Molecular properties of the two-component cell lysis system encoded by prophage phigaY of Lactobacillus gasseri JCM 1131T: cloning, sequencing, and expression in Escherichia coli

Shotgun cloning of the Lactobacillus gasseri JCM 1131T whole DNA yielded two recombinant plasmids, p118gaY1 and p118gaY2, which directed cell lysis activity. Sequencing analysis revealed that the two plasmids carried almost identical inserted genes in following orders (truncated genes, in parentheses): in p118gaY1, (orf149)-orf92-holgaY-lysgaY-orf35-attL-(mnaAgaY1); in p118gaY2, (orfXgaY1)-orf169-orf149-orf92-holgaY-lysgaY-orf35-attP-(intgaY). The lysgaY-encoded protein (designated as LysgaY, 33.7 kDa) showed significant homology with putative muramidases (peptidoglycan-degrading enzyme) of the Lactobacillus phage phiadh, Lj965, Lj928, LL-H, mv4, and mv1. By zymogram analysis, LysgaY overproduced in Escherichia coli exhibited lytic activity towards 17 Gram-positive bacterial strains, including lactobacilli, lactococci, and staphylococci. The holgaY-encoded protein (15.7 kDa) contained three potential transmembrane helices, resembling putative holins (cytoplasmic membrane-disrupting protein) of Lj928 and Lj965. On the other hand, another clone p118gaYR obtained by EcoRI-shotgun cloning carried the (ptsCgaY1)-attR-(intgaY) genes. Three sequences, attL, attP, and attR, had a 47-bp common (core) sequence, and the core of attR was located in 3' region of a potential tRNA(Arg) gene. These results suggested that (i) attL and attR are phage-host junctions, left- and right-arms, respectively, (ii) attP is a phage attachment site, and (iii) intgaY is an integrase gene for phage integration and/or excision. After mitomycin C-induction, phage particles were demonstrated by electron microscopy. The prophage (phigaY) is somewhat leaky in the host, and has the two-component lysis system (HolgaY-LysgaY), closely resembling that of Lj928 as well as Lj965.     

Lipid droplets: size matters

The lipid droplet (LD), an organelle that exists ubiquitously in various organisms, from bacteria to mammals, has attracted much attention from both medical and cell biology fields. The LD in white adipocytes is often treated as the prototype LD, but is rather a special example, considering that its size, intracellular localization and molecular composition are vastly different from those of non-adipocyte LDs. These differences confer distinct properties on adipocyte and non-adipocyte LDs. In this article, we address the current understanding of LDs by discussing the differences between adipocyte and non-adipocyte LDs.     

Distribution Behavior of Nb,Ta, and Pa as Homologues of Db in Cation Exchange and Solid-Liquid and Liquid-Liquid Extractions by Aliquat 336 from Hydrochloric Acid

Detailed chemical studies on transactinide elements will clarify their characteristic properties caused by strong relativistic effect. In this work, to realize chemical study on transactinide element ₁₀₅Db, cation exchange, and solid-liquid and liquid-liquid extractions of micro amounts of Nb, Ta (homologues of Db), and Pa (pseudo homologue) by Aliquat 336 were performed employing hydrochloric acid. Clearly different chloride complex formations and distribution reaction kinetics were observed among these elements, and the present results are useful for studying the chemical properties of Db. Based on these results, we propose suitable experimental conditions for Db.     

The impact of air contaminants on PEMFC performance and durability

The impact of air contaminants such as sulfur compounds (SO₂, H₂S) and nitrogen compounds (NO_x and NH₃) was investigated using subscale fuel cells. The severity of the effect of these impurities varies depending on the contaminants. Among air contaminants, sulfur compounds cause the most severe performance loss due to decrease of available Pt sites for oxygen reduction reaction (ORR). We found that sulfur compounds adsorbed on Pt surface tend to be oxidized to sulfate at 0.9 V and higher potentials. The cell performance can be recovered partially by excursions to high potentials due to increase of available Pt sites. Furthermore, flushing the cathode with high humidity gases results in almost complete recovery of the cell performance. We conclude that these recovery effects are due to oxidation/removal of the contaminants from the Pt surface.     

Online time-differential perturbed angular correlation study with an O beam - Residence sites of oxygen atoms in highly oriented pyrolytic graphite

The online time-differential perturbed angular correlation (TDPAC) method was applied to a study of the physical states of a probe ¹⁹F, the β⁻ decay product of ¹⁹O (t_1/2 = 26.9 s), implanted in highly oriented pyrolytic graphite. The observed magnitude of the electric field gradient at the probe nucleus, ∣V_zz∣ = 2.91(17) × 10²² V m⁻², suggests that the incident ¹⁹O atoms are stabilized at an interlayer position with point group C_3v. Exhibiting observed TDPAC spectra having a clear sample-to-detector configuration dependence, we demonstrate the applicability of the present online method with a short-lived radioactive ¹⁹O beam.     

Fabrication of nano-sized oxide composite coatings and photo-electric conversion/electron storage characteristics

Titanium dioxide TiO₂ can be used as a photo-anode to give generated electrons to the metal substrate under illumination. The transition metal oxide such as iron oxide Fe₂O₃ can be used to store electrons generated by the photo-electric conversion function of TiO₂ under the illuminated situation while the electrons are discharged from the transition metal oxide to the metal substrate in the dark. In this paper, coatings of nano-sized composite of TiO₂ and Fe₂O₃ were fabricated by the Warm Spray process, in which the feedstock powder is accelerated by a supersonic gas jet with speed above 1.0 km s^- 1 and temperature between 800 and 2500 K, and then impacted onto the target substrate continuously to form coatings. The coatings of TiO₂ and Fe₂O₃ nano-composite fabricated by Warm Spray showed no thermal deterioration such as phase transformation and particle growth of the feedstock during the spray process. The coatings fabricated by the Warm Spray had larger photo-current and the electron charge/discharge capacity than that by a conventional HVOF process. In addition, these characteristics were improved by decreasing the primary particle size of TiO₂ and Fe₂O₃.     

Noncontact measurement of deep tissue absorption coefficient using Spatially Resolved Near‐Infrared Spectroscopy

We examined the influence of probe‐tissue distance on the relationship between the deep tissue absorption coefficient and the spatial profile of light intensity by Monte Carlo simulation and in vivo experiments, using noncontact spatially resolved near‐infrared spectroscopy (SRS). These results suggest that noncontact SRS can be reliably used for noncontact measurement of the absorption coefficient and oxygen saturation of deep tissues. © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.