RESUMO
Zoosporic organisms are common inhabitants of aquatic environments; however there are few ecological studies made for Argentinean streams. In this contribution the taxonomic composition of zoosporic organisms from a stream and their abundance, frequency and diversity on cellulosic baits were analyzed. Samples of water and floating organic matter (vegetable debris) were taken at four dates and different environmental variables (temperature, dissolved oxygen and nutrient concentrations) were measured. Twenty-one taxa were recovered with the baiting technique. Physicochemical fluctuations affected the structure of the studied community; in spring the greatest species richness was related to high nutrient levels whereas in winter the greatest abundance and diversity was related to low water temperature, nutrient levels and well oxygenated conditions. aquatic environment,
Assuntos
Biodiversidade , Água Doce/microbiologia , Fungos/isolamento & purificação , Esporos Fúngicos/isolamento & purificação , Argentina , Fungos/química , Fungos/classificação , Estações do Ano , Esporos Fúngicos/química , Esporos Fúngicos/classificação , TemperaturaRESUMO
The present contribution is the first report of parasitosis by a chytrid fungus in wild anuran amphibians in Argentina, as well as the first case of amphibian mortality documented to date in Argentina. We report the presence of the chytrid fungus in dead adult Leptodactylus ocellatus. It has been suggested that chytridiomycosis is the main cause of death in several amphibian populations worldwide. Our study demonstrates that chytridiomycosis afflicts L. ocellatus, a common widespread amphibian species, and is the first report of chytridiomycosis in the Argentinian lowlands. The occurrence at this latitude would indicate an extended distribution of this fungus in wildlife populations. It is also the first report of amphibian mortality due to chytrid fungus in our country. It is noteworthy that the site of collection is situated very close to sea level in a temperate climate zone and that this represents the southern most record for South American wild amphibians.
Assuntos
Anuros/microbiologia , Quitridiomicetos , Dermatomicoses/epidemiologia , Dermatomicoses/veterinária , Animais , Argentina/epidemiologia , Evolução Fatal , Técnicas Histológicas/veterináriaRESUMO
Durante el año 1993-4, mediante el análisis mensual de muestras de agua y de materia orgánica flotante, se realizó un estudio cuanti-cualitativo de los hongos zoospóricos (oomycetes, chytridiomycetes) presentes en la laguna Vitel y sus tributarios (chascomús, de la provincia de Buenos Aires). Utilizándo anzuelos vegetales (semillas de cannabis sativa y brassica sp.), se aislaron 31 especies de hongos zoospóricos, de los cuales 16 son citadas por primera vez para Argentina. El análisis cuantitativo de sus propágulos totales por litro, determinó un mayor contenido en los períodos estacionales de otoño y primavera.
Assuntos
Ambiente Aquático , Oomicetos , Estudos de Avaliação como Assunto , Estudos de Avaliação como Assunto , ArgentinaRESUMO
Después de realizar un estudio cuali-cuantitativo de la miccobiota en la Laguna Vitel y tributarios fueron obtenidas 28 especies de hongos zoospóricos, a partir de muestras de agua y de materia orgánica flotante, a lo largo de 1 año. Se calculó la abundancia y frecuencia relativa de las especies pertenecientes a la Cl. Oomycetes y Chytridiomycetes (S.D.Mastigomycotina)
Assuntos
Flora Aquática , Fungos , CongressoRESUMO
Se ensayó la actividad enzimática de algunas Saprolegniales (Achlya americana, A. apiculata, A. oligacantha, A. polyandra, A. prolifera, Dictyuchus monosporus, Isoachlyatouroloides, Saprolegnia diclina y S. parasitica), en distintos medios sólidos. Estas especies fueron aisladas de materia orgánica flotante, en Río Santiago (Pdo. Ensenada, Provincia de Buenos Aires, Argentina), y se demostró que poseen actividad enzimática, in vitro, para la descomposición de pectina, celulosa, hemicelulosa, lignina y almidón