Vibrio harveyi, one of the best characterized model organisms in QS, was used to address the question how single cells behave within a QS-activated community in a homogeneous environment. Analysis of the QS-regulated bioluminescence of a wild type strain revealed that even at high cell densities only 69% of the Linsitinib purchase cells of the population produced bioluminescence, 25% remained dark and 6% were dead. Moreover, light intensities greatly varied

from cell to cell at high population density. Addition of autoinducer to a bright liquid culture of V. harveyi increased the percentage of luminescent cells up to 98%, suggesting that V. harveyi produces and/or keeps the autoinducers at non-saturating concentrations. In contrast, all living cells of a constitutive QS-active mutant (Delta luxO) produced light. We also found that QS affects biofilm formation in V. harveyi. Our data provide first evidence that a heterogeneous FG-4592 concentration population produces more biofilm than a homogeneous one. It is suggested that even a QS-committed population of V. harveyi takes advantage of heterogeneity, which extends the current view of QS-regulated uniformity.”
“Background and Aims: Dipeptidyl peptidase-4 (DPP-4) inhibitors block the degradation of glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide.

The aim of the present study was to quantitatively assess the incretin effect after treatment with the DPP-4 inhibitor vildagliptin (V) or placebo (P) in patients with type 2 diabetes.\n\nMaterials and Methods: Twenty-one patients (three women, 18 men) with type 2 diabetes previously treated with metformin (mean age, 59 yr; body mass index, 28.6 kg/m(2); glycosylated hemoglobin, 7.3%) were studied in a two-period crossover design. They received 100 mg V once daily or P for 13 d in randomized order. The incretin effect was measured on d 12 (75-g oral glucose) and d 13 (“isoglycemic” iv glucose) based on insulin and C-peptide determinations and insulin secretion rates (ISR).\n\nResults: V relative to P treatment significantly increased intact

incretin concentrations after oral glucose and insulin secretory responses to both oral glucose and isoglycemic iv glucose (e.g. AUC(ISR) (oral), by 32.7%, P = 0.0006; AUC(ISR iv), by 33.1%, P = 0.01). The numerical Selleck U0126 incretin effect was not changed (IEISR, V vs. P, 35.7 +/- 4.9 and 34.6 +/- 4.0%, P = 0.80).\n\nConclusions: DPP-4 inhibition augmented insulin secretory responses both after oral glucose and during isoglycemic iv glucose infusions, with no net change in the incretin effect. Thus, slight variations in basal incretin levels may be more important than previously thought. Or, DPP-4 inhibitor-induced change in the incretin-related environment of islets may persist overnight, augmenting insulin secretory responses to iv glucose as well. Alternatively, yet unidentified mediators of DPP-4 inhibition may have caused these effects.