PETAL LOSS, a trihelix transcription factor gene, regulates perianth architecture in the Arabidopsis flower

Perianth development is specifically disrupted in mutants of the PETAL LOSS (PTL) gene, particularly petal initiation and orientation. We have cloned PTL and show that it encodes a plant-specific trihelix transcription factor, one of a family previously known only as regulators of light-controlled genes. PTL transcripts were detected in the early-developing flower, in four zones between the initiating sepals and in their developing margins. Strong misexpression of PTL in a range of tissues universally results in inhibition of growth, indicating that its normal role is to suppress growth between initiating sepals, ensuring that they remain separate. Consistent with this, sepals are sometimes fused in ptl single mutants, but much more frequently in double mutants with either of the organ boundary genes cup-shaped cotyledon1 or 2. Expression of PTL within the newly arising sepals is apparently prevented by the PINOID auxin-response gene. Surprisingly, PTL expression could not be detected in petals during the early stages of their development, so petal defects associated with PTL loss of function may be indirect, perhaps involving disruption to signalling processes caused by overgrowth in the region. PTL-driven reporter gene expression was also detected at later stages in the margins of expanding sepals, petals and stamens, and in the leaf margins; thus, PTL may redundantly dampen lateral outgrowth of these organs, helping define their final shape.

A luz para além do visível

Com este breve estudo tentaremos mostrar como a leitura que fazemos da luz visível e invisível não depende apenas da capacidade dos dispositivos técnico-científicos de captar mais além e melhor a luz que nos chega de longe, mas depende também da consciência que fazemos de nós mesmos, enquanto habitantes de um determinado lugar e de um determinado tempo, com determinadas coordenadas em relação ao mundo.

Noves aportacions a l'arbre genealògic de la família Montcada, senyors de la Baronia d'Aitona

Montcada’s family had in Middle Ages the Baronia d’Aitona in the land known as Baix Segre, in Lleida. His properties included the villages of Serós, Aitona, Mequinensa, Faió, Vallobar and Maials. This part of the family, who lived in Lleida, is really unknown. Documents from the Arxiu Ducal de Medinaceli a Catalunya have shown new members of this part of the family unknown since now. This new information has allowed to complete the genealogical trees of the Montcada’s family in Lleida.

Convivencia y mejora de las relaciones en el aula.

Materiales didácticos en Power-Point secuenciando actividades para trabajar con el alumnado respecto a comportamientos asertivos- comportamientos no asertivos,educando en la convivencia y mejora de las relaciones personales, previniendo la violencia y reduciendo el absentismo escolar utilizando el material informático.

Geometría en los Reales Alcázares de Sevilla.

Se presenta para el alumnado el aprendizaje de la geometría, y propone abordar la enseñanza de este bloque mediante unidades didácticas interdisciplinares, apoyadas en el entorno cultural y con contenidos y actividades adaptadas a distintos niveles de la ESO y de ritmos de aprendizaje en el aula. Se contempla la creación de materiales didácticos para todos los cursos de la ESO, su aplicación en el aula y la evaluación de los resultados obtenidos.

Campo de acción de los sindicatos dentro de la organización escolar y de la formación de los profesores.

Pretende, dada la legislación educativa y sindical vigente, destacar la labor que realizan y pueden realizar los sindicatos de la enseñanza, apoyando al profesorado de todos los niveles y etapas, dentro del sistema educativo y, como profesionales implicados, en la planificación y desarrollo de la formación inicial y permanente del profesorado. Para situar a los sindicatos de la enseñanza se ha realizado un recorrido por la historia de las organizaciones internacionales y españolas hasta llegar a los sindicatos de la enseñanza actuales, y para comprender sus reivindicaciones y propuestas, un estudio del sistema educativo español actual, con la implicación de la reforma, las principales leyes educativas y los planes de formación de los profesores. Estudia la opinión del profesorado sobre los sindicatos españoles y el grado de conocimiento que los representantes sindicales tienen de las reivindicaciones del profesorado. El estudio sigue el método histórico. La función de los sindicatos debe ser actualizada.

Organotin compounds in the Paranagua Estuarine Complex, Parana, Brazil: Evaluation of biological effects, surface sediment, and suspended particulate matter

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A novel xylan degrading beta-D-xylosidase: purification and biochemical characterization

Aspergillus ochraceus, a thermotolerant fungus isolated in Brazil from decomposing materials, produced an extracellular beta-xylosidase that was purified using DEAE-cellulose ion exchange chromatography, Sephadex G-100 and Biogel P-60 gel filtration. beta-xylosidase is a glycoprotein (39 % carbohydrate content) and has a molecular mass of 137 kDa by SDS-PAGE, with optimal temperature and pH at 70 A degrees C and 3.0-5.5, respectively. beta-xylosidase was stable in acidic pH (3.0-6.0) and 70 A degrees C for 1 h. The enzyme was activated by 5 mM MnCl2 (28 %) and MgCl2 (20 %) salts. The beta-xylosidase produced by A. ochraceus preferentially hydrolyzed p-nitrophenyl-beta-d-xylopyranoside, exhibiting apparent K-m and V-max values of 0.66 mM and 39 U (mg protein)(-1) respectively, and to a lesser extent p-nitrophenyl-beta-d-glucopyranoside. The enzyme was able to hydrolyze xylan from different sources, suggesting a novel beta-d-xylosidase that degrades xylan. HPLC analysis revealed xylans of different compositions which allowed explaining the differences in specificity observed by beta-xylosidase. TLC confirmed the capacity of the enzyme in hydrolyzing xylan and larger xylo-oligosaccharides, as xylopentaose.