The Metagenome of an Anaerobic Microbial Community Decomposing Poplar Wood Chips

This study describes the composition and metabolic potential of a lignocellulosic biomass degrading community that decays poplar wood chips under anaerobic conditions. We examined the community that developed on poplar biomass in a non-aerated bioreactor over the course of a year, with no microbial inoculation other than the naturally occurring organisms on the woody material. The composition of this community contrasts in important ways with biomass-degrading communities associated with higher organisms, which have evolved over millions of years into a symbiotic relationship. Both mammalian and insect hosts provide partial size reduction, chemical treatments (low or high pH environments), and complex enzymatic ‘secretomes’ that improve microbial access to cell wall polymers. We hypothesized that in order to efficiently degrade coarse untreated biomass, a spontaneously assembled free-living community must both employ alternative strategies, such as enzymatic lignin depolymerization, for accessing hemicellulose and cellulose and have a much broader metabolic potential than host-associated communities. This would suggest that such a community would make a valuable resource for finding new catalytic functions involved in biomass decomposition and gaining new insight into the poorly understood process of anaerobic lignin depolymerization. Therefore, in addition to determining the major players in this community, our work specifically aimed at identifying functions potentially involved in the depolymerization of cellulose, hemicelluloses, and lignin, and to assign specific roles to the prevalent community members in the collaborative process of biomass decomposition. A bacterium similar to Magnetospirillum was identified among the dominant community members, which could play a key role in the anaerobic breakdown of aromatic compounds. We suggest that these compounds are released from the lignin fraction in poplar hardwood during the decay process, which would point to lignin-modification or depolymerization under anaerobic conditions

Limited effect of screening for depression with written feedback in outpatients with diabetes mellitus: a randomised controlled trial

Item does not contain fulltextAIMS/HYPOTHESIS: The aim of this study was to test the effectiveness of a screening procedure for depression (SCR) vs care as usual (CAU) in outpatients with diabetes. The primary outcome measured was depression score and the secondary outcomes were mental healthcare consumption, diabetes-distress and HbA(1c). MATERIALS AND METHODS: In a multicentre parallel randomised controlled trial, 223 outpatients with diabetes, who had an elevated depression score, were randomly assigned to SCR (n = 116) or CAU (n = 107), using computer generated numbers. SCR-patients were invited for a Composite International Diagnostic Interview (CIDI) to diagnose depression and/or anxiety (interviewers were not blinded for group assignment). As part of the intervention, patients and their physicians were informed of the outcome of the CIDI in a letter and provided with treatment advice. At baseline and 6 month follow-up, depression and diabetes-distress were measured using the Centre for Epidemiologic Studies Depression Scale (CES-D) and the Problem Areas in Diabetes survey (PAID). HbA(1c) levels were obtained from medical charts. RESULTS: Mean CES-D depression scores decreased from baseline to 6 months in both groups (24 +/- 8 to 21 +/- 8 [CAU] and 26 +/- 7 to 22 +/- 10 [SCR] respectively [p < 0.001]), with no significant differences between groups. Neither diabetes-distress nor HbA(1c) changed significantly within and between groups. The percentage of patients receiving mental healthcare increased in the SCR group from 20% to 28%, compared with 15% to 18% in the CAU group. CONCLUSIONS/INTERPRETATION: Depression screening with written feedback to patient and physician does not improve depression scores and has a limited impact on mental healthcare utilisation, compared with CAU. It appears that more intensive depression management is required to improve depression outcomes in patients with diabetes