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Ouologuem D.T.,University of Pennsylvania | Ouologuem D.T.,Malaria Research and Training Center | Roos D.S.,University of Pennsylvania
Journal of Cell Science | Year: 2014

Unlike most cells, protozoa in the phylum Apicomplexa divide by a distinctive process in which multiple daughters are assembled within the mother (schizogony or endodyogeny), using scaffolding known as the inner membrane complex (IMC). The IMC underlies the plasma membrane during interphase, but new daughters develop in the cytoplasm, as cytoskeletal filaments associate with flattened membrane cisternae (alveolae), which elongate rapidly to encapsulate subcellular organelles. Newly assembled daughters acquire their plasma membrane as they emerge from the mother, leaving behind vestiges of the maternal cell. Although the maternal plasma membrane remains intact throughout this process, the maternal IMC disappears -is it degraded, or recycled to form the daughter IMC? Exploiting fluorescently tagged IMC markers, we have used live-cell imaging, fluorescence recovery after photobleaching (FRAP) and mEos2 photoactivation to monitor the dynamics of IMC biogenesis and turnover during the replication of Toxoplasma gondii tachyzoites. These studies reveal that the formation of the T. gondii IMC involves two distinct steps - de novo assembly during daughter IMC elongation within the mother cell, followed by recycling of maternal IMC membranes after the emergence of daughters from the mother cell. © 2014. Published by The Company of Biologists Ltd. Source


Gregory R.,University of Liverpool | Darby A.C.,University of Liverpool | Coulibaly M.B.,Malaria Research and Training Center | Hughes M.,University of Liverpool | And 3 more authors.
PLoS ONE | Year: 2011

Background: Anopheles funestus is one of the major malaria vectors in Africa and yet there are few genomic tools available for this species compared to An. gambiae. To start to close this knowledge gap, we sequenced the An. funestus transcriptome using cDNA libraries developed from a pyrethroid resistant laboratory strain and a pyrethroid susceptible field strain from Mali. Results: Using a pool of life stages (pupae, larvae, adults: females and males) for each strain, 454 sequencing generated 375,619 reads (average length of 182 bp). De novo assembly generated 18,103 contigs with average length of 253 bp. The average depth of coverage of these contigs was 8.3. In total 20.8% of all reads were novel when compared to reference databases. The sequencing of the field strain generated 204,758 reads compared to 170,861 from the insecticide resistant laboratory strain. The contigs most differentially represented in the resistant strain belong to the P450 gene family and cuticular genes which correlates with previous studies implicating both of these gene families in pyrethroid resistance. qPCR carried out on six contigs indicates that these ESTs could be suitable for gene expression studies such as microarray. 31,000 sites were estimated to contain Single Nucleotide Polymorphisms (SNPs) and analysis of SNPs from 20 contigs suggested that most of these SNPs are likely to be true SNPs. Gene conservation analysis confirmed the close phylogenetic relationship between An. funestus and An. gambiae. Conclusion: This study represents a significant advance for the genetics and genomics of An. funestus since it provides an extensive set of both Expressed Sequence Tags (ESTs) and SNPs which can be readily adopted for the design of new genomic tools such as microarray or SNP platforms. © 2011 Gregory et al. Source


Vernet G.,Fondation Merieux | Altmann D.M.,Imperial College London | Doumbo O.,Malaria Research and Training Center | Bhutta Z.A.,Aga Khan University | And 2 more authors.
Emerging Infectious Diseases | Year: 2014

Antimicrobial drug resistance is usually not monitored in under-resourced countries because they lack surveillance networks, laboratory capacity, and appropriate diagnostics. This accelerating problem accounts for substantial number of excess deaths, especially among infants. Infections particularly affected by antimicrobial drug resistance include tuberculosis, malaria, severe acute respiratory infections, and sepsis caused by gram-negative bacteria. Nonetheless, mapping antimicrobial drug resistance is feasible in under-resourced countries, and lessons can be learned from previous successful efforts. Specimen shipping conditions, data standardization, absence of contamination, and adequate diagnostics must be ensured. As a first step toward solving this problem, we propose that a road map be created at the international level to strengthen antimicrobial resistance surveillance in under-resourced countries. This effort should include a research agenda; a map of existing networks and recommendations to unite them; and a communication plan for national, regional, and international organizations and funding agencies. Source


