Role of TARP interaction in S-SCAM-mediated regulation of AMPA receptors

Scaffolding proteins are involved in the incorporation, anchoring, maintenance, and removal of AMPA receptors (AMPARs) at synapses, either through a direct interaction with AMPARs or via indirect association through auxiliary subunits of transmembrane AMPAR regulatory proteins (TARPs). Synaptic scaffolding molecule (S-SCAM) is a newly characterized member of the scaffolding proteins critical for the regulation and maintenance of AMPAR levels at synapses, and directly binds to TARPs through a PDZ interaction. However, the functional significance of S-SCAM–TARP interaction in the regulation of AMPARs has not been tested. Here we show that overexpression of the C-terminal peptide of TARP-γ2 fused to EGFP abolished the S-SCAM-mediated enhancement of surface GluA2 expression. Conversely, the deletion of the PDZ-5 domain of S-SCAM that binds TARPs greatly attenuated the S-SCAM-induced increase of surface GluA2 expression. In contrast, the deletion of the guanylate kinase domain of S-SCAM did not show a significant effect on the regulation of AMPARs. Together, these results suggest that S-SCAM is regulating AMPARs through TARPs.     

Presence of a small plasmid in clinical isolates of Streptococcus pneumoniae

Twenty-four of 63 enteric Gram-negative organisms (38.1%) which were isolated from 35 apparently healthy Nigerian students were found to have low trimethoprim resistance (MIC less than 1000 mg/l). These isolates were also found to be resistant to several other antibiotics and trimethoprim resistance was found to be transferable from 15 (62.5%) of the trimethoprim resistant organisms into E. coli EC 1005. It is likely that the high percentage of trimethoprim resistance encountered in this study is related to the high rate of resistance transfer which was observed.     

Functional Effects of Adiponectin on Endothelial Progenitor Cells

Adiponectin is an adipokine whose plasma levels are inversely correlated to metabolic syndrome components. Adiponectin protects against atherosclerosis and decreases risks in myocardial infarction. Endothelial progenitor cells (EPCs) are a heterogeneous population of circulating cells involved in vascular repair and neovascularization. EPCs number is reduced in patients with cardiovascular disease. We hypothesize that the positive effects of adiponectin against atherosclerosis are explained in part by its interactions with EPCs. Cells were obtained from healthy volunteers' blood by mononuclear cell isolation and plating on collagen‐coated dishes. Three sub‐populations of EPCs were identified and characterized using flow cytometry. EPCs' expression of adiponectin receptors, AdipoR1, and AdipoR2 was evaluated by quantitative PCR. The effects of recombinant adiponectin on EPCs' susceptibility to apoptosis were assessed. Finally, expression of neutrophil elastase by EPCs and activity of this enzyme on adiponectin processing were assessed. Quantitative PCR analysis of EPCs mRNAs showed that AdipoR1 mRNA is expressed at higher levels than AdipoR2. Expression of AdipoR1 protein was confirmed by western blot. Adiponectin significantly increased survival of two sub‐populations of EPCs in conditions of serum deprivation. Such effect could not be demonstrated in the third EPCs sub‐population. We also demonstrated that EPCs, particularly one sub‐population, express neutrophil elastase. Neutrophil elastase activity was confirmed in EPCs' conditioned media. Adiponectin protects some EPCs sub‐populations against apoptosis and therefore could modulate EPCs ability to induce repair of vascular damage. Neutrophil elastase activity of EPCs could locally modulate adiponectin activity by its involvement in the generation of the globular form of adiponectin.     

Personality,Relationship Conflict,and Teamwork-Related Mental Models

This study seeks to explore whether neuroticism, agreeableness, and conscientiousness moderate the influence of relationship conflict experienced in groups on changes in group members'' evaluative cognitions related to teamwork quality (teamwork-related mental models). Data from 216 students, nested in 48 groups were analyzed using a multilevel modeling approach. Our results show that the experience of relationship conflict leads to a negative shift from the pre-task to the post-task teamwork-related mental models. Moreover, the results indicate that conscientiousness buffered the negative association between relationship conflict and the change in teamwork-related mental models. Our results did not support the hypothesized moderating effect of agreeableness and show that the detrimental effect of relationship conflict on the shift in teamwork-related mental models is accentuated for group members scoring low rather than high on neuroticism. These findings open new research venues for exploring the association between personality, coping styles and change in teamwork-related mental models.