Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
2.
Plants (Basel) ; 12(18)2023 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-37765372

RESUMO

As agricultural practices become more sustainable, adopting more sustainable practices will become even more relevant. Searching for alternatives to chemical compounds has been the focus of numerous studies, and bacteriocins are tools with intrinsic biotechnological potential for controlling plant diseases. We continued to explore the biotechnological activity of the bacteriocin Gluconacin from Gluconacetobacter diazotrophicus, PAL5 strain, by investigating this protein's antagonism against important tomato phytopathogens and demonstrating its effectiveness in reducing bacterial spots caused by Xanthomonas perforans. In addition to this pathogen, the bacteriocin Gluconacin demonstrated bactericidal activity in vitro against Ralstonia solanacearum and Pseudomonas syringae pv. tomato, agents that cause bacterial wilt and bacterial spots, respectively. Bacterial spot control tests showed that Gluconacin reduced disease severity by more than 66%, highlighting the biotechnological value of this peptide in ecologically correct formulations.

3.
Int J Mol Sci ; 23(15)2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35955667

RESUMO

Gluconacetobacter diazotrophicus has been the focus of several studies aiming to understand the mechanisms behind this endophytic diazotrophic bacterium. The present study is the first global analysis of the early transcriptional response of exponentially growing G. diazotrophicus to iron, an essential cofactor for many enzymes involved in various metabolic pathways. RNA-seq, targeted gene mutagenesis and computational motif discovery tools were used to define the G. diazotrophicusfur regulon. The data analysis showed that genes encoding functions related to iron homeostasis were significantly upregulated in response to iron limitations. Certain genes involved in secondary metabolism were overexpressed under iron-limited conditions. In contrast, it was observed that the expression of genes involved in Fe-S cluster biosynthesis, flagellar biosynthesis and type IV secretion systems were downregulated in an iron-depleted culture medium. Our results support a model that controls transcription in G. diazotrophicus by fur function. The G. diazotrophicusfur protein was able to complement an E. colifur mutant. These results provide new insights into the effects of iron on the metabolism of G. diazotrophicus, as well as demonstrate the essentiality of this micronutrient for the main characteristics of plant growth promotion by G. diazotrophicus.


Assuntos
Gluconacetobacter , Ferro , Proteínas de Bactérias/metabolismo , Meios de Cultura/farmacologia , Ferro/metabolismo , Transcriptoma
4.
Braz J Microbiol ; 53(1): 281-288, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35060090

RESUMO

The production of 3-indoleacetic acid (IAA) by plant growth-promoting bacteria (PGPR) stimulates root development and plant growth. In addition, morphological changes such as an increased root ramification and root hair production improves nutrient absorption and biomass accumulation. The objective of this work was to evaluate the effect of IAA-producing strains on rice in an advanced stage of its vegetative cycle. Rice was inoculated with Gluconacetobacter diazotrophicus PAL 5 and its lao- mutant, deficient in auxin production, Azospirillum baldaniorum Sp 245, and Escherichia coli DH10b. Both the mutant and wild-type G. diazotrophicus stimulated root elongation, area, volume, and diameter. However, the lao- mutant strain was the only one capable of increasing the number of roots. In turn, inoculation with A. baldaniorum had no significant effect on plant development. The inoculation with E. coli led to changes in root volume, area, and diameter, and a response that may be related to the stress caused by its presence. We conclude that the inoculation with G. diazotrophicus stimulates the root system's growth independently of their IAA production ability, suggesting that a metabolite other than IAA is responsible for this effect at advanced stages of the rice's vegetative cycle.


