Scanning transmission X-ray microscopic analysis of purified melanosomes of the mouse iris

Michael G. Anderson; Tamás Haraszti; Greg E. Petersen; Sue Wirick; Chris Jacobsen; Simon W M John; Michael Grunze

doi:10.1016/j.micron.2006.03.008

Scanning transmission X-ray microscopic analysis of purified melanosomes of the mouse iris

Michael G. Anderson^*, Tamás Haraszti, Greg E. Petersen, Sue Wirick, Chris Jacobsen, Simon W M John, Michael Grunze

^*Corresponding author for this work

Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

9 Scopus citations

Abstract

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.

Original language	English (US)
Pages (from-to)	689-698
Number of pages	10
Journal	Micron
Volume	37
Issue number	8
DOIs	https://doi.org/10.1016/j.micron.2006.03.008
State	Published - Dec 2006

Funding

We thank Holger Fleckenstein and Randy Nessler for technical assistance with sample preparation; Peter Guttman and Gerd Schneider for helpful discussions; Janos Kirz for support of the X1A beamline at the National Synchrotron Light Source (NSLS) where these experiments were conducted; Joachim Spatz for providing laboratory and financial support, and the EU STREP NANOCUES for partial financial support. The NSLS is supported by the US Department of Energy, Office of Basic Energy Science, Divisions of Materials Science and Chemical Sciences (DE-AC02-76CH00016). These experiments were initiated and supported by the National Science Foundation/EPSCoR under Grant no. 0132384. SWMJ is an Investigator of The Howard Hughes Medical Institute.

Keywords

Mammalian genetics
Melanin
NEXAFS
Organelle structure-function
Synchrotron radiation

ASJC Scopus subject areas

Structural Biology
Cell Biology

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10.1016/j.micron.2006.03.008

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@article{5dbf6d10a9f24686abe3586632eba699,

title = "Scanning transmission X-ray microscopic analysis of purified melanosomes of the mouse iris",

abstract = "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.",

keywords = "Mammalian genetics, Melanin, NEXAFS, Organelle structure-function, Synchrotron radiation",

author = "Anderson, \{Michael G.\} and Tam{\'a}s Haraszti and Petersen, \{Greg E.\} and Sue Wirick and Chris Jacobsen and John, \{Simon W M\} and Michael Grunze",

note = "Funding Information: We thank Holger Fleckenstein and Randy Nessler for technical assistance with sample preparation; Peter Guttman and Gerd Schneider for helpful discussions; Janos Kirz for support of the X1A beamline at the National Synchrotron Light Source (NSLS) where these experiments were conducted; Joachim Spatz for providing laboratory and financial support, and the EU STREP NANOCUES for partial financial support. The NSLS is supported by the US Department of Energy, Office of Basic Energy Science, Divisions of Materials Science and Chemical Sciences (DE-AC02-76CH00016). These experiments were initiated and supported by the National Science Foundation/EPSCoR under Grant no. 0132384. SWMJ is an Investigator of The Howard Hughes Medical Institute.",

year = "2006",

month = dec,

doi = "10.1016/j.micron.2006.03.008",

language = "English (US)",

volume = "37",

pages = "689--698",

journal = "Micron",

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T1 - Scanning transmission X-ray microscopic analysis of purified melanosomes of the mouse iris

AU - Anderson, Michael G.

AU - Haraszti, Tamás

AU - Petersen, Greg E.

AU - Wirick, Sue

AU - Jacobsen, Chris

AU - John, Simon W M

AU - Grunze, Michael

N1 - Funding Information: We thank Holger Fleckenstein and Randy Nessler for technical assistance with sample preparation; Peter Guttman and Gerd Schneider for helpful discussions; Janos Kirz for support of the X1A beamline at the National Synchrotron Light Source (NSLS) where these experiments were conducted; Joachim Spatz for providing laboratory and financial support, and the EU STREP NANOCUES for partial financial support. The NSLS is supported by the US Department of Energy, Office of Basic Energy Science, Divisions of Materials Science and Chemical Sciences (DE-AC02-76CH00016). These experiments were initiated and supported by the National Science Foundation/EPSCoR under Grant no. 0132384. SWMJ is an Investigator of The Howard Hughes Medical Institute.

PY - 2006/12

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N2 - 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.

AB - 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.

KW - Mammalian genetics

KW - Melanin

KW - NEXAFS

KW - Organelle structure-function

KW - Synchrotron radiation

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AN - SCOPUS:33746867913

SN - 0968-4328

VL - 37

SP - 689

EP - 698

JO - Micron

JF - Micron

IS - 8

ER -

Scanning transmission X-ray microscopic analysis of purified melanosomes of the mouse iris

Abstract

Funding

Keywords

ASJC Scopus subject areas

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