固氮螺菌的固氮分子调控研究进展

本文对巴西固氮螺菌周氨基因的结构和调控进行综述。其固氮基因的调控可分为两种水平：通过DRAT-DRAG系统的翻译后水平和通过NifA蛋白的转录水平。通过NifA活性进行调控的机理目前尚不明了。     

Regulation of equine infectious anemia virus expression

Equine infectious anemia virus (EIAV) is an ungulate lentivirus that is related to human immunodeficiency virus (HIV). Much of the understanding of lentiviral gene regulation comes from studies using HIV. HIV studies have provided insights into molecular regulation of EIAV expression; however, much of the regulation of EIAV expression stands in stark contrast to that of HIV. This review provides an overview of the current state of knowledge of EIAV regulation by comparing and contrasting EIAV gene regulation to HIV. The role of EIAV gene regulation is discussed in relation to EIAV pathogenesis.     

MnSOD基因表达调控的研究进展

MnSOD是生物体内重要的氧自由基清除剂, 具有抗氧化和抗肿瘤作用。MnSOD基因的表达调控是一个复杂的过程, 多种转录因子、细胞信号分子和细胞信号通路参与其中。MnSOD基因的表达调控包括转录调控、转录后调控和翻译调控3个方面。转录调控是MnSOD基因表达调控的第一个层次, 在MnSOD基因表达的过程中起重要作用。它主要是通过调节与MnSOD基因转录相关的转录因子活性来实现的, 例如特异蛋白-1 (SP-1)、激活蛋白-2(AP-2)、激活蛋白-1(AP-1)、核因子-卡巴B(NF-κB)等。药物和金属离子就是通过改变这些转录因子的活性来调控MnSOD基因表达的, 另外某些基因的突变和缺失也能改变这些转录因子的活性。转录后调控主要体现在改变mRNA的稳定性或mRNA的翻译上。翻译调控则是对MnSOD多肽的编辑、修饰并与相应的金属离子结合及定位的调控。近年来发现了一种线粒体MnSOD的锰转运因子, 它对MnSOD活性的调控起重要作用。文章综述了这一研究领域的一些进展, 着重讨论了MnSOD基因的转录调控和翻译调控, 并展望了MnSOD基因表达调控的研究方向。     

Effect of P(II) and its homolog GlnK on reversible ADP-ribosylation of dinitrogenase reductase by heterologous expression of the Rhodospirillum rubrum dinitrogenase reductase ADP-ribosyl transferase-dinitrogenase reductase-activating glycohydrolase regulatory system in Klebsiella pneumoniae

Reversible ADP-ribosylation of dinitrogenase reductase, catalyzed by the dinitrogenase reductase ADP-ribosyl transferase-dinitrogenase reductase-activating glycohydrolase (DRAT-DRAG) regulatory system, has been characterized in Rhodospirillum rubrum and other nitrogen-fixing bacteria. To investigate the mechanisms for the regulation of DRAT and DRAG activities, we studied the heterologous expression of R. rubrum draTG in Klebsiella pneumoniae glnB and glnK mutants. In K. pneumoniae wild type, the regulation of both DRAT and DRAG activity appears to be comparable to that seen in R. rubrum. However, the regulation of both DRAT and DRAG activities is altered in a glnB background. Some DRAT escapes regulation and becomes active under N-limiting conditions. The regulation of DRAG activity is also altered in a glnB mutant, with DRAG being inactivated more slowly in response to NH4+ treatment than is seen in wild type, resulting in a high residual nitrogenase activity. In a glnK background, the regulation of DRAT activity is similar to that seen in wild type. However, the regulation of DRAG activity is completely abolished in the glnK mutant; DRAG remains active even after NH4+ addition, so there is no loss of nitrogenase activity. The results with this heterologous expression system have implications for DRAT-DRAG regulation in R. rubrum.     

微生物细胞工厂的代谢调控

代谢调控是构建微生物细胞工厂的重要技术手段.随着合成生物学技术的不断突破,挖掘和人工设计的高质量调控元件大幅度提升了对细胞代谢网络的改造能力;代谢调控研究也已从单基因的静态调控发展到系统水平上的智能精确动态调控.文中简要综述了近30年来代谢途径表达调控技术在代谢工程领域的研究进展.     

The temporal dynamics of voluntary emotion regulation

Background

Neuroimaging has demonstrated that voluntary emotion regulation is effective in reducing amygdala activation to aversive stimuli during regulation. However, to date little is known about the sustainability of these neural effects once active emotion regulation has been terminated.

