Goodfellow, Michael

Abstract A.my.co.la.top'sis. N.L. fem. n. Amycolata genus belonging to the order Actinomycetales ; Gr. fem. n. opsis aspect, appearance; N.L. fem. n. Amycolatopsis that which appears similar to Amycolata . Aerobic to facultatively anaerobic , Gram‐stain‐positive , non‐acid‐fast , nonmotile , catalase‐positive actinomycetes that form branching substrate hyphae which fragment into squarish and rod‐shaped elements . When formed , aerial hyphae may be sterile or differentiate into chains of smooth‐walled , squarish to ellipsoidal spore‐like structures . Chemo‐organotrophic to facultatively autotrophic. Grows on a broad range of organic and synthetic media. Mesophilic or thermophilic. Whole‐organism hydrolysates are rich in meso ‐2 , 6‐diaminopimelic acid , arabinose , and galactose . The peptidoglycan is of the A1γ type. Muramic acid moieties are N ‐acetylated. The diagnostic phospholipid is phosphatidylethanolamine ( with or without phosphatidylmethylethanolamine ) or phosphatidylmethylethanolamine with variable occurrence of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, and phosphatidylinositol mannosides; contains complex mixtures of saturated and branched chain fatty acids . Does not contain mycolic acids. The phylogenetic position of Amycolatopsis , as determined by 16S rRNA gene sequence analysis, is in the family Pseudonocardiaceae . Common in arid soils but has also been isolated from activated sludge, equine placentas, and from clinical and plant material. DNA G + C content ( mol %): 66–75 ( T m ; HPLC). Type species : Amycolatopsis orientalis (Pittenger and Brigham 1956) Lechevalier, Prauser, Labeda and Ruan 1986, 35 VP . Taxonomic and Nomenclature Notes According to the List of Prokaryotic names with Standing in Nomenclature (LPSN), the taxonomic status of the genus Amycolatopsis is: correct name (last update, February 2025) * . LPSN classification: Bacteria / Bacillati / Actinomycetota / Actinomycetes / Pseudonocardiales / Pseudonocardiaceae / Amycolatopsis The genus Amycolatopsis can also be recovered in the Genome Taxonomy Database (GTDB) as g__Amycolatopsis (version v220) ** . GTDB classification: d__Bacteria / p__Actinomycetota / c__Actinomycetes / o__Mycobacteriales / f__Pseudonocardiaceae / g__Amycolatopsis * Meier‐Kolthoff et al. ( 2022 ). Nucleic Acids Res , 50 , D801 – D807 ; DOI: 10.1093/nar/gkab902 ** Parks et al. ( 2022 ). Nucleic Acids Res , 50 , D785 – D794 ; DOI: 10.1093/nar/gkab776

The taxonomic positions of three thermophilic actinomycetes isolated from arid soil samples were established by using a polyphasic approach. The organisms had chemical and morphological features that were consistent with their classification in the genus Amycolatopsis . 16S rRNA gene sequence data supported the classification of the isolates in the genus Amycolatopsis and showed that they formed distinct branches in the Amycolatopsis methanolica subclade. DNA–DNA relatedness studies between the isolates and their phylogenetic neighbours showed that they belonged to distinct genomic species. The three isolates were readily distinguished from one another and from the type strains of species classified in the A. methanolica subclade based on a combination of phenotypic properties and by genomic fingerprinting. Consequently, it is proposed that the three isolates be classified in the genus Amycolatopsis as representatives of Amycolatopsis granulosa sp. nov. (type strain GY307T = NCIMB 14709T = NRRL B-24844T), Amycolatopsis ruanii sp. nov. (type strain NMG112T = NCIMB 14711T = NRRL B-24848T) and Amycolatopsis thermalba sp. nov. (type strain SF45T = NCIMB 14705T = NRRL B-24845T).

A thermotolerant, Gram-stain-positive, aerobic, sporangium-forming actinomycete, strain RA45T, was isolated from a desert region in Xinjiang Uigur Autonomous Region, north-western China. Comparative analysis of the 16S rRNA gene sequence and phenotypic characterization revealed that strain RA45Tbelonged phylogenetically to the familyPseudonocardiaceaeof the suborderPseudonocardineae. Strain RA45Tshowed more than 5 % 16S rRNA gene sequence divergence from recognized species of genera in the familyPseudonocardiaceae, forming a distinct lineage within the evolutionary radiation occupied by the generaAmycolatopsis,Prauserella,Thermocrispum,Saccharomonospora,SaccharopolysporaandSciscionella, but distinct from each of them. The affiliation to the family was supported by the presence of suborder- and family-specific 16S rRNA signature nucleotides, a DNA G+C content of 69.9 mol%, the presence ofmeso-diaminopimelic acid, ribose, arabinose, glucose and galactose, which are characteristic components of cell-wall chemotype IV of actinomycetes, the presence of menaquinone MK-9(H4) as the major respiratory lipoquinone, a lack of mycolic acids and the presence of anN-acetylated type of muramic acid. However, strain RA45Tdiffered from known genera of the family in its polar lipid composition: the major phospholipids were phosphatidylethanolamine, phosphatidylinositol mannosides, phosphatidylmethylethanolamine, diphosphatidylglycerol, phospholipids of unknown structure and phospholipids of unknown structure containing glucosamine (phospholipid type IV). Based on its morphological, chemotaxonomic and phylogenetic characteristics, strain RA45Tis considered to represent a novel species of a new genus in the familyPseudonocardiaceae, for which the nameYuhushiella desertigen. nov., sp. nov. is proposed. The type strain ofYuhushiella desertiis RA45T(=CGMCC 4.5579T=JCM 16584T).

The taxonomic position of a group of mesophilic actinomycetes isolated from arid Australian soils was determined using a polyphasic approach. The organisms shared chemical and morphological markers typical of members of the genusAmycolatopsis. They had identical 16S rRNA gene sequences and formed a distinct phyletic line in theAmycolatopsis mediterraneiclade, being most closely related toA. mediterranei. In addition, they shared a range of phenotypic properties that distinguished them from representatives of all of the species classified in this clade. The combined genotypic and phenotypic data indicate that the strains merit species status within the genusAmycolatopsis. The name proposed for the novel species isAmycolatopsis australiensissp. nov.; the type strain is GY048T(=DSM 44671T=NCIMB 14142T).