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K Hotta

Publications and source records attributed to K Hotta.

At least 217 records · Page 12Linked to original sources
PubMed1990

Extraction method for preparing pyridylamino sugar derivatives and application to porcine gastric mucus glycoprotein analysis.

For the sensitive detection of free sugars and oligosaccharides, the use of their pyridylamino derivatives has now found general acceptance. To remove excess 2-aminopyridine from this derivative in a reaction mixture, gel filtration and ion-exchange chromatography were conducted. It was found in the present study that contaminated 2-aminopyridine could be selectively removed from the reaction mixture by adjusting the pH with saturated sodium bicarbonate at above 8.5 followed by extraction with benzene. By using this method, fewer purification steps and less time are required, with minimum loss of pyridylamino sugar derivatives.

Amino Sugars↗
PubMed1990

Coding region structure of interleukin-8 gene of human lung giant cell carcinoma LU65C cells that produce LUCT/interleukin-8: homogeneity in interleukin-8 genes.

A 1.9-kb fragment containing an interleukin-8 (IL-8) coding region was amplified by the polymerase chain reaction (PCR) from the genomic DNA of human lung giant cell carcinoma LU65C cells that produce LUCT/IL-8 with N-terminal sequence of AVLPR. The coding region was found to consist of 4 exons and 3 introns as identical as that of the gene of MDNCF/IL-8 lacking N-terminal AVLPR. PCR using genomic DNAs from human polymorphonuclear leukocytes and mononuclear cells also provided the same 1.9-kb fragment as that from LU65C genomic DNA. Thus, it seems likely that human cells possess IL-8 genes with the homogeneous coding region so that they may first produce the same mature protein with N-terminal AVLPR (= LUCT) which was then truncated.

Amino Acid Sequence↗
PubMed1990

[Effects of acid secretagogues on rat gastric mucus glycoprotein content and gastric mucosal resistance].

In our previous reports, low dose acid secretagogues caused increase in corpus mucus glycoprotein content in rats. This increase was not due to the direct action of protons. The present study was conducted to determine whether this increase has a mucosal function or not Rats were given histamine (0.8 mg/kg) intraperitoneally or tetragastrin (12 micrograms/kg) subcutaneously. One hour following the acid secretagogues administration, the animals were given 1 ml of 30, 40 or 50% ethanol orally and then sacrificed after one hour. Gastric mucus glycoproteins were isolated from the corpus region of stomach. The following results were obtained: 1) Histamine prevented the gastric mucosal damage and the decrease of corpus mucus glycoprotein content induced by 40% ethanol ingestion. 2) Tetragastrin prevented the gastric mucosal damage induced by 30 approximately 50% ethanol ingestion and the decrease of corpus mucus glycoprotein content induced by 40 approximately 50% ethanol ingestion. Based on these results, the increase of corpus mucus glycoprotein content induced by acid secretagogues has a mucosal function. Moreover, tetragastrin strengthened the mucosal defence together with acid secretion.

Animals↗
PubMed1989

Types of oligosaccharide sulphation, depending on mucus glycoprotein source, corpus or antral, in rat stomach.

Radiolabelled mucus glycoprotein was obtained from tissue and a culture medium each of the corpus and antrum of rat stomach incubated with [35S]sulphate in vitro. Gel-filtration analysis of oligosaccharides liberated by alkaline-borohydride treatment from glycoproteins indicated that 35S-labelled oligosaccharides from the corpus vary considerably with respect to chain length whereas those from antral mucus glycoprotein are composed of small oligosaccharides. Examination of the reduced radiolabelled products obtained by HNO2 cleavage of the hydrazine-treated oligosaccharides indicated sulphate esters of N-acetylglucosamine to be present at three locations on a carbohydrate unit: [35S]sulphated monosaccharide (2,5-anhydromannitol 6-sulphate), [35S]sulphated disaccharide [galactosyl(beta 1-4)-2,5-anhydromannitol 6-sulphate] and [35S]sulphated trisaccharide [fucosyl(alpha 1-2)-galactosyl(beta 1-4)-2,5-anhydromannitol 6-sulphate]. Sulphated disaccharide and trisaccharide, possibly originating from the N-acetyl-lactosamine and fucosyl-N-acetyl-lactosamine sequences respectively, were detected in the corpus, especially as large oligosaccharides, but were present in the antrum in only very small amounts. The sulphated monosaccharide, however, most probably originating from 6-sulphated N-acetylglucosamine residues at non-reducing termini, was present in all oligosaccharide fractions in both the corpus and antrum.

