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1.
Microbiol Resour Announc ; 12(9): e0036323, 2023 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-37548468

RESUMO

The complete genome sequences of five Escherichia coli strains with probiotic attributes were determined, including strain A0 34/86, a component of the probiotic product Colinfant New Born, and strains H22, 582, B771, and B1172 with published probiotic potential. The size of sequenced genomes ranged from 5,092 to 5,408 kb.

2.
Environ Int ; 146: 106234, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33181412

RESUMO

In nature, arsenic (As) and iron (Fe) biotransformation are interconnected, influencing local As mobility and toxicity. While As- or Fe-metabolizing microorganisms are widely documented, knowledge concerning their cycling genes, associated with geophysicochemical data and taxonomic distribution, remains scarce. We performed a meta-analysis to explore the distribution and environmental importance of As- and Fe-redox genes (AsRGs and FeRGs) and predict their significant correlations and hosts. The most abundant and ubiquitous AsRGs and FeRGs were arsC and ccoN, respectively. The ccoN gene had the highest frequency at pH ≥ 9.1, in which dissolved Fe(II) is scarce, possibly contributing to enhanced host survival. Fe(III) oxidation genes iro and ccoN appear to be associated with As(V) detoxification in mesophilic environments. No correlation was observed between Fe(III) reduction gene omcB and arsenate reductase genes. Cytochromes with putative roles in Fe-redox reactions were identified (including yceJ and fbcH) and were significantly correlated with As(V) reduction genes under diverse geophysicochemical conditions. The taxonomies of AsRGs and FeRGs-carrying contigs revealed great diversity, among which various, such as Chlamydea (arsC) and Firmicutes (omcB), were previously undescribed. Nearly all (98.9%) of the AsRGs and FeRGs were not carried by any plasmid sequences. This meta-analysis expands our understanding of the global environmental, taxonomic and functional microbiome involved in As- and Fe-redox transformations. Moreover, these findings should help guide studies on putative in vivo functional roles of cytochromes in Fe-redox pathways.


Assuntos
Arsênio , Microbiota , Arsênio/toxicidade , Biotransformação , Ferro , Oxirredução
3.
Sci Rep ; 10(1): 22312, 2020 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-33339861

RESUMO

Plants may contain beneficial or potentially dangerous substances to humans. This study aimed to prepare and evaluate a new drug delivery system based on a glass-ionomer-Brazilian pepper extract composite, to check for its activity against pathogenic microorganisms of the oral cavity, along with its in vitro biocompatibility. The ethanolic Brazilian pepper extract (BPE), the glass-ionomer cement (GIC) and the composite GIC-BPE were characterized by scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and thermal analysis. The BPE compounds were identified by UPLC-QTOF-MS/MS. The release profile of flavonoids and the mechanical properties of the GIC-BPE composite were assessed. The flavonoids were released through a linear mechanism governing the diffusion for the first 48 h, as evidenced by the Mt/M∞ relatively to [Formula: see text], at a diffusion coefficient of 1.406 × 10-6 cm2 s-1. The ATR-FTIR analysis indicated that a chemical bond between the GIC and BPE components may have occurred, but the compressive strength of GIC-BPE does not differ significantly from that of this glass-ionomer. The GIC-BPE sample revealed an ample bacterial activity at non-cytotoxic concentrations for the human fibroblast MRC-5 cells. These results suggest that the prepared composite may represent an alternative agent for endodontic treatment.


