Identification of the Channelrhodopsin Genes in the Green and Cryptophytic Algae from the White and Black Seas

Biochemistry (Moscow) - Due to the unique capability of modulating cell membrane potential upon photoactivation, channelrhodopsins of green (Chlorophyta) and cryptophytic (Cryptophyta) algae are...     

Detection of the centriole tyr- or acet-tubulin changes in endothelial cells treated with thrombin using microscopic immunocytochemistry

We used electron microscopic immunocytochemistry to examine the pattern of centriolar staining for tyrosinated or acetylated alpha-tubulin in endothelial cells during short-term incubation with thrombin. Endothelial cells isolated from human aorta (HAEC) and those isolated from umbilical vein (HUVEC) displayed an increase in the intensity of centriolar staining for acet-tubulin within 1 min after thrombin addition. A decrease in the intensity of centriolar staining for tyr-tubulin was detected in HUVEC within 1 min after thrombin addition, while in HAEC centriolar staining for tyr-tubulin became less intense only 5 min later. Mother and daughter centrioles of HUVEC cells displayed different intensity of immunostaining for acet-tubulin and showed no significant variation in the number of subdistal appendages after thrombin addition. Differently, HAEC cells had the same staining pattern of mother and daughter centrioles in both thrombin-untreated and thrombin-treated cultures. A sharp increase in the number of subdistal appendages of mother centriole occurred in HAEC within 5 min of incubation with thrombin. Our findings provided the direct evidence for centrosome involvement in the ligand-mediated signaling events and showed for the first time that ligand-dependent centrosome reorganization includes the centriole per se. Furthermore, based on our observations we would like to propose that MT-nucleating/anchoring properties of the centrosome are subject to rapid regulation by external signals such as thrombin.     

Interleukin-2-dependent regulation of Na/K pump in human lymphocytes

The present study provides the first evidence that the abundance of catalytic alpha1-subunit of Na,K-ATPase increases in the course of T cell blast transformation. Immunodepressant cyclosporin A at anti-proliferative doses diminished the induction of alpha1 protein in activated lymphocytes. Furthermore, in competent T cells, IL-2 increases both the transport activity of Na/K pump and the content of Na,K-ATPase alpha1 protein in a time-dependent manner. A correlation was found between the long-term elevation in ouabain-sensitive Rb influxes and the increase in alpha1 protein content in late activated T cells. These results suggest that (1) the increased expression of Na,K-ATPase proteins underlie the cell cycle-dependent upregulation of ion pump during T cell transformation, and (2) IL-2 is involved in the regulated expression of Na,K-ATPase in human lymphocytes.     

Copper(II) complexes based on a new chelating 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)pyrimidine ligand: Synthesis and crystal structures. Lone pair-π, C-H···π, π-π and C-H···A (A = N, Cl) non-covalent interactions

A new bidentate chelating pyrazolylpyrimidine ligand bearing a strong electron-donating substituent, i.e. 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)pyrimidine (L) (Scheme 1), has been synthesized and used to obtain the copper(II) complexes by reaction with CuCl₂. The molar ratio Cu:L = 1:2 leads to isolation of a complex having CuL₂Cl₂ empirical formula, while the molar ratio Cu:L = 1:1 gives a complex with CuLCl₂ empirical formula. The crystal structure of L as well as the structures of both complexes were studied by single crystal X-ray diffraction. The crystal structure of CuL₂Cl₂ compound is formed by trans-[CuL₂Cl₂] mononuclear molecules. Surprisingly, in contrast to the previous compound having molecular structure, the crystal structure of CuLCl₂ consists of mononuclear [CuL₂Cl]⁺ complex cations and dinuclear [Cu₂Cl₆]²⁻ anions. Thus, formula of CuLCl₂ complex can be represented as [CuL₂Cl]₂[Cu₂Cl₆]. In both complexes molecules of L adopt bidentate chelating coordination mode through N² atom of pyrazole and N³ atom of pyrimidine rings forming five-membered CuN₃C metallocycles. Owing to C-H···N interactions and π-π-stacking L molecules form 2D network. In the structure of trans-[CuL₂Cl₂] there exist double lone pair(N(piperidine))-π(pyrimidine) interactions and C-H···Cl contacts resulting in the formation of 1D chains. Layered 2D structure of [CuL₂Cl]₂[Cu₂Cl₆] results from C-H···Cl, C-H···π and double lone pair(Cl([CuL₂Cl]⁺ complex cation)-π(pyrimidine) interactions.     

