Tetrahydrobiopterin, Nitric Oxide Synthesis and cGMP Concentrations in Mutants of Physarum Polycephalum with Altered Sporulation Behavior

Abstract

Physarum polycephalum is an acellular slime mold. Naturally, Physarum is found in woods and meadows where it exists as macroplasmodia moving on solid surfaces and feeding from microorganisms like bacteria and yeast. Under optimal nutritional conditions plasmodia show a negative phototactical behavior. In case of food limitation, plasmodia move towards light and differentiate into sporangia finally releasing haploid spores. These spores, in proper environment, can germinate into myxamoeba, which can fuse with genetically compatible counterparts to form a zygote. Zygotes grow to macroplasmodia which are single giant cells with multiple well syncronised nuclei, therefore being of interest for cell cycle related studies. Under laboratory conditions the organism can be maintained as macroplasmodia on surfaces, or as microplasmodia in liquid shake culture. In Physarum polycephalum biosynthetic activities for the NOS cofactor tetrahydrobiopterin (BH₄) as well as for folic acid precursors were found (1).