Leaching of triphenyl phosphate and tri-n-butyl phosphate from polystyrene microplastics: influence of plastic properties and simulated digestive fluids.

Microplastics have gained considerable attention as a growing environmental problem owing to their potential to serve as vectors for harmful chemicals. However, the leaching of these chemicals from microplastics is unclear. In this study, we investigated the leaching of two organophosphate flame retardants, triphenyl phosphate and tri-n-butyl phosphate, from polystyrene microplastics in simulated digestive fluids and water, and polypropylene microplastics were simultaneously used for comparison with polystyrene microplastics. The results indicated that the first-order kinetic model best explained the leaching process, suggesting that leaching was related to the release of organophosphate flame retardant molecules at the polymer surface. Additionally, the size and crystalline state of the microplastics had a significant effect on the leaching, whereas organophosphate flame retardant content had a minimal impact. Simulated digestive fluids facilitated the leaching to a different extent, and under these influencing conditions, leaching percentages from polystyrene microplastics did not exceed 0.51%. Therefore, leaching from PS microplastics may not be an important source of OPFRs in the environment. However, the release of organophosphate flame retardants can be considerably enhanced with the breakdown of polystyrene microplastics to polystyrene nanoplastics.

Acute stress of the typical disinfectant glutaraldehyde-didecyldimethylammonium bromide (GD) on sludge microecology in livestock wastewater treatment plants: Effect and its mechanisms.

Glutaraldehyde and didecyldimethylammonium bromide (GD) is a disinfectant widely used to prevent African swine fever (ASF) in livestock farms. However, the effect of residual GD on the activated sludge microbial ecology of receiving wastewater treatment plants (WWTPs) remains largely unknown. In this study, seven simulated systems were established to research the effects of GD on WWTPs and reveal the underlying mechanisms of microecological responses to GD at different concentrations. Both the nitrogen and carbon removal rates decreased with increasing GD concentrations, and nitrogen metabolism was inhibited more obviously, but the inhibition weakened with increasing stress duration. Microorganisms activated their SoxRS systems to promote ATP synthesis and electron transfer to support the hydrolysis and efflux of GD by producing a small number of ROS when exposed to GD at less than 1 mg/L. The overproduction of ROS led to a decrease of antioxidant and nitrogen removal enzyme activities, and upregulation of the porin gene increased the risk of GD entering the intracellular space upon exposure to GD at concentrations higher than 1 mg/L. Some denitrifiers survived via resistance and their basic capabilities of sugar metabolism and nitrogen assimilation. Notably, low concentrations of disinfectants could promote vertical and horizontal transfer of multiple resistance genes, especially aminoglycosides, among microorganisms, which might increase not only the adaptation capability of denitrifiers but also the risk to ecological systems. Therefore, the risks of disinfectants targeting ASF on ecology and health as well as the effects of disinfectant residuals from the COVID-19 epidemic should receive more attention.

Liquid chromatography-tandem mass spectrometry analysis for identification and quantification of antimicrobial compounds in distillery wastewater.

A high-resolution mass spectrometry (HR-MS) method was developed to analyze and identify small molecule compounds in distillery wastewater. According to identification confidence levels, 4 levels of compounds were identified. The five antimicrobial compounds (lactic acid, succinic acid, acetophenone, cinnamic acid, and phenyllactic acid), which shown in high concentrations, were at the highest level of confidence (level 1, confirmed structure). Thus, a rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to simultaneously quantify these antimicrobial compounds. The analysis was performed in the selective reaction monitoring (SRM) mode via the electrospray ionization (ESI) source operating in the negative ionization mode. Linear calibration curves were obtained over the concentration range of 50-1000.0 ng/mL for succinic acid, acetophenone, cinnamic acid, phenyllactic acid, and 375-7500 ng/mL for lactic acid. Precision and recovery of the analytes were all satisfactory (relative standard deviation < 10%). The validated method was successfully applied to quantitative analysis of the five antimicrobial compounds in distillery wastewater.•Analyze and identify 4 levels of small molecule compounds in distillery wastewater.•Simple method for quantification of five antimicrobial compounds.•Column temperature affected the lactic and succinic acid chromatographs significantly.

Microbial contamination control mechanism in lipid production using distillery wastewater and oleaginous yeast - Antimicrobial compounds in wastewater as a double-edged sword.

