Widespread occurrence of two typical N, N'-substituted p-phenylenediamines and their quinones in humans: Association with oxidative stress and liver damage.

While N, N'-substituted p-phenylenediamines (PPDs) and their quinone derivatives (PPDQs) have been widely detected in the environment, there is currently limited data on their occurrence in humans. In this study, we conducted the first serum analysis of two PPDs and PPDQs in the healthy and secondary nonalcoholic fatty liver disease (S-NAFLD) cohorts in South China. The concentrations of four oxidative stress biomarkers (OSBs), namely, 8-iso-prostaglandin F2α (8-PGF2α), 11ß-prostaglandin F2α (11-PGF2α), 15(R)-prostaglandin F2α (15-PGF2α), and 8-hydroxy-2'-deoxyguanosine in serum samples were also measured. Results showed that N-(1,3-dimethybutyl)-N'-phenyl-p-phenylenediamine (6PPD) quinone was the predominant target analytes both in the healthy and S-NAFLD cohorts, with the median concentrations of 0.13 and 0.20 ng/mL, respectively. Significant (p < 0.05) and positive correlations were found between 6PPD concentration and 8-PGF2α, 11-PGF2α, and 15-PGF2α in both the healthy and S-NAFLD cohorts, indicating that 6PPD may be associated with lipid oxidative damage. In addition, concentrations of 6PPD in serum were associated significantly linked with total bilirubin (ß = 0.180 µmol/L, 95%CI: 0.036-0.396) and direct bilirubin (DBIL, ß = 0.321 µmol/L, 95%CI: 0.035-0.677) related to hepatotoxicity. Furthermore, 8-PGF2α, 11-PGF2α, and 15-PGF2α mediated 17.1%, 24.5%, and 16.6% of 6PPD-associated DBIL elevations, respectively. Conclusively, this study provides novel insights into human exposure to and hepatotoxicity assessment of PPDs and PPDQs.

EISA-EXPOSOME: One Highly Sensitive and Autonomous Exposomic Platform with Enhanced in-Source Fragmentation/Annotation.

Lacking a highly sensitive exposome screening technique is one of the biggest challenges in moving exposomic research forward. Enhanced in-source fragmentation/annotation (EISA) has been developed to facilitate molecular identification in untargeted metabolomics and proteomics. In this work, with a mixture of 50 pesticides at three concentration levels (20, 4, and 0.8 ppb), we investigated the analytical performance of the EISA technique over the well-accepted targeted MS/MS mode (TMM) in the detection and identification of chemicals at low levels using a quadrupole time-of-flight (qTOF) instrument. Compared with the TMM method, the EISA technique can recognize additional 1, 20, and 23 chemicals, respectively, at the three concentration levels (20, 4, and 0.8 ppb, respectively) investigated. At the 0.8 ppb level, intensities of precursor ions and fragments observed using the EISA technique are 30-1,154 and 3-80 times higher, respectively, than those observed at the TMM mode. A higher matched fragment ratio (MFR) between the EISA technique and the TMM method was recognized for most chemicals. We further developed a chemical annotation informatics algorithm, EISA-EXPOSOME, which can automatically search each precursor ion (m/z) in the MS/MS library against the EISA MS1 spectra. This algorithm then calculated a weighted score to rank the candidate features by comparing the experimental fragment spectra to those in the library. The peak intensity, zigzag index, and retention time prediction model as well as the peak correlation coefficient were further adopted in the algorithm to filter false positives. The performance of EISA-EXPOSOME was demonstrated using a pooled dust extract with a pesticide mixture (n = 200) spiked at 5 ppb. One urine sample spiked with a contaminant mixture (n = 50) at the 5 ppb level was also used for the validation of the pipeline. Proof-of-principal application of EISA-EXPOSOME in the real sample was further evaluated on the pooled dust sample with a modified T3DB database (n = 1650). Our results show that the EISA-EXPOSOME algorithm can remarkably improve the detection and annotation coverage at trace levels beyond the traditional approach as well as facilitate the high throughput screening of suspected chemicals.

Eight novel brominated flame retardants in indoor and outdoor dust samples from the E-waste recycling industrial park: Implications for human exposure.

