Tungsten(0)-carbonyl complexes of naphthylazoimidazoles

The reaction of W(CO)(6) with 1-alkyl-2-(naphthyl-alpha-azo)imidazole (alpha-NaiR) has synthesized [W(CO)(5)(alpha-NaiR-N)] (alpha-NaiR-N refers to the monodentate imidazole-N donor ligand) at room temperature. The structure of[W(CO)(5)(alpha-NaiMe-N)] shows a monodentate imidazole-N coordination of 1-methyl-2-(naphthyl-alpha-azo)imidazole (alpha-NaiMe). The complexes are characterized by elemental, mass and other spectroscopic data (IR, UV-Vis, NMR). On refluxing in THF at 323 K, [W(CO)(5)(alpha-NaiR-N)] undergoes decarbonylation to give [W(CO)(4)(alpha-NaiR-N,N')] (alpha-NaiR-N,N' refers to the imidazole-N(N), azo-N(N') bidentate chelator). Cyclic voltammetry shows metal oxidation (W-0/W-1) and ligand reductions (azo/azo(-), azo(-)/azo(=)). The redox and electronic properties are explained by theoretical calculations using an optimized geometry. DFT computation of [W(CO)(5)(alpha-NaiMe-N)] suggests that the major contribution to the HOMO/HOMO - 1 come from W cl-orbitals and the orbitals of CO. The LUMOs are occupied by alpha-NaiMe functions. The back bonding interaction thus originates from the W(CO)(n) moiety to the LUMO of alpha-NaiR. A TD-DFT calculation has ascribed that HOMO/HOMO - 1 -> LUMO is a mixture of metal-to-ligand and ligand-to-ligand charge transfer underlying the CO -> azoimine contribution. The complexes show emission spectra at room temperature. [W(CO)(4)(alpha-NaiR-N,N')] shows a higher fluorescence quantum yield (phi = 0.05-0.07) than [W(CO)(5)(alpha-NaiR-N)] (phi = 0.01-0.02). (C) 2008 Elsevier Ltd. All rights reserved.

Ultrafast Solvation Dynamics of an Ion in the gamma-Cyclodextrin Cavity: The Role of Restricted Environment

A detailed study of the solvation dynamics of a charged coumarin dye molecule in gamma-cyclodextrin/water has been carried out by using two different theoretical approaches. The first approach is based on a multishell continuum model (MSCM). This model predicts the time scales of the dynamics rather well, provided an accurate description of the frequency-dependent dielectric function is supplied. The reason for this rather surprising agreement is 2-fold. First, there is a cancellation of errors, second, the two-zone model mimics the heterogeneous microenvironment surrounding the ion rather well. The second approach is based on the molecular hydrodynamics theory (MI-IT). In this molecular approach, the solvation dynamics has been studied by restricting the translational motion of the solvent molecules enclosed within the cavity. The results from the molecular theory are also in good agreement with the experimental results. Our study indicates that, in the present case, the restricted environment affects only the long time decay of the solvation time correlation function. The short time dynamics is still governed by the librational (and/or vibrational) modes present in bulk water.

trans-Dichloro-bis-(arylazoimidazole)palladium(II): Synthesis, Structure, Photoisomerization, and DFT Calculation