Methodology/Principal Findings

We addressed this issue by means of functional magnetic resonance imaging (fMRI) in healthy female subjects. We performed an active emotion regulation task using aversive visual scenes (task 1) and a subsequent passive viewing task using the same stimuli (task 2). Here we demonstrate not only a significantly reduced amygdala activation during active regulation but also a sustained regulation effect on the amygdala in the subsequent passive viewing task. This effect was related to an immediate increase of amygdala signal in task 1 once active emotion regulation has been terminated: The larger this peak postregulation signal in the amygdala in task 1, the smaller the sustained regulation effect in task 2.

Conclusions/Significance

In summary, we found clear evidence that effects of voluntary emotion regulation extend beyond the period of active regulation. These findings are of importance for the understanding of emotion regulation in general, for disorders of emotion regulation and for psychotherapeutic interventions.     

The role of protein kinase CK2 in the regulation of the insulin production of pancreatic islets

An appropriate regulation of the insulin production and secretion in pancreatic β-cells is necessary for the control of blood glucose homeostasis. The pancreatic duodenal homeobox factor-1 (Pdx-1) is among the various factors and signals which are implicated in the regulation of the insulin synthesis and secretion in the pancreatic β-cells. Recently, we identified Pdx-1 as a substrate for protein kinase CK2. Since CK2 is implicated in the regulation of many different cellular signaling pathways we now asked whether it might also be involved in the regulation of the insulin regulation in β-cells. Here, we show that insulin treatment of β-cells resulted in an elevated CK2 kinase activity. On the other hand down-regulation of CK2 activity by quinalizarin led to an elevated level of insulin. These results demonstrate that CK2 is implicated in the insulin regulation on pancreatic β-cells.     

我国公立医院规制策略失效现况及影响因素因子分析

?????? 目的 探讨医院规制的主要失效关键节点及导致规制效果不佳的主要因素。方法 采用文献研究及专题小组讨论法,构建医院规制框架;通过调查研究分析医院规制失效主要内容;运用因子分析法分析规制效果不佳的主要因素。结果 确立了包括准入、价格等10项规制措施的医院整体规制框架,其失效程度最严重的为价格规制、行为规制及补偿规制,导致规制整体效果不佳的公因子为监管体制、条件等行政支持因子与监管执行的障碍因子2项。结论 构建医院规制体系,明确各措施的失效程度,提出导致规制效果不佳的公因子,为今后医院规制研究与政策制定提供参考依据。     

论我国现代医院管理制度中的运行监管与行业监管策略

作为现代医院外部管理制度的主要组成部分,现代医院监管制度的建立对于现代医院管理制度的建立健全具有重要意义。现代医院监管制度可分为运行监管和行业监管两类,文章在对运行监管和行业监管的概念进行界定的基础上,分析了我国医院监管的现存问题,最后提出了运行监管和行业监管的完善策略,为现代医院监管制度的建立提供理论参考。     

Identification of a cytoplasmic Tyr-X-X-Leu motif essential for down regulation of the human cell receptor CD46 in persistent measles virus infection.

To investigate the sequence requirements for measles virus (MV)-induced receptor down regulation, we transfected the human CD46 gene into simian cells persistently infected by the Biken strain of MV. Surface expression of CD46 is drastically reduced in these cells. Deletion analysis has shown that the juxtamembrane region of the CD46 cytoplasmic domain is essential for down regulation. Deleting a Tyr-Arg-Tyr-Leu sequence in this region or changing these residues to Ala prevents CD46 down regulation from the infected cell surface. Alanine-scanning mutagenesis has identified two amino acid residues, Tyr and Leu, forming a Tyr-X-X-Leu motif critical for CD46 down regulation. Mutations that prevent CD46 down regulation enhance syncytium formation. These results indicate that CD46 down regulation limits the cytopathic effects in a persistent MV infection and that CD46 down regulation requires a cytoplasmic Tyr-X-X-Leu sequence which resembles known motifs for membrane protein trafficking and receptor signalling.     

Chromatin regulation of flowering

The transition to flowering is a major developmental switch in the life cycle of plants. In Arabidopsis (Arabidopsis thaliana), chromatin mechanisms play critical roles in flowering-time regulation through the expression control of key flowering-regulatory genes. Various conserved chromatin modifiers, plant-specific factors, and long noncoding RNAs are involved in chromatin regulation of FLOWERING LOCUS C (FLC, a potent floral repressor). The well-studied FLC regulation has provided a paradigm for chromatin-based control of other developmental genes. In addition, chromatin modification plays an important role in the regulation of FLOWERING LOCUS T (FT, encoding florigen), which is widely conserved in angiosperm species. The chromatin mechanisms underlying FT regulation in Arabidopsis are likely involved in the regulation of FT relatives and, therefore, flowering-time control in other plants.     

