Iso-osmotic Conditions Research Articles

Effects of amount of lactose in milk replacer on gastrointestinal function of dairy calves

The objective of this study was to evaluate the effects of feeding milk replacer (MR) at different lactose amount while keeping osmolality constant on gastrointestinal function, blood parameters, and inflammation-related mRNA expression in the livers of dairy calves. Fifteen Holstein bull calves were assigned to one of three dietary treatments differing in MR lactose content (L: 38 %, M: 41 %, and H: 46 %). Feeding of the test diets was started at 1 day of age and gradually increased to a maximum feeding rate at 20 days of age (L: 1.16 kg/d, M: 1.21 kg/d, and H: 1.26 kg/d DM). Under these conditions, the lactose dosages for the treatments were 441 g/d, 496 g/d, and 580 g/d, respectively. The MR were prepared to ensure isocaloric and iso-osmotic (451 mOsm/kg) conditions. Fecal scores were recorded daily, and at 14 and 28 days of age, blood and breath samples were collected before and after MR feeding. In addition, feces and urine were collected for 2 consecutive days. Then, the calves were slaughtered to evaluate intestinal permeability and liver mRNA expression. The permeability in the duodenum and ileum was lower in H and M than in L; the permeability in the jejunum was also lower in H than in L. The hepatic mRNA expressions of toll-like receptor-2, IL-1β, and tumor-necrosis factor-α were lower in H and M than L. Nitrogen retention was higher in H than in L, and linear and quadratic increasing trends were observed in tissue ratio of gastrointestinal tract with the increase in lactose amount. Postprandial increase in plasma glucose concentration was smaller and postprandial increase in TG concentration was higher in H than in L. Fecal properties, digestibility, and breath hydrogen concentrations were not affected by treatment. These results indicate that feeding high-lactose MR may increase gastrointestinal weight and decrease permeability in the small intestine of calves.

Hypo-osmolality activates Wnt/β-catenin mediated by AQP1 in nucleus pulposus cells degeneration.

The goals of this study were to investigate whether Wnt/β-catenin signaling plays a role in hypo-osmolality-related degeneration of nucleus pulposus (NP) cells, and if so, to define the mechanism underlying AQP1 in this effect. Human NP cells were cultured under hypo-osmotic (300/350/400 mOsm) and iso-osmotic (450 mOsm) conditions. The cell viability, AQP1, the expression of Wnt/β-catenin signaling, collagen II/I, and MMP3/9 were evaluated. To determine the effects of the Wnt/β-catenin signaling, we used the inhibitor and the activator of Wnt during the hypo-osmotic culture of NP cells. We also examined whether the silencing and overexpressing of the AQP1 gene would affect the Wnt/β-catenin expression in NP cells. Hypo-osmolality caused NP cell degeneration and activated the Wnt/β-catenin signaling but suppressed the AQP1 level. Inhibiting the Wnt/β-catenin signaling alleviated the hypo-osmolality-induced NP cell degeneration. On the contrary, activating Wnt/β-catenin aggravated the NP cell degeneration under hypo-osmotic conditions, which did not affect AQP1 expression. AQP1-overexpressed NP cells exhibited decreased Wnt/β-catenin signaling and alleviated cell degeneration under the hypo-osmotic condition. Besides, AQP1 silencing accelerated NP cell degeneration and activated Wnt/β-catenin expression compared with untreated control. Hypo-osmolality promotes NP cell degeneration via activating Wnt/β-catenin signaling, which is suppressed by AQP1 expression. The upregulation of AQP1 suppressed the Wnt/β-catenin signaling and alleviated the hypo-osmolality induced by the NP cell degeneration.

Understanding Bidirectional Water Transport across Bronchial Epithelial Cell Monolayers: A Microfluidic Approach.

Deciphering the dynamics of water transport across bronchial epithelial cell monolayers is pivotal for unraveling respiratory physiology and pathology. In this study, we employ an advanced microfluidic system to explore bidirectional water transport across 16HBE14σ bronchial epithelial cells. Previous experiments unveiled electroneutral multiple ion transport, with chloride ions utilizing transcellular pathways and sodium ions navigating both paracellular and transcellular routes. Unexpectedly, under isoosmotic conditions, rapid bidirectional movement of Na+ and Cl- was observed, leading to the hypothesis of a substantial transport of isoosmotic solution (145 mM NaCl) across cell monolayers. To validate this conjecture, we introduce an innovative microfluidic device, offering a 500-fold sensitivity improvement in quantifying fluid flow. This system enables the direct measurement of minuscule fluid volumes traversing cell monolayers with unprecedented precision. Our results challenge conventional models, indicating a self-regulating mechanism governing water transport that involves the CFTR channel and anion exchangers. In healthy subjects, equilibrium is achieved at an apical potential of Δφap = -30 mV, while subjects with cystic fibrosis exhibit modulation by an anion exchanger, reaching equilibrium at [Cl] = 67 mM in the airway surface liquid. This nuanced electrochemical basis for bidirectional water transport in bronchial epithelia sheds light on physiological intricacies and introduces a novel perspective for understanding respiratory conditions.