As alternatives for legacy brominated flame retardants, novel brominated flame retardants (NBFRs) have a wide array of applications in the electronic and electrical fields. The shift of recycling modes of electronic and electrical waste (e-waste) from informal recycling family workshop to formal recycling facilities might come with the change the chemical landscape emitted including NBFRs, however, little information is known about this topic. This study investigated the occurrence characteristics, distribution, and exposure profiles of eight common NBFRs and their derivatives in an e-waste recycling industrial park in central China and illustrated the differences in various functional zones in the recycling park. The highest level of ΣNBFRs in dust samples was found in e-waste storage area at median concentration of 27,400 ng/g, followed by e-waste dismantling workshops (23,300 ng/g), workshop outdoor area (7770 ng/g), and residential area outdoor (536 ng/g). In the e-waste dismantling associated dust samples, tetrabromobisphenol A bis(2,3-dibromopropyl ether) (TBBPA-BDBPE), tetrabromobisphenol A (TBBPA) and 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ) were the predominant components. This paper presented the first evidence regarding the occurrence characteristic and distribution of tetrabromobisphenol S (TBBPS), tetrabromobisphenol A bismethyl ether (TBBPA-BME) and tetrabromobisphenol S bis(2,3-dibromopropyl ether) (TBBPS-BDBPE) in the e-waste associated dust samples. By comparing with previous studies performed in China, this paper also noticed the significant decrease of TBBPA concentrations in the dust probably due to the shift of e-wastes sources and recycling modes. We further assessed the risk of occupational workers exposure to NBFRs. The median EDI (estimated daily intake) value of ΣNBFRs among e-waste dismantling workers was 9.71 ng/kg BW/d with the maximum EDI value being 19.6 ng/kg BW/d, hundreds of times higher than those exposed by general population. The study raises great concern for the health risk of occupational exposure to NBFRs in the e-waste recycling industrial park.

eDNA-based diversity and multitrophic network reveal the effects of land use and pollutants on the subtropical Dongjiang River systems.

Biodiversity and its constituted multitrophic network in rivers are accelerating change under human land use and pollutants. However, due to the lack of complete datasets across taxa limited by traditional morphological biomonitoring, the change patterns of biodiversity and multitrophic networks are still unclear. Here, we used the eDNA approach to capture multitrophic communities (including fish, aquatic insects, protozoa, diatom and bacteria) in the Dongjiang River, a typical subtropical river in southeast China, and analyzed the changing patterns of biodiversity and multitrophic networks in relation to land use and water pollution. First, our data showed that the eDNA approach provided a snapshot of the multitrophic communities in the Dongjiang River, and the monitored 5833 OTUs were annotated to 55 phyla, 144 classes, 329 orders, 521 families, 945 genera and 406 species. Second, the multitrophic diversity index had similar patterns on the longitudinal scale of rivers, with significant decreases from the upstream to the downstream, while individual taxonomic groups exhibited variable spatial patterns. While there were similar spatial patterns between network metrics and diversity index, the former had stronger relationships with the spatial distance. Third, the multitrophic diversity and networks were significantly negatively correlated with land use and water pollution (e.g., CODMn), and network structures often had stronger and non-linear responses. Overall, this study highlights that eDNA biomonitoring of multitrophic communities and networks can provide deeper insights into ecosystem changes and help develop more targeted management strategies.

Changing on the Concentrations of Neonicotinoids in Rice and Drinking Water through Heat Treatment Process.

