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falciparum gametocyte culture

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https://www.readbyqxmd.com/read/29114059/effect-of-naturally-occurring-wolbachia-in-anopheles-gambiae-s-l-mosquitoes-from-mali-on-plasmodium-falciparum-malaria-transmission
#1
Fabio M Gomes, Bretta L Hixson, Miles D W Tyner, Jose Luis Ramirez, Gaspar E Canepa, Thiago Luiz Alves E Silva, Alvaro Molina-Cruz, Moussa Keita, Fouseyni Kane, Boïssé Traoré, Nafomon Sogoba, Carolina Barillas-Mury
A naturally occurring Wolbachia strain (wAnga-Mali) was identified in mosquitoes of the Anopheles gambiae complex collected in the Malian villages of Dangassa and Kenieroba. Phylogenetic analysis of the nucleotide sequence of two 16S rRNA regions showed that wAnga-Mali clusters with Wolbachia strains from supergroup A and has the highest homology to a Wolbachia strain isolated from cat fleas (Ctenocephalides). wAnga-Mali is different from two Wolbachia strains previously reported in A. gambiae from Burkina Faso (wAnga_VK5_STP and wAnga_VK5_3...
November 7, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29094698/single-cell-rna-sequencing-reveals-a-signature-of-sexual-commitment-in-malaria-parasites
#2
Asaf Poran, Christopher Nötzel, Omar Aly, Nuria Mencia-Trinchant, Chantal T Harris, Monica L Guzman, Duane C Hassane, Olivier Elemento, Björn F C Kafsack
Pathogens have to balance transmission with persistence. For Plasmodium falciparum, the most widespread and virulent malaria parasite, persistence within its human host requires continuous asexual replication within red blood cells, while its mosquito-borne transmission depends on intra-erythrocytic differentiation into non-replicating sexual stages called gametocytes. Commitment to either fate is determined during the preceding cell cycle that begins with invasion by a single, asexually committed merozoite and ends, 48 hours later, with a schizont releasing newly formed merozoites, all committed to either continued asexual replication or differentiation into gametocytes...
November 2, 2017: Nature
https://www.readbyqxmd.com/read/28877707/semi-high-throughput-detection-of-plasmodium-falciparum-and-plasmodium-vivax-oocysts-in-mosquitoes-using-bead-beating-followed-by-circumsporozoite-elisa-and-quantitative-pcr
#3
Wouter Graumans, Fitsum G Tadesse, Chiara Andolina, Geert-Jan van Gemert, Karina Teelen, Kjerstin Lanke, Endalamaw Gadisa, Delenasaw Yewhalaw, Marga van de Vegte-Bolmer, Rianne Siebelink-Stoter, Isaïe Reuling, Robert Sauerwein, Teun Bousema
BACKGROUND: The malaria infection status of mosquitoes is commonly determined by microscopic detection of oocysts on the dissected mosquito midgut. This method is labour-intensive, does not allow processing of large numbers of mosquitoes and can be challenging in terms of objective classification of oocysts. Here, a semi-high-throughput bead-beating ELISA method is proposed for detection of the circumsporozoite protein (CSP) followed by confirmation by quantitative PCR (qPCR). METHODS: Cultured Plasmodium falciparum gametocytes were offered to Anopheles stephensi mosquitoes and examined by microscopy...
September 6, 2017: Malaria Journal
https://www.readbyqxmd.com/read/28800735/life-span-of-in-vitro-differentiated-plasmodium-falciparum-gametocytes
#4
Tamirat Gebru, Albert Lalremruata, Peter G Kremsner, Benjamin Mordmüller, Jana Held
BACKGROUND: The sexual stages (gametocytes) of Plasmodium falciparum do not directly contribute to the pathology of malaria but are essential for transmission of the parasite from the human host to the mosquito. Mature gametocytes circulate in infected human blood for several days and their circulation time has been modelled mathematically from data of previous in vivo studies. This is the first time that longevity of gametocytes is studied experimentally in vitro. METHODS: The in vitro longevity of P...
