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1.
J Nat Prod ; 84(1): 46-55, 2021 01 22.
Artículo en Inglés | MEDLINE | ID: mdl-33342211

RESUMEN

Naphthoquinones isolated from Quambalaria cyanescens (quambalarines) are natural pigments possessing significant cytotoxic and antimicrobial properties. Determining the structure of naphthoquinone compounds is important for the understanding of their biological activities and the informed synthesis of related analogues. Identifying quambalarines is challenging, because they contain a hydroxylated naphthoquinone scaffold and have limited solubility. Here, we report a detailed structural study of quambalarine derivatives, which form strong intramolecular hydrogen bonds (IMHBs) that enable the formation of several tautomers; these tautomers may complicate structural investigation due to their fast interconversion. To investigate tautomeric equilibria and identify new quambalarines, we complemented the experimental NMR spectroscopy data with density functional theory (DFT) calculations.


Asunto(s)
Antiinfecciosos/farmacología , Antineoplásicos/farmacología , Basidiomycota/química , Naftoquinonas/farmacología , Antiinfecciosos/química , Antiinfecciosos/aislamiento & purificación , Antineoplásicos/química , Antineoplásicos/aislamiento & purificación , Enlace de Hidrógeno , Imagen por Resonancia Magnética , Espectroscopía de Resonancia Magnética , Estructura Molecular , Naftoquinonas/química , Naftoquinonas/aislamiento & purificación
2.
Mol Phylogenet Evol ; 123: 73-87, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29481949

RESUMEN

The ergot, genus Claviceps, comprises approximately 60 species of specialised ovarial grass parasites famous for the production of food toxins and pharmaceutics. Although the ergot has been known for centuries, its evolution have not been resolved yet. Our approach combining multilocus phylogeny, molecular dating and the study of ecological, morphological and metabolic features shows that Claviceps originated in South America in the Palaeocene on a common ancestor of BEP (subfamilies Bambusoideae, Ehrhartoideae, Pooideae) and PACMAD (subfamilies Panicoideae, Aristidoideae, Chloridoideae, Micrairoideae, Arundinoideae, Danthonioideae) grasses. Four clades described here as sections diverged during the Paleocene and Eocene. Since Claviceps are parasitic fungi with a close relationship with their host plants, their evolution is influenced by interactions with the new hosts, either by the spread to a new continent or the radiation of the host plants. Three of the sections possess very narrow host ranges and biogeographical distributions and have relatively low toxicity. On the contrary, the section Claviceps, comprising the rye ergot, C. purpurea, is unique in all aspects. Fungi in this section of North American origin have spread all over the world and infect grasses in all subfamilies as well as sedges, and it is the only section synthesising toxic ergopeptines and secalonic acids. The evolutionary success of the Claviceps section members can be explained by high toxin presence, serving as feeding deterrents and playing a role in their protective mutualism with host plants. Closely related taxa Neoclaviceps monostipa and Cepsiclava phalaridis were combined into the genus Aciculosporium.


Asunto(s)
Claviceps/clasificación , Filogenia , Teorema de Bayes , Alcaloides de Claviceps/biosíntesis , Alcaloides de Claviceps/química , Sitios Genéticos , Geografía , Especificidad del Huésped , Metabolismo Secundario , América del Sur , Factores de Tiempo
3.
J Nat Prod ; 79(9): 2304-14, 2016 09 23.
Artículo en Inglés | MEDLINE | ID: mdl-27571379

RESUMEN

Quambalarine B (QB) is a secondary metabolite produced by the basidiomycete Quambalaria cyanescens with potential anticancer activity. Here we report that QB at low micromolar concentration inhibits proliferation of several model leukemic cell lines (Jurkat, NALM6, and REH), whereas higher concentrations induce cell death. By contrast, the effect of QB on primary leukocytes (peripheral blood mononuclear cells) is significantly milder with lower toxicity and cytostatic activity. Moreover, QB inhibited expression of the C-MYC oncoprotein and mRNA expression of its target genes, LDHA, PKM2, and GLS. Finally, QB blocked the phosphorylation of P70S6K, a downstream effector kinase in mTOR signaling that regulates translation of C-MYC. This observation could explain the molecular mechanism behind the antiproliferative and cytotoxic effects of QB on leukemic cells. Altogether, our results establish QB as a promising molecule in anticancer treatment.


