Home About us Contact
|
Home About us Contact | ||
|
|
||
Cyclic Adenosine (cyclic + adenosine)
Terms modified by Cyclic Adenosine Selected AbstractsModeling the model organism Dictyostelium discoideumDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 6 2000Seido Nagano The cellular slime mold Dictyostelium discoideum is a fascinating organism, not only for biologists, but also for physicists. Since the Belousov,Zhabotinskii reaction pattern, a well-known non-linear phenomenon in chemistry, was observed during aggregation of Dictyostelium amoebae, Dictyostelium has been one of the major subjects of non-linear dynamics studies. Macroscopic theory, such as continuous cell density approximation, has been a common approach to studying pattern formation since the pioneering work of Turing. Recently, promising microscopic approaches, such as the cellular dynamics method, have emerged. They have shown that Dictyostelium is useful as a model system in biology. The synchronization mechanism of oscillatory production of cyclic adenosine 3,,5,-monophosphate in Dictyostelium is discussed in detail to show how it is a universal feature that can explain synchronization in other organisms. [source] Fluorescent, molecularly imprinted thin-layer films based on a common polymer,JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Piotr Cywinski Abstract Fluorescent, molecularly imprinted polymer thin films, with cyclic guanosine 3,,5,-monophosphate (cGMP) as a template and 1,2-diphenyl-6-vinyl-1H -pyrazole-[3,4- b]-quinoline as a fluorescent receptor, were prepared according to a method based on commercially available poly (methyl methacrylate). This method of preparation predicts photoinduced crosslinking in the mixture of polymer chains and involved components. The advantages of this method are the relative simplicity of its preparation and the fact that a common polymer can be used. The spin-coated thin-layer films of imprinted and nonimprinted polymers were studied with the use of fluorescence microscopy with a scanning range of 80 × 80 ,m. A strong fluorescence quenching effect was observed when a cGMP-imprinted film was incubated in aqueous solutions of cGMP, but a comparatively small effect was observed for a nonimprinted polymer and when an imprinted film was incubated with cyclic adenosine 3,,5,-monophosphate (cAMP). The separation factor by the imprinted polymer was determined to be 2.55 for cGMP against cAMP. The obtained polymeric sensor appeared to be stable during subsequent measurements after rewashing and readsorption. The homogeneity of the surface of the polymer film, dependent on the method of film preparation, was also studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 229,235, 2007 [source] Identification of a Parathyroid Hormone in the Fish Fugu rubripes,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2003Janine A Danks Abstract A PTH gene has been isolated from the fish Fugu rubripes. The encoded protein of 80 amino acid has the lowest homology with any of the PTH family members. Fugu PTH(1,34) had 5-fold lower potency than human PTH(1,34) in a mammalian cell system. Introduction: Parathyroid hormone (PTH) is the major hypercalcemic hormone in higher vertebrates. Fish lack parathyroid glands, but there have numerous attempts to identify and isolate PTH from fish. Materials and Methods: Polymerase chain reaction (PCR) was performed with primers based on preliminary data from the Joint Genome Institute database. PCR amplification was performed on genomic DNA isolated from Fugu rubripes. PCR products were purified and DNA was sequenced. All sequence was confirmed from more than one independently amplified PCR product. Multiple sequence alignments were carried out, and the percentage of identities and similarities were calculated. An unrooted phylogenetic tree, using all the known PTH and PTH-related protein (PTHrP) amino acid sequences, was determined. Synthetic peptides were tested in a biological assay that measured cyclic adenosine 3,,5,-monophosphate formation in UMR106.1 cells. Rabbit polyclonal antisera specific for N-terminal human PTHrP and one rabbit polyclonal antiserum specific for N terminus hPTH were used to test the cross-reactivity with fPTH(1,34) in immunoblots. [source] Overexpression of RGPR-p117 enhances regucalcin gene promoter activity in cloned normal rat kidney proximal tubular epithelial cells: Involvement of TTGGC motifJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2006Natsumi Sawada Abstract A novel protein RGPR-p117 was discovered as regucalcin gene promoter region-related protein that binds to the TTGGC motif using a yeast one-hybrid system. RGPR-p117 is localized in the nucleus of kidney cells, and overexpression of RGPR-p117 can modulate regucalcin protein and its mRNA expression in the cloned normal rat kidney proximal tubular epithelial NRK52E cells. This study was undertaken to determine whether overexpression of RGPR-p117 enhances the regucalcin promoter activity using the ,710/+18 LUC construct (wild-type) or ,710/+18 LUC construct (mutant) with deletion of ,523/,435 including TTGGC motif. NRK52E cells (wild-type) or stable HA-RGPR-p117/phCMV2-transfected cells (transfectant) were cultured in Dulbecco's minimum essential medium (DMEM) containing 5% bovine serum (BS). Wild-type cells or transfectants were transfected