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André Brodkorb - One of the best experts on this subject based on the ideXlab platform.

  • Formation of cytotoxic α-lactalbumin / Sodium Oleate complexes: Concentration and temperature effects
    International Dairy Journal, 2014
    Co-Authors: Joseph J. Kehoe, Kamila Lišková, Nora M. O'brien, Alan L. Kelly, André Brodkorb
    Abstract:

    Abstract Cytotoxic complexes may be formed by mixing whey proteins and oleic acid or Sodium Oleate. The present study investigated the kinetics of complex formation when the whey protein α-lactalbumin (α-LA) is mixed with Sodium Oleate. Intrinsic fluorescence showed that the complex formed at room temperature during the mixing of α-LA and Sodium Oleate. However, some of the structural changes brought about by the binding of the Sodium Oleate can be reversed by dialysis, when loosely bound Oleate is removed. During dialysis, solutions with lower protein concentrations had reduced buffering capacity, and so the pH decreased more; this decrease in pH was correlated with a loss of Oleate from the complex. The cytotoxicity of all the samples produced in this study was strongly correlated with the amount of Oleate bound in the complex, confirming previous studies that suggested that oleic acid is the cytotoxic agent in the complex.

  • Interactions between Sodium Oleate and α-lactalbumin: The effect of temperature and concentration on complex formation
    Food Hydrocolloids, 2014
    Co-Authors: Joseph J. Kehoe, André Brodkorb
    Abstract:

    Complexes of α-lactalbumin and oleic acid have previously been shown to be cytotoxic to cancer cells. In this study oleic acid is replaced by the more soluble Sodium Oleate and complexes of α-lactalbumin and Sodium Oleate are formed. Dynamic light scattering results showed that there was a small linear increase in the particle size of α-lactalbumin when it was titrated with Sodium Oleate. The fluorescence spectra of α-lactalbumin showed a linear increase in the emission maximum when Sodium Oleate was added up to a molar ratio of 8-11 Oleate molecules per α-lactalbumin. Differential scanning calorimetry results show that the thermal unfolding of α-lactalbumin is altered by the presence of the Sodium Oleate. There is a decrease in size of the endothermic peak of apo α-lactalbumin when Sodium Oleate is added. The temperature at which unfolding occurred decreased for both apo and holo α-lactalbumin. FTIR measurements showed no significant effect of Sodium Oleate in the amide I region of the α-lactalbumin spectrum indicating the presence of Oleate has little or no effect on the secondary structure of α-lactalbumin. The interactions between α-lactalbumin and Sodium Oleate/oleic acid are pH dependent, turbidity and dynamic light scattering measurements showed that the association between the two was optimal between pH 6.0 and 8.0.The results obtained here suggest that α-lactalbumin can bind at least a 20fold molar excess of Oleate, most likely in a non-specific manner. © 2012 Elsevier Ltd.

  • interactions between Sodium Oleate and α lactalbumin the effect of temperature and concentration on complex formation
    Food Hydrocolloids, 2014
    Co-Authors: Joseph J. Kehoe, André Brodkorb
    Abstract:

    Abstract Complexes of α-lactalbumin and oleic acid have previously been shown to be cytotoxic to cancer cells. In this study oleic acid is replaced by the more soluble Sodium Oleate and complexes of α-lactalbumin and Sodium Oleate are formed. Dynamic light scattering results showed that there was a small linear increase in the particle size of α-lactalbumin when it was titrated with Sodium Oleate. The fluorescence spectra of α-lactalbumin showed a linear increase in the emission maximum when Sodium Oleate was added up to a molar ratio of 8–11 Oleate molecules per α-lactalbumin. Differential scanning calorimetry results show that the thermal unfolding of α-lactalbumin is altered by the presence of the Sodium Oleate. There is a decrease in size of the endothermic peak of apo α-lactalbumin when Sodium Oleate is added. The temperature at which unfolding occurred decreased for both apo and holo α-lactalbumin. FTIR measurements showed no significant effect of Sodium Oleate in the amide I region of the α-lactalbumin spectrum indicating the presence of Oleate has little or no effect on the secondary structure of α-lactalbumin. The interactions between α-lactalbumin and Sodium Oleate/oleic acid are pH dependent, turbidity and dynamic light scattering measurements showed that the association between the two was optimal between pH 6.0 and 8.0. The results obtained here suggest that α-lactalbumin can bind at least a 20 fold molar excess of Oleate, most likely in a non-specific manner.

Masanori Fujinami - One of the best experts on this subject based on the ideXlab platform.

