Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 44
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Br J Clin Pharmacol ; 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38926090

RESUMO

AIMS: The reference nutrient intake for vitamin D in people aged ≥4 years is 10 µg/day (400 IU/day) in the UK, but the recommended daily allowance is 15 µg/day (600 IU/day) for people aged 1-70 years in the USA. Here, we aim to compare the 25-hydroxyvitamin D (25(OH)D) serum concentration profiles between the 2 doses. METHODS: With world-wide trial data of adults aged ≥18 years, 45-93 kg, we constructed a minimal physiologically based pharmacokinetics model of serum concentrations of vitamin D and 25(OH)D using nonlinear mixed effects modelling. We used this model to forecast the mean, 2.5th and 97.5th percentiles for serum 25(OH)D concentrations in British adults aged ≥16 years. RESULTS: Our final model used bodyweight to adjust volume of each compartment and maximum clearance of 25(OH)D. No other covariate was identified. The model accurately predicted independent data from trials of a broad range of dosing regimens. We simulated British adults and showed that circulating 25(OH)D concentrations in 95% of people taking 10 µg/day for a year is predicted to reach 50 nmol/L in 32 weeks, while 97.5% of those on 15 µg/day were predicted to attain this threshold within 28 weeks. CONCLUSION: Both doses are efficacious in >95% of the British population. The daily dose of 15 µg can help 97.5% of the British adults achieve 50 nmol/L serum 25(OH)D and reach the 25 nmol/L threshold in 4 weeks.

2.
Phytochemistry ; 223: 114119, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38705266

RESUMO

Six previously undescribed prenylated indole diketopiperazine alkaloids, talaromyines A-F (1-6), were isolated from the marine-derived fungus Talaromyces purpureogenus SCSIO 41517. Their structures including absolute configurations were elucidated on the basis of comprehensive spectroscopic data including NMR, HR-ESI-MS, and electronic circular dichroism calculations, together with chemical analysis of hydrolysates. Compounds 1-5 represent the first example of spirocyclic indole diketopiperazines biosynthesized from the condensation of L-tryptophan and L-alanine. Compounds 2 and 4-5 showed selective inhibitory activities against phosphatases TCPTP and MEG2 with IC50 value of 17.9-29.7 µM, respectively. Compounds 4-5 exhibited mild cytotoxic activities against two human cancer cell lines H1975 and HepG-2.


Assuntos
Dicetopiperazinas , Talaromyces , Talaromyces/química , Dicetopiperazinas/química , Dicetopiperazinas/farmacologia , Dicetopiperazinas/isolamento & purificação , Humanos , Estrutura Molecular , Prenilação , Ensaios de Seleção de Medicamentos Antitumorais , Relação Estrutura-Atividade , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Alcaloides Indólicos/isolamento & purificação , Alcaloides Indólicos/química , Alcaloides Indólicos/farmacologia , Alcaloides/química , Alcaloides/farmacologia , Alcaloides/isolamento & purificação , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Células Hep G2 , Proliferação de Células/efeitos dos fármacos , Monoéster Fosfórico Hidrolases/antagonistas & inibidores , Monoéster Fosfórico Hidrolases/metabolismo , Linhagem Celular Tumoral
3.
J Agric Food Chem ; 72(12): 6402-6413, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38491989

RESUMO

Bacterial diseases could severely harm agricultural production. To develop new antibacterial agents, the secondary metabolites of a deep-sea-derived fungus Simplicillium obclavatum EIODSF 020 with antibacterial activities against plant and fish pathogens were investigated by a bioassay-guided approach, which led to the isolation of 11 new peptaibiotics, simplicpeptaibs A-K (1-11). They contain 16-19 residues, including ß-alanine, tyrosine, or tyrosine O-sulfate, that were rarely present in peptaibiotics. Their structures were elucidated by spectroscopic analyses (NMR, HRMS, HRMS2, and ECD) and Marfey's method. The primary and secondary structures of novel sulfated peptaibiotic 9 were reconfirmed by single-crystal X-ray diffraction analysis. Genome sequencing of S. obclavatum EIODSF 020 allowed the detection of a gene cluster encoding two individual NRPSs (totally containing 19 modules) that was closely related to simplicpeptaib biosynthesis. Antibacterial investigations of 1-11 together with the previously isolated linear and cyclic peptides from this strain suggested the antibacterial property of this fungus was attributed to the peptaibiotics and cyclic lipopeptides. Among them, compounds 4, 6, 7, and 9 showed significant activity against the tobacco pathogen Ralstonia solanacearum or tilapia pathogens Streptococcus iniae and Streptococcus agalactiae. The antibacterial activity of 6 against R. solanacearum could be enhanced by the addition of 1% NaCl. The structure-bioactivity relationship of simplicpeptaibs was discussed.


