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81.
James R. Bunzow Ge Zhang Claudia Bouvier Carmen Saez Oline K. Ronnekleiv Martin J. Kelly David K. Grandy 《Journal of neurochemistry》1995,64(1):14-24
Abstract: We have cloned and expressed a rat brain cDNA, TS11, that encodes a μ-opioid receptor based on pharmacological, physiological, and anatomical criteria. Membranes were prepared from COS-7 cells transiently expressing TS11 bound [3H]diprenorphine with high affinity (KD = 0.23 ± 0.04 nM). The rank order potency of drugs competing with [3H]diprenorphine was as follows: levorphanol (Ki = 0.6 ± 0.2 nM) ≈β-endorphin (Ki = 0.7 ± 0.5 nM) ≈ morphine (Ki = 0.8 ± 0.5 nM) ≈ [d -Ala2, N-Me-Phe4,Gly-ol5]-enkephalin (DAMGO; Ki = 1.6 ± 0.5 nM) ? U50,488 (Ki = 910 ± 0.78 nM) > [d -Pen2,5]-enkephalin (Ki = 3,170 ± 98 nM) > dextrorphan (Ki = 4,100 ± 68 nM). The rank order potencies of these ligands, the stereospecificity of levorphanol, and morphine's subnanomolar Ki are consistent with a μ-opioid binding site. Two additional experiments provided evidence that this opioid-binding site is functionally coupled to G proteins: (a) In COS-7 cells 50 µM 5′-guanylylimidodiphosphate shifted a fraction of receptors with high affinity for DAMGO (IC50 = 3.4 ± 0.5 nM) to a lower-affinity state (IC50 = 89.0 ± 19.0 nM), and (b) exposure of Chinese hamster ovary cells stably expressing the cloned μ-opioid receptor to DAMGO resulted in a dose-dependent, naloxone-sensitive inhibition of forskolin-stimulated cyclic AMP production. The distribution of mRNA corresponding to the μ-opioid receptor encoded by TS11 was determined by in situ hybridization to brain sections prepared from adult female rats. The highest levels of μ-receptor mRNA were detected in the thalamus, medial habenula, and the caudate putamen; however, significant hybridization was also observed in many other brain regions, including the hypothalamus. 相似文献
82.
Claudia M. Caillaud J. S. Pierre B. Chaubet J. P. Di Pietro 《Entomologia Experimentalis et Applicata》1995,75(1):9-18
The behaviour ofSitobion avenae (F.), was compared on resistant wheat lines ofTriticum monococcum (L.) and a susceptible variety ofTriticum aestivum (L.). Firstly, stylet penetration activities were monitored with the Electrical Penetration Graph (EPG) technique and subsequently
analysed using flow charts combined with correspondence analysis. Plant resistance was shown to be associated with repeated
penetrations without access to either the xylem or the phloem, and with numerous failures in starting a sustained sap ingestion
(as represented by pattern E2). Access to sieve elements of the phloem did not seem to be much affected on resistant plants
but it took the aphid three times as long to produce a sap ingestion pattern when maintained on the resistant lineT. monococcum no 44 (Tm44) as compared with aphids maintained on susceptible plants. As a result the total time spent in ingesting from sieve
elements was reduced by 72% on Tm44. Secondly, direct observations of freely-moving apterous adults were performed. Aphids
did not discriminate between resistant and susceptible wheat during the first 30 min of access to test leaves, but only 4
out of 25 aphids were still probing after eight hours on resistant Tm44.
The relevance of these results to possible location of the resistance factor(s) are discussed. Although detection of plant
resistance before sieve elements are reached can not be rigorously excluded, the factors involved inT. monococcum resistance toS. avenae undoubtedly occur within the phloem vessels. 相似文献
83.
Contactinhibin was found to be involved in contact-dependent inhibition of growth. The growth inhibitory activity of contactinhibin is mediated by N-linked oligosaccharides with desialylated -glycosidically linked, terminal galactose residues. Here we show that in sparse human fibroblasts contactinhibin was expressed in a biologically inactive, highly sialylated form both on the plasma membrane and intracellularily, while in confluent cells plasma membrane localized contactinhibin was present in a biologically active, low sialylated form. Plasma membranes were shown to contain a glycoprotein sialidase which is suggested to be engaged in the activation of contactinhibin in a cell contact-dependent manner. 相似文献
84.
Xavier Isaac M. de Pádua Antônio Moraes Fernando De Miranda-Neto J. A. 《Molecular Engineering》1997,7(3-4):283-291
Starburst dendrimers are highly branched oligomers. A rigid dendritic hydrocarbon, C1134H1146, has recently been synthesized. It consists of 94 phenylacetylene units displayed in a self-similar two-dimensional skeleton
isomorphous to the three-coordinated Bethe lattice. The three-dimensional representation of phenylacetylene dendrimer shows
a globular architecture with large voids and niches in its interior, characteristic of hyperbolic surfaces. This work investigates
the geometrical scaling behavior of this starburst dendrimer using the symmetry properties of a Bethe lattice embedded in
the hyperbolic plane. The results for C1134H1146 provide its density profile and an upper bound for its macromolecular size.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
85.