August 11, 2017: Malaria Journal
https://www.readbyqxmd.com/read/28705245/abscisic-acid-induces-a-transient-shift-in-signaling-that-enhances-nf-%C3%AE%C2%BAb-mediated-parasite-killing-in-the-midgut-of-anopheles-stephensi-without-reducing-lifespan-or-fecundity
#5
Elizabeth K K Glennon, Brandi K Torrevillas, Shannon F Morrissey, Jadrian M Ejercito, Shirley Luckhart
BACKGROUND: Abscisic acid (ABA) is naturally present in mammalian blood and circulating levels can be increased by oral supplementation. We showed previously that oral ABA supplementation in a mouse model of Plasmodium yoelii 17XNL infection reduced parasitemia and gametocytemia, spleen and liver pathology, and parasite transmission to the mosquito Anopheles stephensi fed on these mice. Treatment of cultured Plasmodium falciparum with ABA at levels detected in our model had no effects on asexual growth or gametocyte formation in vitro...
July 13, 2017: Parasites & Vectors
https://www.readbyqxmd.com/read/28464929/the-development-of-sexual-stage-malaria-gametocytes-in-a-wave-bioreactor
#6
Corine G Demanga, Jenny W L Eng, Donald L Gardiner, Alison Roth, Alice Butterworth, John H Adams, Katharine R Trenholme, John P Dalton
BACKGROUND: Blocking malaria gametocyte development in RBCs or their fertilization in the mosquito gut can prevent infection of the mosquito vector and passage of disease to the human host. A 'transmission blocking' strategy is a component of future malaria control. However, the lack of robust culture systems for producing large amounts of Plasmodium falciparum gametocytes has limited our understanding of sexual-stage malaria biology and made vaccine or chemotherapeutic discoveries more difficult...
May 2, 2017: Parasites & Vectors
https://www.readbyqxmd.com/read/27821171/comparison-of-molecular-quantification-of-plasmodium-falciparum-gametocytes-by-pfs25-qrt-pcr-and-qt-nasba-in-relation-to-mosquito-infectivity
#7
COMPARATIVE STUDY
Helmi Pett, Bronner P Gonçalves, Alassane Dicko, Issa Nébié, Alfred B Tiono, Kjerstin Lanke, John Bradley, Ingrid Chen, Halimatou Diawara, Almahamoudou Mahamar, Harouna M Soumare, Sekou F Traore, Ibrahima Baber, Sodiomon B Sirima, Robert Sauerwein, Joelle Brown, Roly Gosling, Ingrid Felger, Chris Drakeley, Teun Bousema
BACKGROUND: Quantifying gametocyte densities in natural malaria infections is important to estimate malaria transmission potential. Two molecular methods (Pfs25 mRNA quantitative reverse transcriptase PCR (qRT-PCR) and Pfs25 mRNA quantitative nucleic acid sequence based amplification (QT-NASBA)) are commonly used to determine gametocyte densities in clinical and epidemiological studies and allow gametocyte detection at densities below the microscopic threshold for detection. Here, reproducibility of these measurements and the association between estimated gametocyte densities and mosquito infection rates were compared...
November 8, 2016: Malaria Journal
https://www.readbyqxmd.com/read/27688040/role-of-nf-k%C3%AE-factor-rel2-during-plasmodium-falciparum-and-bacterial-infection-in-anopheles-dirus
#8
Mohammad Behram Khan, Jonathan Wee Kent Liew, Cherng Shii Leong, Yee-Ling Lau
BACKGROUND: Anopheles mosquitoes transmit malaria which is one of the world's most threatening diseases. Anopheles dirus (sensu stricto) is among the main vectors of malaria in South East Asia. The mosquito innate immune response is the first line of defence against malaria parasites during its development. The immune deficiency (IMD) pathway, a conserved immune signaling pathway, influences anti-Plasmodium falciparum activity in Anopheles gambiae, An. stephensi and An. albimanus. The aim of the study was to determine the role of Rel2, an IMD pathway-controlled NF-kappaβ transcription factor, in An...
