DNA conformation and thermostability in urea aqueous solutions

It is suggested from the character of the change of circular dichroism spectra that in the presence of urea winding of DNA double helix takes place within the bounds of B-family of forms. It is shown that the realized conformation of DNA differs from the experimentally known forms of DNA belonging to B-family. Urea destabilizes the DNA molecules without connection with helical and melt pairs of DNA nitrous bases. Urea affects the conformational state of DNA by water destruction around DNA, which is accompanied by dehydration of DNA and basic metal ions.     

Structural characteristics of DNA from sarcoma 45

It is shown that thermodynamical parameters of thermal melting and the content of 5-methylcytosine for tumor DNA of sarcoma 45 differ from DNA in the norm. The reason of such difference is the presence of regions with changed DNA structure in sarcoma 45, which occurs apparently owing to hypermethylation of cytosine in tumor DNA.     

Effect of blood serum from schizophrenic patients and from normal donors on DNA synthesis in lymphocytes]

The number of DNA-synthesizing lymphocytes in the phytohemagglutinin (PHA)-stimulated cultures of the peripheral blood of schizophrenic patients was determined. Under the mentioned conditions the number of DNA-synthesizing lymphocytes of the schizophrenic patients was 18% less than in the cultures of healthy donors. When the PHA-treated lymphocytes of normal donors were incubated with the serum of schizophrenic patients the number of lymphocytes capable of synthesizing DNA in the presence of PHA fell by 21%.     

Quantitative determination of lysozyme in the blood serum]

A method, based on the lysozyme ability to selective sorption on chitin followed by reversible enzyme-substrate complex formation, is suggested for quantitative determination of lysozyme in blood serum. The technique offers no difficulty in application, requires no expensive equipment and therefore can be used in clinical practice.