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Tentacles of the sea anemone, Nematostella vectensis, are covered with hair bundles. Hair bundles were deflected by water jets to test whether they are mechanoreceptors. Electrophysiological
recordings confirm that deflections of hair bundles induce transients in membrane current. In a different species of anemone,
hair bundle mechanoreceptors are known to change shape and responsiveness according to the activity of chemoreceptors that
bind prey-derived compounds including N-acetylated sugars. In Nematostella, hair bundles significantly elongate upon exposure to NANA, an N-acetylated sugar. Based on a bioassay in which discharged nematocysts are counted in gelatin-coated test probes touched to
tentacles, we find that NANA shifts vibration dependent discharge of basitrich nematocysts to lower frequencies overlapping
those produced during swimming by known prey including planktonic crustaceans. Furthermore, we find for the first time that
vibration detection extends at least 2.5 cm beyond the tentacle tips. Thus, Nematostella likely employs its hair bundles to detect swimming movements of nearby prey. 相似文献
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José Carlos Parada-Fabián Patricia Juárez-García Iván Natividad-Bonifacio Carlos Vázquez-Salinas Elsa Irma Quiñones-Ramírez 《Food and environmental virology》2016,8(3):215-220
Foodborne viruses are a common and, probably, the most under-recognized cause of outbreaks of gastroenteritis. Among the main foods involved in the transmission of human enteric viruses are mollusks, and fruits and vegetables irrigated with wastewater and/or washed with non-potable water or contaminated by contact with surfaces or hands of the infected personnel during its preparation. In this study, 134 food samples were analyzed for the detection of Norovirus, Rotavirus, and Hepatitis A virus (HAV) by amplification of conserved regions of these viruses. From the 134 analyzed samples, 14 were positive for HAV, 6 for Norovirus, and 11 for Rotavirus. This is the first report in Mexico where emphasis is given to the presence of HAV and Norovirus on perishable foods and food from fisheries, as well as Rotavirus on frozen vegetables, confirming the role of vegetables and bivalve mollusks as transmitting vehicles of enteric viruses. 相似文献
457.
Anna Höglhammer Andreas Muhar Patricia Stokowski Thomas Schauppenlehner Renate Eder 《Local Environment》2018,23(8):814-829
Urban public spaces are important areas for leisure, recreation and physical activity and therefore contribute to the quality of life in cities. In particular, for adolescents they provide important spaces to meet with their peers, away from parental or school control. In many cities worldwide, public spaces have undergone severe developmental processes, and often a withdrawal from public space is noted. With regard to the opportunities those spaces provide for adolescents, it is necessary to investigate their current meaning for adolescents in a leisure context. In this article, qualitative research methods were used to investigate factors affecting adolescents’ use of public spaces in Vienna, Austria. In total 45 adolescents were interviewed. Results show that public open spaces are not regarded as important leisure spaces, and data reveal a strong retreat to private areas for leisure purposes. Perceived insecurities and fears support these processes and often result in avoidance of public spaces but also the wish for more control by authorities. 相似文献
458.
Erich M. G. Fitzgerald Matthew T. Carrano Timothy Holland Barbara E. Wagstaff David Pickering Thomas H. Rich Patricia Vickers-Rich 《Die Naturwissenschaften》2012,99(5):397-405
The basal theropod dinosaur clade Ceratosauria, and its subclade Abelisauroidea, is characteristic of late Mesozoic terrestrial vertebrate faunas in western Gondwana (South America, Africa, Madagascar, and India) and Europe. Yet unambiguous records of ceratosaurs have hitherto been absent from Australia, where the theropod assemblage appears to include several typically Laurasian clades. Here, we report the first evidence of ceratosaurs (and potentially abelisauroids) from eastern Gondwana––a diagnostic astragalocalcaneum from the Aptian (121–125?Ma) of Victoria, Australia. Ceratosauria thus occurred in both western and eastern Gondwana during the Early Cretaceous. This fossil adds to the poorly known dinosaur fauna of Australia, a major clade of basal theropods, emphasising that its mid-Cretaceous theropod diversity was surprisingly cosmopolitan despite relative geographic isolation, including clades that have been thought to be typical of both Gondwana and Laurasia––Ceratosauria, Spinosauridae, Carcharodontosauria, Tyrannosauroidea, and Deinonychosauria. Such a contemporaneous association of theropod clades is unknown from other Gondwanan continents and questions the views that the late Mesozoic dinosaur fauna of Australia was dominated by Gondwanan or Laurasian elements, extreme isolation, relictualism, and/or novelty as a ‘centre of origin’. The cosmopolitan theropod fauna of Australia probably reflects the global distribution of these clades early in their history, prior to significant continental breakup. 相似文献
459.
The discrimination of infectious and inactivated viruses remains a key obstacle when using quantitative RT-PCR (RT-qPCR) to
quantify enteric viruses. In this study, propidium monoazide (PMA) and RNase pretreatments were evaluated for the detection
and quantification of infectious hepatitis A virus (HAV). For thermally inactivated HAV, PMA treatment was more effective
than RNase treatment for differentiating infectious and inactivated viruses, with HAV titers reduced by more than 2.4 log10 units. Results showed that combining 50 μM of PMA and RT-qPCR selectively quantify infectious HAV in media suspensions. Therefore,
PMA treatment previous to RT-qPCR detection is a promising alternative to assess HAV infectivity. 相似文献
460.
Patricia Miretzky Carolina Mu?oz Enrique Cantoral-Uriza 《Environmental Chemistry Letters》2011,9(1):55-63
Naturally occurring diatomaceous earth was modified by alkaline pretreatment, and its effectiveness for Cd2+ removal from contaminated water was investigated. Batch experiments were carried out to determine Cd2+ adsorption capacity and the efficiency of the sorption process under different experimental conditions. Experimental data
showed good fitting to Langmuir and Freundlich isotherms models. The Cd2+ maximum adsorption capacity was 0.058 mmol g−1 for raw diatomite and increased to 0.195 mmol g−1 for alkaline-pretreated diatomite with efficiency higher than 96% (diatomite dose 2.5 g L−1, pH 6). Adsorption of Cd2+ to alkaline-pretreated diatomite increased as the temperature increased. Thermodynamic parameters were calculated to evaluate
the feasibility of the adsorption process at different temperatures. The adsorption process was spontaneous and endothermic.
The interaction between Cd2+ ions and diatomite surface was weak enough to be considered as physical sorption, confirmed by the low value of activation
energy. 相似文献