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Harriette Oldenhof - One of the best experts on this subject based on the ideXlab platform.
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osmotic stress and Membrane Phase changes during freezing of stallion sperm mode of action of cryoprotective agents
Biology of Reproduction, 2013Co-Authors: Harriette Oldenhof, Willem F Wolkers, Marina Gojowsky, Shangping Wang, Samantha Henke, Karl Rohn, H SiemeAbstract:The aim of this study was to determine how different Membrane-permeable and -impermeable cryoprotective agents modulate tolerance of stallion sperm to osmotic stress and stabilize Membranes during cryopreservation. Special emphasis was on hydroxyl ethylene starch (HES), which exposes cells to minimal osmotic stress due to its large molecular weight. Percentages of motile sperm post-thaw were found to be similar when glycerol, sucrose, and HES were used at their optimal concentrations. Percentages of plasma Membrane intact sperm after return to isotonic medium were highest for HES. Fourier transform infrared spectroscopy studies were carried out to study subzero Membrane Phase and permeability behavior. Cryoprotectants were shown to decrease the initial rate of Membrane dehydration during freezing, decrease the activation energy for water transport, and increase the total extent of freezing-induced dehydration. Freezing studies with liposomes as a model system showed that only the Membrane-permeable cryoprotective agents glycerol and ethylene glycol protected Membranes against leakage, whereas egg yolk, sucrose, and HES did not. Differential scanning calorimetry studies showed that sucrose and HES raise the glass transition temperature of the freezing extender and the difference in heat capacity associated with the glass transition. This indicates that these compounds enable formation of a stable glassy matrix at higher subzero temperatures. Sperm cryosurvival rates can be increased by combining different cryoprotectants with different protective functions; Membrane permeable cryoprotective agents stabilize Membranes and modulate the rate of cellular dehydration, whereas di- and polysaccharides increase the glass transition temperature and facilitate storage and handling at higher subzero temperatures.
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Membrane permeability parameters for freezing of stallion sperm as determined by fourier transform infrared spectroscopy
Cryobiology, 2010Co-Authors: Harriette Oldenhof, H Sieme, Katharina Friedel, Birgit Glasmacher, Willem F WolkersAbstract:Abstract Cellular Membranes are one of the primary sites of injury during freezing and thawing for cryopreservation of cells. Fourier transform infrared spectroscopy (FTIR) was used to monitor Membrane Phase behavior and ice formation during freezing of stallion sperm. At high subzero ice nucleation temperatures which result in cellular dehydration, Membranes undergo a profound transition to a highly ordered gel Phase. By contrast, low subzero nucleation temperatures, that are likely to result in intracellular ice formation, leave Membrane lipids in a relatively hydrated fluid state. The extent of freezing-induced Membrane dehydration was found to be dependent on the ice nucleation temperature, and showed Arrhenius behavior. The presence of glycerol did not prevent the freezing-induced Membrane Phase transition, but Membrane dehydration occurred more gradual and over a wider temperature range. We describe a method to determine Membrane hydraulic permeability parameters (ELp, Lpg) at subzero temperatures from Membrane Phase behavior data. In order to do this, it was assumed that the measured freezing-induced shift in wavenumber position of the symmetric CH2 stretching band arising from the lipid acyl chains is proportional to cellular dehydration. Membrane permeability parameters were also determined by analyzing the H2O-bending and -libration combination band, which yielded higher values for both ELp and Lpg as compared to lipid band analysis. These differences likely reflect differences between transport of free and Membrane-bound water. FTIR allows for direct assessment of Membrane properties at subzero temperatures in intact cells. The derived biophysical Membrane parameters are dependent on intrinsic cell properties as well as freezing extender composition.
