Laboratorio Of Genetica Of Microrganismos

Rio de Janeiro, Brazil

Laboratorio Of Genetica Of Microrganismos

Rio de Janeiro, Brazil

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Rosada L.J.,Laboratorio Of Genetica Of Microrganismos | Sant'Anna J.R.,Laboratorio Of Genetica Of Microrganismos | Franco C.C.S.,Laboratorio Of Genetica Of Microrganismos | Esquissato G.N.M.,Laboratorio Of Genetica Of Microrganismos | And 6 more authors.
Journal of Food Protection | Year: 2013

Aspergillus flavus, a haploid organism found worldwide in a variety of crops, including maize, cottonseed, almond, pistachio, and peanut, causes substantial and recurrent worldwide economic liabilities. This filamentous fungus produces aflatoxins (AFLs) B1 and B2, which are among the most carcinogenic compounds from nature, acutely hepatotoxic and immunosuppressive. Recent efforts to reduce AFL contamination in crops have focused on the use of nonaflatoxigenic A. flavus strains as biological control agents. Such agents are applied to soil to competitively exclude native AFL strains from crops and thereby reduce AFL contamination. Because the possibility of genetic recombination in A. flavus could influence the stability of biocontrol strains with the production of novel AFL phenotypes, this article assesses the diversity of vegetative compatibility reactions in isolates of A. flavus to identify heterokaryon self-incompatible (HSI) strains among nonaflatoxigenic isolates, which would be used as biological controls of AFL contamination in crops. Nitrate nonutilizing (nit) mutants were recovered from 25 A. flavus isolates, and based on vegetative complementation between nit mutants and on the microscopic examination of the number of hyphal fusions, five nonaflatoxigenic (6, 7, 9 to 11) and two nontoxigenic (8 and 12) isolates of A. flavus were phenotypically characterized as HSI. Because the number of hyphal fusions is reduced in HSI strains, impairing both heterokaryon formation and the genetic exchanges with aflatoxigenic strains, the HSI isolates characterized here, especially isolates 8 and 12, are potential agents for reducing AFL contamination in crops. Copyright © International Association for Food Protection.


Rhoden S.A.,State University of Maringá | Garcia A.,State University of Maringá | Santos E Silva M.C.,Laboratorio Of Genetica Of Microrganismos | Azevedo J.L.,Laboratorio Of Genetica Of Microrganismos | Pamphile J.A.,Laboratorio Of Genetica Of Microrganismos
Genetics and Molecular Research | Year: 2015

Various organisms such as fungi and bacteria can live inside plants, inhabiting the aerial parts (primarily the leaves) without causing damage. These microorganisms, called endophytes, produce an extensive variety of compounds that can be useful for medical and agronomic purposes. Trichilia elegans A. Juss., belonging to the Meliaceae family, shows wide dispersion in South America, and phytochemical analyses from these plants and endophyte isolates have shown biological activity. Accordingly, the aim of this study was to verify the diversity of bacterial endophytes from T. elegans using partial sequencing of 16S rRNA, followed by phylogenetic analysis. Isolation was performed by cutting the leaves, after disinfection with 5% sodium hypochlorite (NaOCl), in 1-2-mm2 fragments, which wereequally placed on dishes containing TSA and fungicide BENLATE at 75 μg/mL. All dishes were incubated at 28°C in the biochemical oxygen demand system for 5 days and periodically checked.Afterwards, the colonization frequency (%) was determined: (number of fragments colonized by bacteria/total number of fragments) x 100. Three isolations between September 2011 and March 2012 were performed; the growth frequency ranged between 1.6 and 13.6%. Following sequencing of 16S rRNA and phylogenetic analysis, the genera identified were: Staphylococcus, Bacillus, Microbacterium, Pseudomonas, and Pantoea. These results will provide important knowledge on the diversity of endophytic bacteria inhabiting medicinal plants, and a better understanding of the microbiome of T. elegans would reinforce the necessity of endophyte studies with a focus on their future applications in biotechnological areas of agriculture, medicine, and the environment. © FUNPEC-RP.


Pinto T.S.,Laboratorio Of Genetica Of Microrganismos | De Oliveira C.P.,Laboratorio Of Genetica Of Microrganismos | Da Costa A.C.V.,Laboratorio Of Microbiologia Of Alimentos | Lima C.O.,Laboratorio Of Genetica Of Microrganismos | And 3 more authors.
Natural Product Research | Year: 2013

This study assessed the production of a bacteriocin-like substance by Staphylococcus pseudintermedius S28, and evaluates its inhibitory effect against isolates of S. aureus from foods. All indicator isolates were sensitive to the substance produced from S. pseudintermedius S28, showing growth inhibition zones ranging from 14.2 to 28.3 mm. The inhibitory substance has no effect against the producer strain. The inhibitory substance was affected by proteolytic enzymes, while glycolytic and lipolytic enzymes had no effect, suggesting that the active substance could be considered as a bacteriocin-like substance. From these results, S. pseudintermedius S28 could be an interesting producer of a bacteriocin-like substance capable of strongly inhibiting S. aureus. © 2013 Copyright Taylor and Francis Group, LLC.


Cirino I.C.S.,Laboratorio Of Genetica Of Microrganismos | Menezes-Silva S.M.P.,Laboratorio Of Genetica Of Microrganismos | Silva H.T.D.,Laboratorio Of Genetica Of Microrganismos | De Souza E.L.,Federal University of Paraiba | Siqueira-Junior J.P.,Laboratorio Of Genetica Of Microrganismos
Chemotherapy | Year: 2015

Background: In an ongoing project to evaluate essential oils as modulators of antibiotic resistance, the essential oil from Origanum vulgare L. (OVEO), as well as its individual constituents carvacrol (CAR) and thymol (THY), were investigated using Staphylococcus aureus strains possessing efflux mechanisms of resistance to norfloxacin, erythromycin and tetracycline. Methods: The minimum inhibitory concentration (MIC) values of the antibiotics were determined by agar dilution method, in the absence and in the presence of subinhibitory concentrations of OVEO, CAR or THY. Results: Along with relevant antistaphylococcal activity, OVEO, CAR and THY modulated the activity of tetracycline, i.e. in combination with antibiotics a reduction in the MIC was observed (up to fourfold). Conclusions: The results presented here represent, as far as we know, the first report of OVEO, CAR and THY as putative efflux pump inhibitors. Broadly, these findings indicate that essential oils could serve as potential sources of compounds capable of modulating drug resistance. © 2015 S. Karger AG, Basel.


PubMed | Laboratorio Of Genetica Of Microrganismos
Type: Journal Article | Journal: Natural product research | Year: 2013

This study assessed the production of a bacteriocin-like substance by Staphylococcus pseudintermedius S28, and evaluates its inhibitory effect against isolates of S. aureus from foods. All indicator isolates were sensitive to the substance produced from S. pseudintermedius S28, showing growth inhibition zones ranging from 14.2 to 28.3 mm. The inhibitory substance has no effect against the producer strain. The inhibitory substance was affected by proteolytic enzymes, while glycolytic and lipolytic enzymes had no effect, suggesting that the active substance could be considered as a bacteriocin-like substance. From these results, S. pseudintermedius S28 could be an interesting producer of a bacteriocin-like substance capable of strongly inhibiting S. aureus.

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