Publications by authors named "Gaume B"

Article Synopsis
  • The study investigates the role of meningitis in child mortality under five years old, particularly focusing on data from six sub-Saharan African countries and Bangladesh.
  • It employs post-mortem minimally invasive tissue sampling (MITS) to identify the causes of death and pathogens responsible for meningitis in this age group from December 2016 to December 2023.
  • Findings reveal that meningitis contributed to 7% of child deaths, with common pathogens identified being Acinetobacter baumannii and Klebsiella pneumoniae, particularly affecting neonates and infants.
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Measles deaths highlight immunization program gaps. In the Child Health and Mortality Prevention Surveillance study in Mali, we observed a rise in under-5 measles-related deaths in 2022 that corresponded with increased measles cases at the same time and a decline in measles vaccine coverage in Mali in 2020.

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This article presents the development of a digital twin model of a thigh portion subjected to various thermal treatments. Two scenarios are investigated: cold water immersion (CWI) and whole body cryotherapy (WBC), for which the comparison of numerical results with experimental measurements validates the consistency of the developed model. The use of real geometry on a first subject demonstrates the high heterogeneity of the temperature field and the need for accurate geometry.

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Given a Graph G = (V, E) and two vertices i, j ∈ V, we introduce Confluence(G, i, j), a vertex mesoscopic closeness measure based on short Random walks, which brings together vertices from a same overconnected region of the Graph G, and separates vertices coming from two distinct overconnected regions. Confluence becomes a useful tool for defining a new Clustering quality function QConf(G, Γ) for a given Clustering Γ and for defining a new heuristic Starling to find a partitional Clustering of a Graph G intended to optimize the Clustering quality function QConf. We compare the accuracies of Starling, to the accuracies of three state of the art Graphs Clustering methods: Spectral-Clustering, Louvain, and Infomap.

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Chlordecone is a persistent organochlorine pesticide widely used between 1972 and 1993 in the French West Indies to control the root borer in banana fields. Chlordecone use resulted in long-term pollution of soils, contamination of waters, of aquatic organisms, and of fields. Chlordecone is known to be neurotoxic, to increase prostate cancer, and to have negative effects on cognitive and motor development during infancy.

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The molluscan shell is a remarkable product of a highly coordinated biomineralisation process, and is composed of calcium carbonate most commonly in the form of calcite or aragonite. The exceptional mechanical properties of this biomaterial are imparted by the embedded organic matrix which is secreted by the underlying mantle tissue. While many shell-matrix proteins have already been identified within adult molluscan shell, their presence and role in the early developmental stages of larval shell formation are not well understood.

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Mollusc shell biomineralisation involves a variety of organic macromolecules (matrix proteins and enzymes) that control calcium carbonate (CaCO3) deposition, growth of crystals, the selection of polymorph, and the microstructure of the shell. Since the mantle and the hemocytes play an important role in the control of shell formation, primary cell cultures have been developed to study the expression of three biomineralisation genes recently identified in the abalone Haliotis tuberculata: a matrix protein, Lustrin A, and two carbonic anhydrase enzymes. Mantle cells and hemocytes were successfully maintained in primary cultures and were evaluated for their viability and proliferation over time using a semi-automated assay (XTT).

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Carbonic anhydrases (CAs) represent a diversified family of metalloenzymes that reversibly catalyze the hydration of carbon dioxide. They are involved in a wide range of functions, among which is the formation of CaCO(3) skeletons in metazoans. In the shell-forming mantle tissues of mollusks, the location of the CA catalytic activity is elusive and gives birth to contradicting views.

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Triclosan (2,4,4'-trichloro-2'-hydroxy-diphenyl ether; TCS) is an antibacterial agent incorporated in a wide variety of household and personal care products. Because of its partial elimination in sewage treatment plants, TCS is commonly detected in natural waters and sediments. Moreover, due to its high hydrophobicity, TCS accumulates in fatty tissues in various aquatic organisms.

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Analysis of the 18S rDNA sequences of Haliotis tuberculata tuberculata and H. t. coccinea subtaxa identified two different types of 18S rDNA genes and ITS1 regions.

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Rationale: β₂-agonists, the most common treatment for asthma, have a wide interindividual variability in response, which is partially attributed to genetic factors. We previously identified single nucleotide polymorphisms in the arginase 1 (ARG1) gene, which are associated with β₂-agonist bronchodilator response (BDR).

Objectives: To identify cis-acting haplotypes in the ARG1 locus that are associated with BDR in patients with asthma and regulate gene expression in vitro.

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An integrated study of shell formation was initiated covering the entire life cycle of the marine gastropod Haliotis tuberculata. Shell microstructure, chemistry and mineralogy were investigated by polarized microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX) and infra-red (IR) spectroscopy. SEM images of trochophore and veliger larvae showed the different stages of shell growth from the initial shell field to the late calcified protoconch.

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Cardiomyopathic effects of beta-adrenergic receptor (betaAR) signaling are primarily due to the beta(1)AR subtype. beta(1)/beta(2)AR and beta(1)/adenylyl cyclase type 5 (AC5) bitransgenic mice were created to test the hypothesis that beta(2)AR or AC5 co-overexpression has beneficial effects in beta(1)AR-mediated cardiomyopathy. In young mice, beta(1)/beta(2) hearts had a greater increase in basal and isoproterenol-stimulated contractility compared to beta(1)/AC5 and beta(1)AR hearts.

