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981.
Didley Sâmia Paiva Cazelli Maria Eduarda Sousa Barroso Rafael Brianti Pizi Marina Orlandi Thiago Belarmino de Souza Diogo Teixeira Carvalho Arlan da Silva Gonçalves Denise Coutinho Endringer 《Chemical Papers》2017,71(10):1877-1886
Sortase A is responsible for the virulence of Gram-positive pathogens, including staphylococci and streptococci. The LPETG is the peptide surface anchor signal for Sortase A. The inhibitors of this enzyme shared similar binding pattern with substrate LPETG. Eugenol and its derivatives may act as sortase A inhibitor. The antimicrobial activity of eugenol and its derivatives was tested in vitro against bacterial strains: Staphylococcus aureus, Streptococcus mutans and Escherichia coli. All the tested derivatives demonstrated antimicrobial activity. Differences between derivatives in terms of in vitro activity and interactions between the amino acid residues were correlated in the docking analysis for the same derivatives. According to the relationship observed in this study between the antimicrobial activity of eugenol and the LPETG peptide structure, some of the eugenol derivatives proved to be more active inhibiting sortase A than eugenol against microorganisms when tested at the same concentrations. 相似文献
982.
Matos Charlene R. S. Souza Helio O. Santana Tiago B. S. Candido Luan P. M. Cunha Frederico G. C. Sussuchi Eliana M. Gimenez Iara F. 《Mikrochimica acta》2017,184(6):1755-1764
Microchimica Acta - This work describes the synthesis of a glutathione-capped Cd1-xMgxTe semiconductor nanocrystal alloy in aqueous solution. The effects of reaction time and Cd:Mg molar proportion... 相似文献
983.
Gaspar Diaz-Muñoz Raquel Geralda Isidorio Izabel Luzia Miranda Gabriel Nunes de Souza Dias Marisa Alves Nogueira Diaz 《Tetrahedron letters》2017,58(33):3311-3315
The present study describes the total synthesis of 1,2,3,4-tetrahydroquinoline alkaloids (±)-galipinine, (±)-cuspareine, (±)-galipeine and (±)-angustureine, in three steps and high yields (78%, 76%, 74%, and 66%, respectively) from common aldehyde and the ylide respectives. The key step of this approach is based on an unusual Wittig reaction by using the phase transfer medium (aq. NaOH/CH2Cl2 1:1 or t-BuOK/t-BuOH/CH2Cl2 1:1), affording olefinic intermediates in high yields. 相似文献
984.
Simultaneous determination of amino acids and neurotransmitters in plasma samples from schizophrenic patients by hydrophilic interaction liquid chromatography with tandem mass spectrometry 下载免费PDF全文
Diego Soares Domingues Eduardo José Crevelin Luiz Alberto Beraldo de Moraes Jaime Eduardo Cecilio Hallak José Alexandre de Souza Crippa Maria Eugênia Costa Queiroz 《Journal of separation science》2015,38(5):780-787
A sensitive, reproducible, and rapid method was developed for the simultaneous determination of underivatized amino acids (aspartate, serine, glycine, alanine, methionine, leucine, tyrosine, and tryptophan) and neurotransmitters (glutamate and γ‐aminobutyric acid) in plasma samples using hydrophilic interaction liquid chromatography coupled to triple quadrupole tandem mass spectrometry. The plasma concentrations of amino acids and neurotransmitters obtained from 35 schizophrenic patients in treatment with clozapine (27 patients) and olanzapine (eight patients) were compared with those obtained from 38 healthy volunteers to monitor the effectiveness of treatment. The chromatographic conditions separated ten target compounds within 3 min. This method presented linear ranges that varied from (lower limit of quantification: 9.7–13.3 nmol/mL) to (upper limit of quantification: 19.4–800 nmol/mL), intra‐ and interassay precision with coefficients of variation lower than 10%, and relative standard error values of the accuracy ranged from –2.1 to 9.9%. The proposed method appropriately determines amino acids and neurotransmitters in plasma from schizophrenic patients. Compared with the control group (healthy volunteers), the plasma levels of methionine in schizophrenic patients treated with olanzapine are statistically significantly higher. Moreover, schizophrenic patients treated with clozapine tend to have increased plasma levels of glutamate. 相似文献
985.
