An experimental and theoretical study on mechanistic insights into urolithin-based ratiometric fluorescent probe for instant quantitative detection of fluoride ions.

Fluoride detection has been playing an important role in chemical, biological, and medicinal field, especially for keeping physical health and resisting environmental pollution. Herein, a urolithin B fluorescent probe has been successfully developed with good sensitivity, selectivity, anti-interference ability. The low limit of detection (LOD) refers to 0.156 µM, and the instant response time to F- is less than 1 s. The probe is suitable for quantitatively and qualitatively ratiometric detection for F- in solution with two distinct emission bands at 425 (blue) and 566 nm (orange), with the coordinate change of CIE from (0.38, 0.41) to (0.22, 0.11). Urolithin B displayed a remarkable ratiometric fluorescence response towards F-. The detection mechanistic was further proposed by NMR and electronic spectroscopic experiments combining with time-dependent density functional theoretical calculation.

Interactions between H2O2 and dissolved organic matter during granular activated carbon-based residual H2O2 quenching from the upstream UV/H2O2 process.

Granular activated carbon (GAC) filtration can be employed to synchronously quench residual H2O2 from the upstream UV/H2O2 process and further degrade dissolved organic matter (DOM). In this study, rapid small-scale column tests (RSSCTs) were performed to clarify the mechanisms underlying the interactions between H2O2 and DOM during the GAC-based H2O2 quenching process. It was observed that GAC can catalytically decompose H2O2, with a long-lasting high efficiency (>80% for approximately 50,000 empty-bed volumes). DOM inhibited GAC-based H2O2 quenching via a pore-blocking effect, especially at high concentrations (10 mg/L), with the adsorbed DOM molecules being oxidized by the continuously generated ·OH; this further deteriorated the H2O2 quenching efficiency. In batch experiments, H2O2 could enhance DOM adsorption by GAC; however, in RSSCTs, it deteriorated DOM removal. This observation could be attributed to the different ·OH exposure in these two systems. It was also observed that aging with H2O2 and DOM altered the morphology, specific surface area, pore volume, and the surface functional groups of GAC, owing to the oxidation effect of H2O2 and ·OH on the GAC surface as well as the effect of DOM. Additionally, the changes in the content of persistent free radicals in the GAC samples were insignificant following different aging processes. This work contributes to enhancing understanding regarding the UV/H2O2-GAC filtration scheme, and promoting the application in drinking water treatment.

Electron-transfer-based peroxymonosulfate activation on defect-rich carbon nanotubes: Understanding the substituent effect on the selective oxidation of phenols.

Nanocarbon-based persulfate oxidation technologies are promising for green elimination of phenolic pollutants. Previous studies revealed the electron transfer via defective carbon nanotube (CNTs) for selective oxidation of various phenols. However, an underlying relationship between the molecular structure of phenols and the selectivity of electron transfer-induced oxidation has not been well understood. Herein, we report that defect-rich CNTs could initiate electron-transfer regime from phenols to peroxymonosulfate (PMS), resulting in the efficient degradation of phenols. Further studies uncover a distinctive substituent group-dependent selective oxidation of phenols via the CNT-mediated electron transfer process. Specifically, the degradation rate of para-substituted phenols with electron-donating groups (e.g., -NH2 and -OCH3) is faster than those with electron-withdrawing groups (e.g., -NO2 and -COOH). For a kind of substituted phenols, the substituent position has a great influence on the phenols degradation and their degradation rates follow this sequence: para > ortho > meta -position. Besides, increasing the number of the substituent group can accelerate the degradation of substituted phenols. This study elucidates the substituent effect on the electron transfer-dominated selective oxidation of phenols for the first time, which guides the application of carbon/persulfate system for the targeted remediation of phenols-polluted wastewater.

The discovery of a key prenyltransferase gene assisted by a chromosome-level Epimedium pubescens genome.

