Osmotic Solutes Research Articles

Efficiently manufacturing ectoine via metabolic engineering and protein engineering of L-2,4-diaminobutyrate transaminase

Ectoine, so-called tetrahydropyrimidine, is an important osmotic adjustment solute and widely applied in cosmetics and protein protectant. Some attempts have been made to improve the ectoine productivity. However, the strains with both high ectoine production capacity and high glucose conversion were still absent so far. Aim to construct a strain for efficiently producing ectoine, ectoine synthetic gene cluster ectABC from Pseudomonas stutzeri was overexpressed in E. coli BL21 (DE3). The ection production was improved by 382 % (ectoine titer increased from 1.73 g/L to 8.33 g/L) after the rational design of rate-limiting enzyme L-2,4-diaminobutyrate transaminase EctBps (protein engineering) combined with the metabolic engineering that focused on the enrichment and conversion of precursors. The final strain YW20 was applied to overproduce ectoine in fed-batch fermentation and yield 68.9 g/L of ectoine with 0.88 g/L/h of space-time yield and the highest glucose conversion reported [34 % (g/g)]. From the fermentation broth, ectoine was purified with 99.7 % purity and 79.8 % yield. This study successfully provided an engineered strain as well as an efficient method for the industrial bio-synthesis and preparation of ectoine.

Analytical Modeling of the Functioning of the Pulsatory Liposome

In this paper the analytical solutions of the differential equations are presented. These equations describe the pulsatory liposome dynamics. We consider a unilamellar liposome filled with an aqueous solution of osmotic solute inserted in a hypotonic aqueous medium. Due to the osmosis process the liposome has a cyclic evolution. The lipid vesicle swells to a critical size, when a transbilayer pore suddenly appears. Part of the internal solution leaks through this pore. The liposome relaxes and returns to the initial size. The swelling starts again and the liposome goes through a periodical process. The swelling of the liposome is described by a differential equation. All the processes which contribute to the liposome relaxing and its coming back to the initial size are described by three differential equations. Based on some analytical methods, we solve these equations and their explicit solutions are validated by comparing with previous study numerical results.

Simulation of pulsatory liposome working using a linear approximation for transmembrane pore dynamics

This paper presents an analytical solution of the differential equations describing the pulsatory liposome dynamics. We consider a unilamellar liposome filled with an aqueous solution of osmotic solute inserted in a hypotonic aqueous medium. Due to the osmosis process the liposome has a cyclic evolution. The lipid vesicle swells to a critical size, at which point a transbilayer pore suddenly appears. Part of the internal solution leaks through this pore. The liposome relaxes and returns to the initial size. The swelling starts again and the liposome goes through a periodical process. The swelling of the liposome is described by a differential equation. The appearance of the pore changes the evolution of the liposome. The internal solution comes out through the pore and the liposome starts its deflation (relaxation). The evolution of the pore has two phases: first, the radius of the pore increases to its maximum value, then the radius decreases until it disappears, and the liposome reaches its initial size. During each cycle, the liposome will release a quantity (a pulse) of the solution from its interior. All the processes which contribute to the liposome relaxing and its coming back to the initial size are described by three differential equations. This system of differential equations can be integrated using numerical methods. The functions – which model our biological engine in three stages, are as follows: R(t) - the liposome radius, r(t) - the pore radius, C(t) - solute concentration, Q(t) - the osmotic solute amount inside the liposome. The graphs representing these functions contain important linear portions, which suggested a solution using analytical methods. Based on some analytical methods, we solve these equations, and their explicit solutions are validated by comparing with numerical results of previous studies.

Waterlogging restricted cotton fiber elongation by reducing osmolyte accumulation and cell wall biosynthesis

Waterlogging severely threatens the formation of cotton fiber quality, especially the length. However, the underlying mechanism is still incompletely understood. Here, the experiment (control: soil relative water content at (75 ± 5)%; treatment: waterlogging for 6 days) was conducted during the flowering and boll forming stage using two upland cotton cultivars (Dexiamian 1 and Yuzaomian 9110) to investigate the effects of waterlogging on fiber development from both transcriptomic and physiological levels. The transcriptome analysis of 10 days post anthesis cotton fiber showed that waterlogging significantly regulated the expression of genes associated with fiber elongation events including osmotic solutes accumulation, fiber cell wall biosynthesis, and cell wall remodeling and loosening. Waterlogging decreased the sucrose input into cotton fiber, resulting in reduced sucrose and hexose contents. Under waterlogging, the accumulation of malate and K+ in both cultivars was reduced by decreasing phosphoenolpyruvate carboxylase (PEPC) activity and potassium transporter genes (GhPOT) expression, respectively. Thus, the total concentration of osmolytes was reduced, which dampened cotton fiber elongation. Due to reduced sucrose synthase activity and uridine diphosphate glucose content, the cellulose biosynthesis was limited, leading to decreased fiber cell wall accumulation, which was adverse to fiber elongation. Besides, genes responsible for cell wall remodeling and loosening, including xyloglucan endotransglucosylase/hydrolase genes (GhXTH), α-expansin genes (GhEXPA), and pectin methylesterase genes (GhPME) were also responsive to waterlogging, but in different ways between cultivars. Overall, the shortened cotton fiber could be attributed to reduced osmolytes accumulation and cell wall biosynthesis, whilst the effects of waterlogging on cotton fiber cell wall loosening require further exploration.

Exogenous 5-Aminolevulinic Acid Promotes Osmotic Stress Tolerance of Walnuts by Modulating Photosynthesis, Osmotic Adjustment and Antioxidant Systems

The walnut (Juglans regia L.) is an important economic tree worldwide, often cultivated in arid and semiarid regions. Improving the drought tolerance is of significance for walnut growth, production, and economic effectiveness. 5-Aminolevulinic acid (ALA) is a novel plant growth regulator which raises plant tolerance to various stressful conditions. Here, foliage application of ALA was carried out to uncover its effect on walnuts under polyethylene glycol (PEG) 6000-stimulated osmotic stress. Our results displayed that exogenous ALA greatly promoted the chlorophyll content, photochemical activities, and gas exchange in walnuts under osmotic stress. ALA led to a considerable accumulation of compatible osmotic solutes, enabling walnuts to maintain osmotic equilibrium against drought stress. Furthermore, ALA alleviated the reactive oxygen species (ROS) damages on osmotically stressed walnuts through enhancing the antioxidant enzyme activities, as well as decreasing the ROS and malondialdehyde (MDA) content. The relative water content (RWC) in the ALA-treated leaves was higher than that of PEG-stressed, while the RWC in the substrate of ALA treatment was significantly lower than that of the PEG-stressed, further suggesting that ALA promotes plant water uptake from the substrate under osmotic stress. These demonstrate that ALA improves the photosynthesis, osmotic adjustment, antioxidant systems and, consequently, the walnuts’ drought tolerance.

Differences in Organic Solute and Metabolites of Leymus chinensis in Response to Different Intensities of Salt and Alkali Stress.

To explore differences in the physiological metabolic response mechanisms of grassland perennial plants to different intensities of salt-alkali stress, we employed GC-MS to identify the metabolome of perennial rhizome-saline-tolerant Leymus chinensis (L. chinensis). L. chinensis reduced stress damage by accumulating osmotic solutes during salt-alkali stress, although the types of accumulated solutes varied with stress and concentration gradients. Soluble sugars increased only under mild salt-alkali stress. Under salt and mild alkali stress, amino acids increased. Under severe salt-alkali stress, organic acids increased. Betaine increased as a typical osmolute under salt-alkali stress. Metabolic analysis identified 20 metabolites, including 4 amino acids, 6 sugars, and 10 organic acids. The majority of them increased in response to stress. Under mild salt stress, the metabolites included glycine and proline. Under mild alkali stress, they primarily consisted of sugars such as isomaltose and lactulose, whereas under severe salt-alkali stress, they primarily consisted of organic acids such as citric acid and isocitric acid. Pathway analysis showed that six pathways were affected. Glycine, serine, and threonine metabolism was affected under mild salt stress. Alanine, aspartate, and glutamate metabolism and butanota metabolism were affected under mild alkali stress, while energy metabolism pathways, such as the TCA cycle and glyoxylate and dicarboxylate metabolism, were affected under severe salt-alkali stress. The results indicate the importance of betaine in stress resistance and the significance of organic acid in severe salt stress, and they also demonstrate that energy supply was one of the key mechanisms in response to severe salt-alkali stress.

