Publications by authors named "Edith Demettre"

Cattle trypanosomosis caused by is a widely distributed disease in Africa and Latin America. It causes significant losses in the livestock industry and is characterized by fluctuating parasitemia, anemia, fever, lethargy, and weight loss. In this study we evaluated the virulence (capacity to multiply inside the host and to modulate the host response) and pathogenicity (ability to produce disease and/or mortality) patterns of two strains (TvMT1 and TvLIEM176) in experimentally-infected sheep and determined the proteins differentially expressed in the proteomes of these two strains.

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Cattle trypanosomosis caused by Trypanosoma vivax is a widely distributed disease in Africa and Latin America. It causes significant losses in the livestock industry and is characterized by fluctuating parasitemia, anemia, fever, lethargy, and weight loss. In this study we evaluated the virulence (capacity to multiply inside the host and to modulate the host response) and pathogenicity (ability to produce disease and/or mortality) patterns of two T.

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The tropical bont tick, , is a tick species of veterinary importance and is considered as one of major pest of ruminants in Africa and in the Caribbean. It causes direct skin lesions, transmits heartwater, and reactivates bovine dermatophilosis. Tick saliva is reported to affect overall host responses through immunomodulatory and anti-inflammatory molecules, among other bioactive molecules.

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Background: The saliva of tsetse flies contains a cocktail of bioactive molecules inducing specific antibody responses in hosts exposed to bites. We have previously shown that an indirect-ELISA test using whole salivary extracts from Glossina morsitans submorsitans was able to discriminate between (i) cattle from tsetse infested and tsetse free areas and (ii) animals experimentally exposed to low or high numbers of tsetse flies. In the present study, our aim was to identify specific salivary synthetic peptides that could be used to develop simple immunoassays to measure cattle exposure to tsetse flies.

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Relics of ancient infections are abundant in eukaryote genomes, but little is known about how they evolve when they confer a functional benefit on their host. We show here, for the first time, that the virus-like particles shown to protect Venturia canescens eggs against host immunity are derived from a nudivirus genome incorporated by the parasitic wasp into its own genetic material. Nudivirus hijacking was also at the origin of protective particles from braconid wasps.

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A cross-talk in host-parasite associations begins when a host encounters a parasite. For many host-parasite relationships, this cross-talk has been taking place for hundreds of millions of years. The co-evolution of hosts and parasites, the familiar 'arms race' results in fascinating adaptations.

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Background: Malaria is the major parasitic disease worldwide caused by Plasmodium infection. The objective of integrated malaria control programs is to decrease malaria transmission, which needs specific tools to be accurately assessed. In areas where the transmission is low or has been substantially reduced, new complementary tools have to be developed to improve surveillance.

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Insensitive acetylcholinesterase resistance due to a mutation in the acetylcholinesterase (ace) encoding ace-1 gene confers cross-resistance to organophosphate and carbamate insecticides in Anopheles gambiae populations from Central and West Africa. This mutation is associated with a strong genetic cost revealed through alterations of some life history traits but little is known about the physiological and behavioural changes in insects bearing the ace-1(R) allele. Comparative analysis of the salivary gland contents between An.

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Intracellular pathogens including bacteria, viruses and protozoa hijack host cell functions to access nutrients and to bypass cellular defenses and immune responses. These strategies have been acquired through selective pressure and allowed pathogens to reach an appropriate cellular niche for their survival and growth. To get new insights on how parasites hijack host cellular functions, we developed a SILAC (Stable Isotope Labeling by Amino Acids in Cell culture) quantitative proteomics workflow.

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We have analyzed the comportment in in vitro culture of 2 different genotypes of Trypanosoma cruzi, the agent of Chagas disease, pertaining to 2 major genetic subdivisions (near-clades) of this parasite. One of the stocks was a fast-growing one, highly virulent in mice, while the other one was slow-growing, mildly virulent in mice. The working hypothesis was that mixtures of genotypes interact, a pattern that has been observed by us in empirical experimental studies.

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The saliva of blood sucking arthropods contains a number of pharmacologically active compounds that induce an antibody response in exposed human individuals. The objectives of the present study were (i) to assess the human IgG response directed against salivary antigens of Glossina palpalis gambiensis, the main vector of Trypanosoma brucei gambiense in West Africa, as a biomarker of human-tsetse contacts; and (ii) to identify specific salivary antigens. Immune reactivity of human plasma collected within active human African trypanosomiasis (HAT) foci (coastal Guinea), historical foci where tsetse flies are still present (South-West Burkina Faso) and a tsetse free area (Bobo-Dioulasso, Burkina Faso), was measured by ELISA against whole saliva extracts.