Iso-osmotic calcium nitrate and sodium chloride stresses have differential effects on growth and photosynthetic capacity in tomato

Calcium nitrate [Ca(NO3)2] and sodium chloride (NaCl) are among the main salts used in cultivation and present in salinized soil, respectively. These salts at high levels would reduce photosynthetic capacity and eventually cause a reduction in tomato growth. To better understand the growth disruption caused by Ca(NO3)2 salt (from the fertilizer) and the other predominant salt NaCl in salinized soils, tomato plants were grown in half-strength Hoagland's nutrient solution with three treatments. Through 7 days of salt stress and later 7 days of recovery, we investigated tomato seedling growth, nonstructural carbohydrates accumulation, antioxidant capacity, photosynthetic gas exchange, and chlorophyll fluorescence parameters. We found that Ca(NO3)2 and NaCl stresses increased the levels of nonstructural carbohydrates, reactive oxygen species (ROS), and various antioxidant enzyme activities in tomatoes while lowering foliar photosynthetic capacity. Under iso-osmotic salt stress conditions, the disruption of photosynthesis by NaCl was greater than that brought about by the Ca(NO3)2 treatment, which was attributed to Na+ accumulation. Interestingly, Na+ increased the levels of nonstructural carbohydrates and disrupted the feedback inhibition of photosynthesis. In addition, Na+ inhibited the activities of antioxidant enzymes, leading to more ROS production that would disrupt the processes within various photosynthetic apparatus. Our study further revealed that foliar nonstructural carbohydrates played an important role in delaying the onset of photoinhibition and rapid recovery of photosystem damage after Na+stress.

Mechanistic Effects of Baicalein on Aqueous Humor Drainage and Intraocular Pressure.

Elevated intraocular pressure (IOP) is a major risk factor for glaucoma that results from impeded fluid drainage. The increase in outflow resistance is caused by trabecular meshwork (TM) cell dysfunction and excessive extracellular matrix (ECM) deposition. Baicalein (Ba) is a natural flavonoid and has been shown to regulate cell contraction, fluid secretion, and ECM remodeling in various cell types, suggesting the potential significance of regulating outflow resistance and IOP. We demonstrated that Ba significantly lowered the IOP by about 5 mmHg in living mice. Consistent with that, Ba increased the outflow facility by up to 90% in enucleated mouse eyes. The effects of Ba on cell volume regulation and contractility were examined in primary human TM (hTM) cells. We found that Ba (1–100 µM) had no effect on cell volume under iso-osmotic conditions but inhibited the regulatory volume decrease (RVD) by up to 70% under hypotonic challenge. In addition, Ba relaxed hTM cells via reduced myosin light chain (MLC) phosphorylation. Using iTRAQ-based quantitative proteomics, 47 proteins were significantly regulated in hTM cells after a 3-h Ba treatment. Ba significantly increased the expression of cathepsin B by 1.51-fold and downregulated the expression of D-dopachrome decarboxylase and pre-B-cell leukemia transcription factor-interacting protein 1 with a fold-change of 0.58 and 0.40, respectively. We suggest that a Ba-mediated increase in outflow facility is triggered by cell relaxation via MLC phosphorylation along with inhibiting RVD in hTM cells. The Ba-mediated changes in protein expression support the notion of altered ECM homeostasis, potentially contributing to a reduction of outflow resistance and thereby IOP.

Pericellular heparan sulfate proteoglycans: Role in regulating the biosynthetic response of nucleus pulposus cells to osmotic loading.

