Secrets Of Extremophile Bacteria Decoded With Neutrons

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Microbes like bacteria or virus mostly define the most basic life-form on this planet, if we can understand their behaviour a lot of our survival and well-being problems can be solved. Microorganisms like bacteria or virus have an unparalleled ability to adjust with extreme temperatures and climates especially in niches that are highly acidic, basic, or cold or hot. Or salty. The best example is that of organisms surviving in the depths of high pressure and salty environment. Such conditions are fatal for higher level organisms. The organisms capable of surviving in such harsh conditions are known as extremophiles.


Figure 1: Extremophile

Bacteria extracted from salt marshes represent one such class that includes scores of species and subspecies. These bacteria are known for having some very strong biotechnological potential. One such organism is Halomonas titanicae that was derived from the remains of sunken RMS Titanic is being estimated that this rust producing bacteria will decompose the complete ship by 2030. This means similar dangers exist for other deep sea located man-made objects like the oil rigs. Other side of this story is that the same bacteria can be used in waste management and faster decomposition of waste materials.

A number of experiments and tests were conducted on these bacteria by one of the leading neutron research centre of the world - Institut Laue-Langevin (ILL) in association with the Max Planck Institute of Biochemistry (MPIB), Institut de Biologie Structurale (IBS) and Bitop Biotechnology Company to observe the reaction between water, protein, and ectoine. Ectoine is a natural compound capable of protecting human body by behaving as an osmolyte - a special kind of molecule known for playing important role in cell volume maintenance and fluid balance. Thus, it helps the organisms survive under extreme environmental pressures. It is also a very compatible solute for the fact that its presence in internal most end of cell never affects the metabolism or biochemistry of cells.

Halomonas is capable of generating ectoine across a wide range of salt concentrations. The substance itself has found an indirect balancing effect over membranes and proteins along with an inhibitory effect over inflammation in mammals. This has given it quite a significance in cosmetic industry. The neutrons were used in a combination with some highly-advanced deuterium labelling methods to show how ectoine behaves after separating from liquid molecules, on membrane and protein molecule surfaces.

Dr. Joe Zaccal, the CNRS Emeritus Scientist at ILL explains, “It is well-known that the search for Life on Mars and elsewhere in the universe, is guided by a search for liquid water. This is because liquid water is essential for all Life. Its remarkable properties are based on dynamic H-bond networks that play vital roles in macromolecular folding and interactions, which in turn determine their biological functions. The results in this study illustrate how the osmolyte behind the halotolerance response in microorganisms induces compensating effects on water H-bonding that respect these essential biological properties. Neutrons provide the ideal tool for investigating structure and dynamics in water and biological molecules–they have a number of unique advantages, including amongst others their high penetrative power with no radiation damage to the sample and their sensitivity to labelling a structure by replacing hydrogen with its isotope deuterium. Each of the instruments used in the study acted like a 'giant microscope' of different magnification for us to 'see' details from the crucial hydrogen-bond formations at the atomic level to the larger protein and membrane structures. Although much spectroscopic and thermodynamic investigations have been done before on ectoine, we are proud that through the use of neutrons this is the first study that has allowed a direct experimental characterisation of ectoine-water-protein and ectoine-water-membrane structures to explain the mode of action of this very interesting and useful molecule."