Effect of iodonium salt and chitosan on the physical and antibacterial properties of experimental infiltrants

Abstract Resinous infiltrants are indicated in the treatment of incipient carious lesions, and further development of these materials may contribute to greater control of these lesions. The aim of this study was to analyze the physical and antibacterial properties of experimental infiltrants containing iodonium salt and chitosan. Nine experimental infiltrants were formulated by varying the concentration of the diphenyliodonium salt (DPI) at 0, 0.5 and 1 mol%; and chitosan at 0, 0.12 and 0.25 g%. The infiltrants contained the monomeric base of triethylene glycol dimethacrylate and bisphenol-A dimethacrylate ethoxylate in a 75 and 25% proportion by weight, respectively; 0.5 mol% camphorquinone and 1 mol% ethyl 4-dimethylaminobenzoate. The degree of conversion was evaluated using Fourier transformer infrared spectroscopy, and the flexural strength and elastic modulus using the three-point bending test. Sorption and solubility in water, and antibacterial analysis (minimum inhibitory concentration and minimum bactericidal concentration) were also analyzed. Data was analyzed statistically by two-way ANOVA and Tukey's test (p<0.05), with the exception of the antibacterial test, which was evaluated by visual inspection. In general, the infiltrant group containing 0.5% DPI and 0.12% chitosan showed high values of degree of conversion, higher values of elastic modulus and flexural strength, and lower sorption values in relation to the other groups. Antibacterial activity was observed in all the groups with DPI, regardless of the concentration of chitosan. The addition of DPI and chitosan to experimental infiltrants represents a valid option for producing infiltrants with desirable physical and antibacterial characteristics.

Purification of inulinases by changing the ionic strength of the medium and precipitation with alcohols

ABSTRACT The present study evaluated the purification of inulinase by changing the ionic strength of the medium by addition of NaCl and CaCl2 followed by precipitation with n-propyl alcohol or iso-propyl alcohol. The effects of the concentration of alcohols and the rate of addition of alcohols in the crude extract on the purification yield and purification factor were evaluated. Precipitation caused an activation of enzyme and allowed purification factors up to 2.4-fold for both alcohols. The purification factor was affected positively by the modification of the ionic strength of the medium to 0.5 mol.L-1 NaCl before precipitation with the alcohol (n-propyl or iso-propyl). A purification factor of 4.8-fold and an enzyme yield of 78.1 % could be achieved by the addition of 0.5 mol.L-1 of NaCl to the crude extract, followed by the precipitation with 50 % (v/v) of n-propyl alcohol, added at a flow rate of 19.9 mL/min.

Comparative study between marsh salt and salines salt from physical and chemical aspect

This study was conducted to evaluate the hygienic quality of the salt obtained from marshes [El-sayahat] and that from salines .The salt produced from saline was much better than that from marshes for the following reasons. March salt had inferior taste and colour quality compared with saline salt. The sodium chloride content in marsh salt reached up to 73%, while that from salines reached up to 97%. The iron content in march salt reached up to 2.270 ppm while that from salines reached up to 0.004 ppm. The copper content reached up to 1.385 ppm in salt produced from marsh while it was 0.292 ppm from salines. The cadmium content in marsh salt reached up to 0.135 ppm while it was 0.001ppm in salts from salines. The lead content in marsh salt reached up to 1.200 ppm while it was 0.001 in salt from salines. Sulfur pesticides residues in marshes salt ranged from 0.41 to 3.3 mg/kg. The authors recommended that mass media should educate the public about the deleterious effect of salt produced from marches on human health and legal actions have to be under taken against those who still produce salt from marshes

Evaluation of change in water quality with strong acid exchanger effluent conductivity.

Koradi Thermal Power Station requires 1-1.2 lakh m3 of water per day and pond No. 3 is the source of water supply of Koradi Thermal Power Station. This Pond No. 3 is being replenished by Pench Canal water, but water undergoes significant changes in quality after entering Pond No. 3 and hence this aspect may be crucial for raw water intake at Water Treatment Plant Stg-II of Koradi Thermal Power Station. Therefore, an attempt has been made to evaluate the change in water quality on the basis of Strong Acid Cation Exchanger Effluent Conductivity and its impact on demineralised water treatment plant.

Improved method for estimation of inorganic phosphate: implications for its application in enzyme assays.

