Pfizer Handbook of Microbial Metabolites 684 



isolated from Bacillus cereus and vitamin K^ or a related 

 substance from Mycobacterium phlei. 



A lipide cofactor, perhaps a K vitamin or a tocopherol, 

 has been implicated in the conversion of L-gulonolactone 

 into L-ascorbic acid.^^ 



C. ANTHRAQUINONES 



In 1955 three substances were isolated from a yellow 

 sterile mold and were called flavomycelin, rhodomycelin 

 and purpurmycelin.^^ Rhodomycelin is identical with 

 islandicin and flavomycelin vvdth luteoskyrin. Acetone 

 solutions of luteoskyrin turn purple on exposure to light, 

 and purpurmycelin was found to be identical with this 

 irradiation product.^* 



The biosynthesis of the pigments of Penicillium islan- 

 dicum has been studied. ^^ The acetate origin of islandi- 

 cin, skyrin, rubroskyrin (luteoskyrin) and iridoskyrin 

 was established. The results of labeling experiments led 

 to the conclusion that, despite the close structural rela- 

 tionship, these pigments are not interconvertible in vivo, 

 but seem to be derived from a common pre-aromatic 

 stage. Also mutations fail to block formation of any sin- 

 gle pigment. Biogenesis, it was suggested, must not take 

 place by stepwise formations of defined intermediates 

 such as benzene derivatives, but should be dependent 

 throughout on participation of activated acetate. 



An acidic substance related to herqueinone has been 

 isolated.^'' 



A review of quinones as metabolic products of micro- 

 organisms has been published.''' 



There Jiave been two recent pubUcations on the struc- 



92 I. B. Chatterjee, N. C. Kar, N. C. Ghosh and B. C. Guha, Arch. 

 Biochem. and Biophys. 86 154 (1960). 



93 H. Nishikawa, Tohoku J. Agr. Res. 5 285 (1955). 



9* S. Shibata, I. Kitagawa and N. Nishikawa, Pharm. Bull. (Tokyo) 

 5 383 (1957). 



95 Sten Gatenbeck, Acta Chem. Scand. 14 102, 230, 296 (1960). 



96 K. S. Gopalkrishnan and N. Narasimhachari, "Antibiotics," 

 Council of Scientific and Industrial Research, New Delhi, 1958, pp. 

 176-179. 



9^ J. H. Birkinshaw, Planta Med. 7 367 (1959). 



