Isolation and mapping of a C3'H gene (CYP98A49) from globe artichoke, and its expression upon UV-C stress

Globe artichoke represents a natural source of phenolic compounds with dicaffeoylquinic acids along with their biosynthetic precursor chlorogenic acid (5-caffeoylquinic acid) as the predominant molecules. We report the isolation and characterization of a full-length cDNA and promoter of a globe artichoke p-coumaroyl ester 3¿-hydroxylase (CYP98A49), which is involved in both chlorogenic acid and lignin biosynthesis. Phylogenetic analyses demonstrated that this gene belongs to the CYP98 family. CYP98A49 was also heterologously expressed in yeast, in order to perform an enzymatic assay with p-coumaroylshikimate and p-coumaroylquinate as substrates. Real Time quantitative PCR analysis revealed that CYP98A49 expression is induced upon exposure to UV-C radiation. A single nucleotide polymorphism in the CYP98A49 gene sequence of two globe artichoke varieties used for genetic mapping allowed the localization of this gene to linkage group 10 within the previously developed map

Magnetic order in double-layer manganites (La(1-z)Pr(z))1.2Sr1.8Mn2O7: intrinsic properties and role of the intergrowths

We report on an investigation of the double-layer manganite series (La(1-z)Pr(z))1.2Sr1.8Mn2O7 (0 <= z <= 1), carried out on single crystals by means of both macroscopic magnetometry and local probes of magnetism (muSR, 55Mn NMR). Muons and NMR demonstrate an antiferromagnetically ordered ground state at non-ferromagnetic compositions (z >= 0.6), while more moderate Pr substitutions (0.2 <= z <= 0.4) induce a spin reorientation transition within the ferromagnetic phase. A large magnetic susceptibility is detected at {Tc,TN} < T < 250K at all compositions. From 55Mn NMR spectroscopy, such a response is unambiguously assigned to the intergrowth of a ferromagnetic pseudocubic phase (La(1-z)Pr(z))(1-x)Sr(x)MnO3, with an overall volume fraction estimated as 0.5-0.7% from magnetometry. Evidence is provided for the coupling of the magnetic moments of these inclusions with the magnetic moments of the surrounding (La(1-z)Pr(z))1.2Sr1.8Mn2O7 phase, as in the case of finely dispersed impurities. We argue that the ubiquitous intergrowth phase may play a role in the marked first-order character of the magnetic transition and the metamagnetic properties above Tc reported for double-layer manganites.Comment: 11 pages, 9 figures. Submitted to Phys. Rev.

On an exact solution of the Thomas-Fermi equation for a trapped Bose-Einstein condensate with dipole-dipole interactions

We derive an exact solution to the Thomas-Fermi equation for a Bose-Einstein condensate which has dipole-dipole interactions as well as the usual s-wave contact interaction, in a harmonic trap. Remarkably, despite the non-local anisotropic nature of the dipolar interaction the solution is an inverted parabola, as in the pure s-wave case, but with a different aspect ratio. Various properties such as electrostriction and stability are discussed.Comment: 11 pages, 5 figure

Observation of Individual Josephson Vortices in YBCO Bicrystal Grain-boundary Junctions

The response of YBCO bicrystal grain-boundary junctions to small dc magnetic fields (0 - 10 Oe) has been probed with a low-power microwave (rf) signal of 4.4 GHz in a microwave-resonator setup. Peaks in the microwave loss at certain dc magnetic fields are observed that result from individual Josephson vortices penetrating into the grain-boundary junctions under study. The system is modeled as a long Josephson junction described by the sine-Gordon equation with the appropriate boundary conditions. Excellent quantitative agreement between the experimental data and the model has been obtained. Hysteresis effect of dc magnetic field is also studied and the results of measurement and calculation are compared.Comment: 11 pages, 4 figure

Non-resonant microwave absorption studies of superconducting MgB_2

Non-resonant microwave absorption(NRMA) studies of superconducting MgB_2 at a frequency of 9.43 GHz in the field range -50 Gauss to 5000 Gauss are reported. The NRMA results indicate near absence of intergranular weak links. A linear temperature dependence of the lower critical field H_c1 is observed indicating a non s-wave superconductivity. However, the phase reversal of the NRMA signal which could suggest d-wave symmetry is also not observed.Comment: 8 pages, 2 figure

