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1.
Comput Biol Med ; 119: 103673, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32339118

RESUMO

In this study, the influence of the sampling frequency and number of strides on recurrence quantifiers extracted from gait data was investigated in order to provide baseline values and preserve the system's non-linear dynamical characteristics expressed by these recurrence quantifiers. Recurrence quantifiers were extracted from a recurrence plot (RP), which required the reconstruction of a high-dimensional state space capable of reproducing the dynamical characteristics of the analyzed system. In this study, the following quantifiers were extracted: rate of recurrence (RR), determinism (DET), average diagonal lines length (AVG), maximum diagonal lines length (MaxL), Shannon entropy (EntD), and measure of trend (TREND). Data collected during treadmill walking were statistically analyzed to compare the distribution characteristics (mean, median, and standard deviation) and the quantifiers' correlation with those obtained from a control time series with an acquisition time corresponding to 150 strides and a 100-Hz sampling frequency, which are common values used in gait studies. It was not possible to reduce the number of strides for the MaxL or TREND. However, for the RR, DET, AVG, and EntD, it was possible to reduce the number of strides by 60% when analyzed together. The minimum sampling frequency required to extract all quantifiers simultaneously was 100 Hz. This potential reduction in the number of strides is appropriate for evaluating fast gait events, with short temporal localization in the RP, by applying the sliding window method to the recurrence plot.

2.
Environ Pollut ; 262: 114216, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32155546

RESUMO

The present study proposes a maize sprouts hydroponic growth model to evaluate the As, Cd, Cr and Pb translocation from multinutrient fertilizer and to do speciation of As and Cr in this fertilizer and As in parts of plant in order to predict their phytoavailability. X-ray absorption near edge structure (XANES) was employed to speciate As and Cr directly on fertilizer solid sample. Arsenate (AsV) and a solid solution of FeCrO3 were the major species identified in the samples. The sprouts were hydroponically cultivated in water, fertilizer slurry and fertilizer extract media. Concentrations of As, Cd and Pb measured on leaves of maize sprouts ranged from 0.061 to 0.31 mg kg-1, whereas Cr was not translocated to the aerial parts of sprouts. High performance liquid chromatographic with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) analysis was used to determine As speciation in maize sprouts, as well as in the fertilizer extracts and slurries. Arsenate was the only species identified in the initial fertilizer extract and this information is in agreement with the XANES results. However, the reduction of arsenate to arsenite was observed in extracts and slurries collected after sprout growth, probably due to the action of exudates secreted by plant roots. Arsenite was the predominant species identified in sprouts, the high phosphate concentration in the medium may have contributed to reduce arsenate phytoavailability.

3.
Front Microbiol ; 10: 2358, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31681221

RESUMO

The biogenicity problem of geological materials is one of the most challenging ones in the field of paleo and astrobiology. As one goes deeper in time, the traces of life become feeble and ambiguous, blending with the surrounding geology. Well-preserved metasedimentary rocks from the Archaean are relatively rare, and in very few cases contain structures resembling biological traces or fossils. These putative biosignatures have been studied for decades and many biogenicity criteria have been developed, but there is still no consensus for many of the proposed structures. Synchrotron-based techniques, especially on new generation sources, have the potential for contributing to this field of research, providing high sensitivity and resolution that can be advantageous for different scientific problems. Exploring the X-ray and matter interactions on a range of geological materials can provide insights on morphology, elemental composition, oxidation states, crystalline structure, magnetic properties, and others, which can measurably contribute to the investigation of biogenicity of putative biosignatures. Here, we provide an overview of selected synchrotron-based techniques that have the potential to be applied in different types of questions on the study of biosignatures preserved in the geological record. The development of 3rd and recently 4th generation synchrotron sources will favor a deeper understanding of the earliest records of life on Earth and also bring up potential analytical approaches to be applied for the search of biosignatures in meteorites and samples returned from Mars in the near future.

