scholarly journals Adaptive periodicity in the infectivity of malaria gametocytes to mosquitoes

2018 ◽  
Author(s):  
Petra Schneider ◽  
Samuel S. C. Rund ◽  
Natasha L. Smith ◽  
Kimberley F. Prior ◽  
Aidan J. O’Donnell ◽  
...  
Keyword(s):  
Blood Feeding ◽  
Blood Parasite ◽  
Parasite Development ◽  
Bed Nets ◽  
Mosquito Vectors ◽  
Plasmodium Chabaudi ◽  
Malaria Parasites ◽  
Rodent Malaria

AbstractThat periodicity in the biting activity of mosquito vectors explains why malaria parasites have evolved rhythms in cycles of asexual replication in the host’s blood was proposed almost 50 years ago. Yet, tests of this hypothesis have proved inconclusive. Using the rodent malaria Plasmodium chabaudi, we examine rhythms in the density and infectivity of transmission forms (gametocytes) in the host’s blood, parasite development inside mosquitoes, and onwards transmission.Moreover, we control for the confounding effects of rhythms in mosquito susceptibility. We reveal that at night, gametocytes are twice as infective to mosquitoes, despite being less numerous in the blood. This enhanced infectiousness at night interacts with mosquito rhythms to increase sporozoite burdens by almost four-fold when mosquitoes feed during their day. Thus, daytime blood-feeding (e.g. driven by the use of bed nets) may render gametocytes less infective, but this is compensated for by the greater susceptibility of mosquitoes.

scholarly journals Adaptive periodicity in the infectivity of malaria gametocytes to mosquitoes

2018 ◽  
Vol 285 (1888) ◽  
pp. 20181876 ◽  
Author(s):  
Petra Schneider ◽  
Samuel S. C. Rund ◽  
Natasha L. Smith ◽  
Kimberley F. Prior ◽  
Aidan J. O'Donnell ◽  
...  
Keyword(s):  
Blood Parasite ◽  
Parasite Development ◽  
Bed Nets ◽  
Immune Defence ◽  
Mosquito Vectors ◽  
Molecular Processes ◽  
Daily Rhythms ◽  
The Earth ◽  
Rotation Of The Earth ◽  
Biting Time

Daily rhythms in behaviour, physiology and molecular processes are expected to enable organisms to appropriately schedule activities according to consequences of the daily rotation of the Earth. For parasites, this includes capitalizing on periodicity in transmission opportunities and for hosts/vectors, this may select for rhythms in immune defence. We examine rhythms in the density and infectivity of transmission forms (gametocytes) of rodent malaria parasites in the host's blood, parasite development inside mosquito vectors and potential for onwards transmission. Furthermore, we simultaneously test whether mosquitoes exhibit rhythms in susceptibility. We reveal that at night, gametocytes are twice as infective, despite being less numerous in the blood. Enhanced infectiousness at night interacts with mosquito rhythms to increase sporozoite burdens fourfold when mosquitoes feed during their rest phase. Thus, changes in mosquito biting time (owing to bed nets) may render gametocytes less infective, but this is compensated for by the greater mosquito susceptibility.

scholarly journals Ex VivoMaturation Assay for Testing Antimalarial Sensitivity of Rodent Malaria Parasites

2016 ◽  
Vol 60 (11) ◽  
pp. 6859-6866 ◽  
Author(s):  
Zi Wei Chang ◽  
Benoit Malleret ◽  
Bruce Russell ◽  
Laurent Rénia ◽  
Carla Claser
Keyword(s):  
Ex Vivo ◽  
Single Step ◽  
Parasite Development ◽  
Ring Stage ◽  
Malaria Parasites ◽  
Rodent Malaria ◽  
Content Type ◽  
Parasite Biology

ABSTRACTEx vivoassay systems provide a powerful approach to studying human malaria parasite biology and to testing antimalarials. For rodent malaria parasites, short-termin vitroculture andex vivoantimalarial susceptibility assays are relatively cumbersome, relying onin vivopassage for synchronization, since ring-stage parasites are an essential starting material. Here, we describe a new approach based on the enrichment of ring-stagePlasmodium berghei,P. yoelii, andP. vinckei vinckeiusing a single-step Percoll gradient. Importantly, we demonstrate that the enriched ring-stage parasites develop synchronously regardless of the parasite strain or species used. Using a flow cytometry assay with Hoechst and ethidium or MitoTracker dye, we show that parasite development is easily and rapidly monitored. Finally, we demonstrate that this approach can be used to screen antimalarial drugs.

scholarly journals Disruption of the coordination between host circadian rhythms and malaria parasite development alters the duration of the intraerythrocytic cycle

