Micromonospora

Abstract Mi.cro.mo.no.spo'ra. Gr. adj. mikros small; Gr. adj. monos single, solitary; Gr. fem. n. spora a seed and in biology a spore; N.L. fem. n. Micromonospora small, single‐spored (organism). Well‐developed, branched, substrate mycelium (0.2–0.6 µm diameter). Nonmotile spores are borne singly, sessile, or terminally on short sporophores. Sporophore development is monopodial or in some cases sympodial. Spores are spherical to oval in shape (0.7–1.5 µm) and in most species have blunt spiny projections. The spores are often carried in branched clusters on short hyphae of the substrate mycelium. Aerial mycelium is usually absent, but some cultures develop sterile short aerial hyphae. Gram‐stain‐positive, mesophilic, non‐acid‐fast. Aerobic to microaerophilic. Chemo‐organotrophic. Sensitive to pH below 5.0. Growth usually occurs between 20 and 40°C, but not above 50°C. Cell wall contains meso ‐diaminopimelic acid and/or 3‐OH‐diaminopimelic acid. Arabinose and xylose are the characteristic sugars present in whole‐organism hydrolysates of most species, but variable amounts of galactose, glucose, mannose, and rhamnose can also be found depending on the species. The major phospholipids are phosphatidylethanolamine, phosphatidylinositol, and phosphatidylinositol mannosides. Saturated and unsaturated fatty acids are present, mostly C 15:0 iso, C 17:0 iso, C 15:0 anteiso, C 17:0 anteiso, C 17:0 10‐methyl, and C 17:0 10‐methyl. Mycolic acids are absent. Major menaquinones are MK‐9(H 4 ), MK‐9(H 6 ), MK‐10(H 4 ), MK‐10(H 6 ), or MK‐12(H 6 ). Isolated from soil, plant materials, freshwater, and marine environments. DNA G + C content ( mol %): 68–75 ( T m , HPLC). Type species : Micromonospora chalcea (Foulerton 1905) Ørskov 1923, 156 AL (“ Streptothrix chalcea ” Foulerton 1905, 1199). Taxonomic and Nomenclature Notes According to the List of Prokaryotic names with Standing in Nomenclature (LPSN), the taxonomic status of the genus Micromonospora is: correct name (last update, February 2025) * . LPSN classification: Bacteria / Bacillati / Actinomycetota / Actinomycetes / Micromonosporales / Micromonosporaceae / Micromonospora The genus Micromonospora can also be recovered in the Genome Taxonomy Database (GTDB) as g__Micromonospora (version v220) ** . GTDB classification: d__Bacteria / p__Actinomycetota / c__Actinomycetes / o__Mycobacteriales / f__Micromonosporaceae / g__Micromonospora * Meier‐Kolthoff et al. ( 2022 ). Nucleic Acids Res , 50 , D801 – D807 ; DOI: 10.1093/nar/gkab902 **