4.
J Wrist Surg ; 8(5): 408-415, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31579551

RESUMO

Background Despite the high prevalence of unstable distal radius fractures (DRFs), there is no consensus regarding the optimal method and treatment timing, especially for elderly patients with multiple associated injuries. Purpose This study aimed to compare the grip strength achieved with two different methods for definitive dynamic external fixation of DRFs in elderly patients with polytrauma operated on within the first 24 hours. Methods In this prospective randomized trial, 35 patients were assigned to undergo definitive external dynamic fixation of DRFs using the nonbridging (group A) or bridging (group B) method. The grip strength, range of motion (ROM), Disabilities of the Arm, Shoulder and Hand (QuickDASH) outcome measure, visual analog scale (VAS) score for pain, and radiographic characteristics were evaluated at 6 and 12 months. Results At 12 months, no significant between-group difference was observed with respect to grip strength. All patients showed results in the third or fourth quartiles. The mean ROMs were 96.94 and 96.38% and the mean QuickDASH scores were 3.53 and 3.85 in groups A and B, respectively. The VAS scores were 1.60 and 1.85 in groups A and B, respectively. The overall complication rates were 13.3 and 15% in groups A and B, respectively. Initial fracture reduction was maintained in 86.67 and 95% of the patients in groups A and B, respectively. Conclusions Both bridging and nonbridging external definitive dynamic fixation proved safe and reliable for the treatment of unstable DRFs in elderly patients with polytrauma. The grip strength results in both groups predicted the restoration of ability in elderly patients to perform activities of daily living independently.

5.
Med Biol Eng Comput ; 57(11): 2337-2346, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31506856

RESUMO

This study aims to analyze gait variability and stability of individuals with amputation walking on upward (8%), horizontal (0%), and downward (- 8%) inclines, by using linear and nonlinear descriptors. Trunk linear variability and gait spatiotemporal parameters were evaluated. Nonlinear variability (local dynamic stability-LDS), was estimated by the maximum Lyapunov exponent (λ) computed from a trunk marker velocity. The gait descriptors were compared among three distinct groups (N participants): unilateral transtibial amputees (TTA, N = 12); unilateral transfemoral amputees (TFA, N = 13); control group (CT, N = 15). For step width and support phase, the effect of inclination was greater for TFA group, especially in the DOWN condition. Linear variability was higher for amputees (TFA and TTA) especially in the UP condition in the medial-lateral and anterior-posterior directions. TTA and TFA groups presented greater λ values than CT group in medial-lateral direction indicating decreased LDS, but TFA group presented smaller λ values than TTA and CT groups in the V direction. Our findings showed that inclination introduced significant changes in the estimated parameters for all groups, with greater changes for amputee groups. Furthermore, the level of amputation directly affects the analyzed gait parameters being the TFA group the one which presents greater changes. Graphical abstract The objective of this study was to analyze gait variability of individuals with amputation walking on (A) upward (+ 8%), (B) horizontal (0%), and (C) downward (- 8%) inclines, by using linear and nonlinear biomechanical descriptors. Linear measures of variability, such trunk variability and gait spatiotemporal parameters were evaluated. Nonlinear variability was estimated by the exponent of divergence (maximum Lyapunov exponent) of the velocity of a marker fixed in the subject's trunk while walking on inclined surfaces.

6.
Braz J Cardiovasc Surg ; 34(3): 271-278, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31310464

RESUMO

OBJECTIVE: The goal of the present study was to compare the myocardial protection obtained with histidine-tryptophan-ketoglutarate (HTK) cardioplegic solution (Custodiol®) and with intermittent hypothermic blood solution. METHODS: Two homogenous groups of 25 children with acyanotic congenital heart disease who underwent total correction with mean aortic clamping time of 60 minutes were evaluated in this randomized study. Troponin and creatine kinase-MB curves, vasoactive-inotropic score, and left ventricular function were obtained by echocardiogram in each group. The values were correlated and presented through graphs and tables after adequate statistical treatment. RESULTS: It was observed that values of all the studied variables varied over time, but there was no difference between the groups. CONCLUSION: We conclude that in patients with acyanotic congenital cardiopathies submitted to total surgical correction, mean aortic clamping time around one hour, and cardiopulmonary bypass with moderate hypothermia, the HTK crystalloid cardioplegic solution offers the same myocardial protection as the cold-blood hyperkalemic cardioplegic solution analyzed, according to the variables considered in our study model.


