Activity of nematodes and enchytraeids, bacterial community composition, and functional redundancy in coniferous forest soil

Soil faunal activity stimulates terrestrial carbon and nutrient cycling and maintains soil physical structure. Interestingly, the effects of faunal activity on soil microbial community composition and activity is less clear, although the microbial community evidently is the key element of terrestrial decomposition processes and nutrient cycling. We manipulated the composition of soil fauna in mesh bags with various mesh sizes (5, 45, and 1,000 µm) to exclude faunal groups based on body size. Our experiment indicated that feeding and foraging activity of nematodes and enchytraeids modified the physical–chemical properties of the soil and had long-term effects on soil bacterial community composition (measured by denaturing gel electrophoresis, colony-forming unit counts, and phospholipid fatty acid pattern). However, microbial enzyme (phosphomonoesterase, butyrate-esterase, ß-glucosidase, N-acetyl-glucosamidase, and ß-cellobiosidase) activities (measured by fluorogenic model substrates), decomposition rate of woody and cellulose material, or C and N status of the soil were not altered by the faunal treatment. Instead, enzyme activity was reduced by soil drying. Our results give support to ideas that functional redundancy is a common characteristic of the soil organisms, but no support was found for the idea that the community composition of soil decomposers had a strong link to the regulation of C and N cycles in the soil.     

Comparison of parasite-specific immunoglobulin levels in two chicken lines during sustained infection with Ascaridia galli

Increasingly large numbers of poultry are held in production systems with access to outdoor areas. In these systems intestinal helminths are found with flock prevalences of up to 100%. Helminth infections influence chicken health negatively, which is why the following investigation has been performed.In the present experiment, 20 chickens of two inbred chicken lines containing the major histocompatibility complex (MHC) haplotypes, B14 and R5, were inoculated with 500 embryonated Ascaridia galli eggs. The A. galli-specific IgG titres of serum samples and the excretion of A. galli eggs in chicken faeces were measured for a period of 81 weeks.The level of excreted A. galli eggs measured as eggs per gram chicken faeces (EPG) varied greatly between chickens in each line. Significant differences were found between the two lines and with the R5 chickens reaching the highest levels. Likewise, the A. galli-specific IgG titres in serum differed significantly between the two lines, and an inverse relationship between infection level (EPG) and antibody titres was found. Although this inverse relationship suggests that humoral immunity may be involved in protection against A. galli infection, the high antibody titres did not prevent continued infection.     

Long-term effects of fertilisation regime on earthworm abundance in a semi-natural grassland area

Environmental protection organisations involved in farmland-bird conservation promote the use of organic fertilisers, especially farmyard manure, to enhance the availability of earthworms, which are an important prey for farmland-birds. We studied changes in earthworm numbers in a field experiment on a semi-natural grassland with three different types of fertilisation; no fertilisation (NF), and application of slurry manure (SM) or farmyard manure (FM). Samples were taken in April, yearly from 1982 to 1990 and in 2005. On average, the SM treatment had a lower (29%) earthworm abundance and a higher mean individual body weight than the FM and NF treatments. No statistically significant differences were observed between the FM and NF treatment. In 2005, earthworm abundance did not differ between the SM and NF treatment. The yearly variation in earthworm numbers and biomass was high, and significantly related to winter coldness. Colder winters resulted in lower earthworm abundances in the next spring. Especially the number of endogeic earthworms varied with winter coldness. The large variation between years stresses the need to be careful with the interpretation of short-term field experiments, or comparisons between areas based on single sampling events.     

Templating organic semiconductors via self-assembly of polymer colloids

A route for producing semiconducting polymer blends is demonstrated in which a doped pi-conjugated polymer is forced into a three-dimensionally continuous minor phase by the self-assembly of colloidal particles and block copolymers. The resulting cellular morphology can be viewed as a high-internal phase polymeric emulsion. Compared with traditional blending procedures, this process reduces the percolation threshold for electrical conductivity by a factor of 10, increases the conductivity by several orders of magnitude, and simultaneously improves thermal stability. Following this route, new applications can be envisaged for semiconducting polymer blends that require only minimal concentrations of doped pi-conjugated polymer.     

