The Dam1 ring binds to the E-hook of tubulin and diffuses along the microtubule.

There has been much effort in recent years aimed at understanding the molecular mechanism by which the Dam1 kinetochore complex is able to couple microtubule depolymerization to poleward movement. Both a biased diffusion and a forced walk model have been proposed, and several key functional aspects of Dam1-microtubule binding are disputed. Here, we investigate the elements involved in tubulin-Dam1 complex interactions and directly visualize Dam1 rings on microtubules in order to infer their dynamic behavior on the microtubule lattice and its likely relevance at the kinetochore. We find that the Dam1 complex has a preference for native tubulin over tubulin that is lacking its acidic C-terminal tail. Statistical mechanical analysis of images of Dam1 rings on microtubules, applied to both the distance between rings and the tilt angle of the rings with respect to the microtubule axis, supports a diffusive ring model. We also present a cryo-EM reconstruction of the Dam1 ring, likely the relevant assembly form of the complex for energy coupling during microtubule depolymerization in budding yeast. The present studies constitute a significant step forward by linking structural and biochemical observations toward a comprehensive understanding of the Dam1 complex

Southern Mediterranean development through trade, Foreign Direct Investment and migration

Since the launch of the Barcelona Process in 1995 and later the Euro-Mediterranean Partnership, economic relationship between the European Union (EU) and Southern Mediterranean has grown tremendously. Trade volume, in terms of absolute value, between the EU and Southern Mediterranean has grown to an unprecedented height. Although the value has increased, foreign direct investment (FDI) from the EU to Southern Mediterranean remains low. South-to-North migration has also undoubtedly increased given the fact that it has become one of the priority concerns of the EU. Development has taken place through these economic exchanges. However, economic development growth rate remains considerably low compared to that of Latin America and Southeast Asia. This paper discusses about the economic development dynamic of Southern Mediterranean in comparison with that of Latin America and Southeast Asia through economic indicators, economic openness and trade, FDI and migration flows and structures. It also discusses about the challenges faced by Southern Mediterranean and how the economic crisis in the EU may affect their economic relationship.Since the launch of the Barcelona Process in 1995 and later the Euro-Mediterranean Partnership, economic relationship between the European Union (EU) and Southern Mediterranean has grown tremendously. Trade volume, in terms of absolute value, between the EU and Southern Mediterranean has grown to an unprecedented height. Although the value has increased, foreign direct investment (FDI) from the EU to Southern Mediterranean remains low. South-to-North migration has also undoubtedly increased given the fact that it has become one of the priority concerns of the EU. Development has taken place through these economic exchanges. However, economic development growth rate remains considerably low compared to that of Latin America and Southeast Asia. This paper discusses about the economic development dynamic of Southern Mediterranean in comparison with that of Latin America and Southeast Asia through economic indicators, economic openness and trade, FDI and migration flows and structures. It also discusses about the challenges faced by Southern Mediterranean and how the economic crisis in the EU may affect their economic relationship

In vivo microdialysis reveals age-dependent decrease of brain interstitial fluid tau levels in P301S human tau transgenic mice

Although tau is a cytoplasmic protein, it is also found in brain extracellular fluids, e.g., CSF. Recent findings suggest that aggregated tau can be transferred between cells and extracellular tau aggregates might mediate spread of tau pathology. Despite these data, details of whether tau is normally released into the brain interstitial fluid (ISF), its concentration in ISF in relation to CSF, and whether ISF tau is influenced by its aggregation are unknown. To address these issues, we developed a microdialysis technique to analyze monomeric ISF tau levels within the hippocampus of awake, freely moving mice. We detected tau in ISF of wild-type mice, suggesting that tau is released in the absence of neurodegeneration. ISF tau was significantly higher than CSF tau and their concentrations were not significantly correlated. Using P301S human tau transgenic mice (P301S tg mice), we found that ISF tau is fivefold higher than endogenous murine tau, consistent with its elevated levels of expression. However, following the onset of tau aggregation, monomeric ISF tau decreased markedly. Biochemical analysis demonstrated that soluble tau in brain homogenates decreased along with the deposition of insoluble tau. Tau fibrils injected into the hippocampus decreased ISF tau, suggesting that extracellular tau is in equilibrium with extracellular or intracellular tau aggregates. This technique should facilitate further studies of tau secretion, spread of tau pathology, the effects of different disease states on ISF tau, and the efficacy of experimental treatments

