RESUMEN
Estimation and prediction ability of linear and threshold models for yearling breed quality score (BQ) and navel development score at weaning (WN) and yearling (YN), considering variances, heritabilities, and rank correlations based on the breeding values predicted for bulls, were compared. Furthermore, it was determined whether BQ, WN, and YN are genetically associated with growth traits (BWG: birth to weaning weight gain, WH: weaning height, WYG: weaning to yearling weight gain, YH: yearling height) to field data of Nelore cattle. For BQ, similar heritabilities were estimated using linear (0.14 ± 0.01) and threshold (0.15 ± 0.02) models. For navel development scores, higher heritability was estimated with threshold (WN 0.22 ± 0.03; YN 0.42 ± 0.03) rather than linear (WN 0.16 ± 0.01; YN 0.29 ± 0.01) models. Rank correlations between sires breeding values predicted for visual scores with linear and threshold models ranging from 0.53 to 0.98, indicating that different sires would be selected using these models, mainly for higher selection intensities. The BQ showed little genetic variability and was not associated with WH and YH. However, low and positive genetic correlations were obtained between BQ with BWG (0.27 ± 0.02) and WYG (0.25 ± 0.02). In general, they are expected low genetic gains for BQ as correlated response to selection based on any of the growth traits studied. The WN showed higher genetic correlation with BWG (0.63 ± 0.02) and WH (0.53 ± 0.02) rather than WYG (-0.06 ± 0.02) and YH (0.26 ± 0.02), indicating that selection for increased growth at weaning (height and weight gain) should lead to longer and most pendulous navels at this age. Weak genetic correlations were obtained between yearling navel and growth traits.
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Bovinos/fisiología , Modelos Genéticos , Carne Roja , Aumento de Peso , Animales , Cruzamiento , Bovinos/crecimiento & desarrollo , Femenino , Masculino , Fenotipo , DesteteRESUMEN
No disponible
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Humanos , Masculino , Recién Nacido , Dacriocistitis/complicaciones , Mucocele/complicaciones , Síndrome de Dificultad Respiratoria del Recién Nacido/etiología , Diagnóstico DiferencialRESUMEN
Insulin signaling is mediated by a complex network of diverging and converging pathways, with alternative proteins and isoforms at almost every step in the process. We show here that insulin activates the transcription of its own gene and that of the beta cell glucokinase gene (betaGK) by different mechanisms. Whereas insulin gene transcription is promoted by signaling through insulin receptor A type (Ex11-), PI3K class Ia, and p70s6k, insulin stimulates the betaGK gene by signaling via insulin receptor B type (Ex11+), PI3K class II-like activity, and PKB (c-Akt). Our data provide evidence for selectivity in insulin action via the two isoforms of the insulin receptor, the molecular basis being preferential signaling through different PI3K and protein kinases.
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Glucoquinasa/genética , Insulina/genética , Insulina/farmacología , Islotes Pancreáticos/efectos de los fármacos , Proteínas Serina-Treonina Quinasas , Receptor de Insulina/metabolismo , Transducción de Señal/efectos de los fármacos , Transcripción Genética/efectos de los fármacos , Bloqueadores de los Canales de Calcio/farmacología , Canales de Calcio Tipo L/metabolismo , Línea Celular , Células Cultivadas , Glucosa/metabolismo , Glucosa/farmacología , Islotes Pancreáticos/enzimología , Islotes Pancreáticos/metabolismo , Modelos Biológicos , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Regiones Promotoras Genéticas/genética , Proteínas Proto-Oncogénicas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-akt , Estabilidad del ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas Quinasas S6 Ribosómicas/antagonistas & inhibidores , Proteínas Quinasas S6 Ribosómicas/metabolismo , Especificidad por SustratoRESUMEN
OBJECTIVE: Nosocomial Candidiasis in low birth weight (LBW) infants have increased. Toxic side effects limit the use of conventional Amphotericin B for treatment of fungal infections. The liposomal forms have lowered this risk considerably, even at higher doses. Our aim was to evaluate treatment response to liposomal Amphotericin B in neonates with Candidiasis. PATIENTS AND METHODS: Fifteen neonates diagnosed both clinically and biologically of Candidiasis infection and who were treated with liposomal Amphotericin B from June 1994 through July 1997 were included. Duration of treatment, when culture became negative, secondary effects, complications, other medication, basal pathology and clinical course were analyzed. RESULTS: Mean gestational age was 36 +/- 6 weeks and 60% were preterm. Mean age at diagnosis was 13.4 days. Eleven patients presented sepsis (1 C. Sp., 9 C. albicans and 1 C. parapsilosis). They were treated with liposomal Amphotericin B, starting dose 0.5-1 mg/kg/day). One patient had associated 5-fluorocytosine. Cultures became negative at approximately 13 days and mean duration of therapy was 21.13 days. Seven patients showed additional bacterial infections. Side effects during treatment were anemia and hypotension. CONCLUSIONS: Liposomal Amphotericin B has been effective in the treatment of Candidiasis without toxic signs that can be attributed solely to the medication.
