In the context of the swiss consortion InfectX (www.infectx.ch), we performed siRNA and drug screens to investigate the invasion of host cells by the bacterial pathogen Listeria monocytogenes. As a primary readout for infection we detected by fluorescence microscopy the presence of the bacterially-secreted protein InlC, which accumulates in the cytoplasm of infected cells (Kühbacher et al. 2013). A first manuscript concerning the analysis of a kinome-wide siRNA library and a drug library has been published recently (Rämö et al. 2014) and the analysis of a genome-wide siRNA screen has been submitted for publication (Kühbacher et al. In Revision), in which major signaling pathways subverted by L. monocytogenes are identified. However, besides the presence of InlC, many other features have been measured in infected cells including InlC intensity, bacterial distribution in host cells, actin morphology and distribution, cellular replication state, cellular context of infected cells, etc. We intend to analyze the full set of measured parameters in order to identify global signaling cascades subverted by L. monocytogenes for infection or used by the cell to control bacterial proliferation.

Several mycobacterial species have been used for the screening of chemical libraries with the aim of avoiding natural resistance mechanisms developed by specific species. In this way, different compounds with antibacterial activity have been identified. Mutants resistant to each compound have been isolated and their genomes have been sequenced. The comparison of these sequences with the wild type strain genome will allow us to identify the targets for the antibacterial activity and the mechanism of action of the molecules. This will be instrumental for improving molecules for a better antibacterial activity with emphasis on tuberculosis.

Modification of MacSyFinder models and profiles data structure to facilitate models distribution, and integration in the Mobyle platform. This consists in organizing the way XML models and HMM profiles of given system or set of systems in order to allow running the detection of all the macromolecular systems in a given folder. This will also ensure that the profiles are always distributed with the appropriate definitions of the systems, and thus avoid collisions of profiles name.

CRISPR-Cas9 tools have recently emerged as a very powerful way to edit genomes and control gene expression. The Cas9 protein is an endonuclease that can be guided by a small guide RNA (gRNA) to any target DNA sequence of choice. This feature has enabled the construction of gRNA libraries to perform genome-wide CRISPR-Cas9 functional screens. Such screens have notably been used to identify factors involved in drug and toxin resistance in human cells. We are now in the process of developing such a screen for bacteria. In this screen, we use the catalytic null mutant of Cas9 known as dCas9 to block transcription at target positions and knockdown genes. The purpose of this project is to investigate the properties of this type of screen in bacteria.

Listeria monocytogenes is a gram positive facultative intracellular foodborne bacterium responsible for serious clinical manifestations including febrile gastroenteritis, meningitis, encephalitis and maternofetal infections in humans and livestock. Intestinal microbiota plays fundamental roles in the resistance to foodborne infections. Intestinal microbiota commensals protect against pathogens by direct antimicrobial activity through production of bacteriocins, competition for nutrients or binding sites, stimulation of epithelial barrier function, immunomodulation and inhibition of virulence factors expression in gastrointestinal pathogens. On the other side, pathogens have developed tools to avoid commensal-mediated resistance to colonization. Thus, the interplay between gut commensals and L. monocytogenes is critical for the infection and the development of the disease. We have identified a Listeria monocytogenes toxin which modifies the intestinal host microbiota and allows Listeria survival in the intestinal content to later invade the intestine and deeper organs.

The PIBnet initiative is a joint effort by the above laboratories to modernize their activities, including collection management and microbial characterization approaches and technologies. Within this large concerted effort, a priority is to promote WGS as the major characterization approach of microbial agents for surveillance and outbreak investigation. Our ambition is to have shifted to WGS as a routine strain characterization method for epidemiological surveillance and outbreak investigation in the Institut Pasteur NRCs at the end of 2016. The target volume is 10 000 genomes a year. On the bioinformatics level, this requires implementing (1) fast data treatment tools and (2) Genotyping/classification schemes and methods to extract medically relevant information from genomic sequences (resistome, virulome).

Transfert des annotations d'un fichier genbank sur une séquence fasta ayant une région de 183 kb inversée par rapport à la séquence parentale

We are examining differences within the genomes of E. coli strains.

Improvement of two existing tools, COV2HTML (published in 2014) and SEQ2HTML (private), and transform two scripts into interactive web interfaces addressed to biologists.  

Legionella pneumophila is from a genomic point of view a very diverse species, however, only few clones are responsible for over 50% of all human disease cases. Thus we aim to understand the evolution and emergence of these 5 major disease related clones. We have sequenced a large number L. pneumophila strains belonging to these clones and are undertaking comparative and phylogenetic genome analyses.

We wish to investigate the extent of conservation and prevalence of small orfs of unknown function expressed in stationary phase of growth in Salmonella

To perform assignment of 16S sequences to bacterial genera and statistical analysis of variations of bacterial populations collected from mice feces

The colonisation of the murine gut by commensal bacteria has been shown to profoundly influence the host physiology. We would like to investigate if these effects are in part mediated by changes in epitranscriptomics, i.e. mRNA modifications influencing the stability and degradation of mRNA (Dominissini et al. Cell 2012, Meyer et al. Nature 2012). To this end, we aim to investigate the levels of the m6A modification of mRNA and differentially methylated targets in organs derived from mice with a conventional flora, germ-free mice and gnotobiotic mice colonized with a specific commensal, Akkermansia muciniphila, known for benificial effects on host metabolism (Everard et al. PNAS 2012, Shin et al. Gut 2014). Since also pathogenic bacteria have been shown to influence the host cells on many levels, including the dysregulation of transcription in the host, we would like to extend our study of host mRNA methylation patterns to mice that have been intra-gastrically infected with Listeria monocytogenes in the presence or absence of commensal bacteria.

The tool MacSyFinder and the viewer MacSyView provide a framework to model macromolecular systems in genomes, allow their precise detection, and their visualisation in genomic context. These tools were co-developped by Sophie Abby, Bertrand Néron, Hervé Ménager, Marie Touchon and Eduardo Rocha. MacSyFinder has been the subject of a demand for a US patent by the Institut Pasteur. The aim of the project is to increase the value and accessibility of these tools by designing a web interface, and giving the possibility to run MacSyFinder on a remote server in Pasteur, with a set of predefined model systems, or with user-supplied models. This will make these tools more easily accessible by a broad audience of biologists.

Leptospiral promoter regions are poorly characterized: experimentally proven transcription factor binding sites have not been described in the literature and promoter prediction algorithms and E. coli consensus sequences of DNA motifs are not appropriate for Leptospira. Identification of Transcription Start Sites (TSS) and promoters on a global scale will provide essential information on DNA motifs that are targets of RNA polymerases, sigma factors and transcription factors. RNA sequencing will also provide information on small regulatory RNAs. These small (~30-500 nt) non-coding RNAs (sRNAs) are an emerging class of post-transcriptional regulators which play a variety of important roles in many biological processes. Studies on sRNA regulation of gene expression in Leptospira are currently in their infancy. Our results will provide new insights into the transcriptional landscape of L. interrogans, including the repertoire of sRNA, and it will establish the foundation for future experimental work on gene regulation.    

