Population genetics of the population in the European north of the RSFSR. V. An evaluation of the virtual size of the population by computer simulation of marriage and migration processes

The paper deals with the effect of assortative matings on some parameters of population structure. To solve this problem, two rural populations near Archangelsk (river Peosa region) were used. Some genetic and demographic characteristics of these populations were described in previous publications. A comparison between random matches through a random number generator and true marriages was made by computer estimation of the spouses kinship coefficients. Significant avoidance of first and second cousins marriages in real populations was discovered. As a consequence of this avoidance of consanguinity, the effective breeding size of villages is increased twofold. Similar results were obtained by estimation os isonymy.     

Synchronization of calcium channel activity in mollusk neurons after treatment with ferricyanide and barium ions

Using the patch-voltage-clamp method on the isolated membrane patches from molluscan neurons, effects of ferricyanide and barium on fast potassium channels with a priori destroyed synchronism in the transitions between conductance sublevels were studied. Ferricyanide (0.1-0.5 mM) applied at the inner membrane side produced irreversible transformation of occasional transitions of the channel conductance between intermediate states into highly cooperative and potential-dependent process. Barium ions completely or partly reversibly restore synchronism.     

Alamethicin channel kinetics: Studies using fluctuation analysis and multifractal fluctuation analysis

The kinetics of the alamethicine channel incorporated into BLM was studied using detrended fluctuation analysis and multifractal detrended fluctuation analysis. Detrended fluctuation analysis has shown that both the event series formed with dwell times on fixed channel conductivity levels and the event series formed with opened states on all channel conductivity levels are random processes. However, multifractal detrended fluctuation analysis indicated that only dwell times series on fixed channel conductivity levels are random, but the event series formed with opened states on all channel conductivity levels are the correlated multifractal processes.     

Model of multifractal gating of single ionic channels in biological membranes

A physico-mathematical model of the gating machinery of single ionic channels in biological membranes has been developed. In the paradigm of this model, gating particles are subjected to: (i) deterministic friction force responsible for interactions of gating particles with the surrounding solution; (ii) deterministic potential force depending on the structure and conformational state of the channel pore (the latter is controlled by the transmembrane voltage V and regulates the motion of particles overcoming potential barriers on going from the closed (open) to the open (closed) state of the channel); (iii) deterministic force responsible for interactions of water molecules with hydrophobic sites in the channel pore, and, finally, (iv) stochastic thermal fluctuation force. The model affords adequate approximation of experimental data.     

Optimization of genetic constructs for high-level expression of the darbepoetin gene in mammalian cells

Genetic constructs were designed in order to optimize darbepoetin production in CHO cells. They are characterized by a higher level of structural optimization of the darbepoetin gene, a higher gene dose, and the selection of promoter elements that have never been used before for this purpose. A transient transfection of CHO cells by the obtained constructs was performed. It was shown that each of the variable factors in the constructs influenced darbepoetin gene expression. A construct containing a doubled dose of the darbepoetin synthetic gene with optimized codon composition under the control of the CMV-EF1α chimerical promoter was proved to be the most efficient.     

Temperature dependence of kinetic parameters of single potential dependent K+ channels in mollusc neurons. Similarity in the action of potential and temperature]

Using the patch-voltage-clamp method on excised membrane fragments from molluscan neurones temperature dependences of kinetic parameters of the fast and slow K(+)-channels were investigated in the temperature range 1 to 40 degrees C. Temperature dependences of probability of the channel open state (P0) for the slow and fast K(+)-channels are, generally, opposite, that is P0 increases for the slow channel and decreases for the fast channel with temperature. Similar dependences characterize durations of single channel open intervals (tau 0) and burst durations (t(p)). Durations of interburst and interpulse intervals (respectively, t(i) and tau) decrease for the slow channel and increase, in contrast, for the fast channel with temperature. For the channels of both types temperature dependences of P0 (as for other parameters) are essentially nonmonotonous. There are two local extrema, at least: for the slow K(+)-channel-maximum at 15 degrees C (minimum for the fast channel) and minimum at 20-25 degrees C (maximum for the fast channel). In some cases the number of local extrema may be greater than two. Some similarity in the action of temperature and membrane potential on the kinetic parameters was observed. For the slow K(+)-channel P0, tau 0 and t p increase with temperature and membrane potential. For the fast channel these parameters decrease at the same conditions. Moreover, for the channels of both types temperature dependences of the kinetic parameters are slightly pronounced at the potentials where potential dependences of the parameters are least. As a whole, temperature measurements showed that there are, possibly, several points of structural transitions (similar to phase transitions) in the temperature range 0 to 40 degrees C. Primarily, the kinetic parameters are determined by these transitions.     

Activities of elements of the yeast α-factor precursor leader at different stages of somatropin secretion by Saccharomyces cerevisiae

An analytical system for a quantitative assessment of contributions of pre- and pro-components of the yeast α-factor leader to key stages of somatropin secretion in Saccharomyces cerevisiae has been designed. Using this system, it was shown that: 1—the α-factor pro-peptide has contributed almost equally to the secretion at the Erv29p-dependent stage of vesicular transport and at the translocation stage; 2—of the two above stages, the Erv29p-dependent stage could only be optimized by using of two copies of the α-factor pro-peptide; 3—when the α-factor pre-peptide and the artificial pro-peptide with significantly greater hydrophobicity were compared it was found that somatropin secretion apparently depended on the translocation mode as higher secretion was achieved with hydrophobic artificial pre-peptide associated with the co-translational translocation.