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The beta(1)-adrenergic receptor (beta(1)AR; ADRB1) polymorphism Arg389Gly is located in an intracellular loop and is associated with distinct human and mouse cardiovascular phenotypes. To test the hypothesis that beta(1)-Arg389 and beta(1)-Gly389 alleles could differentially couple to pathways beyond that of classic G(s)-adenylyl cyclase (AC)/cAMP signaling, we performed comparative gene expression profile analyses on hearts from wild-type and transgenic mice that expressed either human beta(1)-Arg389 or beta(1)-Gly389 receptors, or AC5, sampling at an early age prior to the onset of pathological features. All three models upregulated the expression of genes associated with RNA metabolism and translation and downregulated genes associated with mitochondria and energy metabolism, consistent with shared cAMP-driven increase in cardiac contractility, protein synthesis, and compensatory downregulation of mitochondrial energy production.

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This paper aims to validate reference genes for gene expression studies between light and dark conditions in the scleractinian coral Stylophora pistillata for future gene expression studies of the "light-enhanced calcification" phenomenon. For this purpose, we cloned, sequenced, and characterized a candidate reference gene, the 36B4 gene from the coral S. pistillata, and validated 36B4 and beta-actin as reference genes.

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Bcl-x(L) is a potent inhibitor of apoptosis. While Bcl-x(L) can be bound to mitochondria, a substantial fraction, depending on the cell type or tissue, is found in the cytosol of healthy cells. Gel filtration and crosslinking experiments reveal that, unlike monomeric Bax, Bcl-x(L) migrates in a complex of approximately 50 kDa in the cytosol.

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Mitochondrial outer-membrane permeabilization by pro-apoptotic Bcl-2 family members plays a crucial role in apoptosis induction. However, whether this directly causes the release of the different mitochondrial apoptogenic factors simultaneously is currently unknown. Here we report that in cells or with isolated mitochondria, pro-apoptotic Bcl-2 proteins cause the release of cytochrome c, Smac/Diablo and HtrA2/Omi but not endonuclease G (EndoG) and apoptosis-inducing factor (AIF).

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Mitochondrial fusion may regulate mitochondrial morphogenesis and underlie complementation between mitochondrial genomes in mammalian cells. The nuclear encoded mitochondrial proteins Mfn1 and Mfn2 are human homologues of the only known protein mediators of mitochondrial fusion, the Drosophila Fzo GTPase and Saccharomyces cerevisiae yFzo1p. Although the Mfn1 and Mfn2 genes were broadly expressed, the two genes showed different levels of mRNA expression in different tissues.

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We find that Bax, a proapoptotic member of the Bcl-2 family, translocates to discrete foci on mitochondria during the initial stages of apoptosis, which subsequently become mitochondrial scission sites. A dominant negative mutant of Drp1, Drp1K38A, inhibits apoptotic scission of mitochondria, but does not inhibit Bax translocation or coalescence into foci. However, Drp1K38A causes the accumulation of mitochondrial fission intermediates that are associated with clusters of Bax.

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In healthy cells, fusion and fission events participate in regulating mitochondrial morphology. Disintegration of the mitochondrial reticulum into multiple punctiform organelles during apoptosis led us to examine the role of Drp1, a dynamin-related protein that mediates outer mitochondrial membrane fission. Upon induction of apoptosis, Drp1 translocates from the cytosol to mitochondria, where it preferentially localizes to potential sites of organelle division.

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Nuclear-encoded mitochondrial matrix proteins in most cases contain N-terminal targeting signals and are imported in a linear N- to C-terminal (N-->C) fashion. We asked whether import can also occur in a C- to N-terminal direction (C-->N). We placed targeting signals at the C-terminus of passenger proteins.

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Unfolding of preproteins and translocation across the mitochondrial membranes requires their interaction with mt-Hsp70 and Tim44 at the inner face of the inner membrane and ATP as an energy source. We measured the temperature dependence of the rates of unfolding and import into the matrix of two folded passenger domains, the tightly folded heme-binding domain (HBD) of cytochrome b2 and the loosely folded mouse dihydrofolate reductase (DHFR). Despite the stability of the HBD, its rates of thermal breathing were fast and the preprotein was imported rapidly at all temperatures.

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Mdj1p, a DnaJ homolog in the mitochondria of Saccharomyces cerevisiae, is involved in the folding of proteins in the mitochondrial matrix. In this capacity, Mdj1p cooperates with mitochondrial Hsp70 (mt-Hsp70). Here, we analyzed the role of Mdj1p as a chaperone for newly synthesized proteins encoded by mitochondrial DNA and for nucleus-encoded proteins as they enter the mitochondrial matrix.

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Flavocytochrome b2 catalyzes the two-electron oxidation of L-lactate. Reducing equivalents are transferred first to FMN then to heme b2 in the same subunit, finally to cytochrome c or a non-physiological acceptor. The enzyme's three-dimensional structure, when analyzed in the light of existing mechanistic knowledge, suggested that His 373 is the active site base which initiates the substrate chemical transformation by abstracting the lactate alpha-proton.

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