Assuntos
Oryza , Escherichia coli/genética , Escherichia coli/metabolismo , Ácidos Indolacéticos/metabolismo , Oryza/microbiologia , Raízes de Plantas/microbiologia
5.
Life (Basel) ; 11(11)2021 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-34833106

RESUMO

The biosynthesis of exopolysaccharides (EPSs) is essential for endophytic bacterial colonisation in plants bacause this exopolymer both protects bacterial cells against the defence and oxidative systems of plants and acts on the plant colonisation mechanism in Gluconacetobacter diazotrophicus. The pathway involved in the biosynthesis of bacterial EPS has not been fully elucidated, and several areas related to its molecular regulation mechanisms are still lacking. G. diazotrophicus relies heavily on EPS for survival indirectly by protecting plants from pathogen attack as well as for endophytic maintenance and adhesion in plant tissues. Here, we report that EPS from G. diazotrophicus strain Pal5 is a signal polymer that controls its own biosynthesis. EPS production depends on a bacterial tyrosine (BY) kinase (Wzc) that consists of a component that is able to phosphorylate a glycosyltranferase or to self-phosphorylate. EPS interacts with the extracellular domain of Wzc, which regulates kinase activity. In G. diazotrophicus strains that are deficient in EPS production, the Wzc is rendered inoperative by self-phosphorylation. The presence of EPS promotes the phosphorylation of a glycosyltransferase in the pathway, thus producing EPS. Wzc-mediated self-regulation is an attribute for the control of exopolysaccharide biosynthesis in G. diazotrophicus.

6.
Curr Microbiol ; 78(8): 3079-3091, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34173016

RESUMO

The extracellular space in plants, termed the apoplast, has a pH and sugar content that enables bacterial growth and represents a possible niche for the establishment of endophytic bacteria. Previous studies have investigated the effects of diazotrophic bacteria inoculation in sugarcane varieties, but it has not yet been analyzed how the microbial community of apoplast fluid of sugarcane is affected. High-throughput next generation sequencing of the 16S rRNA gene was used throughout this study to determine the effect of inoculation with a diazotrophic bacteria consortium, previously isolated from sugarcane, on the native bacterial population of sugarcane variety RB867515 grown in the field. The analyses were carried out 450 days after inoculation. The results revealed the presence of 22 phyla, with predominance of Proteobacteria phylum. It was observed that the inoculated consortium changed the indigenous bacterial community structure of sugarcane apoplast fluid by decreasing diversity and evenness, interfering in the composition of rare species. Microbial community composition analysis revealed differences between treatments. The differential abundance test showed there were 43 amplicon sequence variants (ASVs) which were relatively more abundant in the inoculated treatment, with predominance of the Sphingomonas genus. The predicted functions of the most abundant ASVs revealed the presence of genera related to plant growth promotion and protection against phytopathogens. Analysis to evaluate the occurrence of inoculated strains in the recovered data was not conclusive since the ASVs taxonomically close to the inoculated bacteria were observed in low abundance. The present study is the first report to elucidate the bacterial community in sugarcane apoplast fluid using a culture-independent approach. It demonstrated that the diazotrophic bacterial consortium interferes in the natural bacterial community in sugarcane variety RB867515.


Assuntos
Microbiota , Saccharum , Bactérias/genética , Proteobactérias , RNA Ribossômico 16S/genética
7.
3 Biotech ; 11(6): 292, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34136329

RESUMO

Bacterial transcriptome profiling in the presence of plant fluids or extracts during microbial growth may provide relevant information on plant-bacteria interactions. Here, RNA sequencing (RNA-Seq) was used to determine the transcriptomic profile of Herbaspirillum seropedicae strain HRC54 at the early stages of response to sugarcane apoplastic fluid. Differentially expressed gene (DEG) analysis was performed using the DESeq2 and edgeR packages, followed by functional annotation using Blast2GO and gene ontology enrichment analysis using the COG and KEGG databases. After 2 h of sugarcane apoplastic fluid addition to the H. seropedicae HRC54 culture, respectively, 44 and 45 genes were upregulated and downregulated. These genes were enriched in bacterial metabolism (e.g., oxidoreductase and transferase), ABC transporters, motility, secretion systems, and signal transduction. RNA-Seq expression profiles of 12 genes identified in data analyses were verified by RT-qPCR. The results suggested that H. seropedicae HRC54 recognized sugarcane apoplastic fluid as the host signal, and some DEGs were closely involved at the early stages of the establishment of plant-bacteria interactions. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02848-y.

