Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 45
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Artigo em Inglês | MEDLINE | ID: mdl-32052333

RESUMO

The internal critical concentration represented by the critical body residue (CBR) is an ideal indicator for reflecting the toxicity of a chemical. Although some authors have realized that the CBR50 can be calculated from the LC50 via the bioconcentration factor (BCF), the effects of exposure time and exposure concentration on the relationship between the LC50 and CBR50 have not been investigated to date. In this paper, the LC50 and CBR50 of ortho-dinitrobenzene in zebrafish were experimentally determined and their relationship was investigated. The results showed that ortho-dinitrobenzene exhibited excess toxicity and cannot completely be identified as a reactive compound based on toxic ratio. Comparison of the measured CBR50 and the CBR50 calculated from the LC50 via the BCF showed that there was a 0.46 log unit difference. Investigation of the relationship between the concentration in fish calculated by the toxicokinetic model and exposure time showed that the bio-uptake of fish was fast and reached a steady state in the toxicity test, indicating that the difference in CBR50 values could not be attributed to the different exposure times used in toxicity and BCF assays. On the other hand, investigation of the measured bioconcentration ratio (BCR) showed that the BCR (or BCFapp) decreased with increasing exposure concentration. Compared with the CBR50 calculated from the LC50 via the BCF, the CBR50 calculated from the LC50 via the BCFapp is close to the measured CBR50, suggesting that the difference in CBR50 values is attributed to the different exposure concentrations used in the BCF and toxicity assays.

2.
Sci Total Environ ; 715: 136816, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-32014765

RESUMO

The ozonation-based advanced oxidation process is a promising treatment technology for wastewater with micropollutants. The second-order reaction rate constant (kO3) of ozone (O3) with organic compounds is an important index for estimating removal efficiency of organic pollutants in engineered treatment; however, the experimental kO3 values are currently only available for hundreds of chemicals. In this study, two quantitative-structure activity relationship (QSAR) models were developed to predict kO3 of various organic chemicals with multiple linear regression (MLR) and support vector machine (SVM) methods. The built QSAR models cover a large dataset (136 chemicals) and more structurally diverse chemicals as compared to the existing models. The MLR model possesses satisfactory goodness-of-fit (R2tr = 0.734), robustness (Q2LOO = 0.700, Q2BOOT = 0.772) and predictive ability (R2ext = 0.797, Q2ext = 0.794), and the SVM model also has good fitness (R2tr = 0.862) and predictability (R2ext = 0.782, Q2ext = 0.775). The applicability domain of the models has been extended and includes chemicals (especially some emerging pollutants) that are rarely covered in many previous models. The underlying molecular structural factors influencing ozonation are revealed. The energy of the highest occupied molecular orbital (EHOMO) and the phenol/enol/carboxyl OH group (O-057) are the two most important molecular structural factors governing the reactivity of organic compounds with ozone. The developed models can serve as a prescreening tool for the removal prediction of organic pollutants by ozone.

3.
Artigo em Inglês | MEDLINE | ID: mdl-31916172

RESUMO

Risk assessment of pollutants to humans and ecosystems requires much toxicological data. However, experimental testing of compounds expends a large number of animals and is criticized for ethical reasons. The in silico method is playing an important role in filling the data gap. In this paper, the acute toxicity data of 1221 chemicals to Vibrio fischeri were collected. The global models obtained showed that there was a poor relationship between the toxicity data and the descriptors calculated based on linear and nonlinear regression analysis. This is due to the fact that the studied compounds contain not only non-reactive compounds but also reactive and specifically acting compounds with different modes of action (MOAs). MOAs are fundamental for the development of mechanistically based QSAR models and toxicity prediction. To investigate MOAs and develop MOA-based prediction models, the compounds were classified into baseline, less inert, reactive, and specifically acting compounds based on the modified Verhaar's classification scheme. Satisfactory models were established by multivariate linear regression (MLR) and support vector machine (SVM) analysis not only for baseline and less inert chemicals, but also for reactive and specifically acting compounds. Compared with linear models obtained by the MLR method, the nonlinear models obtained by the SVM method had better performance. The cross validation proved that all of the models were robust except for those for reactive chemicals with nN (number of nitrogen atoms) = 0 and n(C=O) (number of carbonyl groups) > 0 (Q2ext < 0.5). The application domains and outliers are discussed for those MOA-based models. The models developed in this paper are significantly helpful not only because the application domains for baseline and less inert compounds have been expended, but also the toxicity of reactive and specifically acting compounds can be successfully predicted. This work will promote understanding of toxic mechanisms and toxicity prediction for the chemicals with structural diversity, especially for reactive and specifically acting compounds.

