A Latex Metabolite Benefits Plant Fitness under Root Herbivore Attack

Plants produce large amounts of secondary metabolites in their shoots and roots and store them in specialized secretory structures. Although secondary metabolites and their secretory structures are commonly assumed to have a defensive function, evidence that they benefit plant fitness under herbivore attack is scarce, especially below ground. Here, we tested whether latex secondary metabolites produced by the common dandelion (Taraxacum officinale agg.) decrease the performance of its major native insect root herbivore, the larvae of the common cockchafer (Melolontha melolontha), and benefit plant vegetative and reproductive fitness under M. melolontha attack. Across 17 T. officinale genotypes screened by gas and liquid chromatography, latex concentrations of the sesquiterpene lactone taraxinic acid ��-D-glucopyranosyl ester (TA-G) were negatively associated with M. melolontha larval growth. Adding purified TA-G to artificial diet at ecologically relevant concentrations reduced larval feeding. Silencing the germacrene A synthase ToGAS1, an enzyme that was identified to catalyze the first committed step of TA-G biosynthesis, resulted in a 90% reduction of TA-G levels and a pronounced increase in M. melolontha feeding. Transgenic, TA-G-deficient lines were preferred by M. melolontha and suffered three times more root biomass reduction than control lines. In a common garden experiment involving over 2,000 T. officinale individuals belonging to 17 different genotypes, high TA-G concentrations were associated with the maintenance of high vegetative and reproductive fitness under M. melolontha attack. Taken together, our study demonstrates that a latex secondary metabolite benefits plants under herbivore attack, a result that provides a mechanistic framework for root herbivore driven natural selection and evolution of plant defenses below ground.

Creating LaTeX documents from within Stata using texdoc

This paper discusses the use of -texdoc- for creating LaTeX documents from within Stata. Specifically, -texdoc- provides a way to embed LaTeX code directly in a do-file and to automate the integration of results from Stata in the final document. The command can be used, for example, to assemble automatic reports, write a Stata Journal article, prepare slides for classes, or put together solutions for homework assignments.

Creating LaTeX documents from within Stata

In this presentation, I present a new user package called texdoc. texdoc can be used to create a LaTeX document from within Stata in a weaving fashion. This is especially useful if you want to produce a LaTeX document that contains Stata output, such as a Stata Journal article or solutions to statistics homework assignments. I will provide examples illustrating the usage of texdoc.

Generador de ex��menes test aleatorios basados en R y LATEX

El presente documento aborda el proceso de realizaci��n del proyecto \Generaci��n aleatoria de Test" utilizando para ello un gestor de base de datos y principalmente los lenguajes LaTex y R. Tambi��n se realizar�� una explicaci��n de c��mo se han integrado entre s ambos lenguajes relacion��ndolos con la base de datos, c��mo se han codificado los m��todos empleados para la realizaci��n del sistema de test, los problemas que han ido surgiendo a lo largo de dicha integraci��n y desarrollo y las mejores medidas que se han adoptado para tratar de solventarlos. Por ��ltimo, se ilustraran unos ejemplos de instalaci��n y funcionamiento del programa y se comentaran unas breves conclusiones obtenidas tras su finalizaci��n y las posibles l��neas futuras que se pueden adoptar de cara a progresar y mejorar el programa.

Characterization of Euphorbia characias Latex Amine Oxidase1

A copper-containing amine oxidase from the latex of Euphorbia characias was purified to homogeneity and the copper-free enzyme obtained by a ligand-exchange procedure. The interactions of highly purified apo- and holoenzyme with several substrates, carbonyl reagents, and copper ligands were investigated by optical spectroscopy under both aerobic and anaerobic conditions. The extinction coefficients at 278 and 490 nm were determined as 3.78 �� 105 m���1 cm���1 and 6000 m���1 cm���1, respectively. Active-site titration of highly purified enzyme with substrates and carbonyl reagents showed the presence of one cofactor at each enzyme subunit. In anaerobiosis the native enzyme oxidized one equivalent substrate and released one equivalent aldehyde per enzyme subunit. The apoenzyme gave exactly the same 1:1:1 stoichiometry in anaerobiosis and in aerobiosis. These findings demonstrate unequivocally that copper-free amine oxidase can oxidize substrates with a single half-catalytic cycle. The DNA-derived protein sequence shows a characteristic hexapeptide present in most 6-hydroxydopa quinone-containing amine oxidases. This hexapeptide contains the tyrosinyl residue that can be modified into the cofactor 6-hydroxydopa quinone.

Programas de C��lculo Cient��fico y Procesamiento de Textos: LaTeX. Pr��ctica 1

Ejercicios LaTeX Sesi��n 1

Programas de C��lculo Cient��fico y Procesamiento de Textos: LaTeX. Pr��ctica 2

Ejercicios LaTeX Sesi��n 2

Programas de C��lculo Cient��fico y Procesamiento de Textos: LaTeX. Pr��ctica 3

Ejercicios LaTeX Sesi��n 3

TEXDOC: Stata module to create a LaTeX document including Stata output

texdoc provides tools to create a LaTeX document from within Stata in a weaving fashion. This is especially useful if you want to produce a LaTeX document that contains Stata output, such as, e.g., a Stata Journal article or solutions to statistics homework assignments.

Styrene-butadiene latex modifiers for bridge deck overlay concrete /

Mode of access: Internet.

Responsive core���shell latex particles as colloidosome microcapsule membranes

Responsive core-shell latex particles are used to prepare colloidosome microcapsules using thermal annealing and internal cross-linking of the shell, allowing production of the microcapsules at high concentrations. The core-shell particles are composed of a polystyrene core and a shell of poly[2-(dimethylamino)ethyl methacrylate]-b-poly[methyl methacrylate] (PDMA-b-PMMA) chains adsorbed onto the core surface, providing steric stabilisation. The PDMA component of adsorbed polymer shell confers the latex particle thermal and pH responsive characteristics, it also provides glass transitions at lower temperatures than that of the core and reactive amine groups. These features facilitate the formation of stable Pickering emulsion droplets and the immobilisation of the latex particle monolayer on these droplets to form colloidosome microcapsules. The immobilisation is achieved through thermal annealing or cross-linking of the shell at mild conditions feasible for large scale economic production. We demonstrate here that it is possible to anneal the particle monolayer on the emulsion drop surface at 75-86 ��C by using the lower glass transition temperature of the shell compared to that of the polystyrene cores (~108 ��C). The colloidosome microcapsules formed have a rigid membrane basically composed of a monolayer of particles. Chemical cross-linking has also been successfully achieved by confining a cross-linker within the disperse droplet. This approach leads to the formation of single-layered stimulus-responsive soft colloidosome membranes and provides the advantage of working at very high emulsion concentrations since inter-droplet cross-linking is thus avoided. The porosity and mechanical strength of microcapsules are also discussed here in terms of the observed structure of the latex particle monolayers forming the capsule membrane.

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