Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Más filtros

Banco de datos
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Antimicrob Agents Chemother ; 53(2): 458-64, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19015349

RESUMEN

Infections with Giardia lamblia, Entamoeba histolytica, and Trichomonas vaginalis, which cause diarrhea, dysentery, and vaginitis, respectively, are each treated with metronidazole. Here we show that Giardia, Entamoeba, and Trichomonas have oxygen-insensitive nitroreductase (ntr) genes which are homologous to those genes that have nonsense mutations in metronidazole-resistant Helicobacter pylori isolates. Entamoeba and Trichomonas also have nim genes which are homologous to those genes expressed in metronidazole-resistant Bacteroides fragilis isolates. Recombinant Giardia, Entamoeba, and Trichomonas nitroreductases used NADH rather than the NADPH used by Helicobacter, and two recombinant Entamoeba nitroreductases increased the metronidazole sensitivity of transformed Escherichia coli strains. Conversely, the recombinant nitroimidazole reductases (NIMs) of Entamoeba and Trichmonas conferred very strong metronidazole resistance to transformed bacteria. The Ehntr1 gene of the genome project HM-1:IMSS strain of Entamoeba histolytica had a nonsense mutation, and the same nonsense mutation was present in 3 of 22 clinical isolates of Entamoeba. While ntr and nim mRNAs were variably expressed by cultured Entamoeba and Trichomonas isolates, there was no relationship to metronidazole sensitivity. We conclude that microaerophilic protists have bacterium-like enzymes capable of activating metronidazole (nitroreductases) and inactivating metronidazole (NIMs). While Entamoeba and Trichomonas displayed some of the changes (nonsense mutations and gene overexpression) associated with metronidazole resistance in bacteria, these changes did not confer metronidazole resistance to the microaerophilic protists examined here.


Asunto(s)
Amebicidas/metabolismo , Antiprotozoarios/metabolismo , Antitricomonas/metabolismo , Entamoeba/enzimología , Giardia/enzimología , Metronidazol/metabolismo , Nitrorreductasas/metabolismo , Trichomonas/enzimología , Amebicidas/farmacología , Secuencia de Aminoácidos , Animales , Antiprotozoarios/farmacología , Antitricomonas/farmacología , Bacteroides/genética , Biotransformación , Codón sin Sentido , Farmacorresistencia Bacteriana/genética , Entamoeba/efectos de los fármacos , Giardia/efectos de los fármacos , Helicobacter/genética , Metronidazol/farmacología , Datos de Secuencia Molecular , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Trichomonas/efectos de los fármacos
2.
J Nanosci Nanotechnol ; 7(9): 3193-9, 2007 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18019149

RESUMEN

This article reports the synthesis, characterization and also the use of surface modified iron oxide nanoparticles in affinity separation of his-tagged protein. Magnetite particles were prepared by simple coprecipitation of Fe3+/Fe2+ in aqueous medium and then subsequently coated with silica following a sol-gel route. Iminodiacetate was immobilized on them through a silane-coupling agent and charged with Ni2+. These Ni2+ charged magnetic silica nanoparticles have been shown as an efficient carrier, binder and anchor to obtain his-tagged protein directly from total cell lysate. The structural characteristics of the powders were studied by XRD. Magnetic silica particles with 12 nm and aggregate size 90 nm containing inverse spinel magnetite core were observed by transmission electron micrograph and dynamic light scattering. The presence of surface-iminodiacetate groups was shown by FTIR and X-ray photoelectron spectra. The immobilization of Ni2+ through the surface chelating iminodiacetate groups was also studied by XPS. VSM measurement shows these iminodiacetate functionalized magnetic carriers have saturation magnetization 56 e.m.u./g at room temperature. Due to its high efficiency, cost-effectiveness, biocompatibility, and versatility, this magnetic nano-adsorbent may be used as a novel purification system for 6xHis-Tagged recombinant proteins.


Asunto(s)
Compuestos Férricos/química , Nanopartículas del Metal/química , Cloruros , Cromatografía de Afinidad/métodos , Luz , Magnetismo , Modelos Químicos , Nanopartículas/química , Níquel/química , Proteínas Recombinantes/química , Dispersión de Radiación , Silanos/química , Espectrometría por Rayos X/métodos , Espectroscopía Infrarroja por Transformada de Fourier
3.
Probiotics Antimicrob Proteins ; 2(3): 152-61, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26781238

RESUMEN

The Gram-positive thin rods of a Bacillus species were identified and designated as Bacillus coagulans RK - 02 through the standard microbiological and biochemical characterization procedures, followed by data analysis and comparison with the characteristics given in Bergey's manual of systematic bacteriology. The culture was further characterized and confirmed as Bacillus coagulans by 16S rDNA sequence analysis wherein about 755 nucleotides of 16S rDNA was amplified and cloned in pGEM-T vector and subsequently sequenced. Sequence was blasted against the nr database of NCBI. Multiple alignments were done with some selected and related sequences using Clustal W. Phylogenetic trees were drawn with the same software after the distances were determined by neighbor-joining algorithm. The in vitro studies on the probiotic properties demonstrated that our isolate could prove to be a potential probiotic with spore-forming and lactic acid-producing abilities coupled with acid and bile tolerance properties and antimicrobial action. In addition to these characteristics, the bacterium also produced enzymes such as amylase, cellulase, lipase, protease, lactase and catalase, which can help in improving digestion and overall health, alleviate lactose intolerance and remove oxidative stresses, required for the well-being of the consumers. In our previously reported studies, an exopolysaccharide (EPS), a probioactive molecule produced by the same bacterium, showed very significant antioxidant, antihyperglycemic and emulsification activities. Thus, Bacillus coagulans RK - 02 is a well-characterized promising probiotic for its potential commercial applications to pharmaceutical, nutraceutical and functional food formulations with care-free storage.

4.
Exp Parasitol ; 113(4): 239-43, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16515787

RESUMEN

MicroRNAs are an abundant class of approximately 20-24-nucleotide noncoding RNAs that control the expression of several genes at the post-transcriptional level, regulating several important biochemical pathways. MicroRNAs have been identified in many vertebrates including humans, and also in flies, nematodes, plants, and viruses. In the present work we have identified seventeen putative candidate microRNAs in the pathogenic parasite Entamoeba histolytica using a bioinformatic approach. Putative microRNA identification in E. histolytica may act as a starting reference for cloning and characterization of miRNAs in Entamoeba genome.


Asunto(s)
Entamoeba histolytica/genética , MicroARNs/análisis , ARN Protozoario/análisis , Animales , MicroARNs/química , Conformación de Ácido Nucleico , ARN Protozoario/química , Secuencias Repetitivas de Ácidos Nucleicos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA