RESUMO
Even though Sugars Will Eventually be Exported Transporters (SWEETs) have been found in every sequenced plant genome, a comprehensive understanding of their functionality is lacking. In this study, we focused on the SWEET family of barley (Hordeum vulgare). A radiotracer assay revealed that expressing HvSWEET11b in African clawed frog (Xenopus laevis) oocytes facilitated the bidirectional transfer of not only just sucrose and glucose, but also cytokinin. Barley plants harboring a loss-of-function mutation of HvSWEET11b could not set viable grains, while the distribution of sucrose and cytokinin was altered in developing grains of plants in which the gene was knocked down. Sucrose allocation within transgenic grains was disrupted, which is consistent with the changes to the cytokinin gradient across grains, as visualized by magnetic resonance imaging and Fourier transform infrared spectroscopy microimaging. Decreasing HvSWEET11b expression in developing grains reduced overall grain size, sink strength, the number of endopolyploid endosperm cells, and the contents of starch and protein. The control exerted by HvSWEET11b over sugars and cytokinins likely predetermines their synergy, resulting in adjustments to the grain's biochemistry and transcriptome.
Assuntos
Citocininas , Hordeum , Citocininas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Hordeum/genética , Hordeum/metabolismo , Açúcares/metabolismo , Sacarose/metabolismoRESUMO
The initial free expansion of the embryo within a seed is at some point inhibited by its contact with the testa, resulting in its formation of folds and borders. Although less obvious, mechanical forces appear to trigger and accelerate seed maturation. However, the mechanistic basis for this effect remains unclear. Manipulation of the mechanical constraints affecting either the in vivo or in vitro growth of oilseed rape embryos was combined with analytical approaches, including magnetic resonance imaging and computer graphic reconstruction, immunolabelling, flow cytometry, transcriptomic, proteomic, lipidomic and metabolomic profiling. Our data implied that, in vivo, the imposition of mechanical restraints impeded the expansion of testa and endosperm, resulting in the embryo's deformation. An acceleration in embryonic development was implied by the cessation of cell proliferation and the stimulation of lipid and protein storage, characteristic of embryo maturation. The underlying molecular signature included elements of cell cycle control, reactive oxygen species metabolism and transcriptional reprogramming, along with allosteric control of glycolytic flux. Constricting the space allowed for the expansion of in vitro grown embryos induced a similar response. The conclusion is that the imposition of mechanical constraints over the growth of the developing oilseed rape embryo provides an important trigger for its maturation.
RESUMO
Maize (Zea mays) kernels are the largest cereal grains, and their endosperm is severely oxygen deficient during grain fill. The causes, dynamics, and mechanisms of acclimation to hypoxia are minimally understood. Here, we demonstrate that hypoxia develops in the small, growing endosperm, but not the nucellus, and becomes the standard state, regardless of diverse structural and genetic perturbations in modern maize (B73, popcorn, sweet corn), mutants (sweet4c, glossy6, waxy), and non-domesticated wild relatives (teosintes and Tripsacum species). We also uncovered an interconnected void space at the chalazal pericarp, providing superior oxygen supply to the placental tissues and basal endosperm transfer layer. Modeling indicated a very high diffusion resistance inside the endosperm, which, together with internal oxygen consumption, could generate steep oxygen gradients at the endosperm surface. Manipulation of oxygen supply induced reciprocal shifts in gene expression implicated in controlling mitochondrial functions (23.6 kDa Heat-Shock Protein, Voltage-Dependent Anion Channel 2) and multiple signaling pathways (core hypoxia genes, cyclic nucleotide metabolism, ethylene synthesis). Metabolite profiling revealed oxygen-dependent shifts in mitochondrial pathways, ascorbate metabolism, starch synthesis, and auxin degradation. Long-term elevated oxygen supply enhanced the rate of kernel development. Altogether, evidence here supports a mechanistic framework for the establishment of and acclimation to hypoxia in the maize endosperm.
