Self-incompatibility: a self-recognition system in plants   总被引：18，自引：0，他引：18  

V Haring  J E Gray  B A McClure  M A Anderson  A E Clarke 《Science (New York, N.Y.)》1990,250(4983):937-941

Self-incompatibility (SI), a genetically controlled mechanism to prevent inbreeding in plants, offers a relatively simple model system for studying the interactions between plant cells or between a plant cell and the secreted product or products of another cell. Examples of two major types of SI, gametophytic and sporophytic, have been studied by cloning cDNAs corresponding to glycoproteins of the female tissues that segregate with particular variants encoded by the putative S locus. These secreted glycoproteins are envisaged to interact with the currently undescribed pollen component to cause arrest of pollen tube growth.  相似文献   

Binding of SH2 domains of phospholipase C gamma 1, GAP, and Src to activated growth factor receptors   总被引：96，自引：0，他引：96  

D Anderson  C A Koch  L Grey  C Ellis  M F Moran  T Pawson 《Science (New York, N.Y.)》1990,250(4983):979-982

Phospholipase C gamma 1 (PLC gamma 1) and p21ras guanosine triphosphatase (GTPase) activating protein (GAP) bind to and are phosphorylated by activated growth factor receptors. Both PLC gamma 1 and GAP contain two adjacent copies of the noncatalytic Src homology 2 (SH2) domain. The SH2 domains of PLC gamma 1 synthesized individually in bacteria formed high affinity complexes with the epidermal growth factor (EGF)- or platelet derived growth factor (PDGF)-receptors in cell lysates, and bound synergistically to activated receptors when expressed together as one bacterial protein. In vitro complex formation was dependent on prior growth factor stimulation and was competed by intracellular PLC gamma 1. Similar results were obtained for binding of GAP SH2 domains to the PDGF-receptor. The isolated SH2 domains of other signaling proteins, such as p60src and Crk, also bound activated PDGF-receptors in vitro. SH2 domains, therefore, provide a common mechanism by which enzymatically diverse regulatory proteins can physically associate with the same activated receptors and thereby couple growth factor stimulation to intracellular signal transduction pathways.  相似文献   

Linkage of early-onset familial breast cancer to chromosome 17q21   总被引：191，自引：0，他引：191  

J M Hall  M K Lee  B Newman  J E Morrow  L A Anderson  B Huey  M C King 《Science (New York, N.Y.)》1990,250(4988):1684-1689

Human breast cancer is usually caused by genetic alterations of somatic cells of the breast, but occasionally, susceptibility to the disease is inherited. Mapping the genes responsible for inherited breast cancer may also allow the identification of early lesions that are critical for the development of breast cancer in the general population. Chromosome 17q21 appears to be the locale of a gene for inherited susceptibility to breast cancer in families with early-onset disease. Genetic analysis yields a lod score (logarithm of the likelihood ratio for linkage) of 5.98 for linkage of breast cancer susceptibility to D17S74 in early-onset families and negative lod scores in families with late-onset disease. Likelihood ratios in favor of linkage heterogeneity among families ranged between 2000:1 and greater than 10(6):1 on the basis of multipoint analysis of four loci in the region.  相似文献   

Regulation of chloride channels by protein kinase C in normal and cystic fibrosis airway epithelia   总被引：21，自引：0，他引：21  

M Li  J D McCann  M P Anderson  J P Clancy  C M Liedtke  A C Nairn  P Greengard  M J Welsch 《Science (New York, N.Y.)》1989,244(4910):1353-1356

Apical membrane chloride channels control chloride secretion by airway epithelial cells. Defective regulation of these channels is a prominent characteristic of cystic fibrosis. In normal intact cells, activation of protein kinase C (PKC) by phorbol ester either stimulated or inhibited chloride secretion, depending on the physiological status of the cell. In cell-free membrane patches, PKC also had a dual effect: at a high calcium concentration, PKC inactivated chloride channels; at a low calcium concentration, PKC activated chloride channels. In cystic fibrosis cells, PKC-dependent channel inactivation was normal, but activation was defective. Thus it appears that PKC phosphorylates and regulates two different sites on the channel or on an associated membrane protein, one of which is defective in cystic fibrosis.  相似文献   

A single receptor binds both insulin-like growth factor II and mannose-6-phosphate   总被引：23，自引：0，他引：23  

R G MacDonald  S R Pfeffer  L Coussens  M A Tepper  C M Brocklebank  J E Mole  J K Anderson  E Chen  M P Czech  A Ullrich 《Science (New York, N.Y.)》1988,239(4844):1134-1137

