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P Fernandezllebrez - One of the best experts on this subject based on the ideXlab platform.
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the Subcommissural Organ and the development of the posterior commissure
International Review of Cell and Molecular Biology, 2012Co-Authors: J M Grondona, P Fernandezllebrez, Carolina Hoyobecerra, Rick Visser, Maria Dolores LopezavalosAbstract:Abstract Growing axons navigate through the developing brain by means of axon guidance molecules. Intermediate targets producing such signal molecules are used as guideposts to find distal targets. Glial, and sometimes neuronal, midline structures represent intermediate targets when axons cross the midline to reach the contralateral hemisphere. The Subcommissural Organ (SCO), a specialized neuroepithelium located at the dorsal midline underneath the posterior commissure, releases SCO-spondin, a large glycoprotein belonging to the thrombospondin superfamily that shares molecular domains with axonal pathfinding molecules. Several evidences suggest that the SCO could be involved in the development of the PC. First, both structures display a close spatiotemporal relationship. Second, certain mutants lacking an SCO present an abnormal PC. Third, some axonal guidance molecules are expressed by SCO cells. Finally, SCO cells, the Reissner's fiber (the aggregated form of SCO-spondin), or synthetic peptides from SCO-spondin affect the neurite outgrowth or neuronal aggregation in vitro.
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hydrocephalus and abnormal Subcommissural Organ in mice lacking presenilin 1 in wnt1 cell lineages
Brain Research, 2011Co-Authors: Mitsunari Nakajima, Juan Pérez, P Fernandezllebrez, Keiko Matsuda, Naho Miyauchi, Yasuyoshi Fukunaga, Sono Watanabe, Satoshi Okuyama, Jie Shen, Yoshiko FurukawaAbstract:Abstract Presenilin-1 (PS1) is a transmembrane protein that is in many cases responsible for the development of familial Alzheimer's disease. PS1 is widely expressed in embryogenesis and is essential for neurogenesis, somitogenesis, angiogenesis, and cardiac morphogenesis. To further investigate the role of PS1 in the brain, we inactivated the PS1 gene in Wnt1 cell lineages using the Cre–loxP recombination system. Here we show that conditional inactivation of PS1 in Wnt1 cell lineages results in congenital hydrocephalus and Subcommissural Organ abnormalities, suggesting a possible role of PS1 in the regulation of cerebrospinal fluid homeostasis.
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the Subcommissural Organ of the frog rana perezi is innervated by nerve fibres containing gaba
Cell and Tissue Research, 2000Co-Authors: Antonio J Jimenez, J M Perezfigares, Margarita Perezmartin, M I Aller, R Martin, Arsenio Fernandezlopez, P FernandezllebrezAbstract:The innervation of the frog Subcommissural or- gan was studied by light-microscopic and ultrastructural immunocytochemistry using antisera against serotonin, noradrenaline, dopamine, γ-aminobutyric acid (GABA), glutamic acid decarboxylase, different GABA receptor subunits and bovine Reissner's fibre material (AFRU). In the proximity of the Organ, serotonin- and noradrenaline- containing fibres were rare whereas dopamine-immuno- reactive fibres were more numerous. Many GABA- and glutamic acid decarboxylase-containing nerve fibres were found at the basal portion of the ependymal cells of the Subcommissural Organ. Under the electron microscope, these GABA-immunolabelled nerve endings appeared to establish axoglandular synapses with secretory ependy- mal cells of the Subcommissural Organ. In addition, the secretory ependymal cells expressed high amounts of the β2-subunit of the GABAA receptor. Since GABA-immu- noreactive neurons were present in the frog pineal Organ proper and apparently contributed axons to the pineal tract, we suggest that at least part of the GABAergic fi- bres innervating the frog Subcommissural Organ could originate from the pineal Organ.