Assuntos
Amido , Zea mays , Gravidez , Feminino , Humanos , Zea mays/metabolismo , Amido/metabolismo , Placenta/metabolismo , Endosperma/metabolismo , Oxigênio/metabolismo , Hipóxia/metabolismoRESUMO
Adventitious root (AR) formation is one of the most important developmental processes in vegetative propagation. Although genotypic differences in rose rooting ability are well known, the causal factors are not well understood. The rooting of two contrasting genotypes, 'Herzogin Friederike' and 'Mariatheresia', was compared following a multiscale approach. Using magnetic resonance imaging, we non-invasively monitored the inner structure of stem cuttings during initiation and progression of AR formation for the first time. Spatially resolved Fourier-transform infrared spectroscopy characterized the chemical composition of the tissues involved in AR formation. The results were validated through light microscopy and complemented by immunolabelling. The outcome demonstrated similarity of both genotypes in root primordia formation, which did not result in root protrusion through the shoot cortex in the difficult-to-root genotype 'Mariatheresia'. The biochemical composition of the contrasting genotypes highlighted main differences in cell wall-associated components. Further spectroscopic analysis of 15 contrasting rose genotypes confirmed the biochemical differences between easy- and difficult-to-root groups. Collectively, our data indicate that it is not the lack of root primordia limiting AR formation in these rose genotypes, but the firmness of the outer stem tissue and/or cell wall modifications that pose a mechanical barrier and prevent root extension and protrusion.
Assuntos
Genótipo , Imageamento por Ressonância Magnética , Raízes de Plantas , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/genética , Espectroscopia de Infravermelho com Transformada de Fourier , FenótipoRESUMO
Imaging has long supported our ability to understand the inner life of plants, their development, and response to a dynamic environment. While optical microscopy remains the core tool for imaging, a suite of novel technologies is now beginning to make a significant contribution to visualize plant metabolism. The purpose of this review was to provide the scientific community with an overview of current imaging methods, which rely variously on either nuclear magnetic resonance (NMR), mass spectrometry (MS) or infrared (IR) spectroscopy, and to present some examples of their application in order to illustrate their utility. In addition to providing a description of the basic principles underlying these technologies, the review discusses their various advantages and limitations, reveals the current state of the art, and suggests their potential application to experimental practice. Finally, a view is presented as to how the technologies will likely develop, how these developments may encourage the formulation of novel experimental strategies, and how the enormous potential of these technologies can contribute to progress in plant science.
Assuntos
Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética/métodos , Espectrometria de MassasRESUMO
Haemonchus contortus is a highly pathogenic and prevalent helminth that causes many deaths in sheep herds. Anthelmintics are usually employed to overcome this issue; however, they do not guarantee immediate and lasting efficacy because of the occurrence of drug-resistant parasites. Among substances that are used in scientific studies for parasitic control, essential oils are known to have different pharmacological properties. However, they demonstrate instability owing to several factors, and therefore, nanoemulsification is considered an alternative to control the instability and degradability of these compounds. The objective of this study was to evaluate the cytotoxicity of nanoemulsions containing essential oil of Eucalyptus globulus against the blood of healthy sheep and to verify their activity against the parasite H. contortus in sheep. The results presented adequate nanotechnological characteristics (diameter 72 nm, PDI 0.2, zeta -11 mV, and acidic pH) and adequate morphology. Further, the corona effect and cytotoxic profiles of the free oil and nanoemulsion against blood cells from healthy sheep were evaluated. The tests results did not present a toxicity profile. For evaluating efficacy, we observed an important anthelmintic action of the nanoemulsion containing oil in comparison to the free oil; the results demonstrate a potential role of the nanoemulsion in the inhibition of egg hatchability and the development of larvae L1 to L3 (infective stage). Based on these results, we developed an important and potential anthelmintic alternative for the control of the parasite H. contortus.
