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1.
J Microbiol ; 57(6): 450-460, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31012060

RESUMO

Next-generation DNA sequencing technology was applied to generate molecular data from semiarid reservoirs during well-defined seasons. Target sequences of 16S-23S rRNA ITS and cpcBA-IGS were used to reveal the taxonomic groups of cyanobacteria present in the samples, and genes coding for cyanotoxins such as microcystins (mcyE), saxitoxins (sxtA), and cylindrospermopsins (cyrJ) were investigated. The presence of saxitoxins in the environmental samples was evaluated using ELISA kit. Taxonomic analyses of high-throughput DNA sequencing data showed the dominance of the genus Microcystis in Mundaú reservoir. Furthermore, it was the most abundant genus in the dry season in Ingazeira reservoir. In the rainy season, 16S-23S rRNA ITS analysis revealed that Cylindrospermopsis raciborskii comprised 46.8% of the cyanobacterial community in Ingazeira reservoir, while the cpcBAIGS region revealed that C. raciborskii (31.8%) was the most abundant taxon followed by Sphaerospermopsis aphanizomenoides (17.3%) and Planktothrix zahidii (16.6%). Despite the presence of other potential toxin-producing genera, the detected sxtA gene belonged to C. raciborskii, while the mcyE gene belonged to Microcystis in both reservoirs. The detected mcyE gene had good correlation with MC content, while the amplification of the sxtA gene was related to the presence of STX. The cyrJ gene was not detected in these samples. Using DNA analyses, our results showed that the cyanobacterial composition of Mundaú reservoir was similar in successive dry seasons, and it varied between seasons in Ingazeira reservoir. In addition, our data suggest that some biases of analysis influenced the cyanobacterial communities seen in the NGS output of Ingazeira reservoir.


Assuntos
Biodiversidade , Cianobactérias/classificação , Cianobactérias/isolamento & purificação , Água Potável/microbiologia , Análise de Sequência de DNA/métodos , Microbiologia da Água , Abastecimento de Água , Toxinas Bacterianas/análise , Toxinas Bacterianas/genética , Toxinas Bacterianas/isolamento & purificação , Brasil , Cianobactérias/genética , DNA Bacteriano/análise , Monitoramento Ambiental/métodos , Genes Bacterianos/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Metagenômica/métodos , Microcystis/genética , RNA Ribossômico 16S/genética , RNA Ribossômico 23S/genética , Saxitoxina/genética , Estações do Ano , Uracila/análogos & derivados
2.
Biotechnol Lett ; 40(9-10): 1395-1406, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30062528

RESUMO

OBJECTIVE: To isolate putative lipase enzymes by screening a Cerrado soil metagenomic library with novel features. RESULTS: Of 6720 clones evaluated, Clone W (10,000 bp) presented lipolytic activity and four predicted coding sequences, one of them LipW. Characterization of a predicted esterase/lipase, LipW, showed 28% sequence identity with an arylesterase from Pseudomonas fluorescens (pdb|3HEA) from protein database (PDB). Phylogenetic analysis showed LipW clustered with family V lipases; however, LipW was clustered in different subclade belonged to family V, suggesting a different subgroup of family V. In addition, LipW presented a difference in family V GH motif, a glycine replaced by a serine in GH motif. Estimated molecular weight and stokes radius values of LipW were 29,338.67-29,411.98 Da and 2.58-2.83 nm, respectively. Optimal enzyme activity was observed at pH 9.0-9.5 and at 40 °C. Circular dichroism analysis estimated secondary structures percentages as approximately 45% α-helix and 15% ß-sheet, consistent with the 3D structure predicted by homology. CONCLUSION: Our results demonstrate the isolation of novel family V lipolytic enzyme with biotechnological applications from a metagenomic library.


