Asunto(s)
Computadores , Atención a la Salud/tendencias , Atención de Enfermería , Enfermería , Canadá , Humanos , Saskatchewan , Sociedades de EnfermeríaRESUMEN
Medium chain hydrolase (MCH) is an enzyme which regulates the chain length of fatty acid synthesis specifically in the mammary gland of the rat. During lactation, MCH interacts with fatty acid synthase (FAS) to cause premature release of acyl chains, thus providing medium chain fatty acids for synthesis of milk fat. In this study we have investigated the ability of rat MCH to interact with the phylogenetically more distant FAS structure present in plant systems and to cause a perturbation of fatty acid synthesis. In in vitro experiments, addition of purified MCH to rapeseed homogenates was found to cause a significant perturbation of fatty acid synthesis towards medium chain length products. The rat MCH gene was expressed in transgenic oilseed rape using a seed specific rape acyl carrier protein (ACP) promoter and a rape ACP plastid targeting sequence. Western analysis showed MCH protein to be present in transgenic seed and for its expression to be developmentally regulated in concert with storage lipid synthesis. The chimaeric preprotein was correctly processed and immunogold labelling studies confirmed MCH to be localized within plastid organelles. However, fatty acid analysis of oil from MCH-expressing rape seed showed no significant differences to that from control seed.
Asunto(s)
Brassica/genética , Ácido Graso Sintasas/genética , Regulación Enzimológica de la Expresión Génica , Plantas Modificadas Genéticamente/genética , Tioléster Hidrolasas/genética , Animales , Western Blotting , Electroforesis en Gel de Poliacrilamida , Ácido Graso Sintasas/metabolismo , Ácido Graso Sintasas/ultraestructura , Microscopía Inmunoelectrónica , Ratas , Semillas/química , Tioléster Hidrolasas/metabolismo , Tioléster Hidrolasas/ultraestructuraRESUMEN
A novel xyloglucan-specific endo-(1-->4)-beta-D-glucanase, involved in the post-germinative mobilization of xyloglucan storage reserves, has previously been isolated from nasturtium (Tropaeolum majus L.) seed. Its mode of action has been shown, in vitro, to be one of transglycosylation except at low substrate (glycosylacceptor) concentrations when hydrolysis predominates. Here it is shown that this nasturtium seed xyloglucan endo-transglycosylase is encoded by a single gene which is transcribed and processed to a 1.5 kb mRNA. The isolation and DNA sequence analysis of a cDNA copy of the nasturtium xyloglucan endo-transglycosylase transcript is described. The cDNA encodes a 33.5 kDa precursor polypeptide which is subsequently processed to a 31 kDa mature protein. The precursor incorporates an N-terminal signal sequence which probably contains information relevant to the targeting of the enzyme to the cell wall. The computer-predicted isoelectric point (5.14) and low (approximately 0%) alpha-helix content of the deduced mature protein are in excellent agreement with the experimental data obtained using the purified enzyme. The deduced protein sequence lacks homology with known plant endo-(1-->4)-beta-D-glucanases, consistent with the unique properties of the enzyme. Database searches have revealed that a Brassica protein (meri-5) of previously unknown function, but abundantly expressed in expanding tissue, shares structural identity with the nasturtium xyloglucan endo-transglycosylase. The expression of a xyloglucan endo-transglycosylase in expanding tissue would be consistent with the contention that enzymes of this type are involved in cell wall loosening.
Asunto(s)
Glicosiltransferasas/genética , Plantas/enzimología , Secuencia de Aminoácidos , Aminoácidos/análisis , Secuencia de Bases , Dicroismo Circular , ADN , Precursores Enzimáticos/aislamiento & purificación , Expresión Génica , Genes de Plantas , Glicosiltransferasas/química , Glicosiltransferasas/metabolismo , Datos de Secuencia Molecular , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas/genética , Pruebas de Precipitina , ARN Mensajero/metabolismo , Semillas/enzimología , Homología de Secuencia de AminoácidoRESUMEN
Genomic Southern blot analysis of Brassica napus DNA indicates that seed-expressed acyl carrier protein (ACP) is encoded by a multigene family of some 35 genes/haploid genome. Two genomic clones encoding B. napus ACP have been isolated and sequenced. The coding sequences of the 2 respective genes were found to be perfectly homologous to 2 distinct B. napus seed-expressed cDNAs and therefore represent seed-expressed forms of ACP. The 2 genomic ACP sequences share 94% homology within their coding sequences. Both genes are interrupted by 3 intervening sequences whose position within the 2 coding sequences is conserved. RNase protection studies were used to map the transcription start site of one of the genes and to provide further evidence that the gene is seed-expressed. The expression of a sub-group of the ACP gene family was found to be developmentally regulated in concert with the storage lipid synthetic phase of seed development. The coding sequence of both B. napus genes are highly homologous (96% and 93% respectively) to a Brassica campestris ACP cDNA sequence, suggesting that they may have evolved from this ancestral gene.
Asunto(s)
Proteína Transportadora de Acilo/genética , Genes de Plantas , Plantas/genética , Secuencia de Aminoácidos , Secuencia de Bases , Brassica/genética , Clonación Molecular , ADN/genética , Expresión Génica , Datos de Secuencia Molecular , Familia de Multigenes , Proteínas de Plantas/genética , Mapeo Restrictivo , Semillas/genética , Transcripción GenéticaRESUMEN
The antidepressant efficacy, influence on sleep variables and incidence of side-effects of trazodone (100-400 mg daily), given either as a single night-time dose or thrice daily, were compared in a double-blind, 4 week, parallel group, multicentre hospital study. Of 56 patients who entered the study, full data was available for 37, of whom 20 took the medication at night and the other 17 received divided doses during the day. The results showed equivalent therapeutic efficacy for the two dosage regimens and tolerance was good in both groups. For onset and also duration of sleep, significantly more patients in the single night-time group improved than worsened in response. Both groups of patients tended to report a more satisfying sleep and greater freshness on waking, although these latter effects were not statistically significant. For the group taking trazodone thrice daily, there was a trend for more complaints of side-effects, particularly dry mouth, headache and drowsiness which led to more of these patients requiring modification of dosage. Thus trazodone appears to have clinically useful sedative properties. It has relatively few side-effects and these are generally reduced by giving a single dose at night.
Asunto(s)
Trastorno Depresivo/tratamiento farmacológico , Piperazinas/administración & dosificación , Trazodona/administración & dosificación , Adolescente , Adulto , Anciano , Presión Sanguínea/efectos de los fármacos , Esquema de Medicación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Escalas de Valoración Psiquiátrica , Trazodona/efectos adversos , Trazodona/uso terapéuticoRESUMEN
To assess the prevalence of alcoholism among people admitted to hospital 303 patients completed a drinking questionnaire. A total of 59 (19.5%) were found to have a drinking problem, which constituted a sixfold greater prevalence than recorded in a community survey using the same technique. The drinkers were mostly men and tended to be younger than the non-drinkers and to smoke more heavily, live in more crowded conditions, and be of lower social class. Significantly more of the drinkers had at least one parent who was an alcoholic. The results confirm that hospital inpatients comprise a larger proportion of alcoholics than found in the general population. Hence medical staff should be alert to such patients, so that treatment may be initiated at an early stage of social decompensation.
