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排序方式: 共有1406条查询结果,搜索用时 172 毫秒
161.
Kikuchi Y Uno S Yoshimura Y Otabe K Iida S Oheda M Fukushima N Tsuchiya M 《Biochemical and biophysical research communications》2004,315(4):912-918
We constructed a single-chain antibody fragment (scFv) of murine monoclonal antibody, MABL, which specifically bound to human CD47 (hCD47) and induced apoptosis of the leukemic cells. The scFv of MABL antibody with a 15-residue linker (MABL scFv-15) formed both dimer (Mr 50 kDa) and monomer (Mr 25 kDa). Both MABL scFv-15 dimer and monomer had binding activity for hCD47. MABL scFv-15 dimer strongly induced apoptosis of hCD47-introduced mouse leukemic cells in vitro and exhibited anti-tumor effect in a myeloma transplanted mice model. However, MABL scFv-15 monomer scarcely exhibited these activities. These results strongly demonstrate that the ligation of CD47 antigen by two antigen-binding sites of MABL dimer is needed for inducing apoptosis. The parent MABL antibody caused hemagglutination due to the CD47 expressed on erythrocytes. Interestingly, MABL scFv-15 dimer did not cause hemagglutination. This apoptosis-inducing dimer appears to be a lead candidate for novel leukemic therapy. 相似文献
162.
The procerebrum (PC) of the terrestrial mollusk Limax is a highly developed second-order olfactory center consisting of two electrophysiologically distinct populations of neurons: nonbursting (NB) and bursting (B). NB neurons are by far the more numerous of the two cell types. They receive direct synaptic inputs from afferent fibers from the tentacle ganglion, the primary olfactory center, and also receive periodic inhibitory postsynaptic potentials (IPSPs) from B neurons. Odor-evoked activity in the NB neurons was examined using perforated patch recordings. Stimulation of the superior tentacle with odorants resulted in inhibitory responses in 45% of NB neurons, while 11% of NB neurons showed an excitatory response. The specific response was reproducible in each neuron to the same odorant, suggesting the possibility that activity of NB neurons may encode odor identity. Analysis of the cycle-averaged membrane potential of NB neurons revealed a correlation between the firing rate and the membrane potential at the plateau phase between IPSPs. Also, the firing rate of NB neurons was affected by the frequency of the IPSPs. These results indicate the existence of two distinct mechanisms for the regulation of NB neuron activity. 相似文献
163.
TAGE (toxic AGEs) theory in diabetic complications 总被引:6,自引:0,他引:6
Sato T Iwaki M Shimogaito N Wu X Yamagishi S Takeuchi M 《Current molecular medicine》2006,6(3):351-358
Diabetic complication is a leading cause of acquired blindness, end-stage renal failure, a variety of neuropathies and accelerated atherosclerosis. Chronic hyperglycemia is initially involved in the pathogenesis of diabetic micro- and macro-vascular complications via various metabolic derangements. High glucose increased production of various types of advanced glycation end-products (AGEs). Recently, we found that glyceraldehyde-derived AGEs (AGE-2) play an important role in the pathogenesis of angiopathy in diabetic patients. There is considerable interest in receptor for AGEs (RAGE) found on many cell types, particularly those affected in diabetes. Recent studies suggest that interaction of AGE-2 (predominantly structure of toxic AGEs; TAGE) with RAGE alters intracellular signaling, gene expression, release of pro-inflamatory molecules and production of reactive oxygen species (ROS) that contribute towards the pathology of diabetic complications. We propose three pathways for the in vivo formation of AGE-2 precursor, glyceraldehyde, such as i) glycolytic pathway, ii) polyol pathway, and iii) fructose metabolic pathway. Glyceraldehyde can be transported or can leak passively across the plasma membrane. It can react non-enzymatically with proteins to lead to accelerated formation of TAGE at both intracellularly and extracellularly. In this review, we discuss the molecular mechanisms of diabetic complications, especially focusing on toxic AGEs (TAGE) and their receptor (RAGE) system. 相似文献
164.
