> Anatomy > Cell Component > Melanosomes

Melanosomes

Melanosomes are specialized organelles found in melanocytes that produce and store melanin, the pigment responsible for skin, hair, and eye color.
These organelles play a crucial role in the synthesis, transport, and distribution of melanin, influencing the appearance and protective properties of pigmented tissues.
Researchers utilize advanced techniques, such as AI-driven protocol optimization, to enhance the accuracy and reproducibility of melanosome research, unlocking new insights into this pivotal cellular component.
By locating the best protocols from literature, pre-prions, and patents, scientists can achieve more reliable and informative studies on the structure, function, and regulation of melanosomes, ultimately advancing our understanding of pigmentation and related biological processes.
This concise overview provides a foundational understanding of this important organelle and the cutting-edge methods employed to study it.

Most cited protocols related to «Melanosomes»

Ex Vivo Imaging of Neovascular AMD Tissue

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Publication 2015

4-phenylenediamine Allium cepa ARID1A protein, human Autopsy Blood Vessel Bruch Membrane Buffers Choroid Donors Edema Epoxy Resins Eye Glutaral Immersion Lens, Crystalline Light Lipids Lipofuscin Macula Lutea Melanosomes Microscopy Multimodal Imaging Optic Disk Osmium paraform Pathologic Neovascularization Phosphates Photoreceptor Cells Pigmentation Polybed 812 Radionuclide Imaging Retina Tannins Tissue, Membrane Tissues Tolonium Chloride Woman

Analyzing Cellular Organelle Dynamics

Cilia were immunostained with anti-Arl13b antibody (T. Caspary), and cilia size was determined by dividing the number of Arl13b-positive pixels by the number of nuclei per image. Ciliary levels of Gli2 and IFT88 were determined by immunostaining cells with anti-Gli2 (R&D Systems) or anti-IFT88 (ProteinTech Group) antibodies. Analyses of mitotic spindles and kinetochore-microtubule attachments in fixed cells were performed as described^{26 (link)}, and real-time confocal microscopy was conducted with NIH-3T3 cells stably expressing GFP-tubulin. Melanosome and peroxisome motility studies were conducted as reported^{19 (link),20 (link)}.

Firestone A.J., Weinger J.S., Maldonado M., Barlan K., Langston L.D., O'Donnell M., Gelfand V.I., Kapoor T.M, & Chen J.K. (2012). Small-molecule inhibitors of the AAA+ ATPase motor cytoplasmic dynein. Nature, 484(7392), 125-129.

Publication 2012

Antibodies Antibodies, Anti-Idiotypic Cell-Matrix Junction Cell Nucleus Cells Cilia Eyelashes Kinetochores Melanosomes Microscopy, Confocal Microtubules Mitotic Spindle Apparatus Motility, Cell NIH 3T3 Cells Peroxisome Tubulin

Quantitative Analysis of Melanosome Proteins

Relative quantitation of the distribution of Pmel17 and TRP1, Pmel17 and EEA1, or Pmel17, TRP1, and LAMP1 was performed on double or triple immunogold-labeled cryosections by counting the number of gold particles labeling each protein in each of the defined compartments taken randomly in 30 cell profiles. Melanosome stages were defined by morphology (see Results), lysosomes were defined by morphology and/or dense labeling for LAMP1, and early endosomes were defined as tubulovesicular structures labeling densely for EEA1. Results are presented as a percentage of the total number of gold particles for each protein in each compartment and represent a mean and standard deviation of two independent experiments.

Raposo G., Tenza D., Murphy D.M., Berson J.F, & Marks M.S. (2001). Distinct Protein Sorting and Localization to Premelanosomes, Melanosomes, and Lysosomes in Pigmented Melanocytic Cells✪. The Journal of Cell Biology, 152(4), 809-824.

