Experimental study of the antiviral properties of antibiotic 6734-21]

The effect of antibiotic 6734-21 on the viruses of variolovaccine, Herpes simplex, influenza and classical avian plague was studied on various experimental models. Antibiotic 6734-21 inhibited development of the variolovaccine virus in the tissue culture, in chick embryos, in rabbits with variolovaccine infection, as well as the development of the viruses of Herpes simplex, Aueski, and Newcastle diseases in the tissue culture. It had a virulicidic effect on the viruses of variolovaccine, influenza and classical avian plague.     

Antiviral action of carminomycin and some of its derivatives]

Carminomycin was shown to inhibit the development of both the DNA-containing variolovaccine virus and the RNA-containing grippe virus in chick embryos. Comparison of the effects of rubomycin, carminomycin, 14-oxy-carminomycin and carminomycin complex with bovine serum albumin in experiments with chick embryos showed that the inhibitory effect of carminomycin and its derivatives on the development of the grippe virus was much higher than that of rubomycin. The carminomycin derivatives proved to be much more active in this respect than the initial antibiotic. Carminomycin and its derivatives had a therapeutic effect on mice with experimental grippe pneumonia also on their oral use.     

Virus-inhibiting properties of the carbonyl-conjugated pentaene roseofungin

The antiinfluenza activity of roseofungin, a polyenic macrolide antibiotic was studied in vitro on surviving fragments of the chick embryo chorionallantoic membranes and in ovo on growing chick embryos. It was shown that the antibiotic activity against influenza A and B viruses was sufficiently high. The activity of roseofungin against influenza A virus did not differ from that of remantadin, the most active inhibitor of influenza virus reproduction. However, the activity of roseofungin against influenza B virus was an advantage of this antibiotic over remantadin, which had practically no effect on this virus type. A statistically significant protective effect of roseofungin (p less than 0.05) was shown on the animals with experimental influenza. The study on the antiviral activity of roseofungin against the DNA-containing variolovaccine virus revealed that it markedly inhibited the plague reduction. Roseofungin had a pronounced inhibitory effect on cell neoplastic transformation induced by the RNA-containing oncogenic virus of Rous sarcoma.     

Biological characteristics of culture 6734-21 and the conditions for isolating the antiviral antibiotic it produces

An actinomyceteous strain No. 6734-21 was isolated from a soil sample of Central Asia and classified as Actinomyces bottropensis. It inhibited the development of the phage of the lysogenic culture of Micrococcus lysodeicticus 53-40 (No. 5) and the variolovaccine DNA-containing virus. Actinomyces bottropensis, strain No. 6734-21 produced an antiviral antibiotic classified as one belonging to the actinorodine group.     

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 suppression level directly depended on the enzyme concentration and decreased with an increase in the infection multiplicity. The enzyme had no effect on multiplication of other viruses tested. RNA-ase decreased the infectious properties of the freshly isolated virus-containing material in concentrations showing the antiviral effect. Preliminary incubation of the cells with the enzyme resulted in suppression of the plaque formation by VSV. The RNA synthesis in such cultures treated with RNA-ase was somewhat lower. It was shown that the antiviral effect of RNA=ase was connected with its enzymic activity. RNA-ase has no antiviral effect in the experiments with mice infected with VSV.     

Anti-influenza effect of bacterial RNAse and the pharmacokinetic basis of its administration in experimental studies

Anti-influenzal action of bacterial and pancreatic RNAases was studied. It was shown in ovo that the RNAases had distinct virus inhibiting activity with respect to various strains of the grippe A virus and did not practically differ by their activity from remantadin but unlike it had inhibitory action on the grippe B virus. The anti-influenzal activity of bacterial RNAase in contrast to pancreatic one was detected not only in experiments with developing chick embryos but also in albino mice with lethal influenzal infection. The index of the animal protection by the preparation amounted to 54-90 per cent depending on the virus infecting dose and RNAase administration route, the lifespan of the animals being increased by 2.4 to 3.8 days. It was shown that the anti-influenzal effect of bacterial RNAase correlated with high levels of the exogenic enzyme in blood of the animals after the preparation intravenous administration. Elimination of RNAase was observed already within the first 4 hours after the experiment start. Intranasal administration allowed to increase the residence time of RNAase in blood up to 8 hours at the account of its gradual absorption from the administration site and the preparation availability increased more than 2-fold. The results provided the basis for recommending the intranasal route of bacterial RNAase administration for use in further investigation of RNAase antiviral activity.     

