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1.
Mol Psychiatry ; 23(5): 1278-1286, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-28727686

RESUMEN

Disrupted in schizophrenia 1 (DISC1) is a multi-functional scaffolding protein that has been associated with neuropsychiatric disease. The role of DISC1 is to assemble protein complexes that promote neural development and signaling, hence tight control of the concentration of cellular DISC1 in neurons is vital to brain function. Using structural and biochemical techniques, we show for we believe the first time that not only is DISC1 turnover elicited by the ubiquitin proteasome system (UPS) but that it is orchestrated by the F-Box protein, FBXW7. We present the structure of FBXW7 bound to the DISC1 phosphodegron motif and exploit this information to prove that disruption of the FBXW7-DISC1 complex results in a stabilization of DISC1. This action can counteract DISC1 deficiencies observed in neural progenitor cells derived from induced pluripotent stem cells from schizophrenia patients with a DISC1 frameshift mutation. Thus manipulation of DISC1 levels via the UPS may provide a novel method to explore DISC1 function.


Asunto(s)
Proteína 7 que Contiene Repeticiones F-Box-WD/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Ubiquitina/metabolismo , Células Cultivadas , Proteína 7 que Contiene Repeticiones F-Box-WD/genética , Células HEK293 , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Modelos Moleculares , Proteínas del Tejido Nervioso/genética , Células-Madre Neurales/metabolismo , Neurogénesis , Neuronas/metabolismo , Complejo de la Endopetidasa Proteasomal/genética , Unión Proteica , Esquizofrenia/metabolismo , Transducción de Señal , Ubiquitina/genética , Ubiquitinación
2.
Mol Psychiatry ; 19(1): 88-98, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23164821

RESUMEN

Although the mechanism of Aß action in the pathogenesis of Alzheimer's disease (AD) has remained elusive, it is known to increase the expression of the antagonist of canonical wnt signalling, Dickkopf-1 (Dkk1), whereas the silencing of Dkk1 blocks Aß neurotoxicity. We asked if clusterin, known to be regulated by wnt, is part of an Aß/Dkk1 neurotoxic pathway. Knockdown of clusterin in primary neurons reduced Aß toxicity and DKK1 upregulation and, conversely, Aß increased intracellular clusterin and decreased clusterin protein secretion, resulting in the p53-dependent induction of DKK1. To further elucidate how the clusterin-dependent induction of Dkk1 by Aß mediates neurotoxicity, we measured the effects of Aß and Dkk1 protein on whole-genome expression in primary neurons, finding a common pathway suggestive of activation of wnt-planar cell polarity (PCP)-c-Jun N-terminal kinase (JNK) signalling leading to the induction of genes including EGR1 (early growth response-1), NAB2 (Ngfi-A-binding protein-2) and KLF10 (Krüppel-like factor-10) that, when individually silenced, protected against Aß neurotoxicity and/or tau phosphorylation. Neuronal overexpression of Dkk1 in transgenic mice mimicked this Aß-induced pathway and resulted in age-dependent increases in tau phosphorylation in hippocampus and cognitive impairment. Furthermore, we show that this Dkk1/wnt-PCP-JNK pathway is active in an Aß-based mouse model of AD and in AD brain, but not in a tau-based mouse model or in frontotemporal dementia brain. Thus, we have identified a pathway whereby Aß induces a clusterin/p53/Dkk1/wnt-PCP-JNK pathway, which drives the upregulation of several genes that mediate the development of AD-like neuropathologies, thereby providing new mechanistic insights into the action of Aß in neurodegenerative diseases.


Asunto(s)
Péptidos beta-Amiloides/toxicidad , Clusterina/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Neuronas/efectos de los fármacos , Proteínas Wnt/metabolismo , Anciano , Enfermedad de Alzheimer/patología , Animales , Células Cultivadas , Clusterina/genética , Embrión de Mamíferos , Inhibidores Enzimáticos/farmacología , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Péptidos y Proteínas de Señalización Intercelular/genética , Sistema de Señalización de MAP Quinasas/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratas , Ratas Sprague-Dawley
3.
Sci Total Environ ; 731: 138851, 2020 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-32408204

RESUMEN

Provision of supplementary food for garden birds is practiced on a large scale in multiple countries. While this resource has benefits for wild bird populations, concern has been expressed regarding the potential for contamination of foodstuffs by mycotoxins, and the implications this might have for wildlife health. We investigated whether aflatoxin (AF) and ochratoxin A (OA) residues are present in foodstuffs sold for wild bird consumption at point of sale in Great Britain using high pressure liquid chromatography analyses. The hypothesis that production of these mycotoxins occurs in British climatic conditions, or under storage conditions after the point of sale, was tested under experimental conditions but was not proved by our study. While the majority of peanut samples were negative for AF residues, 10% (10/98) of samples at point of sale and 11% (13/119) of those across the storage and climate exposure treatment replicates contained AFB1 that exceeded the maximum permitted limit of 20 µg/kg. No significant difference was found in the detection of either mycotoxin between branded and non-branded products. The clinical significance, if any, of exposure of wild birds to mycotoxins requires further investigation. Nevertheless, the precautionary principle should be adopted and best practice steps to reduce the likelihood of wild bird exposure to mycotoxins are recommended.


