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1.
Food Chem ; 307: 125543, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31634760

RESUMO

Phosphate fertilisation affects the growth, development and quality of Tartary buckwheat. In this study, the effect of different phosphorus levels, including 0, 15, 75, and 135 kg/ha (non-, low-, medium-, and high-phosphorus levels, respectively), on the characteristics of starch from Tartary buckwheat were investigated in 2015 and 2017. With increased phosphorus level, the median diameter of starch granules and the apparent amylose content initially decreased and then increased. All starch samples showed the features of A-type X-ray diffraction patterns. Starches under medium-phosphorus treatment showed higher relative crystallinity than those under non-phosphorus treatment, as well as the highest solubility, gelatinisation enthalpy and transmittance among all starches. Starches under low-phosphorus treatment exhibited higher pasting properties than those under non-phosphorus treatment. This research revealed that phosphorus treatments and year significantly affected the physicochemical properties of Tartary buckwheat starch, and can provide information for the applications of starch in the food and non-food industries.


Assuntos
Fagopyrum/química , Fertilizantes , Fosfatos/farmacologia , Amido/química , Amilose/química , Fenômenos Químicos , Fagopyrum/efeitos dos fármacos , Solubilidade
2.
Int J Food Microbiol ; 312: 108362, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31669764

RESUMO

Stuck and sluggish fermentations are among the main problems in winemaking industry leading to important economic losses. Several factors have been described as causes of stuck and sluggish fermentations, being exposure to extreme temperatures barely studied. The objective of this study was to identify thermal conditions leading to stuck and sluggish fermentations, focusing on the impact of an abrupt and transient decrease/increase of temperature on fermentation performance and yeast viability/vitality. Different strains of Saccharomyces cerevisiae, SBB11, T73, and PDM were evaluated in synthetic grape must fermentations. Cold shocks (9 °C and 1.5 °C for 16 h) carried out on different days during the fermentation process were unable to alter fermentation performance. Conversely, shock temperatures higher than 32 °C, applied in early stages of the process, lead to sluggish fermentation showing a delay directly related to the temperature increase. Fermentation delay was associated with a decrease in cell vitality. The impact of the heat shock on fermentation performance was different depending on the strain evaluated and nitrogen supplementation (with or without diammonium phosphate addition). None of the conditions evaluated produced a stuck fermentation and importantly, in all cases must nutrition improved fermentation performance after a heat shock.


Assuntos
Temperatura Baixa , Fermentação/fisiologia , Temperatura Alta , Saccharomyces cerevisiae/metabolismo , Resposta ao Choque Frio/fisiologia , Resposta ao Choque Térmico/fisiologia , Fosfatos/farmacologia , Vitis/metabolismo , Vinho/análise
3.
Mater Sci Eng C Mater Biol Appl ; 104: 109933, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499966

RESUMO

Osteoporotic bone represents - particularly in case of fractures - difficult conditions for its regeneration. In the present study, the focus was put on a degradable bone substitute material of gelatin-modified calcium and strontium phosphates facing the special demands of osteoporotic bone. The release of strontium ions from the material ought to stimulate osteoblastogenesis either direct by ion release or indirect after material resorption by increased presence and activity of osteoclasts, which subsequently stimulate osteoblasts. A new porous material was produced from calcium phosphate, strontium phosphate and a mixed phase of calcium/strontium phosphate precipitated in presence of gelatin. Initially, ion release was analyzed in standard­calcium containing (2.0 mM) and low-calcium (0.4 mM) minimum essential medium. The cultivation of human peripheral blood mononuclear cells next to the material led to formation of osteoclast-like cells, able to migrate, fuse, and differentiate. Especially, the mixed gelatin-modified calcium/strontium phosphate allowed osteoclastogenesis as proven morphologically and by real-time quantitative polymerase chain reaction (RT-qPCR). It was precisely this material that led to the best osteoblastic reaction of human bone marrow stromal cells cultured on the material. The investigations of the bone substitute material indicate active involvement in the balance of cells of the bone morphogenetic unit.


