Molecular phylogeny and species delimitation of Stachyuraceae: Advocating a herbarium specimen‐based phylogenomic approach in resolving species boundaries

Species concept and delimitation are fundamental to taxonomic and evolutionary studies. Both inadequate informative sites in the molecular data and limited taxon sampling have often led to poor phylogenetic resolution and incorrect species delineation. Recently, the whole chloroplast genome sequences from extensive herbarium specimen samples have been shown to be effective to amend the problem. Stachyuraceae are a small family consisting of only one genus Stachyurus of six to 16 species. However, species delimitation in Stachyurus has been highly controversial because of few and generally unstable morphological characters used for classification. In this study, we sampled 69 individuals of seven species (each with at least three individuals) covering the entire taxonomic diversity, geographic range, and morphological variation of Stachyurus from herbarium specimens for genome‐wide plastid gene sequencing to address species delineation in the genus. We obtained high‐quality DNAs from specimens using a recently developed DNA reconstruction technique. We first assembled four whole chloroplast genome sequences. Based on the chloroplast genome and one nuclear ribosomal DNA sequence of Stachyurus, we designed primers for multiplex polymerase chain reaction and high throughput sequencing of 44 plastid loci for species of Stachyurus. Data of these chloroplast DNA and nuclear ribosomal DNA internal transcribed spacer sequences were used for phylogenetic analyses. The phylogenetic results showed that the Japanese species Stachyurus praecox Siebold & Zucc. was sister to the rest in mainland China, which indicated a typical Sino‐Japanese distribution pattern. Based on diagnostic morphological characters, distinct distributional range, and monophyly of each clade, we redefined seven species for Stachyurus following an integrative species concept, and revised the taxonomy of the family based on previous reports and specimens, in particular the type specimens. Furthermore, our divergence time estimation results suggested that Stachyuraceae split from its sister group Crossosomataceae from the New World at ca. 54.29 Mya, but extant species of Stachyuraceae started their diversification only recently at ca. 6.85 Mya. Diversification time of Stachyurus in mainland China was estimated to be ca. 4.45 Mya. This research has provided an example of using the herbarium specimen‐based phylogenomic approach in resolving species boundaries in a taxonomically difficult genus.     

全反式维甲酸对骺软骨细胞生物学行为及其功能影响的研究

该研究主要探讨了体外高浓度全反式维甲酸(all-trans retinoic acid,ATRA)对SD大鼠骺软骨细胞生物学性状和功能的影响以及体内ATRA对SD大鼠胫骨生长板的影响。以SD大鼠骺软骨细胞为研究对象、ATRA为干预因素,采用CCK-8、细胞流式术、HE染色、Annexin V-FITC细胞凋亡流式检测术、Hoechst染色、细胞划痕、Transwell实验分别评估ATRA处理后细胞的增殖、周期、形态、凋亡及迁移情况,Western blot检测蛋白聚糖、Ⅱ型胶原、X型胶原等相关功能蛋白的变化;以3周雄性SD大鼠为实验对象,分为对照组、60 mg/kg·d ATRA组、80 mg/kg·d ATRA组,进行10天连续ATRA灌胃处理,测量每只SD大鼠灌胃第1天、第10天的头尾长,处理10天后对胫骨生长板进行HE染色。结果表明,ATRA作用SD大鼠骺软骨细胞后,增殖能力减弱且细胞周期被阻滞在S期(P<0.01),细胞形态由三角形、多边形变为长条状,凋亡的发生增多(P<0.01),迁移能力受到抑制(P<0.05)以及Western blot结果显示蛋白聚糖、Ⅱ型胶原、X型胶原等功能相关蛋白较对照组表达均明显降低(P<0.01);对SD大鼠进行ATRA灌胃处理后,与对照组比较,60 mg/kg·d ATRA组和80 mg/kg·d ATRA组的头尾长均变短(P<0.01);胫骨生长板HE染色显示,ATRA灌胃组的生长板变窄甚至闭合。该研究证实了体外高浓度ATRA能够对SD大鼠骺软骨细胞的增殖、迁移起抑制作用,同时能够诱导凋亡,降低相关功能蛋白的表达,在SD大鼠体内证实,过量ATRA可影响生长板软骨内成骨过程,最终使生长板部分或全部提前闭合,进而影响SD大鼠身长的增长。     

Alpine grassland plants grow earlier and faster but biomass remains unchanged over 35 years of climate change

Satellite data indicate significant advancement in alpine spring phenology over decades of climate warming, but corresponding field evidence is scarce. It is also unknown whether this advancement results from an earlier shift of phenological events, or enhancement of plant growth under unchanged phenological pattern. By analyzing a 35‐year dataset of seasonal biomass dynamics of a Tibetan alpine grassland, we show that climate change promoted both earlier phenology and faster growth, without changing annual biomass production. Biomass production increased in spring due to a warming‐induced earlier onset of plant growth, but decreased in autumn due mainly to increased water stress. Plants grew faster but the fast‐growing period shortened during the mid‐growing season. These findings provide the first in situ evidence of long‐term changes in growth patterns in alpine grassland plant communities, and suggest that earlier phenology and faster growth will jointly contribute to plant growth in a warming climate.     

