An Immunological Method for the Study of Predation on MarineMicrozooplankton

悬浮食性桡足类利用微生物作为猎物目前被认为是海洋浮游营养动力学的重要组成部分。然而，这种联系的实验证据是间接的，因为软体猎物，如纤毛虫原生动物，不会在桡足动物的内脏或粪便颗粒中留下视觉上可识别的遗骸。欧曼博士将使用免疫学方法来识别桡足类动物肠道内容物中的浮游动物残骸。这项工作需要几个步骤，包括；1)对非毛虫原生动物产生抗血清；2)消除不期望的交叉反应；3)测定灵敏度和特异度；4)测定细菌在肠道的停留时间；5)摄入速率的标定；近岸桡足类纤毛虫抗原的初步调查。免疫检测采用点印迹法（ELISPOT；酶联免疫斑点法）。有机物质由植物合成并通过放牧过程重新分配的食物网的概念在陆地和水生环境中都是相似的。然而，海洋食物网的本质是独特的，因为这种营养活动大多发生在微生物之间。通常很难确定由这些小颗粒组成的食物网的结构，更不用说量化某些生物被其他生物捕食的程度了。欧曼博士将运用分子生物学发展的技术来解决浮游生物生态学中一个更有问题的捕食者-猎物关系——没有硬体的海洋原生动物和海洋浮游动物之间的关系。目前关于浮游食物网中这一潜在重要环节的信息很少，而这种新方法可能为分析这些软体原生动物对大型生物的重要性提供一种定量技术。

The utilization of microbial organisms as prey by suspension feeding copepods currently is thought to be a significant part of marine planktonic trophodynamics. However, experimental evidence for this link is indirect because soft bodied prey such as ciliate protozoa do not leave visually identifiable remains in copepod guts or in fecal pellets. Dr. Ohman will use immunological methods for identifying microzooplankton remains in copepod gut contents. The work entails several steps, including; 1) the production of antisera to nonloricate ciliate protozoa; 2) elimination of undesired cross reactions; 3) determination of assay sensitivity and specificity; 4) determination of gut residence time of anitgens; 5) calibration of ingestion rates; 6) preliminary investigation of nearshore copepods for ciliate antigens. Immunoassays will be done by a dot blot assay (ELISPOT; enzyme-linked immunospot). The concept of a food web by which organic material is synthesized by plants and redistributed by grazing processes is similar in both terrestrial and aquatic environments. However, the nature of the marine food web is distinct in that much of this trophic activity takes place among microorganisms. It is often difficult to identify the structure of the food web composed by these small particles, much less to quantify the extent to which certain organisms are preyed upon by others. Dr. Ohman will apply techniques developed in molecular biology to address one of the more problematic predator-prey relationships in plankton ecology - that of marine protozoans without hard parts and marine zooplankton. There is presently little information on this potentially important link in the planktonic food web, and this novel approach may provide a quantitative technique to analyze the importance of these soft bodied protozoa to larger maine organisms.