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181.
Uozumi N Gao C Yoshioka T Nakano M Moriwaki K Nakagawa T Masuda T Tanabe M Miyoshi E 《Journal of proteome research》2010,9(12):6345-6353
Carbohydrate antigen 19-9 (CA19-9) is a well-known tumor marker for pancreatic cancer. Although the CA19-9 level is measured using anti-sialyl Lewis A antibodies, it remains unknown which molecules carry CA19-9 other than mucins. Here we report the identification and characterization of a novel type of CA19-9 carrier, BGM (bile globular membrane), which is thought to exist in normal bile and to be secreted into sera of patients with pancreatic cancer. We purified the BGM from bile juice using a β-casein column because surface plasmon resonance analysis could detect such carrier vesicles binding to β-casein in sera of patients with pancreatic cancer. We identified characteristic molecules for BGM such as AHNAK (desmoykoin) and a novel golgin family member, CABIN (CAsein Binding domain integral protein with golgIN motif) by mass spectrometry analysis. BGM was detected in the sera of patients with pancreatic cancer as well as athymic mice with transplanted pancreatic cancer cells. Down regulation of CABIN inhibited the secretion of CA19-9 on BGM in pancreatic cancer cell lines. We measured and visualized BGM in sera of patients with cancer. Thus, BGM might be another CA19-9 carrier (glyco-lipids on membrane vesicles) other than mucins and could be applied to the diagnosis of pancreatic cancer. 相似文献
182.
Exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine by increasing antioxidant enzyme activities 总被引:3,自引:0,他引:3
Hoque MA Okuma E Banu MN Nakamura Y Shimoishi Y Murata Y 《Journal of plant physiology》2007,164(5):553-561
Proline and betaine accumulate in plant cells under environmental stresses including salt stress. Here, we investigated effects of proline and betaine on the growth and activities of antioxidant enzymes in tobacco Bright Yellow-2 (BY-2) culture cells in suspension under salt stress. Both proline and betaine mitigated the inhibition of growth of BY-2 cells under salt stress and the mitigating effect of proline was more than that of betaine. Salt stress significantly decreased the activities of superoxide dismutase (SOD), catalase and peroxidase in BY-2 cells. Exogenous application of proline or betaine alleviated the reduction in catalase and peroxidase activities but not SOD activity under salt stress. In addition, proline was found to be effective in alleviating the inhibition of salt stress-induced catalase and peroxidase activities in BY-2 cells. Neither proline nor betaine directly scavenged superoxide (O(2)(-)) or hydrogen peroxide (H(2)O(2)). It is concluded that exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine because of its superior ability to increase the activities of antioxidant enzymes. 相似文献
183.
Hoque MA Banu MN Okuma E Amako K Nakamura Y Shimoishi Y Murata Y 《Journal of plant physiology》2007,164(11):1457-1468
Up-regulation of the antioxidant system provides protection against NaCl-induced oxidative damage in plants. Antioxidants and activity of enzymes involved in the ascorbate-glutathione (ASC-GSH) cycle in tobacco Bright Yellow-2 (BY-2) were investigated to assess the antioxidant protection offered by exogenous proline and glycinebetaine (betaine from now on) against salt stress using cells grown in suspension culture. Reduced ascorbate (ASC) was detected in BY-2 cells but dehydroascorbate (DHA) was not. Large quantities of a reduced form of glutathione (GSH) and smaller quantities of an oxidized form of glutathione (GSSG) were detected in BY-2 cells. Salt stress significantly reduced the contents of ASC and GSH as well as activities of ASC-GSH cycle enzymes such as ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR). Exogenous proline or betaine increased the activities of all enzymes except MDHAR involved in NaCl-induced ASC-GSH cycle. Levels of ASC and GSH in BY-2 cells under salt stress were lower in the presence of proline or betaine than in the absence of proline or betaine whereas there was no difference in redox status. Proline proved more effective than betaine in maintaining the activity of enzymes involved in NaCl-induced ASC-GSH cycle. Neither proline nor betaine had any direct protective effect on NaCl-induced enzyme activity involved in the antioxidant system; however, both improved salt tolerance by increasing enzyme activity. The present study, together with our earlier findings [Hoque MA, Okuma E, Banu MNA, Nakamura Y, Shimoishi Y, Murata Y. Exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine by increasing antioxidant enzyme activities. J Plant Physiol 2006;164:553-61.], suggests that proline offered greater protection against salt stress than betaine did because proline was more effective in increasing the activity of enzymes involved in the antioxidant system. 相似文献
184.
