquefasciatus from all 3 sites proved very susceptible. Prevalence of oocysts and sporozoites consistently exceeded 70%, regardless of gametocytemia or origin of the P. relictum isolate. In trials for which a maximum 200 oocysts were recorded, the median number of oocysts ranged from 144 to 200. It was concluded that Culex quinquefasciatus is the primary vector of avian malaria in Hawai'i. ?? American Society of Parasitologists 2005.

  9. Assessment of the relative success of sporozoite inoculations in individuals exposed to moderate seasonal transmission

    Directory of Open Access Journals (Sweden)

    Spiegel André

    2009-07-01

    Full Text Available Abstract Background The time necessary for malaria parasite to re-appear in the blood following treatment (re-infection time is an indirect method for evaluating the immune defences operating against pre-erythrocytic and early erythrocytic malaria stages. Few longitudinal data are available in populations in whom malaria transmission level had also been measured. Methods One hundred and ten individuals from the village of Ndiop (Senegal, aged between one and 72 years, were cured of malaria by quinine (25 mg/day oral Quinimax™ in three equal daily doses, for seven days. Thereafter, thick blood films were examined to detect the reappearance of Plasmodium falciparum every week, for 11 weeks after treatment. Malaria transmission was simultaneously measured weekly by night collection of biting mosquitoes. Results Malaria transmission was on average 15.3 infective bites per person during the 77 days follow up. The median reappearance time for the whole study population was 46.8 days, whereas individuals would have received an average one infective bite every 5 days. At the end of the follow-up, after 77 days, 103 of the 110 individuals (93.6%; CI 95% [89.0–98.2] had been re-infected with P. falciparum. The median reappearance time ('re-positivation' was longer in subjects with patent parasitaemia at enrolment than in parasitologically-negative individuals (58 days vs. 45.9; p = 0.03 and in adults > 30 years than in younger subjects (58.6 days vs. 42.7; p = 0.0002. In a multivariate Cox PH model controlling for the sickle cell trait, G6PD deficiency and the type of habitat, the presence of parasitaemia at enrolment and age ≥ 30 years were independently predictive of a reduced risk of re-infection (PH = 0.5 [95% CI: 0.3–0.9] and 0.4; [95% CI: 0.2–0.6] respectively. Conclusion Results indicate the existence of a substantial resistance to sporozoites inoculations, but which was ultimately overcome in almost every individual after 2 1/2 months of

  10. Enlightening the malaria parasite life cycle: bioluminescent Plasmodium in fundamental and applied research

    Directory of Open Access Journals (Sweden)

    Giulia eSiciliano

    2015-05-01

    Full Text Available The unicellular protozoan parasites of the genus Plasmodium impose on human health worldwide the enormous burden of malaria. The possibility to genetically modify several species of malaria parasites represented a major advance in the possibility to elucidate their biology and is now turning laboratory lines of transgenic Plasmodium into precious weapons to fight malaria. Amongst the various genetically modified plasmodia, transgenic parasite lines expressing bioluminescent reporters have been essential to unveil mechanisms of parasite gene expression and to develop in vivo imaging approaches in mouse malaria models. Mainly the human malaria parasite Plasmodium falciparum and the rodent parasite Plasmodium berghei have been engineered to express bioluminescent reporters in almost all the developmental stages of the parasite along its complex life cycle between the insect and the vertebrate hosts. Plasmodium lines expressing conventional and improved luciferase reporters are now gaining a central role to develop cell based assays in the much needed search of new antimalarial drugs and to open innovative approaches for both fundamental and applied research in malaria.

  11. Antimalarial efficacy of MMV390048, an inhibitor of Plasmodium phosphatidylinositol 4-kinase.

    Science.gov (United States)

    Paquet, Tanya; Le Manach, Claire; Cabrera, Diego González; Younis, Yassir; Henrich, Philipp P; Abraham, Tara S; Lee, Marcus C S; Basak, Rajshekhar; Ghidelli-Disse, Sonja; Lafuente-Monasterio, María José; Bantscheff, Marcus; Ruecker, Andrea; Blagborough, Andrew M; Zakutansky, Sara E; Zeeman, Anne-Marie; White, Karen L; Shackleford, David M; Mannila, Janne; Morizzi, Julia; Scheurer, Christian; Angulo-Barturen, Iñigo; Martínez, María Santos; Ferrer, Santiago; Sanz, Laura María; Gamo, Francisco Javier; Reader, Janette; Botha, Mariette; Dechering, Koen J; Sauerwein, Robert W; Tungtaeng, Anchalee; Vanachayangkul, Pattaraporn; Lim, Chek Shik; Burrows, Jeremy; Witty, Michael J; Marsh, Kennan C; Bodenreider, Christophe; Rochford, Rosemary; Solapure, Suresh M; Jiménez-Díaz, María Belén; Wittlin, Sergio; Charman, Susan A; Donini, Cristina; Campo, Brice; Birkholtz, Lyn-Marie; Hanson, Kirsten K; Drewes, Gerard; Kocken, Clemens H M; Delves, Michael J; Leroy, Didier; Fidock, David A; Waterson, David; Street, Leslie J; Chibale, Kelly

    2017-04-26

    As part of the global effort toward malaria eradication, phenotypic whole-cell screening revealed the 2-aminopyridine class of small molecules as a good starting point to develop new antimalarial drugs. Stemming from this series, we found that the derivative, MMV390048, lacked cross-resistance with current drugs used to treat malaria. This compound was efficacious against all Plasmodium life cycle stages, apart from late hypnozoites in the liver. Efficacy was shown in the humanized Plasmodium falciparum mouse model, and modest reductions in mouse-to-mouse transmission were achieved in the Plasmodium berghei mouse model. Experiments in monkeys revealed the ability of MMV390048 to be used for full chemoprotection. Although MMV390048 was not able to eliminate liver hypnozoites, it delayed relapse in a Plasmodium cynomolgi monkey model. Both genomic and chemoproteomic studies identified a kinase of the Plasmodium parasite, phosphatidylinositol 4-kinase, as the molecular target of MMV390048. The ability of MMV390048 to block all life cycle stages of the malaria parasite suggests that this compound should be further developed and may contribute to malaria control and eradication as part of a single-dose combination treatment. Copyright © 2017, American Association for the Advancement of Science.

  12. Implementation of minimally invasive and objective humane endpoints in the study of murine Plasmodium infections

    DEFF Research Database (Denmark)

    Dellavalle, B; Kirchhoff, J; Maretty, L

    2014-01-01

    SUMMARY Defining appropriate and objective endpoints for animal research can be difficult. Previously we evaluated and implemented a body temperature (BT) of ECM) and were interested in a similar endpoint for a model of severe malarial...... anaemia (SMA). Furthermore, we investigate the potential of a minimally invasive, non-contact infrared thermometer for repeated BT measurement. ECM was induced with Plasmodium berghei ANKA infection in C57Bl/6 mice. SMA was induced with Plasmodium chabaudi AS infection in A/J mice. Our previous published...... endpoint was applied in ECM and 30 °C was pre-determined as the lowest permitted limit for termination in SMA according to consultation with the Danish Animal Inspectorate. Infrared thermometer was compared with the rectal probe after cervical dislocation, ECM and SMA. Linear regression analysis of rectal...

  13. Contrasting Inducible Knockdown of the Auxiliary PTEX Component PTEX88 in P. falciparum and P. berghei Unmasks a Role in Parasite Virulence.

    Directory of Open Access Journals (Sweden)

    Scott A Chisholm

    Full Text Available Pathogenesis of malaria infections is linked to remodeling of erythrocytes, a process dependent on the trafficking of hundreds of parasite-derived proteins into the host erythrocyte. Recent studies have demonstrated that the Plasmodium translocon of exported proteins (PTEX serves as the central gateway for trafficking of these proteins, as inducible knockdown of the core PTEX constituents blocked the trafficking of all classes of cargo into the erythrocyte. However, the role of the auxiliary component PTEX88 in protein export remains less clear. Here we have used inducible knockdown technologies in P. falciparum and P. berghei to assess the role of PTEX88 in parasite development and protein export, which reveal that the in vivo growth of PTEX88-deficient parasites is hindered. Interestingly, we were unable to link this observation to a general defect in export of a variety of known parasite proteins, suggesting that PTEX88 functions in a different fashion to the core PTEX components. Strikingly, PTEX88-deficient P. berghei were incapable of causing cerebral malaria despite a robust pro-inflammatory response from the host. These parasites also exhibited a reduced ability to sequester in peripheral tissues and were removed more readily from the circulation by the spleen. In keeping with these findings, PTEX88-deficient P. falciparum-infected erythrocytes displayed reduced binding to the endothelial cell receptor, CD36. This suggests that PTEX88 likely plays a specific direct or indirect role in mediating parasite sequestration rather than making a universal contribution to the trafficking of all exported proteins.

  14. Infection of Laboratory-Colonized Anopheles darlingi Mosquitoes by Plasmodium vivax

    Science.gov (United States)

    Moreno, Marta; Tong, Carlos; Guzmán, Mitchel; Chuquiyauri, Raul; Llanos-Cuentas, Alejandro; Rodriguez, Hugo; Gamboa, Dionicia; Meister, Stephan; Winzeler, Elizabeth A.; Maguina, Paula; Conn, Jan E.; Vinetz, Joseph M.

    2014-01-01

    Anopheles darlingi Root is the most important malaria vector in the Amazonia region of South America. However, continuous propagation of An. darlingi in the laboratory has been elusive, limiting entomological, genetic/genomic, and vector–pathogen interaction studies of this mosquito species. Here, we report the establishment of an An. darlingi colony derived from wild-caught mosquitoes obtained in the northeastern Peruvian Amazon region of Iquitos in the Loreto Department. We show that the numbers of eggs, larvae, pupae, and adults continue to rise at least to the F6 generation. Comparison of feeding Plasmodium vivax ex vivo of F4 and F5 to F1 generation mosquitoes showed the comparable presence of oocysts and sporozoites, with numbers that corresponded to blood-stage asexual parasitemia and gametocytemia, confirming P. vivax vectorial capacity in the colonized mosquitoes. These results provide new avenues for research on An. darlingi biology and study of An. darlingi–Plasmodium interactions. PMID:24534811

  15. Plasmodium Apicoplast Gln-tRNA Gln Biosynthesis Utilizes a Unique GatAB Amidotransferase Essential for Erythrocytic Stage Parasites

    KAUST Repository

    Mailu, Boniface M.

    2015-08-28

    © 2015 by The American Society for Biochemistry and Molecular Biology, Inc. The malaria parasite Plasmodium falciparum apicoplast indirect aminoacylation pathway utilizes a non-discriminating glutamyl-tRNA synthetase to synthesize Glu-tRNAGln and a glutaminyl-tRNA amidotransferase to convert Glu-tRNAGln to Gln-tRNAGln. Here, we show that Plasmodium falciparum and other apicomplexans possess a unique heterodimeric glutamyltRNA amidotransferase consisting of GatA and GatB subunits (GatAB). We localized the P. falciparum GatA and GatB subunits to the apicoplast in blood stage parasites and demonstrated that recombinant GatAB converts Glu-tRNAGln to Gln-tRNAGln in vitro. We demonstrate that the apicoplast GatAB-catalyzed reaction is essential to the parasite blood stages because we could not delete the Plasmodium berghei gene encoding GatA in blood stage parasites in vivo. A phylogenetic analysis placed the split between Plasmodium GatB, archaeal GatE, and bacterial GatB prior to the phylogenetic divide between bacteria and archaea. Moreover, Plasmodium GatA also appears to have emerged prior to the bacterial-archaeal phylogenetic divide. Thus, although GatAB is found in Plasmodium, it emerged prior to the phylogenetic separation of archaea and bacteria.

  16. Plasmodium Apicoplast Gln-tRNA Gln Biosynthesis Utilizes a Unique GatAB Amidotransferase Essential for Erythrocytic Stage Parasites

    KAUST Repository

    Mailu, Boniface M.; Li, Ling; Arthur, Jen; Nelson, Todd M.; Ramasamy, Gowthaman; Fritz-Wolf, Karin; Becker, Katja; Gardner, Malcolm J.

    2015-01-01

    © 2015 by The American Society for Biochemistry and Molecular Biology, Inc. The malaria parasite Plasmodium falciparum apicoplast indirect aminoacylation pathway utilizes a non-discriminating glutamyl-tRNA synthetase to synthesize Glu-tRNAGln and a glutaminyl-tRNA amidotransferase to convert Glu-tRNAGln to Gln-tRNAGln. Here, we show that Plasmodium falciparum and other apicomplexans possess a unique heterodimeric glutamyltRNA amidotransferase consisting of GatA and GatB subunits (GatAB). We localized the P. falciparum GatA and GatB subunits to the apicoplast in blood stage parasites and demonstrated that recombinant GatAB converts Glu-tRNAGln to Gln-tRNAGln in vitro. We demonstrate that the apicoplast GatAB-catalyzed reaction is essential to the parasite blood stages because we could not delete the Plasmodium berghei gene encoding GatA in blood stage parasites in vivo. A phylogenetic analysis placed the split between Plasmodium GatB, archaeal GatE, and bacterial GatB prior to the phylogenetic divide between bacteria and archaea. Moreover, Plasmodium GatA also appears to have emerged prior to the bacterial-archaeal phylogenetic divide. Thus, although GatAB is found in Plasmodium, it emerged prior to the phylogenetic separation of archaea and bacteria.

  17. Colocalization of a CD1d-Binding Glycolipid with a Radiation-Attenuated Sporozoite Vaccine in Lymph Node-Resident Dendritic Cells for a Robust Adjuvant Effect.

    Science.gov (United States)

    Li, Xiangming; Kawamura, Akira; Andrews, Chasity D; Miller, Jessica L; Wu, Douglass; Tsao, Tiffany; Zhang, Min; Oren, Deena; Padte, Neal N; Porcelli, Steven A; Wong, Chi-Huey; Kappe, Stefan H I; Ho, David D; Tsuji, Moriya

    2015-09-15

    A CD1d-binding glycolipid, α-Galactosylceramide (αGalCer), activates invariant NK T cells and acts as an adjuvant. We previously identified a fluorinated phenyl ring-modified αGalCer analog, 7DW8-5, displaying nearly 100-fold stronger CD1d binding affinity. In the current study, 7DW8-5 was found to exert a more potent adjuvant effect than αGalCer for a vaccine based on radiation-attenuated sporozoites of a rodent malaria parasite, Plasmodium yoelii, also referred to as irradiated P. yoelii sporozoites (IrPySpz). 7DW8-5 had a superb adjuvant effect only when the glycolipid and IrPySpz were conjointly administered i.m. Therefore, we evaluated the effect of distinctly different biodistribution patterns of αGalCer and 7DW8-5 on their respective adjuvant activities. Although both glycolipids induce a similar cytokine response in sera of mice injected i.v., after i.m. injection, αGalCer induces a systemic cytokine response, whereas 7DW8-5 is locally trapped by CD1d expressed by dendritic cells (DCs) in draining lymph nodes (dLNs). Moreover, the i.m. coadministration of 7DW8-5 with IrPySpz results in the recruitment of DCs to dLNs and the activation and maturation of DCs. These events cause the potent adjuvant effect of 7DW8-5, resulting in the enhancement of the CD8(+) T cell response induced by IrPySpz and, ultimately, improved protection against malaria. Our study is the first to show that the colocalization of a CD1d-binding invariant NK T cell-stimulatory glycolipid and a vaccine, like radiation-attenuated sporozoites, in dLN-resident DCs upon i.m. conjoint administration governs the potency of the adjuvant effect of the glycolipid. Copyright © 2015 by The American Association of Immunologists, Inc.

  18. The Plasmodium serine-type SERA proteases display distinct expression patterns and non-essential in vivo roles during life cycle progression of the malaria parasite.

    Science.gov (United States)

    Putrianti, Elyzana D; Schmidt-Christensen, Anja; Arnold, Iris; Heussler, Volker T; Matuschewski, Kai; Silvie, Olivier

    2010-06-01

    Parasite proteases play key roles in several fundamental steps of the Plasmodium life cycle, including haemoglobin degradation, host cell invasion and parasite egress. Plasmodium exit from infected host cells appears to be mediated by a class of papain-like cysteine proteases called 'serine repeat antigens' (SERAs). A SERA subfamily, represented by Plasmodium falciparum SERA5, contains an atypical active site serine residue instead of a catalytic cysteine. Members of this SERAser subfamily are abundantly expressed in asexual blood stages, rendering them attractive drug and vaccine targets. In this study, we show by antibody localization and in vivo fluorescent tagging with the red fluorescent protein mCherry that the two P. berghei serine-type family members, PbSERA1 and PbSERA2, display differential expression towards the final stages of merozoite formation. Via targeted gene replacement, we generated single and double gene knockouts of the P. berghei SERAser genes. These loss-of-function lines progressed normally through the parasite life cycle, suggesting a specialized, non-vital role for serine-type SERAs in vivo. Parasites lacking PbSERAser showed increased expression of the cysteine-type PbSERA3. Compensatory mechanisms between distinct SERA subfamilies may thus explain the absence of phenotypical defect in SERAser disruptants, and challenge the suitability to develop potent antimalarial drugs based on specific inhibitors of Plasmodium serine-type SERAs.

  19. Developing Plasmodium vivax Resources for Liver Stage Study in the Peruvian Amazon Region.

    Science.gov (United States)

    Orjuela-Sanchez, Pamela; Villa, Zaira Hellen; Moreno, Marta; Tong-Rios, Carlos; Meister, Stephan; LaMonte, Gregory M; Campo, Brice; Vinetz, Joseph M; Winzeler, Elizabeth A

    2018-04-13

    To develop new drugs and vaccines for malaria elimination, it will be necessary to discover biological interventions, including small molecules that act against Plasmodium vivax exoerythrocytic forms. However, a robust in vitro culture system for P. vivax is still lacking. Thus, to study exoerythrocytic forms, researchers must have simultaneous access to fresh, temperature-controlled patient blood samples, as well as an anopheline mosquito colony. In addition, researchers must rely on native mosquito species to avoid introducing a potentially dangerous invasive species into a malaria-endemic region. Here, we report an in vitro culture system carried out on site in a malaria-endemic region for liver stage parasites of P. vivax sporozoites obtained from An. darlingi, the main malaria vector in the Americas. P. vivax sporozoites were obtained by dissection of salivary glands from infected An. darlingi mosquitoes and purified by Accudenz density gradient centrifugation. HC04 liver cells were exposed to P. vivax sporozoites and cultured up to 9 days. To overcome low P. vivax patient parasitemias, potentially lower mosquito vectorial capacity, and humid, nonsterile environmental conditions, a new antibiotic cocktail was included in tissue culture to prevent contamination. Culturing conditions supported exoerythrocytic (EEF) P. vivax liver stage growth up to 9 days and allowed for maturation into intrahepatocyte merosomes. Some of the identified small forms were resistant to atovaquone (1 μM) but sensitive to the phosphatidylinositol 4-kinase inhibitor, KDU691 (1 μM). This study reports a field-accessible EEF production process for drug discovery in a malaria-endemic site in which viable P. vivax sporozoites are used for drug studies using hepatocyte infection. Our data demonstrate that the development of meaningful, field-based resources for P. vivax liver stage drug screening and liver stage human malaria experimentation in the Amazon region is feasible.

  20. A constitutive pan-hexose permease for the Plasmodium life cycle and transgenic models for screening of antimalarial sugar analogs.

    Science.gov (United States)

    Blume, Martin; Hliscs, Marion; Rodriguez-Contreras, Dayana; Sanchez, Marco; Landfear, Scott; Lucius, Richard; Matuschewski, Kai; Gupta, Nishith

    2011-04-01

    Glucose is considered essential for erythrocytic stages of the malaria parasite, Plasmodium falciparum. Importance of sugar and its permease for hepatic and sexual stages of Plasmodium, however, remains elusive. Moreover, increasing global resistance to current antimalarials necessitates the search for novel drugs. Here, we reveal that hexose transporter 1 (HT1) of Plasmodium berghei can transport glucose (K(m)~87 μM), mannose (K(i)~93 μM), fructose (K(i)~0.54 mM), and galactose (K(i)~5 mM) in Leishmania mexicana mutant and Xenopus laevis; and, therefore, is functionally equivalent to HT1 of P. falciparum (Glc, K(m)~175 μM; Man, K(i)~276 μM; Fru, K(i)~1.25 mM; Gal, K(i)~5.86 mM). Notably, a glucose analog, C3361, attenuated hepatic (IC(50)~15 μM) and ookinete development of P. berghei. The PbHT1 could be ablated during intraerythrocytic stages only by concurrent complementation with PbHT1-HA or PfHT1. Together; these results signify that PbHT1 and glucose are required for the entire life cycle of P. berghei. Accordingly, PbHT1 is expressed in the plasma membrane during all parasite stages. To permit a high-throughput screening of PfHT1 inhibitors and their subsequent in vivo assessment, we have generated Saccharomyces cerevisiae mutant expressing codon-optimized PfHT1, and a PfHT1-dependent Δpbht1 parasite strain. This work provides a platform to facilitate the development of drugs against malaria, and it suggests a disease-control aspect by reducing parasite transmission.

  1. Larval diet affects mosquito development and permissiveness to Plasmodium infection.

    Science.gov (United States)

    Linenberg, Inbar; Christophides, George K; Gendrin, Mathilde

    2016-12-02

    The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii. We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clarke's Pool Pellets and Nishikoi Fish Pellets, and one flaked diet, Tetramin Fish-Flakes. Larvae grow and develop faster and produce bigger adults when feeding on both types of pellets compared with flakes. This correlates with a higher microbiota load in pellet-fed larvae, in agreement with the known positive effect of the microbiota on mosquito development. Larval diet also significantly influences the prevalence and intensity of Plasmodium berghei infection in adults, whereby Nishikoi Fish Pellets-fed larvae develop into adults that are highly permissive to parasites and survive longer after infection. This correlates with a lower amount of Enterobacteriaceae in the midgut microbiota. Together, our results shed light on the influence of larval feeding on mosquito development, microbiota and vector competence; they also provide useful data for mosquito rearing.

  2. Enlightening the malaria parasite life cycle: bioluminescent Plasmodium in fundamental and applied research.

    Science.gov (United States)

    Siciliano, Giulia; Alano, Pietro

    2015-01-01

    The unicellular protozoan parasites of the genus Plasmodium impose on human health worldwide the enormous burden of malaria. The possibility to genetically modify several species of malaria parasites represented a major advance in the possibility to elucidate their biology and is now turning laboratory lines of transgenic Plasmodium into precious weapons to fight malaria. Amongst the various genetically modified plasmodia, transgenic parasite lines expressing bioluminescent reporters have been essential to unveil mechanisms of parasite gene expression and to develop in vivo imaging approaches in mouse malaria models. Mainly the human malaria parasite Plasmodium falciparum and the rodent parasite P. berghei have been engineered to express bioluminescent reporters in almost all the developmental stages of the parasite along its complex life cycle between the insect and the vertebrate hosts. Plasmodium lines expressing conventional and improved luciferase reporters are now gaining a central role to develop cell based assays in the much needed search of new antimalarial drugs and to open innovative approaches for both fundamental and applied research in malaria.

  3. Effects of the vascular endothelial growth factor receptor-2 (VEGFR-2) inhibitor SU5416 on in vitro cultures of Plasmodium falciparum

    DEFF Research Database (Denmark)

    Hempel, Casper; Hoyer, Nils; Staalsø, Trine

    2014-01-01

    BACKGROUND: Vascular endothelial growth factor (VEGF) is taken up by parasitized red blood cells during malaria and stimulates intra-erythrocytic growth of Plasmodium falciparum in vitro. The cause and consequence of this uptake is not understood. METHODS: Plasmodium falciparum was cultured......, SU5416, dose-dependently inhibited growth. None of the treatments reduced intracellular VEGF levels. Thus, the anti-parasitic effect of SU5416 seemed independent of VEGF uptake. SU5416 reduced phosphorylated tyrosine in parasitized red blood cells. Similarly, the broad-spectrum tyrosine kinase...... in vitro. Parasite growth and intracellular VEGF levels were assessed using flow cytometry. Intracellular VEGF was visualized by fluorescence immunocytochemistry. Phosphorylated tyrosine was measured by western blotting. In vivo assessment of intra-erythrocytic VEGF was performed in Plasmodium berghei ANKA...

  4. Immunolocalization of an enterotoxic glycoprotein exoantigen on the secretory organelles of Cryptosporidium parvum sporozoites

    Directory of Open Access Journals (Sweden)

    El-Shewy K.A.

    2004-06-01

    Full Text Available In this study, the fine ultrastructures of the secretory organelles of C. parvum sporozoites were demonstrated using transmission electron microscopy (TEM. Meanwhile, a previously identified enterotoxic 18-20 kDa copro-antigen (18-20 kDa CCA, associated with cryptosporidiosis in both human and calves, was isolated and immunolocalized on C. parvum sporozoites. Using immunoelectron microscopy and anti-18-20 kDa monospecific antibody demonstrated marked existence of the 18-20 kDa CCA on the apical organelles and at the trilaminar pellicles. An anterior extrusion of this protein was demonstrated around the excysted and released sporozoites. However, non excysted sporozoites did not show this protein. Affinity blotting, with biotinylated jacalin, demonstrated the O-linked oligosaccharide moiety of this protein. The potential role of this protein in the host cell invasion and/or gliding motility remains unelucidated. However, its enterotoxicity, location and secretory nature suggest that it may be a target for neutralization or invasion inhibition of Cryptosporidium.

  5. Macrophages facilitate the excystation and differentiation of Toxoplasma gondii sporozoites into tachyzoites following oocyst internalisation.

    Science.gov (United States)

    Freppel, Wesley; Puech, Pierre-Henri; Ferguson, David J P; Azas, Nadine; Dubey, Jitender P; Dumètre, Aurélien

    2016-09-19

    Toxoplasma gondii is a common parasite of humans and animals, which is transmitted via oocysts in cat faeces or tissue cysts in contaminated meat. The robust oocyst and sporocyst walls protect the infective sporozoites from deleterious external attacks including disinfectants. Upon oocyst acquisition, these walls lose their integrity to let the sporozoites excyst and invade host cells following a process that remains poorly understood. Given the resistance of the oocyst wall to digestive enzymes and the ability of oocysts to cause parenteral infections, the present study investigated the possible contribution of macrophages in supporting sporozoite excystation following oocyst internalisation. By using single cell micromanipulations, real-time and time-point imaging techniques, we demonstrated that RAW macrophages could interact rapidly with oocysts and engulfed them by remodelling of their actin cytoskeleton. Internalised oocysts were associated to macrophage acidic compartments and showed evidences of wall disruption. Sporozoites were observed in macrophages containing oocyst remnants or in new macrophages, giving rise to dividing tachyzoites. All together, these results highlight an unexpected role of phagocytic cells in processing T. gondii oocysts, in line with non-classical routes of infection, and open new perspectives to identify chemical factors that lead to oocyst wall disruption under physiological conditions.

  6. Macrophages facilitate the excystation and differentiation of Toxoplasma gondii sporozoites into tachyzoites following oocyst internalization

    Science.gov (United States)

    Toxoplasma gondii is a common parasite of humans and domestic animals, which is transmitted via oocysts in cat faeces or tissue cysts in contaminated meat. The oocyst and sporocyst walls are multilayered polymeric structures that protect the infective sporozoites from deleterious physical and chemic...

  7. of Plasmodium cynomolgi

    African Journals Online (AJOL)

    SERVER

    2007-11-19

    Nov 19, 2007 ... AMA-1 sequences implies a conserved function for this molecule across different species of. Plasmodium. ... knowledge of detailed structural organization is crucial in ... sional (3D) structure of a protein are of great assistance.

  8. The MB2 gene family of Plasmodium species has a unique combination of S1 and GTP-binding domains

    Directory of Open Access Journals (Sweden)

    Ogunjumo Oluwasanmi

    2004-06-01

    Full Text Available Abstract Background Identification and characterization of novel Plasmodium gene families is necessary for developing new anti-malarial therapeutics. The products of the Plasmodium falciparum gene, MB2, were shown previously to have a stage-specific pattern of subcellular localization and proteolytic processing. Results Genes homologous to MB2 were identified in five additional parasite species, P. knowlesi, P. gallinaceum, P. berghei, P. yoelii, and P. chabaudi. Sequence comparisons among the MB2 gene products reveal amino acid conservation of structural features, including putative S1 and GTP-binding domains, and putative signal peptides and nuclear localization signals. Conclusions The combination of domains is unique to this gene family and indicates that MB2 genes comprise a novel family and therefore may be a good target for drug development.

  9. The MB2 gene family of Plasmodium species has a unique combination of S1 and GTP-binding domains

    Science.gov (United States)

    Romero, Lisa C; Nguyen, Thanh V; Deville, Benoit; Ogunjumo, Oluwasanmi; James, Anthony A

    2004-01-01

    Background Identification and characterization of novel Plasmodium gene families is necessary for developing new anti-malarial therapeutics. The products of the Plasmodium falciparum gene, MB2, were shown previously to have a stage-specific pattern of subcellular localization and proteolytic processing. Results Genes homologous to MB2 were identified in five additional parasite species, P. knowlesi, P. gallinaceum, P. berghei, P. yoelii, and P. chabaudi. Sequence comparisons among the MB2 gene products reveal amino acid conservation of structural features, including putative S1 and GTP-binding domains, and putative signal peptides and nuclear localization signals. Conclusions The combination of domains is unique to this gene family and indicates that MB2 genes comprise a novel family and therefore may be a good target for drug development. PMID:15222903

  10. Antigen-displaying lipid-enveloped PLGA nanoparticles as delivery agents for a Plasmodium vivax malaria vaccine.

    Science.gov (United States)

    Moon, James J; Suh, Heikyung; Polhemus, Mark E; Ockenhouse, Christian F; Yadava, Anjali; Irvine, Darrell J

    2012-01-01

    The parasite Plasmodium vivax is the most frequent cause of malaria outside of sub-Saharan Africa, but efforts to develop viable vaccines against P. vivax so far have been inadequate. We recently developed pathogen-mimicking polymeric vaccine nanoparticles composed of the FDA-approved biodegradable polymer poly(lactide-co-glycolide) acid (PLGA) "enveloped" by a lipid membrane. In this study, we sought to determine whether this vaccine delivery platform could be applied to enhance the immune response against P. vivax sporozoites. A candidate malaria antigen, VMP001, was conjugated to the lipid membrane of the particles, and an immunostimulatory molecule, monophosphoryl lipid A (MPLA), was incorporated into the lipid membranes, creating pathogen-mimicking nanoparticle vaccines (VMP001-NPs). Vaccination with VMP001-NPs promoted germinal center formation and elicited durable antigen-specific antibodies with significantly higher titers and more balanced Th1/Th2 responses in vivo, compared with vaccines composed of soluble protein mixed with MPLA. Antibodies raised by NP vaccinations also exhibited enhanced avidity and affinity toward the domains within the circumsporozoite protein implicated in protection and were able to agglutinate live P. vivax sporozoites. These results demonstrate that these VMP001-NPs are promising vaccines candidates that may elicit protective immunity against P. vivax sporozoites.

  11. Antigen-displaying lipid-enveloped PLGA nanoparticles as delivery agents for a Plasmodium vivax malaria vaccine.

    Directory of Open Access Journals (Sweden)

    James J Moon

    Full Text Available The parasite Plasmodium vivax is the most frequent cause of malaria outside of sub-Saharan Africa, but efforts to develop viable vaccines against P. vivax so far have been inadequate. We recently developed pathogen-mimicking polymeric vaccine nanoparticles composed of the FDA-approved biodegradable polymer poly(lactide-co-glycolide acid (PLGA "enveloped" by a lipid membrane. In this study, we sought to determine whether this vaccine delivery platform could be applied to enhance the immune response against P. vivax sporozoites. A candidate malaria antigen, VMP001, was conjugated to the lipid membrane of the particles, and an immunostimulatory molecule, monophosphoryl lipid A (MPLA, was incorporated into the lipid membranes, creating pathogen-mimicking nanoparticle vaccines (VMP001-NPs. Vaccination with VMP001-NPs promoted germinal center formation and elicited durable antigen-specific antibodies with significantly higher titers and more balanced Th1/Th2 responses in vivo, compared with vaccines composed of soluble protein mixed with MPLA. Antibodies raised by NP vaccinations also exhibited enhanced avidity and affinity toward the domains within the circumsporozoite protein implicated in protection and were able to agglutinate live P. vivax sporozoites. These results demonstrate that these VMP001-NPs are promising vaccines candidates that may elicit protective immunity against P. vivax sporozoites.

  12. Early Transcriptional Responses of HepG2-A 16 Liver Cells to Infection by Plasmodium falciparum Sporozoites

    Science.gov (United States)

    2011-07-29

    related protein complex 3, delta l subunit Solute carrier family 25, member 36 RAP! interacting factor homolog ( yeast ) Topoisomerase (DNA) I...virus (HCV) showed strong staining for glypican-3 (51), and yeast two-hybrid assays revealed that glypican-3 interacts with CD8l, a member of the...jenwithisuk, R., Coleman, R. E., Udomsangpetch, R., Cui, L., and Brewer , T. G. (2006) Am. f. Trap. Med. Hyg. 74, 708-715 18. Albuquerque, S. S., Carrel, C

  13. Vertebrate host specificity and experimental vectors of Plasmodium (Novyella) kempi sp. n. from the eastern wild turkey in Iowa.

    Science.gov (United States)

    Christensen, B M; Barnes, H J; Rowley, W A

    1983-07-01

    Vertebrate host specificity, experimental laboratory vectors, and a description of Plasmodium (Novyella) kempi sp. n. from eastern wild turkeys (Meleagris gallopavo silvestris Vieillot) in Iowa are presented. Plasmodium kempi is infective for domestic turkeys, bobwhites (Colinus virginianus), chukars (Alectoris graeca), guinea fowl (Numida meleagris), peacocks (Pavo cristatus), and canaries (Serinus canaria), produces a transient infection in mallards (Anas platyrhynchos) and domestic geese (Anser anser), but will not infect ring-necked pheasants (Phasianus colchicus), pigeons (Columba livia), Japanese quail (Coturnix coturnix), leghorn white chickens (Gallus gallus), or starlings (Sturnus vulgaris). Oocysts and (or) sporozoites were recovered from 68% (84/124) and 98% (60/61) of the Culex pipiens pipiens and C. tarsalis examined, respectively. Oocysts developed faster and sporozoites invaded the salivary glands sooner in C. tarsalis (6 days) than in C. p. pipiens (7 days). Culex tarsalis transmitted P. kempi more effectively than C. p. pipiens, although both species were capable of transmitting the parasite by natural feeding. Oocysts developed and sporozoites also were produced in C. restuans, but its ability to transmit the parasite was not determined. Aedes aegypti (Rockefeller strain) and A. triseriatus were refractive to P. kempi. Plasmodium kempi produces trophozoites with large refractile globules and fine cytoplasmic extensions, mature schizonts in the form of a condensed fan containing four to eight nuclei (usually 5), and elongate gametocytes with irregular borders. All stages are confined almost exclusively to mature erythrocytes, with no effect on host cell size or position of host cell nucleus. Plasmodium kempi is most similar morphologically to P. (Novyella) hexamerium and P. (Novyella) vaughani. It differs from P. hexamerium in having large refractile globules in trophozoites and immature schizonts, an inability to infect starlings, an absence of

  14. Enhanced depletion of glutathione and increased liver oxidative damage in aflatoxin-fed mice infected with Plasmodium berghei

    DEFF Research Database (Denmark)

    Ankrah, N A; Sittie, A; Addo, P G

    1995-01-01

    levels accompanied by a significant increase in serum cholinesterase and liver malonic dialdehyde levels in the mice fed aflatoxin compared with those in the control group. The results suggested that malaria parasites can enhance depletion of host glutathione and oxidative damage of the liver in mice fed...

  15. Plasmodium berghei ANKA: erythropoietin activates neural stem cells in an experimental cerebral malaria model

    DEFF Research Database (Denmark)

    Core, Andrew; Hempel, Casper; Kurtzhals, Jørgen A L

    2011-01-01

    investigated if EPO's neuroprotective effects include activation of endogenous neural stem cells (NSC). By using immunohistochemical markers of different NSC maturation stages, we show that EPO increased the number of nestin(+) cells in the dentate gyrus and in the sub-ventricular zone of the lateral...

  16. Shedding of the immunodominant P20 surface antigen of Eimeria bovis sporozoites.

    OpenAIRE

    Speer, C A; Whitmire, W M

    1989-01-01

    P20 is an immunodominant surface antigen of Eimeria bovis sporozoites. As parasites underwent merogony within cultured bovine monocytes and Madin-Darby bovine kidney (MDBK) cells, P20 appeared to be shed gradually by meronts and was absent in type 1 and 2 first-generation merozoites. Meronts of E. bovis appeared to shed P20 into the parasitophorous vacuole of bovine monocytes, whereas MDBK cells evidently released P20 into the culture medium or destroyed its antigenic determinant.

  17. Assessment of humoral immunity to Eimeria tenella sporozoites in chickens by ELISA

    Directory of Open Access Journals (Sweden)

    S. Saravanan

    2014-07-01

    Full Text Available Aim: To assess the humoral immune response of Eimeria tenella sporozoites in broiler chickens by a developed enzyme linked immunosorbent assay (ELISA and the efficacy in terms of bodyweight, lesion score and oocysts excretion in immunized broilers. Materials and Methods: Purified live E. tenella sporozoites were administered subcutaneously in neck region of broiler chickens in the early life (first week at different concentrations. The potency of the sporozoite vaccine as assessed by IgG levels and the performance in immunized broilers as assessed by body weight, lesion score and oocysts excretion in faeces after challenge with 10, 000 live E. tenella oocysts at 49 days of age were evaluated. Results: The chickens of group (T4 immunized with 20 µg of antigen on day 6 showed an increase in IgG levels (0.161±0.004 two weeks post immunization (PI peaking (0.399± 0.016 at 5 weeks PI. The mean weekly weight gain (g after challenge, at 56 days of age was high in T4 (148±4.751 g with a low mean lesion score (2.5±0.22 and mean oocyst output (x103 oocytes per gram (OPG in faeces (100.3± 45.72 when compared to unimmunised infected controls. Conclusion: An early but partial immune response against caecal coccidiosis could be achieved by immunization with E. tenella specific sporozoites in chickens of less than a week old. Moreover, the performance of immunized chickens as indicated by weight gain, lesion score and oocyst output was found to be superior to the unimmunized infected controls.

  18. Plasmodium and mononuclear phagocytes.

    Science.gov (United States)

    Mac-Daniel, Laura; Ménard, Robert

    2015-01-01

    Plasmodium, the causative agent of malaria, initially multiplies inside liver cells and then in successive cycles inside erythrocytes, causing the symptoms of the disease. In this review, we discuss interactions between the extracellular and intracellular forms of the Plasmodium parasite and innate immune cells in the mammalian host, with a special emphasis on mononuclear phagocytes. We overview here what is known about the innate immune cells that interact with parasites, mechanisms used by the parasite to evade them, and the protective or detrimental contribution of these interactions on parasite progression through its life cycle and pathology in the host. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Identification of sporozoite surface proteins and antigens of Eimeria nieschulzi (Apicomplexa)

    International Nuclear Information System (INIS)

    Tilley, M.; Upton, S.J.

    1990-01-01

    Sodium dodecyl sulfate polyacrylamide gel electrophoresis, immunoblotting, lectin binding, and 125 I surface labeling of sporozoites were used to probe sporozoites of the rat coccidian, Eimeria nieschulzi. Analysis of silver stained gels revealed greater than 50 bands. Surface iodination revealed about 14 well labeled, and about 10 weakly labeled but potential, surface proteins. The most heavily labeled surface proteins had molecular masses of 60, 53-54, 45, 28, 23-24, 17, 15, 14, 13, and 12 kD. Following electrophoresis and Western blotting, 2 of the 12 125I labeled lectin probes bound to two bands on the blots, which collectively indicated that two bands were glycosylated. Concanavalin A (ConA) specifically recognized a band at 53 kD, which may represent a surface glycoprotein, and a lectin derived from Osage orange (MPA) bound to a single band at 82-88 kD, that may also be a surface molecule. Immunoblotting using sera collected from rats inoculated orally with oocysts, as well as sera from mice hyperimmunized with sporozoites, revealed that many surface molecules appear to be immunogenic

  20. Manipulation of the Host Cell Membrane during Plasmodium Liver Stage Egress

    Directory of Open Access Journals (Sweden)

    Paul-Christian Burda

    2017-04-01

    Full Text Available A crucial step in the life cycle of Plasmodium parasites is the transition from the liver stage to the blood stage. Hepatocyte-derived merozoites reach the blood vessels of the liver inside host cell-derived vesicles called merosomes. The molecular basis of merosome formation is only partially understood. Here we show that Plasmodium berghei liver stage merozoites, upon rupture of the parasitophorous vacuole membrane, destabilize the host cell membrane (HCM and induce separation of the host cell actin cytoskeleton from the HCM. At the same time, the phospholipid and protein composition of the HCM appears to be substantially altered. This includes the loss of a phosphatidylinositol 4,5-bisphosphate (PIP2 reporter and the PIP2-dependent actin-plasma membrane linker ezrin from the HCM. Furthermore, transmembrane domain-containing proteins and palmitoylated and myristoylated proteins, as well as glycosylphosphatidylinositol-anchored proteins, lose their HCM localization. Collectively, these findings provide an explanation of HCM destabilization during Plasmodium liver stage egress and thereby contribute to our understanding of the molecular mechanisms that lead to merosome formation.

  1. Co-localization of a CD1d-binding glycolipid with a radiation-attenuated sporozoite vaccine in LN-resident DCs for a robust adjuvant effect

    Science.gov (United States)

    Li, Xiangming; Kawamura, Akira; Andrews, Chasity D.; Miller, Jessica L.; Wu, Douglass; Tsao, Tiffany; Zhang, Min; Oren, Deena; Padte, Neal N.; Porcelli, Steven A.; Wong, Chi-Huey; Kappe, Stefan H. I.; Ho, David D.; Tsuji, Moriya

    2015-01-01

    A CD1d-binding glycolipid, α-Galactosylceramide (αGalCer), activates invariant natural killer T (iNKT) cells and acts as an adjuvant. We previously identified a fluorinated phenyl ring-modified αGalCer analog, 7DW8-5, displaying nearly 100-fold stronger CD1d binding affinity. In the present study, 7DW8-5 was found to exert a more potent adjuvant effect than αGalCer for a vaccine based on radiation-attenuated sporozoites (RAS) of a rodent malaria parasite, Plasmodium yoelii, also referred to as irradiated P. yoelii sporozoites (IrPySpz). 7DW8-5 had a superb adjuvant effect only when the glycolipid and IrPySpz were conjointly administered intramuscularly (i.m.). Therefore, we evaluated the impact of distinctly different biodistribution patterns of αGalCer and 7DW8-5 on their respective adjuvant activities. While both glycolipids induce a similar cytokine response in sera of mice injected intravenously, after i.m. injection, αGalCer induces a systemic cytokine response, whereas 7DW8-5 is locally trapped by CD1d expressed by dendritic cells (DCs) in draining lymph nodes (dLNs). Moreover, the i.m. co-administration of 7DW8-5 with IrPySpz results in the recruitment of DCs to dLNs and the activation and maturation of DCs. These events cause the potent adjuvant effect of 7DW8-5, resulting in the enhancement of the CD8+ T-cell response induced by IrPySpz, and, ultimately, improved protection against malaria. Our study is the first to show that the co-localization of a CD1d-binding iNKT-cell stimulatory glycolipid and a vaccine, like RAS, in dLN-resident DCs upon i.m. conjoin administration governs the potency of the adjuvant effect of the glycolipid. PMID:26254338

  2. Bioinformatics analysis for structure and function of CPR of Plasmodium falciparum.

    Science.gov (United States)

    Fan, Zhigang; Zhang, Lingmin; Yan, Guogang; Wu, Qiang; Gan, Xiufeng; Zhong, Saifeng; Lin, Guifen

    2011-02-01

    To analyse the structure and function of NADPH-cytochrome p450 reductase (CYPOR or CPR) from Plasmodium falciparum (Pf), and to predict its' drug target and vaccine target. The structure, function, drug target and vaccine target of CPR from Plasmodium falciparum were analyzed and predicted by bioinformatics methods. PfCPR, which was older CPR, had close relationship with the CPR from other Plasmodium species, but it was distant from its hosts, such as Homo sapiens and Anopheles. PfCPR was located in the cellular nucleus of Plasmodium falciparum. 335aa-352aa and 591aa - 608aa were inserted the interior side of the nuclear membrane, while 151aa-265aa was located in the nucleolus organizer regions. PfCPR had 40 function sites and 44 protein-protein binding sites in amino acid sequence. The teriary structure of 1aa-700aa was forcep-shaped with wings. 15 segments of PfCPR had no homology with Homo sapien CPR and most were exposed on the surface of the protein. These segments had 25 protein-protein binding sites. While 13 other segments all possessed function sites. The evolution or genesis of Plasmodium falciparum is earlier than those of Homo sapiens. PfCPR is a possible resistance site of antimalarial drug and may involve immune evasion, which is associated with parasite of sporozoite in hepatocytes. PfCPR is unsuitable as vaccine target, but it has at least 13 ideal drug targets. Copyright © 2011 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  3. Activation of the hypnozoite: a part of Plasmodium vivax life cycle and survival.

