ý.,,: V. ý ýý . - Nottingham eTheses - University of Nottingham

et al., 1994) and the Antarctic SIMCO (Brown & Bowman; 2001). However, it has never
been isolated from Triple Lake, Vestfold Hills, which demonstrates such an extreme
hypersaline and cold environment, and it may therefore be a novel species or strain.
Bowman et al.. (2000) did demonstrate a 16S rRNA clone from the sediments of Deep
Lake (the most hypersaline lake in the Vestfold Hills) which showed a close relationship
with Halomonas subglaciescola. This indicates not only that Halomonas species can exist
in extremely saline and cold environments, but also that Halomonas species have been
isolated from the lakes of the Vestfold Hills, thus increasing the likelihood of the
identification of isolate 213 as a member of the genus Halomonas. The identification of
isolate 213 as Halomonas sp is therefore not unexpected, but complete sequencing of the
16S rRNA gene would be necessary for this identification to be definitive.
5.3.2.10 -
Isolate 466
Isolate 466 is shown using ARDRA analysis to be a distant relative of the ;t
protea grouping this was demonstrated in both enzymatic digestions, but was more
obvious in the Alu I digestion, where the phenetic similarity was -75%. Due to this
assessment it was considered that it is possible that this strain does belong to the gamma
Proteobacteria, however, sequence assessment of the 153bp 16S rRNA gene fragment for
isolate 466 demonstrated a very weak relationship (87.2%) with Bacillus aquamarinus
(AF202056) which is part of the Bacillus / Clostridium group, which has been noted in
Antarctic lakes (Brambilla et al., 2001) and psychrophilic species have been noted in
deep-sea sediments (Rüger et al., 2000), and while it is a marine based species (Yoon et
al., 2001) the sequence similarity is to small to realistically consider it as a possibility.
More conclusively isolate 466 was Gram negative whereas members of the genus
Bacillus are Gram positive, and hence it is extremely unlikely that it could be related to
this genus. It is thus possible that the sequence obtained is the result of PCR
contamination. Hence no definitive identification of isolate 466 can be given at this point:
further work was required to identify this isolate, but as it had a low level of AFP activity
it was considered to be superfluous and so was not pursued further.
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