This report describes new polyenes isolated from fermentations with Streptoverticillium sp. LL-30F848. Structure elucidation using a variety of spectroscopic techniques, including extensive NMR studies, revealed that these pentaene macrolides lacked the otherwise common hemiketal-tetrahydropyran and aminoglycoside moieties, but still carried a carboxylic acid group. The unambiguous assignment of NMR signals attributed to the olefinic region of the pentaenes was possible for the first time, and the relative stereochemistry of the macrolide was established according to ROESY correlations. Strevertene A is the principal pentaene of the antibiotic polyene complex produced.

Two novel heptadecaglycoside antibiotics, saccharomicins A (1) and B (2), were isolated from a new species of Saccharothrix. Their structures were determined by a combination of chemical degradation and spectroscopic methods. Saccharomicin B (2) was identified as N-(m,p-dihydroxycinnamoyl) taurine p-O-[alpha-4-epi-vancosaminopyranosyl( 1-4)-alpha-4-epi-vancosaminopyranosyl(1-->4)-alpha-digitoxopyranosyl(1-->4)-alpha-4-epi-vancosaminopyranosyl(1-->4)-alpha-digitoxopyranosyl(1-->3)-beta-fucopyranosyl(1-->4)-beta-saccharosaminopyranosyl(1-4)-alpha-digitoxopyranosyl( 1-->3)]-[-4-epi-vancosaminopyranosyl(1-->4)]-beta-fucopyranosyl(1-->4)-beta-saccharosaminopyranosyl(1-4)-alpha-rhamnopysyl(1-4)-beta-fucopyranosyl(1-4)-beta-saccharosaminopyranosyl(1-4)-beta-2-sulfate-fucopyranoside. Saccharomicin A (1) differs from saccharomicin B (2) only in the 10th sugar residue, where alpha-digitoxopyranosyl(1-3) is replaced with alpha-rhamnopyranosyl(1-->3). The novel amino sugar residue, designated saccharosamine, was identified by NMR spectroscopy and X-ray crystallography. Both saccharomicins A (1) and B (2) showed antimicrobial activity against Gram-positive bacteria.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Antibiotic 07F275 (1), produced by submerged fermentations of fungal culture LL-07F275, was isolated and characterized despite its inherent instability. Its UV spectrum was identical with that of nemotin, a member of the allenic polyacetylene family, but a molecular weight of 218 daltons indicated a new compound. Structure 1 was determined on the basis of spectroscopic evidence, particularly NMR. Since 1 is a thirteen carbon-containing allenic diyne, it is closely related to mycomycin.

Glycothiohexide alpha was recovered from the fermentation broth of a "Sebekia" sp. by mixed solvent extraction, selective precipitation and adsorption chromatography on Diaion HP-20. The amount of glycothiohexide cc present in the crude preparation was enriched by photolysis. Purification of glycothiohexide alpha was accomplished by repetitive countercurrent chromatography.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetection of phenanthroviridin aglycon in a UV mutant of Streptomyces murayamaensisMartha C. Cone, Awatef M. Hassan, Makarand P. Gore, Steven J. Gould, Donald B. Borders, and Mahender R. AlluriCite this: J. Org. Chem. 1994, 59, 7, 1923–1924Publication Date (Print):April 1, 1994Publication History Published online1 May 2002Published inissue 1 April 1994https://doi.org/10.1021/jo00086a056RIGHTS & PERMISSIONSArticle Views134Altmetric-Citations14LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (657 KB) Get e-Alerts Get e-Alerts

