RESUMO
The microbial production, isolation, and structure elucidation of four new napyradiomycin congeners (1-4) is reported. The structures of these compounds, which are new additions to the marine-derived meroterpenoids, were defined by comprehensive spectroscopic analysis and by X-ray crystallography. Using fluorescence-activated cell sorting (FACS) analysis, napyradiomycins 1-4 were observed to induce apoptosis in the colon adenocarcinoma cell line HCT-116, indicating the possibility of a specific biochemical target for this class of cytotoxins.
Assuntos
Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Naftoquinonas/isolamento & purificação , Naftoquinonas/farmacologia , Antineoplásicos/química , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Células HCT116 , Humanos , Biologia Marinha , Conformação Molecular , Estrutura Molecular , Naftoquinonas/química , Ressonância Magnética Nuclear Biomolecular , EstereoisomerismoRESUMO
Cyanosporasides are marine bacterial natural products containing a chlorinated cyclopenta[a]indene core of suspected enediyne polyketide biosynthetic origin. Herein, we report the isolation and characterization of novel cyanosporasides C-F (3-6) from the marine actinomycetes Salinispora pacifica CNS-143 and Streptomyces sp. CNT-179, highlighted by the unprecedented C-2' N-acetylcysteamine functionalized hexose group of 6. Cloning, sequencing, and mutagenesis of homologous ~50 kb cyanosporaside biosynthetic gene clusters from both bacteria afforded the first genetic evidence supporting cyanosporaside's enediyne, and thereby p-benzyne biradical, biosynthetic origin and revealed the molecular basis for nitrile and glycosyl functionalization. This study provides new opportunities for bioengineering of enediyne derivatives and expands the structural diversity afforded by enediyne gene clusters.
Assuntos
Actinobacteria/química , Actinobacteria/genética , Glicosídeos/química , Glicosídeos/genética , Indenos/química , Produtos Biológicos/química , Produtos Biológicos/metabolismo , Enedi-Inos/química , Genes Bacterianos , Família Multigênica , Streptomyces/química , Streptomyces/genéticaRESUMO
Licensed to kill: A new antibiotic, anthracimycin (see scheme), produced by a marine-derived actinomycete in saline culture, shows significant activity toward Bacillus anthracis, the bacterial pathogen responsible for anthrax infections. Chlorination of anthracimycin gives a dichloro derivative that retains activity against Gram-positive bacteria, such as anthrax, but also shows activity against selected Gram-negative bacteria.
Assuntos
Actinobacteria , Antraz/tratamento farmacológico , Antibacterianos/farmacologia , Bacillus anthracis/efeitos dos fármacos , Sedimentos Geológicos/microbiologia , Bactérias Gram-Positivas/efeitos dos fármacos , Policetídeos/farmacologia , Poluentes Químicos da Água/química , Antraz/microbiologia , Antibacterianos/química , Sedimentos Geológicos/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Policetídeos/química , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Reported is the structure and biosynthesis of ansalactam A, an ansamycin class polyketide produced by an unusual modification of the polyketide pathway. This new metabolite, produced by a marine sediment-derived bacterium of the genus Streptomyces , possesses a novel spiro γ-lactam moiety and a distinctive isobutyryl polyketide fragment observed for the first time in this class of natural products. The structure of ansalactam A was defined by spectroscopic methods including X-ray crystallographic analysis. Biosynthetic studies with stable isotopes further led to the discovery of a new, branched chain polyketide synthase extender unit derived from (E)-4-methyl-2-pentenoic acid for polyketide assembly observed for the first time in this class of natural products.
Assuntos
Antibacterianos/biossíntese , Antibacterianos/química , Organismos Aquáticos/metabolismo , Policetídeos/química , Rifabutina/análogos & derivados , Rifabutina/química , Rifabutina/metabolismo , Streptomyces/metabolismo , Produtos Biológicos/química , Produtos Biológicos/metabolismo , Sedimentos Geológicos/microbiologia , Policetídeo Sintases/química , Policetídeo Sintases/metabolismo , Policetídeos/metabolismoRESUMO
Reported herein is the isolation and structure elucidation of three highly modified peptides, actinoramides A-C (1-3), which are produced by a marine bacterium closely related to the genus Streptomyces. The planar structures of the actinoramides, which are composed of the unusual amino acids 2-amino-4-ureidobutanoic acid and 4-amino-3-hydroxy-2-methyl-5-phenylpentanoic acid, were assigned by chemical transformations and by interpretation of spectroscopic data, while the absolute configuration of these new peptides were defined by application of the advanced Marfey's and Mosher's methods.
