A denaturing gradient gel electrophoresis (DGGE) method for analyzing 16S rDNA of methanogenic archaeal community in paddy field soil is presented. Five specific primers for 16S rDNA of methanogenic archaea, which were modified from the primers for archaea, were first evaluated by polymerase chain reaction and DGGE using genomic DNAs of 13 pure culture strains of methanogenic archaea. The DGGE analysis was possible with two primer pairs (0348aF-GC and 0691R; 0357F-GC and 0691R) of the five pairs tested although 16S rDNA of some non-methanogenic archaea was amplified with 0348aF-GC and 0691R. These two primer pairs were further evaluated for use in analysis of methanogenic archaeal community in Japanese paddy field soil. Good separation and quality of patterns were obtained in DGGE analysis with both primer pairs. A total of 41 DNA fragments were excised from the DGGE gels and their sequences were determined. All fragments belonged to methanogenic archaea. These results indicate that the procedure of DGGE analysis with the primer pair 0357F-GC and 0691R is suitable for investigating methanogenic archaeal community in paddy field soil.

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