Assuntos
Anti-Helmínticos , Hemoncose , Haemonchus , Óleos Voláteis , Doenças dos Ovinos , Animais , Anti-Helmínticos/uso terapêutico , Anti-Helmínticos/toxicidade , Óleo de Eucalipto/farmacologia , Hemoncose/tratamento farmacológico , Hemoncose/parasitologia , Hemoncose/veterinária , Larva , Óleos Voláteis/química , Óleos Voláteis/toxicidade , Ovinos , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/parasitologiaRESUMO
Successful biotrophic plant pathogens can divert host nutrition toward infection sites. Here we describe how the protist Plasmodiophora brassicae establishes a long-term feeding relationship with its host by stimulating phloem differentiation and phloem-specific expression of sugar transporters within developing galls. Development of galls in infected Arabidopsis (Arabidopsis thaliana) plants is accompanied by stimulation of host BREVIS RADIX, COTYLEDON VASCULAR PATTERN, and OCTOPUS gene expression leading to an increase in phloem complexity. We characterized how the arrest of this developmental reprogramming influences both the host and the invading pathogen. Furthermore, we found that infection leads to phloem-specific accumulation of SUGARS WILL EVENTUALLY BE EXPORTED TRANSPORTERS11 and 12 facilitating local distribution of sugars toward the pathogen. Utilizing Fourier-transform infrared microspectroscopy to monitor spatial distribution of carbohydrates, we found that infection leads to the formation of a strong physiological sink at the site of infection. High resolution metabolic and structural imaging of sucrose distributions revealed that sweet11 sweet12 double mutants are impaired in sugar transport toward the pathogen, delaying disease progression. This work highlights the importance of precise regulation of sugar partitioning for plant-pathogen interactions and the dependence of P brassicae's performance on its capacity to induce a phloem sink at the feeding site.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Floema/citologia , Floema/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Doenças das Plantas , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Hypericin is a molecule of high pharmaceutical importance that is synthesized and stored in dark glands (DGs) of St. John's Wort (Hypericum perforatum). Understanding which genes are involved in dark gland development and hypericin biosynthesis is important for the development of new Hypericum extracts that are highly demanded for medical applications. We identified two transcription factors whose expression is strictly synchronized with the differentiation of DGs. We correlated the content of hypericin, pseudohypericin, endocrocin, skyrin glycosides and several flavonoids with gene expression and DG development to obtain a revised model for hypericin biosynthesis. Here, we report for the first time genotypes which are polymorphic for the presence/total absence (G+/G-) of DGs in their placental tissues (PTs). DG development was characterized in PTs using several microscopy techniques. Fourier transform infrared microscopy was established as a novel method to precisely locate polyaromatic compounds, such as hypericin, in plant tissues. In addition, we obtained transcriptome and metabolome profiles of unprecedented resolution in Hypericum. This study addresses for the first time the development of dark glands and identifies genes that constitute strong building blocks for the further elucidation of hypericin synthesis, its manipulation in plants, its engineering in microbial systems and its applications in medical research.
Assuntos
Hypericum/genética , Hypericum/metabolismo , Perileno/análogos & derivados , Antracenos , Flavonoides , Genes de Plantas , Metaboloma , Perileno/metabolismo , TranscriptomaRESUMO
Pseudomonas aeruginosa is a ubiquitous microorganism that commonly causes hospital-acquired infections, including pneumonia, bloodstream and urinary tract infections and it is well known for chronically colonising the respiratory tract of patients with cystic fibrosis, causing severe intermittent exacerbation of the condition. P. aeruginosa may appear in the free form cell but also grows in biofilm communities adhered to a surface. An alternative to conventional antimicrobial agents are nanoparticles that can act as carriers for antibiotics and other drugs. In this context, the study aimed to characterise and verify the anti-biofilm potential of GML Nanocapsules against P. aeruginosa. The nanocapsules showed a mean diameter of 190.7â¯nm, polydispersion index of 0.069, the zeta potential of -23.3â¯mV. The microdilution test showed a MIC of 62.5⯵g/mL to GML and 15.62⯵g/mL to GML Nanocapsules. The anti-biofilm experiments demonstrated the significant reduction of biomass, proteins, polysaccharide and viable P. aeruginosa in biofilm treated with GML Nanocapsules while the free GML did not cause an effect. The AFM images showed a decrease in a biofilm which received GML. The positive results suggest an alternative for the public health trouble related to infections associated with biofilm.
Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Lauratos/farmacologia , Monoglicerídeos/farmacologia , Nanocápsulas , Pseudomonas aeruginosa/efeitos dos fármacos , Tensoativos/farmacologia , Portadores de Fármacos , Testes de Sensibilidade MicrobianaRESUMO
The increase of microbial resistance generates the search for new substances with antimicrobial potential. The essential oil of Cymbopogon flexuosus (Lemongrass) stands out in the literature for its antimicrobial, insecticide and antioxidant properties, but it has high volatilization and low stability, and the nanoencapsulation of this oil could be an alternative to overcome these limitations. Thus, the objective of this study was to develop, for the first time, nanoemulsions containing the essential oil of C. flexuosus, through a method that does not use organic solvent and with temperature control to avoid the volatilization of the oil, characterize and evaluate of stability and the antimicrobial and antibiofilm activities of these nanoemulsions. Nanoemulsions presented adequate physicochemical characteristics (average size less than 200â¯nm, polydispersity index less than 0.3, negative zeta potential and acid pH) which were maintained during 90 days of storage, and the nanoencapsulation of the C. flexuosus oil enhanced its therapeutic efficacy against the microorganisms evaluated in this study compared to the free oil. These results are very promising because among the microorganisms that the nanoemulsion containing C. flexuosus was able to inhibit the formation of biofilm are the bacteria Pseudomonas aeruginosa and Staphylococcus aureus, which were recently listed by the World Health Organization as priority pathogens for development of new antibiotics.
Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Cymbopogon/química , Nanopartículas/química , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Antibacterianos/farmacologia , Antioxidantes , Estabilidade de Medicamentos , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Transmissão , Nanopartículas/ultraestrutura , Óleos Voláteis/química , Tamanho da Partícula , Óleos de Plantas/química , Óleos de Plantas/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , TemperaturaRESUMO
Quinine, a treatment used in chloroquine-resistant falciparum malaria, was loaded into poly(É-caprolactone) or Eudragit® RS100 nanocapsules using Curcuma oil as the oil-based core. Until now, the effect of cationic nanocapsules on malaria has not been reported. A 24 factorial design was adopted using, as independent variables, the concentration of Curcuma oil, presence of quinine, type of polymer, and aqueous surfactant. Diameter, zeta potential, and pH were the responses studied. The formulations were also evaluated for drug content, encapsulation efficiency, photostability, and antimalarial activity against Plasmodium berghei-infected mice. The type of polymer influenced all of the responses studied. Quinine-loaded Eudragit® RS100 (F13) and PCL nanocapsules (F9), both with polysorbate 80 coating, showed nanometric particle size, positive zeta potential, neutral pH, high drug content, and quinine photoprotection ability; thus, these nanocapsules were selected for in vivo tests. Both formulations showed lower levels of parasitemia from the beginning of the experiment (5.78 ± 3.60 and 4.76 ± 3.46% for F9 and F13, respectively) and highest survival mean time (15.3 ± 2.0 and 14.9 ± 5.6 days for F9 and F13, respectively). F9 and F13 showed significant survival curve compared to saline, thus demonstrating that nanoencapsulation improved bioefficacy of QN and co-encapsulated curcuminoids, regardless of the surface charge.
