[Comparative characteristics of the metabolism of E. coli cells with various activity of penicillin acylase].

A correlation between the synthesis and secretion of penicillin acylase (PA; EC 3.5.1.

[Study of amino acid utilization by isogenic strains of Escherichia coli in relation to the culture growth and biosynthesis of penicillin amidase].

Dynamics of free amino acid utilization by isogenic strains of Escherichia coli differing in intensity of their growth and levels of penicillin acylase biosynthesis in media containing corn steep liquor or peptone was studied. It was shown that in both the media some amino acids such as serine, threonine, glutaminic and asparaginic acids were actively utilized by the strains mainly during the culture intensive growth while others such as glycine, alanine and tyrosine were actively utilized during the enzyme biosynthesis. Intensively utilized arginine and proline were probably used for the growth and biosynthesis.

[Regulation of the biosynthesis of aminoacylase and pigments by strains of Actinomyces of the genus Streptoverticillium].

For using actinomyceteous extracellular aminoacylase in production of optically active amino acids it is necessary to have the fermentation broth with lowered contents of extracellular pigments whose accumulation dynamics in the process of the strain growth correlates with the dynamics of the enzyme biosynthesis. The results of the studies showed that it was possible to regulate biosynthesis of the aminoacylase and pigments in the direction of increasing the enzyme production and decreasing the pigment formation by using a medium of the respective composition and providing the respective high temperature and sufficient aeration for the strains.

[Differences in the cytotoxicity mechanisms of pancreatic and microbial ribonucleases].

The effect of pancreatic and microbial ribonucleases (RNAses) on incorporation of labeled precursors, i. e. 14C-uridine, 14C-thymidine and 14C-glycine into the biopolymers of transplantable cell cultures, as well as their effect on radioactivity of the acid insoluble fraction of the cells labeled with 14C-orotic acid was studied.

[Enzyme preparations for research on protein hydrolysates and amino acid mixtures not containing peptides].

Some properties and the hydrolysing ability of two novel enzyme preparations, a proteolytic preparation "C" from Acremonium chrysogenum (Cephalosporium acremonium) and a peptidase preparation (the producer from the family Pseudomanadaceae), are described. The preparations can be used for obtaining protein hydrolysates with different ratios of free amino acids and peptides. The protein hydrolysis with the preparation "C" enables one to obtain hydrolysates containing 13-18% of free amino acids.

[Properties of acylase preparations from an actinomycete culture].

A comparative study of some physico-chemical properties of high-purified preparations of extracellular penicillin-V-acylase and aminoacylase, isolated from the actinomycete Streptoverticillium No 62, revealed the difference in pH and temperature optima, in the sensitivity to the ionic composition of buffer solutions, in the enzyme stability during storage. As for the aminoacylase preparation, its thermostability was studied at different pH values, as well as the effect of specific compounds was tested. Similar to other fungal enzymes, the aminoacylase possesses a wide substrate specificity, and by its stereospecificity can be related to L-aminoacylases, while penicillin-V-acylase is a high-specific enzyme, active against phenoxymethylpenicillin.

[Isolation of a highly pure preparation of cephalexin amidase from bacteria of the genus Xanthomonas].

A procedure for highly purified cephalexin amidase of Xanthomonas was developed. It consists of preparation of a cell-free extract of the culture after cell disintegration, precipitation with ammonium sulfate, dissolution, concentration and elimination of ballast proteins, gel filtration on Sephadex G-25, sorption of ballast proteins on DEAE cellulose and chromatography on KM-cellulose. The enzyme yield is 45-55 per cent.

[Isolation and comparative characteristics of acylase preparations from various antinomycete cultures].

The procedure for isolation of acylases from the fermentation broth filtrates of 3 actinomycetous cultures was developed with a yield of 72-97 per cent and 11-19- fold purification of the preparations. Comparative study of substrate specificity of acylase preparations showed that all of them possessed 2 types of the activity, i.e.

[Antiviral activity of modified RNAses].

Antiviral activity of pancreatic RNase and RNase from Act.rimosus modified by various dextran derivatives was studied with respect to aphthosa and Ayzeku disease viruses. Antiviral activity of pancreatic RNase modified by dextran m-aminobenzylhydroxymethyl ether was lower than biological activity of RNase from Act.

[Antitumor action of RNAses modified by covalent binding with dextran m-aminobenzylhydroxymethyl ether].

Antitumor effect of pancreatic RNase and RNase from Actinomyces rimosus, as well as of their derivatives modified by dextran m-aminobenzylhydroxymethyl ether under different conditions was studied and compared. It was found that the efficacy of actinomycetous enzyme and its modified derivatives was superior to that of the analogous preparations of pancreatic RNase. Antitumor effect of the modified enzymes was higher than that of the native ones and depended on the modification conditions.

[Comparative study of the antiviral activity of pancreatic and microbial RNAse].

The efficacy of pancreatic RNase with microbial enzymes (RN-ases) of Act. rimosus and Bacillus intermedius) was studied comparatively in vitro in a transplantable cell culture of the swine embryokidney with respect to the aphthosa virus (AV) and the virus of the Aujeszky disease (VAD). The VAD proved to be most sensitive to RNases.

[Acylase activity of groups of actinomycetes and bacteria].

