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T Yagi

Publications and source records attributed to T Yagi.

At least 19 recordsLinked to original sources
PubMed1992

A novel tyrosine kinase, hyk, expressed in murine embryonic stem cells.

To identify tyrosine kinases which play roles in mammalian early development, the 3' rapid amplification of cDNA ends (RACE) was performed on mouse embryonic stem (ES) cells. Among eight tyrosine kinases thus identified, we report here a novel tyrosine kinase, hyk (adhesion structures linked tyrosine kinase). The sequences of the 4.7 kb cDNA indicated the presence of RGD motif and three epidermal growth factor-like domains put between two immunoglobulin-like domains and three fibronectin type III domains in its extracellular region. It is strongly expressed in ES cells and later stages of embryos, but at low levels in midgestation embryos. It is also expressed at a low level in neural precursor cells from 10-day embryos, but at high levels in embryonic day 15 and neonatal brains. In adult tissues it is expressed ubiquitously.

Amino Acid Sequence↗
PubMed1992

Gene cluster of the energy-transducing NADH-quinone oxidoreductase of Paracoccus denitrificans: characterization of four structural gene products.

In previous reports from our laboratory, the three structural genes (NQO1, NQO2, and NQO3) of the energy-transducing NADH-quinone oxidoreductase of Paracoccus denitrificans were characterized [Xu, X., Matsuno-Yagi, A., & Yagi, T. (1991) Biochemistry 30, 6422-6428; (1991) Biochemistry 30, 8678-8684; (1992) Arch. Biochem. Biophys. 296, 40-48]. In this report, the four structural genes NQO4, NQO5, NQO6, and NQO7 of the same Paracoccus denitrificans oxidoreductase were cloned and sequenced. On the basis of sequence homology and immunological cross-reactivity, these genes encode counterparts of the 49-, 30-, and 20-kDa polypeptides and the mitochondrial DNA ND3 polypeptides of bovine mitochondrial complex I. These seven structural genes were found to be located in the same gene cluster. The order of the seven structural genes of the Paracoccus NADH-quinone oxidoreductase in the gene cluster is NQO7, NQO6, NQO5, NQO4, NQO2, NQO1, and NQO3. Upstream of the NQO7 gene, an open reading frame encoding a predicted polypeptide homologous to the UV repair enzyme A of Escherichia coli and Micrococcus lysodeikticus was detected. The 5'-terminus of the gene cluster carrying the Paracoccus NADH-quinone oxidoreductase was studied, and the possible promoter region is discussed. The NQO4 and NQO5 genes appear to code for the M(r) 48,000 and 21,000 polypeptides of the isolated Paracoccus NADH dehydrogenase complex [Yagi, T. (1986) Arch. Biochem. Biophys. 250, 302-311] on the basis of amino acid analyses and N-terminal protein sequence analyses. The antisera to the bovine complex I 49- and 30-kDa polypeptides cross-reacted with the Paracoccus 48- and 21-kDa subunits, respectively.

Amino Acid Sequence↗
PubMed1992

EPR and redox properties of Desulfovibrio vulgaris Miyazaki hydrogenase: comparison with the Ni-Fe enzyme from Desulfovibrio gigas.

We have carried out a detailed redox titration monitored by EPR on the hydrogenase from Desulfovibrio vulgaris Miyazaki. Typical 3Fe and nickel signals have been observed, which are very similar to those given by Desulfovibrio gigas hydrogenase in all the characteristic redox states of the enzyme. This confirms that D. vulgaris Miyazaki hydrogenase is a Ni-Fe enzyme closely related to that from D. gigas, as was recently proposed on the basis of sequence comparisons (Deckers, H.M., Wilson, F.R. and Voordouw, G. (1990) J. Gen. Microb. 136, 2021-2028).

Desulfovibrio vulgaris↗
PubMed1992

Salt tolerance and glycerol accumulation of a respiration-deficient mutant isolated from the petite-negative, salt-tolerant yeast Zygosaccharomyces rouxii.

