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61.
MICROSPECTROFLUOROMETRIC APPROACH TO THE STUDY OF FREE/BOUND NAD(P)H RATIO AS METABOLIC INDICATOR IN VARIOUS CELL TYPES 总被引:3,自引:0,他引:3
Jean-Marie Salmon Elli Kohen† Pierre VIALLET Joseph G. Hirschberg‡Alain W. Wouters‡Cahide Kohen§Bo THORELL 《Photochemistry and photobiology》1982,36(5):585-593
Under excitation at 365 nm, the cell fluorescence is mainly due to bound and free NAD(P)H, plus a small contribution from flavins. Resolution is first attempted in the simplest case. i.e. the increase spectrum (δIf) due to microinjection of glucose-6-phosphate (G6P) into EL2 ascites cells. Above 510 nm, δIF is identical to the spectrum of free NADH. Below 510 nm. the presence of a second component is suggested, i.e. the intensity of the free NADH spectrum is lower than the measured δIF level. The difference between δIf and the free NADH spectrum (maximum at 475 nm) yields a spectrum suggestive of bound NADH with maximum at 450 nm. Thus, with free and bound NADH, the entire δIF can be reconstructed, with some assumptions as to the relative quantum yields of the two components. This seems to leave no place for a flavin component. The questions raised by the lack of such a component are answered using a new microspectrofluorometer, which aiiows correlated monitoring of NAD(P)H and flavins with excitations at 365 and 436 nm, respectively. As detected by excitation at 436 nm, injections of G6P, malate, ADP, and treatments with azide, cyanide or partial anaerobiosis, all indeed show a redox change of flavins, in the sense of decreased emission. It is understandable, however, that such a change which is not very large even using 436 nm excitation should remain undetected when flavins are excited at 365 nm, i.e. using the tail of their excitation spectrum. In contrast to the increased δIF spectrum recorded in response to injected substrate, the initial spectrum (If) of the cell prior to a metabolic perturbation reveals a third component, even with 365 nm excitation. The position and reactivity of this component shows flavin-like properties. The structural resolution attainable makes it possible to obtain the evaluation of free vs. bound NAD(P)H and flavin fluorochromes in the mitochondrial and cytosolic compartments of the intact cell. 相似文献
62.
Pulse radiolysis of deuterated aqueous LiCl glasses at temperatures in the range 6 K to 70 K show that the yield G(e?IR) of infrared absorbing electrons (e?IR) increases sharply as the temperature is lowered when [LiCl] ? 10 M. Under these conditions the yield of visible absorbing electrons (e?vis) decreases, but to a lesser extent. When [LiCl] ? 8 M, G(e?IR) and G(e?vis) are both much less dependent on temperature. These data suggest that at very low temperatures e?IR are not trapped exclusively in a purely aqueous environment. 相似文献
63.
Jo o Batista Lopes Martins Elson Longo Octavio D. Rodr guez Salmon Vicente A.A. Espinoza Carlton A. Taft 《Chemical physics letters》2004,400(4-6):481-486
We have used the Oniom method with three layers in order to study the interaction of CO, H2, H2O, NH3 and CO2 molecules with the ZnO surfaces using a (ZnO)348 cluster model. The layers are divided into the high layer at the CCSD level, the medium layer at the RHF level and the low level layer using the UFF force field method. The orbital and binding energies of the adsorbed molecules, Mulliken and ChelpG charges as well as geometrical parameters were analyzed and compared with the available experimental and theoretical data. 相似文献
64.
A. Bousseksou N. Negre M. Goiran L. Salmon J.-P. Tuchagues M.-L. Boillot K. Boukheddaden F. Varret 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(3):451-456
We report the first study of the effect of a high pulsed magnetic field on a spin transition complex in the solid state. The
high spin fraction was determined by optical reflectivity. Sizeable effects are observed for the well-known spin transition
solid Fe(Phen)2(NCS)2. In the hysteresis loop temperature range, an increase in the HS fraction is obtained, with an irreversible (reversible)
character in the ascending (descending) branch of the loop. The time dependence of the HS fraction provides information on
the kinetics of the spin-crossover process at the spin transition.