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freezing and desiccation tolerance in the moss physcomitrella patens an in situ fourier transform infrared spectroscopic study
Biochimica et Biophysica Acta, 2006Co-Authors: Harriette Oldenhof, Willem F Wolkers, John L Bowman, Fern Tablin, John H CroweAbstract:Abstract In situ Fourier transform infrared spectroscopy (FTIR) was used in order to obtain more insights in the underlying protective mechanisms upon freezing and drying of ABA-treated tissues of the moss Physcomitrella patens . The effects of different treatments on the Membrane Phase behaviour, glassy state, and overall protein secondary structure were studied. We found that growth on ABA resulted in the accumulation of sucrose: up to 22% of the tissue on a dry weight basis, compared to only 3.7% in non-ABA-treated tissues. Sucrose functions as a protectant during freezing and drying, but accumulation of sucrose alone is not sufficient for survival. ABA-treated tissue survives a freeze–thaw cycle down to −80 °C only after addition of an additional cryoprotectant (DMSO). Survival correlates with preservation of Membrane Phase behaviour. We found that ABA-treated P. patens can survive slow but not rapid drying down to water contents as low as 0.02 g H 2 O per g DW. Rapidly and slowly dried ABA-treated tissues were found to have similar sugar compositions and glass transition temperatures. The average strength of hydrogen bonding in the cytoplasmic glassy matrix, however, was found to be increased upon slow drying. In addition, slowly dried tissues were found to have a higher relative proportion of α-helical structures compared to rapidly dried tissues.
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Effect of sucrose and maltodextrin on the physical properties and survival of air-dried Lactobacillus bulgaricus: An in situ fourier transform infrared spectroscopy study
Biotechnology Progress, 2005Co-Authors: Harriette Oldenhof, Willem F Wolkers, Stéphanie Passot, Fernanda Fonseca, Michèle MarinAbstract:The effect of sucrose, maltodextrin and skim milk on survival of L. bulgaricus after drying was studied. Survival could be improved from 0.01% for cells that were dried in the absence of protectants to 7.8% for cells dried in a mixture of sucrose and maltodextrin. Fourier transform infrared spectroscopy (FTIR) was used to study the effect of the protectants on the overall protein secondary structure and thermophysical properties of the dried cells. Sucrose, maltodextrin and skim milk were found to have minor effects on the Membrane Phase behavior and the overall protein secondary structure of the dried cells. FTIR was also used to show that the air-dried cell/protectant solutions formed a glassy state at ambient temperature. 1-Palmitoyl 2-oleoyl phosphatidyl choline (POPC) was used in order to determine if sucrose and maltodextrin have the ability to interact with phospholipids during drying. In addition, the glass transition temperature and strength of hydrogen bonds in the glassy state were studied using this model system. Studies using poly-L-lysine were done in order to determine if sucrose and maltodextrin are able to stabilize protein structure during drying. As expected, sucrose depressed the Membrane Phase transition temperature (Tm) of POPC in the dried state and prevented conformational changes of poly-L-lysine during drying. Maltodextrin, however, did not depress the Tm of dried POPC and was less effective in preventing conformational changes of poly-L-lysine during drying. We suggest that when cells are dried in the presence of sucrose and maltodextrin, sucrose functions by directly interacting with biomolecules, whereas maltodextrin functions as an osmotically inactive bulking compound causing spacing of the cells and strengthening of the glassy matrix.
John H Crowe - One of the best experts on this subject based on the ideXlab platform.
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freezing and desiccation tolerance in the moss physcomitrella patens an in situ fourier transform infrared spectroscopic study
Biochimica et Biophysica Acta, 2006Co-Authors: Harriette Oldenhof, Willem F Wolkers, John L Bowman, Fern Tablin, John H CroweAbstract:Abstract In situ Fourier transform infrared spectroscopy (FTIR) was used in order to obtain more insights in the underlying protective mechanisms upon freezing and drying of ABA-treated tissues of the moss Physcomitrella patens . The effects of different treatments on the Membrane Phase behaviour, glassy state, and overall protein secondary structure were studied. We found that growth on ABA resulted in the accumulation of sucrose: up to 22% of the tissue on a dry weight basis, compared to only 3.7% in non-ABA-treated tissues. Sucrose functions as a protectant during freezing and drying, but accumulation of sucrose alone is not sufficient for survival. ABA-treated tissue survives a freeze–thaw cycle down to −80 °C only after addition of an additional cryoprotectant (DMSO). Survival correlates with preservation of Membrane Phase behaviour. We found that ABA-treated P. patens can survive slow but not rapid drying down to water contents as low as 0.02 g H 2 O per g DW. Rapidly and slowly dried ABA-treated tissues were found to have similar sugar compositions and glass transition temperatures. The average strength of hydrogen bonding in the cytoplasmic glassy matrix, however, was found to be increased upon slow drying. In addition, slowly dried tissues were found to have a higher relative proportion of α-helical structures compared to rapidly dried tissues.
