蟋蟀视觉系统的解剖结构与生理机能

蟋蟀视觉系统由单眼、复眼、视叶三部分组成。蟋蟀的单眼为背单眼,由角膜、角膜生成细胞、视网膜等组成,是提高昆虫复眼所感知的视觉刺激的兴奋水平部位;复眼是最主要的视觉器官,由角膜、晶锥、感杆束和网膜细胞、基膜组成,是光电转导和视觉级联反应的中心;视叶由神经节层、外髓和内髓组成,是视觉神经系统的中心。     

Actin in cellular components of the basement membrane of the compound eye of a blowfly

The so-called 'basement membrane' of arthropod compound eyes is known to be of heterogeneous origin (Odselius and Eloffson 1981). A major contribution in Diptera with open rhabdoms is provided by a pigmented component which lies at the basal end of the extracellular space of each ommatidium and fills it, the glial plug. Ancillary components consist of the expanded tips of cone cell processes. Each glial plug exhibits two distinct regions: ramifying processes extend into the extracellular space and contain numerous pigment granules, while proximally the cytoplasm is devoid of granules but packed with bundles of cross-linked microfilaments that bind the fluorescent F-actin probe NBD-phallacidin strongly and antibodies to scallop actin weakly. Cone cell expansions also contain microfilaments and exhibit the same binding properties. The proximal faces of the cells of the glial plugs and of the cone cell expansions are covered with a coarsely fibrillar extracellular matrix. Some actin bundles appear to be attached to the plasma membranes at their ends, although the reality of this arrangement is still in question. Cellular components of the basement membrane are bonded together by their extracellular matrices, so that collectively they provide a reinforced network that retains the retina. Bundles of axons from the photoreceptors and tracheae that supply the retina with tracheoles pass through the spaces in this network.     

Regulation of mammary epithelial cell function: a role for stromal and basement membrane matrices

Summary Interactions between epithelial cells and their environment are critical for normal function. Mammary epithelial cells require hormonal and extracellular matrix (ECM) signalling for the expression of tissue specific characteristics. With regard to ECM, cultured mammary epithelial cells synthesize and secrete milk proteins on stromal collagen I matrices. The onset of function coincides both with morphogenesis of a polarized epithelium and with deposition of basement membrane ECM basal to the cell layer. Mammary specific morphogenesis and biochemical differentiation is induced if mammary cells are cultured directly on exogenous basement membrane (EHS). Thus ECM may effect function by the concerted effect of permissivity for cell shape changes and the direct biochemical signalling of basement membrane molecules.A model is discussed where initial ECM control of mammary epithelial cell function originates in the interstitial matrix of stroma and subsequently transfers to the basement membrane when the epithelial cells have accumulated and deposited an organized basement membrane matrix.Dedicated to Professor Stuart Patton on the occasion of his 70th birthday.     

Synthesis and localization of two sulphated glycoproteins associated with basement membranes and the extracellular matrix

Two sulphated glycoproteins (sgps) of apparent molecular weight (Mr) 180,000 and 150,000, are synthesized by murine PYS and PF HR9 parietal endoderm and Swiss 3T3 cells. The Mr 150,000 sgp has a similar chemical structure to the sulphated glycoprotein, C, synthesized and laid down in Reichert's membrane by mouse embryo parietal endoderm cells (Hogan, B. L.M., A. Taylor, and A.R. Cooper, 1982, Dev. Biol., 90:210-214). Both the Mr 180,000 and 150,000 sgps are deposited in the detergent- insoluble matrix of cultured cells, but they do not apparently undergo any disulphide-dependent intermolecular interactions and are not precursors or products of each other. They contain asparagine-linked oligosaccharides, but these are not the exclusive sites of sulphate labeling. Antiserum raised against the Mr 150,000 sgp C of Reichert's membranes has been used in an immunohistochemical analysis of rat skin. In early foetal and adult skin the antigen is present only in basement membranes, but transiently before and after birth it is also found throughout the upper part of the dermis. This suggests that 150,000 sgp C is at times synthesized by nonepithelial cells and contributes to the extracellular matrix of mesenchymal tissues.     

The ultrastructural organization of the visual system of the wax moth,Galleria mellonella: The optic tract

Summary The ultrastructural organization of the axons of retinula cells of the eye of the wax moth Galleria mellonella are described. The axons traverse an appreciable distance between the basement membrane of the retina and the lamina ganglionaris of the optic lobe of the brain. The optic tract was reconstructed from serial thin sections. Axons emanating from a single ommatidium are closely associated together in the optic tract. Adjacent cartridges fuse together to form large clusters of axons (8 to 10 cartridges). There is further coalescence between these large clusters. Extracellular space within the optic tract is severely limited and axons are sheathed by glial lamellae. Extracellular space between the axons and glia has been measured between 50 and 120 Å. Calculations are presented that suggest that the glial interstices between the axons could increase the space constants of the axons significantly. Potentials could be transmitted along the length of the axons with between 59 to 37 percent decrementai decrease, depending upon the number of glial interstices.     

