RBP differentiation contributes to selective transmissibility of OPT3 mRNAs

Long-distance mobile mRNAs play key roles in gene regulatory networks that control plant development and stress tolerance. However, the mechanisms underlying species-specific delivery of mRNA still need to be elucidated. Here, the use of grafts involving highly heterozygous apple (Malus) genotypes allowed us to demonstrate that apple (Malus domestica) oligopeptide transporter3 (MdOPT3) mRNA can be transported over a long distance, from the leaf to the root, to regulate iron uptake; however, the mRNA of Arabidopsis (Arabidopsis thaliana) oligopeptide transporter 3 (AtOPT3), the MdOPT3 homolog from A. thaliana, does not move from shoot to root. Reciprocal heterologous expression of the two types of mRNAs showed that the immobile AtOPT3 became mobile and moved from the shoot to the root in two woody species, Malus and Populus, while the mobile MdOPT3 became immobile in two herbaceous species, A. thaliana and tomato (Solanum lycopersicum). Furthermore, we demonstrated that the different transmissibility of OPT3 in A. thaliana and Malus might be caused by divergence in RNA-binding proteins between herbaceous and woody plants. This study provides insights into mechanisms underlying differences in mRNA mobility and validates the important physiological functions associated with this process.

The long-distance movement of OPT3 is selective between herbaceous and woody plants as shown using Malus and Arabidopsis thaliana plants.     

单纯疱疹病毒2型潜伏相关转录体ORF1的表达及其抗凋亡作用

旨在研究单纯疱疹病毒2型潜伏相关转录体 (LAT) 开放读码框1 (ORF1) 对放线菌素D诱导的凋亡作用的影响。以HSV-2 333基因组为模板PCR扩增ORF1片段,构建重组质粒pEGFP-ORF1,转染Vero细胞,RT-PCR鉴定ORF1的表达。放线菌素D诱导Vero细胞凋亡,通过荧光显微镜观察凋亡小体,Hochest33258荧光染色观察细胞形态变化,MTT检测细胞活性,流式细胞术检测细胞凋亡率。双酶切和测序确认pEGFP-ORF1构建成功,RT-PCR表明该真核表达载体能在Vero细胞中高效表达。转染了pEGFP-ORF1的Vero细胞经放线菌素D凋亡诱导后,Hochest33258染色显示细胞形态正常。MTT结果表明转染了重组质粒pEGFP-ORF1的Vero细胞经放线菌素D凋亡诱导后Vero细胞活性与未经任何处理的正常对照组相比,无显著差异 (P＞0.05),但高于放线菌素D诱导凋亡的Vero细胞组及与转染空质粒pEGFP-C2且放线菌素D诱导凋亡的Vero细胞组,差异具有统计学意义 (P＜0.05)。流式结果表明,转染重组质粒pEGFP-ORF1且经放线菌素D诱导凋亡组与正常对照组凋亡率差异不显著 (P＞0.05),而显著低于放线菌素D诱导凋亡组和转染空质粒pEGFP-C2且经放线菌素D诱导凋亡组 (P＜0.05)。HSV-2 LAT ORF1具有抗放线菌素D诱导的Vero细胞的凋亡作用。     

基于线粒体COI基因全序列的直翅目部分类群系统发育关系分析

该研究基于直翅目56种昆虫的COI基因全序列构建了该目部分类群间的系统发育关系,同时也分析了COI基因编码的氨基酸序列构建直翅目系统发育关系的可靠性。将COI序列按照密码子一、二、三位点划分,分别计算PBS(partioned Bremer support)值,评估蛋白质编码基因密码子不同位点的系统发生信号强度。分析结果支持螽亚目和蝗亚目的单系性;剑角蝗科、斑腿蝗科、斑翅蝗科、网翅蝗科和槌角蝗科5科均不是单系群,科间的遗传距离在0.107~0.153之间变化,与其他科相比遗传距离较小,符合将这5科合并为一科(即蝗科)的分类系统,瘤锥蝗科和锥头蝗科归为锥头蝗总科,癞蝗科单独成为一科,这也与Otte(1997)系统的划分一致。根据PBS值的大小推断密码子第三、第一位点对系统树分支的贡献比第二位点大,并且较长的序列含有较多的信息位点。研究也证实将各物种COI基因之间的遗传距离作为直翅目划分科级阶元的工具是可行的。     