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trehalose and sucrose protect both Membranes and proteins in intact bacteria during drying
Applied and Environmental Microbiology, 1995Co-Authors: Samuel B Leslie, John H Crowe, E Israeli, B Lighthart, Lois M CroweAbstract:The microorganisms Escherichia coli DH5 alpha and Bacillus thuringiensis HD-1 show an increased tolerance to freeze-drying when dried in the presence of the disaccharides trehalose and sucrose. When the bacteria were dried with 100 mM trehalose, 70% of the E. coli and 57% of the B. thuringiensis organisms survived, compared with 56 and 44%, respectively, when they were dried with sucrose. Only 8% of the E. coli and 14% of the B. thuringiensis organisms survived drying without the sugars. Fourier transform infrared spectroscopy was used to investigate the role of Membrane Phase transitions in the survival of the organisms during drying and rehydration. Both E. coli and B. thuringiensis showed an increase of 30 to 40 degrees C in the temperature of their phospholipid Phase transition when dried without the sugars, while Phase transition temperatures of those dried with the sugars remained near those of the hydrated cells. A Fourier transform infrared spectroscopy microscope made it possible to investigate the effects of drying on the protein structure in the intact cells. The amide II peak shifts from 1,543 cm-1 in the hydrated cells to about 1,533 cm-1 in the cells dried without sugar. There is no shift in the amide II peak when the cells are dried with trehalose or sucrose. We attribute the increased survival to the sugars' ability to lower the Membrane Phase transition temperature and to protect protein structure in the dry state.(ABSTRACT TRUNCATED AT 250 WORDS)
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trehalose lowers Membrane Phase transitions in dry yeast cells
Biochimica et Biophysica Acta, 1994Co-Authors: Samuel B Leslie, Sarah A Teter, Lois M Crowe, John H CroweAbstract:Recent work has clearly demonstrated a direct correlation between the amount of trehalose present in the yeast Saccharomyces cerevisiae and its ability to tolerate dehydration, but has failed to elucidate the specific role played by trehalose. By using Fourier transform infrared spectroscopy we measured the transition temperature of phospholipids in both intact S. cerevisiae and isolated plasma Membranes dried in the presence and absence of trehalose. Our results show that trehalose lowers the temperature of the dry gel to liquid crystal Phase transition in yeast from around 60°C to about 40°C, thus allowing yeast rehydrated above 40°C to avoid the damaging effects of passing through a Phase transition. These results explain both the need for trehalose and the observation that yeast must be rehydrated with warm water if they are to remain viable. Only when trehalose is present is the dry transition within a physiologically tolerable range and only when the cells are rehydrated above 40°C will they avoid passing through a Phase transition.
Willem F Wolkers - One of the best experts on this subject based on the ideXlab platform.