8.
Front Microbiol ; 12: 659965, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34054757

RESUMO

Bacteria of the genus Bacillus can colonize endophytically and benefit several crops including the control of some pest orders. In view of the benefits provided by these microorganisms and in order to find out an efficient biotechnological control for the giant borer, our interest in studying the microorganisms in symbiosis with sugarcane and the giant borer has arisen, since there is no efficient chemical or biological control method for this pest. Therefore, endophytic Bacillus strains were isolated from three sugarcane niches (apoplast fluid, central internode cylinder and roots) and also from the giant borer larvae living inside sugarcane varieties grown in the Northeast region of Brazil. The taxonomical characterization (16S rRNA) of 157 Gram-positive isolates showed that 138 strains belonged to the Bacillus genus. The most representative species were phylogenetically closely related to B. megaterium (11.5%) followed by B. safensis (10.8%), B. cereus (8.9%), B. oleronius (8.9%), B. amyloliquefaciens (7.0%), and B. pacificus (6.4%). BOX-PCR analyses showed very distinct band pattern profiles suggesting a great diversity of Bacillus species within the sugarcane niches and the digestive tract, while the B. cereus group remained very closely clustered in the dendrogram. According to XRE biomarker analysis, eleven strains (FORCN005, 007, 008, 011, 012, 014, 067, 076, 092, 093, and 135) correspond to B. thuringiensis species. Additional studies using conserved genes (glp, gmk, pta, and tpi) indicated that most of these strains were phylogenetically closely related to B. thuringiensis and may be considered different subspecies. In conclusion, this study suggests that the culturable Bacillus species are greatly diversified within the plant niches and showed Bacillus species in the digestive tract of the giant borer for the first time. These results open new perspectives to understand the role and functions played by these microorganisms in symbiosis with this pest and also the possibility of developing an efficient biological control method for the giant borer using strains identified as the B. thuringiensis species.

9.
Microbiol Res ; 244: 126651, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33383369

RESUMO

Gluconacetobacter diazotrophicus is a species of great agronomic potential due to its growth-promotion traits. Its colonization process in different plants has been reported. However, there have been no studies regarding its structural colonization in elephant grass. This is a fast-growing C4-Poaceae plant, and its application in Brazil is mainly aimed at feeding dairy cattle, due to its high nutritional value. Also, in the last decade, this grass has been applied in the production of biofuels. The present study aimed to monitor the colonization process of strain LP343 of G. diazotrophicus inoculated in elephant grass seedlings of PCEA genotype, by using a mCherry-tagged bacterium. Samples of roots and shoots collected at different periods were visualized by confocal laser-scanning microscopy. The colony-counting assay was used to compare the number of cells recovered in different niches and a qPCR was performed for the quantification of endophytic cells in root and shoot tissues. Results suggested that the strain LP343 quickly recognized the PCEA roots as host, attached to the elephant grass roots at 6 h, and 7 days after inoculation were able to colonize the xylem vessels of roots and shoots of elephant grass. This study advances our knowledge about the colonization process of G. diazotrophicus species in elephant grass, contributing to future studies involving the plant-bacteria interaction cultivated under gnotobiotic conditions.


