Role of proteins of the macroglobulin family in the mechanisms of infection

Information on the properties of proteins of the macroglobulin family taking part in the host protection from viral, fungal and bacterial pathogens is reviewed. High plasticity and polyfunctional character of these proteins makes it possible to realize different protective functions. They inhibit the lysis of the cell wall by binding the hydrolases of the pathogen thus blocking its penetration into the cell, directly participate in the presentation of antigens to immunocompetent cells, transport antibacterial substances (interferons, lysozyme) to the zone of infection. In addition, macroglobulins take part in the apoptosis regulation in infected cells, utilization of the lysosomal enzymes of annihilated pathogens. The complexes of macroglobulins with some proteins are powerful inductors of antibody production. Further studies of the properties of these proteins will result in a better understanding of the nature of infectious process. The possibility of artificial formation of macroglobulin complexes with pathogen components or with substances possessing protective or anti-inflammatory properties opens prospects for using these proteins in the fields of vaccinology, gene therapy and molecular biology.     

Modulation of immune system cells by lactobacilli

The influence of lactobacilli on the proliferative potential of immune system cells after the intragastral administration of viable microbial cells and their native filtrates to mice CBA is evaluated. The data have been obtained on the modulating influence of lactobacilli on the formation of T- and B-cell immune response--their role in maintaining homeostatsis and specific features of cell mediated immune reactions after the intragastral administration of virulent Shigella dysenteriae for modeling experimental infection in CBA mice. The mechanisms of the immunomodulating action of lactobacilli on local and systemic reactions of the host as well as realization of the protective properties of lactobacilli against the causative agents of acute enteric infections are discussed.     

Immunomodulating effect of protein fractions isolated from bifidobacteria

The screening of the immunomodulating activity (IMA) of different protein fractions isolated from bifidobacteria was carried out and the capacity of these fractions for changing the proliferative activity of immunocompetent cells was evaluated. Soluble proteins were extracted from lyophilized and sonicated bacterial mass of B. bifidum strain 1 in Na2HPO4 (pH 8) in a water bath at 65 degrees C for 30 minutes. After the formation and removal of nucleic acid sediment the resulting supernatant fluid was dialyzed, its adsorption spectra were analyzed and the fluid was fractionated in a specially proposed device for preparative electrophoresis. Protein fractions were tested for IMA on spleen cells of CBA mice in the reaction of lymphocyte blast-transformation by the level of the inclusion 3H thymidine. The analysis of IMA of protein fractions revealed that their high-molecular components produced a pronounced dose-dependent effect on the proliferative activity of spleen cells. The fractions containing low-molecular components were either inactive (fraction 4) or active only in the maximum dose (fraction 5).     

Harmful cyanobacteria and their cyanotoxins in Egyptian fresh waters – state of knowledge and research needs

Cyanobacterial blooms have increased in freshwater ecosystems worldwide in the last century, mostly resulting from eutrophication and climate change. These blooms represent serious threats to environmental and human health because of the production of harmful metabolites, called cyanotoxins. Like many countries, Egypt has been plagued with cyanobacterial blooms in most water sources, including the Nile River, irrigation canals, lakes and fishponds. However, the data about cyanotoxins produced in these blooms are limited. Only two types of cyanotoxins, microcystins and cylindrospermopsin, have been identified and characterised, mainly from Microcystis and Cylindrospermopsis blooms. The data revealed the presence of microcystins in raw and treated drinking waters at concentrations (0.05–3.8 µg l^?1), exceeding the WHO limit (1 µg l^?1) in some drinking water treatment plants. In addition, Nile tilapia Oreochromis niloticus caught from ponds containing heavy cyanobacterial blooms have accumulated considerable amounts of cyanotoxins in their edible tissues. The data presented here could be the catalyst for the establishment of a monitoring and management programme for harmful cyanobacteria and their cyanotoxins in Egyptian fresh waters. This review also elucidates the important research gaps and possible avenues for future research on cyanobacterial blooms and cyanotoxins in Egypt.     

