Fig. 5

STC-1 cells respond to GG ligands. a RT-PCR experiments revealing expression of the three Tas2r transcripts, Tas2r115, Tas2r131 and Tas2r143, in STC-1 cells. Expression of Gnat3 and of the positive control B2m were also confirmed. + cDNA sample, – negative control omitting reverse transcription step. b Immunocytochemistries on STC-1 cells with antibodies against the proteins TAS2R131 and GNAT3. c Fura-2 AM uptake in STC-1 cells measured at 380 nm in a colour-coded map in basal conditions with Hank’s Balanced Salt Solution (HBSS) and during activation by the alarm pheromone 2-sec-butylthiazoline (SBT). d Bar graph representing the response rate induced in STC-1 by GG ligands and bitter tastants tested in e. SBT (299/305); 2,4,5-trimethylthiazoline, TMT (488/491); 2,6-dimethylpyrazine, 2,6-DMP (35/69); 2-propylthietane, 2-PT (127/215); trimethylene sulphide, TS (50/98); 1,3-dithiolane, 1,3-DT (52/98); 2-ethylpyrazine, 2-EP (35/69); 6-propyl-2-thiouracil, PTU (78/84); cycloheximide, CYC (163/163). e Representative calcium transients induced by the alarm pheromone SBT and by the kairomones TMT, 2,6-DMP, 2-PT, TS and 1,3-DT respectively and by the bitter tastants 2-EP, PTU, CYC at (100 μM) and by a control pulse of KCl (10 mM). In b, c, scale bars = 15 μm. In b, nuclei are counterstained in blue with DAPI. In d, n/x = number of cells responding/number of cells tested and viable. In e, fluorescence intensity Fura-2 ratio = F340/F380 is indicated by arbitrary units (a.u.); time is indicated by a horizontal bar