Search PubMed⌕ Search

Biomedical subjects

A Iida

Publications and source records attributed to A Iida.

At least 109 records · Page 6Linked to original sources
PubMed1995

Fungal metabolites. XX. Effect of proline residue on the structure of ion-channel-forming peptide, trichosporin B-VIa.

The secondary structures of an ion-channel-forming icosapeptaibol, trichosporin B-VIa, and its Aib14-substituted derivative containing no Pro were investigated on the basis of CD and various NM experiments in methanol. Trichosporin B-VIa has a fully helical structure with a kink stabilized by a 1<--4 hydrogen-bond between the Leu12 CO and Val15 NH. The helical structure is composed of 3(10)-helix in the N-terminal first turn and the C-terminal moiety following Leu12, and alpha-helix in the middle region. In contrast, the Aib14 derivative predominantly has a straight alpha-helical structure except for a 3(10)-helix region in the N-terminal first turn.

Amino Acid Sequence↗
PubMed1995

Fungal metabolites. XVIII. New membrane-modifying peptides, trichorozins I-IV, from the fungus Trichoderma harzianum.

New membrane-modifying peptides, trichorozins I-IV, have been isolated from conidia of the fungus Trichoderma harzianum. Their amino acid sequences were clearly determined by spectrometric methods and, furthermore, they were synthesized by the solution-phase method. Trichorozins are a family of the class of peptaibols and are composed of 11 residues including an amino alcohol. Trichorozins exhibited voltage-dependent ion channel-like activity in lipid bilayers.

Amino Acid Sequence↗
PubMed1995

Fungal metabolites. XIX. Structural elucidation of channel-forming peptides, trichorovins-I-XIV, from the fungus Trichoderma viride.

Trichorovins (TV)-I-XIV are new antibiotic peptides obtained from conidia of the fungus Trichoderma viride. The peptide mixture of TVs was repeatedly fractionated by preparative HPLC until individual TVs showed a single peak on their analytical HPLC chromatograms. Nevertheless, FAB-MS or NMR indicated that each of TVs-I-XIV was composed of at least two components. We attempted to elucidate their structures within the fractions by electrospray ionization (ESI)-MS, FAB-MS, FAB-MS/MS and NMR. TVs generally have molecular weights of approximately 1100-1200 Da, and are characterized by an acetylated N-terminus, the presence of an aminoalcohol, e.g. leucinol, isoleucinol or valinol, at the C-terminus, and eleven residues including three alpha-aminoisobutyric acids in the molecule. Thus, it was determined that TVs belong to the class of peptaibols.

Amino Acid Sequence↗
PubMed1995

Craniosynostosis with joint contractures, ear deformity, cleft palate, scoliosis, and other features.

A case of craniosynostosis with joint contractures, ear deformity, cleft palate, scoliosis, and many other features is presented. The patient's skull was round with craniosynostosis of the coronal suture. The fingers were slender and long; the finger joints were contracted. Trismus was also present. Contracture of the temporomandibular joint was suspected. The helices were flat, antihelices were minimal, and the ears protruded. Furthermore, the facial and cranial features of this patient included mild hypertelorism, ocular proptosis, short pons nasi, flat radix nasi, mild retrognathia, and small oral fissure. In the oral cavity, a relatively wide cleft extended from the soft palate to the uvula. A frontal chest radiograph revealed a mild scoliosis. Differential diagnoses are discussed in reported syndromes with craniosynostosis.

Abnormalities, Multiple↗
PubMed1994

Homologous cysteine proteinase genes located on two different chromosomes from Trypanosoma rangeli.

DNA fragments were obtained by the polymerase chain reaction (PCR) using genomic DNA from T. rangeli as template and oligonucleotide primers encoding the active site amino acids of cysteine proteinase. After amplification by PCR, several DNA products were observed. These were purified and used as templates for a second round of PCR. This resulted in two DNA products of 475 and 498 bp. The 498 bp DNA (Tr-CP) contained both the sense and antisense primer sequences, and encoded a polypeptide having substantial homology with eukaryotic cysteine proteinases. The other product (Tr-DMR), which lacked the antisense primer sequence, encoded a polypeptide having homology with the DNA mismatch repair gene from Saccharomyces cerevisiae. The overall homology of the Tr-CP-encoded polypeptide to the cysteine proteinases from other trypanosome species was 69% identity (T. cruzi) and 73% identity (T. brucei), respectively. Northern blot analysis revealed that the Tr-CP gene was specifically expressed in T. rangeli as a 1.7 kb mRNA. A karyotype map of the chromosomes was also performed using pulsed-field gradient gel electrophoresis and Southern blot hybridization with these genes. T. rangeli has 14 chromosome bands ranging from 350 kb to 1.6 Mb, which were fewer in number and smaller in size compared with those from T. cruzi. The Tr-CP fragment and the Tr-DMR fragment hybridized with equal intensity on chromosome 1 (350 kb) and chromosome 2 (470 kb), respectively. These results suggest that non-pathogenic T. rangeli contains a conserved gene corresponding to the cysteine proteinase or a closely related enzyme, and that there is more than one copy of this gene, each found on different chromosomes.

