Extremophilic microorganisms are called extremophiles and live in environments considered hostile to most forms of life. Scientists have only discovered life in these extreme environments in the last few decades. Extremophiles are not able to be grown or cultivated in a laboratory using common techniques, so scientists didn’t even know they existed for many years.
Most of the bacteria that live in Antarctica can’t be cultivated using the methods that we know about. One of the reasons is that they live in quite complex communities – so one bacterium relies on its buddies to be able to survive.Dr Adele Williamson
In order to survive, extremophiles have become specialised for different extreme environments. Species have adapted and evolved to survive in conditions such as extreme temperatures or pH, high salinity, UV bombardment, lack of oxygen and/or low nutrient levels.
Extremophile microorganisms have adapted to these extreme conditions. They utilise unique biochemical processes to make effective use of the resources available and protect them from damage caused by the environment. These processes involve many unique metabolic pathways and are controlled by unique enzymes that are not found in other living things.
Dr Adele Williamson from The University of Waikato is looking at extremophiles from a variety of sources including Antarctic soil samples and the upper layers of the ocean. Her research aims to source new and novel enzymes that could have multiple applications, for example in new medicines and therapies and as laboratory tools.
Enzymes have many uses in industry, medicine, our homes and a range of other things. Many enzymes found in extremophiles can function outside the range of the ‘normal’ conditions most enzymes require. Some are involved in biochemical reactions that produce potentially useful products, in important biochemical processes or in the efficient breakdown of particular substrates. They are very interesting to molecular biologists as they offer a potential source of new biotechnology tools, processes and products.
Many extremophiles have extremely effective DNA repair and replication mechanisms by using unique enzyme-controlled biochemistry to counter the harshness of their environment. Enzymes such as restriction enzymes involved in DNA repair and replication are particularly useful for biotechnology. Understanding how these mechanisms operate in extremophiles may enable scientists to expand the potential range of situations and uses for enzyme-based biotechnology tools.
As extremophiles are unable to be propagated in the laboratory, in order to produce quantities of an enzyme of interest, scientists must first sequence the DNA and isolate the gene(s) responsible for the enzyme’s production. Then, using techniques such as PCR, DNA cloning and recombinant DNA technology, scientists can produce and modify these enzymes for the desired purpose(s).
The bacterium E. coli is often used in these processes because it is easily grown and well understood. DNA can be inserted into plasmids of E. coli, which can then be utilised in a variety of ways – including to make large quantities of a useful enzyme.
Nature of science
As our understanding of extremophiles and their unique biochemistry increases, so do the potential applications of this knowledge in biotechnology.
In July 2022 RNZ’s Our Changing World programme featured Dr Adele Williamson and her work on the clues about DNA repair systems from bacteria found in Antarctica.