The conventional method of Fiske and Subba Row for the estimation of inorganic phosphate (Pi) is although rapid, but suffers from the disadvantage that the color is unstable and hence the optical density (OD) measurements have to be carried out within a short time span of 8-12 min. This poses a restriction on the number of samples, which can be handled in a batch. Although, modified procedures involving use of alternate reducing agents/or increasing the concentration of H2SO4 in conventional method have been subsequently developed, but the problem of color stability could not be solved. In addition, the use of higher concentrations H2SO4 has rendered the methods unsuitable in enzyme assays, especially if the acid labile phosphate containing substrates have been used. In the present study, attempts have been made to suitably modify the method to improve the stability of the color and sensitivity and also for its applicability in enzyme assays, especially when acid labile phosphate containing substrates such as ATP is used. We used the higher concentrations (0.625, 0.8 and 1.0 N) of H2SO4 rather than 0.5 N used in the conventional assay procedures. Under these conditions, the reagent blanks do not develop color for up to 24 h, whereas the intensity of the molybdenum blue color in the standard and/or experimental tubes increased with time reaching optimum value at 24 h. Simultaneously, the absorption maximum shifts from 660 nm to 820 nm. The highest concentration of H2SO4 (1.0 N) is found to be the most effective in the process of color development. The sensitivity of the method is from 1.7 to 2.1 times higher, as compared to the conventional Fiske and Subba Row method for the measurements carried out at the end of 15 min at 820 nm and with the highest concentration of H2SO4 (1.0 N); the sensitivity increased 4.8-fold at the end of 24 h. Presence of glucose and sucrose (1-10 mM), NaCl and KCI (5-100 mM), MgCl2 (1-10 mM) and BSA (10 to 500 microg per assay tube) do not interfere either with color development or with OD measurements. The extent of ATP hydrolysis is 1.6 to 3.4% for up to 1 hi, depending upon the concentration of H2SO4 used. Only negligible hydrolysis of G6P is observed under these conditions. These results suggest that the presently modified method is suitable for Pi analysis in the enzyme assays, in the presence of labile phosphate containing substrates.

Iodine content of various salt samples sold in Mangalore--a coastal city with endemic goitre.

OBJECTIVE: Iodine deficiency disorders continue to be high despite ban on sale of non-iodised salt. In order to assess the effectiveness of salt iodisation programme, a study was undertaken to assess the iodine content of salt samples sold in Mangalore. MATERIAL AND METHODS: One hundred salt samples were randomly collected from shops in Mangalore and iodine content measured using MBI iodine testing kits. RESULTS: Only 39 samples had adequate iodine of 15 ppm or more. There was a statistically significant difference in the salt samples with adequate content in rural versus urban areas (46.6% and 27.5%, respectively, with p < 0.05). Branded samples had significantly higher iodine content than non-branded salt (p < 0.05). Salt sold at Rs.2/- per kg had significantly lower iodine content than the salt sold at Rs.3-4/- per kg (p < 0.01). CONCLUSION: Salt iodisation programme is poorly implemented in Mangalore probably due to improper iodisation, inadequate storage, hot and humid weather conditions and lack of public awareness. Public education and education of shop owners regarding their role in prevention of iodine deficiency disorders may be of value in this direction.

Effects of salt and denaturant on structure of the amino terminal alpha-helical segment of an antibacterial peptide dermaseptin and its binding to model membranes.

The amino terminal 1-18 domain of dermaseptin s is an important determinant of its structure as well as the antibacterial activity. A thorough investigation on the structure of the 18-residue peptide (D18) and its binding to model membranes in presence of salt and denaturant guanidinium chloride has been carried out. In presence of salt, there is an increase in the fraction of peptide molecules in helical conformation. In presence of the denaturant, D18 is unordered, but addition of the structure-promoting solvent trifluoroethanol results in a transition to the helical conformation. In presence of denaturant, the peptide is unordered, but binding to lipid vesicles is not abolished. Investigation of model membrane permeabilizing ability of the peptide in solutions containing various proportions of sodium chloride and guanidinium chloride indicates that vesicle permeabilization parallels extent of binding. The peptide thus binds to lipid vesicles in an unfolded state. Since the peptide has propensity to fold into a helical conformation, lipid induced transition to a helical structure occurs, followed by membrane permeabilization as a result of pore formation.

Postulated effects on water structure of some salts and protein denaturants as inferred from measurements of viscosity B coefficients: example of HbS polymerization.

