Collaborative Research: Capturing the Elusive 37:4 Alkenone-predominating Lacustrine Haptophyte: Alkenone Biosynthesis, Genetics and Culture Manipulation

触生藻类最近被认为是世界上最丰富和最多样化的初级生产者-S海洋，这使得它们的代谢和碳固定途径问题变得至关重要。由等鞭毛目藻类产生的烯酮类脂广泛存在于世界各地的海洋和湖泊中，是重建古温度的宝贵工具。然而，人工培养的半生生物与沉积物中观察到的烯酮分布之间的不匹配阻碍了烯酮作为湖泊古温度指标的使用。为了有信心地将烯酮不饱和度应用于湖泊古温度重建，有必要利用包括培养、脂质和分子表征在内的一系列技术来充分了解湖泊中产生烯酮的半植体的生物学和生物化学。这项提议建立在我们成功地获得了第一个稳定的湖相半裸藻类增菌培养的基础上，该藻类主要产生C37：4烯酮，在淡水和咸水环境中丰富的烯酮。我们的研究将促进多学科合作(有机地球化学、分子生物学、生理学、古气候学、湖泊学)研究重要的生物、地球化学和古气候学问题，并允许对研究生和本科生进行跨学科的培训。与布朗大学现有的NSF资助的GK-12项目的密切互动将使高中教师参与实地考察和实验室研究，在当地学校的讲座将广泛传播我们的研究。这项研究产生的数据还将被纳入针对高级本科生/研究生的有机地球化学和分子生物学课程，并帮助支持一名全日制研究生，重点是湖泊上生植物。

Haptophyte algae are recently credited as the most abundant and diverse primary producers in the world?s oceans, rendering their metabolic and carbon fixation pathways issues of utmost importance. Alkenone lipids produced by haptophyte algae of the order Isochrysidales occur ubiquitously in the world?s ocean and in numerous lakes and are an invaluable tool for paleotemperature reconstructions. However, the mismatch between cultured haptophytes and observed alkenone distributions in sediments has hindered the use of alkenones as a paleotemperature proxy in lakes. In order to confidently apply the alkenone unsaturation for paleotemperature reconstructions in lakes, it is necessary to fully understand the biology and biochemistry of the lacustrine alkenone-producing haptophytes using a consortium of techniques including culturing, lipid and molecular characterization. This proposal builds on our success in obtaining the first stable enrichment culture for a lacustrine haptophyte alga that produces predominantly C37:4 alkenones, the alkenone abundant in freshwater and brackish environments. Systematic sampling of lake water and plankton and in situ measurements of environmental parameters at Lake George, ND combined with extensive manipulation of our haptophyte culture will permit identification of the triggers for haptophyte algal blooms.Our study will promote multidisciplinary collaboration (organic geochemistry, molecular biology, phycology, paleoclimatology, limnology) to studying important biological, geochemical and paleoclimatological problems, and allow cross-discipline training of graduate and undergraduate students. Close interaction with Brown University's existing NSF funded GK-12 program will bring high school teachers to participate in field trips and laboratory research, and lectures given at local schools, will broadly disseminate our research. Data generated from this research will also be incorporated into organic geochemistry and molecular biology courses targeted at the advanced undergraduate/graduate level and help support a full-time graduate student focusing on lacustrine haptophytes.