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https://www.readbyqxmd.com/read/28103478/modulation-of-fast-narrowband-oscillations-in-the-mouse-retina-and-dlgn-according-to-background-light-intensity
#1
Riccardo Storchi, Robert A Bedford, Franck P Martial, Annette E Allen, Jonathan Wynne, Marcelo A Montemurro, Rasmus S Petersen, Robert J Lucas
Background light intensity (irradiance) substantially impacts the visual code in the early visual system at synaptic and single-neuron levels, but its influence on population activity is largely unexplored. We show that fast narrowband oscillations, an important feature of population activity, systematically increase in amplitude as a function of irradiance in both anesthetized and awake, freely moving mice and at the level of the retina and dorsal lateral geniculate nucleus (dLGN). Narrowband coherence increases with irradiance across large areas of the dLGN, but especially for neighboring units...
January 18, 2017: Neuron
https://www.readbyqxmd.com/read/28103197/the-tuebingen-scotopic-threshold-test-tstt
#2
Torsten Strasser, Hana Langrova, Sabrina Sundermeier, Dominic Hillerkuss, Katarina Stingl, Wilhelm Durst, Anne Kurtenbach, Eberhart Zrenner, Ditta Zobor
Measurement of the dark-adaptation threshold plays a key role in the diagnosis and estimation of disease progression of many retinal disorders. Determining the threshold is, however, difficult to perform in young children. We present here a prototype for a dark adaptometer, the Tuebingen Scotopic Threshold Test (TSST) aimed to ease measurement of photoreceptor thresholds in young subjects. The device consists of two 7cm x 10cm fields with either blue or yellow LEDs, for testing rod or cone sensitivity, respectively...
January 5, 2017: IEEE Journal of Biomedical and Health Informatics
https://www.readbyqxmd.com/read/28102581/molecular-mechanisms-and-ecological-function-of-far-red-light-signalling
#3
REVIEW
David J Sheerin, Andreas Hiltbrunner
Land plants possess the ability to sense and respond to far-red light (700-760 nm), which serves as an important environmental cue. Due to the nature of far-red light, it is not absorbed by chlorophyll and thus is enriched in canopy shade, and will also penetrate deeper into soil than other visible wavelengths. Far-red light responses include regulation of seed germination, suppression of hypocotyl growth, induction of flowering, and accumulation of anthocyanins, which depend on one member of the phytochrome photoreceptor family, phytochrome A (phyA)...
January 19, 2017: Plant, Cell & Environment
https://www.readbyqxmd.com/read/28102548/the-shade-avoidance-syndrome-multiple-signals-and-ecological-consequences
#4
REVIEW
Carlos L Ballaré, Ronald Pierik
Plants use photoreceptor proteins to detect the proximity of other plants and to activate adaptive responses. Of these photoreceptors, phytochrome B (phyB), which is sensitive to changes in the red (R) to far-red (FR) ratio of sunlight, is the one that has been studied in greatest detail. The molecular connections between the proximity signal (low R:FR) and a model physiological response (increased elongation growth) have now been mapped in considerable detail in Arabidopsis seedlings. We briefly review our current understanding of these connections, and discuss recent progress in establishing the roles of other photoreceptors in regulating growth-related pathways in response to competition cues...
January 19, 2017: Plant, Cell & Environment
https://www.readbyqxmd.com/read/28101399/stimulus-evoked-outer-segment-changes-occur-before-the-hyperpolarization-of-retinal-photoreceptors
#5
Yiming Lu, Benquan Wang, David R Pepperberg, Xincheng Yao
Transient retinal phototropism (TRP) has been predominantly observed in rod photoreceptors activated by oblique visible light stimulation. Dynamic confocal microscopy and optical coherence tomography (OCT) have revealed rod outer segment (ROS) movement as the physical source of TRP. However, the physiological source of ROS movement is still not well understood. In this study, concurrent near-infrared imaging of TRP and electroretinogram (ERG) measurement of retinal electrophysiology revealed that ROS movement occurs before the onset of the ERG a-wave, which is known to reflect the hyperpolarization of retinal photoreceptors...
