Extended Data Fig. 7: Discovery of a myeloid lineage phagocytic population.

a, FACS analysis of B. schlosseri cells that are fluorescently positive in one of three phagocytosis assays performed: (first and second from left) phagocytosis of green fluorescent beads, (third) phagocytosis of V. diazotrophicus labelled with AF647, and (fourth) allogeneic phagocytosis. Three phagocytic populations were identified: amoebocytes (A), myeloid cells (M), and large phagocytes (LP). The experiment was repeated twice. The myeloid cells were the main contributors to phagocytosis, contributing more than 40% to each of the phagocytosis assays. The large phagocytes contribute mainly to allogeneic phagocytosis compared to the other assays. b, Live images of the three isolated phagocytic populations. The experiment was performed three times. Scale bar, 20 μm. c, We isolated the three main phagocytic populations and a small cell population (CP3) as a control, and incubated each one with fluorescent beads to validate the engulfment capacity of each population. The experiment was repeated twice. Plots show FACS analysis of green fluorescent bead phagocytosis by sorted populations. d, Amoebocytes, myeloid cells, and large phagocytes all had significantly higher engulfment rates than the small cell population. Moreover, amoebocytes and myeloid cells had significantly higher cell percentages than the large phagocyte population. Percentage analysis was carried out on two samples for each sorted population. Unpaired t-test, two-tailed; *P < 0.05, data shown as mean. e, Representative confocal images of the three phagocytic populations after engulfment of beads. Scale bar, 20 μm. f, ImageStream analysis confirmed that the three phagocytic populations assayed engulfed the beads. The positive cells had mainly the morphology of amoebocytes, myeloid cells, or large phagocytes. The experiment was performed once on ImageStream. Representative images of the three phagocytic populations after engulfment of beads. Scale bar, 7 μm.