4.
Chemosphere ; 243: 125345, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31739254

RESUMO

Acetochlor is a high-volume herbicide used on a global scale and toxicity assessments are needed to define its potential for adverse effects in wildlife and humans. This study was conducted to determine the effects of acetochlor on human liver carcinoma cells (HepG2), a cell model widely used to assess the potential for chemical hepatotoxicity. Experiments were conducted at concentrations ranging 0-800 µM acetochlor over a 12 to 48h period to quantify underlying mechanisms of toxicity. Our data indicate that acetochlor suppressed HepG2 cell proliferation in both a concentration- and time-dependent manner. Acetochlor induced reactive oxygen species (ROS) generation more than 700% with exposure to 400 µM acetochlor, and acetochlor decreased the activities and levels of anti-oxidant responses (superoxide dismutase, glutathione) following exposure to 100 µM, 200 µM and 400 µM acetochlor. Acetochlor also (1) induced HepG2 cell damage through apoptotic-signaling pathways; (2) enhanced intracellular free Ca2+ concentration (>400%); (3) decreased mitochondrial transmembrane potential (∼77%), and reduced ATP levels (∼65%) following exposure to 400 µM acetochlor compared to untreated cells. Notably, cell cycle progression was blocked at G0/G1 phase in HepG2 cells when treated for 24 h with 400 µM acetochlor. Taken together, acetochlor induced significant cytotoxicity toward HepG2 cells, and the underlying toxicity mechanisms appear to be related to ROS generation, mitochondrial dysfunction and disruption in the cell cycle regulation. These data contribute to toxicity assessments for acetochlor, a high-use herbicide, to quantify risk to wildlife and human health.

5.
J Food Sci ; 84(12): 3601-3607, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31730276

RESUMO

Sturgeon meat has been found to be suitable as surimi raw materials. The present study determined the modori phenomenon in sturgeon surimi gels and identified its relationship with cathepsins. In all heat-treated gels (25 to 90 °C, at 5 °C intervals), the 40 °C-incubated sturgeon surimi gel showed the weakest gel properties and water-holding capacity (P < 0.05), a rough protein gel network under SEM, and the highest protein solubility and trichloroacetic acid-soluble peptides content (P < 0.05). SDS-PAGE indicated that the myosin heavy chain band of sturgeon surimi gels was almost completely degraded at 40 °C. Moreover, the highest cathepsin L activity was observed in 40 °C-treated sturgeon surimi gels (P < 0.05). Our results suggested that the modori phenomenon in sturgeon surimi gels occurred at 40 °C, which was partially attributed to cathepsin L, thereby allowing for the better exploitation and utilization of sturgeon surimi.

6.
Molecules ; 24(18)2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31505731

RESUMO

To expand the utilization of oyster protein (OP), the effects of high pressure (100 to 500 MPa) on chemical forces, structure, microstructure, and digestibility properties were investigated. High pressure (HP) treatment enhanced the electrostatic repulsion (from -13.3Control to -27.8HP200 mV) between protein molecules and avoided or retarded the formation of protein aggregates. In addition, the HP treated samples showed uniform distribution and small particle size. The changes in electrostatic interaction and particle size contributed to the improvement of solubility (from 10.53%Control to 19.92%HP500 at pH 7). The stretching and unfolding of protein were modified by HP treatment, and some internal hydrophobic groups and -SH groups were exposed. HP treatment modified the secondary structure of OP. The treated samples contained less α-helix and ß-sheet structures, whereas the proportions of ß-sheet and random coil structures were increased. The treated samples have high digestibility in the stomach (from 26.3%Control to 39.5%HP500) and in the total digestive process (from 62.1%Control to 83.7%HP500). In addition, the total digestive production showed higher percentages of small peptides (<1 kDa) after HP treatment. The protein solubility and digestibility were increased after HP treatment, and high solubility and high digestibility might increase the chance that OP become a kind of protein supplement.


