182 resultados para agarose gel


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The effect of changes in the bulk dielectric constant on the DNA torsional properties was evaluated from plasmid circularization reactions. In these reactions, pUC18 previously linearized by EcoRI digestion was recircularized with T4 DNA ligase. The bulk dielectric constant of the reaction medium was decreased by the addition of different concentrations of neutral solutes: ethylene glycol, glycerol, sorbitol, and sucrose, or increased by the addition of glycine. The topoisomers generated by the ligase reaction were resolved by agarose-gel electrophoresis. The DNA twist energy parameter (K), which is an apparent torsional constant, was determined by linearization of the Gaussian topoisomers' distribution. It was observed that the twist energy parameter for the given solutes is almost linearly dependent on the bulk dielectric constant. In the reaction buffer, the twist energy parameter was determined to be 1100 +/- 100. By decreasing the dielectric constant to 74 with the addition of sorbitol, the value of the parameter reaches K = 900 +/- 100, whereas the addition of ethylene glycol leads to kappa = 400 +/- 50. Upon addition of glycine, which resulted in a dielectric constant equal to 91, the value of the twist energy parameter increased to K 1750 +/- 100. (c) 2007 Wiley Periodicals.

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A hiper-homocisteinemia, resultante da deficiência na conversão da homocisteína em cistationina, constitui em fator de risco isolado para doenças vasculares. A mutação 844ins68 do gene da cistationina beta-sintetase é um fator adicional de risco para a trombose venosa profunda. O objetivo deste estudo foi avaliar a freqüência da mutação 844ins68 do gene da cistationina beta-sintetase em pacientes com trombose venosa profunda. Foram avaliados em estudo caso-controle 95 pacientes com trombose venosa profunda, a presença da mutação 844ins68 no éxon 8 do gene da cistationina beta-sintetase. Como critério de inclusão foi adotada a presença de trombose venosa profunda confirmada pelo dúplex ou flebografia. O grupo controle constituiu-se de 95 doadores de sangue, sem história familiar prévia de trombose venosa, com sexo, grupo étnico e idades pareados aos do grupo de estudo. Foram coletados 5 mL de sangue venoso com o uso de anticoagulante EDTA de cada participante. O DNA foi extraído dos leucócitos pelo método DTAB e CTAB. A detecção da mutação do gene foi realizada por amplificação de um segmento gênico por PCR, com iniciadores que flanqueiam a região de inserção e com revelação em gel de agarose a 2%, corado com brometo de etídio, sob luz UV. O fragmento correspondente ao alelo normal contém 184 pares de base e o correspondente ao alelo mutante, 252 pares de base. O teste exato de Fisher foi utilizado na análise dos resultados. A condição heterozigota para a mutação foi encontrada em 14,73% dos pacientes e em 3,1% dos indivíduos do grupo controle (p = 0,009). A freqüência do alelo mutante mostrou diferença significativa (p = 0,01), sendo 0,074 para os pacientes versus 0,016 para o grupo controle. Não foram encontrados casos de homozigose.

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A doença falciforme é um termo genérico usado para determinar um grupo de alterações genéticas caracterizadas pelo predomínio de hemoglobina (Hb) S. Os principais genótipos que compõem o grupo de doença falciforme são os seguintes: SS, SF [S/beta0 talassemia e S/persistência hereditária de Hb fetal (PHHF)], SFA (S/beta+ talassemia), SC, SD e SH (S/alfa talassemia). O presente trabalho analisa os resultados das avaliações de produtos provenientes da oxidação da Hb S, identificados pela concentração da metemoglobina e de eritrócitos com corpos de Heinz em dois genótipos da doença falciforme (SS e S/beta0 talassemia) e no traço falcêmico (AS), em comparação com o genótipo normal (AA). A análise dos produtos da degradação oxidativa da hemoglobina, evidenciados pelo aumento dos valores das médias referentes à concentração de metemoglobina e do número de eritrócitos com corpos de Heinz, está diretamente relacionada com o aumento da concentração da Hb S. Assim, a degradação oxidativa da hemoglobina decresce entre os genótipos estudados da seguinte forma: SS>SF>AS>AA. É importante destacar que as análises indicaram que a simples presença de Hb S no eritrócito, como é o caso do genótipo AS, é capaz de causar elevação da concentração de metemoglobina em 52,62% das amostras analisadas e de induzir a precipitação de corpos de Heinz em 73,68% dos casos estudados. Explicações referentes aos processos oxidativos e redutores das hemoglobinas estudadas são apresentados no texto. Destaca-se, entre os resultados apresentados, a identificação por meio de eletroforese em agarose alcalina da fração de globina alfa-livre em todas as amostras do genótipo SF provenientes de pessoas com Hb S/beta0 talassemia. É proposto um esquema para explicar a origem da globina alfa-livre, especialmente para o genótipo S/beta0 talassemia, e a importância da sua identificação no diagnóstico laboratorial de Hb S/beta0 talassemia.

