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1.
Prep Biochem Biotechnol ; 49(8): 830-836, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31274051

RESUMO

The current study evaluated the production and characterization of ß-glucosidase by the thermophilic fungus Thermomucor indicae-seudaticae in solid-state fermentation of wheat bran. Isolated fungi have significant amounts of ß-glucosidase, an enzyme that may be applied to different industrial processes, such as the production of fuels, food, and other chemical compounds. Maximal enzyme activity occurred in pH 3.5-4.5 and at 70 °C. The enzyme exhibited high thermostability, for 1 h, up to 60 °C, and good tolerance to glucose (10 mM) and ethanol (10%). The optimization of fermentative parameters on the production of ß-glucosidase was carried out by evaluating the best supplementary nutrient source, pH of nutrient solution, initial substrate moisture and fermentation temperature. The optimization of the above fermentation parameters increased enzyme activity by 120.0%. The highest enzymatic activity (164.0 U/g) occurred with wheat bran containing 70% initial moisture, supplemented with 1.0% (NH4)2SO4 solution at pH 5.5-6.0 and fungus incubated at 40 °C. A more detailed study of ß-glucosidase suggested that Sulfur is an important component of the main amino acid present in this enzyme. The enhancer of the enzyme activity occurred when the fungus was grown on wheat bran supplemented with a sulfur-containing solution. In fact, increasing the concentration of sulfur in the solution increased its activity.


Assuntos
Fibras na Dieta/metabolismo , Microbiologia Industrial/métodos , Mucorales/metabolismo , beta-Glucosidase/metabolismo , Estabilidade Enzimática , Etanol/metabolismo , Fermentação , Glucose/metabolismo , Íons/metabolismo
2.
Plant Physiol Biochem ; 141: 315-324, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31207492

RESUMO

Different SA concentrations (10, 100 and 1000 µM) were applied in young olive trees (Olea europaea L.) subjected to drought and rewatering. Plants treated with 10 µM exhibited a close behavior to SA-starved plants. Although both 100 and 1000 µM improved the balance between ROS production and scavenging, 100 µM was more efficient. During drought, 100 µM improved ROS detoxification and scavenging by the maintenance or overaccumulation of soluble proteins. During recovery, soluble proteins return to well-watered values and increased the investment in non-enzymatic antioxidants. 100 µM was also the most effective in plant ionome regulation, improving macro and micronutrients uptake, namely P, Fe, Mn and Zn, and changing mineral allocation patterns. Therefore, 100 µM also countered the drought-induced decline in total plant biomass accumulation. The application of suitable SA concentrations is an efficient tool to improve cellular homeostasis and growth of plants subjected to recurrent drought episodes.


Assuntos
Secas , Íons/metabolismo , Olea/metabolismo , Oxirredução , Folhas de Planta/metabolismo , Ácido Salicílico/farmacologia , Antioxidantes/química , Biomassa , Minerais/química , Nutrientes/química , Estresse Oxidativo , Fotossíntese/efeitos dos fármacos , Raízes de Plantas/metabolismo , Portugal , Espécies Reativas de Oxigênio/metabolismo , Água/metabolismo
3.
Plant Physiol Biochem ; 139: 651-659, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31048122

RESUMO

Phragmites communis has a long history in Songnen grassland of China and has a series of biological, ecological as well as genetic characteristics contributing to its adaptation to the specific local climatic and edaphic conditions. The aim of the present study was to investigate the ions balance and their relationship to metabolites in P. communis under three salinity stress conditions. Results showed that the contents of Na+, Cl-, and SO42- significantly increased in P. communis leaves, while K+, Mg2+, and Mn2+ decreased. Moreover, Na+ and Cl- had significant negative correlations with metabolites involved in the tricarboxylic acid cycle (TCA cycle), and significant positive correlations with glycolysis. The metabolite results showed that high contents of sugars and proline played important roles in developing salinity tolerance, indicating that glycolysis and proline biosynthesis were enhanced; however, this consumes large amounts of energy and likely caused the TCA cycle to be inhibited. The results suggested that P. communis might enhance its salinity tolerance mainly through increased glycolysis and energy consumption. In addition, restricting Na+ accumulation and increasing of Cl-, and rearrangement of metabolite production in P. communis tissues are possible causes of salinity tolerance. Therefore, salinity caused systems alterations in widespread metabolic networks involving TCA cycle, glycolysis and proline biosynthesis. These findings provided new insights for the P. communis metabolic adaptation to salinity and demonstrated the ions balance and metabolites in P. communis are possibly attributable to development of salinity tolerance.


