Microplastics and their interactions with microbiota

GIS-based integration of marine data for assessment and management of a highly anthropized coastal area

Monitoring coastal marine environments by evaluating and comparing their chemical, physical, biological, and anthropogenic components is essential for ecological assessment and socio-economic development. In this study, we conducted an integrated multivariate analysis to assess the descriptors of the Marine Strategy Framework Directive at a regional scale in the Tyrrhenian Sea (Italy), with a specific focus on the densely populated coastal zone of the Campania region. Physical, chemical, and biological data were collected and analyzed in 22 sampling sites during three oceanographic surveys in the Gulf of Gaeta (GoG), Naples (GoN), and Salerno (GoS) in autumn 2020. Our results indicated that these three gulfs were distinct overall, with GoN being more divergent and heterogeneous than GoG and GoS. The marine area studied in the GoN had more favorable hydrographic and trophic conditions and food web characteristics, except for the mesozooplankton biomass, and was closer to socio-economic factors compared to the GoS and GoG. Our analysis helped us find the key ecological features that define different sub-regions and connect them to social and economic factors, including human activities. We highlighted the relevance of primary and secondary variables in terms of the comprehensive ecological assessment of a marine area and its impact on specific socio-economic activities. These findings support the need to describe and integrate multiple descriptors at the spatial scale.

A co-conserved gene pair supports Caulobacter iron homeostasis during chelation stress

Synthetic metal chelators are widely used in industrial, clinical, and agricultural settings, leading to their accumulation in the environment. We measured the growth of Caulobacter crescentus, a soil and aquatic bacterium, in the presence of the ubiquitous chelator ethylenediaminetetraacetic acid (EDTA) and found that it restricts growth by lowering intracellular iron levels. Using barcoded transposon sequencing, we identified an operonic gene pair, cciT-cciO, that is required to maintain iron homeostasis in laboratory media during EDTA challenge. cciT encodes one of four TonB-dependent transporters that are regulated by the ferric uptake repressor (Fur) and stands out among this group of genes in its ability to support Caulobacter growth across diverse media conditions. The function of CciT strictly requires cciO, which encodes a cytoplasmic FeII dioxygenase-family protein. Our results thus define a functional partnership between an outer membrane iron receptor and a cytoplasmic dioxygenase that are broadly co-conserved in Proteobacteria. We expanded our analysis to natural environments by examining the growth of mutant strains in freshwater from two lakes, each with biochemical and geochemical profiles that differ markedly from standard laboratory media. In lake water, Caulobacter growth did not require cciT or cciO and was less affected by EDTA treatment. This result aligns with our observation that EDTA toxicity is influenced by common forms of biologically chelated iron and the spectrum of free cations present in the medium. Our study defines a conserved iron acquisition system in Proteobacteria and bridges laboratory-based physiology studies with real-world conditions.IMPORTANCEMetal-chelating chemicals are widely used across industries, including as preservatives in the food sector, but their full impact on microbial physiology is not well understood. We identified two genes, cciT and cciO, that function together to support Caulobacter crescentus iron balance when cells are exposed to the common synthetic chelator, EDTA. CciT is an outer membrane transporter and CciO is a dioxygenase-family protein that are mutually conserved in many bacteria, including human pathogens where mutations in cciT homologs are linked to clinical resistance to the siderophore antibiotic cefiderocol. This study identifies a conserved genetic system that supports iron homeostasis during chelation stress and illuminates the iron acquisition versatility and stress resilience of Caulobacter in freshwater environments.

