Immunological approach to structural-functional mapping of the membrane receptors

In order to study the structural and functional specificity of different fragments of extracellular domains of the membrane receptors, their immunological blockade and analysis of changes in brain function in health and disease were carried out. Effects of the immunization against unstructured fragments of the neurotrophin receptor (p75 NTR) containing binding sites for a nerve growth factor, amyloid-beta, and proneurotrophin were studied. It was shown that immunization of NMRI mice with synthetic peptides with amino-acid residue sequences corresponding to the p75 NTR fragments 86–93 and 146–153 exerted an adverse effect both on the morpho-functional state of the cortical and hippocampal neurons and on the spatial memory of animals. In contrast, the immunization by the p75 NTR synthetic fragment 167–176 was accompanied by an improvement of these characteristics. The results of the structural-functional mapping of the extracellular domain in neuronal membrane receptors in vivo were in line with the published data of the X-ray analysis. The immunological approach developed in this work provides insight into the peculiarities of the receptor functioning in the course of the Alzheimer’s type neurodegeneration process and favors the development of effective immunological ways for selective therapy of the Alzheimer’s disease.     

The structural-functional organization of the auditory cortex in rats]

Using axonal transport of horseradish peroxidase and electrophysiological mapping technique, studies have been made on structural and functional organization of the auditory cortex in rats. After the injection of HRP to peripheral parts of the auditory cortex, mainly initial neurones were found in the dorsal and median parts of the geniculate body. Electrophysiological experiments revealed the localization of neurones with widespread frequency-threshold curves and high thresholds at characteristic frequency. On the basis of the data obtained, it is suggested that similar to other mammals, rats have the areas of secondary fields of the auditory cortex which surround central coniocortex.     

Antiviral activities of hybrids of two major human leukocyte interferons.

Four hybrid human leukocyte interferon (LeIF or IFN-alpha) genes have been constructed by in vitro recombination of LeIF-A (IFN-alpha 2) and LeIF-D (IFN-alpha 1) genes at common restriction endonuclease sites located within their coding regions. These hybrid genes have been expressed in E. coli under trp promoter control. The interferons produced [LeIF-AD (BglII), -AD (PvuII), -DA (BglII), -DA (PvuII)] have antiviral properties distinct from the parental molecules LeIF-A and -D, varying considerably in their abilities to inhibit plaque formation by different viruses in a range of mammalian cells. All six of the cloned LeIFs exhibit the heat stability, pH 2 stability and antigenic specificity of natural leukocyte interferons.     

A new approach to study fibroblast migration

This paper presents a new approach to study cell migration. Human tendon fibroblasts were plated on silicone membranes coated with 10 microg/ml ProNectin-F. The silicone surfaces were micro-fabricated with parallel microgrooves, with 10 microm ridge and groove width, and 3 microm groove depth. Fibroblasts grown in the microgrooves had an elongated shape and oriented along the microgroove direction. They also moved along the same direction instead of "random walk" when cells migrate on smooth culture surfaces. In response to TGF-beta1 (5 ng/ml) treatment, these fibroblasts on the microgrooved surfaces were differentiated into myofibroblasts, as judged by an elevated expression of alpha-smooth muscle actin (alpha-SMA), a specific marker for myofibroblasts. Moreover, these myofibroblasts were found to be approximately 30% less motile compared to that of untreated fibroblasts. Thus, use of microgrooved surface may be an effective approach to detect difference in cell motility because cell migration on the microgrooved surface is one dimensional and hence easier to be quantified than two-dimensional random movement on conventional smooth culture surfaces.     

A Molecular approach to chromosome organization

A 315 kb walk in the genetically well characterized rosy region of the Drosophila chromosomes permits a molecular analysis of chromosome organization. Polytene chromosome bands in this region range from less than 7 kb to about 160 kb and the level of DNA replication is constant within bands and among bands and interbands. A good numerical and topographical correspondence is found between chromomeric units and genetic units.     

Antiviral activity of benzimidazole derivatives. II. Antiviral activity of 2-phenylbenzimidazole derivatives

Seventy-six 2-phenylbenzimidazole derivatives were synthesized and evaluated in cell-based assays for cytotoxicity and antiviral activity against a panel of 10 RNA and DNA viruses. The most commonly affected viruses were, in decreasing order, CVB-2, BVDV, Sb-1, HSV-1, and YFV, while HIV-1 and VSV were not affected, and RSV, VV and Reo-1 were only susceptible to a few compounds. Thirty-nine compounds exhibited high activity (EC₅₀ = 0.1–10 μM) against at least one virus, and four of them were outstanding for their high and selective activity against VV (24, EC₅₀ = 0.1 μM) and BVDV (50, 51, and 53 with EC₅₀ = 1.5, 0.8, and 1.0 μM, respectively). The last compounds inhibited at low micromolar concentrations the NS5B RdRp of BVDV and also of HCV, the latter sharing structural similarity with the former. The considered compounds represent attractive leads for the development of antiviral agents against poxviruses, pestiviruses and even HCV, which are important human and veterinary pathogens.     

A new approach to the study of sequence-dependent properties of polynucleotides

A sequence-dependent properly of any long polynucleotide can be related to the properties of a limited number of other polynucleotides. The properties of the constituent sequence subunits need not be individually known. Only the properties of a set of linearly independent sequence combinations in polymers need be known. The number of independent sequences depends on the number of neighboring bases (or base pairs) contributing to the property and on the number of different bases (or base pairs) allowed. General formulae are derived. If only nearest neighbors contribute to a property, there are 13 linearly independent single-strand sequences with four different bases and there are 8 linearly independent double-strand sequences with two different base pairs. The study of independent sequences in polymers should be especially useful with double-stranded polynucleotides. It should be possible by this polymer approach to estimate nearest-neighbor frequencies from the circular dichroism of double strands and also to investigate the relation between solution conformation and double-strand sequence.     

Peculiarities of structural-functional organization of the motor neuropil in the dragonfly thoracic ganglia

The study considers structural-functional relations in motor neuropil of the thoracic ganglia in dragonflies-insects capable of performing very complex and fast maneuvering in flight. The motor neuropil in dragonflies was shown to be more differentiated than in less mobile insects, while its motor nuclei are more outlined and approached to each other. There were revealed dendrites of the leg muscle motoneurons (intermediate nucleus), running to the anterior and posterior nuclei that contain dendrites of the wing muscle motoneurons. A possible role of such a dendrite approaching is discussed for close functional cooperation of wing and leg muscles essential for dragonflies to catch a large prey in flight by using their legs. Peculiarities of structural organization of the wing muscle motoneurons in dragonflies and locusts are considered to suggest the greater functional capabilities of motoneurons in the dragonfly motor apparatus.     

Antiviral and protein-inducing activities of recombinant human leukocyte interferons and their hybrids.

The antiviral activities of recombinant human leukocyte interferons IFN-alpha A and IFN-alpha D as well as five hybrids of these interferons against retroviruses, vesicular stomatitis virus, and encephalomyocarditis virus were studied in feline, human, and murine cells. Although these interferon species had widely different potencies, their activities against these viruses were, in general, proportional. The IFN-alpha A/D (Bgl) hybrid was the most potent species, and the IFN-alpha D/A (Bgl) hybrid was the least potent. However, the latter species did not interfere with the action of the former species. Like natural human leukocyte interferon, each of the seven species of recombinant interferons induced the synthesis of at least five proteins in human fibroblasts, whereas induction of only one such protein was readily detected in a feline fibroblast line in which these interferon species inhibited the replication of all three viruses.