Histological changes in gills, kidney and liver were used to evaluate the health of the Neotropical fish species Prochilodus lineatus, subjected to in situ tests for 7 days in a disturbed urban stream and in a reference site, during winter and summer. In fish caged in the urban stream the most common lesions were epithelial lifting, hyperplasia and hypertrophy of the respiratory epithelium, lamellar fusion, and aneurysms in the gills; enlargement of the glomerulus, reduction of Bowman's space, occlusion of the tubular lumen, cloudy swelling and hyaline droplet degeneration in the kidneys; hepatocytes with hypertrophy, cytoplasmic and nuclear degeneration, melanomacrophage aggregates, bile stagnation and one case of focal necrosis in the liver. The lesions were comparatively most severe in the liver. Histopathology showed to be a very suitable biomarker for use in conjugation with the in situ test, because the seasonal variation did not interfere in the results and it was possible to differentiate the sites in the urban stream from the reference site.

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Histopathology of gills, kidney and liver of a Neotropical fish caged in an urban stream

This review considers the potential of the Comet assay (or Single Cell Gel Electrophoresis, SCGE) to evaluate the environmental impact of genotoxins in aquatic environments. It focuses on in vivo and in situ studies that have been carried out in various marine and freshwater sentinel species, published in the last 5 years. A large number of the studies reviewed report that the Comet assay is more sensitive when compared with other biomarkers commonly used in genetic ecotoxicology, such as sister chromatid exchanges or micronucleus test. Due to its high sensitivity, the Comet assay is widely influenced by laboratory procedures suggesting that standard protocols are required for both fish and mussel cells. However, there are still a wide variety of personalised Comet procedures evident in the literature reviewed, making comparison between published results often very difficult. Standardization and inter-laboratory calibration of the Comet assay as applied to aquatic species will be required if the Comet assay is to be used routinely by national bodies charged with monitoring water quality.

The Comet assay for the evaluation of genotoxic impact in aquatic environments.

Cytotoxicity of metals is important because some metals are potential mutagens able to induce tumors in humans and experimental animals. Chromium can damage DNA in several ways, including DNA double strand breaks (DSBs) which generate chromosomal aberrations, micronucleus formation, sister chromatid exchange, formation of DNA adducts and alterations in DNA replication and transcription. In our study, water samples from three sites in the Corrego dos Bagres stream in the Franca municipality of the Brazilian state of Sao Paulo were subjected to the comet assay and micronucleus test using erythrocytes from the fish Oreochromis niloticus. Nuclear abnormalities of the erythrocytes included blebbed, notched and lobed nuclei, probably due to genotoxic chromium compounds. The greatest comet assay damage occurred with water from a chromium-containing tannery effluent discharge site, supporting the hypothesis that chromium residues can be genotoxic. The mutagenicity of the water samples was assessed using the onion root-tip cell assay, the most frequent chromosomal abnormalities observed being: c-metaphases, stick chromosome, chromosome breaks and losses, bridged anaphases, multipolar anaphases, and micronucleated and binucleated cells. Onion root-tip cell mutagenicity was highest for water samples containing the highest levels of chromium.

/pdf/genotoxicity-and-mutagenicity-of-water-contaminated-with-2ovjd5xddx.pdf

Genotoxicity and mutagenicity of water contaminated with tannery effluents, as evaluated by the micronucleus test and comet assay using the fish Oreochromis niloticus and chromosome aberrations in onion root-tips

▪ Abstract When the enigmatic fish pathogen, the rosette agent, was first found to be closely related to the choanoflagellates, no one anticipated finding a new group of organisms. Subsequently, a new group of microorganisms at the boundary between animals and fungi was reported. Several microbes with similar phylogenetic backgrounds were soon added to the group. Interestingly, these microbes had been considered to be fungi or protists. This novel phylogenetic group has been referred to as the DRIP clade (an acronym of the original members: Dermocystidium, rosette agent, Ichthyophonus, and Psorospermium), as the class Ichthyosporea, and more recently as the class Mesomycetozoea. Two orders have been described in the mesomycetozoeans: the Dermocystida and the Ichthyophonida. So far, all members in the order Dermocystida have been pathogens either of fish (Dermocystidium spp. and the rosette agent) or of mammals and birds (Rhinosporidium seeberi), and most produce uniflagellated zoospores. Fish pathogens al...