Assuntos
Soluções Cardioplégicas/uso terapêutico , Cardiopatias Congênitas/cirurgia , Análise de Variância , Creatina Quinase Forma MB/análise , Método Duplo-Cego , Ecocardiografia , Feminino , Glucose/uso terapêutico , Cardiopatias Congênitas/fisiopatologia , Humanos , Lactente , Recém-Nascido , Masculino , Manitol/uso terapêutico , Duração da Cirurgia , Cloreto de Potássio/uso terapêutico , Procaína/uso terapêutico , Estudos Prospectivos , Substâncias Protetoras/uso terapêutico , Valores de Referência , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Fatores de Tempo , Resultado do Tratamento , Troponina/análise , Função Ventricular Esquerda
7.
Bioresour Technol ; 289: 121731, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323712

RESUMO

This study aimed to evaluate the promising feasibility of the hydrothermal pre-processing of eucalyptus wood and eucalyptus bark under organosolv and organic acid conditions to produce a highly concentrated cellulose feedstock. For that, particulate samples of both biomasses were heated in water solutions containing from 0 to 50%vol/vol of ethanol and from 0 to 50 mmol.L-1 of oxalic acid at temperatures between 140 and 180 °C. Significant differences on the thermal degradation profiles were observed for both biomasses indicating the partial hydrolysis converted them into a more homogeneous solid fraction with higher contents of cellulose. It was also observed a significant variation of the glycan content from approximately 39 to 76% for wood particles, whereas the variation for bark was from 32 to 50%. In general, the proposed pre-processing route was considered potentially feasible to concentrate the cellulose/glycan contents of eucalyptus biomasses for subsequent industrial utilization.


Assuntos
Eucalyptus , Biomassa , Celulose , Hidrólise , Madeira
8.
Rev. bras. cir. cardiovasc ; 34(3): 271-278, Jun. 2019. tab, graf
Artigo em Inglês | LILACS-Express | ID: biblio-1013463

RESUMO

Abstract Objective: The goal of the present study was to compare the myocardial protection obtained with histidine-tryptophan-ketoglutarate (HTK) cardioplegic solution (Custodiol®) and with intermittent hypothermic blood solution. Methods: Two homogenous groups of 25 children with acyanotic congenital heart disease who underwent total correction with mean aortic clamping time of 60 minutes were evaluated in this randomized study. Troponin and creatine kinase-MB curves, vasoactive-inotropic score, and left ventricular function were obtained by echocardiogram in each group. The values were correlated and presented through graphs and tables after adequate statistical treatment. Results: It was observed that values of all the studied variables varied over time, but there was no difference between the groups. Conclusion: We conclude that in patients with acyanotic congenital cardiopathies submitted to total surgical correction, mean aortic clamping time around one hour, and cardiopulmonary bypass with moderate hypothermia, the HTK crystalloid cardioplegic solution offers the same myocardial protection as the cold-blood hyperkalemic cardioplegic solution analyzed, according to the variables considered in our study model.

9.
Sci Rep ; 9(1): 7768, 2019 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-31123327

RESUMO

Pseudomonas syringae produces highly efficient biological ice nuclei (IN) that were proposed to influence precipitation by freezing water in clouds. This bacterium may be capable of dispersing through the atmosphere, having been reported in rain, snow, and cloud water samples. This study assesses its survival and maintenance of IN activity under stressing conditions present at high altitudes, such as UV radiation within clouds. Strains of the pathovars syringae and garcae were compared to Escherichia coli. While UV-C effectively inactivated these cells, the Pseudomonas were much more tolerant to UV-B. The P. syringae strains were also more resistant to radiation from a solar simulator, composed of UV-A and UV-B, while only one of them suffered a decline in IN activity at -5 °C after long exposures. Desiccation at different relative humidity values also affected the IN, but some activity at -5 °C was always maintained. The pathovar garcae tended to be more resistant than the pathovar syringae, particularly to desiccation, though its IN were found to be generally more sensitive. Compared to E. coli, the P. syringae strains appear to be better adapted to survival under conditions present at high altitudes and in clouds.

