Impact of nano-sized plastic on the nutritional value and gut microbiota of whiteleg shrimp Litopenaeus vannamei via dietary exposure

Effect of microplastics on oxytetracycline trophic transfer: Immune, gut microbiota and antibiotic resistance gene responses

Microplastics and antibiotics are prevalent and emerging pollutants in aquatic ecosystems, but their interactions in aquatic food chains remain largely unexplored. This study investigated the impact of polypropylene microplastics (PP-MPs) on oxytetracycline (OTC) trophic transfer from the shrimp (Neocaridina denticulate) to crucian carp (Carassius auratus) by metagenomic sequencing. The carrier effects of PP-MPs promoted OTC bioaccumulation and trophic transfer, which exacerbated enterocyte vacuolation and hepatocyte eosinophilic necrosis. PP-MPs enhanced the inhibitory effect of OTC on intestinal lysozyme activities and complement C3 levels in shrimp and fish, and hepatic immunoglobulin M levels in fish (p < 0.05). Co-exposure of MPs and OTC markedly increased the abundance of Actinobacteria in shrimp and Firmicutes in fish, which caused disturbances in carbohydrate, amino acid, and energy metabolism. Moreover, OTC exacerbated the enrichment of antibiotic resistance genes (ARGs) in aquatic animals, and PP-MPs significantly increased the diversity and abundance of ARGs and facilitated the trophic transfer of teta and tetm. Our findings disclosed the impacts of PP-MPs on the mechanism of antibiotic toxicity in aquatic food chains and emphasized the importance of gut microbiota for ARGs trophic transfer, which contributed to a deeper understanding of potential risks posed by complex pollutants on aquatic ecosystems.

Effect of Ball-Milling Treatment Combined with Glycosylation on the Structure and Functional Properties of Litopenaeus vannamei Protein

Litopenaeus vannamei protein (LVP) is a high-quality protein. However, its functional properties do not fully meet the needs of food processing. In this study, LVP-xylose conjugates were prepared by conventional wet heat method (GLVP) and ball-milling-assisted wet heat method (GBLVP), respectively. The changes in structure and functional properties of the glycosylated LVP were explored. The findings revealed that ball-milling pretreatment increased the grafting degree to 35.21%. GBLVP had a sparser surface structure and lower particle size than GLVP. FTIR spectra showed that xylose was grafted onto LVP successfully and GBLVP had the lowest α-helix content. Compared with GLVP, GBLVP had a decrease in intrinsic fluorescence intensity and surface hydrophobicity, and an increase in UV absorption intensity. Moreover, GBLVP had higher foaming capacity, solubility and water-holding capacity, and lower allergenicity than GLVP. However, ball-milling pretreatment had a negative impact on the vitro digestibility and oil-holding capacity of GBLVP. In conclusion, ball-milling-assisted treatment of glycosylation could effectively improve the functional properties of LVP, benefiting the broader application of LVP in the food industry.

Trophic transfer and interfacial impacts of micro(nano)plastics and per-and polyfluoroalkyl substances in the environment

Both micro(nano)plastics (MNPs) and per-and polyfluoroalkyl substances (PFAS) possessed excellent properties and diverse applications, albeit gained worldwide attention due to their anthropogenic, ubiquitous, degradation resistant nature and a wide variety of ecological and human health impacts. MNPs and PFAS discharged from discrete sources and extensively bioaccumulated in the food chain through trophic transfer and their long-distance transport potential assist in their dispersal to pristine but vulnerable ecosystems such as Antarctica. They inevitably interacted with each other in the environment through polarized N-H bond, hydrogen bond, hydrophobic interaction, and weak bond energies such as Van der Waals, electrostatic, and intramolecular forces. During co-exposure, they significantly impact the uptake and bioaccumulation of each other in exposed organisms, which may increase or decrease their bioavailable concentration. Hence, this review compiles the studies on the co-occurrence and adsorption of PFAS and MNPs in the environment, their trophic transfer, combined in vivo and in vitro impacts, and factors influencing the MNP-PFAS interface. A significant proportion of studies were conducted in China, Europe, and the US, while studies are rare from other parts of the world. Freshwater and marine food chains were more prominently investigated for trophic transfers compared to terrestrial food chains. The most notable in vivo effects were growth and reproductive impairment, oxidative stress, neurotoxicity and apoptosis, DNA damage, genotoxicity and immunological responses, behavioral and gut microbiota modifications, and histopathological alterations. Cellular uptake of PFAS and MNPs can impact cell survival and proliferation, photosynthesis and membrane integrity, ROS generation and antioxidant responses, and extracellular polymeric substances (EPS) release in vitro. MNP characteristics, PFAS properties, tissue and species-dependent distribution, and environmental medium properties were the main factors influencing the PFAS and MNP nexus and associated impacts. Last but not least, gaps and future research directions were highlighted to better understand the interplay between these critical persistent chemicals.

Organ-specific distribution and size-dependent toxicity of polystyrene nanoplastics in Australian bass (Macquaria novemaculeata)

Micro- and nano-plastics (MNPs) are emerging contaminants found in air, water, and food. Ageing and weathering processes convert aquatic plastics into MNPs which, due to their small size, can be assimilated by organisms. The accumulation of MNPs in aquatic life (e.g., fish, oysters, and crabs) will, in turn, pose risks to the health of ecosystems and human. This study focuses on the uptake, biodistribution, and size-dependent toxicity of polystyrene nano-plastics (PS-NPs) in a commercially important food web, the Australian Bass (Macquaria novemaculeata). Fish were fed artemia containing PS-NPs of various sizes (ranging from 50 nm to 1 μm) for durations of 5 and 7 days. The findings revealed that smaller NPs (50 nm) accumulated in the brain and muscle tissues at higher concentrations, whereas larger NPs (1 μm) were primarily found in the gills and intestines. In addition, an inverse correlation was observed between the size of NPs and the rate of trophic transfer, with smaller PS-NPs resulting in a higher transfer rate from artemia to fish. Polystyrene NPs caused both activation of the enzyme superoxide dismutase and damage to the DNA of fish tissues. These effects were size dependent. Metabolomic analysis revealed that indirect exposure to different-sized PS-NPs resulted in altered metabolic profiles within fish intestines, potentially impacting lipid and energy metabolism. These results offer novel perspectives on the size-specific toxic impacts of NPs on fish and the transfer of plastics through the food chain.

Transgenerational adaptation to ocean acidification determines the susceptibility of filter-feeding rotifers to nanoplastics

The adaptation of marine organisms to the impending challenges presented by ocean acidification (OA) is essential for their future survival, and mechanisms underlying OA adaptation have been reported in several marine organisms. In the natural environment, however, marine organisms are often exposed to a combination of environmental stressors, and the interactions between adaptive responses have yet to be elucidated. Here, we investigated the susceptibility of filter-feeding rotifers to short-term (ST) and long-term (LT) (≥180 generations) high CO2 conditions coupled with nanoplastic (NPs) exposure (ST+ and LT+). Adaptation of rotifers to elevated CO2 caused differences in ingestion and accumulation of NPs, resulting in a significantly different mode of action on in vivo endpoints between the ST+ and LT+ groups. Moreover, microRNA-mediated epigenetic regulation was strongly correlated with the varied adaptive responses between the ST+ and LT+ groups, revealing novel regulatory targets and pathways. Our results indicate that pre-exposure history to increased CO2 levels is an important factor in the susceptibility of rotifers to NPs.

Effects of nanoplastics on the gut microbiota of Pacific white shrimp Litopenaeus vannamei

Nanoplastics (NPs) are an abundant, long-lasting, and widespread type of environmental pollution that is of increasing concern because of the serious threats they might pose to ecosystems and species. Identifying the ecological effects of plastic pollution requires understanding the effects of NPs on aquatic organisms. Here, we used the Pacific white shrimp (Litopenaeus vannamei) as a model species to investigate whether ingestion of polystyrene NPs affects gut microbes and leads to metabolic changes in L. vannamei. The abundance of Proteobacteria increased and that of Bacteroidota decreased after NPs treatment. Specifically, Vibrio spp., photobacterium spp., Xanthomarina spp., and Acinetobacter spp. increased in abundance, whereas Sulfitobacter spp. and Pseudoalteromonas spp. decreased. Histological observations showed that L. vannamei exposed to NP displayed a significantly lower intestinal fold height and damaged intestinal structures compared with the control group. Exposure to NPs also stimulated alkaline phosphatase, lysozyme, and acid phosphatase activity, resulting in an immune response in L. vannamei. In addition, the content of triglycerides, total cholesterol, and glucose were significantly altered after NP exposure. These results provided significant ecotoxicological data that can be used to better understand the biological fate and effects of NPs in L. vannamei.

Polystyrene nanoplastics induce lipid metabolism disorder and alter fatty acid composition in the hepatopancreas of Pacific whiteleg shrimp (Litopenaeus vannamei)

The impact of nanoplastics (NPs) on environmental pollution and aquatic organisms has gradually attracted attention, but there are relatively few reports of the effects of NPs on the lipid metabolism of crustaceans. In this study, we exposed Pacific whiteleg shrimp (Litopenaeus vannamei) to different concentrations of polystyrene NPs (0, 0.1, 1, 5, and 10 mg/L) for 28 days. We then evaluated the effects of NP exposure on metabolite content, histology, lipid metabolism-related enzyme activity, and gene expression. Our results showed that with increasing NPs concentrations and exposure time, (1) the crude protein and crude fat content decreased and fatty acid composition changed; (2) the tissue structure was destroyed and the number of lipid droplets increased in the hepatopancreas; (3) the activities of acetyl-CoA carboxylase, fatty acid synthase, carnitine palmitoyl transferase-1, pyruvate kinase and low-density lipoprotein content tended to decrease and that of lipase and high-density lipoprotein content first increased and then decreased; the content of triglycerides and total carbohydrate first decreased and then increased; (4) the expression of fatty acid synthesis-related genes (Fas, SREBP, and FAD), fatty acid transport-related genes (FATP, FABP, and ACBP), and fatty acid decomposition-related genes (Ampk and lip1) first increased and then decreased. These results indicate that exposure to NPs can cause physiological disorders of fat metabolism in L.vannamei and that high concentrations of NPs have a negative impact on lipid metabolism. These results of this study provide valuable ecotoxicological data for better interpretation of the mechanism of action of NPs in crustaceans.

A comprehensive review of micro- and nano-plastics in the atmosphere: Occurrence, fate, toxicity, and strategies for risk reduction

Micro- and nano-plastics (MNPs) have received considerable attention over the past 10 years due to their environmental prevalence and potential toxic effects. With the increase in global plastic production and disposal, MNP pollution has become a topic of emerging concern. In this review, we describe MNPs in the atmospheric environment, and potential toxicological effects of exposure to MNPs. Studies have reported the occurrence of MNPs in outdoor and indoor air at concentrations ranging from 0.0065 items m-3 to 1583 items m-3. Findings have identified plastic fragments, fibers, and films in sizes predominantly <1000 μm with polyamide (PA), polyester (PES), polyethylene terephthalate (PET), polypropylene (PP), rayon, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polyacrylonitrile (PAN), and ethyl vinyl acetate (EVA) as the major compounds. Exposure through indoor air and dust is an important pathway for humans. Airborne MNPs pose health risks to plants, animals, and humans. Atmospheric MNPs can enter organism bodies via inhalation and subsequent deposition in the lungs, which triggers inflammation and other adverse health effects. MNPs could be eliminated through source reduction, policy/regulation, environmental awareness and education, biodegradable materials, bioremediation, and efficient air-filtration systems. To achieve a sustainable society, it is crucial to implement effective strategies for reducing the usage of single-use plastics (SUPs). Further, governments play a pivotal role in addressing the pressing issue of MNPs pollution and must establish viable solutions to tackle this significant challenge.

Synergistic adverse effects of microfibers and freshwater acidification on host-microbiota interactions in the water flea Daphnia magna

Microfibers are the most common type of microplastics in freshwater environments. Anthropogenic climate stressors, such as freshwater acidification (FA), can interact with plastic pollution to disrupt freshwater ecosystems. However, the underlying mechanisms responsible for the interactive effects of microfibers and FA on aquatic organisms remain poorly understood. In this study, we investigated individual Daphnia magna-microbiota interactions affected by interactions between microfibers and FA (MFA). We found that the accumulated amount of microfibers in pH-treatment groups was significantly higher than in the control groups, resulting in negative consequences on reproduction, growth, and sex ratio. We also observed that MFA interactions induced immunity- and reproduction-related biological processes. In particular, the abundance of pathogenic bacteria increased only in MFA groups, indicating that MFA interactions can cause intestinal damage. Our integrated analysis of microbiomes and host transcriptomes revealed that synergistic adverse effects of MFAs are closely related to changes in microbial communities, suggesting that D. magna fitness and the microbial community are causally linked. These finding may help elucidate the toxicity mechanisms governing the responses of D. magna to microfibers and acidification interactions, and to host-microbiome-environment interactions.

Effect of PET microplastics on the growth, digestive enzymes, and intestinal flora of the sea cucumber Apostichopus japonicus

Marine microplastic (MP) pollution is becoming a serious problem and their potentially toxic effects on marine organisms have attracted much attention. Sea cucumber is very important for the safety and health of marine ecosystems. However, there have been relatively few studies on the effects of microplastic pollution on sea cucumbers at environmentally-related concentrations and under controlled conditions. Therefore, this study evaluated the effects of polyethylene terephthalate (PET) microplastics (particle sizes: 0.5-45 μm, 2-200 μm, and 20-300 μm; and three concentration levels for each particle size, approximately 103, 104, and 105 particles/kg) on the basic biological indicators, intestinal digestive enzymes, and intestinal flora of Apostichopus japonicus after a 28-day feeding experiment. This study showed that environmentally-related and high concentrations of microplastics had little effect on A. japonicus. This study provides valuable reference information about the effects of marine microplastic pollution on sea cucumbers.

Microplastics in feed cause sublethal changes in the intestinal microbiota and a non-specific immune response indicator of the freshwater crayfish Procambarus clarkii (Decapoda: Cambaridae)

Microplastics (MP) are a hazardous pollutant of global concern that threatens aquatic ecosystems and public health. We used the invasive, cosmopolitan, and environmentally versatile red swamp crayfish Procambarus clarkii as a model to study the effects of MP on the intestinal microbiome. Crayfish collected from the environment were compared with specimens exposed to recycled Polyethylene terephthalate (rPET) MP in feed (30%) for 96 h in the laboratory and a control group. We analyzed the 16S rRNA of the intestinal bacteria by PCR-DGGE and high-throughput sequencing. MP exposure caused dysbiosis of the intestinal microbiota, with an increase in Alphaproteobacteria and Actinobacteria. We detected higher abundance of opportunistic genera such as Klebsiella, Acinetobacter, Hydromonas, Pseudomonas, Gemmobacter, and Enterobacter on MP fed organisms. Moreover, MP exposure reduced the abundance of Clostridia and Bateroidetes, which are important for immune system development and pathogen prevention. Furthermore, MP exposure decreased the phenoloxidase (PO) immune response in crayfish. There was a significant difference in the richness of intestinal bacterial communities after consumption of food contaminated with MP, likely increasing the abundance of opportunistic bacteria in the intestinal microbiota. Our results suggest that MP alter the gut microbial composition and impair the health of P. clarkii.

Occurrence and spatial distribution of microplastic contaminated with heavy metals in a tropical river: Effect of land use and population density

Microplastics are of concern due to their potential environmental risks. This research aims to find the effect of land use (agriculture, urban, and aquaculture) and population density on the abundance of microplastics contaminated with heavy metals in surface water and sediment of the Chao Phraya River in Thailand. Results indicated that population density is directly correlated with increased microplastic abundance. Most microplastics were found in the urban zone (water: 80 ± 38 items/m³ and sediment: 62 ± 11 items/kg) and were small fragments (0.05 to 0.3 mm). Polymer types of polypropylene and polyethylene were commonly found. Heavy metals of Cr, Cu, Cd, Pb, Zn, Ni, and Ti were detected in microplastics in water and sediment, with Cu, Pb, and Zn being the most dominant. Heavy metals in microplastics were highest in the agriculture zone. In general, the presence of metals on microplastics may potentially impact the ecosystem and human health.

