Photoreceptors, visual pigments, and ellipsosomes in the killifish, Fundulus heteroclitus: A microspectrophotometric and histological study

2000 ◽  
Vol 17 (3) ◽  
pp. 403-420 ◽  
Author(s):  
IÑIGO NOVALES FLAMARIQUE ◽  
FERENC I. HÁROSI
Keyword(s):  
Fundulus Heteroclitus ◽  
Light Field ◽  
Histological Study ◽  
Light And Electron Microscopy ◽  
Visual Pigments ◽  
Photoreceptor Layer ◽  
Dense Bodies ◽  
Cone Type ◽  
Underwater Irradiance ◽  
Cone Density

The photoreceptor layer of F. heteroclitus was examined by light and electron microscopy. We identified four cone visual pigments with maximum absorbance (λmax) in the UV (363 nm), short (400 nm), middle (463 nm), and long (563 nm) wavelength regions of the spectrum and a rod visual pigment that peaked in the middle wavelengths (503 nm). Electron-dense bodies, ellipsosomes and pseudoellipsosomes, were present in the distal ellipsoids of long/middle (L/M) and long/long (L/L) wavelength double cones and in single short wavelength (S) cones, respectively. The light absorption of ellipsosomes indicated the presence of reduced cytochrome-c with the highest optical densities found in the M members of L/M double cones. By contrast, S cones contained pseudo-ellipsosomes which had very low optical density. UV cones were present everywhere as part of square or row mosaics in the retina of F. heteroclitus. Cone packing was on average higher for locations in the upper half of the retina while the highest cone density was found in the centro-ventral retina. An analysis of potential quantum catches for each cone type as a function of retinal sector and underwater irradiance characteristics revealed higher overall quantum catches for cones in the upper retina when the light field was assumed homogeneous, and higher quantum catches for cones in the lower retina when downwelling, horizontal, and upwelling irradiances were considered separately. At dusk, quantum catch was highest for M cones and the contribution to the overall retinal quantum catch by UV and S cones was much greater than during daylight hours. We propose that UV and S cones may be used to detect targets of interest against the background irradiance sensed by double cones.

The cyphonautes larva of the marine bryozoan Membranipora membranacea. II. Internal sac, musculature, and pyriform organ

1988 ◽  
Vol 66 (2) ◽  
pp. 384-398 ◽  
Author(s):  
Stephen A. Stricker ◽  
Christopher G. Reed ◽  
Russel L. Zimmer
Keyword(s):  
Secretory Granules ◽  
Light And Electron Microscopy ◽  
Neck Region ◽  
Adductor Muscle ◽  
Ciliated Cells ◽  
Membranipora Membranacea ◽  
Dense Bodies ◽  
Excretory Organ ◽  
Glandular Cells ◽  
Cytological Features

The internal sac, muscles, and pyriform organ of the cyphonautes larva of Membranipora membranacea (phylum Bryozoa, order Cheilostomata) were examined by light and electron microscopy. The internal sac is an ovoid, tripartite organ that lies near the larval gut. The posterior and lateral parts of the sac are composed of nonglandular epithelial cells and are referred to as the roof and wall regions, respectively. The neck region occurring at the anterior end of the sac is packed with large secretory granules and is folded posteriorly into the lumen surrounded by the roof and wall regions. A previously undescribed network of ciliated cells, which may constitute part of an excretory organ, occurs between the internal sac and the gut. Four major sets of muscles are present in the larva: (i) a single adductor muscle that attaches to the two valves of the larval shell and contains non-striated myofibers with conspicuous dense bodies, (ii) a pair of nonstriated sac muscles that extend between the shell and the roof region of the internal sac, (iii) two sets of striated lateral muscles which originate near the center of the shell and ramify along the sides of the larva, and (iv) a median band of striated myofibers located along both the anterior and posterior margins of the larva. The pyriform organ is a large neuroglandular complex located at the anterior end of the larva. The organ consists of (i) a median ciliated groove with an anteriorly positioned tuft of long cilia, (ii) numerous glandular cells surrounding the ciliated groove, and (iii) several discrete tracts of nerves with accompanying muscles. The cytological features of the internal sac, larval muscles, and pyriform organ are compared with those described for other bryozoan larvae.

scholarly journals Histological Studies on the Retina of the Falcon "S Eye Ball (Circus Cyaneus C.) Under Light and Electron Microscopy

2012 ◽  
Vol 36 (2) ◽  
pp. 83-92
Author(s):  
Samawal Jassim Mohamed Al-Robaae
Keyword(s):  
Histological Study ◽  
Light And Electron Microscopy ◽  
Plexiform Layer ◽  
Internal Limiting Membrane ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Histological Studies ◽  
Rods And Cones ◽  
Pigmented Epithelium ◽  
Circus Cyaneus

