Population dynamics of Plasmodium sporogony

Vaughan, Jefferson A.

doi:10.1016/j.pt.2006.12.009

Cited by 96 publications

(100 citation statements)

References 49 publications

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“…Such an aggregated distribution is well known in natural systems (Billingsley et al 1994), resulting from natural variation in mosquito susceptibility (Riehle et al 2006) and parasite apoptosis when at high densities within the mosquito (Al-Olayan et al 2002;Hurd et al 2005). High levels of parasite death occurring during the early stages of development in the mosquito (Vaughan 2007) probably smother any discernible direct effects of gametocyte phenotypes (density and sex ratio) on oocyst number.…”

Section: Discussionmentioning

confidence: 99%

Density-dependent impact of the human malaria parasite Plasmodium falciparum gametocyte sex ratio on mosquito infection rates

et al. 2009

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Malaria parasites produce male and female life cycle stages (gametocytes) that must fertilize to achieve successful colonization of the mosquito. Gametocyte sex ratios have been shown to be under strong selection pressure both as an adaptive response to a worsening blood environment for transmission and according to the number of co-infecting clones in the vertebrate. Evidence for an impact of sex ratio on the transmission success of Plasmodium falciparum has, however, been more controversial. Theoretical models of fertilization predict that increasingly male sex ratios will be favoured at low gametocyte densities to ensure fertilization. Here, we analyse in vitro transmission studies of P. falciparum to Anopheles gambiae mosquitoes and test this prediction. We find that there is a discernible effect of sex ratio on transmission but which is dependent upon the gametocyte density. While increasingly male sex ratios do give higher transmission success at low gametocyte densities, they reduce success at higher densities. This therefore provides empirical confirmation that sex ratio has an immediate impact on transmission success and that it is density-dependent. Identifying the signals used by the parasite to alter its sex ratio is essential to determine the success of transmission-blocking vaccines that aim to impede the fertilization process.

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Section: Discussionmentioning

confidence: 99%

Density-dependent impact of the human malaria parasite Plasmodium falciparum gametocyte sex ratio on mosquito infection rates

et al. 2009

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“…These zygotes develop into motile ookinetes (4n) (36) that ultimately become embedded in the basal lamina beneath the midgut epithelial wall as oocysts (14). Over the course of several days, a single oocyst undergoes 10 to 11 rounds of DNA synthesis and mitosis to create a syncytial cell (sporoblast) with thousands of nuclei (61,70,82). In a massive cytokinesis event, thousands of haploid (1n) daughter sporozoites assemble from the surface of the mother cell (61, 67), and these infective sporozoites then migrate to the mosquito salivary glands for transmission to the host.…”

Section: Serial Mitosis Is a Common Theme In Malaria Parasite Reprodumentioning

confidence: 99%

Mitosis in the Human Malaria Parasite Plasmodium falciparum

2011

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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 contributing factor for their pathogenesis in the host. As with other eukaryotes, successful mitosis is an essential requirement for Plasmodium reproduction; however, some aspects of Plasmodium mitosis are quite distinct and not fully understood. In this review, we will discuss the current understanding of the architecture and key events of mitosis in Plasmodium falciparum and related parasites and compare them with the traditional mitotic events described for other eukaryotes. SERIAL MITOSIS IS A COMMON THEME IN MALARIA PARASITE REPRODUCTIONThere are four critical points in the life cycle of Plasmodium parasites in which a small number of parasites rapidly multiply to generate much larger populations (60). These life cycle stages are male gamete development (72), sporozoite formation (5, 13), liver-stage development (68), and blood-stage asexual reproduction (9, 60). The first two of these processes occur within the mosquito vector, and the second two processes take place in the vertebrate host. During each of these Plasmodium life cycle stages, the parasites increase their numbers by using serial rounds of mitosis to create multinuclear cells and then orchestrating mass cytokinesis events to release their progeny (71). Mitosis is the process by which eukaryotic cells segregate their chromosomes in preparation for cell division (33,47,51).To create male gametes in preparation for sexual reproduction, the parasite begins with a haploid (1n) cell called a microgametocyte which is ingested by the mosquito during a blood meal (34,72). Within 12 min, this microgametocyte undergoes three rapid rounds of DNA synthesis and mitosis to generate a cell with an 8n genomic complement (35,36,73). Over the next 3 min, these genomes separate from one another and eight new haploid (1n) male gametes begin to assemble from the surface of the original cell (4, 69, 71).Within the mosquito midgut, a small number of the male gametes will fuse with female gametes that have also developed in this compartment, and this fusion will create diploid (2n) zygotes (15). These zygotes develop into motile ookinetes (4n) (36) that ultimately become embedded in the basal lamina beneath the midgut epithelial wall as oocysts (14). Over the course of several days, a single oocyst undergoes 10 to 11 rounds of DNA synthesis and mitosis to create a syncytial cell (sporoblast) with thousands of nuclei (61,70,82). In a massive cytokinesis event, thousands of haploid (1n) daughter sporozoites assemble from the surface of the mother cell (61, 67), and these infective sporozo...

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“…Sporogony of malaria parasite in the mosquito host involves transition into four different stages and penetration of two different epithelia. A considerable number of parasites are lost at each transition stage during its development in the mosquito midgut (Zollner et al 2006, Vaughan 2007. Various laboratory and Þeld studies have shown that some strains of mosquitoes are highly susceptible to malaria transmission, whereas others do not allow any parasite to develop (Collins et al 1986, Adak et al 2005.…”

Section: Resultsmentioning

confidence: 99%

Comparative Susceptibilities of Species T and U of theAnopheles fluviatilisComplex toPlasmodium vinckei petteriSporogony

et al. 2013

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Anopheles fluviatilis James is an important malaria vector in Indian subcontinent. An. fluviatilis exists as a complex of three sibling species, of which two species, T and U, have been colonized so far. Attempts were made to study the comparative susceptibility of species T and U of the An. fluviatilis complex to rodent malaria parasite Plasmodium vinckei petteri by using Anopheles stephensi Liston as calibrator for variable infectivity in different isolates. An. stephensi, which was used as control, became readily infected, with 60-65% mosquitoes carrying developing oocysts, whereas in species T and species U, approximately 50 and 63%, respectively, of mosquitoes carried oocyts. An. fluviatilis species T was found comparatively less susceptible to P. v. petteri sporogonic development compared with species U. Moreover, significantly lesser sporozoites rate (11%) was observed in species T compared with 31% in species U. Species T and species U are not considered as malaria vectors in India in the field. However, in the laboratory, both these species are able to support the malaria sporogony.

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Population dynamics of Plasmodium sporogony

Cited by 96 publications

References 49 publications

Density-dependent impact of the human malaria parasite Plasmodium falciparum gametocyte sex ratio on mosquito infection rates

Density-dependent impact of the human malaria parasite Plasmodium falciparum gametocyte sex ratio on mosquito infection rates

Mitosis in the Human Malaria Parasite Plasmodium falciparum

Comparative Susceptibilities of Species T and U of theAnopheles fluviatilisComplex toPlasmodium vinckei petteriSporogony

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