The isolation of lavendamycin (1) an antibiotic closely related to streptonigrin (2) is described. Details of the taxonomic description ofS. lavendulae(strain C-22, 030), production of lavendamycin, its isolation and the biological activity are given.

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Streptomyces echinosporus MK-213 produces a novel antibiotic echinosporin (XK-213). Isolation of echinosporin was performed by absorption on activated carbon under acidic conditions and then eluted by aqueous acetone. The compound crystallized from methanol is a water soluble white solid composed of C₁₀H₉NO₅. Echinosporin exhibits weak antibacterial activities against Gram-positive and -negative microorganisms and it shows antitumor activity.

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An actinomycete strain IM7912T was found to produce cadeguomycin, a new nucleoside analog antibiotic, together with tubercidin. Morphological, cultural and physiological studies showed that the organism belongs to the species Streptomyces hygroscopicus. Comparisons with S. hygroscopicus ISP 5578 revealed that both strains possess similar characteristics except for production of yellow or brownish yellow soluble pigment in some media. Cadeguomycin was isolated from the culture filtrate, separated from tubercidin, and purified.

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Cadeguomycin, a new nucleoside analog antibiotic, has been purified as colorless needle crystals by recycling preparative HPLC. The antibiotic, C₁₂H₁₄O₇N₄, mp 231-239°C (dec.), FD-MS: m/z 326 (M⁺); is a weakly acidic substance, showing UV λ^H₂O_max (ε) 232 (19677), 272 (6881) and 298 nm (7607), and IR ν^KBr_max 1650 (C=O) and 3420 (NH or OH) cm^-1. The UV spectrum is similar to other pyrrolo[2, 3-d]pyrimidines. The structure of cadeguomycin, 2-amino-3, 4-dihydro-4-oxo-7-β-D-ribofuranosyl-7H-pyrrolo[2, 3-d]pyrimidine-5-carboxyalcicid, has been elucidated by ¹H NMR and ¹³C NMR in comparison with other pyrrolo[2, 3-d]pyrimidines and their nucleosides.

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Paulomycin A, C₃₄H₄₆N₂O₁₇S and paulomycin B, C₃₃H₄₄N₂O₁₇S are two antibiotics produced by Streptomyces paulus strain 273 (UC 5142). Both antibiotics, which are mainly active against a variety of Gram-positive bacteria, contain an isothiocyanate group and in this respect they are related to senfolomycins A and B and proceomycin.

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A series of novel monocyclic β-lactam antibiotics were isolated from a strain of Agrobacterium radiobacter. The compounds show weak antibacterial activity but are highly stable to hydrolysis by β-lactamases.

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βAgrobacterium radiobacter produces a mixture of monocyclic β-lactam antibiotics that belong to a recently discovered class called monobactams. Five components of this mixture have been isolated and structures 6-10 assigned.

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Bacillomycin F, a new family of iturin group antibiotics, was isolated from Bacillus subtilis. It shows a potent antifungal activity and a narrow spectrum against bacteria. Acid hydrolysis gave a peptide moiety which contains 7 mole of amino acids: D-Asp₂, L-Glu₁, L-Thr₁, L-Pro₁, D-Tyr₁ and a lipid moiety which is a mixture of two main long chain n-amino acids: β-amino-14-methylpentadecanoic acid (58%) and 3-amino-14-methylhexadecanoic acid (23%).

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The glycosidation products of O-α-L-cinerulosyl-(1→4)- O-(3-O-acetyl-2-deoxy-a-Lfucosyl)-(1→4)- α, β-L-rhodosamine with aklavinone, daunomycinone, adriamycinone and carminomycinone were synthesized and the resulting products were deacylated, yielding anthracyclines having the trisaccharide. We further synthesized N-monomethyl and N-didemethyl derivatives of daunomycinone trisaccharide by photolysis with sunlight. 3"-O-Acyl derivatives of daunomycinone, carminomycinone and aklavinone glycosides showed a marked antitumor activity against L1210 leukemia in mice with ILS 110, 86 and 86%, respectively, while 3"-Oacetyladriamycinone glycoside was highly toxic with a ILS of 44%.

