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1.
The cyclic dinucleotides 3'‐5'diadenylate (c‐diAMP) and 3'‐5' diguanylate (c‐diGMP) are important bacterial second messengers that have recently been shown to stimulate the secretion of type I Interferons (IFN‐Is) through the c‐diGMP‐binding protein MPYS/STING. Here, we show that physiologically relevant levels of cyclic dinucleotides also stimulate a robust secretion of IL‐1β through the NLRP3 inflammasome. Intriguingly, this response is independent of MPYS/STING. Consistent with most NLRP3 inflammasome activators, the response to c‐diGMP is dependent on the mobilization of potassium and calcium ions. However, in contrast to other NLRP3 inflammasome activators, this response is not associated with significant changes in mitochondrial potential or the generation of mitochondrial reactive oxygen species. Thus, cyclic dinucleotides activate the NLRP3 inflammasome through a unique pathway that could have evolved to detect pervasive bacterial pathogen‐associated molecular patterns associated with intracellular infections.  相似文献   

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In Caenorhabditis briggsae hermaphrodites, spermatogenesis begins in the L4 larval stage and persists into early adulthood. Oogenesis begins after spermatogenesis; the sperm‐to‐oocyte transition is irreversible. The timing of this transition is believed to have evolved in response to selection to maximize the intrinsic growth rate. Sperm‐to‐oocyte transitions occurred early in Cbr‐met‐2 and Cbr‐fem‐3 mutants. These early transitions resulted in reduced brood sizes, but had little or no impact on the intrinsic growth rate. In Cbr‐met‐2; Cbr‐fem‐3 doubly mutant hermaphrodites, the transition to oogenesis occurred even earlier and brood size was further reduced, indicating that Cbr‐met‐2 and Cbr‐fem‐3 regulate the sperm‐to‐oocyte transition through separate pathways. Mutations in Cbr‐met‐2 also resulted in an increase in the frequency of males in mutant populations. These increased male frequencies were not caused by increased rates of X nondisjunction during oogenesis in mutant hermaphrodites. Rather, increases in the rates of outcrossing in mutant populations likely were an indirect effect of reduced brood sizes derived from self‐fertilization. Based on these observations, it is possible that the timing of the sperm‐to‐oocyte transition in C. briggsae evolved in response to sexual selection on hermaphrodites to limit rates of outcrossing. Mutations in the orthologous Caenorhabditis elegans gene, Cel‐met‐2, did not impact the timing of the sperm‐to‐oocyte transition, consistent with the independent evolution of hermaphroditic reproduction in these species. Although brood sizes were reduced in Cel‐met‐2 mutant strains, increased male frequencies were not observed. Cbr‐ and Cel‐met‐2 mutations also differed in terms of germline mortality, observed in C. elegans, but not in C. briggsae.  相似文献   

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5‐Methyl‐4‐methylidene‐6‐(trimethylsilyl)hexanal ( 1b ), a sila analog of the acyclic lily‐of‐the‐valley odorant 5,7,7‐trimethyl‐4‐methylideneoctanal ( 1a ), and the Si‐containing derivatives 2 – 6 were prepared in multistep syntheses, starting from Cl3SiH and Cl2SiMe2, respectively. Compounds 1b, 2 – 6 , and their new precursors were characterized by elemental analyses (C, H, N) and NMR spectroscopic studies (1H, 13C, 15N, and 29Si). To gain more information about the structure? odor correlation in the family of lily‐of‐the‐valley or ‘muguet’ odorants, C/Si analogs 1a / 1b and derivatives 2 – 6 were evaluated for their olfactory properties.  相似文献   