Neonicotinoids (NEOs) have become the most widely used insecticides in the world since the mid-1990s. According to Chinese dietary habits, rice and water are usually heated before being consumed, but the information about the alteration through the heat treatment process is very limited. In this study, NEOs in rice samples were extracted by acetonitrile (ACN) and in tap water, samples were extracted through an HLB cartridge, then, a high-performance liquid chromatography system and a triple quadrupole mass spectrometry (HPLC-MS/MS) were applied for target chemical analysis. The parents of NEOs (p-NEOs) accounted for >99% of the total NEOs mass (∑NEOs) in both uncooked (median: 66.8 ng/g) and cooked (median: 41.4 ng/g) rice samples from Guangdong Province, China, while the metabolites of NEOs (m-NEOs) involved in this study accounted for less than 1%. We aimed to reveal the concentration changes of NEOs through heat treatment process, thus, several groups of rice and water samples from Guangdong were cooked and boiled, respectively. Significant (p < 0.05) reductions in acetamiprid, imidacloprid (IMI), thiacloprid, and thiamethoxam (THM) have been observed after the heat treatment of the rice samples. In water samples, the concentrations of THM and dinotefuran decreased significantly (p < 0.05) after the heat treatment. These results indicate the degradation of p-NEOs and m-NEOs during the heat treatment process. However, the concentrations of IMI increased significantly in tap water samples (p < 0.05) after heat treatment process, which might be caused by the potential IMI precursors in those industrial pesticide products. The concentrations of NEOs in rice and water can be shifted by the heat treatment process, so this process should be considered in relevant human exposure studies.

Deciphering Gut Microbiome Responses upon Microplastic Exposure via Integrating Metagenomics and Activity-Based Metabolomics.

Perturbations of the gut microbiome are often intertwined with the onset and development of diverse metabolic diseases. It has been suggested that gut microbiome perturbation could be a potential mechanism through which environmental chemical exposure induces or exacerbates human diseases. Microplastic pollution, an emerging environmental issue, has received ever increasing attention in recent years. However, interactions between microplastic exposure and the gut microbiota remain elusive. This study aimed to decipher the responses of the gut microbiome upon microplastic polystyrene (MP) exposure by integrating 16S rRNA high-throughput sequencing with metabolomic profiling techniques using a C57BL/6 mouse model. The results indicated that MP exposure significantly perturbed aspects of the gut microbiota, including its composition, diversity, and functional pathways that are involved in xenobiotic metabolism. A distinct metabolite profile was observed in mice with MP exposure, which probably resulted from changes in gut bacterial composition. Specifically, untargeted metabolomics revealed that levels of metabolites associated with cholesterol metabolism, primary and secondary bile acid biosynthesis, and taurine and hypotaurine metabolism were changed significantly. Targeted approaches indicated significant perturbation with respect to the levels of short-chain fatty acids derived from the gut microbiota. This study can provide evidence for the missing link in understanding the mechanisms behind the toxic effects of microplastics.

Infantile Internal and External Exposure to Neonicotinoid Insecticides: A Comparison of Levels across Various Sources.

Little is known about exposure of infants to neonicotinoid insecticides (NEOs). In this study, concentrations of six parent NEOs (p-NEOs) and N-desmethyl-acetamiprid (N-dm-ACE) were measured in urine and whole blood samples from infants, in addition to breast milk, infant formula, and tap water collected in South China. The p-NEO with the highest median concentration in urine (0.25 ng/mL) and blood (1.30) samples was dinotefuran (DIN), while imidacloprid (IMI) was abundant in breast milk (median: 0.27 ng/mL), infant formula (0.22), and tap water (0.028). The older infants (181-360 days) might face higher NEO and N-dm-ACE exposure than younger infants (0-180 days). Blood samples contained a significantly (p < 0.01) higher median concentration of ∑6p-NEOs (2.03 ng/mL) than that of urine samples (0.41), similar to acetamiprid (ACE), IMI, thiacloprid (THD), DIN, and N-dm-ACE, suggesting that NEOs readily partition into blood. Furthermore, breast-fed infants tend to have higher exposure levels than formula-fed infants. Infant formula prepared with tap water augmented the daily intake of ∑NEOs. The external sources contributed 80% of the total dose to IMI and clothianidin (CLO) exposure, while other unknown sources contributed to ACE, THD, and DIN exposure in infants. To the best of our knowledge, this is the first study to assess levels and sources of infantile exposure to NEOs through internal and external exposure assessment.

Quantitative multiple fragment monitoring with enhanced in-source fragmentation/annotation mass spectrometry.