Asunto(s)
Antineoplásicos/química , Antineoplásicos/farmacología , Basidiomycota/química , Naftoquinonas/química , Naftoquinonas/farmacología , Antineoplásicos/sangre , Antineoplásicos/aislamiento & purificación , Proliferación Celular/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Células Jurkat/efectos de los fármacos , Leucocitos Mononucleares/efectos de los fármacos , Estructura Molecular , Naftoquinonas/sangre , Naftoquinonas/síntesis química , Naftoquinonas/aislamiento & purificación , Fosforilación , Proteínas Quinasas S6 Ribosómicas 70-kDa , Transducción de Señal/fisiología , Serina-Treonina Quinasas TOR
4.
Fungal Biol ; 126(11-12): 752-763, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36517143

RESUMEN

Ergot, the genus Claviceps comprises several deeply diverged lineages, recently classified as sections. Among them, the section Pusillae, is the most speciose, with a centre of distribution in Africa but occurring worldwide, often as a consequence of its invasive potential. This section includes the most severe plant pathogens such as Claviceps africana and C. gigantea, responsible for toxicoses and a significant reduction in the seed yields of Sorghum and Zea. In this study we surveyed ergot diversity in South Africa, focusing on grasses native to this region, but known for their high potential of invasiveness. The revision based on molecular and phenotypic markers revealed 16 species, with a high proportion of undescribed diversity, confirming Africa as a hot spot for this section. Five new species, Claviceps tulasnei, Claviceps eulaliae, Claviceps hypertheliae, Claviceps fredericksoniae and Claviceps arundinellae were described from Setaria, Eulalia, Hyperthelia, Miscanthus and Arundinella respectively. Claviceps texensis infecting Cenchrus, previously only identified from the same host in Texas, USA, was confirmed to be present in Africa, which is assumed to be its primary area of distribution. In addition, the host grass genus Anthephora is newly reported as a host of Claviceps digitariae. The most of the taxa were negligible concerning alkaloid production, with the exception of C. fredericksoniae, which is a sister of potent alkaloid producer C. africana, and produces mainly DH-ergosine, together with traces of DH-ergocornine. The host/parasite associations within Pusillae section is very narrow, suggesting that co-speciation is the major speciation driver in this group. Host grasses of the described species are already recognised invasive species and their ovarial parasites need to be monitored. This is highlighted by the fact that all Pusillae produced air-borne secondary conidia, which is autapomorphy of this section and considered to be important for their invasive abilities.


Asunto(s)
Claviceps , Alcaloides de Claviceps , Humanos , Claviceps/genética , Poaceae , Sudáfrica , Pueblo Africano
5.
Eur J Med Chem ; 208: 112754, 2020 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-32883638

RESUMEN

The biological effects of flavonoids on mammal cells are diverse, ranging from scavenging free radicals and anti-cancer activity to anti-influenza activity. Despite appreciable effort to understand the anti-influenza activity of flavonoids, there is no clear consensus about their precise mode-of-action at a cellular level. Here, we report the development and validation of a screening assay based on AlphaScreen technology and illustrate its application for determination of the inhibitory potency of a large set of polyols against PA N-terminal domain (PA-Nter) of influenza RNA-dependent RNA polymerase featuring endonuclease activity. The most potent inhibitors we identified were luteolin with an IC50 of 72 ± 2 nM and its 8-C-glucoside orientin with an IC50 of 43 ± 2 nM. Submicromolar inhibitors were also evaluated by an in vitro endonuclease activity assay using single-stranded DNA, and the results were in full agreement with data from the competitive AlphaScreen assay. Using X-ray crystallography, we analyzed structures of the PA-Nter in complex with luteolin at 2.0 Å resolution and quambalarine B at 2.5 Å resolution, which clearly revealed the binding pose of these polyols coordinated to two manganese ions in the endonuclease active site. Using two distinct assays along with the structural work, we have presumably identified and characterized the molecular mode-of-action of flavonoids in influenza-infected cells.


Asunto(s)
Antivirales/química , Endonucleasas/antagonistas & inhibidores , Inhibidores Enzimáticos/química , Flavonoides/química , Virus de la Influenza A/enzimología , Proteínas Virales/antagonistas & inhibidores , Antivirales/metabolismo , Cristalografía por Rayos X , Evaluación Preclínica de Medicamentos , Endonucleasas/química , Endonucleasas/metabolismo , Pruebas de Enzimas/métodos , Inhibidores Enzimáticos/metabolismo , Flavonoides/metabolismo , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Unión Proteica , Dominios Proteicos , ARN Polimerasa Dependiente del ARN/antagonistas & inhibidores , ARN Polimerasa Dependiente del ARN/química , ARN Polimerasa Dependiente del ARN/metabolismo , Relación Estructura-Actividad , Proteínas Virales/química , Proteínas Virales/metabolismo
6.
Electrophoresis ; 30(16): 2890-6, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19691053

