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S Obata

Publications and source records attributed to S Obata.

At least 55 records · Page 3Linked to original sources
PubMed1993

Crystallization and preliminary X-ray diffraction studies of Bacillus stearothermophilus farnesyl diphosphate synthase expressed in Escherichia coli.

Thermostable farnesyl diphosphate synthase (EC 2.5.1.10) from Bacillus stearothermophilus, which was overexpressed in Escherichia coli, has been crystallized by the vapor-diffusion procedure. Tetragonal crystals were obtained using ammonium sulfate as a precipitant. The crystals diffracted X-rays to about 3 A resolution. The diffraction pattern indicated that the space group is I4(1)22 with unit-cell dimensions of a = b = 114 A and c = 247 A. It is thought that the asymmetric unit comprises two or three molecules of farnesyl diphosphate synthase.

Alkyl and Aryl Transferases↗
PubMed1993

Protocadherins: a large family of cadherin-related molecules in central nervous system.

Using the polymerase chain reaction, we have isolated numerous rat and human cDNAs of which the deduced amino acid sequences are highly homologous to the sequences of the extracellular domain of cadherins. The entire putative coding sequences for two human proteins defined by two of these cDNAs have been determined. The overall structure of these molecules is very similar to that of classic cadherins, but they have some unique features. The extracellular domains are composed of six or seven subdomains that are very similar to those of cadherins, but have characteristic properties. The cytoplasmic domains, on the other hand, have no significant homology with those of classic cadherins. Since various cDNAs with almost identical features were obtained also from Xenopus, Drosophila and Caenorhabditis elegans, it appears that similar molecules are expressed in a variety of organisms. We have tentatively named these proteins protocadherins. They are highly expressed in brain and their expression appears to be developmentally regulated. The proteins expressed from the two full-length cDNAs in L cells were approximately 170 or 150 kDa in size, and were localized mainly at cell-cell contact sites. Moreover, the transfectants showed cell adhesion activity.

Amino Acid Sequence↗
PubMed1993

Thermostable farnesyl diphosphate synthase of Bacillus stearothermophilus: molecular cloning, sequence determination, overproduction, and purification.

The structural gene for thermostable farnesyl diphosphate synthase from Bacillus stearothermophilus was cloned, sequenced, and overexpressed in Escherichia coli cells. A 1,260-nucleotide sequence of the cloned fragment was determined. This sequence specifies an open reading frame of 891 nucleotides for farnesyl diphosphate synthase. The deduced amino acid sequence shows a 42% similarity with that of E. coli FPP synthase [Fujisaki et al. (1990) J. Biochem. 108, 995-1000]. Comparison with prenyltransferases from a wide range of organisms, from bacteria to human, revealed the presence of seven highly conserved regions. In contrast to thermolabile prenyltransferases, which have four to six cysteine residues, the thermostable farnesyl diphosphate synthase carries only two cysteine residues. This enzyme is also unique in that some of the amino acids that are fully conserved in equivalents from other sources are replaced by functionally different amino acids. Construction of an overproducing strain provided a sufficient supply of this enzyme and it was purified to homogeneity. The purified recombinant enzyme is immunochemically identical with the native B. stearothermophilus enzyme, and it is not inactivated even after treatment at 65 degrees C for 70 min.

Alkyl and Aryl Transferases↗
PubMed1993

Spontaneous submucosal dissection of the esophagus.

A 41-year-old woman was found to have had spontaneous submucosal dissection of the esophagus by esophagoscopy. Food ingestion was postulated to have been an initiating factor in this instance. Conservative therapy was sufficient in this case. Patients who complain of sore throat with retrosternal pain and an obstructed sensation on swallowing or mild hematemesis should be examined by esophagoscopy for evidence of this disorder.

Adult↗
PubMed1993

[Ultrasonographic study of low-lying placenta and its clinical significance].

Low-lying placenta is reported to cause PROM, preterm labor, and abnormal bleeding during pregnancy and labor, but it has not been clearly defined how low the placenta has to be implanted to categorize it as "low-lying". In the present investigation, using ultrasonography, the distance between the placental implantation site and the internal cervical os in relation to gestational outcome was investigated to clarify the diagnosis and clinical significance of low-lying placenta. 1. Placental implantation site in normal gestation 1) In none of the cases at week 28 of gestation or later, the distance was 2cm or less between the lower edge of the placenta and the internal cervical os. At week 32 or later, the distance was 3cm or less in none. 2) At week 36 or later, it was 5 cm or more in all cases. 2. Low-lying placenta in association with gestational or labor outcome When "low-lying placenta" was tentatively defined as the placenta implanted within 2cm from the internal os and "normal placenta" as one implanted 2.1 cm or more from the internal os, the following findings were obtained. 1) The incidence of low-lying placenta was 2.8% (49/1,771) at gestational weeks 20 < or = - < 24, 0.96% (17/1,771) up to gestational week 29, and 0.73% (13/1,771) up to 1 week prior to labor. 2) The incidence of bleeding during gestation, preterm labor, PROM and emergency C/S was higher in the 13 cases with low-lying placenta remaining until labor than in 1,749 cases (p < 0.05) normally sited.(ABSTRACT TRUNCATED AT 250 WORDS)

Cesarean Section↗
PubMed1992

Morphogenesis of the photoreceptor outer segment during postnatal development in the mouse (BALB/c) retina.

