Regulation of Burkholderia cenocepacia virulence by the fatty acyl-CoA ligase DsfR as a response regulator of quorum sensing signal.

Quorum sensing (QS) is a cell-to-cell communication mechanism mediated by small diffusible signaling molecules. Previous studies showed that RpfR controls Burkholderia cenocepacia virulence as a cis-2-dodecenoic acid (BDSF) QS signal receptor. Here, we report that the fatty acyl-CoA ligase DsfR (BCAM2136), which efficiently catalyzes in vitro synthesis of lauryl-CoA and oleoyl-CoA from lauric acid and oleic acid, respectively, acts as a global transcriptional regulator to control B. cenocepacia virulence by sensing BDSF. We show that BDSF binds to DsfR with high affinity and enhances the binding of DsfR to the promoter DNA regions of target genes. Furthermore, we demonstrate that the homolog of DsfR in B. lata, RS02960, binds to the target gene promoter, and perception of BDSF enhances the binding activity of RS02960. Together, these results provide insights into the evolved unusual functions of DsfR that control bacterial virulence as a response regulator of QS signal.

Effects of Tai Chi on adiponectin and glucose homeostasis in individuals with cardiovascular risk factors.

The aim of this study was to evaluate the acute effect of a single bout of Tai Chi (TC) exercise on adiponectin and glucose homeostasis in individuals with cardiovascular risk factors. Twenty-six individuals (mean age 60.2 years) with at least one cardiovascular risk factor who had been practicing Yang's style TC exercise for at least 3 months were recruited from a regional hospital in Taiwan. A one-group repeated measured quasi-experimental design was used. Participants completed a 60-min Yang's style TC exercise routine including warm up, stretching exercises, and TC followed by a 30-min resting period. After a 1-week washout period, the same group of participants underwent a control condition in which they were instructed to remain seated for 90 min at the study location. Blood samples were collected both before and after the TC intervention or the sitting condition. The difference between pre-post measurements for adiponectin was 0.58 ± 1.42 µg/ml in the TC trial and -0.46 ± 0.99 µg/ml in the sitting trial. The differences between the two trials were statistically significant (P = 0.004). The changes from pretrial to posttrial were significantly greater for glycerol (P < 0.001), cholesterol (P = 0.046), and LDL-C (P = 0.038) in the TC trial compared with those in the sitting trial. Conversely, the changes were significantly lesser for HOMA-IR (P = 0.004), log (HOMA-IR) (P = 0.001), and glucose (P = 0.003) in TC trial compared with those in the sitting trial. In conclusion, a single bout of TC exercise had a significant positive effect on blood adiponectin concentrations in individuals with cardiovascular risk factors.