Microbial contamination and the high expense of sterilization are the key factors limiting the application of resource recovery in processes such as producing lipids (can be converted to biodiesel via transesterification) from wastewater. This study was conducted to study the succession of contaminating and indigenous microorganisms, analyze the mechanism and propose a control strategy for undesirable microorganisms in the non-sterile lipid production process using distillery wastewater and oleaginous yeast. In the early stage, indigenous microorganisms (Pichia, Saccharomyces, Acetobacter and Gluconobacter) were the main competitors. Based on antimicrobial experiment and analyses of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography mass spectrometry (GC-MS), the antimicrobial compounds (such as lactic acid 10,011-17,498 mg/L, succinic acid 210-325 mg/L and furfural 0.63-1.23 mg/L) combined with the low pH (3.2-3.8) in distillery wastewater played the primary role in the prevention of contaminating bacteria in this stage rather than the potential antimicrobial compounds from oleaginous yeast. Cinnamic acid (56-143 mg/L) was the main inhibitor against oleaginous yeast among the major antimicrobial compounds in wastewater. Its inhibition decreased when pH increased from 3.2 to 5.5. In the later stage, as the pH increased to over 7 during the culture, heterotrophic bacteria (Chryseobacterium and Sphingobacterium) with a relatively low tolerance for acidic conditions became the dominant undesirable microorganisms. Utilizing the antimicrobial activity of distillery wastewater combined with a high inoculum size and proper pH control could be effective for achieving dominant oleaginous yeast growth and improving lipid production in non-sterile conditions.

Anodic oxidation of ciprofloxacin using different graphite felt anodes: Kinetics and degradation pathways.

Ciprofloxacin (CIP) is ubiquitous in the environment which poses a certain threat to human and ecology. In this investigation, the physical and electrochemical properties of graphite felt (GF) anodes which affected the anodic oxidation (AO) performance, and the CIP removal effect of GF were evaluated. The GFs were used as anodes for detection of ·OH with coumarin (COU) as molecule probe and removal of CIP in a 150 mL electrolytic cell with Pt cathode (AO-GF/Pt system). The results showed that hydrophilic GF (B-GF) owned higher sp3/sp2 and more oxygen-containing and nitrogen-containing functional groups than the hydrophobic GF (A-GF). Moreover, B-GF possessed higher oxygen evolution potential (1.12 V), more active sites and stronger ·OH generation capacity. Above mentioned caused that B-GF exhibited more superior properties for CIP removal. The best efficiencies (96.95%, 99.83%) were obtained in the AO-B-GF/Pt system at 6.25 mAcm-2 after 10 min (k1, 0.356 min-1) and 60 min (k2, 0.224 min-1), respectively. Furthermore, nine degradation pathways of CIP in AO-B-GF/Pt system were summarized as the cleavage of the piperazine ring, cyclopropyl group, quinolone ring and F atom by ·OH. It provides new insights into the removal and degradation pathways of CIP with GF in AO system.

Targeted metabolomics analysis of aromatic amino acids and their gut microbiota-host cometabolites in rat serum and urine by liquid chromatography coupled with tandem mass spectrometry.

Gut microbiota-host cometabolites are closely related to various diseases. Monitoring dynamic changes of cometabolites can provide a more comprehensive understanding of pathophysiology. Here, a novel liquid chromatography-tandem mass spectrometry method was performed for the analysis of aromatic amino acids and their gut microbiota-host cometabolites in rat serum and urine. In the developed method, seven key gut microbiota-host cometabolites were chromatographically separated on a Kinetex Phenyl-Hexyl column by gradient elution, and the run time was 6 min. Serum and urine were extracted by protein precipitation. This method was linear between 10.20 and 1000.00 ng/mL for phenylalanine and p-cresyl sulfate; 25.60-2500.00 ng/mL for tryptophan; 51.20-5000.00 ng/mL for tyrosine, indole, and indoxyl sulfate; and 75.50-7500.00 ng/mL for p-cresol. The linearity, accuracy, precision, and recovery of seven analytes were all satisfactory. The method was sufficiently sensitive and robust. It was successfully applied to characterize the alterations of gut microbiota-host cometabolites in inflammatory disorders. All of these results suggest that the developed method is able to simultaneously monitor aromatic amino acids and their gut microbiota-host cometabolites. This method will be expected to be a valuable tool for clinical researches and comprehensive studies of the pathophysiological roles.

Target-based metabolomics for the quantitative measurement of 37 pathway metabolites in rat brain and serum using hydrophilic interaction ultra-high-performance liquid chromatography-tandem mass spectrometry.

Amino acids, neurotransmitters, purines, and pyrimidines are bioactive molecules that play fundamental roles in maintaining various physiological functions. Their metabolism is closely related to the health, growth, development, reproduction, and homeostasis of organisms. Most recently, comprehensive measurements of these metabolites have shown their potential as innovative approaches in disease surveillance or drug intervention. However, simultaneous measurement of these metabolites presents great difficulties. Here, we report a novel quantitative method that uses hydrophilic interaction ultra-high-performance liquid chromatography-tandem mass spectrometry (HILIC-UPLC-MS/MS), which is highly selective, high throughput, and exhibits better chromatographic behavior than existing methods. The developed method enabled the rapid quantification of 37 metabolites, spanning amino acids, neurotransmitters, purines, and pyrimidines pathways, within 6.5 min. The compounds were separated on an ACQUITY UPLC® BEH Amide column. Serum and brain homogenate were extracted by protein precipitation. The intra- and interday precision of all of the analytes was less than 11.34 %, and the accuracy was between -11.74 and 11.51 % for all quality control (QC) levels. The extraction recoveries of serum ranged from 84.58 % to 116.43 % and those of brain samples from 80.80 % to 119.39 %, while the RSD was 14.61 % or less for all recoveries. This method was used to successfully characterize alterations in the rat brain and, in particular, their dynamics in serum. The following study was performed to simultaneously test global changes of these metabolites in a serotonin antagonist p-chlorophenylalanine (PCPA)-induced anxiety and insomnia rat model to understand the effect and mechanism of PCPA. Taken together, these results show that the method is able to simultaneously monitor a large panel of metabolites and that this protocol may represent a metabolomic method to diagnose toxicological and pathophysiological states.