Assuntos
Gluconacetobacter/crescimento & desenvolvimento , Pennisetum/microbiologia , Raízes de Plantas/microbiologia , Brotos de Planta/microbiologia , Brasil , Vida Livre de Germes , Gluconacetobacter/genética , Gluconacetobacter/isolamento & purificação , Pennisetum/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Brotos de Planta/crescimento & desenvolvimento , Plântula/crescimento & desenvolvimento , Plântula/microbiologia
10.
Int J Mol Sci ; 21(1)2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31947822

RESUMO

BACKGROUND: Inoculation with Gluconacetobacter diazotrophicus has shown to influence root development in red rice plants, and more recently, the induced systemic tolerance (IST) response to drought was also demonstrated. The goal of this study was to evaluate the inoculation effect of G. diazotrophicus strain Pal5 on the amelioration of drought stress and root development in red rice (Oryza sativa L.). METHODS: The experimental treatments consist of red rice plants inoculated with and without strain Pal5 in presence and absence of water restriction. Physiological, biochemical, and molecular analyses of plant roots were carried out, along with measurements of growth and biochemical components. RESULTS: The plants showed a positive response to the bacterial inoculation, with root growth promotion and induction of tolerance to drought. An increase in the root area and higher levels of osmoprotectant solutes were observed in roots. Bacterial inoculation increased the drought tolerance and positively regulated certain root development genes against the water deficit in plants. CONCLUSION: G. diazotrophicus Pal5 strain inoculation favored red rice plants by promoting various root growth and developmental mechanisms against drought stress, enabling root development and improving biochemical composition.


Assuntos
Gluconacetobacter/fisiologia , Oryza/microbiologia , Raízes de Plantas/microbiologia , Secas , Oryza/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Estresse Fisiológico , Simbiose , Água/metabolismo
11.
AIDS Behav ; 23(Suppl 3): 287-295, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31520241

RESUMO

Test and Rapid Response Treatment (TRRT) linkage programs have demonstrated improved HIV suppression rates. This paper describes the design and implementation of the Miami TRRT initiative and its clinical impact. Assisted by a dedicated care navigator, patients receiving a reactive HIV rapid test at the Florida Department of Health STD Clinic were offered same-day HIV care at the University of Miami/Jackson Memorial Medical Center Adult HIV Outpatient Clinic. Patient retention and labs were tracked for 12 months. Of the 2337 individuals tested, 46 had a reactive HIV test; 41 (89%) consented to participate. For the 36 patients in continued care for a year, 33 (91.7%) achieved virological suppression (< 200 copies/mL) within 70 days of their reactive HIV rapid test; at 12 months, 35 (97.2%) remained suppressed, and mean CD4 T cell counts increased from 452 ± 266 to 597 ± 322 cells/mm3. The Miami TRRT initiative demonstrated that immediate linkage to care is feasible and improves retention and suppression in a public/academic medical center in the U.S. South.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/diagnóstico , Infecções por HIV/tratamento farmacológico , Programas de Rastreamento/métodos , Navegação de Pacientes , Cooperação e Adesão ao Tratamento/psicologia , Centros Médicos Acadêmicos , Adulto , Instituições de Assistência Ambulatorial , Contagem de Linfócito CD4 , Continuidade da Assistência ao Paciente , Feminino , Florida , Infecções por HIV/virologia , Humanos , Masculino , Avaliação de Programas e Projetos de Saúde , Resultado do Tratamento , Carga Viral
12.
Braz J Microbiol ; 50(3): 777-789, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31177380

RESUMO

Nine bacterial strains were previously isolated in association with pinewood nematode (PWN) from wilted pine trees. They proved to be nematicidal in vitro, and one of the highest activities, with potential to control PWN, was showed by Serratia sp. M24T3. Its ecology in association with plants remains unclear. This study aimed to evaluate the ability of strain M24T3 to colonize the internal tissues of the model plant Arabidopsis thaliana using confocal microscopy. Plant growth-promoting bacteria (PGPB) functional traits were tested and retrieved in the genome of strain M24T3. In greenhouse conditions, the bacterial effects of all nematicidal strains were also evaluated, co-inoculated or not with Bradyrhizobium sp. 3267, on Vigna unguiculata fitness. Inoculation of strain M24T3 increased the number of A. thaliana lateral roots and the confocal analysis confirmed effective bacterial colonization in the plant. Strain M24T3 showed cellulolytic activity, siderophores production, phosphate and zinc solubilization ability, and indole acetic acid production independent of supplementation with L-tryptophan. In the genome of strain M24T3, genes involved in the interaction with the plants such as 1-aminocyclopropane-1-carboxylate (ACC) deaminase, chitinolytic activity, and quorum sensing were also detected. The genomic organization showed ACC deaminase and its leucine-responsive transcriptional regulator, and the activity of ACC deaminase was 594.6 nmol α-ketobutyrate µg protein-1 µl-1. Strain M24T3 in co-inoculation with Bradyrhizobium sp. 3267 promoted the growth of V. unguiculata. In conclusion, this study demonstrated the ability of strain M24T3 to colonize other plants besides pine trees as an endophyte and displays PGPB traits that probably increased plant tolerance to stresses.