2019 ◽  
Author(s):  
Amit K. Subudhi ◽  
Aidan J. O’Donnell ◽  
Abhinay Ramaprasad ◽  
Hussein M. Abkallo ◽  
Abhinav Kaushik ◽  
...  
Keyword(s):  
Parasite Development ◽  
Developmental Cycle ◽  
Plasmodium Chabaudi ◽  
Malaria Parasites ◽  
Multiple Processes ◽  
Free Running ◽  
Fitness Benefits ◽  
Circadian Transcription

Malaria parasites complete their intra-erythrocytic developmental cycle (IDC) in multiples of 24 hours (depending on the species), suggesting a circadian basis to the asexual cell cycle, but the mechanism controlling this periodicity is unknown. Combining in vivo and in vitro approaches using rodent and human malaria parasites, we reveal that: (i) 57% of Plasmodium chabaudi genes exhibit 24 h “circadian” periodicity in transcription; (ii) 58% of these genes lose transcriptional rhythmicity when the IDC is out-of-synchrony with host rhythms; (iii) 9% of Plasmodium falciparum genes show circadian transcription under free-running conditions; (iv) Serpentine receptor 10 (SR10) has a circadian transcription profile and disrupting it in rodent malaria parasites shortens the IDC by 2-3 hours; (v) Multiple processes including DNA replication and the ubiquitin and proteasome pathways are affected by loss of coordination with host rhythms and by disruption of SR10. Our results show that malaria parasites are at least partly responsible for scheduling their IDCs explaining the fitness benefits of coordination with host rhythms.

scholarly journals Rodent malaria parasites Plasmodium chabaudi and P. vinckei do not increase their rates of gametocytogenesis in response to mosquito probing

2005 ◽  
Vol 272 (1579) ◽  
pp. 2397-2402 ◽  
Author(s):  
Dave Shutler ◽  
Sarah E Reece ◽  
Adele Mullie ◽  
Peter F Billingsley ◽  
Andrew F Read
Keyword(s):  
Plasmodium Chabaudi ◽  
Malaria Parasites ◽  
Rodent Malaria

scholarly journals The influence of feeding behaviour and temperature on the capacity of mosquitoes to transmit malaria

2019 ◽  
Author(s):  
Eunho Suh ◽  
Marissa K. Grossman ◽  
Jessica L. Waite ◽  
Nina L. Dennington ◽  
Ellie Sherrard-Smith ◽  
...  
Keyword(s):  
Feeding Behaviour ◽  
Vector Competence ◽  
Thermal Sensitivity ◽  
Blood Feeding ◽  
Malaria Vectors ◽  
Parasite Development ◽  
Bed Nets ◽  
Behavioural Resistance ◽  
Epidemiological Impact ◽  
Insecticide Treated Bed Nets

AbstractInsecticide-treated bed nets reduce malaria transmission by limiting contact between mosquito vectors and human hosts when mosquitoes feed during the night. However, malaria vectors can also feed in the early evening and in the morning when people are not protected. Here, we explored how timing of blood feeding interacts with environmental temperature to influence the capacity of Anopheles mosquitoes to transmit the human malaria parasite, Plasmodium falciparum. We found no effect of biting time itself on the proportion of mosquitoes that became infectious (vector competence) at constant temperature. However, when mosquitoes were maintained under more realistic fluctuating temperatures there was a significant increase in competence for mosquitoes feeding in the evening, and a significant reduction in competence for those feeding in the morning, relative to those feeding at midnight. These effects appear to be due to thermal sensitivity of malaria parasites during the initial stages of parasite development within the mosquito, and the fact that mosquitoes feeding in the evening experience cooling temperatures during the night, whereas mosquitoes feeding in the morning quickly experience warming temperatures that are inhibitory to parasite establishment. A transmission dynamics model illustrates that such differences in competence could have important implications for disease endemicity, the extent of transmission that persists in the presence of bed nets, and the epidemiological impact of behavioural resistance. These results indicate the interaction of temperature and feeding behaviour to be a major ecological determinant of the vectorial capacity of malaria mosquitoes.

scholarly journals Sex ratios in the rodent malaria parasite, Plasmodium chabaudi

Parasitology ◽  
2003 ◽  
Vol 127 (5) ◽  
pp. 419-425 ◽  
Author(s):  
S. E. REECE ◽  
A. B. DUNCAN ◽  
S. A. WEST ◽  
A. F. READ
Keyword(s):  
Mortality Rate ◽  
Sex Ratio ◽  
Malaria Parasite ◽  
Sex Ratios ◽  
Plasmodium Chabaudi ◽  
Rodent Malaria Parasite ◽  
Malaria Parasites ◽  
Rodent Malaria ◽  
Sex Ratio Theory