Assuntos
Ostreidae/química , Pressão/efeitos adversos , Agregados Proteicos , Proteínas/química , Animais , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Peptídeos/química , Peptídeos/metabolismo , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Estrutura Secundária de Proteína , Proteínas/metabolismo , Solubilidade , Estômago/química
7.
Mater Sci Eng C Mater Biol Appl ; 105: 110102, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546340

RESUMO

The Hydroxyapatite (HA, Ca10(PO4)6(OH)2) has attracted widely research interests in many aspects, especially in repairing and replacing human hard tissues due to its brilliant biocompatibility, biological activity and so on. In the present article, HA nano-rods were rapidly developed via hydrothermal reaction synthesized with two representative surfactants (hexadecyltrimethylammonium bromide and sodium dodecyl sulfate) taken oyster shells as raw materials. The scanning electron microscopy (SEM) observations demonstrated that the micromorphology of synthesized HA was constructed of relatively regular nano-rods. From the zeta potential (ZP) analysis, the zeta potential of the developed HA was affected by different surfactants, which demonstrated the opposite potential value. The Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) results showed the HA phase was successfully and rapidly developed on the surface of oyster shell with the help of surfactants. The bio-safety of HA nano-rods was confirmed by MTT cytotoxicity assay using pre-osteoblasts cells. A possible hard-template transformation mechanism from the calcite and aragonite phases into the HA phase was proposed.

8.
J Food Biochem ; 43(2): e12730, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-31353647

RESUMO

Methodology to enhance the intestinal absorption of peptides is an important challenge due to their easily degradation and poor permeability across the intestinal epithelium. In this study, the fish-derived peptide (DGDDGEAGKIG)-loaded chitosan (CS) nanoparticles (CS/PEP-NPs) were prepared and investigated in Caco-2 monolayer model. The results indicated zeta potential of CS/PEP-NPs increased with the increase in molecular weight of CS (10-50 kDa). Transmission electron microscopy images revealed the CS/PEP-NPs were uniform spherical-shaped nanoparticles with a diameter of 50-200 nm (150 kDa). Compared to other CS/PEP-NPs, 150-kDa CS/PEP-NPs performed an outstanding apparent permeability coefficient (Papp, 2.29 × 10-5  cm s-1 ) and cumulative amount of peptide (120 min, 2,987 ng) in Caco-2 cells. CS/PEP-NPs could reduce the tight junction integrity of Caco-2 cells and enhance the intracellular fluorescence intensities of fluorescein isothiocyanate-labeled peptide. These findings suggest that chitosan nanoparticles are promising carriers to promote intestinal absorption of fish-derived peptide via paracellular pathway mediated by tight junctions. PRACTICAL APPLICATIONS: Chitosans are promising carriers to promote intestinal absorption of fish-derived peptide. The 150-kDa CS/PEP-NPs performed an outstanding apparent permeability coefficient (Papp, 2.29 × 10-5  cm s-1 ) and cumulative amount of peptide (120 min, 2,987 ng) in Caco-2 cells. CS/PEP-NPs could reduce the tight junction integrity of Caco-2 cells and enhance the peptide uptake by paracellular pathway. Chitosan nanoparticles can be developed as vehicles for enhancing the cellular uptake of peptide in food industry.

