Austrodiplostomum
Szidat & Nani, 1951 is a genus of parasitic digenetic trematodes widely distributed in the Neotropical region. Infects a wide variety of species, families and requests for freshwater fish. We identify samples of
Austrodiplostomum
sp, based on metacercariae isolates from eyes of tambaqui (
Colossoma macropomum
), a fish of high commercial importance in Brazil, and widely consumed by the population of the northern region. The sequences obtained clustered with
A. compactum
. This is the first report of the occurrence of diplostomids in farmed tambaqui in Amazonia.
Classified as a class II organophosphate and considered highly toxic, trichlorfon is a drug widely used in worldwide pisciculture for the treatment of parasites in farming ponds. It is used for the treatment of several fish species, both in natural and artificial ponds. The main action of trichlorfon occurs in the nervous system of fish by blocking the enzyme acetylcholinesterase and causing acetylcholine accumulation, which leads to the constant passage of neural transmission. However, several studies show that trichlorfon can be more harmful to the fish than to the parasite that the drug is trying to eliminate. Our article brings a review of the main effects of trichlorfon in several fish species around the world, in order to further evaluate these side effects and help researchers to understand this drug
No Brasil existem diversos produtos antiparasitários aprovados para uso na aquicultura. O triclorfon é um composto organofosforado com efeito genotóxico e amplamente utilizado para controlar uma variedade de ectoparasitoses na piscicultura. Em contato com a água sofre hidrólise e forma um metabólito potencialmente mais tóxico, o diclorvós. A biotransformação pode reduzir a meia-vida do xenobiótico diminuindo seu potencial tóxico. As enzimas da superfamília citocromo P450 (CYP) fazem parte da desintoxicação de muitos agroquímicos em peixes e são importantes na biossíntese e metabolismo de compostos endógenos. As respostas mensuradas ao nível de gene, assegura a aplicação destes biomarcadores moleculares como ferramentas de monitoramento para avaliar o impacto dos contaminantes no meio ambiente. Desse modo, o presente estudo realizou uma revisão de literatura para entender sobre os mecanismos e respostas da CYP450 em peixes contaminados e suas principais vias metabólicas.
Transcriptionally inactive portions of genomic DNA, condensed with histones and architectural proteins, are known as heterochromatic regions, often positive C band. The advent of epigenetics and new methodological approaches, showed that these regions are extremely dynamic and responsive to different types of environmental stress. The relationship of the constitutive heterochromatin with the transposable elements inactivation, especially from the Rex family, seems to be a frequent condition in fish. In this manuscript we review the existing knowledge of the nature and function of these genomic regions, based on species-based studies, with a focus on species of fish from the Amazon region.
Rex retroelements are the best-known transposable elements class and are broadly distributed through fish and also individual genomes, playing an important role in their evolutionary dynamics. Several agents can stress these elements; among them, there are some parasitic compounds such as the organochlorophosphate Trichlorfon. Consequently, knowing that the organochlorophosphate Trichlorfon is indiscriminately used as an antiparasitic in aquaculture, the current study aimed to analyze the effects of this compound on the activation of the Transposable Elements (TEs) Rex1, Rex3, and Rex6 and the structure of heterochromatin in the mitotic chromosomes of the tambaqui (Colossoma macropomum). For this, two concentrations of the pesticide were used: 30% (0.261 mg/L) and 50% (0.435 mg/L) of the recommended LC50–96 h concentration (0.87 mg/L) for this fish species. The results revealed a dispersed distribution for Rex1 and Rex6 retroelements. Rex3 showed an increase in both marking intensity and distribution, as well as enhanced chromosomal heterochromatinization. This probably happened by the mediation of epigenetic adaptive mechanisms, causing the retroelement mobilization to be repressed. However, this behavior was most evident when Trichlorfon concentrations and exposure times were the greatest, reflecting the genetic flexibility necessary for this species to successfully adapt to environmental changes.
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