Leishmania donovani: thionins, plant antimicrobial peptides with leishmanicidal activity

The leishmanicidal activity of plant antibiotic peptides (PAPs) from the principal families, such wheat thionins, a barley lipid transfer protein and potato defensins and snakins were tested in vitro against Leishmania donovani. Only thionins and defensins were active against this human pathogen at a low micromolar range of concentrations. Thionins resulted as the most active peptides tested until now. They collapsed ionic and pH gradients across the parasite plasma membrane together with a rapid depletion of intracellular ATP without affecting mitochondrial potential. Hence the lethal effect of thionins was mostly associated to permeabilization of the plasma membrane leading to an immediate death of the parasite. The present work is the first evidence for leishmanicidal activity in plant peptides. Future prospects for their development as new antiparasite agents on human diseases are considere

Identification of a homolog of Arabidopsis DSP4 (SEX4) in chestnut: its induction and accumulation in stem amyloplasts during winter or in response to the cold_

Oligosaccharide synthesis is an important cryoprotection strategy used by woody plants during winter dormancy. At the onset of autumn, starch stored in the stem and buds is broken down in response to the shorter days and lower temperatures resulting in the buildup of oligosaccharides. Given that the enzyme DSP4 is necessary for diurnal starch degradation in Arabidopsis leaves, this study was designed to address the role of DSP4 in this seasonal process in Castanea sativa Mill. The expression pattern of the CsDSP4 gene in cells of the chestnut stem was found to parallel starch catabolism. In this organ, DSP4 protein levels started to rise at the start of autumn and elevated levels persisted until the onset of spring. In addition, exposure of chestnut plantlets to 4 °C induced the expression of the CsDSP4 gene. In dormant trees or cold-stressed plantlets, the CsDSP4 protein was immunolocalized both in the amyloplast stroma and nucleus of stem cells, whereas in the conditions of vegetative growth, immunofluorescence was only detected in the nucleus. The studies indicate a potential role for DSP4 in starch degradation and cold acclimation following low temperature exposure during activity–dormancy transition

An architecture for virtual labs in engineering education

This paper describes the preliminary results of an educational innovation project in which virtual world technologies have been used to build up a set of virtual laboratories oriented to engineering studies. Focusing on the architecture of a biotechnology laboratory created in this project, we describe how this architecture will also be adopted in other labs under construction, so that these labs can also take advantage of the same educational benefits. Instead of relying on a commercial software solution, these labs have been created with an open source software infrastructure named OpenSim. The limitations found in OpenSim and the solutions that have been provided to overcome these limitations are shown

Antifungal Effect of Essential Oils

Essential oils are employed in agriculture, medicine and food industries among others, due to their antimicrobial, antiviral, insecticidal and antifungal properties. In this chapter, we will focus on the control of fungal plant pathogens with essential oils. Fungal diseases in agricultural crops and forestry alter the physiology of plants, disrupting their normal functioning, reducing their yield and sometimes causing their death. Recent studies show antifungal effects of many essential oils against plant pathogenic fungi, which make them candidates for the development of new fungicidal agents. This chapter presents a review of the most recent advances in this area, as well as the future trends in this field

ATL9, a RING Zinc Finger Protein with E3 Ubiquitin Ligase Activity Implicated in Chitin- and NADPH Oxidase-Mediated Defense Responses

Pathogen associated molecular patterns (PAMPs) are signals detected by plants that activate basal defenses. One of these PAMPs is chitin, a carbohydrate present in the cell walls of fungi and in insect exoskeletons. Previous work has shown that chitin treatment of Arabidopsis thaliana induced defense-related genes in the absence of a pathogen and that the response was independent of the salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) signaling pathways. One of these genes is ATL9 ( = ATL2G), which encodes a RING zinc-finger like protein. In the current work we demonstrate that ATL9 has E3 ubiquitin ligase activity and is localized to the endoplasmic reticulum. The expression pattern of ATL9 is positively correlated with basal defense responses against Golovinomyces cichoracearum, a biotrophic fungal pathogen. The basal levels of expression and the induction of ATL9 by chitin, in wild type plants, depends on the activity of NADPH oxidases suggesting that chitin-mediated defense response is NADPH oxidase dependent. Although ATL9 expression is not induced by treatment with known defense hormones (SA, JA or ET), full expression in response to chitin is compromised slightly in mutants where ET- or SA-dependent signaling is suppressed. Microarray analysis of the atl9 mutant revealed candidate genes that appear to act downstream of ATL9 in chitin-mediated defenses. These results hint at the complexity of chitin-mediated signaling and the potential interplay between elicitor-mediated signaling, signaling via known defense pathways and the oxidative burst

eIF2α Phosphorylation by GCN2 Is Induced in the Presence of Chitin and Plays an Important Role in Plant Defense against B. cinerea Infection