Reaction between PdCl2 and 1-alkyl-2-(arylazo)imidazole (RaaiR') or 1-alkyl-2-(naphthyl-alpha/beta-azo)imidazole (alpha/beta-NaiR') under reflux in ethanol has isolated complexes of compositions Pd(RaaiR')(2)Cl-2 (5, 6) and Pd(alpha/beta-NaiR')(2)Cl-2 (7, 8). The X-ray structure determination of one of the molecules, Pd(alpha-NaiBz)(2)Cl-2 (7c), has reported a trans-PdCl2 configuration, and alpha-NaiBz acts as monodentate N(imidazole) donor ligand. The spectral (IR, UV-vis, H-1 NMR) data support the structure. UV light irradiation (light source: Perkin-Elmer LS 55 spectrofluorimeter, Xenon discharge lamp, lambda = 360-396 nm) in a MeCN solution of the complexes shows E-to-Z isomerization of the coordinated azoimidazole unit. The reverse transformation, Z-to-E, is very slow with visible light irradiation. Quantum yields (phi(E-Z)) of E-to-Z isomerization are calculated, and phi is lower than that of the free ligand but comparable with those of Cd(II) and Hg(II) complexes of the same ligand. The Z-to-E isomerization is a thermally induced process. The activation energy (E-a) of Z-to-E isomerization is calculated by controlled-temperature experimentation. cis-Pd(azoimidazole)Cl-2 complexes (azomidazole acts as N(imidazole) and N(azo) Chelating ligand) do not respond upon light irradiation, which supports the idea that the presence of noncoordinated azo-N to make free azo (-N=N-) function is important to reveal photochromic activity. DFT calculation of Pd(alpha-NaiBz)(2)Cl-2 (7c) has suggested that the HOMO of the molecule is constituted of Pd (32%) and Cl (66%), and hence photo excitation may use the energy of Pd and Cl instead of that of the photofunctional -N=N-Ar motif; thus, the rate of photoisomerization and quantum yield decrease versus the free ligand values.

Ginger (Zingiber officinale) autotetraploids with improved processing quality produced by an in vitro colchicine treatment

Ginger autotetraploids were produced by immersing shoot tips in a 0.5% w/v colchicine, 2% v/v dimethyl sulfoxide solution for 2 h. Stomatal measurements were used as an early indicator of ploidy differences in culture with mean stomata length of tetraploids (49.2 μm) being significantly larger than the diploid (38.8 µm). Of the 500 shoot tips treated, 2% were characterised as stable autotetraploid lines following field evaluation over several seasons. Results were confirmed with flow cytometry and, of the 7 lines evaluated for distinctness and uniformity, 6 were solid tetraploid mutants and 1 was a periclinal chimera. Significant differences were noted between individual tetraploid lines in terms of shoot length, leaf length, leaf width, size of rhizome sections (knob weight) and fibre content. The solid autotetraploid lines had significantly wider, greener leaves than the diploids, they had significantly fewer but thicker shoots and, although ‘Queensland’ (the diploid parent from which the tetraploids were derived) had a greater total rhizome mass at harvest, its knob size was significantly smaller. From the autotetraploid lines, one line was selected for commercial release as ‘Buderim Gold’. It compared the most favourably with ‘Queensland’ in terms of the aroma/flavour profile and fibre content at early harvest, and had consistently good rhizome yield. More importantly it produced large rhizome sections, resulting in a higher recovery of premium grade confectionery ginger and a more attractive fresh market product.

Field evaluation of micropropagated and conventionally propagated ginger in subtropical Queensland

The growth and performance of micropropagated ginger (Zingiber officinale Roscoe) was compared with 'seed'-derived plants in field trials conducted in south-eastern Queensland. In the first generation ex vitro, micropropagated plants had significantly (P<0.01) reduced rhizome yield with smaller knobs and more roots. Micropropagated plants had a greater (P<0.01) shoot: root (rhizome) ratio compared with seed-derived plants. Shoots from micropropagated plants were also significantly (P<0.01) smaller with a greater number of shoots per plant. The unusual shoot morphology of the micropropagated plants did not appear to be related to the presence of benzylaminopurine, a plant growth hormone added to the multiplication medium, as plants subcultured for 3 cycles on a hormone-free medium also exhibited similar characteristics. Seed collected from the micropropagated plants and seed-derived plants was harvested and, despite the micropropagated seed being significantly (P<0.01) smaller, by the second generation ex vitro there were no significant differences between the treatments. Factors that can improve rhizome size, while reducing production costs, need to be identified before micropropagated plants can be recommended for routine use in the ginger industry as a source of disease and pest-free planting material.

Peronospora lamii on Lamiaceae in Australia

A detailed description and illustration of the Australian specimens of Peronospora lamii on Salvia spp. and on Lamium amplexicaule (Lamiaceae) are given.