BackgroundDaily physiologic loading causes fluctuations in hydration of the intervertebral disc (IVD); thus, the embedded cells experience cyclic alterations to their osmotic environment. These osmotic fluctuations have been described as a mechanism linking mechanics and biology, and have previously been shown to promote biosynthesis in chondrocytes. However, this phenomenon has yet to be fully interrogated in the IVD. Additionally, the specialized extracellular matrix surrounding the cells, the pericellular matrix (PCM), transduces the biophysical signals that cells ultimately experience. While it is known that the PCM is altered in disc degeneration, whether it disrupts normal osmotic mechanotransduction has yet to be determined. Thus, our objectives were to assess: (1) whether dynamic osmotic conditions stimulate biosynthesis in nucleus pulposus cells, and (2) whether pericellular heparan sulfate proteoglycans (HSPGs) modulate the biosynthetic response to osmotic loading.MethodsBovine nucleus pulposus cells isolated with retained PCM were encapsulated in 1.5% alginate beads and treated with or without heparinase III, an enzyme that degrades the pericellular HSPGs. Beads were subjected to 1 h of daily iso‐osmotic, hyper‐osmotic, or hypo‐osmotic loading for 1, 2, or 4 weeks. At each timepoint the total amount of extracellular and pericellular sGAG/DNA were quantified. Additionally, whether osmotic loading triggered alterations to HSPG sulfation was assessed via immunohistochemistry for the heparan sulfate 6‐O‐sulfertransferase 1 (HS6ST1) enzyme.ResultsOsmotic loading significantly influenced sGAG/DNA accumulation with a hyper‐osmotic change promoting the greatest sGAG/DNA accumulation in the pericellular region compared with iso‐osmotic conditions. Heparanase‐III treatment significantly reduced extracellular sGAG/DNA but pericellular sGAG was not affected. HS6ST1 expression was not affected by osmotic loading.ConclusionResults suggest that hyper‐osmotic loading promotes matrix synthesis and that modifications to HSPGs directly influence the metabolic responses of cells to osmotic fluctuations. Collectively, results suggest degeneration‐associated modifications to pericellular HSPGs may contribute to the altered mechanobiology observed in disease.

Early and abrupt salinity reduction impacts European eel larval culture.

Reducing water salinity towards iso-osmotic conditions is a common practice applied in euryhaline fish farming to limit osmoregulation costs and enhance growth. In this respect, the present study investigated the timing of salinity reduction in an abrupt manner during European eel (Anguilla anguilla) larval culture by examining associated impacts on morphological and molecular levels. Larvae from 3 different parental combinations (families) were reared at constant 36 psu for 6days (control) or subjected to a direct reduction to 18 psu on 1, 2, or 3days post-hatch. Overall, salinity reduction enhanced growth and survival, resulting from more efficient energy resource utilization. In the control group, expression of growth-related igf2 remained constant, demonstrating a steady growth progression, while igf1 expression increased over time only for the salinity reduced treatments, potentially qualifying as a useful biomarker for growth performance. Even though each parental combination seems to have a different capacity to cope with salinity alterations, as observed by family-driven water-transport-related aquaporin (aqp1, aqp3) gene expression, it could be inferred that the abrupt salinity change is generally not stressful, based on non-upregulated heat shock proteins (hsp70, hsp90). However, the applied salinity reduction (irrespective of timing) induced the development of pericardial edema. As such, we conclude that despite the positive effect of salinity reduction on early growth and survival, the long-term benefit for eel larval culture lies in establishing a protocol for salinity reduction, at a precise developmental time point, without causing pericardial malformations.

Performance thresholds of hatchery produced European eel larvae reared at different salinity regimes

The future of European eel aquaculture depends on closing the life cycle in captivity. Present focus is on developing suitable larval rearing technology. This study explored new salinity reduction applications to elucidate performance thresholds of European eel larvae produced under realistic hatchery conditions, using Kreisel tanks and recirculating aquaculture systems for larval culture. The study links eel larval survival and biometrics to expression of genes related to underlying molecular mechanisms by taking parental effects into account. Larvae from different families were reared either at constant salinity of 36 psu (Control) or subjected to salinity reduction (36 to 18 psu) initiated 3 days post hatch (dph) and at a rate of 4 psu/day, occurring either within 1 h (Fast) or 24 h (Slow). An extreme scenario, reducing salinity directly from 36 to 18 psu within 1 h on 6 dph (Drastic) was also tested. Early and gradual salinity reduction (Slow or Fast) led to increased growth rate and larger larvae, while influencing the expression of dio3 (deiodination mechanism and thyroid endocrine system). Expression of atp6 and cox1 (energy metabolism) was constant, indicating that energy metabolism was stable and independent of salinity, while expression of nkcc1a (ion regulation) was upregulated in the Control, suggesting an upregulation of active Na+, K+, and Cl− transport and thus increased cellular energy consumption. This explained that eel larvae experiencing an early and progressive salinity reduction, used their energy reserves more efficiently, leading to improved growth and survival. However, salinity reduction caused heart edema. Expression patterns of 12 genes [stress/repair (hsp90), immune response (mhc2), neurogenesis (neurod4), deiodination (dio2), thyroid metabolism (thαa, thαb, thβb), energy metabolism (atp6), skeletogenesis (bmp2b, bmp5), growth (igf2b), ion regulation (nkcc2b)] on 6 dph and 5 genes [water transport (aqp3), immune response (il1β), thyroid metabolism (thβb), skeletogenesis (bmp5), heart development (nppb)] on 12 dph were driven by genotype (family) × environment (salinity) interactions, revealing batch specific phenotypic plasticity and describing a genetic programming of molecular mechanisms and intrinsic sensitivity to environmental drivers that need to be considered in future eel aquaculture. In conclusion, early and progressive salinity reduction (Fast or Slow) benefits larval eel growth and survival, but emerging implications regarding heart edema need to be addressed in future studies. On the other hand, we show that biotechnical difficulties for introducing salinity reductions, can be circumvented by directly moving larvae from seawater to isoosmotic conditions, but suited application timing needs to be explored.

