Species Interactions in Microbial Mat Communities: VerticalMigration and Tactic Responses

滑行细菌和游动细菌(光营养和化学营养类型)的光感觉和化学感觉运动反应被认为是原始的神经感觉类似物，被认为是增强生物在自然界中生存潜力的适应。在这项提案中，微生物的垂直迁移模式将在各种微生物垫群落中进行研究，这些微生物群落代表着优化昼夜微环境的非常有利的策略。目标将是：量化温泉和其他垫子中运动的每日时间表；通过实验确定生物体对其做出反应的物理和化学线索；以及在迁徙模式或微环境改变时评估存活率或相对生长。在24小时内发生的垂直向上/向下迁移发生在短距离(几毫米)上，这代表了光强、氧气紧张、硫化物浓度和其他化学因素的急剧梯度。这一结果将把战术行为放在以前生态学研究中未确定的自然栖息地的背景下，并将为理解微生物定向运动进化中涉及的“选择性力量”提供数据。

Photosensory and chemosensory motility responses in both gliding and swimming bacteria (phototrophic and chemotrophic types) are regarded as primitive "neurosensory" analogs and are presumed to be adaptations that enhance the survival potential of the organism in nature. In this proposal, diel vertical migration patterns of microorganisms will be examined in a variety of microbial mat communities representing highly advantageous strategies that optimize both the day and night microenvironments. The objective will be to: quantify the diel schedule of movements in hot spring and other mats; to experimentally determine the physical and chemical cues to which organisms respond; and to assess survival rate or comparative growth when migration patterns or microenvironments are altered. The vertical up/down migrations over a 24 hr period occur over short distances (a few mm) that represent sharp gradients in light intensity, oxygen tension, sulfide concentration, and other chemical factors. The results will place tactic behavior in the context of the natural habitat, previously undetermined in ecological studies and will provide data for understanding the "selective forces" involved in the evolution of oriented motility in microorganisms.