A co-conserved gene pair supports Caulobacter iron homeostasis during chelation stress

Synthetic metal chelators are widely used in industrial, clinical, and agricultural settings, leading to their accumulation in the environment. We measured the growth of Caulobacter crescentus, a soil and aquatic bacterium, in the presence of the ubiquitous chelator ethylenediaminetetraacetic acid (EDTA) and found that it restricts growth by lowering intracellular iron levels. Using barcoded transposon sequencing, we identified an operonic gene pair, cciT-cciO, that is required to maintain iron homeostasis in laboratory media during EDTA challenge. cciT encodes one of four TonB-dependent transporters that are regulated by the ferric uptake repressor (Fur) and stands out among this group of genes in its ability to support Caulobacter growth across diverse media conditions. The function of CciT strictly requires cciO, which encodes a cytoplasmic FeII dioxygenase-family protein. Our results thus define a functional partnership between an outer membrane iron receptor and a cytoplasmic dioxygenase that are broadly co-conserved in Proteobacteria. We expanded our analysis to natural environments by examining the growth of mutant strains in freshwater from two lakes, each with biochemical and geochemical profiles that differ markedly from standard laboratory media. In lake water, Caulobacter growth did not require cciT or cciO and was less affected by EDTA treatment. This result aligns with our observation that EDTA toxicity is influenced by common forms of biologically chelated iron and the spectrum of free cations present in the medium. Our study defines a conserved iron acquisition system in Proteobacteria and bridges laboratory-based physiology studies with real-world conditions.

IMPORTANCE

Metal-chelating chemicals are widely used across industries, including as preservatives in the food sector, but their full impact on microbial physiology is not well understood. We identified two genes, cciT and cciO, that function together to support Caulobacter crescentus iron balance when cells are exposed to the common synthetic chelator, EDTA. CciT is an outer membrane transporter and CciO is a dioxygenase-family protein that are mutually conserved in many bacteria, including several human pathogens, where mutations in cciT homologs are linked to clinical resistance to the siderophore antibiotic, cefiderocol. This study identifies a conserved genetic system that supports iron homeostasis during chelation stress and illuminates the iron acquisition versatility and stress resilience of Caulobacter in freshwater environments.

Toxicological complexity of microplastics in terrestrial ecosystems

Microplastics (MPs), defined as plastic debris, smaller than <5 mm, are viewed as persistent contaminants that significantly modify terrestrial ecosystems and biodiversity by altering soil microbiota, structure, and functions. This paper summarizes MPs' interactions with various pollutants, including heavy metals and pesticides, also addressing socio-economic impacts, such as reduced agricultural yields and threats to regional fisheries. The study emphasizes the need for an on the basis of waste management model to mitigate these effects, advocating for collaborative efforts among stakeholders. Also, interdisciplinary studies incorporating material sciences, ecology, and environmental policy are essential to confront the challenges of MPs to ecological services. Additionally, the review highlights how MPs can serve as vectors for toxins to damage soil health and species survival. The overview underscores a complex interplay between environmental and socio-economic systems, addressing the urgency of harnessing MPs pollution and protecting ecosystem integrity and sustainability.

Influence of selected dosages of plastic microparticles on the porcine fecal microbiome

Studies conducted so far have shown that nano- and microplastic may disturb the intestinal microenvironment by interacting with the intestinal epithelium and the gut microbiota. Depending on the research model used, the effect on the microbiome is different-an increase or decrease in selected taxa resulting in the development of dysbiosis. Dysbiosis may be associated with intestinal inflammation, development of mental disorders or diabetes. The aim of the study was to analyze the intestinal microbiome in 15 gilts divided into 3 research groups (n = 5; control group, receiving micropartices at a dose 0.1 g/day (LD) and 1 g/day (HD)). Feaces were collected before and after 28 days of exposure to PET microplastics. The analysis of the intestinal microbiome was performed using next-generation sequencing. Alpha and beta diversity indices were compared, showing, that repetition affected only the abundance indices in the control and LD groups, but not in the HD group. The relationships between the number of reads at the phylum, genus and species level and the microplastic dose were calculated using statistical methods (r-Pearson correlation, generalized regression model, analysis of variance). The statistical analysis revealed, that populations of Family XIII AD3011 group, Coprococcus, V9D2013 group, UCG-010 and Sphaerochaeta increased with increasing MP-PET dose. The above-mentioned taxa are mainly responsible for the production of short-chain fatty acids (SCFA). It may be assumed, that SCFA are one of the mechanisms involved in the response to oral exposure to MP-PET.

