Antibiotic Activity of Probiotic Strain Bacillus subtilis 534 Against Clinical Isolates of Acinetobacter baumannii.

Probiotic strain Bacillus subtilis 534 is the base of sporobacterin, a pharmaceutical. In submerged culture it showed antibiotic activity against many of gram-positive and gram-negative bacteria and fungi. The spectrum of the antimicrobial activity of the culture fluid depended on the.cultivation time and aeration intensity. It was shown that component No. 1 of the antibiotic complex was effective against clinical isolates of Acinetobacter baumannii: 20 out of 24 isolates were susceptible to component No. 1, including 15 strains out of 16 panresistant isolates.

[Selective Isolation of Rare Actinomycetes from Soil].

Many diverse methods for selective isolation of actinomycetes are used in discovery of organisms producing biologically active substances, as well as in ecological studies. Methods for isolation of rare actinomycetes from soil are reviewed.

[Irumamicin Produced by Streptomyces roseoflavus INA-1278].

The strain Streptomyces roseoflavus INA-1278 is described as a new irumamicin producer. Irumamicin 1278 is different by the antifungal activity from irumamicin produced by the world-known strain Streptomyces subflavus subsp. Irumaensis subps. nov. AM-3603.

[Storage of Actinobacteria of the Genera Streptomyces and Nonomuraea by Low Temperature Preservation].

The influence of storage of actinobacteria Streptomyces hygroscopicus RIA 1433T, Nonomuraea roseoviolacea subsp. carminata INA 4281 and Nonomuraea sp. INA 34-06 at extremely low temperatures (-70 degrees C) for 1.5 years was studied with respect to their viability and antibiotic activity. The spores of the actinobacteria preserved their high viability when freezed at a concentration of 10(5)-10(7) CFU/ml. As for the antibiotic activity against the test culture Micrococcus luteus ATCC 9341, the strains differed: the S. hygroscopicus RIA 1433T colonies preserved their antibiotic activity against the test culture, the antibiotic activity of Nonomuraea roseoviolacea subsp. carminata lowered by 5% and that of N. sp. INA 34-06 lowered by 44%. Differences in the resistance of the strains to the storage at the extremely low temperatures were observed when the suspensions contained low concentrations of the spores (10(2) CFU/ml): S. hygroscopicus RIA 1433T preserved its viability and antibiotic activity during 1.5 years, while N. roseoviolacea subsp. carminata INA 4281 and N. sp. INA 34-06 lost the viability by the 8th month of the storage. The study showed that 10% glycerol solution used as a cryoprotector during the storage had no effect on viability and antibiotic activity of the actinobacteria.

[Biologically active compounds produced by microbial endophytes].

Microbial endophytes present a rich and not fully studied source of novel natural biologically active compounds of wide interest all over the world. The research of natural compounds with various biological effects produced by endophytes are described in the review.

[Dioxidin: antimicrobial activity and prospects of its clinical use at present].

In vitro activity of dioxidin against pathogens of nosocomial infections and its cytotoxicity were estimated. The study involved 300 isolates from patients with nosocomial infections. The MICs of dioxidin were determined with the method of serial dilutions in broth. The dioxidin cytotoxicity was investigated with the MTI assay to assign the cell culture viability. In concentrations of 2 to 1024 meg/mi dioxidin was active against 279/300 (93%) strains. The drug inhibited the growth of all the gramnegative isolates. The highest activitywas observed against Enterobacteriaceae vs. nonfermenting gramnegative bacteria: the median, minimum and maximum MICs of dioxidin were 12 (4-32) and 32 (16-64) mcg/ml respectively. The dioxidin activity against gramnegative bacteria and fungi was lower. The MIC of dioxidin for 7/70 (10%) staphylococcal isolates, 9/28 (32%) enterococcal isolates and all the Candida isolates was > 1024 mcg/ml. The IC50 of dioxidin was 2.4+/-0.3 mM (low cytotoxicity). The results showed that the use of dioxidin as an antimicrobial for local application was advisable in the treatment of gramnegative bacterial infections provided adequate tissue concentrations were attained.

[Isolation and study of antibiotic INA-1132 (chlorothricin), produced by actinomycete strain].

Taxonomic properties of strain INA-1132 producing antibiotic INA-1132 are described. The antibiotic showed activity against grampositive bacteria and fungi. The strain was classified as belonging to the genus Streptomyces and by its taxomic characteristics is most close to S. baarnensis. The experiments with the bacterial culture Halobacterium salinarum (previously H. halobium) revealed hypolipidemic activity of the antibiotic, i. e. its ability to inhibit biosynthesis of sterols. Conditions for the production of the antibiotic, methods of its isolation and purification, as well as the results of the chemical structure elucidation are described. By its physicochemical properties the antibiotic is identical to chlorothricin. The structure of antibiotic INA-1132 was ascertained by X-ray analysis. Conformation of the molecule of chlorothricin (antibiotic 1132) was determined for the first time.