  • Experimental Investigation of the Self-Propelled Motion of a Sodium Oleate Tablet and Boat at an Oil–Water Interface
    Langmuir, 2018
    Co-Authors: Yasuhito Watahiki, Tomonori Nomoto, Luca Chiari, Taro Toyota, Masanori Fujinami
    Abstract:

    The self-propelled behaviors of macroscopic inanimate objects at surfaces and interfaces are ubiquitous phenomena of fundamental interest in interface science. However, given the existence of a large variety of systems with their own inherent chemical properties, the kinematics of the self-propelled motion and the dynamics of the forces driving these systems often remain largely unknown. Here, we experimentally investigate the spontaneous motion of a Sodium Oleate tablet at a water–nitrobenzene interface, under nonequilibrium and global isothermal conditions, through measurements of the interfacial tension with the noninvasive, quasi-elastic laser scattering method. The Sodium Oleate tablet was self-propelled due to an imbalance in the interfacial tension induced by the inhomogeneous adsorption of Oleate/oleic acid molecules. The kinetics of the self-propelled motion of a boat-shaped plastic sheet bearing Sodium Oleate tablets at a Sodium Oleate aqueous solution–nitrobenzene interface was also studied. Th...

  • experimental investigation of the self propelled motion of a Sodium Oleate tablet and boat at an oil water interface
    Langmuir, 2018
    Co-Authors: Yasuhito Watahiki, Tomonori Nomoto, Luca Chiari, Taro Toyota, Masanori Fujinami
    Abstract:

    The self-propelled behaviors of macroscopic inanimate objects at surfaces and interfaces are ubiquitous phenomena of fundamental interest in interface science. However, given the existence of a large variety of systems with their own inherent chemical properties, the kinematics of the self-propelled motion and the dynamics of the forces driving these systems often remain largely unknown. Here, we experimentally investigate the spontaneous motion of a Sodium Oleate tablet at a water–nitrobenzene interface, under nonequilibrium and global isothermal conditions, through measurements of the interfacial tension with the noninvasive, quasi-elastic laser scattering method. The Sodium Oleate tablet was self-propelled due to an imbalance in the interfacial tension induced by the inhomogeneous adsorption of Oleate/oleic acid molecules. The kinetics of the self-propelled motion of a boat-shaped plastic sheet bearing Sodium Oleate tablets at a Sodium Oleate aqueous solution–nitrobenzene interface was also studied. Th...

Joseph J. Kehoe - One of the best experts on this subject based on the ideXlab platform.

  • Formation of cytotoxic α-lactalbumin / Sodium Oleate complexes: Concentration and temperature effects
    International Dairy Journal, 2014
    Co-Authors: Joseph J. Kehoe, Kamila Lišková, Nora M. O'brien, Alan L. Kelly, André Brodkorb
    Abstract:

    Abstract Cytotoxic complexes may be formed by mixing whey proteins and oleic acid or Sodium Oleate. The present study investigated the kinetics of complex formation when the whey protein α-lactalbumin (α-LA) is mixed with Sodium Oleate. Intrinsic fluorescence showed that the complex formed at room temperature during the mixing of α-LA and Sodium Oleate. However, some of the structural changes brought about by the binding of the Sodium Oleate can be reversed by dialysis, when loosely bound Oleate is removed. During dialysis, solutions with lower protein concentrations had reduced buffering capacity, and so the pH decreased more; this decrease in pH was correlated with a loss of Oleate from the complex. The cytotoxicity of all the samples produced in this study was strongly correlated with the amount of Oleate bound in the complex, confirming previous studies that suggested that oleic acid is the cytotoxic agent in the complex.

  • Interactions between Sodium Oleate and α-lactalbumin: The effect of temperature and concentration on complex formation
    Food Hydrocolloids, 2014
    Co-Authors: Joseph J. Kehoe, André Brodkorb
    Abstract:

    Complexes of α-lactalbumin and oleic acid have previously been shown to be cytotoxic to cancer cells. In this study oleic acid is replaced by the more soluble Sodium Oleate and complexes of α-lactalbumin and Sodium Oleate are formed. Dynamic light scattering results showed that there was a small linear increase in the particle size of α-lactalbumin when it was titrated with Sodium Oleate. The fluorescence spectra of α-lactalbumin showed a linear increase in the emission maximum when Sodium Oleate was added up to a molar ratio of 8-11 Oleate molecules per α-lactalbumin. Differential scanning calorimetry results show that the thermal unfolding of α-lactalbumin is altered by the presence of the Sodium Oleate. There is a decrease in size of the endothermic peak of apo α-lactalbumin when Sodium Oleate is added. The temperature at which unfolding occurred decreased for both apo and holo α-lactalbumin. FTIR measurements showed no significant effect of Sodium Oleate in the amide I region of the α-lactalbumin spectrum indicating the presence of Oleate has little or no effect on the secondary structure of α-lactalbumin. The interactions between α-lactalbumin and Sodium Oleate/oleic acid are pH dependent, turbidity and dynamic light scattering measurements showed that the association between the two was optimal between pH 6.0 and 8.0.The results obtained here suggest that α-lactalbumin can bind at least a 20fold molar excess of Oleate, most likely in a non-specific manner. © 2012 Elsevier Ltd.

