Morphological characteristics of cultured fresh and thawed pericardium cells

The need for selection of the optimal material for the manufacturing of cardio-patches can be resolved by the use of cryostored autologous pericardial tissue. This short communication is a concise fragment of a large-scale research and demonstrates only the efficiency of cell culturing before and after pericardial preservation in the low temperature conditions.     

The nature of virus strains isolated from patients with poliomyelitis in the Byelorussian SSR 1967-1985

Oligonucleotide mapping of the RNA genome was applied for analysis of poliovirus clinical isolates in Byelorussia in 1967-1985. All the maps have been clearly shown to resemble the reference maps of the corresponding vaccine strains. Examination of the oligonucleotide maps of poliovirus isolates provides a measure of distribution of some of the mutations over the viral genome.     

Conformational peculiarities of polynucleotides with a nonrandom base sequence according to the 1H----3H exchange rate in C8H groups of purinic residues

We have determined the 1H----3H exchange rate constants between water and C8H groups of purinic residues of alternating polynucleotides poly(dA-dT).poly(dA-dT), poly(dG-dC).poly(dG-dC) and poly(dA-dC).poly(dG-dT) as well as homopolynucleotides poly(dA).poly(dT) and poly(dG).poly(dC) in aqueous solutions with high-salt concentrations (3 M NaCl and 4-6 M CsF), in water-ethanol (60%) solution and in 0.15 M NaCl at 25 degrees C. The rate constants for adenine (kA) and guanine (kG) of polynucleotides were compared with corresponding constants for E. coli DNA. dGMP nd dAMP at the same conditions. The relation between exchange rates and conformations of polynucleotides permits the study of their conformational peculiarities in solution. Of three alternating polynucleotides examined in 0.15 M NaCl the exchange retardation was observed only for poly(dA-dT).poly(dA-dT) as compared with that in B-DNA, which is in good agreement with the B-alternating "wrinkled" DNA model. The conformations of poly(dG-dC).poly(dG-dC) and poly(dA-dC).poly(dG-dT), according to the exchange data obtained are within the B form. For homopolynucleotides in 0.15 M NaCl, the KA value for poly(dA).poly(dT) is nearly the same as kA for B-DNA, which indicates the similarity of their conformations, whereas the kG value for poly(dG).poly(dC) is 1.7-fold lower in comparison with the kG value in B-DNA. This seems to be connected with the existence of B = A conformation equilibrium for poly(dG).poly(dC) in solution. The increase of NaCl concentration to 3 M results in a B----Z transition in the case of poly(dG-dC).poly(dG-dC) and in the shift of B = A equilibrium towards the A-form in the case of poly(dG).poly(dC) as is evidenced by alterations of their KG values. Poly(dA-dT).poly(dA-dT) in 6 M CsF and poly(dA-dC).poly(dG-dT) in 4.3 M CsF maintain their inherent conformations in 0.15 M NaCl in spite of the fact that they are characterised by the "X-type" CD-spectrum at these conditions. According to the exchange data the conformation of poly(dA).poly(dT) in 6 M CsF corresponds to the "heteronomous" DNA model or some other structure with lower accessibility of C8H groups of adenylic residues.     

Plasma beta-endorphin and stress hormones in stress and adaptation

The experiments on white rats have shown that the induction of 4 hour stress produces an acute increase in beta-endorphin level, as well as characteristic changes in ACTH, cortisol, insulin, thyroxin and triiodothyronine concentrations. Different types of adaptation (training with short stress periods or injection of rhodiola rosea extract) promote a moderate increase in the amount of serum immunoreactive beta-endorphin, preventing its subsequent stress-induced elevation. Adaptation is characterized by a decrease or total prevention of hormonal changes peculiar to stress. The role of opioid neuropeptides in enhancing stress tolerance and the effect of adaptation factors are discussed.     

Serotonin receptors in the brain of animals selected for their domesticated type of behavior

Participation was studied of central serotonin receptors of the first and second types in behaviour change of animals selected by the character of defensive reaction to man. Serotonin receptors were determined by radioligand method by binding of the brain preparations 3H-serotonin and 3H-spiperone. An increase of C2 receptors number was found in the frontal brain cortex of the tame brown rats in comparison with the aggressive ones. Differences were not found in specific C1-receptor binding in the frontal brain cortex of tame and aggressive brown rats, silver foxes and American minks in various relatively early selection stages. It is supposed that disappearance of aggressive reaction to man at domestication is connected with an increase of C2 receptors number.     

Isolation of recombinant vaccine strains of poliovirus from patients with poliomyelitis

Oligonucleotide maps of some poliovirus type 2 strains isolated from polio cases, while being clearly related to that of the Sabin vaccine type 2 strain, exhibited, nevertheless, marked differences from the reference (vaccine) map. Several large oligonucleotides derived from 4 such strains were subjected to enzymatic sequencing. The results strongly suggest that all of them were intertypic recombinants between the Sabin strains. The 5'-parts of the genomes of these strains were derived from the type 2 vaccine whereas the 3'-parts were of type 1 (in 2 strains) or type 3 (in other 2 strains) origin.     

