Titel
Single-cell mass distributions reveal simple rules for achieving steady-state growth
Autor*in
Yanqi Wu
Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology
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Abstract
Optical density is a proxy of total biomass concentration and is commonly used for measuring the growth of bacterial cultures. However, there is a misconception that exponential optical density growth is equivalent to steady-state population growth. Many cells comprise a culture and individuals can differ from one another. Hallmarks of steady-state population growth are stable frequency distributions of cellular properties over time, something total biomass growth alone cannot quantify. Using single-cell mass sensors paired with optical density measurements, we explore when steady-state population growth prevails in typical batch cultures. We find the average cell mass of Escherichia coli and Vibrio cyclitrophicus growing in several media increases by 0.5–1 orders of magnitude within a few hours of inoculation, and that time-invariant mass distributions are only achieved for short periods when cultures are inoculated with low initial biomass concentrations from overnight cultures. These species achieve an effective steady-state after approximately 2.5–4 total biomass doublings in rich media, which can be decomposed to 1 doubling of cell number and 1.5–3 doublings of average cell mass. We also show that typical batch cultures in rich media depart steady-state early in their growth curves at low cell and biomass concentrations. Achieving steady-state population growth in batch culture is a delicate balancing act, so we provide general guidance for commonly used rich media. Quantifying single-cell mass outside of steady-state population growth is an important first step toward understanding how microbes grow in their natural context, where fluctuations pervade at the scale of individuals.
Stichwort
physiologycell sizeVibriosingle-cell methodsmicrofluidics
Objekt-Typ
Sprache
Englisch [eng]
Persistent identifier
phaidra.univie.ac.at/o:2068502
Erschienen in
Titel
mBio
Band
14
Ausgabe
5
ISSN
2150-7511
Erscheinungsdatum
2023
Publication
American Society for Microbiology
Erscheinungsdatum
2023
Zugänglichkeit
Rechte
Rechteangabe
© 2023 Roller et al
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