Mitochondrial DNA polymorphism in Tuvinian population of reindeer Rangifer tarandus L

Mitochondrial DNA variation was examined in one of the southern most populations of domestic reindeer, inhabiting Tyva Republic (Tuva). In Tuvinian population sequence polymorphism of the mitochondrial DNA D loop region was demonstrated. In a sample of 29 individuals 7 mitotypes were distinguished, pointing to the preservation of rather high level of genetic diversity in this population.     

Thermal denaturation of Na- and Li-DNA in salt-free solutions

Thermal denaturation of Na- and Li-DNA from chicken erythrocytes was studied by means of scanning microcalorimetry in salt-free solutions at DNA concentrations (C_p) from 4.5 · 10^?2 to 1 · 10^?3 moles of nucleotides/liter (M). Linear dependencies of DNA melting temperature (T_m) vs lgC_p were obtained: ((1)) ((2)) for Na- and Li-DNA, respectively. Microcalorimetry data were compared with the results of spectrophotometric studies at 260 nm of DNA thermal denaturation in Me-DNA + MeCl solutions at C_p ? (6–8) · 10^?5 M and C_s = 0–40 mM (Me is Na or Li, C_s is salt concentration). It was found that Eqs. (1) and (2) are valid in DNA salt-free solutions over the C_p range 6 · 10^?5?4.5 · 10^?2M. Protonation of DNA bases due to the absorption of CO₂ from air in Na-DNA + NaCl solutions affects DNA melting parameters at C_s < 4 mM. Linear dependence of T_m on lga₊ is found in Na-DNA + NaCl at C_s > 0.4 mMin the absence of contact of solutions with CO₂ from air (a₊ is cation activity). A dependence of [dT_m/dlga₊] on Li⁺ activity was observed in Li-DNA + LiCl solutions at C_s < 10 mM: [dT_m/dlga₊] increases from 17°–18° at C_s > 10 mM to 28°–30° at C_s ? 0.2–0.4 mM. Spectrophotometric measurements at 282 nm show that this effect was caused by protonation of bases in fragments of denatured DNA in neutral solutions. The Poisson–Boltzmann (PB) equation was solved for salt-free DNA at the melting point. The linear dependence of T_m vs lgC_p was interpreted in terms of Manning's condensation theory. PB and Manning's theories fit the experimental data if charge density parameter (ξ) of denatured DNA is in the range 1.8–2.1 (assuming for native DNA ξ = 4.2). Specificity of Li ions in interactions with DNA is discussed. © 1994 John Wiley & Sons, Inc.     

DNA sequence-specific ligands: XIII. New Dimeric Hoechst 33258 molecules, inhibitors of HIV-1 integrase in vitro

Dimeric Hoechst 33258 molecules [dimeric bisbenzimidazoles (DBBIs)] that, upon binding, occupy one turn of the B form of DNA in the narrow groove were constructed by computer simulation. Three fluorescent DBBIs were synthesized; they consist of two bisbenzimidazole units tail-to-tail linked to phenolic hydroxy groups via penta- or heptamethylene or tri(ethylene glycol) spacers and have terminal positively charged N.N-dimethylaminopropyl carboxamide groups in the molecule. The absorption spectra of the DBBIs in the presence of different DNA concentrations showed a hypochromic effect and a small shift of the absorption band to longer wavelengths, which indicated the formation of a complex with DNA. The presence of an isobestic point in the spectrum indicates the formation of one type of DBBI-DNA complexes. The interaction of DBBIs with DNA was studied by CD using a cholesteric liquid-crystalline dispersion (CLD) of DNA. The appearance of a positive band in the absorption region of ligand chromophores in the CD spectrum of the DNA CLD indicates the formation of a DBBI-DNA complex in which ligand chromophores are arranged at an angle close to 54 degrees relative to the helix axis of DNA, which suggests the localization of the DBBI in the narrow groove of DNA. All the DBBIs were found to be in vitro inhibitors of HIV-1 DNA integrase in the 3'-processing reaction, and, of the three DBBIs, two dimers inhibit HIV-1 integrase even in submicromolar concentrations.     

Base excision repair of DNA: glycosylases

The review considers the role of base excision repair in maintaining the constancy of genetic information in the cell. The genetic control and biochemical mechanism are described for the first stage of base excision repair, which is catalyzed by specific enzymes, DNA glycosylases.     

Formation of purple membranes during salt bacteria cultivation]

Experiments have been carried out on cultivation of halophile with probe selection in the interval of 1--2 hours to record the spectra of repeated disturbed completed inner reflection. Periodicity in the changes of spectral characteristics of the culture with the interval of 20--24 hours is revealed. A clearly expressed dichroism of the amid II band of the membrane complex is found, the absence of this dichroism in the protein isolated from the membrane complex is stated. It is suggested that dichroism revealed is a specific feature of the presence of purpuric membranes in the cells. Spontaneous plane orientation of protein macromolecules in purpuric membranes is established. The level of dichroism of amid II band is shown to depend on fermentation conditions of salt bacteria.     

Morphometric characteristics of hepatocyte mitochondria during internal administration of boron-containing water

The changes of hepatic mitochondrial cells were studied in white male rats during internal application of boron-containing waters, having 250 mg/l concentration of boron, but different ionic-salt basis. Mitochondrial hepatocytes and hepatic boron content relationships were established. It was shown that during boron accumulation in liver (15 applications) decreasing of mitochondrial size occurred, independently, of the type of boron-containing waters. During stable boron level and particularly during its excretion from organism (24 applications, 6 days aftereffect), increase of size of mitochondria and their ellipticity, change of configuration, that depend on the type of applied waters was shown.     

Moderate alcohol consumption is associated with better endothelial function: a cross sectional study

Background

Natural heterologous valved conduits with a diameter greater than 22 mm that can be used for right ventricular outflow tract reconstruction in adults are not commercially available. The purpose of this study was to measure by ultrasonography the maximum diameter of the distended jugular veins of horses and cattle, respectively, to identify a population of animals that would be suitable for post-mortem collection of jugular veins at sizes greater than 22 mm.

Methods

The study population included 60 Warmblood horses, 25 Freiberger horses, 20 Brown Swiss cows, and 20 Holstein cows (including 10 Holstein and 10 Red Holstein). The maximum cross-sectional diameter of the distended jugular veins was measured at a location half-way between the mandibular angle and the thoracic inlet. The thoracic circumference (heart girth length) was used as a surrogate of body size. The jugular vein diameters of the different populations were compared by analysis of variance and the association between heart girth length and jugular vein diameter was determined in each of the four study populations by linear regression analysis.

Results

There was considerable individual variation of jugular vein diameters within each of the four study populations. There was no statistically significant relationship between thoracic circumference and jugular vein diameter in any of the populations. The jugular vein diameters of Brown Swiss cows were significantly larger than those of any of the other populations. Warmblood horses had significantly larger jugular vein diameters compared to Freiberger horses.

Conclusion

The results of this study suggest that the production of bovine or equine xenografts with diameters of greater than 22 mm would be feasible. Differences between species and breeds need to be considered. However, prediction of the jugular vein diameter based on breed and heart girth length in an individual animal is inaccurate.