Epimedium pubescens is a species of the family Berberidaceae in the basal eudicot lineage, and a main plant source for the traditional Chinese medicine "Herba Epimedii". The current study achieved a chromosome-level genome assembly of E. pubescens with the genome size of 3.34 Gb, and the genome guided discovery of a key prenyltransferase (PT) in E. pubescens. Our comparative genomic analyses confirmed the absence of Whole Genome Triplication (WGT-γ) event shared in core eudicots and further revealed the occurrence of an ancient Whole Genome Duplication (WGD) event approximately between 66 and 81 Million Years Ago (MYA). In addition, whole genome search approach was successfully applied to identify 19 potential flavonoid PT genes and an important flavonoid PT (EpPT8) was proven to be an enzyme for the biosynthesis of medicinal compounds, icaritin and its derivatives in E. pubescens. Therefore, our results not only provide a good reference genome to conduct further molecular biological studies in Epimedium genus, but also give important clues for synthetic biology and industrial production of related prenylated flavonoids in future.

A Novel 3-O-rhamnoside: 2″-O-xylosyltransferase Responsible for Terminal Modification of Prenylflavonol Glycosides in Epimedium pubescens Maxim.

Prenylated flavonol glycosides in Epimedium plants, as key medicinal components, are known to have great pharmaceutical activities for human health. Among the main prenylated flavonol glycosides, the modification mechanism of different sugar moieties is still not well understood. In the current study, a novel prenylated flavonol rhamnoside xylosyltransferase gene (EpF3R2″XylT) was cloned from E. pubescens, and the enzymatic activity of its decoding proteins was examined in vitro with different prenylated flavonol rhamnoside substrates and different 3-O-monosaccharide moieties. Furthermore, the functional and structural domains of EpF3R2″XylT were analyzed by bioinformatic approaches and 3-D protein structure remodeling. In summary, EpF3R2″XylT was shown to cluster with GGT (glycosyltransferase that glycosylates sugar moieties of glycosides) through phylogenetic analysis. In enzymatic analysis, EpF3R2″XylT was proven to transfer xylose moiety from UDP-xylose to prenylated flavonol rhamnoside at the 2″-OH position of rhamnose. The analysis of enzymatic kinetics showed that EpF3R2″XylT had the highest substrate affinity toward icariin with the lowest Km value of 75.96 ± 11.91 mM. Transient expression of EpF3R2″XylT in tobacco leaf showed functional production of EpF3R2″XylT proteins in planta. EpF3R2″XylT was preferably expressed in the leaves of E. pubescens, which is consistent with the accumulation levels of major prenylflavonol 3-O-triglycoside. The discovery of EpF3R2″XylT will provide an economical and efficient alternative way to produce prenylated flavonol trisaccharides through the biosynthetic approach.

Spectroscopic and mechanistic insights into solvent mediated excited-state proton transfer and aggregation-induced emission: introduction of methyl group onto 2-(o-hydroxyphenyl)benzoxazole.

Excited-state intramolecular proton transfer (ESIPT) reaction plays an important role in biology, materials, and other related fields. The ESIPT-based compounds has been proved to improve effectively fluorescence quantum yield, red-shifted emission, and wide separation between absorption and emission wavelengths (large Stokes shift, LSS). A solvatochromic benzoxazole-based probe, 2-(2-hydroxy-5-methylphenyl)benzoxazole(HBO-pCH3), exhibited a typical dual fluorescence phenomenon via the ESIPT reaction in non-polar and weakly polar solvents. The emission bands of normal* (∼370 nm) and tautomer* (∼500 nm) forms were identified and assigned, based on fluorescence spectroscopy and quantum chemical theoretical calculations. Solvatochromism confirmed ESIPT reaction inhibition by solvent polarity and intermolecular hydrogen bonding. The intramolecular reversal in combination with time-dependent density functional theoretical calculations revealed an emission-strengthening mechanism of ESIPT, coupled with aggregation-induced emission (AIE) (in mixed water/methanol solvents). Thus, this strategy provides an insight into designing potential "ESIPT + AIE" fluorescent sensors.

New 8-prenylated quercetin glycosides from the flowers of Epimedium acuminatum and their testosterone production-promoting activities.

