Exposure of benzo[a]pyrene induces HCC exosome-circular RNA to activate lung fibroblasts and trigger organotropic metastasis.

BACKGROUND: Benzo[a]pyrene (B[a]P), a carcinogen pollutant produced by combustion processes, is present in the western diet with grilled meats. Chronic exposure of B[a]P in hepatocellular carcinoma (HCC) cells promotes metastasis rather than primary proliferation, implying an unknown mechanism of B[a]P-induced malignancy. Given that exosomes carry bioactive molecules to distant sites, we investigated whether and how exosomes mediate cancer-stroma communications for a toxicologically associated microenvironment. METHOD: Exosomes were isolated from B[a]P stimulated BEL7404 HCC cells (7404-100Bap Exo) at an environmental relevant dose (100 nmol/L). Lung pre-education animal model was prepared via injection of exosomes and cytokines. The inflammatory genes of educated lungs were evaluated using quantitative reverse transcription PCR array. HCC LM3 cells transfected with firefly luciferase were next injected to monitor tumor burdens and organotropic metastasis. Profile of B[a]P-exposed exosomes were determined by ceRNA microarray. Interactions between circular RNA (circRNA) and microRNAs (miRNAs) were detected using RNA pull-down in target lung fibroblasts. Fluorescence in situ hybridization and RNA immunoprecipitation assay was used to evaluate the "on-off" interaction of circRNA-miRNA pairs. We further developed an adeno-associated virus inhalation model to examine mRNA expression specific in lung, thereby exploring the mRNA targets of B[a]P induced circRNA-miRNA cascade. RESULTS: Lung fibroblasts exert activation phenotypes, including focal adhesion and motility were altered by 7404-100Bap Exo. In the exosome-educated in vivo model, fibrosis factors and pro-inflammatory molecules of are up-regulated when injected with exosomes. Compared to non-exposed 7404 cells, circ_0011496 was up-regulated following B[a]P treatment and was mainly packaged into 7404-100Bap Exo. Exosomal circ_0011496 were delivered and competitively bound to miR-486-5p in recipient fibroblasts. The down-regulation of miR-486-5p converted fibroblast to cancer-associated fibroblast via regulating the downstream of Twinfilin-1 (TWF1) and matrix metalloproteinase-9 (MMP9) cascade. Additionally, increased TWF1, specifically in exosomal circ_0011496 educated lungs, could promote cancer-stroma crosstalk via activating vascular endothelial growth factor (VEGF). These modulated fibroblasts promoted endothelial cells angiogenesis and recruited primary HCC cells invasion, as a consequence of a pre-metastatic niche formation. CONCLUSION: We demonstrated that B[a]P-induced tumor exosomes can deliver circ_0011496 to activate miR-486-5p/TWF1/MMP9 cascade in the lung fibroblasts, generating a feedback loop that promoted HCC metastasis.

The mechanisms of ·OH formation in MnO2 and oxalate system: Implication for ATZ removal.

