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

船虫是一种蠕虫状的海蚌，它们在木头上挖洞，用木头做食物和庇护所。因为很少有动物吃木头，所以人们对那些会吃木头的动物很感兴趣。这位研究员的实验室之前的研究表明，船虫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，都是在细菌和其他生活在消化系统中的微生物制造的酶的帮助下做到这一点的。然而，船虫的消化系统中几乎没有细菌。取而代之的是，它们依靠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细胞内的共生体来产生消化酶。在这个项目中，将鉴定这些细菌产生的酶，以确定它们的功能，并确定这些酶是如何从船虫的鳃细胞内运输到它们的消化系统的。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，可以发酵成可再生的生物燃料，如乙醇。它们还可用于纸张、纺织品、洗涤剂、食品、动物饲料和废物的生产或加工。该项目将为Ocean Genome Legacy正在进行的博士后培训和研究生教育计划、环境素养的公共宣传以及本科生、高中生和少数族裔学生的实习计划做出贡献。调查人员还将与太平洋西北地区的同事合作，为阿拉斯加原住民的学生和教师制定STEM教育计划，将船虫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.