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1.
Arch. Hosp. Vargas ; 38(1/2): 37-9, ene.-jun. 1996. tab
Artigo em Espanhol | LILACS | ID: lil-192496

RESUMO

Se evaluó la sensibilidad in vitro de 178 cepas de levaduras aisladas en la sección de bacteriología del Laboratorio Metropolitano (Policlínica Metropolitana) y en la Unidad de Micología del Hospital Vargas de Caracas, a los siguientes antimicóticos: Anfotericina B, Flucitosina, Ketoconazol, Miconazol, Econazol y Nistatina, en un período de 10 meses (nov.1994-agosto 1995). Para la identificación de las cepas se emplearon métodos manuales bioquímicos y automatizados por sistema ATB Expression, y para la determinación de la sensibilidad se utilizó el sistema ATB Fungus (bioMérieux). De 178 cepas: 83 C. albicans (46,62 por ciento); C. tropicalis 51 (28,65 por ciento); C. glabrata 14 (7,86 por ciento); C. parapsilosis 13 (7,30 por ciento), entre otras. El porcentaje de sensibilidad en general fue de: Anfotericina B 94,38 por ciento, Flucitosina 90,44 por ciento, Nistatina 97,19 por ciento, Ketoconazol 89,88 por ciento, Miconazol 94,94 por ciento y Econazol 85,95 por ciento. Estos resultados nos permiten afirmar que en nuestro estudio se observó una alta sensibilidad in vitro de las levaduras a las diferentes drogas antimicóticas utilizadas; sin embargo, es necesario ampliar estos datos con otros centros y compararlos con otras técnicas de sensibilidad in vitro y con la inclusión de nuevos antimicóticos de uso más reciente como Fluconazol e Itraconazol.


Assuntos
Adolescente , Adulto , Pessoa de Meia-Idade , Humanos , Masculino , Feminino , Antifúngicos/análise , Fluconazol/uso terapêutico , Fungos , Técnicas In Vitro , Itraconazol/uso terapêutico , Micoses , Cebolas/análise , Leveduras/análise , Infecções Bacterianas , Venezuela
2.
Biochemistry ; 29(38): 8998-9006, 1990 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-2271573

RESUMO

Recently, we have designed a series of simplified artificial signal sequences and have shown that a proline residue in the signal sequence plays an important role in the secretion of human lysozyme in yeast, presumably by altering the conformation of the signal sequence [Yamamoto, Y., Taniyama, Y., & Kikuchi, M. (1989) Biochemistry 28, 2728-2732]. To elucidate the conformational requirement of the signal sequence in more detail, functional and nonfunctional signal sequences connected to the N-terminal five residues of mature human lysozyme were chemically synthesized and their conformations in a lipophilic environment [aqueous trifluoroethanol (TFE) or sodium dodecyl sulfate micelles] analyzed by circular dichroism (CD) and 1H nuclear magnetic resonance (NMR) spectroscopy. The helix content of the peptides, including functional (L8, CL10) and nonfunctional (L8PL, L8PG, L8PL2) signal sequences, was estimated from CD spectra to be 40-50% and 60-70%, respectively, indicating that the helical structure is more abundant in the nonfunctional signal sequences. Two-dimensional NMR analyses in 50% TFE/H2O revealed that each peptide adopted a helical conformation throughout the sequence except for a few residues at the N- and C-termini. Furthermore, H-D exchange experiments indicated that the helical structure of the C-terminal region of the functional signal sequences (L8 and CL10) was less stable than that of the nonfunctional signal sequences (L8PL and L8PL2). On the basis of these results, a model was developed in which the functional signal sequence is inserted in the membrane with a helical conformation and the C-terminal helix unraveled in an extended conformational form through an interaction with the signal peptidase.


Assuntos
Sinais Direcionadores de Proteínas/química , Leveduras/análise , Sequência de Aminoácidos , Animais , Galinhas , Dicroísmo Circular , Humanos , Hidrogênio , Espectroscopia de Ressonância Magnética , Micelas , Dados de Sequência Molecular , Muramidase , Conformação Proteica , Dodecilsulfato de Sódio , Solubilidade , Trifluoretanol
3.
Biochemistry ; 29(13): 3389-95, 1990 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-2159335

