High Concentrations Of Sodium Chloride Research Articles

Effect of Temperature, pH, and Water Activity on Biofilm Formation by Salmonella enterica Enteritidis PT4 on Stainless Steel Surfaces as Indicated by the Bead Vortexing Method and Conductance Measurements

An assay was developed in an effort to elucidate the effect of important environmental parameters (temperature, pH, and water activity [aw]) on Salmonella Enteritidis biofilm formation on stainless steel surfaces. To achieve this, a modified micro-biological technique used for biofilm studying (the bead vortexing method) and a rapid method based on conductivity measurements were used. The ability of the microorganism to generate biofilm on the stainless surfaces was studied at three temperatures (5, 20, and 37°C), four pH values (4.5, 5.5, 6.5, and 7.4), and four aw values (0.5, 1.5, 5.5, and 10.5% NaCl). Results obtained by the bead vortexing method show that maximum numbers of adherent bacteria per square centimeter (106 CFU/cm2) were attained in 6 days at 20°C. Biofilm formation after 7 days of incubation at 20°C was found to be independent of the pH value. In addition, the high concentration of sodium chloride (10.5% NaCl, aw = 0.94) clearly inhibited the adherence of cells to the coupons. Conductance measurements were used as a supplementary tool to measure indirectly the attachment and biofilm formation of bacterial cells on stainless steel surfaces via their metabolic activity (i.e., changes in the conductance of the growth medium due to microbial growth or metabolism). Results obtained by conductance measurements corresponded well to those of the bead vortexing method. Furthermore, we were able to detect cells that remained attached on the metal surfaces even after vortexing via their metabolic activity. The results, except for demonstrating environmental-dependent Salmonella Enteritidis biofilm formation, indicated that traditional vortexing with beads did not remove completely biofilm cells from stainless steel; hence, conductance measurements seem to provide a more sensitive test capable to detect down to one single viable organism.

Treatment and reuse of reactive dyeing effluents

Industrial textile processing comprises the operations of pretreatment, dyeing, printing and finishing. These production processes are not only heavy consumers of energy and water; they also produce a substantial amount of chemical pollution. Of all dyed textile fibres, cotton occupies the number-one position, and more than 50% of its production is dyed with reactive dyes, owing to their technical characteristics. Unfortunately, this class of dyes is also the most unfavorable one from the ecological point of view, as the effluents produced are relatively heavily colored, contain high concentrations of salt and exhibit high BOD/COD values. Dyeing 1 kg of cotton with reactive dyes requires an average of 70–150 L water, 0.6 kg NaCl and 40 g reactive dye. The composition of the dye bath which we propose to treat contains solid particles (cotton fibres), dyeing auxiliaries (organic compounds), hydrolyzed reactive dyes, substantial quantities of alkalis (sodium carbonate and soda ash) and very high concentration of sodium chloride or sodium sulfate. This paper presented the state of the art of the different processes currently used for the treatment of dye house wastewaters and evaluated a four-step process [1] to recover the water and the mineral salts, while leaving the spent dyes in the reject stream. Processes evaluated included (1) cartridge filtration to remove textile fibres, (2) acidification to make the brine recovered, suitable for reuse and further dyeing operations, (3) nanofiltration (NF) to concentrate the hydrolyzed dyes and (4) reverse osmosis (RO) to further concentrate the salts for reuse in the dyeing process. A cut-off of 100 μm is sufficient to trap textile fibres, regardless of the type of effluent and the texture of the textile dyed. The hydrolyzed reactive dyes present in the treated effluents comprise the entire range of possible types of reactive dyes. For this acidification, we studied the influence of the concentration of sodium chloride, the influence of the temperature and we verified that the volume neither depends on the concentrations of reactive hydrolyzed dyes nor sodium chloride. After defining the nanofiltration membrane, we studied the effect of the pH, temperature, pressure and velocity as well as the experimental procedure on the permeate flux, recovery of the salt and removal of the color. An increase of either of the parameters temperature and pressure leads to an increase of the permeate flux. On the other hand, a rise in the pH leads to a decrease of the permeate flux. The retention factor of the sodium chloride is low when the concentration of sodium chloride is high in the retentate. Our aim was to recover 80–90% of the sodium chloride, but our experiments showed that the recovery went as high as 99%. Depending on the dyes used, the experimental procedure can be carried out in one, two or three steps. The dye retention level was always higher than 98%. After studying the operating variables, experiments with the recycled brines in new dyeing operations were carried out with specimen dyeings prepared with usual water using different classes of reactive dyes. There was no difference in the results in terms of depth, shade or fastness properties, whichever type of water was used. These last results therefore validate our process and its special innovative feature: recycling not only the water but also the mineral salts.