Manganese oxides (MnO2) are commonly prevalent in groundwater, sediment and soil. In this study, we found that oxalate (H2C2O4) dissolved MnO2, leading to the formation of Mn(II)/(III), CO2(aq) and reactive oxygen species (·CO2-/O2·-/H2O2/·OH). Notably, CO2(aq) played a crucial role in ·OH formation, contributing to the degradation of atrazine (ATZ). To elucidate underneath mechanisms, a series of reactions with different gas-liquid ratios (GLR) were conducted. At the GLR of 0.3, 3.76, and + ∞ 79.4 %, 5.32 %, and 5.28 % of ATZ were eliminated, in which the cumulative ·OH concentration was 39.6 µM, 8.11 µM, and 7.39 µM and the cumulative CO2(aq) concentration was 11.2 mM, 4.7 mM, and 2.8 mM, respectively. The proposed reaction pathway was that CO2(aq) participated in the formation of a ternary complex [C2O4-Mn(II)-HCO4·3 H2O]-, which converted to a transition state (TS) as [C2O4-Mn(II)-CO3-OH·3 H2O]-, then decomposed to a complex radical [C2O4-Mn(II)-CO3·3 H2O]·- and ·OH after electron transfer within TS. It was novel to discover the role of CO2(aq) for ·OH yielding during MnO2 dissolution by H2C2O4. This finding helps revealing the overlooked processes that CO2(aq) influenced the fate of ATZ or other organic compounds in environment and providing us ideas for new technique development in contaminant remediation. ENVIRONMENTAL IMPLICATION: Manganese oxides and oxalate are common in soil, sediment and water. Their interactions could induce the formation of Mn(II)/(III), CO2(aq) and ·CO2-/O2·-/H2O2. This study found that atrazine could be effectively removed due to ·OH radicals under condition of high CO2(aq) concentration. The concentrations of Mn (0.0002-8.34 mg·L-1) and CO2(aq) (15-40 mg·L-1) were high in groundwater, and the surface water or rainfall seeps into groundwater and bring organic acids, which might promote the ·OH formation. The results might explain the missing steps of herbicides transformation in these environments and be helpful in developing new techniques in remediation in future.

A review of the subgenera Carinichelonus, Microchelonus, Parachelonus and Stylochelonus of the genus Chelonus Panzer (Braconidae: Cheloninae) with descriptions of twenty-one new species from China.

Three subgenera Microchelonus Szpligeti, 1908 s. str., Parachelonus Tobias, 1995 and Stylochelonus Helln, 1958 are newly recorded from China, 21 new species, viz., C. (M.) adiazetos sp. nov., C. (M.) aequus sp. nov., C. (M.) brachykeraiatus sp. nov., C. (M.) bullatus sp. nov., C. (M.) clivus sp. nov., C. (M.) crassitibialis sp. nov., C. (M.) cyclotus sp. nov., C. (M.) erugatus sp. nov., C. (M.) illatus sp. nov., C. (M.) leious sp. nov., C. (M.) linzhiensis sp. nov., C. (M.) maculovittatus sp. nov., C. (M.) melanochromus sp. nov., C. (M.) platyetrus sp. nov., C. (M.) recavus sp. nov., C. (M.) ruficorpus sp. nov., C. (M.) scirpophagae sp. nov., C. (M.) staurorhytis sp. nov., C. (P.) hirsutus sp. nov., C. (S.) acaretrus sp. nov., and C. (S.) punctulosus sp. nov. are described and illustrated. Also, eleven species are reported as new to China: C. (M.) alticinctus (Tobias, 1989), C. (M.) alveatus (Tobias, 1989), C. (M.) calcaratus (Tobias, 1989), C. (M.) flagellaris (Tobias, 1989), C. (M.) insidiatrix (Tobias, 1989), C. (M.) milkoi (Tobias, 2003), C. (M.) moskovitus (Tobias, 1997), C. (M.) semilunaris (Tobias, 2000), C. (M.) temporalis (Tobias, 1986), C. (M.) varus (Tobias, 2000) and C. (M.) zaitzevi (Tobias, 1972). Four new combinations are proposed: C. (P.) compressor (Chen & Ji, 2003) comb. nov., C. (P.) macrocorpus (Ji & Chen, 2003) comb. nov., C. (P.) polycolor (Chen & Ji, 2003) comb. nov. and C. (Baculonus) rubriventris (Tobias, 1988) comb. nov. The following new names are proposed: C. (M.) jiae nom. nov. for C. (M.) bimaculatus (Chen & Ji, 2003) and C. (M.) substernatus nom. nov. for C. (M.) tobiasi (Yuldashev, 2011). Microchelonus (Carinichelonus) cavifrons Tobias, 2000 is synonymized with C. (Ca.) tabonus Sonan, 1932. A key to the Chinese species of the subgenus Microchelonus is provided together with keys to the currently known species of the subgenera Carinichelonus, Stylochelonus and Parachelonus.

