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121.
Sako M Inagaki S Esaka Y Deyashiki Y 《Bioorganic & medicinal chemistry letters》2003,13(20):3497-3498
Chemical modification of 2'-deoxyguanosine and DNA by excessive acetaldehyde and crotonaldehyde were significantly accelerated by the presence of histones, which are nuclear proteins very rich in the basic amino acids such as L-arginine and L-lysine, resulting in the smooth and selective formation of the corresponding cyclic 1,N(2)-propanoguanine adducts under physiological conditions. Thus, histones have a very close connection with the genotoxic and carcinogenic effects of these aldehydes. 相似文献
122.
Homing endonucleases (HEs) of the LAGLIDADG family cleave intron/inteinless cognate DNA at, or near, the insertion site (IS) of their own intron/intein. Here, we describe a notable exception to this rule. Two introns, Pog.S1205 (length 32 bp) and Pog.S1213 (664 bp), whose ISs are 8 bp apart, exist within the 16S rRNA gene of the archaeon Pyrobaculum oguniense. Pog.S1213 harbors a nested open reading frame (ORF) encoding a 22 kDa monomeric protein, I-PogI, which contains two LAGLIDADG motifs and has optimal DNA cleavage activity at 90 degrees C. Intriguingly, I-PogI cleaves the Pog.S1205-less substrate DNA in the presence or absence of Pog.S1213. The cleavage site (CS) of I-PogI does not coincide with the IS of Pog.S1213 but with that of Pog.S1205. Thus, I-PogI activity both promotes the homing of its own intron, Pog.S1213, and guarantees co-conversion of the ORF-less intron Pog.S1205. 相似文献
123.
124.
Kimura H Hoshino Y Hara S Nishikawa K Sako M Hirayama M Komada Y Morishima T 《Microbiology and immunology》2002,46(8):579-582
The viral load in peripheral blood from patients with Epstein-Barr virus (EBV)-associated hemophagocytic syndrome was measured by real-time quantitative PCR and compared with that in infectious mononucleosis. Patients with EBV-associated hemophagocytic syndrome generally had larger viral burdens, although it was difficult to differentiate EBV-associated hemophagocytic syndrome from infectious mononucleosis simply by viral load. The difference in viral load seemed to be clearer in peripheral blood mononuclear cells than in plasma. 相似文献
125.
We investigated changes in the circadian rhythm of peak expiratory flow (PEF) in seven persons with nocturnal asthma for a 24h span when (1) they were symptom free and their disease was stable, (2) their asthma deteriorated and nocturnal symptoms were frequent, and (3) they were treated with theophylline chronotherapy. Subjects recorded their PEF every 4h between 07:00 and 23:00 one day each period. Circadian rhythms in PEF were assessed using the group-mean cosinor method. The circadian rhythm in PEF varied according to asthma severity. Significant circadian rhythms in PEF were detected during the period when asthma was stable and when it was unstable and nocturnal symptoms were frequent. When nocturnal symptoms were present, the bathyphase (trough time) of the PEF rhythm narrowed to around 04:00; during this time of unstable asthma, the amplitude of the PEF pattern increased 3.9-fold compared to the symptom-free period. No significant group circadian rhythm was detected during theophylline chronotherapy. Evening theophylline chronotherapy proved to be prophylactic for persons whose symptoms before treatment had occurred between midnight and early morning. Changes in the characteristics of the circadian rhythm of PEF, particularly amplitude and time of bathyphase, proved useful in determining when to institute theophylline chronotherapy to avert nocturnal asthma symptoms. (Chronobiology International, 17(4), 513-519, 2000) 相似文献
126.
