Navegando por Autor "Kasuya, Maria Catarina M."
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Item Ammonium removal from high-salinity oilfield-produced water: assessing the microbial community dynamics at increasing salt concentrations(Appl Microbiol Biotechnol, 2016-11-04) Quartaroli, Larissa; Silva, Lívia C. Fidélis; Silva, Claudio Mudadu; Lima, Helena Santiago; Paula, Sergio Oliveira de; Oliveira, Valéria Maia de; Silva, Marliane de Cássia S. da; Kasuya, Maria Catarina M.; Sousa, Maíra Paula de; Torres, Ana Paula R.; Souza, Rodrigo Suhett; Bassin, João Paulo; Silva, Cynthia Canêdo daWater generated during oil exploration is chemically complex and contains high concentrations of ammonium and, in some cases, high salinity. The most common way to remove ammonium from effluent is a biological process, which can be performed by different routes and different groups of microorganisms. However, the presence of salts in the effluents could be an inhibiting factor for biological processes, interfering directly with treatment. This study aimed to evaluate changes in the profile of a microbial community involved in the process of ammonium removal when subjected to a gradual increase of salt (NaCl), in which the complete inhibition of the ammonium removal process occurred at 125 g L−1 NaCl. During the sludge acclimatization process, samples were collected and submitted to denaturing gradient gel electrophoresis (DGGE) and massive sequencing of the 16S ribosomal RNA (rRNA) genes. As the salt concentration increased in the reactor, a change in the microbial community was observed by the DGGE band profiles. As a result, there was a reduction in the presence of bacterial populations, and an increase in archaeal populations was found. The sequencing data suggested that ammonium removal in the reactor was carried out by different metabolic routes by autotrophic nitrifying bacteria, such as Nitrosococcus, Nitrosomonas, Nitrosovibrio, Nitrospira, and Nitrococcus; ammonium-oxidizing archaea Candidatus nitrosoarchaeum; ANAMMOX microorganisms, such as Candidatus brocadia, Candidatus kuenenia, and Candidatus scalindua; and microorganisms with the potential to be heterotrophic nitrifying, such as Paracoccus spp., Pseudomonas spp., Bacillus spp., Marinobacter sp., and Alcaligenes spp.Item Antioxidant activities, total phenolics and metal contents in Pleurotus ostreatus mushrooms enriched with iron, zinc or lithium(LWT - Food Science and Technology, 2013-12) Assunção, Laélia Soares de; Vieira, Patrícia A. Fontes; Gontijo, Douglas C.; Vieira, Breno César; Fontes, Edimar A. F.; Leite, João Paulo V.; Oliveira, Maria Goreti de Almeida; Kasuya, Maria Catarina M.Food enrichment with minerals has been a method of increasing health benefits. Edible Pleurotus ostreatus mushrooms are a source of dietary elements and antioxidants. In this work, the phenolic content, antioxidant activity and metal content of P. ostreatus grown on coffee husk, enriched with iron (Fe), zinc (Zn) and lithium (Li) were investigated. The content of phenolic compounds was found to be different in mushroom enriched with Fe, Zn or Li. In DPPH test, a difference was observed in antioxidant activity; however, no difference in this activity was observed using β-carotene/linoleic acid test. The enrichment with minerals promoted decrease in the content of Fe in three enriched samples. There was no change in the content of Zn in the samples. Observed the accumulation of Li in the sample enriched with LiCl and P. ostreatus enriched with Fe, Zn or Li provided minerals such as K, P, Fe, Zn, Li and Cu. In addition, no heavy metals such as Ni, Cr and Cd were detected, and only low levels of Pb and Al were observed. The study was the first report to demonstrate the understanding of how mineral supplementation reduces antioxidant activity in P. ostreatus enriched with iron, zinc or lithium.Item Diversity of fungi associated with Atta bisphaerica (Hymenoptera: Formicidae): the activity of Aspergillus ochraceus and Beauveria bassiana(Psyche: A Journal of Entomology, 2011-10-24) Ribeiro, Myriam M. R.; Amaral, Karina D.; Seide, Vanessa E.; Souza, Bressane M. R.; Della Lucia, Terezinha M. C.; Kasuya, Maria Catarina M.; Souza, Danival J. deThe grass-cutting ant Atta bisphaerica is one of the most serious pests in several pastures and crops in Brazil. Fungal diseases are a constant threat to these large societies composed of millions of closely related individuals. We investigated the occurrence of filamentous fungi associated with the ant A. bisphaerica in a pasture area of Vic ̧osa, Minas Gerais State, Brazil. Several fungi species were isolated from forager ants, and two of them, known as entomopathogenic, Beauveria bassiana and Aspergillus ochraceus, were tested against worker ants in the laboratory. The two