Integrons drive the spread of antibiotic resistance genes in bacterial populations. While their role is widely known (integron+antibiotic+resistance in PubMed gives > 1700 hits), there was no software available to identify integrons and their different components. We have made a script (in Python) which annotates DNA sequences (with prodigal), then identifies the integrase of the integron (using hmm protein profiles), searches attC sites (using covariance models from structurally annotated multiple sequence alignments of DNA sequences), searches certain types of promoters (string search using Python functions), and outputs all this and the genes in the cassettes (between attC sites). We would like the program to be available via Mobyle (or other convenient way) as a web server. Thus would facilitate its use by most biologists (which could still use the scripts if they wish to). It would also facilitate the publication of the methodological manuscript.

Assemblage de novo d'une souche bactérienne afin de pourvoir la soumettre dans une plateforme d'annotation.

Les cyanobactéries sont des microorganismes qui prolifèrent dans de nombreux plans d’eau et perturbent leurs fonctionnements et leurs usages car elles sont capables de produire des toxines dangereuses pour la santé humaine et animale. Si la réglementation sanitaire est basée, pour l’instant, sur la surveillance d’une seule toxine, il est désormais connu que ces microorganismes sont capables d’en synthétiser un grand nombre qu’il conviendrait de mieux prendre en compte dans le futur. C’est pourquoi, dans le but de mieux connaître le potentiel toxique des cyanobactéries, ma thèse s'applique, par des études sur leur génome et par une approche de chimie, à caractériser les gènes impliqués dans la synthèse de ces métabolites ainsi que les métabolites produits par ces gènes, à déterminer sur des souches de culture et dans des échantillons naturels provenant de plans d’eau d’Ile de France quel est le potentiel de production de ces métabolites et à mieux comprendre les facteurs environnementaux qui favorisent cette production. Deux équipes de Paris (Pasteur et iEES) sont associées sur ce travail qui implique également des collaborations étrangères. S'il est désormais bien connu qu'une part importante du métabolisme des cyanobactéries qui sont des microorganismes photosynthétiques, est régulée en fonction des phases de lumière et d'obscurité, les connaissances disponibles sur la synthèse des métabolites secondaires sont en revanche beaucoup plus limitées. Ces métabolites ont pourtant un double intérêt puisque certains sont toxiques pour l'Homme alors que d'autres ont un intérêt pharmaceutique potentiel. Leur synthèse repose sur l'expression de clusters de gènes pouvant être de très grande taille (jusqu’à 100 kb par région).

We have described recently a novel mechanism of regulation combining phase variation and attenuation of two pilus operons in Streptococcus gallolyticus . Phase variation occurs  by single-strand mispairing during replication due to the presence of repeats in the leader peptide located immediately upstream of the pilus operon. We wonder if the same mechanism is applicable to other bacterial genes.

Increasing evidence indicates that nucleoid spatiotemporal organization is crucial for bacterial physiology since these microorganism lack a compartmentalized nucleus. However, it is still unclear how gene order within the chromosome can influence cell physiology. In silico approaches have shown that genes involved in transcription and translation processes, in particular ribosomal protein (RP) genes, tend to be located near the replication origin (oriC) in fast-growing bacteria suggesting that such a positional bias might be an evolutionarily conserved growth-optimization strategy. Recently we systematically relocated a locus containing half of ribosomal protein genes (S10) to different genomic positions in Vibrio cholerae. These experiments revealed drastic differences in growth rate and infectivity within this isogenic strain set. We showed that genomic positioning of ribosomal protein genes is crucial for physiology by providing replication-dependent higher dosage in fast growing conditions. Therefore it might play a key role in genome evolution of bacterial species. We aim at observing how the genomic positioning of these genes would influence the evolution of Vibrio cholerae. To gain insight into the evolutionary consequences of relocating RP genes, we let evolve either the wild type or the most affected strains for 1000 generations in fast-growing conditions. NGS will be performed and analyzedon the evolved populations to understand the genetic changes responsible of the observed phenotypic changes.

The PIBnet initiative is a joint effort by 15 National Reference Centers (NRC), 8 Collaborative Centers of World Health Organization, the Collection de l’Institut Pasteur & Cyanobacteria collection and the CIBU to modernize their activities, including collection management and microbial characterization approaches and technologies. Within this large concerted effort, a priority is to promote whole genome sequencing (WGS) as the major characterization approach of microbial agents for surveillance and outbreak investigation.   Our ambition is to have shifted to WGS as a routine strain characterization method for epidemiological surveillance and outbreak investigation in the Institut Pasteur at the end of 2016. The target volume is 10,000 genomes a year. On the bioinformatics level, this requires implementing fast data treatment tools, databases, genotyping schemes and methods to extract medically relevant information from genomic sequences (resistome, virulome).

Horizontal gene transfer (HGT) is a major driving force of bacterial diversification. For mycobacteria, a special type of HGT was described in Mycobacterium smegmatis which is linked to distributive conjugal transfer (Gray et al., PLoS Biology, 2013). In the current project we are trying to reproduce the results and explore the process.

La PF Transcriptome et Epigenome développe des projets de séquençage à haut débit (collaboration et service) avec des équipes du Campus. Ceux-ci couvrent l'ensemble des thématiques du campus ainsi qu'une large gamme d'organismes (des virus aux mammifères). La plate-forme exerce des activités de biologie humide (construction des librairies et séquençage) et de biologie sèche (analyse bioinformatiques et statistiques). La personne mise a disposition interagira étroitement avec les autres bioinformaticiens du pôle BioMics et du Hub. Ses activités concerneront notamment: - La participation à la conception et à la mise en place des projets avec les équipes demandeuses, la prise en charge des analyses et le reporting aux utilisateurs - La mise en place d'un workflow d'analyse bioinformatique des données de transcriptome /épigénome en étroite collaboration avec le C3BI, la DSI et les autres bioinformaticiens du pole. Ce workflow permettra le contrôle qualité des données, leur prétraitement, le mapping des séquences sur les génomes/transcriptomes de réference, et le comptage des reads pour les différents éléments de l'annotation - L'adaptation du workflow d'analyse aux questions biologiques et aux organismes étudiés dans le cadre des activités de la PF - L'activité de veille technologique et bibliographique (test et validation de nouveaux outils d'analyse, updates d'outils existants...) - La mise en place et le développement d'outils d'analyse adaptés aux futurs projets de la PF: single cell RNAseq, métatranscriptome, ChIPseq, analyse des isoformes de splicing.. Ceci se fera notamment via la réalisation d'analyses dédiées avec certains utilisateurs. Les outils mis en place et validés dans ce cadre seront ensuite utilisés pour l'ensemble des projets. - L'activité de communication et de formation (participation aux réunions du consortium France Génomique,formation permanente à l' Institut Pasteur… - la participation a d autres projets du Pole BioMics (selon disponibilité) Bernd Jagla, qui était le bioinformaticien de la plateforme a rejoint le Hub au 1er janvier 2016. Rachel Legendre est mise a disposition depuis le 2 novembre 2015 et remplace Bernd Jagla. Je souhaite que Rachel Legendre soit mise à disposition de la plateforme pour une durée d'au moins 2 ans.