Assuntos
Antibacterianos , Hypocreales , Animais , Antibacterianos/química , Hypocreales/metabolismo , Peptídeos Cíclicos/metabolismo , Peixes/metabolismo
5.
Sci Total Environ ; 898: 165583, 2023 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-37467984

RESUMO

As key components of intermediate-volatility organic compounds (IVOCs), intermediate-volatility aromatic hydrocarbons (IAHs) are important precursors of ozone and secondary organic aerosol (SOA). Rubber products (RP) industry has significant influence on ozone and SOA formation, yet few studies are available to characterize their emissions of IAHs. Here we conducted measurements of IAHs emitted from rubber products (RP) factories in China. Tens of C10-C12 IAH species were identified with C10H14-AH (such as tetramethyl benzene) and naphthalene (C10H8) as the dominant species, accounting for 57.0 % - 100.0 % of total IAHs emissions. On average, IAHs showed higher concentrations (1.1 × 102-1.2 × 103 µg m-3) in mixing, extrusion, painting, crushing, and grinding processes than those (8.2-14 µg m-3) in vulcanization and gumming processes as well as warehouse. Moreover, IAHs concentrations were 1.3-1.7 times of volatile aromatic hydrocarbons (VAHs; C6-C9 aromatics) in the emissions from mixing, extrusion, crushing and grinding processes. The average IAHs to volatile organic compounds (VOCs) ratios also showed relatively higher values (0.1-0.7) in these processes, which were significantly higher than those of 0.01-0.03 observed in other industries, and even comparable to the IVOCs to VOCs ratio of 0.2 used for estimating solvent-related emission. The ozone and SOA formation potential values of IAHs were 1.1-2.6 times and 0.9-3.9 times those of VAHs, respectively, and were 0.5-1.0 times and 0.9-1.9 times those of total VOCs in emissions of mixing, extrusion, crushing, and grinding processes of the RP industry. The total emission of IAHs was estimated to be 115.8 Gg from the RP industry in China, which could account for 64.5 % of total IAH emissions from all industrial sectors. This study further suggests that the RP industry might be an important emission source of IAHs with substantially higher ozone and SOA formation potentials.

6.
Phytochemistry ; 205: 113511, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36372238

RESUMO

Seven undescribed polyhydroxylated mycoecdysteroids, punicesterones A-G, along with two known analogues, were isolated from the deep-sea-derived fungal strain Aspergillus puniceus SCSIO z021 (Trichocomaceae). Their structures with absolute configurations were elucidated by a combination of extensive NMR spectroscopic analysis, HRESIMS data, and single-crystal X-ray diffraction experiments. Punicesterone An unexpectedly possessed a nicotinoyl unit substituted at C-22 of a typical ecdysteroid skeleton. All of the isolated compounds were evaluated for their anti-inflammatory, lipid-lowering, and antibacterial activities. Punicesterones B and C showed the activity of reducing triglyceride in 3T3-L1 adipocytes in a dosage-dependent manner, and also exhibited antibacterial activity against five pathogens.


Assuntos
Aspergillus , Fungos , Aspergillus/química , Antibacterianos/química , Estrutura Molecular
7.
Contrast Media Mol Imaging ; 2022: 6283372, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36110982

RESUMO

In order to investigate the correlation between neuroaxon-guiding factor (Netrin-1), deleted in colorectal cancer (DCC), uncoordinated 5B (UNC5B), and vascular endothelial growth factor (VEGF) expression machine in villus tissues of delayed abortion in colorectal cancer, a total of 120 pregnant women are selected from February 2019 to August 2021. The two groups of subjects improve the relevant examinations before surgery and the underwent negative pressure induces abortion hysterectomy guided by abdominal ultrasound under intravenous anesthesia. The mRNA and protein expressions of netrin-1, DCC, UNC5B, and VEGF in the villi of the two groups are detected by real-time fluorescence quantitative polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC), and the correlation of the four indicators is analyzed by Pearson's test.


