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1.
Nano Lett ; 24(22): 6617-6624, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38717095

RESUMEN

The mapping of long-wavelength phonons is important to understand and manipulate the thermal transport in multilayered structures, but it remains a long-standing challenge due to the collective behaviors of phonons. In this study, an experimental demonstration of mapping the long-wavelength phonons in an alloyed Al0.1Ga0.9As/Al0.9Ga0.1As superlattice system is reported. Multiple strategies to filter out the short- to mid-wavelength phonons are used. The phonon mean-free-path-dependent thermal transport properties directly demonstrate both the suppression effect of the ErAs nanoislands and the contribution of long-wavelength phonons. The contribution from phonons with mean free path longer than 1 µm is clearly demonstrated. A model based on the Boltzmann transport equation is proposed to calculate and describe the thermal transport properties, which depicts a clear physical picture of the transport mechanisms. This method can be extended to map different wavelength phonons and become a universal strategy to explore their thermal transport in various application scenarios.

2.
Rapid Commun Mass Spectrom ; 35(5): e9023, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33314314

RESUMEN

RATIONALE: (E)-4-Hydroxy-2-nonenal (HNE) is a reactive secondary product of lipid oxidation with biological significance. The analysis of HNE is a challenge due to its volatility and high activity. Developing sample preparation and analytical tools for the determination of free HNE is crucial for better understanding the actual level of free HNE in meat products. METHODS: Liquid nitrogen freezing, subzero-temperature extraction and derivatization were employed for meat sample treatment. Liquid chromatography/tandem mass spectrometry with electrospray ionization in negative ion mode was used for the determination of free HNE after isotope-coded derivatization. RESULTS: High repeatability and good recoveries with a limit of quantification as low as 0.25 pmol/g were found. Nineteen out of 24 samples, including chilled/processed meat products and meat-based instant foods, were found to contain free HNE with a range of 0.014-1.160 nmol/g. CONCLUSIONS: The proposed method showed satisfactory reliability, sensitivity and accuracy. We believe that such a sample preparation strategy will provide a powerful tool for better understanding the actual level of free HNE in meat products.


Asunto(s)
Aldehídos/análisis , Cromatografía Liquida/métodos , Productos de la Carne/análisis , Espectrometría de Masas en Tándem/métodos , Animales , Cromatografía Liquida/normas , Lípidos/química , Oxidación-Reducción , Estándares de Referencia , Porcinos , Espectrometría de Masas en Tándem/normas
3.
Biochim Biophys Acta Biomembr ; 1860(2): 611-616, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29166573

RESUMEN

Heat shock protein 90 (Hsp90) is an essential molecular chaperone with versatile functions in cell homeostatic control under both normal and stress conditions. Hsp90 has been found to be expressed on the cell surface, but the mechanism of Hsp90 association to the membrane remains obscure. In this study, the direct interaction of Hsp90 and phospholipid vesicles was characterized, and the role of Hsp90 on membrane physical state was explored. Using surface plasmon resonance (SPR), we observed a strong interaction between Hsp90 and different compositions of lipid. Hsp90 had a preference to bind with more unsaturated phospholipid species and the affinity was higher with negatively charged lipids than zwitterionic lipids. Increasing the mole fraction of cholesterol in the phospholipid led to a decrease of binding affinity to Hsp90. Circular dichroism (CD) spectroscopy of Hsp90 in PC membranes showed more α-helix structure than in aqueous buffer. The differential scanning calorimeter (DSC) and fluorescence polarization results showed Hsp90 could affect the transition temperature and fluidity of the bilayer. We postulate from these results that the association between Hsp90 and membranes may involve both electrostatic and hydrophobic force, and constitute a possible mechanism that modulates membrane lipid order during thermal fluctuations.