Ferrite supports for isolation of DNA from complex samples and polymerase chain reaction amplification

The influence of cobalt ferrite particles, with non-modified or modified surface, on the course of polymerase chain reaction (PCR) was investigated. DNA isolated from bacterial cells of Bifidobacterium bifidum was used in PCR evaluation of magnetic microspheres. The presence of cobalt ferrite particles inhibits PCR amplification. The effect is not dependent on the functional groups of the modifying reagents used (none, amino, carboxyl). Amplification was improved after the magnetic separation of magnetic particles. Proposed indirect method enabled verification of the suitability of designed particles for their application in PCR assays. Magnetic particles coated with alginic acid under high PEG and sodium chloride concentration were used for the isolation of PCR-ready bacterial DNA from various dairy products. DNA was isolated from crude bacterial cell lysates without phenol extraction of samples. Bifidobacterium and Lactobacillus DNAs were identified in dairy products using PCR.

Organoclay Formulations of Acetochlor: Effect of High Salt Concentration

This study aimed to evaluate new methodology for designing ecologically acceptable formulations of acetochlor. Modification of montmorillonite with phenyltrimethylammonium chloride (PTMA) or benzyltrimethylammonium chloride (BTMA) and organoclay formulations of acetochlor were prepared in the presence of high concentrations of sodium chloride (150 g/L). Acetochlor concentration in the equilibrium solutions was determined by HPLC. Release of acetochlor in a water system was performed by a funnel experiment. Leaching of acetochlor in soil was determined by a bioassay using a column technique and Setaria viridis as a test plant. The adsorbed amounts of acetochlor on montmorillonite exchanged by PTMA or BTMA were increased as NaCl concentration increased in the equilibrium solution. Leaching of acetochlor from organoclay formulations was significantly inhibited to the top soil layer (0-5 cm) when the formulations were prepared at extreme NaCl concentration (100-150 g/L). These results are in accord with a funnel experiment that showed a reduction in acetochlor release from the montmorillonite-based formulations. The application of this method for herbicide formulation would produce ecologically acceptable herbicide formulations that can significantly minimize the risk to groundwater pollution.

Differential Activation of eIF2 Kinases in Response to Cellular Stresses in Schizosaccharomyces pombe

Phosphorylation of eukaryotic initiation factor-2 (eIF2) is an important mechanism mitigating cellular injury in response to diverse environmental stresses. While all eukaryotic organisms characterized to date contain an eIF2 kinase stress response pathway, the composition of eIF2 kinases differs, with mammals containing four distinct family members and the well-studied lower eukaryote Saccharomyces cerevisiae expressing only a single eIF2 kinase. We are interested in the mechanisms by which multiple eIF2 kinases interface with complex stress signals and elicit response pathways. In this report we find that in addition to two previously described eIF2 kinases related to mammalian HRI, designated Hri1p and Hri2p, the yeast Schizosaccharomyces pombe expresses a third eIF2 kinase, a Gcn2p ortholog. To delineate the roles of each eIF2 kinase, we constructed S. pombe strains expressing only a single eIF2 kinase gene or deleted for the entire eIF2 kinase family. We find that Hri2p is the primary activated eIF2 kinase in response to exposure to heat shock, arsenite, or cadmium. Gcn2p serves as the primary eIF2 kinase induced during a nutrient downshift, treatment with the amino acid biosynthetic inhibitor 3-aminotriazole, or upon exposure to high concentrations of sodium chloride. In one stress example, exposure to H(2)O(2), there is early tandem activation of both Hri2p and Gcn2p. Interestingly, with extended stress conditions there is activation of alternative secondary eIF2 kinases, suggesting that eukaryotes have mechanisms of coordinate activation of eIF2 kinase in their stress remediation responses. Deletion of these eIF2 kinases renders S. pombe more sensitive to many of these stress conditions.

