title: Quantitative characterization and comparative study of feather melanosome internal morphology using surface analysis.
abstract: A successful feather development implies in a precise orchestration of cells in the follicle, which culminates in one of the most complex epidermal structures in nature. Melanocytes contribute to the final structure by delivering melanosomes to the barb and barbule cells. Disturbance to the tissue during the feather growth can damage the final structure. Here, melanosomes seen in an unusual outgrowth on the barb cortex of a flight feather are reported and compared to commonly observed melanosomes embedded in the cortex. Transmission Electron Microscopy in scanning-transmission mode (STEM) generated images coupled with secondary electron detection. The two classes of melanosomes were registered on images combining transmitted and secondary electron signals. Image processing allowed surface analyses of roughness and texture of the internal morphology of these organelles. Results showed that the two classes of melanosomes are significantly distinct internally, indicating that different physiological processes up to feather maturation could have occurred. Surface analysis methods are not regularly used in cell biology studies, but here it is shown that it has great potential for microscopic image analysis, which could add robust information to studies of cell biology events.
authors.affiliation: Smithsonian Institution, National Museum of Natural History, Division of Birds, E-600, MRC 116, 10th & Constitution Ave, NW, Washington DC 20560, USA; Universidade Federal do Rio de Janeiro, Instituto de Biofísica Carlos Chagas Filho, Laboratório de Ultraestrutura Celular Hertha Meyer, Ilha do Fundão, Rio de Janeiro, RJ 21949-900, Brazil. Electronic address: StrakerL@si.edu.
authors.forename: Lorian Cobra
authors.initials: LC
authors.lastname: Straker
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001717:Birds / Q000033:anatomy & histology; D004817:Epidermis / Q000033:anatomy & histology; D005241:Feathers / Q000254:growth & development* / Q000502:physiology / Q000648:ultrastructure; D007091:Image Processing, Computer-Assisted; D008544:Melanocytes / Q000648:ultrastructure; D020460:Melanosomes / Q000502:physiology / Q000648:ultrastructure*; D046529:Microscopy, Electron, Transmission; D013499:Surface Properties
keywords: Feather development; Melanosome; Morphology; Storm petrel; Surface analysis; Transmission Electron Microscopy