Journal article


A combined reflection confocal laser scanning, electron and fluorescence microscopy analysis of the eyespot in zoospores of Vischeria spp. (Eustigmatales, Eustigmatophyceae)


Publication Details
Author(s): Santos L, Melkonian M, Kreimer G
Journal: Phycologia
Publisher: International Phycological Society
Publication year: 1996
Volume: 35
Journal issue: 4
Pages range: 299-307
ISSN: 0031-8884

Abstract

The reflective properties of the extraplastidic eyespot in zoospores of Vischeria spp. (Eustigmatophyceae) were investigated using confocal laser scanning microscopy in the epireflection contrast mode. Appearance and intensity of reflection signals strongly depended on the relative orientation of the eyespot surface toward the incident laser light. Maximal reflection was only observed when the ventral surface of the eyespot, i.e. the surface that faces the button-shaped flagellar swelling, was approximately perpendicular to the light. However, even in these orientations only c. 10-16% of the eyespot area exhibited strong reflection signals. No or only faint reflection signals were detectable when the cells were viewed from the apical or antapical pole or when the eyespot was analysed from the dorsal side. Serial thin sections revealed the location of the flagellar swelling in a depression of the cell surface and complete shielding of its layered, electron-dense material by large D-shaped and smaller carotenoid-rich eyespot lipid globules. The location, dimensions and intensity distribution of the reflection signal obtained in horizontal and vertical optical sections is consistent with the hypothesis that the reflected light is focused by the concave surface of the D-shaped eyespot globule(s). A green autofluorescence from the eyespot/flagellar swelling region was observed upon blue-violet excitation (436 not). No autofluorescence originated from the flagellum proper. A mechanism is proposed for contrast enhancement at the presumed photoreceptor location (flagellar swelling) by the eyespot based on its shading and reflective properties.



How to cite
APA: Santos, L., Melkonian, M., & Kreimer, G. (1996). A combined reflection confocal laser scanning, electron and fluorescence microscopy analysis of the eyespot in zoospores of Vischeria spp. (Eustigmatales, Eustigmatophyceae). Phycologia, 35(4), 299-307. https://dx.doi.org/10.2216/i0031-8884-35-4-299.1

MLA: Santos, L. M. A., Michael Melkonian, and Georg Kreimer. "A combined reflection confocal laser scanning, electron and fluorescence microscopy analysis of the eyespot in zoospores of Vischeria spp. (Eustigmatales, Eustigmatophyceae)." Phycologia 35.4 (1996): 299-307.

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