The effect of hydration on the UV absorption coefficient of intact melanosomes

The physical properties of melanosomes have been shown to depend on water content. Herein, the ultraviolet absorption coefficient at = 244 nm for intact bovine choroidal melanosomes is determined from photoemission electron microscopy images recorded as a function of vacuum exposure. The dehydration...

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Bibliographic Details
Published in:Photochemical & photobiological sciences 2012-04, Vol.11 (4), p.687-691
Main Authors: Lin, Erica, Peles, Dana N, Simon, John D
Format: Article
Language:English
Subjects:
Absorption
Animals
Biochemistry
Biomaterials
Cattle
Chemistry
Melanosomes - chemistry
Microscopy, Electron
Physical Chemistry
Plant Sciences
Solvents - chemistry
Ultraviolet Rays
Vacuum
Water - chemistry
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Summary:The physical properties of melanosomes have been shown to depend on water content. Herein, the ultraviolet absorption coefficient at = 244 nm for intact bovine choroidal melanosomes is determined from photoemission electron microscopy images recorded as a function of vacuum exposure. The dehydration of the melanosome under ultra-high vacuum manifests itself by a decrease in the absorption coefficient to about 60% of its initial value, and a concomitant increase in its image brightness. This change in the absorption of the melanosome is consistent with the influence of solvent polarity on the UV absorption coefficient of model systems for the pigment eumelanin, the predominant UV absorber contained in the choroid melanosomes. The extent of hydration influences the ultraviolet absorption cross-section of melanosomes.
ISSN:1474-905X
1474-9092
DOI:10.1039/c2pp05233d