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Texto completo SciELO Brasil
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Id: biblio-1249176
Autor: Gonçalves, Melissa Marques; Carneiro, Jaqueline; Justus, Barbara; Espinoza, Joel Toribio; Budel, Jane Manfron; Farago, Paulo Vitor; Paula, Josiane Padilha de.
Título: Preparation and characterization of a novel antimicrobial film dressing for wound healing application
Fonte: Braz. J. Pharm. Sci. (Online);56:e18784, 2020. tab, graf.
Idioma: en.
Resumo: Antibacterial activity and good mechanical properties are some of the characteristics required for an appropriate film dressing. A novel polymer blend was developed for wound healing application. Twenty-four formulations using the polymers chitosan, poly(vinyl alcohol) and/or É›-Polylysine and the plasticizer glycerol were designed using factorial design and then the films were prepared by the casting/solvent evaporation method. Seventeen films were obtained among the twenty-four proposed formulations that were characterized by Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared Spectroscopy (FTIR). Mechanical properties, such as tensile strength (σ), elongation at break (É›) and Young's modulus (Y) as well as antibacterial properties were determined. The best candidate was then further analyzed with regard to porosity, Water Vapor Transmission Rate (WVTR), swelling and cytotoxicity experiments. The results showed a film with semi-occlusive characteristics, good mechanical properties and no toxic. Incorporation of É›-Polylysine increased antibacterial activity against gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria
Descritores: Bandagens
Cicatrização/efeitos dos fármacos
Microscopia Eletrônica de Varredura/métodos
Espectroscopia de Infravermelho com Transformada de Fourier
Responsável: BR40.1 - DBD - Divisão de Biblioteca e Documentacão do Conjunto das Químicas

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Texto completo SciELO Brasil
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Id: biblio-1041540
Autor: Holanda, Vanusa Gonçalves; Barbosa, Diogo Brunno e Silva; Pereira, Leudimar Aires; Soares, Maria Regiane Araujo.
Título: Use of Kisser glycerol gelatin to prepare microscope slides of Phlebotomine sandflies (Diptera: Psychodidae)
Fonte: Rev. Soc. Bras. Med. Trop;52:e20180072, 2019. tab, graf.
Idioma: en.
Projeto: Fundação de Amparo à Pesquisa do Estado do Piauí.
Resumo: Abstract INTRODUCTION: Appropriate preservation of specimens is important for taxonomic identification. In sandfly research, various methods have been used for slide preparation; however, high cost, low commercial availability, and associated hazards make their use impossible in some studies. Therefore, the efficacy of Kisser glycerol gelatin for sandfly slide preparation was tested. METHODS: Kisser glycerol gelatin, as a substitute for Canada balsam and Berlese's fluid, was used for mounting sandflies. RESULTS: Forty-two mounted specimens were created and maintained even after 14 months. CONCLUSIONS: Use of Kisser glycerol gelatin is simple and efficient for preparing microscope slides of sandflies.
Descritores: Psychodidae
Manejo de Espécimes/métodos
Insetos Vetores
Limites: Animais
Responsável: BR1.1 - BIREME

