Cyclic urinary leukopoietic activity in gray collie dogs   总被引：6，自引：0，他引：6  

C H Brown  D C Dale  P Carbone  S M Wolff 《Science (New York, N.Y.)》1971,173(992):152-153

The urinary activities for bone marrow colony formation were measured on consecutive 24-hour urine samples from two gray collie dogs with cyclic neutropenia and from two normal collies. The activity varied cyclically in the gray collies with a peak activity developing during the neutropenic phase, which antecedes the return of blood neutrophils. The activity fell to undetectable levels after the blood neutrophil counts returned to the normal range. The urine of normal dogs showed no activity. Since the dogs with cyclic neutropenia have been shown to have periodic hematopoiesis, these data suggest a regulatory hormonal role for the substance measured by this assay.  相似文献   

Ability of the Bobwhite to Grow and Reproduce without a Dietary Source of Vitamin B12     

Dale FH 《Science (New York, N.Y.)》1955,121(3149):675-676

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ADDRESS OF THE PRESIDENT OF THE ROYAL SOCIETY     

Dale H 《Science (New York, N.Y.)》1944,100(2585):17-22

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CO2 elicits long-term decline in nitrogen fixation     

Hungate BA  Stiling PD  Dijkstra P  Johnson DW  Ketterer ME  Hymus GJ  Hinkle CR  Drake BG 《Science (New York, N.Y.)》2004,304(5675):1291

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Islet regeneration during the reversal of autoimmune diabetes in NOD mice     

Kodama S  Kühtreiber W  Fujimura S  Dale EA  Faustman DL 《Science (New York, N.Y.)》2003,302(5648):1223-1227

Nonobese diabetic (NOD) mice are a model for type 1 diabetes in humans. Treatment of NOD mice with end-stage disease by injection of donor splenocytes and complete Freund's adjuvant eliminates autoimmunity and permanently restores normoglycemia. The return of endogenous insulin secretion is accompanied by the reappearance of pancreatic beta cells. We now show that live donor male or labeled splenocytes administered to diabetic NOD females contain cells that rapidly differentiate into islet and ductal epithelial cells within the pancreas. Treatment with irradiated splenocytes is also followed by islet regeneration, but at a slower rate. The islets generated in both instances are persistent, functional, and apparent in all NOD hosts with permanent disease reversal.  相似文献   

PHYSIOLOGY OF THE NERVOUS SYSTEM     

Dale HH 《Science (New York, N.Y.)》1939,90(2339):393-394

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Cell-to-cell transfer of bacterial outer membrane lipoproteins     

Nudleman E  Wall D  Kaiser D 《Science (New York, N.Y.)》2005,309(5731):125-127

Myxococcus xanthus cells can glide forward by retracting type IV pili. Tgl, an outer membrane lipoprotein, is necessary to assemble pili. Tgl mutants can be transiently "stimulated" if brought into end-to-end contact with tgl+ donor cells. By separating the stimulated recipient cells from donor cells, we found that Tgl protein was transferred from the donors to the rescued recipient cells. Mutants lacking CglB lipoprotein, which is part of a second gliding engine, could also be stimulated, and CglB protein was transferred from donor to recipient cells. The high transfer efficiency of Tgl and CglB proteins suggests that donor and recipient cells briefly fuse their outer membranes.  相似文献   

The Arabidopsis circadian clock incorporates a cADPR-based feedback loop     

Dodd AN  Gardner MJ  Hotta CT  Hubbard KE  Dalchau N  Love J  Assie JM  Robertson FC  Jakobsen MK  Gonçalves J  Sanders D  Webb AA 《Science (New York, N.Y.)》2007,318(5857):1789-1792

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Chimeras of two isoprenoid synthases catalyze all four coupling reactions in isoprenoid biosynthesis     

Thulasiram HV  Erickson HK  Poulter CD 《Science (New York, N.Y.)》2007,316(5821):73-76

The carbon skeletons of over 55,000 naturally occurring isoprenoid compounds are constructed from four fundamental coupling reactions: chain elongation, cyclopropanation, branching, and cyclobutanation. Enzymes that catalyze chain elongation and cyclopropanation are well studied, whereas those that catalyze branching and cyclobutanation are unknown. We have catalyzed the four reactions with chimeric proteins generated by replacing segments of a chain-elongation enzyme with corresponding sequences from a cyclopropanation enzyme. Stereochemical and mechanistic considerations suggest that the four coupling enzymes could have evolved from a common ancestor through relatively small changes in the catalytic site.  相似文献   

Contributions of two types of calcium channels to synaptic transmission and plasticity   总被引：7，自引：0，他引：7  

B Edmonds  M Klein  N Dale  E R Kandel 《Science (New York, N.Y.)》1990,250(4984):1142-1147

In Aplysia sensory and motor neurons in culture, the contributions of the major classes of calcium current can be selectively examined while transmitter release and its modulation are examined. A slowly inactivating, dihydropyridine-sensitive calcium current does not contribute either to normal synaptic transmission or to any of three different forms of plasticity: presynaptic inhibition, homosynaptic depression, and presynaptic facilitation. This current does contribute, however, to a fourth form of plasticity--modulation of transmitter release by tonic depolarization of the sensory neuron. By contrast, a second calcium current, which is rapidly inactivating and dihydropyridine-insensitive, contributes to release elicited by the transient depolarization of an action potential and to the other three forms of plasticity.  相似文献