Book/Report

FZJ-2018-01565

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Ultrastrukturuntersuchungen an der Retina des Flußkrebses Astacus Leptodactylus mit Hilfe der Gefrierbruch - und Ultradünnschnitt-Methode

Winterhager, E. (Corresponding author)FZJ*

1981
Kernforschungsanlage Jülich, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/17537

Report No.: Juel-1701

Abstract: Ultrastructural changes of the microvilli of the Astacus retina depending on the state of light adaptation were investigated by electron microscopy of replicas of freeze fracture faces. (1) The particles on the plasmatic fracture face (PF) of the microvillus membrane, most of which being identical with rhodopsin, are distributed statistically in the state of dark adaptation. Upon light adaptation ( $\geq$ 24 h with 70 $\mu$W cm$^{-2}$ or $\geq$ 3 h with 1-2 mW cm$^{-2}$) the particles become orientated in certain areas in a helical structure of rows (periodicity of 11 nm) around the microvillus. As shown by sprayfreezed unf ixed rhabdoms of light adapted eyes of Astacus these structures are not artef acts caused by glutaraldehyde or glycerol. As the f ormation of these rows depends on duration and intensity of the adapting light it seems to be correlated with light-induced processes in the receptor. (2) Addition of cycloheximide prevents the formation of rows of the particles during light adaptation, which might suggest a relation with protein synthesis. (3) The structured areas could possibly represent rows of metarhodopsin molecules. (4) The packing density of the particles of dark adapted retinae is found to be as great as 5000 ± 600 per $\mu$m$^{2}$ membrane area , that of lightadapted retinae as is enriched in the great as 7000 $\pm$ 1400 $\mu$m$^{-2}$ , and structured areas to 11000 $\pm$ 1000 $\mu$m$^{-2}$. The mean diameter of the particles is 80 $\mathring{A}$. (5) Under high vacuum conditions (UHV) most of the particles of the microvillus membrane are 40-50 $\mathring{A}$ in diameter,which agrees with the theoretically expected value of rhodopsin. (6) Illumination with light of higher intensity causes, in addition to the normal light-inducedstructural changes of the photoreceptor membrane, the formation of myelin-like membrane complexes, which leads to the destruction of the photoreceptor.

---

Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

---

Database coverage:

---