Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
1.
Appl Environ Microbiol ; 81(11): 3869-79, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25819962

RESUMEN

Antibiotics have either bactericidal or bacteriostatic activity. However, they also induce considerable gene expression in bacteria when used at subinhibitory concentrations (below the MIC). We found that lincomycin, which inhibits protein synthesis by binding to the ribosomes of Gram-positive bacteria, was effective for inducing the expression of genes involved in secondary metabolism in Streptomyces strains when added to medium at subinhibitory concentrations. In Streptomyces coelicolor A3(2), lincomycin at 1/10 of its MIC markedly increased the expression of the pathway-specific regulatory gene actII-ORF4 in the blue-pigmented antibiotic actinorhodin (ACT) biosynthetic gene cluster, which resulted in ACT overproduction. Intriguingly, S. lividans 1326 grown in the presence of lincomycin at a subinhibitory concentration (1/12 or 1/3 of its MIC) produced abundant antibacterial compounds that were not detected in cells grown in lincomycin-free medium. Bioassay and mass spectrometry analysis revealed that some antibacterial compounds were novel congeners of calcium-dependent antibiotics. Our results indicate that lincomycin at subinhibitory concentrations potentiates the production of secondary metabolites in Streptomyces strains and suggest that activating these strains by utilizing the dose-response effects of lincomycin could be used to effectively induce the production of cryptic secondary metabolites. In addition to these findings, we also report that lincomycin used at concentrations for markedly increased ACT production resulted in alteration of the cytoplasmic protein (FoF1 ATP synthase α and ß subunits, etc.) profile and increased intracellular ATP levels. A fundamental mechanism for these unique phenomena is also discussed.


Asunto(s)
Antibacterianos/metabolismo , Lincomicina/metabolismo , Metabolismo Secundario/efectos de los fármacos , Streptomyces/efectos de los fármacos , Streptomyces/metabolismo , Medios de Cultivo/química , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Pigmentos Biológicos/metabolismo , Análisis Espectral
2.
Mar Drugs ; 13(1): 581-96, 2015 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-25603349

RESUMEN

The incorporation pattern of biosynthetic precursors into two structurally unique polyketides, akaeolide and lorneic acid A, was elucidated by feeding experiments with 13C-labeled precursors. In addition, the draft genome sequence of the producer, Streptomyces sp. NPS554, was performed and the biosynthetic gene clusters for these polyketides were identified. The putative gene clusters contain all the polyketide synthase (PKS) domains necessary for assembly of the carbon skeletons. Combined with the 13C-labeling results, gene function prediction enabled us to propose biosynthetic pathways involving unusual carbon-carbon bond formation reactions. Genome analysis also indicated the presence of at least ten orphan type I PKS gene clusters that might be responsible for the production of new polyketides.


Asunto(s)
Derivados del Benceno/metabolismo , Macrólidos/metabolismo , Familia de Multigenes/genética , Sintasas Poliquetidas/genética , Streptomyces/genética , Genoma Bacteriano/genética , Anotación de Secuencia Molecular , Datos de Secuencia Molecular , Estructura Molecular , Sintasas Poliquetidas/metabolismo , Streptomyces/enzimología , Streptomyces/metabolismo
3.
J Oleo Sci ; 73(8): 1083-1090, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39019618

RESUMEN

Growing evidence indicates that the intake of trans fatty acids (TFAs) increases the risk of numerous diseases, such as cardiovascular diseases. Recently, our group found that certain natural sulfur compounds (allyl isothiocyanate [AITC] and diallyl disulfide [DADS]) promote cis to trans isomerization of fatty acid esters during heat treatment. However, little information is available on the fatty acid isomerization with them. In this study, we investigated the effects of oxygen and α-tocopherol (antioxidant) on isomerization of oleic acid (18:1) methyl ester (OA-ME) in the presence of AITC and DADS. Furthermore, the effect of the simultaneous use of AITC and DADS was evaluated. Our results indicate that oxygen enhances the AITC-induced trans isomerization, and DADS was found to promote trans isomerization but inhibit AITC-induced trans isomerization during heating. Both AITC- and DADS-induced trans isomerization were inhibited by α-tocopherol. These results indicate that the trans isomerization of fatty acids induced by sulfur compounds can be controlled by devising a cooking process and the food ingredients used together.