Asunto(s)
Aflatoxinas/análisis , Micotoxinas/análisis , Animales , Aves , Contaminación de Alimentos/análisis , Ocratoxinas , Reino Unido
4.
J Cell Biol ; 129(2): 535-47, 1995 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-7721949

RESUMEN

The tectorial membrane is an extracellular matrix lying over the apical surface of the auditory epithelium. Immunofluorescence studies have suggested that some proteins of the avian tectorial membrane, the tectorins, may be unique to the inner ear (Killick, R., C. Malenczak, and G. P. Richardson. 1992. Hearing Res. 64:21-38). The cDNA and deduced amino acid sequences for chick beta-tectorin are presented. The cDNA encodes a protein of 36,902.6 D with a putative signal sequence, four potential N-glycosylation sites, 13 cysteines, and a hydrophobic COOH terminus. Western blots of two-dimensional gels using antibodies to a synthetic peptide confirm the identity of the cDNA. Southern and Northern analysis suggests that beta-tectorin is a single-copy gene only expressed in the inner ear. The predicted COOH terminus is similar to that of glycosylphosphatidylinositol-linked proteins, and antisera raised to this region react with in vitro translation products of the cDNA clone but not with mature beta-tectorin. These data suggest beta-tectorin is synthesized as a glycosylphosphatidyl-inositol-linked precursor, targeted to the apical surface of the sensory epithelium by the lipid moiety, and then further processed. Sequence analysis indicates the predicted protein possesses a zona pellucida domain, a sequence that is common to a limited number of other matrix-forming proteins and may be involved in the formation of filaments. In the cochlear duct, beta-tectorin is expressed in the basilar papilla, in the clear cells and the cuboidal cells, as well as in the striolar region of the lagena macula. The expression of beta-tectorin is associated with hair cells that have an apical cell surface specialization known as the 275-kD hair cell antigen restricted to the basal region of the hair bundle, suggesting that matrices containing beta-tectorin are required to drive this hair cell type.


Asunto(s)
Conducto Coclear/química , Proteínas de la Matriz Extracelular/genética , Proteínas de la Membrana/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Pollos , Clonación Molecular , ADN/análisis , ADN Complementario/genética , Proteínas de la Matriz Extracelular/química , Proteínas de la Matriz Extracelular/inmunología , Proteínas de la Matriz Extracelular/aislamiento & purificación , Proteínas Ligadas a GPI , Expresión Génica , Glicosilación , Proteínas de la Membrana/química , Proteínas de la Membrana/inmunología , Proteínas de la Membrana/aislamiento & purificación , Datos de Secuencia Molecular , Peso Molecular , Oligopéptidos/síntesis química , Oligopéptidos/inmunología , Especificidad de Órganos , ARN Mensajero/análisis , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido
5.
Sci Rep ; 9(1): 20204, 2019 12 27.
Artículo en Inglés | MEDLINE | ID: mdl-31882919

RESUMEN

This work investigated in Alzheimer's disease dementia (AD), whether the probability of making an error on a task (or a correct response) was influenced by the outcome of the previous trials. We used the antisaccade task (AST) as a model task given the emerging consensus that it provides a promising sensitive and early biological test of cognitive impairment in AD. It can be employed equally well in healthy young and old adults, and in clinical populations. This study examined eye-movements in a sample of 202 participants (42 with dementia due to AD; 65 with mild cognitive impairment (MCI); 95 control participants). The findings revealed an overall increase in the frequency of AST errors in AD and MCI compared to the control group, as predicted. The errors on the current trial increased in proportion to the number of consecutive errors on the previous trials. Interestingly, the probability of errors was reduced on the trials that followed a previously corrected error, compared to the trials where the error remained uncorrected, revealing a level of adaptive control in participants with MCI or AD dementia. There was an earlier peak in the AST distribution of the saccadic reaction times for the inhibitory errors in comparison to the correct saccades. These findings revealed that the inhibitory errors of the past have a negative effect on the future performance of healthy adults as well as people with a neurodegenerative cognitive impairment.


