Comparative study of effect of infrared, submillimeter, and millimeter electromagnetic radiation on wing somatic mutations in Drosophila melanogaster induced by gamma-irradiation

It was shown that the number of spontaneous and gamma-radiation-induced somatic mutations in wing cells of fruit flies (third instar larvae) exposed to laser irradiation of submillimeter range (lambda = 81.5 microns) was significantly lower than in control. Laser irradiation did not affect the number of recombinations. Exposure to laser radiation in the infrared range and electromagnetic waves of the millimeter range (lambda = 3.8 mm) enhanced the effect of gamma-irradiation.     

Relationship between oxidoreductase activity and cytochrome b5 and P-450 levels in Pseudomonas bacteria depending upon the structure of C6-substrate]

The influence of the structure of C6 growth substrate on the activity of oxidoreductases and content of cytochromes b5 and P-450 in cells of Pseudomonas aeruginosa and P. fluorescens was studied. Among the hydrocarbons tested (hexane, 1-hexene, cyclohexene), 1-hexene was the most efficient inducer of the synthesis of cytochromes b5 and P-450 in log-phase cells of the pseudomonads. Substitution of the hydrocarbon substrate for a carbohydrate one (glucose) also resulted in a considerable increase in the activity of enzymes of the NADH-dependent electron-transport chain.     

Interactions of non-histone proteins with immobilized components of chromatin

The specific interaction between non-histone proteins (NHP) of rat thymus and the dextran-immobilized components of chromatin has been investigated. DNA's from E. coli and rat thymus, total histone and reconstituted nucleohistone were used as the affinity sorbents. The distribution of protein fractions in the NHP groups dissociated from chromatin with different ionic strengths was studied by binding on the columns and by SDS-PAAG-electrophoresis. It is shown that NHP of chromatin include the protein components with selective affinity to nucleohistone. These results are discussed in connection with the different functions of NHP in chromatin.     

Effect of disulfide bonds on lysozyme dynamics

The effect of destruction of disulfide bonds on the dynamics of proteins was studied by an example of lysozyme by the methods of molecular dynamics. In lysozyme, in the absence of disulfide bonds, the characteristic times of motions of secondary structure devices increased 3-7 times, whereas the amplitudes of fluctuations of secondary structure devices practically did not vary. In the absence of S-S-bonds, the volume of the molecule decreased approximately by 2%, primarily due to a "cleft" between the major and the small domains of lysozyme. Thus, disulfide bonds not only "glue" the secondary structure devices of the protein but also play a role of "rods", maintaining a certain free volume of the molecule necessary for the realization of its functions.