    Science.gov (United States)

    Hulden, Lena; Hulden, Larry

    2011-04-16

    Plasmodium vivax is the most widespread malaria parasite. It has a dormant stage in the human liver, which makes it difficult to eradicate. It is proposed that a relapse of vivax malaria, besides being genetically determined by the specific strain, is induced by the bites of uninfected vectors. The dormant stage maximizes the possibility for the parasite to reach the vector for sexual reproduction. The advantage would increase if the parasite was able to detect the presence of a new generation of vectors. The sporozoites function both in the vector and in the human hosts. They invade the cells of the salivary gland in the vector and the hepatocytes in the human. Some of the sporozoites develop into hypnozoites in the human liver. It is suggested that the hypnozoite activates when it recognizes the same Anopheles specific protein, which it had previously recognized as a sporozoite to invade the salivary gland in the vector. Another possibility is that the hypnozoite activates upon the bodily reaction by the human on a bite by an Anopheles female. The connection between the relapse and a new generation of vectors can be documented by simultaneous monitoring of both parasitaemia in humans and the presence of uninfective/infective vectors in the same area with seasonal malaria transmission. Experimental studies are needed to find the saliva components, which trigger the relapse. Although P. cynomolgi in monkeys also has hypnozoites and relapses, testing with monkeys might be problematical. These live in a reasonably stable tropical environment where relapses cannot easily be linked to vectors. The importance of the trigger increases in unpredictable variations in the vector season. Artificial triggering of hypnozoites would make the medication more effective and resistance against a protein that the parasite itself uses during its life cycle would not develop. In areas with seasonal vivax malaria it could be used locally for eradication.

  4. Force Spectroscopy of the Plasmodium falciparum Vaccine Candidate Circumsporozoite Protein Suggests a Mechanically Pliable Repeat Region.

    Science.gov (United States)

    Patra, Aditya Prasad; Sharma, Shobhona; Ainavarapu, Sri Rama Koti

    2017-02-10

    The most effective vaccine candidate of malaria is based on the Plasmodium falciparum circumsporozoite protein (CSP), a major surface protein implicated in the structural strength, motility, and immune evasion properties of the infective sporozoites. It is suspected that reversible conformational changes of CSP are required for infection of the mammalian host, but the detailed structure and dynamic properties of CSP remain incompletely understood, limiting our understanding of its function in the infection. Here, we report the structural and mechanical properties of the CSP studied using single-molecule force spectroscopy on several constructs, one including the central region of CSP, which is rich in NANP amino acid repeats (CSP rep ), and a second consisting of a near full-length sequence without the signal and anchor hydrophobic domains (CSP ΔHP ). Our results show that the CSP rep is heterogeneous, with 40% of molecules requiring virtually no mechanical force to unfold (<10 piconewtons (pN)), suggesting that these molecules are mechanically compliant and perhaps act as entropic springs, whereas the remaining 60% are partially structured with low mechanical resistance (∼70 pN). CSP ΔHP having multiple force peaks suggests specifically folded domains, with two major populations possibly indicating the open and collapsed forms. Our findings suggest that the overall low mechanical resistance of the repeat region, exposed on the outer surface of the sporozoites, combined with the flexible full-length conformations of CSP, may provide the sporozoites not only with immune evasion properties, but also with lubricating capacity required during its navigation through the mosquito and vertebrate host tissues. We anticipate that these findings would further assist in the design and development of future malarial vaccines. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Stage-Specific Changes in Plasmodium Metabolism Required for Differentiation and Adaptation to Different Host and Vector Environments.

    Science.gov (United States)

    Srivastava, Anubhav; Philip, Nisha; Hughes, Katie R; Georgiou, Konstantina; MacRae, James I; Barrett, Michael P; Creek, Darren J; McConville, Malcolm J; Waters, Andrew P

    2016-12-01

    Malaria parasites (Plasmodium spp.) encounter markedly different (nutritional) environments during their complex life cycles in the mosquito and human hosts. Adaptation to these different host niches is associated with a dramatic rewiring of metabolism, from a highly glycolytic metabolism in the asexual blood stages to increased dependence on tricarboxylic acid (TCA) metabolism in mosquito stages. Here we have used stable isotope labelling, targeted metabolomics and reverse genetics to map stage-specific changes in Plasmodium berghei carbon metabolism and determine the functional significance of these changes on parasite survival in the blood and mosquito stages. We show that glutamine serves as the predominant input into TCA metabolism in both asexual and sexual blood stages and is important for complete male gametogenesis. Glutamine catabolism, as well as key reactions in intermediary metabolism and CoA synthesis are also essential for ookinete to oocyst transition in the mosquito. These data extend our knowledge of Plasmodium metabolism and point towards possible targets for transmission-blocking intervention strategies. Furthermore, they highlight significant metabolic differences between Plasmodium species which are not easily anticipated based on genomics or transcriptomics studies and underline the importance of integration of metabolomics data with other platforms in order to better inform drug discovery and design.

  6. Dual RNAseq shows the human mucosal immunity protein, MUC13, is a hallmark of Plasmodium exoerythrocytic infection

    KAUST Repository

    LaMonte, Gregory; Orjuela-Sanchez, Pamela; Wang, Lawrence; Li, Shangzhong; Swann, Justine; Cowell, Annie; Zou, Bing Yu; Abdel- Haleem Mohamed, Alyaa; Villa-Galarce, Zaira; Moreno, Marta; Tong-Rios, Carlos; Vinetz, Joseph; Lewis, Nathan; Winzeler, Elizabeth A

    2017-01-01

    The exoerythrocytic stage of Plasmodium malaria infection is a critical window for prophylactic intervention. Using a genome-wide dual RNA sequencing of flow-sorted infected and uninfected hepatoma cells we identify the human mucosal immunity gene, Mucin13 (MUC13), as strongly upregulated during Plasmodium exoerythrocytic hepatic-stage infection. We confirm that MUC13 expression is upregulated in hepatoma cell lines and primary hepatocytes. In immunofluorescence assays, host MUC13 protein expression distinguishes infected cells from adjacent uninfected cells and shows similar colocalization with parasite biomarkers such as UIS4 and HSP70. We further show that localization patterns are species independent, distinguishing both P. berghei and P. vivax infected cells, and that MUC13 can be used to identify compounds that inhibit parasite replication in hepatocytes across all Human-infecting Plasmodium species. This data presents a novel interface of host-parasite interactions in Plasmodium, in that a component of host mucosal immunity is reprogrammed to assist the progression of infection.

  7. Stage-Specific Changes in Plasmodium Metabolism Required for Differentiation and Adaptation to Different Host and Vector Environments.

    Directory of Open Access Journals (Sweden)

    Anubhav Srivastava

    2016-12-01

    Full Text Available Malaria parasites (Plasmodium spp. encounter markedly different (nutritional environments during their complex life cycles in the mosquito and human hosts. Adaptation to these different host niches is associated with a dramatic rewiring of metabolism, from a highly glycolytic metabolism in the asexual blood stages to increased dependence on tricarboxylic acid (TCA metabolism in mosquito stages. Here we have used stable isotope labelling, targeted metabolomics and reverse genetics to map stage-specific changes in Plasmodium berghei carbon metabolism and determine the functional significance of these changes on parasite survival in the blood and mosquito stages. We show that glutamine serves as the predominant input into TCA metabolism in both asexual and sexual blood stages and is important for complete male gametogenesis. Glutamine catabolism, as well as key reactions in intermediary metabolism and CoA synthesis are also essential for ookinete to oocyst transition in the mosquito. These data extend our knowledge of Plasmodium metabolism and point towards possible targets for transmission-blocking intervention strategies. Furthermore, they highlight significant metabolic differences between Plasmodium species which are not easily anticipated based on genomics or transcriptomics studies and underline the importance of integration of metabolomics data with other platforms in order to better inform drug discovery and design.

  8. Dual RNAseq shows the human mucosal immunity protein, MUC13, is a hallmark of Plasmodium exoerythrocytic infection

    KAUST Repository

    LaMonte, Gregory

    2017-10-03

    The exoerythrocytic stage of Plasmodium malaria infection is a critical window for prophylactic intervention. Using a genome-wide dual RNA sequencing of flow-sorted infected and uninfected hepatoma cells we identify the human mucosal immunity gene, Mucin13 (MUC13), as strongly upregulated during Plasmodium exoerythrocytic hepatic-stage infection. We confirm that MUC13 expression is upregulated in hepatoma cell lines and primary hepatocytes. In immunofluorescence assays, host MUC13 protein expression distinguishes infected cells from adjacent uninfected cells and shows similar colocalization with parasite biomarkers such as UIS4 and HSP70. We further show that localization patterns are species independent, distinguishing both P. berghei and P. vivax infected cells, and that MUC13 can be used to identify compounds that inhibit parasite replication in hepatocytes across all Human-infecting Plasmodium species. This data presents a novel interface of host-parasite interactions in Plasmodium, in that a component of host mucosal immunity is reprogrammed to assist the progression of infection.

  9. Plasmodium falciparum malaria

    African Journals Online (AJOL)

    Durrheim, Karen Barnes. Objectives. To assess the therapeutic efficacy of sulfadoxine- pyrimethamine (SP) after 5 years of use as first-line treatment of uncomplicated Plasmodium falciparum malaria, and thus guide the selection of artemisinin-based combination therapy in Mpumalanga, South Africa. Design. An open-label ...

  10. Plasmodium vivax thrombospondin related adhesion protein: immunogenicity and protective efficacy in rodents and Aotus monkeys

    Directory of Open Access Journals (Sweden)

    Angélica Castellanos

    2007-06-01

    Full Text Available The thrombospondin related adhesion protein (TRAP is a malaria pre-erythrocytic antigen currently pursued as malaria vaccine candidate to Plasmodium falciparum. In this study, a long synthetic peptide (LSP representing a P. vivax TRAP fragment involved in hepatocyte invasion was formulated in both Freund and Montanide ISA 720 adjutants and administered by IM and subcutaneous routes to BALB/c mice and Aotus monkeys. We measured specific humoral immune responses in both animal species and performed a sporozoite challenge in Aotus monkeys to assess the protective efficacy of the vaccine. After immunization both mice and Aotus seroconverted as shown by ELISA, and the specific anti-peptide antibodies cross reacted with the parasite in IFAT assays. Only two out of six immunized animals became infected after P. vivax sporozoite challenge as compared with four out of six animals from the control group. These results suggest that this TRAP fragment has protective potential against P. vivax malaria and deserves further studies as vaccine candidate.

  11. Immunogenicity and in vitro Protective Efficacy of a Recombinant Multistage Plasmodium falciparum Candidate Vaccine

    Science.gov (United States)

    Shi, Ya Ping; Hasnain, Seyed E.; Sacci, John B.; Holloway, Brian P.; Fujioka, Hisashi; Kumar, Nirbhay; Wohlhueter, Robert; Hoffman, Stephen L.; Collins, William E.; Lal, Altaf A.

    1999-02-01

    Compared with a single-stage antigen-based vaccine, a multistage and multivalent Plasmodium falciparum vaccine would be more efficacious by inducing "multiple layers" of immunity. We have constructed a synthetic gene that encodes for 12 B cell, 6 T cell proliferative, and 3 cytotoxic T lymphocyte epitopes derived from 9 stage-specific P. falciparum antigens corresponding to the sporozoite, liver, erythrocytic asexual, and sexual stages. The gene was expressed in the baculovirus system, and a 41-kDa antigen, termed CDC/NIIMALVAC-1, was purified. Immunization in rabbits with the purified protein in the presence of different adjuvants generated antibody responses that recognized vaccine antigen, linear peptides contained in the vaccine, and all stages of P. falciparum. In vitro assays of protection revealed that the vaccine-elicited antibodies strongly inhibited sporozoite invasion of hepatoma cells and growth of blood-stage parasites in the presence of monocytes. These observations demonstrate that a multicomponent, multistage malaria vaccine can induce immune responses that inhibit parasite development at multiple stages. The rationale and approach used in the development of a multicomponent P. falciparum vaccine will be useful in the development of a multispecies human malaria vaccine and vaccines against other infectious diseases.

  12. Three members of the 6-cys protein family of Plasmodium play a role in gamete fertility.

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    Melissa R van Dijk

    2010-04-01

    Full Text Available The process of fertilization is critically dependent on the mutual recognition of gametes and in Plasmodium, the male gamete surface protein P48/45 is vital to this process. This protein belongs to a family of 10 structurally related proteins, the so called 6-cys family. To identify the role of additional members of this family in Plasmodium fertilisation, we performed genetic and functional analysis on the five members of the 6-cys family that are transcribed during the gametocyte stage of P. berghei. This analysis revealed that in addition to P48/45, two members (P230 and P47 also play an essential role in the process of parasite fertilization. Mating studies between parasites lacking P230, P48/45 or P47 demonstrate that P230, like P48/45, is a male fertility factor, consistent with the previous demonstration of a protein complex containing both P48/45 and P230. In contrast, disruption of P47 results in a strong reduction of female fertility, while males remain unaffected. Further analysis revealed that gametes of mutants lacking expression of p48/45 or p230 or p47 are unable to either recognise or attach to each other. Disruption of the paralog of p230, p230p, also specifically expressed in gametocytes, had no observable effect on fertilization. These results indicate that the P. berghei 6-cys family contains a number of proteins that are either male or female specific ligands that play an important role in gamete recognition and/or attachment. The implications of low levels of fertilisation that exist even in the absence of these proteins, indicating alternative pathways of fertilisation, as well as positive selection acting on these proteins, are discussed in the context of targeting these proteins as transmission blocking vaccine candidates.

  13. Interferon-γ, a valuable surrogate marker of Plasmodium falciparum pre-erythrocytic stages protective immunity

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    BenMohamed Lbachir

    2011-02-01

    Full Text Available Abstract Immunity against the pre-erythrocytic stages of malaria is the most promising, as it is strong and fully sterilizing. Yet, the underlying immune effectors against the human Plasmodium falciparum pre-erythrocytic stages remain surprisingly poorly known and have been little explored, which in turn prevents any rational vaccine progress. Evidence that has been gathered in vitro and in vivo, in higher primates and in humans, is reviewed here, emphasizing the significant role of IFN-γ, either as a critical immune mediator or at least as a valuable surrogate marker of protection. One may hope that these results will trigger investigations in volunteers immunized either by optimally irradiated or over-irradiated sporozoites, to quickly delineate better surrogates of protection, which are essential for the development of a successful malaria vaccine.

  14. Characterization of mitochondrion-targeted GTPases in Plasmodium falciparum.

    Science.gov (United States)

    Gupta, Kirti; Gupta, Ankit; Haider, Afreen; Habib, Saman

    2018-04-12

    Ribosome assembly is critical for translation and regulating the response to cellular events and requires a complex interplay of ribosomal RNA and proteins with assembly factors. We investigated putative participants in the biogenesis of the reduced organellar ribosomes of Plasmodium falciparum and identified homologues of two assembly GTPases - EngA and Obg that were found in mitochondria. Both are indispensable in bacteria and P. berghei EngA is among the 'essential' parasite blood stage proteins identified recently. PfEngA and PfObg1 interacted with parasite mitoribosomes in vivo. GTP stimulated PfEngA interaction with the 50S subunit of Escherichia coli surrogate ribosomes. Although PfObg1-ribosome interaction was independent of nucleotide binding, GTP hydrolysis by PfObg1 was enhanced upon ribosomal association. An additional function for PfObg1 in mitochondrial DNA transactions was suggested by its specific interaction with the parasite mitochondrial genome in vivo. Deletion analysis revealed that the positively-charged OBG (spoOB-associated GTP-binding protein) domain mediates DNA-binding. A role for PfEngA in mitochondrial genotoxic stress response was indicated by its over-expression upon methyl methanesulfonate-induced DNA damage. PfEngA had lower sensitivity to an E. coli EngA inhibitor suggesting differences with bacterial counterparts. Our results show the involvement of two important GTPases in P. falciparum mitochondrial function, with the first confirmed localization of an EngA homologue in eukaryotic mitochondria.

  15. In vitro inhibition of Eimeria tenella sporozoite invasion into host cells by probiotics.

    Science.gov (United States)

    Hessenberger, S; Schatzmayr, G; Teichmann, K

    2016-10-15

    The aim was to study the effects of probiotics isolated from the intestinal tract of livestock animals on Eimeria tenella invasion into Madin-Darby bovine kidney (MDBK) cells in vitro. E. tenella sporozoites were purified and labeled with 5(6)-carboxyfluorescein diacetate N-succinimidyl ester before seeding on cell cultures, and invasion was evaluated by fluorescence microscopy. Two protocols (A and B) were used. In protocol A, Enterococcus faecium # 589 or Lactobacillus salivarius subsp. salivarius # 505 were added together with sporozoites to MDBK cell cultures and invasion was evaluated after incubation for approximately 20h. Viable, dead, or spent culture supernatants of probiotics were tested. In protocol B, viable probiotics were incubated with MDBK cells for one hour before sporozoites were added and invasion was evaluated after two more hours of incubation. Parasite invasion of viable, dead, or spent culture supernatant of E. faecium # 589 was assessed. Using protocol A, it was shown that parasite invasion was inhibited by viable (80%) or dead (75%) E. faecium # 589. While inhibition by viable L. salivarius subsp. salivarius # 505 was not valid at the highest concentration and not significant at the other test concentrations, dead cells inhibited parasite invasion up to 45%. Spent culture supernatants of both probiotics had no influence on parasite invasion. Using protocol B, it was shown that viable Bifidobacterium animalis subsp. animalis # 503, E. faecium # 497, E. faecium # 589, L. reuteri # 514, L. salivarius subsp. salivarius # 505, and Bacillus subtilis # 588 inhibited parasite invasion into MDBK cells up to 80%. Anticoccidial activity was strain-specific for E. faecium strains, and the strongest effect was shown by E. faecium # 589. Anticoccidial effects of some of the tested probiotics have already been shown in vivo, which makes them candidates to prevent coccidiosis. These findings have now been confirmed in vitro. The used parasite invasion

  16. Integrative omics analysis. A study based on Plasmodium falciparum mRNA and protein data.

    Science.gov (United States)

    Tomescu, Oana A; Mattanovich, Diethard; Thallinger, Gerhard G

    2014-01-01

    Technological improvements have shifted the focus from data generation to data analysis. The availability of large amounts of data from transcriptomics, protemics and metabolomics experiments raise new questions concerning suitable integrative analysis methods. We compare three integrative analysis techniques (co-inertia analysis, generalized singular value decomposition and integrative biclustering) by applying them to gene and protein abundance data from the six life cycle stages of Plasmodium falciparum. Co-inertia analysis is an analysis method used to visualize and explore gene and protein data. The generalized singular value decomposition has shown its potential in the analysis of two transcriptome data sets. Integrative Biclustering applies biclustering to gene and protein data. Using CIA, we visualize the six life cycle stages of Plasmodium falciparum, as well as GO terms in a 2D plane and interpret the spatial configuration. With GSVD, we decompose the transcriptomic and proteomic data sets into matrices with biologically meaningful interpretations and explore the processes captured by the data sets. IBC identifies groups of genes, proteins, GO Terms and life cycle stages of Plasmodium falciparum. We show method-specific results as well as a network view of the life cycle stages based on the results common to all three methods. Additionally, by combining the results of the three methods, we create a three-fold validated network of life cycle stage specific GO terms: Sporozoites are associated with transcription and transport; merozoites with entry into host cell as well as biosynthetic and metabolic processes; rings with oxidation-reduction processes; trophozoites with glycolysis and energy production; schizonts with antigenic variation and immune response; gametocyctes with DNA packaging and mitochondrial transport. Furthermore, the network connectivity underlines the separation of the intraerythrocytic cycle from the gametocyte and sporozoite stages

  17. Effect of the histaminergic antagonist over the pulmonary oedema growth in P. berghei - infected mice

    International Nuclear Information System (INIS)

    Martins, M.A.

    1985-01-01

    The involvement of histaminergic mechanisms in the pathogenesis of pulmonary oedema observed in p. berghei - infected mice was investigated. Histamine concentrations in plasma and whole blood of infected and normal mice were determined by radioenzymatic assay during the seven days of the infection. Elevated plasma and whole blood histamine levels were found at the last stages of infection (sixth day and seventh day) after intraperitoneal injection of parasitized erythrocytes, showing a close temporal correlation between the development of the oedema and the elevation of the circulating histamine concentrations. The participation of H 1 and H 2 receptors in the increase in vascular permeability (IVP) induced by histamine was also verified. (author)

  18. Protective antibody and CD8+ T-cell responses to the Plasmodium falciparum circumsporozoite protein induced by a nanoparticle vaccine.

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    Stephen A Kaba

    Full Text Available The worldwide burden of malaria remains a major public health problem due, in part, to the lack of an effective vaccine against the Plasmodium falciparum parasite. An effective vaccine will most likely require the induction of antigen specific CD8(+ and CD4(+ T-cells as well as long-lasting antibody responses all working in concert to eliminate the infection. We report here the effective modification of a self-assembling protein nanoparticle (SAPN vaccine previously proven effective in control of a P. berghei infection in a rodent model to now present B- and T-cell epitopes of the human malaria parasite P. falciparum in a platform capable of being used in human subjects.To establish the basis for a SAPN-based vaccine, B- and CD8(+ T-cell epitopes from the P. falciparum circumsporozoite protein (PfCSP and the universal CD4 T-helper epitope PADRE were engineered into a versatile small protein (∼125 amino acids that self-assembles into a spherical nanoparticle repetitively displaying the selected epitopes. P. falciparum epitope specific immune responses were evaluated in mice using a transgenic P. berghei malaria parasite of mice expressing the human malaria full-length P. falciparum circumsporozoite protein (Tg-Pb/PfCSP. We show that SAPN constructs, delivered in saline, can induce high-titer, long-lasting (1 year protective antibody and poly-functional (IFNγ(+, IL-2(+ long-lived central memory CD8(+ T-cells. Furthermore, we demonstrated that these Ab or CD8(+ T-cells can independently provide sterile protection against a lethal challenge of the transgenic parasites.The SAPN construct induces long-lasting antibody and cellular immune responses to epitope specific sequences of the P. falciparum circumsporozoite protein (PfCSP and prevents infection in mice by a transgenic P. berghei parasite displaying the full length PfCSP.

  19. Assessment and optimization of theileria parva sporozoite full-length p67 antigen expression in mammalian cells

    Science.gov (United States)

    Delivery of various forms of recombinant Theileria parva sporozoite antigen (p67) has been shown to elicit antibody responses in cattle capable of providing protection against East Coast fever, the clinical disease caused by T. parva. Previous formulations of full-length and shorter recombinant vers...

  20. Invasion of the intestinal tract by sporozoites of Eimeria coecicola and Eimeria intestinalis in naive and immune rabbits

    Czech Academy of Sciences Publication Activity Database

    Pakandl, Michal; Sewald, B.; Drouet-Viard, F.

    2006-01-01

    Roč. 98, č. 4 (2006), s. 310-316 ISSN 0932-0113 R&D Projects: GA ČR GA524/05/2328 Institutional research plan: CEZ:AV0Z60220518 Keywords : rabbit coccidia * sporozoites * intra- and extraintestinal migration Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 1.140, year: 2006

  1. UDP-galactose and acetyl-CoA transporters as Plasmodium multidrug resistance genes.

    Science.gov (United States)

    Lim, Michelle Yi-Xiu; LaMonte, Gregory; Lee, Marcus C S; Reimer, Christin; Tan, Bee Huat; Corey, Victoria; Tjahjadi, Bianca F; Chua, Adeline; Nachon, Marie; Wintjens, René; Gedeck, Peter; Malleret, Benoit; Renia, Laurent; Bonamy, Ghislain M C; Ho, Paul Chi-Lui; Yeung, Bryan K S; Chow, Eric D; Lim, Liting; Fidock, David A; Diagana, Thierry T; Winzeler, Elizabeth A; Bifani, Pablo

    2016-09-19

    A molecular understanding of drug resistance mechanisms enables surveillance of the effectiveness of new antimicrobial therapies during development and deployment in the field. We used conventional drug resistance selection as well as a regime of limiting dilution at early stages of drug treatment to probe two antimalarial imidazolopiperazines, KAF156 and GNF179. The latter approach permits the isolation of low-fitness mutants that might otherwise be out-competed during selection. Whole-genome sequencing of 24 independently derived resistant Plasmodium falciparum clones revealed four parasites with mutations in the known cyclic amine resistance locus (pfcarl) and a further 20 with mutations in two previously unreported P. falciparum drug resistance genes, an acetyl-CoA transporter (pfact) and a UDP-galactose transporter (pfugt). Mutations were validated both in vitro by CRISPR editing in P. falciparum and in vivo by evolution of resistant Plasmodium berghei mutants. Both PfACT and PfUGT were localized to the endoplasmic reticulum by fluorescence microscopy. As mutations in pfact and pfugt conveyed resistance against additional unrelated chemical scaffolds, these genes are probably involved in broad mechanisms of antimalarial drug resistance.

  2. Spatiotemporal and functional characterisation of the Plasmodium falciparum cGMP-dependent protein kinase.

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    Christine S Hopp

    Full Text Available Signalling by 3'-5'-cyclic guanosine monophosphate (cGMP exists in virtually all eukaryotes. In the apicomplexan parasite Plasmodium, the cGMP-dependent protein kinase (PKG has previously been reported to play a critical role in four key stages of the life cycle. The Plasmodium falciparum isoform (PfPKG is essential for the initiation of gametogenesis and for blood stage schizont rupture and work on the orthologue from the rodent malaria parasite P. berghei (PbPKG has shown additional roles in ookinete differentiation and motility as well as liver stage schizont development. In the present study, PfPKG expression and subcellular location in asexual blood stages was investigated using transgenic epitope-tagged PfPKG-expressing P. falciparum parasites. In Western blotting experiments and immunofluorescence analysis (IFA, maximal PfPKG expression was detected at the late schizont stage. While IFA suggested a cytosolic location, a degree of overlap with markers of the endoplasmic reticulum (ER was found and subcellular fractionation showed some association with the peripheral membrane fraction. This broad localisation is consistent with the notion that PfPKG, as with the mammalian orthologue, has numerous cellular substrates. This idea is further supported by the global protein phosphorylation pattern of schizonts which was substantially changed following PfPKG inhibition, suggesting a complex role for PfPKG during schizogony.

  3. Pretreatment with Cry1Ac Protoxin Modulates the Immune Response, and Increases the Survival of Plasmodium-Infected CBA/Ca Mice

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    Martha Legorreta-Herrera

    2010-01-01

    Full Text Available Malaria is a major global health problem that kills 1-2 million people each year. Despite exhaustive research, naturally acquired immunity is poorly understood. Cry1A proteins are potent immunogens with adjuvant properties and are able to induce strong cellular and humoral responses. In fact, it has been shown that administration of Cry1Ac protoxin alone or with amoebic lysates induces protection against the lethal infection caused by the protozoa Naegleria fowleri. In this work, we studied whether Cry1Ac is able to activate the innate immune response to induce protection against Plasmodium berghei ANKA (lethal and P. chabaudi AS (nonlethal parasites in CBA/Ca mice. Treatment with Cry1Ac induced protection against both Plasmodium species in terms of reduced parasitaemia, longer survival time, modulation of pro- and anti-inflammatory cytokines, and increased levels of specific antibodies against Plasmodium. Understanding how to boost innate immunity to Plasmodium infection should lead to immunologically based intervention strategies.

  4. Isolation and Characterization of Vaccine Candidate Genes Including CSP and MSP1 in Plasmodium yoelii.

    Science.gov (United States)

    Kim, Seon-Hee; Bae, Young-An; Seoh, Ju-Young; Yang, Hyun-Jong

    2017-06-01

    Malaria is an infectious disease affecting humans, which is transmitted by the bite of Anopheles mosquitoes harboring sporozoites of parasitic protozoans belonging to the genus Plasmodium . Despite past achievements to control the protozoan disease, malaria still remains a significant health threat up to now. In this study, we cloned and characterized the full-unit Plasmodium yoelii genes encoding merozoite surface protein 1 (MSP1), circumsporozoite protein (CSP), and Duffy-binding protein (DBP), each of which can be applied for investigations to obtain potent protective vaccines in the rodent malaria model, due to their specific expression patterns during the parasite life cycle. Recombinant fragments corresponding to the middle and C-terminal regions of PyMSP1 and PyCSP, respectively, displayed strong reactivity against P. yoelii -infected mice sera. Specific native antigens invoking strong humoral immune response during the primary and secondary infections of P. yoelii were also abundantly detected in experimental ICR mice. The low or negligible parasitemia observed in the secondary infected mice was likely to result from the neutralizing action of the protective antibodies. Identification of these antigenic proteins might provide the necessary information and means to characterize additional vaccine candidate antigens, selected solely on their ability to produce the protective antibodies.

  5. A transgenic Plasmodium falciparum NF54 strain that expresses GFP-luciferase throughout the parasite life cycle.

    Science.gov (United States)

    Vaughan, Ashley M; Mikolajczak, Sebastian A; Camargo, Nelly; Lakshmanan, Viswanathan; Kennedy, Mark; Lindner, Scott E; Miller, Jessica L; Hume, Jen C C; Kappe, Stefan H I

    2012-12-01

    Plasmodium falciparum is the pathogenic agent of the most lethal of human malarias. Transgenic P. falciparum parasites expressing luciferase have been created to study drug interventions of both asexual and sexual blood stages but luciferase-expressing mosquito stage and liver stage parasites have not been created which has prevented the easy quantification of mosquito stage development (e.g. for transmission blocking interventions) and liver stage development (for interventions that prevent infection). To overcome this obstacle, we have created a transgenic P. falciparum NF54 parasite that expresses a GFP-luciferase transgene throughout the life cycle. Luciferase expression is robust and measurable at all life cycle stages, including midgut oocyst, salivary gland sporozoites and liver stages, where in vivo development is easily measurable using humanized mouse infections in conjunction with an in vivo imaging system. This parasite reporter strain will accelerate testing of interventions against pre-erythrocytic life cycle stages. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Plasmodium ovale in Indonesia.

    Science.gov (United States)

    Baird, J K; Purnomo; Masbar, S

    1990-12-01

    We report 34 infections by Plasmodium ovale found among 15,806 blood film examinations taken between 1973 and 1989 from several sites in Indonesia. Twenty five of the P. ovale infections occurred in a single sample of 514 people living in Owi, Irian Jaya. We detected five additional infections at 3 other sites in Irian Jaya. Other infections by P. ovale occurred at two sites in West Flores. Another infection has already been reported from East Timor. Despite relatively frequent sampling of populations on Sumatra, Kalimantan, Java and Sulawesi, P. ovale has not been found on those islands. It appears that this parasite occurs only on the easternmost islands of the Indonesian archipelago where it is nonetheless a rare finding.

  7. Antimalarial activity of potential inhibitors of Plasmodium falciparum lactate dehydrogenase enzyme selected by docking studies.

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    Julia Penna-Coutinho

    Full Text Available The Plasmodium falciparum lactate dehydrogenase enzyme (PfLDH has been considered as a potential molecular target for antimalarials due to this parasite's dependence on glycolysis for energy production. Because the LDH enzymes found in P. vivax, P. malariae and P. ovale (pLDH all exhibit ∼90% identity to PfLDH, it would be desirable to have new anti-pLDH drugs, particularly ones that are effective against P. falciparum, the most virulent species of human malaria. Our present work used docking studies to select potential inhibitors of pLDH, which were then tested for antimalarial activity against P. falciparum in vitro and P. berghei malaria in mice. A virtual screening in DrugBank for analogs of NADH (an essential cofactor to pLDH and computational studies were undertaken, and the potential binding of the selected compounds to the PfLDH active site was analyzed using Molegro Virtual Docker software. Fifty compounds were selected based on their similarity to NADH. The compounds with the best binding energies (itraconazole, atorvastatin and posaconazole were tested against P. falciparum chloroquine-resistant blood parasites. All three compounds proved to be active in two immunoenzymatic assays performed in parallel using monoclonals specific to PfLDH or a histidine rich protein (HRP2. The IC(50 values for each drug in both tests were similar, were lowest for posaconazole (<5 µM and were 40- and 100-fold less active than chloroquine. The compounds reduced P. berghei parasitemia in treated mice, in comparison to untreated controls; itraconazole was the least active compound. The results of these activity trials confirmed that molecular docking studies are an important strategy for discovering new antimalarial drugs. This approach is more practical and less expensive than discovering novel compounds that require studies on human toxicology, since these compounds are already commercially available and thus approved for human use.

  8. Plasmodium chabaudi chabaudi malaria parasites can develop stable resistance to atovaquone with a mutation in the cytochrome b gene

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    Alves Ana C

    2010-05-01

    Full Text Available Abstract Background Plasmodium falciparum, has developed resistance to many of the drugs in use. The recommended treatment policy is now to use drug combinations. The atovaquone-proguanil (AP drug combination, is one of the treatment and prophylaxis options. Atovaquone (ATQ exerts its action by inhibiting plasmodial mitochondria electron transport at the level of the cytochrome bc1 complex. Plasmodium falciparum in vitro resistance to ATQ has been associated with specific point mutations in the region spanning codons 271-284 of the cytochrome b gene. ATQ -resistant Plasmodium yoelii and Plasmodium berghei lines have been obtained and resistant lines have amino acid mutations in their CYT b protein sequences. Plasmodium chabaudi model for studying drug-responses and drug-resistance selection is a very useful rodent malaria model but no ATQ resistant parasites have been reported so far. The aim of this study was to determine the ATQ sensitivity of the P. chabaudi clones, to select a resistant parasite line and to perform genotypic characterization of the cytb gene of these clones. Methods To select for ATQ resistance, Plasmodium. chabaudi chabaudi clones were exposed to gradually increasing concentrations of ATQ during several consecutive passages in mice. Plasmodium chabaudi cytb gene was amplified and sequenced. Results ATQ resistance was selected from the clone AS-3CQ. In order to confirm whether an heritable genetic mutation underlies the response of AS-ATQ to ATQ, the stability of the drug resistance phenotype in this clone was evaluated by measuring drug responses after (i multiple blood passages in the absence of the drug, (ii freeze/thawing of parasites in liquid nitrogen and (iii transmission through a mosquito host, Anopheles stephensi. ATQ resistance phenotype of the drug-selected parasite clone kept unaltered. Therefore, ATQ resistance in clone AS-ATQ is genetically encoded. The Minimum Curative Dose of AS-ATQ showed a six

  9. Entomologic investigation of Plasmodium knowlesi vectors in Kuala Lipis, Pahang, Malaysia

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    Jiram Adela I

    2012-06-01

    Full Text Available Abstract Background The first natural infection of Plasmodium knowlesi in humans was recorded in 1965 in peninsular Malaysia. Extensive research was then conducted and it was postulated that it was a rare incident and that simian malaria will not be easily transmitted to humans. However, at the turn of the 21st century, knowlesi malaria was prevalent throughout Southeast Asia and is life threatening. Thus, a longitudinal study was initiated to determine the vectors, their seasonal variation and preference to humans and macaques. Methods Monthly mosquito collections were carried out in Kuala Lipis, Pahang, peninsular Malaysia, using human-landing collection and monkey-baited traps at ground and canopy levels. All mosquitoes were identified and all anopheline mosquitoes were dissected and the gut and gland examined for oocysts and sporozoites. Nested polymerase chain reaction (PCR was conducted on positive samples, followed by sequencing of the csp gene. Results and discussion Anopheles cracens was the predominant mosquito biting humans as well as the macaques. It comprised 63.2% of the total collection and was the only species positive for sporozoites of P. knowlesi. It was exophagic and did not enter houses. Besides An. cracens, Anopheles kochi was also found in the monkey-bait trap. Both species preferred to bite monkeys at ground level compared to canopy. Conclusion Anopheles cracens, which belongs to the Dirus complex, Leucosphyrus subgroup, Leucosphyrus group of mosquitoes, has been confirmed to be the only vector for this site from Pahang during this study. It was the predominant mosquito at the study sites and with deforestation humans and villages are entering deeper in the forests, and nearer to the mosquitoes and macacques. The close association of humans with macaques and mosquitoes has led to zoonotic transmission of malaria.

  10. Entomologic investigation of Plasmodium knowlesi vectors in Kuala Lipis, Pahang, Malaysia.

    Science.gov (United States)

    Jiram, Adela I; Vythilingam, Indra; NoorAzian, Yusuf M; Yusof, Yusri M; Azahari, Abdul H; Fong, Mun-Yik

    2012-06-22

    The first natural infection of Plasmodium knowlesi in humans was recorded in 1965 in peninsular Malaysia. Extensive research was then conducted and it was postulated that it was a rare incident and that simian malaria will not be easily transmitted to humans. However, at the turn of the 21st century, knowlesi malaria was prevalent throughout Southeast Asia and is life threatening. Thus, a longitudinal study was initiated to determine the vectors, their seasonal variation and preference to humans and macaques. Monthly mosquito collections were carried out in Kuala Lipis, Pahang, peninsular Malaysia, using human-landing collection and monkey-baited traps at ground and canopy levels. All mosquitoes were identified and all anopheline mosquitoes were dissected and the gut and gland examined for oocysts and sporozoites. Nested polymerase chain reaction (PCR) was conducted on positive samples, followed by sequencing of the csp gene. Anopheles cracens was the predominant mosquito biting humans as well as the macaques. It comprised 63.2% of the total collection and was the only species positive for sporozoites of P. knowlesi. It was exophagic and did not enter houses. Besides An. cracens, Anopheles kochi was also found in the monkey-bait trap. Both species preferred to bite monkeys at ground level compared to canopy. Anopheles cracens, which belongs to the Dirus complex, Leucosphyrus subgroup, Leucosphyrus group of mosquitoes, has been confirmed to be the only vector for this site from Pahang during this study. It was the predominant mosquito at the study sites and with deforestation humans and villages are entering deeper in the forests, and nearer to the mosquitoes and macacques. The close association of humans with macaques and mosquitoes has led to zoonotic transmission of malaria.

  11. Release of hepatic Plasmodium yoelii merozoites into the pulmonary microvasculature.

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    Kerstin Baer

    2007-11-01

    Full Text Available Plasmodium undergoes one round of multiplication in the liver prior to invading erythrocytes and initiating the symptomatic blood phase of the malaria infection. Productive hepatocyte infection by sporozoites leads to the generation of thousands of merozoites capable of erythrocyte invasion. Merozoites are released from infected hepatocytes as merosomes, packets of hundreds of parasites surrounded by host cell membrane. Intravital microscopy of green fluorescent protein-expressing P. yoelii parasites showed that the majority of merosomes exit the liver intact, adapt a relatively uniform size of 12-18 microm, and contain 100-200 merozoites. Merosomes survived the subsequent passage through the right heart undamaged and accumulated in the lungs. Merosomes were absent from blood harvested from the left ventricle and from tail vein blood, indicating that the lungs effectively cleared the blood from all large parasite aggregates. Accordingly, merosomes were not detectable in major organs such as brain, kidney, and spleen. The failure of annexin V to label merosomes collected from hepatic effluent indicates that phosphatidylserine is not exposed on the surface of the merosome membrane suggesting the infected hepatocyte did not undergo apoptosis prior to merosome release. Merosomal merozoites continued to express green fluorescent protein and did not incorporate propidium iodide or YO-PRO-1 indicating parasite viability and an intact merosome membrane. Evidence of merosomal merozoite infectivity was provided by hepatic effluent containing merosomes being significantly more infective than blood with an identical low-level parasitemia. Ex vivo analysis showed that merosomes eventually disintegrate inside pulmonary capillaries, thus liberating merozoites into the bloodstream. We conclude that merosome packaging protects hepatic merozoites from phagocytic attack by sinusoidal Kupffer cells, and that release into the lung microvasculature enhances the

  12. Aspectos parasitários observados no local inoculado com esporozoitos de Plasmodium Gallinaceum

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    Lobato Paraense

    1943-06-01

    Full Text Available The following is a summary of the studies made on the development of Plasmodium gallinaceum sporozoites inoculated into normal chicks. Initially large numbers of laboratory reared Aëdes aegypti were fed on pullets heavily infected with gametocytes. Following the infectious meal the mosquitoes were kept on a diet of sugar and water syrup until the appearance of the sporozoites in the salivary glands. Normal chicks kept in hematophagous arthropod proof cages were then inoculated either by bite of the infected mosquitoes or by subcutaneous inoculations of salivary gland suspensions. By the first method ten mosquitoes fed to engorgement on each normal chick and were then sacrificed immediately afterwards to determine the sporozoite count. By the second method five pairs of salivary glands were dissected out at room temperature, triturated in physiological saline and inoculated subcutaneously. The epidermis and dermis at the site of inoculation were excised from six hours after inoculation to forty eight hours after appearance of the parasites in the blood stream and stretched out on filter paper with the epithelial surface downward. The dermis was then curretted. Slides were made of the scrapings consisting of connective tissue and epithelial cells of the basal layers which were fixed by metyl alcohol and stained with Giemsa for examination under the oil immersion lens. Skin fragments removed from normal chicks and from regions other than the site of inoculation in the infected chicks were used as controls. In these, only the normal histological aspect was ever encountered. In the biopsy made at the earliest period following inoculation clearly defined elongated forms with eight or more chromatin granules arranged in rosary formation were found. The author believes these to be products of the sporozoite evolution. Search for transition stages between these forms and sporozoites is planned in biopsies to be taken immediately following inoculation

  13. Plasmodium subtilisin-like protease 1 (SUB1): insights into the active-site structure, specificity and function of a pan-malaria drug target.

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    Withers-Martinez, Chrislaine; Suarez, Catherine; Fulle, Simone; Kher, Samir; Penzo, Maria; Ebejer, Jean-Paul; Koussis, Kostas; Hackett, Fiona; Jirgensons, Aigars; Finn, Paul; Blackman, Michael J

    2012-05-15

    Release of the malaria merozoite from its host erythrocyte (egress) and invasion of a fresh cell are crucial steps in the life cycle of the malaria pathogen. Subtilisin-like protease 1 (SUB1) is a parasite serine protease implicated in both processes. In the most dangerous human malarial species, Plasmodium falciparum, SUB1 has previously been shown to have several parasite-derived substrates, proteolytic cleavage of which is important both for egress and maturation of the merozoite surface to enable invasion. Here we have used molecular modelling, existing knowledge of SUB1 substrates, and recombinant expression and characterisation of additional Plasmodium SUB1 orthologues, to examine the active site architecture and substrate specificity of P. falciparum SUB1 and its orthologues from the two other major human malaria pathogens Plasmodium vivax and Plasmodium knowlesi, as well as from the rodent malaria species, Plasmodium berghei. Our results reveal a number of unusual features of the SUB1 substrate binding cleft, including a requirement to interact with both prime and non-prime side residues of the substrate recognition motif. Cleavage of conserved parasite substrates is mediated by SUB1 in all parasite species examined, and the importance of this is supported by evidence for species-specific co-evolution of protease and substrates. Two peptidyl alpha-ketoamides based on an authentic PfSUB1 substrate inhibit all SUB1 orthologues examined, with inhibitory potency enhanced by the presence of a carboxyl moiety designed to introduce prime side interactions with the protease. Our findings demonstrate that it should be possible to develop 'pan-reactive' drug-like compounds that inhibit SUB1 in all three major human malaria pathogens, enabling production of broad-spectrum antimalarial drugs targeting SUB1. Copyright © 2012 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  14. Computational and experimental analysis identified 6-diazo-5-oxonorleucine as a potential agent for treating infection by Plasmodium falciparum.

