硼营养与植物细胞壁关系的研究进展

植物必需的７种微量元素中,植物缺硼最为普遍,因而引起人们的广泛关注。半个多世纪以来,学者们对硼的生理功能和硼肥应用进行了广泛的研究,为农业生产作出了重大贡献。但由于硼元素的特殊性,至今对硼在植物体内的存在形式和基本生理功能仍不十分清楚。不同植物的缺硼症状尽管各不相同,但一个显著的共同特征就是根尖和茎尖的伸长首先受到抑制。顶端生长依赖于细胞分裂和细胞伸长,由此可见,硼必然首先影响分生组织的细胞分裂和细胞伸长。硼对细胞分裂的影响已进行了大量的研究。Ｗｈｉｔｔｉｎｇｔｏｎ〔１〕曾报道缺硼减少大豆有丝分…     

苏北滨海湿地麋鹿恢复种群的研究

1986年至2004年,在苏北滨海湿地开展恢复麋鹿野生种群的研究。从每年的2月份开始,在麋鹿的产仔期按照每旬记录产仔数,直至产仔结束。逐年统计半散养和野生麋鹿种群结构。选择不同年龄阶段和不同性别的麋鹿进行称重,分析个体的身体发育程度。半散养麋鹿种群由1986年引进的39 头,发展到2004年的706 头,年均出生率21.7%,鹿群年均增长率为17.5%,现已繁殖了子四代;野生放养麋鹿由31 头增加到2004年的41头,年均出生率16.3%,年均增长率为9.0% ,且于2003年、2004年各产1 头完全属野生的子二代。产仔季节相由引进时的紊乱已调整至目前的规律性产仔。研究表明大丰麋鹿种群繁殖很成功,其寿命、行为、生理发育、繁殖周期等都较引进时发生了显著的变化,已完全适应了黄海湿地生态环境。人类活动干扰仍是影响麋鹿种群恢复的一个重要因素。     

LMP1 Increases Expression of NADPH Oxidase (NOX) and Its Regulatory Subunit p22 in NP69 Nasopharyngeal Cells and Makes Them Sensitive to a Treatment by a NOX Inhibitor

Oxidative stress is thought to contribute to cancer development. Epstein–Barr virus (EBV) and its encoded oncoprotein, latent membrane protein 1 (LMP1), are closely associated with the transformation of nasopharyngeal carcinoma (NPC) and Burkitt’s lymphoma (BL). In this study, we used LMP1-transformed NP cells and EBV-related malignant cell lines to assess the effects of LMP1 on reactive oxygen species (ROS) accumulation and glycolytic activity. Using NPC tissue samples and a tissue array to address clinical implications, we report that LMP1 activates NAD(P)H oxidases to generate excessive amount of ROS in EBV-related malignant diseases. By evaluating NAD(P)H oxidase (NOX) subunit expression, we found that the expression of the NAD(P)H oxidase regulatory subunit p22^phox was significantly upregulated upon LMP1-induced transformation. Furthermore, this upregulation was mediated by the c-Jun N-terminal kinase (JNK) pathway. In addition, LMP1 markedly stimulated anaerobic glycolytic activity through the PI3K/Akt pathway. Additionally, in both NPC cells and tissue samples, p22^phox expression correlated with LMP1 expression. The NAD(P)H oxidase inhibitor diphenyleneiodonium (DPI) also exerted a marked cytotoxic effect in LMP1-transformed and malignant cells, providing a novel strategy for anticancer therapy.     

Assembly of dandelion-like Au/PANI nanocomposites and their application as SERS nanosensors

The monodisperse, uniform dandelion-like Au/polyaniline (PANI) composite nanospheres were synthesized by a simple one-step process without any additives or templates. The nanospheres are really composed of many short nanorods and the average diameter of whole nanospheres is about 180 nm. The morphology of Au/PANI composites could be controlled by adjusting the molar ratio of HAuCl(4) to aniline. The prepared nanocomposite is developed as a wonderful sensor for the detection of Hg(2+) ions, which is based upon the Raman intensity response of PANI to Hg(2+) ions. Results from the morphology-dependent sensitivity investigations show that the dandelion-like nanospheres have an ultra sensitive response (as low as 10(-11)M) compared with other morphologies. The nanosensor also exhibits good reproducibility and greater selectivity for Hg(2+) ions than the other heavy metal ions. And the mechanism was proposed. The proposed nanosensors can be applied for highly sensitive and selective chemical analysis in a variety of environmental detection.     