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floor plate and the Subcommissural Organ are the source of secretory compounds of related nature comparative immunocytochemical study
The Journal of Comparative Neurology, 1998Co-Authors: Carlos R Yulis, Sara Rodriguez, J A Andrades, Bruno Peruzzo, M D Mota, Juan Miguel Mancera, P Ramirez, M Garrido, J M Perezfigarez, P FernandezllebrezAbstract:The Subcommissural Organ of vertebrates secretes glycoproteins into the third ventricle that condense to form Reissner’s fiber (RF). Antibodies raised against the bovine RFglycoproteins reacted with the floor plate (FP) cells of two teleost (Oncorhynchus kisutch, Sparus aurata) and two amphibian (Xenopus laevis, Batrachyla taeniata) species. At the ultrastructural level, the immunoreactivity was confined to secretory granules, mainly concentrated at the apical cell pole. In the rostro-caudal axis, a clear zonation of the FP was distinguished, with the hindbrain FP being the most, or the only (Batrachyla taeniata), immunoreactive region of the FP. In all the species studied, the caudal FP lacked immunoreactivity. Both the chemical nature of the immunoreactive material and the rostro-caudal zonation of the FP appear to be conservative features. Evidence was obtained that the FP secretes into the cerebrospinal fluid a material chemically related to the RF-glycoproteins secreted by the Subcommissural Organ. Thus, in addition to being the source of contactmediated and diffusible signals, the FP might also secrete compounds into the cerebrospinal fluid
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spontaneous congenital hydrocephalus in the mutant mouse hyh changes in the ventricular system and the Subcommissural Organ
Journal of Neuropathology and Experimental Neurology, 1998Co-Authors: J M Perezfigares, Manuel Cifuentes, P Fernandezllebrez, Antonio J Jimenez, Margarita Perezmartin, P Riera, Sara Rodriguez, E M RodriguezAbstract:: The Subcommissural Organ is an ependymal gland located at the entrance of the cerebral aqueduct. It secretes glycoproteins into the cerebrospinal fluid, where they aggregate to form Reissner's fiber. This fiber grows along the aqueduct, fourth ventricle, and central canal. There is evidence that the Subcommissural Organ is involved in the pathogenesis of congenital hydrocephalus. This Organ was investigated in the mutant mouse hyh developing a congenital hydrocephalus. The central nervous system of normal and hydrocephalic hyh mice, 1 to 40 days old, was investigated using antibodies recognizing the Subcommissural Organ secretory glycoproteins, and by transmission and scanning electron microscopy. At birth, the affected mice displayed open communications between all ventricles, absence of a central canal in the spinal cord, ependymal denudation of the ventricles, stenosis of the rostral end of the aqueduct, and hydrocephalus of the lateral and third ventricles and of the caudal end of the aqueduct. Around the 5th postnatal day, the communication between the caudal aqueduct and fourth ventricle sealed, and hydrocephalus became severe. It is postulated that the hyh mice carry a genetic defect affecting the ependymal cell lineage. The Subcommissural Organ showed signs of increased secretory activity; it released to the stenosed aqueduct a material that aggregated, but it did not form a Reissner's fiber. A large area of the third ventricular wall differentiated into a secretory ependyma synthesizing a material similar to that secreted by the Subcommissural Organ. It is concluded that the Subcommissural Organ changes during hydrocephalus; whether these changes precede hydrocephalus needs to be investigated.
Annie Meiniel - One of the best experts on this subject based on the ideXlab platform.
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the secretory ependymal cells of the Subcommissural Organ which role in hydrocephalus
The International Journal of Biochemistry & Cell Biology, 2007Co-Authors: Annie MeinielAbstract:Abstract Ependyma in the central nervous system gives rise to several specialized cell types, including the secretory ependymal cells located in the Subcommissural Organ. These elongated cells show large cisternae in their cytoplasm, which are filled with material secreted into the cerebrospinal fluid and toward the leptomeningeal spaces. A specific secretion of the Subcommissural Organ was named SCO-spondin, regarding its marked homology with developmental proteins of the thrombospondin superfamily (presence of thrombospondin type 1 repeats). The ependymal cells of the Subcommissural Organ and SCO-spondin secretion are suspected to play a crucial role in cerebrospinal fluid flow and/or homeostasis. There is a close correlation between absence of the Subcommissural Organ and hydrocephalus in rat and mouse strains exhibiting congenital hydrocephalus, and in a number of mice transgenic for developmental genes. The ependymal cells of the Subcommissural Organ are under research as a key factor in several developmental processes of the central nervous system.
