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51.
Yukiko Yamada Tatsuya Awano Minoru Fujita Keiji Takabe 《Trees - Structure and Function》2011,25(4):607-616
A living wood fiber (LWF) is one that retains the living protoplast. LWFs store numerous starch grains during the dormant
period. In black locust (Robinia pseudoacacia), almost all wood fibers in the outer part of the annual ring are LWFs. In the outermost ring, starch is accumulated during
the summer, retained in winter, and metabolized during spring. We determined the starch content of LWFs, ray parenchyma, and
axial parenchyma using image analysis. More than 70% of the starch grains in the outermost ring were stored in LWFs during
winter. After the breakdown of starch in spring, LWFs resulted in cell death. These results indicate that LWFs in black locust
function as “single-use” large-capacity starch storage. 相似文献
52.
53.
Hideki Shiba Tsuyoshi Fujita Naomi Doi Shigeo Nakamura Keiji Nakanishi Toshinobu Takemoto Takamune Hino Mitsuhide Noshiro Takeshi Kawamoto Hidemi Kurihara Yukio Kato 《Journal of cellular physiology》1998,174(2):194-205
The purpose of this study is to differentiate roles of several growth factors and cytokines in proliferation and differentiation of pulp cells during development and repair. In human pulp cell cultures, laminin and type I collagen levels per cell remained almost constant during the whole culture period (22 days). On the other hand, secreted protein, acidic and rich in cysteine (SPARC/osteonectin) and alkaline phosphatase (ALPase) levels markedly increased after the cultures reached confluence. Laminin and type I collagen, as well as fibronectin, stimulated the spreading of pulp cells within 1 h. Adding transforming growth factor-β (TGF-β) decreased laminin and ALPase levels, whereas it increased SPARC and fibronectin levels 3- to 10-fold. Western and Northern blots showed that TGF-β enhanced SPARC synthesis at the protein and mRNA levels. Basic fibroblast growth factor (bFGF) decreased type I collagen, laminin, SPARC, and ALPase levels without changing the fibronectin level. Platelet-derived growth factor (PDGF) selectively decreased laminin, SPARC, and ALPase levels. Epidermal growth factor (EGF) also decreased SPARC and ALPase levels. Tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) decreased type I collagen and laminin levels, and abolished SPARC and ALPase syntheses. Of these peptides, bFGF and PDGF showed the greatest stimulation of [3H]thymidine incorporation into DNA. TGF-β, EGF, and TNF-α had less effect on DNA synthesis, whereas IL-1β inhibited DNA synthesis. These findings demonstrated that TGF-β, bFGF, EGF, PDGF, TNF-α, and IL-1β have characteristically different patterns of actions on DNA, laminin, type I collagen, fibronectin, ALPase, and SPARC syntheses by pulp cells. J. Cell. Physiol. 174:194–205, 1998. © 1998 Wiley-Liss, Inc. 相似文献
54.
Yoshiteru Sasaki Soichi Sano Masaki Nakahara Shigeo Murata Kohei Kometani Yuichi Aiba Shinji Sakamoto Yoshihiro Watanabe Keiji Tanaka Tomohiro Kurosaki Kazuhiro Iwai 《The EMBO journal》2013,32(18):2463-2476
The linear ubiquitin chain assembly complex (LUBAC) plays a crucial role in activating the canonical NF‐κB pathway, which is important for B‐cell development and function. Here, we describe a mouse model (B‐HOIPΔlinear) in which the linear polyubiquitination activity of LUBAC is specifically ablated in B cells. Canonical NF‐κB and ERK activation, mediated by the tumour necrosis factor (TNF) receptor superfamily receptors CD40 and TACI, was impaired in B cells from B‐HOIPΔlinear mice due to defective activation of the IKK complex; however, B‐cell receptor (BCR)‐mediated activation of the NF‐κB and ERK pathways was unaffected. B‐HOIPΔlinear mice show impaired B1‐cell development and defective antibody responses to thymus‐dependent and thymus‐independent II antigens. Taken together, these data suggest that LUBAC‐mediated linear polyubiquitination is essential for B‐cell development and activation, possibly via canonical NF‐κB and ERK activation induced by the TNF receptor superfamily, but not by the BCR. 相似文献
55.
