Recovery of active pathogenesis-related enzymes from the apoplast of Musa acuminata infected by Mycosphaerella fijiensis

The fungus Mycosphaerella fijiensis causes black Sigatoka (BS) disease, a major pathogen in the banana industry worldwide. Numerous molecular and biochemical studies have been done for the M. fijiensis, Musa acuminata interaction, but this is the first study describing the zymographic behavior of β-1,3-glucanase, chitinase and protease in the apoplast and symplast of healthy, BS-infected but asymptomatic and BS diseased banana leaves. In BS-infected tissues, β-1,3-glucanase enzymatic activity was associated with two polypeptides with retention index (Ri) values of 0.43 and 0.56. These were more notable in the apoplast than in the symplast. Chitinase activity in BS-infected tissue in both the apoplast and symplast was mainly associated with a single polypeptide (Ri = 0.89). Both β-1,3-glucanase and chitinase activities were apparently more intense in BS-infected leaves than in healthy leaves. Protease activity was associated with two polypeptides (Ri = 0.04 and 0.14). In both the apoplast and symplast, the Ri 0.04 polypeptide increased in intensity with disease progression, whereas Ri 0.14 polypeptide intensity decreased. Overall protease activity intensity was higher in the symplast. Maximum symplast contamination of the apoplast was 2% as estimated by glucose 6-phosphate dehydrogenase activity, a biochemical marker for symplast. Accumulation of pathogenesis-related enzymatic activities in the apoplast of M. acuminata leaf tissue was caused by hostcontrolled enzyme downloading in response to M. fijiensis infection. Clear differences were identified in the electrophoretic profiles of healthy and diseased banana plants. The results further support a putative role of these enzymes in the extracellular defense repertoire of banana and, more importantly, suggest that M. fijiensis possesses a mechanism for suppression and delay of defense response in M. acuminata.Key words: Black Sigatoka, glucose 6-phosphate dehydrogenase, pathogenesis-related (PR) proteins, polyacrylamide gel electrophoresis (PAGE), retention index (Ri), sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE)

Análisis modal comparado entre modelos virtuales 2d y 3d aplicado a un Cube Sat

El siguiente trabajo presenta un análisis modal comparado entre modelos virtuales 2D y 3D, para validar la sistematización de una metodología de análisis completo de Ingeniería Asistida por Computadora, ejemplificada en la aplicación a un modelo de nano satélite tipo Cube Sat. Se detallan los requerimientos de las especificaciones técnicas, condiciones estructurales, cargas, restricciones y frecuencias de vibración, que sufre este satélite al momento de su despegue y durante su órbita. Posteriormente se aplica al Diseño Asistido por Computadora la solicitud del análisis de respuesta dinámica al modelo de su estructura principal simplificada, utilizando el Método de los Elementos Finitos. Las simulaciones incluyen el análisis dinámico de frecuencias naturales y modos de vibración libre. La comparación se lleva a cabo con las herramientas de un Sistema de Ingeniería Basada en el Conocimiento que permiten optimizar la elaboración de diseños mecánicos y reducir tiempos de solución ante nuevos retos de simulación

Modelación hidrológica con el modelo SWAT empleando diferentes distribuciones espaciales del tipo suelo en la cuenca del Río Mixteco

