Comprehensive Time-Series Analysis of the Gene Expression Profile in a Susceptible Cultivar of Tree Tomato (Solanum betaceum) During the Infection of Phytophthora betacei.

Solanum betaceum is a tree from the Andean region bearing edible fruits, considered an exotic export. Although there has been renewed interest in its commercialization, sustainability, and disease management have been limiting factors. Phytophthora betacei is a recently described species that causes late blight in S. betaceum. There is no general study of the response of S. betaceum, particularly, in the changes in expression of pathogenesis-related genes. In this manuscript we present a comprehensive RNA-seq time-series study of the plant response to the infection of P. betacei. Following six time points of infection, the differentially expressed genes (DEGs) involved in the defense by the plant were contextualized in a sequential manner. We documented 5,628 DEGs across all time-points. From 6 to 24 h post-inoculation, we highlighted DEGs involved in the recognition of the pathogen by the likely activation of pattern-triggered immunity (PTI) genes. We also describe the possible effect of the pathogen effectors in the host during the effector-triggered response. Finally, we reveal genes related to the susceptible outcome of the interaction caused by the onset of necrotrophy and the sharp transcriptional changes as a response to the pathogen. This is the first report of the transcriptome of the tree tomato in response to the newly described pathogen P. betacei.

The type VI secretion system of Xanthomonas phaseoli pv. manihotis is involved in virulence and in vitro motility.

BACKGROUND: The type VI protein secretion system (T6SS) is important in diverse cellular processes in Gram-negative bacteria, including interactions with other bacteria and with eukaryotic hosts. In this study we analyze the evolution of the T6SS in the genus Xanthomonas and evaluate its importance of the T6SS for virulence and in vitro motility in Xanthomonas phaseoli pv. manihotis (Xpm), the causal agent of bacterial blight in cassava (Manihot esculenta). We delineate the organization of the T6SS gene clusters in Xanthomonas and then characterize proteins of this secretion system in Xpm strain CIO151. RESULTS: We describe the presence of three different clusters in the genus Xanthomonas that vary in their organization and degree of synteny between species. Using a gene knockout strategy, we also found that vgrG and hcp are required for maximal aggressiveness of Xpm on cassava plants while clpV is important for both motility and maximal aggressiveness. CONCLUSION: We characterized the T6SS in 15 different strains in Xanthomonas and our phylogenetic analyses suggest that the T6SS might have been acquired by a very ancient event of horizontal gene transfer and maintained through evolution, hinting at their importance for the adaptation of Xanthomonas to their hosts. Finally, we demonstrated that the T6SS of Xpm is functional, and significantly contributes to virulence and motility. This is the first experimental study that demonstrates the role of the T6SS in the Xpm-cassava interaction and the T6SS organization in the genus Xanthomonas.

Genome-Scale Metabolic Model of Xanthomonas phaseoli pv. manihotis: An Approach to Elucidate Pathogenicity at the Metabolic Level.

Xanthomonas phaseoli pv. manihotis (Xpm) is the causal agent of cassava bacterial blight, the most important bacterial disease in this crop. There is a paucity of knowledge about the metabolism of Xanthomonas and its relevance in the pathogenic process, with the exception of the elucidation of the xanthan biosynthesis route. Here we report the reconstruction of the genome-scale model of Xpm metabolism and the insights it provides into plant-pathogen interactions. The model, iXpm1556, displayed 1,556 reactions, 1,527 compounds, and 890 genes. Metabolic maps of central amino acid and carbohydrate metabolism, as well as xanthan biosynthesis of Xpm, were reconstructed using Escher (https://escher.github.io/) to guide the curation process and for further analyses. The model was constrained using the RNA-seq data of a mutant of Xpm for quorum sensing (QS), and these data were used to construct context-specific models (CSMs) of the metabolism of the two strains (wild type and QS mutant). The CSMs and flux balance analysis were used to get insights into pathogenicity, xanthan biosynthesis, and QS mechanisms. Between the CSMs, 653 reactions were shared; unique reactions belong to purine, pyrimidine, and amino acid metabolism. Alternative objective functions were used to demonstrate a trade-off between xanthan biosynthesis and growth and the re-allocation of resources in the process of biosynthesis. Important features altered by QS included carbohydrate metabolism, NAD(P)+ balance, and fatty acid elongation. In this work, we modeled the xanthan biosynthesis and the QS process and their impact on the metabolism of the bacterium. This model will be useful for researchers studying host-pathogen interactions and will provide insights into the mechanisms of infection used by this and other Xanthomonas species.

