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1.
Chemosphere ; 249: 126420, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32208215

RESUMO

Since the DeepWater Horizon oil spill and the use at 1450 m depth of dispersant as a technical response, the need of relevant ecotoxicological data on deep-sea ecosystems becomes crucial. In this context, this study focused on the effect of high hydrostatic pressure (10.1 MPa) on turbot hepatocytes isolated from fish exposed either to chemically dispersed oil, mechanically dispersed oil or dispersant alone. Potential combined effects of oil/dispersant and hydrostatic pressure, were assessed on cell mortality (total cell death, necrosis and apoptosis), cell viability and on hepatocyte oxygen consumption (MO2). No change in cell mortality was observed in any of the experimental conditions, whereas, the results of cell viability showed a strong and significant increase in the two oil groups independently of the pressure exposure. Finally, oil exposure and hydrostatic pressure have additive effects on oxygen consumption at a cellular level. Presence of dispersant prevent any MO2 increase in our experimental conditions. These mechanistic effects leading to this increased energetic demand and its eventual inhibition by dispersant must be investigated in further experiments.


Assuntos
Linguados/fisiologia , Poluição por Petróleo , Petróleo/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Ecossistema , Ecotoxicologia , Hepatócitos , Pressão Hidrostática , Alimentos Marinhos , Poluentes Químicos da Água/análise
2.
Food Chem ; 310: 125699, 2020 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31810727

RESUMO

The capacity of high-fiber foods to sequester BS during digestion is considered a mechanism to lower serum-cholesterol. We investigated the effect of hydrothermal (HT) and high-hydrostatic-pressure (HHP) on the bile salt (BS)-binding ability of dry beans, and how this relates to changes in bean microstructure, fiber content (insoluble-IDF/soluble-SDF), and viscosity. HT and HHP-600 MPa led to significant IDF reduction, including resistant starch (RS), whereas 150-450 MPa significantly increased RS, without modifying IDF/SDF content. Microscopy analysis showed that heating disrupted the bean cell wall integrity, protein matrix and starch granules more severely than 600 MPa; however, tightly-packed complexes of globular starch granules-protein-cell wall fiber formed at HHP ≤ 450 MPa. While HT significantly reduced BS-binding efficiency despite no viscosity change, HHP-treatments maintained or enhanced BS-retention. 600 MPa-treatment induced the maximum BS-binding ability and viscosity. These results demonstrate that BS-binding by beans is not solely based on their fiber content or viscosity, but is influenced by additional microstructural factors.


Assuntos
Ácidos e Sais Biliares/metabolismo , Fibras na Dieta , Manipulação de Alimentos/métodos , Phaseolus/química , Phaseolus/ultraestrutura , Parede Celular/química , Parede Celular/ultraestrutura , Fibras na Dieta/análise , Pressão Hidrostática , Phaseolus/metabolismo , Proteínas de Vegetais Comestíveis/química , Solubilidade , Amido/química , Viscosidade
3.
Chem Asian J ; 15(2): 214-230, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31714665

RESUMO

Catalysis by nucleic acids is indispensable for extant cellular life, and it is widely accepted that nucleic acid enzymes were crucial for the emergence of primitive life 3.5-4 billion years ago. However, geochemical conditions on early Earth must have differed greatly from the constant internal milieus of today's cells. In order to explore plausible scenarios for early molecular evolution, it is therefore essential to understand how different physicochemical parameters, such as temperature, pH, and ionic composition, influence nucleic acid catalysis and to explore to what extent nucleic acid enzymes can adapt to non-physiological conditions. In this article, we give an overview of the research on catalysis of nucleic acids, in particular catalytic RNAs (ribozymes) and DNAs (deoxyribozymes), under extreme and/or unusual conditions that may relate to prebiotic environments.


