PHYSIOLOGICAL CHARACTERIZATION OF A HIGH-PIGMENT MUTANT OF TOMATO

Abstract— A high-pigment (hp) mutant, which shows exaggerated phytochrome responses and three other genotypes of Lycopersicon esculenrum Mill. cv. Ailsa Craig: the aurea (au) mutant deficient in the bulk light-labile phytochrome (PI) pool, the au, hp double mutant, and their isogenic wild type, were used in this study. Measurements of phytochrome destruction in red light (R) revealed that the exaggerated responses of the hp mutant are not caused by a higher absolute phytochrome level or a reduced rate of phytochrome destruction. Fluence-response relationships for anthocyanin synthesis after a blue-light pretreatment were studied to test if the hp mutant conveys hypersensitivity to the far-red light (FR)-absorbing form of phytochrome (Pfr), i.e. the threshold of Pfr required to initiate the response is lower. The response range for the hp mutant and wild type was identical, although the former exhibited a 6-fold larger response. Moreover, the kinetics of anthocyanin accumulation in continuous R were similar in the wild-type and hp-mutant seedlings, despite the latter accumulating 9-fold more anthocyanin. Since the properties of phytochrome are the same, the hp mutation appears to affect the state of responsiveness amplification, i.e. the same amount of Pfr leads to a higher response in the hp mutant. We therefore propose that the hp mutation is associated with an amplification step in the phytochrome transduction chain. Escape experiments showed that the anthocyanin synthesis after different light pretreatments terminated with a R pulse was still 50% FR reversible after 4–6 h darkness, indicating that the Pfr pool regulating this response must be relatively stable. However, fluence-rate response relationships for anthocyanin synthesis and hypocotyl growth induced by a 24-h irradiation with 451, 539, 649, 693, 704 and 729 nm light showed no or a severely reduced response in the au and au, hp mutants, suggesting the importance of PI in these responses. We therefore propose that the capacity for anthocyanin synthesis (state of responsiveness amplification) could be established by PI, while the anthocyanin synthesis is actually photoregulated via a stable Pfr pool. The Hp gene product is proposed to be an inhibitor of the state of responsiveness amplification for responses controlled by this relatively stable Pfr species.     

Hybrid Bis-Histidine Phenanthroline-Based Ligands to Lessen Aβ-Bound Cu ROS Production: An Illustration of Cu(I) Significance

We here report the synthesis of three new hybrid ligands built around the phenanthroline scaffold and encompassing two histidine-like moieties: phenHH, phenHGH and H’phenH’, where H correspond to histidine and H’ to histamine. These ligands were designed to capture Cu(I/II) from the amyloid-β peptide and to prevent the formation of reactive oxygen species produced by amyloid-β bound copper in presence of physiological reductant (e.g., ascorbate) and dioxygen. The amyloid-β peptide is a well-known key player in Alzheimer’s disease, a debilitating and devasting neurological disorder the mankind has to fight against. The Cu-Aβ complex does participate in the oxidative stress observed in the disease, due to the redox ability of the Cu(I/II) ions. The complete characterization of the copper complexes made with phenHH, phenHGH and H’phenH’ is reported, along with the ability of ligands to remove Cu from Aβ, and to prevent the formation of reactive oxygen species catalyzed by Cu and Cu-Aβ, including in presence of zinc, the second metal ions important in the etiology of Alzheimer’s disease. The importance of the reduced state of copper, Cu(I), in the prevention and arrest of ROS is mechanistically described with the help of cyclic voltammetry experiments.     

Return current instability and its effects on beam-plasma system

The return current induced in a plasma by a relativisitc electron beam generates a new electron-ion two-stream instability (return current instability). Although the effect of these currents on the beam-plasma e-e instability is negligible, there exists a range of wave numbers which is unstable only to return current (RC) instability and not to e-e instability. The electromagnetic waves propagating along the direction of the external magnetic field, in which the plasma is immersed, are stabilized by these currents but the e.m. waves with frequencies,ω ²≪Ω _e ² ≪ω _pe ² (Ω _e andω _pe being cyclotron and plasma frequency for the electrons of the plasma respectively) propagating transverse to the magnetic field get destabilized. Heuristic estimates of plasma heating, due to RC instability and due to decay of ion-acoustic turbulence generated by the return current, are made. The fastest time scale on which the return current delivers energy to the plasma due to the scattering of ion-sound waves by the electrons can be ∼ω _pi ⁻¹ (ω _pi being the plasma frequency for the ions).     

The synthesis and spectroscopic properties of 3-(2′,4′-Xylyl)-1H,3H-quinazoline-2,4-diones

The synthesis of 3-(2′,4′-xylyl)-1H,3H-quinazoline-2,4-diones ( 1a, 9a-j ) has been accomplished. Their pmr and ir spectra data for all compounds are presented.     

Fructose-6-phosphate aldolases as versatile biocatalysts for nitrocyclitol syntheses

Efficient and stereoselective polyhydroxylated nitrocyclitol syntheses were performed via biocatalysed aldol reactions. The key step was based on a one-pot/one-enzyme cascade reaction process where two reactions occur: aldolase-catalysed aldolisation and spontaneous intramolecular nitroaldolisation. The synthetic methodology was investigated using fructose-6-phosphate aldolase A129S for the synthesis of known nitrocyclitols. Improvements were obtained which involved less steps and increased yields. Several new nitrocyclitols were also prepared using hydroxyacetone (HA) as the donor and FSA wt. From nitrocyclitol stereochemical analyses, the intramolecular nitro-Henry reaction stereoselectivity was dependent on the donor substrate used, HA or dihydroxyacetone (DHA). Whereas DHA provided two stereoisomers, four were obtained using HA.     

