Genetic control of purothionins in wheat: problems of the aneuploid analysis when searching for regulatory genes

The study of the genetic control of purothionins in wheat endosperm illustrates some of the problems and pitfalls faced in aneuploid analysis of regulatory effects. Biochemical and genetic evidence is presented indicating that the possible regulatory effect of genes located in group 5 chromosomes on the expression of the purothionin structural genes located in group 1 chromosomes is not actually operating "in vivo"

Proyecto granja peletera de "Crocodylus" en el término municipal de Mucientes (Valladolid)

Se pretende establecer una explotación para cría de cocodrilo del Nilo y cocodrilo de las marismas en cautividad y de manera intensiva con el fin de aprovechar al máximo sus subproductos. De manera principal se extraerá la piel y se curtirá dentro de la propia explotación para su venta en el mercado peletero europeo, y de manera secundaria se aprovechara la carne y la grasa. El desafío más importante del proyecto es la cría de este tipo de animal en un clima frio, y la utilización para su termorregulación de una energía de futuro y totalmente natural como es la geotérmica.Máster en Ingeniería Agronómic

Lipid binding proteins from the endosperms of wheat and Oats

A protein, designated lipid binding protein (LBP), has been purified from the petrol extracts of wheat and oat endosperms by hydrochloric acid precipitation in a non-polar medium and preparative electrophoresis. The purified LBP appeared to be homogeneous both by electrophoresis in sodium dodecyl sulphate-polyacrylamide (SDS-PAGE) gels (MW ca 14 500) and by electrophoresis (PAGE) at pH 3.2. The amino acid composition indicates a high degree of homology between the LBPs from the two sources, as judged by the indexes of Cornish-Bowden and of Harris and Teller. As in the case of thionin, a previously characterized polypeptide from the ether extract, LBP becomes ether-insoluble, chloroform-soluble by precipitation with acetone, and solubility in ether is restored by binding of digalactosyl diglyceride to the chloroform-soluble form

Thionins: plant peptides that modify membrane permeability in cultured mammalian cells

Thionins, which are high-sulphur polypeptides present in the endosperm of wheat and related species, have been found to prevent growth and to inhibit macromolecular synthesis in cultured mammalian cells. Baby hamster kidney (BHK) cells were markedly more sensitive to thionins than the other cell lines tested (monkey CV1, mouse L, human HeLa). A thionin concentration of 5 μ/ml (1 μM) completely blocked translation in BHK cells. It was later found that omission of both calcium and magnesium ions from the medium strongly enhanced the inhibitory effects of thionins (BHK cells, 80% inhibition, 0.5 μ/ml). Several lines of evidence indicate that thionins might act at the membrane level. Indeed, both the 86Rb+ content and the nucleotide pool of BHK cells were drastically decreased at thionin concentrations that inhibited translation. In addition, thionin concentrations that did not affect macromolecular synthesis in these cells, allowed inhibition of translation by antibiotics, such as hygromycin Bthat are not able to cross the cell plasma membrane by themselves. Our results suggest that the inhibition of protein, RNA and DNA synthesis in BHK cells might be a consequence of membrane leakiness induced by thionin treatment. In this respect, particularly striking was the parallelism found between 86Rb+ leakage and inhibition of protein synthesis by treatment with different genetic variants of thionins (α1 purothionin, α2 purothionin, β purothionin from wheat; hordothionin from barley), as well as with the viscotoxins, which are homologous polypeptides from the European mistletoe

Cloning and nucleotide sequence of a cDNA encoding the precursor of the barley toxin a-hordothionin

A cDNA library, prepared from developing barley endosperm, was screened for thionin recombinants. Clone pTH1 was that with the largest insert out of three identified. The longest reading frame in the 610-base-pair insert codes for a protein of 127 amino acids that includes an internal sequence of 45 amino acids, which is identical to that obtained for the α-hordothionin by direct protein sequencing. The deduced thionin sequence is preceded by a leader sequence of 18 residues and followed by a sequence that corresponds to an acidic protein of 64 amino acids. This structure supports previous evidence indicating that thionin is synthesized as a much larger precursor, which undergoes two processing steps: the cotranslational cleavage of a leader sequence and the post-translational one of a larger peptide. The size of the mRNA was estimated to be about 950 bases by Northern analysis. Thionin concentration in mature endosperm of barley cv. Bomi was about twice that of its high-lysine mutant Risç 1508. The same difference was observed in thionin mRNA in the corresponding developing endosperms, indicating that gene expression is partially blocked in the mutant at a pretranslational leve

Synthesis and processing of thionin precursors in developing endosperm from barley (Hordeum vulgare)

