Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 1.099
Filter
1.
BMC Plant Biol ; 24(1): 593, 2024 Jun 24.
Article in English | MEDLINE | ID: mdl-38910247

ABSTRACT

BACKGROUND: Long-term continuous cropping has resulted in the frequent occurrence of fusarium wilt of watermelon (Citrullus lanatus). AMF inoculation can alleviate the continuous cropping barrier and reduce the incidence of fusarium wilt of watermelon. Our previous study found that the root exudates of mycorrhizal watermelon can enhance watermelon resistance to this disorder. It is necessary to further isolate and identify the specific compounds in root exudates of mycorrhizal watermelon and explore their control effects on fusarium wilt of continuous cropping watermelon. RESULT: The results of this study showed that the root system of watermelon seedlings inoculated with AMF (Funneliformis mosseae or Glomus versiforme) secreted diisooctyl phthalate (A) and dibutyl phthalate (B). Compared with water treatment, treatment with 0.1 ml/L (A1, B1), 0.5 ml/L (A2, B2) and 1 ml/L (A3, B3) of A or B significantly increased soil enzyme activities, the numbers of bacteria and actinomycetes, and the bacteria/fungi ratio in the rhizosphere. Furthermore, the Disease indexes (DI) of A1 and B3 were 25% and 20%, respectively, while the prevention and control effects (PCE) were 68.8% and 75%, respectively. In addition, diisooctyl phthalate or dibutyl phthalate increased the proportions of Gemmatimonadetes, Chloroflexi, and Acidobacteria in the rhizosphere of continuous cropping watermelon, and decreased the proportions of Proteobacteria and Firmicutes, with Novosphingobium, Kaistobacter, Bacillus, and Acinetobacter as the predominant bacteria. Compared with the water treatment, the abundance of Neosphingosaceae, Kateybacterium and Bacillus in the A1 group was increased by 7.33, 2.14 and 2.18 times, respectively, while that in the B2 group was increased by 60.05%, 80.24% and 1 time, respectively. In addition, exogenous diisooctyl phthalate and dibutyl phthalate were shown to promote growth parameters (vine length, stem diameter, fresh weight and dry weight) and antioxidant enzyme system activities (SOD, POD and CAT) of continuous cropping watermelon. CONCLUSION: Lower watermelon fusarium wilt incidence in mycorrhizal watermelons was associated with phthalate secretion in watermelons after AMF inoculation. Exogenous diisooctyl phthalate and dibutyl phthalate could alleviate the continuous cropping disorder of watermelon, reduce the incidence of fusarium wilt, and promote the growth of watermelon by increasing the enzyme activities and the proportion of beneficial bacteria in rhizosphere soil. In addition, the low concentration of phthalate diisooctyl and high concentration of phthalic acid dibutyl works best. Therefore, a certain concentration of phthalates in the soil can help alleviate continuous cropping obstacles.


Subject(s)
Citrullus , Fusarium , Mycorrhizae , Phthalic Acids , Plant Diseases , Plant Roots , Soil Microbiology , Citrullus/microbiology , Citrullus/growth & development , Mycorrhizae/physiology , Plant Diseases/microbiology , Plant Diseases/prevention & control , Plant Roots/microbiology , Plant Roots/growth & development , Phthalic Acids/metabolism , Bacteria/isolation & purification , Bacteria/drug effects , Soil/chemistry , Rhizosphere
2.
World J Microbiol Biotechnol ; 40(8): 247, 2024 Jun 21.
Article in English | MEDLINE | ID: mdl-38904858

ABSTRACT

Phthalate isomers are key intermediates in the biodegradation of pollutants including waste polyethylene terephthalate (PET) plastics and plasticizers. So far, an increasing number of phthalate isomer-degrading strains have been isolated, and their degradation pathways show significant diversity. In this paper, we comprehensively review the current status of research on the degrading bacteria, degradation characteristics, aerobic and anaerobic degradation pathways, and degradation genes (clusters) of phthalate isomers, and discuss the current shortcomings and challenges. Moreover, the degradation process of phthalate isomers produces many important aromatic precursor molecules, which can be used to produce higher-value derivative chemicals, and the modification of their degradation pathways holds good prospects. Therefore, this review also highlights the current progress made in modifying the phthalate isomer degradation pathway and explores its potential for high-value applications.


