Is callose a barrier for lead ions entering Lemna minor L. root cells?

Plants have developed a range of strategies for resisting environmental stresses. One of the most common is the synthesis and deposition of callose, which functions as a barrier against stress factor penetration. The aim of our study was to examine whether callose forms an efficient barrier against Pb penetration in the roots of Lemna minor L. exposed to this metal. The obtained results showed that Pb induced callose synthesis in L. minor roots, but it was not deposited regularly in all tissues and cells. Callose occurred mainly in the protoderm and in the centre of the root tip (procambial central cylinder). Moreover, continuous callose bands, which could form an efficient barrier for Pb penetration, were formed only in the newly formed and anticlinal cell walls (CWs); while in other CWs, callose formed only small clusters or incomplete bands. Such an arrangement of callose within root CWs inefficiently protected the protoplast from Pb penetration. As a result, Pb was commonly present inside the root cells. In the light of the results, the barrier role of callose against metal ion penetration appears to be less obvious than previously believed. It was indicated that induction of callose synthesis is not enough for a successful blockade of the stress factor penetration. Furthermore, it would appear that the pattern of callose distribution has an important role in this defence strategy

ANK, a Host Cytoplasmic Receptor for the Tobacco mosaic virus Cell-to-Cell Movement Protein, Facilitates Intercellular Transport through Plasmodesmata

Plasmodesma (PD) is a channel structure that spans the cell wall and provides symplastic connection between adjacent cells. Various macromolecules are known to be transported through PD in a highly regulated manner, and plant viruses utilize their movement proteins (MPs) to gate the PD to spread cell-to-cell. The mechanism by which MP modifies PD to enable intercelluar traffic remains obscure, due to the lack of knowledge about the host factors that mediate the process. Here, we describe the functional interaction between Tobacco mosaic virus (TMV) MP and a plant factor, an ankyrin repeat containing protein (ANK), during the viral cell-to-cell movement. We utilized a reverse genetics approach to gain insight into the possible involvement of ANK in viral movement. To this end, ANK overexpressor and suppressor lines were generated, and the movement of MP was tested. MP movement was facilitated in the ANK-overexpressing plants, and reduced in the ANK-suppressing plants, demonstrating that ANK is a host factor that facilitates MP cell-to-cell movement. Also, the TMV local infection was largely delayed in the ANK-suppressing lines, while enhanced in the ANK-overexpressing lines, showing that ANK is crucially involved in the infection process. Importantly, MP interacted with ANK at PD. Finally, simultaneous expression of MP and ANK markedly decreased the PD levels of callose, β-1,3-glucan, which is known to act as a molecular sphincter for PD. Thus, the MP-ANK interaction results in the downregulation of callose and increased cell-to-cell movement of the viral protein. These findings suggest that ANK represents a host cellular receptor exploited by MP to aid viral movement by gating PD through relaxation of their callose sphincters

Depression, anxiety and telomere length in young adults: evidence from the National Health and Nutrition Examination Survey

Telomere length has been hypothesized to be a marker of cumulative exposure to stress, and stress is an established cause of depression and anxiety disorders. The aim of this study was to examine the relationship between depression, anxiety and telomere l

Grau de satisfação de usuários de um hospital privado Grado de satisfacción de usuarios de un hospital privado Degree of satisfaction of users of a private hospital

OBJETIVOS: Conhecer o grau de satisfação dos usuários de um hospital privado e os fatores intervenientes nessa satisfação, baseado no modelo de Parasuraman, Zeithaml e Berry. MÉTODOS: Estudo exploratório descritivo de abordagem quantitativa realizado em um hospital privado com amostra constituída de 288 usuários. A coleta dos dados ocorreu de abril a julho de 2009, por meio de um questionário e a análise estatística descritiva e inferencial. RESULTADOS: Identificaram os níveis de satisfação dos usuários, bem como as dimensões com maior escore: garantia e confiabilidade e com menor escore: responsividade e empatia. As equipes de enfermagem e médica obtiveram as maiores pontuações. CONCLUSÕES: Observou-se a necessidade de intervenção nas áreas de nutrição e atendimento inicial. Assim, este estudo propiciou um diagnóstico multissetorial, subsidiando os gestores da instituição na revisão de processos assistenciais e gerenciais.<br>OBJETIVOS: Conocer el grado de satisfacción de usuarios de un hospital privado y los factores intervenientes en esa satisfacción, basado en el modelo de Parasuraman, Zeithaml y Berry. MÉTODOS: Estudio exploratorio descriptivo de abordaje cuantitativo realizado en un hospital privado con una muestra constituida por 288 usuarios. La recolección de los datos ocurrió de abril a julio de 2009, por medio de un cuestionario y el análisis estadístico descriptivo e inferencial. RESULTADOS: se identificaron los niveles de satisfacción de los usuarios, así como las dimensiones con mayor score: garantia y confiabilidad y con menor score: receptividad y empatía. Los equipos de enfermería y médica obtuvieron las mayores puntuaciones. CONCLUSIONES: Se observó la necesidad de intervención en las áreas de nutrición y atención inicial. Así, este estudio propició un diagnóstico multisectorial, subsidiando a los gestores de la institución en la revisión de procesos asistenciales y gerenciales.<br>OBJECTIVES: To know the degree of satisfaction of users of a private hospital and the factors involved in this satisfaction, based on the model of Parasuraman, Zeithaml and Berry. METHODS: A descriptive, exploratory, quantitative study conducted in a private hospital with a sample consisting of 288 users. Data collection occurred between April to July 2009, by means of a questionnaire and analysis using descriptive and inferential statistics. RESULTS: We identified levels of user satisfaction, and the dimensions with the highest scores: security and reliability, and with lower scores, responsiveness and empathy. The nursing and medical teams had the highest scores. CONCLUSIONS: There is a need for intervention in the areas of nutrition and initial care. Thus, this study provided a multisectoral diagnosis, assisting managers in reviewing the institution's clinical and managerial processes