Development of the eye and optic lobe of Octopus

The development of the lens, retina and optic lobes was followed in Octopus australis and O. pallidus , two species that produce benthic larvae and can readily be reared in the laboratory from egg to adult.
The inner part of the lens starts to form at Naef's stage IX, and consists of a central core with overlying layers formed from processes of the lentigenic cells. Microvilli occur on the surface of the lens, and cilia and microvilli are visible in the retina, which at this point, however, is undifferentiated. The optic lobes have not started to form. The outer part of the lens starts to develop from stage XVI.
Cellular differentiation of the retina, through cell nuclei crossing the basement membrane, starts at stage XV, with rhabdome development occurring from stage XVI onwards. The optic lobes are clearly formed at stage XII, but only start to differentiate and show layering from stage XVI.
At hatching all adult structures are clearly visible, although considerable quantitative changes still occur before the final adult form is reached.
The development of the visual system of Octopus is similar to that of several species of decapod previously reported.     

Using Adeno-associated Virus as a Tool to Study Retinal Barriers in Disease

Müller cells are the principal glial cells of the retina. Their end-feet form the limits of the retina at the outer and inner limiting membranes (ILM), and in conjunction with astrocytes, pericytes and endothelial cells they establish the blood-retinal barrier (BRB). BRB limits material transport between the bloodstream and the retina while the ILM acts as a basement membrane that defines histologically the border between the retina and the vitreous cavity. Labeling Müller cells is particularly relevant to study the physical state of the retinal barriers, as these cells are an integral part of the BRB and ILM. Both BRB and ILM are frequently altered in retinal disease and are responsible for disease symptoms.There are several well-established methods to study the integrity of the BRB, such as the Evans blue assay or fluorescein angiography. However these methods do not provide information on the extent of BRB permeability to larger molecules, in nanometer range. Furthermore, they do not provide information on the state of other retinal barriers such as the ILM. To study BRB permeability alongside retinal ILM, we used an AAV based method that provides information on permeability of BRB to larger molecules while indicating the state of the ILM and extracellular matrix proteins in disease states. Two AAV variants are useful for such study: AAV5 and ShH10. AAV5 has a natural tropism for photoreceptors but it cannot get across to the outer retina when administered into the vitreous when the ILM is intact (i.e., in wild-type retinas). ShH10 has a strong tropism towards glial cells and will selectively label Müller glia in both healthy and diseased retinas. ShH10 provides more efficient gene delivery in retinas where ILM is compromised. These viral tools coupled with immunohistochemistry and blood-DNA analysis shed light onto the state of retinal barriers in disease.     

Immuno-electron microscopical studies on the retinal basement membrane of chick embryo

Retinal basement membrane (RBM), also called inner limiting membrane of retina, is constituted by extracellular matrix. It was reported that neurite outgrowth of a neuron was closely related to extracellular matrix, particularly the laminin. In this laboratory RBM was used as the optimal substrate for retinal cells in culture. We have studied the surface of RBM and its relation to neurite outgrowth by scanning electronmicroscopy and immunogold transmission electronmicroscopy. RBM could be separated by mechanical disruption of the retina mounted between 2 adhesive substrata (membrane filter and poly-L-lysine coated glass). The surface of RBM studied was the side of RBM facing the optic fiber layer and ganglion cell layer. Small particles densely distributed on surface of RBM (Plate I, Fig. 1 and 2) were shown to be chrysanthemum-like structures with radiative arms under the scanning electronmicroscopy (Plate I, Fig. 3 and 4). The radiative arms of RBM of 12-day old chick embryo (E 12) were more in number and longer in length than that of the 6-day old chick embryo (E 6). The axons of ganglion cell from E 6 retinal strip extended out very well on RBM (Plate I, Fig. 5). Growth cone was active with filopodia. The chrysanthemum-like structures changed to ball-particles when the RBM was cultured for 24 hr. Some of ball-particles lay over the growth cone, and some beside it. Over and beside the nerve fiber could also be seen some ball-particles. When many neurites grew on RBM, a lot of ball-particles were shown to be displaced and piled up (Plate I, Fig. 6). The whole amount RBM labeled by indirect immunogold staining of Müller glial cell could be observed by transmission electronmicroscopy. The gold particles wer located at the chrysanthemum-like structure of E 6 RBM (Plate II, Fig. 7) and E 12 RBM (Plate II, Fig. 8). It was suggested that those structures were the end foot of Müller glial cells. Staining of PBS control or mouse serum control was negative (Plate II, Fig. 9 and 10).(ABSTRACT TRUNCATED AT 250 WORDS)     

The glial design of a teleost optic nerve head supporting continuous growth.