Analysis of changes in sodium and chloride ion transport in the skin

The measurement of electric potential and resistance reflect the transport of sodium and chloride ions which take place in keratinocytes and is associated with skin response to stimuli arising from external and internal environment. The aim of the study was to assess changes in electrical resistance and the transport of chloride and sodium ions, under iso-osmotic conditions and following the use of inhibitors affecting these ions’ transport, namely amiloride (A) and bumetanide (B). The experiment was performed on 104 fragments of rabbit skin, divided into three groups: control (n = 35), A—inhibited sodium transport (n = 33) and B—inhibited chloride transport (n = 36). Measurement of electrical resistance (R) and electrical potential (PD) confirmed tissue viability during the experiment, no statistically significant differences in relation to control conditions were noted. The minimal and maximal PD measured during stimulation confirmed the repeatability of the recorded reactions to the mechanical and mechanical–chemical stimulus for all examined groups. Measurement of PD during stimulation showed differences in the transport of sodium and chloride ions in each of the analyzed groups relative to the control. The statistical analysis of the PD measured in stationary conditions and during mechanical and/or mechanical–chemical stimulation proved that changes in sodium and chloride ion transport constitute the physiological response of keratinocytes to changes in environmental conditions for all applied experimental conditions. Assessment of transdermal ion transport changes may be a useful tool for assessing the skin condition with tendency to pain hyperactivity and hypersensitivity to xenobiotics.

Germination responses of Lycium humile, an extreme halophytic Solanaceae: understanding its distribution in saline mudflats of the southern Puna

Although knowledge about halophytic Solanaceae is scarce, it is known that several species within genus Lycium tolerate salinity. Lycium humile grows in highly saline soils in mudflats near saline Andean lakes. This study evaluated the germination responses of L. humile under different scarification methods, photoperiods, temperatures and saline conditions and, simultaneously, tested seedling survival under different iso-osmotic conditions. Dormancy and germination were found to be regulated by interactions with different factors, with the highest germination percentages being obtained by immersion in sulfuric acid, with a temperature of 25 °C and a temperature regime of 5/25 °C, under which seeds were neutrally photoblastic. As osmotic potential of saline solutions decreased, germination also decreased drastically but the seedling survival percentage was higher than 30 % at 600 mM NaCl. No seeds germinated in any of the polyethylene glycol (PEG) solutions and no seedling survival was observed from -1.2 MPa PEG solutions. More than 90 % of seeds incubated in NaCl were able to recover germination after being transferred to distilled water, independently of NaCl treatments. We concluded that the effects of extreme environmental conditions on germination responses and seed tolerance to salinity may determine the occurrence and restricted distribution of L. humile.

Mechanical Shielding in Plant Nuclei.

In animal single cells in culture, nuclear geometry and stiffness can be affected by mechanical cues, with important consequences for chromatin status and gene expression. This calls for additional investigation into the corresponding physiological relevance in a multicellular context and in different mechanical environments. Using the Arabidopsis root as a model system, and combining morphometry and micro-rheometry, we found that hyperosmotic stress decreases nuclear circularity and size and increases nuclear stiffness in meristematic cells. These changes were accompanied by enhanced expression of touch response genes. The nuclear response to hyperosmotic stress was rescued upon return to iso-osmotic conditions and could even lead to opposite trends upon hypo-osmotic stress. Interestingly, nuclei in a mutant impaired in the functions of the gamma-tubulin complex protein 3 (GCP3) interacting protein (GIP)/MZT1 proteins at the nuclear envelope were almost insensitive to such osmotic changes. The gip1gip2 mutant exhibited constitutive hyperosmotic stress response with stiffer and deformed nuclei, as well as touch response gene induction. The mutant was also resistant to lethal hyperosmoticconditions. Altogether, we unravel a stereotypical geometric, mechanical, and genetic nuclear response to hyperosmotic stress in plants. Our data also suggest that chromatin acts as a gel that stiffens in hyperosmotic conditions and that the nuclear-envelope-associated protein GIPs act as negative regulators of this response.

