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Spores survive high temperatures: bacteria

Spores of some bacteria may be able to survive high temperatures in part because their unfolded proteins are rotationally immobilized, preventing tangling during dormancy.

BIOMIMICRY TAXONOMY
Summary
"To survive long periods without nutrients or other adverse conditions, certain types of bacteria have developed the ability to form spores, where the cell's DNA and necessary enzymes are packed into a capsule surrounded by multiple protective barriers. In this form the bacteria can survive for hundreds, perhaps millions, of years in a dormant state and, what's more, endure drought, extreme temperatures, radiation, and toxins that would quickly knock out unprotected bacteria

"'What we have discovered is that the water in the spore is nearly as fluid as in regular bacteria, while the enzymes are largely immobile. We therefore think that spores' heat resistance and ability to shut down their cell machinery can be ascribed to the fact that certain critical enzymes do not function in the low water content in the spore core. But much more work is needed to figure out the details of the mechanism,' explains Bertil Halle

"Another important observation crucial to understanding why spores can survive temperatures up to 150 degrees centigrade is that the proteins in the spore do not move freely, as in a water solution.

"'When the temperature rises, protein molecules unfold into long chains. Since the molecules in the spore core are immobilized, they don't get tangled up with each other, as they would in ordinary cells. When the temperature goes down, they fold up again, and no damage has been done to the cell,' explains Erik Sunde." (Viegas 2009)

Excerpt
"The bacterial spore, the hardiest known life form, can survive in a metabolically dormant state for many years and can withstand high temperatures, radiation, and toxic chemicals. The molecular basis of spore dormancy and resistance is not understood, but the physical state of water in the different spore compartments is thought to play a key roleSpore dormancy therefore cannot be explained by glass-like quenching of molecular diffusion but may be linked to dehydration-induced conformational changes in key enzymes. The data demonstrate that most spore proteins are rotationally immobilized, which may contribute to heat resistance by preventing heat-denatured proteins from aggregating irreversiblyThe quantitative results reported here on water mobility and transport provide important clues about the mechanism of spore dormancy and resistance, with relevance to food preservation, disease prevention, and astrobiology." (Sunde et al. 2009: 19334)
About the inspiring organism
Bacillus
Bacillus

Learn more at EOL.org
Organism/taxonomy data provided by:
Species 2000 & ITIS Catalogue of Life: 2008 Annual Checklist


Bioinspired products and application ideas

Application Ideas: Protecting organic materials (foods, medicines) from high temperatures.

Industrial Sector(s) interested in this strategy: Food, medicine, packaging

Experts
Halle Research Group
Bertil Halle
Department of Biophysical Chemistry, Lund University
References
Viegas J. 2009. World's hardiest life form explained. Discovery News [Internet],
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Sunde EP; Setlow P; Hederstedt L; Halle B. 2009. The physical state of water in bacterial spores. PNAS. 106(46): 19334-19339.
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