Asunto(s)
Proteínas HSP90 de Choque Térmico/química , Membrana Dobles de Lípidos/química , Lípidos de la Membrana/química , Fosfolípidos/química , Animales , Unión Competitiva , Rastreo Diferencial de Calorimetría , Colesterol/química , Colesterol/metabolismo , Dicroismo Circular , Patos , Polarización de Fluorescencia , Proteínas HSP90 de Choque Térmico/metabolismo , Membrana Dobles de Lípidos/metabolismo , Fluidez de la Membrana , Lípidos de la Membrana/metabolismo , Fosfatidilcolinas/química , Fosfatidilcolinas/metabolismo , Fosfolípidos/metabolismo , Unión Proteica , Estructura Secundaria de Proteína , Resonancia por Plasmón de Superficie , Temperatura de Transición
4.
Sensors (Basel) ; 18(6)2018 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-29875352

RESUMEN

This work reports a study on the development of a sensitive immunosensor for the assay of actin, which is fabricated using sensing material chitosan-Zn nanoparticles (NPs) and anti-actin modified on glassy carbon electrode respectively. The prepared materials were characterized using transmission electron microscope (TEM), fourier transform infrared spectra (FTIR), X-ray diffraction (XRD) spectra, and circular dichroism (CD) techniques. Meanwhile, the electrochemical properties were studied by linear sweep voltammetric (LSV), electrochemical impedance spectra (EIS), and differential pulse voltammetry (DPV). According to the experiments, under the optimum conditions, the linear fitting equation was I (µA) = -17.31 + 78.97c (R² = 0.9948). The linear range was from 0.0001 to 0.1 mg/mL and the detection limit (LOD, S/N = 3) was 21.52 ng/mL. The interference studies were also performed for checking the sensors' selectivity to actin. With better properties of the chitosan-Zn NPs, the modified electrode is considered as a better candidate than Western blot or immunohistochemical method for real-time usability. The detection limit reported is the lowest till date and this method provides a new approach for quality evaluation.


Asunto(s)
Actinas/aislamiento & purificación , Técnicas Biosensibles , Técnicas Electroquímicas , Nanopartículas del Metal/química , Actinas/química , Quitosano/química , Oro/química , Humanos , Límite de Detección , Zinc/química
5.
Asian-Australas J Anim Sci ; 30(1): 94-99, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27189635

RESUMEN

OBJECTIVE: The aim of this study was to investigate the expression of heat shock protein (HSP) 90, 70, and 60 in chicken muscles and their possible relationship with quality traits of meat. METHODS: The breast muscles from one hundred broiler chickens were analyzed for drip loss and other quality parameters, and the levels of heat shock protein (HSP) 90, 70, and 60 were determined by immunoblots. RESULTS: Based on the data, chicken breast muscles were segregated into low (drip loss≤5%), intermediate (5%0.05). CONCLUSION: Results of this study suggests that higher levels of HSP90 and HSP60 may be advantageous for maintenance of cell function and reduction of water loss, and they could act as potential indicator for better water holding capacity of meat.

6.
J Sci Food Agric ; 96(5): 1467-73, 2016 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-25953510

RESUMEN

BACKGROUND: Adenosine 5'-monophosphate (AMP) is often used in meat and poultry soups as a flavor enhancer (flavor modifier), or as food additives for specific nutritional purposes. Our previous research as well as evidence from others showed that actomyosin could be dissociated into myosin and actin by AMP in extracted muscle solution. However, there is no report available on the application of AMP to dissociate actomyosin and to improve meat tenderness. The objectives of this study were to evaluate the effect of AMP on duck meat tenderness and other quality traits and to explore the mechanism of the action of AMP on meat tenderness. RESULTS: Duck breast muscle was treated with 0, 10, 20, 30, 40 mmol L(-1) AMP at 5 °C for 10 h and examined for shear force, microstructure, actomyosin dissociation, myofibril fragmentation index (MFI), pH, water content, cooking loss, CIE* color (L*, a*, b*), inosine monophosphate (IMP) and free amino acid (FAA) contents. Results showed that shear force, cooking loss, L* and b* of the muscles significantly decreased after AMP treatment (P < 0.05); actomyosin dissociation, MFI, pH, water content, fiber diameter, sarcomere length, IMP and ammonia significantly increased (P < 0.05); no significant change in a* or other FAA content was observed (P > 0.05), and muscle shrinkage in transverse and longitudinal directions were restrained after AMP treatment. CONCLUSION: The results suggest that AMP could notably improve meat tenderness, and this effect was probably mainly through increasing muscle pH, promoting actomyosin dissociation and disrupting the Z-line; meanwhile, the conversion of AMP to IMP may contribute to the flavor of meat.


