MORPHOLOGICAL TYPES AND ARRANGEMENT OF CONE CELLS, AND THE VISUAL ACUITY OF SUTCHI CATFISH PANGASIANODON HYPOPHTHALMUS

2015 ◽  
Vol 77 (25) ◽  
Author(s):  
Nai Han Tan ◽  
Yukinori Mukai
Keyword(s):  
Visual Acuity ◽  
Photoreceptor Cells ◽  
Spatial Arrangement ◽  
Cone Cell ◽  
Pangasianodon Hypophthalmus ◽  
Cone Cells ◽  
Fundamental Understanding ◽  
Single Cone ◽  
Sutchi Catfish ◽  
Cell Densities

The density and spatial arrangement of photoreceptor cells in the retina reflect the visual environment of a fish. The density of photoreceptor cells also determines the visual acuity. In this study, the morphological types and arrangement of cone cells, and the visual acuity of sutchi catfish Pangasianodon hypophthalmus were determined to obtain fundamental understanding of its vision. The left eyes of the adult sutchi catfish were enucleated, fixed in Bouin’s solution for 24 hours and then preserved in 70% ethanol. The fixed retinae were cut into 17 regions. The nine major regions were the dorso-nasal (DN), dorsal (D), dorso-temporal (DT), nasal (N), bottom (B), temporal (T), ventro-nasal (VN), ventral (V), and ventro-temporal (VT). The 17 regions were then immersed separately in a series of ethanol (from 70% to 100%), cleared with histolene, embedded in paraffin, cut into 6 μm thick tangential sections, and stained with haematoxylin-eosin. The density of cone cells per 0.01 mm2 in each region was counted from the stained sections. Visual acuity was then calculated using cone cell densities and lens radii. Only one type of cone cells, which is the single cone cell, was identified and these single cone cells were closely spaced. The area around the bottom region showed tendency of higher density of single cone cells. These findings provide the fundamental understanding on the adaptation of retinal structure of sutchi catfish to its feeding behaviour.     

Spindle shaped bodies in foveolar cones of the baboon retina

1989 ◽  
Vol 47 ◽  
pp. 960-961
Author(s):  
W. Krebs ◽  
I. Krebs
Keyword(s):  
Cross Sections ◽  
Inclusion Bodies ◽  
Photoreceptor Cells ◽  
Papio Anubis ◽  
Retinal Photoreceptor ◽  
Age Related ◽  
Cone Cells ◽  
Membrane Bound ◽  
Oriented Parallel ◽  
Shaped Inclusion

Various inclusion bodies occur in vertebrate retinal photoreceptor cells. Most of them are membrane bound and associated with phagocytosis or they are age related residual bodies. We found an additional inclusion body in foveal cone cells of the baboon (Papio anubis) retina.The eyes of a 15 year old baboon were fixed by immersion in cacodylate buffered glutaraldehyde (2%)/formaldehyde (2%) as described in detail elsewhere . Pieces of retina from various locations, including the fovea, were embedded in epoxy resin such that radial or tangential sections could be cut.Spindle shaped inclusion bodies were found in the cytoplasm of only foveal cones. They were abundant in the inner segments, close to the external limiting membrane (Fig. 1). But they also occurred in the outer fibers, the perikarya, and the inner fibers (Henle’s fibers) of the cone cells. The bodies were between 0.5 and 2 μm long. Their central diameter was 0.2 to 0. 3 μm. They always were oriented parallel to the long axis of the cone cells. In longitudinal sections (Figs. 2,3) they seemed to have a fibrous skeleton that, in cross sections, turned out to consist of plate-like (Fig.4) and tubular profiles (Fig. 5).

