scholarly journals Study of the plastisphere: biofilm development and presence of faecal indicator bacteria on microplastics from the Río de la Plata estuary

Ecosistemas ◽  
2020 ◽  
Vol 29 (3) ◽  
Author(s):  
Rocío Soledad Pazos ◽  
Jimena Camila Suárez ◽  
Nora Gómez
Keyword(s):  
Aquatic Ecosystems ◽  
Indicator Bacteria ◽  
Intertidal Sediment ◽  
Rio De La Plata ◽  
Pathogenic Microorganisms ◽  
Land Uses ◽  
Río De La Plata ◽  
Faecal Indicator Bacteria ◽  
La Plata ◽  
Biofilm Development

Microplastics (MPs) are considered emerging pollutants and often enter aquatic ecosystems carried by currents and tides until they accumulate on the shorelines. In many cases they may be colonized by diverse microorganisms forming a community called plastisphere, which can even act as a reservoir for pathogenic microorganisms. This study carried out in the Río de la Plata estuary (southern coastal fringe, Argentina) focused on two main objectives, the analysis of the biofilm colonizing MPs under laboratory conditions, and the detection of bacteria indicating faecal contamination (Escherichia coli and Enterococci), in MPs from the intertidal sediment at coastal sites with different land uses, in the freshwater sector of the Río de la Plata estuary. The colonization experiment was carried out in the laboratory with water from the estuary for a period of 35 days (residence time of the water in the freshwater sector of the estuary). The results revealed a remarkable development and diversity of biofilm organisms from the second week of colonization on, covering the surface of the microplastic and thus masking this pollutant. On the other hand, the presence of faecal indicator bacteria in the MPs of the intertidal sediment was confirmed in all the studied sites, being proportionally higher on MPs found in areas influenced by sewage discharges.

Acido delta-aminolevulínico dehidrasa (ALA-D) como biomarcador de exposición a plomo en peces

2008 ◽  
Author(s):  
◽  
Paula Edith Lombardi
Keyword(s):  
Cyprinus Carpio ◽  
Buenos Aires ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
Prochilodus Lineatus ◽  
La Plata ◽  
Del Rio

La actividad de la enzima ácido δ-aminolevulínico dehidrasa (ALA-D) es un reconocido biomarcador específico de exposición a plomo. Debido a sus características ha sido utilizado en estudios de monitoreo ambiental para evaluar la exposición a plomo en diversos organismos, entre ellos peces. El principal objetivo del presente trabajo de tesis fue validar un método de evaluación general de riesgo ecotoxicológico por exposición a plomo en poblaciones naturales de peces. Para tal fin se seleccionaron tres especies recolectadas del río de la Plata: Prochilodus lineatus (sábalo), Leporinus obtusidens (boga) y Cyprinus carpio (carpa). Las zonas de muestreo elegidas fueron: Berazategui y Berisso ubicadas cerca de las emisiones de residuos cloacales provenientes de las ciudades de Buenos Aires y La Plata. La tercera, Atalaya, libre de emisiones cloacales, pero sujeta a emisiones diversas, todas ellas, de origen antropogénico. Los muestreos se realizaron entre junio de 2002 y mayo de 2004. En primera instancia se caracterizaron diversos parámetros de la enzima ALA-D en muestras de sangre y de tejido hepático. Los resultados obtenidos mostraron características similares en la enzima sanguínea de todas las especies estudiadas. Lo mismo se observó para la enzima hepática. La comparación entre tejidos mostró diferencias en el valor de Km, siendo menor para la enzima hepática. Posteriormente, se procedió a validar el uso de la enzima como parámetro biomarcador de exposición a plomo en estudios de campo.

Poe and His Global Advocates

2018 ◽  
pp. 596-617
Author(s):  
Emron Esplin
Keyword(s):  
Twentieth Century ◽  
South America ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
Literary Traditions ◽  
La Plata ◽  
Original Works ◽  
Definition Of ◽  
Global Reputation

This essay explores Edgar Allan Poe’s extraordinary relationships with various literary traditions across the globe, posits that Poe is the most influential US writer on the global literary scene, and argues that Poe’s current global reputation relies at least as much on the radiance of the work of Poe’s literary advocates—many of whom are literary stars in their own right—as it does on the brilliance of Poe’s original works. The article briefly examines Poe’s most famous French advocates (Baudelaire, Mallarmé, Valéry); glosses the work of his advocates throughout Europe, Asia, and the Americas; and offers a concise case study of Poe’s influence on and advocacy from three twentieth-century writers from the Río de la Plata region of South America (Quiroga, Borges, and Cortázar). The essay concludes by reading the relationships between Poe and his advocates through the ancient definition of astral or stellar influence.

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