THREE DIMENSIONAL RECONSTRUCTIONS OF ARCHAEA

古细菌的三维重建

• 批准号: 7354996
• 负责人: NORMAN R PACE
• 金额: $ 2.81万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-26 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7354996
• 关键词: Archaea; DNA; Salmonella; bacteria; molecular /cellular imaging

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. The phylogenetic tree of all known organisms comprises three distinct branches: Eucarya, Bacteria and Archaea. The Archaeal branch was only recently recognized as a coherent group that is phylogenetically distinct from Bacteria. Our knowledge of the fine structure of prokaryotic cells (Archaea and Bacteria) is significantly less than what we know about their biochemical and molecular organization. This is due primarily to limitations in preservation methods and, to some extent, in instrumentation. Advances in modern techniques of rapid freezing and freeze-substitution have overcome some of these problems, yielding elegant preservation of some prokaryotic organisms. Since molecular studies suggest that Archaea have more in common with Eukaryotes than with Bacteria, in terms of transcription, translation and other DNA related processing mechanisms, the morphology of these organisms may yield a wealth of biological information. Whole cell images of high-pressure frozen, freeze-substituted Sulfolobus solfataricus have been captured via serial section tomography. As a control, whole cell images of the bacterium Salmonella have been prepared in an identical manner. The whole cell tomograms have allowed the enumeration of several different structures in Sulfolobus, at least one of which varies according to the presence or absence of glucose in the medium in which the cells are grown. DNA preservation, previously a problem, is currently quite good with the addition of the sucrose polymer Ficoll-70 to the growth medium just prior to freezing. Lowicryl embedded Sulfolobus has been successfully probed for DNA and verified by tomographic ribosome exclusion models. Work will continue on the characterization of nuclear body structure of Sulfolobus and Salmonella during the next year. The principal rate determining step going forward is the labor intensive nature of segmentation.

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。所有已知生物的系统发育树包括三个不同的分支：真核菌、细菌和古生菌。古细菌分支直到最近才被认为是一个在系统发育上与细菌不同的连贯类群。我们对原核细胞（古生菌和细菌）精细结构的了解远远少于我们对其生化和分子组织的了解。这主要是由于保存方法的限制，在某种程度上，仪器的限制。现代快速冷冻和冷冻替代技术的进步已经克服了其中的一些问题，使一些原核生物得以优雅地保存下来。由于分子研究表明，就转录、翻译和其他DNA相关加工机制而言，古细菌与真核生物比细菌有更多的共同之处，因此这些生物的形态可能产生丰富的生物信息。高压冷冻、冷冻替代的solfataricus Sulfolobus solfataricus的全细胞图像已通过连续切片断层扫描捕获。作为对照，用同样的方法制备了沙门氏菌的全细胞图像。全细胞断层扫描可以列举出Sulfolobus中几种不同的结构，其中至少有一种结构根据细胞生长的培养基中葡萄糖的存在或缺失而变化。DNA保存，以前是一个问题，目前在冷冻前添加蔗糖聚合物Ficoll-70到培养基中就很好了。Lowicryl包埋的Sulfolobus已成功探测DNA，并通过层析核糖体排除模型进行验证。明年将继续对沙门菌和沙门菌的核体结构进行表征。决定未来费率的主要步骤是分割的劳动密集型性质。