Intra- and Intergeneric Similarities of the Ribosomal Ribonucleic Acid Cistrons of Acinetobacter

Abstract

3H-labeled rRNA was prepared from Acinetobacter calcoaceticus ATCC 230ST and hybridized with filter-fixed DNA from carefully selected Acinetobacter strains, reference strains of taxonomically well-located genera, or some selected misnamed strains. The hybridization parameters, the temperature at which 50% of the hybrid was denatured (Tm(ej) and percent rRNA binding, were determined, The following conclusions can be drawn from the DNAxRNA hybridization results, the rRNA similarity map, and a Tm ( The genus Acinetobacter is not related to one of the well-established genera or families, nor is it a true member of one of the previously described rRNA superfamilies. The genus Acinetobacter forms a new and separate rRNA branch which is taxonomically slightly more close to rRNA superfamily 11 (Pseudomonas fluorescens complex, Azomonas, Azotobacter, etc.) than to rRNA superfamily I (Enterobacteriuceae, Vibrionaceae, Pasteurellaceae, etc.) and the genus Xanthomonas. (v) The misnamed species "Pseudomonas pavonacea" and "Pseudomonas cruciviae" belong to the Acinetobacter rRNA branch, although they differ from the genus Acinetobacter in several important phenotypic features.

The Phylogeny of the Genera Chryseomonas, Flavimonas, and Pseudomonas Supports Synonymy of These Three Genera

“…In contrast, NCTC 10693 is the strain which was originally characterized as "P. pavonaceae" by Levine and Soppeland (7). Therefore, the difference between our phylogenetic analysis results and the results reported by Van Landschoot et al (15) can be attributed to the difference in the strains used.…”

“…However, Van Landschoot et al (15) reported that "P. pavonaceae" NCTC 10693 belongs on the Acinetobacter rRNA branch. The genus Acinetobacter is a genus of the family MoraxeZlaceae (ll), and the Acinetobacter rRNA branch has been reported to be far from the P. fluorexens complex branch (11,15 was not available, but this strain was apparently isolated in the Laboratory of Fermentation and Microbiology, Faculty of Agriculture, University of Tokyo. In contrast, NCTC 10693 is the strain which was originally characterized as "P. pavonaceae" by Levine and Soppeland (7).…”

Inter- and Intrafamilial Similarities of rRNA Cistrons of the Pasteurellaceae

“…Some reference strains (Escherichia coli B, Vibrio parahaemolyticus ATCC 17802T [T = type strain], and Aerornonas hydrophila ATCC 7966T) from other well-known bacterial families were also included. Some of the strains used were grown on media described previously (75). Most strains belonging to the family Pasteurellaceae were grown primarily on chocolate agar (tryptic soy agar [Difco Laboratories] which after sterilization was supplemented with 5% [voVvol] sheep blood and was kept at 80°C for 15 min before pouring) in a moist atmosphere containing 5 to 10% carbon dioxide at 36°C.…”

Notes: Branhamaceae fam. nov., a Proposed Family To Accommodate the Genera Branhamella and Moraxella

“…The temperatures at which onehalf of the DNA-rRNA duplexes were denatured [T,,,, values] ranged between 74.5 and 79.5"C. Tm(e) provides a measure of the level of base sequence similarity between rRNA cistrons. Thus, the genus Acinetobacter is rather heterogeneous (53). The TmCe) values were 70.3 to 71.1"C for DNA-rRNA duplexes between the type strains of A .…”

“…cuniculi (48). Rossau et al (48) believed that the genera Moraxella and Branhamella are members of one genetic group which branches from the genus Acinetubacter at a Tl,l(e) level of 71.2 4 1.0"C. Van Landschoot et al (53) concluded that "the genus Acinetobacter is not related to one of the well-established genera or families." The T,+) value of 61.6"C determined for the duplex between the type strains of A .…”