Assuntos
Antimaláricos/administração & dosagem , Curcuma , Malária/tratamento farmacológico , Óleos de Plantas/administração & dosagem , Quinina/administração & dosagem , Animais , Antimaláricos/uso terapêutico , Caproatos , Portadores de Fármacos , Excipientes , Lactonas , Camundongos , Nanocápsulas/química , Tamanho da Partícula , Óleos de Plantas/uso terapêutico , Polímeros/química , Ácidos Polimetacrílicos , Quinina/uso terapêuticoRESUMO
Candida species are the main responsible microorganisms for causing fungal infections worldwide, and Candida albicans is most frequently associated with infectious processes. Pseudomonas aeruginosa is a gram-negative bacterium commonly found in immunocompromised patients. The infection persistence caused by these microorganisms is often related to antimicrobial resistance and biofilm formation. In this context, the objective of the present study was to prepare and characterize nanoemulsions containing Eucalyptus globulus oil and to verify its antimicrobial and antibiofilm activities against P. aeruginosa and Candida spp. The nanoemulsions had a size of approximately 76 nm, a polydispersity index of 0.22, a zeta potential of - 9,42 mV and a pH of approximately 5.0. The E. globulus oil was characterized by gas chromatography, being possible to observe its main components, such as 1-8-Cineol (75.8%), p- Cymene (7.5%), α-Pinene (7.4%) and Limonene (6.4%). The antimicrobial activity of the nanoemulsion was determined from the macrodilution tests and the cell viability curve, where the minimum fungicidal concentration of 0.7 mg/mL for C. albicans and 1.4 mg/mL for C. tropicalis and C. glabrata were obtained. However, the nanoemulsions did not present antimicrobial activity against P. aeruginosa, since it contains only 5% of the oil, being ineffective for this microorganism. The nanoencapsulated oil action against the formed biofilm was evaluated by atomic force microscopy and calcofluor staining, and the nanoemulsion was more efficient for two of the three Candida species when compared to free oil.
Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Candida/efeitos dos fármacos , Eucalyptus/química , Nanopartículas/química , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Anti-Infecciosos/química , Benzenossulfonatos , Monoterpenos Bicíclicos , Biofilmes/crescimento & desenvolvimento , Cicloexanóis , Cicloexenos , Cimenos , Eucaliptol , Concentração de Íons de Hidrogênio , Limoneno , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Monoterpenos , Nanotecnologia , Óleos Voláteis/administração & dosagem , Tamanho da Partícula , Propriedades de Superfície , TerpenosRESUMO
Bacterial biofilms are involved in various medical infections and for this reason it is of great importance understanding adhesion mechanisms of involved microorganisms is essential to develop new strategies of prevention and control. Different approaches have been used for preventing biofilm related infections in health care settings, such as use of surface coatings agents in medical implants. In this context, is necessary to explore new compounds with anti-biofilm activity. Thus, this study evaluated for the first time the action of A22 against biofilms of Pseudomonas aeruginosa PAO1 strain and multi-resistant clinical isolates on biotic and abiotic surfaces. A22 acts as inhibitor of the MreB protein of the bacterial cell wall, causing the rods to change shape to the coccoid form. In this work, A22 at subinhibitory concentrations was able to prevent biofilm formation, and atomic force microscopy images showed that A22 was highly effective in inhibiting adhesion on polyethylene surfaces. Pseudomonas aeruginosa PAO1 exhibited a strong ability to adhere to HeLa cells, and A22 inhibited the aggregation after 4 h of exposure. Swarming and twitching motilities were significantly altered by A22 at subinhibitory concentrations. Thus, by changing the shape of the bacterial cell, many properties can be affected, such as motility, surface adhesion and biofilm formation. This work presents A22 as a promising novel antibacterial or surface coating agent of medical materials.