Asunto(s)
Enfermedad de Alzheimer/patología , Disfunción Cognitiva/patología , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Tiempo de Reacción/fisiología , Movimientos Sacádicos
6.
Sci Rep ; 9(1): 10396, 2019 07 17.
Artículo en Inglés | MEDLINE | ID: mdl-31316114

RESUMEN

Measuring vision in rodents is a critical step for understanding vision, improving models of human disease, and developing therapies. Established behavioural tests for perceptual vision, such as the visual water task, rely on learning. The learning process, while effective for sighted animals, can be laborious and stressful in animals with impaired vision, requiring long periods of training. Current tests that that do not require training are based on sub-conscious, reflex responses (e.g. optokinetic nystagmus) that don't require involvement of visual cortex and higher order thalamic nuclei. A potential alternative for measuring vision relies on using visually guided innate defensive responses, such as escape or freeze, that involve cortical and thalamic circuits. In this study we address this possibility in mice with intact and degenerate retinas. We first develop automatic methods to detect behavioural responses based on high dimensional tracking and changepoint detection of behavioural time series. Using those methods, we show that visually guided innate responses can be elicited using parametisable stimuli, and applied to describing the limits of visual acuity in healthy animals and discriminating degrees of visual dysfunction in mouse models of retinal degeneration.


Asunto(s)
Estimulación Luminosa/métodos , Retina/fisiopatología , Percepción Visual/fisiología , Animales , Electrorretinografía/métodos , Femenino , Instinto , Masculino , Ratones , Ratones Endogámicos C57BL , Movimiento/fisiología , Degeneración Retiniana/fisiopatología , Visión Ocular/fisiología , Agudeza Visual/fisiología , Corteza Visual/fisiopatología
7.
J Comp Pathol ; 156(4): 451-457, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28391972

RESUMEN

Five juvenile pied imperial pigeons (Ducula bicolor) presented with neurological signs including torticollis, ataxia and poor flying ability. All were humanely destroyed and submitted for post-mortem examination. Microscopically, the most significant findings were in the brain and spinal cord. Spheroid formation was evident within the medulla, pons, diencephalon, cortical grey and subcortical white matter, spinal cord white and grey matter and the granular and molecular cell layers of the cerebellum. There was no evidence of associated inflammation. Immunohistochemistry revealed positive labelling within the spheroids for S100 axons and phosphorylated neurofilaments including SMI31, neurofilament cocktail and microtubule-associated protein 2. Transmission electron microscopy confirmed the light microscopical findings of frequent axonal spheroids. These results are consistent with neuroaxonal dystrophy, which has not been described previously in pigeons. This highlights the importance of considering neuroaxonal dystrophy in juvenile birds with neurological signs. A genetic basis is suspected in this group.


Asunto(s)
Enfermedades de las Aves/patología , Columbidae , Distrofias Neuroaxonales/veterinaria , Animales , Femenino , Masculino
8.
Transl Psychiatry ; 7(6): e1148, 2017 06 06.
Artículo en Inglés | MEDLINE | ID: mdl-28585932

RESUMEN

The repressor element 1-silencing transcription (REST) factor is a key regulator of the aging brain's stress response. It is reduced in conditions of stress and Alzheimer's disease (AD), which suggests that increasing REST may be neuroprotective. REST can be measured peripherally in blood plasma. Our study aimed to (1) examine plasma REST levels in relation to clinical and biological markers of neurodegeneration and (2) alter plasma REST levels through a stress-reduction intervention-mindfulness training. In study 1, REST levels were compared across the following four well-characterized groups: healthy elderly (n=65), mild cognitive impairment who remained stable (stable MCI, n=36), MCI who later converted to dementia (converter MCI, n=29) and AD (n=65) from the AddNeuroMed cohort. REST levels declined with increasing severity of risk and impairment (healthy elderly>stable MCI>converter MCI>AD, F=6.35, P<0.001). REST levels were also positively associated with magnetic resonance imaging-based hippocampal and entorhinal atrophy and other putative blood-based biomarkers of AD (Ps<0.05). In study 2, REST was measured in 81 older adults with psychiatric risk factors for AD before and after a mindfulness-based stress reduction intervention or an education-based placebo intervention. Mindfulness-based training caused an increase in REST compared with the placebo intervention (F=8.57, P=0.006), and increased REST was associated with a reduction in psychiatric symptoms associated with stress and AD risk (Ps<0.02). Our data confirm plasma REST associations with clinical severity and neurodegeneration, and originally, that REST is modifiable by a psychological intervention with clinical benefit.