The histological study showed that the retina of falcon"s eyeball was thin at the peripheryand ranges between 0.6-0.8 μ but it was thick at center 1.68-2.64 μ. The retina consists fromten layers: pigmented epithelium, rods and cons layer, external nuclear layer, externalplexiform layer, internal nuclear layer, internal plexiform layer, Gangilionic cells layer,neurofibres layer and internal limiting membrane layer. The ultra-structural study stated thatthe rods and cons layers contained single rods with single and double cons. The retinacharacterized by lacking of the oil droplets in the internal segments of rods with narrowexternal plexiform layer in order to form network connecting rods and cones, horizontal cells,bipolar cells and Muller's cells.

Rod and cone-type photoreceptors in the post-equatorial region of the albino rat retina: a morphometric analysis of their incidence and fine structure

1978 ◽  
Vol 36 (2) ◽  
pp. 610-611
Author(s):  
K. M. Jonson ◽  
R. A. Champion ◽  
C. D. Shorey ◽  
P. E. Beaumont
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Outer Segment ◽  
Receptor Cell ◽  
Equatorial Region ◽  
Albino Rat ◽  
Rat Retina ◽  
Photoreceptor Layer ◽  
Cone Type ◽  
Type Receptor

The existence of cones in the rat retina is controversial. Although the rat has been thought to possess an exclusive rod retina (Lashley, 1932; Detwiler, 1943), Walls (1934) reported the existence of “typical cones” essentially similar to those of the primate. More recent light and electron microscope studies have also reported on the presence of cones in the rat retina (Leure-duPree, 1974; LaVail, 1976). A quantitative analysis of their incidence and fine structure has not previously been reported.The results of the present investigation demonstrate that although the rat photoreceptor layer is rod-dominant, approximately 17% of its cells would, on morphological grounds, qualify as “cone-type” receptors. These, however, are not typical cones, as their inner and outer segments do not show the characteristic conical taper and appear morphologically similar to the slender cylindrical-shaped rod inner and outer segment. Apart from this, the rat cone-type receptor cell does resemble the cone typically observed in other species.

Visual pigments in the early life stages of Pacific northwest marine fishes

2001 ◽  
Vol 204 (14) ◽  
pp. 2581-2587 ◽  
Author(s):  
Lyle L. Britt ◽  
Ellis R. Loew ◽  
William N. McFarland
Keyword(s):  
Pacific Northwest ◽  
Marine Fish ◽  
Short Wavelength ◽  
Fish Larvae ◽  
Visual Pigments ◽  
Rods And Cones ◽  
Marine Fish Larvae ◽  
Wavelength Sensitivity ◽  
Single Instance ◽  
Cone Type

SUMMARY Microspectrophotometry was used to measure the visual pigments in the rods and cones of 22 species of marine fish larvae netted from the surface waters off Friday Harbor Laboratories, Washington, USA. 13 species had rods, 12 of which contained visual pigments with a wavelength of maximum absorbance near 500nm, while one, the sand lance (Ammodytes hexapterus), had its absorbance maximum at 482nm. The 22 species of fish larvae possessed varied combinations of single, double and twin cones, ranging in peak absorbance from 353nm to 584nm. Of these, green-sensitive single cones were present in 20 of the 22 species, and were the dominant cone type. Double and twin cones were present in 13 of the species. Most common were identical green-sensitive (twin) cones (in 11 species). Green/yellow-sensitive double cones occurred in four species. In a single instance (Hemilepidotus hemilepidotus) twin blue-sensitive, twin green-sensitive and double blue/yellow-sensitive cones were recorded. Of particular interest was the finding that 18 of the species had ultraviolet- and/or violet-absorbing single cones. It has been suggested that short-wavelength photosensitivity may be beneficial for planktivory by extending the spectral range over which vision can occur. The high percentage (82%) of ultraviolet and violet visual pigments in Pacific northwest fish larvae supports the prediction that short-wavelength sensitivity may be common in marine fish larvae.

scholarly journals Visual pigments in a palaeognath bird, the emu Dromaius novaehollandiae : implications for spectral sensitivity and the origin of ultraviolet vision

2016 ◽  
Vol 283 (1834) ◽  
pp. 20161063 ◽  
Author(s):  
Nathan S. Hart ◽  
Jessica K. Mountford ◽  
Wayne I. L. Davies ◽  
Shaun P. Collin ◽  
David M. Hunt
Keyword(s):  
Spectral Sensitivity ◽  
Visual Pigment ◽  
Spectral Characteristics ◽  
Bird Species ◽  
Visual Pigments ◽  
Ancestral State ◽  
Avian Evolution ◽  
Retinal Photoreceptors ◽  
Cone Type ◽  
Dromaius Novaehollandiae