Progress on the Effects of Microplastics on Aquatic Crustaceans: A Review

It is impossible to overlook the effects of microplastics on aquatic life as they continuously accumulate in aquatic environments. Aquatic crustaceans, as both predator and prey, play an important role in the food web and energy transmission. It is of great practical significance to pay attention to the toxic effects of microplastics on aquatic crustaceans. This review finds that most studies have shown that microplastics negatively affect the life history, behaviors and physiological functions of aquatic crustaceans under experimental conditions. The effects of microplastics of different sizes, shapes or types on aquatic crustaceans are different. Generally, smaller microplastics have more negative effects on aquatic crustaceans. Irregular microplastics have more negative effects on aquatic crustaceans than regular microplastics. When microplastics co-exist with other contaminants, they have a greater negative impact on aquatic crustaceans than single contaminants. This review contributes to rapidly understanding the effects of microplastics on aquatic crustaceans, providing a basic framework for the ecological threat of microplastics to aquatic crustaceans.

Sublethal Biochemical Effects of Polyethylene Microplastics and TBBPA in Experimentally Exposed Freshwater Shrimp Palaemonetes argentinus

The biochemical effects of sublethal exposure to polyethylene microplastics (PEM) of 40–48 µm particle size and the flame retardant tetrabromobisphenol A (TBBPA), a plastic additive, on the freshwater shrimp Palaemonetes argentinus were assessed. Here, we postulate that the use of enzyme and thyroid hormones as biomarkers contributes to the knowledge of the effects of microplastics and plastic additives on freshwater crustaceans. To address this, we evaluated the activities of acetylcholinesterase (AChE), glutathione S-transferase (GST), and carboxilesterase (CbE, using 1-naphthyl acetate (NA) as substrate) and levels of the thyroid hormones thyroxine (T4) and triiodothyronine (T3) after shrimp were exposed (for 96 h) to these xenobiotics at environmentally realistic concentrations. The results showed that the mixture of both xenobiotics led to a decrease in AChE and GST activities and increased T4 levels. We suggest that physiological processes could be compromised in freshwater organisms when exposed to microplastics and TBBPA together, and this could ultimately affect upper levels of the food web.

Toxic effects of glyphosate on histopathology and intestinal microflora of juvenile Litopenaeus vannamei

Glyphosate is a widely used broad-spectrum herbicide, its pollution to the surrounding conditions can't be ignored. It has been reported that glyphosate has poisonous impacts on aquatic animals. In this study, juvenile Litopenaeus vannamei (L. vannamei) was exposed to glyphosate, and the lethal concentration 50 (LC₅₀) of glyphosate to juvenile L. vannamei for 48 h was 47.6 mg/L. The histological analysis for intestine and hepatopancreas and the intestinal microorganisms of L. vannamei were evaluated after 48 h of exposure to glyphosate with LC₅₀. The histological analysis results showed that the lumen of hepatic tubules was diffused and deformed, the hepatic tubules were ruptured and intestinal villi were fallen off seriously after exposure to glyphosate for 48 h Moreover, the intestinal microbial composition and structure of L. vannamei were changed, with the abundance of Alphaproteobacteria increased significantly. The abundance of Rhodobacteraceae, Vibrio and Legionella increased, but there was no significant difference. The abundance of Bacillus, Paraburkholderia, Enhydrobacter, Comamonas and Alkanindiges decreased significantly. However, the homeostasis of intestinal microorganisms was destroyed. Phenotypic prediction of the two groups of microorganisms revealed a significant increase in the abundance of Facultatively Anaerobic in the glyphosate challenged group. This study suggested that hepatopancreas and intestinal tissue of L. vannamei were seriously damaged after 48 h of exposure to glyphosate with LC₅₀, and intestinal microbial homeostasis was disrupted.

Alterations of gut and oral microbiota in the individuals consuming take-away food in disposable plastic containers

Microplastics (MP) and nanoplastics (NP) exist in the disposable plastic take-away containers. This study aims to determine the gut and oral microbiota alterations in the individuals frequently and occasionally consuming take-away food in disposable plastic containers (TFDPC), and explore the effect of micro/nanoplastics (MNP) reduction on gut microbiota in mice. TFDPC consumption are associated with greater presences of gastrointestinal dysfunction and cough. Both occasional and frequent consumers have altered gut and oral microbiota, and their gut diversity and evenness are greater than those of non-TFDPC consuming cohort. Multiple gut and oral bacteria are associated with TFDPC consumers, among which intestinal Collinsella and oral Thiobacillus are most associated with the frequent consumers, while intestinal Faecalibacterium is most associated with the occasional consumers. Although some gut bacteria associated with the mice treated with 500 µg NP and 500 µg MP are decreased in the mice treated with 200 µg NP, the gut microbiota of the three MNP groups are all different from the control group. This study demonstrates that TFDPC induces gut and oral microbiota alterations in the consumers, and partial reduction of the size and amount of MNP cannot rectify the MNP-induced gut microbial dysbiosis.

MPs and NPs intake and heavy metals accumulation in tissues of Palinurus elephas (J.C. Fabricius, 1787), from NW Aegean sea, Greece

European marine waters are infested with plastic, with an average density of 1 plastic item in every four square-meters. Research relevant to MPs-NPs ingestion by wild decapods in European waters is limited, none of which regards the European spiny lobster. Totally 4102 plastic particles were extracted from the spiny lobster stomach tissues of both sexes. Out of the 63 samples analysed only three (4.8%) of them were found with no plastic particles. The range of number of MPs in stomachs was from 20 to 273 MPs individual^-1. The 98.3% were fragments. In total 3833 plastic particles were extracted from the gill tissues of both sexes. MPs were found in all samples (n = 50),99.2% of the detected particles were fragments. The MPs detected in gills ranged from 11 to 339 MPs individual^-1. The DLS method was used in order to evaluate the NPs presence. Nanoplastics were detected in 22.6% of stomachs and in the 48.1% of gills. A total of 43 polymer types were identified in both tissues. Also, our study assessed the accumulation of heavy metals at the edible tail muscle. Certain elements were detected above the EU's Maximum Residue Level, including arsenic. The present results are alarming and the potential human health implications could be serious.

Detection of microplastic fibers tangle in deep-water rose shrimp (Parapenaeus longirostris, Lucas, 1846) in the northeastern Mediterranean Sea

Microplastic (MP) pollution in marine environments has been a major global concern in recent years. Microplastic particles pose a threat in aquatic animals by accumulating in their digestive system, acting like a pollution vector, and they can also transfer to upper trophic levels. For that reason, commercially important deep-water rose shrimp Parapenaeus longirostris were employed in this study to examine the MP pollution status of two different regions (Samandağ and Mersin offshore waters) of the northeastern Mediterranean Sea. MPs were detected in all examined specimens (average of 18.8 MPs ind-1), and fiber tangle-shaped like balls were observed by 22% and 9% at Samandağ and Mersin, respectively. P. longirostris individuals from Samandağ showed higher occurrence (100%) and higher accumulation (29.7 ± 24.4 MPs ind-1). MP abundance extracted from the shrimp individuals from Samandağ region was higher than that of previously reported shrimp species. The majority of extracted microplastics were fiber (100%), black (46%) in color and 1-2.5 mm in size. Polyethylene was identified as the most common polymer type by Fourier transform infrared spectroscopy (FTIR). This study is the first report to evaluate microplastic occurrence and fiber tangles in P. longirostris from northeastern Mediterranean Sea. Results obtained in this study will enhance the understanding of MP pollution among different trophic levels.

The Influence of Photodynamic Antimicrobial Chemotherapy on the Microbiome, Neuroendocrine and Immune System of Crustacean Post Larvae

Photodynamic antimicrobial chemotherapy (PACT), employing a combination of light and natural photosensitizer molecules such as curcumin, has been accepted as a safe modality for removing aquatic pathogens which cause diseases such as cholera in humans and vibriosis in aquatic animals. Curcumin and its photodegradation products are generally considered as safe to animals, but the impact of reactive oxygen species (ROS) generated by these products on the growth and survival of organisms at a cellular level has not been studied in detail. The ROS generated by curcumin on photoexcitation using blue light (λ_max 405 nm, 10 mW cm^-2) disinfects more than 80% of free-living Vibrio spp. in the rearing water of Penaeus monodon. However, it is less effective against Vibrio spp. colonized inside P. monodon because the carapace of the animal prevents the transmission of more than 70% of light at the 400-450 nm range and thus reduces the formation of ROS. The influence of curcumin and photoexcited curcumin on the microbiome of P. monodon were revealed by nanopore sequencing. The photoexcited curcumin induced irregular expression of genes coding the moult-inhibiting hormone (MIH), Crustacean hyperglycaemic hormone (CHH)), prophenoloxidase (ProPO), and crustin, which indicates toxic effects of ROS generated by photoexcited curcumin on the neuroendocrine and immune systems of crustaceans, which could alter their growth and survival in aquaculture settings. The study proposed the cautious use of photodynamic therapy in aquaculture systems, and care must be taken to avoid photoexcitation when animals are experiencing moulting or environmental stress.