September 29, 2016: Parasites & Vectors
https://www.readbyqxmd.com/read/27560172/routine-in-vitro-culture-of-p-falciparum-gametocytes-to-evaluate-novel-transmission-blocking-interventions
#9
Michael J Delves, Ursula Straschil, Andrea Ruecker, Celia Miguel-Blanco, Sara Marques, Alexandre C Dufour, Jake Baum, Robert E Sinden
The prevention of parasite transmission from the human host to the mosquito has been recognized as a vital tool for malaria eradication campaigns. However, transmission-blocking antimalarial drug and/or vaccine discovery and development is currently hampered by the expense and difficulty of producing mature Plasmodium falciparum gametocytes in vitro-the parasite stage responsible for mosquito infection. Current protocols for P. falciparum gametocyte culture usually require complex parasite synchronization and addition of stimulating and/or inhibitory factors, and they may not have demonstrated the essential property of mosquito infectivity...
September 2016: Nature Protocols
https://www.readbyqxmd.com/read/27448565/a-novel-validated-assay-to-support-the-discovery-of-new-anti-malarial-gametocytocidal-agents
#10
Noemí Bahamontes-Rosa, María G Gomez-Lorenzo, Joël Lelièvre, Ane Rodriguez Alejandre, María Jesus Almela, Sonia Lozano, Esperanza Herreros, Francisco-Javier Gamo
BACKGROUND: Drugs that kill or inhibit Plasmodium gametocytes in the human host could potentially synergize the impact of other chemotherapeutic interventions by blocking transmission. To develop such agents, reliable methods are needed to study the in vitro activity of compounds against gametocytes. This study describes a novel assay for characterizing the activity of anti-malarial drugs against the later stages of Plasmodium falciparum gametocyte development using real-time PCR (qPCR)...
July 22, 2016: Malaria Journal
https://www.readbyqxmd.com/read/27350362/identification-and-classification-of-the-malaria-parasite-blood-developmental-stages-using-imaging-flow-cytometry
#11
Elya Dekel, Anna Rivkin, Meta Heidenreich, Yotam Nadav, Yifat Ofir-Birin, Ziv Porat, Neta Regev-Rudzki
Malaria is the most devastating parasitic disease of humans, caused by the unicellular protozoa of the Plasmodium genus, such as Plasmodium falciparum (Pf) and is responsible for up to a million deaths each year. Pf life cycle is complex, with transmission of the parasite between humans via mosquitos involving a remarkable series of morphological transformations. In the bloodstream, the parasites undergo asexual multiplications inside the red blood cell (RBC), where they mature through the ring (R), trophozoite (T) and schizont (S) stages, and sexual development, resulting in gametocytes (G)...
June 25, 2016: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/27297478/the-redox-cycler-plasmodione-is-a-fast-acting-antimalarial-lead-compound-with-pronounced-activity-against-sexual-and-early-asexual-blood-stage-parasites
#12
Katharina Ehrhardt, Christiane Deregnaucourt, Alice-Anne Goetz, Tzvetomira Tzanova, Valentina Gallo, Paolo Arese, Bruno Pradines, Sophie H Adjalley, Denyse Bagrel, Stephanie Blandin, Michael Lanzer, Elisabeth Davioud-Charvet
Previously, we presented the chemical design of a promising series of antimalarial agents, 3-[substituted-benzyl]-menadiones, with potent in vitro and in vivo activities. Ongoing studies on the mode of action of antimalarial 3-[substituted-benzyl]-menadiones revealed that these agents disturb the redox balance of the parasitized erythrocyte by acting as redox cyclers-a strategy that is broadly recognized for the development of new antimalarial agents. Here we report a detailed parasitological characterization of the in vitro activity profile of the lead compound 3-[4-(trifluoromethyl)benzyl]-menadione 1c (henceforth called plasmodione) against intraerythrocytic stages of the human malaria parasite Plasmodium falciparum We show that plasmodione acts rapidly against asexual blood stages, thereby disrupting the clinically relevant intraerythrocytic life cycle of the parasite, and furthermore has potent activity against early gametocytes...