Assuntos
Íons/metabolismo , Poaceae/metabolismo , Glicólise , Metabolômica , Salinidade
4.
Prep Biochem Biotechnol ; 49(7): 718-726, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31050583

RESUMO

A propanol-tolerant neutral protease was purified and characterized from Bacillus sp. ZG20 in this study. This protease was purified to homogeneity with a specific activity of 26,655 U/mg. The recovery rate and purification fold of the protease were 13.7% and 31.5, respectively. The SDS-PAGE results showed that the molecular weight of the protease was about 29 kDa. The optimal temperature and pH of the protease were 45 °C and 7.0, respectively. The protease exhibited a good thermal- and pH stability, and was tolerant to 50% propanol. Mg2+, Zn2+, K+, Na+ and Tween-80 could improve its activity. The calculated Km and Vmax values of the protease towards α-casein were 12.74 mg/mL and 28.57 µg/(min mL), respectively. This study lays a good foundation for the future use of the neutral protease from Bacillus sp. ZG20.


Assuntos
1-Propanol/metabolismo , Bacillus/enzimologia , Peptídeo Hidrolases/metabolismo , Bacillus/química , Bacillus/metabolismo , Detergentes/metabolismo , Eletroforese em Gel de Poliacrilamida , Estabilidade Enzimática , Peróxido de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Íons/metabolismo , Metais/metabolismo , Peptídeo Hidrolases/química , Peptídeo Hidrolases/isolamento & purificação , Solventes/metabolismo , Especificidade por Substrato , Tensoativos/metabolismo , Temperatura Ambiente
5.
Ecotoxicol Environ Saf ; 179: 127-134, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31030055

RESUMO

The increasing production of Ag nanoparticle (AgNP) containing products has inevitably led to a growing concern about their release into the aquatic environment, along with their potential behaviour, toxicity, and bioaccumulation in marine organisms exposed to NPs released from these products. Hence, this study is focused on the effects of AgNPs in Saccostrea glomerata (rock oyster) in artificial seawater (ASW); evaluating the NP's stability, dissolution, and bioaccumulation rate. AgNPs NM300K (20 ±â€¯5 nm) in concentrations of 12.5 µgL-1 and 125 µgL-1 were used to conduct the experiments, and were compared to a blank and a positive control of 12.5 µgL-1 AgNO3. Dissolution in ASW was measured by ICP-OES and stability was assessed by TEM after 1 h and 3, 5, and 7 days of exposure. Bioaccumulation in gills and digestive glands was measured after 7 days of exposure. The higher concentration of AgNPs induced more aggregation, underwent less dissolution, and showed less bioaccumulation, while the lower concentration showed less aggregation, more dissolution and higher bioaccumulation. Five biomarkers (EROD: ethoxyresorufin-o-deethylase, DNA strand breaks, LPO: lipid peroxidation, GST: glutathione S-transferase and GR: glutathione reductase) were analysed at 0, 3, 5 and 7 days. Significant differences compared to the initial day of exposure (day 0) were reported in DNA strand breaks after 5 and 7 days of exposure, GST, from the third day of exposure, in all the Ag samples, and in some samples for LPO and GR biomarkers, while no significant induction of EROD was observed. A combined effect for each type of treatment and time of exposure was also reported for DNA strand breaks and GST biomarkers measured at the digestive glands. In general, the significant inductions measured showed the following trend: 125 µgL-1 AgNPs >12.5 µgL-1 AgNPs ∼12.5 µgL-1 AgNO3 even though bioaccumulation followed the opposite trend.


