Single-cell reporters for pathogen responses to antimicrobial host attacks

Host-pathogen interactions are often heterogeneous involving individual encounters between host and pathogen cells with diverse molecular mechanisms, response networks, and diverging outcomes. Single-cell reporters can identify the various types of interactions and participating pathogen subsets, help to unravel underlying molecular mechanism, and determine individual outcomes and their impact on disease progression. In this review, we discuss reporters-based on fluorescent proteins. We present different types of reporters and their experimental advantages and challenges, and describe how different strategies can interrogate exposure to antimicrobial host mechanism, pathogen response, inflicted damage, and impact on pathogen fitness at the single-cell level. We find many gaps in available tools but also exciting avenues to address these issues

A multiplicative hazard regression model to assess the risk of disease transmission at hospital during community epidemics

<p>Abstract</p> <p>Background</p> <p>During community epidemics, infections may be imported within hospital and transmitted to hospitalized patients. Hospital outbreaks of communicable diseases have been increasingly reported during the last decades and have had significant consequences in terms of patient morbidity, mortality, and associated costs. Quantitative studies are thus needed to estimate the risks of communicable diseases among hospital patients, taking into account the epidemiological process outside, hospital and host-related risk factors of infection and the role of other patients and healthcare workers as sources of infection.</p> <p>Methods</p> <p>We propose a multiplicative hazard regression model to analyze the risk of acquiring a communicable disease by patients at hospital. This model derives from epidemiological data on communicable disease epidemics in the community, hospital ward, patient susceptibility to infection, and exposure of patients to infection at hospital. The model estimates the relative effect of each of these factors on a patient's risk of communicable disease.</p> <p>Results</p> <p>Using individual data on patients and health care workers in a teaching hospital during the 2004-2005 influenza season in Lyon (France), we show the ability of the model to assess the risk of influenza-like illness among hospitalized patients. The significant effects on the risk of influenza-like illness were those of old age, exposure to infectious patients or health care workers, and a stay in a medical care unit.</p> <p>Conclusions</p> <p>The proposed multiplicative hazard regression model could be an interesting epidemiological tool to quantify the risk of communicable disease at hospital during community epidemics and the uncertainty inherent in such quantification. Furthermore, key epidemiological, environmental, host, or exposure factors that influence this risk can be identified.</p

Study of bacterial frataxin CyaY in Escherichia coli

Les protéines à centre Fe-S sont impliquées dans de nombreux processus cellulaires. In vivo, la formation des centres Fe-S est réalisée par des machineries multi-protéiques dont ISC et SUF, conservées chez les eucaryotes et les procaryotes. D’autres composants participent à la formation des centres Fe-S chez les eucaryotes, comme la frataxine (FXN). La FXN est une protéine présente chez l’homme, les plantes, la levure ou encore les bactéries à Gram négatif. Chez les eucaryotes, l’absence de FXN conduit à des phénotypes drastiques comme une accumulation de fer dans la mitochondrie, une diminution drastique de l’activité d’enzymes à centre Fe-S ou encore des dommages oxydatifs. Chez l’homme, un déficit en FXN est responsable d’une maladie neurodégénérative, l’ataxie de Friedreich. A la différence des eucaryotes, chez les procaryotes comme Escherichia coli, l’absence de CyaY, homologue bactérien de la FXN, ne conduit à aucun des phénotypes évoqués ci-dessus.Durant ma thèse, je me suis intéressée au rôle de CyaY chez E. coli. J’ai montré que, in vivo, CyaY favorise la formation des centres Fe-S via la machinerie ISC. Un lien génétique entre CyaY et IscX a également pu être établi, montrant que ces deux protéines participent à la formation des centres Fe-S in vivo. Je me suis ensuite intéressée aux bases moléculaires pouvant expliquer la différence entre les phénotypes liés à l’absence de FXN chez les eucaryotes et les procaryotes. J’ai montré que le résidu 108 de IscU joue un rôle clé pour la dépendance de CyaY. Enfin, pour mieux comprendre le rôle de CyaY chez E. coli, j’ai réalisé une approche globale en caractérisant le transcriptome du mutant ∆cyaY.Fe-S cluster containing proteins are involved in many cellular processes such as respiration, DNA repair or gene regulation. In vivo, Fe-S cluster biogenesis is catalysed by specific protein machineries, ISC and SUF, conserved in both eukaryotes and prokaryotes. Frataxin (FXN) is a small protein found in humans, plants, yeast and Gram negative bacteria. In eukaryotes, a defect in FXN leads to drastic phenotypes such as mitochondrial iron accumulation, drastic decrease of Fe-S cluster protein activity, sensitivity to oxidants. In humans, FXN deficiency is responsible for the neurodegenerative disease, Friedreich’s ataxia. In prokaryotes like E. coli, a defect in CyaY, the bacterial FXN homolog, does not lead to significant phenotypes compared to the wild-type strain. During my thesis, I investigated the role of the bacterial FXN CyaY in E. coli. I showed that, in vivo, CyaY assisted the ISC-catalyzed Fe-S cluster biogenesis. A genetic link was also observed between cyaY and iscX, demonstrating that these proteins participate in Fe-S cluster biogenesis. In a second part, I investigated the differences between the impact of the eukaryotic versus prokaryotic FXN. I showed that the IscU 108th residue is crucial for the CyaY-dependency. Finally, I used a transcriptomic approach to test whether CyaY has a global role in E. coli

