Sorbitol Solution Research Articles

Loading process of sugars into cabbage petiole and asparagus shoot apex cells by incubation with hypertonic sugar solutions

The freezing tolerance of cabbage petioles and asparagus shoot apexes was increased by preincubation with 0.8 M sugar solutions. In cabbage petioles with an initial freezing tolerance of -3 degrees C (temperature for 50% cell survival), as determined by both electrolyte leakage and fluorescein diacetate vital staining, the freezing tolerance was increased to -13 degrees C by incubation with sorbitol solutions for 3 h. In meristematic cells of asparagus shoot apexes with an initial freezing tolerance of -7.5 degrees C, as determined by fluorescein diacetate vital staining, the freezing tolerance was increased to -30 degrees C by incubation with 0.8 M sugar solutions for 3 h, although other cells in the shoot apexes were killed by higher freezing temperatures. During incubation of both cabbage petioles and asparagus shoot apexes with sugar solutions, sugars were intracellularly taken up by osmotically induced fluid-phase endocytotic vesicles, as indicated by comovement of Lucifer Yellows carbohydrazide (LYCH) observed with a confocal laser scanning microscope. The amounts of intracellularly taken up sugars increased concomitantly with the formation of endocytotic vesicles depending on the time of incubation in parallel with a gradual increase of freezing tolerance. However, the endocytotic vesicles and their contents were retained not only after prolonged incubation after maximum freezing tolerance had been achieved but also after recovery of these tissue cells to isotonic conditions or after freeze-thawing. These results suggest that although sugars are intracellularly taken up by endocytotic vesicles, they might be sequestered within vesicles, casting doubt on their protective role to the plasma membranes as a main site of freezing injury. The pretreatment with 1 mM p-chloromercuribenzenesulfonic acid (PCMBS), an inhibitor of sugar transport, reduced the amounts of intracellular sugar uptake without affecting the formation of endocytotic vesicles, suggesting that sugars were, at least partly, taken up by sugar transporters. In the pretreatment with PCMBS, the freezing tolerance of incubated tissues with sugar solutions was significantly reduced, although addition of PCMBS per se did not affect survival. These results suggest that sugars taken up by sugar transporters, rather than sugars taken up by endocytotic vesicles, are mainly responsible for the increased freezing tolerance of cabbage petioles and asparagus shoot apexes. Furthermore, we aimed to study the occurrence of fluid-phase endocytosis with LYCH in an isotonic condition. Our results indicated that uptake of LYCH by fluid-phase endocytotic vesicles was not detected microscopically in isotonic condition, although LYCH was spectrofluorimetrically taken up in isotonic condition. Spectrofluorimetric uptake of LYCH was inhibited by addition of probenecid, an anion transport inhibitor. These results suggest that in cabbage petioles and asparagus shoot apexes, LYCH is taken up by anion transport but not by fluid-phase endocytosis in isotonic condition, and uptake of LYCH by fluid-phase endocytosis is restricted to occur only in hypertonic condition.

Repetitive action potentials induced in Arabidopsis thaliana leaves by wounding and potassium chloride application

A procedure (named prick-and-drop treatment) generating action potentials in the plant model Arabidopsis thaliana is described here, opening new possibilities for the analysis and understanding of the genuine nature of this phenomenon. Bioelectrical measurements were made on the petiole of the C24 ecotype with extracellular electrodes. The stimulating method includes wounding of a small area of the distal part of the leaf and subsequent addition of a drop of different kinds of solutions. The treatment inducing action potentials (APs) consists in a drop of KCl (> 0.25 M) applied on a wound, moreover the frequency of APs increased with the augmentation of the KCl concentration. Two molar sorbitol solutions were ineffective in causing APs, indicating that the effect of KCl solution is not due to the osmotic effect. Neither pricking nor addition of KCl alone caused repetitive APs (RAP), suggesting that the diffusion of the KCl solution into the apoplastic space through the wounding area is essential. The bioelectrical responses induced with 1 M KCl consisted of 35 % of ultra-rapid APs (propagation rates > 4 mm·s –1). The other APs propagated at 1.7 ± 0.9 mm·s –1. Variation potentials (VPs) were also observed, and were characterised by a larger wave (longer event duration) with a slower propagation velocity (0.3 ± 0.1 mm·s –1) than the APs. A dark phase inserted during the light period led to a decrease of the amplitudes and the frequency of appearance of APs, but their velocity stayed unchanged. Our experiments demonstrate the efficiency of our method (> 90 %) to induce spontaneous APs in A. thaliana for more than 2 h.