Asunto(s)
Adenosina Monofosfato/farmacología , Patos , Carne/análisis , Actomiosina/efectos de los fármacos , Animales , Fenómenos Químicos , Aditivos Alimentarios , Fibras Musculares Esqueléticas/efectos de los fármacos , Fibras Musculares Esqueléticas/ultraestructura , Músculo Esquelético/química , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/ultraestructura , Miofibrillas/efectos de los fármacos , Valor Nutritivo , Sarcómeros/efectos de los fármacos , Sarcómeros/ultraestructura , Gusto
7.
Analyst ; 140(3): 797-802, 2015 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-25431808

RESUMEN

The development of advanced nanomaterials for the highly efficient electrical detection of biological species has attracted great attention. Here, novel polypyrrole-Pluronic F127 nanoparticles (PPy-F127 NPs) with conducting and biocompatibility properties were synthesized and used to construct a L-lactic acid biosensor that could be applied in biochemical assays. The PPy-F127 NPs were characterized by transmission electron microscopy (TEM), elemental analysis and UV-vis spectroscopy. Lactate oxidase (LOx) structure variation on the PPy-F127 NPs was investigated by circular dichroism (CD). The cyclic voltammetric results indicated that LOx immobilized on the PPy-F127 NPs exhibited direct electron transfer reaction with a formal potential value (E(0)') of 0.154 V vs. SCE. Moreover, the biosensor had good electrocatalytic activity toward L-lactic acid with a wide linear range (0.015-37.5 mM) and a low detection limit of 0.0088 mM. The regression equation was I (µA) = 0.02353c (mM) + 1.4135 (R(2) = 0.9939). The L-lactic acid biosensor had a good anti-interference property towards uric acid (UA), ascorbic acid (AA), glucose and cysteine. The idea and method provide a promising platform for the rapid development of biosensors that can be used in the detection of biological species.


Asunto(s)
Técnicas Biosensibles/métodos , Electrodos , Ácido Láctico/análisis , Músculo Esquelético/metabolismo , Nanopartículas/química , Polímeros/química , Pirroles/química , Animales , Ácido Ascórbico/análisis , Dicroismo Circular , Cisteína/análisis , Electroquímica , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Glucosa/análisis , Límite de Detección , Microscopía Electrónica de Transmisión , Oxigenasas de Función Mixta/química , Oxigenasas de Función Mixta/metabolismo , Porcinos , Ácido Úrico/análisis
8.
Poult Sci ; 93(10): 2663-7, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25104764

RESUMEN

Rosin was once widely used for removal of duck feathers in China and is still being used secretly in some poultry processing enterprises. Abietic acid (AA) and dehydroabietic acid (DHAA) are the major compounds of rosin. In the present study, 90 duck samples were collected for investigation of AA and DHAA residues. Abietic acid and DHAA were simultaneously detected in 13 out 40 raw ducks, 8 out of 26 water-boiled salted ducks, and 7 out of 24 roasted ducks, respectively. In positive samples, averages of AA were significantly higher than those of DHAA in positive samples of the 3 types of ducks (P < 0.05). Averages of AA and DHAA in positive raw ducks were significantly higher than those in positive roasted ducks (P < 0.05). The results indicated that almost one-third of raw ducks were defeathered by means of rosin-containing defeathering agent, and cooking processes could reduce the AA and DHAA residues to some extent, but could not eliminate them completely.


Asunto(s)
Abietanos/análisis , Culinaria , Carne/análisis , Crianza de Animales Domésticos , Animales , China , Patos
9.
Int J Biol Macromol ; 270(Pt 2): 132516, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38768921

RESUMEN

Endogenous phospholipase A2 (PLA2) plays an important role in phospholipids degradation during cured meat products manufacturing. The present study was undertaken to reveal more information about the endogenous PLA2 in muscles and its role in degradation of intramuscular phospholipids. With the catalytic domain of pork calcium-independent PLA2 (iPLA2cd), impacts of physic-chemical factors on the activity were investigated and substrate specificity of the enzyme were tested respectively. The optimum temperature and pH of pork iPLA2cd were 40 °C and 7.5, respectively. The iPLA2cd could be stimulated by adequate contents of NaCl and ATP, and inhibited by CaCl2 and NaNO2. For native phospholipids, the iPLA2cd was of a little higher affinity towards phosphatidylcholine (PC) than phosphatidylethanolamine (PE), phosphoserine (PS) and phosphatidylinositol (PI). The iPLA2cd could preferentially hydrolyze peroxidized PC over the native PC. The results would help better understand the degradation of phospholipids and the role played by endogenous enzymes during meat products manufacturing.


Asunto(s)
Dominio Catalítico , Fosfatidilcolinas , Fosfolipasas A2 , Animales , Hidrólisis , Fosfatidilcolinas/química , Fosfatidilcolinas/metabolismo , Porcinos , Fosfolipasas A2/metabolismo , Fosfolipasas A2/química , Concentración de Iones de Hidrógeno , Especificidad por Sustrato , Temperatura , Peróxido de Hidrógeno/metabolismo , Peróxido de Hidrógeno/química
10.
Food Chem ; 417: 135914, 2023 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-36933423

RESUMEN

Lipidomic profiles changes of the Sanhuang chicken breast meat during cold storage (4 °C) were analyzed using ultra-high performance liquid chromatography coupled with mass spectrometry (UHPLC-MS)-based lipidomic analysis. Total lipids content decreased 16.8% after storage. Triacylglycerol (TAG), phosphatidylcholine (PC) and phosphatidylethanolamine (PE) significantly decreased, while lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE) increased. Particularly, there was a trend that TAGs with fatty acids of 16:0 and 18:1, and phospholipids containing 18:1, 18:2 and 20:4 were more likely to be downregulated. The increase in the ratio of lysophospholipids/phospholipids and the degree of lipid oxidation demonstrated oxidation and enzymatic hydrolysis are potentially responsible for the lipid transformation. Moreover, 12 lipid species (P < 0.05, VIP > 1, FC < 0.8 or >1.25) were identified to be associated with the spoilage of meat. Glycerophospholipid metabolism and linoleic acid metabolism were the key metabolic pathways involved in the lipid transformations of chilled chicken.


Asunto(s)
Pollos , Lipidómica , Animales , Ácidos Grasos , Espectrometría de Masas
11.
Foods ; 11(7)2022 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-35407067

RESUMEN

Lipoxygenase (LOX) is a major endogenous enzyme for the enzymatic oxidation of lipids during meat storage and meat product manufacturing. In the present work, some characteristics, i.e., effects of inhibitors, selectivity of substrates and specificity of oxidation products, were studied using recombinant porcine 12-lipoxygenase catalytic domain (12-LOXcd). Several familiar inhibitors were found inhibit the activity of recombinant porcine 12-LOXcd;nordihydroguaiaretic acid demonstrated the strongest inhibitory effect. The enzyme could oxygenate common polyunsaturated fatty acids, and showed the highest affinity to linoleic acid (LA), followed by arachidonic acid (AA), linolenic acid (LN) and docosahexaenoic acid (DHA). Under the action of porcine 12-LOXcd, LA was oxidized into four hydroxyoctadecadienoic acid (HODE) isomers, i.e., 13-Z,E-HODE, 13-E,E-HODE, 9-Z,E-HODE and 9-E,E-HODE. Variation of pH not only affected the yield of LA oxidation products, but also the distribution of HODE isomers. These results indicated that endogenous LOX activity and LOX-catalyzed lipid oxidation can be regulated during meat storage and meat product manufacturing.

12.
Adv Mater ; 34(3): e2105778, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34676925

RESUMEN

Interfacial thermal transport plays a prominent role in the thermal management of nanoscale objects and is of fundamental importance for basic research and nanodevices. At metal/insulator interfaces, a configuration commonly found in electronic devices, heat transport strongly depends upon the effective energy transfer from thermalized electrons in the metal to the phonons in the insulator. However, the mechanism of interfacial electron-phonon coupling and thermal transport at metal/insulator interfaces is not well understood. Here, the observation of a substantial enhancement of the interfacial thermal resistance and the important role of surface charges at the metal/ferroelectric interface in an Al/BiFeO3 membrane are reported. By applying uniaxial strain, the interfacial thermal resistance can be varied substantially (up to an order of magnitude), which is attributed to the renormalized interfacial electron-phonon coupling caused by the charge redistribution at the interface due to the polarization rotation. These results imply that surface charges at a metal/insulator interface can substantially enhance the interfacial electron-phonon-mediated thermal coupling, providing a new route to optimize the thermal transport performance in next-generation nanodevices, power electronics, and thermal logic devices.

13.
Food Chem ; 343: 128417, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-33406574

RESUMEN

This study aimed to investigate the structural and antimicrobial properties of Maillard reaction products (MRPs) in chicken liver protein (CLP) and its hydrolysate (CLPH) after sonication (SCLPH). The MRPs of CLP (CLPM), CLPH (CLPHM) and SCLPH (SCLPHM) were analyzed by several spectrometric techniques. The molecular weights of the CLPHM and SCLPHM were primarily between 1.35 kDa and 17 kDa. Moreover, the molecular weights in the CLPHM and SCLPHM below 1.35 kDa were increased, which indicated that cross-linking and thermal degradation occurred during the Maillard reaction (MR). The SCLPHM showed an obvious network skeleton, and the surface had many small crystal-shaped particles after ultrasound treatment and MR by scanning electron microscopy. The SCLPHM had more negative charges than the CLPHM, thus effectively inhibiting the growth of S. saprophyticus and E. coli. MR and ultrasound treatment could be a promising technology to expand the application prospects of low-value meat byproducts.


Asunto(s)
Antibacterianos/química , Hígado/metabolismo , Hidrolisados de Proteína/química , Animales , Antibacterianos/farmacología , Pollos , Escherichia coli/efectos de los fármacos , Reacción de Maillard , Peso Molecular , Hidrolisados de Proteína/farmacología , Sonicación , Staphylococcus saprophyticus/efectos de los fármacos , Temperatura de Transición
14.
Poult Sci ; 99(6): 3280-3285, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32475463

RESUMEN

Defeathering with rosin results in rosin residue in duck skin, which may present as potential risk to human health. Dehydroabietic acid (DHAA) is a major component of rosin. An indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed for determination of DHAA in duck skin. A set of parameters was optimized, including coating antigen concentration, dilution of antiserum, dilution of HRP-IgG antibody, incubation time, and temperature for antigen reaction with antiserum. The indirect competitive ELISA yielded an excellent specificity against DHAA with low cross-reactivity toward other resin acids. The limit of detection and the working concentration range of DHAA in duck skin were 16.4 ng/g and from 40 to 8,060 ng/g, respectively. The indirect competitive ELISA was applied to the determination of DHAA in duck skin samples spiked with DHAA at different contents, and recoveries were found between 78.2 and 97.2%. Finally, DHAA contents in 32 duck samples were quantified by the indirect competitive ELISA and high performance liquid chromatography-fluorescence detector (HPLC-FLD) method. No significant difference was found between DHAA concentrations from indirect competitive ELISA and HPLC-FLD method for all samples, which indicated the indirect competitive ELISA established in this article was of the same accuracy as the HPLC-FLD method. The indirect competitive ELISA was simple, rapid, and reliable, which could be used to identify the duck carcasses defeathered with rosin in the market.