Assuntos
DNA Catalítico/química , RNA Catalítico/química , Sequência de Bases , Catálise , DNA Catalítico/efeitos da radiação , Concentração de Íons de Hidrogênio , Pressão Hidrostática , Metais/química , Origem da Vida , RNA Catalítico/efeitos da radiação , Temperatura , Raios Ultravioleta
4.
Food Microbiol ; 86: 103315, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31703881

RESUMO

Non-thermal food processing and replacement of chemical additives by natural antimicrobials are promising trends in the food industry. The objective of the present work was to evaluate the effect of a process which combines mild high hydrostatic pressure - HHP (200 and 300 MPa, 5 min, 10 °C), phage Listex™ P100 and the bacteriocin pediocin PA-1 as a new non-thermal process for destruction of Listeria monocytogenes (104 CFU mL-1 or 107 CFU mL-1) in milk. For inoculum levels of 104 CFU mL-1, HHP combined with phage P100 eliminated L. monocytogenes immediately after pressurization. When L. monocytogenes was inoculated at levels of 107 CFU mL-1, a synergistic effect between phage P100, pediocin PA-1 and HHP (300 MPa) on the inactivation of L. monocytogenes was observed during storage of milk at 4 °C. For non-pressure treated samples inoculated with phage or pediocin or both, L. monocytogenes counts decreased immediately after biocontrol application, but regrowth was observed in a few samples during storage. Phage particles were stable during refrigerated storage for seven days while pediocin PA-1 remained stable only during three days. Further studies will have to be performed to validate the findings of this work in specific applications (e.g. production of raw milk cheese).


Assuntos
Bacteriófagos/fisiologia , Conservação de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/virologia , Leite/microbiologia , Pediocinas/farmacologia , Animais , Bovinos , Contagem de Colônia Microbiana , Conservação de Alimentos/instrumentação , Pressão Hidrostática , Listeria monocytogenes/química , Listeria monocytogenes/crescimento & desenvolvimento
5.
Proc Natl Acad Sci U S A ; 117(3): 1772-1778, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31879350

RESUMO

Fluid fills intracellular, extracellular, and capillary spaces within muscle. During normal physiological activity, intramuscular fluid pressures develop as muscle exerts a portion of its developed force internally. These pressures, typically ranging between 10 and 250 mmHg, are rarely considered in mechanical models of muscle but have the potential to affect performance by influencing force and work produced during contraction. Here, we test a model of muscle structure in which intramuscular pressure directly influences contractile force. Using a pneumatic cuff, we pressurize muscle midcontraction at 260 mmHg and report the effect on isometric force. Pressurization reduced isometric force at short muscle lengths (e.g., -11.87% of P0 at 0.9 L0), increased force at long lengths (e.g., +3.08% of P0 at 1.25 L0), but had no effect at intermediate muscle lengths ∼1.1-1.15 L0 This variable response to pressurization was qualitatively mimicked by simple physical models of muscle morphology that displayed negative, positive, or neutral responses to pressurization depending on the orientation of reinforcing fibers representing extracellular matrix collagen. These findings show that pressurization can have immediate, significant effects on muscle contractile force and suggest that forces transmitted to the extracellular matrix via pressurized fluid may be important, but largely unacknowledged, determinants of muscle performance in vivo.


Assuntos
Fenômenos Biomecânicos , Líquidos Corporais/fisiologia , Pressão Hidrostática , Contração Muscular/fisiologia , Animais , Colágeno , Matriz Extracelular , Músculos Isquiossurais/fisiologia , Contração Isométrica , Modelos Biológicos , Músculo Esquelético/fisiologia , Rana catesbeiana
6.
Life Sci ; 242: 117209, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31870776

RESUMO

AIMS: Hypertension is an independent risk factor for atrial fibrillation (AF). However, the direct effect of hydrostatic pressure on atrial electrical remodeling is unclear. The present study investigated whether hydrostatic pressure is responsible for atrial electrical remodeling and addressed a potential role of inflammation in this pathology. MAIN METHODS: Whole-cell patch-clamp recordings and biochemical assays were used to study the regulation and expression of ion channels in left atrial appendages in patients with AF, spontaneously hypertensive rats (SHRs), and atrium-derived cells (HL-1 cells) exposed to standard (0 mmHg) and elevated (20, 40 mmHg) hydrostatic pressure. KEY FINDINGS: Both TNF-α and MIF were highly expressed in patients with AF and SHRs. AF inducibility in SHRs was higher after atrial burst pacing, accompanied by a decrease in the L-type calcium current (ICa,L), an increase in the transient outward K+ current (Ito) and ultra-rapid delayed rectifier K+ current (IKur), and a shortened action potential duration (APD), which could be inhibited by atorvastatin. Furthermore, exposure to elevated pressure was associated with electrical remodeling of the HL-1 cells. The peak current density of ICa,L was reduced, while Ito and IKur were increased. Moreover, the expression levels of Kv4.3, Kv1.5, TNF-α, and MIF were upregulated, while the expression of Cav1.2 was downregulated in HL-1 cells after treatment with high hydrostatic pressure (40 mmHg). Atorvastatin alleviated the electrical remodeling and increased inflammatory markers in HL-1 cells induced by high hydrostatic pressure. SIGNIFICANCE: Elevated hydrostatic pressure led to atrial electrical remodeling and increased AF susceptibility by upregulating inflammation.


