Morphological, Physiological and Genetic Analysis in Citrus Chimera

Masayuki Izumi,Yoshi Ohashi,Saori Tsunashima,Jinmei Zhou,Shan Wu,Yutaka Hirata 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Chemical Synthesis of Intentionally Misfolded Homogeneous Glycoprotein: A Unique Approach for the Study of Glycoprotein Quality Control

Masayuki Izumi,Yutaka Makimura,Simone Dedola,Akira Seko,Akiko Kanamori,Masafumi Sakono,Yukishige Ito,Yasuhiro Kajihara 한국당과학회 2012 한국당과학회 학술대회 Vol.2012 No.1

Biosynthesis of glycoproteins in the endoplasmic reticulum employs a quality control (QC) system, which discriminates and excludes misfolded malfunctional glycoproteins from correctly folded one. In the QC system, UDP-glucose:glycoprotein glucosyltransferase (UGGT) recognizes misfolded glycoprotein bearing high-mannose type N-glycan and glucosylate it so that the misfolded proteins can interact with molecular chaperones calnexin/calreticulin to attain correctly folded structure. As chemical tools to study glycoprotein quality control system at molecular level, we systematically synthesized misfolded homogeneous glycoproteins bearing high-mannose type oligosaccharide. Interleukin 8 (IL-8) is a nonglycosylated protein consisted of 72 amino acid residues and two disulfide bonds between Cys7–Cys34 and Cys9–Cys50. As a model, we incorporated high-mannose type (Man9GlcNAc2) oligosaccharide at the Asn36. The full-length glycosylpolypeptide chain was successfully synthesized by native chemical ligation between N-terminal 33-amino acid peptide-thioester and C-terminal 39-amino acid glycopeptide, which was prepared with Fmoc-Asn derivative having high-mannose oligosaccharide on the side chain.Extensive folding experiments of chemically synthesized homogeneous IL-8 glycopeptide yielded correctly folded glycoprotein with native disulfide bond patterns as well as misfolded glycoproteins with non-native disulfide bond patterns and a disulfide bond-linked misfolded homodimer. Other misfolded glycoprotein models with one and no disulfide bond and glycopeptides consisted of C-terminal 39-amino acid residues were also prepared. Transfer of glucose residue to these homogeneous glycoprotein analogues by UGGT was analyzed by using LC-MS. This assay proved that the critical endoplasmic reticulum folding sensor enzyme, UGGT recognizes misfolded glycosyl-IL-8s with different preferences. The most favored substrate was a homodimer which exhibits molten globule-like hydrophobic nature, and the least favored substrate was a correctly folded glycosyl-IL-8. Glycoproteins and glycopeptides having non-native disulfide bonds were also favored substrates.

Synthetic Study of Carbohydrate Binding Domain of Siglec7

Akihisa Otsuki,Ryo Okamoto,Masayuki Izumi,Yasuhiro Kajihara 한국당과학회 2012 한국당과학회 학술대회 Vol.2012 No.1

Sialic acid-binding immunoglobulin-like lectin (Siglec) 7 is one of the sialic acid binding protein that plays an important role in immune system. Siglec 7 is expressed on natural killer cells and displays a unique ligand binding properties comparing to the other members of the Siglec family, specifically binds to  2,8-disialyl residues. The precise structural analysis of Siglec 7 has been already performed, and amino acid residues involved in the ligand binding are reported. In such context, we set out the first total chemical synthesis of Siglec 7 carbohydrate binding domain (CBD) which consists of 127 amino acid residues. Since chemical synthesis can easily introduce unnatural amino acids, we envisioned that we could produce an artificial sialic acid binding lectin based on this chemical synthetic strategy. The synthesis of Siglec 7 CBD was carried out by convergent total chemical synthesis. The whole polypeptide was assembled from 5 peptide segments (Figure), which were synthesized by conventional solid phase peptide synthesis. We applied native chemical ligation (NCL) for the coupling of these segments sequentially from C-terminus, combined with alkylation with haloacetoamide or desulfuration reaction. These reactions can provide pseudo-Gln residue or Ala residue from Cys residues at the ligation sites. Based on these strategies we have successfully obtained the full-length polypeptide of Siglec 7 CBD and currently are investigating the in vitro folding step.

