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131.
Chizuru Akatsu Duriya Fongmoon Shuji Mizumoto Jean-Claude Jacquinet Prachya Kongtawelert Shuhei Yamada Kazuyuki Sugahara 《Glycoconjugate journal》2010,27(4):387-399
Glycosaminoglycans (GAGs) like chondroitin sulfate (CS) and heparan sulfate (HS) are synthesized on the tetrasaccharide linkage
region, GlcAβ1-3Galβ1-3Galβ1-4Xylβ1-O-Ser, of proteoglycans. The Xyl can be modified by 2-O-phosphate in both CS and HS, whereas the Gal residues can be sulfated at C-4 and/or C-6 in CS but not in HS. To study the
roles of these modifications, monoclonal antibodies were developed against linkage glycopeptides of shark cartilage CS proteoglycans,
and one was characterized in detail. This antibody bound hexa- and pentasaccharide-peptides more strongly than unsaturated
tetrasaccharide-peptides with the unnatural fourth sugar residue (unsaturated hexuronic acid), suggesting the importance of
the fifth and/or fourth saccharide residue GalNAc-5 and/or GlcA-4. Its reactivity was not affected by treatment with chondro-4-sulfatase
or alkaline phosphatase, suggesting that 4-O-sulfate on the Gal residues and 2-O-phosphate on the Xyl residue were not recognized. Treatment with weak alkali to cleave the Xyl-Ser linkage completely abolished
the binding activity, suggesting the importance of the peptide moiety of the hexasaccharide-peptide for the binding. Based
on the amino acid composition and matrix-assisted laser desorption ionization time-of-flight mass spectrometry analyses, it
was revealed that the peptide moiety is composed of four amino acids, Ser, Pro, Gly, and Glu. Furthermore, the antibody stained
wild-type CHO cells significantly, but much weakly mutant cells deficient in xylosyl- or galactosyltransferase-I required
for the biosynthesis of the linkage region. These results suggest that the antibody recognizes the structure GalNAc(±6-O-sulfate)-GlcA-Gal-Gal-Xyl-Ser-(Pro, Gly, Glu). The antibody will be a useful tool for investigating the significance of the
linkage region in the biosynthesis and/or intracellular transport of different GAG chains especially since such tools to study
the linkage region are lacking. 相似文献
132.
Yasuhiro Ohshima Mitsutoshi Tsukimoto Takato Takenouchi Hitoshi Harada Akina Suzuki Mitsuru Sato Hiroshi Kitani Shuji Kojima 《Biochimica et Biophysica Acta (BBA)/General Subjects》2010
Background
Ionizing irradiation causes not only growth arrest and cell death, but also release of growth factors or signal transmitters, which promote cancer malignancy. Extracellular ATP controls cancer growth through activation of purinoceptors. However, there is no report of radiation-induced ATP release from cancer cells. Here, we examined γ-irradiation-induced ATP release and its mechanism in B16 melanoma.Methods
Extracellular ATP was measured by luciferin–luciferase assay. To investigate mechanism of radiation-induced ATP release, we pharmacologically inhibited the ATP release and established stable P2X7 receptor-knockdown B16 melanoma cells using two short hairpin RNAs targeting P2X7 receptor.Results
Cells were exposed to 0.5–8 Gy of γ-rays. Extracellular ATP was increased, peaking at 5 min after 0.5 Gy irradiation. A selective P2X7 receptor channel antagonist, but not anion transporter inhibitors, blocked the release of ATP. Further, radiation-induced ATP release was significantly decreased in P2X7 receptor-knockdown cells. Our results indicate that γ-irradiation evokes ATP release from melanoma cells, and P2X7 receptor channel plays a significant role in mediating the ATP release.General Significance
We suggest that extracellular ATP could be a novel intercellular signaling molecule released from cancer cells when cells are exposed to ionizing radiation. 相似文献133.
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136.