Mathematical Description of the Functioning of the Pulsatory Liposome

We consider a liposome filled with the aqueous solution of an osmotic solute enclosed in a large water bath. Due to osmotic pressure, it works according to a sequence of cycles with two stages. In the first stage, the lipid vesicle with a certain input concentration of the osmotic substance is swelling up in an osmotic process until it reaches a size, when one pore is formed on its surface. The second stage follows, where the vesicle content is partially eliminated through the pore to induce a decrease in the vesicle volume up to its original size. If we take into account that the pore has two stages in its evolution, then the relaxing stage may be divided into two new stages. The swelling of the liposome is described by a differential equation. All the processes which contribute to the vesicle relaxing and its return to the initial size are described by three differential equations.

Potassium application enhances drought tolerance in sesame by mitigating oxidative damage and regulating osmotic adjustment.

Potassium (K) is known for alleviating the negative effects of abiotic stresses on plants. To explore the functions of K in controlling reactive oxygen species (ROS), antioxidant activities, and osmoregulation in sesame under drought stress, a pot experiment was conducted with three K levels (0, 60, and 120kg ha-1, recorded as K0, K1, and K2, respectively) and exposed to well-watered (WW, 75% ± 5% soil relative water content) and drought-stressed (DS, 50% ± 5% soil relative water content) conditions. The results showed that DS stimulated the production of ROS such as increased hydrogen peroxide (H2O2), leading to lipid peroxidation as characterized by higher malondialdehyde (MDA) and, consequently, resulting in the decline in relative water content (RWC) and photosynthetic pigments as compared with WW plants. These adverse effects were exacerbated when drought stress was prolonged. Concurrently, K application alleviated the magnitude of decline in the RWC, chlorophyll a, and chlorophyll b, and plants applied with K exhibited superior growth, with the optimal mitigation observed under K2 treatment. Additionally, DS plants treated with K exhibited lower lipid peroxidation, higher antioxidant activities, and increased osmotic solute accumulation in comparison with plants under K deficiency, which suggested that exogenous K application mitigated the oxidative damages and this was more prominent under K2 treatment. Noteworthily, proline and soluble protein, respectively, dominated in the osmotic regulation at 3 and 6 days of drought stress according to the analysis of the quantitative comparison among different osmotically active solutes. Based on the correlation of the aforementioned traits and the analysis of variance on the interaction effects of drought stress and potassium, we propose that superoxide dismutase (SOD), glutathione reductase (GR), and MDA could be critical indicators in balancing ROS detoxification and reproduction. In summary, our studies suggest that optimized K application keeps a balance between the production of antioxidants and ROS and simultaneously affects osmoregulation to alleviate the damage from drought stress.

Identification of Alkaline Salt Tolerance Genes in Brassica napus L. by Transcriptome Analysis.

Soil salt alkalization is one major abiotic factor reducing the productivity of crops, including rapeseed, an indispensable oil crop and vegetable. The mechanism studies of alkali salt tolerance can help breed highly resistant varieties. In the current study, rapeseed (B. napus) line 2205 exhibited more tolerance to alkaline salt than line 1423 did. In line 2205, the lesser plasma membrane damage index, the accumulated osmotic solute, and higher antioxidant enzyme activities contributed to alkaline tolerance. A more integrated mesophyll-cell structure was revealed under alkali salt stress by ultrastructure observation in line 2205, which also implied a lesser injury. Transcriptome analysis showed that more genes responded to alkaline salt in line 2205. The expression of specific-response genes in line 1423 was lower than in line 2205. However, most of the specific-response genes in line 2205 had higher expression, which was mainly enriched in carbohydrate metabolism, photosynthetic processes, ROS regulating, and response to salt stress. It can be seen that the tolerance to alkaline salt is attributed to the high expression of some genes in these pathways. Based on these, twelve cross-differentially expressed genes were proposed as candidates. They provide clues for further analysis of the resistance mechanism of rapeseed.