The survival mechanism of dune reed (Phragmites communis) cultures under high sodium chloride concentration

Adaptations to salt stress were studied in embryogenic cultures from two ecotypes of reed (Phragmites communisT.). In the 600 mM NaCl treatment, relative cell viability of dune reed embryogenic cultures from a desert region was 56% greater than the control, 198% greater than swamp reed embryogenic cultures. After treatment with different NaCl concentrations, their relative growth rates (RGRs), pyridine nucleotides, activities of antioxidant enzymes and plasma membrane H+-ATPase (EC 3.6.1.35) were determined. The results showed that NADPH content, NADPH/NADP+ ratio and the activity of plasma membrane H+-ATPase in dune reed embryogenic cultures were higher than those of the control in the present of 600 mM NaCl. The activities of peroxidase (POD, EC 1.11.1.7) and catalase (CAT, EC 1.11.1.6) increased more in dune reed embryogenic cultures than in swamp reed embryogenic cultures. Dune reed embryogenic cultures tolerated higher concentration of NaCl than swamp reed embryogenic cultures. Under high concentration of NaCl, the survival of dune reed embryogenic cultures might be due to reductive status maintenance and ions absorption regulation in the plant cells. This phenomenon would be a result of cross-adaptation in nature.

Pass the Salt

Sodium is the most abundant extracellular ion. Historically, therapy with hypertonic saline was widely used for a variety of conditions. Currently, there are 3 primary indications for its use in critical care: hyponatremia, volume resuscitation, and brain injury. SIADH and CSW syndrome may require sodium replacement, but most cases of hyponatremia can be managed without administration of hypertonic saline. Studies of use of hypertonic saline in hypovolemia and brain injury are promising, but additional research is needed to better define optimal dosing regimens and to determine the relative risks associated with hypertonic saline versus conventional treatment for the management of patients with head injuries and for volume resuscitation in shock states.

Accumulation of trehalose in the thermophilic fungus Chaetomium thermophilum var. coprophilum in response to heat or salt stress

The disaccharide trehalose, known to be an effective protectant against various kinds of stress, was observed to accumulate in the cytosol of Chaetomium thermophilum var. coprophilum during heat stress. Trehalose was apparently neither involved in the defence of C. thermophilum var. coprophilum against high concentrations of sodium chloride nor directly linked to thermophily. In C. thermophilum var. coprophilum three different trehalose hydrolyzing activities were eluted from a mono Q anion exchange column by sodium chloride concentrations of 0.10, 0.15 and 0.24 M, respectively.

Lambs grazed on saltbush are more hydrated at slaughter

Dehydration in livestock before slaughter not only compromises animal welfare, but reduces carcass yields and reduces profits to farmers and abattoir processors. Dehydration is attributed to a failure to drink in lairage. Strategic feeding with saltbush may prevent the dehydration of lambs before slaughter. Saltbush, which is widely used to revegetate saline land, has high concentrations of sodium chloride. Ingesting a high sodium diet is known to increase the ionic concentration of the extracellular fluid and stimulate the lamb’s thirst. In this work, we tested the hypothesis that if the lambs maintain the high water requirement when they arrive in lairage, and consequently drink more water, they will be more hydrated and have less carcass shrinkage. Urine specific gravity, muscle dry matter percentage and urine weight are considered to be useful indicators of the hydration status of lambs (Pethick et al. 2003). High urine specific gravity (USG) occurs when the urine is concentrated. Concentrating the urine is a physiological mechanism used by an animal to conserve water when dehydrated. This study was conducted 20 km from Goomalling, Western Australia. Fifty (2 x 25) 6 month old merino lambs (average liveweight of 38 kg) grazed either a saltbush-dominant saline pasture or a ‘control’ barley stubble/pasture plot. Both groups were supplemented with approximately 200 g/d of barley grain. Following 14 weeks of grazing, the lambs were commercially slaughtered after undergoing a 24 hour period in farm curfew, followed by transport to the abattoir and 24 hours in lairage. After slaughter, 2 g samples of the m. semimembranosus (SM) and the m. semitendinosus (ST) were taken and used to calculate muscle dry matter percentage. The bladder of each sheep was also collected after slaughter and the urine extracted, weighed and a sample taken to determine USG.