Asunto(s)
Anfotericina B/administración & dosificación , Antibacterianos/administración & dosificación , Antifúngicos/administración & dosificación , Candidiasis/tratamiento farmacológico , Infección Hospitalaria/tratamiento farmacológico , Factores de Edad , Peso Corporal , Portadores de Fármacos , Quimioterapia Combinada , Flucitosina/administración & dosificación , Edad Gestacional , Humanos , Recién Nacido , Liposomas , Factores de Riesgo , Factores de TiempoRESUMEN
Pancreatic islets of Langerhans are composed of four major endocrine cell types with a smaller number of nonendocrine cells. To study the molecular constituents and function of just one subpopulation of islet cells, it is necessary to sort them from the other cell types. While rat beta-cells can be sorted by autofluorescence-activated flow cytometry, this has not proved possible on a routine and reproducible basis for human beta-cells. In the present study, we have selectively labeled human beta-cells with green fluorescent protein (GFP), allowing for their sorting by flow cytometry. Human islet cells were infected with replication-defective (attenuated) recombinant adenovirus expressing GFP driven by the rat insulin I promoter (Ad-RIP-GFP) for targeted expression in beta-cells, or beta-galactosidase driven by the promiscuous cytomegalovirus (CMV) promoter (Ad-CMV-beta-gal) as control. Whereas the majority of islet cells can be infected by adenovirus, as shown by control infection with Ad-CMV-beta-gal, increased fluorescence after infection with Ad-RIP-GFP was limited to insulin-containing beta-cells. Infection of islet cells with Ad-RIP-GFP resulted reproducibly in the appearance of a population of intensely fluorescent cells, when analyzed by flow cytometry. These cells were sorted using a fluorescence-activated cell sorter (FACS) and shown by immunofluorescence to consist of >95% beta-cells. The targeted expression of GFP thus allows for preparation of human beta-cells purified close to homogeneity. This method should be readily applicable in any laboratory with FACS capability.
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Islotes Pancreáticos/citología , Islotes Pancreáticos/metabolismo , Proteínas Luminiscentes/genética , Adenoviridae/genética , Animales , Separación Celular , Citometría de Flujo , Regulación de la Expresión Génica , Proteínas Fluorescentes Verdes , Humanos , Insulina/genética , Regiones Promotoras Genéticas/genética , Ratas , Proteínas Recombinantes de Fusión/genéticaRESUMEN
Perilipins, a family of phosphoproteins, are specifically located at the surface of intracellular lipid (triacylglycerol) droplets, the site of lipolysis. Stimulation of lipolysis in 3T3-L1 adipocytes by tumor necrosis factor alpha (TNF-alpha) is associated with a decrease in total cellular expression of perilipin A and B, consistent with the hypothesis that a decrease in perilipin protein expression is required for TNF-alpha-induced lipolysis. Adenovirus-mediated overexpression of perilipin A or B maintains perilipin protein levels on the lipid droplet and blocks TNF-alpha-induced lipolysis. In contrast, overexpression of perilipin A or perilipin B does not inhibit isoproterenol-stimulated lipolysis and does not alter the isoproterenol-induced migration of perilipins from the lipid droplet. These results provide the first evidence of how perilipin functions and suggest that TNF-alpha regulates lipolysis, in part, by decreasing perilipin protein levels at the lipid droplet surface.
