Impact of nickel oxide nanoparticles on yeast physiology

[Excerpt] In the recent years, nickel oxide (NiO) nanoparticles (NPs), have been used in different fields, such as in biosensors, catalysis, ceramics, electrochromic film, electronics, conductive and magnetic materials, energy storage devices, fuel cells, printing inks and wastewater treatment [1-2]. Due to the increasing use of these NPs, concerns about their possible toxic effects have been raised. In the present study, the yeast Saccharomyces cerevisiae was used as a cell model to evaluate the possible hazards of NiO NPs. Physicochemical characteristics of NiO in MES buffer, namely NPs agglomeration (examined by dynamic light scattering – DLS), surface charge (determination of zeta potential) and dissolution of the NPs (quantification of Ni2+ released in medium) were evaluated in order to be correlated with their toxicity. [...]info:eu-repo/semantics/publishedVersio

Nickel oxide nanoparticles induce toxicity in yeasts via oxidative stress

[Excerpt] The increasing use of nickel oxide (NiO) nanoparticles (NPs) raises concerns about their potential toxicity. In the present study, the yeast Saccharomyces cerevisiae was used, as a cell model, in order to elucidate whether the toxicity of NiO NPs is associated with the oxidative stress (OS). In abiotic conditions (cell free), NiO NPs were unable to induce the generation of reactive oxygen species (ROS), which excludes the possibility of exerting a pro-oxidant effect. However, yeast cells exposed to NiO NPs accumulated intracellularly superoxide anions (assessed with dihydroethidium) and hydrogen peroxide (evaluated with 2′,7′-dichlorodihydrofluorescein diacetate or dihydrorhodamine 123) when incubated in normal (oxygen) atmosphere. Yeast cells exposed to NiO also presented reduced cell viability (measured through a clonogenic assay). Yeasts co-exposed to NiO NPs and the antioxidants L-ascorbic acid (a scavenger of free radicals) or N-tertbutyl-α-phenylnitrone (a spin trapping agent) presented ROS quenching and increased cell viability, which suggests that NiO toxicity is linked to ROS production. [...]info:eu-repo/semantics/publishedVersio

Editorial: Bio-based solutions for sustainable development of agriculture

In summary, this Research Topic comprises a collection of 16 articles that offer new and updated knowledge about biofertilizers, biocontrol and improved resilience to environmental stressors. The information presented can be useful in the future development of bio-based products that are expected to be used, as an alternative to current agrochemicals, in modern and more sustainable agriculture.ES and HS are grateful to the Portuguese Foundation for Science and Technology (FCT) for financial support, funded by national funds through the FCT/MCTES (PIDDAC), under the scope of the strategic funding of UIDB/04469/2020 (Centre of Biological Engineering, University of Minho) and UIDB/50006/2020 (Associated Laboratory for Green Chemistry - Clean Technologies and Processes, LAQV-REQUIMTE) unit, respectively.info:eu-repo/semantics/publishedVersio

Metal(loid) oxide (Al2O3, Mn3O4, SiO2 and SnO2) nanoparticles cause cytotoxicity in yeast via intracellular generation of reactive oxygen species

In this work, the physicochemical characterization of five (Al2O3, In2O3, Mn3O4, SiO2 and SnO2) nanoparticles (NPs) was carried out. In addition, the evaluation of the possible toxic impacts of these NPs and the respective modes of action were performed using the yeast Saccharomyces cerevisiae. In general, in aqueous suspension, metal(loid) oxide (MOx) NPs displayed an overall negative charge and agglomerated; these NPs were practically insoluble (dissolution <\thinspace8\\%) and did not generate detectable amounts of reactive oxygen species (ROS) under abiotic conditions. Except In2O3 NPs, which did not induce an obvious toxic effect on yeast cells (up to 100 mg/L), the other NPs induced a loss of cell viability in a dose-dependent manner. The comparative analysis of the loss of cell viability induced by the NPs with the ions released by NPs (NPs supernatant) suggested that SiO2 toxicity was mainly caused by the NPs themselves, Al2O3 and SnO2 toxic effects could be attributed to both the NPs and the respective released ions and Mn3O4 harmfulness could be mainly due to the released ions. Al2O3, Mn3O4, SiO2 and SnO2 NPs induced the loss of metabolic activity and the generation of intracellular ROS without permeabilization of plasma membrane. The co-incubation of yeast cells with MOx NPs and a free radical scavenger (ascorbic acid) quenched intracellular ROS and significantly restored cell viability and metabolic activity. These results evidenced that the intracellular generation of ROS constituted the main cause of the cytotoxicity exhibited by yeasts treated with the MOx NPs. This study highlights the importance of a ROS-mediated mechanism in the toxicity induced by MOx NPs.This work was performed in the framework of the financingby Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte and LAQV (UID/QUI/50006/2019)with funding from FCT/MCTES through national funds.info:eu-repo/semantics/publishedVersio

Comment on ``BCS to Bose-Einstein crossover phase diagram at zero temperature for a d_{x^2-y^2} order parameter superconductor: Dependence on the tight-binding structure''

The work by Soares et al. [Phys. Rev. B 65, 174506 (2002)] investigates the BCS-BE crossover for d-wave pairing in the 2-dimensional attractive Hubbard model. Contrary to their claims, we found that a non-pairing region does not exist in the density vs coupling phase diagram. The gap parameter at T=0, as obtained by solving analytically as well as numerically the BCS equations, is in fact finite for any non-zero density and coupling, even in the weak-coupling regime.Comment: 7 pages, 1 figur

Avaliação, seleção e recomendação de cutlivares de arroz de várzeas em Minas Gerais de 1997 a 2002.

