A new complex of anti-Gram-positive antibiotics was produced by the fermentation of Actinoplanes arizonaensis sp. nov. The antibiotics were recovered from the fermentation broth with Amberlite XAD-7 resin and from the mycelium by acetone lysis. UV, IR, MS and NMR spectral studies characterized these compounds as kalafungin-type antibiotics. They differ from other known members by an unusual oxidation pattern on the aromatic ring. They vary from one another by the degree and position of O-methylation on the aromatic ring and in the aliphatic portion of the molecules. The structure of one component was confirmed by X-ray diffraction analysis.

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The isolation of paulomycins A and B from fermentations of Streptomyces paulus has been reported earlier [J. Antibiotics 35: 285-294, 1982]. Further work on the antibiotics produced by S. paulus revealed the production of two paulomycin-related compounds, antibiotics 273a₁ and 273a₂ which were isolated by procedures involving extractions and chromatography over buffered silica gel.
Antibiotic 273a₁ which has been named paldimycin, was found to be a mixture of two materials, paldimycins A and B (antibiotics 273a_1α and 273a_1β). Similarly, antibiotic 273a₂ was found to consist of antibiotic 273a_2α and antibiotic 273a_2β. Paldimycin and antibiotic 273a₂, which are produced by addition of two or one molecules of N-acetyl-L-cysteine, respectively, to paulomycins A and B, are active vs. Gram-positive bacteria.

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Paldimycin (antibiotic 273a₁) and antibiotic 273a₂ as well as their individual components, paldimycins A (273a_1α) and B (273a_1β) and antibiotics 273a_2α and 273a_2β were synthesized from paulomycin, paulomycin A and paulomycin B, respectively, by reacting with N-acetyl-Lcysteine.
The semisynthetic antibiotics had chromatographic behavior (TLC, HPLC) and physical and chemical properties identical to the properties of the corresponding antibiotics produced by Streptomyces paulus.

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Two new antibiotics, iturin D and iturin E, were isolated from a strain of Bacillus subtilis producing iturin A. These compounds belong to the iturin group, the acid hydrolysates contained α-amino acids Asp₃, Glu₁, Pro₁, Ser₁ Tyr₁ and a mixture of n-C₁₄, iso-C₁₅, anteiso-C₁₅, iso-C₁₆ and n-C₁₆ β-amino acids.
They differ from iturin A by the presence of a free carboxyl group in iturin D and a carboxymethyl group in iturin E.

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Phlebiakauranol aldehyde and the corresponding alcohol were isolated from cultures of Punctularia atropurpurascens. The aldehyde but not the alcohol exhibited strong antifungal activity against several phytopathogens as well as antibacterial and cytotoxic activities. Two acetylated derivatives prepared from the aldehyde showed only very weak antifungal and antibacterial and moderate cytotoxic activities. We therefore assume, that the aldehyde group together with the high number of hydroxyl groups are responsible for the biological activity of the compound.

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A novel inhibitor of angiotensin I converting enzyme (ACE), designated K-13, was isolated from the culture broth of Micromonospora halophytica subsp. exilisia K-13. K-13 inhibited ACE non-competitively when hippuryl-L-histidyl-L-leucine was used as a substrate. The inhibition constant (Ki) was 0.349μM. K-13 hardly inhibited carboxypeptidase A, trypsin, α-chymotrypsin, leucine aminopeptidase, and aminopeptidase B even at a level of 61μM. When K-13 was administered intravenously to rats, it inhibited the pressor response to angiotensin I.

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The structure of K-13, a potent inhibitor of angiotensin I converting enzyme (ACE), was determined to be a cyclic dipeptide composed of tyrosine and an unusual diamino dicarboxylic acid, isodityrosine, by spectral and chemical studies of K-13 and its derivatives.

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The structures of the angucycline antibiotics urdamycin B (5), E (2) and F (9) were established by comparing of their spectra with those of urdamycin A (1). The structures of urdamycins C and D, the largest compounds of this series, are still incomplete (10 and 11), The aglycones urdamycinone C, D and E can be liberated by methanolysis of the corresponding urdamycins. The liberation of urdamycinone B (6) requires an alcohol-free medium, to prevent its rearrangement to the naphthacenequinone 7 or 8. The urdamycins differ from other O-glycoside series in their variety of aglycones.

