Fig. 1: A peptide toxin, Ta3a, causes the intense long-lasting pain of Tetramorium africanum stings.

a Chromatogram showing fractionation of T. africanum venom using RP-HPLC and activity of fractions on F11 cells (data are mean of two duplicates). Active fractions are coloured orange and peaks are labelled. Inset: T. africanum worker ( ~ 5 mm in length). b [Ca²⁺]_i in F11 cells after addition of f12 and f23 (data are mean of two duplicates). The arrow indicates the time of addition. c Potency of synthetic Ta3a and Ta2a in F11 cells, as monitored by changes in [Ca²⁺]_i (n = 3 independent experiments). d Spontaneous nocifensive behaviours in mice following shallow intraplantar injection of Ta3a (2 or 20 pmol; n = 3 mice per group). Ta2a was inactive up to a dose of 200 pmol. *P < 0.05 (two-way ANOVA with Holm-Šídák’s multiple-comparisons to negative control). e Representative (of 3 independent experiments) pseudocolour images illustrating [Ca²⁺]_i in DRG neurons before (buffer) and after application of Ta3a (100 nM); scale bar = 100 µm. f Time course of individual DRG neuron responses to Ta3a. Each trace represents an individual neuron and the orange trace represents the average response; K⁺, 30 mM KCl (positive control) (representative of 3 independent experiments). g Percentage of DRG neurons activated by Ta3a (100 nM) in the absence or presence of TTX (1 µM). **P = 0.0059 (unpaired t-test; two-sided; n = 3 independent experiments). h Cumulative spontaneous nocifensive behaviours in mice after intraplantar injection of saline (n = 4 mice) or TTX (2 µM) (n = 3 mice), 30 min after injection of Ta3a (60 pmol). ***P = 0.0010 (unpaired t-test; two-sided). Data are expressed as mean ± SEM. Source data are provided as a Source Data file.