Methane oxidation coupling with heavy metal and microplastic transformations for biochar-mediated landfill cover soil

The impact of co-occurring heavy metal (HM) and microplastic (MP) pollution on methane (CH4) oxidation by methanotrophs (MOB) in landfill cover soil (LCS) and the role of biochar in mediating these collaborative transformations remains unclear. This study conducted batch-scale experiments using LCS treated with individual or combined HMs and MPs, with or without biochar amendment. Differentiation in methanotrophic activities, HM transformations, MP aging, soil properties, microbial communities, and functional genes across the groups were analyzed. Biochar proved essential in sustaining efficient CH4 oxidation under HM and MP stress, mainly by diversifying MOB, and enhancing polysaccharide secretion to mitigate environmental stress. While low levels of HMs slightly inhibited CH4 oxidation, high HM concentration enhanced methanotrophic activities by promoting electron transfer process. MPs consistently stimulated CH4 oxidation, exerting a stronger influence than HMs. Notably, the simultaneous presence of low levels of HMs and MPs synergistically boosted CH4 oxidation, linked to distinct microbial evolution and adaptation. Methanotrophic activities were demonstrated to affect the fate of HMs and MPs. Complete passivation of Cu was readily achieved, whereas Zn stabilization was negatively influenced by biochar and MPs. The aging of MPs was also partially suppressed by biochar and HM adsorption.

Links between fecal microplastics and parameters related to metabolic dysfunction-associated steatotic liver disease (MASLD) in humans: An exploratory study

Microplastics (MPs) can persist in the environment and human body. Murine studies showed that exposure to MPs could cause metabolic dysregulation, contributing metabolic dysfunction-associated steatotic liver disease (MASLD) or steatohepatitis (MASH). However, research on the role of MPs in humans is limited. Thus, we aimed to assess links between human fecal MPs and liver histology, gene expression, immune cells and intestinal microbiota (IM). We included 6 lean healthy liver donors and 6 normal liver (obese) and 11 MASH patients. Overall, pre-BSx, we observed no significant differences in fecal MPs between groups. However, fecal MP fibers and total MPs positively correlated with portal and total macrophages and total killer T cells while total fecal MPs were positively correlated with natural killer cells. Additionally, 19 genes related to immune system and apoptosis correlated with fecal MPs at baseline. Fecal MP fibers correlated positively with fecal Bifidobacterium and negatively with Lachnospiraceae. Patients with MASH (n = 11) were re-assessed 12-months post-bariatric surgery (BSx) and we found that those with persistent disease (n = 4) had higher fecal MP fragments than those with normalized liver histology (n = 7). At 12-month post-BSx, MP fragments positively correlated with helper T cells and total MPs positively correlated with natural killer T cells and B cells. Our study is the first to look at 1) the role of MPs in MASH and its association with IM, immune cells and hepatic gene expression and 2) look at the role of MPs longitudinally in MASH persistence following BSx. Future research should further explore this relationship.

Local and systemic effects of microplastic particles through cell damage, release of chemicals and drugs, dysbiosis, and interference with the absorption of nutrients

Microplastic particles (MPs) have been detected in a variety of environmental samples, including soil, water, food, and air. Cellular studies and animal exposures reported that exposure to MPs composed of different polymers might result in adverse effects at the portal of entry (local) or throughout the body (systemic). The most relevant routes of particle uptake into the body are oral and respiratory exposure. This review describes the various processes that may contribute to the adverse effects of MPs. Only MPs up to 5 µm were found to cross epithelial barriers to a significant extent. However, MPs may also exert a detrimental impact on human health by acting at the epithelial barrier and within the lumen of the orogastrointestinal and respiratory tract. The potential for adverse effects on human health resulting from the leaching, sorption, and desorption of chemicals, as well as the impact of MPs on nutritional status and dysbiosis, are reviewed. In vitro models are suggested as a means of (1) assessing permeation, (2) determining adverse effects on cells of the epithelial barrier, (3) examining influence of digestive fluids on leaching, desorption, and particle properties, and (4) role of microbiota-epithelial cell interactions. The contribution of these mechanisms to human health depends upon exposure levels, which unfortunately have been estimated very differently.

The role of algae in regulating the fate of microplastics: A review for processes, mechanisms, and influencing factors

As an important emerging pollutant, the fate of microplastics (MPs) in ecosystems is of growing global concern. In addition to hydrodynamics and animals, algae can also affect the transport of MPs in aquatic environments, which could potentially remove MPs from the water column. Although researchers have conducted many studies on the sink of MPs regulated by algae in both marine and freshwater environments, there is still a lack of comprehensive understanding coupled with the increasingly scattered study contents and findings. This review aims to provide a systematic discussion of the processes, mechanisms, and influencing factors, which are coupled with the sink of MPs changes by algae. The main processes identified include retention, flocculation, deposition, and degradation. The retention of MPs is achieved by adhesion of MPs to algae or embedment/encrustation of MPs within the epibiont matrix of algae, thereby preventing MPs from migrating with water currents. The extracellular polymeric substances (EPS) and enzymes produced by algal metabolic activities can lead not only to the formation of aggregates containing MPs but also to the biodegradation of MPs. The processes that algae alter the fate of MPs in aquatic environments are very complex and can be influenced by various factors such as algal attributes, microplastic characteristics and environmental conditions. This review provides insights into recent advances in the fate of aquatic MPs and highlights the need for further research on MPs-algae interactions, potentially shortening the knowledge gap in the sink of MPs in aquatic ecosystems.

The role of gut microbiota in MP/NP-induced toxicity

Microplastics (MPs) and nanoplastics (NPs) are globally recognized as emerging environmental pollutants in various environmental media, posing potential threats to ecosystems and human health. MPs/NPs are unavoidably ingested by humans, mainly through contaminated food and drinks, impairing the gastrointestinal ecology and seriously impacting the human body. The specific role of gut microbiota in the gastrointestinal tract upon MP/NP exposure remains unknown. Given the importance of gut microbiota in metabolism, immunity, and homeostasis, this review aims to enhance our current understanding of the role of gut microbiota in MP/NP-induced toxicity. First, it discusses human exposure to MPs/NPs through the diet and MP/NP-induced adverse effects on the respiratory, digestive, neural, urinary, reproductive, and immune systems. Second, it elucidates the complex interactions between the gut microbiota and MPs/NPs. MPs/NPs can disrupt gut microbiota homeostasis, while the gut microbiota can degrade MPs/NPs. Third, it reveals the role of the gut microbiota in MP/NP-mediated systematic toxicity. MPs/NPs cause direct intestinal toxicity and indirect toxicity in other organs via regulating the gut-brain, gut-liver, and gut-lung axes. Finally, novel approaches such as dietary interventions, prebiotics, probiotics, polyphenols, engineered bacteria, microalgae, and micro/nanorobots are recommended to reduce MP/NP toxicity in humans. Overall, this review provides a theoretical basis for targeting the gut microbiota to study MP/NP toxicity and develop novel strategies for its mitigation.

The comparative toxicity of biobased, modified biobased, biodegradable, and petrochemical-based microplastics on the brackish water flea Diaphanosoma celebensis