The Osmoprotectant Switch of Potassium to Compatible Solutes in an Extremely Halophilic Archaea Halorubrum kocurii 2020YC7.

The main osmoadaptive mechanisms of extremely halophilic archaea include the “salt-in” strategy and the “compatible solutes” strategy. Here we report the osmoadaptive mechanism of an extremely halophilic archaea H. kocurii 2020YC7, isolated from a high salt environment sample. Genomic data revealed that strain 2020YC7 harbors genes trkA, trkH, kch for K+ uptake, kefB for K+ output, treS for trehalose production from polysaccharide, and betaine/carnitine/choline transporter family gene for glycine betaine uptake. Strain 2020YC7 could accumulate 8.17 to 28.67 μmol/mg protein K+ in a defined medium, with its content increasing along with the increasing salinity from 100 to 200 g/L. When exogenous glycine betaine was added, glycine betaine functioned as the primary osmotic solute between 200 and 250 g/L NaCl, which was accumulated up to 15.27 mg/mg protein in 2020YC7 cells. RT-qPCR results completely confirmed these results. Notably, the concentrations of intracellular trehalose decreased from 5.26 to 2.61 mg/mg protein as the NaCl increased from 50 to 250 g/L. In combination with this result, the transcript level of gene treS, which catalyzes the production of trehalose from polysaccharide, was significantly up-regulated at 50–100 g/L NaCl. Therefore, trehalose does not act as an osmotic solute at high NaCl concentrations (more than 100 g/L) but at relatively low NaCl concentrations (50–100 g/L). And we propose that the degradation of cell wall polysaccharide, as a source of trehalose in a low-salt environment, may be one of the reasons for the obligate halophilic characteristics of strain 2020YC7.

Activity-induced propulsion of a vesicle

Modern biomedical applications such as targeted drug delivery require a delivery system capable of enhanced transport beyond that of passive Brownian diffusion. In this work, an osmotic mechanism for the propulsion of a vesicle immersed in a viscous fluid is proposed. By maintaining a steady-state solute gradient inside the vesicle, a seepage flow of the solvent (e.g. water) across the semipermeable membrane is generated, which in turn propels the vesicle. We develop a theoretical model for this vesicle–solute system in which the seepage flow is described by a Darcy flow. Using the reciprocal theorem for Stokes flow, it is shown that the seepage velocity at the exterior surface of the vesicle generates a thrust force that is balanced by the hydrodynamic drag such that there is no net force on the vesicle. We characterize the motility of the vesicle in relation to the concentration distribution of the solute confined inside the vesicle. Any osmotic solute is able to propel the vesicle so long as a concentration gradient is present. In the present work, we propose active Brownian particles (ABPs) as a solute. To maintain a symmetry-breaking concentration gradient, we consider ABPs with spatially varying swim speed, and ABPs with constant properties but under the influence of an orienting field. In particular, it is shown that at high activity, the vesicle velocity is $\boldsymbol {U}\sim [K_\perp /(\eta _e\ell _m) ]\int \varPi _0^{swim} \boldsymbol {n}\,{\rm d}\varOmega$ , where $\varPi _0^{swim}$ is the swim pressure just outside the thin accumulation boundary layer on the vesicle interior surface, $\boldsymbol {n}$ is the unit normal vector of the vesicle boundary, $K_\perp$ is the membrane permeability, $\eta _e$ is the viscosity of the solvent, and $\ell _m$ is the membrane thickness.

Bacillus amyloliquefaciens Rescues Glycyrrhizic Acid Loss Under Drought Stress in Glycyrrhiza uralensis by Activating the Jasmonic Acid Pathway.