Role of HLA-G and NCR in protection of umbilical cord blood haematopoietic stem cells from NK cell mediated cytotoxicity

Allogeneic umbilical cord blood haematopoietic stem cells (UCB-HSCs) can be transplanted into a host with the intact innate immunity with limited immuno-reaction, although the mechanisms remain unclear. The present studies aimed at investigating potential mechanisms of allogeneic UCB-HSCs escape from the cytolysis of natural killer (NK) cells. We compared UCB-HSCs ability to protect from NK-mediated cytotoxicity with peripheral blood or bone marrow haematopoietic stem cells (PB-HSCs and BM-HSCs). HSCs expressed lower levels of natural cytotoxicity receptor ligands including NKp30L, NKp44L and NKp46L than monocytes. Blocking these ligands respectively or in combination could increase the resistance of HSCs against NK cell mediated cytotoxicity. High expression of HLA-G was noticed on UCB-HSCs, rather than PB-HSCs or BM-HSCs, whereas blockade of HLA-G significantly elevated NK cell mediated cytolysis to UCB-HSCs. Thus, we conclude that natural cytotoxicity receptors and HLA-G on HSCs may contribute to the escape from NK cells, and activate and inhibitory NK cell receptors and their ligands can be novel therapeutic targets in cell transplantation.     

Integrative identification of Arabidopsis mitochondrial proteome and its function exploitation through protein interaction network

Mitochondria are major players on the production of energy, and host several key reactions involved in basic metabolism and biosynthesis of essential molecules. Currently, the majority of nucleus-encoded mitochondrial proteins are unknown even for model plant Arabidopsis. We reported a computational framework for predicting Arabidopsis mitochondrial proteins based on a probabilistic model, called Naive Bayesian Network, which integrates disparate genomic data generated from eight bioinformatics tools, multiple orthologous mappings, protein domain properties and co-expression patterns using 1,027 microarray profiles. Through this approach, we predicted 2,311 candidate mitochondrial proteins with 84.67% accuracy and 2.53% FPR performances. Together with those experimental confirmed proteins, 2,585 mitochondria proteins (named CoreMitoP) were identified, we explored those proteins with unknown functions based on protein-protein interaction network (PIN) and annotated novel functions for 26.65% CoreMitoP proteins. Moreover, we found newly predicted mitochondrial proteins embedded in particular subnetworks of the PIN, mainly functioning in response to diverse environmental stresses, like salt, draught, cold, and wound etc. Candidate mitochondrial proteins involved in those physiological acitivites provide useful targets for further investigation. Assigned functions also provide comprehensive information for Arabidopsis mitochondrial proteome.     

Global gene expression profiling of endothelium exposed to heme reveals an organ-specific induction of cytoprotective enzymes in sickle cell disease

Background

Sickle cell disease (SCD) is characterized by hemolysis, vaso-occlusion and ischemia reperfusion injury. These events cause endothelial dysfunction and vasculopathies in multiple systems. However, the lack of atherosclerotic lesions has led to the idea that there are adaptive mechanisms that protect the endothelium from major vascular insults in SCD patients. The molecular bases for this phenomenon are poorly defined. This study was designed to identify the global profile of genes induced by heme in the endothelium, and assess expression of the heme-inducible cytoprotective enzymes in major organs impacted by SCD.

Methods and Findings

Total RNA isolated from heme-treated endothelial monolayers was screened with the Affymetrix U133 Plus 2.0 chip, and the microarray data analyzed using multiple bioinformatics software. Hierarchical cluster analysis of significantly differentially expressed genes successfully segregated heme and vehicle-treated endothelium. Validation studies showed that the induction of cytoprotective enzymes by heme was influenced by the origin of endothelial cells, the duration of treatment, as well as the magnitude of induction of individual enzymes. In agreement with these heterogeneities, we found that induction of two major Nrf2-regulated cytoprotective enzymes, heme oxygenase-1 and NAD(P)H:quinone oxidoreductase-1 is organ-specific in two transgenic mouse models of SCD. This data was confirmed in the endothelium of post-mortem lung tissues of SCD patients.

Conclusions

Individual organ systems induce unique profiles of cytoprotective enzymes to neutralize heme in SCD. Understanding this heterogeneity may help to develop effective therapies to manage vasculopathies of individual systems.