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Texto completo SciELO Chile
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Id: biblio-950822
Autor: Aftab, Usman; Zechel, David L; Sajid, Imran.
Título: Antitumor compounds from Streptomyces sp. KML-2, isolated from Khewra salt mines, Pakistan
Fonte: Biol. Res;48:1-10, 2015. ilus, graf, tab.
Idioma: en.
Resumo: BACKGROUND: Actinomycetes are gram positive bacteria with high G + C content in their DNA and are capable of producing variety of secondary metabolites. Many of these metabolites possess different biological activities and have the potential to be developed as therapeutic agents. The aim of the present study was to screen actinomycetes inhabiting halophilic environment such as Khewra salt mines present in Pakistan for cytotoxic and antitumor compounds. RESULTS: An actiomycetes strain designated as Streptomyces sp. KML-2 was isolated from a saline soil of Khewra salt mines, Pakistan. The strain Streptomyces sp. KML-2 showed 84 % cytotoxic activity against larvae of Artemiasalina. In the screening phase, the strain exhibited significant antitumor activity with IC50 values of 12, 48 and 56 µg/ml against Hela, MDBK and Vero cell lines, respectively. After that extract from 20 l fermentation was used to purify secondary metabolites by several chromatographic techniques. Structure elucidation of isolated compounds revealed that it is highly stable producer of Chromomycin SA (1) and 1-(1H-indol-3-yl)-propane-1,2,3-triol (2). Both of the isolated compounds showed significant antitumor activity against Hela and MCF-7 cancer cell lines (IC50 values 8.9 and 7.8 µg/ml against Hela; 12.6 and 0.97 µg/ml against MCF-7, respectively). The 16S rRNA gene sequence (1437 bp) of the strain confirm its identity (99 %) with Streptomyces griseus. CONCLUSIONS: From this research work we were successful in isolating two potent antitumor compounds, Chromomycin SA and 1-(1H-indol-3-yl)-propane-1,2,3-triol from Streptomyces KML-2 strain, isolated from Khewra salt mine. As such this is the second report which confirms that S. griseus can produce Chromomycin SA without introducing any mutagenesis in its biosynthesizing gene cluster and isolated indole derivative is being reported first time from any member of actinomycetes group with having novel antitumor activity against Hela and MCF-7 cells Nucleotide sequences: Nucleotide sequence data reported are available in the GenBank database under the accession number: GenBank KJ009562.
Descritores: Microbiologia do Solo
Artemia/efeitos dos fármacos
Streptomyces/isolamento & purificação
Streptomyces griseus/classificação
Sais de Tetrazólio
Células Vero
RNA Ribossômico 16S/genética
Células HeLa
Microscopia Eletrônica de Varredura
Linhagem Celular
Chlorocebus aethiops
Análise de Sequência de RNA
Concentração Inibidora 50
Células MCF-7
Glicerol/análogos & derivados
Larva/efeitos dos fármacos
Antibacterianos/isolamento & purificação
Antineoplásicos/isolamento & purificação
Limites: Humanos
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: CL1.1 - Biblioteca Central

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Texto completo SciELO Brasil
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Id: biblio-1156206
Autor: Caetano, Edie Benedito; Vieira, Luiz Angelo; Sabongi Neto, João José; Caetano, Maurício Benedito Ferreira; Picin, Celis Piovesan; Silva Júnior, Luiz Claudio Nascimento da.
Título: Anatomical Study of the Motor Branches of the Radial Nerve in the Forearm / Estudo anatômico dos ramos motores do nervo radial no antebraço
Fonte: Rev. bras. ortop;55(6):764-770, Nov.-Dec. 2020. tab, graf.
Idioma: en.
Resumo: Abstract Objective To analyze the anatomical variations of the motor branches of the radial nerve in the elbow region. The origin, course, length, branches, motor points and relationships with neighboring structures were evaluated. Materials and Methods Thirty limbs from15 adult cadavers were dissected and prepared by intra-arterial injection of a 10% glycerin and formaldehyde solution. Results The first branch of the radial nerve in the forearm went to the brachioradialis muscle (BR), originating proximally to the division of the radial nerve into superficial branch of the radial nerve (SBRN) and posterior interosseous nerve (PIN) in all limbs. The branches to the extensor carpi radialis longus muscle (ECRL) detached from the proximal radial nerve to its division into 26 limbs, in 2, at the dividing points, in other 2, from the PIN. In six limbs, the branches to the BR and ECRL muscles originated from a common trunk. We identified the origin of the branch to the extensor carpi radialis brevis muscle (ECRB) in the PIN in 14 limbs, in the SBRN in 12, and in the radial nerve in only 4. The branch to the supinator muscle originated from the PIN in all limbs. Conclusion Knowledge of the anatomy of the motor branches of the radial nerve is important when performing surgical procedures in the region (such as the approach of the proximal third and the head of the radius, release of compressive syndromes of the posterior interosseous nerve and radial tunnel, and distal nerve transfers) in order to understand the order of recovery of muscle function after a nerve injury.