Assuntos
Anacardiaceae/química , Cimentos de Ionômeros de Vidro/síntese química , Boca/efeitos dos fármacos , Extratos Vegetais/química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Brasil , Força Compressiva , Frutas/química , Cimentos de Ionômeros de Vidro/química , Cimentos de Ionômeros de Vidro/farmacologia , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Boca/química , Boca/microbiologia , Extratos Vegetais/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Chemosphere ; 253: 126584, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32278186

RESUMO

Studies on disturbance events in riverine systems caused by environmental disasters and their effects on microbial diversity are scarce. Here, we evaluated the impact of the collapse of an iron ore dam holding approximately 50 million cubic meters of waste on both water and sediment microbiomes by deeply sequencing the 16S rRNA gene. Samples were taken from two impacted rivers and one reference river 7, 30 and 150 days postdisturbance. The impacted community structure changed greatly over spatiotemporal scales, being less diverse and more uneven, particularly on day 7 for the do Carmo River (the closest to the dam). However, the reference community structure remained similar between sampling events. Moreover, the impacted sediments were positively correlated with metals. The taxa abundance varied greatly over spatiotemporal scales, allowing for the identification of several potential bioindicators, e.g., Comamonadaceae, Novosphingobium, Sediminibacterium and Bacteriovorax. Our results showed that the impacted communities consisted mostly of Fe(II) oxidizers and Fe(III) reducers, aromatic compound degraders and predator bacteria. Network analysis showed a highly interconnected microbiome whose interactions switched from positive to negative or vice versa between the impacted and reference communities. This work revealed potential molecular signatures associated with the rivers heavily impacted by metals that might be useful sentinels for predicting riverine health.


Assuntos
Monitoramento Ambiental , Microbiota , Mineração , Rios/microbiologia , Poluentes Químicos da Água/análise , Bactérias/genética , Bacteroidetes/genética , Compostos Férricos/análise , Sedimentos Geológicos/química , RNA Ribossômico 16S/genética , Rios/química , Esgotos/análise , Tsunamis
5.
Front Microbiol ; 11: 549254, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33584554

RESUMO

The rapid emergence of multidrug-resistant (MDR) bacteria is a global health problem. Mobile genetic elements like conjugative plasmids, transposons, and integrons are the major players in spreading resistance genes in uropathogenic Escherichia coli (UPEC) pathotype. The E. coli BH100 strain was isolated from the urinary tract of a Brazilian woman in 1974. This strain presents two plasmids carrying MDR cassettes, pBH100, and pAp, with conjugative and mobilization properties, respectively. However, its transposable elements have not been characterized. In this study, we attempted to unravel the factors involved in the mobilization of virulence and drug-resistance genes by assessing genomic rearrangements in four BH100 sub-strains (BH100 MG2014, BH100 MG2017, BH100L MG2017, and BH100N MG2017). Therefore, the complete genomes of the BH100 sub-strains were achieved through Next Generation Sequencing and submitted to comparative genomic analyses. Our data shows recombination events between the two plasmids in the sub-strain BH100 MG2017 and between pBH100 and the chromosome in BH100L MG2017. In both cases, IS3 and IS21 elements were detected upstream of Tn21 family transposons associated with MDR genes at the recombined region. These results integrated with Genomic island analysis suggest pBH100 might be involved in the spreading of drug resistance through the formation of resistance islands. Regarding pathogenicity, our results reveal that BH100 strain is closely related to UPEC strains and contains many IS3 and IS21-transposase-enriched genomic islands associated with virulence. This study concludes that those IS elements are vital for the evolution and adaptation of BH100 strain.

6.
Sci Total Environ ; 672: 990-1003, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30981171

RESUMO

Bacterioplankton communities have a pivotal role in the global carbon cycle. Still the interaction between microbial community and dissolved organic matter (DOM) in freshwater ecosystems remains poorly understood. Here, we report results from a 12-day mesocosm study performed in the epilimnion of a tropical lake, in which inorganic nutrients and allochthonous DOM were supplemented under full light and shading. Although the production of autochthonous DOM triggered by nutrient addition was the dominant driver of changes in bacterial community structure, temporal covariations between DOM optical proxies and bacterial community structure revealed a strong influence of community shifts on DOM fate. Community shifts were coupled to a successional stepwise alteration of the DOM pool, with different fractions being selectively consumed by specific taxa. Typical freshwater clades as Limnohabitans and Sporichthyaceae were associated with consumption of low molecular weight carbon, whereas Gammaproteobacteria and Flavobacteria utilized higher molecular weight carbon, indicating differences in DOM preference among clades. Importantly, Verrucomicrobiaceae were important in the turnover of freshly produced autochthonous DOM, ultimately affecting light availability and dissolved organic carbon concentrations. Our findings suggest that taxonomically defined bacterial assemblages play definite roles when influencing DOM fate, either by changing specific fractions of the DOM pool or by regulating light availability and DOC levels.