Review of the subgenus Chelonus of the genus Chelonus Panzer (Braconidae: Cheloninae) with description of twenty-one new species from China.

The subgenus Chelonus Panzer, 1806 of genus Chelonus Panzer, 1806 is revised for China and 73 (of which 31 are illustrated) species are recognized. Twenty-one new species, namely, C. (C.) akinakes sp. nov., C. (C.) ameterion sp. nov., C. (C.) angustivertex sp. nov., C. (C.) apicoretusus sp. nov., C. (C.) argoskeles sp. nov., C. (C.) aspros sp. nov., C. (C.) bouommatus sp. nov., C. (C.) brochus sp. nov., C. (C.) columnatus sp. nov., C. (C.) ferrugineus sp. nov., C. (C.) gilvus sp. nov., C. (C.) glomerosus sp. nov., C. (C.) hadrosetron sp. nov., C. (C.) longipectus sp. nov., C. (C.) notochinensis sp. nov., C. (C.) pedinos sp. nov., C. (C.) perspicillatus sp. nov., C. (C.) tanyaisthema sp. nov., C. (C.) transversus sp. nov., C. (C.) truncatus sp. nov. and C. (C.) wuyiensis sp. nov., are described and illustrated. Nine species are recorded from China for the first time, i.e., C. (C.) breviventris Thomson, 1874, C. (C.) capsa Tobias, 1972, C. (C.) cesa Kocak & Kemal, 2013, C. (C.) dauricus Telenga, 1941, C. (C.) fumarius Tobias, 2000, C. (C.) pannonicus Szpligeti, 1896, C. (C.) praepusillus Tobias, 2000, C. (C.) subseticornis Tobias, 1971 and C. (C.) wullii Kittel, 2016. A key to the Chinese species of the subgenus Chelonus Panzer, 1806 is provided.

A review of the subgenera Arichelonus, Megachelonus and Scabrichelonus of the genus Chelonus Panzer (Braconidae: Cheloninae) with description of five new species from China.

The subgenus Arichelonus Viereck, 1913 of genus Chelonus Panzer, 1806 is newly recorded from China and five new species belonging to three different subgenera are described and illustrated from China, i.e., Chelonus (Arichelonus) allokotosus sp. nov., Chelonus (Arichelonus) kenosetrus sp. nov., Chelonus (Megachelonus) irilaminatus sp. nov., Chelonus (Megachelonus) macrodontus sp. nov., and Chelonus (Scabrichelonus) nigrifemoratus sp. nov. Keys to the currently known species of the subgenera Arichelonus, Megachelonus and Scabrichelonus are provided.

Roles of oxidant, activator, and surfactant on enhanced electrokinetic remediation of PAHs historically contaminated soil.

Electrokinetic (EK) remediation technology can enhance the migration of reagents to soil and is especially suitable for in situ remediation of low permeability contaminated soil. Due to the long aging time and strong hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) from historically polluted soil, some enhanced reagents (oxidant, activator, and surfactant) were used to increase the mobility of PAHs, and remove and degrade PAHs in soil. However, under the electrical field, there are few reports on the roles and combined effect of oxidant, activator, and surfactant for remediation of PAHs historically contaminated soil. In the present study, sodium persulfate (PS, oxidant, 100 g L-1) or/and Tween 80 (TW80, surfactant, 50 g L-1) were added to the anolyte, and citric acid chelated iron(II) (CA-Fe(II), activator, 0.10 mol L-1) was added to catholyte to explore the roles and contribution of enhanced reagents and combined effect on PAHs removal in soil. A constant voltage of 20 V was applied and the total experiment duration was 10 days. The results showed that the removal rate of PAHs in each treatment was PS + CA-Fe(II) (21.3%) > PS + TW80 + CA-Fe(II) (19.9%) > PS (17.4%) > PS + TW80 (11.4%) > TW80 (8.1%) > CK (7.5%). The combination of PS and CA-Fe(II) had the highest removal efficiency of PAHs, and CA-Fe(II) in the catholyte could be transported toward anode via electromigration. The addition of TW80 reduced the electroosmotic flow and inhibited the transport of PS from anolyte to the soil, which decreased the removal of PAHs (from 17.4 to 11.4% with PS, from 21.3 to 19.9% with PS+CA-Fe(II)). The calculation of contribution rates showed that PS was the strongest enhancer (3.3~9.9%), followed by CA-Fe(II) (3.9~8.5%) (with PS), and the contribution of TW80 was small and even negative (-1.4~0.6%). The above results indicated that the combined application of oxidant and activator was conducive to the removal of PAHs, while the addition of surfactant reduced the EOF and the migration of oxidant and further reduced the PAHs removal efficiency. The present study will help to further understand the role of enhanced reagents (especially surfactant) during enhanced EK remediation of PAHs historically contaminated soil.