Phytochemical investigation was carried out for the flowers of Epimedium acuminatum Franchet. by first conducting LC-MS analysis, leading to the identification of 32 compounds. Furthermore, guided by LC-MS profiling, three new 8-prenylated quercetin glycosides (3'-hydroxylikarisoside C, 3'-hydroxylepimedoside E, 3'-hydroxyldiphylloside B), one new anthocyanin (delphinidin-3-O-p-coumaroyl-sophoroside) and six known compounds were isolated from the flowers of E. acuminatum for the first time, and their structures were characterized based on spectroscopic methods including 1D and 2D NMR, and HRESIMS. Combining our discoveries and literature survey, a revised classification of Epimedium flavonols was proposed as Type A (8-prenylated kaempferol based), which was further subdivided into subtype icaritin and subtype demethylicaritin, and Type B (8-prenylated quercetin based), which was further subdivided into subtype 3'-hydroxylicaritin and subtype 3'-hydroxyldemethylicaritin. The structure-activity relationship (SAR) study was carried out by comparing testosterone production-promoting activities of all the new compounds along with nine related Epimedium flavonols, revealing that the new 8-prenylated quercetin glycosides (subtype 3'-hydroxyldemethylicaritin in Type B) exhibited lower testosterone production-promoting activities in rat primary Leydig cells than Epimedium flavonols of subtype demethylicaritin in Type A, but possessed higher activities than the Epimedium flavonols of subtype icaritin in Type A. These results suggested that either methylation at C-4' position or hydroxylation at C-3' position of ring B could significantly reduce the testosterone production-promoting activities of Epimedium flavonols.

Genome-wide analysis of UGT gene family identified key gene for the biosynthesis of bioactive flavonol glycosides in Epimedium pubescens Maxim.

Epimedium pubescens Maxim. is a well-known traditional Chinese medicinal herb with flavonol glycosides as the major pharmaceutically active compounds. UDP-glycosyltransferases (UGTs) are a group of enzymes responsible for the glycosylation of flavonoid glycosides. In this study, a genome-wide analysis was performed to identify UGT family genes in E. pubescens. As a result, a total of 339 putative UGT genes were identified, which represents the largest UGT gene family known thus far, implying a significant expansion of the UGT gene family in E. pubescens. All EpUGTs were unevenly distributed across six chromosomes, and they were classified into 17 major groups. The expression profiles showed that UGT genes were differentially expressed in roots, leaves, flowers, shoots and fruits. In particular, several EpUGTs were highly induced by high light intensity, which was consistent with the accumulation level of bioactive flavonoids in E. pubescens. Six UGT79 genes that were preferentially expressed in roots or leaves were successfully expressed in E. coli, and only the recombinant EpGT60 protein was found to be active toward 8-prenylkaempferol and icaritin to produce the key bioactive compounds baohuoside II and baohuoside I. The optimal temperature, pH, k m and V max were determined for the recombinant EpGT60 protein. In addition, expression of recombinant EpGT60 in E. coli cell culture led to successful production of baohuoside II when fed 8-prenylkaempferol. Our study provides a foundation for further functional characterization of UGT genes in E. pubescens and provides key candidate genes for bioengineering bioactive flavonoids in E. pubescens.

The complete chloroplast genome of Epimedium xichangense Y. J. Zhang (Berberidaceae).

Epimedium xichangense, a critically endangered herb with limited population, mainly distributes in Sichuan province, China. In our study, we obtained the complete chloroplast genome of E. xichangense with a length of 158,955 bp, including a large single copy region of 86,478 bp, small single copy region of 17,027 bp, and a pair of inverted repeat regions of 27,725 bp. The GC content in the whole chloroplast genome of E. xichangense is 38.81%. Among the 112 unique genes in the circular genome, 30 tRNA, four rRNA and 78 protein-coding genes were successfully annotated. We constructed the Maximum likelihood (ML) tree with 26 species, and came to the conclusion that E. xichangense was phylogenetically closely related to E. acuminatum and E. chlorandrum.

