Multiple roles for protein kinase C in gastropod embryogenesis

Protein kinase C (PKC) contributes to the correct development of organisms, but its importance to the embryogenesis of molluscs is not yet known. We report here that PKC activation is cyclic within early developing embryos of the gastropod snail Lymnaea stagnalis, and that activation with phorbol myristate acetate (PMA) results in disorganised and developmentally arrested embryos within 24 h. Moreover, chronic modulation of PKC activation by PMA or by the PKC inhibitor GF109203X in early embryos results in altered rotation and gliding behaviours and heartbeat during development. Finally, dis-regulation of PKC activity during early development significantly increased the duration to hatching. Our findings thus support novel roles for PKC in L. stagnalis embryos, in several physiological contexts, providing further insights into the importance of protein kinases for gastropod development in general

Extension rates across the northern Shanxi Grabens, China, from Quaternary geology, seismicity and geodesy

Discrepancies between geological, seismic and geodetic rates of strain can indicate that rates of crustal deformation, and hence seismic hazard, are varying through time. Previous studies in the northern Shanxi Grabens, at the northeastern corner of the Ordos Plateau in northern China, have found extension rates of anywhere between 0 and 6 mm a−1 at an azimuth of between 95° and 180°. In this paper we determine extension rates across the northern Shanxi Grabens from offset geomorphological features and a variety of Quaternary dating techniques (including new IRSL and Ar-Ar ages), a Kostrov summation using a 700 yr catalogue of historical earthquakes, and recent campaign GPS measurements. We observe good agreement between Quaternary, seismic and geodetic rates of strain, and we find that the northern Shanxi Grabens are extending at around 1–2 mm a−1 at an azimuth of ≈151°. The azimuth of extension is particularly well constrained and can be reliably inferred from catalogues of small earthquakes. We do not find evidence for any substantial variations in extension rate through time, though there is a notable seismic moment rate deficit since 1750. This deficit could indicate complex fault interactions across large regions, aseismic accommodation of deformation, or that we are quite late in the earthquake cycle with the potential for larger earthquakes in the relatively near future

Medication adherence in patients with myotonic dystrophy and facioscapulohumeral muscular dystrophy

Myotonic dystrophy (DM) and facioscapulohumeral muscular dystrophy (FSHD) are the two most common adult muscular dystrophies and have progressive and often disabling manifestations. Higher levels of medication adherence lead to better health outcomes, especially important to patients with DM and FSHD because of their multisystem manifestations and complexity of care. However, medication adherence has not previously been studied in a large cohort of DM type 1 (DM1), DM type 2 (DM2), and FSHD patients. The purpose of our study was to survey medication adherence and disease manifestations in patients enrolled in the NIH-supported National DM and FSHD Registry. The study was completed by 110 DM1, 49 DM2, and 193 FSHD patients. Notable comorbidities were hypertension in FSHD (44 %) and DM2 (37 %), gastroesophageal reflux disease in DM1 (24 %) and DM2 (31 %) and arrhythmias (29 %) and thyroid disease (20 %) in DM1. Each group reported high levels of adherence based on regimen complexity, medication costs, health literacy, side effect profile, and their beliefs about treatment. Only dysphagia in DM1 was reported to significantly impact medication adherence. Approximately 35 % of study patients reported polypharmacy (taking 6 or more medications). Of the patients with polypharmacy, the DM1 cohort was significantly younger (mean 55.0 years) compared to DM2 (59.0 years) and FSHD (63.2 years), and had shorter disease duration (mean 26 years) compared to FSHD (26.8 years) and DM2 (34.8 years). Future research is needed to assess techniques to ease pill swallowing in DM1 and to monitor polypharmacy and potential drug interactions in DM and FSHD

Regulation of phytoplankton communities by physical processes in upwelling ecosystems

