Composição das sementes e dos óleos de semente de tabacos brasileiros

Tobacco seeds of Nicotiana tabacum L. and Nicotiana rustica L. Species were studied regarding protein and oil contents. Fatty acid composition of tobacco seed oils was determined, through as chromatography. The percentage of linoleic acid, the main fatty component, was found to lie between 65.0 and 74.3. It is reported, for the first time, the occurrence of erucic acid, in a percentage higher than trace, but only for two samples. Only with respect to the colour it was observed a difference between oils from the two species.Sementes de tabaco das espécies Nicotiana tabacum L. e Nicotiana rustica L. foram estudadas, comprovando-se seu alto teor oleaginoso. A composição dos óleos de tabaco em ácidos graxos foi examinada por cromatografia de gás, encontrando-se teores de 65,0 a 74,3% para o ácido linoléico, principal componente graxo. Relata-se, pela primeira vez, a ocorrência do ácido erúcico em quantidade maior que traços, embora apenas para duas amostras. Somente quanto à cor foi notada a diferença sensível entre os óleos das duas espécies estudadas

High resolution mapping of a novel late blight resistance gene Rpi-avll, from the wild Bolivian species Solanum avilesii

Both Mexico and South America are rich in Solanum species that might be valuable sources of resistance (R) genes to late blight (Phytophthora infestans). Here, we focus on an R gene present in the diploid Bolivian species S. avilesii. The genotype carrying the R gene was resistant to eight out of 10 Phytophthora isolates of various provenances. The identification of a resistant phenotype and the generation of a segregating population allowed the mapping of a single dominant R gene, Rpi-avl1, which is located in an R gene cluster on chromosome 11. This R gene cluster is considered as an R gene “hot spot”, containing R genes to at least five different pathogens. High resolution mapping of the Rpi-avl1 gene revealed a marker co-segregating in 3890 F1 individuals, which may be used for marker assisted selection in breeding programs and for further cloning of Rpi-avl

Plant-Expressed Cocaine Hydrolase Variants of Butyrylcholinesterase Exhibit Altered Allosteric Effects of Cholinesterase Activity and Increased Inhibitor Sensitivity

Butyrylcholinesterase (BChE) is an enzyme with broad substrate and ligand specificities and may function as a generalized bioscavenger by binding and/or hydrolyzing various xenobiotic agents and toxicants, many of which target the central and peripheral nervous systems. Variants of BChE were rationally designed to increase the enzyme’s ability to hydrolyze the psychoactive enantiomer of cocaine. These variants were cloned, and then expressed using the magnICON transient expression system in plants and their enzymatic properties were investigated. In particular, we explored the effects that these site-directed mutations have over the enzyme kinetics with various substrates of BChE. We further compared the affinity of various anticholinesterases including organophosphorous nerve agents and pesticides toward these BChE variants relative to the wild type enzyme. In addition to serving as a therapy for cocaine addiction-related diseases, enhanced bioscavenging against other harmful agents could add to the practicality and versatility of the plant-derived recombinant enzyme as a multivalent therapeutic

Natural history of Arabidopsis thaliana and oomycete symbioses

Molecular ecology of plant–microbe interactions has immediate significance for filling a gap in knowledge between the laboratory discipline of molecular biology and the largely theoretical discipline of evolutionary ecology. Somewhere in between lies conservation biology, aimed at protection of habitats and the diversity of species housed within them. A seemingly insignificant wildflower called Arabidopsis thaliana has an important contribution to make in this endeavour. It has already transformed botanical research with deepening understanding of molecular processes within the species and across the Plant Kingdom; and has begun to revolutionize plant breeding by providing an invaluable catalogue of gene sequences that can be used to design the most precise molecular markers attainable for marker-assisted selection of valued traits. This review describes how A. thaliana and two of its natural biotrophic parasites could be seminal as a model for exploring the biogeography and molecular ecology of plant–microbe interactions, and specifically, for testing hypotheses proposed from the geographic mosaic theory of co-evolution

Magnetic phase composition of strontium titanate implanted with iron ions

Thin magnetic films were synthesized by means of implantation of iron ions into single-crystalline (1 0 0) substrates of strontium titanate. Depth-selective conversion electron Mössbauer spectroscopy (DCEMS) indicates that origin of the samples magnetism is α-Fe nanoparticles. Iron-substituted strontium titanate was also identified but with paramagnetic behaviour at room temperature. Surface magneto-optical Kerr effect (SMOKE) confirms that the films reveal superparamagnetism (the low-fluence sample) or ferromagnetism (the high-fluence sample), and demonstrate absence of magnetic in-plane anisotropy. These findings highlight iron implanted strontium titanate as a promising candidate for composite multiferroic material and also for gas sensing applications. © 2011 Elsevier Ltd. All rights reserved

