The heavy metal mercury is a known toxin, but while the mechanisms involved in mercury toxicity have been well demonstrated in vertebrates, little is known about toxicological effects of this metal in invertebrates. Here, we present the results of our study investigating the effects associated with exposure of fruit fly Drosophila melanogaster to inorganic mercury (HgCl 2 ). We quantify survival and locomotor performance as well as a variety of biochemical parameters including antioxidant status, MAPK phosphorylation and gene expression following mercury treatment. Our results demonstrate that exposure to Hg(II) through diet induced mortality and affected locomotor performance as evaluated by negative geotaxis, in D. melanogaster. We also saw a significant impact on the antioxidant system including an inhibition of acetylcholinesterase (Ache), glutathione S-transferase (GST) and superoxide dismutase (SOD) activities. We found no significant alteration in the levels of mRNA of antioxidant enzymes or NRF-2 transcriptional factor, but did detect a significant up regulation of the HSP83 gene. Mercury exposure also induced the phosphorylation of JNK and ERK, without altering p38 MAPK and the concentration of these kinases. In parallel, Hg(II) induced PARP cleavage in a 89 kDa fragment, suggesting the triggering of apoptotic cell death in response to the treatment. Taken together, this data clarifies and extends our understanding of the molecular mechanisms mediating Hg(II) toxicity in an invertebrate model. # 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 621-630, 2014.
Manganese (Mn)-containing dithiocarbamates such as Mancozeb (MZ) have been shown to induce oxidative stress-related toxicity in rodents and humans. However, little is known about the neurotoxic effects induced by MZ in fish. In this study, carp (Cyprinus carpio) were exposed to non-lethal waterborne concentrations of MZ, and oxidative stress parameters as well as metal accumulation in fish brains were evaluated. The experimental groups were as follows: control, MZ 5 mg/L, and MZ 10 mg/L. Fish were exposed for 7 days, and then brain was removed and prepared for subsequent analysis of antioxidant enzymes, reactive oxygen species (ROS), and expression of Nrf2 and phosphoNrf2. In parallel, manganese (Mn) levels were evaluated in blood and brain tissues. Mn levels were significantly increased in blood and brain of MZ-exposed carps. In addition, a concentration-dependent increase (p < 0.05) in ROS levels was observed in parallel to increments (p < 0.05) in the activity of major antioxidant enzymes, such as GPx, GR, and GST. On the other hand, significant decreases (p < 0.05) in CAT and SOD activities were observed. The expression of total and phosphorylated forms of Nrf2 was significantly (p < 0.05) upregulated in the brain of carps exposed to Mz when compared to the control, indicating an activation of the Nrf2 antioxidant pathway. Our study showed for the first time the activation of the Nrf2/ARE pathway and bioaccumulation of Mn induced by MZ exposure in fish species, highlighting important mechanisms of action and its toxicological impacts to aquatic organisms.
Resumo: Atualmente, a dimensão ambiental está adquirindo, cada vez mais, importância nas ações das organizações e da sociedade. Hoje, os produtos são freqüentemente idealizados, produzidos, comercializados e consumidos levando em conta os impactos gerados em cada processo da cadeia produtiva orizícola. Uma grande preocupação deste setor é com os resíduos sólidos gerados na indústria de beneficiamento do arroz. Por isso, este trabalho tem como objetivo identificar os resíduos sólidos oriundos de uma agroindústria beneficiadora de arroz e propor melhorias para a sua destinação. Essa pesquisa foi realizada em uma agroindústria beneficiadora de arroz, localizada no município de São Sepé/RS, no período entre os meses de abril a junho de 2010. O mapeamento adotado segue uma observação estruturada. Foram identificados no mapeamento vinte e um tipos de resíduos resultantes do processo, sendo os que foram observados em maior quantidade a cinza e a casca de arroz. O diagnóstico realizado permite a empresa conhecer melhor o seu funcionamento, propor melhorias e fazer uma revisão periódica dos resíduos sólidos gerados no processo produtivo. Por fim, se propôs estratégias para o redirecionamento dos resíduos minimizando problemas ambientais.
Resumo
Nos últimos tempos, as ações antrópicas estão sendo apontadas como responsáveis por inúmeros problemas para saúde humana. O principal objetivo deste trabalho foi verificar indicativos para possíveis problemas da
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