[Echinomycin production by Actinomadura sp. INA 654].

An actinomycete strain designated as Actinomadura sp. INA 654 was isolated from a chernozem soil sample in the Voronezh Region by the soil sample treatment with millimetric waves (EHF band). The strain produced an antibiotic complex of 2 components, named A-654-I and A-654-II. Investigation of their physico-chemical properties showed that A-654-I was identical to echinomycin, a heteropeptide lactone of the quinoxaline group with antitumor activity, while A-654-II proved to be likely a new natural compound. Production of echinomycin by a representative of the Actinomadura genus was detected for the first time. Up to now, only representatives of the Streptomyces genus were known to produce echinomycin.

[Screening of microbial secondary metabolites inhibiting cholesterol biosynthesis with the use of hepatoblastoma G2]. / Otbor mikrobnykh vtorichnykh matabolitov--ingibitorov biosinteza kholesterina s pomozh'iu kul'tury kletok gepatoblastomy G2.

The culture of hepatoblastoma G2 (Hep G2) cells is proposed as an effective model for screening of microbial metabolites--inhibitors of sterol biosynthesis. This model can be applied at early stages of screening procedures and is quite effective for testing of crude extracts of producers' culture broth. The test is based on measurement inhibition of the radiolabelled precursors incorporation in cholesterol and separate fractions of lipids by microbial metabolites in Hep G2 cells. That allows not only to reveal inhibitors of cholesterol biosynthesis, but also to evaluate mechanism of action, including ability to inhibit the synthesis of cholesterol ethers. The cholesterol biosynthesis inhibition was tested at 150 microbial cultures (actinomycetes and imperfect fungi), isolated from soil. The ability to inhibit 14C-acetate incorporation into cholesterol was found in 15-20% of microbial cultures possessing antifungal activity of extracts (culture broth and mycelium).

[The application of succession analysis in combination with extremely high-frequency irradiation to the selective isolation of actinomycetes from soil]. / Primenenie suktsessionnogo analiza v kombinatsii s KVCH-islucheniem dlia selektivnogo vydeleniia aktinomitsetov iz pochvy.

A new method employing succession analysis and extremely high-frequency (EHF) irradiation is proposed for the selective isolation of actinomycetes from soil. Total actinomycetes were efficiently isolated from soil suspensions irradiated in the wavelength band 4.6-5.8 mm on the 14th and 45th days of succession initiated by soil wetting and from soil suspensions irradiated in the wavelength band 8-11.5 mm on the 7th day of succession. The rare actinomycete genera Actinomadura, Micromonospora, Nonomuraea, Microbispora, Amycolatopsis, Pseudonocardia, Saccharothrix, Streptosporangium, Actinosynnema, Nocardioides, and Saccharopolyspora were isolated by either of the two approaches (succession analysis and EHF irradiation); however, the range of isolated rare actinomycetes was considerably wider when the combination of the two approaches was used. For instance, actinomycetes of the rare genera Actinocorallia, Promicromonospora, Actinoplanes, and Kibdelosporangium were isolated only when EHF irradiation was employed at the early stages of succession.

[Isolation of actinomycetes from soil using extremely high frequency radiation]. / Vydelenie aktinomichetov iz pochvy s ispol'zovaniem KVCH-izlucheniia.

A new method employing extremely high frequencies (EHFs) is proposed for the selective isolation of actinomycetes from soil. The pretreatment of soil suspensions with EHF wavelengths of 5.6 and 7.1 mm led to a nonselective isolation of actinomycetes. At the same time, the irradiation of soil suspensions within wavelength bands of 3.8-5.8 and 8-11.5 mm considerably augmented the total number of isolated actinomycetes and increased the fraction of the isolated rare genera by 2 and 7 times, respectively. The rare actinomycete genera were represented by Actinomadura, Microtetraspora, Nonomuraea, Micromonospora, Amycolatopsis, Pseudonocardia, Saccharotrix, and Streptosporangium.

[The hypolipidemic action of antibiotic 86/88 (enniatin B) in a hepatoblastoma G2 cell culture]. / Gipolipidemicheskoe deistvie antibiotika 86/88 (énniatina B) v kul'ture kletok gepatoblastomy G2.

A cyclodepsipeptide antibiotic 86/88 (enniatin B) with strong hypolipidemic action was isolated from the culture liquid of the fungus INA F-86/88 identified as Fusarium lateritium Nees var. stilboides (Wr.) Bilai. In the Hep G2 cell culture the antibiotic suppressed 14C-acetate incorporation into cholesterol (IC50 1.75 microM), cholesterol ethers (IC50 1 microM), triglycerides (IC50 1.3 microM) and free fatty acids (IC50 2.2 microM). The most pronounced effect of the drugs, i.e. the suppression of the cholesterol ethers synthesis is likely due not only to the ACAT inhibition but also to the inhibition of the triglyceride synthesis and the diminishing of the free fatty acids pool in the cells.