RESUMO

A method is reported for the synthesis of pyrene-labeled analogues of phosphatidylinositol 4-phosphate (Pyr-PIP) and phosphatidylinositol 4,5-biphosphate (Pyr-PIP2) from sn-2-(pyrenyl-decanoyl)phosphatidylinositol (Pyr-PI) using partially purified PI and PIP kinase preparations. Phosphorylation of Pyr-PI and Pyr-PIP was extensive (more than 50%) provided that the ATP concentration was high and that stabilizing agents such as sucrose and polyethylene glycol were present in the incubation medium. Pyr-PIP and Pyr-PIP2 were isolated by chromatography on immobilized neomycin. The identity of the products was established by thin-layer chromatography, UV-absorption spectroscopy, and spectrofluorometry. The pyrene excimer/monomer fluorescence technique revealed that, in contrast to Pyr-PI, Pyr-PIP and Pyr-PIP2 formed clusters in organic solvents. By use of the same technique for model membranes, it was shown that in phosphatidylcholine bilayers the collision frequency of the three fluorescent phosphoinositides decreased in the order PI greater than PIP greater than PIP2. Addition of Ca2+ at concentrations above 0.1 mM increased the collision frequency of Pyr-PIP2 and, to a much lesser extent, Pyr-PIP; Ca2+ had no effect on Pyr-PI.


Assuntos
Bicamadas Lipídicas , Fosfatidilinositóis , Fosfotransferases , Pirenos , Animais , Encéfalo/enzimologia , Bovinos , Membrana Celular/enzimologia , Fenômenos Químicos , Química , Fluorescência , Fosfatidilcolinas , Fosfatos de Fosfatidilinositol , Solventes , Leveduras/análise
4.
FEBS Lett ; 261(1): 131-4, 1990 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-2155129

RESUMO

Based on the results of the so-called redox-cycling assay it has been claimed that various common foods and beverages as well as mammalian body fluids and tissues contain substantial quantities (microM) of free PQQ [M. Paz et al. (1989) in: PQQ and Quinoproteins (J.A. Jongejan and J.A. Duine, eds.) Kluwer Academic Publishers, Dordrecht, pp. 131-143 and J. Killgore et al. (1989) Science 245, 850-852]. However, by investigating samples from such sources with a biological assay of nM sensitivity, we could not confirm these claims. Analysis of the samples with procedures that proved adequate for the detection of PQQ adducts and conjugates gave equally negative results. To account for the positive response in the redox-cycling assay, as opposed to the negative results obtained by other methods, a search was made for those substances in these samples that caused the false-positive reactions. It was found that a number of commonly occurring biochemicals like ascorbic and dehydroascorbic acid, riboflavin and to a lesser extent pyridoxal phosphate, gave a positive response in the redox-cycling assay. The amounts of these interfering substances that were determined in the samples by independent methods could well explain the response. In separate experiments it was found that the effect of PQQ added to biological samples was obscured over an appreciable range of concentrations. For these reasons it must be concluded that the redox-cycling assay is not suited for the detection of PQQ in these samples. Any claims that are based on the results of this method should be disregarded.


Assuntos
Coenzimas/análise , Análise de Alimentos , Quinolonas/análise , Animais , Reações Falso-Positivas , Métodos , Miocárdio/análise , Oxirredução , Cofator PQQ , Quinolonas/sangue , Quinolonas/urina , Suínos , Leveduras/análise
5.
Proteins ; 8(2): 156-63, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2172962

RESUMO

A common sequence/structural motif pattern has been identified within the steroid/thyroid hormone receptors and other transcriptional activators using a new massively parallel symbolic learning assistant computer system. The pattern appears nearly diagnostic of transcription activation, including relative activation strength, among nuclear and DNA-binding prokaryotic proteins. In cases where mutation/deletion/chimeric studies have identified the activation domain, the pattern matches within that domain. These facts and the nature of the pattern itself strongly support the idea that the patterned domain is directly involved in a protein-protein transcription activation interaction.


Assuntos
Transativadores/química , Sequência de Aminoácidos , Bactérias/análise , Proteínas de Ligação a DNA/química , Dados de Sequência Molecular , Conformação Proteica , Receptores de Superfície Celular/química , Homologia de Sequência do Ácido Nucleico , Vírus/análise , Leveduras/análise
7.
Arch Tierernahr ; 39(11): 963-70, 1989 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-2619554

RESUMO

A method for the fluorimetric determination of benzo(a)pyrene content is presented consisting of classical clean-up steps. The method was applied to microbial biomasses and different feed stuffs. The investigated yeasts grown on carbohydrates keep the limit of 5 ppb benzo(a)-pyrene recommended by the IUPAC. Yeast samples of the VEB Petrolchemisches Kombinat Schwedt grown on petroleum distillate have a constant quality with benzo(a)pyrene contents at 1 ppb. A selection of bacterial biomasses shows also contents less than 5 ppb. The benzo(a)pyrene contents of biomasses cultivated on liquid manure exceed the given limit.