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Adipocitos/metabolismo , Lipólisis/fisiología , Fosfoproteínas/genética , Factor de Necrosis Tumoral alfa/farmacología , Células 3T3 , Adenoviridae , Adipocitos/citología , Adipocitos/efectos de los fármacos , Animales , Proteínas Portadoras , Regulación de la Expresión Génica/efectos de los fármacos , Isoproterenol/farmacología , Cinética , Lipólisis/efectos de los fármacos , Ratones , Perilipina-1 , Fosfoproteínas/metabolismo , Proteínas Recombinantes/biosíntesis , Transfección , Factor de Necrosis Tumoral alfa/fisiologíaRESUMEN
Insulin production by the pancreatic islet is tightly coupled to the concentration of blood glucose. The mechanism by which glucose controls proinsulin biosynthesis in beta cells is poorly understood. Analysis of insulin gene expression in individual cells within whole, living islets using adenovirus gene transfer and direct observation of insulin promoter-directed green fluorescent protein activity indicates that beta cells are functionally heterogeneous. An increase in glucose concentration not only stimulates expression within individual beta cells, but unexpectedly acts to increase the total number of positive cells. The net islet response to a given glucose stimulus reflects an integrated action of beta cells with individually differing behaviors. This additional level of functional complexity may provide new insights into the pathophysiology and treatment of diabetes mellitus.
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Glucosa/farmacología , Islotes Pancreáticos/efectos de los fármacos , Animales , Línea Celular , Proteínas Fluorescentes Verdes , Humanos , Insulina/genética , Insulina/metabolismo , Secreción de Insulina , Islotes Pancreáticos/citología , Islotes Pancreáticos/metabolismo , Proteínas Luminiscentes/genética , Masculino , Regiones Promotoras Genéticas , Ratas , Ratas Sprague-DawleyRESUMEN
This research explored eldercare among Mexican American primary family caregivers from Dallas and Fort Worth, Texas. Although these caregivers expressed feelings of burden, their ethnocultural values of familism placed burden in a broader cultural context in which caregiving was also viewed as an affirmation and fulfillment of core Mexican American cultural values. Mexican American familism includes expressions of family solidarity, ethnocultural determinants of informal caregiving, distrust of culturally alien institutions (particularly nursing homes), and a desire to care for the elderly within the family context regardless of the personal cost or consequences. In contrast to recent research, these findings suggest that it is premature to dismiss familism as a continuing and central influence in the lives of Mexican American family caregivers.
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Tráquea/anomalías , Femenino , Humanos , Recién Nacido , Radiografía , Tráquea/diagnóstico por imagen , Tráquea/patologíaRESUMEN
The invasin protein of Yersinia pseudotuberculosis binds to integrin receptors on mammalian cells and promotes cellular penetration. We demonstrate here that the cell attachment activity of invasin can be detected in bacterial colonies that have been immobilized on filter membranes. Invasin expressed in either Escherichia coli K-12 or Y. pseudotuberculosis mediated binding to membranes, and as few as 10(5) Y. pseudotuberculosis resulted in detectable attachment of cultured epithelial cells. A similar binding activity was detected in clinical isolates of the related pathogen Y. enterocolitica but not in environmental isolates. Although there exist multiple mechanisms for the binding of wild-type organisms to host cells, efficient mammalian cell binding to immobilized Y. pseudotuberculosis required expression of a functional invasin protein. Several pathogens that are known to bind or penetrate mammalian cells were also tested, and only one of these bound cultured mammalian cells efficiently.
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Adhesinas Bacterianas , Adhesión Bacteriana , Proteínas Bacterianas/metabolismo , Yersinia enterocolitica/patogenicidad , Animales , Células CultivadasRESUMEN
The virally encoded Xis protein is one of the components in the site-specific recombination reactions of bacteriophage lambda. It is required for excisive recombination and inhibits integrative recombination. The mechanism of Xis inhibition of the integration reaction was investigated by methylation protection assays (footprinting analyses) in conjunction with recombination assays. Xis is shown to mediate the formation of a specific attP looped structure involving cooperative and competitive long-range interactions among integrase, integration host factor, and Xis proteins. This higher-order structure precludes supercoiled attP from engaging in the productive partner interactions that lead to execution of the first strand exchange in integrative recombination. In addition to its previously characterized role in excision, Xis-induced DNA bending is postulated to act as a regulatory switch (in an alternative loop mechanism) that converts the attP intasome from an integrative-competent complex to a nonreactive one.