Identification of ribonuclease P activity from chick embryos

RNAase P (EC 3.1.26.5) activity has been identified in chick embryo thigh tissue on the basis of specific cleavage of Escherichia coli 129 nucleotide tRNATyr precursor and has been partially purified by the procedure used for human tissue culture KB cell RNAase P. RNAase P from chick resembles the KB cell RNAase P in substrate specificity, requirement for a divalent cation (Mg2+) and a monovalent cation (K+, Na+ or NH4+) for activity, inhibition by bulk tRNA, ready inactivation by proteases, and increasing instability; with purification. RNAase P activity is also present in whole chick embryos, as well as in liver and heart tissues. Furthermore, crude preparations of RNAase P from chick embryo heart tissue are relatively free of contaminating nucleases.     

Interaction of actinomycetes in relation to an intensification of protease biosynthesis

This work was aimed at studying the interactions during the growth of Actinomyces rimosus producing proteases and Actinomyces violocinereus which did not synthesize secreted proteolytic enzymes. The production of proteases in the association of the actinomycetes was shown to be stimulated by metabolic products released by A. violocinereus into the surrounding medium. The stimulating agent from the cultural broth of this culture accelerated differentiation of the mycelium of the first hyphal generation in A. rimosus, decelerated spore formation of the second hyphal generation, inhibited the growth rate, and increased the rate of protease accumulation as well as the productivity of the synthesis.     

Modification by azocombination of the catalytic properties of ribonucleases

Using pancreatic RNAase and RNAase from Act. rimosus as models, the effect of modification by azocombination on the catalytic properties of enzymes were studied. It was shown that RNAases binding to soluble dextran did not cause any significant changes in their major catalytic properties, when polymeric RNA was used as a substrate. At the same time, the physico-chemical properties of the modified enzymes may result in changes in the catalytic properties in a reaction with low molecular weight substrates. Evidence for this observation can be obtained from the increase in the synthetic activity of modified pancreatic RNAase as compared to the hydrolase activity in the dinucleotide synthesis reaction.     

Characteristics of the ultrastructural organization of Actinomyces rimosus and Actinomyces violocinereus in monocultures and in an association producing extracellular proteases

The ultrastructural organization of Actinomyces rimosus and Actinomyces violocinereus was compared in monocultures and in associations. The cells of the two species can be discriminated by certain cytological characteristics. A rimosus predominated under the studied conditions and periods of growth. This organism had growth processes disordered (intrahyphal growth). A. violocinereus was characterized by the following processes in the association: peptidoglycan hypersynthesis, formation of calloses of the cell wall which occurred in parallel to hypertrophy of mesosomes, a loss of the capability to form capsules, and delayed spore formation. The reduced synthesis of granular and fibrillar material indicated that these products were not associated with exoprotease. The enzymatic activity was higher and could be detected in earlier in the association than in the monoculture of A. rimosus.     

Pharmacokinetic properties of pancreatic and microbial ribonucleases

Pharmacokinetic properties of pancreatic RNAase (RNAase I), RNAase of Bacillus intermedius (RNAase Bi) and RNAase of Streptomyces rimosus (RNAase Sr) were studied on albino rats. RNAase Bi was shown to be characterized by a higher rate and level of absorption into the systemic blood flow, higher retention time, lower elimination from the kidneys and tissues of the peripheral chamber (skeletal muscles) and higher distribution in the other animal organs such as the heart, spleen and brain. It was concluded by the experimental results that the higher antiviral efficacy of RNAase Bi (RNAase Bi greater than RNAase Sr greater than RNAase I), as was known from the literature data, and the ability to stimulate the immunity correlated with higher biological availability of the enzyme in the animals and could be due to its pharmacokinetic properties.     