Assuntos
Neoplasias Colorretais , Fator A de Crescimento do Endotélio Vascular , Receptor DCC , Feminino , Humanos , Fatores de Crescimento Neural/genética , Fatores de Crescimento Neural/metabolismo , Receptores de Netrina , Netrina-1 , Gravidez , RNA Mensageiro , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo
8.
Spectrochim Acta A Mol Biomol Spectrosc ; 278: 121341, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-35550993

RESUMO

Here, we report a novel aptasensor based on decahedral silver nanoparticles (Ag10NPs) enhanced fluorescence polarization (FP) for detecting PCB-77. Using aptamer modified Ag10NPs hybridized with DNA sequence labeled fluorescent group as an analytical probe, polychlorinated biphenyls (PCB-77) could be detected with high sensitivity and selectivity. The linear range of determination was 0.02 ng/L to 390 ng/L and the limit of detection was 5 pg/L. In addition, through the optimization of the experiment condition and signal probe DNA (pDNA), we found that the maximum FP signal could be generated when the distance between fluorescein and the surface of Ag10NPs was 3 nm. When the aptamer was immobilized on the surface of Ag10NPs could be strengthened the anti-interference performance of aptamer nanoprobe and further improved the detection ability. At the same time, we also compared the detection performance of the traditional FP signal enhancer streptavidin (SA) analysis system. The fluorescence polarization aptasensor could detect PCB-77 samples efficiently in complex environmental water, which shows a good application prospect.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Nanopartículas Metálicas , Bifenilos Policlorados , Técnicas Biossensoriais/métodos , Polarização de Fluorescência/métodos , Corantes Fluorescentes , Limite de Detecção , Prata
9.
Huan Jing Ke Xue ; 43(1): 150-159, 2022 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-34989499

RESUMO

A large number of volatile organic compounds (VOCs) are emitted from the high temperature treatment process in the dismantling and recycling procedure of e-wastes, which has a significant impact on the surrounding environment and human health. In this study, an e-waste dismantling and recycling yard was selected to measure the VOCs concentrations and compositions in the exhaust of treatment facilities of heating baking board, plastic granulation, wet extraction, and pyrometallurgical workshops, and the emission characteristics of VOCs and emission factors for total VOCs from different production processes were investigated. The results showed that there were significant differences in total VOCs emission concentrations among different production processes. The concentrations of total VOCs produced in different workshops followed the descending order of the heating baking board (heating rotary plate furnace) process[(2096.1±732.4) µg·m-3] > plastic granulation process[(1639.1±538.5) µg·m-3] > heating baking board (electric heater) process[(625.3±535.5) µg·m-3] > pyrometallurgical process[(436.8±305.2) µg·m-3] > wet extraction process[(271.3±73.1) µg·m-3]. The compositions of VOCs emitted from different production processes were also clearly different; however, the major components of VOCs were generally oxygenated compounds and aromatic hydrocarbons. The specific component characteristics were as follows:the dominant groups of VOCs emitted from the heating baking board process (including heating rotary plate furnaces and electric heaters) were oxygenated compounds and aromatic hydrocarbons, accounting for 74.1%-79.7% of the total. The main components of VOCs emitted from the pelletizing process were aromatic hydrocarbons and oxygenated compounds, accounting for 71.8% of the total. Oxygenated compounds and aromatic hydrocarbons, which contributed equally, were also the main groups of VOCs discharged by the wet extraction process, and the sum proportion of the two groups was 84.2%. Halogenated hydrocarbon was the dominant group of VOCs from the pyrometallurgical process, accounting for 92.1% of the sum of VOCs. There was a substantial divergence in the total VOCs emission factors of different production processes. The ranking of the mean values of emission factors of total VOCs was as follows:the heating baking board (electric heater) process (297.0 g·t-1) > plastic granulation process (29.5 g·t-1) > wet extraction process (25.4 g·t-1) > heating baking board (heating rotary plate furnace) process (25.2 g·t-1) > pyrometallurgical process (1.9 g·t-1). Therefore, the main VOCs emission processes of the e-waste centralized dismantling and recycling industry were the heating baking board process and plastic granulation process.


