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Y Oono

Publications and source records attributed to Y Oono.

At least 19 recordsLinked to original sources
PubMed1998

age Mutants of Arabidopsis exhibit altered auxin-regulated gene expression.

An Arabidopsis transgenic line was constructed expressing beta-glucuronidase (GUS) via the auxin-responsive domains (AuxRDs) A and B (BA-GUS) of the PS-IAA4/5 gene in an indoleacetic acid (IAA)-dependent fashion. GUS expression was preferentially enhanced in the root elongation zone after treatment of young seedlings with 10(-7) M IAA. Expression of the BA-GUS gene in the axr1, axr4, and aux1 mutants required 10- to 100-fold higher auxin concentration than that in the wild-type background. GUS expression was nil in the axr 2 and axr 3 mutants. The transgene was used to isolate mutants exhibiting altered auxin-responsive gene expression (age). Two mutants, age1 and age2, were isolated and characterized. age1 showed enhanced sensitivity to IAA, with strong GUS expression localized in the root elongation zone in the presence of 10(-8) M IAA. In contrast, age2 exhibited ectopic GUS expression associated with the root vascular tissue, even in the absence of exogenous IAA. Morphological and molecular analyses indicated that the age1 and age2 alleles are involved in the regulation of gene expression in response to IAA.

Arabidopsis↗
PubMed1997

Reconstructing potential energy functions from simulated force-induced unbinding processes.

One-dimensional stochastic models demonstrate that molecular dynamics simulations of a few nanoseconds can be used to reconstruct the essential features of the binding potential of macromolecules. This can be accomplished by inducing the unbinding with the help of external forces applied to the molecules, and discounting the irreversible work performed on the system by these forces. The fluctuation-dissipation theorem sets a fundamental limit on the precision with which the binding potential can be reconstructed by this method. The uncertainty in the resulting potential is linearly proportional to the irreversible component of work performed on the system during the simulation. These results provide an a priori estimate of the energy barriers observable in molecular dynamics simulations.

Binding Sites↗
PubMed1997

Molecular dynamics study of unbinding of the avidin-biotin complex.

We report molecular dynamics simulations that induce, over periods of 40-500 ps, the unbinding of biotin from avidin by means of external harmonic forces with force constants close to those of AFM cantilevers. The applied forces are sufficiently large to reduce the overall binding energy enough to yield unbinding within the measurement time. Our study complements earlier work on biotin-streptavidin that employed a much larger harmonic force constant. The simulations reveal a variety of unbinding pathways, the role of key residues contributing to adhesion as well as the spatial range over which avidin binds biotin. In contrast to the previous studies, the calculated rupture forces exceed by far those observed. We demonstrate, in the framework of models expressed in terms of one-dimensional Langevin equations with a schematic binding potential, the associated Smoluchowski equations, and the theory of first passage times, that picosecond to nanosecond simulation of ligand unbinding requires such strong forces that the resulting protein-ligand motion proceeds far from the thermally activated regime of millisecond AFM experiments, and that simulated unbinding cannot be readily extrapolated to the experimentally observed rupture.

Avidin↗
PubMed1996

[Efficacy of sulbactam/cefoperazone in respiratory tract infections in elderly patients with underlying respiratory diseases].

We examined the clinical effect of sulbactam/cefoperazone (SBT/CPZ) on respiratory tract infections in elderly patients (from 65 to 91, average 70.8) with underlying respiratory diseases. Thirty (30) patients (25 men and 5 women) were registered and SBT/CPZ (2 g/day) divided into two doses, was administered intravenously through drip infusion. The efficacy rate was 63% (excellent in 1 patient and good in 18 patients). No significant difference in efficacy was found among patient's age groups (group 1: 65-69, group 2: 70-74, group 3: 75-79, group 4: > 80). Bacterial eradication rate was 50% (6 out of 12 strains). An adverse reaction occurred in one patient, who experienced uticaria. Laboratory abnormalities, which were increasing with their ages, were observed in 12 patients during the study. These results suggest that SBT/CPZ was effective, but we found it is important to use caution in the treatment of elderly patients on respiratory tract infections with underlying respiratory diseases.

