3,620 research outputs found
The diving beetles of Kamchatka, with additional records from Sakhalin and the Kuril Islands (Coleoptera: Dytiscidae).
Die Dytiscidenfauna der nordostasiatischen Halbinsel Kamtschatka wird auf der Grundlage von Literaturnachweisen und neueren Aufsammlungen zusammengestellt. Die folgenden zehn Arten werden erstmals fĂŒr Kamtschatka nachgewiesen: Hygrotus marklini (Gyllenhal), Hydroporus notabilis LeConte, H. submuticus Thomson, H. tristis (Paykull), H. uenoi Nakane, Oreodytes okulovi Lafer, Agabus balkei Fery & Nilsson, A. discolor Harris, Ilybius chishimanus KĂŽno, Rhantus suturellus (Harris), und Graphoderus perplexus Sharp. Insgesamt 38 Dytiscidenarten, davon 22 mit holarktischer Verbreitung, sind nun von Kamtschatka bekannt. Graphoderus perplexus wird erstmals aus der PalĂ€arktis nachgewiesen. Weitere Nachweise werden fĂŒr Sachalin und die Kurilen genannt. Die folgenden Arten sind Erstnachweise fĂŒr Sachalin: Hydroporus nigellus Mannerheim, Agabus kholini Nilsson, Ilybius angustior (Gyllenhal), und Acilius canaliculatus (Nicolai). Zehn Arten werden erstmals fĂŒr die Kurilen nachgewiesen: Hydroporus nigellus, H. notabilis, H. submuticus, H. tristis, Agabus clypealis (Thomson), A. confinis (Gyllenhal), A. costulatus (Motschulsky), A. discolor, Ilybius discedens Sharp, und Colymbetes dahuricus AubĂ©. Neun dieser Arten wurden auf den nördlichen, H. tristis dagegen auf den sĂŒdlichen Kurilen gefunden. Damit sind jetzt von Sachalin 39 und von den Kurilen 36 Arten bekannt.The dytiscid fauna of the north-east Asian peninsula Kamchatka is reviewed based on literature records and more recent collections. The following ten species are here reported from Kamchatka for the first time: Hygrotus marklini (Gyllenhal), Hydroporus notabilis LeConte, H. submuticus Thomson, H. tristis (Paykull), H. uenoi Nakane, Oreodytes okulovi Lafer, Agabus balkei Fery & Nilsson, A. discolor Harris, Ilybius chishimanus KĂŽno, Rhantus suturellus (Harris), and Graphoderus perplexus Sharp. Altogether 38 species of Dytiscidae are now known from Kamchatka, and of these 22 have Holarctic distributions. Graphoderus perplexus is here reported for the Palearctic Region for the first time. Additional records are given for Sakhalin and the Kuril Islands. The following four species are here reported from Sakhalin for the first time: Hydroporus nigellus Mannerheim, Agabus kholini Nilsson, Ilybius angustior (Gyllenhal), and Acilius canaliculatus (Nicolai). The following ten species are here reported from the Kuril Islands for the first time: Hydroporus nigellus, H. notabilis, H. submuticus, H. tristis, Agabus clypealis (Thomson), A. confinis (Gyllenhal), A. costulatus (Motschulsky), A. discolor, Ilybius discedens Sharp, and Colymbetes dahuricus AubĂ©. Nine of the species were found in the North Kurils, whereas H. tristis was found in the South Kurils. With these additions, 39 species are now known from Sakhalin, and 36 from the Kuril Islands
Multiple Origins of Elytral Reticulation Modifications in the West Palearctic Agabus bipustulatus Complex (Coleoptera, Dytiscidae)
The Agabus bipustulatus complex includes one of Europe's most widely distributed and common diving beetles. This complex, which is known for its large morphological variation, has a complex demographic and altitudinal variation in elytral reticulation. The various depth of the reticulation imprint, both in smaller and larger meshes, results in both mat and shiny individuals, as well as intermediate forms. The West Palearctic lowland is inhabited by a sexually dimorphic form, with shiny males and mat females. In mountain regions, shiny individuals of both sexes are found intermixed with mat individuals or in pure populations in central and southern areas, whereas pure populations of mat individuals are exclusively found in the northern region at high altitude. Sexual selection is proposed as a driving force in shaping this variation. However, the occurrence of different types of reticulation in both sexes and disjunct geographical distribution patterns suggest an additional function of the reticulation. Here we investigate the phylogeographical history, genetic structure and reticulation variation of several named forms within the Agabus bipustulatus complex including A. nevadensis. The molecular analyses recognised several well-supported clades within the complex. Several of the named forms had two or more independent origins. Few south European populations were uniform in reticulation patterns, and the males were found to display large variation. Reticulation diversity and population genetic variability were clearly correlated to altitude, but no genetic differences were detected among populations with mixed or homogenous forms. Observed reduction in secondary reticulation in female and increased variance in male at high altitude in South Europe may be explained by the occurrence of an additional selective force, beside sexual selection. The combined effect of these selective processes is here demonstrated in an extreme case to generate isolation barriers between populations at high altitudes. Here we discuss this selective force in relation to thermal selection
