Pulse-chase

After approximately 90 min of anoxia, the induced synthesis of an additional group of c. 20 polypeptides is first detected. This group of 20 anaerobic polypeptides (ANPs) represents more than 70% of the total labelled amino acid incorporation after five hours of anaerobiosis (Fig. 3). By this time the synthesis of the TPs is at a minimal level however, these polypeptides accumulate to a high level during early anaerobiosis and have been shown by pulse-chase experiments to be very stable. The synthesis of... 

Metabolic control analysis (MCA) assigns a flux control coefficient (FCC) to each step in the pathway and considers the sum of the coefficients. Competing pathway components may have negative FCCs. To measure FCCs, a variety of experimental techniques including radio isotopomers and pulse chase experiments are necessary in a tissue culture system. Perturbation of the system, for example, with over-expression of various genes can be applied iteratively to understand and optimize product accumulation. 

Other sand-based systems using COi pulse-chase procedures have been used to produce carbon budgets for Festuca ovina and Plantago lanceolata seedlings (30) and white lupin (Lupimis albiis) (31). Significantly, CO2 pulse labeling of proteoid roots of white lupin under phosphate-deficient conditions showed that high levels of dark fixation of COi by the roots took place and that 66% of this root-fixed carbon was exuded from the roots (31). Clearly, dark fixation of CO2 by roots and subsequent rhizodeposition is an area that deserves further study in the future. 

Two different approaches to the use of C02 labeling have been applied to measure carbon flow within plant-soil systems—pulse-chase and continuous labeling. 

E. A. S. Rattray, E. Paterson, and K. Killham. Characterisation of the dynamics of C-partitioning within Lolium perenne and to the rhizosphere microbial biomass using C pulse chase, Biol. Fertil. Soils 79 280 (1995). 

A useful adjunct is the well-known pulse-chase technique, in which exposure to a radiolabeled compound for a specified period of time (pulse) is followed by the administration of the same compound that is not labeled (chase). 

Another important difference between bistatic and monostatic radar is that a directional receive antenna must scan at a non uniform rate to follow the position of the transmitted signal through space, a process known as pulse chasing. This can be very challenging for designs based upon mechanical scanning and hence an alternative is to use one or more electronically agile beams as in phased array radar. Such phased array antennas can be expensive and in some applications will prohibit the use of the bistatic technique. 

The use of pulse-chase methods identifies differences in the timing and efficiency of absorption between the two pathways, enabling the study of uptake in the endocytosis system [83]. 

In a review of feeding and digestion in the Bivalvia [37], it was proposed that the accumulation of metal-bound particulates in the digestive gland was a two-phase process reflecting extracellular and intracellular digestion, and Viarengo [87] has reached similar conclusions. In a pulse chase study of the uptake of radiolabelled metals (Ag, Cd, Cr, Hg, Se) by the zebra mussel Dreissena... 

In the case of trace metals, adsorption is typically much faster than the time intervals for which it is practically possible to separate the cells. Therefore, in practice, values of kf and kr are most often estimated by assuming that water loss from the hydrated cation is rate-limiting (Eigen-Wilkins mechanism, see Section 4.3.1 above). In some cases, uptake transients can be observed at the start of a short-term uptake experiment or by using pulse-chase experiments for which a metal solution containing a radioactive tracer is replaced by a solution... 

Pleurochrysis carterae Fe 7 x 10-4 3 - 9 x 10-4 Pulse-chase experiment and calculation based upon ka [192]... 

The biosynthesis of myeloperoxidase has been characterised by pulse-chase experiments. This is achieved by incubating cells with a radioactive... 

H]-ethanolamine into PE was inhibited by C6-ceramide in a dose and time-dependent manner (b) delayed disappearance of label from CDP-choline and CDP-ethanolamine in pulse-chase experiments indicated impaired conversion of these CDP-metaboUtes to PC and PE by CPT and EPT, respectively (c) the activities of CPT and EPT are decreased upon C6-ceramide treatment (see Eigure 2 adapted from Bladergroen et al. 1999b). In contrast to BHK cells the activity of CT was not affected significantly in rat-2 fibroblasts by short-chain ceramides. 

A metabolite, molecular entity, or some other event/ process that precedes another component in a longer sequence of events or conversions. For example, the isoprenoid metabolite squalene is a precursor of cholesterol and glucose 6-phosphate is a precursor of glycogen, ribose, and pyruvate. See Series First Order Reaction Pulse-Chase Experiments... 

BASIC PULSE-CHASE KINETICS. For the case of a single pool of A that becomes promptly labeled with tracer A, bolus administration of tracer will initially increase the tracer/tracee ratio (indicated by the initial isotopic enrichment Eo), which will subsequently suffer exponential decay As is the case for all first-order processes, the rate law is ... 

APPLICATIONS OF THE PULSE-CHASE TECHNIQUE. Consideration of a few illustrative cases should serve to underscore the utility of pulse-chase experiments in the characterization of biological systems. 

The amount of material (e.g., macromolecule or metabolite) metabolized or processed per unit time. 2. The balance between synthesis and degradation of a biomolecule. 3. One complete turn of a reaction cycle. See Turnover Number Protein Turnover Pulse-Chase Experiments Exponential Decay... 

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