La traducción al latín de algunos términos griegos y su repercusión en los comentarios a los "Aphthonii Progymnasmata"

En este trabajo hemos examinado comentarios a la traducción al latín del ejercicio de la Fábula de los Progymnasmata de Aftonio para ver cómo afecta la traducción de algunos términos al comentario. Dado que, al traducir de una lengua a otra, difícilmente hay correspondencia exacta, el traductor opta por la solución que estima más adecuada, primando ciertos matices sobre otros y, con frecuencia, llega, incluso, a dotar al término de acepciones en la lengua meta que no existían en la lengua origen. La elección realizada no parece obedecer a otra razón que a preferencias del traductor, pero tiene consecuencias e influye en los comentaristas. Por otra parte, la existencia de un término acuñado no impide que tanto los traductores como los escoliastas creen otros nuevos, tal vez por deseo de mostrar originalidad. Finalmente, la traducción tiene una doble vertiente: de un lado, influye en el entendimiento del concepto y en el comentario, y, de otro, refleja la concepción que de la realidad tiene el traductor.

Research into crown rot and wilt diseases of strawberries in Queensland

Plant losses due to fungal diseases in strawberry (Fragaria × ananassa Duch.) can potentially cause total loss of production. Three fungal pathogens, Fusarium oxysporum f. sp. fragariae, Colletotrichum gloeosporioides and Macrophomina phaseolina, cause similar crown rot and wilt symptoms in strawberries in Queensland. Since the withdrawal of methyl bromide in 2005, no effective chemical control of any of the three pathogens has been available. This study aims at identifying sources of plant genetic resistance that can be used in the breeding program to develop resistant cultivars for use as part of an integrated disease management plan in commercial strawberry production. Results from glasshouse pathogenicity and screening trials on the three pathogens showed that when breeding for resistance against a pathogen, resistance to other pathogens also needs to be considered, e.g., cultivar 'Festival' is resistant to F. oxysporum f. sp. fragariae, but is highly susceptible to C. gloeosporioides. The cultivars 'Earlisweet', 'Kabarla' and 'Phenomenal', two seedling clones and four DAFF breeding lines were resistant to C. gloeosporioides. Cultivar 'Suncoast Delight' showed the most promising level of resistance to M. phaseolina. These cultivars, breeding lines and seedling selections have been made available for incorporation into the crossing program to support the Queensland strawberry breeding program.

Aislamiento, producción y evaluación de la patogenicidad de cepas de Hirsutella citriformis Speare para el control de Diaphorina citri Kuwayama, vector de la enfermedad Huanglongbing de los cítricos

La industria citrícola es una de las más importantes industrias con las que cuenta el país y en los últimos años se encuentra amenazada por una plaga que está ocasionando estragos en todas las áreas citrícolas en México, el Huanglongbing o greening la cual es transmitida por el psílido asiático de los cítricos, Diaphorina citri Kuwayama, insecto que ocasiona daño en las plantas al alimentarse de los brotes tiernos y que además es el vector de la bacteria Candidatus Liberibacter asiaticus para la cual no hay cura y por lo que es necesario controlar al insecto que la transmite. Por lo que el presente trabajo consistió en aislar hongos de D. citri micosados, identificarlos en base a sus características morfométricas y usando técnicas moleculares, cultivarlos en diferentes medios de cultivo comerciales de agar para seleccionar aquel en el cual crecen y conidian mejor, se determinó también el tipo de exudados producidos por Hirsutella citriformis en los medios de agar, se cultivaron en dos diferentes medios de cultivo líquido y un sustrato vegetal para obtener mayor cantidad de conidios; también se realizaron bioensayos de laboratorio para determinar la virulencia de las cepas y seleccionar aquellas que pudieran controlar mejor al insecto; se evaluó la patogenicidad que pudieran presentar sobre insectos depredadores de D. citri, y con los resultados obtenidos se seleccionó las cepas que presentaron mayor patogenicidad sobre el insecto vector del HLB para evaluar su actividad sobre el mismo en bioensayo de campo. Se aislaron cinco cepas de insectos micosados provenientes de diferentes regiones citrícolas, se trabajó con ellos además de tres cepas con las cuales ya contaba el INIFAP de General Terán de Nuevo León. Se identificaron morfométrica y molecularmente como Hirsutella citriformis Speare. Los medio comerciales de cultivo en los cuales crecen y presentan mejor conidiación son los medios agar papa dextrosa enriquecidos con extracto de levadura al 0.5 y 1 % en los cuales se obtuvo un crecimiento radial de 3.2 a 3.8 cm para las cepas IB-Hir-2 e INIFAP-Hir-1 respectivamente, a los 34 días de cultivo a 25 ± 1 °C. La conidiación obtenida para las ocho cepas no correspondió al crecimiento radial, pero si concordó en presentarse en los medios enriquecidos con extracto de levadura, los valores variaron desde 1.22 x 10⁶ a 2.79 x 10⁷ para las cepas 2 INIFAP-Hir-2 en agar papa dextrosa e IB-Hir-2 en agar papa dextrosa con extracto de levadura al 1% respectivamente. En medios líquidos la mayor producción de blastosporas obtenida fue 4.3 x 108 blastosporas /ml a los 9 días en el medio de casaminoácidos para la cepa INIFAP-Hir-1, y en caldo papa dextrosa la mayor producción la presentó a los 11 días la cepa IB-Hir-2 (7.7 x 107 blastosporas/ml). La mayor producción de conidios en el sustrato vegetal (arroz) se obtuvo a los 14 días por la cepa INIFAP-Hir-4 (1.97 x 107 conidios/gr). Se analizaron los dos tipos de exudados observados en las cepas usando los métodos de Bradford para proteínas y el del Fenol Sulfúrico para carbohidratos y con estos métodos se determinó que todas las cepas producen ambos tipos de compuestos, además de que las proteínas son los exudados amarillo claro y oscuro, mientras que los carbohidratos corresponden a las gotas cristalinas producidas por las cepas en los diferentes medios de agar. En los diferentes bioensayos de laboratorio las cepas presentaron mayor mortalidad cuando se inoculó por contacto, donde las cepas INIFAP-Hir-1, INIFAP-Hir-2, IB-Hir-1 e IB-Hir-2 mostraron los mayores porcientos de mortalidad media. Al evaluar la patogenicidad de cuatro cepas sobre dos depredadores de D. citri, los resultados fueron similares para tratamientos y testigo y no se presentó micosamiento en los insectos muertos. Bajo condiciones de laboratorio la CL50 y CL90 obtenidas para el aislado INIFAP-Hir-1 fueron, 34 x 105 y 26.7 x 107 respectivamente. En el bioensayo de campo se usaron las cepas INIFAP.Hir-2, INIFAP.Hir-4, IB-Hir-1 e IB-Hir-2 y el mayor porciento de mortalidad obtenida fue 51.049 y el menor 35.7 para las cepas INIFAP-Hir-4 e IB-Hir-1 respectivamente, mientras que el testigo con adherente mostro 6.059 y en el testigo absoluto 4.84 % de mortalidad promedio. Además logramos aislar la cepa que los micosaba de 20 insectos colectados en diferentes puntos de muestreo, identificando en base a sus características morfológicas de crecimiento colonial a tres de las cepas evaluadas y a la cepa nativa de Martínez de la Torre.