Interaction of Cibacron Blue F3G-A and Procion Red HE-3B with sheep liver 5,10-methylenetetrahydrofolate reductase

Cibacron Blue F3G-A, a probe used to monitor nucleotide binding domains in enzymes, inhibited sheep liver 5, 10-methylenetetrahydrofolate reductase competitively with respect to 5-methyltetrahydrofolate and NADPH. The Ki values obtained by kinetic methods and the Kd value for the binding of the dye to the enzyme estimated by protein fluorescence quenching were in the range 0·9-1·2 μM. Another triazine dye, Procion Red HE-3B interacted with the enzyme in an essentially similar manner to that observed with Cibacron Blue F3G-A. These results as well as the interaction of the dye with the enzyme monitored by difference spectroscopy and intrinsic protein fluorescence quenching methods indicated that the dye was probably interacting at the active site of the enzyme by binding at a hydrophobic region.

Differing mechanisms of simple nitrile formation on glucosinolate degradation in Lepidium sativum and Nasturtium officinale seeds.

Glucosinolates are sulphur-containing glycosides found in brassicaceous plants that can be hydrolysed enzymatically by plant myrosinase or non-enzymatically to form primarily isothiocyanates and/or simple nitriles. From a human health perspective, isothiocyanates are quite important because they are major inducers of carcinogen-detoxifying enzymes. Two of the most potent inducers are benzyl isothiocyanate (BITC) present in garden cress (Lepidium sativum), and phenylethyl isothiocyanate (PEITC) present in watercress (Nasturtium officinale). Previous studies on these salad crops have indicated that significant amounts of simple nitriles are produced at the expense of the isothiocyanates. These studies also suggested that nitrile formation may occur by different pathways: (1) under the control of specifier protein in garden cress and (2) by an unspecified, non-enzymatic path in watercress. In an effort to understand more about the mechanisms involved in simple nitrile formation in these species, we analysed their seeds for specifier protein and myrosinase activities, endogenous iron content and glucosinolate degradation products after addition of different iron species, specific chelators and various heat treatments. We confirmed that simple nitrile formation was predominantly under specifier protein control (thiocyanate-forming protein) in garden cress seeds. Limited thermal degradation of the major glucosinolate, glucotropaeolin (benzyl glucosinolate), occurred when seed material was heated to >120 degrees C. In the watercress seeds, however, we show for the first time that gluconasturtiin (phenylethyl glucosinolate) undergoes a non-enzymatic, iron-dependent degradation to a simple nitrile. On heating the seeds to 120 degrees C or greater, thermal degradation of this heat-labile glucosinolate increased simple nitrile levels many fold.

Development of pseudo-two-dimensional turbulent wakes

Pseudotwo-dimensional wakes are generated by introducing spanwise cellular structures into an otherwise plane turbulent wake by means of the castellated blunt trailing edges of different configurations. The transverse growths of these coflowing cellular wakes are found to be independent of each other without any noticeable spanwise interaction. This wake growth is examined in the light of the plane equilibrium wake analysis. Though these wakes are not found to be exactly self-similar, their growth shows a nonmonotonous approach toward the asymptotic state appropriate to that of a plane wake. The dye emission in the wakes illustrated a coherent vortical structure in the transverse plane, similar to that of the usual two-dimensional wake, in spite of the initial spanwise irregularities.

