Regulation of surface architecture by symbiotic bacteria mediates host colonization

Microbes occupy countless ecological niches in nature. Sometimes these environments may be on or within another organism, as is the case in both microbial infections and symbiosis of mammals. Unlike pathogens that establish opportunistic infections, hundreds of human commensal bacterial species establish a lifelong cohabitation with their hosts. Although many virulence factors of infectious bacteria have been described, the molecular mechanisms used during beneficial host–symbiont colonization remain almost entirely unknown. The novel identification of multiple surface polysaccharides in the important human symbiont Bacteroides fragilis raised the critical question of how these molecules contribute to commensalism. To understand the function of the bacterial capsule during symbiotic colonization of mammals, we generated B. fragilis strains deleted in the global regulator of polysaccharide expression and isolated mutants with defects in capsule expression. Surprisingly, attempts to completely eliminate capsule production are not tolerated by the microorganism, which displays growth deficits and subsequent reversion to express capsular polysaccharides. We identify an alternative pathway by which B. fragilis is able to reestablish capsule production and modulate expression of surface structures. Most importantly, mutants expressing single, defined surface polysaccharides are defective for intestinal colonization compared with bacteria expressing a complete polysaccharide repertoire. Restoring the expression of multiple capsular polysaccharides rescues the inability of mutants to compete for commensalism. These findings suggest a model whereby display of multiple capsular polysaccharides provides essential functions for bacterial colonization during host–symbiont mutualism

Autoagregación de apolipoproteína A-I humana : Estudios con mutantes de cisteína marcadas con pirenil-maleimida

La apolipoproteína A-I (apoAI) es la proteína mayoritaria de las lipoproteínas de alta densidad (HDL) a las que se les atribuye un rol antiaterogénico, en especial por su participación en el transporte del exceso de colesterol desde tejidos periféricos hacia el hígado para su catabolismo y eliminación. ApoAI está constituida por hélices anfipáticas que en agua forman un ramillete de estructura terciaria poco definida o glóbulo fundido; y que en función de la concentración se autoagrega para formar dímeros y oligómeros de diferente tamaño. Objetivos: obtener información sobre la autoagregación en solución e interacción con membrana de ApoA-I ya que es importante para comprender los mecanismos de generación de HDL, así como también la amiloideogénesis.Facultad de Ciencias Médica

Autoagregación de apolipoproteína A-I humana : Estudios con mutantes de cisteína marcadas con pirenil-maleimida

La apolipoproteína A-I (apoAI) es la proteína mayoritaria de las lipoproteínas de alta densidad (HDL) a las que se les atribuye un rol antiaterogénico, en especial por su participación en el transporte del exceso de colesterol desde tejidos periféricos hacia el hígado para su catabolismo y eliminación. ApoAI está constituida por a-hélices anfipáticas que en agua forman un ramillete de estructura terciaria poco definida o glóbulo fundido; y que en función de la concentración se autoagrega para formar dímeros y oligómeros de diferente tamaño.Facultad de Ciencias Médica

Autoagregación de apolipoproteína A-I humana : Estudios con mutantes de cisteína marcadas con pirenil-maleimida

La apolipoproteína A-I (apoAI) es la proteína mayoritaria de las lipoproteínas de alta densidad (HDL) a las que se les atribuye un rol antiaterogénico, en especial por su participación en el transporte del exceso de colesterol desde tejidos periféricos hacia el hígado para su catabolismo y eliminación. ApoAI está constituida por a-hélices anfipáticas que en agua forman un ramillete de estructura terciaria poco definida o glóbulo fundido; y que en función de la concentración se autoagrega para formar dímeros y oligómeros de diferente tamaño.Facultad de Ciencias Médica

Autoagregación de apolipoproteína A-I humana : Estudios con mutantes de cisteína marcadas con pirenil-maleimida

La apolipoproteína A-I (apoAI) es la proteína mayoritaria de las lipoproteínas de alta densidad (HDL) a las que se les atribuye un rol antiaterogénico, en especial por su participación en el transporte del exceso de colesterol desde tejidos periféricos hacia el hígado para su catabolismo y eliminación. ApoAI está constituida por a-hélices anfipáticas que en agua forman un ramillete de estructura terciaria poco definida o glóbulo fundido; y que en función de la concentración se autoagrega para formar dímeros y oligómeros de diferente tamaño.Facultad de Ciencias Médica