Indirect Role of AQP4b and AQP4d Isoforms in Dynamics of Astrocyte Volume and Orthogonal Arrays of Particles.

Water channel aquaporin 4 (AQP4) plays a key role in the regulation of water homeostasis in the central nervous system (CNS). It is predominantly expressed in astrocytes lining blood–brain and blood–liquor boundaries. AQP4a (M1), AQP4c (M23), and AQP4e, present in the plasma membrane, participate in the cell volume regulation of astrocytes. The function of their splicing variants, AQP4b and AQP4d, predicted to be present in the cytoplasm, is unknown. We examined the cellular distribution of AQP4b and AQP4d in primary rat astrocytes and their role in cell volume regulation. The AQP4b and AQP4d isoforms exhibited extensive cytoplasmic localization in early and late endosomes/lysosomes and in the Golgi apparatus. Neither isoform localized to orthogonal arrays of particles (OAPs) in the plasma membrane. The overexpression of AQP4b and AQP4d isoforms in isoosmotic conditions reduced the density of OAPs; in hypoosmotic conditions, they remained absent from OAPs. In hypoosmotic conditions, the AQP4d isoform was significantly redistributed to early endosomes, which correlated with the increased trafficking of AQP4-laden vesicles. The overexpression of AQP4d facilitated the kinetics of cell swelling, without affecting the regulatory volume decrease. Therefore, although they reside in the cytoplasm, AQP4b and AQP4d isoforms may play an indirect role in astrocyte volume changes.

Silicon Improves Rice Salinity Resistance by Alleviating Ionic Toxicity and Osmotic Constraint in an Organ-Specific Pattern.

Salinity stress severely inhibits the growth of plant via ionic toxicity and osmotic constraint. Exogenous silicon (Si) can alleviate salinity stress, but the mechanisms behind remain unclear. To investigate the role of Si in alleviating ionic and osmotic components of salinity, rice (Oryza sativa L.) seedlings were grown hydroponically in iso-osmotic stress conditions developed from NaCl or polyethylene glycol (PEG). The effects of Si on the growth of shoot and root of rice under salinity and PEG-derived osmotic stress were evaluated and further compared using principal coordinate analysis (PCoA). We also analyzed the concentrations of Na, K, and compatible osmolytes, tissue sap osmotic potential, antioxidant enzymes activities, and the expression of aquaporin genes. Generally, Si significantly promoted shoot and root growth in rice exposed to both NaCl and PEG. PCoA shows that the Si-induced distance change under NaCl treatment was larger than that under PEG treatment in the shoot, while the Si-induced distance changes under NaCl and PEG treatments were at an equal level in the root. Under salinity, Si decreased Na concentration and Na/K ratio in the shoot but not in the root. However, Si decreased net Na uptake and increased root Na accumulation content. Osmotic potential was increased in the shoot but decreased in the root by Si addition. Si decreased soluble sugar and proline concentrations in the shoot but increased soluble sugar and soluble protein concentrations in the root. Besides, Si promoted shoot transpiration rate and root morphological traits. Although both NaCl and PEG treatments upregulated aquaporin gene expression, Si addition maintained the expression of OsPIPs under NaCl and PEG treatments at same levels as control treatment. Furthermore, Si alleviated oxidative damages under both NaCl and PEG by regulating antioxidant enzyme activities. In summary, our results show that Si improves salt stress tolerance in rice by alleviating ionic toxicity and osmotic constraint in an organ-specific pattern. Si ameliorates ionic toxicity by decreasing Na uptake and increasing root Na reservation. Si alleviates osmotic constraint by regulating root morphological traits and root osmotic potential but not aquaporin gene expression for water uptake, and promoting transpiration force but not osmotic force in shoot for root-to-shoot water transport.

Metabolic responses of wheat seedlings to osmotic stress induced by various osmolytes under iso-osmotic conditions.