Phenotypic and transcriptomic acclimation of the green microalga Raphidocelis subcapitata to high environmental levels of the herbicide diflufenican
Herbicide pollution poses a worldwide threat to plants and freshwater ecosystems. However, the understanding of how organisms develop tolerance to these chemicals and the associated trade-off expenses are largely unknown. This study aims to investigate the physiological and transcriptional mechanisms underlying the acclimation of the green microalgal model species Raphidocelis subcapitata (Selenastraceae) towards the herbicide diflufenican, and the fitness costs associated with tolerance development. Algae were exposed for 12 weeks (corresponding to 100 generations) to diflufenican at the two environmental concentrations 10 and 310 ng/L. The monitoring of growth, pigment composition, and photosynthetic performance throughout the experiment revealed an initial dose-dependent stress phase (week 1) with an EC50 of 397 ng/L, followed by a time-dependent recovery phase during weeks 2 to 4. After week 4, R. subcapitata was acclimated to diflufenican exposure with a similar growth rate, content of carotenoids, and photosynthetic performance as the unexposed control algae. This acclimation state of the algae was explored in terms of tolerance acquisition, changes in the fatty acids composition, diflufenican removal rate, cell size, and changes in mRNA gene expression profile, revealing potential fitness costs associated with acclimation, such as up-regulation of genes related to cell division, structure, morphology, and reduction of cell size. Overall, this study demonstrates that R. subcapitata can quickly acclimate to environmental but toxic levels of diflufenican; however, the acclimation is associated with trade-off expenses that result in smaller cell size
Results on Photon Production in Au+Au Collisions at RHIC
The status of the search for direct photons in Au+Au collisions at sqrt{s_NN}
= 130 GeV and sqrt{s_NN} = 200 GeV with the PHENIX experiment is presented.
Within errors, no excess of direct photons was found in a first analysis pass
done on a limited data set. Significantly reduced systematic and statistical
uncertainties are expected in future analyses.Comment: 4 pages, 3 figures. Talk presented at the Quark Matter 2002
conference, Nantes, France, July 18-24, 2002. To appear in the proceedings
(Nucl. Phys. A
The multifunctional FUS, EWS and TAF15 proto-oncoproteins show cell type-specific expression patterns and involvement in cell spreading and stress response
Background: FUS, EWS and TAF15 are structurally similar multifunctional proteins that were first discovered upon characterization of fusion oncogenes in human sarcomas and leukemias. The proteins belong to the FET ( previously TET) family of RNA-binding proteins and are implicated in central cellular processes such as regulation of gene expression, maintenance of genomic integrity and mRNA/microRNA processing. In the present study, we investigated the expression and cellular localization of FET proteins in multiple human tissues and cell types. Results: FUS, EWS and TAF15 were expressed in both distinct and overlapping patterns in human tissues. The three proteins showed almost ubiquitous nuclear expression and FUS and TAF15 were in addition present in the cytoplasm of most cell types. Cytoplasmic EWS was more rarely detected and seen mainly in secretory cell types. Furthermore, FET expression was downregulated in differentiating human embryonic stem cells, during induced differentiation of neuroblastoma cells and absent in terminally differentiated melanocytes and cardiac muscle cells. The FET proteins were targeted to stress granules induced by heat shock and oxidative stress and FUS required its RNA-binding domain for this translocation. Furthermore, FUS and TAF15 were detected in spreading initiation centers of adhering cells. Conclusion: Our results point to cell-specific expression patterns and functions of the FET proteins rather than the housekeeping roles inferred from earlier studies. The localization of FET proteins to stress granules suggests activities in translational regulation during stress conditions. Roles in central processes such as stress response, translational control and adhesion may explain the FET proteins frequent involvement in human cancer
