PubMed Health⌕ Search

Biomedical subjects

Hiroyuki Yano

Publications and source records attributed to Hiroyuki Yano.

15 recordsLinked to original sources
PubMed2006

Disulfide proteome yields a detailed understanding of redox regulations: a model study of thioredoxin-linked reactions in seed germination.

Accumulating evidence suggests that redox regulations play important roles in a broad spectrum of biological processes. Recently, Yano et al. developed a disulfide proteome technique that comprehensively visualizes redox change in proteins. In this paper, using the disulfide proteome, we examined rice bran and identified fragments of embryo-specific protein and dienelactone hydrolase as putative targets of thioredoxin. Also, monitoring of the endogenous and recombinant effects of thioredoxin on rice bran proteins and supporting in vivo observations propose a mechanism of redox regulation in seed germination, in which thioredoxin activates cysteine protease with a concurrent unfolding of its substrate, the embryo-specific protein. Our findings suggest that thioredoxin controls the lifetime of specific proteins effectively by regulating the redox reactions coordinately. The model study demonstrates that the disulfide proteome technique is useful not only for identifying targets of thioredoxin, but also for clarify the detailed mechanism of redox regulation.

Amino Acid Sequence↗
PubMed2006

Update and challenges on proteomics in rice.

Rice is not only an important agricultural resource but also a model plant for biological research. Our previous review highlighted different aspects of the construction of rice proteome database, cataloguing rice proteins of different tissues and organelle, differential proteomics using 2-DE and functional characterization of some of the proteins identified (Komatsu, S., Tanaka, N., Proteomics 2005, 5, 938-949). In this review, the powerfulness and weaknesses of proteomic technologies as a whole and limitations of the currently used techniques in rice proteomics are discussed. The information obtained from these techniques regarding proteins modification, protein-protein interaction and the development of new methods for differential proteomics will aid in deciphering more precisely the functions of known and/or unknown proteins in rice.

Cluster Analysis↗
PubMed2005

Distinct functional units of the Golgi complex in Drosophila cells.

A striking variety of glycosylation occur in the Golgi complex in a protein-specific manner, but how this diversity and specificity are achieved remains unclear. Here we show that stacked fragments (units) of the Golgi complex dispersed in Drosophila imaginal disk cells are functionally diverse. The UDP-sugar transporter FRINGE-CONNECTION (FRC) is localized to a subset of the Golgi units distinct from those harboring SULFATELESS (SFL), which modifies glucosaminoglycans (GAGs), and from those harboring the protease RHOMBOID (RHO), which processes the glycoprotein SPITZ (SPI). Whereas the glycosylation and function of NOTCH are affected in imaginal disks of frc mutants, those of SPI and of GAG core proteins are not, even though FRC transports a broad range of glycosylation substrates, suggesting that Golgi units containing FRC and those containing SFL or RHO are functionally separable. Distinct Golgi units containing FRC and RHO in embryos could also be separated biochemically by immunoisolation techniques. We also show that Tn-antigen glycan is localized only in a subset of the Golgi units distributed basally in a polarized cell. We propose that the different localizations among distinct Golgi units of molecules involved in glycosylation underlie the diversity of glycan modification.

Animals↗
PubMed2005

Nucleolonema as a fundamental substructure of the nucleolus.

The nucleolus is the most obvious structure in the eukaryotic nucleus. It is known to be a ribosome-producing apparatus where ribosomal (r) DNA is transcribed and the primary rRNA transcripts are processed to produce three of the four rRNA species. Electron microscopy has shown that the nucleolus consists of three major components, a dense fibrillar component (DFC), a granular component (GC) and a fibrillar center (FC). The DFC and FCs are integrated into a fundamental nucleolar substructure called the nucleolonema. The DFC corresponds to the matrix of the nucleolonema, and the FC is an electron microscopic counterpart of argyrophobic lacunae localized in the nucleolonema. The spherical FCs are intermittently arranged along the length of the nucleolonema in actively growing cells but are fused with each other to form tubular FCs when rDNA transcription is hampered. The RNase-gold complex does not bind to the FC but to the DFC and the GC, suggesting that rDNA transcription does not occur in the FC although both fluorescence in situ hybridization (FISH) and electron microscopic in situ hybridization reveal that the rDNA is specifically localized in the FCs. Immunogold-labeling after bromo-UTP (BrUTP) incorporation shows that rDNA transcription takes place in the boundary region between the FC and the DFC, and primary rRNA transcripts are expected to be processed outward within the DFC. Data have accumulated suggesting that the nucleolonema is a fundamental substructure of the nucleolus, and its skeleton is the tandem arrangement of the FCs, which are resting harbors or storages of rDNA. This paper proposes that the transversal structural organization of the nucleolonema is centrifugally built up by several structural and functional domains: condensed and/or loosened rDNA, rDNA transcription zone, and transcript processing and ribosome assembly zones.

