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Comparison of antioxidant efficiency in the Antarctic notothenchd species, Trematomus bernairchii, Trematomus newnesi and Trematomus hansoni
No full text“Studio degli aspetti forestali ambientali del Fortore-Tammaro-Titerno e vocazione alla produzione del tartufo in ambiente naturale”
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Interactions between trace metals (Cu, Hg, Ni, Pb) and 2,3,7,8- tetrachlorodibenzo-p-dioxin in the antarctic fish trematomus bernacchii: oxidative effects on biotransformation pathway
No full textBiological effects of chemical mixtures are an emerging issue when using biomarkers in field conditions, because
synergistic or inhibitory interactions, cascade, and indirect mechanisms can both enhance or suppress responses to specific classes
of pollutants. The Antarctic rock cod (Trematomus bernacchii) was exposed to various trace metals (Cu, Hg, Ni, and Pb) and to
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), dosed alone or in combination, to generate hypotheses regarding the mechanisms of
action at the cellular level. Concentrations of metals significantly increased in liver of T. bernacchii without significant differences
between organisms exposed only to the elements or cotreated with TCDD. The marked induction of cytochrome P450 (CYP) by
TCDD was greatly suppressed by cotreatment with Cu at both catalytic and protein expression levels, whereas no significant effects
were caused by coexposures with Hg, Ni, and Pb. The oxidative status was measured by integrating individual antioxidants with the
total oxyradical scavenging capacity toward peroxyl radicals (ROO center dot) and hydroxyl radicals (center dot OH). Synergistic
oxidative effects appeared in fish coexposed to Cu and TCDD, suggesting that biotransformation efficiency is down-regulated by
higher levels of hydrogen peroxide, hydroxyl radicals, and/or mechanisms limiting availability of heme groups. Major oxidative
perturbations also were observed in organisms coexposed to TCDD and Hg; in these organisms, however, the marked increase of
glutathione content could explain the absence of oxidative inhibition of the CYP system. More limited oxidative effects were caused
by Ni and Pb, and the contemporary absence of inhibitory effects on CYP would further confirm the importance of pro-oxidant
mechanisms in modulating the biotransformation pathway. The overall results indicate that a wide battery of biomarkers is
necessary to assess the impact of chemical mixtures in field condition
The Use of Tail as a Minimal-Invasive Method to Detect a Large Set of Biochemical Responses in the Italian Wall Lizard Podarcis siculus (Rafinesque, 1810)
Full text linkConventional methods to analyze biochemical processes related to contaminant toxicity usually require the sacrifice of animals to collect tissues and organs. However, for ethical reasons and especially for endangered species, non- or minimal-invasive methods should be preferred. Among vertebrates, reptiles show a general decline worldwide and therefore the use of non- or minimal-invasive methods to measure some biochemical processes in these animals are encouraged. It is well known that most lizards use a common safety behavior implying the natural loss of tail in the case of predation events. Therefore, if common analyses testing contaminant toxicity could be performed in tail tissue, this method, not implying the sacrifice of the animals, could be considered as a good minimal-invasive method. The aim of this study is to test on wild Italian wall lizard Podarcis siculus the use of tail to detect a large set of biomarkers including oxidative stress (TOSCAROO, TOSCAOH, CAT, tGSH, MDA), biotransformation processes (EROD, GSTs) and neurotoxicity (AChE, BChE). All the biochemical responses, excluding EROD and MDA, resulted to be analytically detectable in tail tissues of P. siculus, although the mean values obtained with this minimal-invasive method were significantly lower than those obtained with invasive one
Oxidative and modulatory effects of trace metal on metabolism of polycyclic aromatic hydrocarbons in the antarctic fish Trematomus bernacchii
No full textBiological interactions between various classes of pollutants are of great relevance for the Antarctic marine environment, where the naturally elevated bioavailability of metals like cadmium might indirectly influence sensitivity of endemic organisms toward other environmental pollutants, e.g. polycyclic aromatic hydrocarbons (PAHs). To further investigate reciprocal effects of different chemicals, the fish Trematomus bernacchii was exposed to trace metals (Cd, Cu, Hg, Ni, Pb) and benzo[a]pyrene (BaP, as a model PAH), dosed alone and in combinations. Co-exposures revealed that BaP did not influence the accumulation of metals, while these elements caused significant changes on tissue levels of the PAH. The marked EROD induction caused by BaP was completely suppressed by co-exposure with Cd and Cu, but no effects were observed with Ni, Hg and Pb. Similar results were confirmed at the protein level by Western blot analyses while CYP1A1 mRNA levels were reduced only during Cd co-exposures. Clear evidence of oxidative perturbations was observed in fish co-treated with Cd and BaP and the reduced capability to absorb peroxyl and hydroxyl radicals suggested some oxidative pathways by which this element might indirectly modulate the biotransformation efficiency of Cytochrome P450. Partly different and post-transcriptional mechanisms of action could be hypothesized for Cu, while moderate oxidative effects of Hg, Ni and Pb during co-exposures would confirm their limited influence on metabolism of PAHs. In general, the overall results revealed a complex pathway of interactions between different chemicals during co-exposures and the importance of oxidative status in modulating induction and expression of CYP1A1
Oxidative and modulatory effects of trace metals on metabolism of polycyclic aromatic hydrocarbons in the Anatarctic fish Trematomus bernacchii
No full textSynthesis of vitellogenin (VTG) in male fish is a widely recognized effect for estrogenic pollutants in temperate
environments, while similar investigations are still lacking for Antarctic organisms. In this study, a preliminary characterization of
vitellogenin gene expression was performed by RT-PCR in the key species Trematomus bernacchii sampled in different phases of
reproductive cycle and food availability. Females exhibited the highest gene expression during the spawning period, but VTG
mRNA was always detected also in males; a significant increase of gene expression was observed both in males and females at the
end of the feeding season. These results were not fully supported by a differential exposure to phyto- or anthropogenic estrogens
during the planctonic cycle; on the other side, the endocrine properties of cadmium, naturally elevated in Terra Nova Bay and
increasing during algal bloom, would explain both the presence of VTG mRNA in males and the seasonal changes of gene
induction. Laboratory exposures did not reveal short-term estrogenic effects of cadmium while an elevated responsiveness of T.
bernacchii was observed toward a classical estrogenic receptor agonist (17 beta-estradiol). Different hypotheses were considered
to suggest delayed endocrine effects of cadmium, including the early interaction with other cellular detoxification systems or
alterations at multiple levels of the hypothalamus-pituitary-gonad-liver axis. Although molecular mechanisms of VTG gene
expression in males of T bernacchii remain unclear, obtained results provide interesting insights on this species which should
stimulate future research activitie
Characterization of cytochrome P450 in the Antarctic key sentinel species Trematomus bernacchii.
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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