9.
Mar Drugs ; 17(6)2019 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-31181804

RESUMO

Zinc-binding peptides from oyster (Crassostrea gigas) have potential effects on zinc supplementation. The aim of this study was to prepare efficient zinc-binding peptides from oyster-modified hydrolysates by adding exogenous glutamate according to the plastein reaction and to further explore the zinc absorption mechanism of the peptide-zinc complex (MZ). The optimum conditions for the plastein reaction were as follows: pH 5.0, 40 °C, substrate concentration of 40%, pepsin dosage of 500 U/g, reaction time of 3 h and l-[1-13C]glutamate concentration of 10 mg/mL. The results of 13C isotope labelling suggested that the addition of l-[1-13C]glutamate contributed to the increase in the zinc-binding capacity of the peptide. The hydrophobic interaction was the main mechanism of action of the plastein reaction. Ultraviolet spectra and scanning electronic microscopy (SEM) revealed that the zinc-binding peptide could bind with zinc and form MZ. Furthermore, MZ could significantly enhance zinc bioavailability in the presence of phytic acid, compared to the commonly used ZnSO4. Additionally, MZ significantly promoted the intestinal absorption of zinc mainly through two pathways, the zinc ion channel and the small peptide transport pathway. Our work attempted to increase the understanding of the zinc absorption mechanism of MZ and to support the potential application of MZ as a supplementary medicine.


Assuntos
Técnicas de Química Analítica/métodos , Absorção Intestinal/efeitos dos fármacos , Ostreidae/química , Peptídeos/química , Peptídeos/farmacologia , Zinco/química , Zinco/metabolismo , Animais , Disponibilidade Biológica , Quelantes/química , Hidrolisados de Proteína/química
10.
Mol Nutr Food Res ; 63(18): e1900326, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31237989

RESUMO

SCOPE: Decreasing ß-amyloid (Aß) accumulation is of significance in finding therapeutic candidates for cognitive impairments in Alzheimer's disease (AD). The aim of this study is to investigate the potency of the active components of walnut protein in decreasing Aß aggregation and ameliorating cognitive impairments. METHODS AND RESULTS: Cell model of intracellular Aß42 aggregation is used to explore the active ingredients in walnut protein hydrolysate (WPH). A bioactive peptide (Pro-Pro-Lys-Asn-Trp, PW5) with great anti-Aß42 aggregation activity identified from the WPH is synthesized for in vitro and in vivo experiments. Using classic APP/PS1 mouse model, it is validated that PW5 exerts its effects on cognitive improvement through reducing Aß plaques accumulation. Moreover, metabolomic analysis reveals that serum norepinephrine (NE) and isovalerate levels are significantly increased in response to PW5 intervention, with decreased serum levels of acetylcholine (AChe) and valerate, compared with the vehicle-treated APP/PS1 mice. PW5 feeding also improves gut dysbiosis in APP/PS1 transgenic mice by increasing the relative abundance of Firmicutes and decreasing Proteobacteria and Verrucomicrobia as displayed by 16s rRNA analyses. CONCLUSIONS: These promising results support the utilization of peptide PW5 as an active ingredient in functional foods or potential drug candidate for the prevention and/or treatment of AD.

11.
Food Funct ; 10(6): 3439-3451, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31139782

RESUMO

This study first investigates how the intake level of glycated fish protein (GP), enriched with Amadori products, affects gut health by modifying the fermentation of gut microbiota and accumulation of advanced glycation end products (AGEs) in rats fed a high-fat diet. Hyperlipidemic rats were fed a fish protein (FP) control diet, 6% low-level GP (L-GP) diet, and 12% high-level GP (H-GP) diet for four weeks. Compared to the FP diet, the GP diet greatly changed the pattern of protein fermentation and reduced inflammation markers and blood lipids, but increased the AGE plasma accumulation and fecal excretion. Furthermore, the GP supplementation significantly decreased Ruminiclostridium_6 and Desulfovibrio (p < 0.05), and the L-GP diet showed more effects on the increase of butyrate-producing Ruminococcus_1 and Roseburia, while the H-GP diet considerably decreased Helicobacter and Lachnospiraceae_NK4A136_group. Correlation-type principal-component analysis (PCA) clearly indicated that these biological effects of intake of GP were related to the modulation of gut microbiota composition and fermentation metabolite profiles. Overall, the low intake level of glycated fish protein may have a more beneficial effect on gut health.


