The anaerobe Desulfovibrio desulfuricans ATCC 27774 grows at nearly atmospheric oxygen levels

AbstractSulfate reducing bacteria of the Desulfovibrio genus are considered anaerobes, in spite of the fact that they are frequently isolated close to oxic habitats. However, until now, growth in the presence of high concentrations of oxygen was not reported for members of this genus. This work shows for the first time that the sulfate reducing bacterium Desulfovibrio desulfuricans ATCC 27774 is able to grow in the presence of nearly atmospheric oxygen levels. In addition, the activity and expression profile of several key enzymes was analyzed under different oxygen concentrations

Soil biochemistry and microbial activity in vineyards under conventional and organic management at Northeast Brazil.

The São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that orgThe São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that organic fertilization can improve soil quality, we compared the effects of conventional and organic soil management on microbial activity and mycorrhization of seedless grape crops. We measured glomerospores number, most probable number (MPN) of propagules, richness of arbuscular mycorrhizal fungi (AMF) species, AMF root colonization, EE-BRSP production, carbon microbial biomass (C-MB), microbial respiration, fluorescein diacetate hydrolytic activity (FDA) and metabolic coefficient (qCO2). The organic management led to an increase in all variables with the exception of EE-BRSP and qCO2. Mycorrhizal colonization increased from 4.7% in conventional crops to 15.9% in organic crops. Spore number ranged from 4.1 to 12.4 per 50 g-1 soil in both management systems. The most probable number of AMF propagules increased from 79 cm-3 soil in the conventional system to 110 cm-3 soil in the organic system. Microbial carbon, CO2 emission, and FDA activity were increased by 100 to 200% in the organic crop. Thirteen species of AMF were identified, the majority in the organic cultivation system. Acaulospora excavata, Entrophospora infrequens, Glomus sp.3 and Scutellospora sp. were found only in the organically managed crop. S. gregaria was found only in the conventional crop. Organically managed vineyards increased mycorrhization and general soil microbial activity

Physical properties of strontium barium niobate thin films prepared by polymeric chemical method

Randomly oriented Sr0.75Ba0.25Nb2O6 thin films have been deposited on Pt(111)/Ti/SiO2/Si substrates using a polymeric chemical method to study their physical properties. Refinements of the structure confirm the stoichiometry of the studied films. The relaxor behavior is evidenced by the dielectric measurements and Vögel-Fulcher analysis of the dielectric curves. Lowering the transition temperature (Tm) by about 100 K and asymmetries in the local hysteresis loops well above Tm are discussed in terms of the existence of complex defects in thin films. © 2016 Taylor & Francis Group, LLC