Assuntos
Esterases/genética , Esterases/metabolismo , Microbiologia do Solo , Motivos de Aminoácidos , Brasil , Dicroísmo Circular , Clonagem Molecular , Esterases/química , Metagenoma , Modelos Moleculares , Peso Molecular , Filogenia , Conformação Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Espectrometria de Fluorescência
3.
Plant Dis ; 102(4): 773-781, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30673401

RESUMO

Eighty-one Rhizoctonia-like isolates were identified based on morphology and nuclei-staining methods from natural and agricultural soils of the Cerrado (Brazilian savanna). The nucleotide similarity analysis of ITS1-5.8S-ITS2 regions identified 14 different taxa, with 39.5% of isolates assigned to Waitea circinata (zeae, oryzae, and circinata varieties), while 37.0% belonged to Thanatephorus cucumeris anastomosis groups (AGs) AG1-IB, AG1-ID, AG1-IE, AG4-HGI, and AG4-HGIII. Ceratobasidium spp. AG-A, AG-F, AG-Fa, AG-P, and AG-R comprised 23.5%. Rhizoctonia zeae (19.8%), R. solani AG1-IE (18.6%), and binucleate Rhizoctonia AG-A (8.6%) were the most frequent anamorphic states found. Root rot severity caused by the different taxa varied from low to high on common beans, and tended to be low to average in maize. Twenty-two isolates were pathogenic to both hosts, suggesting difficulties in managing Rhizoctonia root rots with crop rotation. These results suggest that cropping history affects the geographical arrangement of AGs, with a prevalence of AG1 in the tropical zone from central to north Brazil while the AG4 group was most prevalent from central to subtropical south. W. circinata var. zeae was predominant in soils under maize production. To our knowledge, this is the first report on the occurrence of W. circinata var. circinata in Brazil.


Assuntos
Produtos Agrícolas/microbiologia , Doenças das Plantas/microbiologia , Rhizoctonia/genética , Rhizoctonia/patogenicidade , Brasil , Filogenia
4.
Microb Ecol ; 74(1): 89-105, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28070679

RESUMO

Semi-arid and arid areas occupy about 33% of terrestrial ecosystems. However, little information is available about microbial diversity in the semi-arid Caatinga, which represents a unique biome that extends to about 11% of the Brazilian territory and is home to extraordinary diversity and high endemism level of species. In this study, we characterized the diversity of microbial genes associated with biomass conversion (carbohydrate-active enzymes, or so-called CAZYmes) in soil and freshwater of the Caatinga. Our results showed distinct CAZYme profiles in the soil and freshwater samples. Glycoside hydrolases and glycosyltransferases were the most abundant CAZYme families, with glycoside hydrolases more dominant in soil (∼44%) and glycosyltransferases more abundant in freshwater (∼50%). The abundances of individual glycoside hydrolase, glycosyltransferase, and carbohydrate-binding module subfamilies varied widely between soil and water samples. A predominance of glycoside hydrolases was observed in soil, and a higher contribution of enzymes involved in carbohydrate biosynthesis was observed in freshwater. The main taxa associated with the CAZYme sequences were Planctomycetia (relative abundance in soil, 29%) and Alphaproteobacteria (relative abundance in freshwater, 27%). Approximately 5-7% of CAZYme sequences showed low similarity with sequences deposited in non-redundant databases, suggesting putative homologues. Our findings represent a first attempt to describe specific microbial CAZYme profiles for environmental samples. Characterizing these enzyme groups associated with the conversion of carbohydrates in nature will improve our understanding of the significant roles of enzymes in the carbon cycle. We identified a CAZYme signature that can be used to discriminate between soil and freshwater samples, and this signature may be related to the microbial species adapted to the habitat. The data show the potential ecological roles of the CAZYme repertoire and associated biotechnological applications.


Assuntos
Enzimas/análise , Água Doce/química , Solo/química , Alphaproteobacteria/enzimologia , Brasil , Carboidratos , Glicosídeo Hidrolases/análise , Glicosiltransferases/análise , Planctomycetales/enzimologia , Microbiologia do Solo , Microbiologia da Água
5.
Genome Announc ; 4(3)2016 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-27151783

RESUMO

Cylindrospermopsis raciborskii ITEP-A1 is a saxitoxin-producing cyanobacterium. We report the draft genome sequence of ITEP-A1, which comprised 195 contigs that were assembled with SPAdes and annotated with Rapid Annotation using Subsystem Technology. The identified genome sequence had 3,605,836 bp, 40.1% G+C, and predicted 3,553 coding sequences (including the synthetase genes).

6.
PLoS One ; 11(2): e0148296, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26881432

RESUMO

The Caatinga is a semi-arid biome in northeast Brazil. The Paraguaçú River is located in the Caatinga biome, and part of its course is protected by the National Park of Chapada Diamantina (PNCD). In this study we evaluated the effect of PNCD protection on the water quality and microbial community diversity of this river by analyzing water samples obtained from points located inside and outside the PNCD in both wet and dry seasons. Results of water quality analysis showed higher levels of silicate, ammonia, particulate organic carbon, and nitrite in samples from the unprotected area compared with those from protected areas. Pyrosequencing of the 16S rRNA genes revealed that Burkholderiales was abundant in samples from all three sites during both seasons and was represented primarily by the genus Polynucleobacter and members of the Comamonadaceae family (e.g., genus Limnohabitans). During the dry season, the unprotected area showed a higher abundance of Flavobacterium sp. and Arthrobacter sp., which are frequently associated with the presence and/or degradation of arsenic and pesticide compounds. In addition, genes that appear to be related to agricultural impacts on the environment, as well as those involved in arsenic and cadmium resistance, copper homeostasis, and propanediol utilization, were detected in the unprotected areas by metagenomic sequencing. Although PNCD protection improves water quality, agricultural activities around the park may affect water quality within the park and may account for the presence of bacteria capable of pesticide degradation and assimilation, evidencing possible anthropogenic impacts on the Caatinga.


Assuntos
Arthrobacter/classificação , Burkholderiaceae/classificação , Comamonadaceae/classificação , Flavobacterium/classificação , RNA Ribossômico 16S/genética , Rios/microbiologia , Qualidade da Água , Agricultura , Amônia/análise , Arthrobacter/genética , Brasil , Burkholderiaceae/genética , Carbono/análise , Comamonadaceae/genética , Ecossistema , Flavobacterium/genética , Sequenciamento de Nucleotídeos em Larga Escala , Metagenoma , Consórcios Microbianos/fisiologia , Nitritos/análise , Material Particulado/análise , Filogenia , Rios/química , Estações do Ano , Silicatos/análise
7.
Microb Ecol ; 70(2): 545-56, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25749937

RESUMO

The gut microbiota of termites allows them to thrive on a variety of different materials such as wood, litter, and soil. For that reason, they play important roles in the decomposition of biomass in diverse biomes. This function is essential in the savanna, where litter-feeding termites are one of the few invertebrates active during the dry season. In this study, we describe the gut microbiota of workers (third and fourth instars) of the species Syntermes wheeleri, a litter-feeding termite from the Brazilian savanna. Results of 16S and 18S ribosomal RNA (rRNA) gene-targeted pyrosequencing using primers sets specific to each domain have revealed its bacterial, archaeal, and fungal diversities. Firmicutes accounted for more than half of the operational taxonomic units of the Bacteria domain. The most abundant fungal species were from the class Dothideomycetes of the phylum Ascomycota. The methanogenic orders Methanobacteriales, Methanosarcinales, and Methanomicrobiales of the phylum Euryarchaeota accounted for the greatest part of the Archaea detected in this termite. A comparison of the gut microbiota of the two instars revealed a difference in operational taxonomic unit (OTU) abundance but not in species richness. This description of the whole gut microbiota represents the first study to evaluate relationships among bacteria, archaea, fungi, and host in S. wheeleri.


Assuntos
Isópteros/microbiologia , Animais , Archaea/classificação , Archaea/genética , Bactérias/classificação , Bactérias/genética , Fungos/classificação , Fungos/genética , Microbioma Gastrointestinal
8.
Biotechnol Lett ; 35(9): 1461-8, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23690037