Asunto(s)
Disulfuros , Isotiocianatos , Ácidos Oléicos , alfa-Tocoferol , Isomerismo , alfa-Tocoferol/química , Disulfuros/química , Ácidos Oléicos/química , Isotiocianatos/química , Compuestos Alílicos/química , Oxígeno/química , Antioxidantes/química , Calor , Compuestos de Azufre/química , Culinaria , Ácido Oléico/química , Ácidos Grasos trans/química , Ésteres/química , Estereoisomerismo , Cisteína/análogos & derivados
4.
J Oleo Sci ; 72(9): 881-887, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37648465

RESUMEN

The effects of allyl isothiocyanate (AITC) and diallyl disulfide (DADS), widely found in edible vegetables, on thermal isomerization of unsaturated fatty acid esters (oleic acid methyl ester [OA-ME], linoleic acid methyl ester [LA-ME], and eicosapentaenoic acid ethyl ester [EPA-EE]) were investigated. Although heating with AITC and DADS significantly promoted cis to trans isomerization of all fatty acid esters, the isomerization trends varied greatly depending on the type of fatty acid. Specifically, AITC promoted thermal isomerization of OA-ME and LA-ME more efficiently than DADS; however, an opposite result was obtained for EPA-EE. For example, when OA-ME was heated at 180°C for 1 h with 1.0 equivalent of AITC and DADS, its trans isomer ratios reached 29.0 ± 7.1 and 7.6 ± 0.6%, respectively, and when EPA-EE was heated under the same conditions, its trans isomer ratios reached 4.2 ± 0.4 and 8.6 ± 0.2%, respectively. These results indicate that isothiocyanates and polysulfides would promote the formation of trans fatty acids in food processing under heating conditions.


Asunto(s)
Calor , Compuestos de Azufre , Isomerismo , Isotiocianatos , Ácidos Grasos , Ésteres
5.
iScience ; 26(12): 108411, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-38047069

RESUMEN

Very-long-chain polyunsaturated fatty acids (VLCPUFAs; C24-38) constitute a unique class of PUFA that have important biological roles, but the lack of a suitable dietary source has limited research in this field. We produced an n-3 C24-28-rich VLCPUFA-oil concentrated from fish oil to study its bioavailability and physiological functions in C57BL/6J mice. The serum and retinal C24:5 levels increased significantly compared to control after a single-dose gavage, and VLCPUFAs were incorporated into the liver, brain, and eyes after 8-week supplementation. Dietary VLCPUFAs resulted in favorable cardiometabolic changes, and improved electroretinography responses and visual performance. VLCPUFA supplementation changed the expression of genes involved in PPAR signaling pathways. Further in vitro studies demonstrated that the VLCPUFA-oil and chemically synthesized C24:5 are potent agonists for PPARs. The multiple potential beneficial effects of fish oil-derived VLCPUFAs on cardiometabolic risk and eye health in mice support future efforts to develop VLCPUFA-oil into a supplemental therapy.

6.
J Nat Prod ; 75(11): 1974-82, 2012 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-23102410

RESUMEN

Nine new 26-membered macrolides of the oligomycin subfamily, neomaclafungins A-I, were isolated from the fermentation broth of Actinoalloteichus sp. NPS702, which was isolated from marine sediment collected from Usa Bay, Kochi Prefecture, Japan. Their structures were identified through mass spectrometry and NMR experiments. They belong to the oligomycin class and have several distinct features including the presence of alkane or alkanol branches. Neomaclafungins A-I exhibited significant antifungal activity in vitro against Trichophyton mentagrophytes (ATCC 9533), showing MIC values between 1 and 3 µg/mL.


Asunto(s)
Antifúngicos/aislamiento & purificación , Antifúngicos/farmacología , Oligomicinas/aislamiento & purificación , Oligomicinas/farmacología , Antifúngicos/química , Japón , Biología Marina , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Oligomicinas/química , Streptomyces/química , Trichophyton/efectos de los fármacos
7.
Bioorg Med Chem Lett ; 21(23): 7099-101, 2011 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-22001031

RESUMEN

New anthramycin-type analogues, designated usabamycin A-C (1, 2 and 3), have been isolated from cultures of Streptomyces sp. NPS853, a bacterium found in marine sediments. The structures of the new compounds were established on the basis of extensive spectroscopic analyses including 1D- and 2D-NMR ((1)H-(1)H COSY, HSQC, and HMBC) experiments. The usabamycins show weak inhibition of HeLa cell growth and selective inhibition of serotonin (5-hydroxytrypamine) 5-HT(2B) uptake.


Asunto(s)
Actinobacteria/química , Antramicina/análogos & derivados , Antramicina/química , Antramicina/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Antineoplásicos/farmacología , Proliferación Celular/efectos de los fármacos , Células HeLa , Humanos , Concentración 50 Inhibidora , Espectroscopía de Resonancia Magnética , Estructura Molecular , Antagonistas de la Serotonina/síntesis química , Antagonistas de la Serotonina/química , Antagonistas de la Serotonina/farmacología
8.
Bioorg Med Chem Lett ; 20(3): 1070-4, 2010 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-20036535

RESUMEN

Two cyclic diarylheptanoids, acerogenins A (1) and B (2) have been isolated from the bark of Acer nikoense as inhibitors of Na(+)-glucose cotransporter (SGLT). Acerogenins A (1) and B (2) inhibited both isoforms, SGLT1 and SGLT2. Structure-activity relationship of acerogenin derivatives on inhibitory activity of SGLT as well as conformational analysis of 1 and 2 on the basis of J-resolved HMBC spectra and X-ray analysis were discussed.