Aged↗
PubMed1995

Characterization of two members (ACS1 and ACS3) of the 1-aminocyclopropane-1-carboxylate synthase gene family of Arabidopsis thaliana.

The nucleotide sequences of two highly homologous 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS; EC 4.4.1.14)-encoding genes, ACS1 and ACS3, of Arabidopsis thaliana (At) have been determined. The sequence analysis shows that ACS3 is a pseudogene representing a truncated version of ACS1. The missing region of ACS3 corresponding to the fourth exon of ACS1 has been shown by Southern analysis to be absent in the At genome. The chromosomal locations of the five members of the At ACS multigene family have been determined. The results show that each family member resides on a different chromosome. This observation suggests that the ACS3 pseudogene originated by a partial inter-chromosomal gene duplication. The ACS1 polypeptide contains all the conserved and characteristic domains found in the ACC synthase isoenzymes from various plant species, but is unable to express ACS activity in Escherichia coli and yeast. The predicted amino-acid sequence of ACS1 is missing the highly conserved tripeptide, Thr-Asn-Pro (TNP), between Ile204 and Ser205. Introduction of TNP into ACS1 restores the ACS activity, whereas its removal from the enzymatically active ACS2 results in a loss of activity. The results suggest that TNP is crucial for expression of ACS activity in E. coli.

Amino Acid Sequence↗
PubMed1995

[Evaluation of photon-counting X-ray radiography for the detection of pulmonary nodule: a preliminary report on experimental and clinical studies].

To evaluate the utility of photon counting X-ray radiography (quantum radiography: QR) for the detection of pulmonary nodules, experimental and clinical studies were performed in comparison with conventional X-ray (CXR). In the experimental study, spatial resolution was analyzed by using the micro-chart method. The simulated nodule detection study was performed by using a chest phantom. The results were evaluated by means of ROC analysis. In the clinical study, both images of CXR and QR were evaluated in a case of metastatic lung tumor. In the experimental study, the spatial resolution of QR was 200 microns. QR was superior to CXR in detecting simulated nodules in all areas. In clinical cases, QR was superior to CXR in depicting not only normal structures but also retrocardiac and retrodiaphragmatic pulmonary nodules.

Carcinoma, Renal Cell↗
PubMed1993

[Primary chylopericardium: a case report].

A case of primary chylopericardium in a 54 year-old-man was reported. Despite 3 times of pericardiocentesis, the pericardial fluid accumulated rapidly. After the fenestration of pericardium, a small cannula was inserted for the thoracic ductgram which showed a clearly visible duct upward to the angulus venosus and an abnormal branch near the bifurcation of the trachea spilling some contrast material into the pericardial cavity. Ligation and division of the thoracic duct including an abnormal branch was performed from its entry to the thorax for a length of 13 cm upward. The postoperative course was uneventful and chest X-ray film taken 6 months after surgery showed no accumulation of chyle in the pericardium and pleural cavity.

Chyle↗
PubMed1991

Agrobacterium rhizogenes lacZ-rolC gene expression in Escherichia coli: detection of the product in transgenic plants using RolC-specific antibodies.

The rolC sequence of the Agrobacterium rhizogenes Ri plasmid was fused in-frame to the 3' end of the lacZ gene in plasmid pEX3. The fusion protein RolC-beta-galactosidase was accumulated as insoluble inclusion bodies in Escherichia coli. Antibodies were raised in rabbits against the fusion protein. After affinity purification, RolC-specific antibodies were found to react with a 22-kDa polypeptide prepared from roots of transgenic tobacco plants possessing a rolC gene. The result of differential centrifugation suggested that RolC is present in the soluble fraction of transformed cells.

Amino Acid Sequence↗