Hunting for cultivable Micromonospora strains in soils of the Atacama Desert

Innovative procedures were used to selectively isolate small numbers of Micromonospora strains from extreme hyper-arid and high altitude Atacama Desert soils. Micromonosporae were recognised on isolation plates by their ability to produce filamentous microcolonies that were strongly attached to the agar. Most of the isolates formed characteristic orange colonies that lacked aerial hyphae and turned black on spore formation, whereas those from the high altitude soil were dry, blue-green and covered by white aerial hyphae. The isolates were assigned to seven multi- and eleven single-membered groups based on BOX-PCR profiles. Representatives of the groups were assigned to either multi-membered clades that also contained marker strains or formed distinct phyletic lines in the Micromonospora 16S rRNA gene tree; many of the isolates were considered to be putatively novel species of Micromonospora. Most of the isolates from the high altitude soils showed activity against wild type strains of Bacillus subtilis and Pseudomonas fluorescens while those from the rhizosphere of Parastrephia quadrangulares and from the Lomas Bayas hyper-arid soil showed resistance to UV radiation

Actinoplanes siamensis sp. nov., isolated from soil

A Gram-positive filamentous bacterial strain that developed large campanulate sporangia at the ends of sporangiophores on substrate mycelium was isolated from bamboo forest soil in Thailand. According to the results of a polyphasic taxonomic study, our isolate had typical characteristics of members of the genus Actinoplanes. The 16S rRNA gene sequence analysis also indicated that strain A-T 6646<sup>T</sup> belonged to the genus Actinoplanes, being most closely related to Actinoplanes liguriensis DSM 43865<sup>T</sup> (97.61 %) and Actinoplanes octamycinicus NBRC 14524<sup>T</sup> (97.52 %). The DNA-DNA relatedness values, which differentiate the new strain from the most closely related species, were significantly below 70 %. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars contained xylose and arabinose. The predominant menaquinone was MK-9(H<sub>4</sub>). The diagnostic phospholipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol. The predominant cellular fatty acids were iso-C<sub>16: 0</sub>, anteiso-C<sub>17: 0</sub>, iso-C<sub>15: 0</sub> and anteiso-C<sub>15: 0</sub>. Following an evaluation of phenotypic, chemotaxonomic and genotypic studies, the isolate is proposed to represent a novel species to be named Actinoplanes siamensis sp. nov. The type strain is A-T 6646<sup>T</sup> (= BCC 46194<sup>T</sup> = NBRC 109076<sup>T</sup>). 2013 IUM

Planobispora takensis sp. nov., isolated from soil

A novel Gram-stain-positive, filamentous bacterial strain (A-T 7458<sup>T</sup>) was isolated from soil collected from hill evergreen forest in Thailand. The strain developed cylindrical sporangia containing a longitudinal pair of motile spores, on short ramifications of aerial mycelia. From a taxonomic study using a polyphasic approach, strain A-T 7458<sup>T</sup>had typical characteristics of members of the genus Planobispora. 16S rRNA gene sequence analysis indicated that the isolate was closely related to Planobispora siamensis A-T 4600<sup>T</sup>(98.5 %), Planobispora rosea JCM 3166<sup>T</sup>(97.6 %) and Planobispora longispora NBRC 13918<sup>T</sup>(97.6 %). The DNA-DNA relatedness values, which differentiated the novel strain from the closest species, were significantly below 70 %. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars contained ribose, madurose, mannose and glucose. The predominant menaquinone was MK-9(H<sub>2</sub>). The diagnostic phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylinositol, phosphatidylinositol-mannoside and aminophosphoglycolipid. The predominant cellular fatty acids were unsaturated C<sub>17:1</sub> and C<sub>18:1</sub>, and saturated C<sub>16:0</sub> and C<sub>17:0</sub>. Following an evaluation of phenotypic, chemotaxonomic and genotypic characteristics, the novel isolate is proposed to represent a novel species of the genus Planobispora, to be named Planobispora takensis sp. nov. The type strain is A-T 7458<sup>T</sup>(=BCC 48396<sup>T</sup>=NBRC 109077<sup>T</sup>). 2014 IUM