Oxygen and Sulfide Delivery to Intracellular Bacterial Symbionts

几乎所有的双壳类和腹足类软体动物的细胞质血红蛋白的特征，其中化能自养细菌作为内部共生体存在，似乎是至关重要的共生。三个这样的血红蛋白，从鳃的蛤Lucina，已被分离和它们的相互作用与硫化物或氧确定。这些血红蛋白在共生关系中的作用将用含有共生菌、纯化鳃血红蛋白、硫化物和氧的破碎细胞系统来研究。将研究细胞质血红蛋白介导的氧气输送和硫化物输送到细菌共生体的分子机制;将检查血红素或配体的还原对配体解离的影响。我们的理解的手段，使细菌利用二氧化碳利用从硫化物氧化获得的能量，从而支持这种蛤和其他类似的macrobes的生活，应加强这些研究。血红蛋白，存在于某些海洋无脊椎动物的细胞质中，其中一个不寻常的共生关系，涉及内化的化能自养细菌存在的特定角色和机制，将在无脊椎动物的血红蛋白运输氧气和硫化物的细菌的能力方面进行研究。这种相互依赖的微生物和大型有机体是一个日益认识到的一个手段，硫化物，有毒的无脊椎动物，达到共生体，并保护免受氧气的理解，应扩大本研究。//

Cytoplasmic hemoglobins characteristic of nearly all bivalves and gastropod molluscs in which chemoautotrophic bacteria are present as internal symbionts appear vital to the symbiosis. Three such hemoglobins, from gills of the clam Lucina, have been isolated and their interactions with either sulfide or oxygen determined. The role(s) of these hemoglobins in the symbiotic association will now be examined using broken-cell systems containing symbiotic bacteria, kpurified gill hemoglobins, sulfide, and oxygen. The molecular mechanisms of cytoplasmic hemoglobin-mediated oxygen delivery and sulfide delivery to the bacterial symbionts will be studied; the effects of reduction of either heme or the ligand on ligand dissociation will be examined. Our understanding of the means whereby the bacteria utilize carbon dioxide using energy gained from sulfide oxidation, thus supporting life of this clam and other similar macrobes should be enhanced by these studies. The particular roles and mechanisms whereby hemoglobins, present in the cytoplasm of certain marine invertebrates in which an unusual symbiosis involving internalized chemoautotrophic bacteria exists, will be studied in terms of the ability of the invertebrate's hemoglobins to transport oxygen and sulfide to the bacteria. This inter-dependence of micro- and the macro-organism is an increasingly recognized one; an understanding of the means whereby sulfide, toxic to the invertebrate, reaches the symbiont and is protected from oxygen should be enlarged by this study. //