Entry pathways determined the effects of MPs on sludge anaerobic digestion system: The views of methane production and antibiotic resistance genes fates.

Sludge is one of the primary reservoirs of microplastics (MPs), and the effects of MPs on subsequent sludge treatment raised attention. Given the entry pathways, MPs would exhibit different properties, but the entry pathway-dependent effect of MPs on sludge treatment performance and the fates of antibiotic resistance genes (ARGs), another high-risk emerging contaminant, were seldom documented. Herein, MPs with two predominant entry pathways, including wastewater-derived (WW-derived) and anaerobic digestion-introduced (AD-introduced), were used to investigate the effects on AD performance and ARGs abundances. The results indicated that WW-derived MPs, namely the MPs accumulated in sludge during the wastewater treatment process, exhibited significant inhibition on methane production by 22.8%-71.6%, while the AD-introduced MPs, being introduced in the sludge AD process, slightly increased the methane yield by 4.7%-17.1%. Meanwhile, MPs were responsible for promoting transmission of target ARGs, and polyethylene terephthalate MPs (PET-MPs) showed a greater promotion effect (0.0154-0.0936) than polyamide MPs (PA-MPs) (0.0013-0.0724). Compared to size, entry pathways and types played more vital roles on MPs influences. Investigation on mechanisms based on microbial community structure revealed characteristics (aging degree and types) of MPs determined the differences of AD performance and ARGs fates. WW-derived MPs with longer aging period and higher aging degree would release toxics and decrease the activities of microorganisms, resulting in the negative impact on AD performance. However, AD-introduced MPs with short aging period exhibited marginal impacts on AD performance. Furthermore, the co-occurrent network analysis suggested that the variations of potential host bacteria induced by MPs with different types and aging degree attributed to the dissemination of ARGs. Distinctively from most previous studies, the MPs with different sizes did not show remarkable effects on AD performance and ARGs fates. Our findings benefited the understanding of realistic environmental behavior and effect of MPs with different sources.

Dynamic genetic differentiation drives the widespread structural and functional convergent evolution of snake venom proteinaceous toxins.

BACKGROUND: The explosive radiation and diversification of the advanced snakes (superfamily Colubroidea) was associated with changes in all aspects of the shared venom system. Morphological changes included the partitioning of the mixed ancestral glands into two discrete glands devoted for production of venom or mucous respectively, as well as changes in the location, size and structural elements of the venom-delivering teeth. Evidence also exists for homology among venom gland toxins expressed across the advanced snakes. However, despite the evolutionary novelty of snake venoms, in-depth toxin molecular evolutionary history reconstructions have been mostly limited to those types present in only two front-fanged snake families, Elapidae and Viperidae. To have a broader understanding of toxins shared among extant snakes, here we first sequenced the transcriptomes of eight taxonomically diverse rear-fanged species and four key viperid species and analysed major toxin types shared across the advanced snakes. RESULTS: Transcriptomes were constructed for the following families and species: Colubridae - Helicops leopardinus, Heterodon nasicus, Rhabdophis subminiatus; Homalopsidae - Homalopsis buccata; Lamprophiidae - Malpolon monspessulanus, Psammophis schokari, Psammophis subtaeniatus, Rhamphiophis oxyrhynchus; and Viperidae - Bitis atropos, Pseudocerastes urarachnoides, Tropidolaeumus subannulatus, Vipera transcaucasiana. These sequences were combined with those from available databases of other species in order to facilitate a robust reconstruction of the molecular evolutionary history of the key toxin classes present in the venom of the last common ancestor of the advanced snakes, and thus present across the full diversity of colubroid snake venoms. In addition to differential rates of evolution in toxin classes between the snake lineages, these analyses revealed multiple instances of previously unknown instances of structural and functional convergences. Structural convergences included: the evolution of new cysteines to form heteromeric complexes, such as within kunitz peptides (the beta-bungarotoxin trait evolving on at least two occasions) and within SVMP enzymes (the P-IIId trait evolving on at least three occasions); and the C-terminal tail evolving on two separate occasions within the C-type natriuretic peptides, to create structural and functional analogues of the ANP/BNP tailed condition. Also shown was that the de novo evolution of new post-translationally liberated toxin families within the natriuretic peptide gene propeptide region occurred on at least five occasions, with novel functions ranging from induction of hypotension to post-synaptic neurotoxicity. Functional convergences included the following: multiple occasions of SVMP neofunctionalised in procoagulant venoms into activators of the clotting factors prothrombin and Factor X; multiple instances in procoagulant venoms where kunitz peptides were neofunctionalised into inhibitors of the clot destroying enzyme plasmin, thereby prolonging the half-life of the clots formed by the clotting activating enzymatic toxins; and multiple occasions of kunitz peptides neofunctionalised into neurotoxins acting on presynaptic targets, including twice just within Bungarus venoms. CONCLUSIONS: We found novel convergences in both structural and functional evolution of snake toxins. These results provide a detailed roadmap for future work to elucidate predator-prey evolutionary arms races, ascertain differential clinical pathologies, as well as documenting rich biodiscovery resources for lead compounds in the drug design and discovery pipeline.

