A molecular phylogeny of the African widowbirds and bishops, Euplectes spp. (Aves: Passeridae: Ploceinae)

The elaborate male displays and plumage ornaments in the African widowbirds and bishops (Euplectes spp.) have inspired classic studies on mating systems and sexual selection. In order to study the extreme divergence in ornament design and expression in this group, we present and discuss a well-supported molecular phylogeny of the genus and its placement within the Ploceinae subfamily. Parsimony and Bayesian analyses were performed on 2557bp of mitochondrial DNA (ATP6, Cyt b, ND2 and ND3) and a nuclear intron (G3PDH). All 17 Euplectes species, and 31 of 51 suggested subspecies, were included, as well as eight Ploceinae outgroups from four genera (Amblyospiza, Ploceus, Quelea and Foudia). Our results show monophyly of Euplectes, but not of the intrageneric groupings of bishops and widowbirds. Most notably, the Red-collared Widowbird E. ardens belongs to a subclade of bishops, and not to the sister subclade of 'true' widowbirds. Furthermore, the two bishops E. afer and E. aureus represent lineages that branched off before this basal split, which also refutes the proposed superspecies of E. afer and E. diadematus. Also somewhat surprisingly, and despite the striking plumage similarities among the red bishops, E. franciscanus is not closely related to either E. nigroventris or E. orix (of which it until recently was considered a subspecies). Finally, the Mountain Marsh Widowbird E. psammocromius is likely closest to the Long-tailed Widowbird E. progne, and not, as previously thought, to the Marsh Widowbird E. hartlaubi.     

Photodynamic targeting of EGFR does not predict the treatment outcome in combination with the EGFR tyrosine kinase inhibitor Tyrphostin AG1478

Photodynamic therapy (PDT) is a selective treatment modality against cancer. PDT is based on the preferential retention of photosensitizers (PSs), in the tumour and subsequent light exposure which activates the PS and generates reactive oxygen species. Multimodality therapy is increasingly relevant in cancer treatment and PDT has been shown as an effective adjuvant to other anti-cancer modalities. The present study reports on the combination of PDT and an epidermal growth factor receptor (EGFR) specific tyrosine kinase inhibitor (TKI), Tyrphostin AG1478. The combination was studied in two cell lines; A-431 and NuTu-19, expressing EGFR and sensitive to Tyrphostin treatment, but with different sensitivity towards photochemical EGFR damage. A-431 cells were treated with the PS meso-tetraphenylporphine with 2 sulfonate groups on adjacent phenyl rings (TPPS(2a)) in order to target mainly the endo/lysosomal compartments (18 h incubation followed by a 4 h chase in drug-free medium) or the plasma membrane (30 min incubation) upon light exposure. The EGFR was inhibited after PDT in A-431 cells only when TPPS(2a) was located on the plasma membrane, but both treatment regimes resulted in synergistic inhibition of cell growth when combined with Tyrphostin. TPPS(2a) treatment of NuTu-19 cells, designed for endo/lysosomal localization, followed by light attenuated EGFR phosphorylation but resulted in additive or antagonistic effects on cell growth when Tyrphostin was administered prior to or after PDT respectively. It was therefore concluded that photochemical damage of EGFR does not predict the treatment outcome when PDT is combined with Tyrphostin.     

Crystal structures of barley thioredoxin h isoforms HvTrxh1 and HvTrxh2 reveal features involved in protein recognition and possibly in discriminating the isoform specificity

