Melanin, which is responsible for virtually all visible skin, hair, and eye pigmentation in humans, is synthesized, deposited, and distributed in subcellular organelles termed melanosomes. A comprehensive determination of the protein composition of this organelle has been obstructed by the melanin present. Here, we report a novel method of removing melanin that includes in-solution digestion an...

BACKGROUND Malignant melanomas are intrinsically resistant to many conventional treatments, such as radiation and chemotherapy, for reasons that are poorly understood. Here we propose and test a model that explains drug resistance or sensitivity in terms of melanosome dynamics. METHODS The growth and sensitivity to cisplatin of MNT-1 cells, which are melanotic and enriched with mature stage I...

Studies on pigment donation in tissue culture (1-5) indicate that melanosome transfer is a cytophagic process during which a portion of a melanocyte dendrite is pinched off by the epidermal cell so that melanosomes and melanocyte cytoplasm are incorporated into the keratinocyte. At the ultrastructural level, one would ex-rect to see, at this stage, a cluster of melanosomes embedded in a cytopla...

BACKGROUND AND OBJECTIVE Selective photodamage of the retinal pigment epithelium (RPE) is a new technique to treat a variety of retinal diseases without causing adverse effects to surrounding tissues such as the neural retina including the photoreceptors and the choroid. In this study, the mechanism of cell damage after laser irradiation was investigated. STUDY DESIGN/MATERIALS AND METHODS Si...

Melanotic melanoma (MM) of Xiphophorus (Te1eostei: Poeciliidae) was studied by conventional preparations and freeze-etch preparations for electron microscopy. MM of Xiphophorus exhibits tightly packed pigment cells with prominent dendritic processes and interdigitations of their plasma membranes. The most impressive feature of MM cells is the occurrence of Iarge lobulated nuclei with numerous n...

Developmental constraints and trade-offs can limit diversity, but organisms have repeatedly evolved morphological innovations that overcome these limits by expanding the range and functionality of traits. Iridescent colours in birds are commonly produced by melanin-containing organelles (melanosomes) organized into nanostructured arrays within feather barbules. Variation in array type (e.g. mul...

Fish have defense systems that are capable of repairing damages caused by xenobiotics like benzo[a]pyrene (BaP), so the aims this study were to identify BaP toxicity in melanomacrophages (MMs) cytoskeleton, evaluate melanin area MMs, and analyze genotoxicity. Rainbow trout juveniles (n = 24) split 48h 7d treatments received 2 mg/kg BaP. After experiment, blood samples collected liver was remove...

The iridescent plumage of many birds is structurally colored due to an orderly arrangement melanosomes in their feather barbules. Here, we investigated the blue- purple-colored feathers European starling ( Sturnus vulgaris ) and blue green Cape Lamprotornis nitens ). In both cases, barbules contain essentially a single layer melanosomes, but S. they are solid rod-shaped, L. hollow rod- as well ...