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991.
Stefanachi A Nicolotti O Leonetti F Cellamare S Campagna F Loza MI Brea JM Mazza F Gavuzzo E Carotti A 《Bioorganic & medicinal chemistry》2008,16(22):9780-9789
A number of 1,3-dialkyl-8-(hetero)aryl-9-OH-9-deazaxanthines were prepared and evaluated as ligands of recombinant human adenosine receptors (hARs). Several 1,3-dipropyl derivatives endowed with nanomolar binding affinity at hA(2B) receptors, but poor selectivity over hA(2A), hA(1) and hA(3) AR subtypes were identified. A comparison with the corresponding 7-OH- and 7,9-unsubstituted-deazaxanthines revealed that 9-OH-9-deazaxanthines are more potent hA(2B) ligands with lower partition coefficients and higher water solubility compared to the other two congeneric classes of deazaxanthines. An optimization of the para-substituent of the 8-phenyl ring of 9-OH-9-deazaxanthines led to the discovery of compound 38, which exhibited outstanding hA(2B) affinity (Ki=1.0 nM), good selectivity over hA(2A), hA(1) and hA(3) (selectivity indices=100, 79 and 1290, respectively) and excellent antagonist potency in a functional assay on rat A(2B) (pA(2B)=9.33). 相似文献
992.
993.
Evapotranspiration and crop coefficient of poplar and willow short-rotation coppice used as vegetation filter 总被引:1,自引:0,他引:1
Ten-day evapotranspiration (ETc) and crop coefficient (k(c)) of willow and poplar SRC used as vegetation filter and grown under fertilised (F) and unfertilised (NF) conditions, were determined for two successive growing seasons using volumetric lysimeters. During the first growing season, total ETc observed was, respectively, 620 (NF)-1190 (F)mm in willow and 590 (NF)-725 (F) in poplar. During the second growing season, ETc showed a general increase, mainly in fertilised lysimeters where it ranged between 890 (NF)-1790 mm (F) in willow and 710 (NF)-1100 mm (NF) in poplar. kc reached in both years its maximum between the end of August and the beginning of September. In 2004 maximum kc ranged from 1.25-2.84 in willow and 1.06-1.90 in poplar, whereas in 2005 it ranged from 1.97-5.30 in willow and 1.71-4.28 in poplar. ETc seemed to be strongly correlated to plant development and mainly dependent on its nutritional status rather than on the differences between the species. 相似文献
994.
Maria Grazia Di Certo Enrico M Batassa Ida Casella Annalucia Serafino Aristide Floridi Claudio Passananti Paola Molinari Elisabetta Mattei 《BMC cell biology》2008,9(1):56
Background
Chimeric proteins obtained by the fusion of a G protein-coupled receptor (GPCR) sequence to the N-terminus of the G protein α-subunit have been extensively used to investigate several aspects of GPCR signalling. Although both the receptor and the G protein generally maintain a fully functional state in such polypeptides, original observations made using a chimera between the β2-adrenergic receptor (β2AR) and Gαs indicated that the fusion to the α-subunit resulted in a marked reduction of receptor desensitization and down-regulation. To further investigate this phenomenon, we have compared the rates of internalization and recycling between wild-type and Gαs-fused β2AR. 相似文献995.
996.
Enrico Braidot Marco Zancani Elisa Petrussa Carlo Peresson Alberto Bertolini Sonia Patui Francesco Macrì Angelo Vianello 《Plant signaling & behavior》2008,3(9):626-632
Flavonoids are a group of secondary metabolites widely distributed in plants that represent a huge portion of the soluble phenolics present in grapevine (Vitis vinifera L.). These compounds play different physiological roles and are often involved in protection against biotic and abiotic stress. Even if the flavonoid biosynthetic pathways have been largely characterized, the mechanisms of their transport and accumulation in cell wall and vacuole are still not completely understood. This review analyses the known mechanisms of flavonoid uptake and accumulation in grapevine, with reference to the transport models and membrane carrier proteins described in other plant species. The effect of different environmental factors on flavonoid biosynthesis and transporters is also discussed.Key words: ABC proteins, active transport, bilitranslocase, biotic and abiotic stress, flavonoid, secondary metabolites 相似文献
997.
