Sodium-coupled sugar transport: effects on intracellular sodium activities and sodium-pump activity   总被引：2，自引：0，他引：2  

R L Hudson  S G Schultz 《Science (New York, N.Y.)》1984,224(4654):1237-1239

Intracellular sodium activities, (Na)c, were determined in Necturus small intestine before and after addition of galactose to the mucosal bathing solution. In the absence of galactose, (Na)c averaged 12 millimoles per liter. Within 2 minutes after the addition of galactose to the mucosal solution, (Na)c increased to a mean value of 20 millimoles per liter and then declined, in parallel with an increase in transcellular sodium transport, to a value that did not differ significantly from that observed in the absence of the sugar. The final steady state in the presence of galactose was characterized by a three- to fourfold increase in the rate of transcellular Na+ transport in the absence of a significant increase in (Na)c. Thus, the increase in steady-state basolateral pump activity cannot be attributed to an increase in the intracellular sodium transport pool.  相似文献   

Possible tornado-like tracks on Mars     

Grant JA  Schultz PH 《Science (New York, N.Y.)》1987,237(4817):883-885

Distinct atmospheric conditions suggest that dark, ephemeral, filamentary lineations on the martian surface may be formed during the passage of intense atmospheric vortices.  相似文献   

Solid ion-exchange electrode selective for calcium ion   总被引：1，自引：0，他引：1  

F A Schultz  A J Petersen  C A Mask  R P Buck 《Science (New York, N.Y.)》1968,162(850):267-268

A calcium-selective electrode with solid ion exchanger was prepared from a solution of the calcium salt of a dialkylphosphoric acid in collodion. The electrode responds rapidly and reproducibly to activity of calcium ion and demonstrates a selective response for calcium ion in the presence of alkaline earth and alkali metal cations.  相似文献   

A new strategy for the synthesis of glycoproteins     

Zhang Z  Gildersleeve J  Yang YY  Xu R  Loo JA  Uryu S  Wong CH  Schultz PG 《Science (New York, N.Y.)》2004,303(5656):371-373

Posttranslational modifications of proteins regulate many biological processes, including metabolism, signal transduction, and gene expression. The synthetic challenges associated with generating homogeneous populations of selectively modified proteins, however, have hindered detailed studies of the effects of these modifications on protein structure and function. Here, we report an approach to the cotranslational synthesis of selectively glycosylated proteins in which the modified amino acid is genetically encoded. We show that myoglobin containing beta-N-acetylglucosamine (GlcNAc)-serine at a defined position can be expressed in Escherichia coli in good yield and with high fidelity. The beta-GlcNAc moiety can be recognized by a saccharide-binding protein, or subsequently modified with a galactosyltransferase to build more complex carbohydrates. This approach should be generally applicable to other posttranslational modifications such as protein phosphorylation, acetylation, and methylation.  相似文献   

A strategy for probing the function of noncoding RNAs finds a repressor of NFAT   总被引：3，自引：0，他引：3  

Willingham AT  Orth AP  Batalov S  Peters EC  Wen BG  Aza-Blanc P  Hogenesch JB  Schultz PG 《Science (New York, N.Y.)》2005,309(5740):1570-1573

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Selective chemical catalysis by an antibody   总被引：20，自引：0，他引：20  

S J Pollack  J W Jacobs  P G Schultz 《Science (New York, N.Y.)》1986,234(4783):1570-1573

The immunoglobulin MOPC167, which binds the transition state analog p-nitrophenylphosphorylcholine with high affinity, catalyzed the hydrolysis of the corresponding carbonate 1. MOPC167 catalysis displayed saturation kinetics with catalytic constant (kcat) = 0.4 min-1 and Michaelis constant (Km) = 208 microM, showed substrate specificity, and was inhibited by p-nitrophenylphosphorylcholine. The rate of the reaction was first order in hydroxide ion concentration between pH 6.0 and 8.0. The lower limit for the rate of acceleration of hydrolysis by the antibody above the uncatalyzed reaction was 770. This study begins to define the rules for the generation of catalytic antibodies.  相似文献   

Requirement of Cks2 for the first metaphase/anaphase transition of mammalian meiosis     

Spruck CH  de Miguel MP  Smith AP  Ryan A  Stein P  Schultz RM  Lincoln AJ  Donovan PJ  Reed SI 《Science (New York, N.Y.)》2003,300(5619):647-650

We generated mice lacking Cks2, one of two mammalian homologs of the yeast Cdk1-binding proteins, Suc1 and Cks1, and found them to be viable but sterile in both sexes. Sterility is due to failure of both male and female germ cells to progress past the first meiotic metaphase. The chromosomal events up through the end of prophase I are normal in both CKS2-/- males and females, suggesting that the phenotype is due directly to failure to enter anaphase and not a consequence of a checkpoint-mediated metaphase I arrest.  相似文献   

Oak leaf quality declines in response to defoliation by gypsy moth larvae     

Schultz JC  Baldwin IT 《Science (New York, N.Y.)》1982,217(4555):149-151

Leaves of red oak trees that had been defoliated by gypsy moth larvae during the previous year and again during the period of the study had higher values of tanning coefficients, total phenolics, hydrolyzable and condensed tannins, dry matter contents, and toughness than did leaves of undamaged trees. These changes may influence larval growth and alter the course of further outbreaks.  相似文献   

THE FERMENTATION TEST FOR VITAMIN B1     

Schultz AS  Atkin L  Frey CN 《Science (New York, N.Y.)》1938,88(2293):547

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Planetary science. Hidden Mars     

Schultz PH 《Science (New York, N.Y.)》2007,318(5853):1080-1081

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