Asunto(s)
Enfermedad de Alzheimer/diagnóstico , Atención Plena , Proteínas Represoras/sangre , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/sangre , Enfermedad de Alzheimer/diagnóstico por imagen , Biomarcadores/sangre , Encéfalo/diagnóstico por imagen , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Pruebas Neuropsicológicas , Educación del Paciente como Asunto
9.
J Neurosci ; 21(14): 4987-95, 2001 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-11438574

RESUMEN

Alzheimer's disease (AD) is a disorder of two pathologies: amyloid plaques, the core of which is a peptide derived from the amyloid precursor protein (APP), and neurofibrillary tangles composed of highly phosphorylated tau. Protein kinase C (PKC) is known to increase non-amyloidogenic alpha-secretase cleavage of APP, producing secreted APP (sAPPalpha), and glycogen synthase kinase (GSK)-3beta is known to increase tau phosphorylation. Both PKC and GSK-3beta are components of the wnt signaling cascade. Here we demonstrate that overexpression of another member of this pathway, dishevelled (dvl-1), increases sAPPalpha production. The dishevelled action on APP is mediated via both c-jun terminal kinase (JNK) and protein kinase C (PKC)/mitogen-activated protein (MAP) kinase but not via p38 MAP kinase. These data position dvl-1 upstream of both PKC and JNK, thereby explaining the previously observed dual signaling action of dvl-1. Furthermore, we show that human dvl-1 and wnt-1 also reduce the phosphorylation of tau by GSK-3beta. Therefore, both APP metabolism and tau phosphorylation are potentially linked through wnt signaling.


Asunto(s)
Precursor de Proteína beta-Amiloide/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Fosfoproteínas/metabolismo , Proteína Quinasa C/metabolismo , Proteínas de Pez Cebra , Proteínas Adaptadoras Transductoras de Señales , Enfermedad de Alzheimer/metabolismo , Secretasas de la Proteína Precursora del Amiloide , Precursor de Proteína beta-Amiloide/genética , Ácido Aspártico Endopeptidasas , Proteínas Quinasas Dependientes de Calcio-Calmodulina/genética , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Línea Celular , Proteínas Dishevelled , Endopeptidasas/metabolismo , Expresión Génica , Glucógeno Sintasa Quinasa 3 , Glucógeno Sintasa Quinasas , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos , Riñón/citología , Riñón/efectos de los fármacos , Riñón/metabolismo , Mutación , Fosfoproteínas/genética , Fosfoproteínas/farmacología , Fosforilación/efectos de los fármacos , Proteínas/genética , Proteínas/metabolismo , Proteínas/farmacología , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas/farmacología , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Recombinantes de Fusión/farmacología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología , Transfección , Proteínas Wnt , Proteína Wnt1 , Proteínas tau/genética , Proteínas tau/metabolismo
10.
Biochim Biophys Acta ; 1350(1): 33-7, 1997 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-9003454

RESUMEN

Three splice variants of the alpha subunit of the amiloride-sensitive epithelial sodium channel (alpha ENaC) have been isolated from a chicken cochlear cDNA library. A PCR product, generated from the cochlear library using degenerate primers to regions of homology between the rat alpha ENaC and the degenerin Mec-4, was used as a probe. The three splice variant cDNAs with sizes of 2321, 3399 and 3845 bp correspond to transcripts of 2.5, 3.5 and 3.9 kb as detected by Northern blot analysis. The 3399 bp clone differs from the 2321 clone solely by the addition of 1079 bases in the 3'-non-coding region. Both these cDNAs code for an identical predicted protein of 637 amino acids which has 68% similarity to the rat alpha ENaC, and is probably the chicken homologue of alpha ENaC. The third cDNA of 3845 bp is similar to the 3399 bp clone but includes two exons within the open reading frame. The first of these exons introduces a premature stop codon resulting in a truncated predicted protein of 434 amino acids. Northern blot analysis shows expression of the 2.5 and 3.5 kb transcripts in cochlea and colon, the 2.5 kb transcript in cartilage, whilst the 3.9 kb transcript is only detected in cochlea. No expression is detected in brain, liver, and heart nor, most notably, in lung or kidney.