Challenging claims in the study of migratory birds and climate change
Recent shifts in phenology in response to climate change are well established but often poorly understood. Many animals integrate climate change across a spatially and temporally dispersed annual life cycle, and effects are modulated by ecological interactions, evolutionary change and endogenous control mechanisms. Here we assess and discuss key statements emerging from the rapidly developing study of changing spring phenology in migratory birds. These well-studied organisms have been instrumental for understanding climate-change effects, but research is developing rapidly and there is a need to attack the big issues rather than risking affirmative science. Although we agree poorly on the support for most claims, agreement regarding the knowledge basis enables consensus regarding broad patterns and likely causes. Empirical data needed for disentangling mechanisms are still scarce, and consequences at a population level and on community composition remain unclear. With increasing knowledge, the overall support (âconsensus viewâ) for a claim increased and between-researcher variability in support (âexpert opinions') decreased, indicating the importance of assessing and communicating the knowledge basis. A proper integration across biological disciplines seems essential for the field's transition from affirming patterns to understanding mechanisms and making robust predictions regarding future consequences of shifting phenologies
Reduction of the HIV-1 reservoir in resting CD4+ T-lymphocytes by high dosage intravenous immunoglobulin treatment: a proof-of-concept study
<p>Abstract</p> <p>Background</p> <p>The latency of HIV-1 in resting CD4<sup>+ </sup>T-lymphocytes constitutes a major obstacle for the eradication of virus in patients on antiretroviral therapy (ART). As yet, no approach to reduce this viral reservoir has proven effective.</p> <p>Methods</p> <p>Nine subjects on effective ART were included in the study and treated with high dosage intravenous immunoglobulin (IVIG) for five consecutive days. Seven of those had detectable levels of replication-competent virus in the latent reservoir and were thus possible to evaluate. Highly purified resting memory CD4<sup>+ </sup>T-cells were activated and cells containing replication-competent HIV-1 were quantified. HIV-1 from plasma and activated memory CD4<sup>+ </sup>T-cells were compared with single genome sequencing (SGS) of the <it>gag </it>region. T-lymphocyte activation markers and serum interleukins were measured.</p> <p>Results</p> <p>The latent HIV-1 pool decreased with in median 68% after IVIG was added to effective ART. The reservoir decreased in five, whereas no decrease was found in two subjects with detectable virus. Plasma HIV-1 RNA â„ 2 copies/mL was detected in five of seven subjects at baseline, but in only one at follow-up after 8â12 weeks. The decrease of the latent HIV-1 pool and the residual plasma viremia was preceded by a transitory low-level increase in plasma HIV-1 RNA and serum interleukin 7 (IL-7) levels, and followed by an expansion of T regulatory cells. The magnitude of the viral increase in plasma correlated to the size of the latent HIV-1 pool and SGS of the <it>gag </it>region showed that viral clones from plasma clustered together with virus from activated memory T-cells, pointing to the latent reservoir as the source of HIV-1 RNA in plasma.</p> <p>Conclusion</p> <p>The findings from this uncontrolled proof-of-concept study suggest that the reservoir became accessible by IVIG treatment through activation of HIV-1 gene expression in latently-infected resting CD4<sup>+ </sup>T-cells. We propose that IVIG should be further evaluated as an adjuvant to effective ART.</p
Ligand binding mechanism in steroid receptors; from conserved plasticity to differential evolutionary constraints