Assuntos
Remodelamento Atrial , Citocinas/metabolismo , Pressão Hidrostática/efeitos adversos , Adulto , Animais , Western Blotting , Feminino , Átrios do Coração/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Miócitos Cardíacos/metabolismo , Técnicas de Patch-Clamp , Ratos Endogâmicos SHR , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Regulação para Cima
7.
Braz. dent. sci ; 23(1): 1-7, 2020. tab
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1049603

RESUMO

Objective: Evaluate the microtensile bond strength (µTBS) in different dentin thicknesses, under simulated pulpal pressure (SPP), submitted to an adhesive technique using laser irradiation. Material and methods: Forty sound human molars were sectioned and randomly divided into two groups (n=20): Group 1 ­ 1 mm of dentin thickness; Group 2 ­ 2 mm of dentin thickness. Each group was divided into two subgroups (n=10): Subgroup A ­ Absence of SPP; Subgroup P ­ Presence of SPP (15 cm H2 O). The samples were sequentially treated with: 37% phosphoric acid, adhesive system (Adper Single Bond 2), Nd:YAG laser irradiation (60 s, 1064 nm, 10 Hz) using 60 and 100 mJ/pulse energy parameters and photopolymerization (10 s). A composite resin block (Filtek Z350) was built up onto the irradiated area. After 30 days stored in water, the samples were sectioned and submitted to microtensile test (10 kgf load cell, 0.5mm/min). Data were analyzed by twoway ANOVA and Tukey tests. Results: Two-way ANOVA revealed no significant differences for SPP on bond strength. The laser energy parameters indicated that 100 mJ showed greater µTBS means compared to the group irradiated with 60 mJ. The presence of SPP reduced the mean µTBS values. Conclusions: Simulated pulpal pressure did not affect the µTBS using 60 mJ of laser energy parameter. At 100 mJ, the presence of SPP negatively influenced the bond strength, regardless of dentin thickness (AU)


Objetivo: O objetivo deste estudo foi avaliar a resistência adesiva (RA) em diferentes espessuras de dentina, associada à pressão pulpar simulada (PPS), quando submetidos à técnica adesiva por irradiação laser. Material e Métodos: Quarenta molares humanos hígidos foram seccionados e divididos aleatoriamente em dois grupos (n=20): Grupo 1 ­ 1 mm de espessura de dentina; Grupo 2 ­ 2 mm de espessura de dentina. As amostras foram divididas em 2 subgrupos (n=10): Subgrupo A ­ ausência de PPS; Subgrupo P ­ presença de PPS (15 cm de H2 O). As amostras foram tratadas seqüencialmente com: ácido fosfórico 37%, sistema adesivo (Adper Single Bond 2), irradiação com Nd:YAG laser (60 s, 1064 nm, 10 Hz) nos parâmetros de energia de 60 e 100 mJ/pulso e fotopolimerização (10 s). Um bloco de resina composta (Filtek Z350, 3M ESPE) foi confeccionado sobre a área irradiada. Após 30 dias armazenados em água, os espécimes foram seccionados e submetidos ao teste de microtração (carga de 10 kgf, 0.5mm/min). Os dados foram analisados pelos testes ANOVA sob 2 fatores e Tukey (p<0.05). Resultados: ANOVA mostrou que não houve diferenças significativas para PPS na RA. Para os parâmetros de energia do laser, 100 mJ apresentou maiores médias de RA quando comparado ao grupo irradiado à 60 mJ. A presença da PPS reduziu as médias de RA. Conclusão: Pressão pulpar simulada não afetou os valores de resistência adesiva para o grupo irradiado com 60 mJ. Para 100 mJ, a presença da pressão pulpar influenciou negativamente na resistência adesiva, independente das espessuras de dentina.(AU)