Increased miR‐34c mediates synaptic deficits by targeting synaptotagmin 1 through ROS‐JNK‐p53 pathway in Alzheimer’s Disease

Alzheimer's disease (AD) and cancer have inverse relationship in many aspects. Some tumor suppressors, including miR‐34c, are decreased in cancer but increased in AD. The upstream regulatory pathways and the downstream mechanisms of miR‐34c in AD remain to be investigated. The expression of miR‐34c was detected by RT–qPCR in oxidative stressed neurons, hippocampus of SAMP8 mice, or serum of patients with amnestic mild cognitive impairment (aMCI). Dual luciferase assay was performed to confirm the binding sites of miR‐34c in its target mRNA. The Morris water maze (MWM) was used to evaluate learning and memory in SAMP8 mice administrated with miR‐34c antagomir (AM34c). Golgi staining was used to evaluate the synaptic function and structure. The dramatically increased miR‐34c was mediated by ROS‐JNK‐p53 pathway and negatively regulated synaptotagmin 1 (SYT1) expression by targeting the 3′‐untranslated region (3′‐UTR) of syt1 in AD. The expression of SYT1 protein was reduced by over expression of miR‐34c in the HT‐22 cells and vice versa. Administration of AM34c by the third ventricle injection or intranasal delivery markedly increased the brain levels of SYT1 and ameliorated the cognitive function in SAMP8 mice. The serum miR‐34c was significantly increased in patients with aMCI and might be a predictive biomarker for diagnosis of aMCI. These results indicated that increased miR‐34c mediated synaptic and memory deficits by targeting SYT1 through ROS‐JNK‐p53 pathway and the miR‐34c/SYT1 pathway could be considered as a promising novel therapeutic target for patients with AD.     

Structure and Properties of Organogels Developed by Diosgenin in Canola Oil

Food Biophysics - In this study, naturally occurring ingredient diosgenin was utilized as an organogelator for structuring canola oil. Results show that stable diosgenin-based organogel can be...     

Nimbolide prevents myocardial damage by regulating cardiac biomarkers,antioxidant level,and apoptosis signaling against doxorubicin‐induced cardiotoxicity in rats

The current work planned to assess the protecting properties of nimbolide against doxorubicin (DOX)‐treated myocardial damage. Myocardial damage was produced with 2.5 mg/kg of DOX given on alternative days (14 days). Thiobarbituric acid reactive substances (TBARS) levels of a lipid peroxidative marker were elevated, whereas reduced body weight, heart weight, blood pressure indices and reduced levels of antioxidants like glutathione‐S‐transferase, superoxide dismutase, catalase, glutathione peroxidase, glutathione, and glutathione reductase were observed in the heart tissue of DOX‐treated animals. DOX‐treated animals showed augmented levels of cardiac markers likes monocyte chemotactic protein‐1, interferon‐gamma, aspartate transferase, creatine kinase, lactate dehydrogenase, creatine kinase‐muscle/brain, heart‐type fatty acid‐binding protein, glycogen phosphorylase isoenzyme BB, transforming growth factor‐β, brain natriuretic peptide, myoglobin, and cTnI in serum. Histopathological assessment confirmed the DOX‐induced cardiotoxicity. Furthermore, DOX‐induced rats showed augmented inflammatory mediators (nuclear factor‐κB [NF‐kB], tumor necrosis factor‐α [TNF‐α], and interleukin‐1β [IL‐1β]) and increased PI3K/Akt signaling proteins (PI3K, p‐Bad/Bad, caspase‐3, and p‐Akt), whereas decreased oxidative markers (HO‐1 and NQO‐1) and p‐PTEN were observed. Nimbolide‐supplemented rats showed reduced activity/levels of cardiac markers and TBARS levels in serum and heart tissue. Levels of enzymatic and nonenzymatic antioxidants were augmented in the heart tissue of nimbolide‐supplemented rats. Nimbolide influence decreased apoptosis, inflammation, and enhanced antioxidant markers through the modulation of p‐Bad/Bad, caspase‐3, PI3K, p‐Akt, TNF‐α, NF‐kB, IL‐1β, HO‐1, NQO‐1, and p‐PTEN markers. The histopathological explanations were observed to be in line with biochemical analysis. Therefore, the finding of current work was that nimbolide has a defensive effect on the myocardium against DOX‐induced cardiac tissue damage.