Figure 7.

Toxins production and detection of virulent Vollum spores in the soil sample. Vollum spores in different concentrations (1 × 10²–1 × 10⁷ CFU/mL) were suspended in 400µl DMEM supplemented with 50% FBS and incubated at 37 °C, under 10% CO₂ for (A) 2 h and (B) 5 h. Soil samples were spiked with 1 × 10²–1 × 10⁴ CFU spores/gram. Samples were processed and resuspended in growth medium for (C) 2 h and (D) 5 h at 37 °C under 10% CO₂. Following incubation, supernatants from each sample in each time point were analyzed for the detection of EF, LF, and PA in the multiplexed immune assay. Results are presented as averages ± SE (error bars) of signal to noise ratios (S/N) from two independent experiments for A-B and 14 different soil samples for C-D. Positive detection was defined as S/N ≥ 2 (black dashed line).