Hours Of Dark Adaptation Research Articles

First Record of Bioluminescence in a Sipunculan Worm

During a search for bioluminescent marine annelids around the island of Carrie Bow Cay, Belize, we discovered bioluminescence in the sipunculan worm Nephasoma pellucidum. The identification of N. pellucidum was verified by DNA barcoding of ∼650 bp of the mitochondrial cytochrome c oxidase I gene, using sequences of the same species from previous studies as references. Our study constitutes the first record of a bioluminescent sipunculan species. Green luminescence was detected in four of the five individuals of N. pellucidum collected from coral rubble from a shallow reef flat and one deeper (14 m) site. To test for bioluminescent activity, all collected annelids (including sipunculans) were sorted into morphotypes and identified to the lowest taxonomic level possible. After several hours of dark adaptation, they were mechanically stimulated, and luminescent reactions were noted and recorded by photography and/or video whenever possible. Of a total of nine examined sipunculan species, N. pellucidum was the only one that showed bioluminescent activity. The underlying biochemical processes for the bioluminescence are so far unknown, but transcriptome data indicate the presence of proteins with similarities to Renilla-type luciferases. We did not find similarities to any known photoproteins. Our findings broaden the known diversity of bioluminescent annelid taxa and support the notion that bioluminescence arose multiple times in annelids. The bioluminescent properties of N. pellucidum add a new reason to pursue this species as a model species, as has been previously proposed.

Oguchi's disease: two cases and literature review.

Oguchi's disease is a rare form of congenital stationary night blindness, associated with light-dependent golden fundus discoloration. In this report, we describe two cases of Oguchi's disease, both of which had two characteristic features: congenital stationary night blindness and fundoscopic manifestation of the Mizuo–Nakamura phenomenon. In both patients, fundus examination revealed a metallic sheen throughout the retina, which disappeared after 2.5 hours of dark adaptation, suggestive of the Mizuo–Nakamura phenomenon. The characteristic electroretinogram (ERG) changes (i.e., un-recordable rod response and reductions of maximal response, oscillatory potentials, and flicker response) in these patients confirmed the clinical diagnosis of Oguchi's disease. Furthermore, we discuss the results of our literature search for evidence concerning the diagnosis and pathogenesis of this rare disease. Further studies regarding the genes involved in phototransduction and light adaptation are needed to determine the pathogenesis of this rare disease.

Leaf wound induced ultraweak photon emission is suppressed under anoxic stress: Observations of Spathiphyllum under aerobic and anaerobic conditions using novel in vivo methodology.

Plants have evolved a variety of means to energetically sense and respond to abiotic and biotic environmental stress. Two typical photochemical signaling responses involve the emission of volatile organic compounds and light. The emission of certain leaf wound volatiles and light are mutually dependent upon oxygen which is subsequently required for the wound-induced lipoxygenase reactions that trigger the formation of fatty acids and hydroperoxides; ultimately leading to photon emission by chlorophyll molecules. A low noise photomultiplier with sensitivity in the visible spectrum (300–720 nm) is used to continuously measure long duration ultraweak photon emission of dark-adapting whole Spathiphyllum leaves (in vivo). Leaves were mechanically wounded after two hours of dark adaptation in aerobic and anaerobic conditions. It was found that (1) nitrogen incubation did not affect the pre-wound basal photocounts; (2) wound induced leaf biophoton emission was significantly suppressed when under anoxic stress; and (3) the aerobic wound induced emission spectra observed was > 650 nm, implicating chlorophyll as the likely emitter. Limitations of the PMT photocathode’s radiant sensitivity, however, prevented accurate analysis from 700–720 nm. Further examination of leaf wounding profile photon counts revealed that the pre-wounding basal state (aerobic and anoxic), the anoxic wounding state, and the post-wounding aerobic state statistics all approximate a Poisson distribution. It is additionally observed that aerobic wounding induces two distinct exponential decay events. These observations contribute to the body of plant wound-induced luminescence research and provide a novel methodology to measure this phenomenon in vivo.

Cyclic AMP-regulated opposing and parallel effects of serotonin and dopamine on phototaxis in the Marmorkrebs (marbled crayfish).