Received 23 February 1999 and Received in final form 8 June 1999 相似文献
65.
Interchain bridges of unsaturated double bonds have been proposed to form in amorphous regions, when polyethylene is irradiated in the presence of acetylene. We have corroborated the formation of these bridges by infrared spectroscopic studies. The double bonds are composed mainly of trans-olefin and vinyl end groups, formed as a result of competing radical-radical termination and hydrogen atom abstraction reactions. The hydrogen atom abstraction reaction becomes insignificant in uniaxially oriented high-density polyethylene having a draw ratio of 7.5, because of the alignment and positioning of the initiating radical pairs. During in vacuo irradiation and annealing only in-chain trans-olefins are usually formed. © 1994 John Wiley & Sons, Inc. 相似文献
66.
67.
We present an experimental study of the flow dynamics of a lamellar phase sheared in the Couette geometry. High-frequency ultrasonic pulses at 36 MHz are used to measure time-resolved velocity profiles. Oscillations of the viscosity occur in the vicinity of a shear-induced transition between a high-viscosity disordered fluid and a low-viscosity ordered fluid. The phase coexistence shows up as shear bands on the velocity profiles. We show that the dynamics of the rheological data result from two different processes: (i) fluctuations of slip velocities at the two walls and (ii) flow dynamics in the bulk of the lamellar phase. The bulk dynamics are shown to be related to the displacement of the interface between the two differently sheared regions in the gap of the Couette cell. Two different dynamical regimes are investigated under applied shear stress: one of small amplitude oscillations of the viscosity (
%) and one of large oscillations (
%). A phenomenological model is proposed that may account for the observed spatio-temporal dynamics.Received: 2 December 2003, Published online: 9 March 2004PACS:
83.10.Tv Structural and phase changes - 43.58. + z Acoustical measurements and instrumentation - 47.50. + d Non-Newtonian fluid flows 相似文献
68.
R. Mark Isaac Timothy C. Salmon Arthur Zillante 《International Journal of Game Theory》2005,33(2):287-313
The theory and behavior of the clock version of the ascending auction has been well understood for at least 20 years. The more widely used oral outcry version of the ascending auction that allows bidders to submit their own bids has been the subject of some recent controversy mostly in regard to whether or not jump bidding, i.e. bidders submitting bids higher than required by the auctioneer, should be allowed. Isaac, Salmon & Zillante (2005) shows that the standard equilibrium for the clock auction does not apply to the non-clock format and constructs an equilibrium bid function intended to match with field data on ascending auctions. In this study, we will use economic experiments to provide a direct empirical test of that model while simultaneously providing empirical evidence to resolve the policy disputes centered around the place of jump bidding in ascending auctions.Received: March 2005The authors would like to thank Florida State University for providing the funding for the experiments in this paper and Bradley Andrews for programming assistance. 相似文献
69.
R. J. Abraham F. H. Bottom M. A. Cooper J. R. Salmon D. Whittaker 《Magnetic resonance in chemistry : MRC》1969,1(1):51-56
The 220 MHz 1H spectra of isoverbanone, nopinone and verbanone are reported. The spectra of the first two are completely assigned but that of verbanone only partially. The coupling constants obtained provide information about the conformation of these molecules. The isoverbanone molecule is almost Y shaped, but that of nopinone is between a Y shape and a half-chair conformation with the six membered ring bent away form the gem dimethyl groups. These conformations are consistent with the known steric interactions in these molecules. 相似文献
70.
K.M. Smith P.S.L. Booth H.R. Renshall P.B. Jones G.L. Salmon W.S.C. Williams P.J. Duke W.M. Evans R.E. Hill W.R. Holley D.P. Jones J.J. Thresher 《Nuclear Physics B》1975,91(1):45-53
The slope parameter and its charge asymmetry have been measured for the τ′ decay mode of the charged K mesons. No charge asymmetry in the parameter is observed to the precision level of 1.25%, indicating the absence of CP violating transitions. The result for the slope parameter is consistent with previous measurements and taken with other results on Kπ3 decay modes supports the conclusion that the rule is not exact. 相似文献