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21.
The effect of quercetin on cell cycle progression and growth of human gastric cancer cells 总被引:10,自引:0,他引:10
M Yoshida T Sakai N Hosokawa N Marui K Matsumoto A Fujioka H Nishino A Aoike 《FEBS letters》1990,260(1):10-13
Quercetin, a flavonoid, is found in many plants, including edible fruits and vegetables. We examined the effects on cell growth of human malignant cells derived from the gastrointestinal tract and on cell cycle progression. Quercetin markedly inhibited the growth of human gastric cancer cells and the IC50 value was 32-55 microM. DNA synthesis was suppressed to 14% of the control level by the treatment with 70 microM quercetin for 2 days. Furthermore, quercetin blocked cell progression from the G1 to the S phase. 相似文献
22.
Tetsuya Fukui Akio Yoshimoto Mamoru Matsumoto Shunji Hosokawa Terumi Saito Hiroko Nishikawa Kenkichi Tomita 《Archives of microbiology》1976,110(2-3):149-156
The enzyme activity synthesizing poly--hydroxybutyrate (PHB) was mainly localized in the PHB-containing particulate fraction ofZoogloea ramigera I-16-M, when it grew flocculatedly in a medium supplemented with glucose. On the other hand, the enzyme activity remained in the soluble fraction, when the bacterium grew dispersedly in a glucose-starved medium.The soluble PHB synthase activity became associated with the particulate fraction as PHB synthesis was initiated on the addition of glucose to the dispersed culture. Conversely, the enzyme activity was released from the PHB-containing granules to the soluble fraction when the flocculated culture was kept incubated without supplementing the medium with glucose.PHB synthase was also incorporated into the newly formed PHB fraction when partially purified soluble PHB synthase was incubated withd(-)--hydroxybutyryl CoA in vitro.Although attempts to solubilize the particulate enzyme were unsuccessful, and the soluble enzyme became extremely unstable in advanced stages of purification, both PHB synthases had the same strict substrate specificity ford(-)--hydroxybutyryl CoA, and showed the same pH optimum at 7.0.Non-Standard Abbreviations PHB
poly--hydroxybutyrate 相似文献
23.
24.
Eri Akita Yaxiaer Yalikun Kazunori Okano Yuki Yamasaki Misato Ohtani Yo Tanaka Taku Demura Yoichiroh Hosokawa 《Plant Biotechnology》2020,37(4):417
Atomic force microscopy (AFM) can measure the mechanical properties of plant tissue at the cellular level, but for in situ observations, the sample must be held in place on a rigid support and it is difficult to obtain accurate data for living plants without inhibiting their growth. To investigate the dynamics of root cell stiffness during seedling growth, we circumvented these problems by using an array of glass micropillars as a support to hold an Arabidopsis thaliana root for AFM measurements without inhibiting root growth. The root elongated in the gaps between the pillars and was supported by the pillars. The AFM cantilever could contact the root for repeated measurements over the course of root growth. The elasticity of the root epidermal cells was used as an index of the stiffness. By contrast, we were not able to reliably observe roots on a smooth glass substrate because it was difficult to retain contact between the root and the cantilever without the support of the pillars. Using adhesive to fix the root on the smooth glass plane overcame this issue, but prevented root growth. The glass micropillar support allowed reproducible measurement of the spatial and temporal changes in root cell elasticity, making it possible to perform detailed AFM observations of the dynamics of root cell stiffness. 相似文献
25.
Human carboxylesterase 1 (hCES1) is an enzyme that plays an important role in hydrolysis of pharmaceuticals in the human liver. In this study, elucidation of the chiral recognition ability of hCES1 was attempted using indomethacin esters in which various chiral alcohols were introduced. Indomethacin was condensed with various chiral alcohols to synthesize indomethacin esters. The synthesized esters were hydrolyzed with a human liver microsome (HLM) solution and a human intestine microsome (HIM) solution. High hydrolytic rate and high stereoselectivity were confirmed in the hydrolysis reaction in the HLM solution but not in the HIM solution, and these indomethacin esters were thought to be hydrolyzed by hCES1. Next, these indomethacin esters were hydrolyzed in recombinant hCES1 solution and the hydrolysis rates of the esters were calculated. The stereoselectivity confirmed in HLM solution was also confirmed in the hCES1 solution. In the hydrolysis reaction of esters in which a phenyl group is bonded next to the ester, the Vmax value of the (R) form was 10 times larger than that of the (S) form. 相似文献
26.
Shota Tanaka Mika Hosokawa Takumi Miyamoto Aiko Nakagawa Mika Haruna Kumiko Ueda Seigo Iwakawa Ken-ichi Ogawara 《Biochemistry and Biophysics Reports》2021
microRNAs (miRNAs) contained in small extracellular vesicles (sEVs) are candidates for non-invasive biomarkers. Oxaliplatin (L-OHP) has been approved for advanced colorectal cancer (CRC) chemotherapy. However, the response to L-OHP differs among CRC patients. In addition, CRC cells often acquire the resistance to L-OHP. This study aimed at the prediction of L-OHP sensitivity by measuring extracellular miRNAs levels. Firstly, we compared intracellular miRNAs expressions in L-OHP-sensitive CRC cells (SW620 and HCT116 cells) with those in acquired and intrinsic L-OHP-resistant cells. In microarray and real-time RT-PCR analyses, the intracellular miR-33a-5p, miR-210–3p, and miR-224–5p expressions were lower in acquired and intrinsic L-OHP-resistant CRC cells than sensitive cells. Furthermore, in SW620 cells, L-OHP sensitivity was decreased by miR-33a-5p inhibitor. On the other hand, miR-210–3p or miR-224–5p inhibitor did not affect L-OHP sensitivity in SW620 cells. Secondly, the amount of miR-33a-5p, miR-210–3p, and miR-224–5p in sEVs was compared. The amount of miR-33a-5p and miR-210–3p in sEVs secreted from acquired and intrinsic L-OHP-resistant cells tended to be small. miR-224–5p was not detected in sEVs secreted from three types of CRC cells examined. To the best of our knowledge, this is the first study demonstrating that miR-33a-5p and/or miR-210–3p in sEVs would be candidates for biomarkers of L-OHP sensitivity. In particular, miR-33a-5p is a promising candidate because it would be directly involved in L-OHP sensitivity. 相似文献
27.
