Experimental Study of a Vacuum Spark Discharge over a Dielectric Surface

A decrease in the amplitude of the current of a vacuum spark discharge over a dielectric surface with increasing discharge gap length is established. It is shown that, in the presence of a longitudinal magnetic field, the leading edge of the discharge voltage pulse is extended, whereas the clearly pronounced current pulse transforms into a train of alternating current oscillations. The discharge is found to decelerate when the spark is preceded by a low-current discharge.     

Load-dependent release limits the processive stepping of the tetrameric Eg5 motor

Tetrameric motor proteins of the Kinesin-5 family are essential for eukaryotic cell division. The microscopic mechanism by which Eg5, the vertebrate Kinesin-5, drives bipolar mitotic spindle formation remains unknown. Here we show in optical trapping experiments that full-length Eg5 moves processively and stepwise along microtubule bundles. Interestingly, the force produced by individual Eg5 motors typically reached only approximately 2 pN, one-third of the stall force of Kinesin-1. Eg5 typically detached from microtubules before stalling. This behavior may reflect a regulatory mechanism important for the role of Eg5 in the mitotic spindle.     

Reproductive conditions of walleye pollock <Emphasis Type="Italic">Theragra chalcogramma</Emphasis> (Gadidae) off the northeastern coast of Sakhalin Island,Sea of Okhotsk

The spatial distribution of eggs and larvae of the walleye pollock Theragra chalcogramma is considered in respect to dynamics of oceanologic processes, nutrients, chlorophyll а and zooplankton off the northeastern coast of Sakhalin Island in spring 2012. It is shown that the effect of severe temperature regime in the near-bottom horizons in the western Sea of Okhotsk during the spawning period of walleye pollock becomes milder due to specific features of water dynamics. The egg distribution is determined by mesoscale eddies in the region. The species survival depends on the effect of such environmental factors as freshwater discharge from the Amur River, eddy structure in waters of the Sea of Okhotsk, and dynamics of phytoplankton and zooplankton development.     

Biological peculiarities of the industrially bred juvenile Russian sturgeon Acipenser gueldenstaedtii (Acipenseridae, Acipenseriformes) in the Don

We discuss results of the investigation into biological peculiarities of the juvenile Russian sturgeon (Acipenser gueldenstaedtii) from the Aksay-Don Sturgeon Hatchery living in a natural riverine environment and migrating seaward. We supply data on the growth rate, geographic distribution, behavior and the feeding manner of the juvenile Russian sturgeon in the Don. We have estimated the survival rate of the industrially bred juvenile Russian sturgeon living in a natural environment. Apart from the nutritive base in the river and the predation pressure, we found that ecologically and physiologically determined biological characteristics mostly influence the survival rate in the juvenile Russian sturgeon released into the Don. The findings allow estimation of artificial propagation of the Russian sturgeon in the Azov Sea basin.     

Role of STAT3 Transcription Factor in Pathogenesis of Bronchial Asthma

Biochemistry (Moscow) - Bronchial asthma is a heterogeneous chronic inflammatory disease of airways. The studies of molecular and cellular mechanisms of bronchial asthma have established that a...     

Force‐induced globule–coil transition in laminin binding protein and its role for viral–cell membrane fusion

The specific interactions of the pairs laminin binding protein (LBP)–purified tick‐borne encephalitis viral surface protein E and certain recombinant fragments of this protein, as well as West Nile viral surface protein E and certain recombinant fragments of that protein, are studied by combined methods of single‐molecule dynamic force spectroscopy (SMDFS), enzyme immunoassay and optical surface waves‐based biosensor measurements. The experiments were performed at neutral pH (7.4) and acid pH (5.3) conditions. The data obtained confirm the role of LBP as a cell receptor for two typical viral species of the Flavivirus genus. A comparison of these data with similar data obtained for another cell receptor of this family, namely human αVβ3 integrin, reveals that both these receptors are very important. Studying the specific interaction between the cell receptors in question and specially prepared monoclonal antibodies against them, we could show that both interaction sites involved in the process of virus–cell interaction remain intact at pH 5.3. At the same time, for these acid conditions characteristic for an endosome during flavivirus–cell membrane fusion, SMDFS data reveal the existence of a force‐induced (effective already for forces as small as 30–70 pN) sharp globule–coil transition for LBP and LBP–fragments of protein E complexes. We argue that this conformational transformation, being an analog of abrupt first‐order phase transition and having similarity with the famous Rayleigh hydrodynamic instability, might be indispensable for the flavivirus–cell membrane fusion process. Copyright © 2014 John Wiley & Sons, Ltd.     

Peculiarities of Activation of Muscles of the Shoulder Belt in Voluntary Two-Joint Movements of the Upper Limb

We studied coordination of central motor commands (СMCs) coming to muscles of the shoulder and shoulder belt in the course of single-joint and two-joint movements including flexion and extension of the elbow and shoulder joints. Characteristics of rectified and averaged EMGs recorded from a few muscles of the upper limb were considered correlates of the CMC parameters. Special attention was paid to coordination of CMCs coming to two-joint muscles that are able to function as common flexors (m. biceps brachii, caput breve, BBcb) and common extensors (m. triceps brachii, caput longum, TBcl) of the elbow and shoulder joints. Upper limb movements used in the tests included planar shifts of the arm from one spatial point to another resulting from either simultaneous changes in the angles of the shoulder and elbow joints or isolated sequential (two-stage) changes in these joint angles. As was found, shoulder muscles providing movements of the elbow with changes in the angle of the elbow joint, i.e., BBcb and TBcl, were also intensely involved in the performance of single-joint movements in the shoulder joint. The CMCs coming to two-joint muscles in the course of two-joint movements appeared, in the first approximation, as sums of the commands received by these muscles in the course of corresponding single-joint movements in the elbow and shoulder joints. Therefore, if we interpret the isolated forearm movement performed due to a change in the angle of the elbow joint as the main motor event, while the shoulder movement is considered the accessory one, we can conclude that realization of a two-joint movement of the upper-limb distal part is based on superposition of CMCs related to basic movements (main and accessory). Neirofiziologiya/Neurophysiology, Vol. 41, No. 1, pp. 48–56, January–February, 2009.     

Interaction of the anxiolytic agent buspirone with serotonin and other synaptic receptors in the human brain

Buspirone and Mj 138-05 (up to 0.1 mM) did not displace specifically bound (3H) tryptamine, (3H) strychnine, (3H) flunitrazepam and (3H) imipramine in human cortical and hippocampal membrane preparations. At the same time both compounds displayed similar to serotonin affinity (IC50 in the range of 2-6 microM) for (125I)-LSD specific binding sites in the human cortex and hippocamp. IC50 of serotonin and buspirone and Mj 138-05 for (3H) LSD (2 nM) specific binding sites in the hippocamp was determined as 0.14 microM, 2.3 microM and 6.1 microM, respectively; and for (3H) serotonin specific binding sites in the hippocamp as 0.005 microM, 3.8 microM and 21 microM, respectively. The affinity for human cortex (3H) LSD binding sites was 10-fold lower in case of serotonin and 4-fold lower in case of buspirone and Mj 138-05 than in the hippocamp. However, the affinity for (3H) serotonin binding sites in the cortex was the same as in the hippocamp in case of serotonin and 12-15-fold lower than in the hippocamp in case of buspirone and Mj 138-05. It is concluded that in human brain buspirone and Mj 138-05 interact with micromolar affinity with 5 HT2 and are capable of binding to a subpopulation of 5 HT1 receptors in the hippocamp.