Molecular and behavioral studies on signal transducing mechanisms of photomovement responses in microorganisms

微生物光运动反应信号转导机制的分子和行为研究

• 批准号: 08836003
• 负责人: TAKAHASHI Tetsuo
• 金额: $ 1.34万
• 依托单位: Japan Advanced Institute of Science and Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08836003/
• 关键词: phototexis; photophobic response; Euqlena; Chlamydomonas; archaeal rhodopsin; phoborhodopsin; PYP; retinal binding site; Halobacterium; Natronebacterium pharaonis; Ectothiorhodospira halophila; Chlamydomonas reinhardtii; Euglena; phototaxis /

During the period, the following new results were established as to various blue/blue-green photoreceptor-containing photomovement systems of microorganisms.(1)The regulation system of the step-down and the step-up photophobic responses in the flagellate alga Euglena was for the first time revealed to be controlled by exogenous ammonium ion. Ammonium ion specifically increases the fraction of the step-down photophobically cells, whereas L-methionine-DL-sulfoximine, an inhibitor of ammonium assimilation, specifically increases the fraction of step-up photophobically responding cells in a cell suspension. This allowed us to measure independently the true action spectra for both step-up and step-down responses. The results suggested that the two responses are mediated by flavin-containing photoreceptors, having slightly different spectroscopic characters.(2)Despite the reported fact that the receptors for photomovement responses of unicellular green alga Chlamydomonas has little homology … More to archaebacterial rhodopsins, our analog-reconstitution study has revealed a highly similar stereochemical architecture along the retinal binding site between the chlamydomons photoreceptor and halobacterial phoborhodopsin. Though this may suggest a possibility for unidentified photomovement receptor in Chlamydomonas having high homology to phoborhodopsin, we tentatively ascribed the result to a possible convergence in the evolution of blue-green sensitive photoreceptors, This is in accord with several lines of evidence that a wide variety of photoreceptor species mediates photomovement responses of various microorganisms to blue/blue-green light.(3)PYP is one of the unique photoreceptors in eubacteria. We measured step-up photophobic response of Ectothiorhodospira halophila, containing PYP, and found that the action spectrum coincided with the absorption spectrum of PYP.(4)A putative transducer-like protein mediating photophobic response of Ectothiorhodospira halophila has been cloned.(5)A new member of phoborhodopsin was cloned from a halobacterial species from Australian salt lake.(6)Phoborhodopsin from Natronobacteriurm pharaonis has been expressed in E.coil, and the recombinant protein is satisfactory purified by histidine tagging. Less

在此期间，关于微生物的各种含蓝色/蓝绿色光感受器的光运动系统，建立了以下新结果。（1）首次揭示了鞭毛虫眼虫的降压和升压反应的调控系统是由外源铵离子控制的。铵离子特异性地增加步降型嗜热细胞的分数，而L-甲硫氨酸-DL-亚砜亚胺，一种铵同化的抑制剂，特异性地增加细胞悬浮液中步升型嗜热响应细胞的分数。这使我们能够独立地测量升压和降压响应的真实作用光谱。结果表明，这两种反应是由含黄素的光感受器介导的，具有略有不同的光谱特征。（2）尽管报道单细胞绿色衣原体的光运动反应受体几乎没有同源性， ...更多信息 对于古细菌视紫红质，我们的类似物重建研究揭示了沿着衣原体感光体和嗜盐细菌视紫红质之间的视网膜结合位点的高度相似的立体化学结构沿着。虽然这可能表明在衣原体中存在与phoborhodopsin具有高度同源性的未鉴定的光运动受体的可能性，但我们初步将结果归因于蓝绿敏感光感受器进化中的可能趋同。这与多种多样的光感受器物种介导各种微生物对蓝/蓝绿光的光运动响应的几条证据雅阁。（3）PYP是真细菌特有的光感受器之一。本文测定了含PYP的嗜盐外硫红旋藻的升压憎水反应，发现其作用光谱与PYP的吸收光谱相吻合。(4)A介导嗜盐外硫红螺旋菌避光反应的推定转导子样蛋白已被克隆。(5)A从澳大利亚盐湖的一种嗜盐菌中克隆到一个新成员。（6）在大肠杆菌中成功表达了嗜盐菌Phoborhodopsin，并通过组氨酸标签法获得了纯化的蛋白。少

项目成果

Horiguchi, T., Kawai, H., Kubota, M., Takahashi, T., and Watanabe, M.: "Phototactic responses of four marine dinoflagellates with different types of eyespot and chloroplast." Phycological Research. 47 (in the press). (1999)

Horiguchi, T.、Kawai, H.、Kubota, M.、Takahashi, T. 和 Watanabe, M.：“具有不同类型眼斑和叶绿体的四种海洋甲藻的趋光反应。”

Horiguchi,T.,Takahashi,T.et al.: "Phototactic responses of four marine dinoflagellates with different types of eyespot and chloroplast." Phycological Research. 47(in the press).

Horiguchi,T.,Takahashi,T.et al.：“具有不同类型眼斑和叶绿体的四种海洋甲藻的趋光反应。”

Matsunaga,S.,Takahashi,T.et al.: "Control by ammonium ion of the change from step-up to step-down photophobically responding cells in the flagellate alga Euglena gracilis." Plant Cell Physiol.40. 213-221 (1999)

Matsunaga,S.,Takahashi,T.等人：“通过铵离子控制鞭毛藻Euglena gracilis中从升压到降压的避光响应细胞的变化。”

Matsunaga, S., Hori, T., Takahashi, T., Kubota, M., Watanabe, M., Okamoto, K., Masuda, K., and Sugai, M.: "Discovery of signaling effect of UV-B/C light in the extended UV-A/blue-type action spectra for step-down and step-up photophobic responses in the u

Matsunaga, S.、Hori, T.、Takahashi, T.、Kubota, M.、Watanabe, M.、Okamoto, K.、Masuda, K. 和 Sugai, M.：“UV-B 信号效应的发现

Matsunaga,S.: "Discovery of signaling effect of UV B/C light in the extended blue/UV-A-type action spectra for step-down and step-up photophobic responses in the unicellular flgellate alga Euglena gracilis" protoplasma. 201. 45-42 (1998)

Matsunaga,S.：“在扩展的蓝色/UV-A 型作用光谱中发现 UV B/C 光对单细胞鞭毛藻 Euglena gracilis 原生质中递减和递增避光响应的信号效应”。