10.
Antibiotics (Basel) ; 8(1)2019 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-30884871

RESUMO

Orbignya speciosa (babassu) is an important palm tree in Brazil whose fixed almond oil is used in popular medicine and especially in food, in addition to being a research target for the manufacture of biofuels. The aim of this study was to evaluate the fixed almond oil physicochemical characterization and its antibacterial activity in isolation and in association with aminoglycosides against standard and multidrug-resistant bacteria. Analyses such as water content, pH, acidity, peroxide index, relative density, and refractive index indicate the stability and chemical quality of the oil. In the oil's GC/MS chemical composition analysis, a high saturated fatty acid (76.90%) content was observed. Lauric acid (56.28%) and oleic acid (23.10%) were the major oil components. In the antibacterial test, a more significant oil activity was observed against K. pneumoniae KP-ATCC 10031 (minimal inhibitory concentration (MIC) = 406.37 µg/mL) and Staphylococcus aureus ATCC 6538 (MIC = 812.75 µg/mL), but for the other strains-including standard and multi-resistant strains-the oil presented an MIC ≥ 1024 µg/mL. Furthermore, a synergistic effect was observed when the oil was associated with amikacin and gentamicin against S. aureus (SA-10) and an antagonistic effect was observed with amikacin against Escherichia coli. Data indicate the O. speciosa oil as a valuable nutritional source of lauric, oleic, and myristic fatty acids with an ability to modulate aminoglycoside activity.

11.
Sci Rep ; 9(1): 3977, 2019 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-30850657

RESUMO

Although marine plastic pollution has been the focus of several studies, there are still many gaps in our understanding of the concentrations, characteristics and impacts of plastics in the oceans. This study aimed to quantify and characterize plastic debris in oceanic surface waters of the Antarctic Peninsula. Sampling was done through surface trawls, and mean debris concentration was estimated at 1,794 items.km-2 with an average weight of 27.8 g.km-2. No statistical difference was found between the amount of mesoplastics (46%) and microplastics (54%). We found hard and flexible fragments, spheres and lines, in nine colors, composed mostly of polyurethane, polyamide, and polyethylene. An oceanographic dispersal model showed that, for at least seven years, sampled plastics likely did not originate from latitudes lower than 58°S. Analysis of epiplastic community diversity revealed bacteria, microalgae, and invertebrate groups adhered to debris. Paint fragments were present at all sampling stations and were approximately 30 times more abundant than plastics. Although paint particles were not included in plastic concentration estimates, we highlight that they could have similar impacts as marine plastics. We call for urgent action to avoid and mitigate plastic and paint fragment inputs to the Southern Ocean.

12.
Mar Pollut Bull ; 140: 536-548, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30803675

RESUMO

The ingestion of plastic marine litter (PML) by sea turtles is widespread and concerning, and the five species that occur in the southwestern Atlantic - green, loggerhead, olive ridley, leatherback and hawksbill - are vulnerable to this pollution. Here, we quantified and characterized PML ingested by these species in southern Brazil, and observed PML ingestion in 49 of 86 sampled individuals (~57.0%). Green turtles presented the highest rates and variety of ingested plastics, and such ingestion has been high at least since 1997. Omnivorous turtles presented higher PML ingestion than carnivorous ones. Loggerheads displayed a negative correlation between body size and number of ingested items. Green turtles ingested mostly flexible transparent and flexible/hard white plastics; loggerheads ate mainly flexible, hard and foam fragments, in white and black/brown colors. These results help us better understand PML ingestion by sea turtles, highlighting the seriousness of this threat and providing information for prevention and mitigation strategies.


