Highly efficient subcloning of rodent malaria parasites by injection of single merosomes or detached cells

Stanway, Rebecca Limenitakis; Graewe, Stefanie; Rennenberg, Annika; Helm, Susanne; Heussler, Volker

doi:10.1038/nprot.2009.172

Cited by 15 publications

(18 citation statements)

References 26 publications

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“…They appeared to move more freely and much faster (Video S2). This rapid movement of merozoites also served as a marker of parasite viability, as injection of detached cells or merosomes containing motile merozoites into mice reproducibly led to blood stage infections [8]. In summary, since the PVM disintegrates entirely before and during detachment of the host cell, it also can be dismissed as the origin of the detached cell and merosome membrane.…”

Section: Resultsmentioning

confidence: 97%

“…First, merozoites in the resulting detached cells moved rapidly (compare Video S4). This rapid movement is a marker of parasite viability since injection of illuminated detached cells and merosomes containing motile merozoites into mice consistently results in blood stage infection [8]. Interestingly, the movement of merozoites appears to become far more pronounced once the PVM has ruptured, indicating that active movement was constrained by the PVM barrier.…”

Section: Discussionmentioning

confidence: 99%

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Hostile Takeover by Plasmodium: Reorganization of Parasite and Host Cell Membranes during Liver Stage Egress

et al. 2011

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The protozoan parasite Plasmodium is transmitted by female Anopheles mosquitoes and undergoes obligatory development within a parasitophorous vacuole in hepatocytes before it is released into the bloodstream. The transition to the blood stage was previously shown to involve the packaging of exoerythrocytic merozoites into membrane-surrounded vesicles, called merosomes, which are delivered directly into liver sinusoids. However, it was unclear whether the membrane of these merosomes was derived from the parasite membrane, the parasitophorous vacuole membrane or the host cell membrane. This knowledge is required to determine how phagocytes will be directed against merosomes. Here, we fluorescently label the candidate membranes and use live cell imaging to show that the merosome membrane derives from the host cell membrane. We also demonstrate that proteins in the host cell membrane are lost during merozoite liberation from the parasitophorous vacuole. Immediately after the breakdown of the parasitophorous vacuole membrane, the host cell mitochondria begin to degenerate and protein biosynthesis arrests. The intact host cell plasma membrane surrounding merosomes allows Plasmodium to mask itself from the host immune system and bypass the numerous Kupffer cells on its way into the bloodstream. This represents an effective strategy for evading host defenses before establishing a blood stage infection.

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Section: Resultsmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Hostile Takeover by Plasmodium: Reorganization of Parasite and Host Cell Membranes during Liver Stage Egress

et al. 2011

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“…Single detached cells were injected into mice for direct cloning [36] and the clone obtained was named PbICP KO . Similar to previous work [31], these PbICP-deficient parasites could establish a blood stage infection.…”

Section: Resultsmentioning

confidence: 99%

“…The transgenic PbICP cond parasite line was cloned by injection of a single infected detached hepatocyte or merosome into mice, as previously described [36]. Briefly, HepG2 cells were infected with PbICP cond sporozoites and the resulting detached infected hepatocytes were collected 65 hours later.…”

Section: Methodsmentioning

confidence: 99%

A Cysteine Protease Inhibitor of Plasmodium berghei Is Essential for Exo-erythrocytic Development

et al. 2014

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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.

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“…These stages are not hypnozoites. The question arises as to whether some malarial "merosomes" (Sturm et al 2006;Baer et al 2007;Stanway et al 2009) persist as merophores.…”

Section: Non-hypnozoite-associated Dormancy In Mammalian Malariamentioning

confidence: 99%

The hypnozoite concept, with particular reference to malaria

Markus

2010

Parasitol Res

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In 1978, the nature of the hypnozoite was discussed in an article that appeared in a relatively obscure journal, which is also where the term was adopted for Plasmodium (a little-known fact). As a result, that commentary on the use of the word "hypnozoite" has been almost completely overlooked. Although the publication is now more than three decades old, the analysis remains valid today. It is explained in the present paper that like "merozoite" and "sporozoite", the name "hypnozoite" is applicable not only to a latent stage in the life cycle of Plasmodium but to some apparently dormant forms of other kinds of apicomplexan parasites as well. Merozoites of different genera of parasitic protozoa are not necessarily the same biologically and/or otherwise. Similarly, although the hypnozoite concept relates primarily to pre-merozoite stages, some atypical post-divisional apicomplexan forms might also be hypnozoites. Examples are likewise given of latent organisms that, in contrast, are clearly not hypnozoites, such as dormant merozoites in malaria infections. Lastly, the plasmodial hypnozoite is placed in context in relation to the relatively unfamiliar (nomenclaturally) malarial bradysporozoite, chronozoite, dormozoite, merophore, merosome and x body. This paper is based on a presentation by the author, as a Life Member of the American Society of Tropical Medicine and Hygiene, to its 59th Annual Meeting in Atlanta, Georgia, USA, 3-7 November 2010.

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Highly efficient subcloning of rodent malaria parasites by injection of single merosomes or detached cells

Cited by 15 publications

References 26 publications

Hostile Takeover by Plasmodium: Reorganization of Parasite and Host Cell Membranes during Liver Stage Egress

Hostile Takeover by Plasmodium: Reorganization of Parasite and Host Cell Membranes during Liver Stage Egress

A Cysteine Protease Inhibitor of Plasmodium berghei Is Essential for Exo-erythrocytic Development

The hypnozoite concept, with particular reference to malaria

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