Microplastics as Both a Sink and a Source of Bisphenol A in the Marine Environment.

Microplastics were demonstrated to be an environmental sink for hydrophobic organic pollutants, while they can also serve as a potential source of such pollutants. In this study, the sorption and release of bisphenol A in marine water were investigated through laboratory experiments. Sorption and desorption isotherms were developed, and the results reveal that sorption and desorption depend on the crystallinity, elasticity, and hydrophobicity of the polymer concerned. The adsorption and partition of bisphenol A can be quantified using a dual-mode model of the sorption mechanisms. Polyamide and polyurethane were found to exhibit the highest sorption capacity for bisphenol A, and it was almost irreversible, probably due to hydrogen bonding. Polyethylenes and polypropylene exhibited high and reversible sorption without noticeable desorption hysteresis. Glassy polystyrene, poly(vinyl chloride), poly(methyl methacrylate), and poly(ethylene terephthalate) exhibited low sorption capacity and only partial reversibility. Low-density polyethylene and polycarbonate microplastic particles were for the first time proved to be a persistent source releasing bisphenol A into aquatic environments. Salinity, pH, coexisting estrogens, and water chemistry influence the sorption/desorption behaviors to different degrees. Plastic particles can serve as transportation vectors for bisphenol A, which may constitute an ecological risk.

[Treatment of open fracture bone defect of distal femur with antibiotic cement column and bone graft].

OBJECTIVE: To investigate the efficacy of antibiotic cement column combined with iliac bone graft in the treatment of open fracture with bone defect of distal femur. METHODS: From October 2014 to March 2021, 16 patients of open fracture bone defect of distal femur were treated with antibiotic bone cement column and iliac bone graft, including 12 males and 4 females. The age ranged from 28 to 68 years old. There were 11 cases of traffic accident injury, 5 cases of falling injury, 3 cases as Gustilo type Ⅰ, 5 cases as type Ⅱ and 8 cases as type ⅢA. AO classification was used:9 cases of C2 type and 7 cases of C3 type. The time from injury to final bone grafting ranged from 4 to 119 days. The length of bone defect ranged from 2 to10 cm. Fractures healing time, complications and knee function Merchan score were recorded. RESULTS: All the 16 patients were followed up from 9 to 29 months. The incisions of 16 patients healed in one stage without postoperative infection, plate fracture, limb shortening and valgus and varus deformity. The healing time randed from 4 to 10 months . Knee joint function according to the Merchant scoring standard, showed that 8 cases were excellent, 4 cases were good, 3 cases were fair, and 1 case was poor. CONCLUSION: The use of antibiotic bone cement column combined with iliac bone graft in the treatment of open and complex bone defects of distal femur is an effective surgical method to prevent infection, assist fracture reduction, increase fixation strength and significantly reduce the amount of bone grafting.