Circ_0060077 Knockdown Alleviates High-Glucose-Induced Cell Apoptosis, Oxidative Stress, Inflammation and Fibrosis in HK-2 Cells via miR-145-5p/VASN Pathway.

The involvement of circular RNAs (circRNAs) in the progression of diabetic nephropathy (DN) has been reported. However, the functions of circ_0060077 in DN remain unclear. HK-2 cells were treated with high glucose (HG) to establish DN cell model. Quantitative real-time polymerase chain reaction (qRT-PCR) was proceeded to determine the levels of circ_0060077, microRNA-145-5p (miR-145-5p) and vasorin (VASN). Cell counting kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay and colony formation assay were conducted to assess cell proliferation ability. Flow cytometry analysis was employed for cell apoptosis. The oxidative stress level was evaluated by commercial kits. Enzyme-linked immunosorbent assay (ELISA) was adopted to examine the concentrations of inflammatory factors. Western blot assay was utilized for protein levels. Dual-luciferase reporter assay and RNA pull-down assay were manipulated to analyze the relationships among circ_0060077, miR-145-5p and VASN. Circ_0060077 level was increased in DN patients and HG-stimulated HK-2 cells. Circ_0060077 knockdown ameliorated the inhibitory effect of HG on HK-2 cell proliferation and the promotional effects on cell apoptosis, oxidative stress, inflammation and fibrosis. MiR-145-5p was identified as the target for circ_0060077 and miR-145-5p inhibition ameliorated the effect of circ_0060077 silencing on HG-induced HK-2 cell injury. Moreover, miR-145-5p directly bound to VASN. Overexpression of miR-145-5p facilitated cell proliferation and repressed apoptosis, oxidative injury, inflammation and fibrosis in HG-induced HK-2 cells by targeting VASN. Circ_0060077 silencing protected HK-2 cells from HG-induced damage by regulating miR-145-5p/VASN axis.

A new subgenus of Chelonus Panzer, 1806 (Braconidae: Cheloninae) from China.

A new subgenus of the genus Chelonus Panzer, 1806 (Braconidae: Cheloninae), Mirachelonus subgen. nov. (type species: Chelonus (Mirachelonus) miraventris sp. nov.) with deeply incurved apex of carapace, is described and illustrated from southwest China. A key to the subgenera currently recognized in Chelonus is included to facilitate future identifications.

The mitochondrial genome of Chelonus formosanus (Hymenoptera: Braconidae) with novel gene orders and phylogenetic implications.

Chelonus formosanus Sonan is an important egg-larval parasitoid of noctuid moths and a potential candidate for understanding interactions between host and parasitoid mediated by polydnavirues (PDVs). We sequenced and annotated the mitochondrial genome of C. formosanus, which is 15,466 bp in length and possesses 38 mitochondrial genes. However, unlike most animal mitochondrial genomes, it contains one extra trnF gene. There are five transfer RNA (tRNA) rearrangement events compared with the ancestral gene order, which is a novel rearrangement type in Hymenoptera for all published mitogenomes so far. Phylogenetic trees supported C. formosanus from the subfamily Cheloninae was closely related to the subfamily Cardiochilinae and Microgastrinae.