Assuntos
Arabidopsis/microbiologia , Nematoides/microbiologia , Serratia/fisiologia , Animais , Antibiose , Arabidopsis/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Carbono-Carbono Liases/genética , Carbono-Carbono Liases/metabolismo , Pinus/parasitologia , Doenças das Plantas/parasitologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Percepção de Quorum , Serratia/enzimologia , Serratia/genética , Serratia/isolamento & purificação , Vigna/crescimento & desenvolvimento , Vigna/microbiologia
13.
PLoS One ; 13(12): e0207863, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30550601

RESUMO

The stalk apoplast fluid of sugarcane contains different sugars, organic acids and amino acids that may supply the demand for carbohydrates by endophytic bacteria including diazotrophs P. tropica (syn. B. tropica) strain Ppe8, isolated from sugarcane, is part of the bacterial consortium recommended as inoculant to sugarcane. However, little information has been accumulated regarding this plant-bacterium interaction considering that it colonizes internal sugarcane tissues. Here, we made use of the RNA-Seq transcriptomic analysis to study the influence of sugarcane stalk apoplast fluid on Ppe8 gene expression. The bacterium was grown in JMV liquid medium (100 ml), divided equally and then supplemented with 50 ml of fresh JMV medium or 50 ml of apoplast fluid extracted from sugarcane variety RB867515. Total RNA was extracted 2 hours later, the rRNAs were depleted and mRNAs used to construct libraries to sequence the fragments using Ion Torrent technology. The mapping and statistical analysis were carried out with CLC Genomics Workbench software. The RNA-seq data was validated by RT-qPCR using the reference genes fliP1, paaF, and groL. The data analysis showed that 544 genes were repressed and 153 genes were induced in the presence of apoplast fluid. Genes that induce plant defense responses, genes related to chemotaxis and movements were repressed in the presence of apoplast fluid, indicating that strain Ppe8 recognizes the apoplast fluid as a plant component. The expression of genes involved in bacterial metabolism was regulated (up and down), suggesting that the metabolism of strain Ppe8 is modulated by the apoplast fluid. These results suggest that Ppe8 alters its gene expression pattern in the presence of apoplast fluid mainly in order to use compounds present in the fluid as well as to avoid the induction of plant defense mechanisms. This is a pioneer study showing the role played by the sugarcane apoplast fluid on the global modulation of genes in P. tropica strain Ppe8.


Assuntos
Burkholderiaceae/genética , Burkholderiaceae/metabolismo , Endófitos/genética , Endófitos/metabolismo , Saccharum/metabolismo , Saccharum/microbiologia , Aminoácidos/metabolismo , Transporte Biológico Ativo , Metabolismo dos Carboidratos , Movimento Celular/genética , Parede Celular/genética , Quimiotaxia/genética , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Estruturas Vegetais/metabolismo , Estruturas Vegetais/microbiologia , Transdução de Sinais
14.
Braz. j. microbiol ; 49(2): 210-211, Apr.-June 2018.
Artigo em Inglês | LILACS | ID: biblio-889231