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Purpose: To characterize the vitreous intrinsic proteoglycans, investigate their dynamics, and examine their role in the supramolecular organization of the vitreous. Methods: Vitreous from normal rabbits was collected and processed for observation with the transmission electron microscope after treatment with glycosidases. Also, rabbits were injected intravitreally with [S-35]-sodium sulfate and sacrificed at several time intervals after the injection. Proteoglycans (PGs) were assayed in the vitreous supernatant or in whole samples extracted with guanidine hydrochloride by polyacrylamide or agarose gel electrophoresis, followed respectively by fluorography or autoradiography, and ion-exchange chromatography and gel-filtration chromatography, combined with glycolytic treatment of the samples. The sulfated glycosaminoglycans (GAGs) were characterized by agarose gel electrophoresis after treating vitreous samples with protease and specific glycosidases. Results: the electron microscopic study revealed a network with hyaluronic acid ( HA) as thin threads coating and connecting collagen fibrils. The elimination of the HA coat showed chondroitin sulfate granules (8-25 nm) arranged at regular intervals on the fibril surface. The chondroitinase ABC digestion, besides removing the granules, also caused the formation of thicker bundles of the collagen fibrils. The PG and GAG analysis indicated that there are three renewable PGs in the vitreous ( e. g., one heparan-and two chondroitin-sulfate ones). Conclusions: At least one of the chondroitin sulfate PGs is involved in the interactions that occur in the vitreous structure, mainly by providing adequate spacing between the collagen fibrils, a condition that is probably required for the transparency of the vitreous.

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This work is aimed to determine the profile of electrophoretic serum protein in healthy adult broiler breeders (Gallus gallus domesticus) of the Avian farm strain. Fifteen breeders aging 63 weeks from Conchas, city located in the State of São Paulo, were assessed. The biuret method was used to obtain the total serum protein values and protein fractions separation through electrophoresis technique in agarose gel, and film reading through densitometry in 520nM. Seven fractions were obtained, whereas, β 1 - globulin and β 2 - globulin were not cited by the authors in the textbooks checked. The prealbumin fraction was identified only in six out of 15 samples analyzed. In five breeders, it was observed the division of g - globulin into two fractions named g - 1 and g - 2, according to the electrophoretic mobilities. The relation albumin/globulin (A/G) found in the experiment agrees with the other authors cited, demonstrating that it decreases as the age increases.

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Esophageal-pharyngeal fluids from 53 free-ranging marsh deer (Blastocerus dichotomus) captured for a research program in the state of Mato Grosso do Sul, Brazil, were assayed for tuberculosis. Total DNA was extracted, amplified by polymerase chain reaction using specific primers for Mycobacterium tuberculosis complex (M. tuberculosis, M. bovis, M. microti, and M. africanum), and observed by agarose gel electrophoresis stained with ethidium bromide. All samples were negative. This, along with necropsy and histopathology data, suggests that these animals are not shedding and probably do not have active disease.

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This study was performed in order to evaluate the detection limit of PCR with fluorescent capillary electrophoresis for Leptospira pomona diagnosis in bovine semen. Negative bovine semen samples were artificially contaminated with Leptospira pomona (10 0 to 10 7 bacteria/ ml) and DNA was extracted by phenol/chloroform protocol. DNA fragments visualization was done by three electrophoresis methods: under UV light in 2 % agarose gel, silver staining 8% polyacrylamide gel and fluorescent capillary electrophoresis. The detection limit of capillary electrophoresis for Leptospira pomona was 10 2bacteria/ml. Under UV light, in 2 % agarose gel, the detection limit was of 10 4 bacteria/ ml while for silver stained 8 % polyacrylamide gel it was 10 2 bacteria/ ml. PCR with fluorescent capillary electrophoresis is an efficient and rapid diagnostic test for DNA detection of Leptospira in bovine semen and this can be an important tool for herd and semen sanitary control in artificial insemination centers.

