Protein phosphatases: properties and role in cellular regulation

Protein phosphorylation is a principal regulatory mechanism in the control of almost all cellular processes. The nature of the protein phosphatases that participate in these reactions has been a subject of controversy. Four enzymes, termed protein phosphatases 1, 2A, 2B, and 2C, account for virtually all of the phosphatase activity toward phosphoproteins involved in controlling glycogen metabolism, glycolysis, gluconeogenesis, fatty acid synthesis, cholesterol synthesis, and protein synthesis. The properties, physiological roles, and mechanisms for regulating the four protein phosphatases are reviewed.     

Extracellular DNA plays a key role in deep-sea ecosystem functioning

The ecological role and biogeochemical relevance of extracellular DNA in the oceanic sediments are unknown. Our global estimates indicate that up to 0.45 gigatons of extracellular DNA are present in the top 10 centimeters of deep-sea sediments, representing the largest reservoir of DNA in the world oceans. We demonstrate that extracellular DNA accounts for about one fifth of the total organic phosphorus regeneration and provides almost half of the prokaryotic demand for organic phosphorus. It therefore plays a key role in deep-sea ecosystem functioning on a global scale.     

UHRF1 plays a role in maintaining DNA methylation in mammalian cells

Epigenetic inheritance in mammals relies in part on robust propagation of DNA methylation patterns throughout development. We show that the protein UHRF1 (ubiquitin-like, containing PHD and RING finger domains 1), also known as NP95 in mouse and ICBP90 in human, is required for maintaining DNA methylation. UHRF1 colocalizes with the maintenance DNA methyltransferase protein DNMT1 throughout S phase. UHRF1 appears to tether DNMT1 to chromatin through its direct interaction with DNMT1. Furthermore UHRF1 contains a methyl DNA binding domain, the SRA (SET and RING associated) domain, that shows strong preferential binding to hemimethylated CG sites, the physiological substrate for DNMT1. These data suggest that UHRF1 may help recruit DNMT1 to hemimethylated DNA to facilitate faithful maintenance of DNA methylation.     

Functions of sphingolipids and sphingolipid breakdown products in cellular regulation

The discovery that breakdown products of cellular sphingolipids are biologically active has generated interest in the role of these molecules in cell physiology and pathology. Sphingolipid breakdown products, sphingosine and lysosphingolipids, inhibit protein kinase C, a pivotal enzyme in cell regulation and signal transduction. Sphingolipids and lysosphingolipids affect significant cellular responses and exhibit antitumor promoter activities in various mammalian cells. These molecules may function as endogenous modulators of cell function and possibly as second messengers.     

The peroxisomal matrix shuttling receptor Pex5 plays a role in FB1 production and virulence in Fusarium verticillioides

The peroxisomal matrix oxidase,catalase and peroxidase are imported peroxisomes through the shuttling receptors,which regulates the cellular oxidative homeostasis and function.Here,we report that PTS1 shuttling receptor FvPex5 is involved in the localization of PTS1,utilization of carbon sources and lipids,elimination ROS,cell wall stress,conidiation,fumonisin B₁(FB₁) production,and virulence in maize pathogen Fusarium verticillioides.Significantly,differential expression o...     

Brain calcium: role in temperature regulation

Perfusion of the preoptic-anterior hypothalamus with excess calcium ion in ground squirrels produces a drop in core temperature. The magnitude of the drop is directly dependent on ambient temperature. Respiration, heart rate, and oxygen consumption are also reduced during perfusion of calcium ion. It is concluded that the depression of body temperature during calcium ion perfusion is due to generalized depression of the neurons of the preoptic-anterior hypothalamus.     

猕猴桃钙调蛋白cDNA的克隆及测序

以“秦美”猕猴桃果实呼吸跃变初期ｃＤＮＡ第一链为模板，参考大麦钙调蛋白基因序列合成５′端和３′端引物，利用多聚酶链式反应（ＰＣＲ）合成了完整的猕猴桃钙调蛋白ｃＤＮＡ，克隆并测定了其全序列。结果表明，猕猴桃钙调蛋白基因读码框架内序列由４４４个核苷酸组成，共编码１４８个氨基酸，且与植物领域里发表的大麦及苜蓿的钙调蛋白基因有很高的同源性。在核苷酸序列上与大麦有８６．１６％的同源性，与苜蓿有８５．６９％的同源性，其编码的氨基酸与大麦和苜蓿的不同分别只是一个氨基酸的差异，同源率高达９９．３％．     

钙、钙调蛋白与植物的有性生殖

钙、钙调蛋白作为信号转导因子，在植物生长发育过程中起着十分重要的作用，在植物有性生殖过程中，钙，钙调蛋白的分布也发生一系列的变化，综述了植物有性生殖过程中的动态，并介绍了一些广泛运用于钙，钙调蛋白研究的方法。     

The technology path to deep greenhouse gas emissions cuts by 2050: the pivotal role of electricity

Several states and countries have adopted targets for deep reductions in greenhouse gas emissions by 2050, but there has been little physically realistic modeling of the energy and economic transformations required. We analyzed the infrastructure and technology path required to meet California's goal of an 80% reduction below 1990 levels, using detailed modeling of infrastructure stocks, resource constraints, and electricity system operability. We found that technically feasible levels of energy efficiency and decarbonized energy supply alone are not sufficient; widespread electrification of transportation and other sectors is required. Decarbonized electricity would become the dominant form of energy supply, posing challenges and opportunities for economic growth and climate policy. This transformation demands technologies that are not yet commercialized, as well as coordination of investment, technology development, and infrastructure deployment.     

