Quinolinones Alkaloids with AChE Inhibitory Activity from Mangrove Endophytic Fungus Penicillium citrinum YX-002.

Acetylcholinesterase (AChE) inhibitory activity-guided studies on the mangrove-derived endophytic fungus Penicillium citrinum YX-002 led to the isolation of nine secondary metabolites, including one new quinolinone derivative, quinolactone A (1), a pair of epimers quinolactacin C1 (2) and 3-epi-quinolactacin C1 (3), together with six known analogs (4-9). Their structures were elucidated based on extensive mass spectrometry (MS) and 1D/2D nuclear magnetic resonance (NMR) spectroscopic analyses, and compared with data in the literature. The absolute configurations of compounds 1-3 was determined by combination of electronic circular dichroism (ECD) calculations and X-Ray single crystal diffraction technique using CuKα radiation. In bioassays, compounds 1, 4 and 7 showed moderate AChE inhibitory activities with IC50 values of 27.6, 19.4 and 11.2 µmol/L, respectively. The structure-activity relationships (SARs) analysis suggested that the existence of carbonyl group on C-3 and the oxygen atom on the five-membered ring were beneficial to the activity. Molecular docking results showed that compound 7 had a lower affinity interaction energy (-9.3 kcal/mol) with stronger interactions with different sites in AChE activities, which explained its higher activities.

Source profiles and emission factors of organic and inorganic species in fine particles emitted from the ultra-low emission power plant and typical industries.

Accurate source markers, source profiles and species-based emission factors (EFs) are currently the key limitations for source apportionment and emission inventory researches. Fine particles (PM2.5) were collected from stack gases of eight types of stationary sources with a dilution sampling system. The mass percentages and EFs of 89 kinds of chemical species in PM2.5 including water-soluble ions, elements, carbonaceous species and molecular organic species were obtained. Results showed that water-soluble ions (8%-54%) and elements (5%-45%) were the dominant chemical species. Palmitic acid (0.19%-0.62%) and stearic acid (0.21%-0.59%) were the most abundant organic species. PM2.5 source profiles of the eight sources were different from each other with the coefficient of divergence values all higher than 0.4. The addition of organic species could help to further distinguish them. The indicatory chemical components and specific species ratios were obtained by both a statistical equation and randomForest. These indicatory chemical components (e.g. F- for glass factory) and species ratios (e.g. K+/Mg2+ & OC/Mg for pharmaceutical factory) improved the current knowledges of their indicatory performance in source identification of ambient PM2.5. The EFs of PM2.5 from the eight stationary sources ranged from 0.019 to 51.6 kg t-1 of fuel used. The EFs of PM2.5 from the pharmaceutical factory were about 70-2600 times higher than other seven types of sources due to the lack of dust-removing devices. Certain EFs measured in this study were about 10-36,000 times lower than corresponding EFs estimated in previous studies which didn't perform field measurements, indicating the necessity for improving emission inventories continuously. This study contributes to identifying emission sources of PM2.5 especially for subtypes of stationary sources and to establishing species-based emission inventories.

Temperature dependence of source profiles for volatile organic compounds from typical volatile emission sources.

Source profiles of volatile organic compounds (VOCs) emitted from the evaporation of various fuels, industrial raw materials, processes and products are still limited in China. The impact of ambient temperature on the VOC released from these fugitive emission sources has also been rarely reported. In order to establish VOC source profiles for thirteen volatile emission sources, a sampling campaign was conducted in Central China, and five types of sources were investigated both in winter and summer. The dominant VOC groups varied in different sources, and they were alkanes (78.6%), alkenes (53.1%), aromatics (55.1%), halohydrocarbons (80.7%) and oxygenated VOCs (OVOCs) (76.0%), respectively. Ambient temperature showed different impacts on VOC source profiles and specific species ratios. The mass percentages of halohydrocarbons emitted from color printing and waste transfer station in summer were 42 times and 20 times higher than those in winter, respectively. The mass percentages of OVOCs emitted from car painting, waste transfer station and laundry emission sources were much higher in summer (7.9-27.8%) than those in winter (0.8-2.6%). On the contrary, alkanes from color printing, car painting and waste transfer stations were about 11, 4 and 5 times higher in winter than those in summer, respectively. The coefficient of divergence values for the source profiles obtained in winter and summer ranged in 0.3-0.7, indicating obvious differences of source profiles. Benzene/toluene ratio varied in 0.00-0.76, and it was in the range of 0.02-0.50 in winter and 0.04-0.52 in summer for the same sources, respectively. Hexanal, isobutene, m,p-xylene, toluene, 2-methylacrolein, styrene, 1-hexane and cis-2-butene dominated the ozone formation potentials (OFP). The OFP summer/winter differences were 5-320 times by MIR method and 1-79 times by Propy-Equiv method, respectively. This study firstly gave direct evidence that ambient temperature modified the mass percentages of VOC species obviously. It is important for improving VOC source apportionment and chemical reactivity simulation.

Size-segregated carbonaceous aerosols emission from typical vehicles and potential depositions in the human respiratory system.

Particles emitted from five typical types of vehicles (including light-duty gasoline vehicles, LDG; heavy-duty gasoline vehicles, HDG; diesel buses, BUS; light-duty diesel vehicles, LDD and heavy-duty diesel vehicles, HDD) were collected with a dilution sampling system and an electrical low-pressure impactor (ELPI+, with particle sizes covering fourteen stages from 6 nm to 10 µm) on dynamometer benches. The mass concentrations and emission factors (EF) for organic carbon (OC) and elemental carbon (EC) were obtained with a DRI Model 2001 thermal/optical carbon analyzer. A respiratory deposition model was used to calculate the deposition fluxes of size-segregated carbonaceous aerosols in human respiratory system. Results indicated that the OC produced from LDG mainly existed in the size range of 2.5-10 µm, while EC from HDG enriched in 0.94-2.5 µm. For diesel vehicles, both OC and EC concentrations peaked at 0.094-0.25 µm. The OC/EC ratios for PM2.5 varied from different types of vehicles, from 0.61 to 8.35. The primary emissions from LDD and HDD exhibited high OC/EC ratios (>3), suggesting that using OC/EC higher than 2 to indicate the formation of secondary organic aerosol (SOA) was not universal. The emission factors for OC and EC of LDG (HDG) in PM10 were 1.78 (3.14) mg km-1 and 0.88 (4.32) mg km-1, respectively. The OC2 and OC3 were the main section (over 60%) of OC emitted from all the five types of vehicles. EC1 was the most abundant EC fraction of LDG (76.9%), while EC2 dominated for other types of vehicles (more than 62%). About 60% of the OC in ultrafine particles could be deposited in the alveoli. Diesel EC mainly could be deposited in the alveolar region. It is necessary to control the emission of ultrafine particles and diesel EC.