Asunto(s)
Abietanos/metabolismo , Cromatografía Líquida de Alta Presión/veterinaria , Patos/metabolismo , Piel/química , Animales , Cromatografía Líquida de Alta Presión/métodos , Ensayo de Inmunoadsorción Enzimática/métodos , Ensayo de Inmunoadsorción Enzimática/veterinaria , Piel/metabolismo
15.
Food Res Int ; 131: 109010, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32247448

RESUMEN

Novel phosphatidylcholines containing PUFAs and phenolic acids were synthesized from egg phosphatidylcholine (PC), PUFAs (docosahexaenoic, arachidonic and linoleic acids) and phenolic acids (caffeic, ferulic and p-coumaric acids) as substrates. The structures of modified PCs were confirmed by spectral analysis and were evaluated for antioxidant activities. The modified PCs containing caffeic and ferulic acids exhibited excellent antioxidant activities compared with butylated hydroxytoluene (BHT) and α-tocopherol. The synthesized compounds were also evaluated for the oxidative stabilities in liposome and organic solvent. The modified PCs showed more oxidative stable compared with standard PUFA-PCs and PUFA-PCs + BHT. Results showed that the oxidative stability decreased with increasing degree of unsaturation in organic solvent whereas in liposomes, increased with increasing degree of unsaturation due to tight packed configuration. In this study, phenolic acids were found to render protections for PUFAs in modified PCs from oxidation. Modified PCs may have great potential for applications in food, cosmetic and pharmaceutical industries.


Asunto(s)
Antioxidantes/química , Ácidos Grasos Omega-3/química , Ácidos Grasos Omega-6/química , Ácidos Grasos Insaturados/química , Hidroxibenzoatos/química , Fosfatidilcolinas/química , Antioxidantes/metabolismo , Hidroxitolueno Butilado/química , Ácidos Cumáricos/química , Ácido Linoleico/química , Liposomas/química , Oxidación-Reducción , Estrés Oxidativo , alfa-Tocoferol/química
16.
Food Chem ; 313: 125956, 2020 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-31923864

RESUMEN

Crude enzymes were extracted from beef, pork and chicken and were employed to hydrolyze 1-palmitoyl-2-linoleoyl-phosphatidylcholine (PLPC) and oxidized PLPC, i.e. hydroperoxide of PLPC (PLPC-OOH) and hydroxide of PLPC (PLPC-OH). HPLC-ELSD and ESI-MS were used to characterize and determinate hydrolytic products. After hydrolysis at 37 °C for 180 min, 26.8 ~ 27.4%, 21.6 ~ 22.8% and 17.8 ~ 19.0% of substrates were hydrolyzed by crude enzymes from beef, pork and chicken, respectively. Phospholipase A2 (PLA2) was the major contributor to hydrolysis, which accounted for 47.8 ~ 49.6%, 45.8 ~ 48.7% and 46.6 ~ 46.8% of hydrolysis of PLPC, PLPC-OOH and PLPC-OH, respectively. Crude enzymes demonstrated almost same specificities towards PLPC, PLPC-OOH and PLPC-OH. Under actions of crude enzymes, hydroperoxyoctadecadienoic acids (HpODE) and hydroxyoctadecadienoic acids (HODE) were yielded as hydrolytic products of PLPC-OOH and PLPC-OH, respectively. These finding would be helpful to better understand the fate of hydroperoxides of phospholipids and formation of HODE during meat products manufacturing.


Asunto(s)
Músculos/enzimología , Fosfatidilcolinas/metabolismo , Fosfolipasas A2/metabolismo , Animales , Bovinos , Pollos , Cromatografía Líquida de Alta Presión , Ácidos Grasos Insaturados/análisis , Ácidos Grasos Insaturados/metabolismo , Hidrólisis , Fosfatidilcolinas/química , Porcinos
17.
Biochim Biophys Acta Biomembr ; 1861(2): 457-465, 2019 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-30517848

RESUMEN

During heat shock conditions, structural changes in cellular membranes may lead to cell death. Hsp90AA1 and other heat shock proteins involved in membranes are responsible for protecting membrane stabilization. However, the membrane binding mechanism of Hsp90AA1 remains largely uncharacterized. In this study, we showed Hsp90AA1 interacts with phospholipid membrane with high affinity. Using the depth-dependent fluorescence-quenching with brominated lipids, we found Hsp90AA1 penetrated 10.7 Šinto the hydrocarbon core of the lipid bilayer. Circular dichroism spectra studies showed Hsp90AA1 lost part of its α-helical structures upon interaction with phospholipid membrane. By assessing binding properties of the three Hsp90AA1 domains, we found Hsp90AA1 interacted into the lipid bilayer mainly toward its C-terminus domain (CTD). Using scanning electron microscopy, we examined the protection on host cell membrane by overexpressing Hsp90AA1. The results indicated Hsp90AA1 or Hsp90AA1-CTD expressing E. coli cells exhibited better membrane integrity compared to the control after thermal treatment. The following liposome leakage assay suggested the protection of Hsp90AA1 might due to its stabilization of the membrane lipid. Collectively, the present study demonstrates Hsp90AA1 embeds into the lipid bilayer through its C-terminal domain and the Hsp90AA1-lipid association potentially has a significant function in keeping membranes stabilization during stress conditions.


Asunto(s)
Proteínas HSP90 de Choque Térmico/metabolismo , Membrana Dobles de Lípidos/metabolismo , Fosfolípidos/metabolismo , Estrés Fisiológico , Animales , Dicroismo Circular , Patos , Escherichia coli/metabolismo , Escherichia coli/ultraestructura , Proteínas HSP90 de Choque Térmico/química , Respuesta al Choque Térmico , Liposomas , Unión Proteica , Dominios Proteicos , Espectrometría de Fluorescencia , Resonancia por Plasmón de Superficie , Rayos Ultravioleta
18.
Food Chem ; 296: 63-68, 2019 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-31202307

RESUMEN

A Chinese-style sausage was processed using pork as the raw material. During the whole process, 13-hydroxyoctadecadienoic acid (13-HODE), 9-hydroxyoctadecadienoic acid (9-HODE), 9,10-dihydroxyoctadecenoic acid (9,10-DHODE) and 9,10,13-trihydroxyoctadecenoic acid (9,10,13-THODE) kept increasing. All of them were found to be correlated negatively and significantly with lipoxygenases (LOX) activity, and positively and significantly with peroxide value (POV) and thiobarbituric acid reactive substances (TBARS). The ratio of 13-HODE to 9-HODE decreased slowly during drying stage and stayed higher than 2 during the whole process, and it was found to be positively and significantly with LOX activity. The ratio of variation of 13-HODE to variation of 9-HODE in every sampling period (the ratio of Δ13-HODE to Δ9-HODE) decreased sharply from 2.75 in the stage of curing for 12 h to 1.37 in the stage drying from 24 d to 30 d. The changes of ratio of 13HODE to 9-HODE and ratio of Δ13-HODE to Δ9-HODE indicated LOX-catalyzed oxidation predominated in curing and early drying stages, and such predominance was taken over by non-enzymatic oxidation during late drying stage; LOX-catalyzed oxidation was the major contributor to lipids oxidation during the whole process of the Chinese-style sausage preparing.


Asunto(s)
Manipulación de Alimentos/métodos , Ácidos Linoleicos/metabolismo , Peroxidación de Lípido , Productos de la Carne/análisis , China , Ácidos Grasos Insaturados/metabolismo , Ácidos Linoleicos/química , Ácidos Linoleicos Conjugados/química , Ácidos Linoleicos Conjugados/metabolismo , Lipooxigenasas/metabolismo
19.
Zhonghua Nan Ke Xue ; 14(5): 406-10, 2008 May.
Artículo en Zh | MEDLINE | ID: mdl-18572857