Is Wild Marine Biota Affected by Microplastics?

The present review provides detailed information on the adverse effects of MPs on wild marine organisms, including tissue damage, fish condition, oxidative stress, immune toxicity, and genotoxicity. A bibliometric analysis was carried out on CiteSpace (version 6.1.R3) (Drexel University, Philadelphia, PA, USA) to verify how many papers studied the effects on wild marine species. The results showed a total of 395 articles, but only 22 really presented data on the effects or impacts on marine biota, and of these, only 12 articles highlighted negative effects. This review shows that the observed effects in wild organisms were less severe and milder than those found in the experimental conditions. The knowledge of negative effects caused by direct ingestion of microplastics in wild animals is still limited; more efforts are necessary to fully understand the role of MPs and the adverse effects on wild marine organisms, the ecosystem, and human health.

Magnetic resonance imaging for non-invasive measurement of plastic ingestion in marine wildlife

Monitoring plastic ingestion by marine wildlife is important for both characterizing the extent of plastic pollution in the environment and understanding its effect on species and ecosystems. Current methods to detect plastic in the digestive system of animals are slow and invasive, such that the number of animals that can be screened is limited. In this article, magnetic resonance imaging (MRI) is investigated as a possible technology to perform rapid, non-invasive detection of plastic ingestion. Standard MRI methods were able to directly measure one type of plastic in a fulmar stomach and another type was able to be indirectly detected. In addition to MRI, other standard nuclear magnetic resonance (NMR) measurements were made. Different types of plastic were tested, and distinctive NMR signal characteristics were found in common for each type, allowing them to be distinguished from one another. The NMR results indicate specialized MRI sequences could be used to directly image several types of plastic. Although current commercial MRI technology is not suitable for field use, existing single-sided MRI research systems could be adapted for use outside the laboratory and become an important tool for future monitoring of wild animals.

Investigating the effects of microplastic ingestion in Scyliorhinus canicula from the South of Sicily

Plastic pollution is increasing dramatically worldwide, causing adverse effects on a wide variety of marine organisms at all trophic levels. As predators, sharks play a key role in marine ecosystems and they could especially be threatened by the ingestion of microplastics. This study contributes to expand the existing data on the MPs ingestion by a Mediterranean elasmobranch species, Scyliorhinus canicula, adding new information on the potential impact that this class of contaminants can have on the metabolism of this ecologically relevant species. The present research is aimed: i) to assess if the ingestion of MPs in S. canicula is related to sex, size and depth of catch; ii) to evaluate the effect of MPs on fish body condition; iii) to evaluate if the ingested MPs influence the amino acid and fatty acid composition of eye and liver. A total of 61 specimens of S. canicula were analysed. Forty-nine individuals (80.3 %) had ingested plastic items. Totally, 147 plastic elements were found, mainly belonging to small MPs (49 %), and large MPs (46 %), mostly represented by fibers (84 %). The predominant colour was black. No differences were found between sex and size. A difference in the number of items/specimens related to the deep, highest between 50 and 100 m (4.4), while the lowest between 101 and 500 m (2.1) was found. The condition factor (Kn) value was equal to 1.00 highlighting the wellness of the fish. Arginine (20.1 %), Glutamate (17.4), Phenylalanine (15.7 %), Proline (15.6 %) and were the most abundant amino acids in the eyes of S. canicula. The relative fatty acid composition of the livers was dominated by fatty acids SA (30.2 %) (SFA), CA (29.9 %) (SFA) and OA (22.4 %) (MUFA). This paper reports a study on the relationship between amino acids and fatty acids composition and ingested MPs, highlighting that no significant effects were found.

Toxicokinetics and toxicodynamics of plastic and metallic nanoparticles: A comparative study in shrimp

Nanoplastic is recognized as an emerging environmental pollutant due to the anticipated ubiquitous distribution, increasing concentration in the ocean, and potential adverse health effects. While our understanding of the ecological impacts of nanoplastics is still limited, we benefit from relatively rich toxicological studies on other nanoparticles such as nano metal oxides. However, the similarity and difference in the toxicokinetic and toxicodynamic aspects of plastic and metallic nanoparticles remain largely unknown. In this study, juvenile Pacific white shrimp Litopenaeus vannamei was exposed to two types of nanoparticles at environmentally relative low and high concentrations, i.e., 100 nm polystyrene nanoplastics (nano-PS) and titanium dioxide nanoparticles (nano-TiO₂) via dietary exposure for 28 days. The systematic toxicological evaluation aimed to quantitatively compare the accumulation, excretion, and toxic effects of nano-PS and nano-TiO₂. Our results demonstrated that both nanoparticles were ingested by L. vannamei with lower egestion of nano-TiO₂ than nano-PS. Both nanoparticles inhibited the growth of shrimps, damaged tissue structures of the intestine and hepatopancreas, disrupted expression of immune-related genes, and induced intestinal microbiota dysbiosis. Nano-PS exposure caused proliferative cells in the intestinal tissue, and the disturbance to the intestinal microbes was also more serious than that of nano-TiO₂. The results indicated that the effect of nano-PS on the intestinal tissue of L. vannamei was more severe than that of nano-TiO₂ with the same particle size. The study provides new theoretical basis of the similarity and differences of their toxicity, and highlights the current lack of knowledge on various aspects of absorption, distribution, metabolism, and excretion (ADME) pathways of nanoplastics.

Trophic transfer of nanoplastics through a microalgae-crustacean-small yellow croaker food chain: Inhibition of digestive enzyme activity in fish

This study investigated the effects of nanoplastics on marine organisms via trophic transfer in the food chain. We designed a three-step food chain comprising microalga (Dunaliella salina), small crustaceans (Artemia franciscana), and fish (small yellow croakers; Larimichthys polyactis) and evaluated the effects of trophic transfer in marine organisms, as well as verified the possibility of nanoplastic transfer to humans via trophic transfer. Using amine-modified nanopolystyrene (nPS-NH₂) as a pollutant, we conducted both direct-exposure and trophic transfer experiments to determine how pollutants move through the food chain (D. salina → A. franciscana). Exposure of D. salina to nPS-NH₂, which was adsorbed on its cell wall, resulted in transfer to A. franciscana with alteration of gut permeability. Additionally, assessment of the adverse effects of nPS-NH₂ via a dietary pathway (three-step food chain) on the L. polyactis digestive system revealed that nanoplastics adsorbed to the cell wall of microalgae are gradually transferred to higher trophic level organisms, such as via food resources consumed by humans, inducing the inhibition of digestive enzyme activity (α-amylase). It indicates that human could eventually be exposed to nanoplastics and experience toxicity.

Polystyrene nanoparticles aggravate the adverse effects of di-(2-ethylhexyl) phthalate on different segments of intestine in mice

Emerging evidence indicates that nanoplastics (NPs) can transport organic pollutants such as di-(2-ethylhexyl) phthalate (DEHP) into organisms and induce adverse health effects. Nevertheless, the toxic effects of NPs combined with DEHP on mammalian intestine are still unclear. In this study, the C57BL6J mice were exposed to polystyrene nanoparticles (PSNPs), DEHP or them both for 30 days to determine their effects on different segments of intestine and the gut microbiota. As a result, DEHP alone or co-exposure to DEHP and PSNPs induced histological damages in all intestinal parts, mainly manifested as the decreased villus lengths, increased crypt depths in the duodenum, jejunum and ileum and decreased villus counts accompanied with decreased epithelial area in the colon. Moreover, decreased mucus coverage, down-regulated Muc2 expression levels as well as the broken tight junctions were observed in intestinal epithelium of mice, particularly obvious in the co-treatment groups. In general, as manifested by greater alterations in most of the parameters mentioned above, simultaneously exposed to PSNPs and DEHP seemed to induce enhanced toxic effects on intestine of mouse when compared with DEHP alone. Furthermore, the altered community composition of gut microbiota might at least partially contribute to these abnormalities. Overall, our results highlight the aggravated toxicity on different segments of intestine in mammalians due to co-exposure of PSNPs and DEHP, and these findings will provide valuable insights into the health risk of NPs and plastic additives.

