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The integral water capacity (IWC) approach takes into account various soil physical limitations for calculating plant available water. However, the IWC approach cannot distinguish the differences in water uptake between various plants. Therefore, the objectives of this study were i) to modify the approach to include plant physiological properties to redefine the wet and dry ends of the IWC, called [IWC.sub.plant] and ii) to evaluate the performance of the [IWC.sub.plant] approach using experimental data. The restrictions imposed by poor soil aeration and rapid drainage flux were calculated using both soil and plant properties to modify the wet end of the IWC. The soil hydraulic resistance was considered to redefine the dry end of the [IWC.sub.plant]. Based on these approaches, physically meaningful weighting functions were developed for three proposed limiting factors at both ends of the wet and dry ranges of soil. Experimental data were obtained from a greenhouse trial with wheat and canola plants in two soil textures (sandy loam and clay loam) for 2 years. The [IWC.sup.plant] obtained values of 0.202 and 0.205 [m.sup.3] [m.sup.-3] for wheat and 0.189 and 0.194 [m.sup.3] [m.sup.-3] for canola in sandy loam and clay loam soils, respectively. These differences in the [IWC.sub.plant] between wheat and canola in the same soils demonstrate the importance of plant properties to estimate actual plant available water using IWC. These differences would be even more appreciable for root systems with a wider range of different properties. Additional keywords: Critical aeration porosity, flux-based field capacity, soil available water, soil respiration rate, soil hydraulic resistance., Introduction The 'soil-water availability' concept illustrates the ease by which a plant uptakes and utilises soil moisture, and is an important foundation for irrigation practices (Shi et al. 2011). Various [...]

Water intake is recommended for weight loss, but the relationship between water intake and energy metabolism is not clear. We hypothesized that long-term water insufficiency would influence energy, glucose, and lipid metabolism while modulating gut microbiota. Female rats were provided with high-fat diets with different amounts of water and food intake for 6 weeks as follows: water provided for 1 h per day with food ad libitum (WRFA), water supply ad libitum plus pair feeding of with water restricted rats(WAFR), water restriction with ad libitum food for 3 weeks and water and food intake ad libitum for 3 weeks (WR-WA) and ad libitum supply of water and food (WAFA). Water intake in WRFA was about one-third of WAFR and WAFA, whereas food intake was lowered by 30% in WRFA and WAFR than WAFA. Body fat decreased in WRFA and WAFR, but WAFR decreased fat mass more than WRFA. Energy expenditure was lower in WRFA than WAFA and carbohydrate utilization was much higher in WRFA than the other groups. The peak serum glucose concentrations were lower in WAFA than the other groups and WRFA lowered serum insulin levels more than WAFA during OGTT. WRFA shrank the glomerulus with increased apoptotic cells and damaged renal tubules compared to the WAFA and WAFR. WR-WA also exhibited greater glomerular shrinkage and apoptosis that WAFA, but not as much WRFA, indicating that the kidneys were healing after water restriction damage. WRFA exacerbated dyslipidemia compared to the WAFA and WAFR groups. The gut microbiome was similarly modulated in WRFA and WAFR, compared to WAFA, but it was mainly affected by food intake, not water restriction in the host. WRFA and WAFR increased Bacteroidetes and decreased Firmicutes compared WAFA. In conclusion, chronic insufficient water intake induced renal damage, decreased energy expenditure, and exacerbated dyslipidemia in rats with reduced food intake. However, the reduction of food intake improved gut microbiome regardless of insufficient water intake and only minor effects on the microbiome were observed due to water restriction. Keywords: Water deprivation, Insulin, Glucose, Energy expenditure, Gut microbiota, Author(s): James W. Daily[sup.1], Ting Zhang[sup.2], Xuangao Wu[sup.2] and Sunmin Park[sup.2] Introduction The human body is largely composed of water, with intracellular and extracellular water, making up 50-60% of body [...]

