Fig. 2.

SIMSISH analysis for bacterial culture samples.

A. Mixture of different E. coli cell cultures grown, respectively, on media at 1.1%, 10%, 40%, 70% and 99% in ¹³C. E. coli cell culture grown on medium at 40% in ¹³C was pre-hybridized by probe I₆-Eub338-Cy3.

B. Mixture of E. coli cell cultures grown on media from different isotopic composition (respectively 0.4%, 10%, 40%, 70% and 99% in ¹⁵N). The E. coli cell culture grown on the medium containing 40% of ¹⁵N was pre-hybridized by probe I₆-Eub338-Cy3.

C. E. coli cell culture grown on the medium containing 50% of ¹³C and 50% of ¹⁵N was pre-hybridized by probe I₆-Eub338-Cy3. For the three series, image in green represents ¹²⁷I^– secondary ion image (the green intensity scale represents the ¹²⁷I⁻ counts number in NanoSIMS analysis), and image in blue represents ³²S⁻ secondary ion image, acquired to locate protein-containing biomass. The colour scale on the left allows us to easily recognize cell isotopic abundance (each colour corresponds to a 5% increment). Scale bar equals 5 μm.