Dihydro-ß-agarofuran-type sesquiterpenoids from the seeds of Celastrus virens with lifespan-extending effect on the nematode Caenorhabditis elegans.

Twelve dihydro-ß-agarofuran-type sesquiterpenoids, including five new ones (1-5), were purified from the seeds of Celastrus virens (Wang et Tang) C. Y. Chent et T. C. Kao. Their chemical structures were characterized via comprehensive spectroscopic analysis, single-crystal X-ray diffraction analysis, and computational prediction of ECD, as well as comparison of observed and reported NMR spectral data. Among the isolates, nine abundant dihydro-ß-agarofuran-type sesquiterpenoids were evaluated for their lifespan-extending activity using the nematode Caenorhabditis elegans model. As a result, compounds 1, 2, 5, 6, 8, and 9 (50 µM) significantly extended the mean survival time of C. elegans, respectively, compared with the blank control group (p < 0.05). Further Quantitative RT-PCR showed that the prolonging of lifespan mediated by compounds 1, 6, 8, and 9 were dependent on the transcription factors skn-1 and hsf-1.

[Spatial-temporal differentiation of mountain-water-forest-farmland-lake-grass system in Qinghai area of the Qilian Mountain National Park, China]. / ç¥è¿žå±±å›½å®¶å ¬å›­é’æµ·ç‰‡åŒºå±±æ°´æž—ç”°æ¹–è‰çš„æ—¶ç©ºåˆ†å¼‚.

Higher and more precise requirements are critically needed for the protection, regulation, and restoration of ecological environment in the Qilian Mountain National Park after it is classified as a national park system pilot in China. Based on remote sensing data in 1980-2018, the spatial pattern map of mountain-water-forest-farmland-lake-grass system was constructed to analyze its spatial-temporal variations in the general control area and core conservation area in Qinghai area of the Qilian Mountain National Park. The results showed that grasslands, with an area of 8174.93 km2, were the main landscape in the park, and that grassland area in the core conservation area was 1.2 times as that of the general control area. The bare exposed rocks, a major type of unused land, accounted for 86.7% and 79.4% of the unused land in the core conservation area and the general control area, respectively. Forest area in the general control area was larger than that in the core conservation area. Water area in the core conservation area was 4.9 times as large as that in the general control area, with 90.4% of which being dominated by permanent glaciers and snowfields. The drylands were mainly concentrated in the general control area. From 1980 to 2018, the water area was decreasing and had been reduced by 186.75 km2. The area of permanent glaciers and snowfields decreased the most, with a drop of 12.05 and 175.88 km2 in the general control area and the core conservation area, respectively. The area of forests and grasslands were enlarged constantly. The changes of high-, medium-, and low-coverage grasslands in the core conservation area were greater than that in the general control area, which were the most significant during 1990-2000. Moreover, the degradation of high- and medium-coverage grasslands in the general control area as well as high- and low-coverage grasslands in the core conservation area was observed from 1980 to 2018. The area of bare exposed rocks was on the rise, while the permanent glaciers and snowfields displayed a decreasing trend. The permanent glaciers and snowfields and the bare exposed rocks exhibited the most obvious changes in the park. The glaciers in the core conservation area retreated remarkably faster than those in the general control area, which were transformed into the bare exposed rocks mainly in 1980-1990 and 2000-2010.

[Changes of growing season NDVI at different elevations, slopes, slope aspects and its relationship with meteorological factors in the southern slope of the Qilian Mountains, China from 1998 to 2017]. / 1998­2017年祁连山南坡不同海拔、坡度和坡向生长季NDVIå˜åŒ–åŠå ¶ä¸Žæ°”è±¡å› å­çš„å ³ç³».

Qilian Mountains is an important water conservation area in Northwest China, which is the boundary between the first and second steps of China's topography and is sensitive to climate change. Based on the data of temperature, precipitation, normal difference vegetation index (NDVI), and digital elevation model (DEM) data, we analyzed NDVI change and its relationship with temperature and precipitation along the elevation, slope and slope aspect in the southern slope of Qilian Mountains using tendency analysis method, wavelet analysis and correlation analysis. The results showed that, from 1998 to 2017, NDVI value of the growing season presented increasing trend by a rate of 0.023·10 a-1. Changes of NDVI differed at different elevations, slopes and slope aspects. NDVI increased first and then decreased with elevation. The vegetation coverage at 2700-3700 m was good, and degraded in the area of >4700 m. NDVI reduced with the increases of slope, which showed little difference in different slope aspects but was better in sunny slope than in shade slope. NDVI of the growing season was closely related with temperature and precipitation. NDVI, temperature and precipitation in growing season all had a 14-year cycle. Vegetation at different elevations, slopes and slope aspects was differently affected by temperature and precipitation. Vegetation in areas with altitude <3700 m, >4700 m, slope <25° and each slope direction was more sensitive to precipitation.

[Land use change and its driving force on the southern slope of Qilian Mountains from 1980 to 2018]. / 1980­2018å¹´ç¥è¿žå±±å—å¡åœŸåœ°åˆ©ç”¨å˜åŒ–åŠå ¶é©±åŠ¨åŠ›.

Qilian Mountains is the boundary of the first and second steps of China's terrain, with fragile ecological environment. There is great ecological significance to study land use change and driving force in transitional areas. In this study, we investigated the spatial and temporal characte-ristic of land use and its driving force in the south slope of Qilian Mountains, based on RS image data from 1980 to 2018, with the spatial autocorrelation method, ArcGIS spatial analysis method and principal component analysis. The results showed that, from 1980 to 2018, grassland was the main land use type, and the proportion of construction land was the smallest. Water area and grassland showed a declining trend, while unused land, construction land and farmland showed an increasing trend. There was smaller change for the woodland. The single dynamic degree of different land types decreased following an order of construction land, water, farmland, unused land, woodland and grassland. The comprehensive dynamic degree of land use was 0.9%. The spatial distribution of different land use types showed the characteristics of spatial agglomeration. The increased areas of farmland and the decreased areas of woodland and grassland were mainly distributed in the northwest of the Datong River valley of Menyuan County, while in the upper reaches of Datong River in the northeast of Tianjun County, grassland was occupied by construction land. The driving force of land use was population, science and technology, urbanization, level of economic development, and policies. Our results would support the government to reasonably plan and utilize land resources, which is of significance to the protection of ecological environment and the sustainable development of society and economy on the southern slope of Qilian Mountains.