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991.
Osmotic stress decreases complexity underlying the electrophysiological dynamic in soybean 下载免费PDF全文
- Studies on plant electrophysiology are mostly focused on specific traits of single cells. Inspired by the complexity of the signalling network in plants, and by analogy with neurons in human brains, we sought evidence of high complexity in the electrical dynamics of plant signalling and a likely relationship with environmental cues.
- An EEG‐like standard protocol was adopted for high‐resolution measurements of the electrical signal in Glycine max seedlings. The signals were continuously recorded in the same plants before and after osmotic stimuli with a ?2 MPa mannitol solution. Non‐linear time series analyses methods were used as follows: auto‐correlation and cross‐correlation function, power spectra density function, and complexity of the time series estimated as Approximate Entropy (ApEn).
- Using Approximate Entropy analysis we found that the level of temporal complexity of the electrical signals was affected by the environmental conditions, decreasing when the plant was subjected to a low osmotic potential. Electrical spikes observed only after stimuli followed a power law distribution, which is indicative of scale invariance.
- Our results suggest that changes in complexity of the electrical signals could be associated with water stress conditions in plants. We hypothesised that the power law distribution of the spikes could be explained by a self‐organised critical state (SOC) after osmotic stress.
992.
Trade‐off relationship between productivity and thallus toughness in Laminariales (Phaeophyceae) 下载免费PDF全文
Trade‐off relationships are considered key to understanding the mechanisms supporting the coexistence of multiple species within kelp beds. Thus, information on trade‐offs is expected to contribute to conservation of kelp bed diversity. To test the existence of a trade‐off between productivity and thallus toughness, thallus traits and relationships between the traits were examined for seven species of Laminariales including 24 populations. For each population, photosynthetic capacity per unit biomass (as A mass) and nitrogen (i.e., photosynthetic nitrogen‐use efficiency, PNUE), nitrogen content (as N mass), thallus mass per unit thallus area (as TMA) and force required to penetrate the thallus (as F p, a common index of leaf toughness in land plants by punch test) were determined. A mass increased with increasing N mass. Blades with high N mass showed high A mass. These blades may invest a large proportion of nitrogen to the photosynthetic parts, and consequently exhibit high metabolic rates. Moreover, blades with high N mass tended to be associated with low TMA, and N mass decreased with increasing TMA. A significant negative correlation was observed between TMA and A mass because of the linkage of high A mass with high N mass and high N mass associated with low TMA, while a significant positive correlation was observed between TMA and F p. The two correlations indicate the existence of a trade‐off between productivity and thallus toughness in Laminariales. PNUE showed a significant negative correlation with TMA, which also showed a significant positive correlation with F p as the index of thallus toughness, and therefore a trade‐off relationship between productivity and thallus toughness. 相似文献
993.
Timo Heinrich Hans-Peter Buchstaller Bertram Cezanne Felix Rohdich Jörg Bomke Manja Friese-Hamim Mireille Krier Thorsten Knöchel Djordje Musil Birgitta Leuthner Frank Zenke 《Bioorganic & medicinal chemistry letters》2017,27(3):551-556
The natural product fumagillin 1 and derivatives like TNP-470 2 or beloranib 3 bind to methionine aminopeptidase 2 (MetAP-2) irreversibly. This enzyme is critical for protein maturation and plays a key role in angiogenesis. In this paper we describe the synthesis, MetAP-2 binding affinity and structural analysis of reversible MetAP-2 inhibitors. Optimization of enzymatic activity of screening hit 10 (IC50: 1 μM) led to the most potent compound 27 (IC50: 0.038 μM), with a concomitant improvement in LLE from 2.1 to 4.2. Structural analysis of these MetAP-2 inhibitors revealed an unprecedented conformation of the His339 side-chain imidazole ring being co-planar sandwiched between the imidazole of His331 and the aryl-ether moiety, which is bound to the purine scaffold. Systematic alteration and reduction of H-bonding capability of this metal binding moiety induced an unexpected 180° flip for the triazolo[1,5-a]pyrimdine bicyclic template. 相似文献
994.
Possibilities of the linear-polarized infrared (IR-LD) spectroscopy of oriented colloid suspensions in nematic liquid crystals, for structural and local structural elucidation for first time are demonstrated of inorganic compounds and glasses. The advantages of the method for tellurite and borate glasses are shown. The IR-band assignment of the typical local structural units in the glasses are proposed by a comparison with the IR-characteristics of appropriate crystalline analogues as α-TeO2, V2O5, MoO3 · H2O and its high temperature form. The IR-spectroscopic characteristics of BO3, BO4 and boroxol ring are elucidated, using crystalline β-BaB2O4, SrB4O7, H3BO3 and B2O3 as model systems, where the structural moieties have been refined by single crystal X-ray diffraction. 相似文献
995.
