Population persistence of a Tertiary relict tree Tetracentron sinense on the Ailao Mountains, Yunnan, China.

The persistence of the Tertiary relict tree Tetracentron sinense Oliv. on the eastern slope of the Ailao Mountains, Yunnan, SW China, was here studied in terms of population structure (size, age) and regeneration patterns. T. sinense occurred in unstable habitats by stream banks, on steep slopes, on scree slopes, or on roadsides near streams in narrow valleys, all places subject to frequent natural disturbances, whereas none were found on stable gentle slopes free of major disturbances at similar altitudes. Further, no established saplings of T. sinense were found in forests having high bamboo (Yushania crassicollis Yi) coverage in their understory. The size and age structure of T. sinense were multimodal. The reproduction of the tree was either by means of abundant minute wind-dispersed seeds or by resprouts in unstable habitats. These populations depended on disturbance or gap regeneration to survive. T. sinense, along with other tree life-forms including evergreen broad-leaved species and conifers, dominated in the forest canopy layer, even reaching the emergent layer in places. Results of the study provide insight into the ecological characteristics and survival mechanisms of this East Asian paleoendemic tree species. The study will provide a scientific basis for recommendations for the conservation of this species and for other Tertiary relict plants having similar regeneration dynamics.

Effect of ß­ecdysterone on glucocorticoid­induced apoptosis and autophagy in osteoblasts.

The aim of the present study was to investigate the effect of glucocorticoids in osteoblasts and to examine the role of ß­ecdysterone in the pathogenesis of glucocorticoid­induced osteoporosis. Osteoblasts were induced from bone marrow mesenchymal stem cells, which were isolated from C57BL/6 mice. Cell viability and apoptosis of osteoblasts were measured by Cell Counting Kit­8 and flow cytometry analysis, respectively. The expression of related genes and proteins was measured by reverse transcription quantitative polymerase chain reaction and western blot analysis respectively. Dose­dependent decreases in the cell proliferation and differentiation were observed in dexamethasone (Dex)­treated osteoblasts, evidenced by downregulation in the activity of alkaline phosphatasedecreased expression levels of Runt­related transcription factor 2 and osteocalcin, and upregulated expression of RANK ligand. Dex also induced apoptosis and inhibited autophagy of osteoblasts, evidenced by upregulated B­cell lymphoma 2 (Bcl­2)­associated X protein/Bcl­2 ratio and the activation of mammalian target of rapamycin (mTOR), and decreased expression levels of Beclin­1, autophagy protein 5 and microtubule­associated protein 1 light chain 3 II. The effects on cell proliferation, apoptosis and autophagy induced by Dex were reversed by ß­ecdysterone in a dose­dependent manner. Therefore, ß­ecdysterone may be a promising candidate drug for the treatment of osteoporosis through inducing osteoblast autophagic activity by inactivating mTOR.

[Population and distribution of western black crested gibbon (Nomascus concolor) at Ailao Mountain, Xinping, Yunnan].

The western black crested gibbon (Nomascus concolor) is mainly distributed in Yunnan, China. Ailao Mountain is located in central Yunnan and divided into three prefectures and six counties. This mountain forms the principle distribution range for western black crested gibbon; however, there are no published data on the gibbon population inhabiting the Xinping administrative. Take the interview results conducted in 2007 and 2009 with local people as the reference, this study conducted an extensive field survey covering all possible habitats from November 2009 to January 2010 using call surveys. Among the one hundred and twenty-four gibbon groups which were confirmed across the Ailao Mountain, the largest known population of western black crested gibbons yet, 85 groups inhabit the national nature reserve and adjacent national forest, 30 groups inhabit the provincial nature reserve and nine groups inhabit the collective forest located outside the reserve and national forest. We found that the western black crested gibbons here have a patchy distribution pattern and occur at higher densities in certain areas. Moreover, the population distribution density and elevation gradient distribution decline from north to south. The results also demonstrated the importance of Ailao Mountain in the western black crested gibbon protection.