Studies of the carbohydrate-carbohydrate interaction between lactose and GM(3) using Langmuir monolayers and glycolipid micelles.

This paper describes studies of the carbohydrate-carbohydrate interaction (CCI) between micelles of a lactosyl lipid and monolayers of the glycosphingolipid GM(3). The lactose Lac.GM(3) interaction is involved in B16 melanoma cell adhesion and signaling processes, and a thorough understanding of the molecular details of this CCI is important for the design of new anti-adhesive and anti-metastatic agents. In this paper, we examine the influence of variations in divalent cations and subphase ionic strength on the Lac.GM(3) interaction. Our results indicate that, in the absence of divalent cations, the Lac.GM(3) CCI is strengthened at higher sodium chloride concentrations in the subphase. In contrast, when divalent cations are present in solution, the CCI is not as sensitive to ionic strength. These results suggest a role for both cation dependent as well as independent interactions in the Lac.GM(3) CCI.

Characterization of polyimide foams after exposure to extreme weathering conditions

The weathering degradation of three closely related polyimide foams was studied by X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared (FT-IR) spectroscopy, Raman spectroscopy, Thermogravimetric Analysis (TGA) and Thermomechanical Analysis (TMA) after exposure at the NASA Kennedy Space Center's (KSC) Beach Corrosion Site. These foams were developed by NASA Langley Research Center for applications such as cryogenic insulation, flame retardant panels and structural subcomponents. The degradative environmental conditions at the KSC corrosion site include exposure to sunlight, exposure to changes in temperature and humidity, mechanical erosion by wind and rain, and high sodium chloride content due to the close proximity of the ocean. Other possible atmospheric contaminants include hydrogen sulfide and hydrogen chloride (the latter originating with exhausts from the launching of space vehicles). The foams were studied for a total of 17 months exposure, with samples taken at 3, 9 and 17 months. Data analyses of the weathered foams showed that chemical structure and density effects were the key variables in weathering performance. The carbonyl linkage in the dianhydride of the TEEK-L series polyimide foams is the most important factor in degradation. TEEK-H series foams, which contain an ether linkage in the dianhydride, showed much less degradation or more resistance to weathering in comparison to the TEEK-L series. In the same chemical series, the lower density foams were more degraded in comparison to higher density foams.

Stability of an organoclay complex: effects of high concentrations of sodium chloride

This study tests the stability of an organoclay complex (clay–BTMA0.5) and its adsorption capacity for a non-ionic organic chemical under various sodium chloride (NaCl) concentrations. Adsorption of benzyltrimethylammonium (BTMA) to montmorillonite and its desorption from the organoclay complex under various NaCl concentrations were measured. Results showed a decrease in the amount of BTMA adsorbed as the NaCl concentration increased from 0 to 100 g/l. Release of BTMA from the organoclay complex (clay–BTMA0.5) increased as NaCl concentration reached 100 g/l; however, desorption of BTMA was always less than 10% of the adsorbed amount. Solutions of BTMA increased the solubility of phenanthrene in water. Adsorption of phenanthrene by the clay–BTMA0.5 increased as NaCl concentration increased. Addition of NaCl to the system further increased the adsorbed amount of phenanthrene. These results indicate the stability of the organoclay complex (clay–BTMA0.5) under various NaCl concentrations and that its adsorption capacity towards phenanthrene was not significantly affected. Thus, the use of clay–BTMA0.5 may be useful in attenuating the concentration of organic pollutants as phenanthrene from distilled or saline water.

