Shining a light on the loss of rheophilic fish habitat in lowland rivers as a forgotten consequence of barriers,and its implications for management

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Digital soil mapping using artificial neural networks

In the context of a growing demand of high‐resolution spatial soil information for environmental planning and modeling, fast and accurate prediction methods are needed to provide high‐quality digital soil maps. Thus, this study focuses on the development of a methodology based on artificial neural networks (ANN) that is able to spatially predict soil units. Within a test area in Rhineland‐Palatinate (Germany), covering an area of about 600 km², a digital soil map was predicted. Based on feed‐forward ANN with the resilient backpropagation learning algorithm, the optimal network topology was determined with one hidden layer and 15 to 30 cells depending on the soil unit to be predicted. To describe the occurrence of a soil unit and to train the ANN, 69 different terrain attributes, 53 geologic‐petrographic units, and 3 types of land use were extracted from existing maps and databases. 80% of the predicted soil units (n = 33) showed training errors (mean square error) of the ANN below 0.1, 43% were even below 0.05. Validation returned a mean accuracy of over 92% for the trained network outputs. Altogether, the presented methodology based on ANN and an extended digital terrain‐analysis approach is time‐saving and cost effective and provides remarkable results.     

The Chemically Synthesized Ageladine A-Derivative LysoGlow84 Stains Lysosomes in Viable Mammalian Brain Cells and Specific Structures in the Marine Flatworm Macrostomum lignano

Based on the chemical structure and the known chemical synthesis of the marine sponge alkaloid ageladine A, we synthesized the ageladine A-derivative 4-(naphthalene-2-yl)-1H-imidazo[4,5-c]pyridine trifluoroacetate (LysoGlow84). The two-step synthesis started with the Pictet-Spengler reaction of histamine and naphthalene-2-carbaldehyde to a tetrahydropyridine intermediate, which was dehydrogenated with activated manganese (IV) oxide to LysoGlow84. Structure and purity of the synthesized LysoGlow84 were confirmed by NMR spectroscopy and mass spectrometry. The fluorescence intensity emitted by LysoGlow84 depended strongly on the pH of the solvent with highest fluorescence intensity recorded at pH 4. The fluorescence maximum (at 315 nm excitation) was observed at 440 nm. Biocompatibility of LysoGlow84 was investigated using cultured rat brain astrocytes and the marine flatworm Macrostomum lignano. Exposure of the astrocytes for up to 6 h to micromolar concentrations of LysoGlow84 did not compromise cell viability, as demonstrated by several viability assays, but revealed a promising property of this compound for staining of cellular vesicles. Conventional fluorescence microscopy as well as confocal scanning microscopy of LysoGlow84-treated astrocytes revealed co-localization of LysoGlow84 fluorescence with that of LysoTracker^® Red DND-99. LysoGlow84 stained unclear structures in Macrostomum lignano, which were identified as lysosomes by co-staining with LysoTracker. Strong fluorescence staining by LysoGlow84 was further observed around the worms’ anterior gut and the female genital pore which were not counterstained by LysoTracker Red. Thus, LysoGlow84 is a new promising dye that stains lysosomes and other acidic compartments in cultured cells and in worms.     

Cytotoxic Effects of Tropodithietic Acid on Mammalian Clonal Cell Lines of Neuronal and Glial Origin

The marine metabolite tropodithietic acid (TDA), produced by several Roseobacter clade bacteria, is known for its broad antimicrobial activity. TDA is of interest not only as a probiotic in aquaculture, but also because it might be of use as an antibacterial agent in non-marine or non-aquatic environments, and thus the potentially cytotoxic influences on eukaryotic cells need to be evaluated. The present study was undertaken to investigate its effects on cells of the mammalian nervous system, i.e., neuronal N2a cells and OLN-93 cells as model systems for nerve cells and glia. The data show that in both cell lines TDA exerted morphological changes and cytotoxic effects at a concentration of 0.3–0.5 µg/mL (1.4–2.4 µM). Furthermore, TDA caused a breakdown of the mitochondrial membrane potential, the activation of extracellular signal-regulated kinases ERK1/2, and the induction of the small heat shock protein HSP32/HO-1, which is considered as a sensor of oxidative stress. The cytotoxic effects were accompanied by an increase in intracellular Ca²⁺-levels, the disturbance of the microtubule network, and the reorganization of the microfilament system. Hence, mammalian cells are a sensitive target for the action of TDA and react by the activation of a stress response resulting in cell death.     

