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941.
942.
Neuroglobin, a novel member of the globin family, is expressed in focal regions of the brain. 总被引:13,自引:0,他引:13
Pradeep P A Mammen John M Shelton Sean C Goetsch S Clay Williams James A Richardson Mary G Garry Daniel J Garry 《The journal of histochemistry and cytochemistry》2002,50(12):1591-1598
Hemoproteins are widely distributed among unicellular eukaryotes, plants, and animals. In addition to myoglobin and hemoglobin, a third hemoprotein, neuroglobin, has recently been isolated from vertebrate brain. Although the functional role of this novel member of the globin family remains unclear, neuroglobin contains a heme-binding domain and may participate in diverse processes such as oxygen transport, oxygen storage, nitric oxide detoxification, or modulation of terminal oxidase activity. In this study we utilized in situ hybridization (ISH) and RT-PCR analyses to examine the expression of neuroglobin in the normoxic and hypoxic murine brain. In the normoxic adult mouse, neuroglobin expression was observed in focal regions of the brain, including the lateral tegmental nuclei, the preoptic nucleus, amygdala, locus coeruleus, and nucleus of the solitary tract. Using ISH and RT-PCR techniques, no significant changes in neuroglobin expression in the adult murine brain was observed in response to chronic 10% oxygen. These results support the hypothesis that neuroglobin is a hemoprotein that is expressed in the brain and may have diverse functional roles. 相似文献
943.
Impact of engagement of FcepsilonRI and CC chemokine receptor 1 on mast cell activation and motility
Toda M Dawson M Nakamura T Munro PM Richardson RM Bailly M Ono SJ 《The Journal of biological chemistry》2004,279(46):48443-48448
CC chemokines participate in the recruitment and activation of immune cells through CC chemokine receptors (CCRs). Here, we report that cross-talk between CCR1-mediated signaling pathway and FcepsilonRI-mediated signaling pathway affects degranulation positively but affects chemotaxis of mast cells adversely. Costimulation via FcepsilonRI engagement with IgE/antigen and CCR1 engagement with recombinant human CCL3 synergistically enhanced degranulation in rat basophilic leukemia-2H3 cells expressing human CCR1 (RBL-CCR1). Interestingly, FcepsilonRI engagement inhibited CCL3-mediated chemotaxis and membrane ruffling of RBL-CCR1 cells. Small GTP-binding proteins of the Rho family, Rac, Cdc42, and Rho control chemotaxis by mediating the reorganization of the actin cytoskeleton. Both a Rho inhibitor C3 exoenzyme and a Rho kinase (ROCK) inhibitor Y-27632 inhibited chemotaxis of RBL-CCR1 cells toward CCL3, indicating that activation of the Rho/ROCK signaling pathway is required for the CCL3-mediated chemotaxis of the cells. Costimulation with IgE/antigen and CCL3 enhanced Rac and Cdc42 activation but decreased ROCK activation in RBL-CCR1 cells compared with that in the cells stimulated with CCL3 alone. These results suggest that costimulation via FcepsilonRI and CCR1 engagements induced 1) inhibition of membrane ruffling, 2) decreased ROCK activation, and 3) reciprocal imbalance between Small GTP-binding proteins of the Rho family, which result in the inhibition of chemotaxis of RBL-CCR1 cells. The cross-talk between FcepsilonRI-mediated signaling pathway and CCR-mediated signaling pathway would induce optimal activation and arrested chemotaxis of mast cells, thus contributing to allergic inflammation. 相似文献
944.
Electron microscopic and crystallographic data have shown that the gene 4 primase/helicase encoded by bacteriophage T7 can form both hexamers and heptamers. After cross-linking with glutaraldehyde to stabilize the oligomeric protein, hexamers and heptamers can be distinguished either by negative stain electron microscopy or electrophoretic analysis using polyacrylamide gels. We find that hexamers predominate in the presence of either dTTP or beta,gamma-methylene dTTP whereas the ratio between hexamers and heptamers is nearly the converse in the presence of dTDP. When formed, heptamers are unable to efficiently bind either single-stranded DNA or double-stranded DNA. We postulate that a switch between heptamer to hexamer may provide a ring-opening mechanism for the single-stranded DNA binding pathway. Accordingly, we observe that in the presence of both nucleoside di- and triphosphates the gene 4 protein exists as a hexamer when bound to single-stranded DNA and as a mixture of heptamer and hexamer when not bound to single-stranded DNA. Furthermore, altering regions of the gene 4 protein postulated to be conformational switches for dTTP-dependent helicase activity leads to modulation of the heptamer to hexamer ratio. 相似文献
945.
Thandeka Moyo-Gwete Mashudu Madzivhandila Nonhlanhla N. Mkhize Prudence Kgagudi Frances Ayres Bronwen E. Lambson Nelia P. Manamela Simone I. Richardson Zanele Makhado Mieke A. van der Mescht Zelda de Beer Talita Roma de Villiers Wendy A. Burgers Ntobeko A. B. Ntusi Theresa Rossouw Veronica Ueckermann Michael T. Boswell Penny L. Moore 《Journal of virology》2022,96(15)
946.