Anthraquinones from the Fungus Dermocybe sanguinea as Textile Dyes

This study is based on the multidiciplinary approach of using natural colorants as textile dyes. The author was interested in both the historical and traditional aspects of natural dyeing as well as the modern industrial applications of the pure natural compounds. In the study, the anthraquinone compounds were isolated as aglycones from the ectomycorrhizal fungus Dermocybe sanguinea. The endogenous beta-glucosidase of the fungus was used to catalyse the hydrolysis of the O-glycosyl linkage in emodin- and dermocybin-1-beta-D-glucopyranosides. The method, in which 10.45 kg of fresh fungi was starting material, yielded two fractions: 56.0 g of Fraction 1 (94% of the total amount of pigment,) consisting almost exclusively of the main pigments emodin and dermocybin, and 3.3 g of Fraction 2 (6%) consisting mainly of the anthraquinone carboxylic acids. The anthraquinone compounds in Fractions 1 and 2 were separated by one- and two-dimensional thin-layer-chromatography (TLC) using silica plates. 1D TLC showed that neither an acidic nor a basic solvent system alone separated completely all the anthraquinones isolated from D. sanguinea, in spite of the variation of the rations of the solvent components in the systems. Thus, a new 2D TLC technique was developed, applying n-pentanol-pyridine-methanol (6:4:3, v/v/v) and toluene-ethyl acetate-ethanol-formic acid (10:8:1:2, v/v/v/v) as eluents. Fifteen different anthraquinone derivatives were completely separated from one another. Emodin, physcion, endocrocin, dermolutein, dermorubin, 5-chlorodermorubin, emodin-1-beta-D-glucopyranoside, dermocybin-1-beta-D-glucopyranoside and dermocybin, and five new compounds, not earlier identified in D. sanguinea, 7-chloroemodin, 5,7-dichloroemodin, 5,7-dichloroendocrocin, 4-hydroxyaustrocorticone and austrocorticone, were separated and identified on the basis of their Rf-values, UV/Vis spectra and mass spectra. One substance remained unidentified, because of its very low concentration. The anthraquinones in Fractions 1 and 2 were preparatively separeted by liquid-liquid partition, with isopropylmethyl ketone and aqueous phosphate buffer as the solvent system. Advantage was taken of the principle of stepwise pH-gradient elution. The multiple liquid-liquid partition (MLLP) offered an excellent method for the preparative separation of compounds, which contain acidic groups such as the phenolic OH and COOH groups. Due to their strong aggregation properties, these compounds are, without derivatization, very difficult to separate on a preparative scale by chromatographic methods. By the MLLP method remarkable separations were achieved for the components in each mixture. Emodin and dermocybin were both obtained from Fraction 1 in a purity of at least 99%. Pure emodin and dermocybin were applied as mordant dyes to wool and polyamide and as disperse dyes to polyester and polyamide, using the high temperature (HT) technique. A mixture of dermorubin and 5-chlorodermorubin was applied as an acid dye to wool. In these experiments, synthetic dyes were used as references. Experiments were also performed using water extract of the air-dried fungi as dye liquor for wool and silk. The main colouring compounds in the crude water extract were emodin and dermocybin, which indicated that the O-glycosyl linkages in emodin- and dermocybin-1-beta-D-glucopyranosides were broken by the beta-glucosidase enzyme. Apparently, the hydrolysis occurred during the drying of the fungi and during the soaking of the dried fruit bodies overnight when preparing the dyebath. The colour of each dyed material was investigated in terms of the CIELAB L*, a* and b* values, and the colour fastness to light, washing and rubbing was tested according to the ISO standards. In the mordant dyeing experiments, emodin dyed wool and polyamide yellow and red, depending on the pH of the dyebath. Dermocybin gave purple and violet colours. The colour fastness of the mordant-dyed fabrics varied from good to moderate. The fastness properties of the natural anthraquinone carboxylic acids on wool were good, indicating the strength of the ionic bonds between the COO- groups of the dyes and the NH3+ groups of the fibres. In the disperse dyeing experiments, emodin dyed polyester bright yellow and dermocybin bright reddish-orange, and the fabrics showed excellent colour fastness. In contrast, emodin and dermocybin successfully dyed polyamide brownish-orange and wine-red, respectively, but with only moderate fastness. In industrial dyeing processes, natural anthraquinone aglycone mixtures dyed wool and silk well even at low concentrations of mordants, i.e. with 10% of the weight of the fibre (owf) of KAl(SO4)2 and 1 or 0.5% owf of other mordants. This study showed that purified natural anthraquinone compounds can produce bright hues with good colour-fastness properties in different textile materials. Natural anthraquinones have a significant potential for new dyeing techniques and will provide useful alternatives to synthetic dyes.

High-resolution melt-curve analysis of random-amplified-polymorphic-DNA markers, for the characterisation of pathogenic Leptospira.