A respiration-deficient (RD) mutant was isolated from the petite-negative, salt-tolerant yeast Zygosaccharomyces rouxii. One strain among sixteen glycerol-non-utilizing mutants exhibited vigorous liberation of CO2 but no uptake of O2. Furthermore, this strain lacked cytochrome aa3 and had a reduced level of cytochrome b. The few mitochondria found in cells of this strain contained few or no cristae. Salt tolerance and intracellular accumulation of glycerol by the RD strain were almost equal to that of the wild-type strain in media containing NaCl up to 2.5 M. In media with more than 3 M NaCl, the growth of the RD mutant was retarded and the intracellular accumulation of glycerol was depressed in spite of ample production.

Adaptation, Biological↗
PubMed1992

Three-component analysis of caloric nystagmus in humans.

Three-component analysis of caloric nystagmus, focusing on the horizontal, vertical, and torsional, using a computerized eye movement analysis system, was carried out in 10 normal human subjects. The caloric response was induced by cold stimulation to the right ear of the subjects in the supine and prone positions. In the supine position, the three components of nystagmus were toward the left (10 subjects), upward (eight subjects) or downward (two subjects), and clockwise (10 subjects). In the prone position, on the other hand, the three components were directed toward the right (10 subjects), downward (five subjects), upward (three subjects), and counterclockwise (10 subjects); there was no vertical direction in two subjects. These findings indicate that caloric stimulation activates the three semicircular canals simultaneously. Also the changes in the nystagmus direction in the supine and prone positions could be explained, at least partially, by the nonconvective component of caloric stimulation.

Adult↗
PubMed1992

Structural features of the 66-kDa subunit of the energy-transducing NADH-ubiquinone oxidoreductase (NDH-1) of Paracoccus denitrificans.

The structural gene of the Paracoccus denitrificans NADH-ubiquinone oxidoreductase encoding a homologue of the 75-kDa subunit of bovine complex I (NQO3) has been located and sequenced. It is located approximately 1 kbp downstream of the gene coding for the NADH-binding subunit (NQO1) [Xu, X., Matsuno-Yagi, A., and Yagi, T. (1991) Biochemistry 30, 6422-6428] and is composed of 2019 base pairs and codes for 673 amino acid residues with a calculated molecular weight of 73,159. The M(r) 66,000 polypeptide of the isolated Paracoccus NADH dehydrogenase complex is assigned the NQO3 designation on the basis of N-terminal protein sequence analysis, amino acid analysis, and immuno-cross-reactivity. The encoded protein contains a putative tetranuclear iron-sulfur cluster (probably cluster N4) and possibly a binuclear iron-sulfur cluster. An unidentified reading frame (URF3) which is composed of 396 base pairs and possibly codes for 132 amino acid residues was found between the NQO1 and NQO3 genes. When partial DNA sequencing of the regions downstream of the NQO3 gene was performed, sequences homologous to the mitochondrial ND-1, ND-5, and ND-2 gene products of bovine complex I were found, suggesting that the gene cluster carrying the Paracoccus NADH dehydrogenase complex contains not only structural genes encoding water-soluble subunits but also structural genes encoding hydrophobic subunits.

Amino Acid Sequence↗
PubMed1992

UV-induced base substitution mutations in a shuttle vector plasmid propagated in group C xeroderma pigmentosum cells.

To assess the contribution to mutagenesis of human DNA repair defects, the UV-irradiated shuttle vector plasmid pZ189 was propagated in fibroblasts derived from a xeroderma pigmentosum (XP) patient in DNA repair complementation group C. In comparison to results with DNA repair-proficient human cells (WI-38 VA13), UV-irradiated pZ189 propagated in the XP-C (XP4PA(SV)) cells showed fewer surviving plasmids and a higher frequency of mutated plasmids. Base sequence analysis of 67 mutated plasmids recovered from the XP-C cells revealed similar classes of point mutations and mutation spectrum, and a higher frequency of G:C to A:T transitions along with a lower frequency of transversions among plasmids with single or tandem mutations compared to plasmids recovered from the normal line. Most single-base substitution mutations (83%) occurred at G:C base pairs in which the 5'-adjacent base of the cytosine was thymine or cytosine. These results indicate that the DNA repair defects in XP-C, in comparison to data previously reported for XP-A, XP-D and XP-F, result in different UV survival and mutation frequency but in similar types of base substitution mutations.

Base Sequence↗
PubMed1992

Does the type of anomalous arrangement of pancreaticobiliary ducts influence the surgery and prognosis of choledochal cyst?

