Construction of improved temperature-sensitive and mobilizable vectors and their use for constructing mutations in the adhesin-encoding acm gene of poorly transformable clinical Enterococcus faecium strains.

Inactivation by allelic exchange in clinical isolates of the emerging nosocomial pathogen Enterococcus faecium has been hindered by lack of efficient tools, and, in this study, transformation of clinical isolates was found to be particularly problematic. For this reason, a vector for allelic replacement (pTEX5500ts) was constructed that includes (i) the pWV01-based gram-positive repAts replication region, which is known to confer a high degree of temperature intolerance, (ii) Escherichia coli oriR from pUC18, (iii) two extended multiple-cloning sites located upstream and downstream of one of the marker genes for efficient cloning of flanking regions for double-crossover mutagenesis, (iv) transcriptional terminator sites to terminate undesired readthrough, and (v) a synthetic extended promoter region containing the cat gene for allelic exchange and a high-level gentamicin resistance gene, aph(2'')-Id, to distinguish double-crossover recombination, both of which are functional in gram-positive and gram-negative backgrounds. To demonstrate the functionality of this vector, the vector was used to construct an acm (encoding an adhesin to collagen from E. faecium) deletion mutant of a poorly transformable multidrug-resistant E. faecium endocarditis isolate, TX0082. The acm-deleted strain, TX6051 (TX0082Deltaacm), was shown to lack Acm on its surface, which resulted in the abolishment of the collagen adherence phenotype observed in TX0082. A mobilizable derivative (pTEX5501ts) that contains oriT of Tn916 to facilitate conjugative transfer from the transformable E. faecalis strain JH2Sm::Tn916 to E. faecium was also constructed. Using this vector, the acm gene of a nonelectroporable E. faecium wound isolate was successfully interrupted. Thus, pTEX5500ts and its mobilizable derivative demonstrated their roles as important tools by helping to create the first reported allelic replacement in E. faecium; the constructed this acm deletion mutant will be useful for assessing the role of acm in E. faecium pathogenesis using animal models.

Analyzing the function of myogenin in adult satellite cells through the construction of a myogenin conditional allele

Although mechanisms regulating the formation of embryonic skeletal muscle are well characterized, less is known about muscle formation in postnatal life. This disparity is unfortunate because the largest increases in skeletal muscle mass occur after birth. Adult muscle stem cells (satellite cells) appear to recapitulate the events that occur in embryonic myoblasts. In particular, the myogenic basic helix-loop-helix factors, which have crucial functions in embryonic muscle development, are assumed to have similar roles in postnatal muscle formation. Here, I test this assumption by determining the role of the myogenic regulator myogenin in postnatal life. Myogenin-null mice die at birth, necessitating the generation of floxed alleles of myogenin and the use of cre-recombinase lines to delete myogenin. Removing myogenin before embryonic muscle development resulted in myofiber deficiencies identical to those observed in myogenin-null mice. However, mice in which myogenin was deleted following embryonic muscle development had normal skeletal muscle, except for modest alterations in MRF4 and MyoD expression. Notably, myogenin-deleted mice were 30% smaller than controls, suggesting that myogenin's absence disrupted general body growth. These results suggest that skeletal muscle growth in postnatal life is controlled by mechanisms distinct from those occurring in embryonic muscle development. ^

The construction of aging and health in older African American women

Persistence of racial and ethnic health disparities and governmental policies based on outdated ideas of aging call for inclusive approaches to the study of elder African Americans. The lived experiences of aging among urban, poor African American women, who comprise a vulnerable population, are not well known, as most studies focus on mainstream populations. Gerontological studies have tended to employ methods that collapse contextual information for ease of analysis, thus failing to capture nuanced information critically relevant to health of marginalized groups. Few researchers have been successful highlighting the importance of local knowledge, resilience, and resources for health by using participatory methods with older Black women. This study utilizes participatory principles to gather discursive data from nine older African American women, engaged in three generational cohorts: those born around World War II, women born after the great depression, and those born before the great depression. Videotaped and transcribed conversations of cohorts were analyzed in search of contextual factors that influence their experience of aging and health. As women responded to general themes that provoked their talk about their lives, they helped answer the study's questions: How do older African American women make sense of their aging experience? What are some of the important social and cultural influences that shape the construction of aging and health by these women? Are generational discourse groups an effective tool for exploring changes in the experiences of aging? A key finding demonstrated rich heterogeneity of experiences with strong generational influences on the construction of aging and health. The participants' moral orders comprised of traditional values of family, reinforced by personal experiences and the church, have guided their lives through oppression and stress but appear to be failing younger women who have greater exposure to new environmental pressures. Limited time and the size of the study were weaknesses although the women's interest in the study and their participation were gratifying. The participants served to highlight the importance of recognizing generational and other contextual factors in formation of ideas of aging and likelihood of additional challenges to the experience of old age among older, poorer, African Americans. ^

Richard Seaford. Cosmology and the Polis. The social Construction of Space and Time in the Tragedies of Aeschylus, Cambridge University Press, Cambridge, 2012, xiii + 366 pp.

Fil: Fernández Deagustini, María del Pilar. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación. Instituto de Investigaciones en Humanidades y Ciencias Sociales (UNLP-CONICET); Argentina.

The Construction of the Image of Peace in Ancient Greece : A few literary and Iconographic Evidences

El presente artículo busca identificar y analizar algunas de los principales tratamientos poéticos y artísticos del binomio paz / riqueza en una perspectiva diacrónica y comparativa, intentando aislar las más frecuentes imágenes, metáforas y epítetos relacionados con ese tema. El estudio de los pasajes elegidos deja claro cómo ambos, poetas y artistas plásticos, conocían y manipulaban con su arte un mismo patrimonio bastante antiguo

Richard Seaford. Cosmology and the Polis. The social Construction of Space and Time in the Tragedies of Aeschylus, Cambridge University Press, Cambridge, 2012, xiii + 366 pp.

Fil: Fernández Deagustini, María del Pilar. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación. Instituto de Investigaciones en Humanidades y Ciencias Sociales (UNLP-CONICET); Argentina.

The Construction of the Image of Peace in Ancient Greece : A few literary and Iconographic Evidences

El presente artículo busca identificar y analizar algunas de los principales tratamientos poéticos y artísticos del binomio paz / riqueza en una perspectiva diacrónica y comparativa, intentando aislar las más frecuentes imágenes, metáforas y epítetos relacionados con ese tema. El estudio de los pasajes elegidos deja claro cómo ambos, poetas y artistas plásticos, conocían y manipulaban con su arte un mismo patrimonio bastante antiguo

The Construction of the Image of Peace in Ancient Greece : A few literary and Iconographic Evidences

El presente artículo busca identificar y analizar algunas de los principales tratamientos poéticos y artísticos del binomio paz / riqueza en una perspectiva diacrónica y comparativa, intentando aislar las más frecuentes imágenes, metáforas y epítetos relacionados con ese tema. El estudio de los pasajes elegidos deja claro cómo ambos, poetas y artistas plásticos, conocían y manipulaban con su arte un mismo patrimonio bastante antiguo