Animals↗
PubMed1989

Mechanism of cerebral vasospasm--contractile proteins in smooth muscle of bovine cerebral artery.

Understanding of the pathogenesis of cerebral vasospasm requires basic study of the contraction mechanism of cerebral arteries. In this study, the morphological and biochemical properties of actomyosin from bovine cerebral arteries were examined. Arrays of thick and thin filaments were clearly seen on electron micrographs of a cross section of a muscle strip stretched to 1.5 times its normal length in Krebs-Ringer solution. The diameters of the thick and thin filaments were 110.0 +/- 19.9 A and 51.0 +/- 8.0 A, respectively. The average ratio of thick to thin filaments was about 1:15 to 1:16. The gel pattern of Ca2+-sensitive actomyosin extracted from bovine cerebral arteries revealed the presence of myosin, actin, and tropomyosin, but not skeletal troponin. The Mg-ATPase activity of actomyosin was greatly enhanced in the presence of Ca2+. Rapid superprecipitation occurred after the clearing phase, when 1 mM Mg-ATP was added to a suspension of actomyosin with 10(-5) M Ca2+. This superprecipitation did not occur with a lower Ca2+ concentration of 10(-8) M. Intracellular free Ca2+ appears to play a crucial role in the regulation of contraction and relaxation of cerebral arterial smooth muscle.

Actins↗
PubMed1989

Pathogenesis of water-immersion stress-induced gastric ulcers in rats with renal failure.

Rats with or without renal failure, produced by uranyl acetate, were subjected to water-immersion stress for 6 h. The severity of stress-induced gastric ulcers in the renal failure group was significantly higher than that in the control group. The intragastric pH did not significantly differ between the two groups. Transmucosal electrical potential difference, gastric mucosal blood flow, and gastric mucosal hexosamine content in the renal failure group were significantly lower than in the control group. These results suggest that decreases in defensive factors, rather than an increase in an aggressive factor, may be more closely involved in the development of acute gastric ulcers in rats with renal failure.

Acute Kidney Injury↗
PubMed1989

Nucleotide sequence of the macromomycin apoprotein gene and its expression in Streptomyces macromomyceticus.

A 1.6 kb Sph I-Sac I DNA fragment from Streptomyces macromomyceticus, expected to include the macromomycin (MCM) apoprotein gene, was sequenced. The fragment (1,556 bp) was found to include a putative promoter, an ORF directing pre-apoprotein which should be split into the leader peptide (Met1 to Gly32) and the MCM apoprotein (Ala33 to Ala144), and a putative terminator. The amino acid sequence deduced from the base sequence of the DNA is consistent with the amino acid sequence previously determined by the Edman degradation and other procedures applied to the protein, except base sequence AAC coding for Asn was found rather than Asp111 previously reported. The GC content of the 3rd letters throughout the ORF was 92% in contrast to the sum of the first and the second letters, 62%. There was a low GC content stretch of 20 bp (30% GC) at about 120 bp upstream of the ORF. The Pst I-Sph I 620 bp fragment including the low GC content stretch showed promoter activity when subcloned in a promoter probe vector. About 700 nucleotides long mRNA, which is long enough to span the ORF and the bordering regions, was identified using the Northern blot analysis. A primer extension experiment showed that the transcriptional starting point was A at 89 bp upstream of the ORF. Dot blot analysis of expression of MCM apoprotein gene indicated that the gene was expressed nearly constitutively, while production of holo MCM (the complex consisting of MCM apoprotein and a specific chromophore) depended greatly on culture conditions.

Amino Acid Sequence↗
PubMed1989

Biosynthetic similarity between Streptomyces tenjimariensis and Micromonospora olivasterospora which produce fortimicin-group antibiotics.

The profile of bioconversion products of istamycin (IS) components by a blocked IS mutant of Streptomyces tenjimariensis that lost IS-productivity suggested a possible biosynthetic pathway of IS similar to that of fortimicin (FT) by Micromonospora olivasterospora. Both organisms are resistant to the antibiotics produced by each other. Based on these similarities, they were examined for their capability to convert an FT-intermediate (FT-B) and IS-intermediates (IS-A0 and -B0) through their biosynthetic pathways. S. tenjimariensis formed 1-epi-FT-B, 2''-N-formimidoyl-FT-A (= dactimicin) and 1-epidactimicin (a new antibiotic) from FT-B. On the other hand, M. olivasterospora converted IS-A0 and -B0 to 2''-N-formimidoyl-IS-A (= IS-A3) and -B (= IS-B3), respectively. Thus, the similarity in antibiotic biosynthesis was confirmed between these FT-group antibiotic-producing organisms. It was also found that the major fermentation product of M. olivasterospora is not FT-A (astromicin) but dactimicin.

