Differentiation of Thermophilic Anaerobic Gram-positive Bacteria by Random Amplified Polymorphic DNA Analysis.

Abstract

Random amplified polymorphic DNA (RAPD) analysis was applied to the differentiation of 11 thermophilic clostridia species, 11 type strains and 14 reference strains, at the species level. The 6 primers used in amplification generated 2 to 11 bands with 170-3,300 bp that were different depending on each of the strains and the primers used. From a comparison of RAPD fingerprints: sizes, numbers, and intensities of bands, it was demonstrated that (Clostridium) thermocellum, (Clostridium) thermolacticum, Moorella thermoacetica, and Thermoanaerobacterium thermosaccharolyticum were genotypically homogeneous at each species level. Each species showed species-specific and -common bands in RAPD profiles that were most pertinent for the discrimination of strains at the species level. In contrast, it was shown that each species of Thermoanaerobacter thermohydrosulfuricus, Thermoanaerobacter thermocopriae and Thermoanaerobacterium thermosulfurigenes was genotypically heterogeneous because none of the 6 primers produced species-common band patterns. However, each type strain of thermophilic clostridia species gave different RAPD fingerprints with each primer. Results obtained by the RAPD analysis therefore complement and support the current classification of these species and this study also shows that RAPD has the potential to differentiate between these species.