292 research outputs found
A New Model for the Evolution of Carnivory in the Bladderwort Plant (Utricularia) : Adaptive Changes in Cytochrome c Oxidase (COX) Provide Respiratory Power
The evolution of carnivorous plants has been modeled as a selective tradeoff between photosynthetic costs and benefits in nutrient-poor habitats. Although possibly applicable for pitfall and flypaper trappers, more variables may be required for active trapping systems. Bladderwort (Utricularia) suction traps react to prey stimuli with an extremely rapid release of elastic instability. Trap setting requires considerable energy to engage an active ion transport process whereby water is pumped out through the thin bladder walls to create negative internal pressure. Accordingly, empirical estimates have shown that respiratory rates in bladders are far greater than in leafy structures. Cytochrome c oxidase (COX) is a multi-subunit enzyme that catalyzes the respiratory reduction of oxygen to water and couples this reaction to translocation of protons, generating a transmembrane electrochemical gradient that is used for the synthesis of adenosine triphosphate (ATP). We have previously demonstrated that two contiguous cysteine residues in helix 3 of COX subunit I (COX I) have evolved under positive Darwinian selection. This motif, absent in = 99.9 % of databased COX I proteins from eukaryotes, Archaea, and Bacteria, lies directly at the docking point of COX I helix 3 and cytochrome c . Modeling of bovine COX I suggests the possibility that a vicinal disulfide bridge at this position could cause premature helix termination. The helix 3â4 loop makes crucial contacts with the active site of COX, and we postulate that the CâC motif might cause a conformational change that decouples (or partly decouples) electron transport from proton pumping. Such decoupling would permit bladderworts to optimize power output (which equals energy times rate) during times of need, albeit with a 20 % reduction in overall energy efficiency of the respiratory chain. A new model for the evolution of bladderwort carnivory is proposed that includes respiration as an additional tradeoff parameter.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74764/1/s-2006-924459.pd
Phylogeography of amphi-boreal fish: tracing the history of the Pacific herring Clupea pallasii in North-East European seas
BackgroundThe relationships between North Atlantic and North Pacific faunas through times have been controlled by the variation of hydrographic circumstances in the intervening Arctic Ocean and Bering Strait. We address the history of trans-Arctic connections in a clade of amphi-boreal pelagic fishes using genealogical information from mitochondrial DNA sequence data. The Pacific and Atlantic herrings (Clupea pallasii and C. harengus) have basically vicarious distributions in the two oceans since pre-Pleistocene times. However, remote populations of C. pallasii are also present in the border waters of the North-East Atlantic in Europe. These populations show considerable regional and life history differentiation and have been recognized in subspecies classification. The chronology of the inter-oceanic invasions and genetic basis of the phenotypic structuring however remain unclear.ResultsThe Atlantic and Pacific herrings both feature high mtDNA diversities (large long-term population sizes) in their native basins, but an ocean-wide homogeneity of C. harengus is contrasted by deep east-west Pacific subdivision within Pacific C. pallasii. The outpost populations of C. pallasii in NE Europe are identified as members of the western Pacific C. pallasii clade, with some retained inter-oceanic haplotype sharing. They have lost diversity in colonization bottlenecks, but have also thereafter accumulated abundant new variation. The data delineate three phylogeographic groups within the European C. pallasii: herring from the inner White Sea; herring from the Mezen and Chesha Bays; and a strongly bottlenecked peripheral population in Balsfjord of the Norwegian Sea.ConclusionsThe NE European outposts of C. pallasii are judged to be early post-glacial colonists from the NW Pacific. A strong regional substructure has evolved since that time, in contrast to the apparent broad-scale uniformity maintained by herrings in their native basins. The structure only partly matches the previous biological concepts based on seasonal breeding stocks or geographical subspecies designations. The trans-Arctic herring phylogeography is notably similar to those of the amphi-boreal mollusk taxa Macoma and Mytilus, suggesting similar histories of inter-oceanic connections. We also considered the time dependency of molecular rates, critical for interpreting timing of relatively recent biogeographical events, by comparing the estimates from coding and non-coding mitochondrial regions of presumably different mutation dynamics
Muistisairaiden liikunnallisen kuntoutuksen vaikuttavuus : Satunnaistettu vertailutukimus