Phototactic behaviours are observed from prokaryotes to amphibians and are a basic form of orientation. We showed that the marbled crayfish displays phototaxis in which the behavioural response reversed from negative to positive depending on external light conditions. Animals reared in a 12-L/12-D light cycle showed negative phototaxis during daytime and positive phototaxis during night-time. Animals reared under constant light conditioning showed negative phototaxis during day- and night-time, while animals reared under constant dark conditioning showed positive phototaxis during day- and night-time. Injection of serotonin leads to a reversal of negative to positive phototaxis in both light/dark-reared and light/light-reared animals while injection of dopamine induced reversed negative phototaxis in dark/dark-reared animals. Four hours of dark adaptation were enough for light/dark-reared animals to reverse phototaxis from negative to positive. Injection of a serotonin 5HT1 receptor antagonist blocked the reverse phototaxis while serotonin 5HT2 receptor antagonists had no effects. Similarly, dark/dark-reared animals reversed to showing negative phototaxis after 4h of light adaptation. Injection of a dopamine DA1 receptor antagonist blocked this reverse phototaxis, while dopamine DA2 receptor antagonists had no effects. Injection of a cAMP analogue into light/dark-reared animals blocked reverse phototaxis after dark adaptation, while adenylate cyclase inhibitor in dark/dark-reared animals blocked reverse phototaxis after light adaptation. These results strongly suggest that serotonin mediates positive phototaxis owing to decreased cAMP levels, while dopamine-mediated negative phototaxis occurs due to increased cAMP levels. Supporting this, the ratio of serotonin to dopamine in the brain was much higher in dark/dark-reared than light/dark-reared animals.

Modified Dark Room Provocative Test for Primary Angle Closure

To examine the diagnostic value of a modified dark room provocative test (DRPT) in detecting primary closure of the anterior chamber angle. The cross-sectional observational prospective clinical study included suspects of primary angle closure. Using anterior segment optical coherence tomography (AS-OCT), we measured the anterior chamber angle configuration at room light and after 3 minutes of dark adaptation. Gonioscopy and Perkin's applanation tonometry were performed in room light conditions at baseline and after 1.5 hours of dark adaptation. The number of closed angle quadrants assessed on AS-OCT images and upon gonioscopy were recorded. The DRPT was positive, if intraocular pressure increased by ≥8 mm Hg after 1.5 hours of dark adaptation. The study included 76 subjects (76 eyes). Among 32 (42%) eyes with a positive DRPT, the number of eyes with an increased number of closed angle quadrants was significantly higher for the OCT examination at 3 minutes of dark adaptation than for gonioscopy at 1.5 hours of dark adaptation [29 (91%) eyes vs 21 (66%) eyes; P=0.01]. Kappa statistics showed a moderate agreement between increased closed angle quadrants obtained both after 3 minutes of dark adaptation (κ=0.44; P<0.001; sensitivity: 90.6%; specificity: 56.8%) and after 1.5 hours of dark room test (κ=0.45; P<0.001; sensitivity: 65.6%; specificity: 79.5%) compared with the final intraocular pressure elevation. Correspondingly, the area under the receiver operator characteristics curve was significantly larger for AS-OCT than for gonioscopy (0.86 vs 0.73; P<0.001) in predicting a positive dark room test. A modified DRPT with an anterior chamber angle assessment by OCT at 3 minutes of dark adaptation as compared with a gonioscopic angle assessment after 1.5 hours of dark adaptation had a higher diagnostic precision in predicting primary angle closure.

Correlation Between Pupil Diameter and Angle Configuration in the Dark Room Provocative Test

To study the associations between changes in pupil diameter and in the anterior chamber angle configuration during the dark room provocative test. The study included 70 suspects of primary angle closure (study group) and 40 normal participants (control group). Using anterior-segment optical coherence tomography (AS-OCT), we measured the anterior chamber angle configuration and pupil diameter at 3 minutes and at 1.5 hours of dark adaptation. In the study group, the mean number of closed angle segments was significantly (P<0.001) higher at 3 minutes of dark adaptation (3.9 ± 2.3) than at room light conditions (2.6 ± 2.2) or at 1.5 hours of dark adaptation (3.1 ± 2.1), with no statistically significant (P>0.05) difference between the 2 latter values. In the study group, the pupil diameter was significantly associated with the number of closed angle segments at 3 minutes of dark adaptation (P<0.01), but not at 1.5 hours of dark adaptation (P=0.13). Defined as an increased number of closed angle segments, the dark room test was positive in a significantly higher number of participants at 3 minutes than at 1.5 hours of dark adaptation [44 (63%) eyes vs. 31 (44%) eyes; P<0.05]. Final interocular pressure was statistically better correlated with the angle configuration segments assessed at 3 minutes (correlation coefficient r2=0.33) than at 1.5 hours of dark adaptation (r2=0.21). After short-term dark adaptation of 3 minutes, the assessment of the anterior chamber angle configuration by AS-OCT is more reliable than as if carried out after a long-term dark adaptation and may be used to identify suspects of primary angle closure.