RESUMEN

The enantioseparation of carboxylic acids, including amino acid dansyl-derivatives, 2-arylpropionic acids and 2-aryloxypropionic acids, was tested by CEC on a porous silica sol-gel monolithic column that was prepared by polycondensation of tetramethoxysilane in acidic conditions and post-gelation heat treatment (120 degrees C for 3 h) in the presence of urea, and successively, by anchoring to the silica (+)-1-allyl-(5R,8S,10R)-terguride as the chiral selector. The bimodal structure of the sorbent showed through pores with a median value of 1.39 mum and a mesopore size distribution ranging between 6 and 12 nm (average pore size of 9.9 nm). To attain optimum separation conditions, the influence of the pH and the concentration of the buffer solution in the mobile phase on resolution were investigated. The monolithic column showed: (i) for the compounds studied resolution values two or three times higher in comparison with previously developed separation systems where the same chiral selector was used. For example, on the monolithic column Dns-serine enantiomers were much better separated (8 min with a selectivity factor of 1.34) than by HPLC (20 min, alpha=1.17); (ii) high chemical and mechanical stability as demonstrated by the use of such column for hundreds of analysis along about 1 year without significant variations of the resolution and the retention parameters.


Asunto(s)
Electrocromatografía Capilar/métodos , Ácidos Carboxílicos/aislamiento & purificación , Alcaloides de Claviceps/química , Dióxido de Silicio/química , Aminoácidos/química , Aminoácidos/aislamiento & purificación , Ácidos Carboxílicos/química , Compuestos de Dansilo/química , Compuestos de Dansilo/aislamiento & purificación , Estabilidad de Medicamentos , Concentración de Iones de Hidrógeno , Microscopía Electrónica de Rastreo , Porosidad , Reproducibilidad de los Resultados , Estereoisomerismo , Temperatura
7.
Toxins (Basel) ; 11(8)2019 07 25.
Artículo en Inglés | MEDLINE | ID: mdl-31349616

RESUMEN

Ergot, fungal genus Claviceps, are worldwide distributed grass pathogens known for their production of toxic ergot alkaloids (EAs) and the great agricultural impact they have on both cereal crop and farm animal production. EAs are traditionally considered as the only factor responsible for ergot toxicity. Using broad sampling covering 13 ergot species infecting wild or agricultural grasses (including cereals) across Europe, USA, New Zealand, and South Africa we showed that the content of ergochrome pigments were comparable to the content of EAs in sclerotia. While secalonic acids A-C (SAs), the main ergot ergochromes (ECs), are well known toxins, our study is the first to address the question about their contribution to overall ergot toxicity. Based on our and published data, the importance of SAs in acute intoxication seems to be negligible, but the effect of chronic exposure needs to be evaluated. Nevertheless, they have biological activities at doses corresponding to quantities found in natural conditions. Our study highlights the need for a re-evaluation of ergot toxicity mechanisms and further studies of SAs' impact on livestock production and food safety.


Asunto(s)
Claviceps/química , Alcaloides de Claviceps/toxicidad , Micotoxinas/toxicidad , Xantenos/toxicidad , Apoptosis/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Alcaloides de Claviceps/análisis , Células HeLa , Humanos , Células Jurkat , Mitocondrias/efectos de los fármacos , Micotoxinas/análisis , Micotoxinas/farmacología , Xantenos/análisis
8.
J Pharmacol Exp Ther ; 324(3): 1136-45, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18096760