A new test for pathogenic Leptospira isolates, based on RAPD-PCR and high-resolution melt (HRM) analysis (which measures the melting temperature of amplicons in real time, using a fluorescent DNA-binding dye), has recently been developed. A characteristic profile of the amplicons can be used to define serovars or detect genotypes. Ten serovars, of leptospires from the species Leptospira interrogans (serovars Australis, Robinsoni, Hardjo, Pomona, Zanoni, Copenhageni and Szwajizak), L. borgpetersenii (serovar Arborea), L. kirschneri (serovar Cynopteri) and L. weilii (serovar Celledoni), were typed against 13 previously published RAPD primers, using a real-time cycler (the Corbett Life Science RotorGene 6000) and the optimised reagents from a commercial kit (Quantace SensiMix). RAPD-HRM at specific temperatures generated defining amplicon melt profiles for each of the tested serovars. These profiles were evaluated as difference-curve graphs generated using the RotorGene software package, with a cut-off of at least 8 'U' (plus or minus). The results demonstrated that RAPD-HRM can be used to measure serovar diversity and establish identity, with a high degree of stability. The characterisation of Leptospira serotypes using a DNA-based methodology is now possible. As an objective and relatively inexpensive and rapid method of serovar identification, at least for cultured isolates, RAPD-HRM assays show convincing potentia.

Pre-cropping with canola decreased Pratylenchus thornei populations, arbuscular mycorrhizal fungi, and yield of wheat.

Root-lesion nematode (Pratylenchus thornei) significantly reduces wheat yields in the northern Australian grain region. Canola is thought to have a 'biofumigation' potential to control nematodes; therefore, a field experiment was designed to compare canola with other winter crops or clean-fallow for reducing P. thornei population densities and improving growth of P. thornei-intolerant wheat (cv. Batavia) in the following year. Immediately after harvest of the first-year crops, populations of P. thornei were lowest following various canola cultivars or clean-fallow (1957-5200 P. thornei/kg dry soil) and were highest following susceptible wheat cultivars (31 033-41 294/kg dry soil). Unexpectedly, at planting of the second-year wheat crop, nematode populations were at more uniform lower levels (<5000/kg dry soil), irrespective of the previous season's treatment, and remained that way during the growing season, which was quite dry. Growth and grain yield of the second-year wheat crop were poorest on plots previously planted with canola or left fallow due to poor colonisation with arbuscular mycorrhizal (AM) fungi, with the exception of canola cv. Karoo, which had high AM fungal colonisation and low wheat yields. There were significant regressions between growth and yield parameters of the second-year wheat and levels of AMF following the pre-crop treatments. Thus, canola appears to be a good crop for reducing P. thornei populations, but AM fungal-dependence of subsequent crops should be considered, particularly in the northern Australian grain region.

Inhibition of H2O2 generation in rat liver mitochondria by radical quenchers and phenolic compounds

Generation of H2O2 by rat liver mitochondria with choline, glycerol 1-phosphate and proline as substrates has been shown by using high-concentration phosphate buffer. Rates obtained under these conditions were higher and more consistent as compared with the earlier reports with high-concentration mannitol/sucrose/Tris buffer. Sulphate ions could replace phosphate indicating a requirement for a high concentration of oxygen-containing anions. H2O2 generation was dependent on the presence of native mitochondria and substrate. Maximal rates with various substrates were found to be the same as with succinate. Values of Km and Vmax for H2O2 generation were considerably less than those obtained for respective dehydrogenase activities, measured by dye reduction. Scavengers of O2-. and OH. inhibited generation of H2O2. ATP, ADP, thyronine derivatives and a number of phenolic compounds also showed very potent inhibitory effects of H2O2 generation, whereas phenyl compound had no effect. Phenolic compounds did not have any effect on mitochondrial superoxide dismutase and choline dehydrogenase activities as well as on O2-. generation by the xanthine-xanthine oxidase system. Inhibition by phenolic compounds may have potential for regulation of the intracellular concentration of H2O2, that is not considered to have a "second messenger' function.

ACIAR Productivity and profitability enhancing tropical pulses in Indonesia and Australia

The project aims at improving the productivity and profitability of mung beans, soy beans and peanuts.

Preparation and properties of nickel(II) complex dyes

The preparation and properties of five new dyes derived from nickel(I1) ions and aromatic azo derivatives of ethylenebls(P-ketoesters) are reported.