Roles of a sustained activation of NCED3 and the synergistic regulation of ABA biosynthesis and catabolism in ABA signal production in Arabidopsis

ABA, acting as a stress signal, plays crucial roles in plant resistance to water stress. Because ABA signal production is based on ABA biosynthesis, the regulation of NCED, a key enzyme in the ABA biosynthesis pathway, is normally thought of as the sole factor controlling ABA signal production. Here we demonstrate that ABA catabolism in combination with a synergistic regulation of ABA biosynthesis plays a crucial role in governing ABA signal production. Water stress induced a significant accumulation of ABA, which exhibited different patterns in detached and attached leaves. ABA catabolism followed a temporal trend of exponential decay for both basic and stress ABA, and there was little difference in the catabolic half-lives of basic ABA and stress ABA. Thus, the absolute rate of ABA catabolism, i.e. the amount of ABA catabolized per unit time, increases with increased ABA accumulation. From the dynamic processes of ABA biosynthesis and catabolism, it can be inferred that stress ABA accumulation may be governed by a synergistic regulation of all the steps in the ABA biosynthesis pathway. Moreover, to maintain an elevated level of stress ABA sustained activation of NCED3 should be required. This inference was supported by further findings that the genes encoding major enzymes in the ABA biosynthesis pathway, e.g. NCED3, AAO3 and ABA3 were all activated by water stress, and with ABA accumulation progressing, the expressions of NCED3, AAO3 and ABA3 remained activated. Data on ABA catabolism and gene expression jointly indicate that ABA signal production is controlled by a sustained activation of NCED3 and the synergistic regulation of ABA biosynthesis and catabolism.     

PELP1 protein and the estrogen non-genomic signaling pathway

Estrogen exerts its biological effects through two signal pathways,the genomic and non-genomic pathway,both of which contribute to cell homeostasis.The non-genomic pathway has been suggested to be important in estrogen-induced cardio-,neuron-,and osteoprotection,and confers the ability of the cell to rapidly respond to its environment.The effects of the non-genomic pathway are the regulation of different cellular processes,such as proliferation,survival,apoptosis,and other functions in diverse cell-types.The proline-,glutamic acid-,and leucine-rich protein 1(PELP1),is now known as a modulator of the estrogen receptors,and is also a novel coregulator of the non-genomic signal pathway with various functions.Therefore,the evaluation of the molecular crosstalk between PELP1 and the non-genomic pathway may lead to the development of functionally selective estrogen receptor modulators which can participate in the multiple functions of estrogen signaling in reproductive tissues and other organs.     

Exploration on ecological regulation of the reservoirs

Reservoir regulation process in the Yangtze River basin is mainly divided into two types of flood regulation and initiating benefit regulation. The present reservoir management system and operation mode are mainly for dealing with or coordinating of flood control and benefit initiation as well as benefit distribution among various beneficial functions. From the view point of river ecosystem protection, the current regulation mode has two kinds of problems ： firstly, most of the reservoir regulation plans do not consider ecosystem protection at downstream of dams and needs of environment protection in reservoir areas; secondly, integrated regulation or management of water resources is ignored. It is very necessary to improve reservoir regulation mode, bearing problems faced by regulation of the Three Gorges reservoir and issues related to cascade development and regulation in Tuojiang and Minjiang River basins in mind. In accordance with the concept of scientific development, and the philosophy of ＂ensuring a healthy Yangtze River and promoting the harmony between human and water＂, taking flood control, benefit initiation and eco-system as a whole, this paper put forward the basic consideration to improve reservoir regulation as follows ： on the basis of requirements of ecosystem protection at downstream of dams and needs of environment protection in reservoir areas, we should bring the functions of reservoir such as flood control and benefit initiation into full play, control the negative influence to the ecosystem at downstream of dams and the environment in reservoir areas in an endurable scope, and restore the ecosystem and the environment step by step. This paper put forward the relevant regulation process aiming at the idiographic problems such as protection of ecosystem at downstream of dams and environment in reservoir areas, protection of aquatic wildlife species and fish species, regulation of sediment and protection of wetland.     

Localization of NOS-like protein in guard cells of Vicia faba L. and its possible function

Using the immuno-fluorescence and immuno-gold electron microscope technology, localization of ni- tric oxide synthase (NOS)-like proteins was determined in guard cells of Vicia faba L. NOS is mainly localized in nucleus, cytoplasm, chloroplast, mitochondria and the cell wall of guard cells. Scorch and exogenous JA can enhance the level of nitric oxide (NO) and increase NOS activity in both leaf and epidermis, and the changing pattern of NOS activity was consistent with the change of NO. NOS in- hibitor, L-NAME, inhibited JA-induced NO generation. From the results, we presumed that NO genera- tion from NOS pathway is the main pathway in the stress and JA responses. The pharmacological ex- periment showed that increasing the Ca2 at a suitable concentration promoted leaf NOS activity and the NO level, indicating that NOS activity together with the distribution of NO is Ca2 -dependent. NOS and NO are possibly involved in the regulation of stomatal movement thus playing an important role in plant stress responses.     

