The Chlamydia psittaci Genome: A Comparative Analysis of Intracellular Pathogens

Chlamydiaceae are a family of obligate intracellular pathogens causing a wide range of diseases in animals and humans, and facing unique evolutionary constraints not encountered by free-living prokaryotes. To investigate genomic aspects of infection, virulence and host preference we have sequenced Chlamydia psittaci, the pathogenic agent of ornithosis.A comparison of the genome of the avian Chlamydia psittaci isolate 6BC with the genomes of other chlamydial species, C. trachomatis, C. muridarum, C. pneumoniae, C. abortus, C. felis and C. caviae, revealed a high level of sequence conservation and synteny across taxa, with the major exception of the human pathogen C. trachomatis. Important differences manifest in the polymorphic membrane protein family specific for the Chlamydiae and in the highly variable chlamydial plasticity zone. We identified a number of psittaci-specific polymorphic membrane proteins of the G family that may be related to differences in host-range and/or virulence as compared to closely related Chlamydiaceae. We calculated non-synonymous to synonymous substitution rate ratios for pairs of orthologous genes to identify putative targets of adaptive evolution and predicted type III secreted effector proteins.This study is the first detailed analysis of the Chlamydia psittaci genome sequence. It provides insights in the genome architecture of C. psittaci and proposes a number of novel candidate genes mostly of yet unknown function that may be important for pathogen-host interactions

Public Transit Accessibility: Blind Passengers Speak Out

Riding public transit can be confusing for everyone, especially in an unfamiliar environment. One needs to figure out which transportation lines to take to reach a destination, when and where to catch a bus or a train, when to exit, and how to negotiate transfers. For those with sensorial or cognitive disa- bilities, these problems become even more daunting. Several technological ap- proaches have been proposed to facilitate use of public transit for everyone. For any assistive technology to be successful, though, it is imperative that it is de- veloped from the ground up with a clear understanding of the intended users’ needs and requirements, and possibly with a direct participation of these users throughout the project lifecycle. In this study, we conduct a focus group with blind participants, designed to highlight the main issues, problems, and limitations with the current transit system in our local area as well as the perception of the participants our proposed RouteMe2 technology. We found two core categories of issues faced by blind travelers: (1) spatial/location awareness, and (2) temporal/ time awareness. Configurability and accessibility were the most desired features requested for a new transit information app

“Contextualizing Context”: Reconciling Environmental Exposures, Social Networks, and Location Preferences in Health Research

International audiencePurpose of review: The aim of this paper is to review the recent advances in health and place research and discuss concepts useful to explore how context affects health. More specifically, it reviews measures and tools used to account for place; concepts relating to daily mobility and multiple exposure to places, and further points to the intertwining between social and spatial networks to help further our understanding of how context translates into health profiles.Recent findings: Significant advances in environmental or neighborhood effects have been made in the last decades. Specifically, conceptual and methodological developments have improved our consideration of spatial processes, shifting from a residential-based view of context to a more dynamic activity space and daily mobility paradigm. Yet, such advances have led to overlooking other potentially important aspects related to social networks and decision-making processes. With an increasing capacity to collect high-precision data on daily mobility and behavior, new possibilities in understanding how environments relate to behavior and health inequalities arise. Two overlooked aspects need to be addressed: the questions of "with or for whom", and "why". While the former calls for a better consideration of social networks and social interactions, the latter calls for refining our understanding of place preference and decision-making leading to daily mobility and multiple exposures