RESUMO
Sulfur (S) is an essential macronutrient for plants and its availability in soils is an important determinant for growth and development. Current regulatory policies aimed at reducing industrial S emissions together with changes in agronomical practices have led to a decline in S contents in soils worldwide. Deficiency of sulfate-the primary form of S accessible to plants in soil-has adverse effects on both crop yield and nutritional quality. Hence, recent research has increasingly focused on unraveling the molecular mechanisms through which plants detect and adapt to a limiting supply of sulfate. A significant part of these studies involves the use of omics technologies and has generated comprehensive catalogs of sulfate deficiency-responsive genes and processes, principally in Arabidopsis together with a few studies centering on crop species such as wheat, rice, or members of the Brassica genus. Although we know that sulfate deficiency elicits an important reprogramming of the transcriptome, the transcriptional regulators orchestrating this response are not yet well understood. In this review, we summarize our current knowledge of gene expression responses to sulfate deficiency and recent efforts towards the identification of the transcription factors that are involved in controlling these responses. We further compare the transcriptional response and putative regulators between Arabidopsis and two important crop species, rice and tomato, to gain insights into common mechanisms of the response to sulfate deficiency.
Assuntos
Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Sulfatos , Sulfatos/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Oryza/genética , Oryza/metabolismo , Oryza/crescimento & desenvolvimentoRESUMO
Enhancing grain yield is a primary goal in the cultivation of major staple crops, including wheat. Recent research has focused on identifying the physiological and molecular factors that influence grain weight, a critical determinant of crop yield. However, a bottleneck has arisen due to the trade-off between grain weight and grain number, whose underlying causes remain elusive. In a novel approach, a wheat expansin gene, TaExpA6, known for its expression in root tissues, was engineered to express in the grains of the spring wheat cultivar Fielder. This modification led to increases in both grain weight and yield without adversely affecting grain number. Conversely, a triple mutant line targeting the gene TaGW2, a known negative regulator of grain weight, resulted in increased grain weight but decreased grain number, potentially offsetting yield gains. This study aimed to evaluate the two aforementioned modified wheat genotypes (TaExpA6 and TaGW2) alongside their respective wild-type counterparts. Conducted in southern Chile, the study employed a Complete Randomized Block Design with four replications, under well-managed field conditions. The primary metrics assessed were grain yield, grain number, and average grain weight per spike, along with detailed measurements of grain weight and dimensions across the spike, ovary weight at pollination (Waddington's scale 10), and post-anthesis expression levels of TaExpA6 and TaGW2. Results indicated that both the TaExpA6 and the triple mutant lines achieved significantly higher average grain weights compared to their respective wild types. Notably, the TaExpA6 line did not exhibit a reduction in grain number, thereby enhancing grain yield per spike. By contrast, the triple mutant line showed a reduced grain number per spike, with no significant change in overall yield. TaExpA6 expression peaked at 10 days after anthesis (DAA), and its effect on grain weight over the WT became apparent after 15 DAA. In contrast, TaGW2 gene disruption in the triple mutant line increased ovary size at anthesis, leading to improved grain weight above the WT from the onset of grain filling. These findings suggest that the trade-off between grain weight and number could be attributed to the overlapping of the critical periods for the determination of these traits.
RESUMO
La evaluación de la satisfacción de los pacientes permite por un lado identificar aquellas áreas deficitarias desde el punto de vista del paciente y por otra parte nos sirve para evaluar los resultados de los cuidados, ya que las necesidades del paciente son el eje sobre el que se articulan las prestaciones asistenciales. Los objetivos son: 1. Determinar el grado de satisfacción de los pacientes en hemodiálisis crónica en relación con la atención recibida y 2. Conocer los aspectos del proceso asistencial que generan mayor satisfacción e identificar oportunidades de mejora. Estudio descriptivo transversal a todos los pacientes en tratamiento con hemodiálisis crónica de la unidad de HD del hospital de referencia para nefrología del Área 8 de la Comunidad de Madrid, entre marzo y abril de 2004. Se administró el cuestionario SERVQHOS modificado. Cada ítem se puntuó en una escala Likert (de 1 a 5) según el grado de satisfacción. Para el análisis de datos se utilizó el programa SPSS. Se utilizó el Alpha de Cronbach para el análisis de fiabilidad. La muestra la constituyeron 61 cuestionarios con una tasa de respuesta del 98,3%. 51,8% de los pacienteseran hombres y el 48,2% mujeres. Edad media 71,18 ±13,3 años. La puntuación media obtenida en la primera parte del cuestionario fue superior a 3,5 en todos los atributos analizados excepto en la facilidad para llegar al hospital. Los atributos con los que los pacientes están menos satisfechos son el tiempo de espera para ser atendidos por el médico, la facilidad de llegada al hospital y la comunicación que el personal de la unidad mantiene con los familiares. Los aspectos que influyen en la satisfacción de los pacientes son la puntualidad de las sesiones de hemodiálisis, la rapidez con que consigue lo que necesita, el interés del personal de enfermería por los pacientes y el tiempo de espera para ser atendido por el médico. La satisfacción media global fue de 3,81. No se encontró correlación entrelas variables sociodemográficas y el nivel de satisfacción
The evaluation of patient satisfaction enables the deficient areas to be identified from the patients point of view, and also helps us to evaluate the results of the care, as patient needs are the axis on which the care service is based. The objectives are the following: 1. to determine the satisfaction of patients in chronic haemodialysis with the attention they receive, and 2. to know the aspects of the care process that cause greatest satisfaction and to identify opportunities for improvement. A transversal descriptive study of all patients with chronic haemodialysis in the HD unit of the referred hospital for nephrology of Area 8 of Madrid Community between March and April 2004. The modified SERVQHOS questionnaire was administered. Each item was scored on a Likert scale (1 to 5) according to the degree of satisfaction. The SPSS programme was used for data analysis. The Cronbach Alpha was used to analyse the reliability. The sample comprised 61 questionnaires with a reply rate of 98.3%.51.8% of the patients were men and 48.2% women. Average age 71.18 ± 13.3.The average score achieved in the first part of the questionnaire was over 3.5 in all attributes analysed except for ease for arriving at the hospital. The attributes with which patients are least satisfied are the waiting time to be attended by the doctor, ease of arriving at the hospital and the communication of the unit personnel with the relatives. The aspects influencing the satisfaction of the patients are the punctuality in the haemodialysis sessions, the speed with which we get what we want, the interest of the nursing staff in the patients and the waiting time to be attended by a doctor. The average overall satisfaction was 3.81. No correlation was found between the socio-demographic variables and the degree of satisfaction