Subject(s)
Bacteria , Biodegradation, Environmental , Phthalic Acids , Phthalic Acids/metabolism , Bacteria/metabolism , Bacteria/genetics , Bacteria/classification , Isomerism , Plasticizers/metabolism , Environmental Pollutants/metabolism , Metabolic Networks and Pathways , Polyethylene Terephthalates/metabolism , Polyethylene Terephthalates/chemistry
3.
Biochemistry ; 63(13): 1663-1673, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38885634

ABSTRACT

The mono(2-hydroxyethyl) terephthalate hydrolase (MHETase) from Ideonella sakaiensis carries out the second step in the enzymatic depolymerization of poly(ethylene terephthalate) (PET) plastic into the monomers terephthalic acid (TPA) and ethylene glycol (EG). Despite its potential industrial and environmental applications, poor recombinant expression of MHETase has been an obstacle to its industrial application. To overcome this barrier, we developed an assay allowing for the medium-throughput quantification of MHETase activity in cell lysates and whole-cell suspensions, which allowed us to screen a library of engineered variants. Using consensus design, we generated several improved variants that exhibit over 10-fold greater whole-cell activity than wild-type (WT) MHETase. This is revealed to be largely due to increased soluble expression, which biochemical and structural analysis indicates is due to improved protein folding.


Subject(s)
Burkholderiales , Burkholderiales/enzymology , Burkholderiales/genetics , Burkholderiales/metabolism , Phthalic Acids/metabolism , Phthalic Acids/chemistry , Hydrolases/metabolism , Hydrolases/genetics , Hydrolases/chemistry , Solubility , Polyethylene Terephthalates/metabolism , Polyethylene Terephthalates/chemistry , Recombinant Proteins/metabolism , Recombinant Proteins/genetics , Recombinant Proteins/chemistry , Protein Engineering/methods , Protein Folding , Escherichia coli/genetics , Escherichia coli/metabolism , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/chemistry , Models, Molecular
4.
J Hazard Mater ; 474: 134743, 2024 Aug 05.
Article in English | MEDLINE | ID: mdl-38852244

ABSTRACT

Phthalate esters (PAEs), as a major plasticizer with multi-biotoxicity, are frequently detected in marine environments, and potentially affecting the survival of aquatic organisms. In the study, three typical PAEs (dimethyl phthalate [DMP], dibutyl phthalate [DBP] and di(2-ethylhexyl) phthalate [DEHP]) were selected to investigate the accumulation patterns and ecotoxicological effects on Mytilus coruscus (M. coruscus). In M. coruscus, the accumulation was DEHP>DBP>DMP, and the bioaccumulation in tissues was digestive glands>gills>gonads>muscles. Meanwhile, the activities of superoxide dismutase (SOD) and catalase (CAT) showed an activation-decrease-activation trend of stress, with more pronounced concentration effects. Glutathione reductase (GSH) activity was significantly increased, and its expression was more sensitive to be induced at an early stage. The metabolic profiles of the gonads, digestive glands and muscle tissues were significantly altered, and DEHP had a greater effect on the metabolic profiles of M. coruscus, with the strongest interference. PAEs stress for 7 d significantly altered the volatile components of M. coruscus, with potential implications for their nutritional value. This study provides a biochemical, metabolomic, and nutritional analysis of DMP, DBP, and DEHP toxic effects on M. coruscus from a multidimensional perspective, which provides support for ecotoxicological studies of PAEs on marine organisms. ENVIRONMENTAL IMPLICATION: Phthalate esters (PAEs), synthetic compounds from phthalic acid, are widespread in the environment, household products, aquatic plants, animals, and crops, posing a significant threat to human health. However, the majority of toxicological studies examining the effects of PAEs on aquatic organisms primarily focus on non-economic model organisms like algae and zebrafish. Relatively fewer studies have been conducted on marine organisms, particularly economically important shellfish. So, this study is innovative and necessary. This study provides a biochemical, metabolomic, and nutritional analysis of DMP, DBP, and DEHP toxic effects on mussels, and supports the ecotoxicology of PAEs on marine organisms.


Subject(s)
Mytilus , Phthalic Acids , Plasticizers , Water Pollutants, Chemical , Animals , Phthalic Acids/toxicity , Phthalic Acids/metabolism , Mytilus/drug effects , Mytilus/metabolism , Water Pollutants, Chemical/toxicity , Water Pollutants, Chemical/metabolism , Plasticizers/toxicity , Plasticizers/metabolism , Superoxide Dismutase/metabolism , Antioxidants/metabolism , Diethylhexyl Phthalate/toxicity , Diethylhexyl Phthalate/metabolism , Catalase/metabolism , Dibutyl Phthalate/toxicity , Dibutyl Phthalate/metabolism , Glutathione Reductase/metabolism , Gonads/drug effects , Gonads/metabolism , Esters/metabolism , Esters/toxicity , Oxidative Stress/drug effects
5.
J Hazard Mater ; 474: 134776, 2024 Aug 05.
Article in English | MEDLINE | ID: mdl-38852255