Prokaryotes are known to have evolved one or more unique organelles. Although several hypotheses have been proposed concerning the biogenesis of these intracellular components, the majority of these proposals remains unclear. Magnetotactic bacteria synthesize intracellular magnetosomes that are enclosed by lipid bilayer membranes. From the identification and characterization of several surface and transmembrane magnetosome proteins, we have postulated that magnetosomes are derived from the cytoplasmic membrane (CM). To confirm this hypothesis, a comparative proteomic analysis of the magnetosome membrane (MM) and CM of the magnetotactic bacterium, Magnetospirillum magneticum AMB-1, was undertaken. Based on the whole genome sequence of M. magneticum AMB-1, 78 identified MM proteins were also found to be prevalent in the CM, several of which are related to magnetosome biosynthesis, such as Mms13, which is tightly bound on the magnetite surface. Fatty acid analysis was also conducted, and showed a striking similarity between the CM and MM profiles. These results suggest that the MM is derived from the CM. 相似文献
165.
Ryu Osaka Masayoshi Watada Daisuke Kageyama Masashi Nomura 《Symbiosis (Philadelphia, Pa.)》2010,52(1):41-45
A maternally-inherited spiroplasma endosymbiont of Drosophila hydei does not exert apparent phenotypes on both sexes of its host and is prevalent in natural populations of D. hydei. Our previous experiments using a laboratory stock of D. hydei revealed that low temperatures (such as 15°C and 18°C) dramatically lower the vertical transmission rates of this spiroplasma.
Therefore, we hypothesized that, in temperate regions, the infection frequencies may decrease in cool seasons but increase
in the summer season. To clarify the temporal population dynamics of the spiroplasma infection, D. hydei were collected from two Japanese populations in 2006–2008 from May to early August, representing the only period when a number
of D. hydei are collectable in Japan, and examined for spiroplasma infection. Within each year, the frequency of spiroplasma infection
fluctuated considerably in both populations. Consistent with our hypothesis, the infection frequency showed an increasing
trend in both populations in 2007. However, the data in 2006 and 2008 did not show consistent patterns of increase. The population
dynamics of spiroplasma infection may be affected but not critically determined by temperature. Moreover, despite the fluctuation
within each year, the infection frequencies seemed to be stable across the years. The frequencies of spiroplasma infection
in D. hydei populations may be stabilized by multiple factors. One of these factors may involve a context-dependent positive effect of
spiroplasma on the fitness of D. hydei, as was recently observed in laboratory experiments. 相似文献
166.
To investigate the production of useful phenols from plant resources, we examined the metabolism of cinnamic acid derivatives by a wood-rotting fungus, Schizophyllum commune. Four cinnamic acid derivatives (cinnamic, p-coumaric, ferulic, and sinapic acids) were tested as substrates. Two main reactions, reduction and cleavage of the side chain, were observed. Reduction of the side chain was confirmed in cinnamic acid and p-coumaric acid metabolism. The side chain cleavage occurred in p-coumaric acid and ferulic acid metabolism but the initial reactions of these acids differed. Sinapic acid was not metabolized by S. commune. p-Hydroxybenzaldehyde accumulation was observed in the culture to which p-coumaric acid was added. This suggests that S. commune is a useful agent for transforming p-coumaric acid into p-hydroxybenzaldehyde. 相似文献
167.
