Human 4E-T represses translation of bound mRNAs and enhances microRNA-mediated silencing

A key player in translation initiation is eIF4E, the mRNA 5′ cap-binding protein. 4E-Transporter (4E-T) is a recently characterized eIF4E-binding protein, which regulates specific mRNAs in several developmental model systems. Here, we first investigated the role of its enrichment in P-bodies and eIF4E-binding in translational regulation in mammalian cells. Identification of the conserved C-terminal sequences that target 4E-T to P-bodies was enabled by comparison of vertebrate proteins with homologues in Drosophila (Cup and CG32016) and Caenorhabditis elegans by sequence and cellular distribution. In tether function assays, 4E-T represses bound mRNA translation, in a manner independent of these localization sequences, or of endogenous P-bodies. Quantitative polymerase chain reaction and northern blot analysis verified that bound mRNA remained intact and polyadenylated. Ectopic 4E-T reduces translation globally in a manner dependent on eIF4E binding its consensus Y³⁰X₄Lϕ site. In contrast, tethered 4E-T continued to repress translation when eIF4E-binding was prevented by mutagenesis of YX₄Lϕ, and modestly enhanced the decay of bound mRNA, compared with wild-type 4E-T, mediated by increased binding of CNOT1/7 deadenylase subunits. As depleting 4E-T from HeLa cells increased steady-state translation, in part due to relief of microRNA-mediated silencing, this work demonstrates the conserved yet unconventional mechanism of 4E-T silencing of particular subsets of mRNAs.     

Restriction mapping of genetic transfer factor pAP39

A model of calculation of molecular weights of fragments EcoRI, Hind III and PvuI is formulated. A restriction site map of factor pAP39 is constructed automatically. Sites to EcoRI and PvuI are distributed in the segment with molecular weight 9.1 MD.     

Local Anesthetics Affect Gramicidin A Channels via Membrane Electrostatic Potentials

The effects of local anesthetics (LAs), including aminoamides and aminoesters, on the characteristics of single gramicidin A (GA) channels in 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) bilayers were studied. Aminoamides, namely lidocaine (LDC), prilocaine (PLC), mepivacaine (MPV), and bupivacaine (BPV), reduced the conductance of GA channels. Aminoesters influenced the current fluctuations induced by GA differently; procaine (PC) did not affect the fluctuations, whereas tetracaine (TTC) distinctly reduced the conductance of single GA channels. Using electrophysiological technique, we estimated the changes in the membrane boundary potential at the adsorption of LAs; LDC, PLC, MPV, BPV, and TTC substantially increased, while PC did not affect it. To elucidate which component of the membrane boundary potential, the surface or dipole potential, is responsible for the observed effects of LAs, we employed a fluorescence assay. We found that TTC led to a significant increase in the membrane dipole potential, whereas the adsorption of LDC, PLC, MPV, BPV, and PC did not produce any changes in the membrane dipole potential. We concluded that aminoamides affected the surface potential of lipid bilayers. Together, these data suggest that the effects of LAs on the conductance of single GA channels are caused by their influence on membrane electrostatic potentials; the regulation of GA pores by aminoamides is associated with the surface potential of membranes, whereas TTC modulation of channel properties is predominantly due to changes in dipole potential of lipid bilayers. These data might provide some significant implications for voltage-gated ion channels of cell membranes.     

Effect of single neonatal melatonin treatment on in vitro thyroxin secretion and TSH or melatonin-modified cAMP level of one-month-old rats

At the age of one month, incubation with melatonin of the thyroid glands of rats having received a single melatonin treatment at the age of three days resulted in increased thyroxine production. TSH was unable to enhance the thyroxine production of animals treated with melatonin neonatally, while its considerable increase could be observed in the case of control animals. Simultaneous TSH and melatonin treatment applied in vitro at the age of one month resulted in an approximately twofold increase of thyroid T4 production in rats having received neonatal melatonin treatment. In vitro alteration of the cyclic AMP level of the thyroid glands of intact and neonatally melatonin treated rats ran practically parallel, except that in the melatonin treated animals the cAMP level was higher after TSH administration. At the same time the cAMP level decreased in the thyroid gland of animals treated with TSH + melatonin. There was no exact correlation between the alterations of cAMP and T4 levels in the given experimental system.     

Intralymphatic administration of antibiotics in the complex treatment of suppurative complications in patients with neurosurgical pathology

The efficacy of endolymphatic route of gentamicin and ceporin administration was studied in 89 patients with neurosurgical pathological processes complicated by acute pneumonia (80 patients) and meningoencephalitis (9 patients) usually after ineffective antibiotic therapy according to the routine methods. The antibiotics were used in accordance with the antibiograms of the causative agents isolated from the bronchial tree or CSF. The endolymphatic use of gentamicin or ceporin once a day in doses of 80 mg or 1 g respectively provided rapid sanation and arresting of the inflammatory foci, lowering of the intoxication level, more rapid promotion of the positive time course of the clinico-roentgenological and laboratory indices and decreasing of the recovery periods by 1.5-2 times in 86 per cent of the patients with pneumonia. The endolymphatic administration of gentamicin in a dose of 80 mg twice a day or ceporin in a dose of 1 g twice a day allowed one to maintain the antibiotic therapeutic levels in the cerebrospinal fluid and to obtain satisfactory clinical results in the combined treatment of meningoencephalitis. The endolymphatic administration of the drugs was well tolerated by the patients and no adverse reactions were observed. This route of administration of antibiotics and in particular broad spectrum antibiotics may be recommended for urgent antibacterial therapy of especially severe neurosurgical patients with pyo-inflammatory complications and patients who did not respond to the routine antibiotic therapy.     

Laser spatial scanning in flow cytometry]

The main flow laser cytometry principles, based on the elastic light scattering, spheres of its applications, problems of its realization and utilization in the immunological investigations and diagnostics are analysed. The experimental model of a flow cytometer with laser probing beam space scanning, originally proposed by the authors, is described. The apparatus was tested by polystyrene latex spheres and biological objects. The experiments showed that the achieved sensitivity was enough to register red blood cells, their complexes and bacterial cells.