The impact of fire and density-dependent mortality on the spatial patterns of a pine forest in the Hulun Buir sandland,Inner Mongolia,China

Wildland fire, especially surface fire, is one of the major disturbances in forest ecosystems such as the Mongolian pine forest of the Hulun Buir sandland. However, little is known about the impact of fire on the spatial patterns at the stand level and its consequences for successional dynamics. To fill this gap we mapped three plots of Mongolian pine forest comprising sites of the same age that were affected by fire in 2006 and 1994, and a site without fire. We explored the stand structure using diameter at breast height (DBH) distributions and basal area, and used point pattern analysis to quantify the observed spatial patterns. Null models included homogeneous Poisson and Thomas cluster processes for univariate analyses, toroidal shift to test for independence, and random labelling for analyzing mortality. Large stems showed at all three stands a tendency to regularity, whereas small stems were mostly clustered. However, small stems did not become more regular at plots with earlier fire, and only the “overstocked” 2006 pre-fire stand showed negative association between large and small trees. Mortality was non-random, showing clustering of dead (or surviving) trees and clear density dependence where stems with more neighbors had a higher risk to die. Fire killed mostly smaller trees and after prolonged fire-free periods the stand approached the pre-fire patterns structurally and spatially. Our study showed that surface fire causes strong thinning in later succession stages and pushes the forest into maturity. It may also enhance resistance of our forest to more severe fire under the relatively harsh environmental conditions. A novel test statistic for random labeling allowed directly testing for density-dependent mortality and could be widely applied in point pattern analysis.     

Isothiocyanate concentration in Kohlrabi (Brassica oleracea L. Var. gongylodes) plants as influenced by sulfur and nitrogen supply

Glucosinolates (GSss) represent bioactive compounds of Brassica vegetables whose health-promoting effects merely stem from their breakdown products, particularly the isothiocyanates (ITCs), released after hydrolysis of GSs by myrosinase. GSs are occasionally discussed as transient S reservoirs, but little is known concerning the interactive effect of S and N supply on ITC concentrations. Therefore, kohlrabi plants were grown in a pot experiment with varied S (0.00, 0.05, and 0.20 g pot (-1)) and N (1, 2, and 4 g pot (-1)) supplies. Plant growth exhibited a classical nutrient response curve with respect to both S and N. The ITC profile of kohlrabi tubers was dominated by methylthiobutyl ITC (11-1350 micromol (g DM) (-1)), followed by sulforaphan (7-120 micromol (g DM) (-1)), phenylethyl ITC (5-34 micromol (g DM) (-1)), and allyl ITC (5-38 micromol (g DM) (-1)), resulting from the hydrolysis of glucoerucin, glucoraphanin, gluconasturtiin, and sinigrin, respectively. The ITC profile was in agreement with reported data, and concentrations of all ITCs were substantially reduced in response to increasing N and decreasing S supply. A growth-induced dilution effect could be ruled out in most cases, and the results do not support the hypothesis that GS acts as transient reservoir with respect to S.     

Novel, binder-free fiber reinforced composites based on a renewable resource from the reed-like plant Typha sp.

The aim of this paper is to demonstrate for the first time the technological potential of novel, totally bio-based, binder-free vegetable fiber-composites based on the reed-like plant Typha sp. Binder-free vegetable fiberboards based on Cattails were prepared and their mechanical (flexural modulus of elasticity, flexural strength and water absorption) and surface textural properties were determined. The influence of press time and panel density on the properties was investigated. In contrast to currently known natural fiber composites based on hemp, flax, kenaf or the like annual plants which all require up to 30 wt% of suitable bonding resins, the typha based composites were prepared completely without the addition of any extraneous glue and showed good mechanical performance that clearly exceeded the performance of other natural fiber composites containing low percentages of phenolic binder (15%). Of special interest were the superior surface properties of the typha based panels. Despite the coarse nature of the raw fiber material and the rough texture of the typha based fiber mats, binder-free typha panels showed excellent surface smoothness which makes this novel composite material highly interesting for light-weight applications with high surface quality standards, for example, as powder-coated elements for the automotive and furniture industries.     

Aplastic articular facets in a dog with intervertebral disk rupture of the 12th to 13th thoracic vertebral space

A 6-year-old, female spayed Pomeranian was presented with acute hind-limb paraplegia with the presence of deep pain perception and urinary incontinence. Myelography showed a Hansen type I herniation of the12th to 13th thoracic intervertebral space (T(12-13)). Articular facets of the T(12-13) and T(13) to first lumbar vertebra (L(1)) were absent. The spinal cord was decompressed using a bilateral T(12-13) modified lateral hemilaminectomy (pediculectomy). The aplastic sites were associated with minimal instability of the vertebral column, and stabilization of the vertebral column was not required. Familiarity with this condition is important, because articular facet aplasia may cause vertebral instability and may require an adjusted surgical approach or vertebral reduction and fusion following decompression.     

Evolution of planetary cores and the Earth-Moon system from Nb/Ta systematics

It has been assumed that Nb and Ta are not fractionated during differentiation processes on terrestrial planets and that both elements are lithophile. High-precision measurements of Nb/Ta and Zr/Hf reveal that Nb is moderately siderophile at high pressures. Nb/Ta values in the bulk silicate Earth (14.0 +/- 0.3) and the Moon (17.0 +/- 0.8) are below the chondritic ratio of 19.9 +/- 0.6, in contrast to Mars and asteroids. The lunar Nb/Ta constrains the mass fraction of impactor material in the Moon to less than 65%. Moreover, the Moon-forming impact can be linked in time with the final core-mantle equilibration on Earth 4.533 billion years ago.