Assuntos
Poluentes Atmosféricos , Resíduo Eletrônico , Compostos Orgânicos Voláteis , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Humanos , Plásticos , Reciclagem , Compostos Orgânicos Voláteis/análise
10.
J Nat Prod ; 84(10): 2727-2737, 2021 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-34596414

RESUMO

Nine new highly oxygenated 3,5-dimethylorsellinic acid-derived meroterpenoids, talaromynoids A-I (1-9), were isolated from the marine-derived fungus Talaromyces purpureogenus SCSIO 41517. Their structures including absolute configurations were elucidated by HRMS, NMR, single-crystal X-ray diffraction analysis, and electronic circular dichroism calculations. Compounds 1 and 7-9 possessed unprecedented 5/7/6/5/6/6, 6/7/6/6/6/5, 6/7/6/5/6/5/4, and 7/6/5/6/5/4 polycyclic systems, respectively. Biologically, compound 5 showed selective inhibitory activity against phosphatase CDC25B with an IC50 value of 13 µM. Moreover, 7-9 and 12 exhibited the activity of reducing triglyceride in 3T3-L1 adipocytes in a dosage-dependent manner.


Assuntos
Metabolismo dos Lipídeos/efeitos dos fármacos , Talaromyces/química , Terpenos/farmacologia , Células 3T3-L1 , Animais , Organismos Aquáticos/química , China , Humanos , Camundongos , Estrutura Molecular , Oxigênio , Terpenos/isolamento & purificação , Triglicerídeos/metabolismo , Fosfatases cdc25/antagonistas & inibidores
11.
J Org Chem ; 86(18): 12831-12839, 2021 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-34477382

RESUMO

(+)- and (-)-talaromyoxaones A and B (1 and 2, respectively), two new oxaphenalenone derivatives with a hemiacetal frame and an unprecedented spirolactone frame of a 2'H,3H,4'H-spiro[isobenzofuran-1,3'-pyran]-3-one unit that show biosynthetic enantiodivergence, and two new oxaphenalenone analogues (±)-11-apopyrenulin (3) and (+)- or (-)-abeopyrenulin (4) were isolated from the marine-derived fungus Talaromyces purpureogenus SCSIO 41517. Their structures were elucidated by spectroscopic analysis, single-crystal X-ray diffraction, and quantum chemical calculations of ECD spectra. Compounds 1 and 2 showed selective inhibitory activity against phosphatases SHP1, SHP2, and MEG2 with IC50 values of 1.3-3.4 µM, and the potential modes of action for 1 were investigated by a preliminary molecular docking study.


Assuntos
Talaromyces , Simulação de Acoplamento Molecular , Monoéster Fosfórico Hidrolases , Espironolactona
12.
CPT Pharmacometrics Syst Pharmacol ; 10(7): 723-734, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33960722

RESUMO

Plasma concentration of vitamin D3 metabolite 25-hydroxyvitamin D3 (25(OH)D3 ) is variable among individuals. The objective of this study is to establish an accurate model for 25(OH)D3 pharmacokinetics (PKs) to support selection of a suitable dose regimen for an individual. We collated vitamin D3 and 25(OH)D3 plasma PK data from reported clinical trials and developed a physiologically-based pharmacokinetic (PBPK) model to appropriately recapitulate training data. Model predictions were then qualified with 25(OH)D3 plasma PKs under vitamin D3 and 25(OH)D3 dose regimens distinct from training data. From data exploration, we observed the increase in plasma 25(OH)D3 after repeated dosing was negatively correlated with 25(OH)D3 baseline levels. Our final model included a first-order vitamin D3 absorption, a first-order vitamin D3 metabolism, and a nonlinear 25(OH)D3 elimination function. This structure explained the apparent paradox. Remarkably, the model accurately predicted plasma 25(OH)D3 following repeated dosing up to 1250 µg/d in the test set. It also made sensible predictions for large single vitamin D3 doses up to 50,000 µg in the test set. Model predicts 10 µg/d regimen may be ineffective for achieving sufficiency (plasma 25(OH)D3 ≥ 75 nmol/L) for a severely deficient individual (baseline 25(OH)D3 = 10 nmol/L), and it might take the same person over 200 days to reach sufficiency at 20 µg/d dose. We propose to personalize vitamin D3 supplementation protocol with this PBPK model. It would require measuring 25(OH)D3 baseline levels, which is not routinely performed under the current UK public health advice. STUDY HIGHLIGHTS: WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC? Vitamin D PK exhibits substantial inter-individual variability. Different officially recommended daily doses are confusing. ​ WHAT QUESTION DID THIS STUDY ADDRESS? Is the UK's recommended 10 µg daily dose sufficient? Should everyone be given same dose? ​ WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE? Our model accurately predicts plasma 25(OH)D under daily oral administration of vitamin D3 . The 10 µg daily vitamin D3 dose is insufficient for prophylaxis (plasma 25(OH)D at 75 nmol/L). ​ HOW MIGHT THIS CHANGE DRUG DISCOVERY, DEVELOPMENT, AND/OR THERAPEUTICS? Combining blood test to measure 25(OH)D baseline with this PBPK model will help inform dosage selection and select follow-up date to improve effectiveness of Hypovitaminosis D treatment.


