Flexibility and strictness in functional replacement of domain III of cry insecticidal proteins from Bacillus thuringiensis

Cry1C, one of the lepidopteran-specific insecticidal proteins from Bacillus thuringiensis, exhibits potent cytotoxicity against Sf9, an insect cell line. Cry1Aa and Cry4A, which are lepidopteran- and dipteran-specific insecticidal proteins, respectively, show no cytotoxicity against Sf9. When domain III of Cry1C was replaced with that of Cry1Aa or Cry4A, the hybrid Cry1C protein retained the cytotoxicity. These results suggest that domain III of Cry1C is not crucial in determining the cytocidal specificity of Cry1C against Sf9.     

Development of a large volume zero boil-off liquid xenon storage system for muon rare decay experiment (MEG)

We have developed a new type of photon detector for an experiment aimed at searching for the lepton flavor violating decay μ⁺ → e⁺γ. In this experiment, a total of 900 L of liquid xenon is used in order for the scintillation detector to detect γ-rays with an extremely high sensitivity, where the liquid xenon is viewed by an array of 846 photomultipliers from all sides. The entire amount of xenon should be stored in certain storage systems before the start of the experiment, during detector maintenance in the period of accelerator shutdown, etc. We have developed a new liquid xenon storage system by employing the zero boil-off condition by using a pulse tube cryocooler. The details of system and its performance results are described in this article.     

Preparation of Fatty Acid Methyl Esters by Selective Methanolysis of Polar Glycerolipids

KOH in aqueous methanol catalyzes selective methanolysis of polar glycerolipids with O-ester-linked acyl residues, while triacylglycerols and sterol esters are inert in the solution. Based on these findings, a convenient and reliable method was developed for the preparation of fatty acid methyl esters (FAMEs) from polar glycerolipids in lipid mixtures without prior isolation. Methanolysis of polar glycerolipids was completed within 2.5 min by vortexing or 20 min by shaking with 0.7 M KOH/70% (v/v) methanol in the presence of hexane at 30 °C. The yields of FAMEs obtained by the present method were greater than 95%. The method was applied successfully to gas chromatographic analysis of the fatty acid compositions of polar glycerolipids in seed oil and blood. No obvious differences were found between the fatty acid compositions determined by the present method and those determined by conventional methods, including lipid extraction with chloroform/methanol followed by isolation of polar lipids by chromatography. The fatty acid composition of polar glycerolipids, including phospholipids, can be determined readily in many crude samples.     

Influence of shearing history on the rheological properties and processability of branched polymers. II. Optical properties of low-density polyethylene blown films

An investigation was performed to determine how optical properties of LDPE blown films changed when the material was subjected to extrusion shearing. In this study, shearing histories were given to the materials by designed extrusion shearing. Recognizable variations take place in haze and gloss of the blown film during the extrusion shearing. Such variations were expressed as a function of the processing index (PI), which was introduced in a preceding paper as a measure of the memory effect of shearing histories of LDPE. This means that the variations originate in a certain change in the cohesive state of the polymer molecules attributable to the shearing.     

Acyclic and incompletely cyclized triterpene alcohols in the seed oils of theaceae and Gramineae

The triterpene alcohol constituents of the non-saponifiable lipids of two Theaceae seed oils, sasanqua and camellia oils, and two Gramineae seed oils, wheat germ and rice bran oils, were investigated. This led to the isolation and characterization of one acyclic and eight incompletely cyclized triterpene alcohols. They are camelliol A, camelliol B, camelliol C, achilleol A, helianol, isohelianol, sasanquol, graminol A [(13R, 14R)-3,4-seco-25(10→9)abeo-8α,9β,10α-podioda-4,17,21-trien-3-ol], and (2Z,6Z,10Z,14E,18E)-farnesylfarnesol. Two other compounds isolated were characterized as (2Z,6Z,10E,14E)-geranylfarnesol, a sesterterpene alcohol, and phytol, a diterpene alcohol. Graminol A and (2Z,6Z,10E,14E)-geranylfarnesol are considered to be new natural products. Based on a paper presented at the symposium, “Chemistry, Biochemistry, and Function of Sterols,” AOCS Annual Meeting & Expo, Orlando, FL, May 1999.     