This study demonstrates the peculiarities of the glial organization of the optic nerve head (ONH) of a fish, the tench (Tinca tinca), by using immunohistochemistry and electron microscopy. We employed antibodies specific for the macroglial cells: glutamine synthetase (GS), glial fibrillary acidic protein (GFAP), and S100. We also used the N518 antibody to label the new ganglion cells' axons, which are continuously added to the fish retina, and the anti-proliferating cell nuclear antigen (PCNA) antibody to specifically locate dividing cells. We demonstrate a specific regional adaptation of the GS-S100-positive Müller cells' vitreal processes around the optic disc, strongly labeled with the anti-GFAP antibody. In direct contact with these Müller cells' vitreal processes, there are S100-positive astrocytes and S100-negative cells ultrastructurally identified as microglial cells. Moreover, a population of PCNA-positive cells, characterized as glioblasts, forms the limit between the retina and the optic nerve in a region homologous to the Kuhnt intermediary tissue of mammals. Finally, in the intraocular portion of the optic nerve there are differentiating oligodendrocytes arranged in rows. Both the glioblasts and the rows of developing cells could serve as a pool of glial elements for the continuous growth of the visual system.     

Electron microscopy of the mucosal plexus of the rat colon.

The ultrastructure of neurons, glial cells and axons of the mucosal plexus of the rat colon descendens was studied. Serial semithin sections and a re-embedding technique were used in order to localize the ganglia. The ganglia are free of blood vessels and connective tissue. The ratio of neurons to glial cells is approximately 1. Ganglia and nerve strands are enclosed by a basement membrane, without a well-defined perineural connective tissue. The neurons show a structure similar to other enteric plexus. Synaptic contacts were observed frequently in the neuropil, where nerve endings and varicosities show a diverse outfit in vesicles. The glial cells, which contain immunocytochemically detectable glial fibrillary protein, possess the same ultrastructural attributes in the intra- and extraganglionic localizations. In the nerves, axonic profiles and varicosities appear in close relation with glial cells or their processes. The distance between the nerves and their target cells, i.e. the enterocytes, is 0.5 microns or more with interposed basement membranes and fibroblasts.     

Glial cells of the crayfish and their relationships with neurons. An ultrastructural study

1. Glial cells of the crayfish abdominal ganglia have been studied by transmission electron microscopy. Special attention is paid to the interrelationships between neurons and glial cells. Covers and hemocyte-related elements have also been considered. 2. Glial cells are identified by a common ultrastructure and close relationships with neurons. Four glial classes are considered, depending on their morphology, the compartment of neurons they ensheathe and neuron-glia interface. 3. Four ultrastructural classes of neurons are proposed. They differ in geometry and ultrastructure, as well as in glial covers (complexity and evaginations into the neuron somata). The morphology and organization of glial covers is specific for the neuron type they ensheathe. Specific glial covers do not differ in glia-glia communicatory structures. 4. The morphological and metabolical compartments of neurons are separated from the extracellular matrix or blood by specific glial systems. A system of two cells is interposed between neuron somata and hemolymph or the extracellular matrix. 5. Glial processes are crossed by membraneous tubular systems, at neuron perikarya and axons. Frequent gap junctions of varying area, density and number of IMP are found in the covers of neuron somata. 6. Neuron-glia interface bears numerous communicatory structures for both ionic and macromolecular exchange. They include junctions and transient modifications of membranes. Some of them suggest active transport mechanisms. 7. Modified endocytotic mechanisms seem to be responsible for the glia-to-neuron transfer of macromolecules as well as for the neuron-to-glia transfer of lamellar bodies. 8. The neuropil is divided into glomeruli (electrical or chemical) by glial processes and the trabeculae of the extracellular dense matrix. Neuron-glia membrane appositions have been found in electrical glomeruli. In chemical glomeruli, dense cored vesicles can release their content at neuron-neuron or neuron-glia intercellular cleft, at non-synaptic loci. 9. Neurons of type II contain peripheral complex Golgi systems, associated to subsurface cisternae and neuron-glia gap junctions, suggesting a cooperation of glial cells in specific macromolecular synthesis.     

