Studies on the pigments of some plasmodial slime moulds

Khalil, Mohamed Wahid (1974) Studies on the pigments of some plasmodial slime moulds. Doctoral (PhD) thesis, Memorial University of Newfoundland.

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Abstract

Gel permeation chromatography on Sephadex LH-20 and G-10 in aqueous alcoholic solvents has provided a nondestructive method of isolating a consistent pigment preparation from Physarum flavicomum (pigment A-2) and Physarum polycephalum (pigment 3). Both pigments have 'indicator properties' and correspond to substances implicated in light-induced sporulation of several slime moulds. Pigment A-2 (P. flavicomum) has been shown to be homogeneous from electrophoresis studies. The unusual, reversible bathochromic shift of the visible absorption spectrum on protonation is described. Analysis suggests an empirical formula C₁₂H₁₃NO₅ for the protonated pigment. The pigment is not a Schiff's base, contains no amino acids, has a modified polyene chromophore and a molecular weight corresponding to at least twice the empirical formula. Catalytic hydrogenation gives a colourless compound with a pH dependent ultraviolet absorption spectrum which is probably due to the presence of a substituted 2,4-pyronone chromophore. A partial structure based on spectroscopic and analytical data and chemical degradation is proposed.

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