ANGUSTIFOLIA3 Signaling Coordinates Proliferation between Clonally Distinct Cells in Leaves

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Highlights? AN3 is produced specifically in mesophyll cells and moves into epidermal cells ? AN3 participates in the control of epidermal cell proliferation ? AN3 signaling is essential for normal leaf development ? AN3 movement does not require the action of the type II chaperonin complex     

A region corresponding to second aspartate-rich motif in tryptophan isoprenylating enzyme,ComQ, serves as a substrate-binding site

Posttranslational isoprenylation of a tryptophan residue identified from Bacillus quorum sensing pheromone, ComX pheromone, is unique and essential for the bioactivity. A modifying enzyme, ComQ, forms ComX pheromone from the ComX precursor and isoprenyl pyrophosphate and exhibits moderate similarity to isoprenyl pyrophosphate synthases. We investigated non-conserved region in ComQ, corresponding to isopentenyl pyrophosphate binding region of the synthases, using in vitro cell-free isoprenylation. These results suggested that the only conserved aspartic acid residue in the region of ComQ is critical for enzyme activity and responsible for ComX binding. Our findings should contribute to basic understanding of the mechanism of tryptophan isoprenylation.     

Heterologous expression of geraniol dehydrogenase for identifying the metabolic pathways involved in the biotransformation of citral by Acinetobacter sp. Tol 5

ABSTRACT

The biotransformation of citral, an industrially important monoterpenoid, has been extensively studied using many microbial biocatalysts. However, the metabolic pathways involved in its biotransformation are still unclear, because citral is a mixture of the trans-isomer geranial and the cis-isomer neral. Here, we applied the heterologous expression of geoA, a gene encoding geraniol dehydrogenase that specifically converts geraniol to geranial and nerol to neral, to identify the metabolic pathways involved in the biotransformation of citral. Acinetobacter sp. Tol 5 was employed in order to demonstrate the utility of this methodology. Tol 5 transformed citral to (1R,3R,4R)-1-methyl-4-(1-methylethenyl)-1,3-cyclohexanediol and geranic acid. Biotransformation of citral precursors (geraniol and nerol) by Tol 5 transformant cells expressing geoA revealed that these compounds were transformed specifically from geranial. Our methodology is expected to facilitate a better understanding of the metabolic pathways involved in the biotransformation of substrates that are unstable and include geometric isomers.     

Comparative proteome analysis of the embryo proper and yolk sac membrane of day 11.5 cultured rat embryos

BACKGROUND: Proteomic analysis of cultured postimplantation rat embryos is expected to be useful for investigation into embryonic development. Here we analyzed protein expression in cultured postimplantation rat embryos by two-dimensional electrophoresis (2-DE) and mass-spectrometric protein identification. METHODS: Rat embryos were cultured from day 9.5 for 48 h or from day 10.5 for 24 h. Proteins of the embryo proper and yolk sac membrane were isolated by 2-DE and differentially analyzed with a 2-D analysis software. Selected protein spots in the 2-DE gels were identified by matrix-assisted laser desorption/ionization-time of flight tandem mass spectrometric analysis and protein database search. RESULTS: About 800 and 1,000 protein spots were matched through the replicate 2-DE gels each from one embryo in the embryo proper and yolk sac membrane, respectively, and virtually the same protein spots were observed irrespective to the length of culture period. From protein spots specific to the embryo proper (126 spots) and yolk sac membrane (304 spots), proteins involved in tissue-characteristic functions, such as morphogenesis and nutritional transfer, were identified: calponin, cellular retinoic acid binding protein, cofilin, myosin, and stathmin in the embryo proper, and Ash-m, dimerization cofactor of hepatocyte nuclear factor, ERM-binding phosphoprotein, cathepsin, and legumain in the yolk sac membrane. CONCLUSION: Proteomic analysis of cultured postimplantation rat embryos will be a new approach in developmental biology and toxicology at the protein level.     

Different Mode of Afferents Determines the Frequency Range of High Frequency Activities in the Human Brain: Direct Electrocorticographic Comparison between Peripheral Nerve and Direct Cortical Stimulation

Physiological high frequency activities (HFA) are related to various brain functions. Factors, however, regulating its frequency have not been well elucidated in humans. To validate the hypothesis that different propagation modes (thalamo-cortical vs. cortico-coritcal projections), or different terminal layers (layer IV vs. layer II/III) affect its frequency, we, in the primary somatosensory cortex (SI), compared HFAs induced by median nerve stimulation with those induced by electrical stimulation of the cortex connecting to SI. We employed 6 patients who underwent chronic subdural electrode implantation for presurgical evaluation. We evaluated the HFA power values in reference to the baseline overriding N20 (earliest cortical response) and N80 (late response) of somatosensory evoked potentials (HFA_SEP(N20) and HFA_SEP(N80)) and compared those overriding N1 and N2 (first and second responses) of cortico-cortical evoked potentials (HFA_CCEP(N1) and HFA_CCEP(N2)). HFA_SEP(N20) showed the power peak in the frequency above 200 Hz, while HFA_CCEP(N1) had its power peak in the frequency below 200 Hz. Different propagation modes and/or different terminal layers seemed to determine HFA frequency. Since HFA_CCEP(N1) and HFA induced during various brain functions share a similar broadband profile of the power spectrum, cortico-coritcal horizontal propagation seems to represent common mode of neural transmission for processing these functions.     

