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Introducción: La alta prevalencia de hipertensión arterial (HTA) es un problema de salud pública a nivel global. Diversas condiciones comprometen un adecuado control de esta enfermedad, siendo una de reciente interés las alteraciones del sueño. Describimos mediante una revisión narrativa los hallazgos recientes en la literatura acerca de los efectos de la calidad y cantidad de horas de sueño en pacientes hipertensos. Se seleccionaron 18 artículos que cumplieron los criterios de inclusión para esta revisión. En la presente revisión se detallarán los hallazgos encontrados en relación con las complicaciones que guardan relación con la duración y calidad del sueño en pacientes con HTA, así como factores predictores de una mala calidad del sueño en estos pacientes.

Xyloglucan oligosaccharides (XGOs), derived from the hydrolysis of plant cell wall xyloglucan, are a novel class of biostimulants that exert positive effects on plant growth and morphology and can enhance plant stress tolerance. The aim of this study was to determine the influence of the application of exogenous Tamarindus indica L. cell wall-derived XGOs on Nicotiana tabacum L. tolerance to salt stress by evaluating morphology, physiological, and metabolic changes. N. tabacum plants were grown in agar-gelled media for 2 mo under salt stress with 100 mM of sodium chloride (NaCl) ± 0.1 μM XGOs. The germination percentage (GP), number of leaves (NL), foliar area (FA), primary root length (PRL), and density of lateral roots (DLR) were measured. In addition, unaffected 21-d-old N. tabacum plants were treated with a salt shock (100 mM NaCl) ± 0.1 μM XGOs. Proline, total chlorophyll, and total carbonyl levels, in addition to lipid peroxidation degree and activities of four enzymes related to oxidative stress, were quantified. The results indicated that XGOs significantly improved N. tabacum plants development after exposure to salt stress. XGOs caused a significant increase in NL and PRL, promoted lateral root formation, and produced an increase in proline and total chlorophyll contents, while reducing protein oxidation and lipid peroxidation. Although the XGOs modulated the activity of the enzymes analyzed, they were not statistically different from the salt control. It was concluded that XGOs may act as metabolic inducers that trigger the physiological responses that counteract the negative effects of oxidative stress under saline conditions.

Introduction.Legume nodulation is regulated by the exchange of molecular signals between the plant and rhizobia. The bacterial nodulation genes are activated by flavonoids present in root exudates. As a result of this activation, the Nod factors are synthesized, which in turn participate in the morphogenesis and function of the nodules. It is then possible to regulate the induction of Nod factors and other signals related to the nodulation process, during the inoculants production.Objective.To determine if the moment to induce the nodulation genes inBradyrhizobiuminoculants affects the synthesis of compounds related to the nodulation process and its interaction with soybean plants.Materials and methods.The research was developed in Rizobacter S.A., Argentina and Fyteko S.A. laboratories, Belgium, and in a plant growth chamber of the first one, during May-June of 2017. TwoBradyrhizobiumstrains were induced with daidzein in three moments. The signals produced by the strains and the biological effect in soybean plants were studied.Results.Differences were detected in the molecules produced by the bacteria, but it did not affect the growing and plants nodulation related to the different moments of induction.Conclusion.The metabolites excreted byBradyrhizobiumchanged with strain and induction moment, although the latter did not affect nodulation or soybean plants growth. Introducción.La nodulación en leguminosas está regulada por el intercambio de señales moleculares entre la planta y los rizobios. Los genes de nodulación de la bacteria son activados por flavonoides presentes en los exudados de las raíces. Como resultado de esa activación se sintetizan los factores Nod, que a su vez participan en la morfogénesis y función de los nódulos. Es posible regular entonces, la inducción de factores Nod y de otras señales relacionadas con el proceso de nodulación, durante la producción de inoculantes.Objetivo.Determinar si el momento de inducir los genes de nodulación en inoculantes deBradyrhizobiumafecta la síntesis de compuestos relacionados con el proceso de nodulación y su interacción con plantas de soya.Materiales y métodos. La investigación se desarrolló en los laboratorios de dos empresas: Rizobacter S.A., Argentina y Fyteko S.A., Bélgica, así como en una cámara de crecimiento de plantas de la primera empresa, durante mayo y junio del año 2017. Dos cepas deBradyrhizobiumfueron inducidas con daidzeína en tres momentos. Se estudiaron las señales producidas por las cepas y el efecto biológico en las plantas de soya.Resultados.Se detectaron diferencias en las moléculas producidas por las bacterias, pero no en el crecimiento y la nodulación de las plantas, relacionado con los diferentes momentos de inducción.Conclusión.Los metabolitos excretados porBradyrhizobiumvariaron con la cepa y el momento de la inducción, aunque este último no afectó la nodulación ni el crecimiento de las plantas de soya.

