Competition between cellular

GOLINI, F., THACH, S.S., BIRGE, C.H., SAFER, B., MERRICK, .C. and THACH, R.E. Competition between cellular and viral mRNAs in vitro is regulated by a messenger discriminatory initiation factor. Proc. Natl. Acad. Sci. U.S.A. (1976), H, 5040-3044-... 

Bablanian et al., 1965, Penman and Summers, 1965). Last, infection with a temperature-sensitive mutant of poliovirus that synthesizes no single-stranded RNA at restrictive temperature nevertheless induces normal inhibition of cellular protein synthesis (Hewlett et al., 1982). All of these results argue against a competition between cellular and viral mRNAs for cellular components as an explanation for the selective inhibition of cellular protein synthesis. A large body of experimental work on this subject has been performed with poliovirus-infected cells, and consequently, the major focus of this review is on the inhibiton of protein synthesis by poliovirus. 

Many unicellular eukaryotes are free-living cells, but may form huge local communities, which are especially beneficial to the homeostasis of the ocean/atmos-phere carbon cycle, e.g. coccoliths. Many others are not free-living, but are extremely valuable in symbiotic relationship with multi-cellular plants and animals. Unfortunately, some unicellular eukaryotes are the causes of disease, for example Trypanosoma, which are animals and cause sleeping sickness in humans (see Section 8.9 for parallel diseases of plants). These facts are reminders that while we consider that the whole ecosystem works to one general purpose (Section 4.4), this does not exclude the obvious feature that within its overall associations we can see diseases inflicted on one species by another or competition between similar species. Many bacteria are also causes of serious eukaryote diseases. Even so at the end of... 

After synthesis, the mRNA exits the nucleus through a nuclear pore and proceeds to the ribosome for translation into protein. Competing with export and translation is the process of message degradation by cellular ribonucleases. The competition between degradation and translation provides another mechanism to regulate the levels of individual messages. 

The basis for this technique lies in the competition between the test antigen and a labelled antigen for the available binding sites on a fixed amount of antibody. While the binding sites are traditionally associated with an antibody, any source of specific reversible binding sites may be used to create an assay in this format. Examples of such are specific transport proteins such as thyroxine-binding globulin and certain cellular receptors such as opiate or benzodiazepine receptors. Under these circumstances the equilibrium mixture may be represented thus ... 

Within the liver there will be competition between acute phase protein and GSH synthesis for the cellular sulphur amino acid pool. The question therefore arises whether incorporation of Cysteine into both of these end-products, during the inflammatory response, is influenced equally by alteration in dietary sulphur amino acid intake... An insufficient intake of sulphur amino acids will thereby exert a pro-inflammatory influence... 

Finally, cell-quota theory treats the entire cellular content of a nutrient as being the pool controlling growth rate (under limiting conditions), and deals with multiple nutrient interactions empirically. At the third level of description, MECHANISTIC models aim to embody realistic accounts of the main biochemical processes and pools within cells. A recent example (Flynn Hipkin, 1999 Flynn, 2001) deals with nitrogen, phosphorus, silicon and iron as well as the carbon content of cells, photosynthesis, and the uptake competition between ammonium and nitrate. However, the model embodies many parameters and there is currently insufficient information to use it to distinguish between groups or species of phytoplankters. Its characteristic nutrient quota parameters are included in Table 9.3 except for those for silicon, which are cell-based. 

Bernlohr and Novelli reported that, although the mechanism of antibiotic synthesis differs from protein synthesis, there appears to be a competition between the two processes for the amino acids available in the cell. During active cellular growth with high protein synthesis, practically no bacitracin was produced. In contrast, bacitracin synthesis was high, when the requirements for protein synthesis were low, as at the end of the log phase or when protein synthesis was inhibited. The production of bacitracin, and some other antibiotics, seems to be related in some way to the sporeforming metabolism . In this phase a great part of the cell wall is dissolved, while protein production remains very low. 

One of the concerns alx)ut studies on the function of particular residues in site-directed mutagenesis is that expressions in some cellular systems lead to competition between P450s 1 lAl and 1 IBl for (adrenodoxin) reducing equivalents in cellular systems". Another issue is that human P450s llBl and 11B2 have been difficult to express in bacteria, so that most experiments have relied on mammalian cells Schizosaccharomyces pombe has provided some success ). Nevertheless, much information about function has been obtained from patients samples . ... 

We interpret the appearance of a frequency in the cellular regime of the traveling N -iso. phase boundary, as resulting from a competition between the nonequilibrium length scale, q, and the equilibrium length scale, qo. 

More rewarding than this difficult probing of the chemical nature of TRF have been a series of experiments dealing with the physiological and cellular mode of action of TRF. A rapid, intravenous injection of TRF produces a striking increase in the plasma levels of TSH within a few seconds (Fig. 4), This can be prevented by pretreatment with thyroxine and there is some sort of a competition between thyroxine and TRF, which we have observed both in vivo and in vitro (4, 21). 

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