Figure 3.

Chemical detection of F₄₂₀ in dominant soil phyla. (a) HPLC traces showing F₄₂₀ from cell lysates of different species relative to a purified F₄₂₀ standard. The traces show the intensity of the fluorescence emitted (λ_excitation=420 nm, λ_emission=480 nm). The dotted lines show the times at which each species started to elute. (b) Mass spectra confirming the molecular weight and oligoglutamate side chain length of the purified F₄₂₀ standard. (c) Fluorescence emission spectra of F₄₂₀ from cell lysates of five different species against a purified F₄₂₀ standard.