Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
Mais filtros










Filtros aplicados
Intervalo de ano de publicação
1.
Biol. Res ; 53: 29, 2020. graf
Artigo em Inglês | LILACS | ID: biblio-1124216

RESUMO

Abstract Arid environments are defined by the lack of water availability, which is directly related to the mean annual precipitation (MAP), and high values of solar irradiation, which impacts the community composition of animals, plants, and the microbial structure of the soil. Recent advances in NGS technologies have expanded our ability to characterize micro- biomes, allowing environmental microbiologists to explore the complete microbial structure. Intending to identify and describe the state-of-the-art of bacterial communities in arid soils at a global scale, and to address the effect that some environmental features may have on them, we performed a systematic review based on the PRISMA guideline. Using a combination of keywords, we identified a collection of 66 studies, including 327 sampled sites, reporting the arid soil bacterial community composition by 16S rDNA gene high-throughput sequencing. To identify factors that can modulate bacterial communities, we extracted the geographical, environmental, and physicochemical data. The results indicate that even though each sampled site was catalogued as arid, they show wide variability in altitude, mean annual temperature (MAT), soil pH and electric conductivity, within and between arid environments. We show that arid soils display a higher abundance of Actinobacteria and lower abundance of Proteobacteria, Cyanobacteria, and Planctomycetes, compared with non-arid soil microbiomes, revealing that microbial structure seems to be strongly modulated by MAP and MAT and not by pH in arid soils. We observed that environmental and physicochemical features were scarcely described among studies, hence, we propose a reporting guideline for further analysis, which will allow deepening the knowledge of the relationship between the microbiome and abiotic factors in arid soil. Finally, to understand the academic collaborations landscape, we developed an analysis of the author's network, corroborating a low degree of connectivity and collaborations in this research topic. Considering that it is crucial to understand how microbial processes develop and change in arid soils, our analysis emphasizes the need to increase collaborations between research groups worldwide.


Assuntos
Animais , Microbiologia do Solo , Microbiota/genética , Plantas , Solo , Proteobactérias
2.
Electron. j. biotechnol ; 41: 72-80, sept. 2019. ilus, tab, graf
Artigo em Inglês | LILACS | ID: biblio-1087172

RESUMO

Background: Microbial community analysis of electronic waste (e-waste)-polluted environments is of interest to understand the effect of toxic e-waste pollutants on the soil microbial community and to evaluate novel microorganisms resisting the toxic environment. The present study aims to investigate the bacterial community structure in soils contaminated with e-waste from various sites of Loni and Mandoli (National Capital Region (NCR), India) where e-waste dumping and recycling activities are being carried out for many years. Results: Interferences to soil metagenomic DNA extraction and PCR amplification were observed because of the presence of inhibiting components derived from circuit boards. Whole-metagenome sequencing on the Illumina MiSeq platform showed that the most abundant phyla were Proteobacteria and Firmicutes. Deltaproteobacteria and Betaproteobacteria were the most common classes under Proteobacteria. Denaturing gradient gel electrophoresis (DGGE) analysis of the bacterial 16S rRNA gene showed that e-waste contamination altered the soil bacterial composition and diversity. There was a decrease in the number of predominant bacterial groups like Proteobacteria and Firmicutes but emergence of Actinobacteria in the contaminated soil samples. Conclusions: This is the first report describing the bacterial community structure of composite soil samples of ewaste-contaminated sites of Loni and Mandoli, Delhi NCR, India. The findings indicate that novel bacteria with potential bioremediating properties may be present in the e-waste-contaminated sites and hence need to be evaluated further.


Assuntos
Microbiologia do Solo , Bactérias/isolamento & purificação , Bactérias/genética , Resíduo Eletrônico/análise , Poluentes do Solo , Reação em Cadeia da Polimerase , Metais Pesados , Proteobactérias/isolamento & purificação , Metagenômica , Eletroforese em Gel de Gradiente Desnaturante , Microbiota , Firmicutes/isolamento & purificação , Índia
3.
Braz. j. biol ; 78(1): 108-116, Feb. 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-888831