Assuntos
Nanopartículas Metálicas/toxicidade , Ostreidae/efeitos dos fármacos , Ostreidae/metabolismo , Prata/metabolismo , Prata/toxicidade , Animais , Biomarcadores/metabolismo , Sistema Digestório/efeitos dos fármacos , Sistema Digestório/metabolismo , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Glutationa Redutase/metabolismo , Glutationa Transferase/metabolismo , Íons/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Água do Mar/química
6.
Biomed Res Int ; 2019: 3702783, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30834261

RESUMO

Increased metabolism accelerates local acid production in cancer tissue. The mechanisms eliminating acidic waste products from human colon cancer tissue represent promising therapeutic targets for pharmacological manipulation in order to improve prognosis for the increasing number of patients with colon cancer. We sampled biopsies of human colonic adenocarcinomas and matched normal colon tissue from patients undergoing colon cancer surgery. We measured steady-state intracellular pH and rates of net acid extrusion in freshly isolated human colonic crypts based on fluorescence microscopy. Net acid extrusion was almost entirely (>95%) Na+-dependent. The capacity for net acid extrusion was increased and steady-state intracellular pH elevated around 0.5 in crypts from colon cancer tissue compared with normal colon tissue irrespective of whether they were investigated in the presence or absence of CO2/HCO3 -. The accelerated net acid extrusion from the human colon cancer tissue was sensitive to the Na+/H+-exchange inhibitor cariporide. We conclude that enhanced net acid extrusion via Na+/H+-exchange elevates intracellular pH in human colon cancer tissue.


Assuntos
Ácidos/metabolismo , Neoplasias do Colo/genética , Trocadores de Sódio-Hidrogênio/genética , Ácidos/química , Bicarbonatos/metabolismo , Dióxido de Carbono/metabolismo , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Neoplasias do Colo/ultraestrutura , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/genética , Guanidinas/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Íons/química , Íons/metabolismo , Masculino , Microscopia de Fluorescência , Trocadores de Sódio-Hidrogênio/metabolismo , Sulfonas/farmacologia , Ativação Transcricional/genética
7.
ACS Appl Mater Interfaces ; 11(15): 14200-14207, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30916937

RESUMO

Organic electronic ion pumps (OEIPs) are versatile tools for electrophoretic delivery of substances with high spatiotemporal resolution. To date, OEIPs and similar iontronic components have been fabricated using thin-film techniques and often rely on laborious, multistep photolithographic processes. OEIPs have been demonstrated in a variety of in vitro and in vivo settings for controlling biological systems, but the thin-film form factor and limited repertoire of polyelectrolyte materials and device fabrication techniques unnecessarily constrain the possibilities for miniaturization and extremely localized substance delivery, e.g., the greater range of pharmaceutical compounds, on the scale of a single cell. Here, we demonstrate an entirely new OEIP form factor based on capillary fibers that include hyperbranched polyglycerols (dPGs) as the selective electrophoretic membrane. The dPGs enable electrophoretic channels with a high concentration of fixed charges and well-controlled cross-linking and can be realized using a simple "one-pot" fluidic manufacturing protocol. Selective electrophoretic transport of cations and anions of various sizes is demonstrated, including "large" substances that are difficult to transport with other OEIP technologies. We present a method for tailoring and characterizing the electrophoretic channels' fixed charge concentration in the operational state. Subsequently, we compare the experimental performance of these capillary OEIPs to a computational model and explain unexpected features in the ionic current for the transport and delivery of larger, lower-mobility ionic compounds. From this model, we are able to elucidate several operational and design principles relevant to miniaturized electrophoretic drug delivery technologies in general. Overall, the compactness of the capillary OEIP enables electrophoretic delivery devices with probelike geometries, suitable for a variety of ionic compounds, paving the way for less-invasive implantation into biological systems and for healthcare applications.


Assuntos
Eletrônica , Eletrônica/instrumentação , Eletroforese , Glicerol/química , Íons/química , Íons/metabolismo , Polímeros/química
8.
Methods Mol Biol ; 1959: 173-183, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30852823

RESUMO

Characterization of protein structure modifications is an important field in mass spectrometry (MS)-based proteomics. Here, we describe a process to quickly and reliably identify a mass change in a targeted protein sequence by top-down mass spectrometry (TD MS) using electron transfer dissociation (ETD). The step-by-step procedure describes how to develop a TD MS method for data acquisition as well as the data analysis process. The described TD MS workflow utilizes diagnostic ions to characterize an unknown sample in a few hours.