A comprehensive description of the spectral characteristics of retinal photoreceptors in palaeognaths is lacking. Moreover, controversy exists with respect to the spectral sensitivity of the short-wavelength-sensitive-1 (SWS1) opsin-based visual pigment expressed in one type of single cone: previous microspectrophotometric (MSP) measurements in the ostrich ( Struthio camelus ) suggested a violet-sensitive (VS) SWS1 pigment, but all palaeognath SWS1 opsin sequences obtained to date (including the ostrich) imply that the visual pigment is ultraviolet-sensitive (UVS). In this study, MSP was used to measure the spectral properties of visual pigments and oil droplets in the retinal photoreceptors of the emu ( Dromaius novaehollandiae ). Results show that the emu resembles most other bird species in possessing four spectrally distinct single cones, as well as double cones and rods. Four cone and a single rod opsin are expressed, each an orthologue of a previously identified pigment. The SWS1 pigment is clearly UVS (wavelength of maximum absorbance [ λ max ] = 376 nm), with key tuning sites (Phe86 and Cys90) consistent with other vertebrate UVS SWS1 pigments. Palaeognaths would appear, therefore, to have UVS SWS1 pigments. As they are considered to be basal in avian evolution, this suggests that UVS is the most likely ancestral state for birds. The functional significance of a dedicated UVS cone type in the emu is discussed.

Condensed tannins in sainfoin. II. Occurrence and changes during leaf development

1995 ◽  
Vol 73 (10) ◽  
pp. 1540-1547 ◽  
Author(s):  
G. L. Lees ◽  
M. Y. Gruber ◽  
N. H. Suttill
Keyword(s):  
Electron Microscopy ◽  
Leaf Development ◽  
Condensed Tannins ◽  
Histological Study ◽  
Condensed Tannin ◽  
Light And Electron Microscopy ◽  
Leaf Primordia ◽  
Tissue Samples ◽  
Onobrychis Viciifolia ◽  
Mature Phase

A histological study examined condensed tannin (CT) formation in plant tissue samples taken from the meristematic area of very young sainfoin (Onobrychis viciifolia Scop.) seedlings and from leaflets sampled at various stages of development in mature plants growing in the greenhouse. Light and electron microscopy revealed no CT in the seedling meristem and leaf primordia, but CTs were seen very early in leaf development forming first in the vacuoles of discrete cells of the abaxial subepidermal layer when the leaflets were recognizable, but still folded. Immature leaflets collected from the growing point of a mature sainfoin plant show similar CT formation with the abaxial cell vacuoles filled with CT when the new leaves have reached the 90°-fold stage. As the leaflets unfold and mature, CTs begin to appear in the vacuoles of small, but discrete cells in the adaxial subepidermal layer while the tannin-containing cells in the abaxial subepidermal layer begin to lose CT. The CT continues to increase in the adaxial layer until typical enlarged tannin idioblasts or sacs are observed at full leaflet expansion and maturity. By this stage, the vacuoles in the abaxial layer are almost empty. In senescing leaflet samples collected from the leaf rachis attached to the last and second to last node near the base of the plant, the cells in both subepidermal layers have lost the majority of the CT that was originally formed. At senescence all tannin-containing cells appear as empty shells. We speculate that a finite amount of CT is formed in the two subepidermal layers of new leaves at different stages of early leaf development, does not increase during the mature phase, and is catabolized in older leaves and during senescence. Key words: condensed tannins, sainfoin, Onobrychis viciifolia, leaf development.

Studies on the eyes of New Zealand parrot-fishes (Labridae)

1974 ◽  
Vol 186 (1084) ◽  
pp. 217-247 ◽  
Keyword(s):  
New Zealand ◽  
Light Adaptation ◽  
Pigment Epithelium ◽  
Red Light ◽  
Light And Electron Microscopy ◽  
Basal Region ◽  
External Limiting Membrane ◽  
Photoreceptor Layer ◽  
Cone Mosaic ◽  
Retinal Pigments