An evaluation of the acidogenic potential of maltodextrins in vivo

Maltodextrins are a group of oligosaccharides, which are being increasingly used as a source of carbohydrate in many commercially available foods and drinks. This study investigated the effect of three different maltodextrins on the pH of dental plaque, in vivo, in 10 adult volunteers using the plaque harvesting method. The three maltodextrins tested in this study were DE=5.5, 14.0 and 18.5 (DE=dextrose equivalents), made up as 10% solutions. Also, three commercially available maltodextrin containing children's drinks were evaluated for their acidogenicity. 10% sucrose and 10% sorbitol solutions were used as positive and negative controls, respectively. The minimum pH achieved for DE=5.5, 14.0 and 18.5 was 5.83±0.30, 5.67±0.24 and 5.71±0.29, respectively, and were significantly higher as compared with that for 10% sucrose (5.33±0.17). The area under the curve was the least for DE=5.5 (12.03±4.64), followed by DE=18.5 (13.13±8.87) and DE=14.0 (17.35±6.43), but were all significantly smaller as compared with 10% sucrose (24.50±8.64). The minimum pH achieved for the infant drinks was 6.01±0.24, 5.99±0.28 and 5.8±0.19 for the Lemon Barley and Camomile Herbal baby drink, Mixed Citrus and Hibiscus baby drink, and Infant Milk, respectively. It was concluded that though maltodextrins appeared to be significantly less acidogenic than 10% sucrose, they can lead to a substantial drop in plaque pH and may, therefore, have a potential to cause demineralisation of enamel.

IONIC AND NON-IONIC CONTRAST AGENT-MEDIATED ENDOTHELIAL INJURY. Quantitative analysis of cell proliferation during endothelial repair

Purpose: To quantitatively evaluate endothelial injury in vivo and to assess the time course of cellular repair after endothelial cell exposure to ionic and non-ionic contrast media. Material and Methods: Local changes at the cellular level following intraaortic injection of 1 ml of the ionic contrast agent ioxithalamate or 1 ml of the non-ionic contrast agent iomeprol, each with an iodine content of 300 mg/ml, were investigated using rat endothelium as an in vivo model. A sorbitol solution iso-osmolar to iomeprol served as control. Quantitative analysis of endothelial changes by autoradiography of 3H-thymidine-labeled endothelial cells was assessed after 3, 5 and 10 days, determining the 3H-thymidine index and the DNA synthesis rate. Results: Ioxithalamate showed a clear harmful effect on the endothelium, with an elevated 3H-thymidine index of 7.68% on day 3 and 6.89% on day 5, versus 2.97% on day 3 and 2.55% on day 5 for iomeprol and 2.29% on day 3 and 1.91% on day 5 for the control. Conclusion: Ionic contrast agents lead to reversible transient focal endothelial cell injury. No such side effect was detectable for non-ionic contrast agents.

Ionic and non-ionic contrast agent-mediated endothelial injury: Quantitative analysis of cell proliferation during endothelial repair

To quantitatively evaluate endothelial injury in vivo and to assess the time course of cellular repair after endothelial cell exposure to ionic and non-ionic contrast media. Local changes at the cellular level following intraaortic injection of 1 ml of the ionic contrast agent ioxithalamate or 1 ml of the non-ionic contrast agent iomeprol, each with an iodine content of 300 mg/ml, were investigated using rat endothelium as an in vivo model. A sorbitol solution iso-osmolar to iomeprol served as control. Quantitative analysis of endothelial changes by autoradiography of 3H-thymidine-labeled endothelial cells was assessed after 3, 5 and 10 days, determining the 3H-thymidine index and the DNA synthesis rate. Ioxithalamate showed a clear harmful effect on the endothelium, with an elevated 3H-thymidine index of 7.68% on day 3 and 6.89% on day 5, versus 2.97% on day 3 and 2.55% on day 5 for iomeprol and 2.29% on day 3 and 1.91% on day 5 for the control. Ionic contrast agents lead to reversible transient focal endothelial cell injury. No such side effect was detectable for non-ionic contrast agents.

