Isolation and Preliminary Taxonomic Studies of Thermus Strains Isolated from Yellowstone National Park, USA

Abstract

Forty-eight strains of Thermus isolated from hot springs in Yellowstone National Park, Wyoming, USA, and eight reference strains were subjected to a numerical taxonomic analysis using Gower's coefficient (SG) with single and average linkage clustering. Two major groups were distinguished, which could be differentiated by colony morphology, ability to reduce nitrate and proteolytic activity. Cluster 1 contained Thermus aquaticus YT-1, the type strain of the species, and cluster 2 contained authentic strains of 'T.flavus' and 'T. therrnophilus'. T. ruber was recovered as a single member cluster. The mol % G + C of DNA from representative strains from each cluster was 64.4 to 66.8 for cluster 1, 62.2 to 67.1 for cluster 2 and 62.5 for T. ruber.

Thermus oshimai sp. nov., Isolated from Hot Springs in Portugal, Iceland, and the Azores, and Comment on the Concept of a Limited Geographical Distribution of Thermus Species

“…Thermus thermophilus strains are known to occur in widely separated areas, including Icelandic terrestrial (47) and marine hot springs (23) and Sao Miguel in the Azores. The 16s rDNA sequence of ZHGIAl, which was isolated in Iceland (18), indicates that this strain belongs to the species Thermus brockianus, which was found (53) among strains obtained from Yellowstone National Park in the United States (27). Similarly, the sequence of the 16s rDNA gene of isolate NMX2A1 from New Mexico (19) indicates that this organism is similar to the Vizela strains from Portugal and Sao Miguel Island in the Azores, which themselves belong to a species whose strains have been isolated from sources in Britain, the United States, and Iceland.…”

“…The Gram reaction is negative, and the cell wall has an outer layer that balloons out from the inner peptidoglycan at regular intervals (3, 49). Thermus strains have been isolated from hot springs and other thermal environments in the United States (2, 4, 5, 27,35,44,53), Iceland (1, 7, 18, 21-23, 32, 42), Belgium (€9, Britain (31), Portugal (26,39,47,48), the Czech Republic (34), Germany (15), the former USSR (24,25), Japan (28,29,37,45,46), New Zealand (16, 17), Thailand (20), and Kenya (51). Thermus isolates are usually yellow pigmented because they contain carotenoids, but colorless strains have been isolated from sources sheltered from light (2, 22,31,35,39,44).…”

Characterization of halotolerant Thermus isolates from shallow marine hot springs on S. Miguel, Azores

“…These organisms constitute one of the major aerobic heterotrophic populations at sites with pH >5 and temperatures between 55 "C and 85 "C ( Kristjansson & Aldredsson, 1983;Munster et al, 1985). Several strains have also been described from shallow marine hot springs venting fresh water in Iceland (Kristjansson et al, 1986) and one strain was isolated from a site on a beach on Fiji (Hudson et al, 1989).…”

“…The high-temperature strains of the genus Thermus, with optimum growth temperatures between 70 "C and 75 "C, have a worldwide distribution in neutral to alkaline terrestrial hot springs (Munster et al, 1986;Hudson et al, 1989, Santos et al, 1989 and artificial environments (Pask-Hughes & Williams, 1975 ;Stramer & Starzyk, 1981). The small number of marine isolates examined are markedly more halotolerant than the vast majority of high-temperature Thermus, but share several phenotypic characteristics with the terrestrial organisms.…”

Transfer of Thermus ruber (Loginova et al. 1984), Thermus silvanus (Tenreiro et al. 1995), and Thermus chliarophilus (Tenreiro et al. 1995) to Meiothermus gen. nov. as Meiothermus ruber comb. nov., Meiothermus silvanus comb. nov., and Meiothermus chliarophilus comb. nov., Respectively, and Emendation of the Genus Thermus

“…Thermus aquaticus (3), Thermus filiformis (lo), Thermus scotoductus (ll), Themus thermophilus (14,18,28), and Thermus brockianus (15,28) form yellow or nonpigmented colonies and have optimum growth temperatures of about 70°C. All of the strains assigned to these species except the strains assigned to T. thermophilus have maximum growth temperatures below 80°C (13,14).…”