RESUMO

Abstract Although Planktothrix agardhii often produces toxic blooms in eutrophic water bodies around the world, little is known about the fate of the organic matter released by these abundant Cyanobacteria. Thus, this study focused in estimating the bacterial consumption of the DOC and DON (dissolved organic carbon and dissolved organic nitrogen, respectively) produced by axenic P. agardhii cultures and identifying some of the bacterial OTUs (operational taxonomic units) involved in the process. Both P. agardhii and bacterial inocula were sampled from the eutrophic Barra Bonita Reservoir (SP, Brazil). Two distinct carbon degradation phases were observed: during the first three days, higher degradation coefficients were calculated, which were followed by a slower degradation phase. The maximum value observed for particulate bacterial carbon (POC) was 11.9 mg L-1, which consisted of 62.5% of the total available DOC, and its mineralization coefficient was 0.477 day-1 (t½ = 1.45 days). A similar pattern of degradation was observed for DON, although the coefficients were slightly different. Changes in the OTUs patterns were observed during the different steps of the degradation. The main OTUs were related to the classes Alphaproteobacteria (8 OTUs), Betaproteobacteria (2 OTUs) and Gammaproteobacteria (3 OTUs). The genus Acinetobacter was the only identified organism that occurred during the whole process. Bacterial richness was higher at the slower degradation phase, which could be related to the small amounts of DOM (dissolved organic matter) available, particularly carbon. The kinetics of the bacterial degradation of P. agardhii-originated DOM suggests minimal loss of DOM from the Barra Bonita reservoir.


Resumo Embora Planktothrix agardhii frequentemente forme florações tóxicas em corpos d'água pelo mundo, pouco ainda se sabe sobre o destino da matéria orgânica liberada por essa abundante Cyanobacteria. Assim, este estudo foi focado na estimativa do consumo bacteriano do carbono orgânico dissolvido (DOC) e nitrogênio orgânico dissolvido (DON) produzido por culturas axênicas de P. agardhii e identificação de algumas das unidades taxonômicas operacionais (OTUs) bacterianas envolvidas no processo. Ambos a linhagem de P. agardhii e o inóculo bacteriano foram amostrados do reservatório eutrófico de Barra Bonita (SP, Brasil). Foram observadas duas fases distintas da degradação do DOC: durante os três primeiros dias, coeficientes mais altos de degradação foram calculados, que foram então seguidos por uma fase mais lenta da degradação do carbono. O valor máximo calculado para o carbono bacteriano particulado (POC) foi de 11,9 mgL-1, o que equivale a aproximadamente 62,5% do DOC disponível para consumo, e o seu coeficiente de mineralização foi de 0,477 dia-1 (t1/2 = 1,45 dias). Um padrão similar de degradação foi observado para DON, embora os coeficientes sejam ligeiramente diferentes. Foram observadas mudanças nos padrões de OTUs durante os diferentes passos da degradação. As principais OTUs foram relacionadas às classes Alphaproteobacteria (8 OTUs), Betaproteobacteria (2 OTUs) e Gammaproteobacteria (3 OTUs). O gênero Acinetobacter foi o único organismo identificado que ocorreu durante todo o processo. A maior riqueza bacteriana foi observada durante a fase lenta de degradação, o que pode estar relacionado às pequenas quantidades de matéria orgânica dissovida (DOM) disponíveis, particularmente o carbono. A cinética da degradação bacteriana da MOD de P. agardhii, quando comparada ao tempo de retenção do reservatório, sugere que existe uma perda mínima após sua liberação em Barra Bonita.


Assuntos
Carbono/metabolismo , Cianobactérias/metabolismo , Cianobactérias/química , Proteobactérias/metabolismo , Substâncias Húmicas/análise , Nitrogênio/metabolismo , Biodegradação Ambiental , Carbono/análise , Eutrofização , Nitrogênio/análise
4.
J. venom. anim. toxins incl. trop. dis ; 24: 41, 2018. tab, graf, ilus
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-984693

RESUMO

The oral cavities of snakes are replete with various types of bacterial flora. Culture-dependent studies suggest that some of the bacterial species are responsible for secondary bacterial infection associated with snakebite. A complete profile of the ophidian oral bacterial community has been unreported until now. Therefore, in the present study, we determined the complete bacterial compositions in the oral cavity of some snakes from India. Methods: Total DNA was isolated from oral swabs collected from three wild snake species (Indian Cobra, King Cobra and Indian Python). Next, the DNA was subjected to PCR amplification of microbial 16S rRNA gene using V3-region-specific primers. The amplicons were used for preparation of DNA libraries that were sequenced on an Illumina MiSeq platform. Results: The cluster-based taxonomy analysis revealed that Proteobacteria and Actinobacteria were the most predominant phyla present in the oral cavities of snakes. This result indicates that snakes show more similarities to birds than mammals as to their oral bacterial communities. Furthermore, our study reports all the unique and common bacterial species (total: 147) found among the oral microbes of snakes studied, while the majority of commonly abundant species were pathogens or opportunistic pathogens to humans. A wide difference in ophidian oral bacterial flora suggests variation by individual, species and geographical region. Conclusion: The present study would provide a foundation for further research on snakes to recognize the potential drugs/antibiotics for the different infectious diseases.(AU)


Assuntos
Serpentes , Infecções Bacterianas , Actinobacteria , Proteobactérias , Sequenciamento de Nucleotídeos em Larga Escala , Antibacterianos , Reação em Cadeia da Polimerase
5.
Infectio ; 21(2): 129-131, abr.-jun. 2017. graf
Artigo em Espanhol | LILACS, COLNAL | ID: biblio-892716

RESUMO

Chromobacterium violaceum es una bacteria gramnegativa anaeróbica facultativa, que habita en el suelo y el agua de las áreas tropicales y subtropicales. La infección en seres humanos es rara. A continuación se presentan dos casos; una lactante mayor, indígena, quien posterior a baño de inmersión en aguas estancadas comienza a presentar fiebre con aumento de volumen y limitación funcional y gonalgia izquierda, se realiza lavado articular, se toma muestra para cultivo con crecimiento para Chromobacterium violaceum. Un escolar masculino de 7 años de edad con antecedente de Leucemia Linfoblastica Aguda con recaída en sistema nervioso central, cumpliendo esquema de altas dosis de metotrexate; quien comienza a presentar fiebre y signos de flogosis en sitio de colocación de cáteter de vía central, el cual es retirado y cultivado con crecimiento para Chromobacterium violaceum. Esta infección en humanos es una enfermedad grave y sistémica con una alta tasa de mortalidad.


Chromobacterium violaceum is a Gram-negative facultative anaerobic bacterium, which lives in the soil and water of subtropical and tropical areas. Infection in humans is rare. Here we present two cases. One was in one indigenous newborn, who after one immersion in stagnant waters presented fever and increase in the volume of testicle and limitation in movility of the left limb. After arthrocentesis of left knee and culture of the sinovial liquid, growth of Cromabacterium violaceum was reported. Another case was a male school of 7 years old with a history of acute lymphoblastic leukemia relapse in the central nervous system, that completed his high dose methotexate scheme. Some days after he presented fever and edema at the site of central venous catheterization. The catheter was retired and it was obtained growth of Chromobacterium violaceum. Human infection with Chromobacterium violaceum is a severe and systemic disease with a high mortality rate.


Assuntos
Humanos , Masculino , Feminino , Pré-Escolar , Criança , Pele , Chromobacterium , Infecções , Clima Tropical , Proteobactérias , Febre , Povos Indígenas
6.
Braz. j. microbiol ; 47(2): 345-351, Apr.-June 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-780844

RESUMO

Abstract The development of showerhead biofilms exposes the user to repeated contact with potentially pathogenic microbes, yet we know relatively little about the content of these aggregates. The aim of the present study was to examine the microbial content of tape-like films found protruding from a domestic showerhead. Culturing showed that the films were dominated by aerobic α- and β-proteobacteria. Three isolates made up almost the entire plate count. These were a Brevundimonas species, a metalophilic Cupriavidus species and a thermophile, Geobacillus species. Furthermore, it was shown that the Cupriavidus isolate alone had a high capacity for biofilm formation and thus might be the initiator of biofilm production. A clone library revealed the same general composition. However, half of the 70 clones analyzed could not be assigned to a particular bacterial phylum and of these 29 differed from one another by only 1–2 base pairs, indicating a single species. Thus both the culture dependent and culture independent characterizations suggest a simple yet novel composition. The work is important as the biofilm is fundamentally different in form (tape-like) and content from that of all previously reported ones, where variously Mycobacterium, Methylobacterium and Xanthomonas species have dominated, and extremophiles were not reported.


Assuntos
Biofilmes , Proteobactérias/isolamento & purificação , Proteobactérias/fisiologia , Coloração e Rotulagem , DNA Bacteriano/genética , RNA Ribossômico 16S/genética , Proteobactérias/genética , Proteobactérias/química
7.
Braz. j. microbiol ; 45(4): 1161-1171, Oct.-Dec. 2014. graf, tab
Artigo em Inglês | LILACS | ID: lil-741265

RESUMO

To appreciate differences in benthic bacterial community composition at the relatively pristine Tuvem and the anthropogenically-influenced Divar mangrove ecosystems in Goa, India, parallel tag sequencing of the V6 region of 16S rDNA was carried out. We hypothesize that availability of extraneously-derived anthropogenic substrates could act as a stimulatant but not a deterrent to promote higher bacterial diversity at Divar. Our observations revealed that the phylum Proteobacteria was dominant at both locations comprising 43-46% of total tags. The Tuvem ecosystem was characterized by an abundance of members belonging to the class Deltaproteobacteria (21%), ~ 2100 phylotypes and 1561 operational taxonomic units (OTUs) sharing > 97% similarity. At Divar, the Gammaproteobacteria were ~ 2x higher (17%) than at Tuvem. A more diverse bacterial community with > 3300 phylotypes and > 2000 OTUs mostly belonging to Gammaproteobacteria and a significantly higher DNT (n = 9, p < 0.001, df = 1) were recorded at Divar. These findings suggest that the quantity and quality of pollutants at Divar are perhaps still at a level to maintain high diversity. Using this technique we could show higher diversity at Divar with the possibility of Gammaproteobacteria contributing to modulating excess nitrate.


Assuntos
Ecossistema , Microbiologia Ambiental , Variação Genética , Proteobactérias/classificação , Proteobactérias/genética , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Índia , /genética , Análise de Sequência de DNA , Áreas Alagadas
8.
Biol. Res ; 47: 1-6, 2014. graf, tab
Artigo em Inglês | LILACS | ID: biblio-950763

RESUMO

BACKGROUND: Marine invertebrate-associated microbial communities are interesting examples of complex symbiotic systems and are a potential source of biotechnological products. RESULTS: In this work, pyrosequencing-based assessment from bacterial community structures of sediments, two sponges, and one zoanthid collected in the Mexican Caribbean was performed. The results suggest that the bacterial diversity at the species level is higher in the sediments than in the animal samples. Analysis of bacterial communities' structure showed that about two thirds of the bacterial diversity in all the samples belongs to the phyla Acidobacteria and Proteobacteria. The genus Acidobacteriumappears to dominate the bacterial community in all the samples, reaching almost 80% in the sponge Hyrtios. CONCLUSIONS: Our evidence suggests that the sympatric location of these benthonic species may lead to common bacterial structure features among their bacterial communities. The results may serve as a first insight to formulate hypotheses that lead to more extensive studies of sessile marine organisms' microbiomes from the Mexican Caribbean.


Assuntos
Animais , Poríferos/microbiologia , Antozoários/microbiologia , Acidobacteria/fisiologia , Simpatria , Microbiota/fisiologia , Filogenia , Poríferos/classificação , Simbiose/fisiologia , RNA Ribossômico 16S/análise , Região do Caribe , Sedimentos Geológicos/microbiologia , Proteobactérias/classificação , Proteobactérias/fisiologia , Antozoários/classificação , Biodiversidade , México
9.
São Paulo; s.n; s.n; 2014. 82 p. tab, graf, ilus.
Tese em Português | LILACS | ID: biblio-847153

RESUMO

Pseudomonas aeruginosa é uma gamaproteobactéria com capacidade de colonizar diversos tipos de ambiente e infectar hospedeiros filogeneticamente distintos. Em humanos, comporta-se como um patógeno oportunista,estando frequentemente relacionada à infecções em indivíduos imunocomprometidos e indivíduos portadores de fibrose cística. Um mecanismo importante para a versatilidade de P. aeruginosa é o sistema de percepção de quórum (QS), onde a bactéria pode vincular expressão gênica à densidade populacional e às características do ambiente. Atualmente, sabe-se que muitos outros reguladores estão interligados com QS, entre eles, a proteína reguladora RsmA e os pequenos RNAs RsmZ e RsmY. Além disso, diversos fatores importantes para a patogenicidade da bactéria são reguladas por QS. Em P. aeruginosa PA14, um fator importante para a patogenicidade em diversos hospedeiros é a proteína KerV, cujo envolvimento com QS foi descrito pela primeira vez neste trabalho. A linhagem D12, que possui uma deleção no gene kerV, mostrou alterações em fenótipos regulados por QS, como a maior produção de piocianina, composto que contribui para virulência e persistência das infecções causada por P. aeruginosa. Por ser facilmente detectável e pela regulação de sua síntese não ter sido completamente explorada em PA14, a expressão dos genes responsáveis pela produção de piocianina é um interessante repórter na investigação do possível envolvimento de KerV com QS. Além de piocianina, D12 apresenta níveis reduzidos de ramnolipídeos. Esses fenótipos somados se assemelham aos fenótipos da mutação de rsmA, sugerindo o envolvimento de KerV com os sistemas QS e Gac-Rsm direta ou indiretamente. Neste trabalho, mostramos que KerV exerce um efeito negativo na regulação dos operons phz1 e phz2, responsáveis pela síntese de piocianina, alterando a expressão desses genes. KerV exerce também um efeito positivo na expressão da proteína RsmA, responsável pela repressão de diversos genes alvos, onde RsmA se liga ao sítio de ligação ao ribossomo no mRNA, impedindo a tradução. Ensaios de gel shift mostraram que a ligação direta de RsmA na sequência líder de phzA1 e phzA2 ocorre, elucidando a maneira pela qual KerV está envolvido na regulação da expressão dos operons phz em P. aeruginosa PA14. Mostramos também que phz2 é ativo e contribui para a síntese de piocianina, pois na ausência de phz1, os níveis do pigmento são maiores do que aqueles detectados em PA14. Isso sugere uma maior expressão de phz2 e uma regulação diferencial dos operons de acordo com as condições ambientais como possível estratégia para manter os níveis desse composto. Uma evidência dessa regulação diferencial é vista no mutante lasR. Na fase inicial de crescimento, esse mutante não produz piocianina, porém quando exposto a tempos mais longos de cultivo, a produção de piocianina é maior quando comparada a PA14. Isso é reflexo da ativação da expressão de phz1 no mutante lasR em fase estacionária tardia, enquanto phz2 permanece não expresso. Isso indica que phz2 é dependente de LasR, ainda que indiretamente. Já phz1, embora tenha sua expressão influenciada por LasR no estágio inicial de crescimento, na fase estacionária é regulado por outros fatores independentes de las


Pseudomonas aeruginosa is a gammaproteobacterium that colonizes several environments and infects phylogenetically distinct hosts. It behaves as an opportunistic pathogen in humans, often related to infection in immunocompromised individuals and cystic fibrosis patients. An important mechanism for P. aeruginosa versatility is the quorum sensing (QS) network, that allows bacteria to link gene expression to population density and environmental traits. Several additional regulators are interconnected with QS, as the regulatory mRNA binding protein RsmA and the non-coding small RNAs RsmZ and RsmY. Futhermore, key factors for pathogenicity are QS-regulated. In P. aeruginosa PA14, an important pathogenicity-related factor is the KerV protein, described for the first time here as involved in QS. D12 strain, that harbor a deletion in the kerV gene, shows alterations in QS-regulated phenotypes, such as high production of pyocyanin, a compound that contributes to virulence and persistence of P. aeruginosa infections. As the production of pyocyanin is easily detected and all mechanisms involved in its synthesis regulation are not fully described, the expression of genes responsible for production of this pigment is a good reporter to investigate KerV involvement in the QS network. Additionally, D12 also shows lower levels of rhamnolipids, another QS-regulated trait. Taken together, these phenotypes resemble the effects of a rsmA mutation, suggesting KerV involvement with QS and Gac-Rsm systems. In this work, we propose that KerV exerts a negative effect in the regulation of phz1 and phz2 operons, responsible for pyocyanin synthesis, by alterating the expression of these genes. KerV also has a positive effect on rsmA expression, responsible for the repression of several genes by blocking the ribosome binding site preventing the translation. Gel shift assays showed that RsmA binds directly in the leader sequence of phzA1 and phzA2, elucidating the manner in which KerV is involved in the regulation of phz operons expression in P. aeruginosa PA14. We also demonstrate that phz2 is actively expressed and contributes to pyocyanin production in PA14, since in the phz1 mutant the levels of pyocyanin are even higher than in the wild type strain. This suggests a phz2 higher expression and a differential regulation of phz operons according to environmental changes as a mechanism to maintain the levels of pyocyanin synthesis. An evidence for this regulation is the synthesis of pyocyanin by the lasR mutant, which does not make pyocyanin at early growth stages. However, at late stationary phase, pyocyanin production is even higher than in the wild-type strain, reflecting the LasR-independent regulation of phz1 expression, while phz2 operon remains silent