Natural Removal of Crude and Heavy Fuel Oil on Rocky Shorelines in Arctic Climate Regimes

Water, Air, &; Soil Pollution - The ecotoxicity of nickel depends on water quality characteristics such as pH and dissolved organic carbon. Bioavailability models to predict nickel toxicity have...     

Accurate and reproducible determination of lignin molar mass by acetobromination

The accurate and reproducible determination of lignin molar mass by using size exclusion chromatography (SEC) is challenging. The lignin association effects, known to dominate underivatized lignins, have been thoroughly addressed by reaction with acetyl bromide in an excess of glacial acetic acid. The combination of a concerted acetylation with the introduction of bromine within the lignin alkyl side chains is thought to be responsible for the observed excellent solubilization characteristics acetobromination imparts to a variety of lignin samples. The proposed methodology was compared and contrasted to traditional lignin derivatization methods. In addition, side reactions that could possibly be induced under the acetobromination conditions were explored with native softwood (milled wood lignin, MWL) and technical (kraft) lignin. These efforts lend support toward the use of room temperature acetobromination being a facile, effective, and universal lignin derivatization medium proposed to be employed prior to SEC measurements.     

24(S)-Saringosterol Prevents Cognitive Decline in a Mouse Model for Alzheimer’s Disease

We recently found that dietary supplementation with the seaweed Sargassum fusiforme, containing the preferential LXRβ-agonist 24(S)-saringosterol, prevented memory decline and reduced amyloid-β (Aβ) deposition in an Alzheimer’s disease (AD) mouse model without inducing hepatic steatosis. Here, we examined the effects of 24(S)-saringosterol as a food additive on cognition and neuropathology in AD mice. Six-month-old male APPswePS1ΔE9 mice and wildtype C57BL/6J littermates received 24(S)-saringosterol (0.5 mg/25 g body weight/day) (APPswePS1ΔE9 n = 20; C57BL/6J n = 19) or vehicle (APPswePS1ΔE9 n = 17; C57BL/6J n = 19) for 10 weeks. Cognition was assessed using object recognition and object location tasks. Sterols were analyzed by gas chromatography/mass spectrometry, Aβ and inflammatory markers by immunohistochemistry, and gene expression by quantitative real-time PCR. Hepatic lipids were quantified after Oil-Red-O staining. Administration of 24(S)-saringosterol prevented cognitive decline in APPswePS1ΔE9 mice without affecting the Aβ plaque load. Moreover, 24(S)-saringosterol prevented the increase in the inflammatory marker Iba1 in the cortex of APPswePS1ΔE9 mice (p < 0.001). Furthermore, 24(S)-saringosterol did not affect the expression of lipid metabolism-related LXR-response genes in the hippocampus nor the hepatic neutral lipid content. Thus, administration of 24(S)-saringosterol prevented cognitive decline in APPswePS1ΔE9 mice independent of effects on Aβ load and without adverse effects on liver fat content. The anti-inflammatory effects of 24(S)-saringosterol may contribute to the prevention of cognitive decline.     

The use of ecological traits in extinction risk assessments: A case study on geometrid moths

Identifying ecological traits that make some species more vulnerable than others is vital for predictive conservation science. By identifying these predisposing traits we can predict which species are most prone to decline and gain an understanding of the reasons behind the decline. The aim of this study was to determine the ecological traits that best predict extinction risk and distribution change in Finnish geometrid moths and to develop an understanding of the biological connections between these traits and threats. We found that larval specificity, overwintering stage and flight period length predicted distribution change and extinction risk. There was also an interaction effect between larval specificity and body size on both distribution change and extinction risk. In monophagous species the host plant distribution predicted extinction risk. Even though ecological traits are known to be important determinants of extinction risk, the IUCN red list categorization system is exclusively based on quantitative measures of populations and ignores the ecological traits. Here, we propose that taxon specific ecological data should also be used to predict extinction risk at least on a regional scale to improve the accuracy of the IUCN extinction risk classification.