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PubMed1975

Some effects on layers of sodium sulfate and magnesium sulfate in their drinking water.

Potential for increasing contamination of water supplies with such materials as dissolved inorganic solids suggests more precise water quanlity standards for poultry. Commercial strain S.C.W.L. hens were supplied water containing sodium sulfate (Na2SO4) or magnesium sulfate (MgSO4) (250, 1,000, 4,000, or 16,000 p.p.m.) on a total sulfate basis in Exp. 1 and on a total salt basis in Exp. 2. All data are expressed as percentages deviated from pre-treatment performance. Four thousand p.p.m. of total sulfate as Na2SO4 or MgSO4 significantly depressed feed consumption and hen-day production. Magnesium sulfate (4,000 p.p.m.) had a more depressing effect than Na2SO4 (4,000 p.p.m.) on hen-day production (-80.4 vs. -24.4%). At that level, Na2SO4 significantly increased water consumption and fecal moisture content, while MgSO4 significantly decreased water consumption. All hens on 1l,000 p.p.m. of either salt died during the experiment. No effect on egg quality was observed before the hens died. On a total salt basis (Exp. 2) 16,000 p.p.m. of either Na2SO4 or MgSO4 significantly depressed hen-day production, body weight, and feed comsumption, but increased water consumption. Hens receiving 16,000 p.p.m. Na2SO4 increased water consumption more than those receiving 16,000 p.p.m. MgSO4(146.7 and 24.6%). No significant differences between treatments were observed for mortality (Exp. 2). Mortality data suggest that lethal levels of Na2SO4 and MgSO4 are between 16,000 and 20,032 or 23,680 p.p.m. total salt, respectively.

Administration, Oral↗
PubMed2006

Investigation of sodium sulfate phase transitions in a porous material using humidity- and temperature-controlled X-ray diffraction.

Crystals growing in confined spaces can generate stress and are a major cause of damage in porous materials. To investigate such deleterious processes, appropriate in situ techniques are required. This paper describes the use of X-ray diffractometry under controlled conditions of temperature and relative humidity (RH-XRD) for the direct observation of phase transition reactions in a porous substrate. An improved environmental chamber without temperature gradients is presented and applied to the investigation of phase transformations in the system Na2SO4 + H2O. This salt is generally considered as particularly damaging and frequently used in accelerated weathering tests. It is demonstrated that RH-XRD can be successfully applied for the direct observation of several relevant phase transitions in glass frits used as porous substrates. The conversion of Na2SO4(III) to Na2SO4(V) and the hydration of Na2SO4(V) both proceed fairly rapidly as true solid-state reactions without deliquescence of the educt phases. In contrast, crystallization from solution is kinetically hindered as there is a strong tendency of aqueous Na2SO4 to form supersaturated solutions also in narrow pores. The important implications of this behavior of the salt are also briefly discussed in the paper.

Journal Article↗
PubMed2005

Scanning electrochemical microscopy in combination with piezoelectric quartz crystal impedance analysis for studying the growth and electrochemistry as well as microetching of poly(o-phenylenediamine) thin films.

The combination of scanning electrochemical microscopy (SECM) with piezoelectric quartz crystal impedance (PQCI) analysis was proposed as a novel multiparameter method for investigating the cyclic voltammetric growth of poly(o-phenylenediamine) (PoPD) thin films at Au electrodes in aqueous solutions of various pH values and the potentiostatic microetching (localized degradation) of these films in 0.10 mol/L aqueous H2SO4 for comparative examinations on polymer porosity and stability. Two potential-sweep ranges, -0.4 to 0.9 (I) and 0 to 0.9 (II) V versus SCE, and four solutions, acidic (A, 0.20 mol/L H2SO4 + 0.10 mol/L Na2SO4; B, 0.10 mol/L H2SO4 + 0.20 mol/L Na2SO4), neutral (C, 0.10 mol/L PBS + 0.20 mol/L Na2SO4, pH 7.2), and alkaline (D, 0.20 mol/L NaOH + 0.20 mol/L Na2SO4) aqueous solutions, were selected for PoPD growth. The pH increase for the polymerization solution increased the molar percentage of polyaniline-like chains in PoPD, as quantified from the current peaks at approximately 0.6 V versus a saturated calomel electrode (SCE) for the oxidation of -NH2 groups in as-prepared PoPD (grown from solutions C and D) during their redox switching in 0.10 mol/L aqueous H2SO4 for the first time. The unusual PQCI responses observed at negative potentials (potential range I) in the first several potential cycles during the cyclic voltammetric growth of PoPD in acidic and neutral solutions have been reasonably explained as being due to the precipitation/dissolution of the poorly soluble phenazinehydrine charge-transfer complexes developed during redox switching of oligomers for the first time, which brought about much less compact PoPD films and their higher degradability than those grown in the same solution but over potential range II. SECM, scanning electron microscopy (SEM), and piezoelectric quartz crystal (PQC) frequency were used to estimate the sizes of etched microscale spots. In addition, the x-, y-, or z-axis movement of a Pt microelectrode of 25-mum diameter near the PQC electrode was found to influence negligibly the PQCI responses in 1.0 mol/L aqueous Na2SO4 containing K4Fe(CN)6 up to 0.10 mol/L, and a new protocol of dynamically electrodepositing silver microwires via the chemical-lens method was proposed for examining the local mass-sensitivity distribution on the PQC surface.