Insight into the responses of antibiotic resistance genes in microplastic biofilms to zinc oxide nanoparticles and zinc ions pressures in landfill leachate.

Microplastic (MP) biofilms are hotspots of antibiotic resistance genes (ARGs) in landfill environment. MP biofilms in landfill leachate coexist with heavy metals and metallic nanoparticles (NPs) that considered to be the selective agents of ARGs. However, the effects of these selective pressures on ARGs in MP biofilms and their differences in MP-surrounding leachate have not been well understood. Herein, the changes of ARG abundances in MP biofilms and corresponding leachate under zinc oxide (ZnO) NPs and zinc ion (Zn2+) pressures were comparatively analyzed. The presence of ZnO NPs and Zn2+ promoted the enrichment of ARGs in MP biofilms, and the enrichment was more pronounced in ZnO NPs groups. ZnO NPs and especially Zn2+ mainly decreased the abundances of ARGs in leachate. The increase of integron abundances and reactive oxygen species production in MP biofilms implied the enhanced potential for horizontal transfer of ARGs under ZnO NPs and Zn2+ pressures. Meanwhile, the co-occurrence pattern between ARGs and bacterial genera in MP biofilms with more diverse potential ARG hosts was more complex than in leachate, and the enrichment of ARG-hosting bacteria in MP biofilms under ZnO NPs and Zn2+ pressures supported the enrichment of ARGs.

[Effect of circRASA2 targeting miR-543/TRAF6 axis on LPS-induced periodontal ligament cell proliferation and osteogenic differentiation].

PURPOSE: To investigate the possible role of circRASA2 in periodontitis and its potential regulatory mechanism. METHODS: Periodontitis cell model was established by lipopolysaccharide(LPS)-induced periodontal ligament cells(PDLCs). Cell proliferation activity was detected by CCK-8 assay, cell migration ability was detected by Transwell chamber assay, and the expression of osteogenic differentiation-related proteins in cells was detected by Western blot. The target miRNA of circRASA2 and its downstream target genes were predicted using the databases circinteractome and starBase, respectively, and the targeting relationship between the target genes was verified by dual-luciferase reporter gene experiment. GraphPad Prism 8.0 software package was used to analyze the data. RESULTS: circRASA2 was highly expressed in LPS-treated PDLCs cells. LPS-induced PDLCs cell proliferation activity, migration ability and osteogenic differentiation ability decreased, while knockdown of circRASA2 promoted proliferation, migration and osteogenic differentiation ability of PDLCs under LPS treatment. circRASA2 targeted and negatively regulated the expression of miR-543, and overexpression of miR-543 promoted proliferation, migration and osteogenic differentiation of PDLCs under LPS treatment. TRAF6 was a downstream target gene of miR-543, knockdown of circRASA2 down-regulated the expression of TRAF6 through the sponge action of miR-543. Overexpression of TRAF6 reversed the promotion of circRASA2 knockdown on proliferation, migration and osteogenic differentiation of PDLCs. CONCLUSIONS: circRASA2 accelerated the pathological process of periodontitis in vitro through miR-543/TRAF6 axis, and might improve periodontitis by targeting down the expression of circRASA2.

Incomplete degradation of aromatic-aliphatic copolymer leads to proliferation of microplastics and antibiotic resistance genes.

