The matrix protein CCN1 (CYR61) promotes proliferation, migration and tube formation of endothelial progenitor cells

Neovascularization and re-endothelialization relies on circulating endothelial progenitor cells (EPCs), but their recruitment and angiogenic roles are subjected to regulation by the vascular microenvironment, which remains largely unknown. The present study was designed to investigate the effects of mature ECs and matrix protein CCN1 on the properties of EPCs. In a coculture system, effects of ECs on proliferation, migration and participation in tube-like formation of EPCs were evaluated, and functional assays were employed to identify the exact role of CCN1 in EPCs vitality and function. We demonstrated that ECs, as an indispensable part of the cellular milieu, significantly promoted the proliferation, migration and tube formation activities of EPCs, and more importantly, CCN1 was potentially involved in such effects of ECs. Expression of CCN1 in EPCs was significantly increased by serum, VEGF, ECs-cocultivation and ECs conditioned medium. Moreover, Ad-CCN1-mediated overexpression of CCN1 directly enhanced migration and tube formation of EPCs, whereas silencing of endogenous CCN1 in EPCs inhibits cell functions. Furthermore, CCN1 induced the expressions of chemokines and growth factors, such as MCP-1 and VEGF, suggesting a complex interaction between those proangiogenic factors. Our data suggest that matrix protein CCN1 may play an important role in microenvironment-mediated biological properties of EPCs.     

Characterization of the oriC region of Mycobacterium smegmatis.

A 3.5-kb DNA fragment containing the dnaA region of Mycobacterium smegmatis has been hypothesized to be the chromosomal origin of replication or oriC (M. Rajagopalan et al., J. Bacteriol. 177:6527-6535, 1995). This region included the rpmH gene, the dnaA gene, and a major portion of the dnaN gene as well as the rpmH-dnaA and dnaA-dnaN intergenic regions. Deletion analyses of this region revealed that a 531-bp DNA fragment from the dnaA-dnaN intergenic region was sufficient to exhibit oriC activity, while a 495-bp fragment from the same region failed to exhibit oriC activity. The oriC activities of plasmids containing the 531-bp sequence was less than the activities of those containing the entire dnaA region, suggesting that the regions flanking the 531-bp sequence stimulated oriC activity. The 531-bp region contained several putative nine-nucleotide DnaA-protein recognition sequences [TT(G/C)TCCACA] and a single 11-nucleotide AT-rich cluster. Replacement of adenine with guanine at position 9 in five of the putative DnaA boxes decreased oriC activity. Mutations at other positions in two of the DnaA boxes also decreased oriC activity. Deletion of the 11-nucleotide AT-rich cluster completely abolished oriC activity. These data indicate that the designated DnaA boxes and the AT-rich cluster of the M. smegmatis dnaA-dnaN intergenic region are essential for oriC activity. We suggest that M. smegmatis oriC replication could involve interactions of the DnaA protein with the putative DnaA boxes as well as with the AT-rich cluster.     

K-77(2)雄性不育小麦花粉壁结构特征

K-77(2)不育花粉内壁比保持系厚将近一倍。在保持系花粉内壁中,有径向排列的、断断续续的、着色深的管状结构。而不育花粉内壁中则没有管状结构,且在不育花粉内壁中形成许多小泡。在花粉粒后期,往往在Z层与内壁连接处断开。推测,由于花粉内壁结构被破坏,影响了正常的营养运输和萌发所需酶的合成而抑制花粉发育。     

Protective effects of irisin on hypoxia-reoxygenation injury in hyperglycemia-treated cardiomyocytes: Role of AMPK pathway and mitochondrial protection

Recent evidence has verified the cardioprotective actions of irisin in different diseases models. However, the beneficial action of irisin on hypoxia-reoxygenation (HR) injury under high glucose stress has not been described. Herein our research investigated the influence of irisin on HR-triggered cardiomyocyte death under high glucose stress. HR model was established in vitro under high glucose treatment. The results illuminated that HR injury augmented apoptotic ratio of cardiomyocyte under high glucose stress; this effect could be abolished by irisin via modulating mitochondrial function. Irisin treatment attenuated cellular redox stress, improved cellular ATP biogenetics, sustained mitochondria potential, and impaired mitochondrion-related cell death. At the molecular levels, irisin treatment activated the 5′-adenosine monophosphate-activated protein kinase (AMPK) pathway and the latter protected cardiomyocyte and mitochondria against HR injury under high glucose stress. Altogether, our results indicated a novel role of irisin in HR-treated cardiomyocyte under high glucose stress. Irisin-activated AMPK pathway and the latter sustained cardiomyocyte viability and mitochondrial function.     