Fumiko Nishida Miyuki Nishijima Kenichi Mochida Hiroshi Sano Norimichi Nomura Yoshihiko Sako Tadashi Maruyama 《FEMS microbiology letters》1999,174(2):339-346
Aeropyrum pernix is the first strictly aerobic hyperthermophile known to grow heterotrophically at neutral pH and at temperatures up to 100°C. Using a simple and sensitive frit-fast atom bombardment liquid chromatography/mass spectrometry quinone analysis method, we analyzed the quinones in A. pernix. This organism contained demethylmenaquinone analogs (DMK-6(Hn)) and methionaquinone analogs (MTK-6(Hn)) when it was grown under vigorous shaking in the presence of air. The quinones were partially or fully saturated with six isoprenyl units. Although DMK and MTK are the quinones found in eubacteria, this is the first report to demonstrate the simultaneous occurrence of DMK and MTK in archaea. The effect of Na2S2O3 on the quinone composition was studied at concentrations of 0, 0.1 and 0.5% under aerobic growth conditions with shaking. The total quinone content was highest (83.4 μg g−1 dry cell weight) at 0.1% Na2S2O3. In the absence of Na2S2O3, only DMK-6 analogs were detected. While DMK analogs such as DMK-6(H12), DMK-6(H10) and DMK-6(H8) were the major quinones at 0.1% Na2S2O3, MTK analogs such as MTK-6(H12) and MTK-6(H10) were also detected. When the Na2S2O3 concentration was increased to 0.5%, both DMK-6(H8) and MTK-6(H10) disappeared, while MTK-6(H12) increased to approximately 20% of the total quinone content. When A. pernix was grown under oxygen limitation in a tightly closed bottle without gas phase, MK-6(H10) appeared. 相似文献
127.
The 13,738 bp mitochondrial DNA from the cestode Echinococcus multilocularis has been sequenced. It contains two major noncoding regions and 36 genes (12 for proteins involved in oxidative phosphorylation, two for rRNAs and 22 for tRNAs) but a gene for ATPase subunit 8 is missing. All genes are transcribed in the same direction. Putative secondary structures of tRNAs indicate that most of them are conventional clover leaves but the dihydrouridine arm is unpaired in tRNA(Ser(AGN)), tRNA(Ser(UCN)), tRNA(Arg) and tRNA(Cys). The base composition at the wobble positions of fourfold degenerate codon families is highly biased toward U and against C. 相似文献
128.
Ryota Iino Tatsuya Iida Akihiko Nakamura Ei-ichiro Saita Huijuan You Yasushi Sako 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(2):241-252
Background
Biological molecular machines support various activities and behaviors of cells, such as energy production, signal transduction, growth, differentiation, and migration.Scope of review
We provide an overview of single-molecule imaging methods involving both small and large probes used to monitor the dynamic motions of molecular machines in vitro (purified proteins) and in living cells, and single-molecule manipulation methods used to measure the forces, mechanical properties and responses of biomolecules. We also introduce several examples of single-molecule analysis, focusing primarily on motor proteins and signal transduction systems.Major conclusions
Single-molecule analysis is a powerful approach to unveil the operational mechanisms both of individual molecular machines and of systems consisting of many molecular machines.General significance
Quantitative, high-resolution single-molecule analyses of biomolecular systems at the various hierarchies of life will help to answer our fundamental question: “What is life?” This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato. 相似文献129.
Hiroyuki Sako Kazumasa Fukuda Yoshiro Saikawa Rieko Nakamura Tsunehiro Takahashi Norihito Wada Hirohumi Kawakubo Hiroya Takeuchi Tai Ohmori Yuko Kitagawa 《PloS one》2014,9(9)
Despite the benefits of imatinib for treating gastrointestinal stromal tumors (GIST), the prognosis for high risk GIST and imatinib-resistant (IR) GIST remains poor. The mechanisms of imatinib resistance have not yet been fully clarified. The aim of the study was to establish imatinib-resistant cell lines and investigate nilotinib, a second generation tyrosine kinase inhibitor (TKI), in preclinical models of GIST and imatinib-resistant GIST. For a model of imatinib-resistant GIST, we generated resistant cells from GK1C and GK3C cell lines by exposing them to imatinib for 6 months. The parent cell lines GK1C and GK3C showed imatinib sensitivity with IC50 of 4.59±0.97 µM and 11.15±1.48 µM, respectively. The imatinib-resistant cell lines GK1C-IR and GK3C-IR showed imatinib resistance with IC50 values of 11.74±0.17 µM (P<0.001) and 41.37±1.07 µM (P<0.001), respectively. The phosphorylation status of key cell signaling pathways, receptor tyrosine kinase KIT (CD117), platelet-derived growth factor receptor alpha (PDGFRA) and downstream signaling kinases: serine-threonine kinase Akt (AKT) and extracellular signal-regulated kinase 1/2 (ERK1/2) or the non-receptor tyrosine kinase: proto-oncogene tyrosine-protein kinase Src (SRC), was analyzed in established cell lines and ERK1/2 phosphorylation was found to be increased compared to the parental cells. Nilotinib demonstrated significant antitumor efficacy against GIST xenograft lines and imatinib-resistant GIST cell lines. Thus, nilotinib may have clinical potential for patients with GIST or imatinib-resistant GIST. 相似文献
130.