Deoxyribonucleic Acid Relationships Among Hydrogen-Oxidizing Strains of the Genera Pseudomonas, Alcaligenes, and Paracoccus

Abstract

Optical determination of deoxyribonucleic acid (DNA)-DNA reassociation kinetics was applied to the classification of 32 selected strains of hydrogen-oxidizing bacteria belonging to the genera Pseudomonas, Alcaligenes, and Paracoccus. The renaturation studies revealed a high intraspecies DNA homology for some strains of the species Pseudomonas palleronii, Pseudomonas pseudoflava, and Alcaligenes paradoxus, supporting former taxonomic concepts of different authors. The 12 denitrifying strains belonging to the genus Paracoccus were shown to be interrelated at various levels of percent degree of binding, and at least two clusters of very high genome-DNA relatedness have been found. DNA-DNA reassociation kinetics were also used for the calculation of the average molecular weight of genome DNA. The genome molecular weight of the hydrogen-oxidizing bacteria investigated in this study ranged from 3 X 109 to 5 X 109.