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    Plaimas, Kitiporn; Wang, Yulin; Rotimi, Solomon O; Olasehinde, Grace; Fatumo, Segun; Lanzer, Michael; Adebiyi, Ezekiel; König, Rainer

    2013-12-01

    Plasmodium falciparum (PF) is the most severe malaria parasite. It is developing resistance quickly to existing drugs making it indispensable to discover new drugs. Effective drugs have been discovered targeting metabolic enzymes of the parasite. In order to predict new drug targets, computational methods can be used employing database information of metabolism. Using this data, we performed recently a computational network analysis of metabolism of PF. We analyzed the topology of the network to find reactions which are sensitive against perturbations, i.e., when a single enzyme is blocked by drugs. We now used a refined network comprising also the host enzymes which led to a refined set of the five targets glutamyl-tRNA (gln) amidotransferase, hydroxyethylthiazole kinase, deoxyribose-phophate aldolase, pseudouridylate synthase, and deoxyhypusine synthase. It was shown elsewhere that glutamyl-tRNA (gln) amidotransferase of other microorganisms can be inhibited by 6-diazo-5-oxonorleucine. Performing a half maximal inhibitory concentration (IC50) assay, we showed, that 6-diazo-5-oxonorleucine is also severely affecting viability of PF in blood plasma of the human host. We confirmed this by an in vivo study observing Plasmodium berghei infected mice. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. A Knockout Screen of ApiAP2 Genes Reveals Networks of Interacting Transcriptional Regulators Controlling the Plasmodium Life Cycle.

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    Modrzynska, Katarzyna; Pfander, Claudia; Chappell, Lia; Yu, Lu; Suarez, Catherine; Dundas, Kirsten; Gomes, Ana Rita; Goulding, David; Rayner, Julian C; Choudhary, Jyoti; Billker, Oliver

    2017-01-11

    A family of apicomplexa-specific proteins containing AP2 DNA-binding domains (ApiAP2s) was identified in malaria parasites. This family includes sequence-specific transcription factors that are key regulators of development. However, functions for the majority of ApiAP2 genes remain unknown. Here, a systematic knockout screen in Plasmodium berghei identified ten ApiAP2 genes that were essential for mosquito transmission: four were critical for the formation of infectious ookinetes, and three were required for sporogony. We describe non-essential functions for AP2-O and AP2-SP proteins in blood stages, and identify AP2-G2 as a repressor active in both asexual and sexual stages. Comparative transcriptomics across mutants and developmental stages revealed clusters of co-regulated genes with shared cis promoter elements, whose expression can be controlled positively or negatively by different ApiAP2 factors. We propose that stage-specific interactions between ApiAP2 proteins on partly overlapping sets of target genes generate the complex transcriptional network that controls the Plasmodium life cycle. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  16. Paternal effect of the nuclear formin-like protein MISFIT on Plasmodium development in the mosquito vector.

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    Ellen S C Bushell

    2009-08-01

    Full Text Available Malaria parasites must undergo sexual and sporogonic development in mosquitoes before they can infect their vertebrate hosts. We report the discovery and characterization of MISFIT, the first protein with paternal effect on the development of the rodent malaria parasite Plasmodium berghei in Anopheles mosquitoes. MISFIT is expressed in male gametocytes and localizes to the nuclei of male gametocytes, zygotes and ookinetes. Gene disruption results in mutant ookinetes with reduced genome content, microneme defects and altered transcriptional profiles of putative cell cycle regulators, which yet successfully invade the mosquito midgut. However, developmental arrest ensues during the ookinete transformation to oocysts leading to malaria transmission blockade. Genetic crosses between misfit mutant parasites and parasites that are either male or female gamete deficient reveal a strict requirement for a male misfit allele. MISFIT belongs to the family of formin-like proteins, which are known regulators of the dynamic remodeling of actin and microtubule networks. Our data identify the ookinete-to-oocyst transition as a critical cell cycle checkpoint in Plasmodium development and lead us to hypothesize that MISFIT may be a regulator of cell cycle progression. This study offers a new perspective for understanding the male contribution to malaria parasite development in the mosquito vector.

  17. No miRNA were found in Plasmodium and the ones identified in erythrocytes could not be correlated with infection

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    Feng Le

    2008-03-01

    Full Text Available Abstract Background The transcriptional regulation of Plasmodium during its complex life cycle requires sequential activation and/or repression of different genetic programmes. MicroRNAs (miRNAs are a highly conserved class of non-coding RNAs that are important in regulating diverse cellular functions by sequence-specific inhibition of gene expression. What is know about double-stranded RNA-mediated gene silencing (RNAi and posttranscriptional gene silencing (PTGS in Plasmodium parasites entice us to speculate whether miRNAs can also function in Plasmodium-infected RBCs. Results Of 132 small RNA sequences, no Plasmodium-specific miRNAs have been found. However, a human miRNA, miR-451, was highly expressed, comprising approximately one third of the total identified miRNAs. Further analysis of miR-451 expression and malaria infection showed no association between the accumulation of miR-451 in Plasmodium falciparum-iRBCs, the life cycle stage of P. falciparum in the erythrocyte, or of P. berghei in mice. Moreover, treatment with an antisense oligonucleotide to miR-451 had no significant effect on the growth of the erythrocytic-stage P. falciparum. Methods Short RNAs from a mixed-stage of P. falciparum-iRBC were separated in a denaturing polyacrylamide gel and cloned into T vectors to create a cDNA library. Individual clones were then sequenced and further analysed by bioinformatics prediction to discover probable miRNAs in P. falciparum-iRBC. The association between miR-451 expression and the parasite were analysed by Northern blotting and antisense oligonucleotide (ASO of miR-451. Conclusion These results contribute to eliminate the probability of miRNAs in P. falciparum. The absence of miRNA in P. falciparum could be correlated with absence of argonaute/dicer genes. In addition, the miR-451 accumulation in Plasmodium-infected RBCs is independent of parasite infection. Its accumulation might be only the residual of erythroid differentiation or a

  18. Low prevalence of Plasmodium and absence of malaria transmission in Conakry, Guinea: prospects for elimination.

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    Kouassi, Bernard L; de Souza, Dziedzom K; Goepogui, Andre; Balde, Siradiou M; Diakité, Lamia; Sagno, Arsène; Djameh, Georgina I; Chammartin, Frédérique; Vounatsou, Penelope; Bockarie, Moses J; Utzinger, Jürg; Koudou, Benjamin G

    2016-03-18

    Over the past 15 years, mortality and morbidity due to malaria have been reduced substantially in sub-Saharan Africa and local elimination has been achieved in some settings. This study addresses the bio-ecology of larval and adult stages of malaria vectors, Plasmodium infection in Anopheles gambiae s.l. in the city of Conakry, Guinea, and discusses the prospect for malaria elimination. Water bodies were prospected to identify potential mosquito breeding sites for 6 days each in the dry season (January 2013) and in the rainy season (August 2013), using the dipping method. Adult mosquitoes were collected in 15 communities in the five districts of Conakry using exit traps and indoor spraying catches over a 1-year period (November 2012 to October 2013). Molecular approaches were employed for identification of Anopheles species, including An. coluzzii and An. gambiae s.s. Individual An. gambiae mosquitoes were tested for Plasmodium falciparum and P. vivax sporozoites using the VecTest™ malaria panel assay and an enzyme-linked immunosorbent assay. A systematic research of Ministry of Health statistical yearbooks was performed to determine malaria prevalence in children below the age of 5 years. Culex larval breeding sites were observed in large numbers throughout Conakry in both seasons. While Anopheles larval breeding sites were less frequent than Culex breeding sites, there was a high odds of finding An. gambiae mosquito larvae in agricultural sites during the rainy season. Over the 1-year study period, a total of 14,334 adult mosquitoes were collected; 14,135 Culex (98.6%) and 161 (1.1%) from the An. gambiae complex. One-hundred and twelve Anopheles mosquitoes, mainly collected from rice fields and gardens, were subjected to molecular analysis. Most of the mosquitoes were An. gambiae s.s. (n = 102; 91.1%) while the remaining 10 (8.9%) were An. melas. The molecular M form of An. gambiae s.s. was predominant (n = 89; 79.5%). The proportions of kdr genotype in the An

  19. Targeting the cell stress response of Plasmodium falciparum to overcome artemisinin resistance.

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    Con Dogovski

    2015-04-01

    Full Text Available Successful control of falciparum malaria depends greatly on treatment with artemisinin combination therapies. Thus, reports that resistance to artemisinins (ARTs has emerged, and that the prevalence of this resistance is increasing, are alarming. ART resistance has recently been linked to mutations in the K13 propeller protein. We undertook a detailed kinetic analysis of the drug responses of K13 wild-type and mutant isolates of Plasmodium falciparum sourced from a region in Cambodia (Pailin. We demonstrate that ART treatment induces growth retardation and an accumulation of ubiquitinated proteins, indicative of a cellular stress response that engages the ubiquitin/proteasome system. We show that resistant parasites exhibit lower levels of ubiquitinated proteins and delayed onset of cell death, indicating an enhanced cell stress response. We found that the stress response can be targeted by inhibiting the proteasome. Accordingly, clinically used proteasome inhibitors strongly synergize ART activity against both sensitive and resistant parasites, including isogenic lines expressing mutant or wild-type K13. Synergy is also observed against Plasmodium berghei in vivo. We developed a detailed model of parasite responses that enables us to infer, for the first time, in vivo parasite clearance profiles from in vitro assessments of ART sensitivity. We provide evidence that the clinical marker of resistance (delayed parasite clearance is an indirect measure of drug efficacy because of the persistence of unviable parasites with unchanged morphology in the circulation, and we suggest alternative approaches for the direct measurement of viability. Our model predicts that extending current three-day ART treatment courses to four days, or splitting the doses, will efficiently clear resistant parasite infections. This work provides a rationale for improving the detection of ART resistance in the field and for treatment strategies that can be employed in areas

  20. Proteomic analysis of protein interactions between Eimeria maxima sporozoites and chicken jejunal epithelial cells by shotgun LC-MS/MS.

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    Huang, Jingwei; Liu, Tingqi; Li, Ke; Song, Xiaokai; Yan, Ruofeng; Xu, Lixin; Li, Xiangrui

    2018-04-04

    Eimeria maxima initiates infection by invading the jejunal epithelial cells of chicken. However, the proteins involved in invasion remain unknown. The research of the molecules that participate in the interactions between E. maxima sporozoites and host target cells will fill a gap in our understanding of the invasion system of this parasitic pathogen. In the present study, chicken jejunal epithelial cells were isolated and cultured in vitro. Western blot was employed to analyze the soluble proteins of E. maxima sporozoites that bound to chicken jejunal epithelial cells. Co-immunoprecipitation (co-IP) assay was used to separate the E. maxima proteins that bound to chicken jejunal epithelial cells. Shotgun LC-MS/MS technique was used for proteomics identification and Gene Ontology was employed for the bioinformatics analysis. The results of Western blot analysis showed that four proteins bands from jejunal epithelial cells co-cultured with soluble proteins of E. maxima sporozoites were recognized by the positive sera, with molecular weights of 70, 90, 95 and 130 kDa. The co-IP dilutions were analyzed by shotgun LC-MS/MS. A total of 204 proteins were identified in the E. maxima protein database using the MASCOT search engine. Thirty-five proteins including microneme protein 3 and 7 had more than two unique peptide counts and were annotated using Gene Ontology for molecular function, biological process and cellular localization. The results revealed that of the 35 annotated peptides, 22 (62.86%) were associated with binding activity and 15 (42.86%) were involved in catalytic activity. Our findings provide an insight into the interaction between E. maxima and the corresponding host cells and it is important for the understanding of molecular mechanisms underlying E. maxima invasion.

  1. Genetic diversity of Plasmodium vivax and Plasmodium falciparum in Honduras.

    Science.gov (United States)

    Lopez, Ana Cecilia; Ortiz, Andres; Coello, Jorge; Sosa-Ochoa, Wilfredo; Torres, Rosa E Mejia; Banegas, Engels I; Jovel, Irina; Fontecha, Gustavo A

    2012-11-26

    Understanding the population structure of Plasmodium species through genetic diversity studies can assist in the design of more effective malaria control strategies, particularly in vaccine development. Central America is an area where malaria is a public health problem, but little is known about the genetic diversity of the parasite's circulating species. This study aimed to investigate the allelic frequency and molecular diversity of five surface antigens in field isolates from Honduras. Five molecular markers were analysed to determine the genotypes of Plasmodium vivax and Plasmodium falciparum from endemic areas in Honduras. Genetic diversity of ama-1, msp-1 and csp was investigated for P. vivax, and msp-1 and msp-2 for P. falciparum. Allelic frequencies were calculated and sequence analysis performed. A high genetic diversity was observed within Plasmodium isolates from Honduras. A different number of genotypes were elucidated: 41 (n = 77) for pvama-1; 23 (n = 84) for pvcsp; and 23 (n = 35) for pfmsp-1. Pvcsp sequences showed VK210 as the only subtype present in Honduran isolates. Pvmsp-1 (F2) was the most polymorphic marker for P. vivax isolates while pvama-1 was least variable. All three allelic families described for pfmsp-1 (n = 30) block 2 (K1, MAD20, and RO33), and both allelic families described for the central domain of pfmsp-2 (n = 11) (3D7 and FC27) were detected. However, K1 and 3D7 allelic families were predominant. All markers were randomly distributed across the country and no geographic correlation was found. To date, this is the most complete report on molecular characterization of P. vivax and P. falciparum field isolates in Honduras with regards to genetic diversity. These results indicate that P. vivax and P. falciparum parasite populations are highly diverse in Honduras despite the low level of transmission.

  2. Humanized HLA-DR4.RagKO.IL2RγcKO.NOD (DRAG) mice sustain the complex vertebrate life cycle of Plasmodium falciparum malaria.

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    Wijayalath, Wathsala; Majji, Sai; Villasante, Eileen F; Brumeanu, Teodor D; Richie, Thomas L; Casares, Sofia

    2014-09-30

    Malaria is a deadly infectious disease affecting millions of people in tropical and sub-tropical countries. Among the five species of Plasmodium parasites that infect humans, Plasmodium falciparum accounts for the highest morbidity and mortality associated with malaria. Since humans are the only natural hosts for P. falciparum, the lack of convenient animal models has hindered the understanding of disease pathogenesis and prompted the need of testing anti-malarial drugs and vaccines directly in human trials. Humanized mice hosting human cells represent new pre-clinical models for infectious diseases that affect only humans. In this study, the ability of human-immune-system humanized HLA-DR4.RagKO.IL2RγcKO.NOD (DRAG) mice to sustain infection with P. falciparum was explored. Four week-old DRAG mice were infused with HLA-matched human haematopoietic stem cells (HSC) and examined for reconstitution of human liver cells and erythrocytes. Upon challenge with infectious P. falciparum sporozoites (NF54 strain) humanized DRAG mice were examined for liver stage infection, blood stage infection, and transmission to Anopheles stephensi mosquitoes. Humanized DRAG mice reconstituted human hepatocytes, Kupffer cells, liver endothelial cells, and erythrocytes. Upon intravenous challenge with P. falciparum sporozoites, DRAG mice sustained liver to blood stage infection (average 3-5 parasites/microlitre blood) and allowed transmission to An. stephensi mosquitoes. Infected DRAG mice elicited antibody and cellular responses to the blood stage parasites and self-cured the infection by day 45 post-challenge. DRAG mice represent the first human-immune-system humanized mouse model that sustains the complex vertebrate life cycle of P. falciparum without the need of exogenous injection of human hepatocytes/erythrocytes or P. falciparum parasite adaptation. The ability of DRAG mice to elicit specific human immune responses to P. falciparum parasites may help deciphering immune correlates

  3. Sub-minute Phosphoregulation of Cell Cycle Systems during Plasmodium Gamete Formation

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    Brandon M. Invergo

    2017-11-01

    Full Text Available Summary: The transmission of malaria parasites to mosquitoes relies on the rapid induction of sexual reproduction upon their ingestion into a blood meal. Haploid female and male gametocytes become activated and emerge from their host cells, and the males enter the cell cycle to produce eight microgametes. The synchronized nature of gametogenesis allowed us to investigate phosphorylation signaling during its first minute in Plasmodium berghei via a high-resolution time course of the phosphoproteome. This revealed an unexpectedly broad response, with proteins related to distinct cell cycle events undergoing simultaneous phosphoregulation. We implicate several protein kinases in the process, and we validate our analyses on the plant-like calcium-dependent protein kinase 4 (CDPK4 and a homolog of serine/arginine-rich protein kinases (SRPK1. Mutants in these kinases displayed distinct phosphoproteomic disruptions, consistent with differences in their phenotypes. The results reveal the central role of protein phosphorylation in the atypical cell cycle regulation of a divergent eukaryote. : Invergo et al. measure a phosphoproteomic time course during a life cycle transition of a malarial parasite. They observed broad phosphoregulation on a sub-minute scale, including simultaneous regulation of replication- and mitosis-related proteins. Their analyses reveal conserved phosphorylation patterns, and they highlight functional roles of specific protein kinases during this process. Keywords: gametogenesis, proteomics, signal transduction, ARK2, CRK5

  4. Antimalarial activity of Syzygium guineense during early and established Plasmodium infection in rodent models.

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    Tadesse, Solomon Asmamaw; Wubneh, Zewdu Birhanu

    2017-01-05

    In Ethiopia, the leaves of Syzygium guineense have been found useful for the prevention and cure of malaria, and demonstrated antiplasmodial activity in vitro. Nevertheless, no scientific study has been conducted to confirm its antimalarial activity in vivo. Therefore, the objective of the study was to evaluate the antimalarial effect of Syzygium guineense leaf extract in mice. Inoculation of the study mice was carried out by using the malaria parasite, Plasmodium berghei. The plant extract was prepared at 200, 400 and 600 mg/kg. Chloroquine and distilled water was administered to the positive and negative control groups respectively. Parameters like parasitaemia, survival time and body weight were determined following standard tests (4-day suppressive, Rane's and repository tests). Syzygium guineense crude leaf extract displayed considerable (p activity in both the repository and curative tests. The extract also prevented body weight loss and prolonged survival date of mice significantly (P antimalarial activity in mice. The test substance was found to be safe with no observable signs of toxicity in the study mice. The results of the present work confirmed the in vitro antiplasmodial finding and traditional claims in vivo in mice. Therefore, Syzygium guineense could be regarded as a potential source to develop safe, effective and affordable antimalarial agent.

  5. Plasmodium vivax Malaria in Cambodia

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    Siv, Sovannaroth; Roca-Feltrer, Arantxa; Vinjamuri, Seshu Babu; Bouth, Denis Mey; Lek, Dysoley; Rashid, Mohammad Abdur; By, Ngau Peng; Popovici, Jean; Huy, Rekol; Menard, Didier

    2016-01-01

    The Cambodian National Strategic Plan for Elimination of Malaria aims to move step by step toward elimination of malaria across Cambodia with an initial focus on Plasmodium falciparum malaria before achieving elimination of all forms of malaria, including Plasmodium vivax in 2025. The emergence of artemisinin-resistant P. falciparum in western Cambodia over the last decade has drawn global attention to support the ultimate goal of P. falciparum elimination, whereas the control of P. vivax lags much behind, making the 2025 target gradually less achievable unless greater attention is given to P. vivax elimination in the country. The following review presents in detail the past and current situation regarding P. vivax malaria, activities of the National Malaria Control Program, and interventional measures applied. Constraints and obstacles that can jeopardize our efforts to eliminate this parasite species are discussed. PMID:27708187

  6. Modeling the dynamics of Plasmodium vivax infection and hypnozoite reactivation in vivo.

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    Adeshina I Adekunle

    2015-03-01

    Full Text Available The dynamics of Plasmodium vivax infection is characterized by reactivation of hypnozoites at varying time intervals. The relative contribution of new P. vivax infection and reactivation of dormant liver stage hypnozoites to initiation of blood stage infection is unclear. In this study, we investigate the contribution of new inoculations of P. vivax sporozoites to primary infection versus reactivation of hypnozoites by modeling the dynamics of P. vivax infection in Thailand in patients receiving treatment for either blood stage infection alone (chloroquine, or the blood and liver stages of infection (chloroquine + primaquine. In addition, we also analysed rates of infection in a study in Papua New Guinea (PNG where patients were treated with either artesunate, or artesunate + primaquine. Our results show that up to 96% of the P. vivax infection is due to hypnozoite reactivation in individuals living in endemic areas in Thailand. Similar analysis revealed the around 70% of infections in the PNG cohort were due to hypnozoite reactivation. We show how the age of the cohort, primaquine drug failure, and seasonality may affect estimates of the ratio of primary P. vivax infection to hypnozoite reactivation. Modeling of P. vivax primary infection and hypnozoite reactivation provides important insights into infection dynamics, and suggests that 90-96% of blood stage infections arise from hypnozoite reactivation. Major differences in infection kinetics between Thailand and PNG suggest the likelihood of drug failure in PNG.

  7. Short report: entomologic inoculation rates and Plasmodium falciparum malaria prevalence in Africa.

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    Beier, J C; Killeen, G F; Githure, J I

    1999-07-01

    Epidemiologic patterns of malaria infection are governed by environmental parameters that regulate vector populations of Anopheles mosquitoes. The intensity of malaria parasite transmission is normally expressed as the entomologic inoculation rate (EIR), the product of the vector biting rate times the proportion of mosquitoes infected with sporozoite-stage malaria parasites. Malaria transmission intensity in Africa is highly variable with annual EIRs ranging from 1,000 infective bites per person per year. Malaria control programs often seek to reduce morbidity and mortality due to malaria by reducing or eliminating malaria parasite transmission by mosquitoes. This report evaluates data from 31 sites throughout Africa to establish fundamental relationships between annual EIRs and the prevalence of Plasmodium falciparum malaria infection. The majority of sites fitted a linear relationship (r2 = 0.71) between malaria prevalence and the logarithm of the annual EIR. Some sites with EIRs 80%. The basic relationship between EIR and P. falciparum prevalence, which likely holds in east and west Africa, and across different ecologic zones, shows convincingly that substantial reductions in malaria prevalence are likely to be achieved only when EIRs are reduced to levels less than 1 infective bite per person per year. The analysis also highlights that the EIR is a more direct measure of transmission intensity than traditional measures of malaria prevalence or hospital-based measures of infection or disease incidence. As such, malaria field programs need to consider both entomologic and clinical assessments of the efficacy of transmission control measures.

  8. Absence of Plasmodium inui and Plasmodium cynomolgi, but detection of Plasmodium knowlesi and Plasmodium vivax infections in asymptomatic humans in the Betong division of Sarawak, Malaysian Borneo.

    Science.gov (United States)

    Siner, Angela; Liew, Sze-Tze; Kadir, Khamisah Abdul; Mohamad, Dayang Shuaisah Awang; Thomas, Felicia Kavita; Zulkarnaen, Mohammad; Singh, Balbir

    2017-10-17

    Plasmodium knowlesi, a simian malaria parasite, has become the main cause of malaria in Sarawak, Malaysian Borneo. Epidemiological data on malaria for Sarawak has been derived solely from hospitalized patients, and more accurate epidemiological data on malaria is necessary. Therefore, a longitudinal study of communities affected by knowlesi malaria was undertaken. A total of 3002 blood samples on filter paper were collected from 555 inhabitants of 8 longhouses with recently reported knowlesi malaria cases in the Betong Division of Sarawak, Malaysian Borneo. Each longhouse was visited bimonthly for a total of 10 times during a 21-month study period (Jan 2014-Oct 2015). DNA extracted from blood spots were examined by a nested PCR assay for Plasmodium and positive samples were then examined by nested PCR assays for Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, Plasmodium knowlesi, Plasmodium cynomolgi and Plasmodium inui. Blood films of samples positive by PCR were also examined by microscopy. Genus-specific PCR assay detected Plasmodium DNA in 9 out of 3002 samples. Species-specific PCR identified 7 P. knowlesi and one P. vivax. Malaria parasites were observed in 5 thick blood films of the PCR positive samples. No parasites were observed in blood films from one knowlesi-, one vivax- and the genus-positive samples. Only one of 7 P. knowlesi-infected individual was febrile and had sought medical treatment at Betong Hospital the day after sampling. The 6 knowlesi-, one vivax- and one Plasmodium-infected individuals were afebrile and did not seek any medical treatment. Asymptomatic human P. knowlesi and P. vivax malaria infections, but not P. cynomolgi and P. inui infections, are occurring within communities affected with malaria.

  9. Sterile protection against Plasmodium knowlesi in rhesus monkeys from a malaria vaccine: comparison of heterologous prime boost strategies.

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    George Jiang

    Full Text Available Using newer vaccine platforms which have been effective against malaria in rodent models, we tested five immunization regimens against Plasmodium knowlesi in rhesus monkeys. All vaccines included the same four P. knowlesi antigens: the pre-erythrocytic antigens CSP, SSP2, and erythrocytic antigens AMA1, MSP1. We used four vaccine platforms for prime or boost vaccinations: plasmids (DNA, alphavirus replicons (VRP, attenuated adenovirus serotype 5 (Ad, or attenuated poxvirus (Pox. These four platforms combined to produce five different prime/boost vaccine regimens: Pox alone, VRP/Pox, VRP/Ad, Ad/Pox, and DNA/Pox. Five rhesus monkeys were immunized with each regimen, and five Control monkeys received a mock vaccination. The time to complete vaccinations was 420 days. All monkeys were challenged twice with 100 P. knowlesi sporozoites given IV. The first challenge was given 12 days after the last vaccination, and the monkeys receiving the DNA/Pox vaccine were the best protected, with 3/5 monkeys sterilely protected and 1/5 monkeys that self-cured its parasitemia. There was no protection in monkeys that received Pox malaria vaccine alone without previous priming. The second sporozoite challenge was given 4 months after the first. All 4 monkeys that were protected in the first challenge developed malaria in the second challenge. DNA, VRP and Ad5 vaccines all primed monkeys for strong immune responses after the Pox boost. We discuss the high level but short duration of protection in this experiment and the possible benefits of the long interval between prime and boost.

  10. Plasmodium falciparum malaria challenge by the bite of aseptic Anopheles stephensi mosquitoes: results of a randomized infectivity trial.

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    Kirsten E Lyke

    2010-10-01

    Full Text Available Experimental infection of malaria-naïve volunteers by the bite of Plasmodium falciparum-infected mosquitoes is a preferred means to test the protective effect of malaria vaccines and drugs. The standard model relies on the bite of five infected mosquitoes to induce malaria. We examined the efficacy of malaria transmission using mosquitoes raised aseptically in compliance with current Good Manufacturing Practices (cGMPs.Eighteen adults aged 18-40 years were randomized to receive 1, 3 or 5 bites of Anopheles stephensi mosquitoes infected with the chloroquine-sensitive NF54 strain of P. falciparum. Seventeen participants developed malaria; fourteen occurring on Day 11. The mean prepatent period was 10.9 days (9-12 days. The geometric mean parasitemia was 15.7 parasites/µL (range: 4-70 by microscopy. Polymerase chain reaction (PCR detected parasites 3.1 (range: 0-4 days prior to microscopy. The geometric mean sporozoite load was 16,753 sporozoites per infected mosquito (range: 1,000-57,500. A 1-bite participant withdrew from the study on Day 13 post-challenge and was PCR and smear negative.The use of aseptic, cGMP-compliant P. falciparum-infected mosquitoes is safe, is associated with a precise prepatent period compared to the standard model and appears more efficient than the standard approach, as it led to infection in 100% (6/6 of volunteers exposed to three mosquito bites and 83% (5/6 of volunteers exposed to one mosquito bite.ClinicalTrials.gov NCT00744133.

  11. Identification of Plasmodium spp. in Neotropical primates of Maranhense Amazon in Northeast Brazil.

    Directory of Open Access Journals (Sweden)

    Mayra Araguaia Pereira Figueiredo

    Full Text Available In the Brazilian Amazon region, malaria caused by Plasmodium malariae is considered to be a zoonosis because of cross-transfer of the parasite between humans and Neotropical primates. To contribute information on this issue, we investigated occurrences of natural infection with Plasmodium sp. among Neotropical primates in the Maranhense Amazon (Amazon region of the state of Maranhão, in the northeastern region of Brazil. Blood samples were collected from 161 Neotropical primates of six species that were caught in an environmental reserve (Sítio Aguahy and from captive primates (CETAS-Wildlife Screening Center, municipality of São Luís, in Maranhão. Plasmodium sp. was diagnosed based on light microscopy, PCR, qPCR and LAMP for amplification of the 18S rRNA gene. Serum samples were also assayed by means of indirect immunofluorescence for IgG antibodies against P. malariae/P. brasilianum, P. falciparum and P. berghei. Parasites were detected through light microscopy on five slides from captive primates (four Sapajus spp. and one Callithrix jacchus. In the molecular tests, 34.16% (55/161 and 29.81% (48/161 of the animals sampled were positive in the qPCR and PCR assays, respectively. In the PCR, 47/48 animals were positive for P. malariae/P. brasilianum; of these, eight were free-living primates and 39 from CETAS, São Luís. One sample showed a band in the genus-specific reaction, but not in the second PCR reaction. Anti-P. malariae/P. brasilianum IgG antibodies were detected in four serum samples from Sapajus spp. in captivity. In this study, circulation of P. malariae/P. brasilianum in Neotropical primates was confirmed, with low levels of parasitemia and low levels of antibodies. The importance of these animals as reservoirs of human malaria in the region studied is still unknown. This scenario has an impact on control and elimination of malaria in this region.

  12. Avian Plasmodium in Eastern Austrian mosquitoes.

    Science.gov (United States)

    Schoener, Ellen; Uebleis, Sarah Susanne; Butter, Julia; Nawratil, Michaela; Cuk, Claudia; Flechl, Eva; Kothmayer, Michael; Obwaller, Adelheid G; Zechmeister, Thomas; Rubel, Franz; Lebl, Karin; Zittra, Carina; Fuehrer, Hans-Peter

    2017-09-29

    Insect vectors, namely mosquitoes (Diptera: Culicidae), are compulsory for malaria parasites (Plasmodium spp.) to complete their life cycle. Despite this, little is known about vector competence of different mosquito species for the transmission of avian malaria parasites. In this study, nested PCR was used to determine Plasmodium spp. occurrence in pools of whole individuals, as well as the diversity of mitochondrial cytochrome b gene sequences in wild-caught mosquitoes sampled across Eastern Austria in 2013-2015. A total of 45,749 mosquitoes in 2628 pools were collected, of which 169 pools (6.43%) comprising 9 mosquito species were positive for avian Plasmodium, with the majority of positives in mosquitoes of Culex pipiens s.l./Culex torrentium. Six different avian Plasmodium lineages were found, the most common were Plasmodium vaughani SYAT05, Plasmodium sp. Linn1 and Plasmodium relictum SGS1. In 2014, mosquitoes of the Culex pipiens complex were genetically identified and Culex pipiens f. pipiens presented with the highest number of avian Plasmodium positives (n = 37; 16.74%). Despite this, the minimum infection rate (MIR) was highest in Culex torrentium (5.36%) and Culex pipiens f. pipiens/f. molestus hybrids (5.26%). During 2014 and 2015, seasonal and annual changes in Plasmodium lineage distribution were also observed. In both years P. vaughani SYAT05 dominated at the beginning of the sampling period to be replaced later in the year by P. relictum SGS1 (2014) and Plasmodium sp. Linn1 (2015). This is the first large-scale study of avian Plasmodium parasites in Austrian mosquitoes. These results are of special interest, because molecular identification of the taxa of the Cx. pipiens complex and Cx. torrentium enabled the determination of Plasmodium prevalence in the different mosquito taxa and hybrids of this complex. Since pools of whole insects were used, it is not possible to assert any vector competence in any of the examined mosquitoes, but the results

  13. [Congenital malaria due to Plasmodium falciparum and Plasmodium malariae].

    Science.gov (United States)

    Zenz, W; Trop, M; Kollaritsch, H; Reinthaler, F

    2000-05-19

    Increasing tourism and growing numbers of immigrants from malaria-endemic countries are leading to a higher importation rate of rare tropical disorders in European countries. We describe, to the best of our knowledge, the first case of connatal malaria in Austria. The patient is the first child of a 24 year old mother who was born in Ghana and immigrated to Austria one and a half years before delivery. She did not stay in an endemic region during this period and did not show fever or any other signs of malaria. The boy was healthy for the first six weeks of his life. In the 8th week of life he was admitted to our hospital due to persistent fever of unknown origin. On physical examination he showed only mild splenomegaly. Routine laboratory testing revealed mild hemolytic anemia with a hemoglobin value of 8.3 g/l. In the blood smear Plasmodium falciparum and Plasmodium malariae were detected. Oral therapy with quinine hydrochloride was successful and blood smears became negative for Plasmodia within 6 days. This case shows that congenital malaria can occur in children of clinically healthy women who were born in malaria-endemic areas even one and a half year after they have immigrated to non-endemic regions.

  14. The periodicity of Plasmodium vivax and Plasmodium falciparum in Venezuela.

    Science.gov (United States)

    Grillet, María-Eugenia; El Souki, Mayida; Laguna, Francisco; León, José Rafael

    2014-01-01

    We investigated the periodicity of Plasmodium vivax and P. falciparum incidence in time-series of malaria data (1990-2010) from three endemic regions in Venezuela. In particular, we determined whether disease epidemics were related to local climate variability and regional climate anomalies such as the El Niño Southern Oscillation (ENSO). Malaria periodicity was found to exhibit unique features in each studied region. Significant multi-annual cycles of 2- to about 6-year periods were identified. The inter-annual variability of malaria cases was coherent with that of SSTs (ENSO), mainly at temporal scales within the 3-6 year periods. Additionally, malaria cases were intensified approximately 1 year after an El Niño event, a pattern that highlights the role of climate inter-annual variability in the epidemic patterns. Rainfall mediated the effect of ENSO on malaria locally. Particularly, rains from the last phase of the season had a critical role in the temporal dynamics of Plasmodium. The malaria-climate relationship was complex and transient, varying in strength with the region and species. By identifying temporal cycles of malaria we have made a first step in predicting high-risk years in Venezuela. Our findings emphasize the importance of analyzing high-resolution spatial-temporal data to better understand malaria transmission dynamics. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. The impact of livestock on the abundance, resting behaviour and sporozoite rate of malaria vectors in southern Tanzania.

    Science.gov (United States)

    Mayagaya, Valeriana S; Nkwengulila, Gamba; Lyimo, Issa N; Kihonda, Japheti; Mtambala, Hassan; Ngonyani, Hassan; Russell, Tanya L; Ferguson, Heather M

    2015-01-21

    Increases in the coverage of long-lasting insecticidal nets (LLINs) have significantly reduced the abundance of Anopheles gambiae sensu stricto in several African settings, leaving its more zoophagic sibling species Anopheles arabiensis as the primary vector. This study investigated the impact of livestock ownership at the household level on the ecology and malaria infection rate of vectors in an area of Tanzania where An. arabiensis accounts for most malaria transmission. Mosquito vectors were collected resting inside houses, animal sheds and in outdoor resting boxes at households with and without livestock over three years in ten villages of the Kilombero Valley, Tanzania. Additionally, the abundance and sporozoite rate of vectors attempting to bite indoors at these households was assessed as an index of malaria exposure. The mean abundance of An. gambiae s.l. biting indoors was similar at houses with and without livestock. In all years but one, the relative proportion of An. arabiensis within the An. gambiae s.l. species complex was higher at households with livestock. Livestock presence had a significant impact on malaria vector feeding and resting behaviour. Anopheles arabiensis were generally found resting in cattle sheds where livestock were present, and inside houses when absent. Correspondingly, the human blood index of An. arabiensis and An. funestus s.l. was significant reduced at households with livestock, whereas that of An. gambiae s.s. was unaffected. Whilst there was some evidence that sporozoite rates within the indoor-biting An. gambiae s.l population was significantly reduced at households with livestock, the significance of this effect varied depending on how background spatial variation was accounted for. These results confirm that the presence of cattle at the household level can significantly alter the local species composition, feeding and resting behaviour of malaria vectors. However, the net impact of this livestock-associated variation in

  16. In vitro synergistic effect of fluoroquinolone analogues in combination with artemisinin against Plasmodium falciparum; their antiplasmodial action in rodent malaria model.

    Science.gov (United States)

    Agarwal, Drishti; Sharma, Manish; Dixit, Sandeep K; Dutta, Roshan K; Singh, Ashok K; Gupta, Rinkoo D; Awasthi, Satish K

    2015-02-05

    Emergence of drug-resistant parasite strains has surfaced as a major obstacle in attempts to ameliorate malaria. Current treatment regimen of malaria relies on the concept of artemisinin-based combination therapy (ACT). Fluoroquinolone analogues, compounds 10, 12 and 18 were investigated for their anti-malarial interaction in combination with artemisinin in vitro, against Plasmodium falciparum 3D7 strain, employing fixed-ratio combination isobologram method. In addition, the efficacy of these compounds was evaluated intraperitoneally in BALB/c mice infected with chloroquine-resistant Plasmodium berghei ANKA strain in the Peters' four-day suppressive test. Promising results were obtained in the form of synergistic or additive interactions. Compounds 10 and 12 were found to have highly synergistic interactions with artemisinin. Antiplasmodial effect was further verified by the convincing ED50 values of these compounds, which ranged between 2.31 and 3.09 (mg/kg BW). In vivo studies substantiated the potential of the fluoroquinolone derivatives to be developed as synergistic partners for anti-malarial drug combinations.

  17. Identification of Protein Markers in Patients Infected with Plasmodium knowlesi, Plasmodium falciparum and Plasmodium vivax

    Directory of Open Access Journals (Sweden)

    Alan Kang-Wai Mu

    2014-11-01

    Full Text Available Malaria is caused by parasitic protozoans of the genus Plasmodium and is one of the most prevalent infectious diseases in tropical and subtropical regions. For this reason, effective and practical diagnostic methods are urgently needed to control the spread of malaria. The aim of the current study was to identify a panel of new malarial markers, which could be used to diagnose patients infected with various Plasmodium species, including P. knowlesi, P. vivax and P. falciparum. Sera from malaria-infected patients were pooled and compared to control sera obtained from healthy individuals using the isobaric tags for relative and absolute quantitation (iTRAQ technique. Mass spectrometry was used to identify serum proteins and quantify their relative abundance. We found that the levels of several proteins were increased in pooled serum from infected patients, including cell adhesion molecule-4 and C-reactive protein. In contrast, the serum concentration of haptoglobin was reduced in malaria-infected individuals, which we verified by western blot assay. Therefore, these proteins might represent infectious markers of malaria, which could be used to develop novel diagnostic tools for detecting P. knowlesi, P. vivax and P. falciparum. However, these potential malarial markers will need to be validated in a larger population of infected individuals.

  18. Structure-activity-based design of a synthetic malaria peptide eliciting sporozoite inhibitory antibodies in a virosomal formulation.

    NARCIS (Netherlands)

    Okitsu, S.L.; Kienzl, U.; Moehle, K.; Silvie, O.; Peduzzi, E.; Mueller, M.S.; Sauerwein, R.W.; Matile, H.; Zurbriggen, R.; Mazier, D.; Robinson, J.A.; Pluschke, G.

    2007-01-01

    The circumsporozoite protein (CSP) of Plasmodium falciparum is a leading candidate antigen for inclusion in a malaria subunit vaccine. We describe here the design of a conformationally constrained synthetic peptide, designated UK-39, which has structural and antigenic similarity to the NPNA-repeat

  19. Combinatorial gene regulation in Plasmodium falciparum.

    NARCIS (Netherlands)

    Noort, V. van; Huynen, M.A.

    2006-01-01

    The malaria parasite Plasmodium falciparum has a complicated life cycle with large variations in its gene expression pattern, but it contains relatively few specific transcriptional regulators. To elucidate this paradox, we identified regulatory sequences, using an approach that integrates the

  20. Immunoglobulin profile of Nigerian children with Plasmodium ...

    African Journals Online (AJOL)

    SERVER

    2008-01-18

    Jan 18, 2008 ... IgG correlated positively with the level of malarial parasitaemia (r = 0.99). We deduce that ... stages of Plasmodium falciparum and attempts have con- sequently been ... analysis using Microsoft Excel package. RESULTS.

  1. Limitations of microscopy to differentiate Plasmodium species in a region co-endemic for Plasmodium falciparum, Plasmodium vivax and Plasmodium knowlesi

    OpenAIRE

    Barber, Bridget E; William, Timothy; Grigg, Matthew J; Yeo, Tsin W; Anstey, Nicholas M

    2013-01-01

    Abstract Background In areas co-endemic for multiple Plasmodium species, correct diagnosis is crucial for appropriate treatment and surveillance. Species misidentification by microscopy has been reported in areas co-endemic for vivax and falciparum malaria, and may be more frequent in regions where Plasmodium knowlesi also commonly occurs. Methods This prospective study in Sabah, Malaysia, evaluated the accuracy of routine district and referral hospital-based microscopy, and microscopy perfor...

  2. Genome-scale comparison of expanded gene families in Plasmodium ovale wallikeri and Plasmodium ovale curtisi with Plasmodium malariae and with other Plasmodium species.

    Science.gov (United States)

    Ansari, Hifzur Rahman; Templeton, Thomas J; Subudhi, Amit Kumar; Ramaprasad, Abhinay; Tang, Jianxia; Lu, Feng; Naeem, Raeece; Hashish, Yasmeen; Oguike, Mary C; Benavente, Ernest Diez; Clark, Taane G; Sutherland, Colin J; Barnwell, John W; Culleton, Richard; Cao, Jun; Pain, Arnab

    2016-10-01

    Malaria in humans is caused by six species of Plasmodium parasites, of which the nuclear genome sequences for the two Plasmodium ovale spp., P. ovale curtisi and P. ovale wallikeri, and Plasmodium malariae have not yet been analyzed. Here we present an analysis of the nuclear genome sequences of these three parasites, and describe gene family expansions therein. Plasmodium ovale curtisi and P. ovale wallikeri are genetically distinct but morphologically indistinguishable and have sympatric ranges through the tropics of Africa, Asia and Oceania. Both P. ovale spp. show expansion of the surfin variant gene family, and an amplification of the Plasmodium interspersed repeat (pir) superfamily which results in an approximately 30% increase in genome size. For comparison, we have also analyzed the draft nuclear genome of P. malariae, a malaria parasite causing mild malaria symptoms with a quartan life cycle, long-term chronic infections, and wide geographic distribution. Plasmodium malariae shows only a moderate level of expansion of pir genes, and unique expansions of a highly diverged transmembrane protein family with over 550 members and the gamete P25/27 gene family. The observed diversity in the P. ovale wallikeri and P. ovale curtisi surface antigens, combined with their phylogenetic separation, supports consideration that the two parasites be given species status. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Genome-scale comparison of expanded gene families in Plasmodium ovale wallikeri and Plasmodium ovale curtisi with Plasmodium malariae and with other Plasmodium species

    KAUST Repository

    Ansari, Hifzur Rahman; Templeton, Thomas J.; Subudhi, Amit; Ramaprasad, Abhinay; Tang, Jianxia; Lu, Feng; Naeem, Raeece; Hashish, Yasmeen; Oguike, Mary C.; Benavente, Ernest Diez; Clark, Taane G.; Sutherland, Colin J.; Barnwell, John W.; Culleton, Richard; Cao, Jun; Pain, Arnab

    2016-01-01

    Malaria in humans is caused by six species of Plasmodium parasites, of which the nuclear genome sequences for the two Plasmodium ovale spp., P. ovale curtisi and P. ovale wallikeri, and Plasmodium malariae have not yet been analyzed. Here we present an analysis of the nuclear genome sequences of these three parasites, and describe gene family expansions therein. Plasmodium ovale curtisi and P. ovale wallikeri are genetically distinct but morphologically indistinguishable and have sympatric ranges through the tropics of Africa, Asia and Oceania. Both P. ovale spp. show expansion of the surfin variant gene family, and an amplification of the Plasmodium interspersed repeat (pir) superfamily which results in an approximately 30% increase in genome size. For comparison, we have also analyzed the draft nuclear genome of P. malariae, a malaria parasite causing mild malaria symptoms with a quartan life cycle, long-term chronic infections, and wide geographic distribution. Plasmodium malariae shows only a moderate level of expansion of pir genes, and unique expansions of a highly diverged transmembrane protein family with over 550 members and the gamete P25/27 gene family. The observed diversity in the P. ovale wallikeri and P. ovale curtisi surface antigens, combined with their phylogenetic separation, supports consideration that the two parasites be given species status.

