Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Mais filtros










Filtros aplicados
Base de dados
Intervalo de ano de publicação
1.
Electron. j. biotechnol ; 40: 40-44, July. 2019. tab, ilus
Artigo em Inglês | LILACS | ID: biblio-1053231

RESUMO

Background: The study of plant-associated microorganisms is very important in the discovery and development of bioactive compounds. Pseudomonas is a diverse genus of Gammaproteobacteria comprising more than 60 species capable of establishing themselves in many habitats, which include leaves and stems of many plants. There are reports of metabolites with diverse biological activity obtained from bacteria of this genus, and some of the metabolites have shown cytotoxic activity against cancer cell lines. Because of the high incidence of cancer, research in recent years has focused on obtaining new sources of active compounds that exhibit interesting pharmacodynamic and pharmacokinetic properties that lead to the development of new therapeutic agents. Results: A bacterial strain was isolated from tumors located in the stem of Pinus patula, and it was identified as Pseudomonas cedrina. Extracts from biomass and broth of P. cedrina were obtained with chloroform:methanol (1:1). Only biomass extracts exhibited antiproliferative activity against human tumor cell lines of cervix (HeLa), lung (A-549), and breast (HBL-100). In addition, a biomass extract from P. cedrina was fractioned by silica gel column chromatography and two diketopiperazines were isolated: cyclo-(L-Prolyl-L-Valine) and cyclo-(L-Leucyl-L-Proline). Conclusions: This is the first report on the association of P. cedrina with the stems of P. patula in Mexico and the antiproliferative activity of extracts from this species of bacteria against human solid tumor cell lines.


Assuntos
Pseudomonas/química , Pinus/microbiologia , Linhagem Celular Tumoral/efeitos dos fármacos , Antineoplásicos/farmacologia , Plantas/microbiologia , Simbiose , Biomassa , Gammaproteobacteria/química , Proliferação de Células/efeitos dos fármacos
2.
Braz. j. microbiol ; 46(1): 29-39, 05/2015. tab, graf
Artigo em Inglês | LILACS | ID: lil-748236

RESUMO

Awareness on antioxidants and its significance in human healthcare has increased many folds in recent time. Increased demand requisite on welcoming newer and alternative resources for natural antioxidants. Seaweed associated pigmented bacteria screened for its antioxidant potentials reveals 55.5% of the organisms were able to synthesize antioxidant compounds. DPPH assay showed 20% of the organisms to reach a antioxidant zone of 1 cm and 8.3% of the strains more than 3 cm. Pseudomonas koreensis (JX915782) a Sargassum associated yellowish brown pigmented bacteria have better activity than known commercial antioxidant butylated hydroxytoluene (BHT) against DPPH scavenging. Serratia rubidaea (JX915783), an associate of Ulva sp. and Pseudomonas argentinensis (JX915781) an epiphyte of Chaetomorpha media, were also contributed significantly towards ABTS (7.2% ± 0.03 to 15.2 ± 0.09%; 1.8% ± 0.01 to 15.7 ± 0.22%) and FRAP (1.81 ± 0.01 to 9.35 ± 0.98; 7.97 ± 0.12 to 18.70 ± 1.84 μg/mL of AsA Eq.) respectively. 16S rRNA gene sequence analysis revealed bacteria that have higher antioxidant activity belongs to a bacterial class Gammaproteobacteria. Statistical analysis of phenolic contents in relation with other parameters like DPPH, ABTS, reducing power and FRAP are well correlated (p < 0.05). Results obtained from the current study inferred that the seaweed associated pigmented bacteria have enormous potential on antioxidant compounds and need to be extracted in a larger way for clinical applications.


Assuntos
Antioxidantes/metabolismo , Organismos Aquáticos/classificação , Organismos Aquáticos/metabolismo , Gammaproteobacteria/classificação , Gammaproteobacteria/metabolismo , Alga Marinha/microbiologia , Organismos Aquáticos/genética , Organismos Aquáticos/isolamento & purificação , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Gammaproteobacteria/genética , Gammaproteobacteria/isolamento & purificação , Dados de Sequência Molecular , Pigmentos Biológicos/metabolismo , /genética , Análise de Sequência de DNA
3.
São Paulo; s.n; 2014. 172 p. graf.
Tese em Português | LILACS | ID: lil-716093

RESUMO

O reconhecimento da resistência antimicrobiana como um fenômeno emergente em saúde pública, tem constituído um problema em nível mundial. O abuso na utilização de antibióticos na medicina humana e veterinária, e na agricultura, tem originado incremento na diversidade de micro-organismos resistentes, refletindo em falha terapêutica. Os mecanismos de resistência a antibióticos em micro-organismos são mediados principalmente por genes adquiridos de DNA exógeno. A dinâmica da transferência horizontal é realizada por meio de elementos genéticos móveis que carregam genes de resistência. A ampla distribuição deste tipo de estruturas, como o elemento SXT, isolado inicialmente em V. cholerae, tem contribuído para a disseminação de complexos específicos clonais em determinadas áreas geográficas. Este estudo pioneiro no Brasil pesquisou a presença de elementos SXT, em espécies bacterianas do grupo das gama proteobactérias em espécies ambientais, determinou suas características estruturais e funcionais, incluindo genes de resistência a antibióticos, bem como a sensibilidade aos antibióticos dentre os isolados bacterianos que os abrigam. O resultado foi a classificação de 43 elementos SXT obtidos no Brasil, através da comparação com aqueles descritos na literatura. Dentre os elementos SXT obtidos, quatro são albergados por Morganella morganii, fato inédito na literatura. O conhecimento da evolução bacteriana constitui importante ferramenta para estabelecer estratégias eficazes de controle e tratamento de infecções, sem aumentar a pressão seletiva sobre os micro-organismos, bem como instrumento preciso e de grande importância para subsidiar estudos epidemiológicos.


