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The JmjC-containing lysine demethylase, KDM4D, demethylates di-and tri-methylation of histone H3 on lysine 9 (H3K9me3). How KDM4D is recruited to chromatin and recognizes its histone substrates remains unknown. Here, we show that KDM4D binds RNA independently of its demethylase activity. We mapped two non-canonical RNA binding domains: the first is within the N-terminal spanning amino acids 115 to 236, and the second is within the C-terminal spanning amino acids 348 to 523 of KDM4D. We also demonstrate that RNA interactions with KDM4D N-terminal region are critical for its association with chromatin and subsequently for demethylating H3K9me3 in cells. This study implicates, for the first time, RNA molecules in regulating the levels of H3K9 methylation by affecting KDM4D association with chromatin.  相似文献   
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The parasitoid wasp Ampulex compressa stings and injects venom into the cockroach brain to induce a long-lasting hypokinetic state. This state is characterized by decreased responsiveness to aversive stimuli, suggesting the manipulation of a neuromodulatory system in the cockroach’s central nervous system. A likely candidate is the opioid system, which is known to affect responsiveness to stimuli in insects. To explore this possibility, we injected cockroaches with different opioid receptor agonists or antagonists before they were stung by a wasp and tested the escape behavior of these cockroaches to electric foot shocks. Antagonists significantly decreased the startle threshold in stung individuals, whereas agonists led to an increased startle threshold in controls. Yet, neither agonists nor antagonists had any effect on grooming. To further characterize the interaction between the venom and opioid receptors, we used an antenna-heart preparation. In un-stung individuals external application of crude venom completely inhibits antenna-heart contractions. In stung individuals the antenna-heart showed no contractions. Although acetylcholine restored contractions, the opioid receptor antagonist naloxone was unable to antagonize the venom inhibition. These results suggest that the venom of A. compressa might contribute to the manipulation of cockroach behavior by affecting the opioid system.  相似文献   
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Most plant communities support a diverse assemblage of arbuscular mycorrhizal fungi (AMF). AMF communities have the potential to affect plant community structure and vice versa. We examined AMF sporulation in a 4.5‐ha reconstructed prairie in Eau Claire County, Wisconsin. In fall 2003, the site was planted with varied numbers and combinations of native prairie species from four functional guilds: C3 grasses/sedges, C4 grasses, legume, and nonleguminous forbs. We hypothesized that more diverse plant seeding mixtures would promote AMF diversity. To examine the interaction between plant and fungal communities, plots were divided and subplots treated with the fungicide chlorothalonil to suppress AMF, enriched with ammonium nitrate fertilizer, treated with both fungicide and nitrogen, or remained untreated (control). Soil samples were collected during the summers of 2004, 2006, and 2007 from each subplot. Spores of AMF were extracted, identified to species, and enumerated. Initial plant seeding diversity did not significantly influence spore abundance, fungal diversity, plant productivity, or plant richness 4 years after establishment. Fungal species richness was positively, but weakly, correlated with plant productivity (r2 = 0.11) and plant richness (r2 = 0.09). Fungal community composition changed significantly over time; nitrogen addition, fungicide application, and site characteristics also shaped community composition. After 4 years of treatment, nitrogen and fungicide reduced AMF richness, changed sporulation patterns among AMF taxa, and reduced diversity and productivity in plant communities. Divergence in AMF community is being mirrored by changes in the plant community independent of initial seeding treatments, though causation could not be determined.  相似文献   
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The red list has become a ubiquitous tool in the conservation of species. We analyzed contemporary trends in the threat levels of European orchids, in total 166 species characterized in 27 national red lists, in relation to their reproductive biology and growth form, distribution area, and land cover where they occur. We found that species in central Europe are more threatened than those in the northern, southern, or Atlantic parts of Europe, while species were least threatened in southern Europe. Nectarless and tuberous species are significantly more threatened than nectariferous and rhizomatous taxa. Land cover (ratios of artificial land cover, area of pastures and grasslands, forests and inland wetlands) also significantly impacted the threat level. A bigger share of artificial land cover increases threat, and a bigger share of pasture and grassland lowers it. Unexpectedly, a bigger share of inland wetland area in a country increased threat level, which we believe may be due to the threatened nature of wetlands themselves relative to other natural land cover types. Finally, species occurring in multiple countries are on average less threatened. We believe that large‐scale analysis of current IUCN national red lists as based on their specific categories and criteria may particularly inform the development of coordinated regional or larger‐scale management strategies. In this case, we advocate for a coordinated EU protection and restoration strategy particularly aimed at central European orchids and those occurring in wetland area.  相似文献   
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When predicting financial profits [1], relationship outcomes [2], longevity [3], or professional success [4], people habitually underestimate the likelihood of future negative events (for review see [5]). This well-known bias, termed unrealistic optimism [6], is observed across age [7], culture [8], and species [9] and has a significant societal impact on domains ranging from financial markets to health and well being. However, it is unknown how neuromodulatory systems impact on the generation of optimistically biased beliefs. This question assumes great importance in light of evidence that common neuropsychiatric disorders, such as depression, are characterized by pessimism [10, 11]. Here, we show that administration of a drug that enhances dopaminergic function (dihydroxy-L-phenylalanine; L-DOPA) increases an optimism bias. This effect is due to L-DOPA impairing the ability to update belief in response to undesirable information about the future. These findings provide the?first evidence that the neuromodulator dopamine impacts on belief formation by reducing negative expectations regarding the future.  相似文献   
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Because the stress protein GRP94 can augment presentation of peptides to T cells, it is important to define how it, as well as all other HSP90 family members, binds peptides. Having previously shown that the N-terminal half of GRP94 can account for the peptide binding activity of the full-length protein, we now locate this binding site by testing predictions of a molecular docking model. The best predicted site was on the opposite face of the beta sheet from the pan-HSP90 radicicol-binding pocket, in close proximity to a deep hydrophobic pocket. The peptide and radicicol-binding sites are distinct, as shown by the ability of a radicicol-refractive mutant to bind peptide. When the fluorophore acrylodan is attached to Cys117 within the hydrophobic pocket, its fluorescence is reduced upon peptide binding, consistent with proximity of the two ligands. Substitution of His125, which contacts the bound peptide, compromises peptide-binding activity. We conclude that peptide binds to the concave face of the beta sheet of the N-terminal domain, where binding is regulated during the action cycle of the chaperone.  相似文献   
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