A Genome-Scale Metabolic Reconstruction of Phytophthora infestans With the Integration of Transcriptional Data Reveals the Key Metabolic Patterns Involved in the Interaction of Its Host.

Phytophthora infestans, the causal agent of late blight disease, affects potatoes and tomatoes worldwide. This plant pathogen has a hemibiotrophic lifestyle, having an initial biotrophic infection phase during which the pathogen spreads within the host tissue, followed by a necrotrophic phase in which host cell death is induced. Although increasing information is available on the molecular mechanisms, underlying the distinct phases of the hemibiotrophic lifestyle, studies that consider the entire metabolic processes in the pathogen while undergoing the biotrophic, transition to necrotrophic, and necrotrophic phases have not been conducted. In this study, the genome-scale metabolic reconstruction of P. infestans was achieved. Subsequently, transcriptional data (microarrays, RNA-seq) was integrated into the metabolic reconstruction to obtain context-specific (metabolic) models (CSMs) of the infection process, using constraint-based reconstruction and analysis. The goal was to identify specific metabolic markers for distinct stages of the pathogen's life cycle. Results indicate that the overall metabolism show significant changes during infection. The most significant changes in metabolism were observed at the latest time points of infection. Metabolic activity associated with purine, pyrimidine, fatty acid, fructose and mannose, arginine, glycine, serine, and threonine amino acids appeared to be the most important metabolisms of the pathogen during the course of the infection, showing high number of reactions associated with them and expression switches at important stages of the life cycle. This study provides a framework for future throughput studies of the metabolic changes during the hemibiotrophic life cycle of this important plant pathogen.

Network Analyses in Plant Pathogens.

Even in the age of big data in Biology, studying the connections between the biological processes and the molecular mechanisms behind them is a challenging task. Systems biology arose as a transversal discipline between biology, chemistry, computer science, mathematics, and physics to facilitate the elucidation of such connections. A scenario, where the application of systems biology constitutes a very powerful tool, is the study of interactions between hosts and pathogens using network approaches. Interactions between pathogenic bacteria and their hosts, both in agricultural and human health contexts are of great interest to researchers worldwide. Large amounts of data have been generated in the last few years within this area of research. However, studies have been relatively limited to simple interactions. This has left great amounts of data that remain to be utilized. Here, we review the main techniques in network analysis and their complementary experimental assays used to investigate bacterial-plant interactions. Other host-pathogen interactions are presented in those cases where few or no examples of plant pathogens exist. Furthermore, we present key results that have been obtained with these techniques and how these can help in the design of new strategies to control bacterial pathogens. The review comprises metabolic simulation, protein-protein interactions, regulatory control of gene expression, host-pathogen modeling, and genome evolution in bacteria. The aim of this review is to offer scientists working on plant-pathogen interactions basic concepts around network biology, as well as an array of techniques that will be useful for a better and more complete interpretation of their data.

Evaluación del método ELISA de punto para el diagnóstico de la cisticercosis humana y para estimar valores de prevalencia en una región endémica en Colombia / Evaluation of the ELISA method for diagnosis of human cysticercosis in an endemic region