Roles of hydroxylamine and hydrazine in the in-situ recovery of one-stage partial nitritation-anammox process: Characteristics and mechanisms.

Nitrate built-up is a serious operational difficulty in one-stage partial nitritation anammox (PN/A) process. To investigate an effective method for in-situ restoration, hydroxylamine (NH2OH) and hydrazine (N2H4) of 2 mgN/L were dosed in PN/A process with nitrate built-up in a comparative study. NH2OH treatment showed better performances on TN removal and nitrate reduction than N2H4 and blank control. Through 104 days' addition of NH2OH, MRNN (mole ratio of NO3--N production to NH4+-N removal) was decreased from 70% to 19.91%; TN removal was increased from 0.01 to 0.18 kgN/(m3 d). After stopping the chemical addition, nitrate rebounded for N2H4 treatment, but the restoration effect was stable and persistent for NH2OH. NH2OH addition resulted in a low reductive potential (-250 mV) and exerted strong inhibitions on nitrite oxidizing bacteria activities. Additionally, rapid enhancement of ammonia oxidizing bacteria activities, functional gene (hao) and Nitrosomonas gave rise to the restoration of PN/A with NH2OH addition.

Identification and prospective stability of electronic nose (eNose)-derived inflammatory phenotypes in patients with severe asthma.

BACKGROUND: Severe asthma is a heterogeneous condition, as shown by independent cluster analyses based on demographic, clinical, and inflammatory characteristics. A next step is to identify molecularly driven phenotypes using "omics" technologies. Molecular fingerprints of exhaled breath are associated with inflammation and can qualify as noninvasive assessment of severe asthma phenotypes. OBJECTIVES: We aimed (1) to identify severe asthma phenotypes using exhaled metabolomic fingerprints obtained from a composite of electronic noses (eNoses) and (2) to assess the stability of eNose-derived phenotypes in relation to within-patient clinical and inflammatory changes. METHODS: In this longitudinal multicenter study exhaled breath samples were taken from an unselected subset of adults with severe asthma from the U-BIOPRED cohort. Exhaled metabolites were analyzed centrally by using an assembly of eNoses. Unsupervised Ward clustering enhanced by similarity profile analysis together with K-means clustering was performed. For internal validation, partitioning around medoids and topological data analysis were applied. Samples at 12 to 18 months of prospective follow-up were used to assess longitudinal within-patient stability. RESULTS: Data were available for 78 subjects (age, 55 years [interquartile range, 45-64 years]; 41% male). Three eNose-driven clusters (n = 26/33/19) were revealed, showing differences in circulating eosinophil (P = .045) and neutrophil (P = .017) percentages and ratios of patients using oral corticosteroids (P = .035). Longitudinal within-patient cluster stability was associated with changes in sputum eosinophil percentages (P = .045). CONCLUSIONS: We have identified and followed up exhaled molecular phenotypes of severe asthma, which were associated with changing inflammatory profile and oral steroid use. This suggests that breath analysis can contribute to the management of severe asthma.

Who contributes more to N2O emission during sludge bio-drying with two different aeration strategies, nitrifiers or denitrifiers?

Global warming effects have drawn more and more attention to studying all sources and sinks of nitrous oxide (N2O). Sludge bio-drying, as an effective sludge treatment technology, is being adopted worldwide. In this study, two aeration strategies (piles I and II) were compared to investigate the primary contributors to N2O emission during sludge bio-drying through studying the evolution of functional genes involved in nitrification (amoA, hao, and nxrA) and denitrification (narG, nirS, nirK, norB, and nosZ) by quantitative PCR (qPCR). Results showed that the profile of N2O emission can be divided into three stages, traditional denitrification contributed largely to N2O emission at stage I (days 1-5), but N2O emission mainly happened at stage II (days 5-14) due to nitrifier denitrification and NH2OH accumulation by ammonia-oxidizing bacteria (AOB), accounting for 51.4% and 58.2% of total N2O emission for piles I and II, respectively. At stage III (days 14-21), nitrifier denitrification was inhibited because sludge bio-drying proceeded mainly by the physical aeration, thus N2O emission decreased and changed little. The improved aeration strategy availed pile I to reduce N2O emission much especially at stages II and III, respectively. These results indicated that nitrifier denitrification by AOB and biological NH2OH oxidation due to AOB made more contribution to N2O emission, and aeration strategy was crucial to mitigate N2O emission during sludge bio-drying.