Assuntos
Bactérias/crescimento & desenvolvimento , Monitoramento Ambiental , Substâncias Húmicas/análise , Lagos/microbiologia , Microbiologia da Água , Poluentes da Água/análise , Organismos Aquáticos , Carbono , Ecossistema , Lagos/química , Clima Tropical
7.
Microb Ecol ; 78(3): 575-588, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30706113

RESUMO

Water hyacinth (WH), a large floating plant, plays an important role in the biogeochemistry and ecology of many freshwaters globally. Its biogeochemical impact on wetland functioning is strongly mediated by the microbiome associated with its roots. However, little is known about the structure and function of this WH rhizobiome and its relation to wetland ecosystem functioning. Here, we unveil the core and transient rhizobiomes of WH and their key biogeochemical functions in two of the world's largest wetlands: the Amazon and the Pantanal. WH hosts a highly diverse microbial community shaped by spatiotemporal changes. Proteobacteria lineages were most common, followed by Actinobacteria and Planctomycetes. Deltaproteobacteria and Sphingobacteriia predominated in the core microbiome, potentially associated with polysaccharide degradation and fermentation of plant-derived carbon. Conversely, a plethora of lineages were transient, including highly abundant Acinetobacter, Acidobacteria subgroup 6, and methanotrophs, thus assuring diverse taxonomic signatures in the two different wetlands. Our findings point out that methanogenesis is a key driver of, and proxy for, community structure, especially during seasonal plant decline. We provide ecologically relevant insights into the WH microbiome, which is a key element linking plant-associated carbon turnover with other biogeochemical fluxes in tropical wetlands.


Assuntos
Bactérias/isolamento & purificação , Bactérias/metabolismo , Carbono/metabolismo , Eichhornia/microbiologia , Microbiota , Bactérias/classificação , Bactérias/genética , DNA Bacteriano/genética , Ecossistema , Nutrientes/metabolismo , Filogenia , RNA Ribossômico 16S/genética
8.
Sci Rep ; 8(1): 8783, 2018 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-29884862

RESUMO

Leprosy is a chronic infectious peripheral neuropathy that is caused by Mycobacterium leprae, and the skin is one of its preferred target sites. However, the effects of this infection on the skin microbiome remain largely unexplored. Here, we characterize and compare the lesional and non-lesional skin microbiomes of leprosy patients and healthy individuals through the deep sequencing of 16 S rRNA genes. Additionally, a subset of patients was monitored throughout the multi-drug therapy to investigate its effect on the leprous skin microbiome. Firmicutes-associated OTUs (primarily Staphylococcus) prevailed in healthy individuals. By contrast, Firmicutes was underrepresented and Proteobacteria was enriched in the patients' skin, although a single dominant taxon has not been observed at a finer taxonomic resolution. These differences can be explained by the significant decrease in Staphylococcus and Streptococcus as well as the enrichment in Brevundimonas. The overrepresentation of Micrococcus in patients is also remarkable. Genus-level compositional profiles revealed no significant intrapersonal difference between lesional and non-lesional sites. Treatment-associated changes indicated a loss of diversity and a shift in the community composition, with stronger impacts on the OTUs that are considered indigenous bacteria. Therefore, the molecular signatures associated with leprosy identified herein might be of importance for early diagnostics.