Turgor pressure regulation and the orientation of cortical microtubules in Spirogyra cells.

Microtubules (MTs) of cells of Spirogyra sp. were depolymerized by treatment with amiprophos-methyl (APM) for 1 h and then reorganized in 0.30 M mannitol solution. The reorganized MTs after 1.5 h incubation showed an oblique/longitudinal orientation and then became transversely oriented as the incubation was prolonged. During this incubation, the osmotic pressure of cells was measured by the plasmolysis method. The cell osmotic pressure increased with time. The calculated turgor pressure at 1.5 h was 0.11 M (mannitol equivalent) and, at 13.5 h, 0.25 M. Similar changes in MT orientation and recovery of the turgor pressure were also observed in 0.30 M sorbitol solution. These results suggest that the MT orientation may be correlated with the turgor pressure. Among fresh water algae sensitive to a saline environment, this Spirogyra was the first species shown to have a turgor regulating mechanism, although the recovery of turgor pressure was incomplete. The recovery of turgor pressure in mannitol solutions was also observed without APM treatment.

Different cytoplasmic calcium contents among three species of Characeae.

Internodal cells of three species of Characeae, Nitella flexilis, Nitella axilliformis and Chara corallina, were analyzed for the contents of Ca(2+ )and Mg(2+) in the cytoplasm. To avoid contamination of Ca(2+) from the cell wall and vacuole, the vacuolar sap was replaced with a sorbitol solution containing Sr(2+) by the vacuolar perfusion method after the cell had been treated with Sr(2+). No significant difference in the cytoplasmic content of Mg(2+) was found among three species of Characeae, but significant differences in the cytoplasmic content of Ca(2+) were observed among them. The cytoplasmic Ca(2+) content of N. flexilis was 2.0 times that of N. axilliformis and 3.3 times that of C. corallina. The cytoplasmic drop was furthermore separated into two fractions: a chloroplast-free fraction and a chloroplast fraction. In the chloroplast-free fraction the Ca(2+) content of N. flexilis was 2.3 times that of C. corallina and 2.0 times that of N. axilliformis, while the Mg(2+) content was the same among the three species. In the chloroplast fraction N. flexilis contained about seven times more Ca(2+) and about two times more Mg(2+) than C. corallina. The difference in the cytoplasmic Ca(2+ )content was discussed in relation to the difference in the capacity for the hydration-induced Ca(2+) release existing among the three species.

Two Types of Water Passages in Okra Hypocotyls

Abrasion of okra hypocotyl segments with carborundum enhances the rate of water uptake into segments, while it decreases the response to auxin. Incubation of abraded segments in buffer recovers the decreased response to auxin. In abraded segments, mercuric chloride is found to inhibit auxin-induced cell elongation. When abraded segments were soaked in 0.3M sorbiiol, they maintained the ability to shrink in the presence of mercury. In contrast, when abraded segments were soaked in a 0.1M sorbitol solution, mercury completely suppressed osmotic shrinkage. These results suggest that water flows through at least two types of passages; One, which is resistant to mercury, requires a high osmotic pressure such as that provided by 0.3 M sorbitol. The other, which is vulnerable to mercury, requires a low osmotic pressure for water to pass through it.

Role of sorbitol in manufacturing dried seafood from heated squid meat

SUMMARY: Japanese common squid meat was heat-treated at 80°C for 1 min, cured with 1.0 M sorbitol solution (pH 7.0) at 4°C for 18 h, and dried further at 30°C (60% relative humidity) for 16 h. Osmotic dehydration during the sorbitol curing process and slow moisture vaporization at the initial drying period were observed regardless of the heat denaturation of muscle protein. Simultaneously, lowering the amount of moisture vaporized in the falling rate of the drying period caused a shortening of the total drying time. Furthermore, the shear force of the dried product from heat-treated meat was kept at a lower value by sorbitol curing, although the suppression effect of sorbitol on the hardening of dried meat was lost by protein denaturation. These results are useful for understanding the role of sorbitol in reducing drying time and in eliminating excess hardening of dried squid products.