Cell Nucleolus↗
PubMed2003

Fluorescent labeling of disulfide proteins on 2D gel for screening allergens: a preliminary study.

An experimental protocol was established to detect disulfide proteins as fluorescent spots on 2D gel. In summary, free sulfhydryl groups in a protein mixture were capped with nonfluorescent iodoacetamide, followed by chemical reduction of disulfide bonds, and labeling of newly exposed sulfhydryl groups with the fluorescent probe, monobromobimane. Disulfide proteins were detectable as fluorescent spots under the UV lamp. As accumulating evidence suggests that disulfide bonds are responsible for the allergenicity of many proteins, we sought to use this protocol to find new allergens. In a model experiment using soybean trypsin inhibitor, a well-known allergen with disulfide bonds, and myoglobin, which has a free sulfhydryl group, only the former was labeled with fluorescence. Application of the protocol to mite and pollen extracts facilitated detection of known allergens or putative allergens exhibiting sequence similarities to known allergens. In this note, we report the protocol as a complementary tool for screening allergens, which is now solely dependent on immunological recognition.

Allergens↗
PubMed2003

Enhancement by interleukin-1 beta of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats: a possible mechanism for Helicobacter pylori-associated gastric carcinogenesis.

The effect of prolonged administration of the cytokine interleukin (IL)-1beta on gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was examined in Wistar rats. In addition, we examined the effects on the proliferating cell nuclear antigen (PCNA) labeling index and the hepatocyte growth factor (HGF) immunoreactivity of the gastric mucosa. The rats received intraperitoneal injections of 0.1 or 0.3 microg/kg body weight of IL-1beta every other day after oral treatment with MNNG for 25 weeks. Long-term administration of IL-1beta at high dose, but not at low dose, significantly increased the incidence of gastric cancer in week 52. Administration of IL-1beta at high dose also significantly increased the labeling index and the HGF immunoreactivity of the gastric antral mucosa, and induced inflammatory cell infiltration and glandular atrophy of the gastric mucosa. Because IL-1beta production in the gastric mucosa is increased in patients with Helicobacter pylori-associated gastritis and eradiation of the organism significantly decreases the IL-1beta production, these findings suggest that Helicobacter pylori-associated gastric carcinogenesis may be in part mediated through IL-1beta.

Adenocarcinoma↗
PubMed2003

Suppression by iron chelator phenanthroline of sodium chloride-enhanced gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats.

The effect of prolonged administration of iron chelator phenanthroline on sodium chloride-enhanced gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine, and the labeling and apoptotic indices in the gastric cancers was investigated in Wistar rats. After 25 weeks of carcinogen treatment, the rats were given chow pellets containing 10% sodium chloride and intraperitoneal injections of phenanthroline at doses of 15 or 30 mg/kg body weight every other day. At week 52, feeding of sodium chloride significantly increased the incidence of gastric cancers, as compared with the control group. Prolonged injections of phenanthroline at both doses significantly reduced the incidence of gastric cancers, which was enhanced by oral supplementation with sodium chloride. Phenanthroline at both doses significantly decreased the labeling index of gastric cancers, which was enhanced by sodium chloride, and significantly increased the apoptotic index of gastric cancers, which was lowered by sodium chloride. In vitro examination using electron spin resonance revealed that sodium chloride promotes the production of hydroxyl radical during Fe(2+) oxidation by Fenton's reaction. These findings suggest that enhancement by sodium chloride of gastric carcinogenesis may be mediated by hydroxyl radicals.

