%0 Journal Article %A POTTS*, THOMAS V. %A BERRY, ELAINE M. %T Deoxyribonucleic Acid-Deoxyribonucleic Acid Hybridization Analysis of Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus %D 1983 %J International Journal of Systematic and Evolutionary Microbiology, %V 33 %N 4 %P 765-771 %@ 1466-5034 %R https://doi.org/10.1099/00207713-33-4-765 %I Microbiology Society, %X Deoxyribonucleic acids (DNAs) were isolated and purified from 20 strains of Actinobacillus actinomycetemcomitans, 6 strains of Haemophilus aphrophilus, 2 strains of Haemophilus paraphrophilus, 2 strains of Haemophilus pleuropneumoniae, 2 strains of Haemophilus paraphrohaemolyticus, 2 strains of Haemophilus influenzae, and 1 strain each of Actinobacillus lignieresii, Actinobacillus suis, Haemophilus aegyptius, Haemophilus parainfluenzae, and Haemophilus parahaemolyticus. The guanine-plus-cytosine contents of the DNAs were determined, and they agreed closely with previous estimates. DNA-DNA hybridization analyses revealed that all of the strains identified as A. actinomycetemcomitans were at least 69% homologous to DNA probes from two A. actinomycetemcomitans strains (strains NCTC 9710T [T = type strain] and Y4). The H. aphrophilus and H. paraphrophilus strains were homologous to the two A. actinomycetemcomitans probes at levels of 25 to 37%. The DNAs of all A. actinomycetemcomitans strains were homologous to a DNA probe from H. aphrophilus strain NCTC 5906 at levels of 30 to 39%. The two strains of H. paraphrophilus tested were homologous to the H. aphrophilus probe at levels of 73 and 77%, indicating a very close relationship between these groups of organisms. H. parainfluenzae strain ATCC 9796 DNA seemed to be homologous to the H. aphrophilus and A. actinomycetemcomitans probes at low but significant levels (12 to 16%). All of the other strains of haemophili and actinobacilli tested gave 10% or less homology with the three test probes. %U https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/00207713-33-4-765