Occurrence of microplastics in gastrointestinal tract of fish from the Gulf of Guinea, Ghana

Over the past decades, there has been a growing concern about microplastics pollution in global aquatic habitats and its potential impact on human health. This study was carried out to determine the presence of microplastics in fish of economic importance in Ghana. Microplastics were found to be abundant in all investigated samples, with 68 % of the fishes contaminated with microplastics and a total of 133 plastic items identified in the fish. The presence of fibers, black coloured particles, and microplastics in the size range of 0.5-1.0 mm was the most abundant in the samples examined. Three polymers specifically, polyethylene, polyvinyl acetate, and polyamide were identified in the study. The presence of microplastics in the fishes investigated may pose severe ecological and health concerns, and hence comprehensive policies targeted at preventing plastic pollution of Ghana's maritime environment is warranted.

Investigation of microplastic contamination in blood cockles and green mussels from selected aquaculture farms and markets in Thailand

Recent studies have indicated that bivalves are bioindicators for microplastic pollution since they are filter feeders and accumulate microplastics (MPs) during their feeding process. This study focused on the investigation of MPs in blood cockles (Tegillarca granosa) and green mussels (Perna viridis) from selected aquaculture farms and markets in Thailand. The abundance of MPs was identified by fluorescence microscopy with Nile Red tagging and the polymer detection by micro-Fourier Transform Infrared Spectroscopy (micro-FTIR). The number of MPs in blood cockle samples from the Khlong Dan market and the BangBo aquaculture farm was 11 ± 5 and 6 ± 1 particles/individual, respectively. For green mussel samples, the number of MPs from the Talaad Thai market and the Sriracha fisheries research station was 96 ± 19 and 11 ± 7 particles/individual, respectively. The results of the study indicate that the number of MPs in bivalve samples from the markets is much higher than in the aquaculture farms. This probably is due to the contamination of MPs in bivalves during the packaging and transportation processes. However, further studies are needed to confirm this. The predominant MPs were fragments and fibres with a size range of 0.05-0.3 mm. Most polymers were polypropylene, polyethylene, copolymer, polyester, and nylon. In brief, this study showed the contamination of MPs in bivalves cultivated for human consumption. The accumulation of MPs in these marine bivalves can lead to the biomagnification of MPs along the food chain. This can impact food safety and human health.

Toxicological impacts of micro(nano)plastics in the benthic environment

Micro(nano)plastics (MNPs) have sparked growing public and scientific concerns as emerging pollutants in recent decades, due to their small size and potential for significant ecological and human health impacts. Understanding the toxicological effects of MNPs on aquatic organisms is of great importance; however, most of the available research on aquatic organisms has focused on the pelagic organisms, and studies on benthic organisms are lacking yet. Being bottom-dwelling creatures, benthos perhaps confronts more extreme pressure from MNPs. Therefore, this review summarizes the current literature on the impacts of MNPs on benthic organisms to reveal their toxicity on the survival, growth, development and reproductive systems. MNPs can accumulate in various tissues of benthos and probably cause tissue-specific damage, resulting in genotoxicity and reproductive toxicity to benthic organisms. And, in severe cases, they may also pass on the adverse effects to the next generations. The complexity of co-exposure to MNPs with other aquatic contaminants is also highlighted. Furthermore, we have comprehensively discussed the internal and external factors affecting the toxicity of MNPs in benthic organisms. Additionally, we also presented the current research gaps and potential future challenges, providing overall background information for a thorough understanding of the toxic effects of MNPs in the benthic aquatic ecosystem.

Microplastics in decapod crustaceans: Accumulation, toxicity and impacts, a review

The presence of microplastics in the aquatic environment poses a serious threat not only to aquatic organisms but also to human beings that consume them. The uptake and effects of microplastics have been studied in almost all groups of aquatic organisms. This review details the different aspects of microplastics exposure in an ecologically and economically important group of crustaceans, the Decapods. A majority of Decapod crustaceans such as prawns, shrimp, crabs, lobsters and crayfish are consumed as seafood and play important roles in food chains and food webs. Numerous studies are available on the accumulation of microplastics in tissues such as the gills, hepatopancreas and gastrointestinal tract in these organisms. Experimental studies have also highlighted the toxic effects of microplastics such as oxidative stress, immunotoxicity and reproductive and developmental toxicity in them. This review also summarizes the ecological impacts and implications in human beings as well as lacunae with regard to microplastic uptake in Decapods.

An overview of the effects of nanoplastics on marine organisms

The ubiquity and detrimental effects of plastics in the environment have become global environmental concerns over the past decade. Intensive anthropogenic activities, such as urbanisation, industrialisation and increasing population density, have resulted in increased plastic pollution in the environment. Recently, nanoplastics have received increased research attention and concern because of their potential adverse effects on marine organisms. However, the potential ecological issues associated with nanoplastics are not yet fully understood because of the insufficient and limited research conducted to date on baseline data, exposure and associated risks for marine organisms. This review highlights an understanding of the nature and characteristics of nanoplastics, as well as the occurrence of nanoplastics in the marine environment. In the future, the effects of nanoplastics on marine organisms may directly or indirectly influence human health. Thus, this review also highlights the effects of nanoplastics on marine organisms. An overview and insights into the occurrence of nanoplastics in marine environments and their potential effects on marine organisms will facilitate the preventative interventions and measures of nanoplastics pollution in the marine environment.

Is There Evidence of Health Risks From Exposure to Micro- and Nanoplastics in Foods?

The human health impact of exposure to micro (MP) and nanoplastics (NP) from food remains unknown. There are several gaps in knowledge that prevent a complete risk assessment of them. First, the fact that some plastics may be chemically harmful, either directly toxic themselves or because they absorb and carry other components, which makes these particles may possess 3 types of hazards, physical, chemical and biological. In addition, the levels at which toxic effects may occur are unknown and there is a lack of studies to estimate the levels to which we are exposed. Plastic particles can induce physical stress and damage, apoptosis, necrosis, inflammation, oxidative stress and immune responses, which could contribute to the development of diseases such as cancer, metabolic disorders, and neurodevelopmental conditions, among others. In addition, they may have effects on other pathologies that have not yet been studied, such as food allergy, where they could act modifying the digestibility of food allergens, increasing intestinal permeability, promoting an intestinal inflammatory environment or causing intestinal dysbiosis, which could promote food allergen sensitization. However, given the limited information on the presence of MP and especially NP in food, further research is needed to estimate whether they could amplify the risk of allergic sensitization to food proteins and to elucidate the risk to human health.

Effects of Acute Exposure to Polystyrene Nanoplastics on the Channel Catfish Larvae: Insights From Energy Metabolism and Transcriptomic Analysis

Microplastics (nanoplastics) pollution has been a major ecological issue threatening global aquatic ecosystems. However, knowledge of the adverse effects of nanoplastics and the effects on freshwater ecosystems is still limited. To understand the impacts of nanoplastics on freshwater ecosystems, it is essential to reveal the physiological changes caused by nanoplastics in freshwater organisms, especially at their early life-history stages. In the present study, the larval channel catfish Ietalurus punetaus were exposed to gradient concentrations (0, 5, 10, 25, and 50 mg/L) of 75-nm polystyrene nanoplastics (PS-NPs) for 24 h or 48 h, and changes in contents of energy metabolites, metabolic enzyme activities and transcriptome were assessed. The results showed that glucose and triglyceride contents increased after 24 h of exposure to 10 or 25 mg/L of PS-NPs but decreased with increased concentrations or prolonged exposure duration. Activities of most metabolic enzymes analyzed decreased in the larvae after 48 h of exposure, especially in 25 or 50 mg/L of PS-NPs. These suggested that PS-NPs caused huge energy consumption and disturbed the energy metabolism in larval fish. Transcriptomic analysis showed that 48 h of exposure to 50 mg/L PS-NPs affected the expression of genes involved in protein digestion and induced response of proteasomes or heat shock proteins in the larval I. punetaus. The genes involved in peroxisome proliferator-activated receptors (PPAR) pathway and biosynthesis of amino acids were activated after the exposure. PS-NPs also depressed the expression of the genes involved in gonad development or muscle contraction in the larval I. punetaus. Overall, acute exposure to 75-nm PS-NPs disrupted the energy metabolism by consuming the energy reserves, and affected a series of molecular pathways which may further affect the development and survival of fish. This study provided the information about adverse effects of nanoplastics on the fish larvae and revealed the molecular pathways for the potential adverse outcomes.

