Tolerance to stress and environmental adaptability of Chromobacterium violaceum

Chromobacterium violaceum is a Gram-negative bacterium, abundant in a variety of ecosystems in tropical and subtropical regions, including the water and borders of the Negro River, a major component of the Amazon Basin. As a free-living microorganism, C. violaceum is exposed to a series of variable conditions, such as different sources and abundance of nutrients, changes in temperature and pH, toxic compounds and UV rays. These variations, and the wide range of environments, require great adaptability and strong protective systems. The complete genome sequencing of this bacterium has revealed an enormous number and variety of ORFs associated with alternative pathways for energy generation, transport-related proteins, signal transduction, cell motility, secretion, and secondary metabolism. Additionally, the limited availability of iron in most environments can be overcome by iron-chelating compounds, iron-storage proteins, and by several proteins related to iron metabolism in the C. violaceum genome. Osmotically inducible proteins, transmembrane water-channel, and other membrane porins may be regulating the movement of water and maintaining the cell turgor, activities which play an important role in the adaptation to variations in osmotic pressure. Several proteins related to tolerance against antimicrobial compounds, heavy metals, temperature, acid and UV light stresses, others that promote survival under starvation conditions, and enzymes capable of detoxifying reactive oxygen species were also detected in C. violaceum. All these features together help explain its remarkable competitiveness and ability to survive under different types of environmental stress

Trastornos del dormir en una población de preadolescentes sanos / Sleep disturbances in healthy pre-adolescents population

Se realizó un estudio transversal, observacional indirecto para establecer o determinar la prevalencia de los trastornos del dormir en 500 preadolescentes sanos del Barrio "Simon Bolivar" de la ciudad de Santo Domingo. La incidencia en los trastornos del dormir en la población en estudio es de un 51.8 por ciento para las edades comprendidas entre 8-9 años y de 47.9 por ciento en el grupo de 9-10 años. Se concluye confirmando lo indicado por otros estudios, que el índice de trastornos del dormir en la población estudiada supuestamente sana se debe a situaciones conflictivas psicológicas y precariedades económicas en las que está inmersa la familia