Expression Pattern and Regulatory Role of microRNA-23a in Conjugated Linoleic Acids-Induced Apoptosis of Adipocytes

Background/Aims: Conjugated linoleic acids (CLAs) are known to induce apoptosis in adipocytes; however, the cellular mechanisms involved remained illdefined. We explored the different apoptotic induction effects of two CLA isomers on adipocytes and then investigated the expression and function of microRNAs (miRNAs) related to the apoptosis. Methods: TUNEL and FCM assays were used to detect CLAs-induced adipocyte apoptosis. Microarrays were used to compare the differential expression of miRNAs. MiR-23a, a miRNA that showed significant changes in expression in the CLA-treated cells, was selected for the subsequent functional studies via over-expression and knock down in in vivo and in vitro experiments. Results: C9, t11-CLA exhibited a stronger induction of apoptosis in the differentiated 3T3-L1 adipocytes than t10, c12-CLA. However, t10, c12-CLA could rapidly activate NF-κB, which may have caused their different apoptotic effects. MiR-23a was markedly down-regulated by the CLAs treatment and miR-23a over-expression attenuated CLA-induced apoptosis. Apoptosis protease-activating factor 1 (APAF1) was identified as a target gene of miR-23a. In an in vivo experiment endogenous miR-23a was down-regulated in mice fed with a mixture of both CLAs. The mice also exhibited less fat deposition and more apoptotic fat cells in adipose tissue. Moreover, endogenous miR-23a was suppressed in mice via intravenous injection with an antagomir which resulted in decreased body weight, increased number of apoptotic fat cells and increased APAF1 expression in adipose tissue. Conclusion: Taken together, our results suggest that miR-23a plays a critical role in CLA-induced apoptosis in adipocytes via controlling APAF1 expression

Using expert knowledge to identify key threats and conservation strategies for wildlife: A case study with bats in China

Global biodiversity is in rapid decline, yet the key threats to wildlife in many regions remain uncertain. Bats are one of the most diverse mammalian groups, playing vital roles in the ecosystems. There are at least 140 bat species in China, with 30 % of being regionally threatened or data deficient. Here, we used expert elicitation to assess the key threats and conservation strategies of bats in China. We designed an online questionnaire concerning the conservation of Chinese bats, and then distributed the questionnaire to bat experts worldwide via email. All participants were asked to rank each threat and conservation strategy according to the urgency and significance. After excluding participants without some knowledge of Chinese bats and conservation biology, we gathered the opinions of 119 bat experts from China and abroad. The results showed that the scores of different threats and conservation strategies were predicted by their categories. Loss of habitat, killing and hunting, and roost disturbance were regarded as the three top threats faced by Chinese bats. Most experts recognized that banning hunting and improving the legislation were two priority strategies for bat conservation, although monitoring of bat diversity, scientific publicity, and education were also important. Nearly 98 % of the experts supported the suggestion that threatened bats should be under special state protection because of their ecological services, economic value, population decline, scientific value, and other features. These results provide valuable implications for guiding the protection and management of bats in China

Effects of canopy gaps on N2O fluxes in a tropical montane rainforest in Hainan of China

Background and aims: Tropical montane rainforests play an important role in increasing atmospheric N2O concentration. Although accurate estimations of N2O fluxes in tropical montane rainforests are critical for predicting global climate change, there are still considerable uncertainties about the spatial and temporal variability of the emissions. This study aims to investigate the effects of canopy gap caused by typhoons on N2O emissions, a key factor for understanding the spatial heterogeneity and supporting environmental regulations. Methods: N2O fluxes were measured monthly using static chambers both inside and outside two large canopy gaps in the tropical montane rainforest of the Jianfengling National Natural Reserve on Hainan Island, south of China, from August 2012 to July 2013. Results: Mean annual N2O emissions were 2.19 +/- 0.43 kg N2O-N ha(-1) yr(-1) inside canopy gaps, and 1.19 +/- 0.29 kg N2O-N ha(-1) yr(-1) outside canopy gaps, revealing substantial differences in N2O emissions resulting from forest structure. Moreover, N2O emission rates within canopy gaps during the wet season (2.89 kg N2O-N ha(-1) yr(-1)) were significantly higher than those during the dry season (1.34 kg N2O-N ha(-1) yr(-1)), suggesting strong regulation of soil moisture and precipitation in controlling soil N dynamics. However, there were significant nonlinear relationships between N2O fluxes and water filled pore space, and soil temperature within canopy gaps, but no significant relationships were found under the closed canopy. Conclusions: Contribution of canopy gaps should be considered to avoid underestimation of N2O emission rates from disturbed forests. Interestingly, emissions from gaps are more strongly coupled with climate drivers (moisture and temperature), with important implications for climate change projections. Therefore, the further research is needed to study the biogeochemical processes and mechanisms behind such phenomenon. (C) 2017 Elsevier B.V. All rights reserved