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International Journal of Microbiology
Volume 2010, Article ID 704170, 5 pages
http://dx.doi.org/10.1155/2010/704170
Research Article

Humidity-Dependent Bacterial Cells Functional Morphometry Investigations Using Atomic Force Microscope

1Department of Biochemical Physics, Orenburg State University, Pobedy Avenue, 13, Orenburg 460018, Russia
2Department of Microbiology, Orenburg State University, Pobedy Avenue, 13, Orenburg 460018, Russia

Received 1 December 2009; Revised 5 March 2010; Accepted 22 April 2010

Academic Editor: Alfons J. M. Stams

Copyright © 2010 Hike Nikiyan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The effect of a relative humidity (RH) in a range of 93–65% on morphological and elastic properties of Bacillus cereus and Escherichia coli cells was evaluated using atomic force microscopy. It is shown that gradual dehumidification of bacteria environment has no significant effect on cell dimensional features and considerably decreases them only at 65% RH. The increasing of the bacteria cell wall roughness and elasticity occurs at the same time. Observed changes indicate that morphological properties of B. cereus are rather stable in wide range of relative humidity, whereas E. coli are more sensitive to drying, significantly increasing roughness and stiffness parameters at RH 84% RH. It is discussed the dependence of the response features on differences in cell wall structure of gram-positive and gram-negative bacterial cells.