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Purified secretory glycoproteins of the bovine Subcommissural Organ influence neuronal differentiation in vitro
The International Journal of Developmental Biology, 2001Co-Authors: Elena Miranda, Juan Pérez, Pedro Fernández-llebrez, Machid Bamdad, Carolina Hoyo, Annie MeinielAbstract:The Subcommissural Organ-spondin (SCO-spondin), a glycoprotein belonging to the thrombospondin family, is secreted by specialyzed cells located at the floor and roof plates during the ontogenetic development of the central nervous system, and by the Subcommissural Organ (SCO) in adulthood. The intracellular secretion of the bovine SCO was purified by immunoaffinity chromatography with monoclonal antibodies raised against the Reissner's fiber (RF), a fibrous structure present at the ventricular cavities and that results from the polymerization of the SCO-spondin apically released by the SCO secretory cells. The purified secretion was used as a SCO-spondin source and assayed on cultures of the rat neuroblastoma B104 cell line. High doses of SCO secretory glucoproteins inhibited the proliferation of cultured neuroblasts, while lower concentrations stimulated neurite outgrowth and cellular aggregation.
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secretory activity and serotonin innervation of lizard s Subcommissural Organ
Neuroreport, 2000Co-Authors: Samir Ahboucha, Annie Meiniel, M Didierbazes, Michelle Fevremontange, Halima GamraniAbstract:: We investigated immunohistochemically the Subcommissural Organ (SCO) glycoprotein secretion, its serotoninergic (5-HT) innervation and the possible control of this innervation upon the SCO activity in lizards (Agama impalearis, Saurodactylus mauritanicus and Eumeces algeriensis). Inside the SCO, interspecific differences in the intensity and the distribution of both secretory product and 5-HT nerve fibers were observed. Compared with Agama and Eumeces, the SCO of Saurodactylus displayed intense secretory products and several 5-HT fibers. In Saurodactylus, i.p. injection of parachlorophenylalanine, a potent inhibitor of 5-HT synthesis, produced a marked decrease of SCO secretory product. We report in this study species differences of the lizard SCO secretory activity and its possible physiological control by 5-HT innervation, as previously demonstrated in mammals.
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Secretory activity and serotonin innervation of Subcommissural Organ.
Neuroreport, 2000Co-Authors: Samir Ahboucha, Annie Meiniel, Marianne Didler-bazes, Michelle Fèvre-montange, Halima GamraniAbstract:: We investigated immunohistochemically the Subcommissural Organ (SCO) glycoprotein secretion, its serotoninergic (5-HT) innervation and the possible control of this innervation upon the SCO activity in lizards (Agama impalearis, Saurodactylus mauritanicus and Eumeces algeriensis). Inside the SCO, interspecific differences in the intensity and the distribution of both secretary product and 5-HT nerve fibers were observed. Compared with Agama and Eumeces, the SCO of Saurodactylus displayed intense secretory products and several 5-HT fibers. In Saurodactylus, i.p. injection of parachlorophenylalanine, a potent inhibitor of 5-HT synthesis, produced a marked decrease of SCO secretory product. We report in this study species differences of the lizard SCO secretory activity and its possible physiological control by 5-HT innervation, as previously demonstrated in mammals.