Many environmental stresses cause osmotic stress which induces several metabolic changes in plants. These changes often vary depending on the genotype, type and intensity of stress or the environmental conditions. In the current experiments, metabolic responses of wheat to osmotic stress induced by different kinds of osmolytes were studied under iso-osmotic stress conditions. A single wheat genotypes was treated with PEG-6000, mannitol, sorbitol or NaCl at such concentrations which reduce the osmotic potential of the culture media to the same level (-0.8MPa). The metabolic changes, including the accumulation of proline, glycine betaine (GB) and sugar metabolites (glucose, fructose, galactose, maltose and sucrose) were studied both in the leaves and roots together with monitoring the plant growth, changes in the photosynthetic activity and chlorophyll content of the leaves. In addition, the polyamine metabolism was also investigated. Although all osmolytes inhibited growth similarly, they induced different physiological and metabolic responses: the CO2 assimilation capacity, RWC content and the osmotic potential (ψπ) of the leaves decreased intensively, especially after mannitol and sorbitol treatments, followed by NaCl treatment, while PEG caused only a slight modification in these parameters. In the roots, the most pronounced decrease of ψπ was found after salt-treatments, followed by PEG treatment. Osmotic stress induced the accumulation of proline, glycine betaine and soluble sugars, such as fructose, glucose, sucrose and galactose in both the root and leaf sap. Specific metabolic response of roots and leaves under PEG included accumulation of glucose, fructose and GB (in the roots); sucrose, galactose and proline synthesis were dominant under NaCl stress while exposure to mannitol and sorbitol triggered polyamine metabolism and overproduction of maltose. The amount of those metabolites was time-dependent in the manner that longer exposure to iso-osmotic stress conditions stimulated the sugar metabolic routes. Our results showed that the various osmolytes activated different metabolic processes even under iso-osmotic stress conditions and these changes also differed in the leaves and roots.

Crystallizable W/O/W double emulsions made with milk fat: Formulation, stability and release properties

Food grade Water-in-oil-in-water W/O/W double emulsions with high encapsulation efficiency, controlled texture and triggered leakage are usually sought after in many food applications (e.g. functional foods) and still the subject of active research interest. For that purpose, we have used an edible crystallizable oil which is Anhydrous Milkfat (AMF) with high encapsulation properties, as recently demonstrated. The emulsions encapsulating a nutrient (MgCl2) were formulated using two surface-active species (polyglycerol polyricinoleate and sodium caseinate being also a chelating agent able to bind magnesium ions). The internal droplet and oil globule diameters were identical for all the systems. The stability of the double emulsions and the rate of magnesium release from the internal to the external aqueous phase were monitored during 24 days of storage at 4 °C, as a function of the formulation and globule volume fraction. It was found that in all cases, magnesium leakage occurred without film rupturing (no coalescence) and the double structure was preserved with time. On the other hand and at iso-osmotic conditions, the rate of Mg release was low (does not exceed 14% after 24 days of storage at 4 °C), independent on the concentration of sodium caseinate in the external aqueous phase, remained time independent and its level of release was lowered by increasing the globule volume fraction. Under moderate hypo osmotic conditions (∆P = +1.159 atm until +3.343 atm), the Mg release increased with the osmotic pressure gradient but remained also time independent. However, at large osmotic gradient (∆P = +5.503 atm), the Mg2+ release was triggered fastly and increased with time, in agreement with a no more protective structure, being beneficial for several food applications. The experimental data were interpreted and the permeation coefficient of Mg was determined within the frame of a mean-field model based on diffusion/permeation, integrating the transport in opposite direction than Mg2+, of the osmotic regulator, even occurring at different rates through the oil phase. Under hyper osmotic conditions (even large, ∆P = −7.502 atm), the Mg release was low, time independent and the double structure was usually preserved over time. So, this study allows to improve magnesium retention and its controlled release, in particular for nutritional and food applications.

Effects of sodium ions on rat thyrocyte (FRTL-5 cells) swelling- and thyrotropin-activated taurine efflux dependent on cAMP and Epac.

Cellular osmolyte release is important in preventing water accumulation and swelling. However, the signaling pathways that detect volume increase and activate solute efflux are still not fully understood. We investigated efflux activation of the osmolyte taurine which is actively accumulated in rat thyrocytes (FRTL-5). Efflux of accumulated [(3)H]taurine was stimulated by cellular swelling and thyrotropin (TSH). These effects were significantly diminished in cells having reduced TSH receptor concentrations. Phosphodiesterase inhibitors (IBMX, Rolipram) enhanced both responses. An analog of forskolin (FSK; 7-deacetyl-7-[O-(N-methylpiperazino)-γ-butyryl] dihydrochloride) and an analog of cAMP, specific for activating exchange protein activated directly by cAMP (Epac; 8-(4-chlorophenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate, acetoxymethyl ester), significantly stimulated [(3)H]taurine efflux. A cAMP analog specific for activating protein kinase A (PKA; N6-benzoyladenosine-3',5'-cyclic monophosphate, acetoxymethyl ester) had no significant stimulatory effect on [(3)H]taurine efflux rate. The amiloride analog, 5-(N-ethyl-N-isopropyl)-amiloride, which inhibits a TSH-stimulated Na(+)/H(+) exchanger, enhanced (100 %) and ouabain inhibited (50 %) the TSH-stimulated [(3)H]taurine efflux rate. The effect of FSK on efflux was strongly potentiated by Na(+)-free iso-osmotic conditions and by osmolality/cell volume that affected also the db-cAMP-stimulated efflux. The TSH receptors and downstream elements of the signaling pathway comprising adenylyl cyclase, cAMP and Epac appeared to mediate the hormone-induced signal for [(3)H]taurine efflux from FRTL-5 cells. With less evidence, the cell volume/osmolality-induced [(3)H]taurine efflux cascade appeared to share some of the hormone signaling elements and to modulate the hormone signaling pathway at two levels through cellular Na(+).