Publication 2001

Cells Cryoultramicrotomy Endocytic Vesicles Gold lysosomal-associated membrane protein 1, human Lysosomes Melanosomes Proteins SILV protein, human tyrosinase-related protein-1

Quantitative Retinal Histopathology Protocol

Population-based eye pathology is made possible by a 25-year collaboration with the Alabama Eye Bank, which has high volume for transplantable tissues and the fastest tissue recovery time among US eye banks. Between 1996 and 2010, our laboratory accessioned >900 pairs of nondiabetic donor eyes within 4 hours (before 2001) or 6 hours (after 2001) of death. In 2010, federal and private funding enabled creation of the Project MACULA Web site as a resource for clinical imaging, using 142 maculas (53 advanced AMD, 13 GA eyes from 12 donors and 40 neovascular AMD eyes from 40 donors; 29 early AMD; 60 age-matched control eyes). Prior to histology, all eyes were subjected to ex vivo imaging including color fundus photography using a dissecting microscope with epi- and oblique transillumination, and SDOCT using a custom tissue holder for a Spectralis HRA+OCT (Heidelberg Engineering, Heidelberg, Germany).^{12 (link)} This holder holds a donor eye lacking an anterior segment, so that the fundus looks horizontally into the instrument through a 60-diopter lens, thus emulating clinical imaging. Tracking from scans obtained during a donor's lifetime can be used to align macular specimens after death. Thus, SDOCT has become essential for the pathology laboratory.
Because contemporary SDOCT provides exquisite structural detail, clinical interpretation is best served by morphologic descriptions that are comprehensive, quantitative, pegged to precise retinal locations, and digitally available. Thus, we sought views that were high magnification, high resolution, color, and panoramic, with the original histology accessible online. Transmission electron microscopy, a comprehensive visualization technique, reveals all organelles including spindle-shaped melanosomes unique to RPE. Submicrometer-thick sections of epoxy resin blocks can emulate the benefits of low-magnification color electron microscopy over wide tissue samples. Postfixation with osmium tannic acid paraphenylenediamine (OTAP) preserves extracellular lipids^{59 (link)–62 (link, link, link)} and imparts polychromaticity to toluidine blue–stained sections. We surveyed standard locations in superior and central macula (through rod ring and foveola, respectively).^{24 (link)} At 25 locations in central sections and 13 locations in superior sections (1050 locations per eye; >150,000 total for all eyes), 21 chorioretinal layers were measured and RPE morphology was annotated with a custom ImageJ (https://fiji.sc/; in the public domain) drop-down menu. Systematic sampling enabled unbiased estimates of phenotype frequency.

Curcio C.A., Zanzottera E.C., Ach T., Balaratnasingam C, & Freund K.B. (2017). Activated Retinal Pigment Epithelium, an Optical Coherence Tomography Biomarker for Progression in Age-Related Macular Degeneration. Investigative Ophthalmology & Visual Science, 58(6), BIO211-BIO226.

Publication 2017

4-phenylenediamine Donors Electron Microscopy Epoxy Resins Eye Lens, Crystalline Macula Lutea Melanosomes Microscopy Organelles Osmium Pathologic Neovascularization Phenotype Public Domain Radionuclide Imaging Retina Tannins Tissue Donors Tissue Engineering Tissues Tolonium Chloride Transillumination Transmission Electron Microscopy

Imaging Techniques for Pigment Analysis

Adult fish were briefly anaesthetised with 0.004% MS-222 (Sigma) and imaged with Canon D5MarkII/MACRO 100 (Figs 1, 3). Fish fixed in 4% paraformaldehyde/0.08% glutaraldehyde (Sigma) (Fig. 2) were photographed under a Leica MZ1 stereomicroscope. Metamorphic fish were anaesthetised, embedded in low melting point agarose with 4.5 mg/ml ± epinephrine (Sigma) for melanosome contraction, and photographed under a Leica M205 FA stereomicroscope with a Leica DCF300 FX camera using the software LAS V4.1 to allow multifocus images. An illumination was chosen to display iridophores optimally while xanthophore visibility is poor. Photographs were processed in Adobe Photoshop.

Frohnhöfer H.G., Krauss J., Maischein H.M, & Nüsslein-Volhard C. (2013). Iridophores and their interactions with other chromatophores are required for stripe formation in zebrafish. Development (Cambridge, England), 140(14), 2997-3007.

