[A study of protein structure changes during hydration by means of diffuse X-ray scattering. II. Fourier transform analysis of X-ray scattering data].

Radial distribution functions were deduced by Fourier transform analysis of angular dependences of diffuse x-ray scattering intensities for the following proteins with different hydration degree: water-soluble a-protein myoglobin, water-soluble alpha+beta protein lysozyme, and transmembrane proteins of photosynthetic reaction centers from purple bacteria Rhodobacter sphaeroides and Blastochlorii viridis. The results of Fourier analysis of x-ray scattering intensities give the quantitative characteristics of the mechanisms underlying the influence of water on the formation of biomacromolecules. Water, on the one hand, weakens the intraglobular hydrogen bond net, loosens the protein structure, and increases the internal conformational dynamics. Concurrently water arranges the stability and ordering of the macromolecule. A sharp correlation is observed between the shift of the "first" peak of radial distribution functions, the weakening of the intraglobular hydrogen bond net, the increase in intraglobular mobility, and the appearance of functional activity in macromolecules. The behavior of the "first" peak is similar to that observed in transmembrane protein of reaction center and water-soluble proteins. The "first" peak for transmembrane protein of reaction center reaches its maximum value much faster (at smaller hydration degrees) than for water-soluble proteins. The fast transfer of reaction center protein to its native state during hydration is due to the fact that the dehydrated conformation of reaction center protein is very close to the native one. From a comparison of the radial distribution functions for water, water-soluble proteins and transmembrane proteins, one may conclude that water has the lowest packing density and the lowest order; water-soluble proteins have a larger packing density and are more ordered than water, and transmembrane proteins have the highest degree of packing density and ordering.

[Organic pathomorphological changes in animals with dietary infection by food products contaminated by Bacillus cereus]. / Patomorfologicheskie izmeneniia organov zhivotnykh pri alimentarnom zarazhenii pishchevymi produktami, obsemenennymi Bacillus cereus.

The authors noticed marked vascular disorders in the capillary system, focal hemorrhages, and inflammatory, largely proliferative reactions in the stroma coupled with dystrophic and necrotic changes in parenchymal elements. The changes were found to be the most pronounced in the intestine, liver, myocardium, and in brain tissue. The degree of the lesions depended on the microorganism dosage. Provided the food contained 10(9)/g Bac. cereus, the injuring action was recorded to be more powerful, which manifested in the increased extent of vascular disorders with the hemorrhagic manifestations, thrombus formation in the vessels of the brain, heart, lungs, stomach and intestine, augmentation of dystrophic changes in organ parenchymal elements.