Decreasing NaCl Concentration Research Articles

Effect of extraction condition on technological properties of protein from Protaetia brevitarsis larvae

Alternative food sources are garnering increasing interest owing to overpopulation and environmental stresses. Edible insects are a promising alternative protein source. In this study, we evaluated the effect of pH and NaCl concentration on the quality and technical properties of extracted Protaetia brevitarsis protein. Nine different solutions were used to extract edible insect protein (pH 1, 4, 7, 10, and 14 and 0, 0.1, 0.5, and 1 M NaCl). The pH of the extracted protein increased with increasing pH (1.12±0.02 to 12.81±0.03) and decreasing NaCl concentration (6.52±0.02 to 6.89±0.01). Colour difference increased when deviating from neutral pH and 0 M NaCl. Further, surface hydrophobicity (μg) and solubility (mg/ml) of the protein decreased at pH 1 (12.25±1.39 μg and 0.74±0.08 mg/ml) and 14 (20.62±1.48 μg and 0.18±0.02 mg/ml) compared with pH 7 (71.81±1.76 μg and 1.26±0.22 mg/ml). Higher pH and NaCl concentrations yielded higher thermal stability. Foaming capacity was the highest at 0.5 (110.5±0.71%) and 1 M (100.5±10.61%) NaCl, and pH 14 (122.5±3.54%), followed by that at pH 1 (72.50±3.54%), although with low stability. Furthermore, emulsifying capacity and stability of the protein increased when deviating from pH 4. Therefore, the protein of P. brevitarsis had high functionality when extracted at highly alkaline conditions using NaCl.

PVA Cryogel as model hydrogel for iontophoretic transdermal drug delivery investigations. Comparison with PAA/PVA and PAA/PVP interpenetrating networks

The use of polyvinyl alcohol (PVA) cryogel as a model hydrogel for iontophoretic transdermal investigations is proposed. Due to the excellent combination of its properties, it could be used for evaluating iontophoretic transdermal delivery of variety of drugs, regardless of pKa, pH or presence of auxiliary ions. Applicability of PVA Cryogel for drug delivery purposes was compared to those of polyacrylic acid/polyvinyl alcohol (PAA/PVA) and polyacrylic acid/polyvinylpyrrolidone (PAA/PVP) adhesive interpenetrating networks. Swelling properties of PVA Cryogel were shown to be almost independent on pH and NaCl concentration, while swelling of PAA-based gels was significantly affected. Addition of PVA and PVP to PAA decreased swelling degrees and increased adhesivity and compression moduli. Iontophoretic experiments were performed using a donor gel/skin/receptor gel configuration; current density and delivery duration were varied. Dexamethasone sodium phosphate was used as model drug molecule. PVA Cryogel was used for investigating the influence of NaCl concentration, which can alter the amount of current carried by the drug ions and, therefore, the delivery rate. By using PVA Cryogel it was possible to easily determine the amount of drug permeated through the skin into the receptor gel, the amount retained by the skin and the amount remained in the donor hydrogel. Decreasing NaCl concentration in PVA Cryogel resulted in higher total amounts of drug delivered and significantly enhanced drug permeation through the lower layers of the skin into the receptor hydrogel.

Experimentation and modeling of surface chemistry of the silica-water interface for low salinity waterflooding at elevated temperatures

