Linking colonies to fisheries: Spatio-temporal overlap between common murres (Uria aalge) from Tatoosh Island and coastal gillnet fisheries in the Pacific Northwest, USA

The population-level impact of seabird bycatch is difficult to assess because colony-of-origin is often unknown. As an alternative and complementary approach to ship-derived observations, we assessed the relative potential for bycatch of a known seabird population by quantifying spatio-temporal overlap with local fisheries. Common murres (Uria aalge) have been reported as the most abundant seabird inadvertently caught in Washington and British Columbia coastal gillnet fisheries. In 1999-2001, we tracked 48 common murres from Tatoosh Island, the closest colony to the fisheries, during post-breeding. Using capture-mark-recapture models, we estimated weekly murre movement probabilities to/from three strata (offshore of, centered around, and inshore of Tatoosh Island). Based on movement probabilities and population size, we projected strata- and week-specific murre abundance. We created an index of overlap by calculating the product of murre abundance × gillnet fishing effort as a function of strata and time. The majority of murres (80%) moved inshore, where fishing effort was consistently the highest, suggesting that up to 4000 Tatoosh murres were vulnerable to bycatch. Index scores in the inshore stratum were 5-25 times higher relative to the offshore and Tatoosh strata, respectively. Overlap was sensitive to phenology, as index scores increased by 50% when dispersal was shifted four weeks earlier, while a two weeks delay decreased scores by 20%. Until the long-term impact of cumulative mortality in gillnet fisheries is determined, we believe a precautionary approach is warranted in the inshore stratum where the potential for bycatch was highest. We advocate the use of visible netting in inshore fisheries, a proven solution that reduces murre bycatch while maintaining fishing efficiency.     

Landscape patch shape complexity as an effective measure for plant species richness in rural landscapes

The application of landscape patch shape complexity as a predictor ofvascularplant and bryophyte species richness is analysed. Several common complexityindices (shape index, fractal dimension, comparison to the area of the minimumbounding rectangle) are tested for their predictive power for plant speciesrichness. One new robust measure for shape complexity is presented whichovercomes some disadvantages of common complexity measures applied to highresolution analysis of agricultural landscapes based on aerial photographs. Thenew index is based on the number of shape characterising points along apolygons boundary. This new measure shows promising predictive capabilitiesforspecies richness of vascular plants and bryophytes (correlation coefficient:0.85 for vascular plants, 0.74 for bryophytes).This revised version was published online in May 2005 with corrections to the Cover Date.     

Activation of stress-responsive mitogen-activated protein kinase pathways in hybrid poplar (Populus trichocarpa x Populus deltoides)

Plant mitogen-activated protein kinase (MAPK) cascades are important amplifying modules that can rapidly transduce stress signals into various appropriate intracellular responses. Several extracellular regulated kinase (ERK)-type MAPKs involved in plant defense signaling have been identified in herbaceous species, but no MAPK cascade has yet been characterized in a tree species. We examined the signal transduction events that lead to activation of defense mechanisms in poplar, a major forest species of economic and ecological importance which is becoming the model tree system for studying stress and adaptation responses. We show that, in poplar cell suspensions and leaf tissue, chitosan, a non-host-specific elicitor, and ozone, a strong oxidant and atmospheric pollutant, induce rapid and transient activation of at least two myelin basic protein (MBP) kinases with apparent molecular masses of 44 and 47 kD. The chitosan- and ozone-activated kinases have characteristics of MAPKs-they preferentially phosphorylate MBP, require tyrosine and threonine phosphorylation to be activated and are specifically recognized by anti-ERK and anti-pERK antibodies. Moreover, activation of these poplar MAPKs by chitosan or ozone is dependent on the production of reactive oxygen species; the influx of calcium ions via membrane channels; the activation of an upstream, membrane-localized component; and a cognate MAPK kinase (MAPKK). These data suggest that biotic and abiotic challenges activate MAPKs in poplar, as in herbaceous species, which then function as a convergence point for pathogen defense and oxidant stress signaling cascades.     

Evaluating the accuracy and generality of a hybrid patch model

Forest patch models have been used extensively to simulate vegetation development under current and changing environmental conditions. However, their physiological foundation is subject to criticism and recent validation experiments against long-term growth and yield data have shown major deficiencies in reproducing observed growth patterns of mixed-species forests. Here we describe the modified forest patch model PICUS Version 1.3, a model variant that couples the structurally detailed three-dimensional patch model PICUS Version 1.2 and the physiologically based stand-level production module of the 3-PG (Physiological Principles in Predicting Growth) model. The approach attempts to combine the ability of PICUS v1.2 to simulate forest dynamics on time scales relevant to forest succession with a simplified but successful production model based on the concept of radiation-use efficiency. We evaluated the hybrid model in a series of simulation experiments. Results indicated a realistic response to a climate sensitivity experiment: the response to environmental gradients was well captured both in terms of productivity on time scales of a rotation length and of forest succession over several hundreds of years. Testing against independent long- term growth and yield data revealed good correspondence between observed and predicted values of volume production and stand structure. Further model development should include a dynamic soil component to consider effects of nutrient cycling.     

Elimination of heavy metals from process waters of the bioleaching process by electrolysis

2 Conclusions  The investigations into the membrane electrolysis cell show that electrochemical metal separation from bioleaching process waters can represent a practical alternative for metal separation by alcalization, Coal and platinized titanium material exhibit good anodic resistance at the current densities tested. By contrast, high-grade steel and to some extent lead anodes were dissolved and are hence unsuitable for this purpose. However, for practical application, suitable ways are required to discharge the precipitates containing heavy metals deposited on the electrodes from the electrolysis cell and to prevent membrane clogging. Regarding the main components zinc, manganese, and nickel, the combination electrodes proved to be suitable for eliminating the heavy metals from the aqueous phase. Another way of treating diluted process waters containing sulphuric acidic and heavy metals is to concentrate the sulphuric acid in the anode region and to precipitate the heavy metals in the cathode region. The sulphuric acid recovered could then be returned to the leaching process, hence avoiding wastewater.     