H-type thioredoxins (Trxs) constitute a particularly large Trx sub-group in higher plants. Here, the crystal structures are determined for the two barley Trx h isoforms, HvTrxh1 and HvTrxh2, in the partially radiation-reduced state to resolutions of 1.7 A, and for HvTrxh2 in the oxidized state to 2.0 A. The two Trxs have a sequence identity of 51% and highly similar fold and active-site architecture. Interestingly, the four independent molecules in the crystals of HvTrxh1 form two relatively large and essentially identical protein-protein interfaces. In each interface, a loop segment of one HvTrxh1 molecule is positioned along a shallow hydrophobic groove at the primary nucleophile Cys40 of another HvTrxh1 molecule. The association mode can serve as a model for the target protein recognition by Trx, as it brings the Met82 Cgamma atom (gamma position as a disulfide sulfur) of the bound loop segment in the proximity of the Cys40 thiol. The interaction involves three characteristic backbone-backbone hydrogen bonds in an antiparallel beta-sheet-like arrangement, similar to the arrangement observed in the structure of an engineered, covalently bound complex between Trx and a substrate protein, as reported by Maeda et al. in an earlier paper. The occurrence of an intermolecular salt bridge between Glu80 of the bound loop segment and Arg101 near the hydrophobic groove suggests that charge complementarity plays a role in the specificity of Trx. In HvTrxh2, isoleucine corresponds to this arginine, which emphasizes the potential for specificity differences between the coexisting barley Trx isoforms.     

Rearranged gene order between pig and human in a QTL region on SSC 7

On porcine Chromosome 7, the region surrounding the MHC region contains QTL influencing many traits including growth, back fat thickness, and carcass composition. Towards the identification of the responsible gene(s), this article describes an increase of density of the radiated hybrid map of SSC 7 in the q11-q14 region and the comparative analysis of gene order on the porcine RH map and human genome assembly. Adding 24 new genes in this region, we were able to build a framework map that fills in gaps on the previous maps. The new software Carthagene was used to build a robust framework in this region. Comparative analysis of human and porcine maps revealed a global conservation of gene order and of distances between genes. A rearranged fragment of around 3.7 Mb was, however, found in the pig approximately 20 Mb upstream from the expected location on the basis of the human map. This rearrangement, found by RH mapping on the IMpRH 7.000 rads panel, has been confirmed by two-color FISH and by mapping on the high resolution IMNpRH2 12.000 rads panel. The rearranged fragment contains two microsatellites found at the most likely QTL location in the INRA QTL experiment. It also contains the BMP5 gene, which, together with CLPS, could be considered as a possible candidate.     

A pyritized lepidocoleid machaeridian (Annelida) from the Lower Devonian Hunsrück Slate,Germany

A machaeridian, Lepidocoleus hohensteini sp. nov., is described from the Hunsrück Slate (Lower Emsian) of Germany. The available material includes a unique example preserving evidence of the soft tissues, only the second machaeridian specimen to do so and the first lepidocoleid. This specimen shows that the plates are attached to alternate segments in the trunk. The morphology is consistent with an annelid affinity of the Lepidocoleidae and confirms the unity of the Machaeridia. This discovery adds an important group to the known diversity of this famous late Palaeozoic marine Konservat-Lagerstätte.     

Nonlinear viscoelastic biomaterials: meaningful characterization and engineering inspiration

Nonlinear mechanical properties play an important role in numerous biological functions, for instance the locomotion strategy used by terrestrial gastropods. We discuss the progress made toward bioinspired snail-like locomotion and the pursuit of an engineered fluid that imitates the nonlinear viscoelastic properties of native gastropod pedal mucus. The rheological behavior of native pedal mucus is characterized using an oscillatory deformation protocol known as large amplitude oscillatory shear, and we review recently developed techniques for appropriately describing nonlinear viscoelastic behavior. Although materials that exhibit purely elastic and purely viscous nonlinearities are amenable to standard techniques for characterization, pedal mucus samples (and biomaterials in general) are viscoelastic, exhibiting both elastic and viscous nonlinear responses simultaneously and requiring advanced techniques for characterization. We reveal the utility of these new methods by examining trail mucus from the terrestrial slug Limax maximus using oscillatory shear rheology. Material responses which previously could only be described mathematically, with little physical insight, can now be interpreted with familiar language such as strain-stiffening/softening and shear-thickening/thinning. The new methodology is applicable to any complex material that can be tested using imposed oscillatory deformations. We have developed data-analysis software to enable wider use of this framework within and beyond the biomaterials community. The functionality of this software is outlined here.