Resveratrol protects H9c2 embryonic rat heart derived cells from oxidative stress by inducing autophagy: role of p38 mitogen-activated protein kinase

Recently, many studies have attempted to illustrate the mechanism of autophagy in protection against oxidative stress to the heart induced by H(2)O(2). However, whether resveratrol-induced autophagy involves the p38 mitogen-activated protein kinase (MAPK) pathway is still unknown. This study aimed to investigate whether treating H9c2 cells with resveratrol increases autophagy and attenuates the cell death and apoptosis induced by oxidative stress via the p38 MAPK pathway. Resveratrol with or without SB202190, an inhibitor of the p38 MAPK pathway, was added 30 min before H(2)O(2). After H(2)O(2) treatment, the cells were incubated under 5% CO(2) at 37 °C for 24 h to assess cell survival and death or incubated for 20 min for Western blot and transmission electron microscopy. Flow cytometry was used to detect apoptosis after 6 h of H(2)O(2) treatment. Resveratrol at 20 μmol/L protected H9c2 cells treated with 100 μmol/L H(2)O(2) from oxidative damage. It increased cell survival and markedly decrease lactate dehydrogenase release. In addition, resveratrol increased autophagy and decreased H(2)O(2)-induced apoptosis. Furthermore, the protective effects of resveratrol were inhibited by 10 μmol/L SB202190. Thus, resveratrol protected H(2)O(2)-treated H9c2 cells by upregulating autophagy via the p38 MAPK pathway.     

Dissection of human MiRNA regulatory influence to subpathway

The global insight into the relationships between miRNAs and their regulatory influences remains poorly understood. And most of complex diseases may be attributed to certain local areas of pathway (subpathway) instead of the entire pathway. Here, we reviewed the studies on miRNA regulations to pathways and constructed a bipartite miRNAs and subpathways network for systematic analyzing the miRNA regulatory influences to subpathways. We found that a small fraction of miRNAs were global regulators, environmental information processing pathways were preferentially regulated by miRNAs, and miRNAs had synergistic effect on regulating group of subpathways with similar function. Integrating the disease states of miRNAs, we also found that disease miRNAs regulated more subpathways than nondisease miRNAs, and for all miRNAs, the number of regulated subpathways was not in proportion to the number of the related diseases. Therefore, the study not only provided a global view on the relationships among disease, miRNA and subpathway, but also uncovered the function aspects of miRNA regulations and potential pathogenesis of complex diseases. A web server to query, visualize and download for all the data can be freely accessed at http://bioinfo.hrbmu.edu.cn/miR2Subpath.     

Recognition of H3K9me1 by maize RNA-directed DNA methylation factor SHH2

RNA-directed DNA methylation (RdDM) is a plant-specific de novo DNA methylation pathway, which has extensive cross-talk with histone modifications. Here, we report that the maize RdDM regulator SAWADEE HOMEODOMAIN HOMOLOG 2 (SHH2) is an H3K9me1 reader. Our structural studies reveal that H3K9me1 recognition is achieved by recognition of the methyl group via a classic aromatic cage and hydrogen-bonding and salt-bridge interactions with the free protons of the mono-methyllysine. The di- and tri-methylation states disrupt the polar interactions, decreasing the binding affinity. Our study reveals a mono-methyllysine recognition mechanism which potentially links RdDM to H3K9me1 in maize.     

Apoplastic hydrogen peroxide and superoxide anion exhibited different regulatory functions in salt-induced oxidative stress in wheat leaves