Resumo Objetivo Analisar as variações anatômicas dos ramos motores do nervo radial na região do cotovelo. Foram avaliadas a origem, curso, comprimento, ramificações, pontos motores e relações com estruturas vizinhas. Materiais e Métodos Foram dissecados 30 membros de 15 cadáveres adultos, preparados por injeção intra-arterial de uma solução de glicerina e formol a 10%. Resultados O primeiro ramo do nervo radial no antebraço foi para o músculo braquiorradial (BR), que se origina proximalmente à divisão do nervo radial em ramo superficial do nervo radial (RSNR) e nervo interósseo posterior (NIP) em todos os membros. Os ramos para o músculo extensor radial longo do carpo (ERLC) se desprenderam do nervo radial proximalmente à sua divisão em 26 membros, em 2, nos pontos de divisão, em outros 2, do NIP. Em seis, os ramos para os músculos BR e ERLC originavam-se de um tronco comum. Identificamos a origem do ramo para o músculo extensor radial curto do carpo (ERCC) no NIP em 14 membros, no RSNR em 12, e no nervo radial em apenas 4. O ramo para o músculo supinador originou-se do NIP em todos os membros. Conclusão O conhecimento da anatomia dos ramos motores do nervo radial é importante quando se realizam procedimentos cirúrgicos na região, como a abordagem do terço proximal e da cabeça do rádio, a liberação das síndromes compressivas do nervo interósseo posterior e do túnel radial, as transferências nervosas distais, e para entender a ordem de recuperação da função muscular após uma lesão nervosa.
Descritores: Nervo Radial
Rádio (Anatomia)
Procedimentos Cirúrgicos Operatórios
Transferência de Nervo
Marcação In Situ das Extremidades Cortadas
Traumatismos do Antebraço
Injeções Intra-Arteriais
Responsável: BR26.1 - Biblioteca Central

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Id: biblio-1051342
Autor: Pele, Milagre A; Rubio Ribeaux, Daylin; Rodrigues Vieira, Edson; Souza, Adriana F; Luna, Marcos A C; Montero Rodríguez, Dayana; Andrade, Rosileide F S; Sales Alviano, Daniela; Sales Alviano, Celuta; Barreto-Bergter, Eliana; Santiago, André L C M A; Campos-Takaki, Galba M.
Título: Conversion of renewable substrates for biosurfactant production by Rhizopus arrhizus UCP 1607 and enhancing the removal of diesel oil from marine soil
Fonte: Electron. j. biotechnol;38:40-48, Mar. 2019. tab, graf, ilus.
Idioma: en.
Projeto: CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico); . FACEPE (Fundação de Amparo à Ciência e Tecnologia de Pernambuco).
Resumo: BACKGROUND: The use of agro-industrial wastes to produce high value-added biomolecules such as biosurfactants is a promising approach for lowering the total costs of production. This study aimed to produce biosurfactants using Rhizopus arrhizus UCP 1607, with crude glycerol (CG) and corn steep liquor (CSL) as substrates. In addition, the biomolecule was characterized, and its efficiency in removing petroderivatives from marine soil was investigated. RESULTS: A 22 factorial design was applied, and the best condition for producing the biosurfactant was determined in assay 4 (3% CG and 5% CSL). The biosurfactant reduced the surface tension of water from 72 to 28.8 mN/m and produced a yield of 1.74 g/L. The preliminary biochemical characterization showed that the biosurfactant consisted of proteins (38.0%), carbohydrates (35.4%), and lipids (5.5%). The compounds presented an anionic character, nontoxicity, and great stability for all conditions tested. The biomolecule displayed great ability in dispersing hydrophobic substrates in water, thereby resulting in 53.4 cm2 ODA. The best efficiency of the biosurfactant in removing the pollutant diesel oil from marine soil was 79.4%. CONCLUSIONS: This study demonstrated the ability of R. arrhizus UCP1607 to produce a low-cost biosurfactant characterized as a glycoprotein and its potential use in the bioremediation of the hydrophobic diesel oil pollutant in marine soil
Descritores: Rhizopus/metabolismo
Tensão Superficial
Biodegradação Ambiental
Ambiente Marinho
Zea mays
Interações Hidrofóbicas e Hidrofílicas
Resíduos Industriais
Responsável: CL1.1 - Biblioteca Central