Water Activity in Sorbitol or Xylitol + Water and Sorbitol or Xylitol + Sodium Chloride + Water Systems at 20 °C and 35 °C

Water activities of aqueous solutions of sorbitol and xylitol, and of these polyols with sodium chloride, were measured and correlated with a simple empirical equation. Parameters for the equation were obtained, and from them, values of water activity were calculated with an average relative deviation of <0.12% for all the systems studied.

Effect of interfacial properties on the drop size distribution of high internal phase ratio emulsions

Interfacial properties of polyoxyethylene(2) oleyl ether and drop size distributions of emulsions prepared with this surfactant are investigated experimentally in this work; 80, 88 and 94% (v) internal phase ratio W/O type emulsions were prepared, where the aqueous phase was 1% sorbitol solution and the oil phase, a 1:1 v/v mixture of surfactant and paraffin oil. Experimental evidence indicated an interaction between the hydrocarbon chains of surfactant molecules and the solvent paraffin oil through van der Waals forces and between the ethoxylate groups and sorbitol, a polyalcohol, in the aqueous phase through hydrogen bonds, notably below the transition temperature. Continuous phase liquid present in the plateau borders was found to act as a reservoir of surface active agents, minimizing the effect of stretching of the film under shear. In cases where the amount of liquid hold up in plateau borders is negligible, the drop size distributions were found to be very sensitive to shearing rate. Interplay between the interfacial shear viscosity and the interfacial tension was found to control the rate of coalescence of drops less than 0.48 μm only in the case of 94% emulsions, corresponding to maximum stretching of interfacial area. In other cases, interfacial film stability seems to control the rate of coalescence.

Mechanosensory ion channels in Chara: the influence of cell turgor pressure on touch-activated receptor potentials and action potentials

Chara cells produce receptor potentials (RPDs) in response to mechanical stimulation. We have used a mechanostimulatory device to compare characteristics of touch-activated RPDs and action potentials (APs) when cell turgor pressure was changed. The device delivered a series of mechanical stimulations of increasing energy (F0.5, F1, F2, F3, F4, F5 and F6). Cells were alternately stimulated in artificial pondwater (APW) and a sorbitol series, in long-term experiments, involving up to six solution changes. The calculated cell turgor pressures were about 0.6 MPa (APW), and 0.49 MPa, 0.37 MPa, 0.24 MPa and 0.12 MPa in 50, 100, 150 and 200 mM sorbitol–APW, respectively. In other experiments, cells were pre-conditioned in the sorbitol solutions, and then transferred to APW. All cells were allowed long recovery periods (40–60 min) after APs or solution transfers. Only small changes in cell conductance were observed in I–V and G–V analysis of unstimulated cells after reducing turgor pressure from 0.59 MPa to 0.24 MPa. In APW, the RPDs increased in amplitude and duration with increased stimulus energy until the threshold RPD was reached, and an AP was triggered, usually between stimulus F4 and F5. Cells with decreased turgor pressure became more sensitive to stimulation, giving threshold RPDs or APs with smaller stimulus (e.g. between F0.5 and F3). Conversely, an increase in cell turgor pressure (return to APW) led to a decrease in sensitivity to stimulus. When turgor pressure was greatly decreased (to 0.12 MPa), some cells became unresponsive or gave unusual responses. However, only the mechanical part of the touch response was affected by changing the cell turgor pressure. The mean amplitudes of the subthreshold and threshold RPD (that triggers the AP), and of the touch-activated APs, were independent of cell turgor pressure, although action potentials had smaller amplitude when turgor was reduced to about 0.12 MPa. The amplitude of the subthreshold RPD was close to 20 mV, and the amplitude of the threshold RPD was close to 50 mV, in all cells. If tension of the cell wall–plasma membrane–cytoskeleton complex decreased along with decreased cell turgor pressure, a given stimulus could stretch the complex to a greater extent, resulting in activation of more mechanosensory channels. The effect on the RPD of changes in cell turgor pressure is discussed in relation to the mechanical properties of the cell wall–plasma membrane–cytoskeleton complex.