Introducción . La cisticercosis continúa siendo un problema de salud pública a nivel mundial. El diagnóstico de esta enfermedad se hace por medio de la detección de anticuerpos específicos y de técnicas de imaginología. Objetivo. Evaluar la ELISA de punto, método inmunoenzimático, en la detección de anticuerpos contra Taenia solium para ser usado tanto en pacientes con neurocisticercosis como en poblaciones donde es endémica. Materiales y métodos . Se utilizaron 45 muestras de suero, 41 de plasma y 23 de líquido cefalorraquídeo de pacientes con cisticercosis confirmada según criterios clínicos, quirúrgicos, imaginológicos y de laboratorio. Además, se estudiaron 37 muestras de suero, 64 de plasma y 17 de líquido cefalorraquídeo de personas que no presentaban cisticercosis y que no tenían antecedentes epidemiológicos de teniosis-cisticercosis. Se evaluaron también 43 muestras de suero de personas con parasitosis diferentes a cisticercosis y 663 muestras de suero de unestudio de seroprevalencia de cisticercosis en una comunidad rural colombiana. Las muestras se procesaron tanto por inmunoelectrotransferencia como por la ELISA de punto. La inmunoelectrotransferencia se utilizó como prueba de oro para establecer la sensibilidad y laespecificidad de la ELISA de punto. Se analizaron 933 muestras. Resultados. Con las 109 muestras de los individuos afectados por cisticercosis y las 118muestras de controles sanos se hicieron los análisis estadísticos de validación de la prueba diagnóstica y se obtuvo para la ELISA de punto una sensibilidad total de 80,7 por ciento(IC95 por ciento: 80,2 por ciento a 81,2 por ciento) y una especificidad de 92,4 por ciento(IC95 por ciento: 91,9 por ciento a 92,8 por ciento). La ELISA de punto realizado con suero, plasma y líquido cefalorraquídeo tuvo una sensibilidad de 91,1 por ciento, 85,4 por ciento y 52,12 por ciento, respectivamente. La misma prueba evaluada en suero, plasma y líquido cefalorraquídeo tuvo una especificidad de 100 por ciento, 85,9 por ciento y 100 por ciento, respectivamente. Las 43 muestras de personas con otras parasitosis diferentes de cisticercosis fueron negativas para ambas pruebas.Cuando la ELISA de punto se utilizó para el diagnóstico de la cisticercosis en una población endémica colombiana en la que 1,81 por ciento(12/663) de las personas presentó anticuerpos para T. solium por...

[Evaluation of the ELISA method for diagnosis of human cysticercosis in an endemic region]. / Evaluación del método ELISA de punto para el diagnóstico de la cisticercosis humana y para estimar valores de prevalencia en una región endémica en Colombia.

INTRODUCTION: Cysticercosis is a worldwide public health problem. Currently it is diagnosed by detection of specific antibodies or by imaging techniques. OBJECTIVE: To evaluate an alternative diagnostic tool, a simple antibody detection assay, called Dot ELISA, for immunological diagnosis of patients with neurocysticercosis as well as for endemic population screening. MATERIALS AND METHODS: The test was applied to cysticercosis patients, as well as to healthy controls and individuals with other parasitic infections. A total of 45 serum, 41 plasma and 23 cerebrospinal fluid samples were obtained from patients meeting clinical, surgical, imaging and laboratory criteria for cysticercosis. Samples were processed by enzyme-linked immune-electro-transfer blot assay and by Dot ELISA. Controls included 37 serum, 64 plasma and 17 cerebrospinal fluid samples from healthy individuals without epidemiological history for taeniosis-cysticercosis. Similarly, 43 plasma samples from patients with parasitic infections different from cysticercosis and 663 samples from population survey for cysticercosis were also evaluated. RESULTS: A total of 933 samples were analyzed. In samples from cysticercosis patients and healthy control individuals, the Dot ELISA test showed an overall sensitivity of 80.7% (CI 95% = 80.2%-81.2%) and a specificity of 92.4% (CI 95% = 91.9%-92.8%). The Dot ELISA performed in serum had a sensitivity of 91.1%, in plasma 85.4%, and in cerebrospinal fluid 52.2%. Similarly, the same test performed in serum, plasma and cerebrospinal fluid, had a specificity of 100%, 85.9% and 100% respectively. The Dot ELISA was applied as a screening test for the diagnosis of cysticercosis in an endemic population in which 1.8% (12/663) of individuals had T. solium antibodies detected by Enzyme-linked immune-electro-transfer blot assay and showed a sensitivity of 58.3% (CI 95% = 54.0-62.7) and a specificity of 100% (CI 95% = 99.9-100.0) with a positive predictive value of 100% and a negative predictive value of 99.2%. All 43 samples from patients with parasitic infections different from cysticercosis were negative for both tests. CONCLUSIONS: These results indicated that Dot ELISA is a promising tool for the diagnosis of cysticercosis as a screening test, as well as for field epidemiological studies.