Amino acid sequences deduced from rat complementary DNA clones encoding the insulin-like growth factor II (IGF-II) receptor closely resemble those of the bovine cation-independent mannose-6-phosphate receptor (Man-6-P receptorCI), suggesting they are identical structures. It is also shown that IGF-II receptors are adsorbed by immobilized pentamannosyl-6-phosphate and are specifically eluted with Man-6-P. Furthermore, Man-6-P specifically increases by about two times the apparent affinity of the purified rat placental receptor for 125I-labeled IGF-II. These results indicate that the type II IGF receptor contains cooperative, high-affinity binding sites for both IGF-II and Man-6-P-containing proteins.  相似文献   

Simulation of eolian saltation   总被引：4，自引：0，他引：4  

Anderson RS  Haff PK 《Science (New York, N.Y.)》1988,241(4867):820-823

Saltation is important in the transport of sand-sized granular material by wind and in the ejection of dust from the bed both on Earth and on Mars. The evolution of the saltating population and all its characteristic profiles is calculated from inception by pure aerodynamic entrainment through to steady state. Results of numerical simulations of single-grain impacts into granular beds are condensed into analytic expressions for the number and speeds of grains rebounding or rejected (splashed) from the bed. A model is combined with (i) this numerical representation, (ii) an expression for the aerodynamic entrainment rate, and (iii) the modification of the wind velocity profile by saltating grains. Calculated steady state mass fluxes are within the range of mass fluxes measured in wind tunnel experiments; mass flux is nonlinearly dependent on the shear velocity. Aerodynamically entrained grains in the system are primarily seeding agents; at steady state, aerodynamic entrainment is rare. The time for the entire system to reach steady state is roughly 1 second, or several long-trajectory hop times.  相似文献   

Sounding the stratosphere and mesosphere by infrared limb scanning from space   总被引：1，自引：0，他引：1  

Gille JC  Bailey PL  Craig RA  House FB  Anderson GP 《Science (New York, N.Y.)》1980,208(4442):397-399

Inversion of the measurements obtained by the infrared limb scanner on the Nimbus 6 satellite has demonstrated that the stratospheric and mesospheric temperatures and ozone concentrations may be obtained remotely from space with accuracy and precision comparable to in situ methods. Such global data have many applications in middle atmospheric research and operational temperature sounding.  相似文献   

Nimbus-7 coastal zone color scanner: system description and initial imagery     

Hovis WA  Clark DK  Anderson F  Austin RW  Wilson WH  Baker ET  Ball D  Gordon HR  Mueller JL  El-Sayed SZ  Sturm B  Wrigley RC  Yentsch CS 《Science (New York, N.Y.)》1980,210(4465):60-63

The Coastal Zone Color Scanner (CZCS) on Nimbus-7, launched in October 1978, is the only sensor in orbit that is specifically designed to study living marine resources. The initial imagery confirms that CZCS data can be processed to a level that reveals subtle variations in the concentration of phytoplankton pigments. This development has potential applications for the study of large-scale patchiness in phytoplankton distributions, the evolution of spring blooms, water mass boundaries, and mesoscale circulation patterns.  相似文献   

Evidence for chain molecules enriched in carbon, hydrogen, and oxygen in comet halley     

Mitchell DL  Lin RP  Anderson KA  Carlson CW  Curtis DW  Korth A  Rème H  Sauvaud JA  D'Uston C  Mendis DA 《Science (New York, N.Y.)》1987,237(4815):626-628

In situ measurements of the composition and spatial distribution of heavy thermal positive ions in the coma of comet Halley were made with the heavy-ion analyzer RPA2-PICCA aboard the Giotto spacecraft. Above 50 atomic mass units an ordered series of mass peaks centered at 61, 75, 91, and 105 atomic mass units were observed. Each peak appears to be composed of three or more closely spaced masses. The abundances decrease and the dissociation rates increase smoothly with increasing mass. These observations suggest the presence of chain molecules that are enriched in carbon, oxygen, and hydrogen, such as polyoxymethylene (polymerized formaldehyde), in comet Halley.  相似文献   

Site-directed neovessel formation in vivo   总被引：20，自引：0，他引：20  

J A Thompson  K D Anderson  J M DiPietro  J A Zwiebel  M Zametta  W F Anderson  T Maciag 《Science (New York, N.Y.)》1988,241(4871):1349-1352

Angiogenesis is an important component of organogenesis and wound repair and occurs during the pathology of oncogenesis, atherogenesis, and other disease processes. Thus, it is important to understand the physiological mechanisms that control neovascularization, especially with methods that permit the molecular dissection of the phenomenon in vivo. Heparin-binding growth factor-1 was shown to bind to collagen type I and type IV. When complexed with gelatin, heparin-binding growth factor-1 can induce neovascularization at polypeptide concentrations that are consistent with the biological activity of the mitogen in vitro. The adsorption strategy induces rapid blood vessel formation at and between organ- and tissue-specific sites and permits recovery of the site-specific implant for examination and manipulation by molecular methods.  相似文献