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1.
Braz. j. microbiol ; 45(2): 661-665, Apr.-June 2014. ilus, tab
Article Dans Anglais | LILACS | ID: lil-723133

Résumé

The req_39680 gene, associated to a putative efflux system, was detected in 60% (54/90) of R. equi isolates by PCR. The phenotypic expression of efflux mechanism was verified in 20% of the isolates using ethidium bromide. For the first time, the expression of efflux mechanism was demonstrated in R. equi.


Sujets)
Protéines de transport membranaire/génétique , Protéines de transport membranaire/métabolisme , Rhodococcus equi/génétique , Rhodococcus equi/métabolisme , Transport biologique actif , ADN bactérien/génétique , Éthidium/métabolisme , Réaction de polymérisation en chaîne
2.
Braz. j. infect. dis ; 12(2): 108-114, Apr. 2008. ilus
Article Dans Anglais | LILACS | ID: lil-486310

Résumé

Evaluation of apoptosis by flow cytometry is generally accomplished by methods that use annexin V-FITC as vital dye, which access phosphatidylserine exposed on the external membrane at the beginning of this process. In addition, the concomitant use of propidium iodide makes possible to verify the characteristic nuclear alterations in the late stages of apoptosis, as a consequence of the increase in membrane permeability. On the other hand, the use of calcein-AM in association with ethidium homodimer (EthD-1) allows the evaluation of cell apoptosis through detection of esterase activity and cellular membrane physical and chemical alterations. The aim of this study was to compare the sensibility of calcein-AM and EthD-1 with annexin V-FITC and propidium iodide for early apoptosis evaluation in peripheral blood mononuclear cell culture, obtained from HIV-infected patients. Apoptosis and cellular viability were detected and quantified by flow cytometry after 24 and 48 hours incubation times. Our results showed that calcein-AM/EthD-1 was more sensitive for apoptotic cell quantification in both incubation times than annexin V-FITC/propidium iodide (mean of 46.95 percent ± 3.56, p < 0.0001, for 24 hours and mean of 37.67 percent ± 2.47, p < 0.0014 for 48 hours), besides allowing to clearly define viable, apoptotic and dead cell populations.


Sujets)
Humains , Apoptose , /métabolisme , Cytométrie en flux/méthodes , Fluorescéines/métabolisme , Colorants fluorescents/métabolisme , Infections à VIH/anatomopathologie , Lymphocytes/physiologie , Marqueurs biologiques/métabolisme , Perméabilité des membranes cellulaires , Éthidium/analogues et dérivés , Éthidium/métabolisme , Propidium/métabolisme , Sensibilité et spécificité , Facteurs temps
4.
Experimental & Molecular Medicine ; : 204-209, 2000.
Article Dans Anglais | WPRIM | ID: wpr-25122

Résumé

DNA binding compounds were previously shown to bind to the right-handed DNA forms and hybrid B-Z forms in a highly cooperative manner and indicate that structural specificity plays a key role in a ligand binding to DNA. In this study, the modes of binding and structural specificity of agents to unusual DNA are examined by a variety of fluorescence techniques (intensity, polarization and quenching, etc.) to explore a reliable method to detect the association environment of ligands to deoxyoligonucleotides initially containing a B-Z junction between the left-handed Z-DNA and right-handed B-DNA. The results of fluorescence energy transfer measurement demonstrated that the ligand molecules bind to the allosterically converted DNA structures by intercalation. In the absence of high-resolution structural data, this fluorescence energy transfer measurement allowed reliable measures and infer the binding environment of ligands to the allosteric DNA structures.


Sujets)
Régulation allostérique , Dichroïsme circulaire , ADN/composition chimique , Transfert d'énergie , Éthidium/métabolisme , Exodeoxyribonucleases/métabolisme , Ligands , Déplacement , Conformation d'acide nucléique , Oligodésoxyribonucléotides/métabolisme
5.
Braz. j. med. biol. res ; 31(7): 933-6, jul. 1998. ilus
Article Dans Anglais | LILACS | ID: lil-212871

Résumé

Multiple episodes of blood-brain barrier disruption were induced by sequential intraspinal injections of ethidium bromide. In addition to the barrier disruption, there was toxic demyelination and exposure of myelin components to the immune system. Twenty-seven 3-month-old Wistar rats received 2, 3 or 4 injections of 1 mul of either 0.1 percent ethidium bromide in normal saline (19 rats) or 0.9 percent saline (8 rats) at different levels of the spinal cord. The time intervals between the injections ranged from 28 to 42 days. Ten days after the last injection, all rats were perfused with 2.5 percent glutaraldehyde. The spinal sections were evaluated macroscopically and by light and transmission electron microscopy. All the lesions demonstrated a mononuclear phagocytic infiltrate apparently removing myelin. Lymphocytes were not conspicuos and were found in only 34 percent of the lesions. No perivascular cuffings were detected. In older lesions (38 days and older) they were found only within Virchow-Robin spaces. This result suggests that multiple blood-brain barrier disruptions with demyelination and exposure of myelin components to the immune system were not sufficient to induce an immune-mediated reaction in the central nervous system.


Sujets)
Animaux , Rats , Femelle , Barrière hémato-encéphalique/immunologie , Maladies démyélinisantes/induit chimiquement , Maladies démyélinisantes/immunologie , Éthidium/toxicité , Sclérose en plaques/immunologie , Antagonistes nicotiniques/toxicité , Moelle spinale/immunologie , Système nerveux central/immunologie , Système nerveux central/anatomopathologie , Maladies démyélinisantes/anatomopathologie , Éthidium/métabolisme , Injections rachidiennes , Lymphocytes/ultrastructure , Microscopie électronique , Sclérose en plaques/anatomopathologie , Protéine basique de la myéline , Antagonistes nicotiniques/métabolisme , Rat Wistar
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