ABSTRACT. Tolerance to Polycyclic Hydrocarbons Aromatic (PAHs) is considered an important characteristic when assessing the bioremediation potential of microorganisms. Given this, the objective of this research was to assay filamentous fungi from the Amazon region, isolated from sediments with differents levels of contamination by PAHs, for tolerance to phenanthrene and pyrene. To achieve this, fungal cultures plugs (5 mm), obtained after 7 days growth, were transferred to petri dishes containing 20% Sabouraud dextrose agar medium, after surface innoculation with phenanthrene and pyrene crystals, separately. Radial mycelial growth was evaluated after 10 days at five different concentration levels for each contaminant and control group, all in triplicate for each treatment. Fungal growth and growth inhibition rates were calculated. The average growth of the colonies in each treatment was compared with one-way ANOVA, followed by a Tukey Test (p < 0,05). All fungi showed tolerant to phenanthrene and pyrene. However, Hypoxylon sp. showed the lowest growth inhibition rate and average growth rates significantly different of the other six tested species. Hypoxylon sp. has been shown to be a promising genetic resource for use in new studies of PAHs degradation.Keywords: phenanthrene, pyrene, fungal growth inhibition, Amazon.Tolerância a Hidrocarbonetos Policíclicos Aromáticos (HPAs) por fungos filamentosos isolados de sedimentos contaminados da região Amazônica RESUMO. A tolerância a Hidrocarbonetos Policíclicos Aromática (HPAs) é considerada como uma característica importante na avaliação do potencial de micro-organismos para biorremediação. Diante disso, o objetivo desta pesquisa foi avaliar fungos filamentosos da região amazônica, isolados de sedimentos com diferentes níveis de contaminação por HPAs, quanto à tolerância ao fenantreno e pireno. Para tanto, discos das culturas fúngicas (5 mm), obtidas após 7 dias de crescimento, foram transferidas para placas de Petri contendo meio Agar Sabouraud Dextrose a 20%, após inoculação superficial com cristais de fenantreno e pireno, separadamente. O crescimento micelial radial foi avaliado após 10 dias em cinco concentrações diferentes para cada contaminante e grupo controle, ambos em triplicata para cada tratamento. As taxas de crescimento fúngico e de inibição de crescimento foram calculadas. O crescimento médio das colônias em cada tratamento foi comparado com ANOVA one way, seguido pelo teste de Tukey (p < 0,05). Todos os fungos mostraram tolerância ao fenantreno e ao pireno. No entanto, Hypoxylon sp. apresentou menor taxa de inibição de crescimento e taxas médias de crescimento significativamente diferentes das outras seis espécies testadas. Hypoxylon sp. tem se mostrado um recurso genético promissor para uso em novos estudos sobre degradação de HPAs.Palavras-chaves: fenantreno, pireno, inibição do crescimento fúngico, Amazônia.
ABSTRACT. Baetidae (Insecta, Ephemeroptera) of Cerrado streams in the state of Mato Grosso, Brazil, under different levels of environmental preservation. The effect of different stream environmental preservation levels, in 1 st to 4 th orders, over the richness, abundance, similarity in the composition and the potential of Baetidae (Ephemeroptera) species as bioindicators were investigated in a Cerrado region located in the state of Mato Grosso, Brazil. A total of twenty species/morphospecies were catalogued from the 1752 samples of nymphs, resulting in a new record for two species in Brazil. Values of Habitat Integrity Index (HII) were categorized among damaged, modified, and preserved environments. Species richness was different between sites, being greater in disturbed habitats. Total abundance was higher among preserved and altered environments, and differed significantly from the degraded areas. The NMDS analysis indicates that, in preserved and modified sites, the similarity in the composition of species differs from degraded areas. Four species showed a positive relationship with increasing values of HII. Baetidae showed environmental indicator species with different levels of preservation, with Zelusia principalis
Polycyclic aromatic hydrocarbons (PAHs) were identified and quantified in samples of superficial sediments of the Negro River, in the Amazon region of Brazil, through analyses performed by GC/MS. Total PAH concentration that includes parent and alkylated PAHs ranged from 6.5 to 5348 ng g -1 of dry weight. The ∑16 PAHs prioritized in environmental studies by the U.S. Environmental Protection Agency (USEPA) ranged from 5.6 to 1187 ng g -1 . The most contaminated places were those where muddy sediments were found, with the highest concentrations of organic matter, carbon and total nitrogen. The priority PAHs with high molecular weight represented 70% of the total abundance and showed that the main source of contamination of the sediments was pyrogenic. However, petrogenic PAHs coming from oil and derivatives input is also an important contamination source to be considered. ]]>
RESUMO: Este trabalho objetivou avaliar o efeito da adubação foliar em milho RR, após diferentes formas de aplicação de glifosato, associado ou não a outro herbicida. O delineamento experimental utilizado foi o de blocos ao acaso, com 12 tratamentos e 4 repetições, sendo implantado em arranjo fatorial 3x4 (três manejos de aplicação de herbicidas e quatro doses de adubo foliar). Os manejos e combinações de herbicidas foram constituídos por uma aplicação de glifosato (1440 g e. a. ha-1), duas aplicações de glifosato, sendo a segunda 14 dias após (1440 + 1440 g e. a. ha-1), e glifosato + atrazina (1440 g e. a. ha-1 + 1500 g i. a. ha-1). A adubação foliar foi realizada 7 dias após a aplicação dos herbicidas utilizando doses de 0; 0,5; 1 e 1,5 L ha-1 de um fertilizante líquido multinutriente. Os parâmetros avaliados foram índice de cor verde, altura de planta e de inserção da espiga principal, massa de 100 grãos, produtividade, e teor de nutriente foliar. Observando-se uma redução na concentração de Fe foliar com duas aplicações de glifosato. O uso do adubo foliar não influenciou nas características agronômicas e nutricionais avaliadas. Palavra-chave: Zea mays, transgênicos, nutrição de plantas, produtividade.
In order to assess the effectiveness of
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