Altered levels of trace elements are associated with increased oxidative stress that is eventually responsible for pathologic conditions. Oxidative stress has been proposed to be involved in eye diseases, including cataract formation. We visualized the distribution of metals and other trace elements in the eye of zebrafish embryos by micro X-ray fluorescence (μ-XRF) imaging. Many elements showe...

Mitotic figures were demonstrated in the differentiated melanocytes of normal epidermal and nonepidermal tissues without the presence of external stimuli. These dividine melanocytes were present in human and mouse skin, mouse hair, chick feathers, and embryonic chick retinal pigment epithelium. In normal adult human epidermis, dividing melanocytes, though rare, were found in the nonstimulated...

The mechanisms that lead to variation in human skin and hair color are not fully understood. To better understand the molecular control of skin and hair color variation, we modulated the expression of Tyrosinase (Tyr), which controls the rate-limiting step of melanogenesis, by expressing a single-copy, tetracycline-inducible shRNA against Tyr in mice. Moderate depletion of TYR was sufficient to...

The liver of lower vertebrates produces considerable amounts of molecular oxygen during hypoxia, thus the return to normoxic conditions initially brings on high values of oxygen saturation (sO2) in even venous blood. This temporary hyperoxia triggers the oxidative process of hepatic melanogenesis. In newts rendered hypoxic by forced immersion, after 90 minutes of re-oxygenation sO2 of mixed blo...

Melanosome biogenesis requires successive waves of cargo delivery from endosomes to immature melanosomes, coupled with recycling of the trafficking machinery. Dennis et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201605090) report differential roles for BLOC-1 and BLOC-3 complexes in delivery and recycling of melanosomal biogenetic components, supplying directionality to melanosome m...

~Ihe nature of Langerhans cells is disputed. ~fhey have been considered effete melanocytes (1, 2), postmelanin-synthetic cells (3), melanocyte precursors (4), intraepidermal nerve endings (5, 6), or postdivisional stages of previously melanogenic melanocytes (7). Under the electron microscope, melanocytes and Langerhans cells are distinguished by highly characteristic cytoplasmic or-ganelles: m...

T iny, membrane-bound packets of tinted protein, called melano-somes, dictate the color of human skin. Defi ciencies in melanosome production underlie pigmentation diseases, so it is important to understand how melanosomes are generated. But melanosomes are just one example of a larger family of lyso-some-related organelles, many of which are associated with pathologies when they are functional...

Intracellular ion channels are essential regulators of organellar and cellular function, yet the molecular identity and physiological role of many of these channels remains elusive. In particular, no ion channel has been characterized in melanosomes, organelles that produce and store the major mammalian pigment melanin. Defects in melanosome function cause albinism, characterized by vision and ...