Growth performance of pearl goldfish juvenile carassius auratus cultured in 3 ppt salinity with different exposure time of electric field

<p>ABSTRACT</p><p><br />Growth rate of pearl goldfish juvenile Carassius auratus relatively slow to reach market size which will take approximately three months. To accelerate its growth can be done by providing exposure of the fish to low-power electric fields (10 V) via 3 ppt salinity water, with the goal of providing the close isoosmotic conditions, and also to streamline the flow of electricity from the electrodes to the body of the fish. This study aims to calculate the survival and growth rate of pearl goldfish juvenile of S sizes (2‒4 cm of body length) which were maintained at 3 ppt salinity water and treated by different exposure time of electric field (zero, two, four, and six minutes before feeding) with 10 volt electric power. Fish were cultured at a density of 2 fish/L in the (20×30×20 cm3) aquaria in volume of 6 L of water. Test fish had an average body length of 4.11±0.05 cm and the average body weight of 2.89±0.05 g. Exposure time of electric field were zero, two, four, and six minutes before the fish are fed, performed every day as much as three times i.e. morning, afternoon, and evening. The research design used was completely randomized design with four treatments, namely 0, 2, 4, and 6 (time for exposure is zero/control, two, four, and six minute) with three replications. The results show test fishes exposed to 10 volt electrical field for zero, two, four, and six minutes, have no significant effect on survival rate (P>0.05). For growth performance, four minute exposure treatment gives the best results compared to controls (P<0.05), supported by an increase in the percentage of the ratio of gut length to body length of the fish and higher feed efficiency.<br />Keywords: long exposure to the electric field, growth performance, pearl goldfish</p><p><br />ABSTRAK</p><p><br />Pertumbuhan benih ikan hias maskoki mutiara Carassius auratus relatif lambat, karena untuk mencapai ukuran jual memerlukan waktu sekitar tiga bulan. Untuk mempercepat pertumbuhannya dapat dilakukan dengan pemberian paparan medan listrik berdaya rendah (10 V) ke air media budidaya yang dinaikkan salinitasnya menjadi 3 ppt, dengan tujuan memberikan kondisi mendekati isoosmotik, dan juga untuk mengefektifkan arus listrik dari elektroda ke tubuh ikan. Penelitian ini bertujuan untuk menghitung tingkat kelangsungan hidup dan pertumbuhan benih ikan maskoki mutiara ukuran S (2‒4 cm) yang dipelihara pada media bersalinitas 3 ppt yang diberi perlakuan lama waktu pemaparan medan listrik (nol, dua, empat, dan enam menit sebelum ikan diberi pakan) dengan daya 10 volt. Ikan dipelihara dengan kepadatan 2 ekor/L dalam akuarium berukuran 20×30×20 cm3 dengan volume air 6 L. Ikan uji yang digunakan memiliki panjang rata-rata 4,11±0,05 cm dan bobot rata-rata 2,89±0,05 g/ekor. Pemberian paparan medan listrik dilakukan selama nol, dua, empat, dan enam menit sebelum ikan diberi pakan, dilakukan setiap hari sebanyak tiga kali yaitu pagi, siang, dan sore hari. Rancangan penelitian terdiri atas empat perlakuan, yaitu 0, 2, 4, dan 6 (lama paparan nol/kontrol, dua, empat, dan enam menit) yang diulang masing-masing tiga kali ulangan. Hasil pemaparan arus listrik 10 volt selama nol, dua, empat, dan enam menit, tidak memberikan pengaruh yang nyata pada kelangsungan hidup (p>0,05). Untuk kinerja pertumbuhan, perlakuan paparan empat menit memberikan hasil yang terbaik dibandingkan kontrol (p<0,05), didukung oleh peningkatan persentase nilai rasio panjang usus terhadap panjang tubuh ikan serta nilai efisiensi pakan yang lebih tinggi.</p><p><br />Kata kunci: lama paparan medan listrik, kinerja pertumbuhan, ikan maskoki mutiara</p>

