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1.
PeerJ Comput Sci ; 10: e2255, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39314709

RESUMEN

Single-image super-resolution technology based on deep learning is widely used in remote sensing. The non-local feature reflects the correlation information between different regions. Most neural networks extract various non-local information of images in the spatial domain but ignore the similarity characteristics of frequency distribution, which limits the performance of the algorithm. To solve this problem, we propose a frequency distribution aware network based on discrete cosine transformation for remote sensing image super-resolution. This network first proposes a frequency-aware module. This module can effectively extract the similarity characteristics of the frequency distribution between different regions by rearranging the frequency feature matrix of the image. A global frequency feature fusion module is also proposed. It can extract the non-local information of feature maps at different scales in the frequency domain with little computational cost. The experiments were on two commonly-used remote sensing datasets. The experimental results show that the proposed algorithm can effectively complete image reconstruction and performs better than some advanced super-resolution algorithms. The code is available at https://github.com/Liyszepc/FDANet.

2.
Sensors (Basel) ; 24(15)2024 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-39123823

RESUMEN

To non-destructively and rapidly monitor the chlorophyll content of winter wheat leaves under CO2 microleakage stress, and to establish the quantitative relationship between chlorophyll content and sensitive bands in the winter wheat growing season from 2023 to 2024, the leakage rate was set to 1 L/min, 3 L/min, 5 L/min, and 0 L/min through field experiments. The dimensional reduction was realized, fractional differential processing of a wheat canopy spectrum was carried out, a multiple linear regression (MLR) and partial least squares regression (PLSR) estimation model was constructed using a SPA selection band, and the model's accuracy was evaluated. The optimal model for hyperspectral estimation of wheat SPAD under CO2 microleakage stress was screened. The results show that the spectral curves of winter wheat leaves under CO2 microleakage stress showed a "red shift" of the green peak and a "blue shift" of the red edge. Compared with 1 L/min and 3 L/min, wheat leaves were more affected by CO2 at 5 L/min. Evaluation of the accuracy of the MLR and PLSR models shows that the MLR model is better, where the MLR estimation model based on 1.1, 1.8, 0.4, and 1.7 differential SPAD is the best for leakage rates of 1 L/min, 3 L/min, 5 L/min, and 0 L/min, with validation set R2 of 0.832, 0.760, 0.928, and 0.773, which are 11.528, 14.2, 17.048, and 37.3% higher than the raw spectra, respectively. This method can be used to estimate the chlorophyll content of winter wheat leaves under CO2 trace-leakage stress and to dynamically monitor CO2 trace-leakage stress in crops.


Asunto(s)
Dióxido de Carbono , Clorofila , Hojas de la Planta , Triticum , Triticum/metabolismo , Triticum/química , Hojas de la Planta/química , Hojas de la Planta/metabolismo , Dióxido de Carbono/metabolismo , Clorofila/metabolismo , Clorofila/química , Análisis de los Mínimos Cuadrados , Modelos Lineales , Análisis Espectral/métodos , Estaciones del Año , Estrés Fisiológico/fisiología
3.
Sci Rep ; 14(1): 18976, 2024 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-39152183

RESUMEN

The land use change is the primary factor in influencing the regional carbon emissions. Studying the effects of land use change on carbon emissions can provide supports for the development policies of carbon emission. Using land use and energy consumption data, this study measures carbon emissions from land use dynamics in the Beijing-Tianjin-Hebei region from 2000 to 2020. The standard deviation ellipse model is employed to investigate the distribution characteristics of the spatial patterns of carbon emissions, while the Geographically and Temporally Weighted Regression (GTWR) model is used to examine the contributing factors of carbon emissions and their spatial and temporal heterogeneity. Results indicate a consistently increasing trend in carbon emissions from land use in the Beijing-Tianjin-Hebei region from 2000 to 2020. Construction land is characterized with both the primary source and an increasing intensity of carbon emissions. Besides, the spatial distribution of carbon emissions from land use in the Beijing-Tianjin-Hebei region demonstrates an aggregation pattern from in the northeast-southwest direction towards the center, with a greater aggregation trend in the east-west direction compared to that in the south-north direction. During the study period, a positive correlation was documented between carbon emissions and factors including total population, economic development level, land use degree, and landscape patterns. This correlation showed a decreasing trend and reached a stable level at the end of the study period. Moreover, the analysis showed a negative correlation between industrial structure and carbon emissions, which showed an increasing trend and reached a relatively high level at the end of the study period.

