Efeitos de nanopartículas de prata biossintetizadas por Aspergillus niger em diferentes níveis tróficos
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Data
2020-03-18
Autores
Ribeiro, Bruna Marques
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Universidade Estadual Paulista (Unesp)
Resumo
A utilização de nanopartículas de prata (AgNP) biológicas nos dias atuais é uma alternativa promissora frente as obtidas por via sintética (VS), uma vez que, não geram resíduos em seu processo de síntese e possuem superfície revestida por proteínas que viabilizam sua incorporação em diversos compostos comerciais, sendo os fármacos os de maior destaque. O efeito do descarte de AgNP sintéticas no meio ambiente é atualmente fonte de investigação de diversos grupos de pesquisa, entretanto, são restritas as informações associadas as AgNP biológicas. Diante deste contexto, o presente estudo utilizou a AgNP IBCLP20 biossintetizada pelo fungo Aspergillus niger para avaliar a sua ação antimicrobiana e efeito tóxico em ambiente aquático dulcícula utilizando organismos pertencentes a diferentes níveis tróficos. Nos ensaios antimicrobianos a AgNP IBCLP20 apresentou excelente ação antibacteriana em uma faixa de concentração de 5 a 100 µg/mL e ação antifúngica na faixa de concentração de 20 a 100 µg/mL. A densidade celular da microalga Chrorella vulgaris, quando exposta a AgNP IBCLP20 e ao sal precursor AgNO3, na maior concentração analisada (100 uM/mL) e após 96 horas de incubação, apresentou uma taxa de redução de 34,4% e 85,71%, respectivamente. Nas mesmas condições supracitadas, só foi detectada viabilidade celular da microalga quando exposta a AgNP biológica (65,38%). A letalidade média em D. silimis causada pelas AgNP IBCLP20 foi estimada a uma concentração de 4,06 μg/L (2,29 -6,42). , Utilizou-se também, os biomarcadores fisiológicos consumo de oxigênio e excreção de amônia como respostas as alterações no metabolismo no peixe Danio rerio exposto AgNP IB-CLP20, AgNP comercial e AgNO3. A exposição a AgNP IBCLP20 ocasionou aumento significativo (p<0,05) do consumo de oxigênio pelo D. rerio de aproximadamende 200% na maior concentração estudada (75 µg/L). A excreção de amônia apresentou um aumento nas concentrações iniciais de exposição, chegando a elevar-se duas vezes quando comparada ao controle, seguida por uma queda nas concentrações mais elevadas. Para AgNP comercial o consumo de O2 não apresentou diferenças significativas e a excreção de amônia apresentou uma queda em todas as concentrações. Para AgNO3 o metabolismo apresentou um aumento nas primeiras concentrações chegando a aproximadamente 300% o consumo do controle, seguido por uma queda nas demais concentrações e a excreção de amônia apresentou um decréscimo em todas as concentrações analisadas.
The use of biological silver nanoparticles (AgNP) today is a promising alternative compared to those obtained synthetically (VS), since they do not generate residues in their synthesis process and have a surface coated with proteins that enable their incorporation in several commercial compounds, with drugs being the most prominent. The effect of discarding synthetic AgNP in the environment is currently a source of investigation for several research groups, however, information associated with biological AgNP is restricted. In this context, the present study used the AgNP IBCLP20 biosynthesized by the fungus Aspergillus niger to evaluate its antimicrobial action and toxic effect in aquatic dulcicle environment using organisms belonging to different trophic levels. In antimicrobial tests, AgNP IBCLP20 showed excellent antibacterial action in a concentration range of 5 to 100 µg / mL and antifungal action in the concentration range of 20 to 100 µg / mL. The cell density of the microalgae Chrorella vulgaris, when exposed to AgNP IBCLP20 and the precursor salt AgNO3, in the highest concentration analyzed (100 uM / mL) and after 96 hours of incubation, showed a reduction rate of 34.4% and 85.71 %, respectively. Under the same conditions mentioned above, cell viability of the microalgae was only detected when exposed to biological AgNP (65.38%). The average lethality in D. silimis caused by AgNP IBCLP20 was estimated at a concentration of 4.06μg/L (2.29 -6.42). , The physiological biomarkers oxygen consumption and ammonia excretion were also used as responses to changes in metabolism in exposed fish Danio rerio AgNP IB-CLP20, commercial AgNP and AgNO3. Exposure to AgNP IBCLP20 caused a significant increase (p <0.05) in oxygen consumption by D. rerio of approximately 200% at the highest concentration studied (75µg/L). The excretion of ammonia showed an increase in the initial exposure concentrations, reaching an increase twice when compared to the control, followed by a decrease in the higher concentrations. For commercial AgNP, O2 consumption did not show significant differences and ammonia excretion decreased in all concentrations. For AgNO3, metabolism showed an increase in the first concentrations reaching approximately 300% of the control consumption, followed by a drop in the other concentrations and the excretion of ammonia showed a decrease in all the analyzed concentrations.
The use of biological silver nanoparticles (AgNP) today is a promising alternative compared to those obtained synthetically (VS), since they do not generate residues in their synthesis process and have a surface coated with proteins that enable their incorporation in several commercial compounds, with drugs being the most prominent. The effect of discarding synthetic AgNP in the environment is currently a source of investigation for several research groups, however, information associated with biological AgNP is restricted. In this context, the present study used the AgNP IBCLP20 biosynthesized by the fungus Aspergillus niger to evaluate its antimicrobial action and toxic effect in aquatic dulcicle environment using organisms belonging to different trophic levels. In antimicrobial tests, AgNP IBCLP20 showed excellent antibacterial action in a concentration range of 5 to 100 µg / mL and antifungal action in the concentration range of 20 to 100 µg / mL. The cell density of the microalgae Chrorella vulgaris, when exposed to AgNP IBCLP20 and the precursor salt AgNO3, in the highest concentration analyzed (100 uM / mL) and after 96 hours of incubation, showed a reduction rate of 34.4% and 85.71 %, respectively. Under the same conditions mentioned above, cell viability of the microalgae was only detected when exposed to biological AgNP (65.38%). The average lethality in D. silimis caused by AgNP IBCLP20 was estimated at a concentration of 4.06μg/L (2.29 -6.42). , The physiological biomarkers oxygen consumption and ammonia excretion were also used as responses to changes in metabolism in exposed fish Danio rerio AgNP IB-CLP20, commercial AgNP and AgNO3. Exposure to AgNP IBCLP20 caused a significant increase (p <0.05) in oxygen consumption by D. rerio of approximately 200% at the highest concentration studied (75µg/L). The excretion of ammonia showed an increase in the initial exposure concentrations, reaching an increase twice when compared to the control, followed by a decrease in the higher concentrations. For commercial AgNP, O2 consumption did not show significant differences and ammonia excretion decreased in all concentrations. For AgNO3, metabolism showed an increase in the first concentrations reaching approximately 300% of the control consumption, followed by a drop in the other concentrations and the excretion of ammonia showed a decrease in all the analyzed concentrations.
Descrição
Palavras-chave
Nanopartículas de prata micogênica, Klebsiella pneumoniae, Trichophyton mentagrophytes, Chrorella vulgaris, Daphnia similis, Danio rerio, Nanopartículas