Ecotoxicological Impact of the Marine Toxin Palytoxin on the Micro-Crustacean Artemia franciscana

Ecotoxicological studies of direct and indirect genotoxicity with Artemia: a integrative review

Artemia is a brine shrimp genus adapted to extreme habitats like ranges salinity from 5-25 g/L and in temperatures from 9 to 35 °C. It is widely distributed and used as an environmental quality biomarker. Artemia franciscana and Artemia salina species are commonly used in ecotoxicological studies and genotoxicity assays due to their short life cycle, high fecundity rate, easy culture, and availability. Thus, considering the importance of these tests in ecotoxicological studies, the present study aimed to present Artemia genus as a biological model in genotoxicity research. To this end, we reviewed the literature, analyzing data published until July 2023 in the Web of Science, SCOPUS, Embase, and PubMed databases. After screening, we selected 34 studies in which the genotoxicity of Artemia for various substances. This review presents the variability of the experimental planning of assays and biomarkers in genotoxicity using Artemia genus as a biological model for ecotoxicological studies and show the possibility of monitoring biochemical alterations and genetic damage effects. Also highlight innovative technologies such as transcriptomic and metabolomic analysis, as well as studies over successive generations to identify changes in DNA and consequently in gene expression.

A review on aquatic toxins - Do we really know it all regarding the environmental risk posed by phytoplankton neurotoxins?

Aquatic toxins are potent natural toxins produced by certain cyanobacteria and marine algae species during harmful cyanobacterial and algal blooms (CyanoHABs and HABs, respectively). These harmful bloom events and the toxins produced during these events are a human and environmental health concern worldwide, with occurrence, frequency and severity of CyanoHABs and HABs being predicted to keep increasing due to ongoing climate change scenarios. These contexts, as well as human health consequences of some toxins produced during bloom events have been thoroughly reviewed before. Conversely, the wider picture that includes the non-human biota in the assessment of noxious effects of toxins is much less covered in the literature and barely covered by review works. Despite direct human exposure to aquatic toxins and related deleterious effects being responsible for the majority of the public attention to the blooms' problematic, it constitutes a very limited fraction of the real environmental risk posed by these toxins. The disruption of ecological and trophic interactions caused by these toxins in the aquatic biota building on deleterious effects they may induce in different species is paramount as a modulator of the overall magnitude of the environmental risk potentially involved, thus necessarily constraining the quality and efficiency of the management strategies that should be placed. In this way, this review aims at updating and consolidating current knowledge regarding the adverse effects of aquatic toxins, attempting to going beyond their main toxicity pathways in human and related models' health, i.e., also focusing on ecologically relevant model organisms. For conciseness and considering the severity in terms of documented human health risks as a reference, we restricted the detailed revision work to neurotoxic cyanotoxins and marine toxins. This comprehensive revision of the systemic effects of aquatic neurotoxins provides a broad overview of the exposure and the hazard that these compounds pose to human and environmental health. Regulatory approaches they are given worldwide, as well as (eco)toxicity data available were hence thoroughly reviewed. Critical research gaps were identified particularly regarding (i) the toxic effects other than those typical of the recognized disease/disorder each toxin causes following acute exposure in humans and also in other biota; and (ii) alternative detection tools capable of being early-warning signals for aquatic toxins occurrence and therefore provide better human and environmental safety insurance. Future directions on aquatic toxins research are discussed in face of the existent knowledge, with particular emphasis on the much-needed development and implementation of effective alternative (eco)toxicological biomarkers for these toxins. The wide-spanning approach followed herein will hopefully stimulate future research more broadly addressing the environmental hazardous potential of aquatic toxins.

Genotoxicity in Artemia spp.: An old model with new sensitive endpoints

Artemia spp. represent models species widely used in ecotoxicological studies due to its simple and fast manipulation in laboratory conditions that makes this crustacean well adaptable to several methodological approaches. Although cysts hatching, swimming behavior, reproductive success and mortality are the main endpoints used for the determination of toxicity, the detection of slight alterations induced by certain substances found at low concentrations in the environment may require more sensitive biomarkers. For this reason, the identification of DNA or chromosomal damages has been proposed as an additional and appreciable endpoint for the ecotoxicological assessment of environmental chemicals. Concerning Artemia models, only few studies indicated that the exposure to organic and inorganic compounds (i.e. pesticides, nanoparticles, bacterial products or heavy metals) can reduce the survival and fitness through the onset of DNA breaks or the dysregulation of key genes. In contrast, literature research revealed a lot of works primarily focusing on the mortality and hatching rates of Artemia nauplii and cysts despite the well-known low sensitivity of these species. The present review reports the current state of knowledge concerning the effects induced by various chemicals, including organic and inorganic compounds, on the common parameters and genotoxicity in both Artemia franciscana and Artemia salina. Advantages and limitations of Artemia spp. models in eco-toxicological investigations together with the most used classes of compounds are briefly discussed. Moreover, a mention is also addressed to scarce availability of literature data focusing on genotoxic effects and the great reliability of molecular approaches observed in this poorly sensitive model organism. Thus, the opportunity to take advantage of genotoxic analyses has also been highlighted, by suggesting this approach as a novel endpoint to be used for the eco-toxicological assessment of several stressors.