January 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28100658/maps-of-cone-opsin-input-to-mouse-v1-and-higher-visual-areas
#6
Issac Rhim, Gabriela Coello-Reyes, Hee-Kyoung Ko, Ian Nauhaus
Studies in the mouse retina have characterized the spatial distribution of an anisotropic ganglion cell and photoreceptor mosaic, which provides a solid foundation to study how the cortex pools from afferent parallel color channels. In particular, the mouse's retinal mosaic exhibits a gradient of wavelength sensitivity along its dorsoventral axis. Cones at the ventral extreme mainly express S-opsin, which is sensitive to ultraviolet (UV) wavelengths. Then, moving toward the retina's dorsal extreme, there is a transition to M-opsin dominance...
January 18, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28100053/the-grateful-infrared-sequential-protein-structural-changes-resolved-by-infrared-difference-spectroscopy
#7
Tilman Kottke, Víctor A Lórenz-Fonfría, Joachim Heberle
The catalytic activity of proteins is a function of structural changes. Very often these are as minute as protonation changes, hydrogen bonding changes, and amino acid side chain reorientations. To resolve these, a methodology is afforded that not only provides the molecular sensitivity but allows for tracing the sequence of these hierarchical reactions at the same time. This feature article showcases results from time-resolved IR spectroscopy on channelrhodopsin (ChR), light-oxygen-voltage (LOV) domain protein, and cryptochrome (CRY)...
January 19, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28099524/role-of-myo-nog-cells-in-neuroprotection-evidence-from-the-light-damaged-retina
#8
Alice Brandli, Jacquelyn Gerhart, Christopher K Sutera, Sivaraman Purushothuman, Mindy George-Weinstein, Jonathan Stone, Arturo Bravo-Nuevo
PURPOSE: To identify Myo/Nog cells in the adult retina and test their role in protecting retinal photoreceptors from light damage. METHODS: Light damage was induced by exposing albino rats raised in dim cyclic light to 1000 lux light for 24 hours. In one group of rats, Myo/Nog cells were purified from rat brain tissue by magnetic cell sorting following binding of the G8 monoclonal antibody (mAb). These cells were injected into the vitreous humour of the eye within 2 hours following bright light exposure...
2017: PloS One
https://www.readbyqxmd.com/read/28099315/factors-associated-with-visual-outcome-after-macula-off-rhegmatogenous-retinal-detachment-surgery
#9
Dae Hyun Park, Kyung Seek Choi, Hae Jung Sun, Sung Jin Lee
PURPOSE: To evaluate preoperative factors influencing the visual outcome and postoperative factors associated with the changes in visual acuity, after reattachment surgery to treat macula-off rhegmatogenous retinal detachment. METHODS: A total of 180 eyes of 180 patients who underwent reattachment surgery to treat macula-off rhegmatogenous retinal detachment, and who were followed up for more than 12 months, were reviewed retrospectively. Preoperative and postoperative characteristics, including optical coherence tomography findings, were comprehensively analyzed using univariate and multivariate models to evaluate preoperative factors influencing best-corrected visual acuity 12 months after macula-off rhegmatogenous retinal detachment surgery and postoperative factors associated with changes in best-corrected visual acuity after surgery...
January 17, 2017: Retina
https://www.readbyqxmd.com/read/28099314/fundus-autofluorescence-lifetimes-and-central-serous-chorioretinopathy
#10
Chantal Dysli, Lieselotte Berger, Sebastian Wolf, Martin S Zinkernagel
PURPOSE: To quantify retinal fluorescence lifetimes in patients with central serous chorioretinopathy (CSC) and to identify disease specific lifetime characteristics over the course of disease. METHODS: Forty-seven participants were included in this study. Patients with central serous chorioretinopathy were imaged with fundus photography, fundus autofluorescence, optical coherence tomography, and fluorescence lifetime imaging ophthalmoscopy (FLIO) and compared with age-matched controls...