Exhaled breath metabolomics as a noninvasive diagnostic tool for acute respiratory distress syndrome.

There is a need for biological markers of the acute respiratory distress syndrome (ARDS). Exhaled breath contains hundreds of metabolites in the gas phase, some of which reflect (patho)physiological processes. We aimed to determine the diagnostic accuracy of metabolites in exhaled breath as biomarkers of ARDS. Breath from ventilated intensive care unit patients (n=101) was analysed using gas chromatography and mass spectrometry during the first day of admission. ARDS was defined by the Berlin definition. Training and temporal validation cohorts were used. 23 patients in the training cohort (n=53) had ARDS. Three breath metabolites, octane, acetaldehyde and 3-methylheptane, could discriminate between ARDS and controls with an area under the receiver operating characteristic curve (AUC) of 0.80. Temporal external validation (19 ARDS cases in a cohort of 48) resulted in an AUC of 0.78. Discrimination was insensitive to adjustment for severity of disease, a direct or indirect cause of ARDS, comorbidities, or ventilator settings. Combination with the lung injury prediction score increased the AUC to 0.91 and improved net reclassification by 1.17. Exhaled breath analysis showed good diagnostic accuracy for ARDS, which was externally validated. These data suggest that exhaled breath analysis could be used for the diagnostic assessment of ARDS.

[Distribution and removal of anaerobic antibiotic resistant bacteria during mesophilic anaerobic digestion of sewage sludge].

Sewage sludge is one of the major sources that releasing antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARG) into the environment since it contains large amount of ARB, but there is little information about the fate of the anaerobic ARB in the anaerobic digestion of sewage sludge. Therefore, the distribution, removal and seasonal changes of tetracycline and ß-lactam antibiotics resistant bacteria in the mesophilic egg-shaped digesters of a municipal wastewater treatment plant were investigated for one year in this study. Results showed that there were higher amounts of ARB and higher resistance rate of ß-lactam antibiotics than that of tetracycline antibiotics in the sewage sludge. All ARB could be significantly reduced during the mesophilic anaerobic digestion process by 1.48-1.64 log unit (P < 0.05). Notably, the ampicillin and cephalothin resistance rates were significantly increased after anaerobic digestion by 12.0% and 14.3%, respectively (P < 0.05). The distribution of ARB in the sewage sludge had seasonal change characteristics. Except for chlorotetracycline resistant bacteria, there were more ARB in the sewage sludge in cold season than in warm season (P < 0.05).

A simple breath sampling method in intubated and mechanically ventilated critically ill patients.

Volatile organic compounds (VOCs) in breath may serve as biomarkers of pulmonary infection or inflammation. We developed and validated a new breath sampling method for VOC analysis in ventilated patients. Breath was collected from the ventilatory circuit using cheap disposables. VOCs were identified by gas-chromatography and mass-spectrometry (GC-MS) at various minute volumes during ventilation of an artificial lung (in vitro) and ventilated patients (in vivo). Sixty-four VOCs emendated from the ventilator and tubing. Their concentrations had an inverse correlation with minute volume in in vitro experiments (median correlation coefficient: -0.61 [25-75th percentile: -0.66 to -0.43]). Forty-four of these "ventilator-associated VOCs" were also observed in vivo, without correlations with minute volume. In vivo experiments showed that only positive end-expiratory pressure influenced the concentration of breath VOCs. The sampling method was highly reproducible (median intra-class correlation 0.95 [25-75th percentile: 0.87-0.97]). In conclusion, a novel, simple and repeatable sampling method was developed and validated for capturing exhaled VOCs in ventilated patients, which could allow for large-scale breath analysis in clinical studies.