Chemical characterization of recombinant human epidermal growth factor

Human epidermal growth factor (EGF) produced from yeast and purified by ion-exchange and gel filtration chromatography was analysed by reversed-phase liquid chromatography (RP-LC) and showed two main peaks (EGF-1 and EGF-2) with different relative yields from batch to batch and similar biological activities (radioreceptor analysis). Each component isolated by RP-LC was reduced, carboxymethylated and digested with endopeptidase Lys-C and endopeptidase Glu-C separately. Each digest was analysed by fast atom bombardment mass spectrometry (FAB-MS) without further purification. It was verified that both EGF-1 and EGF-2 have the same amino acid sequence of human EGF except at the C-terminal end. EGF-2 lacks the C-terminal arginine and EGF-1 lacks the C-terminal leucine- arginine residues. The location of the SS bonds was also verified by FAB-MS of the peptide mixture obtained by 2% acetic acid hydrolysis. The fermentation and purification processes were followed by RP-LC and FAB-MS and allowed the amount of EGF-1 to be reduced to 10–15%, but intact EGF was never detected.     

The reactions of ethyl 3,4-dihydro-4-quinazolylacetate and its derivatives with cyclopentanone. An attempt at the synthesis of the 6,8-diazasteroid system VII

The reaction of ethyl 3,4-dihydro-4-quinazolylacetate ( 1a ) with cyclopentanone in the presence of trifluoroacetic acid gave mainly two decomposition products, carbostyril (VIII) and ethyl 2-aminocinnamate (IX). Two compounds which are suggested to have the 6,8-diazasteroid skeleton were also obtained in poor yield. Ethyl 3,4-dihydro-2-p-methoxyphenyl-4-quinazolylacetate (1b), however, gave 2-p-methoxyphenylquinazoline (XII) as a decomposition product and did not condense with cyclopentanone. Furthermore, two ethyl 3,4-dihydroquinazolylacetates substituted at the 2-position with cyclohexyl (1c) and methyl (1d) groups could not be converted to the expected diazasteroid system.     

Analytic self-mapping reducing to the identity mapping

Commentarii Mathematici Helvetici -     

Preparation of immobilized tannins for protein adsorption

Preparation and adsorption specificity of tannins immobilized by covalent binding on water-insoluble matrices were investigated. Immobilized tannins were prepared by condensing cyanogen bromide activated tannins with aminohexyl derivatives of several kinds of matrices. The most suitable matrix for the immobilization of tannin was alkali-treated cellulose powder. The concentration of sodium hydroxide solution for alkali treatment influenced the adsorption capacity of immobilized tannin for a protein, but temperature and time for alkali treatment did not. Immobilized tannins having spacers of long chain length exhibited high adsorption capacity for a protein. Chinese gallotannin was the most favorable ligand for protein adsorption. The immobilization of tannin on aminohexyl matrices was also possible by using epichlorohydrin instead of cyanogen bromide. The maximum adsorption capacity of the immobilized tannin for a protein was about 50 mg/ml of the absorbent. Immobilized tannin adsorbed proteins specifically but did not absorb low molecular weight compounds.     

Recent developments of optical fiber sensors for automotive use

Optical fiber sensing technologies are expected to apply for many future electronic control systems in automobiles, because of their inherent outstanding features, such as high noise immunity, high heat resistance, and flexible light propagation paths which can be applied to measure the movements and directions of the mobiles. In this paper, two typical applications of fiber sensing technologies in automobiles are described in detail. The combustion flame detector is one of the typical applications of a fiber spectroscopic technology which utilizes the feature of high noise and heat resistibility and remote sensibility. Measurement of engine combustion conditions, such as the detonation, the combustion initiation, and the air-fuel ratio, have been demonstrated in an experimental fiber sensing method. Fiber interferometers, such as a fiber gyroscope, have great possibilities in future mobile applications because they are applicable to many kinds of measurements for movements and physical variables. An optical fiber gyroscope utilizing the single polarized optical fiber and other optical devices has been developed. Quite an accurate measurement of vehicle position was displayed on a prototype navigation system which installed the fiber gyroscope as a rotational speed sensor.     

Further discussion of the cyclopolymerization of acrylic anhydride in terms of ring size control

Radical cyclopolymerization of acrylic anhydride (AA) was conducted under various polymerization conditions to yield highly cyclized polymer, and the content of the five-membered ring of cyclic poly-AA obtained was examined in detail. Five-membered ring formation was favored with increased solvent polarity, raised polymerization temperature, and decreased monomer concentration; the ring size of the cyclic structure could be controlled freely by choosing appropriate polymerization conditions. In addition to these results, the rate of polymerization and the molecular weight of the polymer were reduced under polymerization conditions where the five-membered ring formation was favored. Finally, a mechanistic discussion is given in order to interpret these results; a reaction scheme for propagation based on polymerization equilibrium is proposed.     

On the relationship between the genus and the cardinality of the maximum matchings of a graph

Lower bounds on the cardinality of the maximum matchings of graphs are established in terms of a linear polynomial of p, p⁽¹⁾, p⁽²⁾ and γ whose coefficients are functions of κ, where p is the number of the vertices of a graph, p⁽ⁱ⁾ the number of the vertices of degree i (i = 1,2), γ the genus and κ the connectivity.     

Application of an image-sensing camera to the measurement of length and velocity of marks printed on specimens

A solid-state image-sensing camera composed of a linear array of tiny silicon photodiodes is found to be effective for measuring the length between gloomy but clear marks and the velocity of a straight moving mark printed on the specimen. It can be applied to various kinds of measurement by exchanging the computer programs for processing the data. In this report the measurement errors due to both the size of the photodiode and its binary signal are discussed from the geometrical viewpoint. Program for measuring the length and velocity are developed theoretically and their validity is verified experimentally.     

EXPRESSION OF AN Anacystis nidulans PHOTOLYASE GENE IN Escherichia coli; FUNCTIONAL COMPLEMENTATION AND MODIFIED ACTION SPECTRUM OF PHOTOREACTIVATION

The Anacystis nidulans photolyase gene inserted in an expression vector plasmid was introduced into Escherichia coli cells and the production of Anacystis photolyase protein was confirmed by reaction with antibodies raised against photolyase purified from A. nidulans cells. The Anacystis photolyase functioned in photoreactivation repair defective E. coli cells. The E. coli transformants exhibited an action spectrum with a maximum around 380 nm similar to that of E. coli photolyase in contrast with the action spectrum of A. nidulans cells which has a maximum at 437 nm. These results indicate that the Anacystis photolyase produced in E. coli cells has enzymatic activity in spite of the apparent lack of its intrinsic 8-hydroxy-5-deazaflavin cofactor.