Physiological Role and Phylogenetic Diversity of Termite Gut Symbionts

Breznak 9709000 大约2000种白蚁每年降解10亿吨木质纤维素植物材料和来自其的残留物（例如腐殖质），并且在这样做的过程中从地球上最丰富的一些但难降解和氮贫乏的食物资源中获得营养。为了完成这一壮举，它们已经进化成壮观的共生体，肠道微生物代表了地球上所有已知的生命领域--细菌、产甲烷菌和真核生物（原生动物）。这些微生物在以下方面是重要的：（i）氮经济（通过N2固定和排泄的N再循环）;（ii）从H2 + CO2生产乙酸盐（白蚁的主要碳和能量来源）;和（iii）生产消化酶。然而，一个挥之不去的挫折来源是无法培养（从而更好地理解）白蚁肠道群落的一些主要成员。 螺旋体然而，分子生物学工具现在提供了一种手段来探测白蚁肠道微生物的性质，数量，生理作用和系统发育多样性，而不需要培养。因此，本项目的研究将分子生物学方法与生物化学和生理学研究相结合，以增加我们对白蚁肠道螺旋体以及与白蚁营养和活力相关的各种其他微生物的了解。预计这项研究将继续揭示白蚁作为一个丰富的水库的新的（和很大程度上未开发的）微生物多样性和一个富有成效的系统，发现新的微生物相互作用的原则。

Breznak 9709000 Roughly 2000 species of termites degrade 1 billion tons annually of lignocellulosic plant material and residues derived from it (e.g. humus) and in doing so derive nutrition from some of earth's most abundant, but refractory and nitrogen-poor food resources. To accomplish this feat, they have evolved into spectacular symbioses with gut microorganisms representing all known domains of life on Earth -- Bacteria, methane-producing Archaea, and Eukarya (protozoa). Such microbes are important in: (i) nitrogen economy (via N2-fixation and excretory N-recycling); (ii) production of acetate (a major carbon and energy source for termites) from H2 + CO2; and (iii)production of digestive enzymes. Nevertheless, a lingering source of frustration has been an inability to culture (and thereby better understand) some of the major members of the termite gut community, ea. spirochetes. However, molecular biological tools now afford a means to probe the nature, number, physiological role(s), and phylogenetic diversity of termite gut microbes without the absolute requirement for cultivation. Accordingly, research in this project will integrate molecular biological approaches with biochemical and physiological studies to increase our understanding of termite gut spirochetes, as well as a variety of other microbes relevant to termite nutrition and vitality. It is expected that this research will continue to reveal termites as a rich reservoir of novel (and largely untapped) microbial diversity and a fruitful system for discovering new principles of microbial interactions.