Papers by José Daniel Vieira
Enciclopédia Biosfera
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Phytopathology®, 2015
The fungus Rhizoctonia solani anastomosis group (AG)-1 IA emerged in the early 1990s as an import... more The fungus Rhizoctonia solani anastomosis group (AG)-1 IA emerged in the early 1990s as an important pathogen causing foliar blight and collar rot on pastures of the genus Urochloa (signalgrass) in South America. We tested the hypothesis that this pathogen emerged following a host shift or jump as a result of geographical overlapping of host species. The genetic structure of host and regional populations of R. solani AG-1 IA infecting signalgrass, rice, and soybean in Colombia and Brazil was analyzed using nine microsatellite loci in 350 isolates to measure population differentiation and infer the pathogen reproductive system. Phylogeographical analyses based on the microsatellite loci and on three DNA sequence loci were used to infer historical migration patterns and test hypotheses about the origin of the current pathogen populations. Cross pathogenicity assays were conducted to measure the degree of host specialization in populations sampled from different hosts. The combined ana...
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Brazilian Journal of Microbiology
Helicobacter pylori is the etiological agent of chronic gastritis, peptic ulcer, and gastric canc... more Helicobacter pylori is the etiological agent of chronic gastritis, peptic ulcer, and gastric cancer. The duodenal ulcer-promoting gene dupA, which is located in the plasticity region of the H. pylori genome, is homologous to the virB gene which encodes a type IV secretion protein in Agrobacterium tumefaciens. Studies have shown associations between H. pylori dupA-positive strains and gastroduodenal diseases. However, whether dupA acts as a risk factor or protective factor in these diseases remains unclear. Therefore, in this study, we aimed to verify the presence of the dupA gene in infectious H. pylori strains in the Brazilian mid-west and to investigate its association with the clinical outcomes of patients with dyspepsia. Additionally, the phylogenetic origin of the strains was determined. Gastric biopsies from 117 patients with dyspepsia were analyzed using histological and molecular techniques. The hpx gene (16S rRNA) was used to screen for H. pylori infection, and positive samples were then subjected to dupA gene detection and sequencing. The estimated prevalence of H. pylori infection was 64.1%, with the dupA gene being detected in a high proportion of infectious strains (70.7%). Furthermore, a risk analysis revealed that for women, a dupA-positive H. pylori infection increased the chance of developing gastritis by twofold. The partial dupA sequences from isolated infectious strains in this work are similar to those of strains isolated in westerns countries. This study provides useful insights for understanding the role of the H. pylori dupA gene in disease development.
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Research, Society and Development
The Meia Ponte River – Goiás/Brazil, is responsible for benefiting about 2 million people in Goiá... more The Meia Ponte River – Goiás/Brazil, is responsible for benefiting about 2 million people in Goiás State. However, the increase in pollution with the disposal of sewage, chemicals and drug remains have contributed to the increase in bacterial resistance and the exchange of resistance genes. The objective of this study was to isolate, identify and analyze the resistance profile of gram-positive bacteria present in raw water and sediment of the Meia Ponte River – Goiás. The samples were collected from four sampling points and two collections were carried out, one in the dry season and the other in the rainy season. The isolated bacteria were identificated, then the antibiogram was performed. A total of 75 strains were isolated, 72.0% (54/75) of Streptococcus spp., 12.0% (9/75) of Staphylococcus spp., 9.3% (7/75) of Bacillus spp. and 6.7% (5/75) of Enterococcus spp. Furthermore, 52.0% (39/75) of the isolated strains were from raw water and 48.0% (36/75) were isolated from the sediment....