ABSTRACT

Phthalate esters (PAEs) are widely used as plasticizers and cause serious complex pollution problem in environment. Thus, strains with efficient ability to simultaneously degrade various PAEs are required. In this study, a newly isolated strain Rhodococcus sp. AH-ZY2 can degrade 500 mg/L Di-n-octyl phthalate completely within 16 h and other 500 mg/L PAEs almost completely within 48 h at 37 °C, 180 rpm, and 2 % (v/v) inoculum size of cultures with a OD600 of 0.8. OD600 = 0.8, 2 % (v/v). Twenty genes in its genome were annotated as potential esterase and four of them (3963, 4547, 5294 and 5359) were heterogeneously expressed and characterized. Esterase 3963 and 4547 is a type I PAEs esterase that hydrolyzes PAEs to phthalate monoesters. Esterase 5294 is a type II PAEs esterase that hydrolyzes phthalate monoesters to phthalate acid (PA). Esterase 5359 is a type III PAEs esterase that simultaneously degrades various PAEs to PA. Molecular docking results of 5359 suggested that the size and indiscriminate binding feature of spacious substrate binding pocket may contribute to its substrate versatility. AH-ZY2 is a potential strain for efficient remediation of PAEs complex pollution in environment. It is first to report an esterase that can efficiently degrade mixed various PAEs.


Subject(s)
Biodegradation, Environmental , Esterases , Esters , Molecular Docking Simulation , Phthalic Acids , Rhodococcus , Rhodococcus/metabolism , Rhodococcus/genetics , Rhodococcus/enzymology , Phthalic Acids/metabolism , Phthalic Acids/chemistry , Esterases/metabolism , Esterases/genetics , Esters/metabolism , Esters/chemistry , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Plasticizers/metabolism
6.
J Hazard Mater ; 474: 134797, 2024 Aug 05.
Article in English | MEDLINE | ID: mdl-38865921

ABSTRACT

Poly(butylene adipate-co-terephthalate) (PBAT) is widely utilized in the production of food packaging and mulch films. Its extensive application has contributed significantly to global solid waste, posing numerous environmental challenges. Recently, enzymatic recycling has emerged as a promising eco-friendly solution for the management of plastic waste. Here, we systematically investigate the depolymerization mechanism of PBAT catalyzed by cutinase TfCutSI with molecular docking, molecular dynamics simulations, and quantum mechanics/molecular mechanics calculations. Although the binding affinities for acid ester and terephthalic acid ester bonds are similar, a regioselective depolymerization mechanism and a "chain-length" effect on regioselectivity were proposed and evidenced. The regioselectivity is highly associated with specific structural parameters, namely Substrate@O4-Met@H7 and Substrate@C1-Ser@O1 distances. Notably, the binding mode of BTa captured by X-ray crystallography does not facilitate subsequent depolymerization. Instead, a previously unanticipated binding mode, predicted through computational analysis, is confirmed to play a crucial role in BTa depolymerization. This finding proves the critical role of computational modelling in refining experimental results. Furthermore, our results revealed that both the hydrogen bond network and enzyme's intrinsic electric field are instrumental in the formation of the final product. In summary, these novel molecular insights into the PBAT depolymerization mechanism offer a fundamental basis for enzyme engineering to enhance industrial plastic recycling.


Subject(s)
Molecular Docking Simulation , Polyesters , Polymerization , Polyesters/chemistry , Polyesters/metabolism , Molecular Dynamics Simulation , Phthalic Acids/chemistry , Phthalic Acids/metabolism , Stereoisomerism , Carboxylic Ester Hydrolases
7.
BMC Oral Health ; 24(1): 541, 2024 May 08.
Article in English | MEDLINE | ID: mdl-38720320

ABSTRACT

BACKGROUND: Widespread exposure to phthalates may raise the probability of various diseases. However, the association of phthalate metabolites with periodontitis remains unclear. METHODS: Totally 3402 participants from the National Health and Nutrition Examination Survey (NHANES) 2009 to 2014 cycles were enrolled in the cross-sectional investigation. We utilized weighted logistic regression to evaluate the association of ten phthalate metabolites with periodontitis. Restricted cubic spline analysis was applied to investigate potential nonlinear relationships. RESULTS: The weighted prevalence of periodontitis in the study was 42.37%. A one standard deviation (SD) rise in log-transformed levels of mono-2-ethyl-5-carboxypenty phthalate (MECPP), mono-n-butyl phthalate (MnBP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-isobutyl phthalate (MiBP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-benzyl phthalate (MBzP) was associated with higher odds of periodontitis, with odds ratios (95% confidence intervals) of 1.08 (1.02-1.14), 1.07 (1.02-1.11), 1.10 (1.05-1.15), 1.05 (1.01-1.09), 1.09 (1.04-1.14), and 1.08 (1.03-1.13), respectively. Individuals with the highest quartile concentrations of MECPP, MnBP, MEHHP, MEOHP, and MBzP were associated with 32%, 20%, 30%, 25%, and 26% increased odds of periodontitis, respectively, compared to those with the lowest quartile. Additionally, mono-(3-carboxypropyl) phthalate (MCPP) demonstrated an interesting inverted J-shaped relationship with periodontitis. CONCLUSIONS: The findings indicate an association of certain phthalate metabolites with periodontitis among US adults.


