Molecular-genetic and Chemotaxonomic Studies on Actinomadura and Nocardiopsis

Abstract

The relationships of 24 strains of 13 species of Actinomadura and 4 strains of Nocardiopsis dassonvillei were determined by nucleic acid hybridization studies. DNA-rRNA cistron similarity and DNA homology values reveal that Actinomadura is genetically heterogeneous. One cluster contained the type species Actinomadura madurae, Actinomadura pelletieri, Actinomadura verrucosospora, Actinomadura malachitica, Actinomadura citrea and 'Actinomadura kijaniata'. A second cluster embraced Actinomadura pusilla, Actinomadura roseoviolacea, Actinomadura libanotica, Actinomadura roseola and Actinomadura ferruginea. The internal homogeneity of the two Actinomadura clusters was demonstrated by a high similarity in the menaquinone and fatty acid composition of the strains enclosed. Actinomadura spadix, Actinomadura spiralis, and two strains of Actinomadura madurae were found to be unrelated to each other and could not be allocated to one of the two major Actinomadura clusters. Nocardiopsis dassonvillei was genetically and phenotypically clearly separated from all Actinomadura species investigated.

Nonomuraea jiangxiensis sp. nov., isolated from acidic soil

“…These values are well below the 70 % cut-off point for assigning strains to the same species (Stackebrandt & Goebel, 1994). Previous studies have shown that members of the genus Nonomuraea that exhibit high 16S rRNA gene sequence similarity (ranging from 97.6 to 99.4 %) can exhibit low DNA-DNA relatedness (Fischer et al, 1983;Poschner et al, 1985;Stackebrandt et al 2001; Kämpfer et al, 2005); therefore, DNA-DNA hybridizations were not carried out between strain FXJ1.102 T and other members of the genus Nonomuraea.The morphological, chemotaxonomic and phylogenetic data clearly support the assignment of strain FXJ1.102 T to the genus Nonomuraea, but the physiological characters and DNA-DNA relatedness demonstrate that the strain can be differentiated from its closest relatives in the genus Nonomuraea. Therefore, on the basis of genotypic and phenotypic evidence, strain FXJ1.102 T represents a novel species of the genus Nonomuraea, for which the name Nonomuraea jiangxiensis sp.…”

“…These values are well below the 70 % cut-off point for assigning strains to the same species (Stackebrandt & Goebel, 1994). Previous studies have shown that members of the genus Nonomuraea that exhibit high 16S rRNA gene sequence similarity (ranging from 97.6 to 99.4 %) can exhibit low DNA-DNA relatedness (Fischer et al, 1983;Poschner et al, 1985;Stackebrandt et al 2001;Kämpfer et al, 2005); therefore, DNA-DNA hybridizations were not carried out between strain FXJ1.102 T and other members of the genus Nonomuraea.…”

New Strategies for the Selective Isolation of Industrially Important Bacteria

“…Now that several major lines of descent leading to recent actinomycetes have been detected (Fischer, Kroppenstedt and Stackebrandt, 1983;Stackebrandt and Schleifer, 1984;Fowler, Ludwig and Stackebrandt, 1985), representative strains are the subject of extensive study using a variety of methods designed to elucidate the fine structure of the higher taxa. The product of such comparative studies will be a stable classification of the actinomycetes.…”

Nonomuraea monospora sp. nov., an actinomycete isolated from cave soil in Thailand, and emended description of the genus Nonomuraea

“…Strains belonging to the same species generally have sequence similarities of .98.7 % (Stackebrandt & Ebers, 2006). However, 16S rRNA gene sequence similarities of 97.1-100 % have been reported between several Nonomuraea species that, in the corresponding hybridization experiments, showed low DNA-DNA relatedness values (Fischer et al, 1983;Poschner et al, 1985;Stackebrandt et al, 2001). For example, Nonomuraea kuesteri GW 14-1925 T and Nonomuraea turkmeniaca DSM 43926 T were found to have a 16S rRNA gene sequence similarity of 98.9 % but a DNA-DNA relatedness value of only 40.5 % (Kämpfer et al, 2005).…”

“…The genus was created, on the basis of data on spore formation and 16S rRNA gene sequences, to hold some spore-forming species that had initially been placed in the genera Actinomadura (Fischer et al, 1983;Athalye et al, 1985;Poschner et al, 1985) and Microtetraspora (Kroppenstedt et al, 1990). At the time of writing, the genus comprises 27 species (Gyobu & Miyadoh, 2001;Stackebrandt et al, 2001;Quintana et al, 2003;Ara et al, 2007a, b;Le Roes & Meyers, 2008;Kämpfer et al, 2010;Li et al, 2011;Wang et al, 2011;Xi et al, 2011;Zhao et al, 2011); Nonomuraea pusilla is the type species.…”