Metal bioaccumulation and metallothionein (MT) expression were investigated in the gills and liver of the red-blooded Antarctic teleost Trematomus hansoni to evaluate the possibility for this species to face, with adequate physiological responses, an increase of copper and cadmium concentrations in its tissues. Specimens of this Antarctic fish were collected from Terra Nova Bay (Ross Sea) and used for a metal exposure experiment in controlled laboratory conditions. The two treatments led to a significant accumulation of both metals and increased gene transcription only for the MT-1. The biosynthesis of MTs was verified especially in specimens exposed to Cd, but most of these proteins were soon oxidized, probably because they were involved in cell protection against oxidative stress risk by scavenging reactive oxygen species. The obtained data highlighted the phenotypic plasticity of T. hansoni, a species that evolved in an environment characterized by naturally high concentrations of Cu and Cd, and maybe the possibility for the Antarctic fish to face the challenges of a world that is becoming more toxic every day.
In recent decades, the interest in PFAS has grown exponentially around the world, due to the toxic effects induced by these chemical compounds in humans, as well as in other animals and plants. However, current knowledge related to the antistress responses that organisms can express when exposed to these substances is still insufficient and, therefore, requires further investigation. The present study focuses on antioxidant responses in Squalius cephalus and Padogobius bonelli, exposed to significant levels of PFAS in an area of the Veneto Region subjected to a recent relevant pollution case. These two ubiquitous freshwater species were sampled in three rivers characterised by different concentrations of PFAS. Several biomarkers of oxidative stress were evaluated, and the results suggest that PFAS chronic exposure induces some physiological responses in the target species, at both cellular and tissue scales. The risk of oxidative stress seems to be kept under control by the antioxidant system by means of gene activation at the mitochondrial level. Moreover, the histological analysis suggests an interesting protective mechanism against damage to the protein component based on lipid vacuolisation.
The study aimed at investigating the effectiveness of teaching Biology at primary school by playing and using a laboratory approach, in a limited-resources learning environment with additional restrictive rules due to the current pandemic emergency. It also investigated the possibility of dealing with Microbiology topics, such as microorganisms and their role in human life. These topics are traditionally not taught at primary school, particularly at third grade.The research process was based on the hypothesis that the adopted methodology may be useful to foster the active co-construction of knowledge and to increase the pleasure in learning. It makes pupils the main subjects of their learning process, with positive impacts on interest towards Science and on building an active citizenship.First of all, an online survey about Science, Microbiology and Health Education teaching was supplied. The sample consisted of teachers and parents of the school in which the research was carried out and of the Venice province. Then, a test about foreknowledge and interest towards Science and microorganisms was submitted to students. Outcomes were analysed in order to identify the experimental and the control group among two primary school third grade classes in a town of the Venice province.The experimental group was tested with activities characterized by the application of the scientific method and the learner-centred approach, engaging from an emotional, sensory and playful point of view. The control group was, instead, tested with a traditional and teacher-centred approach.Tests and ongoing observation data supported the possibility of teaching Microbiology topics using both the approaches. The laboratory approach was more successful than the traditional one in knowledge acquisition but that is a subtle difference. The effectiveness was more significant in: developing interest towards Science and microorganisms, implementing inclusion and enhancing participation, promoting pleasure in learning and limiting negative feelings linked to the topics.
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