The dramatic increase in bacterial resistance to antibiotics, particularly of Gram-negative bacteria, poses an immediate threat to our health system. The main driver of this trend is the impact that antibiotics, including b-lactams, exercise on intestinal commensal flora of humans and animals by selecting resistant strains. The intestinal microbiota, with its large spectrum of bacterial populations, density and diversity, can be considered the epicentre of the emergence of resistance. The presence of a large community of phages, bacteria’s viruses, called phageome, able of performing gene transfer between bacteria, raised the question of their role as a reservoir of genes entailing resistance. This project has two objectives (i) to study the role of human stools’s phages in the spread of antibiotic resistant genes with a selection pressure and (ii) to gain insights into the fundamental ecology and biology of phages in the human gut over a time series analysis.

Human macrophages are the main cell target of Mycobacterium tuberculosis (Mtb), the etiologic agent of tuberculosis. Once phagocytosed, bacilli escape bactericidal functions of macrophages and they multiply inside the cell. Understanding interactions between bacilli and human phagocytes is primordial to develop new strategies to combat tuberculosis. We propose a project aiming at deciphering cell-cell communications between infected cells and non-infected cells. We will use the transcriptomic and the proteomic approaches to discriminate the global response of these differents sub-populations. To our knowledge, this work represents the first study that combines two different levels for the identification of a specific response of infected-cells and neighboring non-infected cells. This study would determine cellular markers of a Mtb signature.

Comparative genomics approaches in microbiology now use thousands of genomes to analyze a given species in different environmental or medical contexts. By collecting and comparing these genomic sequences, many  studies are focusing on  the overall gene content of a species (i.e. the pan-genome) to understand their evolution in terms of core and accessory parts. Variable regions are of primary importance to understand the adaptive potential of bacteria and contain genomic regions that are exchanged between strains by horizontal gene transfer (i.e. the mobilome). As recently suggested (Chan et al., Genome Biology 2015), a consensus representation of multiple genomes would provide a better analysis framework than using individual reference genomes. Here, we propose to extend this concept by giving it a formal mathematical representation using a graph model and by applying statistical methods to cluster gene families.

Currently there is increased focus for developing novel antibacterial strategies. The demand is driven by the rise in antibiotic resistance bacteria and many Gram-negative bacteria are on the list of increasingly drug resistant agents. A major target of successful antibiotics is the bacterial cell wall. The target of these drugs is often defined but what is much less understood is the off-target impact of these very important antibiotics. We designed and executed a mutli-omics strategy centered on the Gram-negative pathogen H. pylori. Our goal is to identify potential 'therapeutically susceptible' pathways associated with the physiological response to cell wall stress.

The genome of C. tetani contains a chromosome of approximately 2,8Mb and a large size plasmid (74 kbp) harboring the tetanus-toxin gene. The genome of the strain E88 was sequenced and annotated (PNAS 2003, 100:1316-1321). We have sequenced and performed a first comparison of the genomes of three additional strains (Res Microbiol 2015, 166:326-331). Fourteen additional C. tetani strains were sequenced including historical strains (1952-1968) and recent French clinical isolates. We have the raw data obtained by Illumina sequencing. Sequence comparaison of chromosome and plasmid will be done. For this, in a first time the assembly of sequence read of each strain will be done, in a second time a comparaison of chromosome and the plasmid of these 14 strains by BLAST approach will be made. Finally, a phylogenetic tree will be generated allowing us to see the evolution of this bacteria.

We are comparing the bacterial communities of domestic and sylvatic  breeding sites and midguts of Aedes aegypti collected in Gabon.

An experiment of RNAseq was performed in triplicate with the strain A of Clostridium tetani in TGY (low production of toxin) and MS (high production of toxin) at 24 and 48 h of culture.  This RNAseq was performed in the Pasteur platform PF2. Different comparisons were performed: MS-48h vs MS-24h, TGY-48h vs TGY-24h, TGY-24h vs MS-24h and TGY-48h vs MS-48h. Excel files with differentially expressed genes were provided. For each comparison there are three excel files: complete.xls (contains results for all features), up.xls (contain results for significantly up-regulated features. Features are ordered from de most significant adjusted p-value to the less significant one) and down.xls  (contain results for significantly down-regulated features. Features are ordered from de most significant adjusted p-value to the less significant one). We would like to perform GO term enrichment analysis on the set of genes showing differential expression patterns in the considered contrasts. State of art tools to identify functional enrichments (e.g. DAVID knowledge) do not recognize Clostridium tetani protein and gene identifiers. One possibility is that such tools do not include Clostridium tetani entries in their databases.  The aim of this project is to develop an alternative approach to carry out the functional enrichment analysis on the differentially expressed genes.

Whooping cough is a vaccine-preventable disease due to Bordetella pertussis. Even if vaccination has allowed the control of the disease, isolates are still circulating and cyclic increases of incidence are observed every 3 to 5 years even in vaccinated countries. Most developed countries now use acellular vaccines containing 3 to 5 vaccine antigens (pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (PRN) fimbrial proteins (FIM2/FIM3)) that have replaced whole cell vaccines. In regions vaccinating with acellular vaccines with a high coverage, isolates no more producing some vaccine antigens (mainly PRN) have been reported in the last years.   Bordetella pertussis reference genome has been fully annotated in 2003 by the Sanger Institute. Analysis and comparison of different B.pertussis genomic sequences showed that circulating B.pertussis isolates differ from vaccine and reference strains. Genome evolution is characterized by gene deletions, antigenic divergences, SNP accumulations…Recent genomic analysis gathering isolates from different countries showed that the worldwide B. pertussis population has evolved in the last 60 years,. Gene categories under selection were identified underlying that Bvg-activated genes and genes coding for surface-exposed proteins were important for adaptation. However these analyses concerned only overall vaccine antigen producing isolates.   The PTMMH Unit includes the National Center of reference for Bordetellosis. In the last years some particular B.pertussis French isolates no more producing PRN but also FHA or PT have been collected, analyzed and sequenced. We would like to further analyze these genomic data with a focus on the vaccine antigen deficient isolates through a SNP-based comparison of these isolates vs co-circulating isolates producing all vaccine antigens and vs a reference strain.

The gastrointestinal tract of humans is colonized by hundreds of microbial species, - bacteria, archaebacterial, fungi, protozoa and viruses -, collectively named the gut microbiome. The intestinal commensal bacteria have an important role in metabolic processes and contribute to colonization resistance against intestinal pathogens. Fungi are usually considered to be a minor component of the global microbiome. However, the mycobiome (fungal component of the entire microbiome) has been in fact little studied particularly with regards to its relationships with the other components of the microbiome. It seems however that fungi can be important players of the microbiome because some fungal species are able to proliferate in response to diet or during dysbiosis due to antibiotic treatment or gut inflammation. Consensus approaches to explore mycobiome together with other components of the mycobiome are still lacking. In this context the primary goal of our project will be to determine the best means to analyze bacterial and fungal microbiome concomitantly, using an identical technical procedure. We will evaluate the effectiveness of different methods for: 1) sample conservation; 2) DNA extraction; 3) mapping fungal and bacterial databases. The best procedure then will be used on samples from different studies to analyze interactions and respective dynamics of fungal and bacterial microbiome in different clinical settings.