Homodimeric β-galactosidase from Lactobacillus delbrueckii subsp. bulgaricus DSM 20081: expression in Lactobacillus plantarum and biochemical characterization

The lacZ gene from Lactobacillus delbrueckii subsp. bulgaricus DSM 20081, encoding a β-galactosidase of the glycoside hydrolase family GH2, was cloned into different inducible lactobacillal expression vectors for overexpression in the host strain Lactobacillus plantarum WCFS1. High expression levels were obtained in laboratory cultivations with yields of approximately 53000 U of β-galactosidase activity per liter of medium, which corresponds to ~170 mg of recombinant protein per liter and β-galactosidase levels amounting to 63% of the total intracellular protein of the host organism. The wild-type (nontagged) and histidine-tagged recombinant enzymes were purified to electrophoretic homogeneity and further characterized. β-Galactosidase from L. bulgaricus was used for lactose conversion and showed very high transgalactosylation activity. The maximum yield of galacto-oligosaccharides (GalOS) was approximately 50% when using an initial concentration of 600 mM lactose, indicating that the enzyme can be of interest for the production of GalOS.     

Regionalization of Magnetic Susceptibility Measurements Based on a Multiple Regression Approach

The article presents results of a case study in northeastern Germany, where magnetic susceptibility assessment was carried out at grid-wise field measurements. The measurements were clustered into three different depth levels, which represent the humus layer, the transition zone between humus layer and mineral horizon, and the mineral horizon. Taking these three depth levels, a multiple regression-based regionalization approach was applied, testing and using additional environmental parameters derived from geology, topography, and stand type with the aim to develop a comprehensive model for spatial variability of magnetic susceptibility. Spatial variation of magnetic susceptibility was predicted with a high precision by the multiple linear regression models. A slightly differing set of model parameters was selected for the single depth levels. In tendency, magnetic susceptibility values in depth level 6–10 cm were best explained by the distance to Bitterfeld and by soil properties. In depth level 11–15 cm, variables which describe the orographic conditions and stand properties gain in importance. In depth level 21–25 cm, variables indicating soil and site properties disappear completely. Here, aspect and land surface characteristics play a major role together with stand properties. A spatial stratification of the model for a distance of up to 25 km to the former emitters provided a further improvement of the model quality considering the prediction of small-scale variations of magnetic susceptibility.     

Comparison between discontinuous and continuous lactose conversion processes for the production of prebiotic galacto-oligosaccharides using beta-galactosidase from Lactobacillus reuteri

Galacto-oligosaccharide (GOS) formation from lactose in discontinuous and continuous modes of conversion was investigated using beta-galactosidase (beta-gal) from Lactobacillus reuteri. A continuous stirred tank reactor (CSTR) with an external crossflow membrane was set up, and continuous GOS production was analyzed and compared to the batchwise formed GOS product. Marked differences were detected for the two reactor setups. Above 65% lactose conversion, the GOS yield was lower for the CSTR due to a lower content of tri- and tetrasaccharides in the reaction mixture. In the CSTR, beta-gal from L. reuteri showed up to 2-fold higher specificity toward the formation of beta-(1-->6)-linked GOS, with beta-D-Galp-(1-->6)-D-Glc and beta-D-Galp-(1-->6)-D-Gal being the main GOS components formed under these conditions. This could be used to synthesize more defined GOS products.     

Amphiregulin, a TH2 cytokine enhancing resistance to nematodes

Although type 2 immune responses contribute to allergy and asthma, these responses are essential for clearing intestinal helminth infestations by mechanisms that include increased epithelial shedding. We show that T helper 2 cells (T(H)2), but not other T cell subsets, express amphiregulin, a member of the epidermal growth factor (EGF) family. EGF receptor ligands directly induce epithelial cell proliferation, and lack of amphiregulin delayed expulsion of the nematode Trichuris muris. This newly recognized link between T(H)2 cells and epithelial proliferation should help in planning therapeutic interventions for helminth infections and other diseases that involve both cell proliferation and allergy, such as asthma.     

Compaction of forest soils with heavy logging machinery affects soil bacterial community structure

Soil compaction is widespread but tends to be most prevalent where heavy machinery is used in landfill sites, agriculture and forestry. Three forest sites strongly disturbed by heavy logging machinery were chosen to test the physical effects of different levels of compaction on soil bacterial community structure and soil functions. Community analysis comprised microbial biomass C and T-RFLP genetic profiling. Machine passes, irrespective of the compaction level, considerably modified soil structural characteristics at two soil depths (5–10 cm; 15–20 cm). Total porosity decreased up to 17% in the severe compaction. Reflected in this overall decline were large decreases in macroporosity (>50 μm). Reduction in macroporosity was associated with higher water retention and restricted gas exchange in compacted soils. The strongest effect was observed in the severely compacted wheel tracks where air and water conductivities were reduced permanently to 10% or even lower of the original conductivities of undisturbed soils. Very slow drainage in combination with a dramatically reduced gas permeability led to unfavorable soil conditions in severely disturbed traffic lanes reflecting the changes in the total bacterial community structures at both soil depths. Additionally, microbial biomass C tended to be lower in compacted soil. Our results indicate that the type of severe treatments imposed at these forest sites may have strong adverse effects on long-term soil sustainability.