Subalpine grassland carbon dioxide fluxes indicate substantial carbon losses under increased nitrogen deposition,but not at elevated ozone concentration

Ozone (O₃) and nitrogen (N) deposition affect plant carbon (C) dynamics and may change ecosystem C‐sink/‐source properties. We studied effects of increased background [O₃] (up to [ambient] × 2) and increased N deposition (up to +50 kg ha^?1 a^?1) on mature, subalpine grassland during the third treatment year. During 10 days and 13 nights, distributed evenly over the growth period of 2006, we measured ecosystem‐level CO₂ exchange using a static cuvette. Light dependency of gross primary production (GPP) and temperature dependency of ecosystem respiration rates (R_eco) were established. Soil temperature, soil water content, and solar radiation were monitored. Using R_eco and GPP values, we calculated seasonal net ecosystem production (NEP), based on hourly averages of global radiation and soil temperature. Differences in NEP were compared with differences in soil organic C after 5 years of treatment. The high [O₃] had no effect on aboveground dry matter productivity (DM), but seasonal mean rates of both R_eco and GPP decreased ca. 8%. NEP indicated an unaltered growing season CO₂–C balance. High N treatment, with a +31% increase in DM, mean R_eco increased ca. 3%, but GPP decreased ca. 4%. Consequently, seasonal NEP yielded a 53.9 g C m^?2 (±22.05) C loss compared with control. Independent of treatment, we observed a negative NEP of 146.4 g C m^?2 (±15.3). Carbon loss was likely due to a transient management effect, equivalent to a shift from pasture to hay meadow and a drought effect, specific to the 2006 summer climate. We argue that this resulted from strongly intensified soil microbial respiration, following mitigation of nutrient limitation. There was no interaction between O₃ and N treatments. Thus, during the 2006 growing season, the subalpine grassland lost >2% of total topsoil organic C as respired CO₂, with increased N deposition responsible for one‐third of that loss.     

The innate immune receptor MDA5 limits rotavirus infection but promotes cell death and pancreatic inflammation

Melanoma differentiation‐associated protein 5 (MDA5) mediates the innate immune response to viral infection. Polymorphisms in IFIH1, the gene coding for MDA5, correlate with the risk of developing type 1 diabetes (T1D). Here, we demonstrate that MDA5 is crucial for the immune response to enteric rotavirus infection, a proposed etiological agent for T1D. MDA5 variants encoded by minor IFIH1 alleles associated with lower T1D risk exhibit reduced activity against rotavirus infection. We find that MDA5 activity limits rotavirus infection not only through the induction of antiviral interferons and pro‐inflammatory cytokines, but also by promoting cell death. Importantly, this MDA5‐dependent antiviral response is specific to the pancreas of rotavirus‐infected mice, similar to the autoimmunity associated with T1D. These findings imply that MDA5‐induced cell death and inflammation in the pancreas facilitate progression to autoimmune destruction of pancreatic β‐cells.     

Bi-directional soil/atmosphere N2O exchange over two mown grassland systems with contrasting management practices

Nitrous oxide (N₂O) fluxes from soil under mown grassland were monitored using static chambers over three growing seasons in intensively and extensively managed systems in Central Switzerland. Emissions were largest following the application of mineral (NH₄NO₃) fertilizer, but there were also substantial emissions following cattle slurry application, after grass cuts and during the thawing of frozen soil. Continuous flux sampling, using automatic chambers, showed marked diurnal patterns in N₂O fluxes during emission peaks, with highest values in the afternoon. Net uptake fluxes of N₂O and subambient N₂O concentrations in soil open pore space were frequently measured on both fields. Flux integration over 2.5 years yields a cumulated emission of +4.7 kgN₂O‐N ha^?1 for the intensively managed field, equivalent to an average emission factor of 1.1%, and a small net sink activity of ?0.4 kg N₂O‐N ha^?1 for the unfertilized system. The data suggest the existence of a consumption mechanism for N₂O in dry, areated soil conditions, which cannot be explained by conventional anaerobic denitrification. The effect of fertilization on greenhouse gas budgets of grassland at the ecosystem level is discussed.     

Effect of NSAIDs and Diuretics on Nephrogenesis in an Ex Vivo Embryogenic Kidney Model

The kidney is one of the key organs in clearing foreign compounds. The effects of drugs on the developing kidney are relatively unknown. We studied the direct effect of furosemide, hydrochlorothiazide, ibuprofen, and indomethacin on kidney development in an ex vivo embryonic kidney model. At embryonic day 13, metanephroi were dissected from mice and cultured in control media or media supplemented with various clinically relevant concentrations of drugs. The ureteric tree was visualized by whole‐mount staining and branching was evaluated by counting. Additionally, gene expression levels of Wt1, Sox9, Bmp7, Fgf8, and Gdnf were investigated. No distinct differences were noted on either ureteric tip development or gene expression analysis for each drug after 24 hr of exposure. Even though short‐term exposure to clinically relevant concentrations seems not to disturb renal development, future research is needed to study prolonged or repeated exposures.     

Nine new polymorphic microsatellite loci for the amplification of archived otolith DNA of Atlantic cod,Gadus morhua L.

Nine out of 22 microsatellite primers tested were successfully amplified on three samples of cod Gadus morhua L. (two contemporary and one archived otolith samples). All loci were polymorphic (5–23 alleles/locus). The average observed heterozygosity across loci and samples was 0.625, ranging from 0.294 to 0.895 at each locus. All loci were under Hardy–Weinberg equilibrium, except PGmo56 that showed significant excess of heterozygotes in all studied samples. The isolated loci were suitable for degraded DNA and therefore useful for conducting a long‐term temporal study with DNA obtained from archived otoliths of cod.     

ISOLATED GRAPTOLITES FROM THE LITUIGRAPTUS CONVOLUTUS BIOZONE (SILURIAN, LLANDOVERY) OF DALARNA, SWEDEN

Abstract:  Isolated material of 13 graptolite species from the Aeronian (middle Llandovery) Lituigraptus convolutus Biozone is described. A considerable amount of late astogenetic peridermal thickening is revealed in Normalograptus scalaris and Rivagraptus bellulus . As a result, in the former, thecal morphology is modified from climacograptid to pseudoglyptograptid; in both species, the virgella becomes robust. In Metaclimacograptus minimus and Me. sp., it is shown that the dorsal metathecal wall forms the genicular hood, whereas in N. nikolayevi , the infragenicular wall of the succeeding theca forms the distal thecal apertural margin. Pribylograptus argutus exhibits typical pribylograptid thecae along the length of the available rhabdosome fragments. Characters differentiating Campograptus lobiferus from C. harpago include the greater dorso-ventral width and more rapid increase in dorso-ventral width of the former and the greater recurving of distal thecae and presence of thecal spines/processes on all thecae of the latter. Lituigraptus convolutus has rastritiform thecae proximally; thecal apertures throughout the rhabdosome are crescentic and laterally expanded.     

Soil Consumption of Two Groups of Semi-free-ranging Lemurs {Lemur catta and Lemur fulvus)

Soil consumption of two Malagasy lemurs, Lemur catta and Lemur fulvus was observed in an enclosure simulating a natural habitat at Duke University Primate Center (Durham, USA). Soil eaten by L. catta contained more Na than random soil samples. Concentrations of the four major minerals in soil eaten by L. fulvus did not differ from random samples. L. fulvus stopped soil ingestion in summer when they ate large amounts of foliage rich in K and Mg, also in winters after being fed with MgCl₂. It is suggested that, in this study, soil was consumed in relation to its mineral content and not for physical properties related to its structure. Some non physiological factors that might influence food selection are discussed.