Analytical techniques with high sensitivity and selectivity are essential to the quantitative analysis of clinical samples. Liquid chromatography coupled to tandem mass spectrometry is the gold standard in clinical chemistry. However, tandem mass spectrometers come at high capital expenditure and maintenance costs. We recently showed that it is possible to generate very similar results using a much simpler single mass spectrometry detector by performing enhanced in-source fragmentation/annotation (EISA) combined with correlated ion monitoring. Here we provide a step-by-step protocol for optimizing the analytical conditions for EISA, so anyone properly trained in liquid chromatography-mass spectrometry can follow and apply this technique for any given analyte. We exemplify the approach by using 2-hydroxyglutarate (2-HG) which is a clinically relevant metabolite whose D-enantiomer is considered an 'oncometabolite', characteristic of cancers associated with mutated isocitrate dehydrogenases 1 or 2 (IDH1/2). We include procedures for determining quantitative robustness, and show results of these relating to the analysis of DL-2-hydroxyglutarate in cells, as well as in serum samples from patients with acute myeloid leukemia that contain the IDH1/2 mutation. This EISA-mass spectrometry protocol is a broadly applicable and low-cost approach for the quantification of small molecules that has been developed to work well for both single-quadrupole and time-of-flight mass analyzers.

Deep-sea organisms research oriented by deep-sea technologies development.

Deep-sea environment, characterized by high pressures, extremely high/low temperatures, limited photosynthesis-generated organic matter, darkness, and high levels of corrosion, is home to flourishing special ecosystems in the world. Here, we illustrate how the deep-sea equipment offers insights into the study of life in the deep sea based on the work in the past five decades. We first describe how organisms in the deep sea are studied, even though it is highly difficult to get access to such extreme environments. We then explain the role of deep-sea technologies in advancing research on the evolution of organisms in hydrothermal vents, cold seeps, seamounts, oceanic trenches, and whale falls from the following perspectives: biological diversity, mechanisms of environmental adaptation, biological evolution, and ecosystem connectivity. Finally, to better understand the function and service of deep-sea organisms, and further conserve the special creatures under anthropologic activity and climate change, we highlight the importance of innovative deep-sea technologies to promote cutting-edge research on deep-sea organisms, and note the remaining challenges and developing directions for deep-sea equipment.

First Evidence of Prenatal Exposure to Emerging Poly- and Perfluoroalkyl Substances Associated with E-Waste Dismantling: Chemical Structure-Based Placental Transfer and Health Risks.

Limited information is available about prenatal exposure to per- and polyfluoroalkyl substances (PFAS) in electronic waste (e-waste) recycling sites. In this study, we determined 21 emerging PFAS and 13 legacy PFAS in 94 paired maternal and cord serum samples collected from an e-waste dismantling site in Southern China. We found 6:2 fluorotelomer sulfonate (6:2 FTSA), 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA), and perfluorooctanephosphonate (PFOPA) as the major emerging PFAS, regardless of matrices, at median concentrations of 2.40, 1.78, and 0.69 ng/mL, respectively, in maternal serum samples, and 2.30, 0.73, and 0.72 ng/mL, respectively, in cord serum samples. Our results provide evidence that e-waste dismantling activities contribute to human exposure to 6:2 FTSA, 6:2 Cl-PFESA, and PFOPA. The trans-placental transfer efficiencies of emerging PFAS (0.42-0.94) were higher than that of perfluorooctanesulfonic acid (0.37) and were structure-dependent. The substitution of fluorine with chlorine or hydrogen and/or hydrophilic functional groups may alter trans-placental transfer efficiencies. Multiple linear regression analysis indicated significant associations between maternal serum concentrations of emerging PFAS and maternal clinical parameters, especially liver function and erythrocyte-related biomarkers. This study provides new insights into prenatal exposure to multiple PFAS in e-waste dismantling areas and the prevalence of emerging PFAS in people living near the sites.

A Pilot Nationwide Survey on the Concentrations of Neonicotinoids and Their Metabolites in Indoor Dust from China: Application for Human Exposure.