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《Chirality》2017,29(1):33-37
Dehydrative cyclization of 4‐(D‐altro ‐pentitol‐1‐yl)2‐phenyl‐2H ‐1,2,3‐triazole in basic medium with one moler equivalent of p‐toluene sulfonyl chloride in pyridine solution gave the homo‐C‐ nucleoside 4‐(2,5‐anhydro‐D‐altro ‐1‐yl)‐2‐phenyl‐2H ‐1,2,3‐triazole. The structure and anomeric configuration was determined by acylation, nuclear magnetic resonance (NMR), and mass spectroscopy. The stereochemistry at the carbon bridge of homo‐C‐ nucleoside 2‐phenyl‐2H ‐1,2,3‐triazoles was determined by circular dichroism (CD) spectroscopy.  相似文献   

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The COVID‐2019 pandemic is the most severe acute public health threat of the twenty‐first century. To properly address this crisis with both robust testing and novel treatments, we require a deep understanding of the life cycle of the causative agent, the SARS‐CoV‐2 coronavirus. Here, we examine the architecture and self‐assembly properties of the SARS‐CoV‐2 nucleocapsid protein, which packages viral RNA into new virions. We determined a 1.4 Å resolution crystal structure of this protein's N2b domain, revealing a compact, intertwined dimer similar to that of related coronaviruses including SARS‐CoV. While the N2b domain forms a dimer in solution, addition of the C‐terminal spacer B/N3 domain mediates formation of a homotetramer. Using hydrogen‐deuterium exchange mass spectrometry, we find evidence that at least part of this putatively disordered domain is structured, potentially forming an α‐helix that self‐associates and cooperates with the N2b domain to mediate tetramer formation. Finally, we map the locations of amino acid substitutions in the N protein from over 38,000 SARS‐CoV‐2 genome sequences. We find that these substitutions are strongly clustered in the protein's N2a linker domain, and that substitutions within the N1b and N2b domains cluster away from their functional RNA binding and dimerization interfaces. Overall, this work reveals the architecture and self‐assembly properties of a key protein in the SARS‐CoV‐2 life cycle, with implications for both drug design and antibody‐based testing.  相似文献   

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This article takes its starting‐point from an elderly Bardi woman's observation that elders ‘used to frighten’ younger generations with stories about various spirit beings. The beings she referred to are a group of malevolent beings inhabiting particular locations in her country, located in the northwest Kimberley region of Western Australia. Beginning with her observation that this is something that ‘used’ to happen, I consider the relationship between persons and different kinds of spirit beings amidst historical impetus for change. Political, economic, ecological, technological, and other impacts have occurred within the shifting context of progressive engagements with Western colonialism, capitalism, and the market economy, with implications for local ontologies. I suggest that these spirit beings are becoming less differentiated and consider the implications of this in terms of personhood and the constitution of the social, arguing that the disappearance of some of these beings is suggestive of a contraction of temporal and spatial extensions of personhood, with implications for relations with country.  相似文献   

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Two new α‐pyrones (=2H‐pyran‐2‐ones), ficipyrones A and B ( 1 and 2 , resp.), and two new α‐furanones (=2H‐furan‐2‐ones), ficifuranones A and B ( 3 and 4 , resp.), together with three known metabolites, antibiotic F 0368 ( 5 ), hydroxyseiridin ( 6 ), and hydroxyisoseiridin ( 7 ), were isolated from solid cultures of the plant endophytic fungus Pestalotiopsis fici. Their structures were elucidated primarily by NMR spectroscopy, and the absolute configuration of 1 was deduced from the circular‐dichroism (CD) data. Compound 1 showed antifungal activity against the plant pathogen Gibberella zeae (CGMCC 3.2873) with an IC50 value of 15.9 μM .  相似文献   

