[Tyndall's hypochromism in suspensions].

Since the passage of light through each individual particle in a suspension includes the competition of processes of absorption and scattering, it leads to hypochromism--a decrease in the extinction coefficient. Such "scattering" hypochromism increases with the particle size and its refractive index. Since the Tyndall's light scattering in suspensions, where the size of each particle is substantially larger with respect to wavelengths of light, is not strongly dependent on the wavelength, the absorption spectrum (and excitation spectrum) attenuated almost uniformly at different wavelengths. A simple method to find true extinction coefficients from the absorption (or excitation) spectra of diluted suspensions (not having multiple light scattering) is suggested. The experimental data on spectra of hemoglobin in erythrocytes, actinomycin in DNA and flavins in mitochondria are given.

[Protomitohondria of Liver Cells, Their Similarities and Differences between Mitochondria].

In this paper we continue the study of a number of properties of protomitochondria--small young mitochondrial organelles in the animal cells. Protomitochondria were obtained by filtration of total suspension of mitochondria of rat liver through Millipore filters. Protomitochondria contain an active respiratory chain as evidenced by the high rate of oxygen consumption during succinate and NADH oxidation. A shunt succinate:tetrazolium-reductase activity of protomitochondria was lower and NADH-tetrazolium-reductase activity was higher than that in mitochondria. Electrophoresis and gel filtration found no qualitative differences between protomitochondria, 0.25-0.45 µm in diameter, and mitochondria in major protein composition, but some quantitative differences in several bands were found. Perhaps, these differences reflect the process of intracellular maturation of protomitochondria to mitochondria. The data obtained are important for understanding the mitochondriogenesis in the animal cells.

[Mechanism of action of the extracellular bacteriolytic enzymes of Lysobacter sp. on gram-positive bacteria: role of the cell wall anionic polymers of the target bacteria]. / Rol' anionnykh polimerov kletochnykh stenok grampolozhitel'nykh bakterii-mishenei v mekhanizme deistviia na nikh vnekletochnykh bakterioliticheskikh fermentov Lysobacter sp.

The study of the extracellular bacteriolytic enzymes of Lysobacter sp. showed that they can efficiently hydrolyze the peptidoglycan of gram-positive bacteria provided that there is an electrostatic interaction of these enzymes with the cell wall anionic polymers, teichoic and teichuronic acids in particular. The hydrolytic action of bacteriolytic enzymes on the cell wall largely depends on the negative charge of teichoic and teichuronic acids, rather than on their chemical composition.

[The effect of the extracellular bacteriolytic enzymes of Lysobacter sp. on gram-negative bacteria]. / Deistvie vnekletochnykh bakteriologicheskikh fermentov Lysobacter sp. na gramotritsatel'nye bakterii.

The effect of the extracellular bacteriolytic enzymes of Lysobacter sp. on gram-negative bacteria was studied. These enzymes were found to be able to hydrolyze the peptidoglycan that was isolated from the gram-negative bacteria, the hydrolysis being completely inhibited by the cell wall lipopolysaccharide of these bacteria. The native cells of the gram-negative bacteria became susceptible to the bacteriolytic enzymes after the permeability of the outer membrane of the cells had been altered by treating them with polymyxin B.

Specificity of the action of lysoamidase on Staphylococcus aureus 209P cell walls.

Specificity of Staphylococcus aureus 209P cell wall hydrolysis by the L1 and L2-bacteriolytic enzymes from lysoamidase lytic complex was studied. L1-peptidase was shown to display both glycyl-glycine endopeptidase and N-acetylmuramyl-L-alanine amidase enzymatic activities on the S. aureus peptidoglycan molecule, whereas L2-peptidase acts as N-acetylmuramyl-L-alanine amidase.

[Lytic action of lysoamidase from Xanthomonas sp. correlates with the presence of the target ribitol teichoic acids in the cell wall of gram-positive bacteria]. / Liticheskoe deistvie lizoamidazy iz Xanthomonas sp. korreliruet s prisutstviem v kletochnoi stenke grampolozhitel'nykh bakterii--mishenei ribitteikhoevykh kislot.

Lysoamidase, a bacteriolytic complex from the culture liquid of Xanthomonas sp., hydrolyzed the cells walls of Staphylococcus aureus, Streptomyces chrysomallus, and Streptomyces azureus, which contain ribitol teichoic acids in addition to peptidoglycan. The cell walls of Streptomyces roseoflavus, Glycomyces harhinensis, and Nocardiopsis dassonvillei, containing glycerol teichoic acids, were not hydrolyzed by lysoamidase. The extent of the hydrolysis of 20-h Str. chrysomallus cells and cell walls, containing 40% ribitol teichoic acids, was considerably higher than that of 40-h cells and cell walls, containing 15% teichoic acids. Homogeneous bacteriolytic enzymes of the lysoamidase complex (muramidase and two bacteriolytic peptidases) most efficiently hydrolyzed S. aureus and Str. chrysomallus cell walls, characterized by the highest content of ribitol teichoic acids, and did not hydrolyze purified peptidoglycan.

[Bacteriolytic enzyme preparation lysoamidase. Purification and some properties of bacteriolytic peptidase L1]. / Bakterioliticheskii fermentnyi preparat lizoamidaza. Ochistka i nekotorye svoistva bakteriolithceskoi peptidazy L1.

The bacteriolytic peptidase L1 has been isolated from the enzyme preparation of lysoamidase capable to lyze cell walls of gram-positive bacteria using ion-exchange chromatography and gel filtration. Some physico-chemical properties of the enzyme have been established. The molecular mass of L1 is 21 kDa, the pH optimum for Staphylococcus aureus cell lysis is 7-11. The optimal concentration of the buffer is 50 mM; the temperature optimum is 70 degrees C; the half-inactivation temperature is 55 degrees C.