Satiation is the process by which eating and drinking reduce appetite. For thirst, oropharyngeal cues have a critical role in driving satiation by reporting to the brain the volume of fluid that has been ingested.sup.1-12. By contrast, the mechanisms that relay the osmolarity of ingested fluids remain poorly understood. Here we show that the water and salt content of the gastrointestinal tract are precisely measured and then rapidly communicated to the brain to control drinking behaviour in mice. We demonstrate that this osmosensory signal is necessary and sufficient for satiation during normal drinking, involves the vagus nerve and is transmitted to key forebrain neurons that control thirst and vasopressin secretion. Using microendoscopic imaging, we show that individual neurons compute homeostatic need by integrating this gastrointestinal osmosensory information with oropharyngeal and blood-borne signals. These findings reveal how the fluid homeostasis system monitors the osmolarity of ingested fluids to dynamically control drinking behaviour. Drinking behaviour in mice is regulated by a signal derived from the water and salt content of the gastrointestinal tract that is transmitted to forebrain neurons that control thirst via the vagus nerve., Author(s): Christopher A. Zimmerman [sup.1] [sup.2] [sup.3] , Erica L. Huey [sup.1] [sup.2] [sup.7] , Jamie S. Ahn [sup.1] [sup.2] [sup.8] , Lisa R. Beutler [sup.2] [sup.4] , Chan Lek [...]

For terrestrial animals and plants, a fundamental cost of living is water vapor lost to the atmosphere during exchange of metabolic gases. Here, by bringing together previously developed models for specific taxa, we integrate properties common to all terrestrial gas exchangers into a universal model of water loss. The model predicts that water loss scales to gas exchange with an exponent of I and that the amount of water lost per unit of gas exchanged depends on several factors: the surface temperature of the respiratory system near the outside of the organism, the gas consumed (oxygen or carbon dioxide), the steepness of the gradients for gas and vapor, and the transport mode (convective or diffusive). Model predictions were largely confirmed by data on 202 species in five taxa--insects, birds, bird eggs, mammals, and plants--spanning nine orders of magnitude in rate of gas exchange. Discrepancies between model predictions and data seemed to arise from biologically interesting violations of model assumptions, which emphasizes how poorly we understand gas exchange in some taxa. The universal model provides a unified conceptual framework for analyzing exchange-associated water losses across taxa with radically different metabolic and exchange systems. carbon dioxide | oxygen | respiration | temperature | scaling doi/ 10.1073/pnas.0905185107

The bacterial spore, the hardiest known life form, can survive in a metabolically dormant state for many years and can withstand high temperatures, radiation, and toxic chemicals. The molecular basis of spore dormancy and resistance is not understood, but the physical state of water in the different spore compartments is thought to play a key role. To characterize this water in situ, we recorded the water [sup.2]H and [sup.17]O spin relaxation rates in [D.sub.2]O-exchanged Bacillus subtilis spores over a wide frequency range. The data indicate high water mobility throughout the spore, comparable with binary protein--water systems at similar hydration levels. Even in the dense core, the average water rotational correlation time is only 50 ps. Spore dormancy therefore cannot be explained by glass-like quenching of molecular diffusion but may be linked to dehydration-induced conformational changes in key enzymes. The data demonstrate that most spore proteins are rotationally immobilized, which may contribute to heat resistance by preventing heat-denatured proteins from aggregating irreversibly. We also find that the water permeability of the inner membrane is at least 2 orders of magnitude lower than for model membranes, consistent with the reported high degree of lipid immobilization in this membrane and with its proposed role in spore resistance to chemicals that damage DNA. The quantitative results reported here on water mobility and transport provide important clues about the mechanism of spore dormancy and resistance, with relevance to food preservation, disease prevention, and astrobiology. Bacillus subtilis | hydration | magnetic relaxation dispersion spore dormancy | spore resistance www.pnas.org/cgi/doi/10.1073/pnas.0908712106