  4. Genome-scale comparison of expanded gene families in Plasmodium ovale wallikeri and Plasmodium ovale curtisi with Plasmodium malariae and with other Plasmodium species

    KAUST Repository

    Ansari, Hifzur Rahman

    2016-07-05

    Malaria in humans is caused by six species of Plasmodium parasites, of which the nuclear genome sequences for the two Plasmodium ovale spp., P. ovale curtisi and P. ovale wallikeri, and Plasmodium malariae have not yet been analyzed. Here we present an analysis of the nuclear genome sequences of these three parasites, and describe gene family expansions therein. Plasmodium ovale curtisi and P. ovale wallikeri are genetically distinct but morphologically indistinguishable and have sympatric ranges through the tropics of Africa, Asia and Oceania. Both P. ovale spp. show expansion of the surfin variant gene family, and an amplification of the Plasmodium interspersed repeat (pir) superfamily which results in an approximately 30% increase in genome size. For comparison, we have also analyzed the draft nuclear genome of P. malariae, a malaria parasite causing mild malaria symptoms with a quartan life cycle, long-term chronic infections, and wide geographic distribution. Plasmodium malariae shows only a moderate level of expansion of pir genes, and unique expansions of a highly diverged transmembrane protein family with over 550 members and the gamete P25/27 gene family. The observed diversity in the P. ovale wallikeri and P. ovale curtisi surface antigens, combined with their phylogenetic separation, supports consideration that the two parasites be given species status.

  5. Magnetic nanoparticles are highly toxic to chloroquine-resistant Plasmodium falciparum, dengue virus (DEN-2), and their mosquito vectors.

    Science.gov (United States)

    Murugan, Kadarkarai; Wei, Jiang; Alsalhi, Mohamad Saleh; Nicoletti, Marcello; Paulpandi, Manickam; Samidoss, Christina Mary; Dinesh, Devakumar; Chandramohan, Balamurugan; Paneerselvam, Chellasamy; Subramaniam, Jayapal; Vadivalagan, Chithravel; Wei, Hui; Amuthavalli, Pandiyan; Jaganathan, Anitha; Devanesan, Sandhanasamy; Higuchi, Akon; Kumar, Suresh; Aziz, Al Thabiani; Nataraj, Devaraj; Vaseeharan, Baskaralingam; Canale, Angelo; Benelli, Giovanni

    2017-02-01

    A main challenge in parasitology is the development of reliable tools to prevent or treat mosquito-borne diseases. We investigated the toxicity of magnetic nanoparticles (MNP) produced by Magnetospirillum gryphiswaldense (strain MSR-1) on chloroquine-resistant (CQ-r) and sensitive (CQ-s) Plasmodium falciparum, dengue virus (DEN-2), and two of their main vectors, Anopheles stephensi and Aedes aegypti, respectively. MNP were studied by Fourier-transform infrared spectroscopy and transmission electron microscopy. They were toxic to larvae and pupae of An. stephensi, LC 50 ranged from 2.563 ppm (1st instar larva) to 6.430 ppm (pupa), and Ae. aegypti, LC 50 ranged from 3.231 ppm (1st instar larva) to 7.545 ppm (pupa). MNP IC 50 on P. falciparum were 83.32 μg ml -1 (CQ-s) and 87.47 μg ml -1 (CQ-r). However, the in vivo efficacy of MNP on Plasmodium berghei was low if compared to CQ-based treatments. Moderate cytotoxicity was detected on Vero cells post-treatment with MNP doses lower than 4 μg ml -1 . MNP evaluated at 2-8 μg ml -1 inhibited DEN-2 replication inhibiting the expression of the envelope (E) protein. In conclusion, our findings represent the first report about the use of MNP in medical and veterinary entomology, proposing them as suitable materials to develop reliable tools to combat mosquito-borne diseases.

  6. Plasmodium vivax Transmission in Africa.

    Directory of Open Access Journals (Sweden)

    Rosalind E Howes

    2015-11-01

    Full Text Available Malaria in sub-Saharan Africa has historically been almost exclusively attributed to Plasmodium falciparum (Pf. Current diagnostic and surveillance systems in much of sub-Saharan Africa are not designed to identify or report non-Pf human malaria infections accurately, resulting in a dearth of routine epidemiological data about their significance. The high prevalence of Duffy negativity provided a rationale for excluding the possibility of Plasmodium vivax (Pv transmission. However, review of varied evidence sources including traveller infections, community prevalence surveys, local clinical case reports, entomological and serological studies contradicts this viewpoint. Here, these data reports are weighted in a unified framework to reflect the strength of evidence of indigenous Pv transmission in terms of diagnostic specificity, size of individual reports and corroboration between evidence sources. Direct evidence was reported from 21 of the 47 malaria-endemic countries studied, while 42 countries were attributed with infections of visiting travellers. Overall, moderate to conclusive evidence of transmission was available from 18 countries, distributed across all parts of the continent. Approximately 86.6 million Duffy positive hosts were at risk of infection in Africa in 2015. Analysis of the mechanisms sustaining Pv transmission across this continent of low frequency of susceptible hosts found that reports of Pv prevalence were consistent with transmission being potentially limited to Duffy positive populations. Finally, reports of apparent Duffy-independent transmission are discussed. While Pv is evidently not a major malaria parasite across most of sub-Saharan Africa, the evidence presented here highlights its widespread low-level endemicity. An increased awareness of Pv as a potential malaria parasite, coupled with policy shifts towards species-specific diagnostics and reporting, will allow a robust assessment of the public health

  7. Clinical and parasitological profiles of patients with non-complicated Plasmodium falciparum and Plasmodium vivax malaria in northwestern Colombia

    OpenAIRE

    Knudson-Ospina, Angélica; Sánchez-Pedraza, Ricardo; Pérez-Mazorra, Manuel Alberto; Cortés-Cortés, Liliana Jazmín; Guerra-Vega, Ángela Patricia; Nicholls-Orejuela, Rubén Santiago

    2015-01-01

    Antecedentes. En Colombia existen pocos estudios que buscan encontrar diferencias clínicas y parasitológicas en la malaria causada por Plasmodium falciparum y Plasmodium vivax. Objetivo. Describir el perfil clínico y parasitológico de las malarias por Plasmodium falciparum y Plasmodium vivax no complicadas en Tierralta, Córdoba, Colombia. Materiales y métodos. Se evaluaron pacientes con paludismo no complicado por Plasmodium falciparum y Plasmodium vivax según los protocolos estandarizados po...

  8. A Large Size Chimeric Highly Immunogenic Peptide Presents Multistage Plasmodium Antigens as a Vaccine Candidate System against Malaria.

    Science.gov (United States)

    Lozano, José Manuel; Varela, Yahson; Silva, Yolanda; Ardila, Karen; Forero, Martha; Guasca, Laura; Guerrero, Yuly; Bermudez, Adriana; Alba, Patricia; Vanegas, Magnolia; Patarroyo, Manuel Elkin

    2017-11-01

    Rational strategies for obtaining malaria vaccine candidates should include not only a proper selection of target antigens for antibody stimulation, but also a versatile molecular design based on ordering the right pieces from the complex pathogen molecular puzzle towards more active and functional immunogens. Classical Plasmodium falciparum antigens regarded as vaccine candidates have been selected as model targets in this study. Among all possibilities we have chosen epitopes of Pf CSP, STARP; MSA1 and Pf 155/RESA from pre- and erythrocyte stages respectively for designing a large 82-residue chimeric immunogen. A number of options aimed at diminishing steric hindrance for synthetic procedures were assessed based on standard Fmoc chemistry such as building block orthogonal ligation; pseudo-proline and microwave-assisted procedures, therefore the large-chimeric target was produced, characterized and immunologically tested. Antigenicity and functional in vivo efficacy tests of the large-chimera formulations administered alone or as antigen mixtures have proven the stimulation of high antibody titers, showing strong correlation with protection and parasite clearance of vaccinated BALB/c mice after being lethally challenged with both P. berghei -ANKA and P. yoelii 17XL malaria strains. Besides, 3D structure features shown by the large-chimera encouraged as to propose using these rational designed large synthetic molecules as reliable vaccine candidate-presenting systems.

  9. A Large Size Chimeric Highly Immunogenic Peptide Presents Multistage Plasmodium Antigens as a Vaccine Candidate System against Malaria

    Directory of Open Access Journals (Sweden)

    José Manuel Lozano

    2017-11-01

    Full Text Available Rational strategies for obtaining malaria vaccine candidates should include not only a proper selection of target antigens for antibody stimulation, but also a versatile molecular design based on ordering the right pieces from the complex pathogen molecular puzzle towards more active and functional immunogens. Classical Plasmodium falciparum antigens regarded as vaccine candidates have been selected as model targets in this study. Among all possibilities we have chosen epitopes of PfCSP, STARP; MSA1 and Pf155/RESA from pre- and erythrocyte stages respectively for designing a large 82-residue chimeric immunogen. A number of options aimed at diminishing steric hindrance for synthetic procedures were assessed based on standard Fmoc chemistry such as building block orthogonal ligation; pseudo-proline and microwave-assisted procedures, therefore the large-chimeric target was produced, characterized and immunologically tested. Antigenicity and functional in vivo efficacy tests of the large-chimera formulations administered alone or as antigen mixtures have proven the stimulation of high antibody titers, showing strong correlation with protection and parasite clearance of vaccinated BALB/c mice after being lethally challenged with both P. berghei-ANKA and P. yoelii 17XL malaria strains. Besides, 3D structure features shown by the large-chimera encouraged as to propose using these rational designed large synthetic molecules as reliable vaccine candidate-presenting systems.

  10. The activities of current antimalarial drugs on the life cycle stages of Plasmodium: a comparative study with human and rodent parasites.

    Science.gov (United States)

    Delves, Michael; Plouffe, David; Scheurer, Christian; Meister, Stephan; Wittlin, Sergio; Winzeler, Elizabeth A; Sinden, Robert E; Leroy, Didier

    2012-02-01

    Malaria remains a disease of devastating global impact, killing more than 800,000 people every year-the vast majority being children under the age of 5. While effective therapies are available, if malaria is to be eradicated a broader range of small molecule therapeutics that are able to target the liver and the transmissible sexual stages are required. These new medicines are needed both to meet the challenge of malaria eradication and to circumvent resistance. Little is known about the wider stage-specific activities of current antimalarials that were primarily designed to alleviate symptoms of malaria in the blood stage. To overcome this critical gap, we developed assays to measure activity of antimalarials against all life stages of malaria parasites, using a diverse set of human and nonhuman parasite species, including male gamete production (exflagellation) in Plasmodium falciparum, ookinete development in P. berghei, oocyst development in P. berghei and P. falciparum, and the liver stage of P. yoelii. We then compared 50 current and experimental antimalarials in these assays. We show that endoperoxides such as OZ439, a stable synthetic molecule currently in clinical phase IIa trials, are strong inhibitors of gametocyte maturation/gamete formation and impact sporogony; lumefantrine impairs development in the vector; and NPC-1161B, a new 8-aminoquinoline, inhibits sporogony. These data enable objective comparisons of the strengths and weaknesses of each chemical class at targeting each stage of the lifecycle. Noting that the activities of many compounds lie within achievable blood concentrations, these results offer an invaluable guide to decisions regarding which drugs to combine in the next-generation of antimalarial drugs. This study might reveal the potential of life-cycle-wide analyses of drugs for other pathogens with complex life cycles.

  11. The Activities of Current Antimalarial Drugs on the Life Cycle Stages of Plasmodium: A Comparative Study with Human and Rodent Parasites

    Science.gov (United States)

    Delves, Michael; Plouffe, David; Scheurer, Christian; Meister, Stephan; Wittlin, Sergio; Winzeler, Elizabeth A.; Sinden, Robert E.; Leroy, Didier

    2012-01-01

    Background Malaria remains a disease of devastating global impact, killing more than 800,000 people every year—the vast majority being children under the age of 5. While effective therapies are available, if malaria is to be eradicated a broader range of small molecule therapeutics that are able to target the liver and the transmissible sexual stages are required. These new medicines are needed both to meet the challenge of malaria eradication and to circumvent resistance. Methods and Findings Little is known about the wider stage-specific activities of current antimalarials that were primarily designed to alleviate symptoms of malaria in the blood stage. To overcome this critical gap, we developed assays to measure activity of antimalarials against all life stages of malaria parasites, using a diverse set of human and nonhuman parasite species, including male gamete production (exflagellation) in Plasmodium falciparum, ookinete development in P. berghei, oocyst development in P. berghei and P. falciparum, and the liver stage of P. yoelii. We then compared 50 current and experimental antimalarials in these assays. We show that endoperoxides such as OZ439, a stable synthetic molecule currently in clinical phase IIa trials, are strong inhibitors of gametocyte maturation/gamete formation and impact sporogony; lumefantrine impairs development in the vector; and NPC-1161B, a new 8-aminoquinoline, inhibits sporogony. Conclusions These data enable objective comparisons of the strengths and weaknesses of each chemical class at targeting each stage of the lifecycle. Noting that the activities of many compounds lie within achievable blood concentrations, these results offer an invaluable guide to decisions regarding which drugs to combine in the next-generation of antimalarial drugs. This study might reveal the potential of life-cycle–wide analyses of drugs for other pathogens with complex life cycles. Please see later in the article for the Editors' Summary PMID

  12. Plasmodium falciparum incidence relative to entomologic inoculation rates at a site proposed for testing malaria vaccines in western Kenya.

    Science.gov (United States)

    Beier, J C; Oster, C N; Onyango, F K; Bales, J D; Sherwood, J A; Perkins, P V; Chumo, D K; Koech, D V; Whitmire, R E; Roberts, C R

    1994-05-01

    Relationships between Plasmodium falciparum incidence and entomologic inoculation rates (EIRs) were determined for a 21-month period in Saradidi, western Kenya, in preparation for malaria vaccine field trials. Children, ranging in age from six months to six years and treated to clear malaria parasites, were monitored daily for up to 12 weeks to detect new malaria infections. Overall, new P. falciparum infections were detected in 77% of 809 children. The percentage of children that developed infections per two-week period averaged 34.7%, ranging from 7.3% to 90.9%. Transmission by vector populations was detected in 86.4% (38 of 44) of the two-week periods, with daily EIRs averaging 0.75 infective bites per person. Periods of intense transmission during April to August, and from November to January, coincided with seasonal rains. Relationships between daily malaria attack rates and EIRs indicated that an average of only 7.5% (1 in 13) of the sporozoite inoculations produced new infections in children. Regression analysis demonstrated that EIRs accounted for 74% of the variation in attack rates. One of the components of the EIR, the human-biting rate, alone accounted for 68% of the variation in attack rates. Thus, measurements of either the EIR or the human-biting rate can be used to predict corresponding attack rates in children. These baseline epidemiologic studies indicate that the intense transmission patterns of P. falciparum in Saradidi will provide excellent conditions for evaluating malaria vaccine efficacy.

  13. Singapore's Anopheles sinensis Form A is susceptible to Plasmodium vivax isolates from the western Thailand-Myanmar border.

    Science.gov (United States)

    Pang, Sook-Cheng; Andolina, Chiara; Malleret, Benoit; Christensen, Peter R; Lam-Phua, Sai-Gek; Razak, Muhammad Aliff Bin Abdul; Chong, Chee-Seng; Li, Daiqin; Chu, Cindy S; Russell, Bruce; Rénia, Laurent; Ng, Lee-Ching; Nosten, Francois

    2017-11-16

    Singapore has been certified malaria-free by the World Health Organization since November 1982. However, sporadic autochthonous malaria outbreaks do occur. In one of the most recent outbreaks of vivax malaria, an entomological investigation identified Anopheles sinensis as the most probable vector. As metaphase karyotype studies divided An. sinensis into two forms, A and B, with different vector competence: the investigation of vector competence of An. sinensis found in Singapore was thus pursued using Plasmodium vivax field isolates from the Thailand-Myanmar border. Adults and larvae An. sinensis were collected from Singapore from 14 different locations, using various trapping and collection methods between September 2013 and January 2016. Molecular identification of An. sinensis species were conducted by amplifying the ITS2 and CO1 region using PCR. Experimental infections of An. sinensis using blood from seven patients infected with P. vivax from the Thailand-Myanmar border were conducted with Anopheles cracens (An. dirus B) as control. Phylogenetic analysis showed that An. sinensis (F 22 , F 2 and collected from outbreak areas) found in Singapore was entirely Form A, and closely related to An. sinensis Form A from Thailand. Artificial infection of these Singapore strain An. sinensis Form A resulted in the development of oocysts in four experiments, with the number of sporozoites produced by one An. sinensis ranging from 4301 to 14,538. Infection experiments showed that An. sinensis Form A from Singapore was susceptible to Thai-Myanmar P. vivax strain, suggesting a potential role as a malaria vector in Singapore.

  14. Plasmodium falciparum CS protein - prime malaria vaccine candidate: definition of the human CTL domain and analysis of its variation

    Directory of Open Access Journals (Sweden)

    Denise L. Doolan

    1992-01-01

    Full Text Available Studies in mice have shown that immunity to malaria sporozoites is mediated primarily by citotoxic T lymphocytes (CTL specific for epitopes within the circumsporozoite (CS protein. Humans, had never been shown to generate CTL against any malaria or other parasite protein. The design of a sub-unit vaccine for humans ralies on the epitopes recognized by CTL being identified and polymorphisms therein being defined. We have developed a novel technique using an entire series of overlapping synthetic peptides to define the epitopes of the Plasmodium falciparum CS protein recognized by human CTL and have analyzed the sequence variation of the protein with respect to the identified CTL epitopic domain. We have demonstrated that some humans can indeed generate CTL. against the P. falciparum CS protein. Furthermore, the extent of variation observed for the CTL recognition domain is finite and the combination of peptides necessary for inclusion in a polyvalent vaccine may be small. If ways can be found to increase immune responsiveness, then a vaccine designed to stimulate CS protein-specific CTL activity may prevent malaria.

  15. Seasonal and Spatial Dynamics of the Primary Vector of Plasmodium knowlesi within a Major Transmission Focus in Sabah, Malaysia.

    Directory of Open Access Journals (Sweden)

    Meng L Wong

    Full Text Available The simian malaria parasite Plasmodium knowlesi is emerging as a public health problem in Southeast Asia, particularly in Malaysian Borneo where it now accounts for the greatest burden of malaria cases and deaths. Control is hindered by limited understanding of the ecology of potential vector species.We conducted a one year longitudinal study of P. knowlesi vectors in three sites within an endemic area of Sabah, Malaysia. All mosquitoes were captured using human landing catch. Anopheles mosquitoes were dissected to determine, oocyst, sporozoites and parous rate. Anopheles balabacensis is confirmed as the primary vector of. P. knowlesi (using nested PCR in Sabah for the first time. Vector densities were significantly higher and more seasonally variable in the village than forest or small scale farming site. However An. balabacensis survival and P. knowlesi infection rates were highest in forest and small scale farm sites. Anopheles balabacensis mostly bites humans outdoors in the early evening between 1800 to 2000 hrs.This study indicates transmission is unlikely to be prevented by bednets. This combined with its high vectorial capacity poses a threat to malaria elimination programmes within the region.

  16. Effect of clinically approved HDAC inhibitors on Plasmodium, Leishmania and Schistosoma parasite growth.

    Science.gov (United States)

    Chua, Ming Jang; Arnold, Megan S J; Xu, Weijun; Lancelot, Julien; Lamotte, Suzanne; Späth, Gerald F; Prina, Eric; Pierce, Raymond J; Fairlie, David P; Skinner-Adams, Tina S; Andrews, Katherine T

    2017-04-01

    Malaria, schistosomiasis and leishmaniases are among the most prevalent tropical parasitic diseases and each requires new innovative treatments. Targeting essential parasite pathways, such as those that regulate gene expression and cell cycle progression, is a key strategy for discovering new drug leads. In this study, four clinically approved anti-cancer drugs (Vorinostat, Belinostat, Panobinostat and Romidepsin) that target histone/lysine deacetylase enzymes were examined for in vitro activity against Plasmodium knowlesi, Schistosoma mansoni, Leishmania amazonensis and L. donovani parasites and two for in vivo activity in a mouse malaria model. All four compounds were potent inhibitors of P. knowlesi malaria parasites (IC 50 9-370 nM), with belinostat, panobinostat and vorinostat having 8-45 fold selectivity for the parasite over human neonatal foreskin fibroblast (NFF) or human embryonic kidney (HEK 293) cells, while romidepsin was not selective. Each of the HDAC inhibitor drugs caused hyperacetylation of P. knowlesi histone H4. None of the drugs was active against Leishmania amastigote or promastigote parasites (IC 50  > 20 μM) or S. mansoni schistosomula (IC 50  > 10 μM), however romidepsin inhibited S. mansoni adult worm parings and egg production (IC 50 ∼10 μM). Modest in vivo activity was observed in P. berghei infected mice dosed orally with vorinostat or panobinostat (25 mg/kg twice daily for four days), with a significant reduction in parasitemia observed on days 4-7 and 4-10 after infection (P < 0.05), respectively. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Effect of clinically approved HDAC inhibitors on Plasmodium, Leishmania and Schistosoma parasite growth

    Directory of Open Access Journals (Sweden)

    Ming Jang Chua

    2017-04-01

    Full Text Available Malaria, schistosomiasis and leishmaniases are among the most prevalent tropical parasitic diseases and each requires new innovative treatments. Targeting essential parasite pathways, such as those that regulate gene expression and cell cycle progression, is a key strategy for discovering new drug leads. In this study, four clinically approved anti-cancer drugs (Vorinostat, Belinostat, Panobinostat and Romidepsin that target histone/lysine deacetylase enzymes were examined for in vitro activity against Plasmodium knowlesi, Schistosoma mansoni, Leishmania amazonensis and L. donovani parasites and two for in vivo activity in a mouse malaria model. All four compounds were potent inhibitors of P. knowlesi malaria parasites (IC50 9–370 nM, with belinostat, panobinostat and vorinostat having 8–45 fold selectivity for the parasite over human neonatal foreskin fibroblast (NFF or human embryonic kidney (HEK 293 cells, while romidepsin was not selective. Each of the HDAC inhibitor drugs caused hyperacetylation of P. knowlesi histone H4. None of the drugs was active against Leishmania amastigote or promastigote parasites (IC50 > 20 μM or S. mansoni schistosomula (IC50 > 10 μM, however romidepsin inhibited S. mansoni adult worm parings and egg production (IC50 ∼10 μM. Modest in vivo activity was observed in P. berghei infected mice dosed orally with vorinostat or panobinostat (25 mg/kg twice daily for four days, with a significant reduction in parasitemia observed on days 4–7 and 4–10 after infection (P < 0.05, respectively.

  18. Efficacy, Pharmacokinetics, and Metabolism of Tetrahydroquinoline Inhibitors of Plasmodium falciparum Protein Farnesyltransferase▿ †

    Science.gov (United States)

    Van Voorhis, Wesley C.; Rivas, Kasey L.; Bendale, Pravin; Nallan, Laxman; Hornéy, Carolyn; Barrett, Lynn K.; Bauer, Kevin D.; Smart, Brian P.; Ankala, Sudha; Hucke, Oliver; Verlinde, Christophe L. M. J.; Chakrabarti, Debopam; Strickland, Corey; Yokoyama, Kohei; Buckner, Frederick S.; Hamilton, Andrew D.; Williams, David K.; Lombardo, Louis J.; Floyd, David; Gelb, Michael H.

    2007-01-01

    New antimalarials are urgently needed. We have shown that tetrahydroquinoline (THQ) protein farnesyltransferase (PFT) inhibitors (PFTIs) are effective against the Plasmodium falciparum PFT and are effective at killing P. falciparum in vitro. Previously described THQ PFTIs had limitations of poor oral bioavailability and rapid clearance from the circulation of rodents. In this paper, we validate both the Caco-2 cell permeability model for predicting THQ intestinal absorption and the in vitro liver microsome model for predicting THQ clearance in vivo. Incremental improvements in efficacy, oral absorption, and clearance rate were monitored by in vitro tests; and these tests were followed up with in vivo absorption, distribution, metabolism, and excretion studies. One compound, PB-93, achieved cure when it was given orally to P. berghei-infected rats every 8 h for a total of 72 h. However, PB-93 was rapidly cleared, and dosing every 12 h failed to cure the rats. Thus, the in vivo results corroborate the in vitro pharmacodynamics and demonstrate that 72 h of continuous high-level exposure to PFTIs is necessary to kill plasmodia. The metabolism of PB-93 was demonstrated by a novel technique that relied on double labeling with a radiolabel and heavy isotopes combined with radiometric liquid chromatography and mass spectrometry. The major liver microsome metabolite of PB-93 has the PFT Zn-binding N-methyl-imidazole removed; this metabolite is inactive in blocking PFT function. By solving the X-ray crystal structure of PB-93 bound to rat PFT, a model of PB-93 bound to malarial PFT was constructed. This model suggests areas of the THQ PFTIs that can be modified to retain efficacy and protect the Zn-binding N-methyl-imidazole from dealkylation. PMID:17606674

  19. Haemoglobin C and S role in acquired immunity against Plasmodium falciparum malaria.

    Directory of Open Access Journals (Sweden)

    Federica Verra

    2007-10-01

    Full Text Available A recently proposed mechanism of protection for haemoglobin C (HbC; beta6Glu-->Lys links an abnormal display of PfEMP1, an antigen involved in malaria pathogenesis, on the surface of HbC infected erythrocytes together with the observation of reduced cytoadhesion of parasitized erythrocytes and impaired rosetting in vitro. We investigated the impact of this hypothesis on the development of acquired immunity against Plasmodium falciparum variant surface antigens (VSA encoding PfEMP1 in HbC in comparison with HbA and HbS carriers of Burkina Faso. We measured: i total IgG against a single VSA, A4U, and against a panel of VSA from severe malaria cases in human sera from urban and rural areas of Burkina Faso of different haemoglobin genotypes (CC, AC, AS, SC, SS; ii total IgG against recombinant proteins of P. falciparum asexual sporozoite, blood stage antigens, and parasite schizont extract; iii total IgG against tetanus toxoid. Results showed that the reported abnormal cell-surface display of PfEMP1 on HbC infected erythrocytes observed in vitro is not associated to lower anti- PfEMP1 response in vivo. Higher immune response against the VSA panel and malaria antigens were observed in all adaptive genotypes containing at least one allelic variant HbC or HbS in the low transmission urban area whereas no differences were detected in the high transmission rural area. In both contexts the response against tetanus toxoid was not influenced by the beta-globin genotype. These findings suggest that both HbC and HbS affect the early development of naturally acquired immunity against malaria. The enhanced immune reactivity in both HbC and HbS carriers supports the hypothesis that the protection against malaria of these adaptive genotypes might be at least partially mediated by acquired immunity against malaria.

  20. Towards an in vitro model of Plasmodium hypnozoites suitable for drug discovery.

    Science.gov (United States)

    Dembele, Laurent; Gego, Audrey; Zeeman, Anne-Marie; Franetich, Jean-François; Silvie, Olivier; Rametti, Armelle; Le Grand, Roger; Dereuddre-Bosquet, Nathalie; Sauerwein, Robert; van Gemert, Geert-Jan; Vaillant, Jean-Christophe; Thomas, Alan W; Snounou, Georges; Kocken, Clemens H M; Mazier, Dominique

    2011-03-31

    Amongst the Plasmodium species in humans, only P. vivax and P. ovale produce latent hepatic stages called hypnozoites, which are responsible for malaria episodes long after a mosquito bite. Relapses contribute to increased morbidity, and complicate malaria elimination programs. A single drug effective against hypnozoites, primaquine, is available, but its deployment is curtailed by its haemolytic potential in glucose-6-phosphate dehydrogenase deficient persons. Novel compounds are thus urgently needed to replace primaquine. Discovery of compounds active against hypnozoites is restricted to the in vivo P. cynomolgi-rhesus monkey model. Slow growing hepatic parasites reminiscent of hypnozoites had been noted in cultured P. vivax-infected hepatoma cells, but similar forms are also observed in vitro by other species including P. falciparum that do not produce hypnozoites. P. falciparum or P. cynomolgi sporozoites were used to infect human or Macaca fascicularis primary hepatocytes, respectively. The susceptibility of the slow and normally growing hepatic forms obtained in vitro to three antimalarial drugs, one active against hepatic forms including hypnozoites and two only against the growing forms, was measured. The non-dividing slow growing P. cynomolgi hepatic forms, observed in vitro in primary hepatocytes from the natural host Macaca fascicularis, can be distinguished from similar forms seen in P. falciparum-infected human primary hepatocytes by the differential action of selected anti-malarial drugs. Whereas atovaquone and pyrimethamine are active on all the dividing hepatic forms observed, the P. cynomolgi slow growing forms are highly resistant to treatment by these drugs, but remain susceptible to primaquine. Resistance of the non-dividing P. cynomolgi forms to atovaquone and pyrimethamine, which do not prevent relapses, strongly suggests that these slow growing forms are hypnozoites. This represents a first step towards the development of a practical medium

  1. Towards an in vitro model of Plasmodium hypnozoites suitable for drug discovery.

    Directory of Open Access Journals (Sweden)

    Laurent Dembele

    2011-03-01

    Full Text Available Amongst the Plasmodium species in humans, only P. vivax and P. ovale produce latent hepatic stages called hypnozoites, which are responsible for malaria episodes long after a mosquito bite. Relapses contribute to increased morbidity, and complicate malaria elimination programs. A single drug effective against hypnozoites, primaquine, is available, but its deployment is curtailed by its haemolytic potential in glucose-6-phosphate dehydrogenase deficient persons. Novel compounds are thus urgently needed to replace primaquine. Discovery of compounds active against hypnozoites is restricted to the in vivo P. cynomolgi-rhesus monkey model. Slow growing hepatic parasites reminiscent of hypnozoites had been noted in cultured P. vivax-infected hepatoma cells, but similar forms are also observed in vitro by other species including P. falciparum that do not produce hypnozoites.P. falciparum or P. cynomolgi sporozoites were used to infect human or Macaca fascicularis primary hepatocytes, respectively. The susceptibility of the slow and normally growing hepatic forms obtained in vitro to three antimalarial drugs, one active against hepatic forms including hypnozoites and two only against the growing forms, was measured.The non-dividing slow growing P. cynomolgi hepatic forms, observed in vitro in primary hepatocytes from the natural host Macaca fascicularis, can be distinguished from similar forms seen in P. falciparum-infected human primary hepatocytes by the differential action of selected anti-malarial drugs. Whereas atovaquone and pyrimethamine are active on all the dividing hepatic forms observed, the P. cynomolgi slow growing forms are highly resistant to treatment by these drugs, but remain susceptible to primaquine.Resistance of the non-dividing P. cynomolgi forms to atovaquone and pyrimethamine, which do not prevent relapses, strongly suggests that these slow growing forms are hypnozoites. This represents a first step towards the development of a

  2. Efficacy of Artemether in Unresolving Plasmodium Falciparum Malaria

    African Journals Online (AJOL)

    The emergence of possible resistant Plasmodium falciparum malaria to artemisinin known for its immense benefit in malaria chemotherapy is worrisome. We report a case of unresolving Plasmodium falciparum malaria to Artesunate treatment in a 29- year old man in Enugu Nigeria. Plasmodium falciparum count of Giemsa ...

  3. Dicty_cDB: SLJ419 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available |CB367289.1 E38 early-oocyst library Plasmodium berghei/Anopheles stephensi mixe...7 |CB367287.1 E830 early-oocyst library Plasmodium berghei/Anopheles stephensi mixed EST library cDNA clone ...oocyst library Plasmodium berghei/Anopheles stephensi mixed EST library cDNA clon...ly-oocyst library Plasmodium berghei/Anopheles stephensi mixed EST library cDNA clone E3015 similar to Plasm

  4. Helminth parasites alter protection against Plasmodium infection.

    Science.gov (United States)

    Salazar-Castañon, Víctor H; Legorreta-Herrera, Martha; Rodriguez-Sosa, Miriam

    2014-01-01

    More than one-third of the world's population is infected with one or more helminthic parasites. Helminth infections are prevalent throughout tropical and subtropical regions where malaria pathogens are transmitted. Malaria is the most widespread and deadliest parasitic disease. The severity of the disease is strongly related to parasite density and the host's immune responses. Furthermore, coinfections between both parasites occur frequently. However, little is known regarding how concomitant infection with helminths and Plasmodium affects the host's immune response. Helminthic infections are frequently massive, chronic, and strong inductors of a Th2-type response. This implies that infection by such parasites could alter the host's susceptibility to subsequent infections by Plasmodium. There are a number of reports on the interactions between helminths and Plasmodium; in some, the burden of Plasmodium parasites increased, but others reported a reduction in the parasite. This review focuses on explaining many of these discrepancies regarding helminth-Plasmodium coinfections in terms of the effects that helminths have on the immune system. In particular, it focuses on helminth-induced immunosuppression and the effects of cytokines controlling polarization toward the Th1 or Th2 arms of the immune response.

  5. Plasmodium falciparum: attenuation by irradiation

    International Nuclear Information System (INIS)

    Waki, S.; Yonome, I.; Suzuki, M.

    1983-01-01

    The effect of irradiation on the in vitro growth of Plasmodium falciparum was investigated. The cultured malarial parasites at selected stages of development were exposed to gamma rays and the sensitivity of each stage was determined. The stages most sensitive to irradiation were the ring forms and the early trophozoites; late trophozoites were relatively insensitive. The greatest resistance was shown when parasites were irradiated at a time of transition from the late trophozoite and schizont stages to young ring forms. The characteristics of radiosensitive variation in the parasite cycle resembled that of mammalian cells. Growth curves of parasites exposed to doses of irradiation upto 150 gray had the same slope as nonirradiated controls but parasites which were exposed to 200 gray exhibited a growth curve which was less steep than that for parasites in other groups. Less than 10 organisms survived from the 10(6) parasites exposed to this high dose of irradiation; the possibility exists of obtaining radiation-attenuated P. falciparum

  6. Occurrence of Plasmodium in Anatidae

    Science.gov (United States)

    Herman, C.M.; Kocan, R.M.

    1970-01-01

    Until a little over a decade ago reports of Plasrnodium in geese, ducks, and swans were the result of examination of single blood smears from wild birds. One would gather from the earlier studies that Anatidae are infrequently infected. During the past decade we have conducted studies on prevalence of Plasmodium by an isodiagnosis technique, inoculating blood from wild birds into captive young geese, ducks, and other species of birds and determining the status of infection in the donors by examination of repetitive blood smears from the recipients. Examination by this technique of a series of adult Canada geese from the Seney National Wildlife Refuge in northern Michigan uncovered a prevalence of 60% during five successive years. Domestic geese were the primary recipients but we found that several other species of geese, ducks, and gulls were also susceptible. Similar studies on Canada geese from other areas (Maryland, New Jersey, New York, and southern Michigan) uncovered infection rates from zero to 27%. Following isolation of Plasmodlum in a single canvasback duck (Aythya valisineria) in southern Michigan by inoculation into a domestic duck, a series of 88 canvasbacks from Chesapeake Bay in Maryland this winter uncovered an infection rate of 27%. The most common parasite observed in both the geese and was as P. circumflexum.

  7. Response of tumour necrosis factor alpha (TNF ) in blood and spleen mice that vaccinated with P.berghei radiation

    International Nuclear Information System (INIS)

    Darlina; Tur R; Teja K

    2015-01-01

    Tumor necrosis factor is a glycoprotein derived from helper T lymphocytes that play an important role in the body's response against malaria infection. However, TNF-α has double play that is on appropriate levels will provide protection and healing, while at excessive levels which may be a response to hyperparasitemia. Thus investigated the expression of TNF alpha secreted blood lymphocytes and spleen cells the mice that's infected with 1 x 10 7 P.berghei infectious or inactivated by radiation. Levels of TNF alpha serum and spleen cell culture medium was monitored on days 2, 7, 14 post infection. Monitoring of parasite growth every two days for 60 days. Determination of TNF alpha levels were measure using ELISA. The results showed parasitaemia mice infected with 175 Gy irradiated parasites have pre patent period of 16 days longer than the control (non-irradiated parasites) with low parasitaemia. TNF alpha concentration that secreted spleen cells of mice vaccinated higher than control mice. Concentration of TNF alpha that secreted blood lymphocyte of mice vaccinated lower than control mice. It was concluded that the secretion of TNF alpha by blood lymphocytes caused more pathogenic factors of the parasite, while the secretion of TNF alpha in spleen due to an immune response against the parasite. (author)

  8. Filarial worms reduce Plasmodium infectivity in mosquitoes.

    Directory of Open Access Journals (Sweden)

    Matthew T Aliota

    2011-02-01

    Full Text Available Co-occurrence of malaria and filarial worm parasites has been reported, but little is known about the interaction between filarial worm and malaria parasites with the same Anopheles vector. Herein, we present data evaluating the interaction between Wuchereria bancrofti and Anopheles punctulatus in Papua New Guinea (PNG. Our field studies in PNG demonstrated that An. punctulatus utilizes the melanization immune response as a natural mechanism of filarial worm resistance against invading W. bancrofti microfilariae. We then conducted laboratory studies utilizing the mosquitoes Armigeres subalbatus and Aedes aegypti and the parasites Brugia malayi, Brugia pahangi, Dirofilaria immitis, and Plasmodium gallinaceum to evaluate the hypothesis that immune activation and/or development by filarial worms negatively impact Plasmodium development in co-infected mosquitoes. Ar. subalbatus used in this study are natural vectors of P. gallinaceum and B. pahangi and they are naturally refractory to B. malayi (melanization-based refractoriness.Mosquitoes were dissected and Plasmodium development was analyzed six days after blood feeding on either P. gallinaceum alone or after taking a bloodmeal containing both P. gallinaceum and B. malayi or a bloodmeal containing both P. gallinaceum and B. pahangi. There was a significant reduction in the prevalence and mean intensity of Plasmodium infections in two species of mosquito that had dual infections as compared to those mosquitoes that were infected with Plasmodium alone, and was independent of whether the mosquito had a melanization immune response to the filarial worm or not. However, there was no reduction in Plasmodium development when filarial worms were present in the bloodmeal (D. immitis but midgut penetration was absent, suggesting that factors associated with penetration of the midgut by filarial worms likely are responsible for the observed reduction in malaria parasite infections.These results could have an

  9. Piperaquine Resistance in Plasmodium falciparum, West Africa.

    Science.gov (United States)

    Inoue, Juliana; Silva, Miguel; Fofana, Bakary; Sanogo, Kassim; Mårtensson, Andreas; Sagara, Issaka; Björkman, Anders; Veiga, Maria Isabel; Ferreira, Pedro Eduardo; Djimde, Abdoulaye; Gil, José Pedro

    2018-08-17

    Dihydroartemisinin/piperaquine (DHA/PPQ) is increasingly deployed as antimalaria drug in Africa. We report the detection in Mali of Plasmodium falciparum infections carrying plasmepsin 2 duplications (associated with piperaquine resistance) in 7/65 recurrent infections within 2 months after DHA/PPQ treatment. These findings raise concerns about the long-term efficacy of DHA/PPQ treatment in Africa.

  10. Plasmodium falciparum malaria and antimalarial interventions in ...

    African Journals Online (AJOL)

    Plasmodium falciparum malaria is one of the most important parasitic diseases affecting sub-Saharan Africa, despite the availability of interventions. It exerts tremendous socio-economic and medical burden on the continent, particularly in under five children and pregnant women. In this review, we have attempted to ...

  11. SHORT COMMUNICATION High prevalence of Plasmodium ...

    African Journals Online (AJOL)

    Dell

    Volume 20, Number 1, January 2018. 1. SHORT COMMUNICATION ... This study was designed to establish the prevalence of Plasmodium falciparum malaria among HIV infected populations. ... The prevalence of P. falciparum was high among HIV seropositive individuals in the Lake Victoria Zone, which calls for additional ...

  12. Plasmodium knowlesi in travellers, update 2014.

    Science.gov (United States)

    Müller, Mattia; Schlagenhauf, Patricia

    2014-05-01

    Since the initial discovery of Plasmodium knowlesi in Malaysia, cases have been reported from several neighbouring countries. Tourism has also resulted in an increasing number of cases diagnosed in Europe, America, and Oceania. In this review we focus on the risk of the travel-associated acquisition of P. knowlesi malaria. A search of the literature in PubMed was carried out to identify articles and literature on the distribution of P. knowlesi infections in Southeast Asia and details of its acquisition and importation by travellers to other continents. The cut-off date for the search was December 1, 2013. Search words used were: "Plasmodium knowlesi", "Plasmodium knowlesi infections", "Plasmodium knowlesi travellers", "Plasmodium knowlesi prevalence", "Plasmodium knowlesi host", "Plasmodium knowlesi vector" "Plasmodium knowlesi RDT", and "Plasmodium knowlesi Malaysia". Traveller numbers to Malaysia were obtained from the Tourism Malaysia website. A total of 103 articles were found. Using a selection of these and others identified from the reference lists of the papers, we based our review on a total of 66 articles. P. knowlesi malaria appears to be the most common malaria species in Malaysian Borneo and is also widely distributed on the Malaysian mainland. Furthermore, locally transmitted cases of P. knowlesi malaria have been reported in Thailand, the Philippines, Vietnam, Singapore, Myanmar, Indonesian Borneo, and Cambodia. Two cases have been reported from non-endemic countries in Asia (Japan and Taiwan) in people with a history of travel to Malaysia and the Philippines. Twelve cases were imported to their home countries by travellers from other continents: two from the USA, two from the Netherlands, two from Germany, and one each from Spain, France, Sweden, Finland, Australia, and New Zealand. In most cases, the infection was associated with a trip to or near forested areas. The symptoms were fever (n=12), headache (n=6), chills (n=6), nausea (n=4), myalgia (n

  13. The SnSAG merozoite surface antigens of Sarcocystis neurona are expressed differentially during the bradyzoite and sporozoite life cycle stages.

    Science.gov (United States)

    Gautam, A; Dubey, J P; Saville, W J; Howe, D K

    2011-12-29

    Sarcocystis neurona is a two-host coccidian parasite whose complex life cycle progresses through multiple developmental stages differing at morphological and molecular levels. The S. neurona merozoite surface is covered by multiple, related glycosylphosphatidylinositol-linked proteins, which are orthologous to the surface antigen (SAG)/SAG1-related sequence (SRS) gene family of Toxoplasma gondii. Expression of the SAG/SRS proteins in T. gondii and another related parasite Neospora caninum is life-cycle stage specific and seems necessary for parasite transmission and persistence of infection. In the present study, the expression of S. neurona merozoite surface antigens (SnSAGs) was evaluated in the sporozoite and bradyzoite stages. Western blot analysis was used to compare SnSAG expression in merozoites versus sporozoites, while immunocytochemistry was performed to examine expression of the SnSAGs in merozoites versus bradyzoites. These analyses revealed that SnSAG2, SnSAG3 and SnSAG4 are expressed in sporozoites, while SnSAG5 was appeared to be downregulated in this life cycle stage. In S. neurona bradyzoites, it was found that SnSAG2, SnSAG3, SnSAG4 and SnSAG5 were either absent or expression was greatly reduced. As shown for T. gondii, stage-specific expression of the SnSAGs may be important for the parasite to progress through its developmental stages and complete its life cycle successfully. Thus, it is possible that the SAG switching mechanism by these parasites could be exploited as a point of intervention. As well, the alterations in surface antigen expression during different life cycle stages may need to be considered when designing prospective approaches for protective vaccination. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Factors influencing the development of Plasmodium gallinaceum in Aedes fluviatilis

    Directory of Open Access Journals (Sweden)

    Mariana V. Tasón de Camargo

    1983-03-01

    Full Text Available Aedes fluviatilis is susceptible to infection by Plasmodium gallinaceum and is a convenient insect host for the malaria parasite in countries where Aedees aegypti cannot be maintained in laboratories. In South America, for instance, the rearing of A. aegypti the main vector of urban yellow fever, is not advaisable because of the potential health hazard it represents. Our results of the comparative studies carried out between the sporogonic cycle produced with two lines of P. gallinaceum parasites into A. fuviatilis were as follows. As proved for A. aegypti, mosquito infection rates were variable when A. fluviatilis blood-fed on chicks infected with and old syringe-passaged strain of P. gallinaceum. Oocysts developed in 41% of those mosquitos and the mean peak of oocyst production was 56 per stomach. Salivary gland infections developed in about 6% of the mosquitos. The course of sporogony was unrelated to the size of the inoculum administered to chicks or to the route by which the birds were infected. The development of infected salivary glands was unrelated to oocyst production. Sporogony of P. gallinaceum was more uniform when mosquitos blood-fed on chicks infected with a sporozoite-passaged strain. Oocysts developed in about 50% of those mosquitoes and the mean peak of oocyst production was 138 per stomach, with some individuals having as many as 600-800 oocysts. Infected salivary glands developed in a mean of 27% of the mosquitos but, in some batches, was a high as 50%. Patterns of salivary gland parasitism were similar to those of oocyst production. The course of sporogony of P. gallinaceum in A. fluviatilis is analized in relation to degree of parasitemia and gametocytemia in the vertebrate host.Aedes fluviatilis é susceptível à infecção por Plasmodium gallinaceum, sendo considerado um modelo experimental útil para esta infecção em regiões nas quais Aedes aegypti não deve ser criado em laboratório, por razões de segurança. Na

  15. Discovering regulatory motifs in the Plasmodium genome using comparative genomics

    OpenAIRE

    Wu, Jie; Sieglaff, Douglas H.; Gervin, Joshua; Xie, Xiaohui S.

