Melanins are the most prevalent pigments in animals and are involved in visual communication by producing colored traits that often evolve as intraspecific signals of quality. Identifying and quantifying melanins are therefore essential to understand the function and evolution of melanin-based signals. However, the analysis of melanins is difficult due to their insolubility and the lack of simp...

Melanins are universal biopolymers, the main biological function of which is to protect living organisms from adverse factors. Interest in these dark pigments arises due prospects for their use medicine, cosmeceuticals, bioremediation, bioelectronics, and other fields. In this work, a complex scheme was developed isolate melanins lichen Leptogium furfuraceum (Harm.), symbiotic extremophilic org...

INTRODUCTION Melanins are high-molecular-weight pigments that are ubiquitous in nature and can also be synthesized in the laboratory from a variety of precursors. Melanins possess numerous interesting physicochemical characteristics, including electromagnetic radiation absorption properties and ability to chelate metals. We have recently reported that melanin has remarkable ionizing-radiation-s...

D. C. dark - and photoconductivity measurements were performed with synthetic melanins prepared by oxidative polymerization of dopamine, adrenaline, adrenochrome and adrenolutin. The melanins examined show significant differences in conductivity, thermal activation energy and photocurrent intensity values. The differences in semiconductor properties observed between the melanins reflect the str...

The fungal pathogens Cryptococcus neoformans and Histoplasma capsulatum produce melanin-like pigments in the presence of L-dopa in vitro and during mammalian infection. We investigated whether melanization affected the susceptibilities of the fungi to amphotericin B, caspofungin, fluconazole, itraconazole, or flucytosine (5FC). Using the standard macrodilution MIC protocol (the M27A protocol) o...

Melanin pigments are broadly distributed in nature - from bacteria to fungi to plants and animals. However, many previous attempts to identify melanins in spiders were unsuccessful, suggesting that these otherwise ubiquitous pigments were lost during spider evolution. Yet, spiders exhibit many dark colours similar to those produced by melanins in other organisms, and the low solubility of melan...

BACKGROUND Melanin, a high-molecular weight pigment that is ubiquitous in nature, protects melanized microorganisms against high doses of ionizing radiation. However, the physics of melanin interaction with ionizing radiation is unknown. METHODOLOGY/PRINCIPAL FINDINGS We rationally designed melanins from either 5-S-cysteinyl-DOPA, L-cysteine/L-DOPA, or L-DOPA with diverse structures as shown ...

The role of 5,6-dihydroxyindole-2-carboxylic acid (DHICA) in the biosynthesis of melanins has been studied by using the incorporation of specifically radiolabelled melanogenic precursors into melanins formed by melanocytes growing in vitro and in vivo. Extracts of mouse melanocytes and intact viable melanocytes were found to incorporate into melanin from 25% to more than 60% of [1-14C]tyrosine....

Melanins are notoriously difficult to study because they are amorphous, insoluble and often associated with other biological materials. Consequently, there is a dearth of structural techniques to study this enigmatic pigment. Current models of melanin structure envision the stacking of planar structures. X ray diffraction has historically been used to deduce stacking parameters. In this study w...

Melanins are negatively charged, hydrophobic pigments of high molecular weight (54, 88, 95, 139) that are composed of polymerized phenolic and/or indolic compounds (Fig. 1) (45, 128). Melanins are produced by organisms in all biological kingdoms, including a wide variety of pathogenic bacteria, fungi, and helminths (reviewed in reference 90). Remarkably little is known about the structures of m...