Novel Aspects of Phosphorus Metabolism in Thermophilic Cyanobacteria

磷是遗传信息、能量代谢、结构和细胞信号分子的关键组成部分，但在一些重要的生态系统中往往是限制性营养素。因此，了解不同来源的磷（如磷酸盐和膦酸盐）是如何获得和回收的环境是至关重要的。包括蓝藻在内的原核生物在许多环境中对磷、碳、氮的生态地球化学循环起着重要作用。陆地生物圈中生物有效磷化合物的总水平知之甚少，在不同的生态系统中可能有很大的差异。 此外，膦酸酯（具有稳定的C-P键，因此不易降解）的合成和释放到环境中是相当重要的，因为它们在各种工业中广泛使用。因此，许多陆地和水生生态系统受到污染。由于P是一种关键的营养素，细菌已经进化出复杂的方法来感知和识别P的可用来源，包括膦酸盐。极端嗜热蓝藻分离温泉垫有一个复杂的P收购和代谢电路，也有能力代谢膦酸盐。这些与环境相关的蓝藻将被用来解剖和探索有关磷/膦酸盐利用的调节及其与环境中碳代谢和循环的联系的问题。将定义使用转录分析和生化测定的各种磷源的利用的相似性和差异。将确定在规定条件下分离物中各种P物质的水平和垫中的环境参数。针对这些蓝藻突变体进行详细的遗传分析是可行的。将特定条件下的响应与环境中直接测量的响应相关联，将有助于了解微生物群落如何响应和适应环境中的磷水平。更广泛的影响磷通常是限制海洋和陆地环境中生长的营养素。相反，各种人为有机磷化合物（杀虫剂，除草剂等）也可能是工业废水中的主要污染物，并导致水体的富营养化。因此，近年来，有害和无法管理的蓝藻和藻类大量繁殖的现象有所增加。关于蓝藻如何有效地获取和代谢不同的有机磷源的见解可能广泛适用于其他光合微生物，特别是海洋中的光合微生物。这些发现也可能是一些意义上的生物修复研究，因为有迹象表明，膦酸盐利用基因可以横向跨谱系转移。在发展这个研究计划的过程中，本科生，研究生和博士后研究员将得到培训。位于斯坦福大学校园内的卡内基研究所致力于研究，并提供跨学科研究的优秀培训和参加人数众多的暑期实习生计划。与学生人数众多且多样化的圣何塞州立大学以及奥克兰米尔斯学院（一所历史悠久、历史悠久的女子学院）的紧密联系将使学生在科学领域的代表性通常不足。最后，由于这项研究涉及黄石国家公园的微生物，研究人员将与公园当局合作，为他们广泛和广泛使用的推广计划做出贡献。

Phosphorus is a key component of genetic information, energy metabolism, structural and cell signaling molecules, but is often a limiting nutrient in several important ecosystems. Thus an understanding of how different sources of P (such as phosphates and phosphonates) are acquired and recycled in the environment is of critical importance. Prokaryotes, including cyanobacteria, contribute importantly to the biogeochemical cycling of phosphorus (P), carbon (C) and nitrogen (N) in many environments. Little is known about the total levels of bioavailable P compounds in the terrestrial biosphere and there can be wide variation in different ecosystems. Furthermore, the synthesis and release of phosphonates (which have a stable C-P bond and are therefore not easily degraded) into the environment is quite significant because of their extensive use in various industries. As a consequence many terrestrial and aquatic ecosystems are contaminated. Because P is a key nutrient, bacteria have evolved sophisticated ways to sense and scavenge available sources of P, including phosphonates. Extremophilic cyanobacterial isolates from hot spring mats have a complex P acquisition and metabolism circuitry and also have the capacity to metabolize phosphonates. These environmentally relevant cyanobacteria will be used to dissect and explore questions regarding the regulation of phosphorus/phosphonate utilization and its connection to carbon metabolism and cycling in the environment. Similarities and differences in the utilization of various phosphorus sources using transcript analysis and biochemical assays will be defined. Levels of various P species in the isolates under defined conditions and environmental parameters in the mats will be determined. Targeted mutants of these cyanobacteria has made detailed genetic analysis feasible. Correlating responses under defined conditions and those measured directly in the environment will allow for an understanding of how microbial communities respond and acclimate to phosphorus levels in the environment.Broader ImpactsPhosphorus is often a nutrient that limits growth in marine and terrestrial environments. Conversely, various anthropogenic organophosphorus compounds (insecticides, herbicides etc.) can also be major contaminants in industrial effluents and contribute to the eutrophication of water bodies. Consequently, harmful and unmanageable cyanobacterial and algal blooms have increased in recent years. The insights gained about how cyanobacteria effectively access and metabolize different organophosphorus sources maybe broadly applicable to other photosynthetic microbes, particularly those in the oceans. These findings may also be of some significance in bioremediation studies since there is an indication that phosphonate utilization genes can be transferred laterally across lineages. In the process of developing this research program, undergraduates, graduate students and post-doctoral fellows will be trained. The Carnegie Institution which is located on the campus of Stanford University is dedicated to research and offers excellent training in interdisciplinary research and a well-attended summer intern program. Strong ties with San Jose State University which has a large and diverse student body and with Mills College, Oakland, a historical and well-established women's college, will allow for training of students typically under-represented in science. Finally, since this research involves microbes at Yellowstone National Park, researchers will work with Park authorities to contribute to their extensive and widely used outreach program.