Impact of Microbial Colonization of Polystyrene Microbeads on the Toxicological Responses in the Sea Urchin Paracentrotus lividus

Abstract

The sea urchin Paracentrotus lividus (P. lividus) was exposed to either virgin or biofilm-covered polystyrene microbeads (micro-PS, 45 μm) in order to test the effect of microbial colonization on the uptake, biodistribution, and immune response. The biofilm was dominated by bacteria, as detected by scanning electron microscopy and 16S rRNA sequencing. A higher internalization rate of colonized micro-PS inside sea urchins compared to virgin ones was detected, suggesting a role of the plastisphere in the interaction. Colonized and virgin micro-PS showed the same biodistribution pattern by accumulating mainly in the digestive system with higher levels and faster egestion rates for the colonized. However, a significant increase of catalase and total antioxidant activity was observed only in the digestive system of colonized micro-PS-exposed individuals. Colonized micro-PS also induced a significant decrease in the number of coelomocytes with a significant increase in vibratile cells, compared to control and virgin micro-PS-exposed animals. Moreover, a general time-dependent increase in the red/white amoebocytes ratio and reactive oxygen species and a decrease in nitrogen ones were observed upon exposure to both colonized and virgin micro-PS. Overall, micro-PS colonization clearly affected the uptake and toxicological responses of the Mediterranean sea urchin P. lividus in comparison to virgin micro-PS.

Sequestration of Polystyrene Microplastics by Jellyfish Mucus

“…Importantly, there was no increase of background fluorescence observed that could be attributed to a potential dye leakage, thus validating our experimental approach. This is in line with other similar leakage control experiments, where a negligible dye leakage was observed even after 48 h (Murano et al, 2021).…”

Nanoplastics in Aquatic Environments: Impacts on Aquatic Species and Interactions with Environmental Factors and Pollutants

“…The identical but virgin PMMA-MPs caused no physiological changes in the organisms [110]. PS-MPs (45 µm) coated with bacterial biofilm also accumulated at a faster rate in exposed sea urchins than virgin PS-MPs, causing greater egestion rates, decreased immune cell counts, changes in the antioxidant system, and increased generation of reactive oxygen and nitrogen species [111]. In another study under laboratory conditions, the inclusion of a real-world environmental biofilm enhanced detritivorous amphipods' shredding rate of high-density polyethylene (HDPE) plastics (1 cm); however, it was unclear if the shredded particles were rejected or eaten by the organisms [112].…”

Ovothiol ensures the correct developmental programme of the sea urchin Paracentrotus lividus embryo

“…Embryonic development represents an extremely sensitive and delicate stage of life for all living organisms, especially for those with external fertilization, such as sea urchins. Indeed, in the marine ecosystem, sea urchin adults and embryos are constantly exposed to a variety of environmental pressures, including both intrinsic and extrinsic/anthropogenic factors causing oxidative and nitrosative stress [1][2][3][4][5][6][7]. Nevertheless, they have acquired the ability, to some extent, to maintain homeostasis in an adverse environment, through the evolution of a 'chemical defensome', an integrated network of gene families and pathways, involved in the protection and repair from damage [8].…”