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

A dimeric inhibitor of insect a-amylase from barley. Cloning of the cDNA and identification of the protein

A cDNA clone, designated pUP-44, whose longest open reading frame codes for a protein that is homologous to the wheat α-amylase inhibitors, has been isolated from a library obtained from developing barley endosperm. The deduced sequence for the mature protein, which is 122 residues long, is preceded by a sequence of 30 residues which has the typical features of a signal peptide. A closely corresponding protein, designated BDAI-1, has been isolated from mature endosperm. BDAI-1 behaves as a dimer and inhibits the α-amylase from the insect Tenebrio molitor at concentrations that have no effect on salivary or pancreatic α-amylases

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

CM-proteins and thionins in cereals: characterization and cloning of cDNA

The study of cereal albumins and globulins has lagged somewhat behind that of the prolamins, which nave been considered as typical reserve proteins. However, these protein fractions merit closer attention for a variety of reasons. The main individual albumins and globulins are at least as abundant as many prolamin components, and it can be speculated that in a tissue, such as the cereal endosperm, which is completely consumed during germination, al 1 abundant proteins may play a reserve role. They have also a higher proportion of essential amino acids, as compared with the prolamins, and thus may be releyant in connec^ tion with the genetic alteration of overall grain composition. Finally, a high proportion of the main components of these protein fractions have inhibitory and even toxic properties, which may be related to the protection of this tissue during development and germination, and might influence the nutritional valué of the cereal products. We report here the characterization in barley of cDNA clones encoding two major groups of proteins: the CM-proteins, a family that inciudes inhibitors of trypsin and a-amylase, and the thionins, a group of high-lysine toxic polypeptides

Chromosomal location and expression of genes encoding low molecular weight proteins in wheat and related species

A review of recent work on the chromosomal location and expression of genes encoding moderately abundant, presumably non-storage endosperm proteins from wheat, barley and rye is presented. Related aspects, such as regulatory genetic effects, in vivo and in vitro synthesis, types of processing, deposition sites, and molecular cloning are also discussed. The relevance of these studies in connection with basic endosperm biology, genetic manipulation of quality and agronomic traits, and the evolution of these important crops is briefly emphasized

Educación en los Objetivos de Desarrollo Sostenible (ODS) de la Agenda 2030, a través de la red de huertos escolares comunitarios HecoUSAL

Memoria ID-023. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2018-2019

Evolutionary learning using a sensitivity-accuracy approach for classification

Accuracy alone is insufficient to evaluate the performance of a classifier especially when the number of classes increases. This paper proposes an approach to deal with multi-class problems based on Accuracy (C) and Sensitivity (S). We use the differential evolution algorithm and the ELM-algorithm (Extreme Learning Machine) to obtain multi-classifiers with a high classification rate level in the global dataset with an acceptable level of accuracy for each class. This methodology is applied to solve four benchmark classification problems and obtains promising results

Economics of gastroenteropancreatic neuroendocrine tumors : a systematic review

Despite current interest, enthusiasm and progress in the development of therapies for gastroenteropancreatic (GEP) neuroendocrine tumors (NETs), there are substantial gaps in the published literature regarding cost-of-illness analyses, economic evaluation and budget impact analyses. Compounding the issue is that data on resource utilization and cost-effectiveness of different diagnostic and therapeutic modalities for GEP-NETs are scarce. A systematic review on the economic impact of GEP-NETs was carried out using four databases: EMBASE, PubMed, the National Health Service Economic Evaluation Database and Cochrane review. Fully published articles from January 2000 to May 2017, in English and Spanish, were included. All articles that satisfied the inclusion criteria were included in the systematic review; summary descriptive statistics were used to describe the methodological characteristics. The 14 studies selected included cost-of-illness analyses (n = 4), economic evaluations (n = 7) and budget impact analyses (n = 3). Almost all studies were performed in the United States. Healthcare costs for patients with NETs included medication, outpatient visits, hospitalizations, and check-ups/tests. Reducing adverse events is an area where cost savings could be achieved; however, there was not enough evidence on the cost impact of adverse events. There is a lack of data related to resource utilization in the field of GEP-NETs. Therefore, cost-effectiveness and budget impact studies of existing and emerging treatments are urgently needed to help the decision-making process for patients with NETs