Assuntos
Ração Animal/análise , Benzo(a)pireno/análise , Proteínas na Dieta/análise , Leveduras/análise , Fluorometria
8.
J Nutr ; 119(10): 1357-60, 1989 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2585128

RESUMO

Because previous observations suggest that biotin may be present in vitamin preparations not labeled as containing biotin, we determined the biotin content of several over-the-counter vitamin and nutritional supplements said to contain biotin (group 1) and several in which biotin content was not specified (group 2). Biotin concentration was measured using the 125I-avidin assay which detects total avidin-binding substances. Water extracts were assayed for free biotin and acid hydrolysates were assayed for total biotin. The results of the 125I-avidin assay agreed with the stated biotin content for most vitamin and nutritional supplements in group 1. Biotin was the only avidin-binding substance in the preparations from group 1, based on reversed-phase chromatography. However, some vitamin and nutritional supplements in group 2 contained nutritionally significant amounts of biotin, particularly if the supplement contained liver or yeast extract. Total biotin was significantly higher than free biotin in one supplement; the difference was attributable to release of biotin rather than a biotin analog. We conclude that biotin may be present in some vitamin and nutritional supplements not labeled as containing biotin; biotin intake might be under-estimated if the subject is receiving a nutritional supplement containing extracts of liver or yeast.


Assuntos
Biotina/análise , Alimentos Fortificados/análise , Necessidades Nutricionais , Vitaminas/análise , Ácidos , Cromatografia Líquida de Alta Pressão , Rotulagem de Medicamentos , Rotulagem de Alimentos , Indústria de Processamento de Alimentos , Humanos , Hidrólise , Extratos Hepáticos/análise , Leveduras/análise
9.
Anal Biochem ; 181(2): 227-33, 1989 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2530918

RESUMO

The newly designed equipment for alternating field gel electrophoresis which permits the separation of very large DNA molecules and the simultaneous analysis of up to 35 samples is described. The field alternation is effected by intermittently rotating the submerged agarose gel by optitional angles. The time intervals between changes of position are controlled by a computer program driving a simple switching device which was designed to suit any technique using periodic switching or inversion of the electrical field. Because the electrophoresis unit provides an absolutely homogeneous electrical field, no distortion of migration lanes occurs and the resolution is very good. Moreover, by using a switching time interval gradient an almost perfect linear relationship between migration distances and molecule sizes in the range of about 100-1250 kilobase pairs is observed. In two-dimensional separations, different switching time programs for the first and second dimension allow maximum resolution of selected size ranges. Field inversion gel electrophoresis is possible as well. The performance of the method is demonstrated by comparing the chromosome sizes of different yeast strains.


Assuntos
DNA/isolamento & purificação , Eletroforese em Gel de Ágar/instrumentação , Bacteriófago lambda/análise , Cromossomos Fúngicos , Computadores , DNA Viral/análise , Campos Eletromagnéticos , Eletroforese , Etídio , Indicadores e Reagentes , Temperatura , Leveduras/análise
10.
Rev. microbiol ; 20(3): 278-91, jul.-set. 1989. tab
Artigo em Português | LILACS | ID: lil-79978

RESUMO

O estudo de autodepuraçäo de um córrego sub-tropical, córrego do Agriäo, afluente do Rio Jacaré-Pepira, S. P., que recebe afluentes de resíduos domésticos e pecuários foi efetuado utilizando-se indicadores biológicos: coliformes totais (CT) e fecais (CF), estreptococos fecais (EF), fungos aquáticos e geofungos. O período de estudo abrangeu duas estiagens e um período de chuvas. Foi observada a influência das condiçöes fisiográficas na auto-depuraçäo do curso d'água. A relaçäo CF/EF possibilitou a caracterizaçäo da origem dos despejos e constatou-se que o número de leveduras, (U.F.C./ml), foi bom indicador de poluiçäo de origem fecal, o que näo ocorreu com bolores aquáticos e terrestres


Assuntos
Enterobacteriaceae/imunologia , Enterococcus faecalis/imunologia , Fungos/imunologia , Microbiologia da Água/análise , Poluição da Água , Água Doce/análise , Brasil , Poluentes da Água/análise , Leveduras/análise
11.
Mycoses ; 32(7): 344-8, 1989 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2797049

RESUMO

Protein patterns of Candida species and other yeasts have been studied by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Although differences in patterns occur which tend to separate the species, variability between replicate samples is sometimes high. The method cannot be used for speciation of common yeasts from medical sources.


Assuntos
Candida/análise , Proteínas Fúngicas/análise , Leveduras/análise , Eletroforese em Gel de Poliacrilamida , Humanos
13.
Rev. cuba. aliment. nutr ; 2(2): 269-77, jul.-dic. 1988. tab
Artigo em Espanhol | LILACS | ID: lil-112234

