31,294 research outputs found
Functional analysis and binding affinity of tomato ethylene response factors provide insight on the molecular bases of plant differential responses to ethylene
No full textBackground : The phytohormone ethylene is involved in a wide range of developmental processes and in mediating plant responses to biotic and abiotic stresses. Ethylene signalling acts via a linear transduction pathway leading to the activation of Ethylene Response Factor genes (ERF)which represent one of the largest gene families of plant transcription factors. How an apparently simple signalling pathway can account for the complex and widely diverse plant responses to ethylene remains yet an unanswered question. Building on the recent release of the complete tomato genome sequence, the present study aims at gaining better insight on distinctive features among ERF proteins. Results : A set of 28 cDNA clones encoding ERFs in the tomato (Solanum lycopersicon) were isolated and shown to fall into nine distinct subclasses characterised by specific conserved motifs most of which with unknown function. In addition of being able to regulate the transcriptional activity of GCC-box containing promoters, tomato ERFs are also shown to be active on promoters lacking this canonical ethylene-responsive-element. Moreover, the data reveal that ERF affinity to the GCC-box depends on the nucleotide environment surrounding this cis-acting element. Site-directed mutagenesis revealed that the nature of the flanking nucleotides can either enhance or reduce the binding affinity, thus conferring the binding specificity of various ERFs to target promoters. Based on their expression pattern, ERF genes can be clustered in two main clades given their preferential expression in reproductive or vegetative tissues. The regulation of several tomato ERF genes by both ethylene and auxin, suggests their potential contribution to the convergence mechanism between the signalling pathways of the two hormones. Conclusions : The data reveal that regions flanking the core GCC-box sequence are part of the discrimination mechanism by which ERFs selectively bind to their target promoters. ERF tissue-specific expression combined to their responsiveness to both ethylene and auxin bring some insight on the complexity and fine regulation mechanisms involving these transcriptional mediators. All together the data support the hypothesis that ERFs are the main component enabling ethylene to regulate a wide range of physiological processes in a highly specific and coordinated manner
The Effect of Mannan Oligosaccharides on Growth and Immune Responses of Weanling Pigs
No full textDavis, M. E.; Maxwell, C. V.; Brown, D. C.; Erf, G. F.; Wistuba, T. J.. (2002). The Effect of Mannan Oligosaccharides on Growth and Immune Responses of Weanling Pigs. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/160359
[Goethe's Faust] / Engelbert Seibertz erf. u. gez. Adrian Schleich gest.
No full text[GOETHE'S FAUST] / ENGELBERT SEIBERTZ ERF. U. GEZ. ADRIAN SCHLEICH GEST.
[Goethe's Faust] / Engelbert Seibertz erf. u. gez. Adrian Schleich gest. (1)
Titelblatt (1)
Illustration Bl. m - j (2)
Illustration Bl. i - f (10)
Illustration Bl. e - a (18
Erratum to: Effect of moderate red wine intake on cardiac prognosis after recent acute myocardial infarction of subjects with Type 2 diabetes mellitus (Diabetic Medicine, (2006), 23, 9, (974-981), 10.1111/j.1464-5491.2006.01886.x)
No full textIn an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola.In an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola
Elaboration on Kwapien's theorem: Representing bounded mean zero functions f as coboundary f = g ◦ T − g
No full textIn [8] Kwapien proved that every mean zero function f ∈ L∞[0, 1] we can write as f = g ◦ T − g for some g ∈ L∞[0, 1] and some measure preserving transformation T of [0, 1]. However, as was discovered in [4] there is a gap in the proof for the case that f is not continuous. The aim of this bachelor thesis is filling in that gap in the proof. We first extend Kwapien’s proof for continuous functions to certain other measure spaces. Thereafter, we use the method of proof suggested by Kwapien, to proof the theorem for mean zero function f ∈ L∞[0, 1] for which λ(f−1({x})) = 0 for all x ∈ R. Using this result we then proof that every mean zero function f ∈ L∞[0, 1] can be written as a sum f =(g1 ◦ T1 − g1) + (g2 ◦ T2 − g2) where g1, g2 ∈ L∞[0, 1] and where T1, T2 are measure preserving transformations of [0, 1]. We finish this thesis with an application of Kwapien’s theorem in the study to singular traces Applied Mathematic
Nitric oxide sensing in plants is mediated by proteolytic control of group VII ERF transcription factors