Efectos de la desparasitación comunitaria en la población Infantil del área Urbana de Apartadó, Colombia / Mass parasitosis control effects in the infantile population in the urban area of Apartado, Colombia

Se realizó un programa de desparasitación comunitaria para helmintos transmitidos por el suelo, en el Municipio de Apartadó, Departamento de Antioquia, Colombia, durante los años de 1996 al 1998. La población tratada fue en promedio de 8.386 niños de 2 a 10 años del área urbana del Municipio. De acuerdo a la intensidad parasitaria, revelada por el recuento de huevos de helmintos en materias fecales, por el método de Kato-Kats, se clasificaron en 3 grupos. Como parasitismo severo, moderado o leve. El antihelmíntico usado fue mebendazol en suspensión a dosis única de 30 ml, equivalente a 600 mg, para un total de cuatro administraciones con intervalos de seis meses. Paralelamente con este programa terapéutico se hicieron actividades de educación y promoción de la salud...

Current consensus guidelines for treatment of neurocysticercosis.

Taenia solium neurocysticercosis is a common cause of epileptic seizures and other neurological morbidity in most developing countries. It is also an increasingly common diagnosis in industrialized countries because of immigration from areas where it is endemic. Its clinical manifestations are highly variable and depend on the number, stage, and size of the lesions and the host's immune response. In part due to this variability, major discrepancies exist in the treatment of neurocysticercosis. A panel of experts in taeniasis/cysticercosis discussed the evidence on treatment of neurocysticercosis for each clinical presentation, and we present the panel's consensus and areas of disagreement. Overall, four general recommendations were made: (i) individualize therapeutic decisions, including whether to use antiparasitic drugs, based on the number, location, and viability of the parasites within the nervous system; (ii) actively manage growing cysticerci either with antiparasitic drugs or surgical excision; (iii) prioritize the management of intracranial hypertension secondary to neurocysticercosis before considering any other form of therapy; and (iv) manage seizures as done for seizures due to other causes of secondary seizures (remote symptomatic seizures) because they are due to an organic focus that has been present for a long time.

Infección por Cyclospora sp. en tres pacientes inmunocompetentes / Cyclospora sp. infection in tree immunocompetent patients

Se presentan tres casos de pacientes inmunocompetentes con síndrome diarreico que consultaron al Instituto Colombiano de Medicina Tropical en Medellín. El único agente patógeno aislado de sus muestras fecales fue cyclospora sp. Una paciente fue tratada con un medicamento antiparasitario experimental, la nitazoxanida, y los otros dos pacientes con trimetropin-sulfametoxazole, todos con buenos resultados. Se presenta un revisión de algunos aspectos de la enfermedad y se recomienda que, en casos de diarrea prolongada, se disponga de un protocolo completo para estudio de parásitos en materia fecal, además de capacitar muy bien al personal de salud que lee los coprológicos para establecer un diagnóstico diferencial entre el grupo de coccidias

Criptospiridiasis respiratoria en un paciente con SIDA

Se presenta un paciente colombiano, adulto de sexo masculino, con diagnóstico de SIDA, que presentó enfermedad entérica y pulmonar causada por Cryptosporidium. Se discute diferentes aspectos relacionados con la criptosporidiosis humana y se comparan con lo informado en la literatura médica

Programa Centroamericano de educación y control de helmintiasis intestinales

El Programa Centroamericano de Educación Sanitaria y control de Helmintiasis Intestinales representa un esfuerzo para disminuir la morbi-mortalidad causada por el parasitismo intestinal, por medio de la coordinación efectiva entre gobiernos, agencias internacionales, organismos privados voluntarios y la empresa privada. El programa se desarrollará en el marco de la estrategia de Atención Primaria en Salud y se constituirá en un aporte a la atención de necesidades prioritarias en salud de la Subregión, en apoyo a la iniciativa "Salud, Puente para la Paz". El Programa se ejecutará por medio de las acciones y estructuras existentes en los países, con lo cual se contribuye al fortalecimiento de los sistemas locales de salud y a la optimización d ela utilización de los recursos. El programa está orientado y auspiciado por una Comisión Ccientífica independente. El Programa contiene tres componentes indispensables: - Los estudios para medir su efectividad. La desparasitación periódica. La educación sanitaria sistematizada y actualizada tendrá una duración mínima de cinco años

Tratamiento de amebiasis intestinal con Secnidazol. II. Estudio doble ciego en portadores asintomáticos

Se estudiaron 100 portadores asintomáticos de Entoameba histolytica o de Entameba hartmanni, ameba no patógena que frecuentemente se confunde con la primera. Se dividieron al azar en dos grupos que recibieron secnidazol o placebo en dosis única. El secnidazol se administró, de acuerdo con la edad, a una dosis promedio de 30 mg/kg. Se hicieron controles parasitológicos post-tratamiento a la una y dos semanas y se encontró que hubo negativización en 56 por ciento de los que recibieron antiamibiano y solo en 24 por ciento de los que recibieron placebo. La tolerancia fue buena, no hubo reacciones tóxicas.

