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41.
Beatrice Manser Teresa Koller Coraline Rosalie Praz Anne C. Roulin Helen Zbinden Sanu Arora Burkhard Steuernagel Brande B.H. Wulff Beat Keller Javier Sánchez-Martín 《The Plant journal : for cell and molecular biology》2021,106(4):993-1007
Plant nucleotide-binding leucine-rich repeat receptors (NLRs) act as intracellular sensors for pathogen-derived effector proteins and trigger an immune response, frequently resulting in the hypersensitive cell death response (HR) of the infected host cell. The wheat (Triticum aestivum) NLR Pm2 confers resistance against the fungal pathogen Blumeria graminis f. sp. tritici (Bgt) if the isolate contains the specific RNase-like effector AvrPm2. We identified and isolated seven new Pm2 alleles (Pm2e–i) in the wheat D-genome ancestor Aegilops tauschii and two new natural AvrPm2 haplotypes from Bgt. Upon transient co-expression in Nicotiana benthamiana, we observed a variant-specific HR of the Pm2 variants Pm2a and Pm2i towards AvrPm2 or its homolog from the AvrPm2 effector family, BgtE-5843, respectively. Through the introduction of naturally occurring non-synonymous single nucleotide polymorphisms and structure-guided mutations, we identified single amino acids in both the wheat NLR Pm2 and the fungal effector proteins AvrPm2 and BgtE-5843 responsible for the variant-specific HR of the Pm2 variants. Exchanging these amino acids led to a modified HR of the Pm2–AvrPm2 interaction and allowed the identification of the effector head epitope, a 20-amino-acid long unit of AvrPm2 involved in the HR. Swapping of the AvrPm2 head epitope to the non-HR-triggering AvrPm2 family member BgtE-5846 led to gain of a HR by Pm2a. Our study presents a molecular approach to identify crucial effector surface structures involved in the HR and demonstrates that natural and induced diversity in an immune receptor and its corresponding effectors can provide the basis for understanding and modifying NLR–effector specificity. 相似文献
42.
Hui Li Shuyi Wang Fang-Hua Lee Ryan S. Roark Alex I. Murphy Jessica Smith Chengyan Zhao Juliette Rando Neha Chohan Yu Ding Eunlim Kim Emily Lindemuth Katharine J. Bar Ivona Pandrea Cristian Apetrei Brandon F. Keele Jeffrey D. Lifson Mark G. Lewis Thomas N. Denny Barton F. Haynes Beatrice H. Hahn George M. Shaw 《Journal of virology》2021,95(11)
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Beatrice Sbriscia-Fioretti Cristina Berchio David Freedberg Vittorio Gallese Maria Alessandra Umiltà 《PloS one》2013,8(10)
The aim of this study was to test the involvement of sensorimotor cortical circuits during the beholding of the static consequences of hand gestures devoid of any meaning.In order to verify this hypothesis we performed an EEG experiment presenting to participants images of abstract works of art with marked traces of brushstrokes. The EEG data were analyzed by using Event Related Potentials (ERPs). We aimed to demonstrate a direct involvement of sensorimotor cortical circuits during the beholding of these selected works of abstract art. The stimuli consisted of three different abstract black and white paintings by Franz Kline. Results verified our experimental hypothesis showing the activation of premotor and motor cortical areas during stimuli observation. In addition, abstract works of art observation elicited the activation of reward-related orbitofrontal areas, and cognitive categorization-related prefrontal areas. The cortical sensorimotor activation is a fundamental neurophysiological demonstration of the direct involvement of the cortical motor system in perception of static meaningless images belonging to abstract art. These results support the role of embodied simulation of artist’s gestures in the perception of works of art. 相似文献
45.