Subject(s)
Nutrition Surveys , Periodontitis , Phthalic Acids , Humans , Phthalic Acids/metabolism , Female , Cross-Sectional Studies , Male , Adult , Periodontitis/epidemiology , Periodontitis/metabolism , Middle Aged , United States/epidemiology , Prevalence , Young Adult
8.
Environ Pollut ; 355: 124217, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-38797346

ABSTRACT

Although di(2-ethylhexyl) terephthalate (DOTP) is being widely adopted as a non-phthalate plasticizer, existing research primarily focuses on human and rat toxicity. This leaves a significant gap in our understanding of their impact on microbial communities. This study assessed the biodegradation and toxicity of DOTP on microbes, focusing on its impact on biofilms and microbial metabolism using Rhodococcus ruber as a representative bacterial strain. DOTP is commonly found in mass fractions between 0.6 and 20% v/v in various soft plastic products. This study used polyvinyl chloride films (PVC) with varying DOTP concentrations (range 1-10% v/v) as a surface for analysis of biofilm growth. Cell viability and bacterial stress responses were tested using LIVE/DEAD™ BacLight™ Bacterial Viability Kit and by the detection of reactive oxygen species using CellROX™ Green Reagent, respectively. An increase in the volume of dead cells (in the plastisphere biofilm) was observed with increasing DOTP concentrations in experiments using PVC films, indicating the potential negative impact of DOTP on microbial communities. Even at a relatively low concentration of DOTP (1%), signs of stress in the microbes were noticed, while concentrations above 5% compromised their ability to survive. This research provides a new understanding of the environmental impacts of alternative plasticizers, prompting the need for additional research into their wider effects on both the environment and human health.


Subject(s)
Biodegradation, Environmental , Biofilms , Phthalic Acids , Plasticizers , Reactive Oxygen Species , Plasticizers/toxicity , Biofilms/drug effects , Reactive Oxygen Species/metabolism , Phthalic Acids/toxicity , Phthalic Acids/metabolism , Rhodococcus/metabolism , Rhodococcus/drug effects , Polyvinyl Chloride/toxicity , Diethylhexyl Phthalate/toxicity
9.
J Hazard Mater ; 472: 134493, 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-38696960

ABSTRACT

Environmental pollution caused by plastic waste has become global problem that needs to be considered urgently. In the pursuit of a circular plastic economy, biodegradation provides an attractive strategy for managing plastic wastes, whereas effective plastic-degrading microbes and enzymes are required. In this study, we report that Blastobotrys sp. G-9 isolated from discarded plastic in landfills is capable of depolymerizing polyurethanes (PU) and poly (butylene adipate-co-terephthalate) (PBAT). Strain G-9 degrades up to 60% of PU foam after 21 days of incubation at 28 â„ƒ by breaking down carbonyl groups via secretory hydrolase as confirmed by structural characterization of plastics and degradation products identification. Within the supernatant of strain G-9, we identify a novel cutinase BaCut1, belonging to the esterase family, that can reproduce the same effect. BaCut1 demonstrates efficient degradation toward commercial polyester plastics PU foam (0.5 mg enzyme/25 mg plastic) and agricultural film PBAT (0.5 mg enzyme/10 mg plastic) with 50% and 18% weight loss at 37 â„ƒ for 48 h, respectively. BaCut1 hydrolyzes PU into adipic acid as a major end-product with 42.9% recovery via ester bond cleavage, and visible biodegradation is also identified from PBAT, which is a beneficial feature for future recycling economy. Molecular docking, along with products distribution, elucidates a special substrate-binding modes of BaCut1 with plastic substrate analogue. BaCut1-mediated polyester plastic degradation offers an alternative approach for managing PU plastic wastes through possible bio-recycling.


Subject(s)
Biodegradation, Environmental , Carboxylic Ester Hydrolases , Polyurethanes , Recycling , Polyurethanes/chemistry , Carboxylic Ester Hydrolases/metabolism , Carboxylic Ester Hydrolases/chemistry , Burkholderiales/enzymology , Burkholderiales/metabolism , Phthalic Acids/metabolism , Phthalic Acids/chemistry , Plastics/chemistry , Plastics/metabolism , Bacterial Proteins/metabolism , Bacterial Proteins/chemistry , Polyesters
10.
Arch Microbiol ; 206(6): 254, 2024 May 10.
Article in English | MEDLINE | ID: mdl-38727835

