Study on the binding of Thioflavin T to beta-sheet-rich and non-beta-sheet cavities

Amyloid fibril formation plays a role in more than 20 diseases including Alzheimer's disease. In vitro detection of these fibrils is often performed using Thioflavin T (ThT), though the ThT binding mode is largely unknown. In the present study, spectral properties of ThT in binding environments representing beta-sheet-rich and non-beta-sheet cavities were examined. Acetylcholinesterase and gamma-cyclodextrin induced a characteristic ThT fluorescence similar to that with amyloid fibrils, whereas beta-cyclodextrin and the beta-sheet-rich transthyretin did not. The cavities of acetylcholinesterase and gamma-cyclodextrin were of similar diameter and only these cavities could accommodate two ThT ions according to molecular modelling. Binding stoichiometry studies also showed a possible binding of two ThT ions. Thus, the characteristic ThT fluorescence is induced in cavities with a diameter of 8-9A and a length able to accommodate the entire length of the ThT ion. The importance of a cavity diameter capable of binding two ThT ions, among others, indicates that an excimer formation is a plausible mechanism for the characteristic fluorescence. We propose a similar ThT binding mode in amyloid fibrils, where cavities of an appropriate size running parallel to the fibril axis have previously been proposed in several amyloid fibril models.     

Modelling predicts that soybean is poised to dominate crop production across Africa

The superior agronomic and human nutritional properties of grain legumes (pulses) make them an ideal foundation for future sustainable agriculture. Legume‐based farming is particularly important in Africa, where small‐scale agricultural systems dominate the food production landscape. Legumes provide an inexpensive source of protein and nutrients to African households as well as natural fertilization for the soil. Although the consumption of traditionally grown legumes has started to decline, the production of soybeans (Glycine max Merr.) is spreading fast, especially across southern Africa. Predictions of future land‐use allocation and production show that the soybean is poised to dominate future production across Africa. Land use models project an expansion of harvest area, whereas crop models project possible yield increases. Moreover, a seed change in farming strategy is underway. This is being driven largely by the combined cash crop value of products such as oils and the high nutritional benefits of soybean as an animal feed. Intensification of soybean production has the potential to reduce the dependence of Africa on soybean imports. However, a successful “soybean bonanza” across Africa necessitates an intensive research, development, extension, and policy agenda to ensure that soybean genetic improvements and production technology meet future demands for sustainable production.     

Proteomic responses to ocean acidification of the marine diazotroph Trichodesmium under iron-replete and iron-limited conditions

Photosynthesis Research - Growth and dinitrogen (N2) fixation of the globally important diazotrophic cyanobacteria Trichodesmium are often limited by iron (Fe) availability in surface seawaters. To...     

Critical swimming speed of sterlet (Acipenser ruthenus): Does intraspecific hybridization affect swimming performance?

We studied the effect of intraspecific hybridization on swimming performance in sterlet, hypothesizing that such hybridization increases the performance by inducing the hybrid vigor. A total of 12 purebred and hybrid crosses were reproduced from Danube (D) and Volga (V) populations of Acipenser ruthenus. Within each cross, one group of fish was exposed to temperature challenges mimicking the temperature variation in the natural environment during summer. Temperature challenges comprised a constant increase from 19°C to 24°C and then return to 19°C within 12 hr (dT<1°C/hr), and were carried out every third day over the experimental period of 20 days. As a control, fish from each cross were kept at a constant temperature of 19°C. Critical swimming speed (U_crit) was assessed on day 0 (29 days post hatch, dph), 10 (39 dph) and 20 (49 dph). The critical swimming speeds ranged from 5.12 cm/s (1.63 TL/s) to 16.44 cm/s (2.4 TL/s) during the experimental period (29–49 dph). There were no significant differences observed in U_crit between repeatedly temperature challenged and control groups, indicating that the temperature challenge did not alter the swimming performance. The critical swimming speed showed positive relationship with total body length. Comparing intraspecific hybrid crosses with purebred crosses, no significant difference in swimming performance was observed. It is thus concluded that swimming performance is a family specific trait. There is no indication that intraspecific hybridization affects swimming performance nor that close‐to‐natural temperature regimes increase swimming performance.     

