[A neuritogenic compound from Tremella fuciformis].

OBJECTIVE: To search for low-molecular-weight neuritogenic compounds from the traditional Chinese medicine (TCM). METHOD: An extract library of TCM was prepared. Targeted isolation guided by biological screening led to the discovery of compound 1, and its structure was elucidated by analysis of spectroscopic methods and comparison of spectroscopic data with these reported from the literature. RESULT: A neuritogenic compound 1, 3-O-beta-D-glucopyranosyl-22E, 24R-5alpha, 8alpha-epidioxyergosta-6, 22-diene, was isolated and identified from the methanol extract of T. fuciformis. This compound showed a significant neuritogenic activity against PC12 cells at 3 micromol x L(-1)). CONCLUSION: Methonal extract of T. fuciformis and targeted compound 1 both showed significant neuritogenic activity against PC12 cells. These results suggested that the extract and compound 1 might be used to prevent and treat neurodegenerative disease such as Alzheimer's disease.

[Contribution of water soluble organic nitrogen to total nitrogen in atmospheric aerosols in Qingdao].

Organic nitrogen (ON) is a quantitatively important component of reactive nitrogen in atmospheric aerosols. Deposition of ON in seawater from atmosphere could enhance primary productivity, as well as with the changes in the phytoplankton community composition. 64 total suspended particles (TSP) samples collected at Qingdao from January to December in 2008 were applied to analyze the concentrations of water soluble organic nitrogen in aerosols. Concentrations of ON in Qingdao aerosols ranged from 30 to 2073 nmol x m(-3) (100-12 157 micromol x g(-1)), with the highest values occurring in December, followed in March and April and the lowest values in June to September. ON mean concentration in TSP in 2008 was 430 nmol x m(-3) (2 323 micromol x g(-1)). The contribution of ON to total nitrogen (TN) was (37.5 +/- 21.6)%, with the maximum presenting in December and the minimum in September. The distribution of organic nitrogen in aerosols was significantly affected by the weather conditions. During haze and fog episodes, the concentrations of ON in the aerosols were 789 nmol x m(-3) and 412 nmol x m(-3), respectively, 4 times and twice higher than that during clear episodes. However, the particle mass concentrations in haze and fog days were comparable with that in clear days. During dust episodes, the concentration of particles was 5 times higher than that during clear episodes while ON concentration slightly enhanced 0.4 times. The ON concentration in aerosols after raining was 57 nmol x m(-3), decreased 80% than that before raining due to the efficient wet scavenging.

[Distributions of dissolved and particulate amino compounds in atmospheric aerosols at Qingdao].

Amino compounds is one class of organic nitrogen compounds that has been measured extensively in aerosols and rainwater. These compounds in atmospheric deposition might have a potential role in marine ecosystem since it can be directly utilizable sources of nitrogen for microorganisms and plants. 66 total suspended particles samples were collected at Qingdao from January to December in 2008. Concentrations of dissolved amino compounds (DAC) and particulate amino compounds (PAC) were analyzed using precolumn fluorescence derivatization with o-phthaldialdehyde and N-isobutyryl-L-cysteine, combined with reverse-phase high performance liquid chromatography. Concentrations of DAC in Qingdao aerosols ranged from 2.4 to 40.9 nmol x m(-3), with highest values occurring in spring, followed in summer and lowest values in autumn and winter. PAC concentration were from 0.7 to 76.1 nmol x m(-3), presenting the seasonal trend of spring > winter > autumn > summer. Compositions of amino compounds in aerosols varied seasonally. By classifying air mass back trajectories during each sampling period, the aerosol samples in Qingdao were mainly influenced by northerly continental source, southerly continental source and marine source. Concentrations of DAC and PAC were found highest in the samples influenced by southerly continental source, followed by northerly continental source and lowest in the samples by marine source. Compositions of amino compounds were also influenced by the sources. Contributions of protein-type to total amino compounds were highest in the aerosols from marine source and lowest in the aerosols from southerly continental source.

[Urea in aerosol and rainwater over the East China Sea in winter and spring].

Organic nitrogen is a quantitatively important component of fixed nitrogen in atmospheric aerosol and rainwater. Urea as a possible candidate of organic nitrogen component might have a significant influence to the marine ecosystem since its bioavailability and broad range of natural and anthropogenic sources. 23 total suspended particulate samples, 4 size-segregated particles samples and 10 rainwater samples collected over the East China Sea from Nov. to Dec., 2006 and Feb. to Mar., 2007 were applied to analyze the concentrations of urea, nitrate and ammonium in aerosols and rainwater, respectively. In winter and spring, the concentrations of urea nitrogen were from 0.2 nmol m(-3) to 17.7 nmolx m(-3) and 6.5 nmol x m(-3) to 14.6 nmol x m(-3) in bulk aerosols, respectively and the corresponding concentrations were from 7.8 miromol x L(-1) to 18.1 micromol x L(-1) and 12.1 micromol x L(-1) to 35.3 micromol x L(-1) in rainwater. In both aerosols and rainwater over the East China Sea, the concentrations of urea nitrogen were higher in spring than those in winter. Urea nitrogen in aerosols contributed about 5% to the three measured nitrogen species and it was about 20% in rainwater. The size distribution of urea was markedly different from those of nitrate and ammonium,which had no pronounced difference among cascade stages. A slightly enhance urea contribution presented in the range of 0.43-0.65 microm in spring, which was 19.8%. In contrast, an enhancement presented in the range of 3.3-4.7 microm in winter, which was 19.8%. Factor analysis indicated that the sources of urea in aerosols were dominated by wind-blown soils in winter and sublime of urea in soils in spring, respectively.