RESUMO

Abstract Paraburkholderia tropica (syn Burkholderia tropica) are nitrogen-fixing bacteria commonly found in sugarcane. The Paraburkholderia tropica strain Ppe8 is part of the sugarcane inoculant consortium that has a beneficial effect on yield. Here, we report a draft genome sequence of this strain elucidating the mechanisms involved in its interaction mainly with Poaceae. A genome size of approximately 8.75 Mb containing 7844 protein coding genes distributed in 526 subsystems was de novo assembled with ABySS and annotated by RAST. Genes related to the nitrogen fixation process, the secretion systems (I, II, III, IV, and VI), and related to a variety of metabolic traits, such as metabolism of carbohydrates, amino acids, vitamins, and proteins, were detected, suggesting a broad metabolic capacity and possible adaptation to plant association.


Assuntos
Genoma Bacteriano , Burkholderiaceae/genética , Endófitos/genética , Proteínas de Bactérias/genética , Análise de Sequência de DNA , Biologia Computacional , Saccharum/microbiologia , Burkholderiaceae/isolamento & purificação , Redes e Vias Metabólicas/genética , Anotação de Sequência Molecular , Endófitos/isolamento & purificação
15.
Braz J Microbiol ; 49(2): 210-211, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29122479

RESUMO

Paraburkholderia tropica (syn Burkholderia tropica) are nitrogen-fixing bacteria commonly found in sugarcane. The Paraburkholderia tropica strain Ppe8 is part of the sugarcane inoculant consortium that has a beneficial effect on yield. Here, we report a draft genome sequence of this strain elucidating the mechanisms involved in its interaction mainly with Poaceae. A genome size of approximately 8.75Mb containing 7844 protein coding genes distributed in 526 subsystems was de novo assembled with ABySS and annotated by RAST. Genes related to the nitrogen fixation process, the secretion systems (I, II, III, IV, and VI), and related to a variety of metabolic traits, such as metabolism of carbohydrates, amino acids, vitamins, and proteins, were detected, suggesting a broad metabolic capacity and possible adaptation to plant association.


Assuntos
Burkholderiaceae/genética , Endófitos/genética , Genoma Bacteriano , Proteínas de Bactérias/genética , Burkholderiaceae/isolamento & purificação , Biologia Computacional , Endófitos/isolamento & purificação , Redes e Vias Metabólicas/genética , Anotação de Sequência Molecular , Saccharum/microbiologia , Análise de Sequência de DNA
16.
Antonie Van Leeuwenhoek ; 110(12): 1555-1568, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28695409

RESUMO

Quantitative reverse transcription PCR (RT-qPCR) is an important tool for evaluating gene expression. However, this technique requires that specific internal normalizing genes be identified for different experimental conditions. To date, no internal normalizing genes are available for validation of data analyses for Herbaspirillum rubrisubalbicans strain HCC103, an endophyte that is part of the sugarcane consortium inoculant. This work seeks to identify and evaluate suitable reference genes for gene expression studies in HCC103 grown until middle log phase in sugarcane juice obtained from four sugarcane varieties or media with three different carbon sources. The mRNA levels of five candidate genes (rpoA, gyrA, dnaG, recA and gmK) and seven target genes involved in carbon metabolism (acnA, fbp, galE, suhB, wcaA, ORF_0127.0101 and _0127.0123) were quantified by RT-qPCR. Analysis of expression stability of these genes was carried out using geNorm and Normfinder software. The results indicated that the HCC103 dnaG and gyrA genes are the most stable and showed adequate relative expression level changes among the different sugarcane juices. The highest expression level was seen for ORF_0127.0101, which encodes a sugar transporter, in juice from sugarcane variety RB867515 and glucose as the carbon source. The suhB gene, encoding SuhB inositol monophosphatase, had a higher relative expression level on 0.5% glucose, 100% sugarcane juice from variety RB867515 and 0.5% aconitate. Together the results suggest that dnaG and gyrA genes are suitable as reference genes for RT-qPCR analysis of strain HCC103 and that juice from different sugarcane varieties modulates the expression of key genes involved in carbon metabolism.