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osmotic stress and Membrane Phase changes during freezing of stallion sperm mode of action of cryoprotective agents
Biology of Reproduction, 2013Co-Authors: Harriette Oldenhof, Willem F Wolkers, Marina Gojowsky, Shangping Wang, Samantha Henke, Karl Rohn, H SiemeAbstract:The aim of this study was to determine how different Membrane-permeable and -impermeable cryoprotective agents modulate tolerance of stallion sperm to osmotic stress and stabilize Membranes during cryopreservation. Special emphasis was on hydroxyl ethylene starch (HES), which exposes cells to minimal osmotic stress due to its large molecular weight. Percentages of motile sperm post-thaw were found to be similar when glycerol, sucrose, and HES were used at their optimal concentrations. Percentages of plasma Membrane intact sperm after return to isotonic medium were highest for HES. Fourier transform infrared spectroscopy studies were carried out to study subzero Membrane Phase and permeability behavior. Cryoprotectants were shown to decrease the initial rate of Membrane dehydration during freezing, decrease the activation energy for water transport, and increase the total extent of freezing-induced dehydration. Freezing studies with liposomes as a model system showed that only the Membrane-permeable cryoprotective agents glycerol and ethylene glycol protected Membranes against leakage, whereas egg yolk, sucrose, and HES did not. Differential scanning calorimetry studies showed that sucrose and HES raise the glass transition temperature of the freezing extender and the difference in heat capacity associated with the glass transition. This indicates that these compounds enable formation of a stable glassy matrix at higher subzero temperatures. Sperm cryosurvival rates can be increased by combining different cryoprotectants with different protective functions; Membrane permeable cryoprotective agents stabilize Membranes and modulate the rate of cellular dehydration, whereas di- and polysaccharides increase the glass transition temperature and facilitate storage and handling at higher subzero temperatures.
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Membrane permeability parameters for freezing of stallion sperm as determined by fourier transform infrared spectroscopy
Cryobiology, 2010Co-Authors: Harriette Oldenhof, H Sieme, Katharina Friedel, Birgit Glasmacher, Willem F WolkersAbstract:Abstract Cellular Membranes are one of the primary sites of injury during freezing and thawing for cryopreservation of cells. Fourier transform infrared spectroscopy (FTIR) was used to monitor Membrane Phase behavior and ice formation during freezing of stallion sperm. At high subzero ice nucleation temperatures which result in cellular dehydration, Membranes undergo a profound transition to a highly ordered gel Phase. By contrast, low subzero nucleation temperatures, that are likely to result in intracellular ice formation, leave Membrane lipids in a relatively hydrated fluid state. The extent of freezing-induced Membrane dehydration was found to be dependent on the ice nucleation temperature, and showed Arrhenius behavior. The presence of glycerol did not prevent the freezing-induced Membrane Phase transition, but Membrane dehydration occurred more gradual and over a wider temperature range. We describe a method to determine Membrane hydraulic permeability parameters (ELp, Lpg) at subzero temperatures from Membrane Phase behavior data. In order to do this, it was assumed that the measured freezing-induced shift in wavenumber position of the symmetric CH2 stretching band arising from the lipid acyl chains is proportional to cellular dehydration. Membrane permeability parameters were also determined by analyzing the H2O-bending and -libration combination band, which yielded higher values for both ELp and Lpg as compared to lipid band analysis. These differences likely reflect differences between transport of free and Membrane-bound water. FTIR allows for direct assessment of Membrane properties at subzero temperatures in intact cells. The derived biophysical Membrane parameters are dependent on intrinsic cell properties as well as freezing extender composition.
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freezing and desiccation tolerance in the moss physcomitrella patens an in situ fourier transform infrared spectroscopic study
Biochimica et Biophysica Acta, 2006Co-Authors: Harriette Oldenhof, Willem F Wolkers, John L Bowman, Fern Tablin, John H CroweAbstract:Abstract In situ Fourier transform infrared spectroscopy (FTIR) was used in order to obtain more insights in the underlying protective mechanisms upon freezing and drying of ABA-treated tissues of the moss Physcomitrella patens . The effects of different treatments on the Membrane Phase behaviour, glassy state, and overall protein secondary structure were studied. We found that growth on ABA resulted in the accumulation of sucrose: up to 22% of the tissue on a dry weight basis, compared to only 3.7% in non-ABA-treated tissues. Sucrose functions as a protectant during freezing and drying, but accumulation of sucrose alone is not sufficient for survival. ABA-treated tissue survives a freeze–thaw cycle down to −80 °C only after addition of an additional cryoprotectant (DMSO). Survival correlates with preservation of Membrane Phase behaviour. We found that ABA-treated P. patens can survive slow but not rapid drying down to water contents as low as 0.02 g H 2 O per g DW. Rapidly and slowly dried ABA-treated tissues were found to have similar sugar compositions and glass transition temperatures. The average strength of hydrogen bonding in the cytoplasmic glassy matrix, however, was found to be increased upon slow drying. In addition, slowly dried tissues were found to have a higher relative proportion of α-helical structures compared to rapidly dried tissues.
