Sequential rearrangements of ensemble activity of the putamen neurons of monkeys as a correlate to continuous behavior

Simultaneous recording of unit activity of 6-8 putamen neurons in two monkeys (M. nemestrina and M. mulatta) during performance of the task of alternative spatial choice, was carried out. The extent of rearrangements of the activity in the groups of neurons with the transition from every step of the behavioral program to the next one and the degree of difference in mosaics of reactivity, forming at every step with a different variants of performance, were evaluated using discriminative analysis. The rearrangements of the impulse activity were recorded in all steps of the program. The dynamics of rearrangements with the choice of right or left feeder was different, which resulted in appearance of significant differences in mosaics of reactivity at the stage of decision making and receiving reward. The rearrangements preceding the task-oriented movement of one hand were more pronounced in the contralateral hemisphere. The volume of rearrangements may increase with the performance of movement but the differences of mosaics formed during the movement of right and left hand are decreasing. At the stage of reception of the reward, the rearrangements were greater in case the animal chose the certain (left) feeder irrespective of the side of recording the unit activity.     

Kindling fluorescent proteins for precise in vivo photolabeling

Photobleaching of green fluorescent protein (GFP) is a widely used approach for tracking the movement of subcellular structures and intracellular proteins. Although photobleaching is a powerful technique, it does not allow direct tracking of an object's movement and velocity within a living cell. Direct tracking becomes possible only with the introduction of a photoactivated fluorescent marker. A number of previous studies have reported optically induced changes in the emission spectra of fluorescent proteins. However, the ideal photoactivated fluorescent marker should be a nonfluorescent tag capable of "switching on" (i.e., becoming fluorescent) in response to irradiation by light of a particular wavelength, intensity, and duration. In this report, we generated a mutant of Anemonia sulcata chromoprotein asCP. The mutant protein is capable of unique irreversible photoconversion from the nonfluorescent to a stable bright-red fluorescent form ("kindling"). This "kindling fluorescent protein" (KFP1) can be used for precise in vivo photolabeling to track the movements of cells, organelles, and proteins. We used KFP1 for in vivo cell labeling in mRNA microinjection assays to monitor Xenopus laevis embryo development and to track mitochondrial movement in mammalian cells.     

Effects of ouabain on proliferation of human endothelial cells correlate with Na<Superscript>+</Superscript>,K<Superscript>+</Superscript>-ATPase activity and intracellular ratio of Na<Superscript>+</Superscript> and K<Superscript>+</Superscript>

Side-by-side with inhibition of the Na⁺,K⁺-ATPase ouabain and other cardiotonic steroids (CTS) can affect cell functions by mechanisms other than regulation of the intracellular Na⁺ and K⁺ ratio ([Na⁺]_i/[K⁺]_i). Thus, we compared the doseand time-dependences of the effect of ouabain on intracellular [Na⁺]_i/[K⁺]_i ratio, Na⁺,K⁺-ATPase activity, and proliferation of human umbilical vein endothelial cells (HUVEC). Treatment of the cells with 1-3 nM ouabain for 24-72 h decreased the [Na⁺]_i/[K⁺]_i ratio and increased cell proliferation by 20-50%. We discovered that the same ouabain concentrations increased Na⁺,K⁺-ATPase activity by 25-30%, as measured by the rate of ⁸⁶Rb⁺ influx. Higher ouabain concentrations inhibited Na⁺,K⁺-ATPase, increased [Na⁺]_i/[K⁺]_i ratio, suppressed cell growth, and caused cell death. When cells were treated with low ouabain concentrations for 48 or 72 h, a negative correlation between [Na⁺]_i/[K⁺]_i ratio and cell growth activation was observed. In cells treated with high ouabain concentrations for 24 h, the [Na⁺]_i/[K⁺]_i ratio correlated positively with proliferation inhibition. These data demonstrate that inhibition of HUVEC proliferation at high CTS concentrations correlates with dissipation of the Na⁺ and K⁺ concentration gradients, whereas cell growth stimulation by low CTS doses results from activation of Na⁺,K⁺-ATPase and decrease in the [Na⁺]_i/[K⁺]_i ratio.     