Abstract 4385: Effect on retinal function as a mechanism for vision disorders with crizotinib (PF-02341066)

Abstract Crizotinib is a small-molecule receptor tyrosine kinase inhibitor of anaplastic lymphoma kinase (ALK) and c-Met. Crizotinib has been shown to be effective in patients with ALK-positive non-small cell lung cancer. One common adverse event that has been observed is a grade 1 vision disorder (∼45% of patients) characterized as seeing shadows or streaks during changes in lighting conditions. Onset occurs during the first weeks of treatment, with most cases improving with continued treatment and not requiring treatment discontinuation. Such vision disorders were not predicted from preclinical toxicological evaluation of crizotinib. To further understand the possible mechanism of this vision disorder, a rat electroretinography (ERG) study was conducted to determine if retinal function is altered following repeat-dose administration of crizotinib. Male Long-Evans rats (8/group) were administered crizotinib by oral gavage at a dose of 100 mg/kg/day for up to 29 days, during which an evaluation of in-life parameters (clinical signs, body weight, and food consumption), ophthalmic examinations, and ERG were performed. As part of the ERG assessment, five light-stimulation protocols were applied to test scotopic (dark-adapted) and photopic (light-adapted) luminance responses, photopic and scotopic adaptometry, and photopic flicker responses. Terminal plasma and vitreous fluid were examined for crizotinib concentrations in main study animals, and a toxicokinetic profile was obtained from a satellite group of 6 animals. Results of the ERG measurements identified a statistically significant (∼30%) reduction in mean b-wave amplitude relative to control during the initial 16 and 32 minutes of dark adaptation on Days 15 (p&amp;lt;0.05) and 29 (p&amp;lt;0.01), respectively. The magnitude of the reduction did not worsen between Days 15 and 29. Following 2 hours of dark adaptation, b-wave amplitudes were comparable between control and crizotinib-treated animals on both Days 15 and 29. There were no crizotinib-related effects observed for any other ERG parameters or during ophthalmologic examinations. Plasma exposures were ∼6-fold those associated with vision disorders in patients, and vitreous humor concentrations were 0.66-fold those in plasma at an equivalent time post-dose. Results from this preclinical model show that crizotinib causes significant reductions in the rate of retinal dark adaptation, but not the ability to achieve full dark adaptation. Vision disorders reported in the clinical setting may thus be due to direct effects on the retina rather than a central CNS effect. Whether this is a pharmacologically mediated effect at ALK or c-Met receptors expressed in retina or an off-target effect is not clear. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4385. doi:10.1158/1538-7445.AM2011-4385

Summary of the findings of the RLBP1 mutations affecting the visual cycle known so far with extremely prolonged dark adaptation in the RP of Bothnia type

Abstract Purpose The retinal diseases in the RP group associated with affected recycling of retinoids in the visual cycle is now being recognized in populations worldwide. The RLBP1 mutations are here summarized and the phenotype known so far is presented. Methods A presentation of literature in the RLBP1 mutations and the phenotype of Bothnia Dystrophy (BD) with ophthalmologic findings and full‐field electroretinography (ERGs) findings after 24 hours of dark adaptation are presented. Results The phenotype (BD) in this group is described, an early progressive maculopathy, retinitis punctata albescens (RPA) as well as peripheral retinal degenerative changes is found. An extremely prolonged dark adaptation (24h) in the BD disease is presented and the full‐field ERG (24h) show the rod b‐wave and the mixed rod‐cone a‐wave responses reached normal but delayed amplitudes in the ERGs, the increase of the oscillatory response up to normal level was found and no recovery of the cone response was found. Conclusion The phenotypes of RLBP 1 mutations worldwide and in Sweden show similarities in the expression and may be represented by the phenotype of BD. The unique findings of extremely prolonged DA and a significant and additional capacity of recovery of rod function and activity in the inner retinal layer and a continuous but slow regeneration of rod photopigment seems to occur at least up to 24h. The visual process in the RPE is retarded but also the Müller cells of the retina seem to be involved. The findings support an extremely slow synthesis of photopigments and an irreversibly disturbed cone function early in BD.