Assuntos
Íons/metabolismo , Proteômica , Espectrometria de Massas em Tandem , Biomarcadores , Interpretação Estatística de Dados , Hemoglobinas , Humanos , Proteômica/métodos , Controle de Qualidade
9.
Environ Pollut ; 247: 1100-1109, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30823339

RESUMO

The effects of fulvic acid (FA) and ions on mesophilic pathogenic bacteria survival under freeze-thaw (FT) stress in natural water and its resistant mechanisms are rarely understood. Therefore, survival patterns of Escherichia coli in river water added with various concentrations of FA or FA-ion under FT stress were studied in this work. Meanwhile, cell surface hydrophobicity (CSH), unit activities of superoxide dismutase (SOD) and catalase (CAT) were determined and Escherichia coli morphologies were observed to explore the bacterial resistant mechanisms against FT stress. The results demonstrated that FT cycles significantly reduced bacterial quantities as sampling time, i.e. freeze-thaw cycle time increased. And the biggest reducing rate was observed after the first FT cycle in every system. Ttd values, time needed to reach detection limit under FT stress decreased under FT stress as FA was added into water, while the changes of ttd values were quite complicated when FA and various ions existed together. Generally, the ttd values of FA-cation systems exceeded that of FA system except FA-Ca2+ systems, but it was opposite for FA-anion systems. CSH was heightened after FT cycles and reached peak value at last sampling time in every system. Mechanical constraint from extracellular ice crystals and high CSH induced bacterial aggregation, which protect inner cells of aggregation from extracellular ice crystals. And the unit activities of SOD were significantly higher than those of CAT. Unit activities of SOD and CAT in large part of tested systems increased with sampling time under FT stress, which reduced reactive oxygen species produced from repeated FT cycles. Thus, these could improve the resistance of Escherichia coli to freeze-thaw stress and promote their survival. This work explored the survival pattern and strategy of Escherichia coli in natural water under FT stress.


Assuntos
Benzopiranos/metabolismo , Monitoramento Ambiental/métodos , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Congelamento , Íons/metabolismo , Rios/microbiologia , China , Temperatura Baixa
10.
Biomed Pharmacother ; 111: 1277-1289, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30841441

RESUMO

Neurodegenerative disorders are among the most studied issues both in medicine and pharmacy. Despite long and extensive research, there is no effective treatment prescribed for such diseases, including Alzheimer's or Parkinson's. Available data exposes their multi-faceted character that requires a complex and multidirectional approach to treatment. In this case, the most important challenge is to understand the neurodegenerative mechanisms, which should permit the development of more elaborate and effective therapies. In the submitted review, iron and zinc are discussed as important and perfectly possible neurodegenerative factors behind Alzheimer's and Parkinson's diseases. It is commonly known that these elements are present in living organisms and are essential for the proper operation of the body. Still, their influence is positive only when their proper balance is maintained. Otherwise, when any imbalance occurs, this can eventuate in numerous disturbances, among them oxidative stress, accumulation of amyloid ß and the formation of neurofibrillary tangles, let alone the increase in α-synuclein concentration. At the same time, available research data reveals certain discrepancies in approaching metal ions as either impassive, helpful, or negative factors influencing the development of neurodegenerative changes. This review outlines selected neurodegenerative disorders, highlights the role of iron and zinc in the human body and discusses cases of their imbalance leading to neurodegenerative changes as shown in vitro and in vivo studies as well as through relevant mechanisms.


Assuntos
Doença de Alzheimer/metabolismo , Ferro/metabolismo , Doença de Parkinson/metabolismo , Zinco/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Humanos , Íons/metabolismo , Estresse Oxidativo/fisiologia , alfa-Sinucleína/metabolismo
11.
Eur J Appl Physiol ; 119(3): 685-695, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30730000

