This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Norland, S. Articles by Heldal, M. Search for Related Content PubMed PubMed Citation Articles by Norland, S. Articles by Heldal, M. Agricola Articles by Norland, S. Articles by Heldal, M.

 Previous Article  |  Next Article 

Appl. Environ. Microbiol., Apr 1995, 1357-1362, Vol 61, No. 4
Copyright © 1995, American Society for Microbiology

Light Element Analysis of Individual Bacteria by X-Ray Microanalysis

S Norland, KM Fagerbakke and M Heldal
Department of Microbiology, University of Bergen, N-5020 Bergen, Norway

A method based on X-ray microanalysis (XRMA) with the transmission electron microscope for measurement of total amounts of elements in single microbial cells has been developed. All major elements in cells except hydrogen can be measured simultaneously. XRMA provided N/C ratios (means (plusmn) standard errors of the mean) for stationary-phase and growing Escherichia coli of 0.23 (plusmn) 0.01 and 0.30 (plusmn) 0.01, respectively, while CHN analysis gave values of 0.276 and 0.307, respectively, for samples from the same cultures. Analyses of free coccoliths from Emiliana huxleyi provided weight fractions close to those of CaCO(inf3): 0.35 (plusmn) 0.01, 0.15 (plusmn) 0.01, and 0.47 (plusmn) 0.01 for calcium, carbon, and oxygen, respectively. Calibration is based on monodisperse latex beads and on microdrops of defined compounds. Elements in particles in the size range from 5 fg to 500 pg are measured with a relative precision between 500 and 5,000 ppm, depending on size. As a single-cell method, XRMA avoids the shortcomings of commonly used fractionation techniques associated with bulk methods, which are based on centrifugation or filtration. On the basis of morphology and XRMA, particles may be classified more precisely into groups (e.g., biotic versus abiotic) than is possible by bulk methods. Single-cell elemental analysis may provide insight into topics like nutritional and energetic status, macromolecular composition, and (by multivariate statistics) community structure.

This article has been cited by other articles:

• Vrede, K., Heldal, M., Norland, S., Bratbak, G. (2002). Elemental Composition (C, N, P) and Cell Volume of Exponentially Growing and Nutrient-Limited Bacterioplankton. Appl. Environ. Microbiol. 68: 2965-2971 [Abstract] [Full Text]