Rational design of biocompatible IPNs hydrogels containing carboxymethyl starch and trimethyl chitosan chloride with high antibacterial activity

Cellulose - Antimicrobial hydrogels have enticed a major concern for repairing soft tissues, particularly prohibiting bacterial infections that are frequently accompanied by impaired wound healing....     

Development of an analytical method using microchip capillary electrophoresis for the measurement of fluorescein-labeled salivary components in response to exercise stress

We have developed an analytical method using microchip capillary electrophoresis (microchip CE) for the high-speed separation of fluorescein-labeled salivary components in response to exercise stress. Optimal separation was obtained using a borate buffer at pH 9.5 containing 10 mM beta-cyclodextrin and 1.0% (w/v) methylcellulose. To minimize individual differences in human saliva, such as viscosity, conductivity, and contaminants, the concentration of methylcellulose in the analytical conditions played a key factor. The optimized separation conditions produced identical electropherograms successfully despite of the use of different microchips made from quartz glass or poly-methylmethacrylate (PMMA). In addition, a practical application of bicycle ergometer stress was performed. Some components in human saliva showed a marked decrease after exercise stress.     

Elution mechanism of polypeptides in reversed-phase liquid chromatography based on the critical threshold of organic solvent to induce abrupt change in adsorption capacity to the column packing

Adsorption capacity of polypeptides to the column packing in a solution containing multiple organic solvents was found to be expressed by means of an fn value, which is the sum of the ratios of the content of each organic solvent in the solution to the critical content of each organic solvent to cause abrupt change in the adsorption capacity, and to change abruptly at the point where the fn value becomes 1. Additionally, our results indicate that each polypeptide is eluted by the eluent containing a specific organic solvent content regardless of gradient elution rate in reversed-phase liquid chromatography, and that total organic solvent content in the eluent containing polypeptides is equal to the critical content. Considering the power law relationship between the retention times and the gradient elution rates, our results suggest that the elution of each polypeptide in reversed-phase liquid chromatography is mainly controlled by abrupt change in the adsorption capacity induced by change in the organic solvent content of the eluent during a gradient elution process, and that the abrupt change repeats across the critical threshold while a polypeptide moves through the column, and as a result, each polypeptide is concentrated in the eluent with the critical threshold.     

Validation of real-time PCR analyses for line-specific quantitation of genetically modified maize and soybean using new reference molecules

Novel analytical methods based on real-time quantitative polymerase chain reactions by use of new reference molecules were validated in interlaboratory studies for the quantitation of genetically modified (GM) maize and soy. More than 13 laboratories from Japan, Korea, and the United States participated in the studies. The interlaboratory studies included 2 separate stages: (1) measurement tests of coefficient values, the ratio of recombinant DNA (r-DNA) sequence, and endogenous DNA sequence in the seeds of GM maize and GM soy; and (2) blind tests with 6 pairs of maize and soy samples, including different levels of GM maize or GM soy. Test results showed that the methods are applicable to the specific quantitation of the 5 lines of GM maize and one line of GM soy. After statistical treatment to remove outliers, the repeatability and reproducibility of these methods at a level of 5.0% were <13.7 and 15.9%, respectively. The quantitation limits of the methods were 0.50% for Bt11, T25, and MON810, and 0.10% for GA21, Event176, and Roundup Ready soy. The results of blind tests showed that the numerical information obtained from these methods will contribute to practical analyses for labeling systems of GM crops.     

Determination of psilocybin in hallucinogenic mushrooms by reversed-phase liquid chromatography with fluorescence detection

The determination of psilocybin was carried out by reversed-phase liquid chromatography (HPLC) with fluorescence (FL) detection. Psilocybin was labeled with 5-dimethylaminonaphthalene-1-[N-(2-aminoethyl)]sulfonamide (DNS-ED) at 60 °C for 4 h in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) as the activation reagent. The resulting derivative was separated on a Mightysil RP-18 GP column (150 mm × 4.6 mm, i.d. 3 μm) with the mixture of 50 mM ammonium acetate (AcONH₄) and CH₃CN, and detected at 539 nm (excitation at 321 nm). The structure of the derivative was identified by HPLC-ESI-MS. A good linear relation of the calibration curve of psilocybin was observed under the proposed conditions for labeling, separation and detection. The quantification limit was 4.4 ng in 1 mg dried mushroom. The proposed procedure was successfully used for the determination of psilocybin in real samples. The contents of psilocybin in six magic mushrooms by the proposed HPLC-FL method were less than 20.0 ng in 1 mg dried samples.     

Gastric acidity-dependent bioavailability of commercial sustained release preparations of indomethacin, evaluated by gastric acidity-controlled beagle dogs

The relationship between gastric acidity and the bioavailability of two kinds of sustained-release indomethacin (IM) formulations was investigated in gastric acidity-controlled beagle dogs, and compared with that of rapid-release IM formulations. All test dosage forms were more rapidly dissolved in simulated intestinal fluid than in simulated gastric fluid. Gastric acidity did not affect the bioavailability of IM from the rapid-release formulation. However, the bioavailability of IM from the two kinds of sustained-release formulations were markedly influenced by gastric acidity. The rates of IM bioavailability from both of the sustained-release formulations were faster under low acidity conditions than under high acidity conditions (p less than 0.01). In addition, Tmax and mean residence time (MRT) were approximately the same for the rapid-release and sustained-release formulations under low acidity conditions. These results suggest that the IM sustained-release formulations showed a rapid-release profile under low acidity conditions.     

Unique sugar metabolism and novel enzymes of hyperthermophilic archaea

Hyperthermophiles are a group of microorganisms that have their optimum growth temperature above 80 degrees C. More than 60 species of the hyperthermophiles have been isolated from marine and continental volcanic environments. Most hyperthermophiles belong to Archaea, the third domain of life, and are considered to be the most ancient of all extant life forms. Recent studies have revealed the presence of unusual sugar metabolic processes in hyperthermophilic archaea, for example, a modified Embden-Meyerhof pathway, that has so far not been observed in bacteria and eucarya. Several novel enzymes, such as ADP-dependent glucokinase, ADP-dependent phosphofructokinase, glyceraldehyde-3-phosphate ferredoxin oxidoreductase, phosphoenolpyruvate synthase, pyruvate : ferredoxin oxidoreductase, and ADP-forming acetyl-CoA synthetase, have been found to be involved in a modified Embden-Meyerhof pathway of the hyperthermophilic archaeon Pyrococcus furiosus. In addition, a unique mode of ATP regeneration has been postulated to exist in the pathway of P. furiosus. The metabolic design observed in this microorganism might reflect the situation at an early stage of evolution.     

A new methodology for the oxidation of sulfides with Fe(III) catalysts

A variety of sulfides were converted to the corresponding sulfoxide derivatives with 70% t‐BuOOH (water) as the oxidant in the presence of catalytic quantity of Fe₂(SO₄)₃. The method described has a wide range of applications, involves simple work‐up, exhibits chemoselectivity/enantioselectivity and proceeds under mild reaction conditions. The resulting products are obtained in good yield within a reasonable time. Copyright © 2012 John Wiley & Sons, Ltd.