Assuntos
Pseudomonas aeruginosa/crescimento & desenvolvimento , Percepção de Quorum , Infecções Bacterianas , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica/genética , Biologia Molecular/instrumentação , Reação em Cadeia da Polimerase/métodos , Proteobactérias , Pseudomonas/citologia , Piocianina/farmacologia
10.
Electron. j. biotechnol ; 12(2): 5-6, Apr. 2009. ilus, tab
Artigo em Inglês | LILACS | ID: lil-551366

RESUMO

This study was undertaken to characterize the alpha subgroup of the proteobacteria causing the huanglongbing (HLB) disease of citrus from three different ecological zones of Kenya namely the Lower highlands (LH2, LH3, 1800-1900 m above sea level); Upper midlands (UM3, UM4, 1390-1475m), Lower midlands (LM5, LM4, LM3 of 1290-1340-1390m), by isolation and sequencing DNA encoding the L10 and L12 ribosomal proteins and the intergenic region. A 7I6-basepair DNA fragment was amplified and sequenced and consisted of 536 basepairs of DNA encoding the L10 protein, 44 basepairs of DNA intergenic region and 136 basepairs of DNA that partially encodes the L12 protein. Sequences of rpL10/L12 protein genes from Kenyan strains were 98 percent and 81 percent similar to the South African 'Candidatus Liberibacter africanus strain Nelspruit' and the Asian 'Candidatus Liberibacter asiaticus' strains, respectively. The intergenic rDNA sequence of Kenyan strain from UM and LM showed 84 percent similarity with 'Candidatus L. africanus strain Nelspruit' and 50 percent similarity with 'Candidatus L. asiaticus' strain. However, the LH strain had an 11- basepairs deletion, while the LM4 had a 5-basepair deletion in the intergenic region compared to 'Candidatus L. africanus strain Nelspruit'. The L10 amino acid sequence was 100 percent homologous among HLB bacteria obtained from the agro-ecological zones in Kenya and the L10 protein sequence was also homologus to 'Candidatus L. africanus strain Nelspruit'. Nevertheless, the L10 amino acid sequence of 'Candidatus L. asiaticus' and the 'Candidatus L. africanus subsp. capensis' differed from the Kenyan strains by 18.36 percent and 11.82 percent, respectively. Phylogenetic analysis of both the L10/L12 rDNA sequences and the L10 amino acid sequences clustered the Kenyan strains of the 'Candidatus Liberibacter' species with members of alpha subdivision of proteobacteria.


Assuntos
DNA Ribossômico/agonistas , DNA Ribossômico/genética , Proteobactérias/enzimologia , Proteobactérias/metabolismo , Proteínas Ribossômicas , Análise de Sequência de DNA/métodos , Análise de Sequência de DNA , Eletroforese em Gel de Ágar , Quênia , Filogenia
11.
Braz. j. microbiol ; 40(1): 26-30, Jan.-Mar. 2009. ilus, tab
Artigo em Inglês | LILACS | ID: lil-513111

RESUMO

Various genotoxic textile dyes, xenobiotics, substrates (10 µM) and agrochemicals (100 µg/ml) were tested for enhancement of alkalophilic laccase activity inã-proteobacterium JB. Neutral Red, Indigo Carmine, Naphthol Base Bordears and Sulphast Ruby dyes increased the activity by 3.7, 2.7, 2.6 and 2.3 fold respectively. Xenobiotics/substrates like p-toluidine, 8-hydroxyquinoline and anthracine increased it by 3.4, 2.8 and 2.3 fold respectively. Atrazine and trycyclozole pesticides enhanced the activityby 1.95 and 1.5 fold respectively.


