The predictive mirror: interactions of mirror and affordance processes during action observation

An important question for the study of social interactions is how the motor actions of others are represented. Research has demonstrated that simply watching someone perform an action activates a similar motor representation in oneself. Key issues include (1) the automaticity of such processes, and (2) the role object affordances play in establishing motor representations of others’ actions. Participants were asked to move a lever to the left or right to respond to the grip width of a hand moving across a workspace. Stimulus-response compatibility effects were modulated by two task-irrelevant aspects of the visual stimulus: the observed reach direction and the match between hand-grasp and the affordance evoked by an incidentally presented visual object. These findings demonstrate that the observation of another person’s actions automatically evokes sophisticated motor representations that reflect the relationship between actions and objects even when an action is not directed towards an object

The First Sequenced Carnivore Genome Shows Complex Host-Endogenous Retrovirus Relationships

Host-retrovirus interactions influence the genomic landscape and have contributed substantially to mammalian genome evolution. To gain further insights, we analyzed a female boxer (Canis familiaris) genome for complexity and integration pattern of canine endogenous retroviruses (CfERV). Intriguingly, the first such in-depth analysis of a carnivore species identified 407 CfERV proviruses that represent only 0.15% of the dog genome. In comparison, the same detection criteria identified about six times more HERV proviruses in the human genome that has been estimated to contain a total of 8% retroviral DNA including solitary LTRs. These observed differences in man and dog are likely due to different mechanisms to purge, restrict and protect their genomes against retroviruses. A novel group of gammaretrovirus-like CfERV with high similarity to HERV-Fc1 was found to have potential for active retrotransposition and possibly lateral transmissions between dog and human as a result of close interactions during at least 10.000 years. The CfERV integration landscape showed a non-uniform intra- and inter-chromosomal distribution. Like in other species, different densities of ERVs were observed. Some chromosomal regions were essentially devoid of CfERVs whereas other regions had large numbers of integrations in agreement with distinct selective pressures at different loci. Most CfERVs were integrated in antisense orientation within 100 kb from annotated protein-coding genes. This integration pattern provides evidence for selection against CfERVs in sense orientation relative to chromosomal genes. In conclusion, this ERV analysis of the first carnivorous species supports the notion that different mammals interact distinctively with endogenous retroviruses and suggests that retroviral lateral transmissions between dog and human may have occurred

Transglutaminase 2-Specific Autoantibodies in Celiac Disease Target Clustered, N-Terminal Epitopes Not Displayed on the Surface of Cells

The gluten-sensitive enteropathy celiac disease is tightly associated with the production of autoantibodies specific for the enzyme transglutaminase 2 (TG2)5 . The mechanisms underlying the activation of autoreactive B cells, however, are not well defined. To gain more insight into this autoimmune response we have characterized the binding of TG2 by a panel of human monoclonal antibodies generated by expression cloning of immunoglobulin genes from single plasma cells of the celiac disease lesion. The antibodies were highly specific to TG2 and bound preferentially to the “open”, Ca2+-activated enzyme conformation. Epitope mapping revealed that they recognize few distinct conformational epitopes that cluster in the N-terminal half of the enzyme. Two of the epitopes were overlapping with the fibronectin binding site in TG2, and none of the epitopes was accessible when TG2 was in a cell surfacebound form. Based on our findings we propose that the autoantibodies are generated against the soluble, catalytically active enzyme, whereas antibodies reactive with cell surfaceassociated TG2 are absent from the response due to negative selection of B cells recognizing membrane-bound self-antigen. The findings give insight into the mechanisms controlling the formation of anti-TG2 autoantibodies in celiac disease. The final version of this research has been published in Journal of Immunology. © 2013 American Association of Immunologist

Manajemen sumber daya manusia strategis

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