Assuntos
Bactérias/isolamento & purificação , Hanseníase/microbiologia , Microbiota , Pele/microbiologia , Antibacterianos/uso terapêutico , Bactérias/classificação , Bactérias/genética , Brasil/epidemiologia , Firmicutes/classificação , Firmicutes/genética , Firmicutes/isolamento & purificação , Humanos , Hanseníase/tratamento farmacológico , Hanseníase/epidemiologia , Microbiota/efeitos dos fármacos , Mycobacterium leprae/efeitos dos fármacos , Estudos Prospectivos , Proteobactérias/classificação , Proteobactérias/genética , Proteobactérias/isolamento & purificação
9.
Water Res ; 132: 79-89, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29306702

RESUMO

Gut microbiota exerts a fundamental role on host physiology, and how extrinsic perturbations influence its composition has been increasingly examined. However, the effect of drinking water on gut microbiota is still poorly understood. In this study, we explored the response of mouse gut bacterial community (fecal and mucosa-adhered) to the ingestion of different types of drinking water. The experimental cohort was divided according to different water sources into four groups of mice that consumed autoclaved tap water (control group), water collected directly from a drinking water treatment plant, tap water, and commercial bottled mineral water. Differences among groups were observed, especially related to control group, which exhibited the smallest intra-group variation, and the largest distance from test groups on the last experimental day. Clinically important taxa, such as Acinetobacter and Staphylococcus, increased in feces of mice that drank tap water and in mucosa-adhered samples of animals from disinfected and tap water groups. Furthermore, statistical analyses showed that both time elapsed between samplings and water type significantly influenced the variation observed in the samples. Our results reveal that drinking water potentially affects gut microbiota composition. Additionally, the increase of typical drinking water clinically relevant and antibiotic resistance-associated bacteria in gut microbiota is a cause of concern.


Assuntos
Bactérias/classificação , Água Potável , Microbioma Gastrointestinal , Águas Minerais , Animais , Desinfecção , Fezes/microbiologia , Feminino , Camundongos Endogâmicos BALB C , Purificação da Água , Abastecimento de Água
10.
Sci Rep ; 7(1): 11231, 2017 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-28894204

RESUMO

Bacteria are essential in arsenic cycling. However, few studies have addressed 16S rRNA and arsenic-related functional gene diversity in long-term arsenic-contaminated tropical sediment. Here, using culture-based, metagenomic and computational approaches, we describe the diversity of bacteria, genes and enzymes involved in AsIII and AsV transformation in freshwater sediment and in anaerobic AsIII- and AsV-enrichment cultures (ECs). The taxonomic profile reveals significant differences among the communities. Arcobacter, Dechloromonas, Sedimentibacter and Clostridium thermopalmarium were exclusively found in ECs, whereas Anaerobacillus was restricted to AsV-EC. Novel taxa that are both AsV-reducers and AsIII-oxidizers were identified: Dechloromonas, Acidovorax facilis, A. delafieldii, Aquabacterium, Shewanella, C. thermopalmarium and Macellibacteroides fermentans. Phylogenic discrepancies were revealed among the aioA, arsC and arrA genes and those of other species, indicating horizontal gene transfer. ArsC and AioA have sets of amino acids that can be used to assess their functional and structural integrity and familial subgroups. The positions required for AsV reduction are conserved, suggesting strong selective pressure for maintaining the functionality of ArsC. Altogether, these findings highlight the role of freshwater sediment bacteria in arsenic mobility, and the untapped diversity of dissimilatory arsenate-reducing and arsenate-resistant bacteria, which might contribute to arsenic toxicity in aquatic environments.


Assuntos
Arsênio/metabolismo , Bactérias/classificação , Água Doce/microbiologia , Variação Genética , Sedimentos Geológicos/microbiologia , Redes e Vias Metabólicas/genética , Poluentes Químicos da Água/metabolismo , Anaerobiose , Bactérias/genética , Bactérias/isolamento & purificação , Biotransformação , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Enzimas/genética , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
11.
J Med Microbiol ; 66(5): 577-583, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28485709

