Conifers in Mountains of China

China has the largest area of mountains of all countries, with about 70% of land territory covered with mountains and plateaus. Thanks to vastness, mountainousness, highly heterogeneous habitats and long history of biological evolution, China boasts of extremely high biodiversity (more than 30,000 species of seed plants). The objectives of this chapter are to investigate conifer species and to analyze their multi-dimensional distribution in China. Our conclusions include: (1) China has 244 species of conifers belonging to 32 genera in 4 families (Pinaceae, Cupressaceae, Podocarpaceae and Taxaceae), accounting for 38.37, 49.29 and 66.67% of the global totals, respectively; (2) there are totally 115 conifer species endemic to China, falling in 23 genera of 4 families; (3) conifers and coniferous forests are widely distributed in China, from north to south and from east to west, more prominently in its numerous and high mountains and plateaus; (4) some conifer species appear even at very high elevations, e.g., Juniperus tibetica forests at 4800–4900 m above sea level in the southeastern Tibetan Plateau; and (5) China has established a large number of nature reserves and promulgated and implemented a series of laws and regulations to protect its rare and precious conifer resources

Brain Functional Networks in Type 2 Diabetes Mellitus Patients: A Resting-State Functional MRI Study

BackgroundPrevious diabetes mellitus studies of cognitive impairments in the early stages have focused on changes in brain structure and function, and more recently the focus has shifted to the relationships between encephalic regions and diversification of network topology. However, studies examining network topology in diabetic brain function are still limited.MethodsThe study included 102 subjects; 55 type 2 diabetes mellitus (T2DM) patients plus 47 healthy controls. All subjects were examined by resting-state functional magnetic resonance imaging (rs-fMRI) scan. According to Automated Anatomical Labeling, the brain was divided into 90 anatomical regions, and every region corresponds to a brain network analysis node. The whole brain functional network was constructed by thresholding the correlation matrices of the 90 brain regions, and the topological properties of the network were computed based on graph theory. Then, the topological properties of the network were compared between different groups by using a non-parametric test. Finally, the associations between differences in topological properties and the clinical indicators were analyzed.ResultsThe brain functional networks of both T2DM patients and healthy controls were found to possess small-world characteristics, i.e., normalized clustering coefficient (γ) > 1, and normalized characteristic path length (λ) close to 1. No significant differences were found in the small-world characteristics (σ). Second, the T2DM patient group displayed significant differences in node properties in certain brain regions. Correlative analytic results showed that the node degree of the right inferior temporal gyrus (ITG) and the node efficiencies of the right ITG and superior temporal gyrus of T2DM patients were positively correlated with body mass index.ConclusionThe brain network of T2DM patients has the same small-world characteristics as normal people, but the normalized clustering coefficient is higher and the normalized characteristic path length is lower than that of the normal control group, indicating that the brain function network of the T2DM patients has changed. The changes of node properties were mostly concentrated in frontal lobe, temporal lobe and posterior cingulate gyrus. The abnormal changes in these indices in T2DM patients might be explained as a compensatory behavior to reduce cognitive impairments, which is achieved by mobilizing additional neural resources, such as the excessive activation of the network and the efficient networking of multiple brain regions

Disrupted Functional Network Topology in Children and Adolescents With Post-traumatic Stress Disorder

Neuroimaging studies in children and adolescents with post-traumatic stress disorder (PTSD) have focused on abnormal structures and the functionality of a few individual brain regions. However, little is known about alterations to the topological organization of whole-brain functional networks in children and adolescents with PTSD. To this end, we investigated the topological properties of brain functional networks derived from resting-state functional magnetic resonance imaging (r-fMRI) in patients suffering from PTSD. The r-fMRI data were obtained from 10 PTSD patients and 16 trauma-exposed non-PTSD subjects. Graph theory analysis was used to investigate the topological properties of the two groups, and group comparisons of topological metrics were performed using nonparametric permutation tests. Both the PTSD and non-PTSD groups showed the functional brain network to have a small-world architecture. However, the PTSD group exhibited alterations in global properties characterized by higher global efficiency, lower clustering coefficient, and characteristic path length, implying a shift toward randomization of the networks. The PTSD group also showed increased nodal centralities, predominately in the left middle frontal gyrus, caudate nucleus, and hippocampus, and decreased nodal centralities in the left anterior cingulate cortex, left paracentral lobule, and bilateral thalami. In addition, the clustering coefficient and nodal betweenness of the left paracentral lobule were found to be negatively and positively correlated with the re-experiencing and hyper-arousal symptoms of PTSD respectively. The findings of disrupted topological properties of functional brain networks may help to better understand the pathophysiological mechanism of PTSD in children and adolescents

