Fig. 8

Carbon and nitrogen isotope ratios at different incubation time points. a and b Scatter dot plots (median in black lines) of the ¹³C and ¹⁵N atom percent enrichment within cells for each incubation time point, respectively. The dashed lines are the results of the fitting analyses with the residual sum of squares (RSS) of 0.0193 in a and 9.0457 in b. c Scatter plot of 330 LHC-1 cells’ carbon and nitrogen ratio in eight incubation time points. Each dot represents a single cell. Many of the data points are gathered around the lower left of the plot indicating their intracellular isotope levels are close to natural abundances. The natural environmental ¹³C⁻/¹²C⁻ ratio value 0.0112 and ¹⁵N⁻/¹⁴N⁻ ratio value 0.0037 are indicated as red lines. Both the plot and isotope images show that some cells of 8 h and 17.5 h tend to accumulate more ¹⁵N atoms, which may represent a unique metabolic status. d Scatter dot plots (median in black lines) of the cell length distribution for each incubation time point. The dashed line is the result of the fitting analyses with the RSS of 0.4715