RESUMO: Endófitos são fungos e bactérias que vivem no interior das plantas sem causar nenhum dano aos seus hospedeiros. Nas últimas décadas o potencial biotecnológico desses micro-organismos tem aumentado com o advento da nanotecnologia. Estudos descobriram que fungos e bactérias são capazes de produzirem nanopartículas por meio de rotas intra ou extracelulares, processo este que passou a ser descrito como micosíntese. O interesse cada vez maior para métodos mais sustentáveis e biológicos resultou no desenvolvimento de nanopartículas nãotóxicas e comparativamente mais bioativas. Ao contrário dos métodos físicos e químicos, a micosíntese é rentável e favorável ao meio ambiente. Neste trabalho buscamos realizar uma revisão de literatura acerta dos microorganismos endofíticos e síntese biológica de nanopartículas. Os gêneros de bactérias endofíticas mais estudados quanto a micosíntese destacam-se Bacillus e Pseudomonas, enquanto para fungos Aspergillus, Penicillium, Fusarium, Colletotrichum, Altrnaria e Trichoderma. Dentre as principais aplicações biotecnológicas destas nanopartículas oriundas da síntese microbiana temos atividades antibacterianas, citotóxicas e antioxidantes. A associação entre endófitos e nanopartículas está em fase exploratória para compreender com clareza os mecanismos responsáveis por essa interação. Entretanto, sabe-se que estas nanopartículas produzidas por meio da micosíntese já são prospectadas em algumas atividades biológicas. Espera-se que todas as espécies de plantas abriguem endófitos, os quais podem ser isolados e bioprospectados para a produção de novas ou já conhecidas nanopartículas. PALAVRAS-CHAVE:Endófitos. Micosíntese. Nanotecnologia. Aplicações biotecnológicas.

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The incidence of female breast cancer has increased; it is the most commonly diagnosed cancer, at 11.7% of the total, and has the fourth highest cancer-related mortality. Magnetic nanoparticles have been used as carriers to improve selectivity and to decrease the side effects on healthy tissues in cancer treatment. Iron oxide (mainly magnetite, Fe3O4), which presents a low toxicity profile and superparamagnetic behavior, has attractive characteristics for this type of application in biological systems. In this article, synthesis and characterization of magnetite (NP-Fe3O4) and silica-coated magnetite (NP-Fe3O4/SiO2) nanoparticles, as well as their biocompatibility via cellular toxicity tests in terms of cell viability, are carefully investigated. MCF-7 cells, which are commonly applied as a model in cancer research, are used in order to define prognosis and treatment specifics at a molecular level. In addition, HaCaT cells (immortalized human keratinocytes) are tested, as they are normal, healthy cells that have been used extensively to study biocompatibility. The results provide insight into the applicability of these magnetic nanoparticles as a drug carrier system. The cytotoxicity of nanoparticles in breast adenocarcinoma (MCF-7) and HaCat cells was evaluated, and both nanoparticles, NP-Fe3O4/SiO2 and NP-Fe3O4, show high cell viability (non-cytotoxicity). After loading the anti-tumor drug doxorubicin (Dox) on NP-Fe3O4/Dox and NP-Fe3O4/SiO2/Dox, the cytotoxicity against MCF-7 cells increases in a dose-dependent and time-dependent manner at concentrations of 5 and 10 μg/mL. HaCat cells also show a decrease in cell viability; however, cytotoxicity was less than that found in the cancer cell line. This study shows the biocompatibility of NP-Fe3O4/SiO2 and NP-Fe3O4, highlighting the importance of silica coating on magnetic nanoparticles and reinforcing the possibility of their use as a drug carrier system against breast adenocarcinoma cells (MCF-7).

The effect of farnesol, a sesquiterpene alcohol, on the production of laccases by Trametes versicolor and Pycnoporus sanguineus in pineapple waste solid-state fermentation was evaluated. Extracellular laccase production reached a maximum of 77.88 ± 5.62 U/g (236% above control) in farnesol-induced cultures of T. versicolor on the 17th day, whereas in a similar P. sanguineus culture, a maximal laccase activity of 130.95 ± 2.20 U/g (159% increase) was obtained on the 17th day. A single 45 KDa laccase was produced by both fungi under the influence of farnesol. These and other data allow us to conclude that farnesol acted as an inducer of the same form of laccase in both fungi. Farnesol disfavored fungal growth by increasing the lag phase, but it also clearly improved the oxidative state of the cultures. Contrary to the results obtained previously in submerged cultures, farnesol did not promote hyperbranching in the fungal mycelia. This is the first demonstration that farnesol is an excellent inducer of laccases in T. versicolor and P. sanguineus in solid-state cultivation. In quantitative terms, the results can be regarded as an excellent starting point for developing industrial or at least pre-industrial procedures to produce laccases using T. versicolor and P sanguineus under the stimulus of farnesol.

The use of a variety of microorganisms for the degradation of chemicals is a green solution to the problem of environmental pollution. In this work, fungi–magnetic nanoparticles were studied as systems with the potential to be applied in environmental remediation and pest control in agriculture. High food demand puts significant pressure on increasing the use of herbicides, insecticides, fungicides, pesticides, and fertilizers. The global problem of water pollution also demands new remediation solutions. As a sustainable alternative to commercial chemical products, nanobiocomposites were obtained from the interaction between the fungus M. anisopliae and two different types of magnetic nanoparticles. Fourier transform infrared spectroscopy, optical and electron microscopy, and energy dispersive spectroscopy were used to study the interaction between the fungus and nanoparticles, and the morphology of individual components and the final nanobiocomposites. Analyses show that the nanobiocomposites kept the same morphology as that of the fungus in natura. Magnetic measurements attest the magnetic properties of the nanobiocomposites. In summary, these nanobiocomposites possess both fungal and nanoparticle properties, i.e., nanobiocomposites were obtained with magnetic properties that provide a low-cost approach benefiting the environment (nanobiocomposites are retrievable) with more efficiency than that of the application of the fungus in natura.

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