The effect of organic osmoprotectors on Aeromonas trota and A. hydrophila grown under high sodium chloride concentrations

The effect of organic solutes on the growth of Aeromonas trota and A. hydrophila was evaluated. Proline and glutamic acid were not effective as osmoprotectors, but betaine exerts osmoprotection allowing the growth of both strains in inhibitory concentrations of NaCl. Growth kinetics suggests that the halotolerance difference between the strains is associated with the synthesis of osmolytes rather than betaine uptake.

Chalk–fluid interactions with glycol and brines

Mechanical properties of high porosity chalks are strongly dependent on the type of fluid in the pores. Dry chalk is considerably stronger than water-saturated chalk, and this phenomenon is often referred to as the water-weakening effect. To address the problem of chalk–fluid interactions, several series of tests have been performed with glycol and high concentration brines as saturating fluids. Glycol is a fluid that in many aspects resembles oil, except that glycol is miscible with water. Glycol-saturated chalk turns out to have properties very similar to oil-saturated chalk. Compared to dry chalk, both oil and glycol make the chalk somewhat weaker, but this weakening effect is much less than with water. Several series of tests with brines with high concentrations of calcium chloride or sodium chloride show that the water-weakening effect is considerably reduced in high ionic strength solutions. Most tests were performed as quasi-hydrostatic tests, with a constant stress ratio of 0.9. In such tests, the yield point marks the onset of accelerated pore collapse, and the yield value is close to the hydrostatic yield stress. In addition to these compressive tests, a series of Brazilian tests were performed, revealing the same trend. The variations in mechanical strength have been correlated with the activity of water in the brines. Within the experimental accuracy of the compressive tests, there is a linear trend between reduction of water activity and the corresponding increase in strength. This leads to the hypothesis that the water activity may be a key parameter in the water-weakening mechanism. But this conclusion also indicates that water weakening may be a special case of general chalk–fluid interactions where the degree of weakening depends on the strength of adsorption of the fluid molecules to the calcite surfaces.

Dual stacking of unbuffered saline samples, transient isotachophoresis plus induced pH junction focusing.

A dual stacking mechanism based on transient isotachophoresis (TITP) and induced pH junction focusing is demonstrated as a means to increase the concentration sensitivity in capillary electrophoresis of highly saline samples. When stacking was carried out with an unbuffered saline sample of fluorescein between two zones of low mobility background electrolyte at high pH under an electric field of reverse polarity, two transient peaks at both boundaries of the sample zone were observed. One peak at the rear boundary could be inferred as a transient isotachophoretic stacked zone. Through computer simulations of an unbuffered sample with a high concentration of sodium chloride, we showed that the fast moving zones of sodium and chloride ions induced pH changes at both boundaries to satisfy the electroneutrality condition and that the peak at the front boundary was due to the induced pH junction. To verify the pH changes, an indicator, thymol blue, was added to an NaCl solution and the color changes under an electric field were observed. The proposed mechanism was supported by observing the dual stacking procedure for an unbuffered sample of 4-nitrophenol and measuring additional sensitivity enhancements by dual stacking for ten weakly acidic compounds. For the ten analytes including nucleoside phosphates, every dual stacking of an unbuffered sample exhibited an additional enhancement up to 86% larger than that of usual transient isotachophoresis of the corresponding buffered sample without loss of separation efficiency and reproducibility. Therefore, it would be useful to skip over buffering in sample preparation for TITP, contrary to the general recommendation.

Isolating conifer DNA: A superior polysaccharide elimination method

Genomic DNA was isolated from frozen needles of maturePinus radiata clones using a modified extraction technique incorporating cetyltrimethylammonium bromide (CTAB) for cell lysis. A high sodium chloride concentration (2 M) was used at 2 stages of the extraction procedure to eradicate polysaccharides, yielding pure genomic DNA suitable for restriction enzyme digestion and PCR amplification. Extractions were scaled down to suit 1.5-mL Eppendorf tubes, allowing easier handling and enhanced sterility.