Chemical Composition and Character Impact Odorants in Volatile Oils from Edible Mushrooms

The aim of this study was to investigate the chemical composition and the odor‐active components of volatile oils from three edible mushrooms, Pleurotus ostreatus, Pleurotus eryngii, and Pleurotus abalonus, which are well‐known edible mushrooms. The volatile components in these oils were extracted by hydrodistillation and identified by GC/MS, GC‐olfactometry (GC‐O), and aroma extract dilution analysis (AEDA). The oils contained 40, 20, and 53 components, representing 83.4, 86.0, and 90.8% of the total oils in P. ostreatus, P. eryngii, and P. abalonus, respectively. Odor evaluation of the volatile oils from the three edible mushrooms was also carried out using GC‐O, AEDA, and odor activity values, by which 13, eight, and ten aroma‐active components were identified in P. ostreatus, P. eryngii, and P. abalonus, respectively. The most aroma‐active compounds were C₈‐aliphatic compounds (oct‐1‐en‐3‐ol, octan‐3‐one, and octanal) and/or C₉‐aliphatic aldehydes (nonanal and (2E)‐non‐2‐enal).     

Encouragement of Enzyme Reaction Utilizing Heat Generation from Ferromagnetic Particles Subjected to an AC Magnetic Field

We propose a method of activating an enzyme utilizing heat generation from ferromagnetic particles under an ac magnetic field. We immobilize α-amylase on the surface of ferromagnetic particles and analyze its activity. We find that when α-amylase/ferromagnetic particle hybrids, that is, ferromagnetic particles, on which α-amylase molecules are immobilized, are subjected to an ac magnetic field, the particles generate heat and as a result, α-amylase on the particles is heated up and activated. We next prepare a solution, in which α-amylase/ferromagnetic particle hybrids and free, nonimmobilized chitinase are dispersed, and analyze their activities. We find that when the solution is subjected to an ac magnetic field, the activity of α-amylase immobilized on the particles increases, whereas that of free chitinase hardly changes; in other words, only α-amylase immobilized on the particles is selectively activated due to heat generation from the particles.     

Ventilatory and heart rate chemosensitivity in track-and-field athletes

Fifty-four male track-and-field athletes and 18 male non-athletes were examined by isocapnic progressive hypoxia and CO2 rebreathing tests. Ventilatory and heart rate (HR) responses to hypoxia were analysed by a hyperbolic relationship and the ventilatory response to hypercapnia by a linear regression. The results showed that ventilatory sensitivity during hypoxia was significantly attenuated in the long-distance runners and sprinters compared to the non-athletes. Although heart rate sensitivity during hypoxia in none of the athletes showed a significant difference compared to that of the non-athletes, baseline HR in the long-distance runners was significantly lower than that of the non-athletes. None of the athletes showed significant differences in ventilatory sensitivity during hypercapnia compared to the non-athletes.     

Plant-inducible recombination between the 25 bp border sequences of T-DNA in Agrobacterium tumefaciens

Summary We developed a model system for detecting and assaying the circular forms of T-DNA which may be generated in Agrobacterium by intramolecular recombination between the 25 bp border repeats of T-DNA. We demonstrated using this system that the DNA region flanked by the 25 bp direct repeats is in fact circularized by recombination between these repeats in cells of Agrobacterium cocultured with tobacco protoplasts. Furthermore, quantitative analysis of the recombination revealed the following: (1) the recombination is also induced when the agrobacterial cells are incubated in protoplast-free conditioned medium prepared by filtering the protoplast culture. The conditioned medium is effective, even after it has been heated at 100°C. (2) The DNA region encompassing the virulence region of the Ti-plasmid is required for recombination. (3) The recombination takes place only between 25 bp repeats with the same orientation. On the basis of these results, we conclude that the circular form of T-DNA is generated by homologous recombination between the border repeats which is mediated by gene product(s) encoded by the virulence region of the Ti-plasmid. Either the recombination itself, or the expression of the virulence gene(s) responsible for the recombination, is induced by diffusible and heatstable factor(s) secreted by plant cells.