Models predicting wettability alteration of mineral-brine-oil interfaces during low-salinity-waterflooding (LSW) should account for the elevated temperatures typically found in oil reservoirs. For the first time, high temperature ζ-potential (zeta potential) data for silica are collected and used to interpret surface chemistries and interactions at reservoir-like conditions to predict temperature’s effect on wettability alteration. Mobility data for amorphous silica in varying NaCl(aq) concentrations at 25, 100, and 150 °C and neutral pH were obtained through microelectrophoresis experiments. Calculated ζ-potentials were fit with surface complexation model (SCM) parameters to predict electrical double layer (EDL) parameters based upon the Gouy-Chapman-Stern-Grahame (GCSG) model. ζ-potentials increased with increasing temperature (around 50% increase from 25 to 150 °C) and decreasing NaCl concentrations (10−1–10−4 mol kg−1). These trends, along with Derjaguin-Verwey-Landau-Overbeek (DLVO) theory, suggests that overall repulsive forces extend farther from the surface at low salinity and higher temperatures, implying greater wetting thickness/surface wettability in these environments. The resulting surface concentration calculations suggest that LSW is most impactful up to 10−2 mol kg−1 of salt, and that additional dilution below 10−3 mol kg−1 will negligibly impact oil recovery, particularly at reservoir temperatures above 100 °C. The analysis provides a framework for treating more complex reservoir systems, such as carbonates in multivalent brines.

Adsorptive removal of ammonium ion from aqueous solution using surfactant-modified alumina

Environmental contextAmmonium ion, an inorganic pollutant in agricultural land, can induce eutrophication, impacting on water quality. We investigate the adsorption of ammonium ion on surfactant-modified alumina and demonstrate highly efficient removal of ammonium ions by the alumina from two agricultural water samples. Adsorption mechanisms are also proposed based on adsorption isotherms, surface modification and the change in surface charge. AbstractThe adsorptive removal of ammonium ions (NH4+) from aqueous solution using surfactant-modified alumina (SMA) was investigated. The optimum NH4+ adsorption removal conditions on SMA were systematically studied and found to be pH 4, contact time 180min, adsorbent dosage 30mgmL–1 and ionic strength 1mM NaCl. The equilibrium concentration of NH4+ was measured by capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) and spectrophotometry. Surface modification of α-Al2O3 with the anionic surfactant sodium dodecyl sulfate (SDS) at high salt concentration induced a significant increase of removal efficiency. The change in surface charge and surface modification of α-Al2O3 by pre-adsorption of SDS and subsequent adsorption of NH4+ were evaluated by zeta potential measurements and Fourier-transform infrared spectroscopy. Under optimum adsorption conditions, NH4+ removal from two agricultural water samples achieved very high removal efficiencies of 99.5 and 96.5%. The adsorption of NH4+ onto SMA increases with decreasing NaCl concentration because desorption of SDS from the α-Al2O3 surface is minimised. Experimental results of NH4+–SMA adsorption isotherms at different ionic strengths can be represented well by a two-step adsorption model. Based on adsorption isotherms, surface charge effect and surface modification, we suggest that the adsorption mechanism of NH4+ onto SMA was mainly electrostatic attraction between cationic NH4+ and the negatively charged SMA surface.

Photodegradation of benzene and phenanthrene in aqueous solution using pulsed ultraviolet light

This study examined the comparative degradation of benzene and phenanthrene using a pulsed ultraviolet light (PUV) reactor. The concentration of free chlorine was determined for various NaCl concentrations (0-10 mM) and electrode distances (10, 20, and 40 cm) in order to investigate the effect of oxidation by free chlorine on degradation. It was observed that the presence of NaCl had a dual effect on benzene removal, while phenanthrene removal increased with decreasing NaCl concentration. Both benzene (0.065 min−1) and phenanthrene (0.24 min−1) pseudo first-order rate constants were highest with a NaCl concentration of 0.25 mM and an electrode distance of 10 cm. The degradation of phenanthrene was much higher than that of benzene due mainly to smaller Dewar's reactivity values ranging from 1.80 to 2.18 at five different positions for phenanthrene compared to the one position of benzene (2.31), which suggests that phenanthrene is more easily attacked than benzene.

Examination of the dynamic assembly equilibrium for E. coli ClpB.