Evaluation on blood coagulation and C-reactive protein level among children with mycoplasma pneumoniae pneumonia by different chest imaging findings.

ABSTRACT: Mycoplasma pneumoniae infection may induce a systemic hypercoagulable abnormality, like organ embolism and infarction. Indexes of blood coagulation and C-reactive protein (CRP) have been reported different between healthy people and mycoplasma pneumoniae pneumonia (MPP) patients, but this difference in MPP patients with different chest imaging findings has rarely been reported.We performed a retrospective study of 101 children with MPP and 119 controls, combined with radiological examination and blood tests, to compare the blood coagulation and CRP level among MPP children with different chest imaging findings.For the MPP children with different chest imaging findings, there were significant differences in CRP, fibrinogen (FIB) and D-dimer (D-D) levels among subgroups (P = .004, P = .008 and P < .001 respectively). The CRP level in group of interstitial pneumonia was significantly higher than that in groups of bronchopneumonia and hilar shadow thickening (P = .003 and P = .001 respectively). And the FIB and D-D values in group of lung consolidation were significantly higher than that in the other 3 groups (all P < .05). When compared with controls, the white blood cell, CRP, FIB, and D-D levels in MPP children were significantly higher, and the activated partial thromboplastin time and thrombin time levels were significantly lower (all P < .05).Our results showed that CRP level changed most significantly in group of interstitial pneumonia, whereas FIB, D-D levels changed most significantly in the lung consolidation group.

Separation and characterization of impurities and isomers in cefpirome sulfate by liquid chromatography/tandem mass spectrometry and a summary of the fragmentation pathways of oxime-type cephalosporins.

RATIONALE: Although the identification of degradation products of cefpirome sulfate has been reported, there has been no report concerning the impurities in bulk samples of this compound. To meet the requirements of the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use, the structures of impurities whose content are over 0.1% need to be confirmed. Thus, characterization of the impurities in cefpirome sulfate bulk samples is critical for controlling the production of this drug. METHODS: The structures of cefpirome sulfate impurities were investigated using two-dimensional liquid chromatography (LC) coupled to electrospray ionization tandem mass spectrometry. In the first LC dimension, a Kromasil 100-5C18 column (4.6 mm × 250 mm, 5 µm) was used, and the mobile phases were 0.03 M ammonium dihydrogen phosphate solution and acetonitrile. In the second dimension, the column was a Shimadzu Shim-pack GISS C18 column (50 mm × 2.1 mm, 1.9 µm), and the mobile phases were 10 mM ammonium formate solution and methanol. An ion trap time-of-flight mass spectrometer operated in both positive and negative ion mode was employed in this study. RESULTS: Nine impurities and isomers in cefpirome sulfate, eight of which were previously unknown, were separated and characterized. Structures were proposed for the eight unknown compounds based on the MSn fragmentation data. The degradation behavior of cefpirome sulfate was also studied. CONCLUSIONS: Based on the characterization of impurities and isomers, this study could be used to improve the quality control of the cefpirome sulfate drug recommended in pharmacopoeias. The degradation behavior of cefpirome sulfate provides a basis for the selection of storage conditions.

Occurrence and risk assessment of steroid estrogens in environmental water samples: A five-year worldwide perspective.

