scholarly journals Two visual pigment opsins, one expressed in the dorsal region and another in the dorsal and the ventral regions, of the compound eye of a dragonfly,Sympetrum frequens

1996 ◽  
Vol 2 (3) ◽  
pp. 209-209 ◽  
Author(s):  
Kentaro Arikawa ◽  
Koichi Ozaki ◽  
Takanari Tsuda ◽  
Junko Kitamoto ◽  
Yuji Mishina
Keyword(s):  
Visual Pigment ◽  
Compound Eye ◽  
Dorsal Region ◽  
Sympetrum Frequens

Two visual pigment opsins, one expressed in the dorsal region and another in the dorsal and ventral regions, of the compound eye of a dragonfly,Sympetrum frequens

1995 ◽  
Vol 1 (1) ◽  
pp. 33-39
Author(s):  
Kentaro Arikawa ◽  
Koichi Ozaki ◽  
Takanari Tsuda ◽  
Junko Kitamoto ◽  
Yuji Mishina
Keyword(s):  
Visual Pigment ◽  
Compound Eye ◽  
Dorsal Region ◽  
Sympetrum Frequens

Fine structure of the compound eye of the black fly Simulium vittatum (Diptera: Simuliidae)

1987 ◽  
Vol 65 (6) ◽  
pp. 1454-1469 ◽  
Author(s):  
Gail E. O'Grady ◽  
Susan B. McIver
Keyword(s):  
Fine Structure ◽  
Compound Eye ◽  
Sensory Receptor ◽  
Dorsal Region ◽  
Male And Female ◽  
Simulium Vittatum ◽  
Transmission Electron ◽  
Accessory Pigment ◽  
Open Rhabdom ◽  
Retinular Cells

The fine structure of the ommatidia in light- and dark-adapted eyes of male and female Simulium vittatum Zetterstedt was investigated using scanning and transmission electron microscopy. The male eye is divided into distinct dorsal and ventral regions. The facets in the dorsal region are approximately two times larger than those in the ventral one, which are similar in size to the ones in the female eye. All ommatidia of S. vittatum examined consist of two general regions: a distal dioptric apparatus with bordering primary and accessory pigment and Semper cells, and a sensory receptor layer. Each ommatidium in the female eye and ventral eye of the male has eight retinular cells (R cells): six peripheral (R1–6) and two central (R7, R8). R7 occurs distally and R8 basally. Strikingly, the ommatidia in the dorsal eye of the male lack the R7 cell. In all ommatidia, rhabdomeres on the inner surface of the peripheral R cells are separate throughout their length, creating an open rhabdom. A greater diameter of corneal facets, elongated peripheral R cells, and perhaps the lack of the R7 cell are specializations of the dorsal region of the eye that help the male to detect small, rapidly moving females against the skylight as they fly above the swarm of males. Differences observed between light- and dark-adapted eyes of male and female S. vittatum were the same and were associated with the internal components of the peripheral R cells.

scholarly journals The role of retinal photoisomerase in the visual cycle of the honeybee.

1991 ◽  
Vol 97 (1) ◽  
pp. 143-165 ◽  
Author(s):  
W C Smith ◽  
T H Goldsmith
Keyword(s):  
Visual Pigment ◽  
Compound Eye ◽  
Rod Outer Segments ◽  
Visual Cycle ◽  
In Vitro Techniques ◽  
The Third ◽  
Isomerization Processes