RESUMO
The genetic architecture of atrial fibrillation (AF) encompasses low impact, common genetic variants and high impact, rare variants. Here, we characterize a high impact AF-susceptibility allele, KCNQ1 R231H, and describe its transcontinental geographic distribution and history. Induced pluripotent stem cell-derived cardiomyocytes procured from risk allele carriers exhibit abbreviated action potential duration, consistent with a gain-of-function effect. Using identity-by-descent (IBD) networks, we estimate the broad- and fine-scale population ancestry of risk allele carriers and their relatives. Analysis of ancestral migration routes reveals ancestors who inhabited Denmark in the 1700s, migrated to the Northeastern United States in the early 1800s, and traveled across the Midwest to arrive in Utah in the late 1800s. IBD/coalescent-based allele dating analysis reveals a relatively recent origin of the AF risk allele (~5000 years). Thus, our approach broadens the scope of study for disease susceptibility alleles to the context of human migration and ancestral origins.
Assuntos
Fibrilação Atrial/genética , Predisposição Genética para Doença/genética , Canal de Potássio KCNQ1/genética , Mutação de Sentido Incorreto , Polimorfismo de Nucleotídeo Único , Potenciais de Ação , Alelos , Dinamarca , Emigrantes e Imigrantes , Feminino , Genótipo , Geografia , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Masculino , Pessoa de Meia-Idade , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/fisiologia , Linhagem , Fatores de Risco , UtahRESUMO
Cultivation of actinomycete strain CNQ-418, retrieved from a deep ocean sediment sample off the coast of La Jolla, CA, has provided marinopyrroles A-F. Sharing just 98% 16S rRNA gene sequence identity with S. sannurensis, the strain likely represents a new Streptomyces species. The metabolites contain an unusual 1,3'-bipyrrole core decorated with several chlorine and bromine substituents and possess marked antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). The congested N,C-biaryl bond establishes an axis of chirality that, for marinopyrroles A-E, is configurationally stable at room temperature. Moreover, the natural products are fashioned strictly in the M-configuration. The Paal-Knorr condensation was adapted for the synthesis of the 1,3'-bipyrrole core. Halogenation of this material with N-bromosuccinimide cleanly furnished the 4,4',5,5'-tetrahalogenated core that characterizes this class of marine-derived metabolites.
Assuntos
Antibacterianos/farmacologia , Pirróis/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Cristalografia por Raios X , Testes de Sensibilidade Microbiana , Modelos Moleculares , Estrutura Molecular , Pirróis/síntese química , Pirróis/química , EstereoisomerismoRESUMO
Fijiolide A, a potent inhibitor of TNF-alpha-induced NFkappaB activation, along with fijiolide B, were isolated from a marine-derived bacterium of the genus Nocardiopsis. The planar structures of fijiolides A (1) and B (2) were elucidated by interpretation of 2D NMR spectroscopic data, while the absolute configurations of these compounds were defined by interpretation of circular dichroism and 2D NMR data combined with application of the advanced Mosher's method. Fijiolides A and B are related to several recently isolated chloroaromatic compounds, which appear to be the Bergman cyclization products of enediyne precursors. Fijiolide A reduced TNF-alpha-induced NFkappaB activation by 70.3%, with an IC(50) value of 0.57 micro-M. Fijiolide B demonstrated less inhibition, only 46.5%, without dose dependence. The same pattern was also observed with quinone reductase (QR) activity: fijiolide A was found to induce quinone reductase-1 (QR1) with an induction ratio of 3.5 at a concentration of 20 microg/mL (28.4 microM). The concentration required to double the activity was 1.8 microM. Fijiolide B did not affect QR1 activity, indicating the importance of the nitrogen substitution pattern for biological activity. On the basis of these data, fijiolide A is viewed as a promising lead for more advanced anticancer testing.