A new classification of the anomalous arrangement of pancreaticobiliary ducts (APBD) has been proposed following amendments and modificiations of the previous one. Fifty-one cases of choledochal cyst complicated with APBD were extensively examined and analyzed for clear visualization of the APBD system to make a standard classification. APBD were classified broadly into three types: type I, type II, and type III with their subtypes. Type I of APBD was seen in 18 (35.3%), type II in 11 (21.6%) and type III in 22 (43.1%) cases, respectively. A radical operation, including complete excision of the dilated biliary duct followed by reconstruction of the biliary tract was the surgical treatment of choice, because the reflux of the pancreatic juice into the biliary tract is prevented. However, a dilated common channel or accessory pancreatic duct, according to the new Komi type Ib, IIb, and IIIc3 of APBD, could be the cause of relapsing pancreatitis leading to chronic pancreatitis, due to the formation of a protein plug or pancreatic calculus in the dilated duct, even after this radical operation. In two complicated cases of type IIIc3 of APBD in choledochal cyst, we performed a pylorus-preserving pancreatoduodenectomy as one of the operative methods of choice. Long-term follow-up, more than decades, is essential to evaluate the results of surgical procedure for choledochal cyst, especially in those complicated cases with type Ib, IIb, and IIIc3 of APBD according to the new Komi's classification.

Adolescent↗
PubMed1992

Mice develop normally without tenascin.

Tenascin, an extracellular matrix protein, is expressed in an unusually restricted pattern during embryogenesis and has been implicated in a variety of morphogenetic phenomena. To directly assess the function of tenascin in vivo, we generated mutant mice in which the tenascin gene was nully disrupted by replacing it with the lacZ gene. In mutant mice, lacZ was expressed in place of tenascin, and no tenascin product was detected. Homozygous mutant mice were, however, obtained in accordance with Mendelian laws, and both females and males produced offspring normally. No anatomical or histological abnormalities were detected in any tissues, and no major changes were observed in distribution of fibronectin, laminin, collagen, and proteoglycan. The existence of these mutant mice, lacking tenascin yet phenotypically normal, casts doubt on the theory that tenascin plays and essential role in normal development.

Animals↗
PubMed1992

Metabolic activation of sennoside C in mice: synergistic action of anthrones.

Sennosides A and C directly injected into the caecum of mice showed equal purgative activity. Intracaecal administration reduced time to onset of diarrhoea induced by sennoside C from about 3 h after oral administration to about 24 min. At 2.3 h after oral administration of sennoside C, nearly equimolar amounts of aloe-emodin anthrone and rhein anthrone were detected in the large intestine of mice. The purgative effect of oral sennoside C could be reduced by pretreating mice with chloramphenicol. This was observed as a decreased formation of total anthrones in the large intestine. Both anthrones and an equimolar mixture of both anthrones directly injected into the caecum exerted a purgative effect, although the activity was lower for aloe-emodin anthrone. The intracaecal ED50 values were 54.5 (24.1-89.6), 11.4 (5.0-15.7) and 11.2 (6.1-14.6) mumol kg-1 for aloe-emodin anthrone, rhein anthrone and an equimolar mixture of both anthrones, respectively. We concluded that aloe-emodin anthrone and rhein anthrone, formed mainly by intraluminal bacterial action, are the true active metabolites of sennoside C in mice and that both anthrones synergistically exert their purgative effects on mice.

Animals↗
PubMed1992

Vestibular disorders following immune response of the endolymphatic sac in the guinea pig.

The effect of a direct antigen challenge to the endolymphatic sac on vestibular function was investigated in guinea pigs. Following keyhole limpet hemocyanin (KLH) challenge to the sac in systemically presensitized guinea pigs, caloric responses were examined in 18 animals on days 1, 7, 14, 21, and 28. Caloric responses were significantly suppressed in 13 animals by day 7; of these, 5 animals had recovered by day 14 and 8 animals had not yet recovered by day 28. The behavior of spontaneous nystagmus was examined every hour in 10 animals at intervals of 3 to 56 hours after sac challenge. Irritative spontaneous nystagmus preceding paralytic nystagmus appeared in 5 animals, for which the mean onset was 14.6 +/- 3.1 hours and the mean duration was 4.4 +/- 6.5 hours. Paralytic spontaneous nystagmus appeared in all animals, for which the mean onset time was 23.3 +/- 12.3 hours. Neither direct KLH primary challenge of the sac nor phosphate-buffered saline injection to the sac caused significant changes in the vestibular function. These results suggest that an immune response of the sac induces a vestibular disorder and may produce an attack of vertigo similar to that of Meniere's disease.

