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121.
Androgen-dependent neurodegeneration by polyglutamine-expanded human androgen receptor in Drosophila
Takeyama K Ito S Yamamoto A Tanimoto H Furutani T Kanuka H Miura M Tabata T Kato S 《Neuron》2002,35(5):855-864
Spinal and bulbar muscular atrophy (SBMA) is an X-linked, adult-onset, neurodegenerative disorder affecting only males and is caused by expanded polyglutamine (polyQ) stretches in the N-terminal A/B domain of human androgen receptor (hAR). Although no overt phenotype was detected in adult fly eye photoreceptor neurons expressing mutant hAR (polyQ 52), ingestion of androgen or its known antagonists caused marked neurodegeneration with nuclear localization and structural alteration of the hAR mutant. Ligand-independent toxicity was detected with a truncated polyQ-expanded A/B domain alone, which was attenuated with cytosolic trapping by coexpression of the unliganded hAR E/F ligand binding domain. Thus, our findings suggest that the full binding of androgen to the polyQ-expanded hAR mutants leads to structural alteration with nuclear translocation that eventually results in the onset of SBMA in male patients. 相似文献
122.
Assessment of Poliovirus Eradication in Japan: Genomic Analysis of Polioviruses Isolated from River Water and Sewage in Toyama Prefecture 总被引:2,自引:1,他引:1
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Kumiko Matsuura Mitsuhiro Ishikura Hiromu Yoshida Takashi Nakayama Sumiyo Hasegawa Shuji Ando Hitoshi Horie Tatsuo Miyamura Takashi Kitamura 《Applied microbiology》2000,66(11):5087-5091
Seventy-eight poliovirus strains isolated from river water and sewage in Toyama Prefecture, Japan, during 1993 to 1995 were characterized by the PCR-restriction fragment length polymorphism (RFLP) method and by partially sequencing the VP3 and VP1 regions of the viral genome. Of these isolates, 36 were identified as Sabin vaccine strains, and 42 were identified as vaccine variant strains that had less than 1.4% nucleotide divergence from the Sabin strains, including 7 isolates with patterns different from those of Sabin strains as determined by PCR-RFLP analysis. These findings suggest that wild-type poliovirus was not circulating in Toyama Prefecture. 相似文献
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Channelrhodopsin-1 and 2 (ChR1 and ChR2) form cation channels that are gated by light through an unknown mechanism. We tested the DC-gate hypothesis that C167 and D195 are involved in the stabilization of the cation-permeable state of ChRWR/C1C2 which consists of TM1-5 of ChR1 and TM6-7 of ChR2 and ChRFR which consists of TM1-2 of ChR1 and TM3-7 of ChR2. The cation permeable state of each ChRWR and ChRFR was markedly prolonged in the order of several tens of seconds when either C167 or D195 position was mutated to alanine (A). Therefore, the DC-gate function was conserved among these chimeric ChRs. We next investigated the kinetic properties of the ON/OFF response of these bi-stable ChR mutants as they are important in designing the photostimulation protocols for the optogenetic manipulation of neuronal activities. The turning-on rate constant of each photocurrent followed a linear relationship to 0–0.12 mWmm−2 of blue LED light or to 0–0.33 mWmm−2 of cyan LED light. Each photocurrent of bi-stable ChR was shut off to the non-conducting state by yellow or orange LED light in a manner dependent on the irradiance. As the magnitude of the photocurrent was mostly determined by the turning-on rate constant and the irradiation time, the minimal irradiance that effectively evoked an action potential (threshold irradiance) was decreased with time only if the neuron, which expresses bi-stable ChRs, has a certain large membrane time constant (eg. τm > 20 ms). On the other hand, in another group of neurons, the threshold irradiance was not dependent on the irradiation time. Based on these quantitative data, we would propose that these bi-stable ChRs would be most suitable for enhancing the intrinsic activity of excitatory pyramidal neurons at a minimal magnitude of irradiance. 相似文献
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Yusuke Yamagishi Joto Yoshimoto Hiromu Uchiyama Eri Nabeshima Satoshi Nakaba Ugai Watanabe Ryo Funada 《Planta》2013,237(4):1179-1185
The formation of tracheary elements was induced in calli derived from petioles of hybrid poplar (Populus sieboldii × P. grandidentata) after 10 days of culture on medium that lacked auxin but contained 1 μM brassinolide. Some differentiated cells formed broad regions of cell walls and bordered pits, which are typical features of tracheary elements of secondary xylem. Other differentiated cells resembled tracheary elements of primary xylem, with spiral or reticulate thickening of cell walls. The tracheary elements that developed in calli were formed within cell clusters. This induction system provides a new model for studies of the mechanism of differentiation of secondary xylem cells in vitro. 相似文献
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Ryo Egawa Shoko Hososhima Xubin Hou Hidetaka Katow Toru Ishizuka Harukazu Nakamura Hiromu Yawo 《PloS one》2013,8(3)
The calyx-type synapse of chick ciliary ganglion (CG) has been intensively studied for decades as a model system for the synaptic development, morphology and physiology. Despite recent advances in optogenetics probing and/or manipulation of the elementary steps of the transmitter release such as membrane depolarization and Ca2+ elevation, the current gene-manipulating methods are not suitable for targeting specifically the calyx-type presynaptic terminals. Here, we evaluated a method for manipulating the molecular and functional organization of the presynaptic terminals of this model synapse. We transfected progenitors of the Edinger-Westphal (EW) nucleus neurons with an EGFP expression vector by in ovo electroporation at embryonic day 2 (E2) and examined the CG at E8–14. We found that dozens of the calyx-type presynaptic terminals and axons were selectively labeled with EGFP fluorescence. When a Brainbow construct containing the membrane-tethered fluorescent proteins m-CFP, m-YFP and m-RFP, was introduced together with a Cre expression construct, the color coding of each presynaptic axon facilitated discrimination among inter-tangled projections, particularly during the developmental re-organization period of synaptic connections. With the simultaneous expression of one of the chimeric variants of channelrhodopsins, channelrhodopsin-fast receiver (ChRFR), and R-GECO1, a red-shifted fluorescent Ca2+-sensor, the Ca2+ elevation was optically measured under direct photostimulation of the presynaptic terminal. Although this optically evoked Ca2+ elevation was mostly dependent on the action potential, a significant component remained even in the absence of extracellular Ca2+. It is suggested that the photo-activation of ChRFR facilitated the release of Ca2+ from intracellular Ca2+ stores directly or indirectly. The above system, by facilitating the molecular study of the calyx-type presynaptic terminal, would provide an experimental platform for unveiling the molecular mechanisms underlying the morphology, physiology and development of synapses. 相似文献
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Kazuaki Kitano Kazuhiko Kintaka Shigeru Suzuki Kazuyoshi Katamoto Kiyoshi Nara Yoshio Nakao 《Bioscience, biotechnology, and biochemistry》2013,77(9):1761-1762
The absolute configuration of a phytoalexin “Safynol” (3E, 11E)-3, 11-tridecadiene-5, 7, 9-triyne-l, 2-diol (I), separated from Phytophthora drechsleri-infected safflower (Carthamus tinctorius L.) was confirmed. (R) and (S)-safynol were synthesized from 2, 3-O-isopropyli- dene-(S)- and (R)-glyceraldehyde respectively, and the (R) configuration was assigned to the natural product. The inhibitory effects of (R)- and (S)-safynol on mycelial growth of five fungi were almost the same and their ED50 values ranged from 6 to 70 ppm. 相似文献
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