动物对孢子植物的传播模式及进化意义

孢子植物物种多样性丰富, 是自然生态系统的重要组成部分。孢子植物的传播通常被认为主要依靠风、水、弹力等非生物媒介, 而动物的作用往往被忽略。本文主要概述了: (1)孢子植物对动物传播的适应: 一方面孢子植物可为动物提供食物、庇护所、繁殖场所等, 另一方面孢子植物也可产生视觉、嗅觉等方面的线索来吸引动物, 从而促进动物传播其繁殖体。(2)动物对孢子植物的传播模式: 包括体内传播(消化道和组织寄生)和体外传播两种, 这些模式都能对孢子植物繁殖体进行有效传播。由于动物间形态或生活习性的不同, 以致传播距离存在差异, 最短距离为0.1 cm, 最长距离可从北半球至南半球。(3)动物对孢子植物传播的生态与进化意义; 由于某些孢子植物繁殖体的结构特点或萌发的需求, 以致其繁殖体只能通过动物的传播才能得以定殖, 因此动物与孢子植物之间存在密不可分的关系。目前, 动物对孢子植物的传播研究主要是描述性的内容以及研究单方面的传播途径, 建议在今后的研究中考虑动物对孢子植物传播的有效性以及多途径同时传播对孢子植物定殖的影响, 同时应更加关注孢子植物和动物互惠关系的形成、维持机制及将来的进化趋势。     

石蒜属植物的药用和观赏利用前景

石蒜属植物是重要的药用植物,又是一类优良观赏植物,既可用于园林配置,也可用作切花生产或盆栽。综述了石蒜属植物的药用和观赏价值并对其应用前景进行了探讨,为全面开发利用我国这一丰富的野生资源提供了一些理论基础。     

Cathepsin S deficiency results in abnormal accumulation of autophagosomes in macrophages and enhances Ang II-induced cardiac inflammation

Background

Cathepsin S (Cat S) is overexpressed in human atherosclerotic and aneurysmal tissues and may contributes to degradation of extracellular matrix, especially elastin, in inflammatory diseases. We aimed to define the role of Cat S in cardiac inflammation and fibrosis induced by angiotensin II (Ang II) in mice.

Methods and Results

Cat S-knockout (Cat S^−/−) and littermate wild-type (WT) C57BL/6J mice were infused continuously with Ang II (750 ng/kg/min) or saline for 7 days. Cat S^−/− mice showed severe cardiac fibrosis, including elevated expression of collagen I and α-smooth muscle actin (α-SMA), as compared with WT mice. Moreover, macrophage infiltration and expression of inflammatory cytokines (tumor necrosis factor α, transforming growth factor β and interleukin 1β) were significantly greater in Cat S^−/− than WT hearts. These Ang II-induced effects in Cat S^−/− mouse hearts was associated with abnormal accumulation of autophagosomes and reduced clearance of damaged mitochondria, which led to increased levels of reactive oxygen species (ROS) and activation of nuclear factor-kappa B (NF-κB) in macrophages.

Conclusion

Cat S in lysosomes is essential for mitophagy processing in macrophages, deficiency in Cat S can increase damaged mitochondria and elevate ROS levels and NF-κB activity in hypertensive mice, so it regulates cardiac inflammation and fibrosis.     

Diversity of telomere palindromic sequences and replication genes among Streptomyces linear plasmids

Streptomyces sp. linear plasmids and linear chromosomes usually contain conserved terminal palindromic sequences bound by the conserved telomeric proteins Tap and Tp, encoded by the tap and tpg genes, respectively, as well as plasmid loci required for DNA replication in circular mode when the telomeres are deleted. These consist of iterons and an adjacent rep gene. By using PCR, we found that 8 of 17 newly detected linear plasmids in Streptomyces strains lack typical telomeric tap and tpg sequences. Instead, two novel telomeres in plasmids pRL1 and pRL2 from the eight strains and one conserved telomere in pFRL1 from the other strains were identified, while multiple short palindromes were also found in the plasmids. The complete nucleotide sequence of pRL2 revealed a gene encoding a protein containing two domains, resembling Tap of Streptomyces and a helicase of Thiobacillus, and an adjacent gene encoding a protein similar to Tpg of Streptomyces and a portion of the telomere terminal protein pTP of adenoviruses. No typical iterons-rep loci were found in the three plasmids. These results indicate an unexpected diversity of telomere palindromic sequences and replication genes among Streptomyces linear plasmids.