229 research outputs found

    Detecting Compaction Disequilibrium with Anisotropy of Magnetic Susceptibility

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    In clay-rich sediment, microstructures and macrostructures influence how sediments deform when under stress. When lithology is fairly constant, anisotropy of magnetic susceptibility (AMS) can be a simple technique for measuring the relative consolidation state of sediment, which reflects the sediment burial history. AMS can reveal areas of high water content and apparent overconsolidation associated with unconformities where sediment overburden has been removed. Many other methods for testing consolidation and water content are destructive and invasive, whereas AMS provides a nondestructive means to focus on areas for additional geotechnical study. In zones where the magnetic minerals are undergoing diagenesis, AMS should not be used for detecting compaction state. By utilizing AMS in the Santa Barbara Basin, we were able to identify one clear unconformity and eight zones of high water content in three cores. With the addition of susceptibility, anhysteretic remanent magnetization, and isothermal remanent magnetization rock magnetic techniques, we excluded 3 out of 11 zones from being compaction disequilibria. The AMS signals for these three zones are the result of diagenesis, coring deformation, and burrows. In addition, using AMS eigenvectors, we are able to accurately show the direction of maximum compression for the accumulation zone of the Gaviota Slide

    Increasing Resiliency to Natural Hazardsβ€”A Strategic Plan for the Multi-Hazards Demonstration Project in Southern California

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    The U.S. Geological Survey (USGS) is initiating a new project designed to improve resiliency to natural hazards in southern California through the application of science to community decision making and emergency response. The Multi-Hazards Demonstration Project will assist the region’s communities to reduce their risk from natural hazards by directing new and existing research towards the community’s needs, improving monitoring technology, producing innovative products, and improving dissemination of the results. The natural hazards to be investigated in this project include coastal erosion, earthquakes, floods, landslides, tsunamis, and wildfires. Americans are more at risk from natural hazards now than at any other time in our Nation’s history. Southern California, in particular, has one of the Nation’s highest potentials for extreme catastrophic losses due to natural hazards, with estimates of expected losses exceeding $3 billion per year. These losses can only be reduced through the decisions of the southern California community itself. To be effective, these decisions must be guided by the best information about hazards, risk, and the cost-effectiveness of mitigation technologies. The USGS will work with collaborators to set the direction of the research and to create multi-hazard risk frameworks where communities can apply the results of scientific research to their decision-making processes. Partners include state, county, city, and public-lands government agencies, public and private utilities, companies with a significant impact and presence in southern California, academic researchers, the Federal Emergency Management Agency (FEMA), National Oceanic and Atmospheric Administration (NOAA), and local emergency response agencies. Prior to the writing of this strategic plan document, three strategic planning workshops were held in February and March 2006 at the USGS office in Pasadena to explore potential relationships. The goal of these planning sessions was to determine the external organizations’ needs for mitigation efforts before potential natural hazard events, and response efforts during and after the event. On the basis of input from workshop participants, four priority areas were identified for future research to address. They are (1) helping decision makers design planning scenarios, (2) improving upon the mapping of multiple hazards in urban areas, (3) providing real-time information from monitoring networks, and (4) integrating information in a risk and decision-making analysis. Towards this end, short-term and out-year goals have been outlined with the priorities in mind. First-year goals are (1) to engage the user community to establish the structures and processes for communications and interactions, (2) to develop a program to create scenarios of anticipated disasters, beginning in the first year with a scenario of a southern San Andreas earthquake that triggers secondary hazards, (3) to compile existing datasets of geospatial data, and (4) to target research efforts to support more complete and robust products in future years. Both the first-year and out-year goals have been formulated around a working-group structure that builds on existing research strengths within the USGS. The project is intended to demonstrate how developments in methodology and products can lead to improvement in our management of natural hazards in an urban environment for application across the Nation

    Inner tegument protein pUL37 of herpes simplex virus type 1 is involved in directing capsids to the trans-Golgi network for envelopment

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    Secondary envelopment of herpes simplex virus type 1 has been demonstrated as taking place at the trans-Golgi network (TGN). The inner tegument proteins pUL36 and pUL37 and the envelope glycoproteins gD and gE are known to be important for secondary envelopment. We compared the cellular localizations of capsids from a virus mutant lacking the UL37 gene with those of a virus mutant lacking the genes encoding gD and gE. Although wild-type capsids accumulated at the TGN, capsids of the pUL37βˆ’ mutant were distributed throughout the cytoplasm and showed no association with TGN-derived vesicles. This was in contrast to capsids from a gDβˆ’gEβˆ’ mutant, which accumulated in the vicinity of TGN vesicles, but did not colocalize with them, suggesting that they were transported to the TGN but were unable to undergo envelopment. We conclude that the inner tegument protein pUL37 is required for directing capsids to the TGN, where secondary envelopment occurs

