11-cis retinal restores visual function in vitamin A-deficient Manduca

1991 ◽  
Vol 6 (5) ◽  
pp. 473-479 ◽  
Author(s):  
Ruth R. Bennett ◽  
Richard H. White
Keyword(s):  
Visual Function ◽  
Dark Adaptation ◽  
High Performance ◽  
Light Adaptation ◽  
Head Capsule ◽  
Visual Sensitivity ◽  
Compound Eyes ◽  
Deficient Diet ◽  
Photoreceptor Membranes ◽  
Cis Isomer

AbstractLarvae of the tobacco hornworm moth Manduca sexta were reared on either a carotenoid-supplemented or a carotenoid-deficient diet. The former yields fortified adults with normal visual function, whereas visual sensitivity and rhodopsin content are reduced by 2−4 log units in the compound eyes of the deprived moths reared on the latter. We characterized the retinoids of fortified retinas and investigated the recovery of visual function in deprived moths that were provided with retinaldehyde as a source of photopigment chromophore. Retinoids were identified and measured by high-performance liquid chromatography (HPLC). Fortified retinas contained mainly 3-hydroxyretinaldehyde (R3); 11-cis R3 predominated in dark-adaptation, all-trans in light-adaptation, indicating that R3 is the photopigment chromophore. No retinoids could be measured in deprived eyes. Retinaldehyde (R1) was delivered to the retinas of deprived moths by “painting” solutions of 11-cis or all-trans R1 in dimethylsulfoxide (DMSO) on the corneal surfaces of the compound eyes or on the head capsule between the eyes. 11-cis R1 induced rapid recovery: during 3 days, sensitivity rose to within a log unit of that measured from fortified animals. By 7 days, sensitivity was close to normal. Although rhodopsin and P-face particle densities of photoreceptor membranes increased, neither rose to the levels found in fortified animals. All-trans R1 induced only a slight increase in sensitivity that could have resulted from some nonspecific isomerization of the all-trans to the 11-cis isomer; we found no evidence for a retinal isomerase that functions in darkness. Small amounts of R3 were measured in recovering retinas, indicating some conversion of R1 to R3. However, the chromophore of most of the rhodopsin that was synthesized must have been R1. It is possible that rhodopsin did not reach normal levels in the retina even after a week of recovery because the normal chromophore R3 was not provided. Although the rhodopsin that initially formed in recovering moths may have resulted from the association of the chromophore with pre-existing opsin, the extent of eventual recovery indicates that opsin synthesis was stimulated by 11-cis R1.

scholarly journals IODOPSIN

1955 ◽  
Vol 38 (5) ◽  
pp. 623-681 ◽  
Author(s):  
George Wald ◽  
Paul K. Brown ◽  
Patricia H. Smith
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Dark Adaptation ◽  
Visual Sensitivity ◽  
High Threshold ◽  
Scotopic Sensitivity ◽  
Rods And Cones ◽  
Near Ultraviolet ◽  
Spontaneous Reaction ◽  
Cis Isomer