Asunto(s)
Acer , Diarilheptanoides/química , Extractos Vegetales/química , Transportador 1 de Sodio-Glucosa/antagonistas & inhibidores , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Cristalografía por Rayos X , Diarilheptanoides/aislamiento & purificación , Diarilheptanoides/farmacología , Corteza de la Planta , Extractos Vegetales/aislamiento & purificación , Extractos Vegetales/farmacología , Transportador 1 de Sodio-Glucosa/metabolismo , Transportador 2 de Sodio-Glucosa/metabolismo
9.
Bioorg Med Chem ; 18(6): 2152-2158, 2010 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-20189404

RESUMEN

Three new picraline-type alkaloids, alstiphyllanines E-G (1-3) and a new ajmaline-type alkaloid, alstiphyllanine H (4) were isolated from the leaves of Alstonia macrophylla together with 16 related alkaloids (5-20). Structures and stereochemistry of 1-4 were fully elucidated and characterized by 2D NMR analysis. Alstiphyllanines E and F (1 and 2) showed moderate Na(+)-glucose cotransporter (SGLT1 and SGLT2) inhibitory activity. A series of a hydroxy substituted derivatives 21-28 at C-17 of the picraline-type alkaloids have been derived as having potent SGLT inhibitory activity. 10-Methoxy-N(1)-methylburnamine-17-O-veratrate (6) exhibited potent inhibitory activity, suggesting that the presence of an ester side chain at C-17 may be important to show SGLT inhibitory activity. Structure activity relationship of alstiphyllanines on inhibitory activity of SGLT was discussed.


Asunto(s)
Alstonia/química , Alcaloides Indólicos/farmacología , Hojas de la Planta/química , Transportador 1 de Sodio-Glucosa/antagonistas & inhibidores , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Animales , Células COS , Células Cultivadas , Chlorocebus aethiops , Alcaloides Indólicos/química , Alcaloides Indólicos/aislamiento & purificación , Conformación Molecular , Estereoisomerismo , Relación Estructura-Actividad
10.
J Nat Prod ; 73(4): 763-7, 2010 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-20192242

RESUMEN

Gneyulins A (1) and B (2), two new stilbene trimers consisting of oxyresveratrol constituent units, and noidesols A (3) and B (4), two new dihydroflavonol-C-glucosides, were isolated from the bark of Gnetum gnemonoides. The structures and configurations of 1-4 were elucidated on the basis of 2D NMR correlations and X-ray analysis. Gneyulins A (1) and B (2) showed inhibition of Na(+)-glucose transporters (SGLT-1 and SGLT-2).


Asunto(s)
Flavonoles/aislamiento & purificación , Glucósidos/aislamiento & purificación , Gnetum/química , Estilbenos/aislamiento & purificación , Cristalografía por Rayos X , Flavonoles/química , Flavonoles/farmacología , Glucósidos/química , Glucósidos/farmacología , Malasia , Conformación Molecular , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Corteza de la Planta/química , Transportador 1 de Sodio-Glucosa/antagonistas & inhibidores , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Estilbenos/química , Estilbenos/farmacología
11.
J Org Chem ; 74(15): 5502-9, 2009 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-19572603

RESUMEN

Six antitumor antibiotics of a new structure class, indoxamycins A-F (1-6), were isolated from a saline culture group of marine-derived actinomyces whose strains showed approximately 96% sequence homology of 16S rDNA with the family streptomycetaceae. The structures of these indoxamycins, which are unusual polyketides composed of six consecutive chiral centers, were assigned by combined spectral and chemical methods. In feeding experiments using a stable isotope label, indoxamycin A was assembled from propionate units initially forming the "aglycon" pentamethyl indeno furan. The discovery of these unprecedented compounds from marine-derived actinomycetes, a low gene homology genus, offers a significant opportunity for drug discovery.