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Effect of sucrose and maltodextrin on the physical properties and survival of air-dried Lactobacillus bulgaricus: An in situ fourier transform infrared spectroscopy study
Biotechnology Progress, 2005Co-Authors: Harriette Oldenhof, Willem F Wolkers, Stéphanie Passot, Fernanda Fonseca, Michèle MarinAbstract:The effect of sucrose, maltodextrin and skim milk on survival of L. bulgaricus after drying was studied. Survival could be improved from 0.01% for cells that were dried in the absence of protectants to 7.8% for cells dried in a mixture of sucrose and maltodextrin. Fourier transform infrared spectroscopy (FTIR) was used to study the effect of the protectants on the overall protein secondary structure and thermophysical properties of the dried cells. Sucrose, maltodextrin and skim milk were found to have minor effects on the Membrane Phase behavior and the overall protein secondary structure of the dried cells. FTIR was also used to show that the air-dried cell/protectant solutions formed a glassy state at ambient temperature. 1-Palmitoyl 2-oleoyl phosphatidyl choline (POPC) was used in order to determine if sucrose and maltodextrin have the ability to interact with phospholipids during drying. In addition, the glass transition temperature and strength of hydrogen bonds in the glassy state were studied using this model system. Studies using poly-L-lysine were done in order to determine if sucrose and maltodextrin are able to stabilize protein structure during drying. As expected, sucrose depressed the Membrane Phase transition temperature (Tm) of POPC in the dried state and prevented conformational changes of poly-L-lysine during drying. Maltodextrin, however, did not depress the Tm of dried POPC and was less effective in preventing conformational changes of poly-L-lysine during drying. We suggest that when cells are dried in the presence of sucrose and maltodextrin, sucrose functions by directly interacting with biomolecules, whereas maltodextrin functions as an osmotically inactive bulking compound causing spacing of the cells and strengthening of the glassy matrix.
Agata Michalska - One of the best experts on this subject based on the ideXlab platform.
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fate of poly 3 octylthiophene transducer in solid contact ion selective electrodes
Analytical Chemistry, 2018Co-Authors: Ewa Jaworska, Maciej Mazur, Krzysztof Maksymiuk, Agata MichalskaAbstract:An experimental approach allowing visualization and quantification of the underestimated spontaneous process of partition of conducting polymer transducer material to the ion-selective Membrane Phase is proposed. The approach proposed is based on optical properties of the transducer material applied, using polythiophene as a model system. It is shown that this process occurs not only during the sensor preparation step but also during pretreatment of the sensor before use. As shown, this uncontrolled partition of the transducer to the receptor leads to conducting polymer contents in the Membrane Phase reaching 0.5% w/w; this process is accompanied by a partial spontaneous change of the oxidation state of polythiophene. The conducting polymer present in the Membrane participates to some extent in the overall response of the sensor, which can be observed as a change in the polythiophene optical emission spectra. Fluorescence microscopic images obtained clearly show that the conducting polymer is distributed ...
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fate of poly 3 octylthiophene transducer in solid contact ion selective electrodes
Analytical Chemistry, 2018Co-Authors: Ewa Jaworska, Maciej Mazur, Krzysztof Maksymiuk, Agata MichalskaAbstract:An experimental approach allowing visualization and quantification of the underestimated spontaneous process of partition of conducting polymer transducer material to the ion-selective Membrane Phase is proposed. The approach proposed is based on optical properties of the transducer material applied, using polythiophene as a model system. It is shown that this process occurs not only during the sensor preparation step but also during pretreatment of the sensor before use. As shown, this uncontrolled partition of the transducer to the receptor leads to conducting polymer contents in the Membrane Phase reaching 0.5% w/w; this process is accompanied by a partial spontaneous change of the oxidation state of polythiophene. The conducting polymer present in the Membrane participates to some extent in the overall response of the sensor, which can be observed as a change in the polythiophene optical emission spectra. Fluorescence microscopic images obtained clearly show that the conducting polymer is distributed throughout the Membrane thickness, being present also at the Membrane/solution interface. The experimental results presented were obtained for K+-selective sensors using poly(3-octylthiophene) as a model transducer; however, the proposed approach is also applicable for other systems.
