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941.
942.
Jordan Guiz Anne Ebeling Nico Eisenhauer Nina Hacker Lionel Hertzog Yvonne Oelmann Christiane Roscher Cameron Wagg Helmut Hillebrand 《Oikos》2018,127(7):903-914
The extensive use of traits in ecological studies over the last few decades to predict community functions has revealed that plant traits are plastic and respond to various environmental factors. These plant traits are assumed to predict how plants compete and capture resources. Variation in stoichiometric ratios both within and across species reflects resource capture dynamics under competition. However, the impact of local plant diversity on species‐specific stoichiometry remains poorly studied. Here, we analyze how spatial and temporal diversity in resource‐acquisition traits affects leaf elemental stoichiometry of plants (i.e. the result of resource capture) and how flexible this stoichiometry is depending on the functional composition of the surrounding community. Therefore, we assessed inter‐ and intraspecific variations of leaf carbon (C), nitrogen (N), and phosphorus (P) (and their ratios) of 20 grassland species in a large trait‐based plant diversity experiment located in Jena (Germany) by measuring leaf elemental concentrations at the species‐level along a gradient in plant trait dissimilarity. Our results show that plants showed large intra‐ and interspecific variation in leaf stoichiometry, which was only partly explained by the functional group identity (grass or herb) of the species. Elemental concentrations (N, P, but not C) decreased with plant species richness, and species tended to become more deviant from their monoculture stoichiometry with increasing trait dissimilarity in the community. These responses differed among species, some consistently increased or decreased in P and N concentrations; for other species, the negative or positive change in P and N concentrations increased with increasing trait difference between the target species and the remaining community. The strength of this relationship was significantly associated to the relative position of the species along trait gradients related to resource acquisition. Trait‐difference and trait‐diversity thus were important predictors of how species’ resource capture changed in competitive neighbourhoods. 相似文献
943.
Trait means,trait plasticity and trait differences to other species jointly explain species performances in grasslands of varying diversity 下载免费PDF全文
Christiane Roscher Marlén Gubsch Annett Lipowsky Jens Schumacher Alexandra Weigelt Nina Buchmann Ernst‐Detlef Schulze Bernhard Schmid 《Oikos》2018,127(6):865-865
Functional traits may help to explain the great variety of species performances in plant communities, but it is not clear whether the magnitude of trait values of a focal species or trait differences to co‐occurring species are key for trait‐based predictions. In addition, trait expression within species is often plastic, but this variation has been widely neglected in trait‐based analyses. We studied functional traits and plant biomass of 59 species in 66 experimental grassland mixtures of varying species richness (Jena Experiment). We related mean species performances (species biomass and relative yield RY) and their plasticities along the diversity gradient to trait‐based pedictors involving mean species traits (Tmean), trait plasticities along the diversity gradient (Tslope), extents of trait variation across communities (TCV; coefficient of variation) and hierarchical differences (Tdiff) and trait distances (absolute values of trait differences Tdist) between focal and co‐occurring species. Tmean (30–55%) and Tdiff (30–33%) explained most variation in mean species performances and their plasticities, but Tslope (20–25%) was also important in explaining mean species performances. The mean species traits and the trait differences between focal species and neighbors with the greatest explanatory power were related to plant size and stature (shoot length, mass:height ratios) and leaf photosynthetic capacity (specific leaf area, stable carbon isotopes and leaf nitrogen concentration). The contribution of trait plasticities in explaining species performances varied in direction (positive or negative) and involved traits related to photosynthetic capacity, nitrogen acquisition (nitrogen concentrations and stable isotopes) as well as structural stability (shoot carbon concentrations). Our results suggest that incorporating plasticity in trait expression as well as trait differences to co‐occurring species is critical for extending trait‐based analyses to understand the assembly of plant communities and the contribution of individual species in structuring plant communities. 相似文献
944.
945.
