Test Morphogenesis in a Giant Antarctic Foraminiferan

巨大的有孔虫原生生物，Astrammina rara， 一种矿物颗粒的外壳（测试）， 耐化学性、生物粘固剂或细胞外基质。 初步观察表明，A.拉拉分枝网 而关闭的伪足则从 沉积物，分泌测试矩阵，并通过其协调 活动，雕刻测试。 大尺寸，易于操作， 高丰度A.南极采集点的拉拉 这种生物体特别适合研究测试的特定方面， 建设 因为A. rara是一个巨大的单细胞系统， 关于细胞外基质组装的一般问题 冷适应生物体中的成分可以在没有 后生动物系统常见的并发症。 在某些方面的适应 测试构建中涉及的基本细胞过程是 特别感兴趣，因为这些过程被抑制， 从温带到温带， 气候 将使用各种生物技术方法来获得 关于细胞和分子实验室的测试构建信息 分析水平。 完成拟议的研究将不会 只会帮助解决一个有趣而长期的生物学问题 问题，但也将提供一个框架，为未来的分子 对这种重要原生生物的生理和进化的研究 分类群。

The giant foraminiferan protist, Astrammina rara, is protected by an outer shell (test) of mineral grains tightly bound by a chemically-resistant, biological cement or extracellular matrix. Cursory observations indicate that A. rara's network of branching and anastomosing pseudopodia collects larger particulates from the sediment, secretes the test matrix, and through its coordinated activity, sculpts the test. The large size, ease of handling, and high abundance of A. rara at the Antarctic collection site makes this organism uniquely suited for studying specific aspects of test construction. Because A. rara is a giant single-cell system, general questions regarding the assembly of extracellular matrix components in a cold-adapted organism can be studied without the complications common to metazoan systems. Adaptations in certain basic cellular processes involved in test construction are of particular interest because these processes are inhibited by subzero temperatures in the cells of organisms from temperate climates. Various biotechnological methods will be used to gain information on test construction at the cellular and molecular levels of analysis. Completion of the proposed studies will not only help solve an interesting and longstanding biological question, but will also provide a framework for future molecular studies of the physiology and evolution of this important protistan taxon.