Phytochrome B binds with greater apparent affinity than phytochrome A to the basic helix–loop–helix factor PIF3 in a reaction requiring the PAS domain of PIF3

The signaling pathways by which the phytochrome (phy) family of photoreceptors transmits sensory information to light-regulated genes remain to be fully defined. Evidence for a relatively direct pathway has been provided by the binding of one member of the family, phyB, to a promoter-element-bound, basic helix–loop–helix protein, PIF3, specifically upon light-induced conversion of the photoreceptor molecule to its biologically active conformer (Pfr). Here, we show that phyA also binds selectively and reversibly to PIF3 upon photoconversion to Pfr, but that the apparent affinity of PIF3 for phyA is 10-fold lower than for phyB. This result is consistent with previous in vivo data from PIF3-deficient Arabidopsis, indicating that PIF3 has a major role in phyB signaling, but a more minor role in phyA signaling. We also show that phyB binds stoichiometrically to PIF3 at an equimolar ratio, suggesting that the resultant complex is the unit active in transcriptional regulation at target promoters. Deletion mapping suggests that a 37-aa segment present at the N terminus of phyB, but absent from phyA, contributes strongly to the high binding affinity of phyB for PIF3. Conversely, deletion mapping and point mutation analysis of PIF3 for determinants involved in recognition of phyB indicates that the PAS domain of PIF3 is a major contributor to this interaction, but that a second determinant in the C-terminal domain is also necessary.

Complete genome sequence of Caulobacter crescentus

The complete genome sequence of Caulobacter crescentus was determined to be 4,016,942 base pairs in a single circular chromosome encoding 3,767 genes. This organism, which grows in a dilute aquatic environment, coordinates the cell division cycle and multiple cell differentiation events. With the annotated genome sequence, a full description of the genetic network that controls bacterial differentiation, cell growth, and cell cycle progression is within reach. Two-component signal transduction proteins are known to play a significant role in cell cycle progression. Genome analysis revealed that the C. crescentus genome encodes a significantly higher number of these signaling proteins (105) than any bacterial genome sequenced thus far. Another regulatory mechanism involved in cell cycle progression is DNA methylation. The occurrence of the recognition sequence for an essential DNA methylating enzyme that is required for cell cycle regulation is severely limited and shows a bias to intergenic regions. The genome contains multiple clusters of genes encoding proteins essential for survival in a nutrient poor habitat. Included are those involved in chemotaxis, outer membrane channel function, degradation of aromatic ring compounds, and the breakdown of plant-derived carbon sources, in addition to many extracytoplasmic function sigma factors, providing the organism with the ability to respond to a wide range of environmental fluctuations. C. crescentus is, to our knowledge, the first free-living α-class proteobacterium to be sequenced and will serve as a foundation for exploring the biology of this group of bacteria, which includes the obligate endosymbiont and human pathogen Rickettsia prowazekii, the plant pathogen Agrobacterium tumefaciens, and the bovine and human pathogen Brucella abortus.

The Small, Methionine-Rich Chloroplast Heat-Shock Protein Protects Photosystem II Electron Transport during Heat Stress1

Evidence suggests that the small chloroplast heat-shock protein (Hsp) is involved in plant thermotolerance but its site of action is unknown. Functional disruption of this Hsp using anti-Hsp antibodies or addition of purified Hsp to chloroplasts indicated that (a) this Hsp protects thermolabile photosystem II and, consequently, whole-chain electron transport during heat stress; and (b) this Hsp completely accounted for heat acclimation of electron transport in pre-heat-stressed plants. Therefore, this Hsp is a major adaptation to acute heat stress in plants.

James Turrell and the Northern romantic tradition

"This paper discusses the work of contemporary artist James Turrell as framed by the philosophy of the sublime. Focusing on the artist’s use of the medium of light, it addresses Turrell’s scientific approach to creating artworks and discusses his resolution of the problematic relationship between science and spirituality. This relationship is discussed through the examination of the artist’s use of total visual fields known as ganzfelden and other perceptual phenomena, such as those encountered while piloting aircraft"

Exception or extension? : reorienting the Peacock Room among James McNeill Whistler's interior designs

"Although famous for his paintings and etchings today, James McNeill Whistler (1834-1903) was also an important interior designer in the nineteenth-century British Aesthetic movement. Whistler‘s most famous and only extant interior design is Harmony in Blue and Gold: The Peacock Room (1876-77). It is also his most puzzling interior. Long considered an exception to the rule of Whistler‘s other interiors, the Peacock Room has often been overlooked in the few studies of the artist‘s interior designs"

Raluca L. Radulescu and Cory James Rushton, eds. 2009: A Companion to Medieval Popular Romance. Studies in Medieval Romance 10. Cambridge: D. S. Brewer. XIV + 209 pp. ISBN 9781843841920

This review is part of a research project funded by the Spanish Ministry of Science and Innovation (ref. FFI 2008-02165).

Una mostra de traducció de literatura juvenil: James and the Giant Peach

En aquest Treball Fi de Grau (TFG) farem una anàlisi comparativa de James and the Giant Peach i les seues traduccions al català i al castellà. Pararem especial atenció al fet que es tracta d’un exemple de literatura juvenil, a l’hora d’analitzar els elements típics d’aquest gènere, com ara noms propis, elements culturals, expressions pragmàtiques, etc. El nostre objectiu principal serà extraure unes conclusions ben fonamentades sobre les tendències pel que fa a la traducció de literatura juvenil.