Some Pigments Containing Nitrogen

The striking red colour of the fly agaric Amanita muscaria arises from the presence of betalain pigments. These pigments, which are also responsible for the red colour of beetroots, are formed by the condensation of the amino group of various amino acids with the aldehyde of betalamic acid (7.33). This add and 

The fruiting bodies of several Cortinarius species have a remarkable deep violet colour. Cortinarius violaceous, which is found in deciduous woodland, can concentrate iron by as much as 100-fold over other typical Basidiomycetes. The violet colour has been ascribed to an iron-catechol complex containing dihydroxyphenyl-p-alanine (7.35). The latter is formed by the rearrangement of l-DOPA. 

A characteristic of some Horse mushrooms (Agaricus species) is that they turn yellow when bruised. Examination of the yellow-staining mushroom Agaricus xanthoderma has yielded the azaquinone agaricone (7.36), which is formed by aerial oxidation of a leucophenol in the damaged tissue. 

A combined Cg-Cs-polyketide pathway leads to the styrylpyrone hispidin 

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In addition to pigmented cells, some cyanobacteria contain paler cells known as heterocysts. They have a specialized function of fixing molecular nitrogen. The... 

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