Controlling Retinal Pigment Epithelium Injury after Experimental Detachment of the Retina

Damage induced by detachment of the neural retina and the retinal pigment epithelium (RPE) can be reduced by dark adaptation. The authors evaluated the influence of the duration of dark adaptation, time of day, and modification of the melatonin-dopamine pathway on acute RPE lesions induced by mechanical detachment. BALB/c mice were studied at different times of day and different periods of dark adaptation. Some mice were treated with melatonin or sulpiride, a D2 dopamine receptor antagonist. Enucleated eyes and different saline solutions were used in experiments ex vivo. Retinal detachments in vivo were made by subretinal injections of hyaluronic acid. RPE cell damage was quantitatively evaluated with a dye exclusion procedure, and their viability was tested by preservation of tight junctions in culture. Lectin histochemistry was used to examine the interphotoreceptor matrix (IPM). Significant propidium iodide (PI) incorporation in RPE cells was detected after ex vivo separation during daytime, but it was very low when detachment took place at night after 24 to 48 hours of dark adaptation. PI exclusion was achieved during daytime after a single hour of dark adaptation when mice were pretreated with melatonin or sulpiride. Reduction of RPE cell damage was accompanied by decreased lectin binding to cone sheaths. A combination of time of day and length of dark adaptation decreased damage induced by detachment of the retina ex vivo and in vivo. Melatonin or sulpiride could replace these environmental factors. Therefore, melatonin and dopamine pathways might be involved in the control of IPM properties and retina/RPE interactions.

Photogravitropic equilibrium in Avena coleoptiles: fluence rate-response relationships and dependence on dark adaptation and clinostating.

Phototropism of Avena coleoptiles was measured in response to blue-light irradiation lasting between 2 and 24 h. During this time the coleoptiles established a bending angle of photogravitropic equilibrium that was dependent on the time of irradiation and also on the pretreatment in light or darkness prior to stimulation. The absolute threshold for the photogravitropic equilibrium in response to blue light was 10(-8) micromol m(-2) s(-1). Photon fluence rate-response curves, which were generated after several hours of dark adaptation, had a characteristic shape with a prominent optimum in the middle of the dynamic range. Curves which were generated without prior dark adaptation displayed no such optimum. Clinostating dark-adapted coleoptiles caused an increase of sensitivity and responsiveness during a 2-h period of unilateral irradiation. The advantages and the drawbacks of long-term irradiation experiments for the investigation of phototropism and the generation of action spectra are discussed.

A Case of Fundus Albipunctatus with a Retinol Dehydrogenase 5 Gene Mutation in a Child

We examined a family with fundus albipunctatus in which mutation of the retinol dehydrogenase 5(RDH 5) gene was suspected to be the cause of this disease. An 8-year-old girl had diffuse multiple white dots in her fundus except for the macula. She had good central vision. The amplitude of her electroretinogram wave was low, but it recovered after three hours of dark adaptation. Dark adaptometry showed an elevated threshold for rod adaptation. No visual field loss was observed. A homozygous missense mutation was found in exon 5 of the RDH 5 gene that substituted histidine for arginine at codon 280(Arg 280 His). Her mother had a normal fundus but was heterozygous for the same mutation. A missense mutation of RDH 5(Arg 280 His) was found in a Japanese family with fundus albipunctatus.

Macular dystrophy in a 9-year-old boy with fundus albipunctatus

PURPOSE: To report a 9-year-old boy with fundus albipunctatus and macular dystrophy.DESIGN: Observational case report.METHODS: A complete ophthalmic examination was performed. The 11-cis retinol dehydrogenase gene (RDH5) was examined by direct genomic sequencing.RESULTS: The fundi of the 9-year-old boy showed numerous yellow-white punctata as well as foveal atrophic lesions in both eyes. His corrected visual acuity was RE: 0.5 and LE: 0.3. Scotopic full-field electroretinograms were not present after 20 minutes of dark-adaptation but were normal after 3 hours of dark-adaptation. Full-field cone and 30-Hz flicker electroretinograms were normal; however, focal macular cone electroretinograms were significantly reduced. A compound heterozygous mutation of Tyr281His and Leu310GluVal in RDH5 was detected.CONCLUSION: We suggest that the macular dystrophy is caused by the RDH5 mutation as a phenotype variation in fundus albipunctatus.