This study investigates the effect of water deprivation on the expression of atrial natirurefic peptide [(ANP).sub.1-28] binding sites in rat kidney. Water deprivation increased the [B.sub.max] of glomerular binding sites for AN[P.sub.1-28] and C-type natriuretic peptide [(CNP).sub.1-22] without modifying their affinity, an effect that was prevented in the presence of C-atrial natriuretic factor (C-ANF), suggesting that natriuretic peptide receptor-C (NPR-C) binding sites might be enhanced. Our results indicate that AN[P.sub.1-28], CN[P.sub.1-22], and C-ANF inhibit cAMP synthesis directly stimulated by forskolin or by the physiological agonists histamine and 5-hydroxytryptamine. The inhibitory effect was found to be significantly greater in water-deprived rats than in controls. Our observations suggest that this effect must be attributed to the 67-kDa NPR-C-like protein, because the 67- and 77-kDa NPR-C-like proteins show high and low affinities for CN[P.sub.1-22], respectively, and the enhanced inhibitory effect of CNP on cAMP generation in water-deprived rats was detected at subnanomolar concentrations. In addition, using affinity cross-linking studies we have observed that water deprivation increases the expression of the 67-kDa NPR-C-like protein, and HS-142, which binds to NPR-A and the 77-kDa NPR-C-like but not the 67-kDa protein, reduced ligand internalization without affecting cAMP inhibition by AN[P.sub.1-28]. Finally, we have found that ligand binding to the 67-kDa NPR-C-like protein is reduced by GTP[gamma]S, suggesting that this receptor is associated with a G protein in renal glomeruli. The enhanced inhibitory role of natriuretic peptides on cAMP synthesis induced by water deprivation may influence glomerular function in the rat kidney. C-type natriuretic peptide; C-atrial natriuretic factor; natriuretic peptide receptur-C

Pseudomonas putida strain mt-2 unsaturated biofilm formation proceeds through three distinct developmental phases, culminating in the formation of a microcolony. The form and severity of reduced water availability alter cell morphology, which influences microcolony size and ultrastructure. The dehydration (matric stress) treatments resulted in biofilms comprised of smaller cells, but they were taller and more porous and had a thicker extracellular polysaccharide layer at the air interface. In the solute stress treatments, cell filamentation occurred more frequently in the presence of high concentrations of ionic (but not nonionic) solutes, and these filamented cells drastically altered the biofilm architecture.

This paper describes a new apparatus and method for measuring swelling dependent electrical conductivity of charged hydrated soft tissues. The apparatus was calibrated using a conductivity standard. Swelling dependent specific conductivity of porcine annulus fibrosis (AF) samples was determined. The conductivity values for porcine AF were similar to those for human and bovine articular cartilage found in the literature. Results revealed a significant linear correlation between specific conductivity and water content for porcine AF tissues tested in phosphate buffered saline (PBS). [DOI: 10.1115/1.1516571]

Octodon degus is a desert rodent of northern Chile, adapted to survive with a limited supply of water. This rodent has a high degree of fecal dehydration, related to colon water absorption. With the hypothesis that aquaporins (AQPs) might be present in the colon epithelium of O. degus and involved in fluid absorption, we studied colon water absorption in vivo and the distribution of AQPs and [Na.sup.+] transporters by immunocytochemistry. AQP-1 was found in apical and basolateral membranes of surface-absorptive and crypt epithelial cells. AQP-8 was found in the cytoplasm of enterocytes of surface colon. AQP-3 immunolabeling, on the other hand, was absent from the epithelium but present in a subepithelial fibroblast layer, pericryptal cells, and muscularis mucosae. The hydration state did not modify the amount of immunostaining for any of the AQPs. Colon water absorption was markedly decreased by the mercurial agent p-chloromercuribenzenesulfonic acid and was not affected by water deprivation. The NHE3 isoform of [Na.sup.+]/[H.sup.+] exchanger and [alpha]-1 subunit of the [Na.sup.+]-[K.sup.+]-ATPase were found in apical and basolateral membranes of surface-absorptive cells, respectively. These results suggest that colon water absorption is mostly transcellular and mediated by water channels like AQP-1. Apical [Na.sup.+]/[H.sup.+] exchanger and basolateral [Na.sup.+]-[K.sup.+]-ATPase in surface cells could be part of the [Na.sup.+] absorption pathway. It is hypothesized that this transport is necessary to provide an osmotic gradient for water absorption. The roles of AQP-8 and AQP-3 in water absorption remain to be established. aquaporin-1; aquaporin-3; aquaporin-8; colon fluid absorption