Recently 6 strains of Leptospira kirschneri ser grippotyphosa have been sequenced, assembled and annotated. These strains possess 99% genome similarity, but their provenance, virulence and growth characteristics remains different. We would like analyze the SNP of each strain using the SynTView/SNPView tool.  

Over the past three decades Listeria has become a model organism for host-pathogen interactions, leading to critical discoveries in a broad range of fields including virulence-factor regulation, cell biology, and bacterial pathophysiology. More recently, the number of Listeria “omics” data produced has increased exponentially, not only in term of number, but also in term of heterogeneity of data. There are now more than 40 published Listeria genomes, around 400 different transcriptomics data and 10 proteomics studies available. The capacity to analyze these data through a systems biology approach and generate tools for biologists to analyze these data themselves is a challenge for bioinformaticians. To tackle these challenges we are developing a web-based platform named Listeriomics which integrates different type of tools for “omics” data manipulation, the two most important being: 1) a genome viewer for displaying gene expression array, tiling array, and RNASeq data along with proteomics and genomics data. 2) An expression atlas, which is a query based tool which connects every genomics elements (genes, smallRNAs, antisenseRNAs) to the most relevant “omics” data. Our platform integrates already all genomics, and transcriptomics data ever published on Listeria and will thus allow biologists to analyze dynamically all these data, and bioinformaticians to have a central database for network analysis. Finally, it has been used already several times in our laboratory for different types of studies, including transcriptomics analysis in different biological conditions, and whole genome analysis of Listeria proteins N-termini. This project is funded by an ANR Investissement d'avenir: BACNET  10-BINF-02-01

In the context of the Swiss consortium InfectX (www.infectx.ch), Javier PIZARRO-CERDA previously performed siRNA, microRNA, drug screens and proteomic analyses to investigate signaling pathways modulating invasion of host cells by the bacterial pathogen Listeria monocytogenes. In a first consortium study, based on results from drug and siRNA screens targeting the human kinome, we identified major kinases which up- or down-regulate cell invasion by L. monocytogenes and by 7 additional bacterial and viral pathogens (Rämö et al. 2014). Subsequently, a siRNA genome-wide screen allowed us to revisit and redefine the role of cytoskeletal complexes required for L. monocytogenes cellular invasion and actin-based motility (Kühbacher et al. 2015). Applying a proteomic ‘surfaceome’ analysis, we also revealed that late endosomal compartments are recruited to L. monocytogenes infection foci to promote invasion (Kühbacher et al. Submitted). More recently, we have started the analysis of a microRNA screen which highlights novel gene clusters associated to regulation of phosphoinositide metabolism during L. monocytogenes cell entry (Kühbacher et al. Unpublished Results). These different projects have generated vast amounts of data that have been until now only independently analyzed. However, this information can now be exploited from a systems biology perspective to identify hidden connections between relevant signaling cascades and gene networks which may highlight novel cellular functions exploited by pathogens in the context of infection. The team of Benno SCHWIKOWSKI will perform two types of analysis on the data generated by Javier PIZARRO-CERDA. In both cases, p-values will be aggregated across gene sets using suitable statistical approaches. We will then

• Pathway-based analysis. This type of analysis considers genes in sets that have been recognized to operate together to perform certain biological functions (e.g.,

A large fraction of diversity of the Archaea is still poorly explored. We are targeting environmental samples to extract genomic data of archaeal lineages of specific interest from an evolutionary point of view. We will probe available sequence data from public environmental metagenomics databases to identify specific lineages. In parallel, we will produce our own data from selected environmental samples containing these lineages. These data will allow filling up poorly explored branches of the tree of Archaea and bring important information on the metabolic diversity and adaptation to various environmental conditions, including the human microbiome.  

  Shigella is an enteroinvasive bacterium that induces bacillary dysentery. It invades human intestinal epithelial cells causing the inflammatory destruction of the colonic epithelium. Our previous work reported that Shigella inhibits the secretion of its host cell (Mounier et al Cell Host Microbes 2012) via several virulent proteins injected by the bacterium such as IpaJ and VirA. These two effectors may have redundant action. Thus, to address the effect of Shigella on the secretome of its host cell and in particular define the precise action of IpaJ and VirA, we conducted a mass spectrometry (MS) analysis on apical (A) and basal (B) secretion of polarized infected human intestinal cells using several strains: wild type (WT), avirulent strain (mxiD) and mutated strains either on virA, ipaJ or both (virAipaJ) and compared to non-infected cells (NI). We have in total 6 infection conditions and we collected apical and basal secretion medium (total 12 MS data). Most of the conditions were done in triplicate. We have now these quantitative MS data (excel file) that gave between 300 (basal secretion) to 1000 proteins (apical secretion) secreted differently among the different conditions. We need your collaboration to analyze our data to: Check whether our protein candidates are in databases of secreted factors Obtain protein clusters of our hits among the 6 conditions used (12 datasets)

We're interested in the production of a toxin by Klebsiella pneumoniae. We have a mutant unable to produce this toxin, and would like to identify the mutation responsible of this inability.

The first two cases in France of botulism due to Clostridium baratii type F were identified in November 2014, in the same family. Both cases required prolonged respiratory assistance. One of the cases had extremely high toxin serum levels and remained paralysed for two weeks. Investigations strongly supported the hypothesis of a common exposure during a family meal with high level contamination of the source. However, all analyses of leftover food remained negative. Clostridium baratii was isolated from stool specimens from the two patients. A second cluster of three cases of food-borne botulism due to Clostridium baratii type F occurred in France in August 2015. All cases required respiratory assistance. Consumption of a Bolognese sauce at the same restaurant was the likely source of contamination. Clostridium baratii was isolated both from stool specimens from the three patients and ground meat used to prepare the sauce. This is the second episode reported in France caused by this rare pathogen. One strain from the first cluster and four from the second one have been sequenced (Illumina technology). A complete genome of a C. baratii strain (Sullivan) isolated from adult stool in 2007 in New York is available in Genbank (chromosome: CP006905; plasmid: CP006906).

One project of our laboratory is to characterize the function of small proteins specifically expressed in nongrowing Salmonella cells under the tight control of SigmaS.  Our current works focus on small proteins secreted or targeted to the membrane since their characterization might reveal novel aspects of membrane functions and secretion in persistent bacteria, including pathogens. The proposed project is an extension of a former project on the phylogenetic distribution of the small orfs, and aims at analyzing the genomic context of orthologs.

Recherche de SNP chez une souche de leptospira biflexa devenue résistante à un bactériophage.

Mycobacterium tuberculosis is an extremely successful, aerosol-transmitted human pathogen, thought to have evolved from a Mycobacterium canettii-like progenitor. In contrast, extant M. canettii strains are rare, genetically diverse and geographically restricted mycobacteria of only marginal epidemiological importance. Comparative genome studies of several Mycobacterium canettii strains previously identified genetic events that contribute to the contrasting evolutionary success observed between M. canettii and M. tuberculosis strains. In this project we now focus on the genetic factors required for the emergence of highly specialised, virulent tuberculosis bacilli.