STRUCTURE AND FUNCTION OF THE GROUP III CHAPERONINS, A UNIQUE CLADE OF PROTEIN FOLDING NANOMACHINES

The survival and descent of cells is universally dependent on maintaining their proteins in a properly folded condition. It is widely accepted that the information for the folding of the nascent polypeptide chain into a native protein is encrypted in the amino acid sequence, and the Nobel Laureate Christian Anfinsen was the first to demonstrate that a protein could spontaneously refold after complete unfolding. However, it became clear that the observed folding rates for many proteins were much slower than rates estimated in vivo. This led to the recognition of required protein-protein interactions that promote proper folding. A unique group of proteins, the molecular chaperones, are responsible for maintaining protein homeostasis during normal growth as well as stress conditions. Chaperonins (CPNs) are ubiquitous and essential chaperones. They form ATP-dependent, hollow complexes that encapsulate polypeptides in two back-to-back stacked multisubunit rings, facilitating protein folding through highly cooperative allosteric articulation. CPNs are usually classified into Group I and Group II. Here, I report the characterization of a novel CPN belonging to a third Group, recently discovered in bacteria. Group III CPNs have close phylogenetic association to the Group II CPNs found in Archaea and Eukarya, and may be a relic of the Last Common Ancestor of the CPN family. The gene encoding the Group III CPN from Carboxydothermus hydrogenoformans and Candidatus Desulforudis audaxviator was cloned in E. coli and overexpressed in order to both characterize the protein and to demonstrate its ability to function as an ATPase chaperone. The opening and closing cycle of the Chy chaperonin was examined via site-directed mutations affecting the ATP binding site at R155. To relate the mutational analysis to the structure of the CPN, the crystal structure of both the AMP-PNP (an ATP analogue) and ADP bound forms were obtained in collaboration with Sun-Shin Cha in Seoul, South Korea. The ADP and ATP binding site substitutions resulted in frozen forms of the structures in open and closed conformations. From this, mutants were designed to validate hypotheses regarding key ATP interacting sites as well as important stabilizing interactions, and to observe the physical properties of the resulting complexes by calorimetry.

Doenças em plantios jovens de eucalipto em sistemas agroflorestais no Acre.

O uso de sistemas agrossilvipastoris com plantio de eucalipto tem se tornado bastante importante no Acre. Com o aumento dos cultivos de eucalipto no Acre, tem ocorrido o ataque de patógenos no campo principalmente durante os estágios iniciais da cultura. Conhecer as principais doenças que afetam os plantios de eucalipto é fundamental para o sucesso dos sistemas agrossilvipastoris que empregam esta espécie. Assim este trabalho teve como objetivo relatar as principais doenças em plantios de eucalipto no Acre associados a sistemas silvipastoris em implantação. Foram avaliadas três áreas com plantios jovens de eucalipto com diferentes espécies. Nas áreas foram realizadas visitas mensais para detecção de doenças. Plantas com sintomas de doenças foram trazidas ao Laboratório de Fitopatologia da Embrapa Acre para diagnóstico. Em campo avaliou-se a incidência e severidade das doenças. Foram relatadas os seguintes patossistemas: Ralstonia solanacearum - Murcha Bacteriana; Xanthomonas axonopodis - Mancha Foliar Bacteriana do Eucalipto; Puccinia psidii - Ferrugem do Eucalipto; Coniella fragariae ? Mancha de Coniela; e Cylindrocladium spp. ? Mancha de Cylindrocladium.

Uso do R-shiny para execução de modelos matemáticos via web: estudo de caso sobre a dinâmica de propagação do HLB do citros.

RESUMO - O Huanglongbing (HLB ou Greening) é a doença mais importante e destrutiva da citricultura mundial. Presente de forma endêmica nos continentes asiático e africano há várias décadas, essa doença foi constatada no Brasil em 2004, sendo transmitida pelo psilídeo Diaphorina citri e causada por bactérias de floema Candidatus Liberibacter spp. Para auxiliar o estudo da doença, foram desenvolvidos modelos matemáticos para avaliação da propagação do HLB Citros. Este trabalho tem por objetivo a criação de um sistema para execução via web de um destes modelos, permitindo aos profissionais de diversas formações, em especial os das áreas biológicas, que são os especialistas do domínio em estudo, acesso rápido aos resultados fornecidos pelo modelo matemático, eliminando ainda a necessidade de conhecimento prévio em alguma linguagem de programação ou de métodos de resolução de equações diferenciais. O sistema foi completamente implementado em R, tendo sido o pacote deSolve usado para solução do modelo matemático e o framework web Shiny para a interface com usuário, sendo todos open source.