狗枣猕猴桃钙调节蛋白基因生物信息学分析

通过NCBI查找到狗枣猕猴桃钙调节蛋白基因序列,利用生物信息学方法对该基因编码蛋白的理化性质、二维结构、三维结构、糖基化位点、所属蛋白家族、代谢途径、进化地位等信息进行了预测。结果表明,该蛋白富含天冬氨酸和谷氨酸,不含N-糖基化位点和O-糖基化位点,属于EF-hand蛋白家族,在钙信号、cAMP信号转导及植物与病原菌的相互作用、细胞减数分裂等过程中均有重要作用。     

红花miR397a基因表达及对靶基因LAC2的调控作用

【目的】研究红花miR397a前体基因及成熟基因在红花不同组织中的表达水平,并对miR397a基因序列、靶基因及基因功能进行分析,为深入研究红花抗逆机制提供参考。【方法】提取红花籽粒、花瓣、茎、根、叶片等5个组织材料的总RNA,使用荧光定量PCR鉴定miR397a在不同组织中的表达水平;利用生物信息学方法分析红花miR397a基因序列,用原生质体转化方法验证红花miR397a调控的靶基因LAC2,并利用转基因拟南芥表型研究miR397a基因的功能。【结果】miR397a前体基因和成熟基因均能在红花不同组织中表达,且均以叶片组织中的表达量最高,分别是籽粒组织的2.5与1.9倍,差异达极显著水平;miR397a序列在不同物种间高度保守,序列中仅存在1~2个碱基的错配或缺失;miR397a对LAC2基因有调控作用,miR397a的过表达可引起LAC2表达水平降低,红花miR397a表达引起植物对NaCl的敏感性增加。【结论】红花miR397a在叶片组织中的表达量最高,基因序列保守,且红花miR397a表达可增强植物对NaCl的敏感性。     

Tomato SlPti5 plays a regulative role in the plant immune response against Botrytis cinerea through modulation of ROS system and hormone pathways

While SlPti5 has been shown to play a crucial role in the regulation of antagonistic genes in Solanum lycopersicum and Arabidopsis against pathogen infection, there have been no comprehensive studies on the effects of SlPti5 on the regulatory response mechanism of reactive oxygen species(ROS) system and hormone pathways during growth and disease resistance of tomato plants. Here, we investigated the function of SlPti5 in the defense response of tomato against Botrytis cinerea utilizing a virus-i...     

Crayfish muscle receptor organ: role in regulation of postural flexion

Recordings were made from postural-control motor nerves with antagonistic functions in the crayfish abdomen through flexible suction electrodes. During unrestrained flexion of the abdomen, output from the tonic stretch receptor neuron of RM(1),(SR(1)) is sufficient to drive an extensor motor unit in the same segment. However, this intrasegmental "resistance" reflex is normally blocked by an intersegmental reflex in which output from SR(1)'s in caudal segments inhibits SR(1) discharge in more anterior segments.     

Insulin-like growth factors: a role in growth hormone negative feedback and body weight regulation via brain

Intracerebroventricular administration of ILA's, a preparation enriched in insulin-like growth factors, caused a marked decrease in growth hormone secretory episodes and in body weight associated with reduced food intake over 24 hours. Central injection of insulin and bovine serum albumin had no such effects. These findings suggest that insulin-like growth factors play a role in growth hormone negative feedback and body weight regulation at the level of the central nervous system.     

Beneficial roles silicon plays in agriculture

正Silicon(Si),asecondmostabundantelementinsoil,is nonessential but beneficial for higher plants.Silicon addition can result in improved plant growth, yield and quality.Indeed, application of Si fertilizer is a rather common agricultural practice in many countries and regions, especially in Southeast Asian countries.Despite that numerous research outcomes show the beneficial roles Si plays in providing     

A role for histone acetylation in the developmental regulation of VDJ recombination

VDJ recombination is developmentally regulated in vivo by enhancer-dependent changes in the accessibility of chromosomal recombination signal sequences to the recombinase, but the molecular nature of these changes is unknown. Here histone H3 acetylation was measured along versions of a transgenic VDJ recombination reporter and the endogenous T cell receptor alpha/delta locus. Enhancer activity was shown to impart long-range, developmentally regulated changes in H3 acetylation, and H3 acetylation status was tightly linked to VDJ recombination. H3 hyperacetylation is proposed as a molecular mechanism coupling enhancer activity to accessibility for VDJ recombination.