Disc formation of rod photoreceptor cells in developing BALB/c mice retinas was studied by rapid freeze, freeze-substitution, freeze-etching, immunocytochemistry, and myosin S-1 decoration methods. Freeze-substituted photoreceptor cells contained variously shaped vesicles in the apical swelling of the connecting cilium or the base of the outer segment during postnatal development. Rapid freezing successfully arrested pinocytosis; the fusion of small vesicles to give large ones, and the compression of certain vesicles (0.3-0.6 micron) appears to lead gradually to the formation of the so-called discs. We therefore propose that membranous discs are formed by the fusion of small pinocytotic vesicles and their subsequent compression. Discs formed in this way were partially stacked, but were ordered at random during the early developmental stages. During development, a partial stack of discs was progressively rearranged to a regular form as seen in mature outer segments. Cytoskeletal actin was expected to be involved in the disc formation; it was demonstrated in the distal axoneme of the connecting cilium during development and showed no change in its distribution. However, the polarity of the actin filaments, as revealed by myosin S-1 decoration in early developmental stages, was much more variable than in the adult. Barbed ends of actin filaments were associated with the plasma membrane or the membrane of vesicles. We also found actin filaments coiled up helically on ciliary microtubules.

Actins↗
PubMed1992

Use of strip biopsy in a case of early duodenal cancer.

In a 67-year-old man referred for investigation of an abdominal mass, upper gastrointestinal endoscopy incidentally revealed a polypoid lesion with a central depression in the duodenum. The abdominal mass causing gastric compression was shown by ultrasonography and CT scan to be cyst anterior to the pancreas. Biopsy of the duodenal lesion, however, was suggestive of carcinoma. Strip biopsy was therefore performed. Histological examination showed a tubular adenocarcinoma with invasion limited to the mucosa, and indicated that complete endoscopic resection had been achieved. Follow-up over ten months did not reveal recurrence of the tumor. Strip biopsy would appear to be a safe and efficient method for management of early gastrointestinal tract cancer also in the duodenum.

Adenocarcinoma↗
PubMed1992

[Isospora belli infection in a patient with adult T-cell leukemia].

An adult T cell leukemia (ATL) accompanied with Isospora belli infection was described. A 65-year-old male was admitted to our hospital because of a two month history of watery diarrhea. On admission, physical examination showed slight pallor but no detectable superficial lymphadenopathies. Hepatosplenomegaly was not observed. Laboratory examination revealed a leukocyte count 5,500/microliters with 10% abnormal lymphoid cells. A majority of the abnormal lymphoid cells expressed both CD 4 and CD 8 antigens. The patient was diagnosed as chronic ATL, since anti-HTLV-1 antibody in his serum and monoclonal integration of HTLV-1 proviral DNA in his peripheral mononuclear cells were detected. Isospora belli was found in his feces thereafter, and trimethoprim/sulfamethoxazole was effective for diarrhea. In Japan, there have been only 9 reported cases of lymphoproliferative disorders (including five ATL patients) accompanied with Isospora belli infection. From the descriptions in those reports, these 9 cases might all be ATL patients.

Aged↗
PubMed1991

Identification and characterization of protein kinase C-related enzymes in frog retina.

We isolated two types of protein kinase C-related enzymes (fPKC) in frog (Rana catesbeiana) retina. Three sequential steps of column chromatography of DEAE-cellulose, butyl-Toyopearl, and hydroxylapatite were carried out and resulted in the separation of two types of distinct Ca2+/phospholipid-dependent protein kinase activities. These proteins reacted with antibodies raised against synthetic peptides based on the predicted amino acid sequences of rat protein kinase C delta or zeta subspecies, and showed molecular masses of 90 and 75 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, respectively. Immunocytochemical analysis of 90 and 75K fPKC in frog retina revealed that the 75K fPKC was localized in the outer segment of cone cells and in the microvillar projections of Müller cells. These results suggested that fPKCs play differential roles on the photosignal transduction in frog retina.

Amino Acid Sequence↗
PubMed1990

Effects of etoposide (VP-16) on the survival and progression of cultured HeLa S3 cells through the cell cycle.