Chemical Approach for the Synthesis of Homogeneous Large Glycoproteins

Shohei Imada,Ryo Okamoto,Masayuki Izumi,Yasuhiro Kajihara 한국당과학회 2012 한국당과학회 학술대회 Vol.2012 No.1

Glycoprotiens are responsible in many biological events. However oligosaccharides covalently attached to these proteins always exhibit heterogeneity. This has been a hindrance to investigate what oligosaccharide structure is essential for the individual biological event. Therefore we have examined the chemical synthesis of several glycoproteins such as cytokines consist of 70 to 166 amino acid residues. [1-3] However, glycoproteins used in the cell-cell communication or immune response exhibit larger molecular weight comparing with those of cytokines we have synthesized. Unfortunately, the synthesis of such large and homogeneous glycoproteins is still far from our current achievements, because we have not established an efficient method for the synthesis of large glycoproteins yet. Native chemical ligation[4] is a powerful method to couple two polypeptide chains through a native amide bond. This ligation takes place between peptide-C-terminal thioester and cysteine at the N-terminal of another peptide. Using this ligation between glycopeptide-thioester synthesized by chemical method and long peptide prepared from E. coli expression, we have examined the synthesis of large glycoprotein. In this presentation, we would discuss the first synthesis of large and homogeneous glycosylpolypeptide chain (25 kDa) consists of over 200 amino acid residues.

Clinical Utility of Mac-2 Binding Protein Glycosylation Isomer in Chronic Liver Diseases

Tamaki Nobuharu,Kurosaki Masayuki,Loomba Rohit,Izumi Namiki 대한진단검사의학회 2021 Annals of Laboratory Medicine Vol.41 No.1

An accurate evaluation of liver fibrosis is clinically important in chronic liver diseases. Mac-2 binding protein glycosylation isomer (M2BPGi) is a novel serum marker for liver fibrosis. In this review, we discuss the role of M2BPGi in diagnosing liver fibrosis in chronic hepatitis B and C, chronic hepatitis C after sustained virologic response (SVR), and nonalcoholic fatty liver disease (NAFLD). M2BPGi predicts not only liver fibrosis but also the hepatocellular carcinoma (HCC) development and prognosis in patients with chronic hepatitis B and C, chronic hepatitis C after SVR, NAFLD, and other chronic liver diseases. M2BPGi can also be used to evaluate liver function and prognosis in patients with cirrhosis. M2BPGi levels vary depending on the etiology and the presence or absence of treatment. Therefore, the threshold of M2BPGi for diagnosing liver fibrosis and predicting HCC development has to be adjusted according to the background and treatment status.

Deposition of Aerosols on Leaves in a Cool-temperate Larch Forest in Northern Hokkaido, Japan

Fukazawa Tatsuya,Murao Naoto,Sato Hisashi,Takahashi Masahiro,Akiyama Masayuki,Yamaguchi Takashi,Noguchi Izumi,Takahashi Hiroyuki,Kozuka Chikara,Sakai Rei,Takagi Kentaro,Fujinuma Yasumi,Saigusa Nobuko 한국대기환경학회 2012 Asian Journal of Atmospheric Environment (AJAE) Vol.6 No.4