Drought is a major factor limiting the production of the perennial medicinal plant Glycyrrhiza uralensis Fisch. (Fabaceae) in Northwest China. In this study, 1-year-old potted plants were inoculated with the strain Bacillus amyloliquefaciens FZB42, using a gradient of concentrations (CFU), to test for microbe-induced host tolerance to drought condition treatments in a greenhouse experiment. At the concentration of 108 CFU ml–1, FZB42 had significant growth-promoting effect on G. uralensis: the root biomass was 1.52, 0.84, 0.94, and 0.38 times that under normal watering and mild, moderate, and severe drought stress conditions, respectively. Under moderate drought, the positive impact of FZB42 on G. uralensis growth was most pronounced, with both developing axial and lateral roots strongly associated with indoleacetic acid (IAA) accumulation. An untargeted metabolomic analysis and physiological measurements of mature roots revealed that FZB42 improved the antioxidant system of G. uralensis through the accumulation of proline and sucrose, two osmotic adjustment solutes, and by promoting catalase (CAT) activity under moderate drought stress. Furthermore, significantly higher levels of total flavonoids, liquiritin, and glycyrrhizic acid (GA), the pharmacologically active substances of G. uralensis, were found in the roots of inoculated plants after FZB42 inoculation under all imposed drought conditions. The jasmonic acid (JA) content, which is closely related to plant defense responses and secondary metabolites’ production, was greatly increased in roots after the bacterial inoculations, indicating that FZB42 activated the JA pathway. Taken together, our results demonstrate that inoculation with FZB42 alleviates the losses in production and pharmacological metabolites of G. uralensis caused by drought via the JA pathway’s activation. These results provide a developed prospect of a microbial agent to improve the yield and quality of medical plants in arid and semi-arid regions.

Effects of Drought Stress and Rehydration on Physiological and Biochemical Properties of Four Oak Species in China.

Quercus fabri Hance, Quercus serrata Thunb, Quercus acutissima Carruth, and Quercus variabilis BL are four Chinese oak species commonly used for forestation. To ensure the survival of seedlings, we first need to understand the differences in drought resistance of the four oak species at the seedling stage, and comprehensively evaluate their drought resistance capabilities. The four oak seedlings were divided into drought-rewatering treatment group and well watered samples (control group). For the seedlings of the drought-rewatering treatment group, drought stress lasting 31 days was used, and then re-watering for 5 days. The water parameters, osmotic solutes content, antioxidant enzyme activity and photosynthesis parameters of the seedlings in the two groups were measured every 5 days. Compared with the control group, the relative water content, water potential, net photosynthetic rate, transpiration rate, and stomatal conductance levels of the four oaks all showed a downward trend under continuous drought stress, and showed an upward trend after rehydration. The soluble protein, soluble sugar, proline, peroxidase, superoxide dismutase and catalase content of the four oaks increased first and then decreased under drought stress, and then increased after rehydration. The content of glycine betaine and malondialdehyde continued to increase, and gradually decreased after rehydration. The weight of each index was calculated by principal component analysis, and then the comprehensive evaluation of each index was carried out through the membership function method. The drought resistance levels of the four oak species were as follows: Q. serrata > Q. fabri > Q. variabilis > Q. acutissima.

Metabolic Engineering of Escherichia coli for Ectoine Production With a Fermentation Strategy of Supplementing the Amino Donor

Ectoine, an osmotic pressure-compensated solute, is used in the food, agriculture, medicine, and cosmetics industries due to its ability to protect macromolecules. In this study, an ectoine-producing variant of Escherichia coli, ET08, was genetically constructed by introducing the ectABC gene cluster and eliminating metabolic pathways involving lysine and pyruvate. Medium optimization enhanced ectoine production from 1.87 to 10.2 g/L. Analysis of the transcriptional levels revealed that supplementation with ammonium sulfate enhanced the metabolic flux towards the biosynthesis of ectoine. Furthermore, by optimizing the copy number of ectA, ectB, and ectC, the recombinant E. coli ET11 (ectA:ectB:ectC = 1:2:1) produced 12.9 g/L ectoine in the shake flask and 53.2 g/L ectoine in a fed-batch fermenter, representing the highest ectoine titer produced by E. coli, which has great industrial prospects.