September 2016: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/27123949/large-scale-production-of-plasmodium-falciparum-gametocytes-for-malaria-drug-discovery
#13
Sandra Duffy, Sasdekumar Loganathan, John P Holleran, Vicky M Avery
The tightly controlled induction of Plasmodium falciparum gametocytes in large-scale culture is a fundamental requirement for malaria drug discovery applications including, but not limited to, high-throughput screening. This protocol uses magnetic separation for isolation of hemozoin-containing parasites in order to (i) increase parasitemia, (ii) decrease hematocrit and (iii) introduce higher levels of young red blood cells in a culture simultaneously within 2-4 h. These parameters, along with red blood cell lysis products that are generated through schizont rupture, are highly relevant for enabling optimum induction of gametocytogenesis in vitro...
May 2016: Nature Protocols
https://www.readbyqxmd.com/read/27098483/genomic-variation-in-two-gametocyte-non-producing-plasmodium-falciparum-clonal-lines
#14
Susana Campino, Ernest Diez Benavente, Samuel Assefa, Eloise Thompson, Laura G Drought, Catherine J Taylor, Zaria Gorvett, Celine K Carret, Christian Flueck, Al C Ivens, Dominic P Kwiatkowski, Pietro Alano, David A Baker, Taane G Clark
BACKGROUND: Transmission of the malaria parasite Plasmodium falciparum from humans to the mosquito vector requires differentiation of a sub-population of asexual forms replicating within red blood cells into non-dividing male and female gametocytes. The nature of the molecular mechanism underlying this key differentiation event required for malaria transmission is not fully understood. METHODS: Whole genome sequencing was used to examine the genomic diversity of the gametocyte non-producing 3D7-derived lines F12 and A4...
April 21, 2016: Malaria Journal
https://www.readbyqxmd.com/read/26856913/limited-degradation-of-the-plasmodium-falciparum-gametocyte-marker-pfs25-mrna-exposed-to-tropical-temperatures-considerations-for-malaria-transmission-field-studies
#15
Andreea Waltmann, Stephan Karl, Chris Chiu, Ivo Mueller
An important aspect of many malaria molecular epidemiology and transmission studies is RNA-based detection of gametocytes. Ensuring RNA stability represents a challenge in tropical, resource-limited environments, as RNA may quickly degrade when samples are not preserved under adequate conditions. This study investigated the degradation of pfs25 messenger RNA (mRNA), the most widely used Plasmodium falciparum gametocyte marker, in whole blood spiked with cultured P. falciparum gametocytes, exposed to different temperatures for up to 48 hours, and collected with different anticoagulants...
April 2016: American Journal of Tropical Medicine and Hygiene
https://www.readbyqxmd.com/read/26573271/a-comparison-of-plasmodium-falciparum-circumsporozoite-protein-based-slot-blot-and-elisa-immuno-assays-for-oocyst-detection-in-mosquito-homogenates
#16
COMPARATIVE STUDY
Will Stone, Bryan Grabias, Kjerstin Lanke, Hong Zheng, Emily Locke, Diadier Diallo, Ashley Birkett, Merribeth Morin, Teun Bousema, Sanjai Kumar
BACKGROUND: The infectivity of Plasmodium gametocytes is typically determined by microscopically examining the midguts of mosquitoes that have taken a blood meal containing potentially infectious parasites. Such assessments are required for the development and evaluation of transmission-reducing interventions (TRI), but are limited by subjectivity, technical complexity and throughput. The detection of circumsporozoite protein (CSP) by enzyme-linked immunosorbent assay (ELISA) and enhanced chemiluminescent slot-blot (ECL-SB) may be used as objective, scalable alternatives to microscopy for the determination of infection prevalence...
