Methodological procedures for detecting antibiotic producers among cultures of the family Micromonosporaceae]

Data on intensification of the search for active cultures among Micromonospora are presented. It was shown that the frequency of detecting the antibiotic-producing cultures among Micromonospora under conditions of fermentation on the corn-glucose medium inoculated with agar blocks amounted to 35 per cent. The use of nutrient media of different composition for growing submerged inoculum of Micromonospora demonstrated that the rate of its growth reached maximum on the peastarch medium. The use of this medium for growing submerged seed material for fermentation in the corn-glucose medium increased the frequency of detecting active cultures from 35 to 43.1 per cent. The assay of Micromonospora antibiotic activity twice, i.e. in 96 and 240 hours of the fermentation process increased the frequency of detecting active cultures up to 57.1 per cent and revealing greater variety of antibiotics. Fermentation of Micromonospora cultures simultaneously on 6 different nutrient media inoculated with submerged seed mycelium and assay of the activity for 2 times, i. e. in 96 and 240 hours allowed a detection of up to 76.2 per cent of active strains out of the total number of the isolates.     

Directed isolation of Micromonospora generic cultures from moist soils and silts

The data on the study of various soils and substrates for isolation of Micromonospora from them are presented. It was shown that Micromonospora predominated in moist soils and especially in such substrates as silts where their content with respect to the all actinomycetous isolates amounted to 88.9 per cent. In the silts the content of Micromonospora amounted to 66.6--83 per cent, in the sopromely its content was 66 per cent, while in the ordinary non-moist soil its content was from 6 to 11 per cent. Predominance of Micromonospora in silts and moist soils makes its directed search possible.     

Direct screening for producers of antibiotics among the Micromonospora

A test system was developed for screening organisms producing antibiotics of definite chemical groups or mechanisms of action. The system includes efficient selection of cultures belonging to a definite microbiological taxon (genus Micromonospora), investigation of their biological and taxonomic features, the use of specific selective media with high concentrations of definite antibiotics for isolating antibiotic-producing cultures from natural substrates, the use of specific methods for antibiotic chemical isolation at the initial stages of the screening and chromatographic study of the screened compounds. The system provided efficient screening of valuable antibiotics in a short period.     

Biological Ion Exchanger Resins: III. Molecular Interpretation of Cellular Ion Exchange

The cell is presented as a biological ion exchanger resin. The similarities between ion accumulating cells and ion exchanger resins are correlated. The kinetic characteristics of biological ion exchange are shown to be amenable to analysis by a model commonly used for ion exchanger resins. The theories of ion exchange equilibria currently in use with ion exchanger resins are reviewed with their suitability for adaptation to biological ion exchange in mind.     

Isolation of antibiotic-producing Actinomycetes from soil samples exposed to UV light

The use of nonroutine means in isolation of microorganisms from natural substrates extended the possibilities of detecting new cultures which often appear to be producers of previously unknown antibiotics. A new procedure for isolating actinomyces of definite groups was developed. It implies preliminary exposure of soil suspensions to UV light. With the use of the procedure, 2539 strains of actinomycetes belonging to different genera were isolated. There was a marked decrease after the irradiation in isolation of cultures belonging to Streptomyces, a genus most widely distributed in nature and studied in detail while isolation of cultures belonging to other genera, promising as sources of novel antibiotics, increased. Micromonospora, Amycolatopsis and Nocardia proved to be the most stable to the effect of UV light. With the use of the procedure it is possible to increase 2-3-fold isolation of cultures belonging to Micromonospora, a genus known as a producer of many antibiotics including those used clinically.     