Takeshi Ohe Aki Suzuki Tetsushi Watanabe Tomohiro Hasei Haruo Nukaya Yukari Totsuka Keiji Wakabayashi 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》2009,678(1):38-42
We recently identified dichlorobiphenyl (DCB) derivatives and 2-phenylbenzotriazole (PBTA) congeners as major mutagenic constituents of the waters of the Waka River and the Yodo River system in Japan, respectively. In this study we examined sister chromatid exchange (SCE) induction by two dichlorobiphenyl derivatives, 3,3′-dichlorobenzidine (DCB, 4,4′-diamino-3,3′-dichlorobiphenyl) and 4,4′-diamino-3,3′-dichloro-5-nitrobiphenyl (5-nitro-DCB); three PBTA congeners, 2-[2-(acetylamino)-4-[bis(2-methoxyethyl)amino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-1), 2-[2-(acetylamino)-4-[N-(2-cyanoethyl)ethylamino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-2), and 2-[2-(acetylamino)amino]-4-[bis(2-hydroxyethyl)amino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-6); and water concentrates from the Waka River in Chinese hamster lung (CHL) cells. Concentration-dependent induction of SCE was found for all DCBs and PBTAs examined in the presence of S9 mix, and statistically significant increases of SCEs were detected at 2 μg per ml of medium or higher concentrations. SCE induction of MeIQx was examined to compare genotoxic activities of these water pollutants. According to the results, a ranking of the SCE-inducing potency of these compounds is the following: 5-nitro-DCB ≈ MeIQx > PBTA6 > PBTA-1 ≈ PBTA-2 > DCB.Water samples collected at a site at the Waka River showed concentration-related increases in SCEs at 6.25–18.75 ml-equivalent of river water per ml of medium with S9 mix. The concentrations of 5-nitro-DCB and DCB in the river water samples were from 2.5 to 19.4 ng/l and from 4100 to 18,900 ng/l, respectively. However, these chemicals showed only small contribution to SCE induction by the Waka River water. 相似文献
56.
Tsusaki K Watanabe H Yamamoto T Nishimoto T Chaen H Fukuda S 《Bioscience, biotechnology, and biochemistry》2012,76(4):721-731
Highly branched α-glucan molecules exhibit low digestibility for α-amylase and glucoamylase, and abundant in α-(1→3)-, α-(1→6)-glucosidic linkages and α-(1→6)-linked branch points where another glucosyl chain is initiated through an α-(1→3)-linkage. From a culture supernatant of Paenibacillus sp. PP710, we purified α-glucosidase (AGL) and α-amylase (AMY), which were involved in the production of highly branched α-glucan from maltodextrin. AGL catalyzed the transglucosylation reaction of a glucosyl residue to a nonreducing-end glucosyl residue by α-1,6-, α-1,4-, and α-1,3-linkages. AMY catalyzed the hydrolysis of the α-1,4-linkage and the intermolecular or intramolecular transfer of maltooligosaccharide like cyclodextrin glucanotransferase (CGTase). It also catalyzed the transfer of an α-1,4-glucosyl chain to a C3- or C4-hydroxyl group in the α-1,4- or α-1,6-linked nonreducing-end residue or the α-1,6-linked residue located in the other chains. Hence AMY was regarded as a novel enzyme. We think that the mechanism of formation of highly branched α-glucan from maltodextrin is as follows: α-1,6- and α-1,3-linked residues are generated by the transglucosylation of AGL at the nonreducing ends of glucosyl chains. Then AMY catalyzes the transfer of α-1,4-chains to C3- or C4-hydroxyl groups in the α-1,4- or α-1,6-linked residues generated by AGL. Thus the concerted reactions of both AGL and AMY are necessary to produce the highly branched α-glucan from maltodextrin. 相似文献
57.
Youichi Kawakita Kazuhiro Miwa Masaki Seto Hiroshi Banno Yoshikazu Ohta Toshiya Tamura Tadashi Yusa Hiroshi Miki Hidenori Kamiguchi Yukihiro Ikeda Toshimasa Tanaka Keiji Kamiyama Tomoyasu Ishikawa 《Bioorganic & medicinal chemistry》2012,20(20):6171-6180
During the course of our studies on a novel HER2/EGFR dual inhibitor (TAK-285), we found an alternative potent pyrrolo[3,2-d]pyrimidine compound (1a). To enhance the pharmacokinetic (PK) profile of this compound, we conducted chemical modifications into its N-5 side chain and conversion of the chemically modified compounds into their salts. Among them, 2cb, the tosylate salt of compound 2c, showed potent HER2/EGFR kinase inhibitory activity (IC50: 11/11 nM) and cellular growth inhibitory activity (BT-474 cell GI50: 56 nM) with a good drug metabolism and PK (DMPK) profile. Furthermore, 2cb exhibited significant in vivo antitumor efficacy in both mouse and rat xenograft models with transplanted 4-1ST gastric cancer cell lines (mouse, T/C = 0%, 2cb po bid at 100 mg/kg; rat, T/C: -1%, 2cb po bid at 25 mg/kg). 相似文献
58.
