Eubacteria usually show weaker staining properties; their
staining of the substratum is usually light in colour and appears
only when it is in an advanced decomposition stage.
Actinomycetes, however, are among microorganisms producing
dyes of intense colours. Their colonies secrete into
the substratum, and/or store in their mycelia and spores,
dyes of a wide range of colours (listed above). For example,
an intensely blue actinomycete strain has been isolated from
toothbrushes in the Auschwitz Museum. Parchment is deteriorated
by Streptomyces =micarius (Karbowska-Berent
and Strzelczyk, 2000) which produces a deep purple substance,
as well as by other actinomycetes. Mural paintings
are devastated by actinomycetes that are white,