At4g24160, a Soluble Acyl-Coenzyme A-Dependent Lysophosphatidic Acid Acyltransferase

Human CGI-58 (for comparative gene identification-58) and YLR099c, encoding Ict1p in Saccharomyces cerevisiae, have recently been identified as acyl-CoA-dependent lysophosphatidic acid acyltransferases. Sequence database searches for CGI-58 like proteins in Arabidopsis (Arabidopsis thaliana) revealed 24 proteins with At4g24160, a member of the alpha/beta-hydrolase family of proteins being the closest homolog. At4g24160 contains three motifs that are conserved across the plant species: a GXSXG lipase motif, a HX4D acyltransferase motif, and V(X)(3)HGF, a probable lipid binding motif. Dendrogram analysis of yeast ICT1, CGI-58, and At4g24160 placed these three polypeptides in the same group. Here, we describe and characterize At4g24160 as, to our knowledge, the first soluble lysophosphatidic acid acyltransferase in plants. A lipidomics approach revealed that At4g24160 has additional triacylglycerol lipase and phosphatidylcholine hydrolyzing enzymatic activities. These data establish At4g24160, a protein with a previously unknown function, as an enzyme that might play a pivotal role in maintaining the lipid homeostasis in plants by regulating both phospholipid and neutral lipid levels.

Stable Crystalline Salts of Haloperidol: A Highly Water-Soluble Mesylate Salt

Haloperidol, an antipsychotic drug, was screened for new solid crystalline phases using high throughput crystallization in pursuit of solubility improvement. Due to the highly basic nature of the API, all the solid forms with acids were obtained in the form of salts. Eleven crystalline salts in the form of oxalate (1:1), benzoate (1:1), salicylate (1:1 and 1:2), 4-hydroxybenzoate (1:1), 4-hydroxybenzoate ethyl acetate solvate (1:1:1), 3,4-dihydroxybenzoate (1:1), 3,5-dihydroxybenzoate (1:1), mesylate (1:1), besylate (1:1), and tosylate (1:1) salt were achieved. There is an insertion of carboxylate or sulfonate anion into the hydrogen bonding pattern of haloperidol. The salts with the aliphatic carboxylic acids were found to be more prone to form salt hydrates compared with aromatic carboxylate salts. All the salts were subjected to solubility measurement in water at neutral pH. There was no direct correlation observed between the solubility of the salt and its coformer. All the salts are stable at room temperature as well as after 24 h slurry experiment except the oxalate salt, which showed an unusual phase transformation from its hydrated form to the anhydrous form. A structureproperty relationship was examined to analyze the solubility behavior of the solid forms.

Preparation of lamellar and hexagonal forms of mesoporous silica and zirconiaby the neutral amine route: lamellar-hexagonal transformation in the solid state

The chain length of the surfactant and the solvent composition are two of the factors that determine whether the lamellar or the hexagonal form of mesoporous SiO2 (or ZrO2) is formed by the neutral amine route; a lamellar-hexagonal transformation occurs on removal of the amine from the former.

A soluble preparation from developing groundnut seeds (Arachis hypogaea) catalyzes de novo synthesis of long chain fatty acids

A 100,000 x g supernatant fraction prepared from developing groundnut seeds (30-35 days after flowering) catalyzed the synthesis of fatty acids from [l-14C]acetate at a rate of 120nmoles of acetate incorporated per hr per gram fresh weight of tissue. 90% of this incorporated label was associated with fatty acids. The major fatty acids formed were stearic- (77%) and palmitic acids (14%) with 4% of oleic acid. The fatty acid synthetase activity was stable when stored at 0-4 degrees C for at least fifteen days. It is concluded from these results that acetyl-coA carboxylase and all the enzymes of fatty acid synthetase from developing groundnut seeds are soluble.

Metal-Ion-Dependent Oxidative DNA Cleavage by Transition Metal Complexes of a New Water-Soluble Salen Derivative

A new water-soluble, salen [salen = bis(salicylidene) ethylenediamine]-based ligand, 3 was developed. Two of the metal complexes of this ligand, i.e., 3a, [Mn(III)] and 3b, [Ni(II)], in the presence of cooxidant magnesium monoperoxyphthalate (MMPP) cleaved plasmid DNA pTZ19R efficiently and rapidly at a concentration similar to 1 mu M. In contrast, under comparable conditions, other metal complexes 3c, [Cu(II)] or 3d, [Cr(III)] could not induce any significant DNA nicking. The findings with Ni(II) complex suggest that the DNA cleavage processes can be modulated by the disposition of charges around the ligand.

