STRUCTURE AND PERFORMANCE OF ELECTRO-ACTIVE BACTERIAL COMMUNITIES IN MICROBIAL FUEL CELLS UNDER VARYING OPERATING CONDITIONS

International audienceMicrobial Fuel Cells (MFCs) are being developed as a novel biotechnology to harvest energy from dissolved organic matter with potential applications ranging from wastewater treatment to power sources for remote environmental sensors. The objective of this work was to assess the role of operating conditions on the taxonomic structure and function (i.e., electricity production) of electro-active bacterial communities developing at the surface of the electrodes. Parameters tested included substrates (domestic wastewater, starch, glucose, acetate, lactate and LB medium), organic loads, feeding mode (batch and continuous mode) electrical conductivity of the system (open and close circuits), external resistances, and electrode composition and architecture. All experiments were performed using single chamber MFCs fed with primary clarifier effluent from a municipal wastewater treatment plant. Electrical performances (voltage, power) were determined throughout the different experiments. Community structure analyses were performed using RISA and 16S-rRNAbased phylogenetic microarrays. Results show that bacterial communities responsible for electricity production are markedly different from the inoculum (wastewater) and planktonic communities and from other compartments in the MFC. Communities are influenced by operating conditions and the presence of additional carbon sources, but remain relatively stable through time under given operating conditions. Correlations between bacterial community structure and substrates (nature and concentration) were observed, as well as between substrate concentration and electricity production. Interestingly, experiments conducted with different external resistances and with close and open circuits (i.e., electrons allowed to flow or not between the electrodes) showed the structure of electro-active bacterial communities is driven by electricity production

Flow around an oscillating grid in water and shear-thinning polymer solution at low Reynolds number

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Mice lacking the serotonin Htr2B receptor gene present an antipsychotic-sensitive schizophrenic-like phenotype

Impulsivity and hyperactivity share common ground with numerous mental disorders, including schizophrenia. Recently, a population-specific serotonin 2B (5-HT2B) receptor stop codon (ie, HTR2B Q20*) was reported to segregate with severely impulsive individuals, whereas 5-HT2B mutant (Htr2B−/−) mice also showed high impulsivity. Interestingly, in the same cohort, early-onset schizophrenia was more prevalent in HTR2B Q*20 carriers. However, the putative role of 5-HT2B receptor in the neurobiology of schizophrenia has never been investigated. We assessed the effects of the genetic and the pharmacological ablation of 5-HT2B receptors in mice subjected to a comprehensive series of behavioral test screenings for schizophrenic-like symptoms and investigated relevant dopaminergic and glutamatergic neurochemical alterations in the cortex and the striatum. Domains related to the positive, negative, and cognitive symptom clusters of schizophrenia were affected in Htr2B−/− mice, as shown by deficits in sensorimotor gating, in selective attention, in social interactions, and in learning and memory processes. In addition, Htr2B−/− mice presented with enhanced locomotor response to the psychostimulants dizocilpine and amphetamine, and with robust alterations in sleep architecture. Moreover, ablation of 5-HT2B receptors induced a region-selective decrease of dopamine and glutamate concentrations in the dorsal striatum. Importantly, selected schizophrenic-like phenotypes and endophenotypes were rescued by chronic haloperidol treatment. We report herein that 5-HT2B receptor deficiency confers a wide spectrum of antipsychotic-sensitive schizophrenic-like behavioral and psychopharmacological phenotypes in mice and provide first evidence for a role of 5-HT2B receptors in the neurobiology of psychotic disorder