RESUMO

PURPOSE: Changes in mean skin temperature (Tsk) have been shown to modify the maximum rate of sweat ion reabsorption. This study aims to extend this knowledge by investigating if modifications could also be caused by local Tsk. METHODS: The influence of local Tsk on the sweat gland maximum ion reabsorption rates was investigated in ten healthy volunteers (three female and seven male; 20.8 ± 1.2 years, 60.4 ± 7.7 kg, 169.4 ± 10.4 cm) during passive heating (water-perfused suit and lower leg water immersion). In two separate trials, in a randomized order, one forearm was always manipulated to 33 °C (Neutral), whilst the other was manipulated to either 30 °C (Cool) or 36 °C (Warm) using water-perfused patches. Oesophageal temperature (Tes), forearm Tsk, sweat rate (SR), galvanic skin conductance (GSC) and salivary aldosterone concentrations were measured. The sweat gland maximum ion reabsorption rates were identified using the ∆SR threshold for an increasing ∆GSC. RESULTS: Thermal [Tes and body temperature (Tb)] and non-thermal responses (aldosterone) were similar across all conditions (p > 0.05). A temperature-dependent response for the sweat gland maximum ion reabsorption rates was evident between 30 °C (0.18 ± 0.10 mg/cm2/min) and 36 °C (0.28 ± 0.14 mg/cm2/min, d = 0.88, p < 0.05), but not for 33 °C (0.22 ± 0.12 mg/cm2/min), d = 0.44 and d = 0.36, p > 0.05. CONCLUSION: The data indicate that small variations in local Tsk may not affect the sweat gland maximum ion reabsorption rates but when the local Tsk increases by > 6 °C, ion reabsorption rates also increase.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Íons/metabolismo , Fenômenos Fisiológicos da Pele , Temperatura Cutânea/fisiologia , Glândulas Sudoríparas/fisiologia , Adulto , Temperatura Baixa/efeitos adversos , Feminino , Antebraço/fisiologia , Calefação , Humanos , Masculino , Pele/inervação , Sudorese/fisiologia , Adulto Jovem
12.
J Fish Biol ; 94(4): 595-605, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30811601

RESUMO

To assess how the quality and properties of the natural dissolved organic carbon (DOC) could drive different effects on gill physiology, we analysed the ionoregulatory responses of a native Amazonian fish species, the tambaqui Colossoma macropomum, to the presence of dissolved organic carbon (DOC; 10 mg l-1 ) at both pH 7.0 and pH 4.0 in ion-poor water. The DOC was isolated from black water from São Gabriel da Cachoeira (SGC) in the upper Rio Negro of the Amazon (Brazil) that earlier been shown to protect a non-native species, zebrafish Danio rerio against low pH under similar conditions. Transepithelial potential (TEP), net flux rates of Na+ , Cl- and ammonia and their concentrations in plasma and Na+ , K+ ATPase; v-type H+ ATPase and carbonic anhydrase activities in gills were measured. The presence of DOC had negligible effects at pH 7.0 apart from lowering the TEP, but it prevented the depolarization of TEP that occurred at pH 4.0 in the absence of DOC. However, contrary to our initial hypothesis, SGC DOC was not protective against the effects of low pH. Colossoma macropomum exposed to SGC DOC at pH 4.0 experienced greater net Na+ and Cl- losses, decreases of Na+ and Cl- concentrations in plasma and elevated plasma ammonia levels and excretion rates, relative to those exposed in the absence of DOC. Species-specific differences and changes in DOC properties during storage are discussed as possible factors influencing the effectiveness of SGC DOC in ameliorating the effects of the acid exposure.


Assuntos
Carbono/análise , Caraciformes/metabolismo , Íons/metabolismo , Água/química , Amônia/análise , Animais , Brasil , Brânquias/fisiologia , Homeostase , Sódio/análise , Água/análise
13.
PLoS Pathog ; 15(2): e1007591, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30716121

RESUMO

Successful host colonization by bacteria requires sensing and response to the local ionic milieu, and coordination of responses with the maintenance of ionic homeostasis in the face of changing conditions. We previously discovered that Mycobacterium tuberculosis (Mtb) responds synergistically to chloride (Cl-) and pH, as cues to the immune status of its host. This raised the intriguing concept of abundant ions as important environmental signals, and we have now uncovered potassium (K+) as an ion that can significantly impact colonization by Mtb. The bacterium has a unique transcriptional response to changes in environmental K+ levels, with both distinct and shared regulatory mechanisms controlling Mtb response to the ionic signals of K+, Cl-, and pH. We demonstrate that intraphagosomal K+ levels increase during macrophage phagosome maturation, and find using a novel fluorescent K+-responsive reporter Mtb strain that K+ is not limiting during macrophage infection. Disruption of Mtb K+ homeostasis by deletion of the Trk K+ uptake system results in dampening of the bacterial response to pH and Cl-, and attenuation in host colonization, both in primary murine bone marrow-derived macrophages and in vivo in a murine model of Mtb infection. Our study reveals how bacterial ionic homeostasis can impact environmental ionic responses, and highlights the important role that abundant ions can play during host colonization by Mtb.


