Numerous flow cytometric analyses are based on DNA content studies. We have considered firstly monoparametric cell cycle analyses, which only take DNA content into account, but are sometimes of limited interest. Then, we have presented multiparametric analyses, which can be used to improve cycle phase identification by taking simultaneously into account DNA and other cellular components, or by considering some events occurring during cell cycle. Finally, we have discussed monoparametric and multiparametric cell cycle analysis interest in various application fields, particularly in pharmacology, toxicology, tumoral pathology and higher plant system studies.

Background: Apoptosis is currently studied by flow cytometry with mitochondrial membrane potential (⌬ mt ) and membrane integrity fluorochromes. Rhodamine 123 and DiOC 6 (3) remain controversial to identify cells displaying a low ⌬ mt . JC-1 constitutes a good ⌬ mt indicator, due to a fluorescence shift from green to orange emission, according to the increase in ⌬ mt . Nevertheless, it is not feasible to analyze it simultaneously with propidium iodide. Among available fluorescent probes, TOTO-3 seems to be a good candidate for double staining with JC-1. Methods: Cell death of HaCaT cells was induced by H 2 O 2 and FasL. Samples were stained with DiOC 6 (3)/IP or JC-1/TOTO-3 then analyzed by flow cytometry. Results were supported by confocal microscopy analyses of mitochondrial membrane potential. Moreover, cell morphology was determined on the sorted subpopulations defined on the basis of staining (JC-1 versus TOTO-3).

This review focuses on the recent applications of flow cytometry (FCM) in microbiological research (1987-mid 1992). It tries to give a scope of the important breakthroughs which occurred in this field during this period. The technical difficulties of microorganism analysis by flow cytometry is briefly appraised. The significance and the limits of the different microbial cell parameters attainable by flow analyses are systematically evaluated: light scatter for cell size and structure, fluorescence measurements for quantification of cellular components, microbial antigen detection and cell physiological activity estimation. Emphasis is given on the new technological advances which appeared in the last two years. The second part of the review is devoted to the analysis of the usefulness of flow cytometric approach in the different fields of microbiology: fundamental studies in microbial physiology, differentiation, microbial ecology and aquatic sciences, medical microbiology, parasitology, microbial pharmacology and biotechnology.

Background This study was undertaken in mice to develop a reproducible procedure of cell permeabilization, allowing intracellular protein staining by immunofluorescence (i.e., Bcl‐2) without losing surface labeling especially for lectins (i.e., B220 and peanut agglutinin [PNA]). This article reports results obtained with different permeabilization protocols. Methods Lymphoid cells were extracted and prepared from Peyer's patches and spleen. After surface labeling using anti‐B220‐Cy‐chrome and PNA‐biotin/streptavidin‐phycoerythrin, we comparatively tested three permeabilization protocols: saponin 0.3%, methanol 70%, and the commercial kit Dako Intrastain. Final Bcl‐2 staining was performed and cells were analyzed by flow cytometry. Results With 0.3% saponin as the permeabilization reagent, a significant loss of lectin labeling was observed when comparing mono PNA and triple (i.e., B220‐PNA‐Bcl‐2) staining (74.8% and 22.5% positive cells, respectively). Quality of PNA staining was conserved with Intrastain when comparing multiparametric versus monoparametric stainings (82.4% of positive cells versus 78.3%, respectively). Intrastain preserved scatter characteristics (69.9% of total cells in the lymphocyte gate with Intrastain versus 13.7% with saponin 0.3% and 20.9% with methanol 70%). This protocol has been used for a preliminary multiparametric analysis in order to quantify Bcl‐2 expression in PNA/B220‐positive cells. Conclusion This protocol may be useful to assess simultaneously lectin cell surface labeling and intracellular target staining. Cytometry 41:55–61, 2000 © 2000 Wiley‐Liss, Inc.

To study the interaction between cocultured Listeria monocytogenes and an antagonistic Leuconostoc strain producing an anti-Listeria bacteriocin, flow cytometry, a technique allowing on-line and real-time analysis, was used along with classical microbiological methods. Culture methods and flow cytometric measurements of the mixed culture over time point to a bactericidal action of the lactic acid-producing bacterial strain against L.