Table 1. Estimates of per cell mRNA inventories for laboratory bacterial cultures (top) and natural marine bacteria (bottom).

Cells	Method	Total RNA content (fg cell−1)	mRNAs cell−1	Reference
Laboratory studies
Escherichia coli	Biochemical analysis	NA	1380	Neidhardt and Umbarger, 1996
Escherichia coli	Single-cell microscopy	NA	1800a	Taniguchi et al., 2010
Vibrio alginolyticus	RNA recovery	28	2288b	Kramer and Singleton, 1992
Natural communities
Coastal bacterioplankton, GA	Internal standard	NA	142–238	Gifford et al., 2011
Bacterioplankton, Amazon Plume	Internal standard	NA	85–255	Satinsky et al., in preparation
Coastal bacterioplankton, GA	RNA recovery	0.6–1.3	96–190b	Gifford et al., 2011
Coastal bacterioplankton, NY	RNA recovery	1.6–5.4	135–458b	Lee and Kemp, 1994
Coastal bacterioplankton, CA	RNA recovery	1.9–9.5	161–805b	Simon and Azam, 1989

Abbreviation: NA, not available.

^aCalculated by extrapolation from 137 genes (see text).

^bCalculated by assuming total RNA contains 4% mRNA by mass (Neidhardt and Umbarger, 1996) and bacterial mRNAs have an average length of 924 nucleotides (Xu et al., 2006) and therefore an average weight of 4.72 × 10⁻⁴ fg.