5. ANTIBIOSIS AND ANTIBIOTICS
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route of biosynthesis, whereas in many other instances the question
remains open.
In the case of acetate derivation, two main pathways have been
suggested. One involves cyclic precursors of the orsellinic or 6-methylsalicylic acid type. The other postulates an aliphatic polyketomethylene
chain precursor which is susceptible of undergoing various types of
molding on an appropriate enzyme surface.
Examples of compounds thus derived are: gentisic acid and alcohol
(CXXVI), from several species of Penicillium; drosophilin A (CXXVII),
from Drosophih subatrata; sparassol (CXXVIII), from Sparassis ramosa
and Evernia prunasti. Fumigatin (CXXIX), from Aspergillus fumigatus;
spinulosin, from A. fumigatus, P. spinulosum and P. cinerascens; aurantiogliocladin, which is produced, together with the corresponding quinhydrone and gliorosein (CXXX), by Gliocladium sp. and has been
shown, by labeling experiments, to be acetate and formate derived, are
benzoquinone antibiotics more or less related to the coenzymes Q.
OH
OCH 3
Gentisic acid (R = COOH)
and gentisic
alcohol (R = CH 2 OH)
(CXXVI)
Drosophilin A
(CXXVII)
Sparassol
(CXXVIII)
Ο
Ο
Ο
Ο
α In fumigatin: R a = OH; R 2 = H.
In spinulosin: Ri = R 2 = OH.
In aurantiogliocladin: Ri = OCH 3 ; R 2 = CH 3 .
In coenzymes Q n : Ri == OCH 3 ; R 2 = (CH 2 —CH = C—CH 2 )„H.
CH,