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specific transcripts analysed by in situ hybridization in the Subcommissural Organ of bovine embryos
Cell and Tissue Research, 1995Co-Authors: Robert Meiniel, Isabelle Creveaux, Bernard Dastugue, Annie MeinielAbstract:The Subcommissural Organ (SCO) secretes specific glycoproteins into the cerebrospinal fluid that aggregate to constitute Reissner's fiber (RF), a thread-like structure running along the central canal of the spinal cord. For further identification of the gene(s) encoding these secretions, we have prepared a cDNA library in the vector IGT11 from bovine embryonic SCO. The screening of this library was performed using a polyclonal antibody raised against bovine RF. Three positive clones were isolated and purified and one of these λRF101 comprising an insert of #400 nucleotides was undercloned into pBluescript plasmid and mapped. After labeling with 35S (ATP) this cDNA fragment served as a probe to analyse the presence of specific transcripts in the Subcommissural Organ of the embryonic bovine by in situ hybridization. A labeling signal was observed in the embryonic SCO both in the secretory ependymal and hypendymal cells. This labeling is specific since the ependymal layer bordering the ventricular cavity as well as the surrounding nervous tissue remained negative. Thus, the embryonic SCO contains specific transcripts that are colocalized with the specific glycoproteins as shown after the use of a specific monoclonal antibody C1B8A8. In addition, the pattern of labeling with the specific SCO cDNA is different from those of β actin cDNA and tear lipocalin cDNA, which, respectively, served as positive and negative controls. In a subsequent set of experiments the expression pattern was compared in embryos at two different stages of development (4-month-old and 8-month-old embryos). No difference in the intensity of labeling could be detected in the SCO of both stages suggesting that the level of expression remains stable at least during the second part of gestation. The identification of the complete cDNA sequence is now required to find out homologies with known factors and to provide information about the role of these proteins in the developing nervous system.
Juan Pérez - One of the best experts on this subject based on the ideXlab platform.
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hydrocephalus and abnormal Subcommissural Organ in mice lacking presenilin 1 in wnt1 cell lineages
Brain Research, 2011Co-Authors: Mitsunari Nakajima, Juan Pérez, P Fernandezllebrez, Keiko Matsuda, Naho Miyauchi, Yasuyoshi Fukunaga, Sono Watanabe, Satoshi Okuyama, Jie Shen, Yoshiko FurukawaAbstract:Abstract Presenilin-1 (PS1) is a transmembrane protein that is in many cases responsible for the development of familial Alzheimer's disease. PS1 is widely expressed in embryogenesis and is essential for neurogenesis, somitogenesis, angiogenesis, and cardiac morphogenesis. To further investigate the role of PS1 in the brain, we inactivated the PS1 gene in Wnt1 cell lineages using the Cre–loxP recombination system. Here we show that conditional inactivation of PS1 in Wnt1 cell lineages results in congenital hydrocephalus and Subcommissural Organ abnormalities, suggesting a possible role of PS1 in the regulation of cerebrospinal fluid homeostasis.
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Purified secretory glycoproteins of the bovine Subcommissural Organ influence neuronal differentiation in vitro
The International Journal of Developmental Biology, 2001Co-Authors: Elena Miranda, Juan Pérez, Pedro Fernández-llebrez, Machid Bamdad, Carolina Hoyo, Annie MeinielAbstract:The Subcommissural Organ-spondin (SCO-spondin), a glycoprotein belonging to the thrombospondin family, is secreted by specialyzed cells located at the floor and roof plates during the ontogenetic development of the central nervous system, and by the Subcommissural Organ (SCO) in adulthood. The intracellular secretion of the bovine SCO was purified by immunoaffinity chromatography with monoclonal antibodies raised against the Reissner's fiber (RF), a fibrous structure present at the ventricular cavities and that results from the polymerization of the SCO-spondin apically released by the SCO secretory cells. The purified secretion was used as a SCO-spondin source and assayed on cultures of the rat neuroblastoma B104 cell line. High doses of SCO secretory glucoproteins inhibited the proliferation of cultured neuroblasts, while lower concentrations stimulated neurite outgrowth and cellular aggregation.
