Publications by authors named "Clement Regnault"

One approach to interrupting the transmission of insect-borne diseases that is successfully used in veterinary medicine is exploiting the ability of antiparasitic drugs to make vertebrate blood toxic for blood-feeding insects. Recent studies have identified 4-hydroxyphenylpyruvate dioxygenase (HPPD), an enzyme of the tyrosine detoxification pathway, as essential for hematophagous arthropods to digest their blood meals. Such blood-feeding insects include anopheline mosquitoes, which transmit malaria-causing parasites.

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Alveolar echinococcosis (AE) is a severe zoonotic disease caused by the metacestode stage of the fox tapeworm Echinococcus multilocularis. We recently showed that E. multilocularis metacestode vesicles scavenge large amounts of L-threonine from the culture medium.

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African trypanosomiasis is a widespread disease of human and veterinary importance caused by various with a globally devastating impact and a need for novel treatment options. We here provide a comprehensive preclinical evaluation of nucleoside analogues, 6-thioether-modified tubercidins, with curative activity against African trypanosomiasis. Promising hits were identified following screening against the most relevant trypanosome species.

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Abnormal increases in cell size are associated with senescence and cell cycle exit. The mechanisms by which overgrowth primes cells to withdraw from the cell cycle remain unknown. We address this question using CDK4/6 inhibitors, which arrest cells in G0/G1 and are licensed to treat advanced HR+/HER2- breast cancer.

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In malaria drug discovery, understanding the mode of action of lead compounds is important as it helps in predicting the potential emergence of drug resistance in the field when these drugs are eventually deployed. In this study, we have employed metabolomics technologies to characterize the potential targets of anti-malarial drug candidates in the developmental pipeline at NITD. We show that NITD fast-acting leads belonging to spiroindolone and imidazothiadiazole class induce a common biochemical theme in drug-exposed malaria parasites which is similar to another fast-acting, clinically available drug, DHA.

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Acute febrile illnesses are still a major cause of mortality and morbidity globally, particularly in low to middle income countries. The aim of this study was to determine any possible metabolic commonalities of patients infected with disparate pathogens that cause fever. Three liquid chromatography-mass spectrometry (LC-MS) datasets investigating the metabolic effects of malaria, leishmaniasis and Zika virus infection were used.

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Article Synopsis
  • Scientists want to find out if there is life on other planets, and they look for special molecules called organic molecules that are found in all living things on Earth.
  • NASA's Perseverance rover and the future ExoMars rover are using special tools to detect these molecules on Mars, but they aren't as powerful as the machines we have here on Earth.
  • A meteorite that fell to Earth called Lafayette was studied, and scientists discovered it has many organic molecules, including a type of toxin, which could mean it came from a place with plants and even a possible student collector from Purdue University.
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Studies on microalgae interspecific interactions have so far focused either on nutrient competition or allelopathic effects due to excreted substances from Harmful Algal Bloom (HAB) species. Evidence from plants, bacteria and specific microalgae groups, point to a range of responses mediated by sensing or direct chemical impact of exometabolites from foreign species. Such processes remain under-investigated, especially in non-HAB microalgae, despite the importance of such knowledge in ecology and industrial applications.

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  • * The research aimed to analyze the serum metabolome of 12 dogs infected with babesiosis compared to 12 healthy dogs, using advanced chromatography techniques, leading to the identification of 295 metabolites.
  • * Findings revealed various metabolic pathways involved in the disease, highlighting the potential for using metabolomics to better understand host-pathogen interactions and the mechanisms behind babesiosis in dogs.
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Microorganisms can adopt a quiescent physiological condition which acts as a survival strategy under unfavorable conditions. Quiescent cells are characterized by slow or non-proliferation and a deep downregulation of processes related to biosynthesis. Although quiescence has been described mostly in bacteria, this survival skill is widespread, including in eukaryotic microorganisms.

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Falciparum malaria is clinically heterogeneous and the relative contribution of parasite and host in shaping disease severity remains unclear. We explored the interaction between inflammation and parasite variant surface antigen (VSA) expression, asking whether this relationship underpins the variation observed in controlled human malaria infection (CHMI). We uncovered marked heterogeneity in the host response to blood challenge; some volunteers remained quiescent, others triggered interferon-stimulated inflammation and some showed transcriptional evidence of myeloid cell suppression.

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Livestock diseases caused by Trypanosoma congolense, T. vivax and T. brucei, collectively known as nagana, are responsible for billions of dollars in lost food production annually.

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Article Synopsis
  • Mitochondrial metabolic remodeling is crucial in the life cycle of Trypanosoma brucei, with the insect stage using oxidative phosphorylation for ATP and the bloodstream stage shifting to aerobic glycolysis.
  • Researchers used in vitro methods to study changes in RNA, proteins, and metabolites during this metabolic shift, revealing a switch to an alternative oxidase pathway and increased proline consumption.
  • Reactive oxygen species (ROS) were found to play a key role in signaling for developmental progression, as inhibiting ROS production halted the differentiation process.
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  • * Researchers studied sand flies infected with a genetically modified parasite that expresses green fluorescent protein (GFP), allowing for the visualization of infection without harming the flies, using specialized microscopy techniques.
  • * The experiments revealed that while infected flies showed localized fluorescence indicating higher parasite populations in certain areas, non-infected flies had better survival rates, demonstrating a potential model for future research into sand fly infections and parasite transmission.
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Amphotericin B is an increasingly important tool in efforts to reduce the global disease burden posed by Leishmania parasites. With few other chemotherapeutic options available for the treatment of leishmaniasis, the potential for emergent resistance to this drug is a considerable threat. Here we characterised four novel amphotericin B-resistant Leishmania mexicana lines.

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In this review, we give an overview of the current state of microfluidic-based high-throughput drug assays. In this highly interdisciplinary research field, various approaches have been applied to high-throughput drug screening, including microtiter plate, droplets microfluidics as well as continuous flow, diffusion and concentration gradients-based microfluidic drug assays. Therefore, we reviewed over 100 recent publications in the field and sorted them according to their approach.

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Priming and activating immune stimuli have profound effects on macrophages, however, studies generally evaluate stimuli in isolation rather than in combination. In this study we have investigated the effects of pro-inflammatory and anti-inflammatory stimuli either alone or in combination on macrophage metabolism. These stimuli include host factors such as IFNγ and ovalbumin-immunoglobulin immune complexes, or pathogen factors such as LPS.

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African trypanosomes are responsible for significant levels of disease in both humans and animals. The protozoan parasites are free-living flagellates, usually transmitted by arthropod vectors, including the tsetse fly. In the mammalian host they live in the bloodstream and, in the case of human-infectious species, later invade the central nervous system.

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relies on monoallelic expression of 1 of 60 virulence genes for antigenic variation and host immune evasion. Each gene contains a conserved intron which has been implicated in previous studies in both activation and repression of transcription via several epigenetic mechanisms, including interaction with the promoter, production of long noncoding RNAs (lncRNAs), and localization to repressive perinuclear sites. However, functional studies have relied primarily on artificial expression constructs.

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