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Virus‐infected plants show strong morphological and physiological alterations. Many physiological processes in chloroplast are affected, including the plastidic isoprenoid biosynthetic pathway [the 2C‐methyl‐D‐erythritol‐4‐phosphate (MEP) pathway]; indeed, isoprenoid contents have been demonstrated to be altered in virus‐infected plants. In this study, we found that the levels of photosynthetic pigments and abscisic acid (ABA) were altered in Potato virus Y (PVY)‐infected tobacco. Using yeast two‐hybrid assays, we demonstrated an interaction between virus protein PVY helper component‐proteinase (HC‐Pro) and tobacco chloroplast protein 1‐deoxy‐D‐xylulose‐5‐phosphate synthase (NtDXS). This interaction was confirmed using bimolecular fluorescence complementation (BiFC) assays and pull‐down assays. The Transket_pyr domain (residues 394–561) of NtDXS was required for interaction with HC‐Pro, while the N‐terminal region of HC‐Pro (residues 1–97) was necessary for interaction with NtDXS. Using in vitro enzyme activity assays, PVY HC‐Pro was found to promote the synthase activity of NtDXS. We observed increases in photosynthetic pigment contents and ABA levels in transgenic plants with HC‐Pro accumulating in the chloroplasts. During virus infection, the enhancement of plastidic isoprenoid biosynthesis was attributed to the enhancement of DXS activity by HC‐Pro. Our study reveals a new role of HC‐Pro in the host plant metabolic system and will contribute to the study of host–virus relationships.  相似文献   

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Since the future of anthropology in Australia is clouded, the address takes a look at where it has been coming from. Rather than a distinctive regional school, the discipline in Australia has been part of anthropology in the UK and the USA. In common with anthropology elsewhere, it lacks a distinctive theoretical stance, but draws on the theory current in the other social sciences. Recognising that what makes anthropology ‘special’ is the field work experience, the address reflects on the history and nature of this practice.  相似文献   

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In order to assign the absolute configurations of 8‐tert‐butyl‐2‐hydroxy‐7‐methoxy‐8‐methyl‐9‐oxa‐6‐azaspiro[4.5]dec‐6‐en‐10‐one ( 2a , 2b ), their esters ( 5a , 5b , 5c , 5d ) with (R)‐ or (S)‐2‐methoxyphenylacetic acid ( 4a , 4b ) have been synthesized. The absolute configurations of these compounds have been determined on the basis of NOESY correlations between the protons of the tert‐butyl group and the cyclopentane fragment of the molecules. The crucial part of this analysis was assignment of the absolute configuration at C‐5. Additionally, by calculation of the chemical shift anisotropy, δRS, for the relevant protons, it was also possible to confirm the absolute configurations at the C‐2 centres of compounds 2a , 2b and 5a , 5b , 5c , 5d . Chirality, 25:422–426, 2013.© 2013 Wiley Periodicals, Inc.  相似文献   

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The acetylcholinesterase inhibition by enantiomers of exo‐ and endo‐2‐norbornyl‐Nn‐butylcarbamates shows high stereoselelectivity. For the acetylcholinesterase inhibitions by (R)‐(+)‐ and (S)‐(?)‐exo‐2‐norbornyl‐Nn‐butylcarbamates, the R‐enantiomer is more potent than the S‐enantiomer. But, for the acetylcholinesterase inhibitions by (R)‐(+)‐ and (S)‐(?)‐endo‐2‐norbornyl‐Nn‐butylcarbamates, the S‐enantiomer is more potent than the R‐enantiomer. Optically pure (R)‐(+)‐exo‐, (S)‐(?)‐exo‐, (R)‐(+)‐endo‐, and (S)‐(?)‐endo‐2‐norbornyl‐Nn‐butylcarbamates are synthesized from condensations of optically pure (R)‐(+)‐exo‐, (S)‐(?)‐exo‐, (R)‐(+)‐endo‐, and (S)‐(?)‐endo‐2‐norborneols with n‐butyl isocyanate, respectively. Optically pure norborneols are obtained from kinetic resolutions of their racemic esters by lipase catalysis in organic solvent. Chirality 2010. © 2009 Wiley‐Liss, Inc.  相似文献   

