Perfusion Decellularization of Extrahepatic Bile Duct Allows Tissue-Engineered Scaffold Generation by Preserving Matrix Architecture and Cytocompatibility

Reconstruction of bile ducts damaged remains a vexing medical problem. Surgeons have few options when it comes to a long segment reconstruction of the bile duct. Biological scaffolds of decellularized biliary origin may offer an approach to support the replace of bile ducts. Our objective was to obtain an extracellular matrix scaffold derived from porcine extrahepatic bile ducts (dECM-BD) and to analyze its biological and biochemical properties. The efficiency of the tailored perfusion decellularization process was assessed through histology stainings. Results from 4’-6-diamidino-2-phenylindole (DAPI), Hematoxylin and Eosin (H&E) stainings, and deoxyribonucleic acid (DNA) quantification showed proper extracellular matrix (ECM) decellularization with an effectiveness of 98%. Immunohistochemistry results indicate an effective decrease in immunogenic marker as human leukocyte antigens (HLA-A) and Cytokeratin 7 (CK7) proteins. The ECM of the bile duct was preserved according to Masson and Herovici stainings. Data derived from scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) showed the preservation of the dECM-BD hierarchical structures. Cytotoxicity of dECM-BD was null, with cells able to infiltrate the scaffold. In this work, we standardized a decellularization method that allows one to obtain a natural bile duct scaffold with hierarchical ultrastructure preservation and adequate cytocompatibility

La renovación de la palabra en el bicentenario de la Argentina : los colores de la mirada lingüística

El libro reúne trabajos en los que se exponen resultados de investigaciones presentadas por investigadores de Argentina, Chile, Brasil, España, Italia y Alemania en el XII Congreso de la Sociedad Argentina de Lingüística (SAL), Bicentenario: la renovación de la palabra, realizado en Mendoza, Argentina, entre el 6 y el 9 de abril de 2010. Las temáticas abordadas en los 167 capítulos muestran las grandes líneas de investigación que se desarrollan fundamentalmente en nuestro país, pero también en los otros países mencionados arriba, y señalan además las áreas que recién se inician, con poca tradición en nuestro país y que deberían fomentarse. Los trabajos aquí publicados se enmarcan dentro de las siguientes disciplinas y/o campos de investigación: Fonología, Sintaxis, Semántica y Pragmática, Lingüística Cognitiva, Análisis del Discurso, Psicolingüística, Adquisición de la Lengua, Sociolingüística y Dialectología, Didáctica de la lengua, Lingüística Aplicada, Lingüística Computacional, Historia de la Lengua y la Lingüística, Lenguas Aborígenes, Filosofía del Lenguaje, Lexicología y Terminología

Metabolic and enzymatic changes associated with carbon mobilization, utilization and replenishment triggered in grain amaranth (<it>Amaranthus cruentus</it>) in response to partial defoliation by mechanical injury or insect herbivory

Abstract Background Amaranthus cruentus and A. hypochondriacus are crop plants grown for grain production in subtropical countries. Recently, the generation of large-scale transcriptomic data opened the possibility to study representative genes of primary metabolism to gain a better understanding of the biochemical mechanisms underlying tolerance to defoliation in these species. A multi-level approach was followed involving gene expression analysis, enzyme activity and metabolite measurements. Results Defoliation by insect herbivory (HD) or mechanical damage (MD) led to a rapid and transient reduction of non-structural carbohydrates (NSC) in all tissues examined. This correlated with a short-term induction of foliar sucrolytic activity, differential gene expression of a vacuolar invertase and its inhibitor, and induction of a sucrose transporter gene. Leaf starch in defoliated plants correlated negatively with amylolytic activity and expression of a β-amylase-1 gene and positively with a soluble starch synthase gene. Fatty-acid accumulation in roots coincided with a high expression of a phosphoenolpyruvate/phosphate transporter gene. In all tissues there was a long-term replenishment of most metabolite pools, which allowed damaged plants to maintain unaltered growth and grain yield. Promoter analysis of ADP-glucose pyrophosphorylase and vacuolar invertase genes indicated the presence of cis-regulatory elements that supported their responsiveness to defoliation. HD and MD had differential effects on transcripts, enzyme activities and metabolites. However, the correlation between transcript abundance and enzymatic activities was very limited. A better correlation was found between enzymes, metabolite levels and growth and reproductive parameters. Conclusions It is concluded that a rapid reduction of NSC reserves in leaves, stems and roots followed by their long-term recovery underlies tolerance to defoliation in grain amaranth. This requires the coordinate action of genes/enzymes that are differentially affected by the way leaf damage is performed. Defoliation tolerance in grain is a complex process that can’t be fully explained at the transcriptomic level only.</p