ABSTRACT

Phthalic acid esters (PAEs) are human made chemicals widely used as plasticizers to enhance the flexibility of plastic products. Due to the lack of chemical bonding between phthalates and plastics, these materials can easily enter the environment. Deleterious effects caused by this chemo-pollutant have drawn the attention of the scientific community to remediate them from different ecosystem. In this context, many bacterial strains have been reported across different habitats and Sphingobium yanoikuyae strain P4 is among the few psychrotolerant bacterial species reported to biodegrade simple and complex phthalates. In the present study, biodegradation of three structurally different PAEs viz., diethyl phthalate (DEP), di-isobutyl phthalate (DIBP), and butyl benzyl phthalate (BBP) have been investigated by the strain P4. Quantitative analyses through High-performance liquid chromatography (HPLC) revealed that the bacterium completely degraded 1 g/L of DEP, DIBP, and BBP supplemented individually in minimal media pH 7.0 within 72, 54, and 120 h of incubation, respectively, at 28 °C and under shake culture condition (180 rpm). In addition, the strain could grow in minimal media supplemented individually with up to 3 g/L of DEP and 10.0 g/L of DIBP and BBP at 28 °C and pH 7.0. The strain also could grow in metabolites resulting from biodegradation of DEP, DIBP, and BBP, viz. n-butanol, isobutanol, butyric acid, ethanol, benzyl alcohol, benzoic acid, phthalic acid, and protocatechuic acid. Furthermore, phthalic acid and protocatechuic acid were also detected as degradation pathway metabolites of DEP and DIBP by HPLC, which gave an initial idea about the biodegradation pathway(s) of these phthalates.


Subject(s)
Biodegradation, Environmental , Phthalic Acids , Sphingomonadaceae , Phthalic Acids/metabolism , Sphingomonadaceae/metabolism , Sphingomonadaceae/genetics , Dibutyl Phthalate/metabolism , Plasticizers/metabolism , Chromatography, High Pressure Liquid , Hydroxybenzoates/metabolism
11.
J Hazard Mater ; 473: 134554, 2024 Jul 15.
Article in English | MEDLINE | ID: mdl-38759407

ABSTRACT

The widely existed plastic additives plasticizers in organic wastes possibly pose negative influences on anaerobic digestion (AD) performance, the direct evidence about the effects of plasticizers on AD performance is still lacking. This study evaluated the influencing mechanism of two typical plasticizers bisphenol A (BPA) and dioctyl phthalate on the whole AD process. Results indicated that plasticizers addition inhibited methane production, and the inhibiting effects were reinforced with the increase of concentration. By contrast, 50 mg/L BPA exhibited the strongest inhibition on methane production. Physicochemical analysis showed plasticizers inhibited the metabolism efficiency of soluble polysaccharide and volatile fatty acids. Microbial communities analyses suggested that plasticizers inhibited the direct interspecies electron transfer participators of methanogenic archaea (especially Methanosarcina) and syntrophic bacteria. Furthermore, plasticizers inhibited the methane metabolisms, key coenzymes (CoB, CoM, CoF420 and methanofuran) biosynthesis and the metabolisms of major organic matters. This study shed light on the effects of plasticizers on AD performance and provided new insights for assessing the influences of plasticizers or plastic additives on the disposal of organic wastes.


Subject(s)
Benzhydryl Compounds , Methane , Phenols , Plasticizers , Anaerobiosis , Plasticizers/metabolism , Methane/metabolism , Benzhydryl Compounds/metabolism , Phenols/metabolism , Fatty Acids, Volatile/metabolism , Bacteria/metabolism , Bacteria/drug effects , Bioreactors , Refuse Disposal/methods , Phthalic Acids/metabolism , Food , Food Loss and Waste
12.
Chemosphere ; 359: 142322, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38761823

ABSTRACT

Selecting and cultivating low-accumulating crop varieties (LACVs) is the most effective strategy for the safe utilization of di-(2-ethylhexyl) phthalate (DEHP)-contaminated soils, promoting cleaner agricultural production. However, the adsorption-absorption-translocation mechanisms of DEHP along the root-shoot axis remains a formidable challenge to be solved, especially for the research and application of LACV, which are rarely reported. Here, systematic analyses of the root surface ad/desorption, root apexes longitudinal allocation, uptake and translocation pathway of DEHP in LACV were investigated compared with those in a high-accumulating crop variety (HACV) in terms of the root-shoot axis. Results indicated that DEHP adsorption was enhanced in HACV by root properties, elemental composition and functional groups, but the desorption of DEHP was greater in LACV than HACV. The migration of DEHP across the root surface was controlled by the longitudinal partitioning process mediated by root tips, where more DEHP accumulated in the root cap and meristem of LACV due to greater cell proliferation. Furthermore, the longitudinal translocation of DEHP in LACV was reduced, as evidenced by an increased proportion of DEHP in the root apoplast. The symplastic uptake and xylem translocation of DEHP were suppressed more effectively in LACV than HACV, because DEHP translocation in LACV required more energy, binding sites and transpiration. These results revealed the multifaceted regulation of DEHP accumulation in different choysum (Brassica parachinensis L.) varieties and quantified the pivotal regulatory processes integral to LACV formation.