Montagnoli A Valsasina B Croci V Menichincheri M Rainoldi S Marchesi V Tibolla M Tenca P Brotherton D Albanese C Patton V Alzani R Ciavolella A Sola F Molinari A Volpi D Avanzi N Fiorentini F Cattoni M Healy S Ballinari D Pesenti E Isacchi A Moll J Bensimon A Vanotti E Santocanale C 《Nature chemical biology》2008,4(6):357-365
Cdc7 is an essential kinase that promotes DNA replication by activating origins of replication. Here, we characterized the potent Cdc7 inhibitor PHA-767491 (1) in biochemical and cell-based assays, and we tested its antitumor activity in rodents. We found that the compound blocks DNA synthesis and affects the phosphorylation of the replicative DNA helicase at Cdc7-dependent phosphorylation sites. Unlike current DNA synthesis inhibitors, PHA-767491 prevents the activation of replication origins but does not impede replication fork progression, and it does not trigger a sustained DNA damage response. Treatment with PHA-767491 results in apoptotic cell death in multiple cancer cell types and tumor growth inhibition in preclinical cancer models. To our knowledge, PHA-767491 is the first molecule that directly affects the mechanisms controlling initiation as opposed to elongation in DNA replication, and its activities suggest that Cdc7 kinase inhibition could be a new strategy for the development of anticancer therapeutics. 相似文献
998.
Fogli M Mavilio D Brunetta E Varchetta S Ata K Roby G Kovacs C Follmann D Pende D Ward J Barker E Marcenaro E Moretta A Fauci AS 《PLoS pathogens》2008,4(7):e1000101
Understanding the cellular mechanisms that ensure an appropriate innate immune response against viral pathogens is an important challenge of biomedical research. In vitro studies have shown that natural killer (NK) cells purified from healthy donors can kill heterologous cell lines or autologous CD4+ T cell blasts exogenously infected with several strains of HIV-1. However, it is not known whether the deleterious effects of high HIV-1 viremia interferes with the NK cell-mediated cytolysis of autologous, endogenously HIV-1-infected CD4+ T cells. Here, we stimulate primary CD4+ T cells, purified ex vivo from HIV-1-infected viremic patients, with PHA and rIL2 (with or without rIL-7). This experimental procedure allows for the significant expansion and isolation of endogenously infected CD4+ T cell blasts detected by intracellular staining of p24 HIV-1 core antigen. We show that, subsequent to the selective down-modulation of MHC class-I (MHC-I) molecules, HIV-1-infected p24(pos) blasts become partially susceptible to lysis by rIL-2-activated NK cells, while uninfected p24(neg) blasts are spared from killing. This NK cell-mediated killing occurs mainly through the NKG2D activation pathway. However, the degree of NK cell cytolytic activity against autologous, endogenously HIV-1-infected CD4+ T cell blasts that down-modulate HLA-A and -B alleles and against heterologous MHC-I(neg) cell lines is particularly low. This phenomenon is associated with the defective surface expression and engagement of natural cytotoxicity receptors (NCRs) and with the high frequency of the anergic CD56(neg)/CD16(pos) subsets of highly dysfunctional NK cells from HIV-1-infected viremic patients. Collectively, our data demonstrate that the chronic viral replication of HIV-1 in infected individuals results in several phenotypic and functional aberrancies that interfere with the NK cell-mediated killing of autologous p24(pos) blasts derived from primary T cells. 相似文献
999.
Chloroplast movement as a response of plants to light variations is presented as an example in each classical textbook, showing that these organelles accumulate in response to low light and avoid high light irradiation. In sharp contrast to the morphological discovery of the phenomenon, which dates back more than a century, the molecular understanding of this effect is just at its beginning and only recently first components of the signal cascade initiating this process were described. Among these, a protein termed CHUP1 was identified. This protein is present in the outer membrane of chloroplasts and thereby discussed as the first component of a possible ‘moving ensemble’ assembling at the ‘moved cargo’. The protein is able to interact with actin and profilin—and even more, is able to regulate this interaction in vitro. Thereby, today it can be stated that actin filament reformation and chloroplast repositioning are coordinated if not dependent on each other.Key words: chloroplast movement, profilin binding, actin binding, avoidance response of chloroplasts 相似文献
1000.
Luca Pasini Maria Rosaria Stile Enrico Puja Rita Valsecchi Priscilla Francia Giorgia Carletti Francesco Salamini Adriano Marocco 《Molecular breeding : new strategies in plant improvement》2008,22(4):527-541
In this paper, 10 mutations conditioning the appearance of defective, miniature or collapsed endosperm, but with normal sporophyte
development, were considered. Homozygous mutant kernels have reduced grain weight, kernel size, density and, in some of these,
higher than normal seed protein content. The mutant loci were integrated into a high-resolution genetic map in order to associate
them to specific genes. We have placed 1167 AFLP markers on a consensus map using IBM2 as a backbone and reaching an average
of 1 marker every 1.9 cM. We have identified AFLP markers linked to all individual mutant alleles. BSA was adopted to screen
the largest possible number of primer combinations on homozygous F3 mutant and wild type plants. The ten mutant loci are linked to the closest AFLP or SSR markers with distances ranging from
0 to 17.9 cM. The genes we have defined by the existence of mendelian mutants can now be considered good candidates for testing
the association to QT loci.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献