Assuntos
Materiais Biocompatíveis/farmacologia , Fosfatos de Cálcio/farmacologia , Gelatina/farmacologia , Osteoblastos/efeitos dos fármacos , Osteoclastos/efeitos dos fármacos , Fosfatos/farmacologia , Estrôncio/farmacologia , Animais , Contagem de Células , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Minerais/metabolismo , Monócitos/citologia , Monócitos/efeitos dos fármacos , Osteoblastos/citologia , Osteoclastos/citologia , Osteogênese/efeitos dos fármacos , Suínos
4.
Int J Food Microbiol ; 309: 108334, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31520893

RESUMO

In this study, we show that phosphate decreases the spore heat resistance by accelerating the rate of loss of cations from spores. Heat resistance of spores of Geobacillus stearothermophilus A1, D1, P3 and ATCC 12980 were determined in distilled water containing varying concentrations (0.1, 1 and 2% w/v) of di­sodium phosphate. The average decimal reduction times (D value) for strains A1, D1, P3 and ATCC 12980 in distilled water were 5.8, 6.8, 5.7 and 9 min at 110 °C respectively. On the addition of 0.1, 1 and 2% w/v of di­sodium phosphate, the average D110 values of all the strains in distilled water were lowered by 50, 61 and 70% respectively. Addition of 0.05% w/v of Na-EDTA to distilled water resulted in lowering of the average D110 value of all the strains by 55%. Heat resistance of spores of A1, D1, P3 and ATCC 12980 was found to be associated with the Dipicolinic Acid (DPA) content whose concentrations were 0.25, 0.30, 0.27 and 1.6 pg per spore respectively. Analysis by atomic absorption spectroscopy revealed that the phosphate present in the heating medium causes excess release of calcium from spores with 2% w/v phosphate being highly effective, thus confirming the chelating effect of phosphate. This study provides insight into the heat resistance and the increased heat sensitivity of spores of G. stearothermophilus A1, D1 and P3 in the presence of phosphate, which can be used in the design of Cleaning in Place (CIP) systems involving phosphate based cleaning agents to combat biofilms and spores in the dairy industry.


Assuntos
Desinfecção/métodos , Geobacillus stearothermophilus/crescimento & desenvolvimento , Fosfatos/farmacologia , Ácidos Picolínicos/análise , Esporos Bacterianos/efeitos dos fármacos , Indústria de Laticínios/métodos , Calefação/métodos , Temperatura Alta
5.
Mater Sci Eng C Mater Biol Appl ; 104: 109929, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500017

RESUMO

The clinical application of composites seeks to exploit the mechanical and chemical properties of materials which make up the composite, and in researching polymer composites for biomedical applications the aim is usually to enhance the bioactivity of the polymer, while maintaining the mechanical properties. To that end, in this study medical grade Poly(L-lactic) acid (PLLA) has been reinforced with short phosphate-based glass fibers (PGF). The materials were initially mixed by melting PLLA granules with the short fibers, before being extruded to form a homogenous filament, which was pelletized and used as feedstock for compression moulding. As made the composite materials had a bending strength of 51 MPa ±â€¯5, and over the course of eight weeks in PBS the average strength of the composite material was in the range 20-50 MPa. Human mesenchymal stromal cells were cultured on the surfaces of scaffolds, and the metabolic activity, alkaline phosphatase production and mineralization monitored over a three week period. The short fiber filler made no significant difference to cell proliferation or differentiation, but had a clear and immediate osteoinductive effect, promoting mineralization by cells at the material surface. It is concluded that the PLLA/PGF composite material offers a material with both the mechanical and biological properties for potential application to bone implants and fixation, particularly where an osteoinductive effect would be valuable.


Assuntos
Calcificação Fisiológica/efeitos dos fármacos , Vidro/química , Fosfatos/farmacologia , Poliésteres/farmacologia , Bioensaio , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Íons , Osteogênese/efeitos dos fármacos , Espectroscopia de Prótons por Ressonância Magnética , Difração de Raios X
6.
Braz Oral Res ; 33: e058, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31432925

RESUMO

Cementum is the mineralized tissue covering the tooth root that functions in tooth attachment and post-eruptive adjustment of tooth position. It has been reported to be highly similar to bone in several respects but remains poorly understood in terms of development and regeneration. Here, we investigate whether cementocytes, the residing cells in cellular cementum, have the potential to be protagonist in cementum homeostasis, responding to endocrine signals and directing local cementum metabolism. Cells from healthy erupted human teeth were isolated using sequential collagenase/EDTA digestions, and maintained in standard cell culture conditions. A cementocyte-like cell line was cloned (HCY-23, for human cementocyte clone 23), which presented a cementocyte compatible gene expression signature, including the expression of dentin matrix protein 1 ( DMP1 ), sclerostin ( SOST ), and E11/gp38/podoplanin ( E11 ). In contrast, these cells did not express the odontoblast/dentin marker dentin sialoprotein ( DSPP ). HCY-23 cells produced mineral-like nodules in vitro under differentiation conditions, and were highly responsive to inorganic phosphate (Pi). Within the limits of the present study, it can be concluded that cementocytes are phosphate-responsive cells, and have the potential do play a key role in periodontal homeostasis and regeneration.


