[Verification of a decrease in the rigidity of the phage lambda DNA polymeric chain in low ionic strength aqueous solutions by testing the polymer-polymer interlink interactions].

Changes in the rigidity of the polymetric chain of phage lambda double-strand DNA have been studied by laser correlation spectroscopy. It was shown that, as the ionic strength increases, the effect of the screening of the hydrodynamic interaction of the links of the polymeric chain specific for polymeric coils arises in a DNA solution. It is assumed that the screening occurs when the threshold of the overlapping of DNA coils is achieved. The overlapping of coils is the result of a previously observed significant rise of DNA coil size from abnormally small DNA coils in low ionic strength buffers (about 10(-2) M Na+ or less) to maximum possible large coils in the 5SSC and 5SSC-like buffers. Further analysis of the far interlink interactions in linear lambda phage DNA coils in similar buffers at pH 7 and 4 confirms the earlier proposal about the role of H+ ions in the appearance of abnormally small DNA coils. The abnormal decrease in the DNA coil size in low ionic strength buffers is not a specific feature of lambda phage DNA only.

[Use of laser correlation spectroscopy for recording of changes in the blood serum composition in leukemia in cattle]. / Primenenie lazernoi korreliatsionnoi spektroskopii dlia registratsii izmenenii v sostave syvorotki krovi pri leikoza krupnogo rogatogo skota.

Blood serum of 350 cows with verified leukemia were studied by light scattering technique. Qualitative estimation of the leukemia probability was made using special classification program. This method was shown to have good resolution and to be more quick than traditional diagnostics.

[The effect of cholesterol and dicetylphosphate on the physical parameters of liposomes]. / Vliianie kholesterina i ditsetilfosfata na fizicheskie parametry liposom.

The physical parameters of liposomes from phosphatidylcholine with cholesterol or dicetylphosphate were investigated. The sizes, electrophoretic mobility, surface density charges of these liposomes were estimated. It has been shown that dicetylphosphate, as well as cholesterol increases the thickness of bilayer of the lecithin liposomes and at the same time the area occupied by one lipid molecule has not been changed by dicetylphosphate in contrast to cholesterol.

[Study of the conformational and intradynamic changes of phage lambda DNA molecules by laser correlation spectroscopy]. / Izuchenie konformatsionnykh i vnutridinamicheskikh izmenenii molekuly DNK faga lambda metodom lazernoi korreliatsionnoi spektroskopii.

Conformational changes of lambda phage DNA macromolecules were investigated by dynamic light scattering (DLS) method. It was shown that the persistence length of B-form DNA in some conditions could could decline to approximately 12 nm. When studying the internal motions in the linear form of phage DNA macromolecule, a deviation was observed of the experimental angular dependence of the first cumulant gamma from theoretical predictions for the gamma in Rouse-Zimm model including hydrodynamic interactions. This deviation appeared in the region qRg >> 1, where Rg is gyration radius and q is momentum vector. The first cumulant deviation to higher frequencies is observed only for B-form DNA. Experimental behaviour of the first cumulant gamma for the A-form DNA coincides with the theoretical one in the Rouse-Zimm model.