Roles of protein kinase C in oocyte meiotic maturation and fertilization

Protein kinase C (PKC) is a superfamily of Ser/Thr protein kinases that is distributed widely in eukaryotes. It plays key regulatory roles at multiple steps of oocyte meiotic maturation and fertilization. During the process of meiotic maturation, the activation of PKC in cumulus cells stimulates meiotic maturation, whereas the activation of PKC in oocytes results in the inhibition of germinal vesicle breakdown. PKC activity increases following the meiotic maturation, and decreases at the transition of metaphase/anaphase in meiosis I, so as to facilitate the release of the first polar body and the entry of meiosis II. In fertilization of mammalian oocytes, PKC may act as one of the downstream targets of Ca2+ to stimulate the cortical granule exocytosis, release the oocytes from MII arrest and to induce pronucleus formation. PKC is also involved in the regulation of maturation promoting factor (MPF) and mitogen-activated protein kinase (MAPK). Several PKC isoforms have been identified in mammalian oocytes, and there is evidence showing that classical PKCs may be the principal mediator of oocyte cortical reaction.     

Inhibitors of protein kinase C

Protein kinase catalyzes the transfer of the γ-phosphoryl group from ATP to the hydroxyl groups o fprotein side chains, which plays critical roles in signal transduction pathways by transmitting extracellular signals across the plasma membrane and nuclear membrane to the destination sites in the cytoplasm and the nucleus. Protein kinase C (PKC) is a superfamily of phospholipid-dependent Ser/Thr kinase. There are at least 12 isozymes in PKC family.They are distributed in different tissues and play different roles in physiological processes. On account of their concern with a variety of pathophysiologic states, such as cancer,inflammatory conditions, autoimmune disorder, and cardiac diseases, the inhibitors, which can inhibit the activity of PKC and the interaction of cytokine with receptor, and interfere signal transduction pathway, may be candidates of therapeutic drugs. Therefore, intense efforts have been made to develop specific protein kinase inhibitors as biological tools and therapeutic agents. This article reviews the recent development of some of PKC inhibitors based on their interaction with different conserved domains and different inhibition mechanisms.     

Phenotypic and Functional Analysis of Porcine T Lymphocytes

IntroductionPorcine is a useful model for the heterogeneity ofmammalian immune systems and has also receivedattention as a possible source of organs for humantransplants[1] .T lymphocytes are an importantcomponent of immune cells which directly inducecellular immune response and play a key role inimmune regulation.The cognition,activation,andfunction of T lymphocytes depend on interactionsbetween T cells and antigen presenting cells,aswell as B lymphocytes and other cells.The basesfor the in…     

Cell adhesion receptors and cancer

Cell-to-cell and cell-to-extracellular matrix (ECM) interactions in the functions of cell adhesion and signal transduction are important in global control of cell phenotypes and cell behavior and are crucial for maintenance of homeostasis and structural/functional stabilization of tissues and organs. Cell adhesion receptors are recognized as the molecular basis of cell adhesion. Cadherin and Integrin are widely expressed adhesion receptors in most tissues. They are transmembrane glycoproteins which, through their cytoplasmic domain, bind to many proteins at the inner surface of cell membrane to form molecule-linkage complexes and then connect with the cytoskeleton. Through cell adhesion receptors a network functioning as cell adhesion and signal transduction is organized between tissue cells and cell-ECM. In this regard cell adhesion receptors play an important role in regulation of morphogenesis, cell-cell recognition, cell migration, cell sorting and the determination of cell's fate in development. They mediate cell functions and their fault expression is intimately correlated with development of disorders like cancer. Several isoforms of Integrin were found to have tumor suppressor effect. Some components in the molecule-linkage of focal contact are actin-binding proteins as well as substrates of kinase in the Integrin initiated signal pathway to play a role as signal transducer. Some of these molecules exhibited tumor suppressor effect too. Decreased expression of E-Cadherin has been demonstrated in many epithelium originated carcinomas. Cadherin associated membrane adhesion plaque molecule β-Catenin is also involved in the oncogene Wnt signal pathway. Both E-Cadherin and β-Catenin were proved respectively with tumor suppressor effect against invasiveness and metastasis. That Cadherin is important for the posttranslationally functional expression of Connexin has been supported by evidence from developmental biology and cancer cell differentiation studies to suggest that some sort of interrelation feedback control exists between the two signal pathways.     