Publication 2013

Adult Epinephrine Fishes Glutaral Light Melanosomes MS-222 paraform Sepharose

Most recents protocols related to «Melanosomes»

Comparative Analysis of Melanosomes and Myo7a

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Publication 2023

Hematologic Tests Human Body Melanosomes Mice, House Mood neuro-oncological ventral antigen 2, human Urinalysis

Melanin Quantification in Pigmented Retina

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Publication 2023

araldite Cornea Electron Microscopy Eye Gene, THRA Glutaral Light Microscopy Melanosomes Mice, House paraform Retina Tolonium Chloride Ultramicrotomy

Quantifying Iridescent Feather Nanostructures

To understand the morphological (nanostructural) traits underlying divergence in iridescent coloration, we used a transmission electron microscope (TEM; see below) to image cross-sections of three to five iridescent feather barbules from three body regions (crown, gorget and tail) per single individual of each parental species and the hybrid, following the protocol developed by Shawkey et al. [29 (link)]. Briefly, we dissected iridescent feather barbs, dehydrated them in ethanol, infiltrated the feathers with Embed 812 resin, and cured them at 60°F. We then sectioned the polymerized blocks into approximately 90 nm sections and imaged them on a Philips CM200 TEM at the Beckman Institute for Advanced Science and Technology at the University of Illinois at Urbana-Champaign. On each TEM image, we measured several traits known to be involved in iridescent colour production [17 (link)]: (i) melanosome platelet thickness (pt), (ii) amount of keratin between melanosomes (ker), (iii) air space diameter (air), (iv) number of melanosome layers, (v) thickness of top surficial melanosomes (pt_top), and (vi) keratin cortex thickness (cortex). For air space diameter, we took measurements both parallel (air_par) and perpendicular to the feather barbule surface (air_perp). This was done to determine whether deformation had occurred during sectioning (e.g. the resin often ‘pulls away’ from the outer barbule surface resulting in perpendicular deformation). We made the assumption that air spaces should be roughly isometric in cross-section, thus we took the average of perpendicular and parallel measurements. In total, we took 2421 individual measurements from 33 TEM images (9–13 images per taxon).

Eliason C.M., Cooper J.C., Hackett S.J., Zahnle E., Pequeño Saco T.Z., Maddox J.D., Hains T., Hauber M.E, & Bates J.M. (2023). Interspecific hybridization explains rapid gorget colour divergence in Heliodoxa hummingbirds (Aves: Trochilidae). Royal Society Open Science, 10(3), 221603.

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Publication 2023

Blood Platelets Body Regions Cortex, Cerebral Cytokeratin Ethanol Feathers Hybrids Iridescence Maritally Unattached Melanosomes Parent Resins, Plant Tail Transmission Electron Microscopy

Modeling Feather Nanostructure Reflectance

Following previous work [17 (link)], we used a one-dimensional optical model to simulate reflectance. The model first creates vertical ‘slices’ of the feather nanostructure, all with a uniform refractive index, and then calculates light reflection as a function of wavelength at each interface using a transfer matrix approach [30 (link)]. Given that slight nanostructural variation within or among feather barbules can result in large colour differences [31 (link)], we modelled reflectance spectra using the average nanostructural parameters for each feather TEM image rather than the mean value for an individual. In previous work, we modelled reflectance spectra assuming spherical air spaces within melanosomes [17 (link)]. However, given the more rectangular shape observed in the Heliodoxa species analysed here (electronic supplementary material, figure S1), we also modelled reflectance spectra assuming block-shaped air spaces [32 (link)]. For all models, we used empirical values for the wavelength-dependent refractive indices of eumelanin [33 (link)] and keratin [34 (link)].

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Publication 2023

Cytokeratin eumelanin Feathers Light Melanosomes Reflex

Multipigment Tissue-Mimicking Phantoms

A common modality that uses the optical properties of tissue at multiple spectral bands is the determination of tissue hemoglobin oxygen saturation (

{StO}_{2}

). By measuring the absorption coefficient at two or more wavelengths, tissue chromophore concentrations, namely oxy- and deoxyhemoglobin, can be estimated by solving a series of equations.³⁷ (link)

^–

⁴⁰ (link, link, link) This reliance on multiple wavelengths has made using inorganic phantoms to accurately emulate tissue chromophores difficult. As such, we wanted to determine if the multipigment approach could create phantoms that accurately emulate physiological chromophore concentrations given different levels of

{StO}_{2}

.
To accomplish this, a computational model of skin absorption was made using blood, melanin, water, and fat as the primary chromophores. The absorption coefficient spectrum of the theoretical skin was determined through a summation of the absorption coefficients of the pure chromophores, obtained from the literature, such that