Escherichia coli ClpB is a heat shock protein that belongs to the AAA+ protein superfamily. Studies have shown that ClpB and its homologue in yeast, Hsp104, can disrupt protein aggregates in vivo. It is thought that ClpB requires binding of nucleoside triphosphate to assemble into hexameric rings with protein binding activity. In addition, it is widely assumed that ClpB is uniformly hexameric in the presence of nucleotides. Here we report, in the absence of nucleotide, that increasing ClpB concentration leads to ClpB hexamer formation, decreasing NaCl concentration stabilizes ClpB hexamers, and the ClpB assembly reaction is best described by a monomer, dimer, tetramer, hexamer equilibrium under the three salt concentrations examined. Further, we found that ClpB oligomers exhibit relatively fast dissociation on the time scale of sedimentation. We anticipate our studies on ClpB assembly to be a starting point to understand how ClpB assembly is linked to the binding and disaggregation of denatured proteins.

Separation of Oil from Oil–Water Emulsions by Electrocoagulation in an Electrochemical Reactor with a Fixed-Bed Anode

In separation of oil from oil–water emulsion by electrocoagulation in an electrolytic cell with a fixed-bed anode which is made of randomly packed aluminum cylinders in a perforated plastic basket, the cathode was a horizontal aluminum plate placed below the bed anode at the cell bottom. The effects of different variables such as current density, bed height, cylinder diameter, NaCl concentration on the rate of oil removal, and electrical energy consumption were studied. Under optimum conditions, the separation efficiency reached 85 % after 5 min and a maximum of 99 % after 35 min. The rate of oil removal and oil separation efficiency increased with increasing the current density and NaCl concentration. Increasing bed height was found to increase the rate of oil removal and separation efficiency. It was also found that there was an optimum (cylinder diameter) at which the rate of oil removal and separation efficiency were higher than those at other diameters. Electrical energy consumption, which ranged from 0.35 to 27.5 kW h/kg of oil removed, was found to increase with increasing the current density, bed height and decreasing NaCl concentration. Energy consumption was found to decrease at optimum cylinder diameter. For 99 % oil removal, Al consumption under the present range of conditions ranged from 0.017 to 0.34 g/L of emulsion and the amount of sludge ranged from 0.55 to 1.48 g/L depending on the operating conditions. Comparison of the performance of the present cell with traditional cells shows that the present cell is superior to traditional cells such as the vertical parallel plate cell.

Adsorption characteristics of anionic azo dye onto large α-alumina beads

Adsorption of anionic azo dye, new coccine (NC), onto large α-alumina beads in aqueous media was systematically investigated as functions of pH and NaCl concentration. Adsorption amounts of NC decrease with increasing pH of solutions due to less positive charges of α-Al2O3 surface at high pH. At a fixed pH, the NC adsorption increases with decreasing NaCl concentration, indicating that NC molecules mainly adsorb onto α-Al2O3 by electrostatic attraction. Experimental results of NC adsorption isotherms onto α-Al2O3 at different pH, and ionic strength can be represented well by two-step adsorption model. The effects of NC on surface charge and surface modification of α-Al2O3 at the plateau adsorption are evaluated by streaming potential and Fourier transform infrared spectroscopy with attenuated total reflection technique (FTIR-ATR), respectively. On the basis of adsorption isotherms, surface charge effect, and surface modification, we suggested that the formation of a bridged bidentate complex between aluminum ions of α-Al2O3 and two oxygen atoms of a sulfonic group induced the adsorption of NC onto α-Al2O3.

Listeria monocytogenes Serotype 1/2b and 4b Isolates from Human Clinical Cases and Foods Show Differences in Tolerance to Refrigeration and Salt Stress