The present work aimed to investigate the mechanisms of nitric oxide (NO) and reactive oxygen species (ROS) generations and to explore their roles in the regulation of antioxidative responses in the wheat leaves under salinity. Except for an insignificant change of NO content and nitrate reductase (NR) activity due to 50 mM NaCl, NO, hydrogen peroxide, superoxide anion (O₂^?-), hydroxyl radical (?OH), chlorophyll and malondialdehyde content, as well as activities of nitric oxide synthase, NR, peroxidases (POD), catalase (CAT), and ascorbate peroxidase rose in response to different NaCl concentrations. Meanwhile, leaf superoxide dismutase activity lowered only at 50 mM NaCl. NaCl-stimulatory effects on NO content as well as POD and CAT activities could be partly alleviated by the application of 2-phenyl-4,4,5,5-tetrame-thylimidazoline-3-oxide-1-oxyl (PTIO, NO scavenger), exogenous CAT, or diphenylene iodonium (DPI, NADPH oxidase inhibitor). Native polyacrylamide gel electrophoresis also showed that the amount of POD (especially POD4, POD5, and POD7) and CAT (especially CAT1, CAT2, and CAT3) isozymes increased with increasing salinity but decreased by application of PTIO, CAT, or DPI. Furthermore, histochemical staining showed a similar change of O₂^?- generation. In addition, the inhibition of diamineoxidase (DAO), polyamine oxidase (PAO), and cell wall-bound POD (cw-POD) activities in NaCl-stressed seedlings seemed to be insensitive to the application of PTIO or DPI. Taken together, salinity-induced NO, H₂O₂, and O₂^?- generation influenced each other and played different roles in the regulation of antioxidant enzyme activities in the leaves of wheat seedlings under NaCl treatment.     

北京城市与西北远郊地表臭氧浓度梯度移动监测研究

北京城市与区域臭氧浓度逐年升高,对自然生态系统已经构成影响。但地表臭氧在北京城市与远郊梯度空间上的连续递变特征机制尚不清楚。采用移动监测车,搭载臭氧分析仪,选择夏季典型臭氧污染天气,以北京教学植物园为对照点,从北京城市中心向西北远郊方向,多点位连续测定地表臭氧浓度。通过分析臭氧浓度和采样点周围归一化植被指数(NDVI)的关系以及典型臭氧污染情况下的天气形势和气团轨迹,探讨北京城市和区域臭氧浓度连续空间变化特征及机制。结果表明:(1)北京西北山区森林区域臭氧浓度显著高于"城市区域",约为城市区域的2.00倍。十三陵是地表臭氧浓度的分界点,从十三陵开始臭氧浓度陡然升高,在西北山区方向保持在高水平。空间上从高到低的顺序是西北山区(254.68μg/m~3)对照点教学植物园(220.89μg/m~3)城市支路(162.84μg/m~3)城市快速路和高速路(103.24μg/m~3);(2)植被分布影响臭氧空间格局。在相同时间范围内,臭氧浓度和NDVI正相关,随NDVI增加臭氧浓度呈Logistic增长;(3)西北山区地表臭氧空间变异系数为0.11,城市支路上平均为0.28,城市快速路上为0.26,高速公路上为0.36。山区地表臭氧浓度的空间变异系数最小,高速公路最大,城市快速路、城市支路空间变异较大;(4)大范围均压场、高压后部、低压前部等稳定型天气型易造成南向弱气流,能够把空气污染物输送到西北远郊,但本研究中监测到的西北山区高浓度臭氧并非当天从城区输送而来。北京城市与区域臭氧格局与植被的关系及成因需要深入研究。     

ROCK1 induces ERK nuclear translocation in PDGF-BB-stimulated migration of rat vascular smooth muscle cells

It has been known that Rho-associated protein kinase (ROCK) signaling regulates the migration of vascular smooth muscle cells (VSMCs). However, the isoform-specific roles of ROCK and its underlying mechanism in VSMC migration are not well understood. The current study thus aimed to investigate the roles of ROCK1/2 and their relationship to the MAPK signaling pathway in platelet-derived growth factor (PDGF)-induced rat aorta VSMC migration by manipulating ROCK gene expression. The results revealed that ROCK1 small interfering ribonucleic acid (siRNA) rather than ROCK2 siRNA decreased PDGF-BB-generated VSMC migration, and upregulation of ROCK1 expression via transfection of constructed pEGFP-C1/ROCK1 plasmid further increased the migration of PDGF-BB-treated VSMCs. In PDGF-treated VSMCs, ROCK1 siRNA did not affect the phosphorylation levels of ERK and p38 in the cytoplasm, but decreased the level of ERK phosphorylation in the nucleus. These findings demonstrate that activated ROCK1 can promote VSMC migration through facilitating phosphorylation and nuclear translocation of ERK protein.