    2008-01-01

    Motivation: Understanding gene regulation in Plasmodium, the causative agent of malaria, is an important step in deciphering its complex life cycle as well as leading to possible new targets for therapeutic applications. Very little is known about gene regulation in Plasmodium, and in particular, few regulatory elements have been identified. Such discovery has been significantly hampered by the high A-T content of some of the genomes of Plasmodium species, as well as the challenge in associat...

  16. In vitro and ex vivo activity of an Azadirachta indica A.Juss. seed kernel extract on early sporogonic development of Plasmodium in comparison with azadirachtin A, its most abundant constituent.

    Science.gov (United States)

    Dahiya, Nisha; Chianese, Giuseppina; Abay, Solomon Mequanente; Taglialatela-Scafati, Orazio; Esposito, Fulvio; Lupidi, Giulio; Bramucci, Massimo; Quassinti, Luana; Christophides, George; Habluetzel, Annette; Lucantoni, Leonardo

    2016-12-15

    NeemAzal ® (NA) is a quantified extract from seed kernels of neem, Azadirachta indica A.Juss. (Meliaceae), with a wide spectrum of biological properties, classically ascribed to its limonoid content. NA contains several azadirachtins (A to L), azadirachtin A (AzaA) being its main constituent. AzaA has been shown to inhibit microgamete formation of the rodent malaria parasite Plasmodium berghei, and NA was found to completely inhibit the transmission of Plasmodium berghei to Anopheles stephensi mosquitoes when administered to gametocytemic mice at a corresponding AzaA dose of 50mg/kg before exposure to mosquitoes. The present study was aimed at i) assessing the pharmacodynamics and duration of action of NA and AzaA against P. berghei exflagellation in systemic circulation in mice and ii) elucidating the transmission blocking activity (TBA) of the main NA constituents. The NA and AzaA pharmacodynamics on exflagellation were assessed through ex vivo exflagellation assays, while TBA of NA constituents was evaluated through in vitro ookinete development assay. Pharmacodynamics experiments: Peripheral blood from P. berghei infected BALB/c mice with circulating mature gametocytes, were treated i.p. with 50mg/kg and 100mg/kg pure AzaA and with NeemAzal ® (Trifolio-M GmbH) at the corresponding AzaA concentrations. The effect magnitude and duration of action of compounds was estimated by counting exflagellation centers, formed by microgametocytes in process of releasing flagellated gametes, at various time points after treatment in ex vivo exflagellation tests. Ookinete Development Assay: The direct effects of NeemAzal ® and AzaA on ookinete development were measured by fluorescence microscopy after incubation of gametocytemic blood with various concentrations of test substances in microplates for 24h. The exflagellation tests revealed an half-life of NA anti-plasmodial compounds of up to 7h at a NA dose corresponding to 100mg/kg equivalent dose of AzaA. The ookinete

  17. Vaccine efficacy against malaria by the combination of porcine parvovirus-like particles and vaccinia virus vectors expressing CS of Plasmodium.

    Directory of Open Access Journals (Sweden)

    Dolores Rodríguez

    Full Text Available With the aim to develop an efficient and cost-effective approach to control malaria, we have generated porcine parvovirus-like particles (PPV-VLPs carrying the CD8(+ T cell epitope (SYVPSAEQI of the circumsporozoite (CS protein from Plasmodium yoelii fused to the PPV VP2 capsid protein (PPV-PYCS, and tested in prime/boost protocols with poxvirus vectors for efficacy in a rodent malaria model. As a proof-of concept, we have characterized the anti-CS CD8(+ T cell response elicited by these hybrid PPV-VLPs in BALB/c mice after immunizations with the protein PPV-PYCS administered alone or in combination with recombinant vaccinia virus (VACV vectors from the Western Reserve (WR and modified virus Ankara (MVA strains expressing the entire P. yoelii CS protein. The results of different immunization protocols showed that the combination of PPV-PYCS prime/poxvirus boost was highly immunogenic, inducing specific CD8+ T cell responses to CS resulting in 95% reduction in liver stage parasites two days following sporozoite challenge. In contrast, neither the administration of PPV-PYCS alone nor the immunization with the vectors given in the order poxvirus/VLPs was as effective. The immune profile induced by VLPs/MVA boost was associated with polyfunctional and effector memory CD8+ T cell responses. These findings highlight the use of recombinant parvovirus PPV-PYCS particles as priming agents and poxvirus vectors, like MVA, as booster to enhance specific CD8+ T cell responses to Plasmodium antigens and to control infection. These observations are relevant in the design of T cell-inducing vaccines against malaria.

  18. Vaccine efficacy against malaria by the combination of porcine parvovirus-like particles and vaccinia virus vectors expressing CS of Plasmodium.

    Science.gov (United States)

    Rodríguez, Dolores; González-Aseguinolaza, Gloria; Rodríguez, Juan R; Vijayan, Aneesh; Gherardi, Magdalena; Rueda, Paloma; Casal, J Ignacio; Esteban, Mariano

    2012-01-01

    With the aim to develop an efficient and cost-effective approach to control malaria, we have generated porcine parvovirus-like particles (PPV-VLPs) carrying the CD8(+) T cell epitope (SYVPSAEQI) of the circumsporozoite (CS) protein from Plasmodium yoelii fused to the PPV VP2 capsid protein (PPV-PYCS), and tested in prime/boost protocols with poxvirus vectors for efficacy in a rodent malaria model. As a proof-of concept, we have characterized the anti-CS CD8(+) T cell response elicited by these hybrid PPV-VLPs in BALB/c mice after immunizations with the protein PPV-PYCS administered alone or in combination with recombinant vaccinia virus (VACV) vectors from the Western Reserve (WR) and modified virus Ankara (MVA) strains expressing the entire P. yoelii CS protein. The results of different immunization protocols showed that the combination of PPV-PYCS prime/poxvirus boost was highly immunogenic, inducing specific CD8+ T cell responses to CS resulting in 95% reduction in liver stage parasites two days following sporozoite challenge. In contrast, neither the administration of PPV-PYCS alone nor the immunization with the vectors given in the order poxvirus/VLPs was as effective. The immune profile induced by VLPs/MVA boost was associated with polyfunctional and effector memory CD8+ T cell responses. These findings highlight the use of recombinant parvovirus PPV-PYCS particles as priming agents and poxvirus vectors, like MVA, as booster to enhance specific CD8+ T cell responses to Plasmodium antigens and to control infection. These observations are relevant in the design of T cell-inducing vaccines against malaria.

  19. The sub-genera of Avian Plasmodium

    Directory of Open Access Journals (Sweden)

    Landau I.

    2010-03-01

    Full Text Available The study of the morphology of a species of Plasmodium is difficult because these organisms have relatively few characters. The size of the schizont, for example, which is easy to assess is important at the specific level but is not always of great phylogenetic significance. Factors reflecting the parasite’s metabolism provide more important evidence. Thus the position of the parasite within the host red cell (attachment to the host nucleus or its membrane, at one end or aligned with it has been shown to be constant for a given species. Another structure of essential significance that is often ignored is a globule, usually refringent in nature, that was first described in Plasmodium vaughani Novy & MacNeal, 1904 and that we consider to be characteristic of the sub-genus Novyella. Species without this structure, previously classified in this sub-genus, are now included in the new sub-genus Papernaia n. sg.

  20. Das Selenoproteom des Malariaerregers Plasmodium falciparum

    OpenAIRE

    Röseler, Anne

    2010-01-01

    Die Protozoen des Genus Plasmodium verursachen weltweit rund 247 Millionen Malariafälle jedes Jahr. Da der Malariaparasit schnell und effektiv Resistenzen gegen neue Antimalaria-Medikamente entwickelt, ist es notwendig, stets innovative Wirkstoffe zu finden. Dabei spielen das Verständnis der grundlegenden Stoffwechselfunktionen und die Entdeckung neuer potenzieller drug targets wichtige Rollen in der präklinischen Forschung. Während ihrer Lebensphasen in menschlichen Erythrozyten und dem ...

  1. An alternative method for Plasmodium culture synchronization.

    Science.gov (United States)

    Lelièvre, J; Berry, A; Benoit-Vical, F

    2005-03-01

    Since the synchronization of Plasmodium falciparum has become an essential tool in research, we have investigated the use of a commercial gelatine solution, Plasmion, to replace Plasmagel, which is now difficult to obtain. This method also avoids the use of techniques based on Percoll-glucose gradients. The Plasmion-based technique proved to be a good method and could become an alternative to Plasmagel.

  2. The disruption of GDP-fucose de novo biosynthesis suggests the presence of a novel fucose-containing glycoconjugate in Plasmodium asexual blood stages.

    Science.gov (United States)

    Sanz, Sílvia; López-Gutiérrez, Borja; Bandini, Giulia; Damerow, Sebastian; Absalon, Sabrina; Dinglasan, Rhoel R; Samuelson, John; Izquierdo, Luis

    2016-11-16

    Glycosylation is an important posttranslational protein modification in all eukaryotes. Besides glycosylphosphatidylinositol (GPI) anchors and N-glycosylation, O-fucosylation has been recently reported in key sporozoite proteins of the malaria parasite. Previous analyses showed the presence of GDP-fucose (GDP-Fuc), the precursor for all fucosylation reactions, in the blood stages of Plasmodium falciparum. The GDP-Fuc de novo pathway, which requires the action of GDP-mannose 4,6-dehydratase (GMD) and GDP-L-fucose synthase (FS), is conserved in the parasite genome, but the importance of fucose metabolism for the parasite is unknown. To functionally characterize the pathway we generated a PfGMD mutant and analyzed its phenotype. Although the labelling by the fucose-binding Ulex europaeus agglutinin I (UEA-I) was completely abrogated, GDP-Fuc was still detected in the mutant. This unexpected result suggests the presence of an alternative mechanism for maintaining GDP-Fuc in the parasite. Furthermore, PfGMD null mutant exhibited normal growth and invasion rates, revealing that the GDP-Fuc de novo metabolic pathway is not essential for the development in culture of the malaria parasite during the asexual blood stages. Nonetheless, the function of this metabolic route and the GDP-Fuc pool that is generated during this stage may be important for gametocytogenesis and sporogonic development in the mosquito.

  3. The disruption of GDP-fucose de novo biosynthesis suggests the presence of a novel fucose-containing glycoconjugate in Plasmodium asexual blood stages

    Science.gov (United States)

    Sanz, Sílvia; López-Gutiérrez, Borja; Bandini, Giulia; Damerow, Sebastian; Absalon, Sabrina; Dinglasan, Rhoel R.; Samuelson, John; Izquierdo, Luis

    2016-01-01

    Glycosylation is an important posttranslational protein modification in all eukaryotes. Besides glycosylphosphatidylinositol (GPI) anchors and N-glycosylation, O-fucosylation has been recently reported in key sporozoite proteins of the malaria parasite. Previous analyses showed the presence of GDP-fucose (GDP-Fuc), the precursor for all fucosylation reactions, in the blood stages of Plasmodium falciparum. The GDP-Fuc de novo pathway, which requires the action of GDP-mannose 4,6-dehydratase (GMD) and GDP-L-fucose synthase (FS), is conserved in the parasite genome, but the importance of fucose metabolism for the parasite is unknown. To functionally characterize the pathway we generated a PfGMD mutant and analyzed its phenotype. Although the labelling by the fucose-binding Ulex europaeus agglutinin I (UEA-I) was completely abrogated, GDP-Fuc was still detected in the mutant. This unexpected result suggests the presence of an alternative mechanism for maintaining GDP-Fuc in the parasite. Furthermore, PfGMD null mutant exhibited normal growth and invasion rates, revealing that the GDP-Fuc de novo metabolic pathway is not essential for the development in culture of the malaria parasite during the asexual blood stages. Nonetheless, the function of this metabolic route and the GDP-Fuc pool that is generated during this stage may be important for gametocytogenesis and sporogonic development in the mosquito. PMID:27849032

  4. Translational Control in Plasmodium and Toxoplasma Parasites

    Science.gov (United States)

    Joyce, Bradley R.; Sullivan, William J.; Nussenzweig, Victor

    2013-01-01

    The life cycles of apicomplexan parasites such as Plasmodium spp. and Toxoplasma gondii are complex, consisting of proliferative and latent stages within multiple hosts. Dramatic transformations take place during the cycles, and they demand precise control of gene expression at all levels, including translation. This review focuses on the mechanisms that regulate translational control in Plasmodium and Toxoplasma, with a particular emphasis on the phosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2α). Phosphorylation of eIF2α (eIF2α∼P) is a conserved mechanism that eukaryotic cells use to repress global protein synthesis while enhancing gene-specific translation of a subset of mRNAs. Elevated levels of eIF2α∼P have been observed during latent stages in both Toxoplasma and Plasmodium, indicating that translational control plays a role in maintaining dormancy. Parasite-specific eIF2α kinases and phosphatases are also required for proper developmental transitions and adaptation to cellular stresses encountered during the life cycle. Identification of small-molecule inhibitors of apicomplexan eIF2α kinases may selectively interfere with parasite translational control and lead to the development of new therapies to treat malaria and toxoplasmosis. PMID:23243065

  5. Translational control in Plasmodium and toxoplasma parasites.

    Science.gov (United States)

    Zhang, Min; Joyce, Bradley R; Sullivan, William J; Nussenzweig, Victor

    2013-02-01

    The life cycles of apicomplexan parasites such as Plasmodium spp. and Toxoplasma gondii are complex, consisting of proliferative and latent stages within multiple hosts. Dramatic transformations take place during the cycles, and they demand precise control of gene expression at all levels, including translation. This review focuses on the mechanisms that regulate translational control in Plasmodium and Toxoplasma, with a particular emphasis on the phosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2α). Phosphorylation of eIF2α (eIF2α∼P) is a conserved mechanism that eukaryotic cells use to repress global protein synthesis while enhancing gene-specific translation of a subset of mRNAs. Elevated levels of eIF2α∼P have been observed during latent stages in both Toxoplasma and Plasmodium, indicating that translational control plays a role in maintaining dormancy. Parasite-specific eIF2α kinases and phosphatases are also required for proper developmental transitions and adaptation to cellular stresses encountered during the life cycle. Identification of small-molecule inhibitors of apicomplexan eIF2α kinases may selectively interfere with parasite translational control and lead to the development of new therapies to treat malaria and toxoplasmosis.

  6. Plasmodium vivax: is it changing course?

    International Nuclear Information System (INIS)

    Khan, M.B.; Qadir, A.; Shaheen, N.; Babar, N.F.

    2013-01-01

    Objective: To determine the haematological parameters in patients with Plasmodium vivax malaria. Study Design: Descriptive study. Place and Duration of Study: The study was carried out at the Department of Medicine and Department of Pathology, Military Hospital Rawalpindi, Pakistan from 1st June 2010 to 30th September 2010. Methodology: Two hundred and sixteen patients were with confirmed Plasmodium vivax (P.vivax) infection. Demographic and malariometric data of all patients suffering from P.vivax was collected on a patient data form. The diagnosis of P.vivax malaria was established by peripheral blood film (PBF) and Rapid diagnostic test (RDT). All haematological parameters e.g. white blood cells (WBCs), platelet count, bilirubin levels were noted. Results: The mean age was 25.10 +- 5.35 years. Out of 216 patients 183 patients (84.7%) were males and thirty three patients (15.3%) were females. Thrombocytopenia was found in 186 patients (86.1%). Leucopoenia was noted in 37 patients (17.1%). Anaemia was found in 17 patients (7.8%). Increased bilrubin levels were noted in 65 patients (30%). Increased alanine transaminase levels were present in 32 patients (14.8%). Nine patients had serum creatinine levels more than 1.2 mg/dl (4.1%). Conclusion: Plasmodium vivax malaria although considered benign has the potential to cause serious haematological derangements in affected individuals. (author)

  7. Plasmodium simium/Plasmodium vivax infections in southern brown howler monkeys from the Atlantic Forest

    Directory of Open Access Journals (Sweden)

    Daniela Camargos Costa

    2014-08-01

    Full Text Available Blood infection by the simian parasite, Plasmodium simium, was identified in captive (n = 45, 4.4% and in wild Alouatta clamitans monkeys (n = 20, 35% from the Atlantic Forest of southern Brazil. A single malaria infection was symptomatic and the monkey presented clinical and haematological alterations. A high frequency of Plasmodium vivax-specific antibodies was detected among these monkeys, with 87% of the monkeys testing positive against P. vivax antigens. These findings highlight the possibility of malaria as a zoonosis in the remaining Atlantic Forest and its impact on the epidemiology of the disease.

  8. Salivary IgA against sporozoite-specific embryogenesis-related protein (TgERP) in the study of horizontally transmitted toxoplasmosis via T. gondii oocysts in endemic settings

    Science.gov (United States)

    The prevalence of toxoplasmosis was investigated in endemic settings in Brazil, and calculated by measuring antibodies in two ELISA systems: 1) IgG and IgM from sera tested by commercial conventional ELISA, and 2) IgA, from saliva, and IgG from sera samples tested against a sporozoite-specific prote...

  9. Plasmodium Infection In Man: A Review | Ekpenyong | Animal ...

    African Journals Online (AJOL)

    Plasmodium infection in man is caused by the bite of an infected female Anopheles mosquito. This results in the disease, malaria. Malaria has serious debilitating effects on man. It adversely affectsman's health, strength and productivity. Here, a review of Plasmodium infection in man including the life cycle transmisson, ...

  10. Artemisinin resistance marker of Plasmodium falciparum in Osogbo ...

    African Journals Online (AJOL)

    Artemisinin derivatives constitute a key component of the present-day treatment for Plasmodium falciparum malaria. Resistance with artemisinins is generally associated with S769N point mutation in the sarco-endoplasmic reticulumdependant ATPase6 (SERCA ATPase6) gene of Plasmodium falciparum, few studies have ...

  11. Population genomics diversity of Plasmodium falciparum in malaria ...

    African Journals Online (AJOL)

    Background: Plasmodium falciparum, the most dangerous malaria parasite species to humans remains an important public health concern in Okelele, a rural community in Ilorin, Kwara State, Nigeria. There is however little information about the genetic diversity of Plasmodium falciparum in Nigeria. Objective: To determine ...

  12. Plasmodium vivax cerebral malaria complicated with venous sinus thrombosis in Colombia

    Institute of Scientific and Technical Information of China (English)

    Miguel A Pinzn; Juan C Pineda; Fernando Rosso; Masaru Shinchi; Fabio Bonilla-Abada

    2013-01-01

    Complicated malaria is usually due to Plasmodium falciparum. Nevertheless, Plasmodium vivax is infrequently related with life-threatening complications. Few cases have been reported of severe Plasmodium vivax infection, and most of them from Southeast Asia and India. We report the first case of cerebral malaria due to Plasmodium vivax in Latin America, complicated with sagittal sinus thrombosis and confirmed by a molecular method.

  13. Response to various periods of mechanical stimuli in Physarum plasmodium

    International Nuclear Information System (INIS)

    Umedachi, Takuya; Ito, Kentaro; Kobayashi, Ryo; Ishiguro, Akio; Nakagaki, Toshiyuki

    2017-01-01

    Response to mechanical stimuli is a fundamental and critical ability for living cells to survive in hazardous conditions or to form adaptive and functional structures against force(s) from the environment. Although this ability has been extensively studied by molecular biology strategies, it is also important to investigate the ability from the viewpoint of biological rhythm phenomena so as to reveal the mechanisms that underlie these phenomena. Here, we use the plasmodium of the true slime mold Physarum polycephalum as the experimental system for investigating this ability. The plasmodium was repetitively stretched for various periods during which its locomotion speed was observed. Since the plasmodium has inherent oscillation cycles of protoplasmic streaming and thickness variation, how the plasmodium responds to various periods of external stretching stimuli can shed light on the other biological rhythm phenomena. The experimental results show that the plasmodium exhibits response to periodic mechanical stimulation and changes its locomotion speed depending on the period of the stretching stimuli. (paper)

  14. RNA-Seq analysis during the life cycle of Cryptosporidium parvum reveals significant differential gene expression between proliferating stages in the intestine and infectious sporozoites.

    Science.gov (United States)

    Lippuner, Christoph; Ramakrishnan, Chandra; Basso, Walter U; Schmid, Marc W; Okoniewski, Michal; Smith, Nicholas C; Hässig, Michael; Deplazes, Peter; Hehl, Adrian B

    2018-05-01

    Cryptosporidium parvum is a major cause of diarrhoea in humans and animals. There are no vaccines and few drugs available to control C. parvum. In this study, we used RNA-Seq to compare gene expression in sporozoites and intracellular stages of C. parvum to identify genes likely to be important for successful completion of the parasite's life cycle and, thereby, possible targets for drugs or vaccines. We identified 3774 protein-encoding transcripts in C. parvum. Applying a stringent cut-off of eight fold for determination of differential expression, we identified 173 genes (26 coding for predicted secreted proteins) upregulated in sporozoites. On the other hand, expression of 1259 genes was upregulated in intestinal stages (merozoites/gamonts) with a gene ontology enrichment for 63 biological processes and upregulation of 117 genes in 23 metabolic pathways. There was no clear stage specificity of expression of AP2-domain containing transcription factors, although sporozoites had a relatively small repertoire of these important regulators. Our RNA-Seq analysis revealed a new calcium-dependent protein kinase, bringing the total number of known calcium-dependent protein kinases (CDPKs) in C. parvum to 11. One of these, CDPK1, was expressed in all stages, strengthening the notion that it is a valid drug target. By comparing parasites grown in vivo (which produce bona fide thick-walled oocysts) and in vitro (which are arrested in sexual development prior to oocyst generation) we were able to confirm that genes encoding oocyst wall proteins are expressed in gametocytes and that the proteins are stockpiled rather than generated de novo in zygotes. RNA-Seq analysis of C. parvum revealed genes expressed in a stage-specific manner and others whose expression is required at all stages of development. The functional significance of these can now be addressed through recent advances in transgenics for C. parvum, and may lead to the identification of viable drug and vaccine

  15. Perfil clínico y parasitológico de la malaria por Plasmodium falciparum y Plasmodium vivax no complicada en Córdoba, Colombia.

    OpenAIRE

    Angélica Knudson Ospina; Ricardo Sánchez Pedraza; Manuel Alberto Pérez Mazorra; Liliana Jazmín Cortés Cortés; Ángela Patricia Guerra Vega; Rubén Santiago Nicholls Orejuela

    2015-01-01

    Antecedentes. En Colombia existen pocos estudios que buscan encontrar diferencias clínicas y parasitológicas en la malaria causada por Plasmodium falciparum y Plasmodium vivax.  Objetivo. Describir el perfil clínico y parasitológico de las malarias por Plasmodium falciparum y Plasmodium vivax no complicadas en Tierralta, Córdoba, Colombia. Materiales y métodos. Se evaluaron pacientes con paludismo no complicado por Plasmodium falciparum y Plasmodium vivax según los protocolos estandariz...

  16. Prevalence of Malaria Plasmodium in Abeokuta, Nigeria

    Directory of Open Access Journals (Sweden)

    Okonko, I. O.

    2009-01-01

    Full Text Available This study reports the prevalence of malaria caused by plasmodium between genders in Abeokuta, the capital city of Ogun State located in the forest zone of southwestern Nigeria between January 2002 and December 2004. Blood film examination for malaria parasites in 708 patients; 366 males and 342 females. Microscopic examination of thick films techniques was employed for this study. Of the 708 (100% patients examined, 577 (81.5% were Plasmodium-positive. A high malaria parasite prevalence rate of 81.5% was noted in this study. Female subjects were more infected (42.4% than males (41.9% however, there was no significant difference in the sex of the subjects studied (p=0.05. A high malaria parasite prevalence rate of 86.9% was noted in samples collected in year 2003 than in other years studied. There was significant difference in the years under study (p=0.05. This study shows that a good percentage of people were infested by malaria Plasmodium. This could be attributed to lack of adequate accommodation and poor sanitary conditions in the area under study. Although several efforts have been made to effectively control the high incidence of malaria in Nigeria, these have been largely unsuccessful due to a number of reasons such as irrigated urban agriculture which can be the malaria vector’s breeding ground in the city, stagnant gutters and swamps in our environment where mosquitoes breed in millions, and lack of political will and commitment of the government in its disease management program, low awareness of the magnitude of malaria problem, poor health practices by individuals and communities and resistance to drugs. Therefore, future interventions in Nigeria should be directed toward controlling malaria in the context of a moderate transmission setting; thus, large-scale distribution of insecticide-treated nets or widespread use of indoor residual spraying may be less cost-effective than enhanced surveillance with effective case management or

  17. Quantitative analysis of Plasmodium ookinete motion in three dimensions suggests a critical role for cell shape in the biomechanics of malaria parasite gliding motility.

    Science.gov (United States)

    Kan, Andrey; Tan, Yan-Hong; Angrisano, Fiona; Hanssen, Eric; Rogers, Kelly L; Whitehead, Lachlan; Mollard, Vanessa P; Cozijnsen, Anton; Delves, Michael J; Crawford, Simon; Sinden, Robert E; McFadden, Geoffrey I; Leckie, Christopher; Bailey, James; Baum, Jake

    2014-05-01

    Motility is a fundamental part of cellular life and survival, including for Plasmodium parasites--single-celled protozoan pathogens responsible for human malaria. The motile life cycle forms achieve motility, called gliding, via the activity of an internal actomyosin motor. Although gliding is based on the well-studied system of actin and myosin, its core biomechanics are not completely understood. Currently accepted models suggest it results from a specifically organized cellular motor that produces a rearward directional force. When linked to surface-bound adhesins, this force is passaged to the cell posterior, propelling the parasite forwards. Gliding motility is observed in all three life cycle stages of Plasmodium: sporozoites, merozoites and ookinetes. However, it is only the ookinetes--formed inside the midgut of infected mosquitoes--that display continuous gliding without the necessity of host cell entry. This makes them ideal candidates for invasion-free biomechanical analysis. Here we apply a plate-based imaging approach to study ookinete motion in three-dimensional (3D) space to understand Plasmodium cell motility and how movement facilitates midgut colonization. Using single-cell tracking and numerical analysis of parasite motion in 3D, our analysis demonstrates that ookinetes move with a conserved left-handed helical trajectory. Investigation of cell morphology suggests this trajectory may be based on the ookinete subpellicular cytoskeleton, with complementary whole and subcellular electron microscopy showing that, like their motion paths, ookinetes share a conserved left-handed corkscrew shape and underlying twisted microtubular architecture. Through comparisons of 3D movement between wild-type ookinetes and a cytoskeleton-knockout mutant we demonstrate that perturbation of cell shape changes motion from helical to broadly linear. Therefore, while the precise linkages between cellular architecture and actomyosin motor organization remain unknown, our

  18. In-depth comparative analysis of malaria parasite genomes reveals protein-coding genes linked to human disease in Plasmodium falciparum genome.

    Science.gov (United States)

    Liu, Xuewu; Wang, Yuanyuan; Liang, Jiao; Wang, Luojun; Qin, Na; Zhao, Ya; Zhao, Gang

    2018-05-02

    Plasmodium falciparum is the most virulent malaria parasite capable of parasitizing human erythrocytes. The identification of genes related to this capability can enhance our understanding of the molecular mechanisms underlying human malaria and lead to the development of new therapeutic strategies for malaria control. With the availability of several malaria parasite genome sequences, performing computational analysis is now a practical strategy to identify genes contributing to this disease. Here, we developed and used a virtual genome method to assign 33,314 genes from three human malaria parasites, namely, P. falciparum, P. knowlesi and P. vivax, and three rodent malaria parasites, namely, P. berghei, P. chabaudi and P. yoelii, to 4605 clusters. Each cluster consisted of genes whose protein sequences were significantly similar and was considered as a virtual gene. Comparing the enriched values of all clusters in human malaria parasites with those in rodent malaria parasites revealed 115 P. falciparum genes putatively responsible for parasitizing human erythrocytes. These genes are mainly located in the chromosome internal regions and participate in many biological processes, including membrane protein trafficking and thiamine biosynthesis. Meanwhile, 289 P. berghei genes were included in the rodent parasite-enriched clusters. Most are located in subtelomeric regions and encode erythrocyte surface proteins. Comparing cluster values in P. falciparum with those in P. vivax and P. knowlesi revealed 493 candidate genes linked to virulence. Some of them encode proteins present on the erythrocyte surface and participate in cytoadhesion, virulence factor trafficking, or erythrocyte invasion, but many genes with unknown function were also identified. Cerebral malaria is characterized by accumulation of infected erythrocytes at trophozoite stage in brain microvascular. To discover cerebral malaria-related genes, fast Fourier transformation (FFT) was introduced to extract

  19. Mosquito abundance, bed net coverage and other factors associated with variations in sporozoite infectivity rates in four villages of rural Tanzania

    DEFF Research Database (Denmark)

    Kweka, Eliningaya J; Nkya, Watoky M M; Mahande, Aneth M

    2008-01-01

    . Sporozoite infectivity rates, mosquito host blood meal source, bed net coverage and mosquito abundance were assessed in this study. METHODOLOGY: A longitudinal survey was conducted in four villages in two regions of Tanzania. Malaria vectors were sampled using the CDC light trap and pyrethrum spray catch...... methods. In each village, ten paired houses were selected for mosquitoes sampling. Sampling was done in fortnight case and study was undertaken for six months in both Kilimanjaro (Northern Tanzania) and Dodoma (Central Tanzania) regions. RESULTS: A total of 6,883 mosquitoes were collected including: 5......,628 (81.8%) Anopheles arabiensis, 1,100 (15.9%) Culex quinquefasciatus, 89 (1.4%) Anopheles funestus, and 66 (0.9%) Anopheles gambiae s.s. Of the total mosquitoes collected 3,861 were captured by CDC light trap and 3,022 by the pyrethrum spray catch method. The overall light trap: spray catch ratio was 1...

  20. An early burst of IFN-γ induced by the pre-erythrocytic stage favours Plasmodium yoelii parasitaemia in B6 mice

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    Barbier Eliane

    2009-06-01

    Full Text Available Abstract Background In murine models of malaria, an early proinflammatory response has been associated with the resolution of blood-stage infection. To dissect the protective immune mechanims that allow the control of parasitaemia, the early immune response of C57BL/6 mice induced during a non-lethal plasmodial infection was analysed. Methods Mice were infected with Plasmodium yoelii 265BY sporozoites, the natural invasive form of the parasite, in order to complete its full life cycle. The concentrations of three proinflammatory cytokines in the sera of mice were determined by ELISA at different time points of infection. The contribution of the liver and the spleen to this cytokinic response was evaluated and the cytokine-producing lymphocytes were identified by flow cytometry. The physiological relevance of these results was tested by monitoring parasitaemia in genetically deficient C57BL/6 mice or wild-type mice treated with anti-cytokine neutralizing antibody. Finally, the cytokinic response in sera of mice infected with parasitized-RBCs was analysed. Results The early immune response of C57BL/6 mice to sporozoite-induced malaria is characterized by a peak of IFN-γ in the serum at day 5 of infection and splenic CD4 T lymphocytes are the major producer of this cytokine at this time point. Somewhat unexpected, the parasitaemia is significantly lower in P. yoelii-infected mice in the absence of IFN-γ. More precisely, at early time points of infection, IFN-γ favours parasitaemia, whereas helping to clear efficiently the blood-stage parasites at later time points. Interestingly, the early IFN-γ burst is induced by the pre-erythrocytic stage. Conclusion These results challenge the current view regarding the role of IFN-γ on the control of parasite growth since they show that IFN-γ is not an essential mediator of protection in P. yoelii-infected C57BL/6 mice. Moreover, the mice parasitaemia is more efficiently controlled in the absence of an

  1. Relative Abundance and Plasmodium Infection Rates of Malaria Vectors in and around Jabalpur, a Malaria Endemic Region in Madhya Pradesh State, Central India.

    Science.gov (United States)

    Singh, Neeru; Mishra, Ashok K; Chand, Sunil K; Bharti, Praveen K; Singh, Mrigendra P; Nanda, Nutan; Singh, Om P; Sodagiri, Kranti; Udhyakumar, Venkatachalam

    2015-01-01

    This study was undertaken in two Primary Health Centers (PHCs) of malaria endemic district Jabalpur in Madhya Pradesh (Central India). In this study we had investigated the relative frequencies of the different anopheline species collected within the study areas by using indoor resting catches, CDC light trap and human landing methods. Sibling species of malaria vectors were identified by cytogenetic and molecular techniques. The role of each vector and its sibling species in the transmission of the different Plasmodium species was ascertained by using sporozoite ELISA. A total of 52,857 specimens comprising of 17 anopheline species were collected by three different methods (39,964 by indoor resting collections, 1059 by human landing and 11,834 by CDC light trap). Anopheles culicifacies was most predominant species in all collections (55, 71 and 32% in indoor resting, human landing and light trap collections respectively) followed by An. subpictus and An. annularis. All five sibling species of An. culicifacies viz. species A, B, C, D and E were found while only species T and S of An. fluviatilis were collected. The overall sporozoite rate in An. culicifacies and An. fluviatilis were 0.42% (0.25% for P. falciparum and 0.17% for P. vivax) and 0.90% (0.45% for P. falciparum and 0.45% for P. vivax) respectively. An. culicifacies and An. fluviatilis were found harbouring both P. vivax variants VK-210 and VK-247, and P. falciparum. An. culicifacies sibling species C and D were incriminated as vectors during most part of the year while sibling species T of An. fluviatilis was identified as potential vector in monsoon and post monsoon season. An. culicifacies species C (59%) was the most abundant species followed by An. culicifacies D (24%), B (8.7%), E (6.7%) and A (1.5%). Among An. fluviatilis sibling species, species T was common (99%) and only few specimens of S were found. Our study provides crucial information on the prevalence of An. culicifacies and An. fluviatilis

  2. Relative Abundance and Plasmodium Infection Rates of Malaria Vectors in and around Jabalpur, a Malaria Endemic Region in Madhya Pradesh State, Central India.

    Directory of Open Access Journals (Sweden)

    Neeru Singh

    Full Text Available This study was undertaken in two Primary Health Centers (PHCs of malaria endemic district Jabalpur in Madhya Pradesh (Central India.In this study we had investigated the relative frequencies of the different anopheline species collected within the study areas by using indoor resting catches, CDC light trap and human landing methods. Sibling species of malaria vectors were identified by cytogenetic and molecular techniques. The role of each vector and its sibling species in the transmission of the different Plasmodium species was ascertained by using sporozoite ELISA.A total of 52,857 specimens comprising of 17 anopheline species were collected by three different methods (39,964 by indoor resting collections, 1059 by human landing and 11,834 by CDC light trap. Anopheles culicifacies was most predominant species in all collections (55, 71 and 32% in indoor resting, human landing and light trap collections respectively followed by An. subpictus and An. annularis. All five sibling species of An. culicifacies viz. species A, B, C, D and E were found while only species T and S of An. fluviatilis were collected. The overall sporozoite rate in An. culicifacies and An. fluviatilis were 0.42% (0.25% for P. falciparum and 0.17% for P. vivax and 0.90% (0.45% for P. falciparum and 0.45% for P. vivax respectively. An. culicifacies and An. fluviatilis were found harbouring both P. vivax variants VK-210 and VK-247, and P. falciparum. An. culicifacies sibling species C and D were incriminated as vectors during most part of the year while sibling species T of An. fluviatilis was identified as potential vector in monsoon and post monsoon season.An. culicifacies species C (59% was the most abundant species followed by An. culicifacies D (24%, B (8.7%, E (6.7% and A (1.5%. Among An. fluviatilis sibling species, species T was common (99% and only few specimens of S were found. Our study provides crucial information on the prevalence of An. culicifacies and An

  3. Perfil clínico y parasitológico de la malaria por Plasmodium falciparum y Plasmodium vivax no complicada en Córdoba, Colombia.

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    Angélica Knudson Ospina

    2015-10-01

    Conclusión. Se identificaron algunas diferencias clínicas entre los enfermos con Plasmodium vivax y los enfermos con Plasmodium falciparum, y las variables estudiadas se agruparon en cuatro perfiles que permiten una variedad de interpretaciones.

  4. The shape of the iceberg: quantification of submicroscopic Plasmodium falciparum and Plasmodium vivax parasitaemia and gametocytaemia in five low endemic settings in Ethiopia

    NARCIS (Netherlands)

    Tadesse, F.G.; Hoogen, L. van den; Lanke, K.H.; Schildkraut, J.; Tetteh, K.; Aseffa, A.; Mamo, H.; Sauerwein, R.; Felger, I.; Drakeley, C.; Gadissa, E.; Bousema, T.

    2017-01-01

    BACKGROUND: The widespread presence of low-density asymptomatic infections with concurrent gametocytes may be a stumbling block for malaria elimination. This study investigated the asymptomatic reservoir of Plasmodium falciparum and Plasmodium vivax infections in schoolchildren from five settings in

  5. Mosquito transmission of the rodent malaria parasite Plasmodium chabaudi

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    Spence Philip J

    2012-12-01

    Full Text Available Abstract Background Serial blood passage of Plasmodium increases virulence, whilst mosquito transmission inherently regulates parasite virulence within the mammalian host. It is, therefore, imperative that all aspects of experimental malaria research are studied in the context of the complete Plasmodium life cycle. Methods Plasmodium chabaudi chabaudi displays many characteristics associated with human Plasmodium infection of natural mosquito vectors and the mammalian host, and thus provides a unique opportunity to study the pathogenesis of malaria in a single infection setting. An optimized protocol that permits efficient and reproducible vector transmission of P. c. chabaudi via Anopheles stephensi was developed. Results and conclusions This protocol was utilized for mosquito transmission of genetically distinct P. c. chabaudi isolates, highlighting differential parasite virulence within the mosquito vector and the spectrum of host susceptibility to infection initiated via the natural route, mosquito bite. An apposite experimental system in which to delineate the pathogenesis of malaria is described in detail.

  6. Cryo scanning electron microscopy of Plasmodium falciparum-infected erythrocytes

    DEFF Research Database (Denmark)

    Hempel, Casper

    2017-01-01

    Plasmodium falciparum invades erythrocytes as an essential part of their life cycle. While living inside erythrocytes, the parasite remodels the cell's intracellular organization as well as its outer surface. Late trophozoite-stage parasites and schizonts introduce numerous small protrusions...

  7. Seasonal variations in antibody response to a Plasmodium ...

    African Journals Online (AJOL)

    An Enzyme Linked Immunosorbent Assay (ELISA), employing a recombinant peptide capture antigen (R32tet32) was used to detect antibodies against the circumsporozoite protein (CSP) of the malaria parasite, Plasmodium falciparum in 169 ...

  8. Impact of Plasmodium falciparum and hookworm infections on the ...

    African Journals Online (AJOL)

    abp

    2013-01-18

    Saharan Africa and they increase the prevalence of anaemia in pregnancy with resultant poor pregnancy outcomes. This study was carried out to assess the impact of Plasmodium falciparum and hookworm infections on.

  9. Peripheral blood cell signatures of Plasmodium falciparum infection during pregnancy

    DEFF Research Database (Denmark)

    Ibitokou, Samad; Oesterholt, Mayke; Brutus, Laurent

    2012-01-01

    Sequestration of Plasmodium falciparum-infected erythrocytes in placental intervillous spaces causes inflammation and pathology. Knowledge of the profiles of immune cells associated with the physiopathology of pregnancy-associated malaria (PAM) is scarce. We conducted a longitudinal, prospective ...

  10. IN-VITRO EVALUATION OF P AGAINST Plasmodium falcipa ...

    African Journals Online (AJOL)

    userpc

    researched protective vaccine for the diseas but there are ... o growth of plasmodium falciparum in asexual erythrocyte stage a of fourteen .... different brands specified by W.H.O were purchased ... Preparation of the thin smear was carried out.

  11. Fine-scale genetic characterization of Plasmodium falciparum ...

    Indian Academy of Sciences (India)

    RESEARCH ARTICLE. Fine-scale genetic characterization of Plasmodium falciparum .... Materials and methods. The DNA ... the order and location of genes (as per the PlasmoDB data resources, available at ... There is currently an. Figure 5.

  12. Anti-Plasmodium activity of ceramide analogs

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    Gatt Shimon

    2004-12-01

    Full Text Available Abstract Background Sphingolipids are key molecules regulating many essential functions in eukaryotic cells and ceramide plays a central role in sphingolipid metabolism. A sphingolipid metabolism occurs in the intraerythrocytic stages of Plasmodium falciparum and is associated with essential biological processes. It constitutes an attractive and potential target for the development of new antimalarial drugs. Methods The anti-Plasmodium activity of a series of ceramide analogs containing different linkages (amide, methylene or thiourea linkages between the fatty acid part of ceramide and the sphingoid core was investigated in culture and compared to the sphingolipid analog PPMP (d,1-threo-1-phenyl-2-palmitoylamino-3-morpholino-1-propanol. This analog is known to inhibit the parasite sphingomyelin synthase activity and block parasite development by preventing the formation of the tubovesicular network that extends from the parasitophorous vacuole to the red cell membrane and delivers essential extracellular nutrients to the parasite. Results Analogs containing methylene linkage showed a considerably higher anti-Plasmodium activity (IC50 in the low nanomolar range than PPMP and their counterparts with a natural amide linkage (IC50 in the micromolar range. The methylene analogs blocked irreversibly P. falciparum development leading to parasite eradication in contrast to PPMP whose effect is cytostatic. A high sensitivity of action towards the parasite was observed when compared to their effect on the human MRC-5 cell growth. The toxicity towards parasites did not correlate with the inhibition by methylene analogs of the parasite sphingomyelin synthase activity and the tubovesicular network formation, indicating that this enzyme is not their primary target. Conclusions It has been shown that ceramide analogs were potent inhibitors of P. falciparum growth in culture. Interestingly, the nature of the linkage between the fatty acid part and the

  13. Placental histopathological changes associated with Plasmodium vivax infection during pregnancy.

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    Rodrigo M Souza

    Full Text Available Histological evidence of Plasmodium in the placenta is indicative of placental malaria, a condition associated with severe outcomes for mother and child. Histological lesions found in placentas from Plasmodium-exposed women include syncytial knotting, syncytial rupture, thickening of the placental barrier, necrosis of villous tissue and intervillositis. These histological changes have been associated with P. falciparum infections, but little is known about the contribution of P. vivax to such changes. We conducted a cross-sectional study with pregnant women at delivery and assigned them to three groups according to their Plasmodium exposure during pregnancy: no Plasmodium exposure (n = 41, P. vivax exposure (n = 59 or P. falciparum exposure (n = 19. We evaluated their placentas for signs of Plasmodium and placental lesions using ten histological parameters: syncytial knotting, syncytial rupture, placental barrier thickness, villi necrosis, intervillous space area, intervillous leucocytes, intervillous mononucleates, intervillous polymorphonucleates, parasitized erythrocytes and hemozoin. Placentas from P. vivax-exposed women showed little evidence of Plasmodium or hemozoin but still exhibited more lesions than placentas from women not exposed to Plasmodium, especially when infections occurred twice or more during pregnancy. In the Brazilian state of Acre, where diagnosis and primary treatment are readily available and placental lesions occur in the absence of detected placental parasites, relying on the presence of Plasmodium in the placenta to evaluate Plasmodium-induced placental pathology is not feasible. Multivariate logistic analysis revealed that syncytial knotting (odds ratio [OR], 4.21, P = 0.045, placental barrier thickness (OR, 25.59, P = 0.021 and mononuclear cells (OR, 4.02, P = 0.046 were increased in placentas from P. vivax-exposed women when compared to women not exposed to Plasmodium during pregnancy. A

  14. Mitosis in the Human Malaria Parasite Plasmodium falciparum ▿

    OpenAIRE

    Gerald, Noel; Mahajan, Babita; Kumar, Sanjai

    2011-01-01

    Malaria is caused by intraerythrocytic protozoan parasites belonging to Plasmodium spp. (phylum Apicomplexa) that produce significant morbidity and mortality, mostly in developing countries. Plasmodium parasites have a complex life cycle that includes multiple stages in anopheline mosquito vectors and vertebrate hosts. During the life cycle, the parasites undergo several cycles of extreme population growth within a brief span, and this is critical for their continued transmission and a contri...