J.-C. M’Peko M.F. De Souza C.L. Da Silva D.P.F. De Souza 《Applied Physics A: Materials Science & Processing》2007,89(2):509-515
Yttria-doped ceria ceramics were prepared and reduced in an oxygen-deficient (argon) ambient. Electrical characterization
through impedance spectroscopy revealed ionic-type conduction processes in as-sintered samples, with grain–bulk and grain–boundary
activation energies (H) of about 1.00 eV and 1.05 eV, respectively. Electrical results from the reduced materials showed a
predominant electronic-type, relatively high conductivity for the grains (H=0.52 eV), in contrast to a still ionic-like, relatively
poor conductivity for the grain boundaries (H=0.95 eV). With the support of the results processed after re-oxidizing the materials
in air combined with information from literature, this apparently contradictory behavior is discussed in terms of electron
trapping at (Ce3+:)-type defect complexes. The overall work strongly supports the idea that surfaces (e.g., grain boundaries) in polycrystalline
ceria are indeed much more sensitive to redox interactions than lattice.
PACS 72.20.-i; 72.60.+g; 72.80.-r 相似文献
986.
Filgueira Dde M Salomão de Freitas DP de Souza Votto AP Fillmann G Monserrat JM Geracitano LA Santos Trindade G 《Photochemistry and photobiology》2007,83(6):1358-1363
Benzo[a]pyrene (BaP) is ubiquitously distributed in the environment, being considered the most phototoxic element among polycyclic aromatic hydrocarbon (PAHs). In presence of oxygen, PAHs can act as a photosensitizer by means of promoting photo-oxidation of biological molecules (photodynamic action, PDA). Thus, the present study analyzed the photodynamic action of BaP under UVA irradiation (BaP + UVA) and its oxidative effects on K562 cells. The evaluation of BaP kinetics showed that the highest intracellular concentration occurred after 18 h of incubation. Cell viability, reactive oxygen species (ROS) generation, lipid peroxidation, DNA damage (breaks and DNA-protein cross-link [DNAPC]) were assessed after exposure to BaP, UVA and BaP plus UVA irradiation (BaP + UVA). Cell viability was decreased just after exposure to BaP + UVA. Lipid peroxidation and DNA breaks increased after BaP + UVA exposure, while the DNAPC increased after BaP, UVA and BaP + UVA exposure, suggesting that BaP + UVA effects were a consequence of both type II (producing mainly singlet oxygen) and type I (producing others ROS) mechanisms of PDA. 相似文献
987.
Téllez Soto CA Ramos JM Rianelli RS de Souza MC Ferreira VF 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,67(3-4):1080-1087
The 2-diazo-5,5-dimethyl-cyclohexane-1,3-dione (3) was synthesized and the FT-IR/Raman spectra were measured with the purpose of obtain a full assignment of the vibrational modes. Singular aspects concerning the -CNN oscillator are discussed in view of two strong bands observed in the region of 2300-2100 cm(-1) in both, Infrared and Raman spectra. The density functional theory (DFT) was used to obtain the geometrical structure and for assisting in the vibrational assignment joint to the traditional normal coordinate analysis (NCA). The observed wavenumbers at 2145 (IR), 2144(R) are assigned as the coupled nu(NN)+nu(CN) vibrational mode with higher participation of the NN stretching. A 2188 cm(-1) (IR) and at 2186 cm(-1) (R) can be assigned as a overtone of one of nu(CC) normal mode or to a combination band of the fundamentals delta(CCH) found at 1169 cm(-1) and the delta (CCN) found at 1017 cm(-1) enhanced by Fermi resonance. 相似文献
988.
