The Role of Cosolvent-Water Interactions in Effects of the Media on Functionality of Enzymes: A Case Study of Luciferase.

A complex heterogeneous intracellular environment seems to affect enzymatic catalysis by changing the mobility of biomolecules, their stability, and their conformational states, as well as by facilitating or hindering continuously occurring interactions. The evaluation and description of the influence of the cytoplasmic matrix components on enzymatic activity are problems that remain unsolved. In this work, we aimed to determine the mechanisms of action of two-component media with cosolvents of various molecular sizes on the complex multi-stage bioluminescent reaction catalyzed by bacterial luciferase.

Structure-Function Relationships in Temperature Effects on Bacterial Luciferases: Nothing Is Perfect.

The evaluation of temperature effects on the structure and function of enzymes is necessary to understand the mechanisms underlying their adaptation to a constantly changing environment. In the current study, we investigated the influence of temperature variation on the activity, structural dynamics, thermal inactivation and denaturation of and luciferases belonging to different subfamilies, as well as the role of sucrose in maintaining the enzymes functioning and stability. We used the stopped-flow technique, differential scanning calorimetry and molecular dynamics to study the activity, inactivation rate, denaturation and structural features of the enzymes under various temperatures.

Design and Analysis of a Mutant form of the Ice-Binding Protein from Choristoneura fumiferana.

Ice-binding proteins are expressed in the cells of some cold adapted organisms, helping them to survive at extremely low temperatures. One of the problems in studying such proteins is the difficulty of their isolation and purification. For example, eight cysteine residues in the cfAF (antifreeze protein from the eastern spruce budworm Choristoneura fumiferana) form intermolecular bridges during the overexpression of this protein.

Mechanisms of Viscous Media Effects on Elementary Steps of Bacterial Bioluminescent Reaction.

Enzymes activity in a cell is determined by many factors, among which viscosity of the microenvironment plays a significant role. Various cosolvents can imitate intracellular conditions in vitro, allowing to reduce a combination of different regulatory effects. The aim of the study was to analyze the media viscosity effects on the rate constants of the separate stages of the bacterial bioluminescent reaction.

Functional divergence between evolutionary-related LuxG and Fre oxidoreductases of luminous bacteria.

In luminous bacteria NAD(P)H:flavin-oxidoreductases LuxG and Fre, there are homologous enzymes that could provide a luciferase with reduced flavin. Although Fre functions as a housekeeping enzyme, LuxG appears to be a source of reduced flavin for bioluminescence as it is transcribed together with luciferase. This study is aimed at providing the basic conception of Fre and LuxG evolution and revealing the peculiarities of the active site structure resulted from a functional variation within the oxidoreductase family.

Inhibition effect of food preservatives on endoproteinases.

The present manuscript proposes a novel approach to assess the impact of food additives on human metabolism by analysing their effect on biomarker enzyme activity. Alterations in the activity of pancreatic enzymes, such as chymotrypsin and trypsin, which are affected by the most common food preservatives, sodium benzoate (E211), potassium sorbate (E202) and sorbic acid (E200), have been evaluated. The proteinase activity was analysed with a bioluminescent method using the light intensity decay constant.

Structural distinctions of fast and slow bacterial luciferases revealed by phylogenetic analysis.

Motivation: Bacterial luciferases are heterodimeric enzymes that catalyze a chemical reaction, so called bioluminescence, which causes light emission in bacteria. Bioluminescence is vastly used as a reporter system in research tools and commercial developments. However, the details of the mechanisms that stabilize and transform the reaction intermediates as well as differences in the enzymatic kinetics amongst different bacterial luciferases remain to be elucidated.

[Antiviral activity and possible mechanisms of action of moraprenil phosphates during experimental infection caused by herpes simplex type 1 virus].

Aim: Study of antiviral activity of moraprenil phosphates (MPP) against herpes simplex type 1 virus (HSV1) in vitro and during experimental infection caused by HSV1 in mice.

Materials And Methods: Activity of MPP in vitro was tested by the ability to suppress formation of symplasts in VERO cells infected with HSV1, strain VR-3. A series of MPP that suppress virus-induced symplast-formation by 30 times was selected for in vivo experiments.

[The preparation phosprenyl suppresses diarrhea and cattle infectious rhinotracheitis virus multiplication in sensitive cell cultures].

Fosprenil suppressed the multiplication of cattle diarrhea virus in calf coronary vessel cell culture. Added to the culture of infected cells in a dose of 200 mg, the drug decreased the virus titer 30-fold in comparison with infected control cultures. Antiviral activity of fosprenil towards infective rhinotracheitis virus multiplication was still higher: in a dose of 100 mg it decreased the virus titer in fetal calf lung culture 100-fold in comparison with the control.

[The effect of Mycoplasma arthritidis superantigen on immunogenesis in transplacental infection].

