BACKGROUND In Plasmodium, meiosis occurs in diploid zygotes as they develop into haploid motile ookinetes inside the mosquito. Further sporogonic development involves transformation of ookinetes into oocysts and formation of infective sporozoites. METHODOLOGY/PRINCIPAL FINDINGS Reverse genetics was employed to examine the role of the meiotic specific recombinase Dmc1, a bacterial RecA homolog...

One of the most important unanswered questions in evolutionary biology is why sexual reproduction is so common. In theory, sex is so costly that individuals that reproduce sexually should be at a major disadvantage relative to asexually reproducing competitors. This leads to the expectation that sex should lose in competition with asexual reproduction and thus be rare in nature, which is in str...

Despite the severe fitness costs associated with sexual reproduction, its persistence and pervasiveness among multicellular organisms testifies to its intrinsic, short-term advantages. However, the reproductive assurance hypothesis predicts selection favoring asexual reproduction in sparse populations and when mate finding is difficult. Difficulties in finding mates is especially common in para...

The study of the development of malaria Parasites in infected birds and men (and later lnanimals) has now been going on for oyer SO years. The phase in the red cells, including p sexual and asexual forms, seems fairly ?*ear, but it has always been uncertain what happens to the sporozoites injected by the Mosquito before the forms in the red cells aPpear, and also it has been surmised that Paras...

Abstract Background In the absence of a method to culture Plasmodium vivax , only way source parasites is ex vivo. This hampers many aspects P. research. study aimed assess safety apheresis, for selective removal specific components blood as means extracting and concentrating parasites. Methods An iterative approach was employed across four non-immune healthy human subjects in single subject co...

Protective immunizat ion of the vertebrate host against malar ia can operate against either of two distinct stages of the parasite's life cycle. The sporozoite forms, which develop in the salivary glands of the infected mosquito, are immunogenic in the vertebrate host (1) and possess a major surface antigen against which a protective immune response can be elicited (2, 3). The asexual blood sta...

Protective immunizat ion of the vertebrate host against malar ia can operate against either of two distinct stages of the parasite's life cycle. The sporozoite forms, which develop in the salivary glands of the infected mosquito, are immunogenic in the vertebrate host (1) and possess a major surface antigen against which a protective immune response can be elicited (2, 3). The asexual blood sta...

BACKGROUND Whole malaria parasites are highly effective in inducing immunity against malaria. Due to the limited success of subunit based vaccines in clinical studies, there has been a renewed interest in whole parasite-based malaria vaccines. Apart from attenuated sporozoites, there have also been efforts to use live asexual stage parasites as vaccine immunogens. METHODOLOGY AND RESULTS We u...

When hosts experience environmental stress, the quantity and quality of resources they provide for parasites may be diminished, and host longevity may be decreased. Under stress, parasites may adopt alternative strategies to avoid fitness reductions. Trematode parasites typically have complex life cycles, involving asexual reproduction in a gastropod first intermediate host. A rare phenomenon, ...

Polyamines and the enzymes involved in their biosynthesis are present at high levels in rapidly proliferating cells, including cancer cells and protozoan parasites. Inhibition of polyamine biosynthesis in asexual blood-stage malaria parasites causes cytostatic arrest of parasite development under in vitro conditions, but does not cure infections in vivo. This may be due to replenishment of the ...