Biodegradable plastics (BDPs) have attracted extensive attention as an alternative to conventional plastics. BDPs could be mineralized by composting, while the quality of compost affected by the presence of BDPs and the residual microplastics (MPs) has not been well evaluated. This study aimed to explore the MPs release potential and environmental implications of commercial BDPs (aromatic-aliphatic copolymer) films in uncontrolled composting. Results showed that the molecular weight of BDPs decreased by >60% within 60 d. However, the non-extracted organic matter and wet-sieving measurements indicated that MPs continuously released and accumulated during regular composting. The average MPs release potential (0.1-5 mm) was 134.6 ± 18.1 particles/mg (BDPs), which resulted in 103-104 particles/g dw in compost. The plastisphere of MPs showed a significantly higher (0.95-16.76 times) abundance of antibiotic resistance genes (ARGs), which resulted in the rising (1.34-2.24 times) of ARGs in compost heaps, in comparison to the control groups. Overall, BDPs promote the spread of ARGs through the selective enrichment of bacteria and horizontal transfer from released MPs. These findings confirmed that BDPs could enhance the release potential of MPs and the dissemination of ARGs, which would promote the holistic understanding and environmental risk of BDPs.

The crystalline structure transition and hydrogen bonds shift determining enhanced enzymatic digestibility of cellulose treated by ultrasonication.

Global energy issue raised the necessity to develop second-generation biofuels, and biorefinery of cellulosic biomass becomes a promising solution. Various pretreatments were used to overcome the cellulose nature of recalcitrance and improve the enzymatic digestibility, but the lack of mechanism understanding hindered the development of efficient and cost-effective technologies of cellulose utilization. Using structure-based analysis, we demonstrate that the improved hydrolysis efficiency caused by ultrasonication was ascribed to the changed cellulose properties rather than the increased dissolubility. Further, isothermal titration calorimetry (ITC) analysis suggested that enzymatic digestion of cellulose is an entropically favored reaction driven by hydrophobic forces other than an enthalpically favored reaction. The changes in cellulose properties and thermodynamic paramenters due to ultrasonication accounted for the improved accessibility. Ultrasonication-treated cellulose showed porous, rough and disordered morphology, accompanying with the loss of crystalline structure. Despite the unaffected unit cell structure, ultrasonication expanded the crystalline lattice by increasing grain sizes and average cross-sectional area, resulting in the transformation from cellulose I to cellulose II, with the decreased crystallinity, better hydrophilicity and increased enzymatic bioaccessibility. Furthermore, FTIR combined with two-dimensional correlation spectroscopy (2D-CoS) verified that the sequential shift of hydroxyl group and intramolecular/intermolecular hydrogen bonds, the functional groups governing cellulose crystal structure and stability, accounted for the ultrasonication-induced transition of cellulose crystalline structure. This study provides a comprehensive picture of cellulose structure and property response caused by mechanistic treatments and will open up avenues to develop novel pretreatments for efficient utilization.

The co-occurrent microplastics and nano-CuO showed antagonistic inhibitory effects on bacterial denitrification: Interaction of pollutants and regulations on functional genes.

The wide occurrence of microplastics (MPs) and nanoparticles resulted in their inevitable coexistence in environment. However, the joint effects of these two types of particulate emerging contaminants on denitrification have seldomly been investigated. Herein, non-biodegradable polyvinyl chloride, polypropylene, polyethylene and biodegradable polyhydroxyalkanoate (PHA) MPs were chosen to perform the co-occurrent effects with nano copper oxide (nano-CuO). Both the nano-CuO and MPs inhibited the denitrification process, and biodegradable PHA-MPs showed severer inhibition than non-biodegradable MPs. However, the presence of MPs significantly alleviated the inhibition of nano-CuO, suggesting an antagonistic effect. Other than MPs decreasing copper ion release from nano-CuO, MPs and nano-CuO formed agglomerations and induced lower levels of oxidative stress compared to individual exposure. Transcriptome analysis indicated that the co-occurrent MPs and nano-CuO induced different regulation on denitrifying genes (e. g. nar and nor) compared to individual ones. Also, the expressions of genes involved in denitrification-associated metabolic pathways, including glycolysis and NADH electron transfer, were down-regulated by nano-CuO or MPs, but exhibiting recovery under the co-occurrent conditions. This study firstly discloses the antagonistic effect of nano-CuO and MPs on environmental process, and these findings will benefit the systematic evaluation of MPs environmental behavior and co-occurrent risk with other pollutants.

Porous (K0.5Na0.5)0.94Li0.06NbO3-polydimethylsiloxane piezoelectric composites harvesting mechanical energy for efficient decomposition of dye wastewater.

Piezoelectricity as a physical property has received great attention due to its excellently functional applications, especially in piezoelectric catalysis and mechanical energy harvesting. To take full advantage of the functions of piezoelectric materials, (K0.5Na0.5)0.94Li0.06NbO3 (KNN6L) piezoelectric powders were compounded with polydimethylsiloxane (PDMS) in this work. The developed KNN6L-PDMS porous piezoelectric composites with flexible and recyclable characteristics could achieve âˆ¼ 91% degradation rate of Rhodamine B (RhB) dye wastewater under mechanical vibration, and the outstanding piezocatalytic activity was still maintained after repeated decomposition multiple times. Besides, the relationship between piezoelectric potential and piezocatalysis was validated by COMSOL simulations. The content of piezoelectric powders played a positive effect on the magnitude of piezoelectric potential generated by the KNN6L-PDMS porous composites. Moreover, the catalytic mechanism was found to be originated by generation of various reactive oxygen species (mainly •O2- and •OH) in water environment as a result of strong piezoelectric effect by the porous composites. The porous piezoelectric composites with flexible and recyclable characteristics exhibited excellent performance in piezoelectric catalysis which has promising applications in the field of environmental remediation.

Size-dependent effects of polystyrene microplastics on anaerobic digestion performance of food waste: Focusing on oxidative stress, microbial community, key metabolic functions.

Polystyrene (PS) microplastics (MPs) are widely existed in food waste (FW) due to the usage of plastic food-packaging. However, the effects and mechanisms of PS MPs with different sizes on anaerobic digestion (AD) performance of FW have not been comprehensively studied yet. Herein, the impacts of different PS MPs sizes (1 mm, 100 µm and 1 µm) with 20, 200 particles/g-TS were investigated. Results showed that 20 particles/g-TS PS MPs decreased cumulative methane production by 1.46-18.11 %, while the higher levels (200 particles/g-TS) significantly inhibited by 9.14-33.08 % (p < 0.05) compared with control group. The inhibiting effects were enhanced as particle size smaller. Physicochemical analysis indicated that MPs prolonged organic matter hydrolysis, weakened the volatile fatty acids metabolism and inhibited methanogenesis-related microorganisms (Synergistetes, Proteiniphilum and Methanosarcina). Small-sized MPs could induce more reactive oxygen species causing cell toxicity and suppressed key enzymes (α-glucoside, protease, acetate kinases and F420) activities, thereby restraining methane production. The analyses of acetyl-CoA synthase and methyl-coenzyme M reductase functional genes illustrated that small-sized MPs negatively affected acetoclastic methanogenesis pathways. Overall, these results provide new insights into the size-dependent effects on AD performance induced by PS MPs.

Size-dependent effects of microplastics on antibiotic resistance genes fate in wastewater treatment systems: The role of changed surface property and microbial assemblages in a continuous exposure mode.

Microplastics (MPs) were continuously transported to wastewater treatment systems and accumulated in sludge constantly, potentially affecting systems function and co-occurrent contaminants fate. However, previous studies were based on acute exposure of MPs, which could not reflect the dynamics of MPs accumulation. Herein, this study firstly raised a more realistic method to evaluate the practical impacts of MPs on systems purification efficiency and antibiotic resistance genes (ARGs) fate. Continuous exposure of MPs did not pose negative effects on nutrients removal, but significantly changed the occurrence patterns of ARGs. ARGs abundances increased by 42.8 % and 54.3 % when exposed to millimeter-size MPs (mm-MPs) polyamide and polyethylene terephthalate, but increased by 31.3 % and 39.4 % to micron-size MPs (µm-MPs), respectively. Thus, mm-MPs posed severer effects on ARGs than µm-MPs. Further, mm-MPs surface properties were obviously altered after long-term exposure (higher specific surface area and O-containing species), which benefited microbes attachment. More importantly, more taxa linkages and changed topological properties (higher average degree and average weight) of co-occurrent network were observed in sludge with mm-MPs than with µm-MPs, as well as totally different potential host bacteria of ARGs. Rough surface of MPs and closer relations between ARGs and bacteria taxa contributed to the propagation of ARGs, which accounted for the observed higher ARGs abundances of mm-MPs. This study demonstrated that long-term accumulation of MPs in wastewater treatment systems affected ARGs fate, and mm-MPs caused severer risk due to their enrichment of ARGs. The results would promote the understanding of MPs real environmental behavior and influences.