Subject(s)
Plant Roots , Soil Pollutants , Vegetables , Plant Roots/metabolism , Soil Pollutants/metabolism , Soil Pollutants/analysis , Vegetables/metabolism , Soil/chemistry , Phthalic Acids/metabolism , Diethylhexyl Phthalate/metabolism , Adsorption
13.
J Hazard Mater ; 472: 134593, 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-38749249

ABSTRACT

Due to the lack of research on the co-effects of microplastics and trace metals in the environment on nitrogen cycling-related functional microorganisms, the occurrence of microplastics and one of their plasticisers, phthalate esters, as well as trace metals, were determined in soils and river sediments in the Qinghai-Tibet Plateau. Relationship between microplastics and phthalate esters in the area was determined; the co-effects of these potentially toxic materials, and key factors and pathways affecting nitrogen functions were further explored. Significant correlations between fibre- and film-shaped microplastics and phthalate esters were detected in the soils from the plateau. Copper, lead, cadmium and di-n-octyl phthalate detected significantly affected nitrogen cycling-related functional microorganisms. The co-existence of di-n-octyl phthalate and copper in soils synergistically stimulated the expression of denitrification microorganisms nirS gene and "nitrate_reduction". Additionally, di-n-octyl phthalate and dimethyl phthalate more significantly affected the variation of nitrogen cycling-related functional genes than the number of microplastics. In a dimethyl phthalate- and cadmium-polluted area, nitrogen cycling-related functional genes, especially nirK gene, were more sensitive and stressed. Overall, phthalate esters originated from microplastics play a key role in nitrogen cycling-related functions than microplastics themselves, moreover, the synergy between di-n-octyl phthalate and copper strengthen the expression of denitrification functions.


Subject(s)
Denitrification , Microplastics , Soil Microbiology , Soil Pollutants , Denitrification/drug effects , Soil Pollutants/toxicity , Soil Pollutants/metabolism , Tibet , Microplastics/toxicity , Plasticizers/toxicity , Plasticizers/metabolism , Microbiota/drug effects , Phthalic Acids/toxicity , Phthalic Acids/metabolism , Geologic Sediments/microbiology , Geologic Sediments/chemistry , Metals, Heavy/toxicity
14.
J Agric Food Chem ; 72(21): 12045-12056, 2024 May 29.
Article in English | MEDLINE | ID: mdl-38753963

ABSTRACT

The gene-encoding carboxylesterase (TM1022) from the hyperthermophilic bacterium Thermotoga maritima (T. maritima) was cloned and expressed in Escherichia coli Top10 and BL21 (DE3). Recombinant TM1022 showed the best activity at pH 8.0 and 85 °C and retained 57% activity after 8 h cultivation at 90 °C. TM1022 exhibited good stability at pH 6.0-9.0, maintaining 53% activity after incubation at pH 10.0 and 37 °C for 6 h. The esterase TM1022 exhibited the optimum thermo-alkali stability and kcat/Km (598.57 ± 19.97 s-1mM-1) for pN-C4. TM1022 hydrolyzed poly(ethylene terephthalate) (PET) degradation intermediates, such as bis(2-hydroxyethyl) terephthalate (BHET) and mono(2-hydroxyethyl) terephthalate (MHET). The Km, kcat, and kcat/Km values for BHET were 0.82 ± 0.01 mM, 2.20 ± 0.02 s-1, and 2.67 ± 0.02 mM-1 s-1, respectively; those for MHET were 2.43 ± 0.07 mM, 0.04 ± 0.001 s-1, and 0.02 ± 0.001 mM-1 s-1, respectively. When purified TM1022 was added to the cutinase BhrPETase, hydrolysis of PET from drinking water bottle tops produced pure terephthalic acids (TPA) with 166% higher yield than those obtained after 72 h of incubation with BhrPETase alone as control. The above findings demonstrate that the esterase TM1022 from T. maritima has substantial potential for depolymerizing PET into monomers for reuse.


Subject(s)
Bacterial Proteins , Enzyme Stability , Phthalic Acids , Thermotoga maritima , Thermotoga maritima/enzymology , Thermotoga maritima/genetics , Hydrolysis , Hydrogen-Ion Concentration , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Bacterial Proteins/chemistry , Kinetics , Phthalic Acids/metabolism , Phthalic Acids/chemistry , Substrate Specificity , Esterases/metabolism , Esterases/genetics , Esterases/chemistry , Polyethylene Terephthalates/metabolism , Polyethylene Terephthalates/chemistry , Temperature
15.
Int J Mol Sci ; 25(10)2024 May 16.
Article in English | MEDLINE | ID: mdl-38791471

ABSTRACT

Given the widespread use of esters and polyesters in products like cosmetics, fishing nets, lubricants and adhesives, whose specific application(s) may cause their dispersion in open environments, there is a critical need for stringent eco-design criteria based on biodegradability and ecotoxicity evidence. Our approach integrates experimental and computational methods based on short oligomers, offering a screening tool for the rapid identification of sustainable monomers and oligomers, with a special focus on bio-based alternates. We provide insights into the relationships between the chemical structure and properties of bio-based oligomers in terms of biodegradability in marine environments and toxicity in benchmark organisms. The experimental results reveal that the considered aromatic monomers (terephthalic acid and 2,5-furandicarboxylic acid) accumulate under the tested conditions (OECD 306), although some slight biodegradation is observable when the inoculum derives from sites affected by industrial and urban pollution, which suggests that ecosystems adapt to non-natural chemical pollutants. While clean seas are more susceptible to toxic chemical buildup, biotic catalytic activities offer promise for plastic pollution mitigation. Without prejudice to the fact that biodegradability inherently signifies a desirable trait in plastic products, nor that it automatically grants them a sustainable "license", this study is intended to facilitate the rational design of new polymers and materials on the basis of specific uses and applications.