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WF-10129 is an angiotensin converting enzyme (ACE) inhibitor produced by Doratomyces putredinis. IC₅₀ of the compound is 1.4×10^-8M for the ACE activity. WF-10129 was purified from cultured filtrate by successive ion exchange chromatography and HPLC. The chemical structure 1 was elucidated on the basis of spectroscopic and chemical evidence. The compound is a dipeptide composed of L-tyrosine and a novel amino acid. WF-10129 inhibits the pressor response of angiotensin I when administered intravenously at 0.3 mg/kg in rats.

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Several derivatives of 5-O-mycaminosyltylonolide substituted at C-23 have been prepared; these are 23-deoxy-23-C-methylene (3), 23-deoxy-23-C-(methoxycarbonylmethylene) (5), 23-deoxy-23-C-(ethoxycarbonylmethylene) (7), and 23-deoxy-23-C-(butoxycarbonylmethylene) (9), 23-deoxy-23-C-[(2E)-3-(ethoxycarbonyl)-2-propenylene] (11), and 23-deoxy-23-(dimethylaminoimino) (13), and 14-de(hydroxymethyl)-14-nitrile (16) derivatives. The key steps in these syntheses are the reactions of 2', 4'-di-O-acetyl-3-O-tert-butyldimethylsilyl-23-deoxy-23-oxo-5-O-mycaminosyltylonolide diethyl acetal (1) with several Wittig reagents, 1, 1-dimethylhydrazine and hydroxylamine. Antibacterial activities of these compounds are also described.

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A new type of thienamycin derivatives (3a-3j, 4a, 4b), having a monothioacetal or a thioacetal side chain at the C-2 position was prepared, and the susceptibility to renal dehydropeptidase-1 (DHP-1) and the antimicrobial activity of these compounds were determined. The structure-activity relationships of these derivatives are also discussed.

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Virginiamycin inducing factors (inducing material or inducing factor) of Streptomyces virginiae were isolated from the culture broth of this microbe and separated into three closely related compounds. They were named virginiae butanolides A, B and C and their structures were determined as 2-(1'-hydroxy-5'-methylhexyl)-3-(hydroxymethyl)butanolide (6), 2-(1'hydroxy-4'-methylhexyl)-3-(hydroxymethyl)butanolide (7) and 2-(1'-hydroxyhexyl)-3-(hydroxymethyl)butanolide (8), respectively. Part of their stereochemistry was also determined. Racemic virginiae butanolide C was synthesized to confirm their structures.

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The formation of sinefungin an antifungal and anti-parasitic nucleoside antibiotic was demonstrated in cell-free extracts from Streptomyces incarnatus. Incorporation studies as well as HPLC analysis showed that the immediate biosynthetic precursors of the antibiotic are L-arginine and ATP. The biosynthesis was optimal when the cell-free extract was prepared from 72 hours mycelium and incubated at least 80 minutes with arginine and ATP. The presence of dithiothreitol, pyridoxal phosphate and Mg²⁺ in the incubation mixture was also necessary. When a membrane fraction was incubated under the same conditions with ATP and L-arginine, sinefungin production was not observed. A working hypothesis is put forward to explain the biosynthesis of this antibiotic.

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OF4949-I and II inhibited aminopeptidase B from Ehrlich ascites carcinoma in a competitive way and the Ki value for both against L-arginine-β-naphthylamide was 8×10^-9M. Inhibition by I and II of various exopeptidases and endopeptidases was examined. OF4949-I and II both strongly inhibited leucine aminopeptidase and enkephalin-degrading aminopeptidase; I also inhibited enkephalinase B.
The inhibitory effects of various derivatives of I and II on aminopeptidase B activity, showed that the terminal amino and carboxamide groups are essential for activity.