RESUMO

Trichoderma spp. are used for biocontrol of several plant pathogens. However, their efficient interaction with the host needs to be accompanied by production of secondary metabolites and cell wall-degrading enzymes. Three parameters were evaluated after interaction between four Trichoderma species and plant-pathogenic fungi: Fusarium solani, Rhizoctonia solani and Sclerotinia sclerotiorum. Trichoderma harzianum and T. asperellum were the most effective antagonists against the pathogens. Most of the Trichoderma species produced toxic volatile metabolites, having significant effects on growth and development of the plant pathogens. When these species were grown in liquid cultures with cell walls from these plant pathogens, they produced and secreted ß-1,3-glucanase, NAGAse, chitinase, acid phosphatase, acid proteases and alginate lyase.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Fusarium/crescimento & desenvolvimento , Interações Microbianas , Rhizoctonia/crescimento & desenvolvimento , Trichoderma/enzimologia , Trichoderma/fisiologia , Antibiose , Antifúngicos/metabolismo , Ascomicetos/efeitos dos fármacos , Enzimas/metabolismo , Fusarium/efeitos dos fármacos , Controle Biológico de Vetores/métodos , Rhizoctonia/efeitos dos fármacos , Compostos Orgânicos Voláteis/metabolismo
9.
Fungal Biol ; 116(7): 815-24, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22749168

RESUMO

Some species of Trichoderma have successfully been used in the commercial biological control of fungal pathogens, e.g., Sclerotinia sclerotiorum, an economically important pathogen of common beans (Phaseolus vulgaris L.). The objectives of the present study were (1) to provide molecular characterization of Trichoderma strains isolated from the Brazilian Cerrado; (2) to assess the metabolic profile of each strain by means of Biolog FF Microplates; and (3) to evaluate the ability of each strain to antagonize S. sclerotiorum via the production of cell wall-degrading enzymes (CWDEs), volatile antibiotics, and dual-culture tests. Among 21 isolates, we identified 42.86% as Trichoderma asperellum, 33.33% as Trichoderma harzianum, 14.29% as Trichoderma tomentosum, 4.76% as Trichoderma koningiopsis, and 4.76% as Trichoderma erinaceum. Trichoderma asperellum showed the highest CWDE activity. However, no species secreted a specific group of CWDEs. Trichoderma asperellum 364/01, T. asperellum 483/02, and T. asperellum 356/02 exhibited high and medium specific activities for key enzymes in the mycoparasitic process, but a low capacity for antagonism. We observed no significant correlation between CWDE and antagonism, or between metabolic profile and antagonism. The diversity of Trichoderma species, and in particular of T. harzianum, was clearly reflected in their metabolic profiles. Our findings indicate that the selection of Trichoderma candidates for biological control should be based primarily on the environmental fitness of competitive isolates and the target pathogen.


Assuntos
Antibiose , Ascomicetos/crescimento & desenvolvimento , Biodiversidade , Phaseolus/microbiologia , Trichoderma/crescimento & desenvolvimento , Trichoderma/metabolismo , Brasil , DNA Fúngico/química , DNA Fúngico/genética , Metaboloma , Dados de Sequência Molecular , Análise de Sequência de DNA , Trichoderma/classificação , Trichoderma/genética
10.
J Microbiol Methods ; 81(1): 6-10, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20096308

RESUMO

Beta-1,3-glucanase is an important cell wall-degrading enzyme involved in mycoparasitism by Trichoderma spp. during antagonism against phytopathogenic fungi. A simple microplate-based method to assay beta-1,3-glucanase activity is described here as an alternative to an expensive tube-assay method. The reaction volume of the micro-assay was reduced to 130 microl from the 1150 microl used in the standard beta-1,3-glucanase macro-assay. Statistical analyses showed significant difference in sensitivity between the micro- and the macro-assay. The micro-method was optimized using the Response Surface Quadratic Model. The sensitivity of the optimized micro-method was shown to be four-fold greater than the macro-assay and two-fold higher than the micro-assay. The optimized micro-assay was significantly more sensitive in all of the twenty examined isolates during Trichoderma spp. beta-1,3-glucanase screening. We conclude that this modified and optimized method is more convenient, faster, cheaper and more reproducible than the traditional tube-assay.


Assuntos
Técnicas de Laboratório Clínico/métodos , Glucana 1,3-beta-Glucosidase/metabolismo , Programas de Rastreamento/métodos , Micologia/métodos , Trichoderma/enzimologia , Trichoderma/isolamento & purificação , Animais , Sensibilidade e Especificidade
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