Electrochemistry↗
PubMed1999

Relaxant effect of magnesium and zinc on histamine-induced bronchoconstriction in dogs.

OBJECTIVE: Magnesium sulfate (MgSO4) has been reported to produce bronchodilation in asthmatic patients. In vitro studies have suggested that divalent cations inhibit L-type voltage-sensitive calcium ion (Ca2+) channels in cardiac and smooth muscles. In this study, we evaluated the in vitro and in vivo effects of magnesium ion (Mg2+) and zinc ion (Zn2+) on the airway contracted by histamine. SETTING: A university research laboratory. SUBJECTS IN VITRO: Tracheal smooth muscle from guinea pigs. IN VIVO: Mongrel dogs. MEASUREMENTS AND MAIN RESULTS IN VITRO STUDY: The tension of isolated guinea pig tracheal strips was measured isometrically with a force displacement transducer. The specimen was contracted with histamine (10 microM). Then, MgSO4 (n = 6), zinc sulfate (ZnSO4, n = 6), or sodium sulfate (Na2SO4, n = 6) was cumulatively added to the organ bath. IN VIVO STUDY: The bronchial cross-sectional area of mongrel dogs was measured by a direct visualization method demonstrated previously. The dogs were randomly assigned to three groups: group Mg (n = 7), group Zn (n = 7), and group Na (n = 7). Bronchoconstriction was elicited with histamine (10 microg/kg plus 500 microg/kg/hr iv). Thirty minutes after the start of histamine infusion, 0 (saline), 1, 10, and 100 micromol/kg ZnSO4 or 1, 10, 100, and 1000 micromol/kg MgSO4 or Na2SO4 were administered intravenously in group Zn, Mg, or Na, respectively. The bronchial cross-sectional area was assessed before (basal) and 30 mins after the start of histamine infusion and 5 mins after each dose of ZnSO4, MgSO4, or Na2SO4. Arterial blood was also obtained to measure plasma levels of epinephrine and norepinephrine by gas chromatography-mass spectrometry. All data are expressed as mean +/- SEM. The doses of the divalent cations that reversed histamine-induced contraction by 50% were calculated by GraphPad Prism. MgSO4 and ZnSO4 (9.38+/-0.28 and 1.84+/-0.30 mM, respectively) relaxed histamine-contracted tracheal strip in a concentration-dependent manner, whereas Na2SO4 did not. Similarly, the in vivo study showed that MgSO4 and ZnSO4 dose-dependently reversed histamine-induced bronchoconstriction (potency, ZnSO4 > MgSO4), whereas Na2SO4 did not. In groups Mg and Zn, the plasma catecholamine levels also dose-dependently increased except when 1000 micromol/kg MgSO4 was administered. CONCLUSION: Because the divalent cations tested produced a spasmolytic effect on the contracted airway, infusion of divalent cations might be effective against asthmatic attack. However, high concentrations of these cations produce significant toxicity, so dosage will be an important concern in development of these agents.

Animals↗
PubMed2006

Differential effects of sodium and magnesium sulfate on water consumption by beef cattle.

The existing guidelines for maximum sulfate (SO4) in cattle drinking water are based on Na2SO4, although many water sources contain greater concentrations of MgSO4. Two experiments compared the effect of different SO4 salts on water consumption and fecal DM of cattle. In Exp. 1, 8 yearling heifers (initial BW = 345 +/- 8 kg; mean +/- SD) were watered twice daily with tapwater or water containing Na2SO4 or MgSO4 at target levels of 1,500, 3,000, or 4,500 mg of SO4/L for 2-d treatment periods separated by 2 d of access to tapwater. In Exp. 2, 16 yearling cattle (initial BW = 421 +/- 24 kg) were watered twice daily with tap-water (16 mg of SO4/L) or water containing Na2SO4 at target levels of 2,000 mg of SO4/L (low Na2SO4), MgSO4 at 2,000 mg of SO4/L (low MgSO4), or MgSO4 at 4,000 mg of SO4/L (high MgSO4) in 21-d treatment periods separated by 7-d periods on tapwater. The first 10 d of each period were allowed for adjustment to the treatment, and the final 11 d was considered the treatment period for analysis purposes. Treatments were applied in an incomplete Latin square, where each animal was exposed to 3 of the 4 treatments. In Exp. 1, the average daily water consumption decreased linearly as the SO4 concentration increased for MgSO4 (P = 0.0001) but not for Na2SO4 (P = 0.39). In Exp. 2, the average daily water consumption was less for cattle on the high-MgSO4 treatment than for cattle on the low-MgSO4 treatment (P = 0.0001), and cattle on the low-MgSO4 treatment tended (P = 0.09) to drink less than those on the tap-water treatment. Fecal DM was greater for cattle on the high-MgSO4 treatment than for those on the low-MgSO4 treatment (P < 0.01). These findings indicate that cattle reduce their consumption of water containing high (> or = 4,000 mg of SO4/L) concentrations of MgSO4, even after a given time to adjust to the treatment; such reductions may be accompanied by an increase in fecal DM.

Animals↗
PubMed2006

Electrocoagulation of synthetically prepared waters containing high concentration of NOM using iron cast electrodes.

The aim of this investigation is to evaluate the treatability of synthetically prepared water with high concentration of humic substances by electrocoagulation in batch mode using iron cast electrodes. Effects of applied potential, initial humic substance concentration and supporting electrolyte type on humic substance removal efficiency were investigated. NaNO3, Na2SO4 and NaCl were used as supporting electrolyte. Among these supporting electrolytes, Na2SO4 and NaCl have provided high removal efficiencies, whereas in the experiments using NaNO3 as supporting electrolyte have been observed no flock formation. The highest removal rate is obtainable with NaCl as supporting electrolyte. Removal efficiencies for initial humic substance concentration of 500 mg L-1 with NaCl and Na2SO4 equal to 97.95% for 35 min and 92.69% for 70 min, respectively. This behavior of the system has been derived from oxidation products, available in the bulk solution, of chloride ions. When NaCl is used as supporting electrolyte, there is an advantage of providing the disinfection of water, but humic substances and chloride ions are available in the bulk solution with risk of formation undesirable organo-chlorine compounds, so the Na2SO4 is the most favorable supporting electrolyte.

Biological Products↗
PubMed2005

Investigation of efflorescence of inorganic aerosols using fluorescence spectroscopy.

The phase transition is one of the most fundamental phenomena affecting the physical and chemical properties of atmospheric aerosols. Efflorescence, in particular, is not well understood, partly because the molecular interactions between the solute and water molecules of saturated or supersaturated solution droplets have not been well characterized. Recently, we developed a technique that combines the use of an electrodynamic balance and a fluorescence dye, 8-hydroxyl-1,3,6-pyrenetrisulfonate (pyranine), to study the distributions of solvated and free water in aqueous droplets (Choi, M. Y.; Chan, C. K.; Zhang, Y. H. J. Phys. Chem. A 2004, 108, 1133). We found that the equality of the amounts of solvated and free water is a necessary but not sufficient condition for efflorescence. For efflorescing compounds such as Na2SO4, (NH4)2SO4, and a mixture of NaCl and Na2SO4, the amount of free water decreases, while that of solvated water is roughly constant in bulk measurements and decreases less dramatically than that of free water in single-particle measurements as the relative humidity (RH) decreases. Efflorescence of the supersaturated droplets of these solutions occurs when the amounts of free and solvated water are equal, which is consistent with our previous observation for NaCl. For nonefflorescing compounds in single-particle levitation experiments such as MgSO4 and Mg(NO3)2, the amounts of free and solvated water are equal at a water-to-solute molar ratio of about 6, at which spectral changes due to the formation of contact ion pairs between magnesium and the anions occur as shown by Raman spectroscopy. Fluorescence imaging shows that the droplets of diluted Mg(NO3)2 (at 80% RH) and MgSO4 are homogeneous but those of NaCl, Na2SO4, (NH4)2SO4, and supersaturated Mg(NO3)2 (at 10% RH) are heterogeneous in terms of the solvated-to-free water distribution. The solvated-to-free water ratios in NaCl, Na2SO4, and (NH4)2SO4 droplets are higher in the outer regions by about half a radius deep than at the center of the droplets.