Assuntos
Técnicas de Cultura de Células/métodos , Cemento Dentário/citologia , Adolescente , Adulto , Análise de Variância , Proteínas Morfogenéticas Ósseas/análise , Proteínas Morfogenéticas Ósseas/genética , Linhagem Celular , Cemento Dentário/metabolismo , Proteínas da Matriz Extracelular/análise , Proteínas da Matriz Extracelular/genética , Feminino , Imunofluorescência , Expressão Gênica , Marcadores Genéticos/genética , Humanos , Masculino , Glicoproteínas de Membrana/análise , Glicoproteínas de Membrana/genética , Dente Molar/citologia , Fosfatos/farmacologia , Fosfoproteínas/análise , Fosfoproteínas/genética , Sialoglicoproteínas/análise , Sialoglicoproteínas/genética , Fatores de Tempo , Adulto Jovem
7.
Int J Biol Macromol ; 136: 253-265, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31170491

RESUMO

Ribokinase (RK) is an ATP dependent sugar kinase that enables the entry of ribose in the metabolism. Leishmania accumulates ribose into the cytosol through hydrolysis of nucleosides and by transport from the extracellular environment. Activation by RK is critical to mobilize the ribose into the metabolism of Leishmania. To understand the catalytic role, the crystal structure of RK (LdRK) from L. donovani was determined in the apo and complex forms with several nucleotides (ATP, AMPPCP and ADP) in the presence of Na+ ion. The dual insertion of five amino acid stretches makes LdRK structurally unique from other reported structures of RKs. The structure of LdRK-ATP provided the basis for positioning of γ-phosphate of ATP by conserved -GAGD- motif. Liganded and unliganded structures of LdRK exists in similar conformation, which suggests binding of nucleotides does not make any significant conformational changes in nucleotide-bound structures. Substitution of a conserved asparagine with phenylalanine in ribose binding pocket differentiates the LdRK from other RKs. Glycerol molecule bound in the substrate binding pocket mimics the enzyme-substrate interactions but in turn, hampers the binding of ribose to LdRK. Comparative structural analysis revealed the flexibility of γ-phosphate, which adopts multiple conformations in the absence of divalent metal ion and ribose. Similar to other RKs, LdRK is also dependent on monovalent as well as divalent cations for its catalytic activity.


Assuntos
Leishmania donovani/enzimologia , Fosfotransferases (Aceptor do Grupo Álcool)/química , Sequência de Aminoácidos , Sítios de Ligação , Cristalografia por Raios X , Modelos Moleculares , Nucleotídeos/metabolismo , Fosfatos/farmacologia , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Conformação Proteica
8.
Environ Sci Pollut Res Int ; 26(20): 20475-20484, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31102230

RESUMO

The ambiguous mechanism that selenite seems to be absorbed by roots via phosphorus (P) and silicon (Si) transporters signifies P and Si may affect selenite uptake. However, the role of P and Si in phloem-mediated selenium (Se) transport within plant tissue is unknown. Therefore, in this work, tomato (Solanum lycopersicum L.) seedlings were exposed to selenite under different hydroponic conditions firstly. And then, split-root experiments were conducted. Results showed that Se uptake decreased as external pH increased. At pH 8, more selenite in the form of SeO32- was assimilated under P-deficient conditions than under P-normal conditions. Silicate inhibited Se uptake only at pH 3 (27.5% H2SeO3 +72.5% HSeO3-). The results of split-root experiments showed that Se concentrations in seedlings increased under heterogeneously high P or Si. Selenium transport from shoots to roots immersed in solution without selenite was also enhanced. This study illustrated that the affinity of tomato roots to assimilate selenite species followed the order of H2SeO3 >HSeO3- >SeO32-. H2SeO3 was absorbed into roots via Si transporters, whereas HSeO3- and a portion of SeO32- were absorbed via low- and high-affinity P transporters, respectively. In addition, heterogeneously high P or Si concentrations in environmental media could enhance phloem-mediated Se redistribution.


Assuntos
Lycopersicon esculentum/efeitos dos fármacos , Floema/metabolismo , Fosfatos/farmacologia , Ácido Selenioso/farmacocinética , Silicatos/farmacologia , Transporte Biológico/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Hidroponia , Lycopersicon esculentum/metabolismo , Floema/efeitos dos fármacos , Fósforo/farmacologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Selênio/metabolismo , Selênio/farmacocinética
9.
J Sci Food Agric ; 99(12): 5526-5532, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31102411