The ability of cyanobacterium Arthrospira sp. to assimilate waste nitrogen sources (ammonium and urea) makes it an important candidate for wastewater management. The aim of this work was to evaluate a cultivation approach based on continuous-transitional-feeding regime (nitrate-ammonium-nitrate) in a photobioreactor to assess the effects of ammonium salts on Arthrospira sp. PCC 8005 metabolism. Using a comprehensive biochemical, proteomic and stoichiometric profiling of biomass, this study demonstrated that the proposed cultivation approach could increase the proteins and pigments yields by 20-30%, compared to the respective yields obtained from wild-type Arthrospira sp. strain A light-energy-transfer model was used to predict the biomass and oxygen productivities of Arthrospira sp. cultivated under transitional-feeding regime. 95 ± 2% match was observed between the experimental and simulated productivities. This study thus opened new avenues for use of ammonium rich wastewater for commercial production of high value pigments, biofuel and bioplastics using Arthrospira sp.

Al acercarnos al fenómeno del fútbol en una época como la nuestra, resulta apropiado hablar más bien de los fútboles que del fútbol. En el mundo actual, tan abierto a procesos de globalización e internacionalización que, sin embargo, no logran homogeneizar las prácticas culturales de los seres humanos, debemos mantener una mirada abierta hacia interpretaciones particulares de los fenómenos sociales. El deporte, entendido como una práctica cultural significante, guarda una serie de implicaciones particulares para quienes participan de él desde cualquiera de sus múltiples facetas. Facetas que fluctúan dinámicamente desde el ejercicio profesional de determinada forma deportiva, hasta la afición pasiva por un cierto deportista o grupo de deportistas. As we approach the phenomenon of football at a time like ours, it is appropriate to speak rather of soccer than of soccer. In today's world, so open to globalization and internationalization processes that, however, fail to homogenize the practices cultural values ​​of human beings, we must maintain a open gaze towards particular interpretations of the social phenomena. Sport, understood as a significant cultural practice, has a series of implications particular for those who participate in it from any of its many facets. Fluctuating facets dynamically from the professional practice of certain sports form, even the passive fondness for a certain athlete or group of athletes.

The aim of the present study was to evaluate the effects of varying concentrations of different nitrogen sources (individually or in combination) on the biochemical, transcriptomic and proteomic profiles of Arthrospira sp. PCC 8005 under batch and continuous modes. In batch mode, while ammonium showed a repressive effect on nitrate-assimilation pathway of the cyanobacteria; better growth and nutrient uptake rate were observed in presence of urea than nitrate. The inhibitory effect of ammonium was further confirmed by the continuous photobioreactor study wherein the nutrient feed was transiently replaced from nitrate to ammonium (28mM turbiostat regime). The changes in lipid, exopolysaccharide, transcriptomic and proteomic profiles of cyanobacteria on transition from nitrate to ammonium indicated at an onset of nutrient stress.

Soil salinity is one of the most devastating problems which reduces crop production and increases desertification. New approaches to overcome the negative effect of salinity on plants include the use of plant biostimulants, such as Xyloglucan oligosaccharides (XGOs) derived from the breakdown of xyloglucans from plant cell walls. The present study aimed at verifying the influence of exogenous XGOs derived from Tamarindus indica L. cell walls, on Arabidopsis thaliana’s tolerance to salt stress by understanding the gene expression, enzymatic and metabolic changes resulting from its application. A. thaliana plants were grown in liquid media and after 15 days they were treated by a salt shock with 100 mM of sodium chloride, with or without XGOs at 0.1 mg L-1. Gene expression of four oxidative stress markers as well as catalase and peroxidase activities and content of glutathione, total carbonyl, polyphenolics and chlorophyll were quantified. Bioinformatic models were used to obtain the co-expression network of the four oxidative stress response gene markers from microarray data of Arabidopsis under salt stress. Results showed that in saline conditions, XGOs dramatically increased catalase gene expression and enzymatic activity, peroxidase activity, and chlorophyll a/b ratio, while reducing protein oxidation and total polyphenols. Thus, XGOs may act to counteract negative effects of oxidative stress under saline conditions.

