C-labeled ribosomal ribonucleic acid (rRNA) was prepared from NCIB 8002, 8A, NCIB 8636, WR 30, NCIB 8712, and ATCC 29145. These rRNA's were hybridized under stringent conditions with filter-fixed deoxyribonucleic acid from a great variety of gram-negative bacteria. Each hybrid was described by: (i) the temperature at which 50% of the hybrid was denatured, and (ii) the percent rRNA binding (amount in micrograms of rRNA duplexed to 100 μg of deoxyribonucleic acid). These data were used to construct rRNA similarity maps. The following conclusions could be drawn concerning rRNA cistron similarities. (i) Bacterial genera with free-living, aerobic, nitrogen-fixing members are very diverse and belong to different rRNA superfamilies. The present family is not a biological unit, and its status as a family is highly questionable. (ii) , and belong in the genus . Any synonymy of these names remains to be determined. , and constitute independent branches, which are about equidistant from and section I of as presented in , 8th ed. , and are located in the same rRNA superfamily. (iii) The genus appears to be rather heterogeneous. Its closest relatives appear to be , the authentic rhodopseudomonads, and some other organisms. These organisms belong in the same rRNA superfamily as , and . (iv) belongs in still another rRNA superfamily, together with , the and groups, , and a few other taxa. (v) The following organisms were generically misnamed: “” ATCC 12523, 301, ATCC 12417, CCEB 513, and (all strains examined).


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error