RESUMEN

Cardiac-valve regurgitation observed in Parkinson patients treated with the ergoline dopamine receptor agonist 8beta-methylthiomethyl-6-propylergoline (pergolide) has been associated with the agonist efficacy of the drug at 5-hydroxytryptamine(2B) (5-HT(2B)) receptors. 5-HT(2A) receptors may also play a role in pergolide-induced cardiac-valve regurgitation. We studied the pharmacological profile of pergolide and eight derivatives in porcine vascular rings endowed with 5-HT(2B) and 5-HT(2A) receptors to detect the molecular fragment of the pergolide molecule that may be responsible for agonism at these receptors. Pergolide derivatives showed a different substitution pattern at N(6), and the side chain at C(8) was modified by replacement of the sulfur against an oxygen atom. We demonstrate that the potent agonism of pergolide both at 5-HT(2B) and 5-HT(2A) receptors is retained when the N(6) propyl substituent is replaced by ethyl. However, agonism can be converted into antagonism if N(6) propyl is replaced by methyl. The N(6)-unsubstituted derivative was a low efficacy 5-HT(2B) receptor partial agonist and a 5-HT(2A) receptor antagonist. This pharmacological pattern was also applicable for pergolide congeners with an oxygen in the side chain at C(8). 6-Methylpergolide retained agonist efficacy and potency compared with pergolide at human (h) D(2LONG(L)) and hD(2SHORT(S)) receptors as determined by guanosine 5'-O-(3-[(35)S]thio)triphosphate binding. Based on the ability of pergolide to produce potent agonism at 5-HT(2B) receptors and the failure of 6-methylpergolide to act as an agonist but as a potent antagonist, we conclude that the N(6) propyl substituent of pergolide is crucial for 5-HT(2B) receptor agonism and thus a determinant of valvular regurgitation.


Asunto(s)
Pergolida/química , Pergolida/farmacología , Agonistas del Receptor de Serotonina 5-HT2 , Agonistas de Receptores de Serotonina/química , Agonistas de Receptores de Serotonina/farmacología , Animales , Relación Dosis-Respuesta a Droga , Técnicas In Vitro , Estructura Molecular , Arteria Pulmonar/efectos de los fármacos , Arteria Pulmonar/fisiología , Receptor de Serotonina 5-HT2A/fisiología , Receptor de Serotonina 5-HT2B/fisiología , Porcinos , Vasodilatación/efectos de los fármacos , Vasodilatación/fisiología
9.
Immunol Lett ; 116(1): 79-85, 2008 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-18160138

RESUMEN

Peptides eluted from peripheral blood cells of HLA-B*2705 healthy donor were analyzed by LC MALDI MS/MS and LC ESI FTMS techniques. The sequences of 92 peptide ligands identified from one healthy blood donor by LC MALDI-TOF MS/MS were compared with those previously published from in vitro long-term cell cultures available in SYFPEITHI database and splenocytes. It was found that 18 sequences confirmed within 1ppm mass error by LC ESI FTMS were already described and 3 of them matched with those previously reported from HLA-B*2705 splenocytes. Another 38 sequences validated within the same mass error were not found in SYFPEITHI database and are identified here for the first time. Finally, 36 sequences (5 sequences already published in SYFPEITHI database) were evaluated by LC MALDI-TOF MS/MS but no matches in the list of monoisotopic masses obtained from LC ESI FTMS were found.


Asunto(s)
Antígeno HLA-B27/análisis , Mapeo Peptídico , Péptidos/análisis , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Adulto , Oxidorreductasas de Alcohol , Autoinmunidad/genética , Células Sanguíneas/inmunología , Células Sanguíneas/metabolismo , Bases de Datos de Proteínas , Endopeptidasas/metabolismo , Subunidades alfa de la Proteína de Unión al GTP Gs/sangre , Subunidades alfa de la Proteína de Unión al GTP Gs/genética , Subunidades alfa de la Proteína de Unión al GTP Gs/inmunología , Predisposición Genética a la Enfermedad , Antígeno HLA-B27/inmunología , Antígeno HLA-B27/aislamiento & purificación , Proteínas del Choque Térmico HSC70/sangre , Proteínas del Choque Térmico HSC70/genética , Proteínas del Choque Térmico HSC70/inmunología , Histonas/genética , Histonas/metabolismo , Humanos , Masculino , Péptidos/inmunología , Péptidos/aislamiento & purificación , Dominios y Motivos de Interacción de Proteínas , Alineación de Secuencia , Programas Informáticos , Espondilitis Anquilosante/genética , Espondilitis Anquilosante/metabolismo
10.
Naunyn Schmiedebergs Arch Pharmacol ; 376(5): 321-30, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18066532

RESUMEN

Ergot alkaloids act as (partial) agonists or antagonists at serotonergic, dopaminergic and alpha-adrenergic receptors. In contrast to their affinity at serotonergic (5-HT) and dopaminergic receptor subtypes, only limited information is available concerning their interaction with alpha-adrenoceptor subtypes. This especially holds true for native alpha-adrenoceptors. Therefore, we studied the pharmacological profile of 25 ergolines at alpha(1A)-, alpha(1B)- and alpha(1D)-adrenoceptors in vascular rings or strips of rat and guinea pig endowed with these receptors. Contractile responses were studied by measurement of isometric tension changes in rat tail artery (alpha(1A), alpha(1B)), guinea pig spleen (alpha(1B)) and rat thoracic aorta (alpha(1D)). The anti-migraine drugs ergotamine and dihydroergotamine, the anti-parkinsonian drug lisuride and the anti-hyperprolactinemic drug terguride behaved as antagonists or low-efficacy partial agonists at all three alpha(1)-adrenoceptor subtypes with nanomolar receptor affinity. Derivatives of these drugs showed lower affinity at alpha(1)-adrenoceptors than the parent compounds. Each individual ergoline derivative tested showed low discriminatory capability at the subtypes, alpha(1A), alpha(1B), alpha(1D). A low discriminatory power between the subtypes (alpha(1A), alpha(1B), alpha(1D)) seems to be a class effect of the ergolines. The nanomolar affinities of ergotamine, dihydroergotamine and lisuride for alpha(1)-adrenoceptors may affect their effectiveness as anti-migraine and anti-parkinsonian drugs, respectively.


Asunto(s)
Ergolinas/farmacología , Receptores Adrenérgicos alfa 1/efectos de los fármacos , Animales , Aorta Torácica/efectos de los fármacos , Aorta Torácica/metabolismo , Arterias/efectos de los fármacos , Arterias/metabolismo , Relación Dosis-Respuesta a Droga , Ergolinas/administración & dosificación , Cobayas , Contracción Isométrica/efectos de los fármacos , Masculino , Ratas , Ratas Wistar , Receptores Adrenérgicos alfa 1/metabolismo , Bazo/efectos de los fármacos , Bazo/metabolismo , Relación Estructura-Actividad
11.
Artículo en Inglés | MEDLINE | ID: mdl-18774762

RESUMEN

The UPLC method with diode array UV detection was developed for qualitative determination of ergocristine and ergocristam including degradation products. The mechanism of the ergocristam disruptive reaction was described based on MS/MS characterization of ammonolytic product, N-(d-lysergyl)-l-valinamide (A1) and two methanolytic products, methyl ester of N-(d-lysergyl)-l-valine (M2), and N-[N-(d-lysergyl)-l-valyl]-l-phenylalanyl-d-prolyl methyl ester (M1). The influence of extraction conditions on epimerization and degradation of ergocristine and ergocristam was tested and conditions for reproducible decomposition of ergocristam were found. The presented method could potentially be applied for ergot alkaloids determination in sclerotia, fermentation broth, mycelium, and possibly contaminated food products, i.e. corn, flour, bread, etc., and feeding stuffs containing ungrounded cereals.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Ergolinas/análisis , Alcaloides de Claviceps/análisis , Contaminación de Alimentos/análisis , Espectrometría de Masas en Tándem/métodos , Ergolinas/química , Ergolinas/aislamiento & purificación , Alcaloides de Claviceps/química , Alcaloides de Claviceps/aislamiento & purificación
12.
J Nat Prod ; 71(6): 1085-8, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18461998

RESUMEN

Claviceps purpurea, C. grohii, C. zizaniae, C. cyperi, and C. nigricans are closely related ergot fungi and form a monophyletic clade inside the genus Claviceps. Analysis of alkaloid content in C. nigricans sclerotia using UPLC detected ergocristine (1), ergosine (2), alpha-ergocryptine (3), and ergocristam (4). Alkaloids 1, 3, and 4 were found in the sclerotia of C. grohii. The content of 4 in the mixture of alkaloids from C. nigricans and C. grohii (over 8% and over 20%, respectively) was unusually high. Submerged shaken cultures of C. nigricans produced no alkaloids, whereas C. grohii culture formed small amounts (15 mg L (-1)) of extracellular clavines and 1. In the previously used HPLC method the ergocristam degradation product could have been obscured by the ergosine peak. Therefore sclerotia of a C. purpurea habitat-specific population G2 with the dominant production of 1 and 2 have been reanalyzed, but no 4 was detected. The phylogeny of the C. purpurea-related species group is discussed with regard to alkaloid-specific nonribosomal peptide synthetase duplication leading to the production of two main ergopeptines instead of a single product.