Simulations of tubulin sheet polymers as possible structural intermediates in microtubule assembly

The microtubule assembly process has been extensively studied, but the underlying molecular mechanism remains poorly understood. The structure of an artificially generated sheet polymer that alternates two types of lateral contacts and that directly converts into microtubules, has been proposed to correspond to the intermediate sheet structure observed during microtubule assembly. We have studied the self-assembly process of GMPCPP tubulins into sheet and microtubule structures using thermodynamic analysis and stochastic simulations. With the novel assumptions that tubulins can laterally interact in two different forms, and allosterically affect neighboring lateral interactions, we can explain existing experimental observations. At low temperature, the allosteric effect results in the observed sheet structure with alternating lateral interactions as the thermodynamically most stable form. At normal microtubule assembly temperature, our work indicates that a class of sheet structures resembling those observed at low temperature is transiently trapped as an intermediate during the assembly process. This work may shed light on the tubulin molecular interactions, and the role of sheet formation during microtubule assembly.Comment: 43 pages, 13 figures. Submitted; PLoS ONE 200

A serological screening for potential viral pathogens among semi-domesticated Eurasian tundra reindeer (Rangifer tarandus tarandus) in Finland

BackgroundReindeer herding and husbandry is a traditional and important livelihood in Fennoscandia, and about 200,000 semi-domesticated reindeer are herded in Finland. Climatic changes, leading to ice-locked winter pastures, and encroachment of pasture-land have led to changes in reindeer husbandry, increasing the extent of supplementary or full ration feeding, which has become very common in Finland. Keeping reindeer in corrals or gathering them at permanent feeding sites will increase nose-to-nose contact between animals and they may be exposed to poor hygienic conditions. This may impact the epidemiology of infectious diseases, such as viral infections. The aim of this study was to investigate Finnish semi-domesticated reindeer for exposure to viral pathogens. Blood samples were collected from 596 reindeer (358 calves, 238 adults) in 2015, from nine reindeer slaughterhouses, representing most of the reindeer herding regions in Finland. Plasma samples were investigated for antibodies against a selection of known and potential reindeer viral pathogens by using enzyme linked immunosorbent assays (ELISA).ResultsThe screening suggested that alphaherpesvirus and gammaherpesvirus (malignant catarrhal fever virus group; MCFV) were enzootic in the reindeer population, with a seroprevalence of 46.5% (range at slaughterhouse level 28.6-64.3%) and 29.0% (range 3.5-62.2%), respectively. Whereas the seroprevalence was significantly higher for alphaherpesvirus among adult reindeer (91.2%) as compared to calves (16.8%), no age difference was revealed for antibodies against gammaherpesvirus. For alphaherpesvirus, the seroprevalence in the northernmost region, having the highest animal density (animals/km(2)), was significantly higher (55.6%) as compared to the southernmost region (36.2%), whereas the seroprevalence pattern for gammaherpesvirus indicated the opposite, with 8.1% in the north and 50.0% in the south. Four reindeer (0.7%) had antibodies against Pestivirus, whereas no antibodies were detected against Bluetongue virus or Schmallenbergvirus.ConclusionsAlphaherpesvirus and gammaherpesvirus (MCFV) seems to be enzootic in the Finnish reindeer population, similar to other reindeer herds in Fennoscandia, whereas the exposure to Pestivirus was low compared to findings in Norway and Sweden. The ongoing changes in the reindeer herding industry necessitate knowledge on reindeer health and diseases that may impact animal welfare and health of reindeer as well as the economy of the reindeer herding industry.Peer reviewe