RESUMO

BACKGROUND: Trisodium phosphate (TSP), generally recognized as safe (GRAS), could control postharvest diseases and maintain fruit quality. However, changes of fruit quality and sucrose metabolism in harvested jujube after TSP treatment remain largely unknown. In the current study, jujube fruit (cv. sanxing) was used to study the effects of TSP on storage quality and sucrose metabolism during storage at 20 ± 2 °C with 40-50% relative humidity (RH). RESULTS: The results showed that 0.5 g L-1 TSP treatment reduced weight loss and reduced sugar content, suppressed the reduction of fruit firmness, maintained ascorbic acid (AsA) content and inhibited respiratory rate of jujube fruit. In addition, TSP treatment also reduced acid invertase (AI) and neutral invertase (NI) activities in sucrose metabolism in jujube fruit. Sucrose synthase-cleavage (SS-c), sucrose synthase-synthesis (SS-s) and sucrose phosphate synthase (SPS) activities were also suppressed by TSP treatment. CONCLUSION: Treatment with TSP could effectively reduce enzymes activities in sucrose metabolism and maintain storage quality of jujube fruit during storage. © 2019 Society of Chemical Industry.


Assuntos
Conservantes de Alimentos/farmacologia , Frutas/química , Fosfatos/farmacologia , Ziziphus/efeitos dos fármacos , Conservação de Alimentos , Armazenamento de Alimentos , Frutas/efeitos dos fármacos , Glucosiltransferases/metabolismo , Proteínas de Plantas/metabolismo , Controle de Qualidade , Sacarose/análise , Ziziphus/química
10.
Cell Physiol Biochem ; 52(4): 838-849, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30946558

RESUMO

BACKGROUND/AIMS: Phosphate (Pi) homeostasis is controlled by the intestine and kidneys whose capacities to transport Pi are under endocrine control. Several studies point to intestinal absorption as a therapeutic target to modulate Pi homeostasis. The small intestine is responsible for almost all Pi absorption in the gut, a process involving Na+-dependent and independent mechanisms. Three Na+-dependent Pi cotransporters have been described in the gastrointestinal tract: NaPi-IIb (a SLC34 member) and Pit-1 and Pit-2 (SLC20 transporters). We recently analysed the acute hormonal and renal response to intragastric (i.g) and intravenous (i.v) Pi-loading. This study demonstrated that the kidney quickly adapts to Pi-loading, with changes manifesting earlier in the i.v than i.g intervention. The aim of this work was to extend the previous studies in order to investigate the acute adaptation of intestinal transport of Pi and expression of intestinal Na+/Pi-cotransporters in response to acute Pi-loading. METHODS: Duodenal and jejunal mucosa was collected 40 minutes and/or 4 hours after administration (i.g and i.v) of either NaCl or Pi to anaesthetized rats. Uptakes of Pi and protein expression of Na+/Pi cotransporters were measured in brush border membrane vesicles (BBMV); the cotransporters' mRNA abundance was quantified by real-time PCR in total RNA extracted from whole mucosa. RESULTS: Pi-loading did not modify transport of Pi in duodenal and jejunal BBMV 4 hours after treatment. Administration of Pi did not alter either the intestinal expression of NaPi-IIb and Pit-2 mRNAs, whereas Pit-1 mRNA expression was only regulated (diminished) in duodenum collected 4 hours after i.g Pi-loading. NaPi-IIb protein expression was decreased in duodenum 4 hours upon i.v Pi infusion, whereas the duodenal and jejunal abundance of the cotransporter was unaffected by i.g administration of Pi. CONCLUSION: Together, these data suggest that the intestine responds acutely to Pi-loading, though this response seems slower than the renal adaptation.


Assuntos
Regulação para Baixo/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Fosfatos/farmacologia , Administração Intravenosa , Animais , Glucose/metabolismo , Mucosa Intestinal/citologia , Mucosa Intestinal/metabolismo , Masculino , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIb/metabolismo , Fator de Transcrição Pit-1/genética , Fator de Transcrição Pit-1/metabolismo
11.
Environ Pollut ; 250: 676-685, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31035150

RESUMO

Phytostabilization of sulfidic PbZn tailing landscapes may be one of interim options of tailings management, but which is limited by acute phytotoxicity of heavy metals in the tailings. The present study aimed to investigate the effectiveness of soluble phosphate (i.e., K2HPO4) in immobilizing soluble Pb, Cd and Zn and lowering their acute phytotoxicity. The addition of soluble phosphate improved the growth of native plants Acacia chisholmii and survival rate of A. ligulata, where the latter exhibited 100% survival rate. This was in contrast to effects of conventional organic amendment in the tailings on metal solubility (e.g., elevated metal levels in porewater) and plant survival (e.g., only 42%). Organic amendment with mulch did not lower the levels of water-soluble Cd, Pb and Zn and their concentrations in plant tissues after 56 days of plant growth in the treatment. In contrast, the tailings amended with K2HPO4 significantly decreased metal concentrations in the porewater and plant tissues by about 80-92% and 56-88%, respectively. The metal immobilization by phosphate was due to the formation of insoluble or sparingly soluble metal (Pb, Cd and Zn)-phosphate minerals in the tailings with circumneutral pH conditions, as revealed by using X-ray diffraction and scanning electron microanalyses. The reduced metal concentrations in roots and shoots of Acacia species after direct root contact with the K2HPO4 amended tailings suggested that metals (i.e., Pb, Cd and Zn) were effectively immobilized by the phosphate treatment of the tailings. These findings indicate that addition of high dosage of soluble phosphate may provide a low cost option to treat sulfidic PbZn tailings for rapid phytostabilization of the tailings surface, as an interim option to manage environmental risks of sulfidic PbZn tailings.


