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81.
82.
Tropical forest responses are an important feedback on global change, but changes in forest composition with projected increases in CO2 and drought are highly uncertain. Here we determine shifts in the most competitive plant hydraulic strategy (the evolutionary stable strategy or ESS) from changes in CO2 and drought frequency and intensity. Hydraulic strategies were defined along a spectrum from drought avoidance to tolerance by physiology traits. Drought impacted competition more than CO2, with elevated CO2 reducing but not reversing drought‐induced shifts in the ESS towards more tolerant strategies. Trait plasticity and/or adaptation intensified these shifts by increasing the competitive ability of the drought tolerant relative to the avoidant strategies. These findings predict losses of drought avoidant evergreens from tropical forests under global change, and point to the importance of changes in precipitation during the dry season and constraints on plasticity and adaptation in xylem traits to forest responses. 相似文献
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84.
Matteo Gentili Xavier Lahaye Francesca Nadalin Guilherme P.F. Nader Emilia Puig Lombardi Solène Herve Nilushi S. De Silva Derek C. Rookhuizen Elina Zueva Christel Goudot Mathieu Maurin Aurore Bochnakian Sebastian Amigorena Matthieu Piel Daniele Fachinetti Arturo Londoño-Vallejo Nicolas Manel 《Cell reports》2019,26(13):3798
85.
The distribution of residues in a polypeptide sequence is a determinant of aggregation optimized by evolution
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Monsellier E Ramazzotti M de Laureto PP Tartaglia GG Taddei N Fontana A Vendruscolo M Chiti F 《Biophysical journal》2007,93(12):4382-4391
It has been shown that the propensity of a protein to form amyloid-like fibrils can be predicted with high accuracy from the knowledge of its amino acid sequence. It has also been suggested, however, that some regions of the sequences are more important than others in determining the aggregation process. Here, we have addressed this issue by constructing a set of “sequence scrambled” variants of the first 29 residues of horse heart apomyoglobin (apoMb1-29), in which the sequence was modified while maintaining the same amino acid composition. The clustering of the most amyloidogenic residues in one region of the sequence was found to cause a marked increase of the elongation rate (kagg) and a remarkable shortening of the lag phase (tlag) of the fibril growth, as determined by far-UV circular dichroism and thioflavin T fluorescence. We also show that taking explicitly into consideration the presence of aggregation-promoting regions in the predictive methods results in a quantitative agreement between the theoretical and observed kagg and tlag values of the apoMb1-29 variants. These results, together with a comparison between homologous segments from the family of globins, indicate the existence of a negative selection against the clustering of highly amyloidogenic residues in one or few regions of polypeptide sequences. 相似文献
86.
Contrasting behavior of higher plant photosystem I and II antenna systems during acclimation 总被引:1,自引:0,他引:1
Ballottari M Dall'Osto L Morosinotto T Bassi R 《The Journal of biological chemistry》2007,282(12):8947-8958
In this work we analyzed the photosynthetic apparatus in Arabidopsis thaliana plants acclimated to different light intensity and temperature conditions. Plants showed the ability to acclimate into different environments and avoid photoinhibition. When grown in high light, plants had a faster activation rate for energy dissipation (qE). This ability was correlated to higher accumulation levels of a specific photosystem II subunit, PsbS. The photosystem II antenna size was also regulated according to light exposure; smaller antenna size was observed in high light-acclimated plants with respect to low light plants. Different antenna polypeptides did not behave similarly, and Lhcb1, Lchb2, and Lhcb6 (CP24) are shown to undergo major levels of regulation, whereas Lhcb4 and Lhcb5 (CP29 and CP26) maintained their stoichiometry with respect to the reaction center in all growth conditions. The effect of acclimation on photosystem I antenna was different; in fact, the stoichiometry of any Lhca antenna proteins with respect to photosystem I core complex was not affected by growth conditions. Despite this stability in antenna stoichiometry, photosystem I light harvesting function was shown to be regulated through different mechanisms like the control of photosystem I to photosystem II ratio and the association or dissociation of Lhcb polypeptides to photosystem I. 相似文献
87.