RESUMO

PURPOSE: Class 1 integrons are among the main vehicles that facilitate the spread of antibiotic-resistance genes, with serious public health consequences. The aim of this cross-sectional study was to investigate the presence of class 1 integrons and to characterize their variable regions, as well as the antimicrobial resistance profiles and phylogenetic groups of a collection of Escherichia coli isolates recovered from healthy subjects (n=42) and those with urinary infection (n=40). METHODOLOGY: The methods used included PCR, sequencing and antimicrobial susceptibility testing. RESULTS: PCR screening for the integrase gene (intI1) revealed a higher incidence of class 1 integrons in uropathogenic E. coli (65 %, UPEC) than in commensal isolates (11.9 %). Eight of 31 intI1-positive isolates, all of them UPEC, harboured empty integrons. The variable regions of the other 23 contained gene cassettes encoding resistance to ß-lactams (blaOXA-1), aminoglycosides (aadA1 and aadA5), trimethoprim (dfrA1 and dfrA17) and an ORF. To our knowledge this is the first report of an ORF identified as a putative phage tail protein associated with a class 1 integron. The aadA1 and dfrA17-addA5 arrays prevailed in commensal E. coli and UPEC, respectively. UPEC isolates were highly resistant to the antimicrobials tested, in contrast to commensal isolates. The E. coli isolates carrying gene cassettes associated with class 1 integrons were found to be unrelated to any phylogroup or multiresistance. CONCLUSION: Co-resistance to clinically relevant fluoroquinolone and trimethoprim-sulfamethazole in all UPEC isolates is a cause for concern. These results expand the current knowledge of gene cassettes in both commensal and pathogenic E. coli.


Assuntos
Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Escherichia coli/genética , Integrons , Infecções Urinárias/microbiologia , Escherichia coli Uropatogênica/genética , Antibacterianos/farmacologia , Estudos Transversais , Farmacorresistência Bacteriana/genética , Escherichia coli/efeitos dos fármacos , Infecções por Escherichia coli/epidemiologia , Fezes/microbiologia , Humanos , Fenótipo , Filogenia , Reação em Cadeia da Polimerase , Simbiose/genética , Escherichia coli Uropatogênica/efeitos dos fármacos
12.
FEMS Microbiol Ecol ; 93(1)2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-27797965

RESUMO

Bacteria are highly important for the cycling of organic and inorganic matter in freshwater environments; however, little is known about the diversity of bacterioplankton in tropical systems. Studies on carbon and nutrient cycling in tropical lakes suggest a very different seasonality from that of temperate climates. Here, we used 16S rRNA gene next-generation sequencing (NGS) to investigate seasonal changes in bacterioplankton communities of two tropical lakes, which differed in trophic status and mixing regime. Our findings revealed seasonally and depth-wise highly dynamic bacterioplankton communities. Differences in richness and structure appeared strongly related to the physicochemical characteristics of the water column, especially phosphate, pH and oxygen. Bacterioplankton communities were dominated by common taxonomic groups, such as Synechococcus and Actinobacteria acI, as well as rare and poorly characterized taxa such as 'Candidatus Methylacidiphilum' (Verrucomicrobia). Stratification and oxygen depletion during the rainy season promoted the occurrence of anoxygenic phototrophic and methanotrophic bacteria important for carbon and nutrient cycling. Differences in lake mixing regime were associated with seasonal beta diversity. Our study is the first attempt to use NGS for cataloging the diversity of bacterioplankton communities in Brazilian lakes and thus contributes to the ongoing worldwide endeavor to characterize freshwater lake bacterioplankton signatures.


