140 resultados para fungal pathogens


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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In the United States, composites accounted for nearly 70% of the 173.2 million composite and amalgam restorations placed in 2006 (Kingman et al., 2012), and it is likely that the use of composite will continue to increase as dentists phase out dental amalgam. This trend is not, however, without consequences. The failure rate of composite restorations is double that of amalgam (Ferracane, 2013). Composite restorations accumulate more biofilm, experience more secondary decay, and require more frequent replacement. In vivo biodegradation of the adhesive bond at the composite-tooth interface is a major contributor to the cascade of events leading to restoration failure. Binding by proteins, particularly gp340, from the salivary pellicle leads to biofilm attachment, which accelerates degradation of the interfacial bond and demineralization of the tooth by recruiting the pioneer bacterium Streptococcus mutans to the surface. Bacterial production of lactic acid lowers the pH of the oral microenvironment, erodes hydroxyapatite in enamel and dentin, and promotes hydrolysis of the adhesive. Secreted esterases further hydrolyze the adhesive polymer, exposing the soft underlying collagenous dentinal matrix and allowing further infiltration by the pathogenic biofilm. Manifold approaches are being pursued to increase the longevity of composite dental restorations based on the major contributing factors responsible for degradation. The key material and biological components and the interactions involved in the destructive processes, including recent advances in understanding the structural and molecular basis of biofilm recruitment, are described in this review. Innovative strategies to mitigate these pathogenic effects and slow deterioration are discussed.

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Protocylindrocorpus brasiliensis n. sp. (Diplogastroidea: Cylindrocorporidae) is described from reproductive stages removed from galleries of the ambrosia beetle, Euplatypus parallelus (F.) (Curculionidae: Platypodinae) in Para rubber trees (Hevea brasiliensis) in Brazil. This is the first record of the genus Protocylindrocorpus from the Neotropics. Males of P. brasiliensis are quite striking because their long spicules extend up to 72% of their total body length. The adults exhibit conspecific agglutination where they congregate in a slimy substance that serves to maintain them in a coherent group for mating. Some of the adults were infected by fungal and protozoan pathogens, implying that disease plays a role in regulating natural populations. The discovery of P. brasiliensis provides new information on nematode structure, behavior, and ecology.

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The ants of genus Atta belong to the Attine tribe (order Hymenoptera, family Formicidae, subfamily Myrmicinae) and are commonly known as leaf-cutting ants for having the habit of cutting several vegetable species used as substrate for growing mutualistic fungus (Agaricales: Lepiotaceae). Recent studies showed that, in addition to that, other fungi may occur in the nests in a dorment state or participate in the functioning dynamic of this symbiosis. Researches related to surveys of fungus biodiversity in nests of different Atta species have found important phytopathogenic representatives. In Brazil, studies about integrated management of plagues, developed by Embrapa Meio Ambiente (Embrapa Environment), point out the need of higher investments in projects that involve the phytopathogenic transmission by insects in order to reduce costs to control them or minimize environmental impact. The purpose of this study was to broaden the knowledge about the ecology of these fungi, isolating and identifying species associated with Attine tribe ants, thus understanding the scope of pathogenic and phytopathogenic species spread by these ants. For that reason, gynes were collected from Atta laevigata and Atta capiguara anthills located at Unesp Botucatu (São Paulo, Brazil) campus. In order to isolate the fungus, the mineral oil floating technique was used. The identification of the isolated fungi was done based on microscopic and molecular characteristics using DNA ribosomal sequencing. The most highly abundant genera found so far were: Cladosporium, Exophiala, Penicillium, Acremonium, Phialophora and Teratosphaeria. Representatives of the genera Exophiala, Phialophora and Cladosporium may be human pathogens, whereas Teratosphaeria and Penicillium are related to diseases in Eucalyptus and citric fruits, respectively. The results show that these ants may host important fungal species besides the ones already... (Complete abstract click electronic access below)

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The dimorphic pathogenic fungus, Paracoccidioides brasiliensis (Pb), is the etiological agent of paracoccidioidomycosis (PCM), the most important systemic mycosis in Latin America. While the yeast phase can be isolated from patients affected by paracoccidioidomycosis, dogs and naturally infected armadillos; several elements related to the ecology of the saprophytic phase of the pathogen, which is responsible for the production of infective propagules, are poorly understood, hampering the adoption of preventive measures. The demonstration of the high incidence of Pb infection in the 9- banded armadillo, Dasypus novemcinctus, has opened new perspectives for the identification of the pathogen’s habitat. At the opening of the armadillos’ burrows, spider webs are commonly found. The objective of this study was to evaluate the presence of Pb in spider webs samples related to the habitat of armadillos. Spider web samples were collected at Lageado Farm, Botucatu/SP and prepared for microscopic, molecular and mycological analyses. Microscopic analysis showed that different fungi were closely attached to spider web samples. Nested-PCR reaction showed positive amplification for Pb in 4 samples, with identity confirmed by amplicon sequencing. Fungal colonies also included members of Aspergillus, Blastobotrys, Penicillium, Candida, and Sporothrix genera, which are related to opportunistic disease and primary infections of great medical importance. In vitro adhesion tests of mycelia and yeast form of Pb to the spider webs were also performed, in order to analyze the possible physical attraction between fungal cells and the spider web protein network. The results showed a clear adherence of fungal particles to spider webs. In the current literature, there are no studies reporting adhesive properties of microorganisms to spider webs... (Complete abstract click electronic access below)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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