排序方式: 共有36条查询结果,搜索用时 328 毫秒
31.
Pearson RA Barber AC Rizzi M Hippert C Xue T West EL Duran Y Smith AJ Chuang JZ Azam SA Luhmann UF Benucci A Sung CH Bainbridge JW Carandini M Yau KW Sowden JC Ali RR 《Nature》2012,485(7396):99-103
Cell transplantation is a potential strategy for treating blindness caused by the loss of photoreceptors. Although transplanted rod-precursor cells are able to migrate into the adult retina and differentiate to acquire the specialized morphological features of mature photoreceptor cells, the fundamental question remains whether transplantation of photoreceptor cells can actually improve vision. Here we provide evidence of functional rod-mediated vision after photoreceptor transplantation in adult Gnat1?/? mice, which lack rod function and are a model of congenital stationary night blindness. We show that transplanted rod precursors form classic triad synaptic connections with second-order bipolar and horizontal cells in the recipient retina. The newly integrated photoreceptor cells are light-responsive with dim-flash kinetics similar to adult wild-type photoreceptors. By using intrinsic imaging under scotopic conditions we demonstrate that visual signals generated by transplanted rods are projected to higher visual areas, including V1. Moreover, these cells are capable of driving optokinetic head tracking and visually guided behaviour in the Gnat1?/? mouse under scotopic conditions. Together, these results demonstrate the feasibility of photoreceptor transplantation as a therapeutic strategy for restoring vision after retinal degeneration. 相似文献
32.
Peptide binding to class I MHC on living cells and quantitation of complexes required for CTL lysis 总被引:17,自引:0,他引:17
Antigenic peptides are presented to CD8+T lymphocytes by class I major histocompatibility complex (MHC) molecules. Peptides specifically bind to purified class I molecules in vitro, and to class I molecules on cells at nonphysiological temperatures. We report here the kinetic and equilibrium parameters for the binding of radiolabelled influenza nucleoprotein peptides (NP-Y365-380 and shorter homologues) to the murine H-2Db molecule on intact, viable cells at 37 degrees C. In contrast to earlier reports, we show that peptide binding is rapid and reversible, with dissociation constants ranging from nanomolar to micromolar, suggestive of typical ligand-receptor interactions. Only 10% of cell-surface Db molecules can bind these peptides. To address the relationship between peptide binding and T-cell recognition of the antigen-MHC complex, we determined the minimum number of complexes required to sensitize a target cell for lysis by class I-restricted cytotoxic T-lymphocytes. Our data indicate that EL4 thymoma cells (H-2b) can be sensitized for lysis by cytotoxic T-lymphocytes when as few as 200 class I-peptide complexes (less than 0.08% of surface Db molecules) are present per cell. 相似文献
33.
Fernández MR Porté S Crosas E Barberà N Farrés J Biosca JA Parés X 《Cellular and molecular life sciences : CMLS》2007,64(11):1419-1427
ζ-crystallins constitute a family of proteins with NADPH:quinone reductase activity found initially in mammalian lenses but
now known to be present in many other organisms and tissues. Few proteins from this family have been characterized, and their
function remains unclear. In the present work, ζ-crystallins from human and yeast (Zta1p) were expressed, purified and characterized.
Both enzymes are able to reduce ortho-quinones in the presence of NADPH but are not active with 2-alkenals. Deletion of the ZTA1 gene makes yeast more sensitive to menadione and hydrogen peroxide, suggesting a role in the oxidative stress response. The
human and yeast enzymes specifically bind to adenine-uracil rich elements (ARE) in RNA, indicating that both enzymes are ARE-binding
proteins and that this property has been conserved in ζ-crystallins throughout evolution. This supports a role for ζ-crystallins
as trans-acting factors that could regulate the turnover of certain mRNAs.
Received 21 February 2007; received after revision 16 April 2007; accepted 23 April 2007
M. R. Fernández, S. Porté: These authors contributed equally to this work. 相似文献
34.
Interaction of bubbles and bacteria in the formation of organic aggregates in sea-water 总被引:1,自引:0,他引:1
R T Barber 《Nature》1966,211(5046):257-258
35.
M. Barber G. J. Elliot R. S. Bordoli B. N. Green B. W. Bycroft 《Cellular and molecular life sciences : CMLS》1988,44(3):266-270
Summary FAB-MS has been applied to the analysis of a nisin complex and FAB-MS and FAB-MS/MS data from the major component used to provide confirmation of the amino sequence and positions of the sulphur-bridged rings in these highly modified peptides. 相似文献
36.
Summary A study of the pituitary of the newt,Notophthalmus viridescens, during limb regeneration indicated no observable changes in histology or ultrastructure of any of the cells of the pars distalis when compared with the pars distalis of unamputated control newts.This investigation supported by a grant from the National Research Council of Canada to S.R. Scadding. 相似文献