Antigenic anachronism of influenza viruses A(H2N2) in Leningrad in 1980. II. The laboratory characteristics of influenza A/Leningrad/80 viruses

As indicated by the results of the hemagglutination inhibition (HAI) test, influenza viruses A/Leningrad/80 contain hemagglutinin (HA), similar to that of virus A/Singapore/1/57 (H2N2). Neuraminidase contained in viruses A/Leningrad/80 belongs to serological subtype N2 and is similar to that of virus A/Singapore/1/57 (H2N2). No differences in the polypeptide composition of the virus-induced proteins of viruses A/Leningrad/527/80, A/Leningrad/549/80, A/Leningrad/553/80 and virus A/Singapore/1/57 used as reference have been detected in the study of their electrophoretic mobility in polyacrylamide gel, as well as the mobility of duplexes obtained by the hybridization of the virion and complement RNA of viruses A/Leningrad/553/80 and A/Singapore/1/57. The results of the HAI test with antisera to purified HA indicate that virus A/Leningrad/549/80 contains HA similar to that of viruses A(H2N2) isolated in 1957, but not in 1964. The HAI test with the sera of polecats having the infection permits the differentiation of viruses A/Leningrad/80 from epidemic viruses A(H2N2) isolated in 1957-1965, including reference virus A/Singapore/1/57. In relation to the latter, the isolates of 1980 are older antigenic mutants. The isolates of 1980 are distinguished from virus A(H2N2), isolated in 1975 from the system of persisting influenza infection in a tissue culture, by mutation in NS-gene and the properties of RNA-polymerase. The authenticity of the isolation of viruses A(H2N2) in Leningrad in 1980 has been proved.     

The effect of cadmium on the EEG and the representation of different forms of wakefulness and rest in the frog Rana temporaria in its diurnal cycle]

It has been demonstrated that single injections of cadmium chloride (10 mg/kg, intramuscularly) to frogs result in sustained (up to 34 hours) hyperactivity which in its duration significantly exceeds activating effect produced by the injection procedure. No significant qualitative changes in spectral parameters of the EEG in the forebrain and midbrain were observed after cadmium injections.     

Biochemical and genetic aspects of pathogenesis of schizophrenia

Some molecular-biological and genetic concepts of development of schizophrenia are discussed. The main attention is paid to the ontogenetic aspect of dopaminergic disturbances and to role of risk factors, including stress, responsible for interaction between the nervous, endocrine, and immune systems during development of schizophrenia.     

Crystal structure of exo-inulinase from Aspergillus awamori: the enzyme fold and structural determinants of substrate recognition

Exo-inulinases hydrolyze terminal, non-reducing 2,1-linked and 2,6-linked beta-d-fructofuranose residues in inulin, levan and sucrose releasing beta-d-fructose. We present the X-ray structure at 1.55A resolution of exo-inulinase from Aspergillus awamori, a member of glycoside hydrolase family 32, solved by single isomorphous replacement with the anomalous scattering method using the heavy-atom sites derived from a quick cryo-soaking technique. The tertiary structure of this enzyme folds into two domains: the N-terminal catalytic domain of an unusual five-bladed beta-propeller fold and the C-terminal domain folded into a beta-sandwich-like structure. Its structural architecture is very similar to that of another member of glycoside hydrolase family 32, invertase (beta-fructosidase) from Thermotoga maritima, determined recently by X-ray crystallography The exo-inulinase is a glycoprotein containing five N-linked oligosaccharides. Two crystal forms obtained under similar crystallization conditions differ by the degree of protein glycosylation. The X-ray structure of the enzyme:fructose complex, at a resolution of 1.87A, reveals two catalytically important residues: Asp41 and Glu241, a nucleophile and a catalytic acid/base, respectively. The distance between the side-chains of these residues is consistent with a double displacement mechanism of reaction. Asp189, which is part of the Arg-Asp-Pro motif, provides hydrogen bonds important for substrate recognition.     

Statistical coupling analysis of aspartic proteinases based on crystal structures of the Trichoderma reesei enzyme and its complex with pepstatin A

The crystal structures of an aspartic proteinase from Trichoderma reesei (TrAsP) and of its complex with a competitive inhibitor, pepstatin A, were solved and refined to crystallographic R-factors of 17.9% (R_free = 21.2%) at 1.70 Å resolution and 15.8% (R_free = 19.2%) at 1.85 Å resolution, respectively. The three-dimensional structure of TrAsP is similar to structures of other members of the pepsin-like family of aspartic proteinases. Each molecule is folded in a predominantly β-sheet bilobal structure with the N-terminal and C-terminal domains of about the same size. Structural comparison of the native structure and the TrAsP-pepstatin complex reveals that the enzyme undergoes an induced-fit, rigid-body movement upon inhibitor binding, with the N-terminal and C-terminal lobes tightly enclosing the inhibitor. Upon recognition and binding of pepstatin A, amino acid residues of the enzyme active site form a number of short hydrogen bonds to the inhibitor that may play an important role in the mechanism of catalysis and inhibition. The structures of TrAsP were used as a template for performing statistical coupling analysis of the aspartic protease family. This approach permitted, for the first time, the identification of a network of structurally linked residues putatively mediating conformational changes relevant to the function of this family of enzymes. Statistical coupling analysis reveals coevolved continuous clusters of amino acid residues that extend from the active site into the hydrophobic cores of each of the two domains and include amino acid residues from the flap regions, highlighting the importance of these parts of the protein for its enzymatic activity.     

A study of the mineral composition and the composition of volatiles of marsh cinquefoil

The mineral composition of different vegetative parts of marsh cinquefoil has been studied by inductively coupled plasma atomic emission spectroscopy and ion chromatography. The volatile oil has been obtained from leaves of marsh cinquefoil by hydro and steam distillation, and its composition has been determined by chromatography-mass spectrometry.     

Mineral content in the wild onion species and their nutritive value

The accumulation of 11 microelements (Fe, Zn, Cu, Co, Mn, Ni, Pb, Cd, Sr, Cr, and Se) by 7 wild onion species of the genus Allium was studied. A. flavescens Bess possesses the higher accumulating capability; it accumulates five of eleven microelements (Cr, Ni, Cu, Zn, and Se) with biological accumulation coefficient (BAC) exceeding 1 and also contains high levels of Fe, Co, and Mn. These features enable this species to be the most promising for the nutrition adjustment of human commons with above-mentioned microelements primarily with Cr, which content in 100 g onion leaves achieves 84% of commons. A. fistulosum L., A. odorum L., and broad-leaved A. nutans form specifically accumulate Cu, Zn, and Se. A. montanum Schmidt is characterized by the accumulation of Zn. A. angulosum and A. schoenoprasum are xharacterized by the accumulation of Se. The broad-leaved forms of A. schoenoprasum L., A. nutans L., and A. odorum L. compared with their narrow-leaved forms accumulate more amounts of Zn and Cu.