Sepsis en ninos menores de 2 anos: Hospital General de Medellin, 1987 / Sepsis in children under 2 years of age: Hospital General de Medellin, 1987

Estudio descriptivo retrospectivo realizado en el Hospital General de Medellin, que permite conocer las caracteristicas de los pacientes menores de dos anos con sepsis, toando como referencia 85 pacientes con esta patologia que consultaron en 1987. Hay predominio del sexo masculino, hallandose la mayoria de los casos entre 0-3 meses de edad. El origen de los pacientes era 91.7% de la ciudad de Medellin, de los cuales el 69.4% eran nacidos en el Hospital General de Medellin. La principal sintomatologia fue dificultad respiratoria y diarrea. La positividad de los hemocultivos fue de un 72%, el germen mas encontrado fue el estafilococo aureus. Se encontro un 83% de los pacientes con hipoglicemia, un 12% con hiperkalemia y un 29% con hipomagnesemia; la trobocitopenia estaba presente en un 12.9%. Los antibioticos mas usados fueron gentamicina, penicilina cristalina, dicloxacilina y amplicilina, duracion promedio de antibioticoterapia y hospitalizacion 16 dias. La letalidad total fue de 41

Tratamiento de amebiasis intestinal sintomatica y asintomatica y giardiasis / Treatment of symptomatic and non symptomatic intestinal amebiasis and giardiasis

El tratamiento de amebiasis intestinal sintomatica con secnidazol en dosis unica de 2 g para mayores de 15 anos y 30 mg/kg para menores de esa edad, produjo curaciones en el 72% de los casos. En portadores asintomaticos de E.histolytica la curacion parasitologica se elevo a 89%, cuando la dosis mencionada se suministro durante tres dias consecutivos. En giardiasis la curacion clinica y parasitologica se obtuvo en 93%, utilizando la dosis unica mencionada inicialmente. La tolerancia al medicamento fue muy buena en los ninos, pues no se observo ningun efecto colateral en los tratados para giardiasis y solo en el 17% de los que recibieron dosis triple como portadores asintomaticos de amebiasis. En 28% de los tratados con dosis unica para amebiasis sintomatica se evidencio alguna intolerancia. Es de anotar que estos ultimos casos fueron pacientes adultos

Tratamiento de las parasitosis intestinales humanas / Treatment of human intestinal parasitoses

Se presenta una revision actualizada sobre las drogas usadas en el tratamiento de las parasitosis intestinales, esencialmente en aquellas que se encuentran en Colombia. Inicialmente se mencionan las parasitosis, primero las causadas por helmintos y luego las producidas por protozoos y para cada una de ellas se da el nombre de las drogas utiles. Luego se dedica un parrafo a cada una de las drogas, mencionando lo principal en cuanto a su composicion quimica, absorcion, eliminacion, efectos secundarios, toxicidad, precauciones, utilidad terapeutica y dosificacion. Se publica una amplia lista de referencias que permite ampliar los datos sobre el tema.

Estudio comparativo de los métodos de Kato Katz y de Beaver modificado para el recuento de huevos de helmintos / Comparative study of the Kato Katz method and the modified Beaver technic for parasite egg count

Después de revisar varios trabajos sobre métodos de recuento de huevos de helmintos, analizamos el de Kato Katz y lo comparamos son el método de Beaver modificado. Para este estudio escogimos una comunidad para recuperación de gamines, con una población de 250 estudiantes y 13 profesores, a todos los cuales se les hizo estudio de materia fecal por los dos métodos. El método de Kato Katz detectó más infecciones por Trichuris trichiura, uncinarias y Ascaris Iumbricoides, con diferencia estadíticamente significativa para los dos primeros