Mechanisms and Kinetic Characterization of Bacteriolysis in Deposit Feeders

P.I. Plante, Craig J. 提案编号：9504505 项目摘要 细菌在沉积系统中发挥着双重作用：作为有机碎屑的矿化剂以及作为原生动物和无脊椎动物的食物。 细菌的生物量、产量和群落组成决定了这些作用的特征。 该研究的主要目的是评估沉积物饲养者摄入对沉积细菌群落定性和定量方面的重要性。 选择进行深入研究的主要动物是以沉积物为食的多毛类动物，Arencola marina。 其他多毛类动物（Amphitrite johnstoni 和 Clymenella torquata）、半索动物类（Stereobalanus canadensis 和 Saccoglossus kowlevskyi）、无足海参（Caudina areata）和双壳类软体动物（Macoma balthica）也将被研究以进行种间比较。 将确定以消化表面活性剂为关键的裂解机制。 体外工作将检查：1）影响表面活性剂和酶之间相互作用的消化动力学； 2) 细菌消化的速率和程度，3) 温度和反应物浓度对溶菌的影响，4) 肠道暴露时间对消化运动的影响。 将采用温度和食品质量的体内实验来测试体外研究的预测。

P.I. Plante, Craig J. Proposal #: 9504505 PROJECT ABSTRACT Bacteria serve dual roles in sedimentary systems: as mineralizers of organic detritus and as food for protozoans and invertebrates. The biomass, production, and community composition of bacteria contribute to the character of these roles. The primary objective of the research is to assess the importance of deposit-feeder ingestion to both qualitative and quantitative aspects of sedimentary bacterial communities. The principal animal selected for intensive study is the deposit-feeding polychaete, Arencola marina. Other polychaetes (Amphitrite johnstoni and Clymenella torquata), hemichordates (Stereobalanus canadensis and Saccoglossus kowlevskyi), an apodous holothuroid (Caudina arenata), and a bivalve mollusc (Macoma balthica) will be investigated for interspecific comparisons. The mechanisms of lysis, keying on digestive surfactants, will be determined. In vitro work will examine 1) the digestive kinetics which affect interactions between surfactants and enzymes; 2) the rate and extent of bacterial digestion, 3) the influence of temperature and reactant concentrations on bacteriolysis, and 4) the effect of gut exposure time on digestive kinematics. In vivo experiments with temperature and food quality will be employed to test predictions resulting from in vitro investigations..