Molecular genetics of Oguchi disease, fundus albipunctatus, and other forms of stationary night blindness: LVII Edward Jackson Memorial Lecture

PURPOSE: To compare the clinical findings of the various forms of stationary night blindness caused by mutations in identified genes encoding proteins of photoreceptors or the retinal pigment epithelium. METHODS: Review of the visual acuities, visual fields, fundi, dark-adaptation curves, and electroretinograms from patients with stationary night blindness caused by mutations in the genes RHO, GNAT1, PDE6B, RHOK, SAG, RDH5, and CACNA1F, respectively encoding rhodopsin, the α subunit of rod transducin, the β subunit of rod cGMP-phosphodiesterase, rhodopsin kinase, arrestin, 11- cis retinol dehydrogenase, and a retinal L-type calcium channel. RESULTS: In the evaluated forms of stationary night blindness, the time course of dark adaptation and the characteristics of the electroretinogram indicate that rod photoreceptors are present and that they function, although abnormally. In night blindness resulting from defects in rhodopsin, the α subunit of rod transducin, or the β subunit of rod cGMP phosphodiesterase, rod photoreceptors respond only to light intensities far brighter than normal, and the sensitivity of rods to light is similar to that of normal individuals who are not dark adapted. In fundus albipunctatus and in Oguchi disease, the rod photoreceptors can achieve normal sensitivity to dim light but only after 2 or more hours of dark adaptation, compared with approximately 0.5 hours for normal individuals. In each of these forms of stationary night blindness, the poor rod sensitivity and the time course of dark adaptation correlate with the known or presumed physiologic abnormalities caused by the identified gene defects. Patients with some forms of stationary night blindness, such as fundus albipunctatus and Oguchi disease, may develop degeneration of the retina leading to severe loss of vision in later life. CONCLUSIONS: The identification of the mutant genes causing forms of stationary night blindness refines the classification of these diseases and enhances our understanding of the underlying physiologic defects. Ophthalmologists must be aware that although these diseases are traditionally categorized as “stationary,” some of them lead to reduced visual acuity or constricted visual fields, especially in older patients. Efforts to develop therapies for these diseases should concentrate on these more severe forms.

BIOPHOTON EMISSION (ULTRAWEAK PHOTOEMISSION) FROM DARK ADAPTED SPINACH CHLOROPLASTS

Abstract— Biophoton emission (ultraweak photoemission) is observable in isolated spinach chloroplasts, even after several hours of dark adaptation. This spontaneous light emission is oxygen dependent, decreased by respiratory inhibitors such as cyanide or salycilhydroxamic acid, suppressed by p‐benzoquinone and enhanced by NADPH. We suggest that the respiratory chain of chloroplasts is involved in the series of redox reactions leading to the dark excitation of the emitter of biophotons, presumably chlorophyll molecules.Biophoton emission is inhibited by superoxide dismutase, implying that the univalent reduction of molecular oxygen is associated with this process, in a yet unknown way.

X-linked Recessive Cone Dystrophy With Tapetal-like Sheen

We encountered a new X-linked recessive cone dystrophy in which patients have a greenish-golden tapetal-like sheen of the retina; while the retinal sheen and electroretinographic abnormalities are present from childhood, patients are not symptomatic until adult years. All of the male patients tested showed evidence of cone dysfunction on color vision testing, dark adaptometry, and electroretinography. After three hours of dark adaptation, the tapetal-like sheen disappeared, with most areas changing from greenish-golden shades to orange-red hues (Mizuo-Nakamura phenomenon). One male patient had a retinal detachment from atrophic round holes in the equatorial retina.

STUDIES OF CHLOROPLAST DEVELOPMENT IN EUGLENA: 10. THE RETURN OF THE CHLOROPLAST TO THE PROPLASTID CONDITION DURING DARK ADAPTATION

In dark-adapting dividing cells of Euglena gracilis var. bacillaris, chloroplast lamellae gradually come apart into constituent discs which are progressively lost from the plastids. The entire process from fully formed chloroplasts containing approximately 14 lamellae, each composed of about three discs, to the proplastid (containing no internal membranes) takes about 144 hours (eight generations). Electron micrographs of the process are presented and also the kinetics of loss of discs, lamellae, and pigments. Chlorophyll is lost, at the outset, at a rate commensurate with simple dilution among chloroplasts of progeny cells. The rate of loss of discs and lamellae, however, is somewhat slower and suggests either that all chloroplasts do not divide at each cell division or that there is a continuing slow production of chloroplast membranes in the dark after pigment synthesis has stopped.In non-dividing cells, essentially no loss of structure occurs over the entire 144 hours of dark adaptation. The plastids appear to lose little or no internal structure over the entire period and never return to the proplastid condition. Chlorophyll a drops to about one-third of the original value in the first 24 hours and is lost slowly from then on.The evolutionary and ecological implications of this type of control for a cell which is a facultative phototroph or organotroph are discussed.