Tshefu A.K.,University of Kinshasa | Gaye O.,Cheikh Anta Diop University | Kayentao K.,Malaria Research and Training Center | Thompson R.,National Health Research Institute | And 9 more authors.
The Lancet | Year: 2010

Background There is a need for new artemisinin-based combination therapies that are convenient, eff ective, and safe. We compared the efficacy and safety of pyronaridine-artesunate with that of artemether-lumefantrine for treatment of uncomplicated P falciparum malaria. Methods This phase 3, parallel-group, double-blind, randomised, non-inferiority trial was undertaken in seven sites in Africa and three sites in southeast Asia. In a double-dummy design, patients aged 3-60 years with uncomplicated P falciparum malaria were randomly assigned in a 2:1 ratio to receive pyronaridine-artesunate once a day or artemetherlumefantrine twice a day, orally for 3 days, plus respective placebo. Randomisation was done by computer-generated randomisation sequence in blocks of nine by study centre. Intervention tablets contained 180 mg pyronaridine and 60 mg artesunate; control tablets contained 20 mg artemether and 120 mg lumefantrine. Both treatments were given according to bodyweight. The primary effi cacy outcome was PCR-corrected adequate clinical and parasitological response (ACPR) rate at day 28 in the per-protocol population. Non-inferiority was shown if the lower limit of the twosided 95% CI for the diff erence between groups was greater than-5%. This study is registered with ClinicalTrials.gov, number NCT00422084. Findings 1272 patients were randomly assigned to treatment (pyronaridine-artesunate, n=849; artemether-lumefantrine, n=423). The per-protocol population consisted of 784 patients in the pyronaridine-artesunate group and 386 patients in the artemether-lumefantrine group. PCR-corrected ACPR rate at day 28 was 99·5% (780 patients; 95% CI 98·7-99·9) in the pyronaridine-artesunate group and 99·2% (383 patients; 95% CI 97·7-99·8) in the artemether-lumefantrine group (treatment diff erence 0·3%, 95% CI-0·7 to 1·8; p=0·578). There were 509 (60·0%) adverse events in 849 patients assigned to pyronaridine-artesunate and 241 (57·0%) in 423 patients assigned to artemether-lumefantrine. The most frequent drug-related adverse event was eosinophilia (pyronaridine-artesunate, 53 events [6·2%]; artemether-lumefantrine 24 events [5·7%]). 21 (2·5%) patients in the pyronaridine-artesunate group and seven (1·7%) in the artemetherlumefantrine group discontinued study drugs or were withdrawn from the study. Mild and transient increases in alanine aminotransferase and aspartate aminotransferase concentrations were seen in the pyronaridine-artesunate group but not in the artemether-lumefantrine group. Interpretation Effi cacy of pyronaridine-artesunate was non-inferior to that of artemether-lumefantrine for treatment of uncomplicated falciparum malaria. Pyronaridine-artesunate should be considered for inclusion in malaria treatment programmes. Funding Shin Poong Pharmaceutical and the Medicines for Malaria Venture. Source


Ghansah A.,Noguchi Institute | Amenga-Etego L.,Navrongo Health Research Center | Amambua-Ngwa A.,Medical Research Council | Andagalu B.,U.S. Army | And 19 more authors.
Science | Year: 2014

The African continent continues to bear the greatest burden of malaria and the greatest diversity of parasites, mosquito vectors, and human victims. The evolutionary plasticity of malaria parasites and their vectors is a major obstacle to eliminating the disease. Of current concern is the recently reported emergence of resistance to the front-line drug, artemisinin, in South-East Asia in Plasmodium falciparum, which calls for preemptive surveillance of the African parasite population for genetic markers of emerging drug resistance. Here we describe the Plasmodium Diversity Network Africa (PDNA), which has been established across 11 countries in sub-Saharan Africa to ensure that African scientists are enabled to work together and to play a key role in the global effort for tracking and responding to this public health threat. Source

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