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Id: lil-767262
Autor: Silva, JFM; Malta, CM; Peluzzio, JM; Faraco, A; Prado, G; Madeira, JEGC; Silva, MO; Nicoli, JR; Pimenta, RS.
Título: Utilização de um filme de glicerol para o controle da produção de aflatoxina por Aspergillus parasiticus em amendoim / Use of glycerol coating to control aflatoxin production by Aspergillus parasiticus in peanut grains
Fonte: Rev. ciênc. farm. básica apl;36(2), jun. 2015. ilus, tab.
Idioma: en.
Resumo: Peanut grains are very susceptible to aflatoxin contamination. Aflatoxins are toxic metabolites produced by Aspergillus flavus, A. nomius and A. parasiticus. The aflatoxin B1 is most frequently found in peanuts, posing a high toxicological risk due to its carcinogenic, teratogenic and mutagenic properties. Alternative methods to fungicides can be used to protect grains. GRAS (Generally Regarded As Safe) substances can be an interesting option to avoid contamination, specially glycerol. In the present work, the ability of glycerol films to prevent aflatoxin production by A. parasiticus in peanuts was evaluated. Glycerol was established in two different ways: by immersion and aspersion. Aspersion was more efficient in reducing aflatoxin production (86.3%) than was the immersion process (66.9%) (P < 0.05). At the same time, a progressive reduction in A. parasiticus colony diameters was observed (from 38.6 ± 0.9 to 34.4 ± 1.7 mm) when the fungus was grown on GYEP medium supplemented with glycerol (0 to 5%). However, varying concentrations did not influence the production of spores, colonies, conidiophores or spore condition. Peanuts coated with 5% glycerol (by immersion or aspersion) had improved characteristics, with a cleaner and more shiny appearance, which can make the resulting product more acceptable to the population. In conclusion, the reduction of aflatoxin production in peanut grains with glycerol, particularly by aspersion, was satisfactory, and this GRAS substance shows promising potential to be used to prevent mycotoxin contamination in grains.(AU)

O amendoim é muito suscetível à contaminação por aflatoxinas, que são metabólitos tóxicos produzidos por Aspergillus flavus, A. parasiticus e A. nomius. A aflatoxina B1 é a mais frequentemente encontrada nos amendoins e apresenta risco toxicológico devido às suas propriedades carcinogênicas, teratogênicas e mutagênicas. Entre os métodos de prevenção da contaminação, o uso de substâncias GRAS (substâncias geralmente consideradas seguras) pode apresentar grande potencial de exploração, especialmente o glicerol. No presente trabalho, foi avaliada a capacidade de filmes de glicerol para o controle da produção de aflatoxinas em amendoins. O glicerol foi inoculado por imersão ou aspersão, sendo a aspersão mais eficiente na redução da produção de aflatoxina (86,3%) que a imersão (66,9%) (P < 0,05). Ao mesmo tempo, foi observada uma redução nos diâmetros das colônias de A. parasiticus (38,6 ± 0,9 para 34,4 ± 1,7 mm) quando cultivado em meio GYEP suplementado com glicerol (0 a 5%). Apesar disto, diferentes concentrações não influenciaram a produção ou morfologia dos esporos e conidióforos. Amendoins revestidos com 5% de glicerol apresentaram características interessantes, tais com: maior brilho e coloração mais intensa, o que pode tornar o produto mais atraente para o consumidor. Em conclusão, a redução da produção de aflatoxinas em amendoim pelo glicerol, principalmente por aspersão foi satisfatória. Sendo assim, esta substância apresenta um potencial promissor para utilização para a prevenção da contaminação do amendoim por aflatoxinas.(AU)
Descritores: Arachis
Conservação de Alimentos/métodos
Responsável: BR33.1 - Divisão Técnica de Biblioteca e Documentação