4.
Food Chem ; 404(Pt B): 134656, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36323018

RESUMEN

To uncover the mechanism underlying membrane lipid metabolism of low temperature induced internal browning tolerance in pineapple, membrane phospholipid alterations of harvested 'Comte de Paris' winter pineapple fruit stored at either 10 °C or 25 °C was investigated. Fruit stored at 10 °C developed low levels of internal browning as compared to fruit stored at 25 °C and was associated with high contents of phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, and phosphatidylethanolamine, and low levels of phosphatidic acid. Storage at 10 °C down-regulated the expression levels of phospholipase As. Fruit stored at 10 °C also exhibited high ratio of unsaturated fatty acid to saturated fatty acid and index of unsaturated fatty acid level. These findings suggest that maintenance phospholipid abundance, reduction in phosphatidic acid accumulation and membrane lipid peroxidation may have contributed to the enhanced internal browning tolerance in 'Comte de Paris' winter pineapple fruit at low temperature storage.


Asunto(s)
Ananas , Ananas/metabolismo , Frutas/metabolismo , Ácidos Fosfatidicos , Peroxidación de Lípido , Temperatura , Ácidos Grasos Insaturados/metabolismo
5.
Comput Intell Neurosci ; 2022: 5191871, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36017458

RESUMEN

In this day and age, the necessities for route and situating exactness are getting ever more elevated. The global positioning and navigation system (GPS) can give high-accuracy and long haul route and situating data. But it largely depends on the external environment and is susceptible to environmental disturbances. As a result, the number of visible stars is insufficient, and even placement fails. The research on node positioning technology is of great significance to the research of wireless sensor networks, and node positioning technology is one of the important technologies in wireless sensor networks. Therefore, this paper will introduce the relevant algorithms and technologies of positioning in detail. The purpose of this text is to research how to analyze and research based on Internet of things (IoT) satellite navigation and positioning technology. And the wireless sensor network is described. The two simulation results have showed that, with the positioning technology proposed in this paper, the average positioning error of the anchor node can be kept a small constant regardless of the conditions of different packet sending intervals, changing moving rates, or increasing the transmission power and changing distance. The average positioning error provided in this paper has been kept at about 0.80 m, and the positioning accuracy is high, which is naturally newer and better than the Ssu positioning technology.

6.
Sensors (Basel) ; 22(5)2022 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-35271131

RESUMEN

Hyperspectral images (HSIs) are data cubes containing rich spectral information, making them beneficial to many Earth observation missions. However, due to the limitations of the associated imaging systems and their sensors, such as the swath width and revisit period, hyperspectral imagery over a large coverage area cannot be acquired in a short amount of time. Spectral super-resolution (SSR) is a method that involves learning the relationship between a multispectral image (MSI) and an HSI, based on the overlap region, followed by reconstruction of the HSI by making full use of the large swath width of the MSI, thereby improving its coverage. Much research has been conducted recently to address this issue, but most existing methods mainly learn the prior spectral information from training data, lacking constraints on the resulting spectral fidelity. To address this problem, a novel learning spectral transformer network (LSTNet) is proposed in this paper, utilizing a reference-based learning strategy to transfer the spectral structure knowledge of a reference HSI to create a reasonable reconstruction spectrum. More specifically, a spectral transformer module (STM) and a spectral reconstruction module (SRM) are designed, in order to exploit the prior and reference spectral information. Experimental results demonstrate that the proposed method has the ability to produce high-fidelity reconstructed spectra.