Assuntos
Actinomycetales/química , Glicosídeos/isolamento & purificação , Glicosídeos/farmacologia , NF-kappa B/efeitos dos fármacos , Fator de Necrose Tumoral alfa/farmacologia , Animais , Relação Dose-Resposta a Droga , Glicosídeos/química , Humanos , Biologia Marinha , Camundongos , Estrutura Molecular , NAD(P)H Desidrogenase (Quinona)/metabolismo , NF-kappa B/metabolismo , Ressonância Magnética Nuclear BiomolecularRESUMO
Six new anthraquinone-γ-pyrones, saliniquinones A-F (1-6), which are related to metabolites of the pluramycin/altromycin class, were isolated from a fermentation broth of the marine actinomycete Salinispora arenicola (strain CNS-325). Their structures were determined by analysis of one- and two-dimensional NMR spectroscopic and high-resolution mass spectrometric data. The relative and absolute configurations of compounds 1-6 were determined by analysis of NOESY NMR spectroscopic data and by comparison of circular dichroism and optical rotation data with model compounds found in the literature. Saliniquinone A (1) exhibited potent inhibition of the human colon adenocarcinoma cell line (HCT-116) with an IC50 of 9.9 × 10-9 M. In the context of the biosynthetic diversity of S. arenicola, compounds 1-6 represent secondary metabolites that appear to be strain specific and thus occur outside of the core group of compounds commonly observed from this species.
RESUMO
Two new polyene macrolides, marinisporolides A and B (1, 2), were isolated from the saline culture of the marine actinomycete, strain CNQ-140, identified as a member of the new marine genus Marinispora. The marinisporolides are 34-membered macrolides composed of a conjugated pentaene and several pairs of 1,3-dihydroxyl functionalities. Marinisporolide A (1) contains a bicyclic spiro-bis-tetrahydropyran ketal functionality, while marinisporolide B (2) is the corresponding hemiketal. The structures of these new compounds were assigned by combined spectral and chemical methods including extensive 2D NMR experiments and correlations of (13)C NMR data with Kishi's Universal NMR Database. Chemical modifications, including methanolysis, acetonide formation, and application of the modified Mosher method, provided the full stereostructures of these molecules. Three additional macrolides, marinisporolides C-E (3-5), which are olefin geometric isomers of marinisporolide A (1), were also isolated and their structures defined. Under room light, marinisporolides A and B readily photoisomerize to C-E indicating that they are most likely produced by photochemical conversion during the cultivation or isolation procedures. Although polyenes, marinisporolides A (1) and B (2) showed weak to no antifungal activity against Candida albicans.
Assuntos
Actinobacteria/química , Macrolídeos/química , Macrolídeos/isolamento & purificação , Polienos/química , Polímeros/química , Alcenos/química , Isomerismo , Espectroscopia de Ressonância MagnéticaRESUMO
Analysis of the full genome of an environmentally unique, halotolerant Streptomyces sp. strain GSL-6C, isolated from the Great Salt Lake, revealed a gene cluster encoding the biosynthesis of the salinipeptins, d-amino-acid-containing members of the rare linaridin subfamily of ribosomally synthesized and post-translationally modified peptides (RiPPs). The sequence organization of the unmodified amino acid residues in salinipeptins A-D (1-4) were suggested by genome annotation, and subsequently, their sequence and post-translational modifications were defined using a range of spectroscopic techniques and chemical derivatization approaches. The salinipeptins are unprecedented linaridins bearing nine d-amino acids, which are uncommon in RiPP natural products and are the first reported in the linaridin subfamily. Whole genome mining of GSL-6C did not reveal any homologues of the reported genes responsible for amino acid epimerization in RiPPs, inferring new epimerases may be involved in the conversion of l- to d-amino acids. In addition, the N-oxide and dimethylimidazolidin-4-one moieties in salinipeptins B and C, which are modified from N, N-dimethylalanine, are unknown in bacterial peptides. The three-dimensional structure of salinipeptin A, possessing four loops generated by significant hydrogen bonding, was established on the basis of observed nuclear Overhauser effect (NOE) correlations. This study demonstrates that integration of genomic information early in chemical analysis significantly facilitates the discovery and structure characterization of novel microbial secondary metabolites.