  15. Anti-malarial effect of 1-(N-acetyl-6-aminohexyl-3-hydroxy-2-methylpyridin-4-one and green tea extract on erythrocyte-stage Plasmodium berghei in mice

    Directory of Open Access Journals (Sweden)

    Phitsinee Thipubon

    2015-11-01

    Conclusions: CM1 would be effective per se and synergize with PYR in inhibiting growth of murine malaria parasites, possibly by limiting iron supply from plasma transferrin and host PRBC cytoplasm, and chelating catalytic iron cstitutive in parasites’ mitochondrial cytochromes and cytoplasmic ribonucleotide reductase. CM1 would be a promising adjuvant to enhance PYR anti-malarial activity and minimize the drug resistance.

  16. Gametocytogenesis : the puberty of Plasmodium falciparum

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    Ariey Frédéric

    2004-07-01

    Full Text Available Abstract The protozoan Plasmodium falciparum has a complex life cycle in which asexual multiplication in the vertebrate host alternates with an obligate sexual reproduction in the anopheline mosquito. Apart from the apparent recombination advantages conferred by sex, P. falciparum has evolved a remarkable biology and adaptive phenotypes to insure its transmission despite the dangers of sex. This review mainly focuses on the current knowledge on commitment to sexual development, gametocytogenesis and the evolutionary significance of various aspects of gametocyte biology. It goes further than pure biology to look at the strategies used to improve successful transmission. Although gametocytes are inevitable stages for transmission and provide a potential target to fight malaria, they have received less attention than the pathogenic asexual stages. There is a need for research on gametocytes, which are a fascinating stage, responsible to a large extent for the success of P. falciparum.

  17. Plasmodium falciparum drug resistance in Angola.

    Science.gov (United States)

    Fançony, Cláudia; Brito, Miguel; Gil, Jose Pedro

    2016-02-09

    Facing chloroquine drug resistance, Angola promptly adopted artemisinin-based combination therapy as the first-line to treat malaria. Currently, the country aims to consolidate malaria control, while preparing for the elimination of the disease, along with others African countries in the region. However, the remarkable capacity of Plasmodium to develop drug resistance represents an alarming threat for those achievements. Herein, the available, but relatively scarce and dispersed, information on malaria drug resistance in Angola, is reviewed and discussed. The review aims to inform but also to encourage future research studies that monitor and update the information on anti-malarial drug efficacy and prevalence of molecular markers of drug resistance, key fields in the context and objectives of elimination.

  18. Wanted Plasmodium falciparum, dead or alive

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    Fatimata Sow

    2015-07-01

    Full Text Available Mechanisms of cell death in unicellular parasites have been subjects of debate for the last decade, with studies demonstrating evidence of apoptosis or non-apoptosis like mechanisms, including necrosis, and autophagy. Recent clarifications on the definition of regulated or accidental cell death by The Nomenclature Committee on Cell Death provides an opportunity to reanalyze some data, re-evaluate conclusions in the light of parasite diversity, and to propose alternative arguments in the context of malaria drug resistance, considering lack of really new drugs in the pipeline. Deciphering the mechanisms of death may help in detection of new drug targets and the design of innovative drugs. However, classifications have been evolving rapidly since initial description of “programmed cell death”, leading to some uncertainty as to whether Plasmodium cell death is accidental or regulated.

  19. Rheopathologic Consequence of Plasmodium vivax Rosette Formation.

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    Rou Zhang

    2016-08-01

    Full Text Available Malaria parasites dramatically alter the rheological properties of infected red blood cells. In the case of Plasmodium vivax, the parasite rapidly decreases the shear elastic modulus of the invaded RBC, enabling it to avoid splenic clearance. This study highlights correlation between rosette formation and altered membrane deformability of P. vivax-infected erythrocytes, where the rosette-forming infected erythrocytes are significantly more rigid than their non-rosetting counterparts. The adhesion of normocytes to the PvIRBC is strong (mean binding force of 440pN resulting in stable rosette formation even under high physiological shear flow stress. Rosetting may contribute to the sequestration of PvIRBC schizonts in the host microvasculature or spleen.

  20. Epidemiology of Plasmodium vivax Malaria in Peru.

    Science.gov (United States)

    Rosas-Aguirre, Angel; Gamboa, Dionicia; Manrique, Paulo; Conn, Jan E; Moreno, Marta; Lescano, Andres G; Sanchez, Juan F; Rodriguez, Hugo; Silva, Hermann; Llanos-Cuentas, Alejandro; Vinetz, Joseph M

    2016-12-28

    Malaria in Peru, dominated by Plasmodium vivax, remains a public health problem. The 1990s saw newly epidemic malaria emerge, primarily in the Loreto Department in the Amazon region, including areas near to Iquitos, the capital city, but sporadic malaria transmission also occurred in the 1990s-2000s in both north-coastal Peru and the gold mining regions of southeastern Peru. Although a Global Fund-supported intervention (PAMAFRO, 2005-2010) was temporally associated with a decrease of malaria transmission, from 2012 to the present, both P. vivax and Plasmodium falciparum malaria cases have rapidly increased. The Peruvian Ministry of Health continues to provide artemesinin-based combination therapy for microscopy-confirmed cases of P. falciparum and chloroquine-primaquine for P. vivax Malaria transmission continues in remote areas nonetheless, where the mobility of humans and parasites facilitates continued reintroduction outside of ongoing surveillance activities, which is critical to address for future malaria control and elimination efforts. Ongoing P. vivax research gaps in Peru include the following: identification of asymptomatic parasitemics, quantification of the contribution of patent and subpatent parasitemics to mosquito transmission, diagnosis of nonparasitemic hypnozoite carriers, and implementation of surveillance for potential emergence of chloroquine- and 8-aminoquinoline-resistant P. vivax Clinical trials of tafenoquine in Peru have been promising, and glucose-6-phosphate dehydrogenase deficiency in the region has not been observed to be a limitation to its use. Larger-scale challenges for P. vivax (and malaria in general) in Peru include logistical difficulties in accessing remote riverine populations, consequences of government policy and poverty trends, and obtaining international funding for malaria control and elimination. © The American Society of Tropical Medicine and Hygiene.

  1. Elimination of Plasmodium falciparum malaria in Tajikistan.

    Science.gov (United States)

    Kondrashin, Anatoly V; Sharipov, Azizullo S; Kadamov, Dilshod S; Karimov, Saifuddin S; Gasimov, Elkhan; Baranova, Alla M; Morozova, Lola F; Stepanova, Ekaterina V; Turbabina, Natalia A; Maksimova, Maria S; Morozov, Evgeny N

    2017-05-30

    Malaria was eliminated in Tajikistan by the beginning of the 1960s. However, sporadic introduced cases of malaria occurred subsequently probably as a result of transmission from infected mosquito Anopheles flying over river the Punj from the border areas of Afghanistan. During the 1970s and 1980s local outbreaks of malaria were reported in the southern districts bordering Afghanistan. The malaria situation dramatically changed during the 1990s following armed conflict and civil unrest in the newly independent Tajikistan, which paralyzed health services including the malaria control activities and a large-scale malaria epidemic occurred with more than 400,000 malaria cases. The malaria epidemic was contained by 1999 as a result of considerable financial input from the Government and the international community. Although Plasmodium falciparum constituted only about 5% of total malaria cases, reduction of its incidence was slower than that of Plasmodium vivax. To prevent increase in P. falciparum malaria both in terms of incidence and territory, a P. falciparum elimination programme in the Republic was launched in 200, jointly supported by the Government and the Global Fund for control of AIDS, tuberculosis and malaria. The main activities included the use of pyrethroids for the IRS with determined periodicity, deployment of mosquito nets, impregnated with insecticides, use of larvivorous fishes as a biological larvicide, implementation of small-scale environmental management, and use of personal protection methods by population under malaria risk. The malaria surveillance system was strengthened by the use of ACD, PCD, RCD and selective use of mass blood surveys. All detected cases were timely epidemiologically investigated and treated based on the results of laboratory diagnosis. As a result, by 2009, P. falciparum malaria was eliminated from all of Tajikistan, one year ahead of the originally targeted date. Elimination of P. falciparum also contributed towards

  2. Epidemiology of Plasmodium vivax Malaria in Peru

    Science.gov (United States)

    Rosas-Aguirre, Angel; Gamboa, Dionicia; Manrique, Paulo; Conn, Jan E.; Moreno, Marta; Lescano, Andres G.; Sanchez, Juan F.; Rodriguez, Hugo; Silva, Hermann; Llanos-Cuentas, Alejandro; Vinetz, Joseph M.

    2016-01-01

    Malaria in Peru, dominated by Plasmodium vivax, remains a public health problem. The 1990s saw newly epidemic malaria emerge, primarily in the Loreto Department in the Amazon region, including areas near to Iquitos, the capital city, but sporadic malaria transmission also occurred in the 1990s–2000s in both north-coastal Peru and the gold mining regions of southeastern Peru. Although a Global Fund-supported intervention (PAMAFRO, 2005–2010) was temporally associated with a decrease of malaria transmission, from 2012 to the present, both P. vivax and Plasmodium falciparum malaria cases have rapidly increased. The Peruvian Ministry of Health continues to provide artemesinin-based combination therapy for microscopy-confirmed cases of P. falciparum and chloroquine–primaquine for P. vivax. Malaria transmission continues in remote areas nonetheless, where the mobility of humans and parasites facilitates continued reintroduction outside of ongoing surveillance activities, which is critical to address for future malaria control and elimination efforts. Ongoing P. vivax research gaps in Peru include the following: identification of asymptomatic parasitemics, quantification of the contribution of patent and subpatent parasitemics to mosquito transmission, diagnosis of nonparasitemic hypnozoite carriers, and implementation of surveillance for potential emergence of chloroquine- and 8-aminoquinoline-resistant P. vivax. Clinical trials of tafenoquine in Peru have been promising, and glucose-6-phosphate dehydrogenase deficiency in the region has not been observed to be a limitation to its use. Larger-scale challenges for P. vivax (and malaria in general) in Peru include logistical difficulties in accessing remote riverine populations, consequences of government policy and poverty trends, and obtaining international funding for malaria control and elimination. PMID:27799639

  3. CD8+ T cells from a novel T cell receptor transgenic mouse induce liver-stage immunity that can be boosted by blood-stage infection in rodent malaria.

    Directory of Open Access Journals (Sweden)

    Lei Shong Lau

    2014-05-01

    Full Text Available To follow the fate of CD8+ T cells responsive to Plasmodium berghei ANKA (PbA infection, we generated an MHC I-restricted TCR transgenic mouse line against this pathogen. T cells from this line, termed PbT-I T cells, were able to respond to blood-stage infection by PbA and two other rodent malaria species, P. yoelii XNL and P. chabaudi AS. These PbT-I T cells were also able to respond to sporozoites and to protect mice from liver-stage infection. Examination of the requirements for priming after intravenous administration of irradiated sporozoites, an effective vaccination approach, showed that the spleen rather than the liver was the main site of priming and that responses depended on CD8α+ dendritic cells. Importantly, sequential exposure to irradiated sporozoites followed two days later by blood-stage infection led to augmented PbT-I T cell expansion. These findings indicate that PbT-I T cells are a highly versatile tool for studying multiple stages and species of rodent malaria and suggest that cross-stage reactive CD8+ T cells may be utilized in liver-stage vaccine design to enable boosting by blood-stage infections.

  4. Establishment of an In Vitro Assay for Assessing the Effects of Drugs on the Liver Stages of Plasmodium vivax Malaria

    Science.gov (United States)

    2010-06-01

    health and economies of the developing world has been dramatically underestimated. Pv has a unique feature in its life cycle . Uninucleate sporozoites (spz...severe symptoms in Pv infection may be due to the infection with multidrug resistant parasites [7,8]. Pv has a unique feature in its life cycle ...a unique feature in its life cycle . Uninucleate sporozoites (spz), after invasion of human hepatocytes, either proceed to develop into tens of

  5. Primate malarias: Diversity, distribution and insights for zoonotic Plasmodium

    Directory of Open Access Journals (Sweden)

    Christina Faust

    2015-12-01

    Full Text Available Protozoans within the genus Plasmodium are well-known as the causative agents of malaria in humans. Numerous Plasmodium species parasites also infect a wide range of non-human primate hosts in tropical and sub-tropical regions worldwide. Studying this diversity can provide critical insight into our understanding of human malarias, as several human malaria species are a result of host switches from non-human primates. Current spillover of a monkey malaria, Plasmodium knowlesi, in Southeast Asia highlights the permeability of species barriers in Plasmodium. Also recently, surveys of apes in Africa uncovered a previously undescribed diversity of Plasmodium in chimpanzees and gorillas. Therefore, we carried out a meta-analysis to quantify the global distribution, host range, and diversity of known non-human primate malaria species. We used published records of Plasmodium parasites found in non-human primates to estimate the total diversity of non-human primate malarias globally. We estimate that at least three undescribed primate malaria species exist in sampled primates, and many more likely exist in unstudied species. The diversity of malaria parasites is especially uncertain in regions of low sampling such as Madagascar, and taxonomic groups such as African Old World Monkeys and gibbons. Presence–absence data of malaria across primates enables us to highlight the close association of forested regions and non-human primate malarias. This distribution potentially reflects a long coevolution of primates, forest-adapted mosquitoes, and malaria parasites. The diversity and distribution of primate malaria are an essential prerequisite to understanding the mechanisms and circumstances that allow Plasmodium to jump species barriers, both in the evolution of malaria parasites and current cases of spillover into humans.

  6. Comparison of three molecular methods for the detection and speciation of Plasmodium vivax and Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Price Ric N

    2007-09-01

    Full Text Available Abstract Background Accurate diagnosis of Plasmodium spp. is essential for the rational treatment of malaria. Despite its many disadvantages, microscopic examination of blood smears remains the current "gold standard" for malaria detection and speciation. PCR assays offer an alternative to microscopy which has been shown to have superior sensitivity and specificity. Unfortunately few comparative studies have been done on the various molecular based speciation methods. Methods The sensitivity, specificity and cost effectiveness of three molecular techniques were compared for the detection and speciation of Plasmodium falciparum and Plasmodium vivax from dried blood spots collected from 136 patients in western Thailand. The results from the three molecular speciation techniques (nested PCR, multiplex PCR, and real-time PCR were used to develop a molecular consensus (two or more identical PCR results as an alternative gold standard. Results According to the molecular consensus, 9.6% (13/136 of microscopic diagnoses yielded false negative results. Multiplex PCR failed to detect P. vivax in three mixed isolates, and the nested PCR gave a false positive P. falciparum result in one case. Although the real-time PCR melting curve analysis was the most expensive method, it was 100% sensitive and specific and least time consuming of the three molecular techniques investigated. Conclusion Although microscopy remains the most appropriate method for clinical diagnosis in a field setting, its use as a gold standard may result in apparent false positive results by superior techniques. Future studies should consider using more than one established molecular methods as a new gold standard to assess novel malaria diagnostic kits and PCR assays.

  7. From the Macro to the Micro: Gel Mapping to Differentiate between Sporozoites of Two Immunologically Distinct Strains of Eimeria maxima (Strains M6 and Guelph).

    Science.gov (United States)

    El-Ashram, Saeed; Yin, Qing; Liu, Hongbin; Al Nasr, Ibrahim; Liu, Xianyong; Suo, Xun; Barta, John

    2015-01-01

    Two immunologically distinct strains of E. maxima were examined in this study: the M6 strain and the Guelph strain. The differential expression between the sporozoites of the two strains of E. maxima was determined by image analysis of 100 μg of protein from each strain separated by standard one- and conventional two-dimensional polyacrylamide gel electrophoresis. In addition to differences in both molecular weight and the electrophoretic mobility, differences in the intensity of polypeptide bands for example, GS 136.4 and M6 169 were explored. Pooled gels were prepared from each strain. A representative 2D-PAGE gel spanning a non-linear pH range of 3-10 of E. maxima strain M6 consisted of approximately 694 polypeptide spots with about 67 (9.6%) of the polypeptide spots being unique relative to the other strain. E. maxima strain GS had about 696 discernable polypeptide spots with 69 spots (9.9%) that differed from those of the M6 strain. In-depth characterization of the variable polypeptide spots; unique polypeptide spots (absence or presence) and shared polypeptide spots with modifications may lead to novel vaccine target in the form of multi-component, multi-stage, multi-immunovariant strains, multi-species subunit vaccine, and diagnostic probe for E. maxima.

  8. Safety and immunogenicity of a recombinant Plasmodium falciparum AMA1 malaria vaccine adjuvanted with Alhydrogel, Montanide ISA 720 or AS02.

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    Meta Roestenberg

    Full Text Available Plasmodium falciparum Apical Membrane Antigen 1 (PfAMA1 is a candidate vaccine antigen expressed by merozoites and sporozoites. It plays a key role in red blood cell and hepatocyte invasion that can be blocked by antibodies.We assessed the safety and immunogenicity of recombinant PfAMA1 in a dose-escalating, phase Ia trial. PfAMA1 FVO strain, produced in Pichia pastoris, was reconstituted at 10 microg and 50 microg doses with three different adjuvants, Alhydrogel, Montanide ISA720 and AS02 Adjuvant System. Six randomised groups of healthy male volunteers, 8-10 volunteers each, were scheduled to receive three immunisations at 4-week intervals. Safety and immunogenicity data were collected over one year. Transient pain was the predominant injection site reaction (80-100%. Induration occurred in the Montanide 50 microg group, resulting in a sterile abscess in two volunteers. Systemic adverse events occurred mainly in the AS02 groups lasting for 1-2 days. Erythema was observed in 22% of Montanide and 59% of AS02 group volunteers. After the second dose, six volunteers in the AS02 group and one in the Montanide group who reported grade 3 erythema (>50 mm were withdrawn as they met the stopping criteria. All adverse events resolved. There were no vaccine-related serious adverse events. Humoral responses were highest in the AS02 groups. Antibodies showed activity in an in vitro growth inhibition assay up to 80%. Upon stimulation with the vaccine, peripheral mononuclear cells from all groups proliferated and secreted IFNgamma and IL-5 cytokines.All formulations showed distinct reactogenicity profiles. All formulations with PfAMA1 were immunogenic and induced functional antibodies.(Clinicaltrials.gov NCT00730782.

  9. PfeIK1, a eukaryotic initiation factor 2α kinase of the human malaria parasite Plasmodium falciparum, regulates stress-response to amino-acid starvation

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    Ranford-Cartwright Lisa

    2009-05-01

    Full Text Available Abstract Background Post-transcriptional control of gene expression is suspected to play an important role in malaria parasites. In yeast and metazoans, part of the stress response is mediated through phosphorylation of eukaryotic translation initiation factor 2α (eIF2α, which results in the selective translation of mRNAs encoding stress-response proteins. Methods The impact of starvation on the phosphorylation state of PfeIF2α was examined. Bioinformatic methods were used to identify plasmodial eIF2α kinases. The activity of one of these, PfeIK1, was investigated using recombinant protein with non-physiological substrates and recombinant PfeIF2α. Reverse genetic techniques were used to disrupt the pfeik1 gene. Results The data demonstrate that the Plasmodium falciparum eIF2α orthologue is phosphorylated in response to starvation, and provide bioinformatic evidence for the presence of three eIF2α kinases in P. falciparum, only one of which (PfPK4 had been described previously. Evidence is provided that one of the novel eIF2α kinases, PfeIK1, is able to phosphorylate the P. falciparum eIF2α orthologue in vitro. PfeIK1 is not required for asexual or sexual development of the parasite, as shown by the ability of pfeik1- parasites to develop into sporozoites. However, eIF2α phosphorylation in response to starvation is abolished in pfeik1- asexual parasites Conclusion This study strongly suggests that a mechanism for versatile regulation of translation by several kinases with a similar catalytic domain but distinct regulatory domains, is conserved in P. falciparum.

  10. Chimpanzee malaria parasites related to Plasmodium ovale in Africa.

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    Linda Duval

    Full Text Available Since the 1970's, the diversity of Plasmodium parasites in African great apes has been neglected. Surprisingly, P. reichenowi, a chimpanzee parasite, is the only such parasite to have been molecularly characterized. This parasite is closely phylogenetically related to P. falciparum, the principal cause of the greatest malaria burden in humans. Studies of malaria parasites from anthropoid primates may provide relevant phylogenetic information, improving our understanding of the origin and evolutionary history of human malaria species. In this study, we screened 130 DNA samples from chimpanzees (Pan troglodytes and gorillas (Gorilla gorilla from Cameroon for Plasmodium infection, using cytochrome b molecular tools. Two chimpanzees from the subspecies Pan t. troglodytes presented single infections with Plasmodium strains molecularly related to the human malaria parasite P. ovale. These chimpanzee parasites and 13 human strains of P. ovale originated from a various sites in Africa and Asia were characterized using cytochrome b and cytochrome c oxidase 1 mitochondrial partial genes and nuclear ldh partial gene. Consistent with previous findings, two genetically distinct types of P. ovale, classical and variant, were observed in the human population from a variety of geographical locations. One chimpanzee Plasmodium strain was genetically identical, on all three markers tested, to variant P. ovale type. The other chimpanzee Plasmodium strain was different from P. ovale strains isolated from humans. This study provides the first evidence of possibility of natural cross-species exchange of P. ovale between humans and chimpanzees of the subspecies Pan t. troglodytes.

  11. The Fatty Acid Biosynthesis Enzyme FabI Plays a Key Role In the Development of Liver Stage Malarial Parasites

    Science.gov (United States)

    Yu, Min; Santha Kumar, T. R.; Nkrumah, Louis J.; Coppi, Alida; Retzlaff, Silke; Li, Celeste D.; Kelly, Brendan J.; Moura, Pedro A.; Lakshmanan, Viswanathan; Freundlich, Joel S.; Valderramos, Juan-Carlos; Vilcheze, Catherine; Siedner, Mark; Tsai, Jennifer H.-C.; Falkard, Brie; Sidhu, Amar bir Singh; Purcell, Lisa A.; Gratraud, Paul; Kremer, Laurent; Waters, Andy P.; Schiehser, Guy; Jacobus, David P.; Janse, Chris J.; Ager, Arba; Jacobs, William R.; Sacchettini, James C.; Heussler, Volker; Sinnis, Photini; Fidock, David A.

    2008-01-01

    SUMMARY Fatty acid biosynthesis has been viewed as an important biological function of and therapeutic target for Plasmodium falciparum asexual blood stage infection. This apicoplast-resident type II pathway, distinct from the mammalian type I process, includes FabI. Here, we report synthetic chemistry and transfection studies concluding that Plasmodium FabI is not the target of the antimalarial activity of the bacterial FabI inhibitor triclosan. Disruption of fabI in P. falciparum or the rodent parasite P. berghei does not impede blood stage growth. In contrast, mosquito-derived fabI-deficient P. berghei sporozoites are markedly less infective for mice and typically fail to complete liver stage development in vitro. This is characterized by an inability to form intra-hepatic merosomes that normally initiate blood stage infections. These data illuminate key differences between liver and blood stage parasites in their requirements for host versus de novo synthesized fatty acids, and create new prospects for stage-specific antimalarial interventions. PMID:19064257

  12. The fatty acid biosynthesis enzyme FabI plays a key role in the development of liver-stage malarial parasites.

    Science.gov (United States)

    Yu, Min; Kumar, T R Santha; Nkrumah, Louis J; Coppi, Alida; Retzlaff, Silke; Li, Celeste D; Kelly, Brendan J; Moura, Pedro A; Lakshmanan, Viswanathan; Freundlich, Joel S; Valderramos, Juan-Carlos; Vilcheze, Catherine; Siedner, Mark; Tsai, Jennifer H-C; Falkard, Brie; Sidhu, Amar Bir Singh; Purcell, Lisa A; Gratraud, Paul; Kremer, Laurent; Waters, Andrew P; Schiehser, Guy; Jacobus, David P; Janse, Chris J; Ager, Arba; Jacobs, William R; Sacchettini, James C; Heussler, Volker; Sinnis, Photini; Fidock, David A

    2008-12-11

    The fatty acid synthesis type II pathway has received considerable interest as a candidate therapeutic target in Plasmodium falciparum asexual blood-stage infections. This apicoplast-resident pathway, distinct from the mammalian type I process, includes FabI. Here, we report synthetic chemistry and transfection studies concluding that Plasmodium FabI is not the target of the antimalarial activity of triclosan, an inhibitor of bacterial FabI. Disruption of fabI in P. falciparum or the rodent parasite P. berghei does not impede blood-stage growth. In contrast, mosquito-derived, FabI-deficient P. berghei sporozoites are markedly less infective for mice and typically fail to complete liver-stage development in vitro. This defect is characterized by an inability to form intrahepatic merosomes that normally initiate blood-stage infections. These data illuminate key differences between liver- and blood-stage parasites in their requirements for host versus de novo synthesized fatty acids, and create new prospects for stage-specific antimalarial interventions.

  13. Acquired Antibody Responses against Plasmodium vivax Infection Vary with Host Genotype for Duffy Antigen Receptor for Chemokines (DARC)

    Science.gov (United States)

    Maestre, Amanda; Muskus, Carlos; Duque, Victoria; Agudelo, Olga; Liu, Pu; Takagi, Akihide; Ntumngia, Francis B.; Adams, John H.; Sim, Kim Lee; Hoffman, Stephen L.; Corradin, Giampietro; Velez, Ivan D.; Wang, Ruobing

    2010-01-01

    Background Polymorphism of the Duffy Antigen Receptor for Chemokines (DARC) is associated with susceptibility to and the severity of Plasmodium vivax malaria in humans. P. vivax uses DARC to invade erythrocytes. Individuals lacking DARC are ‘resistant’ to P. vivax erythrocytic infection. However, susceptibility to P. vivax in DARC+ individuals is reported to vary between specific DARC genotypes. We hypothesized that the natural acquisition of antibodies to P. vivax blood stages may vary with the host genotype and the level of DARC expression. Furthermore, high parasitemia has been reported to effect the acquisition of immunity against pre-erythrocytic parasites. We investigated the correlation between host DARC genotypes and the frequency and magnitude of antibodies against P. vivax erythrocytic stage antigens. Methodology/Findings We assessed the frequencies and magnitudes of antibody responses against P. vivax and P. falciparum sporozoite and erythrocytic antigens in Colombian donors from malaria-endemic regions. The frequency and level of naturally-acquired antibodies against the P. vivax erythrocytic antigens merozoite surface protein 1 (PvMSP1) and Duffy binding protein (PvDBP) varied with the host DARC genotypes. Donors with one negative allele (FY*B/FY*Bnull and FY*A/FY*Bnull) were more likely to have anti-PvMSP1 and anti-PvDBP antibodies than those with two positive alleles (FY*B/FY*B and FY*A/FY*B). The lower IgG3 and IgG1 components of the total IgG response may account for the decreased responses to P. vivax erythrocytic antigens with FY*A/FY*B and FY*B/FY*B genotypes. No such association was detected with P. falciparum erythrocytic antigens, which does not use DARC for erythrocyte invasion. Conclusion/Significance Individuals with higher DARC expression, which is associated with higher susceptibility to P. vivax infection, exhibited low frequencies and magnitudes of P. vivax blood-stage specific antibody responses. This may indicate that one of the

  14. Acquired antibody responses against Plasmodium vivax infection vary with host genotype for duffy antigen receptor for chemokines (DARC.

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    Amanda Maestre

    2010-07-01

    Full Text Available Polymorphism of the Duffy Antigen Receptor for Chemokines (DARC is associated with susceptibility to and the severity of Plasmodium vivax malaria in humans. P. vivax uses DARC to invade erythrocytes. Individuals lacking DARC are 'resistant' to P. vivax erythrocytic infection. However, susceptibility to P. vivax in DARC+ individuals is reported to vary between specific DARC genotypes. We hypothesized that the natural acquisition of antibodies to P. vivax blood stages may vary with the host genotype and the level of DARC expression. Furthermore, high parasitemia has been reported to effect the acquisition of immunity against pre-erythrocytic parasites. We investigated the correlation between host DARC genotypes and the frequency and magnitude of antibodies against P. vivax erythrocytic stage antigens.We assessed the frequencies and magnitudes of antibody responses against P. vivax and P. falciparum sporozoite and erythrocytic antigens in Colombian donors from malaria-endemic regions. The frequency and level of naturally-acquired antibodies against the P. vivax erythrocytic antigens merozoite surface protein 1 (PvMSP1 and Duffy binding protein (PvDBP varied with the host DARC genotypes. Donors with one negative allele (FY*B/FY*Bnull and FY*A/FY*Bnull were more likely to have anti-PvMSP1 and anti-PvDBP antibodies than those with two positive alleles (FY*B/FY*B and FY*A/FY*B. The lower IgG3 and IgG1 components of the total IgG response may account for the decreased responses to P. vivax erythrocytic antigens with FY*A/FY*B and FY*B/FY*B genotypes. No such association was detected with P. falciparum erythrocytic antigens, which does not use DARC for erythrocyte invasion.Individuals with higher DARC expression, which is associated with higher susceptibility to P. vivax infection, exhibited low frequencies and magnitudes of P. vivax blood-stage specific antibody responses. This may indicate that one of the primary mechanisms by which P. vivax evades

  15. Description, molecular characterisation, diagnostics and life cycle of Plasmodium elongatum (lineage pERIRUB01), the virulent avian malaria parasite.

    Science.gov (United States)

    Palinauskas, Vaidas; Žiegytė, Rita; Iezhova, Tatjana A; Ilgūnas, Mikas; Bernotienė, Rasa; Valkiūnas, Gediminas

    2016-10-01

    Plasmodium elongatum causes severe avian malaria and is distributed worldwide. This parasite is of particular importance due to its ability to develop and cause lethal malaria not only in natural hosts, but also in non-adapted endemic birds such as the brown kiwi and different species of penguins. Information on vectors of this infection is available but is contradictory. PCR-based analysis indicated the possible existence of a cluster of closely related P. elongatum lineages which might differ in their ability to develop in certain mosquitoes and birds. This experimental study provides information about molecular and morphological characterisation of a virulent P. elongatum strain (lineage pERIRUB01) isolated from a naturally infected European robin, Erithacus rubecula. Phylogenetic analysis based on partial cytochrome b gene sequences showed that this parasite lineage is closely related to P. elongatum (lineage pGRW6). Blood stages of both parasite lineages are indistinguishable, indicating that they belong to the same species. Both pathogens develop in experimentally infected canaries, Serinus canaria, causing death of the hosts. In both these lineages, trophozoites and erythrocytic meronts develop in polychromatic erythrocytes and erythroblasts, gametocytes parasitize mature erythrocytes, exoerythrocytic stages develop in cells of the erythrocytic series in bone marrow and are occasionally reported in spleen and liver. Massive infestation of bone marrow cells is the main reason for bird mortality. We report here on syncytium-like remnants of tissue meronts, which slip out of the bone marrow into the peripheral circulation, providing evidence that the syncytia can be a template for PCR amplification. This finding contributes to better understanding positive PCR amplifications in birds when parasitemia is invisible and improved diagnostics of abortive haemosporidian infections. Sporogony of P. elongatum (pERIRUB01) completes the cycle and sporozoites develop in

  16. High prevalence of drug-resistance mutations in Plasmodium falciparum and Plasmodium vivax in southern Ethiopia

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    Löscher Thomas

    2006-07-01

    Full Text Available Abstract Background In Ethiopia, malaria is caused by both Plasmodium falciparum and Plasmodium vivax. Drug resistance of P. falciparum to sulfadoxine-pyrimethamine (SP and chloroquine (CQ is frequent and intense in some areas. Methods In 100 patients with uncomplicated malaria from Dilla, southern Ethiopia, P. falciparum dhfr and dhps mutations as well as P. vivax dhfr polymorphisms associated with resistance to SP and P. falciparum pfcrt and pfmdr1 mutations conferring CQ resistance were assessed. Results P. falciparum and P. vivax were observed in 69% and 31% of the patients, respectively. Pfdhfr triple mutations and pfdhfr/pfdhps quintuple mutations occurred in 87% and 86% of P. falciparum isolates, respectively. Pfcrt T76 was seen in all and pfmdr1 Y86 in 81% of P. falciparum. The P. vivax dhfr core mutations N117 and R58 were present in 94% and 74%, respectively. Conclusion These data point to an extraordinarily high frequency of drug-resistance mutations in both P. falciparum and P. vivax in southern Ethiopia, and strongly support that both SP and CQ are inadequate drugs for this region.

  17. Plasmodium falciparum secretome in erythrocyte and beyond

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    Rani eSoni

    2016-02-01

    Full Text Available Plasmodium falciparum is the causative agent of deadly malaria disease. It is an intracellular eukaryote and completes its multi-stage life cycle spanning the two hosts viz, mosquito and human. In order to habituate within host environment, parasite conform several strategies to evade host immune responses such as surface antigen polymorphism or modulation of host immune system and it is mediated by secretion of proteins from parasite to the host erythrocyte and beyond, collectively known as, malaria secretome. In this review, we will discuss about the deployment of parasitic secretory protein in mechanism implicated for immune evasion, protein trafficking, providing virulence, changing permeability and cyto-adherence of infected erythrocyte. We will be covering the possibilities of developing malaria secretome as a drug/vaccine target. This gathered information will be worthwhile in depicting a well-organized picture for host-pathogen interplay during the malaria infection and may also provide some clues for development of novel anti-malarial therapies.

  18. Frequency of thrombocytopenia in plasmodium vivax malaria

    International Nuclear Information System (INIS)

    Nadeem, A.; Malik, T.M.; Malik, H.S.

    2014-01-01

    Objective: To determine the frequency of thrombocytopenia in Plasmodium vivax (P.vivax) malaria cases at two hospitals. Study Design: Cross-sectional descriptive study. Place and Duration of Study: The study was conducted at the departments of Pathology, Combined Military Hospitals Malir and Sibi, Pakistan from Jul 2011 to Mar 2012. Patients and Methods: A total of 2709 samples were collected from febrile patients for detection of malaria parasite (944 from CMH Malir and 1765 from CMH Sibi). Cases having infection with P. falciparum alone or having mixed infection with P. Vivax and P. falciparum were excluded from the study. Both thick and thin film microscopy and immunochromatographic method (OptiMA L-IT) were used for detection of malarial parasite. Platelet counts were done using automated haematology analyser (Sysmex KX 21) with re-evaluation of low counts with manual methods. Results: Total of 170 patients were found positive for P. vivax malaria (44 from CMH Malir and 126 from CMH Sibi). Platelet counts ranged from 21 - 457 * 10/sub 9/ with a mean of 134 * 10/sub 9/. Ninety five (2.1%) from CMH Malir and 4.2% from CMH Sibi out of 170 patients had thrombocytopenia, and the difference in thrombocytopenia at the two hospitals was insignificant (0.017). Conclusion: Thrombocytopenia in patients with P. vivax infection is equally prevalent in the two hospitals, representing a widely different geographical area and should prompt a more thorough search for malaria parasite. (author)

  19. Proteomics methods applied to malaria: Plasmodium falciparum

    International Nuclear Information System (INIS)

    Cuesta Astroz, Yesid; Segura Latorre, Cesar

    2012-01-01

    Malaria is a parasitic disease that has a high impact on public health in developing countries. The sequencing of the plasmodium falciparum genome and the development of proteomics have enabled a breakthrough in understanding the biology of the parasite. Proteomics have allowed to characterize qualitatively and quantitatively the parasite s expression of proteins and has provided information on protein expression under conditions of stress induced by antimalarial. Given the complexity of their life cycle, this takes place in the vertebrate host and mosquito vector. It has proven difficult to characterize the protein expression during each stage throughout the infection process in order to determine the proteome that mediates several metabolic, physiological and energetic processes. Two dimensional electrophoresis, liquid chromatography and mass spectrometry have been useful to assess the effects of antimalarial on parasite protein expression and to characterize the proteomic profile of different p. falciparum stages and organelles. The purpose of this review is to present state of the art tools and advances in proteomics applied to the study of malaria, and to present different experimental strategies used to study the parasite's proteome in order to show the advantages and disadvantages of each one.

  20. Phenomics, Genomics and Genetics in Plasmodium vinckei

    KAUST Repository

    Ramaprasad, Abhinay

    2017-11-01

    Rodent malaria parasites (RMPs) serve as tractable models for experimental genetics, and as valuable tools to study malaria parasite biology and host-parasitevector interactions. Plasmodium vinckei, one of four RMPs adapted to laboratory mice, is the most geographically widespread species and displays considerable phenotypic and genotypic diversity amongst its subspecies and strains. The phenotypes and genotypes of P. vinckei isolates have been relatively less characterized compared to other RMPs, hampering its use as an experimental model for malaria. Here, we have studied the phenotypes and sequenced the genomes and transcriptomes of ten P. vinckei isolates including representatives of all five subspecies, all of which were collected from wild thicket rats (Thamnomys rutilans) in sub-Saharan Central Africa between the late 1940s and mid 1960s. We have generated a comprehensive resource for P. vinckei comprising of five high-quality reference genomes, growth profiles and genotypes of P. vinckei isolates, and expression profiles of genes across the intra-erythrocytic developmental stages of the parasite. We observe significant phenotypic and genotypic diversity among P. vinckei isolates, making them particularly suitable for classical genetics and genomics-driven studies on malaria parasite biology. As part of a proof of concept study, we have shown that experimental genetic crosses can be performed between P. vinckei parasites to potentially identify genotype-phenotype relationships. We have also shown that they are amenable to genetic manipulation in the laboratory.

  1. Dibenzylideneacetone analogues as novel Plasmodium falciparum inhibitors.

    Science.gov (United States)

    Aher, Rahul Balasaheb; Wanare, Gajanan; Kawathekar, Neha; Kumar, Ravi Ranjan; Kaushik, Naveen Kumar; Sahal, Dinkar; Chauhan, Virander Singh

    2011-05-15

    A series of dibenzylideneacetones (A1-A12) and some of their pyrazolines (B1-B4) were synthesized and evaluated in vitro for blood stage antiplasmodial properties in Plasmodium falciparum culture using SYBR-green-I fluorescence assay. The compound (1E, 4E)-1,5-bis(3,4-dimethoxyphenyl)penta-1,4-dien-3-one (A9) was found to be the most active with IC(50) of 1.97 μM against chloroquine-sensitive strain (3D7) and 1.69 μM against chloroquine-resistant field isolate (RKL9). The MTT based cytotoxicity assay on HeLa cell line has confirmed that A9 is selective in its action against malaria parasite (with a therapeutic index of 166). Our results revealed that these compounds exhibited promising antiplasmodial activities which can be further explored as potential leads for the development of cheaper, safe, effective and potent drugs against chloroquine-resistant malarial parasites. Copyright © 2011. Published by Elsevier Ltd.

  2. Patterns of Plasmodium vivax and Plasmodium falciparum malaria underscore importance of data collection from private health care facilities in India.

    Science.gov (United States)

    Gupta, Sangeeta; Gunter, James T; Novak, Robert J; Regens, James L

    2009-10-12

    This study describes patterns of falciparum and vivax malaria in a private comprehensive-care, multi-specialty hospital in New Delhi from July 2006 to July 2008. Malarial morbidity by Plasmodium species (Plasmodium falciparum, Plasmodium vivax, or Plasmodium sp.) was confirmed using microscopy and antigen tests. The influence of seasonal factors and selected patient demographics on morbidity was evaluated. The proportions of malaria cases caused by P. falciparum at the private facility were compared to data from India's National Vector Borne Disease Control Programme (NVBDCP) during the same period for the Delhi region. In New Delhi, P. faciparum was the dominant cause of cases requiring treatment in the private hospital during the period examined. The national data reported a smaller proportion of malaria cases caused by P. falciparum in the national capital region than was observed in a private facility within the region. Plasmodium vivax also caused a large proportion of the cases presenting clinically at the private hospital during the summer and monsoon seasons. The proportion of P. falciparum malaria cases tends to be greatest during the post-monsoon season while the proportion of P. vivax malaria cases tends to be greatest in the monsoon season. Private hospital data demonstrate an under-reporting of malaria case incidences in the data from India's national surveillance programme during the same period for the national capital region.

  3. Plasmodium knowlesi: from severe zoonosis to animal model.

    Science.gov (United States)

    Cox-Singh, Janet; Culleton, Richard

    2015-06-01

    Plasmodium knowlesi malaria is a newly described zoonosis in Southeast Asia. Similarly to Plasmodium falciparum, P. knowlesi can reach high parasitaemia in the human host and both species cause severe and fatal illness. Interpretation of host-parasite interactions in studies of P. knowlesi malaria adds a counterpoint to studies on P. falciparum. However, there is no model system for testing the resulting hypotheses on malaria pathophysiology or for developing new interventions. Plasmodium knowlesi is amenable to genetic manipulation in vitro and several nonhuman primate species are susceptible to experimental infection. Here, we make a case for drawing on P. knowlesi as both a human pathogen and an experimental model to lift the roadblock between malaria research and its translation into human health benefits. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. From malaria parasite point of view – Plasmodium falciparum evolution

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    Agata Zerka

    2015-12-01

    Full Text Available Malaria is caused by infection with protozoan parasites belonging to the genus Plasmodium, which have arguably exerted the greatest selection pressure on humans in the history of our species. Besides humans, different Plasmodium parasites infect a wide range of animal hosts, from marine invertebrates to primates. On the other hand, individual Plasmodium species show high host specificity. The extraordinary evolution of Plasmodium probably began when a free-living red algae turned parasitic, and culminated with its ability to thrive inside a human red blood cell. Studies on the African apes generated new data on the evolution of malaria parasites in general and the deadliest human-specific species, Plasmodium falciparum, in particular. Initially, it was hypothesized that P. falciparum descended from the chimpanzee malaria parasite P. reichenowi, after the human and the chimp lineage diverged about 6 million years ago. However, a recently identified new species infecting gorillas, unexpectedly showed similarity to P. falciparum and was therefore named P. praefalciparum. That finding spurred an alternative hypothesis, which proposes that P. falciparum descended from its gorilla rather than chimp counterpart. In addition, the gorilla-to-human host shift may have occurred more recently (about 10 thousand years ago than the theoretical P. falciparum-P. reichenowi split. One of the key aims of the studies on Plasmodium evolution is to elucidate the mechanisms that allow the incessant host shifting and retaining the host specificity, especially in the case of human-specific species. Thorough understanding of these phenomena will be necessary to design effective malaria treatment and prevention strategies.

  5. Molecular identification of the chitinase genes in Plasmodium relictum.

    Science.gov (United States)

    Garcia-Longoria, Luz; Hellgren, Olof; Bensch, Staffan

    2014-06-18

    Malaria parasites need to synthesize chitinase in order to go through the peritrophic membrane, which is created around the mosquito midgut, to complete its life cycle. In mammalian malaria species, the chitinase gene comprises either a large or a short copy. In the avian malaria parasites Plasmodium gallinaceum both copies are present, suggesting that a gene duplication in the ancestor to these extant species preceded the loss of either the long or the short copy in Plasmodium parasites of mammals. Plasmodium gallinaceum is not the most widespread and harmful parasite of birds. This study is the first to search for and identify the chitinase gene in one of the most prevalent avian malaria parasites, Plasmodium relictum. Both copies of P. gallinaceum chitinase were used as reference sequences for primer design. Different sequences of Plasmodium spp. were used to build the phylogenetic tree of chitinase gene. The gene encoding for chitinase was identified in isolates of two mitochondrial lineages of P. relictum (SGS1 and GRW4). The chitinase found in these two lineages consists both of the long (PrCHT1) and the short (PrCHT2) copy. The genetic differences found in the long copy of the chitinase gene between SGS1 and GRW4 were higher than the difference observed for the cytochrome b gene. The identification of both copies in P. relictum sheds light on the phylogenetic relationship of the chitinase gene in the genus Plasmodium. Due to its high variability, the chitinase gene could be used to study the genetic population structure in isolates from different host species and geographic regions.

  6. Comparative Genomics and Systems Biology of Malaria Parasites Plasmodium

    Science.gov (United States)

    Cai, Hong; Zhou, Zhan; Gu, Jianying; Wang, Yufeng

    2013-01-01

    Malaria is a serious infectious disease that causes over one million deaths yearly. It is caused by a group of protozoan parasites in the genus Plasmodium. No effective vaccine is currently available and the elevated levels of resistance to drugs in use underscore the pressing need for novel antimalarial targets. In this review, we survey omics centered developments in Plasmodium biology, which have set the stage for a quantum leap in our understanding of the fundamental processes of the parasite life cycle and mechanisms of drug resistance and immune evasion. PMID:24298232

  7. Therapeutic principles of primaquine against relapse of Plasmodium vivax malaria

    Science.gov (United States)

    Baird, J. K.