Immobilization of glucose isomerase

The immobilization of glucose isomerase (D-xylose ketol isomerase, EC 5.3.1.5) by covalently bonding to various carriers and by adsorption to ion exchange resins was attempted in order to obtain a stable immobilized enzyme which can be used for continuous isomerization of glucose in a column. Of the covalent bonding methods, the colloidal silica-glutaraldehyde method showed the highest binding capacity and gave the most stable immobilized glucose isomerase. The Ludox HS-30 bound glucose isomerase column showed a half-life of 24 days and an enzyme usage of 0.07 units per gram of isomerized sugar (d.s, fructose 45%). Of the resins used, the macromolecular type or porous type strongly basic anion exchange resins showed the highest binding capacity and gave the most stable immobilized glucose isomerase. The Amberlite IRA-904 resine-bound glucose isomerase showed a half-life of 23 days and an enzyme usage of 0.06 units per gram of isomerized sugar (d.s., fructose 45%). Based on the ease of the immobilization process, the possibility of carrier reuse and the extensive use already achieved by ion exchange resins in the sugar industry, IRA-904 resin was selected as the candidate for commercialization.     

Occurrence of gentamicin-producing micromonosporae in Lake Balaton (W. Hungary)

The total number of platable bacteria in the wet mud material characterized by the predominant occurrence of high-magnesian calcite and protodolomite of the Lake Balaton fluctuates between 3.5 X 10(4) and 2.3 X 10(5) g-1. Actinomycetes constitute about 25-30 per cent of this mud-community and not more than half of them belong to the genus Micromonospora. The presence of 10 species of this genus was detected among the isolated and studied strains identified by means of conventional methods and computer aided numerical analysis in which 20 authentic, mostly type strains of Micromonospora spp. were also involved. All of the three species of gentamicin-producing Micromonospora (M. echinospora, M. purpurea and M. sagamiensis) known so far were found in mud samples. These three species form stable but less numerous populations (less than 0.5 per cent of the total platable microflora) in the Balaton's mud, the members of which are capable to produce gentamicins at about 40-50 micrograms ml-1 level at most.     

Effect of the oxidation-reduction potential of the medium on the production of gentamycin

The medium redox potential had an effect on gentamicin production by Micromonospora purpurea v. violacea, strain VNIIA 7R. The Eh influence was shown to be statistically reliable when the results were expressed in relative units against the control. In the laboratory experiments with low volumes of the medium the Eh increase by more than 170 per cent induced inhibition of gentamicin biosynthesis while the Eh increase by 108 to 168 per cent induced stimulation of the activity.     

Drug resistance of opportunistic enterobacteria isolated from various sources]

Resistance of 159 strains of opportunistic enterobacteria to 9 antibacterial drugs was studied. The strains were isolated from man and cattle. It was shown that the overwhelming majority of the isolates (93 per cent) were polyresistant irrespective of the genus. There was a high frequency of the strains resistant to the widely used antibiotics such as chloramphenicol (73 per cent), ampicillin (73.6 per cent) and rifampicin (95.6 per cent) and sulfanilamides (99.3 per cent). Gentamicin and nalidixic acid proved to be the most active against the cultures: 11.9 and 10 per cent of the resistant strains, respectively. The strains of enterobacteria isolated from different sources had a sensitivity to the antibiotics. Multiple antibiotic resistance to at least 5 drugs, variability of the spectra and high resistance were more characteristic of the isolates from the animals. The necessity of a rational use of antibacterial drugs in veterinary is indicated.     

Release characteristics of ion-exchange resins as buffers in low ionic strength nutrient solutions

The use of synthetic ion-exchange resins as buffers of nutrient ions is a potential mechanism for the control of ion concentrations in nutrient solutions. In this study equilibrium constants for two cation exchange resins and three anion exchange resins were determined at 25°C in low ionic strength systems. The measured constants were used to successfully predict the resin combinations required to achieve desired solution equilibrium concentrations. The effectiveness of these resins in buffering solution ion concentrations was evaluated by examining their release characteristics in circulating systems from which aliquots of solution were withdrawn and replaced with deionised water to simulate plant uptake. Buffering of NO₃ and SO₄ concentrations was effective when manual control of one anion was imposed. The cation resins were ineffective in buffering the concentrations of Ca and Mg with a tendency for the resins to retain most of the Ca and Mg in adsorbed form.     

