key: cord-0067876-4dyulxi8 authors: Oginah, S.A.; Posthuma, L.; Hauschild, M.; Fantke, P. title: Splitting species sensitivity distributions (SSD) to improve accuracy of ecotoxicity results date: 2021-09-24 journal: Toxicol Lett DOI: 10.1016/s0378-4274(21)00666-4 sha: 965b72db0a8c5da6abd106c010c57a734e5ad440 doc_id: 67876 cord_uid: 4dyulxi8 nan cascade of downstream key events (KE), which can result in an adverse outcome, i.e. toxicity. The aryl hydrocarbon receptor (Ahr) and the nuclear receptors (NRs) comprise important MIE targets for environmental pollutants. These receptors are able to bind and be activated by a wide range of xenobiotic chemical compounds, acting as xenosensors, and as transcription factors their modulation may lead to physiological perturbation representing endocrine and metabolic disruption. Knowledge about the specificity and sensitivity of xenosensors in wildlife in general, and in key indicator species in particular, is an important aspect of ecotoxicological research. This knowledge is also the basis for developing receptor-based bioassays for use in environmental monitoring and toxicity testing. The Atlantic cod (Gadus morhua) is a fish species of high importance in pelagic and coastal ecosystems of the North Atlantic, as well as in Norwegian fisheries. It is also a widely used indicator species in environmental monitoring programs in Europe. In the dCod 1.0 project (NFR 2016-2021) we have cloned and characterized the two cod Ahrs as well as a number of cod NRs. For each receptor, we have established a luciferase gene reporter assay (LRA), where single compounds, mixtures, and environmental extracts have been tested. Using this battery of LRAs, we have shown how 11 different bisphenol A (BPA) analogs present similar, and sometimes stronger, endocrine disrupting properties, by activation of the cod Er. Using extracts from sediments representing a gradient of pollution from the inner parts of Byfjorden in Bergen to relatively pristine reference sites, we observe strong receptor activation at the more polluted sites. In the PW-exposed project, we are characterizing the toxicity of produced water from petroleum production using fractionated extracts, pinpointing specific fractions with the highest Ahr activating potency. Together, our results demonstrate that a battery of receptor-based bioassays are useful in environmental monitoring and toxicity testing, at the same time advancing our knowledge of environmental risk from various complex pollution sources. Species sensitivity distributions (SSDs) describe variation in sensitivity of multiple species exposed to a hazardous compound or mixture, as input to ecological risk assessment and deriving environmental quality criteria. Since chemicals have different toxic modes of action (MoA), they affect specific species groups more than others. For example, algae and aquatic plant species are on average more sensitive to exposure to chemicals with herbicidal MoA as compared to other aquatic species groups, such as invertebrates or fish. Current SSDs usually treat all species groups equally and focus on the variation in individual species sensitivities. However, for chemicals with specific MoA, this might lead to underestimation of ecosystem-level sensitivity. We propose to develop SSDs at the level of sensitive species groups versus less-sensitive species groups for chemicals with specific MoA, in order to improve the representativeness of SSDs in terms SARS-CoV-2 infects humans by the use of the extracellular Spike protein (S) to attach to specific cell surface receptors. Due to its indispensable role, the S protein is a major target of virus neutralizing antibodies and has become a key antigen for vaccine candidates development. Recent improvements in mRNA vaccines act to increase protein translation, modulate innate and adaptive immunogenicity and improve delivery. mRNA vaccines are a new type of vaccine to protect against infectious diseases and were the first COVID-19 vaccines authorized worldwide. Relevant animal models are critical for a successful development of all SARS-CoV-2 vaccine candidates and are necessary to characterize the immune response induced by a SARS-CoV-2 vaccine candidate before moving into larger clinical studies, so as to address the theoretical risk for SARS-CoV-2 vaccineinduced disease enhancement. If vaccines are effective on disease severity and reduce hospitalizations, the question is