The visible human slice Web server: a first assessment

The visible human slice server started offering its slicing services at the end of June 1998. From that date until the end of May, more than 280000 slices were extracted from the Visible Man, by laymen interested in anatomy, by students and by specialists. The Slice Server is based one Bi-Pentium PC and 16 disks. It is a scaled down version of a powerful parallel server comprising 5 Bi-Pentium Pro PCs and 60 disks. The parallel server program was created thanks to a computer-aided parallelization framework, which takes over the task of creating a multithreaded pipelined parallel program from a high-level parallel program description. On the full blown architecture, the parallel program enables the extraction and resampling of up to 5 color slices per second. Extracting 5 slice/s requires to access the disks and extract subvolumes of the Visible Human at an aggregate throughput of 105 MB/s. The publicly accessible server enables to extract slices having any orientation. The slice position and orientation can either be specified for each slice separately or as a position and orientation offered by a Java applet and possible future improvements. In the very near future, the Web Slice Server will offer additional services, such as the possibility to extract ruled surfaces and to extract animations incorporating slices perpendicular to a user defined trajector

Genes relacionados a procesos inflamatorios en macrófagos humanos THP1

El objetivo fue estudiar la expresión de genes implicados en el proceso inflamatorio y en el metabolismo de glucocorticoides en macrófagos expuestos a LDL oxidadas (LDL-Ox). Fracciones de LDL fueron aisladas a partir de plasma humano y luego peroxidadas in vitro con Cu++.Facultad de Ciencias Médica

Genes relacionados a procesos inflamatorios en macrófagos humanos THP1

El objetivo fue estudiar la expresión de genes implicados en el proceso inflamatorio y en el metabolismo de glucocorticoides en macrófagos expuestos a LDL oxidadas (LDL-Ox). Fracciones de LDL fueron aisladas a partir de plasma humano y luego peroxidadas in vitro con Cu++.Facultad de Ciencias Médica

Cognitive and memory training in adults at risk of dementia: A Systematic Review

<p>Abstract</p> <p>Background</p> <p>Effective non-pharmacological cognitive interventions to prevent Alzheimer's dementia or slow its progression are an urgent international priority. The aim of this review was to evaluate cognitive training trials in individuals with mild cognitive impairment (MCI), and evaluate the efficacy of training in memory strategies or cognitive exercises to determine if cognitive training could benefit individuals at risk of developing dementia.</p> <p>Methods</p> <p>A systematic review of eligible trials was undertaken, followed by effect size analysis. Cognitive training was differentiated from other cognitive interventions not meeting generally accepted definitions, and included both cognitive exercises and memory strategies.</p> <p>Results</p> <p>Ten studies enrolling a total of 305 subjects met criteria for cognitive training in MCI. Only five of the studies were randomized controlled trials. Meta-analysis was not considered appropriate due to the heterogeneity of interventions. Moderate effects on memory outcomes were identified in seven trials. Cognitive exercises (relative effect sizes ranged from .10 to 1.21) may lead to greater benefits than memory strategies (.88 to -1.18) on memory.</p> <p>Conclusions</p> <p>Previous conclusions of a lack of efficacy for cognitive training in MCI may have been influenced by not clearly defining the intervention. Our systematic review found that cognitive exercises can produce moderate-to-large beneficial effects on memory-related outcomes. However, the number of high quality RCTs remains low, and so further trials must be a priority. Several suggestions for the better design of cognitive training trials are provided.</p

The European Nucleotide Archive

The European Nucleotide Archive (ENA; http://www.ebi.ac.uk/ena) is Europe’s primary nucleotide-sequence repository. The ENA consists of three main databases: the Sequence Read Archive (SRA), the Trace Archive and EMBL-Bank. The objective of ENA is to support and promote the use of nucleotide sequencing as an experimental research platform by providing data submission, archive, search and download services. In this article, we outline these services and describe major changes and improvements introduced during 2010. These include extended EMBL-Bank and SRA-data submission services, extended ENA Browser functionality, support for submitting data to the European Genome-phenome Archive (EGA) through SRA, and the launch of a new sequence similarity search service