Assuntos
Monitoramento Ambiental/métodos , Trato Gastrointestinal/química , Plásticos/análise , Resíduos Sólidos/análise , Tartarugas/metabolismo , Poluentes Químicos da Água/análise , Animais , Oceano Atlântico , Brasil , Ingestão de Alimentos , Plásticos/química
13.
Nat Prod Res ; : 1-5, 2019 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-30663376

RESUMO

In this study the physicochemical characterization of the pulp and almond fixed oil was carried out; their antibacterial activity and aminoglycoside antibiotic modifying action against standard and multiresistant Gram-positive and -negative bacteria were investigated using the broth microdilution assay. Physical properties such as moisture, pH, acidity, peroxide index, relative density and refractive index indicate stability and chemical quality of the oils. In the GC/MS chemical composition analysis, a high unsaturated fatty acid content and the presence of oleic and palmitic acids were observed in the oils. In the antibacterial assay, more significant results were obtained for Escherichia coli, while other standard and multi-resistant strains presented MIC values ≥ 1024 µg/mL. Furthermore, the fixed oils in association with antibiotics were able to significantly improve antibacterial activity against S. aureus with a reduction in MICs.

14.
Nucleic Acids Res ; 47(3): 1493-1504, 2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30476241

RESUMO

Trans-splicing of trypanosomatid polycistronic transcripts produces polyadenylated monocistronic mRNAs modified to form the 5' cap4 structure (m7Gpppm36,6,2'Apm2'Apm2'Cpm23,2'U). NMR and X-ray crystallography reveal that Leishmania has a unique type of N-terminally-extended cap-binding protein (eIF4E4) that binds via a PAM2 motif to PABP1. This relies on the interactions of a combination of polar and charged amino acid side-chains together with multiple hydrophobic interactions, and underpins a novel architecture in the Leishmania cap4-binding translation factor complex. Measurements using microscale thermophoresis, fluorescence anisotropy and surface plasmon resonance characterize the key interactions driving assembly of the Leishmania translation initiation complex. We demonstrate that this complex can accommodate Leishmania eIF4G3 which, unlike the standard eukaryotic initiation complex paradigm, binds tightly to eIF4E4, but not to PABP1. Thus, in Leishmania, the chain of interactions 5'cap4-eIF4E4-PABP1-poly(A) bridges the mRNA 5' and 3' ends. Exceptionally, therefore, by binding tightly to two protein ligands and to the mRNA 5' cap4 structure, the trypanosomatid N-terminally extended form of eIF4E acts as the core molecular scaffold for the mRNA-cap-binding complex. Finally, the eIF4E4 N-terminal extension is an intrinsically disordered region that transitions to a partly folded form upon binding to PABP1, whereby this interaction is not modulated by poly(A) binding to PABP1.


Assuntos
Fator de Iniciação 4E em Eucariotos/química , Leishmania/genética , Proteína I de Ligação a Poli(A)/química , Trans-Splicing/genética , Cristalografia por Raios X , Fator de Iniciação 4E em Eucariotos/genética , Ligantes , Espectroscopia de Ressonância Magnética , Complexos Multiproteicos/química , Complexos Multiproteicos/genética , Proteína I de Ligação a Poli(A)/genética , Proteínas de Ligação ao Cap de RNA/química , Proteínas de Ligação ao Cap de RNA/genética , RNA Mensageiro/química , RNA Mensageiro/genética
15.
Pest Manag Sci ; 75(5): 1295-1303, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30350447