Control of Listeria monocytogenes in food processing facilities is a difficult issue because of the ability of this microorganism to form biofilms and adapt to adverse environmental conditions. Survival at high concentrations of sodium chloride and growth at refrigeration temperatures are two other important characteristics of L. monocytogenes isolates. The aim of this study was to compare the growth characteristics under stress conditions at different temperatures of L. monocytogenes serotypes responsible for the majority of clinical cases from different sources. Twenty-two L. monocytogenes isolates, 12 from clinical cases (8 serotype 4b and 4 serotype 1/2a) and 10 from food (6 serotype 4b and 4 serotype 1/2a), and an L. monocytogenes Scott A (serotype 4b) reference strain were analyzed for the ability to grow in brain heart infusion broth plus 1.9 M NaCl (11%) at 4, 10, and 25°C for 73, 42, and 15 days, respectively. The majority of L. monocytogenes strains was viable or even grew at 4°C and under the high osmotic conditions usually used to control pathogens in the food industry. At 10°C, most strains could adapt and grow; however, no significant difference (P > 0.05) was found for lag-phase duration, maximum growth rate, and maximum cell density. At 25°C, all strains were able to grow, and populations increased by up 5 log CFU/ml. Clinical strains had a significantly longer lag phase and lower maximum cell density (P < 0.05) than did food strains. Regarding virulence potential, no significant differences in hemolytic activity were found among serotypes; however, serotype 4b strains were more invasive in Caco-2 cells than were serotype 1/2a strains (P < 0.05). The global tendency of decreasing NaCl concentrations in processed foods for health reasons may facilitate L. monocytogenes survival and growth in these products. Therefore, food companies must consider additional microbial growth barriers to assure product safety.

Salt-Free Dyeing of Cotton Woven Fabric with Reactive Dyes in Triton X-100 Reverse Micellar Media

The nonionic reverse micelles used for dyeing cotton fiber were prepared with a non-ionic surfactant Triton X-100 (TX-100) by injecting small amount of reactive dye aqueous solution. The percentage of dye bath exhaustion in TX-100 reverse micelles and in bulk water was carried out and compared, respectively. The effect of inorganic salt was also discussed. The results indicated that the dyeing properties of the reactive dyes on cotton fabric increased with decreasing NaCl concentration and increasing initial dye concentration in TX-100 reverse micelle. The percentage of dye bath exhaustion obtained in reverse micelles was higher than that in bulk water.

Physicochemical and sensory characterization of Cheddar cheese with variable NaCl levels and equal moisture content

The present study investigated the effect of salt (NaCl) on the flavor and texture of Cheddar cheese with the particular aim to elucidate consequences of, and strategies for, reducing the salt concentration. Descriptive sensory analysis and physicochemical mapping of 9-mo-old Cheddar cheeses containing 0.9, 1.3, 1.7, and 2.3% salt and an equal level of moisture (37.6±0.1%) were undertaken. Moisture regulation during manufacture resulted in slightly higher calcium retention (158 to 169mmol/kg) with decreasing NaCl concentration. Lactose was depleted only at 0.9 and 1.3% salt, resulting in concomitantly higher levels of lactate. Lower levels of casein components and free amino acids were observed with decreasing NaCl concentration, whereas levels of pH 4.6-soluble peptides were higher. Key taste-active compounds, including small hydrophobic peptides, lactose, lactate, and free amino acids, covaried positively with bitter, sweet, sour, and umami flavor intensities, respectively. An additional direct effect of salt due to taste–taste enhancement and suppression was noted. Sensory flavor profiles spanned a principal component dimension of palatability projecting true flavor compensation of salt into the space between cheeses containing 1.7 and 2.3% salt. This space was characterized by salt, umami, sweet, and a range of sapid flavors, and was contrasted by bitter and other off-flavors. Rheological and sensory measurements of texture were highly correlated. Cheeses made with 2.3% salt had a longer and slightly softer texture than cheeses containing 0.9, 1.3, and 1.7% salt, which all shared similar textural properties. Moisture regulation contributed to restoring the textural properties upon a 50% reduction in salt, but other factors were also important. On the other hand, significant flavor deterioration occurred inevitably. We discuss the potential of engineering a favorable basic taste profile to restore full palatability of Cheddar with a 50% reduction in salt.