Weslley Souza Paiva Francisco Ernesto de Souza Neto Moacir Fernandes Queiroz Lucas Alighieri Neves Costa Batista Hugo Alexandre Oliveira Rocha Anabelle Camarotti de Lima Batista 《Molecules (Basel, Switzerland)》2022,27(1)
Animal chitosan (Chit-A) is gaining more acceptance in daily activities. It is used in a range of products from food supplements for weight loss to even raw materials for producing nanoparticles and hydrogel drug carriers; however, it has low antioxidant activity. Fungal oligochitosan (OChit-F) was identified as a potential substitute for Chit-A. Cunninghamella elegans is a fungus found in the Brazilian savanna (Caatinga) that produces OligoChit-F, which is a relatively poorly studied compound. In this study, 4 kDa OChit-F with a 76% deacetylation degree was extracted from C. elegans. OChit-F showed antioxidant activity similar to that of Chit-A in only one in vitro test (copper chelation) but exhibited higher activity than that of Chit-A in three other tests (reducing power, hydroxyl radical scavenging, and iron chelation). These results indicate that OChit-F is a better antioxidant than Chit-A. In addition, Chit-A significantly increased the formation of calcium oxalate crystals in vitro, particularly those of the monohydrate (COM) type; however, OChit-F had no effect on this process in vitro. In summary, OChit-F had higher antioxidant activity than Chit-A and did not induce the formation of CaOx crystals. Thus, OChit-F can be used as a Chit-A substitute in applications affected by oxidative stress. 相似文献
989.
Leilson de Oliveira Ribeiro Beatriz Pereira de Freitas Carolline Margot Albanez Lorentino Heloisa Freire Frota Andr Luis Souza dos Santos Davyson de Lima Moreira Bruno Srgio do Amaral Eliane Przytyk Jung Claudete Norie Kunigami 《Molecules (Basel, Switzerland)》2022,27(2)
Herein, the extraction of bioactive compounds from umbu fruit peel was optimized using thermal-assisted solid–liquid extraction. In parallel, antioxidant, antimicrobial, and inhibitory effects against α-amylase of optimized extract were also evaluated. The combination of operational conditions including the temperature (32–74 °C), ethanol concentration (13–97%), and solid/liquid ratio (1:10–1:60; w/v) was employed using a rotational central composite design for optimization. The extracts were evaluated for total phenolic compounds (TPC), total flavonoid compounds (TFC) and antioxidant capacity by ABTS•+, DPPH• and FRAP assays. The bioactive profile of the optimized extract was obtained by ultra-performance liquid chromatography coupled to quadrupole/time-of-flight mass spectrometry in electrospray ionization in both negative and positive modes. The statistically evaluated results showed that the optimal operational conditions for the recovery of bioactive compounds from umbu fruit peel included 74 °C, 37% ethanol, and a solid–liquid ratio of 1:38. Under these conditions, the obtained values were 1985 mg GAE/100 g, 1364 mg RE/100 g, 122 µmol TE/g, 174 µmol/TE g and 468 µmol Fe2+/g for TPC, TFC, ABTS•+, DPPH•, and FRAP assays, respectively. In addition, the optimized extract was effective against Gram-positive and Gram-negative bacteria (MBC ranged from 0.060 to 0.24 mg GAE/mL), as well as it was effective to inhibit α-amylase (IC50 value of 0.076 mg GAE/mL). The optimized extract showed to be mainly constituted by phenolic acids and flavonoids. 相似文献
990.
Mateus Alves Batista Abraho Victor Tavares de Lima Teixeira dos Santos Aline Lopes do Nascimento Luiz Fernando Moreira Indira Ramos Senna Souza Heitor Ribeiro da Silva Arlindo Csar Matias Pereira Lorane Izabel da Silva Hage-Melim Jos Carlos Tavares Carvalho 《Molecules (Basel, Switzerland)》2022,27(5)
Some significant compounds present in annatto are geranylgeraniol and tocotrienols. These compounds have beneficial effects against hyperlipidemia and chronic diseases, where oxidative stress and inflammation are present, but the exact mechanism of action of such activities is still a subject of research. This study aimed to evaluate possible mechanisms of action that could be underlying the activities of these molecules. For this, in silico approaches such as ligand topology (PASS and SEA servers) and molecular docking with the software GOLD were used. Additionally, we screened some pharmacokinetic and toxicological parameters using the servers PreADMET, SwissADME, and ProTox-II. The results corroborate the antidyslipidemia and anti-inflammatory activities of geranylgeraniol and tocotrienols. Notably, some new mechanisms of action were predicted to be potentially underlying the activities of these compounds, including inhibition of squalene monooxygenase, lanosterol synthase, and phospholipase A2. These results give new insight into new mechanisms of action involved in these molecules from annatto and Chronic®. 相似文献