Characterizing the role of host blood cells in a beneficial symbiosis

许多动物与细菌建立了终生有益的联系。这些共生往往是物种特有的，因此有效的机制必须确保建立稳定的伙伴关系。对于理解有益细菌对动物定植和发育的影响，鱿鱼、真乌贼头节和生物发光细菌费氏弧菌之间的共生是一个有用的模型。幼鱿鱼孵化时没有费氏弧菌，必须从含有少量潜在共生体和许多非共生菌的海水中获得它们。宿主必须在其一生中保持这些共生体，同时排除其他细菌。最近的研究表明，免疫系统在调节这些相互作用中发挥着重要作用。宿主血细胞(血细胞)对共生细菌和非共生细菌有不同的反应；定植改变了这些细胞识别共生细菌的能力，这表明宿主的免疫系统对共生菌的存在变得“受过教育”。由于无脊椎动物缺乏适应性免疫(产生导致免疫记忆的抗体的能力)，这种特异性必须通过宿主的先天免疫系统来调节。这个项目将探索宿主血细胞如何在鱿鱼/弧菌共生中介导特异性。这些血细胞表达的基因和蛋白质将被表征为对定植以及共生和非共生细菌的反应。血细胞对费氏弧菌和环境细菌的反应将在联合的早期阶段进行表征，以了解宿主免疫系统识别并适应(“教育”)共生体的潜在机制。该项目将把研究与教育结合起来，帮助培训本科生、研究生和博士后，包括来自代表性不足群体的学生。结果将通过科学出版物和公共共生网站传播。

Many animals enter into life-long beneficial associations with bacteria. These symbioses are often species-specific, so that effective mechanisms must ensure the establishment of stable partnerships. The symbiosis between the squid, Euprymna scolopes, and the bioluminescent bacterium Vibrio fischeri is a useful model for understanding the influence of beneficial bacteria on animal colonization and development. Juvenile squid hatch without V. fischeri and must obtain them from seawater that contains few potential symbionts and many non-symbiotic bacteria. The host must maintain these symbionts throughout its life while excluding other bacteria. Recent studies suggest that the immune system plays a significant role in mediating these interactions. Host blood cells (hemocytes) have different responses to symbiotic and non-symbiotic bacteria; colonization alters the ability of these cells to recognize symbiotic bacteria, suggesting that the immune system of the host becomes "educated" to the presence of the symbionts. Because invertebrates lack adaptive immunity (the ability to produce antibodies that lead to immunological memory), this specificity must be mediated through the host's innate immune system. This project will explore how host hemocytes mediate specificity in the squid/vibrio symbiosis. The genes and proteins expressed by these hemocytes will be characterized in response to colonization and to symbiotic and non-symbiotic bacteria. Hemocyte responses to V. fischeri and environmental bacteria will be characterized during the early onset of the association to understand the potential mechanisms by which the host's immune system recognizes and becomes adapted ("educated") to the symbiont. This project will integrate research with education by contributing to the training of undergraduate, graduate and post-doctoral students including those from underrepresented groups. Results will be disseminated through scientific publications as well as a public symbiosis website.