11 Pág.Translation plays an important role in plant adaptation to different abiotic and biotic stresses; however, the mechanisms involved in translational regulation during each specific response and their effect in translation are poorly understood in plants. In this work, we show that GCN2 promotes eIF2α phosphorylation upon contact with Botrytis cinerea spores, and that this phosphorylation is required for the proper establishment of plant defense against the fungus. In fact, independent gcn2 mutants display an enhanced susceptibility to B. cinerea infection, which is highlighted by an increased cell death and reduced expression of ethylene- and jasmonic-related genes in the gcn2 mutants. eIF2α phosphorylation is not only triggered in the presence of the fungus, but interestingly, is also achieved in the sole presence of the microbe-associated molecular pattern (MAMP) chitin. Moreover, analysis of de novo protein synthesis by 35SMet-35SCys incorporation indicates that chitin treatment promotes a global inhibition of translation. Taken together, these results suggest that eIF2α phosphorylation by GCN2 is promoted in the presence of chitin and plays an important role in plant defense against B. cinerea infection.This research has received funding from the grants: S2013-ABI2734 from CAM, RTI2018-095946-B100 from MICIU and “Severo Ochoa Programme for Centres of Excellence in R&D” from the Agencia Estatal de Investigación of Spain (grant SEV-2016-0672Peer reviewe

A Cost-Effective Approach for Procedural Training in Virtual Worlds

Virtual worlds are one of the most promising and interesting lines of research and development in e-learning. Also, the recent maturity of 3D virtual world platforms like Second Life or OpenSimulator has made it possible to deploy such systems at a low cost in schools, colleges or companies. Therefore, these virtual world platforms have enabled the development of cost-effective virtual laboratories. However, there are few empirical studies to support the educational value of Virtual Worlds for Procedural Training (VWPT), especially when they are equipped with automatic tutors. In this paper we present an empirical study that provides evidence in favor of the educational value of virtual worlds. To be precise, we describe the evaluation of a biotechnology VWPT implemented on top of OpenSimulator. We have implemented an automatic tutor within this virtual laboratory in order to supervise and guide students during task practice. This tutor is configurable and can be reused in different VWPTs. This facilitates the development of VWPTs. This virtual laboratory has been evaluated by domain experts (university professors) and students over a three-year period as part of a university course. The analysis of this evaluation has shown good results for usability, user satisfaction and perceived educational utility. It has also served to demonstrate that the virtual laboratory is resilient and reliable. This supports the applied technical approach

A cost-effective approach for procedural training in virtual worlds

Virtual worlds are one of the most promising and interesting lines of research and development in e-learning. Also, the recent maturity of 3D virtual world platforms like Second Life or OpenSimulator has made it possible to deploy such systems at a low cost in schools, colleges or companies. Therefore, these virtual world platforms have enabled the development of cost-effective virtual laboratories. However, there are few empirical studies to support the educational value of Virtual Worlds for Procedural Training (VWPT), especially when they are equipped with automatic tutors. In this paper we present an empirical study that provides evidence in favor of the educational value of virtual worlds. To be precise, we describe the evaluation of a biotechnology VWPT implemented on top of OpenSimulator. We have implemented an automatic tutor within this virtual laboratory in order to supervise and guide students during task practice. This tutor is configurable and can be reused in different VWPTs. This facilitates the development of VWPTs. This virtual laboratory has been evaluated by domain experts (university professors) and students over a three-year period as part of a university course. The analysis of this evaluation has shown good results for usability, user satisfaction and perceived educational utility. It has also served to demonstrate that the virtual laboratory is resilient and reliable. This supports the applied technical approach

Short-Chain Chitin Oligomers: Promoters of Plant Growth

Chitin is the second most abundant biopolymer in nature after cellulose, and it forms an integral part of insect exoskeletons, crustacean shells, krill and the cell walls of fungal spores, where it is present as a high-molecular-weight molecule. In this study, we showed that a chitin oligosaccharide of lower molecular weight (tetramer) induced genes in Arabidopsis that are principally related to vegetative growth, development and carbon and nitrogen metabolism. Based on plant responses to this chitin tetramer, a low-molecular-weight chitin mix (CHL) enriched to 92% with dimers (2mer), trimers (3mer) and tetramers (4mer) was produced for potential use in biotechnological processes. Compared with untreated plants, CHL-treated plants had increased in vitro fresh weight (10%), radicle length (25%) and total carbon and nitrogen content (6% and 8%, respectively). Our data show that low-molecular-weight forms of chitin might play a role in nature as bio-stimulators of plant growth, and they are also a known direct source of carbon and nitrogen for soil biomass. The biochemical properties of the CHL mix might make it useful as a non-contaminating bio-stimulant of plant growth and a soil restorer for greenhouses and fields.Funding was provided in part by grants to Shauna Somerville from the Carnegie Institution of Science and the National Science Foundation, USA (#0114783). Alexander J. Winkler was funded by the Erasmus Program at Universidad Politécnica de Madrid (UPM). We acknowledge the kind contributions, at different stages of this project, of Fernando García Arenal, Pablo González Melendi and Mark Wilkinson from CBGP (UPM-INIA), Luis Díaz Balteiro and Carlos Calderón from MONTES, Carmen Muñoz from E.T.S.I. Forestales (UPM), Norma García from UPM and Elisabeth Magel from Hamburg UniversityWe acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)