Visual Pigments of Invertebrates

Stavenga, Doekele G.; Schwemer, Joachim

doi:10.1007/978-1-4613-2743-1_2

Cited by 57 publications

(30 citation statements)

References 125 publications

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“…Such a green rhodopsin is invariably photointerconvertible with a metarhodopsin state absorbing in the the blue (A max approx. 490 nm; see Stavenga and Schwemer, 1984;Stavenga, 1989 by straylight thus removes this potential noise and possibly this is the second means by which the screening pigment in the DA enhances the contrast sensitivity of the photoreceptor cells. Longwavelength leaky screening pigments seem to be developed in several insect eyes (revs.…”

Section: Discussionmentioning

confidence: 99%

Functional morphology of the divided compound eye of the honeybee drone (Apis mellifera)

1991

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ABSTRACT.Using different approaches, the functional morphology of the compound eye of the honeybee drone was examined. The drone exhibits an extended acute zone in the dorsal part of its eye. The following specializations were found here: enlarged facet diameters; smaller interommatidial angles; red-leaky screening pigment; enlarged rhabdom diameters; photopigment composition different from the drone's ventral eye region and the worker bee's eye. Thus, similar to other male insects, the drone compound eye is divided into a male-specific dorsal part and a ventral part resembling the worker bee's eye. The functional significance of the sex-specific acute zone is discussed with respect to mating behaviour.

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Section: Discussionmentioning

confidence: 99%

Functional morphology of the divided compound eye of the honeybee drone (Apis mellifera)

1991

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“…In the fruitfly, the peak wavelength of both the rhodopsin and metarhodopsin are slightly hypsochromically shifted: R480-M570; in the hoverfly Eristalis this shift is stronger: R460-M550 (Stavenga and Schwemer, 1984).…”

Section: Photochemical Cycle Of Fly Rhodopsinmentioning

confidence: 97%

“…In the rhodopsin state (also called xanthopsin; Vogt, 1989) the chromophore exists in the 11-cis configuration. After photon absorption this transforms into the all-trans isomer, which is followed by a series of thermal decay steps ending in a thermostable metarhodopsin state (reviews Hamdorf, 1979;Stavenga and Schwemer, 1984). The reverse process, reconversion to rhodopsin, occurs after photon absorption by metarhodopsin.…”

Section: Photochemical Cycle Of Fly Rhodopsinmentioning

confidence: 99%

Insect retinal pigments: Spectral characteristics and physiological functions

Stavenga

1995

Progress in Retinal and Eye Research

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“…In order to enable measurements of the rhodopsin content, blowfly photoreceptor membranes were extracted with 4% digitonin in 0.05 M phosphate buffer, pH 6.1. The rhodopsin concentration was estimated from difference spectra obtained by irradiating extracts with blue light, using 72000 M-' cm-' as the molar absorption coefficient of blowfly metarhodopsin [30]. Rhodopsin of frog ROS was bleached by exposing samples for 2 rnin to orange light (Schott OG 550).…”

Section: Irradiation Of Samples and Estimation Of Rhodopsin Contentmentioning

confidence: 99%

Light‐modulated ADP‐ribosylation, protein phosphorylation and protein binding in isolated fly photoreceptor membranes

Bentrop

Paulsen

1986

European Journal of Biochemistry

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Rhodopsin (P, A, , , 480 nm) of blowfly photoreceptors R1-6 is converted by light into a thermally stable metarhodopsin (M, A, , , 565 nm). In isolated blowfly rhabdoms photoconversion of P to M affects bacterial toxin-catalyzed ADP-ribosylation of a 41-kDa protein, activates phosphorylation of opsin and induces the binding of a 48-kDa phosphoprotein to the rhabdomeric membrane.ADP-ribosylation of the 41-kDa protein is catalyzed by cholera toxin and is inhibited by P -+ M conversion. The 41-kDa protein might represent the a-subunit of the G-protein, proposed to be part of the phototransduction mechanism [Blumenfeld, A. et al. (1985) Proc. Nut1 Acad. Sci. USA 82, 7116-71201.P + M conversion leads to phosphorylation of opsin at multiple binding sites: up to 4 mol phosphate are bound/mol M formed. Dephosphorylation of the phosphate binding sites is induced by photoconversion of M to P. High levels of calcium (2 mM) inhibit phosphorylation of M and increase dephosphorylation of P.Protein patterns obtained by sodium dodecyl sulfate gel electrophoresis of irradiated retina membranes show an increased incorporation of label from [y3'P]ATP also into protein bands of 48 kDa, 68 kDa and 200 kDa. Binding studies reveal that in the case of the 48-kDa protein this effect is primarily due to a light-induced binding of the protein to the photoreceptor membrane. The binding of the 48-kDa phosphoprotein is reversible: after M + P conversion the protein becomes extractable by isotonic buffers. These data suggest that in rhabdomeric photoreceptors of invertebrates light-activation of rhodopsin is coupled to an enzyme cascade in a similar way as in the ciliary'photoreceptors of vertebrates, although there may be differences, e. g. in the type of G-protein which mediates between the activated state of metarhodopsin and a signal-amplifying enzyme reaction.In the ciliary photoreceptors of vertebrates it has been shown that a light-triggered enzyme cascade (transducincyclic GMP phosphodiesterase cascade) mediates between photon absorption by rhodopsin and the closing of cation channels in the photoreceptor's plasma membrane [l -71. The mechanism underlying transduction in rhabdomeric photoreceptors of invertebrates is, at the present, not as adequately understood. The first evidence for light-controlled enzyme reactions in rhabdomeric photoreceptors was obtained by studying rhodopsin phosphorylation in cephalopod photoreceptor membranes [8, 91, a light-induced reaction that has been investigated recently in more detail [lo]. Subsequent investigations suggested a transduction mechanism showing similarities to the enzyme cascade operating in vertebrate photoreceptors; squid photoreceptor membranes Correspondence to R. Paulsen, Fakultat fur Biologie, Tierphysiologie, Ruhr-Universitat Bochum, Postfach 10 21 48, D-4630 Bochum, Federal Republic of Germany Abbreviations. GTPase, guanosine triphosphatase; HBS, Hepesbuffered saline; P, rhodopsin; M, metarhodopsin; P-state membranes, >99% P; M-state membranes, 69% of P converted to M; R1-6, pe...

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Visual Pigments of Invertebrates

Cited by 57 publications

References 125 publications

Functional morphology of the divided compound eye of the honeybee drone (Apis mellifera)

Functional morphology of the divided compound eye of the honeybee drone (Apis mellifera)

Insect retinal pigments: Spectral characteristics and physiological functions

Light‐modulated ADP‐ribosylation, protein phosphorylation and protein binding in isolated fly photoreceptor membranes

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