A strategy for the targeted metabolomics analysis of 11 gut microbiota-host co-metabolites in rat serum, urine and feces by ultra high performance liquid chromatography-tandem mass spectrometry.

Microbiota-host co-metabolites are well-known to play important physiological roles, and their dysregulation has been found to be closely related to various diseases, including but not limited to inflammatory disorders. We developed herein an original and feasible method using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The method developed enables rapid quantification of 11 key gut microbiota-host co-metabolites spanning the succinate, phenylacetylglutamine, hippurate and trimethylamine metabolic pathways within 10 min. With this method, we were able to simultaneously monitor inflammation-induced alterations of these metabolites in rat serum, urine and feces matrices. The measured levels for this panel of endogenous metabolites ranged from 0.001 to 172.8 µg m L(-1). The intra- and inter-day precision of three analytes was less than 13.1% and the accuracy was between -13.0 to 11.2% for all QC levels. The extraction recoveries in serum ranged from 85.4 to 103.2%, while the RSD was 9.0% or less for all recoveries. In addition, extraction recoveries of 11 analytes in urine and feces samples were between 85.7% and 102.0% and RSD was less than 9.5%. The method developed here has been successfully applied to the analysis of real samples from 2,4,6-trinitrobenzenesulfonic acid-induced Crohn's disease in rats. All of these results suggest that the presently developed method is sufficiently sensitive and robust to simultaneously monitor co-metabolites with diverse properties and a range of different concentrations. Therefore, this method will be expected to be useful for comprehensive studies of the pathophysiological roles and mechanisms of these key microbiota-host co-metabolites, which reflect the function of the intestine, consequently offering novel opportunities for evaluating the occurrence, development and therapeutic effects of diseases related to microbiota disturbances.

Integrated pharmacokinetics of five protoberberine-type alkaloids in normal and insomnic rats after single and multiple oral administration of Jiao-Tai-Wan.

ETHNOPHARMACOLOGICAL RELEVANCE: Jiao-Tai-Wan (JTW), an important herbal formula consists of Rhizoma coptidis and Cortex cinnamomi powder, is a famous prescription which has been used for centuries to treat insomnia in Traditional Chinese Medicine. The purpose of this study is to compare the pharmacokinetic properties of five protoberberine-type alkaloids (i.e. berberine, palmatine, coptisine, epiberberine and jatrorrhizine), the main bioactive constituents in JTW, between normal and insomnic rats. We also investigate the differences between single-dose and multiple-dose pharmacokinetics of five protoberberine-type alkaloids. MATERIALS AND METHODS: The insomnic rat models were induced by intraperitoneal injection of one-dose para-chlorophenylalanine acid (PCPA). Quantification of five protoberberine-type alkaloids in rat plasma was achieved by using a rapid LC-MS/MS method. Plasma samples were collected at different time points to construct pharmacokinetic profiles by plotting drug concentration versus time and estimate pharmacokinetic parameters. An unpaired Student׳s t test was used for comparisons with SPSS 17.0. RESULTS: The five protoberberine-type alkaloids of single-dose normal groups had slow absorption and low bioavailability, as well as a delay of peak time. In the single-dose oral administration, the Cmax and Tmax of five ingredients in insomnic rats had significant differences compared with those of normal rats. In the multiple-dose oral administration, the pharmacokinetic parameters of five protoberberine-type alkaloids varied greatly in insomnic rats. In the normal rats, there were significant differences (P<0.05) in the principal pharmacokinetic parameters such as Cmax and Tmax between single-dose and multiple-dose oral administration. In the insomnic rats, the five ingredients of multiple-dose groups showed better absorption than the single-dose groups. Particularly, three peaks were observed in multiple-dose model group of plasma-concentration curves. CONCLUSIONS: The pharmacokinetic behavior of five protoberberine-type alkaloids was described in this paper. In both normal groups and model groups, the pharmacokinetic behavior of multiple-dose had significant differences comparing with the single-dose; either single-dose or multiple-dose, the pharmacokinetic behavior of insomnic rats had significant differences comparing the normal rats. Multiple dosing may improve the absorption of JTW in insomnic rats, which will increase the bioavailability and bring into active role in therapeutical effect.