Subject(s)
Biodegradation, Environmental , Polyesters/chemistry , Aquatic Organisms , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/toxicity , Phthalic Acids/chemistry , Phthalic Acids/toxicity , Phthalic Acids/metabolism
16.
Environ Sci Technol ; 58(19): 8182-8193, 2024 May 14.
Article in English | MEDLINE | ID: mdl-38691136

ABSTRACT

As an alternative plasticizer to conventional phthalates, di(2-ethylhexyl) terephthalate (DEHTP) has attracted considerable concerns, given its widespread detection in the environment and humans. However, the potential toxicity, especially liver toxicity, posed by DEHTP remains unclear. In this study, based on the 2017-2018 National Health and Nutrition Examination Survey, two metabolites of DEHTP, i.e., mono(2-ethyl-5-hydroxyhexyl) terephthalate (MEHHTP) and mono(2-ethyl-5-carboxypentyl) terephthalate (MECPTP), were found to be present in the urine samples of nearly all representative U.S. adults. Moreover, a positive linear correlation was observed between the concentrations of the two metabolites and the risk of nonalcoholic fatty liver disease (NAFLD) in the population. Results of weighted quantile sum and Bayesian kernel machine regression indicated that MEHHTP contributed a greater weight to the risk of NAFLD in comparison with 12 conventional phthalate metabolites. In vitro experiments with hepatocyte HepG2 revealed that MEHHTP exposure could increase lipogenic gene programs, thereby promoting a dose-dependent hepatic lipid accumulation. Activation of liver X receptor α may be an important regulator of MEHHTP-induced hepatic lipid disorders. These findings provide new insights into the liver lipid metabolism toxicity potential of DEHTP exposure in the population.


Subject(s)
Non-alcoholic Fatty Liver Disease , Phthalic Acids , Non-alcoholic Fatty Liver Disease/epidemiology , Non-alcoholic Fatty Liver Disease/metabolism , Humans , Phthalic Acids/toxicity , Phthalic Acids/metabolism , Male , Adult , Female
17.
J Assist Reprod Genet ; 41(6): 1637-1642, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38557803

ABSTRACT

PURPOSE: To determine correlations between chemicals in follicular fluid (FF) and follicular reproductive hormone levels. METHODS: The analysis was part of a larger cohort study to determine associations between exposure to EDCs and in vitro fertilization (IVF) outcomes. FF was aspirated from a single leading follicle per participant. Demographics and data on exposure to EDCs were self-reported by the participants using a questionnaire. The concentrations of estradiol (E2), progesterone (PG), anti-Mullerian hormone (AMH), and inhibin B, as well as that of 12 phthalate metabolites and 12 phenolic chemicals were measured in each FF sample. Multivariate linear regression model was used to identify the drivers of hormone levels based on participant's age, BMI, smoking status, and chemical exposure for the monitored chemicals detected in more than 50% of the samples. Benjamini-Hochberg false discovery rate (FDR) correction was applied on the resulting p values (q value). RESULTS: FF samples were obtained from 72 women (mean age 30.9 years). Most of the phthalates and phenolic substances monitored (21/24, 88%) were identified in FF. Ten compounds (7 phthalate metabolites, 3 phenols) were found in more than 50% of samples. In addition, there were positive associations between E2 levels and mono-n-butyl phthalate (MnBP) (beta = 0.01) and mono-isobutyl phthalate (MiBP) (beta = 0.03) levels (q value < 0.05). CONCLUSION: Higher concentrations of several phthalate metabolites, present among others in personal care products, were associated with increased E2 levels in FF. The results emphasize the need to further investigate the mechanisms of action of such EDCs on hormonal cyclicity and fertility in women.


