An aerobic, polarly flagellated marine bacterium that produces a prodigiosinlike pigment was isolated from the red-spotted culture beds of Laminaria japonica. Five isolates had unique bacteriolytic activity for both Gram-positive and -negative bacteria, which had never been observed among Alteromonas or related species. The isolates were identified as the causative agent of red spot disease of L. japonica seeds. The phenotypic features of the isolates were similar to these of Pseudoalteromonas rubra ATCC 29570T, but they could be differentiated using 10 traits (growth at 37 "C, requirement for organic growth factors, bacteriolytic activity, utilization of sucrose, N-acetylglucosamine, fumarate, succinate, D-galactose, L-proline and acetate). The G+C content of DNAs from the isolates was 4 4 4 6 mol0/o. The isolates constitute a new species, distinct from the other A/teromonas and Pseudoalteromonas species, as shown by DNA-DNA hybridization experiments and phylogenetic clustering of 165 rRNA gene sequences, for which the name Pseudoalteromonas bacteriolytica sp. nov. (type strain = IAM 145953 is proposed. A set o f phenotypic features which differentiate this new species from closely related Pseudoalteromonas and Akeromonas species is provided.
Rod photoreceptor cGMP phosphodiesterase (PDE6) consists of a catalytic subunit complex (Palphabeta) and two inhibitory subunits (Pgamma). In the accompanying article, using bovine photoreceptor outer segment homogenates, we show that Pgamma as a complex with the GTP-bound transducin alpha subunit (GTP-Talpha) dissociates from Palphabetagammagamma on membranes, and the Palphabetagammagamma becomes Pgamma-depleted. Here, we identify and characterize the Pgamma-depleted PDE. After incubation with or without guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS), Palphabeta complexes are extracted. When a hypotonic buffer is used, Palphabetagammagamma, Palphabetagamma, and a negligible amount of a Palphabeta complex containing Pgamma are isolated with GTPgammaS, and only Palphabetagammagamma is obtained without GTPgammaS. When an isotonic buffer containing Pdelta, a prenyl-binding protein, is used, Palphabetagammagammadelta, Palphabetagammadeltadelta, and a negligible amount of a Palphabeta complex containing Pgamma and Pdelta are isolated with GTPgammaS, and Palphabetagammagammadelta is obtained without GTPgammaS. Neither Palphabeta nor Palphabetagammagamma complexed with GTPgammaS-Talpha is found under any condition we examined. Palphabetagamma has approximately 12 times higher PDE activity and approximately 30 times higher Pgamma sensitivity than those of Palphabetagammagamma. These results indicate that the Pgamma-depleted PDE is Palphabetagamma. Isolation of Palphabetagammagammadelta and Palphabetagammadeltadelta suggests that one C-terminus of Palphabeta is involved in the Palphabetagammagamma interaction with membranes, and that Pgamma dissociation opens another C-terminus for Pdelta binding, which may lead to the expression of high PDE activity. Cone PDE behaves similarly to rod PDE in the anion exchange column chromatography. We conclude that the mechanisms for PDE activation are similar in mammalian and amphibian photoreceptors as well as in rods and cones.
Ultrathin MgB2
films were fabricated by using a co-evaporation method. We increased the Mg evaporation rate up to
32 nm s−1
by adjusting the chamber configuration and succeeded in fabricating
MgB2
thin films with high quality at a high substrate temperature of
350 °C. The thickness dependence of the thin film characteristics showed that an ultrathin film with a
thickness of 4.2 nm had superconducting properties with a critical temperature of 8 K and a resistivity
of 1200 µΩ cm
at 40 K. The mean roughness of a 15 nm thick
MgB2
thin film was 0.18 nm, which indicated that our
MgB2
thin films have the potential to fabricate sub-micron size patterns.
Bulk In x Ga 1−x As is an excellent lattice-matched substrate material for InGaAs-based laser diodes. However, it is very difficult to grow compositionally homogeneous In x Ga 1−x As single crystal. The growth of single crystal with homogeneous composition using the newly developed traveling liquidus zone (TLZ) growth method is expected. In the TLZ method, cylindrically shaped polycrystalline starting material with a graded compositional profile is the basic requirement. This paper presents some results of micro-Raman scattering studies of the compositional fraction in these starting materials. The compositions evaluated by Raman scattering in various In x Ga 1−x As wafer-type samples show good agreement with those examined by the standard method of chemical analysis. Compositional profiles obtained from as-ground and polished surfaces have been compared to understand the necessity of surface polishing in our experiments. The results presented here demonstrate that micro-Raman scattering is one of the best non-destructive methods for analyzing the entire compositional range of InGaAs compound materials.
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