Isolation and characterization of bacteria from a brazilian gold mining area with a capacity of arsenic bioaccumulation.

In Paracatu, a city in Minas Gerais State (Brazil), the gold mineral extraction produces wastes that contribute to environmental contamination by arsenic. This work describes the evaluation of arsenic concentration from soil of a gold mining area in Paracatu and the selection of arsenic resistant bacteria. In the process of culturing enrichment, 38 bacterial strains were isolated and the minimum inhibitory concentration (MIC) was determined in solid medium for each strain. Three bacterial strains named P1C1Ib, P2Ic and P2IIB were resistant to 3000 mg L-1 of arsenite. Analysis of 16S rDNA gene sequences revealed that these bacteria belong to Bacillus cereus and Lysinibacillus boronitolerans species. After cultivation of the strains P1C1Ib, P2Ic and P2IIIb, 69.38%-71.88% of arsenite and 82.39%-85.72% of arsenate concentrations were reduced from the culture medium, suggesting the potential application of theses strains in bioremediation processes.

Multiple-Biomarker Approach in a Commercial Marine Scallop from San Jose gulf (Patagonia, Argentina) for Health Status Assessment.

The health status of the commercial Tehuelche scallop Aequipecten tehuelchus from San Román and El Riacho in San José gulf (Patagonia, Argentina) was evaluated through biomarkers widely used in ecotoxicological applications. Natural levels of arsenic (As) and cadmium (Cd) were measured to determine their potential relationships with fluctuations of several oxidative stress biomarkers in the scallop. Oxidative biomarkers, such as catalase (CAT), glutathione S-transferase (GST), superoxide dismutase (SOD), metallothioneins (MT), reactive oxygen species (ROS), α-tocopherol (α-T), and lipid peroxidation (LPO) through thiobarbituric acid reactive substances (TBARS) and lipid radical (LR∙), were measured in gills, digestive gland, and muscle of Tehuelche scallop in winter (August 2015) and summer (January 2016). Levels of As and Cd and of most of the biomarkers (SOD, ROS, TBARS, and LR∙) showed strong seasonal variability in the three tissues. In general, the highest values were recorded in digestive gland. The Integrated Biomarker Response index indicated that the most stressed condition of A. tehuelchus was in summer in San Román. Additionally, the Integrated Biomarker Response index showed a strong relationship among tissues and As and Cd accumulation. This kind of approach could be used as an integrated tool to identify the health status of scallop A. tehuelchus from San José gulf.