Flow cytometric narrow-angle light scatter and cell size during starvation of Escherichia coli in artificial sea water

Abstract

Flow cytometry was used to study starvation of Escherichia coli in artificial sea water. Flow cytometric narrow‐angle light scatter was compared and assessed in relation to the cell sizes obtained by scanning electron microscopy at low temperature, and by image analysis. A correlation between narrow‐angle light scatter and cell size was not observed, although an acceptable correlation (γ= ‐0.845) between narrow‐angle light scatter and the starvation period was observed. On the other hand, the distribution of narrow‐angle light scatter at any given moment of culture is asymmetric and may be associated with the cell size distribution at the specific moment of starvation.

Assessment of the effects of gramicidin, formaldehyde, and surfactants onEscherichia coli by flow cytometry using nucleic acid and membrane potential dyes

“…2); Gramicidin treatment yields a more homogeneous effect. Detecting the homogeneity of the biocidal effect is of particular interest in cases of heterogeneous initial populations, inherent to growing cultures (8,9,10,11), or starved populations (11,20), or when mixed populations are studied.…”

Current and future applications of flow cytometry in aquatic microbiology

“…In the aquatic ecosystem, their survival is a¡ected by complex environmental stresses and killing agents, which trigger cellular responses that are still poorly understood. The survival of bacteria in aquatic ecosystems has been the subject of many studies [57,58,61,141] and £ow cytometry has also provided new insights, especially into the evaluation of population heterogeneity, DNA changes and membrane potential variations. The multicolour staining used to detect transitional energetic states in cultured organisms [23] may not be applicable to aquatic samples, but shows similar sub-groupings prior of cell integrity as postulated by Joux et al [142,143].…”

Skew-Laplace distribution in Gram-negative bacterial axenic cultures: new insights into intrinsic cellular heterogeneity

“…The relationship between Multisizer II measures and the skew-Laplace distribution was also explored. Previous work has shown that size distributions given by the flow cytometer and other methods are not normal (Koch, 1987;Koch et al, 1996;Ló pez-Amoró s et al, 1994;Vives-Rego et al, 1994Wagensberg et al, 1988). Other distributions have been tested in order to measure particle size in various settings (Bagnold & Barndorff-Nielsen, 1980;Barndorff-Nielsen, 1977;Fieller et al, 1992) and the hyperbolic and skew-Laplace distributions stand out from amongst them.…”

“…More recently, several properties, generalizations and applications of the skew-Laplace distribution have been reported (Kotz et al, 1998), demonstrating that it is a natural and sometimes superior alternative to the conventional Gaussian (normal) distribution. Specifically, the unsuitability of the normal distribution to describe bacterialsize distribution in axenic cultures has been reported repeatedly (Koch, 1987;Vives-Rego et al, 1994;Wagensberg et al, 1988). More recently, the intrinsic cellular heterogeneity of bacterial axenic cultures has been substantiated through flow cytometry and advanced statistical analyses (Vives-Rego et al, 2003).…”