The influence of chitosaccharides on the symbiotic interaction between Bradyrhizobium and soybean was examined. The results show that chitosaccharides either positively or negatively affect soybean nodulation or plant growth depending on their molecular weight, concentration and the application methods. When directly added to the in vitro culture media, chitosan of high molecular weight inhibit Bradyrhizobium viability in a dose dependent manner while chitooligosaccharides reduce slightly the bacteria viability only at concentration equal or higher than 50 mg·L-1. Chitooligosaccharides significantly enhance nodule formation and dry mass in soybean roots at doses between 10 and 100 mg·L-1. Both types of chitosaccharides, at the highest doses (>500 mg·L-1), negatively affect plant height and root size, whereas medium doses (50 to 100 mg·L-1) increase slightly leave number. Under field conditions, foliar application of both chitosaccharides enhances growth and nodulation of soybean plants. Nevertheless, using this application method, chitosan remains more effective than chitooligosaccharides.

Algae biomass is nowadays considered as a unique reservoir of a huge variety of different molecules, such as lipids, carbohydrates, proteins and secondary metabolites, awaiting development in various fields. In particular, the valorization of the algae polysaccharide content is still in its infancy and intense research activity is starting to appear. Oligosaccharides with defined molecular weight and structures are extremely interesting for different applications such as plant biostimulation or biopesticide. Oligosaccharide are often prepared in medium to large scale upon chemical-based hydrolysis reactions from the extracted polysaccharides in harsh conditions (temperature and pH), leading to the loss of the fragile groups such as the sulfate functions in carrageenans. In the present work, microwave-based hydrolysis, as a green chemistry method, is optimized to produce bioactive oligosaccharides from carrageenans. Microwave hydrolysis process is first optimized on a commercially available carrageenan and further applied on carrageenans extracted from two algae, namely Kappaphycus alvarezii or Eucheuma spinosum that are produced in large quantities in the world and have a high content of carrageenans. We also develop a complete set of characterization methods, i.e. size exclusion chromatography, reducing sugar and residual sulfate determination and mass spectrometry, to perform the follow-up of the hydrolysis reaction. We here demonstrate that fast (5 min) and controlled hydrolysis of carrageenans can be achieved in pure water under microwave activation, while preserving the nature of the active sulfate groups (>95%).

En este artículo me aproximo a una de las primeras construcciones discursivas de la historia de la Nueva España, el poema Nuevo mundo y conquista, escrito por el criollo novohispano Francisco de Terrazas a finales del siglo xvi. Para esto, se expone brevemente la constitución de una clase criolla, heredera del sentimiento de hidalguía de los primeros conquistadores de América, y posteriormente se analiza la escritura de Nuevo mundo y conquista en el marco de estas consideraciones.

Resumen Los exudados radiculares son metabolitos secundarios secretados por la raiz, que cumplen diferentes funciones en la naturaleza. En la literatura, existe poca informacion sobre el efecto de estas sustancias en la biota del suelo. En esta investigacion se estudia el efecto de los exudados de cinco ecotipos de “higuerilla” Ricinus communis L. (Euphorbiaceae) sobre las larvas de primer estadio de Gymnetis bonplandii Schaum (Coleoptera, Scarabaeidae), una plaga subterranea muy comun en suelos con alto contenido de materia organica. Los cinco ecotipos de “higuerilla” fueron sembrados en bolsas de polietileno en un diseno completo al azar con nueve repeticiones y un testigo. Dos larvas de primer estadio provenientes de una crianza de laboratorio fueron acondicionadas en jaulas disenadas especialmente para confinar larvas en el suelo. A los siete dias se evaluo la mortalidad de las larvas y los datos fueron corregidos considerando la mortalidad natural con la formula Schneider-Orelli, previo al ANVA y la prueba de comparacion de Duncan usando el programa SPSS. Los resultados indicaron que los cinco ecotipos tuvieron efecto letal sobre las larvas de primer estadio de G. bonplandii Schaum y el rango de mortalidad oscilo entre el 30 y 90 %, pudiendo ser utilizados como componentes biologicos en el manejo de plagas. Palabras clave: exudados radiculares, Ricinus communis , Euphorbiaceae, Gymnetis bonplandii , Coleoptera, Scarabaeidae. Abstract Root exudates are secondary metabolites secreted by the root, which have different functions in nature. In the literature, there is little information about the effect of these substances on underground biota. In this research, we studied the effect of root exudates of five ecotypes of “castor oil plant” Ricinus communis L. (Euphorbiaceae) on the first instar larvae of Gymnetis bonplandii Schaum (Coleoptera, Scarabaeidae), a common underground pest under high organic matter soil. The five ecotypes of "castor oil plant" were planted in polyethylene bags in a random complete design with nine replicates and a control. Two first instar larvae from laboratory breeding were conditioned in specially designed cages to confine larvae in the soil. Data of seven-day larval mortality was corrected considering natural mortality using Schneider-Orelli’s formula prior to ANOVA and Duncan comparison test using the SPSS statistical program. These results indicate that the five ecotypes had lethal effect on first instar larvae of G. bonplandii Schaum and mortality ranged between 30 and 90 %, therefore they may be used as biological components in pest management. Keywords: root exudates, Ricinus communis , Euphorbiaceae, Gymnetis bonplandii , Coleoptera, Scarabaeidae.