7.
Sensors (Basel) ; 21(22)2021 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-34833637

RESUMEN

Economic globalization is developing more rapidly than ever before. At the same time, economic growth is accompanied by energy consumption and carbon emissions, so it is particularly important to estimate, analyze and evaluate the economy accurately. We compared different nighttime light (NTL) index models with various constraint conditions and analyzed their relationships with economic parameters by linear correlation. In this study, three indices were selected, including original NTL, improved impervious surface index (IISI) and vegetation highlights nighttime-light index (VHNI). In the meantime, all indices were built in a linear regression relationship with gross domestic product (GDP), employed population and power consumption in southeast China. In addition, the correlation coefficient R2 was used to represent fitting degree. Overall, comparing the regression relationships with GDP of the three indices, VHNI performed best with the value of R2 at 0.8632. For the employed population and power consumption regression with these three indices, the maximum R2 of VHNI are 0.8647 and 0.7824 respectively, which are also the best performances in the three indices. For each individual province, the VHNI perform better than NTL and IISI in GDP regression, too. When taking employment population as the regression object, VHNI performs best in Zhejiang and Anhui provinces, but not all provinces. Finally, for power consumption regression, the value of VHNI R2 is better than NTL and IISI in every province except Hainan. The results show that, among the indices under different constraint conditions, the linear relationships between VHNI and GDP and power consumption are the strongest under vegetation constraint in southeast China. Therefore, VHNI index can be used for fitting analysis and prediction of economy and power consumption in the future.


Asunto(s)
Dióxido de Carbono , Carbono , Dióxido de Carbono/análisis , China , Fenómenos Físicos , Análisis de Regresión
8.
J Agric Food Chem ; 69(30): 8578-8589, 2021 Aug 04.
Artículo en Inglés | MEDLINE | ID: mdl-34310150

RESUMEN

Pineapple fruits are usually harvested at different stages of maturity, based on consumer demands. The stage of maturity significantly affects the storage tolerance due to alterations in the cellular lipid homeostasis in the fruits. The characteristic abundance of metabolites and fatty acids (FAs) can provide vital information giving insight into the cellular lipid changes that occur during the ripening process in the fruits. Here, liquid chromatography-tandem mass spectrometry, largely based on the analysis of widely targeted metabolomics, was applied to evaluate the differences in the metabolites among the pineapple at three different stages of maturity namely, pineapples at the young fruit (YF), mature fruit (MF), and fully mature fruit (FMF) stages. In this study, 466 metabolites were annotated and identified. Among these, 59 lipids, including the glyceride esters, fatty acids and conjugates, and lysophospholipids (LPLs) were characterized. Notably, the LPLs were down-regulated in their relative abundance in the MF compared with the YF, and subsequently they remained almost stable in the FMF stage. The FA profiling results revealed the presence of certain unsaturated fatty acids (UFAs); besides, the total monounsaturated fatty acid (MUFA) to saturated fatty acid (SFA) ratio, as well as the polyunsaturated fatty acids (PUFA) to SFA ratio, showed noticeable decrease during the ripening process. The differential accumulation patterns of the LPLs, MUFAs, PUFAs, and SFAs imply that the lipid degradation and peroxidation take place in the pineapple fruits from the YF to MF and YF to FMF stages, respectively. The present study provides new insights into the alterations in the cellular lipid metabolism underlying the metabolite profiles and accumulation of FAs in pineapple fruits during ripening.