Phylogenetic diversification of immunoglobulin genes and the antibody repertoire

Immunoglobulins are encoded by a large multigene system that undergoes somatic rearrangement and additional genetic change during the development of immunoglobulin-producing cells. Inducible antibody and antibody-like responses are found in all vertebrates. However, immunoglobulin possessing disulfide-bonded heavy and light chains and domain-type organization has been described only in representatives of the jawed vertebrates. High degrees of nucleotide and predicted amino acid sequence identity are evident when the segmental elements that constitute the immunoglobulin gene loci in phylogenetically divergent vertebrates are compared. However, the organization of gene loci and the manner in which the independent elements recombine (and diversify) vary markedly among different taxa. One striking pattern of gene organization is the "cluster type" that appears to be restricted to the chondrichthyes (cartilaginous fishes) and limits segmental rearrangement to closely linked elements. This type of gene organization is associated with both heavy- and light-chain gene loci. In some cases, the clusters are "joined" or "partially joined" in the germ line, in effect predetermining or partially predetermining, respectively, the encoded specificities (the assumption being that these are expressed) of the individual loci. By relating the sequences of transcribed gene products to their respective germ-line genes, it is evident that, in some cases, joined-type genes are expressed. This raises a question about the existence and/or nature of allelic exclusion in these species. The extensive variation in gene organization found throughout the vertebrate species may relate directly to the role of intersegmental (V<==>D<==>J) distances in the commitment of the individual antibody-producing cell to a particular genetic specificity. Thus, the evolution of this locus, perhaps more so than that of others, may reflect the interrelationships between genetic organization and function.      

Action Spectra for Conversions of Phycochrome c from Nostoc muscorum

The reversibly photochromic pigment, phycochrome c, was extracted from the blue-green alga Nostoc muscorum strain A. Action spectra were determined for in vitro conversions of the pigment from the short wavelength to the long wavelength form and vice versa. The action peak for the absorbance decrease at 650 nm is at 630 nm. During this decrease there is only a slight increase of the absorbance in the green region. Green and yellow light (maximum efficiency at 580 nm) completely restores absorbance at 650 nm. The observations are explained by the existence of three spectrally different forms of phycochrome c: P^c₆₃₀ and P^c₆₅₀ which equilibrate in darkness and P^c₅₈₀ which is reversibly photoconvertible to P^c₆₃₀. We have also measured the absorbance changes brought about by saturating irradiations with light of various wavelengths (“photostationary state spectrum”). Extreme photostationary states were obtained with about 650 nm and 500 nm light.     

Effects of Frost Hardening and Dehardening on Photosynthetic Electron Transport and Fluorescence Properties in Isolated Chloroplasts of Pinus silvestris

Photosynthetic electron transport and low-temperature fluorescence emission properties have been analyzed in isolated chloroplasts during the course of frost hardening and dehardening of Pinus silvestris L. Both the partial electron-transport reactions (H₂O DPIP and Asc./DPIP NADP) and the overall electron transport (H₂O — NAPD) showed decreasing capacities during the course of hardening. Upon exposing the plants to ?5°C and high irradiance a block in the electron-transport chain between the two photosystems developed, whereas the partial reactions still showed activities. The decrease in activity of PSl was accompanied by a decrease in P700 content, as determined by light oxidation of P700, which indicates a correlation between the two changes. Hardening also induced changes in the in vivo chlorophyll organization. During the course of hardening the fluorescence emission bands F692 and F726 decreased relative to F680. These changes were more pronounced if the plants were treated in high than in low irradiance. This suggests a greater destruction of the chlorophyll antennae in close association with the two photoreactions than in the so-called light-harvesting chlorophyll a/b antenna. During dehardening basically the reverse of the changes observed during hardening occurred. The recovery of secondary needles was complete, whereas primary needles only partly recovered.     

Control of cell volume in the J774 macrophage by microtubule disassembly and cyclic AMP

We have explored the possibilities that cell volume is regulated by the status of microtubule assembly and cyclic AMP metabolism and may be coordinated with shape change. Treatment of J774.2 mouse macrophages with colchicine caused rapid microtubule disassembly and was associated with a striking increase (from 15-20 to more than 90 percent) in the proportion of cells with a large protuberance at one pole. This provided a simple experimental system in which shape changes occurred in virtually an entire cell population in suspension. Parallel changes in cell volume could then be quantified by isotope dilution techniques. We found that the shape change caused by colchicine was accompanied by a decrease in cell volume of approximately 20 percent. Nocodozole, but not lumicolchicine, caused identical changes in both cell shape and cell volume. The volume loss was not due to cell lysis nor to inhibition of pinocytosis. The mechanism of volume loss was also examined. Colchicine induced a small but reproducible increase in activity of the ouabain-sensitive Na(+), K(+)-dependent ATPase. However, inhibition of this enzyme/transport system by ouabain did not change cell volume nor did it block the colchicines-induced decrease in volume. One the other hand, SITS (4’acetamido, 4-isothiocyano 2,2’ disulfonic acid stilbene), an inhibitor of anion transport, inhibited the effects of colchicines, thus suggesting a role for an anion transport system in cell volume regulation. Because colchicine is known to activate adenylate cyclase in several systems and because cell shape changes are often induced by hormones that elevate cyclic AMP, we also examined the effects of cyclic AMP on cell volume. Agents that act to increase syclic AMP (cholera toxin, which activates adenylate cyclase; IBMX, and inhibitor of phosphodiesterase; and dibutyryl cyclic AMP) all caused a volume decrease comparable to that of colchicine. To define the effective metabolic pathway, we studied two mutants of J774.2, one deficient in adenylate cyclase and the other exhibiting markedly reduced activity of cyclic AMP-dependent protein kinase. Cholera toxin did not produce a volume change in either mutant. Cyclic AMP produced a decrease in the cyclase-deficient line comparable to that in wild type, but did not cause a volume change in the kinase- deficient line. This analysis established separate roles for cyclic AMP and colchicine. The volume decrease induced by cyclic AMP requires the action of a cyclic AMP-dependent protein kinase. Colchicine, on the other hand, induced a comparable volume change in both mutants and wild type, and thus does not require the kinase.