Adenocarcinoma↗
PubMed2003

Suppression by nimesulide of bombesin-enhanced peritoneal metastasis of intestinal adenocarcinomas induced by azoxymethane in Wistar rats.

The effects of the cyclooxygenase (COX)-2 inhibitor nimesulide on bombesin-enhanced peritoneal metastasis of azoxymethane (AOM)-induced intestinal adenocarcinomas were investigated in male Wistar rats. From the beginning of the study, the rats were given 10 weekly s.c. injections of AOM (7.4 mg/kg body weight) and s.c. injections of bombesin (40 microg/kg body weight) every other day. From week 16, the rats were given chow pellets containing 200 ppm or 400 ppm nimesulide ad libitum until termination of the study at week 45. Nimesulide at the higher dose significantly decreased the incidence of bombesin-enhanced metastasis to the peritoneum at week 45, although its administration had little or no effect on the location, histologic type, depth of involvement or infiltrating growth patterns of the tumors. Nimesulide also significantly decreased the incidence of bombesin-enhanced lymphatic vessel invasion by adenocarcinomas. Finally, it also inhibited bombesin-induced matrix metalloproteinase (MMP)-9 and pro-MMP-9 inductions. Our findings indicate that nimesulide may inhibit cancer metastasis through inhibition of pro-MMP-9 and MMP-9 inductions.

Adenocarcinoma↗
PubMed2002

Disulfide proteome in the analysis of protein function and structure.

Many proteins undergo post-translational modification via well defined mechanisms such as acetylation, phosphorylation and glycosylation and thereby control a spectrum of biochemical processes. A growing body of evidence suggests that the reversible reduction of disulfide bonds also alters the structure and activity of proteins. Thioredoxin, a ubiquitous 12 kDa protein with a catalytically active disulfide active site (Cys-Gly-Pro-Cys), plays a central role in controlling the redox status of disulfide bonds in proteins that regulate a range of processes. Included are photosynthesis, seed germination, transcription, cell division, radical scavenging and detoxification. The ability to identify unknown functions of proteins of all types has been advanced by the emerging field of functional proteomics. In this brief review, we introduce the disulfide proteome as a tool that complements other methods for the comprehensive analysis of proteins. In so doing, the usefulness of applying this method for both in vitro and in vivo analyses is discussed for thioredoxin and other disulfide proteins, especially those occurring in plants.

Allergens↗
PubMed2002

Polaprezinc attenuates Helicobacter pylori-associated gastritis in Mongolian gerbils.

BACKGROUND: The ammonia-monochloramine system plays an important role in Helicobacter pylori-associated gastric mucosal injury. Polaprezinc, a new antiulcer agent, has a scavenging action against monochloramine. The aim of the experiment was to investigate the inhibitory effects of polaprezinc on the H. pylori-induced gastritis in Mongolian gerbils. MATERIALS AND METHODS: Mongolian gerbils fasting for 24 hours were orally given culture broth containing 2-4 x 10(8) colony-forming units of H. pylori ATCC 43054 per milliliter. From 4 hours after inoculation until the end of the experiment, gerbils were given chow pellets with or without 0.02% polaprezinc. All gerbils were killed 12 weeks later. The grades of H. pylori density and histologic features of gastritis were evaluated in accordance with the Updated Sydney System. The scavenging effect of polaprezinc on monochloramine was investigated spectrophotometrically. RESULTS: Polaprezinc had little or no influence on the H. pylori density in both pyloric and fundic mucosae. However, it significantly attenuated the development of polymorphonuclear neutrophil activity, mononuclear infiltration, and surface epithelial erosion in both pyloric and fundic mucosae compared with those of the control group. H. pylori inoculation significantly increased the heights of both pyloric and fundic mucosae (mainly due to the increased height of foveolar hyperplasia), but polaprezinc inhibited the increase of mucosal thickness in both pyloric and fundic mucasae. No intestinal metaplasia was detected in this study. Spectrophotometric examination revealed that polaprezinc scavenged monochloramine. CONCLUSIONS: Polaprezinc inhibited the development of H. pylori-induced gastritis through its scavenging action against monochloramine.

Animals↗
PubMed2002

Combination of electron microscopic in situ hybridization and anti-DNA antibody labelling reveals a peculiar arrangement of ribosomal DNA in the fibrillar centres of the plant cell nucleolus.

The fibrillar centres (FCs) in the nucleoli of Allium cepa usually contained compact dense chromatin, which was always surrounded with light fibrous material (LFM). Distribution of 18S ribosomal DNA (rDNA) in the FCs was examined by in situ hybridization at the light and electron microscopic levels and the results were compared with those obtained by immunogold labelling with anti-DNA antibodies. Anti-DNA antibodies heavily labelled the dense chromatin of the FCs but scarcely labelled the LFM. However, electron microscopic in situ hybridization using the 18S rDNA probe showed that the label in the dense chromatin was extremely weak compared with that obtained by the anti-DNA antibody labelling: the specific label with anti-DNA antibodies of the dense chromatin was about 15 times as much as that of the LFM, whereas the specific label with in situ hybridization in the dense chromatin was only about 1.7 times higher than in the LFM. These results suggest that the rDNA encoding rRNA is preferentially released from the dense chromatin and that non-transcribed intergenic spacers remain in the dense chromatin as the anchoring sites of rDNA.

Antibodies↗
PubMedDate not supplied

Prevention by bovine milk against Helicobacter pylori-associated atrophic gastritis through its adherence inhibition.

BACKGROUND/AIMS: The effects of Helicobacter pylori infection on the development of atrophic gastritis and intestinal metaplasia in relation to lifestyle and diet and the effect of the bovine milk on H. pylori adherence to gastric antral mucosa were investigated. METHODOLOGY: H. pylori infection was investigated in 63 patients without endoscopic evidence of gastroduodenal disease. Presence of H. pylori infection was assessed by culture and histologic examination of antral and corpus biopsy samples. Grades of atrophic gastritis and intestinal metaplasia were judged with chromoendoscopy (Congo red-methylene blue test). Adherence of H. pylori was evaluated with scanning electron microscopic examination of antral mucosa in Mongolian gerbils. RESULTS: Cross-sectional analysis of lifestyle and diet showed that a high intake of bovine milk was significantly related to prevention of H. pylori infection and the developments of atrophic gastritis and intestinal metaplasia. H. pylori adherence to the gastric mucosa was inhibited by bovine milk in a dose-dependent manner. CONCLUSIONS: Bovine milk prevents the development of atrophic gastritis and intestinal metaplasia through its defense mechanisms against the attachment of H. pylori to the gastric mucosa.

Animals↗
PubMedDate not supplied

Helicobacter pylori infection as a risk factor for gastric ulceration.

BACKGROUND/AIMS: Recent reports have shown that Helicobacter pylori infection is closely related to pathogenesis of gastric ulcers. But there have been no reports on the prospective follow-up study of the patients with H. pylori infection to determine whether H. pylori infection puts patients at high risk of developing gastric ulcers. METHODOLOGY: Fifty-two patients with H. pylori infection and 34 patients without H. pylori infection, who were found endoscopically not to have localized lesions in the esophagus, stomach, or duodenum, underwent endoscopy follow-ups during the average observation period of 52 months. During each endoscopy, biopsy specimens were obtained from the antrum and the middle corpus. The grade of atrophy and intestinal metaplasia in the biopsy specimens were assessed histologically in accordance with the guidelines of the Updated Sydney System. RESULTS: Gastric ulcers developed in 8 (15%) of 52 patients with H. pylori infection, but not in patients without H. pylori infection: the difference was statistically significant (P<0.05). The development and the location of gastric ulcers was correlated to the development or progression of mucosal atrophy. In 8 (38%) of 21 patients in whom mucosal atrophy developed or progressed, gastric ulcers developed, but no ulcers developed in 31 patients without development or progression of gastric mucosal atrophy. Gastric ulcers developed in the gastric mucosa in which atrophy developed or progressed. CONCLUSIONS: H. pylori infection increases the risk for development of gastric ulcers and gastric ulcers developed through the progression of H. pylori-associated gastric mucosal atrophy.

Adult↗