Participation of Tom1L1 in EGF-stimulated endocytosis of EGF receptor

Although many proteins have been shown to participate in ligand-stimulated endocytosis of EGF receptor (EGFR), the adaptor protein responsible for interaction of activated EGFR with endocytic machinery remains elusive. We show here that EGF stimulates transient tyrosine phosphorylation of Tom1L1 by the Src family kinases, resulting in transient interaction of Tom1L1 with the activated EGFR bridged by Grb2 and Shc. Cytosolic Tom1L1 is recruited onto the plasma membrane and subsequently redistributes into the early endosome. Mutant forms of Tom1L1 defective in Tyr-phosphorylation or interaction with Grb2 are incapable of interaction with EGFR. These mutants behave as dominant-negative mutants to inhibit endocytosis of EGFR. RNAi-mediated knockdown of Tom1L1 inhibits endocytosis of EGFR. The C-terminal tail of Tom1L1 contains a novel clathrin-interacting motif responsible for interaction with the C-terminal region of clathrin heavy chain, which is important for exogenous Tom1L1 to rescue endocytosis of EGFR in Tom1L1 knocked-down cells. These results suggest that EGF triggers a transient Grb2/Shc-mediated association of EGFR with Tyr-phosphorylated Tom1L1 to engage the endocytic machinery for endocytosis of the ligand–receptor complex

p38 mediates mechanical allodynia in a mouse model of type 2 diabetes

<p>Abstract</p> <p>Background</p> <p>Painful Diabetic Neuropathy (PDN) affects more than 25% of patients with type 2 diabetes; however, the pathogenesis remains unclear due to lack of knowledge of the molecular mechanisms leading to PDN. In our current study, we use an animal model of type 2 diabetes in order to understand the roles of p38 in PDN. Previously, we have demonstrated that the C57BLK db/db (db/db) mouse, a model of type 2 diabetes that carries the loss-of-function leptin receptor mutant, develops mechanical allodynia in the hind paws during the early stage (6-12 wk of age) of diabetes. Using this timeline of PDN, we can investigate the signaling mechanisms underlying mechanical allodynia in the db/db mouse.</p> <p>Results</p> <p>We studied the role of p38 in lumbar dorsal root ganglia (LDRG) during the development of mechanical allodynia in db/db mice. p38 phosphorylation was detected by immunoblots at the early stage of mechanical allodynia in LDRG of diabetic mice. Phosphorylated p38 (pp38) immunoreactivity was detected mostly in the small- to medium-sized LDRG neurons during the time period of mechanical allodynia. Treatment with an antibody against nerve growth factor (NGF) significantly inhibited p38 phosphorylation in LDRG of diabetic mice. In addition, we detected higher levels of inflammatory mediators, including cyclooxygenase (COX) 2, inducible nitric oxide synthases (iNOS), and tumor necrosis factor (TNF)-α in LDRG neurons of db/db mice compared to non-diabetic db+ mice. Intrathecal delivery of SB203580, a p38 inhibitor, significantly inhibited the development of mechanical allodynia and the upregulation of COX2, iNOS and TNF-α.</p> <p>Conclusions</p> <p>Our findings suggest that NGF activated-p38 phosphorylation mediates mechanical allodynia in the db/db mouse by upregulation of multiple inflammatory mediators in LDRG.</p

Efficient dealkalization of red mud and recovery of valuable metals by a sulfur-oxidizing bacterium

Red mud (RM) is a highly alkaline polymetallic waste generated via the Bayer process during alumina production. It contains metals that are critical for a sustainable development of modern society. Due to a shortage of global resources of many metals, efficient large-scale processing of RM has been receiving increasing attention from both researchers and industry. This study investigated the solubilization of metals from RM, together with RM dealkalization, via sulfur (S(0)) oxidation catalyzed by the moderately thermophilic bacterium Sulfobacillus thermosulfidooxidans. Optimization of the bioleaching process was conducted in shake flasks and 5-L bioreactors, with varying S(0):RM mass ratios and aeration rates. The ICP analysis was used to monitor the concentrations of dissolved elements from RM, and solid residues were analyzed for surface morphology, phase composition, and Na distribution using the SEM, XRD, and STXM techniques, respectively. The results show that highest metal recoveries (89% of Al, 84% of Ce, and 91% of Y) were achieved with the S(0):RM mass ratio of 2:1 and aeration rate of 1 L/min. Additionally, effective dealkalization of RM was achieved under the above conditions, based on the high rates (>95%) of Na, K, and Ca dissolution. This study proves the feasibility of using bacterially catalyzed S(0) oxidation to simultaneously dealkalize RM and efficiently extract valuable metals from the amassing industrial waste