Fukaya M Mizuno A Arai H Muto K Uebanso T Matsuo K Yamamoto H Taketani Y Doi T Takeda E 《American journal of physiology. Endocrinology and metabolism》2007,293(2):E515-E522
The hepatoportal region is important for glucose sensing; however, the relationship between the hepatoportal glucose-sensing system and the postprandial rapid phase of the insulin response has been unclear. We examined whether a rapid-phase insulin response to low amounts of intraportal glucose infusion would occur, compared that with the response to intrajugular glucose infusion in conscious rats, and assessed whether this sensing system was associated with autonomic nerve activity. The increases in plasma glucose concentration did not differ between the two infusions at 3 min, but the rapid-phase insulin response was detected only in the intraportal infusion. A sharp and rapid insulin response was observed at 3 min after intraportal infusion of a small amount of glucose but not after intrajugular infusion. Furthermore, this insulin response was also induced by intraportal fructose infusion but not by nonmetabolizable sugars. The rapid-phase insulin response at 3 min during intraportal infusion did not differ between rats that had undergone hepatic vagotomy or chemical sympathectomy with 6-hydroxydopamine compared with control rats, but this response disappeared in rats that had undergone chemical vagotomy with atropine. We conclude that the elevation of glucose concentration in the hepatoportal region induced afferent signals from undetectable sensors and that these signals stimulate pancreas to induce the rapid-phase insulin response via cholinergic nerve action. 相似文献
185.
Shimamoto C Umegaki E Katsu K Kato M Fujiwara S Kubota T Nakahari T 《American journal of physiology. Gastrointestinal and liver physiology》2007,293(4):G824-G837
The effects of intracellular Cl- concentration ([Cl-]i) on acetylcholine (ACh)-stimulated exocytosis were studied in guinea pig antral mucous cells by video microscopy. ACh activated Ca2+-regulated exocytosis (an initial phase followed by a sustained phase). Bumetanide (20 microM) or a Cl- -free (NO3-) solution enhanced it; in contrast, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB, a Cl- channel blocker) decreased it and eliminated the enhancement induced by bumetanide or NO3- solution. ACh and Ca2+ dose-response studies demonstrated that NO3- solution does not shift their dose-response curves, and ATP depletion studies by dinitrophenol or anoxia demonstrated that exposure of NO3- solution prior to ATP depletion induced an enhanced initial phase followed by a sustained phase, whereas exposure of NO3- solution after ATP depletion induced only a sustained phase. Intracellular Ca2+ concentration ([Ca2+]i) measurements showed that bumetanide and NO3- solution enhanced the ACh-stimulated [Ca2+]i increase. Measurements of [Cl-]i revealed that ACh decreases [Cl-]i and that bumetanide and NO3- solution decreased [Cl-]i and enhanced the ACh-evoked [Cl-]i decrease; in contrast, NPPB increased [Cl-]i and inhibited the [Cl-]i decrease induced by ACh, bumetanide, or NO3- solution. These suggest that [Cl-]i modulates [Ca2+]i increase and ATP-dependent priming. In conclusion, a decrease in [Cl-]i accelerates ATP-dependent priming and [Ca2+]i increase, which enhance Ca2+-regulated exocytosis in ACh-stimulated antral mucous cells. 相似文献
186.
Kobayashi M Abiru N Arakawa T Fukushima K Zhou H Kawasaki E Yamasaki H Liu E Miao D Wong FS Eisenbarth GS Eguchi K 《Journal of immunology (Baltimore, Md. : 1950)》2007,179(4):2082-2088
Insulin peptide B:9-23 is a major autoantigen in type 1 diabetes that contains two distinct CD4 epitopes (B:9-16 and B:13-23). One of the two epitopes, B:13-23, overlaps with a CTL epitope (B:15-23). In this study, we report that the elimination of the CTL epitope from the B:9-23 peptide by amino acid substitution (with alanine) at positions B:16 and 19 (A16,19 altered peptide ligand) or truncation of the C-terminal amino acids from the peptide (B:9-21), neither of which stimulated the proliferation of insulin B:15-23 reactive CD8 T cells, provided significant intranasally induced suppression of diabetes when coadministered with a potent mucosal adjuvant cholera toxin (CT). Intranasal treatment with A16,19 resulted in the elimination of spontaneous insulin autoantibodies, significant inhibition of insulitis and remission from hyperglycemia, and prevented the progression to diabetes. Intranasal administration of native B:9-23/CT or B:11-23/CT resulted in a significant enhancement of insulin autoantibody expression and severity of insulitis and failed to prevent diabetes. Our present study indicates that elimination of the CTL epitope from the B:9-23 peptide was critically important for mucosally induced diabetes prevention. The A16,19 altered peptide ligand, but not other native insulin peptides, suppresses insulin autoantibodies associated with protection from and remission of diabetes. 相似文献
187.
