Spatial,seasonal and individual variation in the diet of White‐tailed Eagles Haliaeetus albicilla assessed using stable isotope ratios

Many raptor species are considered to be generalists, taking a range of prey species. However, longitudinal dietary records are often scarce, although necessary for characterizing niche width of species at population and individual levels. Quantifying raptor diets at large spatio‐temporal scales is often necessary for refining conservation efforts, although it can be particularly difficult and may involve a great effort by conventional means. Therefore, we adopted the analysis of stable isotopes in tissues of predators and their potential food sources as a complementary methodology for assessing animals' diet. We examined the isotopic composition (δ¹³C and δ¹⁵N) of White‐tailed Eagles Haliaeetus albicilla from Germany, Finland and Greenland to detect patterns of dietary variation and quantify diet composition. The isotopic analysis included liver and muscle samples from Eagles of the three populations together with 16 potential food sources in the German population. Our results suggested dietary differences between German and Greenlandic Eagles, in accordance with the availability of freshwater and marine habitats in each population. Within the German population, we found seasonal shifts in isotopic ratios, suggesting the birds responded to temporal changes in food availabilities, and age‐related isotopic differences, indicating different diets in adults and juveniles. Isotopic values of liver and muscle tissues collected from the same animal showed intra‐individual short‐term changes in the German and Finnish but not Greenlandic population. This suggests that local feeding niches of this generalist predator may vary with local food supplies, which determines the niche width (from generalist to specialist) at the individual level. Our results also revealed that game mammal carcasses constitute an important food source (29.5% of diet) for the German Eagle population during the winter half‐year corresponding to the hunting season. This result is of relevance to management and conservation because the White‐tailed Eagle and other raptor species are affected by the ingestion of lead ammunition from shot mammalian carcasses.     

Global patterns and substrate‐based mechanisms of the terrestrial nitrogen cycle

Nitrogen (N) deposition is impacting the services that ecosystems provide to humanity. However, the mechanisms determining impacts on the N cycle are not fully understood. To explore the mechanistic underpinnings of N impacts on N cycle processes, we reviewed and synthesised recent progress in ecosystem N research through empirical studies, conceptual analysis and model simulations. Experimental and observational studies have revealed that the stimulation of plant N uptake and soil retention generally diminishes as N loading increases, while dissolved and gaseous losses of N occur at low N availability but increase exponentially and become the dominant fate of N at high loading rates. The original N saturation hypothesis emphasises sequential N saturation from plant uptake to soil retention before N losses occur. However, biogeochemical models that simulate simultaneous competition for soil N substrates by multiple processes match the observed patterns of N losses better than models based on sequential competition. To enable better prediction of terrestrial N cycle responses to N loading, we recommend that future research identifies the response functions of different N processes to substrate availability using manipulative experiments, and incorporates the measured N saturation response functions into conceptual, theoretical and quantitative analyses.     

Factors influencing IUCN threat levels to orchids across Europe on the basis of national red lists

The red list has become a ubiquitous tool in the conservation of species. We analyzed contemporary trends in the threat levels of European orchids, in total 166 species characterized in 27 national red lists, in relation to their reproductive biology and growth form, distribution area, and land cover where they occur. We found that species in central Europe are more threatened than those in the northern, southern, or Atlantic parts of Europe, while species were least threatened in southern Europe. Nectarless and tuberous species are significantly more threatened than nectariferous and rhizomatous taxa. Land cover (ratios of artificial land cover, area of pastures and grasslands, forests and inland wetlands) also significantly impacted the threat level. A bigger share of artificial land cover increases threat, and a bigger share of pasture and grassland lowers it. Unexpectedly, a bigger share of inland wetland area in a country increased threat level, which we believe may be due to the threatened nature of wetlands themselves relative to other natural land cover types. Finally, species occurring in multiple countries are on average less threatened. We believe that large‐scale analysis of current IUCN national red lists as based on their specific categories and criteria may particularly inform the development of coordinated regional or larger‐scale management strategies. In this case, we advocate for a coordinated EU protection and restoration strategy particularly aimed at central European orchids and those occurring in wetland area.     

Reversed phase chromatography of isoaccepting tRNA''s from healthy and crown gall tissues from Nicotiana tabacum.

RPC 5 (Reversed Phase Chromatography) of aminoacyl-tRNA's from healthy and crown gall (induced by Agrobacterium tume-faciens strain B6) tobacco tissues were compared for eleven amino acids. For ten amino acids: alanine, arginine, glutamic acid, glycine, isoleucine, leucine, lysine, methionine, tyrosine, and valine, no qualitative or quantitative differences could be detected between aminoacyl-tRNA's from both sources. Phenylalanyl-tRNA's from crown gall tissues gave two peaks on RPC 5; the minor early eluting species (peak 1) was always absent in elution profiles of phenylalanyl-tRNA's from healthy tissues or from tobacco leaves. After the "Y" base was removed by pH 2.9 treatment, peak 2 of phenylalanine tRNA was shifted to the position of peak 1.     