Aerosol concentrations at the CC-Lag site in the Teshio Experimental Forest increased from winter to spring and sometimes showed extremely high values associated with Kosa and/or forest-fire events. The range and mean of the mass concentrations of aerosol chemical species were as follows: total particulate mass, 1.2-29, 5.0; elemental carbon, 0.061-2.2, 0.43; organic carbon, 0.059-3.5, 0.79; and sulfate,0.12-6.2, 1.8 μg/m3. The total masses of the deposited particles on hybrid larch and on bamboo leaves were approximately 35 and 30 μg/cm2, respectively. The amounts of soil particles on the leaves were 6 μg/cm2 for the upper part of hybrid larch, 2μg/cm2 for the lower part of hybrid larch, and 1 μg/cm2 for Sasa bamboo leaves. The amounts of deposited black carbon were 2.3 μg/cm2 for the upper part of hybrid larch, 0.6 μg/cm2 for the lower part of hybrid larch, and 0.2 μg/cm2 for Sasa bamboo leaves. Half of the total deposited particular mass was attached on the hybrid larch; however, most of the total deposited mass was adhered on the Sasa bamboo leaves. Regardless of the species, there tend to be more deposited particles on the leaves in the upper part than in the lower part, with only a few meters height difference. Comparing the composition of the deposited particles to that of the atmospheric aerosols without any size cut, the fractions of water-soluble material sulfate and sea salt in the deposited aerosols were about one tenth and one hundredth lower than that in the aerosols, respectively. On the basis of the measured concentration and the deposited amount on leaves, the deposition velocity of black carbon was estimated to be approximately 0.5 cm/s. Aerosol concentrations at the CC-Lag site in the Teshio Experimental Forest increased from winter to spring and sometimes showed extremely high values associated with Kosa and/or forest-fire events. The range and mean of the mass concentrations of aerosol chemical species were as follows: total particulate mass, 1.2-29, 5.0; elemental carbon, 0.061-2.2, 0.43; organic carbon, 0.059-3.5, 0.79; and sulfate,0.12-6.2, 1.8 μg/m3. The total masses of the deposited particles on hybrid larch and on bamboo leaves were approximately 35 and 30 μg/cm2, respectively. The amounts of soil particles on the leaves were 6 μg/cm2 for the upper part of hybrid larch, 2μg/cm2 for the lower part of hybrid larch, and 1 μg/cm2 for Sasa bamboo leaves. The amounts of deposited black carbon were 2.3 μg/cm2 for the upper part of hybrid larch, 0.6 μg/cm2 for the lower part of hybrid larch, and 0.2 μg/cm2 for Sasa bamboo leaves. Half of the total deposited particular mass was attached on the hybrid larch; however, most of the total deposited mass was adhered on the Sasa bamboo leaves. Regardless of the species, there tend to be more deposited particles on the leaves in the upper part than in the lower part, with only a few meters height difference. Comparing the composition of the deposited particles to that of the atmospheric aerosols without any size cut, the fractions of water-soluble material sulfate and sea salt in the deposited aerosols were about one tenth and one hundredth lower than that in the aerosols, respectively. On the basis of the measured concentration and the deposited amount on leaves, the deposition velocity of black carbon was estimated to be approximately 0.5 cm/s.

Deposition of Aerosols on Leaves in a Cool-temperate Larch Forest in Northern Hokkaido, Japan

Tatsuya, Fukazawa,Naoto, Murao,Hisashi, Sato,Masahiro, Takahashi,Masayuki, Akiyama,Takashi, Yamaguchi,Izumi, Noguchi,Hiroyuki, Takahashi,Chikara, Kozuka,Rei, Sakai,Kentaro, Takagi,Yasumi, Fujinuma,Nob Korean Society for Atmospheric Environment 2012 Asian Journal of Atmospheric Environment (AJAE) Vol.6 No.4

Aerosol concentrations at the CC-Lag site in the Teshio Experimental Forest increased from winter to spring and sometimes showed extremely high values associated with Kosa and/or forest-fire events. The range and mean of the mass concentrations of aerosol chemical species were as follows: total particulate mass, 1.2-29, 5.0; elemental carbon, 0.061-2.2, 0.43; organic carbon, 0.059-3.5, 0.79; and sulfate, 0.12-6.2, 1.8 ${\mu}g/m^3$. The total masses of the deposited particles on hybrid larch and on bamboo leaves were approximately 35 and 30 ${\mu}g/cm^2$, respectively. The amounts of soil particles on the leaves were 6 ${\mu}g/cm^2$ for the upper part of hybrid larch, 2 ${\mu}g/cm^2$ for the lower part of hybrid larch, and 1 ${\mu}g/cm^2$ for Sasa bamboo leaves. The amounts of deposited black carbon were 2.3 ${\mu}g/cm^2$ for the upper part of hybrid larch, 0.6 ${\mu}g/cm^2$ for the lower part of hybrid larch, and 0.2 ${\mu}g/cm^2$ for Sasa bamboo leaves. Half of the total deposited particular mass was attached on the hybrid larch; however, most of the total deposited mass was adhered on the Sasa bamboo leaves. Regardless of the species, there tend to be more deposited particles on the leaves in the upper part than in the lower part, with only a few meters height difference. Comparing the composition of the deposited particles to that of the atmospheric aerosols without any size cut, the fractions of water-soluble material sulfate and sea salt in the deposited aerosols were about one tenth and one hundredth lower than that in the aerosols, respectively. On the basis of the measured concentration and the deposited amount on leaves, the deposition velocity of black carbon was estimated to be approximately 0.5 cm/s.