Asunto(s)
Ananas , Ácidos Grasos , Frutas , Lípidos , Metaboloma
9.
Sensors (Basel) ; 21(13)2021 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-34206938

RESUMEN

At present, GNSS (Global Navigation Satellite System) positioning technology is widely used for outdoor positioning services because of its high-precision positioning characteristics. However, in indoor environments, effective position information cannot be provided, because of the signals being obscured. In order to improve the accuracy and continuity of indoor positioning systems, in this paper, we propose a PDR/UWB (Pedestrian Dead Reckoning and Ultra Wide Band) integrated navigation algorithm based on an adaptively robust EKF (Extended Kalman Filter) to address the problem of error accumulation in the PDR algorithm and gross errors in the location results of the UWB in non-line-of-sight scenarios. First, the basic principles of UWB and PDR location algorithms are given. Then, we propose a loose combination of the PDR and UWB algorithms by using the adaptively robust EKF. By using the robust factor to adjust the weight of the observation value to resist the influence of the gross error, and by adjusting the variance of the system adaptively according to the positioning scene, the algorithm can improve the robustness and heading factor of the PDR algorithm, which is constrained by indoor maps. Finally, the effectiveness of the algorithm is verified by the measured data. The experimental results showed that the algorithm can not only reduce the accumulation of PDR errors, but can also resist the influence of gross location errors under non-line-of-sight UWB scenarios.

10.
Plant Cell Rep ; 39(1): 35-46, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31501956

RESUMEN

KEY MESSAGE: Banana MaBZR1/2 interact with MaMPK14 to enhance the transcriptional inhibition of cell wall modifying genes including MaEXP2, MaPL2 and MaXET5. Fruit ripening and softening, the major attributes to perishability in fleshy fruits, are modulated by various plant hormones and gene expression. Banana MaBZR1/2, the central transcription factors of brassinosteroid (BR) signaling, mediate fruit ripening through regulation of ethylene biosynthesis, but their possible roles in fruit softening as well as the underlying mechanisms remain to be determined. In this work, we found that MaBZR1/2 directly bound to and repressed the promoters of several cell wall modifying genes such as MaEXP2, MaPL2 and MaXET5, whose transcripts were elevated concomitant with fruit ripening. Moreover, yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays indicated that MaBZR1/2 physically interacted with a mitogen-activated protein kinase MaMPK14, and this interaction strengthened the MaBZR1/2-mediated transcriptional inhibitory abilities. Collectively, our study provides insight into the mechanism of MaBZR1/2 contributing to fruit ripening and softening, which may have potential for banana molecular improvement.


Asunto(s)
Pared Celular/metabolismo , Frutas/crecimiento & desarrollo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Musa/crecimiento & desarrollo , Proteínas de Plantas/metabolismo , Factores de Transcripción/metabolismo , Brasinoesteroides/metabolismo , Proteínas de Unión al ADN/metabolismo , Etilenos/metabolismo , Frutas/genética , Frutas/metabolismo , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Proteínas Quinasas Activadas por Mitógenos/genética , Musa/enzimología , Musa/genética , Musa/metabolismo , Proteínas de Plantas/genética , Regiones Promotoras Genéticas , Factores de Transcripción/genética
11.
PLoS One ; 12(12): e0189991, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29253879

RESUMEN

Avocado is an important tropical fruit with high commercial value, but has a relatively short storage life. In this study, the effects of cold shock treatment (CST) on shelf life of naturally ripened and ethylene-ripened avocado fruits were investigated. Fruits were immersed in ice water for 30 min, then subjected to natural or ethylene-induced ripening. Fruit color; firmness; respiration rate; ethylene production; and the activities of polygalacturonase (PG), pectin methylesterase (PME), and endo-ß-1,4-glucanase were measured. Immersion in ice water for 30 min effectively delayed ripening-associated processes, including peel discoloration, pulp softening, respiration rate, and ethylene production during shelf life. The delay in fruit softening by CST was associated with decreased PG and endo-ß-1,4-glucanase activities, but not PME activity. This method could potentially be a useful postharvest technology to extend shelf life of avocado fruits.


