Taxonomical Study of Glutamic Acid Accumulating Bacteria,Micrococcus glutamicus nov. sp.

Taxonomical studies of a new group of strains of glutamics acid accumulating bacteria isolated in our laboratory were carried out. It was found that these strains belong to Genus Micrococcus because they are gram-positive, none-sporulating, and catalase possessing cocci. They are also pale yellowish, aerobic, and capable to reduce nitrate. Moreover, they neither utilize ammonium salt as a sole source of nitrogen in Hucker’s medium nor liquefy gelatin. From these observations, it seems that they are related to M. aurantiacus and M. epidermidis. However, our strains are different from them in the manner of acid production in milk and lactose media, and also in pigmentation, serological reactions and glutamic acid accumation.

The name of Micrococcus glutamicus nov. sp. was, therefore proposed to these strains.

The phenomenon of cell elongation and characteristics of the pigments of these strains was also investigated.     

Materials forPythium flora of Japan VIII Two species ofPythium:P. pyrilobum andP. oligandrum

Two species ofPythium (P. pyrilobum, P. oligandrum) having spherical sporangia with complex subglobose elements were isolated from the crown of creeping bentgrass [Agrostis palustris (cv. Penncross)] and from vegetable field soil, respectively. They are reported for the first time in Japan.     

Interaction of a bacterial flagellar chaperone FlgN with FlhA is required for efficient export of its cognate substrates

FlgN chaperone acts as a bodyguard to protect its cognate substrates, FlgK and FlgL, from proteolysis in the cytoplasm. Docking of the FlgN-FlgK complex with the FliI ATPase of the flagellar type III export apparatus is key to the protein export process. However, a ΔfliH-fliI flhB(P28T) mutant forms some flagella even in the absence of FliH and FliI, raising the question of how FlgN promotes the export of its cognate substrates. Here, we report that the interaction of FlgN with an integral membrane export protein, FlhA, is directly involved in efficient protein export. A ΔfliH-fliI flhB(P28T) ΔflgN mutant caused extragenic suppressor mutations in the C-terminal domain of FlhA (FlhA(C) ). Pull-down assays using GST affinity chromatography showed an interaction between FlgN and FlhA(C) . The FlgN-FlgK complex bound to FlhA(C) and FliJ to form the FlgN-FlgK-FliJ-FlhA(C) complex. The FlgN-FlhA(C) interaction was enhanced by FlgK but not by FliJ. FlgN120 missing the last 20 residues still bound to FlgK and FliJ but not to FlhA(C) . A highly conserved Tyr-122 residue was required for the interaction with FlhA(C) . These results suggest that FlgN efficiently transfers FlgK/L subunits to FlhA(C) to promote their export.     

Dynamic features of homodimer interfaces calculated by normal‐mode analysis

Knowledge of the dynamic features of protein interfaces is necessary for a deeper understanding of protein–protein interactions. We performed normal‐mode analysis (NMA) of 517 nonredundant homodimers and their protomers to characterize dimer interfaces from a dynamic perspective. The motion vector calculated by NMA for each atom of a dimer was decomposed into internal and external motion vectors in individual component subunits, followed by the averaging of time‐averaged correlations between these vectors over atom pairs in the interface. This averaged correlation coefficient (ACC) was defined for various combinations of vectors and investigated in detail. ACCs decrease exponentially with an increasing interface area and r‐value, that is, interface area divided by the entire subunit surface area. As the r‐value reflects the nature of dimer formation, the result suggests that both the interface area and the nature of dimer formation are responsible for the dynamic properties of dimer interfaces. For interfaces with small or medium r‐values and without intersubunit entanglements, ACCs are found to increase on dimer formation when compared with those in the protomer state. In contrast, ACCs do not increase on dimer formation for interfaces with large r‐values and intersubunit entanglements such as in interwinding dimers. Furthermore, relationships between ACCs for intrasubunit atom pairs and for intersubunit atom pairs are found to significantly differ between interwinding and noninterwinding dimers for external motions. External motions are considered as an important factor for characterizing dimer interfaces.     

Simultaneous brightness contrast of foraging Papilio butterflies

This study focuses on the sense of brightness in the foraging Japanese yellow swallowtail butterfly, Papilio xuthus. We presented two red discs of different intensity on a grey background to butterflies, and trained them to select one of the discs. They were successfully trained to select either a high intensity or a low intensity disc. The trained butterflies were tested on their ability to perceive brightness in two different protocols: (i) two orange discs of different intensity presented on the same intensity grey background and (ii) two orange discs of the same intensity separately presented on a grey background that was either higher or lower in intensity than the training background. The butterflies trained to high intensity red selected the orange disc of high intensity in protocol 1, and the disc on the background of low intensity grey in protocol 2. We obtained similar results in another set of experiments with purple discs instead of orange discs. The choices of the butterflies trained to low intensity red were opposite to those just described. Taken together, we conclude that Papilio has the ability to learn brightness and darkness of targets independent of colour, and that they have the so-called simultaneous brightness contrast.     

Heat treatment of retinal pigment epithelium induces production of elastic lamina components and antiangiogenic activity

Age-related macular degeneration (AMD) is the leading cause of blindness in the Western world. In advanced AMD, new vessels from choriocapillaris (CC) invade through the Bruch's membrane (BrM) into the retina, forming choroidal neovascularization (CNV). BrM, an elastic lamina that is located between the retinal pigment epithelium (RPE) and CC, is thought to act as a physical and functional barrier against CNV. The BrM of patients with early AMD are characterized by decreased levels of antiangiogenic factors, including endostatin, thrombospondin-1 (TSP-1), and pigment epithelium-derived factor (PEDF), as well as by degeneration of the elastic layer. Motivated by a previous report that heat increases elastin expression in human skin, we examined the effect of heat on human ARPE-19 cell production of BrM components. Heat treatment stimulated the production of BrM components, including TSP-1, PEDF, and tropoelastin in vitro and increased the antiangiogenic activity of RPE measured in a mouse corneal pocket assay. The effect of heat on experimental CNV was investigated by pretreating the retina with heat via infrared diode laser prior to the induction of CNV. Heat treatment blocked the development of experimental CNV in vivo. These findings suggest that heat treatment may restore BrM integrity and barrier function against new vessel growth.