Desiccation tolerance and cryopreservation of seeds of black poplar (Populus nigra L.), a disappearing tree species in Europe     

Marcin Michalak  Beata P. Plitta  Tadeusz Tylkowski  Paweł Chmielarz  Jan Suszka 《European Journal of Forest Research》2015,134(1):53-60

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A cost of long-term memory in Drosophila     

Mery F  Kawecki TJ 《Science (New York, N.Y.)》2005,308(5725):1148

Two distinct forms of consolidated associative memory are known in Drosophila: long-term memory and so-called anesthesia-resistant memory. Long-term memory is more stable, but unlike anesthesia-resistant memory, its formation requires protein synthesis. We show that flies induced to form long-term memory become more susceptible to extreme stress (such as desiccation). In contrast, induction of anesthesia-resistant memory had no detectable effect on desiccation resistance. This finding may help to explain why evolution has maintained anesthesia-resistant memory as another form of consolidated memory, distinct from long-term memory.  相似文献   

Laser-induced ferroelectric structural order in an organic charge-transfer crystal     

Collet E  Lemée-Cailleau MH  Buron-Le Cointe M  Cailleau H  Wulff M  Luty T  Koshihara SY  Meyer M  Toupet L  Rabiller P  Techert S 《Science (New York, N.Y.)》2003,300(5619):612-615

We report the direct observation by x-ray diffraction of a photoinduced paraelectric-to-ferroelectric structural phase transition using monochromatic 100-picosecond synchrotron pulses. It occurs in tetrathiafulvalene-p-chloranil, a charge-transfer molecular material in which electronic and structural changes are strongly coupled. An optical 300-femtosecond laser pulse switches the material from a neutral to an ionic state on a 500-picosecond time scale and, by virtue of intrinsic cooperativity, generates self-organized long-range structural order. The x-ray data indicate a macroscopic ferroelectric reorganization after the laser irradiation. Refinement of the structures before and after laser irradiation indicates structural changes at the molecular level.  相似文献   

Targeting of cyclic AMP degradation to beta 2-adrenergic receptors by beta-arrestins     

Perry SJ  Baillie GS  Kohout TA  McPhee I  Magiera MM  Ang KL  Miller WE  McLean AJ  Conti M  Houslay MD  Lefkowitz RJ 《Science (New York, N.Y.)》2002,298(5594):834-836

Catecholamines signal through the beta2-adrenergic receptor by promoting production of the second messenger adenosine 3',5'-monophosphate (cAMP). The magnitude of this signal is restricted by desensitization of the receptors through their binding to beta-arrestins and by cAMP degradation by phosphodiesterase (PDE) enzymes. We show that beta-arrestins coordinate both processes by recruiting PDEs to activated beta2-adrenergic receptors in the plasma membrane of mammalian cells. In doing so, the beta-arrestins limit activation of membrane-associated cAMP-activated protein kinase by simultaneously slowing the rate of cAMP production through receptor desensitization and increasing the rate of its degradation at the membrane.  相似文献   

Sequence variability, recombination analysis, and specific detection of the W strain of Plum pox virus     

Glasa M  Malinowski T  Predajňa L  Pupola N  Dekena D  Michalczuk L  Candresse T 《Phytopathology》2011,101(8):980-985

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Discrimination of lithogenic and anthropogenic influences on topsoil magnetic susceptibility in Central Europe   总被引：12，自引：0，他引：12  

T. Magiera  Z. Strzyszcz  A. Kapicka  E. Petrovsky  EU RTD Project No. EVK-CT-- MAGPROX TEAM 《Geoderma》2006,130(3-4):299-311

The study was performed on the area of the three countries involved in the MAGPROX project (Poland, Czech Rep., Germany). In the first stage the basic map of magnetic susceptibility based on the field topsoil measurement was compiled with an average grid density of 10 km. In the second stage of the study, vertical distribution of magnetic susceptibility of ca. 600 topsoil cores (0.3 m long), collected over central Europe, was examined with respect to the anthropogenic or lithogenic influence on magnetic susceptibility of the soil surface, with the focus being on the interpretation of the areas showing high surface susceptibility values. The maximum values were mostly observed in depths of 3–4 cm. In general seven different types of susceptibility profiles from forest areas and one typical for urban soil are presented. They are a result of a combination of natural (litho- and pedogenic) and anthropogenic contributions. Our results prove that soil profiles, dominated by anthropogenic influence due to atmospherically deposited dust, are characterized by magnetically enhanced humuous layer, corresponding to layer with the highest concentration of heavy metals. Moreover, forest soils show in these cases higher magnetic susceptibility than soils in open areas (grassland, meadows or arable soils).  相似文献   