Aged↗
PubMed1992

Immunoelectron microscopy of carbonic anhydrase isozyme VI in rat submandibular gland: comparison with isozymes I and II.

Carbonic anhydrase (CA) was purified from the saliva of pilocarpine-treated rats by inhibitor-affinity chromatography, and its localization in the rat submandibular gland was studied by the indirect immunoperoxidase technique using a monoclonal antibody (MAb) raised against the enzyme. SDS-polyacrylamide gel electrophoresis of the CA VI gave three bands of 33, 39, and 42 KD. Enzyme digestion experiment showed that the 42 KD molecule was degraded into the 39 KD molecule and the 39 KD molecule into the 33 KD molecule. The cleavage of the 42 KD molecule was independent and that of the 39 KD molecule was dependent on endo-beta-N-acetylglucosaminidase F. The 42 KD molecule was detected in the CA purified from the pilocarpine-treated but not the untreated salivary gland. The MAb recognized all the three components of the enzyme. Immunostaining for CA VI was seen in the cytosol and secretory granules of serous acinar cells and in the duct luminal contents. Staining specific for erythrocyte CA (CA I and CA II) was observed in the cytosol of the epithelial cells of granular, striated, and excretory ducts. Among these duct cells, the agranular varieties in the granular and excretory ducts were essentially devoid of the immunoreactivity.

Animals↗
PubMed1992

Effect of captopril on isoproterenol-induced cardiac hypertrophy and polyamine contents.

It is well known that isoproterenol (ISO) a nonselective beta adrenoceptor agonist induces cardiac hypertrophy. It can be assumed that, in addition to its direct cardiac effect, ISO has a cardiac trophic effect via stimulation of the renin angiotensin system. Synthesis of polyamines is facilitated in cardiac hypertrophy and polyamine levels are rapidly elevated prior to an increase in heart weight. In the present study, we investigated whether captopril (30 mg/kg body weight, daily) could attenuate cardiac hypertrophy and elevation of cardiac polyamine levels in rats, which effects were elicited by a chronic (1- or 2-weeks) and repeated administration of a small dose (0.5 mg/kg body weight) of ISO. Cardiac hypertrophy was assessed by an increase in the wet weight and RNA content of the heart. Polyamines were analyzed by HPLC. Captopril alone did not affect either heart weight/body weight ratio or cardiac contents of polyamines and nucleic acids at the end of the second week. In isoproterenol-treated rats, the above parameters, except for putrescine content on day 14, were significantly increased on both day 7 and day 14. Captopril slightly attenuated ISO-induced cardiac hypertrophy and significantly prevented the ISO-evoked increase in the contents of RNA, spermidine, and spermine at the end of the second week. These results suggest that the ISO-evoked increase in cardiac polyamines was mediated, at least in part, by the renin angiotensin system, which was stimulated by ISO.

Animals↗
PubMed1992

Oxidative damage to the membrane of canine erythrocytes with inherited high Na, K-ATPase activity.

Oxidative damage to the membrane in canine erythrocytes with inherited high Na, K-ATPase activity (HK cells) was compared with that in normal canine cells (LK cells). When 30 mM beta-acetylphenylhydrazine (APH) was applied to HK and LK cells, lipid peroxidation and hemoglobin denaturation occurred. Lipid peroxidation determined from malondialdehyde (MDA) formation was significantly lower in HK than in LK cells so far as endogenous glutathione (GSH) concentration was maintained at appropriate levels. With the depletion of GSH, MDA formation was accelerated and difference between HK and LK cells was not significant. Denatured hemoglobin bound to the membrane protein was less in HK than in LK cells. During incubation with APH, osmotic fragility increased markedly in LK cells, while HK cells showed very little change. The amounts of total lipid, total and free cholesterol, glycolipid, phospholipid and fatty acids were essentially the same in both cell types. Fatty acid compositions showed very small differences. The membrane of HK cells thus appear to have greater protection against oxidative damage induced by APH, owing to the presence of excess GSH in HK cells. The capability of HK cells to withstand oxidative damage would not be due to differences in membrane lipid compositions.

Animals↗