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Id: biblio-1104226
Autor: Pavlov, Sergey; Babenko, Nataliia; Kumetchko, Marina; Litvinova, Olga; Semko, Natalia; Pavlova, Olga.
Título: Intercellular mediators in bone remodeling regulation in the experimental renal pathology / Mediadores intercelulares de la regulación de la remodelación ósea en un modelo experimental de patología renal
Fonte: Actual. osteol;15(3):180-191, Sept-Dic. 2019. ilus.
Idioma: en.
Resumo: Bone metabolism disorders are characterized by an imbalance of bone resorption and formation in the bone remodeling process. Glucocorticoids that are used to treat kidney diseases exacerbate these disorders. P-selectin and galectin-3 are molecules involved in the sclerotic process in kidney, whereas bone resorption is regulated by the interaction between the nuclear factor activator kappa b receptor (RANK), its ligand (RANKL) and the RANKL decoy receptor osteoprotegerin (OPG). The aim of this study was to investigate the cellular and molecular mechanisms of disruption of bone remodeling regulation processes, reflected by intercellular mediators (RANKL, OPG, P-selectin and galectin-3) in chronic kidney disease experimental model treated with glucocorticoids. Rats were divided into four groups of 10 animals each. The first group, the control group, included intact animals. The second group consisted of rats with impaired bone remodeling resulting from chronic kidney disease (experimental group (CKD). The third group was a group of animals with impaired bone remodeling due to exposure to glucocorticoids (experimental group (GCs)). The fourth group consisted of rats with impaired bone remodeling in chronic kidney disease, followed by exposure to glucocorticoids (experimental group (CKD + GCs)). The effects of CKD and glucocorticoid were evaluated biochemically, histologically and by measuring bone density. An enzymelinked immunoassay was used to measure intercellular mediator levels in the serum. The bone density in the experimental groups was reduced compared to the control group. RANKL levels in animals of three experimental groups were higher than in intact animals. Serum levels of OPG were higher in CKD and GCs groups than in intact animals. At the same time, in the animals' blood serum of the CKD + GCs group, the levels of OPG were lower, than those in animals from the control group. The levels of galectin-3 in the serum of the experimental groups GCs and CKD + GCs were lower than in intact animals. The serum levels of galectin-3 in animals of the CKD group were higher than those in animals from the control group. The levels of P-selectin were lower in the serum of the GCs group than in intact animals. At the same time, the levels of P-selectin were higher in the CKD and CKD + GCs groups, than those in animals from the control group. In conclusion, the study of the complex system of bone remodeling regulation, which includes many factors and their interactions, may lead to the development of new methods for treating patients with chronic kidney disease in order to prevent osteoporosis in the future. (AU)

Las enfermedades metabólicas óseas se caracterizan por un desequilibrio en el proceso de remodelación ósea en los que participan mediadores tales como receptor del activador del factor nuclear- kappa- b (RANK), su ligando (RANKL) y la osteoprotegerina (OPG). Los glucocorticoides, recuentemente empleados en el tratamiento de la enfermedad renal crónica, exacerban este desequilibrio. En la enfermedad esclerótica renal, las moléculas de adhesión celular P-selectina and galectina-3 tienen un rol fundamental. El objetivo de esta trabajo fue estudiar las alteraciones en los mediadores de la remodelación ósea (RANKL, OPG, P-selectina and galectina-3) en un modelo de enfermedad renal crónica con tratamiento glucocorticoideo. Ratas Wistar hembras fueron divididos en 4 grupos: control (C); enfermedad renal crónica con afección de la remodelación ósea (ERC); animales con afección de la remodelación ósea expuestos a glucocorticoides (GC); enfermedad renal crónica con afección de la remodelación ósea tratados con glucocorticoides (ERC+GC). Los efectos de la ERC y los GC fueron evaluados bioquímicamente, histológicamente y por medición de la densidad ósea. RANKL, OPG, Pselectina and galectina-3 se cuantificaron en muestras de sangre venosa empleando enzimoinmuno análisis. En los 3 grupos experimentales la densidad ósea se evidenció reducida y los niveles séricos de RANKL elevados respecto al grupo control. Los niveles de OPG en los grupos ERC y GC fueron superiores mientras que en el grupo ERC+GC menores respecto a los animales controles. Galectina 3 plasmática en GC y ERC+GC se encontró reducida y aumentada en los animales ERC, en comparación con los animales controles. La concentración sérica de P-selectina sérica fue mayor en los grupos ERC y ERC+GC, y menor en los animales GC respecto a los niveles plasmáticos de los animales intactos. El avance del conocimiento sobre la regulación de la remodelación ósea a través de la interacción de mediadores sistémicos, en un futuro, puede conducir al desarrollo de nuevas estrategias terapéuticas para la prevención de la osteoporosis en pacientes con enfermedad renal crónica. (AU)
Descritores: Distúrbio Mineral e Ósseo na Doença Renal Crônica/induzido quimicamente
Remodelação Óssea/efeitos dos fármacos
-Osteoporose/prevenção & controle
Doenças Ósseas Metabólicas/diagnóstico
Dexametasona/administração & dosagem
Densidade Óssea/efeitos dos fármacos
Clorofórmio/uso terapêutico
Ratos Wistar
Selectina-P/efeitos dos fármacos
Galectina 3/efeitos dos fármacos
Galectina 3/sangue
Ligante RANK/efeitos dos fármacos
Ligante RANK/sangue
Osteoprotegerina/efeitos dos fármacos
Glucocorticoides/efeitos adversos
Glicerol/administração & dosagem
Nefropatias/tratamento farmacológico
Limites: Animais
Tipo de Publ: Ensaio Clínico Controlado Aleatório Veterinário
Responsável: AR2.1 - Biblioteca Central

