scholarly journals Molecular mechanisms of fertilization and development of malaria parasites in mosquito vectors

2018 ◽  
Vol 69 (3) ◽  
pp. 153-154
Author(s):  
Tomoko Ishino ◽  
Mayumi Tachibana ◽  
Eizo Takashima ◽  
Takafumi Tsuboi ◽  
Motomi Torii
Keyword(s):  
Molecular Mechanisms ◽  
Mosquito Vectors ◽  
Malaria Parasites

Avian Malaria Parasites Share Congeneric Mosquito Vectors

2010 ◽  
Vol 96 (1) ◽  
pp. 144-151 ◽  
Author(s):  
M. Kimura ◽  
J. M. Darbro ◽  
L. C. Harrington
Keyword(s):  
Avian Malaria ◽  
Mosquito Vectors ◽  
Malaria Parasites ◽  
Avian Malaria Parasites

scholarly journals Transcriptional variation in malaria parasites: why and how

2019 ◽  
Vol 18 (5) ◽  
pp. 329-341 ◽  
Author(s):  
Oriol Llorà-Batlle ◽  
Elisabet Tintó-Font ◽  
Alfred Cortés
Keyword(s):  
Molecular Mechanisms ◽  
Transcriptional Responses ◽  
Malaria Parasites ◽  
Genetic Changes ◽  
Alternative Phenotypes ◽  
Transcriptional Variation ◽  
Parasite Survival ◽  
Transcriptional Changes ◽  
Stochastic Events ◽  
Parasite Populations

Abstract Transcriptional differences enable the generation of alternative phenotypes from the same genome. In malaria parasites, transcriptional plasticity plays a major role in the process of adaptation to fluctuations in the environment. Multiple studies with culture-adapted parasites and field isolates are starting to unravel the different transcriptional alternatives available to Plasmodium falciparum and the underlying molecular mechanisms. Here we discuss how epigenetic variation, directed transcriptional responses and also genetic changes that affect transcript levels can all contribute to transcriptional variation and, ultimately, parasite survival. Some transcriptional changes are driven by stochastic events. These changes can occur spontaneously, resulting in heterogeneity within parasite populations that provides the grounds for adaptation by dynamic natural selection. However, transcriptional changes can also occur in response to external cues. A better understanding of the mechanisms that the parasite has evolved to alter its transcriptome may ultimately contribute to the design of strategies to combat malaria to which the parasite cannot adapt.

scholarly journals Can malaria parasites manipulate the odour-mediated host preference of their mosquito vectors?

2017 ◽  
Author(s):  
Phuong L. Nguyen ◽  
Amélie Vantaux ◽  
Domonbabele FdS Hien ◽  
Kounbobr R. Dabiré ◽  
Bienvenue K. Yameogo ◽  
...  
Keyword(s):  
Mosquito Species ◽  
Host Choice ◽  
Host Feeding ◽  
Parasite Transmission ◽  
Mosquito Vectors ◽  
Outdoor Air ◽  
Malaria Parasites ◽  
Activation Rate ◽  
Human Odour ◽  
Feeding Behaviours

AbstractMalaria parasites can manipulate mosquito feeding behaviours such as motivation and avidity to feed on vertebrate hosts in ways that increase parasite transmission. However, in natural conditions, not all vertebrate blood-sources are suitable hosts for the parasite. Whether malaria parasites can manipulate mosquito host choice in ways that enhance parasite transmission toward suitable hosts and/or reduce mosquito attraction to unsuitable hosts (i.e. specific manipulation) is unknown. To address this question, we experimentally infected three species of mosquito vectors (Anopheles coluzzii, Anopheles gambiae, and Anopheles arabiensis) with wild isolates of the human malaria parasite Plasmodium falciparum, and examined the effects of immature (oocyst) and mature (sporozoite) infections on mosquito behavioural responses (activation rate and odour choice) to combinations of calf odour, human odour and outdoor air using a dual-port olfactometer. Regardless of parasite developmental stage and mosquito species, P. falciparum infection did not alter mosquito activation rate or their choice for human odours. The overall expression pattern of host choice of all three mosquito species was consistent with a high degree of anthropophily, with both infected and uninfected individuals showing higher attraction toward human odour over calf odour, human odour over outdoor air, and outdoor air over calf odour. Our results suggests that, in this system, the parasite may not be able to manipulate the early long-range behavioural steps involved in the mosquito host-feeding process, including initiation of host-seeking and host orientation. Future studies examining mosquito host-feeding behaviours at a shorter range (i.e. the “at-host” foraging activities) are required to test whether malaria parasites can modify their mosquito host choice to enhance transmission toward suitable hosts and/or reduce biting on unsuitable hosts.

