Bacteroides thetaiotaomicron-derived outer membrane vesicles promote regulatory dendritic cell responses in health but not in inflammatory bowel disease

Background: Bacteroides thetaiotaomicron (Bt) is a prominent member of the human intestinal microbiota that, like all Gram-negative bacteria, naturally generates nanosized outer membrane vesicles (OMVs) which bud off from the cell surface. Importantly, OMVs can cross the intestinal epithelial barrier to mediate microbe-host cell crosstalk involving both epithelial and immune cells to help maintain intestinal homeostasis. Here we have examined the interaction between Bt OMVs and blood or colonic mucosa-derived dendritic cells (DC) from healthy individuals and patients with Crohn’s disease (CD) or ulcerative colitis (UC). Results: In healthy individuals, Bt OMVs stimulated significant (p<0.05) IL-10 expression by colonic DC, whereas in peripheral blood-derived DC they also stimulated significant (p<0.001 and p<0.01, respectively) expression of IL-6 and the activation marker CD80. Conversely, in UC Bt OMVs were unable to elicit IL-10 expression by colonic DC. There were also reduced numbers of CD103 + DC in the colon of both UC and CD patients compared to controls, supporting a loss of regulatory DC in both diseases. Furthermore, in CD and UC, Bt OMVs elicited a significantly lower proportion of DC which expressed IL-10 (p<0.01 and p<0.001, respectively) in blood compared to controls. These alterations in DC responses to Bt OMVs were seen in patients with inactive disease, and thus are indicative of intrinsic defects in immune responses to this commensal in inflammatory bowel disease (IBD). Conclusions: Overall, our findings suggest a key role for OMVs generated by the commensal gut bacterium Bt in directing a balanced immune response to constituents of the microbiota locally and systemically during health which is altered in IBD patients

Automobile Prices, Gasoline Prices, and Consumer Demand for Fuel Economy

The relationship between gasoline prices and the demand for vehicle fuel efficiency is important for environmental policy but poorly understood in the academic literature. We provide empirical evidence that automobile manufacturers price as if consumers respond to gasoline prices. We derive a reduced-form regression equation from theoretical micro-foundations and estimate the equation with nearly 300,000 vehicle-week-region observations over the period 2003-2006. We find that vehicle prices generally decline in the gasoline price. The decline is larger for inefficient vehicles, and the prices of particularly efficient vehicles actually rise. Structural estimation that ignores these effects underestimates consumer preferences for fuel efficiency

ELECTROCHEMICAL TREATMENT OF OILFIELD PRODUCED WATER

Oil production generates wastewater bearing oily hydrocarbons, referred to “produced water” (PW). PW from a heavy-oil field has been treated with stainless steel (SS) cathode and dimensionally stable anodes – passivated titanium and graphite. In the electrolytic cells with these electrodes, electrooxidation (EO) accompanied by electroflotation (EF) are the main processes leading to pollutants removal. An oxidation by in situ generated oxidizing agents is found as the most plausible mechanism for decomposition of oily hydrocarbons in the PW containing high concentration of chloride ions. Total oily hydrocarbons (TOH) content and chemical oxygen demand (COD) as integral parameters and gas chromatography / mass spectrometry as analytical method were used to evaluate the efficiency of the treatment. At the optimal conditions, 15 mA/cm2 and 15 min, 92.5 % removal of TOH and 25 % removal of COD have been achieved through energy consumption 2.218 kWh per kg removed TOH by the EO. Additionally, the treatment of PW in a cell having SS cathode and iron as sacrificial anode has been performed, where electrocoagulation (EC) supplemented by electroflotation cause decrease of organic contaminants concentration. At the optimum conditions, current density 10 mA/cm2 applied for 10 min (energy consumption 0.603 kWh/kg) or current density 8 mA/cm2 applied for 15 min (energy consumption 0.629 kWh/kg) the TOH removal of 95.4 % and 96.4 % respectively have been determined. EC/EF has been found to be more effective than the EO/EF for treating the PW polluted by high-molecular alkanes. The EC/EF is an environmentally friendly and efficient method