Journal Article↗
PubMed2004

Structure and electrochemistry of 4,4'-dithiodipyridine self-assembled monolayers in comparison with 4-mercaptopyridine self-assembled monolayers on Au(111).

4,4'-Dithiodipyridine (PySSPy) monolayers on Au(111) were investigated by cyclic voltammetry, X-ray photoelectron spectroscopy (XPS) and in situ scanning tunneling microscopy (STM). The studies were performed in solutions of different anions and pHs (0.1 M H2SO4, 0.1 M HClO4, 0.1 and 0.01 M Na2SO4, 0.1 and 0.01 M NaOH). The cyclic current-potential curves in H2SO4 show current peaks at about 0.4 V, which are absent for all other electrolytes at this potential. The XPS data suggest that PySSPy adsorbs via the S endgroup on the gold surface and the S-S bond breaks during adsorption. From the chemical shift of the N(ls) peak, it is concluded that in acidic media the self-assembled monolayer (SAM) is fully protonated, whereas in basic solution it is not. The pKa is estimated to be 5.3. STM studies reveal the existence of highly ordered superstructures for the SAM. In Na2SO4 and H2SO4, a (7 x mean square root of 3) structure is proposed. However, whereas in Na2SO4 solutions the superstructure does not change with potential, in 0.1 M H2SO4 the superstructure is observed only negative of the current peak at +0.4 V. At more positive potentials, the film becomes disordered. The results are compared to those for 4-mercaptopyridine (PyS) SAMs. XPS experiments and current-potential curves indicate that both molecules adsorb in the same manner on Au(111), that is, even in the case of PySSPy the adspecies is PyS. The STM results, however, call for a more subtle interpretation. While in Na2SO4 solutions the observed superstructures are the same for both SAMs, markedly different structures are found for PySSPy and PyS SAMs in 0.1 M H2SO4.

Journal Article↗
PubMed1976

Nitrogen retention in men fed isolated soybean protein supplemented with L-methionine, D-methionine, N-acetyl-L-methionine, or inorganic sulfate.

The ability of various sulfur-containing compounds to replace L-methionine (L-Met) was investigated by metabolic balance studies in man. N-acetyl-L-Methionine (AcMet), D-methionine (D-Met), and sodium sulfate (Na2SO4) were used to supplement a diet deficient in sulfur amino acids. The daily diet contained 4.5 g nitrogen (N) from isolated soybean protein (SB) and 4.5 g from glycine and alanine (9 g total N). SB diet was given alone or supplemented to six adult men for periods of 9 days after a standardization period with an equal N eggwhite diet, preceded by a 2-day zero N adaptation period. Supplements provided equivalent amounts of sulfur to that present in 420 ml L-Met, the amount added to SB to bring the total sulfur amino acid content to 900 mg/day. AcMet was as benfeficial as L-Met in improving N balance but D-Met was not as effective as L-Met. Difference between balances obtained with L-Met and Na2SO4 was not significant due to large variation in response to Na2SO4. While addition of D-Met to SB did not result in significantly greater N retention than unsupplemented SB, NA2SO4 addition did cause increased N retention.

Adult↗
PubMed1989

Evidence by calorimetry for an activation of sodium-hydrogen exchange of young rat skeletal muscle in hypertonic media.

1. The rate of energy dissipation associated with Na(+)-H+ exchange in isolated, superfused soleus muscles from young rats was measured with an isothermal microcalorimeter during quasi-stationary states of oxidative metabolism. 2. Under normal physiological conditions, amiloride, an inhibitor of the Na(+)-H+ exchange across plasma membranes, had no measurable effect on the specific rate of muscle heat production (E); the ouabain-suppressible part of E was identical whether amiloride was absent or present. 3. E was increased under hyperosmotic conditions and the difference with respect to control (excess E) was proportional to the degree of hyperosmolarity of the superfusate. It was 48% of basal E during a +100 mosM stress (with no change of extracellular Na+ concentration, Na+o). Inhibition of Ca2+ release into the sarcoplasm with sodium dantrolene (10(-5) M) or tetracaine (5 x 10(-5) M) suppressed a substantial part (65 and 53%, respectively) of the steady-state excess E (1.2 mW (g wet weight)-1) induced by the +100 mosM stress. Practically 100% of excess E was suppressed in the nominal absence of extracellular sodium (Na+o = 0, Li+ substitution) or under 15 mM-Na+o, and excess E was enhanced when Na+o was increased (hyperosomolarity by addition of Na2SO4 instead of sucrose). 4. Under hyperosmotic conditions, amiloride at the 5 x 10(-7) M concentration had no effect on excess E whereas at 10(-4) M it induced a significant decrease of excess E. The absolute effect of 10(-4) M-amiloride was -0.34 mW (g wet weight)-1 (equal to 28% of the excess E due to a +100 mosM-sucrose stress and to 14% of the excess E due to a +100 mosM-Na2SO4 stress). It was left unaltered in the presence of dantrolene and was independent of the way the +100 mosM stress was obtained (i.e. 100 mM-sucrose or 50 mM-Na2SO4). It was suppressed at Na+o = 0-15 mM and could be mimicked by guanochlor, another potent inhibitor of Na(+)-H+ exchange. In the presence of 10(-4) M-amiloride, the ouabain-suppressible E was significantly reduced. In the presence of ouabain, amiloride had no effect. 5. Muscle tissue space available to [3H]inulin was measured in parallel experiments. It was 23.3% under control conditions and 30.6% after a 2 h exposure of the muscle to a +100 mosM-Na2SO4 stress.(ABSTRACT TRUNCATED AT 400 WORDS)

Amiloride↗
PubMed2006

Effects of inorganic ions on the binding of triflupromazine and chlorpromazine to bovine serum albumin studied by spectrometric methods.

The effects of inorganic salts, NaCl, NaBr, NaI, Na2SO4, KCl, KBr, KI, on the binding constants (Ks) of psychotropic phenothiazine drugs, triflupromazine (TFZ) and chlorpromazine, to bovine serum albumin (BSA) were examined by using second-derivative spectrophotometry. All of the salts examined, with the exception of Na2SO4, decreased the K values significantly, depending on the concentration of the salt, e.g., the decrease in the K values of both drugs were about 40% for 0.1 M NaCl. The results obtained with Na2SO4 indicated that neither Na+ nor SO4(2-) had any affect on the binding of the phenothiazines to BSA. Based on the Na2SO4 results and the finding that the effect of each potassium salt on binding was quite similar to that of the corresponding sodium salt, the effects of these halogen salts can be considered to be derived from their anions, although the phenothiazines are positively charged at pH 7.4. The effectiveness of the anions was determined to occur in the following order: I->>Br->Cl-; these results coincided with the published order of the binding affinity of these anions to albumin. The 19F-NMR spectra of TFZ in the presence of each of these halogen salts revealed a concentration-dependent decrease in the intensity of the signal at 13.8 ppm that had previously been assigned to the TFZ bound to Site II. Consequently, the effects of these anions on the binding of positively charged phenothiazine drugs are thought to be local steric effects caused by the binding of these anions to Site II.

Antipsychotic Agents↗
PubMed2001

Prevention of morphological changes in alginate microcapsules for islet xenotransplantation.

BACKGROUND: Alginate microcapsule swelling, which occurs as a result of increased hydrophilicity owing to the Ca++ that remains after rapid chelation of the inner alginate core, is a problem in encapsulation. We have previously shown that exchange of the residual divalent Ca++ with the monovalent Na+ through the use of 6 mmol/L Na2SO4 decreases swelling in chelated alginate-polylysine-alginate microcapsules, and this process enhances their durability. The purpose of the present study was to examine the morphology of Na2SO4-treated microcapsules in long-term incubation with the use of serum-supplemented culture medium. METHODS: Spherical beads of purified alginate (3%) that were gelled with 1.1% CaCl2 were first coated with polylysine, and then with 0.24% alginate. After rapid chelation of the inner alginate core with 55 mmol/L sodium citrate, the capsules were either incubated for 30 minutes in 6 mmol/L Na2SO4 or left untreated (control). Each group of capsules was then placed in a flask containing Ham's culture medium supplemented with 20% porcine serum and incubated at 37 degrees C. RESULTS: The diameters of Na2SO4-treated capsules only increased modestly from a mean +/- SD of 635 +/- 22.08 to 684.53 +/- 17.86 microm (P<0.0001) by day 7, with no further increases thereafter. In contrast, control capsules showed a steady increase in their mean diameters, which changed from 639.55 +/- 21.44 to 735.48 +/- 108.85 microm (P < 0.0001) by day 66. In addition, whereas treated capsules remained spherical, control capsules showed progressive polymorphism. CONCLUSION: We have developed a new method of making more durable and stable microcapsules that can be used for islet cell xenotransplantation.