Construction d'un questionnaire d'évaluation des compétences de la personne diabétique

L'éducation thérapeutique permet au patient diabétique de mieux gérer sa maladie en acquérant des compétences dont l'évaluation est un moyen de mesurer l'impact des programmes éducatifs. L'objectif est de construire de compétences, de le tester auprès de patients diabétiques et de l'analyser pour en trouver des pistes d'amélioration. Les objectifs d'acquisition de compétences d'auto-soins et de sécurité sont extraits d'un programme éducatif de diabétologie du CHU de Clermont-Ferrand. Des principes du test de concordance de script sont utilisés. Plusieurs professionnels et patients sont impliqués dans la phase de construction. Le questionnaire est proposé à des personnes diabétiques hospitalisés ou vus en ambulatoire par des pharmaciens et une association de patients. Sont inclus des patients autonomes, ayant un lecteur de glycémie et un traitement pouvant entraîner des hypoglycémies. Les analyses portent sur la faisabilité, l'acceptabilité du questionnaire et la répartition des réponses. Des scores moyens sont établis à partir des réponses des soignants. Le questionnaire comprend 14 questions pour la description de la population, 103 items explorant les compétences de mémorisation et de résolution de problème. Sur 362 questionnaires, 173 ont été retournés et 147 ont été analysés. Les patients ont une ancienneté de la maladie de 20 ans en moyenne, sont vus par un diabétologue pour 79%, et 79% ont un traitement par insuline. Sur 113 items, 91 ont un taux de réponse supérieur à 80%. Sur 94 items, 35 ont un effet de sol ou plafond. Seize soignants ont rempli le questionnaire pour l'établissement des scores. Le taux de retour des questionnaires est satisfaisant. L'acceptabilité est insuffisante pour les questions sur l'hyperglycémie. Les questions suscitant la prise de décisions sur l'hypoglycémie et l'adaptation de traitement sont les plus intéressantes car le taux de réponse est satisfaisant et les réponses sont réparties. Le choix du panel d'expert est discuté. Le questionnaire doit être retravaillé en équipe pluriprofessionnelle. Le questionnaire pourrait être différent en fonction du type de diabète. Les questions mobilisant la réflexion seront privilégiées.CLERMONT FD-BCIU-Santé (631132104) / SudocSudocFranceF

Reprint of: Iron/sulfur proteins biogenesis in prokaryotes: Formation, regulation and diversity

