Elektronenmikroskopische Untersuchungen des Auges von Planarien

Röhlich, P.; Török, Ludwig

doi:10.1007/bf00338790

Cited by 59 publications

(3 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The morphology at the ultrastructural level of turbellarian photoreceptors has been reported for the adults of several groups (Wolken 1958;Press 1959;R6hlich T6r6k 1961;Eakin 1963;Mac Rae 1964Stewart 1966;Kishida 1967;Burt & Phillips 1969;Bedini et al 1973;Bedini & Lanfranchi 1974;Carpenter et al 1974;Durand & Gourbault 1975;Ehlers & Ehlers 1977a, b). The ultrastructure of the eyes of turbellarian larvae has been briefly described by Ruppert (1978) for the polyclads.…”

Section: Methodsmentioning

confidence: 98%

The ultrastructure of the eyes in larval and adult polyclads (Turbellaria)

Lanfranchi¹,

Bedini²,

Ferrero³

1981

Hydrobiologia

View full text Add to dashboard Cite

Examination of the larvae of Thysanozoon brocchii and Stylochus mediterraneus shows that they have both epidermal and cerebral eyes, while the young worms of Notoplana alcinoi have only cerebral eyes. A description is given of the ultrastructure of both kinds of eyes. The epidermal eye consists of one cup-shaped pigmented cell, whose cavity is filled with lamellae of ciliary origin. A small covering cell is located over the cup-opening. The cerebral eye is made up of three cells: one pigmented cell with ciliary projections and two rhabdomeric-type photoreceptor cells. The cerebral eye in the adult is formed of a pigmented cup without cilia and at least three rhabdomeric-type photoreceptors. A number of remarks of a morpho-onthological nature are presented.

show abstract

Section: Methodsmentioning

confidence: 98%

The ultrastructure of the eyes in larval and adult polyclads (Turbellaria)

Lanfranchi¹,

Bedini²,

Ferrero³

1981

Hydrobiologia

View full text Add to dashboard Cite

show abstract

“…The exact meaning of 'compact group of tubules' affects the boundaries of applicability of the term rhabdomere. For example, the photoreceptor microvilli arising from the borders of the visual cells of the planarian Dendrocoelum are irregularly packed and form no single, parallel array (Rohlich & Torok, 1961). Nevertheless, the basic similarity of structure probably justifies the extension of the term rhabdomere to this Biirstensaum.…”

Section: (A) Electron Microscopymentioning

confidence: 99%

Photoreceptor Organelles in Animals

Moody

1964

Biological Reviews

View full text Add to dashboard Cite

Summary 1. The relatively high refractive index of rod and cone outer segments causes them to show wave‐guide properties. 2. Rod outer segments have a positive intrinsic birefringence and a negative form birefringence. The former results from oriented lipid molecules, the latter from the disk structure of the outer segment. 3. Electron microscopy of outer segments shows that the disks are formed from infoldings of the surface membrane, each disk consisting of two folds adhering together on their outer surfaces. Studies of other cell membranes have suggested that their lipid molecules form a continuous or discontinuous bimolecular leaflet which is sandwiched between protein layers, and this structure probably applies to each of the disk membranes. 4. From the lipid content of rod outer segments a rough estimate of the thickness of a continuous lipid layer in each disk membrane can be made. This is only a little smaller than the requirements of a bimolecular leaflet. 5. Rhodopsin is a lipoprotein whose lipid content forms a considerable fraction of the total outer‐segment lipid. This and other data suggest that rhodopsin may be a structural component of the disk membrane. 6. The initial effect of light on rhodopsin is probably to isomerize II‐cis to all‐trans retinene, and various thermal rearrangements follow which eventually cause the detachment of retinene from opsin. The absorption spectrum of rhodopsin is similar in situ and in solution, but the absorption spectra of the photoproducts are somewhat different. 7. Rhodopsin is strongly dichroic in the rod, indicating that the retinene molecule lies mainly in the plane of the disks. 8. Rhabdomeres, the photoreceptor organelles of many higher invertebrates, are formed from close‐packed microvilli. They show a negative birefringence which probably results from the lipid molecules within the microvillar membrane. 9. All well‐authenticated rhabdomere visual pigments have a retinene chromophore, and in many features the photochemical processes resemble those of vertebrate rhodopsin. The extraction processes for vertebrate and invertebrate rhodopsins are also similar. 10. The question of whether insect rhabdomeres show dichroism is still open, but there is good evidence for dichroism in some cephalopod rhabdomeres. This is probably the physiological basis for the polarized light discrimination shown by octopus. 11. Some possible mechanisms for the transmission of the light stimulus within photoreceptor organelles are discussed.