Vários corantes têxteis genotóxicos, xenobióticos, substratos (10 mM) e agroquímicos (100 mM/mL) foram testados quanto ao aumento da atividade de lacase em ã-Proteobacterium JB. Os corantes Neutral Red, Indigo Carmine, Naphtol Base Bordears e Sulphast Ruby aumentaram a atividade em 3,7, 2,7, 2,6 e 2,3 vezes, respectivamente. Xenobióticos/substratos como p-toluidina, 8-hidroxiquinolina e antracina aumentaram a atividade em 3,4, 2,8 e 2,3 vezes, respectivamente. Atrazina e pesticidas triciclozol aumentaram a atividade em 1,95 e 1,5 vezes, respectivamente.


Assuntos
Corantes/análise , Lacase/análise , Mutagênicos/análise , Proteobactérias/enzimologia , Xenobióticos/análise , Ativação Enzimática , Métodos , Métodos
12.
Electron. j. biotechnol ; 11(5): 5-6, Dec. 2008. ilus, tab
Artigo em Inglês | LILACS | ID: lil-538011

RESUMO

s-Triazine-degrading bacterial strains were isolated from long-term simazine-treated agricultural soils of central Chile. The number of culturable heterotrophic bacteria of these agricultural soils (7 x 10(6) CFU/g of dry soil) was not affected by simazine application on field. The simazine-degrading bacterial strains P51, P52 and C53 were isolated by enrichment in minimal medium using simazine as the sole nitrogen source. Resting cells of strains P51 and P52 degraded >80 percent of simazine within 48 hrs, whereas strain C53 was able to remove >60 percent of the herbicide. The atzA and atzD genes of the s-triazine upper and lower catabolic pathways were detected in strains P51 and C53, while only atzD gene was observed in strain P52. To compare the bacterial 16S rRNA gene sequence structure, ARDRA were performed using the restriction enzymes Msp1 and Hha1. ARDRA indicated that strain P52 was a different ribotype than C53 and P51 strains. For further characterization the novel isolates were identified by 16S rRNA gene sequencing. Strains C53 and P51 belong to the genus Stenotrophomonas and the strain P52 belongs to the genus Arthrobacter . s -Triazine-degrading bacterial strains isolated from contaminated soils could be used as biocatalysts for bioremediation of these herbicides.


Assuntos
Simazina/administração & dosagem , Simazina/uso terapêutico , Stenotrophomonas/enzimologia , Triazinas/administração & dosagem , Triazinas/uso terapêutico , Cultivos Agrícolas , Arthrobacter/enzimologia , Biodegradação Ambiental , Chile , Herbicidas/administração & dosagem , Herbicidas/uso terapêutico , Proteobactérias/enzimologia
13.
An. acad. bras. ciênc ; 77(3): 549-579, Sept. 2005.
Artigo em Inglês | LILACS | ID: lil-406231

RESUMO

A presente revisão aborda a história da Fixação Biológica de Nitrogênio (FBN) em Gramíneas no Brasil, procurando mostrar a evolução da pesquisa na área iniciada a mais de 40 anos sob a liderança da pesquisadora Johanna Döbereiner. Um aspecto marcante deste período foi a descoberta de diversas bactérias fixadoras de nitrogênio atmosférico tais com as rizosféricas (Beijerinckia fluminensis e Azotobacter paspali), associativas (Azospirillum lipoferum, A. brasilense, A. amazonense) e as endofíticas (Herbaspirillum seropedicae, H. rubrisubalbicans, Gluconacetobacter diazotrophicus, Burkholderia brasilensis e B. tropica). O papel destas bactérias diazotróficas em associação com as gramíneas, especialmente os cereais, tem sido estudado e muito se avançou sobre os aspectos ecológicos, fisiológicos, bioquímicos e genéticos. Os mecanismos de colonização e infecção dos tecidos das plantas foram melhor entendidos e a contribuição da FBN para o sistema solo-planta foi determinado. Estudos de inoculação de cereais com bactérias diazotróficas, têm mostrado que as endofíticas têm um maior potencial de contribuição da FBN e que o genótipo da planta influencia na associação da planta/bactéria. Os avanços alcançados apontam para uma maior exploração e entendimento desta associação endofítica. Os programas de sequenciamento do genoma: RIOGENE (Gluconacetobacter diazotrophicus) e GENOPAR (Herbaspirillum seropedicae) mostram a importância da FBN no Brasil e devem permitir que o país continue na fronteira do conhecimento em relação ao processo de FBN em gramíneas.


