A representative genomic 16S rRNA sequence of S. azurea
was compared using NCBI BLAST [16
] under default settings (e.g., considering only the high-scoring segment pairs (HSPs) from the best 250 hits) with the most recent release of the Greengenes database [18
] and the relative frequencies of taxa and keywords (reduced to their stem [19
]) were determined, weighted by BLAST scores. The most frequently occurring genera were Saccharomonospora
(6.0%) and Prauserella
(5.5%) (176 hits in total). Regarding the eight hits to sequences from members of the species, the average identity within HSPs was 99.5%, whereas the average coverage by HSPs was 99.8%. Regarding the 42 hits to sequences from other members of the genus, the average identity within HSPs was 97.0%, whereas the average coverage by HSPs was 98.3%. Among all other species, the one yielding the highest score was Saccharomonospora xinjiangensis
(AJ306300), which corresponded to an identity of 98.9% and an HSP coverage of 100.1%. (Note that the Greengenes database uses the INSDC (= EMBL/NCBI/DDBJ) annotation, which is not an authoritative source for nomenclature or classification.) The highest-scoring environmental sequence was FN667533 'stages composting process pilot scale municipal drum compost clone PS3734', which showed an identity of 100.0% and a HSP coverage of 97.9%. The most frequently occurring keywords within the labels of all environmental samples that produced hits were 'feedlot' (7.9%), 'top' (4.1%), 'beef, cattl, coli, escherichia, habitat, marc, neg, pen, primari, secondari, stec, surfac, synecolog' (3.9%), 'feedbunk' (2.3%) and 'compost' (1.7%) (74 hits in total). Environmental samples that yielded hits of a higher score than the highest scoring species were not found.
shows the phylogenetic neighborhood of S. azurea in a 16S rRNA based tree. The sequences of the three identical 16S rRNA gene copies in the genome do not differ from the previously published 16S rRNA sequence (Z38017).
Figure 1 Phylogenetic tree highlighting the position of S. azurea relative to the type strains of the other species within the family Pseudonocardiaceae. The tree was inferred from 1,386 aligned characters [20,21] of the 16S rRNA gene sequence under the maximum (more ...)
Table 1 Classification and general features of S. azurea AN-128 T according to the MIGS recommendations .
Cells of S. azurea
form an irregularly branched vegetative mycelium of 0.3 to 0.4 μ
m diameter () [1
]. The monopodally branching aerial mycelium has a diameter of 0.3 to 0.6 μm [1
]; the mature mycelium and the spores are azure to cyaneus when grown on Oatmeal agar (ISP3) or on Czapek sucrose agar [1
]. Smooth, round spores are 0.8 to 1.0 mM long, mostly found on the aerial mycelium, but rarely on the substrate mycelium [1
]. No distinct soluble pigment was detectable [1
]. The growth range of strain NA-128T
spans from 24-40°C, with an optimum at 28-37°C [1
]. Strain NA-128T
grows well in up to 7% NaCl containing medium, but is inhibited at 10% NaCl [1
]. Physiological characteristics such as growth substrates, gelatin formation and peptonization of milk are described in detail by Runmao (1987) [1
Scanning electron micrograph of S. azurea AN-128T
The cell wall of strain AN-128T
-diaminopimelic acid. Galactose and arabinose are present, indicating a type IV cell wall / type A whole cell sugar pattern [1
]. The fatty acids spectrum is dominated by almost 80% hexadecanoic acids: iso-
(27.0%), C16:1 cis-9
(palmitic acid, 13.0%), iso-
]. There are no data available for polar lipids and quinines of this strain.