The sex ratios of malaria and related Apicomplexan parasites play a major role in transmission success. Here, we address 2 fundamental issues in the sex ratios of the rodent malaria parasite, Plasmodium chabaudi. First we test the accuracy of empirical methods for estimating sex ratios in malaria parasites, and show that sex ratios made with standard thin smears may overestimate the proportion of female gametocytes. Secondly, we test whether the mortality rate differs between male and female gametocytes, as assumed by sex ratio theory. Conventional application of sex ratio theory to malaria parasites assumes that the primary sex ratio can be accurately determined from mature gametocytes circulating in the peripheral circulation. We stopped gametocyte production with chloroquine in order to study a cohort of gametocytes in vitro. The mortality rate was significantly higher for female gametocytes, with an average half-life of 8 h for female gametocytes and 16 h for male gametocytes.

scholarly journals Mosquito vector proteins homologous to α1-3 galactosyl transferases of tick vectors in the context of protective immunity against malaria and hypersensitivity to vector bites

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ranjan Ramasamy
Keyword(s):  
Anopheles Gambiae ◽  
De Novo ◽  
Ixodes Scapularis ◽  
Blood Feeding ◽  
New World Monkeys ◽  
Mosquito Vector ◽  
Mosquito Vectors ◽  
Malaria Parasites ◽  
Tick Vector ◽  
Galactosyl Transferase

Abstract Background An epitope, Galα1-3Galβ1-4GlcNAc-R, termed α-gal, is present in glycoconjugates of New World monkeys (platyrrhines) and other mammals but not in hominoids and Old World monkeys (catarrhines). The difference is due to the inactivation of α1-3 galactosyl transferase (α1-3 GT) genes in catarrhines. Natural antibodies to α-gal are therefore developed in catarrhines but not platyrrhines and other mammals. Hypersensitivity reactions are commonly elicited by mosquito and tick vector bites. IgE antibodies against α-gal cause food allergy to red meat in persons who have been exposed to tick bites. Three enzymes synthesising the terminal α1-3-linked galactose in α-gal, that are homologous to mammalian α and β1-4 GTs but not mammalian α1-3 GTs, were recently identified in the tick vector Ixodes scapularis. IgG and IgM antibodies to α-gal are reported to protect against malaria because mosquito-derived sporozoites of malaria parasites express α-gal on their surface. This article explores the possibility that the α-gal in sporozoites are acquired from glycoconjugates synthesised by mosquitoes rather than through de novo synthesis by sporozoites. Methods The presence of proteins homologous to the three identified tick α1-3 GTs and mammalian α1-3 GTs in two important mosquito vectors, Aedes aegypti and Anopheles gambiae, as well as Plasmodium malaria parasites, was investigated by BLASTp analysis to help clarify the source of the α-gal on sporozoite surfaces. Results Anopheles gambiae and Ae. aegypti possessed several different proteins homologous to the three I. scapularis proteins with α1-3 GT activity, but not mammalian α1-3 GTs. The putative mosquito α1-3 GTs possessed conserved protein domains characteristic of glycosyl transferases. However, the genus Plasmodium lacked proteins homologous to the three I. scapularis proteins with α1-3 GT activity and mammalian α1-3 GTs. Conclusions The putative α1-3 GTs identified in the two mosquito vectors may synthesise glycoconjugates containing α-gal that can be transferred to sporozoite surfaces before they are inoculated into skin during blood feeding. The findings merit further investigation because of their implications for immunity against malaria, hypersensitivity to mosquito bites, primate evolution, and proposals for immunisation against α-gal. Graphic abstract

scholarly journals A cornucopia of research resources for the fourth rodent malaria parasite species

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jane M. Carlton
Keyword(s):  
Malaria Parasite ◽  
Parasite Species ◽  
First Century ◽  
Model Systems ◽  
Rodent Malaria Parasite ◽  
Malaria Parasites ◽  
Rodent Malaria ◽  
Human Malaria ◽  
Plasmodium Vinckei ◽  
Research Resources

AbstractThe study of human malaria caused by species of Plasmodium has undoubtedly been enriched by the use of model systems, such as the rodent malaria parasites originally isolated from African thicket rats. A significant gap in the arsenal of resources of the species that make up the rodent malaria parasites has been the lack of any such tools for the fourth of the species, Plasmodium vinckei. This has recently been rectified by Abhinay Ramaprasad and colleagues, whose pivotal paper published in BMC Biology describes a cornucopia of new P. vinckei ‘omics datasets, mosquito transmission experiments, transfection protocols, and virulence phenotypes, to propel this species firmly into the twenty-first century.

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