We submitted an article about the diversity of Clostridium botulinum strains based on MLST analysis. One reviewer of the article asked further study of our NGS data.

Label free quantification of proteins after the infection with M. tuberculosis. Macrophages isolated from seven patients were used in this study. Four conditions were compared.

Context. Bacteria of the genus Shigella and strains of entero-invasive Escherichia coli (EIEC) are responsible of bacillary dysentery (shigellosis) in humans. Although (very) closely related to E. coli, the genus Shigella is divided in four "species": S. boydii, S. dysenteriae, S. flexneri and S. sonnei. Most virulence determinants enabling these bacteria to enter into and disseminate within epithelial cells are encoded by a 200-kb virulence plasmid (VP). The first complete sequence of a VP (pWR100 from a S. flexneri strain of serotype 5a) was determined by our laboratory in 2000. The VP contains genes of different origins, as attested by their G+C content ranging from 30 to 60%, traces of four plasmids and a large numbers of various insertions sequences (IS) representing 30-40% of the total sequence (Buchrieser et al., 2000). In addition to IS sequences, the VP carries members of several multigene families (exhibiting over 90% identity). Such repeated sequences are potentially prone to recombination (allelic exchange, gene conversion) and deletion. Based on the analysis of three genes carried by the VP, it has been proposed that, depending of the species / phylogenetic group, there are two forms of the VP (pInvA & pInvB) that were acquired independently in different original E. coli strains. General questions. What are the architectures of the VP from different phylogenetic groups and how different are pInvA and pInvB ? Which genes are conserved in all VP and which genes are unique to some VP ? Did recombinations occur and, if so, where and when ? To answer these questions, a comparative analysis of the genetic organization and gene conservation among the VP from different phylogenetic groups of Shigella/EIEC has been undertaken using the available complete (or presented as such) sequences of 15 VP, including three members for each of five phylogenetic groups (S. boydii, S. dysenteriae 1, S. flexneri, S. sonnei and EIEC).

Listeria monocytogenes is a gram-positive bacterium responsible for the food-borne disease listeriosis. This pathogen can invade and replicate in the cytoplasm of both macrophages and non-professional phagocytes. In order to better characterize the host response to Listeria, we are using microarrays to identify genes and cytokines up or downregulated during infection.

Tuberculosis (TB) still remains a major public health problem with estimated 9 million incident cases and 1.5 million deaths in 2014 (WHO, Global Tuberculosis Report 2015). More worrisome is the emergence of multi drug resistance (MDR), or even extensively resistant (XDR) M. tuberculosis strains worldwide. The standardized treatment of pan-susceptible tuberculosis is the administration of two antibiotics (rifampicin and isoniazid) for six months, accompanied by two additional antibiotics (pyrazinamid and ethambutol) for the first two months. Although very efficacious, this treatment is very demanding due to the duration and the possible side effects. The treatment of MDR-TB is less standardized, with more toxic and poorly tolerated drugs, resulting in lower cure rates. Therefore, we need not only more molecules with antimycobacterial activity, but also, we urgently need new strategies to increase our therapeutic arsenal for treating MDR-TB. Only three new drugs, bedaquiline, delamanid and PA-824 have been tested in phase2/3 clinical trials.

In this context, the european funded project NAREB has been created. It brings together 14 partners from 8 EU Member and Associated States, and it aims to (i) screen different combinations of antibiotic drugs with nano-carriers (lipid, polymeric, biopolymeric) with and without targeting ligands, (ii) coload antibiotics in order to develop innovative therapeutic combination therapies (iii) test in vitro and in vivo the best therapeutic combinations. In particular, we will analyze more in-depth the effect of bedaquilin, new TB drugs and nano-carriers on the host/bacterial transcriptome using RNAseq.

Microbial discovery remains a challenging task for which there are a lot of unmet medical and public health needs. Deep sequencing has profoundly modified this field, which can be summarized in two questions : i) which pathogens or association of pathogens are associated with diseases of unknown etiology and ii) among microbes infecting animal (including arthropod) reservoirs, which ones are able to infect large vertebrates, including humans. We are currently addressing these two questions and our current request comes with the willingness for Institut Pasteur to increase its contribution and visibility of this thematic, in particular in relation with hospitals and the Institut Pasteur International network (IPIN).  We expect to identify new microbes associated with human diseases, and this is expected to pave the way for basic research programs focusing on virulence mechanisms and host specificity, and will also lead to phylogenetic and epidemiological studies (frequency of host infection, mode of transmission etc...), as well as the development of improved diagnostic tests for human infections. Our objective is also to contribute to the efforts of Institut Pasteur in the field of infectious diseases, by building a pipeline, from sample to microbial identification, able to manage large cohorts of samples. This project is currently supported by the LABEX IBEID and the CITECH, and critically requires a bioIT support, justifying this application. Partners include different hospitals including Necker-Enfants malades University Hospital regarding patients with progressive disease, different IPIN laboratories, as well as INRA and CIRAD regarding animal/arthropod reservoirs.

This project is intended to explore the novel protein interactions that are involved in the protein folding in cyanobacteria. Slr0286 was previously identified as a protein interacting with the D2 protein of photosystem 2 and affecting its functional assembly and stability in Synechocystis sp. PCC6803. The gene that encodes this protein appears to be in one operon with slr0285 in all strains where these two genes are found. This may suggest the functional relationship between the products of these genes. We would like to explore the question of whether these genes co-evolved and whether there could be an evidence of interaction between Slr0285 and Slr0286.

As a part of BIRDY program (http://www.charliproject.org/), this project aims to study the microbiome composition and its dynamics in early infancy in Madagascar. It will provide genomic knowledge on antibiotic resistant strains and resistance genes circulating in this island. It will identify factors influencing the outgrowth of pathogenic bacteria, including ESBL-PE and decipher the role of the gut microbiome. The developed comprehensive modeling framework will be easily adaptable to other epidemiological questions related to the impact of any human intervention on the gut microbiome and of other environments such as skin, nose or urogenital tract. This project will contribute to the transfer of expertise in genomics and bioinformatics to the IP Madagascar partners.

One of the best models for the study of bacteria-host interactions is Listeria monocytogenes. One interesting facet of this bacterium is its ability to modify host chromatin. Recently, we have shown that Listeria causes a drastic deacetylation of histone H3 on lysine 18 (H3K18dc). Interestingly, to impose this modification, Listeria highjacks previously undescribed host machinery: the host protein sirtuin 2 (SIRT2) is relocalized to the nucleus where it causes genes repression during infection. SIRT2 is a NAD-dependent deacetylase that has been implicated in the regulation of complex processes such as aging and cancer. This protein had been mainly studied in the cytoplasm, and although SIRT2 had been show to shuttle between the cytoplasm and the nucleus, the mechanism and its biological role remained unknown.        In order to further characterize the role of SIRT2 during infection and identify all the genes at which it is recruited, we are performing ChIP-seq analysis. These studies are expected to bring new insights into the function and regulation of SIRT2 by characterizing this new phosphorylation site.