The Drosophila orphan nuclear receptor seven-up requires the Ras pathway for its function in photoreceptor determination

Development ◽  
1995 ◽  
Vol 121 (1) ◽  
pp. 225-235 ◽  
Author(s):  
G. Begemann ◽  
A.M. Michon ◽  
L. vd Voorn ◽  
R. Wepf ◽  
M. Mlodzik
Keyword(s):  
Cell Fate ◽  
Nuclear Receptor ◽  
Egf Receptor ◽  
Cell Transformation ◽  
Orphan Nuclear Receptor ◽  
Loss Of Function ◽  
Cone Cell ◽  
Ras Pathway ◽  
Protein Levels ◽  
Cone Cells

The Drosophila seven-up (svp) gene specifies outer photoreceptor cell fate in eye development and encodes an orphan nuclear receptor with two isoforms. Transient expression under the sevenless enhancer of either svp isoform leads to a dosage-dependent transformation of cone cells into R7 photoreceptors, and at a lower frequency, R7 cells into outer photoreceptors. To investigate the cellular pathways involved, we have taken advantage of the dosage sensitivity and screened for genes that modify this svp-induced phenotype. We show that an active Ras pathway is essential for the function of both Svp isoforms. Loss-of-function mutations in components of the Ras signal transduction cascade act as dominant suppressors of the cone cell transformation, whilst loss-of-function mutations in negative regulators of Ras-activity act as dominant enhancers. Furthermore, Svp-mediated transformation of cone cells to outer photoreceptors, reminiscent of its wild-type function in specifying R3/4 and R1/6 identity, requires an activated Ras pathway in the same cells, or alternatively dramatic increase in ectopic Svp protein levels. Our results indicate that svp is only fully functional in conjunction with activated Ras. Since we find that mutations in the Egf-receptor are also among the strongest suppressors of svp-mediated cone cell transformation, we propose that the Ras activity in cone cells is due to low level Egfr signaling. Several models that could account for the observed svp regulation by the Ras pathway are discussed.

Development of sensory organs and changes of behavior in larvae of the sutchi catfish, Pangasianodon hypophthalmus

2010 ◽  
Vol 76 (6) ◽  
pp. 921-930 ◽  
Author(s):  
Yukinori Mukai ◽  
Audrey Daning Tuzan ◽  
Sitti Raehanah Muhamad Shaleh ◽  
Bernardette Mabel Manjaji-Matsumoto
Keyword(s):  
Sensory Organs ◽  
Pangasianodon Hypophthalmus ◽  
Sutchi Catfish

Deletion of the Impg2 gene causes the degeneration of rod and cone cells in mice

2020 ◽  
Vol 29 (10) ◽  
pp. 1624-1634
Author(s):  
Huijuan Xu ◽  
Chao Qu ◽  
Li Gan ◽  
Kuanxiang Sun ◽  
Junkai Tan ◽  
...  
Keyword(s):  
Cell Death ◽  
Er Stress ◽  
Molecular Mechanisms ◽  
Histopathological Examination ◽  
Apoptotic Cell ◽  
Macular Dystrophy ◽  
Cone Cell ◽  
Rod Cells ◽  
Cone Cells

Abstract Variants in interphotoreceptor matrix proteoglycans (IMPG2) have been reported in retinitis pigmentosa (RP) and vitelliform macular dystrophy (VMD) patients. However, the underlying molecular mechanisms remain elusive due to a lack of suitable disease models. We developed two independent Impg2 knockout (KO) mouse models using the CRISPR/Cas9 technique to assess the in vivo functions of Impg2 in the retina. Impg2 ablation in mice recapitulated the RP phenotypes of patients, including an attenuated electroretinogram (ERG) response and the progressive degeneration of photoreceptors. The histopathological examination of Impg2-KO mice revealed irregularly arranged rod cells and mislocalized rhodopsin protein in the inner segment at 6 months of age. In addition to the pathological changes in rod cells, cone cells were also affected in KO retinas. KO retinas exhibited progressive cone cell death and impaired cone cell elongation. Further immunoblotting analysis revealed increased levels of endoplasmic reticulum (ER) stress-related proteins, including C/EBP homologous protein (CHOP), immunoglobulin heavy-chain-binding protein (BIP) and protein disulfide isomerase (PDI), in Impg2-KO mouse retinas. Increased gliosis and apoptotic cell death were also observed in the KO retinas. As autophagy is closely associated with ER stress, we then checked whether autophagy was disturbed in Impg2-KO mouse retinas. The results showed that autophagy was impaired in KO retinas, as revealed by the increased accumulation of SQSTM1 and other proteins involved in autophagy. Our results demonstrate the essential roles of Impg2 in the retina, and this study provides novel models for mechanistic investigations and development of therapies for RP caused by IMPG2 mutations.