Assuntos
Carbono/metabolismo , Sucos de Frutas e Vegetais , Genes Bacterianos , Herbaspirillum/efeitos dos fármacos , Herbaspirillum/fisiologia , Saccharum/química , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Estabilidade de RNA , Reação em Cadeia da Polimerase em Tempo Real , Transcriptoma
17.
Front Microbiol ; 7: 1572, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27774087

RESUMO

Gluconacetobacter diazotrophicus is a beneficial nitrogen-fixing endophyte found in association with sugarcane plants and other important crops. Beneficial effects of G. diazotrophicus on sugarcane growth and productivity have been attributed to biological nitrogen fixation process and production of phytohormones especially indole-3-acetic acid (IAA); however, information about the biosynthesis and function of IAA in G. diazotrophicus is still scarce. Therefore, the aim of this work was to identify genes and pathways involved in IAA biosynthesis in this bacterium. In our study, the screening of two independent Tn5 mutant libraries of PAL5T strain using the Salkowski colorimetric assay revealed two mutants (Gdiaa34 and Gdiaa01), which exhibited 95% less indolic compounds than the parental strain when grown in LGIP medium supplemented with L-tryptophan. HPLC chromatograms of the wild-type strain revealed the presence of IAA and of the biosynthetic intermediates indole-3-pyruvic acid (IPyA) and indole-3-lactate (ILA). In contrast, the HPLC profiles of both mutants showed no IAA but only a large peak of non-metabolized tryptophan and low levels of IPyA and ILA were detected. Molecular characterization revealed that Gdiaa01 and Gdiaa34 mutants had unique Tn5 insertions at different sites within the GDI2456 open read frame, which is predicted to encode a L-amino acid oxidase (LAAO). GDI2456 (lao gene) forms a cluster with GDI2455 and GDI2454 ORFs, which are predicted to encode a cytochrome C and an RidA protein, respectively. RT-qPCR showed that transcript levels of lao. cccA, and ridA genes were reduced in the Gdiaa01 as compared to PAL5T. In addition, rice plants inoculated with Gdiaa01 showed significantly smaller root development (length, surface area, number of forks and tips) than those plants inoculated with PAL5T. In conclusion, our study demonstrated that G. diazotrophicus PAL5T produces IAA via the IPyA pathway in cultures supplemented with tryptophan and provides evidence for the involvement of an L-amino acid oxidase gene cluster in the biosynthesis of IAA. Furthermore, we showed that the mutant strains with reduction in IAA biosynthesis ability, in consequence of the lower transcription levels of genes of the lao cluster, had remarkable effects on development of rice roots.

18.
Antonie Van Leeuwenhoek ; 109(11): 1493-1502, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27535840

RESUMO

Among the members of the genus Burkholderia, Burkholderia tropica has the ability to fix nitrogen and promote sugarcane plant growth as well as act as a biological control agent. There is little information about how this bacterium metabolizes carbohydrates as well as those carbon sources found in the sugarcane juice that accumulates in stems during plant growth. Reverse transcription quantitative PCR (RT-qPCR) can be used to evaluate changes in gene expression during bacterial growth on different carbon sources. Here we tested the expression of six reference genes, lpxC, gyrB, recA, rpoA, rpoB, and rpoD, when cells were grown with glucose, fructose, sucrose, mannitol, aconitic acid, and sugarcane juice as carbon sources. The lpxC, gyrB, and recA were selected as the most stable reference genes based on geNorm and NormFinder software analyses. Validation of these three reference genes during strain Ppe8 growth on the same carbon sources showed that genes involved in glycogen biosynthesis (glgA, glgB, glgC) and trehalose biosynthesis (treY and treZ) were highly expressed when Ppe8 was grown in aconitic acid relative to other carbon sources, while otsA expression (trehalose biosynthesis) was reduced with all carbon sources. In addition, the expression level of the ORF_6066 (gluconolactonase) gene was reduced on sugarcane juice. The results confirmed the stability of the three selected reference genes (lpxC, gyrB, and recA) during the RT-qPCR and also their robustness by evaluating the relative expression of genes involved in glycogen and trehalose biosynthesis when strain Ppe8 was grown on different carbon sources and sugarcane juice.


