14,824 research outputs found
Silencing Sl-EBF1 and Sl-EBF2 expression causes constitutive ethylene response phenotype, accelerated plant senescence, and fruit ripening in tomato
Full text linkThe hormone ethylene regulates a wide range of plant developmental processes and EBF (EIN3-binding F-box) proteins were shown to negatively regulate the ethylene signalling pathway via mediating the degradation of EIN3/EIL proteins. The present study reports on the identification of two tomato F-box genes, Sl-EBF1 and Sl-EBF2 from the EBF subfamily. The two genes display contrasting expression patterns in reproductive and vegetative tissues and in response to ethylene and auxin treatment. Sl-EBF1 and Sl-EBF2 genes are actively regulated at crucial stages in the development of the reproductive organs. Their dynamic expression in flowers during bud-to-anthesis and anthesis-to-post-anthesis transitions, and at the onset of fruit ripening, suggests their role in situations where ethylene is required for stimulating flower opening and triggering fruit ripening. VIGS-mediated silencing of a single tomato EBF gene uncovered a compensation mechanism that tends to maintain a threshold level of Sl-EBF expression via enhancing the expression of the second Sl-EBF gene. In line with this compensation, tomato plants silenced for either of the Sl-EBF genes were indistinguishable from control plants, indicating functional redundancy among Sl-EBF genes. By contrast, co-silencing of both Sl-EBFs resulted in ethylene-associated phenotypes. While reports on EBF genes to date have focused on their role in modulating ethylene responses in Arabidopsis, the present study uncovered their role in regulating crucial stages of flower and fruit development in tomato. The data support the hypothesis that protein degradation via the ubiquitin/26S proteasome pathway is a control point of fruit ripening and open new leads for engineering fruit quality
Punctulata fusciptera Wang 2006
No full textPunctulata fusciptera Wang, 2006 (Figs 6, 14, 16) Punctulata fusciptera Wang, 2006: 158. TL: China (Hubei). TD: NKU. Material examined. Type material. CHINA, Hubei: Holotype ♂, Shennongjia (31.45 °N, 110.40°E), 1100 m, 19.VII.2003, leg. SL Hao, slide No. W03186. Paratypes: 2♂ 1♀, 17–18.VII.2003, other data as holotype, slide Nos. W04020 ♂, W04024 ♀. Diagnosis. Punctulata fusciptera (Fig. 6) is similar to P. ningshanensis (Fig. 7) in appearance and in male genitalia, but it can be distinguished from the latter by the less sclerotized distal portion of the uncus, the slender basal process of the costa pointed at apex, and the distally dilated valva (Fig. 14). In P. ningshanensis, the distal portion of the uncus is heavily sclerotized, the stout basal process of the costa is rounded at apex, and the valva is slightly widened distally (Fig. 12). The female genitalia are diagnostic by the funneled antrum and the ductus seminalis arising from the middle of the ductus bursae (Fig. 16). Distribution. China (Hubei).Published as part of Tao, Zhulin & Wang, Shuxia, 2021, Taxonomic study of the genus Punctulata Wang (Lepidoptera: Autostichidae) from China, with descriptions of two new species, pp. 376-386 in Zootaxa 5027 (3) on page 382, DOI: 10.11646/zootaxa.5027.3.4, http://zenodo.org/record/544970
Assessments of spasticity by Hoffmann reflex parameters in patients with spinal cord injury.
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Tensor hierarchy and generalized Cartan calculus in SL(3) × SL(2) exceptional field theory
Full text linkWe construct exceptional field theory for the duality group SL(3) × SL(2). The theory is defined on a space with 8 ‘external’ coordinates and 6 ‘internal’ coordinates in the (3, 2) fundamental representation, leading to a 14-dimensional generalized spacetime. The bosonic theory is uniquely determined by gauge invariance under generalized external and internal diffeomorphisms. The latter invariance can be made manifest by introducing higher form gauge fields and a so-called tensor hierarchy, which we systematically develop to much higher degree than in previous studies. To this end we introduce a novel Cartan-like tensor calculus based on a covariant nil-potent differential, generalizing the exterior derivative of conventional differential geometry. The theory encodes the full D = 11 or type IIB supergravity, respectively.United States. Dept. of Energy (Cooperative Research Agreement DE-FG02-05ER41360)German Science Foundation (Heisenberg Fellowship
Enhancing the dynamic temperature stability of epoxy with graphene oxide
No full textTemperature-dependence mechanism of composites under dynamic loadings is essential for designing the aircraft with harsh operation environment. In this work, the dynamic compression mechanical behavior of graphene oxide modified epoxy (GO-epoxy) was systematically investigated over the temperature range from 298K to 423K under the loading strain rate of 5000 s(-1). The results indicate that the compression properties of GO-epoxy are sensitive to the strain rate and temperature. The yield strength of pure epoxy and GO-epoxy under dynamic loading were twice those under quasi-static loading. The strength gradually decreases as the temperature increases, but the temperature stability of GO-epoxy is significantly improved compared to the pure epoxy. The addition of GO helps to inhibit the movement of the molecular chain, suppress the stress softening, prevent the evolution of the micro-cracks and then increase the thermal stability of epoxy. The high speed photograph combined with the digital image correction (DIC) method indicates that GO improves the impact resistance of epoxy at different temperatures and the interfacial interactions contribute to this strengthening mechanism. A modified temperature and rate-dependent empirical constitutive model was developed to describe the dynamic behavior of pure/GO epoxy. The fracture morphologies show the difference failure modes between the GO-epoxy and the pure epoxy. This work on the temperature dependent dynamic behavior of GO modified epoxy could provide guidance for understanding the dynamic strengthening and thermal softening behaviors of nano-reinforcing composites
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