Genotoxicity of surface waters in Brazil

DNA damage and oxidative stress responses to pollution of Mytilus galloprovincialis L. from the Izmir Bay (Turkey): Seasonal evaluation

In the current study, the relationship between DNA damage and heavy metal pollutions was evaluated by sampling mussels from Izmir Bay (Turkey), which has different anthropogenic impacts in the Aegean Sea. M. galloprovincialis was selected as a bioindicator organism to determine the heavy metal amounts, SOD, CAT, TBARS levels and to detect the DNA damage in 4 different stations of Izmir Bay. A significant increase was detected in all heavy metals in the digestive gland tissue of the mussels collected from the Alsancak in summer compared to spring. Especially, Zn levels of gills and digestive glands of mussels collected from Alsancak in summer were detected 22.411 and 40.447 μg/g, respectively. According to MPI values, significant differences were determined in Urla and the highest accumulation was calculated in gill tissue. The activities of SOD and CAT enzymes were found at a very high level in mussel gills and glands at all stations except Urla in summer compared to them in spring. Additionally, TBARS levels were higher in mussel gills and gonad tissues at Inciralti and Urla stations in summer compared to spring samples. DNA damage classification in mussel hemocytes from all stations was identified according to the Comet assay. The test results showed that a statistically significant decrease in DNA% in comet tails in hemocytes of mussels collected from all stations in Summer was found compared to them in Spring. Also, at all stations except Alsancak, the genetic damage index decreased in summer compared to spring. While a positive correlation was detected between heavy metal pollution and DNA damage in mussels taken from Alsancak and Inciraltı (r = 0.734), a significant correlation was detected in Pasaport and Urla in both seasons (r = 0.999). This study indicates that heavy metal contaminations in the mussels of Izmir Bay are still an environmental problem on this area. DNA damage is an appropriate biomarker for genotoxicity evaluation even in low heavy metal contaminated areas.

Zebrafish neuromast sensory system: Is it an emerging target to assess environmental pollution impacts?

Environmental pollution poses risks to ecosystems. Among these risks, one finds neurotoxicity and damage to the lateral line structures of fish, such as the neuromast and its hair cells. Zebrafish (Danio rerio) is recommended as model species to be used in ecotoxicological studies and environmental biomonitoring programs aimed at assessing several biomarkers, such as ototoxicity. However, little is known about the history of and knowledge gaps on zebrafish ototoxicity. Thus, the aim of the current study is to review data available in the scientific literature about using zebrafish as animal model to assess neuromast toxicity. It must be done by analyzing the history and publication category, world production, experimental design, developmental stages, chemical classes, neuromasts and hair cell visualization methods, and zebrafish strains. Based on the results, number, survival and fluorescence intensity of neuromasts, and their hair cells, were the parameters oftentimes used to assess ototoxicity in zebrafish. The wild AB strain was the most used one, and it was followed by Tübingen and transgenic strains with GFP markers. DASPEI was the fluorescent dye most often applied as method to visualize neuromasts, and it was followed by Yo-Pro-1 and GFP transgenic lines. Antibiotics, antitumorals, metals, nanoparticles and plant extracts were the most frequent classes of chemicals used in the analyzed studies. Overall, pollutants can harm zebrafish's mechanosensory system, as well as affect their behavior and survival. Results have shown that zebrafish is a suitable model system to assess ototoxicity induced by environmental pollution.