Bi3+/M2+ oxyphosphate: a continuous series of polycationic species from the 1D single chain to the 2D planes. Part 2: Crystal structure of three original structural types showing a combination of new ribbonlike polycations

With the assistance of structural models deduced from the high-resolution electron microscope (HREM) investigation presented in Part 1 of this work, three new structural types were pointed out in Bi2O3-MO-P2O5 ternary systems. Their crystal structures are built on the arrangement of 2D polycationic ribbons formed of edge-sharing O(Bi,M)4 tetrahedra and isolated by PO4 groups. Prior to this study, materials with ribbons up to n = 3 tetrahedra wide have been discovered. The original structures presented here display longer n = 4-6 cases, which suggests a possible continuous series of polycationic entities that range from the single chain (one tetrahedron wide) to the infinite [Bi2O2]2+ Aurivillius layer. The ribbons with n > 3 show strong structural modifications that are able to bring a good ribbon-phosphate cohesion. In addition to these fascinating structural results, this work fully confirms the validity of the decoding established from HREM images of a single crystallite in inhomogeneous mixtures.     

Crossover to the Stochastic Burgers Equation for the WASEP with a Slow Bond

We consider the weakly asymmetric simple exclusion process in the presence of a slow bond and starting from the invariant state, namely the Bernoulli product measure of parameter \({\rho \in (0,1)}\). The rate of passage of particles to the right (resp. left) is \({\frac{1}{2} + \frac{a}{2n^{\gamma}}}\) (resp. \({\frac{1}{2} - \frac{a}{2n^{\gamma}}}\)) except at the bond of vertices \({\{-1,0\}}\) where the rate to the right (resp. left) is given by \({\frac{\alpha}{2n^\beta} + \frac{a}{2n^{\gamma}}}\) (resp. \({\frac{\alpha}{2n^\beta}-\frac{a}{2n^{\gamma}}}\)). Above, \({\alpha > 0}\), \({\gamma \geq \beta \geq 0}\), \({a\geq 0}\). For \({\beta < 1}\), we show that the limit density fluctuation field is an Ornstein–Uhlenbeck process defined on the Schwartz space if \({\gamma > \frac{1}{2}}\), while for \({\gamma = \frac{1}{2}}\) it is an energy solution of the stochastic Burgers equation. For \({\gamma \geq \beta =1}\), it is an Ornstein–Uhlenbeck process associated to the heat equation with Robin’s boundary conditions. For \({\gamma \geq \beta > 1}\), the limit density fluctuation field is an Ornstein–Uhlenbeck process associated to the heat equation with Neumann’s boundary conditions.     

Mining performance data through nonlinear PCA with optimal scaling

Performance data are usually collected in order to build well‐defined performance indicators. Since such data may conceal additional information, which can be revealed by secondary analysis, we believe that mining of performance data may be fruitful. We also note that performance databases usually contain both qualitative and quantitative variables for which it may be inappropriate to assume some specific (multivariate) underlying distribution. Thus, a suitable technique to deal with these issues should be adopted. In this work, we consider nonlinear principal component analysis (PCA) with optimal scaling, a method developed to incorporate all types of variables, and to discover and handle nonlinear relationships. The reader is offered a case study in which a student opinion database is mined. Though generally gathered to provide evidence of teaching ability, they are exploited here to provide a more general performance evaluation tool for those in charge of managing universities. We show how nonlinear PCA with optimal scaling applied to student opinion data enables users to point out some strengths and weaknesses of educational programs and services within a university. Copyright © 2009 John Wiley & Sons, Ltd.     

Transport phenomena in a partially lonized Lorentzian magnetoplasma

Some transport coefficients are evaluated for a homogeneous, partially ionized Lorentzian plasma in the presence of a uniform external magnetic field. The electronion collisions are taken into account by means of the modified Fokker-Planck equation and the electron-neutral collision frequency, ν_en is taken as velocity (ω) dependent or velocity independent, depending on the energy range under consideration. The variation of the transport coefficients with magnetic field is determined for ν_en ∝ ω^s (s being a positive or negative integer) and one finds that qualitatively this behavior does not change by changing either the collision frequency or the velocity dependence of the collision frequency; however for weak magnetic fields the magnitudes of these transport coefficients increase with the decrease in ν_en or s, whereas for strong magnetic fields the transverse components of the transport coefficients decrease and the Hall components tend to saturate with the decrease of either the collision frequency or s.     

Well management in the North Sea

The purpose of this paper is to describe a planning model for the management of approximately 130 petroleum-producing wells in the North Sea. The objective is to form a better basis for the decisions about which wells to produce from and which to shut down during a period. Every well is dealt with individually as the production potential and chemical composition are different. The total flow consists of six saleable components: gas, four NGL products, and oil. The production may be curtailed due to the capacities of the platforms, gathering centre, pipelines and refinery plants. The total gas production is available for fulfilling the gas contracts, injecting the gas into the reservoirs or using the gas as fuel. There exist contracts for some of the NGL products, while the rest of the NGL products and oil are sold on the free market. The well-management model is solved by means of a standard mathematical programming code, and computational results are given for a planning problem with four different data sets.