The basement membrane of the insect and crustacean compound eye: Definition,fine structure,and comparative morphology

Summary The basement membrane of the compound eye of four insect species and three crustacean species was investigated employing electron microscopy. The basement membrane consists of an extracellular (basal lamina) and a cellular portion, the latter being composed of the flattened terminal extensions of cone cells and accessory pigment cells in insects and distal pigment cells in crustaceans. Other cells can also contribute to the basement membrane. It is thus a complex structure in all well-developed compound eyes. The cellular contributions vary in different species and were found to correlate to specific taxonomic units.     

Etiology of the developing eye in myelencephalic blebs (my) mice.

The etiology of the eye defects in myelencephalic blebs (my) mutant mice has been poorly understood for almost seventy years. Embryos from 9 to 14 1/2 days of gestation were subjected to Alcian blue 8GX staining for acidic glycosaminoglycan deposition in basement membrane structures of the developing eye in my stock and control specimens. In addition 12 day embryos were subjected to avidinbiotin-peroxidase labelling for laminin. At 9-9 1/2 days of gestation more Alcian blue positive extracellular matrix was found in the region between the optic vesicle and the overlying putative lens ectoderm in the my stock embryos. By 12 days, there was an irregular and lesser amount of deposition of glycosaminoglycans in the len's capsule and in the "inner limiting membrane" of the presumptive neural retina; however, the deposition of laminin appeared to be greater in the inner limiting membrane of the my eye. By 14 days, the damage to the eye in the my embryos can be quite extensive, and the deposition of glycosaminoglycans was very meager in this situation. It appears that irregular deposition of glycosaminoglycans in the extracellular matrix and possible increase in the amount of laminin in basement structures in my embryos indicate disruption of the normal histochemistry involved in the development of the eye. Altered histochemistry may in turn indicate changes in permeability between cells of the developing tissues which result in the blebbing.     

Distribution of laminin in the developing peripheral nervous system of the chick

During axonal elongation in the developing peripheral nervous system, the temporal and spatial distribution of adhesive molecules in extracellular matrices and on neighboring cell surfaces may provide "choices" of pathways for growth cone migration. The extracellular matrix glycoprotein laminin appears in early embryos and mediates neuronal adhesion and neurite extension in vitro. In this study, we have examined the distribution of laminin at early periods of peripheral nervous system development. The distribution of laminin, demonstrated by immunostaining frozen sections of chick embryos, was compared to the distribution of fibronectin and of early peripheral neurites as revealed with an antibody to a neurofilament-associated protein. Laminin is present in the neural tube basement membrane, in early ganglia, and in developing dorsal and ventral roots, where the laminin staining pattern parallels that of neurofilaments. In early ganglia and nerve roots, laminin immunostaining defines loose "meshworks" rather than basement membranes, which seem to form slightly later in these structures. In contrast, fibronectin is absent in neural tube basement membrane, ganglia, and nerve roots, although it is present along neural crest migratory pathways and in intersomitic spaces. Our observations of laminin distribution are consistent with the possibility that laminin provides an adhesive surface for neurite extension at some stages of early peripheral nervous system development.     

The fine structure of the retina of the honey bee drone

Summary The eye of the honey bee drone is composed of approximately 8,000 photoreceptive units or ommatidia, each topped by a crystalline cone and a corneal facet. An ommatidium contains 9 visual or retinula cells whose processes or axons pierce a basement membrane and enter the optic lobe underlying the sensory retina. The visual cells of the ommatidium are of unequal size: six are large and three, small. In the center of the ommatidium, the visual cells bear a brush of microvilli called rhabdomere. The rhabdome is a closed-type one and formed mainly by the rhabdomeres of the six large retinula cells. The rhabdomeric microvilli probably contain the photopigment (rhodopsin), whose modification by light lead to the receptor potential in the retinula cells. The cytoplasm of the retinula cells contains various organelles including pigment granules (ommochromes), and peculiar structures called the subrhabdomeric cisternae. The cisternae, probably composed of agranular endoplasmic reticulum undergo swelling during dark adaptation and appear in frequent connection with Golgi cisternae. Three types of pigment cells are associated with each ommatidium. The crystalline cone is entirely surrounded by two corneal pigment cells. The ommatidium, including its dioptric apparatus and corneal pigment cells, is surrounded by a sleeve of about 30 elongated cells called the outer pigment cells. These extend from the base of the corneal facet to the basement membrane. Near the basement membrane the center of the ommatidium is occupied by a basal pigment cell. Open extracellular channels are present between pigment cells as well as between retinula cells. Tight junctions within the ommatidium are restricted to the contact points between the rhabdomeric microvilli. These results are discussed in view of their functional implications in the drone vision, as well as in view of the data of comparative morphology.This work was supported by a grant from the Fonds National Suisse de la Recherche Scientifique.     