The Class Mesomycetozoea: A Heterogeneous Group of Microorganisms at the Animal-Fungal Boundary*

Mutagenic and genotoxic effects of the Atrazine herbicide in Oreochromis niloticus (Perciformes, Cichlidae) detected by the micronuclei test and the comet assay

Evaluation of environmental waters using the comet assay in Tilapia rendalli

It is described the histopathology of the infection of Tilapia rendalli (Osteichthyes, Perciformes, Cichlidae) and Hypostomus regani (Osteichthyes, Siluriformes, Loricariidae) by lasidium larvae of Anodontites trapesialis (Mollusca, Bivalvia, Mycetopodidae). The larvae were encysted within the epidermis of the host, being surrounded by a thin hyaline membrane, 3-6 microm thick, of parasite origin. A proliferative host cell reaction did not occur. The histopathology of the infection shows that the lesions induced by the parasites are minimal. However, the numerous small lesions produced by the release of the larvae may provide optimal conditions for the infection by opportunistic pathogens, namely fungus, which may eventually cause the death of the host.

/pdf/the-histopathology-of-the-infection-of-tilapia-rendalli-and-g0sszlpsy2.pdf

The Histopathology of the Infection of Tilapia rendalli and Hypostomus regani (Osteichthyes) by Lasidium Larvae of Anodontites trapesialis (Mollusca, Bivalvia)

Deux kystes blanchâtres et allonges, observes dans la nageoire pectorale gauche de Trichomycterus sp. (Osteichthyes, Trichomycteridae) sont pleins de spores de Dermocystidium sp. Les spores sont spheriques et ont un gros corps central, opaque et PAS positif, le cytoplasme des spores est reduit a une mince couche peripherique contenant le noyau, les kystes sont enveloppes par une paroi mince et homogene, d'origine parasitaire. II n'y a pas d'encapsulation des kystes par les tissus de l'hote.

/pdf/a-dermocystidium-infection-in-trichomycterus-sp-osteichthyes-4j3z7t12bt.pdf

A Dermocystidium infection in Trichomycterus sp. (Osteichthyes, Trichomycteridae).

Diechodactylus joaberi n. g., n. sp. is described from the body surface of the banded knifefish Gymnotus carapo L. (Gymnotiformes: Gymnotidae) from southeastern Brazil. The new genus is proposed to accommodate species with five pairs of hooks in anterior bilateral clusters on the haptor, three pairs of hooks in a single cluster on the posterior margin of the haptor, sclerites R1 associated with the superficial bar, and confluent intestinal caeca. The presence of five pairs of hooks in two bilateral clusters anterior in the haptor permits the differentiation of species of Diechodactylus from species of all known genera of the Gyrodactylidae. The genus is likely a member of a clade of the Gyrodactylidae comprising genera with a similar hook distribution.

Neotropical Monogenoidea. 52. Diechodactylus joaberi n. g., n. sp. from the banded knifefish Gymnotus carapo (Gymnotiformes: Gymnotidae) in southeastern Brazil.

Specimens of the characid fish Brycon hilarii collected in dry and wet seasons in the River Juba, Tangara da Serra, State of Mato Grosso, Brazil, were surveyed for nematode parasites. Contracaecum sp. Type 1 and Type 2 larvae of Moravec, Kohn et Fernandes, 1993 were detected in the mesentery and liver, and Neocucullanus neocucullanus and Procamallanus (Spirocamallanus) inopinatus were observed in the intestine and pyloric caeca 75% of the nematodes were detected in the wet season. This is the first report of fish parasites from the River Juba and of the occurrence of Contracaecum larvae in B. hilarii.

/pdf/nematode-parasites-of-the-characid-fish-brycon-hilarii-from-44yxmm6r51.pdf

Angela Teresa Silva-Souza

Papers

Evaluation of environmental waters using the comet assay in Tilapia rendalli

The Histopathology of the Infection of Tilapia rendalli and Hypostomus regani (Osteichthyes) by Lasidium Larvae of Anodontites trapesialis (Mollusca, Bivalvia)

A Dermocystidium infection in Trichomycterus sp. (Osteichthyes, Trichomycteridae).

Neotropical Monogenoidea. 52. Diechodactylus joaberi n. g., n. sp. from the banded knifefish Gymnotus carapo (Gymnotiformes: Gymnotidae) in southeastern Brazil.

Nematode parasites of the characid fish Brycon hilarii from the River Juba, Mato Grosso, Brazil