Asunto(s)
Alcaloides/aislamiento & purificación , Claviceps/química , Alcaloides/química , Alcaloides/clasificación , Cromatografía Líquida de Alta Presión , Claviceps/genética , Claviceps/crecimiento & desarrollo , República Checa , ADN/análisis , Estructura Molecular , Péptido Sintasas/metabolismo
13.
J Chromatogr A ; 1139(2): 214-20, 2007 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-17125778

RESUMEN

A new separation and quantification method using ultra-performance liquid chromatography (UPLC) with UV detection was developed for detection of lincomycin traces in fermentation broth of different Streptomyces spp. A similar high-performance liquid chromatography (HPLC) protocol was simultaneously developed for comparison purposes. Both methods were validated and showed a linear range of detector response for quantification of lincomycin in concentration from 3.125 to 1000.0 microgml(-1) with correlation coefficient 0.999 and recoveries ranging from 81.5 to 89.85% with precision < or =5%. Compared with the HPLC, the UPLC method offered high sample throughput and about 10 times lower consumption of solvents. The developed assays were used for determination of lincomycin production in genetically manipulated production strain Streptomyces lincolnensis and for determination of lincomycin production after heterologous expression of lincomycin biosynthetic gene cluster in non-producing strain Streptomyces coelicolor.


Asunto(s)
Cromatografía Liquida/métodos , Lincomicina/análisis , Streptomyces/metabolismo , Cromatografía Líquida de Alta Presión/métodos , Fermentación , Organismos Modificados Genéticamente/metabolismo , Sensibilidad y Especificidad , Espectrofotometría Ultravioleta/métodos , Streptomyces/genética
14.
Oncotarget ; 8(61): 103137-103153, 2017 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-29262552

RESUMEN

Abnormalities in cancer metabolism represent potential targets for cancer therapy. We have recently identified a natural compound Quambalarine B (QB), which inhibits proliferation of several leukemic cell lines followed by cell death. We have predicted ubiquinone binding sites of mitochondrial respiratory complexes as potential molecular targets of QB in leukemia cells. Hence, we tracked the effect of QB on leukemia metabolism by applying several omics and biochemical techniques. We have confirmed the inhibition of respiratory complexes by QB and found an increase in the intracellular AMP levels together with respiratory substrates. Inhibition of mitochondrial respiration by QB triggered reprogramming of leukemic cell metabolism involving disproportions in glycolytic flux, inhibition of proteins O-glycosylation, stimulation of glycine synthesis pathway, and pyruvate kinase activity, followed by an increase in pyruvate and a decrease in lactate levels. Inhibition of mitochondrial complex I by QB suppressed folate metabolism as determined by a decrease in formate production. We have also observed an increase in cellular levels of several amino acids except for aspartate, indicating the dependence of Jurkat (T-ALL) cells on aspartate synthesis. These results indicate blockade of mitochondrial complex I and II activity by QB and reduction in aspartate and folate metabolism as therapeutic targets in T-ALL cells. Anti-cancer activity of QB was also confirmed during in vivo studies, suggesting the therapeutic potential of this natural compound.

15.
Immunol Lett ; 103(2): 135-41, 2006 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-16313971

RESUMEN

HLA-B27 is a relative risk factor for ankylosing spondylitis (AS) and is present in about 10% in European populations but in 95% of AS patients. Various data suggest that the HLA-B27 molecule itself could be the strongest risk factor, but there is no explanation for this association. To define differential antigen presenting features of HLA-B27 in healthy individuals and AS patients, a question that cannot be addressed by biochemical studies on cell lines, the HLA-B27 protein was purified from peripheral blood lymphocytes of AS patients and healthy controls and pool sequencing of the bound peptides was performed. Results show that peptides are rich in proline (Pro) and the content of arginine (Arg) is much lower in comparison with sequences listed in the register of peptides eluted from cell cultures. Statistically significant differences were detected in frequencies of a subset of amino acids, predominantly at positions in the middle of the peptides. The frequency of Glu was increased and Gln was decreased in peptides from AS patients. Detailed analysis of purity of the immunoisolated HLA molecules excluded that the peptides might originate from any co-purified HLA molecules other than B27. We conclude that statistically significant increase in the Glu/Gln ratio of peptides from AS patients, consistent with increased deamidation in vivo, may account for differential antigenicity of HLA-B27 in patients. Source protein(s) of deamidated peptides remain unknown.


