Auxin - oxylipin crosstalk in stress responses of plant roots

Phytohormones regulate a wide array of developmental processes throughout the life cycle of plants. Over recent years, mounting evidence led to the widely accepted concept that plant hormone action is not the read-out of linear pathways, but determined by the extensive combinatorial activity of the signaling molecules and the integration of their signaling pathways, both in terms of regulating growth and development and in adapting to external stimuli. Recent work is beginning to shed light on the crosstalk of both nominally synergistically and antagonistically acting plant hormones such as, for example, auxins with oxylipins. Here, we report that oxylipins directly contribute to the regulation of the expression of two Arabidopsis YUCCA (YUC) genes, YUC8 and YUC9. Similar to previously characterized YUC family members, we identify both YUC8 and YUC9 as involved in local auxin biosynthesis, as demonstrated by the altered auxin contents and auxin-dependent phenotypes displayed by loss-of function mutants and transgenic overexpressing lines. Gene expression data obtained by qPCR analysis and microscopic examination of promoter-reporter lines reveal an oxylipin-mediated regulation of YUC9 expression that is dependent on the COI1 signal transduction pathway. The microscopic data indicate a functional overlap of the two analyzed auxin biosynthesis genes, but also point out specific functions for YUC8 and YUC9, which are in part related to different spatio-temporal expression pattern. In support of these findings, the analyzed yuc knockout mutants had lower free auxin contents and displayed a reduced response to oxylipins. This work provides evidence of a molecular mechanism that links oxylipin signaling with auxin homeostasis.

Rational invariants on the space of all structures of algebras on a two-dimensional vector space

Rational invariants on the space of all structures of algebras on a two-dimensional vector space

Bioavailability and extraction of heavy metals from contaminated soil by Atriplex halimus

Pot experiments were performed to evaluate the phytoremediation capacity of plants of Atriplex halimus grown in contaminated mine soils and to investigate the effects of organic amendments on the metal bioavailability and uptake of these metals by plants. Soil samples collected from abandoned mine sites north of Madrid (Spain) were mixed with 0, 30 and 60 Mg ha?1 of two organic amendments, with different pH and nutrients content: pine-bark compost and horse- and sheep-manure compost. The increasing soil organic matter content and pH by the application of manure amendment reduced metal bioavailability in soil stabilising them. The proportion of Cu in the most bioavailable fractions (sum of the water-soluble, exchangeable, acid-soluble and Fe?Mn oxides fractions) decreased with the addition of 60 Mg ha?1 of manure from 62% to 52% in one of the soils studied and from 50% to 30% in the other. This amendment also reduced Zn proportion in water-soluble and exchangeable fractions from 17% to 13% in one of the soils. Manure decreased metal concentrations in shoots of A. halimus, from 97 to 35 mg kg?1 of Cu, from 211 to 98 mg kg?1 of Zn and from 1.4 to 0.6 mg kg?1 of Cd. In these treatments there was a higher plant growth due to the lower metal toxicity and the improvement of nutrients content in soil. This higher growth resulted in a higher total metal accumulation in plant biomass and therefore in a greater amount of metals removed from soil, so manure could be useful for phytoextraction purposes. This amendment increased metal accumulation in shoots from 37 to 138 mg pot?1 of Cu, from 299 to 445 mg pot?1 of Zn and from 1.8 to 3.7 mg pot?1 of Cd. Pine bark amendment did not significantly alter metal availability and its uptake by plants. Plants of A. halimus managed to reduce total Zn concentration in one of the soils from 146 to 130 mg kg?1, but its phytoextraction capacity was insufficient to remediate contaminated soils in the short-to-medium term. However, A. halimus could be, in combination with manure amendment, appropriate for the phytostabilization of metals in mine soils.