Oligosaccharins are potent biomolecules which activate defense responses and resistance in tobacco plants. However, it is not known the systemic behavior of defensive enzymes activated by these elicitors. In this work, the dynamic behavior of key defensive enzymes was evaluated in tobacco plant leaves previously treated through the roots with chitosan polymer (CH), chitosan (COS) and pectic (OGAS) oligosaccharides and Spermine (Sp). All macromolecules tested activated protein levels and defense enzymatic activity in tobacco leaves but with different response dynamics among them and depending on the biochemical variable evaluated. Defense response above control levels were detected since 12 hours after treatments and it consisted in a biphasic behavior with two peaks for PAL (EC 4.3.1.5) and β 1 - 3 glucanase (EC 3.2.1.6) enzymatic activities. The highest enzymatic levels for these enzymes were achieved at 48 hours in plantlets elicited with COS and at 72 hours for those plants treated with chitosan polymer, while the highest POD (EC 1.11.1.6) activity was detected with CH between 48 and 72 hours. These results demonstrated systemic defense activation by oligosaccharins in tobacco whose dynamic of defense response is affected by the kind of oligosaccharins tested. When applying OGAS by foliar spray on tobacco, systemic resistance against Phytoththora nicotianae was induced and plantlets were protected with the low concentration tested by 46% under the bioassays conditions performed. Moreover, enzymatic determinations on roots and leaves previous to plant-pathogen interaction showed increments above 30% of control levels for PAL and POD activities. It means that oligosaccharins activate local and systemic defense responses in plants in the absent of pathogen infection.

The potential use of cell wall derived oligosaccharides as regulators of plant defence, growth and development was already referred to nearly 20 years ago in a first review (Albersheim and Darvill, 1985). These bioactives, called oligosaccharins, are now relatively easy to produce and ready to face public acceptance because of their natural origin. In this review, we summarise the results obtained by a consortium of research institutions and companies working in the preparation, bioactivity studies, and practical use of different oligosaccharides as biostimulants in agriculture. We will start by explaining how fungal cell wall-derived chitosan and chitooligosaccharides stimulate plant defence, growth and improve crop yield and quality of many species. Then we will focus on different oligosaccharides such as oligogalacturonides, prepared from citrus pectin, that can partial or totally substitute phytohormones in the culture “in vitro” of sugar cane, citrus, coffee, tomato, rice and banana plants, reducing the time required for plant propagation, avoiding culture-induced genetic changes and increasing field survival percentage of these plants but also inducing rooting and plant growth. Then we will explain how the use of xyloglucan oligosaccharides, derived from the plant cell wall cannot only promote plant growth but also differentially act on the regulation of diverse biotic and abiotic stress-related genes. We will also discuss several field experiments where the foliar application of lipo-chitooligosaccharides, a nodulation factor in the soybean-rhizobium symbiosis, was shown to be effective in the enhancement of plant growth and production yield in soybean, wheat and corn. In short, this work aims to

In cyanobacteria, the nitrogen and carbon metabolisms are functionally bridged and consequently respond to the carbon-to-nitrogen ratio. Consequently, a nitrogen deficiency results in carbon excess. For the first time, the biological adaptation of Arthrospira sp. PCC 8005 to nitrogen starvation has been deeply characterized at the cellular structure scale. The results indicated that the carbon excess is rerouted into carbon storage granules, such as the polyhydroxyalkanoate and glycogen granules corroborating existing data. Additionally, this photosynthetic organism hugely secreted exopolysaccharides, which could constitute another biological carbon reservoir. It has been reported that few cells in trichomes of Arthrospira sp. PCC 8005 still display a high level of fluorescence after a long-term nitrogen starvation. The transmission electron microscopy showed that some cells still contained thylakoids and phycobilisomes after this long-term nitrogen starvation, which could explain the remaining fluorescence.

