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The properties of 17 strains of a nocardioform actinomycete isolated from soil are described. The hyphae of the primary mycelium of this organism fragment into irregular to rod-to coccus-like elements. The hyphae of the aerial mycelium fragment into rod-to coccus-like elements with smooth surfaces. These elements give rise to new mycelia. The organism is a gram-positive, non-acid-fast, aerobic, mesophile, and it has a cell wall composition of type I (u-diaminopimelic acid, alanine, glutamic acid, glycine). The deoxyribonucleic acid base composition is 66.5 mol% G+C. The actinomycete is susceptible to phages of a taxon-specific set. Polyvalent Nocardia and Streptomyces phages are not propagated in the nocardioform organism, which is here regarded as belonging to a new genus, Nocardioides, the type species of which is N . albus. The type strain o f N . albus is IMET 7807 (Culture Collection of the Zentralinstitut fur Microbiologie und experimentelle Therapie, Jena). It has been deposited in the American Type Culture Collection under the number 27980. The new genus is placed in the family Streptomycetaceae.In a paper presented at a symposium on Noeardia held during the 10th International Association of Microbiological Societies Congress at Mexico City in 1970, Prauser introduced the generic name Nocardioides, with type species N . albus, for an organism which, although widely distributed in soil, could not be identified with any other organism known at the time. The main characters were reported, and cultures of the organism were subsequently sent to a number of specialists for study with the hope that a suitable taxonomic niche could be found for this nocardioform actinomycete. Lechevalier et al. (6) included Nocardioides in their key to the genera of the actinomycetes, and subsequently Prauser received requests to effect the valid publication of names for the genus and its type species, Nocardioides and N . albus not having been previously validly published. It is the intent of this paper to satisfy these requests. Two Arthrobacter strains were also studied: Arthrobacter simplex NCIB 8929 and a strain of this species received under the name Arthrobacter globiformis from the Science Service, Bacteriology Division, Ottawa, Canada (its number in our collection is IMET SG 1020).Phages. The phages used were those isolated by Prauser and Falta (20); Streptomyces phages S5, S6, S7, and S8, phages X5 and X6, Nocardia phages N6, N7, N8, and N9, Oerskoviu phage 0 4 , Promicromonosporu phage P3, and Micromonosporu phages Mm3 and Mm4, all isolated from soil by the author (19), were also included in this study.Media. Cultures of the strains studied were isolated from soil by use of the agar double-layer method, in which dilutions of soil suspensions are mixed in the melted agar used for the upper layer. The isolation media were those commonly used, such as inorganic salts-starch agar (3) and arginineglycerol-salt agar (2). Another medium used was one found suitable for the isolation of many actinomycetes, namely: oatmeal, 3....

Actinomycete genera which contain LL-diaminopimelic acid (LL-A,pm) in their peptidoglycan fall in five phylogenetic lineages, as revealed by 16s ribosomal DNA (rDNA) sequence analyses. These are (i) the streptomycetes (39), (ii) the genus Terrabacter (5), (iii) the genus Sporichthya (30), (iv) the genera Nocardioides and Aeromicrobium (4, 5, 8, 21, 43), and (v) the genera Propionifera (49), Luteococcus (42), and Microlunatus (24). These genera are distinguished from each other and from other actinomycete genera mainly by chemotaxonomic characteristics and by their 16s rDNA sequences. From antarctic sandstone a single ~~-A,pm-containing strain was isolated, and its 16s rDNA was analyzed. On the basis of morphological, physiological, and 16s rDNA analyses, we concluded that this strain, strain AA-1042T (T = type strain), belongs to a new genus and species, for which the name Friedmanniella antarctica is proposed. MATERIALS AND METHODSBacterial strains. Strain AA-1042T was isolated from a sandstone sample containing a cryptoendolithic microbial community collected by one of us (P.H.) at 1,600 m above ocean level from Linnaeus Terrace, McMurdo Dry Valleys, Asgard Range, Transantarctic Mountains, Antarctica (15). The sandstone boulder was flat, had an area of approximately 2 m2, and had at the sampling side (east side) a pH of 4.8. The stone was quite brittle, and some loosened material was directly sprinkled onto the surfaces of PYGV (41) (pH 6.9) agar plates. The plates were incubated for 5 months at 9°C in dim light. Individual colonies around sand grains were picked and streaked onto the same medium for purification. Resulting single and pure colonies were subcultured after 5 months on PYGV agar slants at 4 to 6°C. Strain AA-1042T has been deposited in the IFAM Culture Collection (Institut fur Allgemeine Mikrobiologie, Gel, Germany). The strains used for comparison were the following: Cultural conditions. The biomass used for all chemotaxonomic studies of strain AA-1042T was produced on R-agar slant cultures at 22°C and was harvested after 2 to 3 weeks. Sponchrhya polymorpha was cultivated on nutrient agar at 28°C for 3 weeks. The other organisms were cultivated at 28°C for between 24 and 48 h in 100-ml flasks containing 20 ml of R medium by using a horizontal shaker at 220 rpm. For menaquinone studies organic medium 79 was used. The cell mass used for analyses of cell walls, mycolic acids, and phospholipids and for DNA extraction was obtained in R medium. Fatty acid analyses were performed with cells grown in TSB medium.The following temperatures were used to study growth, morphology, and pigmentation: 6, 9, 18, 22, 25, 28, and 37°C. The source of light for strain AA-1042T was daylight near a window without direct exposure to sun.Staining procedures. Gram staining and acid-fast staining were done as described previously (18).Morphological studies. Cell morphology and aggregate morphology were determined by phase-contrast microscopy (oil immersion objective; magnification, X100) of material obtained from surface ...

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