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排序方式: 共有6625条查询结果,搜索用时 15 毫秒
941.
Gabriele Murineddu Francesco Deligia Giulio Ragusa Laura García-Toscano María Gómez-Cañas Battistina Asproni Valentina Satta Elena Cichero Ruth Pazos Paola Fossa Giovanni Loriga Javier Fernández-Ruiz Gerard A. Pinna 《Bioorganic & medicinal chemistry》2018,26(1):295-307
A series of sulfenamide and sulfonamide derivatives was synthesized and evaluated for the affinity at CB1 and CB2 receptors. The N-bornyl-S-(5,6-di-p-tolylpyridazin-3-yl)-sulfenamide, compound 11, displayed good affinity and high selectivity for CB1 receptors (Ki values of 44.6?nM for CB1 receptors and >40?μM for CB2 receptors, respectively). The N-isopinocampheyl-sulfenamide 12 and its sulfonamide analogue 22 showed similar selectivity for CB1 receptors with Ki values of 75.5 and 73.2?nM, respectively. These novel compounds behave as antagonists/inverse agonists at CB1 receptor in the [35S]-GTPγS binding assays, and none showed adequate predictive blood–brain barrier permeation, exhibiting low estimated LD50. However, testing compound 12 in a supraspinal analgesic test (hot-plate) revealed that it was as effective as the classic CB1 receptor antagonist rimonabant, in reversing the analgesic effect of a cannabinoid agonist. 相似文献
942.
943.
James O. Farlow Nathan J. Robinson Cory J. Kumagai Frank V. Paladino Peter L. Falkingham Ruth M. Elsey 《Ichnos》2018,25(1):30-65
We documented trackways of free-living Crocodylus acutus on beaches at the mouths of Tamarindo and Ventanas estuaries, Costa Rica. Our crocodiles had estimated total lengths of 1–3 meters or more. Manus prints have five digits, with digits I–III bearing claw marks. Pes prints have four digits, with claw marks on digits I–III. The pes is plantigrade. Claws generally dig into the substrate. Apart from claw marks, digit I and the heel of the pes are usually the most deeply impressed parts of footprints. Trackways are wide-gauge. Pes prints are usually positioned just behind ipsilateral manus prints of the same set and may overlap them. Manus and pes prints angle slightly outward with respect to the crocodile's direction of movement. Claw-bearing digits of both the manus and pes may create curved, concave-toward-the-midline drag marks as the autopodium is protracted. The tail mark varies in depth and clarity, and in shape from nearly linear to markedly sinuous. Sometimes the tail mark hugs the trackway midline, but sometimes it is closer to, or even cuts across, prints of one side. American crocodile footprints and trackways are similar to those observed in other extant crocodylian species, indicating substantial trackway conservatism across the group. 相似文献
944.
Seed limitation,not soil legacy effects,prevents native understorey from establishing in oak woodlands in Scotland after removal of Rhododendron ponticum
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Janet E. Maclean Ruth J. Mitchell David F. R. P. Burslem David Genney Jeanette Hall Robin J. Pakeman 《Restoration Ecology》2018,26(5):865-872
Following removal of the invasive species Rhododendron ponticum, the native understorey plant community typically fails to reestablish itself. Potential explanations for this failure include (1) lack of an appropriate native seed source; (2) inability of seed to penetrate a dense bryophyte layer; and (3) persistence of chemical “legacy effects” in the soil. We established an experiment to test these competing hypotheses in an Atlantic oak woodland where R. ponticum had been removed. The following experimental treatments were applied singly and in combination: (1) addition of a native seed mix to test for seed limitation; (2) removal of the established ground vegetation at the start of the experiment (which principally consisted of bryophytes) to test for the impact of a barrier layer; (3) addition of activated carbon to test for chemical legacy effects in the soil; and (4) fertilization as an additional measure to promote the establishment of native vascular plants. Application of the native seed mix was revealed to be an effective way to increase the cover of native vascular plants and was particularly effective when applied after the removal of the bryophyte layer. The application of activated carbon and/or fertilizer, however, had no effect on the cover of native vegetation. We conclude that reports of R. ponticum exerting chemical legacy effects long after its removal may have been overstated and that seed limitation and inability to successfully establish in a dense bryophyte layer provided the strongest barriers to natural recolonization by the native plant community following R. ponticum removal. 相似文献
945.