Sinking rates of particles were superimposed on the x-z-t current field observed at 15S off the coast of San Juan, Peru in March–May, 1977 to calculate particle trajectories in the upwelling circulation. Vertical velocities were calculated by a modified variational objective analysis technique using the measured onshore and longshore currents in conjunction with the physical constraint of mass continuity. The calculated vertical flow showed considerable temporal and spatial variability, with the mean vertical transport varying by two orders of magnitude over the 16 km wide continental shelf. Changes in direction occurred rapidly (within 24 h) as has been observed for horizontal circulation in this region. The vertical velocity of water was much greater than the sinking rates of particles during the 52 day period, so that the net vertical transport of particles was controlled by the vertical velocity of the water. Reseeding of sinking particles from the surface offshore-flowing layer into the deeper onshore flow could not be demonstrated for this period, which may explain why the measured biomass and primary productivity were anomalously low in 1977. Vertical mixing greatly increased the possibility of reseeding by transporting material downward into the onshore flow. We suggest that recirculation of particles may normally occur in the Peruvian upwelling system, but that the continuity probably involves movement in the longshore as well as the cross-shelf direction

Exogenous GDF11, but not GDF8, reduces body weight and improves glucose homeostasis in mice

Insulin resistance is associated with aging in mice and humans. We have previously shown that administration of recombinant GDF11 (rGDF11) to aged mice alters aging phenotypes in the brain, skeletal muscle, and heart. While the closely related protein GDF8 has a role in metabolism, limited data are available on the potential metabolic effects of GDF11 or GDF8 in aging. To determine the metabolic effects of these two ligands, we administered rGDF11 or rGDF8 protein to young or aged mice fed a standard chow diet, short-term high-fat diet (HFD), or long-term HFD. Under nearly all of these diet conditions, administration of exogenous rGDF11 reduced body weight by 3-17% and significantly improved glucose tolerance in aged mice fed a chow (~30% vs. saline) or HF (~50% vs. saline) diet and young mice fed a HFD (~30%). On the other hand, exogenous rGDF8 showed signifcantly lesser effect or no effect at all on glucose tolerance compared to rGDF11, consistent with data demonstrating that GFD11 is a more potent signaling ligand than GDF8. Collectively, our results show that administration of exogenous rGDF11, but not rGDF8, can reduce diet-induced weight gain and improve metabolic homeostasis

Ice-Shelf Flexure and Tidal Forcing of Bindschadler Ice Stream, West Antarctica

Viscoelastic models of ice-shelf flexure and ice-stream velocity perturbations are combined into a single efficient flowline model to study tidal forcing of grounded ice. The magnitude and timing of icestream response to tidally driven changes in hydrostatic pressure and/or basal drag are found to depend significantly on bed rheology, with only a perfectly plastic bed allowing instantaneous velocity response at the grounding line. The model can reasonably reproduce GPS observations near the grounding zone of Bindschadler Ice Stream (formerly Ice Stream D) on semidiurnal time scales; however, other forcings such as tidally driven ice-shelf slope transverse to the flowline and flexurally driven till deformation must also be considered if diurnal motion is to be matche

Identification of a major causative agent of human cercarial dermatitis, Trichobilharzia franki (Muller and Kimmig 1994), in southern England and its evolutionary relationships with other European populations.

Background Trichobilharzia is the most species rich and widely distributed genus of schistosomes and is known throughout Europe and North America as an agent of human cercarial dermatitis. The disease is caused by an acute allergic reaction in the skin that develops as a consequence of repeated contact with water containing schistosomatid cercariae. However, despite historical outbreaks of the disease, there are no published records of accurately identified Trichobilharzia species from the UK. Methods Two hundred Radix auricularia (L.) were sampled from a recreational fishing lake in Hampshire and emerging schistosomatid cercariae were collected for microscopy and DNA extraction. General morphological description of the cercariae was performed, alongside sequencing and phylogenetic analysis of the 28S ribosomal DNA for accurate species identification as well as comparisons of ITS1 in order to identify evolutionary affinities with other European populations. All molecular comparisons were performed using published sequences. Results The phylogenetic analysis of 28S sequences identified the cercariae as Trichobilharzia franki. Two unique British ITS1 haplotypes were identified which were most closely related to haplotypes of T. franki populations from France. Haplotype network analysis indicated the mixing of T. franki populations throughout Europe. It is suggested that parasite distribution is the probable result of the movement of migratory waterfowl. Conclusions This is the first accurate record of T. franki in the UK. The movement of T. franki with waterfowl could pose a considerable human health risk, as in mainland Europe, and signifies T. franki-associated human cercarial dermatitis as a re-emerging disease in the UK