Uptake, biotransformation and physiological response of TBBPA derivatives in Helianthus annus.

Tetrabromobisphenol A (TBBPA) and its derivatives are widely used as brominated flame retardants. Because of their high production and wide environment distribution, TBBPA derivatives have increased considerable concern. Previous studies have primarily focused on TBBPA, with limited information available on its derivative. In this study, we investigated the uptake, biotransformation and physiological response of two derivatives, Tetrabromobisphenol A bis(allyl ether) (TBBPA BAE) and Tetrabromobisphenol A bis(2,3-dibromopropylether) (TBBPA BDBPE), in Helianthus annus (H. annus) through a short-term hydroponic assay. The results revealed that H. annus could absorb TBBPA BAE and TBBPA BDBPE from solution, with removal efficiencies of 98.33 ± 0.5% and 98.49 ± 1.56% after 10 days, respectively, which followed first-order kinetics. TBBPA BAE was absorbed, translocated and accumulated while TBBPA BDBPE couldn't be translocated upward due to its high hydrophobicity and low solubility. The concentrations of TBBPA derivatives in plants peaked within 72 h, and then decreased. We identified twelve metabolites resulting from ether bond breakage, debromination, and hydroxylation in H. annus. The high-level TBBPA BAE suppressed the growth and increased malondialdehyde (MDA) content of H. annus, while TBBPA BDBPE didn't pose a negative effect on H. annus. TBBPA BAE and TBBPA BDBPE increased the activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), with higher levels of these enzymes activity found in high concentration treatments. Contrastingly, TBBPA BAE exhibited higher toxicity than TBBPA BDBPE, as indicated by greater antioxidant enzyme activity. The findings of this study develop better understanding of biotransformation mechanisms of TBBPA derivatives in plants, contributing to the assessment of the environmental and human health impacts of these contaminants.

Mechanism of tartaric acid mediated dissipation and biotransformation of tetrabromobisphenol A and its derivatives in soil.

Biotransformation is a major dissipation process of tetrabromobisphenol A and its derivatives (TBBPAs) in soil. The biotransformation and ultimate environmental fate of TBBPAs have been widely studied, yet the effect of root exudates (especially low-molecular weight organic acids (LMWOAs)) on the fate of TBBPAs is poorly documented. Herein, the biotransformation behavior and mechanism of TBBPAs in bacteriome driven by LMWOAs were comprehensively investigated. Tartaric acid (TTA) was found to be the main component of LMWOAs in root exudates of Helianthus annus in the presence of TBBPAs, and was identified to play a key role in driving shaping bacteriome. TTA promoted shift of the dominant genus in soil bacteriome from Saccharibacteria_genera_incertae_sedis to Gemmatimonas, with a noteworthy increase of 24.90-34.65% in relative abundance of Gemmatimonas. A total of 28 conversion products were successfully identified, and ß-scission was the principal biotransformation pathway for TBBPAs. TTA facilitated the emergence of novel conversion products, including 2,4-dibromophenol, 3,5-dibromo-4-hydroxyacetophenone, para-hydroxyacetophenone, and tribromobisphenol A. These products were formed via oxidative skeletal cleavage and debromination pathways. Additionally, bisphenol A was observed during the conversion of derivatives. This study provides a comprehensive understanding about biotransformation of TBBPAs driven by TTA in soil bacteriome, offering new insights into LMWOAs-driven biotransformation mechanisms.

The dissipation of organophosphate esters mediated by ryegrass root exudate oxalic acid in soil: Analysis of enzymes activities, microorganism.

Complex rhizoremediation is the main mechanism of phytoremediation in organic-contaminated soil. Low molecular weight organic acids (LMWOAs) in root exudates have been shown to increase the bioavailability of contaminants and are essential for promoting the dissipation of contaminants. The effects of root exudates on the dissipation of organophosphate esters (OPEs) in soil are unclear. Consequently, we studied the combined effects of root exudates, soil enzymes and microorganisms on OPEs (tri (1-chloro-2-propyl) phosphate (TCPP) and triphenyl phosphate (TPP)) dissipation through pot experiments. Oxalic acid (OA) was confirmed to be the main component of LMWOAs in root exudates of ryegrass. The existence of OA increased the dissipation rate of OPEs by 6.04%-25.50%. Catalase and dehydrogenase activities were firstly activated and then inhibited in soil. While, urease activity was activated and alkaline phosphatase activity was inhibited during the exposure period. More bacteria enrichment (e.g., Sphingomonas, Pseudomonas, Flavisolibacter, Pontibacter, Methylophilus and Massilia) improved the biodegradation of OPEs. In addition, the transformation paths of OPEs hydrolysis and methylation under the action of root exudates were observed. This study provided theoretical insights into reducing the pollution risk of OPEs in the soil.