Chroloplast CuZn-superoxide dismutase and catalase are earliest targets of osmotic stress in lettuce plants.,Chroloplast CuZn-superoxide dismutase and catalase are earliest targets of osmotic stress in lettuce plants.

Early biochemical events of osmotic stress occurring in lettuce (Lactucta sativa L.) leaves were investigated in order to elucidate the mechanisms of drought-induced damages in plants. Osmotic stress was given to 3-4 week-old water-cultured lettuce plants by transferring them into sorbitol solutions for limiting water uptake in roots. A mild stress (0.25 M sorbitol, 100 µmol/m2/s white light), which did not wilt leaves up to 4 h, enhanced the level of the methylviologen-and-light-mediated monodehydroascorbate radical in leaves in 1 h, as determined by in vivo ESR. At the same time, superoxide dismutase (SOD) activity in leaves was decreased by 40%. The activity decrease was mostly attributed to the inactivation of chloroplastic (Cp) CuZnSOD, as judged by electrophoresis/activity staining. Cytosolic CuZnSOD was much less affected by the same treatment. Sorbitol did not inhibit SOD activity in vitro. Inactivation of Cp-SOD in leaves required light. At the concentration higher than 0.5 M, catalase also was inactivated in 1 h. Thylakoid-bound ascorbate peroxidase, MDA reductase and Cp-electron transport chain (H2O to NADP+) were not affected by a 1 M sorbitol treatment up to 4 h. These results indicate that Cp-CuZnSOD is the specific and primarily inactivated target and catalase is the secondly sensitive one. Inactivation of these enzymes would lead to oxidative damages in droughted leaves.

Effect of sorbitol on moisture transportation and textural change of fish and squid meats during curing and drying processes

SUMMARY: Atka mackerel (Am) and Japanese common squid (Sq) meats were cured in 0.5–1.5 M sorbitol solutions (pH 7.0) and dried at 30°C (relative humidity, 60%), and the effect of sorbitol on the moisture transportation and textural change during the curing and drying processes was investigated. With an increase in sorbitol permeated through samples, the moisture contents decreased by 52% (Am) and 42% (Sq) by curing in 1.5 M sorbitol solution. When the cured meats were dried, slow moisture vaporization occurred at the initial drying period, and the critical moisture content significantly decreased with an increase in the sorbitol content of the cured meats. Further, the hardening of the dried products was effectively suppressed by sorbitol curing. These effects of sorbitol would contribute to the reduction of drying time and particularly the elimination of the excess hardening of dried fish products.

A kinetic model for turgor loss in red cabbage cells during mild heat treatment

Summary Turgor changes in red cabbage leaves (Brassica oleracea L. covar. Capitata Alef. var. rubra DC.) due to mild heat treatments were measured in the epidermal and first subepidermal cell layers with the pressure probe technique. After an equilibration time in a sorbitol solution of equal water potential, cabbage discs were immersed in solutions heated to 53 °C and 65 °C for different time intervals. Turgor loss at both temperatures could be described by a first order degradation model. This could be due to the increased permeability of membranes at higher temperatures, resulting in passive efflux of solutes and an irreversible reduction of cell turgor well before membranes are completely destroyed. The residual turgor (at t = ∞) for the 53 °C treatment was significantly different from zero. Assuming an Arrhenius type model for the temperature dependency of the rate constant k, the activation energy (Ea = 41 kJ · mol-1) and reference rate constant (kref = 1.53 min-1 for a reference temperature Tref = 323 K) were calculated for the turgor loss model in the epidermal cell layer. In the second cell layer, a time shift of the commencement of turgor decrease could be observed at the lower processing temperature. Temperature profiles at different locations in the cabbage disc were calculated by use of a finite element model and related to turgor loss observations.

Behavior of κ-carrageenan in glycerol and sorbitol solutions

The solubility of κ-carrageenan in low water-content solvents is important in food applications where complete solubilization is required for proper development of structure and rheology. The effect of glycerol and sorbitol on the gelation and conformational helix transition of κ-carrageenan was studied using rheology and optical rotation. Glycerol/water solutions from 0–100 wt% glycerol and sorbitol solutions from 0–100% saturation were studied over the temperature range 0–90°C. The results were analyzed in terms of solvent solubility parameters, water chemical potential, and solvent dielectric constant. Effective cohesive energy density parameters could not be inferred for the carrageenan, but the gelation temperature could be correlated with solvent dielectric constant. Hydrogen bonding interactions control the carrageenan helix formation. The cohesive energy density as a measure of solvent quality accounts for hydrogen bonding but not Coulombic interactions, and the Coulombic interactions scale on dielectric constant. This indicates the dominant role of electrostatics on the gelation process.