Probing the Neutral Edge Modes in Transport across a Point Contact via Thermal Effects in the Read-Rezayi Non-Abelian Quantum Hall States

Non-Abelian quantum Hall states are characterized by the simultaneous appearance of charge and neutral gapless edge modes, with the structure of the latter being intricately related to the existence of bulk quasiparticle excitations obeying non-Abelian statistics. Here we propose a scenario for detecting the neutral modes by having two point contacts in series separated by a distance set by the thermal equilibration length of the charge mode. We show that by using the first point contact as a heating device, the excess charge noise measured at the second point contact carries a nontrivial signature of the presence of the neutral mode. We also obtain explicit expressions for the thermal conductance and corresponding Lorentz number for transport across a quantum point contact between two edges held at different temperatures and chemical potentials.

Adsorption isotherms for neutral organic compounds-A hierarchy in modelling: Part II

A two-state model allowing for size disparity between the solvent and the adsorbate is analysed to derive the adsorption isotherm for electrosorption of organic compounds. Explicity, the organic adsorbate is assumed to occupy "n" lattice sites at the interface as compared to "one" by the solvent. The model parameters are the respective permanent and induced dipole moments apart from the nearest neighbour distance. The coulombic interactions due to permanent and induced dipole moments, discreteness of charge effects, and short-range and specific substrate interactions have all been incorporated. The adsorption isotherm is then derived using mean field approximation (MFA) and is found to be more general than the earlier multi-site versions of Bockris and Swinkels, Mohilner et al., and Bennes, as far as the entropy contributions are concerned. The role of electrostatic forces is explicity reflected in the adsorption isotherm via the Gibbs energy of adsorption term which itself is a quadratic function of the electrode charge-density. The approximation implicit in the adsorption isotherm of Mohilner et al. or Bennes is indicated briefly.

Adsorption isotherms for neutral organic compounds-A hierarchy in modelling: Part III

A simple three-state model permitting two different configurational states for the solvent, together with one for the organic adsorbate, is analysed to derive the adsorption isotherm. The implications of this model regarding pseudo-two-state and pseudo-Frumkin adsorption isotherms are indicated. A critique of the earlier theory of Bockris, Devanathan and Müller is presented in brief.

Adsorption isitherms for neutral organic compounds-A hierarchy in modelling: Part IV. Charge of maximum adsorption-Statistical mechanical basis

The charge at which adsorption of orgamc compounds attains a maximum ( \sigma MAX M) at an electrochenucal interface is analysed using several multi-state models in a hierarchical manner The analysis is based on statistical mechamcal results for the following models (A) two-state site parity, (B) two-state muhl-slte, and (C) three-state site parity The coulombic interactions due to permanent and reduced dipole effects (using mean field approximation), electrostatic field effects and specific substrate interactions have been taken into account. The simplest model in the hierarchy (two-state site parity) yields the exphcit dependence of ( \sigma MAX M) on the permanent dipole moment, polarizability of the solvent and the adsorbate, lattice spacing, effective coordination number, etc Other models in the baerarchy bring to hght the influence of the solvent structure and the role of substrate interactions, etc As a result of this approach, the "composition" of oM.x m terms of the fundamental molecular constants becomes clear. With a view to use these molecular results to maxamum advantage, the derived results for ( \sigma MAX M) have been converted into those involving experimentally observable parameters lake Co, C 1, E N, etc Wherever possible, some of the earlier phenomenologlcal relations reported for ( \sigma MAX M), notably by Parsons, Damaskm and Frumkln, and Trasattl, are shown to have a certain molecular basis, vlz a simple two-state sate panty model.As a corollary to the hxerarcbacal modelling, \sigma MAX M and the potential corresponding to at (Emax) are shown to be constants independent of 0max or Corg for all models The lmphcatlon of our analysis f o r OmMa x with respect to that predicted by the generalized surface layer equation (which postulates Om~ and Ema x varlaUon with 0) is discussed in detail Finally we discuss an passing o M. and the electrosorptlon valency an this context.

Adsorption isotherms for neutral organic compounds - A hierarchy in modelling: Part V. Models for the inner layer potential difference in the presence of dipolar adsorption

The relations for the inner layer potential &fference (E) in the presence of adsorbed orgamc molecules are derived for three hterarchlcal models, m terms of molecular constants like permanent &pole moments, polarlzablhtles, etc It is shown how the experimentally observed patterns of the E vs 0 plots (hnear m all ranges of $\sigma^M$, non-linear in one or both regions of o M, etc ) can be understood in a serm-quantltatlve manner from the simplest model in our hierarchy, viz the two-state site panty version Two-state multi-site and three-state (sxte panty) models are also analysed and the slope (3E/80),,M tabulated for these also The results for the Esm-Markov effect are denved for all the models and compared with the earlier result of Parsons. A comparison with the GSL phenomenologlcal equation is presented and its molecular basis, as well as the hmltatlons, is analysed. In partxcular, two-state multa-slte and three-state (site panty) models yield E-o M relations that are more general than the "umfied" GSL equation The posslblhty of vaewlng the compact layer as a "composite medium" with an "effective dlelectnc constant" and obtaimng novel phenomenological descnptions IS also indicated.

