Recent investigation of the microbial communities in an oil reservoir using culture-independent molecular techniques has indicated that this environment contains many uncultured assemblages, and that the cultured bacteria may represent very minor components of the true microbial diversity. In this study, 16S rDNA based PCR amplification and denaturing gradient gel electrophoresis (PCR-DGGE) was used to monitor the microbial diversity in an injection well (12#9-11) and two related production wells (12#9-9S、1...