Assuntos
Acacia/efeitos dos fármacos , Cádmio/toxicidade , Chumbo/toxicidade , Fosfatos/farmacologia , Poluentes do Solo/toxicidade , Zinco/toxicidade , Acacia/crescimento & desenvolvimento , Cádmio/análise , Chumbo/análise , Mineração , Modelos Teóricos , Poluentes do Solo/análise , Sulfetos , Zinco/análise
12.
Chemosphere ; 228: 117-127, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31026632

RESUMO

Algae accumulate and metabolize arsenic (As) and facilitate cycling and speciation of As in seawater. The laboratory-controlled macroalgal cultures were exposed to different molar ratios of As(V) and phosphate (P) in seawater for evaluating the uptake and metabolism of As, as a function of As(V) detoxification through biotransformation. Chlorophyll fluorescence of algal species was not significantly affected by the culture conditions (p > 0.05). Addition of 10 µM P positively reduce As stress, but different As(V)/P ratios significantly affect the growth rate (p < 0.05). Algae readily accumulated As(V) after the inoculation, transformed intracellularly, and released gradually into the medium along the incubation period, depending on As(V)/P molar ratios. Reduction and methylation were the leading processes of As(V) metabolism by Pyropia yezoensis, whereas Sargassum patens showed only the reduction. Sargassum horneri reduced As(V) under low level (0.1 µM), but both reduction and methylation were observed under a high level (1 µM). At the end of incubation, 0.17, 0.15, 0.1 µM of reduced metabolite (As[III]) were recorded from 1 µM of As(V)/P containing cultures of Sargassum horneri, Sargassum patens, and Pyropia yezoensis, respectively. On the other hand, 0.024 and 0.28 µM of methylated metabolite (DMAA[V]) were detected under the same culture conditions from Sargassum horneri and Pyropia yezoensis, respectively. The results also indicated that P in medium inhibits the intracellular uptake of As(V) and subsequent extrusion of biotransformed metabolites into the medium. These findings can help to understand the metabolic diversity of macroalgae species on As biogeochemistry in the marine environment.


Assuntos
Arsênico/metabolismo , Biotransformação , Inativação Metabólica , Alga Marinha/metabolismo , Metilação , Fosfatos/metabolismo , Fosfatos/farmacologia , Sargassum , Água do Mar
13.
Exp Parasitol ; 199: 59-66, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30825498

RESUMO

Fasciolosis is a zoonotic world widely distributed disease caused by the liver fluke Fasciola hepatica, which affects animals and occasionally humans. On the other hand, natural iron oxide particles like magnetite are commonly found in soils where they participate in a wide range of environmental processes like organic matter decomposition, the adsorption of ions and molecules, and chemical reactions that involve the participation of soil living microorganisms. Since Fasciola eggs become soil components after being released with the infected animal faeces, this study focused on the characterization of the natural interaction between natural sub-micrometric magnetite particles and F. hepatica eggs. Our results indicate that particle binding to the F. hepatica egg depends on the particle size and it is also related to the exposed surface area since any condition that favors particle agglomeration leads to the reduction of the particle-eggshell binding intensity. Interestingly, this binding was avoided when proteins or phosphate were incorporated to the incubation solution, but not after formaldehyde fixation of eggs. Finally, when eggs were exposed to an external magnet after being incubated with magnetite particles, they were attracted to it without particles being detached, indicating a strong type of bonding between them. Therefore, the results presented here give new insights in order to improve the possibility of harvesting F. hepatica eggs by using magnetic materials.


