Changes in transplantable cultures infected with mycoplasmas isolated from leukemic monkeys]

Four strains of mycoplasms isolated from monkeys with malignant lymphoma and haematosarcoma induced an apparent cytopathogenic effect (CPE) only in the FL culture in the first passage. No visible CPE was observed in L and HeLa, and also in FL cultures of the second and further passages infected with the same mycoplasm strains. However, the infected cultures differed reliably from the control ones by a higher index of cell alteration and by an increased mitotic activity. According to these indices they can be regarded as cultures with a latent CPE.     

Effect of diethylsulphoxide on growth,survival and ion exchange of Escherichia coli

AIMS: To study the effect of diethylsulphoxide (DESO) on Escherichia coli growth, survival and ionic exchange in comparison with dimethylsulphoxide (DMSO). METHODS AND RESULTS: Bacterial survival was estimated by counting colony-forming units and by the most probable number (five-tube) technique; the K+ and H+ transport and H(2) formation were determined electrochemically. Diethylsulphoxide at concentrations between 0.01 and 0.5% (w/v) stimulated and above 5% decreased the anaerobic growth rate and survival. 2H+ : K+ exchange and H(2) formation were lost at 5% DESO. At 0.05% DESO the kinetic characteristics of H+ : K+ exchange and H(2) formation were typical for Delta micro (H(+)) -dependent TrkA uncoupled with F(0)F(1) under respiration. CONCLUSIONS: Diethylsulphoxide at low concentrations serves as an electron acceptor for an anaerobic respiratory chain stimulating bacterial growth and survival through the modulation of H+ : K+ exchange and H(2) formation activity. The effects of DESO were more pronounced than those of DMSO. SIGNIFICANCE AND IMPACT OF THE STUDY: Diethylsulphoxide determines essential biological and therapeutic properties that make its application preferable.     

Membrane potential before and after deep freezing of Escherichia coli in the presence of dimethyl sulfoxide and diethyl sulfoxide

It was shown by the method of penetrating tetraphenylphosphonium cations that low-temperature freezing (-196 degrees C) of Escherichia coli leads to a sharp decrease (from 198 to 85 mV) in membrane potential. Incubation of bacteria in a medium containing dimethyl sulfoxide and diethyl sulfoxide as cryoprotectors results in a reduction of the potential by 16 and 27 mV, respectively. It was also shown that diethyl sulfoxide is more effective in maintaining the membrane potential after freezing--thawing than dimethyl sulfoxide.     

The action of infrasound oscillations on the properties of water and of a DNA solution

The effect of mechanical vibrations (MV) electrical conductivity of water and optical density of aqueous DNA solution. Distilled water was treated with MV of several frequencies from 3 to 5000 Hz with an intensity of 90 dB for 30 minutes. Different sensitivities of water specific electrical conductivity (SEC) were determined (the value of distilled water SEC was 209 +/- 2 microS/m). The greatest decrease of SEC (by 15.7%) under the influence of MV was observed at the frequency of 4 Hz. There was no effect at frequencies higher than 100 Hz. The treatment of DNA water solutions with MV of frequencies 4 and 10 Hz decreased its optical density by 4.2 +/- 1.1 and 4.8 +/- 1.2% correspondingly in comparison with control. In cases of treatment with frequencies of 20 and 50 Hz no effect was observed. The mechanism of MV effect on water can be connected with the changes of system structural characteristics. It is confirmed by experiments with DNA solution, where the decrease of optical density (at 260 nm) under MV treatment is conditioned with the increase of the probability of hydrogen binding formation between the bases.     

Hydrogen bonding versus ion pairing in polyelectrolyte multilayers with homopolynucleotides

Homopolynucleotides--poly(adenylic acid), poly(A), and poly(uridylic acid), poly(U)--were assembled, layer-by-layer, into thin films with poly(ethylenimine), PEI. Various combinations and sequences of polynucleotide and PEI were used to highlight contributions of electrostatic versus hydrogen bonding as driving forces for multilayer build-up. Assembly of alternating poly(A) and poly(U) failed to yield growing films, due to excessively strong interactions between these complimentary strands. The surface morphology of multilayers depended on the deposition order and whether films had been annealed by salt. Films assembled from preformed A/U duplexes (having high persistence lengths) were very smooth. Individual adsorption steps, followed by optical waveguide light-mode spectroscopy, showed that only complementary polynucleotides adsorb by H-bonding to the surface of a growing multilayer. In contrast to behavior usually observed for polyelectrolyte multilayer build-up, the films decreased in thickness with increasing salt concentration.     

