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1.
Persoonia ; 41: 202-212, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30728605

RESUMEN

Four new species of Hohenbuehelia (Fungi: Pleurotaceae) are described in the group of Hohenbuehelia atrocoerulea and Hohenbuehelia grisea. Hohenbuehelia algonquinensis, found on Pinus in Ontario, Canada, may be distinguished macroscopically from bluish collections of H. atrocoerulea and watery grey-brown collections of H. grisea by its coal-black pileus. Hohenbuehelia canadensis, on or associated with Pinus in both Ontario and Alberta, Canada, and Hohenbuehelia nimueae, on Salix in Ontario and Abies in Wyoming, USA, have similarly dark fruiting bodies and were previously misidentified as H. approximans (which we treat as a synonym of H. grisea), H. atrocoerulea, H. mustialensis or H. nigra. The latter species is shown to be a member of Resupinatus, despite the presence of prominent metuloid cystidia in its hymenium. Hohenbuehelia carlothornii has been found in Costa Rica; collections of the sexual fruiting bodies were previously identified as H. grisea and isolates from soil nematodes were identified by the anamorph name Nematoctonus robustus. That name has been treated as a synonym of H. atrocoerulea but, given the genetic and geographic variation within this complex, we transfer it to Hohenbuehelia as a distinct species. Sequences of the nuclear ribosomal DNA internal transcribed spacer region (ITS), the D1/D2 variable region of the large subunit gene, and a portion of the translation elongation factor (TEF1) gene provide good separation and support for these new species. A key to the dimidiate species of Hohenbuehelia of North America and Europe is provided.

2.
J Am Chem Soc ; 139(28): 9534-9543, 2017 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-28651046

RESUMEN

Heparan sulfates (HS) are linear sulfated polysaccharides that modulate a wide range of physiological and disease-processes. Variations in HS epimerization and sulfation provide enormous structural diversity, which is believed to underpin protein binding and regulatory properties. The ligand requirements of HS-binding proteins have, however, been defined in only a few cases. We describe here a synthetic methodology that can rapidly provide a library of well-defined HS oligosaccharides. It is based on the use of modular disaccharides to assemble several selectively protected tetrasaccharides that were subjected to selective chemical modifications such as regioselective O- and N-sulfation and selective de-sulfation. A number of the resulting compounds were subjected to enzymatic modifications by 3-O-sulfotransferases-1 (3-OST1) to provide 3-O-sulfated derivatives. The various approaches for diversification allowed one tetrasaccharide to be converted into 12 differently sulfated derivatives. By employing tetrasaccharides with different backbone compositions, a library of 47 HS-oligosaccharides was prepared and the resulting compounds were used to construct a HS microarray. The ligand requirements of a number of HS-binding proteins including fibroblast growth factor 2 (FGF-2), and the chemokines CCL2, CCL5, CCL7, CCL13, CXCL8, and CXCL10 were examined using the array. Although all proteins recognized multiple compounds, they exhibited clear differences in structure-binding characteristics. The HS microarray data guided the selection of compounds that could interfere in biological processes such as cell proliferation. Although the library does not cover the entire chemical space of HS-tetrasaccharides, the binding data support a notion that changes in cell surface HS composition can modulate protein function.


Asunto(s)
Factores de Crecimiento de Fibroblastos/química , Heparitina Sulfato/química , Análisis por Micromatrices , Animales , Sitios de Unión , Conformación de Carbohidratos , Línea Celular , Proliferación Celular , Ligandos , Ratones , Resonancia por Plasmón de Superficie
3.
Q J Nucl Med Mol Imaging ; 59(4): 381-99, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26337240