The survival of cultured HeLa S3 cells and their progression through the cell cycle after exposure to Etoposide (VP-16) were studied. The dose survival curve of exponentially growing cells was of a biphasic nature; the curve had an exponential slope starting from a small shoulder, and finally attained a plateau against increasing concentrations of the drug. Throughout the cell cycle, VP-16 exerted its main killing activity on cells in the late S and G2 phases, whereas cells in the G1 phase were resistant to the drug. By using a low concentration of VP-16, which allowed 85% of the treated cells to survive, it was found that the inhibition of the cell progression by the drug was greatest in the late S and G2 phases.

Cell Cycle↗
PubMed1990

Alteration of the specificity of the Streptomyces subtilisin inhibitor by gene engineering.

We have altered the amino acid at the center of the reactive site (methionine 73) of Streptomyces subtilisin inhibitor (SSI) by site-directed and cassette mutagenesis. Replacement by lysine or arginine resulted in trypsin inhibitory activity, replacement only by lysine gave inhibition of lysyl endopeptidase, and replacement by tyrosine or tryptophan resulted in inhibition of alpha-chymotrypsin. The four mutant SSIs retained their native activity against subtilisin BPN'. Thus by altering only one amino acid residue at the reactive site of SSI to the substrate specificity of the respective protease we could successfully change its inhibitory profile.

Amino Acid Sequence↗
PubMed1990

[Plasma concentration of polymorphonuclear leukocyte elastase-alpha 1-proteinase inhibitor complex in patients with gastric ulcer].

To test the possible participation of activated leukocytes in the pathogenesis of gastric ulcer, plasma levels of polymorphonuclear leukocyte-elastase-alpha 1-proteinase inhibitor complex (PMN-EC), a discerning indicator for the activation of leukocytes, were determined in patients with gastric ulcer. Plasma levels of PMN-EC in patients with gastric ulcer (185.2 +/- 21.6 micrograms/l, mean +/- S.E.M.) were significantly higher than those in normal healthy subjects (67.6 +/- 4.4 micrograms/l, p less than 0.01). On the other hand, plasma levels of C-reactive protein and sialic acid increased in only 17.8% and 7.1% of patients with gastric ulcer, respectively. No significant correlation was observed between PMN-EC and the plasma levels of CRP or sialic acid. Plasma levels of PMN-EC decreased with the healing of the ulcerative lesion as judged by gastro-endoscopic observation. These findings suggested that activation of leukocytes might deeply be correlated with the pathologic mechanism of gastric ulceration and the measurement of PMN-EC might be useful for monitoring the patients with gastric ulcer.

Humans↗
PubMed1989

Molecular cloning and nucleotide sequence determination of gene encoding Streptomyces subtilisin inhibitor (SSI).

A gene for Streptomyces subtilisin inhibitor (SSI) from Streptomyces albogriseolus S-3253 was cloned into E. coli plasmid pBR322 using two oligodeoxyribonucleotides corresponding to Asp68 to Pro77 and Asn99 to Gly107 of the protein, respectively. The SSI gene was localized on a 1.8-kbp BglII/SalI fragment. The nucleotide sequence of this 1.8-kbp fragment was determined by the dideoxy sequencing method. The amino acid sequence of the mature SSI coding region derived from the nucleotide sequence determination corresponded exactly to that from protein sequencing analysis. The nucleotide sequence analysis showed the presence of a putative signal peptide comprising 31 amino acids preceding the mature SSI region. The major transcriptional start point was identified to be 60 nucleotides upstream from the putative initiation codon for translation by the primer extension method. The -45 to -25 region upstream from transcriptional start point was quite homologous to that of CTC promoter of Bacillus subtilis. The overall G + C content of this 1.8-kbp fragment was 72%. On the other hand, an extremely high G + C content (96%) was found at the third letter of codons in the SSI coding region.

Bacterial Proteins↗
PubMed1989

High-level expression in Streptomyces lividans 66 of a gene encoding Streptomyces subtilisin inhibitor from Streptomyces albogriseolus S-3253.

A secretory expression system for Streptomyces subtilisin inhibitor (SSI) was established in a heterologous host, Streptomyces lividans 66, by introducing the 1.8-kbp BglII/SalI fragment containing SSI gene into the Streptomyces multicopy vector, pIJ 702. The expression of SSI did not depend on the orientation of the 1.8-kbp BglII/SalI fragment or on the promoter for tyrosinase gene (mel) in pIJ 702, which suggested that this fragment also carries the SSI promoter. The expressed SSI in S.lividans 66 was secreted into the culture medium in a large amount, as observed with the original strain, S. albogriseolus S-3253. Amino acid sequence analysis showed that the SSI secreted from S. lividans 66 contained three additional amino acid residues in the NH2-terminal region. The inhibitory activity toward subtilisin BPN' and the antigenic activity of the SSI secreted from S. lividans 66 were found to be identical with those of authentic SSI.

Amino Acid Sequence↗