Expresión de genes relacionados con defensa en plantas de tomate durante la fase presimbiótica de la simbiosis micorrízica arbuscular

La mayoría de las plantas angioespermas forman una asociación simbiótica con los hongos micorrízicos arbusculares (HMA). Se ha observado que en esta simbiosis ocurre una supresión o una regulación de las respuestas de defensa para permitir la colonización micorrízica, relacionada con la degradación de los fragmentos de quitooligosacáridos por las quitinasas micorriza-específica. En este trabajo se describe el efecto del uso exógeno de la sistemina sobre el proceso de micorrización. Se observó un efecto diferencial de los HMA (G. cubense, F. mosseae y R. intraradices) sobre la actividad de las b-glucanasas y las quitinasas a las 12 horas de inducción, en las raíces del tomate, potenciada por la aplicación de la sistemina. La hormona polipeptídica indujo la expresión rápida de una batería de genes relacionados con los procesos de señalización y respuestas de defensa en tomate; sin embargo, su acción conjunta con los HMA moduló, de forma diferenciada, la expresión génica. Se observó la inducción de los genes RbohD, LoxD y PLA2 en las primeras dos horas después de la aplicación del HMA y de la sistemina. Estos resultados sugieren un papel de las oxylipinas y la especie reactiva del oxígeno en el proceso inicial del reconocimiento. Por otra parte, se demuestra que la sistemina, aplicada de forma exógena, está siendo percibida en las raíces donde modula las respuestas de defensa local en el proceso de micorrización

Development and yield traits indicate that the constitutive wound response phenotype of prosystemin overexpressing tomato plants entails no fitness penalty.

Systemin is a peptide hormone that regulates the wound response in tomato plants. Consequently, the overexpression of its prosystemin (ProSys) precursor protein leads to a resource-demanding constitutive activation of tomato’s wound-response. According to the growth vs. defense resource allocation premise, ProSys overexpression should negatively affect the physiological fitness of tomato plants. The present study was performed to explore why the opposite effect was steadily observed, instead. It was based on the premise that a better understanding of this unexpected outcome could help establish improved wound and related defense responses without negatively affecting crop productivity. To this effect, an experimental strategy was deployed to measure various physiological, biochemical and molecular parameters associated with either development, productivity, defense or in combination in untransformed (WT) and ProSys overexpressing (ProSys-OE) tomato plants. Thus, the chlorophyll fluorescence data obtained from plants grown under greenhouse experiments indicated that photosynthetic performance was not affected in ProSys-OE plants which also grew 7–14% taller than WT plants. Moreover, they showed accelerated flowering and yielded fruits of increased size (7–16% taller and wider) and weight (16–58% heavier), with modified fruit quality in terms of firmness (28% higher), titratable acidity (27–32% higher) and chemical composition. These findings suggest two complementary possibilities: (i) systemin is able to modulate both the wound response and plant development through the activation of jasmonic acid biosynthesis and signaling, and (ii) ProSys, an intrinsically disordered protein, acts as a signaling hub to regulate development and defense programs. These results shed light on the understanding of this plant regulatory mechanism and further suggest that systemin/ProSys-based regulation is central to control the defense-development balance in tomato. This knowledge could eventually lead to improved and more environmentally sound agricultural production practices

Calculo del impuesto empresarial a tasa única para maquiladoras

Seminario: Estudio y aplicación de los impuestos en Méxic

Betacyanin Biosynthetic Genes and Enzymes Are Differentially Induced by (a)biotic Stress in <i>Amaranthus hypochondriacus</i>

