Search

The rapid increase in use of nanotechnology products is increasing the presence of metal, metal-oxide and carbon-based nanoparticles in the aquatic environment. These non-functionalized engineered nanoparticles can interact with the immune system of fish and invertebrates, and tip the ecological balance of population sustainability. Most nanoparticle types present in the aquatic environment, such as titanium dioxide, do not exhibit or have very low direct toxicity, but instead display silent or concealed sub-lethal effects on the immune system with serious implications. There is a gap in current available information regarding the immunotoxic potential of engineered nanoparticles toward aquatic organisms. Therefore, there is a critical need to provide the first comprehensive review of the effects of engineered non-functionalized nanoparticles on the immune system of aquatic animals, address the major gaps in current existing information, and recommend the future focus of research. This manuscript identifies cell mediated immunity and the phagocytic cells as the primary target of nanoparticle immunotoxicity. The immunotoxicity is primarily govern by lysosomal destabilization, frustrated phagocytosis, and change in function of the phagocytic cells, which decrease the ability of animals to defend themselves against pathogens and infectious diseases. Humoral immune system is a lesser target of direct immunotoxicity, but plays a critical role in dissemination of the nanoparticles through the body and their presentation to the phagocytic cells. The external innate immunity and the acquired immunity have not been connected with overly important and direct immunotoxic effects, but instead a big gap in current targeted research has been acknowledged., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Studies of innate immunity in fish species of special concern are essential for better understanding of their health status during hatchery rearing conditions. The cytochemical and morphological characterizations of blood granulocytes have been used to provide information about phylogenetic differences and determine the potential use of neutrophil function assays. Rapid, simple, cytochemical staining kits used routinely for staining mammalian granulocytes have been used to characterize granulocytes from blood of four fish species: Arctic grayling, cutthroat trout, June sucker, and shovelnose sturgeon. Blood smears were stained with Peroxidase 391 (myeloperoxidase, MPO), alkaline phosphatase (AP), Periodic Acid Schiff (PAS) and Diff-quick stain; examined using bright field and differential interference contrast microscopy. Granulocytes on blood smears were evaluated based on the cell morphology, and presence or absence of the specific chromogen. Presence of lymphocytes, monocytes, platelets/thrombocytes and granulocytes was determined in all fish species. Arctic grayling, June sucker, and cutthroat trout had MPO positive granulocytes, while shovelnose sturgeon heterophils had positive reaction for leukocyte AP, but not MPO. Presence of MPO indicated potential to measure oxidative burst and degranulation of neutrophil primary granules in Arctic grayling, cutthroat trout and June sucker. Absence of MPO in shovelnose sturgeon suggested use of different enzyme marker (AP) in degranulation assay for this species. Standardization of cytochemical techniques allowed for rapid screening of leukocyte types, reducing the number of fish, time and effort to select adequate neutrophil function assays to be used in studies of health status in species of special concern., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

We characterized the fish assemblages in second to fifth order streams of the upper Little Sioux River basin in northwest Iowa, USA and compared our results with historical surveys. The fish assemblage consisted of over twenty species, was dominated numerically by creek chub, sand shiner, central stoneroller and other cyprinids, and was dominated in biomass by common carp. Most of the species and the great majority of all individuals present were at least moderately tolerant to environmental degradation, and biotic integrity at most sites was characterized as fair. Biotic integrity declined with increasing stream size, and degraded habitat in larger streams is a possible cause. No significant changes in species richness or the relative distribution of species' tolerance appear to have occurred since the 1930s. [ABSTRACT FROM AUTHOR]

Abstract: Anesthetic efficacy, plasma cortisol concentration, and two parameters of neutrophil function (oxidative burst and degranulation of primary granules) were compared among three anesthetics in the fathead minnow: tricaine methanesulfonate (MS 222), metomidate hydrochloride (MTMD), and eugenol (EUG). The optimum anesthetic concentration was determined as: MS 222 75 mg L−1, EUG 30 mg L−1 and MTMD 4 mg L−1. Handling and crowding stress was induced in fish with (SA) and without (S) anesthetic. Plasma cortisol concentration was measured at 0, 30, 90, and 240 min after stress and found to increase at 30 min post-stress in S and SA MS 222 groups, but not in SA MTMD and SA EUG groups. To test the effects of different anesthetics on neutrophil function, fish were divided into a baseline control group, a group exposed to handling and crowding stress (S) and a stressed anesthetized group (SA). Fish were assayed for neutrophil function before and after stress (24 h, 72 h and 7 days). The degranulation of neutrophil primary granules was measured as exocytosis of myeloperoxidase (MPO) using 3, 3′, 5, 5′-tetramethylbenzidine as a substrate. Degranulation of primary granules was decreased to 60–75% of non-stressed control in stressed and fish treated with MS 222, and was not affected when MTMD and EUG were used. The degranulation of primary granules proved to be a useful assay for measuring the effects of stress on neutrophil function in fish. Eugenol and metomidate prevented stress-induced decrease of neutrophil function while MS 222 did not. [Copyright &y& Elsevier]

Chlorpyrifos (CPF) is one of the most common insecticides found in freshwater ecosystems, and has been detected in agricultural and fishery products worldwide. This study focused on comprehensive panel of hematological, immunotoxic and pathology changes in Nile tilapia ( Oreochromis niloticus ) during and after exposure to CPF at 15 μg/L (0.043 μM) (1/10 LC 50 , group CPF1), or 75 μg/L (0.21 μM) (1/2 LC 50 , group CPF2) for 14 days, followed by 2 weeks recovery. Different endpoints were used to determine effects of CPF on fish health: hematological parameters; antioxidant levels in liver and gills; innate immune parameters; expression levels of pro-inflammatory cytokine genes at mRNA level in anterior kidney and spleen; and histopathological assessment of gills, liver, and kidney tissues. RBCs were significantly decreased in CPF1 group compared to other groups only at day 3. Blood packed cell volume (PCV) and mean corpuscular volume (MCV) showed significant increase at day 3 and 14 of CPF exposure. TLC (Total Leukocytic Counts), neutrophil counts were significantly increased in CPF exposed groups at days 3, 7, 14 compared to the control. While, lymphocytes counts were significantly increased at CPF1 group compared to other groups at day 14. Antioxidant enzyme activity in liver and gills showed significant increase of Malondialdehyde (MDA) and glutathione (GSH), and significant decrease in (catalase/CAT/, glutathione S-transferase/GST/, and superoxide dismutase/SOD/); in CPF exposed groups. Serum bactericidal and lysozyme activity was nominally and significantly decreased, respectively, and whole blood respiratory burst was significantly increased in CPF2 group. The cytokine expression levels showed complex changes in expression patterns. In kidney, cytokine interleukin-8 (IL-8) was significantly upregulated at day 1 in both exposed group. Interleukin-1β (IL-1β) and Tumor necrosis factor-α (TNFα) were significantly upregulated at day 1 in CPF1 group, and then IL-8 and TNFα downregulated at day 3 in same group. At day 7, only TNFα was up and downregulated in CPF1 and CPF2, respectively compared to control. All gene expression levels in spleen were upregulated on day 7 of exposure in the high exposed group. Histopathology showed dose-dependent changes in CPF treated groups, indicating gill, liver, and posterior kidney changes associated with oxidative stress damages. Following recovery period, all measured parameters showed varying degrees in their reversibility to the control level. These findings provide important insights about the acute toxic effects of CPF on fish and show potential to be used as biomarkers in further toxicological evaluation studies. [ABSTRACT FROM AUTHOR]