[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.

[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.

[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.

[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).

[Increase in eremomycin production by regeneration and UV-irradiation of Amycolatopsis orientalis subsp. eremomycini protoplasts]. / Uvelichenie produktsii éremomitsina v rezul'tate regeneratsii i UF-oblucheniia protoplastov Amycolatopsis orientalis subsp. eremomycini.

Protoplast regeneration of Amycolatopsis orientalis subsp. eremomycini producing eremomycin leads to the change of cultural and morphological properties as well as synthesis of secondary metabolites. Formation of plus-variants with enchanced antibiotic production was promoted by UV-irradiation of protoplasts. These plus-variants can be successfully used for repeating protoplasting--UV-irradiation of protoplasts with further increasing of the strain productivity. Finally activity of the initial A. orientalis culture was increased 7-8 times. Proposed method is recommended for the improvement of actinomycetes strains producing antibiotics especially in the case of cultures with poor sporulation.

[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.

[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.

[Isolation and identification of antibiotics produced by Actinoplanes brasiliensis INA 3802]. / Vydelenie i identifikatsiia antibiotikov, produtsiruemykh shtammom Actinoplanes brasiliensis INA 3802.

In the screening programme for new antibiotics produced by Actinoplanes brasiliensis an antibiotic complex A-3802 was isolated and studied in detail. It had a marked therapeutic effect in the treatment of staphylococcal sepsis in albino mice and was low toxic. Two components of the complex i.e. A-3802-IV-3 and A-3802-IV-4 were identified with the lantibiotics actagardin and its diamide disulfoxide. Antibiotics A-3802-V-4 and A-3802-VI-7 were shown to be new antibiotics of the same group.

[Rubomycin Q1--an anthracycline metabolite from Streptomyces coeruleorubidus 2679, a strain producing rubomycin C]. / Rubomitsin Q1--antratsiklinovyi metabolit iz rubomitsin c-produtsiruiushchego shtamma Streptomyces coeruleorubidus 2679.

In the programme of screening of biologically active secondary metabolites produced by Streptomyces coeruleorubidus 2679 a new reddish-violet component (rubomycin Q1) with antibacterial and cytotoxic activity was isolated from the culture fluid of the organism. Some physico-chemical and biological properties of a chromatographically pure rubomycin Q1 were investigated. It was shown with the use of 1H NMR, UV, IR and mass spectrometry that rubomycin Q1 was an anthracycline antibiotic (9,10-anhydro-13-desoxycarminomycin).

[A novel antibiotic of the aureolic acid group. Isolation, physicochemical and biological properties, identification]. / Novyi antibiotik iz gruppy aureolovoi kisloty. Vydelenie, fiziko-khimicheskie i biologicheskie svoistva, identifikatsiia.

An antibiotic complex was extracted from the culture fluid of Streptomyces phaeofaciens, strain 51. By the physicochemical properties it was referred to the group of aureolic acid. The complex was separated to chromatographically pure components by column chromatography. The main component was designated as antibiotic 51-I. Its physicochemical and biological properties were studied. Comparison of the data on the study of antibiotic 51-I with the respective characteristics of the described antibiotics of the group of aureolic acid suggested that antibiotic 51-I is a new representative of this group.

[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.

Eremomycin--new glycopeptide antibiotic: chemical properties and structure.

By a combination of chemical and spectroscopic (1H and 13C NMR) studies the structure of a glycopeptide antibiotic eremomycin has been elucidated. It is closely related to vancomycin, but differs in sugar and chlorine content. The eremomycin aglycone contains monodechlorovancomycinic acid; the only chlorine atom is situated in the second amino acid after the N-terminal amino acid residue of the peptide. The sugar part is composed of glucose and two residues of an amino sugar shown to be 2,3,6-trideoxy-3-amino-C-3-methyl-L-arabino-hexopyranose (4-epi-vancosamine). One of the amino sugar residues is a component of the disaccharide 2-O-(alpha-L-4-epi-vancosaminyl)-beta-D-glucopyranose, attached to a triphenyl ether moiety; the position of another one is at the serine oxygen in the C-terminal region of the aglycone.

[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.

[The antineoplastic antibiotic polypeptide 308 produced by Actinomadura recticatena. Its isolation and physicochemical properties]. / Protivoopukholevyi antibiotik-polipeptid 308, produtsiruemyi Actinomadura recticatena. Vydelenie i fiziko-khimicheskie svoistva.

A antitumor antibiotic belonging to the group of polypeptide antibiotics containing chromophore was isolated from the culture of Actinomadura recticatena Terekhova, Preobrazhenskaya et Galatenko, 1984, strain 308. Biosynthesis, isolation, physicochemical and biological properties of the antibiotic are described. The results of elemental analysis, the melting point, optical properties, UV, IR and NMR spectra and the data on acid hydrolysis showed that antibiotic 308 was most closely related to antibiotic BBM-928 A.

[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.