The present study assessed the residue levels of six parent neonicotinoids (p-NEOs) and four metabolites (m-NEOs) in indoor dust collected from 12 cities of China. Acetamiprid (ACE) and imidacloprid (IMI) were the predominated p-NEOs (detection rates: 98%) with the median values at 4.54 and 7.48 ng/g dry weight (dw), respectively. N-demethyl-acetamiprid (N-dm-ACE) was the most important m-NEO with the median value at 0.69 ng/g dw, while other m-NEOs were rarely detected (detection rates: < 15%). Significant correlation between ACE and thiacloprid (THD) was observed (p < 0.01), indicating their probably concurrent applications. ACE was significantly correlated to N-dm-ACE (p < 0.01), implicating the degradation of ACE in indoor environment. The estimated daily intake (EDIing) of NEOs via dust ingestion were far lower than the acceptable daily intake for NEOs. To our knowledge, this study provided a baseline nationwide investigation on the occurrence of NEOs in indoor dust of China.

Mechanisms of polystyrene microplastic degradation by the microbially driven Fenton reaction.

Natural hydroxyl radical (·OH) production, which partially occurs through the microbially driven Fenton reaction, can enhance the degradation of polystyrene microplastics (PS-MPs). However, ·OH causes damage to microorganisms, which might in turn restrain the microbially driven Fenton reaction. Thus, whether PS-MPs can be continuously degraded by the microbially driven Fenton reaction and how they are degraded are still unknown. A pure-culture system using Shewanella putrefaciens 200 was set up to explore the effect and mechanism of microbially driven Fenton reaction on PS-MP degradation. In a 14-day operation, ·OH produced by the microbially driven Fenton reaction could degrade PS-MPs with a weight loss of 6.1 ± 0.6% and an O/C ratio of 0.6 (v.s. 0.6 ± 0.1% and 0.1, respectively, in the ·OH quenched group). Benzene ring derivatives such as 2-isopropyl-5-methyl-1-heptanol and nonahexacontanoic acid were the main soluble products of PS-MP degradation. The ·OH-induced oxidative damage on microorganisms did not affect ·OH production significantly when there was timely replenishment of organic carbon sources to promote reproduction of microorganisms. Thus, PS-MPs can be continuously degraded by microbially driven Fenton reactions in natural alternating anaerobic-aerobic environments. This study also provides a new microbial technique for MP degradation that is different from previous technologies based on microbial plastic-degrading enzymes.

Accelerated lysine metabolism conveys kidney protection in salt-sensitive hypertension.

Hypertension and kidney disease have been repeatedly associated with genomic variants and alterations of lysine metabolism. Here, we combined stable isotope labeling with untargeted metabolomics to investigate lysine's metabolic fate in vivo. Dietary 13C6 labeled lysine was tracked to lysine metabolites across various organs. Globally, lysine reacts rapidly with molecules of the central carbon metabolism, but incorporates slowly into proteins and acylcarnitines. Lysine metabolism is accelerated in a rat model of hypertension and kidney damage, chiefly through N-alpha-mediated degradation. Lysine administration diminished development of hypertension and kidney injury. Protective mechanisms include diuresis, further acceleration of lysine conjugate formation, and inhibition of tubular albumin uptake. Lysine also conjugates with malonyl-CoA to form a novel metabolite Nε-malonyl-lysine to deplete malonyl-CoA from fatty acid synthesis. Through conjugate formation and excretion as fructoselysine, saccharopine, and Nε-acetyllysine, lysine lead to depletion of central carbon metabolites from the organism and kidney. Consistently, lysine administration to patients at risk for hypertension and kidney disease inhibited tubular albumin uptake, increased lysine conjugate formation, and reduced tricarboxylic acid (TCA) cycle metabolites, compared to kidney-healthy volunteers. In conclusion, lysine isotope tracing mapped an accelerated metabolism in hypertension, and lysine administration could protect kidneys in hypertensive kidney disease.

A nationwide survey of 20 legacy brominated flame retardants in indoor dust from China: continuing occurrence, national distribution, and implication for human exposure.

