Melanins are complex biological pigments formed by the oxidative polymerization of phenolic and/or indolic compounds. These pigments have been implicated in the pathogenesis of some microbial infections, malignancies, degenerative disorders, and autoimmune diseases. Recent studies have demonstrated that melanins have antigenic and anti-inflammatory properties. These findings led us to further e...

Optical measurements of the pigments of the retinal pigment epithelium (RPE) and choroid were made on 38 human autopsy eyes of both blacks and whites, varying in age between 2 wk and 90 yr old. Lipofuscin in melanin-bleached RPE was measured as fluorescence at 470 mm following excitation at 365 nm and was found to be proportional to fluorescence measured at 560 nm in unbleached tissue. Transmis...

In pathogenic fungi, melanin contributes to virulence, allowing tissue invasion and inactivation of the plant defence system, but has never been implicated as a factor for host cell death, or as a light-activated phytotoxin. Our research shows that melanin synthesized by the fungal banana pathogen Mycosphaerella fijiensis acts as a virulence factor through the photogeneration of singlet molecul...

Metastatic melanoma remains an incurable disease, and there is a great need for novel therapeutic modalities. We have recently identified melanin as a target for radionuclide therapy of melanoma and demonstrated the feasibility of this approach using a 188-rhenium ( (188)Re)-radiolabeled melanin-binding decapeptide to fungal melanin known as 4B4. Although the results indicated that radiolabeled...

BACKGROUND Adaptation is an evolutionary process in which traits in a population are tailored by natural selection to better meet the challenges presented by the local environment. The major discussion relating to natural selection concerns the portraying of the cause and effect relationship between a presumably adaptive trait and selection agents generating it. Therefore, it is necessary to id...

Abstract Melanin is one the most common biological pigments. In humans, specialized cells called melanocytes synthesize pigment from tyrosine and 3,4-dihydroxyphenylalanine via enzyme-catalyzed reactions spontaneous processes. The formed melanin granule consists of nanoaggregates oligomers containing different monomers. Although main function protection against damage solar radiation, may also ...

[Z-W]Thiouracil and [%]thiouracil are incorporated into the melanin of chick retinal pigment epithelium incubated in vitro. This synthesis of a thiouracil pheomelanin (thiolcuntaining melanin) can be used to measure the rate of melanin synthesis in living cells. Thiouracil incorporation is dependent on tyrosinase activity: incorporation is inhibited by phenylthiourea, a tyrosinase inhibitor, an...

Netilmicin, which is mainly used as the sulfate, is a semisynthetic, water soluble aminoglycoside antibiotic obtained by chemical modification of sisomicin. It is active against both Gram-positive and Gram-negative bacteria, including strains which are resistant to other aminoglycosides. Netilmicin form complexes with melanin. The aim of the presented work was to examine the effect of Cu2+, Zn2...

[Z-W]Thiouracil and [%]thiouracil are incorporated into the melanin of chick retinal pigment epithelium incubated in vitro. This synthesis of a thiouracil pheomelanin (thiolcuntaining melanin) can be used to measure the rate of melanin synthesis in living cells. Thiouracil incorporation is dependent on tyrosinase activity: incorporation is inhibited by phenylthiourea, a tyrosinase inhibitor, an...

Three strains among 20 Streptomyces isolates produce a diffusible dark brown pigment on both peptone-yeast extract agar and Streptomyces isolation agar. They also showed the positive reaction towards L-tyrosine substrates. The pigment has been referred to be dark brown water soluble pigment, as melanin. The present study reports antioxidant activity of melanin pigment from Actinomycete (Strepto...