[Actinoplanes brasiliensis INA 3802--a producer of peptide antibiotics]. / Actinoplanes brasiliensis INA 3802--produtsent peptidnykh antibiotikov.

In the screening programme for new antibiotics an actinomycete culture designated as 3802 was isolated from a soil sample. The culture produced a complex of peptide antibiotics belonging to the group of lantibiotics. The antibiotic complex included gardimycin (actagardin) and new antibiotics of the same group. By the taxonomic properties strain 3802 was classified as Actinoplanes brasiliensis not previously known to produce gardimycin. Conditions of the antibiotic complex biosynthesis by strain 3802, the isolation methods and biological properties were studied.

[Use of electrical impulses for selective isolation of actinomycetes f rom soil]. / Ispol'zovanie élektricheskikh impul'sov dlia selektivnogo vydeleniia aktinomitsetov iz pochv.

A new method was elaborated for the selective isolation of actinomycetes from soil, which involves the pretreatment of soil samples with electric pulses. The treatment of soil with 3-ms electric pulses at a field intensity of 12 kV/cm2 resulted in a significant (threefold on average) increase in the proportion of representatives of rare actinomycetes isolated. This treatment regime was found to be most efficient for the selective isolation of representatives of the genera Actinoplanes, Micromonospora, Actinomadura, and Microtetraspora. The proportion of representatives of the genera Streptosporangium and Saccharotrix also increased. The treatment of soil samples with 3-ms electric pulses at a field intensity of 16 kV/cm resulted in highly selective isolation of representatives of the genus Nocardioides.

[Induction of antibiotic formation by inactive cultures of actinomycetes. A mutant strain of Streptomyces helvaticus, a new producer of bruneomycin]. / Induktsiia obrazovaniia antibiotikov neaktivnymi kul'turami aktinomitsetov. Mutantnyi shtamm Streptomyces helvaticus-- novyi produtsent bruneomitsina.

After exposure of an inactive actinomycete to ethidium bromide a stable mutant producing an antibiotic on a solid medium was isolated. The exposure to methylnitrosoguanidine provided the isolation of a more productive variant synthesizing the antibiotic in a liquid medium. By UV, IR, NMR and mass spectroscopy the antibiotic was identified as bruneomycin (streptonigrin). The taxonomic investigation of the culture showed that it belongs to Streptomyces helvaticus which is a new culture producing bruneomycin (streptonigrin). Previously it did not synthesize the antibiotic.

Teichuronic acid of the cell wall of Actinoplanes brasiliensis.

The cell wall of Actinoplanes brasiliensis INA 3802 contains a teichuronic acid of unusual structure, as determined in a nondestructive way by 1H- and 13C-NMR spectroscopy. The polysaccharide comprises six tetrasaccharide units of the following composition: -->6)-alpha-D-Glcp-(1-->4)-beta-D-2,3-diacetamido- 2,3-dideoxyGlcpA-(1-->4)-alpha-D-2,3-diacetamido-2,3-dide oxyGlcp-(1-->4)-beta- D-2,3-diacetamido-2,3-dideoxyManpA. A polymer of such structure has not heretofore been reported for procaryotic cell walls.

[An anionic polysaccharide from the cell wall of Actinoplanes brasiliensis INA 3802]. / Anionnyi polisakharid kletochnoi stenki Actinoplanes brasiliensis INA 3802.

The cell wall of Actinoplanes brasiliensis INA 3802 contains a polysaccharide which has an unusual structure. The peculiar structure of the polymer has been established by a nondestructive procedure which included 1H- and 13C-NMR spectroscopy. The polysaccharide consists of six tetrasaccharide links having the following composition -->6(alpha-D-Glc rho-(1-->4)-beta-D-Clc rho 2,3NAcA-(1-->4)-alpha-D-Clc rho 2,3NAc-(1-->4)-beta- D-Man rho 2,3NAcA-(1-->. No structurally identical polymer of the procaryotic cell wall has so far been reported.

[Streptomyces phaeofaciens, strain 51--producer of a novel antibiotic of the aureolic acid group]. / Streptomyces phaeofaciens, shtamm 51--produtsent novogo antibiotika gruppy aureolovoi kisloty.

An actinomycete strain 51 isolated from a soil sample collected in the Gobi Desert (Mongolia) was shown to produce a novel antibiotic of the group of aureolic acid. By the morphological, chemotaxonomic, cultural and physiological properties strain 51 was identified as belonging to Streptomyces phaeofaciens. The strain inhibited the growth of gram-positive bacteria and was inactive against gram-negative microbes and fungi. During natural variation strain 51 segregated into variants of 3 types. The variants differing from those of the main type possessed lower antibiotic activity. It was not observed earlier that S. phaeofaciens strains produced antibiotics of the group of aureolic acid.