A nanoparticle in plasma

Charge and energy fluxes onto a nanoparticle under conditions typical of laboratory plasmas are investigated theoretically. Here, by a nanoparticle is meant a grain the size of which is much smaller than both the electron Larmor radius and Debye length and the thermionic emission from which is not limited by the space charge. Under conditions at which thermionic emission plays an important role, the electric potential and temperature T _p of a nanoparticle are determined by solving a self-consistent set of equations describing the balance of energy and charge fluxes onto the nanoparticle. It is shown that, when the degree of plasma ionization exceeds a critical level, the potential of the nanoparticle and the energy flux onto it increase with increasing nanoparticle temperature, so that, starting from a certain temperature, the nanoparticle potential becomes positive. The critical degree of ionization starting from which the potential of a nanoparticle is always positive is determined as a function of the plasma density and electron temperature. The nanoparticle temperature T _p corresponding to the equilibrium state of a positively charged nanoparticle is found as a function of the electron density for different electron temperatures.     

Specific features of distribution,ecology, and dynamics of catches of blotched snailfish Crystallichthys mirabilis (Liparidae) in Pacific waters off the northern Kuril Islands and southeastern Kamchatka

Based on materials of 1992–2002, data on the spatial-bathymetric distribution and size-age composition of blotched snailfish Crystallichthys mirabilis and species accompanying it in catches in Pacific waters off the northern Kuril Islands and southeastern Kamchatka are presented. This relatively large representative of the family Liparidae (maximum length in catches 50 cm, body weight 2150 g) is found throughout the examined area in the depth interval of 76–755 m at near-bottom temperature of ?1.2 to +4.2°C. Maximum catches (over 200–500 individuals or 180–280 kg per hour trawling) year round are recorded off the southeastern extremity of Kamchatka, from the oceanic side of the Shumshu and Paramushir islands and on the beam of the Fourth Kuril Strait in the bathymetric range of 151–350 m. The magnitude of its catches in the examined area is subjected to interannual, seasonal, and diurnal dynamics.     

Distribution of cryptic shrew species of the genus Sorex (Mammalia) on the plain between the Don and Kuban rivers as inferred by molecular markers

Microsatellite and mtDNA markers have been used to identify two pairs of cryptic species Sorex araneus L. (Sorex satunini Ogn.) and Sorex minutus L. (S. volnuchini Ogn.). The new data were obtained on the distribution of these species on the plain between the Don and Kuban rivers. The shrew S. volnuchini and Caucasian mole are distributed on the plain areas up to the Eya River. The endemic species of the Caucasus, the shrews S. satunini and S. volnuchini, are widely distributed across the valleys alongside small streams on the steppe plain. Both species are most abundant on thick grasslands, bushy scrub, and deciduous woodlands. They don??t show any clear differences in habitat preferences.     

Na/K Pump and Intracellular Monovalent Cations: Novel Mechanism of Excitation–Transcription Coupling Involved in Inhibition of Apoptosis

The Na/K pump plays a key role in the regulation of the intracellular concentrations of monovalent cations and related cell function leading to electrogenesis and excitation–contraction coupling. We focus this review on the analysis of recent data showing that (i) inhibition of the Na/K pump triggers a signaling cascade independently of modulation of the intracellular [Na⁺]_i/[K⁺]_i ratio; (ii) elevation of [Na⁺]_i under sustained inhibition of the Na/K pump leads to expression of a set of genes by [Ca²⁺]_i-dependent and independent pathways; (iii) [Na⁺]_i-sensitive genes are involved in the inhibition of programmed cell death (apoptosis) in vascular smooth muscle cells.