A two-year survey on mosquitoes of Lebanon

A total of 6,500 mosquitoes were identified during a two-year survey (1999-2001) in Lebanon, and these belonged to twelve species: Culex pipiens, Cx. laticinctus, Cx. mimeticus, Cx. hortensis, Cx. judaicus, Aedes aegypti, Ae. cretinus, Ochlerotatus caspius, Oc. geniculatus, Oc. pulchritarsis, Culiseta longiareolata and Anopheles claviger. Culex pipiens was the most predominant species in Lebanon, collected indoors and outdoors. It was continuously abundant and active throughout the year. Culex judaicus was a small and rare mosquito and it is reported to occur for the first time in Lebanon. On the coastal areas, Ochlerotatus caspius was very common, and proved to be a complex of species as two forms were detected. One of the vectors of malaria, Anopheles claviger, was collected from May to September, from eight sites in Lebanon. Its breeding sites were restricted to fresh, cool, and clean water in pools and wells. Most of these breeding sites were in the populated Metn County where a few indigenous cases of malaria were reported from 1997-2000. This shows that the reported malaria cases were not imported, but caused by the bites of locally infected Anopheles females.     

Glass-forming property of the system diethyl sulphoxide/water and its cryoprotective action on Escherichia coli survival

In this work the thermal properties of diethyl sulphoxide (Et2SO), as well as its cryoprotective ability are studied and related to other well-known cryoprotectant substances, like dimethyl sulphoxide (Me2SO). We have investigated the thermal properties of Et2SO/water systems using Differential Scanning Calorimetry at a very low heating/cooling rate (2 degrees C/min). Liquid/solid or glassy/crystalline transitions have been observed only for the solutions with content of Et2SO ranging from 5 up to 40% w/w and/or greater than 85%. In the 45-75% w/w Et2SO range we have found a noticeable glass-forming tendency and a great stability of the amorphous state to the reheating. In samples with Et2SO content ranging from 80 to 85%, we observed a great stability of the glass forming by cooling, but a lesser stability to the subsequent reheating. The glass-forming tendency of these solutions is discussed in terms of existing competitive interactions between molecules of Et2SO, on the one hand, and Et2SO and water molecules, on the other hand. The results are well explainable on the basis of the model structure of water/Et2SO solutions, deduced by Raman and infrared studies [J. Mol. Struct. 665 (2003) 285-292]. The cryoprotective ability of Et2SO on Escherichia coli survival has been also investigated, and a comparison among Et2SO and other widely used cryoprotectants, like Me2SO and glycerol has been done. Survival of E. coli, determined after freezing-thawing process, was maximal at 45% w/w Et2SO (more than 85% viability). It should be noted that at the same concentration the survival is only about 35% in the presence of Me2SO and not more than 15% in the presence of glycerol. These features are well consisted with the glass-forming properties of Et2SO.     

Effect of gordox on the pancreas in experimental pancreonecrosis

Early treatment with gordox of white rats with experimental pancreonecrosis reduces amylasemia and prevents dissemination of steatonecroses. The drug appreciably improves pancreatic microcirculation. Similarly to the control, the injured part of the gland undergoes necrosis. However, the severity of hemorrhagic component is minimal. The treatment with gordox enhances leukocytic infiltration aimed at elimination of necrotic tissues.     

Chromosome identification in Macaca arctoides based on study of the differential staining pattern (G-discs). Comparison with Papio hamadryas G-discs]

Linear chromosome differentiation pattern of Macaca arctoides was studied using the Romanovsky-Gimsa stain (G-banding). The possibility of the identification of all chromosome pairs according to these data is demonstrated. The phenomenon of the irregular intercellular and chromosome differentiation is found out and a suggestion is made about its relation to a real mosaic functional activity of cell genomes. A great similarity in linear chromosome differentiation for 2 from 42 studied chromosome types of Macaca arctoides (genus Macaca) and Papio hamadryas (genus Papio) is shown. On the basis of these data it is supposed that in the divergency process of these species the chromosome microaberrations and molecular mutations played an important role, while large chromosome reconstructions were of no importance. The similar G-banding pattern of both metacentric chromosome arms in two species is found and this suggests an isochromosome mechanism of their occurance.