Carsten Slotta Jonathan Storm Nina Pfisterer Elena Henkel Svenja Kleinwächter Maren Pieper Lucia M. Ruiz-Perera Johannes F.W. Greiner Barbara Kaltschmidt Christian Kaltschmidt 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》2018,1865(8):1025-1033
TNF signaling is directly linked to cancer development and progression. A broad range of tumor cells is able to evade cell death induced by TNF impairing the potential anti-cancer value of TNF in therapy. Although sensitizing cells to TNF-induced death therefore has great clinical implications, detailed mechanistic insights into TNF-mediated human cell death still remain unknown. Here, we analyzed human cells by applying CRISPR/Cas9n to generate cells deficient of IKK1, IKK2, IKK1/2 and RELA. Despite stimulation with TNF resulted in impaired NF-κB activation in all genotypes compared to wildtype cells, increased cell death was observable only in IKK1/2-double-deficient cells. Cell death could be detected by Caspase-3 activation and binding of Annexin V. TNF-induced programmed cell death in IKK1/2?/? cells was further shown to be mediated via RIPK1 in a predominantly apoptotic manner. Our findings demonstrate the IKK complex to protect from TNF-induced cell death in human cells independently to NF-κB RelA suggesting IKK1/2 to be highly promising targets for cancer therapy. 相似文献
946.
Caroline Vianna Velasco Castilho Jaime Fidalgo Ferra Neto Suzana Guimarães Leitão Carolina Santos Barreto Shaft Corrêa Pinto Nina Claudia Barboza da Silva 《Plant Cell, Tissue and Organ Culture》2018,133(3):311-323
Anemia tomentosa var. anthriscifolia is an aromatic fern with a pleasant woody aroma and antimycobacterial activity. In this paper, we describe for the first time its spore-derived gametophyte development and the effect of indole-3-acetic acid and jasmonic acid on in vitro gametophyte/sporophyte development, as well as volatile compound production. Volatiles were obtained by simultaneous distillation and extraction (SDE) and analyzed by high resolution gas chromatography coupled with mass spectrometry. Spore-derived gametophytes were able to develop into sporophytes independently of the media culture composition, even when no plant growth regulator was added. Fifty different substances were detected in all in vitro A. tomentosa SDE extracts, while 20 were detected in the wild SDE plant extract. Monoterpenes were more prevalent (69.8–89.8%) than sesquiterpenes (9.4–28.7%) in in vitro plants, while sesquiterpenes represent 97.5% of the volatiles produced by the wild-grown plants. The major monoterpene components in in vitro plants were α-pinene (9.3–24.3%), trans-pinocarveol (20.6–27.9%), pinocarvone (15.4–25.1%) and myrtenyl acetate (6.4–12.3%). The triquinane sesquiterpenes silphiperfol-6-ene (0.6–2.9%), α-guaiene (0.5–2.5%), β-barbatene (1.1–3.9%) and 9-epi-presilphiperfolan-1-ol (2.5–5.6%) represent the most abundant sesquiterpenes. The changes in the monoterpene/sesquiterpene rates between micropropagated and wild plants are not related to the presence of JA or IAA in the media culture. Further studies are still needed to obtain a complete understanding of the factors leading to these results, which could be related to differences in the irradiance levels of in vitro plants versus those from a wild environment, as well as the developmental stage of the plants. This is the first report of the use of plant growth regulators on Anemia tomentosa in vitro culture development and their effects on volatile profiles. 相似文献
947.
948.
WDR11‐mediated Hedgehog signalling defects underlie a new ciliopathy related to Kallmann syndrome 下载免费PDF全文
Yeon‐Joo Kim Daniel PS Osborn Ji‐Young Lee Masatake Araki Kimi Araki Timothy Mohun Johanna Känsäkoski Nina Brandstack Hyun‐Taek Kim Francesc Miralles Cheol‐Hee Kim Nigel A Brown Hyung‐Goo Kim Juan Pedro Martinez‐Barbera Paris Ataliotis Taneli Raivio Lawrence C Layman Soo‐Hyun Kim 《EMBO reports》2018,19(2):269-289
949.
V. K. Chernyshev V. P. Korchagin L. P. Babich O. M. Burenkov G. I. Volkov Yu. N. Dolin V. I. Dudin V. A. Ivanov A. V. Ivanovskiy G. V. Karpov A. I. Krayev V. B. Kudelkin I. V. Morozov S. V. Pak S. M. Polyushko A. N. Skobelev V. A. Tokarev R. R. Zubaerova 《Plasma Physics Reports》2018,44(2):180-189
The results of the last (in the thermonuclear program “Magnetic compression”) MAGO-IX experiment with a plasma chamber including a third compartment designed to compress plasma with a converging liner are presented. An X-ray pulse consisting of an intense peak of 1-μs duration, followed by a low-intensity tail with a duration of more than 10 μs, was recorded. In the MAGO-IX experiment, the neutrons were generated mainly in the third compartment. A neutron yield of 2 × 1012 was obtained. The results demonstrate that the expected compression of preheated plasma in chambers similar to MAGO-IX is promising for achieving thermonuclear ignition. 相似文献