Distinguishing removal and regrowth potential of antibiotic resistance genes and antibiotic resistant bacteria on microplastics and in leachate after chlorination or Fenton oxidation.

The prevalence of antibiotic resistance, as well as microplastics (MPs) as vectors for antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) has attracting growing attention. However, the fate of ARB/ARGs on MPs treated by chlorination and Fenton oxidation were poorly understood. Herein, the removal and regrowth of ARGs/ARB on MPs and in MPs-surrounding landfill leachate (an important reservoir of MPs and ARGs) after chlorination and Fenton oxidation were comparatively analyzed. Target ARGs on MPs were reduced obviously less than that in leachate, with the largest percentages reduction of 34.0-46.3% vs. 54.3-77.6% after chlorination and 92.1-97.3% vs. > 99.9% after Fenton oxidation, and similar removal patterns were observed for ARB. Moreover, a considerable regrowth of ARGs/ARB in leachate were found after 48 h of storage at the end of chlorination (5, 10, 20 and 50 mg/L), and a greater regrowth of ARGs and ARB occurred on MPs with up to 17 and 139 fold, respectively. In contrast, Fenton oxidation achieved a reduced regrowth of target ARGs/ARB. These findings indicated that the removal of ARGs/ARB on MPs were more difficult than that in leachate, and ARGs/ARB in leachate and especially on MPs exhibited a considerable potential for rapid regrowth after chlorination.

Calcium Silicate Whiskers-Enforced Poly(Ether-Ether-Ketone) Composites with Improved Mechanical Properties and Biological Activities for Bearing Bone Reconstruction.

Poly (ether-ether-ketone) (PEEK) displays promising potential application in bone tissue repair and orthopedic surgery due to its good biocompatibility and chemical stability. However, the bio-inertness and poor mechanical strength of PEEK greatly limit its application in load-bearing bones. In this study, calcium silicate whiskers (CSws) are synthesized and then compounded with PEEK to fabricate the PEEK/CSw composites with excellent mechanical properties, biological activity. Compared with PEEK, the PEEK/CSw composites exhibited higher hydrophilicity and ability to deposit hydroxyapatite on the surface. CSws are evenly dispersed in the PEEK matrix at 10 wt% content and the mechanical strength of the PEEK/CSw composite is ≈96.9 ± 2.4 MPa, 136.3 ± 2.4 MPa, and 266.0 ± 3.2 MPa, corresponding to tensile strength, compressive strength, and bending strength, respectively, which is 20%, 18%, and 52% higher than that of pure PEEK. The composites improve the adhesion, proliferation, and osteogenic differentiation of BMSCs. Furthermore, PEEK/CSw composite remarkably improves bone formation and osteointegration, which has higher bone repair capacity than PEEK. These results demonstrate that the PEEK/CSw scaffolds display superior abilities to integrate with the host bone and promising potential in the field of load bearing bone repair.

Selective enrichment of antibiotic resistance genes and pathogens on polystyrene microplastics in landfill leachate.