Assuntos
Calcifediol/farmacocinética , Modelos Biológicos , Vitaminas/farmacocinética , Calcifediol/administração & dosagem , Relação Dose-Resposta a Droga , Humanos , Medicina de Precisão , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Tempo , Vitaminas/administração & dosagem
13.
Sci Rep ; 11(1): 10348, 2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-33990647

RESUMO

A mathematical model based on heat and mass transfer processes in the porous wick of electronic cigarettes was established to describe the atomization of e-liquids according to max liquid temperature, vaporization rate and thermal efficiency in a single puff. Dominant capillary-evaporation effects were defined in the model to account for the effects of electrical power, e-liquid composition and porosity of the wick material on atomization and energy transmission processes. Liquid temperature, vaporization rate, and thermal efficiency were predicted using the mathematical model in 64 groups, varying with electrical power, e-liquid composition and wick porosity. Experimental studies were carried out using a scaled-model test bench to validate the model's prediction. A higher PG/VG ratio in the e-liquid promoted energy transfer for vaporization, and the e-liquid temperature was comparatively reduced at a relatively high power, which was helpful to avoid atomizer overheating. Compared with the other factors, wick porosity affected the thermal efficiency more significantly. The vaporization rate increased with a higher wick porosity in a certain range. The modelling results suggested that a greater wick porosity and a higher PG ratio in e-liquids helped to improve the overall thermal efficiency.

14.
Bioorg Chem ; 107: 104571, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33373758

RESUMO

Nine new xanthone-type and anthraquinone-type mycotoxins including austocystins J-N (1-5), 7-chloro versicolorin A (6), 3'-hydroxy-8-O-methyl versicolorin B (7), 8-O-methyl versiconol (8) and 2',3'-dihydroxy versiconol (9), together with 17 known analogues (10-26) were isolated from an extract of the deep-sea-derived fungus Aspergillus puniceus SCSIO z021. Their structures were elucidated by detailed analysis of spectroscopic data, and their absolute configurations were further determined by quantum chemical calculations of ECD spectra or comparison of the experimental ECD spectra. Eleven hydrogenated austocystins were synthesized from 1-2, 10-15 and 17 by catalytic hydrogenation for bioactivities evaluation. Totally, 18 of the all 37 compounds showed strong toxicity against brine shrimps or Vero cell, and the toxicity of 8-O-methyldemethylsterigmatocystin (18) (LC50 = 0.020 µM) against brine shrimps was higher than those of three positive controls. In addition, 22 of the isolated compounds also exhibited significant inhibitory activity against seven different protein tyrosine phosphatases (PTPs), among them austocystin H (15) and methyl-averantin (24) were the most potent inhibitors with IC50 values of 0.20-3.0 µM. Their structure-bioactivity relationship was also discussed.


Assuntos
Aspergillus/metabolismo , Micotoxinas/química , Proteínas Tirosina Fosfatases/antagonistas & inibidores , Água do Mar/microbiologia , Animais , Artemia/crescimento & desenvolvimento , Aspergillus/isolamento & purificação , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops , Dicroísmo Circular , Conformação Molecular , Micotoxinas/metabolismo , Micotoxinas/farmacologia , Óvulo/efeitos dos fármacos , Óvulo/crescimento & desenvolvimento , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/metabolismo , Proteínas Tirosina Fosfatases/metabolismo , Relação Estrutura-Atividade , Células Vero
15.
Nat Prod Res ; 35(5): 822-825, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30961365

