Gcsfa is more efficient than Gcsfb at expanding erythromyeloid HSPCs cells in the adult zebrafish. (A) Numbers of CFUs (combined erythroid, myeloid, and mixed) per 100 000 cells plated from unfractionated WKM grown with Gcsfa (black line, circles) and Gcsfb (gray line, squares) cytokine concentrations as listed along the x-axis. Each point represents the mean of biological triplicate experiments, and error bars represent the SEM of those triplicate experiments. Statistical significance represents the difference between Gcsfa and Gcsfb effects. *P < .08; **P < .03. (B) Breakdown of different CFU types per 100 000 cells plated from unfractionated WKM grown with 100 ng/mL of Gcsfa and Gcsfb in the presence of Epo. Green bars represent Mpx:GFP⁺ ruffled and spread colonies (Mpx⁺), red bars represent Gata1:DsRed⁺ compact colonies (Gata1⁺), and green/red checkered bars represent colonies with Mpx:GFP⁺ and Gata1:DsRED⁺ cells both present (Mixed). Bars represent the mean of biological duplicate experiments, and error bars represent the SEM of those experiments. Statistical significance represents the difference between Gcsfa and Gcsfb effects. *P < .09; **P < .04. (C) Images of representative colonies derived from unfractionated WKM after stimulation with 100 ng/mL of Gcsfa (left half of panel) or Gcsfb (right half of panel). All cultures also had carp serum, 10% bovine serum albumin, and Epo added. Brightfield (top row), mpx:GFP (middle row), and gata1:DsRed (bottom row) images are shown to illustrate representative colonies seen with these different growth conditions. Mixed colonies are not shown but were present in both cultures. Brightfield and fluorescent images taken on a Leica DMI-6000 inverted fluorescent scope with a Hamamatsu Photonics Orca 3CCD color digital camera at ×400 and processed by Volocity (Perkin Elmer) and Photoshop (Adobe Systems) software.