μ_{a} (λ) = {StO}_{2} B H μ_{a}^{{HbO}_{2}} (λ) + (1 - {StO}_{2}) B H μ_{a}^{Hb} (λ) + W μ_{a}^{water} (λ) + F μ_{a}^{fat} (λ) + M μ_{a}^{mel} (λ),

where

H

is the concentration of hemoglobin within blood,

{StO}_{2}

is the ratio of oxyhemoglobin to total hemoglobin, and

B

W

F

, and

M

are the volume fractions of blood, water, fat, and melanosomes, respectively, within the tissue.⁴¹

^–

⁴⁵ (link, link, link, link)
Using fixed volume fractions, tissue absorption spectra were produced between 470 and 950 nm using three different values for

{StO}_{2}

: 30%, 50%, and 80%. The volume fractions for water and fat were set to 0.5 and 0.02, respectively, based on the values used in similar models.³⁸ (link)^,³⁹ (link) A low melanosome volume fraction of 0.0255% was selected so that the theoretical tissue would have an absorption spectrum representative of pale, minimally pigmented skin.⁴⁴ (link)

^–

⁴⁷ (link, link, link) The volume fraction of total blood was set to be 0.047 which, given a blood hemoglobin concentration of

2.3 mmol / L

, corresponded to a total hemoglobin concentration of

110 μ M

, which falls within reported physiological ranges.³⁷ (link)^,³⁹ (link) Although not as important for

{StO}_{2}

measurements, the reduced scattering coefficient of the tissue model was set to be similar to be similar to that of skin. This was accomplished through a Mie-Rayleigh power law equation with values derived from the literature.⁴⁴ (link)^,⁴⁷ (link)
Multipigment phantoms were made to match the theoretical absorption coefficients for each of the three

{StO}_{2}

values using 38 g of total epoxy. The required pigment concentrations (see Table S3 in the Supplementary Material) were determined using the previously described [Eq. (3)] weighted-band approach with bands at 540 to 560 nm, 625 to 645 nm, and 820 to 840 nm, which correspond to wavelength regions often used to measure

{StO}_{2}

in tissue.³⁹ (link)^,⁴⁰ (link) After measuring the optical properties of the oxygenation phantoms, the absorption coefficients at the three bands were used along with Eq. (5) to set up a system of equations to solve for the equivalent melanosome volume fraction, blood volume fraction, and

{StO}_{2}

, assuming a water volume fraction of 0.5 and fat volume fraction of 0.02.

Walter A.B, & Jansen E.D. (2023). Development of a platform for broadband, spectra-fitted, tissue optical phantoms. Journal of Biomedical Optics, 28(2), 025001.

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Publication 2023

BLOOD Blood Volume Cell Respiration deoxyhemoglobin Epoxy Resins Hemoglobin Hemoglobin A Melanins Melanosomes Oximetry Oxygen Oxygen Saturation Oxyhemoglobin physiology Reliance resin cement Skin Skin Absorption Skin Pigmentation Tissues Vision

Top products related to «Melanosomes»

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Ckx41 culture microscope by Olympus

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More about "Melanosomes"

Melanosomes are specialized pigment-producing organelles found within melanocytes, the pigment-producing cells in the body.
These organelles play a crucial role in the synthesis, transport, and distribution of melanin, the pigment responsible for skin, hair, and eye color.
Researchers utilize advanced techniques, such as AI-driven protocol optimization, to enhance the accuracy and reproducibility of melanosome research, unlocking new insights into this pivotal cellular component.
By locating the best protocols from literature, pre-prints, and patents, scientists can achieve more reliable and informative studies on the melanosome structure, function, and regulation, ultimately advancing our understanding of pigmentation and related biological processes.
Epinephrine, a hormone involved in pigmentation, and CKX41 culture microscopes, which are used to visualize melanosomes, are some of the tools and techniques employed in this research.
RPMI 1640 medium, a common cell culture medium, and HMB45, an antibody used to identify melanosomes, are also utilized in melanosome studies.
Entellan, a mounting medium, and M205 FA, a fluorescence microscope, are additional tools that aid in the visualization and analysis of these organelles.
Proteinase K, an enzyme used for protein extraction, and the JEM-1200EX transmission electron microscope, which provides high-resolution imaging of melanosomes, are also important in melanosome research.
By incorporating these techniques and technologies, researchers can achieve more reproducible and informative studies on the structure, function, and regulation of melanosomes, ultimately advancing our understanding of pigmentation and related biological processes.