RESUMO

As a medicinal plant, Artemisia annua is widely distributed in China. The purpose of this work was to analyze the chemical composition of essential oil from A. annua aerial portions, as well as to assess its repellent activity against Lasioderma serricorne and Tribolium castaneum adults. GC-FID and GC-MS analyses enabled the identification of 15 components representing 90.1% of the essential oil. The main components included artemisia ketone (70.6%), α-caryophyllene (5.1%) and germacrene D (3.8%). The essential oil was found to possess considerable ability to repel the two storage pests. This paper provided some evidence for the exploitation and utilization of A. annua resources as a natural repellent.


Assuntos
Artemisia annua/química , Besouros/efeitos dos fármacos , Repelentes de Insetos/farmacologia , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Controle Biológico de Vetores , Componentes Aéreos da Planta/química , Tribolium/efeitos dos fármacos , Animais , China , Cromatografia Gasosa-Espectrometria de Massas , Repelentes de Insetos/química , Inseticidas/química , Inseticidas/farmacologia , Monoterpenos/farmacologia
16.
J Environ Sci (China) ; 95: 33-42, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653190

RESUMO

Vertical profiles of isoprene and monoterpenes were measured by a proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS) at heights of 3, 15, 32, 64, and 102 m above the ground on the Institute of Atmospheric Physics (IAP) tower in central Beijing during the winter of 2016 and the summer of 2017. Isoprene mixing ratios were larger in summer due to much stronger local emissions whereas monoterpenes were lower in summer due largely to their consumption by much higher levels of ozone. Isoprene mixing ratios were the highest at the 32 m in summer (1.64 ± 0.66 ppbV) and at 15 m in winter (1.41 ± 0.64 ppbV) with decreasing concentrations to the ground and to the 102 m, indicating emission from the tree canopy of the surrounding parks. Monoterpene mixing ratios were the highest at the 3 m height in both the winter (0.71 ± 0.42 ppbV) and summer (0.16 ± 0.10 ppbV) with a gradual decreasing trend to 102 m, indicting an emission from near the ground level. The lowest isoprene and monoterpene mixing ratios all occurred at 102 m, which were 0.71 ± 0.42 ppbV (winter) and 1.35 ± 0.51 ppbV (summer) for isoprene, and 0.42 ± 0.22 ppbV (winter) and 0.07 ± 0.06 ppbV (summer) for monoterpenes. Isoprene in the summer and monoterpenes in the winter, as observed at the five heights, showed significant mutual correlations. In the winter monoterpenes were positively correlated with combustion tracers CO and acetonitrile at 3 m, suggesting possible anthropogenic sources.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Compostos Orgânicos Voláteis/análise , Pequim , Monitoramento Ambiental , Monoterpenos/análise
17.
Chin J Nat Med ; 18(4): 243-249, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32402399

RESUMO

Mycosphazine A (1), a new iron(III) chelator of coprogen-type siderophore, and mycosphamide A (2), a new cyclic amide benzoate, together with six known aryl amides (3-8), were isolated from the fermentation broth of the deep-sea-derived fungus Mycosphaerella sp. SCSIO z059. Alkaline hydrolysis of 1 afforded a new epimer of dimerum acid, mycosphazine B (1a), and a new bi-fusarinine-type siderophore, mycosphazine C (1b). The planar structures of the new compounds were elucidated by extensive spectroscopic data analysis. The absolute configurations of amino acid residues in 1a and 1b were determined by acid hydrolysis. And the absolute configuration of 2 was established by quantum chemical calculations of the electronic circular dichroism (ECD) spectra. Compound 1 is the first siderophore-Fe(III) chelator incorporating both L-ornithine and D-ornithine unites. Compounds 3-8 were reported as natural products for the first time, and the 1H and 13C NMR data of 6 and 8 were assigned for the first time. Compounds 1 and 1a could greatly promote the biofilm formation of bacterium Bacillus amyloliquefaciens with the rate of about 249% and 524% at concentration of 100 µg·mL-1, respectively.


Assuntos
Ácidos Hidroxâmicos/metabolismo , Ferro/metabolismo , Mycosphaerella/metabolismo , Sideróforos/metabolismo , Organismos Aquáticos , Ácidos Hidroxâmicos/química , Ferro/química , Estrutura Molecular , Mycosphaerella/química , Sideróforos/química
18.
Nat Prod Res ; 34(14): 1992-2000, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30761921

RESUMO

Two new ß-carboline alkaloids, aspergillspins A-B (1-2), three new quinolone alkaloids, aspergillspins C-E (3-5), and two new isocoumarins, aspergillspins F-G (6-7), together with four known alkaloids were isolated from the marine gorgonian-derived fungus Aspergillus sp. SCSIO 41501. Their structures were identified by spectroscopic analysis, and the absolute configurations of several chiral carbons in 2 and 3 were further established by quantum chemical calculations of the electronic circular dichroism (ECD) spectra. Their cytotoxic and antibacterial activities were also evaluated.


Assuntos
Alcaloides/isolamento & purificação , Antibacterianos/isolamento & purificação , Aspergillus/química , Citotoxinas/isolamento & purificação , Isocumarinas/isolamento & purificação , Antibacterianos/química , Antibacterianos/farmacologia , Organismos Aquáticos/química , Dicroísmo Circular , Citotoxinas/química , Citotoxinas/farmacologia , Fungos/química , Isocumarinas/química , Conformação Molecular , Estrutura Molecular
19.
Sci Total Environ ; 699: 134357, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31683211

RESUMO

Diesel vehicle exhaust is an important source of carbonaceous aerosols, especially in developing countries, like China. Driving condition impacts diesel vehicle emissions, yet its influence needs further understanding especially on secondary organic aerosol (SOA) formation. In this study tailpipe exhaust from an in-use light duty diesel vehicle at idling and driving speeds of 20 and 40 km h-1 was introduced respectively into a 30 m-3 indoor smog chamber to investigate primary emissions and SOA formation during photo-oxidation. The emission factors of SO2 at 20 and 40 km h-1 were higher than those at idling, whereas the emission factors of aromatic hydrocarbons (AHs), polycyclic aromatic hydrocarbons (PAHs) and oxygenated volatile organic compounds (OVOCs) decreased when driving speeds increased. The emission factors of black carbon (BC) and primary organic aerosol (POA) at idling were comparable to those at 20 and 40 km h-1. The SOA production factors were 0.41 ±â€¯0.09 g kg-fuel-1 at idling, approximately 2.5 times as high as those at 20 km h-1 (0.16 ±â€¯0.09 g kg-fuel-1) or 40 km h-1 (0.17 ±â€¯0.09 g kg-fuel-1). Total carbonaceous aerosols, including BC, POA and SOA, from diesel vehicles at 20 and 40 km h-1 were 60-75% of those at idling, due largely to a reduction in SOA production. Measured AHs and PAHs altogether were estimated to explain <10% of SOA production, and eight major OVOCs could contribute 8.4-23% of SOA production. A preliminary comparison was further made for the same diesel vehicle at idling using diesel oils upgraded from China 3 to China 5 standard. The emission factors of total particle numbers decreased by 38% owing to less nuclei mode particles, which was probably caused by the reducing fuel sulfur content; the emission factors of BC were almost unchanged, the POA emission factors and SOA production factors however decreased by 72% and 37%.

20.
Org Lett ; 21(19): 7919-7922, 2019 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-31525876

RESUMO

A polyketide-derived alkaloid featuring a unique 3,4-dihydro-2H-indeno[1,2-b]pyridine 1-oxide motif, named phomopsol A (1), and a highly oxidized polyketide containing a new 3,5-dihydro-2H-2,5-methanobenzo[e][1,4]dioxepine moiety, named phomopsol B (2), were isolated from the Thai mangrove endophytic fungus Phomopsis sp. xy21, together with the related biosynthetic polyketide 3. The structures of 1-3 were unambiguously established by single-crystal X-ray diffraction analysis (Cu Kα), and their neuroprotective effects in PC12 cells were evaluated. The biosynthetic origins of 1-3 are proposed.


Assuntos
Fármacos Neuroprotetores/farmacologia , Policetídeos/farmacologia , Animais , Ascomicetos/química , Sobrevivência Celular/efeitos dos fármacos , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Modelos Moleculares , Estrutura Molecular , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/metabolismo , Células PC12 , Policetídeos/química , Policetídeos/metabolismo , Ratos , Estereoisomerismo , Relação Estrutura-Atividade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...