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OF4949-I inhibited the growth of the solid form of IMC carcinoma and protected against pulmonary metastases of Lewis lung carcinoma. It also augmented the cytostatic activity of mouse peritoneal macrophages, the natural killer activity, and the antibody-dependent cell-mediated cytotoxicity of mouse spleen cells. This substance was not cytotoxic to cultured tumor or normal cells even at high concentrations. These results suggest that a cell-mediated immune response stimulated by this compound might account for its antitumor activity.

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The pseudo-oligosaccharides, validamycins, showed potent inhibitory activity against trehalase of Rhizoctonia solani while no significant inhibition was exhibited against cellulase, pectinase, chitinase, α-amylase, α- and β-glucosidases. In particular, validoxylamine A strongly inhibited trehalase in a competitive manner with a Ki value of 1.9×10^-9M. The uptake of the antibiotic into the cell and the amount of the intracellular trehalose were investigated by incubating the washed mycelia of R. solani with validamycins. It was found that validamycin A is transported into the cell and hydrolyzed therein by a β-glucosidase yielding validoxylamine A with greater inhibitory activity. Also validamycin A containing β-D-glucosyl residue is more favorably taken up into the cell than validamycin D containing α-D-glucosyl residue or their common aglycone, validoxylamine A. In addition, validamycin A suppressed the in vivo degradation of the intracellular trehalose at very low concentration of 0.1 μg/ml.

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The metabolism of benzylpenicillin (PCG) in isolated rat hepatocytes was investigated. The evidence of metabolizing activity for PCG in hepatic cells was obtained as follows; the disappearance rate of PCG from the incubation medium followed Michaelis-Menten kinetics and was dependent on the cellular protein concentration, while PCG did not disappear when it was incubated with cells denaturated by heat. The rate of disappearance of PCG was reduced significantly in the presence of the structural analogue of PCG such as phenoxymethylpenicillin in the incubation medium. The major metabolite of PCG was identified, by high performance liquid chromatographic analysis, to be penicilloic acid (PA) of PCG. A kinetic model describing the intra- and extra-cellular concentrations of PCG and PA was developed. The proposed model fitted well the time course of changes in the concentration of PCG and PA. The clearance of the uptake of PCG by isolated hepatocytes was evaluated to be about 23-times greater than that of metabolism of PCG.

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When bleomycin (BLM) was incubated with DNA at 37°C for 30 minutes in the presence of BLM-Cu(II) and cysteine, the DNA became more acid-soluble compared with the reaction without BLM-Cu(II). Superoxide dismutase did not suppress this increased DNA chain breakage. This combination of BLM-Cu(II) and cysteine did not enhance BLM-Fe(II)-induced DNA chain breakage, but caused the DNA chain breakage by inactive BLM-Fe(III). Combination of BLM-Fe(III) with BLM-Cu(II) and cysteine also caused production of malondialdehyde-like product from DNA. Anaerobic incubation of DNA with BLM-Fe(III) and BLM-Cu(I) followed by aerobic incubation produced malondialdehydelike product, but the incubation with CuCl instead of BLM-Cu(I) did not. These results suggest that activation of BLM-Fe(III) by BLM-Cu(II) and cysteine seems to be due to the reduction of BLM-Fe(III) to BLM-Fe(II) by BLM-Cu(I) formed in the reaction of BLM-Cu(II) and cysteine.

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The oral administration of forphenicinol increased the survival rate of both normal and immunodepressed mice intraperitoneally or mtratracheally infected with clinically isolated strains of Pseudomonas aeruginosa. The therapeutic effect of amikacin on intraperitoneal infection with P. aeruginosa was enhanced by combined use with forphenicinol.
Forphenicinol did not enhance the bactericidal activity of polymorphonuclear cells (PMN) towards P. aeruginosa in vitro, but enhanced it in vivo. In vitro study indicated that the macrophages taken from mice treated with forphenicinol or the cultured supernatant of these macrophages enhanced the bactericidal activity of PMN. The protective effect of forphenicinol against P. aeruginosa infection was thus suggested to be due to macrophage activation followed by the enhancement of the bactericidal activity of PMN.

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