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排序方式: 共有696条查询结果,搜索用时 140 毫秒
1.
Circularity of the Bacillus subtilis chromosome and further studies on its bidirectional replication 总被引:10,自引:0,他引:10
R G Wake 《Journal of molecular biology》1973,77(4):569-575
Replicating, circular chromosomes of Bacillus subtilis have been displayed by autoradiography of samples obtained from thymine-requiring spores germinating in the presence of [3H]thymine and proceeding into the second round of replication. The observed chromosomes have the expected Cairns-type configuration, and the measured length of a completed (non-replicating) chromosome is 900 to 1100 μm.The extent to which bidirectional replication can proceed following initiation of a round has been investigated further. Thymine-requiring spores germinating in the presence of [3H]thymidine were diluted into higher specific activity medium during the first round of replication and autoradiographs prepared from samples obtained shortly afterwards. From the pattern of labelling within individual loops that become visible, it is clear that replication can proceed in a bidirectional manner up to a stage that would account for replication of at least 50% of the whole chromosome. And, until this stage, the replication rates in both directions are approximately equal. 相似文献
2.
Hidenori Suzuki Naomasa Yamamoto Kenjiro Tanoue Hiroh Yamazaki 《The Histochemical journal》1987,19(3):125-136
Summary Using a monoclonal antibody (TM60) against glycoprotein (GP) Ib, we determined immunocytochemically how GPIb is distributed on the platelet surface. When glutaraldehyde-fixed platelets were incubated with TM60, a uniform distribution of ferritin particles which represent the localization of GPIb was observed on the surface membrane of platelets. The particles were distributed at intervals of about 100 nm. The number of ferritin particles on the surface of one side were 2070–4150 (2940 ± 790; mean ±s.d.,n = 10) under the scanning electron microscope. The distribution of ferritin particles was somewhat disarranged on the surface of unfixed platelets incubated with TM60 compared to that in the fixed platelets. Cluster-like structures of ferritin particles were observed in several places. When platelets were activated with ristocetin or thrombin, the distribution of ferritin particles was disturbed and cluster formation was observed in several places on the surface. These findings suggest that GPIb is uniformly distributed on the surface of platelets in the resting state, and that cluster formation occurs during activation of platelets. 相似文献
3.
4.
Masahiro Murakami Ichiro Iuchi Kenjiro Yamagami 《Development, growth & differentiation》1990,32(6):619-627
Changes in yolk phosphoproteins of Oryzias latipes embryos during early development were examined by electrophoresis. Four phosphoproteins were identified in the yolk of blastulae by polyacrylamide gel electrophoresis. Two of them were high molecular weight phosphoproteins containing 0.7% (w/w) phosphorus and with similar amino acid compositions to that of vitellogenin. The other two were low molecular weight phosphoproteins, characterized by high contents of phosphorus [12.2% (w/w)] and serine (44.8 mole%) and low contents of aromatic amino acid residues. From these characteristics, together with their behaviors on DEAE-cellulose chromatography and electrophoresis and low stainability with dyes, the latter two were concluded to be phosvitins. These phosvitins were isolated and partially characterized.
The yolk phosphoproteins, especially the phosvitins, were degraded, their amounts in embryos decreased throughout early development. Studies on the mechanism of endogenous phosphoprotein degradation strongly suggested the participation of some protease(s) that was precipitated on centrifugation of the egg homogenate at 14,000 × g for 10 min. 相似文献
The yolk phosphoproteins, especially the phosvitins, were degraded, their amounts in embryos decreased throughout early development. Studies on the mechanism of endogenous phosphoprotein degradation strongly suggested the participation of some protease(s) that was precipitated on centrifugation of the egg homogenate at 14,000 × g for 10 min. 相似文献
5.