Extraction of subjective properties in image processing

Most of the present digital images processing methods are related with objective characterization of external properties as shape, form or colour. This information concerns objective characteristics of different bodies and is applied to extract details to perform several different tasks. But in some occasions, some other type of information is needed. This is the case when the image processing system is going to be applied to some operation related with living bodies. In this case, some other type of object information may be useful. As a matter of fact, it may give additional knowledge about its subjective properties. Some of these properties are object symmetry, parallelism between lines and the feeling of size. These types of properties concerns more to internal sensations of living beings when they are related with their environment than to the objective information obtained by artificial systems. This paper presents an elemental system able to detect some of the above-mentioned parameters. A first mathematical model to analyze these situations is reported. This theoretical model will give the possibility to implement a simple working system. The basis of this system is the use of optical logic cells, previously employed in optical computing.

Fruit by fruit identification of mealy peaches. Extraction of storage features.

Mealiness is a negative attribute of sensory texture, characterised by the lack of juiciness decrease in the total amount of of water content of tissues. Peach mealy textures are known as \ and leatheriness. Besides the lack of juiciness and flavour, that characterises mealy fruits, in associated with internal browning near the stone and an incapacity of ripening although there i ripe appearance. It is considered as a physiological disorder that appears in stone fruits probably < unbalanced pectolitic enzyme activity during storage. Since January 1996, a wide EC Project entitled: "Mealiness in fruits. Consumer perception and i detection" is being carried out. Within it, the Physical Properties Laboratory (ETSIA-UPM) working to develop instrumental procedures to detect mealiness in different types of fruits (s contributions by Barreiro to AgEng). The results obtained have shown to correlate well with \ measurements in apples (Barreiro et al), also we have succeeded in identifying individual mealy j the basis of instrumental measurement in peaches. The definition of these texture categories will be used in further studies as a base for new individual classification.

Some examples of the simultaneous use of closed-form and numerical solutions in shell structural analysis

The computational advantages of the use of different approaches -numerical and analytical ones- to the analysis of different parts of the same shell structure are discussed. Examples of large size problems that can be reduced to those more suitable to be handled by a personal related axisyrometric finite elements, local unaxisymmetric shells, geometric quasi-regular shells, infinite elements and homogenization techniques are described

Simultaneous determination of multiclass emerging contaminants in aquatic plants by ultrasound assisted matrix solid phase dispersion and GC-MS

A multiresidue method was developed for the simultaneous determination of 31 emerging contaminants (pharmaceutical compounds, hormones, personal care products, biocides and flame retardants) in aquatic plants. Analytes were extracted by ultrasound assisted-matrix solid phase dispersion (UA-MSPD) and determined by gas chromatography-mass spectrometry after sylilation. The method was validated for different aquatic plants (Typha angustifolia, Arundo donax and Lemna minor) and a semiaquatic cultivated plant (Oryza sativa) with good recoveries at concentrations of 100 and 25 ng g-1 wet weight, ranging from 70 to 120 %, and low method detection limits (0.3 to 2.2 ng g-1 wet weight). A significant difference of the chromatographic response was observed for some compounds in neat solvent versus matrix extracts and therefore quantification was carried out using matrix-matched standards in order to overcome this matrix effect. Aquatic plants taken from rivers located at three Spanish regions were analyzed and the compounds detected were parabens, bisphenol A, benzophenone-3, cyfluthrin and cypermethrin. The levels found ranged from 6 to 25 ng g-1 wet weight except for cypermethrin that was detected at 235 ng g-1 wet weight in Oryza sativa samples.

Phycologia australica; or, A history of Australian sea weeds ... and a synopsis of all known Australian Algae ... By William Henry Harvey.

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Natural history of Victoria. Prodromus of the zoology of Victoria; or, Figures and descriptions of the living species of all classes of the Victorian indigenous animals... By Frederick McCoy...

