U.S.-Australian Cooperative Research on the Analysis and Manipulation of the Algal Carbon Dioxide Concentrating Mechanism

该奖项将支持爱荷华州立大学植物系Martin H.Spalding教授和堪培拉澳大利亚国立大学Murray R.Badger博士在美澳合作科学计划下的一个为期两年的合作项目。科学家们将研究单细胞藻类莱茵衣藻的光合作用过程。这种单细胞藻类和其他单细胞藻类在利用外部无机碳进行光合作用方面非常有效，并表现出其他有趣的光合作用特性。合作研究人员认为，这些影响是藻类细胞内二氧化碳浓度水平的结果，藻类细胞内二氧化碳浓度水平明显高于大多数高等植物。研究人员提出了一种“二氧化碳浓缩机制”，涉及需要能量的无机碳(如二氧化碳或碳酸氢根离子)进入藻细胞和藻细胞内的运输，然后酶催化转化累积的碳酸氢根离子以产生更高水平的二氧化碳。这个合作项目的目的是更好地了解运输机制，并确定酶(碳酸酐酶)在细胞内的位置。美国和澳大利亚的研究小组一直活跃在这一研究领域，使用互补的方法和技术。斯伯丁教授和他的同事们侧重于微藻中二氧化碳浓缩机制的分子遗传学研究，而澳大利亚的巴杰博士和他的团队则专注于蓝藻的相关研究，并开发了特殊的质谱学和离心法来协助分析。合作项目将建立在两个小组的优势基础上，主要研究人员以及他们的博士后同事将进行交流。

This award will support a two-year collaborative project between Professor Martin H. Spalding, Department of Botany, Iowa State University, and Dr. Murray R. Badger, Australian National University, Canberra, under the U.S.-Australia Cooperative Science Program. The scientists will study aspects of the photosynthetic process in the unicellular alga Chlamydomonas reinhardtii. This and other unicellular algae are very efficient in their use of external inorganic carbon for photosynthesis, and exhibit additional interesting photosynthetic characteristics as well. The cooperating researchers believe these effects are the result of intracellular carbon dioxide concentration levels in the algae which are significantly greater than in most higher plants. A "carbon dioxide-concentrating mechanism" has been proposed by the investigators which involves energy-requiring transport of inorganic carbon (as carbon dioxide or bicarbonate ion) into and within the algal cells, followed by enzyme-catalyzed conversion of accumulated bicarbonate ion to yield enhanced levels of carbon dioxide. It is the aim of this cooperative project to understand better the transport mechanism and to determine the location of the enzyme (carbonic anhydrase) within the cell. Both the U.S. and Australian groups have been active in this area of research, using complementary approaches and techniques. Professor Spalding and his colleagues have emphasized molecular genetic studies of the CO2-concentrating mechanism in microalgae, while Dr. Badger and his group in Australia have focused their related efforts on cyanobacteria, and have developed special mass spectrometric and centrifugation techniques to aid in the analyses. The cooperative project will build upon the strengths of both groups, and will involve exchanges by the principal investigators as well as by their postdoctoral associates.