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1. Neurotoxicity and Oxidative Stress Development in Adult Atya lanipes Shrimp Exposed to Titanium Dioxide Nanoparticles

   https://doi.org/10.3390/toxics11080694  

   Cruz-Rosa, Stefani; Pérez-Reyes, Omar (August 2023, Toxics)

   Titanium dioxide is a type of nanoparticle that is composed of one titanium atom and two oxygen atoms. One of its physicochemical activities is photolysis, which produces different reactive oxygen species (ROS). Atya lanipes shrimp affect detrital processing and illustrate the potential importance of diversity and nutrient availability to the rest of the food web. It is essential in removing sediments, which have an important role in preventing eutrophication. This study aimed to determine the toxic effect of changes in behavior and levels of oxidative stress due to exposure to titanium dioxide nanoparticles in Atya lanipes and to determine the effective concentration (EC50) for behavioral variables. The concentrations of TiO2 NPs tested were 0.0, 0.50, 1.0, 2.0, and 3.0 mg/L with the positive controls given 100 µg/L of titanium and 3.0 mg/L of TiO2 NPs ± 100 µg/L of titanium. After 24 h of exposure, significant hypoactivity was documented. The EC50 was determined to be a concentration of 0.14 mg/L. After the exposure to 10 mg/L of TiO2 NPs, oxidative stress in gastrointestinal and nervous tissues was documented. The toxic effects of this emerging aquatic pollutant in acute exposure conditions were characterized by sublethal effects such as behavior changes and oxidative stress. 

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2. Enhanced toxicity of environmentally transformed ZnO nanoparticles relative to Zn ions in the epibenthic amphipod Hyalella azteca

   https://doi.org/10.1039/C8EN00755A  

   Poynton, Helen C.; Chen, Chun; Alexander, Shaun L.; Major, Kaley M.; Blalock, Bonnie J.; Unrine, Jason M. (January 2019, Environmental Science: Nano)

   After release into the aquatic environment, engineered nanomaterials (ENMs) undergo complex chemical and physical transformations that alter their environmental fate and toxicity to aquatic organisms. Hyalella azteca are sediment-dwelling amphipods predicted to have a high exposure level to ENMs and have previously shown to be highly sensitive to ZnO nanoparticles (NPs). To investigate the impacts of environmentally transformed ZnO NPs and determine the route of uptake for these particles, we exposed H. azteca to ZnSO 4 , ZnO NPs, and environmental aged ZnO NPs which resulted in three types of particles: 30 nm ZnO–Zn 3 (PO 4 ) 2 core–shell structures (p8-ZnO NPs), micron scale hopeite-like phase Zn 3 (PO 4 ) 2 ·4H 2 O (p6-ZnO NPs), and ZnS nano-clusters (s-ZnO NPs). Treatments included freshwater, saltwater (3 ppt), and the presence of sediment, with a final treatment where animals were contained within mesh baskets to prevent burrowing in the sediment. Dissolution was close to 100% for the pristine ZnO NPs and phosphate transformed NPs, while s-ZnO NPs resulted in only 20% dissolution in the water only exposures. In the freshwater exposure, the pristine and phosphate transformed ZnO NPs were more toxic (LC 50 values 0.11–0.18 mg L −1 ) than ZnSO 4 (LC 50 = 0.26 mg L −1 ) and the s-ZnO NPs (LC 50 = 0.29 mg L −1 ). Saltwater treatments reduced the toxicity of ZnSO 4 and all the ZnO NPs. In the presence of sediment, water column concentrations of Zn were reduced to 10% nominal concentrations and toxicity in the sediment with basket treatment was similarly reduced by a factor of 10. Toxicity was further reduced in the sediment only treatments where the sediments appeared to provide a refuge for H. azteca . In addition, particle specific differences in toxicity were less apparent in the presence of sediment. Bioaccumulation was similar across the different Zn exposures, but decreased with reduced toxicity in the saltwater and sediment treatments. Overall, the results suggest that H. azteca is exposed to ZnO NPs through the water column and NP transformations in the presence of phosphate do not reduce their toxicity. Sulfidized ZnO NPs have reduced toxicity, but their similar level of bioaccumulation in H. azteca suggests that trophic transfer of these particles will occur. 

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3. Fluorogenic Reaction Probes Defect Sites on Titanium Dioxide Nanoparticles

   Zuo, Li; Hossain, Mohammad Akter; Dubadi, Rabindra; Kist, Madelyn M.; Farhana, Fatiha; Chen, Jiao; Jaroniec, Mietek; Shen, Hao (May 2024, ChemNanoMat)

   Charlotte Liu (Ed.)

   Titanium dioxide nanoparticles (TiO2 NPs) have traditionally been utilized as industrial catalysts, finding widespread application in various chemical processes due to their exceptional stability and minimal toxicity. However, quantitatively assessing the reactive sites on TiO2 NPs remains a challenge. In this study, we employed a fluorogenic reaction to probe the apparent reactivity of TiO2 NPs. By manipulating the number of defect sites through control of hydrolysis speed and annealing temperature, we determined that the Ti(Ⅲ) content is positively correlated with the reactivity of TiO2 NPs. Additionally, these Ti(Ⅲ) sites could be introduced by reducing commercial TiO2 NPs using NaBH4. Our findings suggest that fluorogenic oxidation of Amplex Red is an effective method for probing defect site densities on TiO2 NPs. Utilizing single-molecule fluorescence imaging, we demonstrated the ability to map defect site density within TiO2 nanowires. Achieving sub-nanoparticle spatial resolution, we observed significant intraparticle and interparticle variations in the defect site distribution, leading to substantial reactivity heterogeneity. 

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4. A novel larval diet interacts with nutritional stress to modify juvenile behaviors and glucocorticoid responses

   https://doi.org/10.1002/ece3.7860  

   Ledón‐Rettig, Cristina C.; Lagon, Sarah R. (July 2021, Ecology and Evolution)

   Abstract Developmental plasticity can allow the exploitation of alternative diets. While such flexibility during early life is often adaptive, it can leave a legacy in later life that alters the overall health and fitness of an individual. Species of the spadefoot toad genusSpeaare uniquely poised to address such carryover effects because their larvae can consume drastically different diets: their ancestral diet of detritus or a derived shrimp diet. Here, we useSpeabombifronsto assess the effects of developmental plasticity in response to larval diet type and nutritional stress on juvenile behaviors and stress axis reactivity. We find that, in an open‐field assay, juveniles fed shrimp as larvae have longer latencies to move, avoid prey items more often, and have poorer prey‐capture abilities. While juveniles fed shrimp as larvae are more exploratory, this effect disappears if they also experienced a temporary nutritional stressor during early life. The larval shrimp diet additionally impairs juvenile jumping performance. Finally, larvae that were fed shrimp under normal nutritional conditions produce juveniles with higher overall glucocorticoid levels, and larvae that were fed shrimp and experienced a temporary nutritional stressor produce juveniles with higher stress‐induced glucocorticoid levels. Thus, while it has been demonstrated that consuming the novel, alternative diet can be adaptive for larvae in nature, doing so has marked effects on juvenile phenotypes that may recalibrate an individual's overall fitness. Given that organisms often utilize diverse diets in nature, our study underscores the importance of considering how diet type interacts with early‐life nutritional adversity to influence subsequent life stages. 

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5. Nanoscale Interactions: Evaluating the Ecotoxicity of Engineered Nanoparticles on the Dynamics of Commercially Important Microalgal Strains

   Louime, Clifford J.; Diaz-Vazquez, Liz M.; Perez, Abner; Torres Díaz, Marielys.; Rojas-Perez, Arnulfo; Vázquez López, Juan C.; Davilla Aguer, Catalina; Malca Reyes, Carlos A. (January 2020, International journal of science and engineering investigations)

   null (Ed.)

   Society has long been exposed to naturally-occurring nanoparticles. Due to their ubiquitous nature, biological systems have adapted and built protection against their potential effects. However, for the past decades, there have been onslaughts of newly engineered nanoparticles being released in the environment with no known effects on ecosystems. Although these materials offer distinct advantages in manufacturing processes, such as odor-free fabric or controlled drug delivery, their fate in nature has yet to be thoroughly investigated. As the size of an already-large NPs market is expected to grow, due to advances in synthetic biology, it is vital that we increase our understanding of their impacts on human, food and natural ecosystems. Recent studies have shown that NPs affect phytoplankton biomass and diversity in the ocean, solely by regulating micronutrients bioavailability. These types of changes could ultimately impact several biogeochemical cycles, as phytoplankton are responsible for almost half of the primary production on earth. Consequently, this study was designed to evaluate the impact of various concentrations (0μM, 20μM, 40μM, 80μM and 100μM) of several manufactured nanoparticles (gold, carbon and iron) on the dynamics of four economically important microalgae strains. Responses, such as chlorophyll content, protein, lipid content, lipid profile, biomass and cell morphology were monitored over a period of two weeks. No significant acute toxicity was exhibited within the first 24 hours of exposure. However, after 4 days, a remarkably high mortality rate was detected with increasing NPs concentrations of Fe60, C80 and Au60. Iron suspensions were found to be more toxic to the microalgae strains tested than those of Gold and Carbon under comparable regimes. Further investigations with other, either positively or negatively charged nanoparticles, should provide a deeper understanding on the impacts on these engineered materials in our ecosystems. 

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