Deoxyribonucleic acid relationship among the radiation-resistant Acinetobacter and other Acinetobacter.

Abstract

DNA-DNA hybridization was carried out to clarify the taxonomic relationship among the radiation-resistant Acinetobacter and other Acinetobacter strains. Twenty-six of the thirty-one strains examined were divided on the basis of DNA homology into five separate groups, but the other five strains were not allocated to any groups. Group 1 was composed of seven named strains from culture collections and four isolates together with the type strain of Acinetobacter calcoaceticus. Group 2 consisted of two named strains with the type strain of Acinetobacter lwoffii. Groups 3 and 4 consisted respectively of three named strains and one isolate. And group 5 consisted of the radiation-resistant strain FO-1 isolated from a cotton sample and two strains (G82012 and G82076) isolated from soil samples. The DNA of strain FO-1 showed less than 44% DNA homologies to the DNAs of the authentic Acinetobacter strains. On the other hand, the DNAs of strains G82012 and G82076 from soil showed respectively 92.0 and 91.1% DNA homologies to the DNA of strain FO-1. These two strains from soil were also resistant to gamma-rays. Therefore, it was concluded that these three radiation-resistant Acinetobacter strains were taxonomically separate from the other Acinetobacter species.