Assuntos
Mycobacterium tuberculosis/metabolismo , Potássio/metabolismo , Adaptação Biológica/fisiologia , Animais , Proteínas de Bactérias/metabolismo , Homeostase , Interações entre Hospedeiro e Microrganismos/fisiologia , Interações Hospedeiro-Patógeno , Íons/metabolismo , Macrófagos , Camundongos , Camundongos Endogâmicos C57BL , Mycobacterium tuberculosis/patogenicidade , Fagossomos , Potássio/fisiologia
14.
Int J Mol Sci ; 20(3)2019 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-30736441

RESUMO

As the main cation in plant cells, potassium plays an essential role in adaptive responses, especially through its involvement in osmotic pressure and membrane potential adjustments. K+ homeostasis must, therefore, be finely controlled. As a result of different abiotic stresses, especially those resulting from global warming, K⁺ fluxes and plant distribution of this ion are disturbed. The hormone abscisic acid (ABA) is a key player in responses to these climate stresses. It triggers signaling cascades that ultimately lead to modulation of the activities of K⁺ channels and transporters. After a brief overview of transcriptional changes induced by abiotic stresses, this review deals with the post-translational molecular mechanisms in different plant organs, in Arabidopsis and species of agronomical interest, triggering changes in K⁺ uptake from the soil, K⁺ transport and accumulation throughout the plant, and stomatal regulation. These modifications involve phosphorylation/dephosphorylation mechanisms, modifications of targeting, and interactions with regulatory partner proteins. Interestingly, many signaling pathways are common to K⁺ and Cl-/NO3- counter-ion transport systems. These cross-talks are also addressed.


Assuntos
Íons/metabolismo , Pressão Osmótica , Fenômenos Fisiológicos Vegetais , Plantas/metabolismo , Estresse Fisiológico , Transporte Biológico , Regulação da Expressão Gênica de Plantas , Transporte de Íons , Plantas/genética , Potássio/metabolismo , Processamento de Proteína Pós-Traducional , Estresse Salino , Transdução de Sinais
15.
Redox Biol ; 21: 101112, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30685709

RESUMO

Intracellular tension activity plays a crucial role in cytotoxic brain edema and astrocyte swelling. Here, a few genetically encoded FRET-based tension probes were designed to detect cytoskeletal structural tension optically, including their magnitude and vectors. The astrocyte swelling resulted in GFAP tension increment, which is associated with the antagonistic effect of inward microfilaments (MFs) and microtubules (MTs) forces. In glutamate-induced astrocyte swelling, GFAP tension rise resulted from outward ion and protein nanoparticle-induced osmotic pressure (PN-OP) increases, where PN-OP could be elicited by MF and MT depolymerization, protein nanoparticle production, and activation of cofilin and stathmin-1. Attenuation of both ion osmotic pressure and PN-OP by drug combinations, together with free-radical scavenger, relieved cerebral edema in vivo. The study suggests that intracellular osmotic pressure (especially PN-OP) has a pivotal role in glutamate-induced astrocyte swelling and brain edema. Recovery of cytoplasmic potential is a promising target to develop new drugs and cure brain edema.


Assuntos
Astrócitos/metabolismo , Edema Encefálico/metabolismo , Ácido Glutâmico/metabolismo , Íons/metabolismo , Pressão Osmótica , Proteínas/metabolismo , Animais , Biomarcadores , Linhagem Celular , Humanos , Imuno-Histoquímica , Espaço Intracelular/metabolismo , Modelos Biológicos , Nanopartículas , Ratos , Estresse Fisiológico
16.
Phys Chem Chem Phys ; 21(6): 3339-3346, 2019 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-30688325

RESUMO

Electroporation is a matter of intensive ongoing research interest, and a much-neglected topic in trans-membrane proteins, particularly in view of such promising potential applications in medicine and biotechnology. In particular, selected such novel and exciting applications are predicated on controlling ionic conductivity through electro-pores. Here, we scrutinise the mechanisms of ions' electric conductivity, by means of structural rearrangements, through quasi-stable electro-pores through human-AQP4 as a well-representative prototype of trans-membrane ionic conduction, achieving exquisite control over ionic permeability manipulated by the application of intense static electric fields.