The mechanisms by which fluid moves across the luminal membrane of cholangiocyte epithelia are uncertain. Previous studies suggested that aquaporin-1 (AQP1) is an important determinant of water movement in rat cholangiocytes and that cyclic AMP mediates the movement of these water channels from cytoplasm to apical membrane, thereby increasing the osmotic water permeability. To test this possibility we measured agonist-stimulated fluid secretion and osmotically driven water transport in isolated bile duct units (IBDUs) from AQP1 wild-type (+/+) and null (-/-) mice. AQP1 expression was confirmed in a mouse cholangiocyte cell line and +/+ liver. Forskolin-induced fluid secretion, measured from the kinetics of IBDU luminal expansion, was 0.05 fl/min and was not impaired in -/- mice. Osmotic water permeability (Pf), measured from the initial rate of IBDU swelling in response to a 70-mosM osmotic gradient, was 11.1 x [10.sup.-4] cm/s in +/+ mice and 11.5 x [10.sup.-4] cm/s in -/- mice. [P.sub.f] values increased by ~50% in both +/+ and -/- mice following preincubation with forskolin. These findings provide direct evidence that AQP1 is not rate limiting for water movement in mouse cholangiocytes and does not appear to be regulated by cyclic AMP in this species. aquaporins; cholangiocytes; bile formation; adenosine 3',5'-cyclic monophosphate

The physiological relevance of the absorption of glucose from bile by cholangiocytes remains unclear. The aim of this study was to test the hypothesis that absorbed glucose drives aquaporin (AQP)-mediated water transport by biliary epithelia and is thus involved in ductal bile formation. Glucose absorption and water transport by biliary epithelia were studied in vitro by microperfusing intrahepatic bile duct units (IBDUs) isolated from rat liver. In a separate set of in vivo experiments, bile flow and absorption of biliary glucose were measured after intraportal infusion of D-glucose or phlorizin. IBDUs absorbed D-glucose in a dose- and phlorizin-dependent manner with an absorption maximum of 92.8 [+ or -] 6.2 pmol*[min.sup.-1]*[mm.sup.-1]. Absorption of D-glucose by microperfused IBDUs resulted in an increase of water absorption ([J.sub.v] = 3-10 nl*[min.sup.-1]*[mm.sup.-1], [P.sub.f] = 40 x [10.sup.-3] cm/sec). Glucose-driven water absorption by IBDUs was inhibited by Hg[Cl.sub.2], suggesting that water passively follows absorbed D-glucose mainly transcellularly via mercury-sensitive AQPs. In vivo studies showed that as the amount of absorbed biliary glucose increased after intraportal infusion of D-glucose, bile flow decreased. In contrast, as the absorption of biliary glucose decreased after phlorizin, bile flow increased. Results support the hypothesis that the physiological significance of the absorption of biliary glucose by cholangiocytes is likely related to regulation of ductal bile formation. liver; cholangiocytes; absorption; secretion; aquaporins; phlorizin; microperfusion; intrahepatic bile duct units

The author reviews the publications on organic synthesis in water. The topics of interest include the advances in performing diastereo- and enantioselective reactions in aqueous media and the means of solubilizing organic compounds and catalysis in water.

The author reviews publications on glass transition and liquid fragility. The topics of interest include glass transition in aqueous solutions and in water and fragility of aqueous solutions and water.

The authors review the publications on liquid water structure. The topics of interest include the simulation of this liquid water structure and its thermodynamic and phase stability properties.

Research has been conducted on the thionocarbonate compounds. The reactions of these compounds with the secondary alicyclic amines have been carried out in water and ethanol and the kinetic investigation of these reactions is presented.

Research has been conducted on the spheroidal molecular assemblies in polar organic media. The access to these assemblies has been developed and the results indicate that the assemblies are composed of building blocks based on ammonium cations and phosphonate anions.

Research has been conducted on the triangle-square equilibrium. The dependence of this equilibrium on water and anions and the crystallization method of the species have been investigated and are reported.

Research has been conducted on the tetraazamacrocyclic ligands. The design of these ligands constructed with the aim to sensitize luminescence of terbium(III) and europium(III) ions in water is described.

Research has been conducted on the water-catalyzed dithiocarbamic acid cleavage. The study of this cleavage carried out via the use of N-methyl- and N-phenyldithiocarbamic acids is presented.