Asunto(s)
Empalme Alternativo , Cóclea/metabolismo , Variación Genética , Canales de Sodio/biosíntesis , Canales de Sodio/genética , Amilorida , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Pollos , Cartilla de ADN , ADN Complementario , Epitelio/metabolismo , Biblioteca de Genes , Sustancias Macromoleculares , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Reacción en Cadena de la Polimerasa , Ratas , Homología de Secuencia de Aminoácido , Canales de Sodio/química , Transcripción Genética , Xenopus
11.
Transl Psychiatry ; 5: e584, 2015 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-26080319

RESUMEN

There is great interest in blood-based markers of Alzheimer's disease (AD), especially in its pre-symptomatic stages. Therefore, we aimed to identify plasma proteins whose levels associate with potential markers of pre-symptomatic AD. We also aimed to characterise confounding by genetics and the effect of genetics on blood proteins in general. Panel-based proteomics was performed using SOMAscan on plasma samples from TwinsUK subjects who are asymptomatic for AD, measuring the level of 1129 proteins. Protein levels were compared with 10-year change in CANTAB-paired associates learning (PAL; n = 195), and regional brain volumes (n = 34). Replication of proteins associated with regional brain volumes was performed in 254 individuals from the AddNeuroMed cohort. Across all the proteins measured, genetic factors were found to explain ~26% of the variability in blood protein levels on average. The plasma level of the mitogen-activated protein kinase (MAPK) MAPKAPK5 protein was found to positively associate with the 10-year change in CANTAB-PAL in both the individual and twin difference context. The plasma level of protein MAP2K4 was found to suggestively associate negatively (Q < 0.1) with the volume of the left entorhinal cortex. Future studies will be needed to assess the specificity of MAPKAPK5 and MAP2K4 to eventual conversion to AD.


Asunto(s)
Enfermedad de Alzheimer/sangre , Encéfalo/patología , Endofenotipos , Péptidos y Proteínas de Señalización Intracelular/sangre , MAP Quinasa Quinasa 4/sangre , Proteínas Serina-Treonina Quinasas/sangre , Gemelos/genética , Anciano , Enfermedad de Alzheimer/patología , Enfermedades Asintomáticas , Biomarcadores/sangre , Corteza Entorrinal/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Tamaño de los Órganos , Gemelos/psicología
12.
Neurosci Lett ; 354(1): 54-8, 2004 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-14698481

RESUMEN

Expansion of the polyglutamine repeat region of the androgen receptor (AR) results in Kennedy's disease, a neurological disorder typified by degeneration of motor neurons in the brain stem and spinal cord. As the AR has been shown to inhibit beta-catenin dependent (Wnt) signalling we asked if expansion of the polyglutamine repeats might affect this property of the protein. Using the TOPflash/FOPflash reporter assay we found that a pathogenic form of the AR containing 51 glutamine repeats showed a consistent, though minimal, reduction in its ability to inhibit beta-catenin-mediated transcription, in comparison to a non-pathogenic form with 20 repeats. A reduced ability to inhibit Wnt signalling may thus contribute in part to the underlying aetiology of Kennedy's disease.


Asunto(s)
Proteínas del Citoesqueleto/metabolismo , Expansión de las Repeticiones de ADN , Proteínas de Unión al ADN/metabolismo , Atrofia Muscular Espinal/genética , Receptores Androgénicos/genética , Receptores Androgénicos/metabolismo , Transactivadores/metabolismo , Factores de Transcripción/metabolismo , Proteínas de Pez Cebra , Línea Celular , Genes Reporteros , Humanos , Riñón/citología , Factor de Unión 1 al Potenciador Linfoide , Atrofia Muscular Espinal/fisiopatología , Degeneración Nerviosa/genética , Degeneración Nerviosa/fisiopatología , Péptidos/genética , Proteínas Proto-Oncogénicas/metabolismo , Transducción de Señal/fisiología , Transcripción Genética/fisiología , Proteínas Wnt , beta Catenina
13.
Hear Res ; 103(1-2): 131-41, 1997 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9007580

RESUMEN

Polyclonal antibodies were raised in chickens to the glycosylated forms of the high (H), medium (M) and low (L) molecular mass (MM) mouse tectorins. In the mouse cochlea, all three antibodies stained the tectorial membrane. Antibodies raised to HMM tectorin also stained the hair bundles of both inner and outer hair cells. A number of other mouse tissues were screened with the anti-tectorin antibodies to look for similar or antigenically related molecules. Staining was not observed in any other tissue type with the antibodies directed against the MMM and LMM tectorins. In the nose, the anti-HMM tectorin antibodies stained Bowman's glands and the mucus layer overlying the olfactory epithelium. The surface of the adjacent respiratory epithelium was not stained by these antibodies. HMM tectorin can be specifically radiolabelled by injecting neonatal mice with 35SO4 and undergoes a shift in electrophoretic mobility following treatment with keratanase, an endo-beta-galactosidase from Pseudomonas. However, when centrifuged on shallow CsCl gradients HMM tectorin has a buoyant density similar to that of glycoproteins and does not behave as a typical cartilage type proteoglycan. HMM tectorin does not react with mab 5D4, a monoclonal antibody that recognises keratan sulphate glycosaminoglycan from corneal and skeletal muscle proteoglycan. Unlike antibodies to HMM tectorin, mab 5D4 selectively stains the upper surface of the tectorial membrane, Hensen's stripe and the mucus layer overlying the respiratory epithelium. These studies indicate that the MMM and LMM tectorins may be unique to the cochlea, and that HMM may be a "light' keratan sulphate proteoglycan that is antigenically related to either the mucins or a more specific component of the olfactory mucus layer.


