In ovo time-lapse analysis after dorsal neural tube ablation shows rerouting of chick hindbrain neural crest

Previous analyses of single neural crest cell trajectories have suggested important roles for interactions between neural crest cells and the environment, and amongst neural crest cells. To test the relative contribution of intrinsic versus extrinsic information in guiding cells to their appropriate sites, we ablated subpopulations of premigratory chick hindbrain neural crest and followed the remaining neural crest cells over time using a new in ovo imaging technique. Neural crest cell migratory behaviors are dramatically different in ablated compared with unoperated embryos. Deviations from normal migration appear either shortly after cells emerge from the neural tube or en route to the branchial arches, areas where cell-cell interactions typically occur between neural crest cells in normal embryos. Unlike the persistent, directed trajectories in normal embryos, neural crest cells frequently change direction and move somewhat chaotically after ablation. In addition, the migration of neural crest cells in collective chains, commonly observed in normal embryos, was severely disrupted. Hindbrain neural crest cells have the capacity to reroute their migratory pathways and thus compensate for missing neural crest cells after ablation of neighboring populations. Because the alterations in neural crest cell migration are most dramatic in regions that would normally foster cell-cell interactions, the trajectories reported here argue that cell-cell interactions have a key role in the shaping of the neural crest migration

Government Performance and Life Satisfaction in Contemporary Britain

This paper investigates relationships between public policy outcomes and life satisfaction in contemporary Britain. Monthly national surveys gathered between April 2004 and December 2008 are used to analyze the impact of policy delivery both at the micro and macro levels, the former relating to citizens personal experiences, and the latter to cognitive evaluations of and affective reactions to the effectiveness of policies across the country as a whole. The impact of salient political events and changes in economic context involving the onset of a major financial crisis also are considered. Analyses reveal that policy outcomes, especially microlevel ones, significantly influence life satisfaction. The effects of both micro- and macrolevel outcomes involve both affective reactions to policy delivery and cognitive judgments about government performance. Controlling for these and other factors, the broader economic context in which policy judgments are made also influences life satisfaction. © 2010 Southern Political Science Association

Ancient Pbx-Hox signatures define hundreds of vertebrate developmental enhancers

Background: Gene regulation through cis-regulatory elements plays a crucial role in development and disease. A major aim of the post-genomic era is to be able to read the function of cis-regulatory elements through scrutiny of their DNA sequence. Whilst comparative genomics approaches have identified thousands of putative regulatory elements, our knowledge of their mechanism of action is poor and very little progress has been made in systematically de-coding them. Results: Here, we identify ancient functional signatures within vertebrate conserved non-coding elements (CNEs) through a combination of phylogenetic footprinting and functional assay, using genomic sequence from the sea lamprey as a reference. We uncover a striking enrichment within vertebrate CNEs for conserved binding-site motifs of the Pbx-Hox hetero-dimer. We further show that these predict reporter gene expression in a segment specific manner in the hindbrain and pharyngeal arches during zebrafish development. Conclusions: These findings evoke an evolutionary scenario in which many CNEs evolved early in the vertebrate lineage to co-ordinate Hox-dependent gene-regulatory interactions that pattern the vertebrate head. In a broader context, our evolutionary analyses reveal that CNEs are composed of tightly linked transcription-factor binding-sites (TFBSs), which can be systematically identified through phylogenetic footprinting approaches. By placing a large number of ancient vertebrate CNEs into a developmental context, our findings promise to have a significant impact on efforts toward de-coding gene-regulatory elements that underlie vertebrate development, and will facilitate building general models of regulatory element evolution

Vulnerable Americans rally around a president in a crisis. but polarization means this hasn’t happened during the Covid-19 pandemic.

Historically in times of crisis, presidents experience a polling boost as Americans ‘rally around the flag’, but this has not been the case during President Trump’s handling of the COVID-19 pandemic. In new analysis, Harold Clarke, Marianne Stewart and Paul Whiteley find that the massive partisan and ideological differences in the electorate meant that the expected spike in Trump’s support did not occur – especially among the most vulnerable, who would ordinarily be more likely to rally around the president

Given its likely adverse political effects, the problem of social care funding is unlikely to be solved any time soon

Paul Whiteley, Harold Clarke, and Marianne Stewart write that a large increase in funding for social care would mean a significant hike in taxation, largely paid for by the young and the middle-aged with the elderly being the beneficiaries. This would create political problems for all parties

Role of Mucosal Inflammation in Eosinophilic Esophagitis: Review of the Literature

Eosinophilic esophagitis (EE) is increasingly recognized in adults. It is an inflammatory disease of the esophageal mucosa, with variable presentation, unresponsive to acid suppression therapy. The diagnosis requires histological confirmation of intense eosinophilic infiltration on esophageal biopsy specimen, however exact criteria required to make a diagnosis of EE is still being debated and a clear differentiation from gastroesophageal reflux disease (GERD) is important. Allergen elimination or anti-inflammatory therapy may be effective in such patients. The imperfect diagnostic criteria for EE mandate an understanding of the immunology and the pathophysiology of the disease. It may facilitate the introduction of novel treatment modalities in an individual unresponsive to acid suppression therapy. This paper describes basic elements of the immune-mediated injury to the esophageal mucosa and management aspects to provide a better understanding of the condition