The escalating production and improper disposal of petrochemical-based plastics have led to a global pollution issue with microplastics (MPs), which pose a significant ecological threat. Biobased and biodegradable plastics are believed to mitigate plastic pollution. However, their environmental fate and toxicity remain poorly understood. This study compares the in vivo effects of different types of MPs, poly(butylene adipate-co-terephthalate) as a biodegradable plastic, polylactic acid (PLA) as a biobased plastic, β-cyclodextrin-grafted PLA as a modified biobased plastic, and low density polyethylene as the reference petrochemical-based plastic, on the key aquatic primary consumer Diaphanosoma celebensis. Exposure to MPs resulted in significant reproductive decline, with comparable effects observed irrespective of MP type or concentration. Exposure to MPs induced distinct responses in redox stress, with transcriptional profiling revealing differential gene expression patterns that indicate varied cellular responses to different types of MPs. ATP-binding cassette transporter activity assays demonstrated altered efflux activity, mainly in response to modified biobased and biodegradable MPs. Overall, this study highlights the comparable in vivo and in vitro effects of biobased, biodegradable, and petrochemical-based MPs on aquatic primary consumers, highlighting their potential ecological implications.

Microbial Allies in Plastic Degradation: Specific bacterial genera as universal plastic-degraders in various environments

Microbiological degradation of polymers offers a promising approach for mitigating environmental plastic pollution. This study (i) elucidated the diversity and structure of bacterial microbiomes from distinct environments (landfill soil, sewage sludge, and river water) characterized by specific physicochemical parameters, and (ii) utilized environment-derived microbial cultures enriched with microplastics (MPs) to investigate the degradation of polymers and identify culturable bacterial strains contributing to the plastisphere. We found that alpha diversity was notably higher in river water (∼20%) compared to landfill soil and sewage sludge. Dominant phyla included Pseudomonadota in sewage sludge (39.1%) and water (23.7%), while Actinomycetota prevailed in soil (38.5%). A multistage experiment, involving successive subcultures of environmental microbiomes exposed to polypropylene (PP), polyvinyl chloride (PVC), polycarbonate (PC), and polylactic acid (PLA), facilitated the assessment of MPs degradation processes. Analysis of carbonyl indices CIs and FTIR spectra revealed substantial structural changes in the treatment PVC-landfill soil, as well as in PLA- and PC-sludge enriched cultures. Further, using enriched cultures as a source of microorganisms, the study obtained 17 strains of plastic degraders from landfill soil, 14 from sewage sludge, and 6 from river water. Remarkably, similar bacterial genera were isolated across environmental microbiomes regardless of the MPs substrate used in enriched cultures. Among the 37 identified strains, Pseudomonadota predominated (64.86%) and were accompanied by Bacteroidota (16.22%), Actinomycetota (13.51%), and Bacillota (5.41%). This study highlights the complex relationship between microbiome diversity and the biodegradation efficiency of plastics, showing the potential for using microbial communities in the plastic pollution management.

Hybrid mechanism of microplastics degradation via biological and chemical process during composting

Little is known about the synergistic effects of abiotic aging and biodegradation on microplastics (MPs) transformation in the environment. Herein, a hybrid process of MPs degradation was proposed by analyzing the effect of microorganisms and abiotic aging on aging MPs and non-aging MPs degradation during composting. The results showed that composting facilitated the oxidation and depolymerization of aging MPs, and its degradation efficiency was about three times that of non-aging MPs. Further investigation revealed that aging MPs contained higher abundance of plastic-degrading bacteria and enzyme activity than non-aging MPs. In addition, free radicals also influenced the degradation of MPs. However, path model and shielding experiments confirmed that free radicals mainly facilitated the non-aging MPs degradation (contribution was 68.8 %), while aging MPs was easily degraded by microorganisms (contribution was 72.6 %). This study provides promising strategies for scaling up plastic treatment in bioreactors through a hybrid collaboration of biological and abiotic processes.

Natural and simulated weathering of polystyrene: A molecular view of the polymeric interface

This work presents the changing abundance of surface functional groups (SFGs) on polystyrene (PS) upon weathering within one or a few molecular monolayers from a molecular point of view. PS particles were aged by exposing it to a gas flow of typically (5 %) O3 in O2 (PSO3), UV radiation using a solar simulator under controlled conditions in the laboratory (PSSS) and to the water/air interface immerged in a freshwater lake for 2 months (PSL). The chemical composition of the interface of weathered, compared to pristine (virgin or PSV) material was established using a titration technique that probed the chemical composition of the molecular interface of the polymer. The main conclusions of this exploratory study are: (a) The interface of PS changes significantly compared to ATR-FTIR spectra that do not show additional absorptions in the mid-IR spectrum over a penetration depth of more than hundred monolayers at 10 μm; (b) The average surface functionalization of the gas-solid interface, corresponding to the sum of all examined types of SFG, increases from 20 % of a monolayer for PSV to 40, 50 and 84 % for PSL, PSO3 and PSSS, respectively; (c) in all cases the most important SFG was surface -OH ranging from 11.2 to 64 % for PSV and PSSS, respectively; (d) each PS sample shows a characteristic SFG pattern or fingerprint using several probe gases; (e) O3 interaction led to interface acidification; (f) UV treatment leads to the highest degree of surface -OH functionalization compared to PSO3 and PSL. The accumulation of SFG's renders the interface more reactive towards adsorption of probe gases.

Identification and morphological characterization of different types of plastic microparticles

The knowledge of the polymeric composition of microplastics (MPs) is interesting because offers useful information on the resistance, durability, and degradability of these materials, also allowing progress in the control of this contamination. However, there is currently a lack of reliable standardized methods for the identification, and characterization of the plastic microparticles. This work uses different techniques in a complementary manner for the identification, and characterization of MPs that more frequently are found in the environment. A total of 10 types of plastics were collected (polystyrene (PS), polyethylene terephthalate (PETE), polyethylene (PE), high- and low-density polyethylene (HDPE and LDPE, respectively), polyvinyl chloride (PVC), polypropylene (PP), polytetrafluoroethylene (PTFE), Polyamide (PA, Nylon 6,6) and poly-carbonate (PC)) and their chemical identification were analyzed by reflectance-attenuated infrared (FTIR-ATR). Furthermore, the samples were observed using light microscopy, and scan-ning electron microscopy (SEM). Also, staining with 12 different dyes was performed to improve the identification of microplastics. The results of this study revealed that PETE, PE, HDPE and LDPE, whose SEM images exhibited smoothness and flat uniformity of their surface, were not (or less) susceptible to adsorb staining solutions while PP, PA, PVC, and PTFE, were capable of adsorbing the dye solutions.

Microplastics and environmental effects: investigating the effects of microplastics on aquatic habitats and their impact on human health

Microplastics (MPs) are particles with a diameter of <5 mm. The disposal of plastic waste into the environment poses a significant and pressing issue concern globally. Growing worry has been expressed in recent years over the impact of MPs on both human health and the entire natural ecosystem. MPs impact the feeding and digestive capabilities of marine organisms, as well as hinder the development of plant roots and leaves. Numerous studies have shown that the majority of individuals consume substantial quantities of MPs either through their dietary intake or by inhaling them. MPs have been identified in various human biological samples, such as lungs, stool, placenta, sputum, breast milk, liver, and blood. MPs can cause various illnesses in humans, depending on how they enter the body. Healthy and sustainable ecosystems depend on the proper functioning of microbiota, however, MPs disrupt the balance of microbiota. Also, due to their high surface area compared to their volume and chemical characteristics, MPs act as pollutant absorbers in different environments. Multiple policies and initiatives exist at both the domestic and global levels to mitigate pollution caused by MPs. Various techniques are currently employed to remove MPs, such as biodegradation, filtration systems, incineration, landfill disposal, and recycling, among others. In this review, we will discuss the sources and types of MPs, the presence of MPs in different environments and food, the impact of MPs on human health and microbiota, mechanisms of pollutant adsorption on MPs, and the methods of removing MPs with algae and microbes.

