RESUMEN
The work aims to analyze the associations of polymorphic variants of the PRL and BLG genes with resistance and susceptibility to mastitis in Holstein cows. The experimental study consisted of the selection of biomaterial samples from 250 heads of Holstein cows aged 3 years divided into two groups (healthy and with a confirmed diagnosis of mastitis). The determination of animal genotypes was carried out using polymerase chain reaction and restriction fragment length polymorphism. The study of the nature of the association of polymorphic variants of the PRL and BLG gene with resistance/increased risk of mastitis established a significant deviation from the theoretically expected distribution of bBLG-HaeIII genotypes in the group of animals suffering from mastitis (the value of χ2 was 0.24). The bBLG-HaeIIIBB genotype can act as a marker of an increased risk of developing mastitis in Holstein cows; its frequency in the group of sick animals exceeds the frequency in the control group by more than 2 times (44.0 compared to 17.0%, respectively). The bBLG-HaeIIIAB genotype is significantly associated with mastitis resistance in Holstein cows; its frequency is 2 times lower than in the control group (28.0 compared to 54.0%).
Asunto(s)
Predisposición Genética a la Enfermedad , Genotipo , Lactoglobulinas , Mastitis Bovina , Reacción en Cadena de la Polimerasa , Polimorfismo Genético , Prolactina , Animales , Bovinos , Femenino , Mastitis Bovina/genética , Prolactina/genética , Reacción en Cadena de la Polimerasa/veterinaria , Lactoglobulinas/genética , Polimorfismo de Longitud del Fragmento de Restricción , Frecuencia de los GenesRESUMEN
The process of forming three-component nanocrystalline fibers and powders of zirconia, yttria and alumina is studied depending on the component ratio and heat treatment temperature. It has been found that in the investigated system at 500-600 degrees C a nanocrystalline triple solid solution is formed, which exists up to 1200 degrees C. Beyond the above temperature, the triple solid solution decomposes into individual components. Specific regularities of changes in the crystalline structure and size of nanograins of oxides of triple solid solutions in the ZrO2(Y2O3)-Al2O3 system are established depending on the composition and thermal action. The structure--crystallite size--physical-chemical property relationship is also considered. The proposed synthesis method enables preparing nanocrystalline fibers and powders with a high degree of dispersion and reactive activity, whose use in composite materials and ceramics improves their service properties.
Asunto(s)
Cerámica/química , Cristalización/métodos , Metales/química , Nanoestructuras/química , Nanoestructuras/ultraestructura , Óxidos/química , Sustancias Macromoleculares/química , Ensayo de Materiales , Conformación Molecular , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
PURPOSE: Heme oxygenase (HO)-1 immunoreactivity (IR) was examined in normal untreated retina and in retinal explants after in vitro treatment with stress agents. METHODS: Enucleated eyes from young adult C3H mice were immediately fixed and cryosectioned and the retina sections processed for immunocytochemistry with antibodies against HO-1 and glial fibrillary acidic protein (GFAP). From other eyes retinas were isolated and maintained in organ culture, either untreated for 4 days maximum or for 21 hours during which the explants were treated the first 3 hours with selected doses of sodium arsenate or hydrogen peroxide. Thereafter, the explants were processed identically with the normal tissue. RESULTS: In the normal retina, HO-1 and GFAP IR was very low. The culturing itself resulted in an increase in both HO-1 and GFAP immunolabeling in Müller cells of explanted retinas. Both sodium arsenate and hydrogen peroxide further induced strong HO-1 IR in Müller cells but not in other retinal cells. In contrast to HO-1, GFAP staining in Müller cells was not altered as a result of treatment, either by sodium arsenate or hydrogen peroxide at any concentration used. CONCLUSIONS: The results show for the first time that HO-1 can be induced in the retina in vitro by conditions of oxidative stress and that enzyme expression is confined exclusively to Müller cells.
