BIOADHESIVE SECRETION OF SECRETORY ORGANELLES IN FORAMINIFERA

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 摘要： 凝集有孔虫原生生物的测试（壳）由矿物颗粒组成，这些矿物颗粒被耐化学性的生物水泥（即，“细胞外基质”的“生物粘附剂”）。 在测试形态发生过程中，它们的伪足网络从沉积物中收集矿物颗粒，以适当的数量和位置分泌生物粘合剂，并通过它们的协调运动，塑造这些建筑优雅的结构。 高丰度的关键，巨大的凝集物种在我们的南极洲收集网站，使这个有孔虫群落独特的适合研究凝集试验建设的具体方面，并解决有关的问题，该组的发育。我们的形态发生研究将集中在Astrammina rara -一个巨大的单细胞系统，使我们能够研究生物粘附剂在冷适应海洋生物中的分泌和组装，而不会出现后生动物系统常见的细胞-细胞和细胞-组织相互作用的并发症。 使用延时视频显微镜，光和电子显微镜细胞化学和聚丙烯酰胺凝胶电泳的研究将提供在细胞和生化水平的分析凝集试验建设的信息。 材料测试和有限元分析将表征A.拉拉的生物粘合剂 从实用的角度来看，这种环境安全的生物粘合剂结合免疫球蛋白，并具有可能具有生物技术应用的有用材料特性。最后，分子系统发育分析的基础上，选定的物种的18 S rDNA序列数据，将提供一个急需的框架，以确定这个重要的原生动物类群的演变。 在RVBC先前的工作中，对所有的稀有黄芪进行了粘附蛋白的免疫标记。 在以前未被确认的深海有孔虫中发现了具有膜自养细菌，在有孔虫共生体连接复合体处具有膜特化（质膜的复杂内陷）。厚切片的高压电子显微镜对于确定这些内陷的3D结构至关重要。 [鲍泽，S. S.，Bernhard，J.M.，Habura，A.，和Gooday，A. J.（2002）南极洲探险者湾一种类似异源有孔虫的三角形Astrammina triangularis（Earland）的结构、分类学和生态学。J. Foraminiferal Res. 32：364-374.]我们与英国南安普顿大学南安普顿海洋学中心的Ana da Silva博士合作，将分子和结构数据集结合起来，研究极地有孔虫是从深海物种进化而来，还是从深海物种进化而来。 我们发现从阿拉伯海采集的标本根本不是有孔虫，而是一个很少被研究的姐妹群巨型有壳变形虫。这些“格罗米亚”物种对他们在海平面以下1000米处经历的低氧条件表现出了迷人的适应性。具体来说，我们发现细菌停靠在沿着它们表面的特定点上--这些可能是帮助它们在缺氧中生存的化学自养生物。 在上一个报告期内，HVEM用于一项研究，以比较和对比异格伪足与有孔虫网状伪足，并记录是否存在微管和有孔虫特有的其他细胞器。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. ABSTRACT: The tests (shells) of agglutinated foraminiferan protists are composed of mineral grains tightly bound by a chemically-resistant, biological cement (i.e., "bioadhesive" of "extracellular matrix"). During test morphogenesis, their pseudopodial networks collect mineral grains from the sediment, secrete bioadhesives in the proper amount and location, and through their coordinated movements, sculpt these architecturally-elegant structures. The high abundance of key, giant agglutinated species at our antarctic collection site makes this foraminiferan community uniquely suited for studying specific aspects of agglutinated test construction, and addressing related questions concerning the phylogeny of the group. Our morphogenetic studies will focus on Astrammina rara - a giant unicellular system that allows us to study the secretion and assembly of bioadhesive in a cold-adapted marine organism without the complications of cell-cell and cell-tissue interactions common to the metazoan systems. Studies using time-lapse videomicroscopy, light -and electron-microscopic cytochemistry and polyacrylamide gel electrophoresis will provide information on agglutinated test construction at the cellular and biochemical levels of analysis. Materials testing with finite element analysis will characterize the mechanical properties of A. rara's bioadhesive. From a practical standpoint, this environmentally-safe bioadhesive binds immunoglobulins and has useful material properties that may have biotechnological applications. Finally, molecular phylogenetic analyses, based on 18S rDNA sequence data of selected species, will provide a much-needed framework for determining the evolution of this important protisan taxon. In previous work at the RVBC, whole mounts of Astrammina rara were immunolabelled for adhesion proteins. Previously-unidentified foraminifera from the deep sea were found to have cemoautotrophic bacteria, with membrane specializations (intricate invaginations of the plasma membrane) at the foram-symbiont junctional complex. HVEM of thick sections was essential in determining the 3D structure of these invaginations. [Bowser, S.S., Bernhard, J.M., Habura, A., and Gooday, A.J. (2002) Structure, taxonomy and ecology of Astrammina triangularis (Earland), an allogromid-like agglutinated foraminifer from explorers cove, Antartica. J. Foraminiferal Res. 32: 364-374.] In collaboration with Dr. Ana da Silva of the Southampton Oceanographic Centre, University of Southampton, UK, we combined molecular and structural datasets to investigate whether the polar foraminifera evolved from deep-sea species, or vice-versa. We found that the specimens collected from the Arabian Sea were not foraminifera at all, but rather a rarely-studied sister group of giant testate amoebae. These "Gromia" species showed fascinating adaptations to the low oxygen conditions they experienced 1000 meters below sea level. Specifically, we found bacteria docked at specific points along their surfaces -- these were probably chemoautotrophs that help them survive hypoxia. In the previous reporting period, the HVEM was used in a study to compare and contrast allogromia pseudopodia with reticulopodia of foraminferia, and to document the presence or absence of microtubules and other organelles characteristic of Foraminifera.