Characteristics of the meningococcal carrier state in organized collectives and its role in the development of generalized forms of meningococcal infection

Complex (epidemiological and bacteriological) investigations of the level and structure of meningococcal carriership among the members of organized collective bodies differing in the epidemiological situation with respect to meningococcal infection have been carried out. The absence of differences between the total level of meningococcal carriership and the morbidity rate with respect to the generalized forms of meningococcal infection has been shown. The presence of cases of meningococcal meningitis in the groups under study has been found to depend on the intensity of the circulation of certain meningococcal serogroups. The possibility of the ecological reservation of the causative agents of meningococcal infection as polyagglutinable forms has been suggested.     

Factor analysis of rat behavior in the open-field test

Method of major components, a variety of factor analysis, was used for evaluation of rats behaviour motivational structure in the open field test. 40 outbred rats of Wistar line (20 males and females) were examined in which 22 behaviour characteristics were studied. It was shown that a greater part (60%) of rats individual behaviour variability in the open field test was determined by the action of three major components (factors), which were defined as "investigation", "fear" and "shifted activity". Factor structure was studied of main characteristics of behaviour, recorded in the open field test. The use of factor analysis allowed to carry out animals classification on the basis of their disposition in coordinates of the obtained major components.     

A new super-secondary protein structure: the alpha alpha-angle

A novel super-secondary structure consisting of two consecutive alpha-helices connected by a polypeptide chain and packed approximately crosswise is considered in the paper. Such locally ordered regions of proteins are described here as alpha alpha-corners. Almost always one of the two possible "mirror-symmetrical" forms is observed in the proteins. The polypeptide chain of the alpha alpha-corner with a short connection consisting of two peptide units has ...alpha R alpha R alpha L beta beta alpha R alpha R... conformation. It is shown that amino-acid sequences coding for the alpha alpha-corners must have a strictly definite alternation of hydrophobic, hydrophilic and glycine residues. The packing of the remaining alpha-helices of a protein molecule can be obtained if the alpha alpha-corner is taken as the origin of folding.     

Relationship between structure and amino acid sequence of strongly twisted and coiled β-hairpins in globular proteins

β-Hairpins are widespread in proteins, and it is possible to find them both within β-sheets and separately. In this work, a comparative analysis of amino acid sequences of β-strands within strongly twisted β-hairpins from different structural protein subclasses has been conducted. Strongly twisted and coiled β-hairpin generates in the space a right double helix out of β-strands that are connected by a loop region (connections). The frequencies of amino acid residues on the internal (concave) and external (convex) surfaces of strongly twisted β-hairpins have been determined (220 β-hairpins from nonhomologous proteins were studied). The concave surface of these β-hairpins is mainly generated by hydrophobic residues, while the convex surface by hydrophilic residues; accordingly, the alternation of hydrophobic internal and hydrophilic external residues is observed in their amino acid sequences. Amino acid residues of glycine and alanine (especially in places of the largest twisting of the strands) were anomalously frequently found in internal positions of strongly twisted and coiled β-hairpins. It was established that internal positions never contain the proline residues, while external positions in the twisting region contain them in a relatively large amount. It was demonstrated that at least one amino acid residue in α_L- or ε-conformation is required for generation of relatively short (up to 7 amino acid residues) connection. As a rule, these positions are occupied by glycines. Thus, not only the alternation of hydrophobic and hydrophilic amino acid residues, but also the presence of one or two glycine residues in the connection region and the excess of glycines and alanines in the places of the largest strand twisting on the concave surface, as well as the presence of prolines on the convex surface, are required to generate a strongly twisted and coiled β-hairpin.     

Phosphotriester Synthesis of Oligonucleotides with the Use of N- and O-Nucleophilic Intramolecular Catalysis

Abstract

An effective method for the synthesis of oligonucleotides by the phosphotriester approach has been developed. It is based on the use of phosphate protecting groups enabling O-nucleophilic intramolecular catalysis.     

Immobilization of antibiotics on a titanium surface

Immobilization of antibiotics on the surface of electrolytically oxidated titanium was tried. Transfer of the immobilized ampicillin into hardly soluble calcium ampicillate resulted in providing the coating with antimicrobial activity for 5 days. The quantity of the immobilized antibiotic determined polarographically amounted to 6.4.10(-3) mol per 1 m2 of the surface.