Microbial community structure in polluted marine sediments determined by culture-independent methods

BASILE LA, LOZADA M, LUZZATTO D, FIGUEROLA E, PENCHASZADEH P, ERIJMAN L.

San Carlos de Bariloche

Congreso; XXXIX Reunión anual – Sociedad argentina de investigaciones en bioquímica y biología molecular (SAIB); 2003

SAIB

Knowledge about the microbial community structure in polluted marine sediments is required to develop tools for predicting and monitoring natural attenuation. We have conducted culture-independent profiling of microbial communities present in heavily polluted sediments in the Mar del Plata harbor area. Surface sediment samples from at a depth of 10-20 m, were collected with a dredge in five sampling stations, representative of different kind of pollution. A procedure based on dipersion, separation and filtration, combined with DAPI staining, was used for enumeration of total cells in all sampled sediments. The number of DAPI-detected bacterium-like particles ranged from 4,7x108 to 6.9x1010 per g of sediment. Bead mill homogenization in the presence of a phosphate-buffered containing SDS, followed by agarose gel electrophoresis in the presence of polyvinylpyrrolydone (PVP) was used for DNA recovery and removal of PCR inhibitors from crude extracts. Numerical comparison of 16S ribosomal DNA (rDNA)-based denaturing gradient gel electrophoresis (DGGE) profiles of Bacteria and Archaea was used to analyse the microbial community structures. Sequencing of cloned bands complemented DGGE data. Comparison of 16S rDNA profiles from polluted and nonpolluted sediments points to the relationship between microbial diversity and the degree and kind of pollution.