The iodopsin system found in the cones of the chicken retina is identical with the rhodopsin system in its carotenoids. It differs only in the protein—the opsin —with which carotenoid combines. The cone protein may be called photopsin to distinguish it from the scotopsins of the rods. Iodopsin bleaches in the light to a mixture of photopsin and all-trans retinene. The latter is reduced by alcohol dehydrogenase and cozymase to all-trans vitamin A1. Iodopsin is resynthesized from photopsin and a cis isomer of vitamin A, neovitamin Ab or the corresponding neoretinene b, the same isomer that forms rhodopsin. The synthesis of iodopsin from photopsin and neoretinene b is a spontaneous reaction. A second cis retinene, isoretinene a, forms iso-iodopsin (λmax 510 mµ). The bleaching of iodopsin in moderate light is a first-order reaction (Bliss). The synthesis of iodopsin from neoretinene b and opsin is second-order, like that of rhodopsin, but is very much more rapid. At 10°C. the velocity constant for iodopsin synthesis is 527 times that for rhodopsin synthesis. Whereas rhodopsin is reasonably stable in solution from pH 4–9, iodopsin is stable only at pH 5–7, and decays rapidly at more acid or alkaline reactions. The sulfhydryl poison, p-chloromercuribenzoate, blocks the synthesis of iodopsin, as of rhodopsin. It also bleaches iodopsin in concentrations which do not attack rhodopsin. Hydroxylamine also bleaches iodopsin, yet does not poison its synthesis. Hydroxylamine acts by competing with the opsins for retinene. It competes successfully with chicken, cattle, or frog scotopsin, and hence blocks rhodopsin synthesis; but it is less efficient than photopsin in trapping retinene, and hence does not block iodopsin synthesis. Though iodopsin has not yet been prepared in pure form, its absorption spectrum has been computed by two independent procedures. This exhibits an α-band with λmax 562 mµ, a minimum at about 435 mµ, and a small ß-band in the near ultraviolet at about 370 mµ. The low concentration of iodopsin in the cones explains to a first approximation their high threshold, and hence their status as organs of daylight vision. The relatively rapid synthesis of iodopsin compared with rhodopsin parallels the relatively rapid dark adaptation of cones compared with rods. A theoretical relation is derived which links the logarithm of the visual sensitivity with the concentration of visual pigment in the rods and cones. Plotted in these terms, the course of rod and cone dark adaptation resembles closely the synthesis of rhodopsin and iodopsin in solution. The spectral sensitivities of rod and cone vision, and hence the Purkinje phenomenon, have their source in the absorption spectra of rhodopsin and iodopsin. In the chicken, for which only rough spectral sensitivity measurements are available, this relation can be demonstrated only approximately. In the pigeon the scotopic sensitivity matches the spectrum of rhodopsin; but the photopic sensitivity is displaced toward the red, largely or wholly through the filtering action of the colored oil globules in the pigeon cones. In cats, guinea pigs, snakes, and frogs, in which no such colored ocular structures intervene, the scotopic and photopic sensitivities match quantitatively the absorption spectra of rhodopsin and iodopsin. In man the scotopic sensitivity matches the absorption spectrum of rhodopsin; but the photopic sensitivity, when not distorted by the yellow pigmentations of the lens and macula lutea, lies at shorter wave lengths than iodopsin. This discrepancy is expected, for the human photopic sensitivity represents a composite of at least three classes of cone concerned with color vision.

Perylene and perinone pigments

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Robert Christie ◽  
Adrian Abel
Keyword(s):  
High Performance ◽  
Heat Stability ◽  
High Heat ◽  
Structural Features ◽  
Fastness Properties ◽  
Tetracarboxylic Acid ◽  
Organic Pigments ◽  
Orange Color ◽  
Cis Isomer ◽  
Chemical Class

Abstract Perylenes and perinones are separate groups of pigments categorized within the carbonyl chemical class. The two pigment groups show similarities, for example, in their chemical structural features and, to an extent, in their technical and application properties as high-performance organic pigments. Perylenes constitute a series of firmly established high-performance pigments, offering red and violet colors, and also extending to black. Synthetically, they are derived from perylene-1,4,5,8-tetracarboxylic acid. The perylenes tend to be quite expensive pigments, but their high levels of fastness properties mean that they are suitable for highly demanding applications. In particular, they offer very high heat stability. Two perinone pigments are used commercially. In their synthesis from naphthalene-1,4,5,8-tetracarboxylic acid, they are formed as mixtures of the two isomers, which can be separated. The trans isomer, CI Pigment Orange 43, is a highly important commercial pigment, especially for plastics, while the cis isomer, CI Pigment Red 194, is bordeaux in color and is of much lesser importance. The perinone, CI Pigment Orange 43, provides a brilliant orange color and has very good fastness properties. Its commercial manufacture involves a challenging multistage procedure and consequently it is one of the most expensive organic pigments on the market.

The Cockroach DCMD Neurone: I. Lateral Inhibition and the Effects of Light- and Dark-adaptation

1982 ◽  
Vol 99 (1) ◽  
pp. 61-90 ◽  
Author(s):  
DONALD H. EDWARDS
Keyword(s):  
Lateral Inhibition ◽  
Dark Adaptation ◽  
Light Adaptation ◽  
Absolute Intensity ◽  
Recurrent Network ◽  
Light Spot ◽  
Movement Detector ◽  
Threshold Response ◽  
Inhibitory Network ◽  
Local Background

