Pratique de l'hétérogénéité en peinture : Les contiguïtés de la représentation

Cette recherche s'inscrit dans la continuité d'une pratique établie de l'hétérogénéité en peinture. Elle réinvente, renouvelle, mais surtout met en examen une attitude créatrice, au même titre que les procédés et les stratégies déterminant mon parcours de production. Ainsi, un classement iconographique issu de la constitution d'une banque d'images pervertira ma démarche et ses mobiles initiaux. Au reste, mon usage de disparité de signes picturaux se circonscrira dans une dislocation des mécanismes de la représentation. Ces préoccupations participeront à l'édification d'une grille d'analyse spécifique appliquée sur le corpus résultant. Je procède là à une discrimination des opérations de restitution et de désignation selon une taxonomie personnelle inventoriant divers modes d'interventions picturales

Polymorphisms in Brucella Carbonic Anhydrase II Mediate CO 2 Dependence and Fitness in vivo

Some Brucella isolates are known to require an increased concentration of CO2 for growth, especially in the case of primary cultures obtained directly from infected animals. Moreover, the different Brucella species and biovars show a characteristic pattern of CO2 requirement, and this trait has been included among the routine typing tests used for species and biovar differentiation. By comparing the differences in gene content among different CO2-dependent and CO2-independent Brucella strains, we have confirmed that carbonic anhydrase (CA) II is the enzyme responsible for this phenotype in all the Brucella strains tested. Brucella species contain two CAs of the ? family, CA I and CA II; genetic polymorphisms exist for both of them in different isolates, but only those putatively affecting the activity of CA II correlate with the CO2 requirement of the corresponding isolate. Analysis of these polymorphisms does not allow the determination of CA I functionality, while the polymorphisms in CA II consist of small deletions that cause a frameshift that changes the C-terminus of the protein, probably affecting its dimerization status, essential for the activity. CO2-independent mutants arise easily in vitro, although with a low frequency ranging from 10-6 to 10-10 depending on the strain. These mutants carry compensatory mutations that produce a full-length CA II. At the same time, no change was observed in the sequence coding for CA I. A competitive index assay designed to evaluate the fitness of a CO2-dependent strain compared to its corresponding CO2-independent strain revealed that while there is no significant difference when the bacteria are grown in culture plates, growth in vivo in a mouse model of infection provides a significant advantage to the CO2-dependent strain. This could explain why some Brucella isolates are CO2 dependent in primary isolation. The polymorphism described here also allows the in silico determination of the CO2 requirement status of any Brucella strain.FUNDING: This work was supported by grants BFU2011-25658 from the Spanish Ministry of Science and Innovation, and by grant 55.JU07.64661 from the University of Cantabria to FS. BA-R was supported by a Scholarship received from DGAPAUNAM PASPA program. The authors want to acknowledge help from María J. Lucas and Elena Cabezón in the drawing and interpretation of crystallographic data

G1-arrested newborn cells are the predominant infectious form of the pathogen Brucella abortus

Several intracellular pathogens, such as Brucella abortus, display a biphasic infection process starting with a non-proliferative stage of unclear nature. Here, we study the cell cycle of B. abortus at the single-cell level, in culture and during infection of HeLa cells and macrophages. The localization of segregation and replication loci of the two bacterial chromosomes indicates that, immediately after being engulfed by host-cell endocytic vacuoles, most bacterial cells are newborn. These bacterial cells do not initiate DNA replication for the next 4 to 6 h, indicating a G1 arrest. Moreover, growth is completely stopped during that time, reflecting a global cell cycle block. Growth and DNA replication resume later, although bacteria still reside within endosomal-like compartments. We hypothesize that the predominance of G1-arrested bacteria in the infectious population, and the bacterial cell cycle arrest following internalization, may constitute a widespread strategy among intracellular pathogens to colonize new proliferation niches

Selection of a mineralocorticoid receptor antagonist for patients with hypertension or heart failure

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102661/1/ejhf31.pd

LE PRATICIEN DEVANT LE CHOIX D'UN ANTITUSSIF

SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

À propos de certaines interactions médicamenteuses fatales

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Les hormones de jouvence

SCOPUS: re.jinfo:eu-repo/semantics/publishe

Les médicaments-vedettes en 1995: succès, échecs et incertitudes

SCOPUS: re.jinfo:eu-repo/semantics/publishe