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Proceedings Paper

The nature of water within bacterial spores: protecting life in extreme environments
Author(s): Charles V. Rice; Anthony Friedline; Karen Johnson; Malcolm M. Zachariah; Kieth J. Thomas III
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Paper Abstract

The bacterial spore is a formidable container of life, protecting the vital contents from chemical attack, antimicrobial agents, heat damage, UV light degradation, and water dehydration. The exact role of the spore components remains in dispute. Nevertheless, water molecules are important in each of these processes. The physical state of water within the bacterial spore has been investigated since the early 1930's. The water is found two states, free or bound, in two different areas, core and non-core. It is established that free water is accessible to diffuse and exchange with deuterated water and that the diffusible water can access all areas of the spore. The presence of bound water has come under recent scrutiny and has been suggested the water within the core is mobile, rather than bound, based on the analysis of deuterium relaxation rates. Using an alternate method, deuterium quadrupole-echo spectroscopy, we are able to distinguish between mobile and immobile water molecules. In the absence of rapid motion, the deuterium spectrum of D2O is dominated by a broad line, whose line shape is used as a characteristic descriptor of molecular motion. The deuterium spectrum of bacterial spores reveals three distinct features: the broad peak of immobilized water, a narrow line of water in rapid motion, and a signal of intermediate width. This third signal is assigned this peak from partially deuterated proteins with the spore in which N-H groups have undergone exchange with water deuterons to form N-D species. As a result of these observations, the nature of water within the spore requires additional explanation to understand how the spore and its water preserve life.

Paper Details

Date Published: 23 September 2011
PDF: 7 pages
Proc. SPIE 8152, Instruments, Methods, and Missions for Astrobiology XIV, 81520V (23 September 2011); doi: 10.1117/12.898766
Show Author Affiliations
Charles V. Rice, The Univ. of Oklahoma (United States)
Anthony Friedline, The Univ. of Oklahoma (United States)
Karen Johnson, The Univ. of Oklahoma (United States)
Malcolm M. Zachariah, The Univ. of Oklahoma (United States)
Kieth J. Thomas III, The Univ. of Oklahoma (United States)

Published in SPIE Proceedings Vol. 8152:
Instruments, Methods, and Missions for Astrobiology XIV
Richard B. Hoover; Paul C. W. Davies; Gilbert V. Levin; Alexei Yu. Rozanov, Editor(s)

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