Assuntos
Fasciola hepatica/metabolismo , Óxido Ferroso-Férrico/metabolismo , Animais , Ensaio de Desvio de Mobilidade Eletroforética , Fasciolíase/parasitologia , Fasciolíase/veterinária , Fezes/parasitologia , Fixadores/farmacologia , Formaldeído/farmacologia , Concentração de Íons de Hidrogênio , Nanopartículas de Magnetita/ultraestrutura , Microscopia Eletrônica de Transmissão , Distribuição Normal , Óvulo/metabolismo , Tamanho da Partícula , Peroxidase/análise , Fosfatos/farmacologia , Proteínas/farmacologia , Ovinos , Doenças dos Ovinos/parasitologia , Solo/química , Solo/parasitologia , Espectrometria por Raios X
14.
Braz Oral Res ; 33: e010, 2019 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-30892409

RESUMO

This in situ study aimed to evaluate the antibacterial and anti-demineralization effects of an experimental orthodontic adhesive containing triazine and niobium phosphate bioglass (TAT) around brackets bonded to enamel surfaces. Sixteen volunteers were selected to use intra-oral devices with six metallic brackets bonded to enamel blocks. The experimental orthodontic adhesives were composed by 75% BisGMA and 25% TEGDMA containing 0% TAT and 20% TAT. Transbond XT adhesive (TXT) was used as a control group. Ten volunteers, mean age of 29 years, were included in the study. The six blocks of each volunteer were detached from the appliance after 7 and 14 days to evaluate mineral loss and bacterial growth including total bacteria, total Streptococci, Streptococci mutans, and Lactobacilli. Statistical analysis was performed using GLM model - univariate analysis of variance for microhardness and 2-way ANOVA for bacterial growth (p<0.05). The 20% TAT adhesive caused no difference between distances from bracket and the sound zone at 10-µm deep after 7 and 14 days. After 14 days, higher mineral loss was shown around brackets at 10- to 30-µm deep for TXT and 0% TAT adhesives compared to 20% TAT. S. mutans growth was inhibited by 20% TAT adhesive at 14 days. Adhesive with 20% TAT showed lower S. mutans and total Streptococci growth than 0% TAT and TXT adhesives. The findings of this study show that the adhesive incorporated by triazine and niobium phosphate bioglass had an anti-demineralization effect while inhibiting S. mutans and total Streptococci growth. The use of this product may inhibit mineral loss of enamel, preventing the formation of white spot lesions.


Assuntos
Antibacterianos/farmacologia , Cimentos Dentários/farmacologia , Lactobacillus/efeitos dos fármacos , Nióbio/farmacologia , Óxidos/farmacologia , Fosfatos/farmacologia , Streptococcus/efeitos dos fármacos , Desmineralização do Dente/prevenção & controle , Adulto , Antibacterianos/química , Cerâmica/química , Cerâmica/farmacologia , Cimentos Dentários/química , Método Duplo-Cego , Feminino , Humanos , Masculino , Adulto Jovem
15.
Braz Oral Res ; 33: e016, 2019 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-30892411

RESUMO

To synthesize Nano eggshell-titanium-dioxide (EB@TiO2) biocomposite and to evaluate its effectiveness in occluding opened dentine tubules. EB@TiO2 was synthesized and characterized using X-ray diffraction (XRD), and Transmission Electron Microscope (TEM). Sixteen simulated bovine dentine discs were prepared and randomly assigned into four groups according to the following treatment (n = 4): Group 1: No treatment; Group 2: eggshell powder; Group 3: EB@TiO2; Group 4: Sensodyne. These were then agitated in a solution of 1g powder and 40mL water for 3hours. Thereafter, each dentine discs from the respective groups were post-treated for 5 min with 2wt% citric acid to test their acid resistant characteristics. Scanning Electron Microscope (SEM) was used to observe the effectiveness of occluded dentine pre-and post-treatment. The cytotoxicity of the synthesized EB@TiO2 was tested using NIH 3T3 assay. ANOVA was used to evaluate the mean values of the occluded area ratio and the data of MTS assay. This was followed by a multi-comparison test with Bonferroni correction (α = .05). The XRD confirmed that EB@TiO2 was successfully modified through ball-milling. The TEM revealed the presence of both spherical and irregular particle shape powders. The SEM result showed that EB@TiO2 could effectively occlude open dentine tubules. Equally, the result demonstrated that EB@TiO2 exhibited the highest acid resistant stability post-treatment. NIH 3T3 assay identified that EB@TiO2 had little effect on the NIH 3T3 cell line even at the highest concentration of 100µg/ml. This study suggests that the application of EB@TiO2 effectively occluded dentine tubules and the occlusion showed a high acid resistant stability.


