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1.
Environ Sci Pollut Res Int ; 26(22): 22529-22550, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161543

RESUMO

Widespread application of silver nanoparticles (AgNPs), due to their antibacterial and antifungal properties, increases their release into the environment and potential detrimental impact on living organisms. Plants may serve as a potential pathway for AgNPs bioaccumulation and a route into the food chain, hence investigation of AgNP phytotoxic effects are of particular importance. Since proteins are directly involved in stress response, studies of their abundance changes can help elucidate the mechanism of the AgNP-mediated phytotoxicity. In this study, we investigated proteomic changes in tobacco (Nicotiana tabacum) exposed to AgNPs and ionic silver (AgNO3). A high overlap of differently abundant proteins was found in root after exposure to both treatments, while in leaf, almost a half of the proteins exhibited different abundance level between treatments, indicating tissue-specific responses. Majority of the identified proteins were down-regulated in both tissues after exposure to either AgNPs or AgNO3; in roots, the most affected proteins were those involved in response to abiotic and biotic stimuli and oxidative stress, while in leaf, both treatments had the most prominent effect on photosynthesis-related proteins. However, since AgNPs induced higher suppression of protein abundance than AgNO3, we conclude that AgNP effects can, at least partially, be attributed to nanoparticle form.


Assuntos
Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Tabaco/fisiologia , Íons , Estresse Oxidativo/efeitos dos fármacos , Folhas de Planta/metabolismo , Proteoma/metabolismo , Proteômica , Nitrato de Prata/toxicidade , Tabaco/metabolismo
2.
Chemosphere ; 229: 86-93, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31078035

RESUMO

In the environment co-contamination of several toxicants commonly occurs. However, toxicological studies usually are focused on only one toxicant. The aim of this study was to investigate toxicity of silver nanoparticles (AgNP) and mycotoxin fumonisin B1 (FB1) and their possible interactions as well as to explore tentative mechanism of their toxic effect. Duckweed (Lemna minor L.) was treated with AgNP or FB1 (at concentrations 0.5 and 1.0 mg L-1) or with their combination at same concentrations for 3 days. Both AgNP and FB1, applied individually significantly affected levels of certain nutrients, reduced growth rate and the levels of photosynthetic pigments though AgNP at a much greater extent compared to FB1. Furthermore, AgNP induced ROS generation, lipid peroxidation and increase of antioxidative enzymes activities, while FB1 induced changes only in the activities of antioxidative enzymes. Those results implicate that phytotoxicity of both AgNP and FB1 can be associated with imbalance of mineral and cell redox status. However, toxic actions of AgNp singly applied were more pronounced. Combined treatment with AgNP and FB1 produced higher degree of changes in all parameters than corresponding concentrations of AgNP or FB1 alone implying their additive effects. Additionally, higher level of FB1 found in medium, and higher level of intracellular Ag following combined treatment indicates interaction of two toxicants at the transport level/uptake in the cell which resulted in higher accumulation of Ag in duckweed cells. The latter in turn exerted higher toxicity to duckweed compared to single treatment of AgNP.


Assuntos
Araceae/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Fumonisinas/toxicidade , Nanopartículas Metálicas/toxicidade , Prata/química , Prata/toxicidade , Animais , Antioxidantes/metabolismo , Araceae/metabolismo , Interações de Medicamentos , Poluentes Ambientais/metabolismo , Fumonisinas/metabolismo , Nutrientes/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Prata/metabolismo
3.
Evolution ; 73(1): 15-27, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30411346

RESUMO

Some of the most varied colors in the natural world are created by iridescent nanostructures in bird feathers, formed by layers of melanin-containing melanosomes. The morphology of melanosomes in iridescent feathers is known to vary, but the extent of this diversity, and when it evolved, is unknown. We use scanning electron microscopy to quantify the diversity of melanosome morphology in iridescent feathers from 97 extant bird species, covering 11 orders. In addition, we assess melanosome morphology in two Eocene birds, which are the stem lineages of groups that respectively exhibit hollow and flat melanosomes today. We find that iridescent feathers contain the most varied melanosome morphologies of all types of bird coloration sampled to date. Using our extended dataset, we predict iridescence in an early Eocene trogon (cf. Primotrogon) but not in the early Eocene swift Scaniacypselus, and neither exhibit the derived melanosome morphologies seen in their modern relatives. Our findings confirm that iridescence is a labile trait that has evolved convergently in several lineages extending down to paravian theropods. The dataset provides a framework to detect iridescence with more confidence in fossil taxa based on melanosome morphology.