Assuntos
Proteínas de Peixes/química , Proteínas de Peixes/metabolismo , Microbioma Gastrointestinal , Trato Gastrointestinal/imunologia , Produtos Finais de Glicação Avançada/metabolismo , Hiperlipidemias/dietoterapia , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Dieta Hiperlipídica/efeitos adversos , Feminino , Trato Gastrointestinal/metabolismo , Trato Gastrointestinal/microbiologia , Produtos Finais de Glicação Avançada/química , Humanos , Hiperlipidemias/etiologia , Hiperlipidemias/imunologia , Hiperlipidemias/microbiologia , Masculino , Ratos , Ratos Sprague-Dawley
12.
J Ethnopharmacol ; 238: 111836, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-30922853

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: ZhiShiXiaoPi Tang (ZSXPT) is a Chinese traditional medicine formula that contains 10 Chinese traditional medicine substances. It has been widely used to treat patients with functional dyspepsia (FD). However, the protective effect of ZSXPT and its molecular mechanisms in FD still remain elusive. AIM OF THE STUDY: To investigate the protective effect of ZSXPT on autophagy induced by Corticosterone (Cort) in PC12 cells which have typical neuron characteristics and have been widely used as a model system for depression studies and FD rats, and explore its underlying mechanisms. MATERIALS AND METHODS: In this study, high-performance liquid chromatography fingerprint analysis was performed to characterize the chemical composition of ZSXPT. Depression-induced autophagy, ROS generation, and changes in mitochondrial membrane potential (MMP) were investigated in Cort-induced PC12 cells and in FD rats to evaluate the protective effects of ZSXPT. RESULTS: Our results show that ZSXPT treatment protects neurons against Cort-induced damage and apoptosis by increasing cell viability and reducing the release of lactate dehydrogenase. ZSXPT decreased Cort-induced ROS generation, increased MMP, and accelerated autophagy through the blockade of the mammalian target of rapamycin (mTOR) pathway. Moreover, we observed similar findings when we studied ZSXPT in a rat model of FD. CONCLUSIONS: Our in vitro and in vivo results indicate that the neuroprotective effect of ZSXPT against autophagy-induced damage and apoptosis occurs mainly by blocking the mTOR pathway in Cort-induced PC12 cells and in FD rats. Taken together, these data provide reliable experimental evidence and explain the molecular mechanism by which ZSXPT ameliorates FD.


Assuntos
Autofagia/efeitos dos fármacos , Dispepsia/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Corticosterona , Esvaziamento Gástrico/efeitos dos fármacos , Motilidade Gastrointestinal/efeitos dos fármacos , Masculino , Medicina Tradicional Chinesa , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Células PC12 , Ratos , Ratos Sprague-Dawley , Serina-Treonina Quinases TOR/metabolismo
13.
Artigo em Inglês | MEDLINE | ID: mdl-30909451

RESUMO

The single toxicity (IC50) of zinc (Zn) and 11 nitro-substituted benzenes to Photobacterium phosphoreum were determined, respectively. On basis of single toxicity, the joint toxicity of binary mixtures of Zn and 11 nitro-substituted benzenes at different Zn concentrations of 0.2 IC50, 0.5 IC50, and 0.8 IC50 were measured. The joint toxicity was evaluated by toxic unit (TU) and additive index (AI) methods. The results indicated that the joint toxicity was not only depending on the Zn concentrations but also on the substituted groups of nitro-substituted benzenes. The quantitative structure-activity relation (QSAR) equations were developed and the results showed that the toxicity of nitro-substituted benzenes has different joint effect at the different Zn concentrations. At the Zn concentration of 0.2 IC50, the binary joint effects were mainly antagonism and the joint toxicity was negatively related to descriptors called VE2_B(p) and TIC3. At the Zn concentration of 0.5 IC50 and 0.8 IC50, the binary joint effects were mainly antagonism and simple addition, and the joint toxicity was related to the same descriptor Eig06_ AEA(dm). It indicated that the joint toxic actions were similar when combined at the medium and high concentrations of Zn.