Amino Acid Sequence↗
PubMed1994

Isolation and characterization of a novel gene encoding nuclear protein at a locus (D11S636) tightly linked to multiple endocrine neoplasia type 1 (MEN1).

To identify a gene responsible for multiple endocrine neoplasia type 1 (MEN1), we attempted to isolate potentially transcribable fragments from cosmid clones derived from a region on chromosome 11q13 where genetic linkage studies and analyses of loss of heterozygosity in MEN1-associated tumors have localized the MEN1 gene. By an exon-amplification method, we recovered three exon-like sequences from one of these clones, cCI11-367, and using these sequences as probes we were able to isolate new clones from cerebrum, cerebellum, and fetal-liver cDNA libraries. Sequence analysis of these cDNA clones revealed that the transcribed gene, designated ZFM1, encodes a novel 623-amino-acid protein containing domains with interesting structural properties including a nuclear transport domain, a metal binding motif, and glutamine- and proline-rich regions. Analysis by the reverse-transcriptase polymerase chain reaction (RT-PCR) indicated that this gene is expressed in various tissues including endocrine organs such as thyroid gland, pancreas, adrenal gland, and ovary. These data suggest that ZFM1 might be a candidate for mutations that cause MEN1.

Amino Acid Sequence↗
PubMed1994

Fungal metabolites. X. The effect of peptide antibiotics, trichosporin-Bs, on the respiratory activity of mitochondria.

The effect of the trichosporin-Bs, peptide antibiotics, on the respiration of mitochondria was investigated. Trichosporin-Bs stimulated the respiratory rate of state 4 rat liver mitochondria in a dose-dependent manner. The maximum respiratory rate obtained by trichosporin-Bs was essentially the same as for 2,4-dinitrophenol and SF6847. Trichosporin-B-VIb released oligomycin-inhibited respiration of mitochondria. This means that trichosporin-Bs are uncouplers of oxidative phosphorylation. The stimulatory effect of trichosporin-B-VIb, a component of trichosporin-Bs, on mitochondrial respiration was increased by inorganic phosphate but not by other permeant anions studied. These results suggest that the stimulation of mitochondrial respiration by trichosporin-B-VIb is mediated by the same mechanism as is operating in the case of hypelcins and alamethicins. Furthermore, the relative potencies of trichosporin-Bs on the mitochondrial respiration and their relative hydrophobicities were examined. A clear relationship was observed between the uncoupling potencies of trichosporin-Bs and their relative hydrophobicities.

2,4-Dinitrophenol↗
PubMed1994

Fungal metabolites. XVII. Synthesis and NMR study of ion channel-forming peptides, trichosporin B-VIa and its derivative.

A membrane-modifying peptide antibiotic, trichosporin B-VIa, having catecholamine secretion-inducing activity on bovine adrenal chromaffin cells has been synthesized. Aib14-Trichosporin B-VIa, in which Pro14 was replaced by Aib, has also been synthesized to modify the secondary structure of trichosporin B-VIa. Sequence-specific 1H-NMR assignments of both peptides in methanol were achieved by using two-dimensional NMR techniques.

Amino Acid Sequence↗
PubMed1994

Fungal metabolites. XIII. Isolation and structural elucidation of new peptaibols, trichodecenins-I and -II, from Trichoderma viride.

Three new groups of peptaibols, trichodecenins, trichorovins and trichocellins, have been isolated from conidia of the fungus, Trichoderma viride. The structures of trichodecenins-I and -II were established by positive-ion fast-atom bombardment, collision-induced dissociation mass spectrometry and two-dimensional NMR spectroscopy. Trichodecenins-I and -II have a (Z)-4-decenoyl group, six amino acid residues and a leucinol moiety in the molecules. Trichodecenin-II was synthesized by the solution-phase method.

Amino Acid Sequence↗
PubMed1993

Identification and characterization of the tktB gene encoding a second transketolase in Escherichia coli K-12.

We isolated a transposon Tn10 insertion mutant of Escherichia coli K-12 which could not grow on MacConkey plates containing D-ribose. Characterization of the mutant revealed that the level of the transketolase activity was reduced to one-third of that of the wild type. The mutation was mapped at 63.5 min on the E. coli genetic map, in which the transketolase gene (tkt) had been mapped. A multicopy suppressor gene which complemented the tkt mutation was cloned on a 7.8-kb PstI fragment. The cloned gene was located at 53 min on the chromosome. Subcloning and sequencing of a 2.7-kb fragment containing the suppressor gene identified an open reading frame encoding a polypeptide of 667 amino acids with a calculated molecular weight of 72,973. Overexpression of the protein and determination of its N-terminal amino acid sequence defined unambiguously the translational start site of the gene. The deduced amino acid sequence showed similarity to sequences of transketolases from Saccharomyces cerevisiae and Rhodobacter sphaeroides. In addition, the level of the transketolase activity increased in strains carrying the gene in multicopy. Therefore, the gene encoding this transketolase was designated tktB and the gene formerly called tkt was renamed tktA. Analysis of the phenotypes of the strains containing tktA, tktB, or tktA tktB mutations indicated that tktA and tktB were responsible for major and minor activities, respectively, of transketolase in E. coli.

