Dataset Information

Effect of Agitation Method on the Nanosized Degradation of Polystyrene Microplastics Dispersed in Water.

ABSTRACT: Reports of marine organisms ingesting microplastics-formed from large plastic litter drifting in the marine environment by mechanical forces such as waves and photochemical processes initiated by sunlight, particularly ultraviolet rays-are increasing. However, the degradation process from microplastics to nanoplastics that are easily consumed by plankton located in the lower part of the food chain is not clear. Therefore, 200 nm diameter polystyrene (PS) latex particles-nanoparticle tracking analysis (NTA) calibration particles-dispersed in ultrapure deionized water were subjected to three types of agitation: rotation mixing, shaking, and flowing in addition to standing without agitation, and the physical degradation caused by agitation for 1 week at room temperature (23 °C) was evaluated. The degradation of the particles into nanosized particles was assessed by particle size distribution measurement using NTA and shape observation using field emission scanning electron microscopy (FE-SEM). In addition, the ratio of particle aggregation during incubation was calculated from the number of particles present in the region exceeding the particle size distribution range of the monodisperse particles before agitation with respect to the total number of particles. A shape change to a particle size of 100 nm or less was observed for the rotating and flowing of samples, and the influence of aggregation was suppressed to within 21% of the total particles calculated by NTA at the maximum. These results show that chemically stable PS can be degraded from micro- to nanosize with simple agitation in ultrapure deionized water.

SUBMITTER: Mekaru H

PROVIDER: S-EPMC7045318 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature

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Effect of Agitation Method on the Nanosized Degradation of Polystyrene Microplastics Dispersed in Water.

Mekaru Harutaka H

ACS omega 20200211 7

Reports of marine organisms ingesting microplastics-formed from large plastic litter drifting in the marine environment by mechanical forces such as waves and photochemical processes initiated by sunlight, particularly ultraviolet rays-are increasing. However, the degradation process from microplastics to nanoplastics that are easily consumed by plankton located in the lower part of the food chain is not clear. Therefore, 200 nm diameter polystyrene (PS) latex particles-nanoparticle tracking ana ...[more]

PMID: 32118137

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Project description:Plastics are persistent synthetic polymers that accumulate in the marine environment as waste. Microplastic (MP) particles are derived from the breakdown of larger debris or can enter the environment as microscopic fragments. Filter-feeder organisms ingest MP while feeding and are likely to be impacted by MP pollution. To assess the impact of polystyrene microspheres (PS) on the physiology of the Pacific oyster, adult oysters were experimentally exposed to virgin micro-PS (2 and 6 Âµm in diameter; 32 Âµg L-1) for two months during a reproductive cycle. Effects were investigated on transcriptomic responses, in digestive gland gonads and oocytes of exposed oysters. Transcriptomic profiles in the tissues of the exposed oyster showed endocrine disrupting signals, notably highlighting alteration in glucocorticoid response, insulin pathway and fatty-acid metabolism in response to micro-PS exposition. In oocytes from exposed females, several transcripts coding for proteins involved in Ca2+ binding were differentially expressed suggesting a disruption of the Ca2+ signaling pathway with crucial consequences on oocyte maturation. To assess the impact of polystyrene microspheres (PS) on the physiology of the Pacific oyster, adult oysters were experimentally exposed to virgin micro-PS (2 and 6 Âµm in diameter; 32 Âµg L-1) for two months during a reproductive cycle and compared to control oysters. Adults were sampled 2 and 8 weeks after the beginning of exposure (corresponding to T1 and T3, respectively, 8-9 replicates per time of sampling and condition for a total of 56). Tissues were immediately dissected from each oyster, frozen in liquid nitrogen, then crushed to a fine powder at -196Â°C with an oscillating mill mixer and stored in liquid nitrogen until RNA extraction. Oocytes were collected from 5 females per condition, filtered in a 40 Âµm sieve, counted and transferred into 1.5 mL of Extract-all reagent (Eurobio, Courtaboeuf, France) (20,000 oocytes). Total RNA was isolated using 1.5 mL of Extract-all Reagent per 50 mg of gonad powder. For microarray hybridizations, 200 ng of total RNA were indirectly labeled with Cy3 using the Low Input Quick Amp Labeling kit One-Color. Hybridization was performed using the Agilent Gene expression hybridization kit (5188-5242), with 1.65 Î¼g of labeled RNA, for 16 h at 65 Â°C. The employed arrays were Agilent 60-mer 4x44K custom microarrays, containing 31,918 C. gigas ESTs, designed by Dheilly et al. (2011). Slides were scanned on an Agilent Technologies G2565AA Microarray Scanner system at 5 Î¼m resolution, using default parameters. Features were extracted using the Agilent Feature Extraction software 6.1.

Project description:BackgroundPlastic pollution is greatly serious in the ocean and soil. Microplastics (MPs) degraded from plastic has threatened animals and humans health. The accumulation of MPs in the tissues and blood in animals and humans has been found. There is therefore a need to assess the toxicological effects of MPs on the reproductive system.ResultsIn this study, we explored the effect of polystyrene microplastics (PS-MPs) on premature testicular aging in vitro and in vivo. In vitro, we found that testicular sertoli cells (TM4 cells) was prematurely senescent following PS-MPs treatment by the evaluation of a range of aging marker molecules (such as Sa-β-gal, p16 and 21). TM4 cells were then employed for in vitro model to study the potential molecular mechanism by which PS-MPs induce the premature senescence of TM4 cells. NF-κB is identified as a key molecule for PS-MPs-induced TM4 cellular senescence. Furthermore, through eliminating reactive oxygen species (ROS), the activation of nuclear factor kappa B (NF-κB) was blocked in PS-MPs-induced senescent TM4 cells, indicating that ROS triggers NF-κB activation. Next, we analyzed the causes of mitochondrial ROS (mtROS) accumulation induced by PS-MPs, and results showed that Ca2+ overload induced the accumulation of mtROS. Further, PS-MPs exposure inhibits mitophagy, leading to the continuous accumulation of senescent cells. In vivo, 8-week-old C57 mice were used as models to assess the effect of PS-MPs on premature testicular aging. The results illustrated that PS-MPs exposure causes premature aging of testicular tissue by testing aging markers. Additionally, PS-MPs led to oxidative stress and inflammatory response in the testicular tissue.ConclusionIn short, our experimental results revealed that PS-MPs-caused testicular premature aging is dependent on Ca2+/ROS/NF-κB signaling axis. The current study lays the foundation for further exploration of the effects of microplastics on testicular toxicology.

Dataset Information

Effect of Agitation Method on the Nanosized Degradation of Polystyrene Microplastics Dispersed in Water.

Publications

Effect of Agitation Method on the Nanosized Degradation of Polystyrene Microplastics Dispersed in Water.

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