Tutkimuksen tavoitteena oli selvittÀÀ satunnaistetulla,kontrolloidulla asetelmalla liikunnallisen harjoittelun vaikuttavuutta kotona asuvien, Alzheimerin tautia sairastavien
toimintakyvyn eri ulottuvuuksiin, heidĂ€n omaishoitajiensa elĂ€mĂ€nlaatuun sekĂ€ molempien palveluiden kĂ€yttöön ja niiden kustannuksiin vuosina 2008â2011. Tutkimukseen osallistui 210 pariskuntaa, joista toinen puoliso oli muistisairaan omaishoitaja. Pariskunnat randomoitiin kolmeen yhtĂ€ suureen ryhmÀÀn: 1) ryhmĂ€kuntoutusryhmÀÀn (liikuntaharjoittelua
neljÀ tuntia kaksi kertaa viikossa pÀivÀkeskuksessa vuoden ajan), 2) kotikuntoutusryhmÀÀn (tunti kaksi kertaa viikossa kotona vuoden ajan fysioterapeutin ohjauksessa) ja 3) vertailuryhmÀÀn (tavallinen kunnallinen hoito). Tutkimushoitajan haastattelut tehtiin lÀhtötilanteessa sekÀ 3:n, 6:n, 12:n ja 24 kuukauden kohdalla. PÀÀtulosmuuttujat olivat muistisairaan ihmisen
toimintakyky (mitattiin FIM-toimintakykymittarilla)
sekÀ liikuntakyky (mitattiin Guralnikin liikuntakyky- ja tasapainotesteillÀ = SPPB). Kotona annetulla rÀÀtÀlöidyllÀ kuntoutuksella voidaan hidastaa muistisairaiden fyysisen toimintakyvyn (mitattu FIM-mittarilla) heikkenemistÀ merkitsevÀsti. LiikuntatesteissÀ (SPPB) ei ollut eroja ryhmien vÀlillÀ. Myös kognitiossa nÀkyi myönteinen muutos toiminnanohjauksen osalta kellotestillÀ mitattuna kotikuntoutusryhmÀssÀ. RyhmÀkuntoutuksessa palveluiden kokonaiskustannusten sÀÀstöt olivat merkittÀvÀt, joskaan muutokset toimintakyvyssÀ eivÀt saavuttaneet tilastollista merkitsevyyttÀ. Omaisten elÀmÀnlaadussa tai muissa mittareissa ei ollut merkitseviÀ eroja interventioryhmien ja vertailuryhmien vÀlillÀ. Kaatumiset vÀhenivÀt molemmissa interventioryhmissÀ. Kuolemanvaara nÀytti pienentyneen kotikuntoutusryhmÀssÀ. Tutkimuksessa luotiin kuntoutusmalli, joka parantaa Alzheimerin tautia sairastavien toimintakykyÀ lisÀÀmÀttÀ sosiaali- ja terveyspalveluiden kokonaiskustannuksia.15,00 euro
Effects of frequent and long-term exercise on neuropsychiatric symptoms in patients with Alzheimer's disease - Secondary analyses of a randomized, controlled trial (FINALEX)
Background: Neuropsychiatric symptoms (NPS) are common in Alzheimer's disease (AD) and are associated with admission to institutional care. Current guidelines recommend non-pharmacological interventions as the first-line treatment for NPS. However, high-quality randomized studies focused on NPS are scarce. The objective here was to examine whether a regular and long-term exercise programme either at home or as a group-based exercise at an adult day care centre has beneficial effects on AD patients' NPS or permanent institutionalizations. Design, setting, and participants: A randomized, controlled trial with 210 community-dwelling AD patients. Intervention: Two types of intervention comprising (1) group-based exercise in day care centres (GE) and (2) tailored home-based exercise (HE), both twice a week for 12 months, were compared with (3) a control group (CG) receiving usual community care. Measurements: NPS were measured with the Neuropsychiatric Inventory (NPI) at baseline and 6 months, and depression with the Cornell Scale for Depression in Dementia (CSDD) at baseline and 12 months. Data on institutionalizations were retrieved from central registers. Results: No significant differences between the groups were detected in NPI at 6 months or in CSDD at 12 months when analyses were adjusted for age, sex, baseline Clinical Dementia Rating, and Functional Independence Measure. There was no difference in admissions to permanent institutional care between the groups. Conclusions: Regular, long-term exercise intervention did not decrease NPS in patients with AD. (C) 2017 Elsevier Masson SAS and European Union Geriatric Medicine Society. All rights reserved.Peer reviewe
The Ruble between the Hammer and the Anvil: Oil Prices and Economic Sanctions
The exchange rate fluctuations strongly affect the Russian economy, given its heavy dependence on foreign trade and investment. Since January 2014, the Ruble lost 50% of its value against the US Dollar. The fall of the currency started with the conflict between Russia and Ukraine. The impact of the conflict on Russia may have been amplified by sanctions imposed by Western countries. However, as Russia is heavily dependent on exports of natural resources, the oil price decline starting in Summer 2014 could be another factor behind the deterioration. By using high frequency data on nominal exchange and interest rates, oil prices, actual and unanticipated sanctions, we provide evidence on the driving forces of the Ruble exchange rate. The analysis is based on cointegrated VAR models, where fundamental long-run relationships are implicitly embedded. The results indicate that the bulk of the depreciation can be related to the decline of oil prices. In addition, unanticipated sanctions matter for the conditional volatility of the variables involved