Assuntos
Aquaporina 4/química , Simulação de Dinâmica Molecular , Aquaporina 4/metabolismo , Condutividade Elétrica , Humanos , Íons/metabolismo , Bicamadas Lipídicas/química , Bicamadas Lipídicas/metabolismo , Permeabilidade
17.
Appl Microbiol Biotechnol ; 103(4): 1851-1864, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30661110

RESUMO

Mitochondrial dysfunction in Saccharomyces cerevisiae was selected as a marker of ion penetration following carbon ion beam (CIB) irradiation. Respiration-deficient mutants were screened. Following confirmation of negligible spontaneous mutation, eight genetically stable S. cerevisiae respiration-deficient mutant strains and a control strain were resequenced with ~ 200-fold read depth. Strategies were established to identify and validate the particular mutations induced by CIB irradiation. In the nuclear genome, CIB irradiation mainly caused base substitutions and some small (< 100 bp) insertions/deletions (indels), which were widely distributed across the chromosomes. Although mitochondrial dysfunction was selected as a screening marker, variants in the nuclear genome were detected at a high frequency (10-7) relative to spontaneous mutations (10-9). The transition to transversion ratio for base substitutions was 0.746, which was less than that of spontaneous mutations. In the mitochondrial genome, there were very large deletions including substantial gene areas, resulting in extremely low read coverage. Meanwhile, every mutant possessed a distinctive mutation pattern, for both the nuclear and the mitochondrial genome. Nuclear genomes contained scanty mitochondrial respiration-related genes that were potentially affected by verified mutations, suggesting that variants in the mitochondrial genome may be the main drivers of respiratory deficiencies. Our study confirmed the previous finding that heavy ion beam (HIB) irradiation mainly induces substantial base substitutions and some small indels but also yielded some novel findings, in particular, novel structural variants in the mitochondrial genomes. These data will enhance the understanding of HIB-induced damage and mutations and aid in the HIB-based microbial mutation breeding.


Assuntos
Carbono/metabolismo , Íons/metabolismo , Mitocôndrias/efeitos da radiação , Mutação , Fosforilação Oxidativa/efeitos da radiação , Saccharomyces cerevisiae/efeitos da radiação , Análise Mutacional de DNA , Genoma Fúngico , Mutagênese , Análise de Sequência de DNA
18.
J Appl Microbiol ; 126(4): 1059-1069, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30637906

RESUMO

AIMS: To understand the bactericidal action of enterocin LD3 against Gram-negative bacteria. METHODS AND RESULTS: Minimum inhibitory concentration (MIC) of enterocin LD3 against Micrococcus luteus MTCC 106 and Escherichia coli NCDC 135 was 80 and 112 µg ml-1 , and minimum bactericidal concentration (MBC) was 128 and 180 µg ml-1 , respectively. The efflux of potassium ion (K+ ) was 14 and 13 ppm and electrical conductivity 10·5 and 8·3 mS cm-1 in cell-free supernatant of MIC-treated cells of M. luteus and E. coli respectively. The increased absorbance (OD260/280 ) 0·422/0·260 and 0·110/0·075 in the bacteriocin-treated cells of M. luteus MTCC 106 and E. coli, NCDC 135, respectively, suggested the release of nucleic acids and proteins. The higher infrared absorbance at 1451·82 and ~1094·30 cm-1 further suggested its interaction with cell membrane and nucleic acids of the target bacteria. The interaction of bacteriocin with nucleic acids was also confirmed using gel retardation assay. Transmission electron microscopy of the bacteriocin-treated cells revealed disruption of cell membrane and leakage of cytoplasmic contents. CONCLUSIONS: Enterocin LD3 demonstrates bactericidal activity against Gram-negative bacteria interacting with cell membrane and nucleic acids. SIGNIFICANCE AND IMPACT OF THE STUDY: The study discloses the possible mechanism of action of enterocin LD3 against Gram-negative bacteria which is a rare phenomenon.