Paramyosin of the disc abalone Haliotis discus discus: Identification as a new allergen and cross-reactivity with tropomyosin

Tropomyosin, a 35–38 kDa myofibrillar protein, represents a major allergen in molluscs, as well as in crustaceans. Besides tropomyosin, a 100 kDa allergen was newly detected in the disc abalone Haliotis discus discus. The 100 kDa allergen was purified from the muscle of the disc abalone by salting-out and hydroxyapatite HPLC and identified as paramyosin based on the determined amino acid sequences of the peptide fragments produced by lysylendopeptidase digestion. Based on analysis by fluorescence ELISA, as many as 16 of the 18 patient sera tested, reacted to the disc abalone tropomyosin. The same patient sera also reacted to the disc abalone paramyosin, although rather less potently than to tropomyosin, suggesting that paramyosin is a major allergen. Immunoblotting data showed that IgE-reactive paramyosin is distributed in some species of molluscs other than the disc abalone. Interestingly, cross-reactivity between paramyosin and tropomyosin was demonstrated by inhibition immunoblotting and inhibition ELISA.     

Improvement of selective removal of heavy metals in cyanobacteria by NaOH treatment

In the freshwater cyanobacterium, Tolypothrix tenuis, treatment with 0.1 M NaOH increased its Cd-selective adsorption ability in the presence of Ca(2+) or Mg(2+). The selective adsorption was also achieved by other alkaline treatments. Energy-distributed spectroscopy analysis revealed that Cd(2+) was found mainly on the surface of non-treated cells, whereas it was distributed throughout the cell after NaOH treatment. The alkaline treatment was effective in increasing the selective adsorption ability of the cyanobacterium for other bivalent heavy metals such as Cu(2+), Pb(2+) and Zn(2+). The treatment was also applicable to Anabaena variabilis and Microcystis aeruginosa, which are typical cyanobacteria causing algal blooms. The main binding site of Cd(2+) in NaOH-treated cells is assumed to be the carboxyl groups because the binding ability of the cells was diminished by the esterification of carboxyl groups. These results suggest that alkaline treatment of cyanobacteria is a useful technique for producing biosorbents having highly specific binding abilities for heavy metals.     

Di(2-ethylhexyl) phthalate contamination of retail packed lunches caused by PVC gloves used in the preparation of foods

Plasticizer contamination of foods sold in retail packed lunches and set lunches in restaurants was determined by GC/MS. The phthalate esters were as follows: diethyl, dipropyl, dibutyl, dipentyl, dihexyl, butylbenzyl, dicyclohexyl, di(2-ethylhexyl), dioctyl, diisooctyl (mixture of isomers) and diisononyl (mixture). Di(2- ethylhexyl) adipate was also determined. Sixteen packed lunches and ten set lunches were analysed, and in all samples the concentration of di(2-ethylhexyl) phthalate (DEHP) was the highest, at 0.80-11.8 mg/ kg in packed lunches and 0.012-0.30 mg/kg in set lunches. The DEHP content of five packed lunches exceeded 1.85 mg, which is the EU tolerable daily intake (TDI) for a person of 50 kg body weight. Foodstuffs that were components of the packed lunches were taken from the factory at each step of preparation and phthalates were determined. For example, chicken contained 0.08 mg/kg DEHP when uncooked, 13.1 mg/ kg after frying and 16.9 mg/kg after packing. Disposable PVC gloves used in the preparation of foods were apparently the source of high DEHP concentrations. The gloves used during cooking or packaging were sprayed with 68% (w/w) ethanol to sterilize them. PVC gloves from the factory contained 22 or 41% by weight of DEHP. To confirm the link with the contamination problem, samples of boiled rice, croquette and boiled dry radish were handled in the laboratory with PVC gloves containing 30% (w/w) DEHP. DEHP migration levels of 0.05 mg/kg in rice or 0.33 mg/kg in croquette, and 11.1 mg/kg in radish were found. The alcohol sprayed onto the gloves increased the migration of DEHP to 2.03 mg/kg in rice, 2.45 mg/ kg in croquette, and 18.4 mg/kg in radish.     

Determination and quantification of the kokumi peptide, γ-glutamyl-valyl-glycine,in commercial soy sauces

Recent studies have demonstrated that kokumi substances, such as glutathione, are perceived through the calcium-sensing receptor (CaSR), and screening by CaSR assay and sensory evaluation has shown that γ-glutamyl-valyl-glycine (γ-Glu-Val-Gly) is a potent kokumi peptide. In this study, the contents of γ-Glu-Val-Gly in six commercial brands of dark-coloured soy sauces, two brands of light-coloured soy sauce, and one brand of white soy sauce, were investigated by high performance liquid chromatography–tandem mass spectrometry (LC/MS/MS), followed by derivatization with 6-aminoquinoyl-N-hydroxysuccinimidyl-carbamate (AQC). The analyses indicated that γ-Glu-Val-Gly was present in all investigated soy sauces at concentrations ranging from 0.15 to 0.61 mg/dl, demonstrating that it is widely distributed in soy sauces.