Despite the restrictions on polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDDs), these chemicals are still ubiquitous environmental pollutants. In this study, we measured the concentrations and profiles of 17 PBDE congeners and 3 HBCDD isomers in indoor dust samples collected from 23 provinces and cities across China. The summed concentrations of PBDEs (Σ17PBDEs) ranged from 4.19 to 817 ng/g, with an average of 171 ± 184 ng/g. BDE-209 was the most abundant congener. The concentrations of HBCDDs ranged from 6.65 to 1335 ng/g, with an average of 236 ± 324 ng/g. Unlike commercial HBCDD formulations, α-HBCDD was the predominant isomer in the indoor dust samples analyzed. Geographical distributions showed that the concentrations of PBDEs and HBCDDs varied significantly among different regions. Higher PBDE and HBCDD levels were observed in samples from eastern coastal and economically developed regions. Further, we estimated the daily intakes of PBDEs and HBCDDs through the routes of dust ingestion and dust dermal absorption for different age groups. Dust dermal absorption is an unneglectable exposure pathway to PBDEs and HBCDs for the Chinese population. Among the age groups, infants had the highest exposure via dust dermal absorption, and toddlers had the highest exposure via dust ingestion. Compared with the threshold values, the exposure doses of PBDEs and HBCDDs are unlikely to pose significant health concerns for both infants and adults in China. This is the first national survey of PBDEs and HBCDDs in indoor dust samples across China after the restriction.

Effects of long-term and low-concentration exposures of benzene and formaldehyde on mortality of Drosophila melanogaster.

Single-chemical thresholds cannot comprehensively evaluate the risk of chemical mixture exposure in indoor air. Moreover, a large number of researches have focused on short-term and high-concentration co-exposure scenarios related to different species, based on diverse endpoints, which hampers the application and improvement of existing risk evaluation models of chemical mixture exposures. More importantly, current risk evaluation models are not user-friendly for construction practitioners who do not have sufficient toxicological knowledge. Therefore, in this study, an inhalation experiment system and a hazard index (HI) were developed to investigate the risks associated with low-concentration and long-term inhalation exposure scenarios of formaldehyde and benzene, individually and combined, based on Drosophila melanogaster mortality. The results showed that the system exhibited good reproducibility in providing stable exposure concentrations during D. melanogaster life cycle. Furthermore, in a range of experimental concentrations, the interaction between formaldehyde and benzene was additive or synergistic, which was concentration- and ratio-dependent. This study is of great significance in harmonising and providing toxicity data under long-term and low-concentration exposure scenarios, which is beneficial for establishing a new user-friendly risk evaluation model for indoor chemical mixture exposures. It should be noted that the proposed HI value could indicate the hazard degrees of long-term inhalation exposures of formaldehyde and benzene, individually and combined, to D. melanogaster. However, the applicability of this index requires further experiments to evaluate the exposure risks of other volatile organic compounds (VOCs) to D. melanogaster.

Placental transfer of bisphenol diglycidyl ethers (BDGEs) and its association with maternal health in a population in South of China.

Despite high production and usage, little is known about exposure to bisphenol diglycidyl ethers (BDGEs) and their derivatives in pregnant women and fetuses. In this study, we determined nine BDGEs in 106 paired maternal and cord serum samples collected from e-waste dismantling sites in South of China. Bisphenol A bis (2,3-dihydroxypropyl) glycidyl ether (BADGE·2H2O), bisphenol A (3-chloro-2-hydroxypropyl) (2,3-dihydroxypropyl) glycidyl ether (BADGE·HCl·H2O), and bisphenol F diglycidyl ether (BFDGE) were the major BDGEs, with median concentrations of 0.57, 4.07, and 1.60 ng/mL, respectively, in maternal serum, and of 3.58, 5.61, and 0.61 ng/mL, respectively, in cord serum. The transplacental transfer efficiencies (TTEs) were estimated for BDGEs found in samples, and median values were in the range of 0.98 (BFDGE) to 5.91 (BADGE·2H2O). Our results suggested that passive diffusion plays a role in the placental transfer of BADGE·HCl·H2O and BFDGE, whereas several mechanisms contribute to the high accumulation of BADGE·2H2O in cord serum. Multiple linear regression analysis indicated significant associations between maternal serum concentrations of BDGEs and blood clinical biomarkers, especially those related to liver injuries, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and adenosine deaminase (ADA) (P < 0.05). To our knowledge, this is the first study to report the occurrence of BDGEs in paired maternal-fetal serum samples and provide new insights into prenatal and fetal exposures. The newly discovered TTEs in maternal-fetal pairs contribute to a fuller inventory of the transmission activity of pollutants in the human body, ultimately adding to a more significant comprehensive risk evaluation.