The aim was to test promotive effects of oligosaccharins on root growth and development at the root apical meristem and the cell cycle using the model systems, Arabidopsis thaliana and the tobacco (Nicotiana tabacum) BY-2 cell line. Arabidopsis was grown on medium supplemented with 0.1 mg L−1 oligoxyloglucan (OX), 10 mg L−1 Pectimorf® (P) or 0.5 mg L−1 indole butyric acid (IBA). Primary root length, number of lateral root primordia, root apical meristem (RAM) length and epidermal cell length were recorded. Three genotypes were used: wild type (WT) and transgenic lines expressing either Schizosaccharomyces pombe (Sp) cdc25 or over-expressing(oe) Arath;WEE1. All treatments promoted primary root elongation but repressed lateral root production. Only P had a clear positive effect on meristem length whereas all other genotype × treatment interactions showed shorter RAMs. Whilst IBA, OX and P induced an increase in cell length in Spcdc25, the same treatments caused a significant decrease in WEE1 oe . Mitotic indices were also significantly higher in roots treated with oligosaccharins suggesting a shortening of the cell cycle. This hypothesis was tested in the BY-2 cell line. Both OX and P shortened the cell cycle exclusively through a shortening of G1 whilst mitotic cell size remained constant between treatments. In conclusion, both OX and P do indeed stimulate growth and shorten the cell cycle in higher plants and at the cellular level are able to reverse large and small cell size phenotypes normally exhibited by WEE1 oe and Spcdc25 genotypes, respectively.

Enzymatic defense responses and protection against Phytophthora nicotianae were studied in tobacco plants treated with chitosan of different molecular weights (MW) and degrees of acetylation (DA). The concentration and mode of chitosan application affected enzymatic induction in tobacco leaves. β-1,3-Glucanase (EC 3.2.1.6) activity required 10 times the polymer concentration relative to the oligochitosan mixture to induce the highest activity above control when treated by foliar spray, indicating the influence of molecular weight in this response. PAL (EC 4.3.1.5) and POD (EC 1.11.1.6) activities increased above control as a result of the influence of polymer degree of acetylation when treatments were applied by foliar spray. A higher DA favored PAL activity, whereas a lower DA induced higher POD activity. Using an in vitro bioassay, it was found that the three chitosan compounds caused a reduction of the infection index of P. nicotianae in tobacco plants that was dependent on elicitor concentrations. There was a significant relationship between the reduction of the infection index and an increase in PAL activity when chitosan was applied by foliar spray and by substrate drench to the plant rhizosphere. These results demonstrate the influence of chitosan physico–chemical properties in plant-induced resistance and the relevance of particular responses in plant protection against pathogens.

Cell walls polysaccharides from murta fruit (Ugni molinae Turcz), an endemic Chilean species with relevant food uses, were fractionated by water, ammonium oxalate, hot diluted HCl and cold diluted NaOH extractions. The polysaccharide fractions were analysed for monosaccharide composition and physicochemical properties. Pectic substances were found in all extracts, but mainly in the oxalate and acid soluble fractions, in which they appear as homogalacturonan polymers. Murta pectin was further extracted by hot diluted acid treatment using industrial conditions, yielding 30% by weight of dry fruit. The polymer showed similar composition and physicochemical properties to those of commercial citrus pectin, presenting a galacturonic acid content of 70.9% (w/w), a molecular weight of 597. kDa, and a methoxylation degree of 57%. The FT-IR spectrum of murta pectin suggests the presence of ferulic acid residues on its structure and the NMR analysis confirmed the structure of this polysaccharide. It is concluded that murta fruit can be considered as a valuable source of high quality pectin.

Plant cell walls undergo remodeling during growth and development and are the first target of many invading pathogens. Acidic pectin (homogalacturonans) binds calcium and forms chain dimers called egg boxes and even multimers at higher calcium ion concentrations. Chitosan, the deacetylated form of chitin produced by fungi when invading plant tissues, is a cationic polymer that can interact with negatively charged pectin. The interaction between chitosan oligomers (COS) and pectic egg boxes was investigated using 2F4, a monoclonal antibody specific for calcium-associated dimers of pectin. Depending on the size of the pectic molecules, the COS to pectin ratio, the degree of polymerization and the degree of acetylation of COS in the mixture, the calcium-induced egg box conformation of oligogalacturonides (OGA) was strongly stabilized or destroyed. The biological activity of COS-stabilized egg boxes was assayed on Arabidopsis cell suspensions. COS-OGA egg boxes strongly enhanced extracellular alkalinization and decreased potassium fluxes compared to control COS and OGA alone. Furthermore, OGA rescued Arabidopsis from cell death induced by higher concentrations of deacetylated COS. The stabilized COS-OGA egg boxes could constitute a combined emergency signal that informs plant cells on both cell wall degradation and pathogen presence, triggering a much stronger response than individual components alone.