A fim de tornar a orizicultura irrigada uma atividade mais atrativa, a EPAMIG desenvolve, em parceria com a EMBRAPA Arroz e Feijão, pesquisas de melhoramento genético de arroz de várzeas com o objetivo de obter cultivares superiores às já recomendadas, tanto em produtividade como em aceitação comercial

Developmental Toxicity of Endocrine Disrupters Bisphenol A and Vinclozolin in a Terrestrial Isopod

Studies of the effects of endocrine-disrupting compounds (EDCs) on invertebrates are still largely underrepresented. This work aims to fill this gap by assessing the effects of bisphenol A (BPA) and vinclozolin (Vz) on the terrestrial isopod Porcellio scaber (common rough woodlouse). Male adult and sexually undifferentiated juvenile woodlice were exposed to the toxicants. Effects on molting regime and growth were investigated independently for males and female woodlice after sexual differentiation. Both chemicals elicited developmental toxicity to P. scaber by causing overall decreased growth. Nevertheless, BPA induced molting, whereas Vz delayed it. Although the LC50 values for juvenile and adult survival were fairly similar, juvenile woodlice showed an increased chronic sensitivity to both chemicals, and female woodlice were most the sensitive to BPA. We recommend the use of adults, juveniles, female, and male woodlice, as well as a large range of toxicant concentrations, to provide valuable information regarding differential dose responses, effects, and threshold values for EDCs

Effect of the carbon source in the regulation of flocculation of Ale Brewer yeast strains

Instituto Politécnico do Porto. Fundo de Apoio à Investigação, Programa Plurianual de Unidades de I&D - CIEA/ISEP

Histological evaluation of the exposure to 3,4-dichloroaniline in the estuarine mysid Mesopodopsis slabberi, under experimental conditions

This work presents an experimental approach to test Mesopodopsis slabberi as a potential indicator of pollution. The toxic effects of 3,4-dichloroaniline (DCA) on the histology of this estuarine mysid were studied. After an acclimation period of two days, the mysids were exposed to different sublethal 3,4-DCA concentrations (0.10, 0.30, 0.50, 0.90, 1.00, 1.10, 1.20, 1.30 and 1.40 mg/L), for a period of 48 h. Each concentration had seven replicates, and one control. After the exposure period, organisms were sacrificed and submitted to a standard histological procedure with some modifications. Histological effects were analyzed in several tissues and damages were found in organisms exposed to concentrations higher then 0.30 mg/L. Muscular tissue, cuticular lens and gonads were clearly affected by 3,4-DCA, presenting accumulations of this toxic substance and lesions on the structures

Effects of triclosan on early development of Solea senegalensis: from biochemical to individual level

Harmful effects of triclosan (TCS) have been reported on several organisms; however, effects on early life stages of marine vertebrates are limited. Therefore, the objective of this work was to assess the effects of TCS during early development of the flatfish Solea senegalensis after initial characterization of cholinesterases (ChEs) and determination of selected biochemical markers baseline levels. Characterization of ChEs and determination of biochemical markers baseline levels of cholinergic activity, energy metabolism and oxidative stress were analysed in sole at 3 days after hatching (dah) and at the onset and end of metamorphosis. To assess TCS effects, fish were exposed during 96h to 30-500 μg L-1 TCS until 3 dah. Fish at 13 dah were exposed during 48h to 200-1,500 μg L-1 TCS and maintained until complete metamorphosis. Effects on survival, malformations, length, metamorphosis progression and biochemical markers were evaluated. The main ChE active form present in sole early life stages is acetylcholinesterase and baseline levels of oxidative stress and energy metabolism biomarkers changed according to fish developmental stage. Triclosan induced malformations (EC50 = 180 μg L-1 at 3 dah), decreased growth (95 μg L-1 at 3 dah; 548 μg L-1 at 24 dah) and affected metamorphosis progression (391 μg L-1 at 17 dah). Impairment of antioxidant system was observed, with TCS affecting catalase at the end of metamorphosis test, however, no oxidative damage on lipids was detected. Glutathione S-transferase was the most sensitive endpoint during early larval test (LOEC = 30 μg L-1). Exposure to TCS affected S. senegalensis at individual and sub-individual levels, both at early larval stage and during the critical period of metamorphosis.publishe