Mary P. Lechevalier

CHEMICAL COMPOSITION AS A CRITERION IN THE CLASSIFICATION OF AEROBIC ACTINOMYCETES

ABSTRACT The information concerning the main components found in cell wall preparations and whole-cell hydrolysates of some 600 strains of aerobic actinomy-cetes is reviewed. The results show that whole-cell sugar patterns can usually be used to predict cell wall composition and that the combination of both criteria permit separation of aerobic actinomycetes into 10 taxonomically useful groups.

Chemotaxonomy of aerobic Actinomycetes: Phospholipid composition

Abstract A survey of the phospholipid composition of 97 strains representing 20 genera of the Actinomycetales showed that five groups could be distinguished on the basis of the presence or absence of certain nitrogenous phospholipids. Phospholipid type PI (no nitrogenous phospholipids) is characteristic of the genera Actinomadura (madurae, pelletieri).Corynebacterium, Microtetraspora and Nocardioides. Actinomycetes of Type PII contain only one nitrogenous phospholipid, phosphatidyl ethanolamine. These include members of the genera Actinoplanes, Chainia, Dactylosporangium, Microellobosporia, Micromonospora, Micropolyspora (brevicatena), Mycobacterium, Nocardia (all species examined but autotrophica), Streptomyces and Streptoverticillium. Phospholipid pattern type PIII (characteristic phospholipid, phosphatidyl choline) was found in Actinomadura (dassonvillei). Micropolyspora (faeni), Nocardia (autotrophica), and Pseudonocardia. Actinomycetes having a type P IV pattern contain an unknown, previously undescribed phospholipid containing glucosamine (GluNU) which was found to be characteristic of members of the genera Intrasporangium, Microbispora and Streptosporangium. Actinomycetes of type PV contain phosphatidyl glycerol in addition to GluNU and include members of the genera Promicromonospora and Oerskovia. Other phospholipids found variably in all groups included phosphatidyl inositol, phosphatidyl inositol mannosides, phosphatidyl methylethanolamine, acyl phosphatidyl glycerol (APG) and diphosphatidyl glycerol (DPG). The fatty acids present in DPG (or APG when DPG was absent) may be species-specific. The chemical heterogeneity of the genera Actinomadura, Corynebacterium, Micropolyspora and Nocardia is discussed.

Nocardia amarae sp. nov., an Actinomycete Common in Foaming Activated Sludge

One hundred and seven strains of nocardiae have been isolated from samples of activated sludge or from foam forming on activated sludge coming from 10 sewage-treatment plants in five states. Thirty-five of these strains belong to a previously undescribed species containing a novel type of nocardomycolic acid whose α branch is mono-unsaturated. The name proposed for this new species is Nocardia amarae. The type strain is IMRU W3960 (= ATCC 27808).

Evidence for a Close Phylogenetic Relationship Between Members of the Genera Frankia, Geodermatophilus, and “Blastococcus” and Emdendation of the Family Frankiaceae

Summary The phylogenetic position of two Frankia strains, isolated from two different host plants, was analyzed by reverse transcriptase sequencing and/or oligonucleotide cataloguing of their 16S ribosomal RNA. The two strains are highly related, showing a distinct relationship to Geodermatophilus obscurus and a strain of “Blastococcus” . These organisms constitute a main subline of descent within the phylogenetic radiation of the order Actinomycetales . In contrast to the present classification the genera Geodermatophilus and Dermatophilus cannot be considered members of the same family. Geodermatophilus is transferred into the family Frankiaceae for which an emended description is given.

Taxonomy of the Genus Frankia (Actinomycetales)

Members of the genus Frankia have been classified in the order Actinomycetales on the basis of morphology, cell chemistry, and 16S rRNA sequences and catalogs. This genus, which is presently defined by morphology, cell chemistry, the ability to fix nitrogen, and infectivity for and ability to enter into symbiotic relationships with certain plant hosts, may be heterogeneous. Frankia species groups have been difficult to delineate by classical phenotypic methods. The recent use of DNA-DNA pairing and low-frequency restriction fragment analysis, as well as probes composed of certain sequences from the nif (nitrogen fixation) genes or the variable regions of 16S rRNA, has contributed to substantial progress in developing species concepts. In this review I trace the taxonomic history of the genus and outline some of the problems to be resolved in the future.

New Genus of the Actinomycetales: Actinosynnema gen. nov.

An aerobic species of a new genus, Actinosynnema, is described under the name A. mirum sp. nov. The type strain of A. mirum is strain Hasegawa 101 (= IMRU 3971). The new genus is characterized by the formation of synnemata originating from the substrate mycelium. At the tip of the synnemata, chains of zoospores are produced.

Description of a New Species, Oerskovia xanthineolytica, and Emendation of Oerskovia Prauser et al.

A new species belonging to the genus Oerskovia Prauser et al. of the order Actionmycetales is described under the name O. xanthineolytica. It differs from O. turbata mainly in its ability to hydrolyze xanthine and hypoxanthine, in certain carbohydrate reactions, in the production of a phosphatase, and in its ability to grow at 42 C on Trypticase-soy agar. The type strain of this species is IMRU 3959 (LL G62) (=ATCC 27402). The description of the genus Oerskovia is emended to take into account the fact that members of this genus can grow anaerobically on Trypticase-soy medium with the production of catalase-negative biomasses.

The taxonomy of the genus Frankia

A discussion covering the problems of Frankia taxonomy was held at the “Frankia Workshop” in Wageningen, September 4–6, 1983. It was agreed that the genus Frankia can be satisfactorily defined, but that solid criteria for species determination are not now available and that use of specific names should be avoided for the present.

Physiology and chemical diversity of Frankia spp. isolated from nodules of Comptonia peregrina (L.) Coult. and Ceanothus americanus L.

Two Frankia spp., isolated from the nodules of the plant host Comptonia peregrina, were found to fall into two previously described physiological groups (A and B). Of five frankia isolates from Ceanothus americanus plants of the same provenance, three belonged to physiological group A and two to a novel group whose final disposition remains to be decided. The diversity in whole cell sugar chemistry, morphology and other growth characteristics of these strains is discussed.

Thermoactinomyces candidus, a New Species of Thermophilic Actinomycetes

Thermoactinomyces candidus, a new species isolated from home environments and other sources, is reported. T. candidus differs from T. vulgaris in that the former species hydrolyzes esculin, splits arbutin, and does not attack tyrosine, hypoxanthine, or starch, whereas the latter does. T. candidus differs from T. sacchari by producing fast-growing colonies, abundant aerial mycelia, and hemolysis in blood agar, by decomposing esculin and arbutin, and by failing to hydrolyze starch. The type strain of T. candidus is T-106 (= ATCC 27868).