The aim of the project is to search for the effects of hepatic inflammation on microbiota.

Bacterial strains used for quality control (e. g. fertility and viability controls) are recommended in different ISO norms. Each strain is at least deposited in two different collections. So, equivalent strains are found in different collections. Their preservation is generally performed by freeze-drying. As control strains, they are much distributed, thereby, new freeze-dried batches have been done in the course of time. The submitted project aims to see what impact has the long-term strain preservation at the genomic level and if control strains preserved in two different collections can always be considered as equivalent.

We are interested to look at evolution of bacteria in presence of bacteriophages within the gastrointestinal tract of animals.    

Bacillus cereus is ubiquitous in nature, and while most isolates appear to be harmless, some are associated with food-borne illnesses, periodontal diseases, and more serious infections. Moreover, emerging B. cereus strains that cause anthrax-like disease have been isolated in Cameroon and Côte d’Ivoire. These strains are particular, because although they belong to the B. cereus species genetically speaking, they harbor two plasmids, pBCXO1 and pBCOX2, that are very similar to the pOX1 and pOX2 plasmids of Bacillus anthracis that encode the toxins and the polyglutamate capsule, respectively. Around one hundred strains of Bacillus cereus from different origins (environment, clinical and food) deposited at the Collection de l’Institut Pasteur (CIP)  are studied and whole genome sequencing has been performed in order to characterize the pathogenicity of the strains by looking for virulence genes and by comparing the strains (genes of interest), depending on their origin.

Thanks to RNA-Seq experiments we identified  a new orphan DNA methylase (not associated with a restriction enzyme) that is highly upregulated in the presence of low concentrations of aminoglycosides in V. cholerae. The results allow us to consider a differential DNA methylation profile depending on the environment (with or without antibiotics), which can possibly correspond to a novel epigenetic control of the response.

Rapid and accurate identification of microorganisms is a prerequisite for appropriate patient care and infection control. In the last decade, Mass Spectrometry (MS) has revolutionized the field of clinical microbiology with the introduction of MALDI-TOF for rapid microbial identification. However, MALDI-TOF MS suffers from important limitations. Some bacteria remain difficult to identify, either because they do not give a specific profile or because the database lacks the appropriate reference. In addition, the discriminatory power of the technique is often insufficient for reliably differentiating sub-species within species or clones within sub-species. More importantly, virulence or resistance determinants cannot be characterized, which is a severe obstacle for appropriate patient care and antibiotics prescription in hospitals. In recent years, proteomics approaches have been increasingly used to study host-pathogen interactions. State-of-the-art bottom-up approaches rely on the enzymatic digestion of proteins and LC-MS/MS analysis of peptides. In contrast, top-down proteomics is an emerging technology based on the analysis of intact proteins by high-resolution mass spectrometry. The major advantage of top-down proteomics is its ability to address protein variations and characterize proteoforms arising from alternative splicing, allelic variation, or post-translational modification. We have recently set-up a robust top-down proteomics platform for the analysis of intact bacterial proteomes. Our final objective is to use this platform to better characterize bacterial pathogens in a clinical context, but a major requirement to achieve this goal is to build up accurate bacterial proteoform databases.  

Integrons drive the spread of antibiotic resistance genes in bacterial populations. While their role is widely known (integron+antibiotic+resistance in PubMed gives > 1700 hits), there was no software available to identify integrons and their different components. We have made integronFinder (with Bertrand Néron) for this (Cury, NAR, 16). We would like to make improvements to IntegronFinder:

• Unit tests to facilitate the development of the tool. Especially since Jean Cury (the main author) will leave the lab in the summer of 2017.
• Add the possibility of using multi-fasta as input.

Extracellular capsules constitute the outermost layer of some bacteria and establish the first contact between the cell and its environment. They are major virulence factors involved, amongst other, in antibiotic tolerance and immune escape. Bacterial capsules are also known to mediate unspecific cell-to-cell interactions between and across species and affect population structure and dynamics. Despite the great number of studies characterizing capsule diversity and their role during infection in a few model species, most evolutionary and ecological questions have yet to be adressed. Furthermore, there is no tool to identify and annotate capsule systems across all prokaryotic genomes. We have built such a tool and would like to make it available.

Anopheles mosquitoes are the vectors of Plasmodium parasites, the etiological agents of malaria in humans. In Anopheles gambiae, a major vector in Africa, parasite transmission is largely under genetic control. We have previously shown that a gene family is implicated in the immune control of the parasite in this vector. The response of the family members is pathogen-specific, with one controlling P. falciparum infection and the other controlling rodent parasites. Recently, the genome of Anopheles stephensi, the major Asian vector, has been sequenced and, in this species, there is only one gene. Knocking down this gene reduced lifespan of A. stephensi and antibiotic treatment restores a normal longevity, suggesting the implication of the gut microbiota. Therefore, we conducted a metagenomic analysis in order to identify the bacteria responsible for the shorten of the mosquito lifespan.

Shigella species and E. coli are very closely related bacteria belonging to the Enterobacteriaceae family. Phenotypically they are very similar and genotypically they could be considered the same species. The differentiation of Shigella species from E. coli is a significant diagnostic challenge for the clinical microbiology laboratories. They increasingly use maldi-tof mass spectrometry-based microbial identification systems but the latter are currently not able to distinguish these species. As the National Reference Center of E. coli and Shigella, we possess an exhaustive and extensive collection of strains (all serotypes and a wide range of phenotypic profils). We want to use our unique strain collection to propose a highly performant approach for differentiating these bacterial species by MALDI-TOF MS. Success of this study would be incredibly valuable for making an immediate impact on the clinical microbiology diagnosis.

Nous avons pu montrer grâce au projet de recherche clinique VOYAG’R (PHRC AOR 11101- IP Pr S. Matheron) que les voyages dans une zone tropicale constituaient un risque d’acquérir une Entérobactérie multi-résistante (EMR). Pendant 15 mois, la présence d’EMR a été recherchée chez 574 sujets avant et après leur voyage en zone tropicale. Les voyageurs porteurs au retour étaient suivis sur une période de 12 mois (1, 2, 3, 6 et 12 mois ou jusqu’à négativation). Au cours de leur séjour, la moitié des voyageurs ont acquis une EMR. Nous avons également observé que trois mois après leur retour, 95% des voyageurs avaient éliminé leur EMR. Cependant 11 sujets ont conservé leur(s) souche(s) d’EMR pendant au moins 6 mois. Ces souches persistantes pourraient avoir des capacités pour perdurer au sein du tube digestif

Pathogen leptospires are responsible for the zoonotic disease leptospirosis. This neglected but emerging infectious disease has a worldwide distribution and affects people from developing countries, mostly under tropical areas. The clinical manifestations of this infection range from a febrile state to a severe life-threatening form characterized by multiple organ hemorrhages. More than one million cases of leptospirosis are currently reported annually in the word, with 10% of mortality. During infection, Leptospira are confronted with dramatic adverse environmental changes such as deadly reactive oxygen species (ROS). Defenses against ROS, e.g. peroxidase activity, are crucial for Leptospira virulence. These defense mechanisms are controlled by PerR (Peroxide stress Regulator), which represses peroxidase-encoding genes. We study the role of PerR regulators in Leptospira virulence and adaptation to oxidative stress.