Regulation of intracellular Ca2+ release in corpus cavernosum smooth muscle: synergism between nitric oxide and cGMP 总被引:1,自引:0,他引:1
Williams BA Liu C Deyoung L Brock GB Sims SM 《American journal of physiology. Cell physiology》2005,288(3):C650-C658
Tonic contraction of corpus cavernosum smooth muscle cells (SMCs) maintains the flaccid state of the penis, and relaxation is initiated by nitric oxide (NO), leading to erection. Our aim was to investigate the effect of NO on the smooth muscle cellular response to adrenergic stimulation in corpus cavernosum. Fura-2 fluorescence was used to record intracellular Ca2+ concentration ([Ca2+]i) from freshly isolated SMCs from rat and human. Phenylephrine (PE) transiently elevated [Ca2+]i in the presence and absence of extracellular Ca2+, indicating release from intracellular stores. Whereas the NO donor S-nitroso-N-acetylpenicillamine (SNAP) with sildenafil citrate (SIL) caused no change in basal [Ca2+]i, the PE-induced rise of [Ca2+]i was reversibly inhibited by 27 ± 7% (n = 21, P < 0.005) in rat and by 55 ± 15% (n = 9, P < 0.01) in human SMCs. SNAP and SIL also reduced the contractile response to PE. To investigate the mechanism, we applied mediators alone or in combination. The soluble guanylyl cyclase inhibitor ODQ reduced the effect of SNAP and SIL. SIL, cGMP analogs, and NO donors without SIL did not reduce the PE-induced rise of [Ca2+]i. However, the combination of 8-bromo-cGMP with SNAP reduced the Ca2+ peak by 42 ± 9% (n = 22, P < 0.01). Our results demonstrate that NO and cGMP act synergistically to reduce Ca2+ release from intracellular stores. Reduction of intracellular Ca2+ release may contribute to relaxation of the corpus cavernosum, leading to erection. calcium stores; nitric oxide; sildenafil citrate; inositol 1,4,5-trisphosphate receptor 相似文献
46.
Continental‐scale macrofungal assemblage patterns correlate with climate,soil carbon and nitrogen deposition 下载免费PDF全文
47.
Capecchi B Adu-Bobie J Di Marcello F Ciucchi L Masignani V Taddei A Rappuoli R Pizza M Aricò B 《Molecular microbiology》2005,55(3):687-698
Neisseria meningitidis is a human pathogen, which is a major cause of sepsis and meningitis. The bacterium colonizes the upper respiratory tract of approximately 10% of humans where it lives as a commensal. On rare occasions, it crosses the epithelium and reaches the bloodstream causing sepsis. From the bloodstream it translocates the blood-brain barrier, causing meningitis. Although all strains have the potential to cause disease, a subset of them, which belongs to hypervirulent lineages, causes disease more frequently than others. Recently, we described NadA, a novel antigen of N. meningitidis, present in three of the four known hypervirulent lineages. Here we show that NadA is a novel bacterial invasin which, when expressed on the surface of Escherichia coli, promotes adhesion to and invasion into Chang epithelial cells. Deletion of the N-terminal globular domain of recombinant NadA or pronase treatment of human cells abrogated the adhesive phenotype. A hypervirulent strain of N. meningitidis where the nad A gene was inactivated had a reduced ability to adhere to and invade into epithelial cells in vitro. NadA is likely to improve the fitness of N. meningitidis contributing to the increased virulence of strains that belong to the hypervirulent lineages. 相似文献
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J. Woodland Hastings Lazarus Astrachan Beatrice M. Sweeney 《The Journal of general physiology》1961,45(1):69-76
The luminescent marine dinoflagellate, Gonyaulax polyedra, exhibits a diurnal rhythm in the rate of photosynthesis and photosynthetic capacity measured by incorporation of C14O2, at different times of day. With cultures grown on alternating light and dark periods of 12 hours each, the maximum rate is at the 8th hour of the light period. Cultures transferred from day-night conditions to continuous dim light continue to show the rhythm of photosynthetic capacity (activity measured in bright light) but not of photosynthesis (activity measured in existing dim light). Cultures transferred to continuous bright light, however, do not show any rhythm. Several other properties of the photosynthetic rhythm are similar to those of previously reported rhythms of luminescence and cell division. This similarity suggests that a single mechanism regulates the various rhythms. 相似文献
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