Assuntos
Antibacterianos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Tioureia/análogos & derivados , Proteínas de Bactérias/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Parede Celular , Células HeLa , Humanos , Testes de Sensibilidade Microbiana , Microscopia de Força Atômica , Polietileno , Tioureia/antagonistas & inibidores , Fatores de TempoRESUMO
Microbial biofilms represent a challenge in the treatment of infections, due to the low efficacy of the antimicrobials. This study evaluated the antimicrobial effect of nanoparticles of Melaleuca alternifolia (TTO) in dental biofilm. Thirty-eight volunteers used an oral device in situ in situ including four bovine enamel specimens for 07 days. From the fifth day four solutions were applied randomly for each specimen: Physiological Saline Solution (0.85% NaCl) (C+), Chlorhexidine 0.12% (CHX), M. alternifolia oil 0.3% (TTO), and a nanoparticle solution of 0.3% M. alternifolia oil (NPTTO). The nanoparticles of TTO were characterized for pH, IPD, medium size, zeta potential and Transmission Electron Microscopy. Antimicrobial activity was evaluated by viable microorganisms count and the structure of the biofilm by atomic force microscopy. The NPTTO presented pH 6.4, particle diameter of 197.9 ± 1 nm, polydispersion index of 0.242 ± 0.005, zeta potential of -7.12 mV and ±0:27 spherical shape. The C+ resulted in 100% of bacterial vitality, while CHX, TTO and NPTTO showed 34.2%, 51.4% and 25.8%, respectively. The AFM images showed biofilms with an average roughness of 350 nm for C+, 275 nm for CHX, 500 nm for TTO and 100 nm for NPTTO. The NPTTO demonstrated excellent antimicrobial activity in the biofilm formed in situ and will possibly be used in future for the treatment/prevention of oral biofilms.
Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Melaleuca/química , Nanopartículas/química , Exsudatos de Plantas/farmacologia , Adulto , Animais , Bactérias/efeitos dos fármacos , Aderência Bacteriana/efeitos dos fármacos , Brasil , Bovinos , Clorexidina/farmacologia , Contagem de Colônia Microbiana , Esmalte Dentário/microbiologia , Placa Dentária/tratamento farmacológico , Placa Dentária/microbiologia , Placa Dentária/prevenção & controle , Feminino , Humanos , Concentração de Íons de Hidrogênio , Masculino , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Tamanho da Partícula , Projetos Piloto , Cloreto de Sódio/farmacologia , Óleo de Melaleuca/farmacologia , Fatores de Tempo , Adulto JovemRESUMO
Infections due to microbial biofilm formation on the surface of catheters and other medical devices are constantly reported as a major cause of morbidity and mortality in patients admitted to hospitals. Furthermore, sessile cells are more resistant to phagocytosis and most antimicrobial, which complicates the treatment of such infections. Researches aimed at new antimicrobial originating mainly from plants have increased in recent years and the development of new strategies for their release is critical in combating the formation of biofilms. Geranium oil (GO) has proven antimicrobial activity. Because of this, the aim of this study was to develop nanoemulsions containing this oil (NEG) and evaluate its activity after the biofilm formation of Candida albicans, Candida tropicalis, Candida glabrata, and Candida krusei in hospital medical supplies. For quantification of the biofilm, crystal violet, total protein, and ATP-bioluminescence assays were used. The results revealed that GO and NEG showed lower MIC for C. albicans and C. tropicalis. The biofilms formed by different species of Candida on the surfaces of polyethylene and polyurethane were quantified. GO and NEG significantly inhibited the formation of biofilms in all species tested on the surfaces of polyethylene. However, NEG antibiofilm has had better activity than GO for C. albicans, C. tropicalis and C. glabrata, according to the surface potential analysis by atomic force microscopy (AFM). The analysis of the biofilm formation on the polyethylene surface by ATP-bioluminescence and CFU showed similar results. In both methods the formation of biofilm in the catheter occurred in greater quantity for C. albicans and C. tropicalis. GO did not significantly inhibit the formation of biofilms only in C. krusei, although NEG significantly increased this activity GO in all species tested when compared to the control training biofilm. The following study shows that the development of NEG may become an effective alternative to reduce the adhesion of microorganisms and prevent infections resulting from the use of some hospital medical materials.
Assuntos
Antifúngicos/farmacologia , Biofilmes/efeitos dos fármacos , Candida/efeitos dos fármacos , Equipamentos e Provisões/microbiologia , Pelargonium/química , Extratos Vegetais/farmacologia , Antifúngicos/isolamento & purificação , Candida/fisiologia , Emulsões/farmacologia , Hospitais , Testes de Sensibilidade Microbiana , Extratos Vegetais/isolamento & purificaçãoRESUMO
PURPOSE: To evaluate the effect of different concentrations of hydrofluoric acid (HF) on the contact angle and the resin bond strength durability to feldspathic ceramic. MATERIALS AND METHODS: To evaluate the contact angles of distilled water on etched feldspathic ceramic, 25 specimens (12×10×2.4 mm) of VitaBlocks Mark II were used, divided into 5 groups (n=5): one unconditioned control (UC) group with no ceramic surface treatment, and 4 other groups that were etched for 60 s with different concentrations of HF: 1% (HF1), 3% (HF3), 5% (HF5) and 10% (HF10). The bond testing utilized 40 ceramic blocks (12×10×4 mm) that were fabricated and subjected to the same surface treatments as previously mentioned (excluding the control). The etched surfaces were silanized and resin cement was applied. After 24 h, the blocks were sectioned to produce bar specimens that were divided into two groups, non-aged (immediate testing) and aged (storage for 230 days+12,000 thermocycles at 5°C and 55°C), and subjected to microtensile testing (µTBS). Micromorphogical analysis of the treated surfaces was also performed (atomic force and scanning electron microscopy). One-way ANOVA and Tukey's tests were applied for data analysis. RESULTS: UC had the highest contact angle (61.4°), whereas HF10 showed the lowest contact angle (17.5°). In non-aged conditions, different acids promoted statistically similar bond strengths (14.2 to 15.7 MPa) (p>0.05); in terms of bond durability, only the bond strength of the HF1 group presented a statistically significant decrease comparing before and after aging (14.5 to 10.2 MPa). CONCLUSION: When etched with 3%, 5%, or 10% hydrofluoric acid, the ceramic tested showed stable resin adhesion after long-term aging.
Assuntos
Condicionamento Ácido do Dente/métodos , Silicatos de Alumínio/química , Cerâmica/química , Colagem Dentária , Ácido Fluorídrico/química , Compostos de Potássio/química , Cimentos de Resina/química , Bis-Fenol A-Glicidil Metacrilato/química , Porcelana Dentária/química , Humanos , Teste de Materiais , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Distribuição Aleatória , Silanos/química , Estresse Mecânico , Propriedades de Superfície , Temperatura , Resistência à Tração , Fatores de Tempo , MolhabilidadeRESUMO
The objective of this work was to prepare and characterize liposomes containing co-encapsulated ascorbic acid (AA) and ascorbyl palmitate (AP), as well as to evaluate their stability, cytotoxicity, antioxidant, and antimicrobial activity. Through the pre-formulation studies, it was possible to improve the formulation, as leaving it more stable and with a greater antioxidant activity, resulting in a formulation designated LIP-AAP, with 161 nm vesicle size, 0.215 polydispersity index, -31.7 mV zeta potential, and pH of 3.34. Encapsulation efficiencies were 37% for AA and 79% for AP, and the content was 1 mg/mL for each compound. The optimized liposomes demonstrated stability under refrigeration for 60 days, significant antioxidant activity (31.4 µMol of TE/mL), and non-toxicity, but no antimicrobial effects against bacteria and fungi were observed. These findings confirm that the co-encapsulated liposomes are potent, stable antioxidants that maintain their physical and chemical properties under optimal storage conditions.