Yano K Tansengco ML Hio T Higashi K Murooka Y Imaizumi-Anraku H Kawaguchi M Hayashi M 《Molecular plant-microbe interactions : MPMI》2006,19(7):801-810
Legume plants develop specialized root organs, the nodules, through a symbiotic interaction with rhizobia. The developmental process of nodulation is triggered by the bacterial microsymbiont but regulated systemically by the host legume plants. Using ethylmethane sulfonate mutagenesis as a tool to identify plant genes involved in symbiotic nodule development, we have isolated and analyzed five nodulation mutants, Ljsym74-3, Ljsym79-2, Ljsym79-3, Ljsym80, and Ljsym82, from the model legume Lotus japonicus. These mutants are defective in developing functional nodules and exhibit nitrogen starvation symptoms after inoculation with Mesorhizobium loti. Detailed observation revealed that infection thread development was aborted in these mutants and the nodules formed were devoid of infected cells. Mapping and complementation tests showed that Ljsym74-3, and Ljsym79-2 and Ljsym79-3, were allelic with reported mutants of L. japonicus, alb1 and crinkle, respectively. The Ljsym82 mutant is unique among the mutants because the infection thread was aborted early in its development. Ljsym74-3 and Ljsym80 were characterized as mutants with thick infection threads in short root hairs. Map-based cloning and molecular characterization of these genes will help us understand the genetic mechanism of infection thread development in L. japonicus. 相似文献
168.
Song HS Lan Phi NT Park YH Sawamura M 《Bioscience, biotechnology, and biochemistry》2006,70(3):737-739
A comparison of the volatile profiles between Korean and Japanese Shiranui cold-pressed peel oil was performed by GC and GC-MS. Limonene was the most abundant in the Japanese (91.8%) and Korean (86.4%) oil. Alcohols accounted for 1.8% in the Korean oil, and 0.2% in the Japanese oil, in which the respective linalool levels were 1.2% and 0.1%. The level of aldehydes was also higher in the Korean oil (1.6%) than in the Japanese oil (0.7%). 相似文献
169.
Effects of inducible nitric oxide synthase inhibitors on asthma depending on administration schedule
Abe M Hayashi Y Murai A Shibata K Sakata N Igarashi R Katsuragi T Tanaka K 《Free radical biology & medicine》2006,40(6):1083-1095
The effectiveness of two inducible nitric oxide synthase (iNOS) inhibitors on allergic airway inflammation was investigated under different administration schedules. Rats sensitized to ovalbumin (OVA) were exposed to OVA for 3 consecutive days. Both iNOS inhibitors showed markedly different effects between two pretreatment schedules: pretreatment before each of three OVA exposures S1 and before the third exposure alone S2. S1 pretreatment resulted in higher pulmonary resistance than triple OVA alone. This potentiation was associated with increased eosinophil infiltration and malondialdehyde levels in the lungs, which were suppressed by superoxide dismutases (SODs) but not by methylprednisolone. However, the S2 administration of both iNOS inhibitors completely suppressed the airway response. Administration by schedule S1 completely suppressed plasma nitrite and nitrate levels, but that by S2 caused only a slight suppression. The triple OVA exposures resulted in the upregulation of iNOS in alveolar macrophages and arginase activity, Mn- and Cu/Zn-SOD expression, and nitrotyrosine and lipid peroxide deposition in the airway. However, inhibitors administered by schedule S1 suppressed this upregulation, but further potentiated nitrotyrosine, which in turn was inhibited by SOD. Although iNOS inhibitors may be beneficial for asthma, repeated administration may be detrimental because of extensive reduction of NO and downregulation of SOD. 相似文献
170.
Research suggests that abnormal coordination patterns between the thorax and pelvis in the transverse plane observed in patients with Parkinson's disease and the elderly might be due to alteration in axial trunk stiffness. The purpose of this study was to develop a tool to estimate axial trunk stiffness during walking and to investigate its functional role. Fourteen healthy young subjects participated in this study. They were instructed to walk on the treadmill and kinematic data was collected by 3D motion analysis system. Axial trunk stiffness was estimated from the angular displacement between trunk segments and the amount of torque around vertical axis of rotation. The torque due to arm swing cancelled out the torque due to the axial trunk stiffness during walking and the thoracic rotation was of low amplitude independent of changes in walking speeds within the range used in this study (0.85-1.52 m/s). Estimated axial trunk stiffness increased with increasing walking speed. Functionally, the suppression of axial rotation of thorax may have a positive influence on head stability as well as allowing recoil between trunk segments. Furthermore, the increased stiffness at increased walking speed would facilitate the higher frequency rotation of the trunk in the transverse plane required at the higher walking speeds. 相似文献