668
R. H. THOMSON
ing the naphthoquinones in echinoids and holothuroids, and the anthraquinones in crinoids. There is no obvious connection between the plant
and animal pigments.
5. Bacteria
Although many bacteria produce pigments, few have been examined
in detail. In recent years, the antibiotic properties of some of these
have stimulated chemical investigation, and a number have now been
recognized as quinones, several of a new type not found hitherto in
nature. In contrast to the fungi, anthraquinones and benzoquinones are
conspicuous by their absence. The Actinomycetales appear to be the
most abundant source, but this may only reflect the attention they have
received. However, the earliest record is somewhat dubious. In 1899,
Beijerinck (151) claimed to have detected p-benzoquinone in cultures
of Streptomyces olivochromogenus obtained from garden soil, and although this was not established, there was some indication of quinone
formation, but only in media containing protein. In this respect, the
organism behaves like other members of the "chromogenus" group of
Streptomycetes in producing soluble brown pigments when grown on
protein-containing media, and Beijerinck's quinone was most probably
derived from tyrosine by enzymatic oxidation. According to this author,
the quinone played an important part in humus formation, and the
view is still held (152) that humic acids in soil are formed via quinones
by polymerization and/or combination with protein, the quinones being
produced by microorganisms from phenolic materials. The formation of
quinones at an intermediate stage in the oxidative metabolism of phenols
by bacteria is well established (153), and phenols may be available in
soil as lignin degradation products or as leaf polyphenols, or they may
be biosynthesized from carbohydrates by microorganisms.
The production of litmus-like pigments (i.e. pigments showing a redblue, acid-base indicator change) by Actinomycetales has been observed
for many years (154), and some at least are quinones. One of these is
granaticin, C22H20O10 (155), SL deep-red antibiotic product of Streptomyces olivaceus (Waksman) Waksman and Henrici, which appears to
be a polyhydroxypolycyclicquinone probably related to the pyrromycinones (see below); actinorhodin (156) is another. This latter coloring
matter, obtained from Streptomyces coelicolor (Müller) Waksman and
Henrici, is a derivative of dinaphthazarin (CXXV). Several derivatives
of naphthazarin (5,8-dihydroxy-l,4-naphthoquinone) have been isolated
from the lower fungi, flowering plants, and sea urchins, but actinorhodin
is the only dinaphthazarin, indeed the only dinaphthoquinone, isolated
R. H. THOMSON
ing the naphthoquinones in echinoids and holothuroids, and the anthraquinones in crinoids. There is no obvious connection between the plant
and animal pigments.
5. Bacteria
Although many bacteria produce pigments, few have been examined
in detail. In recent years, the antibiotic properties of some of these
have stimulated chemical investigation, and a number have now been
recognized as quinones, several of a new type not found hitherto in
nature. In contrast to the fungi, anthraquinones and benzoquinones are
conspicuous by their absence. The Actinomycetales appear to be the
most abundant source, but this may only reflect the attention they have
received. However, the earliest record is somewhat dubious. In 1899,
Beijerinck (151) claimed to have detected p-benzoquinone in cultures
of Streptomyces olivochromogenus obtained from garden soil, and although this was not established, there was some indication of quinone
formation, but only in media containing protein. In this respect, the
organism behaves like other members of the "chromogenus" group of
Streptomycetes in producing soluble brown pigments when grown on
protein-containing media, and Beijerinck's quinone was most probably
derived from tyrosine by enzymatic oxidation. According to this author,
the quinone played an important part in humus formation, and the
view is still held (152) that humic acids in soil are formed via quinones
by polymerization and/or combination with protein, the quinones being
produced by microorganisms from phenolic materials. The formation of
quinones at an intermediate stage in the oxidative metabolism of phenols
by bacteria is well established (153), and phenols may be available in
soil as lignin degradation products or as leaf polyphenols, or they may
be biosynthesized from carbohydrates by microorganisms.
The production of litmus-like pigments (i.e. pigments showing a redblue, acid-base indicator change) by Actinomycetales has been observed
for many years (154), and some at least are quinones. One of these is
granaticin, C22H20O10 (155), SL deep-red antibiotic product of Streptomyces olivaceus (Waksman) Waksman and Henrici, which appears to
be a polyhydroxypolycyclicquinone probably related to the pyrromycinones (see below); actinorhodin (156) is another. This latter coloring
matter, obtained from Streptomyces coelicolor (Müller) Waksman and
Henrici, is a derivative of dinaphthazarin (CXXV). Several derivatives
of naphthazarin (5,8-dihydroxy-l,4-naphthoquinone) have been isolated
from the lower fungi, flowering plants, and sea urchins, but actinorhodin
is the only dinaphthazarin, indeed the only dinaphthoquinone, isolated