Assuntos
Resinas Compostas , Dentina , Pressão Hidrostática , Lasers
8.
Food Chem ; 309: 125794, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31784074

RESUMO

Jabuticaba is a Brazilian berry rich in phenolic compounds (PC), which are mainly concentrated in its peel and seed (JPS), fractions that are not usually consumed. Thus, to develop a powder with potential functional properties, we investigated the effect of pressurization and dehydration methods on the chemical composition of JPS, with emphasis on PC. JPS showed a very diverse PC profile, including phenolic acids, flavonoids, ellagitannins and proanthocyanidins. Contrary to our hypothesis, pressurization was ineffective in increasing total PC contents of JPS. Freeze-drying and oven-drying at 75 °C yielded powders with similar total PC contents, but with distinct profile, the former richer in anthocyanins and the latter in ellagitannins. Considering that both dehydration methods produced a jabuticaba powder rich in PC, and that freeze-drying is a higher cost method, the choice between these drying methods depends on the purpose of the final product.


Assuntos
Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Myrtaceae/química , Fenóis/química , Antocianinas/química , Antioxidantes/química , Liofilização , Frutas/química , Frutas/metabolismo , Taninos Hidrolisáveis/química , Pressão Hidrostática , Myrtaceae/metabolismo , Fenóis/análise , Extratos Vegetais/química , Sementes/química , Sementes/metabolismo
9.
Elife ; 82019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31571582

RESUMO

Animals make organs of precise size, shape, and symmetry but how developing embryos do this is largely unknown. Here, we combine quantitative imaging, physical theory, and physiological measurement of hydrostatic pressure and fluid transport in zebrafish to study size control of the developing inner ear. We find that fluid accumulation creates hydrostatic pressure in the lumen leading to stress in the epithelium and expansion of the otic vesicle. Pressure, in turn, inhibits fluid transport into the lumen. This negative feedback loop between pressure and transport allows the otic vesicle to change growth rate to control natural or experimentally-induced size variation. Spatiotemporal patterning of contractility modulates pressure-driven strain for regional tissue thinning. Our work connects molecular-driven mechanisms, such as osmotic pressure driven strain and actomyosin tension, to the regulation of tissue morphogenesis via hydraulic feedback to ensure robust control of organ size. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).


Assuntos
Líquidos Corporais , Orelha Interna/embriologia , Retroalimentação , Pressão Hidrostática , Animais , Pressão Osmótica , Peixe-Zebra
10.
Invest Ophthalmol Vis Sci ; 60(13): 4416-4424, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31639828

RESUMO

Purpose: Lenses have an intracellular hydrostatic pressure gradient to drive fluid from central fiber cells to surface epithelial cells. Pressure is regulated by a feedback control system that relies on transient receptor potential vanilloid (TRPV)1 and TRPV4 channels. The ciliary muscle transmits tension to the lens through the zonules of Zinn. Here, we have examined if ciliary muscle tension influenced the lens intracellular hydrostatic pressure gradient. Methods: We measured the ciliary body position and intracellular hydrostatic pressures in mouse lenses while pharmacologically causing relaxation or contraction of the ciliary muscle. We also used inhibitors of TRPV1 and TRPV4, in addition to phosphoinositide 3-kinase (PI3K) p110α knockout mice and immunostaining of phosphorylated protein kinase B (Akt), to determine how changes in ciliary muscle tension resulted in altered hydrostatic pressure. Results: Ciliary muscle relaxation increased the distance between the ciliary body and the lens and caused a decrease in intracellular hydrostatic pressure that was dependent on intact zonules and could be blocked by inhibition of TRPV4. Ciliary contraction moved the ciliary body toward the lens and caused an increase in intracellular hydrostatic pressure and Akt phosphorylation that required intact zonules and was blocked by either inhibition of TRPV1 or genetic deletion of the p110α catalytic subunit of PI3K. Conclusions: These results show that the hydrostatic pressure gradient within the lens was influenced by the tension exerted on the lens by the ciliary muscle through the zonules of Zinn. Modulation of the gradient of intracellular hydrostatic pressure in the lens could alter the water content, and the gradient of refractive index.