The ubiquitous occurrence of steroid estrogens (SEs) in the aquatic environment has raised global concern for their potential environmental impacts. This paper extensively compiled and reviewed the available occurrence data of SEs, namely estrone (E1), 17α-estradiol (17α-E2), 17ß-estradiol (17ß-E2), estriol (E3), and 17α-ethinyl estradiol (EE2), based on 145 published articles in different regions all over the world including 51 countries and regions during January 2015-March 2020. The data regarding SEs concentrations and estimated 17ß-estradiol equivalency (EEQ) values are then compared and analyzed in different environmental matrices, including natural water body, drinking and tap water, and wastewater treatment plants (WWTPs) effluent. The detection frequencies of E1, 17ß-E2, and E3 between the ranges of 53%-83% in natural water and WWTPs effluent, and the concentration of SEs varied considerably in different countries and regions. The applicability for EEQ estimation via multiplying relative effect potency (REPi) by chemical analytical data, as well as correlation between EEQbio and EEQcal was also discussed. The risk quotient (RQ) values were on the descending order of EE2 > 17ß-E2 > E1 > 17α-E2 > E3 in the great majority of investigations. Furthermore, E1, 17ß-E2, and EE2 exhibited high or medium risks in water environmental samples via optimized risk quotient (RQf) approach at the continental-scale. This overview provides the latest insights on the global occurrence and ecological impacts of SEs and may act as a supportive tool for future SEs investigation and monitoring.

Study of the impurity profile and characteristic fragmentation of Δ3 -isomers in cephapirin sodium using dual liquid chromatography coupled with ion trap/time-of-flight mass spectrometry.

RATIONALE: According to the requirements of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH), the structures of impurities in pharmaceutical products present at over 0.1% need to be confirmed. Therefore, the aim of this study is to separate and identify the impurities in cephapirin sodium drug substances, so as to guide the industry to improve the production process and storage conditions and reduce the amount of impurities in the product. METHODS: In the first chromatography dimension, a Boston Green ODS (4.6 mm × 250 mm, 5 µm) column was used, with a mobile phase composed of 0.05 M sodium dihydrogen phosphate aqueous solution and acetonitrile. In the second dimension, the column was a Shimadzu Shim-pack GISS C18 (50 mm × 2.1 mm, 1.9 µm), using 10 mM ammonium formate solution and methanol as the mobile phase. RESULTS: The fragmentation behavior of cephapirin and its impurities and isomers was studied and the structures of impurities were deduced based on the MSn data. For six unknown impurities tentative structures were proposed. The degradation behavior of cephapirin sodium was also studied. Impurities 1 to 11 were found in commercial cephapirin sodium samples, indicating that cephapirin sodium should be stored in closed containers. CONCLUSIONS: The contradiction between the non-volatile mobile phase and mass spectrometry was solved by means of multiple heart-cutting approaches and an on-line desalting technique. Twelve impurities and isomers were separated and characterized. These results could be used to improve the methods described in pharmacopoeias for the quality control of cephapirin sodium.

Characterization of four unknown impurities in azithromycin and erythromycin imino ether using two-dimensional liquid chromatography coupled to high-resolution quadrupole time-of-flight mass spectrometry and nuclear magnetic resonance.

RATIONALE: A simple and sensitive method was developed for the separation and characterization of four unknown impurities in azithromycin and erythromycin imino ether using two-dimensional liquid chromatography coupled to high-resolution quadrupole time-of-flight mass spectrometry (2D LC/QTOFMS) with positive and negative electrospray ionization. METHODS: The chromatographic separation in the first dimension was performed with a Waters Xbridge RP18 column in gradient mode using binary mobile phase: (A) phosphate buffer (pH 8.2)-acetonitrile (47:53, v/v) and (B) water-acetonitrile (90:10, v/v). In the second dimension, the chromatographic separation was performed using a Shimadzu Shim-pack GISS C18 column with volatile mobile phases: (A) ammonium formate solution (10 mM) and (B) methanol. RESULTS: The molecular formulae and structures of the four impurities were deduced based on the LC/MS/MS data, and further confirmed using 1 H NMR, 13 C NMR, 1 H-1 H COSY, HSQC and HMBC NMR spectra after semi-preparative isolation of impurities. In addition, the mechanism for the formation of the impurities was also proposed. CONCLUSIONS: The contradiction between the non-volatile salt mobile phase and mass spectrometry was solved by means of a multiple heart-cutting 2D LC approach and on-line desalination technology. Four impurities were separated and characterized. These results could further improve the method of official monographs in pharmacopoeias and guides to improve the process of reducing impurity content.