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all solid state calcium solvent polymeric Membrane electrode for low level concentration measurements
Analytical Chemistry, 2003Co-Authors: Agata Michalska, And Anna Konopka, Magdalena MajzurawskaAbstract:An all-solid-state calcium-selective electrode with a plastic Membrane Phase containing a calcium ionophore ETH1001 placed on poly(3-methylthiophene) ion-to-electron transducting layer functionalized to bind calcium cations has been constructed. The obtained potentiometric sensors were characterized with a calibration line of slope close to Nernstian within the activity from 10-5 to 0.1 M. For Ca2+ activity lower than 10-5 M, super-Nernstian behavior was observed. The super-Nernstian response that is observed for electrodes with an internal solution strongly binding primary ions was in this case attributed to incorporation of calcium ions in the modified solid-contact Phase. With this arrangement, the evaluation of selectivity coefficients much closer to those that depend on the properties of the ion-selective Membrane itself was possible.
Francisco Jose Alguacil - One of the best experts on this subject based on the ideXlab platform.
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carrier facilitated transport of cd ii from a high salinity chloride medium across a supported liquid Membrane containing cyanex 923 in solvesso 100
Desalination, 2005Co-Authors: Francisco Jose Alguacil, Hanan TayibiAbstract:The transport of cadmium (II) from a high-salinity chloride medium across a flat-sheet supported liquid Membrane containing Cyanex 923 in Solvesso 100 supported on a PVDF Membrane into a strip solution with water was investigated. Permeability coefficients of metal increased with decreasing the pH of feed from 2.0 to 0.5. It also increases with increasing carrier concentration in the Membrane Phase, whereas the permeation is dependent on the organic Phase diluent but independent of metal concentration in the feed Phase. The performance of the present system against other carriers was also studied.
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the phosphine oxides cyanex 921 and cyanex 923 as carriers for facilitated transport of chromium vi chloride aqueous solutions
Chemosphere, 2004Co-Authors: Francisco Jose Alguacil, Aurora Lopezdelgado, Manuel Alonso, A M SastreAbstract:The behaviour of the phosphine oxides Cyanex 921 and Cyanex 923 in the facilitated transport of chromium (VI) from chloride solutions is described. Transport is studied as a function of several variables such as stirring speeds of the aqueous Phases, Membrane Phase diluent, hydrochloric acid concentration in the source Phase and chromium and carrier concentrations. The separation of chromium (VI) from other metals presented in the source Phase as well as the behaviour of phosphine oxides with respect to other neutral organophosphorous derivatives (tri-n-butylphosphate (TBP) and dibutyl butylphosphonate (DBBP)) are also investigated. Moreover, by using hydrazine sulphate in the receiving Phase, Cr(VI) is immediately reduced to the less toxic Cr(III).
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facilitated transport and separation of manganese and cobalt by a supported liquid Membrane using dp 8r as a mobile carrier
Hydrometallurgy, 2002Co-Authors: Francisco Jose AlguacilAbstract:The transport of manganese and cobalt ions from sulphate solutions through a supported liquid Membrane containing DP-8R (acidic extractant) dissolved in Exxsol D100 as a mobile carrier was investigated at 20 °C. The transport system was studied as a function of several variables: stirring speed of the source and receiving Phases, concentration of the strippant in the receiving Phase, pH of the source Phase, diluent of the Membrane Phase and extractant and metal concentrations in the Membrane and source Phases, respectively. Higher selectivity in the separation of manganese and cobalt was obtained when the source Phase presented higher [Co]/[Mn] concentration ratios.