whether vaccination reduces virus transmission. Even, protection against reinfection with SARS-CoV-2 has been observed in rhesus monkeys, who formed neutralising antibodies on initial exposure and a minimum neutralising antibody titre has been proposed, no formals studies have been conducted from a non-clinical or clinical point of view, assessing the effect of the vaccination on a potential reduction in transmission nor the transmission between individuals. This review provides an overview of the non-clinical data of the two different covid-19 RNA vaccines approved on the market, the different animal models studied as well as the virus transmission between individuals. The objective is to make a comparison of the results of the challenge study on Non Human Primates (NHP), analysing all criteria that can approach this activity on the transmission of the infection (i.e. Viral RNA in nasal and oropharyngeal swabs and bronchoalveolar lavage after vaccination, clinical signs, ...) However, since SARS-CoV-2 is a novel pathogen, any surrogate endpoints identified in animal studies would ideally need validation in clinical trials to ensure that they adequately predict efficacy in humans. This abstract has been withdrawn. In the Adverse Outcome Pathway (AOP) concept, the molecular initiating event (MIE) represents the binding of the toxicant to its target, often a receptor inside a cell or on the cellular surface. MIEs lead to a Interestingly that all the tested NPs inhibited microalgal growth at the range of concentrations between 1 and 25 mg/L, and further increase of the concentration ether mitigate the toxic influence or stimulate the growth of microalgae. The highest growth inhibition of both microalgae species (up to 25%) was caused by GQDs after 24 and 96 h of exposure at the concentration of 10 mg/L. GNR inhibited the growth of P. purpureum only at the highest concentrations. SWNTs demonstrated dose and time-dependent growth stimulation of A. ussuriensis (4 times after 7 days compared to control) and dose-dependent growth stimulation of P. purpureum (up to 1.5 times). Among the registered biochemical changes, all the NPs caused membrane depolarization of microalgae. However, only SWCNTs caused dose and time-dependent esterase activity inhibition, which can be caused by metal impurities in this sample. This observation correlates with our previous results [6] . All the tested NPs increased ROS generation in P. purpureum cells. In general, graphene-based NPs demonstrated low toxicity in used microalgae and even stimulated their growth. Registered biochemical alterations varied depend on microalgae species and types of NPs. of ecosystem-level sensitivity. We demonstrate that splitting SSDs into distributions for specific species groups for selected chemicals is feasible, and propose to apply average SSD slopes from data-rich chemicals as proxy SSD slopes for data-poor chemicals. With this approach, we will demonstrate and develop criteria for splitting SSDs, which will complement the current approach of constructing the SSDs for use in environmental protection, assessment, and management of freshwater aquatic ecosystems. Ecotoxicological influence of single-walled carbon nanotubes, graphene nanoribbons, and graphene quantum dots on marine microalgae *K. Pikula The number of modifications of graphene-based nanomaterials is rapidly growing due to their extraordinary electronic, mechanical, optical, and antibacterial properties [1] [2] [3] . The environmental safety assessment of new materials required ecotoxicological bioassays with various endpoints [4, 5] . In this study, we compared the aquatic toxicity of three types of graphene-based nanoparticles (NPs) ( Table 1) in two marine microalgae, namely, Attheya ussuriensis and Porphyridium purpureum. Changes in microalgae cell conditions were measured by flow cytometer CytoFLEX (Beckman Coulter, USA) ( Evaluation of ecotoxicology assessment methods of nanomaterials and their effects Graphene: Insights on Biological, Radiochemical and Ecotoxicological Aspects Antibacterial properties of graphene-based nanomaterials Comparison of the Level and Mechanisms of Toxicity of Carbon Nanotubes, Carbon Nanofibers, and Silicon Nanotubes in Bioassay with Four Marine Microalgae Risk assessments in nanotoxicology: bioinformatics and computational approaches Carbon nanotubeand graphene-based nanomaterials and applications in high-voltage supercapacitor: a review