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Recently, an anomalous photovoltaic effect in a BiFeO3(BFO) thin film has attracted much attention. In this research, Pt/BFO/Pt coplanar capacitors have been prepared using striped- and single-domain structured BFO thin films, and the influence of the polarization direction of incident violet laser light (λ = 405 nm) on the photovoltage of these capacitors has been investigated. In a specific geometry, both coplanar capacitors, the one using a striped-domain and the other using a single-domain structured BFO thin film showed anomalous photovoltages above band gap of BFO, indicating that an anomalous photovoltage should be observed under randomly-polarized light illumination such as that by a halogen lamp.

Epitaxial BiFeO3(BFO) thin films have been prepared on La-doped (001) SrTiO3substrates (La-STO) by using magnetic-field-assisted pulsed laser deposition. X-ray diffraction patterns of the epitaxial BFO thin films prepared under magnetic fields of 0, 0.1, and 0.4 T show only (00ℓ) diffraction peaks without secondary phases. From the results of reciprocal space mapping for all epitaxial BFO thin films, (003) reflections show splitting spots, and asymmetric spots of (−103) and (103) reflections exhibit a rhombohedral structure. The microstructure of the epitaxial thin films was modified by the strength of magnetic field, and a columnar structure was shown in the film prepared under a high deposition rate for a magnetic field of 0.4 T. The polarization versus electric field hysteresis loops were obtained at room temperature (RT) in all the epitaxial films; in particular, the remanent polarization for the epitaxial film prepared under a magnetic field of 0.1 T was 46 µC/cm2at RT while the current density was reduced in comparison with those of other epitaxial films.

The insertion effect of Bi-excess layers on stoichiometric BiFeO3thin films prepared by chemical solution deposition is investigated. A stoichiometric BiFeO3thin film with both the Bi-excess top and bottom surface layers shows improved crystallinity with the remanent polarization of 65 μC/cm2at 80 K, which is larger than for BiFeO3film prepared by the same process using stoichiometric solution. These results are attributed to the reduction of the imperfect crystal at the interface between the BiFeO3film and electrode. By inserting Bi-excess layers, the saturated magnetization of all the films becomes smaller than that of the film using stoichiometric solution. Bi-excess surface layers at the top and bottom interfaces are an effective way to obtain good ferroelectric properties.

A cell wall component that bound to HeLa cells (HeLa cell‐binding CWC) was isolated from a clinical isolate of Staphylococcus aureus. The HeLa cell‐binding CWC was resistant to heat (100 C, 1 hr) and proteases, did not stain with Coomassie Brilliant Blue R‐250 on SDS‐PAGE but stained as a broad band with antiserum against the strain on Western blots. These data suggest that the HeLa cell‐binding CWC is not a protein, and may be teichoic acid. Purified teichoic acid bound to HeLa cells, whereas fractions without teichoic acid did not. In Western blots, HeLa cell‐binding CWC appeared as a broad band of less than 35 kDa, similar to that of purified teichoic acid. These data suggest that the HeLa cell‐binding CWC obtained in this study is teichoic acid. Teichoic acid inhibited S. aureusadherence to HeLa cells and bound to the cells time and dose dependently, in a saturable and reversible manner, and therefore appears to be an adhesin of S. aureusto HeLa cells.

The Staphylococcus aureusautolysin gene, atl, encodes a unique 138‐kDa protein (ATL) with amidase and glucosaminidase domains. ATL has been suggested to undergo proteolytic processing to generate two extracellular peptidoglycan hydrolases, 51‐kDa endo‐β‐N‐acetylglucosaminidase (51‐kDa GL) and 62‐kDa N‐acetylmuramyl‐L‐alanine amidase (62‐kDa AM). To investigate cell‐associated bacteriolytic enzymes for atlgene products, proteins were extracted from the cells as follows. The cells were exposed to 3 M LiCl followed by 4% SDS. Thereafter, the cells were disrupted and again extracted with 4% SDS. Whole SDS‐stable cell‐associated bacteriolytic proteins were extracted without disrupting the cells. Exposure to 3 M LiCl released major 138‐, 115‐, 85‐, 62‐ and 51‐kDa bacteriolytic proteins, and subsequent 4% SDS extraction released major 138‐ and 115‐kDa bacteriolytic proteins. These bacteriolytic proteins were missing in extracts of atlmutant RUSAL2 (S. aureusRN450 atl:: Tn551). Immunoblotting studies suggest that these are all atlgene products: the 138‐kDa protein is an ATL with a cleaved signal sequence; the 115‐and 85‐kDa proteins are intermediates; and the 51‐ and 62‐kDa proteins are cell‐associated 51‐kDa GL and 62‐kDa AM, respectively. The trypsin susceptibility of these proteins suggests that they are located outside the cell membrane. Differences in extractability and immunoelectron microscopic studies suggest that atlgene products are associated with cells in two different ways, LiCl extractable and non extractable. We suggest that the 138‐kDa ATL undergoes processing through intermediate proteins (115‐ and 85‐kDa proteins) to mature as the active cell cluster‐dispersing enzymes 51‐kDa GL and 62‐kDa AM on the cell surface.

Profiles of cell‐associated bacteriolytic activities and those in the culture supernatant of Staphylococcus aureusFDA209P at various stages of growth were analyzed using sodium dodecyl sulfate‐polyacrylamide gels containing Micrococcus luteusor S. aureus. In the logarithmic growth phase, the cell‐associated bacteriolytic activities extracted with Triton X‐100 contained a number of bacteriolytic proteins, the profiles of which were similar to those we reported elsewhere (Sugai, M., Akiyama, T., Komatsuzawa, H., Miyake, Y., and Suginaka, H.(1990) J. Bacteriol., 172, 6494‐6498). The proteins include P1, P2, P7, P9, PX, P13, P18 and other minor components. At the stationary growth phase, the bacteriolytic band‐profile of the Triton X‐100 extract changed dramatically. P1, P7 and P9 disappeared, and the other minor bands had markedly decreased band intensities. On the other hand, P2, PX, P13, and P18 retained their band intensities during the stationary growth phase. The band intensities of P7, P13, PX, and P18 increased in the supernatant during the logarithmic growth phase. These results indicated that the bacteriolytic band‐profile changes during growth.