We are studying mutants of L. interrogans obtained after random mutagenesis (M58) along with complemented mutant strain (C5M58), constructed using a secondary random mutagenesis. The M58 mutant was found non virulent in gerbils and mice, but the C5M58 strain showing restored expression of the protein, is also non virulent. We have another mutant strain (M1901) in the same gene that retained its virulence, which is the expected phenotype. We are interested in findings SNPs present in both mutant M58 and complemented  C5M58 strains that are absent from the parental L495 and M1901. This approach  could give hints about the gene(s) involved in the loss of virulence.

Linked with the project #7283 managed by Thomas Bigot, this proposal aims to detect antibiotic resistance genes in whole-genome sequence data of the bacteria deposited and stored at CIP. The CARD library (http://arpcard.mcmaster.ca) would be used to screen for common acquired resistance genes. Detection of point mutations in house-keeping genes and/or transporters would require specific queries from a fasta file continuously implemented by myself.

The microbiota of the gastrointestinal tract is a diverse mixture different species and strains of bacteria. We aim to identify regions of dissimilarity between two different bacterial strains to be able to quantitate their relative abundance and thus obtain information about their ability to cohabitate a common environment. In addition, we are interested in assessing the surface localised protein repertoir of specific species through a combination bioinformatic analysis and proteomics.

Extracellular capsules constitute the outermost layer of some bacteria and establish the first contact between the cell and its environment. They are major virulence factors involved, amongst other, in antibiotic tolerance and immune escape. Bacterial capsules are also known to mediate unspecific cell-to-cell interactions between and across species and affect population structure and dynamics. Despite the great number of studies characterizing capsule diversity and their role during infection in a few model species, most evolutionary and ecological questions have yet to be adressed. Furthermore, there is no tool to identify and annotate capsule systems across all prokaryotic genomes. Our previous project led to the installation of our tool on the Galaxy Server. The goal now is to put the data of our survey (>2000 genomes) for the capsule available to the community.

We are analyzing a Listeria protein secreted in the supernatant. From cells transfected with this protein, after crosslinking, we have isolated RNA and found the protein in the RNA fraction. In addition, the protein binds several splicing factors in RNA dependent manner. Furthemore, the protein localizes to the nucleus. In this project, we have isolated the protein from the supernatant and from bacterial extract after growth in BHI. We have extracted the RNA from the supernatant fraction containing the protein and from the bacterial extract containing the protein. We want to alalyze the RNA in these different fractions.

The adenylate cyclase (CyaA) produced by B. pertussis, the causative agent of whooping cough, is one of the major virulence factors of this organism. CyaA plays an important role in the early stages of respiratory tract colonization by B. pertussis. This toxin uses an original intoxication mechanism: secreted by the virulent bacteria, it is able to invade eukaryotic target cells through a unique but poorly understood mechanism that involves a direct translocation of the catalytic domain across the plasma membrane. CyaA is a 1706-residue long protein organized in a modular fashion. The ATP-cyclizing, calmodulin-activated, catalytic domain (ACD) is located in the 400 amino-terminal residues. Once secreted by the bacteria, the toxin binds calcium in the extracellular milieu and refolds into a functional state. Then, CyaA translocates its catalytic domain directly across the plasma membrane from the extracellular medium to the host cell cytoplasm where, upon activation by endogenous calmodulin, it increases the concentration of cAMP to supraphysiological levels that ultimately leads to the cell death. Recently, we succeeded to refold CyaA in a stable and monomeric form that is fully folded and functional (at variance with all prior procedures in which the polypeptides were largely aggregated upon urea removal). Both calcium and molecular confinement are mandatory to produce the monomeric state and CyaA acylation also strongly contributes to the refolding process. We further show that the monomeric preparation displayed hemolytic and cytotoxic activities suggesting that the monomer is the genuine, physiologically active form of the toxin. Hence, despite recent advances in the understanding of CyaA, its mechanisms of cell intoxication process, in particular the membrane translocation step, remains poorly understood from a fundamental perspective. The description of the molecular events occurring prior to and during the translocation of the catalytic domain across the lipi

Escherichia coli is one of the major bacterial pathogens that are responsible for numerous nosocomial infections. While most of the E. coli infections are rather related to colonisation of the urinary

Tuberculosis (TB), which is caused by Mycobacterium tuberculosis (MTB), is the deadliest disease due to a single infectious agent. Despite considerable efforts to fight the disease, TB remains a major public health problem. Even more worrying for the future, multidrug resistant (MDR) strains of MTB are continually emerging and about 10% of people with MDR-TB have extensively drug-resistant TB (XDR-TB). Drug-sensitive TB can be cured by a 6-month treatment using 4 antibiotics, but MDR-TB and extensively drug-resistant XDR-TB require treatment for up to 2 years with more toxic and costly second- and third-line drugs. Toxicity of these drugs is well described; it includes hepatotoxicity, liver injury, skin reactions, gastrointestinal and neurological disorders. However how MTB drugs influence the host response to MTB infection has been poorly addressed. The main goal of project is to understand how drugs interact with the host in order to improve the treatment.

Lyme borreliosis is the most common tick-borne disease in the northern hemisphere. In Europe, it is transmitted by Ixodes ticks that carries bacteria belonging to the Borrelia burgdorferi sensu lato complex. Our study was focused on peri-urban forests of Île-de-France. These forests are frequented by many visitors and the risk of exposure to tick bites is high. One of them, the Sénart forest, is located 30 km south of Paris (in the Île-de-France region) and has a large number of visitors (3 million per year in the late 1990s). This forest has the characteristics of being partly invaded by chipmunks (Tamias sibiricus). The chipmunk has been introduced from Eurasia, particularly Siberia, China and Korea. The first individuals were released by their owners at the western end of the Sénart forest, in the 1970s. The northeastern part of the forest was colonized recently. Our current study aims to evaluate the evolution of the infection of Ixodes ricinus by Borrelia burgdorferi sl. by comparing the results obtained during 3 years and to determine the consequences of the proliferation of this non-native rodent species, Tamias sibiricus, on the risk of transmission of Lyme borreliosis. For this purpose, we analyzed the rate of infection and the density of infected ticks during 2008, 2009 and 2011 in several locations of the Sénart forest. These results were compared to those obtained for ticks collected in 2009 in two other peri-urban forests of Île-de-France (Rambouillet and Notre-Dame) that have not yet been colonized by these rodents. The density of nymphs, adults as well as the infected density of nymphs and adults were compared according to several factors: location of tick collection in the forest,  presence or absence of chipmunks, type of vegetation, temperature and humidity.

The present work is to systematically investigate the role of TLRs and NODs in the host defense during C. trachomatis infection using KO animals. The inflammatory cytokines and bacterial burden will be measured using Bio-Plex ELISA kit. C3BI will provide help in the data analysis.