with the ,710/+18 LUC construct vector or the ,710/+18 LUC construct with deletion of ,523/,435. Wild-type cells or transfectants with subconfluency were cultured for 48 h in a DMEM medium containing either vehicle, BS (5%), or parathyroid hormone (1,34) (PTH; 10,7 M). Luciferase activity in wild-type cells was significantly increased with culture of BS or PTH. This increase was significantly blocked in the presence of various protein kinase inhibitors (staurosporine and PD 98059). Luciferase activity in transfectants was significantly increased as compared with that of wild-type cells in the absence of BS or PTH. The increase in luciferase activity in transfectants was completely decreased in mutant with deletion of ,523/,435 sequence of regucalcin promoter. This was also seen using the ,710/+18 LUC construct with deletion of ,523/,503 sequence containing TTGGC motif. The increase in luciferase activity in transfectants was not significantly enhanced with culture of BS (5%), PTH (10,7 M), Bay K 8644 (10,6 M), phorbol 12-myristate 13-acetate (PMA; 10,6 M), or N6, 2,-dibutyryl cyclic adenosine 3,, 5,-monophosphate (DcAMP; 10,4 M). The increase in luciferase activity in transfectants was completely inhibited with culture of dibucaine (10,6 M), staurosporine (10,9 M), PD 98059 (10,8 M), wortmannin (10,8 M), genistein (10,6 M), vanadate (10,6 M), or okadaic acid (10,6 M) which are inhibitors of various kinases and protein phosphatases. This study demonstrates that RGPR-p117 can enhance the regucalcin promoter activity which is related to the NF-1 consensus sequences including TTGGC motif, and that its enhancing effect is partly mediated through phosphorylation and dephosphorylation in NRK52E cells. J. Cell. Biochem. 99: 589,597, 2006. © 2006 Wiley-Liss, Inc. [source] Cyclic nucleotide phosphodiesterases and their role in immunomodulatory responses: Advances in the development of specific phosphodiesterase inhibitorsMEDICINAL RESEARCH REVIEWS, Issue 2 2005Ana Castro Abstract The activity of phosphodiesterases (PDEs) is associated with a wide variety of diseases and an intense effort toward the development of specific PDEs inhibitors has been generated for the last years. They are the enzymes responsible for the hydrolysis of intracellular cyclic adenosine and guanosine monophosphate, and their complexity, as well as their different functional role, makes these enzymes a very attractive therapeutic target. This review is focused on the role of PDEs played on immunomodulatory processes and the advance on the development of specific inhibitors, covering PDEs mainly related to the regulation of autoimmune processes, PDE4 and PDE7. The review also highlights the novel structural classes of PDE4 and PDE7 inhibitors, and the therapeutic potential that combined PDE4/PDE7 inhibitors offer as immunomodulatory agents. © 2004 Wiley Periodicals, Inc. Med Res Rev [source] A cyclic adenosine 3,,5,-monophosphate-dependent protein kinase C activation is involved in the hyperactivation of boar spermatozoa,MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 9 2006Hiroshi Harayama Abstract An intracellular cAMP-PKA signaling plays a pivotal role in the expression of fertilizing ability in mammalian spermatozoa. The aim of this study is to disclose biological function of serine/threonine protein kinases that are activated by the action of the cAMP-PKA signaling in boar spermatozoa. Ejaculated spermatozoa were incubated with cBiMPS (a cell-permeable cAMP analog) at 38.5°C up to 180 min, and then they were used for biochemical analyses of PKCs by Western blotting and indirect immunofluorescence and for assessment of flagellar movement. The incubation of spermatozoa with cBiMPS gradually activated PKCs in the connecting piece. The activation of sperm PKCs was accompanied with changes of their electrophoretic mobility by the PKA-mediated serine/threonine phosphorylation. In coincidence with the PKC activation, the cBiMPS-incubated spermatozoa were capable of exhibiting hyperactivation of flagellar movement. Moreover, the cBiMPS-induced hyperactivation was dramatically suppressed by the addition of either of specific PKC inhibitors (Ro-32-0432 and bisindolylmaleimide I) to the sperm suspensions. On the other hand, experiments using a calcium-deficient medium showed that the cBiMPS-induced hyperactivation of flagellar movement and activation of PKCs required the extracellular calcium. Based on the obtained data, we have concluded that a cAMP-PKA signaling can induce activation of calcium-sensitive PKCs that is leading to the hyperactivation of flagellar movement in boar spermatozoa. Moreover, the cAMP may have a unique role as the up-regulator of PKCs during the expression of fertilizing ability in boar spermatozoa. Mol. Reprod. Dev. 1169,1178, 2006. © 2006 Wiley-Liss, Inc. [source] A unique mechanism for cyclic adenosine 3,,5,-monophosphate-induced increase of 32-kDa tyrosine-phosphorylated protein in boar spermatozoa,MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 2 2004Hiroshi Harayama Abstract A cAMP-induced increase of tyrosine-phosphorylated proteins is involved in the expression of fertilizing ability in mammalian spermatozoa. We (Harayama, 2003: J Androl 24:831,842) reported that incubation of boar spermatozoa with a cell-permeable cAMP analog (cBiMPS) increased a 32-kDa tyrosine-phosphorylated