November 14, 2015: Malaria Journal
https://www.readbyqxmd.com/read/26562778/activity-of-herbal-medicines-on-plasmodium-falciparum-gametocytes-implications-for-malaria-transmission-in-ghana
#17
Linda Eva Amoah, Courage Kakaney, Bethel Kwansa-Bentum, Kwadwo Asamoah Kusi
BACKGROUND: Malaria still remains a major health issue in Ghana despite the introduction of Artemisinin-based combination therapy (ACT) coupled with other preventative measures such as the use of insecticide treated nets (ITNs). The global quest for eradication of malaria has heightened the interest of identifying drugs that target the sexual stage of the parasite, referred to as transmission-blocking drugs. This study aimed at assessing the efficacy and gametocydal effects of some commonly used herbal malaria products in Ghana...
2015: PloS One
https://www.readbyqxmd.com/read/26416869/in-vitro-activities-of-primaquine-schizonticide-combinations-on-asexual-blood-stages-and-gametocytes-of-plasmodium-falciparum
#18
Mynthia Cabrera, Liwang Cui
Currently, the World Health Organization recommends addition of a 0.25-mg base/kg single dose of primaquine (PQ) to artemisinin combination therapies (ACTs) for Plasmodium falciparum malaria as a gametocytocidal agent for reducing transmission. Here, we investigated the potential interactions of PQ with the long-lasting components of the ACT drugs for eliminating the asexual blood stages and gametocytes of in vitro-cultured P. falciparum strains. Using the SYBR green I assay for asexual parasites and a flow cytometry-based assay for gametocytes, we determined the interactions of PQ with the schizonticides chloroquine, mefloquine, piperaquine, lumefantrine, and naphthoquine...
December 2015: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/26315106/specific-expression-and-export-of-the-plasmodium-falciparum-gametocyte-exported-protein-5-marks-the-gametocyte-ring-stage
#19
Marta Tibúrcio, Matthew W A Dixon, Oliver Looker, Sumera Younis Younis, Leann Tilley, Pietro Alano
BACKGROUND: Plasmodium falciparum sexual development plays a fundamental role in the transmission and spread of malaria. The ability to generate gametocytes can be lost during culture in vitro, often associated with the loss of a subtelomeric region of chromosome 9. Gametocytogenesis starts with erythrocyte invasion by a sexually committed merozoite, but the first available specific marker of sexual differentiation appears only from 24 h post invasion. METHODS: Specific antibodies and gene fusions were produced to study the timing of expression and the sub-cellular localization of the P...
2015: Malaria Journal
https://www.readbyqxmd.com/read/26239989/purification-methodology-for-viable-and-infective-plasmodium-vivax-gametocytes-that-is-compatible-with-transmission-blocking-assays
#20
Omaira Vera, Paula Brelas de Brito, Letusa Albrecht, Keillen Monick Martins-Campos, Paulo F P Pimenta, Wuelton M Monteiro, Marcus V G Lacerda, Stefanie C P Lopes, Fabio T M Costa
Significant progress toward the control of malaria has been achieved, especially regarding Plasmodium falciparum infections. However, the unique biology of Plasmodium vivax hampers current control strategies. The early appearance of P. vivax gametocytes in the peripheral blood and the impossibility of culturing this parasite are major drawbacks. Using blood samples from 40 P. vivax-infected patients, we describe here a methodology to purify viable gametocytes and further infect anophelines. This method opens new avenues to validate transmission-blocking strategies...
October 2015: Antimicrobial Agents and Chemotherapy
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