RESUMEN
The Origin Recognition Complex (ORC) is essential for replication, heterochromatin formation, telomere maintenance and genome stability in eukaryotes. Here we present the structure of the yeast Orc1 BAH domain bound to the nucleosome core particle. Our data reveal that Orc1, unlike its close homolog Sir3 involved in gene silencing, does not appear to discriminate between acetylated and non-acetylated lysine 16, modification states of the histone H4 tail that specify open and closed chromatin respectively. We elucidate the mechanism for this unique feature of Orc1 and hypothesize that its ability to interact with nucleosomes regardless of K16 modification state enables it to perform critical functions in both hetero- and euchromatin. We also show that direct interactions with nucleosomes are essential for Orc1 to maintain the integrity of rDNA borders during meiosis, a process distinct and independent from its known roles in silencing and replication.
Asunto(s)
Nucleosomas/metabolismo , Complejo de Reconocimiento del Origen/química , Complejo de Reconocimiento del Origen/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Ciclo Celular , Ensamble y Desensamble de Cromatina , Eucromatina/genética , Eucromatina/metabolismo , Heterocromatina/genética , Heterocromatina/metabolismo , Histonas/genética , Histonas/metabolismo , Nucleosomas/genética , Complejo de Reconocimiento del Origen/genética , Unión Proteica , Dominios Proteicos , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas Reguladoras de Información Silente de Saccharomyces cerevisiae/genética , Proteínas Reguladoras de Información Silente de Saccharomyces cerevisiae/metabolismoRESUMEN
In order to propose alternative treatments for strabismus, conventional visual therapies implemented in VR, which could be rendered in portable devices for pediatric strabismus treatment is proposed in this paper. In comparison with other virtual environments for visual correction proposes, the proposed system is based on conventional visual therapies for amblyopia and strabismus treatment. Three fundamental visual therapeutic exercises were considered in the present proposal: (1) Brock cord, (2) approach technique, and (3) convergence and divergence. The first exercise, Brock Cord, has the purpose of improving the binocular fixation for exotropia and esotropia. The second exercise pursues to normalize the Cerebral Perfusion Pressure by an approach technique. The third exercise known as fusion of eccentric circles, aims vision training by converging and diverging objects at specific distances. Before a clinical application, it was paramount important to guarantee system simplicity and versatility for both clinicians and infant patients. Therefore, the user experience evaluation of a sample of 45 students between 17 and 28 years old was undertaken. The system proposed in this paper achieved a pragmatic quality above average (1.73), a parameter that reflects simplicity and versatility. In addition, the present VR system displayed attractiveness (2.03) and hedonic (1.90) qualities above average. Then, it is expected that end-users will follow the visual exercise program.
Asunto(s)
Ambliopía/terapia , Esotropía/terapia , Exotropía/terapia , Estrabismo/terapia , Realidad Virtual , Adolescente , Adulto , Humanos , Visión Binocular , Adulto JovenRESUMEN
El empiema subdural es una complicación rara de las infecciones por Salmonela. Se informa de un lactante con desnutrición grave y síndrome de Down, quien cursó con gastroenteritis aguda y bacteremia por Salmonella anteritidis que después de ser tratado con antibióticos fue dado de alta con aparente mejoría clínica. Un mes después desarrolló un síndrome febril y dificultad respiratoria, mostrando la fontanela anterior abombada; se agregaron crisis convulsivas focalizadas y deterioro cefalocaudal. El estudio microbiológico informó la presencia de bacilos gram negativos y se cultivó Salmonela enteritidis, sensible a cefotaxima. Fue tratado durante tres semanas con antibióticos para luego ser dado de alta