Amino Acid Sequence↗
PubMed1993

[A case of advance colon cancer responding to sequential methotrexate and 5-fluorouracil therapy].

A 60-year-old female was diagnosed by X-ray examination and endoscopy as ascending colon cancer. Ultrasonography and computed tomography revealed two metastatic tumors in the liver. Abdominal surgery revealed peritoneal disseminations, massive lymph node metastasis and direct invasion of the transverse colon and ileum. From pathological examination the diagnosis was moderately differentiated adenocarcinoma. After right hemi-colectomy, sequential methotrexate and 5-fluorouracil therapy as well as oral administration of UFT, liver metastasis disappeared and no sign of ascites was found in this case. Complete response time was over 8 months. There have been no severe complications.

Adenocarcinoma↗
PubMed1992

Amplification of protein expression in a cell free system.

Large quantities of a catalytically active protein have been produced in a cell free system. More than 10(9) copies of protein were produced from each DNA plasmid containing DNAfol, the bacterial gene encoding dihydrofolate reductase (DHFR). The strategy employed, denoted gene amplification with transcription/translation (GATT), involves sequential coupling of (i) DNA amplification by the polymerase chain reaction (PCR) and (ii) in vitro RNA transcription by T7 RNA polymerase, followed by (iii) translation of the run-off transcripts in a rabbit reticulocyte system. The protein product had the expected size (18 kDa) and catalyzed the NADPH-dependent reduction of 7,8-dihydrofolic acid to 5,6,7,8-tetrahydrofolic acid as efficiently as authentic DHFR. Potential applications of the strategy include large scale production of enzymes containing synthetic amino acids and facilitation of the characterization of the function of genes encountered in genomic mapping studies.

Cell-Free System↗
PubMed1992

New nonradioactive microspheres and more sensitive X-ray fluorescence to measure regional blood flow.

We developed new nonradioactive microspheres and used more sensitive X-ray fluorescence spectrometers than used previously to measure regional blood flow in the heart and other organs. We demonstrated the chemical stability of eight kinds of heavy element-loaded microspheres and validated their use for regional blood flow measurement by comparing duplicate flows measured with radioactive and/or nonradioactive microspheres in both acute and chronic dog experiments. The wavelength-dispersive spectrometer (Philips PW 1480) has a higher sensitivity than the previously described X-ray fluorescent system and reduced the number of microspheres required for accurate measurement. The fine energy resolution of this system makes it possible to increase the numbers of different kinds of microspheres to be quantitated, but at present only eight kinds are available. We also used a synchrotron radiation-excited energy dispersive spectrometer. The monochromatic synchrotron radiation allowed us to obtain much higher signal-to-background ratios of X-ray fluorescence spectra than with the wavelength-dispersive system (50 dB more for Zr-loaded microspheres) and will enable analysis of fluorescent activity in smaller regions (< 20 mg) than the radioactive method does.

Animals↗
PubMed1992

Responses to intravenous sedation by elderly patients at the Hokkaido University Dental Hospital.

Geriatric patients who undergo intravenous sedation require careful intraoperative management, because respiratory and circulatory depression usually accompanies the administration of recommended adult sedative doses. This study examined results when a single benzodiazepine, diazepam or flunitrazepam, was carefully titrated to a clinical endpoint of conscious sedation. A total of 335 cases was divided into seven age groups. Mean sedative doses gradually decreased with age. The 60- to 69-yr group required about 75% of the adult recommended dose, the 70- to 79-yr group required 40% to 60%, and the 80- to 89-yr group required 30% to 45%. Pulse oximetry values also declined with age; respiratory depression was observed mainly in elderly patients. Declines in blood pressure after benzodiazepine administration were not correlated with age. The rise in blood pressure normally observed intraoperatively was suppressed both in young as well as old patients. We conclude that intravenous conscious sedation in elderly patients reduces stress-induced cardiovascular stimulation and that respiratory depression may occur at even low sedative doses.

Adult↗
PubMed1991

Transient expression of beta-glucuronidase in Arabidopsis thaliana leaves and roots and Brassica napus stems using a pneumatic particle gun.

Successful transient expression of beta-glucuronidase (GUS) in Arabidopsis thaliana leaves and roots and Brassica napus stems was obtained after gene delivery with a pneumatic particle gun driven by compressed air. Effects of the pneumatic pressure used to accelerate the particles (accelerating pressure; 85 to 200 kg/cm2) and of preculture periods of plant tissues (0 to 6 days) on the efficiency of gene delivery were studied. In A. thaliana leaves, best results were obtained at 115 kg/cm2 of accelerating pressure and 3 days of preculture. In A. thaliana roots, the optimum was at 200 kg/cm2 of accelerating pressure and 3 days of preculture. These results indicate that both preculture period and accelerating pressure are vital factors that determine the efficiency of gene delivery by particle gun.

Atmospheric Pressure↗