Asunto(s)
Proteínas de la Matriz Extracelular/metabolismo , Células Ciliadas Auditivas/metabolismo , Proteínas de la Membrana/metabolismo , Mucosa Olfatoria/metabolismo , Membrana Tectoria/metabolismo , Animales , Anticuerpos , Anticuerpos Monoclonales , Proteoglicanos Tipo Condroitín Sulfato/metabolismo , Proteínas de la Matriz Extracelular/química , Proteínas de la Matriz Extracelular/inmunología , Proteínas Ligadas a GPI , Sulfato de Queratano/metabolismo , Lumican , Proteínas de la Membrana/química , Proteínas de la Membrana/inmunología , Ratones , Microscopía Fluorescente , Peso Molecular , Coloración y Etiquetado , Sulfatos/metabolismo , Membrana Tectoria/anatomía & histología
14.
Hear Res ; 64(1): 21-38, 1992 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1490898

RESUMEN

Gel electrophoretic analysis of the avian tectorial membrane under non-reducing conditions reveals the presence of 2 major proteins with apparent molecular masses of 195 and 41 kDa on 8.25% gels. Under reducing conditions, 6 polypeptides with apparent molecular masses of 146, 60, 56, 43, 35 and 31 kDa are consistently observed. None of these six polypeptides observed under reducing conditions are sensitive to digestion with collagenase, and all, except for the 43 kDa component, are degraded by treatment with cold acidic pepsin. The 60, 56 and 43 kDa polypeptides bind the peroxidase conjugated lectins from Canavalia ensiformis and Triticum vulgaris, indicating the presence of mannose, N-acetyl glucosamine and/or sialic acid. The 146, 60 and 56 kDa bands undergo a shift in electrophoretic mobility after treatment of native tectorial membranes with the enzyme neuroaminidase. Fibronectin and Type II collagen cannot be detected in the avian tectorial membrane by either immunoblotting or immunofluorescence techniques. Polyclonal antisera raised against the different polypeptides after partial purification by one dimensional gel electrophoresis confirm that these proteins are all components of the tectorial membrane, and show that they are restricted to the otolithic and tectorial membranes within the inner ear. Analysis of a wide variety of other tissue types indicates that the 60, 43 and 35 kDa components can only be detected within the inner ear, and that the antisera recognising the 146 and 31 kDa components only show cross-reactivity within the head, with the anti-146 kDa antibodies staining the mucus ducts supplying the olfactory epithelium and the anti-31 kDa antibodies staining granular elements in the cells of the respiratory epithelium. The results suggest that certain of the tectorial membrane components may be novel matrix molecules unique to the inner ear, and that some of the other proteins may be antigenically related to mucins.


Asunto(s)
Pollos/metabolismo , Proteínas/química , Membrana Tectoria/química , Animales , Colagenasas/metabolismo , Electroforesis en Gel Bidimensional , Electroforesis en Gel de Poliacrilamida , Immunoblotting , Focalización Isoeléctrica , Lectinas , Microscopía Fluorescente , Peso Molecular , Pepsina A/metabolismo , Péptidos/análisis , Péptidos/química , Proteínas/análisis
15.
Hear Res ; 96(1-2): 167-78, 1996 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-8817316