Effect on drugs changing the intracellular level of adenosine 3',5'-cyclic monophosphate on interferon formation in chick embryo cells of different ages]

The effect of theophylline and adrenaline on the synthesis of interferon induced by the influenza B virus, strain Lee, in a chick embryo tissue culture was studied. Both preparation were found to decrease interferon synthesis when 5-day-old cultures were used; the inhibitory effect was increased when the two drugs were used together. The degree of inhibition of interferon production depended on a dose of the preparation; the inhibition was still present even when the drugs ere introduced several hours after the cells were infected with interferonogen. The treatment of one-day-old cultures with theophylline resulted in increase of interferon synthesis, whereas administration of adrenaline alone or together with theophylline did not affect the level of interferon synthesis. The drugs used produced no effect on the reproduction of the test-virus of vesicular stomatitis, Newcastle disease and Chickungunya viruses in chick embryo cells and influenza B virus in the developing chick embryos. The results obtained are discussed from the point of view of a possible influence of the intracellular adenosine 3',5-cyclic monophosphate level on the synthesis of virus-induced interferon.     

Mutagenic action of N-nitrosodimethylurea on Actinomyces rimosus and Penicillium chrysogenum]

High mutagenic activity of N-nitrozodimethylurea (NDMU), an agent of the group of the nitrozo compounds not studied in detail was shown with respect to prototrophic and auxotrophic strains of Actinomyces rimosus, an organism producing oxytetracycline and Penicillium chrysogenum, an organism producing penicillin. The rate of direct and back mutations in the auxotrophic strain of Act. rimosus under the effect of NDMU was many times higher than that of spontaneous mutations. NDMU was used at one of the selection stages at which a more active variant of Act. rimosus was obtained. This is evident of a possible use of the mutagen for induction of variation with respect to the quantitative feature of oxytetracycline production. A great number of morphologically changed forms and biochemical mutants of Pen. chrysogenum formed under the effect of this substance. NDMU induced a mutant of Pen. chrysogenum capable of selective synthesis of 6-aminopenicillinic acid without addition of the precursor.     

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. It is concluded that biological efficacy of the RNases is determined by their origin and physico-chemical properties.     

Isolation of a bunyamwera group arbovirus from a naturally infected caribou

A Bunyamwera group arbovirus was isolated from the blood and from the brain of a female caribou parasitized with meningeal worms. The virus passed through a 0.45 micron filter; was ether sensitive; possessed no hemagglutination properties; could be propagated in suckling mice, 6-day old chick embryos, and BHK-21 tissue culture; and produced plaques in chick embryo fibroblast tissue culture. Neither complement-fixation or neutralization tests were sensitive enough to determine the serotype of the virus.     

Mutagenic effect of new chemical compounds. IV. Mutagenic effect of dialkylaminoethyl esters of 5,6-dihydro-7H-benz(c)carbazol-carboxylic acids]

The mutagenic effect of dialkylaminoet hyl esters of 5,6-dihydro-7H-benz(c)carbazole-carboxylic acids on biochemical mutants (Escherichia coli P-678, Actinomyces rimosus 222) is found. Hydrochloride of diethylaminoethyl ester of 5,6-dihydro-7H-benz(c)carbazole-9-carboxylic acid, which induced reversible and direct mutations, proved to be the most active compound, its mutagenic activity exceeding considerably the activity of ethylene imine.     

Response of Children to Inactivated Measles Vaccine Prepared in Bovine Renal Cell Culture

Formalin-inactivated, alum-adsorbed measles vaccine was readily prepared from virus grown in calf kidney cell culture infected with the Sugiyama strain of measles virus which had been adapted to this cell culture. The vaccine induced no side reaction of any consequence in vaccinated children, but demonstrated antigenic capacity in children as well as guinea pigs, comparable to that of currently used killed measles vaccines prepared from virus grown in monkey kidney or chick embryo tissue cultures. The host system employed for the preparation of this vaccine has an advantage over monkey kidney or chick embryo tissue cultures which are currently used for manufacture of killed measles vaccine. Bovine kidneys are much easier to obtain and cultivate. Of importance is the fact that calf kidneys are practically free of latent virus, whereas monkey kidneys and chick embryos frequently harbor latent viruses.     