Assuntos
Benzeno/toxicidade , Photobacterium/efeitos dos fármacos , Relação Quantitativa Estrutura-Atividade , Zinco/toxicidade , Benzeno/química
14.
Mar Drugs ; 17(3)2019 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-30889794

RESUMO

Alginate oligosaccharides (AlgO), agarose oligosaccharides (AO), and κ-carrageenan oligosaccharides (KCO) were obtained by specific enzymatic hydrolysis method. The molecular weight distributions of the three oligosaccharides were 1.0⁻5.0 kDa, 0.4⁻1.4 kDa, and 1.0⁻7.0 kDa, respectively. The culture medium was supplemented with the three oligosaccharides and fermented by pig fecal microbiota in vitro, for 24 h. Each oligosaccharide was capable of increasing the concentration of short-chain fatty acids (SCFAs), especially butyric acid, and altering the microbiota composition. Linear discriminant analysis effect size (LEfSe) analysis results showed that the opportunistic pathogenic bacteria Escherichia, Shigella, and Peptoniphilus, were significantly decreased in AlgO supplemented medium. AO could improve the gut microbiota composition by enriching the abundance of Ruminococcaceae, Coprococcus, Roseburia, and Faecalibacterium. Besides, KCO could increase the abundance of SCFA microbial producers and opportunistic pathogenic flora. Therefore, these results indicate that AlgO and AO can be used as gut microbial regulators and can potentially improve animal/human gastrointestinal health and prevent gut disease, whereas the physiological function of KCO needs further evaluation.


Assuntos
Organismos Aquáticos/química , Bactérias/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Oligossacarídeos/administração & dosagem , Prebióticos/administração & dosagem , Alginatos/administração & dosagem , Alginatos/química , Alginatos/isolamento & purificação , Animais , Bactérias/isolamento & purificação , Carragenina/administração & dosagem , Carragenina/química , Carragenina/isolamento & purificação , Fezes/microbiologia , Hidrólise , Oligossacarídeos/química , Oligossacarídeos/isolamento & purificação , Feófitas/química , Rodófitas/química , Alga Marinha/química , Sefarose/administração & dosagem , Sefarose/química , Sefarose/isolamento & purificação , Suínos
15.
Molecules ; 24(4)2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30781435

RESUMO

This study investigated the effects of α-tocopherol (α-TOH) on the physicochemical properties of sturgeon surimi during 16-week storage at -18 °C. An aliquot of 0.1% (w/w) of α-TOH was added into the surimi and subjected to frozen storage, and 8% of a conventional cryoprotectant (4% sorbitol and 4% sucrose, w/w) was used as a positive control. Based on total viable count, pH and whiteness, α-TOH exhibited a better protection for frozen sturgeon surimi than cryoprotectant during frozen storage. According to soluble protein content, carbonyl content, total sulfhydryl content, and surface hydrophobicity, α-TOH and cryoprotectant showed the same effects on retarding changes of proteins. The results of breaking force, deformation, gel strength, water-holding capacity and microstructure of sturgeon surimi indicated that the gel properties of frozen sturgeon surimi were retained by α-TOH. Our results suggest that α-TOH is an attractive candidate to maintain the quality of sturgeon surimi during frozen storage.


Assuntos
Crioprotetores/farmacologia , Peixes/metabolismo , Congelamento , alfa-Tocoferol/farmacologia , Animais , Produtos Pesqueiros/análise , Produtos Pesqueiros/microbiologia , Conservação de Alimentos/métodos , Armazenamento de Alimentos/métodos , Compostos de Sulfidrila/metabolismo
16.
Int J Biol Macromol ; 127: 349-356, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30615968

RESUMO

ε-Poly-l-lysine (PL) has high antimicrobial activity and a wide antimicrobial spectrum and is applied broadly in the food industry. However, PL may lose part of its activity in phosphate systems, which are typically used in seafood processing. To enhance antimicrobial activity under high phosphate conditions, DNA/PL nanoparticles were fabricated via the nanoprecipitation method. The DNA/PL nanoparticle size was smallest when the ethanol to water ratio was 7:1, and the mean diameter was 101 nm. UV-vis showed hypochromism and a redshift of the DNA in the presence of PL, indicating an intercalative interaction between DNA and PL. FTIR spectroscopy revealed that strong hydrogen bonds and hydrophobic interactions were involved in DNA/PL nanoparticle formation. Compared with that of PL, the antimicrobial activity of the nanoparticles against S. aureus, B. subtilis, and E. coli was enhanced. Additionally, the DNA/PL nanoparticles still retained higher antimicrobial activity in the phosphate system than free PL. The antimicrobial mechanistic analysis provided evidence that the DNA/PL nanoparticles showed high bioactivity due to cell membrane damage. This work provides a potential method to enhance the antimicrobial activity of PL under adverse conditions, which can promote the application of PL in seafood containing phosphate compounds.