RESUMEN

Expression of beta-tectorin mRNA in the inner ear of the embryonic and early posthatch (PH) chick was studied by in situ hybridisation. In the PH chick, beta-tectorin mRNA is expressed in the basilar papilla, in the clear and the cuboidal cells that lie either side of the papilla, in the striolar regions of the maculae, and in two small groups of cells lying adjacent to the midline in the cristae of the anterior and posterior ampullae. Expression of beta-tectorin is not observed in the lateral ampulla. In the sensory epithelia of the PH chick in which beta-tectorin mRNA is detected, expression is restricted to the supporting cell population. During development of the cochlear duct, beta-tectorin expression begins between embryonic (E) days 5 and 6. At E6, expression is observed throughout the length of the duct but is highest at the distal end. By E7, the pattern of expression is reversed and is highest at the proximal end of the cochlea, suggesting that a wave of high beta-tectorin expression passes disto-proximally along the papilla during E6 and E7. Expression of beta-tectorin mRNA is not detected in the homogene cells at any stage during the development of the cochlear duct, indicating that these cells do not synthesise one of the two major proteins of the avian tectorial membrane. The distribution of supporting cells expressing beta-tectorin mRNA in the different epithelia was compared with the distribution of sensory cells that have type B hair bundles, those with shaft links restricted to basal regions of their stereocilia, and sensory cells that have type A bundles, those with shaft links all over the entire surface of their stereocilia. Hair cells with type A hair bundles are never found in association with supporting cells expressing beta-tectorin. Although there is a correspondence in the basilar papilla and the maculae of the utriculus and lagena between the distribution of supporting cells expressing beta-tectorin mRNA and hair cells with type B bundles, this correlation does not generalise to the other sensory epithelia.


Asunto(s)
Proteínas de la Matriz Extracelular/metabolismo , Proteínas de la Membrana/metabolismo , ARN Mensajero/metabolismo , Membrana Tectoria/metabolismo , Animales , Embrión de Pollo , Pollos , Clonación Molecular , Cóclea/citología , Cóclea/fisiología , ADN Complementario/química , ADN Complementario/genética , Proteínas de la Matriz Extracelular/genética , Proteínas Ligadas a GPI , Regulación del Desarrollo de la Expresión Génica/genética , Células Ciliadas Auditivas/citología , Células Ciliadas Auditivas/fisiología , Hibridación in Situ , Proteínas de la Membrana/genética , ARN Mensajero/genética , Coloración y Etiquetado
16.
Hear Res ; 157(1-2): 100-11, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11470190

RESUMEN

Immunohistochemical data indicate that OCP1 co-localizes exactly with OCP2 in the epithelial gap junction region of the guinea pig organ of Corti (OC). Despite the abundance of OCP1 in the OC, gaining access to its coding sequence -- and, in particular, the 5' end of the coding sequence -- proved unexpectedly challenging. The putative full-length OCP1 cDNA -- 1180 nucleotides in length -- includes a 67 nucleotide 5' leader sequence, 300 codons (including initiation and termination signals), and a 216 nucleotide 3' untranslated region. The cDNA encodes a protein having a predicted molecular weight of 33,700. The inferred amino acid sequence harbors an F-box motif spanning residues 52--91, consistent with a role for OCP1 and OCP2 in the proteasome-mediated degradation of select OC proteins. Although OCP1 displays extensive homology to an F-box protein recently cloned from rat brain (NFB42), clustered sequence non-identities indicate that the two proteins are transcribed from distinct genes. The presumptive human OCP1 gene was identified in the human genome databank. Located on chromosome 1p35, the inferred translation product exhibits 94% identity with the guinea pig OCP1 coding sequence.


Asunto(s)
Cóclea/metabolismo , Factores de Transcripción/metabolismo , Secuencia de Aminoácidos , Animales , Anticuerpos Monoclonales , Especificidad de Anticuerpos , Secuencia de Bases , Proteínas de Ciclo Celular/genética , Clonación Molecular , Cartilla de ADN/genética , ADN Complementario/genética , Epitelio/metabolismo , Proteínas F-Box , Uniones Comunicantes/metabolismo , Cobayas , Inmunohistoquímica , Ratones , Datos de Secuencia Molecular , Proteínas del Tejido Nervioso/genética , Órgano Espiral/metabolismo , Reacción en Cadena de la Polimerasa , Ratas , Proteínas Quinasas Asociadas a Fase-S , Homología de Secuencia de Aminoácido , Factores de Transcripción/genética
17.
Rev Sci Instrum ; 85(9): 095114, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25273779

RESUMEN

We describe a system to transport and identify barium ions produced in liquid xenon, as part of R&D towards the second phase of a double beta decay experiment, nEXO. The goal is to identify the Ba ion resulting from an extremely rare nuclear decay of the isotope (136)Xe, hence providing a confirmation of the occurrence of the decay. This is achieved through Resonance Ionization Spectroscopy (RIS). In the test setup described here, Ba ions can be produced in liquid xenon or vacuum and collected on a clean substrate. This substrate is then removed to an analysis chamber under vacuum, where laser-induced thermal desorption and RIS are used with time-of-flight mass spectroscopy for positive identification of the barium decay product.

18.
Neurosci Lett ; 533: 96-9, 2013 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-23153828

RESUMEN

Large-scale genome-wide SNP association studies have identified an association between variants of CR1, the gene encoding complement component receptor 1, and the sporadic form of Alzheimer's disease. The role of CR1 and the complement system in Alzheimer's disease remains far from clear. In rodents the closest ortholog of CR1 is the Crry gene (Cr1-related protein Y). To begin to explore its role in Alzheimer's disease we examined hippocampal lysates from Crry(-/-) mice and age matched controls by immunoblotting. We measured complement factor H, a component of the complement system and biomarker for Alzheimer's disease progression, and tau phosphorylation at the serine 235 site, hyperphosphorylated forms of tau being a defining neuropathological hallmark of the disease. We found that levels of CFH and of tau phosphorylation at serine 235 were strongly and significantly reduced in Crry(-/-) samples. These observations provide a starting point for further attempts to determine the role of CR1 in the neuropathological process driving Alzheimer's disease.


Asunto(s)
Enfermedad de Alzheimer/genética , Factor H de Complemento/metabolismo , Hipocampo/metabolismo , Receptores de Complemento 3b/genética , Receptores de Complemento/genética , Proteínas tau/metabolismo , Animales , Humanos , Ratones , Ratones Noqueados , Fosforilación
19.
J Comp Pathol ; 149(1): 119-25, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23218410

RESUMEN

Otarine herpesvirus (OtHV)-1-associated urogenital carcinoma has been well documented in the California sea lion (Zalophus californianus, CSL), but this is the first report of this tumour in a captive South American fur seal (Arctocephalus australis, SAFS). The gross and microscopical morphology of the tumour in the SAFS was identical to that described previously in CSLs and the tumour in the present case had metastasized within the urogenital tract and draining lymph nodes and to the lungs and one kidney. Immunohistochemistry revealed intra- and extracytoplasmic labelling of herpesvirus antigen in the cells of the tumour tissue and transitional epithelium of the urethra. OtHV-1 nucleic acids were detected within tumour tissue and from a urogenital swab by polymerase chain reaction. The ranges of these two species of pinniped do not overlap normally in the wild, suggesting that transmission of OtHV-1 probably occurred in captivity. This confirmed susceptibility of the SAFS to the development of OtHV-1-associated urogenital carcinoma suggests that all species of Otariidae should be screened for OtHV-1 infection prior to movement within and between zoological collections.


Asunto(s)
Lobos Marinos , Infecciones por Herpesviridae/veterinaria , Neoplasias Urogenitales/veterinaria , Animales , Femenino , Infecciones por Herpesviridae/virología , América del Sur , Neoplasias Urogenitales/virología
20.
Vet Parasitol ; 190(1-2): 95-103, 2012 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-22763348

RESUMEN

Taeniid tapeworms which include Echinococcus and Taenia spp. are obligatory parasites of mammals with pathogenicity usually related to the larval stages of the life cycle. Two species (or genotypes) of Echinococcus, E. granulosus sensu stricto and E. equinus, as well as several Taenia spp. are endemic in the UK. Here we report on the occurrence of larval cystic stages of Echinococcus and Taenia spp. in captive mammals in the UK. Using molecular techniques we have identified E. granulosus (G1 genotype) in a guenon monkey and a Philippine spotted deer; E. equinus in a zebra and a lemur; E. ortleppi in a Philippine spotted deer; E. multilocularis in a macaque monkey and Taenia polyacantha in jumping rats. To the best of our knowledge this is the first report of E. multilocularis in a captive primate translocated to the UK. As far as we know these are the first reports of E. equinus in a primate (lemur) and in a zebra; as well as E. granulosus (G1 genotype) and E. ortleppi in a cervid translocated to the UK. These infections and implications of the potential establishment of exotic species of cestodes are discussed.


Asunto(s)
Animales de Zoológico/parasitología , Equinococosis/veterinaria , Echinococcus/aislamiento & purificación , Mamíferos/parasitología , Taenia/aislamiento & purificación , Teniasis/veterinaria , Animales , Secuencia de Bases , Cercopithecus/parasitología , ADN de Helmintos/genética , Ciervos/parasitología , Equinococosis/epidemiología , Equinococosis/parasitología , Equinococosis/patología , Echinococcus/genética , Equidae/parasitología , Femenino , Genotipo , Lemuridae/parasitología , Hígado/parasitología , Hígado/patología , Pulmón/parasitología , Pulmón/patología , Macaca/parasitología , Masculino , Datos de Secuencia Molecular , Enfermedades de los Primates/epidemiología , Enfermedades de los Primates/parasitología , Enfermedades de los Primates/patología , Roedores , Análisis de Secuencia de ADN , Taenia/genética , Teniasis/epidemiología , Teniasis/parasitología , Teniasis/patología , Reino Unido/epidemiología
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