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Proceedings Paper

Ability of bacteria to promote the formation of fine-grained minerals on their surfaces
Author(s): Terry J. Beveridge
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Paper Abstract

The surfaces of bacteria are highly interactive with their environment. Whether the bacterium is gram-negative or gram- positive, most surfaces are charged at neutral pH because of the ionization of the reactive chemical groups which stud them. Since prokaryotes have a high surface area-to-volume ratio, this can have surprising ramifications. For example, many bacteria can concentrate dilute environmental metals and silicates on their surfaces and initiate the development of fine-grained minerals. In natural environments, it is not unusual to find such bacteria closely associated with the minerals which they have helped develop. Since bacteria usually prefer to grow as biofilms on macroscopic surfaces in most natural ecosystems (supposedly to take advances of the nutrient concentrative effect of the interface), they can form films micrometers -to-mm-thick. Using a gram-negative bacterial model, we have found that lipopolysaccharide (a surface component) is important in the initial attachment of the bacterium to the substratum. This macromolecule is also important for the entrapment of metals and the instigation of mineral development. Eventually, biofilms become so mineralized that the shape and form of the constituent bacteria are preserved and embedded in the rock as it forms. These mineralized bacteria are called `microfossils' and it is possible that the same set of circumstances could have preserved small lifeforms on Mars given similar environmental conditions.

Paper Details

Date Published: 11 July 1997
PDF: 10 pages
Proc. SPIE 3111, Instruments, Methods, and Missions for the Investigation of Extraterrestrial Microorganisms, (11 July 1997); doi: 10.1117/12.278792
Show Author Affiliations
Terry J. Beveridge, Univ. of Guelph (Canada)

Published in SPIE Proceedings Vol. 3111:
Instruments, Methods, and Missions for the Investigation of Extraterrestrial Microorganisms
Richard B. Hoover, Editor(s)

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