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Although the concept of pathological grief dates back at least as far as Freud’s “Mourning and Melancholia”, there has been opposition to its recognition as a distinct mental disorder. Resistance has been overcome by evidence demonstrating that distinctive symptoms of prolonged grief disorder (PGD) – an attachment disturbance featuring yearning for the deceased, loss of meaning and identity disruption – can endure, prove distressing and disabling, and require targeted treatment. In acknowledgement of this evidence, the American Psychiatric Association Assembly has recently voted to include PGD as a new mental disorder in the DSM‐5‐TR. We tested the validity of the new DSM criteria for PGD and of an adapted version of our PG‐13 scale, the PG‐13‐Revised (PG‐13‐R), designed to map onto these criteria, using data from investigations conducted at Yale University (N=270), Utrecht University (N=163) and Oxford University (N=239). Baseline assessments were performed at 12‐24 months post‐loss; follow‐up assessments took place 5.3‐12.0 months later. Results indicated that the PG‐13‐R grief symptoms represent a unidimensional construct, with high degrees of internal consistency (Cronbach's alpha = 0.83, 0.90 and 0.93, for Yale, Utrecht and Oxford, respectively). The DSM PGD diagnosis was distinct from post‐traumatic stress disorder (phi=0.12), major depressive disorder (phi=0.25) and generalized anxiety disorder (phi=0.26) at baseline. Temporal stability was remarkable for this diagnosis (r=0.86, p<0.001). Kappa agreement between a PG‐13‐R threshold symptom summary score of 30 and the DSM symptom criterion for PGD was 0.70‐0.89 across the datasets. Both the DSM PGD diagnosis and the PG‐13‐R symptom summary score at baseline were significantly associated (p<0.05) with symptoms and diagnoses of major depressive disorder, post‐traumatic stress disorder and/or generalized anxiety disorder, suicidal ideation, worse quality of life and functional impairments at baseline and at follow‐up, in the Yale, Utrecht and Oxford datasets. Overall, the DSM‐5‐TR criteria for PGD and the PG‐13‐R both proved reliable and valid measures for the classification of bereaved individuals with maladaptive grief responses.  相似文献   

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Inverse‐probability‐of‐treatment weighted (IPTW) estimation has been widely used to consistently estimate the causal parameters in marginal structural models, with time‐dependent confounding effects adjusted for. Just like other causal inference methods, the validity of IPTW estimation typically requires the crucial condition that all variables are precisely measured. However, this condition, is often violated in practice due to various reasons. It has been well documented that ignoring measurement error often leads to biased inference results. In this paper, we consider the IPTW estimation of the causal parameters in marginal structural models in the presence of error‐contaminated and time‐dependent confounders. We explore several methods to correct for the effects of measurement error on the estimation of causal parameters. Numerical studies are reported to assess the finite sample performance of the proposed methods.  相似文献   

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With the rising demand for flexible and wearable electronic devices, flexible power sources with high energy densities are required to provide a sustainable energy supply. Theoretically, rechargeable, flexible Li‐O2/air batteries can provide extremely high specific energy densities; however, the high costs, complex synthetic methods, and inferior mechanical properties of the available flexible cathodes severely limit their practical applications. Herein, inspired by the structure of human blood capillary tissue, this study demonstrates for the first time the in situ growth of interpenetrative hierarchical N‐doped carbon nanotubes on the surface of stainless‐steel mesh (N‐CNTs@SS) for the fabrication of a self‐supporting, flexible electrode with excellent physicochemical properties via a facile and scalable one‐step strategy. Benefitting from the synergistic effects of the high electronic conductivity and stable 3D interconnected conductive network structure, the Li‐O2 batteries obtained with the N‐CNTs@SS cathode exhibit superior electrochemical performance, including a high specific capacity (9299 mA h g?1 at 500 mA g?1), an excellent rate capability, and an exceptional cycle stability (up to 232 cycles). Furthermore, as‐fabricated flexible Li‐air batteries containing the as‐prepared flexible super‐hydrophobic cathode show excellent mechanical properties, stable electrochemical performance, and superior H2O resistibility, which enhance their potential to power flexible and wearable electronic devices.  相似文献   

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