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91.
92.
Hanne Gahéry-Ségard Evelyne Jouvin-Marche Adrien Six Carine Gris-Liebe Marie Malissen Bernard Malissen Pierre-André Cazenave Patrice N. Marche 《Immunogenetics》1996,44(4):298-305
The number of mouse Tcra-V gene segments varies from one individual to another and is estimated to be about 100. Southern blot analysis revealed that
most of the Tcra-V are organized in clusters composed of copies of Tcra-V belonging to different subfamilies. We analyzed in detail a Tcra-V subfamily and looked for new Tcra-V in order to improve the knowledge of the mouse Tcra locus organization. A series of genomic clones derived from the B10.A mouse strain enclosing these clusters was used to determined
the structure of all the Tcra-V2. We were able to identify ten Tcra-V2. This study showed that the Tcra-V2 can be organized into three structural subgroups. The distribution of the genes along the Tcra locus, plus their structural organization, indicates that successive duplications occurred during the processes of expansion
and contraction of the Tcra-V gene subfamilies. Several Tcra-V2 are also identical, indicating recent duplications. The most divergent Tcra-V2 differ by 7.4% nucleotides, leading to 5.2% differences in amino acid contents.
Received: 8 August 1995 / Revised: 24 April 1996 相似文献
93.
94.
Homogeneously purified poly(ADP-ribose) polymerase (PARP) specifically stimulated the activity of immunoaffinity-purified calf or human DNA polymerase by about 6 to 60-fold. Apparently, poly(ADP-ribosyl)ation of DNA polymerase was not necessary for the stimulation. The effects of PARP on DNA polymerase were biphasic: at very low concentrations of DNA, it rather inhibited its activity, whereas, at higher DNA concentrations, PARP greatly stimulated it. The autopoly(ADP-ribosyl)ation of PARP suppressed both its stimulatory and inhibitory effects. By immunoprecipitation with an anti-DNA polymerase antibody, it was clearly shown that PARP may be physically associated with DNA polymerase . Stimulation of DNA polymerase may be attributed to the physical association between the two, rather than to the DNA-binding capacity of PARP, since the PARP fragment containing only the DNA binding domain showed little stimulatory activity. The existence of PARP-DNA polymerase complexes were also detected in crude extracts of calf thymus. 相似文献
95.
Juana J. Perdomo Pierre Gounon Madeleine Schaeverbeke Jean Schaeverbeke Vanina Groult Marie P. Jacob Ladislas Robert 《Journal of cellular physiology》1994,158(3):451-458
Mesenchymal cells (fibroblasts, smooth muscle cells) and endothelial cells were shown to interact with elastin fibers. The strong adhesion of elastin fibers to these cells is mediated by a cell membrane complex with a major glycoprotein component of 120 kDa designated as elastonectin. This interaction was studied by transmission electron microscopy (TEM) and immunocytochemical techniques using antibodies raised against the elastin adhesive proteins. When fibroblasts and smooth muscle cells were cultured in presence of elastin fibers, TEM showed an adhesion mechanism that takes place over several sites along the plasma membrane of these cells. Endothelial cells showed a very close association with elastin, emitting “pseudopodia” that embody the fibers. TEM, indirect immunofluorescence, immunoperoxidase, and confocal microscopy showed the presence and localization of cell membrane components synthesized in large quantities when cells were incubated in presence of elastin. Cells without elastin fibers barely revealed the adhesive membrane complex. These results confirm and extend previous findings concerning the presence of an inducible cell membrane complex that mediates the adhesion of elastin fibers to these cell types. © 1994 Wiley-Liss, Inc. 相似文献
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98.
Beatriz Ernestina Cabilio Guth Eliana Gonalves Aguiar Patricia Marie Griffin Sonia Regina Testa da Silva Ramos Tnia Aparecida Tardelli Gomes 《Microbiology and immunology》1994,38(9):695-701
Fifty-eight enterotoxigenic Escherichia coli (ETEC) strains, isolated from children with and without diarrhea in Sao Paulo, were examined for the presence of colonization factor antigens (CFAs) and their ability to adhere to HeLa cells. Antisera to CFA/I, the coli surface (CS) antigens CS1CS3, CS2CS3, and CS2 of CFA/II, CFA/III, and CS5CS6 and CS6 of CFA/IV were used. CFAs were identified in 43% of the ETEC strains: 40% of the strains with CFAs harbored CFA/I, 24% carried CFA/II (CS1CS3), 24% carried CFA/IV (CS6), and 12% carried CFA/IV (CS5CS6). CFAs occurred mainly among ETEC strains producing only heat-stable (ST-I) enterotoxin and in strains also producing heat-labile toxin (LT-I). No ETEC strains tested expressed CFA/III. A marked change in serotypes of ST-I-producing strains was found in Sao Paulo between 1979 and 1990. Adherence to HeLa cells was detected in 14% of the ETEC strains. All of them had a diffuse adherence pattern and produced only ST-I, and 88% carried CS6 antigen. 相似文献
99.
Many studies have reported on the dental status of elderly patients. The results demonstrate consistent differences between normative and perceived needs in addition to varying levels of awareness of dental education among carers. This review article attempts to integrate a range of social factors which must be considered if holistic and comprehensive care is to be delivered to elderly patients. 相似文献
100.
Muhammad W. Raza C. Caroline Blackwell Marie M. Ogilvie Abdulrahman T. Saadi John Stewart Robert A. Elton Donald M. Weir 《FEMS immunology and medical microbiology》1994,10(1):25-30
Abstract Viral glycoproteins G and F are expressed on the surface of cells infected with respiratory syncytial virus (RSV). We investigated the role of these proteins in the previously reported enhanced binding of Neisseria meningitidis to RSV-infected HEp-2 cells. Virus particles attached to bacteria were detected by immunofluorescence with flow cytometry. Binding of FITC-labelled bacteria to RSV-infected cells was significantly inhibited by monoclonal antibody against glycoprotein G. Unlabelled bacteria interfered with binding of the anti-G monoclonal antibody to these cells. These interactions were not found with a monoclonal antibody against glycoprotein F. We propose that glycoprotein G of RSV expressed on the surface of infected cells might act as an additional receptor for meningococci. 相似文献