Assuntos
Fixação de Nitrogênio/fisiologia , Poaceae/fisiologia , Proteobactérias/metabolismo , Brasil , Genótipo , Fixação de Nitrogênio/genética , Raízes de Plantas/microbiologia , Raízes de Plantas/fisiologia , Poaceae/microbiologia , Proteobactérias/genética
14.
Biol. Res ; 38(2/3): 283-297, 2005. ilus, tab
Artigo em Inglês | LILACS | ID: lil-424732

RESUMO

The genome of the acidophilic, proteobacterium Acidithiobacillus ferrooxidans, contains linked but divergently oriented genes, termed afeI and afeR, whose predicted protein products are significantly similar to the LuxI and LuxR families of proteins. A possible promoter and Lux box are predicted upstream of afeI. A cloned copy of afeI, expressed in E. coli, encodes an enzyme that catalyzes the production of a diffusible compound identified by gas chromatography and mass spectrometry as an unsubstituted N-acyl homoserine lactone (AHL) of chain length C14. This AHL can be detected by a reporter strain of Sinorhizobium meliloti Rm41 suggesting that it is biologically active. The reporter strain also responds to extracts of the supernatant of A. ferrooxidans grown to early stationary phase in sulfur medium indicating that a diffusible AHL is produced by this microorganism. Semi-quantitative RT-PCR experiments indicate that afeI and afeR are expressed maximally in early stationary phase and are more expressed when A. ferrooxidans is grown in sulfur- rather than iron-containing medium. Given the predicted amino acid sequence and functional properties of AfeI and AfeR it is proposed that A. ferrooxidans has a quorum sensing system similar to the LuxI-LuxR paradigm.


Assuntos
Acidithiobacillus thiooxidans , Acidithiobacillus thiooxidans/química , Proteobactérias , Proteobactérias/química , Genoma Bacteriano , /análise , /biossíntese , /química , /síntese química , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase
15.
Rev. biol. trop ; 49(3/4): 1213-1222, Sep.-Dec. 2001.
Artigo em Espanhol | LILACS | ID: lil-333064

RESUMO

Bacteria from several groups of marine organisms were isolated and, using direct antibiograms, identified those that produce antibacterial substances, using a human pathogenic strain of Staphylococcus aureus ATCC6538 as revealing microorganism. Bacteria which produce substances that inhibited S. aureus growth were identified through morphological, physiological and biochemical tests. Out of 290 bacteria, 54 (18.6) inhibited the growth of S. aureus, but only 27 survived for identification. Bivalves, sponges and corals were the most represented from which 41.2, 33.3 and 29.7, respectively, produced antibacterial substances of the isolated bacteria in each group. The marine species with highest proportions of these bacteria were the hard coral Madracis decactis (62.5), the sponges Cliona sp. (57.1) and the octocoral Plexaura flexuosa (50.0). Out of the 27 strains that produced antibacterial substances, 51.8 were Aeromonas spp. and 14.8 Vibrio spp. Marine bacteria that produce antibacterial substances are abundant, most belong in the Vibrionacea group and were isolated mainly from corals and bivalve mollusks.


Assuntos
Animais , Água do Mar/microbiologia , Antibacterianos/biossíntese , Bactérias Gram-Negativas/metabolismo , Invertebrados , Staphylococcus aureus , Antibiose , Antibacterianos/farmacologia , Bivalves , Cnidários , Inibidores do Crescimento , Poríferos/microbiologia , Proteobactérias/metabolismo , Staphylococcus aureus , Microbiologia da Água
16.
São Paulo; CVE; 1986. 95 p. ilus, tab, graf.
Monografia em Português | LILACS, Sec. Est. Saúde SP, SESSP-CTDPROD, Sec. Est. Saúde SP, SESSP-CVEPROD, Sec. Est. Saúde SP, SESSP-ILSLACERVO, Sec. Est. Saúde SP | ID: lil-463393
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...