The optical scattering coefficient of a dilute, well-solubilized eumelanin solution has been accurately measured as a function of incident wavelength, and found to contribute <6% of the total optical attenuation between 210 and 325 nm. At longer wavelengths (325-800 nm), the scattering was less than the minimum sensitivity of our instrument. This indicates that ultraviolet and visible optical d...

The expression of Klebsiella pneumoniae hpaA and hpaH genes, which code for 4-hydroxyphenylacetic acid hydroxylase in Escherichia coli K-12 derivative strains, is associated with the production of a dark brown pigment in the cultures. This pigment has been identified as a polymer which shows several of the characteristics reported for microbial melanins and results from the oxidative activity o...

The melanins are an important class of pigmentary macromolecule found throughout nature. Eumelanin is the predominant form in humans, and acts as our primary photoprotectant. The structure-property-function relationships that dictate the behavior of these biomaterials are still poorly understood. In particular, major questions still remain concerning the basic structural unit. It is well accept...

Evidence is presented that the resistance of Aspergillus nidulans hyphae to lysis by a beta-(1-->3) glucanase-chitinase mixture results from the presence of melanin in the fungal walls. The resistance of the walls to digestion was directly correlated with the melanin content of the mycelium. A melanin-less mutant of A. nidulans was highly susceptible to hydrolysis by the enzyme mixture. Preincu...