抄録
A rapid method for estimating the population densities of uncultured bacteria in the environment was developed. This method consists of (i) addition of particular bacterial cells of a known cell number to an environmental sample, (ii) PCR amplification of partial 16S rDNA fragments with a set of eubacterial universal primers, (iii) temperature gradient gel electrophoresis (TGGE) analysis of the PCR products, and (iv) densitometry of the TGGE pattern. The utility of this competitive PCR/TGGE (cPCR/TGGE) method was demonstrated in the analysis of dominant bacterial populations in seawater sampled from the Heita sound (Kamaishi, Iwate, Japan). The nucleotide-sequence analysis of the TGGE bands revealed that the dominant populations were closely related to previously characterized uncultured marine bacteria.