The immune responsiveness of the progeny of BALB/c mice, responsive to M. arthritidis superantigen (MAS), and C57BL/6 mice, nonresponsive to MAS, infected with M. arthritidis during the second half of pregnancy was studied.

[Protective effect of a new antiviral preparation of phosprenyl in experimental tick-borne encephalitis].

Antiviral activity of phosprenyl was studied in BALB/c mice infected with tick-borne encephalitis (TBE) virus. Up to 60% animals infected with TBE virus survived after 1-3 intramuscular injections of phosprenyl. The mortality in the untreated group infected with the virus was 100%.

Immunological basis for protection in a murine model of tick-borne encephalitis by a recombinant adenovirus carrying the gene encoding the NS1 non-structural protein.

The humoral immune response to flaviviruses is mainly directed to the major envelope protein, E, and a glycosylated non-structural protein, NS1. Cell-mediated immune responses, however, appear to be directed mainly against non-structural proteins. Experiments described here show that a defective recombinant adenovirus (Rad51) containing the gene encoding the NS1 protein of tick-borne encephalitis virus can induce a strong protective immune response against several pathogenic tick-borne flaviviruses in an experimental animal model, and can enhance the efficacy of conventional vaccine preparations.

[A recombinant adenovirus expressing the NS1 nonstructural protein of tick-borne encephalitis virus: some characteristics of the immunologic basis of antiviral action].

Recombinant adenovirus expressing NS1 nonstructural protein of trick-borne encephalitis (TBE) virus (Rad 51) protected mice from many strains of TBE and Omsk hemorhagic fever (OHF) viruses, but virtually did not protect them from Negishi virus. During combined use of whole-virion inactivated TBE vaccine and Rad 51 the recombinant adenovirus notably potentiated the protective effect of the traditional vaccine. The results of adaptive transfer of immunological material from mice infected with Rad 51 showed that both the vaccinated animals' sera and the pool of T and B cells partially protected the recipient mice from lethal TBE infection.

The Possible Immunological Mechanisms of Pathology in Mice with Congenitally Acquired Influenza Infection.

The fact that congenitally acquired viral infection often strongly influences specific and non-specific immunoreactivity is well documented. Viral infection of pregnant female may lead to serious of pathological consequences for the offspring, namely, to mortality, developmental disorders and in less severe cases to body growth retardation, wasting syndrome and immunodeficiency. In this connection, we have studied congenitally acquired influenza infection in CII mice.

[The immunological consequences of congenital infections].

Mice of different strains were inoculated with type A influenza virus or Mycoplasma arthritidis in the second half of pregnancy. A part of the animals born after this inoculation were characterized by a sharp retardation of growth. The study of the immune status of such animals revealed that their proliferative response to mitogenic/superantigenic factors of the infective agents introduced during pregnancy was suppressed or absent, and the cells of their immune system began to recognize syngeneic intact stimulators in the mixed lymphocytes culture as heterogeneous ones.

[The effect of immunomodulating doses of purified staphylococcal anatoxin on the spontaneous and mitogen-induced proliferation of mouse splenocytes].

Purified staphylococcal toxoid (PST) was shown to alter the spontaneous and mitogen-induced proliferation of mouse spleen cells. In vitro, PST inhibited spontaneous proliferation, as well as proliferation induced by the optimal dose of Con A (2 micrograms/ml) and the optimal and suboptimal doses of lipopolysaccharide (LPS) (100 and 50 micrograms/ml). At the same time the dose of 1.

[The immunogenic and protective properties of the cell wall proteins of Listeria monocytogenes].

Two protein antigens with molecular weights of 58 kD (antigen Lm58) and 79/39 kD (antigen Lm79/ 39) were isolated from Listeria monocytogenes cell wall. Only Lm79/39 was shown to protect mice from L. monocytogenes infection, increasing their LD50 and survival time.

[The use of T-activin for the prevention of congenital influenzal infection in mice and the correction of the immune deficiency].

Viremia accompanying influenza infection and the possibility of transplacental passage of the virus into the fetus make it expedient to develop measures for the prophylaxis of intrauterine infection of the fetus in case of influenza during pregnancy. The work presents the optimum scheme of administration of T-activin for prophylactic purposes to pregnant mice with acute influenza infection. Besides, the use of T-activin for immunocorrection in case of established congenital influenza infection in mice is proposed.

[The role of suppressor cells in congenital influenza infection in mice].

Young mice with congenital influenza infection have lower immune responsiveness of lymphocytes to nonspecific mitogens and influenza virus antigens. Lymphocytes of such animals inhibit proliferation of normal lymphoid cells activated with concanavalin A and immune lymphocytes activated with influenza virus antigens. It is assumed that in congenital influenza infection one of the possible mechanisms of immunosuppression in mice is the activation of suppressor T-cells.