Microbiome: A forgotten target of environmental micro(nano)plastics?

Microplastics (MPs) and nanoplastics (NPs) are emerging pollutants in different environmental compartments (air, soil and water) and that may induce several ecotoxicological effects on organisms and their microbiota. A considerable number of studies has been addressing and highlighting the effects of MPs/NPs on biochemical, molecular and behavior effects of aquatic organisms. However, less attention has been focused on microbiota. Here, a critical overview of published studies focusing on microorganisms affected by MPs and NPs after in vitro or in vivo exposure is provided. Available studies regarding the properties of MPs/NPs, microbial phyla, experimental conditions, techniques employed, and effects are summarized. The link between microbiota disruption and other effects on other hosts (e.g., crustaceans, fish, and mammals) as also analyzed. Overall, the literature review shows that most studies with microorganisms were performed in vitro (MPs: 44.11%; NPs: 23.52%) in comparison with in vivo tests (MPs: 32.35%; NPs: 11.76%). The most studied MP/NPs were polystyrene particles, generally spheres, with sizes <50 μm and concentrations ranged between 100 and 1000 mg L^-1. The most studied main phyla were Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. MPs/NPs induced microbiome composition disruption, immune response (i.e., immune modulator release, immune cells activation and inflammatory response), enzyme activity changes (i.e., catalase, urease, dehydrogenase, alkaline phosphatase, and fluorescein diacetate hydrolase) and gene expression changes. The immune responses changes were related to microbiome disruption. Research gaps are highlighted and recommendations for future research indicated that microbiome is sensitive to MP/NPs and microbiome disruption can be a valuable tool to assess the risk of plastic particles to human and environmental health.

Potential toxicity of nanoplastics to fish and aquatic invertebrates: Current understanding, mechanistic interpretation, and meta-analysis

Nanoplastics (NPs) are widely detected in aquatic ecosystems and attracting considerable attention. Although ecotoxicological impacts of NPs on aquatic biota are increasingly identified, the extent and magnitude of these detrimental effects on fish and aquatic invertebrates still lack systematic quantification and mechanistic interpretation. Here, the toxicity, influencing factors, and related mechanisms of NPs to fish and aquatic invertebrates are critically reviewed and summarized based on a total of 634 biological endpoints through a meta-analysis, where five vital response categories including growth, consumption, reproduction, survival, and behavior were emphasized to elucidate the negative impacts of NPs to fish and aquatic invertebrates from physiological to molecular levels. Our results revealed that NPs significantly decreased the survival, behavior, and reproduction of fish and/or aquatic invertebrates by 56.1%, 24.2%, and 36.0%, respectively. NPs exposure increased the oxidative stress and oxidative damage by 72.0% and 9.6%, respectively; while significantly decreased antioxidant prevention system and neurotransmission by 24.4% and 15.9%, respectively. Also, the effects of particle size, functional group, and concentration range of NPs on the physiological and biochemical reactions in the living organisms were discussed. This information is helpful to more accurately understanding the underlying toxic mechanisms of NPs to aquatic biota and guiding future studies.

Key knowledge gaps for One Health approach to mitigate nanoplastic risks

There are increasing concerns over the threat of nanoplastics to environmental and human health. However, multidisciplinary barriers persist between the communities assessing the risks to environmental and human health. As a result, the hazards and risks of nanoplastics remain uncertain. Here, we identify key knowledge gaps by evaluating the exposure of nanoplastics in the environment, assessing their bio-nano interactions, and examining their potential risks to humans and the environment. We suggest considering nanoplastics a complex and dynamic mixture of polymers, additives, and contaminants, with interconnected risks to environmental and human health. We call for comprehensive integration of One Health approach to produce robust multidisciplinary evidence to nanoplastics threats at the planetary level. Although there are many challenges, this holistic approach incorporates the relevance of environmental exposure and multi-sectoral responses, which provide the opportunity to identify the risk mitigation strategies of nanoplastics to build resilient health systems.

A systematic review on the effects of nanomaterials on gut microbiota

•

Nanomaterials have been shown to affect gut microbiota (GM) both in vivo and in vitro.

•

The effects have been shown to depend on size, dose, dose duration and functional groups.

•

In general, more studies seem to indicate dose-dependent adverse effects of NMs towards GM.

•

Standardized protocols are needed for characterization of NMs, dosing, and test systems (both in vitro and in vivo).

Some nanomaterials (NMs) have been shown to possess antimicrobial activity and cause GM dysbiosis. Since NMs are being used widely, a systematic assessment of the effects of NMs on GM is warranted. In this systematic review, a total of 46 in vivo and 22 in vitro studies were retrieved from databases and search engines including Science-Direct, Pubmed and Google scholar. Criteria for assessment of studies included use of in vitro or in vivo studies, characterization of NMs, use of single or multiple doses as well as consistency of results. GM dysbiosis has been studied most widely on TiO₂, Ag, Zn-based NMs. There was moderate evidence for GM dysbiosis caused by Zn- and Cu-based NMs, Cu-loaded chitosan NPs and Ag NMs, and anatase TiO₂ NPs, as well as low evidence for SWCNTs, nanocellulose, SiO₂, Se, nanoplastics, CeO_2, MoO₃ and graphene-based NMs. Most studies indicate adverse effects of NMs towards GM. However, more work is required to elucidate the differences on the reported effects of NM by type and sex of organisms, size, shape and surface properties of NMs as well as effects of exposure to mixtures of NMs. For consistency and better agreement among studies on GM dysbiosis, there is need for internationally agreed protocols on, inter alia, characterization of NMs, dosing (amounts, frequency and duration), use of sonication, test systems (both in vitro and in vivo), including oxygen levels for in vitro models.

Sub-acute exposure to nanoplastics via two-chain trophic transfer: From brine shrimp Artemia franciscana to small yellow croaker Larimichthys polyactis

This study investigated the trophic transfer of nanoplastics in marine food chains. We fed nanoplastic-exposed Artemia franciscana (brine shrimp) to Larimichthys polyactis (small yellow croaker) daily for eight days. Subsequently, the overall health condition, histopathological damage to the liver and digestive tract, and swimming ability of the fish were measured. After the sub-acute exposure to nanoplastics via trophic transfer, the fish showed inhibited growth, severe liver damage, as well as a poorer swimming ability compared to the control. The swimming ability was especially affected, in terms of the overall movement as well as thigmotaxis. The results thus clarified that even an indirect exposure to nanoplastics could induce neurotoxic effects and affect the swimming ability of the fish. As fish are well-known human food resources, the possibility of such trophic transfers affecting higher trophic level organisms, such as humans, cannot be ruled out.

Are your shoes safe for the environment? - Toxicity screening of leachates from microplastic fragments of shoe soles using freshwater organisms

This study investigated the toxic effects of leachates from microplastic fragments of soles from four different types of shoes (slippers, trekking shoes, running shoes, and sneakers) on three aquatic organisms (Chlamydomonas reinhardtii, Daphnia magna, and Danio rerio). The chemical components in each leachate were identified; furthermore, chlorophyll a contents of C. reinhardtii were measured, and immobilization of D. magna and deformities in D. rerio were observed. The abnormalities observed in the test species exposed to the leachates were compared and chemical compounds majorly influencing the species were determined by principal component analysis (PCA). Sneaker leachate showed growth inhibitions in C. reinhardtii, immobility and mortality in D. magna, and severe abnormalities in D. rerio. Consequently, aquatic toxicity was majorly associated with benzothiazole, carbon disulfide, ethyl acetate, and p-xylene. The results showed that toxic chemicals could leach from load-originated microplastics when exposed to aquatic media, and consequently, induce significant negative effects on aquatic organisms. Since microplastics from shoe soles discharge the above-mentioned toxic chemicals, regulating the chemical use during plastic production is critical to prevent severe effects of microplastic toxicity in aquatic organisms, and to maintain the health of aquatic environments.