Ganefromycins are antibiotics produced by Streptomyces lydicus sp. tanzanius having commercial potential as performance enhancement agents for livestock. Ganefromycins are related to the elfamycin family of antibiotics but contain several unique chemical features which are the source of novel and unexpected chemistry. Reactions under mildly basic conditions resulted in the interconversion of ganefromycins alpha (1) and beta (2) by a 1,2-acyl migration. Strong base causes elimination of a trisaccharide whose structure was solved by single-crystal X-ray diffraction analysis of the triacetate of the reduced ring-opened triol. Ammonolysis yields the same rearranged product from either 1 or 2. Evidence is provided for the mechanism of this rearrangement involving elimination of the saccharide to form a transient alpha,beta-unsaturated carbonyl, Michael addition of ammonia, and intramolecular transacylation. Ozonolysis and acidic methanolysis were employed to obtain simplified compounds for structure determination. Ganefromycin beta fragments in warm acetic acid solution, releasing the long-chain amino acid. C-13 NMR data with assignments are provided for the degradation products.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The chemical structure of a novel thiopeptide antibiotic, glycothiohexide alpha (1), isolated from the fermentation broth of a "Sebekia" species was determined based on extensive 2D NMR studies, as well as, IR, UV, and mass spectral data. The chemical structure of glycothiohexide alpha is closely related to nosiheptide (3) and antibiotic S-54832A.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The antibacterial activity of the cyclic antibiotic LL-AO341 beta 1 was examined. The antibiotic was a narrow spectrum agent, effective principally against Gram-positive organisms. The intrinsic insusceptibility of Escherichia coli was due to exclusion of the drug by the outer membrane. The antibiotic was bactericidal against Staphylococcus aureus, and cell death was associated with lysis of the bacteria. The antibiotic did not specifically inhibit the synthesis of DNA, RNA, protein, lipid or peptidoglycan since these synthetic activities continued for several minutes after exposure to lethal concentrations of the antibiotic and then all abruptly ceased between about 8 and 15 minutes post antibiotic exposure. These results are consistent with the cytoplasmic membrane being the primary target for LL-AO341 beta 1. Mutants of S. aureus 8325-4 selected on 10- or 20-times the MIC of LL-AO341 beta 1 occurred spontaneously with a frequency of about 3 x 10(-6). A mutant expressing a 160-fold increase in the MIC of LL-AO341 beta 1 was obtained by exposing cultures to progressively increasing concentrations of the antibiotic. This mutant displayed no cross-resistance to other agents apart from telomycin (a structural analogue of LL-AO341 beta 1), apparently did not modify or degrade LL-AO341 beta 1 and had only a slightly longer doubling time than the parent strain.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The details of the structural assignment of the potent antitumor antibiotic, calicheamicin gamma-1I (6, C55H74IN3O21S4), is reported. Methanolysis studies on 6 and N-acetylcalicheamicin gamma-1I (8, C57H76IN3022S4) permitted the structural assignment of the glycosidic chain. Details of the spectral analysis supporting the assignments of the 3-O-methyl-alpha-L-rhamnopyranoside (D-ring) and the methyl 2,4-dideoxy-3-O-methyl-4-(N-acetyl-N-ethylamino)-a-L-xylopyranoside (E-ring) is reported. The structure of calicheamicinone (32, C18H17NO5S3), containing a bicyclo[7.3.1 ] tridec-9-ene-2,6-diyne system and a methyl trisulfide, was elucidated by a series of chemical degradation studies, which included an unexpected free radical cycloaromatization reaction. The presence of 4,6-dideoxy-4-(hydroxyamino)-beta-D-glucopyranoside (A-ring) and its N-O glycosidic linkage to the thio sugar (B-ring) was ascertained by X-ray crystallography of 24 (C36H40INO13S2), a degradation product of 6. The chemical structures of calicheamicins beta-1Br (1), gamma-1Br (2), alpha-2I (3), alpha-3I (4), beta-1I (5), and delta-1I (7) were assigned by correlating their H-1 and C-13 NMR data with that of calicheamicin gamma-1I. By tracking the biological activities of the degradation products, the enediyne system of calicheamicinone was shown to be essential for the DNA-damaging abilities of the calicheamicins. A mechanism whereby the enediyne could be triggered to cyclize via a 1,4-diyl, the putative DNA cleaving species, is proposed.

The biosynthesis of citreamicin 1 has been studied by feeding C-13- and O-18-labelled precursors to Micromonospora citrea cultures. C-13-NMR spectroscopic analysis of the enriched products demonstrated a labelling pattern indicating that the antibiotic is derived from a polyketide which undergoes rearrangement by a mechanism unique for xanthone biosynthesis.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCalicheamicins: discovery, structure, chemistry, and interaction with DNAMay D. Lee, George A. Ellestad, and Donald B. BordersCite this: Acc. Chem. Res. 1991, 24, 8, 235–243Publication Date (Print):August 1, 1991Publication History Published online1 May 2002Published inissue 1 August 1991https://doi.org/10.1021/ar00008a003RIGHTS & PERMISSIONSArticle Views909Altmetric-Citations185LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts