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Binding of tetracationic porphyrin (TMPyP4+) to poly(rA) has been studied in neutral buffered solution of low ionic strength in a wide range of molar phosphate-to-dye ratios (P/D) using absorption ...

The qualitative characteristics of meat products are closely related to the functionality of muscle proteins. Myofibrillar proteins (MPs), comprising approximately 50% of total muscle proteins, are generally considered to be insoluble in solutions of low ionic strength (0.2 M), requiring high concentrations of salt (0.3 M) for solubilization. These soluble proteins are the ones which determine many functional properties of meat products, including emulsification and thermal gelation. In order to increase the utilization of meat and meat products, many studies have investigated the solubilization of MPs in water or low ionic strength media and determining their functionality. However, there still remains a lack of systematic information on the functional properties of MPs solubilized in this manner. Hence, this review will explore some typical techniques that have been used. The main procedures used for their solubilization, the fundamental principles and their functionalities in water (low ionic strength medium) are comprehensively discussed. In addition, advantages and disadvantages of each technique are summarized. Finally, future considerations are presented to facilitate progress in this new area and to enable water soluble muscle MPs to be utilized as novel meat ingredients in the food industry.

Fast DNA detection remains of great interest in human genetics, medicine, and drug discovery. The detection of DNA hybridisation makes the screening of point mutations in potential cancer genes or DNA fingerprinting for phylogenesis purposes possible (S.W. Yeung, T.M.H. Lee, H. Cai, and I.M. Hsing, A DNA biochip for on-the-spot multiplexed pathogen identification, Nucleic Acids Research 34 (2006), p. e118; P. Liepold, H. Wieder, H. Hillebrandt, A. Friebel, G. Hartwich, DNA-arrays with electrical detection: a label-free low cost technology for routine use in life sciences and diagnostics, Bioelectrochemistry, 67 (2005), pp. 143–150). The speed, cost and reliability of the hybridisation detection is of high importance. Electronic detection of hybridisation events using standard CMOS-fabricated devices such as Field Effect Transistors (FETs) promises fast, label-free and multiplexed read-out systems. Moreover, they hold the advantage of high-throughput and minimalisation, which makes them ideal for implement...

The growth of a cultivar of wheat (Triticum aestivum L.), “Atlas 66,” was studied under conditions of low background nutrient concentrations and a daily nutrient-addition rate controlled by a computer program. Different calcium (Ca) concentrations were supplied by a daily delivery stock solution and by a background nutrient solution. When Ca was supplied by a delivery solution, plant mass production increased as Ca concentrations increased, but the rate of plant growth was lower than the theoretical production. In addition, solution pH decreased and electrical conductivity (EC) increased over time. On the other hand, when Ca was supplied as a background solution, plant growth was similar to theoretical production at a Ca concentration ranging from 100 to 800 μM. In this range, solution pH increased, but solution EC remained stable over time. Calcium supply only by a delivery stock solution was found to be inadequate to support optimal growth of wheat plants. However an initial nutrient solution c...

A flow‐through, low ionic strength nutrient solution system was used in four experiments to establish elongation rates, time to maximum length of individual root hairs, and temporal changes in length in small populations of root hairs in a genotype from a population of cv ‘Tamar’ white clover (Trifolium repens L.) previously selected for long root hairs. Young root hairs showed pronounced pulsatile growth, with relative extension rates increasing four‐fold over the basal rate. In older hairs the amplitude and frequency of the pulsatile growth declined as hairs approached their full length. At the average root hair elongation rate over all hairs and experiments (3.3 mm h‐1) it would take 4.5 days for the longest root hair observed (363 μm) to reach its final length, and 2.4 days to reach the population mean root hair length of 190 μm. Re‐analysis of the data using a Bayesian technique gave an estimate of 2.0 days for root hairs to reach the population mean length. The results suggest that root tip...

We have studied structural changes in DNA/protein complexes using the CD spectroscopy, upon the interaction of HMG1-domains with calf thymus DNA at different ionic strengths. HMG1 protein isolated from calf thymus and recombinant HMG1-(A+B) protein were used. Recombinant protein HMG1-(A+B) represents a rat HMG1 lacking C-terminal acidic tail. At low ionic strength (15 mM NaCl) we observed similar behavior of both proteins upon interaction with DNA. Despite this, at higher ionic strength (150 mM NaCl) their interaction with DNA leads to a completely different structure of the complexes. In the case of HMG1-(A+B)/DNA complexes we observed the appearance of DNA fractions possessing very high optical activity. This could be a result of formation of the highly-ordered DNA structures modulated by the interaction with HMG1-domains. Thus the comparison studies of HMG1 and HMG1-(A+B) interaction with DNA show that negatively charged C-terminal tail of HMG1 modulates interaction of the protein with DNA. The striking difference of the behaviour of these two systems allows us to explain the functional role of multiple HMG1 domains in some regulatory and architectural proteins.

Probe spectrofluorimetry studies for ovalbumin (OVA) show an increase in surface hy-drophobicity at pressures > 400 MPa. Pressure treatment of mixtures of OVA+ dextran sulphate (DS) greatly reduces the surface hydrophobicity. Size exclusion chromatography data indicate that stronger protein-polysaccharide complex(es) are formed during treatment at low ionic strength and pH 6.5. Emulsions made with pressurized (600 MPa) OVA in the presence of polysaccharide at pH 6.2 and low ionic strength exhibit the improved emulsifying efficiency and stabilizing properties of the protein. Under pressure treatment at pH ≤ 6.5, OVA forms reversible electrostatic complex(es) and the strength of interaction is related to the charge density on the polysaccharide (DS > Ltarrageenan (t-CAR) > κ-carrageenan (κ-CAR)). Complexation of OVA with polysaccharide seems to protect the protein against loss of functionality from pressure-induced aggregation.

A simple computer model based on chemical equilibrium calculation for evaluating the aluminum speciation in surface waters of low ionic strength (I < 1 × 10−4 M) was presented in this paper. The speciations of aluminum obtained by this model have been compared with those obtained experimentally and the reasons for the observed differences have been discussed. This model has been applied to the estimation of aluminum speciation in practical surface waters sampling from areas of the United Kingdom, United States and People's Republic of China. Some valuable conclusions are obtained.

Gigaseals were obtained from enzymatically dissociated epithelial cells of Hydra vulgaris, and resting potentials were recorded in the whole‐cell configuration. These results were obtained in spite of hard difficulties of applying patch‐clamp techniques in the whole‐cell configuration to Hydra cells. These difficulties are principally inherent to the fact that Hydra lives in a low ionic strength medium. It will be now possible to apply patch‐clamp techniques to the study of Hydra extraocular photoreception.

The aluminium (Al) tolerance of white clover (Trifolium repens L.) lines that had either long or short root hair lengths were evaluated in low ionic strength (2.7 x 10‐3 M) solution culture. Absolute yield of the long root hair length plants was greater than the short root hair length plants at all Al rates by, on average, 34%. However, increasing root hair length had no significant (P

The first 2 years of monthly‐sampled physico‐chemical data from 77 river and stream sites in New Zealand's National River Water Quality Network are summarised. The data for the major ions, pH, dissolved oxygen, conductivity, clarity, temperature, and NO3‐N from the majority of sites are normally distributed. The data for flow, BOD5, turbidity, absorption coefficients, and total and dissolved nutrients (except for NO3‐N) from most sites are positively skewed. Combined data for all sites are compared with water quality standards and criteria, and “average” world freshwater concentrations. The vast majority of samples are well within accepted standards and criteria for a variety of river water uses and the waters can be classed as being of relatively low ionic strength.

Iron (III) oxide precipitated from Fe2(SO4)3 by NaOH was found to adsorb Hg (II) over the pH range from 3 to 10. Adsorption was not found to be affected by pH in the range from 4 to 10, but dropped off sharply between pH 4 and pH 3. Chloride additions at the 0.6M level inhibited adsorption of Hg (II) at neutral pH, but not above pH 10; Hg(OH)2 was found to be the adsorbed species. In solutions with low ionic strength the adsorption by Fe(OH)3 follows the form of the Freundlich isotherm in the neutral range; Hg (II) is adsorbed less strongly on Fe(OH)3 than on MnO2. The corresponding exponential Freundlich constants for Fe(OH)3 are: 293 for the coefficient and 0.76 for the exponent of the equilibrium concentration of Hg (II) in solution. This is far less than 1.9 × 1010 for the coefficient and 1.73 for the exponent of the equilibrium concentration of mercury in solution in the case of MnO2 adsorbent.

Between the fall of 1977 and December 1980, over 800 samples of precipitation were collected at 9 rural locations across Nova Scotia. Average pH was 4.61, and an average conductivity of 25 μS cm−1 confirmed the low ionic strength of rain and snow. Of all ions, chloride was the most abundant at 76 μeq L−1 (2.7 mg L−1). Oceanic origins were perceived as the source for chloride as well as for Na, Mg, 51 % of K, 21% of Ca, and 21% of SO4, and the sea collectively accounted for 66% of all ions inNova Scotian precipitation. In contrast, the dominating ions in New York, New Hampshire, Ontario and Norway were H+ and SO4. In Nova Scotia, chloride concentrations in rain (mg L−1) are a function of distance D (km) from the coast and may be described by the equation Cl [mg L−1] = 4.5D−0.42. It indicates that Cl concentrations are reduced by about 50% within 0.5 km of the coast, and 80% within 5 km. The continental North American chloride data examined are also consistent with the relationship. The shape of th...

Using drug concentration remaining at a given time as the criterion, a 24x3 factorial design has been employed to investigate the effects of temperature, light, media (aqueous or organic/aqueous), ionic strength and pH on the stability of doxorubicin hydrochloride. Following the application of first order kinetics, and assuming an additive model, the statistical significance of the factors and their interactions have been determined using analysis of variance (ANOVA) on the dependent variable ln(lnCo-InC). The results indicate that temperature, pH and media are the major factors responsible for the stability of drug. The two-way interaction between temperature and pH, and the three-way interaction between temperature, light and ionic strength are also significant. It is found that doxorubicin is more stable in non-aqueous media at low temperature and low pH values. A combination of darkness and low ionic strength is also conducive to its stability.

Potentiometric pH measurement in low ionic strength stream waters is difficult due to high system variability and low ionic activity. Imprecise measurement may result from equipment response in such waters and solution pH drift caused by gaseous exchange and temperature change. An acceptable method for field pH determination must utilize sensitive equipment and stringent measurement stability criteria to ensure accurate and reliable measurements. Four methods for in situ and streamside pH determination were used to collect data from three low-ionic strength streams. The methods are compared, using analysis of variance and subjective evaluation.

Specific conductance is shown to bear a well-defined, linear relationship to total dissolved solids for cold, low ionic strength streams. Unless the water temperature is constant it is necessary first to correct the conductivity data to 25°C. This temperature correction may be taken as linear, even below 4°C, but not necessarily to be 2% per °C as is commonly used in many instruments. The error incurred by assuming the latter figure for cold streams could be large (>5%). Values of specific conductance calculated using data for the limiting equivalent conductivities of the individual ions are shown to be poor estimates of the actual specific conductances even for these dilute waters. Relationships between total dissolved solids and specific conductance may be impaired by the changing proportions of ionic species of the samples. In general, however, an empirical straight line was found to provide a good fit.