Optimization of maltodextrin (10DE)—Sucrose moderated microwave osmotic dehydration of mango cubes under continuous flow spray mode (MWODS) conditions

AbstractThe process of microwave osmotic dehydration of mango was optimized under continuous flow medium spray conditions (MWODS) with maltodextrin (10DE) moderated sucrose solutions. Optimization was carried out using a response surface methodology with a central composite rotatable (CCRD) design with three input variables at five levels (temperature, 33°C to 66.7°C; sucrose:maltodextrin ratio from 100:0 to 80:20; and solute concentration, 33 to 66.7%). The response parameters used for optimization were moisture loss (ML), solids gain (SG), weight reduction (WR), ML/SG ratio, color and texture values. For each response, RSM models (p < .05) were developed. As expected, all output variables were responsive to process variables and addition of maltodextrin to sucrose was found to have a significant effect on reducing the SG and increasing ML/SG, and total solute concentration had significant effects on ML, SG and quality parameters. The process was optimized by desirability approach and MWODS at 56°C with total osmotic solute 46% concentration and 84:16 sucrose:maltodextrin proportion had the highest desirability value. Selection of constraints was an influential factor as well.Practical ApplicationsOsmotic dehydration (OD) has many advantages, but is a slow process. Carrying out OD in MW environment accelerates the process, enhances moisture loss (ML) and limits the solids gain (SG). The quality of OD foods is related to ML/SG ratio and the MWOD process enhances ML/SG. This can be further enhanced by incorporating high molecular solutes like maltodextrins. This research optimizes the maltodextrin moderated MWOD process under continuous medium flow conditions. The process offers significant potential for reducing the treatment time (to 30 min) and improve the ML/SG ratio. The resulting product can be finish dried, used as intermediate moisture food or frozen (dehydrofreezing).

Alfalfa (Medicago sativa L.) MsCML46 gene encoding calmodulin-like protein confers tolerance to abiotic stress in tobacco.

MsCML46 enhances tolerance to abiotic stresses through alleviating osmotic stress and oxidative damage by regulating the expression of stress-related genes to optimize osmolytes levels and antioxidant enzyme activity in transgenic tobacco. Abiotic stresses are major environmental factors that constraint crop productivity worldwide. Various stimuli regulate intracellular calcium levels and calcium-mediated signal transduction, and cellular responses. Ca2+ signals are perceived by different Ca2+ receptors. Calmodulin-like protein (CML) is one of the best-characterized Ca2+ sensors which shares sequence similarity with highly conserved calmodulin (CaM) ubiquitously expressed in plants. Currently, the molecular and physiological functions of CMLs are largely unknown. In this study, the MsCML46 was characterized in alfalfa (Medicago sativa cv. Zhaodong) under freezing stress. Results showed that MsCML46 was localized to the cytoplasm of Arabidopsis, and its expression was strongly elevated by cold, drought, salt, saline-alkali, and ABA treatments. Overexpressing MsCML46 in tobacco enhanced tolerance to freezing, drought, and salt stresses as evidenced by improved contents of osmotic regulatory solutes and antioxidant enzyme activity but decreased reactive oxygen species (ROS) accumulation. Furthermore, cold, drought, and salt stresses increased the expression of stress-related genes in transgenic tobacco. MsCML46 binds free Ca2+ to promote signal transduction and maintain higher K+/Na+ ratio. In this way, it protects intracellular homeostasis under sodium ion toxicity. These results suggest that MsCML46 plays a crucial role in resisting abiotic stresses and can be exploited in genetic engineering for crops.

