Thermophilic Actinomycetes Research Articles

STUDIES ON PEAT AND PEAT MICROORGANISMS. II. OCCURRENCE OF THERMOPHILIC FUNGI IN PEAT.

Thermophilic Actinomycetes were isolated from various peat samples and examined in detail. Most of them were classified as Thermoactinomyces vulgaris, a species which frequently occurs in very different habitats.

Farmer's Lung: Thermophilic Actinomycetes as a Source of "Farmer's Lung Hay" Antigen

Farmer's Lung: Thermophilic Actinomycetes as a Source of "Farmer's Lung Hay" Antigen

THERMOPHILIC AND MESOPHILIC ACTINOMYCETES IN MOULDY HAY.

SUMMARY: Actinomycetes isolated at 40° and/or 60° from mouldy hay included: Micromonospora vulgaris Waksman et al., Thermopolyspora polyspora Hens., T. glauca sp.nov., Streptomyces thermoviolaceus Hens., S. fradiae (Waksman et Curtis) Waksman et Henrici, S. griseoflavus (Krainsky) Waksman et Henrici, S. olivaceus (Waksman) Waksman et Curtis, and S. griseus (Krainsky) Waksman et Henrici.

'REFUIN': A NON-CYTOTOXIC CARCINOSTATIC COMPOUND PROLIFERATED BY A THERMOPHILIC ACTINOMYCETE.

‘REFUIN’ is a high-molecular fraction of a fermentation beer produced by a thermophilic actinomycete. The fraction is recovered by precipitation with ammonium sulphate and by fractional ice crystallization. Although the fermentation temperature is 50° C, the active principle is heat-labile, losing all activity after 6 h at room temperature. Electrophoretic analysis reveals a ninhydrin staining positively charged band.

Isolation of thermophilic actinomycetes.

To judge from reports in the literature, thermophilic Actinomycetes have proved difficult to isolate. For isolations from mouldy hay we have developed a convenient method which promises to be useful in other contexts1. The method uses the fact that dry air removes spores of the Streptomycetaceae in preference to bacteria. Instead of suspending the spores in water and plating dilutions in the traditional manner, dry spores are suspended in air and impacted with the Andersen sampler2 directly on surface-dried medium. In our work, samples of hay are shaken in a small wind tunnel and the air drawn into an Andersen sampler loaded with Petri dishes which had been poured the day before with half-strength nutrient agar (agar content made up to 2 per cent) containing 0.5 mgm./ml. actidione to suppress growth of mould. A slit-sampler could be used as an alternative to the Andersen sampler, and instead of using a wind tunnel, hay or other material can be shaken in a box (pre-sterilized with propylene oxide if required) and a few minutes allowed for larger particles to settle before sampling the air.

Studies on the thermophilic actinomycetes. I. Methods of cultivation.

A total of 1,000 isolates of thermophilic actinomycetes representing two genera, Streptomyces and Thermoactinomyces, were studied. Media for cultivation and for physiological studies were designed. Differences between the two genera are noted and taxonomic criteria for the genus Thermoactinomyces are suggested. The importance of the nutritional environment to the thermophilic habit is noted.

A defined medium for the growth of the thermophilic actinomycete Micromonospora vulgaris.

SUMMARY: Biotin and methionine are essential growth factors for the aerobic thermophilic actinomycete Micromonospora vulgaris. Biotin can be partially replaced by Tween 80 (sorbitan mono-oleate). No aerial growth is obtained in the absence of methionine. A chemically defined medium containing mineral salts, phosphate buffer (pH 6·8), soluble starch, a mixture of 18 synthetic amino acids (including methionine) and biotin will support growth of the organism.

The reproductive pattern of Micromonospora vulgaris.

SUMMARY: The thermophilic actinomycete Micromonospora vulgaris resembles known mesophilic members of the genus Micromonospora in reproducing by means of small retractile spores borne singly on lateral branches of the vegetative mycelium. Its distinctive feature is the consistent production of a secondary aerial mycelium under optimal laboratory cultural conditions and in grass composts during the high temperature phase. This aerial mycelium is composed of abundantly branched, hydrophobic filaments which rapidly segment. The cells in these filaments may in turn give rise to similar refractile spherical spores borne singly on very short lateral branches. The reproductive pattern here described is one of the most complex yet known among the actinomycetes. It is thought that the aerial phase of development is intimately associated with the thermophilic nature of the organism.

Temperature/growth relationships of a thermophilic actinomycete, Micromonospora vulgaris.

SUMMARY: The only thermophilic actinomycetes found in composts made from lawn cuttings were members of the genus Micromonospora. The isolates obtained agreed in the main with the description of M. vulgaris (Tsiklinsky) Waksman, Umbreit & Cordon. Three strains have been studied in detail. They are true thermophiles, with an optimum range of growth 45–60°, and appear in abundance at the high-temperature phase of the compost, with a profuse production of aerial mycelium and spores. Spore germination is induced by heat activation, 5 min. at 85° securing growth under suboptimal conditions. Thin suspensions of spores in 1 % sucrose or in very dilute nutrient broth withstand 100° for periods of up to 45 min. Only very dense aqueous or saline suspensions are tolerant of these exposures. Surface growth on cellophan bearing a high density of aerial mycelium and spores withstands dry heating at 100° for 150 min. or at 106° for 5 min.

Aerobic Mesophilic Bacteria in Composts

IN a previous communication1, an account was given of the activity of the thermophilic flora which develops in composts made from grass cuttings (lawn mowings). This thermophilic flora can be seen as a white coating on the cuttings, particularly in the upper layers during the high-temperature phase. From it true and facultative thermophilic bacteria were isolated. Recently, in addition, evidence of the presence of a thermophilic actinomycete has been obtained (cf. Waksman et al.2).