Landfill leachate is an important reservoir of antibiotic resistance genes (ARGs) and microplastics (MPs). However, the enrichment characteristics of ARGs on MPs and the effect of MPs' presence on ARGs in surrounding leachates are little studied. Therefore, we investigated the differences of ARGs, mobile genetic elements (MGEs), bacterial communities and pathogens on polystyrene MPs, in MPs-surrounding leachate and in control (leachate with the absence of MPs). The results revealed that ARGs were selectively enriched on MPs, which was similar in three types of leachate environments. The genes strB and blaTEM were maximally enriched and mefA, ermB, tetM and tetQ were slightly enriched on MPs, and the degree of ARGs enrichment increased with time during the 60 days of the experiment. Furthermore, compared to the leachate, MPs were observed to have the higher abundances of MGEs and distinct bacterial communities, both of which were closely associated with ARGs on MPs. Pathogens were distinct and more abundant on MPs compared to that in leachate, and 11 pathogens were identified as potential hosts for ARGs on MPs. Additionally, the presence of MPs (500 mg/L) induced few changes in ARGs' abundances, MGEs' abundances and bacterial communities in MP-surrounding leachate within 60 days. Overall, this study suggested that MPs could selectively enrich ARGs and pathogens from the surrounding environments, which promoted the understanding of the combined pollution properties of MPs and ARGs.

Occurrence, influence and removal strategies of mycotoxins, antibiotics and microplastics in anaerobic digestion treating food waste and co-digestive biosolids: A critical review.

Food waste anaerobic digestion (FWAD) can be assisted with the co-digestion of manures, agricultural waste, and sewage sludge. Nevertheless, contaminants like mycotoxins, antibiotics, and microplastics (MPs) could be introduced and negatively affect the AD system. Over 180 literatures involved the occurrence, influence and removal strategies of these three types of pollutants in AD were summarized in this review. Aflatoxin B1(AFB1) as the most concerned mycotoxins were poorly degraded and brought about inhibitions in short-term. Considering methanogenesis inhibition and occurrence concentration, the risk of oxytetracycline and norfloxacin were identified as priority among antibiotics. Leaching toxic additives from MPs could be responsible for the AD inhibition, while their materials and sizes could also prolong the acidification and methanation processes in FWAD. Strategies of bioaugmentation technologies and bioreactors to enhance the removal were suggested. Perspectives were provided for a better understanding of the fates of reviewed contaminants and their elimination in FWAD systems.

Microplastics act as vectors for antibiotic resistance genes in landfill leachate: The enhanced roles of the long-term aging process.

Microplastics (MPs) are found to be ubiquitous and serve as vectors for other contaminants, and the inevitable aging process changes MP properties and fates. However, whether the MPs in aging process affects the fates of antibiotic resistance gene (ARGs) in aquatic environments is poorly understood. Herein, the physicochemical property alteration of MPs being aged in landfill leachate, an important reservoir of MPs and ARGs, was investigated, and microbial community evolution and ARGs occurrence of MP surface during the aging process were analyzed. Aging process remarkably altered surface properties, including increasing specific surface areas, causing the formation of oxygen-containing groups, and changing surface morphology, which further increased the probability of microbial colonization. The bacterial assemblage on MPs showed higher biofilm-forming and pathogenic potential compared to leachate. ARGs quantification results suggested that MPs exhibited selective enrichment for ARGs in a ratio of 5.7-103 folds, and the aging process enhanced the enrichment potential. Further co-occurrence networks suggested that the existence of non-random, closer and more stable ARGs-bacterial taxa relations on MP surface affected the ARG transmission. The study of ARG partitioning on MPs indicated that extracellular DNA was a nonnegligible reservoir of ARGs attached on MP surface, and that biofilm bacterial community influenced ARGs partitioning pattern during the aging process. This study confirmed that the aging process could enhance the potential of MPs as vectors for ARGs, which would promote the holistic understanding of MP behavior and risk in natural environments.

Distribution and removal characteristics of microplastics in different processes of the leachate treatment system.