Isolation and regeneration of Micromonospora olivoasterospora protoplasts

The conditions for preparation and regeneration of the protoplasts of M. olivoasterospora were developed. It was found that effective formation of the protoplasts required preliminary cultivation of M. olivoasterospora in the medium containing glycine in a concentration inhibiting its growth at least by 60-80 per cent. The strains studied markedly differed in their sensitivity to glycine and were highly sensitive to it. The efficacy of the protoplast formation depended on the culture age and increased with the use of the lytic enzyme 3 of Cytophaga dissolvens. The possibility and advisability of the use of prolonged lysis of the Micromonospora cell walls were shown. A rich organic medium was used for regeneration of the protoplasts.     

小单孢菌及其在海洋药物开发中的前景

小单孢菌是除链霉菌外,生产抗生素的另一大家族。从分类地位、生态分布、分离方法以及产生物活性物质的状况等方面,介绍了小单孢菌研究的历史和现状。展望了小单孢菌在海洋药物开发中的前景。     

Comparative study of the antibacterial activity of aminoglycoside antibiotics and their combinations with carbenicillin against Pseudomonas aeruginosa

Antibacterial activity of 7 aminoglycoside antibiotics and combinations of tobramycin or gentamicin with carbenicillin was studied with respect to 33 clinical strains of Ps. aeruginosa. Tobramycin, sisomicin, gentamicin and amicacin showed high levels of antibacterial activity. Tobramycin and sisomicin were 3-4 and 2 times more effective than gentamicin. 100 per cent of the Ps. aeruginosa isolates was sensitive to tobramycin and amicacin. The number of the isolates sensitive to sisomicin and gentamicin amounted to 97 and 94 per cent respectively. The respective numbers for streptomycin and kanamycin were 32 and 11 per cent. No monomycin sensitive isolates were detected. Combination of tobramycin or gentamicin with carbenicillin increased the antibacterial activity of the aminoglycoside antibiotics by 2-16 times and that of carbenicillin by 2-32 times. The synergistic effect of gentamicin or tobramycin with carbenicilin was observed with respect to 50 and 58 per cent of the isolates respectively. No antagonistic effect was detected on the combined use of the antibiotics. The majority of the isolates (96 per cent) were sensitive to combinations of carbenicillin in a concentration of 50 micrograms/ml with tobramycin or gentamicin in concentrations of 0.15 or 0.3 micrograms/ml respectively.     

Isolation of gibberellic acid on ion-exchange resins

Folia Microbiologica - The possibility of isolation of gibberellic acid by means of ion exchange resins was ascertained. The strongly basic anion exchange resins, Amberlite IRA-400, Fluka, Zerolit...     

Action of aureolic acid and dactinomycin group antibiotics on human brain tumors in culture]

The cytotoxic effect of antitumour antibiotics, such as dactinomycin, mithramycin, variamycin and olivomycin on the cells of the human brain tumours (multiform glyoblastoma, arachnoidendotelioma and astrocytoma) grown by the method of the primary plasmic culture was studied. Dactinomycin was superior to the antibiotics of the aureolic acid group in the rate and level of the cytotoxic effect on the tumour cells: 76 per cent of the above tumours were sensitive to dactinomycin, 56 per cent to mithramycin and 52 per cent to variamycin and olivomycin. Among the total number of the tumours sensitive to the drugs the number of the highly sensitive tumours amounted to 57.9 per cent for dactinomycin and 30.8--38.5 per cent for the antibiotics of the aureolic acid group. Definite differences in the efficiency of the antibiotics of the aureolic acid group with respect to different types of the brain tumours were observed.     

