Microbial Genome Sequencing: Genome Analysis of Galdieria sulphuraria - A Unique Unicellular Thermo-Acidophilic Photosynthetic Microorganism

极端环境中常常居住着极端微生物，它们几乎都是原核生物。然而，红色微型藻硫藻是一种真核生物，在硫磺温泉等极端栖息地(PH值0.05至4，温度高达56摄氏度)，可占生物量的90%。这块活化石的基因序列应该能揭示现代真核生物的进化过程。Galdieria依靠50多种不同的碳源茁壮成长，包括一些稀有的糖和糖醇-这证明了大量的代谢基因，几乎没有其他生物能与之匹敌，而且可能是生物技术中丰富的耐热酶来源。此外，这种生物还能耐受镉、汞、铝或镍等有毒金属离子，这表明它在生物修复方面有潜在的用途。从嗜热菌中分离出来的蛋白质通常更容易结晶，这使得Galdieria蛋白质在结构生物学研究中很有价值。最后，Galdieria光合作用的高温处于这一过程的极端范围；因此，这种生物很可能被证明是对光合作用装置进行物理研究的有用模型。硫磺乳杆菌的基因组将被测序。将对序列进行整理和注释，提供给公共数据库，并将开发专门的数据库来利用这些数据。这项研究将在真核生物对极端环境的适应、蛋白质热稳定性的分子机制以及代谢途径对极端应激的适应中的基因调控的协调方面产生丰富的知识。此外，该项目将增加对基因组进化的理解，以及植物和质体的系统发育。

Extreme environments are frequently inhabited by extremophiles, which are almost always prokaryotic organisms. However, the red micro-alga Galdieria sulphuraria (Cyanidiales) is a eukaryote that can represent up to 90% of the biomass in extreme habitats such as hot sulfur springs (pH 0.05 to 4; temperatures up to 56 degrees C). The gene sequences of this living fossil should reveal much about the evolution of modern eukaryotes. Galdieria thrives on more than 50 different carbon sources, including a number of rare sugars and sugar alcohols - evidence of a large repertoire of metabolic genes equaled by few other organisms and a potentially rich source of thermo-stable enzymes for biotechnology. Moreover, this organism tolerates toxic metal ions such as cadmium, mercury, aluminum or nickel, suggesting potential use in bioremediation. Proteins isolated from thermophiles frequently crystallize more readily, making Galdieria proteins valuable for structural biology studies. Finally, the high temperatures under which Galdieria photosynthesizes are at the extreme ranges for this process; thus this organism will likely prove a useful model for physical studies on the photosynthetic apparatus. The genome of Galdieria sulphuraria will be sequenced. Sequences will be collated and annotated, provided to public databases, and specialized databases for the exploitation of this data will be developed. This research will generate a wealth of knowledge on the adaptation of eukaryotic organisms to extreme environments, on molecular mechanisms of protein thermo-stability, and on the coordination of gene regulation in adaptation of metabolic pathways to extreme stress. In addition, the project will add to the understanding of genome evolution, and the phylogeny of plants and plastids.