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Chapter 1: INTRODUCTION
1.1 -
Temperature as a regulatory factor
Temperature is a fundamental factor in the regulation of metabolism in living
organisms. Its influence can be seen in all cellular processes directly in terms of growth
rates, enzyme activity and cell composition (Herbert, 1986), and in its effect on aqueous
systems (solute concentrations, diffusion rates and osmotic effects) (Oppenheimer, 1970;
Herbert, 1986; Russell, 1990). Organisms which survive, or even thrive, at extremes of
temperature are known as extremophiles (Huber & Stetter, 1998; Russell and Hamamoto,
1998; Stetter, 1999). The major aim of the current investigation was to investigate the
adaptations employed by organisms that enable them to proliferate and function in the
extremely low temperatures of the Antarctic environment, with the goal of isolating novel
anti-freeze proteins from a bacterial source and delineating the environmental parameters
which have promoted such activity. Further to this, the study investigated the taxonomy,
phylogeny and ecology of bacterial assemblages in Antarctic lacustrine ecosystems.
1.2 -
Cold environments
The large global extent of cold environments (