Global transcriptome analysis of the heat shock response of Bifidobacterium longum

Bifidobacteria are natural inhabitants of the human gastrointestinal tract and have been widely used as functional foods in different products. During industrial processing, bacterial cells undergo several stresses that can limit large-scale production and stability of the final product. To better understand the stress-response mechanisms of bifidobacteria, microarrays were used to obtain a global transcriptome profile of Bifidobacterium longum NCC2705 exposed to a heat shock treatment at 50°C for 3, 7 and 12 min. Gene expression data highlighted a profound modification of gene expression, with 46% of the genes being altered. This analysis revealed a slow-down of Bi. longum general metabolic activity during stress with a simultaneous activation of the classical heat shock stimulon. Moreover, the expression of several genes with unknown function was highly induced under stress conditions. Three of these were conserved in other bacteria species where they were also previously shown to be induced by high temperature, suggesting their widespread role in the heat stress response. Finally, the implication of the trans-translation machinery in the response of Bi. longum cells to heat shock was suggested by the induction of the gene encoding the tmRNA-associated small protein B (SmpB) with concomitant high constitutive expression of the tmRNA gen

Biomarkers of human gastrointestinal tract regions

Dysregulation of intestinal epithelial cell performance is associated with an array of pathologies whose onset mechanisms are incompletely understood. While whole-genomics approaches have been valuable for studying the molecular basis of several intestinal diseases, a thorough analysis of gene expression along the healthy gastrointestinal tract is still lacking. The aim of this study was to map gene expression in gastrointestinal regions of healthy human adults and to implement a procedure for microarray data analysis that would allow its use as a reference when screening for pathological deviations. We analyzed the gene expression signature of antrum, duodenum, jejunum, ileum, and transverse colon biopsies using a biostatistical method based on a multivariate and univariate approach to identify region-selective genes. One hundred sixty-six genes were found responsible for distinguishing the five regions considered. Nineteen had never been described in the GI tract, including a semaphorin probably implicated in pathogen invasion and six novel genes. Moreover, by crossing these genes with those retrieved from an existing data set of gene expression in the intestine of ulcerative colitis and Crohn's disease patients, we identified genes that might be biomarkers of Crohn's and/or ulcerative colitis in ileum and/or colon. These include CLCA4 and SLC26A2, both implicated in ion transport. This study furnishes the first map of gene expression along the healthy human gastrointestinal tract. Furthermore, the approach implemented here, and validated by retrieving known gene profiles, allowed the identification of promising new leads in both healthy and disease state

PERCEPTION ET INTERPRETATION DE SECTIONS ET BLOCS SISMIQUES (OCULOMETRIE ET ANALYSE D'IMAGES)

DANS LE DOMAINE DE L'INTERPRETATION DES IMAGES SISMIQUES A DES FINS DE RECHERCHE DE GISEMENTS D'HYDROCARBURES, LE GEOLOGUE SE TROUVE CONFRONTE A DEUX PROBLEMES MAJEURS : 1. LA TAILLE ET LA COMPLEXITE DES IMAGES SISMIQUES. 2. DES DELAIS D'INTERPRETATION DE PLUS EN PLUS COURTS. LE BUT DE CE TRAVAIL EST DE PROPOSER DES METHODES ET DES ALGORITHMES D'ANALYSE ET DE TRAITEMENT D'IMAGES POUR L'AIDE A L'INTERPRETATION SISMIQUE AFIN D'OFFRIR AUX GEOLOGUES UNE AIDE AUTOMATISEE A L'INTERPRETATION SISMIQUE DANS LE BUT PLUS LOINTAIN DE CONSTRUIRE UN SYSTEME EXPERT DE DIAGNOSTIC. CETTE AIDE NOUS LA VOULONS FIDELE AU SAVOIR-FAIRE DES GEOLOGUES OR CE SAVOIR-FAIRE EST LE FRUIT DE CONNAISSANCES PEU CONNUES. NOUS SUPPORTONS LA THESE QUE LA STRATEGIE OCULAIRE DES GEOLOGUES PENDANT L'INTERPRETATION DES IMAGES SISMIQUES EST UN MOYEN OBJECTIVE POUR DETERMINER COMMENT LES GEOLOGUES INTERPRETENT LES IMAGES SISMIQUES. EN EFFET LE REGARD DES GEOLOGUES SE FIXE PRINCIPALEMENT SUR LES ZONES PORTEUSES D'INFORMATIONS. LE BUT DEVIENT ALORS L'ETUDE DU COMPORTEMENT VISUEL DES GEOLOGUES, LA MISE EN VALEUR DES ZONES D'INSERTS DANS L'IMAGE SISMIQUE ET ENFIN LA CARACTERISATION DES ZONES D'INTERET AU MOYEN D'ATTRIBUTS IMAGES. NOTRE TRAVAIL S'ARTICULE AUTOUR DE 3 AXES : LA PERCEPTION VISUELLE, L'INTERPRETATION SISMIQUE ET ENFIN LE TRAITEMENT D'IMAGES. DANS UN PREMIER CHAPITRE, NOUS PROPOSONS UNE REVUE DES QUESTIONS SUR LA PERCEPTION VISUELLE. ENSUITE NOUS ABORDONS UNE DESCRIPTION DES CARACTERISTIQUES DES IMAGES SISMIQUES ET NOUS RAPPELONS LA DEMARCHE D'INTERPRETATION SISMIQUE DANS UN CONTEXTE DE LA PROSPECTION PETROLIERE. LE 3EME CHAPITRE EST CONSACRE A LA MISE EN UVRE D'UN PROTOCOLE POUR L'ETUDE DU COMPORTEMENT VISUEL FACE A DES IMAGES SISMIQUES STATIQUES ET DYNAMIQUES. DANS LE 4EME CHAPITRE DEUX ATTRIBUTS SISMIQUES SONT PROPOSES POUR LE CODAGE DES DONNEES OCULAIRE ET DANS LE DERNIER CHAPITRE NOUS PRESENTONS LES DIFFERENTS RESULTATS EXPERIMENTAUX AINSI QUE L'EBAUCHE D'UN MODELE D'EXPLORATION AUTOMATIQUE.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Global transcriptome analysis of the heat shock response of Bifidobacterium longum

ISSN:0378-1097ISSN:1574-6968ISSN:0168-6496ISSN:0920-8534ISSN:0168-644

Mining Pits Optimization

The problem comes from mining industry. It consists in optimisation of what is called open pits. The domain or the area where the mine is located, is divided into cubes. For each cube the geologists and the geomechanics engineers give the following information: ffl The percentage of mineral in the cube. ffl The cost of extracting and processing the cube. ffl The safety restrictions for a safe pit at that point. As safety restriction a maximal allowable angle of the walls of the pit is given. Now it is asked for the final shape of the pit, which gives the maximum profit and respects the safety constraints. In the report, the simplification of the problem to 2D is formulated as nonlinear continous and linear binary optimization problem. However, standard optimization packages take too much time in solving large problems, therefore a constructive algorithm is developed for the special case of a constant angle of 45 ffi , which is able to find sub-optimal solutions and needs much less..