color and plays an important role in the prevention of suninduced skin injury. Melanin biosynthesis proceeds through a complex series of enzymatic and chemical reactions in melanocytes. Synthesis of melanin starts from the conversion of the amino acid L-tyrosine to dopaquinone by tyrosinase, the enzyme catalyzing the rate-limiting step for melanin biosynthesis. This tyrosinase process is involv...

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...

BACKGROUND Lomefloxacin is a potent bactericidal antibiotic. The use of this drug in treatment of various infections is accompanied by serious adverse effects on pigmented tissues. The exact mechanisms of lomefloxacin side effects have not been well established yet. The aim of this study was to characterize the interaction between lomefloxacin and melanin, and to examine how this interaction af...

Skin cells from albino mouse embryos have been shown to synthesize melanin after exposure to a nucleoprotein fraction of cells from pigmented mice. Although transformed clones were not found in any of 37 control experiments, at least 15 transformations took place in 10 of a series of 49 experiments using undegraded DNA. The active component in the transforming material appears to be DNA because...

Melanocytes are cells specialized in the synthesis of the pigment melanin, in the form of eumelanin, the brown/black, and pheomelanin, the red/yellow pigment (Ito and Wakamatsu 2003). Melanocytes reside in the cutaneous epidermis, within hair follicles, in the eye, the leptomeninges, the inner ear, and as has been demonstrated lately, in the heart (Brito and Kos 2008; Goldgeier et al. 1984; Tac...

Melanogenesis is the process of generating pigmentation via melanin synthesis and delivery. Three key enzymes, tyrosinase, tyrosinase-related protein 1 (TRP1) and TRP2, metabolize melanin from L-tyrosine. Melanin synthesizing enzymes are regulated by microphthalmia-associated transcription factor (MITF). The titrated extract of Centella asiatica (TECA) contains the major components asiatic acid...

Protecting human skin from sun exposure is a complex issue that involves unclear aspects of the interaction between light and tissue. A persistent misconception is that visible light is safe for the skin, although several lines of evidence suggest otherwise. Here, we show that visible light can damage melanocytes through melanin photosensitization and singlet oxygen (1O2) generation, thus decre...

Melanosomes are lysosome-related organelles with specialized capabilities of melanin synthesis and movement mediated by the Rab27a-Melanophilin-MyosinVa protein complex. In this study, we found that 2-methyl-naphtho[1,2,3-de]quinolin-8-one (MNQO) induced melanosome aggregation around the nucleus in melan-a melanocytes and in melan-a melanocytes/SP-1 keratinocyte co-cultures without inducing tox...

Skin intrinsic fluorescence is associated with hemoglobin A 1c and hemoglobin glycation index but not mean blood glucose in children with type 1 diabetes. In the print version of the article listed above, on page 1817, the sentence " For the second k x /k m set (set c), k x and k m were 0.5 and 0, respectively, which is useful for populations with a wide range of skin melanin (17) (further tech...

Melanin content (percentage by weight) was determined in both pigmented and nonpigmented tissues of Syrian golden hamsters bearing Greene melanoma. Melanin content was also measured in various other melanoma models (B-16 in C57 mice, Harding-Passey in BALB/c mice, and KHDD in C3H mice) and in nine human melanomas, as well as in selected normal tissues. The purpose was to evaluate the possible e...