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Texto completo SciELO Brasil
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Id: biblio-886920
Título: Cryopreservation of banana's cv Grand Naine in vitro rhizomes
Fonte: An. acad. bras. ciênc;90(1):495-507, Mar. 2018. tab, graf.
Idioma: en.
Resumo: ABSTRACT The preservation of banana genetic material is usually performed through seedlings. However, most banana cultivars do not produce seed and are propagated vegetatively. Therefore, cryopreservation is a feasible technique that allows the preservation of banana genotypes indefinitely. For the success of cryopreservation protocols, the selection of cryoprotectants and pre-freezing techniques are important factor. Therefore, the objective of this study was to verify the effects of different cryoprotectants with and without 1% phloroglucinol and pre-cooling periods on the development of a protocol for cryopreservation of in vitro rhizomes ofMusa accuminata(AAA) cv Grand Naine banana. The addition of 1% phloroglucinol to the cryoprotective solutions, such as PVS2 enhanced recovery of cryopreserved banana rhizomes. In addition, pre-cooling of explants in ice for 3 hours in PVS2 + 1% of phloroglucinol allowed efficient cryopreservation of banana rhizomes, followed by successful recovery and regeneration of in vitro shoots of banana cv Grand Naine.
Descritores: Floroglucinol/farmacologia
-Valores de Referência
Fatores de Tempo
Reprodutibilidade dos Testes
Brotos de Planta/efeitos dos fármacos
Brotos de Planta/fisiologia
Musa/efeitos dos fármacos
Rizoma/efeitos dos fármacos
Tipo de Publ: Estudo de Avaliação
Responsável: BR1.1 - BIREME

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Id: lil-499688
Autor: Guija Poma, Emilio; Arauco, Fernando; Soberón, Mercedes; Haak Mares, Hielke.
Título: Efecto del glicerol sobre la catálisis por fosfatasa ácida de bajo peso molecular de hígado de alpaca (lama pacos) / Effect of glycerol on catalysis by low molecular weight acid phosphatase from alpaca liver (lama pacos)
Fonte: An. Fac. Med. (Perú);68(4):307-313, oct.-dic. 2007. graf.
Idioma: es.
Resumo: Objetivo: Determinar el efecto del glicerol sobre la hidrólisis del p-nitrofenil fosfato a pH 5,0 por fosfatasa ácida de bajo peso molecular de hígado de alpaca. Diseño: Estudio analítico experimental. Lugar: Centro de Investigación de Bioquímica y Nutrición, Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Materiales: Se utilizó los reactivos químicos p-nitrofenil fosfato sal disódica, ácido acético glacial, glicerol, ácido tricloroacético, ácido sulfúrico, molibdato de amonio, ácido ascórbico, sulfato de amonio, sephadex G-75 (45-120), sulfoetil sephadex C-50 y etilendiaminotetraacético (EDTA). Métodos: Se determinó los parámetros cinéticos Km y Vmax utilizando como sustrato el p-nitrofenil fosfato, en presencia de concentraciones variables de glicerol. Así mismo, se determinó la velocidad de liberación de los productos de la reacción en función de la concentración de dicho nucleófilo. Principales medidas de resultados: Efecto del glicerol sobre la hidrólisis del p-nitrofenil fosfato. Resultados: El glicerol en concentraciones comprendidas entre 1,16 y 3,49 M incrementó linealmente la liberación del p-nitrofenol; en cambio, la formación del fosfato inorgánico -el segundo producto liberado- no se modificó. Así mismo, los valores de Km y Vmax se incrementaron linealmente dependientes de las concentraciones de glicerol, en un rango comprendido entre 0,58 y 2,32 M. Conclusiones: Un análisis de las modificaciones que ejerce el glicerol sobre los valores de Km y Vmax y la velocidad de liberación de los productos de la reacción permite sugerir un modelo en el que la fosfatasa ácida de bajo peso molecular de hígado de alpaca cataliza la hidrólisis de fosfomonoésteres a través de un mecanismo uni biordenado, con la formación de un complejo enzima-fosfato, que sería escindido por agua o un nucleófilo, como el glicerol; en este modelo a k2 le corresponde un valor mucho mayor que k3 y k4 N.