Assuntos
Aminoácidos/química , Genômica/métodos , Peptídeos/química , Ribossomos/química , Streptomyces/química , Alanina/análogos & derivados , Alanina/química , Óxidos N-Cíclicos/química , Família Multigênica , Conformação Proteica , Processamento de Proteína Pós-Traducional , Streptomyces/genéticaRESUMO
[structure: see text] Two new cyclic peptides, thalassospiramides A and B (1 and 2), were isolated from a new member of the marine alpha-proteobacterium Thalassospira. The thalassospiramides, the structures of which were assigned by combined spectral and chemical methods, bear unusual gamma-amino acids and show immunosuppressive activity in an interleukin-5 production inhibition assay (IC50 = 5 muM for thalassospiramide B).
Assuntos
Imunossupressores/química , Peptídeos Cíclicos/química , Rhodospirillaceae/química , Aminação , Animais , Hidroxilação , Imunossupressores/metabolismo , Imunossupressores/farmacologia , Linfócitos/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Camundongos , Estrutura Molecular , Oceanos e Mares , Ácidos Pentanoicos/química , Peptídeos Cíclicos/biossíntese , Peptídeos Cíclicos/farmacologia , Rhodospirillaceae/metabolismoRESUMO
[structure: see text] Two structurally novel cyclopenta[a]indene glycosides, cyanosporasides A and B (1 and 2) have been isolated from the culture broth of a new species of the obligate marine actinomycete genus Salinispora. The structures and absolute stereochemistries of these compounds were determined by spectral and chemical methods. The cyanosporasides possess a new 3-keto-pyranohexose sugar as well as a cyano- and chloro-substituted cyclopenta[a]indene ring system. The cyanosporasides are proposed to be cyclization products of an enediyne precursor.
Assuntos
Actinobacteria/química , Glicosídeos/química , Glicosídeos/isolamento & purificação , Indenos/química , Indenos/isolamento & purificação , Ciclização , Biologia Marinha , Estrutura MolecularRESUMO
[structure: see text] Analysis of the fermentation broth of a strain of the marine actinomycete Salinispora tropica has led to the isolation of two unprecedented macrolides, sporolides A (1) and B (2). The structures and absolute stereochemistries of both metabolites were elucidated using a combination of NMR spectroscopy and X-ray crystallography.
Assuntos
Actinobacteria/química , Macrolídeos/química , Macrolídeos/isolamento & purificação , Cristalografia por Raios X , Enterococcus faecium/efeitos dos fármacos , Humanos , Macrolídeos/farmacologia , Biologia Marinha , Resistência a Meticilina/efeitos dos fármacos , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Staphylococcus aureus/efeitos dos fármacos , Células Tumorais Cultivadas , Resistência a Vancomicina/efeitos dos fármacosRESUMO
Low-nutrient media and long incubation times facilitated the cultivation of 20 taxonomically diverse Gram-negative marine bacteria within the phyla Bacteroidetes and Proteobacteria. These strains comprise as many as three new families and include members of clades that had only been observed using culture-independent techniques. Chemical studies of the type strains representing two new families within the order Cytophagales led to the isolation of nine new alkaloid secondary metabolites that can be grouped into four distinct structure classes, including azepinones, aziridines, quinolones, and pyrazinones. Several of these compounds possess antibacterial properties and appear, on structural grounds, to be produced by amino acid-based biosynthetic pathways. Our results demonstrate that relatively simple cultivation techniques can lead to the isolation of new bacterial taxa that are capable of the production of alkaloid secondary metabolites with antibacterial activities. These findings support continued investment in cultivation techniques as a method for natural product discovery.