Microplastics (MPs) in environments are widely concerned in recent years due to the widely occurrence and potential risk to environments. With a large amount of plastic waste discarded into the landfills, leachate generated from landfills was found to be an important pollution source of MPs. However, the removal efficiency and characteristics of MPs in leachate treatment system were not clear. In this study, the concentration variation and the removal performance of MPs in leachate treatment system with the process of pretreatment + biotreatment + advanced treatment were investigated. The results showed that 58.33% of MPs were removed during the leachate treatment process. The Ultrafiltration had the highest efficiency of removing MPs, but the advanced treatment technologies (Nanofiltration and Reverse Osmosis) did not contribute to the removal of MPs. Furthermore, the removal performance of MPs in leachate treatment process was determined by MPs properties, such as size, shape and polymer type. The whole leachate treatment process had higher removal efficiencies for particle MPs compared to fiber MPs, and only 50% of fiber MPs were removed in biological treatment and advanced treatment. Ultrafiltration had better removal effect on microplastics with the size of less than 1 mm, and MPs less than 0.5 mm were almost removed by advanced treatment but accumulated in the sludge with the abundance of 0.893 ± 0.252 items/g. The results showed that a considerable amount of MPs (106 items/day) discharged with the effluent (3200 t/d), and most removed MPs from leachate accumulated in sludge, which would cause potential risk to the environments.

Edible coating based on beeswax-in-water Pickering emulsion stabilized by cellulose nanofibrils and carboxymethyl chitosan.

In this work, novel edible coating films based on beeswax-in-water (O/W) Pickering emulsions had been investigated. The Pickering emulsions were stabilized with cellulose nanofibrils (CNFs)/carboxymethyl chitosan (CCS). The emulsions with a droplet diameter of around 10 µm had uniform particle size distribution, and the creaming stability was improved with the increasing the contents of CNFs in the complexes, rheological analysis demonstrated that the Pickering emulsions had an elastic gel-like network. Furthermore, free-standing films were obtained when the emulsions were dried at ambient condition, the tensile strength of the coating films could be 5.0 MPa at a strain of 2.2%, and the water vapor permeability (WVP) value was lower than 2 × 10-7 g∙h-1∙m-1∙Pa-1. Moreover, the coating films could inhibit the growth of typical spoilage organisms such as S. aureus or E. coli, it indicated that the coatings films would have promising applications in antiseptic and fresh keeping for berry fruits.

Prevalence of microplastics in animal-based traditional medicinal materials: Widespread pollution in terrestrial environments.

Microplastics (MPs) pollution is an emerging environmental and health concern. MPs have been extensively observed in the aquatic environment, yet rarely investigated in the terrestrial ecosystem, especially in relation to health risks. To evaluate potential MPs pollution in land-dwelling animal medicine materials, we collected 20 types of small animal-based medicinal materials and 10 types of available fresh terrestrial animals from eight different regions in China. MPs were found in all medicinal materials with an average incidence rate of 94.67%. The abundance of MPs was in the range of 1.80 ± 0.38 to 7.80 ± 0.83 items/individual or 1.59 ± 0.33 to 43.56 ± 9.22 items/g (dry weight), with polymer distribution by polyethylene terephthalate (40.45%), rayon (30.64%), polyethylene (10.11%), nylon (7.35%), polypropylene (5.93%), and polyvinyl chloride (5.52%). The majority of MPs were microfibers (84.68%), with 15.32% of fragments. Moreover, MPs were directly observed in the intestine, detected in all ten types of fresh medicinal animals with the abundance of 0.83 ± 0.35 to 3.42 ± 0.46 items/individual. Furthermore, significant positive correlations (R: 0.32-0.99, p < 0.05) of MPs characteristics were found between medicinal materials and fresh animals, including shape, size, color, and polymer distribution of MPs. The results support that MPs in the medicinal materials were likely derived from living animals. This study demonstrates the prevalence of MPs in animal-based, traditional medicinal materials, and also suggests widespread MPs pollution in terrestrial environments and latent health risks.