RESUMO

BACKGROUND: Moniliophthora perniciosa (Stahel) Aime & Phillips-Mora is the causal agent of witches' broom disease (WBD) of cocoa (Theobroma cacao L.) and a threat to the chocolate industry. The membrane-bound enzyme alternative oxidase (AOX) is critical for M. perniciosa virulence and resistance to fungicides, which has also been observed in other phytopathogens. Notably AOX is an escape mechanism from strobilurins and other respiration inhibitors, making AOX a promising target for controlling WBD and other fungal diseases. RESULTS: We present the first study aimed at developing novel fungal AOX inhibitors. N-Phenylbenzamide (NPD) derivatives were screened in the model yeast Pichia pastoris through oxygen consumption and growth measurements. The most promising AOX inhibitor (NPD 7j-41) was further characterized and displayed better activity than the classical AOX inhibitor SHAM in vitro against filamentous fugal phytopathogens, such as M. perniciosa, Sclerotinia sclerotiorum and Venturia pirina. We demonstrate that 7j-41 inhibits M. perniciosa spore germination and prevents WBD symptom appearance in infected plants. Finally, a structural model of P. pastoris AOX was created and used in ligand structure-activity relationships analyses. CONCLUSION: We present novel fungal AOX inhibitors with antifungal activity against relevant phytopathogens. We envisage the development of novel antifungal agents to secure food production. © 2018 Society of Chemical Industry.


Assuntos
Agaricales/efeitos dos fármacos , Agaricales/fisiologia , Benzamidas/síntese química , Benzamidas/farmacologia , Cacau/microbiologia , Proteínas Mitocondriais/antagonistas & inibidores , Oxirredutases/antagonistas & inibidores , Doenças das Plantas/microbiologia , Proteínas de Plantas/antagonistas & inibidores , Antifúngicos/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Benzamidas/química , Técnicas de Química Sintética , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Relação Estrutura-Atividade
17.
Pathogens ; 7(4)2018 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-30544654

RESUMO

Mauritia flexuosa (buriti) is a typical Brazilian palm tree found in swampy regions with many plant forms. The fruit has various purposes with the pulps to the seeds being used for ice creams, sweets, creams, jellies, liqueurs, and vitamin production. A physicochemical characterization of the fixed pulp oil and its antibacterial and aminoglycoside antibiotic modifying activity against Gram-positive and Gram-negative multiresistant bacterial strains were performed using broth microdilution assays. Physical properties, such as moisture, pH, acidity, peroxide index, relative density, and refractive index, indicated oil stability and chemical quality. In the GC/MS chemical composition analysis, a high content of unsaturated fatty acids (89.81%) in relation to saturated fatty acids (10.19%) was observed. Oleic acid (89.81%) was the main fatty acid identified. In the antibacterial test, the fixed oil obtained the Minimum Inhibitory Concentration (MIC) ≥ 1024 µg/mL for all standard and multiresistant bacterial strains. The synergic effect of fixed pulp oil combined was observed only in Staphylococcus aureus SA⁻10, with an MIC reduction of the gentamicin and amikacin by 40.00% and 60.55%, respectively. The data indicates the M. flexuosa fixed oil as a valuable source of oleic acid and modulator of aminoglycoside activity.

18.
PeerJ ; 6: e5476, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30402343

RESUMO

Medicinal plants play a crucial role in the search for components that are capable of neutralizing the multiple mechanisms of fungal resistance. Psidium salutare (Kunth) O. Berg is a plant native to Brazil used as both food and traditional medicine to treat diseases and symptoms such as stomach ache and diarrhea, whose symptoms could be related to fungal infections from the genus Candida. The objective of this study was to investigate the influence of seasonal variability on the chemical composition of the Psidium salutare essential oil, its antifungal potential and its effect on the Candida albicans morphogenesis. The essential oils were collected in three different seasonal collection periods and isolated by the hydrodistillation process in a modified Clevenger apparatus with identification of the chemical composition determined by gas chromatography coupled to mass spectrometry (GC/MS). The antifungal assays were performed against Candida strains through the broth microdilution method to determine the minimum fungicidal concentration (MFC). Fungal growth was assessed by optical density reading and the Candida albicans dimorphic effect was evaluated by optical microscopy in microculture chambers. The chemical profile of the essential oils identified 40 substances in the different collection periods with γ-terpinene being the predominant constituent. The antifungal activity revealed an action against the C. albicans, C. krusei and C. tropicalis strains with an IC50 ranging from 345.5 to 2,754.2 µg/mL and a MFC higher than 1,024 µg/mL. When combined with essential oils at sub-inhibitory concentrations (MIC/16), fluconazole had its potentiated effect, i.e. a synergistic effect was observed in the combination of fluconazole with P.salutare oil against all Candida strains; however, for C. albicans, its effect was reinforced by the natural product in all the collection periods. The results show that the Psidium salutare oil affected the dimorphic transition capacity, significantly reducing the formation of hyphae and pseudohyphae in increasing concentrations. The results show that P. salutare oil exhibits a significant antifungal activity against three Candida species and that it can act in synergy with fluconazole. These results support the notion that this plant may have a potential use in pharmaceutical and preservative products.