The Ets Transcription Factor GABP Is a Component of the Hippo Pathway Essential for Growth and Antioxidant Defense

这是周大旺教授继2009年首次发现了Hippo信号通路在哺乳动物中控制器官大小及肿瘤发生具有重要作用后的又一重大研究成果，该研究系统阐述了 YAP基因在转录调控水平上的的调控机理，进一步完善了人们对Hippo信号通路的认识，也为由YAP调控异常所引发的癌症提供了一个潜在的治疗靶点。 该论文的第一作者为博士生吴黉坦和硕士生肖玉波和张世浩, 通讯作者是周大旺教授和陈兰芬副教授，该工作是与厦门市中医院、中山医院和医学高等专科学校等单位合作完成的。周大旺教授是中央首批“青年千人计划”入选者并获得国家首批“优秀青年科学基金”资助。The transcriptional coactivator Yes-associated protein (YAP) plays an important role in organ-size control and tumorigenesis. However, how Yap gene expression is regulated remains unknown. This study shows that the Ets family member GABP binds to the Yap promoter and activates YAP transcription. The depletion of GABP downregulates YAP, resulting in a G1/S cell-cycle block and increased cell death, both of which are substantially rescued by reconstituting YAP. GABP can be inactivated by oxidative mechanisms, and acetaminophen-induced glutathione depletion inhibits GABP transcriptional activity and depletes YAP. In contrast, activating YAP by deleting Mst1/Mst2 strongly protects against acetaminophen-induced liver injury. Similar to its effects on YAP, Hippo signaling inhibits GABP transcriptional activity through several mechanisms. In human liver cancers, enhanced YAP expression is correlated with increased nuclear expression of GABP. Therefore, we conclude that GABP is an activator of Yap gene expression and a potential therapeutic target for cancers driven by YAP

Inferring Genetic Variation and Demographic History of Michelia yunnanensis Franch. (Magnoliaceae) from Chloroplast DNA Sequences and Microsatellite Markers

Michelia yunnanensis Franch., is a traditional ornamental, aromatic, and medicinal shrub that endemic to Yunnan Province in southwest China. Although the species has a large distribution pattern and is abundant in Yunnan Province, the populations are dramatically declining because of overexploitation and habitat destruction. Studies on the genetic variation and demography of endemic species are necessary to develop effective conservation and management strategies. To generate such knowledge, we used 3 pairs of universal cpDNA markers and 10 pairs of microsatellite markers to assess the genetic diversity, genetic structure, and demographic history of 7 M. yunnanensis populations. We calculated a total of 88 alleles for 10 polymorphic loci and 10 haplotypes for a combined 2,089 bp of cpDNA. M. yunnanensis populations showed high genetic diversity (Ho = 0.551 for nuclear markers and Hd = 0.471 for cpDNA markers) and low genetic differentiation (FST = 0.058). Geographical structure was not found among M. yunnanensis populations. Genetic distance and geographic distance were not correlated (P > 0.05), which indicated that geographic isolation is not the primary cause of the low genetic differentiation of M. yunnanensis. Additionally, M. yunnanensis populations contracted ~20,000–30,000 years ago, and no recent expansion occurred in current populations. Results indicated that the high genetic diversity of the species and within its populations holds promise for effective genetic resource management and sustainable utilization. Thus, we suggest that the conservation and management of M. yunnanensis should address exotic overexploitation and habitat destruction

Altitudinal Biodiversity Gradient and Ecological Drivers for Different Lifeforms in the Baotianman Nature Reserve of the Eastern Qinling Mountains