4.
Methods Mol Biol ; 1815: 351-370, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29981135

RESUMO

Separation of plant proteins by means of electrophoretic techniques is quite challenging since different compounds typical for plant cells can interfere and/or reduce the effectiveness of the protein isolation. This is particularly problematic for two-dimensional electrophoresis (2-DE). Therefore, it is important to optimize protein extraction and to establish a robust protocol for 2-DE and downstream processing, primarily mass spectrometry (MS) analysis. Here we give a detailed protocol for protein extraction using phenol method, 2-DE, and MALDI-MS analysis.


Assuntos
Eletroforese em Gel Bidimensional/métodos , Fenóis/química , Proteômica/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Algoritmos , Sequência de Aminoácidos , Automação , Eletroforese em Gel de Poliacrilamida , Focalização Isoelétrica
5.
J Phycol ; 54(2): 275-298, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29419886

RESUMO

The diatom genus Entomoneis is known from the benthos and plankton of marine, brackish, and freshwaters. Entomoneis includes diatoms with a bilobate keel elevated above the valve surface, a sigmoid canal raphe, and numerous girdle bands. Owing mostly to the scarcity of molecular data for a diverse set of species, the phylogeny of Entomoneis has not been investigated in depth. The few previous studies that included Entomoneis were focused on broader questions and the available data were from a small number of either unidentified Entomoneis or well-known species (e.g., E. paludosa). Since the first description of new species combining both molecular and morphological characters (E. tenera), we have continued to cultivate and investigate Entomoneis in the plankton of the Adriatic Sea. Combined multigene phylogeny (SSU rDNA sequences, rbcL, and psbC genes) and morphological observations (LM, SEM and TEM) revealed six new Entomoneis species supported by phylogenetic and morphological data: E. pusilla, E. gracilis, E. vilicicii, E. infula, E. adriatica, and E. umbratica. The most important morphological features for species delineation were cell shape, the degree and mode of torsion, valve apices, the appearance and structure of the transition between keel and valve body, the ultrastructure and the shape of the girdle bands, and the arrangement and density of perforations along the valve and valvocopulae. Our results highlight the underappreciated diversity of Entomoneis and call for a more in-depth morphological and molecular investigation of this genus especially in planktonic habitats.


Assuntos
Diatomáceas/classificação , Diatomáceas/citologia , Proteínas de Algas/análise , Croácia , DNA de Algas/análise , DNA Ribossômico/análise , Diatomáceas/genética , Diatomáceas/ultraestrutura , Mar Mediterrâneo , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Filogenia
6.
Ecotoxicol Environ Saf ; 137: 18-28, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27894021

RESUMO

Silver nanoparticles (AgNPs) are the dominating nanomaterial in consumer products due to their well-known antibacterial and antifungal properties. To enhance their properties, different surface coatings may be used, which affect physico-chemical properties of AgNPs. Due to their wide application, there has been concern about possible environmental and health consequences. Since plants play a significant role in accumulation and biodistribution of many environmentally released substances, they are also very likely to be influenced by AgNPs. In this study we investigated the toxicity of AgNO3 and three types of laboratory-synthesized AgNPs with different surface coatings [citrate, polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB)] on Allium cepa roots. Ionic form of Ag was confirmed to be more toxic than any of the AgNPs applied. All tested AgNPs caused oxidative stress and exhibited toxicity only when applied in higher concentrations. The highest toxicity was recorded for AgNPs-CTAB, which resulted with increased Ag uptake in the roots, consequently leading to strong reduction of the root growth and oxidative damage. The weakest impact was found for AgNPs-citrate, much bigger, negatively charged NPs, which also aggregated to larger particles. Therefore, we can conclude that the toxicity of AgNPs is directly correlated with their size, overall surface charge and/or surface coating.


Assuntos
Antibacterianos/toxicidade , Dano ao DNA , Nanopartículas Metálicas/toxicidade , Cebolas/efeitos dos fármacos , Prata/toxicidade , Antibacterianos/metabolismo , Antioxidantes/metabolismo , Ácido Cítrico/química , Relação Dose-Resposta a Droga , Íons/toxicidade , Peroxidação de Lipídeos/efeitos dos fármacos , Cebolas/genética , Cebolas/metabolismo , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Tamanho da Partícula , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Povidona/química , Prata/metabolismo , Nitrato de Prata/toxicidade
7.
Int J Radiat Biol ; 92(8): 475-82, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27258329