January 17, 2017: Retina
https://www.readbyqxmd.com/read/28098347/evolutionary-origin-of-phytochrome-responses-and-signaling-in-land-plants
#11
REVIEW
Keisuke Inoue, Ryuichi Nishihama, Takayuki Kohchi
Phytochromes comprise one of the major photoreceptor families in plants, and they regulate many aspects of plant growth and development throughout the plant life cycle. A canonical land plant phytochrome originated in the common ancestor of streptophytes. Phytochromes have diversified in seed plants and some basal land plants due to lineage-specific gene duplications that occurred during the course of land plant evolution. Molecular genetic analyses using Arabidopsis thaliana suggested that there are two types of phytochromes in angiosperms, light-labile type I and light-stable type II, which have different signaling mechanisms and which regulate distinct responses...
January 18, 2017: Plant, Cell & Environment
https://www.readbyqxmd.com/read/28095637/gene-therapy-for-achromatopsia
#12
REVIEW
Stylianos Michalakis, Christian Schön, Elvir Becirovic, Martin Biel
AIM: This review summarizes the current status of Achromatopsia (ACHM) gene therapy-related research activities and provides an outlook for their clinical application. DISCUSSION: ACHM is an inherited eye disease characterized by congenital absence of cone photoreceptor function. As a consequence, ACHM is associated with strongly impaired daylight vision, photophobia, nystagmus, and lack of color discrimination. Currently, six genes have been linked to ACHM. Up to 80% of the patients carry mutations in the genes CNGA3 and CNGB3 encoding the two subunits of the cone cyclic nucleotide-gated (CNG) channel...
January 17, 2017: Journal of Gene Medicine
https://www.readbyqxmd.com/read/28094296/hydrophobic-residues-near-the-bilin-chromophore-binding-pocket-modulate-spectral-tuning-of-insert-cys-subfamily-cyanobacteriochromes
#13
Sung Mi Cho, Sae Chae Jeoung, Ji-Young Song, Ji-Joon Song, Youn-Il Park
Cyanobacteriochromes (CBCRs) are a subfamily of phytochrome photoreceptors found exclusively in photosynthetic cyanobacteria. Four CBCRs containing a second Cys in the insert region (insert-Cys) have been identified from the nonheterocystous cyanobacterium Microcoleus B353 (Mbr3854g4 and Mbl3738g2) and the nitrogen fixing, heterocystous cyanobacterium Nostoc punctiforme (NpF2164g3 and NpR1597g2). These insert-Cys CBCRs can sense light in the near-UV to orange range, but key residues responsible for tuning their colour sensitivity have not been reported...
January 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28093474/behavioral-status-influences-the-dependence-of-odorant-induced-change-in-firing-on-pre-stimulus-firing-rate
#14
Anan Li, Ethan M Guthman, Wilder T Doucette, Diego Restrepo
: The firing rate of the mitral/tufted cells in the olfactory bulb is known to undergo significant trial-to-trial variability and is affected by anesthesia. Here we ask whether odorant-elicited changes in firing rate depend on the rate before application of the stimulus in the awake and anesthetized mouse. We find that pre-stimulus firing rate varies widely on a trial-to-trial basis and that the stimulus-induced change in firing rate decreases with increasing pre-stimulus firing rate...
January 16, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28091887/the-morphology-of-human-rod-ergs-obtained-by-silent-substitution-stimulation
#15
J Maguire, N R A Parry, J Kremers, I J Murray, D McKeefry
PURPOSE: To record transient ERGs from the light-adapted human retina using silent substitution stimuli which selectively reflect the activity of rod photoreceptors. We aim to describe the morphology of these waveforms and examine how they are affected by the use of less selective stimuli and by retinal pathology. METHODS: Rod-isolating stimuli with square-wave temporal profiles (250/250 ms onset/offset) were presented using a 4 primary LED ganzfeld stimulator...