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The synthesis and in vitro activity of 7α-methoxy-7β-vinylenethioacetamido cephalosporins with various substituents at the 3-position are described. These cephalosporins showed good activity against β-lactamase producing Gram-negative bacteria. 7α-Methoxy-7-[(Z)-β-cyanovinylenethioacetamido]-3-[(1-methyl-1H-tetrazol-5-yl)thiomethyl]-3-cephem-4-carboxylic acid (3) was several times more active in vitro than cefoxitin and comparable to cefmetazole.

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We report here a total synthesis of nocardicin A. The antibiotic was obtained as a mixture of diastereoisomers that possessed approximately one quarter of the antibacterial activity of the naturally occurring material.

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Streptomyces erythreus NRRL 2338, the erythromycin producing microorganism, contains extrachromosomal (plasmid) DNA. Four different plasmids, pSE1, pSE2, pSE4 and pSE6 present in the wild-type strain have characteristic mobilities on agarose gel electrophoresis, molecular weights and restriction endonuclease digestion patterns. Treatment of the wildtype strain with ethidium bromide or acridine orange gave two variants, one that could not convert erythronolide B to 3 (α)-mycarosylerythronolide B and another that produced 2-3 times more erythromycin A than the parental strain. Although the plasmid DNA profile of these two variants is different from the wild-type strain, it is not possible to conclude that any of the structural genes for erythromycin biosynthesis are located on the plasmids of S. erythreus NRRL 2338.

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Synergistic effects of peptide and macrolide antibiotics against Pseudomonas aeruginosa were investigated in vitro and in vivo. Synergistic effects were evaluated by estimating the number of viable bacteria at varying intervals in the logarithmic growth phase. These bacteria were treated concurrently with polymyxin B (PL) at the final concentration of 1.56 U/ml and with 9, 3"-di-O-acetylmidecamycin (MOM) at varying concentrations. Synergistic effect was observed when PL was used with MOM at 3.13 and 12.5 μg/ml respectively. When MOM at 50 μg/ml was used with PL, the viable bacterial count was reduced to below 1/300 of the control to which PL alone had been added. Thus, the synergistic effect was remarkable. Similar results were obtained when colistin methanesulfonate (CL) was used instead of PL. Subsequently, attempts were made to determine if this action could also be found in in vivo experiments using mice. PL or CL was injected intramuscularly and midecamycin (MDM) or MOM was administered once or repeatedly by the oral route. Simultaneously, Pseudomonas aeruginosa strain IFO 3455 was inoculated intraperitoneally to mice. In the case of treatment once or repeatedly using both PL and MDM or MOM, the survival rate of infected mice increased significantly compared to single treatment by PL alone. Thus, the synergistic effects were demonstrated in four experiments. (The significance levels for the experiments were P=0.070, 0.015, 0.042 and 0.024). Similar results were obtained when strain No. 5 was used to infect mice (P=0.0096, 0.0027). When CL and MOM were given to mice once prior to infection with strain No. 5, synergistic effects were obtained as well (P=0.010, 0.034).

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Ninety-five streptomycin-nonproducing mutants derived from Streptomyces griseus FT-1 by UV-irradiation could be classified into major two classes by cosynthesis tests. Class I mutants (42 strains) were mutants blocked in the pathway of streptomycin biosynthesis while class II mutants (49 strains) required a factor for streptomycin biosynthesis which was excreted by the parental or class I mutant strains. The factor could be replaced by synthetic A-factor (2S-isocapryloyl-3S-hydroxymethyl-γ-butyrolactone) which restored both streptomycin biosynthesis and spore formation in the class II mutants. A-Factor deficient mutants were obtained from several strains of S. griseus and S. bikiniensis at high frequency by treatment with acridine orange or incubation at high temperature. A mutant whose streptomycin biosynthesis was independent of A-factor deficiency was found. The production of A-factor was distributed among various species of actinomycetes.

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Protoplasts of two different auxotrophic mutants of Streptomyces lavendulae were fused with polyethylene glycol (PEG) 1000, and allowed to regenerate on selective media. Prototrophic colonies overwhelmed other types of recombinants on any selective media. These prototrophic strains were stable after successive isolation. These results suggest that stable diploid cells were formed by cell fusion, which differed from the case of S. coelicolor.

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