The Discovery of a Normative Theory of Justice in Medieval Philosophy: On the Reception and Further Development of Aristotle's Theory of Justice by St. Thomas Aquinas

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MicroRNA preparations from individual monogenean Gyrodactylus salaris-a comparison of six commercially available totalRNA extraction kits

<p>Abstract</p> <p>Background</p> <p>Describing and evaluating miRNA inventories with Next Generation Sequencing is a goal of scientists from a wide range of fields. It requires high purity, high quality, and high yield RNA extractions that do not only contain abundant ribosomal RNAs but are also enriched in miRNAs. Here we compare 6 disparate and commercially available totalRNA extraction kits for their suitability for miRNA-preparations from <it>Gyrodactylus salaris</it>, an important but small (500 μm in length) monogenean pathogen of Norwegian Atlantic salmon (<it>Salmo salar</it>).</p> <p>Findings</p> <p>We evaluated 1 salt precipitation method (MasterPure™ Complete RNA Purification Kit, Epicentre), 2 Phenol based extraction methods (mirVana Kit, Ambion, and Trizol Plus Kit, Invitrogen), 1 paramagnetic bead extraction method (RNA Tissue kit, GeneMole) and 2 purification methods based on spin column chromatography using a proprietary resin as separation matrix (Phenol-free Total RNA Purification Kit, Amresco, and ZR MicroPrep Kit, Zymo Research). The quality of the extractions from 1, 10 and 100 individuals, respectively, was assessed in terms of totalRNA yield, RNA integrity, and smallRNA and miRNA yield. The 6 RNA extraction methods yielded considerably different total RNA extracts, with striking differences in low molecular weight RNA yield. The Phenol-free Total RNA Purification Kit (Amresco) showed the highest totalRNA yield, but the best miRNA/totalRNA ratio was obtained with the ZR MicroPrep Kit (Zymo Research). It was not possible to extract electrophoretically detectable miRNAs from <it>Gyrodactylus salaris </it>with the RNA Tissue Kit (GeneMole) or the Trizol Plus Kit (Invitrogen).</p> <p>Conclusions</p> <p>We present an optimized extraction protocol for single and small numbers of <it>Gyrodactylus salaris </it>from infected Atlantic salmon that delivers a totalRNA yield suitable for downstream next generation sequencing analyses of miRNA. Two of the six tested totalRNA kits/methods were not suitable for the extraction of miRNAs from <it>Gyrodactylus salaris</it>.</p

Effects of BPA in snails : Oehlmann et al. respond

We welcome critical appraisals that help to provide balance; however, Dietrich et al. gave an unjustified reproach. We feel that Dietrich’s position is severely compromised because he serves as an expert for the bisphenol A (BPA) Industry Group (Brussels, Belgium). We would like to respond to the issues raised by Dietrich et al., as well as to their oversights and inappropriate interpretations of our findings..

Bisphenol A induces superfeminization in the Ramshorn snail Marisa cornuarietis (Gastropoda: Prosobranchia) at environmentally relevant concentrations

Previous investigations have shown that bisphenol A (BPA) induces a superfeminization syndrome in the freshwater snail Marisa cornuarietis at concentrations as low as 1 &#956;g/L. Superfemales are characterized by the formation of additional female organs, enlarged accessory sex glands, gross malformations of the pallial oviduct, and a stimulation of egg and clutch production, resulting in increased female mortality. However, these studies were challenged on the basis of incomplete experimentation. Therefore, the objective of the current approach was to bridge several gaps in knowledge by conducting additional experiments. In an initial series of experiments, study results from the reproductive phase of the snails were evaluated in the sub-micrograms per liter range. Before and after the spawning season, superfemale responses were observed [NOEC (no observed effect concentration) 7.9 ng/L, EC10 (effective concentration at 10%) 13.9 ng/L], which were absent during the spawning season. A further experiment investigated the temperature dependence of BPA responses by exposing snails at two temperatures in parallel. The adverse effect of BPA was at least partially masked at 27°C (EC10 998 ng/L) when compared with 20°C (EC10 14.8 ng/L). In M. cornuarietis, BPA acts as an estrogen receptor (ER) agonist, because effects were completely antagonized by a co-exposure to tamoxifen and Faslodex. Antiandrogenic effects of BPA, such as a significant decrease in penis length at 20°C, were also observed. Competitive receptor displacement experiments indicate the presence of androgen- and estrogen-specific binding sites. The affinity for BPA of the estrogen binding sites in M. cornuarietis is higher than that of the ER in aquatic vertebrates. The results emphasize that prosobranchs are affected by BPA at lower concentrations than are other wildlife groups, and the findings also highlight the importance of exposure conditions

La idea de los derechos humanos de cara a las realidades de la política mundial: una reflexión sobre la relación entre ética y política

Me interesa, primero, probar que la relación entre ética y política -en las contribuciones hasta ahora dominantes a la filosofía política de las relaciones internacionales- es insatisfactoria por diferentes razones y exige una nueva concepción (1). En segundo lugar, quisiera hacer la propuesta de una nueva fundamentación de la relación entre ética y política con el transfondo de las nuevas realidades de la política mundial (11). Me interesa, por último, determinar más detalladamente ese transfondo en relación con sus implicaciones para la cuestión acerca de la situación de los derechos humanos

Phylogenetic footprinting of non-coding RNA: hammerhead ribozyme sequences in a satellite DNA family of Dolichopoda cave crickets (Orthoptera, Rhaphidophoridae)

<p>Abstract</p> <p>Background</p> <p>The great variety in sequence, length, complexity, and abundance of satellite DNA has made it difficult to ascribe any function to this genome component. Recent studies have shown that satellite DNA can be transcribed and be involved in regulation of chromatin structure and gene expression. Some satellite DNAs, such as the <it>pDo500 </it>sequence family in <it>Dolichopoda </it>cave crickets, have a catalytic hammerhead (HH) ribozyme structure and activity embedded within each repeat.</p> <p>Results</p> <p>We assessed the phylogenetic footprints of the HH ribozyme within the <it>pDo500 </it>sequences from 38 different populations representing 12 species of <it>Dolichopoda</it>. The HH region was significantly more conserved than the non-hammerhead (NHH) region of the <it>pDo500 </it>repeat. In addition, stems were more conserved than loops. In stems, several compensatory mutations were detected that maintain base pairing. The core region of the HH ribozyme was affected by very few nucleotide substitutions and the cleavage position was altered only once among 198 sequences. RNA folding of the HH sequences revealed that a potentially active HH ribozyme can be found in most of the <it>Dolichopoda </it>populations and species.</p> <p>Conclusions</p> <p>The phylogenetic footprints suggest that the HH region of the <it>pDo500 </it>sequence family is selected for function in <it>Dolichopoda </it>cave crickets. However, the functional role of HH ribozymes in eukaryotic organisms is unclear. The possible functions have been related to <it>trans </it>cleavage of an RNA target by a ribonucleoprotein and regulation of gene expression. Whether the HH ribozyme in <it>Dolichopoda </it>is involved in similar functions remains to be investigated. Future studies need to demonstrate how the observed nucleotide changes and evolutionary constraint have affected the catalytic efficiency of the hammerhead.</p