Structure of visual pathways in the nervous system of fresh water pulmonary molluscs

The central nervous system of freshwater pulmonary molluscs Lymnaea stagnalis and Planorbarins corneus was stained by the method of neurobiotin retrograde transport along optic nerve fibers. In the animals of both species, bodies and fibers of stained neurons are found in all ganglia except for the buccal ones. Afferent fibers of the optic nerve form a dense sensor neuropil located in a small volume of cerebral ganglia. Characteristic groups of neurons sending their processes into optic nerves both of ipsi- and of contralateral half of the body are described. Revealed among them are neurons of visceral and parietal ganglia, which simultaneously innervate both eyes as well as give projections into peripheral nerves. It is suggested that these neurons can perform function of integration of sensor signals and, on its base, regulate photosensitivity of retina as well as activity of peripheral organs. There is established the presence of bilateral connections of the mollusc eye with cells of pedal ganglia and statocysts, which seems to be the structural basis of manifestation of the known behavior forms associated with stimulation of visual inputs of the studied gastropod molluscs.     

The effect of extracellular matrix interactions on morphologic transformation in vitro

There is emerging evidence that the structure and function of a cell is dependent in part on the contacts that cells make with the extracellular matrix. We report here the effect of extracellular matrices secreted from both normal and tumor cells have on the structure of normal rat kidney epithelial cells. Normal rat kidney cells plated on the basement membrane secreted by tumor cells adopt a morphology and phenotype which closely resembles a Kirsten-ras transformed normal rat kidney cell. This morphologic transformation was not observed for cells plated on individual extracellular matrix components or on basement membrane secreted by normal placenta cells. This suggests that tumor derived basement membrane has unique characteristics which may cause morphologic transformation of normal rat kidney cells.     

Histochemical localization of protein-polysaccharides in renal tissue

The purpose of this study was to investigate the distribution of protein-polysaccharides in the glomerular and non-glomerular regions of the nephron. The techniques used include the digestion of kidney slices with specific polysaccharidases: neuraminidase, hyaluronidase, chondroitinase ABC, and collagenase followed by several cytochemical techniques to identify the glycosaminoglycans and glycoproteins at the light and electron microscope levels. Differential staining of hyaluronic acid and sulphated glycosaminoglycans was accomplished with Alcian Blue at pH 2.5 and pH 0.5, respectively. Sialoproteins were stained with Alcian Blue at pH 2.5. The periodic acid Schiff’s reaction technique was employed for the visualization of collagen. At the electron microscope level the polysaccharides were identified with the periodic acid-chromic acid-silver methenamine reaction. Our results indicated that the major polysaccharide components of the glomerular basement membrane were sialoproteins and collagen, with smaller amounts of hyaluronic acid and various sulphated glycosaminoglycans. Hyaluronidase digestion resulted in partial detachment of epithelial processes from the glomerular basement membrane indicating the hyaluronic acid may have a role in the stability of the attachment of these processes. Tubular basement membranes also contain sialoproteins and sulphated glycosaminoglycans but in considerably lower concentrations than the glomerular basement membrane. Bowman’s capsule appears to contain mostly sulphated glycosaminoglycans and has a lower concentration of sialoproteins and hyaluronic acid.     

Two visual systems in one eyestalk: The unusual optic lobe metamorphosis in the stomatopod Alima pacifica

The compound eyes of adult stomatopod crustaceans have two to six ommatidial rows at the equator, called the midband, that are often specialized for color and polarization vision. Beneath the retina, this midband specialization is represented as enlarged optic lobe lamina cartridges and a hernia‐like expansion in the medulla. We studied how the optic lobe transforms from the larvae, which possess typical crustacean larval compound eyes without a specialized midband, through metamorphosis into the adults with the midband in a two midband‐row species Alima pacifica. Using histological staining, immunolabeling, and 3D reconstruction, we show that the last‐stage stomatopod larvae possess double‐retina eyes, in which the developing adult visual system forms adjacent to, but separate from, the larval visual system. Beneath the two retinas, the optic lobe also contains two sets of optic neuropils, comprising of a larval lamina, medulla, and lobula, as well as an adult lamina, medulla, and lobula. The larval eye and all larval optic neuropils degenerate and disappear approximately a week after metamorphosis. In stomatopods, the unique adult visual system and all optic neuropils develop alongside the larval system in the eyestalk of last‐stage larvae, where two visual systems and two independent visual processing pathways coexist. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 3–14, 2018