Microbiologia
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11840
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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 Basidiosporogenesis, meiosis, and post-meiotic mitosis in the ectomycorrhizal fungus Pisolithusmicrocarpus(Fungal Genetics and Biology, 2010-03-03) Campos, André Narvaes da Rocha; Costa, Maurício DutraPisolithus microcarpus (Cooke and Massee) G. Cunn. is a model organism for the studies on the ecology, physiology, and genetics of the ectomycorrhizal associations. However, little is known about the basidiosporogenesis in this species and, in particular, the nuclear behavior after karyogamy. In this work, the events involved in basidiosporogenesis and meiosis in P. microcarpus were analyzed using fluorescence and scanning electron microscopy. The basidia are formed inside peridioles by the differentiation of the cells along the whole hyphae. Basidial cells measure 12–18 μm in length and 6–7 μm in diameter. P. microcarpus produces eight basidiospores per basidium imbibed in a gelatinous matrix in the basidiocarp. The basidiospores are globose, equinate, with blunt spines, and measure 6–8 μm. Karyogamy can take place inside basidia as well as in undifferentiated hyphal cells followed by nuclear migration to a newly developed basidium where meiosis takes place. After the formation of the meiotic tetrad, one round of post-meiotic mitosis occurs, resulting in the production of eight nuclei per basidium. The newly-formed nuclei migrate into the basidiospores asynchronously, resulting in the production of eight uninucleate spores. This corresponds to pattern A of post-meiotic mitosis. This work is the first report on meiosis and post-meiotic mitosis during basidiosporogenesis in P. microcarpus and contributes to clarify some aspects of the biology and genetics of this ectomycorrhizal species.Item Biosurfactant, solvents and polymer production by Bacillus subtilis RI4914 and their application for enhanced oil recovery(Fuel, 2016-09-15) Fernandes, P. L.; Rodrigues, E. M.; Paiva, F. R.; Ayupe, B. A. L.; McInerney, M. J.; Tótola, M. R.Effects of nutritional and physicochemical parameters on the production of biosurfactants by Bacillus subtilis RI4914 were evaluated. Effects of three different concentrations of NH4NO3 and/or yeast extract were tested. The treatment with 2.0 g l−1 of NH4NO3 without yeast extract resulted in the highest biosurfactant, organic acid, solvent and polymer concentrations, and this cultivation condition was selected for the residual oil recovery experiments. The lower interfacial tension between crude oil and the culture supernatant was 0.07 mN/m and this result was achieved at NaCl concentrations up to 120 g l−1. Culture fluid with 600 mg l−1 biosurfactant and the polymer produced by the bacterium resulted in residual oil recoveries up to 88%. The attainment of low interfacial tensions and high oil recoveries with the biosurfactant concentrations used at high salinity and temperature indicated that B. subtilis RI4914 is an excellent candidate for application in MEOR.Item Desulfovibrio alaskensis prophages and their possible involvement in the horizontal transfer of genes by outer membrane vesicles(Gene, 2019-06) Crispim, Josicelli Souza; Dias, Roberto Sousa; Laguardia, Clara Nogueira; Araújo, Larissa Cristina; Silva, Jéssica Duarte da; Vidigal, Pedro Marcus Pereira; Sousa, Maíra Paula de; Silva, Cynthia Canêdo da; Santana, Mateus Ferreira; Paula, Sérgio Oliveira de; Sousa, Maíra Paula deDesulfovibrio alaskensis is a Gram-negative bacterial species that belongs to the group of Sulphate Reducing Bacteria (SRB) and presents prophages in genomes, a common characteristic of the genus Desulfovibrio. Genetic material can be transported by outer membrane vesicles, however, no data regarding the production of these vesicles has been reported for D. alaskensis. To verify the expression of D. alaskensis prophages and their involvement with outer membrane vesicles, the DSM16109 strain was used. The DSM16109 strain had three prophages and presented reduced growth after mitomycin C addition when compared to the control culture. This reduction was accompanied by the presence of virus-like particles (VLPs), indicating mitomycin C dependent prophage induction. The increase in the number of cap gene copies and transcriptions of the three prophages was verified in the control sample, however, without the formation of VLPs. Prophage genes were identified in outer membrane vesicles from cultures treated and not treated with mitomycin C. DSM16109 prophages are expressed spontaneously but only in the presence of mitomycin C was it possible to observe VLP formation. Due to the genetic material detection from the prophages within outer membrane vesicles, this property may be related to the horizontal transfer of viral genes.Item Microbial diversity and bioremediation of rhizospheric soils from Trindade Island - Brazil(Journal of Environmental Management, 2019-04-15) Camacho-Montealegre, Celia Marcela; Rodrigues, Edmo Montes; Tótola, Marcos RogérioPristine environments may harbor complex microbial communities with metabolic potential for use in bioremediation of organic pollutants. This study aimed to evaluate crude oil biodegradation by microbial communities present in rhizospheric soils of Bulbostylis nesiotis and Cyperus atlanticus on Trindade Island and the compositional structure of these communities. After 60 days under aerobic conditions, Total Petroleum Hydrocarbon biodegradation ranged from 66 to 75%, depending on the plant species and the origin of the soil samples. There was no response of petroleum biodegradation to fertilization with N:P:K (80:160:80 mg dm−3). Soil contamination with crude oil did not necessarily reduce microbial diversity. The richness and diversity increased in contaminated soils in some specific situations. We conclude that microbial communities from pristine soils have the ability to remove hydrocarbons through biodegradation and that Bulbostylis nesiotis and Cyperus atlanticus inhabiting Trindade Island harbor rhizospheric microbial communities with potential for application in rhizoremediation.Item Relative importance of soil physico-chemical characteristics and plant species identity to the determination of soil microbial community structure(Applied Soil Ecology, 2015-07) Bonduki, Victor Hugo A.; Melo, Christiane Augusta D.; Tótola, Marcos R.; Ferreira, Francisco A.; Costa, Maurício Dutra; Massenssini, André M.The structure of soil microbial communities is affected by biotic and abiotic environmental factors, such as plant community composition and soil chemical characteristics, among others. However, little is known about the relative importance of these factors on soil microbial community structure. The objective of this study was to verify which factor, soil chemical characteristics or plant species identity, is more important to the determination of soil microbial community structure. For this, a factorial experiment with four soil chemical conditions and five plant species were set in a greenhouse. After 80 days of cultivation, the rhizospheric soil microbial community structure was accessed by a multiplex T-RFLP, and the mycorrhizal colonization of roots and plant shoot dry mass were estimated. Plant species showed similar growth responses to different soil chemical conditions, but exhibited different patterns in the control of root mycorrhizal colonization. A principal component analysis (PCA) was performed using the T-RFLP data set and showed that soil chemical condition is the main factor defining the structure of soil microbial community. Archaeal and bacterial communities showed to be more sensitive to changes in the soil chemical environment, suggesting a greater importance of these microbial groups in plant adaptation.