Aminoglycosides↗
PubMed1989

Effect of the proton pump inhibitor, NC-1300, on gastric mucus secretion in rats.

The effects of NC-1300 on gastric acid and mucus glycoprotein secretion were investigated in pylorus-ligated (4 h) rats. NC-1300 (30 mg/kg, intraduodenally) significantly inhibited gastric acid concentration more than 90%. The agent did not affect the total mucus glycoprotein output in the gastric juice, but caused by about 1.5 times denser mucus glycoprotein secretion than that in the control group. The amount of mucus glycoprotein in the mucous gel layer increased by about 1.4 times with this agent. Thus, NC-1300 not only inhibits acid secretion but also promotes mucus secretion, and this may explain its ability to protect the stomach against necrotizing agents.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1988

Release of oligosaccharides possessing reducing-end N-acetylgalactosamine from mucus glycoprotein in Streptomyces sp. OH-11242 culture medium through action of endo-type glycosidase.

A crude enzyme preparation from a culture medium of Streptomyces sp. OH-11242 contained endo-alpha-N-acetylgalactosaminidase activity. The activity could be induced by the addition of purified porcine gastric mucin to the culture medium. Oligosaccharides corresponding to approximately 2-14 glucose units were detected in the culture medium and also in an incubated reaction mixture of crude enzyme preparation and mucus glycoprotein. The resulting product with N-acetylgalactosamine at the reducing terminal implied the presence of a new type of endo-glycosidase liberating not only Gal beta 1-3GalNAc but also other larger oligosaccharides by hydrolysis of the O-glycosidic linkage between GalNAc and Ser (Thr).

Animals↗
PubMed1988

Detection of UDP-N-acetylgalactosamine-oligosaccharide N-acetylgalactosaminyltransferase activity in rat stomach and human serum by high-performance liquid chromatography.

The enzymatic transfer of the sugar portion from UDP-N-acetylgalactosamine to pyridylamino (PA) lacto-N-fucopentaose I (Fuc alpha 1-2Gal beta 1-3GlcNAc beta 1-4Glc-PA) was detected by high-performance liquid chromatography. Separation of the fluorescent product from the fluorescence-labeled acceptor was achieved within 10 min by reversed-phase high-performance liquid chromatography. Rat stomach enzyme activity was detected in the microsomal fraction from antrum but not corpus. Ohara et al. (1986, Comp. Biochem. Physiol. 83B, 273-275) reported that the N-acetylgalactosamine content in antrum mucin was greater than that in corpus mucin and antrum mucin had strong blood group A activity. The prominent asymmetrical distribution of the enzyme detected here well supports these findings. The elution position of the fluorescent product was the same as that of the product formed by the action of type A human serum toward the acceptor. Its hydrolysis by alpha-N-acetylgalactosaminidase yielded the acceptor. It is thus evident that the detected enzyme is the same as that producing the blood group A structure.

Animals↗
PubMed1988

Comparative study of chicken ovalbumin subfractions having different carbohydrate chain from each other by high performance anion exchange chromatography.

1. Ovalbumin was fractionated to six fractions according to their phosphate content by high performance anion exchange chromatography. 2. This method was applied to analyze the phosphate content of ovalbumin subfractions having different carbohydrate chain from each other which were prepared by concanavalin A/Sepharose chromatography from oviduct slices incubated with [2-3H]mannose. 3. Most biosynthetic intermediates bearing a carbohydrate chain of Man8 or 9 GlcNAc2 was not phosphorylated while other fractions bearing differently processed carbohydrate chains such as Man5 or 6 GlcNAc2 or hybrid type carbohydrate chain was phosphorylated at their peptide portion.

Animals↗
PubMed1988

Detection of human leukocyte interferon-alpha A and -alpha 2 genes in genomic DNAs by the use of deoxyoctadecyloligonucleotide probes.