Expression pattern of GASA,downstream genes of DELLA,in Arabidopsis

Separation and functional research of related components involved in gibberellins （GAs） signaling are important to clarify the mechanism of GA functioning. Research on the downstream components of DELLA, the key factor of the GA signaling pathway, is limited at present. GASA （GA-Stimulated in Arabidopsis） family contains 15 genes usually regulated by GA in Arabidopsis thaliana. All GASA proteins have a cleavable signal peptide in N terminus and a conserved GASA domain including 12 cysteines in C terminus. RT-PCR analysis revealed that the expression of GASA4 and GASA6 were down-regulated, but GASA 1 and GASA9 were up-regulated in the DELLA mutants, gai-t6 and rga-24, as well as the double mutant, consisting with the results that GASA4 and GASA6 were induced, but GASA1 and GASA9 were inhibited by exogenous GA3. In addition, the expression patterns of other GASA genes were regulated by GA and ABA, separately or cooperatively. Most of GASA genes were expressed in roots, stems, leaves, flowers and developing siliques. GUS gene driven by the promoters of GASA6, GASA7, GASA8, GASA9, GASAIO, GASA11 and GASA12were used as reporters and it was found that all GASA genes expressed in the growing and differentiating organs and abscission zones, suggesting the role of these genes in cell growth and differentiation. This study provided an important basis for functional study of the GASA gene family in the GA and ABA signaling pathway.     

An in-situ DRIFTS study in the reaction between NO x and soot on BaAl2O4

The interactions between NO, O2 and their mixture on BaAl2O4, as well as the reaction of NOx with soot in the presence of O2, have been investigated using Diffuse Reflectance Infrared Fourier Transform Spectroscopy （DRIFTS）. NO adsorption produces only nitrites species in the absence of O2. NO2 adsorption produces nitrates species besides nitrites species. The produced nitrites will further react with O2, Osurf^-. and Olattice^2- to form nitrates. The reaction of NOx with soot begins with the reaction of nitrates with soot oxygenated complex （C（O））, which is regarded as the key and rate determining step. A reaction pathway is proposed for the catalyzed reaction of NOx with soot in the presence of O2.     

Roles of MAP kinase signaling pathway in oocyte meiosis

Mitogen-activated protein kinase (MAPK) is a family of Ser/Thr protein kinases expressed widely in eukaryotic cells. MAPK is activated by a cascade of protein kinase phosphorylation and plays pivotal roles in regulating meiosis process in oocytes. As an important physical substrate of MAPK, p90^rsk mediates numerous MAPK functions. MAPK was activated at G2/M transition during meiosis. Its activity reached the peak at MⅠ stage and maintained at this level until the time before the pronuclear formation after fertilization. There is complex interplay between MAPK and MPF in the meiosis regulation. Furthermore, other intracellular signal transducers, such as cAMP, protein kinase C and protein phosphotase, ect., also regulated the activity of MAPK at different stages during meiosis in oocytes. In the present article, the roles of MAPK signaling pathway in oocyte meiosis are reviewed and discussed.     

Recent advances in fermentative biohydrogen production

Hydrogen energy, as a kind of clean energy with great potential, has been a hotspot for study worldwide. Based on the recent research on biohydrogen production, this paper gives a brief review on the following aspects： fermentative hydrogen production process and the engineering control statagy, key factors affecting the efficiency of hydrogen production, such as substrates, cysteine, metal ions, anaerobic fermentation terminal products, and formic acid and ammonia. Moreover, anaerobic fermentative hydrogen-producing strain and regulation and control of enzyme gene in fermentative hydrogen production are also discussed. Finally, the prospect of anaerobic fermentative biohydrogen production is proposed in three study areas, namely developing new techniques for breeding hydrogen-producing bacteria, exploitations of more strains and gene resources, and intensifying the application of microbial molecular breeding in hydrogen production.     

An in-situ DRIFTS study in the reaction between NO_x and soot on BaAl_2O_4

The interactions between NO, O2 and their mixture on BaAl2O4, as well as the reaction of NOx with soot in the presence of O2, have been investigated using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). NO adsorption produces only nitrites species in the absence of O2. NO2 ad- sorption produces nitrates species besides nitrites species. The produced nitrites will further react with O2, O-su rf and O l2-att ice to form nitrates. The reaction of NOx with soot begins with the reaction of ni- trates with soot oxygenated complex (C(O)), which is regarded as the key and rate determining step. A reaction pathway is proposed for the catalyzed reaction of NOx with soot in the presence of O2.     

Contributions of DPOR at Low Light Intensi.ty to Chlorophyll Biosynthesis and Growth in the Synechocystis sp. PCC 6803

Introduction Chlorophylls (Chls) and bacteriochlorophylls (Bchls) are two of the most abundant classes of natural pigments, and their biosynthesis is a major metabolic activity in the ecosystem[1]. Protochlorophyllide (Pchlide) is an intermediate in the Chl and Bchl biosynthetic pathway of photosynthetic organisms and its reduction to chlorophyllide (Chlide) is a key regulatory step in the Chl biosynthesis pathway. In this reaction, the porphyrin D-ring of Pchlide is converted to chlorin b…