[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.

[Characteristics and identification of bacteriocins produced by Lactococcus lactis subsp. lactis 194-K].

The Lactococcus lactis subsp. lactis 194-K strain has been established to be able to produce two bacteriocins, one of which was identified as the known lantibiotic nisin A, and the other 194-D bacteriocin represents a polypeptide with a 2589-Da molecular mass and comprises 20 amino acid residues. Both bacteriocins were produced in varying proportions in all of the studied nutrient media, which support the growth of the producer. Depending on the cultivation medium, the nisin A content was 380- to 1123-fold lower in the 194-K stain culture fluid than that of the 194-D peptide. In comparision to to nisin A Bacteriocin 194-D possessed a wide range of antibacterial activity and suppressed the growth of both Gram-positive and Gram-negative bacteria. An optimal medium for 194-D bacteriocin synthesis was shown to be a fermentation medium which contained yeast extract, casein hydrolysate, and potassium phosphate. The biosynthesis ofbacteriocin 194-D by the 194-K strain in these media occurred parallel to producer growth, and its maximal accumulation in the culture fluid was observed at 14-20 h of the strain's growth.

[The structure of antibiotic eremomycin B].

A new biologically active component, antibiotic eremomycin B, was isolated from the culture liquid of Amycolatopsis orientalis subsp. eremomycini, the producing strain for antibiotic eremomycin. Its structure was established by NMR spectroscopy and mass spectrometry. Eremomycin B was shown to differ from eremomycin by the presence of an N-carboxymethyl substituent in the disaccharide eremosamine fragment.

[Antibiotics produced by Photorhabdus luminescens ZMI, a symbiont of entomopathogenic nematodes].

A novel strain of Photorhabdus luminescens ZMI isolated from nematode larvae Heterorhabditis sp. was shown to produce antibiotic complexes with antibacterial and antifungal activities. The antibiotic complexes secreted extracellularly and intracellularly were separated into individual components. Comparison of their properties with the databases for biologically active compounds suggested that component A was identical to 3,5-dihydroxy-4-isopropylstilbene, components B and H belonged to anthraquinone derivatives, component C secreted only extracellularly was likely a novel antibiotic.

[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.

[A comparison of the properties of bacteriocins formed by Lactococcus lactis subsp. lactis strains of diverse origin].

Bacteriocins formed by four strains of Lactococcus lactis subsp. lactis have been studied and compared: 729 (a natural strain isolated from milk), 1605 (a mutant of strain 729), F-116 (a recombinant obtained by fusing of protoplasts of the two related strain 729 and 1605), and a nisin-forming strain obtained by adaptive selection at Moscow State University. Antimicrobial activity studies revealed differences between the strains in the effects on individual groups of microorganisms; the activities of the strains were also distinct from that of Nisaplin (a commercial preparation of the bacteriocin nisin). Methods for isolation and purification of bacteriocins have been developed, making it possible to obtain individual components of antibiotic complexes as chromatographically pure preparations. Bacteriocins formed by the strains of Lactococcus lactis subsp. lactis have been identified and differences in their biological and physicochemical properties, established. A novel potent broad-spectrum antibiotic substance distinct from nisin has been isolated from the recombinant strain F-116.

New chiral stationary phase with macrocyclic glycopeptide antibiotic eremomycin chemically bonded to silica.

A new chiral stationary phase (CSP) was prepared by attachment of macrocyclic glycopeptide antibiotic eremomycin to the epoxy-activated silica under mild conditions. In contrast to CSP with immobilized vancomycin, which is a close structural analogue of eremomycin, the prepared CSP reveals high enantioselectivity for separation of amino acids enantiomers. It was demonstrated by the example of ristocetin A CSP that method of the immobilization of macrocyclic glycopeptide antibiotics affects remarkably the resulting enantioselectivity.

[Antibiotic properties of the strains of the basidiomycete Lentinus edodes (Berk.) sing].

Antibiotic properties of the extracts from the fermentation broth and mycelium of 15 strains of the edible and medicinal basidiomycete L. edodes were studied and it was shown that the extracts were active against grampositive and gramnegative bacteria, yeasts and mycelial fungi, including dermatophytes and phytopathogens. The strains differed by the set of the organisms susceptible to the action of the extracts. Strains of L. edodes combining marked antibiotic properties and high yields of water soluble polysaccharides were screened. The active compounds were detected by preparative TLC. Two of them were identified with UV- and mass spectrometry as lentinamycin B and erytadenine (lentinacin). Lentinamycin B was found to be the main component responsible for the antibiotic activity of the L. edodes strains.

[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.

Structure of microcin C51, a new antibiotic with a broad spectrum of activity.

The structure of microcin C51, a new antibiotic produced by E. coli, has been determined. This antibiotic was shown to be a 1.18 kDa nucleotide peptide. It consists of a heptapeptide with formylmethionine as the N-terminus and a C-terminal asparagine linked with nebularin-5'-monophosphate through the three-methylene bridge. The OH-group of threonine is substituted. The peptide chain of microcin C51 synthesized on ribosomes is the longest among the known biologically active nucleotide peptides.

167-A, a new antibiotic produced by a mutant of an inactive wild strain of Amycolata autotrophica.

Two related antibiotics, 167-A and 167-B, were isolated from the fermentation broth of a mutant of an inactive wild strain of Amycolata autotrophica. Antibiotic 167-B was found to be cervinomycin A2; antibiotic 167-A is a new representative of the same group and has the structure of 18-O-demethyl cervinomycin A2.