Steroid receptor drugs have been available for more than half a century, but details 24 of the ligand binding mechanism has remained elusive. We solved X-ray structures of 25 the glucocorticoid and mineralocorticoid receptors to identify a conserved plasticity at 26 helix 6-7 region that extend the ligand binding pocket towards the receptor surface. 27 Since none of the endogenous ligands exploit this region, we hypothesized that it 28 constitutes an integral part of the binding event. Extensive all atom unbiased ligand 29 exit and entrance simulations corroborate a ligand binding pathway that gives the 30 observed structural plasticity a key functional role. Kinetic measurements reveal that 31 the receptor residence time correlate with structural rearrangements observed in both 32 structures and simulations. Ultimately, our findings reveal why nature has conserved 33 the capacity to open up this region and highlight how differences in the details of the 34 ligand entry process result in differential evolutionary constraints across the steroid 35 receptors.This study was supported by The European Research Council (2009-Adg25027-535 PELE) to V.G and by the SEV-2011-00067 grant of the Severo Ochoa Program. We 536 would like to acknowledge our AstraZeneca colleagues J. Hartleib, R.Unwin and 537 R.Knöll for helpful discussions. We also thank N. Blomberg (ELIXIR) and R. Neutze 538 (University of Gothenburg) for careful reading of the manuscript.Peer ReviewedPostprint (author's final draft
Mental health problems, health risk behaviors, and prevention: A qualitative interview study on perceptions and attitudes among elite male soccer players
BackgroundThe purpose of this study was to investigate the perception of mental health problems and health risk behaviors among Swedish male elite soccer players and their attitudes toward possible prevention strategies.MethodTwenty elite soccer players, aged 15â30 years, were recruited through purposive sampling and interviewed via a digital video calling platform. A semi-structured interview guide, encompassing questions about mental health problems, health risk behaviors among soccer teams, peer-relations, relations to coaches, and attitudes toward health risk behaviors, along with proposals for effective interventions, was employed. The interviews were transcribed verbatim and analyzed with qualitative content analysis.ResultsThe informants reported positive feelings in relation to playing soccer, good health, and few health risk behaviors. Risk factors included a large income, excessive free time, and the need for excitement. Stress and mental health problems were linked to performance pressure, social media, and injuries. Hesitation to talk openly about personal problems due to concerns about negative consequences and the âmacho cultureâ was highlighted as barriers to admit and seek help for personal problems. Some statements indicated openness and the club's efforts to destigmatize personal problems. Positive attitudes toward prevention and suggestions for various measures were prominent.ConclusionFuture research and implementation of interventions should focus on the prevention of health risk behaviors and alleviation of stress and performance pressure, as well as continue the efforts to destigmatize mental health problems and raise awareness among coaches of the importance of their communication and behavior for players' mental health and performance. This could be achieved by developing strategic and systematic policy work, information, and dialogue among players and coaches, in addition to individual digital or face-to-face support, provided by professionals outside the soccer context
PSB33 protein sustains photosystem II in plant chloroplasts under UV-A light
Plants can quickly and dynamically respond to spectral and intensity variations of the incident light. These responses include activation of developmental processes, morphological changes, and photosynthetic acclimation that ensure optimal energy conversion and minimal photoinhibition. Plant adaptation and acclimation to environmental changes have been extensively studied, but many details surrounding these processes remain elusive. The photosystem II (PSII)-associated protein PSB33 plays a fundamental role in sustaining PSII as well as in the regulation of the light antenna in fluctuating light. We investigated how PSB33 knock-out Arabidopsis plants perform under different light qualities. psb33 plants displayed a reduction of 88% of total fresh weight compared to wild type plants when cultivated at the boundary of UV-A and blue light. The sensitivity towards UV-A light was associated with a lower abundance of PSII proteins, which reduces psb33 plants\u27 capacity for photosynthesis. The UV-A phenotype was found to be linked to altered phytohormone status and changed thylakoid ultrastructure. Our results collectively show that PSB33 is involved in a UV-A light-mediated mechanism to maintain a functional PSII pool in the chloroplast
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