Alginates↗
PubMed1986

Methionine, choline and sulfate interrelationships in the diet of weanling swine.

Experiments were conducted to examine the interrelationships between methionine, choline and inorganic sulfate in the diet of weanling pigs, and to evaluate the selenium (Se) status of pigs fed diets with or without supplemental sulfate. Two trials utilized 288 weanling (3-wk-old) pigs allotted to dietary treatment based on weight, sex and litter origin. There were six pigs/pen and three replicate pens/treatment in each trial. The basal corn-soybean meal diet was formulated to supply .55% sulfur amino acids and contained a choline and sulfur-free vitamin and mineral premix. Lysine was added to provide a total of 1.13% lysine. Seven additional treatments were formulated by substituting for corn .17% DL-methionine, .29% choline dihydrogen citrate or .25% Na2SO4 to create a 2(3) factorial arrangement of treatments. There were methionine X choline X sulfate interactions for average daily gain (P less than .001) and feed-to-gain ratio (F:G; P less than .05). Adding choline, methionine, Na2SO4 or choline plus methionine to the basal diet did not improve gains. However, when Na2SO4 plus methionine or Na2SO4 plus choline were added, daily gains were increased (P less than .05) and F:G was improved (P less than .1). Addition of all three supplements did not result in a further increase in gain. Pigs fed choline-supplemented diets had higher (P less than .01) hematocrit and tended (P = .07) to have increased hemoglobin concentration. There was no effect on serum triglycerides or alkaline phosphatase activity due to dietary treatment. The concentration of Se in muscle, liver, kidney and blood was not influenced by sulfate content of the diet.

Animals↗
PubMed1977

Hydrolysis of steroid glucuronides with beta-glucuronidase preparations from bovine liver, Helix pomatia, and E. coli.

We determined the enzymic activity of beta-glucuronidase preparations from bovine liver, Helix pomatia, and Escherischia coli with steroid glucuronides and nonsteroid glucuronides as substrates. We also studied the effect of Na2SO4 on the enzymic hydrolysis of several substrates with the three preparations of beta-glucuronidase. Na2SO4 increases the rate of hydrolysis of all substrates with beta-glucuronidase from bovine liver. Hydrolysis of a steroid glucoronide with beta-glucuronidase from Helix pomatia and E. coli is inhibited by Na2SO4. None of the three enzyme preparations gives complete hydrolysis of urinary steroid conjugates, because urine contains inhibitors, which can be removed by absorption chromatography of the urine on a column of neutral polystyrene resin Amberlite XAD-2. But when Amberlite XAD-2 is not used, hydrolysis of urinary glucuronides of androsterone, etiocholanolone, pregnanediol, estriol, and 17-hydroxycorticosteroids proves that, given an incubation time of 24 h, the beta-glucuronidase preparation from bovine liver, in the presence of Na2SO4, is suited for determining all of the above steroids except esriol; the preparation from Helix pomatia is good for determining estriol and 17-hydroxycorticosteroids; the preparation from E. coli is good for determining androsterone, 17-hydroxycorticosteroids, and especially estriol, the glucuronide, of which is maximally hydrolyzed in 2 h.

17-Hydroxycorticosteroids↗
PubMed1993

The effect of sulphate on thiamine-destroying activity in rumen content cultures in-vitro.