Assuntos
Dessensibilizantes Dentinários/farmacologia , Permeabilidade da Dentina/efeitos dos fármacos , Sensibilidade da Dentina/terapia , Casca de Ovo/química , Fluoretos/farmacologia , Nanocompostos/química , Nitratos/farmacologia , Fosfatos/farmacologia , Titânio/química , Animais , Bovinos , Combinação de Medicamentos , Casca de Ovo/ultraestrutura , Camundongos , Microscopia Eletrônica de Varredura , Células NIH 3T3 , Nanocompostos/análise , Nanocompostos/uso terapêutico , Titânio/análise , Titânio/farmacologia , Remineralização Dentária
16.
Mater Sci Eng C Mater Biol Appl ; 98: 1145-1158, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30812998

RESUMO

3D powder printing is a versatile method for the fabrication of individual bone implants and was used for the processing of in vivo degradable ceramic scaffolds based on ammonium magnesium phosphate hexahydrate (struvite). In this study, synergetic effects could be achieved by the substitution of magnesium phosphate cements with strontium carbonate. This substitution resulted in 8.2 wt%, 16.4 wt%, and 24.6 wt% Sr2+ doped scaffolds, with a 1.9-3.1 times increased radiopacity compared to pure struvite. The maximal compressive strength of (16.1 ±â€¯1.1) MPa found for strontium substituted magnesium phosphate was in the range of cancelleous bone, which makes these 3D printed structures suitable for medical application in low-load-bearing bone areas. In an ion release study over a course of 18 days, the release of strontium, magnesium, calcium, and phosphate ions from scaffolds was analyzed by means of inductively coupled plasma mass spectrometry. Independent of the scaffold composition the Mg2+ concentrations (83-499 mg/l) continuously increased in the cell media. The Sr2+ release varied between 4.3 µg/day and 15.1 µg/day per g scaffold, corresponding to a Sr2+ concentration in media between 1.14 mg/l and 7.24 mg/l. Moreover, decreasing calcium and phosphate concentrations indicated the precipitation of an amorphous calcium phosphate phase. The superior osteogenic properties of strontium substituted magnesium phosphate, e.g. the increase of osteoblast activity and cell number and the simultaneous suppression of osteoclast differentiation could be verified in vitro by means of WST-assay, TRAP-staining, and SEM imaging.


Assuntos
Carbonatos/química , Carbonatos/farmacologia , Compostos de Magnésio/química , Compostos de Magnésio/farmacologia , Osteogênese/efeitos dos fármacos , Fosfatos/química , Fosfatos/farmacologia , Pós/química , Estrôncio/química , Estrôncio/farmacologia , Materiais Biocompatíveis/química , Osso e Ossos/efeitos dos fármacos , Cálcio/química , Fosfatos de Cálcio/química , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Cerâmica/química , Força Compressiva/efeitos dos fármacos , Humanos , Osteoblastos/efeitos dos fármacos , Impressão Tridimensional
17.
Chemosphere ; 222: 705-713, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30738313

RESUMO

Freshwater and marine organisms are capable of metabolizing arsenic (As) efficiently and regulating the As biogeochemical cycles. In this study, Undaria pinnatifida was exposed to As(V) (0, 0.1, and 1 µM) and phosphate (P; 1 and 10 µM) in seawater under laboratory-controlled conditions for up to seven days to analyze As biotransformation. The growth rates and chlorophyll fluorescence of the alga were unaffected by As stress, and statistically insignificant differences were observed among the cultures (p > 0.05). As(V) was readily accumulated by this macroalga through phosphate transporters, transformed intracellularly, and excreted into the medium, depending on the As(V) to P molar ratios. The concentration of As(V) and biotransformed species As(III) and DMAA(V) varied significantly in the algal cultures on the basis of the exposure period (p < 0.05). The concentration of As(III) was initially higher but decreased with the incubation period, whereas the concentration of DMAA(V) increased gradually. At the end of the incubation, 0.04 and 0.32 µM DMAA(V) were recorded in the media containing 0.1 and 1 µM As(V) with a constant 1.0 µM P, respectively. The results also indicated that the cellular uptake of As(V) and subsequent release of DMAA(V) were inhibited by P in the medium. The biotransformation was consistent with the As(V) detoxification mechanism based on reduction and methylation, which was enhanced by the lower As(V) to P molar ratios. These findings can be helpful in understanding the contribution of macroalgae to As biogeochemistry in marine environments and the potential risks of As dietary intake.


