02337naa a2200445 a 450000100080000000500110000800800410001910000220006024500850008226000090016752011700017665000200134665000160136665000110138265000100139365000160140365000090141965000130142865000250144165000170146665000170148365000170150065000190151765000090153665000150154565000380156065000140159865000090161265000090162165300110163065300150164165300280165670000180168470000200170270000200172270000170174270000180175970000250177777300890180216210251999-04-19       1997    bl uuuu     u00u1 u    #d1 aHUDDLESTON, A. S.  aMolecular detection of streptomycin-producing streptomycetes in Brazilian soils.  c1997  aActinomycetes were isolated from soybean rhizosphere soil collected at two field sites in Brazil. All the isolates were identified as Streptomyces species and were screened for streptomycin production and the presence of two genes, strA and strB1, known to be involved in streptomycin biosynthesis in Streptomyces griseus. Antibiotic resistance profiles were determined for 53 isolates from cultivated and uncultivated sites, and approximately half the strains wre streptomycin resistant. Clustering by the unweighted pair group method with averages indicated the presence of two major clusters, with the majority of resistant strains from cultivated sites being placed in cluster 1. Only representatives from this cluster contained strA. Streptomycetes containing   strA and strB1 were phenotypically diverse, and only half could be assigned to known species. Sequence comparison of 16S rRNA and trpBA (tryptophan synthetase) genes revealed that streptomycin-producing streptomycetes were phylogenetically diverse. It appeared that a population of streptomycetes had colonized the rhizosphere and that a proportion of these were capable of streptomycin production.  aActinomycetales  aantibiotics  aBrazil  agenes  arhizosphere  asoil  asoybeans  aStreptomyces griseus  astreptomycin  aActinomiceto  aAntibiótico  aEstreptomicina  aGene  aProdução  aResistência a Produtos Químicos  aRizosfera  aSoja  aSolo  aBrasil  aProduction  aResistance to chemicals1 aCRESSWELL, N.1 aNEVES, M. C. P.1 aBERINGER, J. E.1 aBAUMBERG, S.1 aTHOMAS, D. I.1 aWELLINGTON, E. M. H.  tApplied and Environmental Microbiology, Washingtongv. 63, n. 4, p. 1288-1297, 1997.