Evolution of glutamate dehydrogenase regulation of insulin homeostasis is an example of molecular exaptation

Glutamate dehydrogenase (GDH) is found in all organisms and catalyzes the oxidative deamination of glutamate to 2-oxoglutarate. While this enzyme does not exhibit allosteric regulation in plants, bacteria, or fungi, its activity is tightly controlled by a number of compounds in mammals. We have previously shown that this regulation plays an important role in insulin homeostasis in humans and evolved concomitantly with a 48-residue "antenna" structure. As shown here, the antenna and some of the allosteric regulation first appears in the Ciliates. This primitive regulation is mediated by fatty acids and likely reflects the gradual movement of fatty acid oxidation from the peroxisomes to the mitochondria as the Ciliates evolved away from plants, fungi, and other protists. Mutagenesis studies where the antenna is deleted support this contention by demonstrating that the antenna is essential for fatty acid regulation. When the antenna from the Ciliates is spliced onto human GDH, it was found to fully communicate all aspects of mammalian regulation. Therefore, we propose that glutamate dehydrogenase regulation of insulin secretion is a example of exaptation at the molecular level where the antenna and associated fatty acid regulation was created to accommodate the changes in organelle function in the Ciliates and then later used to link amino acid catabolism and/or regulation of intracellular glutamate/glutamine levels in the pancreatic beta cells with insulin homeostasis in mammals.     

Dimensions of Affect Modulated by Perceived Mood Regulation Ability

The ability to regulate mood is a facet of emotional intelligence that may contribute to an individual’s physical and mental health. Precisely what is regulated when mood regulation occurs is dependent on what “makes up” mood. The purpose of this study was to evaluate whether perceived mood regulation ability can predict regulation of affect during task engagement and whether affect regulation is specific to valence or arousal. Measures of positive affect, negative affect, and frontal area sEMG (as a measure of arousal) were obtained from a sample of one hundred twenty-four participants categorized by their self report as possessing low or high mood regulation ability. Modulation of positive affect, but not negative affect, was predicted by perceived mood regulation ability. The results of sEMG were mixed. These data provide some support for the hypothesis that mood regulation ability can predict future efforts to regulate affect, at least in the context of task engagement.     

Hierarchical and metabolic regulation of glucose influx in starved Saccharomyces cerevisiae

A novel method dissecting the regulation of a cellular function into direct metabolic regulation and hierarchical (e.g., gene-expression) regulation is applied to yeast starved for nitrogen or carbon. Upon nitrogen starvation glucose influx is down-regulated hierarchically. Upon carbon starvation it is down-regulated both metabolically and hierarchically. The method is expounded in terms of its implications for diverse types of regulation. It is also fine-tuned for cases where isoenzymes catalyze the flux through a single metabolic step.     

Environmental regulation and CO2 emissions: Based on strategic interaction of environmental governance

In order to reduce carbon emissions and improve environmental governance, the paper discusses the interactive forms of environmental regulation based on the two-regime spatial Durbin model. The effects of environmental regulation and interactive behavior of environmental regulation on carbon dioxide (CO₂) emissions are explored by using the spatial lag of X (SLX) model. It is found that there is a diversified competitive behavior in the enforcement of environmental regulation among local governments in China. And the diversified competitive behavior results in the nearby transfer of pollution, which increases local CO₂ emissions. In addition, there is an inverted "U" curve between environmental regulation and CO₂ emissions, and China is still in the "green paradox" stage. Furthermore, it is found that the environmental regulation mainly affects CO₂ emissions through industrial structure and technological progress. Also, there are differences in the spatial spillover effect of environmental regulation due to the existence of regional heterogeneity, and its impact on CO₂ is particularly significant in the western region. The findings indicate that the central government should strengthen targeted supervision and adaptive incentives for local governments to implement environmental regulation so that joint emission reduction can be promoted.     

Serotonin regulates C. elegans fat and feeding through independent molecular mechanisms

We investigated serotonin signaling in C. elegans as a paradigm for neural regulation of energy balance and found that serotonergic regulation of fat is molecularly distinct from feeding regulation. Serotonergic feeding regulation is mediated by receptors whose functions are not required for fat regulation. Serotonergic fat regulation is dependent on a neurally expressed channel and a G protein-coupled receptor that initiate signaling cascades that ultimately promote lipid breakdown at peripheral sites of fat storage. In turn, intermediates of lipid metabolism generated in the periphery modulate feeding behavior. These findings suggest that, as in mammals, C. elegans feeding behavior is regulated by extrinsic and intrinsic cues. Moreover, obesity and thinness are not solely determined by feeding behavior. Rather, feeding behavior and fat metabolism are coordinated but independent responses of the nervous system to the perception of nutrient availability.