scholarly journals Combination Therapy Counteracts the Enhanced Transmission of Drug-Resistant Malaria Parasites to Mosquitoes

2004 ◽  
Vol 48 (10) ◽  
pp. 3940-3943 ◽  
Author(s):  
Rachel L. Hallett ◽  
Colin J. Sutherland ◽  
Neal Alexander ◽  
Rosalynn Ord ◽  
Musa Jawara ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Selective Advantage ◽  
Treated Group ◽  
Sub Saharan Africa ◽  
Drug Resistant ◽  
Mosquito Vectors ◽  
Malaria Parasites ◽  
Enhanced Transmission ◽  
Sub Saharan ◽  
The Impact

ABSTRACT Malaria parasites carrying genes conferring resistance to antimalarials are thought to have a selective advantage which leads to higher rates of transmissibility from the drug-treated host. This is a likely mechanism for the increasing prevalence of parasites with resistance to chloroquine (CQ) and sulfadoxine-pyrimethamine in sub-Saharan Africa. Combination therapy is the key strategy being implemented to reduce the impact of resistance, but its effect on the transmission of genetically resistant parasites from treated patients to mosquito vectors has not been measured directly. In a trial comparing CQ monotherapy to the combination CQ plus artesunate (AS) in Gambian children with uncomplicated falciparum malaria, we measured transmissibility by feeding Anopheles gambiae mosquitoes with blood from 43 gametocyte-positive patients through a membrane. In the CQ-treated group, gametocytes from patients carrying parasites with the CQ resistance-associated allele pfcrt-76T prior to treatment produced infected mosquitoes with 38 times higher Plasmodium falciparum oocyst burdens than mosquitoes fed on gametocytes from patients infected with sensitive parasites (P < 0.001). Gametocytes from parasites carrying the resistance-associated allele pfmdr1-86Y produced 14-fold higher oocyst burdens than gametocytes from patients infected with sensitive parasites (P = 0.011). However, parasites carrying either of these resistance-associated alleles pretreatment were not associated with higher mosquito oocyst burdens in the CQ-AS-treated group. Thus, combination therapy overcomes the transmission advantage enjoyed by drug-resistant parasites.

scholarly journals Optimization of CRISPR/Cas System for Improving Genome Editing Efficiency in Plasmodium falciparum

2021 ◽  
Vol 11 ◽  
Author(s):  
Yuemeng Zhao ◽  
Fei Wang ◽  
Changhong Wang ◽  
Xiaobai Zhang ◽  
Cizhong Jiang ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Genome Editing ◽  
Gene Editing ◽  
Molecular Mechanisms ◽  
Related Gene ◽  
Malaria Parasites ◽  
Human Malaria Parasite ◽  
Genome Feature ◽  
First Time ◽  
Transgenic Strains

Studies of molecular mechanisms and related gene functions have long been restricted by limited genome editing technologies in malaria parasites. Recently, a simple and effective genome editing technology, the CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated) system, has greatly facilitated these studies in many organisms, including malaria parasites. However, due to the special genome feature of malaria parasites, the manipulation and gene editing efficacy of the CRISPR/Cas system in this pathogen need to be improved, particularly in the human malaria parasite, Plasmodium falciparum. Herein, based on the CRISPR/Cas9 system, we developed an integrating strategy to generate a Cas9i system, which significantly shortened the time for generation of transgenic strains in P. falciparum. Moreover, with this Cas9i system, we have successfully achieved multiplexed genome editing (mutating or tagging) by a single-round transfection in P. falciparum. In addition, we for the first time adapted AsCpf1 (Acidaminococcus sp. Cpf1), an alternative to Cas9, into P. falciparum parasites and examined it for gene editing. These optimizations of the CRISPR/Cas system will further facilitate the mechanistic research of malaria parasites and contribute to eliminating malaria in the future.

