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排序方式: 共有213条查询结果,搜索用时 15 毫秒
1.
Using an antibody generated against the opiate receptor on NG108-15 cells, we recently purified the putative receptor from this hybrid cell line. We herein report that the purified receptor complex specifically binds tritiated cis-(+)-3-methylfentanylisothiocyanate (SUPERFIT), with the predominant binding associated with a 58 kDa polypeptide chain. Consistent with these findings is the in situ labeling of a 58 kDa protein with [3H]SUPERFIT on NG108-15 cells. 相似文献
2.
Structural relatedness of lysis proteins from colicinogenic plasmids and icosahedral coliphages 总被引:4,自引:0,他引:4
The host-lysis-inducing functions of phi X174 protein E and MS2 protein L
were recently shown to reside on the N-terminal and C-terminal halves of
the two respective lysis proteins. In the present study it is shown that
the small lysis proteins encoded in various colicinogenic plasmids share
local sequence similarities and certain structural characteristics with the
essential peptides of their coliphage-coded counterparts. Despite their
dissimilar sizes and origins, it is suggested that the colicinogenic lysis
proteins are functionally analogous and evolutionarily related to those of
icosahedral single- stranded DNA and RNA phages.
相似文献
3.
Cecilia PC Soh Alastair SR Donald James Feeney Walter TJ Morgan Winifred M Watkins 《Glycoconjugate journal》1989,6(3):319-332
The tetrasaccharides GalNAcß1-4[NeuAc2-3]Galß1-4Glc and GalNAcß1-4[NeuAc2-3]Galß1-4GlcNAc were synthesised by enzymic transfer of GalNAc from UDP-GalNAc to 3-sialyllactose (NeuAc2-3Galß1-4Glc) and 3-sialyl-N-acetyllactosamine (NeuAc2-3Galß1-4GlcNAc). The structures of the products were established by methylation and1H-500 MHz NMR spectroscopy. In Sda serological tests the product formed with 3-sialyl-N-acetyllactosamine was highly active whereas that formed with 3-sialyllactose had only weak activity. 相似文献
4.
In the present study, we evaluated whether mononuclear leukocytes could synthesize and secrete growth hormone (GH) in vitro. By using RNA slot blot analysis, we detected maximum spontaneous levels of specific GH mRNA in the cytoplasm of rat leukocytes after a 4-h incubation. Northern gel analysis demonstrated that the specific leukocyte GH RNA was polyadenylated and had a molecular mass of 1.0 kb. Further studies using immunofluorescence, antibody affinity chromatography, and Sephacryl gel filtration indicate that leukocytes secrete a high molecular weight (greater than 300,000) and a low molecular weight (approximately 22,000) immunoreactive GH (irGH). A substantial amount of the high molecular weight irGH can be converted to the lower molecular weight form after reduction with mercaptoethanol. The irGH appeared to be de novo synthesized because it could be radiolabeled with tritiated amino acids and its production could be blocked by previous incubation of leukocytes with cycloheximide. The replication of Nb2 rat node lymphoma cells was stimulated by affinity-purified human lymphocyte-derived irGH. The growth stimulation was blocked by specific antibodies to hGH. We conclude that lymphocytes produce an irGH that is similar to if not identical to pituitary GH in terms of bioactivity, antigenicity, and molecular weight. The findings demonstrate a potential regulatory loop between the immune and neuroendocrine tissues. 相似文献
5.
The absence (or decrease) of the hydrostatic pressure during space flights (microgravity state) or simulations of weightlessness (by immersion, bed rest or head-down tilt) result in a body fluid shift and an engorgement of the central circulation where mechanoreceptors involved in plasma volume regulation are located. Their activation induces the initial (first hours) hormonal response with a decrease in plasma vasopressin, renin and aldosterone and probably an increase in a natriuretic factor (Gauer reflex). Prolonged exposure to microgravity leads to more complex and often hypothetical responses: cardiovascular deconditioning, modifications in secretion and circadian rhythms of above cited hormones. After 24 years of studies on approximately 200 astronauts our knowledge of cardiovascular and hormonal adaptation to space flight is still at the beginning. 相似文献
6.