Assuntos
Actinobacteria/isolamento & purificação , Bactérias/classificação , Bactérias/isolamento & purificação , Lagos/microbiologia , Synechococcus/isolamento & purificação , Actinobacteria/genética , Bactérias/genética , Brasil , Florestas , Lagos/química , Filogenia , Plâncton/classificação , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Synechococcus/genética
13.
Water Res ; 110: 27-37, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-27984803

RESUMO

Wastewater treatment plants (WWTPs) harbor bacteria and antimicrobial resistance genes, favoring gene exchange events and resistance dissemination. Here, a culture-based and metagenomic survey of qnrA, qnrB, qnrS, and aac(6')-Ib genes from raw sewage (RS) and activated sludge (AS) of a full-scale municipal WWTP was performed. A total of 96 bacterial isolates were recovered from nalidixic acid-enrichment cultures. Bacteria harboring the aac(6')-Ib gene predominated in RS, whereas qnrS-positive isolates were specific to AS. Novel qnrS- and aac(6')-Ib-cr positive species were identified: Morganella morganii, Providencia rettgeri, and Pseudomonas guangdongensis (qnrS), and Alcaligenes faecalis and P. rettgeri (aac(6')-Ib-cr). Analysis of qnrS and aac(6')-Ib sequences from isolates and clone libraries suggested that the diversity of qnrS is wider than that of aac(6')-Ib. A large number of amino acid mutations were observed in the QnrS and AAC(6')-Ib proteins at previously undetected positions, whose structural implications are not clear. An accumulation of mutations at the C72, Q73, L74, A75 and M76 positions of QnrS, and D181 of AAC(6')-Ib might be important for resistance. These findings add significant information on bacteria harboring qnrS and aac(6')-Ib genes, and the presence of novel mutations that may eventually emerge in clinical isolates.


Assuntos
Escherichia coli/isolamento & purificação , Esgotos , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Fluoroquinolonas , Testes de Sensibilidade Microbiana , Mutação , Plasmídeos/efeitos dos fármacos , Quinolonas
14.
Chemosphere ; 161: 266-273, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27441985

RESUMO

Bacteria from aquatic ecosystems significantly contribute to biogeochemical cycles, but details of their community structure in tropical mining-impacted environments remain unexplored. In this study, we analyzed a bacterial community from circumneutral-pH tropical stream sediment by 16S rRNA and shotgun deep sequencing. Carrapatos stream sediment, which has been exposed to metal stress due to gold and iron mining (21 [g Fe]/kg), revealed a diverse community, with predominance of Proteobacteria (39.4%), Bacteroidetes (12.2%), and Parcubacteria (11.4%). Among Proteobacteria, the most abundant reads were assigned to neutrophilic iron-oxidizing taxa, such as Gallionella, Sideroxydans, and Mariprofundus, which are involved in Fe cycling and harbor several metal resistance genes. Functional analysis revealed a large number of genes participating in nitrogen and methane metabolic pathways despite the low concentrations of inorganic nitrogen in the Carrapatos stream. Our findings provide important insights into bacterial community interactions in a mining-impacted environment.


Assuntos
Bactérias/metabolismo , Redes e Vias Metabólicas/efeitos dos fármacos , Mineração , Rios , Microbiologia da Água , Bactérias/classificação , Bactérias/genética , Bacteroidetes/classificação , Bacteroidetes/genética , Bacteroidetes/metabolismo , Brasil , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Ferro/análise , Ferro/metabolismo , Metagenômica , Filogenia , Proteobactérias/classificação , Proteobactérias/genética , Proteobactérias/metabolismo , RNA Ribossômico 16S/genética , Rios/química , Rios/microbiologia , Clima Tropical , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo
15.
Extremophiles ; 20(3): 283-9, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26961777

RESUMO

The integron-gene cassette system has typically been associated with antibiotic-resistant pathogens. However, the diversity of gene cassettes and the abundance of class 1 integrons outside of the clinical context are not fully explored. Primers targeting the conserved segments of attC recombination sites were used to amplify gene cassettes from the sediment of the Mina stream, which exhibited a higher degree of stress to metal pollution in the dry season than the rainy season. Of the 143 total analyzed sequences, 101 had no matches to proteins in the database, where cassette open reading frames could be identified by homology with database entries. There was a predominance of sequences encoding essential cellular functions. Each season that was sampled yielded a specific pool of gene cassettes. Real-time PCR revealed that 8.5 and 41.6 % of bacterial cells potentially harbored a class 1 integron in the rainy and dry seasons, respectively. In summary, our findings demonstrate that most of the gene cassettes have no ascribable function and, apparently, historically metal-contaminated sediment favors the maintenance of bacteria containing the intI1 gene. Thus, the diversity of gene cassettes is far from being fully explored deserving further attention.


