02190nam a2200205 a 450000100080000000500110000800800410001910000260006024501080008626001210019430000090031552015170032465000180184165000090185965000260186870000200189470000180191470000250193270000270195721635092024-04-11       2004    bl uuuu     u00u1 u    #d1 aSILVA, M. R. S. S. da  aEffects of land use changes on soil microbial communities in the Cerrado region.h[electronic resource]  aIn: CONFERÊNCIA CIENTÍFICA DO LBA, 3., 2004, Brasília, DF. Anais de trabalhos completos. Brasília, DF: LBAc2004  a1 p.  aThe composition and activity of soil microbial communities largely determine biogeochemical cycles, the turnover process of organic matter, and the fertility and quality of solis. Plant communities can influence associated soil microbial communities through the types and amounts of C and nutrients inputs by altering the temperature and water content of the soil. The intensification of agricultural activities in the Cerrado region (savannas of Central Brazil) results in the replacement of native vegetation cover, changes in fire regime and soil physical and chemical properties. As most of soil microorganisms cannot be characterized by conventional cultivation techniques, after soil DNA extraction we used DGGE (Denaturing Gradient Gel Electrophoresis) to investigate soil microbial communities through the comparison of band patterns. Soil samples were taken from 0-5 cm depth in native Cerrado areas (campo sujo and cerrado restricted sense) and in pasture areas. The burned and unburned plots of the two native vegetation types were sampled 2, 10 and 30 days after burning. The samples were collected during the wet and dry season as well as during the transition wet to dry season. Soil DNA was obtained by direct DNA extraction and was amplified by PCr using 16S primers, U968f and L1401r. The comparison of band patterns (amount, position and intensity of bands) indicates significant differences between native and pasture sites and between seasons (wet and dry) and between unburned native áreas.  aCerrado soils  aLand  aMicrobial communities1 aBRESOLIN, J. D.1 aKRUGER, R. H.1 aBUSTAMANTE, M. M. C.1 aREIS JUNIOR, F. B. dos