Melanins are a class of natural pigments associated with a wide range of biological functions, including microbial virulence, energy transduction, and protection against solar radiation. Because of their insolubility and structural heterogeneity, solid-state nuclear magnetic resonance (NMR) spectroscopy provides an unprecedented means to define the molecular architecture of these enigmatic pigm...

Primary malignant melanoma of cervix is a rare entity. A case of primary malignant melanoma of cervix presented with vaginal discharge and black colored growth over cervix. Histology showed malignant pleomorphic cells with melanin pigment in the cytoplasm.

Do genetic correlations among phenotypic characters reflect developmental organization or functional coadaptation of the characters? We test these hypotheses for the wing melanin pattern of Pieris occidentalis butterflies, by comparing estimated genetic correlations among wing melanin characters with a priori predictions of the developmental organization and the functional (thermoregulatory) or...

Lichens are unique extremophilic organisms due to their phenomenal resistance adverse environmental factors, including ultraviolet (UV) irradiation. Melanization plays a special role in the protection of lichens from UV-B stress. In present study, we analyzed binding melanins with components cell walls mycobiont upper cortex melanized lichen thalli Lobaria pulmonaria. Using scanning electron an...

The Toxoplasma gondii genome contains two aromatic amino acid hydroxylase genes, AAH1 and AAH2 encode proteins that produce L-DOPA, which can serve as a precursor of catecholamine neurotransmitters. It has been suggested that this pathway elevates host dopamine levels thus making infected rodents less fearful of their definitive Felidae hosts. However, L-DOPA is also a structural precursor of m...

Melanins are natural pigments distributed in living organisms and they are responsible for pigmentation of surface structure. In the present work, gel exclusion chromatography, spectrophotometric, and dielectric relaxation techniques were used to characterize DOPA melanin before and after irradiation with 60 Co gamma rays in the range of 5 to 50 Gy. The results show that the studied melanin is ...

Tyrosinase is a type 3 copper enzyme that catalyzes the ortho-hydroxylation of monophenols to diphenols as well as their subsequent oxidation to quinones, which are precursors for the biosynthesis of melanins. The first plant tyrosinase from walnut leaves (Juglans regia) was purified to homogeneity and crystallized. During the purification, two forms of the enzyme differing only in their C-term...