The effect of sulphur on thiamine-destroying activity was studied in native or thiamine-spiked rumen content cultures. The treatments consisted of water [control (Ctrl)], sodium chloride (NaCl) and sodium sulphate (Na2SO4). A net gain (relative to 0 h) of thiamine in native cultures was observed for at least 48 h at levels of S ranging from 0.25 to 8 mg S added per ml of the culture and also in the Ctrl and respective NaCl cultures. However, after 48 h of incubation thiamine concentration was lower (p < 0.05) in native cultures treated with Na2SO4 relative to Ctrl and NaCl treatments. There was a linear (p < 0.03) time trend indicating an effect of Na2SO4 over time on changes in thiamine concentration in native rumen cultures. In thiamine-spiked rumen content cultures, the cultures treated with Na2SO4 produced higher (p < 0.05) thiamine-destroying activity. There was no effect of cation (Na) on thiamine-destroying activity. Initial heat treatment of thiamine-spiked cultures inactivated part of the thiamine-destroying activity. There were no differences among treatments in heat treated cultures. It is concluded that sulphate increases thiamine-destroying activity in the rumen content and the destructive mechanism involves thermolabile factor(s), however, the ruminal synthesis of thiamine is not affected by sulphate.

Animals↗
PubMed1999

Differential protein expression by Pseudomonas fragi submitted to various stresses.

We have analyzed the impact of various stressing conditions on the physiological and molecular responses of the main psychrotrophic spoilage bacterium of refrigerated meat and meat products, Pseudomonas fragi. A survival study using conventional plating was first performed to select the stressing agents and parameters. Some of these mimicked cleaning-disinfection processes but with less drastic conditions in order to keep alive enough bacterial cells for the protein expression characterization. Cultures of P. fragi, at the beginning of the stationary phase of growth, were submitted to individual pH (5.4, 10.5), osmotic (8% Na2SO4, pH 7.0), biocide (fatty amine) shocks or combined treatments (8% Na2SO4, pH 10.5; 8% Na2SO4, pH 10.5 + biocide; pH 5.4 + pH 10.5 and pH 10.5 + pH 5.4) and the molecular responses were investigated by comparing autoradiograms of two-dimensional gel electrophoresis (2-DE) patterns of proteins radiolabeled with L-[35S]methionine. The observation of qualitative and relative quantitative variations in protein expression, determined with Melanie II image analysis software (Bio-Rad), revealed the overexpression of a total of 91 proteins for the eight challenges by comparison with the nonshocked controls. Some proteins appeared to be more or less general stress proteins whereas others were specific for one chemical treatment. The appraisal of the type of molecular response according to the type of treatment was analyzed statistically.

Animals↗
PubMed1986

Thermostabilization of Inoue-Melnick virus by salt.

Inoue-Melnick virus (IMV) was stabilized to thermal inactivation at 50 degrees C by 1 M Na2SO4 but not by 1 M MgCl2, 1 M MgSO4, 2 M NaCl, and 2 M KCl. The latter salts enhanced the inactivation over that in distilled water. Na2SO4 stabilized IMV at 1 M concentration but enhanced inactivation at 0.1 M. Three types of IMV were stabilized by 1 M Na2SO4 at 50 degrees C to almost the same degree. The pattern of the thermostabilization of IMV by salts was similar to that of herpes simplex virus; however, the degree of its stabilization was lower with prolonged heating.

Herpesviridae↗
PubMed1996

Cosolvent-induced adsorption and desorption of serum proteins on an amphiphilic mercaptomethylene pyridine-derivatized agarose gel.

We studied the effects of the following cosolvents on the adsorption and desorption of serum proteins from an amphiphilic mercaptomethylene pyridine-derivatized agarose gel: glucose, sucrose, polyethylene glycol (PEG), 2-methyl-2,4-pentanediol (MFD), sorbitol, pentaerythritol, glycerol, and Na2SO4. The water-structuring salt 0.4 M Na2SO4 was the most potent promoter of protein adsorption, followed by 5 M sorbitol and, to a lesser extent, 0.2 M PEG 1000 and 2.25 M MPD. The other cosolvents (4 M glucose, 1.5 M sucrose, 0.3 M pentaerythritol, and 7.6 M glycerol) were unable to promote protein adsorption to the gel. Attempts to modulate the salt-promotion effect of Na2SO4 with different cosolvents demonstrated the occurrence of synergistic effects for pentaerythritol, sorbitol, and glucose and antagonistic effects for the other cosolvents. Sorbitol and glycerol were found to be the most interesting co-solvents studied, as the first promoted protein adsorption, whereas the other disrupted protein interaction. As a consequence of these novel findings we propose sorbitol and glycerol, both well-known protein stabilizers, as possible alternatives to water-structuring salts during the adsorption phase and to deleterious organic solvents during the desorption phase on amphiphilic gels.

Adsorption↗