protein (TyrP32). The purpose of this study is to characterize the signaling cascades that regulate the cAMP-induced increase of TyrP32. We examined effects of tyrosine kinase inhibitor (lavendustin A), tyrosine phosphatase inhibitor (Na3VO4), cell-permeable calcium chelator (BAPTA-AM), and cholesterol acceptor (methyl-,-cyclodextrin: MBC) on the increase of TyrP32 and the change and loss of acrosomes in boar spermatozoa. The spermatozoa were used for detection of tyrosine-phosphorylated proteins by Western blotting and indirect immunofluorescence and for examination of acrosomal integrity by Giemsa staining. At least eight tyrosine-phosphorylated proteins including TyrP32 exhibited the cAMP-dependent increase during incubation with cBiMPS. In many proteins of them, this increase was reduced by lavendustin A but was enhanced by Na3VO4. In contrast, the cAMP-induced increase of TyrP32 was abolished by Na3VO4 but was hardly affected by lavendustin A. Giemsa staining showed that the increase of spermatozoa with weakly Giemsa-stained acrosomes (severely damaged acrosomes) or without acrosomes was correlative to the cAMP-induced increase of TyrP32. Moreover, the lack of calcium chloride in the incubation medium or pretreatment of spermatozoa with BAPTA-AM blocked the change and loss of acrosomes and the increase of TyrP32, suggesting these events are dependent on the extracellular and intracellular calcium. On the other hand, incubation of spermatozoa with MBC in the absence of cBiMPS could mimic the change and loss of acrosomes and increase of TyrP32 without increase of other tyrosine-phosphorylated proteins. Based on these results, we conclude that the cAMP-induced increase of TyrP32 is regulated by a unique mechanism that may be linked to the calcium-dependent change and loss of acrosomes. Mol. Reprod. Dev. 69: 194,204, 2004. © 2004 Wiley-Liss, Inc. [source] ,-Catenin expression in human neural cell lines following exposure to cytokines and growth factorsNEUROPATHOLOGY, Issue 2 2000Jun-ichi Satoh ,-Catenin acts as a key mediator of the Wnt/Wingless signaling pathway involved in cell proliferation, differentiation and survival. Recent studies have shown that an unstable interaction between ,-catenin and the mutant presenilin-1 induces neuronal apoptosis, and that ,-catenin levels are decreased in the brains of patients with Alzheimer's disease (AD). Since activated microglia and astrocytes play a role in the process of neuronal degeneration in AD, the cytokine/growth factor-regulated expression of ,-catenin in human neural cell lines, including NTera2 teratocarcinoma-derived differentiated neurons (NTera2-N), IMR-32 neuroblastoma, SKN-SH neuroblastoma and U-373MG astrocytoma, was studied quantitatively following exposure to epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), brain-derived neurotrophic factor (BDNF), tumor necrosis factor-, (TNF-,), interleukin (IL)-1,, IL-6, interferon (IFN)-,, transforming growth factor (TGF)-,1, dibutyryl cyclic adenosine 3,,5,-cyclic monophosphate (cAMP) (dbcAMP) or phorbol 12-myristate 13-acetate (PMA). ,-Catenin mRNA expressed constitutively in all of these cell lines was unaffected by treatment with any factors examined. In contrast, ,-catenin protein levels were reduced markedly in NTera2-N cells by exposure to dbcAMP, EGF or bFGF, and in U-373MG cells by treatment with dbcAMP or PMA, but were unaffected in any cell lines by BDNF, TNF-,, IL-1,, IL-6, IFN-, or TGF-,1. These results indicate that ,-catenin is expressed constitutively in human neural cells and downregulated at a protein level by a set of growth factors in a cell type-specific manner. [source] Integrated genomic and expression profiling in mantle cell lymphoma: identification of gene-dosage regulated candidate genesBRITISH JOURNAL OF HAEMATOLOGY, Issue 2 2008Margit Schraders Summary Mantle cell lymphoma (MCL) is characterized by the t(11;14)(q13;q32) translocation and several other cytogenetic aberrations, including heterozygous loss of chromosomal arms 1p, 6q, 11q and 13q and/or gains of 3q and 8q. The common intervals of chromosomal imbalance have been narrowed down using array-comparative genomic hybridization (CGH). However, the chromosomal intervals still contain many genes potentially involved in MCL pathogeny. Combined analysis of tiling-resolution array-CGH with gene expression profiling on 11 MCL tumours enabled the identification of genomic alterations and their corresponding gene expression profiles. Only subsets of genes located within given cytogenetic anomaly-intervals showed a concomitant change in mRNA expression level. The genes that showed consistent correlation between DNA copy number and RNA expression levels are likely to be important in MCL pathology. Besides several ,anonymous genes', we also identified various fully annotated genes, whose gene products are involved in cyclic adenosine monophosphate-regulated pathways (PRKACB), DNA damage repair, maintenance of chromosome stability and prevention of rereplication (ATM, ERCC5, FBXO5), energy metabolism (such as genes that are involved in the synthesis of proteins encoded by the mitochondrial genome) and signal transduction (ARHGAP29). Deregulation of these gene products may interfere with the signalling pathways that are involved in MCL tumour development and maintenance. [source] | |||||||||||||