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Bacteriófago lambda/genética , ADN Viral/genética , Proteínas de Escherichia coli , Escherichia coli/genética , Recombinación Genética , Proteínas Virales , Proteínas Bacterianas/metabolismo , Secuencia de Bases , Proteínas Portadoras/metabolismo , ADN Nucleotidiltransferasas/metabolismo , Proteínas de Unión al ADN/metabolismo , Factores de Integración del Huésped , Cinética , Modelos Genéticos , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , PlásmidosRESUMEN
To map the protein-protein and protein-DNA interactions involved in lambda site-specific recombination, Int cleavage assays with suicide substrates, nuclease protection patterns, gel retardation experiments, and quantitative Western blotting were applied to wild-type attL and attL mutants. The results lead to a model in which one IHF molecule bends the attL DNA and forms a higher order complex with the three bivalent Int molecules required for excisive recombination. It is proposed that each of the Int molecules binds in a unique manner: one bridges two DNA binding sites in cis, one is held via its high affinity amino-terminal DNA binding domain, and the third depends upon protein-protein interactions in addition to its low affinity carboxy-terminal DNA binding domain. This protein-DNA complex contains two unsatisfied DNA binding domains, each with a different sequence specificity, and is well suited to specific interactions with an appropriate recombination partner.
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Bacteriófago lambda/genética , ADN Viral/genética , Escherichia coli/genética , Recombinación Genética , Proteínas Virales/genética , Secuencia de Bases , Sitios de Unión , Modelos Estructurales , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Plásmidos , Unión ProteicaRESUMEN
The multiprotein-DNA complexes that participate in bacteriophage lambda site-specific recombination were used to study the combined effect of protein-induced bending and protein-mediated looping of DNA. The protein integrase (Int) is a monomer with two autonomous DNA binding domains of different sequence specificity. Stimulation of Int binding and cleavage at the low affinity core-type DNA sites required interactions with the high affinity arm-type sites and depended on simultaneous binding of the sequence-specific DNA bending protein IHF (integration host factor). The bivalent DNA binding protein is positioned at high affinity sites and directed, by a DNA bending protein, to interactions with distant lower affinity sites. Assembly of this complex is independent of protein-protein interactions.
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Proteínas Bacterianas/farmacología , Bacteriófago lambda/genética , ADN Nucleotidiltransferasas/metabolismo , ADN Bacteriano/metabolismo , ADN Viral/metabolismo , Conformación de Ácido Nucleico/efectos de los fármacos , Proteínas Bacterianas/metabolismo , Bacteriófago lambda/enzimología , Sitios de Unión , Enzimas de Restricción del ADN , Elementos Transponibles de ADN , ADN Bacteriano/genética , ADN Viral/genética , Proteínas de Unión al ADN/metabolismo , Integrasas , Factores de Integración del Huésped , Mutación , Recombinación GenéticaRESUMEN
The 40 kd lambda Integrase protein is shown to contain two autonomous DNA binding domains with different sequence specificities. Competition experiments in which the binding activity of Int is assayed through nuclease protection demonstrate the functional independence of the two DNA recognition specificities. Proteolytic cleavage of Int and footprinting analysis of the resulting two major peptides allow the physical separation and identification of two DNA binding domains: an amino-terminal peptide that interacts with "arm-type" sites and a carboxy-terminal peptide that binds to "core-type" sequences. In addition, the data suggest that the two domains can bind DNA simultaneously, consistent with a model in which Integrase would link two disparate DNA sequences.