Pollutants, microbiota and immune system: frenemies within the gut

Pollution is a critical concern of modern society for its heterogeneous effects on human health, despite a widespread lack of awareness. Environmental pollutants promote several pathologies through different molecular mechanisms. Pollutants can affect the immune system and related pathways, perturbing its regulation and triggering pro-inflammatory responses. The exposure to several pollutants also leads to alterations in gut microbiota with a decreasing abundance of beneficial microbes, such as short-chain fatty acid-producing bacteria, and an overgrowth of pro-inflammatory species. The subsequent intestinal barrier dysfunction, together with oxidative stress and increased inflammatory responses, plays a role in the pathogenesis of gastrointestinal inflammatory diseases. Moreover, pollutants encourage the inflammation-dysplasia-carcinoma sequence through various mechanisms, such as oxidative stress, dysregulation of cellular signalling pathways, cell cycle impairment and genomic instability. In this narrative review, we will describe the interplay between pollutants, gut microbiota, and the immune system, focusing on their relationship with inflammatory bowel diseases and colorectal cancer. Understanding the biological mechanisms underlying the health-to-disease transition may allow the design of public health policies aimed at reducing the burden of disease related to pollutants.

Combined effects of norfloxacin and polystyrene nanoparticles on the oxidative stress and gut health of the juvenile horseshoe crab Tachypleus tridentatus

Pollution with anthropogenic contaminants including antibiotics and nanoplastics leads to gradual deterioration of the marine environment, which threatens endangered species such as the horseshoe crab Tachypleus tridentatus. We assessed the potential toxic mechanisms of an antibiotic (norfloxacin, 0, 0.5, 5 μg/L) and polystyrene nanoparticles (104 particles/L) in T. tridentatus using biomarkers of tissue redox status, molting, and gut microbiota. Exposure to single and combined pollutants led to disturbance of redox balance during short-term (7 days) exposure indicated by elevated level of a lipid peroxidation product, malondialdehyde (MDA). After prolonged (14-21 days) exposure, compensatory upregulation of antioxidants (catalase and glutathione but not superoxide dismutase) was observed, and MDA levels returned to the baseline in most experimental exposures. Transcript levels of molting-related genes (ecdysone receptor, retinoic acid X alpha receptor and calmodulin A) and a molecular chaperone (cognate heat shock protein 70) showed weak evidence of response to polystyrene nanoparticles and norfloxacin. The gut microbiota T. tridentatus was altered by exposures to norfloxacin and polystyrene nanoparticles shown by elevated relative abundance of Bacteroidetes. At the functional level, evidence of suppression by norfloxacin and polystyrene nanoparticles was found in multiple intestinal microbiome pathways related to the genetic information processing, metabolism, organismal systems, and environmental information processing. Future studies are needed to assess the physiological and health consequences of microbiome dysbiosis caused by norfloxacin and polystyrene nanoparticles and assist the environmental risk assessment of these pollutants in the wild populations of the horseshoe crabs.

Polyethylene terephthalate waste derived nanomaterials (WDNMs) and its utilization in electrochemical devices

Plastics are a vital component of our daily lives in the contemporary globalization period; they are present in all facets of modern life. Because the bulk of synthetic plastics utilized in the market are non-biodegradable by nature, the issues associated with their contamination are unavoidable in an era dominated by polymers. Polyethylene terephthalate (PET), which is extensively used in industries such as automotive, packaging, textile, food, and beverages production represents a major share of these non-biodegradable polymer productions. Given its extensive application across various sectors, PET usage results in a considerable amount of post-consumer waste, majority of which require disposal after a certain period. However, the recycling of polymeric waste materials has emerged as a prominent topic in research, driven by growing environmental consciousness. Numerous studies indicate that products derived from polymeric waste can be converted into a new polymeric resource in diverse sectors, including organic coatings and regenerative medicine. This review aims to consolidate significant scientific literatures on the recycling PET waste for electrochemical device applications. It also highlights the current challenges in scaling up these processes for industrial application.