Assuntos
Arsênico/metabolismo , Undaria/metabolismo , Biotransformação , Inativação Metabólica , Metilação , Fosfatos/farmacologia , Água do Mar , Alga Marinha/metabolismo
18.
Proc Natl Acad Sci U S A ; 116(11): 4855-4860, 2019 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-30796184

RESUMO

Synthetic, resorbable scaffolds for bone regeneration have potential to transform the clinical standard of care. Here, we demonstrate that functional graphenic materials (FGMs) could serve as an osteoinductive scaffold: recruiting native cells to the site of injury and promoting differentiation into bone cells. By invoking a Lewis acid-catalyzed Arbuzov reaction, we are able to functionalize graphene oxide (GO) to produce phosphate graphenes (PGs) with unprecedented control of functional group density, mechanical properties, and counterion identity. In aqueous environments, PGs release inducerons, including Ca2+ and PO4 3- Calcium phosphate graphene (CaPG) intrinsically induces osteogenesis in vitro and in the presence of bone marrow stromal cells (BMSCs), can induce ectopic bone formation in vivo. Additionally, an FGM can be made by noncovalently loading GO with the growth factor recombinant human bone morphogenetic protein 2 (rhBMP-2), producing a scaffold that induces ectopic bone formation with or without BMSCs. The FGMs reported here are intrinsically inductive scaffolds with significant potential to revolutionize the regeneration of bone.


Assuntos
Regeneração Óssea/efeitos dos fármacos , Grafite/farmacologia , Células-Tronco Mesenquimais/citologia , Osseointegração/efeitos dos fármacos , Fosfatos/farmacologia , Tecidos Suporte/química , Animais , Proteína Morfogenética Óssea 2/farmacologia , Adesão Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Grafite/síntese química , Grafite/química , Humanos , Células-Tronco Mesenquimais/efeitos dos fármacos , Camundongos , Células NIH 3T3 , Osteogênese/efeitos dos fármacos , Fosfatos/síntese química , Fosfatos/química , Células RAW 264.7 , Proteínas Recombinantes/farmacologia , Fator de Crescimento Transformador beta/farmacologia
19.
Chem Res Toxicol ; 32(3): 456-466, 2019 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-30746940

RESUMO

Reactive nitrogen species (RNS) are produced during infection and inflammation, and the effects of these agents on proteins, DNA, and lipids are well recognized. In contrast, the effects of RNS damaged metabolites are less appreciated. 5-Amino-3-ß-(d-ribofuranosyl)-3 H-imidazo-[4,5- d][1,3]oxazine-7-one (oxanosine) and its nucleotides are products of guanosine nitrosation. Here we demonstrate that oxanosine monophosphate (OxMP) is a potent reversible competitive inhibitor of IMPDH. The value of Ki varies from 50 to 340 nM among IMPDHs from five different organisms. UV spectroscopy and X-ray crystallography indicate that OxMP forms a ring-opened covalent adduct with the active site Cys (E-OxMP*). Unlike the covalent intermediate of the normal catalytic reaction, E-OxMP* does not hydrolyze, but instead recyclizes to OxMP. IMPDH inhibitors block proliferation and can induce apoptosis, so the inhibition of IMPDH by OxMP presents another potential mechanism for RNS toxicity.


Assuntos
Inibidores Enzimáticos/farmacologia , IMP Desidrogenase/antagonistas & inibidores , Fosfatos/farmacologia , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , IMP Desidrogenase/isolamento & purificação , IMP Desidrogenase/metabolismo , Estrutura Molecular , Fosfatos/síntese química , Fosfatos/química , Ribonucleosídeos/síntese química , Ribonucleosídeos/química , Ribonucleosídeos/farmacologia
20.
Anal Chim Acta ; 1055: 98-105, 2019 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-30782376

RESUMO

Carboxylic acids have been efficiently used to activate H2O2 to form even more potent oxidant-peroxy acids through enzyme-catalyzed processes. By employing acetic acid as the activator, herein we report for the first time that cofactor-free DNA displays unexpected activity in H2O2-mediated oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) under mild conditions. A series of 10-nt oligonucleotides were rationally designed with various combinations of double nucleotides including TG, AG, CG, TA and AC respectively, which demonstrates that the catalytic performance of DNA is highly dependent upon the sequence composition, strand length and continuous nucleotides. Inspired by phosphate-induced inhibition effects on the formation of peracetic acid, an ultrasensitive assay was well-established for monitoring alkaline phosphatase (ALP) on the basis of double terminal-phosphorylated G-rich oligonucleotides. Phosphorylated DNA not only serves as the substrate for ALP-catalyzed hydrolysis, but also acts as the enzyme-like catalyst for signal amplification. Quantitative determination of ALP is realized in a linear range from 0.05 to 15 mU/mL, resulting in the limit of detection of 0.01 mU/mL. The rapid and reliable test also has great potential in analyzing serum samples for practical disease diagnosis.


Assuntos
Fosfatase Alcalina/metabolismo , Biocatálise , DNA/metabolismo , Ensaios Enzimáticos/métodos , Acetatos/farmacologia , Fosfatase Alcalina/antagonistas & inibidores , Fosfatase Alcalina/sangue , Benzidinas/química , Humanos , Peróxido de Hidrogênio/química , Hidrólise , Fosfatos/farmacologia
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