Decade 11-15

The C-terminal SET domains of ALL-1 and TRITHORAX interact with the INI1 and SNR1 proteins, components of the SWI/SNF complex

The ALL-1 gene was discovered by virtue of its involvement in human acute leukemia. Its Drosophila homolog trithorax (trx) is a member of the trx-Polycomb gene family, which maintains correct spatial expression of the Antennapedia and bithorax complexes during embryogenesis. The C-terminal SET domain of ALL-1 and TRITHORAX (TRX) is a 150-aa motif, highly conserved during evolution. We performed yeast two hybrid screening of Drosophila cDNA library and detected interaction between a TRX polypeptide spanning SET and the SNR1 protein. SNR1 is a product of snr1, which is classified as a trx group gene. We found parallel interaction in yeast between the SET domain of ALL-1 and the human homolog of SNR1, INI1 (hSNF5). These results were confirmed by in vitro binding studies and by demonstrating coimmunoprecipitation of the proteins from cultured cells and/or transgenic flies. Epitope-tagged SNR1 was detected at discrete sites on larval salivary gland polytene chromosomes, and these sites colocalized with around one-half of TRX binding sites. Because SNR1 and INI1 are constituents of the SWI/SNF complex, which acts to remodel chromatin and consequently to activate transcription, the interactions we observed suggest a mechanism by which the SWI/SNF complex is recruited to ALL-1/trx targets through physical interactions between the C-terminal domains of ALL-1 and TRX and INI1/SNR1.

Simultaneous determination of helical unwinding angles and intrinsic association constants in ligand–DNA complexes: The interaction between DNA and calichearubicin B

We present a helical unwinding assay for reversibly binding DNA ligands that uses closed circular DNA, topoisomerase I (Topo I), and two-dimensional agarose gel electrophoresis. Serially diluted Topo I relaxation reactions at constant DNA/ligand ratio are performed, and the resulting apparent unwinding of the closed circular DNA is used to calculate both ligand unwinding angle (φ) and intrinsic association constant (Ka). Mathematical treatment of apparent unwinding is formally analogous to that of apparent extinction coefficient data for optical binding titrations. Extrapolation to infinite DNA concentration yields the true unwinding angle of a given ligand and its association constant under Topo I relaxation conditions. Thus this assay delivers simultaneous structural and thermodynamic information describing the ligand–DNA complex. The utility of this assay has been demonstrated by using calichearubicin B (CRB), a synthetic hybrid molecule containing the anthraquinone chromophore of (DA) and the carbohydrate domain of calicheamicin γ1I. The unwinding angle for CRB calculated by this method is −5.3 ± 0.5°. Its Ka value is 0.20 × 106 M−1. For comparison, the unwinding angles of ethidium bromide and DA have been independently calculated, and the results are in agreement with canonical values for these compounds. Although a stronger binder to selected sites, CRB is a less potent unwinder than its parent compound DA. The assay requires only small amounts of ligand and offers an attractive option for analysis of DNA binding by synthetic and natural compounds.

Libya’s new unity government faces the mother of all rebuilding jobs

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The α chain of laminin-1 is independently secreted and drives secretion of its β- and γ-chain partners

A mammalian recombinant strategy was established to dissect rules of basement membrane laminin assembly and secretion. The α-, β-, and γ-chain subunits of laminin-1 were expressed in all combinations, transiently and/or stably, in a near-null background. In the absence of its normal partners, the α chain was secreted as intact protein and protein that had been cleaved in the coiled-coil domain. In contrast, the β and γ chains, expressed separately or together, remained intracellular with formation of ββ or βγ, but not γγ, disulfide-linked dimers. Secretion of the β and γ chains required simultaneous expression of all three chains and their assembly into αβγ heterotrimers. Epitope-tagged recombinant α subunit and recombinant laminin were affinity-purified from the conditioned medium of αγ and αβγ clones. Rotary-shadow electron microscopy revealed that the free α subunit is a linear structure containing N-terminal and included globules with a foreshortened long arm, while the trimeric species has the typical four-arm morphology of native laminin. We conclude that the α chain can be delivered to the extracellular environment as a single subunit, whereas the β and γ chains cannot, and that the α chain drives the secretion of the trimeric molecule. Such an α-chain-dependent mechanism could allow for the regulation of laminin export into a nascent basement membrane, and might serve an important role in controlling basement membrane formation.