Ibuprofen-in-cyclodextrin-in-W/O/W emulsion – Improving the initial and long-term encapsulation efficiency of a model active ingredient

A challenge in formulating water-in-oil-in-water (W/O/W) emulsions is the uncontrolled release of the encapsulated compound prior to application. Pharmaceuticals and nutraceuticals usually have amphipathic nature, which may contribute to leakage of the active ingredient. In the present study, cyclodextrins (CyDs) were used to impart a change in the relative polarity and size of a model compound (ibuprofen) by the formation of inclusion complexes. Various inclusion complexes (2-hydroxypropyl (HP)-β-CyD-, α-CyD- and γ-CyD-ibuprofen) were prepared and presented within W/O/W emulsions, and the initial and long-term encapsulation efficiency was investigated. HP-β-CyD-ibuprofen provided the highest encapsulation of ibuprofen in comparison to a W/O/W emulsion with unassociated ibuprofen confined within the inner water phase, with a four-fold increase in the encapsulation efficiency. An improved, although lower, encapsulation efficiency was obtained for the inclusion complex γ-CyD-ibuprofen in comparison to HP-β-CyD-ibuprofen, whereas α-CyD-ibuprofen had a similar encapsulation efficiency to that of unassociated ibuprofen. The lower encapsulation efficiency of ibuprofen in combination with α-CyD and γ-CyD was attributed to a lower association constant for the γ-CyD-ibuprofen inclusion complex and the ability of α-CyD to form inclusion complexes with fatty acids. For the W/O/W emulsion prepared with HP-β-CyD-ibuprofen, the highest encapsulation of ibuprofen was obtained at hyper- and iso-osmotic conditions and by using an excess molar ratio of CyD to ibuprofen. In the last part of the study, it was suggested that the chemical modification of the HP-β-CyD molecule did not influence the encapsulation of ibuprofen, as a similar encapsulation efficiency was obtained for an inclusion complex prepared with mono-1-glucose-β-CyD.

Retraction note: Gene expression analysis in response to osmotic stimuli in the intervertebral disc with DNA microarray.

Intervertebral disc (IVD) cells experience a broad range of physicochemical stimuli under physiologic conditions, including alterations in their osmotic environment. At present, the molecular mechanisms underlying osmotic regulation in IVD cells are poorly understood. This study aims to screen genes affected by changes in osmotic pressure in cells of subjects aged 29 to 63 years old, with top-scoring pair (TSP) method. Gene expression data set GSE1648 was downloaded from Gene Expression Omnibus database, including four hyper-osmotic stimuli samples, four iso-osmotic stimuli samples, and three hypo-osmotic stimuli samples. A novel, simple method, referred to as the TSP, was used in this study. Through this method, there was no need to perform data normalization and transformation before data analysis. A total of five pairs of genes ((CYP2A6, FNTB), (PRPF8, TARDBP), (RPS5, OAZ1), (SLC25A3, NPM1) and (CBX3, SRSF9)) were selected based on the TSP method. We inferred that all these genes might play important roles in response to osmotic stimuli and age in IVD cells. Additionally, hyper-osmotic and iso-osmotic stimuli conditions were adverse factors for IVD cells. We anticipate that our results will provide new thoughts and methods for the study of IVD disease.

The dynamics of giant unilamellar vesicle oxidation probed by morphological transitions

We have studied the dynamics of Lissamine Rhodamine B dye sensitization-induced oxidation of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) giant unilamellar vesicles (GUVs), where the progression of the underlying chemical processes was followed via vesicle membrane area changes. The surface-area-to-volume ratio of our spherical GUVs increased after as little as ten seconds of irradiation. The membrane area expansion was coupled with high amplitude fluctuations not typical of GUVs in isoosmotic conditions. To accurately measure the area of deformed and fluctuating membranes, we utilized a dual-beam optical trap (DBOT) to stretch GUV membranes into a geometrically regular shape. Further oxidation led to vesicle contraction, and the GUVs became tense, with micron-scale pores forming in the bilayer. We analyzed the GUV morphological behaviors as two consecutive rate-limiting steps. We also considered the effects of altering DOPC and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl) (RhDPPE) concentrations. The resulting kinetic model allows us to measure how lipid molecular area changes during oxidation, as well as to determine the rate constants controlling how quickly oxidation products are formed. Controlled membrane oxidation leading to permeabilization is also a potential tool for drug delivery based on engineered photosensitizer-containing lipid vesicles.