Thermus, Brock & Freeze, 1969

Brock, Thomas D. & Freeze, Hudson, 1969, Thermus aquaticus gen. n. and sp. n., a Nonsporulating Extreme Thermophile, Journal of Bacteriology 98 (1), pp. 289-297 : 295

Thermus gen. n.

Morphology: Rods and filaments, 0.5 to 0.8,um in diameter. Rods 5 to 10 Am in length, filaments of variable length from 20 to greater than 200,um. Rods occurring singly or in aggregates, the latter either side-to-side or end-to-end (rosette-like). Large spheres 10 to 20 Am in diameter usually formed in old cultures. Gram-negative. Flagella and endospores absent. Gliding motility has not been observed.

DNA base composition: 65.4 to 67.4% GC.

Colony characteristics: Compact slowly spreading colonies. Yellow to bright orange on 0.1% tryptone plus 0.1% yeast extract plus mineral salts-agar.

Liquid culture: Yellow surface pellicle often formed in unshaken liquid cultures.

Temperature relations: Optimum, 70 to 72 C, maximum 79 C, minimum around 40 C.

Nutrition: No growth factor requirements (one strain tested). Nitrogen sources, amino acids and NH4+. Carbon sources, sugars, and organic acids. Grows best in complex media such as 0.1 to 0.3% tryptone plus yeast extract.

Relation to oxygen: Obligately aerobic.

Relation to pH: Optimum 7.5 to 7.8. No growth below pH 6 or above 9.5.

Inhibitor sensitivity: Inhibited by 10 Mg or less of streptomycin, penicillin, novobiocin, actinomycin D, or chloramphenicol per ml.

Inhibited by 100 ug or less of cycloserine, tetracycline, and sodium lauryl sulfate per ml. Inhibited by 500 Mug or less of sodium azide per ml. Inhibited by 2% NaCl. Inhibited by 200 ug or less of oxgall per ml.

Source: Hot springs, hot tap water.

The name given to this organism is derived from the Greek noun, thermos, meaning hot. One species.