Assuntos
Alcaloides/biossíntese , Antibacterianos/biossíntese , Organismos Aquáticos/metabolismo , Bacteroidetes/metabolismo , Proteobactérias/metabolismo , Alcaloides/química , Antibacterianos/isolamento & purificação , Organismos Aquáticos/citologia , Organismos Aquáticos/isolamento & purificação , Bacteroidetes/citologia , Bacteroidetes/genética , Dados de Sequência Molecular , Filogenia , Proteobactérias/citologia , Proteobactérias/genética , Análise de Sequência de DNARESUMO
Chemical investigation of a marine actinomycete within the family Streptomycetaceae (our strain CNQ-149) has led to the isolation of the unprecedented alkaloids, actinobenzoquinoline (1) and actinophenanthrolines A-C (2-4). The chemical structures of 1-4 were assigned by interpretation of NMR spectroscopic data, and their absolute configurations were assigned by X-ray analysis. Actinobenzoquinoline possesses a 5-methyloxazolidin-4-one moiety and a dihydrobenzo[h]quinoline core structure, while actinophenanthrolines A-C are composed of hydroxypropanamide-substituted 1,7-phenanthroline core skeletons.
Assuntos
Actinobacteria/química , Alcaloides/isolamento & purificação , Fenantrolinas/isolamento & purificação , Quinolinas/isolamento & purificação , Alcaloides/química , Cristalografia por Raios X , Biologia Marinha , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Conformação Molecular , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Fenantrolinas/química , Quinolinas/químicaRESUMO
The isolation and structure elucidation of a new meroterpenoid, actinoranone (1), produced by a marine bacterium closely related to the genus Streptomyces is reported. Actinoranone is composed of an unprecedented dihydronaphthalenone polyketide linked to a bicyclic diterpenoid. The stereochemistry of 1 was defined by application of the advanced Mosher's method and by interpretation of spectroscopic data. Actinoranone (1) is significantly cytotoxic to HCT-116 human colon cancer cells with an LD50 = 2.0 µg/mL.
Assuntos
Diterpenos/química , Diterpenos/toxicidade , Streptomyces/química , Terpenos/química , Animais , Diterpenos/isolamento & purificação , Diterpenos/farmacologia , Células HCT116 , Humanos , Biologia Marinha , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , EstereoisomerismoAssuntos
Actinomycetales/química , Lactonas/farmacologia , Complexos Multienzimáticos/antagonistas & inibidores , Inibidores de Proteases/farmacologia , Actinomycetales/classificação , Adenocarcinoma/metabolismo , Neoplasias do Colo/metabolismo , Cristalografia por Raios X , Cisteína Endopeptidases , Humanos , Concentração Inibidora 50 , Lactonas/química , Lactonas/isolamento & purificação , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteases/química , Inibidores de Proteases/isolamento & purificação , Complexo de Endopeptidases do Proteassoma , Pirróis , Células Tumorais CultivadasRESUMO
Chemical examination of the secondary metabolites of a marine Saccharomonospora sp., isolated from marine sediments collected at the mouth of the La Jolla Submarine Canyon, yielded the unprecedented alkaloid lodopyridone (1). The low proton-to-carbon ratio of 1 precluded structure elucidation by NMR spectroscopic methods, thus the structure was defined by X-ray crystallography. Lodopyridone is cytotoxic to HCT-116 human colon cancer cells with IC(50) = 3.6 microM.
Assuntos
Actinobacteria/química , Alcaloides/isolamento & purificação , Antineoplásicos/isolamento & purificação , Alcaloides/química , Alcaloides/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Células HCT116 , Humanos , Biologia Marinha , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Conformação Molecular , Estrutura Molecular , Ressonância Magnética Nuclear BiomolecularRESUMO
Two novel spiroaminals, marineosins A and B (1, 2), containing two pyrrole functionalities, were isolated from cultures of a marine sediment-derived actinomycete related to the genus Streptomyces. The marineosins, which appear to be derived from unknown modifications of prodigiosin-like pigment pathways, showed significant inhibition of human colon carcinoma (HCT-116) in an in vitro assay (IC50 = 0.5 microM for marineosin A) and selective activities in diverse cancer cell types.