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Enciclopédia Biosfera
E cada vez mais presente pesquisas com microrganismos endofiticos produtores dediferentes metabol... more E cada vez mais presente pesquisas com microrganismos endofiticos produtores dediferentes metabolitos, tais como as enzimas hidroliticas, que apresentam grandeaplicabilidade nos processos industriais, devido a sua ampla variedade de estruturae de aplicacoes, alta especificidade e estabilidade, baixo impacto ao meio ambiente,possibilidade de producao em grande escala em curto periodo de tempo e combaixo custo. O presente estudo teve como objetivo isolar bacterias endofiticas deTridax procumbens (L.) e avaliar a producao de enzimas hidroliticas produzidas poressas bacterias. Um total de oito bacterias endofiticas, de diferentes partes da plantaforam selecionadas e analisadas quanto a sua capacidade de sintese das enzimasamilase, β-glucosidase, celulase, endoglucanase, esterase, exoglucanase, lipase,pectinase, protease e xilanase, usando meios de cultura solidos especificos paraproducao de cada enzima. Das oito bacterias isoladas, todas apresentaram atividadepectinolitica e proteolitica, 87,5% atividade β-glucosidase e celulolitica (cana-de- acucar), 75% atividade endoglucanase e exoglucanase, 62,5% atividade xilanase, 50% atividade amilolitica, 37,5% atividade celulolitica (bambu) e esterasica, nenhuma apresentou atividade lipasica. Em conclusao, os isolados exibem potencial como produtores de enzimas hidroliticas de interesse industrial.
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Revista de Biología Tropical
Phyllomedusa azurea is a frog species well distributed geographically in South America, including... more Phyllomedusa azurea is a frog species well distributed geographically in South America, including Brazilian biomes as Pantanal and Cerrado. Compared with other anurans from the Phyllomedusinae family, there are few reports on the bioactive potential of skin-derived molecules from this species. In this perspective, the aim of the present study was to evaluate the in vitro antibacterial activity of skin secretion of P. azurea by detection of Minimum Inhibitory Concentration (MIC) of the growth of bacterial indicator strains and to determine if occurs a changing in the bacterial cell envelope permeability. The MIC determination was carried out by the microdilution plate method. The absorbance was measured and analyzed statistically using the t-test to compare two groups (0.05 % of significance). The impact of the crude extract on cell envelope permeability of Staphylococcus aureus ATCC 25923 was conducted by the crystal violet assay, and the absorbance was measured spectrophotometry fo...
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Enciclopédia Biosfera, Dec 5, 2017
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International Journal of Microbiology Research
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Environmental Geochemistry and Health
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Anais da Academia Brasileira de Ciências
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Anais da Academia Brasileira de Ciencias
In the present work, different Brazilian biomes aiming to identify and select cyclodextrin glycos... more In the present work, different Brazilian biomes aiming to identify and select cyclodextrin glycosyltransferase-producer bacteria are explored. This enzyme is responsible for converting starch to cyclodextrin, which are interesting molecules to carry other substances of economic interest applied by textile, pharmaceutical, food, and other industries. Based on the enzymatic index, 12 bacteria were selected and evaluated, considering their capacity to produce the enzyme in culture media containing different starch sources. It was observed that the highest yields were presented by the bacteria when grown in cornstarch. These bacteria were also characterized by sequencing of the 16S rRNA region and were classified as Bacillus, Paenibacillus, Gracilibacillus and Solibacillus.
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Agrarian Academy
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Enciclopédia Biosfera, 2016
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Pesquisa Agropecuária Tropical, 2016
Microorganisms play a vital role in maintaining soil fertility and plant health. They can act as ... more Microorganisms play a vital role in maintaining soil fertility and plant health. They can act as biofertilizers and increase the resistance to biotic and abiotic stress. This study aimed at isolating and characterizing plant growth-promoting bacteria associated with sugarcane, as well as assessing their ability to promote plant growth. Endophytic bacteria from leaf, stem, root and rhizosphere were isolated from the RB 867515 commercial sugarcane variety and screened for indole acetic acid (IAA) production, ability to solubilize phosphate, fix nitrogen and produce hydrogen cyanide (HCN), ammonia and the enzymes pectinase, cellulase and chitinase. A total of 136 bacteria were isolated, with 83 of them presenting some plant growth mechanism: 47 % phosphate solubilizers, 26 % nitrogen fixers and 57 % producing IAA, 0.7 % HCN and chitinase, 45 % ammonia, 30 % cellulose and 8 % pectinase. The seven best isolates were tested for their ability to promote plant growth in maize. The isolates ...