Subject(s)
Anti-Mullerian Hormone , Endocrine Disruptors , Estradiol , Fertilization in Vitro , Follicular Fluid , Phthalic Acids , Progesterone , Humans , Follicular Fluid/metabolism , Follicular Fluid/chemistry , Female , Adult , Endocrine Disruptors/analysis , Phthalic Acids/metabolism , Phthalic Acids/analysis , Estradiol/analysis , Estradiol/metabolism , Progesterone/analysis , Progesterone/metabolism , Anti-Mullerian Hormone/metabolism , Inhibins/metabolism , Phenols/analysis
18.
J Hazard Mater ; 470: 134167, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38598880

ABSTRACT

This study investigated the leaching of phthalate and non-phthalate plasticizers from polyvinyl chloride microplastics (MPs) into sediment and their degradation over a 30-d period via abiotic and biotic processes. The results showed that 3579% of plasticizers were released into the sediment from the MPs and > 99.9% degradation was achieved. Although a significantly higher degradation was found in plasticizer-added microcosms under biotic processes (overall, 94%), there was a noticeable abiotic loss (72%), suggesting that abiotic processes also play a role in plasticizer degradation. Interestingly, when compared with the initial sediment-water partitioning for plasticizers, the partition constants for low-molecular-weight compounds decreased in both microcosms, whereas those for high-molecular-weight compounds increased after abiotic degradation. Furthermore, changes in the bacterial community, abundance of plasticizer-degrading bacterial populations, and functional gene profiles were assessed. In all the microcosms, a decrease in bacterial community diversity and a notable shift in bacterial composition were observed. The enriched potential plasticizer-degrading bacteria were Arthrobacter, Bacillus, Desulfovibrio, Desulfuromonas, Devosia, Gordonia, Mycobacterium, and Sphingomonas, among which Bacillus was recognized as the key plasticizer degrader. Overall, these findings shed light on the factors affecting plasticizer degradation, the microbial communities potentially involved in biodegradation, and the fate of plasticizers in the environment.


Subject(s)
Bacteria , Geologic Sediments , Microplastics , Phthalic Acids , Plasticizers , Polyvinyl Chloride , Water Pollutants, Chemical , Polyvinyl Chloride/chemistry , Plasticizers/metabolism , Geologic Sediments/microbiology , Geologic Sediments/chemistry , Phthalic Acids/metabolism , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/metabolism , Bacteria/metabolism , Bacteria/classification , Biodegradation, Environmental
19.
J Hazard Mater ; 470: 134187, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38574659

ABSTRACT

The increasing use of phthalate acid esters (PAEs) in various applications has inevitably led to their widespread presence in the aquatic environment. This presents a considerable threat to plants. However, the interactions between PAEs and plants in the aquatic environment have not yet been comprehensively reviewed. In this review, the properties, occurrence, uptake, transformation, and toxic effects of PAEs on plants in the aquatic environment are summarized. PAEs have been prevalently detected in the aquatic environment, including surface water, groundwater, seawater, and sediment, with concentrations ranging from the ng/L or ng/kg to the mg/L or mg/kg range. PAEs in the aquatic environment can be uptake, translocated, and metabolized by plants. Exposure to PAEs induces multiple adverse effects in aquatic plants, including growth perturbation, structural damage, disruption of photosynthesis, oxidative damage, and potential genotoxicity. High-throughput omics techniques further reveal the underlying toxicity molecular mechanisms of how PAEs disrupt plants on the transcription, protein, and metabolism levels. Finally, this review proposes that future studies should evaluate the interactions between plants and PAEs with a focus on long-term exposure to environmental PAE concentrations, the effects of PAE alternatives, and human health risks via the intake of plant-based foods.


Subject(s)
Esters , Phthalic Acids , Plants , Water Pollutants, Chemical , Phthalic Acids/toxicity , Phthalic Acids/metabolism , Esters/toxicity , Plants/drug effects , Plants/metabolism , Water Pollutants, Chemical/toxicity
20.
Environ Sci Technol ; 58(18): 7791-7801, 2024 May 07.
Article in English | MEDLINE | ID: mdl-38653734

ABSTRACT

Microplastics (MPs) pose potential health risks to the intestinal tract and gut microbiota, a topic that has garnered significant attention. However, the absence of quantitative assessment methods for human gut MP exposure impedes related health risk assessments. Here, we performed long-term continuous exposure experiments on mice using MPs that mimic actual human exposure characteristics. The daily excretion of fecal MPs and the concentrations of phthalates (PAEs) and their metabolites (mPAEs) in serum and urine were detected. The cumulative excretion rate of fecal MPs remains stable at about 93%. A significant linear correlation was observed between MP exposure and concentration of mPAEs in urine for both low MP (LMP; 150 µg of MPs/d) (R2 = 0.90) and high MP (HMP; 360 µg of MPs/d) groups (R2 = 0.97). Moreover, a strong correlation was found between daily PAEs exposure and total MP-associated PAEs exposure in both LMP (R2 = 0.77) and HMP (R2 = 0.88) groups. Based on these findings, we established a noninvasive model and evaluated multiple MP exposure parameters in the human gut across 6 continents, 30 countries, and 133 individuals. This study offers novel insights for the quantitative assessment of in vivo MP exposure and provides technical support for assessing the health risks of MPs.


Subject(s)
Microplastics , Mice , Animals , Humans , Feces/chemistry , Phthalic Acids/urine , Phthalic Acids/metabolism , Environmental Exposure
SELECTION OF CITATIONS
SEARCH DETAIL
...