Asunto(s)
Frío , Etilenos/farmacología , Frutas , Persea , Hidrolasas de Éster Carboxílico/química , Pared Celular , Celulasa/química , Pectinas/química , Poligalacturonasa/química , Factores de Tiempo , Agua
12.
Environ Sci Pollut Res Int ; 24(16): 14409-14416, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28432629

RESUMEN

Hydroxylated polyhalodiphenyl ethers (HO-PXDEs) have attracted considerable scientific interest as examples of emerging aquatic pollutants. However, a comprehensive assessment of disposal methods for this particular pollutant was seldom investigated. This study examined the UV light degradation of HO-PXDEs, using 2'-HO-2, 3', 4, 5'-tetrabromodiphenyl ether (2'-HO-BDE-68) as a case study. The results showed that UV light was superior to visible light and electron beam irradiation for producing a high degradation rate of 2'-HO-BDE-68. At low concentrations of HO-BDE, the degradation rate was not obviously improved with decreasing initial concentration. The degradation efficiency was also found to be better in alkaline solutions. In a UV/H2O2 system, the hydroxyl radical provided by H2O2 was shown to enhance the degradation efficiency. The main photolysis products of 2'-HO-BDE-68 were identified, and the possible photodegradation pathways were proposed. 1, 3, 8-Tribromodibenzo-p-dioxin was one of the photoproducts, which indicates that secondary pollution must also be considered with the UV photolysis process.


Asunto(s)
Éteres Difenilos Halogenados/química , Fotólisis , Rayos Ultravioleta , Contaminantes Químicos del Agua/química , Dioxinas , Peróxido de Hidrógeno
13.
Sci Rep ; 6: 32266, 2016 08 26.
Artículo en Inglés | MEDLINE | ID: mdl-27562341

RESUMEN

2, 4-Diacetylphloroglucinol (2,4-DAPG), a natural phenolic compound, has been investigated in light of its biological activities against plant pathogens. To improve its potential application, fourteen 2,4-DAPG analogous were synthesized through the Friedel-Crafts reaction using acyl chlorides and phloroglucinol. Of the 2,4-DAPG derivatives, MP4 exhibited much higher antifungal activity against Penicillium digitatum and P. italicum, the major pathogenic fungi in citrus fruit, than 2, 4-DAPG in vitro, and significantly inhibited the development of decay in harvested mandarin (Citrus reticulata Blanco cv. Shatang.) fruit in vivo. It was found that MP4 resulted in the wrinkle of the hyphae in both fungi with serious folds and breakage. In addition, the expression of several cytochrome P450 (CYP) genes were also modified in both fungi by MP4, which might be associated with the disorder of cell membrane formation. Furthermore, the toxicology of MP4 by evaluating the cell proliferation effect on human normal lung epithelial (16HBE) and kidney 293 (HEK293) cells, was significantly lower than that of albesilate, a widely used fungicide in harvested citrus fruit. In summary, the synthesized MP4 has shown a great potential as a novel fungicide that might be useful for control of postharvest decay in citrus fruit.


Asunto(s)
Antifúngicos/farmacología , Citrus/microbiología , Penicillium/efectos de los fármacos , Penicillium/fisiología , Floroglucinol/análogos & derivados , Antifúngicos/síntesis química , Proliferación Celular/efectos de los fármacos , Sistema Enzimático del Citocromo P-450/genética , Sistema Enzimático del Citocromo P-450/metabolismo , Relación Dosis-Respuesta a Droga , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulación Fúngica de la Expresión Génica/efectos de los fármacos , Células HEK293 , Interacciones Huésped-Patógeno/efectos de los fármacos , Humanos , Hifa/efectos de los fármacos , Hifa/fisiología , Hifa/ultraestructura , Microscopía Electrónica de Rastreo , Estructura Molecular , Penicillium/genética , Floroglucinol/síntesis química , Floroglucinol/farmacología
14.
J Sci Food Agric ; 96(4): 1121-31, 2016 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-25801436