The compound eye of the honeybee has previously been shown to contain a soluble retinal photoisomerase which, in vitro, is able to catalyze stereospecifically the photoconversion of all-trans retinal to 11-cis retinal. In this study we combine in vivo and in vitro techniques to demonstrate how the retinal photoisomerase is involved in the visual cycle, creating 11-cis retinal for the generation of visual pigment. Honeybees have approximately 2.5 pmol/eye of retinal associated with visual pigments, but larger amounts (4-12 pmol/eye) of both retinal and retinol bound to soluble proteins. When bees are dark adapted for 24 h or longer, greater than 80% of the endogenous retinal, mostly in the all-trans configuration, is associated with the retinal photoisomerase. On exposure to blue light the retinal is isomerized to 11-cis, which makes it available to an alcohol dehydrogenase. Most of it is then reduced to 11-cis retinol. The retinol is not esterified and remains associated with a soluble protein, serving as a reservoir of 11-cis retinoid available for renewal of visual pigment. Alternatively, 11-cis retinal can be transferred directly to opsin to regenerate rhodopsin, as shown by synthesis of rhodopsin in bleached frog rod outer segments. This retinaldehyde cycle from the honeybee is the third to be described. It appears very similar to the system in another group of arthropods, flies, and differs from the isomerization processes in vertebrates and cephalopod mollusks.

scholarly journals Electroretinogram Characteristics and the Spectral Mechanisms of the Median Ocellus and the Lateral Eye in Limulus polyphemus

1967 ◽  
Vol 50 (9) ◽  
pp. 2267-2287 ◽  
Author(s):  
Robert M. Chapman ◽  
Abner B. Lall
Keyword(s):  
Spectral Sensitivity ◽  
Visual Pigment ◽  
Light Adaptation ◽  
Compound Eye ◽  
State Level ◽  
Chromatic Adaptation ◽  
Absorption Bands ◽  
Energy Functions ◽  
Lateral Eye ◽  
Median Ocellus

Electrical responses (ERG) to light flashes of various wavelengths and energies were obtained from the dorsal median ocellus and lateral compound eye of Limulus under dark and chromatic light adaptation. Spectral mechanisms were studied by analyzing (a) response waveforms, e.g. response area, rise, and fall times as functions of amplitude, (b) slopes of amplitude-energy functions, and (c) spectral sensitivity functions obtained by the criterion amplitude method. The data for a single spectral mechanism in the lateral eye are (a) response waveforms independent of wavelength, (b) same slope for response-energy functions at all wavelengths, (c) a spectral sensitivity function with a single maximum near 520 mµ, and (d) spectral sensitivity invariance in chromatic adaptation experiments. The data for two spectral mechanisms in the median ocellus are (a) two waveform characteristics depending on wavelength, (b) slopes of response-energy functions steeper for short than for long wavelengths, (c) two spectral sensitivity peaks (360 and 530–535 mµ) when dark-adapted, and (d) selective depression of either spectral sensitivity peak by appropriate chromatic adaptation. The ocellus is 200–320 times more sensitive to UV than to visible light. Both UV and green spectral sensitivity curves agree with Dartnall's nomogram. The hypothesis is favored that the ocellus contains two visual pigments each in a different type of receptor, rather than (a) various absorption bands of a single visual pigment, (b) single visual pigment and a chromatic mask, or (c) fluorescence. With long duration light stimuli a steady-state level followed the transient peak in the ERG from both types of eyes.

Packaging of rhodopsin and porphyropsin in the compound eye of the crayfish

1993 ◽  
Vol 10 (2) ◽  
pp. 193-202 ◽  
Author(s):  
Joel Zeiger ◽  
Timothy H. Goldsmith
Keyword(s):  
Visual Pigment ◽  
Regional Variation ◽  
Compound Eye ◽  
Procambarus Clarkii ◽  
Difference Spectra ◽  
Retinular Cells ◽  
Different Levels

AbstractThe distribution of 3-dehydroretinal (Ral2) in dorsal, middle, and ventral slices of eyes of the crayfish Procambarus clarkii was examined by HPLC. No pronounced differences were found. Similar results were obtained when the eyes were cut into anterior, intermediate, and posterior portions.Dichroic difference spectra were measured in single halves of microvillar layers of isolated rhabdoms and the proportions of rhodopsin (P1) and porphyropsin (P2) estimated by comparison with computer-generated mixtures of these pigments, whose spectra are known from previous work. The fraction of visual pigment that is porphyropsin appears to be uniform throughout individual retinular cells and among the retinular cells of individual rhabdoms, but various substantially among different rhabdoms from the same eye.The interommatidial variation in the amount of P2 greatly exceeds the gross regional variation in Ral2. This means there is an intermingling of ommatidia with different levels of P2. The variability in P2 among ommatidia is not likely to have important implications for the vision of the crayfish but suggests that in the metabolism of retinoids, individual ommatidia are quasi-independent metabolic units. The results are compatible with a single opsin for both crayfish rhodopsin and porphyropsin.

scholarly journals The contribution of a sensitizing pigment to the photosensitivity spectra of fly rhodopsin and metarhodopsin.