    2018-03-01

    Plasmodium vivax causes tens of millions of clinical attacks annually all across the malarious globe. Unlike the other major cause of human malaria, Plasmodium falciparum, P. vivax places dormant stages called hypnozoites into the human liver that later awaken and provoke multiple clinical attacks in the weeks, months, and few years following the infectious anopheline mosquito bite. The only available treatment to prevent those recurrent attacks is primaquine (hypnozoitocide), and it must be administered with the drugs applied to end the acute attack (blood schizontocides). This paper reviews the therapeutic principles of applying primaquine to achieve radical cure of acute vivax malaria.

  8. Circumsporozoite Protein-Specific Kd-Restricted CD8+ T Cells Mediate Protective Antimalaria Immunity in Sporozoite-Immunized MHC-I-Kd Transgenic Mice

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    Jing Huang

    2014-01-01

    Full Text Available Although the roles of CD8+ T cells and a major preerythrocytic antigen, the circumsporozoite (CS protein, in contributing protective antimalaria immunity induced by radiation-attenuated sporozoites, have been shown by a number of studies, the extent to which these players contribute to antimalaria immunity is still unknown. To address this question, we have generated C57BL/6 (B6 transgenic (Tg mice, expressing Kd molecules under the MHC-I promoter, called MHC-I-Kd-Tg mice. In this study, we first determined that a single immunizing dose of IrPySpz induced a significant level of antimalaria protective immunity in MHC-I-Kd-Tg mice but not in B6 mice. Then, by depleting various T-cell subsets in vivo, we determined that CD8+ T cells are the main mediator of the protective immunity induced by IrPySpz. Furthermore, when we immunized (MHC-I-Kd-Tg × CS-Tg F1 mice with IrPySpz after crossing MHC-I-Kd-Tg mice with PyCS-transgenic mice (CS-Tg, which are unable to mount PyCS-specific immunity, we found that IrPySpz immunization failed to induce protective antimalaria immunity in (MHC-I-Kd-Tg × CS-Tg F1 mice, thus indicating the absence of PyCS antigen-dependent immunity in these mice. These results indicate that protective antimalaria immunity induced by IrPySpz in MHC-I-Kd-Tg mice is mediated by CS protein-specific, Kd-restricted CD8+ T cells.

  9. The dynamics of natural Plasmodium falciparum infections.

    Directory of Open Access Journals (Sweden)

    Ingrid Felger

    Full Text Available BACKGROUND: Natural immunity to Plasmodium falciparum has been widely studied, but its effects on parasite dynamics are poorly understood. Acquisition and clearance rates of untreated infections are key elements of the dynamics of malaria, but estimating these parameters is challenging because of frequent super-infection and imperfect detectability of parasites. Consequently, information on effects of host immune status or age on infection dynamics is fragmentary. METHODS: An age-stratified cohort of 347 individuals from Northern Ghana was sampled six times at 2 month intervals. High-throughput capillary electrophoresis was used to genotype the msp-2 locus of all P. falciparum infections detected by PCR. Force of infection (FOI and duration were estimated for each age group using an immigration-death model that allows for imperfect detection of circulating parasites. RESULTS: Allowing for imperfect detection substantially increased estimates of FOI and duration. Effects of naturally acquired immunity on the FOI and duration would be reflected in age dependence in these indices, but in our cohort data FOI tended to increase with age in children. Persistence of individual parasite clones was characteristic of all age-groups. Duration peaked in 5-9 year old children (average duration 319 days, 95% confidence interval 318;320. CONCLUSIONS: The main age-dependence is on parasite densities, with only small age-variations in the FOI and persistence of infections. This supports the hypothesis that acquired immunity controls transmission mainly by limiting blood-stage parasite densities rather than changing rates of acquisition or clearance of infections.

  10. The persistence and oscillations of submicroscopic Plasmodium falciparum and Plasmodium vivax infections over time in Vietnam: an open cohort study.

    Science.gov (United States)

    Nguyen, Thuy-Nhien; von Seidlein, Lorenz; Nguyen, Tuong-Vy; Truong, Phuc-Nhi; Hung, Son Do; Pham, Huong-Thu; Nguyen, Tam-Uyen; Le, Thanh Dong; Dao, Van Hue; Mukaka, Mavuto; Day, Nicholas Pj; White, Nicholas J; Dondorp, Arjen M; Thwaites, Guy E; Hien, Tran Tinh

    2018-05-01

    A substantial proportion of Plasmodium species infections are asymptomatic with densities too low to be detectable with standard diagnostic techniques. The importance of such asymptomatic plasmodium infections in malaria transmission is probably related to their duration and density. To explore the duration of asymptomatic plasmodium infections and changes in parasite densities over time, a cohort of participants who were infected with Plasmodium parasites was observed over a 2-year follow-up period. In this open cohort study, inhabitants of four villages in Vietnam were invited to participate in baseline and subsequent 3-monthly surveys up to 24 months, which included the collection of venous blood samples. Samples were batch-screened using ultra-sensitive (u)PCR (lower limit of detection of 22 parasites per mL). Participants found to be infected by uPCR during any of these surveys were invited to join a prospective cohort and provide monthly blood samples. We estimated the persistence of Plasmodium falciparum and Plasmodium vivax infections and changes in parasite densities over a study period of 24 months. Between Dec 1, 2013, and Jan 8, 2016, 356 villagers participated in between one and 22 surveys. These study participants underwent 4248 uPCR evaluations (11·9 tests per participant). 1874 (32%) of 4248 uPCR tests indicated a plasmodium infection; 679 (36%) of 1874 tests were P falciparum monoinfections, 507 (27%) were P vivax monoinfections, 463 (25%) were co-infections with P falciparum and P vivax, and 225 (12%) were indeterminate species of Plasmodium. The median duration of P falciparum infection was 2 months (IQR 1-3); after accounting for censoring, participants had a 20% chance of having parasitaemia for 4 months or longer. The median duration of P vivax infection was 6 months (3-9), and participants had a 59% chance of having parasitaemia for 4 months or longer. The parasite densities of persistent infections oscillated; following ultralow

  11. Modelling the incidence of Plasmodium vivax and Plasmodium falciparum malaria in Afghanistan 2006-2009.

    Science.gov (United States)

    Alegana, Victor A; Wright, Jim A; Nahzat, Sami M; Butt, Waqar; Sediqi, Amad W; Habib, Naeem; Snow, Robert W; Atkinson, Peter M; Noor, Abdisalan M

    2014-01-01

    Identifying areas that support high malaria risks and where populations lack access to health care is central to reducing the burden in Afghanistan. This study investigated the incidence of Plasmodium vivax and Plasmodium falciparum using routine data to help focus malaria interventions. To estimate incidence, the study modelled utilisation of the public health sector using fever treatment data from the 2012 national Malaria Indicator Survey. A probabilistic measure of attendance was applied to population density metrics to define the proportion of the population within catchment of a public health facility. Malaria data were used in a Bayesian spatio-temporal conditional-autoregressive model with ecological or environmental covariates, to examine the spatial and temporal variation of incidence. From the analysis of healthcare utilisation, over 80% of the population was within 2 hours' travel of the nearest public health facility, while 64.4% were within 30 minutes' travel. The mean incidence of P. vivax in 2009 was 5.4 (95% Crl 3.2-9.2) cases per 1000 population compared to 1.2 (95% Crl 0.4-2.9) cases per 1000 population for P. falciparum. P. vivax peaked in August while P. falciparum peaked in November. 32% of the estimated 30.5 million people lived in regions where annual incidence was at least 1 case per 1,000 population of P. vivax; 23.7% of the population lived in areas where annual P. falciparum case incidence was at least 1 per 1000. This study showed how routine data can be combined with household survey data to model malaria incidence. The incidence of both P. vivax and P. falciparum in Afghanistan remain low but the co-distribution of both parasites and the lag in their peak season provides challenges to malaria control in Afghanistan. Future improved case definition to determine levels of imported risks may be useful for the elimination ambitions in Afghanistan.

  12. Modelling the Incidence of Plasmodium vivax and Plasmodium falciparum Malaria in Afghanistan 2006–2009

    Science.gov (United States)

    Alegana, Victor A.; Wright, Jim A.; Nahzat, Sami M.; Butt, Waqar; Sediqi, Amad W.; Habib, Naeem; Snow, Robert W.; Atkinson, Peter M.; Noor, Abdisalan M.

    2014-01-01

    Background Identifying areas that support high malaria risks and where populations lack access to health care is central to reducing the burden in Afghanistan. This study investigated the incidence of Plasmodium vivax and Plasmodium falciparum using routine data to help focus malaria interventions. Methods To estimate incidence, the study modelled utilisation of the public health sector using fever treatment data from the 2012 national Malaria Indicator Survey. A probabilistic measure of attendance was applied to population density metrics to define the proportion of the population within catchment of a public health facility. Malaria data were used in a Bayesian spatio-temporal conditional-autoregressive model with ecological or environmental covariates, to examine the spatial and temporal variation of incidence. Findings From the analysis of healthcare utilisation, over 80% of the population was within 2 hours’ travel of the nearest public health facility, while 64.4% were within 30 minutes’ travel. The mean incidence of P. vivax in 2009 was 5.4 (95% Crl 3.2–9.2) cases per 1000 population compared to 1.2 (95% Crl 0.4–2.9) cases per 1000 population for P. falciparum. P. vivax peaked in August while P. falciparum peaked in November. 32% of the estimated 30.5 million people lived in regions where annual incidence was at least 1 case per 1,000 population of P. vivax; 23.7% of the population lived in areas where annual P. falciparum case incidence was at least 1 per 1000. Conclusion This study showed how routine data can be combined with household survey data to model malaria incidence. The incidence of both P. vivax and P. falciparum in Afghanistan remain low but the co-distribution of both parasites and the lag in their peak season provides challenges to malaria control in Afghanistan. Future improved case definition to determine levels of imported risks may be useful for the elimination ambitions in Afghanistan. PMID:25033452

  13. Drug resistance associated genetic polymorphisms in Plasmodium falciparum and Plasmodium vivax collected in Honduras, Central America.

    Science.gov (United States)

    Jovel, Irina T; Mejía, Rosa E; Banegas, Engels; Piedade, Rita; Alger, Jackeline; Fontecha, Gustavo; Ferreira, Pedro E; Veiga, Maria I; Enamorado, Irma G; Bjorkman, Anders; Ursing, Johan

    2011-12-19

    In Honduras, chloroquine and primaquine are recommended and still appear to be effective for treatment of Plasmodium falciparum and Plasmodium vivax malaria. The aim of this study was to determine the proportion of resistance associated genetic polymorphisms in P. falciparum and P. vivax collected in Honduras. Blood samples were collected from patients seeking medical attention at the Hospital Escuela in Tegucigalpa from 2004 to 2006 as well as three regional hospitals, two health centres and one regional laboratory during 2009. Single nucleotide polymorphisms in P. falciparum chloroquine resistance transporter (pfcrt), multidrug resistance 1 (pfmdr1), dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) genes and in P. vivax multidrug resistance 1 (pvmdr1) and dihydrofolate reductase (pvdhfr) genes were detected using PCR based methods. Thirty seven P. falciparum and 64 P. vivax samples were collected. All P. falciparum infections acquired in Honduras carried pfcrt, pfmdr1, pfdhps and pfdhfr alleles associated with chloroquine, amodiaquine and sulphadoxine-pyrimethamine sensitivity only. One patient with parasites acquired on a Pacific Island had pfcrt 76 T and pfmdr1 86Y alleles. That patient and a patient infected in West Africa had pfdhfr 51I, 59 R and 108 N alleles. Pvmdr1 976 F was found in 7/37 and two copies of pvmdr1 were found in 1/37 samples. Pvdhfr 57 L + 58 R was observed in 2/57 samples. The results indicate that P. falciparum from Honduras remain sensitive to chloroquine and sulphadoxine-pyrimethamine. This suggests that chloroquine and sulphadoxine-pyrimethamine should be efficacious for treatment of uncomplicated P. falciparum malaria, supporting current national treatment guidelines. However, genetic polymorphisms associated with chloroquine and sulphadoxine-pyrimethamine tolerance were detected in local P. vivax and imported P. falciparum infections. Continuous monitoring of the prevalence of drug resistant/tolerant P

  14. Mechanisms of Plasmodium-Enhanced Attraction of Mosquito Vectors

    NARCIS (Netherlands)

    Busula, A.O.; Verhulst, N.O.; Bousema, J.T.; Takken, W.; Boer, J.G. de

    2017-01-01

    Evidence is accumulating that Plasmodium-infected vertebrates are more attractive to mosquitoes than noninfected hosts, particularly when high levels of gametocytes are present. Changes in host odour have been suggested as a likely target for parasite manipulation because olfactory cues are crucial

  15. A comparison of rapid diagnostic testing (by plasmodium lactate ...

    African Journals Online (AJOL)

    Background: The World Health Organization (WHO) considers early and rapid diagnosis as one of the strategies to control malaria. This study compared the performance of Quantitative Buffy Coat (QBC) test and the Plasmodium lactate dehydrogenase (pLDH) rapid diagnostic test (RDT) with microscopy as the gold ...

  16. Carriage of sub-microscopic sexual and asexual Plasmodium ...

    African Journals Online (AJOL)

    SUMMARY. Background: We investigated the prevalence of sub-microscopic Plasmodium falciparum infections and gameto- cyte carriage in asymptomatic individuals in Navrongo in northern Ghana, an area of seasonal malaria transmission. Design: A cross sectional study of 209 randomly selected participants of all ...

  17. Interleukin-10 regulates hepcidin in Plasmodium falciparum malaria

    KAUST Repository

    Huang, Honglei; Lamikanra, Abigail A.; Alkaitis, Matthew S.; Thé zé nas, Marie L.; Ramaprasad, Abhinay; Moussa, Ehab; Roberts, David J.; Casals-Pascual, Climent

    2014-01-01

    . falciparum malaria. Methods: We have measured secretion of hepcidin by primary macrophages and the hepatoma cell line HepG2 stimulated with IL-10, IL-6 and Plasmodium falciparum-infected erythrocytes. Findings: We have observed that IL-10 and IL-6 production

  18. Variation of nitric oxide levels in imported Plasmodium falciparum ...

    African Journals Online (AJOL)

    SERVER

    2008-03-18

    Mar 18, 2008 ... ISSN 1684–5315 © 2008 Academic Journals. Full Length Research Paper. Variation of nitric oxide levels in imported Plasmodium falciparum malaria episodes. De Sousa, Karina*, Silva, Marcelo S. and Tavira, Luís T. Instituto de Higiene e Medicina Tropical, Centro de Malária e outras Doenças Tropicais, ...

  19. Studies On the Incidence of Asymptomatic Plasmodium Infection ...

    African Journals Online (AJOL)

    The incidence of asymptomatic Plasmodium falciparum infection among orphans between age groups, gender and blood groups was investigated. Standard microscopic methods were used to screen for malaria parasites in the blood specimens obtained from eighty-five (85) subjects in three orphanages in Kaduna and ...

  20. Genomics and epigenetics of sexual commitment in Plasmodium.

    Science.gov (United States)

    Bechtsi, D P; Waters, A P

    2017-06-01

    Malaria is the disease caused by the apicomplexan parasites belonging to the genus Plasmodium. Expanding our arsenal to include transmission-blocking agents in our fight against malaria is becoming increasingly important. Such an implementation requires detailed understanding of the biology of the Plasmodium life cycle stages that are transmissible. Plasmodium gametocytes are the only parasite stage that can be transmitted to the mosquito vector and are the product of sexual development in a small percentage of parasites that continually proliferate in host blood. The critical decision made by asexual erythrocytic stages to cease further proliferation and differentiate into gametocytes, as well as the first steps they take into maturity, have long remained unknown. Recent studies have contributed to a breakthrough in our understanding of this branch point in development. In this review, we will discuss the findings that have allowed us to make this major leap forward in our knowledge of sexual commitment in Plasmodium. We will further propose a model for the mechanism triggering the switch to sexual development, constructed around the proteins currently known to regulate this process. Further insight into sexual commitment and gametocyte development will help identify targets for the development of transmission-blocking malaria therapies. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  1. Positive blood culture with Plasmodium falciparum : Case report

    NARCIS (Netherlands)

    De Vries, Jutte J. C.; Van Assen, Sander; Mulder, André B.; Kampinga, Greetje A.

    2007-01-01

    An adult traveler presented with fever and malaise after returning from Sierra Leone. Young trophozoites of Plasmodium falciparum were seen in a blood smear, with parasitemia being 10%. Moreover, blood cultures drawn on admission signaled as "positive" after 1 day of incubation, but no bacteria were

  2. Origin of the human malaria parasite Plasmodium falciparum in gorillas.

    Science.gov (United States)

    Liu, Weimin; Li, Yingying; Learn, Gerald H; Rudicell, Rebecca S; Robertson, Joel D; Keele, Brandon F; Ndjango, Jean-Bosco N; Sanz, Crickette M; Morgan, David B; Locatelli, Sabrina; Gonder, Mary K; Kranzusch, Philip J; Walsh, Peter D; Delaporte, Eric; Mpoudi-Ngole, Eitel; Georgiev, Alexander V; Muller, Martin N; Shaw, George M; Peeters, Martine; Sharp, Paul M; Rayner, Julian C; Hahn, Beatrice H

    2010-09-23

    Plasmodium falciparum is the most prevalent and lethal of the malaria parasites infecting humans, yet the origin and evolutionary history of this important pathogen remain controversial. Here we develop a single-genome amplification strategy to identify and characterize Plasmodium spp. DNA sequences in faecal samples from wild-living apes. Among nearly 3,000 specimens collected from field sites throughout central Africa, we found Plasmodium infection in chimpanzees (Pan troglodytes) and western gorillas (Gorilla gorilla), but not in eastern gorillas (Gorilla beringei) or bonobos (Pan paniscus). Ape plasmodial infections were highly prevalent, widely distributed and almost always made up of mixed parasite species. Analysis of more than 1,100 mitochondrial, apicoplast and nuclear gene sequences from chimpanzees and gorillas revealed that 99% grouped within one of six host-specific lineages representing distinct Plasmodium species within the subgenus Laverania. One of these from western gorillas comprised parasites that were nearly identical to P. falciparum. In phylogenetic analyses of full-length mitochondrial sequences, human P. falciparum formed a monophyletic lineage within the gorilla parasite radiation. These findings indicate that P. falciparum is of gorilla origin and not of chimpanzee, bonobo or ancient human origin.

  3. Plasmodium falciparum transcriptome analysis reveals pregnancy malaria associated gene expression

    DEFF Research Database (Denmark)

    Tuikue Ndam, Nicaise; Bischoff, Emmanuel; Proux, Caroline

    2008-01-01

    BACKGROUND: Pregnancy-associated malaria (PAM) causing maternal anemia and low birth weight is among the multiple manifestations of Plasmodium falciparum malaria. Infected erythrocytes (iEs) can acquire various adhesive properties that mediate the clinical severity of malaria. Recent advances...

  4. Unusual Transmission of Plasmodium falciparum, Bordeaux, France, 2009

    Science.gov (United States)

    Vareil, Marc-Olivier; Tandonnet, Olivier; Chemoul, Audrey; Bogreau, Hervé; Saint-Léger, Mélanie; Micheau, Maguy; Millet, Pascal; Koeck, Jean-Louis; Boyer, Alexandre; Rogier, Christophe

    2011-01-01

    Plasmodium falciparum malaria is usually transmitted by mosquitoes. We report 2 cases in France transmitted by other modes: occupational blood exposure and blood transfusion. Even where malaria is not endemic, it should be considered as a cause of unexplained acute fever. PMID:21291597

  5. Inactivation of Plasmodium falciparum in whole body by riboflavin ...

    African Journals Online (AJOL)

    Background Malaria parasites are frequently trans- mitted by unscreened blood transfusions in Africa. Pathogen reduction methods in whole blood would thus greatly improve blood safety. We aimed to determine the efficacy of riboflavin plus irradiation for treatment of whole blood infected with Plasmodium falciparum.

  6. Exploring Anopheles gut bacteria for Plasmodium blocking activity

    Science.gov (United States)

    Bahia, Ana C; Dong, Yuemei; Blumberg, Benjamin J; Mlambo, Godfree; Tripathi, Abhai; BenMarzouk-Hidalgo, Omar J; Chandra, Ramesh; Dimopoulos, George

    2014-01-01

    SUMMARY Malaria parasite transmission requires the successful development of Plasmodium gametocytes into flagellated microgametes upon mosquito blood ingestion, and the subsequent fertilization of microgametes and macrogametes for the development of motile zygotes, called ookinetes, which invade and transverse the Anopheles vector mosquito midgut at around 18-36 h after blood ingestion. Within the mosquito midgut, the malaria parasite has to withstand the mosquito's innate immune response and the detrimental effect of its commensal bacterial flora. We have assessed the midgut colonization capacity of 5 gut bacterial isolates from field-derived, and 2 from laboratory colony, mosquitoes and their effect on Plasmodium development in vivo and in vitro, along with their impact on mosquito survival. Some bacterial isolates activated the mosquito's immune system, affected the mosquito's life span, and were capable of blocking Plasmodium development. We have also shown that the ability of these bacteria to inhibit the parasites is likely to involve different mechanisms and factors. A Serratia marcescens isolate was particularly efficient in colonizing the mosquitoes’ gut, compromising mosquito survival, and inhibiting both sexual- and asexual-stage Plasmodium through secreted factors, thereby rendering it a potential candidate for the development of a malaria transmission intervention strategy. PMID:24428613

  7. Dhfr and dhps mutations in Plasmodium falciparum isolates in ...

    African Journals Online (AJOL)

    Sulfadoxine-pyrimethamine (SP), the current first line antimalarial drug in Tanzania, is compromised by evolution and spread of mutations in the parasite's dhfr and dhps genes. In the present study we established the baseline frequencies of Plasmodium falciparum dihydrofolate reductase (pfdhfr) and dihydropteroate ...

  8. Population genomics diversity of Plasmodium falciparum in malaria ...

    African Journals Online (AJOL)

    Background: Plasmodium falciparum, the most dangerous malaria parasite species to ... tigen for subunit malaria vaccine.10 It comprises highly ... were also prepared for Giemsa staining as described by ... parasites with different alleles at a given locus and ranges ..... surface protein 1, immune evasion and vaccines against.

  9. Genotyping Plasmodium vivax isolates from the 2011 outbreak in Greece

    DEFF Research Database (Denmark)

    Spanakos, Gregory; Alifrangis, Michael; Schousboe, Mette L

    2013-01-01

    Plasmodium vivax malaria was common in Greece until the 1950s with epidemics involving thousands of cases every year. Greece was declared free of malaria by the World Health Organization in 1974. From 1974 to 2010, an average of 39 cases per year were reported, which were mainly imported. However...... during 2011 is described, to elucidate the possible origin and spread of the disease....

  10. Different apoptotic responses to Plasmodium chabaudi malaria in ...

    African Journals Online (AJOL)

    hope&shola

    2010-11-08

    Nov 8, 2010 ... The purpose of this study is to determine whether the apoptotic responses to Plasmodium chabaudi malaria in spleen and liver via mRNA expression of three genes involved in apoptosis (Bax, Bcl-2 and. Caspase-3) are similar or not and to detect if these genes could be a good marker for apoptosis due to.

  11. High prevalence of asymptomatic plasmodium infection in a suburb ...

    African Journals Online (AJOL)

    Background: Malaria is endemic in many parts of the world. Various strategies have been planned to control malaria from time to time in many places. Whatever may be the strategy the prevalence of symptomatic and asymptomatic plasmodium parasitaemics has been of prime importance as useful parameter for its control.

  12. Fine-scale genetic characterization of Plasmodium falciparum

    Indian Academy of Sciences (India)

    We have initiated such a study and presented herewith the results from the in silico understanding of a seventh chromosomal region of the malarial parasite Plasmodium falciparum encompassing the antigenic var genes (coding pfemp1) and the drug-resistant gene pfcrt located at a specified region of the chromosome 7.

  13. Submicroscopic Plasmodium falciparum infections in pregnancy in Ghana

    NARCIS (Netherlands)

    Mockenhaupt, F. P.; Rong, B.; Till, H.; Eggelte, T. A.; Beck, S.; Gyasi-Sarpong, C.; Thompson, W. N.; Bienzle, U.

    2000-01-01

    Malarial parasitaemia below the threshold of microscopy but detectable by polymerase chain reaction (PCR) assays is common in endemic regions. This study was conducted to examine prevalence, predictors, and effects of submicroscopic Plasmodium falciparum infections in pregnancy. In a cross-sectional

  14. High prevalence of Plasmodium falciparum malaria among Human ...

    African Journals Online (AJOL)

    Malaria and Human Immunodeficiency Virus (HIV) infections are major public health problems in Sub-Saharan Africa. Their overlapping geographical distribution and co-existence often result into high morbidity and mortality. This study was designed to establish the prevalence of Plasmodium falciparum malaria among HIV ...

  15. HLA-A alleles differentially associate with severity to Plasmodium ...

    African Journals Online (AJOL)

    Human Leukocyte Antigen (HLA), particularly HLA-B and class II alleles have been differentially associated with disease outcomes in different populations following infection with the malaria Plasmodium falciparum. However, the effect of HLA-A on malaria infection and/or disease is not fully understood. Recently, HLA-A ...

  16. Plasmodium falciparum multiplicity correlates with anaemia in symptomatic malaria

    NARCIS (Netherlands)

    Mockenhaupt, Frank P.; Ehrhardt, Stephan; Eggelte, Teunis A.; Markert, Miriam; Anemana, Sylvester; Otchwemah, Rowland; Bienzle, Ulrich

    2003-01-01

    In 366 Ghanaian children with symptomatic Plasmodium falciparum malaria, low haemoglobin levels and severe anaemia were associated with a high multiplicity of infection (MOI) and with distinct merozoite surface protein alleles. High MOI not only reflects premunition but may also contribute to

  17. Small Molecule Screen for Candidate Antimalarials Targeting Plasmodium Kinesin-5*

    Science.gov (United States)

    Liu, Liqiong; Richard, Jessica; Kim, Sunyoung; Wojcik, Edward J.

    2014-01-01

    Plasmodium falciparum and vivax are responsible for the majority of malaria infections worldwide, resulting in over a million deaths annually. Malaria parasites now show measured resistance to all currently utilized drugs. Novel antimalarial drugs are urgently needed. The Plasmodium Kinesin-5 mechanoenzyme is a suitable “next generation” target. Discovered via small molecule screen experiments, the human Kinesin-5 has multiple allosteric sites that are “druggable.” One site in particular, unique in its sequence divergence across all homologs in the superfamily and even within the same family, exhibits exquisite drug specificity. We propose that Plasmodium Kinesin-5 shares this allosteric site and likewise can be targeted to uncover inhibitors with high specificity. To test this idea, we performed a screen for inhibitors selective for Plasmodium Kinesin-5 ATPase activity in parallel with human Kinesin-5. Our screen of nearly 2000 compounds successfully identified compounds that selectively inhibit both P. vivax and falciparum Kinesin-5 motor domains but, as anticipated, do not impact human Kinesin-5 activity. Of note is a candidate drug that did not biochemically compete with the ATP substrate for the conserved active site or disrupt the microtubule-binding site. Together, our experiments identified MMV666693 as a selective allosteric inhibitor of Plasmodium Kinesin-5; this is the first identified protein target for the Medicines of Malaria Venture validated collection of parasite proliferation inhibitors. This work demonstrates that chemical screens against human kinesins are adaptable to homologs in disease organisms and, as such, extendable to strategies to combat infectious disease. PMID:24737313

  18. Anopheles moucheti and Anopheles vinckei are candidate vectors of ape Plasmodium parasites, including Plasmodium praefalciparum in Gabon.

    Directory of Open Access Journals (Sweden)

    Christophe Paupy

    Full Text Available During the last four years, knowledge about the diversity of Plasmodium species in African great apes has considerably increased. Several new species were described in chimpanzees and gorillas, and some species that were previously considered as strictly of human interest were found to be infecting African apes. The description in gorillas of P. praefalciparum, the closest relative of P. falciparum which is the main malignant agent of human malaria, definitively changed the way we understand the evolution and origin of P. falciparum. This parasite is now considered to have appeared recently, following a cross-species transfer from gorillas to humans. However, the Plasmodium vector mosquito species that have served as bridge between these two host species remain unknown. In order to identify the vectors that ensure ape Plasmodium transmission and evaluate the risk of transfer of these parasites to humans, we carried out a field study in Gabon to capture Anopheles in areas where wild and semi-wild ape populations live. We collected 1070 Anopheles females belonging to 15 species, among which An. carnevalei, An. moucheti and An. marshallii were the most common species. Using mtDNA-based PCR tools, we discovered that An. moucheti, a major human malaria vector in Central Africa, could also ensure the natural transmission of P. praefalciparum among great apes. We also showed that, together with An. vinckei, An. moucheti was infected with P. vivax-like parasites. An. moucheti constitutes, therefore, a major candidate for the transfer of Plasmodium parasites from apes to humans.

  19. Physarum Boats: If Plasmodium Sailed It Would Never Leave a Port

    Directory of Open Access Journals (Sweden)

    Andrew Adamatzky

    2010-01-01

    Full Text Available Plasmodium of Physarum polycephalum is a single huge (visible by naked eye cell with a myriad of nuclei. The plasmodium is a promising substrate for non-classical, nature-inspired computing devices. It is capable of approximation of the shortest path in a maze, computation of planar proximity graphs and plane tessellations, primitive memory and decision making. The unique properties of the plasmodium make it an ideal candidate for a role of amorphous biological robots with massive parallel information processing and distributed inputs and outputs. We show that when adhered to a lightweight object resting on a water surface the plasmodium can propel the object by oscillating its protoplasmic pseudopodia. In experimental laboratory conditions and computational experiments we study phenomenology of the plasmodium-floater system, and possible mechanisms of controlling motion of objects propelled by on-board plasmodium.

  20. Merozoite surface protein-1 genetic diversity in Plasmodium malariae and Plasmodium brasilianum from Brazil.

    Science.gov (United States)

    Guimarães, Lilian O; Wunderlich, Gerhard; Alves, João M P; Bueno, Marina G; Röhe, Fabio; Catão-Dias, José L; Neves, Amanda; Malafronte, Rosely S; Curado, Izilda; Domingues, Wilson; Kirchgatter, Karin

    2015-11-16

    The merozoite surface protein 1 (MSP1) gene encodes the major surface antigen of invasive forms of the Plasmodium erythrocytic stages and is considered a candidate vaccine antigen against malaria. Due to its polymorphisms, MSP1 is also useful for strain discrimination and consists of a good genetic marker. Sequence diversity in MSP1 has been analyzed in field isolates of three human parasites: P. falciparum, P. vivax, and P. ovale. However, the extent of variation in another human parasite, P. malariae, remains unknown. This parasite shows widespread, uneven distribution in tropical and subtropical regions throughout South America, Asia, and Africa. Interestingly, it is genetically indistinguishable from P. brasilianum, a parasite known to infect New World monkeys in Central and South America. Specific fragments (1 to 5) covering 60 % of the MSP1 gene (mainly the putatively polymorphic regions), were amplified by PCR in isolates of P. malariae and P. brasilianum from different geographic origin and hosts. Sequencing of the PCR-amplified products or cloned PCR fragments was performed and the sequences were used to construct a phylogenetic tree by the maximum likelihood method. Data were computed to give insights into the evolutionary and phylogenetic relationships of these parasites. Except for fragment 4, sequences from all other fragments consisted of unpublished sequences. The most polymorphic gene region was fragment 2, and in samples where this region lacks polymorphism, all other regions are also identical. The low variability of the P. malariae msp1 sequences of these isolates and the identification of the same haplotype in those collected many years apart at different locations is compatible with a low transmission rate. We also found greater diversity among P. brasilianum isolates compared with P. malariae ones. Lastly, the sequences were segregated according to their geographic origins and hosts, showing a strong genetic and geographic structure. Our data

  1. Comparative population structure of Plasmodium malariae and Plasmodium falciparum under different transmission settings in Malawi

    Directory of Open Access Journals (Sweden)

    Molyneux Malcolm E

    2011-02-01

    Full Text Available Abstract Background Described here is the first population genetic study of Plasmodium malariae, the causative agent of quartan malaria. Although not as deadly as Plasmodium falciparum, P. malariae is more common than previously thought, and is frequently in sympatry and co-infection with P. falciparum, making its study increasingly important. This study compares the population parameters of the two species in two districts of Malawi with different malaria transmission patterns - one seasonal, one perennial - to explore the effects of transmission on population structures. Methods Six species-specific microsatellite markers were used to analyse 257 P. malariae samples and 257 P. falciparum samples matched for age, gender and village of residence. Allele sizes were scored to within 2 bp for each locus and haplotypes were constructed from dominant alleles in multiple infections. Analysis of multiplicity of infection (MOI, population differentiation, clustering of haplotypes and linkage disequilibrium was performed for both species. Regression analyses were used to determine association of MOI measurements with clinical malaria parameters. Results Multiple-genotype infections within each species were common in both districts, accounting for 86.0% of P. falciparum and 73.2% of P. malariae infections and did not differ significantly with transmission setting. Mean MOI of P. falciparum was increased under perennial transmission compared with seasonal (3.14 vs 2.59, p = 0.008 and was greater in children compared with adults. In contrast, P. malariae mean MOI was similar between transmission settings (2.12 vs 2.11 and there was no difference between children and adults. Population differentiation showed no significant differences between villages or districts for either species. There was no evidence of geographical clustering of haplotypes. Linkage disequilibrium amongst loci was found only for P. falciparum samples from the seasonal transmission

  2. Molecular characterization of misidentified Plasmodium ovale imported cases in Singapore.

    Science.gov (United States)

    Chavatte, Jean-Marc; Tan, Sarah Bee Hui; Snounou, Georges; Lin, Raymond Tzer Pin Valentine

    2015-11-14

    Plasmodium ovale, considered the rarest of the malaria parasites of humans, consists of two morphologically identical but genetically distinct sympatric species, Plasmodium ovale curtisi and Plasmodium ovale wallikeri. These parasites resemble morphologically to Plasmodium vivax with which they also share a tertian periodicity and the ability to cause relapses, making them easily misidentified as P. vivax. Plasmodium ovale infections are rarely reported, but given the likelihood of misidentification, their prevalence might be underestimated. Morphological and molecular analysis of confirmed malaria cases admitted in Singapore in 2012-2014 detected nine imported P. ovale cases that had been misidentified as P. vivax. Since P. ovale had not been previously officially reported in Singapore, a retrospective analysis of available, frozen, archival blood samples was performed and returned two additional misidentified P. ovale cases in 2003 and 2006. These eleven P. ovale samples were characterized with respect to seven molecular markers (ssrRNA, Potra, Porbp2, Pog3p, dhfr-ts, cytb, cox1) used in recent studies to distinguish between the two sympatric species, and to a further three genes (tufa, clpC and asl). The morphological features of P. ovale and the differential diagnosis with P. vivax were reviewed and illustrated by microphotographs. The genetic dimorphism between P. ovale curtisi and P. ovale wallikeri was assessed by ten molecular markers distributed across the three genomes of the parasite (Genbank KP050361-KP050470). The data obtained for seven of these markers were compared with those published and confirmed that both P. ovale species were present. This dimorphism was also confirmed for the first time on: (1) two genes from the apicoplast genome (tufA and clpC genes); and, (2) the asl gene that was used for phylogenetic analyses of other Plasmodium species, and that was found to harbour the highest number of dimorphic loci between the two P. ovale species

  3. Construction of a system for heterologous production of carbonic anhydrase from Plasmodium falciparum in Pichia pastoris

    OpenAIRE

    Gullberg, Erik

    2008-01-01

    Malaria is one of the biggest current global health problems, and with the increasing occurance of drug resistant Plasmodium falciparum strains, there is an urgent need for new antimalarial drugs. Given the important role of carbonic anhydrase in Plasmodium falciparum (PfCA), it is a potential novel drug target. Heterologous expression of malaria proteins is problematic due to the unusual codon usage of the Plasmodium genome, so to overcome this problem a synthetic PfCA gene was designed, opt...

  4. Efficacy of chloroquine for the treatment of Plasmodium vivax in the Saharan zone in Mauritania

    OpenAIRE

    Ould Ahmedou Salem, Mohamed Salem; Mohamed Lemine, Yeslim Ould; Deida, Jemila Mint; Lemrabott, Mohamed Aly Ould; Ouldabdallahi, Mohamed; Ba, Mamadou dit Dialaw; Boukhary, Ali Ould Mohamed Salem; Khairy, Mohamed Lemine Ould; Abdel Aziz, Mohamed Boubacar; Ringwald, Pascal; Basco, Leonardo K; Niang, Saidou Doro; Lebatt, Sidi Mohamed

    2015-01-01

    Background: In 2006, the Mauritanian Ministry of Health adopted a new therapeutic strategy based on the systematic use of artemisinin-based combination therapy (ACT), artesunate-amodiaquine and artemether-lumefantrine, for the first-and second-line treatment of uncomplicated malaria, respectively, regardless of Plasmodium spp. In the Saharan zone of the country, recent studies have shown that Plasmodium vivax largely predominates over Plasmodium falciparum. Anti-malarial drug response of P. v...

  5. Molecular Epidemiology of Epidemic Severe Malaria Caused by Plasmodium vivax in the State of Amazonas, Brazil

    National Research Council Canada - National Science Library

    Santos-Ciminera, Patricia D

    2005-01-01

    .... In Manaus, the capital of Amazonas, atypical cases of Plasmodium vivax infections, including patients presenting with severe thrombocytopenia and bleeding, led to the hypothesis that severe disease...

  6. Plasmodium spp. in raptors on the Eurasian-African migration route.

    Science.gov (United States)

    Paperna, I; Yosef, R; Landau, I

    2007-12-01

    Examination of blood smears obtained from raptors trapped while on migration at Eilat, Israel, demonstrated Plasmodium infection in Accipiter brevipes and Buteo buteo. The following species are described, from A. brevipes: Plasmodium alloelongatum n. sp., P. accipiteris n. sp. and from B. buteo: P. buteonis n. sp. and Plasmodium sp. for which we lack sufficient data for adequate species description. Overall prevalence of infection with Plasmodium spp. was very low: among 38 examined A. brevipes 5% and among 56 B. buteo 3.6%.

  7. Plasmodium cynomolgi genome sequences provide insight into Plasmodium vivax and the monkey malaria clade.

    Science.gov (United States)

    Tachibana, Shin-Ichiro; Sullivan, Steven A; Kawai, Satoru; Nakamura, Shota; Kim, Hyunjae R; Goto, Naohisa; Arisue, Nobuko; Palacpac, Nirianne M Q; Honma, Hajime; Yagi, Masanori; Tougan, Takahiro; Katakai, Yuko; Kaneko, Osamu; Mita, Toshihiro; Kita, Kiyoshi; Yasutomi, Yasuhiro; Sutton, Patrick L; Shakhbatyan, Rimma; Horii, Toshihiro; Yasunaga, Teruo; Barnwell, John W; Escalante, Ananias A; Carlton, Jane M; Tanabe, Kazuyuki

    2012-09-01

    P. cynomolgi, a malaria-causing parasite of Asian Old World monkeys, is the sister taxon of P. vivax, the most prevalent malaria-causing species in humans outside of Africa. Because P. cynomolgi shares many phenotypic, biological and genetic characteristics with P. vivax, we generated draft genome sequences for three P. cynomolgi strains and performed genomic analysis comparing them with the P. vivax genome, as well as with the genome of a third previously sequenced simian parasite, Plasmodium knowlesi. Here, we show that genomes of the monkey malaria clade can be characterized by copy-number variants (CNVs) in multigene families involved in evasion of the human immune system and invasion of host erythrocytes. We identify genome-wide SNPs, microsatellites and CNVs in the P. cynomolgi genome, providing a map of genetic variation that can be used to map parasite traits and study parasite populations. The sequencing of the P. cynomolgi genome is a critical step in developing a model system for P. vivax research and in counteracting the neglect of P. vivax.

  8. Mosquito Vectors and the Globalization of Plasmodium falciparum Malaria.

    Science.gov (United States)

    Molina-Cruz, Alvaro; Zilversmit, Martine M; Neafsey, Daniel E; Hartl, Daniel L; Barillas-Mury, Carolina

    2016-11-23

    Plasmodium falciparum malaria remains a devastating public health problem. Recent discoveries have shed light on the origin and evolution of Plasmodium parasites and their interactions with their vertebrate and mosquito hosts. P. falciparum malaria originated in Africa from a single horizontal transfer between an infected gorilla and a human, and became global as the result of human migration. Today, P. falciparum malaria is transmitted worldwide by more than 70 different anopheline mosquito species. Recent studies indicate that the mosquito immune system can be a barrier to malaria transmission and that the P. falciparum Pfs47 gene allows the parasite to evade mosquito immune detection. Here, we review the origin and globalization of P. falciparum and integrate this history with analysis of the biology, evolution, and dispersal of the main mosquito vectors. This new perspective broadens our understanding of P. falciparum population structure and the dispersal of important parasite genetic traits.

  9. Host AMPK Is a Modulator of Plasmodium Liver Infection

    Directory of Open Access Journals (Sweden)

    Margarida T. Grilo Ruivo

    2016-09-01

    Full Text Available Manipulation of the master regulator of energy homeostasis AMP-activated protein kinase (AMPK activity is a strategy used by many intracellular pathogens for successful replication. Infection by most pathogens leads to an activation of host AMPK activity due to the energetic demands placed on the infected cell. Here, we demonstrate that the opposite is observed in cells infected with rodent malaria parasites. Indeed, AMPK activity upon the infection of hepatic cells is suppressed and dispensable for successful infection. By contrast, an overactive AMPK is deleterious to intracellular growth and replication of different Plasmodium spp., including the human malaria parasite, P. falciparum. The negative impact of host AMPK activity on infection was further confirmed in mice under conditions that activate its function. Overall, this work establishes the role of host AMPK signaling as a suppressive pathway of Plasmodium hepatic infection and as a potential target for host-based antimalarial interventions.

  10. RIFINs are adhesins implicated in severe Plasmodium falciparum malaria

    DEFF Research Database (Denmark)

    Goel, Suchi; Palmkvist, Mia; Moll, Kirsten

    2015-01-01

    Rosetting is a virulent Plasmodium falciparum phenomenon associated with severe malaria. Here we demonstrate that P. falciparum–encoded repetitive interspersed families of polypeptides (RIFINs) are expressed on the surface of infected red blood cells (iRBCs), where they bind to RBCs—preferentiall......Rosetting is a virulent Plasmodium falciparum phenomenon associated with severe malaria. Here we demonstrate that P. falciparum–encoded repetitive interspersed families of polypeptides (RIFINs) are expressed on the surface of infected red blood cells (iRBCs), where they bind to RBCs......—preferentially of blood group A—to form large rosettes and mediate microvascular binding of iRBCs. We suggest that RIFINs have a fundamental role in the development of severe malaria and thereby contribute to the varying global distribution of ABO blood groups in the human population....

  11. Evolution of Resistance to Sulfadoxine-Pyrimethamine in Plasmodium falciparum

    OpenAIRE

    Gatton, Michelle L.; Martin, Laura B; Cheng, Qin

    2004-01-01

    The development of resistance to sulfadoxine-pyrimethamine by Plasmodium parasites is a major problem for the effective treatment of malaria, especially P. falciparum malaria. Although the molecular basis for parasite resistance is known, the factors promoting the development and transmission of these resistant parasites are less clear. This paper reports the results of a quantitative comparison of factors previously hypothesized as important for the development of drug resistance, drug dosag...

  12. Larval diet affects mosquito development and permissiveness to Plasmodium infection

    OpenAIRE

    Gendrin, MEM; Christophides; Linenberg, Inbar

    2016-01-01

    The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii . We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clar...

  13. Transformation of the rodent malaria parasite Plasmodium chabaudi

    OpenAIRE

    Spence, Philip J; Cunningham, Deirdre; Jarra, William; Lawton, Jennifer; Langhorne, Jean; Thompson, Joanne

    2011-01-01

    The rodent malaria parasite Plasmodium chabaudi chabaudi shares many features with human malaria species, including P. falciparum, and is the in vivo model of choice for many aspects of malaria research in the mammalian host, from sequestration of parasitized erythrocytes, to antigenic variation and host immunity and immunopathology. this protocol describes an optimized method for the transformation of mature blood-stage P.c. chabaudi and a description of a vector that targets efficient, sing...

  14. [Morphology, biology and life-cycle of Plasmodium parasites].

