Biomedical subjects

A V Profir

Publications and source records attributed to A V Profir.

3 recordsLinked to original sources

PubMedDate not supplied

[Trigger effect in switching the phage lambda genome].

The paper presents a mathematical model of the trigger switching of lambda phage genome on the basis of the molecular ideas by Ptashne. The sigmoid character of the gene cro promotor was explained via lambda-repressor concentration. The temperature switching of genetic trigger was attributed to the existence of permissive and restrictive temperatures by means of the Fokker-Plank probability density formalism. The dependence of the lambda repressor average concentration of the UV-radiation dose was theoretically calculated. For the lambda phage mutant the hysteresic dependence of the lambda repressor and cro concentrations on the external parameters (for example, UV-intensity) was obtained.

Bacteriophage lambda↗

PubMedDate not supplied

[Trigger mechanism of temperature switching off of Src oncogene TS-mutant in the Georgiev model].

The Georgiev promotor hypothesis about the cutting of cell genome and the latter being subjected to promotor control and virus regulation was used. On its basis the mechanism of temperature switching off of Src oncogene TS-mutant was investigated. It was shown that the model can correlate with the experiment in suggesting the regulating enzyme sigmoid kinetics and the temperature optimum below 35 degrees C. Hysteretic effect allows one to maintain a "healthy" state throughout the temperature switching off.

Genes, Regulator↗

PubMedDate not supplied

[Enzymatic regulatory processes in gene recombination].

Recombination bistability in the system of genetic regulation in pro- and eucaryots is analysed on the basis of sigmoid kinetics of regulatory enzymes. It is shown that under an increase of either exogenic factors (temperature) or endogenic factors (concentration of molecules, which activate the enzymes) of crucial values, bistability solutions for recombination frequencies are possible. Histeresic character of the dependence of this value on the external parameters is pointed out. The role of fluctuation processes in distortion of the memory effects is discussed. On the basis of monostable solutions molecular account for the empiric Plau law is given for U-shaped dependence of recombination frequency on temperature.

Enzymes↗