Assuntos
Corpo Ciliar/metabolismo , Cristalino/metabolismo , Ligamentos/metabolismo , Músculo Liso/metabolismo , Canais de Cátion TRPV/metabolismo , Animais , Técnica Indireta de Fluorescência para Anticorpo , Pressão Hidrostática , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Contração Muscular/efeitos dos fármacos , Relaxamento Muscular/efeitos dos fármacos , Midriáticos/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Pilocarpina/farmacologia , Canais de Cátion TRPV/antagonistas & inibidores , Tropicamida/farmacologia
11.
Comput Methods Biomech Biomed Engin ; 22(16): 1294-1302, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31553278

RESUMO

Orthodontic tooth movement is mainly regulated by the biomechanical responses of loaded periodontal ligament (PDL). We investigated the effective intervals of orthodontic force in pure maxillary canine intrusion and extrusion referring to PDL hydrostatic stress and logarithmic strain. Finite element analysis (FEA) models, including a maxillary canine, PDL and alveolar bone, were constructed based on computed tomography (CT) images of a patient. The material properties of alveolar bone were non-uniformly defined using HU values of CT images; PDL was assumed to be a hyperelastic-viscoelastic material. The compressive stress and tensile stress ranging from 0.47 to 12.8 kPa and 18.8 to 51.2 kPa, respectively, were identified as effective for tooth movement; a strain 0.24% was identified as the lower limit of effective strain. The stress/strain distributions within PDL were acquired in canine intrusion and extrusion using FEA; root apex was the main force-bearing area in intrusion-extrusion movements and was more prone to resorption. Owing to the distinction of PDL biomechanical responses to compression and tension, the effective interval of orthodontic force was substantially lower in canine intrusion (80-90 g) than in canine extrusion (230-260 g). A larger magnitude of force remained applicable in canine extrusion. This study revised and complemented orthodontic biomechanical behaviours of tooth movement with intrusive-extrusive force and could further help optimize orthodontic treatment.


Assuntos
Dente Canino/fisiologia , Análise de Elementos Finitos , Maxila/fisiologia , Processo Alveolar/fisiologia , Fenômenos Biomecânicos , Simulação por Computador , Humanos , Pressão Hidrostática , Modelos Biológicos , Ligamento Periodontal/fisiologia , Estresse Mecânico , Técnicas de Movimentação Dentária
12.
Int J Food Microbiol ; 309: 108330, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31493566

RESUMO

A probabilistic model based on logistic regression was developed for a target log reduction of microorganisms inactivated by high hydrostatic pressure. Published inactivation data of Salmonella Typhimurium in broth for 4 and 5 log reductions, and Escherichia coli in buffer and carrot juice for 5 log reduction were used. The probabilities of achieving 4 or 5 log reductions for S. Typhimurium in broth and 5 log reduction for E. coli in buffer and carrot juice could be calculated at different pressure, temperature and time levels. The fitted interfaces of achieving/not achieving the target log reduction were consistent with the experimental data. Although the reliability of the predictions of the developed models could be questioned due to strain variation and different food matrix, a validation study has demonstrated that the developed models could be used to predict the target log reduction of these microorganisms at different pressure, temperature and time levels. This study has indicated that the probabilistic modeling for target log reductions can be useful tool for HHP inactivation of microorganisms, but further studies could be performed with several other factors such as pH and water activity of the food, concentration of certain additives as well as initial number of bacteria present in the food.


Assuntos
Escherichia coli/isolamento & purificação , Microbiologia de Alimentos/métodos , Conservação de Alimentos/métodos , Pressão Hidrostática , Salmonella typhimurium/isolamento & purificação , Contagem de Colônia Microbiana , Reprodutibilidade dos Testes , Temperatura
13.
Biocontrol Sci ; 24(3): 167-172, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31527348

RESUMO

Spores of Bacillus subtilis suspended in water or aqueous solution of NaCl, CaCl2, sodium lactate, or calcium lactate at pH 4 - 7 was subjected to spore inactivation by simultaneous combination of medium high hydrostatic pressure (MHHP; 100 MPa) treatment for germination and medium high temperature (MHT; 65℃) treatment for pasteurization of germinated vegetative cells. The spores at pH 4 in NaCl solution and those at pH 5 and 6 in Na lactate solutions were less killed than in water by MHHP+MHT treatment. Spore inactivation was promoted by calcium ion in NaCl solution at pH 4 and in Na lactate solutions at pH 5 and pH 6, while it was more suppressed at pH 5 and pH 6 in Na lactate solutions than at pH 4 in NaCl solution. The spores treated by MHHP+MHT in NaCl or Na lactate solution at pH 4 were further killed by subsequent MHT treatment.


