Heterologous expression of P5CS gene in chickpea enhances salt tolerance without affecting yield

Vigna Delta(1)-pyrroline-5-carboxylate synthetase (P5CS) cDNA was transferred to chickpea (Cicer arietinum L.) cultivar Annigeri via Agrobacterium tumefaciens mediated transformation. Following selection on hygromycin and regeneration, 60 hygromycin-resistant plants were recovered. Southern blot analysis of five fertile independent lines of T0 and T1 generation revealed single and multiple insertions of the transgene. RT-PCR and Western blot analysis of T0 and T1 progeny demonstrated that the P5CS gene is expressed and produced functional protein in chickpea. T1 transgenic lines accumulated higher amount of proline under 250 mM NaCl compared to untransformed controls. Higher accumulation of Na(+) was noticed in the older leaves but negligible accumulation in seeds of T1 transgenic lines as compared to the controls. Chlorophyll stability and electrolyte leakage indicated that proline overproduction helps in alleviating salt stress in transgenic chickpea plants. The T1 transgenics lines were grown to maturity and set normal viable seeds under continuous salinity stress (250 mM) without any reduction in plant yield in terms of seed mass.

Brillouin Scattering Investigation of Solvation Dynamics in Succinonitrile-Lithium Salt Plastic Crystalline Electrolytes

Temperature dependent Brillouin scattering studies have been performed to ascertain the influence of solvent dynamics on ion-transport in succinonitrile-lithium salt plastic crystalline electrolytes. Though very rarely employed, we observe that Brillouin spectroscopy is an invaluable tool for investigation of solvent dynamics. Analysis of various acoustic (long wavelength) phonon modes observed in the Brillouin scattering spectra reveal the influence of trans-gauche isomerism and as well as ion-association effects on ion transport. Although pristine SN and dilute SN-LiClO(4) samples show only the bulk longitudinal-acoustic (LA) mode, concentrated SN-LiClO(4) (similar to 0.3-1 M) electrolytes display both the bulk LA mode as well as salt induced brillouin modes at ambient temperature. The appearance of more than one brillouin mode is attributed to the scattering of light from regions with different compressibilities (''compactness''). Correspondingly, these modes show a large decrease in the full width at half-maximum (abbreviated as nu(f)) as the temperature decreases. Anomalous temperature dependent behavior of nu(f) with addition of salt could be attributed to the presence of disorder or strong coupling with a neighbor. The shape of the spectrum was evaluated using a Lorentzian and Fano line shape function depending on the nature and behavior of the Brillouin modes.

Thermodynamic properties of Ln-O (Ln = La, Pr, Nd) solid solutions and their deoxidation by molten salt electrolysis

The lanthanide metals lanthanum, praseodymium and neodymium containing 2,200, 2,600, 1,850 mass ppm oxygen, respectively, were deoxidized to 20-30 ppm level at 1,073 K by an electrochemical method. The metal to be deoxidized was used as the cathode in an electrolysis cell which consisted of a graphite anode and molten CaCl2 electrolyte. The calcium metal produced at the cathode by electrolysis effectively deoxidized the lanthanide metal. Calcium oxide produced by deoxidation, dissolved in the melt. The liberation of carbon monoxide/dioxide at the anode was found to prevent accumulation of oxygen in the melt. For a quantitative discussion of the limits of deoxidation achievable by this technique, a thermodynamic investigation of the lanthanide-oxygen (Ln-O ; Ln = La, Pr, Nd) solid solutions was conducted. The lanthanide metal, yttrium and titanium samples were immersed in calcium-saturated CaCl2 melt, containing a small quantity of dissolved CaO, at 1,093 K. The oxygen potential of the melt and the Ln-O solid solutions were obtained from the oxygen content of yttrium samples at equilibrium, and the known thermodynamic properties of yttrium-oxygen solid solution. The results were confirmed by using Y/Y2O3 equilibrium to control the oxygen potential of the molten salt reservoir. The oxygen affinity of the metals was found to decrease in the order : Y > Ti > Nd > Pr > La. The deoxidation results are consistent with the thermodynamic properties of the RE-O solid solutions.