Assuntos
Antibacterianos , Bactérias/crescimento & desenvolvimento , Adutos de DNA , Lisina/análogos & derivados , Nanopartículas/química , Fosfatos/química , Polilisina , Antibacterianos/química , Antibacterianos/farmacologia , Adutos de DNA/química , Adutos de DNA/farmacologia , Lisina/química , Lisina/farmacologia , Polilisina/química , Polilisina/farmacologia
17.
Water Res ; 151: 468-477, 2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30640160

RESUMO

The hydrated electron (eaq-)-based reduction processes are promising for removing organic pollutants in water engineering systems. The reductive kinetics, especially the second order rate constants ( [Formula: see text] ) of eaq- with organic compounds, is important for evaluating and modeling the advanced reduction processes. In this study, the [Formula: see text] values for aliphatic compounds and phenyl-based compounds are, for the first time, modeled by the quantitative structure-activity relationship (QSAR) method. The structural features governing the reactivity of two classes of organic compounds toward eaq- were revealed, and the energy of the lowest unoccupied molecular orbital (ELUMO), one-electron reduction potential (ERED) and polarizability (α) were found to be the important molecular parameters in both two models. The built QSAR models provide robust predictive tools for estimating the removal of emerging pollutants using eaq- during wastewater treatment processes. Additionally, quantum chemical calculations were employed to probe into the mechanism and feasibility of the single electron transfer (SET) pathway in the eaq--based reduction process. The thermodynamic investigation suggests that the compounds with electron-withdrawing groups tend to possess higher [Formula: see text] and lower Gibbs free energy (ΔGSET) and Gibbs free energies of activation (∆‡GSET∘) than the ones with electron-donating groups, indicating the SET process occurs more readily. It is also found that the refractory halogenated compounds can achieve dehalogenation via the SET pathway.


Assuntos
Relação Quantitativa Estrutura-Atividade , Poluentes Químicos da Água , Elétrons , Oxirredução , Águas Residuárias
18.
Mar Drugs ; 17(12)2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31888208

RESUMO

Siderophores are iron chelators with low molecular weight secreted by microorganisms. Siderophores have the potential to become natural iron fortifiers. To explore the feasibility of the application of Synechococcus sp. PCC7002-derived siderophores as iron fortifiers, Synechococcus sp. PCC7002, as a carrier, was fermented to produce siderophores. The absorption mechanism and anemia intervention effect of siderophores-chelated iron (SCI) were studied through the polarized Caco-2 Cell monolayers and the rat model of iron-deficiency anemia, respectively. The results indicated that siderophores (from Synechococcus sp. PCC7002) had an enhancing effect on iron absorption in polarized Caco-2 cell monolayers. The main absorption site of SCI was duodenum with pH 5.5, and the absorption methods included endocytosis and DMT1, with endocytosis being dominant. The effect of sodium phytate on SCI was less than that of ferrous sulfate. Therefore, SCI could resist inhibitory iron absorption factors in polarized Caco-2 cell monolayers. SCI showed significantly higher relative bioavailability (133.58 ± 15.42%) than ferrous sulfate (100 ± 14.84%) and ferric citrate (66.34 ± 8.715%) in the rat model. Food intake, hemoglobin concentration, and hematocrit and serum iron concentration of rats improved significantly after Fe-repletion. Overall, this study indicated that siderophores derived from Synechococcus sp. PCC7002 could be an effective and feasible iron nutritive fortifier.