Assuntos
Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Íons/metabolismo , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/crescimento & desenvolvimento , Pressão Hidrostática , Temperatura , Microbiologia da Água
14.
J Sci Food Agric ; 99(15): 6806-6813, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31368526

RESUMO

BACKGROUND: Enzymatic hydrolysis and high hydrostatic pressure (HHP) are common processing techniques in the extraction of active compounds from food materials. The aim of this study was to investigate the effects of enzymatic hydrolysis combined with HHP treatments on ginsenoside metabolites in red ginseng. RESULTS: The yield and changes in the levels of polyphenol and ginsenoside were measured in red ginseng treated with commercial enzymes such as Ultraflo L, Viscozyme, Cytolase PCL5, Rapidase and Econase E at atmospheric pressure (0.1 MPa), 50 MPa, and 100 MPa. ß-Glucosidase activity of Cytolase was the highest at 4258.2 mg-1 , whereas Viscozyme showed the lowest activity at 10.6 mg-1 . Pressure of 100 MPa did not affect the stability or the activity of the ß-glucosidase. Treatment of red ginseng with Cytolase and Econase at 100 MPa significantly increased the dry weight and polyphenol content of red ginseng, compared with treatments at 0.1 MPa and 50 MPa (P < 0.05). The amounts of ginsenoside and ginsenoside metabolites derived from red ginseng processed using Cytolase were higher than those derived from red ginseng treated with the other enzymes. Treatment with Cytolase also significantly increased the skin and intestinal permeability of red ginseng-derived polyphenols. CONCLUSION: Cytolase could be useful as an enzymatic treatment to enhance the yield of bioactive compounds from ginseng under HHP. In addition, ginsenoside metabolites obtained by Cytolase hydrolysis combined with HHP are functional substances with increased intestinal and skin permeability. © 2019 Society of Chemical Industry.


Assuntos
Enzimas/química , Manipulação de Alimentos/métodos , Ginsenosídeos/química , Ginsenosídeos/metabolismo , Panax/química , Extratos Vegetais/química , Extratos Vegetais/metabolismo , Animais , Biocatálise , Hidrólise , Pressão Hidrostática , Mucosa Intestinal/metabolismo , Masculino , Panax/metabolismo , Ratos , Ratos Sprague-Dawley , Pele/metabolismo
15.
Food Microbiol ; 84: 103246, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421746

RESUMO

Traditional and novel technologies for food preservation are being investigated to obtain safer products and fulfil consumer demands for less processed foods. These technologies inactivate microorganisms present in foods through their action on different cellular targets, but the final cause of cell loss of viability often remains not well characterized. The main objective of this work was to study and compare cellular events that could play a role on E. coli inactivation upon exposure to treatments with technologies of different nature. E. coli cells were exposed to heat, high hydrostatic pressure (HHP), pulsed electric fields (PEF) and acid treatments, and the occurrence of several alterations, including presence of sublethal injury, membrane permeabilization, increased levels of reactive oxygen species (ROS), DNA damage and protein damage were studied. Results reflected differences among the relevance of the several cellular events depending on the agent applied. Sublethally injured cells appeared after all the treatments. Cells consistently recovered in a higher percentage in non-selective medium, particularly in minimal medium, as compared to selective medium; however this effect was less relevant in PEF-treated cells. Increased levels of ROS were detected inside cells after all the treatments, although their order of appearance and relationship with membrane permeabilization varied depending on the technology. A high degree of membrane permeabilization was observed in PEF treated cells, DNA damage appeared as an important target in acid treatment, and protein damage, in HHP treated cells. Results obtained help to understand the mode of action of food preservation technologies on bacterial cells.