IN-VITRO CYTOTOXICITY AND CELL CYCLE ANALYSIS OF TWO NOVEL BIS-1, 2, 4-TRIAZOLE DERIVATIVES: 1,4-BIS[5-(5-MERCAPTO-1,3,4-OXADIAZOL-2-yl-METHYL)-THIO-4-(p-TOLYL)-1, 2,4-TRIAZOL-3-yl]-BUTANE (MNP-14) AND 1,4-BIS[5-(CARBETHOXY-METHYL)-THIO-4-(p-ETHOXY PHENYL)-1,2,4-TRIAZOL-3-yl]-BUTANE (MNP-16)

In the present study, we have tested the cytotoxic and DNA damage activity of two novel bis-1,2,4 triazole derivatives, namely 1,4-bis[5-(5-mercapto-1,3,4-oxadiazol-2-yl-methyl)-thio4-(p-tolyl)-1,2 ,4-triazol-3-yl]-butane (MNP-14) and 1,4-bis[5-(carbethoxy-methyl)-thio-4-(p-ethoxy phenyl) -1,2,4-triazol-3-yl]-butane (MNP-16). The effect of these molecules on cellular apoptosis was also determined. The in-vitro cytotoxicity was evaluated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay as well as Trypan blue dye exclusion methods against human acute lymphoblastic leukemia (MOLT4) and lung cancer cells (A549). Our results showed that MNP-16 induced significant cytotoxicity (IC50 of 3-5 mu M) compared with MNP-14. The cytotoxicity induced by MNP-16 was time and concentration dependent. The cell cycle analysis by flow cytometry (fluorescence-activated cell sorting [FACS]) revealed that though there was a significant increase in the apoptotic population (sub-G1 phase) with an increased concentration of MNP-14 and 16, there was no cell cycle arrest. Further, the comet assay results indicated considerable DNA

Ion Transport in Liquid Salt Solutions with Oxide Dispersions:``Soggy Sand'' Electrolytes

``Soggy sand'' electrolyte, which essentially consists of oxide dispersions in nonaqueous liquid salt solutions, comprises an important class of soft matter electrolytes. The ion transport mechanism of soggy sand electrolyte is complex. The configuration of particles in the liquid solution has been observed to depend in a nontrivial manner on various parameters related to the oxide (concentration, size, surface chemistry) and solvent (dielectric constant, viscosity) as well as time. The state of the particles in solution not only affects ionic conductivity but also effectively the mechanical and electrochemical properties of the solid liquid composite. Apart from comprehensive understanding of the underlying phenomena that govern ion transport, which will benefit design of better electrolytes, the problem has far-reaching implications in diverse fields such as catalysis, colloid chemistry, and biotechnology.

Gel Sculpture: Moldable, Load-Bearing and Self-Healing Non-Polymeric Supramolecular Gel Derived from a Simple Organic Salt

An easy access to a library of simple organic salts derived from tert-butoxycarbonyl (Boc)-protected L-amino acids and two secondary amines (dicyclohexyl- and dibenzyl amine) are synthesized following a supramolecular synthon rationale to generate a new series of low molecular weight gelators (LMWGs). Out of the 12 salts that we prepared, the nitrobenzene gel of dicyclohexylammonium Boc-glycinate (GLY.1) displayed remarkable load-bearing, moldable and self-healing properties. These remarkable properties displayed by GLY.1 and the inability to display such properties by its dibenzylammonium counterpart (GLY.2) were explained using microscopic and rheological data. Single crystal structures of eight salts displayed the presence of a 1D hydrogen-bonded network (HBN) that is believed to be important in gelation. Powder X-ray diffraction in combination with the single crystal X-ray structure of GLY.1 clearly established the presence of a 1D hydrogen-bonded network in the xerogel of the nitrobenzene gel of GLY.1. The fact that such remarkable properties arising from an easily accessible (salt formation) small molecule are due to supramolecular (non-covalent) interactions is quite intriguing and such easily synthesizable materials may be useful in stress-bearing and other applications.