Assuntos
Poluição Ambiental , Genes Bacterianos , Variação Genética , Sedimentos Geológicos/microbiologia , Integrases/genética , Microbiota , Arsênio/análise , Bacteroidetes/genética , Bacteroidetes/isolamento & purificação , Sedimentos Geológicos/química , Ferro/análise , Proteobactérias/genética , Proteobactérias/isolamento & purificação
16.
Chemosphere ; 146: 519-25, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26741558

RESUMO

Biomethanization entails a good means to reduce the organic fraction (OF) derived from municipal solid wastes (MSW). The bacterial diversity of a full scale MSW anaerobic reactor located in Madrid (Spain) was investigated using high-throughput 454 pyrosequencing. Even though the proteolytic bacteria prevailed throughout all of the process, community shifts were observed from the start-up to the steady-state conditions, with an increasing biodiversity displayed over time. The Bacteroidetes and the Firmicutes were the majority phyla: 55.1 and 40.2% (start-up) and 18.7 and 78.7 (steady-state) of the total reads. The system's lack of evenness remains noteworthy as the sequences affiliated to the proteolytic non-saccharolytic Proteiniphylum, Gallicola and Fastidiosipila genera, together with the saccharolytic Saccharofermentans, were predominant on the system and this predominance appears to correlate with the presence of a high ammonium concentration. The 454 pyrosequencing revealed a great diversity of rare organisms which seemingly do not sustain any metabolic roles in the course of the OF-MSW degradation. However, this scarce and unique microbiota can confer great resilience to the system as a buffer against nutritional and environmental changing conditions, thus opening the door to increase the current knowledge about the bacterial community dynamics taking place during MSW treatment processes.


Assuntos
Bacteroidetes/classificação , Bacteroidetes/crescimento & desenvolvimento , Reatores Biológicos/microbiologia , Firmicutes/classificação , Firmicutes/crescimento & desenvolvimento , Eliminação de Resíduos/métodos , Anaerobiose , Bacteroidetes/genética , Biodiversidade , Firmicutes/genética , Sequenciamento de Nucleotídeos em Larga Escala , RNA Ribossômico 16S/genética , Análise de Sequência de RNA , Espanha
17.
Food Chem ; 192: 306-12, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26304352

RESUMO

Purification and bioassay-guided fractionation were employed to isolate proanthocyanidins with antioxidant activity from peanut skin (Arachis hypogaea Runner 886). The crude extract was prepared with acetone (60% v/v) and purified using chromatographic methods, including a semipreparative HPLC technique. As a result, two proanthocyanidins were isolated and identified using NMR, epicatechin-(2 ß â†’ O → 7, 4 ß â†’ 8)-catechin (proanthocyanidin A1) and epicatechin-(ß â†’ 2 O → 7, 4 ß â†’ 8)-epicatechin (proanthocyanidin A2). Despite the structural similarity, differences were observed in their antioxidant activity. Proanthocyanidin A1 proved to be more active, with EC50 value for DPPH radical scavenging of 18.25 µg/mL and reduction of Fe(3+)-TPTZ complex of 7.59 mmol/g, higher than that of synthetic antioxidant BHT. This compound evaluated by ABTS(+) was similar to that of natural quercetin. Therefore, peanut skin is an important source of bioactive compounds that may be used as a mild antioxidant for food preservation.