Micro/nano-plastics cause neurobehavioral toxicity in discus fish (Symphysodon aequifasciatus): Insight from brain-gut-microbiota axis

Numerous studies have investigated neurobehavioral toxicity of microplastics, but no studies have illustrated mechanism via brain-gut axis. Here, juvenile discus fish (Symphysodon aequifasciatus) were exposed for 96 h to microfibers (900 µm, fiber, MFs) or nanoplastics (~88 nm, bead, NPs) with three concentrations (0, 20 and 200 µg/L). Accumulation in fish gut was independent of plastics type and concentration. MFs reduced growth performance while NPs weakened swimming and predatory performance of post-exposed discus. For brain cholinesterase activity, acetylcholinesterase was activated by NPs while NPs/MFs exposure inhibited butyrylcholinesterase. Concentrations of neurotransmitters (acetylcholine, dopamine and γ-aminobutyric acid) increased in brain but decreased in gut after NPs or MFs exposure. For gut microbiota, increased richness under MFs exposure was observed. At phylum level, Proteobacteria proportion was lower in NPs but higher in MFs. Abundance of Clostridia and Fusobacteriia (Bacillus), potentially secreting neurotransmitters, increased in NPs but decreased in MFs. Brain transcriptomics revealed seven upregulated and four downregulated genes concerning neural-activities. Pathways of neuroactive ligand-receptor interaction and serotonergic synapse were enriched in both MFs and NPs, but dopaminergic synapse pathway was enriched only in MFs. These results established a novel mechanism by which microplastics might cause behavioral toxicities via brain-gut-microbiota axis.

Impact of nanomaterials on the intestinal mucosal barrier and its application in treating intestinal diseases

The intestinal mucosal barrier (IMB) is one of the important barriers to prevent harmful substances and pathogens from entering the body environment and to maintain intestinal homeostasis. The dysfunction of the IMB is associated with intestinal diseases and disorders. Nanomaterials have been widely used in medicine and as drug carriers due to their large specific surface area, strong adsorbability, and good biocompatibility. In this review, we comprehensively discuss the impact of typical nanomaterials on the IMB and summarize the treatment of intestinal diseases by using nanomaterials. The effects of nanomaterials on the IMB are mainly influenced by factors such as the dosage, size, morphology, and surface functional groups of nanomaterials. There is huge potential and a broad prospect for the application of nanomaterials in regulating the IMB for achieving an optimal therapeutic effect for antibiotics, oral vaccines, drug carriers, and so on.

Orally administered nano-polystyrene caused vitellogenin alteration and oxidative stress in the red swamp crayfish (Procambarus clarkii)

Nanoplastics (≤100 nm) represent the smallest fraction of plastic litter and may result in the aquatic environment as degradation products of larger plastic material. To date, few studies focused on the interactions of micro- and nanoplastics with freshwater Decapoda. The red swamp crayfish (Procambarus clarkii, Girard, 1852) is an invasive species able to tolerate highly perturbed environments. As a benthic opportunistic feeder, this species may be susceptible to plastic ingestion. In this study, adult P. clarkii, at intermolt stage, were exposed to 100 μg of 100 nm carboxylated polystyrene nanoparticles (PS NPs) through diet in a 72 h acute toxicity test. An integrated approach was conceived to assess the biological effects of PS NPs, by analyzing both transcriptomic and physiological responses. Total hemocyte counts, basal and total phenoloxidase activities, glycemia and total protein concentration were investigated in crayfish hemolymph at 0 h, 24 h, 48 h and 72 h from PS NPs administration to evaluate general stress response over time. Differentially expressed genes (DEGs) in the hemocytes and hepatopancreas were analyzed to ascertain the response of crayfish to PS NP challenge after 72 h. At a physiological level, crayfish were able to compensate for the induced stress, not exceeding generic stress thresholds. The RNA-Sequencing analysis revealed the altered expression of few genes involved in immune response, oxidative stress, gene transcription and translation, protein degradation, lipid metabolism, oxygen demand, and reproduction after PS NPs exposure. This study suggests that a low concentration of PS NPs may induce mild stress in crayfish, and sheds light on molecular pathways possibly involved in nanoplastic toxicity.

Antibacterial effects of extracted corn zein with garlic extract-based nanoemulsion on the shelf life of Vannamei prawn (Litopenaeus vannamei) at refrigerated temperature

BACKGROUND

Litopenaeus vannamei is one of the most perishable foods due to microorganism growth. Using essential oil-based nanoemulsion as a biodegradable and edible coating can enhance the shelf life of shrimp at refrigerated temperature through retarding microbial growth compared to synthetic coatings.

METHODS

Zein was extracted from 50 g dry milled corn with ethanol. Garlic essential oil was prepared by mixing with Tween 80. Nanoemulsion was prepared in an ultrasonic bath. DLS analysis, turbidity, and stability of nanoemulsions were performed. Radical scavenging activity, and total phenol content were done for evaluation of garlic essential oil and nanoemulsion. A 10% zein solution was prepared using ethanol 95% and glycerol plasticizer (2.5%). In the end, various microbial analysis, peroxide value, the thiobarbituric acid reactive substance (TBARS) value, the total volatile basic nitrogen (TVB-N) values, and sensory evaluations of different shrimp samples were determined.

RESULTS

Corn zein along with garlic-based nanoemulsion, had a great impact on the TVB-N, TBARS, and peroxide value (which indicated that z+24% garlic nanoemulsion group was the lowest among other groups on days 3, 7, and 14 (p < 0.05) as well as microbial properties (garlic EO nanoemulsion had significantly better antibacterial effectiveness compared to other groups (p < 0.05)), and sensory evaluation (the z+24% garlic nanoemulsion sample received a significantly higher score than other groups (p < 0.05)) of Litopenaeus vannamei.

CONCLUSIONS

Corn zein nanoemulsion functioned as an antioxidant and antimicrobial agent, increasing the shelf life of Litopenaeus vannamei at refrigerated temperature.

PRACTICAL APPLICATION

Emerging nanotechnology-based approaches with no side-effects on immune system of consumers plays a vital role in bioactive packaging, and on reduction of food spoilage or food poisoning in the transportation, exporting, and distribution stages of food products, especially marine-based products with cold chain transportation. Additionally, it can reduce aquaculture and environmental risks due to the usage of chemical agents used in packaging. Our results showed that administration of a corn zein with nanoemulsion of garlic extract can prolong shelf life of Litopenaeus vannamei. The paper should be of interest to readers such as food microbiologists, aquaculture scientists, fisheries scientists, marine biologists, biomaterial scientists, food packaging industrialists, medical microbiologists, public health managers, and health system managers.

Dietary polystyrene nanoplastics exposure alters liver lipid metabolism and muscle nutritional quality in carnivorous marine fish large yellow croaker (Larimichthys crocea)

Nanoplastics (NPs) cause various adverse effects on marine fish. However, effects of dietary NPs exposure on liver lipid metabolism and muscle nutritional quality of carnivorous marine fish are not fully understood. In this study, a 21-day feeding test was conducted to simulate the food chain transfer of polystyrene nanoplastics (PS NPs) and then evaluate effects of different dietary PS NPs levels on the survival, growth performance, liver lipid metabolism, and muscle nutritional quality of large yellow croaker Larimichthys crocea. Results indicated that the survival and growth of large yellow croaker decreased with the increase of PS NPs levels. Moreover, PS NPs induced excessive liver lipid accumulation by down-regulating the expression of lipolysis-related genes and inhibiting the AMPK-PPARα signaling pathway. In vitro, PS NPs could be accumulated in hepatocytes, reduce cell viability, and disrupt lipid metabolism of hepatocytes. Also, we found for the first time that PS NPs altered fatty acid composition and texture of fish muscle by enhancing oxidative stress and disrupting lipid metabolism. Overall, this study indicated that PS NPs induced liver lipid deposition by inhibiting lipolysis, and demonstrated that PS NPs altered the nutritional quality of fish, which might cause potential health effects for human consumers.