Composition and Function of Haemolymphatic Tissues in the European Common Shrew
BACKGROUND: Studies of wild animals responding to their native parasites are essential if we are to understand how the immune system functions in the natural environment. While immune defence may bring increased survival, this may come at a resource cost to other physiological traits, including reproduction. Here, we tested the hypothesis that wild common shrews (Sorex araneus), which produce large numbers of offspring during the one breeding season of their short life span, forgo investment in immunity and immune system maintenance, as increased longevity is unlikely to bring further opportunities for mating. In particular, we predicted that adult shrews, with shorter expected lifespans, would not respond as effectively as young animals to infection. METHODOLOGY/PRINCIPAL FINDINGS: We examined haemolymphatic tissues from wild-caught common shrews using light and transmission electron microscopy, applied in conjunction with immunohistology. We compared composition and function of these tissues in shrews of different ages, and the extent and type of inflammatory reactions observed in response to natural parasitic infections. All ages seemed able to mount systemic, specific immune responses, but adult shrews showed some signs of lymphatic tissue exhaustion: lymphatic follicles in adults (n = 21) were both smaller than those in sub-adults (n = 18; Wald = 11.1, p<0.05) and exhibited greater levels of depletion (Wald = 13.3, p<0.05). CONCLUSIONS/SIGNIFICANCE: Contrary to our expectations, shrews respond effectively to their natural parasites, and show little indication of immunosenescence as adults. The pancreas of Aselli, a unique lymphoid organ, may aid in providing efficient immune responses through the storage of large numbers of plasma cells. This may allow older animals to react effectively to previously encountered parasites, but infection by novel agents, and eventual depletion of plasma cell reserves, could both still be factors in the near-synchronous mortality of adult shrews observed shortly after breeding
The Use of Phage-Displayed Peptide Libraries to Develop Tumor-Targeting Drugs
Monoclonal antibodies have been successfully utilized as cancer-targeting therapeutics and diagnostics, but the efficacies of these treatments are limited in part by the size of the molecules and non-specific uptake by the reticuloendothelial system. Peptides are much smaller molecules that can specifically target cancer cells and as such may alleviate complications with antibody therapy. Although many endogenous and exogenous peptides have been developed into clinical therapeutics, only a subset of these consists of cancer-targeting peptides. Combinatorial biological libraries such as bacteriophage-displayed peptide libraries are a resource of potential ligands for various cancer-related molecular targets. Target-binding peptides can be affinity selected from complex mixtures of billions of displayed peptides on phage and further enriched through the biopanning process. Various cancer-specific ligands have been isolated by in vitro, in vivo, and ex vivo screening methods. As several peptides derived from phage-displayed peptide library screenings have been developed into therapeutics in current clinical trials, which validates peptide-targeting potential, the use of phage display to identify cancer-targeting therapeutics should be further exploited
ViralORFeome: an integrated database to generate a versatile collection of viral ORFs
Large collections of protein-encoding open reading frames (ORFs) established in a versatile recombination-based cloning system have been instrumental to study protein functions in high-throughput assays. Such âORFeomeâ resources have been developed for several organisms but in virology, plasmid collections covering a significant fraction of the virosphere are still needed. In this perspective, we present ViralORFeome 1.0 (http://www.viralorfeome.com), an open-access database and management system that provides an integrated set of bioinformatic tools to clone viral ORFs in the GatewayÂź system. ViralORFeome provides a convenient interface to navigate through virus genome sequences, to design ORF-specific cloning primers, to validate the sequence of generated constructs and to browse established collections of virus ORFs. Most importantly, ViralORFeome has been designed to manage all possible variants or mutants of a given ORF so that the cloning procedure can be applied to any emerging virus strain. A subset of plasmid constructs generated with ViralORFeome platform has been tested with success for heterologous protein expression in different expression systems at proteome scale. ViralORFeome should provide our community with a framework to establish a large collection of virus ORF clones, an instrumental resource to determine functions, activities and binding partners of viral proteins
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