Cato S.A. Corbett G.E. Richardson T.E. 《Molecular breeding : new strategies in plant improvement》1999,5(3):275-281
Efficient construction of reasonable density genetic linkage maps is an essential component of QTL detection programmes. The
AFLP technique has been used to produce genetic linkage maps in a range of species. We have developed protocols to generate
reproducible AFLP profiles in Pinus radiata and have evaluated the inheritance and informativeness of AFLP markers in this
important timber species. The large genome size of P. radiata necessitated increased levels of selection at both the pre-amplification
and selective amplification steps of the AFLP protocol to generate reproducible AFLP profiles. Once optimised ca. 41.3 scorable
AFLP bands were resolvable through denaturing gels, of which 48.4% were polymorphic in a screen of eight unrelated trees.
This level of polymorphism is ca. three times higher than with RAPD markers. The total number of bands and the number of polymorphismic
bands per PCR were ca. halved when AFLPs were electrophoresed on non-denaturing gels and stained with ethidium bromide. Using
the protocols developed, AFLP is an efficient method for generating the DNA markers required for genetic linkage map construction
in P. radiata.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
947.
This study examines the level of isolation of arthropod faunas present on specimens of the endemic woodland tree Melaleuca linariifolia by investigating the recovery of faunas after defaunation using insecticide. One tree from each of 21 pairs of trees was sprayed at the beginning of the project (early April 1994). After predetermined periods, three test trees were resprayed along with matched control trees. A total of 95 154 arthropods were collected and sorted during the project. The number of species present on the trees recovered within 16 weeks of spraying, with common species recolonizing within a fortnight. The rarer species both of mobile (Diptera) and relatively sedentary (Araneae) taxa reappeared at similar rates. Complete recovery of numbers occurred by week 8 after spraying. Evenness (as Simpson’s D) recovered over the first 2 months; however, both the number of individuals and the evenness continued to diverge from the pattern seen on the control trees until the end of the study. While the rate of movement of individuals and species was such as to provide an apparently complete set of replacement species within several months of perturbation, the structure of the community found on the trees was still seriously disrupted after 1 year. Comparison of the suites of species originally found on the trees with those found in the respray samples and the control samples showed that the set of colonizing species was no more similar to the original fauna of the tree than it was to those on the control tree. The relatively rapid colonization of the trees by a suite of rare species – not necessarily those that were on particular trees before perturbation – indicates that rarity was due neither to inability of the species to colonize the trees nor to the suitability of the trees for these species. Recovery of rare species was to a level similar to that found on the control trees. That the divergences from the controls continued (in number of individuals and in evenness), implies a definite connection between the different faunas of a tree and their partial isolation from fauna communities on other trees. Whatever the forces that maintain suites of species on each tree, it is not the ability of the species to reach and colonize trees, nor certain attributes of a tree, that make it suitable only for a particular subset of the species available. Trees are not isolated entities but neither are they part of a fully integrated community, either chronologically or spacially, and issues of scale are also likely to be important in understanding and estimating the dynamics and factors regulating biodiversity levels. 相似文献
948.
GIGANTEA: a circadian clock-controlled gene that regulates photoperiodic flowering in Arabidopsis and encodes a protein with several possible membrane-spanning domains. 总被引:19,自引:0,他引:19 下载免费PDF全文
S Fowler K Lee H Onouchi A Samach K Richardson B Morris G Coupland J Putterill 《The EMBO journal》1999,18(17):4679-4688
949.
950.
Abstract: The ability of adenosine agonists to modulate K+ -evoked 4D†-[3 H]aminobutyric acid ([3 H]GABA) and acetylcholine (ACh) release from rat striatal synaptosomes was investigated. The A2a receptor-selective agonist CGS 21680 inhibited Ca2+ -dependent [3 H]GABA release evoked by 15 m M KCI with a maximal inhibition of 29 ± 4% (IC50 of ∼4 ± 10 −12 M ). The relative order of potency of three agonists was CGS 21680 ± 5'- N -ethylcarboxamidoadenosine > R-phenylisopropyladenosine (R-PIA), with the inhibition being blocked by A2a receptor-selective antagonists (CP 66,713 and CGS 15943A) but not by the A1 -selective antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). When release of [3 H]GABA was evoked by 30 mM KCI, no significant inhibition was observed. In contrast, CGS 21680 stimulated the release of [3 H]ACh evoked by 30 m M KCI, with a maximal stimulation of 26 ± 5% (IC50 of ∼10−11 M ). This effect was blocked by CP 66,713 but not by DPCPX. The A1 agonist R -PIA inhibited [3 H]ACh release, an effect blocked by DPCPX. It is concluded that adenosine A2a receptors are present on both GABAergic and cholinergic striatal nerve terminals where they inhibit and stimulate transmitter release, respectively. Key Words : GABA—Acetylcholine—Adenosine receptors—Striatum. 相似文献