Electrostatic Charge Measurement and Charge Neutralization of Fine Aerosol Particles during the Generation Process

AbstractAn aerosol charge analyzer has been constructed to measure the charge distribution of NaCl particles generated in the laboratory. A radioactive electrostatic charge neutralizer utilizing Po‐210 was used to neutralize the electrostatic charge of the particles. The atomization technique was used to generate NaCl particles with diameters of 0.2 to 0.8 μm, while the evaporation and condensation method was adopted to generate particles of 0.01 to 0.2 μm in diameter. The experimental data demonstrates that the absolute average particle charge depends on the particle diameter, and is higher than that calculated by the Boltzmann charge equilibrium for particles within the range of 0.2 to 0.8 μm. The charge increases with decreasing NaCl concentration. When these particles are neutralized using the Po‐210 neutralizer, it is found that the electrostatic charge reaches the Boltzmann charge equilibrium. For 0.01 to 0.2 μm NaCl particles generated using the evaporation and condensation method, test results show that the absolute average particle charge is higher than that calculated by the Boltzmann charge equilibrium for particles larger than 0.03 to 0.05 μm in diameter, while it is lower than that predicted by the Fuchs theory [1], for particles smaller than 0.03 to 0.05 μm. However, after charge neutralization, particles with diameter above 0.05 μm reach the Boltzmann charge equilibrium condition, and the charges for particles with diameters of 0.010 to 0.05 μm, agree well with Fuchs' theory.

Investigating the binding interaction of azur A with hyaluronic acid via spectrophotometry and its analytical application

The interaction between azur A (AA) and hyaluronic acid (HA) at AA concentrations from 3.430 x 10(-5) to 8.575 x 10(-5) M and sodium chloride concentrations from 0 to 0.01 M was investigated spectrophotometrically at 620 nm at temperatures from 0 to 50 degrees C. AA was shown to be a useful spectroscopic probe for detecting carboxyl groups in HA macromolecules. The interaction between AA and HA was temperature sensitive and little AA-HA interaction was observed at temperatures higher than 30 degrees C. The interaction of HA with AA was seen to be electrostatic in nature. The maximum binding number decreased with decreasing NaCl concentration, and the absorbance sensitivity decreased with increasing NaCl concentration in aqueous solution. Self-interference from the AA in the AA-HA interaction caused an overestimate of the molar mass of hyaluronic acid. An improved method was proposed to estimate the molar mass of HA, and a molar mass of 1.219 x 10(6) Da was obtained with this improved method for HA.

H5-HT(1B) receptor-mediated constitutive Galphai3-protein activation in stably transfected Chinese hamster ovary cells: an antibody capture assay reveals protean efficacy of 5-HT.

1. Serotonin 5-HT(1B) receptors couple to G-proteins of the Gi/o family. However, their activation of specific G-protein subtypes is poorly characterised. Using an innovative antibody capture/guanosine-5'-0-(3-[(35)S]thio)-triphosphate ([(35)S]GTPgammaS) binding strategy, we characterised Galpha(i3) subunit activation by h5-HT(1B) receptors stably expressed in Chinese hamster ovary (CHO) cells. 2. The agonists, 5-HT, alniditan and BMS181,101, stimulated Galpha(i3), whereas methiothepin and SB224,289 behaved as inverse agonists. The selective 5-HT(1B) receptor ligand, S18127, modestly stimulated Galpha(i3) and reversed the actions of both 5-HT and methiothepin. S18127 (1 micro M) also produced parallel, dextral shifts of the 5-HT and methiothepin isotherms. 3. Isotopic dilution experiments ([(35)S]GTPgammaS versus GTPgammaS) revealed high-affinity [(35)S]GTPgammaS binding to Galpha(i3) subunits in the absence of receptor ligands indicating constitutive activity. High-affinity [(35)S]GTPgammaS binding was increased 2.8-fold by 5-HT with an increase in the affinity of GTPgammaS for Galpha(i3) subunits. In contrast, methiothepin halved the number of high-affinity binding sites and decreased their affinity. 4. h5-HT(1B) receptor-mediated Galpha(i3) subunit activation was dependent on the concentration of NaCl. At 300 mM, 5-HT stimulated [(35)S]GTPgammaS binding, basal Galpha(i3) activation was low and methiothepin was inactive. In contrast, at 10 mM NaCl, basal activity was enhanced and the inverse agonist activity of methiothepin was accentuated. Under these conditions, 5-HT decreased Galpha(i3) activation. 5. In conclusion, at h5-HT(1B) receptors expressed in CHO cells: (i) inverse agonist induced inhibition of Galpha(i3), and its reversal by S18127, reveals constitutive activation of this Galpha subunit; (ii) constitutive Galpha(i3) activation can be quantified by isotopic dilution [(35)S]GTPgammaS binding and (iii) decreasing NaCl concentrations enhances Galpha(i3) activation and leads to protean agonist properties of 5-HT: that is a switch to inhibition of Galpha(i3).