Assuntos
Burkholderia/genética , Perfilação da Expressão Gênica , Genes Bacterianos , Saccharum/microbiologia , Carbono/metabolismo , Reação em Cadeia da Polimerase em Tempo Real/métodos
19.
J Microbiol Methods ; 127: 193-196, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27302038

RESUMO

The RT-qPCR technique needs a validated set of reference genes for ensuring the consistency of the results from the gene expression. Expression stabilities for 9 genes from Herbaspirillum seropedicae, strain HRC54, grown with different carbon sources were calculated using geNorm and NormFinder, and the gene rpoA showed the best stability values.


Assuntos
Genes Bacterianos , Genes Essenciais , Herbaspirillum/genética , Reação em Cadeia da Polimerase em Tempo Real/métodos , Carbono/metabolismo , Herbaspirillum/metabolismo
20.
Rev. ABENO ; 16(1): 125-137, 2016. tab, graf
Artigo em Português | BBO - Odontologia | ID: biblio-881583

RESUMO

Considerando a educação humanística como uma condição necessária para formação política em odontologia, objetivou-se identificar a percepção de estudantes acerca da política nos conteúdos de saúde bucal coletiva e se é possível, assim, realizar uma educação política desses estudantes. Uma intervenção pedagógica do tipo investigaçãoação foi realizada cujo cenário foi a disciplina 'Saúde coletiva II' no Curso de Odontologia do Campus Arcoverde da Universidade de Pernambuco. Dezessete estudantes do 2º período participaram elaborando resenhas sobre suas percepções sobre política a partir do conteúdo estudado. Usou-se o método de Análise de Conteúdo de Bardin a partir das resenhas para definir se, o que foi identificado como 'política', se aproximava de um letramento político. Totalizou-se 185 ideias sobre política que foram agrupadas em oito categorias: 'Trânsito da Odontologia entre a perspectiva integral e a perspectiva técnica', 'Informação como requisito essencial', 'As políticas públicas de saúde (operacionalização via Estado)', 'Participação dos envolvidos nas decisões', 'Planejamento das ações de saúde', 'A formação do cirurgião-dentista', 'O saber da Saúde Bucal Coletiva' e 'Portarias ministeriais'. 70,3% dessas ideias parecem servir para um letramento político. Conclui-se que parece haver um caminho pedagógico que pode ser percorrido para se obter um letramento político dos estudantes de odontologia investigados (AU).


Considering humanistic education as a necessary condition for political formation in dentistry, this study aimed to identify students perceptions about politics in contents of the discipline of community oral health and if it is possible, through these contents, to build a political education of these students. For this, a research-action type educational intervention was conducted where the pedagogical scenario was the curricular discipline 'Public health II' of the Dental Course of Universidade de Pernambuco (UPE), Campus Arcoverde. Seventeen students of the 2nd Semester participated in the research making reviews about their perceptions about politics from the content studied in the discipline. A content analysis method according Bardin was used to set up whether the content identified as 'politics' approached a political literacy. A total of 185 views about politics which were grouped into eight categories: 'Movement of Dentistry between full perspective and technical perspective', 'Information as an essential requirement', 'Public health policies (implementation via State)', 'Stakeholder involvement in decision-making',' Planning of health practices', 'The formation of the dentist', 'Knowledge of Public Oral health' and 'Ministerial Decrees'. 70.3% of these ideas seem to serve as a political literacy. In conclusion, there seems to be an educational path that can be followed to obtain a political literacy of dental students investigated (AU).


Assuntos
Humanos , Estudantes de Odontologia , Sistema Único de Saúde , Educação em Odontologia , Percepção Social , Pesquisa Qualitativa
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...