Asunto(s)
Células del Tejido Conectivo/enzimología , Hemo Oxigenasa (Desciclizante)/biosíntesis , Estrés Oxidativo , Retina/enzimología , Animales , Arseniatos/farmacología , Células del Tejido Conectivo/efectos de los fármacos , Inducción Enzimática , Proteína Ácida Fibrilar de la Glía/metabolismo , Hemo-Oxigenasa 1 , Peróxido de Hidrógeno/farmacología , Técnicas para Inmunoenzimas , Proteínas de la Membrana , Ratones , Ratones Endogámicos C3H , Técnicas de Cultivo de Órganos , Retina/efectos de los fármacosRESUMEN
We describe the molecular cloning and characterization of a novel myeloid inhibitory siglec, MIS, that belongs to the family of sialic acid-binding immunoglobulin-like lectins. A full-length MIS cDNA was obtained from murine bone marrow cells. MIS is predicted to contain an extracellular region comprising three immunoglobulin-like domains (V-set amino-terminal domain followed by two C-set domains), a transmembrane domain and a cytoplasmic tail with two immunoreceptor tyrosine-based inhibitory motif (ITIM)-like sequences. The closest relative of MIS in the siglec family is human siglec 8. Extracellular regions of these two siglecs share 47% identity at the amino acid level. Southern blot analysis suggests the presence of one MIS gene. MIS is expressed in the spleen, liver, heart, kidney, lung and testis tissues. Several isoforms of MIS protein exist due to the alternative splicing. In a human promonocyte cell line, MIS was able to bind Src homology 2-containing protein-tyrosine phosphatases, SHP-1 and SHP-2. This binding was mediated by the membrane-proximal ITIM of MIS. Moreover, MIS exerted an inhibitory effect on FcgammaRI receptor-induced calcium mobilization. These data suggest that MIS can play an inhibitory role through its ITIM sequences.
Asunto(s)
Antígenos CD/química , Antígenos de Diferenciación de Linfocitos B/química , Proteínas Portadoras/química , Proteínas Portadoras/genética , Lectinas/química , Proteínas de la Membrana/química , Proteínas de la Membrana/genética , Proteínas Tirosina Fosfatasas/metabolismo , Empalme Alternativo , Secuencia de Aminoácidos , Animales , Antígenos CD/metabolismo , Antígenos de Diferenciación de Linfocitos B/metabolismo , Antígenos de Diferenciación Mielomonocítica/química , Northern Blotting , Southern Blotting , Células de la Médula Ósea/metabolismo , Calcio/metabolismo , Proteínas Portadoras/metabolismo , Línea Celular , Membrana Celular/metabolismo , Clonación Molecular , Reactivos de Enlaces Cruzados/farmacología , Citoplasma/metabolismo , ADN Complementario/metabolismo , Humanos , Immunoblotting , Péptidos y Proteínas de Señalización Intracelular , Proteínas de la Membrana/metabolismo , Ratones , Datos de Secuencia Molecular , Ácido N-Acetilneuramínico/metabolismo , Pruebas de Precipitina , Isoformas de Proteínas , Estructura Terciaria de Proteína , Proteína Tirosina Fosfatasa no Receptora Tipo 11 , Proteína Tirosina Fosfatasa no Receptora Tipo 6 , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Homología de Secuencia de Aminoácido , Lectina 3 Similar a Ig de Unión al Ácido Siálico , Distribución Tisular , TransfecciónRESUMEN
PURPOSE: Clusterin has been associated with active cell death in several different model systems, including animal models of retinal degeneration. Clusterin is also expressed in normal tissues, a finding that leads to the question of how it could then play a cell death-specific role during tissue regression. To address this paradox, we have examined clusterin expression during light-induced retinal damage in rats. METHODS: Normal albino rats were reared in darkness and then exposed to intense visible light to induce retinal degeneration. Clusterin expression was then examined at various times after light treatment. Standard molecular techniques including Northern analysis, immunohistochemistry, and Western analysis were employed. RESULTS: Northern analysis established that the largest increase in clusterin expression occurs after a decrease in interphotoreceptor retinoid binding protein, IRBP, expression (an indication of a photoreceptor cell dysfunction) and after an increase in heme oxygenase 1, HO-1, expression (an oxidative stress inducible gene), suggesting that induction of clusterin expression is an oxidative stress response. Immuno-histochemical analysis with two different clusterin-specific antibodies, anti(SGP-2) and anti(301), localized distinct forms of clusterin to Müller cells and degenerating photo-receptor cells. Western analysis demonstrated degeneration associated isoforms of clusterin in light treated retina that are not present in normal retina. CONCLUSION: Clusterin over-expression is characteristic of a retinal degeneration phenotype and we propose that clusterin action may be defined by the nature in which it is modified. We hypothesize that alternate processing leads to retinal degeneration-specific forms of the protein (65, 61, and 50 kDa) that are not present in normal retina.