Faraday effect : a field theoretical point of view

We analyze the structure of the vacuum polarization tensor in the presence of a background electromagnetic field in a medium. We use various discrete symmetries and crossing symmetry to constrain the form factors obtained for the most general case. From these symmetry arguments, we show why the vacuum polarization tensor has to be even in the background field when there is no background medium. Taking then the background field to be purely magnetic, we evaluate the vacuum polarization to linear order in it. The result shows the phenomenon of Faraday rotation, i.e., the rotation of the plane of polarization of a plane polarized light passing through this background. We find that the usual expression for Faraday rotation, which is derived for a non-degenerate plasma in the non-relativistic approximation, undergoes substantial modification if the background is degenerate and/or relativistic. We give explicit expressions for Faraday rotation in completely degenerate and ultra-relativistic media.Comment: 20 pages, Latex, uses axodraw.st

Location of chlorogenic acid biosynthesis pathway and polyphenol oxidase genes in a new interspecific anchored linkage map of eggplant

© Gramazio et al.; licensee BioMed Central. 2014. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

Critical State Flux Penetration and Linear Microwave Vortex Response in YBa_2Cu_3O_{7-x} Films

The vortex contribution to the dc field (H) dependent microwave surface impedance Z_s = R_s+iX_s of YBa_2Cu_3O_{7-x} thin films was measured using suspended patterned resonators. Z_s(H) is shown to be a direct measure of the flux density B(H) enabling a very precise test of models of flux penetration. Three regimes of field-dependent behavior were observed: (1) Initial flux penetration occurs on very low field scales H_i(4.2K) 100Oe, (2) At moderate fields the flux penetration into the virgin state is in excellent agreement with calculations based upon the field-induced Bean critical state for thin film geometry, parametrized by a field scale H_s(4.2K) J_c*d 0.5T, (3) for very high fields H >>H_s, the flux density is uniform and the measurements enable direct determination of vortex parameters such as pinning force constants \alpha_p and vortex viscosity \eta. However hysteresis loops are in disagreement with the thin film Bean model, and instead are governed by the low field scale H_i, rather than by H_s. Geometric barriers are insufficient to account for the observed results.Comment: 20 pages, LaTeX type, Uses REVTeX style files, Submitted to Physical Review B, 600 dpi PostScript file with high resolution figures available at http://sagar.physics.neu.edu/preprints.htm

Non-linear microwave impedance of short and long Josephson Junctions

The non-linear dependence on applied $ac$ field ($b_{\omega}$) or current ($i_{\omega}$) of the microwave (ac) impedance $R_{\omega}+iX_{\omega}$ of both short and long Josephson junctions is calculated under a variety of excitation conditions. The dependence on the junction width is studied, for both field symmetric (current anti-symmetric) and field anti-symmetric (current symmetric) excitation configurations.The resistance shows step-like features every time a fluxon (soliton) enters the junction, with a corresponding phase slip seen in the reactance. For finite widths the interference of fluxons leads to some interesting effects which are described. Many of these calculated results are observed in microwave impedance measurements on intrinsic and fabricated Josephson junctions in the high temperature superconductors, and new effects are suggested. When a $$ field ($b_{dc}$) or current ($i_{dc}$) is applied, interesting phase locking effects are observed in the ac impedance $Z_{\omega}$. In particular an almost periodic dependence on the dc bias is seen similar to that observed in microwave experiments at very low dc field bias. These results are generic to all systems with a $\cos (\phi)$ potential in the overdamped limit and subjected to an ac drive.Comment: 7 pages, 11 figure

Nuclear spin-spin coupling in La_{2-x}Sr_{x}CuO_{4} studied by stimulated echo decay

We have performed copper NQR experiments in high temperature superconductors YBa_{2}Cu_{4}O_{8}, YBa_{2}Cu_{3}O_{7}, and La_{2-x}Sr_{x}CuO_{4} (x=0.12 and 0.15), using the stimulated echo technique. The stimulated echo intensity is analyzed by a model that includes the spin-lattice relaxation process (T_ {1 }-process) and the fluctuating local field due to nuclear spin-spin coupling. The model gives quantitative account of the experimental results in Y-based compounds using the known values of 1/T_{1} and 1/T_{2G}, the gaussian decay rate of the spin echo intensity. The same model applied to LSCO enables us to extract the value of T_{2G}. Our results indicate that T_{1}T/T_{2G} is independent of temperature, implying that the dynamic exponent is one in La_{2-x}Sr_{x}CuO_{4}.Comment: 14 pages, 11 fugures, The bibliography field is correcte