This study aims at establishing the maturation of the digestive system in Robsonella fontaniana by means of measuring the digestive enzyme activity in paralarvae after hatching. Different groups of newly hatched paralarvae were fed with Artemia sp. (FA), Lithodes santolla zoea (FL) or were starved to serve as negative control (ST), the experimental period lasted 27 days after hatching (DAH). The semi-quantitative assay api(A (R)) ZYM (bioM,rieux, France) was used to identify the pool of digestive enzymes present in paralarvae prior to selecting the specific enzymes acid phosphatase, total protease, trypsin and chymotrypsin for analysis. Mortality and larval protein content were also measured during the experiment. The survival of R. fontaniana hatchlings differed depending on the quality of the diet offered (ST < FA < FL), the same trend was observed with respect to paralarval protein content. Total protease and acid phosphatase activities were not related to either time of development or diet (P < 0.05). However, the activity of trypsin and chymotrypsin after DAH 10 was dependent on diet (P < 0.05). Paralarvae fed with Lithodes zoea (FL) performed better than paralarvae in the other two groups, exhibiting lower mortality, higher protein content and the highest proteolytic activity for trypsin and chymotrypsin. The results indicate that Lithodes-larvae are a better diet for R. fontaniana paralarvae than Artemia sp.

Circular dichroism spectrometry was used on oligogalacturonides (OGAs) and showed the existence of a calcium/sodium-induced conformational state that is intermediate between single-isolated chains and calcium-associated multimer chains. This conformation is interpreted as being egg box dimers. Using the 2F4 monoclonal antibody that specifically binds such an egg box dimer conformation of pectin, the stability of OGA dimers was investigated over a period of 24 hours. The extent to which egg box dimers were recognized by the antibody was dependent on the temperature and duration of preincubation of the OGA. This suggests a "maturation" process of the egg-box structure that consists in a progressive increase in the length of the junction sequences between two chains that slide along each other in order to form a maximum number of calcium bridges and dimer ends. The maturation of egg boxes induced both a significant increase in their binding to wall-associated kinase 1 (WAK1) and an increased extracellular alkalinization when applied to Arabidopsis thaliana cell suspensions. The chemical modification of the reducing end of the OGAs largely diminished their elicitating activity but did not hinder either dimerization or binding of these end-reduced egg boxes to WAK1. We conclude that there are at least two different perception systems for egg box dimers. One binds egg box junctions and the other binds egg box ends. The relevance of these results is discussed in terms of pectic signal perception and plant-pathogen interaction.

Enzymatic degradation of chitosan polymer with Pectinex Ultra SPL was used to obtain derivatives with biological potential as protective agents against Phytophthora parasitica nicotianae (Ppn) in tobacco plants. The 24 h hydrolysate showed the highest Ppn antipathogenic activity and the chitosan native polymer the lowest. The in vitro growth inhibition of several Phytophthora parasitica strains by two chitosans of different DA was compared. While less acetylated chitosan (DA 1%) fully inhibited three P. parasitica strains at the doses 500 and 1000 mg/l the second polymer (DA 36.5%) never completely inhibited such strains. When comparing two polymers of similar molecular weight and different DA, again the highest antipathogenic activity was for the less acetylated polymer. However, degraded chitosan always showed the highest pathogen growth inhibition. Additionally, a bioassay in tobacco seedlings to test plant protection against Ppn by foliar application demonstrated that partially acetylated chitosan and its hydrolysate induced systemic resistance and higher levels of glucanase activity than less acetylated chitosan. Similarly, when treatments were applied as seeds coating before planting, about 46% of plant protection was obtained using chitosan hydrolysate. It was concluded that, while less acetylated and degraded chitosan are better for direct inhibition of pathogen growth, partially acetylated and degraded chitosan are suitable to protect tobacco against P. parasitica by systemic induction of plant resistance.

This document is a compilation of the main results obtained in the research project about control systems for didactic plants. The features and processes for modeling and building a prototype, as well as the comparative implementation of several control methods in simulation and on the real physical system are presented. From the expertise about the use of the control techniques in the two degrees of freedom helicopter model, methodological modules for laboratory practices are proposed, such that control students can reinforce the knowledge obtained in lecture classes.