scholarly journals Targeting SUMOylation in Plasmodium as a Potential Target for Malaria Therapy

2021 ◽  
Vol 11 ◽  
Author(s):  
Daffiny Sumam de Oliveira ◽  
Thales Kronenberger ◽  
Giuseppe Palmisano ◽  
Carsten Wrenger ◽  
Edmarcia Elisa de Souza
Keyword(s):  
Life Cycle ◽  
Molecular Mechanisms ◽  
Gene Expression Regulation ◽  
Public Health Problem ◽  
Complex Life Cycle ◽  
Cellular Functions ◽  
Cellular Mechanisms ◽  
Malaria Parasites ◽  
Malaria Therapy ◽  
Lysine Residues

Malaria is a parasitic disease that represents a public health problem worldwide. Protozoans of the Plasmodium genus are responsible for causing malaria in humans. Plasmodium species have a complex life cycle that requires post-translational modifications (PTMs) to control cellular activities temporally and spatially and regulate the levels of critical proteins and cellular mechanisms for maintaining an efficient infection and immune evasion. SUMOylation is a PTM formed by the covalent linkage of a small ubiquitin-like modifier protein to the lysine residues on the protein substrate. This PTM is reversible and is triggered by the sequential action of three enzymes: E1-activating, E2-conjugating, and E3 ligase. On the other end, ubiquitin-like-protein-specific proteases in yeast and sentrin-specific proteases in mammals are responsible for processing SUMO peptides and for deconjugating SUMOylated moieties. Further studies are necessary to comprehend the molecular mechanisms and cellular functions of SUMO in Plasmodium. The emergence of drug-resistant malaria parasites prompts the discovery of new targets and antimalarial drugs with novel mechanisms of action. In this scenario, the conserved biological processes regulated by SUMOylation in the malaria parasites such as gene expression regulation, oxidative stress response, ubiquitylation, and proteasome pathways, suggest PfSUMO as a new potential drug target. This mini-review focuses on the current understanding of the mechanism of action of the PfSUMO during the coordinated multi-step life cycle of Plasmodium and discusses them as attractive new target proteins for the development of parasite-specific inhibitors and therapeutic intervention toward malaria disease.

scholarly journals Regulation of Sexual Commitment and Gametocytogenesis in Malaria Parasites

2018 ◽  
Vol 72 (1) ◽  
pp. 501-519 ◽  
Author(s):  
Gabrielle A. Josling ◽  
Kim C. Williamson ◽  
Manuel Llinás
Keyword(s):  
Sexual Development ◽  
Sexual Differentiation ◽  
Molecular Mechanisms ◽  
Therapeutic Interventions ◽  
Malaria Parasites ◽  
Asexual Blood Stage ◽  
The Subject ◽  
Epigenetic Regulators ◽  
Better Than ◽  
Made In

Sexual differentiation of malaria parasites from the asexual blood stage into gametocytes is an essential part of the life cycle, as gametocytes are the form that is taken up by the mosquito host. Because of the essentiality of this process for transmission to the mosquito, gametocytogenesis is an extremely attractive target for therapeutic interventions. The subject of this review is the considerable progress that has been made in recent years in elucidating the molecular mechanisms governing this important differentiation process. In particular, a number of critical transcription factors and epigenetic regulators have emerged as crucial elements in the regulation of commitment. The identification of these factors has allowed us to understand better than ever before the events occurring prior to and during commitment to sexual development and offers potential for new therapeutic interventions.

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.

Sign in / Sign up

Export Citation Format

Share Document