Evolution of the macroglobulin protein family: from bacteria to primates

Proteins of the macroglobulin family are thioether-containing glycoproteins that act as inhibitors of a wide range of hydrolases, transporters and regulators of cytokine, hormone, lipid and oligonucleotide synthesis. As ancient components of innate immunity, these proteins are involved in folding of endogenous proteins as well as recognition and presentation of exogenous antigens. Interaction of macroglobulins with transmembrane receptors triggers cascades of reactions that regulate energy metabolism, cell division and apoptosis, participate in reproduction and cancerogenesis. A broad spectrum of conformational and functional states of molecules, depending on the type of ligands, and an appropriate set of implemented functions allow us to consider these proteins as key regulators of proteostasis. This review addresses the structure and function of macroglobulin proteins during evolution of organisms staying at different phylogenetic levels.     

Evolution of proteins of macroglobulin family

The first representatives of proteins of the macroglobulin family appeared 500–700 million years ago. At present representatives of this family have been revealed in crustaceans, molluscs, fish, amphibians, reptiles, ticks, insects, birds, and mammals, the macroglobulin family in blood of some species being represented simultaneously by several proteins that have different molecular weight and partly duplicate functions of each other. In different species, they are present as monomers, dimers, or tetramers. The distinguishing feature of each protein subunit is the presence of a “trap” with cyclic thioether on the bottom and of a sufficiently large hydrophobic area. All representatives are able to form complexes with different regulatory substances through covalent or hydrophobic bonds, which allows them to perform a wide range of regulatory functions. The ancient origin, evolutionary conservatism, widespread presence, and a diversity of regulatory functions permit proteins of the macroglobulin family to be considered as the main regulatory biomolecules of organism fluid media.     

Low intensity ultrasonic effects on yeast hexokinase

Summary The kinetics of yeast hexokinase activity exposed to 1 MHz ultrasound of therapeutic intensities 0.1–1.5 W/cm² was studied using traditional physico-chemical methods and by the thermoinactivation approach. Analysis of the kinetic curves and the kinetic parameters, obtained by two independent methods, suggested specific perturbation processes provoked by the ultrasonic waves, viz., the mechanical breakdown of the contact site between monomer units and the subsequent sonochemical modification of the active enzyme site. Low intensity ultrasound also caused the destabilization of the molecular structure of hexokinase as revealed by the apparent thermolability of the sonicated enzyme.     

Climatic Causes of Time Displacement of Plant Flowering in the Central Forest Reserve

Biology Bulletin - Abstract—Meteorological series and phenological data were analyzed in the framework of our environmental monitoring in the southern taiga Central Forest Reserve. During the...     

Behavioral impairments in Morris water maze in rats selectively bred for audiogenic seizure susceptibility (Krushinsky-Molodkina strain)

Krushinsky-Molodkina rats (KM strain) with genetically determined seizure susceptibility (clonic and tonic seizures in response to the sound of an electric bell, Krushinsky, 1960) were tested in two versions of Morris water maze and compared with normal albino rats (Sprague-Dawley and Wistar). The tests revealed a learning deficit in KM rats. They showed slow acquisition in both the spatial version of the test and the version with the platform, less efficient strategy of searching for target platform, and high scores of floating and thigmotaxis. However, males of KM rats (not females) did not differ significantly from Wistar strain in the probe trial in the spatial variant of the Morris test. No preference for searching for the platform at the place of its previous localization was observed in KM females. Together with our previous findings of the low scores in Revecz-Krushinsky test and data of other authors (Batuev et al., 1983) concerning a working memory deficit in the radial maze, the results suggest the of complex cognitive deficit combined with possible increased stress reactivity in KM rats.     

Influence of bacteria of Lactobaccilus genera on cytotoxic activity of splenocytes in experimental animals

Influence of lactobacilli on cytotoxic activity of splenocytes from mice of CBA line was studied in vivo and in vitro (after cultivation of splenocytes with chloroform-killed bacteria, homologous lysates obtained by ultrasound, and with native filtrates). Data on increase of splenocytes cytotoxic functions induced by lactobacilli has been obtained. Mechanisms of lactobacilli-mediated activation of cellular factors of antitumor immunity (cytotoxic lymphocytes and natural killers) were discussed. Information on the ability of cell wall components, cytoplasmic fractions, and substances secreted by lactobacilli to stimulate the immune response of a microorganism is presented.