Colon cancer (CRC) is frequent, of bad prognosis, whilst the cost continues to increase. Environmental factors play a role in the majority of sporadic CRC cases. All members of a family share common environment factors and gene determinants. In about 5% of CRC, dominant role of gene is identified as Lynch Syndrome (LS) with mutation in DNA mismatch repair (MMR) genes. Considering the high lifetime risk of developing carcinomas in these individuals, it is relevant to study whether modifiable lifestyle factors can affect the cancer risk. Faecal microbiota that (all bacteria present in the colon) is specific to each individual and highly influenced by environment factors. It boosts CRC development in animal, exerts modulation on inflammation and immunity in the tumour microenvironment and its changes (dysbiosis) is associated with higher CRC risk. It therefore is considered as a mirror of individual “environment-host” interactions. PI of the present project initiated the APHP and EMBL scientific collaboration in 2009 that yielded these results. Fusobacteria (Fu) and particularly, nucelatum animalis and vicentii (FuN) species, could be considered as “bad” bacteria because appeared more prevalent in CRC. We presently whish identifying and quantifying all significant bacteria associated to CRC as community for evaluating predictive values at baseline up to a subsequent occurrence (longitudinal analysis) of high grade dysplasia (HGD), polyps and/or CRC.

Quantitatively understanding the stochastic dynamics of gene expression requires measurements at the level of single cells. A common approach to follow the expression of genes in single cells and in real time is to make use of fluorescent reporter proteins and to record the cells' fluorescence by microscopy. However, this provides only an indirect readout of the biological processes that are of interest such as the regulation mechanisms at the promoter. A possible way to uncover the unobservable biological processes is to infer the hidden dynamics from the available data through the use of mechanistic models of gene expression. The goal of this project is to develop methods for state estimation and parameter inference for such models and to test these methods on real data.

Whole genome sequencing is revolutionizing the surveillance of foodborne and waterborne bacterial pathogens. The speed with which public health laboratories obtain information after the onset of symptoms and the regular sharing of this information between public health laboratories and epidemiologists are critical for the successful use of information to detect outbreaks early and to identify their source. For this purpose, this project aims at providing the most relevant bacterial genomic information in a timely-manner by integrating different validated in silico tools (core genome MLST, CRISPR, O and H molecular serotype, ....) into a single automated analysis pipeline.

Streptococcus agalactiae (GBS) is a gram positive-bacteria which asymptomatically colonize the genital and intestinal tract of healthy women, although the leading cause of bacterial invasive infection

Le génotypage MLST (Multi-Locus Sequence Typing) est une technique standard qui permet une caractérisation génotypique précise et reproductible des souches bactériennes. Elle consiste à déterminer la

Taking advantage of a murine model of controlled microbiota composed of 12 strains, we evaluated the activity of a cocktail of three virulent bacteriophages to target a murine Escherichia coli strain

In this project we study ecological diversification of Klebsiella pneumoniae and closely related species. Using comparative genomics we want to identify the pattern of genome adaptation to different e

We want to automatize the merging of CSV document for data analysis purposes. We've already discussed it with Gael Millot.

The CRBIP, Centre de Ressources Biologiques de l’Institut Pasteur, is a structure created in 2001 that encompasses the Pasteurian culture collections: the CIP (bacteria collection), the PCC (cyanobact

This project is integrated in the analysis of the gut ecosystem of children implicated in the AFRIBIOTA project, a translational project performed within a consortium of researchers and medical doctor

Pathogen leptospires are responsible for the zoonotic disease leptospirosis. This neglected but emerging infectious disease has a worldwide distribution and affects people from developing countries, m

Nous souhaitons analyser les séquences de sept mutant de Mycobacterium marinum générées par l’utilisation de concentrations croissante d’un antibiotique candidat dont nous ne connaissons pas la cible.

Bacteriophages infect bacteria. One bacteriophage can infect several strains. Around the world, many labs have performed spot tests to determine the host range of bacteriophages but this information i

Helicobacter pylori is a Gram-negative pathogen whose infection results in various gastric diseases including gastric cancer in Humans. Current drug therapy against the bacteria involves a combination

A number of mammalian cell types are susceptible to Salmonella Typhimurium infection, including epithelial cells, fibroblasts and macrophages. It has recently been demonstrated that Salmonella display

Streptococcus agalactiae (GBS) is a commensal gram-positive bacteria which asymptomatically colonize the genital and intestinal tract of healthy women. However, GBS is the leading cause of bacterial i

There exists a broad biodiversity inside the Listeria monocytogenes species, which can be summarized by the existence of evolutionary lineages and more than 100 clonal complexes (CCs or clones) based

crispr.pasteur.fr is a website providing resources to visualize CRISPR screen data and design CRISPR experiments in bacteria

Members of the genus Yersinia include environmental as well as pathogenic bacteria. Pathogenic species (Y. pestis, Y. pseudotuberculosis and Y. enterocolitica) have historically been targets for resea

Burkholderia ambifaria bacteria are uiquituos microorganisms present in different environmental sources. Particularly these bacteria have been found to be frequently isolated from rhizospheric soils o

Microbes are prone to rapid changes and they can either exploit or countervail their variation in a context-dependent manner. To this purpose, both genetic diversity and non-genetic phenotypic variati

Our project is focused on the intracellular life of Brucella abortus, the causative agent of bovine brucellosis. B. abortus is a facultative extracellular-intracellular pathogen that upon infection of

Without new treatment development tuberculosis could cause about 70 million deaths by 2050, mostly due to the spread of multidrug-resistant strains. The standard drug regimen still builds on the first

Les cyanobactéries sont des microorganismes qui prolifèrent dans de nombreux plans d’eau et perturbent leurs fonctionnements et leurs usages car elles sont capables de produire des toxines dangereuses pour la santé humaine et animale. Si la réglementation sanitaire est basée, pour l’instant, sur la surveillance d’une seule toxine, il est désormais connu que ces microorganismes sont capables d’en synthétiser un grand nombre qu’il conviendrait de mieux prendre en compte dans le futur. C’est pourquoi, dans le but de mieux connaître le potentiel toxique des cyanobactéries, ma thèse s'applique, par des études sur leur génome et par une approche de chimie, à caractériser les gènes impliqués dans la synthèse de ces métabolites ainsi que les métabolites produits par ces gènes, à déterminer sur des souches de culture et dans des échantillons naturels provenant de plans d’eau d’Ile de France quel est le potentiel de production de ces métabolites et à mieux comprendre les facteurs environnementaux qui favorisent cette production. Deux équipes de Paris (Pasteur et iEES) sont associées sur ce travail qui implique également des collaborations étrangères. S'il est désormais bien connu qu'une part importante du métabolisme des cyanobactéries qui sont des microorganismes photosynthétiques, est régulée en fonction des phases de lumière et d'obscurité, les connaissances disponibles sur la synthèse des métabolites secondaires sont en revanche beaucoup plus limitées. Ces métabolites ont pourtant un double intérêt puisque certains sont toxiques pour l'Homme alors que d'autres ont un intérêt pharmaceutique potentiel. Leur synthèse repose sur l'expression de clusters de gènes pouvant être de très grande taille (jusqu’à 100 kb par région).