Direct screening of antibiotics-siderophores of bacterial origin

Antifungal activity of 275 strains belonging to 15 species of Pseudomonas was studied with using media containing no iron or supplemented with 100 micrograms/ml of FeCl3. 33 per cent of the cultures showed lower activity against phytopathogenic fungi in the presence of iron. Addition of this element did not influence the antifungal activity of phenazin and floroglucin derivatives isolated from Pseudomonas cultures. However, its addition markedly lowered the antifungal effect of some crude antibiotics and fluorescent pigments. A scheme for screening siderophore antibiotics with using Pseudomonas cultures is described.     

Use of cephalosporins in pediatric practice with the study of the immunoleukolysis (leukocytolysis) reaction

The aim of the study was to determine the value of preliminary assay of hypersensitivity to cephalosporin antibiotics such as cephazolin, cefuroxime and cefotaxime with the immunoleukolysis test (ILT). 130 children at the age of 2 months to 7 years treated with one of the antibiotics for various inflammatory diseases of the bronchopulmonary system were examined. Hypersensitivity (the ILT indices over 30 per cent) was observed in 9.2 per cent of the children with respect to cephazolin (kefzol), in 3.9 per cent of the children with respect to cefuroxime (ketocef) and in 0.8 per cent of the children with respect to cefotaxime (klaforan). The results of the ILT combined with those of the conjunctival test allowed to increase the number of indications to differential use of the cephalosporins in children with various pathological processes in the bronchopulmonary system.     

Side effects of antibiotics in rheumatic diseases]

Complications due to antibiotic therapy in rheumatic patients subjected to season bicillin prophylaxis in Minsk within 1965--1975 and in patients with extensive collagenoses were studied. Allergic complications mainly ih the form of allergic reactions in the patients treated with bicillin-3 or picillin-5 were observed in 7.8--16.8 per cent of the patients. Within 10 years 52 cases of anaphylactic shock due to the bicillin use were recorded. Side reactions to antibiotics were observed in 16 (17.3 per cent) out of 92 patients with extensive collagenoses. For prophylaxis of the above complications it is recommended to use rational antibiotic therapy in rheumatic patients, strict registration of allergological states in the anamnesis, testing of microbial sensitivity to the antibiotics.     

1株新抑锈病素产生菌FIM03-1149的分离鉴别

在寻找新型抗真菌抗生素的过程中,从海洋放线菌FIM03-1149发酵液中分离到抗真菌抗生素新抑锈病素(Neorustmicin)。菌株FIM03-1149在多数培养基上生长良好,淡黄-橙黄色,无气生菌丝,不产生可溶性色素。形态特征、化学分类特征和生理生化特性等研究表明菌株FIM03-1149属于小单孢菌属。16SrRNA基因序列分析也表明菌株FIM03-1149属于小单孢菌属,但与最接近已知种Micromonospora siamensisTT2-4T处于不同的进化分支,2个菌株在某些生理生化特性上也有不同。基于上述数据,菌株FIM03-1149可能是小单孢菌属的1个新种。     

Grouping of Micromonospora based on their cultural-morphologic features, antibiotic-sensitivity and formation of antibiotics

500 Micromonospora cultures were subdivided into nine groups on the basis of their cultural-morphological properties, the ability to produce antibiotics of certain chemical classes, and the sensitivity to 18 different antibiotics: aurantiaca (I), cinnamomea (II), cinnamomea-vinacea (III), cinnamomea-olivacea (IV), nigra (V), nigra-violacea (VI), lilacinescens (VII), coerulea (VIII) and brunnea (IX). Cultures belonging to groups I, II, III, V and VI are moderately sensitive to most of the antibiotics and often occur in natural substrates. Black Micromonospora cultures (groups V and VI) mostly produce aminoglycoside antibiotics while brown cultures (groups II and III) form macrolide antibiotics. Cultures belonging to groups IV, VII, VIII and IX have a higher sensitivity to most of the antibiotics and are rarely isolated from natural substrates. These cultures have a weak ability to produce antibiotics.