    Science.gov (United States)

    Hommel, Marcel

    2007-10-01

    Laveran first discovered that an infectious agent was responsible for malaria by using a simple microscope, without the assistance of specific stains. Our knowledge of the Plasmodium life cycle and cellular biology has progressed with each technological advance, from Romanovsky staining and histology to electron microscopy, immunocytochemistry, molecular methods and modern imaging techniques. The use of bird, primate and rodent models also made a major contribution, notably in the development of antimalarial drugs that are still in use today.

  15. In vitro adaptation of Plasmodium falciparum reveal variations in cultivability

    OpenAIRE

    White, John; Mascarenhas, Anjali; Pereira, Ligia; Dash, Rashmi; Walke, Jayashri T.; Gawas, Pooja; Sharma, Ambika; Manoharan, Suresh Kumar; Guler, Jennifer L.; Maki, Jennifer N.; Kumar, Ashwani; Mahanta, Jagadish; Valecha, Neena; Dubhashi, Nagesh; Vaz, Marina

    2016-01-01

    Background Culture-adapted Plasmodium falciparum parasites can offer deeper understanding of geographic variations in drug resistance, pathogenesis and immune evasion. To help ground population-based calculations and inferences from culture-adapted parasites, the complete range of parasites from a study area must be well represented in any collection. To this end, standardized adaptation methods and determinants of successful in vitro adaption were sought. Methods Venous blood was collected f...

  16. Serological evidence of discrete spatial clusters of Plasmodium falciparum parasites

    DEFF Research Database (Denmark)

    Bejon, Philip; Turner, Louise; Lavstsen, Thomas

    2011-01-01

    Malaria transmission may be considered to be homogenous with well-mixed parasite populations (as in the classic Ross/Macdonald models). Marked fine-scale heterogeneity of transmission has been observed in the field (i.e., over a few kilometres), but there are relatively few data on the degree...... of mixing. Since the Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) is highly polymorphic, the host's serological responses may be used to infer exposure to parasite sub-populations....

  17. Plasmodium falciparum uses vitamin E to avoid oxidative stress

    OpenAIRE

    Sussmann, Rodrigo A. C.; Fotoran, Wesley L.; Kimura, Emilia A.; Katzin, Alejandro M.

    2017-01-01

    Background Plasmodium falciparum is sensitive to oxidative stress in vitro and in vivo, and many drugs such as artemisinin, chloroquine and cercosporin interfere in the parasite’s redox system. To minimize the damage caused by reactive radicals, antioxidant enzymes and their substrates found in parasites and in erythrocytes must be functionally active. It was shown that P. falciparum synthesizes vitamin E and that usnic acid acts as an inhibitor of its biosynthesis. Vitamin E is a potent anti...

  18. Interleukin-10 regulates hepcidin in Plasmodium falciparum malaria

    KAUST Repository

    Huang, Honglei

    2014-02-10

    Background: Acute malarial anemia remains a major public health problem. Hepcidin, the major hormone controlling the availability of iron, is raised during acute and asymptomatic parasitemia. Understanding the role and mechanism of raised hepcidin and so reduced iron availability during infection is critical to establish evidence-based guidelines for management of malaria anemia. Our recent clinical evidence suggests a potential role of IL-10 in the regulation of hepcidin in patients with acute P. falciparum malaria. Methods: We have measured secretion of hepcidin by primary macrophages and the hepatoma cell line HepG2 stimulated with IL-10, IL-6 and Plasmodium falciparum-infected erythrocytes. Findings: We have observed that IL-10 and IL-6 production increased in primary macrophages when these cells were co-cultured with Plasmodium falciparum-infected erythrocytes. We found that IL-10 induced hepcidin secretion in primary macrophages in a dose-dependent manner but not in HepG2 cells. These effects were mediated through signal transducer and activator of transcription (STAT) 3-phosphorylation and completely abrogated by a specific STAT3 inhibitor. Conclusion: IL-10 can directly regulate hepcidin in primary macrophages but not in HepG2 cells. This effect can be modulated by Plasmodium falciparum. The results are consistent with a role for IL-10 in modulating iron metabolism during acute phase of infection. 2014 Huang et al.

  19. [Therapeutic response of Plasmodium vivax to chloroquine in Bolivia].

    Science.gov (United States)

    Añez, Arletta; Navarro-Costa, Dennis; Yucra, Omar; Garnica, Cecilia; Melgar, Viviana; Moscoso, Manuel; Arteaga, Ricardo; Nakao, Gladys

    2012-01-01

    Knowledge of the therapeutic efficacy of chloroquine for Plasmodium vivax infections improves the capacity for surveillance of anti-malarial drug resistance. The therapeutic efficacy of chloroquine as treatment was evaluated for uncomplicated Plasmodium vivax malaria in Bolivia. An in vivo efficacy study of chloroquine was undertaken in three regions of Bolivia--Riberalta, Guayaramerín and Yacuiba. Two hundred and twenty-three patients (84, 80, and 59 in the three regions, respectively) aged over 5 years old were administered with chloroquine (25 mg/kg/three days) and followed for 28 days. Blood levels of chloroquine and desethylchloroquine were measured on day 2 and on the day of reappearance of parasitemia. The cumulative incidence of treatment failure was calculated using the Kaplan and Meier survival analysis. The mean parasitemias (asexual) on day 0 were 6,147 parasites/μl of blood in the Riberalta population, 4,251 in Guayaramerín and 5,214 in Yacuiba. The average blood concentrations of chloroquine-desethylchloroquine during day 2 were 783, 817, and 815 ng/ml, respectively. No treatment failures were observed in Yacuiba, whereas in Riberalta and Guayaramerín, the frequencies of treatment failures were 6.2% and 10%. Blood levels of chloroquine and desethylchloroquine in patients with treatment failure showed values below 70 ng/ml on the day of reappearance of parasitemia. Resistance of Plasmodium vivax to chloroquine was not demonstrated in three regions of Bolivia.

  20. Targeting Plasmodium PI(4)K to eliminate malaria

    Science.gov (United States)

    McNamara, Case W.; Lee, Marcus C. S.; Lim, Chek Shik; Lim, Siau Hoi; Roland, Jason; Nagle, Advait; Simon, Oliver; Yeung, Bryan K. S.; Chatterjee, Arnab K.; McCormack, Susan L.; Manary, Micah J.; Zeeman, Anne-Marie; Dechering, Koen J.; Kumar, T. R. Santha; Henrich, Philipp P.; Gagaring, Kerstin; Ibanez, Maureen; Kato, Nobutaka; Kuhen, Kelli L.; Fischli, Christoph; Rottmann, Matthias; Plouffe, David M.; Bursulaya, Badry; Meister, Stephan; Rameh, Lucia; Trappe, Joerg; Haasen, Dorothea; Timmerman, Martijn; Sauerwein, Robert W.; Suwanarusk, Rossarin; Russell, Bruce; Renia, Laurent; Nosten, Francois; Tully, David C.; Kocken, Clemens H. M.; Glynne, Richard J.; Bodenreider, Christophe; Fidock, David A.; Diagana, Thierry T.; Winzeler, Elizabeth A.

    2013-12-01

    Achieving the goal of malaria elimination will depend on targeting Plasmodium pathways essential across all life stages. Here we identify a lipid kinase, phosphatidylinositol-4-OH kinase (PI(4)K), as the target of imidazopyrazines, a new antimalarial compound class that inhibits the intracellular development of multiple Plasmodium species at each stage of infection in the vertebrate host. Imidazopyrazines demonstrate potent preventive, therapeutic, and transmission-blocking activity in rodent malaria models, are active against blood-stage field isolates of the major human pathogens P. falciparum and P. vivax, and inhibit liver-stage hypnozoites in the simian parasite P. cynomolgi. We show that imidazopyrazines exert their effect through inhibitory interaction with the ATP-binding pocket of PI(4)K, altering the intracellular distribution of phosphatidylinositol-4-phosphate. Collectively, our data define PI(4)K as a key Plasmodium vulnerability, opening up new avenues of target-based discovery to identify drugs with an ideal activity profile for the prevention, treatment and elimination of malaria.

  1. Primaquine for reducing Plasmodium falciparum transmission.

    Science.gov (United States)

    Graves, Patricia M; Gelband, Hellen; Garner, Paul

    2012-09-12

    Mosquitoes become infected with malaria when they ingest gametocyte stages of the parasite from the blood of a human host. Plasmodium falciparum gametocytes are sensitive to the drug primaquine (PQ). The World Health Organization (WHO) recommends giving a single dose or short course of PQ alongside primary treatment for people ill with P. falciparum infection to reduce malaria transmission. Gametocytes themselves cause no symptoms, so this intervention does not directly benefit individuals. PQ causes haemolysis in some people with glucose-6-phosphate dehydrogenase (G6PD) deficiency so may not be safe.   To assess whether a single dose or short course of PQ added to treatments for malaria caused by P. falciparum infection reduces malaria transmission and is safe. We searched the following databases up to 10 April 2012 for studies: the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; LILACS; metaRegister of Controlled Trials (mRCT) and the WHO trials search portal using 'malaria*', 'falciparum', and 'primaquine' as search terms. In addition, we searched conference proceedings and reference lists of included studies, and we contacted likely researchers and organizations for relevant trials. Trials of mass treatment of whole populations (or actively detected fever or malaria cases within such populations) with antimalarial drugs, compared to treatment with the same drug plus PQ; or patients with clinical malaria being treated for malaria at health facilities randomized to short course/single dose PQ versus no PQ. Two authors (PMG and HG) independently screened all abstracts, applied inclusion criteria, and abstracted data. We sought data on the effect of PQ on malaria transmission intensity, participant infectiousness, the number of participants with gametocytes, and gametocyte density over time. We stratified results by primary treatment drug as

  2. Close relationship of Plasmodium sequences detected from South American pampas deer (Ozotoceros bezoarticus to Plasmodium spp. in North American white-tailed deer

    Directory of Open Access Journals (Sweden)

    Masahito Asada

    2018-04-01

    Full Text Available We report, for the first time, the presence of ungulate malaria parasites in South America. We conducted PCR-based surveys of blood samples of multiple deer species and water buffalo from Brazil and detected Plasmodium sequences from pampas deer (Ozotoceros bezoarticus samples. Phylogenic analysis revealed that the obtained sequences are closely related to the Plasmodium odocoilei clade 2 sequence from North American white-tailed deer (Odocoileus virginianus. Nucleotide differences suggest that malaria parasites in South American pampas deer and North American P. odocoilei clade 2 branched more recently than the Great American Interchange. Keywords: Malaria, Pampas deer, South America, Plasmodium odocoilei, Brazil

  3. Plasmodium falciparum ookinete expression of plasmepsin VII and plasmepsin X.

    Science.gov (United States)

    Li, Fengwu; Bounkeua, Viengngeun; Pettersen, Kenneth; Vinetz, Joseph M

    2016-02-24

    Plasmodium invasion of the mosquito midgut is a population bottleneck in the parasite lifecycle. Interference with molecular mechanisms by which the ookinete invades the mosquito midgut is one potential approach to developing malaria transmission-blocking strategies. Plasmodium aspartic proteases are one such class of potential targets: plasmepsin IV (known to be present in the asexual stage food vacuole) was previously shown to be involved in Plasmodium gallinaceum infection of the mosquito midgut, and plasmepsins VII and plasmepsin X (not known to be present in the asexual stage food vacuole) are upregulated in Plasmodium falciparum mosquito stages. These (and other) parasite-derived enzymes that play essential roles during ookinete midgut invasion are prime candidates for transmission-blocking vaccines. Reverse transcriptase PCR (RT-PCR) was used to determine timing of P. falciparum plasmepsin VII (PfPM VII) and plasmepsin X (PfPM X) mRNA transcripts in parasite mosquito midgut stages. Protein expression was confirmed by western immunoblot and immunofluorescence assays (IFA) using anti-peptide monoclonal antibodies (mAbs) against immunogenic regions of PfPM VII and PfPM X. These antibodies were also used in standard membrane feeding assays (SMFA) to determine whether inhibition of these proteases would affect parasite transmission to mosquitoes. The Mann-Whitney U test was used to analyse mosquito transmission assay results. RT-PCR, western immunoblot and immunofluorescence assay confirmed expression of PfPM VII and PfPM X in mosquito stages. Whereas PfPM VII was expressed in zygotes and ookinetes, PfPM X was expressed in gametes, zygotes, and ookinetes. Antibodies against PfPM VII and PfPM X decreased P. falciparum invasion of the mosquito midgut when used at high concentrations, indicating that these proteases play a role in Plasmodium mosquito midgut invasion. Failure to generate genetic knockouts of these genes limited determination of the precise role of

  4. A bioinformatic survey of RNA-binding proteins in Plasmodium.

    Science.gov (United States)

    Reddy, B P Niranjan; Shrestha, Sony; Hart, Kevin J; Liang, Xiaoying; Kemirembe, Karen; Cui, Liwang; Lindner, Scott E

    2015-11-02

    The malaria parasites in the genus Plasmodium have a very complicated life cycle involving an invertebrate vector and a vertebrate host. RNA-binding proteins (RBPs) are critical factors involved in every aspect of the development of these parasites. However, very few RBPs have been functionally characterized to date in the human parasite Plasmodium falciparum. Using different bioinformatic methods and tools we searched P. falciparum genome to list and annotate RBPs. A representative 3D models for each of the RBD domain identified in P. falciparum was created using I-TESSAR and SWISS-MODEL. Microarray and RNAseq data analysis pertaining PfRBPs was performed using MeV software. Finally, Cytoscape was used to create protein-protein interaction network for CITH-Dozi and Caf1-CCR4-Not complexes. We report the identification of 189 putative RBP genes belonging to 13 different families in Plasmodium, which comprise 3.5% of all annotated genes. Almost 90% (169/189) of these genes belong to six prominent RBP classes, namely RNA recognition motifs, DEAD/H-box RNA helicases, K homology, Zinc finger, Puf and Alba gene families. Interestingly, almost all of the identified RNA-binding helicases and KH genes have cognate homologs in model species, suggesting their evolutionary conservation. Exploration of the existing P. falciparum blood-stage transcriptomes revealed that most RBPs have peak mRNA expression levels early during the intraerythrocytic development cycle, which taper off in later stages. Nearly 27% of RBPs have elevated expression in gametocytes, while 47 and 24% have elevated mRNA expression in ookinete and asexual stages. Comparative interactome analyses using human and Plasmodium protein-protein interaction datasets suggest extensive conservation of the PfCITH/PfDOZI and PfCaf1-CCR4-NOT complexes. The Plasmodium parasites possess a large number of putative RBPs belonging to most of RBP families identified so far, suggesting the presence of extensive post

  5. Computational identification of signalling pathways in Plasmodium falciparum.

    Science.gov (United States)

    Oyelade, Jelili; Ewejobi, Itunu; Brors, Benedikt; Eils, Roland; Adebiyi, Ezekiel

    2011-06-01

    Malaria is one of the world's most common and serious diseases causing death of about 3 million people each year. Its most severe occurrence is caused by the protozoan Plasmodium falciparum. Reports have shown that the resistance of the parasite to existing drugs is increasing. Therefore, there is a huge and urgent need to discover and validate new drug or vaccine targets to enable the development of new treatments for malaria. The ability to discover these drug or vaccine targets can only be enhanced from our deep understanding of the detailed biology of the parasite, for example how cells function and how proteins organize into modules such as metabolic, regulatory and signal transduction pathways. It has been noted that the knowledge of signalling transduction pathways in Plasmodium is fundamental to aid the design of new strategies against malaria. This work uses a linear-time algorithm for finding paths in a network under modified biologically motivated constraints. We predicted several important signalling transduction pathways in Plasmodium falciparum. We have predicted a viable signalling pathway characterized in terms of the genes responsible that may be the PfPKB pathway recently elucidated in Plasmodium falciparum. We obtained from the FIKK family, a signal transduction pathway that ends up on a chloroquine resistance marker protein, which indicates that interference with FIKK proteins might reverse Plasmodium falciparum from resistant to sensitive phenotype. We also proposed a hypothesis that showed the FIKK proteins in this pathway as enabling the resistance parasite to have a mechanism for releasing chloroquine (via an efflux process). Furthermore, we also predicted a signalling pathway that may have been responsible for signalling the start of the invasion process of Red Blood Cell (RBC) by the merozoites. It has been noted that the understanding of this pathway will give insight into the parasite virulence and will facilitate rational vaccine design

  6. The epidemiology of Plasmodium vivax and Plasmodium falciparum malaria in China, 2004-2012: from intensified control to elimination.

    Science.gov (United States)

    Zhang, Qian; Lai, Shengjie; Zheng, Canjun; Zhang, Honglong; Zhou, Sheng; Hu, Wenbiao; Clements, Archie C A; Zhou, Xiao-Nong; Yang, Weizhong; Hay, Simon I; Yu, Hongjie; Li, Zhongjie

    2014-11-03

    In China, the national malaria elimination programme has been operating since 2010. This study aimed to explore the epidemiological changes in patterns of malaria in China from intensified control to elimination stages. Data on nationwide malaria cases from 2004 to 2012 were extracted from the Chinese national malaria surveillance system. The secular trend, gender and age features, seasonality, and spatial distribution by Plasmodium species were analysed. In total, 238,443 malaria cases were reported, and the proportion of Plasmodium falciparum increased drastically from population. The areas affected by Plasmodium vivax malaria shrunk, while areas affected by P. falciparum malaria expanded from 294 counties in 2004 to 600 counties in 2012. This study demonstrated that malaria has decreased dramatically in the last five years, especially since the Chinese government launched a malaria elimination programme in 2010, and areas with reported falciparum malaria cases have expanded over recent years. These findings suggest that elimination efforts should be improved to meet these changes, so as to achieve the nationwide malaria elimination goal in China in 2020.

  7. Molecular Detection of Plasmodium malariae/Plasmodium brasilianum in Non-Human Primates in Captivity in Costa Rica.

    Science.gov (United States)

    Fuentes-Ramírez, Alicia; Jiménez-Soto, Mauricio; Castro, Ruth; Romero-Zuñiga, Juan José; Dolz, Gaby

    2017-01-01

    One hundred and fifty-two blood samples of non-human primates of thirteen rescue centers in Costa Rica were analyzed to determine the presence of species of Plasmodium using thick blood smears, semi-nested multiplex polymerase chain reaction (SnM-PCR) for species differentiation, cloning and sequencing for confirmation. Using thick blood smears, two samples were determined to contain the Plasmodium malariae parasite, with SnM-PCR, a total of five (3.3%) samples were positive to P. malariae, cloning and sequencing confirmed both smear samples as P. malariae. One sample amplified a larger and conserved region of 18S rDNA for the genus Plasmodium and sequencing confirmed the results obtained microscopically and through SnM-PCR tests. Sequencing and construction of a phylogenetic tree of this sample revealed that the P. malariae/P. brasilianum parasite (GenBank KU999995) found in a howler monkey (Alouatta palliata) is identical to that recently reported in humans in Costa Rica. The SnM-PCR detected P. malariae/P. brasilianum parasite in different non-human primate species in captivity and in various regions of the southern Atlantic and Pacific coast of Costa Rica. The similarity of the sequences of parasites found in humans and a monkey suggests that monkeys may be acting as reservoirs of P.malariae/P. brasilianum, for which reason it is important, to include them in control and eradication programs.

  8. Cytokine balance in human malaria: does Plasmodium vivax elicit more inflammatory responses than Plasmodium falciparum?

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    Raquel M Gonçalves

    Full Text Available BACKGROUND: The mechanisms by which humans regulate pro- and anti-inflammatory responses on exposure to different malaria parasites remains unclear. Although Plasmodium vivax usually causes a relatively benign disease, this parasite has been suggested to elicit more host inflammation per parasitized red blood cell than P. falciparum. METHODOLOGY/PRINCIPAL FINDINGS: We measured plasma concentrations of seven cytokines and two soluble tumor necrosis factor (TNF-α receptors, and evaluated clinical and laboratory outcomes, in Brazilians with acute uncomplicated infections with P. vivax (n = 85, P. falciparum (n = 30, or both species (n = 12, and in 45 asymptomatic carriers of low-density P. vivax infection. Symptomatic vivax malaria patients, compared to those infected with P. falciparum or both species, had more intense paroxysms, but they had no clear association with a pro-inflammatory imbalance. To the contrary, these patients had higher levels of the regulatory cytokine interleukin (IL-10, which correlated positively with parasite density, and elevated IL-10/TNF-α, IL-10/interferon (IFN-γ, IL-10/IL-6 and sTNFRII/TNF-α ratios, compared to falciparum or mixed-species malaria patient groups. Vivax malaria patients had the highest levels of circulating soluble TNF-α receptor sTNFRII. Levels of regulatory cytokines returned to normal values 28 days after P. vivax clearance following chemotherapy. Finally, asymptomatic carriers of low P. vivax parasitemias had substantially lower levels of both inflammatory and regulatory cytokines than did patients with clinical malaria due to either species. CONCLUSIONS: Controlling fast-multiplying P. falciparum blood stages requires a strong inflammatory response to prevent fulminant infections, while reducing inflammation-related tissue damage with early regulatory cytokine responses may be a more cost-effective strategy in infections with the less virulent P. vivax parasite. The early induction

  9. Antimalarial iron chelator, FBS0701, shows asexual and gametocyte Plasmodium falciparum activity and single oral dose cure in a murine malaria model.

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    Patricia Ferrer

    Full Text Available Iron chelators for the treatment of malaria have proven therapeutic activity in vitro and in vivo in both humans and mice, but their clinical use is limited by the unsuitable absorption and pharmacokinetic properties of the few available iron chelators. FBS0701, (S3"-(HO-desazadesferrithiocin-polyether [DADFT-PE], is an oral iron chelator currently in Phase 2 human studies for the treatment of transfusional iron overload. The drug has very favorable absorption and pharmacokinetic properties allowing for once-daily use to deplete circulating free iron with human plasma concentrations in the high µM range. Here we show that FBS0701 has inhibition concentration 50% (IC(50 of 6 µM for Plasmodium falciparum in contrast to the IC(50 for deferiprone and deferoxamine at 15 and 30 µM respectively. In combination, FBS0701 interfered with artemisinin parasite inhibition and was additive with chloroquine or quinine parasite inhibition. FBS0701 killed early stage P. falciparum gametocytes. In the P. berghei Thompson suppression test, a single dose of 100 mg/kg reduced day three parasitemia and prolonged survival, but did not cure mice. Treatment with a single oral dose of 100 mg/kg one day after infection with 10 million lethal P. yoelii 17XL cured all the mice. Pretreatment of mice with a single oral dose of FBS0701 seven days or one day before resulted in the cure of some mice. Plasma exposures and other pharmacokinetics parameters in mice of the 100 mg/kg dose are similar to a 3 mg/kg dose in humans. In conclusion, FBS0701 demonstrates a single oral dose cure of the lethal P. yoelii model. Significantly, this effect persists after the chelator has cleared from plasma. FBS0701 was demonstrated to remove labile iron from erythrocytes as well as enter erythrocytes to chelate iron. FBS0701 may find clinically utility as monotherapy, a malarial prophylactic or, more likely, in combination with other antimalarials.

  10. New approach for high-throughput screening of drug activity on Plasmodium liver stages.

    NARCIS (Netherlands)

    Gego, A.; Silvie, O.; Franetich, J.F.; Farhati, K.; Hannoun, L.; Luty, A.J.F.; Sauerwein, R.W.; Boucheix, C.; Rubinstein, E.; Mazier, D.

    2006-01-01

    Plasmodium liver stages represent potential targets for antimalarial prophylactic drugs. Nevertheless, there is a lack of molecules active on these stages. We have now developed a new approach for the high-throughput screening of drug activity on Plasmodium liver stages in vitro, based on an

  11. Bionomics of Anopheles latens in Kapit, Sarawak, Malaysian Borneo in relation to the transmission of zoonotic simian malaria parasite Plasmodium knowlesi

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    Matusop Asmad

    2008-03-01

    Full Text Available Abstract Background A large focus of human infections with Plasmodium knowlesi, a simian parasite naturally found in long-tailed and pig-tailed macaques was discovered in the Kapit Division of Sarawak, Malaysian Borneo. A study was initiated to identify the vectors of malaria, to elucidate where transmission is taking place and to understand the bionomics of the vectors in Kapit. Methods Three different ecological sites in the forest, farm and longhouse in the Kapit district were selected for the study. Mosquitoes were collected by human landing collection at all sites and at the forest also by monkey-baited-traps situated on three different levels. All mosquitoes were identified and salivary glands and midguts of anopheline mosquitoes were dissected to determine the presence of malaria parasites. Results and Discussions Over an 11-month period, a total of 2,504 Anopheles mosquitoes comprising 12 species were caught; 1,035 at the farm, 774 at the forest and 425 at the longhouse. Anopheles latens (62.3% and Anopheles watsonii (30.6% were the predominant species caught in the forested ecotypes, while in the farm Anopheles donaldi (49.9% and An. latens (35.6% predominated. In the long house, An. latens (29.6% and An. donaldi (22.8% were the major Anopheline species. However, An. latens was the only mosquito positive for sporozoites and it was found to be attracted to both human and monkey hosts. In monkey-baited net traps, it preferred to bite monkeys at the canopy level than at ground level. An. latens was found biting early as 18.00 hours. Conclusion Anopheles latens is the main vector for P. knowlesi malaria parasites in the Kapit District of Sarawak, Malaysian Borneo. The study underscores the relationship between ecology, abundance and bionomics of anopheline fauna. The simio-anthropophagic and acrodendrophilic behaviour of An. latens makes it an efficient vector for the transmission of P. knowlesi parasites to both human and monkey hosts.

  12. The synthetic Plasmodium falciparum circumsporozoite peptide PfCS102 as a malaria vaccine candidate: a randomized controlled phase I trial.

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    Régine Audran

    Full Text Available BACKGROUND: Fully efficient vaccines against malaria pre-erythrocytic stage are still lacking. The objective of this dose/adjuvant-finding study was to evaluate the safety, reactogenicity and immunogenicity of a vaccine candidate based on a peptide spanning the C-terminal region of Plasmodium falciparum circumsporozoite protein (PfCS102 in malaria naive adults. METHODOLOGY AND PRINCIPAL FINDINGS: Thirty-six healthy malaria-naive adults were randomly distributed into three dose blocks (10, 30 and 100 microg and vaccinated with PfCS102 in combination with either Montanide ISA 720 or GSK proprietary Adjuvant System AS02A at days 0, 60, and 180. Primary end-point (safety and reactogenicity was based on the frequency of adverse events (AE and of abnormal biological safety tests; secondary-end point (immunogenicity on P. falciparum specific cell-mediated immunity and antibody response before and after immunization. The two adjuvant formulations were well tolerated and their safety profile was good. Most AEs were local and, when systemic, involved mainly fatigue and headache. Half the volunteers in AS02A groups experienced severe AEs (mainly erythema. After the third injection, 34 of 35 volunteers developed anti-PfCS102 and anti-sporozoite antibodies, and 28 of 35 demonstrated T-cell proliferative responses and IFN-gamma production. Five of 22 HLA-A2 and HLA-A3 volunteers displayed PfCS102 specific IFN-gamma secreting CD8(+ T cell responses. Responses were only marginally boosted after the 3(rd vaccination and remained stable for 6 months. For both adjuvants, the dose of 10 microg was less immunogenic in comparison to 30 and 100 microg that induced similar responses. AS02A formulations with 30 microg or 100 microg PfCS102 induced about 10-folds higher antibody and IFN-gamma responses than Montanide formulations. CONCLUSIONS/SIGNIFICANCE: PfCS102 peptide was safe and highly immunogenic, allowing the design of more advanced trials to test its potential

  13. Biological, immunological and functional properties of two novel multi-variant chimeric recombinant proteins of CSP antigens for vaccine development against Plasmodium vivax infection.

    Science.gov (United States)

    Shabani, Samaneh H; Zakeri, Sedigheh; Salmanian, Ali H; Amani, Jafar; Mehrizi, Akram A; Snounou, Georges; Nosten, François; Andolina, Chiara; Mourtazavi, Yousef; Djadid, Navid D

    2017-10-01

    The circumsporozoite protein (CSP) of the malaria parasite Plasmodium vivax is a major pre-erythrocyte vaccine candidate. The protein has a central repeat region that belongs to one of repeat families (VK210, VK247, and the P. vivax-like). In the present study, computer modelling was employed to select chimeric proteins, comprising the conserved regions and different arrangements of the repeat elements (VK210 and VK247), whose structure is similar to that of the native counterparts. DNA encoding the selected chimeras (named CS127 and CS712) were synthetically constructed based on E. coli codons, then cloned and expressed. Mouse monoclonal antibodies (mAbs; anti-Pv-210-CDC and -Pv-247-CDC), recognized the chimeric antigens in ELISA, indicating correct conformation and accessibility of the B-cell epitopes. ELISA using IgG from plasma samples collected from 221 Iranian patients with acute P. vivax showed that only 49.32% of the samples reacted to both CS127 and CS712 proteins. The dominant subclass for the two chimeras was IgG1 (48% of the positive responders, OD 492 =0.777±0.420 for CS127; 48.41% of the positive responders, OD 492 =0.862±0.423 for CS712, with no statistically significant difference P>0.05; Wilcoxon signed ranks test). Binding assays showed that both chimeric proteins bound to immobilized heparan sulphate and HepG2 hepatocyte cells in a concentration-dependent manner, saturable at 80μg/mL. Additionally, anti-CS127 and -CS712 antibodies raised in mice recognized the native protein on the surface of P. vivax sporozoite with high intensity, confirming the presence of common epitopes between the recombinant forms and the native proteins. In summary, despite structural differences at the molecular level, the expression levels of both chimeras were satisfactory, and their conformational structure retained biological function, thus supporting their potential for use in the development of vivax-based vaccine. Copyright © 2017 Elsevier Ltd. All rights

  14. Bionomics of Anopheles latens in Kapit, Sarawak, Malaysian Borneo in relation to the transmission of zoonotic simian malaria parasite Plasmodium knowlesi

    Science.gov (United States)

    Tan, Cheong H; Vythilingam, Indra; Matusop, Asmad; Chan, Seng T; Singh, Balbir

    2008-01-01

    Background A large focus of human infections with Plasmodium knowlesi, a simian parasite naturally found in long-tailed and pig-tailed macaques was discovered in the Kapit Division of Sarawak, Malaysian Borneo. A study was initiated to identify the vectors of malaria, to elucidate where transmission is taking place and to understand the bionomics of the vectors in Kapit. Methods Three different ecological sites in the forest, farm and longhouse in the Kapit district were selected for the study. Mosquitoes were collected by human landing collection at all sites and at the forest also by monkey-baited-traps situated on three different levels. All mosquitoes were identified and salivary glands and midguts of anopheline mosquitoes were dissected to determine the presence of malaria parasites. Results and Discussions Over an 11-month period, a total of 2,504 Anopheles mosquitoes comprising 12 species were caught; 1,035 at the farm, 774 at the forest and 425 at the longhouse. Anopheles latens (62.3%) and Anopheles watsonii (30.6%) were the predominant species caught in the forested ecotypes, while in the farm Anopheles donaldi (49.9%) and An. latens (35.6%) predominated. In the long house, An. latens (29.6%) and An. donaldi (22.8%) were the major Anopheline species. However, An. latens was the only mosquito positive for sporozoites and it was found to be attracted to both human and monkey hosts. In monkey-baited net traps, it preferred to bite monkeys at the canopy level than at ground level. An. latens was found biting early as 18.00 hours. Conclusion Anopheles latens is the main vector for P. knowlesi malaria parasites in the Kapit District of Sarawak, Malaysian Borneo. The study underscores the relationship between ecology, abundance and bionomics of anopheline fauna. The simio-anthropophagic and acrodendrophilic behaviour of An. latens makes it an efficient vector for the transmission of P. knowlesi parasites to both human and monkey hosts. PMID:18377652

  15. Spatial variation in genetic diversity and natural selection on the thrombospondin-related adhesive protein locus of Plasmodium vivax (PvTRAP.

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    Rattiporn Kosuwin

    Full Text Available Thrombospondin-related adhesive protein (TRAP of malaria parasites is essential for sporozoite motility and invasions into mosquito's salivary gland and vertebrate's hepatocyte; thereby, it is a promising target for pre-erythrocytic vaccine. TRAP of Plasmodium vivax (PvTRAP exhibits sequence heterogeneity among isolates, an issue relevant to vaccine development. To gain insights into variation in the complete PvTRAP sequences of parasites in Thailand, 114 vivax malaria patients were recruited in 2006-2007 from 4 major endemic provinces bordering Myanmar (Tak in the northwest, n = 30 and Prachuap Khirikhan in the southwest, n = 25, Cambodia (Chanthaburi in the east, n = 29 and Malaysia (Yala and Narathiwat in the south, n = 30. In total, 26 amino acid substitutions were detected and 9 of which were novel, resulting in 44 distinct haplotypes. Haplotype and nucleotide diversities were lowest in southern P. vivax population while higher levels of diversities were observed in other populations. Evidences of positive selection on PvTRAP were demonstrated in domains II and IV and purifying selection in domains I, II and VI. Genetic differentiation was significant between each population except that between populations bordering Myanmar where transmigration was common. Regression analysis of pairwise linearized Fst and geographic distance suggests that P. vivax populations in Thailand have been isolated by distance. Sequence diversity of PvTRAP seems to be temporally stable over one decade in Tak province based on comparison of isolates collected in 1996 (n = 36 and 2006-2007. Besides natural selection, evidences of intragenic recombination have been supported in this study that could maintain and further generate diversity in this locus. It remains to be investigated whether amino acid substitutions in PvTRAP could influence host immune responses although several predicted variant T cell epitopes drastically altered the epitope

  16. The immunogenicity of Eimeria tenella sporozoite proteins and living oocyst vaccines in broilersImunogenicidade de vacina com proteínas de esporozoítos e oocistos vivos de Eimeria tenella em frangos

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    Odilon Vidotto

    2012-02-01

    Full Text Available The purpose of the present study was to evaluate the immunity of broilers inoculated with sporulated oocysts and sporozoite proteins of Eimeria tenella against challenge with homologous infectives oocysts. Broiler chickens of Hubbard strain, females, coccidian-free, were kept in wire cages and inoculated on the third day (day 0. Three treatments were used: T1, the negative control; T2, received 500 sporulated oocysts by gavage; T3, positive control; T4, received 50 ?g of sporozoite protein with Quil A; and T5, received Quil A without sporozoite protein and PBS, the last two protocols were administered via nasal route on days 0, 7, and 21. On the 31st day, all groups, with the exception of T1, were challenged with homologous virulent strain of E. tenella at the dose of 8.0×104 oocysts. Immunogenicity was assessed by carotenoids, ELISA assay, histopathological analysis, oocysts count and lesion score. Antibody kinetics were measured weekly and showed a gradual increase in levels of immunoglobulin for treatment T2 and T4, reaching a peak on day 21. Based on the parameters evaluated, a total protecting immunological effect for the infectant oocysts vaccine (T2 and partial protection for the sporozoite protein vaccine (T4 against homologous virulent strain challenge were observed. O objetivo do presente estudo foi avaliar a imunidade de frangos de corte inoculados com oocistos esporulados e proteínas de esporozoítos de Eimeria tenella utilizando um desafio com oocistos esporulados homólogos. Frangos de corte da linhagem Hubbard, fêmeas, livres de coccidiose, foram mantidos em gaiolas de arame e inoculados no terceiro dia (dia 0. O delineamento experimental consistiu de cinco tratamentos com três repetições: T1- controle negativo; T2- recebeu 500 oocistos esporulados por gavagem; T3- controle positivo; T4- receberam 50 ?g de proteína de esporozoítos adicionados a Quil-A, e finalmente o T5- que recebeu apenas Quil A e PBS, os últimos dois

  17. Cell based assays for anti-Plasmodium activity evaluation.

    Science.gov (United States)

    Mokgethi-Morule, Thabang; N'Da, David D

    2016-03-10

    Malaria remains one of the most common and deadly infectious diseases worldwide. The severity of this global public health challenge is reflected by the approximately 198 million people, who were reportedly infected in 2013 and by the more than 584,000 related deaths in that same year. The rising emergence of drug resistance towards the once effective artemisinin combination therapies (ACTs) has become a serious concern and warrants more robust drug development strategies, with the objective of eradicating malaria infections. The intricate biology and life cycle of Plasmodium parasites complicate the understanding of the disease in such a way that would enhance the development of more effective chemotherapies that would achieve radical clinical cure and that would prevent disease relapse. Phenotypic cell based assays have for long been a valuable approach and involve the screening and analysis of diverse compounds with regards to their activities towards whole Plasmodium parasites in vitro. To achieve the Millennium Development Goal (MDG) of malaria eradication by 2020, new generation drugs that are active against all parasite stages (erythrocytic (blood), exo-erythrocytic (liver stages and gametocytes)) are needed. Significant advances are being made in assay development to overcome some of the practical challenges of assessing drug efficacy, particularly in the liver and transmission stage Plasmodium models. This review discusses primary screening models and the fundamental progress being made in whole cell based efficacy screens of anti-malarial activity. Ongoing challenges and some opportunities for improvements in assay development that would assist in the discovery of effective, safe and affordable drugs for malaria treatments are also discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Epidemiology and Control of Plasmodium vivax in Afghanistan

    Science.gov (United States)

    Leslie, Toby; Nahzat, Sami; Sediqi, Walid

    2016-01-01

    Around half of the population of Afghanistan resides in areas at risk of malaria transmission. Two species of malaria (Plasmodium vivax and Plasmodium falciparum) account for a high burden of disease—in 2011, there were more than 300,000 confirmed cases. Around 80–95% of malaria is P. vivax. Transmission is seasonal and focal, below 2,000 m in altitude, and in irrigated areas which allow breeding of anopheline mosquito vectors. Malaria risk is stratified to improve targeting of interventions. Sixty-three of 400 districts account for ∼85% of cases, and are the target of more intense control efforts. Pressure on the disease is maintained through case management, surveillance, and use of long-lasting insecticide-treated nets. Plasmodium vivax treatment is hampered by the inability to safely treat latent hypnozoites with primaquine because G6PD deficiency affects up to 10% of males in some ethnic groups. The risk of vivax malaria recurrence (which may be as a result of reinfection or relapse) is around 30–45% in groups not treated with primaquine but 3–20% in those given 14-day or 8-week courses of primaquine. Greater access to G6PD testing and radical treatment would reduce the number of incident cases, reduce the infectious reservoir in the population, and has the potential to reduce transmission as a result. Alongside the lack of G6PD testing, under-resourcing and poor security hamper the control of malaria. Recent gains in reducing the burden of disease are fragile and at risk of reversal if pressure on the disease is not maintained. PMID:27708189

  19. The Plasmodium bottleneck: malaria parasite losses in the mosquito vector

    Science.gov (United States)

    Smith, Ryan C; Vega-Rodríguez, Joel; Jacobs-Lorena, Marcelo

    2014-01-01

    Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission. PMID:25185005

  20. Penemuan Baru Plasmodium Knowlesi pada Manusia di Kalimantan Tengah

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    Sahat Ompusunggu

    2015-07-01

    Full Text Available AbstractUntil 2012, four Plasmodium knowlesi malaria cases had been found in South Kalimantan. Objectives of this study were to determine the proporsion of P. knowlesi among microscopically positive malaria cases, clinical symptoms and morphology of P. knowlesi. This study is conductedin Central Kalimantan and South Kalimantan in 2013-2014. Samples were microscopically positive malaria cases obtained by surveys and passive case findings. Finger’s blood absorbed on filter papers or scraping of thick blood films were examined by polymerase chain reaction. Patients were also examined clinically and interviewed to investigate the history of infections. The results showed that among the 287 samples examined, three samples (1.05% positive P. knowlesi. All of the three cases were infected locally, which consist of two in Central Kalimantan and one in South Kalimantan. The cases in Central Kalimantan were the first finding of Plasmodium knowlesi malaria cases in the province. Clinical symptoms in two cases were mild but in another case was rather severe. Morphology of P. knowlesi has a special characteristic although it resembles P. falciparum, P. vivax and P. malariae. Further research is needed in order to find other spreading area of P. knowlesi malaria in Indonesia.Keywords : Plasmodium knowlesi, human, clinical symptoms, morphology, Central Kalimantan.AbstrakSampai tahun 2012, empat kasus malaria Plamodium knowlesi pada manusia yang penularannya di sekitar hutan telah ditemukan di Kalimantan Selatan. Tujuan penelitian ini adalah untuk mengetahui besarnya proporsi P. knowlesi di antara kasus malaria positif mikroskopis, gejala klinis dan morfologi P. knowlesi. Penelitian ini dilakukan di Kalimantan Tengah dan Kalimantan Selatan pada tahun 2013-2014. Sampel adalah kasus malaria positif mikroskopis yang diperoleh melalui survei dan penemuan kasus secara pasif. Serapan darah pada kertas saring atau kerokan sediaan apus darah tebal diperiksa dengan

  1. The Plasmodium bottleneck: malaria parasite losses in the mosquito vector

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    Ryan C Smith

    2014-08-01

    Full Text Available Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission.

  2. PLASMODIUM KNOWLESI: DISTRIBUSI, GAMBARAN MIKROSKOPIS, GEJALA PENDERITA DAN VEKTOR POTENSIAL

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    Lasbudi Pertama Ambarita

    2016-07-01

    Full Text Available ABSTRACTMalaria in humans is caused by an infection of genus Plasmodium, especially P. falciparum, P. vivax.P.mulariae and P. ovate. Types of Plasmodium in animals that can inject humans is P. knowlesi. Animalswhich are found parasites in their body are long tailed macaques (Macaca fascicularis and pig-tailedmacaques (Macaca nemestrina. .There have been many cases with positive malaria knowlesi as ithappened in Malaysia, Singapore, Thailand, Philippines, Myanmar, China, Vietnam and Indonesia. Studyof P. knowlesi aims to give an overview of the • case distribution, microscopic. features, patient characteristic, potential vector, as well as potential spread of malaria knowlesi in Indonesia. The methodused in this study is study literature from various sources. The microscopic features of the parasite inpatient blood films is pretty similar to P. falciparum and P. malariae in certain stadium. Therefore more awareness are needed regarding the spread of this parasite, especially in border areas of malaria endemiccountries and newly arrived immigrants in endemic areas of P. knowlesi.Keywords: Plasmodium knowlesi, malaria, parasite, vector ABSTRAKMalaria pada manusia selama ini disebabkan oleh infeksi genusPlasmodiumkhususnyaP. falciparum, P.vivax, P. malariaedanP. ovate. JenisPlasmodiumpada hewan yang dapat menginfeksi manusia adalahP.knowlesi.Hewan yang banyak ditemukan parasit ini dalam tubuhnya adalah kera ekor panjang(Macacajascicularisdan kera ekor babi(Macaca nemestrina.Sudah banyak kasus penderita malaria yang positif parasit ini seperti yang terjadi di Malaysia, Singapura, Thailand, Filipina, Myanmar, Cina, Vietnam danIndonesia. Kajian tentangP. knowlesiini bertujuan untuk memberikan gambaran tentang penyebarankasus, gambaran mikroskopis, karakteristik penderita, vektor potensial serta potensi penyebaran malaria knowlesidi Indonesia. Metode yang digunakan dalam kajian ini adalah studi kepustakaan (literatur dariberbagai sumber. Secara

  3. Oligohydramnios in a pregnant Pakistani woman with Plasmodium vivax malaria

    OpenAIRE

    Binello, Nicolò; Brunetti, Enrico; Cattaneo, Federico; Lissandrin, Raffaella; Malfitano, Antonello

    2014-01-01

    In the Western world, the diagnosis and management of Plasmodium vivax malaria in pregnant women can be challenging, and the pathogenesis of adverse outcomes for both the mother and the foetus is still poorly known. The authors describe the case of a 29-year-old Pakistani woman at the 29th week of her second pregnancy, who was admitted to the Hospital following the abrupt onset of fever. At the time of admission, she had been living in Italy without travelling to any malaria-endemic areas for...

  4. frequency and seasonal variation of plasmodium species in southern districts of Khyber pakhtunkhwa

    International Nuclear Information System (INIS)

    Khan, N.U.

    2014-01-01

    To determine the frequency of malaria and seasonal variation of Plasmodium species in southern districts of Khyber Pakhtunkhwa. Study Design: Descriptive study. Place and Duration of study: Department of Pathology Combined Military Hospital (CMH), Bannu, from 1st January 2010 to 31st December 2011. Patients and Methods: Five thousand eight hundred and seventy eight (5878) patients with symptoms of fever, nausea, malaise and body aches irrespective of age and gender were included in the study. Samples were collected, thin and thick smears of