Variation in species composition between two communities is so-called β diversity, or dissimilarity, and can be separated into two components: turnover and nestedness. However, the mechanisms underlying these two components remain ambiguous, particularly for different lifeforms. In this study, we examined the altitudinal gradient of biodiversity in the Baotianman Nature Reserve of the eastern Qinling Mountains in central China and found that turnover is the predominant process accounting for β diversity, that dispersal limitation is the main factor influencing species diversity, and that its effect on trees is greater than on shrubs, with herbs least affected. Nestedness, in contrast, is less prominent and generally affected by the richness deviation between communities, and the impact of richness deviation is stronger on shrubs than on trees, and in turn, stronger than on herbs. We zoned the altitudinal vegetation communities by pairwise dissimilarity index, and found that the peak value of turnover rather than β diversity indicates the existence of transitional zones; the higher the turnover index, the greater the diversity between communities. Comparatively, nestedness indicates species overlap between communities. The highest nestedness index usually occurs in the interior of vegetation zones. The result of community clustering by pairwise dissimilarity shows that understory species could have been mostly replaced upwards, while the dominant tree species may keep stable, indicating that dispersal limitation works differently for different lifeforms

FATIGUE DAMAGE ANALYSIS OF VIBRATING SCREEN UPPER BEAM BASED ON STRAIN MODAL ANALYSIS

The displacement and strain modal parameters identification models of the vibrating screen were built based on modal theory,the variations of the displacement and strain modal parameters were analyzed for the vibrating screen upper beam with fatigue damage crack. The results show that the modal frequencies and the displacement mode shapes have no obvious mutation between intact and damaged upper beam,but the strain mode shapes have mutation peaks at the location of the fatigue damage crack,furthermore,the bending strain mode is more sensitive to fatigue damage crack than the twisting strain mode.Thus a fatigue damage indicator is defined by using the strain modal variable ratio between the intact and damaged upper beam,the fatigue crack size is determined by damaged degree of the upper beam,then the residual life of fatigue crack propagation of the upper beam is calculated by the Paris formula of integral form. The predictions of the damaged degree and the fatigue residual life of the vibrating screen upper beam are beneficial to dynamic optimization design,which can improve the service life of the vibrating screen

Identifying Connectivity Conservation Priorities among Protected Areas in Qinling-Daba Mountains, China

Mountain biodiversity is under unprecedented threat due to climate change and excessive human activity. Although protected areas (PAs) are the cornerstone of nature conservation, it is increasingly hard for isolated PAs to maintain the species and ecological processes they depend on in the long term. Linking nature reserves to form a large and connected conservation network is regarded as the optimal measure, but research in this field is lacking in China. We mapped PAs in the Qinling-Daba Mountains in China and identified corridors among PAs and the corridors’ key nodes using a least-cost analysis and circuit theory to model an ecological connectivity conservation network for the region. The results showed that this large ecological network has 46 habitat patches connected by 88 corridors, with 69 pinchpoints, 86 barriers and 37 stepping stones in and around the corridors. In this study, 34.86% of suitable habitats have little or no protection and, in the future, these areas should be developed with caution, with more emphasis on protecting their ecological connectivity. This study used connectivity analysis to construct large ecological corridors based on PAs, providing a framework for connectivity conservation at the biogeographic scale and a scientific reference for further, subsequent conservation actions

The complete chloroplast genome of Castanea sativa Mill. (Fagaceae)

Castanea sativa Mill. is mainly grown in the temperate regions of continental Europe, and it has a considerable economic value. In this study, the complete chloroplast genome sequence of Castanea sativa was characterized. Leaves were collected from the National Botanical Garden of Latvia. The chloroplast genome was determined to be 160,938 bp in length. It contained large single-copy (LSC) and small single-copy (SSC) regions of 90,519 and 18,967 bp, respectively, which were separated by a pair of 25,726 bp inverted repeat (IR) regions. The genome is predicted to contain 130 genes, including 83 protein-coding genes, 37 tRNA genes, eight rRNA genes, and two pseudo genes. The overall GC content of the genome is 36.8%. A phylogenetic tree reconstructed by 34 chloroplast genomes reveals that C. sativa is most closely related to the clade including C. henryi, C. seguinii and C. mollissima