Significance of cell electrokinetic properties determined by soft-particle analysis in bacterial adhesion onto a solid surface

The influence of extracellular polymeric substances (EPSs) on bacterial cell electrokinetic properties and on cell adhesion onto glass beads in connection with bacterial cell electrokinetic properties was investigated using 12 heterotrophic bacterial strains. Bacterial cell surface properties such as the softness 1/lambda and charge density ZN were determined by Ohshima's soft-particle analysis using the measured electrophoretic mobility as a function of ionic strength. In 10 of 12 strains, when EPSs covering the cell surface were removed, the softness of the cell decreased, indicating that EPS adsorption enhanced the ease of liquid fluid in the ion-penetrable layer on the cell surface. On the other hand, the negative charge density of the cell surface increased for 9 of 12 strains, suggesting that EPSs covering the cell surface decreased the negative charge density of the cell surface layer. In addition, the characteristics of bacterial cell adhesion onto glass beads were evaluated by the packed-bed method and the data were interpreted to indicate cell adhesiveness. As a result, the efficiency of cell adhesion onto glass beads increased as negative cell surface potential psi0 decreased, whereas there seemed to be no correlation between zeta potential and cell adhesiveness. Cell surface potential psi0, which was derived by taking the bacterial polymer layer with EPSs into consideration, provided a more detailed understanding of the electrokinetic properties of bacterial cells.     

Synthesis of 1,2:5,6-Di-O-isopropylidene-3-O-[3-(5-fluorouracil-1-yl)-propionoyi]-α-D-glucofuranose and its antitumor activity

In order to provide a less toxic 5-fluorouracil derivative, 1,2:5,6-di-O-isopropylidene-3-O-[3-(5-fluorouracill-yl)-propionoyl]-α-D-glucofuranose, which was the derivative of 5-fluorouracil combining indirectly to 3-position of diacetoneglucose, was synthesized, and its antitumor activity was tested.     

Immobilized aminoacylase on porous glass beads

Aminoacylase was immobilized on porous glass by two different coupling methods. One aminoacylase preparation was covalently bound to an alkylaminosilane derivative of porous glass with glutaraldehyde [alkylamino-porous glass-CVB-aminoacylase]; the other aminoacylase derivative was prepared by covalently binding the enzyme to arylaminosilane glass by diazotization [arylamino-porous glass-CVB-aminoacylase]. The enzyme activities of the immobilized aminoacylases were 3.2-13.0 U/ml glass for the former and 1.9-6.8 U/ml glass for the latter. The alkylamino-porous glass-CVB-aminoacylase showed excellent stability at pH 6-9 and at temperatures below 50°C. The derivative could be stored for more than 6 mo without appreciable loss of the activity. Continuous hydrolysis using the alkylamino-porous glass-CVB-aminoacylase packed in column was carried out for 54 days at 37°C, with a calculated half-life of 78 days. It was determined that alkylamino-porous glass-CVB-aminoacylase would be applicable in an industrial preparation of various l-amino acids from their dl forms.     

Random-phase-approximation calculations on triplet spectra of conjugated molecules

Random-phase approximations (RPA) have been applied to the calculation of the triplet π-π* transition spectra of 18 conjugated molecules in the framework of Pariser-Parr-Pople approximations. It is found that the normal RPA (n-RPA) shows the triplet instability for most molecules in the Nishimoto-Mataga approximation of electron-repulsion integrals. However, it is shown that this instability can be circumvented by the use of the renormalized RPA (r-RPA) in which the correlated ground states are calculated by the second-order perturbation theory. It is also shown that even in the n-RPA the suitable parametrization of electron-repulsion integrals removes this instability. It is ascertained that such an increasing order of energies as ω(n-RPA)<ω(Tamm-Dancoff approximation)<ω(r-RPA) holds for most of energy levels.     

Alternating copolymer of butadiene and propylene. III

Alternating copolymerizations of butadiene with propylene and other olefins were investigated by using VO(acac)₂–Et₃Al–Et₂AlCl system as catalyst. Butadiene–propylene copolymer with high degree of alternation was prepared with a monomer feed ratio (propylene/butadiene) of 4. Alternating copolymers of butadiene and other terminal olefins such as butene-1, pentene-1, dodecene-1, and octadiene-1,7 were also obtained. However, the butadiene–butene-2 copolymerization did not yield an alternating copolymer but a trans-1,4-polybutadiene.     

Classification of irreducible super-unitary representations ofsu(p,q/n)

In this paper we classify all the irreducible super-unitary representations ofsu(p,q/n), which can be integrated up to a unitary representation ofS(U(p,q)×U(n)), a Lie group corresponding to the even part ofsu(p,q/n). Note that a real form of the Lie superalgebrasl(m/n;) which has non-trivial superunitary representations is of the formsu(p,q/n)(p+q=m) orsu(m/r,s)(r+s=n). Moreover, we give an explicit realization for each irreducible super-unitary representation, using the oscillator representation of an orthosymplectic Lie superalgebra.     

Construction of Robust Ruthenium(salen)(CO) Complexes and Asymmetric Aziridination with Nitrene Precursors in the Form of Azide Compounds That Bear Easily Removable N‐Sulfonyl Groups

We synthesized new Ru(salen)(CO) complexes of high durability and achieved aziridination with good to excellent enantioselectivity by using azide compounds that contain an easily removable N‐sulfonyl group, such as the 2‐(trimethylsilyl)ethanesulfonyl group, as a nitrene precursor. Aziridination of less‐reactive α,β‐unsaturated esters (and amides) proceeded with excellent enantioselectivities, from which it is inferred that an electrophilic species is the active species of this reaction. The present asymmetric aziridination provides a useful tool for introducing optically active nonprotected amine groups.     

Poincaré-Invariant Coupled-Channel Models for Meson Photoproduction

A general procedure for constructing Poincaré-invariant mass operators in a helicity basis is presented. The procedure is developed in the framework of the instant form of relativistic quantum mechanics, but it can be easily extended to other forms. The method is used to extend a previously developed Poincaré-invariant coupled-channel model for the pion-nucleon system to include a photon-nucleon channel. This makes it possible to carry out calculations on photoproduction from nucleons that satisfy exactly the requirements of special relativity. Methods are given for deriving potentials that couple the photon-nucleon channel to the pion-nucleon channel. These potentials are invariant under gauge transformations of the photon's polarization vector. Amplitudes obtained by solving the Lippmann-Schwinger equations that arise from the Poincaré-invariant mass operators satisfy unitarity, and hence Watson's theorem for photoproduction amplitudes. The methods presented can also be used to develop models for the photoproduction of and mesons, as well as vector mesons. Received April 14, 1997; revised September 24, 1997; accepted for publication October 15, 1997     

Neutron-deuteron scattering in high partial waves

The simple formula is derived for calculating the n + d phase shifts for states with high relative orbital angular momentum. The only parameters appearing in the formula are the deuteron binding energy and the triplet effective range. The formula is tested by comparing it with the results of an exactly solvable model, and it is found to be quite accurate at low energies for L ? 3.