Dynamics of leaf-and root-specific biomarkers during 1-year of litter decomposition

Root-specific and leaf-specific biomarkers have been used for decades to identify the origin of organic materials in soils and sediments. However, quantitative approaches require appropriate knowledge about the fate of these indicator molecules during degradation. To clarify this issue, we performed a 1-year incubation experiment with fine root and leaf material of six temperate tree species: European ash (Fraxinus excelsior), European beech (Fagus sylvatica), Oak spec. (Quercus spec.), Linden spec. (Tilia spec.), Norway spruce (Picea abies) and Scots pine (Pinus sylvatica). Only one molecule, x,16-dihydroxy hexadecanoic acid (x,16-C16), could be validated as a general leaf-specific biomarker for the set of all species. For roots, no general root biomarker was found. Ester-bound tricosanol (C23-OH) could be validated for five out of six species; 20-hydroxy eicosanoic acid (ωC20) could be validated for four out of six species, leaving Norway spruce without a suitable root biomarker. The results of this study suggest that the validity of leaf- and root-derived ester-bound lipids as biomarkers is highly species dependent and does not always coincide with previous findings. Concentrations of root- and leaf-derived ester-bound lipids did not stay constant within 1 year of degradation and changed without a linear trend. The change of concentrations seems to be highly species dependent. This might be due to a different structure and arrangement of the individual monomers in cutin and suberin per species, and, therefore, a different accessibility of bond cleaving enzymes. The usefulness of root and leaf biomarkers is context dependent. Our results suggest that general assumptions about litter input to forest soils solely based on biomarker analysis have to be considered carefully

Application of the radio-iodine rose bengal test in liver disease in infancy and childhood

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Collison effects in the nonlinear Raman response of liquid carbon disulfide

The contributions of induced-multipole and electron overlap effects to the third-order Raman response were studied. A model was constructed on the polarizability of carbon disulfide dimers using polarizabilities from accurate time-dependent density functional theory calculations. The model was used to calculate the third-order time-domain Raman response of liquid carbon disulfide

Assessment of heavy metals concentration in water, soil sediment and biological tissues of the lesser flamingos in four eastern rift valley lakes

The term heavy metal refers to any metallic chemical element that has a relatively high density and is toxic at low concentrations. This study was conducted in four eastern Rift Valley lakes which included Lakes Oloidien, Crater, Elementaita and Nakuru, to determine the presence and levels of lead, arsenic, cadmium and chromium concentration in water, soil sediments and biological tissues of the Lesser Flamingos (Phoeniconaias minor) and compare with the set standards. As these lakes catchments fall directly within a combination of agricultural and industrial regions, the run-offs and the resulting effluents will make the waters highly prone to chemical contamination. The methodology involved collection of water samples (n=40), sediments samples (n=51) and the Lesser Flamingos (live n= 6; dead n=2) for qualitative and quantitative toxicological analysis. The analysis was done using Graphite Furnace Atomic Absorption Spectrophotometer (GFAAS) model-Specter AA-10 Varian. Lead and arsenic were found to be in high concentration in soil sediments in all four lakes while chromium and cadmium were in low concentration. Soil sediments analysed from the inflow of the Nakuru sewerage drain (1754±22.81 ppb) and rivers to Lake Nakuru (1129±107 ppb) had the highest mean ± SD lead concentration. Arsenic, cadmium, chromium and lead were also observed in bird tissues. Metals in the Lesser Flamingo tissues were below the toxicological levels that are reported in literature to be harmful, except lead which was above the level recommended by the US Environmental Protection Agency.Keywords: Heavy metals, lesser flamingo, environmen

Mesheften (Ensis directus), Strandschelpen (Spisula subtruncata), Kokkels (Cerastoderma edule), Mosselen (Mytilus edulis) en Otterschelpen (Lutraria lutraria) in de Nederlandse kustwateren in 2009

Het doel van deze inventarisaties is het in kaart brengen van de bestanden van commercieel interessante soorten en het weergeven van de fluctuaties in de tijd, ten behoeve van het visserijbeleid. Het onderzoek is in eerste instantie gericht op de Amerikaanse zwaardschede (mesheften) (Ensis directus), de halfgeknotte strandschelp (Spisula subtruncata) en de kokkel (Cerastoderma edule). Daarnaast bleek er een voortgezette toename van een voorheen minder algemene soort, de gewone otterschelp (Lutraria lutraria), tot een niveau dat commerciële exploitatie wellicht mogelijk maakt. In dat perspectief is de otterschelp in de berekening van de bestanden meegenomen

DNA mismatch repair-dependent DNA damage responses and cancer

Canonical DNA mismatch repair (MMR) excises base-base mismatches to increase the fidelity of DNA replication. Thus, loss of MMR leads to increased spontaneous mutagenesis. MMR genes also are involved in the suppression of mutagenic, and the induction of protective, responses to various types of DNA damage. In this review we describe these non-canonical roles of MMR at different lesion types. Loss of non-canonical MMR gene functions may have important ramifications for the prevention, development and treatment of colorectal cancer associated with inherited MMR gene defects in Lynch syndrome. This graphical review pays tribute to Samuel H. Wilson. Sam not only made seminal contributions to understanding base excision repair, particularly with respect to structure-function relationships in DNA polymerase beta but also, as Editor of DNA Repair, has maintained a high standard of the journal.Genome Instability and Cance

A pesca e o conhecimento ecológico local dos pescadores de acará-disco (Symphysodon aequifasciatus, Pellegrin 1904: Cichlidae) na Reserva de Desenvolvimento Sustentável Piagaçu-Purus, baixo rio Purus, Brasil

The discus fish (Symphysodon aequifasciatus, Pellegrin 1904), an endemic cichlid from the Amazon basin, is one of the most popular ornamental fish species in the world. However, there is little information available in the scientific literature on the exploitation of this species in its natural habitat. In this article we describe the small-scale discus fisheries activity in the Reserva de Desenvolvimento Sustentável Piagaçu-Purus (RDS-PP), lower Purus River, Brazil, based on field observations, structured and open-ended interviews with fishermen and local inhabitants. Discus fishery is seasonal, occurring mainly in the dry season. Local fishermen use fish attractors to catch the species and underwater hearing methods to estimate its presence and abundance. Discus fishes are locally kept in wooden storage tanks and carried in plastic containers for distribution in regional markets by means of fishing boats, commercial boat lines or rafts. Discuses are sold in Manaus, State of Amazonas, to export companies specialized in ornamental fish trade. We describe the local ecological knowledge on the discus among fishermen living within the RDS-PP and discuss its importance for ornamental fishery management in that protected area

Exact results for the reactivity of a single-file system

We derive analytical expressions for the reactivity of a Single-File System with fast diffusion and adsorption and desorption at one end. If the conversion reaction is fast, then the reactivity depends only very weakly on the system size, and the conversion is about 100%. If the reaction is slow, then the reactivity becomes proportional to the system size, the loading, and the reaction rate constant. If the system size increases the reactivity goes to the geometric mean of the reaction rate constant and the rate of adsorption and desorption. For large systems the number of nonconverted particles decreases exponentially with distance from the adsorption/desorption end.Comment: 4 pages, 2 figure