The alkaloids with neuroprotective effect from the root bark of Ailanthus altissima.

The chemical constituent investigation on the root bark of Ailanthus altissima leads to the isolation of a new ß-carboline alkaloid, 14(S),15-dihydroxy-6-methoxy-ß-carboline (1), along with nine known alkaloids. The structure of new compound was elucidated on basis of extensive spectroscopic analysis, especially two-dimensional (2D) NMR techniques and the absolute configuration of C-14 was determined by ECD calculation. The neuroprotective effect of the isolated compounds on PC12 cells against the serum deprivation injury was evaluated by MTT method. As a result, compound 7 revealed protective effect on PC12 cells and the cell survival rate was significantly increased.

A distinct whole nucleus stain pattern of gamma H2AX induced by N-methyl-No-nitro-N-nitrosoguanidine / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To characterize the DNA damage property represented by the distinct whole nucleus stain pattern of gammaH2AX induced by N-methyl-No-nitro-N-nitrosoguanidine (MNNG).</p><p><b>METHODS</b>MNNG-induced gammaH2AX foci formation in human amnion FL cells was observed by immunofluorescent microscopy. DNA double-stranded breaks (DSBs) were detected by neutral comet assay. General DNA damages were detected by alkaline comet assay.</p><p><b>RESULT</b>A distinct whole nucleus stain pattern of gammaH2AX was induced by high concentration MNNG (10 mg/L). 1 mg/L MNNG also induced this type of stain pattern in a small fraction of cells, although the effect was transient. Neutral comet assay did not detect any significant DSBs formation in this type of cells, while alkaline comet assay revealed the presence of DNA damage.</p><p><b>CONCLUSION</b>Although normal gammaH2AX foci were regarded as a biomarker for DSBs, the whole nucleus stain pattern might represent DNA damage other than DSBs.</p>

[Determination of metal ions in tobacco and application of clustering analysis].

The contents of potassium, magnesium, sodium, manganese, ferrum and zinc were determined by flame spectrometry and atomic absorption spectrometry respectively. The dataset was clustered by fuzzy c-means (FCM) clustering analysis and hierarchical clustering analysis. It is shown that the results of the FCM clustering analysis are more accurate than those of the hierarchical cluster analysis, and it is with positive meaning to apply FCM clustering analysis to estimating the producing area of tobaccos.