RESUMEN

Prostate cancer bone metastases occur frequently in advanced cancer and this is matter of particular attention, due to the great impact on patient's management and considering that a lot of new emerging therapeutic options have been recently introduced. Imaging bone metastases is essential to localize lesions, to establish their size and number, to study characteristics and changes during therapy. Besides radiological imaging, nuclear medicine modalities can image their features and offer additional information about their metabolic behaviour. They can be classified according to physical characteristics, type of detection, mechanism of uptake, availability for daily use. The physiopathology of metastases formation and the mechanisms of tracer uptake are essential to understand the interpretation of nuclear medicine images. Therefore, radiopharmaceuticals for bone metastases can be classified in agents targeting bone (99mTc-phosphonates, 18F-fluoride) and those targeting prostatic cancer cells (18F-fluoromethylcholine, 11C-choline, 18F-fluorodeoxyglucose). The modalities using the first group of tracers are planar bone scan, SPECT or SPECT/CT with 99mTc-diphosphonates, and 18F-fluoride PET/CT, while the modalities using the second group include 18F/11C-choline derivatives PET/CT, 18F-FDG PET/CT and PET/CT scans with several other radiopharmaceuticals described in the literature, such as 18F/11C-acetate derivatives, 18F-fluoro-5α-dihydrotestosterone (FDHT), 18F-anti-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC), 18F-2'-fluoro-5-methyl-1-ß-D-arabinofuranosyluracil (FMAU) and 68Ga-labeled-prostate specific membrane antigen (PMSA) PET/TC. However, since data on clinical validation for these last novel modalities are not conclusive and/or are not still sufficient in number, at present they can be still considered as promising tools under evaluation. The present paper considers the nuclear modalities today available for the clinical routine. This overview wants to discuss the opportunities and the drawbacks of these current diagnostic tests in a scenario where planar scintigraphy and/or SPECT with phosphonates, is the only metabolic imaging recommended by the most important Guidelines of the Scientific Societies dealing with prostate cancer. Other nuclear medicine modalities are in very few cases just cited, never recommended except in rare situations. Is there space for agents other than 99mTc-phosphonates to image bone lesions from prostate cancer?


Asunto(s)
Neoplasias Óseas/diagnóstico , Neoplasias Óseas/secundario , Huesos/metabolismo , Diagnóstico por Imagen/métodos , Organofosfonatos , Neoplasias de la Próstata/patología , Tecnecio , Animales , Neoplasias Óseas/metabolismo , Huesos/diagnóstico por imagen , Humanos , Masculino , Radiografía , Cintigrafía
4.
Biosens Bioelectron ; 20(10): 2019-26, 2005 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-15741071

RESUMEN

The prototype of an amperometric glucose biosensor was realized by thermal inkjet printing using biological and electronic water-based inks, containing a glucose oxidase (GOD) from Aspergillus niger and the conducting polymer blend poly(3,4-ethylenedioxythiophene/polystyrene sulfonic acid) (PEDOT/PSS), respectively. The biosensor was fabricated microdepositing PEDOT/PSS and GOD, in sequence, on ITO-glass, by a commercial inkjet printer, with the help of a commercial software. High density microdots matrices were so-realized, with a calculated resolution of about 221 x 221 dpi (dot per inch). By means of a rapid and easy assay it was demonstrated that no activity loss occurred upon the printing of GOD, despite of the use of a thermal printhead. The device was encapsulated in a semipermeable membrane of cellulose acetate, applied by dip-coating, in order to prevent dissolution of the enzyme and/or PEDOT/PSS in water. The preliminary response of the electrode was measured in an aqueous glucose solution in the presence of ferrocenemethanol (FeMeOH) as a mediator, and resulted linear up to 60 mM in glucose. The best sensitivity value achieved was 6.43 microAM(-1) cm(-2) (447 nAM(-1) U(-1) cm(-2)). The characteristics of the device, and the possible performance improvements have been analyzed and discussed. The reported findings indicate that inkjet printing could be a viable instrument for the easy construction of a working biosensor via direct digital design using biological and conductive polymer based inks. Such an approach may be seen as an example of "biopolytronics".


Asunto(s)
Técnicas Biosensibles/instrumentación , Electroquímica/instrumentación , Glucosa Oxidasa/química , Glucosa/análisis , Glucosa/química , Aspergillus niger/enzimología , Técnicas Biosensibles/métodos , Glucemia/análisis , Materiales Biocompatibles Revestidos/química , Periféricos de Computador , Electroquímica/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Estudios de Factibilidad , Glucosa Oxidasa/análisis , Calor , Proyectos Piloto , Impresión/instrumentación
5.
Ann Chim ; 91(7-8): 503-15, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11554188

RESUMEN

Supercritical fluid extraction (SFE) has proven to be a method for the extraction of pollutants from the soil having serious difficulties to be standardized. A new possibility to use SFE for investigate the fate of pollutants in the soil structure is suggested. The recovery of the analyte from the soil matrix depends on the mass transfer. This includes the desorption of the analyte from the soil surface, its diffusion through the interior of the soil structure, and its transport within the bulk flow of supercritical fluid through the interstitial pores of the soil. The mass transfer can be expected to depend on both the different types of soil and the different location of the analyte in the soil structure. The analyte extraction is also controlled by thermodynamic factors such as the sorption/desorption equilibrium from the soil. On this basis, a mathematical model based on the supercritical fluid extraction conditions (viz, temperature, pressure, fluid flow, modifier,...), which are directly linked to the status of the analyte in the soil, is developed. The elaboration of the kinetical results using our model would permit to approximate the distribution of the contaminant to a non porous- or to a deep porous-soil structure model as a function of a fresh contamination or an aged contamination. These conditions can be described by spiked or native contaminant extraction time profiles, respectively.