No full textNitric oxide (NO) is an important signaling compound in prokaryotes and eukaryotes. In plants, NO regulates critical developmental transitions and stress responses. Here, we identify a mechanism for NO sensing that coordinates responses throughout development based on targeted degradation of plant-specific transcriptional regulators, the group VII ethylene response factors (ERFs). We show that the N-end rule pathway of targeted proteolysis targets these proteins for destruction in the presence of NO, and we establish them as critical regulators of diverse NO-regulated processes, including seed germination, stomatal closure, and hypocotyl elongation. Furthermore, we define the molecular mechanism for NO control of germination and crosstalk with abscisic acid (ABA) signaling through ERF-regulated expression of ABSCISIC ACID INSENSITIVE5 (ABI5). Our work demonstrates how NO sensing is integrated across multiple physiological processes by direct modulation of transcription factor stability and identifies group VII ERFs as central hubs for the perception of gaseous signals in plants
A dominant repressor version of the tomatoSl-ERF.B3gene confers ethylene hypersensitivity via feedback regulation of ethylene signaling and response components
No full textEthylene Response Factors (ERFs) are downstream components of the ethylene signal transduction pathway, although their role in ethylene-dependent developmental processes remains poorly understood. As the ethylene-inducible tomato Sl-ERF.B3 has been shown previously to display a strong binding affinity to GCC-box-containing promoters, its physiological significance was addressed here by a reverse genetics approach. However, classical up- and down-regulation strategies failed to give clear clues to its roles in planta, probably due to functional redundancy among ERF family members. Expression of a dominant repressor ERF.B3-SRDX version of Sl-ERF.B3 in the tomato resulted in pleiotropic ethylene responses and vegetative and reproductive growth phenotypes. The dominant repressor etiolated seedlings displayed partial constitutive ethylene response in the absence of ethylene and adult plants exhibited typical ethylene-related alterations such as leaf epinasty, premature flower senescence and accelerated fruit abscission. The multiple symptoms related to enhanced ethylene sensitivity correlated with the altered expression of ethylene biosynthesis and signaling genes and suggested the involvement of Sl-ERF.B3 in a feedback mechanism that regulates components of ethylene production and response. Moreover, Sl-ERF.B3 was shown to modulate the transcription of a set of ERFs and revealed the existence of a complex network interconnecting different ERF genes. Overall, the study indicated that Sl-ERF.B3 had a critical role in the regulation of multiple genes and identified a number of ERFs among its primary targets, consistent with the pleiotropic phenotypes displayed by the dominant repression lines
TWO-PHOTON SPECTROSCOPY OF THE AND STATES OF
No full text Research supported by AFOSR K. Hoshiba et al. J. Phys. B 18, 1.875 (1985). T. Sakai et al., J. Phys. B. 21, 229 (1988).Author Institution: Molecular Physics Laboratory, SRI InternationalThe and states of are excited from the ground by two photons near 207 nm and detected by vuv fluorescence or by ionization by a third photon. The laser source for these measurements is an excimer-pumped dye laser operating with PBBO dye at 415 nm. This light is doubled in a crystal and focused into a cell containing a mixture of in He. The uv wavelengths were calibrated against the (3.0) band in NO, which was calibrated against in the visible. Vibrational levels were observed in the state and in the state, based on the previous electron-impact , and partially resolved rotationally (the effective excitation linewidth is ). These assignments are supported by simulations of the two-photon excitation spectra. Although the fluorescence has not yet been spectrally resolved, we believe that it arises predominantly from the triplet state even when the singlet is initially excited. In the latter case, the fluorescence is temporally delayed, and increases in intensity as the He density is increased. The two-phonon excitation scheme we have developed should be useful in investigating the kinetics of the 158 nm laser, which is believed to arise from a transition from the outer well of the state to a weakly bound state correlating to ground state atoms.$^{2}
Free product subgroups between Chevalley groups G(Φ,F) and G(Φ,F[t])
No full textAbstractWe investigate subgroups of a Chevalley group G=G(Φ,A) over a ring A, containing its elementary subgroup E=E(Φ,F) over a subring F⊆A. Assume that the root system Φ is simply laced and A=F[t] is a polynomial ring. We show that if G is of adjoint type, then there exists an element g∈E(Φ,A) such that 〈g,E(Φ,F)〉=〈g〉*E(Φ,F), where 〈X〉 denotes the subgroup, generated by a set X, and * stands for the free product.It follows that under the above assumptions the lattice L=L(E,G) is not standard. Moreover, combining the above result with theorems of Nuzhin and the author one obtains a necessary and sufficient condition for L to be standard provided that A and F are fields of characteristic not 2 and Φ≠G2
- …