The bioaccumulation and biotransformation of tetrabromobisphenol A bis (allyl ether) in common carp (Cyprinus carpio).

Tetrabromobisphenol A bis (allyl ether) (TBBPA-BAE) is an extensively used brominated flame retardant, which has raised considerable concern because of its neurotoxic and endocrine disruption effects on aquatic organisms. However, previous studies mainly focused on the parent compound before modification, tetrabromobisphenol A (TBBPA), and little information is available about the bioconcentration and biotransformation of TBBPA derivatives in fish. In this study, we investigated the tissue-specific uptake, elimination kinetic, and biotransformation of TBBPA-BAE in common carp (Cyprinus carpio). The fish were exposed to TBBPA-BAE at environmentally relevant concentrations (20 µg·L-1) for 28 days, followed by 14 days of depuration. The results showed TBBPA-BAE could rapidly accumulate in common carp. Among the seven tissues studied, the highest concentrations of TBBPA-BAE were observed in the liver (6.00 µg·g-1 wet weight [ww]) on day 24, while the longest residence time was observed in the kidney (t1/2 values of 18.7 days). Biotransformation of TBBPA-BAE was documented in the in vivo experiments, and 14 different phase I and phase II metabolites were identified in the liver. These findings suggest the biotransformation products of TBBPA-BAE should be considered for a comprehensive risk evaluation.

Phenolic hydroxyl derived copper alginate microspheres as superior adsorbent for effective adsorption of tetracycline.

Significant concerns had been given raise to the pollution of tetracycline in aquatic environment in recent years. In this study, a novel phenolic hydroxyl (bayberry tannin) functionalized copper alginate microspheres adsorbent for the adsorption of tetracycline from contaminated water environment had been synthesized by a facile gelation and solidification process. The structure and chemical properties were characterized by the various analytical methods. The as-prepared adsorbent displayed the excellent adsorption performance with the maximum adsorption capacity of 153.89 mg·g-1, and the equilibrium data were well fitted the Langmuir isotherm model and pseudo-second-order kinetic model. In addition, the thermodynamic values (ΔH0 > 0, ΔS0 > 0, ΔG0 < 0) demonstrated that the tetracycline adsorption process was feasible, endothermic and spontaneous in nature. The possible preparation and adsorption mechanisms of as-prepared adsorbent were the result of hydrogen bond, cation bonding bridge, n-π EDA interaction, hydrophobic interaction and π-π EDA interaction. Compared with other adsorbents, the as-prepared adsorbent could be considered a high performance and promising candidate for the effective removal of tetracycline from aquatic environment.

Novel alginate particles decorated with nickel for enhancing ciprofloxacin removal: Characterization and mechanism analysis.

The extensive occurrence of antibiotics (such as ciprofloxacin) in aqueous environment had raised severe concerns due to their impacts on humans and the ecosystem. In this study, a novel nickel alginate particles adsorbent had been successfully developed by combining an alginate matrix with nickel ion through immobilization and crosslinking technology and then was applied for the batch adsorption study of ciprofloxacin to evaluate its potential performance. The as-prepared adsorbent exhibited excellent adsorption performance at the condition of the pH 7 and 328.15 K, and the results indicated that the maximum adsorption capacity was 135.18 mg g-1. The isotherm and kinetic studies were well fitted to the Langmuir and pseudo-second-order models, respectively. A thermodynamics analysis displayed that the ciprofloxacin adsorption process was endothermic, feasible and spontaneous. The as-prepared adsorbent before and after adsorption was characterized through SEM, EDX and XPS analyses, and the particle size of the as-prepared adsorbent was roughly 914 µm. Hydrogen bond, the cation bonding bridge and n-π electron-donor-acceptor interaction might be the driving force of the ciprofloxacin adsorption process. This study demonstrated that this as-prepared adsorbent was a promising and efficient material for the ciprofloxacin adsorption from the aqueous solution.

Study on adsorption of tetracycline by Cu-immobilized alginate adsorbent from water environment.