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Cysticercosis is one of the most important zoonosis, not only because of the effects on animal health and its economic consequences, but also due to the serious danger it poses to humans. The two main parasites involved in the taeniasis-cysticercosis complex in Brazil are Taenia saginata and Taenia solium. Differentiating between these two parasites is important both for disease control and for epidemiological studies. The purpose of this work was to identify genetic markers that could be used to differentiate these parasites. Out of 120 oligonucleotide decamers tested in random amplified polymorphic DNA (RAPD) assays, 107 were shown to discriminate between the two species of Taenia. Twenty-one DNA fragments that were specific for each species of Taenia were chosen for DNA cloning and sequencing. Seven RAPD markers were converted into sequence characterized amplified region (SCAR) markers with two specific for T. saginata and five specific for T. solium as shown by agarose gel electrophoresis. These markers were developed as potential tools to differentiate T. solium from T. saginata in epidemiological studies. © 2007 Elsevier Inc. All rights reserved.

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Purpose: To detect the occurrence and expression of the suppressor gene p53 and of the oncogene c-Myc in eyelid tumors of dogs using the PCR, RT-PCR, PCR-ELISA and RT-PCR-ELISA techniques. These genes have not been described in dog eyelid tumors before. Methods: Nine samples of eyelid or third eyelid epithelial tumors were obtained from the archives of the Department of Veterinary Pathology. Tumor diagnosis was confirmed by evaluation of hematoxylin-eosin stained sections, and immunohistochemistry for cytokeratin AE1/AE3 and vimentin V9. A canine mammary tumor was used for positive control. Agarose gel electrophoresis, PCR-ELISA and RT-PCR-ELISA were used to detect p53 and c-Myc genes. Results: The occurrence of p53 was detected in most of the eyelid tumors and third eyelid tumors studied (88.8%, n = 8) and was expressed in 75% of the positive samples, as indicated by ELISA. The c-Myc gene was found in 77.7% (n = 7) of the samples and was expressed in eight samples. Conclusions: Eyelid and third eyelid tumors of dogs express both the p53 and the c-Myc genes as shown by PCR and RT-PCR. However, PCR ELISA and RT-PCR ELISA were more efficient in assessing occurrence and expression of these genes because they identified amplified products that were not detected by agarose gel electrophoresis. © 2010 American College of Veterinary Ophthalmologists.

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Albumin concentrations in female Bronze turkeys were compared using agarose gel electrophoresis (AGE) and the bromocresol green (BCG) dye-binding method. The correlation coefficient observed for albumin in the BCG and AGE methods was low, and statistical differences were observed at paired t test (p < 0. 0001). Compared with electrophoresis, the BCG-binding method yielded significantly lower albumin values for female turkeys during laying season. © 2011 Springer-Verlag London Limited.

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Cationic lipids have been used in the development of non-viral gene delivery systems as lipoplexes. Stearylamine, a cationic lipid that presents a primary amine group when in solution, is able to compact genetic material by electrostatic interactions. In dispersed systems such as nanoemulsions this lipid anchors on the oil/water interface confering a positive charge to them. The aim of this work was to evaluate factors that influence DNA compaction in cationic nanoemulsions containing stearylamine. The influence of the stearylamine incorporation phase (water or oil), time of complexation, and different incubation temperatures were studied. The complexation rate was assessed by electrophoresis migration on agarose gel 0.7%, and nanoemulsion and lipoplex characterization was done by Dynamic Light Scattering (DLS). The results demonstrate that the best DNA compaction process occurs after 120 min of complexation, at low temperature (4 ± 1 °C), and after incorporation of the cationic lipid into the aqueous phase. Although the zeta potential of lipoplexes was lower than the results found for basic nanoemulsions, the granulometry did not change. Moreover, it was demonstrated that lipoplexes are suitable vehicles for gene delivery. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)