Keiji Uchiyama Hironori Miyata Masashi Yano Yoshitaka Yamaguchi Morikazu Imamura Naomi Muramatsu Nandita Rani Das Junji Chida Hideyuki Hara Suehiro Sakaguchi 《PloS one》2014,9(10)
Prion infection induces conformational conversion of the normal prion protein PrPC, into the pathogenic isoform PrPSc, in prion diseases. It has been shown that PrP-knockout (Prnp0/0) mice transgenically reconstituted with a mouse-hamster chimeric PrP lacking N-terminal residues 23-88, or Tg(MHM2Δ23-88)/Prnp0/0 mice, neither developed the disease nor accumulated MHM2ScΔ23-88 in their brains after inoculation with RML prions. In contrast, RML-inoculated Tg(MHM2Δ23-88)/Prnp0/+ mice developed the disease with abundant accumulation of MHM2ScΔ23-88 in their brains. These results indicate that MHM2Δ23-88 itself might either lose or greatly reduce the converting capacity to MHM2ScΔ23-88, and that the co-expressing wild-type PrPC can stimulate the conversion of MHM2Δ23-88 to MHM2ScΔ23-88 in trans. In the present study, we confirmed that Tg(MHM2Δ23-88)/Prnp0/0 mice remained resistant to RML prions for up to 730 days after inoculation. However, we found that Tg(MHM2Δ23-88)/Prnp0/0 mice were susceptible to 22L prions, developing the disease with prolonged incubation times and accumulating MHM2ScΔ23-88 in their brains. We also found accelerated conversion of MHM2Δ23-88 into MHM2ScΔ23-88 in the brains of RML- and 22L-inoculated Tg(MHM2Δ23-88)/Prnp0/+ mice. However, wild-type PrPSc accumulated less in the brains of these inoculated Tg(MHM2Δ23-88)/Prnp0/+ mice, compared with RML- and 22L-inoculated Prnp0/+ mice. These results show that MHM2Δ23-88 itself can convert into MHM2ScΔ23-88 without the help of the trans-acting PrPC, and that, irrespective of prion strains inoculated, the co-expressing wild-type PrPC stimulates the conversion of MHM2Δ23-88 into MHM2ScΔ23-88, but to the contrary, the co-expressing MHM2Δ23-88 disturbs the conversion of wild-type PrPC into PrPSc. 相似文献
59.
60.
Takeshita H Kitano M Iwasaki T Kitano S Tsunemi S Sato C Sekiguchi M Azuma N Miyazawa K Hla T Sano H 《Biochemical and biophysical research communications》2012,419(2):154-159
Sphingosine 1-phosphate (S1P)/S1P receptor 1 (S1P1) signaling plays an important role in synovial cell proliferation and inflammatory gene expression by rheumatoid arthritis (RA) synoviocytes. The purpose of this study is to clarify the role of S1P/S1P1 signaling in the expression of receptor activator of NF-κB ligand (RANKL) in RA synoviocytes and CD4(+) T cells. We demonstrated MH7A cells, a human RA synovial cell line, and CD4(+) T cells expressed S1P1 and RANKL. Surprisingly, S1P increased RANKL expression in MH7A cells and CD4(+) T cells in a dose-dependent manner. Moreover, S1P enhanced RANKL expression induced by stimulation with TNF-α in MH7A cells and CD4(+) T cells. These effects of S1P in MH7A cells were inhibited by pretreatment with PTX, a specific Gi/Go inhibitor. These findings suggest that S1P/S1P1 signaling may play an important role in RANKL expression by MH7A cells and CD4(+) T cells. S1P/S1P1 signaling of RA synoviocytes is closely connected with synovial hyperplasia, inflammation, and RANKL-induced osteoclastogenesis in RA. Thus, regulation of S1P/S1P1 signaling may become a novel therapeutic target for RA. 相似文献