Scanning Tranmission X-ray Microscopic Analysis of Purifed Melanosomes of the Mouse Iris

Journal Article · Sun Jan 01 04:00:00 EST 2006 · Micron

DOI:https://doi.org/10.1016/j.micron.2006.03.008· OSTI ID:913983

Anderson, M; Haraszti, T; Peterson, G; Wirick, S; Jacobsen, C; John, S; Grunze, M

Melanosomes are specialized intracellular membrane bound organelles that produce and store melanin pigment. The composition of melanin and distribution of melanosomes determine the color of many mammalian tissues, including the hair, skin, and iris. However, the presence of melanosomes within a tissue carries potentially detrimental risks related to the cytotoxic indole-quinone intermediates produced during melanin synthesis. In order to study melanosomal molecules, including melanin and melanin-related intermediates, we have refined methods allowing spectromicroscopic analysis of purified melanosomes using scanning transmission X-ray microscopy. Here, we present for the first time absorption data for melanosomes at the carbon absorption edge ranging from 284 to 290 eV. High-resolution images of melanosomes at discrete energies demonstrate that fully melanized mature melanosomes are internally non-homogeneous, suggesting the presence of an organized internal sub-structure. Spectra of purified melanosomes are complex, partially described by a predominating absorption band at 288.4 eV with additional contributions from several minor bands. Differences in these spectra were detectable between samples from two strains of inbred mice known to harbor genetically determined melanosomal differences, DBA/2J and C57BL/6J, and are likely to represent signatures arising from biologically relevant and tractable phenomena.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 913983
• Report Number(s): BNL--78551-2007-JA
• Journal Information: Micron, Journal Name: Micron Journal Issue: 8 Vol. 37; ISSN 0047-7206; ISSN MICOB5
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ABSORPTION
CARBON
CELL CONSTITUENTS
COLOR
DISTRIBUTION
HAIR
MELANIN
MEMBRANES
MICE
MICROSCOPY
NSLS
SPECTRA
STRAINS
SYNTHESIS
national synchrotron light source