Primary structure of the 5.8S gene of rRNA and internal transcribed spacers of rDNA in diploid wheat Triticum urartu thum. ex. gandil

Nucleotide sequences of 5.8S rRNA gene and rDNA internal transcribed spacers ITS-1 and ITS-2 were determined in diploid wheat Triticum urartu. It was shown that 5.8S rRNA gene of this wheat species consists of 163 base pairs and GC-content is 59.5%. When comparing 5.8S rRNA sequences in diploid wheat, rice and lupine and also 5.8S rRNA in hexaploid wheat and horse beans a high evolutional conservatism of its structure was revealed. The size of ITS-1 and ITS-2 in Tr. urartu is 219 and 225 base pairs long correspondingly. While comparing structures of similar rDNA regions of Tr. urartu, rice and maize a high level of homology was found only between nucleotides adjoining genes of high molecular rRNAs. In ITS-1 of Tr. urartu an insertion of 5'-GACGACGACATTGTCCGTC-3' was found, which is absent in maize and rice.     

Enhancement of chloroplast energization in Chlorella by treatments inactivating the nitrate-reducing system

Inactivation of the nitrate-reducing system in whole cells of Chlorella vulgaris Bejerinck by darkening, nitrogen starvation, ammonium, or cycloheximide brings cells into a state with a high yield of the millisecond-delayed fluorescence of chlorophyll. Activation of this system by illumination, by adding glucose to dark-adapted cells or nitrate to nitrogen-starved cells brings the cells into a low-yield state. The transitions between the lowand high-yield state induced by alternating light and dark periods are suppressed by tungstate and restored by subsequent molybdate addition. The drop in the delayed-fluorescence yield upon activation of the nitrate-reducing system is associated with the decrease of the amplitude of the electrochemical proton gradient across the thylakoid membrane of the chloroplast, as evidenced by the kinetics of the light-induced adsorption changes at 520 nm. The decrease of the proton gradient may be caused by the electron flow diverting from the cyclic path in photosystem I as a result of the activation of the electron transfer from ferredoxin to nitrite.Abbreviation DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea     

An Analysis of Phase Relationships between Oscillatory Processes in the Human Cardiovascular System

Biophysics - Abstract—The phase relationships between heart rate variability, respiration, forearm skin blood flow oscillations (according to laser Doppler flowmetry), and finger-pad tissue...     

The poplar ARGOS-LIKE gene promotes leaf initiation and cell expansion,and controls organ size

We identified a Populus nigra auxin-regulated gene involved in organ size (PnARGOS)-LIKE, encoding one organ size related protein in black poplar. It is homologous to AtARGOS and AtARGOS-LIKE genes of Arabidopsis thaliana. ABRE-like, G-box, GATA and I-box motifs were discovered in the promoter region of the poplar ARGOS-LIKE gene. In wild type aspen (Populus tremula) plants, an ortholog of the PnARGOS-LIKE gene (PtrARGOS-LIKE) was noticeably expressed in actively dividing and expanding young leaves and calli, whereas its mRNA content increased in response to exogenous 6-benzylaminopurine, 1-naphthaleneacetic acid, and 24-epibrassinolide. Expression of the PtrARGOS-LIKE gene was reduced under a salinity treatment. In addition, we generated transgenic tobacco and aspen plants with an up-regulated expression of the PnARGOS-LIKE gene. A constitutive expression of the gene contributed to an increase in size of stems and leaves of the transgenic tobacco plants. In the transgenic aspen, a constitutive expression of the PnARGOS-LIKE gene promoted an increase in the frequency of leaf initiations and in leaf length and area. The size of transgenic tobacco and aspen leaves increased due to the enlargement of individual cells. The results show the significance of the PnARGOS-LIKE gene for control of leaf initiation and organ growth by cell expansion in poplar.     

Role of additive stochastic modulation of the heart activity in the formation of 0.1-Hz blood flow oscillations in the human cardiovascular system

In the framework of our previous hypothesis about the participation of structural and hydrodynamic properties of the vascular bed in the formation of the 0.1-Hz component of blood flow oscillations in the human cardiovascular system and on the basis of the reduced hydrodynamic model, the role of additive stochastic perturbations of the operation of the single-chamber pump that simulates the heart was investigated. It was shown that aperiodic noise modulation of the rigidity of the walls of the pump or its valves generates low-frequency oscillations of pressure and blood flow velocity of arterial vascular bed with the maximum amplitude at a frequency close to 0.1 Hz.     

Delivery of CRISPR/Cas Components into Higher Plant Cells for Genome Editing

Russian Journal of Plant Physiology - CRISPR/Cas genome editing of plants is realized in three basic variants, including knockout mutations as indels, insertion of alien DNA fragments, and base...     

Model analysis of the effect of modulated electromagnetic fields with various parameters of modulating signals in cells

A theoretical analysis of the dependence of cell response to modulated electromagnetic fields on the parameters of modulating signals was performed on the basis of the model for calcium-dependent membrane-associated intracellular signaling systems. Expressed amplitude-frequency "windows" in the response of the nonlinear system to external influence were shown to depend on the effective time during which the amplitude of the influencing signal exceeded some threshold value, which is determined by the properties of the system. The presence of negative values in the influencing signal, i.e. the variations in the rate of some process around the inherent value, played an important role for the effect characteristics. The response of the nonlinear system to external influence strongly depended on the waveform of the modulating signal which is determined not only by frequency spectrum, but also by the initial phase of each frequency component. To ensure a regime for the optimal effect, the rates of increase and drop in the modulating signal amplitude should be synchronized with dynamic processes in the biological object being exposed.     

Non-Markovian Gating of Ca2+-Activated K+ Channels in Cultured Kidney Cells Vero. Rescaled Range Analysis

Using the patch-voltage clamp technique and the rescaled range method, activity of single large conductance Ca²⁺-activated K⁺ channels (K_Ca channels) was studied. For the sequences of alternating open and shut time intervals, the dependence R/S vs. N in the double logarithmic coordinates presented a curve with two slopes, H₁ =0.60 ± 0.04, and H₂ = 0.88 ± 0.21, where H₁ and H₂ characterized the Hurst exponents for shot and long time ranges, respectively. Similar results were obtained for reduced data sets consisting of only open or only shut intervals. Randomization of the experimental data resulted in a single slope, H, of 0.52 ± 0.02. Simulations were performed with eight-state Markovian model without memory. The calculated Hurst exponent presented in average 0.54 ± 0.02. The results suggest that the activity of single Ca²⁺-activated K⁺ channel exhibits two regimes, with slight positive correlation at short time ranges (H₁ =0.6), and strong positive correlation at long time ranges (H₂ = 0.88); therefore the channel gating as a whole is not a steady-state Markovian process.