The red alga Tsunamia transpacifica (Stylonematophyceae) from plastic drift shows adaptation to its uncommon habitat in ultrastructure and soluble low molecular weight carbohydrate composition

The recently described red alga Tsunamia transpacifica (Stylonematophyceae) was previously isolated from plastic drift found at the pacific coast, but the natural habitat remains unknown. Here, we investigate ultrastructural details and the low molecular weight soluble carbohydrate composition to get further insight into the adaptation to this uncommon habitat. By means of high pressure freeze fixation, followed by freeze substitution, we could detect an up to 2-µm-thick cell wall surrounded by a distinct layer of extracellular polymeric substances (EPS), likely responsible for the adhering capacities of Tsunamia. The central position of the nucleus and multilobed parietal chloroplast, already observed by light microscopy, could be confirmed. The ultrastructure revealed large electron-dense bodies (EB) in the central cytoplasm, likely resembling degradation products of the chloroplast. Interestingly, these structures contained phosphorous and cobalt, and iron was found in smaller rounded electron-dense bodies by electron energy loss spectroscopy (EELS). Accumulation of these elements suggests a high biosorption activity of Tsunamia. Liquid chromatography-mass spectrometry (LC–MS) data showed the presence of two heterosides (floridoside and digeneaside) together with the polyol sorbitol, which are known as organic osmolytes and compatible solutes. Taken together, these are the first observations on ultrastructural details, element storage and accumulation of protective compounds are contributing to our understanding of the ultrastructural and osmotic solute basis for the ability of Tsunamia to thrive on plastic surfaces.

Idaho database of solution thermodynamics

The “Idaho Database of Solution Thermodynamics” (IDST, https://idst.inl.gov/) was created by collecting literature vapor liquid equilibrium (VLE) data in the form of practical osmotic coefficients, ϕm, and solute molal activity coefficients, γB(m), for binary solutions (solute-solvent). These values, corresponding to isothermal vapor pressure measurements, were collated from literature sources to further research involving concentration dependent solution properties. The initial data cohort includes 473 aqueous datasets and 121 non-aqueous datasets from 119 references. This data has been made publicly available in a graphically, tabularly, and machine-readable forms in a variety of concentration and property units.

Glass transition and crystallization of solid model system of jujube slice as influenced by sugars and organic acids

To understand the specific contributions of amorphous sugars and organic acids to the quality of food matrix, the solid model system of jujube slice skeleton (JSS) was firstly established. Effects of fructose (F), glucose (G), malic acid (M) and citric acid (C) on the glass transition temperature (Tg) and crystallization of JSS were studied. JSS-F/G/M/C blends were prepared by osmosis in the solution at a range of 0 ~ 32 g/100 g. Sugars reduced the Tg in the system, structure of JSS-G/M blends was changed from “amorphous glassy” to “amorphous rubbery” by increasing the osmotic solute concentration. Tg was decreased from 50.8 to 14.0 °C when JSS was osmosed in a 4 g/100 g fructose solution. Organic acids induced their crystallization in JSS. The crystallinity of JSS-M immersed in 32 g/100 g osmotic solution concentration was increased from 2% to 75%. Fructose presented greater influence on the adverse quality of jujube slices.

Aquaporin gene transfer for hepatocellular cholestasis

Bile secretion by hepatocytes is an osmotic process. The output of bile salts and other organic anions (e.g. glutathione), through the bile salt transporter BSEP/ABCB11 and the organic anion transporter MRP2/ABCC2, respectively, are considered to be the major osmotic driving forces for water secretion into bile canaliculi mainly via aquaporin-8 (AQP8) channels. The down-regulated canalicular expression of these key solute transporters and AQP8 would be a primary event in the establishment of hepatocellular cholestasis. Recent studies in animal models of hepatocellular cholestasis show that the hepatic delivery of AdhAQP1, an adenovector encoding for the archetypical water channel human aquaporin-1 (hAQP1), improves bile secretion and restores to normal the elevated serum bile salt levels. AdhAQP1-transduced hepatocytes show that the canalicularly-expressed hAQP1 not only enhances osmotic membrane water permeability but also induces the transport activities of BSEP/ABCB11 and MRP2/ABCC2 by redistribution in canalicular cholesterol-rich microdomains likely through interactions with the cholesterol-binding protein caveolin-1. Thus, the hepatic gene transfer of hAQP1 improves the bile secretory failure in hepatocellular cholestasis by increasing both biliary output and choleretic efficiency of key osmotic solutes, such as, bile salts and glutathione. The study of hepatocyte aquaporins has provided new insights into the mechanisms of bile formation and cholestasis, and may lead to innovative treatments for cholestatic liver diseases.