species were highly virulent, achieving 50 percent worker mortality within 4-5 days. It is the first time A. ochraceus, a commonly found fungal species, is reported to infect Atta species at a high prevalence. Possible uses for the fungus within biological control are discussed.Item A pH signaling mechanism involved in the spatial distribution of calcium and anion fluxes in ectomycorrhizal roots(New Phytologist, 2009-01) Ramos, Alessandro C.; Lima, Pedro T.; Dias, Pedro N.; Kasuya, Maria Catarina M.; Feijó, José A.Mycorrhization is a typical example of a host–pathogen symbiotic interaction where the pathogen cell biology and the host immune response coevolved several functional links. Here, the role played by ion fluxes across the root concerning nutrient uptake, osmoregulation, growth and signaling events is addressed. An ion‐selective vibrating probe system was used to determine the net fluxes of protons (H+), calcium (Ca2+) and anions (A−) along nonmycorrhizal and ectomycorrhizal (ECM) roots of Eucalyptus globulus colonized by Pisolithus sp. These data show that, from five root zones analyzed, the main effect of fungal colonization was localized to the elongation zone. Here, strong changes in ion dynamics and rhizosphere acidification capacity were observed. Additionally, ion fluxes exhibited periodic fluctuations. To verify whether these fluctuations corresponded to sustained oscillations, continuous wavelet time spectrum analysis was applied and it was determined that H+ and A− fluxes from ECM roots had longer periods than nonmycorrhizal roots. By contrast, Ca2+ oscillations were completely abolished following fungal interaction. These results are interpreted in the light of a working model in which nutrient uptake and stimulation of growth are mediated by ECM fungi and may be pH‐dependent. Furthermore, the variations detected in ECM roots for H+ and A− fluxes suggest a main contribution from the plant, while the results obtained for Ca2+ point to a significant involvement of the fungus.Item Polymorphism in the internal transcribed spacer (ITS) of the ribosomal DNA of 26 isolates of ectomycorrhizal fungi(Genetics and Molecular Biology, 2002) Gomes, Eliane A.; Kasuya, Maria Catarina M.; Barros, Everaldo G. de; Borges, Arnaldo C.; Araújo, Elza F.Inter- and intraspecific variation among 26 isolates of ectomycorrhizal fungi belonging to 8 genera and 19 species were evaluated by analysis of the internal transcribed sequence (ITS) of the rDNA region using restriction fragment length polymorphism (RFLP). The ITS region was first amplified by polymerase chain reaction (PCR) with specific primers and then cleaved with different restriction enzymes. Amplification products, which ranged between 560 and 750 base pairs (bp), were obtained for all the isolates analyzed. The degree of polymorphism observed did not allow proper identification of most of the isolates. Cleavage of amplified fragments with the restriction enzymes Alu I, Hae III, Hinf I, and Hpa II revealed extensive polymorphism. All eight genera and most species presented specific restriction patterns. Species not identifiable by a specific pattern belonged to two genera: Rhizopogon (R. nigrescens, R. reaii, R. roseolus, R. rubescens and Rhizopogon sp.), and Laccaria (L. bicolor and L. amethystea). Our data confirm the potential of ITS region PCR-RFLP for the molecular characterization of ectomycorrhizal fungi and their identification and monitoring in artificial inoculation programs.Item Tolerance of Bradyrhizobium strains to glyphosate formulations(Crop Protection, 2005-01) Santos, José Barbosa dos; Ferreira, Evander Alves Ferreira a; Kasuya, Maria Catarina M.; Silva, Antonio Alberto da; Procópio, Sergio de OliveiraApplication of glyphosate to soybean plants, resistant to this herbicide, may be harmful to Bradyrhizobium, the symbiotic bacterium. This study compared the effect of two glyphosate commercial formulations, ZappQi® and Roundup Transorb® with the standard N-(phosphonomethyl) glycine on the growth of four Bradyrhizobium strains under laboratory conditions. Commercial formulations were applied at a concentration of 43.2 μg L−1 of a.e. and the strains were inoculated in yeast extract mannitol (YEM) broth used with or without a mixture of aromatics amino acids (phenylalanine, tyrosine, tryptophan). Herbicide effect on the growth of the Bradyrhizobium strains was assessed by optical density reading in a spectrophotometer. Roundup Transorb® had the biggest effects, probably, because of the presence of ethylamine as a surfactant. Pure glyphosate had minimal effects on Bradyrhizobium strains when aromatics amino acids have been added to YEM broth. Glyphosate application as Roundup Transorb® in the initial stage of soybean development may affect the nodulation process by Bradyrhizobium.