Assuntos
Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Ácidos , Contagem de Colônia Microbiana , Dano ao DNA , Eletricidade , Temperatura Alta , Concentração de Íons de Hidrogênio , Pressão Hidrostática
16.
Elife ; 82019 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-31393262

RESUMO

Many viruses previously have been shown to have pressurized genomes inside their viral protein shell, termed the capsid. This pressure results from the tight confinement of negatively charged viral nucleic acids inside the capsid. However, the relevance of capsid pressure to viral infection has not been demonstrated. In this work, we show that the internal DNA pressure of tens of atmospheres inside a herpesvirus capsid powers ejection of the viral genome into a host cell nucleus. To our knowledge, this provides the first demonstration of a pressure-dependent mechanism of viral genome penetration into a host nucleus, leading to infection of eukaryotic cells.


Assuntos
Capsídeo/metabolismo , Núcleo Celular/virologia , DNA Viral/metabolismo , Células Eucarióticas/virologia , Herpesvirus Humano 1/fisiologia , Pressão Hidrostática , Internalização do Vírus , Animais , Linhagem Celular
17.
J Microbiol Biotechnol ; 29(8): 1240-1247, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31370118

RESUMO

This study was conducted to examine the inactivation effect of the combined treatment of high hydrostatic pressure (HHP; 400 MPa for 1, 3, and 5 min) and cationic surfactant washing (0.05% benzethonium chloride, BEC) against Listeria monocytogenes inoculated on fresh-cut broccoli (FCB). Washing with BEC at concentrations exceeding 0.05% resulted in 2.3 logreduction of L. monocytogenes counts on FCB, whereas HHP treatment had approximately 5.5- 5.6 log-reductions regardless of the treatment time. Scanning electron microscopy corroborated microbial enumeration, revealing that the combined treatment was more effective in removing L. monocytogenes from FCB than individual treatment with HHP or BEC. Color and total glucosinolate content were maintained after the combined treatment, although the hardness of the FCB slightly decreased. The results clearly suggest that the combined treatment of HHP and BEC washing has potential value as a new sanitization method to improve the microbial safety of FCB.


Assuntos
Brassica/microbiologia , Conservação de Alimentos/métodos , Listeria monocytogenes/efeitos dos fármacos , Tensoativos/farmacologia , Benzetônio/farmacologia , Contagem de Colônia Microbiana , Cor , Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos , Qualidade dos Alimentos , Inocuidade dos Alimentos , Pressão Hidrostática , Listeria monocytogenes/crescimento & desenvolvimento
18.
Med Hypotheses ; 130: 109293, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31383334

RESUMO

Tarlov cysts (TCs) consist of dilated nerve root sheaths filled with cerebrospinal fluid (CSF) and are most frequently found in the sacrum. It is estimated that 25% of detected TCs cause chronic pain and intestinal and urogenital symptoms due to compression of the sacral nerve root fibers inside the TC. Unfortunately, symptomatic TCs are frequently overlooked. It is assumed that TCs result from pathologically increased hydrostatic pressure (HP) in the dural sac that forces CSF into the nerve root sheaths. We hypothesize that in patients with TCs, increased spinal hydrostatic pressure is always associated with increased intracranial pressure. This hypothesis of increased cerebrospinal pressure might explain why patients with sacral TCs frequently report distant symptoms, such as headaches and pain in the neck and arms. In this paper, we describe a case report that provides evidence for this hypothesis. A 30-year-old man presented for the first time in our clinic complaining of lower back, leg, thoracic, neck, and arm pain; headaches; and bladder, bowel, and sphincter symptoms. He was born prematurely and suffered cerebral intraventricular bleeding followed by progressive hydrocephalus. Progression was stabilized with acetazolamide and lumbar punctures. At 19 years of age, his head circumference had further increased and he reported back pain and headaches. Fundoscopy showed no papilledema, and lumbar puncture for CSF evacuation improved the headaches and back pain. The former medical team chose not to insert a ventriculo-external shunt. Brain magnetic resonance imaging (MRI) showed significant dilation of all the ventricles. No CSF flow obstruction between the ventricles was observed. Surprisingly, MRI of the lumbar and sacral spine showed multiple large TCs. This case report indicates that hydrocephalus with a patent aqueduct may be associated with TCs because the increased intracranial pressure is transferred to the spinal canal. While increased intracranial pressure causes dilation of the ventricles, the associated increased spinal pressure may cause dilation of multiple spinal nerve root sheaths to form TCs. Furthermore, while the increased volume of the ventricles gradually compresses the neurons and axons of the brain against the bony skull, simultaneously, the increased pressure inside the nerve sheaths may also gradually compress the neurons and axons located inside the dorsal root ganglia and spinal nerves, resulting in neuropathic pain, sensory abnormalities, and neurogenic bladder and bowel symptoms. Hydrocephalus patients reporting neuropathic pain should be screened for the presence of TCs.