Estimation of cosmological parameters from neutral hydrogen observations of the post-reionization epoch

The emission from neutral hydrogen (HI) clouds in the post-reionization era (z <= 6), too faint to be individually detected, is present as a diffuse background in all low frequency radio observations below 1420MHz. The angular and frequency fluctuations of this radiation (similar to 1 mK) are an important future probe of the large-scale structures in the Universe. We show that such observations are a very effective probe of the background cosmological model and the perturbed Universe. In our study we focus on the possibility of determining the redshift-space distortion parameter beta, coordinate distance r(nu), and its derivative with redshift r(nu)('). Using reasonable estimates for the observational uncertainties and configurations representative of the ongoing and upcoming radio interferometers, we predict parameter estimation at a precision comparable with supernova Ia observations and galaxy redshift surveys, across a wide range in redshift that is only partially accessed by other probes. Future HI observations of the post-reionization era present a new technique, complementing several existing ones, to probe the expansion history and to elucidate the nature of the dark energy.

A Front end Switched Rectifier DC Source for Neutral Point Balancing of A NPC Three-Level Inverter for The Full Modulation Range

A switched DC voltage three level NPC is proposed in this paper to eliminate capacitor balancing problems in conventional three-level Neutral Point Clamped (NPC) inverter. The proposed configuration requires only one DC link with a voltage V-dc/2, where V-dc is the DC link voltage in a onventional NPC inverter. To get rated DC link voltage (V-dc), the voltage source is alternately onnected in parallel to one of the two series capacitors using two switches and two diodes with device voltage rating of V-dc/2. The frequency at which the voltage source is switched is independent and will not affect the operation of NPC inverter. The switched voltage source in this configuration balances the capacitors automatically. The proposed configuration can also be used as a conventional two level inverter in lower modulation range, thereby increases the reliability of the drive system. A space vector based PWM scheme is used to verify this proposed topology.

Studies on the purification of banana polyphenoloxidase

Studies on the extractability of polyphenoloxidase (PPO) from the pulp of five banana cultivars revealed a varietal difference in the nature of binding of the PPO in the cell, with the enzyme being entirely in the soluble fraction in one and partly associated with the cell wall in others, necessitating use of a detergent to release it from the latter. Partial purification by acetone precipitation and chromatography using a DEAE-cellulose column yielded two major fractions DE-I and DE-II with purifications of 4- and 16·3-fold and activity recoveries of 38·2 and 43·3% respectively. Further gel filtration of the two fractions on a Sephadex G-100 column improved the purifications to 44- and 50-fold respectively with full activity recovery. Polyacrylamide gel electrophoretic studies showed the two fractions to be composed of isoenzymes differing in pattern. The purified enzyme showed maximum absorption at 275 nm.

A gravimetric procedure for the determination of wet precipitated sulphur, dissolved sulphur, soluble sulphides and hydrogen sulphide

Elemental sulphur (in wet precipitated form or dissolved in organic solvents) and hydrogen sulphide have been determined gravimetrically at room temperature by conversion into copper sulphide by elemental copper in presence of an organic solvent such as benzene or acetonitrile. Any solvent in which sulphur is soluble can be used. The black copper sulphide formed can be weighed or determined iodometrically. Analysis indicates the black compound to be Cu1.8S. This room temperature method is a versatile one-step procedure sensitive to microgram or macro amounts of sulphur. It has been used for determining the solubility of sulphur in tetrahydrofuran and dioxan. The apparent heat of solution indicates that sulphur dissolves in these solvents without any marked solute—solvent interactions.

Alfven surface waves along a cylindrical plasma column surrounded by neutral gas

The dispersion characteristics of Alfven surface waves along a cylindrical plasma column insulated by a neutral gas are discussed. There is no qualitative change in the characteristic curves below the critical magnetic field, given by vA approximately=s, as compared to the propagation of surface waves along the plasma-plasma interface. For magnetic fields above this critical value, there exists a cut-off wave number kc, which depends upon the azimuthal wave number, the radius of the cylinder, the strength of the magnetic field above the critical value and the gas pressure, such that surface waves do not exist for k