Publications by authors named "Legendre R"

Microbial pathogenesis is mediated by the expression of virulence genes. However, as microbes with identical virulence gene content can differ in their pathogenic potential, other virulence determinants must be involved. Here, by combining comparative genomics and transcriptomics of a large collection of isolates of the model pathogen Listeria monocytogenes, time-lapse microscopy, in vitro evolution and in vivo experiments, we show that the individual stress responsiveness of L.

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Bacterial two-component systems (TCSs) are signaling modules that control physiology, adaptation, and host interactions. A typical TCS consists of a histidine kinase (HK) that activates a response regulator via phosphorylation in response to environmental signals. Here, we systematically test the effect of inactivating the conserved phosphatase activity of HKs to activate TCS signaling pathways.

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  • - Group B Streptococcus (GBS) can switch from being harmless to causing serious infections, particularly in newborns and the elderly, based on how it manages its virulence factors.
  • - The study focuses on the SaeRS two-component system, which helps regulate the expression of specific virulence factors that allow GBS to invade host cells and persist during infections.
  • - Findings show that while activating SaeRS can enhance GBS's ability to adhere to and invade host tissues, it may reduce overall virulence, highlighting the complex balance in bacterial pathogenesis.
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is among the few pathogens that have not developed resistance to ß-lactam antibiotics despite decades of clinical use. The molecular basis of this long-lasting susceptibility has not been investigated, and it is not known whether specific mechanisms constrain the emergence of resistance. In this study, we first report ß-lactam tolerance due to the inactivation of the c-di-AMP phosphodiesterase GdpP.

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In most vertebrates, adult neural stem cells (NSCs) continuously give rise to neurons in discrete brain regions. A critical process for maintaining NSC pools over long periods of time in the adult brain is NSC quiescence, a reversible and tightly regulated state of cell-cycle arrest. Recently, lysosomes were identified to regulate the NSC quiescence-proliferation balance.

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Rabies virus (RABV) is a lethal neurotropic virus that causes 60,000 human deaths every year globally. RABV infection is characterized by the suppression of the interferon (IFN)-mediated antiviral response. However, molecular mechanisms leading to RABV sensing by RIG-I-like receptors (RLR) that initiates IFN signaling currently remain elusive.

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Streptococcus gallolyticus sp. gallolyticus (SGG) is a gut pathobiont involved in the development of colorectal cancer (CRC). To decipher SGG contribution in tumor initiation and/or acceleration respectively, a global transcriptome was performed in human normal colonic cells (FHC) and in human tumoral colonic cells (HT29).

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The capacity to survive and thrive in conditions of limited resources and high inflammation is a major driver of tumor malignancy. Here we identified slow-cycling ADAM12PDGFRα mesenchymal stromal cells (MSCs) induced at the tumor margins in mouse models of melanoma, pancreatic cancer and prostate cancer. Using inducible lineage tracing and transcriptomics, we demonstrated that metabolically altered ADAM12 MSCs induced pathological angiogenesis and immunosuppression by promoting macrophage efferocytosis and polarization through overexpression of genes such as Gas6, Lgals3 and Csf1.

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  • Anti-CD20 monoclonal antibodies like Rituximab are used to treat lymphomas and autoimmune diseases by depleting B cells, but some patients resist this treatment for unclear reasons.
  • A CRISPR/Cas9 screen was conducted to find genes that affect the effectiveness of these antibodies, revealing MS4A1 (CD20) as expected and highlighting the role of Interferon Regulatory Factor 8 (IRF8) in the process.
  • IRF8 is crucial for maintaining CD20 levels, as its absence reduces the effectiveness of antibody-induced B cell depletion, providing new insights into why some patients resist anti-CD20 therapies.
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Pattern recognition receptors (PRRs) protect against microbial invasion by detecting specific molecular patterns found in pathogens and initiating an immune response. Although microbial-derived PRR ligands have been extensively characterized, the contribution and relevance of endogenous ligands to PRR activation remains overlooked. Here, we characterize the landscape of endogenous ligands that engage RIG-I-like receptors (RLRs) upon infection by different RNA viruses.

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  • The study investigates how the age of the mare impacts the gene expression in equine blastocysts, revealing differences between younger (6-year-old) and older (over 10-year-old) mares.
  • Results showed that while maternal age did not affect embryo recovery rates or size, it did disturb gene expression related to mitochondria and protein metabolism, particularly in the inner cell mass.
  • The findings suggest that maternal aging can significantly impact embryo development and potentially contribute to reduced fertility in older mares, marking an important insight for the equine industry.
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We present ePeak, a Snakemake-based pipeline for the identification and quantification of reproducible peaks from raw ChIP-seq, CUT&RUN and CUT&Tag epigenomic profiling techniques. It also includes a statistical module to perform tailored differential marking and binding analysis with state of the art methods. ePeak streamlines critical steps like the quality assessment of the immunoprecipitation, spike-in calibration and the selection of reproducible peaks between replicates for both narrow and broad peaks.