RESUMEN

BACKGROUND: Due to the differences in structure and composition of glycinin and ß-conglycinin, they exhibit different characteristics during heat treatment. In present study, the thermal aggregation behaviour of glycinin, ß-conglycinin and their isolated sub-units was investigated at pH 7.0. RESULTS: Acidic polypeptides, basic polypeptides, αα' and ß sub-units of soy protein were denatured during the isolation process. The degree of aggregation of protein fractions after heat treatment was in the order: denatured basic polypeptides > native glycinin > denatured ß sub-unit > native ß-conglycinin > denatured acidic polypeptides > denatured αα' sub-units. Glycinin, ß-conglycinin, acidic polypeptides and αα'/ß sub-units exhibited different changing trends of surface hydrophobicity with increasing temperature. The αα' sub-units showed higher ability to suppress thermal aggregation of basic polypeptides than ß sub-units during heat treatment. The ß sub-units were shown to form soluble aggregates with glycinin after heating. CONCLUSION: The interaction mechanism of αα' and ß sub-units heated with basic polypeptides was proposed. For the ß sub-units-basic polypeptides mixed system, more hydrophobic chains were binding together and buried inside during heat treatment, which resulted in lower surface hydrophobicity. The αα' sub-units-basic polypeptides mixed system was considered to be a stable system with higher surface hydrophobicity after being heated.


Asunto(s)
Péptidos/química , Proteínas de Soja/química , Electroforesis en Gel de Poliacrilamida , Industria de Alimentos , Globulinas/química , Calor , Humanos , Pliegue de Proteína , Relación Estructura-Actividad
15.
Food Chem Toxicol ; 80: 271-276, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25817020

RESUMEN

Maillard reaction products (MRPs) derived from glucose-cysteine reactions have excellent anti-browning ability. However, there is a lack of information about their acute and sub-chronic toxicities. To our knowledge, the present study is the first to evaluate the acute and sub-chronic toxicities of MRPs in experimental animals. Acute toxicity testing and analysis by Horn's method showed that the median lethal oral dose (LD50) of MRPs in rats was 6.81 g/kg body weight. The sub-chronic toxicity test involved feeding rats with diet containing 0, 0.43, 0.85, or 1.70% (w/w) MRPs for 90 days. These treatments did not affect mortality, gross pathology, histology, hematology, or blood chemistry, and there were no dose-dependent changes in feed consumption. Based on these results, the dietary no-observed-adverse-effect level (NOAEL) for 90-day exposure was 1.29 and 1.51 g MRPs/kg body weight/day for male and female rats, respectively.


Asunto(s)
Cisteína/análogos & derivados , Glucosa/análogos & derivados , Reacción de Maillard , Animales , Cisteína/administración & dosificación , Cisteína/química , Cisteína/toxicidad , Relación Dosis-Respuesta a Droga , Femenino , Análisis de los Alimentos , Glucosa/administración & dosificación , Glucosa/química , Glucosa/toxicidad , Masculino , Ratas , Ratas Sprague-Dawley , Pruebas de Toxicidad
16.
J Agric Food Chem ; 60(12): 3302-10, 2012 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-22372478

RESUMEN

We evaluated the influence of heat treatment on interfacial properties (adsorption at the oil-water interface and dilatational rheology of interfacial layers) of soy protein isolate. The related structural properties of protein affecting these interfacial behaviors, including protein unfolding and aggregation, surface hydrophobicity, and the state of sulfhydryl group, were also investigated. The structural and interfacial properties of soy protein depended strongly on heating temperature (90 and 120 °C). Heat treatment at 90 °C induced an increase in surface hydrophobicity due to partial unfolding of protein, accompanied by the formation of aggregates linked by disulfide bond, and lower surface pressure at long-term adsorption and similar dynamic interfacial rheology were observed as compared to native protein. Contrastingly, heat treatment at 120 °C led to a higher surface activity of the protein and rapid development of intermolecular interactions in the adsorbed layer, as evidenced by a faster increase of surface pressure and dilatational modulus. The interfacial behaviors of this heated protein may be mainly associated with more flexible conformation and high free sulfhydryl group, even if some exposed hydrophobic groups are involved in the formation of aggregates. These results would be useful to better understand the structure dependence of protein interfacial behaviors and to expand utilization of heat-treated protein in the formulation and production of emulsions.


