BACKGROUND Natural aromatic polymers, mainly melanins, have potential and current applications in the cosmetic, pharmaceutical and chemical industries. The biotechnological production of this class of compounds is based on tyrosinase-dependent conversion of L-tyrosine and other aromatic substrates into melanins. The purpose of this work was to apply metabolic engineering for generating Escheric...

Melanins are synthesized by organisms of all biological kingdoms and comprise a heterogeneous class of natural pigments. Certain of these polymers have been implicated in the pathogenesis of several important human fungal pathogens. This study investigated whether the fungal skin pathogen Malassezia furfur produces melanin or melanin-like compounds. A melanin-binding monoclonal antibody (MAb) l...

We report the results of an experimental and theoretical study of the electronic and structural properties of a key eumelanin precursor – 5,6,-dihydroxyindole-2-carboxylic acid (DHICA) and its dimeric forms. We have used optical spectroscopy to follow the oxidative polymerization of DHICA to eumelanin, and observe red shifting and broadening of the absorption spectrum as the reaction proceeds. ...

Tyrosinase exhibits catalytic activity for the ortho-hydroxylation of monophenols to diphenols as well as their subsequent oxidation to quinones. Owing to polymerization of these quinones, brown-coloured high-molecular-weight compounds called melanins are generated. The latent precursor form of polyphenol oxidase 4, one of the six tyrosinase isoforms from Agaricus bisporus, was purified to homo...

I report here a series of initial investigations into effects of melanins on the interactions of the three primary species of fungi associated with the southern pine beetle (SPB), and into possible means for mitigating the damaging activities of the melanistic fungus, Ophiostoma minus. Growth of the SPB mutualistic fungus Entomocorticium sp. A on high melanin medium was less than half of the gr...

Indoles and their derivatives, the melan-ins, are among the most important compounds in the body, and perhaps the most neglected (Barr, 1983). This is not because they are uninteresting — they are very reactive, are present in every cell and may be involved in most reactions in the body. (Barr, 1983) summarized the data from which he concluded melanins were the organizing molecules which contro...

After sequential degradation with sodium persulphate and potassium permanganate, the characteristics of the dark pigments from the soil gasteromycete Lycoperdon perlatum were described. Several aromatic acids (phenolic and benzenecarboxylic) were detected by glc-ms of the degradation products, but the aliphatic content of these polymer fractions was predominant, containing a high proportion of ...