Genyan Liu Huaguang Li Jiaying Shi Wenjie Wang Kenjiro Furuta Di Liu Chunqing Zhao Fumiyo Ozoe Xiulian Ju Yoshihisa Ozoe 《Bioorganic & medicinal chemistry》2019,27(2):416-424
Competitive antagonists (CAs) of ionotropic GABA receptors (GABARs) reportedly exhibit insecticidal activity and have potential for development as novel insecticides for overcoming emerging resistance to traditional GABAR-targeting insecticides. Our previous studies demonstrated that 4,5-disubstituted 3-isoxazolols or 3-isothiazolols are an important class of insect GABAR CAs. In the present study, we synthesized a series of 4-aryl-5-carbamoyl-3-isoxazolols and examined their antagonism of insect GABARs expressed in Xenopus oocytes. Several of these 3-isoxazolols exhibited potent antagonistic activities against housefly and common cutworm GABARs, with IC50 values in the low-micromolar range in both receptors. 4-(3-Amino-4-methylphenyl)-5-carbamoyl-3-isoxazolol (3u) displayed the highest antagonism, with IC50 values of 2.0 and 0.9?μM in housefly and common cutworm GABARs, respectively. Most of the synthesized 3-isoxazolols showed moderate larvicidal activities against common cutworms, with more than 50% mortality at 100?μg/g. These results indicate that 4-monocyclic aryl-5-carbamoyl-3-isoxazolol is a promising scaffold for insect GABAR CA discovery and provide important information for the design and development of GABAR-targeting insecticides with a novel mode of action. 相似文献
6.
Michael L. Yuan Marvalee H. Wake Ian J. Wang 《Evolution; international journal of organic evolution》2019,73(2):231-244
The performance of an organism in its environment frequently depends more on its composite phenotype than on individual phenotypic traits. Thus, understanding environmental adaptation requires investigating patterns of covariation across functionally related traits. The replicated adaptive radiations of Greater Antillean Anolis lizards are characterized by ecological and morphological convergence, thus, providing an opportunity to examine the role of multiple phenotypes in microhabitat adaptation. Here, we examine integrated claw and toepad morphological evolution in relation to habitat partitioning across the adaptive radiations of Greater Antillean anoles. Based on analysis of 428 specimens from 57 species, we found that different aspects of claw morphology were associated with different perch dimensions, with claw height positively associated with perch diameter and claw curvature positively associated with perch height. Patterns of integration also varied across claw and toepad traits, likely driven by correlative selection for performance on smoother and rougher substrates. Finally, rates of evolution differed between claw and toepad traits, with claw length evolving faster than all other traits despite having no predicted functional importance. Our results highlight the multivariate nature of phenotypic adaptation and suggest that phenotypic integration across Greater Antillean anoles is driven by fine‐scale correlative selection based on structural habitat specialization. 相似文献
7.
Aki Isobe Kenjiro Sawada Yasuto Kinose Chifumi Ohyagi-Hara Erika Nakatsuka Hiroshi Makino Tomonori Ogura Tomoko Mizuno Noriko Suzuki Eiichi Morii Koji Nakamura Ikuko Sawada Aska Toda Kae Hashimoto Seiji Mabuchi Tsuyoshi Ohta Ken-ichirou Morishige Hirohisa Kurachi Tadashi Kimura 《PloS one》2015,10(2)
Ovarian cancer remains the most lethal gynecologic cancer and new targeted molecular therapies against this miserable disease continue to be challenging. In this study, we analyzed the expressional patterns of Interleukin-6 (IL-6) and its receptor (IL-6R) expression in ovarian cancer tissues, evaluated the impact of these expressions on clinical outcomes of patients, and found that a high-level of IL-6R expression but not IL-6 expression in cancer cells is an independent prognostic factor. In in vitro analyses using ovarian cell lines, while six (RMUG-S, RMG-1, OVISE, A2780, SKOV3ip1 and OVCAR-3) of seven overexpressed IL-6R compared with a primary normal ovarian surface epithelium, only two (RMG-1, OVISE) of seven cell lines overexpressed IL-6, suggesting that IL-6/IL-6R signaling exerts in a paracrine manner in certain types of ovarian cancer cells. Ovarian cancer ascites were collected from patients, and we found that primary CD11b+CD14+ cells, which were predominantly M2-polarized macrophages, are the major source of IL-6 production in an ovarian cancer microenvironment. When CD11b+CD14+ cells were co-cultured with cancer cells, both the invasion and the proliferation of cancer cells were robustly promoted and these promotions were almost completely inhibited by pretreatment with anti-IL-6R antibody (tocilizumab). The data presented herein suggest a rationale for anti-IL-6/IL-6R therapy to suppress the peritoneal spread of ovarian cancer, and represent evidence of the therapeutic potential of anti-IL-6R therapy for ovarian cancer treatment. 相似文献
8.