Characterization of two unknown impurities in roxithromycin by 2D LC-QTOF/MS/MS and NMR.

Two unknown impurities in roxithromycin were discovered and preliminarily characterized by two-dimensional liquid chromatography coupled with QTOF mass analyzer (2D LC-QTOF MS/MS). The column-switching technique of 2D LC made the chromatographic conditions in official standard of roxithromycin compatible with mass spectrometric detector. The complete MS/MS fragmentation patterns of the impurities were studied to obtain structural information of these impurities. Furthermore, these two impurities were separated and purified by preparative HPLC, and their structures were confirmed by 1D and 2D nuclear magnetic resonance (NMR). Structural elucidation of two impurities by 1H NMR, 13C NMR, the 1H-1H COSY, HSQC and HMBC NMR spectra has been discussed. Based on high resolution MS/MS and NMR data, the structures of these two impurities were elucidated respectively as 11-O-[(2-Methoxyethoxy) methyl] roxithromycin and de(N-methyl)-N-formyl roxithromycin. In addition, the mechanisms for formation of the impurities were also proposed.

Fast photocatalytic inactivation of Microcystis aeruginosa by metal-organic frameworks under visible light.

In this work, Metal-organic Frameworks (MOFs) were applied to inactivate algae under visible light with low doses. Five MOFs with different compositions (Zn and Fe; carboxylates or imidazolates) were successfully synthesized and characterized by XRD, SEM and UV-vis. The effects of MOFs on Microcystis aeruginosa were evaluated with regard to morphology characteristics, physiological activity, cell integrity and pigment degradation. The results indicated that Ag/AgCl@ZIF-8 outperformed MOF-235, ZIF-8, Bi2WO6/MIL-100(Fe) and BiOBr/MOF-5 in the degradation of chlorophyll a at the dose of 10 mg L-1. After 6 h of irradiation, 93.1% of Microcystis aeruginosa died and was unable to regrow and reproduce, which was demonstrated by changes in cell morphology, damage of cell membrane integrity and antioxidant enzyme system. Besides, the intracellular organic matter (IOM) and extracellular organic matter (EOM) were proven to be efficiently removed by MOF-assisted photocatalytic inactivation. Superoxide radical (O2·-) was demonstrated to be the major reactive oxygen species. A probable mechanism was proposed that the electrons in the valence band of Ag/AgCl@ZIF-8 transfer into the conduction band under irradiation to produce O2·- which inactivated the algae cells. Furthermore, Ag/AgCl@ZIF-8 can effectively remove Microcystis aeruginosa under sunlight and is of great application prospects for algae removal in real water bodies.

Study of the impurity profile and polymerized impurity in mezlocillin sodium by multiple heart-cutting two-dimensional liquid chromatography coupled with ion trap time-of-flight mass spectrometry.

RATIONALE: Eleven impurities and one polymerized impurity in mezlocillin were identified and their formation mechanisms were investigated in this study. The sources and reasons for the formation of impurities were revealed, which may guide industry to improve the manufacturing process and storage conditions and reduce the content of impurities in products. The results from this study also provided a scientific basis for the improvement of official monographs in pharmacopoeias. METHODS: The impurity profiles and polymerized impurity in mezlocillin were studied by multiple heart-cutting two-dimensional liquid chromatography coupled with ion trap time-of-flight mass spectrometry (2D-LC/IT-TOF MS) in both positive and negative modes of electrospray ionization. Target eluents from the first dimensional chromatography with a non-volatile mobile phase were trapped and sent to the second dimensional chromatography with a volatile mobile phase by a switching valve. The structures of the impurities in the mezlocillin drug substance were deduced based on the high-resolution MSn data. RESULTS: In the environment of water, oxygen, high temperature, acid and base, a series of degradation products could be easily produced from mezlocillin. Mezlocillin was hydrolyzed into impurities I, IV, V and X, and was degraded into impurity III by methanolysis. Mezlocillin was oxidized into sulfoxide by producing impurity XI. Furthermore, impurities VI, VII, VII and IX were all isomers of mezlocillin. The proposed formation pathways of these products were demonstrated in this study. CONCLUSIONS: Eleven degradation impurities and one polymerized impurity in mezlocillin were separated and characterized. Based on characterization of impurities, this study discovered the mechanism of impurity production and provided guidance for manufacturers to improve the process and storage conditions and reduce levels of impurities.

