107 research outputs found

    Mistletoe lectin is not the only cytotoxic component in fermented preparations of Viscum album from white fir (Abies pectinata)

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    <p>Abstract</p> <p>Background</p> <p>Preparations of mistletoe (<it>Viscum album</it>) are the form of cancer treatment that is most frequently used in the complementary medicine. Previous work has shown that these preparations are able to exert cytotoxic effects on carcinoma cells, the extent of which might be influenced by the host tree species and by the content of mistletoe lectin.</p> <p>Methods</p> <p>Using colorimetric assays, we have now compared the cytotoxic effects of <it>Viscum album </it>preparations (VAPs) obtained from mistletoe growing on oak (<it>Quercus robur </it>and <it>Q. petraea</it>, VAP-Qu), apple tree (<it>Malus domestica</it>,, VAP-M), pine (<it>Pinus sylvestris</it>, VAP-P) or white fir (<it>Abies pectinata</it>, VAP-A), on the <it>in vitro </it>growth of breast and bladder carcinoma cell lines. While MFM-223, KPL-1, MCF-7 and HCC-1937 were the breast carcinoma cell lines chosen, the panel of tested bladder carcinoma cells comprised the T-24, TCC-SUP, UM-UC-3 and J-82 cell lines.</p> <p>Results</p> <p>Each of the VAPs inhibited cell growth, but the extent of this inhibition differed with the preparation and with the cell line. The concentrations of VAP-Qu, VAP-M and VAP-A which led to a 50 % reduction of cell growth (IC<sub>50</sub>) varied between 0.6 and 0.03 mg/ml. Higher concentrations of VAP-P were required to obtain a comparable effect. Purified mistletoe lectin I (MLI) led to an inhibition of breast carcinoma cell growth at concentrations lower than those of VAPs, but the sensitivity towards purified MLI did not parallel that towards VAPs. Bladder carcinoma cells were in most cases more sensitive to VAPs treatment than breast carcinoma cells. The total mistletoe lectin content was very high in VAP-Qu (54 ng/mg extract), intermediate in VAP-M (25 ng/mg extract), and very low in VAP-P (1.3 ng/mg extract) and in VAP-A (1 ng/mg extract). As to be expected from the low content of mistletoe lectin, VAP-P led to relatively weak cytotoxic effects. Most remarkably, however, the lectin-poor VAP-A revealed a cytotoxic effect comparable to, or even stronger than, that of the lectin-rich VAP-Qu, on all tested bladder and breast carcinoma cell lines.</p> <p>Conclusion</p> <p>The results suggest the existence of cytotoxic components other than mistletoe lectin in VAP-A and reveal an unexpected potential of this preparation for the treatment of breast and bladder cancer.</p

    The genomes of two key bumblebee species with primitive eusocial organization

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    Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation

    Platinum–rhodium–tin/carbon electrocatalysts for ethanol oxidation in acid media: effect of the precursor addition order and the amount of tin

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    Carbon-supported Pt x –Rh y –Sn z catalysts (x:y:z = 3:1:4, 6:2:4, 9:3:4) are prepared by Pt, Rh, and Sn precursors reduction in different addition order. The materials are characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy techniques and are evaluated for the electrooxidation of ethanol in acidic media by cyclic voltammetry, chronoamperometry, and anode potentiostatic polarization. The influence of both the order in which the precursors are added and the composition of metals in the catalysts on the electrocatalytic activity and physico-chemical characteristics of Pt x –Rh y –Sn z /C catalysts is evaluated. Oxidized Rh species prevail on the surface of catalysts synthesized by simultaneous co-precipitation, thus demonstrating the influence of synthesis method on the oxidation state of catalysts. Furthermore, high amounts of Sn in composites synthesized by co-precipitation result in very active catalysts at low potentials (bifunctional effect), while medium Sn load is needed for sequentially deposited catalysts when the electronic effect is most important (high potentials), since more exposed Pt and Rh sites are needed on the catalyst surface to alcohol oxidation. The Pt3–Rh1–Sn4/C catalyst prepared by co-precipitation is the most active at potentials lower than 0.55 V (related to bifunctional effect), while the Pt6–Rh2–Sn4/C catalyst, prepared by sequential precipitation (first Rh and, after drying, Pt + Sn), is the most active above 0.55 V.The authors thank the Brazilian National Council of Technological and Scientific Development-CNPq (Grants: 402243/2012-9, 303630/2012-4, 474261/2013-1, 407274/2013-8, and 310282/2013-6) for the scholarships and financial support for this work

    Reacquisition of the lower temporal bar in sexually dimorphic fossil lizards provides a rare case of convergent evolution

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    Temporal fenestration has long been considered a key character to understand relationships amongst reptiles. In particular, the absence of the lower temporal bar (LTB) is considered one of the defining features of squamates (lizards and snakes). In a re-assessment of the borioteiioid lizard Polyglyphanodon sternbergi (Cretaceous, North America), we detected a heretofore unrecognized ontogenetic series, sexual dimorphism (a rare instance for Mesozoic reptiles), and a complete LTB, a feature only recently recognized for another borioteiioid, Tianyusaurus zhengi (Cretaceous, China). A new phylogenetic analysis (with updates on a quarter of the scorings for P. sternbergi) indicates not only that the LTB was reacquired in squamates, but it happened independently at least twice. An analysis of the functional significance of the LTB using proxies indicates that, unlike for T. zhengi, this structure had no apparent functional advantage in P. sternbergi, and it is better explained as the result of structural constraint release. The observed canalization against a LTB in squamates was broken at some point in the evolution of borioteiioids, whereas never re-occuring in other squamate lineages. This case of convergent evolution involves a mix of both adaptationist and structuralist causes, which is unusual for both living and extinct vertebrates

    Exploiting solar visible-range observations by inversion techniques: from flows in the solar subsurface to a flaring atmosphere

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    Observations of the Sun in the visible spectral range belong to standard measurements obtained by instruments both on the ground and in the space. Nowadays, both nearly continuous full-disc observations with medium resolution and dedicated campaigns of high spatial, spectral and/or temporal resolution constitute a holy grail for studies that can capture (both) the long- and short-term changes in the dynamics and energetics of the solar atmosphere. Observations of photospheric spectral lines allow us to estimate not only the intensity at small regions, but also various derived data products, such as the Doppler velocity and/or the components of the magnetic field vector. We show that these measurements contain not only direct information about the dynamics of solar plasmas at the surface of the Sun but also imprints of regions below and above it. Here, we discuss two examples: First, the local time-distance helioseismology as a tool for plasma dynamic diagnostics in the near subsurface and second, the determination of the solar atmosphere structure during flares. The methodology in both cases involves the technique of inverse modelling.Comment: 29 pages, 15 figures. Accepted for publication in the book "Reviews in Frontiers of Modern Astrophysics: From Space Debris to Cosmology" (eds Kabath, Jones and Skarka; publisher Springer Nature) funded by the European Union Erasmus+ Strategic Partnership grant "Per Aspera Ad Astra Simul" 2017-1-CZ01-KA203-03556
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