    Effects of lanosterol on in vitro maturation of porcine oocytes

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    [EN] FF-MAS and T-MAS sterols, intermediaries in the cholesterol biosynthetic pathway present in all cells, may represent the physiological signal that instructs the crocyte to reinitiate meiosis. The purpose of this study was to examine the hypothesis that exogenous lanosterol could be included in the sterol biosynthetic pathway from acetate to cholesterol and induce resumption of meiosis in oocytes cultured in vitro. Porcine oocytes were in vitro matured in medium supplemented with different concentrations of lanosterol. First, after 22 h of in vitro maturation, cumulus cells were recovery and Delta 7-Reductase gene expression was quantified using real-time PCR. Second, after 44 h of in vitro maturation, chromatin configuration was evaluated using Hoechst 33342. Lipid content was also evaluated at 22 and 44 In of in vitro maturation using Nile red staining. The results showed that the addition of lanosterol increased the Delta 7-Reductase gene expression and influenced resumption of meiosis using 50 and 100 mu M, as well as enhancing higher cytoplasmic lipid accumulation after in vitro maturation. The results demonstrate that exogenous lanosterol acts in the sterol biosynthetic pathway from acetate to cholesterol and it was responsible for a higher resumption of meiosis in porcine oocytes cultured in vitro. (C) 2009 Elsevier B.V. All rights reserved.Supported by the Universidad Politecnica de Valencia (Project 20081166).Marco JimΓ©nez, F.; Llobat, L.; Vicente AntΓ³n, JS. (2010). Effects of lanosterol on in vitro maturation of porcine oocytes. Animal Reproduction Science. 117(3-4):288-294. https://doi.org/10.1016/j.anireprosci.2009.04.008S2882941173-

    The transport mechanism of the mitochondrial ADP/ATP carrier

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    The mitochondrial ADP/ATP carrier imports ADP from the cytosol and exports ATP from the mitochondrial matrix, which are key transport steps for oxidative phosphorylation in eukaryotic organisms. The transport protein belongs to the mitochondrial carrier family, a large transporter family in the inner membrane of mitochondria. It is one of the best studied members of the family and serves as a paradigm for the molecular mechanism of mitochondrial carriers. Structurally, the carrier consists of three homologous domains, each composed of two transmembrane Ξ±-helices linked with a loop and short Ξ±-helix on the matrix side. The transporter cycles between a cytoplasmic and matrix state in which a central substrate binding site is alternately accessible to these compartments for binding of ADP or ATP. On both the cytoplasmic and matrix side of the carrier are networks consisting of three salt bridges each. In the cytoplasmic state, the matrix salt bridge network is formed and the cytoplasmic network is disrupted, opening the central substrate binding site to the intermembrane space and cytosol, whereas the converse occurs in the matrix state. In the transport cycle, tighter substrate binding in the intermediate states allows the interconversion of conformations by lowering the energy barrier for disruption and formation of these networks, opening and closing the carrier to either side of the membrane in an alternating way. Conversion between cytoplasmic and matrix states might require the simultaneous rotation of three domains around a central translocation pathway, constituting a unique mechanism among transport proteins. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou

    Calcium ion currents mediating oocyte maturation events

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    During maturation, the last phase of oogenesis, the oocyte undergoes several changes which prepare it to be ovulated and fertilized. Immature oocytes are arrested in the first meiotic process prophase, that is morphologically identified by a germinal vesicle. The removal of the first meiotic block marks the initiation of maturation. Although a large number of molecules are involved in complex sequences of events, there is evidence that a calcium increase plays a pivotal role in meiosis re-initiation. It is well established that, during this process, calcium is released from the intracellular stores, whereas less is known on the role of external calcium entering the cell through the plasma membrane ion channels. This review is focused on the functional role of calcium currents during oocyte maturation in all the species, from invertebrates to mammals. The emerging role of specific L-type calcium channels will be discussed

    Phylogenomic analysis of a 55.1 kb 19-gene dataset resolves a monophyletic Fusarium that includes the Fusarium solani Species Complex

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    Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-userΒΏs needs and established successful practice. In 2013, the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani species complex (FSSC). Subsequently, this concept was challenged in 2015 by one research group who proposed dividing the genus Fusarium into seven genera, including the FSSC described as members of the genus Neocosmospora, with subsequent justification in 2018 based on claims that the 2013 concept of Fusarium is polyphyletic. Here, we test this claim and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a genus Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students, and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species described as genus Neocosmospora were recombined in genus Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural, and practical taxonomic option availabl

    Impact of Marine Drugs on Animal Reproductive Processes

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    The discovery and description of bioactive substances from natural sources has been a research topic for the last 50 years. In this respect, marine animals have been used to extract many new compounds exerting different actions. Reproduction is a complex process whose main steps are the production and maturation of gametes, their activation, the fertilisation and the beginning of development. In the literature it has been shown that many substances extracted from marine organisms may have profound influence on the reproductive behaviour, function and reproductive strategies and survival of species. However, despite the central importance of reproduction and thus the maintenance of species, there are still few studies on how reproductive mechanisms are impacted by marine bioactive drugs. At present, studies in either marine and terrestrial animals have been particularly important in identifying what specific fine reproductive mechanisms are affected by marine-derived substances. In this review we describe the main steps of the biology of reproduction and the impact of substances from marine environment and organisms on the reproductive processes

    Viral capsids: Mechanical characteristics, genome packaging and delivery mechanisms

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    The main functions of viral capsids are to protect, transport and deliver their genome. The mechanical properties of capsids are supposed to be adapted to these tasks. Bacteriophage capsids also need to withstand the high pressures the DNA is exerting onto it as a result of the DNA packaging and its consequent confinement within the capsid. It is proposed that this pressure helps driving the genome into the host, but other mechanisms also seem to play an important role in ejection. DNA packaging and ejection strategies are obviously dependent on the mechanical properties of the capsid. This review focuses on the mechanical properties of viral capsids in general and the elucidation of the biophysical aspects of genome packaging mechanisms and genome delivery processes of double-stranded DNA bacteriophages in particular
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