Structural and magnetic studies of Co and Fe implanted BaTiO 3 crystals

Singly-charged Co or Fe ions with energy 40 keV were implanted into single-domain ferroelectric plates of barium titanate (BaTiO 3) with high fluences in the range of (0.5-1.5) × 10 17 ion/cm 2 to create new magnetoelectric materials. Scanning electron microscopy (SEM) and conversion electron Mössbauer spectroscopy (CEMS) studies have shown that high-fluence implantation with 3d-ions results in formation of cobalt or iron nanoparticles in the near-surface irradiated region of perovskite-type crystal. With increasing the fluence, the both Co- and Fe-implanted BaTiO 3 samples reveal at first superparamagnetic, and then ferromagnetic properties at room temperature. Analysis of magnetic hysteresis loops measured in the in-plane and out-of-plane geometries have shown that ferromagnetic BaTiO 3:Co(Fe) nanocomposite layers display the "easy plane" magnetic anisotropy similar to that found for thin granular magnetic films. Together with our previous observation of the magnetoelectric effect in these samples, our structural and magnetic investigations show that the ion implantation is suitable to synthesize the desired magnetoelectric nanocomposite materials. © 2011 Elsevier B.V. All rights reserved

A microRNA profile of human CD8(+) regulatory T cells and characterization of the effects of microRNAs on Treg cell-associated genes.

Recently, regulatory T (Treg) cells have gained interest in the fields of immunopathology, transplantation and oncoimmunology. Here, we investigated the microRNA expression profile of human natural CD8(+)CD25(+) Treg cells and the impact of microRNAs on molecules associated with immune regulation. We purified human natural CD8(+) Treg cells and assessed the expression of FOXP3 and CTLA-4 by flow cytometry. We have also tested the ex vivo suppressive capacity of these cells in mixed leukocyte reactions. Using TaqMan low-density arrays and microRNA qPCR for validation, we could identify a microRNA 'signature' for CD8(+)CD25(+)FOXP3(+)CTLA-4(+) natural Treg cells. We used the 'TargetScan' and 'miRBase' bioinformatics programs to identify potential target sites for these microRNAs in the 3'-UTR of important Treg cell-associated genes. The human CD8(+)CD25(+) natural Treg cell microRNA signature includes 10 differentially expressed microRNAs. We demonstrated an impact of this signature on Treg cell biology by showing specific regulation of FOXP3, CTLA-4 and GARP gene expression by microRNA using site-directed mutagenesis and a dual-luciferase reporter assay. Furthermore, we used microRNA transduction experiments to demonstrate that these microRNAs impacted their target genes in human primary Treg cells ex vivo. We are examining the biological relevance of this 'signature' by studying its impact on other important Treg cell-associated genes. These efforts could result in a better understanding of the regulation of Treg cell function and might reveal new targets for immunotherapy in immune disorders and cancer

Ion beam synthesis and investigation of nanocomposite multiferroics based on barium titanate with 3d metal nanoparticles

Samples of nanocomposite multiferroics have been synthesized by implantation of Co+, Fe+, and Ni+ ions with an energy of 40 keV into ferroelectric barium titanate plates to doses in the range (0.5-1.5) × 1017 ions/cm2. It has been found that nanoparticles of metallic iron, cobalt, or nickel are formed in the barium titanate layer subjected to ion bombardment. With an increase in the implantation dose, the implanted samples sequentially exhibit superparamagnetic, soft magnetic, and, finally, strong ferromagnetic properties at room temperature. The average sizes of ion-synthesized 3d-metal nanoparticles vary in the range from 5 to 10 nm depending on the implantation dose. Investigation of the orientation dependence of the magnetic hysteresis loops has demonstrated that the samples show a uniaxial ("easy plane") magnetic anisotropy typical of thin granular magnetic films. Ferromagnetic BaTiO3: 3d metal samples are characterized by a significant shift of the ferromagnetic resonance signal in an external electric field, as well as by a large (in magnitude) magnetodielectric effect at room temperature. These results indicate that there is a strong magnetoelectric coupling between the ferroelectric barium titanate matrix and ion-synthesized nanoparticles of magnetic metals. © 2013 Pleiades Publishing, Ltd

Simultaneous determination of Deoxynivalenol, Deoxynivalenol-3-Glucoside and Nivalenol in wheat grains by HPLC-PDA with immunoaffinity column cleanup

Deoxynivalenol-3-glucoside (D3G) is a modified mycotoxin formed by the metabolism of plants through the conjugation of deoxynivalenol (DON) with glucose. Toxicology studies of D3G for human and animal health are still under investigation, and the development of practical and reliable methods for its direct determination, especially in cereal matrices, is of great importance. In the present study, a methodology for simultaneous determination of D3G, DON, and nivalenol (NIV) in wheat grains, using immunoaffinity column (IAC) cleanup, separation by C18 column and detection by ultraviolet (UV) absorption, was optimized and in-house validated. The results demonstrated adequate values of D3G recovery from IAC and spiked samples. Intraday precision, linearity, limit of detection and limit of quantification (LOQ) were also adequate for the determination of these mycotoxins. Range of applicability varied from 47.1 to 1000 g/kg for D3G and from 31.3 to 1000 g/kg for DON and NIV, with recovery ranging from 84.7±7.2 % to 112.3±8.1Felipe Trombete is grateful for a doctoral fellowship provided by the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES)