Increase in cell dry weight with increasing growth rate and under photoinhibition (see 'Comments' section)

Range 5.3±1.7 pg/cell to 11.3±2.3 pg/cell under photoinhibition 8.6±2.6 pg/cell
Organism Cyanobacteria Synechocystis PCC 6803
Reference Zavřel T et al., Quantitative insights into the cyanobacterial cell economy. Elife. 2019 Feb 4 8. pii: e42508. DOI: 10.7554/eLife.42508 p.6 2nd paragraphPubMed ID30714903
Method P.2 bottom paragraph: "The Synechocystis substrain GT-L (Zavřel et al., 2015b) was cultivated in flat panel photobioreactors (Figure 1A) using at least 5 independent reactors in a quasi-continuous (turbidostat) regime (Figure 1B), with red light intensities of 27.5 − 1100 μmol(photons) m^-2s^-1, supplemented with a blue light intensity of 27.5 μmol(photons) m^-2s^-1. The addition of blue light avoids possible growth limitations in the absence of short wavelength photons (Golden, 1995). Steady-state specific growth rates in turbidostat mode were calculated from monitoring the optical density measured at a wavelength of 680 nm (OD680) as well as from the rate of depletion of spare cultivation medium (as measured by top loading balances). Both methods resulted in similar average values (Figure 1C). Estimation of the specific growth rates based on the medium depletion, however, exhibited higher variance. For further analysis, therefore, only values obtained from the OD680 signal are reported."
Comments P.6 2nd paragraph: "Changes in cell volume were reflected in changes in cellular dry weight. Dry weight per cell increased from 5.3±1.7 pg/cell for the slowest specific growth rate to 11.3±2.3 pg/cell at the maximal growth rate. Under photoinhibition, cellular dry weight again decreased to 8.6±2.6 pg/cell (Figure 2B, Figure 2—figure supplement 1). The ratio of cellular dry weight to cell volume showed no significant change for different growth rates (Kruskal-Wallis test: p−value=0.077)." Comment from Ron Milo: "Based on reported mass and volume the density seems too high and thus there might be some problem."
Entered by Uri M
ID 116738