Liver dysfunction and energy storage mobilization in traíra, Hoplias malabaricus (Teleostei, Erythrinidae) induced by subchronic exposure to toxic cyanobacterial crude extract.

Microcystins (MC) are hepatotoxic for organisms. Liver MC accumulation and structural change are intensely studied, but the functional hepatic enzymes and energy metabolism have received little attention. This study investigated the liver and hepatocyte structures and the activity of key hepatic functional enzymes with emphasis on energetic metabolism changes after subchronic fish exposure to cyanobacterial crude extract (CE) containing MC.

Biochemical and morphological biomarker responses in the gills of a Neotropical fish exposed to a new flavonoid metal-insecticide.

The flavonoid metal-insecticide [Mg(hesp)(phen)], denominated MgHP, has high potential for controlling agricultural pests. If applied in large scale, it may reach aquatic ecosystems and be harmful to the biota. This study evaluated the effects of MgHP in the gills of the Neotropical fish, Prochilodus lineatus by determining the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione s-transferase (GST), and the levels of glutathione (GSH) and lipid peroxidation (LPO) after 24 and 96 h exposure to 0, 1, 10, 100 and 1000 μg L.

Biotransformations, Antioxidant System Responses, and Histopathological Indexes in the Liver of Fish Exposed to Cyanobacterial Extract.

Radiocystis fernandoi, a microcystin (MC) producer, has been common in cyanobacterial blooms in tropical regions. Microcystin is a hepatotoxin that causes tissue damage and even death in animals, including humans; its detoxification process may involve biotransformation and activation of the antioxidant defense system. We evaluated the detoxification pathway, examined the antioxidant defense system responses, and determined the alterations and the organ histopathological indexes in the liver of the tropical fish Hoplias malabaricus after acute and subchronic intraperitoneal exposure to microcystin.

Crude extract of cyanobacterium Radiocystis fernandoi strain R28 induces anemia and oxidative stress in fish erythrocytes.

The cyanobacterium Radiocystis fernandoi has been frequently identified in cyanobacterial blooms in Brazil. Recently, R. fernandoi strain R28, which produces microcystin (MC)-RR and MC-YR, was isolated from the Furnas reservoir, Minas Gerais, Brazil.

Differential biochemical responses to metal/metalloid accumulation in organs of an edible fish (Centropomus parallelus) from Neotropical estuaries.

Metal/metalloid accumulation in fish organs elicits biochemical responses indicating the overall fish and environmental health status. This study evaluated the bioaccumulation of metals and metalloid in relation to a suite of biochemical biomarkers (superoxide dismutase, catalase, glutathione-S-transferase, Na+/K+-ATPase, H+-ATPase, acetylcholinesterase activities and the levels of glutathione, metallothionein, lipid peroxidation and oxidized protein) in different organs of fish, Centropomus parallelus, in Vitória Bay and Santa Cruz estuaries (State of Espírito Santo, Brazil) with distinct contamination levels. Metal and metalloid concentrations differ in each organ and were significantly higher in winter than in summer.

Hepatotoxicity and metabolic effects of cellular extract of cyanobacterium Radiocystis fernandoi containing microcystins RR and YR on neotropical fish (Hoplias malabaricus).

The toxicological effect of cellular extract of cyanobacterium Radiocystis fernandoi strain R28 containing RR and YR microcystins was analyzed in the fish Hoplias malabaricus with emphasis on the liver structure and energetic metabolism, after short-term exposure. Fish were intraperitoneally (i.p.

Subchronic exposure to diflubenzuron causes health disorders in neotropical freshwater fish, Prochilodus lineatus.

The action of diflubenzuron (DFB) was evaluated in a freshwater fish, Prochilodus lineatus, after exposure to 0.06, 0.12, 0.

The impact of organochlorines and metals on wild fish living in a tropical hydroelectric reservoir: bioaccumulation and histopathological biomarkers.

This study evaluates the contaminants in water and their bioaccumulation in the gills and liver of two ecologically distinct fish species, Astyanax fasciatus and Pimelodus maculatus, living in the reservoir of the Furnas hydroelectric power station located in Minas Gerais in the southeastern Brazil. The histological alterations in these organs are also examined. Water and fish were collected in June and December from five sites (site 1: FU10, site 2: FU20, site 3: FU30, site 4: FU40 and site 5: FU50) in the reservoir, and agrochemicals and metals selected based on their use in the field crops surrounding the reservoir were analyzed in the water and in the fish gills and livers.

Using condition factor and blood variable biomarkers in fish to assess water quality.

The condition factor and blood variables, including erythrocyte lipid peroxidation (LPO) and the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), in two ecologically distinct fish species (Astyanax fasciatus and Pimelodus maculatus) were evaluated at five sites in the Furnas Hydroelectric Power Station reservoir (Brazil) to assess water quality. Aldrin/dieldrin, endosulfan, heptachlor epoxide, and metolachlor were detected at different concentrations in four of the sites. Condition factor was not directly affected by such contaminants.

Functional morphology of the gill in amazonian freshwater stingrays (chondrichthyes: potamotrygonidae): implications for adaptation to freshwater.

The gill morphologies of six species of potamotrygonid freshwater stingrays from the Amazon basin were investigated using light and electron microscopy. Some unique features were found in the potamotrygonid gill: (1) fingerlike protuberances on the gill filament, (2) an Alcian blue/periodic acid-Schiff-positive histochemical reaction for several cell layers in the gill epithelium (except the basal ones), (3) pavement cells with numerous subapical mucous vesicles, (4) very large mucous cells, and (5) follicular Na(+)/K(+)-ATPase-rich (NKA-rich) mitochondria-rich cells (MRCs) in Potamotrygon sp. (known as the cururu ray).