Cell cycle analysis of asexual stages of erythrocytic malaria parasites

Jacobberger, James W.; Horan, Paul K.; Hare, J.D.

doi:10.1111/j.1365-2184.1992.tb01452.x

Cited by 27 publications

(25 citation statements)

References 30 publications

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“…These characteristics make its utilization in malaria drug discovery an important advantage in terms of cost effectiveness and it has already been successfully used for testing human samples (32). However, its application has remained problematic in murine models of malaria due to the presence of a relatively high percentage of erythrocytes that contain significant amounts of nucleic acids (2,6,33). An interesting alternative could be the use of green fluorescent protein-transformed plasmodia, as recently described for P. berghei (34).…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, as suggested by Jacobberger et al (6), Howell-Jolly bodies might establish a limit to sensitivity and specificity. This technical difficulty for measurement of parasitemias in murine models of malaria decreases sensitivity to 0.1% to 0.2% under the best conditions (2).…”

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confidence: 99%

“…Because infected erythrocytes contain nucleic acids from the different stages of Plasmodium, the former can be easily identified and counted by flow cytometry using DNA staining dyes. Among these, Hoescht 33258 and Hoescht 33342 are able to cross cellular membranes and are specific for DNA (3)(4)(5)(6). However, they require flow cytometers equipped with ultraviolet lasers that are not available in most laboratories.…”

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confidence: 99%

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Improvement of detection specificity of Plasmodium‐infected murine erythrocytes by flow cytometry using autofluorescence and YOYO‐1

et al. 2005

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Background: Microscopic analysis of blood smears is currently the most frequently used method to measure parasitemias in experiments of drug efficacy in murine models of malaria. However, it is subjective and labour intensive, which preclude its utilization in large-scale evaluation programs. Flow cytometry is an alternative method, but due to the limited specificity achieved with the currently available techniques, it has not been widely used in murine models of malaria during preclinical evaluation. We describe a new flow cytometric method based on the differences of autofluorescence and DNA content measured after staining with YOYO-1 that are observed in infected erythrocytes compared with noninfected erythrocytes. Methods: Samples of blood from Plasmodium yoeliiinfected animals were fixed with glutaraldehyde, incubated with RNAase, and stained with YOYO-1 in 96-well plate format. After acquisition, erythrocytes gated in loga-

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Improvement of detection specificity of Plasmodium‐infected murine erythrocytes by flow cytometry using autofluorescence and YOYO‐1

et al. 2005

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“…However, several aspects remain poorly understood, particularly in connection with the G2 and M phases [8,9]. In the present study we demonstrate the stage-specific antimalarial activity of simaomicin a , although the mechanism of action remains unresolved.…”

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confidence: 59%

“…is as follows. G0-like phase is a merozoite (both free and late segmenters) form; G1 phase is an early trophozoite stage; S phase is soon after the appearance of pigmented trophozoites (this phase is considered as the trophozoite stage in this experiment); M phase is after the first nuclear division (this is considered as the schizont stage in this experiment); and the G2 phase, which is still unclear [8,9]. Naughton and Bell reported that drugs such as Hoechst 33342, roscovitine and L-mimosine blocked the trophozoite-schizont boundary, presumably in the S or G2 phase.…”

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Simaomicin α: Effects on the Cell Cycle of Synchronized, Cultured Plasmodium falciparum

et al. 2008

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Simaomicin a shows potent antimalarial activity in vitro and is known to be a cell-cycle effector. As erythrocytic schizogony of Plasmodium correlates with cell cycle events, we investigated the effect of simaomicin a on stage development of the malaria parasite Plasmodium falciparum. Simaomicin a interferes with normal parasite development in a time and concentration dependent manner. Parasites exposed to 2.5 nM simaomicin a at the ring stage or trophozoite stage showed disrupted development and immature schizont-like and segmenterlike forms were observed. However, schizont stage parasites were not affected by 2.5 nM simaomicin a. It is unclear whether mitosis involved in sequential parasite development occurred when parasites were exposed to simaomicin a at the ring or trophozoite stage. At a concentration of 5.0 nM, simaomicin a inhibited merozoite-trophozoite development. This concentration curtails p-LDH activity at all parasite stages, although its impact on the schizont stage is delayed for 24 hours.Keywords Simaomicin a , Plasmodium, malaria, cellcycle, synchronous culture During the course of our long-term and continuing programme of screening microbial metabolites, we have discovered various compounds that exhibit potent antimalarial activities [1ϳ6]. We previously reported that simaomicin a showed potent antimalarial activity in vitro [6]. Furthermore, we reported that it has bleomycininduced G2 checkpoint inhibitory activity against human Tcell leukemia-derived Jurkat cells [7].Erythrocytic schizogony of Plasmodium falciparum correlates with specific cell-cycle events, such as G1, S and M phases. However, several aspects remain poorly understood, particularly in connection with the G2 and M phases [8,9]. In the present study we demonstrate the stage-specific antimalarial activity of simaomicin a , although the mechanism of action remains unresolved. Consequently, simaomicin a may be useful in studying the cell-cycle of P. falciparum.The drug-sensitive P. falciparum strain FCR3 was cultured and synchronized using the D-sorbitol method [10] to produce specific parasite stages. At 24ϳ36 hours after the first synchronization, the parasites were synchronized again. At 36 hours after the second synchronization the last synchronization was completed. The cells were treated and then used for experimentation. Two or three D-sorbitol treatments were carried out to prepare ring-stage parasites (Ͼ90%) based on direct observation of parasite growth. For experimental purposes, parasite stages were determined as follows: Ring stage (0ϳ12 hours after last synchronization) which has a ring form; early-trophozoite stage (12ϳ24

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The nuclear genome of apicomplexan parasites

Ajioka

Brooke‐Powell

Wan

2005

Encyclopedia of Genetics, Genomics, Proteomics and Bioinformatics

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The Apicomplexa is a highly diverse phylum of parasitic protists that includes the causative agents of malaria and other important human and animal diseases. These unicellular pathogens have been shaped by a key evolutionary event: the secondary endosymbiosis of a single eukaryotic cell and photosynthetic algae. From this event and subsequent evolution, most species in the phylum retain a single mitochondrion and a plastid‐like organelle known as the apicoplast ( see The organelles of Apicomplexan parasites ). The reduced function of these organelles is mirrored by their highly compact genomes, where genes have been lost or transferred to the nucleus, making the nuclear genome a mosaic of former organellar genes embedded in chromosomal DNA from both endosymbionts. Natural selection on this basic cellular and genetic plan has led to a diversity of parasitic life cycles, each with adaptations that specify host range and mechanisms of transmission. Comparative genomics is beginning to reveal the similarities and differences between member species, enhancing our capability to treat and control the devastating diseases they cause.

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Cell cycle analysis of asexual stages of erythrocytic malaria parasites

Cited by 27 publications

References 30 publications

Improvement of detection specificity of Plasmodium‐infected murine erythrocytes by flow cytometry using autofluorescence and YOYO‐1

Improvement of detection specificity of Plasmodium‐infected murine erythrocytes by flow cytometry using autofluorescence and YOYO‐1

Simaomicin α: Effects on the Cell Cycle of Synchronized, Cultured Plasmodium falciparum

The nuclear genome of apicomplexan parasites

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