<div><p>An analysis of key genes and enzymes of the betacyanin biosynthetic pathway in <i>Amaranthus hypochondriacus</i> (<i>Ah</i>) was performed. Complete cDNA sequence of <i>Ah</i> genes coding for cyclo-DOPA 5-O glucosyltransferase (<i>AhcDOPA5-GT</i>), two 4, 5-DOPA-extradiol-dioxygenase isoforms (<i>AhDODA-1</i> and <i>AhDODA-2</i>, respectively), and a betanidin 5-<i>O</i>-glucosyltransferase (<i>AhB5-GT</i>), plus the partial sequence of an orthologue of the cytochrome P-450 <i>R</i> gene (<i>CYP76AD1</i>) were obtained. With the exception <i>AhDODA-2</i>, which had a closer phylogenetic relationship to <i>DODA-like</i> genes in anthocyanin-synthesizing plants, all genes analyzed closely resembled those reported in related Caryophyllales species. The measurement of basal gene expression levels, in addition to the DOPA oxidase tyrosinase (DOT) activity, in different tissues of three <i>Ah</i> genotypes having contrasting pigmentation levels (green to red-purple) was determined. Additional analyses were performed in <i>Ah</i> plants subjected to salt and drought stress and to two different insect herbivory regimes. Basal pigmentation accumulation in leaves, stems and roots of betacyanic plants correlated with higher expression levels of <i>AhDODA-1</i> and <i>AhB5-GT</i>, whereas DOT activity levels coincided with pigment accumulation in stems and roots and with the acyanic nature of green plants, respectively, but not with pigmentation in leaves. Although the abiotic stress treatments tested produced changes in pigment levels in different tissues, pigment accumulation was the highest in leaves and stems of drought stressed betacyanic plants, respectively. However, tissue pigment accumulation in stressed <i>Ah</i> plants did not always correlate with betacyanin biosynthetic gene expression levels and/or DOT activity. This effect was tissue- and genotype-dependent, and further suggested that other unexamined factors were influencing pigment content in stressed <i>Ah</i>. The results obtained from the insect herbivory assays, particularly in acyanic plants, also support the proposal that these genes could have functions other than betacyanin biosynthesis.</p></div

Expression of betacyanin biosynthetic genes in response to water stress.

<p>Relative expression levels² were determined in leaves, stems and roots of <i>A. hypochondriacus</i> plants, with contrasting pigmentation patterns, subjected to water stress. Induced or repressed levels of expression (i.e. relative expression ≥1.5 or ≤0.5) are shown in bold text and italics, respectively.</p>1<p>The genotypes examined in this study were <i>Ah</i> cv. Nutrisol (<i>AhNut</i>; with predominantly betacyanic leaves), <i>Ah</i> India Red (<i>AhIR</i>; with predominantly betacyanic stems) and <i>Ah</i> India Green (<i>AhIG</i>; with all tissues acyanic).</p>2<p>The fold change in the expression of the target genes was calculated using the 2^−ΔΔCt method according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099012#pone.0099012-Livak1" target="_blank">[76]</a>.</p

Expression of betacyanin biosynthetic genes in response to <i>discontinuous</i> insect herbivory.

<p>Relative expression levels³ were determined in stems of <i>A. hypochondriacus</i> plants, with contrasting pigmentation patterns, subjected to insect herbivory. Induced or repressed levels of expression (i.e. relative expression ≥1.5 or ≤0.5) are shown in bold text and italics, respectively.</p>1<p>h =  time, in hours, spent on the plant by the feeding larvae before they were removed and the tissues sampled.</p>2<p>The genotypes examined in this study were <i>Ah</i> cv. Nutrisol (<i>AhNut</i>; with predominantly betacyanic leaves), <i>Ah</i> India Red (<i>AhIR</i>; with predominantly betacyanic stems) and <i>Ah</i> India Green (<i>AhIG</i>; with all tissues acyanic).</p>3<p>The fold change in the expression of the target genes was calculated using the 2^−ΔΔCt method according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099012#pone.0099012-Livak1" target="_blank">[76]</a>.</p