Stabilization of standard samples of levorin and nystatin with antioxidants]

To prolong the storage period of the reference samples of levorin and nystatin, polyenic macrolide antibiotics, their effect of 23 antioxidants was studied by using rapid inactivation. The antioxidants belonged to compounds of different classes. The inactivation was performed at 20, 37 and 50 degrees C in the presence of 1, 2 or 5 per cent of the antioxidants. An antioxidant of the class of partially hydrated oxyquinolines was shown to have the highest stabilizing action on levorin and nystatin. It may be recommended for stabilizing the levorin and nystatin reference samples.     

Pathogenicity of clinical strains of Pseudomonas aeruginosa]

The study of 208 Ps. aeruginosa clinical strains, introduced intraperitoneally into white mice, revealed the statistically significant prevalence of pathogenic cultures (87.5--100%). The pathogenic strains of Ps. aeruginosa were found to have statistically significant differences in their cultural and biochemical properties depending on the kind of clinical material: the strains isolated from blood formed mucoid colonies, the zones of hemolysis and thermolabile or thermostable alkaline phosphatase, and typing could be made in 100% of the isolated cultures; the strains isolated from material of closed cavities formed mucoid colonies and the zones of hemolysis; the pathogenic strains isolated from material of open cavities showed only a tendency towards greater activity in the formation of extracellular sline and greater capacity for the formation of clarification zones on yolk agar as compared with nonpathogenic cultures.     

Characteristics of nonspecific resistance in children with lung diseases due to opportunistic microflora

Acute destructive pneumonia in children was found to be complicated by acute pleural empyema (APE) on days 3-21 of the disease. The time of the development of this complication depended on the state of the nonspecific resistance of the body: the greater was the degree of deficiency as manifested by cell-mediated and humoral immunity indices, the earlier developed APE. Staphylococci and Pseudomonas aeruginosa infected the pleural cavity of children under the conditions of essentially decreased phagocytic activity, phagocytic index, C'H50 and one of the classes of immunoglobulin. The reaction of the body to staphylococci and P. aeruginosa took its course after the type of primary or secondary immune response, depending on the time of infection.     

Molecular biology in the Soviet Russia (An essay)

Stages of the evolvement and development of the major directions of molecular biology in the 1950–1980’s and its prehistory bracketing the 1920–1940’s are considered against the backgrounds of the history of the Soviet science. Short outlines of the lives and activities of the leading scientists who shaped the directions of and provided for success in studying supramolecular cell structures and molecular mechanisms of processes on a cellular level. This essay, which is far from exhaustive in describing the problems that the Soviet scientists have been dealing with, does not cover the studies of the last decade, nor does it evaluate the contributions of the living molecular biologists.     

Study of the structure of the photosynthetic reaction center of the green thermophilic bacteria Chloroflexus aurantiacus

Analysis of the Chloroflexus aurantiacus reaction centre (RC) using both protein and recombinant DNA techniques resulted in determination of its polypeptide composition and the primary structures of its two subunits. A model of the polypeptide chains' folding in the membrane is suggested based on: i) homology between L- and M-subunits of Chloroflexus aurantiacus RC and their counterparts in purple bacteria; ii) comparison of their hydropathy plots, and iii) data on the tertiary structures of purple bacteria RCs. The role of a number of functionally important amino acid residues in the RC electron transport activity is discussed. Limited proteolysis of the RC under non-denaturing conditions was used to determine the contribution of the N-terminal regions to its thermal stability.     

Monomerization of the fragment D dimer of stabilized fibrin by a secretion from the medicinal leech salivary gland]

The salivary gland secretion of the medicinal leech catalyzes the conversion into monomeric form of the fragment D dimer, the product of limited proteolysis of stabilized fibrin. Analysis of N-terminal sequences revealed identical fragments for the D-dimer gamma-gamma-chains and the D-monomer gamma-chains formed via this reaction and established the presence of only one N-terminal amino acid (Ser). These results provide evidence for the preservation of integrity of the polypeptide chains during monomerization of the D-dimer.