Characterizing the role of host blood cells in a beneficial symbiosis

许多动物与细菌结成终生有益的关系。这些共生关系往往是物种特异性的，因此必须有有效的机制来确保建立稳定的伙伴关系。鱿鱼，Euprymna scolopes和生物发光细菌fischeri弧菌之间的共生关系是了解有益细菌对动物定植和发育影响的有用模型。幼乌贼孵化时没有费氏弧菌，必须从含有少量潜在共生菌和许多非共生菌的海水中获取。宿主必须在其一生中维持这些共生体，同时排除其他细菌。最近的研究表明，免疫系统在介导这些相互作用中起着重要作用。宿主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，表明宿主的免疫系统被“教育”到共生细菌的存在。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介导。本项目将探讨宿主血细胞如何介导鱿鱼/弧菌共生的特异性。这些血细胞表达的基因和蛋白质将被表征为对定植和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关联的早期被表征，以了解宿主免疫系统识别和适应（“教育”）共生体的潜在机制。该项目将把研究与教育结合起来，为培养本科生、研究生和博士后（包括来自代表性不足群体的学生）做出贡献。研究结果将通过科学出版物和公共共生网站发布。

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.