Recognition of antimicrobial resistance as an emerging phenomenon in public health has been a problem worldwide. The abuse in the use of antibiotics in human and veterinary medicine, and agriculture, has caused an increase in the diversity of resistant microorganisms, reflecting in treatment failure. The mechanisms of antibiotic resistance in microorganisms are primarily mediated by genes acquired from exogenous DNA. The dynamics of the horizontal transfer is performed by mobile genetic elements which carry resistance genes. The wide distribution of these structures, such as the SXT element originally isolated from V. cholerae, has contributed to the spread of specific clonal complexes in certain geographical areas. This pioneering study in Brazil researched the presence of SXT elements in the group of bacterial species in environmental gamma-proteobacteria species, determined their structural and functional characteristics, including genes for resistance to antibiotics and the antibiotic susceptibility among bacterial isolates that harbor them. The result was the classification of 43 SXT elements found in Brazil, by comparison with those found in the literature. Among the SXT elements found, four are sheltered by Morganella morganii, unprecedented in the literature. Knowledge of bacterial evolution is an important to establish effective strategies to control and treat infections without increasing the selective pressure on microorganisms, as well as a precise instrument and very important tool to support epidemiological studies.


Assuntos
DNA Bacteriano , Meio Ambiente , Gammaproteobacteria , Genoma Bacteriano , Resistência Microbiana a Medicamentos/genética , Transferência Genética Horizontal/genética , Adaptação Biológica , Componentes Genômicos , Biologia Molecular , Saúde Pública
4.
Braz. j. microbiol ; 42(1): 41-45, Jan.-Mar. 2011. ilus
Artigo em Inglês | LILACS | ID: lil-571372

RESUMO

The succession and growth strategy of a spring microbial community under earthquake action were investigated. The majority of pre-earthquake isolates belonged to the Gammaproteobacteria, including two numerically dominant Stenotrophomonas sp. RB25 and Acinetobacter sp. RB11 (r-strategists). The predominant post-earthquake isolates were Alphaproteobacteria, with Rhizobium sp. RA42 (K-strategists) being dominant among these organisms.


Assuntos
Crescimento Bacteriano , Biota , Terremotos , Microbiologia Ambiental , Infecções por Bactérias Gram-Negativas , Gammaproteobacteria/isolamento & purificação , Rhizobium/isolamento & purificação , Stenotrophomonas/isolamento & purificação , Métodos , Estratégias de Saúde , Métodos
5.
Braz. j. med. biol. res ; 35(6): 645-650, June 2002. ilus
Artigo em Inglês | LILACS | ID: lil-309520

RESUMO

The availability of the genome sequence of the bacterial plant pathogen Xylella fastidiosa, the causal agent of citrus variegated chlorosis, is accelerating important investigations concerning its pathogenicity. Plant vessel occlusion is critical for symptom development. The objective of the present study was to search for information that would help to explain the adhesion of X. fastidiosa cells to the xylem. Scanning electron microscopy revealed that adhesion may occur without the fastidium gum, an exopolysaccharide produced by X. fastidiosa, and X-ray microanalysis demonstrated the presence of elemental sulfur both in cells grown in vitro and in cells found inside plant vessels, indicating that the sulfur signal is generated by the pathogen surface. Calcium and magnesium peaks were detected in association with sulfur in occluded vessels. We propose an explanation for the adhesion and aggregation process. Thiol groups, maintained by the enzyme peptide methionine sulfoxide reductase, could be active on the surface of the bacteria and appear to promote cell-cell aggregation by forming disulfide bonds with thiol groups on the surface of adjacent cells. The enzyme methionine sulfoxide reductase has been shown to be an auxiliary component in the adhesiveness of some human pathogens. The negative charge conferred by the ionized thiol group could of itself constitute a mechanism of adhesion by allowing the formation of divalent cation bridges between the negatively charged bacteria and predominantly negatively charged xylem walls


Assuntos
Cálcio , Citrus , Gammaproteobacteria , Doenças das Plantas , Compostos de Sulfidrila , Cálcio , Adesão Celular , Agregação Celular , Citrus , Microanálise por Sonda Eletrônica , Gammaproteobacteria , Genoma Bacteriano , Magnésio , Oxirredutases , Compostos de Sulfidrila , Enxofre
6.
Rev. argent. microbiol ; 33(3): 141-148, jul.-sept. 2001.
Artigo em Espanhol | LILACS | ID: lil-332488

RESUMO

During screening for oil-degrading bacteria in sediments of BahÝa Blanca estuary, a bacterial strain was isolated which uses a limited number of organic compounds, especially lineal hydrocarbons. The goals of this study were to characterize the strain and to evaluate its activity on crude oil. Based on phenotypic characteristics and the analysis of 16S rDNA sequences, it was determined that the strain is strongly related to Alcanivorax borkumensis. The strain was cultured, under quasicontinuous conditions, with crude oil as sole source of carbon and energy. After 30 days of incubation, n-alkane decrease reached 86. The isoalkanes pristane and phitane were degraded more slowly, but a decrease of about 63 was obtained. The strain studied would be useful for the bioremediation of the local coasts, so that this study will be continued in order to obtain its successful application in the environment.


Assuntos
Biodegradação Ambiental , Hidrocarbonetos , Gammaproteobacteria/isolamento & purificação , Microbiologia da Água , Argentina , Cloreto de Sódio/análise , Gammaproteobacteria/classificação , Gammaproteobacteria/metabolismo , Gammaproteobacteria/ultraestrutura , Poluição Química da Água
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...