Feeding behavior under dark conditions in larvae of sutchi catfish Pangasianodon hypophthalmus

2010 ◽  
Vol 76 (3) ◽  
pp. 457-461 ◽  
Author(s):  
Yukinori Mukai ◽  
Audrey Daning Tuzan ◽  
Leong Seng Lim ◽  
Syahirah Yahaya
Keyword(s):  
Feeding Behavior ◽  
Pangasianodon Hypophthalmus ◽  
Sutchi Catfish ◽  
Dark Conditions

A Model of Human Cone Based on Physiological Distribution

2013 ◽  
Vol 364 ◽  
pp. 838-842
Author(s):  
Fei Long Duan ◽  
Zhi Jie Wang
Keyword(s):  
Distribution Function ◽  
Cell Model ◽  
Retinal Prosthesis ◽  
Physiological Data ◽  
Function Model ◽  
Cone Cell ◽  
Model Based ◽  
Distribution Features ◽  
Cone Cells

A good computer retinal model is the key to realize retinal prosthesis. In some of the previous studies, the modeling of cone cell was not considered in retinal models; in other studies, although the model of cone cell was included in the retinal models, its distribution features was hardly taken into consideration at all. In this paper we present an improved cone cell model and realize the model based on cameras. First, based on the physiological data that cone cell is high in the fovea and falls quickly with eccentricity increased, distribution function model of the retina is successfully built in a realistic way. Second, considering non-homogeneity distribution feature of the cone cells, we build a corresponding function between the pixel and the cone cell for simulating retina with a camera. Third, the cone cell model based on its distribution features is constructed. In the end, simulation is carried out for the model, and it is verified that the model is useful for the design of retinal prosthesis.

scholarly journals THE STRUCTURE AND CONCENTRATION OF SOLIDS IN PHOTORECEPTOR CELLS STUDIED BY REFRACTOMETRY AND INTERFERENCE MICROSCOPY

1957 ◽  
Vol 3 (1) ◽  
pp. 15-30 ◽  
Author(s):  
Richard L. Sidman
Keyword(s):  
Photoreceptor Cells ◽  
Interference Microscopy ◽  
Refractive Indices ◽  
Rod Outer Segments ◽  
Vertebrate Species ◽  
Rods And Cones ◽  
Outer Segments ◽  
Retinal Rods ◽  
Cone Cells ◽  
Longitudinal Fiber

Fragments of freshly obtained retinas of several vertebrate species were studied by refractometry, with reference to the structure of the rods and cones. The findings allowed a reassessment of previous descriptions based mainly on fixed material. The refractometric method was used also to measure the refractice indices and to calculate the concentrations of solids and water in the various cell segments. The main quantitative data were confirmed by interference microscopy. When examined by the method of refractometry the outer segments of freshly prepared retinal rods appear homogeneous. Within a few minutes a single eccentric longitudinal fiber appears, and transverse striations may develop. These changes are attributed to imbibition of water and swelling in structures normally too small for detection by light microscopy. The central "core" of outer segments and the chromophobic disc between outer and inner segments appear to be artifacts resulting from shrinkage during dehydration. The fresh outer segments of cones, and the inner segments of rods and cones also are described and illustrated. The volumes, refractive indices, concentrations of solids, and wet and dry weights of various segments of the photoreceptor cells were tabulated. Rod outer segments of the different species vary more than 100-fold in volume and mass but all have concentrations of solids of 40 to 43 per cent. Cone outer segments contain only about 30 per cent solids. The myoids, paraboloids, and ellipsoids of the inner segments likewise have characteristic refractive indices and concentrations of solids. Some of the limitations and particular virtues of refractometry as a method for quantitative analysis of living cells are discussed in comparison with more conventional biochemical techniques. Also the shapes and refractive indices of the various segments of photoreceptor cells are considered in relation to the absorption and transmission of light. The Stiles-Crawford effect can be accounted for on the basis of the structure of cone cells.

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