Asunto(s)
Antígeno HLA-B27/genética , Fragmentos de Péptidos/genética , Espondilitis Anquilosante/genética , Adulto , Arginina/genética , Femenino , Ácido Glutámico/genética , Glutamina/genética , Antígeno HLA-B27/química , Humanos , Masculino , Fragmentos de Péptidos/química , Prolina/genética , Factores de Riesgo , Análisis de Secuencia de Proteína
16.
J Chromatogr A ; 1120(1-2): 69-74, 2006 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-16364335

RESUMEN

The enantioseparation of 2-aryloxypropionic acids by capillary electrochromatography was tested on columns with a monolithic stationary phase prepared from silanized fused-silica capillaries (100 microm I.D.) by in situ copolymerization of glycidyl methacrylate, ethylene glycol dimethacrylate and methyl methacrylate in the presence of formamide and 1-propanol as the porogen solvents. The porous chiral monolithic stationary phases were prepared by reaction of the epoxy-groups at the surface of the monolith with (+)-1-(4-aminobutyl)-(5R,8S,10R)-terguride. To attain the minimum HETP values for the enantiodiscrimination of 2-phenoxypropionic acid, the influence of the composition of polymerization solution on column total porosity and efficiency was investigated. Optimum mobile phase conditions were found for all analytes tested using acetonitrile-methanol mixtures containing triethylamine and acetic acid as the buffer components. Furthermore, the chemical and mechanical stabilities of the columns were satisfactory, allowing hundreds of analyses.


Asunto(s)
Cromatografía Capilar Electrocinética Micelar/métodos , Propionatos/química , Ácido 2,4-Diclorofenoxiacético/análogos & derivados , Ácido 2,4-Diclorofenoxiacético/química , Ácido 2,4-Diclorofenoxiacético/aislamiento & purificación , Cromatografía Capilar Electrocinética Micelar/instrumentación , Compuestos Epoxi/química , Estudios de Evaluación como Asunto , Metacrilatos/química , Propionatos/aislamiento & purificación , Piridinas/química , Piridinas/aislamiento & purificación , Reproducibilidad de los Resultados , Dióxido de Silicio/química , Estereoisomerismo
17.
Fungal Biol ; 120(8): 917-930, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27521625

RESUMEN

Results of a survey and study of the Claviceps purpurea group of species in South Africa are being presented and five new species are described. Morphological descriptions are based on the anamorphs and four nuclear genetic loci. Claviceps fimbristylidis sp. nov. on Fimbristylis complanata was discovered wide-spread across five provinces of the country associated with water and represents the fourth Claviceps species recorded from the Cyperaceae. Claviceps monticola sp. nov. is described from Brachypodium flexum growing in mountain forests in Mpumalanga Province, as well as the northern Drakensberg southwards into the Eastern Cape Province. Claviceps pazoutovae sp. nov. is recorded from Stipa dregeana var. dregeana and Ehrharta erecta var. erecta, also associated with these mountain ranges. Claviceps macroura sp. nov. is recorded from Cenchrus macrourus from the Eastern Cape and Claviceps capensis sp. nov. from Ehrharta villosa var. villosa is recorded from the Western Cape Province. Claviceps cyperi, only recorded from South Africa is included in the study. Ergot alkaloid profiles of all species are provided and showed similarity to C. purpurea. Only C. cyperi and in lesser degree C. capensis, C. macroura, and C. pazoutovae produced ergot alkaloids in clinically significant amounts. Several reported species infect invasive grass species, native to South Africa, and thus represent potentially invasive species.


Asunto(s)
Claviceps/clasificación , Claviceps/aislamiento & purificación , Microbiología Ambiental , Alcaloides de Claviceps/análisis , Cromatografía Líquida de Alta Presión , Claviceps/química , Claviceps/genética , Análisis por Conglomerados , ADN de Hongos/química , ADN de Hongos/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Bosques , Componente 7 del Complejo de Mantenimiento de Minicromosoma/genética , Factor 1 de Elongación Peptídica/genética , Filogenia , Análisis de Secuencia de ADN , Sudáfrica , Tubulina (Proteína)/genética , Agua
18.
Sci Rep ; 6: 33200, 2016 09 13.
Artículo en Inglés | MEDLINE | ID: mdl-27620349

RESUMEN

Pathogenic and non-pathogenic related microorganisms differ in secondary metabolite production. Here we show that riboflavin overproduction by a fungal pathogen and its hyperaccumulation in affected host tissue exacerbates a skin infection to necrosis. In white-nose syndrome (WNS) skin lesions caused by Pseudogymnoascus destructans, maximum riboflavin concentrations reached up to 815 µg ml(-1), indicating bioaccumulation and lack of excretion. We found that high riboflavin concentrations are cytotoxic under conditions specific for hibernation, affect bats' primary fibroblasts and induce cell detachment, loss of mitochondrial membrane potential, polymerization of cortical actin, and cell necrosis. Our results explain molecular pathology of WNS, where a skin infection becomes fatal. Hyperaccumulation of vitamin B2 coupled with reduced metabolism and low tissue oxygen saturation during hibernation prevents removal of excess riboflavin in infected bats. Upon reperfusion, oxygen reacts with riboflavin resulting in dramatic pathology after arousal. While multiple molecules enable invasive infection, riboflavin-associated extensive necrosis likely contributes to pathophysiology and altered arousal pattern in infected bats. Bioaccumulation of a vitamin under natural infection represents a novel condition in a complex host-pathogen interplay.