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rostral floor plate flexural Organ secretes glycoproteins immunologically similar to Subcommissural Organ glycoproteins in dogfish scyliorhinus canicula embryos
Developmental Brain Research, 1997Co-Authors: M D Lopezavalos, Manuel Cifuentes, Juan Pérez, J M Grondona, Elena Miranda, P FernandezllebrezAbstract:Abstract The Subcommissural Organ of vertebrates secretes glycoproteins into the cerebrospinal fluid of the third cerebral ventricle. This material polymerizes in Reissner's fiber. During ontogenetic development, besides the Subcommissural Organ, the ependyma lining the pontine flexure constitutes an additional Reissner's fiber-secreting gland named flexural Organ. We have studied the secretion of the flexural Organ and the Subcommissural Organ in dogfish (Scyliorhinus canicula) embryos using three different antisera and the lectins concanavalin A and wheat germ agglutinin. AFRU is an antiserum against the bovine Reissner's fiber; Ab-600 is an antiserum against 600 kDa dogfish Subcommissural Organ glycoproteins; and APSO is an antiserum against immunoaffinity purified bovine Subcommissural Organ secretory glycoproteins. These three antisera immunostained the flexural Organ indicating that it contains epitopes similar to those present in bovine and dogfish Subcommissural Organ glycoproteins. It seems highly probable that the flexural Organ and the Subcommissural Organ of dogfish embryos secrete similar compound(s). Other ependymal regions were also immunostained with Ab-600 and APSO antisera. Then, Reissner's fiber-like glycoproteins were transiently expressed by most embryonary ependymal cells. These glycoproteins might play a role in the development of the central nervous system of vertebrates.
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Rostral floor plate flexural Organ secretes glycoproteins immunologically similar to Subcommissural Organ glycoproteins in / dogfish Scyliorhinus canicula embryos
Developmental Brain Research, 1997Co-Authors: M. D. López-avalos, Manuel Cifuentes, Juan Pérez, Jesús M. Grondona, Elena Miranda, Pedro Fernández-llebrezAbstract:Abstract The Subcommissural Organ of vertebrates secretes glycoproteins into the cerebrospinal fluid of the third cerebral ventricle. This material polymerizes in Reissner's fiber. During ontogenetic development, besides the Subcommissural Organ, the ependyma lining the pontine flexure constitutes an additional Reissner's fiber-secreting gland named flexural Organ. We have studied the secretion of the flexural Organ and the Subcommissural Organ in dogfish (Scyliorhinus canicula) embryos using three different antisera and the lectins concanavalin A and wheat germ agglutinin. AFRU is an antiserum against the bovine Reissner's fiber; Ab-600 is an antiserum against 600 kDa dogfish Subcommissural Organ glycoproteins; and APSO is an antiserum against immunoaffinity purified bovine Subcommissural Organ secretory glycoproteins. These three antisera immunostained the flexural Organ indicating that it contains epitopes similar to those present in bovine and dogfish Subcommissural Organ glycoproteins. It seems highly probable that the flexural Organ and the Subcommissural Organ of dogfish embryos secrete similar compound(s). Other ependymal regions were also immunostained with Ab-600 and APSO antisera. Then, Reissner's fiber-like glycoproteins were transiently expressed by most embryonary ependymal cells. These glycoproteins might play a role in the development of the central nervous system of vertebrates.
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Identification of a high molecular weight polypeptide in the Subcommissural Organ of the chick embryo
Cell and Tissue Research, 1996Co-Authors: Manuel Cifuentes, M. D. López-avalos, Juan Pérez, Jesús M. Grondona, Pedro Fernández-llebrezAbstract:The Subcommissural Organ is an ependymal brain gland that secretes, into the ventricular cerebrospinal fluid, high molecular weight glycoproteins that form Reissner’s fiber. Precursor and processed forms of secretion have been demonstrated by immunoblotting in the Subcommissural Organ of mammals and fish. In the chicken only a processed form has as yet been identified. In the present report, we have studied the Subcommissural Organ of 13-day-old chick embryos using (1) an antiserum against bovine Reissner’s fiber, and (2) the lectins, concanavalin A and Limax flavus agglutinin. Paraffin sections of the Subcommissural Organ and blots of Subcommissural Organ extracts have been analyzed. The ependymal cells of sectioned Subcommissural Organ are strongly stained with the antiserum. Concanavalin A binds to materials in all cytoplasmatic regions, whereas Limax flavus agglutinin identifies materials confined to the apex of the ependymal cells. In the blots, a band of 540 kDa is immunostained. This band is positive for concanavalin A positive but negative for Limax flavus agglutinin and is thereby regarded as representing a precursor form of the secretion.
Manuel Cifuentes - One of the best experts on this subject based on the ideXlab platform.
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spontaneous congenital hydrocephalus in the mutant mouse hyh changes in the ventricular system and the Subcommissural Organ
Journal of Neuropathology and Experimental Neurology, 1998Co-Authors: J M Perezfigares, Manuel Cifuentes, P Fernandezllebrez, Antonio J Jimenez, Margarita Perezmartin, P Riera, Sara Rodriguez, E M RodriguezAbstract:: The Subcommissural Organ is an ependymal gland located at the entrance of the cerebral aqueduct. It secretes glycoproteins into the cerebrospinal fluid, where they aggregate to form Reissner's fiber. This fiber grows along the aqueduct, fourth ventricle, and central canal. There is evidence that the Subcommissural Organ is involved in the pathogenesis of congenital hydrocephalus. This Organ was investigated in the mutant mouse hyh developing a congenital hydrocephalus. The central nervous system of normal and hydrocephalic hyh mice, 1 to 40 days old, was investigated using antibodies recognizing the Subcommissural Organ secretory glycoproteins, and by transmission and scanning electron microscopy. At birth, the affected mice displayed open communications between all ventricles, absence of a central canal in the spinal cord, ependymal denudation of the ventricles, stenosis of the rostral end of the aqueduct, and hydrocephalus of the lateral and third ventricles and of the caudal end of the aqueduct. Around the 5th postnatal day, the communication between the caudal aqueduct and fourth ventricle sealed, and hydrocephalus became severe. It is postulated that the hyh mice carry a genetic defect affecting the ependymal cell lineage. The Subcommissural Organ showed signs of increased secretory activity; it released to the stenosed aqueduct a material that aggregated, but it did not form a Reissner's fiber. A large area of the third ventricular wall differentiated into a secretory ependyma synthesizing a material similar to that secreted by the Subcommissural Organ. It is concluded that the Subcommissural Organ changes during hydrocephalus; whether these changes precede hydrocephalus needs to be investigated.
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rostral floor plate flexural Organ secretes glycoproteins immunologically similar to Subcommissural Organ glycoproteins in dogfish scyliorhinus canicula embryos
Developmental Brain Research, 1997Co-Authors: M D Lopezavalos, Manuel Cifuentes, Juan Pérez, J M Grondona, Elena Miranda, P FernandezllebrezAbstract:Abstract The Subcommissural Organ of vertebrates secretes glycoproteins into the cerebrospinal fluid of the third cerebral ventricle. This material polymerizes in Reissner's fiber. During ontogenetic development, besides the Subcommissural Organ, the ependyma lining the pontine flexure constitutes an additional Reissner's fiber-secreting gland named flexural Organ. We have studied the secretion of the flexural Organ and the Subcommissural Organ in dogfish (Scyliorhinus canicula) embryos using three different antisera and the lectins concanavalin A and wheat germ agglutinin. AFRU is an antiserum against the bovine Reissner's fiber; Ab-600 is an antiserum against 600 kDa dogfish Subcommissural Organ glycoproteins; and APSO is an antiserum against immunoaffinity purified bovine Subcommissural Organ secretory glycoproteins. These three antisera immunostained the flexural Organ indicating that it contains epitopes similar to those present in bovine and dogfish Subcommissural Organ glycoproteins. It seems highly probable that the flexural Organ and the Subcommissural Organ of dogfish embryos secrete similar compound(s). Other ependymal regions were also immunostained with Ab-600 and APSO antisera. Then, Reissner's fiber-like glycoproteins were transiently expressed by most embryonary ependymal cells. These glycoproteins might play a role in the development of the central nervous system of vertebrates.
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Rostral floor plate flexural Organ secretes glycoproteins immunologically similar to Subcommissural Organ glycoproteins in / dogfish Scyliorhinus canicula embryos
Developmental Brain Research, 1997Co-Authors: M. D. López-avalos, Manuel Cifuentes, Juan Pérez, Jesús M. Grondona, Elena Miranda, Pedro Fernández-llebrezAbstract:Abstract The Subcommissural Organ of vertebrates secretes glycoproteins into the cerebrospinal fluid of the third cerebral ventricle. This material polymerizes in Reissner's fiber. During ontogenetic development, besides the Subcommissural Organ, the ependyma lining the pontine flexure constitutes an additional Reissner's fiber-secreting gland named flexural Organ. We have studied the secretion of the flexural Organ and the Subcommissural Organ in dogfish (Scyliorhinus canicula) embryos using three different antisera and the lectins concanavalin A and wheat germ agglutinin. AFRU is an antiserum against the bovine Reissner's fiber; Ab-600 is an antiserum against 600 kDa dogfish Subcommissural Organ glycoproteins; and APSO is an antiserum against immunoaffinity purified bovine Subcommissural Organ secretory glycoproteins. These three antisera immunostained the flexural Organ indicating that it contains epitopes similar to those present in bovine and dogfish Subcommissural Organ glycoproteins. It seems highly probable that the flexural Organ and the Subcommissural Organ of dogfish embryos secrete similar compound(s). Other ependymal regions were also immunostained with Ab-600 and APSO antisera. Then, Reissner's fiber-like glycoproteins were transiently expressed by most embryonary ependymal cells. These glycoproteins might play a role in the development of the central nervous system of vertebrates.
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Identification of a high molecular weight polypeptide in the Subcommissural Organ of the chick embryo
Cell and Tissue Research, 1996Co-Authors: Manuel Cifuentes, M. D. López-avalos, Juan Pérez, Jesús M. Grondona, Pedro Fernández-llebrezAbstract:The Subcommissural Organ is an ependymal brain gland that secretes, into the ventricular cerebrospinal fluid, high molecular weight glycoproteins that form Reissner’s fiber. Precursor and processed forms of secretion have been demonstrated by immunoblotting in the Subcommissural Organ of mammals and fish. In the chicken only a processed form has as yet been identified. In the present report, we have studied the Subcommissural Organ of 13-day-old chick embryos using (1) an antiserum against bovine Reissner’s fiber, and (2) the lectins, concanavalin A and Limax flavus agglutinin. Paraffin sections of the Subcommissural Organ and blots of Subcommissural Organ extracts have been analyzed. The ependymal cells of sectioned Subcommissural Organ are strongly stained with the antiserum. Concanavalin A binds to materials in all cytoplasmatic regions, whereas Limax flavus agglutinin identifies materials confined to the apex of the ependymal cells. In the blots, a band of 540 kDa is immunostained. This band is positive for concanavalin A positive but negative for Limax flavus agglutinin and is thereby regarded as representing a precursor form of the secretion.
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Seasonal variation in the secretory activity of the Subcommissural Organ (SCO) of reptiles.
Neuroscience Letters, 1996Co-Authors: Manuel Cifuentes, Juan Pérez, Jesús M. Grondona, Pedro Fernández-llebrezAbstract:Abstract Seasonal variations in the secretory activity of the Subcommissural Organ (SCO) of snakes and turtles was studied by immunocytochemistry, lectins, and electron microscopy. In animals sacrificed in summer, immunoreactive material, mostly devoid of sialic acid, occupied the whole cytoplasm. Cells showed many distended cisternae of rough endoplasmic reticulum and secretory granules. In animals sacrificed in winter, patches of immunoreactive sialic acid-rich material occupied the apical cytoplasm. Cells lacked distended cisternae and the secretory granules formed clusters. These results suggest a decreased synthesis and release of secretory material in the SCO of lethargic reptiles.
M D Lopezavalos - One of the best experts on this subject based on the ideXlab platform.