Formation of the vascular system of developing bean (Phaseolus limensis L.) seeds according to nuclear magnetic resonance microtomography

1H magnetic resonance microtomography imaging was applied to study vascular systems in developing bean (Phaseolus limensis L.) seeds. Using the gradient echo method, we recorded 2D tomographic sections in the sagittal and axial planes of the fruits sampled from a vegetating plant on days 10, 17, 24, and 31 after fertilization. Any vascular connection between the tissues of maternal plant (bean pod and seed coat) and the embryo were undetectable. The embryo has an autonomous branched network of procambial strands in the cotyledons, converging to the embryonic axis. The bean pods are covered with a network of vascular bundles; large vascular strands run along the dorsal and ventral sutures. The seed coat vascular bundles are formed in the process of seed ripening and are represented by a developed vascular system multiply branching in the middle part of the ground parenchyma at the stage of physiological maturity. They are connected with the source of assimilates via the lateral pod veins and a large vascular bundle, entering the seed below the hilum via the placenta. Assimilates enter the external part of the seed coat, which contains no vascular bundles, via the funiculus vascular bundles and hilum tissue.     

Ergoreflex: The essence and mechanisms

Physical load increases sympathetic nervous activity, which results in an increased cardiac output, constriction of peripheral vessels, and elevated systemic blood pressure. These changes are outcomes of two mechanisms: the central command from cerebral structures that trigger voluntary movements to activate the vasomotor center and the reflexes initiated by mechanical and metabolic changes in a working muscle. The latter mechanism of the sympathetic system activation is termed ergoreflex. The main effects of ergoreflex on the indices of systemic hemodynamics are the following: activation of mechanosensitive afferents mainly leads to inhibition of the tonic vagal effects on the heart, which explains the rapid increase in heartbeats upon loading; activation of chemosensitive afferents comes with some delay in pace with metabolite accumulation in muscles and leads to an increase in efferent sympathetic activity and a rise in blood pressure. The metabolic reflex effect is particularly high in the case of muscle fatigue. This review deals with the mechanisms underlying the ergoreflex and their adaptation to hypodynamia, physical training, and some pathologies.     

Comparison of the aerobic performance of leg and arm muscles in cross-country skiers

In the last fifteen years, a trend has appeared in cross-country ski racing to increase the use of double poling and, therefore, to increase the load on the shoulder girdle (arm) muscles. The purpose of this study was to compare the aerobic performance of elite cross-country skiers in incremental running (treadmill) and double poling (with manual ski ergometer) tests to exhaustion. Four junior cross-country skiers and four biathletes ( $ \dot V_{O_{2max} } $ = 70 (66?C72) mL/min per kg body weight) participated in the experiment. In the double poling test, the lactate concentration increased more rapidly than in the running test, and the peak oxygen consumption ( $ \dot V_{O_{2peak} } $ ) in the double poling test was 88 (84?C93)% of the maximal oxygen consumption ( $ \dot V_{O_{2max} } $ ) in the running test. The relative anaerobic threshold, which characterizes the relative level of current aerobic performance, in the double poling test was significantly lower than in the running test (79 (57?C83)% vs 94 (90?C98)%, respectively). On the basis of these data, it can be concluded that the main reserve for a further increase in the aerobic performance of cross-country skiers and biathletes is the increase in the aerobic capacity of arm and trunk muscles.