B cell ligand discrimination through a spreading and contraction response     

Fleire SJ  Goldman JP  Carrasco YR  Weber M  Bray D  Batista FD 《Science (New York, N.Y.)》2006,312(5774):738-741

B cells recognize foreign antigens by virtue of cell surface immunoglobulin receptors and are most effectively activated by membrane-bound ligands. Here, we show that in the early stages of this process, B cells exhibit a two-phase response in which they first spread over the antigen-bearing membrane and then contract, thereby collecting bound antigen into a central aggregate. The extent of this response, which is both signaling- and actin-dependent, determines the quantity of antigen accumulated and hence the degree of B cell activation. Brownian dynamic simulations reproduce essential features of the antigen collection process and suggest a possible basis for affinity discrimination. We propose that dynamic spreading is an important step of the immune response.  相似文献   

A mitotic lamin B matrix induced by RanGTP required for spindle assembly     

Tsai MY  Wang S  Heidinger JM  Shumaker DK  Adam SA  Goldman RD  Zheng Y 《Science (New York, N.Y.)》2006,311(5769):1887-1893

Mitotic spindle morphogenesis is a series of highly coordinated movements that lead to chromosome segregation and cytokinesis. We report that the intermediate filament protein lamin B, a component of the interphase nuclear lamina, functions in spindle assembly. Lamin B assembled into a matrix-like network in mitosis through a process that depended on the presence of the guanosine triphosphate-bound form of the small guanosine triphosphatase Ran. Depletion of lamin B resulted in defects in spindle assembly. Dominant negative mutant lamin B proteins that disrupt lamin B assembly in interphase nuclei also disrupted spindle assembly in mitosis. Furthermore, lamin B was essential for the formation of the mitotic matrix that tethers a number of spindle assembly factors. We propose that lamin B is a structural component of the long-sought-after spindle matrix that promotes microtubule assembly and organization in mitosis.  相似文献   

The structure and catalytic cycle of a sodium-pumping pyrophosphatase     

J Kellosalo  T Kajander  K Kogan  K Pokharel  A Goldman 《Science (New York, N.Y.)》2012,337(6093):473-476

Membrane-integral pyrophosphatases (M-PPases) are crucial for the survival of plants, bacteria, and protozoan parasites. They couple pyrophosphate hydrolysis or synthesis to Na(+) or H(+) pumping. The 2.6-angstrom structure of Thermotoga maritima M-PPase in the resting state reveals a previously unknown solution for ion pumping. The hydrolytic center, 20 angstroms above the membrane, is coupled to the gate formed by the conserved Asp(243), Glu(246), and Lys(707) by an unusual "coupling funnel" of six α helices. Comparison with our 4.0-angstrom resolution structure of the product complex suggests that helix 12 slides down upon substrate binding to open the gate by a simple binding-change mechanism. Below the gate, four helices form the exit channel. Superimposing helices 3 to 6, 9 to 12, and 13 to 16 suggests that M-PPases arose through gene triplication.  相似文献   

Vascular hamartomas of the dorsal carpal region in three young thoroughbred horses   总被引：1，自引：0，他引：1  

CM COLBOURNE  JV YOVICH  RB RICHARDS  KJ ROSE  CR HUXTABLE 《Australian veterinary journal》1997,75(1):20-23

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Production of an interspecific hybrid between Texas and Argentine bluegrass     

J. J. Goldman  P. L. Sims 《Plant Breeding》2005,124(4):419-420

Texas and Argentine bluegrass are both dioecious Poa species with distinct morphological characteristics. Argentine bluegrass has a bunch-type growth habit, fine upright leaves and does not produce rhizomes. Texas bluegrass spreads by rhizomes and has wider, longer leaves. In an effort to produce novel germplasm with forage or turf potential, experiments were conducted to determine whether hybrid seed could be produced. Crosses were made using pollen from an Argentine male to fertilize two Texas female plants. Parents were induced to flower in the greenhouse by extending the photoperiod to 18 h with 400 W high-pressure sodium lamps from late December to April. The two crosses produced >200 seeds each. Hybrid seedlings segregated for traits from both parents. A sorghum-derived SSR marker confirmed the hybrid nature of a group of seedlings. Seeds harvested from F1 plants using Texas or Texas × Argentine pollen lost the undesirable cottony characteristic of Texas bluegrass. Evaluations for forage and turf potential of hybrid and later generation seed are planned.  相似文献   

Biologically active secondary metabolites from Ginkgo biloba     

Bedir E  Tatli II  Khan RA  Zhao J  Takamatsu S  Walker LA  Goldman P  Khan IA 《Journal of agricultural and food chemistry》2002,50(11):3150-3155

Three new compounds, (7E)-2beta,3alpha-dihydroxy-megastigm-7-en-9-one (1), 3-[5,7-dihydroxy-2-(4-methoxyphenyl)-4-oxo-4H-chromen-8-yl]-4-methoxybenzoic acid (2), and 4'-O-methyl myricetin 3-O-(6-O-alpha-L-rhamnopyranosyl)-beta-D-glucopyranoside (3), were isolated from Ginkgo biloba, together with 27 known compounds. The structures of the new compounds were determined primarily from 1D- and 2D-NMR analysis. The 4-O-methylbenzoic acid structural feature at C-8 in 2 is encountered for the first time. The antioxidant activities of 29 compounds isolated from Ginkgo biloba were evaluated on intracellular reactive oxygen species in HL-60 cells. It was found that quercetin, kampferol, and tamarixetin had antioxidant activity that was approximately 3-fold greater than that of their respective glycosides and also approximately 3-fold greater than that of a standard ascorbic acid with an IC(50) at maximum effectiveness.  相似文献   

International Symposium on ‘Environmental disruption—A challenge to social scientists’: held mainly in Tokyo,Japan, 9–16 March, 1970     

Marshall I. Goldman 《Biological conservation》1971

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Lake Baikal: An impending tragedy?     

Marshall I. Goldman 《Biological conservation》1973,5(2):142-143

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BASAL GLAUCONITE AND PHOSPHATE BEDS     

Goldman MI 《Science (New York, N.Y.)》1922,56(1441):171-173

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THE AURORAL DISPLAY OF AUGUST 26     

McDermott FA  Hyde JE  Berry SS  Stover WG  Hessler JC  Latimer HB  Hudelson RR  Zapffe C  Goldman MI  Bevan A  Foster WL  Chapman RH  Jacobs MH 《Science (New York, N.Y.)》1916,44(1141):678-683

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