ALBERT

Description: In contrast to the continuous increase in survival rates for many cancer entities, colorectal cancer (CRC) and pancreatic cancer are predicted to be ranked among the top 3 cancer-related deaths in the European Union by 2025. Especially, fighting metastasis still constitutes an obstacle to be overcome in CRC and pancreatic cancer. As described by Fearon and Vogelstein, the development of CRC is based on sequential mutations leading to the activation of proto-oncogenes and the inactivation of tumour suppressor genes. In pancreatic cancer, genetic alterations also attribute to tumour development and progression. Recent findings have identified new potentially important transcription factors in CRC, among those the activating transcription factor 2 (ATF2). ATF2 is a basic leucine zipper protein and is involved in physiological and developmental processes, as well as in tumorigenesis. The mutation burden of ATF2 in CRC and pancreatic cancer is rather negligible; however, previous studies in other tumours indicated that ATF2 expression level and subcellular localisation impact tumour progression and patient prognosis. In a tissue- and stimulus-dependent manner, ATF2 is activated by upstream kinases, dimerises and induces target gene expression. Dependent on its dimerisation partner, ATF2 homodimers or heterodimers bind to cAMP-response elements or activator protein 1 consensus motifs. Pioneering work has been performed in melanoma in which the dual role of ATF2 is best understood. Even though there is increasing interest in ATF2 recently, only little is known about its involvement in CRC and pancreatic cancer. In this review, we summarise the current understanding of the underestimated ‘cancer gene chameleon’ ATF2 in apoptosis, epithelial-to-mesenchymal transition and microRNA regulation and highlight its functions in CRC and pancreatic cancer. We further provide a novel ATF2 3D structure with key phosphorylation sites and an updated overview of all so-far available mouse models to study ATF2 in vivo.

Description: While different microalgae tend to be associated with different bacteria, it remains unclear whether such specific associations are beneficial for the microalgae. We assessed the impact of bacterial isolates, derived from various marine benthic diatoms, on the growth of several strains belonging to the Cylindrotheca closterium diatom species complex. We first tested the effect of 35 different bacterial isolates on the growth of a single C. closterium strain, and then evaluated the impact of 8 of these isolates on the growth of 6 C. closterium strains and 1 Cylindrotheca fusiformis strain. Surprisingly, most interactions were neutral to antagonistic. The interactions were highly specific, with diatom growth in the presence of specific bacteria differing between Cylindrotheca strains and species, and closely related bacteria eliciting contrasting diatom growth responses. These differences could be related to the origin of the bacterial isolates, as only isolates from foreign diatom hosts significantly reduced diatom growth, implying coadaptation between different Cylindrotheca strains and their associated bacteria. Interestingly, the antagonistic effect of a Marinobacter strain was alleviated by the presence of a microbial inoculum that was native to the diatom host, suggesting that coadapted bacteria might also benefit their host indirectly by preventing the establishment of harmful bacteria.

Description: We present a detailed analysis of deep VLT/X-Shooter observations of the planetary nebula Tc 1. We calculate gas temperature, density, extinction, and abundances for several species from the empirical analysis of the total line fluxes. In addition, a spatially resolved analysis of the most intense lines provides the distribution of such quantities across the nebula. The new data reveal that several lines exhibit a double peak spectral profile consistent with the blue and redshifted components of an expanding spherical shell. The study of such components allowed us to construct for the first time a three-dimensional morphological model, which reveals that Tc 1 is a slightly elongated spheroid with an equatorial density enhancement seen almost pole on. A few bright lines present extended wings (with velocities up to a few hundred km s−1), but the mechanism producing them is not clear. We constructed photoionization models for the main shell of Tc 1. The models predict the central star temperature and luminosity, as well as the nebular density and abundances similar to previous studies. Our models indicate that Tc 1 is located at a distance of approximately 2 kpc. We report the first detection of the [Kr iii] 6825 Å emission line, from which we determine the Krypton abundance. Our model indicates that the main shell of Tc 1 is matter bounded; leaking H ionizing photons may explain the ionization of its faint AGB-remnant halo.

Description: The Upper Zone of the Rustenburg Layered Suite of the Bushveld Complex contains the world’s largest Fe–Ti–V ± P deposit and formed from the last major injection of magma into the chamber. Quantitative textural analysis of Upper Zone rocks was undertaken to constrain the processes operating during mush formation and solidification, focussing on horizons with the greatest density contrast to isolate the effects of gravitational loading. We examined three magnetitite layers, together with their underlying and overlying anorthosites. The similarity of microstructures in anorthosites above and below the dense magnetitite layers suggests that the rocks were not affected by viscous compaction driven by gravitational loading. The magnetitite cumulate layers formed by crystal accumulation from a mobile crystal slurry dominated by the Fe-rich conjugate of an unmixed immiscible liquid. We suggest a new mechanism of crystal nucleation in deforming crystal-rich systems, driven by undercooling caused by cavitation as grains slide past each other during simple shear. We propose that the super-solidus deformation recorded in these rocks was caused by prolonged regional subsidence of the magma chamber at Upper Zone times.