Thionin is a lysine-rich polypeptide (mol. wt. 5000) which is synthesized in developing barley endosperm from - 8 days to - 30 days after anthesis. Two thionin precursors (THPl and THP2) have been identified using monospecific antibodies (A-TH) prepared against the mature protein. THPl, which is the only polypeptide recognized in vitro by A-TH, is encoded by a 7.5S mRNA obtained from membrane-bound polysomes, and its alkylated derivative has an apparent mol. wt. of 17 800. THP2, which is selected together with mature thionin by A-TH among labelled proteins in vivo, differs from THPl in apparent mol. wt. (17 400 alkylated) and in electrophoretic mobility at pH 3.2. Both THPl and THP2 are competed out of the antigen-antibody complex by purified thionin. The conversión of THP2 into thionin, which has been demonstrated in a pulse-chase experiment in vivo, is a post-translational process. As it has not been possible to detect THPl in vivo it is assumed that it is converted cotranslationally into THP2. Final deposition of thionin as an extrínsic membrane protein, possibly associated with the endoplasmic reticulum, has been tentatively established on the basis of subcellular fractionation experíments

Inhibition of eukaryotic cell-free protein synthesis by thionins from wheat endosperm

Thionins are polypeptide toxins of about 5000 molecular weight, present in the endosperms of many Gramineae, which modify membrane permeability and inhibit macromolecular synthesis in cultured mammalian cells. Evidence is presented that they inhibit in vitro protein synthesis at micromolar concentrations in cell-free systems derived from wheat germ or from rabbit reticulocytes. Inhibition seems to occur by direct binding of mRNA by the toxin, as judged by the ability of thionins to mediate retention of RNA in nitrocellulose filters and by the dependence of inhibitory concentrations on the amount of exogenous RNA added to the wheat-germ translation system. Commercial preparations of wheat-germ have been found to include some endosperm contamination (up to 15%), which may result in at least partially inhibitory concentrations of the toxin in the cell-free extracts

The CM-proteins from cereal endosperm: Immunochemical relationships

The CM-proteins, which are salt-soluble proteins that can be extracted with chloroform: methanol (2: 1, v/v), seem to be present in the endosperm of all the cereal species investigated. Antibodies raised against a mixture of the barley CM-proteins (A-H) cross-reacted with wheat and rye proteins in Ouchterlony tests and a detailed study was carried out for purified wheat (CM1, CM2. CM3. CM3') and barley (CMa, CMb, CMc, CMd) CM-proteins. [35Sl-Cysteine-labelled endosperm proteins from wheat and barley were investigated by immuno-precipitation, electrophoresis and fluorography using the antibodies (A-H) and also those to a mixture of wheat CM-proteins and to CMd. There was complete antigenic identity for all the wheat proteins and CMd, some of the other proteins showed partial antigenic identity. Previously proposed genetic and biochemical relationships among these proteins were confirmed in the present study

A hierarchy of ramified theories below primitive recursive arithmetic

The arithmetical theory EA(I;O) developed by Çagman, Ostrin and Wainer ([18] and [48]) provides a formal setting for the variable separation of Bellantoni-Cook predicative recursion [6]. As such, EA(I;O) separates variables into outputs, which are quantified over, and inputs, for which induction applies. Inputs remain free throughout giving inductions in EA(I;O) a pointwise character termed predicative induction. The result of this restriction is that the provably recursive functions are the elementary functions. An infinitary analysis brings out a connection to the Slow-Growing Hierarchy yielding є0 as the appropriate proof-theoretic ordinal in a pointwise sense. Chapters 1 and 2 are devoted to an exposition of these results. In Chapter 3 a new principle of 1-closure is introduced in constructing a conservative extension of EA(I;O) named EA1. This principle collapses the variable separation in EA(I;O) and allows quantification over inputs by acting as an internalised ω-rule. EA1 then provides a natural setting to address the problem of input substitution in ramified theories. Chapters 4 and 5 introduce a hierarchy of theories based upon alternate additions of the predicative induction and ∑1-closure principles. For 0 < k є N, the provably recursive functions of the theories EAk are shown to be the Grzegorczyk classes Ek+2. Upper bounds are obtained via embeddings into appropriately layered infinitary systems with carefully controlled bounding functions for existential quantifiers. The theory EA-ω, defined by closure under finite applications of these two principles, is shown to be equivalent to primitive recursive arithmetic. The hierarchy generated may be considered as an implicit ramification of the sub-system of Peano Arithmetic which restricts induction to ∑1-formulae.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Efectos de la radiación ionizante sobre dispositivos reconfigurables

El objetivo de este proyecto es el estudio de los efectos que la radiación ionizante de alta energía produce en los reconfigurables o FPGAs. La importancia de este trabajo a la tendencia cada vez más creciente a utilizar dispositivos reconfigurables en diseños de alta complejidad por sus características únicas de poder ser reconfigurados sin desconectar el funcionamiento del sistema.CONACYT - Consejo Nacional de Ciencias y TecnologíaPROCIENCI