Margarita González

Effects of pulp and paper mill discharges on caged rainbow trout (Oncorhynchus mykiss): Biomarker responses along a pollution gradient in the Biobio River, Chile

Caging experiments were conducted using hatchery-reared, immature, female rainbow trout (Oncorhynchus mykiss) in three previously defined areas of the Biobio River (south central Chile) representing a pollution gradient from the pulp and paper mill discharges area: a pre-impact area (upstream area, reference location), an impact area (area directly influenced), and a postimpact area (downstream area, less influenced). No significant changes were observed in the physiological index as represented by condition factor (K) and liver somatic index during different sampling times (after 11, 21, and 30 d of exposure). Ethoxyresorufin-O-deethylase activities were significantly higher in trout caged at the impact and postimpact discharges areas (two- to fourfold) compared with the reference (pre-impact) area, and a strong inhibition of acetylcholinesterase activity, reaching 50%, was observed mainly in fish caged at the impact area. A significant endocrine-disrupting effect (reproductive level) was evidenced by significant increments in gonad somatic index and plasma vitellogenin levels combined with an induction of gonad maturation (presence of vitellogenic oocytes) in trout caged at the impact and postimpact areas. These results, generated by an in situ approach, confirmed our groups findings for trout exposed to sediment in the laboratory: discharges of pulp mill effluent in the Biobio River are associated with the effects evaluated at different biological levels.

Reproductive, physiological, and biochemical responses in juvenile female rainbow trout (oncorhynchus mykiss) exposed to sediment from pulp and paper mill industrial discharge areas

Four pulp and paper mills discharge their effluents in the same section of the Biobio River in central southern Chile. Pulp mill effluents are a very complex mixture with characteristics that depend on the type of raw material, the process technology, and the effluent treatment. To investigate the effect of pulp mill effluent discharges, immature Oncorhynchus mykiss were exposed to river sediments in the laboratory for 29 d. Three sampling areas were defined in a spatial gradient in the river: Preimpact, impact, and postimpact zones relative to the pulp and paper mill discharge areas. Ethoxyresorufin-O-deethylase activities were significantly higher in fish exposed to impact and postimpact sediments when compared to those exposed to preimpact sediments, and higher levels of vitellogenin were observed in the plasma of female fish exposed to impact and postimpact sediments. Histological analysis of the gonadal tissue showed an induction of gonadal maturation in fish exposed to sediment coming from the impact and postimpact zones (oocytes in a vitellogenic state). No site differences were observed in erythrocytes, although differences were noted in the leukocytes in the exposure areas. Finally, the biomarker approach showed evidence that the sediment associated with pulp mill effluent discharges produces some effects in fish under laboratory conditions.

Detection of anchoveta (Engraulis ringens Jenyns 1842) eggs in euphausiid diets using immunoassays (ELISA)

Employing the production of a polyclonal antibody and the use of indirect enzyme linked immuno sorbent assay (ELISA), we detect Engraulis ringens egg proteins in the guts of a natural predator Euphausia mucronata Sars 1883 in Chilean waters. With a dilution of 1:15,000, the immune serum allowed the detection of 0.1 μg of anchoveta egg protein. The immune serum showed low cross-reactions with eggs and larval proteins of other pelagic fishes. Laboratory feeding experiments showed a window of detection of the protein of 9 h (13 °C) in the digestive tract of E. mucronata. In field-collected euphausiids within the spawning area of the anchoveta in Northern Chile, we detected anchovy egg proteins in 18% of 155 euphausiids tested by ELISA. These results constitute the first field evidence of predation by the highly abundant euphausiid E. mucronata on the early life stages of the anchoveta E. ringens in the Humboldt Current.

Assessment of persistent organic pollutants and their relationship with immunoglobulins in blood of penguin colonies from Antarctica

ABSTRACT: Persistent organic pollutants (POPs) may affect the immune system of seabirds, and some field studies have examined this effect. There are evidences that POPs cause negative effects on the immune system, but in Antarctic penguins data are scarce. In order to assess the risks that POPs may have on wild animals, some immunological studies constitute a good alternative. Determining the levels of immunoglobulins can deliver relevant information about the potential impact of POPs in seabirds from different environments. However, there are very few records in penguins so far. The aim of the present work was to quantify the concentrations of polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (LDDT), endosulfans, and immunoglobulin IgY in blood samples of colonies of chinstrap penguins (Pygoscelis antarctica) that inhabit in the Antarctic Peninsula area. Analysis of POPs in blood samples was carried out through extraction with QuEChERS method, followed by gas chromatography. Detection of IgY concentrations was achieved by ELISA test, using anti-chicken antibodies. There was some significant correlation between immunoglobulin and the presence of PCBs and endosulfans. Even though the levels of these pollutants are low to cause any biological effect on the birds, the results are indicating some influence on the IgY concentrations in penguin blood.

Descripción fenotípica y avances en la obtención de un inmunógeno contra partículas de virus ISA (HPR7b), aisladas desde un salmón del Atlántico de vida libre capturado en el ecosistema Sur-Austral de Chile

Se aislaron particulas del virus ISA cepa HPR7b, desde un salmon Atlantico capturado en el ecosistema Sur Austral de Chile. Se describe por primera vez la morfologia de este genotipo mediante microscopia electronica de transmision. Se estimulo la produccion de anticuerpos policlonales contra esta cepa en conejos: observandose respuesta positiva de hemaglutinacion a partir del segundo sangrado.