Fig. 1. Uptake of albumin and hemoglobin by tick midgut digest cells. Digest cells were incubated for 4 h in culture medium containing albumin or hemoglobin labeled with rhodamine. Incubation conditions were (A,B) 1 µmol l^–1 rhodamine–hemoglobin; (C,D) 1 µmol l^–1 rhodamine–hemoglobin plus 100 µmol l^–1 unlabeled hemoglobin; (E,F) 1 µmol l^–1 rhodamine–albumin; (G,H) 1 µmol l^–1 rhodamine–albumin plus 100 µmol l^–1 unlabeled albumin. (A,C,E,G) Differential interference contrast (DIC) images; (B,D,F,H) rhodamine fluorescence. Scale bar, 10 µm. Large hemoglobin-accumulating vesicles (asterisks) and small albumin-accumulating vesicles (arrows) are indicated in the figure. Hemosomes are seen as brown-colored structures on DIC panels and are not labeled by any of the proteins conjugated to rhodamine.