Matsuki Y Ohmura-Hoshino M Goto E Aoki M Mito-Yoshida M Uematsu M Hasegawa T Koseki H Ohara O Nakayama M Toyooka K Matsuoka K Hotta H Yamamoto A Ishido S 《The EMBO journal》2007,26(3):846-854
The presence of post-translational regulation of MHC class II (MHC II) under physiological conditions has been demonstrated recently in dendritic cells (DCs) that potently function as antigen-presenting cells (APCs). Here, we report that MARCH-I, an E3 ubiquitin ligase, plays a pivotal role in the post-translational regulation of MHC II in B cells. MARCH-I expression was particularly high in B cells, and the forced expression of MARCH-I induced the ubiquitination of MHC II. In B cells from MARCH-I-deficient mice (MARCH-I KO), the half-life of surface MHC II was prolonged and the ubiquitinated form of MHC II completely disappeared. In addition, MARCH-I-deficient B cells highly expressed exogenous antigen-loaded MHC II on their surface and showed high ability to present exogenous antigens. These results suggest that the function of MHC II in B cells is regulated through ubiquitination by MARCH-I. 相似文献
188.
Identification of a Sterol Δ7 Reductase Gene Involved in Desmosterol Biosynthesis in Mortierella alpina 1S-4 下载免费PDF全文
Molecular cloning of the gene encoding sterol Δ7 reductase from the filamentous fungus Mortierella alpina 1S-4, which accumulates cholesta-5,24-dienol (desmosterol) as the main sterol, revealed that the open reading frame of this gene, designated MoΔ7SR, consists of 1,404 bp and codes for 468 amino acids with a molecular weight of 53,965. The predicted amino acid sequence of MoΔ7SR showed highest homology of 51% with that of sterol Δ7 reductase (EC 1.3.1.21) from Xenopus laevis (African clawed frog). Heterologous expression of the MoΔ7SR gene in yeast Saccharomyces cerevisiae revealed that MoΔ7SR converts ergosta-5,7-dienol to ergosta-5-enol (campesterol) by the activity of Δ7 reductase. In addition, with gene silencing of MoΔ7SR gene by RNA interference, the transformant accumulated cholesta-5,7,24-trienol up to 10% of the total sterols with a decrease in desmosterol. Cholesta-5,7,24-trienol is not detected in the control strain. This indicates that MoΔ7SR is involved in desmosterol biosynthesis in M. alpina 1S-4. This study is the first report on characterization of sterol Δ7 reductase from a microorganism. 相似文献
189.
190.
Akimoto Y Hart GW Wells L Vosseller K Yamamoto K Munetomo E Ohara-Imaizumi M Nishiwaki C Nagamatsu S Hirano H Kawakami H 《Glycobiology》2007,17(2):127-140
Many nuclear and cytoplasmic proteins are O-glycosylated on serine or threonine residues with the monosaccharide beta-N-acetylglucosamine, which is then termed O-linked N-acetylglucosamine (O-GlcNAc). It has been shown that abnormal O-GlcNAc modification (O-GlcNAcylation) of proteins is one of the causes of insulin resistance and diabetic complications. In this study, in order to examine the relationship between O-GlcNAcylation of proteins and glucose-stimulated insulin secretion in noninsulin-dependent type (type 2) diabetes, we investigated the level of O-GlcNAcylation of proteins, especially that of PDX-1, and the expression of O-GlcNAc transferase in Goto-Kakizaki (GK) rats, which are an animal model of type-2 diabetes. By immunoblot and immunohistochemical analyses, the expression of O-GlcNAc transferase protein and O-GlcNAc-modified proteins in whole pancreas and islets of Langerhans of 15-week-old diabetic GK rats and nondiabetic Wistar rats was examined. The expression of O-GlcNAc transferase at the protein level and O-GlcNAc transferase activity were increased significantly in the diabetic pancreas and islets. The diabetic pancreas and islets also showed an increase in total cellular O-GlcNAc-modified proteins. O-GlcNAcylation of PDX-1 was also increased. In the diabetic GK rats, significant increases in the immunoreactivities of both O-GlcNAc and O-GlcNAc transferase were observed. PUGNAc, an inhibitor of O-GlcNAcase, induced an elevation of O-GlcNAc level and a decrease of glucose-stimulated insulin secretion in isolated islets. These results indicate that elevation of the O-GlcNAcylation of proteins leads to deterioration of insulin secretion in the pancreas of diabetic GK rats, further providing evidence for the role of O-GlcNAc in the insulin secretion. 相似文献