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Article Synopsis
  • The study focuses on the venom of the endoparasitoid wasp Hyposoter didymator and its role in host interaction, particularly with the moth Spodoptera frugiperda.
  • It was found that the wasp's venom did not significantly affect the host's immune response or growth, indicating that the venom may not be crucial for successful parasitism.
  • Proteomic analysis revealed a diverse range of proteins in the venom, but their functions appear to be overshadowed by the effects of symbiotic polydnaviruses present in the wasp's ovarian fluid.
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Hosts are frequently infected with more than one parasite or pathogen at any one time, but little is known as to how they respond to multiple immune challenges compared to those involving single infections. We investigated the proteome of Aedes aegypti larvae following infection with either Edhazardia aedis or Vavraia culicis, and coinfections involving both. They are both obligate intracellular parasites belonging to the phylum microsporidia and infect natural populations of Ae.

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Background: The Culex quinquefasciatus mosquito, a major pest and vector of filariasis and arboviruses in the tropics, has developed multiple resistance mechanisms to the main insecticide classes currently available in public health. Among them, the insensitive acetylcholinesterase (ace-1(R) allele) is widespread worldwide and confers cross-resistance to organophosphates and carbamates. Fortunately, in an insecticide-free environment, this mutation is associated with a severe genetic cost that can affect various life history traits.

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We performed a phylogenetic character mapping on 26 stocks of Trypanosoma cruzi, the parasite responsible for Chagas disease, and 2 stocks of the sister taxon T. cruzi marinkellei to test for possible associations between T. cruzi-subspecific phylogenetic diversity and levels of protein expression, as examined by proteomic analysis and mass spectrometry.

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Many thousands of endoparasitic wasp species are known to inject polydnavirus (PDV) particles into their caterpillar host during oviposition, causing immune and developmental dysfunctions that benefit the wasp larva. PDVs associated with braconid and ichneumonid wasps, bracoviruses and ichnoviruses respectively, both deliver multiple circular dsDNA molecules to the caterpillar. These molecules contain virulence genes but lack core genes typically involved in particle production.

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Mosquito-transmitted pathogens pass through the insect's midgut (MG) and salivary gland (SG). What occurs in these organs in response to a blood meal is poorly understood, but identifying the physiological differences between sugar-fed and blood-fed (BF) mosquitoes could shed light on factors important in pathogens transmission. We compared differential protein expression in the MGs and SGs of female Aedes aegypti mosquitoes after a sugar- or blood-based diet.

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Animal trypanosomosis is a major constraint to livestock productivity in the tropics and has a significant impact on the life of millions of people globally (mainly in Africa, South America and south-east Asia). In Africa, the disease in livestock is caused mainly by Trypanosoma congolense, Trypanosoma vivax, Trypanosoma evansi and Trypanosoma brucei brucei. The extracellular position of trypanosomes in the bloodstream of their host requires consideration of both the parasite and its naturally excreted-secreted factors (secretome) in the course of pathophysiological processes.

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Human cerebrospinal fluid (CSF) proteome is actively investigated to identify relevant biomarkers and therapeutic targets for neurological disorders. Approximately 80% of CSF proteome originate from plasma, yielding a high dynamic range in CSF protein concentration and precluding identification of potential biomarkers originating from CNS cells. Here, we have adapted the most complete multiaffinity depletion method available to remove 20 abundant plasma proteins from a CSF pool originating from patients with various cognitive disorders.

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The Plasmodium falciparum food vacuole (FV) is a lysosome-like organelle where erythrocyte hemoglobin digestion occurs. It is a favorite target in the development of antimalarials. We have used a tandem mass spectrometry approach to investigate the proteome of an FV-enriched fraction and identified 116 proteins.

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In Salmonella enterica serovar Typhimurium, MgtC and PagC are positively regulated by the PhoP-PhoQ two-component system, which is activated under magnesium deprivation. Both MgtC and PagC are of unknown function but have been involved in intramacrophage survival. We have found that the amount of PagC is lowered in a DeltamgtC mutant strain grown in magnesium depleted medium.

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Despite increasing evidence of behavioural manipulation of their vectors by pathogens, the underlying mechanisms causing infected vectors to act in ways that benefit pathogen transmission remain enigmatic in most cases. Here, 2-D DIGE coupled with MS were employed to analyse and compare the head proteome of mosquitoes (Anopheles gambiae sensu stricto (Giles)) infected with the malarial parasite (Plasmodium berghei) with that of uninfected mosquitoes. This approach detected altered levels of 12 protein spots in the head of mosquitoes infected with sporozoites.

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Choroid plexuses (CP) are involved in multiple functions related to their unique architecture and localization at the interface between the blood and cerebrospinal fluid compartments. These include the release by choroidal epithelial cells (CEC) of biologically active molecules, such as polypeptides, which are distributed globally to the brain. Here, we have used a proteomic approach to get an unbiased overview of the proteins that are secreted by primary cultures enriched in epithelial cells from mice CP.

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One of the major obstacles in proteomic analysis of biological fluids is the presence of highly abundant proteins such as albumin and immunoglobulins, which can interfere with the resolution and sensitivity of the proteome profiling techniques used. In this paper, we describe an anion exchange fractionation procedure for serum using denaturating conditions allowing protein-protein interaction disruption before analysis by surface-enhanced laser desorption/ionization and by two-dimensional electrophoresis. This method simplifies the serum proteome into subproteomes and markedly increases resolution and sensitivity without any loss of minor proteins.

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