Tallinn University of Technology

About: Tallinn University of Technology is a education organization based out in Tallinn, Estonia. It is known for research contribution in the topics: European union & Oil shale. The organization has 3688 authors who have published 10313 publications receiving 145058 citations. The organization is also known as: Tallinn Technical University & Tallinna Tehnikaülikool.

Neurotrophins: Transcription and Translation

Abstract: Neurotrophins are powerful molecules. Small quantities of these secreted proteins exert robust effects on neuronal survival, synapse stabilization, and synaptic function. Key functions of the neurotrophins rely on these proteins being expressed at the right time and in the right place. This is especially true for BDNF, stimulus-inducible expression of which serves as an essential step in the transduction of a broad variety of extracellular stimuli into neuronal plasticity of physiologically relevant brain regions. Here we review the transcriptional and translational mechanisms that control neurotrophin expression with a particular focus on the activity-dependent regulation of BDNF.

Mainstream-sidestream wastewater switching promotes anammox nitrogen removal rate in organic-rich, low-temperature streams.

Abstract: The main issues with mainstream anammox application are loss of bacterial activity by low temperatures and by a high organic content of wastewater. We demonstrate a novel switching method between s...

Regional variations in diffuse nitrogen losses from agriculture in the Nordic and Baltic regions

Abstract: . This paper describes nitrogen losses from, and the characteristics of, 35 selected catchments (12 to 2000 ha) in the Nordic and Baltic countries. Average annual losses of N in 1994–1997 ranged from 5 to 75 kg ha-1, generally highest and characterised by significant within-country and interannual variations, in Norway and the lowest losses were observed in the Baltic countries. An important finding of the study is that the average nutrient losses varied greatly among the studied catchments. The main explanations for this variability were water runoff, fertiliser use (especially the amount of manure), soil type and erosion (including stream bank erosion). However, there were several exceptions, and it was difficult to find general relationships between the individual factors. For example, there was poor correlation between nitrogen losses and surpluses. Therefore, the results suggest that the observed variability in N losses cannot have been due solely to differences in farm management practices, although the studied catchments do include a wide range of nutrient application levels, animal densities and other relevant elements. There is considerable spatial variation in the physical properties (soil, climate, hydrology, and topography) and the agricultural management of the basins, and the interaction between and relative effects of these factors has an important impact on erosion and nutrient losses. In particular, hydrological processes may have a marked effect on N losses measured in the catchment stream water. The results indicate that significant differences in hydrological pathways (e.g. the relationship between fast- and slow-flow processes) lead to major regional differences in N inputs to surface waters and therefore also in the response to changes in field management practices. Agricultural practices such as crop rotation systems, nutrient inputs and soil conservation measures obviously play a significant role in the site-specific effects, although they cannot explain the large regional differences observed in this study. The interactions between agricultural practices and basic catchment characteristics, including hydrological processes, determine the final losses of nitrogen to surface waters, hence it is necessary to understand these interactions to manage diffuse losses of agricultural nutrients efficiently. Keywords: agriculture, catchments, diffuse sources, nitrogen, losses, Baltic, Nordic

Biophysical studies of the amyloid β-peptide: interactions with metal ions and small molecules

Abstract: Alzheimer's disease is the most common of the protein misfolding ("amyloid") diseases. The deposits in the brains of afflicted patients contain as a major fraction an aggregated insoluble form of the so-called amyloid β-peptides (Aβ peptides): fragments of the amyloid precursor protein of 39-43 residues in length. This review focuses on biophysical studies of the Aβ peptides: that is, of the aggregation pathways and intermediates observed during aggregation, of the molecular structures observed along these pathways, and of the interactions of Aβ with Cu and Zn ions and with small molecules that modify the aggregation pathways. Particular emphasis is placed on studies based on high-resolution and solid-state NMR methods. Theoretical studies relating to the interactions are also included. An emerging picture is that of Aβ peptides in aqueous solution undergoing hydrophobic collapse together with identical partners. There then follows a relatively slow process leading to more ordered secondary and tertiary (quaternary) structures in the growing aggregates. These aggregates eventually assemble into elongated fibrils visible by electron microscopy. Small molecules or metal ions that interfere with the aggregation processes give rise to a variety of aggregation products that may be studied in vitro and considered in relation to observations in cell cultures or in vivo. Although the heterogeneous nature of the processes makes detailed structural studies difficult, knowledge and understanding of the underlying physical chemistry might provide a basis for future therapeutic strategies against the disease. A final part of the review deals with the interactions that may occur between the Aβ peptides and the prion protein, where the latter is involved in other protein misfolding diseases.

An actin cytoskeleton with evolutionarily conserved functions in the absence of canonical actin-binding proteins

Abstract: Giardia intestinalis, a human intestinal parasite and member of what is perhaps the earliest-diverging eukaryotic lineage, contains the most divergent eukaryotic actin identified to date and is the first eukaryote known to lack all canonical actin-binding proteins (ABPs). We sought to investigate the properties and functions of the actin cytoskeleton in Giardia to determine whether Giardia actin (giActin) has reduced or conserved roles in core cellular processes. In vitro polymerization of giActin produced filaments, indicating that this divergent actin is a true filament-forming actin. We generated an anti-giActin antibody to localize giActin throughout the cell cycle. GiActin localized to the cortex, nuclei, internal axonemes, and formed C-shaped filaments along the anterior of the cell and a flagella-bundling helix. These structures were regulated with the cell cycle and in encysting cells giActin was recruited to the Golgi-like cyst wall processing vesicles. Knockdown of giActin demonstrated that giActin functions in cell morphogenesis, membrane trafficking, and cytokinesis. Additionally, Giardia contains a single G protein, giRac, which affects the Giardia actin cytoskeleton independently of known target ABPs. These results imply that there exist ancestral and perhaps conserved roles for actin in core cellular processes that are independent of canonical ABPs. Of medical significance, the divergent giActin cytoskeleton is essential and commonly used actin-disrupting drugs do not depolymerize giActin structures. Therefore, the giActin cytoskeleton is a promising drug target for treating giardiasis, as we predict drugs that interfere with the Giardia actin cytoskeleton will not affect the mammalian host.