Deciphering the role of plant microbiome on strawberry and raspberry growth, resistance, fruit quality and aroma

Besides their own adaptation strategies, plants might exploit microbial symbionts for overcoming both biotic and abiotic stresses and increase fitness. The current scenario of rapid climate change is demanding more sustainable agricultural management practices. The application of microbe-based products as a valid alternative to synthetic pesticides and fertilizers and their use to overcome stresses exacerbated by climate change, have been reviewed in the first part of this thesis. Berry fruits are widely cultivated and appreciated for their aromatic and nutraceutical properties. This thesis is focused on the role of plant and fruit microbiome on strawberry and raspberry growth, resistance, fruit quality and aroma. A taxonomical and functional description of the microbiome of different organs of three strawberry genotypes was performed both by traditional cultural dependent method and Next Generation Sequencing technique, highlighting a significant role of plant organs and genotype in determining the composition of microbial communities. Additionally, a selection of bacteria native of strawberry plants were isolated and screened for their plant growth promoting abilities and tested under the biotic stress of Xanthomonas fragariae infection and the abiotic stress of induced salinity. The monitoring of biometric parameters allowed the selection of a more restricted panel of bacterial strains, whose beneficial potential was tested in coordinated inoculations, or singularly. Raspberry plant was used for investigating the effect of cultivation method in determining fruit microbiome, and its consequent influence of berry quality and aroma. Interestingly, the cultivation method strongly influenced fruit nutraceutical traits, aroma and epiphytic bacterial biocoenosis. The involvement of the bacterial microbiota in fruit aroma determination was evaluated by performing GC–MS analysis of VOCs occurring in control, sterile and artificially reinoculated berries and by characterizing control and reinoculated berry microbiome. Differently treated berries showed significantly different aromatic profile, confirming the role of bacteria in fruit aroma development.

Essential oils and hydrolates as potential tools for integrated prevention of bacterial diseases in plants

The present work aims to investigate the potential use of natural substances against bacterial plant pathogens. Microdilution tests were therefore carried out in vitro to identify the minimum inhibitory and bactericidal concentrations (MIC and MBC) of several EOs and Hys against selected bacterial pathogens. Commercial products based on a mixture of EOs were in addition assayed with macrodilution experiments against Erwinia amylovora (Ea-causal agent of fire blight). Subsequently, using selected EOs, Hys, and commercial products, ex vivo tests on disease incidence and Ea population dynamics were carried out; the latter experiment was followed by SEM observations. In addition, in vivo resistance induction test was carried out against bacterial leaf of tomato, caused by Xanthomonas vesicatoria (Xv). EOs and Hys showed high bactericidal activity in vitro (MBC <0.1 and <10% for the most active EOs and Hys: Origanum compactum and Thymus vulgaris EOs and Citrus aurantium var. amara Hy, respectively), but they were not effective ex vivo, while resulted very active when used in vivo as resistance inducers in the tomato-Xv pathosystem (relative protection >40%). Differently, commercial products resulted active in all tests, but not as resistance inducers against Xv. An open field trial with commercial products was carried out on strawberry plants naturally infected with Xanthomonas fragariae; the results showed discrete relative protection, concerning that provided by the conventional products based on copper; mostly, the disease severity reduction on those plants treated with EOs commercial products was significant when disease severity resulted high. The papers already published described in the present work investigate (1)the activity of Hys in comparison to EOs with respect to their active volatile content; (2) the potential use of EOs and Hys in cultural heritage; for the restoration of paintings; (3) the induction of resistance caused by plasma-activated water-based root treatments.