Morán-Barrio J González JM Lisa MN Costello AL Peraro MD Carloni P Bennett B Tierney DL Limansky AS Viale AM Vila AJ 《The Journal of biological chemistry》2007,282(25):18286-18293
Metallo-beta-lactamases (MbetaLs) are zinc-dependent enzymes able to hydrolyze and inactivate most beta-lactam antibiotics. The large diversity of active site structures and metal content among MbetaLs from different sources has limited the design of a pan-MbetaL inhibitor. Here we report the biochemical and biophysical characterization of a novel MbetaL, GOB-18, from a clinical isolate of a Gram-negative opportunistic pathogen, Elizabethkingia meningoseptica. Different spectroscopic techniques, three-dimensional modeling, and mutagenesis experiments, reveal that the Zn(II) ion is bound to Asp120, His121, His263, and a solvent molecule, i.e. in the canonical Zn2 site of dinuclear MbetaLs. Contrasting all other related MbetaLs, GOB-18 is fully active against a broad range of beta-lactam substrates using a single Zn(II) ion in this site. These data further enlarge the structural diversity of MbetaLs. 相似文献
88.
Veiga E Guttman JA Bonazzi M Boucrot E Toledo-Arana A Lin AE Enninga J Pizarro-Cerdá J Finlay BB Kirchhausen T Cossart P 《Cell host & microbe》2007,2(5):340-351
Infection by the bacterium Listeria monocytogenes depends on host cell clathrin. To determine whether this requirement is widespread, we analyzed infection models using diverse bacteria. We demonstrated that bacteria that enter cells following binding to cellular receptors (termed "zippering" bacteria) invade in a clathrin-dependent manner. In contrast, bacteria that inject effector proteins into host cells in order to gain entry (termed "triggering" bacteria) invade in a clathrin-independent manner. Strikingly, enteropathogenic Escherichia coli (EPEC) required clathrin to form actin-rich pedestals in host cells beneath adhering bacteria, even though this pathogen remains extracellular. Furthermore, clathrin accumulation preceded the actin rearrangements necessary for Listeria entry. These data provide evidence for a clathrin-based entry pathway allowing internalization of large objects (bacteria and ligand-coated beads) and used by "zippering" bacteria as part of a general mechanism to invade host mammalian cells. We also revealed a nonendocytic role for clathrin required for extracellular EPEC infections. 相似文献
89.
Matteo Benussi 《The journal of the Royal Anthropological Institute》2022,28(1):30-51
This article advances a framework aimed at capturing the political life of ethical intensity by putting autonomist theory in resonance with ethnographic material pertaining to quietist Muslim milieus in post-Soviet Russia. The emancipatory and prefigurative potential of collective projects of self-legislation – in this case, ‘halal living’ – are explored through the notions of ethical form of life and Rule/Law. It will be argued that autonomist theory (a) is helpful in conceptualizing the friction between ethical projects (however quietist) and dominant moral/political orders; (b) has the potential to broaden anthropological conversations on virtue beyond existing fault lines (notably between what I call ‘traditionist’ and ‘liberal’ theoretical families) as well as conceptual silos (‘religion', ‘secularity’); and (c) can help us envision a radical, politically engaged anthropology of ethics. 相似文献
90.
Chiara Salvesi Stefania Silvi Dennis Fiorini Serena Scortichini Gianni Sagratini Francesco A. Palermo Renato De Leone Nadaniela Egidi Lorella Fatone Carlo Cifani Amedeo Amedei Francesca Scocchera Mara Morici Beatrice Gatto Fausto Mannucci Valerio Valeriani Marco Malavasi Sara Servili Andrea Casula Andrea Cresci Ivano Corradetti Francesco Carpi Matteo Picciolini Maria Magdalena Coman Maria Cristina Verdenelli 《Journal of applied microbiology》2022,133(5):2941-2953