Physiological and proteomic analyses of Fe(III)‐reducing co‐cultures of Desulfotomaculum reducens MI‐1 and Geobacter sulfurreducens PCA
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Anne E. Otwell Stephen J. Callister Robert W. Sherwood Sheng Zhang Abby R. Goldman Richard D. Smith Ruth E. Richardson 《Geobiology》2018,16(5):522-539
We established Fe(III)‐reducing co‐cultures of two species of metal‐reducing bacteria, the Gram‐positive Desulfotomaculum reducens MI‐1 and the Gram‐negative Geobacter sulfurreducens PCA. Co‐cultures were given pyruvate, a substrate that D. reducens can ferment and use as electron donor for Fe(III) reduction. G. sulfurreducens relied upon products of pyruvate oxidation by D. reducens (acetate, hydrogen) for use as electron donor in the co‐culture. Co‐cultures reduced Fe(III) to Fe(II) robustly, and Fe(II) was consistently detected earlier in co‐cultures than pure cultures. Notably, faster cell growth, and correspondingly faster pyruvate oxidation, was observed by D. reducens in co‐cultures. Global comparative proteomic analysis was performed to observe differential protein abundance during co‐culture vs. pure culture growth. Proteins previously associated with Fe(III) reduction in G. sulfurreducens, namely c‐type cytochromes and type IV pili proteins, were significantly increased in abundance in co‐cultures relative to pure cultures. D. reducens ribosomal proteins were significantly increased in co‐cultures, likely a reflection of faster growth rates observed for D. reducens cells while in co‐culture. Furthermore, we developed multiple reaction monitoring (MRM) assays to quantitate specific biomarker peptides. The assays were validated in pure and co‐cultures, and protein abundance ratios from targeted MRM and global proteomic analysis correlate significantly. 相似文献
946.
Aude Nicolas Kevin P. Kenna Alan E. Renton Nicola Ticozzi Faraz Faghri Ruth Chia Janice A. Dominov Brendan J. Kenna Mike A. Nalls Pamela Keagle Alberto M. Rivera Wouter van Rheenen Natalie A. Murphy Joke J.F.A. van Vugt Joshua T. Geiger Rick A. Van der Spek Hannah A. Pliner John E. Landers 《Neuron》2018,97(6):1268-1283.e6
947.
Meryl Wang David Zhu Jianwei Zhu Ruth Nussinov Buyong Ma 《Journal of molecular recognition : JMR》2018,31(5)
Deciphering antibody‐protein antigen recognition is of fundamental and practical significance. We constructed an antibody structural dataset, partitioned it into human and murine subgroups, and compared it with nonantibody protein‐protein complexes. We investigated the physicochemical properties of regions on and away from the antibody‐antigen interfaces, including net charge, overall antibody charge distributions, and their potential role in antigen interaction. We observed that amino acid preference in antibody‐protein antigen recognition is entropy driven, with residues having low side‐chain entropy appearing to compensate for the high backbone entropy in interaction with protein antigens. Antibodies prefer charged and polar antigen residues and bridging water molecules. They also prefer positive net charge, presumably to promote interaction with negatively charged protein antigens, which are common in proteomes. Antibody‐antigen interfaces have large percentages of Tyr, Ser, and Asp, but little Lys. Electrostatic and hydrophobic interactions in the Ag binding sites might be coupled with Fab domains through organized charge and residue distributions away from the binding interfaces. Here we describe some features of antibody‐antigen interfaces and of Fab domains as compared with nonantibody protein‐protein interactions. The distributions of interface residues in human and murine antibodies do not differ significantly. Overall, our results provide not only a local but also a global anatomy of antibody structures. 相似文献
948.
949.
Daniel Padfield Angus Buckling Ruth Warfield Chris Lowe Gabriel Yvon‐Durocher 《Ecology letters》2018,21(8):1152-1161
Quantifying variation in ecosystem metabolism is critical to predicting the impacts of environmental change on the carbon cycle. We used a metabolic scaling framework to investigate how body size and temperature influence phytoplankton community metabolism. We tested this framework using phytoplankton sampled from an outdoor mesocosm experiment, where communities had been either experimentally warmed (+ 4 °C) for 10 years or left at ambient temperature. Warmed and ambient phytoplankton communities differed substantially in their taxonomic composition and size structure. Despite this, the response of primary production and community respiration to long‐ and short‐term warming could be estimated using a model that accounted for the size‐ and temperature dependence of individual metabolism, and the community abundance‐body size distribution. This work demonstrates that the key metabolic fluxes that determine the carbon balance of planktonic ecosystems can be approximated using metabolic scaling theory, with knowledge of the individual size distribution and environmental temperature. 相似文献
950.
Ankit X. Sharma Ezekiel B. Quittner-Strom Young Lee Joshua A. Johnson Sarah A. Martin Xinxin Yu Jianping Li John Lu Zheqing Cai Shiuhwei Chen May-yun Wang Yiyi Zhang Mackenzie J. Pearson Andie C. Dorn Jeffrey G. McDonald Ruth Gordillo Hai Yan Dung Thai William L. Holland 《Cell reports》2018,22(7):1760-1773