[Development of a new method for preparing biologically active compounds based on the typed strain Streptomyces werraensis]. / Razrabotka novogo metoda polucheniia biologicheski aktivnykh soedinenii na osnove tipovogo shtamma Streptomyces werraensis.

The regulatory function of a DNA fragment responsible for actinomycin resistance in the typed strain Streptomyces werraensis ATCC 1365, which produces a macrotetrolide antibiotic, was studied. Metabolic changes made this strain capable of producing an antibiotic complex, which comprises four biologically active compounds absent from the parent culture.

[An antibiotic complex produced by Streptomyces werraensis 1365T strain]. / Antibioticheskii kompleks, obrazuemyi shtammom Streptomyces werraensis 1365 T.

An antibiotic complex comprising four components (A, B, C, and X) was extracted from a native solution and mycelium of Streptomyces werraensis 1365T. The components were purified by column and thin-layer (TLC) chromatographic procedures to study their physicochemical and biological properties. The results were used to identify the substances isolated. The preliminary data allowed us to identify the components X, A, and B as the previously described compounds undecylprodigiosin, anisomycin, and copiamycin, respectively, whereas component C is a natural compound, which probably has never been described.

[Study of the deglycosylation of various antibiotics of the vancomycin group]. / Issledovanie protsessa deglikozilirovaniia nekotorykh antibiotikov vankomitsinovoi gruppy.

Conditions for deglycosylation of a number of antibiotics belonging to the vancomycin group were studied. A two-stage process including methanolysis followed by acidolysis in a mixture of trifluoracetic acid and HC1 in the presence of nucleophile was shown optimal for formation of a biologically active aglycone of ristomycin A while for formation of the vancomycin aglycone a one-stage process (trifluoracetic acid/HC1--acidolysis) was optimal. A scheme for isolation and purification of the aglycones of ristomycin A and vancomycin is presented.

[A conjugate of ristomycin A ristosaminylaglycon-polymyxin B: the spectrum of its antimicrobial action and its membranolytic activity]. / Kon''iugat ristozaminilaglikon ristomitsina A--polimiksin B: spektr antimikrobnogo deistviia i membranoliticheskaia aktivnost'.

Antimicrobial activity of a conjugate based on two antibiotics, i.e. ristomycin A and polymyxin B was studied. The conjugate was shown to have a broad antimicrobial spectrum. In concentrations of 5 to 30 micrograms/ml it inhibited the growth of gram-positive and gram-negative bacteria and in concentrations of 5 to 40 micrograms/ml it inhibited the growth of the pathogenic clinical strains. An insignificant membranolytic action of the conjugate with respect to membranes of the susceptible bacteria and no hemolytic action on human red blood cells were detected.

[Chemical modification of ristomycin A with bifunctional reagents]. / Khimicheskaia modifikatsiia ristomitsina A bifunktsional'nymi reagentami.

Various bifunctional reagents by the free NH2 group of ristomycinic acid of ristomycin A were used for selective chemical modification of the antibiotic. The bifunctional reagents were the following: di-N-hydroxysuccinimide ether of suberic acid and 4,4'-difluoro-3,3'-dinitrodiphenylsulfone. Bis-N,N'-derivatives of ristomycin A were prepared using these reagents. The derivatives inhibited the growth of Bac. subtilis but the concentrations required for the inhibition were 2-4 times higher than those of ristomycin A. It was noted that the MIC of the bis-N,N'-derivatives depended on the length and flexibility of the "binding foot". The MIC of the bis-N,N'-derivative prepared with using suberic acid was 2 times higher than that of the derivative prepared with the use of 4,4'-difluoro-3,3'-dinitrodiphenylsulfone.

[Composition and structure of the antibiotic polypeptide 308-I from Actinomadura recticatena]. / Sostav i stroenie antibiotika-polipeptida 308-I iz Actinomadura recticatena.

Antibiotic 308-I isolated from Actinomadura recticatena and the products of its degradation were studied with the methods of electron impact mass spectrometry, chemical ionization with ammonia, field desorption and ion extraction from solution under atmospheric pressure. It was shown that by its composition and structure antibiotic 308-I was identical to antibiotic BBM-928 A.

[Isolation and evaluation of the structure of the new anthracycline antibiotics rubomycins F and H]. / Vydelenie i ustanovlenie stroeniia novykh antratsiklinovykh antibiotikov rubomitsinov F i H.

The rubomycin complex produced by Streptomyces coeruleorubidus 4-157 was studied and the two novel anthracyclines i.e. rubomycins F and H were isolated. The study of the physicochemical properties of the novel antibiotics in comparison with rubomycin C (daunomycin) and the specially prepared 3'-N-carbmethoxyrubomycin C showed that rubomycin F was 3'-N-carbethoxydaunomycin and rubomycin H was 3'-N-carbmethoxydaunomycin. Therefore, rubomycins F and H are novel representatives of natural anthracyclines undescribed previously.

[Effect of carbohydrate components of ristomycin A on platelet aggregation in human plasma]. / Vliianie uglevodnogo sostava ristomitsina A na agregatsiiu trombotsitov plazmy krovi cheloveka.

In the process of the investigation, conditions for specific removal of arabinose in tetrasaccharide of ristomycin A, a glycopeptide antibiotic as well as conditions for simultaneous removal of arabinose and mannose-2 bound to actinoidinic acid were determined. The role of arabinose in manifestation of the ristomycin A ability to induce platelet aggregation was shown to be important. Mannose-2 also had the same ability while its level was somewhat lower.

[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.