RESUMEN

OBJECTIVE: To explore the effect of subchronic exposure to acrylamide on the reproduction and testis endocrine function of rats. METHODS: Forty healthy adult male SD rats were randomly divided into 4 groups of equal number, exposed to acrylamide at the dose of 0, 4, 10 and 18 mg/(kg x d) respectively for 9 weeks, and then subjected to the determination of the hindlimb landing foot splay, sperm vitality and morphology, the activities of acid phosphatase (ACP) and alkaline phosphatase (ALP) in the testis homogenate, and the levels of testosterone (T) and estradiol (E2) in the serum and testis homogenate. Based on the primary Leydig cell culture models exposed to acrylamide of 0, 0.1, 0.75, 4 and 8 mmol/L, the activity of Leydig cells was measured by the CCK-8 method. RESULTS: Following acrylamide exposure, the hindlimb landing foot splay increased markedly with dose increase (P < 0.01). The rates of sperm vitality were (6.86 +/- 5.46)%, (65.43 +/- 5.16)%, (60.86 +/- 4.26)% and (46.86 +/- 2.73)% in the exposed groups, significantly lower than in the control (P < 0.01); the rates of abnormal sperm were (39.00 +/- 10.95)%, (35.43 +/- 7.54)%, (45.71 +/- 13.28)% and (56.71 +/- 17.01)%, significantly increased in the 10 and 18 mg/(kg x d) groups (P < 0.05); ACP activities were (82.93 +/- 11.05), (73.52 +/- 8.77), (77.67 +/- 3.04) and (68.56 +/- 3.09) U/g prot, showing a decreasing tendency, while ALP activities were (0.96 +/- 0.15), (1.07 +/- 0.22), (1.12 +/- 0.22) and (0.74 +/- 0.10) U/g prot, displaying a tendency of first increasing and then decreasing. Both ACP and ALP activities were inhibited significantly in the 18 mg/(kg x d) group as compared with the control (P < 0.05). A marked reduction was noted in T levels in the serum, (13.44 +/- 4.76), (7.69 +/- 3.84), (5.23 +/- 1.42) and (1.36 +/- 0.86) ng/ml, as well as in the testis homogenate, (4.95 +/- 1.64), (3.01 +/- 0.76), (2.44 +/- 0.91) and (0.85 +/- 0.49) ng/mg prot, (P < 0.01), but no significant changes were observed in 17beta-E2 levels. After 24 hours exposure to acrylamide, the optical densities were 0.82 +/- 0.06, 0.56 +/- 0.07, 0.44 +/- 0.06, 0.26 +/- 0.03 and 0.45 +/- 0.21, showing an evident inhibition of the activity of Leydig cells at the dose of 0.1, 0.75, 4 and 8 mmol/L (P < 0.01). CONCLUSION: Subchronic exposure to acrylamide could affect the normal development of sperm, cause changes of the activity of some enzymes in the testis and significantly influence hindlimb motor coordination. Acrylamide directly damages Leydig cells and affects the endocrine function of the testis.


Asunto(s)
Acrilamida/toxicidad , Células Intersticiales del Testículo/efectos de los fármacos , Motilidad Espermática/efectos de los fármacos , Testículo/efectos de los fármacos , Fosfatasa Ácida/metabolismo , Fosfatasa Alcalina/metabolismo , Animales , Células Cultivadas , Epidídimo/citología , Epidídimo/efectos de los fármacos , Epidídimo/metabolismo , Células Intersticiales del Testículo/citología , Células Intersticiales del Testículo/metabolismo , Masculino , Actividad Motora/efectos de los fármacos , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Recuento de Espermatozoides , Espermatozoides/citología , Espermatozoides/efectos de los fármacos , Espermatozoides/fisiología , Testículo/citología , Testículo/metabolismo , Testosterona/sangre , Testosterona/metabolismo , Pruebas de Toxicidad Crónica
20.
Food Chem ; 240: 642-647, 2018 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-28946323

RESUMEN

The antioxidative role of Hsp90 purified from duck muscle on phospholipid was investigated in this study. Lipid oxidation was assessed by ferric thiocyanate method, and particle size, zeta potential measurements and transmission electron microscopy were employed to detect physical and chemical changes during oxidation of liposomes. Increase of the peroxidation products, decrease of the particle size and disruption of the spherical unity of the liposomes were detected when liposome was exposed to hydrogen peroxide (H2O2) oxidation, and Hsp90 was shown to protect liposome against oxidation. To further test the protection of Hsp90 on cell membrane, the Hsp90 transformed E. coli cell model was built. The Hsp90-containing E. coli showed higher survival and better membrane integrity as compared to the control upon H2O2 exposure. It is expected that Hsp90 plays an important role in the prevention of phospholipids oxidation in meat and has potential use as a food antioxidant.


Asunto(s)
Fosfolípidos/metabolismo , Escherichia coli , Proteínas HSP90 de Choque Térmico , Peróxido de Hidrógeno , Peroxidación de Lípido , Liposomas , Especies Reactivas de Oxígeno
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