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  • After babies are born, their intestines change a lot from being weak to strong and working properly.
  • Scientists studied mice to find out about special cells that help the intestines grow and mature.
  • They discovered that blocking these important cells made it harder for the intestines to grow and heal, showing how crucial they are right after birth.
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  • The study investigates the relationship between bacteria, their viruses (bacteriophages), and human health, particularly how these populations coexist in the digestive tract.
  • Researchers used RNA sequencing to identify genes in E. coli that changed expression in different environments, finding specific genes that affected how E. coli interacted with virulent phages.
  • This research highlights the complex dynamics among bacteria, phages, and host organisms, showing that gene regulation impacts their interactions and overall balance in the intestines.
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The protozoan parasite Leishmania donovani causes fatal human visceral leishmaniasis in absence of treatment. Genome instability has been recognized as a driver in Leishmania fitness gain in response to environmental change or chemotherapy. How genome instability generates beneficial phenotypes despite potential deleterious gene dosage effects is unknown.

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  • * In a study with mice, it was found that these "trained" ILC3s not only survive for months after being activated but also have improved ability to multiply and produce interleukin-22 (IL-22) when faced with a second infection.
  • * These findings suggest that temporary exposure to pathogens can lead to lasting enhancements in ILC3 functions, strengthening the immune response in the intestines over time.
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Rabies is a zoonotic disease caused by rabies virus (RABV). As rabies advances, patients develop a variety of severe neurological symptoms that inevitably lead to coma and death. Unlike other neurotropic viruses that can induce symptoms of a similar range, RABV-infected brains do not show significant signs of inflammation nor the structural damages on neurons.

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Coronavirus RNA-dependent RNA polymerases produce subgenomic RNAs (sgRNAs) that encode viral structural and accessory proteins. User-friendly bioinformatic tools to detect and quantify sgRNA production are urgently needed to study the growing number of next-generation sequencing (NGS) data of SARS-CoV-2. We introduced sgDI-tector to identify and quantify sgRNA in SARS-CoV-2 NGS data.

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In animals with distinct life stages such as holometabolous insects, adult phenotypic variation is often shaped by the environment of immature stages, including their interactions with microbes colonizing larval habitats. Such carry-over effects were previously observed for several adult traits of the mosquito Aedes aegypti after larval exposure to different bacteria, but the mechanistic underpinnings are unknown. Here, we investigated the molecular changes triggered by gnotobiotic larval exposure to different bacteria in Ae.

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  • - Pathogenic Leptospira bacteria cause leptospirosis, a severe and widespread zoonotic disease, particularly affecting impoverished populations in sub-tropical regions.
  • - Researchers identified a new PerR-like regulator called PerRB in L. interrogans, which, alongside another regulator PerRA, helps the bacteria adapt to oxidative stress during infection.
  • - The study found that while single mutations in perRA or perRB increased tolerance to specific oxidants, a double mutation rendered the bacteria avirulent, highlighting the complex regulation of virulence through oxidative stress adaptation in pathogenic Leptospira.
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Benzodiazepines are one of the most commonly used medications in the field of anesthesia. They offer excellent anxiolytic and amnestic properties ideal for the perioperative period when patient anxiety is understandably heightened. Remimazolam has presented a favorable alternative to some of the common intravenous anesthetic agents used given its fast onset of action, high safety profile, and reasonably short duration of action.

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  • Spirochetes, like the bacteria Leptospira, have a unique spiral shape and specific flagella that are essential for movement, and this study examines the roles of two proteins, FlhF and FlhG, in controlling these flagella.*
  • The research found that while FlhF is crucial for Leptospira's motility, mutations in FlhG resulted in decreased movement in both saprophytic and pathogenic strains, without causing hyperflagellation as seen in other bacteria.*
  • Additionally, it was revealed through various tests that FlhG negatively regulates certain flagellar genes and that its function is not interchangeable across species, impacting the virulence of L. interrogans in a hamster model.*
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Virulence of the neonatal pathogen Group B Streptococcus is under the control of the master regulator CovR. Inactivation of CovR is associated with large-scale transcriptome remodeling and impairs almost every step of the interaction between the pathogen and the host. However, transcriptome analyses suggested a plasticity of the CovR signaling pathway in clinical isolates leading to phenotypic heterogeneity in the bacterial population.

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HP1 proteins are best known as markers of heterochromatin and gene silencing. Yet, they are also RNA-binding proteins and the HP1γ/CBX3 family member is present on transcribed genes together with RNA polymerase II, where it regulates co-transcriptional processes such as alternative splicing. To gain insight in the role of the RNA-binding activity of HP1γ in transcriptionally active chromatin, we have captured and analysed RNAs associated with this protein.

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CD4 T cell responses constitute an important component of adaptive immunity and are critical regulators of anti-microbial protection. CD4 T cells expressing CD32a have been identified as a target for HIV. CD32a is an Fcγ receptor known to be expressed on myeloid cells, granulocytes, B cells and NK cells.

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