Assuntos
Antibacterianos/farmacologia , Streptococcus faecium ATCC 9790/química , Bactérias Gram-Negativas/efeitos dos fármacos , Íons/metabolismo , Transporte Biológico/efeitos dos fármacos , Hidrocarbonetos Aromáticos com Pontes/farmacologia , Membrana Celular/efeitos dos fármacos , Bactérias Gram-Negativas/metabolismo , Testes de Sensibilidade Microbiana , Ácidos Nucleicos/metabolismo
19.
J Mol Model ; 25(2): 37, 2019 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-30637529

RESUMO

Alzheimer's disease is characterized by the aggregation of Amyloid-ß (Aß) peptide into oligomers, fibrils and plaques. Many factors influencing this process as well as the stability of the various Aß aggregates are known to date, and include the concentration and type of metal ions. Most experimental and theoretical studies have concentrated on heavy metal ions, like Fe2+, Zn2+, or Cu2+, while the smaller alkali ions Li+, Na+, and K+ have not gained much attention notwithstanding their role and ubiquity in physiological environments. In this work, we applied atomistic molecular dynamics simulations to investigate the potential role of these alkali ions in stabilizing fibrillar Aß oligomers of different size and topology, i.e., single and double filament systems comprising 3-24 peptide chains per filament. We find a pronounced difference on the molecular level in the interaction behavior with free carboxylate groups of the Aß oligomer: Li+ forms stable bridged interactions, whereas K+ interacts more transiently and lacks bridging. The behavior of Na+ is in between, so that this ion-protein interaction obeys the renowned Hofmeister series. These differences are also reflected in the ability of the alkali ions to stabilize the oligomer secondary structure. The stabilizing effect is most pronounced for the smaller fibrillar oligomers, suggesting that the type of alkali ion critically affects the initial stages of fibril formation. Our findings thus offer a molecular explanation for the observation that the polymorphisms of Aß fibril structures are caused by differences in the surrounding ionic environment. Graphical abstract Influence of alkali ions on the structure and stability of fibrillar amyloid-ß oligomers.


Assuntos
Peptídeos beta-Amiloides/química , Metais Alcalinos/química , Simulação de Dinâmica Molecular , Conformação Proteica , Multimerização Proteica , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Humanos , Íons/química , Íons/metabolismo , Lítio/química , Lítio/metabolismo , Metais Alcalinos/metabolismo , Potássio/química , Potássio/metabolismo , Agregados Proteicos , Agregação Patológica de Proteínas/metabolismo , Estabilidade Proteica , Sódio/química , Sódio/metabolismo
20.
J Trace Elem Med Biol ; 51: 204-211, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30466932

RESUMO

PURPOSE: Manganese (Mn) is found in environmental and occupational settings, and can cause cognitive and motor impairment. Existing Mn exposure studies have not reached consensus on a valid and reproducible biomarker for Mn exposure. METHODS: Previously, global metabolomics data was generated from urine collected in October 2014 using mass spectrometry (MS). Nine ions were found to be different between persons exposed and unexposed to Mn occupationally, though their identity was not able to be determined. Here, we investigated these nine ions in a follow-up set of urine samples taken from the same cohort in January 2015, and in urine samples from a separate Mn-exposed cohort from Wisconsin. We fit an elastic net model fit using the nine ions found in the October 2014 data. RESULTS: The elastic net correctly predicted exposure status in 72% of the follow-up samples collected in January 2015, and the area under the curve of the receiver operating characteristic (ROC) curve was 0.8. In the Wisconsin samples, the elastic net performed no better than chance in predicting exposure, possibly due to differences in Mn exposure levels, or unmeasured occupational or environmental co-exposures. CONCLUSIONS: This work underscores the importance of taking repeat samples for replication studies when investigating the human urine metabolome, as both within- and between-person variances were observed. Validating and identifying promising results remains a challenge in harnessing global metabolomics for biomarker discovery in occupational cohorts.


Assuntos
Exposição Ambiental/análise , Manganês/urina , Exposição Ocupacional/análise , Adulto , Monitoramento Ambiental , Humanos , Íons/metabolismo , Íons/urina , Manganês/metabolismo , Espectrometria de Massas , Metabolômica , Pessoa de Meia-Idade
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