Lontophoretic delivery of apomorphine in vitro: physicochemic considerations.

To examine the mechanisms of transdermal iontophoretic delivery of apomorphine. Anodal iontophoresis of R-apomorphine across human stratum corneum was determined in vitro. The effects on the flux of the following parameters were studied: stability of drug, pH of donor solution, concentration of NaCl, and type of Na+ co-ions. Ascorbic acid was effective to prevent apomorphine degradation. The iontophoretic transport of apomorphine was strongly influenced by the pH of the donor formulation. Increasing the pH from 3 to 6 resulted in an increase in the iontophoretic apomorphine flux from 27.9+/-4.4 nmol/cm2*h to 78.2+/-6.9 nmol/cm2*h. Upon decreasing NaCl concentration from 8 to 2 g/L, the iontophoretic flux was not significantly changed. Replacing NaCl in the donor formulation by tetraethylammonium chloride or tetrabutylammonium chloride resulted in 1.3 fold greater steady-state flux. For optimized apomorphine iontophoretic delivery, a constant pH of the donor formulation is of great importance. The results suggest that although flux enhancement during iontophoresis is largely due to the electrical potential gradient, secondary effects, such as convective flow and electroosmosis may also contribute.

Solvent extraction separation of zinc and cadmium from nickel and cobalt using Aliquat 336, a strong base anion exchanger, in the chloride and thiocyanate forms

Zinc and cadmium solvent extraction separation from cobalt and nickel was studied using 30% Aliquat 336 in either the chloride (R 4NCl) or thiocyanate (R 4NSCN) forms, and in a mixed aromatic-aliphatic diluent. With NaCl solutions good separation was achieved using R 4NCl. Separation improved with decreasing NaCl concentration, but was still effective with 200 g/L NaCl. Zinc and cadmium loaded principally as [MCl 4] 2− complexes. The maximum loading was 18 g/L for zinc and 28 g/L for cadmium. There was a small selectivity for cadmium over zinc. The mole ratio of organic reagent to metal (R 4N:M) was about 2. Separation with R 4NSCN was studied with NaCl, NaNO 3 and Na 2SO 4 solutions. Zinc extraction was favored over cadmium in each case and cadmium extraction decreased markedly in the order NaCl>NaNO 3>Na 2SO 4. Maximum zinc loadings were, respectively, 20 g/L, 9 g/L and 6 g/L. The selectivity for zinc over cadmium was rationalized on the basis of the different types of thiocyanate complexes formed by zinc and cadmium. From chloride solution the loaded complexes contained chloride and thiocyanate. The R 4N:M ratio was about 2. From nitrate solution, [M(SCN) 4] 2− species loaded. With chloride or nitrate medium, separation of zinc from cobalt and nickel was good, but separation of cadmium from cobalt was only moderate at best. Thiocyanate losses from the organic phase in these two systems were generally low with zinc loading (<1%), but high for cadmium loading. In the case of sulfate medium, zinc loaded predominantly. However, nickel loaded up to 0.14 g/L even at the highest zinc loading. Ammonia stripping of zinc and cadmium loaded R 4NCl was also studied and was found to be effective.

Red blood cell osmotic fragility confidence intervals: a definition by application of a mathematical model.