Asunto(s)
Actinobacteria/química , Antibióticos Antineoplásicos/farmacología , Compuestos Heterocíclicos con 3 Anillos/farmacología , Propionatos/farmacología , Antibióticos Antineoplásicos/química , Antibióticos Antineoplásicos/aislamiento & purificación , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Descubrimiento de Drogas , Ensayos de Selección de Medicamentos Antitumorales , Compuestos Heterocíclicos con 3 Anillos/química , Compuestos Heterocíclicos con 3 Anillos/aislamiento & purificación , Humanos , Biología Marina , Conformación Molecular , Tamaño de la Partícula , Propionatos/química , Propionatos/aislamiento & purificación , Estereoisomerismo
12.
J Nat Prod ; 72(11): 2046-8, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19856955

RESUMEN

A marine-derived actinomyces strain (NPS554) isolated from a marine sediment sample collected from Miyazaki Harbor, Japan, at a depth of 38 m yielded two trialkyl-substituted aromatic acids, lorneic acid A (1) and lorneic acid B (2). The structures of the lorneic acids, which were elucidated by spectroscopic analysis, differed only in the side-chain, which contained either a conjugated double bond or a benzylic alcohol. Their structural differences affected inhibition activities against phosphodiesterase 5.


Asunto(s)
Derivados del Benceno/aislamiento & purificación , Inhibidores de Fosfodiesterasa 5 , Actinobacteria/química , Derivados del Benceno/química , Derivados del Benceno/farmacología , Plaquetas/enzimología , Humanos , Japón , Biología Marina , Estructura Molecular
13.
Org Lett ; 15(22): 5678-81, 2013 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-24134782

RESUMEN

Akaeolide, a novel polycyclic polyketide, was isolated from the culture extract of a marine-derived actinomycete belonging to the genus Streptomyces. The planar structure of the new compound was elucidated by spectroscopic analysis including NMR and MS, and the absolute configuration was determined by X-ray crystallographic analysis of its chlorinated derivative. Akaeolide possesses a 15-membered carbocyclic framework, apparently derived from the malonate pathway, with a tetrahydrofuran ring and a ß-keto-δ-lactone unit.


Asunto(s)
Furanos/química , Macrólidos/química , Policétidos/química , Streptomyces/química , Cristalografía por Rayos X , Macrólidos/aislamiento & purificación , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Policétidos/aislamiento & purificación
15.
J Food Sci ; 74(4): H116-20, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19490329

RESUMEN

Antarctic krill (Euphausia superba) obtained from the huge biomass in Antarctic waters is an important food product in Japan. Antarctic krill peptide powder (AKPP) prepared from the tail meat by enzymatic hydrolysis significantly decreased the systolic blood pressure in spontaneously hypertensive rats by a single oral administration (1, 10, or 100 mg). Presumably, the effect of AKPP was through inhibition of the conversion of angiotensin, which mediates blood pressure elevation, from its inactive propeptide to the mature angiotensin. Two potent angiotensin I-converting enzyme (ACE) inhibitory peptides were isolated from AKPP by high-performance liquid chromatography (HPLC) and identified as Val-Trp (IC(50)= 2.75 microg/mL; 12.9 microM) and Leu-Lys-Tyr (IC(50)= 4.26 microg/mL; 10.1 microM). Val-Trp and Leu-Lys-Tyr comprised 0.025%+/- 0.0023% (w/w) and 0.018%+/- 0.0023% (w/w) of AKPP, respectively, as measured by electrospray ionization mass spectrometry (ESI-MS). The contributions of Val-Trp and Leu-Lys-Tyr to the ACE inhibitor activity of AKPP were 17.7%+/- 1.60% and 8.04%+/- 1.03%, respectively, suggesting that these 2 peptides constitute a substantial portion of the overall ACE inhibitor potential of AKPP.


Asunto(s)
Antihipertensivos/aislamiento & purificación , Euphausiacea/química , Péptidos/aislamiento & purificación , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Animales , Antihipertensivos/farmacología , Cromatografía Líquida de Alta Presión , Dipéptidos/administración & dosificación , Dipéptidos/aislamiento & purificación , Dipéptidos/farmacología , Hidrólisis , Hipertensión/tratamiento farmacológico , Masculino , Oligopéptidos/administración & dosificación , Oligopéptidos/aislamiento & purificación , Oligopéptidos/farmacología , Péptidos/farmacología , Ratas , Ratas Endogámicas SHR , Espectrometría de Masa por Ionización de Electrospray , Cola (estructura animal)
16.
Bioorg Med Chem ; 15(10): 3445-9, 2007 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-17374486

RESUMEN

The methanol extract of Sophora flavescens, which is used in traditional Chinese medicine (sophorae radix), showed potent Na(+)-glucose cotransporter (SGLT) inhibitory activity. Our search for active components identified many well-known flavonoid antioxidants: kurarinone, sophoraflavanone G, kushenol K, and kushenol N.


Asunto(s)
Flavonoides/aislamiento & purificación , Flavonoides/farmacología , Transportador 1 de Sodio-Glucosa/antagonistas & inhibidores , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Sophora/química , Animales , Células COS , Chlorocebus aethiops , Humanos , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Raíces de Plantas/química , Plásmidos/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transportador 1 de Sodio-Glucosa/genética , Transportador 2 de Sodio-Glucosa/genética , Espectrometría de Masa por Ionización de Electrospray
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA