[Spatial Distribution of Nitrogen and Phosphorus Nutrients in the Main Stream and Typical Tributaries of Tuojiang River and Fujiang River].

The Tuojiang River and Fujiang River, two important tributaries of the upper reaches of the Yangtze River, have serious water pollution problems, among which nitrogen (N) and phosphorus (P) are the most important pollutants. Therefore, the aim of this study was to identify the influencing factors of water quality in different spaces and provide a scientific basis for the prevention and control of surface water pollution in the upper reaches of the Yangtze River and its tributaries. Water samples of trunk and tributaries in the Tuojiang River and Fujiang River were collected, and the spatial distribution characteristics of water N and P were analyzed. The results showed that the Tuojiang River and Fujiang River showed serious pollution of total nitrogen (TN), with a water quality worse Ⅴ-section proportion as high as 94% and 50%, respectively. Both rivers showed that TN and TP concentrations in the tributaries were higher than those in the main stream. For both rivers, total phosphorus (TP), with moderate pollution, was mainly concentrated in Ⅱ, Ⅲ, and Ⅳ class water quality, whereas the P pollution was more serious for the Fujiang River compared to that of the Fujiang River. For the Tuojiang River, nitrate nitrogen (NN) concentration from upstream to downstream showed a trend of decreasing after the first increase, with the maximum concentration of ammonium nitrogen (AN) exhibiting at the upstream site. In particular, TP concentration increased significantly after rivers flowed through a city. For the Fujiang River trunk stream, TN and NN concentration exhibited a gradually increasing trend from the middle to lower reaches. Generally, our study revealed that TN, TP, and NN in the rivers were affected by water pH and water temperature (T). Therefore, the control of N and P pollution in rivers should pay attention to the influence of water environmental factors.

[Ginsenoside Rh2 induces apoptosis and autophagy of K562 cells by activating p38].

To study the effect of ginseng saponin Rh2 in inducing apoptosis of human leukemia K562 cells, and explore its mechanism from the aspect of autophagy pathway. CCK-8 assay was used to examine the growth inhibition of human leukemia cell lines K562 treated with ginsenoside Rh2; flow cytometry (FCM) was used to detect cell apoptosis; Hoechst staining was used to observe the changes of cell morphological apoptosis; Acridine and MDC staining were used to detect the effects of the Rh2 on autophagy; Western blot and RT-PCR were used to detect the expression levels of the proteins closely associated with autophagy and apoptosis. In order to study the effect of autophagy in proliferation and apoptosis, we used the autophagy inhibitor (3-MA).CCK-8 indicated that Rh2 at low concentration could effectively inhibit the proliferation of leukemia cellsin dose- and time-dependent manners in K562 cells; FCM indicated that Rh2 induced apoptosis; Hoechest staining showed that K562 cells had typical apoptotic morphological changes by treated Rh2; Acridine and MDC staining showed that Rh2 enhanced the green fluorescence and a large number of acidic autophagy vesicles were present; Western blot and RT-PCR results showed that Rh2 increased the expression levels of Beclin-1, LC3A, LC3B, activated Caspase-3 and p-p38 in K562 cells; application of autophagy inhibitors(3-MA) could weaken the inhibition effect of Rh2 on proliferation and induction effect on apoptosis in K562 cells. Ginsenoside Rh2 inhibited the proliferation and induced apoptosis probably through activating p-p38, and inducing cell autophagy signaling pathway in K562 cells.