The red blood cell osmotic fragility test is based on the measure of the resistance of red blood cells to lysis as a function of decreasing NaCl concentration. Up to now, several methods have been used for recording these data, but for the first time, the human red blood cell osmotic fragility confidence interval using the Orcutt mathematical model was determined. The absorbance of the hemoglobin measured at 540 nm, released by the red blood cells of 40 healthy adult individuals, was fitted to the equation Absorbance=p3 erfc ([NaCl] - p1/p2); p3 measures one half the absorbance produced by maximum red blood cell hemolysis, p1 is the [NaCl] producing 50% red blood cell hemolysis, and p2 is the dispersion in [NaCl] producing red blood cell hemolysis. Confidence intervals (mean+/-SD) for the three parameters were as follows: p1=4.2718+/-0.1848; p2=0.1947+/-0.0391, and p3=0.5568+0.0426. The usefulness of this osmotic fragility data analysis method using two pathological samples (beta-thalassemia minor and hereditary spherocytosis) was demonstrated. Parameters of the fitted data were compared with those obtained by the conventional recording method of Beutler.

Horseradish peroxidase binding to intestinal brush-border membranes of Cyprinus carpio. Identification of a putative receptor.

Morphologic studies have shown that the classic endocytosis tracer horseradish peroxidase (HRP) is actively internalized by vesicular transport in the carp intestine, suggesting the existence of specific binding sites in the apical membrane of enterocytes. The aim of the present study was to develop an in vitro binding assay using isolated carp intestinal brush-border membranes (BBM) to demonstrate and characterize these specific HRP binding sites. The results obtained show that HRP binding to BBM exhibits a saturable mode and high affinity (K(d) = 22 nM). In addition, HRP binding sites are highly enriched in BBM compared to basolateral membranes. On the other hand, HRP interaction with these sites is apparently of an ionic character because binding increased concomitantly with decreasing NaCl concentrations in the assay, reaching a maximum in the absence of NaCl. Other proteins that are also internalized in carp intestine did not significantly inhibit HRP binding to BBM. A lectin-type of interaction was discarded because neither manan nor ovoalbumin inhibited HRP binding. Proteinase K treatment of BBM reduced HRP binding by 70%, suggesting a proteic nature for this binding site. Finally, ligand blotting assays showed that HRP binds specifically to a 15.3-kDa protein. Taken together, these results are consistent with the existence of a functional receptor for HRP in carp intestinal mucosa that could mediate its internalization.

Control of the plant pathogenic fungus Macrophomina phaseolina in mung bean by a microalgal extract

SUMMARYAn anti‐fungal antibiotic was characterized from an extract of Calothrix sp. TISTR 8906 with respect to an inhibition effect on plant pathogenic fungi. Optimal medium for anti‐fungal compound production was modified from nitrogen‐free BGA medium by the addition of NaN03 at the concentration of 1.5gL‐1, increasing K2HP04 concentration to 1.5 g L‐1 and decreasing NaCl concentration to 0.03 g L‐1 with an initial pH of 7.0. Algal growth, anti‐fungal activity and anti‐fungal compound production could be increased 2.6‐fold, four‐fold and 10‐fold, respectively. Crude algal extract formulated with surfactant applied to Macrophomina phaseolina at a concentration of 250 μg seed‐1 showed the same efficiency at inhibition as the commercial fungicide, mancozeb, at the recommended dose of 200 μg seed‐1, both in laboratory and pot experiments.

Stress corrosion crack propagation in AerMet 100

Fracture mechanics tests were carried out for AerMet 100 in distilled water and NaCl (3.5 and 35 gl−1). The initiation period at higher values of the stress intensity factor indicated that load application in the stress corrosion cracking (SCC) environment is a necessary but not sufficient factor for SCC and that time is needed for some other factor (e.g., the local hydrogen concentration) to reach an appropriate value. The threshold stress intensity factor, KISSC, was found to increase with decreasing NaCl concentration. The plateau stress corrosion crack velocity was 2 × 10−8 m s−1 for NaCl (3.5 and 35 gl−1). The fracture mode was transgranular with small areas of an intergranular nature.