Declining population trends of European mountain birds

Mountain areas often hold special species communities, and they are high on the list of conservation concern. Global warming and changes in human land use, such as grazing pressure and afforestation, have been suggested to be major threats for biodiversity in the mountain areas, affecting species abundance and causing distribution shifts towards mountaintops. Population shifts towards poles and mountaintops have been documented in several areas, indicating that climate change is one of the key drivers of species’ distribution changes. Despite the high conservation concern, relatively little is known about the population trends of species in mountain areas due to low accessibility and difficult working conditions. Thanks to the recent improvement of bird monitoring schemes around Europe, we can here report a first account of population trends of 44 bird species from four major European mountain regions: Fennoscandia, UK upland, south‐western (Iberia) and south‐central mountains (Alps), covering 12 countries. Overall, the mountain bird species declined significantly (?7%) during 2002–2014, which is similar to the declining rate in common birds in Europe during the same period. Mountain specialists showed a significant ?10% decline in population numbers. The slope for mountain generalists was also negative, but not significantly so. The slopes of specialists and generalists did not differ from each other. Fennoscandian and Iberian populations were on average declining, while in United Kingdom and Alps, trends were nonsignificant. Temperature change or migratory behaviour was not significantly associated with regional population trends of species. Alpine habitats are highly vulnerable to climate change, and this is certainly one of the main drivers of mountain bird population trends. However, observed declines can also be partly linked with local land use practices. More efforts should be undertaken to identify the causes of decline and to increase conservation efforts for these populations.     

Fine grinding or expanding of feed as pre-treatment for pelleting in dependence on dietary rapeseed expeller proportion: Nutritional consequences for broilers

Although commercial broiler feed is usually differently conditioned before pelleting, the nutritional consequences of fine grinding or expanding as pre-pelleting treatments are poorly defined so far. Therefore, the effects of these two pre-treatments on nutrient digestibility, broiler performance and digestive tract of broilers were tested. In order to investigate possible interactions between pre-treatments and diet composition two diets differing in rapeseed expeller proportion were tested in a two by two factorial design. Thus, four diets were designed including two diets containing 6% rapeseed expeller (RSE) which were pre-treated by fine grinding (6%FgP) or expanding (6%ExP), and two corresponding diets containing 12% RSE (12%FgP and 12%ExP). For the experiments, 864 male broilers were used. There was a significant diet-by-technical feed treatment (TFT) interaction in case of the digestibility of all considered crude nutrients (p < 0.05). Diet 6%ExP showed higher crude protein digestibility compared to other feeds (p < 0.001). The highest digestibility of organic matter, ether extract, crude fibre and N-free extractives achieved diet 12%FgP. Diets 6%ExP and 12%FgP showed higher N-corrected metabolisable energy content (p < 0.001). TFT affected daily feed intake (DFI) and body weight (BW) gain in a diet-dependent manner (p < 0.001). Feeding of 6%FgP enhanced DFI and BW gain compared to other feeds but 6%ExP reduced both parameters (p < 0.001). Weights of proventriculi and gizzards of animals fed 6%ExP were increased compared with 6%FgP (p < 0.01). In contrast, proventricular length in animals fed 6%FgP was increased compared with diet 6%ExP (p = 0.042). Moreover, animals fed 6%FgP had wider proventriculi than animals fed 12%FgP (p = 0.023). Feed 6%ExP increased proventricular weight compared to 12%ExP (p = 0.001). With regard to the strong relationships between diet and TFT no specific processing method can be recommended according to considered nutritional aspects. A marked prevention of proventricular dilatation due to pellet feeding could not be realised by various used TFT or feed formulations. Used amounts of RSE had no obvious adverse effects on considered nutritional aspects.     

Prdm12 Directs Nociceptive Sensory Neuron Development by Regulating the Expression of the NGF Receptor TrkA

1. Download high-res image (294KB)
2. Download full-size image

     

Microbial metal-sulfide oxidation in inactive hydrothermal vent chimneys suggested by metagenomic and metaproteomic analyses

Metal-sulfides are wide-spread in marine benthic habitats. At deep-sea hydrothermal vents, they occur as massive sulfide chimneys formed by mineral precipitation upon mixing of reduced vent fluids with cold oxygenated sea water. Although microorganisms inhabiting actively venting chimneys and utilizing compounds supplied by the venting fluids are well studied, only little is known about microorganisms inhabiting inactive chimneys. In this study, we combined 16S rRNA gene-based community profiling of sulfide chimneys from the Manus Basin (SW Pacific) with radiometric dating, metagenome (n = 4) and metaproteome (n = 1) analyses. Our results shed light on potential lifestyles of yet poorly characterized bacterial clades colonizing inactive chimneys. These include sulfate-reducing Nitrospirae and sulfide-oxidizing Gammaproteobacteria dominating most of the inactive chimney communities. Our phylogenetic analysis attributed the gammaproteobacterial clades to the recently described Woeseiaceae family and the SSr-clade found in marine sediments around the world. Metaproteomic data identified these Gammaproteobacteria as autotrophic sulfide-oxidizers potentially facilitating metal-sulfide dissolution via extracellular electron transfer. Considering the wide distribution of these gammaproteobacterial clades in marine environments such as hydrothermal vents and sediments, microbially accelerated neutrophilic mineral oxidation might be a globally relevant process in benthic element cycling and a considerable energy source for carbon fixation in marine benthic habitats.