Effects of Ocean Acidification and Microplastics on Microflora Community Composition in the Digestive Tract of the Thick Shell Mussel Mytilus coruscus Through 16S RNA Gene Sequencing

Ocean acidification and microplastic pollution is a global environmental threat, this research evaluated the effects of ocean acidification and microplastics on mussel digestive tract microbial community. The 16S rRNA gene was sequenced to characterize the flora. Species diversity in the samples was assessed by clustering valid tags on 97% similarity. Bacteroidetes, Firmicutes and Proteobacteria were the three most abundant genera in the four groups, with Bacteroidetes showing the highest diversity. However, no differences in flora structure were evident under various treatments. Phylogenetic relationship analysis revealed Bacteroidetes and Firmicutes had the highest OTU diversity. The weighted UniFrac distance, principal coordinate analysis (PCoA), unweighted pair group method with arithmetic mean (UPGMA) cluster tree and analysis of molecular variance (AMOVA) evaluation results for all samples also showed that changes in pH and microplastics concentration did not significantly affect the microbial community structure in the mussel digestive tract. The results presented the no significant effects of ocean acidification and microplastics intake on mussel intestinal diversity.

Microplastic: A potential threat to human and animal health by interfering with the intestinal barrier function and changing the intestinal microenvironment

Plastics are widely used in many fields due to their stable physical and chemical properties, and their global production and usage increase significantly every year, which leads to the accumulation of microplastics in the entire ecosystem. Numerous studies have shown that microplastics (MPs) have harmful effects on living organisms. This review aims to provide a comprehensive conclusion of the current knowledge of the impacts of MPs on the stability of the gut microenvironment, especially on the gut barrier. Studies showed that exposure to MPs could cause oxidative damage and inflammation in the gut, as well as the destruction of the gut epithelium, reduction of the mucus layer, microbial disorders, and immune cell toxicity. Although there are few reports directly related to humans, we hoped that this review could bring together more and more evidence that exposure to MPs results in disturbances of the intestinal microenvironment. Therefore, it is necessary to investigate their threats to human health further.

Influence of the co-exposure of microplastics and tetrabromobisphenol A on human gut: Simulation in vitro with human cell Caco-2 and gut microbiota

Microplastics (MPs) pollution becomes an emergent threat to the ecosystem, and its joint effect with organic contaminants will cause more severe consequences. Recently, MPs has been observed in human feces, suggesting that we are exposed to an uncertain danger. In this study, the joint effect of polyethylene microplastics particles (PEMPs) and Tetrabromobisphenol A (TBBPA) on human gut was explored through the simulation experiment in vitro with human cell Caco-2 and gut microbiota. The toxicity of TBBPA and PEMPs on Caco-2 human cells was considered by physiological and biochemical indexes such as cell proliferation, cell cycle, reactive oxygen species, lactate dehydrogenase release, and mitochondrial membrane potential. Besides, microbial community diversity, community structure, and function changes of gut microbiota were investigated using Illumina 16S rRNA gene MiSeq sequencing to reveal the influence of TBBPA and PEMPs on human gut microbiota. The results indicated that both PEMPs and TBBPA would deteriorate the status of Caco-2 cells, and TBBPA played a major role in it; meanwhile, PEMPs affected Caco-2 cells at high concentrations. Particularly, TBBPA and PEMPs exhibited a joint effect on Caco-2 cells to a certain degree. TBBPA selectivity inhibited the growth of gram-positive bacteria such as Enterococcus and Lactobacillus, contributing to the thriving of gram-negative bacteria such as Escherichia and Bacteroides. The existence of PEMPs would enhance the proportion of Clostridium, Bacteroides, and Escherichia. Community composition changed dramatically with the interference of PEMPs and TBBPA; this was undesirable to the healthy homeostasis of the human gut. PICRUSt analysis determined both PEMPs and TBBPA interfered with the metabolism pathways of gut microbiota. Hence, the threat of MPs and TBBPA to humans should arouse vigilance.

Comparative evaluation of high-density polyethylene and polystyrene microplastics pollutants: Uptake, elimination and effects in mussel

The high-density polyethylene (HDPE) and the polystyrene (PS), which are typical microplastic contaminants, are frequently detected in the environment and have potential hazard to environmental health. In this study, the accumulation, elimination, tissue distribution and potential effects of the HDPE and the PS in the mussels (Mytilus galloprovincialis) were evaluated. The HDPE and the PS were found in various tissues (digestive gland > gill > gonad ≈ muscle) with no difference in distribution patterns. The accumulation of the HDPE and the PS rapidly increased in the first 48 h exposure, and the accumulation of HDPE was higher than that of PS. After 144 h of elimination, most of the HDPE and the PS were cleared by mussels. In addition, the activities of superoxide dismutase (SOD), catalase (CAT) and the content of oxidized glutathione considerably increased, indicating that the HDPE and the PS induced oxidative stress and prevented oxidative damage in elimination. The metabolomic analysis suggested that exposure to HDPE and PS induced alterations in the metabolic profiles of mussel. Differential metabolites were involved in energy metabolism, lipid metabolism, tricarboxylic acid cycle and neurotoxic response., and Meanwhile, the PS had a lower effect on mussel metabolism during elimination, but the effect of HDPE was increased. Overall, this study elucidated that the HDPE and the PS caused adverse effects on the mussels and provided insights toward understanding the hazard of different microplastics on aquatic organisms.

Toxic effects of cadmium and lead exposure on intestinal histology, oxidative stress response, and microbial community of Pacific white shrimp Litopenaeus vannamei

Cadmium (Cd) and lead (Pb) are two hazardous pollutants that threaten shrimp farming. The intestine is an important organ for digestion and immunity. We separately exposed Pacific white shrimp Litopenaeus vannamei to 500 μg/L Cd or 500 μg/L Pb seawater for 7 days, and 45 shrimp from each group were used to evaluate the changes of intestinal histopathological, oxidative stress, and microbiota composition. After Cd and Pb exposure, shrimp intestine appeared significant mucosal damage and oxidative stress, and the microbiota variation were induced. Specifically, the abundance of the phyla Bacteroidetes and Actinobacteria were induced, that of Proteobacteria and Firmicutes were deduced. The abundances of putative beneficial bacteria (Lactobacillus, Weissella, Demequina, Formosa and Ruegeria) and potentially pathogenic bacteria (Vibrio and Photobacterium) were fluctuated. Furthermore, the nutrient metabolic function of intestinal microbes was significantly altered. We concluded that Cd and Pb exposure had negative effects on the intestinal health of shrimp.

Effects of Microplastics, Polystyrene, and Polyethylene on Antioxidants, Metabolic Enzymes, HSP-70, and Myostatin Expressions in the Giant River Prawn Macrobrachium rosenbergii: Impact on Survival and Growth

This study was conducted to understand the biological effects of microplastics (MPs), polystyrene microspheres (PSM), and polyethylene microparticles (PEM) in the juveniles of the giant river prawn, Macrobrachium rosenbergii. The PSM (0.5-1.0 µm) and PEM (30.0-150.0 µm) were separately incorporated into the artificial diets with concentrations of 1, 5, and 10 mg per 100 g. The prawns were fed with these diets for a period of 60 days. Compared with control, the following dose-dependent changes have been recorded in PSM and PEM incorporated feeds fed prawns: declines in the survival rate, length and weight gains; increase in activities of antioxidant enzymes, such as superoxide dismutase, catalase, glutathione s-transferase, and glutathione peroxidase (GPx); elevated concentrations of reduced glutathione (GSH) and malondialdehyde; decreased activities of metabolic enzymes, such as glutamic oxaloacetic transaminase and glutamic pyruvic transaminase; higher total RNA in hepatopancreas (HP) of PSM fed prawns compared with that of PEM; higher total RNA in muscle (MU) of PEM-fed prawns compared with that of PSM; prominent cDNA bands in 150 bp regions; up-regulated heat shock protein (HSP70) gene in HP; down-regulation of HSP70 gene in MU of PSM-fed prawns only; down-regulated myostatin (MSTN) gene. These results suggest that these MPs have affected the survival and growth, activated the antioxidant defense, inhibit the metabolic enzymes, positively regulated the HSP70 gene, and negatively regulated the MSTN gene in M. rosenbergii. Therefore, exposures to PSM and PEM caused biological effects in this species of prawn.