Effects of polystyrene, polyethylene, and polypropylene microplastics on the soil-rhizosphere-plant system: Phytotoxicity, enzyme activity, and microbial community

The widespread presence of soil microplastics (MPs) has become a global environmental problem. MPs of different properties (i.e., types, sizes, and concentrations) are present in the environment, while studies about the impact of MPs having different properties are limited. Thus, this study investigated the effects of three common polymers (polystyrene, polyethylene, and polypropylene) with two concentrations (0.01% and 0.1% w/w) on growth and stress response of lettuce (Lactuca sativa L.), soil enzymes, and rhizosphere microbial community. Lettuce growth was inhibited under MPs treatments. Moreover, the antioxidant system, metabolism composition, and phyllosphere microbiome of lettuce leaves was also perturbed. MPs reduced phytase activity and significantly increased dehydrogenase activity. The diversity and structure of rhizosphere microbial community were disturbed by MPs and more sensitive to polystyrene microplastics (PSMPs) and polypropylene microplastics (PPMPs). In general, the results by partial least squares pathway models (PLS-PMs) showed that the presence of MPs influenced the soil-rhizosphere-plant system, which may have essential implications for assessing the environmental risk of MPs.

Microplastics drive community dynamics of periphytic protozoan fauna in marine environments

The pollution of microplastics (MPs) to the marine environment has become a widespread focus of attention. To assess MP-induced ecotoxicity on marine ecosystems, periphytic protozoan communities were used as test organisms and exposed to five concentrations of MPs: 0, 1, 5, 25, and 125 mg l-1. Protozoan samples were collected using microscope slides from coastal waters of the Yellow Sea, northern China. A total of 13 protozoan species were identified and represented different tolerance to MP-induced ecotoxicity. Inhibition effects of MPs on the test protozoan communities were clearly shown in terms of both the species richness and individual abundance and followed linear relationships to MP concentrations. The community patterns were driven by MPs and significantly shifted at concentrations over 5 mg l-1. Our findings demonstrated that MPs may induce the community-level ecotoxic response of periphytic protozoan fauna and followed significant community dynamics. Thus, it is suggested that periphytic protozoan fauna may be used as useful community-based test model organisms for evaluating MP-induced ecotoxicity in marine environments.

Biodegradation of microplastics: Advancement in the strategic approaches towards prevention of its accumulation and harmful effects

Microplastics (MPs) are plastic particles in a size ranging from 1 mm to 5 mm in diameter, and are formed by the breakdown of plastics from different sources. They are emerging environmental pollutants, and pose a great threat to living organisms. Improper disposal, inadequate recycling, and excessive use of plastic led to the accumulation of MP in the environment. The degradation of MP can be done either biotically or abiotically. In view of that, this article discusses the molecular mechanisms that involve bacteria, fungi, and enzymes to degrade the MP polymers as the primary objective. As per as abiotic degradation is concerned, two different modes of MP degradation were discussed in order to justify the effectiveness of biotic degradation. Finally, this review is concluded with the challenges and future perspectives of MP biodegradation based on the existing research gaps. The main objective of this article is to provide the readers with clear insight, and ideas about the recent advancements in MP biodegradation.

Microplastics in Malaysia's Aquatic Environment: Current Overview and Future Perspectives

Microplastic pollution has adversely affected the aquatic ecosystem, living creatures, and human health. Several studies in Malaysia have provided baseline information on the existence of microplastics in surface water, ingestion by marine life and sediment. Also, humans are exposed to microplastic due to consumption of contaminated abiotic and biotic products, such as processed seafood. Nonetheless, knowledge is still scarce among Malaysian on the potential remediation and pollution management of microplastics, which poses a significant challenge to preserve a good environmental status. Green technologies also other alternative to mitigate the contamination of microplastics for sustainable future. Hence, this review aims to provide an overview of microplastic's occurrence, fate, and implications in Malaysia's aquatic environment. Detection of microplastics from the water surface, ingestion by aquatics, and sediment samples are highlighted. Available different treatment processes toward microplastic remediation are also discussed. Additionally, the potential challenges, current perspective for plastic management in Malaysia, as well as green strategies for reducing microplastic contamination are also put forward. The goal of this work is to improve the understanding of the seriousness of microplastic contamination in aquatic environments, thus encouraging key concerns that need to be investigated further.