Sucrose Concentration In Solution Research Articles

Volumetric, ultrasonic and viscometric studies of solute–solute and solute–solvent interactions of l-threonine in aqueous-sucrose solutions at different temperatures

Densities, ρ of solutions of l-threonine in aqueous-sucrose solvents 5%, 10%, 15%, and 20% of sucrose, w/w in water at T=(293.15, 298.15, 303.15, 308.15, 313.15, and 318.15)K; and ultrasonic speeds, u and viscosities, η of these solutions at 298.15, 303.15, 308.15, 313.15, and 318.15K were measured at atmospheric pressure. From these experimental results, the apparent molar volume, Vϕ, limiting apparent molar volume, Vϕ∘ and the slope, Sv, apparent molar compressibility, Ks,ϕ, limiting apparent molar compressibility, Ks,ϕ∘ and the slope, Sk, transfer volume, Vϕ,tr∘, transfer compressibility, Ks,ϕ,tr∘, limiting apparent molar expansivity, Eϕ∘, Hepler’s constant, (∂2Vϕ∘/dT2), Falkenhagen coefficient, A, Jones–Dole coefficient, B and hydration number, nH have been calculated. The results have been interpreted in terms of solute–solvent and solute–solute interactions in these systems. The Gibbs energies of activation of viscous flow per mole of solvent, Δμ1∘# and per mole of solute, Δμ2∘# were also calculated and discussed in terms of transition state theory. It has been observed that there exist strong solute–solvent interactions in these systems and these interactions increase with increase in sucrose concentration in solution.

Sodium-dependent activity of aquaporin-1 in rat glioma cells: a new mechanism of cell volume regulation

Cell volume controls many functions and is itself regulated. To study cell volume regulations, the mean volume of C6-BU-1 rat glioma cells was electronically measured under isotonic and anisotonic conditions. Two isotonic solutions were used containing either normal (solution 1) or low (solution 2) NaCl. Anisotonicity was induced by changing NaCl or sucrose concentrations in solutions 1 and 2, respectively. The cells behaved like perfect osmometers when the tonicity was increased. In contrast, just after hypotonic challenges, the cell volume was smaller than that predicted by a perfect osmometer. This deviation reveals a new mechanism, which we call the volume increase limitation (VIL). When hypotonicity was induced by decreasing NaCl, a classical slow regulatory volume decrease (RVD) was also observed in addition to VIL. The cells expressed aquaporin-1 sensitive to HgCl(2) and decreased by siRNA, which both reduced fast volume changes. In this study, we show that: (1) RVD is proportional to the change in external Cl(-) concentration and is inhibited by Cl(-) channel and K(+)-Cl(-) cotransporter blockers; (2) cell swelling due to the influx of H(2)O through aquaporins shows rectification with decreasing osmolarity and is sensitive to the internal Na(+) concentration; (3) VIL is linearly related with hypotonicity and is abolished in solutions 1 and 2 by the Na(+) ionophore monensin and in solution 1 by the Na(+)-K(+) ATPase inhibitor ouabain. These results suggest that VIL is triggered by the decrease in internal Na(+) caused by hyponatrema and cell swelling. In addition to RVD, VIL should protect cells during hyposmotic stress.

Effect of food quality on the body temperature of wasps ( Paravespula vulgaris)

Body surface temperature of individually marked wasps ( Paravespula vulgaris, Vespidae, Hymenoptera) was measured by infrared thermography during repeated visits to a feeding bowl without injuring them or disturbing their behavior. Wasps were fed 0.5, 1 and 2 mol/l sucrose solution at two ambient temperatures. Thoracic temperature varied significantly in dependence on food quality (sucrose concentration of solution). At the higher ambient temperatures of 26.1–30.2°C mean thoracic surface temperatures from different experiments were 35.3 and 38.0°C when the wasps took a 0.5 mol/l sucrose solution, 37.0, 38.7 and 38.7°C when they took a 1 mol/l solution, and 39.1°C when they took a 2 mol/l sucrose solution. At the lower ambient temperatures of 17.6–21.0°C thoracic temperatures were lower but the effect of different sucrose concentrations was similar: 34.7°C with a 0.5 mol/l and 36.1°C with a 1 mol/l sucrose solution. The concentration effect amounted to about 10–25% of the whole variability of thorax temperature. By contrast, the temperatures of the head and abdomen did not follow the changes in thorax temperature according to changes in sucrose concentration closely, which suggests that the pattern of haemolymph circulation may have changed after landing, during the wasps' stay at the feeder. At initial landing at the feeders thoracic temperatures where equal to (three of eight tests) or lower (five of eight tests) than at final departure. The correlation of thorax temperature with food quality probably reflects the wasps' level of excitement and motivation to collect the food, which allows them to balance energetic investment with profitability of foraging and the needs of flight muscle performance and motility.

Microcalorimetric control of microbiological processes: I. Analytical detection of glucose and some other carbohydrates

Microcalorimetric methods have been developed for continuous analytical control of glucose, lactose and sucrose concentrations in solutions in biotechnological processes. The methods are based on the Malprade reaction. The carbohydrate concentrations were detected on a flow-mix microcalorimeter. The accuracy of measurements of the carbohydrate concentration (2–4 mM) in solution is 1–2%. Other components common to biotechnological solutions (amino acids, ammonium ions, urea and acetate) have virtually no influence on the results.