Introduction Tetrahymena thermophila 1 2 Tetrahymena Tetrahymena T. thermophila 1 3 4 2 2 2+ 1 1 3 T. thermophila 1 in vivo D T. thermophila 1 O T. thermophila 4 4 T. thermophila 5 6 3 7 T. thermophila T. thermophila Materials and methods Cell cultures T. thermophila 8 Chemicals and solutions 2 Behavioral assays 1 9 10 T. thermophila Western blots 2 EIA assays NO assays were carried out using 2-day-old cell cultures. Cells were washed twice in buffer and diluted to a final concentration of approximately 720 cells/ml. Cells were exposed to 100 μM GTP-γ-S for approximately 30 s, then spun down in a bench-top microcentrifuge for 30 s. Control cells were spun under identical conditions except that no GTP was added to the solution. Supernatant from both sets of cells was analyzed for NO using a kit from BIOMOL according to the manufacturer’s instructions. 6 Immunofluorescence 11 Results Tetrahymena, 1 3 1 50 Fig. 1 Tetrahymena  Error bars 50  2 9 50 2 Fig. 2 Tetrahymena closed circles open circles 50  T. thermophila 12 n T. thermophila 9 n  3 3 3 Fig. 3 Tetrahymena.  a–c Tetrahymena a b c  d lane 2 lane 3  first lane  3 12 50 3 13 3 2 5 Tetrahymena 2 14 15 3 5 50 5 17 5 18 Tetrahymena 13 18 6 6 Tetrahymena 6 6 50 n 20 T. thermophila 20 7 7 Tetrahymena 7 7 50 Tetrahymena n 8 3 Discussion 1 2 3 4 5 6 7 8 Fig. 4 Tetrahymena. 50  Fig. 5  Tetrahymena a Tetrahymena. 50 b Tetrahymena. 50  Fig. 6 Tetrahymena a Tetrahymena. 50 b Tetrahymena 50  Fig. 7 Tetrahymena a Tetrahymena 50 b Tetrahymena 50  Fig. 8 26 32 33  13 18 21 2 2 3 3 22 3 3 3 4 Tetrahymena 24 25 26 Tetrahymena 10 13 4 3 3 5 3 Tetrahymena 5 18 13 T. thermophila 27 Leishmania donovani, 28 6 7 Tetrahymena 13 18 19 19 L. donovani 28 Tetrahymena 8 Tetrahymena Tetrahymena 29 30 31 Tetrahymena 32 33 Chlamydomonas 8 T. thermophila Tetrahymena Tetrahymena Tetrahymena Tetrahymena 33 Tetrahymena