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Bacteriófago lambda/enzimología , ADN Nucleotidiltransferasas/metabolismo , Proteínas de Unión al ADN/metabolismo , Secuencia de Aminoácidos , Secuencia de Bases , Sitios de Unión , Unión Competitiva , Quimotripsina , Enzimas de Restricción del ADN , ADN Recombinante/metabolismo , Desoxirribonucleasas , Integrasas , Modelos Genéticos , PlásmidosRESUMEN
High levels of covalent integrase-DNA complexes accumulate when suicide substrates containing a medial nick within the overlap region are nicked by lambda integrase protein. The tyrosine residue at position 342 is shown to form a covalent bond with DNA at the sites of strand exchange. A mutant integrase in which this tyrosine is changed to phenylalanine is devoid of both topoisomerase and recombinase activity but still binds to both core- and arm-type DNA binding sites with an affinity comparable to wild-type integrase. Tyrosine-342 is located within a 40-amino acid region that is conserved among 15 known recombinases comprising the "integrase family." The present results show that this small region of homology participates in catalysis of strand transfer.
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ADN Nucleotidiltransferasas/metabolismo , ADN/metabolismo , Tirosina/metabolismo , Secuencia de Aminoácidos , Sitios de Unión , ADN-Topoisomerasas de Tipo I/metabolismo , Integrasas , Datos de Secuencia MolecularAsunto(s)
Niño , Enfermedad Crónica , Factores de Edad , Niño Institucionalizado , Preescolar , Emociones , Femenino , Humanos , Masculino , Relaciones Padres-Hijo , Psicología Infantil , Relaciones entre HermanosRESUMEN
Here we characterize FIS (factor for inversion stimulation), a new cellular component of the lambda site-specific recombination pathway. This host protein binds to a specific region in the lambda attP overlapping the Xis binding sites and can bind cooperatively with Xis to these sites. FIS stimulates lambda excision up to 20-fold in vitro in the presence of suboptimal Xis concentrations, but has no effect in the presence of saturating Xis; FIS has no effect on integrative recombination. FIS can replace one Xis molecule in a series of cooperative and competitive interactions but cannot carry out excision in the absence of Xis. FIS's role in the regulation of recombination has been inferred from in vivo modification of DNA. In exponentially growing cells the lambda FIS site is fully occupied, whereas in stationary-phase cells this binding site is vacant.
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Bacteriófago lambda/fisiología , Proteínas de Unión al ADN/fisiología , Escherichia coli/fisiología , Recombinación Genética , Activación Viral , Secuencia de Bases , Sitios de Unión , División Celular , ADN Viral/metabolismo , Lisogenia , Proteínas Virales/fisiologíaRESUMEN
The highly directional site-specific recombination of bacteriophage lambda is tightly regulated by the binding of three different proteins to a complex array of sites. The manner in which these reactions are both stimulated and inhibited by co-operative binding of proteins to specific sites on the P arm of attP and AttR has been elucidated by correlation of nuclease protection with recombination studies of both wild-type and mutant DNAs. In addition to co-operative forces, there is a specific competitive interaction that allows the protein-DNA complex to serve as a "biological switch". This switch does not depend upon the simple occlusion of DNA binding sites by neighboring proteins; but, rather, the outcome of this competition is dependent on long-range interactions that vary between the higher-order structures of attP and attR. These higher-order structures are dependent on cooperative interactions involving three proteins binding to five or more sites.
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Bacteriófago lambda/genética , ADN Recombinante/metabolismo , ADN Viral/metabolismo , Proteínas Virales/metabolismo , Sitio Alostérico , Proteínas Bacterianas/metabolismo , Sitios de Unión , Proteínas de Unión al ADN/metabolismo , Factores de Integración del Huésped , Mutación , Proteínas del Núcleo Viral/metabolismoRESUMEN
The manner in which integration host factor (IHF) regulates lambda site-specific recombination has been analyzed by examining the behavior of both wild-type and mutant DNAs in integrative and excisive recombination as well as in protein binding. While integrative recombination of an attP with two base changes in the H1 site required 8-fold more IHF than did wild type, binding to this site was lowered at least 500-fold, suggestive of cooperative interactions. A mutant attP with nine base changes did not integrate at all in vitro, with the defect being less severe in vivo. IHF inhibition of excisive recombination was relieved by both mutations in vitro and in vivo. These results imply that occupancy of the H1 site is critical for determining the direction of recombination. It is proposed that IHF inhibition of excision provides a monitor of the strength of the induction stimulus and the nutritional state of the cell; this would allow the prophage to excise selectively in conditions which favor successful completion of the lytic cycle.