La cuenca del río Mixteco se ubica en el estado de Oaxaca, México y comprende una superficie total de 6 559.20 km2; esta presenta fuerte degradación de sus recursos naturales, derivado principalmente de las acciones antrópicas asociadas a una mala administración de sus recursos naturales. El objetivo de este trabajo fue evaluar el comportamiento del escurrimiento superficial mediante el modelo SWAT (Soil and Water Assessment Tool) en la cuenca del río Mixteco utilizando tanto la distribución espacial de suelo del INEGI (Instituto Nacional de Estadística y Geografía) como la obtenida a través de la técnica de DSM (Mapeo Digital de Suelos). La modelación con INEGI (ModINEGI) correspondió al mapa edafológico de la Serie II escala 1:250,000 y la modelación con DSM (ModDSM) se obtuvo a partir de covariables ambientales. Los indicadores de evaluación del desempeño del modelo SWAT durante la fase de calibración fueron R2 = 0.88 y NSE = 0.87 para ModDSM y R2 = 0.85 y NSE = 0.85 para ModINEGI; sin embargo, durante el periodo de validación, los resultados de ModDSM (R2 = 0.83 y NSE = 0.81) fueron mejores que los de ModINEGI (R2 = 0.83 y NSE = 0.61). Por lo tanto, los resultados indican que la variación espacial de los tipos de suelo obtenida a través de la técnica de DSM, en combinación con la cobertura vegetal y la distribución de las pendientes a nivel cuenca, permiten al modelo SWAT simular de forma adecuada el comportamiento del escurrimiento superficial

The diversity and evolution of pollination systems in large plant clades: Apocynaceae as a case study

Background and Aims Large clades of angiosperms are often characterized by diverse interactions with pollinators, but how these pollination systems are structured phylogenetically and biogeographically is still uncertain for most families. Apocynaceae is a clade of >5300 species with a worldwide distribution. A database representing >10 % of species in the family was used to explore the diversity of pollinators and evolutionary shifts in pollination systems across major clades and regions. Methods The database was compiled from published and unpublished reports. Plants were categorized into broad pollination systems and then subdivided to include bimodal systems. These were mapped against the five major divisions of the family, and against the smaller clades. Finally, pollination systems were mapped onto a phylogenetic reconstruction that included those species for which sequence data are available, and transition rates between pollination systems were calculated. Key Results Most Apocynaceae are insect pollinated with few records of bird pollination. Almost three-quarters of species are pollinated by a single higher taxon (e.g. flies or moths); 7 % have bimodal pollination systems, whilst the remaining approx. 20 % are insect generalists. The less phenotypically specialized flowers of the Rauvolfioids are pollinated by a more restricted set of pollinators than are more complex flowers within the Apocynoids + Periplocoideae + Secamonoideae + Asclepiadoideae (APSA) clade. Certain combinations of bimodal pollination systems are more common than others. Some pollination systems are missing from particular regions, whilst others are over-represented. Conclusions Within Apocynaceae, interactions with pollinators are highly structured both phylogenetically and biogeographically. Variation in transition rates between pollination systems suggest constraints on their evolution, whereas regional differences point to environmental effects such as filtering of certain pollinators from habitats. This is the most extensive analysis of its type so far attempted and gives important insights into the diversity and evolution of pollination systems in large clades

Histopathological alterations in mice under sub-acute treatment with Hintonia latiflora methanolic stem bark extract

The indiscriminate use of herbal products is increasingly growing worldwide; nonetheless consumers are not warned about the potential health risks that these products may cause. Hintonia latiflora (Hl) is a tree native to the American continent belonging to the Rubiaceae family and its stem bark is empirically used mainly to treat diabetes and malaria; supplements containing Hl are sold in America and Europe without medical prescription, thus scientific information regarding its toxicity as a consequence of a regular consumption is needed. In the present study, the histopathological effect of 200 and 1000 mg/kg of Hl methanolic stem bark extract (HlMeOHe) was evaluated in the small bowel, liver, pancreas, kidneys and brain of CD-1 male mice after oral sub-acute treatment for 28 days. No histopathological alterations were observed in the brain of the treated animals; however, mice presented diarrhea from day 2 of treatment with both doses. No histological changes were observed in the tissues collected from the animals treated with 200 mg/kg, except for the liver that depicted periportal hepatitis. Animals treated with the higher dose showed in the liver sections hydropic degeneration, hepatitis and necrosis small bowel sections showed dilated mucosal vessels, kidney sections depicted tubular necrosis and in pancreas sections, hydropic degeneration of the pancreatic islets was observed. In conclusion, HlMeOHe damaged the liver with an oral dose of 200 mg/kg, and at 1000 mg/kg injured the kidneys and pancreas of the CD1 male mice