show abstract

“…Plathelminth worms are equipped with photoreceptors diffusely scattered over the whole body as well as with complex organs of sight in the form of ocelli with inverse retinas (WOLKEN, 1958;ROHLICH and TOROK, 1961). Extracellular recordings from planarian ocelli are consistent with a rhodopsinlike photopigment with Amax = 508 nm (BROWN et ai., 1968).…”

Section: Lower Invertebratesmentioning

confidence: 99%

Comparative Physiology and Evolution of Vision in Invertebrates

Autrum¹,

Bennett

Diehn

et al. 1979

Handbook of Sensory Physiology

View full text Add to dashboard Cite

The use of general descriptive namens, trade namcns, trade marks, etc. in this publication, even ifthe former are not especially identified, is not to be taken as a sign that such names, as understood by the Trade Marks and Merchandise Marks Act, may accordingly be used freely by anyone. This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations. broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. Under § 54 of the German Copyright Law where copies are made for other than private use, a fee is payable to the publisher, the amount of the fee to be determined by agreement with the publisher. © by Springer.Verlag, Berlin· Heidelberg 1979. Softcover reprint of the hardcover 1st edition 1979 2122/3120·543210 VI Prefacewhere the relationship between form and function is especially close. In the foreground, then, we shall stress biophysics, biochemistry, and behavior. Nevertheless, the number of species cited as examples is quite large. To guard against premature generalization, the particular species studied is named in all of the following discussions; it is clearly a bad habit to speak simply of "the fly". On the other hand, the available variety of animals should not be used as an excuse for multiplying the already far too numerous publications by repetitious experiments revealing only analogous results. Such studies of related species, if they are to be of interest, must pose new questions of their own-whether the approach employed derives from ecology, behavior, biochemistry, or biophysics. Comparative physiology can of course not be limited to the invertebrates. In many chapters vertebrates are drawn into the discussion, either because they have evolved comparable structures or functions or because they differ. Correspondingly, invertebrates are also treated elsewhere in this handbook, in addition to these two parts of Vol. VII; these articles are listed at the end of the Preface. In all cases, repetition has been avoided wherever possible.Part A is concerned primarily with the physiology of photoreceptor cells. It is impossible to draw a strict boundary between this aspect and the central nervous processes, for various reasons. First there is the obvious fact that photoreception does not stop with the photoreceptors. Second, in invertebrates, far more than in vertebrates, the study of vision has begun with and depends on behavioral experiments; as a rule, the biochemical and biophysical work has stemmed from prior analyses of behavioral physiology. Color vision, sensitivity to polarized and UV light, and extraocular photoreception are examples. Circadian periodicity, which is treated briefly, does not yet enjoy a genuine causal analysis; as such, it is a quite distinct behavioral phenomenon.The attentive reader of the contributions to these volumes will find many unsolved problems; the further research progresses, the further the horizon reced...

show abstract

Elektronenmikroskopische Untersuchungen des Auges von Planarien

Cited by 59 publications

References 14 publications

The ultrastructure of the eyes in larval and adult polyclads (Turbellaria)

The ultrastructure of the eyes in larval and adult polyclads (Turbellaria)

Photoreceptor Organelles in Animals

Comparative Physiology and Evolution of Vision in Invertebrates

Contact Info

Product

Resources

About