Fig. 1: Single-cell analysis of Anabaena sp. ATCC 33047 growth and differentiation.

a–c Representative frames showing Anabaena growing on the microscope in BG-11 media without supplemental nitrogen (BG11_-N). Images were collected in the brightfield and chlorophyll fluorescence channels. A merged image is also shown (chlorophyll fluorescence shown in red). The carets indicate heterocysts, which are identified both by their increased size and the loss of chlorophyll fluorescence. The magenta caret indicates a cell in the early stages of differentiation, and the yellow caret indicates a previously differentiated heterocyst. Scale bars are 10 µm. d–g Representative frames showing cells growing in BG11_-N-Buffer media supplemented with calcium chloride and bicarbonate (BG11_-N-Buffer + Ca). Initial seed crystals were observed (indicated by carets). We observed initial crystal growth (seen in frame e), likely due to temperature change as the sample was placed in the growth chamber. Some crystals (yellow caret) showed increased growth due to interaction with the cells. Scale bars are 20 µm. h, i Crystal growth was tracked over time (Full timelapse shown in Supplementary Movie S3). Scale bar is 50 µm. h shows the merged frame after 50.5 h and i shows the mask labeling the crystals. j Crystal area over time. The zoomed-in region shown in (d–g) is indicated in magenta.