Influence of Bottom Bubbling Rate on Formation of Metal Emulsion in Al-Cu Alloy and Molten Salt System

In steel refining process, an increase of interfacial area between the metal and slag through the metal droplets emulsified into the slag, so-called ``metal emulsion'', is one prevailing view for improving the reaction rate. The formation of metal emulsion was experimentally evaluated using Al-Cu alloy as metal phase and chloride salt as slag phase under the bottom bubbling condition. Samples were collected from the center of the salt phase in the container. Large number of metal droplets were separated from the salt by dissolving it into water. The number, surface area, and weight of the droplets increased with the gas flow rate and have local maximum values. The formation and sedimentation rates of metal droplets were estimated using a mathematical model. The formation rate increased with the gas flow rate and has a local maximum value as a function of gas flow rate, while the sedimentation rate is independent of the gas flow rate under the bottom bubbling condition. Three types of formation mode of metal emulsion, which occurred by the rupture of metal film around the bubble, were observed using high speed camera. During the process, an elongated column covered with metal film was observed with the increasing gas flow rate. This elongated column sometimes reached to the top surface of the salt phase. In this case, it is considered that fine droplets were not formed and in consequence, the weight of metal emulsion decreased at higher gas flow rate.

Modeling of Ascending/Descending Velocity of Metal Droplet Emulsified in Pb-Salt System

Metal-slag emulsion is an important process to enhance the reaction rate between the two phases; thus, it improves the heat and mass transfer of the process significantly. Various experimental studies have been carried out, and some system specific relations have been proposed by various investigators. A unified, theoretical study is lacking to model this complex phenomenon. Therefore, two simple models based on fundamental laws for metal droplet velocity (both ascending and descending) and bubble velocity, as well as its position at any instant of time, have been proposed. Analytical solutions have been obtained for the developed equations. Analytical solutions have been verified for the droplet velocity, traveling time, and size distribution in slag phase by performing high-temperature experiments in a Pb-salt system and comparing the obtained data with theory. The proposed model has also been verified with published experimental data for various liquid systems with a wide range of physical properties. A good agreement has been found between the analytical solution and the experimental and published data in all cases.

Ionic conductivity of bis(2-cyanoethyl) ether-lithium salt and poly(propylether imine)-lithium salt liquid electrolytes

We report here a multiple-nitrile based lithium-salt liquid electrolyte. The ionic conductivity of poly (propyl ether imine) (abbreviated as PETIM) lithium salt dendrimer liquid electrolyte was observed to be a function of dendrimer generation number, n=0 (monomer)-3. While the highest room temperature ionic conductivity value (similar to 10(-1) Sm-1) was recorded for the bis-2cyanoethyl ether monomer (i.e. zeroth generation; G(0)-CN), conductivity decreased progressively to lower values (similar to 10(-3) Sm-1) with increase in generation number (G(1)-CN -> G(3)-CN). The G(0)-CN and higher dendrimer generations showed high thermal stability (approximate to 150 to 200 degrees C), low moisture sensitivity and tunable viscosity (similar to 10(-2) (G(0)-CN) to 3 (G(3)-CN) Pa s). The linker ether group was found to be crucial for ion transport and also eliminated a large number of detrimental features, chiefly moisture sensitivity, chemical instability associated typically with prevalent molecular liquid solvents. Based on the combination of several beneficial physicochemical properties, we presently envisage that the PETIM dendrimers especially the G(0)-CN electrolytes hold promise as electrolytes in electrochemical devices such as lithium-ion batteries.

Effect of high gold salt concentrations on the size and polydispersity of gold nanoparticles prepared by an extended Turkevich-Frens method

The Turkevich-Frens synthesis starting conditions are expanded, ranging the gold salt concentrations up to 2 mM and citrate/gold(III) molar ratios up to 18:1. For each concentration of the initial gold salt solution, the citrate/gold(III) molar ratios are systematically varied from 2:1 to 18:1 and both the size and size distribution of the resulting gold nanoparticles are compared. This study reveals a different nanoparticle size evolution for gold salt solutions ranging below 0.8 mM compared to the case of gold salt solutions above 0.8 mM. In the case of Au3+]<0.8 mM, both the size and size distribution vary substantially with the citrate/gold(III) ratio, both displaying plateaux that evolve inversely to Au3+] at larger ratios. Conversely, for Au3+]>= 0.8 mM, the size and size distribution of the synthesized gold nanoparticles continuously rise as the citrate/gold(III) ratio is increased. A starting gold salt concentration of 0.6 mM leads to the formation of the most monodisperse gold nanoparticles (polydispersity index<0.1) for a wide range of citrate/gold(III) molar ratios (from 4:1 to 18:1). Via a model for the formation of gold nanoparticles by the citrate method, the experimental trends in size could be qualitatively predicted:the simulations showed that the destabilizing effect of increased electrolyte concentration at high initial Au3+] is compensated by a slight increase in zeta potential of gold nanoparticles to produce concentrated dispersion of gold nanoparticles of small sizes.

Unusual Salt-Induced Color Modulation through Aggregation-Induced Emission Switching of a Bis-cationic Phenylenedivinylene-Based pi Hydrogelator

The synthesis, hydrogelation, and aggregation-induced emission switching of the phenylenedivinylene bis-N-octyl pyridinium salt is described. Hydrogelation occurs as a consequence of pi-stacking, van der Waals, and electrostatic interactions that lead to a high gel melting temperature and significant mechanical properties at a very low weight percentage of the gelator. A morphology transition from fiber-to-coil-to-tube was observed depending on the concentration of the gelator. Variation in the added salt type, salt concentrations, or temperature profoundly influenced the order of aggregation of the gelator molecules in aqueous solution. Formation of a novel chromophore assembly in this way leads to an aggregation-induced switch of the emission colors. The emission color switches from sky blue to white to orange depending upon the extent of aggregation through mere addition of external inorganic salts. Remarkably, the salt effect on the assembly of such cationic phenylenedivinylenes in water follow the behavior predicted from the well-known Hofmeister effects. Mechanistic insights for these aggregation processes were obtained through the counterion exchange studies. The aggregation-induced emission switching that leads to a room-temperature white-light emission from a single chromophore in a single solvent (water) is highly promising for optoelectronic applications.

Phospholipid Mediated Activation of Calcium Dependent Protein Kinase 1 (CaCDPK1) from Chickpea: A New Paradigm of Regulation

Phospholipids, the major structural components of membranes, can also have functions in regulating signaling pathways in plants under biotic and abiotic stress. The effects of adding phospholipids on the activity of stress-induced calcium dependent protein kinase (CaCDPK1) from chickpea are reported here. Both autophosphorylation as well as phosphorylation of the added substrate were enhanced specifically by phosphatidylcholine and to a lesser extent by phosphatidic acid, but not by phosphatidylethanolamine. Diacylgylerol, the neutral lipid known to activate mammalian PKC, stimulated CaCDPK1 but at higher concentrations. Increase in V-max of the enzyme activity by these phospholipids significantly decreased the K-m indicating that phospholipids enhance the affinity towards its substrate. In the absence of calcium, addition of phospholipids had no effect on the negligible activity of the enzyme. Intrinsic fluorescence intensity of the CaCDPK1 protein was quenched on adding PA and PC. Higher binding affinity was found with PC (K-1/2 = 114 nM) compared to PA (K-1/2 = 335 nM). We also found that the concentration of PA increased in chickpea plants under salt stress. The stimulation by PA and PC suggests regulation of CaCDPK1 by these phospholipids during stress response.

Simulations reveal that the HIV-1 gp120-CD4 complex dissociates via complex pathways and is a potential target of the polyamidoamine (PAMAM) dendrimer