Assuntos
Encéfalo/diagnóstico por imagem , Hidrocefalia/complicações , Cistos de Tarlov/complicações , Adulto , Axônios/metabolismo , Dor Crônica , Progressão da Doença , Humanos , Hidrocefalia/fisiopatologia , Pressão Hidrostática , Hipertensão Intracraniana/fisiopatologia , Pressão Intracraniana , Vértebras Lombares/diagnóstico por imagem , Masculino , Neurônios/metabolismo , Sacro/diagnóstico por imagem , Cistos de Tarlov/fisiopatologia
19.
Med Hypotheses ; 130: 109271, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31383335

RESUMO

Recent clinical studies show a positive correlation between elevated plasma TMAO and increased cardiovascular risk. However, the mechanism of the increase and biological effects of TMAO in the circulatory system are obscure. Plasma TMAO level depends mostly on the following three factors. First, the liver produces TMAO from TMA, a gut bacteria metabolite of dietary choline and carnitine. Second, plasma TMAO increases after ingestion of dietary TMAO from fish and seafood. Finally, plasma TMAO depends on TMAO and TMA excretion by the kidneys. Ample evidence highlights protective functions of TMAO, including the stabilization of proteins and cells exposed to hydrostatic and osmotic stresses, for example in fish exposed to hydrostatic stress (deep water) and osmotic stress (salty water). Osmotic stress and hydrostatic stresses are augmented in cardiovascular diseases such as hypertension. In hypertensive subjects a diastole-systole change in hydrostatic pressure in the heart may exceed 220 mmHg with a frequency of 60-220/min. This produces environment in which hydrostatic pressure changes over 100,000 times per 24 h. Furthermore, cardiovascular diseases are associated with disturbances in water-electrolyte balance which produce changes in plasma osmolarity. Perhaps, the increase in plasma TMAO in cardiovascular diseases is analogous to increased level of plasma natriuretic peptide B, which is both a cardiovascular risk marker and a compensatory response producing beneficial effects for pressure/volume overloaded heart. In this regard, there is some evidence that a moderate increase in plasma TMAO due to TMAO supplementation may be beneficial in animal model of hypertension-related heart failure. Finally, increased plasma TMAO is present in humans consuming seafood-rich diet which is thought to be health-beneficial. We hypothesize that increased plasma TMAO serves as a compensatory response mechanism which protects cells from hydrostatic and osmotic stresses.


Assuntos
Doenças Cardiovasculares/sangue , Metilaminas/sangue , Pressão Osmótica , Animais , Sistema Cardiovascular , Carnitina/metabolismo , Colina/metabolismo , Dieta , Humanos , Pressão Hidrostática , Rim/metabolismo , Fígado/metabolismo , Camundongos , Modelos Teóricos , Ratos , Fatores de Risco
20.
Med Hypotheses ; 129: 109262, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31371080

RESUMO

Dizziness is one of the most common hemodialysis-associated symptoms, and has been thought to be caused by cerebral edema or intravascular hypovolemia. However, the possibility of a peripheral vestibular disturbance due to hemodialysis has not been addressed as a cause of hemodialysis-associated dizziness. In the present study, we propose a new hypothesis accounting for hemodialysis-associated dizziness, i.e., the decrease in serum osmolality due to rapid removal of urea during dialysis causes inner ear fluid dyshomeostasis, leading to density difference between perilymph and endolymph.


Assuntos
Orelha Interna/fisiopatologia , Náusea/complicações , Diálise Renal/efeitos adversos , Transtornos das Sensações/etiologia , Transtornos das Sensações/fisiopatologia , Idoso , Tontura/complicações , Feminino , Humanos , Pressão Hidrostática , Falência Renal Crônica/complicações , Falência Renal Crônica/terapia , Modelos Teóricos , Náusea/fisiopatologia , Concentração Osmolar , Osmose , Pressão Osmótica , Perilinfa , Decúbito Dorsal , Síndrome , Ureia/sangue , Vômito
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