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Proteínas del Ojo/metabolismo , Glicoproteínas/metabolismo , Chaperonas Moleculares/metabolismo , Traumatismos Experimentales por Radiación/metabolismo , Retina/efectos de la radiación , Degeneración Retiniana/metabolismo , Animales , Northern Blotting , Western Blotting , Clusterina , Adaptación a la Oscuridad , Proteínas del Ojo/genética , Expresión Génica , Glicoproteínas/genética , Hemo Oxigenasa (Desciclizante)/metabolismo , Hemo-Oxigenasa 1 , Técnicas para Inmunoenzimas , Luz , Masculino , Chaperonas Moleculares/genética , Isoformas de Proteínas/metabolismo , ARN Mensajero/metabolismo , Traumatismos Experimentales por Radiación/etiología , Traumatismos Experimentales por Radiación/patología , Ratas , Ratas Sprague-Dawley , Degeneración Retiniana/etiología , Degeneración Retiniana/patología , Proteínas de Unión al Retinol/metabolismoRESUMEN
Activating and inhibitory receptors act in concert to regulate cellular activation. Inhibitory receptors are characterized by the presence of a characteristic sequence known as an immunoreceptor tyrosine-based inhibitory motif (ITIM) in their cytoplasmic tail. Phosphorylated ITIM serve as docking sites for the SH2-containing phosphatases which then inhibit signal transduction. CD33 is a member of the immunoglobulin superfamily and contains two immunoglobulin-like domains, a transmembrane region and a cytoplasmic tail that has two potential ITIM sequences. CD33 expression is restricted to cells of myelomonocytic lineage. The precise function of CD33 is unknown although it is a lectin that binds sialic acid residues in N- and O-glycans on cell surfaces. Co-immunoprecipitation studies demonstrate that CD33 associates with the SH2-containing tyrosine phosphatase SHP-1 in monocytes. The proximal ITIM is necessary and sufficient for SHP-1 binding which is mediated by the aminoterminal SH2 domain. Treatment of SHP-1 with a phosphopeptide representing the proximal CD33 ITIM results in increased SHP-1 enzymatic activity. CD33 exerts an inhibitory effect on tyrosine phosphorylation and Ca(2+) mobilization when co-engaged with the activating FcgammaRI receptor. This data indicates that CD33 is an inhibitory receptor that may regulate FcgammaRI signal transduction.
Asunto(s)
Antígenos CD/metabolismo , Antígenos de Diferenciación Mielomonocítica/metabolismo , Moléculas de Adhesión Celular/metabolismo , Proteínas Tirosina Fosfatasas/metabolismo , Receptores de IgG/metabolismo , Animales , Antígenos CD/genética , Antígenos de Diferenciación Mielomonocítica/genética , Sitios de Unión , Moléculas de Adhesión Celular/genética , Células Cultivadas , Activación Enzimática , Células HL-60 , Humanos , Péptidos y Proteínas de Señalización Intracelular , Ratones , Proteína Tirosina Fosfatasa no Receptora Tipo 11 , Proteína Tirosina Fosfatasa no Receptora Tipo 6 , Proteínas Tirosina Fosfatasas/genética , Proteínas Tirosina Fosfatasas con Dominio SH2 , Lectina 3 Similar a Ig de Unión al Ácido Siálico , Tirosina/metabolismo , Células U937 , Dominios Homologos srcRESUMEN
The binding kinetics of the TCR for its interacting ligand and the nature of the resulting signal transduction event determine the fate of a developing thymocyte. The intracellular tyrosine phosphatase SHP-1 is a potential regulator of the TCR signal transduction cascade and may affect thymocyte development. To assess the role of SHP-1 in thymocyte development, we generated T cell-transgenic mice that express a putative dominant negative form of SHP-1, in which a critical cysteine is mutated to serine (SHP-1 C453S). SHP-1 C453S mice that express the 3.L2 TCR transgene are increased in CD4 single positive cells in the thymus and are increased in cells that express the clonotypic TCR. These data suggest that the expression of SHP-1 C453S results in increased positive selection in 3.L2 TCR-transgenic mice and support a role for SHP-1 thymocyte development.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Proteínas Tirosina Fosfatasas/genética , Receptores de Antígenos de Linfocitos T/metabolismo , Timo/inmunología , Animales , Linfocitos T CD4-Positivos/citología , Cisteína/genética , Péptidos y Proteínas de Señalización Intracelular , Ratones , Ratones Transgénicos , Mutación , Proteína Tirosina Fosfatasa no Receptora Tipo 11 , Proteína Tirosina Fosfatasa no Receptora Tipo 6 , Proteínas Tirosina Fosfatasas con Dominio SH2 , Serina/genética , Transducción de Señal , Bazo/inmunología , Timo/citología , Dominios Homologos srcRESUMEN
An equilibrium between positive and negative regulation of immunoreceptor signaling leads to the proper execution of lymphocyte activation. Tyrosine phosphorylation is the initial event in antigen receptor-induced lymphocyte activation. It is generally accepted that protein tyrosine kinases are involved in positive regulation, whereas protein tyrosine phosphatases are important for the negative regulation of tyrosine phosphorylation-dependent processes. However, the interaction between protein tyrosine kinases and protein tyrosine phosphatases is complex. This article discusses the role of two protein tyrosine phosphatases. CD45 and SHP-1, in the regulation of immunoreceptor signaling. SHP-1 acts as a negative regulator for several immunoreceptors, including those for T- and B-cell antigen receptors. The major role of CD45 is in the positive regulation of T- and B-cell antigen receptor signaling.