1. The responses of the cockroach descending contralateral movement detector (DCMD) neurone to moving light stimuli were studied under both light- and dark-adapted conditions. 2. With light-adaptation the response of the DCMD to two moving 2° (diam.) spots of white light is less than the response to a single spot when the two spots are separated by less than 10° (Fig. 2). 3. With light-adaptation the response of the DCMD to a single moving light spot is a sigmoidally shaped function of the logarithm of the light intensity (Fig. 3a). With dark-adaptation the response of a DCMD to a single moving light spot is a bell-shaped function of the logarithm of the stimulus intensity (Fig. 3b). The absolute intensity that evokes a threshold response is about one-and-a-half log units less in the dark-adapted eye than in the light-adapted eye. 4. The decrease in the DCMD's response that occurs when two stimuli are closer than 10°, and when a single bright stimulus is made brighter, indicates that lateral inhibition operates among the afferents to the DCMD. 5. It is shown that this inhibition cannot be produced by a recurrent lateral inhibitory network. A model of the afferent path that contains a non-recurrent lateral inhibitory network can account for the response/intensity plots of the DCMD recorded under both light-adapted and dark-adapted conditions. 6. The threshold intensity of the DCMD is increased if a stationary pattern of light is present near the path of the moving spot stimulus. This is shown to be due to a peripheral tonic lateral inhibition that is distinct from the non-recurrent lateral inhibition described earlier. 7. It is suggested that the peripheral lateral inhibition acts to adjust the threshold of afferents to local background light levels, while the proximal non-recurrent network acts to enhance the acuity of the eye to small objects in the visual field, and to filter out whole-field stimuli.

External Design and Field of View of the Compound Eyes in a Raptorial Neuropteran Insect, Mantispa Styriaca

1990 ◽  
Vol 148 (1) ◽  
pp. 353-365 ◽  
Author(s):  
U. EGGENREICH ◽  
K. KRAL
Keyword(s):  
Dark Adaptation ◽  
Visual Fields ◽  
Field Of View ◽  
Compound Eyes ◽  
Praying Mantis ◽  
Binocular Field ◽  
Frontal Part

Visual fields and ommatidial angles of the compound eyes of Mantispa styriaca were determined using luminous pseudopupil and histological-anatomical techniques. The maximal horizontal overlap averaged 42.7° in femalesand 52.4° in males; females had only one overlap maximum, whereas males had two. In the dorsoventral direction, the binocular field had an overlap of 135.2° in the female and 142° in the male. In light-adapted eyes, optical acceptance angles reached values of 2.0°, and they reached 3.6° with dark adaptation; interommatidial angles were between 1.8° and 2.3°. The angles were very similar over the entire eye; no acute zone was found in the frontal part of the eye, as the large binocular overlap would suggest. The results are compared with those for the praying mantis: this animal is in no way related to Mantispa but resembles it in appearance and capture behaviour.

The Effect of Changed Extracellular Calcium and Sodium Concentration on the Electroretinogram of the Crayfish Retina

1980 ◽  
Vol 35 (3-4) ◽  
pp. 308-318 ◽  
Author(s):  
H. Stieve ◽  
I. Claßen-Linke
Keyword(s):  
Dark Adaptation ◽  
Time Course ◽  
Calcium Concentration ◽  
Light Adaptation ◽  
Sodium Concentration ◽  
Strong Increase ◽  
Calcium Stores ◽  
Half Time ◽  
Astacus Leptodactylus ◽  
External Calcium