Assuntos
Antioxidantes/análise , Arachis/química , Análise de Alimentos/métodos , Proantocianidinas/análise , Sementes/química , Bioensaio , Catequina/análise , Cromatografia Líquida de Alta Pressão , Extratos Vegetais/química , Quercetina/análise
18.
Braz. arch. biol. technol ; 59: e16160287, 2016. tab, graf
Artigo em Inglês | LILACS | ID: biblio-951361

RESUMO

ABSTRACT Although endophytic bacteria impact the health, and ultimately the fitness, of their hosts, our understanding of the diversity of endophytic species remains limited. Here we report on the endophytic microbiota inhabiting the roots, healthy leaves and leaves attacked by a gall-inducing insect of Baccharis dracunculifolia, a species of major economic relevance in South America, using 16S rRNA gene new generation sequencing. Rhodoplanes and Nitrospira were well represented in the communities of roots and leaves; known to be important for nitrogen cycling. The difference in bacterial diversity between healthy and galled leaves was not pronounced. The leaves seem to harbor specialized bacteria with high tolerances to abiotic stresses such as wide variation in temperature, low humidity, shallow and nutrient-poor soils and high solar irradiation. These findings suggest taxon-specific ecological niches in the leaves and roots, which may be the result of different physicochemical characteristics between these structures. This study provides a basis for further investigations and adds significant new information to the current knowledge of the endophytic bacterial composition in B. dracunculifolia.

19.
Front Microbiol ; 6: 898, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26379659

RESUMO

Ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) are a diverse and functionally important group in the nitrogen cycle. Nevertheless, AOA and AOB communities driving this process remain uncharacterized in tropical freshwater sediment. Here, the effect of human settlement on the AOA and AOB diversity and abundance have been assessed by phylogenetic and quantitative PCR analyses, using archaeal and bacterial amoA and 16S rRNA genes. Overall, each environment contained specific clades of amoA and 16S rRNA genes sequences, suggesting that selective pressures lead to AOA and AOB inhabiting distinct ecological niches. Human settlement activities, as derived from increased metal and mineral nitrogen contents, appear to cause a response among the AOB community, with Nitrosomonas taking advantage over Nitrosospira in impacted environments. We also observed a dominance of AOB over AOA in mining-impacted sediments, suggesting that AOB might be the primary drivers of ammonia oxidation in these sediments. In addition, ammonia concentrations demonstrated to be the driver for the abundance of AOA, with an inversely proportional correlation between them. Our findings also revealed the presence of novel ecotypes of Thaumarchaeota, such as those related to the obligate acidophilic Nitrosotalea devanaterra at ammonia-rich places of circumneutral pH. These data add significant new information regarding AOA and AOB from tropical freshwater sediments, albeit future studies would be required to provide additional insights into the niche differentiation among these microorganisms.

20.
World J Microbiol Biotechnol ; 31(11): 1793-800, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26318306

RESUMO

The purpose of this work was to evaluate the antileishmanial activity of endophytic fungi isolated from leaves of Vernonia polyanthes plant and their prospective use in the discovery of bioactive compounds. Sixteen endophytes were isolated by using potato dextrose agar medium and submitted to cultivation in rice medium. The fungal cultures were extracted with ethanol and used as crude extracts for testing their antileishmanial activity. The most active ethanol extract was obtained from P2-F3 strain, which was identified as Cochliobolus sativus by ITS rRNA gene sequence data. Followed by a bioassay-guided fractionation, the cochlioquinone A, isocochlioquinone A and anhydrocochlioquinone A compounds were isolated from the crude extracts and demonstrated to inhibit the parasites. From the present work, it is possible to conclude that endophytic fungi derived from medicinal plant V. polyanthes may be considered promising source for the discovery of bioactive compounds.


Assuntos
Ascomicetos/classificação , Etanol/isolamento & purificação , Leishmania/efeitos dos fármacos , Tripanossomicidas/farmacologia , Vernonia/microbiologia , Ascomicetos/química , Ascomicetos/genética , DNA Fúngico/análise , DNA Ribossômico/análise , Endófitos/química , Endófitos/classificação , Endófitos/genética , Etanol/química , Etanol/farmacologia , Folhas de Planta/microbiologia , Plantas Medicinais/microbiologia , RNA Ribossômico/análise , Análise de Sequência de DNA/métodos , Tripanossomicidas/química
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