A note on the geochemical aspects of the Harrogate mineral waters

Three new water supply boreholes have been drilled in Harrogate and extend the available information on the hydrogeology of the mineral water springs. The water chemistry, combined with the geological evidence, shows that they tap waterat the opposite ends of the mineralized groundwater evolution system. Groundwater chemistry in the recharge area is available for the first time and there is new evidence that the deep migration of mineralized waters extends further than has been found hitherto. A conceptual model for the groundwater circulation system has been developed and a possible source of the high sodium chloride content is postulated.

Stress response of Listeria monocytogenes isolated from cheese and other foods

The responses to pH and sodium chloride of four strains of Listeria monocytogenes isolated from Portuguese cheese, with a sodium chloride concentration of about 2% (w/v) and a pH value from 5.1 to 6.2, were studied. Two isolates from meat and two clinical isolates related to food-borne listeriosis, in which the implicated food product had about 2–3.5% (w/v) sodium chloride, also were studied. The effect of temperature on pH and sodium chloride sensitivity was also determined. The results show that natural isolates vary in response to these stresses and the data were often at variance with previously published data. Strains varied in sensitivity to low pH and to high sodium chloride concentration but the cheese isolates tended to be more resistant. A lower temperature was associated with a decrease in resistance to low pH and to sodium chloride. All strains showed an acid tolerance response induction when grown at pH 5.5 and although the time required for maximum induction of the response varied between strains, 2 h of acid adaptation, at least, was necessary which is longer than previously reported. Some strains showed an osmotolerance response after incubation in 3.5% (w/v) sodium chloride. Osmoadaptation, in addition to inducing an osmotolerance response, also induced cross-protection against acid shock conditions (pH 3.5). The acid tolerance response also induced a cross-protection against osmotic shock conditions (20% (w/v) sodium chloride). In some cases there was a relationship between the degree of resistance and adaptation, but usually the behaviour of a particular strain was independent of the conditions from which it was isolated.

Influence of ionic inorganic solutes on self-assembly and polymerization processes related to early forms of life: implications for a prebiotic aqueous medium.

A commonly accepted view is that life began in a marine environment, which would imply the presence of inorganic ions such as Na+, Cl-, Mg2+, Ca2+, and Fe2+. We have investigated two processes relevant to the origin of life--membrane self-assembly and RNA polymerization--and established that both are adversely affected by ionic solute concentrations much lower than those of contemporary oceans. In particular, monocarboxylic acid vesicles, which are plausible models of primitive membrane systems, are completely disrupted by low concentrations of divalent cations, such as magnesium and calcium, and by high sodium chloride concentrations as well. Similarly, a nonenzymatic, nontemplated polymerization of activated RNA monomers in ice/eutectic phases (in a solution of low initial ionic strength) yields oligomers with > 80% of the original monomers incorporated, but polymerization in initially higher ionic strength aqueous solutions is markedly inhibited. These observations suggest that cellular life may not have begun in a marine environment because the abundance of ionic inorganic solutes would have significantly inhibited the chemical and physical processes that lead to self-assembly of more complex molecular systems.

Current-voltage behaviour of bipolar membranes in concentrated salt solutions investigated with chronopotentiometry

Chronopotentiometry is used as a tool to obtain detailed information on the transport behaviour of the bipolar membrane BP-1 in solutions of high sodium chloride concentration above the limiting current density. We discuss critically the interpretation of the observed transition times. The occurrence of two such polarization times for low to moderate current densities is explained by the membrane asymmetry: the two membrane layers of opposite charge in general have different transport properties such as co-ion concentration and diffusion coefficient. The reversible and irreversible contributions to the transmembrane potential can be distinguished which allows the bipolar membrane energy requirements to be addressed. The experiments indicate that the increased voltage drop across bipolar membranes observed with higher solution concentrations can be explained on the basis of stronger concentration gradients in the membrane layers. The gradients become stronger with increased current density, but here the ohmic resistance under steady state transport conditions (the transport resistance) contributes to the increasing electrical potential. The transport resistance decreases with increasing current density due to the ion-exchange of the salt counter ions with the water splitting products. The experiments show that bipolar membranes should be operated at low current densities and low concentrations to minimize energy requirements. These findings are in contrast to the high current densities required to reduce impurities in the produced acid and base.