  • interactions between Sodium Oleate and α lactalbumin the effect of temperature and concentration on complex formation
    Food Hydrocolloids, 2014
    Co-Authors: Joseph J. Kehoe, André Brodkorb
    Abstract:

    Abstract Complexes of α-lactalbumin and oleic acid have previously been shown to be cytotoxic to cancer cells. In this study oleic acid is replaced by the more soluble Sodium Oleate and complexes of α-lactalbumin and Sodium Oleate are formed. Dynamic light scattering results showed that there was a small linear increase in the particle size of α-lactalbumin when it was titrated with Sodium Oleate. The fluorescence spectra of α-lactalbumin showed a linear increase in the emission maximum when Sodium Oleate was added up to a molar ratio of 8–11 Oleate molecules per α-lactalbumin. Differential scanning calorimetry results show that the thermal unfolding of α-lactalbumin is altered by the presence of the Sodium Oleate. There is a decrease in size of the endothermic peak of apo α-lactalbumin when Sodium Oleate is added. The temperature at which unfolding occurred decreased for both apo and holo α-lactalbumin. FTIR measurements showed no significant effect of Sodium Oleate in the amide I region of the α-lactalbumin spectrum indicating the presence of Oleate has little or no effect on the secondary structure of α-lactalbumin. The interactions between α-lactalbumin and Sodium Oleate/oleic acid are pH dependent, turbidity and dynamic light scattering measurements showed that the association between the two was optimal between pH 6.0 and 8.0. The results obtained here suggest that α-lactalbumin can bind at least a 20 fold molar excess of Oleate, most likely in a non-specific manner.

Yasuhito Watahiki - One of the best experts on this subject based on the ideXlab platform.

  • Experimental Investigation of the Self-Propelled Motion of a Sodium Oleate Tablet and Boat at an Oil–Water Interface
    Langmuir, 2018
    Co-Authors: Yasuhito Watahiki, Tomonori Nomoto, Luca Chiari, Taro Toyota, Masanori Fujinami
    Abstract:

    The self-propelled behaviors of macroscopic inanimate objects at surfaces and interfaces are ubiquitous phenomena of fundamental interest in interface science. However, given the existence of a large variety of systems with their own inherent chemical properties, the kinematics of the self-propelled motion and the dynamics of the forces driving these systems often remain largely unknown. Here, we experimentally investigate the spontaneous motion of a Sodium Oleate tablet at a water–nitrobenzene interface, under nonequilibrium and global isothermal conditions, through measurements of the interfacial tension with the noninvasive, quasi-elastic laser scattering method. The Sodium Oleate tablet was self-propelled due to an imbalance in the interfacial tension induced by the inhomogeneous adsorption of Oleate/oleic acid molecules. The kinetics of the self-propelled motion of a boat-shaped plastic sheet bearing Sodium Oleate tablets at a Sodium Oleate aqueous solution–nitrobenzene interface was also studied. Th...

  • experimental investigation of the self propelled motion of a Sodium Oleate tablet and boat at an oil water interface
    Langmuir, 2018
    Co-Authors: Yasuhito Watahiki, Tomonori Nomoto, Luca Chiari, Taro Toyota, Masanori Fujinami
    Abstract:

    The self-propelled behaviors of macroscopic inanimate objects at surfaces and interfaces are ubiquitous phenomena of fundamental interest in interface science. However, given the existence of a large variety of systems with their own inherent chemical properties, the kinematics of the self-propelled motion and the dynamics of the forces driving these systems often remain largely unknown. Here, we experimentally investigate the spontaneous motion of a Sodium Oleate tablet at a water–nitrobenzene interface, under nonequilibrium and global isothermal conditions, through measurements of the interfacial tension with the noninvasive, quasi-elastic laser scattering method. The Sodium Oleate tablet was self-propelled due to an imbalance in the interfacial tension induced by the inhomogeneous adsorption of Oleate/oleic acid molecules. The kinetics of the self-propelled motion of a boat-shaped plastic sheet bearing Sodium Oleate tablets at a Sodium Oleate aqueous solution–nitrobenzene interface was also studied. Th...

Tommy Nylander - One of the best experts on this subject based on the ideXlab platform.

  • phase behavior in the biologically important oleic acid Sodium Oleate water system
    Chemistry and Physics of Lipids, 2017
    Co-Authors: Stefania Mele, Olle Soderman, Helena Ljusbergwahren, Krister Thuresson, Maura Monduzzi, Tommy Nylander
    Abstract:

    Abstract The phase behavior in the oleic acid/Sodium Oleate/normal saline (0.15 M NaCl aqueous solution) system has been determined. For this purpose visual inspection of samples between crossed polarizers, and Small Angle X-ray diffraction was used to identify the various phases and their unit cell dimensions. A rich phase behavior was observed for the ternary system, featuring reverse micellar, micellar cubic, hexagonal, and cubic phases, and large regions with lamellar phases. As expected the ratio the ‘oleic acid/Sodium Oleate’ determines the pH and as a consequence the phase behavior. The results could be modeled by an extended Henderson–Hasselbalch (HH) equation, which takes into account the electrostatic potential at the aqueous lipid interface. The knowledge obtained is important for understanding the lipolysis of triglycerides, as the phase behavior of the end-product of the reaction regulates how well the insoluble product can be dispersed and consequently the kinetics of the process.