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排序方式: 共有557条查询结果,搜索用时 9 毫秒
31.
Ilani T Fishburn CS Levavi-Sivan B Carmon S Raveh L Fuchs S 《Cellular and molecular neurobiology》2002,22(1):47-56
D2 and D3 dopamine receptors belong to the superfamily of G protein-coupled receptors; they share a high degree of homology and are structurally similar. However, they differ from each other in their second messenger coupling properties. Previously, we have studied the differential coupling of these receptors to G proteins and found that while D2 receptor couples only to inhibitory G proteins, D3 receptor couples also to a stimulatory G protein, Gs. We aimed to investigate the molecular basis of these differences and to determine which domains in the receptor control its coupling to G proteins. For this purpose four chimeras were constructed, each composed of different segments of the original D2 and D3 receptors. We have demonstrated that chimeras with a third cytoplasmic loop of D2 receptor couple to Gi protein in a pattern characteristic of D2 receptor. On the other hand chimeras containing a third cytoplasmic loop of D3 receptor have coupling characteristics like those of D3 receptor, and they couple also to Gs protein. These findings demonstrate that the third cytoplasmic loop determines and accounts for the coupling of dopamine receptors D2 and D3 to G proteins. 相似文献
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Zoltán Kellermayer Viktória Fisi Martina Mihalj Gergely Berta József Kóbor Péter Balogh 《The journal of histochemistry and cytochemistry》2014,62(6):436-449
The marginal zone (MZ) region of the spleen plays an important role in leukocyte traffic and the removal of blood-borne pathogens by resident macrophages. Macrophage receptor with a collagenous structure (MARCO), expressed by MZ macrophages, recognizes several microbial ligands and is also involved in the retention of MZ B cells. Here, we report that MARCO is also associated with follicular dendritic cells (FDCs) in the spleen. In its FDC-associated form MARCO is arranged in 0.3–0.5-μm diameter granular-fibrillar structures with an appearance similar to the white pulp conduit system formed by fibroblastic reticular cells (FRCs), but with different compartment preference. The follicular display of MARCO resists irradiation and requires the presence of both MZ macrophages and differentiated FDCs. The follicular delivery of MARCO is independent from the shuffling of marginal zone B cells, and it persists after clodronate liposome-mediated depletion of MZ macrophages. Our findings thus indicate that MARCO is distributed to both MZ and follicles within the spleen into conduit-like structures, where FDC-bound MARCO may mediate communication between the stromal microenvironments of MZ and follicles. 相似文献
34.
A. Fusconi A. M. Tagliasacchi G. Berta A. Trotta S. Brazzaventre F. Ruberti S. Scannerini 《Protoplasma》2000,214(3-4):219-226
Summary Arbuscular mycorrhizal (AM) fungi significantly improve plant growth in soils with low phosphorus availability and cause many changes in root morphology, similar to those produced by increased P nutrition, mainly depending on root apex size and activity. The aim of this work was to discriminate between the morphogenetic role of AM fungi and P in leek (Allium porrum L.) by feeding mycorrhizal and nonmycorrhizal plants with two nutrient solutions containing 3.2 or 96 M P and examining specific parameters related to adventitious root apices (apex size, mitotic cycle, and RNA synthesis). The results showed that AM fungi blocked meristem activity as indicated by the higher percentages of inactive apices and metaphases in the apical meristem of mycorrhizal plants, whereas the high P supply lengthened the mitotic cycle without blocking the apices, resulting in steady, slow root growth. The possible involvement of abscisic acid in the regulation of root apex activity is discussed.Abbreviations ABA
abscisic acid
- AM
arbuscular mycorrhizae
- CI and CII
nonmycorrhizal control plants grown with low or high phosphorus concentration
- MI and MII
mycorrhizal plants grown with low or high phosphorus concentration
- PGR
plant growth regulator 相似文献
35.