The polyamidoamine (PAMAM) dendrimer prevents HIV-1 entry into target cells in vitro. Its mechanism of action, however, remains unclear and precludes the design of potent dendrimers targeting HIV-1 entry. We employed steered molecular dynamics simulations to examine whether the HIV-1 gp120-CD4 complex is a target of PAMAM. Our simulations mimicked single molecule force spectroscopy studies of the unbinding of the gp120-CD4 complex under the influence of a controlled external force. We found that the complex dissociates via complex pathways and defies the standard classification of adhesion molecules as catch and slip bonds. When the force loading rate was large, the complex behaved as a slip bond, weakening gradually. When the loading rate was small, the complex initially strengthened, akin to a catch bond, but eventually dissociated over shorter separations than with large loading rates. PAMAM docked to gp120 and destabilized the gp120-CD4 complex. The rupture force of the complex was lowered by PAMAM. PAMAM disrupted salt bridges and hydrogen bonds across the gp120-CD4 interface and altered the hydration pattern of the hydrophobic cavity in the interface. In addition, intriguingly, PAMAM suppressed the distinction in the dissociation pathways of the complex between the small and large loading rate regimes. Taken together, our simulations reveal that PAMAM targets the gp120-CD4 complex at two levels: it weakens the complex and also alters its dissociation pathway, potentially inhibiting HIV-1 entry.

New rock salt-related oxides Li3M2RuO6 (M=Co, Ni): Synthesis, structure, magnetism and electrochemistry

We describe the synthesis, crystal structure, magnetic and electrochemical characterization of new rock salt-related oxides of formula, Li3M2RuO6 (M=Co, Ni). The M=Co oxide adopts the LiCoO2 (R-3m) structure, where sheets of LiO6 and (Co-2/Ru)O-6 octahedra are alternately stacked along the c-direction. The M=Ni oxide also adopts a similar layered structure related to Li2TiO3, where partial mixing of Li and Ni/Ru atoms lowers the symmetry to monoclinic (C2/c). Magnetic susceptibility measurements reveal that in Li3Co2RuO6, the oxidation states of transition metal ions are Co3+ (S=0), Co2+ (S=1/2) and Ru4+ (S=1), all of them in low-spin configuration and at 10 K, the material orders antiferromagnetically. Analogous Li3Ni2RuO6 presents a ferrimagnetic behavior with a Curie temperature of 100 K. The differences in the magnetic behavior have been explained in terms of differences in the crystal structure. Electrochemical studies correlate well with both magnetic properties and crystal structure. Li-transition metal intermixing may be at the origin of the more impeded oxidation of Li3Ni2RuO6 when compared to Li3CO2RuO6. Interestingly high first charge capacities (between ca. 160 and 180 mAh g(-1)) corresponding to ca. 2/3 of theoretical capacity are reached albeit, in both cases, capacity retention and cyclability are not satisfactory enough to consider these materials as alternatives to LiCoO2. (C) 2013 Elsevier Inc. All rights reserved.

Salt and cocrystals of sildenafil with dicarboxylic acids: solubility and pharmacokinetic advantage of the glutarate salt

Sildenafil is a drug used to treat erectile dysfunction and pulmonary arterial hypertension. Because of poor aqueous solubility of the drug, the citrate salt, with improved solubility and pharmacokinetics, has been marketed. However, the citrate salt requires an hour to reach its peak plasma concentration. Thus, to improve solubility and bioavailability characteristics, cocrystals and salts of the drug have been prepared by treating aliphatic dicarboxylic acids with sildenafil; the N-methylated piperazine of the drug molecule interacts with the carboxyl group of the acid to form a heterosynthon. Salts are formed with oxalic and fumaric acid; salt monoanions are formed with succinic and glutaric acid. Sildenafil forms cocrystals with longer chain dicarboxylic acids such as adipic, pimelic, suberic, and sebacic acids. Auxiliary stabilization via C-H center dot center dot center dot O interactions is also present in these cocrystals and salts. Solubility experiments of sildenafil cocrystal/salts were carried out in 0.1N HCl aqueous medium and compared with the solubility of the citrate salt. The glutarate salt and pimelic acid cocrystal dissolve faster than the citrate salt in a two hour dissolution experiment. The glutarate salt exhibits improved solubility (3.2-fold) compared to the citrate salt in water. Solubilities of the binary salts follow an inverse correlation with their melting points, while the solubilities of the cocrystals follow solubilities of the coformer. Pharmacokinetic studies on rats showed that the glutarate salt exhibits doubled plasma AUC values in a single dose within an hour compared to the citrate salt. The high solubility of glutaric acid, in part originating from the strained conformation of the molecule and its high permeability, may be the reason for higher plasma levels of the drug.