AbstractIron/sulfur centers are key cofactors of proteins intervening in multiple conserved cellular processes, such as gene expression, DNA repair, RNA modification, central metabolism and respiration. Mechanisms allowing Fe/S centers to be assembled, and inserted into polypeptides have attracted much attention in the last decade, both in eukaryotes and prokaryotes. Basic principles and recent advances in our understanding of the prokaryotic Fe/S biogenesis ISC and SUF systems are reviewed in the present communication. Most studies covered stem from investigations in Escherichia coli and Azotobacter vinelandii. Remarkable insights were brought about by complementary structural, spectroscopic, biochemical and genetic studies. Highlights of the recent years include scaffold mediated assembly of Fe/S cluster, A-type carriers mediated delivery of clusters and regulatory control of Fe/S homeostasis via a set of interconnected genetic regulatory circuits. Also, the importance of Fe/S biosynthesis systems in mediating soft metal toxicity was documented. A brief account of the Fe/S biosynthesis systems diversity as present in current databases is given here. Moreover, Fe/S biosynthesis factors have themselves been the object of molecular tailoring during evolution and some examples are discussed here. An effort was made to provide, based on the E. coli system, a general classification associating a given domain with a given function such as to help next search and annotation of genomes. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems

Turning Escherichia coli into a Frataxin-Dependent Organism

Fe-S bound proteins are ubiquitous and contribute to most basic cellular processes. A defect in the ISC components catalyzing Fe-S cluster biogenesis leads to drastic phenotypes in both eukaryotes and prokaryotes. In this context, the Frataxin protein (FXN) stands out as an exception. In eukaryotes, a defect in FXN results in severe defects in Fe-S cluster biogenesis, and in humans, this is associated with Friedreich’s ataxia, a neurodegenerative disease. In contrast, prokaryotes deficient in the FXN homolog CyaY are fully viable, despite the clear involvement of CyaY in ISC-catalyzed Fe-S cluster formation. The molecular basis of the differing importance in the contribution of FXN remains enigmatic. Here, we have demonstrated that a single mutation in the scaffold protein IscU rendered E. coli viability strictly dependent upon a functional CyaY. Remarkably, this mutation changed an Ile residue, conserved in prokaryotes at position 108, into a Met residue, conserved in eukaryotes. We found that in the double mutant IscUIM ΔcyaY, the ISC pathway was completely abolished, becoming equivalent to the ΔiscU deletion strain and recapitulating the drastic phenotype caused by FXN deletion in eukaryotes. Biochemical analyses of the “eukaryotic-like” IscUIM scaffold revealed that it exhibited a reduced capacity to form Fe-S clusters. Finally, bioinformatic studies of prokaryotic IscU proteins allowed us to trace back the source of FXN-dependency as it occurs in present-day eukaryotes. We propose an evolutionary scenario in which the current mitochondrial Isu proteins originated from the IscUIM version present in the ancestor of the Rickettsiae. Subsequent acquisition of SUF, the second Fe-S cluster biogenesis system, in bacteria, was accompanied by diminished contribution of CyaY in prokaryotic Fe-S cluster biogenesis, and increased tolerance to change in the amino acid present at the 108th position of the scaffold

Synthesis of conjugates between oxazolidinone antibiotics and a pyochelin analogue

International audienc

Prevalence of cardiovascular risk factors in a population of French firefighters

Firefighters&apos; activities increase the risk of sudden cardiac events. The main objective of this study was to describe the Loire firefighters&apos; cardiovascular risk factors according to their cardiovascular risk and to their professional status. A retrospective study of the entire population of firefighters of the Loire department was conducted. Risk factors derived from the data collected during the occupational health follow-up medical examinations were described and the cardiovascular risk was assessed for 417 firefighters. The most frequent cardiovascular risk factors were: overweight and obesity (62.1%), high blood pressure (27.8%) and active smoking (16,1%). There were no significant differences between career firefighters and volunteers. The prevalence of risk factors for cardiovascular diseases is less than in the general population. Obesity remains the most common risk factor, especially among firefighters with high cardiovascular risk