Morphology of adult zebrafish hematopoietic cells. (A-D) Peripheral blood smears showing: (A) bilobed neutrophil, (B) eosinophil, (C) lymphocyte and nucleated erythrocytes, and (D) aggregate of thrombocytes with visible cytoplasmic projections. (E-G) Kidney marrow cell cytospin showing: (E) progression of granulocyte maturation from immature (i,ii) to mature (iii) forms, (F) identification of granulocytes by myeloperoxidase cytochemistry, and (G) identification of granulocytes by Sudan black cytochemistry. (H) A cluster of hematopoietic cells (closed arrowhead) nestled between renal tubules (open arrowhead) (hematoxylin and eosin stained section). (I) FACS analysis of kidney marrow cells by forward scatter (FSC) and side scatter (SSC) separates erythroid (red), myelomonocytic (green), lymphocytic (blue), and progenitor (orange) cell populations. Bars represent 10μm (A-G) and 20μm (H). Microscopy was performed using a Nikon Optiphot-2 microscope equipped with a 40×/1.0 and 100×/1.40 oil objective. Images were obtained using a Zeiss Axiocam MRc5 digital camera (Carl Zeiss) with Axiovision AC software (Release 4.5). Images were processed using Adobe Photoshop CS2 9.0 and Adobe Illustrator CS2 12.0.1 (Adobe Systems).