Excitation signal processing times in Halobacterium halobium phototaxis.
Excitation signal processing times in Halobacterium halobium phototaxis.
复制标题
嗜盐杆菌趋光性中的激发信号处理时间。
DOI：
10.1016/s0006-3495(86)83530-5
复制
发表时间：
1986
影响因子：
3.4
通讯作者：
Spudich,JL
中科院分区：
文献类型：
--
作者：
Sundberg,SA;Alam,M;Spudich,JL
嗜盐菌的趋光性反应进行了监测与计算机化的细胞跟踪系统耦合到一个电子快门控制光刺激的传递。方向和线速度的变化率的自动分析提供了67毫秒分辨率的游泳逆转检测，允许测量引诱剂和驱避剂刺激的反应的不同阶段。刺激后，有一个潜伏期，其中的人口逆转频率不变，其次是兴奋阶段，逆转频率增加，和一个较慢的适应阶段，逆转频率返回到其刺激前的值。引诱剂受体慢循环或感觉视紫红质（SR）（λ max，587 nm）的照明的逐步减少被细胞解释为不利的刺激，并在0.70 +/- 0.14 s的最小潜伏期后，诱导游泳逆转，峰值反应发生在刺激开始后1.34 +/- 0.07 s。两个不同的驱避反应，在近紫外线/蓝光观察。一个是对400 nm光的逆转响应，这取决于橙红色背景照明，如预期的光中间体排斥形式的SR（λ max，373 nm）。该反应的最小潜伏期与SR引诱剂系统的最小潜伏期大致相同。第二种是对波长（450 nm）比已知SR驱避剂形式吸收的波长更长的光的最小潜伏期（0.40 +/-0.07 s）更短的逆转反应。这一结果证实了最近发现的一个额外的排斥性光系统在此光谱范围内。此外，较长波长的排斥反应是独立的橙红色的背景照明，表明光感受器介导的这种反应是不是SR的光中间体。
Phototaxis responses of Halobacterium halobium were monitored with a computerized cell-tracking system coupled to an electronic shutter controlling delivery of photostimuli. Automated analysis of rates of change in direction and linear speeds provided detection of swimming reversals with 67 ms resolution, permitting measurement of distinct phases of the responses to attractant and repellent stimuli. After stimulation, there was a latency period in which the population reversal frequency was unchanged, followed by an excitation phase in which reversal frequency increased, and a slower adaptation phase in which reversal frequency returned to its prestimulus value. A step-decrease in illumination of the attractant receptor slow-cycling or sensory rhodopsin (SR) (lambda max, 587 nm) was interpreted by the cells as an unfavorable stimulus and, after a minimum latency of 0.70 +/- 0.14 s, induced swimming reversals with the peak response occurring 1.34 +/- 0.07 s after onset of the stimulus. Two distinct repellent responses in the near UV/blue were observed. One was a reversal response to 400 nm light, which was dependent on orange-red background illumination as expected for the photointermediate repellent form of SR (lambda max, 373 nm). The minimum latency of this response was approximately the same as that of the SR attractant system. The second was a reversal response with shorter minimum latency (0.40 +/- 0.07 s) to light of longer wavelength (450 nm) than absorbed by the known SR repellent form. This result confirms recent findings of an additional repellent photosystem in this spectral range. Further, the longer wavelength repellent response is independent of orange-red background illumination, indicating that the photoreceptor mediating this response is not a photointermediate of SR.