Asunto(s)
Ascomicetos/patogenicidad , Quirópteros/microbiología , Dermatomicosis/microbiología , Riboflavina/metabolismo , Alas de Animales/microbiología , Animales , Ascomicetos/clasificación , Ascomicetos/genética , Adhesión Celular , Células Cultivadas , Fibroblastos/citología , Fibroblastos/metabolismo , Fibroblastos/microbiología , Interacciones Huésped-Patógeno , Potencial de la Membrana Mitocondrial , Microscopía Electrónica , Filogenia , Factores de Virulencia/metabolismo , Alas de Animales/citología , Alas de Animales/ultraestructura
19.
Folia Microbiol (Praha) ; 60(3): 259-67, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25416512

RESUMEN

A strain of Biatriospora sp. CCF 4378 was tested for the production of secondary metabolites under submerged fermentation conditions. Eleven compounds were isolated from the culture broth, and the structures of these compounds were determined using HRMS, NMR and X-ray analysis. In addition to six known naphthoquinone derivatives, i.e. ascomycone A, ascomycone B, 6-deoxyfusarubine, 6-deoxyanhydrofusarubine, herbarine and balticol A, one derivative of 2-azaanthraquinone, 6-deoxybostrycoidine, was also identified. Four new natural pyranonaphthoquinones were found, and these natural products were pleorubrin A, pleorubrin B, pleorubrin C and pleorubrin D. The toxicity on human cell lines of the crude naphthoquinone fraction and pure 6-deoxybostrycoidin, ascomycone B, pleorubrin B and 6-deoxyfusarubin was tested. Ascomycone B and 6-deoxyfusarubin elicited rapid cytotoxicity at micromolar concentrations.


Asunto(s)
Ascomicetos/aislamiento & purificación , Ascomicetos/metabolismo , Endófitos/aislamiento & purificación , Endófitos/metabolismo , Naftoquinonas/química , Naftoquinonas/metabolismo , Ulmus/microbiología , Ascomicetos/clasificación , Ascomicetos/genética , Línea Celular , Supervivencia Celular/efectos de los fármacos , Endófitos/clasificación , Endófitos/genética , Humanos , Estructura Molecular , Naftoquinonas/farmacología
20.
PLoS One ; 10(2): e0118913, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25723150

RESUMEN

Four strains of the fungus Quambalaria cyanescens (Basidiomycota: Microstromatales), were used for the determination of secondary metabolites production and their antimicrobial and biological activities. A new naphthoquinone named quambalarine A, (S)-(+)-3-(5-ethyl-tetrahydrofuran-2-yliden)-5,7,8-trihydroxy-2-oxo-1,4-naphthoquinone (1), together with two known naphthoquinones, 3-hexanoyl-2,5,7,8-tetrahydroxy-1,4-naphthoquinone (named here as quambalarine B, 2) and mompain, 2,5,7,8-tetrahydroxy-1,4-naphthoquinone (3) were isolated. Their structures were determined by single-crystal X-ray diffraction crystallography, NMR and MS spectrometry. Quambalarine A (1) had a broad antifungal and antibacterial activity and is able inhibit growth of human pathogenic fungus Aspergillus fumigatus and fungi co-occurring with Q. cyanescens in bark beetle galleries including insect pathogenic species Beauveria bassiana. Quambalarine B (2) was active against several fungi and mompain mainly against bacteria. The biological activity against human-derived cell lines was selective towards mitochondria (2 and 3); after long-term incubation with 2, mitochondria were undetectable using a mitochondrial probe. A similar effect on mitochondria was observed also for environmental competitors of Q. cyanescens from the genus Geosmithia.


Asunto(s)
Basidiomycota/metabolismo , Productos Biológicos/metabolismo , Fermentación , Antiinfecciosos/química , Antiinfecciosos/aislamiento & purificación , Antiinfecciosos/metabolismo , Antiinfecciosos/farmacología , Productos Biológicos/química , Productos Biológicos/aislamiento & purificación , Productos Biológicos/farmacología , Línea Celular , Humanos , Pruebas de Sensibilidad Microbiana
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