Organo-Catalyzed Regio- and Geometry-Specific Construction of ß-Hydroxyl-α-vinyl Carboxylic Esters: Substrate Scope, Mechanistic Insights, and Applications.

A green protocol has been developed for the synthesis of ß-hydroxyl-α-vinyl carboxylic esters using aldehydes and α,ß-unsaturated esters bearing an activated γ proton as starting materials under Morita-Baylis-Hillman (MBH) reaction conditions. Diverse ß-hydroxyl-α-vinyl carboxylic esters have been synthesized regiospecifically in moderate to good yields with only E geometric selectivity. Other remarkable features include atom efficiency, environmental benignancy, and mild reaction conditions. Furthermore, the reaction products could be readily converted into tetrahydrofuran, dihydrofuran, and furan derivatives.

Growth inhibition of Microcystic aeruginosa by metal-organic frameworks: effect of variety, metal ion and organic ligand.

Metal-organic frameworks (MOFs), as a new type of nanomaterial, have been rapidly developed and widely applied in the environmental area. However, the algae removal efficiency of MOFs, the effect of metal ions and organic ligands contained in MOFs and the stability of MOFs in water need further study. Based on the characteristics of algae, five types of MOFs, which were Cu-MOF-74, Zn-MOF-74, ZIF-8, Ag/AgCl@ZIF-8 and MIL-125(Ti) were synthesized and characterized by X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), and X-ray photoelectron spectroscopy (XPS). The effect of MOFs on the growth of Microcystis aeruginosa was comparatively studied, and the inhibition mechanism of MOFs on algae as well as the stability of MOFs was explored. Results showed that all of the as-synthetic MOFs had superior stability in water, and the order of stability of MOFs followed the order MIL-125(Ti) > Cu-MOF-74 > Ag/AgCl@ZIF-8 > ZIF-8 > Zn-MOF-74. The types of metal ions and organic ligands doped in MOFs have grade affected the inhibitory efficiency on the algae: containing Cu2+ and Ag+ ions, MOFs had more significant inhibitory capacity to algae than those containing Zn2+ ions; meanwhile, compared with MOFs which are assembled with 2,5-dihydroxyterephthalic acid (DHTA) organic ligands, MOFs containing 2-methylimidazole (GC) organic contributed to the removal of algae significantly. The order of inhibitory effects of algae by five MOFs follows the order Cu-MOF-74 > Ag/AgCl@ZIF-8 > ZIF-8 > Zn-MOF-74 > MIL-125(Ti). The physiological characteristics of algal cells were changed after being treated with different concentrations of Cu-MOF-74. Once the concentration of Cu-MOF-74 reached 1 mg L-1, the algal cells began to be inhibited, the relative inhibition rate of algal cells at 120 h was over 400%, and the inhibition process fitted pseudo-second-order kinetic model well. The Cu2+ released by Cu-MOF-74 that the concentration higher than 1 mg L-1 would lead to the destruction of algae cell morphology and the loss of cell integrity, causing cell contents to be partially released into the water, promoting the accumulation and precipitation of algal cells which were destabilizing already to achieve the purpose of inhibition of algae. In summary, MOFs can be used to inhibit the growth of cyanobacteria and have a promising application prospect.