Naturally occurring opioid peptides modulate H+-production by isolated rat parietal cells

The rationale for the present study was to determine the effects of naturally occurring opioid peptides on H+-production by isolated rat parietal cells as indirectly measured by [14C]-aminopyrine uptake. In crude preparations (18 to 25% parietal cells) and in enriched (80 to 90%) parietal cell fractions stimulation by submaximal histamine- or dibutyryl cAMP-concentrations (10(-6)-10(-4) mol/l) was augmented by 20-30% in the presence of methionine-enkephalin (Met-Enk) and Met-Enk Arg6Phe7 (10(-7) to 10(-5) mol/l). This augmentation was blocked by the opiate receptor antagonist (-)naloxone (10(-6) mol/l) suggesting specificity of the action of Met-Enk and Met-Enk Arg6Phe7. At 10(-6) mol/l (-)naloxone did not exert nonspecific toxic effects. Yet, even in the absence of exogenous opioids, histamine-induced H+-production was inhibited by 3 X 10(-5) or 10(-4) mol/l (-)naloxone. Since similar inhibition occurred with (+)naloxone, an inactive stereoisomer which does not interact with opiate receptors, effects of (-)naloxone at concentrations above 10(-5) mol/l must be considered nonspecific. We conclude that Met-Enk and Met-Enk Arg6Phe7 have no effect on basal, but augment stimulated H+-production by a direct effect on the parietal cells. At nontoxic concentrations (-)naloxone antagonizes this augmentation indicating that it is mediated by specific opiate receptors on the parietal cells.     

Immunomodulatory effects of arabinogalactan-proteins from Baptisia and Echinacea

The influences of different arabinogalactan-proteins (AGPs) on proliferation and IgM-production of mouse lymphocytes as well as nitrite- and IL6-production of mouse macrophages were investigated in vitro. AGPs have been isolated and purified from roots of Baptisia tinctoria and Echinacea pallida and suspension culture of Echinacea purpurea. Comparing the AGPs, there are differences with regard to fine structure as well as to activities. AGPs from roots of B. tinctoria and E. pallida show high activity in all test systems. AGP from cell culture of E. purpurea shows no influence on proliferation of mouse lymphocytes, only weak influence on the IgM-production of mouse lymphocytes and weak stimulation of nitrite- and IL6-production in alveolar mouse macrophage culture.     

Optimized prodigiosin production with Pseudomonas putida KT2440 using parallelized noninvasive online monitoring

The red pigment prodigiosin is of high pharmaceutical interest, due to its potential applications as an antitumor drug and antibiotic agent. As previously demonstrated, Pseudomonas putida KT2440 is a suitable host for prodigiosin production, as it exhibits high tolerance toward the antimicrobial properties of prodigiosin. So far, prodigiosin concentrations of up to 94 mg/L have been achieved in shake flask cultivations. For the characterization and optimization of the prodigiosin production process, the scattered light of P. putida and fluorescence of prodigiosin was measured. The excitation and emission wavelengths for prodigiosin measurement were analyzed by recording 2D fluorescence spectra. The strongest prodigiosin fluorescence was obtained at a wavelength combination of 535/560 nm. By reducing the temperature to 18 °C and using 16 g/L glucose, the prodigiosin concentration was more than doubled compared with the initial cultivation conditions. The obtained results demonstrate the capabilities of parallelized microscale cultivations combined with noninvasive online monitoring of fluorescence for rapid bioprocess development, using prodigiosin as a molecule of current biotechnological interest.     

Microbial CO(2) fixation and sulfur cycling associated with low-temperature emissions at the Lilliput hydrothermal field, southern Mid-Atlantic Ridge (9 degrees S)

Lilliput was discovered in 2005 as the southernmost known hydrothermal field along the Mid-Atlantic Ridge. It is exceptional in that it lacks high-temperature venting probably because of a thickened crust. The absence of thermophilic and hyperthermophilic prokaryotes in emissions supports the argument against the presence of a hot subsurface at Lilliput, as is typically suggested for diffuse emissions from areas of high-temperature venting. The high phylogenetic diversity and novelty of bacteria observed could be because of the low-temperature influence, the distinct location of the hydrothermal field or the Bathymodiolus assemblages covering the sites of discharge. The low-temperature fluids at the Lilliput are characterized by lowered pH and slightly elevated hydrogen (16 nM) and methane ( approximately 2.6 microM) contents compared with ambient seawater. No typical hydrogen and methane oxidizing prokaryotes were detected. The higher diversity of reverse tricarboxylic acid genes and the form II RubisCO genes of the Calvin Benson-Bassham (CBB) cycle compared with the form I RubisCO genes of the CBB cycle suggests that the chemoautotrophic community is better adapted to low oxygen concentrations. Thiomicrospira spp. and Epsilonproteobacteria dominated the autotrophic community. Sulfide is the most abundant inorganic energy source (0.5 mM). Diverse bacteria were associated with sulfur cycling, including Gamma-, Delta- and Epsilonproteobacteria, with the latter being the most abundant bacteria according to fluorescence in situ hybridization. With members of various Candidate Divisions constituting for 25% of clone library sequences we suggest that their role in vent ecosystems might be more important than previously assumed and propose potential mechanisms they might be involved in at the Lilliput hydrothermal field.     

Modulation of the Pyrococcus abyssi NucS endonuclease activity by replication clamp at functional and structural levels

Pyrococcus abyssi NucS is the founding member of a new family of structure-specific DNA endonucleases that interact with the replication clamp proliferating cell nuclear antigen (PCNA). Using a combination of small angle x-ray scattering and surface plasmon resonance analyses, we demonstrate the formation of a stable complex in solution, in which one molecule of the PabNucS homodimer binds to the outside surface of the PabPCNA homotrimer. Using fluorescent labels, PCNA is shown to increase the binding affinity of NucS toward single-strand/double-strand junctions on 5' and 3' flaps, as well as to modulate the cleavage specificity on the branched DNA structures. Our results indicate that the presence of a single major contact between the PabNucS and PabPCNA proteins, together with the complex-induced DNA bending, facilitate conformational flexibility required for specific cleavage at the single-strand/double-strand DNA junction.