Moeko Noguchi-Shinohara Kenjiro Ono Tsuyoshi Hamaguchi Kazuo Iwasa Toshitada Nagai Shoko Kobayashi Hiroyuki Nakamura Masahito Yamada 《PloS one》2015,10(5)
The aim of this study was to evaluate the safety, tolerability and pharmacokinetics of single dose of Melissa officinalis extract which contained rosmarinic acid, including food-effects in healthy individuals. A total of eleven healthy individuals were randomly assigned to treatment arms in the two studies [Study 1 (fasted state) and Study 2 (fed state)]. Rosmarinic acid in serum was measured by a coulometric detection method using High-Performance Liquid Chromatography electrochemical detector. The serum concentration of total rosmarinic acid peaked at 1 hour after administration of Melissa officinalis extract containing 500mg rosmarinic acid in fasted state, with a maximum serum concentration 162.20 nmol/ L. The area under the curve for intact rosmarinic acid was calculated from the serum concentration-time profile to be 832.13 nmol • hour/ L. Food intake increases area under the curve and delayed time at which the maximum serum concentration. Rosmarinic acid supplementation did not affect liver, kidney, or blood cell function parameters. No adverse event was reported by any of the participants due to the study treatment. Single dose of Melissa officinalis extract containing 500 mg rosmarinic acid appears to be safe and tolerable in healthy individuals. Food intake increased the exposure of rosmarinic acid and delayed absorption of rosmarinic acid in healthy individuals.
Trial Registration
Trial Registration: UMIN-CTR UMIN000004997 相似文献9.
Osteological variation is recorded among and within four of the most distinctive species of the Mexican salamander genus Chiropterotriton. Analysis of the data is consistent with the monophyletic status of the genus and documents previously unrecorded intraspecific and interspecific variation. Most of the recorded variation involves qualitative and quantitative proportional differences, but four fixed differences constitute autapomorphic states that affirm and diagnose some species (C. dimidiatus, C. magnipes). Osteological variation in 15 characters is analyzed with respect to predictions generated from four hypotheses: 1) phylogeny, 2) adaptation to specific habitats (the four species include cave-dwelling, terrestrial, and arboreal forms), 3) size-free shape, and 4) size. High levels of intraspecific variation suggest that the characters studied are not subject to rigid functional constraints in salamanders, regardless of size. The pattern predicted by the hypothesis based on size differences seen among these four Chiropterotriton species matches most closely the observed pattern of relative skull robustness. Since size change and heterochrony are often associated in plethodontid evolution, it is likely that changes in developmental timing play a role in the morphological transitions among these morphologically diverse taxa. Webbed feet, miniaturization, body shape, and an unusual tarsal arrangement are morphologies exhibited in species of Chiropterotrition that are shown to be homoplastic with other clades of tropical plethodontids. Although extensive homoplasy in salamanders might be seen as a roadblock to unraveling phylogenetic hypotheses, the homologous developmental systems that appear to underlie such homoplasy may reveal common and consistent evolutionary processes at work. 相似文献
10.
Naoki Kubo Hidehiro Toh Kenjiro Shirane Takayuki Shirakawa Hisato Kobayashi Tetsuya Sato Hidetoshi Sone Yasuyuki Sato Shin-ichi Tomizawa Yoshinori Tsurusaki Hiroki Shibata Hirotomo Saitsu Yutaka Suzuki Naomichi Matsumoto Mikita Suyama Tomohiro Kono Kazuyuki Ohbo Hiroyuki Sasaki 《BMC genomics》2015,16(1)