Physarum polycephalum pigments

The plasmodia of the wild type of Physarum polycephalum are bright yellow and produce an orange-red pigment that is also present in a white mutant [120]. This compound, named physarorubinic acid (64), binds calcium and other metals very well and this made acquisition of the H-NMR spectrum difficult (line broadening) unless the sample was washed with aq. EDTA solution. The structure contains a decapentaene system and signals at 5 102.4 (C-3), 172.6 (C-7), 174.5 (C-2) and 194.0 (C-4) are characteristic of C-3 acylated tetramic acid unit. 

Mr 453.49, yellow powder, [a]o +7.2° (CH3OH). A pentaene pigment from plasmodia of the slime mold Physarum polycephalum. P. and related compounds appear to play a role as photoreceptors in the life cycle of this myxomycete (see also fuligoru-bin A). 

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