Chitosan oligomers are known elicitors of plant defence mechanisms. In this work, chitooligosaccharides of different degrees of polymerization and degrees of acetylation were prepared and characterized by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The effect of the degree of polymerization (DP), degree of acetylation and concentration of these chitooligosaccharides on defence activation in Arabidopsis thaliana suspension-cultured cells was studied. Our study results show that fully deacetylated chitooligosaccharides (chitosan oligomers) induce, depending on their DP and concentration, phenylalanine ammonia-lyase (PAL) activation, H2O2 synthesis and cell death in A. thaliana cell suspensions. The progressive reacetylation of the chitosan oligomer elicitors progressively impaired their ability to enhance H2O2 accumulation and cell death, but did not affect the activation of PAL.

Chitosan was depolymerized either by HCl hydrolysis or enzymatic degradation with a commercial preparation Pectinex Ultra Spl. The chitooligosaccharides released by both methods were selectively precipitated in methanol solutions and characterized using MALDI-TOF mass spectrometry. Differences between the two methods were detected and concerned the degrees of polymerization of the fragments produced and their acetylation. The enzymatic method yielded shorter fragments with a higher proportion of fully deacetylated chitooligomers. Conversely, acid hydrolysis of the starting chitosan resulted in fragments with degrees of polymerization up to sixteen and more monoacetylated residues than with the enzymatic procedure.

Partially acetylated and methylated oligogalacturonides produced by enzymatic hydrolysis of sugar beet pectin were analysed by negative electrospray ionization ion trap mass spectrometry (ESI-ITMS). The (18)O labelling of the oligomer reducing end allowed the precise assignment of the fragments resulting from glycosidic bond and cross-ring cleavages. The collisional-induced dissociation of the C(i) and Z(j) fragment ions through sequential MS(n) experiments always displayed (0, 2)A-type cross-ring cleavage ions which were related to C(2)H(4)O(2) losses. These (0, 2)A ions appeared to be highly diagnostic ions allowing the precise location of the acetyl groups to the O-2 and/or O-3 of the acetylated galacturonic acid residues.

In the guidelines that institutions of higher education that teach postgraduate studies in Mexico receive from international organizations, as well as those national agencies involved in institutional planning and assessment, the need to train researchers is identified. With this in mind, the question that concerns this article is how to guide the process of learning to research in a doctoral program, based on this guidelines and considering the specific conditions under which it develops? In what follows we show the results of an evaluative research conducted in the PhD in Regional Studies (DER, for its acronym in Spanish) of the Autonomous University of Chiapas (UNACH, for its acronym in Spanish), specifically in the area of training-research that addresses regional educational problems by highlighting positive and negative aspects of its design and implementation. Among the positive aspects, we highlight the strategy implemented for their students to learn to research. Within the negative aspects, we highlight the academic and administrative problems faced in the implementation of this program that is subject to rigid regulatory structures.RESUMENEn los lineamientos que las instituciones de educación superior que imparten estudios de posgrado en México reciben de parte de organismos internacionales, así como de aquellos organismos nacionales que se ocupan de la planea-ción y evaluación institucional, se identifica la necesidad de formar investigadores. Ante esto la pregunta que se responde en este artículo es ¿Cómo orientar el aprendizaje de la investigación en un programa doctoral, teniendo como base estos lineamientos y atendiendo a las condiciones concretas en las que se desarrolla? En las siguientes líneas se presentan los resultados obtenidos en una investigación evaluativa realizada al doctorado en Estudios Regionales (DER) de la Universi-dad Autónoma de Chiapas (UNACH), específicamente en la línea de formación-investigación que aborda los problemas educativos regionales, destacando los aspectos positivos y negativos de su diseño y ejecución. Entre los positivos destaca la estrategia implementada para que sus estudiantes aprendan a investigar, dentro de los negativos los problemas de corte académico-administrativo que enfrenta la implementación de este programa al contar con estructuras normativas rígidas. Contacto principal: pbonals@hotmail.com

El pasado Mundial de fútbol, la FIFA amenazó con sancionar a la selección mexicana de fútbol por lo que le pareció una conducta homófoba realizada por los aficionados mexicanos durante los partidos de su selección contra Camerún y Brasil. La sanción fue retirada antes de ser aplicada, pero el hecho despertó diferentes comentarios tanto por parte de las instituciones implicadas como entre los aficionados y espectadores del evento. Este artículo realiza un análisis del discurso