RESUMO
Ferulic acid (FA) is a phenolic compound that has antioxidant, anti-inflammatory and anticarcinogenic properties besides presenting cytoprotective activity. It has limited oral bioavailability what is a challenge to its therapeutic application. In this way, this investigation aimed to develop FA-loaded nanocapsule suspensions (NC-FA) prepared with ethylcellulose and evaluate their in vitro release profile, mucoadhesion and irritation potential; scavenging capacity, cytotoxicity, cytoprotection and genoprotection against hydrogen peroxide-induced damage in hMNC (human Mononucleated Cells) culture. The nanocapsules presented physicochemical characteristics compatible with colloidal systems (NC-FA: 112 ± 3 nm; NC-B (without FA): 107 ± 3 nm; PdI < 0.2; Span<2.0 and negative zeta potential). In addition, the nanoparticulate system promoted the FA controlled release, increasing the half-life twice through the in vitro dialysis method. NC-FA and NC-B were able to interact with mucin, which is an indicative of mucoadhesive properties and the association of FA with nanocapsules showed decreased irritation by HET-CAM method. Besides, the NC-FA did not present cytotoxicity in hMNC and improved the ATBS radical scavenging capacity. Besides, it prevented, treated and reversed oxidative conditions in a H2O2-induced model in hMNC. Thus, this nanocarrier formulation is promising to perform more preclinical investigations focusing on diseases involving oxidative mechanisms.
Assuntos
Antioxidantes/administração & dosagem , Ácidos Cumáricos/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Nanocápsulas/química , Animais , Antioxidantes/farmacocinética , Antioxidantes/farmacologia , Células Cultivadas , Celulose/análogos & derivados , Embrião de Galinha , Ácidos Cumáricos/farmacocinética , Ácidos Cumáricos/farmacologia , Humanos , Peróxido de Hidrogênio/toxicidade , Irritantes , Linfócitos , Mucinas , Nanocápsulas/efeitos adversosRESUMO
The objective of this work was to produce and characterise nanoemulsions containing tucumã extract and to evaluate the performance of the nanostructure and the free compound regarding antitumor activity, cytotoxicity, and oxidative metabolism in NB4/APL cells. The nanoemulsions showed adequate physicochemical characteristics (average size approx. 200 nm, polydispersity index less than 0.3, negative zeta potential and acid pH) maintained stable up to 90 days of storage in refrigeration condition. The nanoformulations did not present protein corona formation. Blank nanoemulsion treatments showed moderate toxicity. Furthermore, the nanoemulsion loaded with extract showed better antileukemic results than the free extract. However, nanoemulsions can be promising carriers of natural compounds, emphasising their biological properties and constituting alternatives in treating diseases.
Assuntos
Arecaceae , Nanoestruturas , Antioxidantes/química , Emulsões/química , Nanoestruturas/químicaRESUMO
The aim of this study was to evaluate the toxicity of tucumã oil nanocapsules from the Amazon region in silver catfish, Rhamdia quelen. Fish were exposed to water treated with different concentrations of tucumã nanocapsules, white, solubilized oil and surfactant vehicles. After three days of exposure, fish were euthanized and liver, gills and brain removed for analysis of the dichlorofluorescein, nitric oxide and PicoGreen® assays. Plasma was collected for assay of hepatic transaminases. The nanocapsules had a diameter of 221 ± 1.27 nm, confirmed by atomic force microscopy. The oil nanocapsules were not toxic to this species of fish, but white nanocapsules and surfactant increased the levels of reactive oxygen species. Thus, nanocapsules are promising for the transport of tucumã oil. In view of the anti-inflammatory properties of this oil, it is possible to envisage its application in skin diseases for example, since they present essentially inflammatory conditions.HighlightsThe most abundant carotenoid in tucumã oil was all-trans-beta-carotene.Nanocapsules are good carriers for tucumã oil.Tucumã oil nanocapsules does nothas toxicity effect in catfish.