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rostral floor plate flexural Organ secretes glycoproteins immunologically similar to Subcommissural Organ glycoproteins in dogfish scyliorhinus canicula embryos
Developmental Brain Research, 1997Co-Authors: M D Lopezavalos, Manuel Cifuentes, Juan Pérez, J M Grondona, Elena Miranda, P FernandezllebrezAbstract:Abstract The Subcommissural Organ of vertebrates secretes glycoproteins into the cerebrospinal fluid of the third cerebral ventricle. This material polymerizes in Reissner's fiber. During ontogenetic development, besides the Subcommissural Organ, the ependyma lining the pontine flexure constitutes an additional Reissner's fiber-secreting gland named flexural Organ. We have studied the secretion of the flexural Organ and the Subcommissural Organ in dogfish (Scyliorhinus canicula) embryos using three different antisera and the lectins concanavalin A and wheat germ agglutinin. AFRU is an antiserum against the bovine Reissner's fiber; Ab-600 is an antiserum against 600 kDa dogfish Subcommissural Organ glycoproteins; and APSO is an antiserum against immunoaffinity purified bovine Subcommissural Organ secretory glycoproteins. These three antisera immunostained the flexural Organ indicating that it contains epitopes similar to those present in bovine and dogfish Subcommissural Organ glycoproteins. It seems highly probable that the flexural Organ and the Subcommissural Organ of dogfish embryos secrete similar compound(s). Other ependymal regions were also immunostained with Ab-600 and APSO antisera. Then, Reissner's fiber-like glycoproteins were transiently expressed by most embryonary ependymal cells. These glycoproteins might play a role in the development of the central nervous system of vertebrates.
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secretory glycoproteins of the Subcommissural Organ of the dogfish scyliorhinus canicula evidence for the existence of precursor and processed forms
Cell and Tissue Research, 1995Co-Authors: M D Lopezavalos, Juan Pérez, J M Grondona, J M Perezfigares, Bruno Peruzzo, Esteban M. RodríguezAbstract:The Subcommissural Organ of the dogfish, Scyliorhinus canicula (L), has been investigated by use of antibodies and lectins applied to blots and tissue sections processed for light and electron microscopy. Antibodies have been raised against each of the bands that have previously been identified in immunoblots by the use of antisera raised against secretory glycoproteins extracted from the dogfish Subcommissural Organ, viz., the 600-kDa band and two gel regions including the 475 to 400-kDa and the 145-kDa bands obtained from preparative gels; they are referred to as Ab-600, Ab-475/400, and Ab-145. These antisera and the lectins concanavalin A and wheat germ agglutinin have been used for the staining of: (1) blots of extracts of the dogfish Subcommissural Organ and optic tectum; (2) tissue sections of the dogfish brain. The findings indicate that the bands of 600, 475 and 400 kDa contain compounds that should be regarded as secretory glycoproteins of the dogfish Subcommissural Organ. The 600-kDa and 400-kDa bands are labeled by concanavalin A; wheat germ agglutinin labels the 475-kDa band strongly and the other two weakly. Ab-600 reacts with the bands at 600, 475 and 400 kDa and stains materials stored in the rough endoplasmic reticulum and secretory granules of 200–600 nm in diameter. The 600-kDa compound is probably a precursor form. Ab-475/400 stains the same three bands revealed by Ab-600; immunocytochemically, it reacts with two types of secretory granules (200–600 and 800–1200 nm in diameter) but it does not label the rough endoplasmic reticulum. Ab-145 reveals the bands at 600, 475 and 400 kDa and a diffuse zone in the region of 145 kDa; in light-microscopic immunocytochemistry, it behaves as Ab-475/400. The 475-kDa and 400-kDa glycoproteins, and a compound of approximately 145 kDa thus probably correspond to processed forms. Ab-475/400 stains granules present in cell processes ending on local blood vessels and at the leptomeninges. Since this antiserum selectively labels secretory granules, this finding may be taken as evidence for a basal route of secretion.
