Ferroverdins, inhibitors of cholesteryl ester transfer protein produced by Streptomyces sp. WK-5344. I. Production, isolation and biological properties.

Streptomyces sp. WK-5344, a soil isolate, was found to produce structurally related inhibitors of cholesteryl ester transfer protein (CETP). New active compounds, designated ferroverdins B and C, were isolated along with known ferroverdin A from the fermentation broth by solvent extraction, ODS column chromatography and silica gel column chromatography. All ferroverdins showed a dose-dependent inhibitory activity against human CETP. The IC50 values were 21, 0.62 and 2.2 microM for ferroverdins A, B and C, respectively, indicating that ferroverdin B is one of the most potent CETP inhibitors of microbial origin.

Chloropeptins, new anti-HIV antibiotics inhibiting gp120-CD4 binding from Streptomyces sp. I. Taxonomy, fermentation, isolation, and physico-chemical properties and biological activities.

Chloropeptins I and II, which are gp120-CD4 binding inhibitors, were isolated as pale yellow-brown powders from the mycelia of a soil actinomycete, Streptomyces sp, WK-3419. Their physico-chemical properties showed that they are chlorinated peptides. Chloropeptin I (C61H45N7O15Cl6) is a novel compound, but chloropeptin II was identified as complestatin. Both compounds inhibited gp120-CD4 binding (IC50: 1.3 and 2.0 microM, respectively), the cytopathic effect of HIV in MT-4 cells (EC50: 1.6 and 1.7 microM, respectively) and syncytium formation in co-cultured HIV-1-infected and uninfected MOLT-4 cells (IC50. 0.5 and 1.1 microM, respectively). Chloropeptin I was synergistic in the inhibition of the cytopathic effect when combined with other anti-HIV drugs such as zidovudine (AZT), didanosine (ddI), zalcitabine (ddC) and nevirapine.

Louisianins A, B, C and D: non-steroidal growth inhibitors of testosterone-responsive SC 115 cells. II. Physico-chemical properties and structural elucidation.

New non-steroidal growth inhibitors of testosterone-responsive SC 115 cells, louisianins A (MW: 189; C11H11NO2), B (MW: 191; C11H13NO2), C (MW: 173; C11H11NO) and D (MW: 173; C11H11NO) were isolated from the cultured broth of Streptomyces sp. WK-4028. Their structures were determined on the basis of spectroscopic data. The structure of louisianin A in particular was confirmed by X-ray crystallographic analysis. The four compounds commonly possess a unique pyrindine skeleton in the molecule.

Louisianins A, B, C and D: non-steroidal growth inhibitors of testosterone-responsive SC 115 cells. I. Taxonomy, fermentation, isolation and biological characteristics.

In the course of screening for non-steroidal growth inhibitors of testosterone-responsive Shionogi carcinoma 115 cells, louisianins A, B, C and D, were isolated from fermentation broth of Streptomyces sp. WK-4028. Louisianin A remarkably inhibited the growth of SC 115 cells in the presence of 10(-7) M testosterone at an IC50 value of 0.6 microgram/ml, whereas, no inhibition was observed on the other cell lines. Furthermore, inhibitory activity of testosterone 5 alpha-reductase and antimicrobial activity have not been observed at a concentration of 50 micrograms/ml and 1,000 micrograms/ml, respectively.

Diolmycins, new anticoccidial agents produced by Streptomyces sp. I. Production, isolation and physico-chemical and biological properties.

Streptomyces sp. WK-2955, a soil isolate, was found to produce a series of new anticoccidial compounds. Four active compounds, designated diolmycins A1, A2, B1 and B2, were isolated from the fermentation broth of the producing strain by solvent extraction, silica gel column chromatography, gel filtration on Sephadex LH-20, and preparative HPLC. Diolmycins inhibited the growth of Eimeria tenella in an in vitro assay system using BHK-21 cells as a host. No schizont in the cells was observed at concentrations of 0.02-2.0 micrograms/ml for diolmycin A1, at 0.2-2.0 micrograms/ml for diolmycin A2, and at 20 micrograms/ml for diolmycins B1 and B2.

Studies on a novel antitumor antibiotic, phenazinomycin: taxonomy, fermentation, isolation, and physicochemical and biological characteristics.

A new antibiotic, phenazinomycin (C27H32N2O, MW 400), was isolated from the cultural mycelium of Streptomyces sp. WK-2057. This antibiotic possesses antibacterial activities against Gram-positive bacteria in vitro, direct cytotoxic activities against HeLa S3, P388 and P388 doxorubicin-resistant cells in vitro and antitumor activities against experimental murine tumors in vivo.

Ahpatinins, new acid protease inhibitors containing 4-amino-3-hydroxy-5-phenylpentanoic acid.

A soil isolate, Streptomyces sp. WK-142, was found to produce new acid protease inhibitors, ahpatinins A, B, D, E, F and G active against pepsin and renin. Ahpatinin C was found to be identical with pepstatin A. The structure determinations were based on mass spectral data. Four of the compounds contain the unusual amino acid, 4-amino-3-hydroxy-5-phenylpentanoic acid as a building component.