Objective: To determine the effect of glycerol on hydrolysis of p-nitrophenyl phosphate at pH 5,0 by low molecular weight acid phosphatase from alpaca liver. Design: Experimental analytical study. Setting: Biochemistry and Nutrition Research Center, Faculty of Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru. Materials: Disodic p-nitrophenyl phosphate salt, glacial acetic acid, glycerol, tricloroacetic acid, sulfuric acid, ammonium molibdate, ascorbic acid, ammonium sulphate, sephadex G 75 (45-120), sulpho ethyl sephadex C-50 and ethylene diaminotetraacetic (EDTA) chemical reactives. Methods: Both Km and Vmax kinetic parameters were determined with p-nitrophenyl phosphate as substrate in presence of different concentrations of glycerol. The rate of formation of products was determined as a function of the concentration of such nucleophile. Main outcome measures: Glycerol effect on p-nitrophenyl phosphate hydrolysis. Results: Glycerol linearly increased pnitrophenol release at concentrations between 1,16 and 3,49M. Instead, inorganic phosphate formation, the second product, was not modified. Also, Km and Vmax values increased linearly between 0,58 and 2,32 M depending on glycerol concentrations. Conclusions: Analysis of modifications induced by glycerol on Km and Vmax values as well as on liberation velocity of the reaction products suggests a model in which low molecular weight acid phosphatase isolated from alpaca liver catalyses phosphomonoesters hydrolysis through an uni biordered mechanism, with formation of an enzyme phosphate complex that will be splitted by water or a nucleophile such a glycerol; in this model, k2 corresponds to a much higher value than k3 or k4 N.
Descritores: Catálise
Fosfatase Ácida
-Epidemiologia Experimental
Responsável: PE1.1 - Oficina Universitária de Biblioteca

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Texto completo SciELO Brasil
Raw, Isaias
Texto completo
Id: lil-402620
Autor: Leal, Maria Betania Batista; Baruque-Ramos, Júlia; Hiss, Haroldo; Paz, Marcelo Fossa da; Sakai, Maria Cristina; Vassoler, Umbelina Macedo; Arauz, Luciana Juncioni de; Raw, Isaías.
Título: Influence of initial L-asparagine and glycerol concentrations on the batch growth kinetics of Mycobacterium bovis BCG
Fonte: Braz. j. microbiol;35(4):337-344, Oct.-Dec. 2004. tab, graf.
Idioma: en.
Resumo: Estudou-se a influência das concentrações iniciais, no meio de Sauton, de asparagina e glicerol sobre as produtividades, expressas em unidades formadoras de colônias e biomassa microbiana, referentes aos cultivos submersos do Mycobacterium bovis, em biorreator de 20 mL. As concentrações iniciais de 2,27 e 25 mL/L de asparagina e glicerol, respectivamente, conduziram à maior produtividade, em unidades formadoras de colônias, a saber 2,7.106 colônias/mg.dia. Por outro lado, as concentrações de 4,54 e 25 mL/L dos mesmos componentes, corresponderam à melhor produtividade em biomassa, a saber: 2,5 g/dia. Através das análises dos consumos relativos de asparagina e glicerol (50 e 26 per center respectivamente), verificou-se também que as concentrações destes componentes podem ser reduzidas na composição original do meio de Sauton, com o objetivo de obter uma produção otimizada de vacina BCG em bioreator.
Descritores: Asparagina
Vacina BCG
Mycobacterium bovis
Técnicas In Vitro
-Meios de Cultura
Tipo de Publ: Revisão de Integridade Científica
Estudo Comparativo
Responsável: BR32.1 - Serviço de Biblioteca e Informação Biomédica

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