1979 ◽  
Vol 73 (5) ◽  
pp. 517-540 ◽  
Author(s):  
B Minke ◽  
K Kirschfeld
Keyword(s):  
Spectral Range ◽  
Visual Pigment ◽  
Compound Eye ◽  
Electrical Potential ◽  
High Sensitivity ◽  
Wavelength Dependence ◽  
Difference Spectrum ◽  
Visible Spectral Range ◽  
Photosensitivity Spectrum ◽  
Sensitizing Pigment

Most of the photoreceptors of the fly compound eye have high sensitivity in the ultraviolet (UV) as well as in the visible spectral range. This UV sensitivity arises from a photostable pigment that acts as a sensitizer for rhodopsin. Because the sensitizing pigment cannot be bleached, the classical determination of the photosensitivity spectrum from measurements of the difference spectrum of the pigment cannot be applied. We therefore used a new method to determine the photosensitivity spectra of rhodopsin and metarhodopsin in the UV spectral range. The method is based on the fact that the invertebrate visual pigment is a bistable one, in which rhodopsin and metarhodopsin are photointerconvertible. The pigment changes were measured by a fast electrical potential, called the M potential, which arises from activation of metarhodopsin. We first established the use of the M potential as a reliable measure of the visual pigment changes in the fly. We then calculated the photosensitivity spectrum of rhodopsin and metarhodopsin by using two kinds of experimentally measured spectra: the relaxation and the photoequilibrium spectra. The relaxation spectrum represents the wavelength dependence of the rate of approach of the pigment molecules to photoequilibrium. This spectrum is the weighted sum of the photosensitivity spectra of rhodopsin and metarhodopsin. The photoequilibrium spectrum measures the fraction of metarhodopsin (or rhodopsin) in photoequilibrium which is reached in the steady state for application of various wavelengths of light. By using this method we found that, although the photosensitivity spectra of rhodopsin and metarhodopsin are very different in the visible, they show strict coincidence in the UV region. This observation indicates that the photostable pigment acts as a sensitizer for both rhodopsin as well as metarhodopsin.

scholarly journals Microspectrophotometry of rhodopsin and metarhodopsin in the moth Galleria.

1975 ◽  
Vol 66 (3) ◽  
pp. 383-404 ◽  
Author(s):  
L J Goldman ◽  
S N Barnes ◽  
T H Goldsmith
Keyword(s):  
Visual Pigment ◽  
Compound Eye ◽  
Isosbestic Point ◽  
Difference Spectra ◽  
Photoreceptor Layer ◽  
Spectral Changes ◽  
Fresh Frozen ◽  
High Concentrations ◽  
Dark Regeneration

Fresh, frozen sections of the photoreceptor layer of the compound eye of the moth Galleria have been examined by microspectrophotometry, using 4 times 8 mum measuring beams that sampled from approximately two to four rhabdoms. The principal visual pigment absorbs maximally at 510 nm (P510), and on irradiation is converted to a thermally stable, pH-insensitive metarhodopsin with lambda max at 484 nm (M484) and a 43% increase in molar extinction coefficient. Subsequently, short wavelength irradiation of the metarhodopsin photoregenerates some P510, but the absence of an isosbestic point the cycle of spectral changes is consistent with the presence of smaller amounts of violet-or ultraviolet-sensitive visual pigment(s) that also are converted to a blue-absorbing metarhodopsin. Difference spectra for both P510 and M484 were measured, using hydroxylamine. The 484-nm metarhodopsin is reversibly converted to a form with lambda max at 363 nm by high concentrations of glycerol. Dark regeneration of rhodopsin in vivo after several minutes exposure of thoroughly dark-adapted animals to full sunlight requires several days.

scholarly journals Heterogenic components of a fast electrical potential in Drosophila compound eye and their relation to visual pigment photoconversion.