Use of a computer to group actinomycetes for studies on the ecology of soil microorganisms.

A computer program has been prepared for grouping soil actinomycetes into cluster groups based on the presence or absence of aerial mycelium, the color of soluble pigment, and the shade of color of surface and reverse mycelium. The program automatically condenses cultures with wide ranges of characteristics into a limited number of groups and provides a permanent record so that comparisons can be made among experiments performed over a span of time. The program permits the grouping of large numbers of cultures with minimal laboratory effort and has proven useful in defining some of the ecological factors that lead to changed actinomycete populations in soils.

Studies on the ecology of West Australian actinomycetes: Factors which influence the diversity and types of actionomycetes in Australian soils.

A statistical technique has been employed to study the effects of various environmental factors in altering the actinomycete populations of soils located in the western part of Australia. Over 12,000 actinomycetes obtained at 28 different locations were included in the evaluation. Among factors that had a significant influence were the geographic area at which the sample was taken, the nature of plant rhizosphere, and a rainstorm. Seasonal changes in population did occur, but there was considerable stability of population with time. Although marked differences occurred in types of actinomycetes present among different geographic locations, multiple samples taken within a location at distances of 30 cm or greater showed marked similarity in populations. There were varied degrees of diversity among the populations studied. The population that developed after a rainstorm was low in diversity, whereas the populations of root rhizospheres were as diverse as those of plant-free soil-litter areas. In assessing the ecology of soil actinomycetes, it is important to consider the degree of change in population induced by an environmental factor and also its effect on diversity, since the effects may be complementary or may be opposite in nature.

Patenting of hybridomas and genetically engineered microorganisms.

Many new technologies arrived at through basic research have practical applications. Two recent breakthroughs in microbiology, recombinant DNA techniques and hybridoma techniques, will permit designing cells for specific practical purposes resulting in new products or functions of commercial significance. The unique cell or its usefulness, or both, may satisfy the requirements of a patentable invention, i.e. an inventive act having utility and novelty. Ownership of such patents permits recovery of expenses incurred in the invention process and investment for all concerned in additional research. An integral part of the patenting process is submission of the new cell to an official repository, an outstanding example of which is The American Type Culture Collection.

Natural products from microorganisms.

Microorganisms are capable of producing natural products with widely divergent chemical structures. Greatest attention in the past has been paid to natural products that have antibiotic properties. Natural products accumulate in fermentation broths during secondary metabolism, a characteristic of the incomplete metabolic control operative in growth-inhibited microorganisms. With this general mechanism of biosynthesis, the natural products synthesized by microorganisms would be expected to have a broad range of pharmacological activities. The directed screening for non-antibiotic natural products has been of limited scope. The expectation that new compounds of interest would be found has been validated. The pharmacologically active natural products provide previously unrecognized structures as tools for fundamental research programs, as well as offering the possibility of direct use in medicine or in industrial processes.

Cefoxitin and cephamycins: microbiological studies.

The cephamycins are a family of beta-lactam antibiotics that are produced by actinomycetes and are structurally similar to the cephalosporins. They are characterized by the presence of a 7-alpha-methoxyl group, which confers unusually high resistance to beta-lactamases. Cefoxitin, the first semisynthetic cephamycin, is resistant to almost all beta-lactamases. Cefoxitin retains the 3-carbamoyl group of cephamycin C and thus has excellent metabolic stability. Cefoxitin is bactericidal and almost devoid of any inoculum effect. Active against many cephalothin-resistant gram-negative bacteria, cefoxitin demonstrates a very broad spectrum that includes indole-positive Proteus and many strains of Serratia. In contrast to that of the cephalosporins, cefoxitin's spectrum of activity against anaerobic pathogens includes Bacteroides fragilis. The therapeutic effectiveness of cefoxitin in experimental infections in mice confirms the excellent characteristics of this semisynthetic cephamycin and indicates that it should be a very valuable agent for treatment of bacterial infections.

Thienamycin, a new beta-lactam antibiotic. I. Discovery, taxonomy, isolation and physical properties.

A new beta-lactam antibiotic, named thienamycin, was discovered in culture broths of Streptomyces MA4297. The producing organism, subsequently determined to be a hitherto unrecognized species, is designated Streptomyces cattleya (NRRL 8057). The antibiotic was isolated by adsorption on Dowex 50, passage through Dowex 1, further chromatography on Dowex 50 and Bio-Gel P2, and final purification and desalting on XAD-2. Thienamycin is zwitterionic, has the elemental composition C11H16N2O4S (M.W. = 272.18) and possesses a distinctive UV absorption (lambda max = 297 nm, epsilon = 7,900). Its beta-lactam is unusually sensitive to hydrolysis above pH8 and to reaction with nucleophiles such as hydroxylamine, cysteine and, to a lesser degree, the primary amine of the antibiotic itself. The latter reaction results in accelerated inactivation at high antibiotic concentrations.