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61.
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Marine Bacterial Sulfated Fucoglucuronomannan (SFGM) Lyase Digests Brown Algal SFGM into Trisaccharides 总被引:2,自引:0,他引:2
Sakai T Kimura H Kojima K Shimanaka K Ikai K Kato I 《Marine biotechnology (New York, N.Y.)》2003,5(1):70-78
Abstract
Three kinds of trisaccharides were prepared by digesting fucoidan from the brown alga Kjellmaniella crassifolia, with the extracellular enzymes of the marine bacterium Fucobacter marina. Their structures were determined as Δ4,5GlcpUA1-2(L-Fucp(3-O-sulfate)α1-3)D-Manp, Δ4,5GlcpUA1-2(L-Fucp(3-O-sulfate)α1-3)D-Manp(6-O-sulfate), and Δ4,5GlcpUA1-2(L-Fucp(2,4-O-disulfate)α1-3)D-Manp(6-O-sulfate), which indicated the existence of a novel polysaccharide in the fucoidan and a novel glycosidase in the extracellular
enzymes. In order to determine the complete structure of the polysaccharide and the reaction mechanism of the glycosidase,
the fucoidan was partially hydrolyzed to obtain glucuronomannan, which is the putative backbone of the polysaccharide, and
its sugar sequence was determined as (-4-D-GlcpUAβ1-2D-Manpα1-)n, which disclosed that the main structure of the polysaccharide is (-4-D-GlcpUAβ1-2(L-Fucp(3-O-sulfate)α1-3)D-Manpα1-)n. Consequently, the glycosidase was deduced to be an endo-α-D-mannosidase that eliminatively cleaves the α-D-mannosyl linkage between D-Manp and D-GlcpUA residues in the polysaccharide and produces the above trisaccharides. The novel polysaccharide and glycosidase were tentatively
named as sulfated fucoglucuronomannan (SFGM) and SFGM lyase, respectively. 相似文献
64.
Masamichi Takahashi Hitomi Furusawa Pitayakon Limtong Vanlada Sunanthapongsuk Dokrak Marod Samruan Panuthai 《Ecological Research》2007,22(1):160-164
We have examined the surface (0–10 cm) soil characteristics of sites after bamboo (Cephalostachyum pergracile) mass flowering and death (DB sites) in comparison with sites with living bamboo (Bambusa tulda) (LB sites) in a seasonal tropical forest in Thailand. One year after bamboo flowering the DB sites were acidic with lower
concentrations of exchangeable Ca and Mg and soil nitrogen than the LB sites. Therefore, although leaf and root litter of
the dead bamboo was deposited in the DB sites after bamboo flowering, soil nutrient status decreased. 相似文献
65.
Nguyen TM Nakamura H Wakabayashi A Kanagawa T Koyama S Tsutsui T Hamasaki T Kimura T 《Laboratory animals》2012,46(3):225-230
Ultrasonographic assessment of fetal growth to estimate fetal weight has been widely used in clinical obstetrics but not in laboratory mice. Even though it is important to assess fetal growth abnormalities for gene-targeting studies using mice, there have been no reports of accurately estimated fetal weight using fetal biometric parameters in mice. The aim of this study was to establish an accurate mouse formula using fetal biometric parameters under ultrasound imaging. Using a high-frequency ultrasound system with a 40 MHz transducer, we measured 293 fetuses of biparietal diameter and mean abdominal diameter from day 12.5 postcoitus (p.c.) until day 18.5 p.c every day. Thirteen algorithms for humans based on head and/or abdominal measurements were assessed. We established an accurate formula based on measurement of the abdomen in Jcl:ICR mice to investigate gestational complications, such as intrauterine growth restriction. 相似文献
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Aya Obana-Koshino Hitomi Ono Jiro Miura Manabu Sakai Hitoshi Uchida Wataru Nakamura Kanji Nohara Yusuke Maruyama Atsuhiko Hattori Takayoshi Sakai 《PloS one》2015,10(4)
Many organs, including salivary glands, lung, and kidney, are formed by epithelial branching during embryonic development. Branching morphogenesis occurs via either local outgrowths or the formation of clefts that subdivide epithelia into buds. This process is promoted by various factors, but the mechanism of branching morphogenesis is not fully understood. Here we have defined melatonin as a potential negative regulator or “brake” of branching morphogenesis, shown that the levels of it and its receptors decline when branching morphogenesis begins, and identified the process that it regulates. Melatonin has various physiological functions, including circadian rhythm regulation, free-radical scavenging, and gonadal development. Furthermore, melatonin is present in saliva and may have an important physiological role in the oral cavity. In this study, we found that the melatonin receptor is highly expressed on the acinar epithelium of the embryonic submandibular gland. We also found that exogenous melatonin reduces salivary gland size and inhibits branching morphogenesis. We suggest that this inhibition does not depend on changes in either proliferation or apoptosis, but rather relates to changes in epithelial cell adhesion and morphology. In summary, we have demonstrated a novel function of melatonin in organ formation during embryonic development. 相似文献
69.
Akihiro Saito Mizuho Shimizu Hitomi Nakamura Shoko Maeno Riko Katase Eitaro Miwa Kyoko Higuchi Kintake Sonoike 《FEBS letters》2014
HvLhcb1 a major light-harvesting chlorophyll a/b-binding protein in barley, is a critical player in sustainable growth under Fe deficiency. Here, we demonstrate that Fe deficiency induces phosphorylation of HvLhcb1 proteins leading to their migration from grana stacks to stroma thylakoid membranes. HvLhcb1 remained phosphorylated even in the dark and apparently independently of state transition, which represents a mechanism for short-term acclimation. Our data suggest that the constitutive phosphorylation-triggered translocation of HvLhcb1 under Fe deficiency contributes to optimization of the excitation balance between photosystem II and photosystem I, the latter of which is a main target of Fe deficiency. 相似文献
70.
Shoji Tane Aiko Ikenishi Hitomi Okayama Noriko Iwamoto Keiichi I. Nakayama Takashi Takeuchi 《Biochemical and biophysical research communications》2014
Mammalian cardiomyocytes actively proliferate during embryonic stages, following which cardiomyocytes exit their cell cycle after birth. The irreversible cell cycle exit inhibits cardiac regeneration by the proliferation of pre-existing cardiomyocytes. Exactly how the cell cycle exit occurs remains largely unknown. Previously, we showed that cyclin E- and cyclin A-CDK activities are inhibited before the CDKs levels decrease in postnatal stages. This result suggests that factors such as CDK inhibitors (CKIs) inhibit CDK activities, and contribute to the cell cycle exit. In the present study, we focused on a Cip/Kip family, which can inhibit cyclin E- and cyclin A-CDK activities. Expression of p21Cip1 and p27Kip1 but not p57Kip2 showed a peak around postnatal day 5, when cyclin E- and cyclin A-CDK activities start to decrease. p21Cip1 and p27Kip1 bound to cyclin E, cyclin A and CDK2 at postnatal stages. Cell cycle distribution patterns of postnatal cardiomyocytes in p21Cip1 and p27Kip1 knockout mice showed failure in the cell cycle exit at G1-phase, and endoreplication. These results indicate that p21Cip1 and p27Kip play important roles in the cell cycle exit of postnatal cardiomyocytes. 相似文献