Asunto(s)
Cromatografía con Fluido Supercrítico/métodos , Monitoreo del Ambiente/métodos , Contaminantes del Suelo/análisis , Cinética , Compuestos Orgánicos/análisis , Reproducibilidad de los Resultados , Factores de Tiempo
7.
Appl Microbiol Biotechnol ; 52(1): 111-7, 1999 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10461376

RESUMEN

Biocatalytic desulfurization is still not a commercial technology, but conceptual engineering and sensitivity analyses have shown that the approach is very promising. The purpose of this paper is to investigate further some aspects of the biodesulphurization pathways, discussing the non-destructive pathway with the well-known Rhodococcus rhodochrous IGTS8. Findings revealed byproducts, such as 2'-hydroxybiphenyl (HBP), sulfite and sulfate, obtained by the desulfurization of dibenzothiophene (DBT), to exert an inhibiting effect. The results suggest that IGTS8 may follow two different metabolic pathways in stationary-growth-phase cells or under growing conditions. The first pathway is characterized by oxidative steps, which convert DBT to DBT sulfoxide and to DBT sulfone. The sulfone is transformed to 2-(2'-hydroxyphenyl)benzene sulfinate and then to HBP and sulfite by a sulfinic acid hydrolase. In the second pathway the sulfone is further oxidized to 2-(2'-hydroxyphenyl)benzene sulfonate and then to HBP and sulfate by a sulfonic acid hydrolase. Experiments using benzene sulfonic acid suggest that the sulfonic acid hydrolase is an induced enzyme.

9.
Can J Microbiol ; 44(3): 289-97, 1998 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9606911

RESUMEN

Rhizobium meliloti Orange 1 was isolated from aerobic sediments of a drainage ditch receiving oil refinery leakage. This bacterium has been shown to be capable of growing on dibenzothiophene as the sole carbon and energy source. This strain can also efficaciously nodulate alfalfa plants. In cultures with dibenzothiophene, Orange 1 produces six degradation intermediates. By means of analyses with UV-visible and GC-MS spectrometry, as well as nuclear magnetic resonance spectroscopy, three of these products were identified as 3-hydroxy-2-formyl-benzothiophene (product A), benzothienopyran-2-one (product B'), and dibenzothiophene-5-oxide (product D). This suggests that R. meliloti Orange 1 metabolizes dibenzothiophene via oxidative cleavage of the aromatic ring with a mechanism analogous to that described for naphthalene degradation.


Asunto(s)
Sinorhizobium meliloti/aislamiento & purificación , Sinorhizobium meliloti/metabolismo , Tiofenos/metabolismo , Biodegradación Ambiental , Cromatografía de Gases y Espectrometría de Masas , Residuos Industriales , Imagen por Resonancia Magnética , Petróleo/metabolismo , Sinorhizobium meliloti/crecimiento & desarrollo
10.
Appl Biochem Biotechnol ; 55(3): 207-18, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8579344

RESUMEN

Vaccinium mirtyllus peroxidase solubilized in reversed micelles was used for the oxidation of guaiacol. Some relevant parameters for the enzymatic activity, such as pH, w(o) (molar ratio water/surfactant), surfactant type and concentration, and cosurfactant concentration, were investigated. The peroxidase showed higher activities in reversed micelles than in aqueous solution. The stability of the peroxidase in reversed micelles was also studied, namely, the effect of w(o) and temperature on enzyme deactivation. The peroxidase displayed higher stabilities in CTAB/hexanol in isooctane reversed micelles, with half-life times higher than 500 h.


Asunto(s)
Micelas , Peroxidasas/metabolismo , Cetrimonio , Compuestos de Cetrimonio/química , Medios de Cultivo , Detergentes/química , Estabilidad de Enzimas/fisiología , Frutas/enzimología , Guayacol/química , Hexanoles/química , Concentración de Iones de Hidrógeno , Octanos/química , Oxidación-Reducción , Peroxidasas/química , Solubilidad , Tensoactivos/química , Temperatura
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