BEHAVIOR OF BACTERIA--BIOCHEMISTRY AND GENETICS

能动的细菌会被某些化学物质吸引，而被另一些化学物质排斥， 这个过程被称为趋化性。 这些化学物质被大约20种 不同的化学感受器 它们将信息发送给四个 不同的甲基接受趋化蛋白，MCP's。 在已知的过程中 作为激发，MCP告诉鞭毛是否旋转 对于引诱剂是逆时针方向，对于驱避剂是顺时针方向。 然后 关闭激发（即使引诱剂或驱避剂仍然可以 通过一个被称为适应的过程：这包括一个变化 在MCP甲基化水平上。 激发机制至少涉及磷酸化。 工作 该实验室和许多其他实验室旨在进一步揭示这一机制。 本研究计划的目的是找出细菌 可以改变它们的趋化行为。 另一种说法是， 问：细菌能“学习”吗？ 三种类型的学习-已知发生在 动物-将被研究：习惯化，致敏和条件反射 学习 如果细菌能做到其中任何一点， 都失败了 然后通过使用这些突变体， “学习”过程将被阐明。 在第一个探索阶段， 用于测量趋化性的方法是毛细管测定法、swarm 平板、计算机化测定和栓系细胞的使用。 这里发现的机制将有望与 了解高等生物的神经生物学、行为和学习， 包括人类。此外，神经系统疾病可能是 这类研究的帮助。

Motile bacteria are attracted by certain chemical and repelled by others, a process known as chemotaxis. The chemicals are sensed by some twenty different chemoreceptors. These send their information to one of four different Methyl-accepting Chemotaxis Proteins, MCP's. In a process known as excitation, the MCP tells the flagella whether to rotate counterclockwise, for attractants, or clockwise, for repellents. Then excitation is shut off (even though the attractant or repellent may still be present) by a process known as adaptation: This consists of a change in the level of methylation of MCP. The mechanism of excitation involves at least phosphorylation. Work in this and many other laboratories aim to uncover this mechanism further. The objective of the present research proposal is to find out how bacteria can modify their chemotactic behavior. Another way of stating that is to say: Can bacteria "learn"? Three kinds of learning - known to occur in animals - will be studied: habituation, sensitization, and conditioned learning. If bacteria can do any of these, then mutants will be isolated that fail. Then by use of these mutants the biochemistry of these "learning" processes will be elucidated. In the first, exploratory phase, the methods used for measuring chemotaxis are the capillary assay, swarm plates, a computerized assay, and use of tethered cells. The mechanisms discovered here will hopefully have relevance to understanding neurobiology, behavior, and learning in higher organisms, including man. Further, diseases of the nervous system can probably be helped by research of this sort.