Two deoxyoctadecyloligonucleotides complementary to the sequence spanning a single base substitution between human leukocyte interferon (HuIFN) alpha A and alpha 2 genes were efficiently used as probes to distinguish between HuIFN-alpha A and -alpha 2 genes. At 37 degrees C or 42 degrees C under aqueous conditions (0.9 M NaCl), hybridization between both probes and the alpha A and alpha 2 genes without any mismatch was strong, whereas the hybridization with one base mismatch (alpha A probe-alpha 2 gene and alpha 2 probe-alpha A gene) was very weak or negligible. Because the single base substitution of G in the alpha 2 gene for A in the alpha A gene provides an extra HinfI site in the alpha 2 gene at the center of the sequence hybridizing to the alpha 2 probe, digestion with HinfI restriction endonuclease caused complete loss of the hybridization between the alpha 2 probe and the alpha 2 gene. PvuII digestion provides 298-bp fragments hybridizing to the probes only from the alpha A and alpha 2 genes among the known HuIFN-alpha genes. Thus, with the use of these oligonucleotide probes in combination with PvuII and PvuII-HinfI restriction endonuclease digestion, the existence of the sequences corresponding to both IFN-alpha A and IFN-alpha 2 genes in human genomic DNAs was demonstrated. The results also surprisingly indicate that these genes, formerly considered alleles because of their essential identity (1 base pair difference in the coding sequence), are not likely to be alleles, but represent closely related distinct genes.

DNA Restriction Enzymes↗
PubMed1988

Two types of rat gastric mucus glycoprotein subunits.

Gastric mucus glycoproteins were extracted with 2% Triton X-100 from rat gastric corpus and antrum and purified by CsCl equilibrium centrifugation. Corpus mucus glycoproteins were degraded into what appeared to be two "subunits" (Mw 4.4 x 10(5) and 6 x 10(6)) by the reduction of disulfide bonds. Papain digestion of the latter produced glycopeptides with a molecular weight of approximately 4.4 x 10(5). This type of subunit had carbohydrate chains with about 9 sugars attached to every 2 amino acid residues. Papain digestion of the former type of subunit revealed no change in the elution profile on Bio-Gel A-15m. This type of subunit had carbohydrate chains with 17-19 sugars attached to every 3 amino acid residues. The subunit of antral mucus glycoproteins was essentially the same as the former type of corpus subunits in molecular weight (Mw 4.4 x 10(5)) and average oligosaccharide chain length. These results suggest that there are two distinct types of mucus glycoprotein subunits in rat stomach.

Animals↗
PubMed1988

Mucus glycoprotein and mucosal protection.

For assessing the participation of mucus glycoproteins in the cytoprotective process, mucus glycoprotein content in the rat gastric mucosa was measured after treatment with 70% ethanol with or without prostaglandin (PG) E derivatives or 20% ethanol pretreatment. Oral administration of two synthetic PGE derivatives did not cause any significant changes in mucus glycoprotein content. Seventy percent ethanol administration caused marked reduction in mucus glycoprotein content (about 50% of control) as well as severe gastric mucosal damage. Treatment with two PGE derivatives (10-100 micrograms/kg) prior to 70% ethanol administration markedly inhibited the gross mucosal lesion, whereas the glycoprotein content under these conditions was significantly less than that in the untreated control group (ranging from 67-88% of control). Pretreatment with 20% ethanol markedly inhibited the gross mucosal damage caused by 70% ethanol dosing but the inhibition in the reduction of mucus glycoprotein content was restricted to about 80% of the untreated controls. In summary, cytoprotection induced by PG was not accompanied by entire conservation of intramucosal mucus glycoprotein in the gastric mucosa.

Alprostadil↗
PubMed1988

Changes of rat gastric mucus glycoproteins in cytoprotection: influences of prostaglandin derivatives.

The effects of two synthetic prostaglandin E derivatives on mucus glycoproteins in the stomachs of rats were evaluated. Neither derivative caused change in mucus glycoprotein content in the gastric corpus or antrum, but both increased the biosynthetic activity of mucus glycoproteins in these regions (about 15-30%). Furthermore, the effects of the pretreatment of these derivatives on conserving mucus glycoproteins in ethanol-induced gastric lesions were examined. Treatment with these derivatives 60 min prior to 70% ethanol administration markedly inhibits the decrease in gastric mucus glycoprotein content caused by 70% ethanol. But the glycoprotein content under these pretreatment conditions was significantly less (12-19%) than that in the control group without any drug treatment.

Alprostadil↗
PubMed1988

Effects of cimetidine on prostanoid production in the gastric corpus specimens from rats.

In order to examine the effect of cimetidine on the production of prostanoids in the stomach mucosa, the amounts of prostaglandin (PG) E2, F1 alpha and thromboxane (TX) B2 were determined after the specimens from the rat stomach corpus were incubated in the presence of cimetidine. Cimetidine significantly stimulated the production of PGE2 in the specimens at a concentration of 10 microM, but did not significantly affect the production of PGF1 alpha and TXB2 at concentrations of 1 to 100 microM.

Animals↗