326 CONTROL OF REPRODUCTION 



pound with light. The role of component 2 remains problematical. It 

 may have no influence whatever upon fruiting. It may conceivably be 

 either a precursor or a degradation product of component 1. 



SUMMARY 



Plasmodia of Physamm polycephalum, grown either under alternate 

 light and darkness, or in constant darkness, contain two yellow fluo- 

 rescent pigments, which disappear upon fruiting. The two pigments are 

 separable by paper chromatography or column chromatography. 

 Absorption spectra of these compounds in the ultraviolet, visible, and 

 infrared regions, and the fluorescence spectra of these compounds have 

 been studied. Both pigments have been identified as pteridines. 



The spectral properties of one pigment and the shifts in its spectrum 

 with pH are such as to offer an explanation of the effectiveness of low 

 pH and blue light in bringing about the morphogenetic response of 

 fruiting. 



REFERENCES 



Albert, Adrien. 1954. The pteridines. Fortschr. Cheiu. org. Natiirstoffe, 11, 



350-403. 

 Allman, Wm. T., Jr. 1955. Methods for the quantification of Myxomycete plas- 



modia. Ph.D. thesis, Vanderbilt University, Nashville, Tenn. 

 Gates, Marshall. 1947. The chemistry of the pteridines. Chem. Revs., 41, 63- 



95. 

 Gray, W. D. 1938. The effect of light on the fruiting of Myxomycetes. Am. J. 



Botany, 25, 511-22. 

 . 1939. The relation of pH and temperature to the fruiting of Physamm 



polycephalum. Am. J. Botany, 26, 709-14. 



-. 1953. Further studies on the fruiting of Physarum polycephalum. 



Mycologia, 45, 817-24. 



Nathan, H. A., S. H. Hutner, and H. L. Levin. 1956. Independent require- 

 ments for Crithidia factor and folic acid in a trypanosomid flagellate. Nature, 

 178, 741-42. 



Seifriz, W., and M. Zetzmann. 1935. A slime mould pigment as indicator of 

 acidity. Protoplasma, 23, 175-79. 



Wolstenholme, G. E. W., and M. P. Cameron. 1954. Chemistry and Biology 

 of Pteridines. Ciba Foundation Symposium. Little, Brown & Co., Boston, 

 Mass. 



