[Disordered regions in C-domain structure of influenza virus M1 protein].

Influenza virus matrix M1 protein is one of the main structural components of the virion performing also many different functions in infected cell. X-ray analysis data with 2.08 angstrom resolution were obtained only for the N-terminal part of M1 protein molecule (residues 2-158) but not for its C-terminal domain (159-252). In the present work M1 protein of A/Puerto Rico/8/34 (H1N1) virus strain in acidic solution was investigated with the help of tritium bombardment. Tritium label incorporation into M1 protein domains preferentially labeled the C-domain and inter-domain loops. Analytical centrifugation and dynamic light scattering experiments demonstrated increased hydrodynamic parameters (diameter) that may be explained by low degree of M1 structural organization. Computational analysis of M1 protein by intrinsic disorder predictions methods also demonstrated the presence of unfolded regions mostly in the C-domain and inter-domain loops. It is suggested, that influenza virus M1 polyfunctionality in infected cell is determined by its tertiary structure plasticity which in its turn results from the presence of unstructured regions.

[The concept of transmembrane asymmetry of lateral domains in biomemranes and influenza virus envelope fine structure].

The molecular architectures of enveloped viruses are one demonstrative example of perfectly arranged macromolecular complex that is achieved through the structural specificity of virus assembly. Virus morphogenesis is a multi-step process that depends on the concerted actions of many viral and cellular components as well as fitted organization of main viral constituents. Viral envelope was shown to be composed of the mixture of lipid raft and non-raft domains. The domains are recruited from the host-cell membrane as discrete well-ordered lipid-protein units in the process of virus assembly. Raft-like nature of influenza virus A envelope was visualized using a novel approach of cold solubilization of the detergent-resistant membranes from intact influenza virus A virions with the mixture of two non-ionic detergents drastically differing in their raft-solubilizing activities, NP40 and octyl-glucopyranoside. In the view of this methodological approach, the virus envelope is apparently an ensemble of platforms which are flexibly joint in the viral envelope, and composed of surface glycoproteins (hemagglutinin and neuraminidase), matrix M1 protein and lipids. The modern concept of transmembrane asymmetry of lateral domains in biological membranes was involved to explain the solubilization mechanism revealed. Using principles of this concept we suggest matrix M1 protein shell as a structure-forming base to support asymmetrical rafts in the virus envelope.

[Determination of concentration and aggregate size in influenza virus preparations using the true UV-absorption spectra].

It is well-known that influenza virus (IV) preparations are characterized by very large contribution of light-scattering to their UV absorption spectra. With the help of so called extrapolation method we managed to measure true absorption spectra of IV preparations and to determine absorption coefficients (E0.1(1) (cm, 280)) for the intact IV virions and for IV subviral particles. These coefficients turned out to equal 1.26 +/- 0.17 and 0.96 +/- 0.11 for the virions and subviral particles respectively. The knowledge of exact IV concentration is necessary for quantitative physico-chemical studies of IV virions and their components. It is also shown that UV absorption spectra measurements allow to register IV virion aggregation. Aggregation properties of IV subviral particles were also studied.

[Dependence of kinetic constants of intact human lymphocyte beta2-adrenoreceptors on the nature of the radioligands used]. / Zavisimost' kineticheskikh konstant beta2-adrenoretseptorov intaktnykh limfotsitov cheloveka ot prirody primeniaemykh radioligandov.

An analysis of human peripheral blood intact mononuclear lymphocyte beta 2-adrenoreceptors showed that the hydrophilic radioligand 3H-CGP-12177 binds at various temperatures only to surface receptors. The density of receptors as determined by the binding of the lipophilic antagonist 125I-CYP at 37 degrees C is 2 times as high as that at 4 degrees C. The affinity of lymphocyte beta 2-adrenoceptors for 1-isoproterenol measured by the labeled ligand displacement at low (4 degrees C) temperatures is by two or three orders of magnitude higher than that at 37 degrees C. The thiol-alkylating agent, N-ethylmaleimide (NEM) causes oppositely directed changes in the density of beta 2-adrenoceptors on intact lymphocytes depending on their original density. NEM increases the affinity of beta 2-adrenoreceptors for the hormone (1.5-12-fold). The state and regulation of human peripheral blood lymphocyte beta 2-adrenoreceptors depend on the hormonal status of patients at the moment of blood sample collection.

Beta-blocker action on lymphocyte proliferative response in essential hypertension.

The proliferative response of phytohaemagglutinin (PHA) - stimulated lymphocytes of healthy donors and hypertensive subjects was analysed according to 3H-thymidine incorporation and cell cycle phase position on a flow cytofluorimeter. 3H-thymidine uptake and the percentage of cells in (S + G2) phase were significantly lower in hypertensive patients. After short-term propranolol administration the lymphocyte blastogenic response in essential hypertension increased by 30--100%. The data suggest that the change in mitogenic response of lymphocytes in essential hypertension results from changes in the distribution of lymphocyte subclasses. The connection between the sympathoadrenal and immune system is discussed.

[Effect of a beta 2-blocker on the adrenergic receptors of lymphocytes in hypertension]. / Deistvie beta 2-blokatora na adrenergicheskie retseptory limfotsitov pri gipertonicheskoi bolezni.

A short-term effect of propranolol on beta 2-adrenoceptor density in mononuclear lymphocytes was studied in 15 male patients with essential hypertension. According to receptor density alterations the hypertensive subjects were divided into two groups. In the first group lymphocyte beta 2-receptor density increased substantially (3 times, on the average). Propranolol had a weak antihypertensive effect in this group, with the initially low plasma renin activity remaining unchanged after the treatment. The patients of the second group, on the contrary, revealed features of sympathetic hyperactivity and a decrease (2 times on the average) in lymphocyte beta 2-receptor density. Propranolol administration caused a decline in the initially normal or elevated plasma renin activity as well as in systolic arterial blood pressure and heart rate.

[Changes in the density of human lymphocyte beta-adrenergic receptors in hypertension]. / Izmenenie plotnosti beta-adrenergicheskikh retseptorov limfotsitov cheloveka pri gipertonicheskoi bolezni.

The beta-adrenoreceptor density in intact lymphocytes of peripheral blood of normotensive and hypertensive adults was measured by the radioligand binding technique with the use of 3H-dihydroalprenolol. The density of beta-adrenoreceptors was found to be higher in lymphocytes of hypertensive subjects while the number of the receptors was equal to 2076 +/- 208 and 1461 +/- 175 receptors per cell, respectively, in hypertensive and normotensive subjects. The dissociation constants in both cases varied from 0.4 to 1.8 nM. Probably, the decreased responses to the adrenergic agents in hypertensive subjects are not connected with the decreased number of beta-adrenoreceptors and may be due to alterations in postreceptor events.