Abstract The electroretinogram (ERG) of the isolated retina of the crayfish Astacus leptodactylus evoked by strong 10 ms light flashes at constant 5 min intervals was measured while the retina was continuously superfused with various salines which differed in Ca2+ -and Na+ -concentrations. The osmotic pressure of test- and reference-saline was adjusted to be identical by adding sucrose. Results: 1. Upon raising the calcium-concentration of the superfusate in the range of 20-150 mmol/l (constant Na+ -concentration: 208 mmol/l) the peak amplitude hmax and the half time of decay t2 of the ERG both decrease gradually up to about 50% in respect to the corresponding value in reference saline. 2. The recovery of the ERG due to dark adaptation following the “weakly light adapted state” is greatly diminished in high external [Ca2+]ex. 3. Lowering the external calcium-concentration (10 →1 mmol/l) causes a small increase in hmax and a strong increase of the half time of decay t2 (about 180%). Upon lowering the calcium concentration of the superfusate to about 1 nmol/l by 1 mmol/l of the calcium buffer EDTA, a slowly augmenting diminution of the ERG height hm SLX occurs. How­ever, a strong retardation of the falling phase of the ERG characterized by an increase in t2 occurs quickly. Even after 90 min stay in the low calcium saline the retina is still not inexcitable; hmax is 5 - 10% of the reference value. The diminution of hmax occurs about six-fold faster when the buffer concentration is raised to 10 mmol/l EDTA. 4. Additional lowering of the Na+ -concentration (208 →20.8 mmol/l) in a superfusate with a calcium concentration raised to 150 mmol/l causes a strong reduction of the ERG amplitude hmax to about 10%. 5. In a superfusate containing 1 nmol/l calcium such lowering of the sodium concentration (208 → 20.8 mmol/l) causes a diminution of the ERG height to about 40% and the shape of the ERG to become polyphasic; at least two maxima with different time to peak values are observed. Interpretation: 1. The similarity of effects, namely raising external calcium concentration and light adaptation on the one hand and lowering external calcium and dark adaptation on the other hand may indicate that the external calcium is acting on the adaptation mechanism of the photoreceptor cells, presumably by influencing the intracellular [Ca2+]. 2. The great tolerance of the retina against Ca2+ -deficiency in the superfusate might be effected by calcium stores in the retina which need high Ca2+ -buffer concentrations in the superfusate to become exhausted. 3. In contrast to the Limulus ventral nerve photoreceptor there does not seem to be an antagonis­ tic effect of sodium and calcium in the crayfish retina on the control of the light channels. 4. The crayfish receptor potential seems to be composed of at least two different processes. Lowering calcium-and lowering external sodium-concentration both diminish the height and change the time course of the two components to a different degree. This could be caused by in­ fluencing the state of adaptation and thereby making the two maxima separately visible.

A maternal defect is responsible for growth failure in vitamin D-deficient rat pups

1984 ◽  
Vol 246 (3) ◽  
pp. E216-E220
Author(s):  
R. Brommage ◽  
H. F. DeLuca
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Vitamin D3 ◽  
High Performance ◽  
Growth Failure ◽  
Female Rats ◽  
Deficient Diet ◽  
Rat Pups ◽  
Undetectable Plasma ◽  
Pup Growth

Vitamin D deficiency was induced in lactating rats and their pups by placing female rats on a vitamin D-deficient diet immediately after mating. Evidence of vitamin D deficiency included undetectable plasma levels of 25-hydroxyvitamin D3 in the dams, maternal hypocalcemia, the lack of pup growth, and pup hypocalcemia following starvation. This method of producing vitamin D-deficient pups was then used to determine whether the failure of vitamin D-deficient pups to grow properly results from a maternal or neonatal defect. Vitamin D-deficient dams and pups were injected with either vitamin D3 or the ethanol vehicle, and pup growth was monitored over the subsequent 6 days. Providing vitamin D3 to the pups directly had no effect on their growth, but administering vitamin D3 to the dams resulted in a tripling of the pup growth rate. The failure of vitamin D3 to promote pup growth when given directly to the pups was not the result of their inability to metabolize the vitamin because these pups converted [3H]-vitamin D3 to 25(OH)D3, 24,25(OH)2D3, and 1,25(OH)2D3 as determined by comigration with standards on both straight and reverse phase high-performance liquid chromatography systems. These results demonstrate that a maternal defect is responsible for the growth failure observed in vitamin D-deficient rat pups.

Changes of Acuity during Light and Dark Adaptation in the Dragonfly Compound Eye

1990 ◽  
Vol 45 (1-2) ◽  
pp. 137-142 ◽  
Author(s):  
Eric J. Warrant ◽  
Robert B. Pinter
Keyword(s):  
Dark Adaptation ◽  
Time Course ◽  
Light Adaptation ◽  
Compound Eye ◽  
Sensitivity Function ◽  
The State ◽  
Intracellular Recordings ◽  
Acceptance Angle ◽  
Angular Sensitivity ◽  
Rapid Reduction

Abstract Intracellular recordings of angular sensitivity from the photoreceptors of Aeschnid dragonflies (Hemianax papuensis and Aeschna brevistyla) are used to determine the magnitude and time course of acuity changes following alterations of the state of light or dark adaptation. Acuity is defined on the basis of the acceptance angle, Δρ (the half-width of the angular-sensitivity function). The maximally light-adapted value of Δρ is half the dark-adapted value, indicating greater acuity during light adaptation. Following a change from light to dark adaptation, Δρ increases slowly, requiring at least 3 min to reach its dark-adapted value. In contrast, the reverse change (dark to light) induces a rapid reduction of Δρ , and at maximal adapting luminances, this reduction takes place in less than 10 sec.

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