Hiroyuki Hosokawa Phat Vinh Dip Maria Merkulova Anastasia Bakulina Zhenjie Zhuang Ashok Khatri Xiaoying Jian Shawn M. Keating Stephanie A. Bueler John L. Rubinstein Paul A. Randazzo Dennis A. Ausiello Gerhard Grüber Vladimir Marshansky 《The Journal of biological chemistry》2013,288(8):5896-5913
Previously, we reported an acidification-dependent interaction of the endosomal vacuolar H+-ATPase (V-ATPase) with cytohesin-2, a GDP/GTP exchange factor (GEF), suggesting that it functions as a pH-sensing receptor. Here, we have studied the molecular mechanism of signaling between the V-ATPase, cytohesin-2, and Arf GTP-binding proteins. We found that part of the N-terminal cytosolic tail of the V-ATPase a2-subunit (a2N), corresponding to its first 17 amino acids (a2N(1–17)), potently modulates the enzymatic GDP/GTP exchange activity of cytohesin-2. Moreover, this peptide strongly inhibits GEF activity via direct interaction with the Sec7 domain of cytohesin-2. The structure of a2N(1–17) and its amino acids Phe5, Met10, and Gln14 involved in interaction with Sec7 domain were determined by NMR spectroscopy analysis. In silico docking experiments revealed that part of the V-ATPase formed by its a2N(1–17) epitope competes with the switch 2 region of Arf1 and Arf6 for binding to the Sec7 domain of cytohesin-2. The amino acid sequence alignment and GEF activity studies also uncovered the conserved character of signaling between all four (a1–a4) a-subunit isoforms of mammalian V-ATPase and cytohesin-2. Moreover, the conserved character of this phenomenon was also confirmed in experiments showing binding of mammalian cytohesin-2 to the intact yeast V-ATPase holo-complex. Thus, here we have uncovered an evolutionarily conserved function of the V-ATPase as a novel cytohesin-signaling receptor. 相似文献
28.
Tatsuji Sakamoto Misako Inui Kana Yasui Sachiko Hosokawa Hideshi Ihara 《Applied microbiology and biotechnology》2013,97(3):1121-1130
We previously isolated two α-l-arabinofuranosidases (ABFs), termed AFQ1 and AFS1, from the culture filtrate of Penicillium chrysogenum 31B. afq1 and afs1 complementary DNAs encoding AFQ1 and AFS1 were isolated by in vitro cloning. The deduced amino acid sequences of AFQ1 and AFS1 are highly similar to those of Penicillium purpurogenum ABF 2 and ABF 1, respectively, which belong to glycoside hydrolase (GH) families 51 and 54, respectively. Pfam analysis revealed an “Alpha-L-AF_C” domain in AFQ1 and “ArabFuran-catal” and “AbfB” domains in AFS1. Semi-quantitative RT-PCR analysis indicated that the afq1 gene was constitutively expressed in P. chrysogenum 31B at a low level, although the expression was slightly induced with arabinose, arabinitol, arabinan, and arabinoxylan. In contrast, expression of the afs1 gene was strongly expressed by the above four carbohydrates and less strongly induced by galactan. Recombinant enzymes (rAFQ1 and rAFS1) expressed in Escherichia coli were active against both p-nitrophenyl α-l-arabinofuranoside and polysaccharides with different specificities. 1H-NMR analysis revealed that rAFS1 degraded arabinofuranosyl side chains that were both singly and doubly linked to the backbones of arabinoxylan and l-arabinan. On the other hand, rAFQ1 preferentially released arabinose linked to C-3 of single-substituted xylose or arabinose residues in the two polysaccharides. 相似文献
29.
Tomoyoshi Hosokawa Kunio Ando Gakuzo Tamura 《Bioscience, biotechnology, and biochemistry》2013,77(11):2865-2869
γ-Aminobutyric acid (GABA), a hypotensive compound, and alanine accumulated in tea leaves under anaerobic conditions. Since the 15N in 15N-glutamic acid was well incorporated in GABA and alanine during anaerobic incubation, glutamic acid seemed to be a source of nitrogen for the increased GABA and alanine. GOT and GPT were the predominant amino acid transaminases in tea leaves. Although glutamate decarboxylase and GPT seemed to be important for GABA and alanine accumulation, the activities of these enzymes did not increase under anaerobic conditions. Glutamate decarboxylase, which formed GABA from glutamate, was purified 52.4-fold. This enzyme, with an optimum pH at 5.8, was activated by pyridoxal phosphate and used only l-glutamic acid as a substrate. 相似文献
30.