7.
D W Pascual J E Blalock K L Bost 《Journal of immunology (Baltimore, Md. : 1950)》1989,143(11):3697-3702
In an effort to investigate the presence of substance P (SP) receptors on lymphocytes, polyclonal antibodies against SP receptors were developed. The immunogen used to generate these antibodies was a peptide encoded by an RNA complementary to the mRNA for SP. The rationale for using this SP complementary peptide (termed SP CP) as an immunogen resulted from the observation that 3H-SP bound to microtiter wells coated with SP CP in a dose dependent and saturable fashion. Furthermore, binding was blocked with excess unlabeled SP or SP antagonist, D-Pro2-D-Phe7-D-Trp9-SP. Inasmuch as the peptide, SP CP, specifically bound 3H-SP, we hypothesized that antibodies against this peptide might recognize a SP receptor binding site. Using the SP receptor positive lymphoblast cell line, IM-9, affinity-purified antibodies against SP CP but not antibodies against keyhole limpet hemocyanin recognized a molecule on the surface of IM-9 cells. Anti-SP CP binding to IM-9 cells was blocked with excess SP antagonist, suggesting that the antibody and the SP antagonist were competing for the same binding site. In support of this possibility, anti-SP CP antibodies blocked 3H-SP binding to IM-9 cells. An immunoaffinity column coupled with antibodies against SP CP bound protein from solubilized IM-9 cells. This isolated protein bound 125I-Tyr8-SP and binding was specifically blocked with SP as well as by SP antagonist, neurokinin A, and eledoisin. Passthrough material did not bind SP suggesting that a SP receptor had been purified. Western blot analysis of solubilized IM-9 cell proteins using anti-SP CP antibodies but not preimmune IgG recognized a single protein of 58,000 D. Taken together, these results demonstrate that antibodies against SP CP recognize a SP receptor present on the lymphocyte cell line, IM-9. 相似文献
8.
B. M. Culik K. Pütz R. P. Wilson C. A. Bost Y. Le Maho J. -L. Verselin 《Polar Biology》1996,16(5):371-378
Core temperature was determined in two king penguins living in the wild at Ile de la Possession, Crozel Archipelago, using
implantable four-channel temperature loggers. Core temperatures derived from bird no. 1 (sensor placed under the sternum,
in the vicinity of the liver and upper stomach) were closely correlated with diving activity (as determined by an external
light recorder), and ranged from 38.3°C, (on land) to a minimum of 37.2°C during a dive. Core temperatures measured in bird
no. 2 showed that temperatures near the heart were generally 1°C lower than those under the sternum or in the lower abdomen.
Core temperatures declined continuously during dives (by 0.8, 1.2 and 2.7°C in the lower abdomen, under the sternum and near
the heart, respectively) and showed precipitous drops to 35°C, probably associated with ingestion of food. Temperatures measured
near the heart fluctuated over a period of 288 s, corresponding to the duration (from the literature) of the surface/dive
cycle. The relevance of these findings with respect to diving physiology, blood perfusion of tissues, tissue metabolism and
aerobic dive limits is discussed. 相似文献
9.
Phillip A Patten Russell J Howard Willem PC Stemmer 《Current opinion in biotechnology》1997,8(6):724-733
DNA shuffling is a practical process for directed molecular evolution which uses recombination to dramatically accelerate the rate at which one can evolve genes. Single and multigene traits that require many mutations for improved phenotypes can be evolved rapidly. DNA shuffling technology has been significantly enhanced in the past year, extending its range of applications to small molecule pharmaceuticals, pharmaceutical proteins, gene therapy vehicles and transgenes, vaccines and evolved viruses for vaccines, and laboratory animal models. 相似文献
10.
Muriel Bost Mary Berkaw O. Wesley McBride Guy Chazot Philippe Arnaud 《Human genetics》1995,96(2):239-240
Using a probe isolated from a human liver cDNA library, polymorphisms were observed in the human ceruloplasmin gene with the enzymes PstI and MspI. The PstI polymorphism was frequent (allele frequencies, 0.46 and 0.54) whereas the polymorphisms found with MspI were rare. 相似文献