Jürgen Geisler Takashi Suzuki Hildegunn Helle Yasuhiro Miki Shuji Nagasaki Nhat K. Duong Dagfinn Ekse Turid Aas Dean B. Evans Per E. Lønning Hironobu Sasano 《The Journal of steroid biochemistry and molecular biology》2010,118(4-5):237-241
Breast cancer tissue estrogen levels on an average exceed plasma as well as benign breast tissue levels. To evaluate the contribution of intra-tumor aromatization to individual tumor estrogen levels (estradiol, E2; estrone, E1; estrone sulfate, E1S), breast cancer tissue sections obtained during mastectomy in 28 postmenopausal breast cancer patients were stained for aromatase protein expression using the aromatase antibody 677. The findings were correlated to intra-tumor estrogen levels determined with a highly sensitive HPLC-RIA. Staining with 677 alone (irrespective of the hormone receptor status) revealed no difference in tumor E2 levels comparing 677+ versus 677? tumors, although a non-significant trend towards higher tumor E1 and E1S levels was observed in 677+ breast cancers. In contrast, tumor levels of E2 were significantly higher in ER+ tumors compared to ER? tumors (P < 0.001) and to benign breast tissue from the same breast (P < 0.001). Analysing the additional effect of positive staining with the aromatase antibody 677 on tumor estrogen levels in the subgroup of ER+ tumors, revealed significantly higher tumor levels of E2 (mean level of 544.7 versus 197.1 fmol/g tissue) as well as a non-significant trend concerning tumor E1 (mean level of 296.9 versus 102.1 fmol/g tissue). The mean tumor tissue E1S level was observed somewhat lower in ER+677+ (103.5 fmol/g) versus ER+677? tumors (190.1 fmol/g). In the subgroup of ER+PgR+ tumors, tissue levels of E2 were also found to be significantly higher among 677+ compared to 677? tumors: 873.2 fmol/g (95% CI 395.9–1925.6) versus 217.9 fmol/g (95% CI 88.8–534.9) (P = 0.015).In conclusion, our results indicate a moderate effect of aromatase enzyme expression evaluated by IHC using the antibody 677 on intra-tumor estrogen levels among ER+ breast cancers. A substantial interindividual variation in the ratios between the individual estrogen fractions suggests additional effects, like alterations in other enzymes to be involved in the intra-tumor estrogen homeostasis. 相似文献
137.
A new species of the genus Machilus Nees (Lauraceae) from China, M. parapauhoi F. N. Wei, S. C. Tang & W. B. Xu is described and illustrated. The new species is similar to M. pauhoi Kanehira, but differs in its densely appressed pubescent branchlets and petioles, shorter petiole, 0.8–1.2 cm long and an infructescence conspicuously shorter than the leaf. It is also similar to M. kwangtungensis Yang, but differs by its oblique leaves, with falcately curved apex and 14–18 lateral veins on both sides of the midrib. Based on a study of the type and isotype specimens of M. balansae (Airy Shaw) F. N. Wei & S. C. Tang and M. grandifolia S. Lee & F. N. Wei, M. grandifolia is regarded as a new synonym of M. balansae. 相似文献
138.
Takashi Kobayashi Taro Ehara Takanori Mizuoka Shuji Adachi 《Biotechnology letters》2010,32(11):1679-1684
In order to synthesize a sugar ester at high concentration, 1,2-O-isopropylidene-α-d-glucofuranose (IpGlc), which is one of the sugar acetals and is more hydrophobic than unmodified glucose, was esterified
with palmitic acid at 40°C using immobilized lipase from Candida antarctica in some organic solvents or their mixtures. Acetone + t-butyl alcohol (3:1 v/v) improved both the initial reaction rate and yield after 80 h: the product reached its maximum value
(240 mmol/kg solvent; ca. 110 g/kg solvent) when 400 mmol IpGlc/kg solvent and 1,200 mmol palmitic acid/kg solvent were used
in this solvent mixture. 相似文献
139.
Shuji Inoue Miki Inoue Sayoko Fujimura Ryuichi Nishinakamura 《Genesis (New York, N.Y. : 2000)》2010,48(3):207-212
Sall1 is expressed in the metanephric mesenchyme in the developing kidney, and mice deficient in Sall1 show kidney agenesis or dysgenesis. Sall1 is also expressed elsewhere, including in the limb buds, anus, heart, and central nervous system. Dominant‐negative mutations of Sall1 in mice and humans lead to developmental defects in these organs. Here, we generated a mouse line expressing tamoxifen‐inducible Cre recombinase (CreERT2) under the control of the endogenous Sall1 promoter. Upon tamoxifen treatment, these mice showed genomic recombination in the tissues where endogenous Sall1 is expressed. When CreERT2 mice were crossed with the floxed Sall1 allele, tamoxifen administration during gestation led to a significant decrease in Sall1 expression and small kidneys at birth, suggesting that Sall1 functions were disrupted. Furthermore, Sall1 expression in the kidney was significantly reduced by neonatal tamoxifen treatment. The Sall1CreERT2 mouse is a valuable tool for in vivo time‐dependent and region‐specific knockout and overexpression studies. genesis 48:207–212, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
140.
Smitha Surendran Thamarath A. Alia Esha Roy Karthick Babu Sai Sankar Gupta John H. Golbeck Jörg Matysik 《Photosynthesis research》2013,117(1-3):461-469
The solid-state photo-CIDNP (photochemically induced dynamic nuclear polarization) effect is studied in photosynthetic reaction centers of Heliobacillus mobilis at different magnetic fields by 13C MAS (magic-angle spinning) NMR spectroscopy. Two active states of heliobacterial reaction centers are probed: an anaerobic preparation of heliochromatophores (“Braunstoff”, German for “brown substance”) as well as a preparation of cells after exposure to oxygen (“Grünstoff”, “green substance”). Braunstoff shows significant increase of enhanced absorptive (positive) signals toward lower magnetic fields, which is interpreted in terms of an enhanced differential relaxation (DR) mechanism. In Grünstoff, the signals remain emissive (negative) at two fields, confirming that the influence of the DR mechanism is comparably low. 相似文献