Viscosity measurements have been performed on aqueous solutions of some solutes commonly used in biochemical practice, with a view to determine the B coefficients and their temperature dependence. The temperature dependence measured for some anions leads to a ranking of the latter in an order similar to that reported earlier from entropy data for their postulated efficiency in disrupting "water structure". The well known dependence of denaturing power of guanidinium salts on the anions is shown to be related to the temperature dependence of B coefficients. Urea and formamide do not appear from this criterion to be significantly "structure-breaking"; alkyl-substituted derivatives of urea and formamide, on the other hand, possess significant "structure-forming" properties. The results are of interest in relation to the known effects of salts and other solutes on the stability of protein structures in respect of denaturation, subunit dissociation or self assembly. A typical application is illustrated by studying the effect of two anions, namely nitrate and sulphate, on the polymerization of sickle cell hemoglobin (HbS). Nitrate, which is believed to disrupt water structure, acts as an inhibitor of HbS polymerization which, on the contrary, is favoured by sulphate, a postulated structure- former.

Iodine nutritional status of the school-age children in South Tripura, North East India.

To evaluate the iodine nutritional status, the thyroids of 3,577 school-age children of both sexes are examined clinically by palpation for goiter prevalence, 345 urine samples are analysed by dry ashing to determine the urinary iodine excretion pattern and 121 edible salt samples collected from house hold are analysed by iodometric titration to monitor the iodinatien achieved through salt from 6 representative areas of South Tripura in goiter endemic North East India. Endemic goiter is found prevalent in all the study areas though its occurrence varies from 13.95% to 30.96%, indicating that clinically mild to severe degree of iodine deficiency prevails in the region. But the pattern of median urinary iodine level of the studied population shows that there is no biochemical iodine deficiency. In 66.94% salt samples had iodine content less than the recommended level of 15 ppm. As per the classification recommended by WHO/UNICEF/ICCIDD, South Tripura falls into goiter endemic by clinical criteria and no endemicity by biochemical criteria. However, iodine deficiency disorders (IDD) continue to be prevalent in the region.

Thermodynamics of water-lipid interaction in presence and absence of salts.

Extents of hydration of different lipids such as cholesterol, lecithin, lysolecithin, gangliosides, hydroxy cerebrosides, sphingomyelin, Dalda (hydrogenated fat), coconut oil and sunflower oil in the presence and absence of some inorganic electrolytes, sucrose and urea have been studied using the isopiestic vapour pressure technique. Except triglycerides, the shape of the water vapour adsorption isotherms for other lipids are in agreement with type II or type III BET isotherms respectively. The overall shape of each curve for triglycerides does not agree with any of the shapes of five types of BET isotherms. At water activity (1) approaching unity, maximum number of moles of water bound (delta n1zero) per mole of cholesterol are 1.6 and 2.6 at 28 degrees C and 37 degrees C, respectively. Values of delta n1zero at 23 degrees C stand in the following order: Ganglioside > lysolecithin > sphingomyelin > hydroxy cerebrosides. For triglycerides n1 increases with increase of a1 and reaches maximum in between 0.95 to 0.98 beyond which it sharply decreases to zero as a1 approaches unity. Standard free energy changes (delta Gzero) and enthalpy changes (delta Hzero) for cholesterol and lysolecithin have been evaluated from the experimental data. The excess hydration of cholesterol in the presence of several inorganic salts, urea and sucrose have been estimated from isopiestic experiments and free energies of excess hydration have been evaluated.

Production of extracellular protease by Streptomyces fradiae.

A new strain of Streptomyces fradiae, isolated and identified in our laboratory, was found to be a potential producer of protease enzyme. An enzyme yield of 285 P.U./ml. was obtained prior to optimization in a synthetic medium containing potato starch, potassium nitrate and trace salts by shake flask method. The carbon and nitrogen compounds play prominent role in the protease production. The maximum enzyme yield of 930 P.U./ml. (about 3-fold increase) was obtained with all optimum parameters such as pH. 7.0, with 3% jowar starch, 0.5% tryptone, 28 degrees C incubation temperature, with 1:20 medium to flask volume ratio and with 48 hrs. inoculum.

Thermodynamics of binding water and solute to powdered long-chain salts of fatty acids.

Hydration of powdered fatty acids and their salts has been studied both in presence and absence of neutral salts, sucrose and urea using the isopiestic vapour pressure technique. Moles of water vapour adsorbed per mole or kg of soaps like sodium palmitate, sodium stearate, sodium myristate and sodium laurate have been measured in presence and absence of salts and compared with that of detergents (SDS, CTAB, DTAB and MTAB). For each case of positive excess adsorption of water vapour and negative excess adsorption of inorganic salts, urea and sucrose to different soaps, the standard free energy change (delta G degrees) per kg of substrate in bringing the bulk mole fraction from zero to unity have been calculated using an appropriate thermodynamic equation and the values so obtained have been compared critically.