An investigation was made of the pigment epithelium and photoreceptor layer of the eyes of New Zealand parrot-fishes Pesudolabrus miles , P. celidotus and P. pittensis (Labridae). Eyes were studied by light and electron microscopy, and characteristics of the retinal pigments were investigated. The pigment epithelium contains numerous melanosomes in the basal region of the cell and red cylinders within the processes. Melanosomes and cylinders are dispersed slightly vitread during light- adaptation. The photoreceptors comprise long single cones, short single cones, double cones and rods. The cones possess a lateral sac connected to the outer segment, and well-developed calycal processes arising from the ellipsoid. Rods are without a lateral sac and have fewer and less regularly arranged calycal processes. The membranes of rod lamellae stacks are more widely spaced than those of cones and are deeply dissected by a few longitudinal fissures. Cones form a regular mosaic of squares throughout the depth of the retina scleral to the external limiting membrane. Rods are numerous and distributed throughout the cone mosaic with no particular patterns. Cones undergo only very limited radial movements, and long single cones are always buried in the pigment epithelium where they are surrounded by red pigment. Rods shorten in darkness and come to lie inside the pigment epithelium. The red material in the cylinders is apparently a new pigment; it absorbs strongly below 560 nm, and prevents all but red light from reaching the long single cones and the rods when extended. Several features and consequences of this organization are discussed.

scholarly journals Persistent Dark Cones in Oligocone Trichromacy Revealed by Multimodal Adaptive Optics Ophthalmoscopy

2021 ◽  
Vol 13 ◽  
Author(s):  
Joanne Li ◽  
Tao Liu ◽  
Oliver J. Flynn ◽  
Amy Turriff ◽  
Zhuolin Liu ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Visual Acuity ◽  
Color Vision ◽  
Adaptive Optics ◽  
Retinal Sensitivity ◽  
Photoreceptor Layer ◽  
Normal Visual Acuity ◽  
Normal Color Vision ◽  
Retinal Disorders ◽  
Cone Density

Dark cone photoreceptors, defined as those with diminished or absent reflectivity when observed with adaptive optics (AO) ophthalmoscopy, are increasingly reported in retinal disorders. However, their structural and functional impact remain unclear. Here, we report a 3-year longitudinal study on a patient with oligocone trichromacy (OT) who presented with persistent, widespread dark cones within and near the macula. Diminished electroretinogram (ERG) cone but normal ERG rod responses together with normal color vision confirmed the OT diagnosis. In addition, the patient had normal to near normal visual acuity and retinal sensitivity. Occasional dark gaps in the photoreceptor layer were observed on optical coherence tomography, in agreement with reflectance AO scanning light ophthalmoscopy, which revealed that over 50% of the cones in the fovea were dark, increasing to 74% at 10° eccentricity. In addition, the cone density was 78% lower than normal histologic value at the fovea, and 20–40% lower at eccentricities of 5–15°. Interestingly, color vision testing was near normal at locations where cones were predominantly dark. These findings illustrate how a retina with predominant dark cones that persist over at least 3 years can support near normal central retinal function. Furthermore, this study adds to the growing evidence that cones can continue to survive under non-ideal conditions.

Mouse Hepatoblastomas: A Histologic, Ultrastructural, and Immunohistochemical Study

1988 ◽  
Vol 25 (4) ◽  
pp. 286-296 ◽  
Author(s):  
T. Nonoyama ◽  
F. Fullerton ◽  
G. Reznik ◽  
T. J. Bucci ◽  
J. M. Ward
Keyword(s):  
Electron Microscopy ◽  
Tumor Cells ◽  
Immunohistochemical Study ◽  
Light And Electron Microscopy ◽  
Alpha Fetoprotein ◽  
Cell Populations ◽  
Bile Canaliculi ◽  
Cytoplasmic Organelles ◽  
Dense Bodies ◽  
Hepatocellular Adenomas

Hepatoblastomas from B6C3F1 and BALB/c mice were examined by light and electron microscopy and by immunohistochemical reactions for alpha-fetoprotein, keratin, and vimentin. Tumors occurred in one group of a chronic bioassay for the interaction of diet, genetic strain, and the carcinogen, 2-acetylaminofluorene. Tumors had several populations (including epithelial and mesenchymal cells) in various stages of differentiation. Neoplastic epithelial cells had features of embryonal hepatocytes, such as sparse cytoplasmic organelles, absence of glycogen, abundant free ribosomes, occasional bile canaliculi, and peroxisome-like dense bodies. Embryonal fibroblast-like cells had pleomorphic and folded nuclei with prominent perinuclear chromatin and dispersed cytoplasmic organelles. Fibroblast-like cells were surrounded by bundles of collagen fibrils. Intermediate or transitional types of cells were seen. No tumor cells were immunoreactive for mouse alpha-fetoprotein (AFP) antibody, unlike those in hepatocellular adenomas or carcinomas. Epithelial and mesenchymal tumor cells contained intermediate filaments throughout the cytoplasm; some of these cells stained for keratin but not for vimentin. These findings suggest that mouse hepatoblastomas are derived from bipotential liver blastema cells and are composed of a mixture of several cell populations.

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