Gerard H. Bode Karin E. Pickl Maria Sanchez-Purrà Berta Albaiges Salvador Borrós Andy J. G. P?tgens Christoph Schmitz Frank M. Sinner Mario Losen Harry W. M. Steinbusch Hans-Georg Frank Pilar Martinez-Martinez European NanoBioPharmaceutics Research Initiative 《PloS one》2015,10(5)
AimsThe aim of the current study was to develop a method to detect peptide-linked nanoparticles in blood plasma.ResultsThe ELISA based method for the detection of FITC labeled peptides had a detection limit of 1 ng/mL. We were able to accurately measure peptides bound to pentafluorophenyl methacrylate nanoparticles in blood plasma of rats, and similar results were obtained by LC/MS.ConclusionsWe detected FITC-labeled peptides on pentafluorophenyl methacrylate nanoparticles after injection in vivo. This method can be extended to detect nanoparticles with different chemical compositions. 相似文献
36.
Esther C. Maier Ankur Saxena Berta Alsina Marianne E. Bronner Tanya T. Whitfield 《Developmental biology》2014
For both the intricate morphogenetic layout of the sensory cells in the ear and the elegantly radial arrangement of the sensory neurons in the nose, numerous signaling molecules and genetic determinants are required in concert to generate these specialized neuronal populations that help connect us to our environment. In this review, we outline many of the proteins and pathways that play essential roles in the differentiation of otic and olfactory neurons and their integration into their non-neuronal support structures. In both cases, well-known signaling pathways together with region-specific factors transform thickened ectodermal placodes into complex sense organs containing numerous, diverse neuronal subtypes. Olfactory and otic placodes, in combination with migratory neural crest stem cells, generate highly specialized subtypes of neuronal cells that sense sound, position and movement in space, odors and pheromones throughout our lives. 相似文献
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Ezequiel E. Larraburu Nancy M. Apóstolo Berta E. Llorente 《Trees - Structure and Function》2010,24(4):635-642
Photinia × fraseri Dress (photinia) is a woody plant with high ornamental value. The anatomy and morphology of micropropagated photinia inoculated
with the plant growth-promoting rhizobacteria Azospirillum brasilense and Azotobacter chroococcum, in combination with pulses of 49.2 μM indole-3-butyric acid during rhizogenesis, were characterized using light and electron
microscopy. Leaves of inoculated in vitro plants showed better development than those subjected to auxin control only. All
inoculated treatments, independent of the bacterial strain used, had leaves with two layers of palisade parenchyma, a thick
cuticle and linear unicellular trichomes. There was no proliferation of undifferentiated tissue in any treatment and the plants
showed shoot–root vascular connections. Ex vitro leaves and in vitro plants inoculated with Azospirillum brasilense Cd and Azotobacter chroococcum 42 had large stomata with elliptic aperture radially surrounded by small stomata on the abaxial foliar surface. In addition,
plants of these treatments had a large root hair zone over the root surface. Bacteria were only observed on surfaces of root
hairs. The results suggest that the structural changes induced by bacterial inoculation of photinia in vitro plants could
lead to better adaptation to ex vitro conditions after transplanting. 相似文献
39.
Suelves M Vidal B Serrano AL Tjwa M Roma J López-Alemany R Luttun A de Lagrán MM Díaz-Ramos A Díaz MA Jardí M Roig M Dierssen M Dewerchin M Carmeliet P Muñoz-Cánoves P 《The Journal of cell biology》2007,178(6):1039-1051
Duchenne muscular dystrophy (DMD) is a fatal and incurable muscle degenerative disorder. We identify a function of the protease urokinase plasminogen activator (uPA) in mdx mice, a mouse model of DMD. The expression of uPA is induced in mdx dystrophic muscle, and the genetic loss of uPA in mdx mice exacerbated muscle dystrophy and reduced muscular function. Bone marrow (BM) transplantation experiments revealed a critical function for BM-derived uPA in mdx muscle repair via three mechanisms: (1) by promoting the infiltration of BM-derived inflammatory cells; (2) by preventing the excessive deposition of fibrin; and (3) by promoting myoblast migration. Interestingly, genetic loss of the uPA receptor in mdx mice did not exacerbate muscular dystrophy in mdx mice, suggesting that uPA exerts its effects independently of its receptor. These findings underscore the importance of uPA in muscular dystrophy. 相似文献
40.