Xyloglucan oligosaccharides (XGOs) are breakdown products of XGs, the most abundant hemicelluloses of the primary cell walls of non-Poalean species. Treatment of cell cultures or whole plants with XGOs results in accelerated cell elongation and cell division, changes in primary root growth, and a stimulation of defence responses. They may therefore act as signalling molecules regulating plant growth and development. Previous work suggests an interaction with auxins and effects on cell wall loosening, however their mode of action is not fully understood. The effect of an XGO extract from tamarind (Tamarindus indica) on global gene expression was therefore investigated in tobacco BY-2 cells using microarrays. Over 500 genes were differentially regulated with similar numbers and functional classes of genes up- and down-regulated, indicating a complex interaction with the cellular machinery. Up-regulation of a putative XG endotransglycosylase/hydrolase-related (XTH) gene supports the mechanism of XGO action through cell wall loosening. Differential expression of defence-related genes supports a role for XGOs as elicitors. Changes in the expression of genes related to mitotic control and differentiation also support previous work showing that XGOs are mitotic inducers. XGOs also affected expression of several receptor-like kinase genes and transcription factors. Hence, XGOs have significant effects on expression of genes related to cell wall metabolism, signalling, stress responses, cell division and transcriptional control.

Objective: to assess the masticatory performance among complete dental and implant overdenture wearers.Methods: a quasi-experimental study was done. The masticatory efficiency was evaluated in fifteen complete dentures wearers and fifteen upper dentures and lower overdenture wearers. The subjects filled out a satisfaction questionnaire and chewed a piece of 6 g of raw carrots. The particles were issued in the oral cavity and evaluated towers sieves of different diameters superimposed in descending order. Thus the percentage value for each sieve was obtained. The Chi2 or Fisher exact test for qualitative variables and Student t test or Mann-Whitney U for quantitative variables according to their distribution were carriet out. A value of p

Con este artículo culmina la presentación de "Políticas gubernamentales para el desarrollo de la pequeña empresa", informe final de los participantes en el segundo curso sobre las Medidas Administrativas y Manejo Empresarial en la Promoción de la Pequeña Empresa para la República del Perú, realizado en Osaka-Japon, a fines de 1996.

El informe comprende tres temas: el primero relacionado con las políticas gubernamentales para el desarrollo de las Pyme, el segundo con el sistema de financiamiento, y el tercero con los servicios no financieros implementados en el Japón para apoyar a las Pyme. Por la extensión del informe éste se presenta en tres partes correspondiendo a este número de la revista los dos primeros temas.

One of the most innovative approaches for controlling plant diseases is through the enhancement of the plant's own defence mechanisms (induced resistance), which would not involve the application of toxic compounds to plants. It has been well established for over 100 years, that plants can defend themselves; however, in the last 20 years, a significant progress in our knowledge on plant immunity, has provided the understanding required to allow induced resistance to be used in practice. In this chapter we will discuss the bioactivity of chitosaccharides as pathogen associated molecular patterns and their potentiality in crop protection.

Es un reto para la rehabilitación devolver la función y la estética perdida al sistema estomatognático. En el caso de tratamientos complejos, la rehabilitación oral juega un papel clave en el diagnóstico y vela para que se cumplan los objetivos propuestos dentro de parámetros académicos y prácticos. En este reporte se presenta un caso clínico de características complejas rehabilitado mediante prostodoncia parcial fija que requirió el concurso interdisciplinario de endodoncistas, periodoncistas, rehabilitadores orales y laboratoristas dentales. El Síndrome de Colapso de Mordida Posterior (SCMP) bilateral observado se destaca por su gravedad e importancia. El objetivo de este trabajo fue describir de forma integral el diagnóstico y plan de tratamiento en casos complejos realizados con prostodoncia parcial fija en rehabilitación oral y presentar un caso clínico de rehabilitación compleja.[Cabrera JC. Rehabilitación oral con prostodoncia parcial fija: reporte de un caso complejo de arco cruzado. Ustasalud 2012; 11: 45 - 53] It is a challenge for rehabilitation restores lost function and aesthetics stomatognathic system. For complex treatments, oral rehabilitation plays a key role in the diagnosis and ensures that objectives are met within academic and practical settings. This report presents a case of complex features restored by fixed partial prosthodontics requiring interdisciplinary participation of endodontists, periodontists, oral rehabilitation and dental laboratory technicians. The Collapse of Posterior Teeth (CPT) reported stands out for its seriousness and importance. The aim of this report was to describe comprehensively the diagnosis and treatment planning in a complex case performed with fixed partial prosthodontics in oral rehabilitation and present a clinical case of complex rehabilitation.

Sclerotherapy is performed mainly in venous and lymphatic malformations using different substances. Sclerosis in arteriovenous (AV) forms is contraindicated because an erroneous intra-arterial injection may produce extensive necrosis. Classical sclerosis is mainly performed in venous dysplasias with polidocanol, sodium tetradecyl sulphate and ethanol, among others, while in lymphatic malformations, OK-432 is preferred. Sclerotherapy with the microfoam technique significantly improves results.