Identity, function, and transport of lignocellulose-active enzymes in wood-eating (xylotrophic) bivalves (shipworms)

船蛆是一种蠕虫状的海洋蛤类，它们在木头上打洞，用木头作为食物和住所。因为很少有动物吃木头，所以人们对那些能吃木头的动物很感兴趣。在这个研究者的实验室里，以前的研究表明，船蛆消化木材的方法与其他任何动物都不同。大多数吃木头的动物，例如白蚁或吃木头的蟑螂，都是在消化系统中的细菌和其他微生物产生的酶的帮助下吃木头的。 然而，船蛆的消化系统中几乎没有细菌。相反，它们依赖于生活在鳃细胞内的细菌共生体来产生它们所需的消化酶。 这是独一无二的，因为没有其他已知的动物依赖于细胞内共生体来产生消化酶。在该项目中，将鉴定这些细菌产生的酶，以表征其功能，并确定这些酶如何从船蛆鳃细胞内转运到消化系统。这些酶具有潜在的价值，因为它们将地球上最丰富的生物材料木材转化为可溶性糖，这些糖可以发酵成可再生的生物燃料，例如乙醇。它们还可用于生产或加工纸张、纺织品、洗涤剂、食品、动物饲料和废料。该项目将有助于海洋基因组遗产的正在进行的博士后培训和研究生教育计划，环境素养的公众宣传，以及本科生，高中生和少数民族学生的实习计划。研究人员还将与太平洋西北部的同事合作，为阿拉斯加原住民学生和教师开发一个STEM教育计划，将船蛆生物学与传统的阿拉斯加原住民生态知识和西方科学相结合;该计划将利用翻译成海达语的教育课程。

Shipworms are worm-like marine clams that burrow in wood, using wood for both food and shelter. Because few animals eat wood, there is great interest in those that can. Previous research in this investigator's laboratory suggested that shipworms digest wood using a method that is different from any other animal. Most animals that eat wood, e.g. termites or wood-eating roaches, do so with the help of enzymes made by bacteria and other microbes that live in their digestive systems. Shipworms, however, have few bacteria in their digestive systems. Instead, they rely on bacterial symbionts that live inside the cells of their gills to produce the digestive enzymes they need. This is unique because no other known animal relies on intracellular symbionts to produce digestive enzymes. In this project, the enzymes produced by these bacteria will be identified in order to characterize their functions, and to determine how these enzymes are transported from inside the cells of the shipworm's gills to their digestive system. These enzymes are potentially valuable because they convert wood, the most abundant biomaterial on earth, into soluble sugars that can be fermented into renewable biofuels, e.g. ethanol. They may also be used in production or processing of paper, textiles, detergents, food, animal feed and waste materials. This project will contribute to Ocean Genome Legacy's ongoing postdoctoral training and graduate education programs, public outreach for environmental literacy, and internship programs for undergraduate, high school, and minority students. The investigators will also work with colleagues in the Pacific Northwest to develop a STEM education program for Native Alaskan students and teachers that integrates shipworm biology with traditional Native Alaskan ecological knowledge and Western science; this program will utilize educational curricula translated into the Haida language.