The acylase activity of 113 actinomycetous strains and 71 bacterial strains was studied. A number of strains producing acylases, hydrolyzing phenoxymethylpenicillin was detected among the actinomycetous cultures and a number of strains producing acylases active against ampicillin and benzylpenicillin was detected among the bacterial cultures. These acylases may be used in production of semisynthetic beta-lactam antibiotics and their semiproducts.

[Effect of body regulatory mechanisms on the catalytic activity of exogenous enzymes].

An increase in the activity of RNAase in the organs and tissues of mice after administration of exogenous RNAases (pancreatic and actinomycetous) was studied. It was found that the increase in the RNAase activity was higher after administration of the actinomycetous enzyme. This was due to the difference in the sensitivity of the exogenous enzymes to the inhibitor of the mouse RNAase.

[Experimental study of the action of the RNAse from Actinomyces rimosus on the variolovaccine virus].

The effect of Actinomyces rimosus RNAase on the variolovaccine virus was studied. The inhibitory effect of the Actinomyces rimosus RNAase on the variolovaccine virus reproduction in the tissue culture cells was shown. In the experiments with the use of chick embryons and rabbits this effect was less pronounced.

[Modification of nucleases by soluble derivatives of polysaccharides].

Preparations of pancreatic RNAase, ribonuclease Act. rimosus and nuclease Ser. marcescens covalently bound to water-soluble derivatives of polysaccharides (m-aminobenzyl-oxymethyl ether of dextran and mannan, 4beta-oxyethylsulphonylanisol, 4beta-oxyethylsulphonylaniline, 3-Cl-2-oxypropyl ethers of dextran and dialdehydedextran) have been obtained.

[Preparation of extracellular ribonuclease form Actinomyces rimosus 994].

By sequential acid treatment, gel filtration and KM-cellulose sorption a 18--20-fold purified preparation of ribonuclease with a yield of 50--60% was obtained from the culture liquid filtrate of Actinomyces rimosus 994. The preparation had a high specific activity of 450,000--600,000 units/mg protein, contained 85--98% protein, insignificant amounts of carbohydrates and hydroxytetracycline, and no quantities of DNase, phosphomonoesterases, phosphodiesterase or proteases. In RNA degradation (preparation of the total yeast RNA of the Sigma Co.

[Acylase activity of mycophilic fungi].

The acylase activity was studied with 65 cultures of mycophilic fungi belonging to 56 species and 33 genera. Among these: 9 species displayed the acylase activity toward ampicillin; 8 species, toward phenoxymethylpenicillin; 6 species, toward benzylpenicillin; and 21 species manifested the complex activity. Many of the active species belonged to the bionecrotrophic group of mycophilic fungi, the number of necrotrophic fungi was less, while that of biotrophs and saprotrophs was even lower.

[Results of a study of the pharmacokinetics of actinomycete RNAase in the bodies of white rats].

The pharmacokinetics of RNA-ase from Act. rimosus was studied on albino rats. The enzyme activity in the biological tests was determined spectrophotometrically by the increase of the acid-soluble products formed as a result of RNA-ase effect on RNA.

[Characteristics of fucidin biosynthesis by a Fusidium coccineum 257 A strain].

The physiological features of Fusidium coccineum, strain 257 A, an organism producing fusidin were studied. It was found that increased concentrations of the carbon sources in the medium stimulated production of fusidin, while an increase in the content of various forms of nitrogen differently affected the level of the antibiotic viosynthesis: high concentrations of the amino acid-peptide form of nitrogen of corn-steep liquor decreased, while the protein form of nitrogen was associated with consumption of the significant part of carbon in the medium for formation of the fungus mycelium. Therefore, the concentration of the easily mobilizing forms of nitrogen may be considered as a regulator of the growth process of F.

[Effect of Actinomyces rimosus ribonuclease on the reproduction of viruses].

Antiviral activity of RNA-ase isolated from the fermentation broth of Actinomyces rimosus was studied. The effect of the enzyme on multiplication of the viruses of vesicular stomatitis, Newcastle and cariolovaccine diseases was investigated. It was found that the enzyme was capable of suppressing reproduction of the vesicular stomatitis virus (VSV) in the culture of chick fibroblast cells.

[The nucleases of oxytetracycline producing actinomycetes].

The activity of exocellular nucleases, especially RNase, differs among cultures producing oxytetracycline, and belonging or similar to Actinomyces rimosus, and cultures which are not related to this species. The activity of RNase therefore may be regarded as an additional taxonomic characteristic within the species Act. rimosus.

[Study of the immunological properties of Actinomyces rimosus ribonuclease].

The immunological properties of ribonucleases from Act. rimosus were studied in comparison with RNA-ase from the cattle pancreas. The activity of anti-RNA-ase immune sera were determined by the method of specific neutralization of the effect of the above exzymes.

[Some characteristics of fucidin biosynthesis].

Some features of fusidin biosynthesis by 2 strains of Fusidium coccineum were studied proceeding from the peculiar properties of the antibiotic molecule structure. It was found that an increase in the levels of the carbon sources in the medium stimulated the biosynthesis of fusidin, while excessive concentrations of nitrogen especially in its inorganic and amino acidpeptide forms stimulated the organism growth and lowered the antibiotic activity levels. The concentration of nitrogen in the medium is considered as one of the possible control mechanisms in the processes of the fungus growth and biosynthesis of fusidin.