Widespread concern had been given raise to the pollution of antibiotics including tetracyclines in water environment in recent years. A novel Cu-immobilized alginate adsorbent had been synthesized successfully through a facile fabrication way called sol-gel method, and its adsorption performance had been investigated for the tetracycline removal at various conditions, including the pH, temperature, the dosage of adsorbent, concentration and contact time. The adsorbent was characterized with SEM, EDX, FT-IR and XPS analyses to confirm its properties before and after adsorption. The equilibrium data was fitted well with the Freundlich isotherm model and the maximum adsorption capacity for tetracycline was 53.26 mg·g-1 at pH 3, 318.15 K, and 90 mg·L-1 tetracycline solution. The pseudo-second-order kinetic and Freundlich isotherm models combining with the correlative analysis implied that the tetracycline adsorption onto the Cu-immobilized alginate adsorbent was administrated by the n-π electron-donor-acceptor interaction (n-π EDA interaction), hydrogen bond and the cation bonding bridge. Moreover, thermodynamic study demonstrated that the nature of tetracycline adsorption was endothermic, feasible and spontaneous. Compared with the other adsorbents, the as-prepared adsorbent had an excellent tetracycline adsorption capacity, and was expected to be widely applied in the adsorption treatment of tetracycline wastewater.

Adsorption of phosphorus from slaughterhouse wastewater by carboxymethyl konjac glucomannan loaded with lanthanum.

Phosphorus removal was an important measure in the control of eutrophication of water environment. In this study, a novel phosphorus removal adsorbent of lanthanum-loaded carboxymethyl konjac glucomannan microspheres (CMKGM-La) was successfully prepared by the method of electrostatic spraying and sol-gel, and was characterized by SEM, XPS and EDX. Batch experiments were performed to evaluate the adsorption capacity at different conditions: pH, temperature, initial concentration, adsorbent dosage and contact time. The results showed that the adsorption kinetics data correlated well with the pseudo-second-order kinetic model and the adsorption isotherm was well described by the Langmuir isotherm model with the maximum capacity of 16.06 mg·g-1 for CMKGM-La microspheres at pH of 4 and 318.15 K. The adsorption of phosphorus was a spontaneous, entropy-increasing and endothermic process. The possible adsorption mechanism of phosphorus on the CMKGM-La microspheres consisted of the coordination reaction of La (III) with phosphorus and electrostatic attraction between protonated hydroxyl and phosphorus. The presence of co-existing ions (such as NH4+, Cl-, SO42-, SiO32- and CO32-) had no significant effect on phosphorus removal. These results suggested that the adsorbent of CMKGM-La microspheres was a promising adsorbent for the removal of phosphorus from slaughterhouse wastewater.

Catalytic synthesis of sulfated polysaccharides I: Characterization of chemical structure.

In the present study, sulfated derivatives of Artemisia sphaerocephala polysaccharide (SASP) with high degree of substitution (DS) were synthesized by using 4-dimethylaminopyridine (DMAP)/dimethylcyclohexylcarbodiimide (DCC) as catalyst in homogeneous conditions. It was found that DMAP/DCC showed marked improvement in DS of sulfated samples. Compared to sulfated derivatives without catalyst, the DS of SASP increased from 0.91 to 1.28 with an increment in dosage of DMAP from 0 to 10 mg. The influence of DMAP/DCC on the DS of sulfated derivatives was depended on the content of DMAP. The effect of DMAP might be due to its strong coordination to the hydroxy group. The results of FT-IR and X-ray photoelectron spectroscopy (XPS) indicated that SO3- group (S6+, binding energy of 172.3 eV) was widely present in sulfated polysaccharide molecules. 13C NMR results indicated that C-6 substitution was predominant for sulfated polysaccharide when compared with other positions. In the sulfation reaction, a sharp decrease in MW was observed. DMAP/DCC was an effective catalyst system in sulfated modification of polysaccharide.

Combination of pharmacophore hypothesis, genetic function approximation model, and molecular docking to identify novel inhibitors of S6K1.

S6K1 has emerged as a potential target for the treatment for obesity, type II diabetes and cancer diseases. Discovery of S6K1 inhibitors has thus attracted much attention in recent years. In this investigation, a hybrid virtual screening method that involves pharmacophore hypothesis, genetic function approximation (GFA) model, and molecular docking technology has been used to discover S6K1 inhibitors especially with novel scaffolds. The common feature pharmacophore hypothesis and GFA regression model of S6K1 inhibitors were first developed and applied in a virtual screen of the Specs database for retrieving S6K1 inhibitors. Then, the molecular docking method was carried out to re-filter these screened compounds. Finally, 60 compounds with promising S6K1 inhibitory activity were carefully selected and have been handed over to the other group to complete the follow-up compound synthesis (or purchase) and activity test.