19.
Microb Pathog ; 125: 144-149, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30219391

RESUMO

Vanillosmopsis arborea Barker (Asteraceae), commonly known as "candeeiro" is an endemic tree to the Caatinga biome, in northeast Brazil. The major component of its essential oil is α-bisabolol, a monocyclic sesquiterpene alcohol with several biological activities reported. In this study, the antimicrobial activity of the essential oil of V. arborea was investigated in comparison with its major component α-bisabol. The antimicrobial activity was performed against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 12692, Candida albicans (CA) INCQS 40006, Candida krusei (CK) INCQS 40095, Candida tropicalis (CT) INCQS 40042, and multiresistant bacterial strains Staphylococcus aureus 03 and Escherichia coli 08 by the microdilution method and direct contact modulation. The results showed that all strains were sensitive to the samples, except E. coli against the essential oil. Both the essential oil and the α-bisabolol had a synergistic effect against all strains, except for ampicillin against S. aureus 03, which did not show any modifications when combined with the oil. These data show the potential of V. arborea essential oil as an antibiotic modulator as well as a source of bioactive compounds with potential for the development of antimicrobial drugs as well as adjuvant to therapy against these pathogens.


Assuntos
Anti-Infecciosos/farmacologia , Asteraceae/química , Candida/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Óleos Voláteis/farmacologia , Sesquiterpenos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Anti-Infecciosos/isolamento & purificação , Brasil , Sinergismo Farmacológico , Testes de Sensibilidade Microbiana , Óleos Voláteis/isolamento & purificação , Sesquiterpenos/isolamento & purificação
20.
Electrophoresis ; 39(22): 2898-2905, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30229957

RESUMO

The importance of microorganisms and biotechnology in space exploration and future planets colonization has been discussed in the literature. Meteorites are interesting samples to study microbe-mineral interaction focused on space exploration. The chemolithotropic bacterium Acidithiobacillus ferrooxidans has been used as model to understand the iron and sulfur oxidation. In this work, capillary electrophoresis with capacitively coupled contactless conductivity detection and UV detection was used to monitor bacterial growth in a meteorite simulant by measuring the conversion of Fe2+ into Fe+3 . The effect of Co2+ and Ni2+ (metals also found in meteorites) on the bacterial growth was also evaluated. The presented method allowed the analyses of all metals in a single run (less than 8 min). The background electrolyte was composted of 10 mmol/L α-hydroxyisobutyric acid/Histidine. For comparison purpose, the samples were also analyzed by UV-Vis spectrophotometry. The Fe2+ conversion into Fe3+ by A. ferrooxidans was observed up to 36 h with the growth rate constant of 0.19/h and 0.21/h in Tuovinen and Kelly (T&K) and in meteorite simulant media, respectively. The developed method presents favorable prospect to monitor the growth of other chemolithotropic microorganisms for biotechnology applications.


Assuntos
Acidithiobacillus/metabolismo , Eletroforese Capilar/métodos , Meteoroides , Acidithiobacillus/química , Crescimento Quimioautotrófico , Ferro/análise , Ferro/metabolismo , Oxirredução , Reprodutibilidade dos Testes , Espectrofotometria Ultravioleta , Sulfetos/análise , Sulfetos/metabolismo
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