Population distribution of aerobic extremely thermophilic microorganisms in an icelandic natural hot spring

Isolation of strains of Thermus aquaticus from the Australian Artesian Basin and a simple and rapid procedure for the preparation of their plasmids

“…Also of interest is that the plasmid profiles of T. aquaticus isolates from the runoff channel of bore number 4164 did not possess the same plasmid profile 77 as the isolates obtained from the source waters of the bore (Table 1). This type of plasmid variation may be similar to the phenotypic variation observed amongst T. aquaticus strains that had been isolated from various sites of the runoff channel of an Icelandic hot spring [14]. It has been suggested that the extraordinary degree of spontaneous phenotypic variability in thermophiles, including T. aquaticus, may be a genetic property of organisms that are exposed to an extreme environmental stress not experienced by mesophilic organisms.…”

“…Therefore the upper and lower temperature niche recorded in the Australian Artesian waters and their runoff channels for this bacterium is limited due to the effects of temperature rather than pH. In general, however, the temperature range is similar to that observed for the isolates obtained from the volcanic hot waters of Iceland [13,14]. There appeared to be no correlation between the plasmid size and/or numbers amongst the four of the six T. aquaticus strains isolated from the water samples collected directly from bores.…”

A Numerical Classification of Some Thermus Isolates

“…are widely distributed in natural, thermally heated waters in the USA (Brock & Freeze, 1969), Iceland (Pask-Hughes & Williams, 1977;Cometta et al, 19826;Kristjansson & Alfredsson, 1983), Japan (Saiki et al, 1972), the USSR (Egorova & Loginova, 1974) and New Zealand (Patel, 1984). They also occur in man-made hot-water environments, for example hot tap-water (Pask-Hughes & Williams, 1979, laundry and domestic hot-water tanks (Brock & Boylen, 1973), nuclear power plant cooling systems and water discharged from steel mills (Stramer & Starzyk, 1981).…”

Isolation and characterisation of plasmids from a wild-type strain of the extremely thermophilic eubacterium Thermus aquaticus

“…To examine whether all plasmids were present in a single cell, cultures were plated out onto solid media containing 3% agar and incubated at 72°C for 1-2 days. Based on previous work with Thermus isolates in continuous culture [13], it was suggested that there is a high degree of genetic instability within members of this genus. The results confirm that there is phenotypic variability, but they neither confirm nor refute the hypothesis of genetic instability.…”