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Viability and membrane potential analysis of Bacillus megaterium cells by impedance flow cytometry
Author(s) -
David F.,
Hebeisen M.,
Schade G.,
FrancoLara E.,
Di Berardino M.
Publication year - 2012
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.23345
Subject(s) - bacillus megaterium , flow cytometry , viability assay , biology , cell counting , cytometry , cell , microbiology and biotechnology , biophysics , chemistry , bacteria , biochemistry , cell cycle , genetics
Abstract Single cell analysis is an important tool to gain deeper insights into microbial physiology for the characterization and optimization of bioprocesses. In this study a novel single cell analysis technique was applied for estimating viability and membrane potential (MP) of Bacillus megaterium cells cultured in minimal medium. Its measurement principle is based on the analysis of the electrical cell properties and is called impedance flow cytometry (IFC). Comparatively, state‐of‐the‐art fluorescence‐based flow cytometry (FCM) was used to verify the results obtained by IFC. Viability and MP analyses were performed with cells at different well‐defined growth stages, focusing mainly on exponential and stationary phase cells, as well as on dead cells. This was done by PI and DiOC 2 (3) staining assays in FCM and by impedance measurements at 0.5 and 10 MHz in IFC. In addition, transition growth stages of long‐term cultures and agar plate colonies were characterized with both methods. FCM and IFC analyses of all experiments gave comparable results, quantitatively and qualitatively, indicating that IFC is an equivalent technique to FCM for the study of physiological cell states of bacteria. Biotechnol. Bioeng. 2012; 109:483–492. © 2011 Wiley Periodicals, Inc.