RESUMO

PURPOSE: Ultraviolet (UV) radiation-induced apoptosis enabled us to study the mechanism of DNA damage and to investigate how cells avoid consequences of damaged DNA. Cells with extensive DNA damage activate extrinsic and intrinsic pathways of apoptosis. The extrinsic pathway is coupled to a FAS-associated protein with death domain (FADD), an adaptor protein molecule necessary for mediating apoptotic signals through the cell. MATERIALS AND METHODS: Viability and apoptosis of wild-type and FADD-deficient mouse embryonic fibroblasts were investigated 1, 3, 24 and 48 h after exposure to three doses (50, 75 and 300 J/m(2)) of UVC radiation. Morphological changes were observed using DNA binding dyes (Hoechst and propidium iodide) while biochemical changes were monitored using immunodetection of the poly (ADP-ribose) polymerase (PARP) protein cleavage and caspase-3 activity assay. RESULTS: Results showed that the difference in cell death response between wild-type and FADD-deficient cells depended on dose and incubation time after exposure to UVC radiation. FADD-deficient cells are more sensitive to UVC radiation. Even though FADD-deficient cells lack an adapter protein of apoptotic extrinsic pathway, higher doses of UVC triggered their apoptotic response, while wild-type cells die mainly due to necrosis. A different pattern of caspase 3 activity and PARP cleavage was observed 24 h after radiation between two cell lines confirming higher apoptotic response in FADD-deficient cells. CONCLUSIONS: Wild-type cells can execute apoptosis via both, the mitochondrial and the receptor-mediated pathway whereas FADD-deficient cells can only activate the intrinsic pathway. There is a difference in UVC radiation response between two cell lines indicating the role of FADD in the selection of cell death modality.


Assuntos
Apoptose/efeitos da radiação , Dano ao DNA/fisiologia , Proteína de Domínio de Morte Associada a Fas/metabolismo , Fibroblastos/fisiologia , Fibroblastos/efeitos da radiação , Raios Ultravioleta , Animais , Apoptose/genética , Linhagem Celular , Sobrevivência Celular/genética , Sobrevivência Celular/efeitos da radiação , Relação Dose-Resposta à Radiação , Fibroblastos/citologia , Camundongos , Camundongos Knockout , Doses de Radiação
8.
PLoS One ; 8(12): e82548, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24340039

RESUMO

The chloroplast is the most prominent and metabolically active plastid in photosynthetic plants. Chloroplasts differentiate from proplastids in the plant meristem. Plant plastids contain multiple copies of a small circular genome. The numbers of chloroplasts per mesophyll cell and of plastid genome copies are affected by developmental stage and environmental signals. We compared chloroplast structure, gene expression and genome copy number in Arabidopsis seedlings germinated and grown under optimal conditions to those in seedlings germinated and grown in the presence of NaCl. Chloroplasts of the NaCl-grown seedlings were impaired, with less developed thylakoid and granum membranes than control seedlings. In addition, chloroplasts of salt-grown Arabidopsis seedlings accumulated more starch grains than those in the respective control plants. Steady-state transcript levels of chloroplast-encoded genes and of nuclear genes encoding chloroplast proteins were reduced in salt-grown seedlings. This reduction did not result from a global decrease in gene expression, since the expression of other nuclear genes was induced or not affected. Average cellular chloroplast genome copy number was reduced in salt-grown seedlings, suggesting that the reduction in steady-state transcript levels of chloroplast-encoded genes might result from a decrease in template DNA.


Assuntos
Arabidopsis/metabolismo , Cloroplastos/metabolismo , Dosagem de Genes , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Plântula/metabolismo , Transcrição Genética/efeitos dos fármacos , Arabidopsis/genética , Cloroplastos/genética , Plântula/genética , Cloreto de Sódio
9.
Arh Hig Rada Toksikol ; 63(3): 321-35, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23152382

RESUMO

The effects of 10 µmol L-1 and 15 µmol L-1 cadmium (Cd), a nonessential toxic element and 25 µmol L-1 and 50 µmol L-1 zinc (Zn), an essential micronutrient, on proteins and glycoproteins of Nicotiana tabacum L. seedlings and plants were investigated after exposure to each metal alone or to their combinations. Changes in only few polypeptides related to heavy metal treatments were observed in tobacco seedlings and leaves of adult plants, while the greatest change in total soluble protein pattern was observed in plant roots. Differences between control and treated tobacco tissues were more pronounced in the glycoprotein pattern, which was analysed by application of different lectins. The majority of the detected glycoproteins in leaves and roots of adult plants can be considered as a result of enhanced glycosylation due to heavy metal stress. The difference in glycoproteins between Cd and Zn application on tobacco seedlings and adult plants could not be determined since enhanced glycosylation was noticed after treatment with either metal alone or in combination. Therefore, it can be concluded that both metals induced N- and Oglycosylation as a result of changed environmental conditions.


Assuntos
Cádmio/farmacocinética , Cádmio/toxicidade , Plântula/metabolismo , Tabaco/efeitos dos fármacos , Tabaco/metabolismo , Zinco/farmacologia , Zinco/farmacocinética , Misturas Complexas , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glicosilação , Humanos , Estresse Oxidativo/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Proteínas de Plantas/efeitos dos fármacos , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Plântula/efeitos dos fármacos , Tabaco/genética
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