The natural habitat of Paracoccidioides brasiliensis remains undefined but the repeated demonstration of infection by this fungus in the nine-banded armadillo Dasypus novemcinctus has opened interesting research avenues. We report here the isolation of this fungus from the spleen of a naked-tailed armadillo Cabassous centralis (Miller 1899) captured in a coffee farm localized in the Colombian endemic area for paracoccidioidomycosis. This particular isolate was identified by its dimorphism and also by comparison of the PbGP43 gene and ribosomal internal transcribed spacer regions (ITS) with recognized P brasiliensis strains. This finding extends the range of naturally acquired infections in mammals of the family Dasypodidae and confirms the existence of this human pathogen in areas where human paracoccidioidomycosis is known to occur.

At least 10% of the wetlands in Mexico are situated in the State of Veracruz on the central Gulf coast. The region has been intensively used for agriculture by humans for the last thousand years and today pastureland for cattle ranching is the dominant element of the landscape. We present a study of the wetland vegetation in a series of representative and internationally significant freshwater wetlands near the coastal lagoon La Mancha in Veracruz State. We obtained eleven wetland types formed by three wetland communities dominated by trees (mangrove or swamps), eight dominated by herbaceous species which we classified as marsh, five of which were native emergent marsh, one was a non-native emergent marsh and two were floating-leaved marsh. The highest diversity values were found in the Annona swamp, followed by the Sagittaria marsh and the Rhizophora-Laguncularia-Avicennia mangrove. CCA ordination showed that water level, disturbance and species number were the major factors explaining variation along axis 1, and on axis 2 conductivity, salinity, and bulk density. Wetland size was a major factor in both axes. We examined the interplay of intrinsic and extrinsic factors that give rise to the nature and diversity of wetland types that characterize the important wetland landscapes in this part of Mexico, being disturbance by human activities an important factor that favors the appearance of diverse species combinations.

SUMMARYThe precise microenvironment of Paracoccidioides brasiliensis has not yet been discovered perhaps because the methods used are not sensitive enough. We applied to this purpose the polymerase chain reaction (PCR) using three sets of specific primers corresponding to two P. brasiliensis genes. This fungus as well as several other fungi, were grown and their DNA obtained by mechanical disruption and a phenol chloroform isoamylalcohol-based purification method. The DNA served for a PCR reaction that employed specific primers from two P. brasiliensis genes that codify for antigenic proteins, namely, the 27 kDa and the 43 kDa. The lowest detection range for the 27 kDa gene was 3 pg. The amplification for both genes was positive only with DNA from P. brasiliensis; additionally, the mRNA for the 27 kDa gene was present only in P. brasiliensis, as indicated by the Northern analysis. The standardization of PCR technology permitted the amplification of P. brasiliensis DNA in artificially contaminated soils and in tissues of armadillos naturally infected with the fungus. These results indicate that PCR technology could play an important role in the search for P. brasiliensis' habitat and could also be used in other ecological studies.

El aprendizaje cooperativo es considerado por diversos autores como un método que permite desarrollar potencialidades para trabajar en equipo a través de una forma de organización social del grupo, la cual facilita que cada miembro del equipo despliegue habilidades, destrezas y valores basados en sus propias potencialidades, las mismas que han sido identificadas y maximizadas por el docente intencionadamente para garantizar una correcta cohesión de equipo. Se realizó una experiencia en la asignatura de Derecho Internacional Privado, en la cual se evidencia, según las valoraciones del equipo metodológico, que los estudiantes desarrollaron habilidades en el discurso oral y escrito, mejorando a su vez las relaciones de interdependencia con sus pares con habilidades desarrolladas. Ellos se mostraron más responsables por el proceso de la tarea, por lo que se formaron aspectos personológicos fundamentales en el ejercicio del derecho.

-The aim of this study is to register the presence of aquatic insects during the rainy and dry seasons, in 15 dune lakes of the Gulf of Mexico's coastal zone. These ecosystems lodge a wealth of 62 families, 60 of them present during the rainy season and 46 during the dry period. At both times Coleoptera is the order with a greater number of families, followed by Diptera. The first one is the most diverse, but Chironomidae (Diptera) is the most abundant, representing 40% of the total number of individuals. We used high rank taxa to quantify the biodiversity based on the principle that a high number of families or genus is supposed to include a greater number of species. There were not significant differences in the alpha diversity within the same lake during the two climatic seasons. The trophic structure is dominated by the detritivorous groups (57% of scrapers, collectors, gatherers, shredders), followed by predators (38%) and herbivores (5%). These numbers indicate that dune lakes have a great amount of organic matter. The results obtained contradict our working hypothesis, thus it was rejected, in summary, because there were no important differences in family composition, abundance of individuals and trophic structure of the lakes between the rainy and dry seasons.KEY WORDS: Wetland, biodiversity, higher taxa RESUMEN -El objetivo de este trabajo fue registrar la presencia de insectos acuáticos durante la estación de lluvias y durante las secas en 15 lagos interdunarios localizados en la zona costera del Golfo de México. Estos sistemas albergan una riqueza de 62 familias en general, registrándose en época de lluvias un total de 60 familias y en secas 46. En ambas épocas Coleoptera es el orden con mayor número de familias seguido de Diptera. A pesar que la primera es la más diversa no es la más abundante, ya que la familia Chironomidae (Diptera) engloba un 40% de la abundancia total de individuos capturados. La utilización de taxa de alto rango para cuantificar la biodiversidad se basa en el principio de que un número elevado de géneros y/o familias se supone que alberga un mayor número de especies. No se encontraron diferencias significativas en la riqueza de familias entre la época de secas y la de lluvias para cada lago. La estructura trófica encontrada está dominada por familias de detritófagos (57%), seguido de los depredadores (38%) y el resto son herbívoros. Ello es un indicador de que estos cuerpos de agua presentan gran cantidad de materia orgánica. Con los resultados que se obtuvieron nuestra hipótesis de trabajo se rechazó, ya que no se encontraron diferencias en la riqueza, diversidad y estructura trófica de los lagos entre las épocas de secas y las de lluvias.PALABRAS CLAVE: Humedal, biodiversidad, taxa alto rango Existen diferentes tipos de humedales, y entre los más particulares están aquellos asociados a sistemas de dunas costeras. Estos humedales se forman en las depresiones que se producen entre los cordones y brazos de las dunas, las cuales están en contacto con el manto freático. Cu...