Selection of the optimal conditions for the procurement and regeneration of protoplasts of the industrial strain of Streptomyces rimosus, the producer of oxytetracycline, and the effect of the protoplasting process on the antibiotic activity]

Optimal conditions for protoplasting of the Streptomyces rimosus industrial strain No. 1 producing oxytetracycline were developed. Observation of the early stages of the protoplast regeneration in microchambers showed that there were two regeneration types: normal and anomalous. The latter was likely defined by the glycine effect on cell wall synthesis. It was accompanied by the stage in which the protoplasts had the form of multiplying protoplast-like cells. The protoplasting of the S. rimosus culture producing oxytetracycline resulted in an increase in the variability of an antibiotic producing property and the frequency of low active variants.     

Actinomyces rimosus resistance to oxytetracycline

High frequency of spontaneous and UV-and acridine dye-induced variants susceptible to oxytetracycline (OTC) and deprived of the capacity for synthesizing this antibiotic was observed in strain LST-118 of Actinomyces rimosus. The cells of strain LST-118 of Act. rimosus contained extrachromosomal DNA not found in its OTC susceptible variant BS87, which provides evidence in favour of participation of the extrachromosomal genetic elements in control of OTC resistance of the cells of Act. rimosus, LST-118. The OTC resistance in strain LST-118 is of inducable character. The resistance level is increasing from the beginning of the antibiotic synthesis and initially the subinhibitory concentrations of OTC in the medium were the inductors triggering cellular mechanisms ensuring resistance of the cell to the increasing concentrations of OTC in the medium. The capacity for absorption of OTC in Act rimosus is 2--3 times lower than that in E. coli. The experiments with labeled tetracycline showed that the cells of the actinomycete absorbed OTC when it was present in the medium. The absorption of the main amount of the antibiotic was registered during the first 5 minutes. The difference in absorption of OTC by the cells of the antibiotic resistant and sensitive strains was insignificant.     

N-乙酰半胱氨酸体外对流感病毒H1N1的抑制作用

目的探讨N-乙酰半胱氨酸（N—acetylcysteine,NAC）在体外对流感病毒H1N1的抑制作用。方法采用MTT法、鸡胚接种法和免疫荧光法,观察NAC对流感病毒HlM的抑制作用。采用血球凝集试验、神经氨酸酶活性抑制试验和透射电镜负染技术,初步探讨NAC对流感病毒HlM的抑制机制。结果NAC在MDCK细胞上的最大无毒剂量是6．25mg／mL;流感病毒H1Nl在MDCK细胞上的半数致死感染浓度（TCID-50）为1012-2.25／100μ;在三种作用途径下（治疗性给药、预防性给药和直接灭活后给药）,NAC明显抑制了流感病毒HlNl对MDCK细胞的感染,细胞存活率分别为91．88％、93．21％、94．67％,在对照组,流感病毒H1N1感染后的细胞存活率为28．32％,两者相比差异有统计学意义（P〈0．05）;免疫荧光结果显示,与病毒对照组形成的强特异性荧光相比,三种作用途径感染MDCK细胞后的特异性荧光明显减弱;鸡胚培养法的结果显示,NAC明显抑制了流感病毒H1N1在鸡胚内的增殖,实验组血凝效价低于1：2,对照组血凝效价为1：1024;神经氨酸酶活性抑制试验和透射电镜的结果显示,NAC能够明显抑制流感病毒川N1的神经氨酸酶活性,对流感病毒H1N1的病毒体结构也有明显的破坏作用。结论NAC在体外对流感病毒川N1有明显的抑制作用,其抑制机制可能与NAC对流感病毒血凝素和神经氨酸酶活性抑制及病毒体的直接破坏有关。