Proteomics with Enhanced In-Source Fragmentation/Annotation: Applying XCMS-EISA Informatics and Q-MRM High-Sensitivity Quantification.

Enhanced in-source fragmentation/annotation (EISA) has recently been shown to produce fragment ions that match tandem mass spectrometry data across a wide range of small molecules. EISA has been developed to facilitate data-dependent acquisition (DDA), data-independent acquisiton (DIA), and multiple-reaction monitoring (MRM), enabling molecular identifications in untargeted metabolomics and targeted quantitative single-quadrupole MRM (Q-MRM) analyses. Here, EISA has been applied to peptide-based proteomic analysis using optimized in-source fragmentation to generate fragmentation patterns for a mixture of 38 peptides, which were comparable to the b- and y-type fragment ions typically observed in tandem MS experiments. The optimal in-source fragmentation conditions at which high-abundance peptide fragments and precursor ions coexist were compared with automated data-dependent acquisition (DDA) in the same quadrupole time-of-flight (QTOF-MS) mass spectrometer, generating a significantly higher fragment percentage of peptides from both singly and doubly charged b- and y-type fragment (b+, y+, b2+, and y2+) ions. Higher fragment percentages were also observed for these fragment ion series over linear ion trap instrumentation. An XCMS-EISA annotation/deconvolution program was developed, making use of the retention time and peak shape continuity between precursor fragment ions, to perform automated proteomic data analysis on the enhanced in-source fragments. Post-translational modification (PTM) characterization on peptides was demonstrated with EISA, producing fragment ions corresponding to a neutral loss of phosphoric acid with greater intensity than observed with DDA on a QTOF-MS. Moreover, Q-MRM demonstrated the ability to use EISA for peptide quantification. The availability of more sophisticated in-source fragmentation informatics, beyond XCMS-EISA, will further enable EISA for sensitive autonomous identification and Q-MRM quantitative analyses in proteomics.

Occurrence of Phthalates in Bottled Drinks in the Chinese Market and Its Implications for Dietary Exposure.

Ubiquitous occurrences of phthalic acid esters (PAEs) or phthalates in a variety of consumer products have been demonstrated. Nevertheless, studies on their occurrence in various types of bottled drinks are limited. In this study, fifteen PAEs were analyzed in six categories of bottled drinks (n = 105) collected from the Chinese market, including mineral water, tea drinks, energy drinks, juice drinks, soft drinks, and beer. Among the 15 PAEs measured, DEHP was the most abundant phthalate with concentrations ranging from below the limit of quantification (LOQ) to 41,000 ng/L at a detection rate (DR) of 96%, followed by DIBP (DR: 88%) and DBP (DR: 84%) with respective concentration ranges of below LOQ to 16,000 and to 4900 ng/L. At least one PAE was detected in each drink sample, and the sum concentrations of 15 PAEs ranged from 770 to 48,004 ng/L (median: 6286 ng/L). Significant differences with respect to both PAE concentrations and composition profiles were observed between different types of bottled drinks. The median sum concentration of 15 PAEs in soft drinks was over five times higher than that detected in mineral water; different from other drink types. Besides DEHP, DBIP, and DBP, a high concentration of BMEP was also detected in a tea drink. The estimated daily dietary intake of phthalates (EDIdrink) through the consumption of bottled drinks was calculated based on the concentrations measured and the daily ingestion rates of bottled drink items. The EDIdrink values for DMP, DEP, DIBP, DBP, BMEP, DAP, BEEP, BBP, DCP, DHP, BMPP, BBEP, DEHP, DOP, and DNP through the consumption of bottled mineral water (based on mean concentrations) were 0.45, 0.33, 12.5, 3.67, 2.10, 0.06, 0.32, 0.16, 0.10, 0.09, 0.05, 0.81, 112, 0.13, and 0.20 ng/kg-bw/d, respectively, for Chinese adults. Overall, the EDIdrink values calculated for phthalates through the consumption of bottled drinks were below the oral reference doses suggested by the United States Environmental Protection Agency (U.S. EPA).

Phthalate metabolites: Characterization, toxicities, global distribution, and exposure assessment.

Phthalates are plasticizers in various products and regarded as endocrine disruptors due to their anti-androgen effects. Environmental occurrence and toxicities of parent phthalates have been widely reported, while the current state of knowledge on their metabolites is rarely summarized. Based on the available literature, the present review mainly aims to 1) characterize the potential metabolites of phthalates (mPAEs) using the pharmacokinetics evidences acquired via animal or human models; 2) examine the molecular and cellular mechanism involved in toxicity for mPAEs; 3) investigate the exposure levels of mPAEs in different human specimens (e.g., urine, blood, seminal fluid, breast milk, amniotic fluid and others) across the globe; 4) discuss the models and related parameters for phthalate exposure assessment. We suggest there is subtle difference in toxic mechanisms for mPAEs compared to their parent phthalates due to their alternative chemical structures. Human monitoring studies performed in Asia, America and Europe have provided the population exposure baseline levels for typical phthalates in different regions. Urine is the preferred matrix than other specimens for phthalate exposure study. Among ten urinary mPAEs, the largest proportions of di-(2-ethylhexyl) phthalate (DEHP) metabolites (40%), monoethyl phthalate (mEP) (43%) and DEHP metabolites/mEP (both 29%) were observed in Asia, America and Europe respectively, and mono-5-carboxy-2-ethypentyl phthalate was the most abundant compounds among DEHP metabolites. Daily intakes of phthalates can be accurately calculated via urinary mPAEs if the proper exposure parameters were determined. Further work should focus on combining epidemiological and biological evidences to establish links between phthalates exposure and biological phenotypes. More accurate molar fractions (FUE) of the urinary excreted monoester related to the ingested diesters should be collected in epidemiological or pharmacokinetic studies for different population.

Deciphering Microbial Metal Toxicity Responses via Random Bar Code Transposon Site Sequencing and Activity-Based Metabolomics.

To uncover metal toxicity targets and defense mechanisms of the facultative anaerobe Pantoea sp. strain MT58 (MT58), we used a multiomic strategy combining two global techniques, random bar code transposon site sequencing (RB-TnSeq) and activity-based metabolomics. MT58 is a metal-tolerant Oak Ridge Reservation (ORR) environmental isolate that was enriched in the presence of metals at concentrations measured in contaminated groundwater at an ORR nuclear waste site. The effects of three chemically different metals found at elevated concentrations in the ORR contaminated environment were investigated: the cation Al3+, the oxyanion CrO42-, and the oxycation UO22+. Both global techniques were applied using all three metals under both aerobic and anaerobic conditions to elucidate metal interactions mediated through the activity of metabolites and key genes/proteins. These revealed that Al3+ binds intracellular arginine, CrO42- enters the cell through sulfate transporters and oxidizes intracellular reduced thiols, and membrane-bound lipopolysaccharides protect the cell from UO22+ toxicity. In addition, the Tol outer membrane system contributed to the protection of cellular integrity from the toxic effects of all three metals. Likewise, we found evidence of regulation of lipid content in membranes under metal stress. Individually, RB-TnSeq and metabolomics are powerful tools to explore the impact various stresses have on biological systems. Here, we show that together they can be used synergistically to identify the molecular actors and mechanisms of these pertubations to an organism, furthering our understanding of how living systems interact with their environment. IMPORTANCE Studying microbial interactions with their environment can lead to a deeper understanding of biological molecular mechanisms. In this study, two global techniques, RB-TnSeq and activity metabolomics, were successfully used to probe the interactions between a metal-resistant microorganism, Pantoea sp. strain MT58, and metals contaminating a site where the organism can be located. A number of novel metal-microbe interactions were uncovered, including Al3+ toxicity targeting arginine synthesis, which could lead to a deeper understanding of the impact Al3+ contamination has on microbial communities as well as its impact on higher-level organisms, including plants for whom Al3+ contamination is an issue. Using multiomic approaches like the one described here is a way to further our understanding of microbial interactions and their impacts on the environment overall.