RESUMO

Se evaluó la influencia de la ingestión de Kluyveromyces fragilis en dietas para ratas con 20 y 40 % de la levadura como fuente de proteinas sobre la actividad de las disacaridasas intestinales: lactasa, maltasa, sacarosa y trealasa en 4 niveles sucesivos de ubicación de la microvellosidad intestinal: luminal, membrana, enterocito y actividad total, para lo cual se utilizó una técnica de lavados y homogeneizados en fragmentos de intestinos tomados en la zona del ángulo de Treittz, en un total de 67 ratas agrupadas según la dieta recibida en a) grupo con pienso para roedores, b) grupo con caseina como fuente de proteinas, c)grupo con levadura al 40% durante un período experimental de 90 dias. Al comparar los resultados de las actividades enzimáticas entre los grupos estudiados, no se encontraron diferencias significativas para ninguna de las enzimas analizadas ni en ninguno de los niveles de localización en el enterocito


Assuntos
Ratos , Dissacaridases/análise , Análise de Alimentos , Proteínas na Dieta , Saccharomycetales/análise , Leveduras/análise
14.
Biochim Biophys Acta ; 945(2): 324-34, 1988 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-3191127

RESUMO

The elemental surface composition of eleven microorganisms was determined by X-ray photoelectron spectroscopy. Bacteria could be distinguished from yeasts by higher nitrogen and phosphate concentrations. Overall physico-chemical properties, electrical charge and hydrophobicity, were also investigated: the former by electrophoretic mobility measurements, the latter by contact angle and by hydrophobic interaction chromatography. Phosphate plays the major role in determining the surface electrostatic charge. A correlation is observed between the N/P atomic concentration ratio and the electrostatic charge. In bacteria, hydrophobicity is directly related to concentration of carbon in hydrocarbon form and inversely related to oxygen concentration or to the N/P ratio. For yeasts, a positive correlation is found between hydrophobicity and the N/P ratio, pointing at the role of proteins in determining the hydrophobicity.


Assuntos
Bactérias/análise , Leveduras/análise , Aderência Bacteriana , Adesão Celular , Fenômenos Químicos , Físico-Química , Eletroforese , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Solubilidade , Análise Espectral , Propriedades de Superfície , Água
15.
Biomed Chromatogr ; 2(6): 258-9, 1988 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-3233396

RESUMO

A new method for the determination of bonded selenomethionine in selenium yeast by gas chromatography is established. Bonded selenomethionine is rapidly and precisely determined by measuring CH3SeCN released during the reaction of selenoprotein with CNBr (CNBr-GC method). Conditions for the reaction and chromatography are described. The results of CNBr-GC are compared with those obtained by acid hydrolysis/ion exchange chromatography. This new method has the advantage of being accurate, sensitive and selective.


Assuntos
Selênio/análise , Selenometionina/análise , Leveduras/análise , Cromatografia Gasosa , Brometo de Cianogênio , Indicadores e Reagentes
19.
Arch Biochem Biophys ; 261(2): 458-62, 1988 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-3355160

RESUMO

The crude extract prepared from Glycyrrhiza echinata cells treated with yeast extract catalyzed the formation of liquiritigenin (5-deoxyflavanone) and isoliquiritigenin (6'-deoxychalcone) in addition to naringenin (5-hydroxyflavanone) when incubated with 4-coumaroyl-CoA and malonyl-CoA in the presence of high concentrations (0.1 mM or higher) of NADPH. Incubation without NADPH, or with low concentrations (0.01 mM or lower), gave only naringenin as a reaction product. With NADH (1 mM), the major product was naringenin accompanied by a small quantity of liquiritigenin. The initial product of the assay with 1 mM NADPH was isoliquiritigenin, indicating a reaction catalyzed by 6'-deoxychalcone synthase (DOCS). Subsequent formation of liquiritigenin was attributed to the presence of chalcone isomerase in the crude extract. The results constitute the first demonstration in vitro of DOCS activity which, in G. echinata cells and other leguminous plants, is involved in the biosynthesis of retrochalcone and 5-deoxyisoflavonoid-derived phytoalexins.


Assuntos
Aciltransferases/biossíntese , Glycyrrhiza/enzimologia , Plantas Medicinais , Sistema Livre de Células , Indução Enzimática/efeitos dos fármacos , Alcaloides de Pirrolizidina/biossíntese , Leveduras/análise
20.
Antonie Van Leeuwenhoek ; 54(4): 367-75, 1988.
Artigo em Inglês | MEDLINE | ID: mdl-3178190

RESUMO

Total glutathione content, glutathione peroxidase, glutathione transferase and glutathione reductase activities have been measured in 12 species of yeasts. All the strains tested contained glutathione, though in different amounts, as well as the above mentioned enzymes. To discriminate between the selenium-dependent and the selenium-independent form, glutathione peroxidase activity has been measured with both H2O2 and cumene hydroperoxide. Rhodotorula glutinis appeared to be the only strain in which the selenium-dependent form was not found, but this yeast exhibited the highest level of selenium-independent glutathione peroxide activity as compared to the other strains.


Assuntos
Glutationa Peroxidase/análise , Glutationa Redutase/análise , Glutationa Transferase/análise , Glutationa/análise , Leveduras/análise
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