Asunto(s)
Emulsiones/química , Calor , Aceites/química , Proteínas de Soja/química , Agua/química , Adsorción , Elasticidad , Interacciones Hidrofóbicas e Hidrofílicas , Desplegamiento Proteico , Reología , Viscosidad
17.
J Agric Food Chem ; 59(20): 11270-7, 2011 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-21919519

RESUMEN

The amyloid-like fibrillation of soy ß-conglycinin subunits (α, α', and ß) upon heating (0-20 h) at 85 °C and pH 2.0 was characterized using dynamic light scattering, circular dichroism (CD), binding to amyloid dyes (Thioflavin T and Congo red), and atomic force microscopy. The fibrillation of all three subunits was accompanied by progressive polypeptide hydrolysis. The hydrolysis behaviors, fibrillation kinetics, and morphologies of amyloid-like fibrils considerably varied among α, α', and ß subunits. Faster hydrolysis rates and special fragments were observed for the α and α' subunits compared to the ß subunit. However, the order of the fibrillation rate and capacity to form ß-sheets was α' > ß > α, as evidenced by CD and Thioflavin T data. Moreover, sequential growth of twisted screw-structure fibrils, leading to macroscopic fibrils with distinct morphological characteristics, was observed for ß-conglycinin and individual subunits. The different fibrillation kinetics and morphologies of α, α', and ß subunits appear to be associated with the differences in the amino acid composition and typical sequence of peptides. Besides, the disruption of ordered structure of fibrils occurred upon further heating (6-20 h) due to extensive hydrolysis. These results would suggest that all subunits are involved in the fibrillation of ß-conglycinin, following multiple steps including polypeptide hydrolysis, assembly to amyloid structure, and growth into macroscopic fibrils with a fibril shaving process.


Asunto(s)
Amiloide/química , Antígenos de Plantas/química , Globulinas/química , Proteínas de Almacenamiento de Semillas/química , Proteínas de Soja/química , Dicroismo Circular , Calor , Hidrólisis , Luz , Microscopía de Fuerza Atómica , Conformación Proteica , Estructura Secundaria de Proteína , Subunidades de Proteína/química , Dispersión de Radiación
18.
J Agric Food Chem ; 59(13): 7324-32, 2011 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-21609024

RESUMEN

The effects of high hydrostatic pressure (HHP) treatment (100-500 MPa) on solubility and structural properties of ethanol (EtOH)-denatured soy ß-conglycinin and glycinin were investigated using differential scanning calorimetry, Fourier transform infrared and ultraviolet spectroscopy. HHP treatment above 200 MPa, especially at neutral and alkaline pH as well as low ionic strength, significantly improved the solubility of denatured soy proteins. Structural rearrangements of denatured ß-conglycinin subjected to high pressure were confirmed, as evidenced by the increase in enthalpy value (ΔH) and the formation of the ordered supramolecular structure with stronger intramolecular hydrogen bond. HHP treatment (200-400 MPa) caused an increase in surface hydrophobicity (F(max)) of ß-conglycinin, partially attributable to the exposure of the Tyr and Phe residues, whereas higher pressure (500 MPa) induced the decrease in F(max) due to hydrophobic rearrangements. The Trp residues in ß-conglycinin gradually transferred into a hydrophobic environment, which might further support the finding of structural rearrangements. In contrast, increasing pressure induced the progressive unfolding of denatured glycinin, accompanied by the movement of the Tyr and Phe residues to the molecular surface of protein. These results suggested that EtOH-denatured ß-conglycinin and glycinin were involved in different pathways of structural changes during HHP treatment.


Asunto(s)
Etanol/química , Presión Hidrostática , Desnaturalización Proteica , Proteínas de Soja/química , Antígenos de Plantas/química , Globulinas/química , Proteínas de Almacenamiento de Semillas/química , Solubilidad , Termodinámica
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