January 13, 2017: Documenta Ophthalmologica. Advances in Ophthalmology
https://www.readbyqxmd.com/read/28089909/immunosuppression-via-loss-of-il2r%C3%AE-enhances-long-term-functional-integration-of-hesc-derived-photoreceptors-in-the-mouse-retina
#16
Jie Zhu, Helen Cifuentes, Joseph Reynolds, Deepak A Lamba
Loss of photoreceptors is a common endpoint in degenerative retinal diseases. Human pluripotent stem cells provide a potential source for photoreceptor replacement, but, even in mouse models, the efficiency and efficacy of transplantation-based repair remains poor. In this study, we examined the degree to which immune rejection contributes to these disappointing outcomes using an immunodeficient IL2 receptor γ (IL2rγ)-null mouse model. Our results show that prevention of cell rejection in the normal and degenerating retinal environment significantly improves long-term survival and integration of hESC-derived donor retinal cells...
December 29, 2016: Cell Stem Cell
https://www.readbyqxmd.com/read/28089219/prognostic-factors-of-epiretinal-membranes-a-systematic-review
#17
REVIEW
A I M Miguel, A Legris
INTRODUCTION: Epiretinal membranes (ERM) have been increasingly characterized with the advent of new optical coherence tomographies (OCTs). We intended to perform a systematic review regarding prognostic factors (PF) of ERM after surgery. MATERIALS AND METHODS: Systematic review of electronic databases was performed (last date of search was 10 August 2015): Medline, Scopus, Google Scholar, clinicaltrials.gov and current controlled trials. Search queries included: "membrane", "pucker", "prognosis", "prognostic", "epiretinal", "épirétinienne"...
January 11, 2017: Journal Français D'ophtalmologie
https://www.readbyqxmd.com/read/28088625/absence-of-dj-1-causes-age-related-retinal-abnormalities-in-association-with-increased-oxidative-stress
#18
Vera L Bonilha, Brent A Bell, Mary E Rayborn, Ivy S Samuels, Anna King, Joe G Hollyfield, Chengsong Xie, Huaibin Cai
Oxidative stress alters physiological function in most biological tissues and can lead to cell death. In the retina, oxidative stress initiates a cascade of events leading to focal loss of RPE and photoreceptors, which is thought to be a major contributing factor to geographic atrophy. Despite these implications, the molecular regulation of RPE oxidative stress under normal and pathological conditions remains largely unknown. A better understanding of the mechanisms involved in regulating RPE and photoreceptors oxidative stress response is greatly needed...
January 11, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28087932/the-complexity-of-fungal-vision
#19
Reinhard Fischer, Jesus Aguirre, Alfredo Herrera-Estrella, Luis M Corrochano
Life, as we know it, would not be possible without light. Light is not only a primary source of energy, but also an important source of information for many organisms. To sense light, only a few photoreceptor systems have developed during evolution. They are all based on an organic molecule with conjugated double bonds that allows energy transfer from visible (or UV) light to its cognate protein to translate the primary physical photoresponse to cell-biological actions. The three main classes of receptors are flavin-based blue-light, retinal-based green-light (such as rhodopsin), and linear tetrapyrrole-based red-light sensors...
December 2016: Microbiology Spectrum
https://www.readbyqxmd.com/read/28087896/eag-channels-expressed-in-microvillar-photoreceptors-are-unsuited-to-diurnal-vision
#20
Esa-Ville Immonen, Andrew S French, Päivi H Torkkeli, Hongxia Liu, Mikko Vähäsöyrinki, Roman V Frolov
The principles underlying evolutionary selection of ion channels for expression in sensory neurons are unclear. Among species possessing microvillar photoreceptors the major ionic conductances have only been identified in Drosophila melanogaster. In Drosophila depolarization is provided by light-activated TRP channels with a minor contribution from TRPL channels, while repolarization is mediated by sustained voltage-gated K(+) (Kv) channels of the Shab family. Bright light stimulates Shab channels, further restricting depolarization and improving membrane bandwidth...
January 13, 2017: Journal of Physiology
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