19.
Mar Drugs ; 16(10)2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-30308963

RESUMO

In this paper, a novel natural influenza A H1N1 virus neuraminidase (NA) inhibitory peptide derived from cod skin hydrolysates was purified and its antiviral mechanism was explored. From the hydrolysates, novel efficient NA-inhibitory peptides were purified by a sequential approach utilizing an ultrafiltration membrane (5000 Da), sephadex G-15 gel column and reverse-phase high-performance liquid chromatography (RP-HPLC). The amino acid sequence of the pure peptide was determined by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) was PGEKGPSGEAGTAGPPGTPGPQGL, with a molecular weight of 2163 Da. The analysis of the Lineweacer⁻Burk model indicated that the peptide was a competitive NA inhibitor with Ki of 0.29 mM and could directly bind free enzymes. In addition, docking studies suggested that hydrogen binding might be the driving force for the binding affinity of PGEKGPSGEAGTAGPPGTPGPQGL to NA. The cytopathic effect reduction assay showed that the peptide PGEKGPSGEAGTAGPPGTPGPQGL protected Madin⁻Darby canine kidney (MDCK) cells from viral infection and reduced the viral production in a dose-dependent manner. The EC50 value was 471 ± 12 µg/mL against H1N1. Time-course analysis showed that PGEKGPSGEAGTAGPPGTPGPQGL inhibited influenza virus in the early stage of the infectious cycle. The virus titers assay indicated that the NA-inhibitory peptide PGEKGPSGEAGTAGPPGTPGPQGL could directly affect the virus toxicity and adsorption by host cells, further proving that the peptide had an anti-viral effect with multiple target sites. The activity of NA-inhibitory peptide was almost inactivated during the simulated in vitro gastrointestinal digestion, suggesting that oral administration is not recommended. The peptide PGEKGPSGEAGTAGPPGTPGPQGL acts as a neuraminidase blocker to inhibit influenza A virus in MDCK cells. Thus, the peptide PGEKGPSGEAGTAGPPGTPGPQGL has potential utility in the treatment of the influenza virus infection.


Assuntos
Antivirais/farmacologia , Gadus morhua/metabolismo , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Neuraminidase/antagonistas & inibidores , Peptídeos/farmacologia , Pele/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular , Cães , Células Madin Darby de Rim Canino , Peso Molecular , Infecções por Orthomyxoviridae/tratamento farmacológico , Carga Viral/métodos
20.
Mar Drugs ; 16(9)2018 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-30201855

RESUMO

Probiotic-derived polyphosphates have attracted interest as potential therapeutic agents to improve intestinal health. The current study discovered the intracellular accumulation of polyphosphates in a marine cyanobacterium Synechococcus sp. PCC 7002 as nano-sized granules. The maximum accumulation of polyphosphates in Synechococcus sp. PCC 7002 was found at the late logarithmic growth phase when the medium contained 0.74 mM of KH2PO4, 11.76 mM of NaNO3, and 30.42 mM of Na2SO4. Biogenic polyphosphate nanoparticles (BPNPs) were obtained intact from the algae cells by hot water extraction, and were purified to remove the organic impurities by Sephadex G-100 gel filtration. By using 100 kDa ultrafiltration, BPNPs were fractionated into the larger and smaller populations with diameters ranging between 30⁻70 nm and 10⁻30 nm, respectively. 4',6-diamidino-2-phenylindole fluorescence and orthophosphate production revealed that a minor portion of BPNPs (about 14⁻18%) were degraded during simulated gastrointestinal digestion. In vitro studies using lipopolysaccharide-activated RAW264.7 cells showed that BPNPs inhibited cyclooxygenase-2, inducible nitric oxide (NO) synthase expression, and the production of proinflammatory mediators, including NO, tumor necrosis factor-α, interleukin-6, and interleukin-1ß through suppressing the Toll-like receptor 4/NF-κB signaling pathway. Overall, there is promise in the use of the marine cyanobacterium Synechococcus sp. PCC 7002 to produce BPNPs, an anti-inflammatory postbiotic.


Assuntos
Anti-Inflamatórios/farmacologia , Produtos Biológicos/farmacologia , Nanopartículas , Polifosfatos/farmacologia , Transdução de Sinais/efeitos dos fármacos , Synechococcus/metabolismo , Animais , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/metabolismo , Produtos Biológicos/isolamento & purificação , Produtos Biológicos/metabolismo , Mediadores da Inflamação/metabolismo , Lipopolissacarídeos/imunologia , Camundongos , Polifosfatos/isolamento & purificação , Polifosfatos/metabolismo , Células RAW 264.7 , Transdução de Sinais/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA