Molecular techniques for investigating toxic dinoflagellate species in the western English Channel, UK and in Bahrain coastal waters of the Arabian Gulf

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Single and Combined Toxicity Effects of Zinc Oxide Nanoparticles: Uptake and Accumulation in Marine Microalgae, Toxicity Mechanisms, and Their Fate in the Marine Environment

Recently, there has been rapid growth in the production of zinc oxide nanoparticles (ZnO-NPs) due to their applications in household and cosmetic products. Over the last decade, considerable research was conducted to reveal the effect of ZnO-NPs on microalgae, which form the base of the aquatic food chain. This review discusses the fate and behavior of ZnO-NPs in the marine environment. Predominately, the toxicity mechanism of ZnO-NPs on marine microalgae could be attributed to three sources: the release of Zn2+ ions; the interaction between ZnO-NPs and algae cells; and the generation of reactive oxygen species (ROS). Most toxicity studies were carried out using single ZnO-NPs under conditions not often observed in natural ecosystems; however, organisms including microalgae are more likely exposed to ZnO-NPs mixed with other types of pollutants. This review highlights the importance of increasing the assessment studies of combined pollutants. Lastly, knowledge, research, gaps, and opportunities for further research in this field are presented

Influence of graphene oxide on the toxicity of polystyrene nanoplastics to the marine microalgae Picochlorum sp.

International audienceGraphene oxide (GO) features distinctive physical and chemical characteristics; therefore, it has been intensively investigated in environmental remediation as a promising material for clean-up of soil contamination and water purification and used as immobilization material. Plastic is a widespread pollutant, and its breakdown products such as nanoplastics (NPs) should be evaluated for potential harmful effects. This study is aimed to evaluate the influence of GO on the toxicity of polystyrene (PS) NPs to the marine microalgae Picochlorum sp. over a period of 4 weeks. The capability of GO to reduce the toxic effects of PS NPs was assessed through investigating exposure sequence of GO in the presence of 20 nm diameter-sized polystyrene NPs. This was accomplished through five test groups: microalgae pre-exposed to GO prior to incubation with PS NPs, microalgae post-exposed to GO after incubation with PS NPs, microalgae simultaneously exposed to GO and PS NPs, and individual exposure of microalgae to either GO or PS NPs. Cytotoxicity assay results demonstrated that microalgae pre-exposed to GO prior to incubation with PS NPs showed an increased viability and chlorophyll a content. The pre-exposure to GO has reduced the growth inhibition rate (IR) from 50%, for microalgae simultaneously exposed to GO and PS NPs, to 26%, for microalgae pre-exposed to GO. Moreover, the lowest level of reactive oxygen species (ROS) was recorded for microalgae exposed to GO only and microalgae pre-exposed to GO. Fourier-transform infrared (FTIR) analysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) observations revealed some morphological changes of both algae and their extracellular polymeric substances (EPS) upon GO and PS NPs exposure combinations. The sequence of GO exposure to aquatic microorganisms might affect the level of harm caused by the PS NPs. Therefore, application of GO as part of an immobilization material and in the removal of pollutants from water should be carefully investigated using different pollutants and aquatic organisms

Graphene Oxide (GO) Materials—Applications and Toxicity on Living Organisms and Environment

Graphene-based materials have attracted much attention due to their fascinating properties such as hydrophilicity, high dispersion in aqueous media, robust size, high biocompatibility, and surface functionalization ability due to the presence of functional groups and interactions with biomolecules such as proteins and nucleic acid. Modified methods were developed for safe, direct, inexpensive, and eco-friendly synthesis. However, toxicity to the environment and animal health has been reported, raising concerns about their utilization. This review focuses primarily on the synthesis methods of graphene-based materials already developed and the unique properties that make them so interesting for different applications. Different applications are presented and discussed with particular emphasis on biological fields. Furthermore, antimicrobial potential and the factors that affect this activity are reviewed. Finally, questions related to toxicity to the environment and living organisms are revised by highlighting factors that may interfere with it

Toxicity Effect of Silver Nanoparticles on Photosynthetic Pigment Content, Growth, ROS Production and Ultrastructural Changes of Microalgae Chlorella vulgaris

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