Tumor necrosis factor haplotype diversity in Mestizo and Native populations of Mexico

The so-called tumor necrosis factor (TNF) block includes the TNFA, lymphotoxin alpha and beta (LTA and LTB) genes with single-nucleotide polymorphisms (SNP) and microsatellites with an allele frequency that exhibits interpopulation variability. To date, no reports have included both SNPs and microsatellites at the TNF block to study Mestizo or Amerindian populations from Mexico. In this study, samples of five Mexican Mestizo populations (Durango, Guadalajara, Monterrey, Puebla, and Tierra Blanca) and four native-Mexican populations (North Lacandonians, South Lacandonians, Tepehuanos, and Yaquis) were genotyped for two SNPs (LTA+252A>G and TNFA-308G>A) and four microsatellites (TNFa, d, e, and f), to analyze the genetic substructure of the Mexican population. Allele and haplotype frequencies, linkage disequilibrium (LD), and interpopulation genetic relationships were calculated. There was significant LD along almost all of the TNF block but the lowest D' values were observed for the TNFf-TNFd pair. Mestizos showed higher allele and haplotype diversity than did natives. The genetic differentiation level was reduced among Mestizos; however, a slightly, but significant genetic substructure was observed between northern and southern Mexican Mestizos. Among the Amerindian populations, the genetic differentiation level was significantly elevated, particularly in both North and South Lacandonians. Furthermore, among Southern Lacandonians, inhabitants of Lacanja town were the most differentiated from all the Mexicans analyzed. The data presented here will serve as a reference for further population and epidemiological studies including these TNF polymorphisms in the Mexican population. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

Polluted water from an urban reservoir (Madín dam, México) induces toxicity and oxidative stress in Cyprinus carpio embryos

The Madín Dam is a reservoir located in the municipalities of Naucalpan and Atizapán, in the metropolitan area adjacent to Mexico City. The reservoir supplies drinking water to nearby communities and provides an area for various recreational activities, including kayaking, sailing and carp fishing. Over time, the number of specimens of common carp has notably diminished in the reservoir, which receives direct domestic drainage from two towns as well as numerous neighborhoods along the Tlalnepantla River. Diverse studies have demonstrated that the pollutants in the water of the reservoir produce oxidative stress, genotoxicity and cytotoxicity in juvenile Cyprinus carpio, possibly explaining the reduction in the population of this species; however, it is necessary to assess whether these effects may also be occurring directly in the embryos. Hence, surface water samples were taken at five sites and pharmaceutical drugs, personal care products (especially sunscreens), organophosphate and organochlorine pesticides, and other persistent organic pollutants (e.g., polychlorinated biphenyls and polycyclic aromatic hydrocarbons) were identified. Embryos of C. carpio were exposed to the water samples to evaluate embryolethality, modifications in embryonic development, lipoperoxidation, the quantity of hydroperoxide and oxidized proteins, and antioxidant enzyme activity (superoxide dismutase, catalase and glutathione peroxidase). It was found that the polluted water of the Madín Dam gave rise to embryolethality, embryotoxicity, congenital abnormalities, and oxidative stress on the common carp embryos. Capsule: The water of the Madín dam contains a complex mixture of pollutants, including hydrocarbons, which produce oxidative stress and embryotoxicity on Cyprinus carpio. © 2019 Elsevier LtdThis study was made possible by financial support from the Consejo Nacional de Ciencia y Tecnología (CONACyT-Mexico, project #181541 and Cátedras CONACyT, #282), and the Secretaría de Investigación y Posgrado of the Instituto Politécnico Nacional (SIP-IPN, project #20160871 and 20180699). We give thanks to Biologist Gerardo Ontiveros at the Centro Carpícola Tiacaque for supplying the test specimens and giving advice on their care and maintenance.Peer reviewe