Effect of solvent quality and ions on the rheology and gelation of κ-carrageenan

The rheology and conformational helix transition of κ-carrageenan in aqueous solutions of glycerol and sorbitol at low water activity are studied. Carrageenan forms a hydrated gel in water but a weakly flocculated network of partially hydrated particles in glycerol. The melting transitions of carrageenan in glycerol/water solutions show a single peak in the complex moduli at low glycerol concentrations, and two peaks when the glycerol concentration is higher than 40% (w/w). These are thought to be due to the breakage of hydrogen bonds (low temperature peak) and calcium ion dissociation (high temperature peak). The helix–coil transition is shifted to higher temperatures in solutions with higher glycerol or sorbitol content. The temperature of the conformational transition corresponds with that of gelation for all samples. However, there is more hysteresis between the cooling and heating curves (for both OR and rheology) at high water content. This suggests that gelation occurs through helix aggregation in water but the lower solubility of carrageenan results in a more random network of helices in low water activity solvents.

Carbohydrate metabolism in a heat‐girdled maize source leaf

ABSTRACTHeat‐girdling in maize leaves was used for blocking assimilate export and producing alterations in carbohydrate metabolism. A rapid drop (&lt; 24 h) in CO2 fixation and a large increase of sucrose and starch content were observed. Reduction in photosynthetic assimilation was not due to stomatal limitation since the girdled leaves remained turgid and their photosynthetic rate was not restored by 4% CO2. After 24 h, the girdled leaves became red through accumulation of anthocyanins and reduction of chlorophylls. A possible relationship between carbohydrate accumulation in girdled leaves and gene expression was examined through transcript levels of the ribulose‐1,5‐bisphosphate carboxylase oxygenase small‐subunit (rbcS), the leaf‐specific ADPglucose pyrophosphorylase small‐subunit (Agp‐l2), and Bz1, an anthocyanin pathway‐specific gene. The mRNA levels in girdled leaves were also compared with those in excised leaves placed on sucrose or sorbitol solutions. rbcS mRNA disappeared 8 h after the girdling treatment and after 1 day on sucrose. Agp‐l2 expression was reduced by two‐thirds with girdling or sucrose feeding while Bz1 expression was strikingly enhanced by both treatments. Thus, carbohydrate accumulation produced a short‐term feedback inhibition of photosynthesis and some long‐term modifications in gene expression.

Stability of Extemporaneous Norfloxacin Suspension

The stability of norfloxacin as extemporaneous suspensions compounded from two brands of film-coated tablets (formulas I and II) was studied. The vehicle consisted of tragacanth, saccharin sodium, sorbitol solution, glycerin, paraben concentrate, peppermint spirit BP, purified water, and syrup USP. The final concentration of norfloxacin in the suspensions was 20 mg/ml. Formulas I and II were chemically stable for 28 days when stored in amber glass bottles at ambient temperature; however, their physical characteristics were different.

In vitro investigation of the effect of various isotonic substances in parenteral emulsions on human erythrocytes

The hemolytic behaviour of human erythrocytes in parenteral emulsions containing various isotonizing substances (xylitol, sorbitol and glycerol) was studied. It was found that complete hemolysis of human erythrocytes occurred in parenteral emulsions with isotonic or isosmotic concentration of glycerol after 5 min, whereas emulsions which contained an isotonic concentration of xylitol or sorbitol did not show any hemolysis after 40 min. Conversely, formulations with different concentrations of glycerol in an isotonic solution of sorbitol did not show any hemolytic behaviour after 40 min. It appeared that all the hemolytic phenomena encountered in glycerol were of an isotonic character since hemolysis was totally prevented by the inclusion of an isotonic concentration of sorbitol. According to these in vitro results it seems that glycerol, a commonly used substance in commercial parenteral emulsions, may not be the best isotonizing substance.