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Enciclopédia Biosfera, 2016
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Enciclopédia Biosfera, 2016
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Revista do Instituto de Medicina Tropical de São Paulo, 2015
The evaluation of workers as potential reservoirs and disseminators of pathogenic bacteria has be... more The evaluation of workers as potential reservoirs and disseminators of pathogenic bacteria has been described as a strategy for the prevention and control of healthcare-associated infections (HAIs). The aim of this study was to evaluate the presence of Enterobacteriaceae in the oral cavity of workers at an oncology hospital in the Midwest region of Brazil, as well as to characterize the phenotypic profile of the isolates. Saliva samples of 294 workers from the hospital’s healthcare and support teams were collected. Microbiological procedures were performed according to standard techniques. Among the participants, 55 (18.7%) were colonized by Enterobacteriaceae in the oral cavity. A total of 64 bacteria were isolated, including potentially pathogenic species. The most prevalent species was Enterobacter gergoviae (17.2%). The highest rates of resistance were observed for β-lactams, and 48.4% of the isolates were considered multiresistant. Regarding the enterobacteria isolated, the pro...
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Algal Research, 2015
ABSTRACT Due to the currently abundant supply of marine microalgae, which can be found in seawate... more ABSTRACT Due to the currently abundant supply of marine microalgae, which can be found in seawater, as well as microalgae's ability to uptake different chemicals, it appears as a promising raw material with potential for many commercial uses. Despite having a high amount of metal in their biomass, the lipids within marine microalgae can be converted into biodiesel. Analyses of 26 chemical elements (Al, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Sn, Sr, Ti, Tl, V, and Zn) were performed by ICP-OES with the goal of quantifying the inorganic content of marine microalgae's biomass. Regardless of the cultivation media used, microalgae presented differences in their chemical element profile. Strains showed a 12.9% to 36.3% mass of analyzed elements per dry biomass, which represent a relatively high percentage for a feedstock used in biofuels. Among the 36 assayed microalgae, Biddulphia sp., Planktolyngbya limnetica, Amphora sp. (1), Navicula sp. (3) and Synechococcus sp. are most indicated for this purpose as they contain a lower concentration of chemical elements when compared to other samples. However, their profile warns that water quality control is needed for toxic metals such as Ba, Cd, and Pb.
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Revista da Sociedade Brasileira de Medicina Tropical, 2011
INTRODUÇÃO: O aumento da prevalência de isolados de enterococos em hospitais, particularmente Ent... more INTRODUÇÃO: O aumento da prevalência de isolados de enterococos em hospitais, particularmente Enterococcus resistente à vancomicina (VRE), é importante por causa da limitada terapia antimicrobiana efetiva para o tratamento de infecções enterocócicas. MÉTODOS: O presente trabalho apresentou uma investigação retrospectiva de dados de suscetibilidade in vitro quantitativa para uma variedade de antimicrobianos frente aos isolados de Enterococcus spp. e avaliação da associação de resistência entre os agentes antimicrobianos apontados como escolha para o tratamento de infecções causadas por VRE, através do cálculo do risco relativo. RESULTADOS: Dos 156 isolados de enterococos, 40 (25,6%) foram resistentes a três ou mais antimicrobianos, incluindo 7,7% (n = 12/156) resistentes à vancomicina. A associação de resistência elevada foi mais pronunciada entre os isolados de VREs com antimicrobianos alternativos e primários para o tratamento de infecções causadas por estes patógenos, incluindo am...
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Revista de Patologia Tropical, 2009
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Papers by José Daniel Vieira