Isolation and characterization of the mycobacterial phagosome: segregation from the endosomal/lysosomal pathway 总被引:5,自引:0,他引:5
Zahra Hasan Claudia Schlax Lotte Kuhn Ivan Lefkovits Douglas Young Jelle Thole & Jean Pieters 《Molecular microbiology》1997,24(3):545-553
Mycobacteria have the ability to persist within host phagocytes, and their success as intracellular pathogens is thought to be related to the ability to modify their intracellular environment. After entry into phagocytes, mycobacteria-containing phagosomes acquire markers for the endosomal pathway, but do not fuse with lysosomes. The molecular machinery that is involved in the entry and survival of mycobacteria in host cells is poorly characterized. Here we describe the use of organelle electrophoresis to study the uptake of Mycobacterium bovis bacille Calmette Guerin (BCG) into murine macrophages. We demonstrate that live, but not dead, mycobacteria occupy a phagosome that can be physically separated from endosomal/lysosomal compartments. Biochemical analysis of purified mycobacterial phagosomes revealed the absence of endosomal/lysosomal markers LAMP-1 and β-hexosaminidase. Combining subcellular fractionation with two-dimensional gel electrophoresis, we found that a set of host proteins was present in phagosomes that were absent from endosomal/lysosomal compartments. The residence of mycobacteria in compartments outside the endosomal/lysosomal system may explain their persistence inside host cells and their sequestration from immune recognition. Furthermore, the approach described here may contribute to an improved understanding of the molecular mechanisms that determine the intracellular fate of mycobacteria during infection. 相似文献
86.
87.
88.
Maurizio Meta Marco Ponte Marina Guastella Claudia Semino Gabriella Pietra Giovanni Battista Ratto Giovanni Melioli 《Cancer immunology, immunotherapy : CII》1995,40(4):235-240
Despite the combined use of surgery and chemoradiotherapy, the poor prognosis of advanced non-smallcell lung cancer (NSCLC) requires the definition of new therapeutic approaches. The presence of T lymphocytes, with peculiar phenotypic, functional and molecular characteristics within the tumour, suggested the possible use of these cells, expanded in vitro, in protocols of adoptive immunotherapy. We have described how a population of oligoclonal T lymphocytes, derived from advanced NSCLC, can be expanded in vitro and has the capability of lysing autologous cancer cells. What is more important, we observed that patients with advanced NSCLC, treated with TIL expanded in vitro and recombinant interleukin-2, seemed to have a disease-free period longer than that of patients treated with conventional chemoradiotherapy. in an attempt to find new sources of specific lymphocytes for immunotherapy, we describe the analysis of the phenotypic, functional and molecular characteristics of T lymphocytes, derived from lymph nodes draining advanced NSCLC. In this paper we show that these cells, have restriction patterns of T cell receptor chain similar to those detectable in the population of infiltrating T lymphocytes. This finding suggests that T cells derived from draining lymph nodes of advanced NSCLC have peculiar characteristics and can be a suitable source of effector cells for protocols of adoptive immunotherapy in lung cancer treatment. 相似文献
89.
Pili of Pasteurella multocida of porcine origin 总被引:1,自引:0,他引:1
Abstract Using electron microscopy, pili with at least two distinct morphologies were observed on strains of Pasteurella multocida isolated from pigs with atrophic rhinitis. Rigid pili were found on 60–80% of all cells observed. These pili had a strong tendency to lie flat along the side of the outer cell membrane of P. multocida and as a result frequently were difficult to see. After growth in vitro, piliated P. multocida cells produced few pili (approx. 3–5 per cell). Heavily piliated cells were occasionally observed. The second type of pili were curly and also were difficult to visualize. Cells from cultures containing piliated cells failed to attach to red blood cells and to immobilized mucus. 相似文献
90.
Marden A. de Alvarenga Raimundo Braz Fo Otto R. Gottlieb João P. de P. Dias Aderbal F. Magalhães Eva G. Magalhães Gouvan C. de Magalhães Mauro T. Magalhães José G.S. Maia Raquel Marques Anita J. Marsaioli Antônio A.L. Mesquita Anselmo A. de Moraes Alaide B. de Oliveira Geovane G. de Oliveira Gentil Pedreira Sebastião K. Pereira Sonildes L.V. Pinho Celira C. Santos 《Phytochemistry》1978,17(3):511-516
Wood samples, infested by fungi during storage, were shown to contain, besides the known 5-methyl-mellein, additional (3R)-8-hydroxy-3-methyl-3,4-dihydroisocoumarins substituted by 7-methyl, 5-formyl, 5-carboxy, 5-hydroxy, 5-methoxy, 6-methoxy-5-methyl and 6,7-dimethoxy-5-methyl groups, as well as 6-formyl-7-hydroxy-5-methoxy-4-methylphthalide. Several 2-methylchromanones were synthesized in order to show that this class of compounds can be distinguished from 3-methyl-3,4-dihydroisocoumarins by MS. 相似文献