Crystal structure of the rabies virus nucleoprotein-RNA complex     

Albertini AA  Wernimont AK  Muziol T  Ravelli RB  Clapier CR  Schoehn G  Weissenhorn W  Ruigrok RW 《Science (New York, N.Y.)》2006,313(5785):360-363

Negative-strand RNA viruses condense their genome into a helical nucleoprotein-RNA complex, the nucleocapsid, which is packed into virions and serves as a template for the RNA-dependent RNA polymerase complex. The crystal structure of a recombinant rabies virus nucleoprotein-RNA complex, organized in an undecameric ring, has been determined at 3.5 angstrom resolution. Polymerization of the nucleoprotein is achieved by domain exchange between protomers, with flexible hinges allowing nucleocapsid formation. The two core domains of the nucleoprotein clamp around the RNA at their interface and shield it from the environment. RNA sequestering by nucleoproteins is likely a common mechanism used by negative-strand RNA viruses to protect their genomes from the innate immune response directed against viral RNA in human host cells at certain stages of an infectious cycle.  相似文献   

Glochidial infestation of fish by the endangered thick‐shelled river mussel Unio crassus          下载免费PDF全文

Adam M. Ćmiel  Katarzyna Zając  Anna M. Lipińska  Tadeusz Zając 《水产资源保护:海洋与淡水生态系统》2018,28(3):535-544

Toward a Cost-Efficient Method for Monitoring of Traffic-Derived Pollutants with Quartz Sand Boxes     

Gobinda Ojha  Erwin Appel  Małgorzata Wawer  Tadeusz Magiera  Shouyun Hu 《Water, air, and soil pollution》2016,227(6):173

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Feline leukaemia. ABCD guidelines on prevention and management     

Hans Lutz  Diane Addie  Sándor Belák  Corine Boucraut-Baralon  Herman Egberink  Tadeusz Frymus  Tim Gruffydd-Jones  Katrin Hartmann  Margaret J. Hosie  Albert Lloret  Fulvio Marsilio  Maria Grazia Pennisi  Alan D. Radford  Etienne Thiry  Uwe Truyen  Marian C. Horzinek 《Journal of Feline Medicine and Surgery》2009,11(7):565-574

OverviewFeline leukaemia virus (FeLV) is a retrovirus that may induce depression of the immune system, anaemia and/or lymphoma. Over the past 25 years, the prevalence of FeLV infection has decreased considerably, thanks both to reliable tests for the identification of viraemic carriers and to effective vaccines.InfectionTransmission between cats occurs mainly through friendly contacts, but also through biting. In large groups of non-vaccinated cats, around 30–40% will develop persistent viraemia, 30–40% show transient viraemia and 20–30% seroconvert. Young kittens are especially susceptible to FeLV infection.Disease signsThe most common signs of persistent FeLV viraemia are immune suppression, anaemia and lymphoma. Less common signs are immune-mediated disease, chronic enteritis, reproductive disorders and peripheral neuropathies. Most persistently viraemic cats die within 2–3 years.DiagnosisIn low-prevalence areas there may be a risk of false-positive results; a doubtful positive test result in a healthy cat should therefore be confirmed, preferably by PCR for provirus. Asymptomatic FeLV-positive cats should be retested.Disease managementSupportive therapy and good nursing care are required. Secondary infections should be treated promptly. Cats infected with FeLV should remain indoors. Vaccination against common pathogens should be maintained. Inactivated vaccines are recommended. The virus does not survive for long outside the host.Vaccination recommendationsAll cats with an uncertain FeLV status should be tested prior to vaccination. All healthy cats at potential risk of exposure should be vaccinated against FeLV. Kittens should be vaccinated at 8–9 weeks of age, with a second vaccination at 12 weeks, followed by a booster 1 year later. The ABCD suggests that, in cats older than 3–4 years of age, a booster every 2–3 years suffices, in view of the significantly lower susceptibility of older cats.  相似文献