1980 ◽  
Vol 75 (4) ◽  
pp. 353-379 ◽  
Author(s):  
R S Stephenson ◽  
W L Pak
Keyword(s):  
Visual Pigment ◽  
Compound Eye ◽  
Electrical Potential ◽  
Receptor Potential ◽  
Positive Component ◽  
Flash Intensity ◽  
Pigment System ◽  
Early Receptor Potential ◽  
Late Receptor Potential ◽  
Visual Mutants

The electroretinogram of the dipteran compound eye in response to an intense flash contains an early, diphasic potential that has been termed the M potential. Both phases of the M potential arise from the photostimulation of metarhodopsin. The early, corneal-negative component, the M1, can be recorded intracellularly in the photoreceptors and has properties similar to the classical early receptor potential (ERP). The M1 is resistant to cold, anaesthesia, and anoxia and has no detectable latency. It depends on flash intensity and metarhodopsin fraction in the manner predicted for a closed, two-state pigment system, and its saturation is shown to correspond to the establishment of a photoequilibrium in the visual pigment. On the other hand, the dominant, corneal-positive component, the M2, does not behave like an ERP. It arises, not in the photoreceptors, but deeper in the retina at the level of the lamina, and resembles the on-transient of the electroretinogram in its reversal depth and sensitivity to cooling or CO2. The on-transient, which is present over a much wider range of stimulus intensity than the M potential, has been shown to arise from neurons in the lamina ganglionaris. Visual mutants in which the on-transient is absent or late are also defective in the M2. It is proposed that the M2 and the on-transient arise from the same or similar groups of second-order neurons, and that the M2 is a fast laminar response to the depolarizing M1 in the photoreceptors, just as the on-transient is a fast laminar response to the depolarizing late receptor potential. Unlike the M1, the M2 is not generally proportional to the amount of metarhodopsin photoconverted, and the M2 amplitude is influenced by factors, such as a steady depolarization of the photoreceptor, which do not affect the M1.

Endogenous Rhythms in the Amounts of 11-cis Retinal in the Compound Eye of Ligia Exotica (Crustacea, Isopoda)

1992 ◽  
Vol 167 (1) ◽  
pp. 39-46 ◽  
Author(s):  
TAKAHIKO HARIYAMA ◽  
YASUO TSUKAHARA
Keyword(s):  
Visual Pigment ◽  
Compound Eye ◽  
Morphological Changes ◽  
Clear Correlation ◽  
Average Amount ◽  
Dark Cycle ◽  
Continuous Darkness ◽  
Endogenous Rhythms ◽  
Retinyl Ester ◽  
Subjective Night

The volume of the rhabdom of Ligia exotica changes diurnally, with the rhythm persisting autogenically in continuous darkness. The morphological changes are accompanied by variations in the amounts of the different chromophores making up the visual pigment. The amount of 11-cis retinal was found to be high at night (26.2±3.5pmol per eye) and low during the day (10.9±2.6pmol per eye) and to display an endogenous rhythm. At dawn and dusk, the amount was 19.1±1.2pmol. This rhythmicity persisted in continuous darkness, although the average amount of 11-cis retinal present gradually increased. In the case of all-trans retinal, changes in the amount were rhythmic in light-dark conditions. The amount of all-trans retinal present in the eye increased shortly after the onset of light and decreased soon after the end of illumination. There was about twice as much 11-cis retinyl ester as 11-cis retinal in the compound eye of Ligia exotica. Rhythmicity in the amount of 11-cis retinyl ester present during the light-dark cycle was observed, but it was opposite in phase to that of 11-cis retinal. Under conditions of continuous darkness a clear rhythm was not apparent: the amount of 11-cis retinyl ester increased not only during the subjective day but also during the following subjective night. Thus, a clear correlation exists between changes in structural organization of the rhabdom and the amounts of 11-cis retinal present. Both show features of a circadian rhythm.

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