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R N Tchuraev

Publications and source records attributed to R N Tchuraev.

6 recordsLinked to original sources
PubMed2000

Epigenes: design and construction of new hereditary units.

A plasmid digene construction designed before [Tchuraev, R.N. (1982) J. Gen. Biol. 43, 79-87] has been realised, including feedback by repressing proteins with given trigger regime of gene functioning. Experimental tests of the expected epigene properties of the obtained pECPI recombinant plasmid involving lacI and cI(857) regulatory genes have shown a phenomenon of steady inheritance of two alternative epigenotypes lacI(1)cI(0) and lacI(0)cI(1), as well as an external toggle switch through metabolitic and temperature signals from one inherited functional state of the cyclic digene system into another. Thus, we have constructed a hereditary unit of a specific kind, namely, a two-component stationary epigene with preset properties.

Bacterial Proteins↗
PubMed1991

A new method for the analysis of the dynamics of the molecular genetic control systems. I. Description of the method of generalized threshold models.

In the molecular system of coding polymers and metabolites a control subsystem has been singled out that forms controlling variables showing the action of regulatory molecules and a controlled subsystem where, depending on the values of controlling variables controlled variables are formed, i.e. concentrations of DNA, m-RNA, proteins and metabolites. Relationships have been obtained which enable controlling variables to be found. Equations showing the dynamics of molecular genetic control systems' components have been obtained. A method of generalized threshold models that enables kinetic curves to be obtained by pure mathematical means for macromolecular components (DNA, RNA, proteins) of molecular genetic control systems of varying complexity is suggested.

Animals↗
PubMed1991

A new method for the analysis of the dynamics of the molecular genetic control systems. II. Application of the method of generalized threshold models in the investigation of concrete genetic systems.

Mathematical models of the prokaryotic control systems of tryptophan biosynthesis (both normal and with cloned blocks) and arabinose catabolism have been built using the method of generalized threshold models. Kinetic curves for molecular components (mRNAs, proteins, metabolites) of the systems considered are obtained. It has been shown that the method of generalized threshold models gives a more detailed qualitative picture of the dynamics of the molecular genetic control systems in comparison with the heuristic method of threshold models. The qualitative analysis of the functioning of the following mechanisms of control of the tryptophan biosynthesis: (1) inhibition of the activity of anthranilate synthetase by tryptophan, (2) repression and (3) attenuation of transcription of the tryptophan operon on the basis of the mathematical model of the control system of the tryptophan biosynthesis demonstrates that feedback inhibition is the most operative of the considered mechanisms while repression allows the bacterium to economize intracellular resources. As regards the control system of the arabinose catabolism the results of modelling enable us to state the following. The induction by arabinose within a wide range of parameter values causes two subsystems (araBAD and transport operons) of the arabinose regulon with a low rate of arabinose utilization to pass into a stationary regime and one subsystem (araC operon) to pass into a stable periodical regime. A study of the system characterized by the effective utilization of arabinose has shown that under induction by arabinose stable oscillations with small amplitudes of the concentration of regulatory protein and oscillations with large amplitudes of the concentrations of arabinose-isomerase and transport protein may occur. The period of the oscillation depends on the mean lifetime of the "activator-DNA" complex and on the rate constant of arabinoseisomerase degradation.

Animals↗