Charpentier TH Wilder PT Liriano MA Varney KM Pozharski E MacKerell AD Coop A Toth EA Weber DJ 《Journal of molecular biology》2008,382(1):56-73
As part of an effort to inhibit S100B, structures of pentamidine (Pnt) bound to Ca2+-loaded and Zn2+,Ca2+-loaded S100B were determined by X-ray crystallography at 2.15 Å (Rfree = 0.266) and 1.85 Å (Rfree = 0.243) resolution, respectively. These data were compared to X-ray structures solved in the absence of Pnt, including Ca2+-loaded S100B and Zn2+,Ca2+-loaded S100B determined here (1.88 Å; Rfree = 0.267). In the presence and absence of Zn2+, electron density corresponding to two Pnt molecules per S100B subunit was mapped for both drug-bound structures. One Pnt binding site (site 1) was adjacent to a p53 peptide binding site on S100B (± Zn2+), and the second Pnt molecule was mapped to the dimer interface (site 2; ± Zn2+) and in a pocket near residues that define the Zn2+ binding site on S100B. In addition, a conformational change in S100B was observed upon the addition of Zn2+ to Ca2+-S100B, which changed the conformation and orientation of Pnt bound to sites 1 and 2 of Pnt-Zn2+,Ca2+-S100B when compared to Pnt-Ca2+-S100B. That Pnt can adapt to this Zn2+-dependent conformational change was unexpected and provides a new mode for S100B inhibition by this drug. These data will be useful for developing novel inhibitors of both Ca2+- and Ca2+,Zn2+-bound S100B. 相似文献
996.
Makino N Toyofuku T Takegahara N Takamatsu H Okuno T Nakagawa Y Kang S Nojima S Hori M Kikutani H Kumanogoh A 《FEBS letters》2008,582(28):3935-3940
Dilated cardiomyopathy often results from autoimmunity triggered by microbial infections during myocarditis. However, it remains unclear how immunological disorders are implicated in pathogenesis of autoimmune myocarditis. Here, we demonstrated that Sema4A, a class IV semaphorin, plays key roles in experimental autoimmune myocarditis (EAM). Dendritic cells pulsed with myosin heavy chain-α peptides induced severe myocarditis in wild-type mice, but not in Sema4A-deficient mice. In adoptive transfer experiments, CD4+ T-cells from wild-type mice induced severe myocarditis, while CD4+ T-cells from Sema4A-deficient mice exhibited considerably attenuated myocarditis. Our results indicated that Sema4A is critically involved in EAM by regulating differentiation of T-cells. 相似文献
997.
P2X7 receptor inhibition attenuated sympathetic nerve sprouting after myocardial infarction via the NLRP3/IL‐1β pathway 下载免费PDF全文
Hesheng Hu Xiaolu Li Mei Xue Wenjuan Cheng Ye Wang Xinran Li Na Yang Yugen Shi Suhua Yan 《Journal of cellular and molecular medicine》2017,21(11):2695-2710
Mounting evidence supports the hypothesis that inflammation modulates sympathetic sprouting after myocardial infarction (MI). The myeloid P2X7 signal has been shown to activate the nucleotide‐binding and oligomerization domain‐like receptor family pyrin domain‐containing 3 (NLRP3) inflammasome, a master regulator of inflammation. We investigated whether P2X7 signal participated in the pathogenesis of sympathetic reinnervation after MI, and whether NLRP3/interleukin‐1β (IL‐1β) axis is involved in the process. We explored the relationship between P2X7 receptor (P2X7R) and IL‐1β in the heart tissue of lipopolysaccharide (LPS)‐primed naive rats. 3′‐O‐(4‐benzoyl) benzoyl adenosine 5′‐triphosphate (BzATP), a P2X7R agonist, induced caspase‐1 activation and mature IL‐1β release, which was further neutralized by a NLRP3 inhibitor (16673‐34‐0). MI was induced by coronary artery ligation. Following infarction, a marked increase in P2X7R was localized within infiltrated macrophages and observed in parallel with an up‐regulation of NLRP3 inflammasome levels and the release of IL‐1β in the left ventricle. The administration of A‐740003 (a P2X7R antagonist) significantly prevented the NLRP3/IL‐1β increase. A‐740003 and/or Anakinra (an IL‐1 receptor antagonist) significantly reduced macrophage infiltration as well as macrophage‐based IL‐1β and NGF (nerve growth factor) production and eventually blunted sympathetic hyperinnervation, as assessed by the immunofluorescence of tyrosine hydroxylase (TH) and growth‐associated protein 43 (GAP 43). Moreover, the use of Anakinra partly attenuated sympathetic sprouting. This indicated that the effect of P2X7 on neural remodelling was mediated at least partially by IL‐1β. The arrhythmia score of programmed electric stimulation was in accordance with the degree of sympathetic hyperinnervation. In vitro studies showed that BzATP up‐regulated secretion of nerve growth factor (NGF) in M1 macrophages via IL‐1β. Together, these data indicate that P2X7R contributes to neural and cardiac remodelling, at least partly mediated by NLRP3/IL‐1β axis. Therapeutic interventions targeting P2X7 signal may be a novel approach to ameliorate arrhythmia following MI. 相似文献
998.
Methylglyoxal‐induced apoptosis is dependent on the suppression of c‐FLIPL expression via down‐regulation of p65 in endothelial cells 下载免费PDF全文
999.
1000.